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Helen martins e mauro betting tips 1x2

Surface charge heterogeneities on the collector surfaces and especially within the ARS-nHAP population were contributing causes for the hyperexponential RPs. The whole set up was interfaced with a computer for easy data acquisition. It was observed that For instance, Al2 SO4 3 is used in water Surface charge measurement using an electrostatic probe.

During the s, the first measurements of charge on dielectric surfaces using simple electrostatic probes were reported. However it is only within the last 10 years that a proper understanding of the probe response has been developed. This situation arose as a consequence of the earlier studies Small amplitude variable charge dust Bernstein-Greene-Kruskal double layers.

B, Bab-Ezzouar, B. The nature of the dust BGK-DLs compressive or rarefactive , their strength and thickness depend sensitively on the net negative charge residing on the grain surface , the dust grain dynamics and, more interestingly, on the ion-to-electron temperatures ratio. Theory of the surface dipole layer and of surface tension in liquids of charged particles.

The problem of the surface density profiles and of the surface tension of a two-component liquid of charged particles in equilibrium with its vapour is examined. The exact equilibrium conditions for the profiles are given in terms of the inverse response functions of the inhomogeneous fluid, and alternative exact expressions for the surface tension are derived.

The use of a density gradient expansion reduces the problem to knowledge of properties of a homogeneous charged fluid on a uniform neutralizing background, in which the total particle density and the charge density are independent variables.

Additional simplifications are discussed for special cases for which a perturbative treatment of the surface charge density profile can be developed, and in particular for nearly symmetric ionic liquids and for simple liquid metals. Adsorption properties of subtropical and tropical variable charge soils: Implications from climate change and biochar amendment.

This review paper attempts to summarize the progress made in research efforts conducted over the last years to study the surface chemical properties of the tropical and subtropical soils, usually called variable charge soils, and the way they response to different management practices.

The paper is composed of an introductory section that provides a brief discussion on the surface chemical properties of these soils, and five other review sections. The focus of these sections is on the evolution of surface chemical properties during the development of the variable charge properties second section , interactions between oppositely charged particles and the resulting effects on the soil properties and especially on soil acidity third section , the surface effects of low molecular weight organic acids sorbed to mineral surfaces and the chemical behavior of aluminum fourth section , and the crop straw derived biochar induced changes of the surface chemical properties of these soils fifth section.

A discussion on the effect of climate change variables on the properties of the variable charge soils is included at the end of this review paper sixth section. Scattered surface charge density: A tool for surface characterization. We demonstrate the use of nonlocal scanning tunneling spectroscopic measurements to characterize the local structure of adspecies in their states where they are significantly less perturbed by the probe, which is accomplished by mapping the amplitude and phase of the scattered surface charge density.

Metastable states of plasma particles close to a charged surface. Shavlov, A. The free energy of the plasma particles and the charged surface that form an electroneutral system is calculated on the basis of the Poisson-Boltzmann equation. It is shown that, owing to correlation of light plasma particles near the charged surface and close to heavy particles of high charge , there can be metastable states in plasma. The corresponding phase charts of metastable states of the separate components of plasma, and plasma as a whole, are constructed.

These charts depend on temperature, the charge magnitude, the size of the particles, and the share of the charge of the light carriers out of the total charge of the plasma particles. Surface charging , discharging and chemical modification at a sliding contact. Electrostatic charging , discharging, and consequent surface modification induced by sliding dissimilar surfaces have been studied.

The surface-charge related phenomena were monitored by using a home-built capacitive, non-contact electrical probe, and the surface chemistry was studied by X XPS analysis showed a marginal deoxidation effect on the polyester disks due to the charging and discharging of the surfaces. Moreover, these XPS results clearly Charge state of ions scattered by metal surface.

A model for description of charge distributions for scattering of heavy ions in the keV region, on metal surfaces developing and improving the method of Van der Weg and Bierman, and taking into account the connection between the ion charge state and scattering kinematics, is proposed. It is shown that multiple charged particles come from ions with a vacancy in the inner shell while the outer shell vacancies give only single charged ions and neutrals.

The approximately linear increase of degree of ionization with normal velocity, and the non-monotonic charge dependence of the energy spectrum established by Chicherov and Buck et al is explained by considering irreversible neutralization in the depth of the metal, taking into account the connection of the charge state with the shape of trajectory and its location relative to the metal surface.

The dependence of charge state on surface structure is discussed. Some new experiments are proposed. Geometry, charge distribution, and surface speciation of phosphate on goethite. The surface speciation of phosphate has been evaluated with surface complexation modeling using an interfacial charge distribution CD approach based on ion adsorption and ordering of interfacial water.

In the CD model, the charge of adsorbed ions is distributed over two electrostatic potentials in. Here, using both experimental and theoretical approaches, we demonstrated that the surface layers of the perovskite crystals may acquire a high concentration of positively charged vacancies with the complementary negatively charged halide ions pushed to the surface.

This charge separation near the surface generates an electric field that can induce an increase of optical band gap in the surface layers relative to the bulk. We found that the charge separation, electric field, and the amplitude of shift in the bandgap strongly depend on the halides and organic moieties of perovskite crystals. Our findings reveal the peculiarity of surface effects that are currently limiting the applications of perovskite crystals and more importantly explain their origins, thus enabling viable surface passivation strategies to remediate them.

Surface charges for gravity and electromagnetism in the first order formalism. Gravity theory is written in the tetrad-connection variables. The general derivation starts from the Lagrangian, and uses the covariant symplectic formalism in the language of forms. For gauge theories, surface charges disentangle physical from gauge symmetries through the use of Noether identities and the exactness symmetry condition.

The surface charges are quasilocal, explicitly coordinate independent, gauge invariant and background independent. For a black hole family solution, the surface charge conservation implies the first law of black hole mechanics. As a check, we show the first law for an electrically charged , rotating black hole with an asymptotically constant curvature the Kerr—Newman anti- de Sitter family.

The charges , including the would-be mass term appearing in the first law, are quasilocal. Finally, surface charge formulae for Lovelock gravity coupled to electromagnetism are exhibited, generalizing the one derived in a recent work by Barnich et al Proc. The two different symplectic methods to define surface charges are compared and shown equivalent.

Understanding colloidal charge renormilization from surface chemistry : experiment and theory. Gisler, Thomas; Schulz, S. In this paper we report on the charging behavior of latex particles in aqueous suspensions. We use static light scattering and acid-base titrations as complementary techniques to observe both effective and bare particle charges. Acid-base titrations at various ionic strengths provide the pH dependent charging curves.

The surface chemical parameters dissociation constant of the acidic carboxylic groups, total density of ionizable sites and Stem capacitance are determined from tits of a Stem Effects of image charges , interfacial charge discreteness, and surface roughness on the zeta potential of spherical electric double layers.

We investigate the effects of image charges , interfacial charge discreteness, and surface roughness on spherical electric double layer structures in electrolyte solutions with divalent counterions in the setting of the primitive model. By using Monte Carlo simulations and the image charge method, the zeta potential profile and the integrated charge distribution function are computed for varying surface charge strengths and salt concentrations.

Systematic comparisons were carried out between three distinct models for interfacial charges : 1 SURF1 with uniform surface charges , 2 SURF2 with discrete point charges on the interface, and 3 SURF3 with discrete interfacial charges and finite excluded volume. By comparing the integrated charge distribution function and the zeta potential profile, we argue that the potential at the distance of one ion diameter from the macroion surface is a suitable location to define the zeta potential.

In SURF2 model, we find that image charge effects strongly enhance charge inversion for monovalent interfacial charges , and strongly suppress charge inversion for multivalent interfacial charges. For SURF3, the image charge effect becomes much smaller.

Finally, with image charges in action, we find that excluded volumes in SURF3 suppress charge inversion for monovalent interfacial charges and enhance charge inversion for multivalent interfacial charges. Overall, our results demonstrate that all these aspects, i. Electrostatic behavior of the charge -regulated bacterial cell surface.

The electrostatic behavior of the charge -regulated surfaces of Gram-negative Escherichia coli and Gram-positive Bacillus brevis was studied using numerical modeling in conjunction with potentiometric titration and electrophoretic mobility data as a function of solution pH and electrolyte composition. This knowledge is vital for understanding how cells respond to changes in solution pH and electrolyte composition as well as how they interact with other surfaces.

The latter is especially important due to the widespread use of the Derjaguin-Landau-Verwey-Overbeek DLVO theory in the interpretation of bacterial adhesion. As surface charge and surface potential both vary on a charge -regulated surface , accurate modeling of bacterial interactions with surfaces ultimately requires use of an electrostatic model that accounts for the charge -regulated nature of the cell surface.

Screening model for nanowire surface-charge sensors in liquid. The conductance change of nanowire field-effect transistors is considered a highly sensitive probe for surface charge. However, Debye screening of relevant physiological liquid environments challenge device performance due to competing screening from the ionic liquid and nanowire charge carriers Effect of surface charge of immortalized mouse cerebral endothelial cell monolayer on transport of charged solutes.

Charge carried by the surface glycocalyx layer SGL of the cerebral endothelium has been shown to significantly modulate the permeability of the blood-brain barrier BBB to charged solutes in vivo. The cultured monolayer of bEnd3, an immortalized mouse cerebral endothelial cell line, is becoming a popular in vitro BBB model due to its easy growth and maintenance of many BBB characteristics over repeated passages. We also investigated whether orosomucoid, a plasma glycoprotein modulating the charge of the intact BBB, alters the charge of bEnd3 monolayer.

Surface charge effects in protein adsorption on nanodiamonds. Understanding the interaction of proteins with charged diamond nanoparticles is of fundamental importance for diverse biomedical applications. Here we present a thorough study of protein binding, adsorption kinetics and structure on strongly positively hydrogen-terminated and negatively oxygen-terminated charged nanodiamond particles using a quartz crystal microbalance by dissipation and infrared spectroscopy. By using two model proteins bovine serum albumin and lysozyme of different properties charge , molecular weight and rigidity , the main driving mechanism responsible for the protein binding to the charged nanoparticles was identified.

Electrostatic interactions were found to dominate the protein adsorption dynamics, attachment and conformation. We developed a simple electrostatic model that can qualitatively explain the observed adsorption behaviour based on charge -induced pH modifications near the charged nanoparticle surfaces. Under neutral conditions, the local pH around the positively and negatively charged nanodiamonds becomes very high and low respectively, which has a profound impact on the protein charge , hydration and affinity to the nanodiamonds.

Small proteins lysozyme were found to form multilayers with significant conformational changes to screen the surface charge , while larger proteins albumin formed monolayers with minor conformational changes. The findings of this study provide a step forward toward understanding and eventually predicting nanoparticle interactions with biofluids. Characterization of triboelectrically charged particles deposited on dielectric surfaces.

Nesterov, A. The setup is based on the integration of currents, which are induced in a Faraday cage by insertion of a solid support covered with charged particles. The conductivity of different particle supports was taken into account. The 'blow-off' method, in which the particles are first deposited, and then blown off using an air stream, can be used for characterization of triboelectric properties of particles relative to different surfaces. Breitling KIT.

Understanding colloidal charge renormalization from surface chemistry: Experiment and theory. Gisler, T. The surface chemical parameters dissociation constant of the acidic carboxylic groups, total density of ionizable sites and Stern capacitance are determined from fits of a Stern layer model to the titration data. We find strong evidence that the dissociation of protons is the only specific adsorption process.

Effective particle charges are determined by fits of integral equation calculations of the polydisperse static structure factor to the static light scattering data. A generalization of the Poisson-Boltzmann cell model including the dissociation of the acidic surface groups and the autodissociation of water is used to predict effective particle charges from the surface chemical parameters determined by the titration experiments. We find that the light scattering data are best described by a model where a small fraction of the ionizable surface sites are sulfate groups which are completely dissociated at moderate pH.

These effective charges are comparable to the predictions by a basic cell model where charge regulation is absent. Charging behavior of multi-component display-type i. It has been hypothesized that water dissociation, along with the corresponding hydroxylation of the glass surface , are important processes related to charging in glass-metal contact systems. Calculated NBO surface concentrations correlate well with charge based measurements on laboratory fabricated CAS surfaces.

Surface charging sensitivity with respect to NBO concentration decreases as the relative humidity of the measurement environment increases; which should be expected as the highly reactive sites are progressively covered by liquid water layers. Chemical sensors based on surface charge transfer.

The focus of this review is an introduction to chemiresistive chemical sensors. The general concept of chemical sensors is briefly introduced, followed by different architectures of chemiresistive sensors and relevant materials. For several of the most common systems, the fabrication of the active materials used in such sensors and their properties are discussed.

Furthermore, the sensing mechanism, advantages, and limitations of each group of chemiresistive sensors are briefly elaborated. Compared to electrochemical sensors, chemiresistive sensors have the key advantage of a simpler geometry, eliminating the need for a reference electrode.

The performance of bulk chemiresistors can be improved upon by using freestanding ultra-thin films nanomaterials or field effect geometries. Both of those concepts have also been combined in a gateless geometry, where charge transport though a percolation network of nanomaterials is modulated via adsorbate doping. A surface diffuse scattering model for the mobility of electrons in surface charge coupled devices.

An analytical model for the mobility of electrons in surface charge coupled devices is studied on the basis of the results previously obtained, considering a surface diffuse scattering; the importance of the results obtained for a better understanding of the influence of the fringing field in surface charge coupled devices is discussed. Direct quantification of negatively charged functional groups on membrane surfaces.

Surface charge plays an important role in membrane-based separations of particulates, macromolecules, and dissolved ionic species. In this study, we present two experimental methods to determine the concentration of negatively charged functional groups at the surface of dense polymeric membranes. Both techniques consist of associating the membrane surface moieties with chemical probes, followed by quantification of the bound probes. Uranyl acetate and toluidine blue O dye, which interact with the membrane functional groups via complexation and electrostatic interaction, respectively, were used as probes.

The amount of associated probes was quantified using liquid scintillation counting for uranium atoms and visible light spectroscopy for the toluidine blue dye. The techniques were validated using self-assembled monolayers of alkanethiols with known amounts of charged moieties. The surface density of negatively charged functional groups of hand-cast thin-film composite polyamide membranes, as well as commercial cellulose triacetate and polyamide membranes, was quantified under various conditions.

Using both techniques, we measured a negatively charged functional group density of nm -2 for the hand-cast thin-film composite membranes. The ionization behavior of the membrane functional groups, determined from measurements with toluidine blue at varying pH, was consistent with published data for thin-film composite polyamide membranes.

Similarly, the measured charge densities on commercial membranes were in general agreement with previous investigations. The relative simplicity of the two methods makes them a useful tool for quantifying the surface charge concentration of a variety of surfaces , including separation membranes.

Surface charge algebra in gauge theories and thermodynamic integrability. Surface charges and their algebra in interacting Lagrangian gauge field theories are constructed out of the underlying linearized theory using techniques from the variational calculus. In the case of exact solutions and symmetries, the surface charges are interpreted as a Pfaff system.

Integrability is governed by Frobenius' theorem and the charges associated with the derived symmetry algebra are shown to vanish. In the asymptotic context, we provide a generalized covariant derivation of the result that the representation of the asymptotic symmetry algebra through charges may be centrally extended. Comparison with Hamiltonian and covariant phase space methods is made. All approaches are shown to agree for exact solutions and symmetries while there are differences in the asymptotic context.

On the theoretical description of weakly charged surfaces. It is widely accepted that the Poisson-Boltzmann PB theory provides a valid description for charged surfaces in the so-called weak coupling limit. Here, we show that the image charge repulsion creates a depletion boundary layer that cannot be captured by a regular perturbation approach.

The correct weak-coupling theory must include the self-energy of the ion due to the image charge interaction. The image force qualitatively alters the double layer structure and properties, and gives rise to many non-PB effects, such as nonmonotonic dependence of the surface energy on concentration and charge inversion. In the presence of dielectric discontinuity, there is no limiting condition for which the PB theory is valid.

Charged particle discrimination with silicon surface barrier detectors. The application for materials analysis of nuclear reactions that give rise to charged particles is a powerful surface analytical and concentration depth profiling technique.

Spectra of charged particles, with energies in the range 0. The spectra from multi-elemental materials typically encountered in materials research are usually composed of an overlapping superposition of proton, alpha, and other charged particle spectra.

Interpretation of such complex spectra would be simplified if a means were available to electronically discriminate between the detector response to the different kinds of charged particle. We have investigated two methods of discriminating between different types of charged particles. The fast charge pulses from a surface barrier detector have different shapes, depending on the spatial distribution of energy deposition of the incident particle.

Fast digitisation of the pulses, followed by digital signal processing provides one avenue for discrimination. A second approach is to use a thin transmission detector in front of a thick detector as a detector telescope. For a given incident energy, different types of charged particles will lose different amounts of energy in the thin detector, providing an alternative means of discrimination.

We show that both approaches can provide significant simplification in the interpretation of charged particle spectra in practical situations, and suggest that silicon surface barrier detectors having graded electronic properties could provide improved discrimination compared to the current generation of detectors having homogeneous electronic properties. By using two model proteins. Cellulose nanocrystals with tunable surface charge for nanomedicine.

Crystalline nanoparticles of cellulose exhibit attractive properties as nanoscale carriers for bioactive molecules in nanobiotechnology and nanomedicine. For applications in imaging and drug delivery, surface charge is one of the most important factors affecting the performance of nanocarriers.

However, current methods of preparation offer little flexibility for controlling the surface charge of cellulose nanocrystals, leading to compromised colloidal stability under physiological conditions. We report a synthesis method that results in nanocrystals with remarkably high carboxyl content 6. Six fractions of nanocrystals with various surface carboxyl contents were synthesized from a single sample of softwood pulp with carboxyl contents varying from 6.

The proposed method resulted in highly stable colloidal nanocrystals that did not aggregate when exposed to high salt concentrations or serum-containing media. Darkfield hyperspectral imaging and confocal microscopy confirmed the uptake of nanocrystals by selected cell lines without any evidence of membrane damage or change in cell density; however a charge -dependent decrease in mitochondrial activity was observed for charge contents higher than 3.

A high surface carboxyl content allowed for facile conjugation of fluorophores to the nanocrystals without compromising colloidal stability. The cellular uptake of fluoresceinamine-conjugated nanocrystals exhibited a time-dose dependent relationship and increased significantly with doubling of the surface charge.

This paper describes an outline and some examples of three dimensional electric field calculations with a computer code developed at NIRS. In the code, a surface charge method is adopted because of it's simplicity in the mesh establishing procedure. The charge density in a triangular mesh is assumed to distribute with a linear function of the position. The electric field distribution is calculated for a pair of drift tubes with the focusing fingers on the opposing surfaces.

The field distribution in an acceleration gap is analyzed with a Fourier-Bessel series expansion method. The calculated results excellently reproduces the measured data with a magnetic model. Static phenomena at the charged surface of liquid hydrogen. The shape evolution of the equipotentially charged surface of liquid hydrogen layer covering the lower plate of a horizontally arranged diode in external electric fields has been studied experimentally for the first time.

A reconstruction phenomenon the formation of a stationary hump at the flat charged surface at voltages higher than a certain critical U c1 was observed under the conditions of total compensation of the electric field in the bulk liquid by a surface charge. It is shown that the transition of the flat charged surface into the reconstructed state is a phase transition closed to the second order phase transition. The shape evolution of a changed droplet of constant volume suspended at the upper plate of the diode when the stretching electric field and gravity forces act in the same direction was studied as the voltage was increased up to the discharge.

The protective nature of passivation films on zinc: surface charge. The influence of oxide surface charge on the corrosion performance of zinc metals was investigated. Oxidised zinc species zinc oxide, zinc hydroxychloride, zinc hydroxysulfate and zinc hydroxycarbonate with chemical compositions similar to those produced on zinc during atmospheric corrosion were formed as particles from aqueous solution, and as passive films deposited onto zinc powder, and rolled zinc, surfaces.

Synthesized oxides were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and electron probe X-ray microanalysis. The zeta potentials of various oxide particles, as determined by microelectrophoresis, are reported as a function of pH. Particulates containing a majority of zinc hydroxycarbonate and zinc hydroxysulfate crystallites were found to possess a negative surface charge below pH 6, whilst zinc oxide-hydroxide and zinc hydroxychloride crystallites possessed isoelectric points IEP's higher than pH 8.

Electrochemical analysis of the open-circuit potential as a function of time at a fixed pH of 6. Coagulation of dielectric dust grains due to variable asymmetric charging. Observational evidence of electrical forces acting significantly on small solids is present for both the modern solar system in Saturn's rings and the ancient solar system in chondritic meteorites. It is likely that grain-grain coagulation rates are affected by the distribution of charges on small grains. Plasma particle impacts and photoelectric effects can provide the charges.

It appears that some charging is inevitable and that plasma grain interactions need to be evaluated to determine the size of the effect on coagulation rates. We apply the results of our previous charging work to models of the protoplanetary nebula. It is expected that the protoplanetary nebula is weakly ionized except in certain instances and locations such as: solar flares in the interior, ultraviolet radiation at the outer boundary, and during enhanced luminosity of the star.

Since the grains we study are non-conducting and show strong dipole moments in flowing plasma, we modify the geometric cross sections to include the effects of flowing plasma on non-conducting grains with plasma mediated shielding. This paper provides results showing how plasma flow affects the processes involved in charging the grains--total charge and charge distribution. We calculate the modifications to the cross sections and subsequent changes in the coagulation rates. The control mechanism of surface traps on surface charge behavior in alumina-filled epoxy composites.

To investigate the role surface traps play in the charge injection and transfer behavior of alumina-filled epoxy composites, surface traps with different trap levels are introduced by different surface modification methods which include dielectric barrier discharges plasma, direct fluorination, and Cr 2 O 3 coating. The resulting surface physicochemical characteristics of experimental samples were observed using atomic force microscopy, scanning electron microscopy and fourier transform infrared spectroscopy.

The surface potential under dc voltage was detected and the trap level distribution was measured. The results suggest that the surface morphology of the experimental samples differs dramatically after treatment with different surface modification methods.

Different surface trap distributions directly determine the charge injection and transfer property along the surface. Shallow traps with trap level of 1. The Cr 2 O 3 coating can introduce a large number of deep traps with energy levels ranging from 1.

These can prevent charge injection through the reversed electric field formed by intensive trapped charges in the Cr 2 O 3 coatings. Trajectory effects in multiply charged ion- surface interactions. Ar ions of 4. By selecting Ar projectiles having a large ionization potential and by using a large scattering angle only ions scattered at the first atomic layer of the surface were detected.

Scattered ion energy spectra show peaks of single scattering and double scattering of the Ar projectile ions from one or two surface Au atoms, and the distribution attributed to double collisions splits into two peaks when the scattering plane coincides with a crystallographic plane. Simulations with a MARLOWE code allowed for interpretation of the structure in the double collision peak by in-plane and zig-zag double collisions.

Differences in the relative peak heights between the experiment and a MARLOWE simulation were partly explained by different neutralization probabilities with varying trajectories. Yield changes with increasing charge states show interesting possibilities for future experiments with highly charged ions.

Work functions and surface charges at metallic facet edges. The electronic charge densities and work functions at sharp metallic facet edges are determined from ab initio calculations, combined with macroscopic averaging techniques. In particular, we examine how two different work functions coexist at close range near edges between inequivalent facets.

The surface ionic relaxation at facet edges is shown to influence appreciably the local electrostatic potential in the vacuum. Various edges between Al and Al facets are studied, as well as between Na facets. We also develop a model of electronic surface dipoles, which accounts for the surface charge transfer between inequivalent facets, and which allows us to predict the influence of the shape and size of a macroscopic crystal on its work functions.

Nonlinear periodic waves in dusty plasma with variable dust charge. Using the reductive perturbation method, we present a theory of nonlinear periodic waves, viz. It is found that the frequency of the dust acoustic cnoidal wave increases with its amplitude. The dust charge fluctuations are found to affect the characteristics of the cnoidal waves.

The pH dependent surface charging and points of zero charge. The pristine points of zero charge PZC and isoelectric points IEP of metal oxides and IEP of other materials from the recent literature, and a few older results overlooked in previous searches are summarized.

Colloid Interface Sci. The field has been very active, but most PZC and IEP are reported for materials, which are very well-documented already silica, alumina, titania, iron oxides. Their IEP were not reported in older studies. All rights reserved.

Charge state distributions from highly charged ions channeled at a metal surface. The vast majority of the experimental work in the field of multicharged ion- surface interactions, to date, has focused on x-ray and particularly on electron emission. These experiments include measurements of the total electron yield, the emission statistics of the electrons, and, most of all, the electron energy distributions.

So far, little attention has been paid to the fate of the multicharged projectile ions after the scattering. To our knowledge, the only measurement of the charge state distribution of the scattered ions is the pioneering experiment of de Zwart et al.

This suggests that a certain fraction of the inner-shell vacancies survives the entire collision event, and decays via autoionization on the outgoing path. Since the projectiles scattered in the neutral charge state could not be detected in the experiment of de Zwart et al. In our present experiment, we focus on the scattered projectiles, measuring both the final charge state and the total scattering angle with a single 2D position sensitive detector PSD.

This method gives us the number of positive, as well as neutral and negative, scattered ions, thus allowing us to extract absolute charge state fractions. Using a well-prepared single Au crystal and a grazing incidence geometry, we were able to observe surface channeling along the [] channels. Adsorption of charged albumin subdomains on a graphite surface. We find that the presence of charges affects somewhat the initial adsorption stage on the electrostatically neutral surface , but not the final one.

Thus, we recover the result that a monolayer of aminoacids is eventually formed, with a rough parallelism of distant strands to optimize both the intramolecular and the surface interactions. This feature is consistent with the adsorption on the hydrophobic surface being driven by dispersion forces only, and with the "soft" nature of albumin. The enhanced hydration of the final adsorption state due to the delocalized charges of the side groups is also discussed in comparison with similar results of the neutralized subdomains.

Electron capture by highly charged ions from surfaces and gases. In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Possible explanations are discussed. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected.

The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu -1 , charge -selected and then decelerated down to 5 eVu -1 for interaction with an argon gas target. For the investigation of electron capture from surfaces , highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu -1 , charge -selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes.

Surface characterization of polymethylmetacrylate bombarded by charged water droplets. The electrospray droplet impact EDI , in which the charged electrospray water droplets are introduced in vacuum, accelerated, and allowed to impact the sample, is applied to polymethylmetacrylate PMMA. The secondary ions generated were measured by an orthogonal time-of-flight mass spectrometer. This is due to the fact that the proton affinities of fragments formed from PMMA are smaller than those from acetic acid contained in the charged droplet.

The x-ray photoelectron spectroscopy spectra of PMMA irradiated by water droplets did not change with prolonged cluster irradiation, i. Sorption—bioavailability nexus of arsenic and cadmium in variable-charge soils. The adsorption of As and Cd was examined using a number of allophanic and non-allophanic soils which vary in their charge components.

The effect of pH and ageing on the bioavailability of As and Cd was examined using spiked soils in a plant growth experiment. The effect of phosphate P -induced mobility of As on its bioavailability was examined using a naturally contaminated sheep dip soil. The results indicated that the adsorption of both As and Cd varied amongst the soils, and the difference in Cd adsorption is attributed to the difference in surface charge.

An increase in soil pH increased net negative charge by an average of The bioavailability of As and Cd decreased by 3. Phosphate addition increased the mobility and bioavailability of As by 4. However, the net effect of P on As phytoavailability depends on the extent of P-induced As mobilization in soils and P-induced competition for As uptake by roots.

The results demonstrate the nexus between sorption and bioavailability of As and Cd in soils, indicating that the effects of. Bolan, Nanthi, E-mail: Nanthi. Bolan unisa. Okinawa RYS colloids in Japan. The VAS colloids exhibited a negative surface charge with a high pH dependency, whereas the RYS colloids exhibited a negative surface charge with less pH dependency.

The soil colloids were applied as colloidal suspensions to cm-long saturated sand columns packed Explanation of the surface peak in charge integrated LEIS spectra. Low energy ion scattering is very surface sensitive if scattered ions are analyzed. By time-of-flight TOF techniques, also neutral and charge integrated spectra ions plus neutrals can be obtained, which yield information about deeper layers.

In the literature, the observation of a more or less pronounced surface peak was reported for charge integrated spectra, the intensity of the surface peak being higher at low energies and for heavy projectiles. Aiming at a more profound physical understanding of this surface peak, we performed TOF-experiments and computer simulations for He projectiles and a copper target.

Experiments were done in the range keV for a scattering angle of deg. At low energies, a pronounced surface peak was observed, which fades away at higher energies. This peak is quantitatively reproduced by the simulation, and corresponds to scattering from approx 2 atomic Adsorption of cations onto positively charged surface mesopores.

Uwe Neue developed a theoretical treatment to account for the adsorption of ions on mesopores of packing materials the walls of which are bonded to ionic ligands but left this work unfinished. We elaborated upon this treatment and refined it, based on the equivalence that he suggested between charged surface particles and a membrane that separates two ionic solutions but is impermeable to one specification.

He had written that the electro-chemical potentials in both ionic solutions are equal Donnan equilibrium. The equilibrium between the surface and the pore concentrations is accounted for by an homogeneous electrostatically modified Langmuir EML isotherm model. The theoretical results provide the quantitative difference between the ionic strength, the pH, and the concentrations of all the ions in the pores and in the bulk eluent.

These theoretical results are in good agreement with experimental results published previously and explain them. Variable valve timing in a homogenous charge compression ignition engine. The present invention relates generally to the field of homogenous charge compression ignition engines, in which fuel is injected when the cylinder piston is relatively close to the bottom dead center position for its compression stroke. The fuel mixes with air in the cylinder during the compression stroke to create a relatively lean homogeneous mixture that preferably ignites when the piston is relatively close to the top dead center position.

However, if the ignition event occurs either earlier or later than desired, lowered performance, engine misfire, or even engine damage, can result. Monolayer phosphorene has attracted much attention owing to its extraordinary electronic, optical, and structural properties. Rationally tuning the electrical transport characteristics of monolayer phosphorene is essential to its applications in electronic and optoelectronic devices.

Herein, we study the electronic transport behaviors of monolayer phosphorene with surface charge transfer doping of electrophilic molecules, including 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane F4TCNQ , NO2, and MoO3, using density functional theory combined with the nonequilibrium Green's function formalism.

F4TCNQ shows optimal performance in enhancing the p-type conductance of monolayer phosphorene. Static electronic properties indicate that the enhancement is originated from the charge transfer between adsorbed molecule and phosphorene layer. Dynamic transport behaviors demonstrate that additional channels for hole transport in host monolayer phosphorene were generated upon the adsorption of molecule. Our work unveils the great potential of surface charge transfer doping in tuning the electronic properties of monolayer phosphorene and is of significance to its application in high-performance devices.

Surface charges promote nonspecific nanoparticle adhesion to stiffer membranes. This letter establishes the manner in which the electric double layer induced by the surface charges of the plasma membrane PM enhances the nonspecific adhesion NSA of a metal nanoparticle NP to stiffer PMs i. The NSA is characterized by the physical attachment of the NP to the membrane and occurs when the decrease in the surface energy or any other mechanism associated with the attachment process provides the energy for bending the membrane.

Such an attachment does not involve receptor-ligand interactions that characterize the specific membrane-NP adhesion. Here, we demonstrate that a significant decrease in the electrostatic energy caused by the NP-attachment-induced destruction of the charged -membrane-electrolyte interface is responsible for providing the additional energy needed for bending the membrane during the NP adhesion to stiffer membranes.

A smaller salt concentration and a larger membrane charge density augment this effect, which can help to design drug delivery to cells with stiffer membranes due to pathological conditions, fabricate NPs with biomimetic cholesterol-rich lipid bilayer encapsulation, etc. Experimental surface charge density of the Si -2x1H surface. We report a three-dimensional charge density refinement from x-ray diffraction intensities of the Si 2x1H surface.

By paying careful attention to parameterizing the bulk Si bonding, we are able to locate the hydrogen atoms at the surface , which could not be done previously. In addition, we Electrical manipulation of oligonucleotides grafted to charged surfaces. The electrical manipulation of short DNA molecules on surfaces offers novel functionalities with fascinating possibilities in the field of bio-interfaces. Here we present systematic investigations of the electrical interactions which govern the structure of oligonucleotides on charged gold surfaces.

Successively, we address influences of the applied field strength, the role of DC electrode potentials, in particular for polycrystalline surfaces , as well as screening effects of the surrounding electrolyte solution. Data obtained for single and double stranded DNA exhibit differences which can be attributed to the dissimilar flexibility of the different molecular conformations.

A comparison of the experimental results with a basic model shows how the alignment of the molecules adjusts according to a balance between electrically induced ordering and stochastic thermal motions. The presented conclusions are expected to be of general relevance for the behaviour of polyelectrolytes exposed to localized electric fields at interfaces. Ion association at discretely- charged dielectric interfaces: Giant charge inversion [Dielectric response controlled ion association at physically heterogeneous surfaces : Giant charge reversal.

Wang, Zhi -Yong [Chongqing Univ. Giant charge reversal has been identified for the first time by Monte Carlo simulation for a discretely charged surface in contact with a trivalent electrolyte solution. It takes place regardless of the surface charge density under study and the monovalent salt. In stark contrast to earlier predictions based on the 2-dimensional Wigner crystal model to describe strong correlation of counterions at the macroion surface , we find that giant charge reversal reflects an intricate interplay of ionic volume effects, electrostatic correlations, surface charge heterogeneity, and the dielectric response of the confined fluids.

While the novel phenomenon is yet to be confirmed with experiment, the simulation results appear in excellent agreement with a wide range of existing observations in the subregime of charge inversion. Lastly, our findings may have far-reaching implications to understanding complex electrochemical phenomena entailing ionic fluids under dielectric confinements. Renormalization in charged colloids: non-monotonic behaviour with the surface charge. The static structure factor S q is measured for a set of deionized latex dispersions with different numbers of ionizable surface groups per particle and similar diameters.

For a given volume fraction, the height of the main peak of S q , which is a direct measure of the spatial ordering of latex particles, does not increase monotonically with the number of ionizable groups. This behaviour cannot be described using the classical renormalization scheme based on the cell model. We analyse our experimental data using a renormalization model based on the jellium approximation, which predicts the weakening of the spatial order for moderate and large particle charges.

Full Text Available The present work reports a rapid, simple and efficient one-step synthesis and detailed characterisation of stable aqueous colloids of gold nanoparticles AuNPs coated with unmodified poly ethyleneglycol PEG molecules of different molecular weights and surface charges. The surface enhanced Raman scattering SERS signal does not depend on the length of the PEG molecular chain enveloping the AuNPs, and the stability of the colloid is not affected by the addition of concentrated salt solution 0.

Interannual variability caused by the El Nino-Southern Oscillation in the eastern tropical Pacific Ocean ETP is analogous to seasonal variability of comparable magnitude. Climatological spatial patterns and seasonal variability of physical variables that may affect the ETP ecosystem are presented and discussed. Surface temperature, surface salinity, mixed layer depth, thermocline depth, thermocline strength, and surface dynamic height were derived from bathythermograph, hydrocast, and High-resolution atomic force microscopy is used to map the surface charge on the basal planes of kaolinite nanoparticles in an ambient solution of variable pH and NaCl or CaCl 2 concentration.

Using DLVO theory with charge regulation, we determine from the measured force-distance curves the surface charge distribution on both the silica-like and the gibbsite-like basal plane of the kaolinite particles. We observe that both basal planes do carry charge that varies with pH and salt concentration. The silica facet was found to be negatively charged at pH 4 and above, whereas the gibbsite facet is positively charged at pH below 7 and negatively charged at pH above 7.

Investigations in CaCl 2 at pH 6 show that the surface charge on the gibbsite facet increases for concentration up to 10 mM CaCl 2 and starts to decrease upon further increasing the salt concentration to 50 mM. Atomic resolution imaging and density functional theory calculations corroborate these observations. Phenomena of charged particles transport in variable magnetic fields.

This present work is dedicated to the study of the dynamical phenomena for the transport of ions in the presence of variable magnetic fields in front of the Jupiter wave shock. We obtain the spectrum of the accelerated ions and we study the conditions of acceleration by solving the transport equation in the planetocentric system. We discuss the theoretical results obtained and make a comparison with the experimental parameters in the region of acceleration behind the Jupiter wave shock.

Surface -confined electroactive molecules for multistate charge storage information. Bi-stable molecular systems with potential for applications in binary memory devices are raising great interest for device miniaturization.

Particular appealing are those systems that operate with electrical inputs since they are compatible with existing electronic technologies. The processing of higher memory densities in these devices could be accomplished by increasing the number of memory states in each cell, although this strategy has not been much explored yet.

Here we highlight the recent advances devoted to the fabrication of charge -storage molecular surface -confined devices exhibiting multiple states. Mainly, this goal has been realized immobilizing a variety or a combination of electroactive molecules on a surface , although alternative approaches employing non-electroactive systems have also been described. Undoubtedly, the use of molecules with chemically tunable properties and nanoscale dimensions are raising great hopes for the devices of the future in which molecules can bring new perspectives such as multistability.

Previous observations suggested that Ceres has active, but possibly sporadic, water outgassing as well as possibly varying spectral characteristics over a timescale of months. Our analysis has placed an upper limit on the possible temporal albedo variation on Ceres.

The continuous sperm production throughout the activity season allows these liolaemids to mate at any time when females ovulate, representing a selective advantage to deal with the short activity season and the adversities of the cold environment they inhabit.

Gene-environment interaction and male reproductive function. As genetic factors can hardly explain the changes taking place during short time spans, environmental and lifestyle-related factors have been suggested as the causes of time-related deterioration of male reproductive function.

However, considering the strong heterogeneity of male fecundity between and within populations, genetic variants might be important determinants of the individual susceptibility to the adverse effects of environment or lifestyle. Although the possible mechanisms of such interplay in relation to the reproductive system are largely unknown, some recent studies have indicated that specific genotypes may confer a larger risk of male reproductive disorders following certain exposures.

This paper presents a critical review of animal and human evidence on how genes may modify environmental effects on male reproductive function. Some examples have been found that support this mechanism, but the number of studies is still limited. This type of interaction studies may improve our understanding of normal physiology and help us to identify the risk factors to male reproductive malfunction. We also shortly discuss other aspects of gene-environment interaction specifically associated with the issue of reproduction , namely environmental and lifestyle factors as the cause of sperm DNA damage.

It remains to be investigated to what extent such genetic changes, by natural conception or through the use of assisted reproductive techniques, are transmitted to the next generation, thereby causing increased morbidity in the offspring. Reproductive costs in terrestrial male vertebrates: insights from bird studies. Reproduction requires resources that cannot be allocated to other functions resulting in direct reproductive costs i.

In wild vertebrates, direct reproductive costs have been widely described in females, but their occurrence in males remains to be explored. To fill this gap, we gathered 53 studies on 48 species testing direct reproductive costs in male vertebrates. More precisely for this third question, it is expected that fast species i. Our findings tend to support this hypothesis. Finally, we pointed out the potential confounding effects that should be accounted for when investigating reproductive costs in males and strongly encourage the investigation of such costs in more clades to understand to what extent our results are relevant for other vertebrates.

Diabetes mellitus induced impairment of male reproductive functions: a review. Diabetes mellitus DM represents one of the greatest threats to human health all over the world. The incidence of DM is rising rapidly also including children and young persons of reproductive age. Diabetes has been associated with reproductive impairment in both men and women. Diabetes may affect male reproductive functions at multiple levels as a result of its effects on the endocrine control of spermatogenesis, steroidogenesis, sperm maturation, impairment of penile erection and ejaculation.

A large number of studies both on diabetic men and experimental diabetic animals have been published on the impact of DM on male reproductive functions during the past few years but many of them have conflicting results. The present review summarizes the research finding of a large number of research papers on the reproductive functions especially on hypothalmo-pituitary-gonadal axis, spermatogenesis, histopathology of testis, synthesis and secretion of testosterone, sperm quality, ejaculatory function and fertility both in diabetic men and experimental diabetic animals.

Antidiabetic therapies and male reproductive function: where do we stand? Diabetes mellitus has been increasing at alarming rates in recent years, thus jeopardizing human health worldwide. Several antidiabetic drugs have been introduced in the market to manage glycemic levels, and proven effective in avoiding, minimizing or preventing the appearance or development of diabetes mellitus-related complications.

However, and despite the established association between such pathology and male reproductive dysfunction, the influence of these therapeutic interventions on such topics have been scarcely explored. Importantly, this pathology may contribute toward the global decline in male fertility, giving the increasing preponderance of diabetes mellitus in young men at their reproductive age.

Therefore, it is mandatory that the reproductive health of diabetic individuals is maintained during the antidiabetic treatment. With this in mind, we have gathered the available information and made a critical analysis regarding the effects of several antidiabetic drugs on male reproductive function. Unlike insulin, which has a clear and fundamental role on male reproductive function, the other antidiabetic therapies' effects at this level seem incoherent. In fact, studies are highly controversial possibly due to the different experimental study approaches, which, in our opinion, suggests caution when it comes to prescribing such drugs to young diabetic patients.

Overall, much is still to be determined and further studies are needed to clarify the safety of these antidiabetic strategies on male reproductive system. Aspects such as the effects of insulin levels variations, consequent of insulin therapy, as well as what will be the impact of the side effect hypoglycemia, common to several therapeutic strategies discussed, on the male reproductive system are still to be addressed. Reproductive toxicity: Male and female reproductive systems as targets for chemical injury.

On the basis of current knowledge of reproductive biology and toxicology, it is apparent that chemicals affecting reproduction may elicit their effects at a number of sites in both the male and the female reproductive system. This multiplicity of targets is attributable to the dynamic nature of the reproductive system, in which the hypothalamic-pituitary-gonadal axis is controlled by precise positive and negative feedback mechanisms among its components.

Interference by a xenobiotic at any level in either the male or the female reproductive system may ultimately impair hypothalamic or pituitary function. The reproductive system is a complex one that requires local and circulating hormones for control. This brief review illustrates a system for characterizing the mechanism of action of reproductive toxicants, as well as for defining the sites available for disruption of reproduction.

Unfortunately, at present, data addressing the actual vulnerability of reproduction are sorely lacking. However, when experiments have been conducted and combined with epidemiologic data or clinical observation, it has been possible to demonstrate impairment of reproductive processes by xenobiotics.

The role of environmental exposure to xenobiotics in the increase in infertility that has been observed remains to be defined. Ageing and inflammation in the male reproductive tract. Ageing is usually characterised by a mild chronic proinflammatory state. Despite the tight association between both processes, the phenomenon has recently been termed inflammageing.

Inflammation in the male reproductive tract is frequently linked with bacterial or virus infections but also with a broad range of noninfectious processes. Prostatitis, epididymitis and orchitis, among others, can lead to infertility. However, in spite of the inflammation theory of disease, chronic inflammation in male urogenital system does not always cause symptoms.

With advancing age, inflammatory processes are commonly observed in the male reproductive tract. Nevertheless, the incidence of inflammation in reproductive organs and ducts varies greatly among elderly men. Inflammageing is considered a predictor of pathogenesis and the development of age-related diseases.

This article briefly summarises the current state of knowledge on inflammageing in the male reproductive tract. Yet, the precise aetiology of inflammageing in the male urogenital system, and its potential contribution not only to infertility but most importantly to adverse health outcomes remains almost unknown.

Developmental stress increases reproductive success in male zebra finches. There is increasing evidence that exposure to stress during development can have sustained effects on animal phenotype and performance across life-history stages.

For example, developmental stress has been shown to decrease the quality of sexually selected traits e. However, animals exposed to developmental stress may compensate for poor quality sexually selected traits by pursuing alternative reproductive tactics. Here, we examine the effects of developmental stress on adult male reproductive investment and success in the zebra finch Taeniopygia guttata.

We tested the hypothesis that males exposed to developmental stress sire fewer offspring through extra-pair copulations EPCs , but invest more in parental care. To test this hypothesis, we fed nestlings corticosterone CORT; the dominant avian stress hormone during the nestling period and measured their adult reproductive success using common garden breeding experiments. We found that nestlings reared by CORT-fed fathers received more parental care compared with nestlings reared by control fathers.

Consequently, males fed CORT during development reared nestlings in better condition compared with control males. Contrary to the prediction that developmental stress decreases male reproductive success, we found that CORT-fed males also sired more offspring and were less likely to rear non-genetic offspring compared with control males , and thus had greater overall reproductive success.

These data are the first to demonstrate that developmental stress can have a positive effect on fitness via changes in reproductive success and provide support for an adaptive role of developmental stress in shaping animal phenotype. Endocrine control of epigenetic mechanisms in male reproduction. Endocrine control of reproduction is very well known and has been echoed by many research groups. However, recent developments point to the ability of toxic endocrine disrupting chemicals EDC to alter epigenetic information of the gametes which gets transferred to the developing embryo and affects the immediate reproductive outcome or even persists transgenerationally.

These epigenetic aberrations contribute to the ensuing pathophysiology of reproductive disorders. Investigations of the female in cases of poor reproductive outcome have been the main strategy towards diagnosis. However, despite the male partner contributing half of his genome to the progeny, thorough investigations in the male have been ignored.

Environmental pollutants are all pervading and are encountered in our day-to-day life. Many of these pollutants have potential to disrupt the endocrine system. Here, we discuss how the male gametes spermatozoa are susceptible to a myriad of epigenetic insults inflicted by exposure to endocrine disruptors and how important is the contribution of the epigenetic marks of the spermatozoa in healthy reproduction. We advocate that sperm epigenetics should be considered as a significant contributor to reproductive health and should be researched further and be subsequently included in routine diagnostic workup in cases of poor reproductive outcome.

The transcriptome of Lutzomyia longipalpis Diptera: Psychodidae male reproductive organs. It has been suggested that genes involved in the reproductive biology of insect disease vectors are potential targets for future alternative methods of control. Little is known about the molecular biology of reproduction in phlebotomine sand flies and there is no information available concerning genes that are expressed in male reproductive organs of Lutzomyia longipalpis, the main vector of American visceral leishmaniasis and a species complex.

Gene ontology analysis identified subsets of genes involved in biological processes such as protein biosynthesis and DNA replication, which are probably associated with spermatogenesis. A number of non-redundant sequences were also identified as putative male reproductive gland proteins mRGPs , also known as male accessory gland protein genes Acps. The transcriptome analysis of L.

It has allowed the identification of genes potentially involved in spermatogenesis as well as putative mRGPs sequences, which have been studied in many insect species because of their effects on female post-mating behavior and physiology and their potential role in sexual selection and speciation. These data open a number of new avenues for further research in the molecular and evolutionary reproductive biology of sand flies. Background It has been suggested that genes involved in the reproductive biology of insect disease vectors are potential targets for future alternative methods of control.

Conclusions The transcriptome analysis of L. Gene expression changes in male accessory glands during ageing are accompanied by reproductive decline in Drosophila melanogaster. Senescence is accompanied by loss of reproductive functions. Here, we studied reproductive ageing in Drosophila melanogaster males and asked whether the expected decline in male reproductive success is due to diminished functionality of the male accessory gland AG.

The male AG produces the majority of seminal fluid proteins SFPs transferred to the female at mating. SFPs induce female postmating changes and are key to male reproductive success. Simultaneously, we also measured male reproductive success in postmating traits mediated by transfer of these five SFPs. We found a decreased in male SFP gene expression with advancing age and an accompanying decline in male postmating success. Hence, male reproductive senescence is associated with a decline in functionality of the male AG.

While overall individual SFP genes decreased in expression, our results point towards the idea that the composition of an ejaculate might change with male age as the rate of change was variable for those five genes. Exploring the human seminal plasma proteome: an unexplored gold mine of biomarker for male infertility and male reproduction disorder.

The human seminal fluid is a complex body fluid. It is not known how many proteins are expressed in the seminal plasma; however in analog with the blood it is possible up to 10, proteins are expressed in the seminal plasma. The human seminal fluid is a rich source of potential biomarkers for male infertility and reproduction disorder. In this review, the ongoing list of proteins identified from the human seminal fluid was collected.

Finally, the biomarker identified in different male reproductive system disorder was investigated using proteomics platforms so far. In this study, an attempt was made to update the human seminal plasma proteome database. Our finding showed that human seminal plasma studies used to date seem to have converged on a set of proteins that are repeatedly identified in many studies and that represent only a small fraction of the entire human seminal plasma proteome.

Fine structure of the male reproductive system and reproductive behavior of Lutzomyia longipalpis sandflies Diptera: Psychodidae: Phlebotominae. The male reproductive system of insects can have several tissues responsible for the secretion of seminal fluid proteins SFPs , such as testes, accessory glands, seminal vesicles, ejaculatory duct and ejaculatory bulb. The SFPs are transferred during mating and can induce several physiological and behavioral changes in females, such as increase in oviposition and decrease in sexual receptivity after copulation.

The phlebotomine Lutzomyia longipalpis is the main vector of visceral leishmaniasis. Despite its medical importance, little is known about its reproductive biology. Here we present morphological aspects of the male L. The male L. It follows an ejaculatory duct with an ejaculatory pump a large bulb enveloped by muscles and associated to tracheas. The terminal endings of the vasa deferentia are inserted into the seminal vesicle by invaginations of the seminal vesicle wall, which is composed by a single layer of gland cells, with well-developed endoplasmic reticulum profiles and secretion granules.

Our data suggest that the seminal vesicle acts both as a spermatozoa reservoir and as an accessory gland. Mating experiments support this hypothesis, revealing a decrease in mating frequency after copulation that indicates the effect of putative SFPs. Ultrastructural features of the L. Behavioral observations revealed a reduction in mating frequency of copulated females. Together with transcriptome analyses from male sandfly reproductive organs identifying ESTs encoding orthologs of SFPs, these data indicate the presence of putative L.

Background The male reproductive system of insects can have several tissues responsible for the secretion of seminal fluid proteins SFPs , such as testes, accessory glands, seminal vesicles, ejaculatory duct and ejaculatory bulb. Results The male L. Conclusion Ultrastructural features of the L. Heat stress affects male reproduction in a parasitoid wasp. In insects, reproductive success and survival are affected by temperature.

Reproduction is more sensitive than other physiological traits. While the effects of heat stress on females are well known, the effects on males are less clear. Hymenopteran parasitoids are valuable for studying the consequences of heat stress on male reproduction. In these species, through arrhenotoquous parthenogenesis, the sex ratio of the offspring is directly dependent on the sperm stock acquired by females during copulation.

In the course of ageing, the sperm stock of sub-fertile males increases but never reaches the level of control males. The physiological mechanisms are as yet unknown. The relationship between temperature, sperm stock and sex ratio should be taken into account in the management of parasitoids for integrated pest management. Male Xenopus laevis frogs have been observed to clasp other males in a sustained, amplectant position, the purpose of which is unknown.

We examined three possible hypotheses for this counter-intuitive behavior: 1 clasping males fail to discriminate the sex of the frogs they clasp; 2 male-male clasping is an aggressive or dominant behavior; or 3 that males clasp other males to gain proximity to breeding events and possibly engage in sperm competition.

Our data, gathered through a series of behavioral experiments in the laboratory, refute the first two hypotheses. We found that males did not clasp indiscriminately, but showed a sex preference, with most males preferentially clasping a female, but a proportion preferentially clasping another male. However, those males did gain proximity to oviposition by continued male-male clasping in the presence of the female.

Thus, our findings are consistent with, but cannot confirm, the third hypothesis of male-male clasping as an alternative reproductive tactic. No effects of MRI scan on male reproduction hormones. Magnetic resonance imaging MRI is increasing around the world and the possible adverse effects on reproductive health of electromagnetic fields EMFs in MRI are not previously studied. A prospective randomized balanced cross-over study using a head scan in real MRI with whole-body transmitting coil and sham MRI among 24 healthy male volunteers was conducted.

Serum-blood samples of inhibin B, testosterone, prolactine, thyreotropine, luteinizing hormone, follicle stimulating hormone, sex-hormone binding globuline and estradiol were taken before and after the different scans. Neither immediately after, nor after 11 days were there seen any differences in the hormone levels comparing real and sham MRI.

The lack of effects of EMF on male reproductive hormones should be reassuring to the public and especially for men examined in MRI. Adverse effects on other endpoints than male reproduction or possible chronic effect of multiple MRI scans have not been investigated in this study. Characterization of Reproductive Dormancy in Male Drosophila melanogaster. Insects are known to respond to seasonal and adverse environmental changes by entering dormancy, also known as diapause. In some insect species, including Drosophila melanogaster, dormancy occurs in the adult organism and postpones reproduction.

This adult dormancy has been studied in female flies where it is characterized by arrested development of ovaries, altered nutrient stores, lowered metabolism, increased stress and immune resistance and drastically extended lifespan.

Male dormancy, however, has not been investigated in D. Over 3 weeks of diapause we see a dynamic increase in stored carbohydrates and an initial increase and then a decrease in lipids. We also note an up-regulated expression of genes involved in metabolism, stress responses and innate immunity. In summary, our study shows that male D. However, our data suggest that dormant male flies deplete stored nutrients faster than females, studied earlier, and that males take longer to recover reproductive capacity after reintroduction to non-diapause conditions.

The evolution of mating signals is closely linked to sexual selection. Acoustic ornaments are often used as secondary sexual traits that signal the quality of the signaller. Here we show that song performance reflects age and reproductive success in the rock sparrow Petronia petronia. In an Alpine population in south-east France, we recorded the songs of males and assessed their genetic breeding success by microsatellite analysis. In addition to temporal and spectral song features, we also analysed for the first time whether the sound pressure level of bird song reflects reproductive success.

Males with higher breeding success sang at a lower rate and with a higher maximum frequency. We found also that older males gained more extra-pair young and had a higher overall breeding success, although they also differed almost significantly by having a higher loss of paternity in their own nests. Older males could be distinguished from yearlings by singing at lower rate and higher amplitudes. Our findings suggest that song rate may be used as a signal of age and together with song pitch as a signal of reproductive success in this species.

Alternatively, younger and less successful males might try to compensate their inferior status by increased song rates and lower pitch. Independent of age and quality, high-amplitude songs correlated with paternity loss in the own nest, suggesting that in this species song amplitude is not an indicator of male quality but high-intensity songs may be rather a response to unfaithful social mates.

Reproductive inefficiency in male black-footed ferrets Mustela nigripes. The black-footed ferret Mustela nigripes , once considered extinct, has benefited from captive breeding and subsequent reintroduction into native habitat. However, many males considered to be prime-breeding age years old fail to sire offspring. The present study was conducted to determine the incidence and etiology of male reproductive failure in and These data indicate that combined behavioral and physiologic factors, but not overall sperm quality, influence reproductive performance in male black-footed ferrets managed in captivity.

Zoo Biol , Copyright Wiley-Liss, Inc. Bioinformatics for spermatogenesis: annotation of male reproduction based on proteomics. Proteomics strategies have been widely used in the field of male reproduction , both in basic and clinical research.

Bioinformatics methods are indispensable in proteomics-based studies and are used for data presentation, database construction and functional annotation. In the present review, we focus on the functional annotation of gene lists obtained through qualitative or quantitative methods, summarizing the common and male reproduction specialized proteomics databases. We introduce several integrated tools used to find the hidden biological significance from the data obtained.

We further describe in detail the information on male reproduction derived from Gene Ontology analyses, pathway analyses and biomedical analyses. We provide an overview of bioinformatics annotations in spermatogenesis, from gene function to biological function and from biological function to clinical application. On the basis of recently published proteomics studies and associated data, we show that bioinformatics methods help us to discover drug targets for sperm motility and to scan for cancer-testis genes.

In addition, we summarize the online resources relevant to male reproduction research for the exploration of the regulation of spermatogenesis. The sexual health needs of young males have been largely ignored in the field of reproductive health. Until recently, the health care needs of females have received the vast majority of attention from public health professionals and organizations with services focused on the prevention of teen pregnancy, sexually transmitted infections, and….

Chonopeltis australis Crustacea male reproductive system morphology; sperm transfer and review of reproduction in Branchiura. The morphology of the male reproductive system as well as sperm transfer in Branchiura has been described for Dolops ranarum and Argulus japonicus.

In this study, the reproductive system and accessory structures are described for male Chonopeltis australis using histology, light microscopy, and scanning electron microscopy. For the first time, we describe sperm transfer by means of a spermatophore in this genus.

The internal and external morphology and mechanism of sperm transfer is compared with other Branchiura, where it has been described. The morphology of the reproductive system of C. A revision of the definition of Branchiura with respect to reproduction is provided.

Condition-dependent female preference for male genitalia length is based on male reproductive tactics. There is extensive morphological variation of male genitalia across animals with internal fertilization, even among closely related species. Most studies attempting to explain this extraordinary diversity have focused on processes that occur post-copula e.

Only a few studies have focused on the pre-copula process of female preference. In addition, the extent to which this variation could be associated with the use of different reproductive tactics has yet to be explored. Here, we show that female preference for male genitalia length in two livebearing fishes depends on the type of reproductive tactic of the males being evaluated as well as the body condition of the female. In a species where all males coax females to acquire matings courters , females preferred males with short genitalia.

In a species with genetically influenced alternative reproductive tactics courter males that only court and produce courter sons, sneaker males that use the coercive tactic of sneak chase and produce sneaker sons , female preference depended on an interaction between male tactic and female condition: females in good condition preferred courter males with short genitalia, and sneaker males with long genitalia.

Our results suggest that female preference for male traits favourable to their sons may be an important factor contributing to the diversification of male genitalia. Despite the contrasting selection for genitalia length that our female preference tests suggest, we found no significant differences in genitalia length between coaxing courters and coercive sneakers males.

Our study represents a starting point to more clearly understand the role of alternative reproductive tactics and variation in female mate preference in the evolution of male genitalia. Environmental risk factors and male fertility and reproduction. Several environmental substances and pesticides exert a direct, cytotoxic effect on male germ cells. However, an increasing concern has been raised by compounds that may act through more subtle mechanisms, for example, specific pesticides that are potentially capable of modulating or disrupting the endocrine system.

Overall, exposure to pesticides with endocrine-disrupting potential raise a particular concern for male fertility because of the possible occurrence of both effects at low concentrations and additive interactions with other environmental risk factors. Delayed reproductive problems deserve special attention, since experimental data consistently indicate a high vulnerability in the developing male reproductive system. Epidemiologic studies have confirmed an increased risk of conception delay associated with occupational exposure to pesticides.

Moreover, an increased risk of spontaneous abortion has been noted among wives of exposed workers. Sexual behavior, reproductive physiology and sperm competition in male mammals. Sperm competition involves competition between the gametes of two or more males of a species for fertilization of a given set of ova. Sperm competition is widespread among mammals, as in many other groups of vertebrates.

Effects of sexual selection, via sperm competition, upon the evolution of reproductive physiology and behavior are much better understood in invertebrates and especially in insects than is the case for mammals. However, if the reproductive organs of male mammals are viewed as an integrated system for production and delivery of spermatozoa and accessory glandular secretions to females, then it is logical to assume that sperm competition might influence the evolution of all parts of the system, as well as associated physiological mechanisms e.

Here we analyze and review relationships between mating systems, relative testes sizes and sperm morphology, phallic morphology, circulating testosterone levels and sexual behavior in male mammals. The organization of the developing male rodent brain is profoundly influenced by endogenous steroids, most notably estrogen.

This process may be disrupted by estrogenic endocrine disrupting compounds EDCs resulting in altered sex behavior and the capacity to attract a mate in adulthood. Exposure to DPN suppressed male reproductive behavior and attractiveness in a dose dependent manner.

Sexual performance was impaired by GEN but not attractiveness. In addition to suppressing reproductive behavior and attractiveness, EB exposure significantly lowered the testis to body weight ratio, and circulating testosterone levels. DPN and GEN exposure only impaired behavior, suggesting that disrupted androgen secretion does not underlie the impairment. Thyroid hormone actions on male reproductive system of teleost fish. Thyroid hormones THs play important roles in the regulation of many biological processes of vertebrates, such as growth, metabolism, morphogenesis and reproduction.

An increasing number of studies have been focused on the involvement of THs in the male reproductive system of vertebrates, in particular of fish. Therefore, this mini-review aims to summarize the main findings on THs role in male reproductive system of fish, focusing on sex differentiation, testicular development and spermatogenesis.

The existing data in the literature have demonstrated that THs exert their roles at the different levels of the hypothalamic-pituitary-gonadal HPG axis. In general a positive correlation has been shown between THs and fish reproductive status; where THs are associated with testicular development, growth and maturation. Recently, the molecular mechanisms underlying the role of THs in spermatogenesis have been unraveled in zebrafish testis.

THs promote germ cell proliferation and differentiation by increasing a stimulatory growth factor of spermatogenesis produced by Sertoli cells. In addition, THs enhanced the gonadotropin-induced androgen release in zebrafish testis. Next to their functions in the adult testis, THs are involved in the gonadal sex differentiation through modulating sex-related gene expression, and testicular development via regulation of Sertoli cell proliferation.

In conclusion, this mini-review showed that THs modulate the male reproductive system during the different life stages of fish. The physiological and molecular mechanisms showed a link between the thyroid and reproduction , suggesting a possibly co-evolution and interdependence of these two systems. A link between hypothyroidism, obesity and male reproduction. Hypothyroidism is a condition in which the serum levels of thyroid hormones are below that necessary to carry out physiological functions in the body.

Hypothyroidism is related to obesity as an increase in body weight gain is seen in hypothyroid patients. Moreover, an inverse correlation between free thyroxine values and body mass index has been reported. Leptin, a polypeptide hormone produced by adipocytes, was originally thought to be an antiobesity hormone due its anorexic effects on hypothalamic appetite regulation.

However, nowadays it is known that leptin conveys information about the nutritional status to the brain being considered a crucial endocrine factor for regulating several physiological processes including reproduction.

Since the identification of thyroid hormone and leptin receptors on the testes, these hormones are being recognized as having important roles in male reproductive functions. A clear link exists among thyroid hormones, leptin and reproduction.

Both hormones can negatively affect spermatogenesis and consequently may cause male infertility. Therefore, the goal of this review is to highlight the relationship of such hormones in the reproductive system. Analgesic use in pregnancy and male reproductive development. Purpose of review Male reproductive disorders are common and increasing in incidence in many countries.

Environmental factors including pharmaceuticals have been implicated in the development of these disorders. This review aims to summarise the emerging epidemiological and experimental evidence for a potential role of in-utero exposure to analgesics in the development of male reproductive disorders. Recent findings A number of epidemiological studies have demonstrated an association between in-utero exposure to analgesics and the development of cryptorchidism, although these findings are not consistent across all studies.

Where present, these associations primarily relate to exposure during the second trimester of pregnancy. In-vivo and in-vitro experimental studies have demonstrated variable effects of exposure to analgesics on Leydig cell function in the fetal testis of rodents, particularly in terms of testosterone production. These effects frequently involve exposures that are in excess of those to which humans are exposed. Investigation of the effects of analgesics on human fetal testis have also demonstrated effects on Leydig cell function.

Variation in species, model system, dosage and timing of exposure is likely to contribute to differences in the findings between studies. Summary There is increasing evidence for analgesic effects on the developing testis that have the potential to impair reproductive function.

However, the importance of these findings in relation to human-relevant exposures and the risk of male reproductive disorders remains unclear. Sexual selection, differences in reproductive success between individuals, continues beyond acquiring a mating partner and affects ejaculate size and composition sperm competition.

Sperm and seminal fluid have very different roles in sperm competition but both components encompass production costs for the male. Theoretical models predict that males should spend ejaculate components prudently and differently for sperm and seminal fluid but empirical evidence for independent variation of sperm number and seminal fluid volume is scarce. It is also largely unknown how sperm and seminal fluid variation affect future mating rate.

In bedbugs we developed a protocol to examine the role of seminal fluids in ejaculate allocation and its effect on future male mating rate. Using age-related changes in sperm and seminal fluid volume we estimated the lowest capacity at which mating activity started. We tested and confirmed this prediction empirically. Finally, the slightly faster replenishment of seminal fluid compared to sperm did not outweigh the faster decrease during mating.

Our results suggest that male mating rate can be constrained by the availability of seminal fluids. Our protocol might be applicable to a range of other organisms. We discuss the idea that economic considerations in sexual conflict research might benefit from distinguishing between costs and benefits that are ejaculate dose-dependent and those that are frequency-dependent on the mating rate per se. Effects of aging on the male reproductive system. The study aims to discuss the effects of aging on the male reproductive system.

A systematic review was performed using PubMed from to Aging is a natural process comprising of irreversible changes due to a myriad of endogenous and environmental factors at the level of all organs and systems. In modern life, as more couples choose to postpone having a child due to various socioeconomic reasons, research for understanding the effects of aging on the reproductive system has gained an increased importance. Paternal aging also causes genetic and epigenetic changes in spermatozoa, which impair male reproductive functions through their adverse effects on sperm quality and count as, well as, on sexual organs and the hypothalamic-pituitary-gonadal axis.

Hormone production, spermatogenesis, and testes undergo changes as a man ages. These small changes lead to decrease in both the quality and quantity of spermatozoa. The offspring of older fathers show high prevalence of genetic abnormalities, childhood cancers, and several neuropsychiatric disorders. In addition, the latest advances in assisted reproductive techniques give older men a chance to have a child even with poor semen parameters. Further studies should investigate the onset of gonadal senesce and its effects on aging men.

Reproductive toxicity of Roundup herbicide exposure in male albino rat. The incidence of infertility in human is on the increase and the use of Roundup herbicide and presence of its residues in foodstuff is a major concern. This study therefore aim to assess the effect of Roundup on the reproductive capacity of 32 adult male albino rats randomized into 4 groups of 8 rats per group orally exposed to Roundup at 3.

Serum level of reproductive hormone testosterone, luteinizing hormone LH , follicle stimulating hormone FSH and prolactin , oxidative stress indices in the testicular tissue, epididymal sperm morphology assessment and testicular histopathology of the rats were used as a diagnostic marker of reproductive dysfunction. Significant p reproductive hormones and oxidative stress markers assayed were observed in rats exposed to Roundup. Significant reductions p male gonad. Identity and transfer of male reproductive gland proteins of the dengue vector mosquito, Aedes aegypti: potential tools for control of female feeding and reproduction.

Sirot, Laura K. We sought to identify mRGPs of the yellow fever mosquito, Aedes aegypti, the primary vector of dengue and yellow fever viruses. Earlier studies with Ae. Using bioinformatic comparisons to Drosophila melanogaster accessory gland proteins and mass spectrometry of proteins from Ae.

Twenty-one of these proteins were found in the reproductive tract of mated females, but not of virgin females, suggesting that they are transferred from males to females during mating. Most of the putative mRGPs fall into the same protein classes as mRGPs in other organisms, although some appear to be evolving rapidly and lack identifiable homologs in Culex pipiens, Anopheles gambiae, and D.

Our results identify candidate male -derived molecules that may have an important influence on behavior, survival and reproduction of female mosquitoes. Environmental endocrine disruptors: Effects on the human male reproductive system. Incidences of altered development and neoplasia of male reproductive organs have increased during the last 50 years, as shown by epidemiological data. These data are associated with the increased presence of environmental chemicals, specifically "endocrine disruptors," that interfere with normal hormonal action.

Much research has gone into testing the effects of specific endocrine disrupting chemicals EDCs on the development of male reproductive organs and endocrine-related cancers in both in vitro and in vivo models. Efforts have been made to bridge the accruing laboratory findings with the epidemiological data to draw conclusions regarding the relationship between EDCs, altered development and carcinogenesis.

The ability of EDCs to predispose target fetal and adult tissues to neoplastic transformation is best explained under the framework of the tissue organization field theory of carcinogenesis TOFT , which posits that carcinogenesis is development gone awry.

Here, we focus on the available evidence, from both empirical and epidemiological studies, regarding the effects of EDCs on male reproductive development and carcinogenesis of endocrine target tissues. We also critique current research methodology utilized in the investigation of EDCs effects and outline what could possibly be done to address these obstacles moving forward.

Hybrid male sterility and genome-wide misexpression of male reproductive proteases. Hybrid male sterility is a common barrier to gene flow between species. Previous studies have posited a link between misregulation of spermatogenesis genes in interspecies hybrids and sterility. However, in the absence of fully fertile control hybrids, it is impossible to differentiate between misregulation associated with sterility vs.

Here, we differentiate between these two possibilities using a D. We identify genes uniquely misexpressed in sterile hybrid male reproductive tracts via RNA-seq. The sterile male hybrids had more misregulated and more over or under expressed genes relative to parental species than the fertile male hybrids. Proteases were the only gene ontology class overrepresented among uniquely misexpressed genes, with four located within a previously identified hybrid male sterility locus.

This result highlights the potential role of a previously unexplored class of genes in interspecific hybrid male sterility and speciation. Endocrine-disrupting chemicals generally function as steroid receptor signaling antagonists or agonists that influence development to promote adult-onset disease. Exposure to the endocrine disruptors during the initiation of male reproductive tract development interferes with the normal hormonal signaling and formation of male reproductive organs.

In particular, exposure to the endocrine disruptor vinclozolin promotes transgenerational transmission of adult-onset disease states such as male infertility, increased frequencies of tumors, prostate disease, kidney diseases, and immune abnormalities that develop as males age. An epigenetic change in the germ line would be involved in the transgenerational transmission of these induced phenotypes. Nevertheless, other studies have also reported transgenerational transmission of induced epigenetic changes, without altering the germ line.

Here we propose a nomenclature to help clarify both cases of transgenerational epigenetic transmission. An intrinsic epigenetic transgenerational process would require a germ-line involvement, a permanent alteration in the germ cell epigenome, and only one exposure to the environmental factor. An extrinsic epigenetic transgenerational process would involve an epigenetic alteration in a somatic tissue and require exposure at each generation to maintain the transgenerational phenotype.

Microminipigs are becoming increasingly attractive alternatives for various experimental applications, such as general toxicology studies, owing to their manageable size. However, there are limited studies on the male reproductive organs of microminipigs, particularly on the histological aspects of sexual maturity. To clarify the development of male reproductive organs, 35 male microminipigs, aged 0 to 12 months, were used in this study.

Histological and histomorphological evaluation was performed based on spermatogenic development, measurement of tubular structure in testes and epididymides, and histological progress of accessory glands. In addition, spontaneous testicular changes were quantitatively assessed.

Histologically, male microminipigs sexually matured around 4. Spontaneous testicular changes occurred in all the animals investigated. It is preferable to use sexually mature animals in toxicology studies; therefore, the information obtained by the present study will be helpful for future toxicity evaluations in microminipigs. Male reproductive strategy explains spatiotemporal segregation in brown bears.

Spatiotemporal segregation is often explained by the risk for offspring predation or by differences in physiology, predation risk vulnerability or competitive abilities related to size dimorphism. Most large carnivores are size dimorphic and offspring predation is often intraspecific and related to nonparental infanticide NPI.

NPI can be a foraging strategy, a strategy to reduce competition, or a male reproductive strategy. Spatiotemporal segregation is widespread among large carnivores, but its nature remains poorly understood. To test these hypotheses, we quantified spatiotemporal segregation among adult males , lone adult females and females with cubs-of-the-year, based on GPS-relocation data — and resource selection functions in a Scandinavian population. We found that spatiotemporal segregation was strongest between females with cubs-of-the-year and adult males during the mating season.

During the mating season, females with cubs-of-the-year selected their resources, in contrast to adult males , in less rugged landscapes in relative close proximity to certain human-related variables, and in more open habitat types. After the mating season, females with cubs-of-the-year markedly shifted their resource selection towards a pattern more similar to that of their conspecifics.

No strong spatiotemporal segregation was apparent between females with cubs-of-the-year and conspecifics during the mating and the postmating. Industrial use of aniline is increasing worldwide with production estimated to surpass 5. Exposure to aniline occurs via air, diet, and water augmenting the risk of exposing a large number of individuals. This is of concern as recent studies implicate paracetamol as a disrupter of reproduction.

By contrast, paracetamol decreased levels of androgens likely through inhibition of CYP17A1 activity. We confirm that aniline in vivo is rapidly converted to paracetamol by the liver. Intrauterine exposure to aniline and paracetamol in environmental and pharmaceutical relevant doses resulted in shortening of the anogenital distance in mice, a sensitive marker of fetal androgen levels that in humans is associated with reproductive malformations and later life reproductive disorders.

In conclusion, our results provide evidence for a scenario where aniline, through its conversion into antiandrogenic paracetamol, impairs male reproductive development. For Permissions, please e-mail: journals. Effect of glyphosate on reproductive organs in male rat. Many studies have focused on reproductive toxicity on glyphosate-based herbicide, but few evidence exists to imply the male reproductive toxicity of glyphosate alone in vivo.

Immunohistochemistry of androgen receptor AR has no difference among all groups. As to testosterone, estradiol, progesterone and oxidative stress parameters, the level of them has no differences amidst all doses. Taken together, we conclude that glyphosate alone has low toxicity on male rats reproductive system. Sexual selection leads to a tenfold difference in reproductive success of alternative reproductive tactics in male Atlantic salmon.

The precocious maturation of some male Atlantic salmon Salmo salar L. Using genetic parentage analysis on anadromous and precocious potential spawners and their offspring, we quantified components of individual reproductive success of both tactics in a natural population. On average, precocious males produced 2. Body size increased reproductive success of anadromous males and tended to decrease precocious males ' reproductive success.

Although these results do not solve the coexistence of alternative reproductive tactics ARTs in Atlantic salmon, their inclusion in comprehensive models of lifetime reproductive success should shed light on the evolution of precocious maturation in Atlantic salmon and its effect on the selection of phenotypic traits. Gap junctional communication in the male reproductive system. Male fertility is a highly controlled process that allows proliferation, meiosis and differentiation of male germ cells in the testis, final maturation in the epididymis and also requires functional male accessory glands: seminal vesicles, prostate and corpus cavernosum.

In addition to classical endocrine and paracrine controls, mainly by gonadotropins LH and FSH and steroids, there is now strong evidence that all these processes are dependent upon the presence of homocellular or heterocellular junctions, including gap junctions and their specific connexins Cxs , between the different cell types that structure the male reproductive tract.

The present review is focused on the identification of Cxs, their distribution in the testis and in different structures of the male genital tract epididymis, seminal vesicle, prostate, corpus cavernosum , their crucial role in the control of spermatogenesis and their implication in the function of the male accessory glands, including functional smooth muscle tone.

Their potential dysfunctions in some testis spermatogenic arrest, seminoma and prostate benign hyperplasia, adenocarcinoma diseases and in the physiopathology of the human erectile function are also discussed. In laboratory male mice the effects of social hierarchy on hormonal and spermatogenic testicular function, accessory organs and testicular weights, sexual behaviour have been investigated using an experimental model of social hierarchy, which is characterised by a minimal size two male mice and 5 days period of social interactions.

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