Net Electric Charge Research Articles

Electrochemical Properties of Latosols with Different Mineralogies

ABSTRACT Studying the electrochemical behavior of colloidal particles is important for fertility management and soil conservation, since it enables the understanding of several physicochemical phenomena that occur in soils. The objective of this study was to determine the point of zero charge (PZC) and the electrochemical behavior of surface and subsurface samples of three Red-Yellow Latosols (Oxisols), with different mineralogical and textural characteristics, through potentiometric titration and ionic adsorption. The point of zero charge (PZC) and the electrochemical behavior were determined in samples from the A and B horizons of three Red-Yellow Latosols: very clayey kaolinitic (LVAcr), very clayey gibbsitic (LVAgr) and sandy loam kaolinitic (LVAcm). The analyses were conducted in soil samples with particle size smaller than 0.7 mm, with desaturation of aluminum (Al3+), and smaller than 2 mm, without desaturation. Solutions containing sodium (Na+) and nitrate (NO3 −) as indifferent electrolytes were used in all methods. The LVAgr, even with higher organic matter contents, had higher PZC, indicating the importance of mineralogical composition for this characteristic. Among the two kaolinitic soils, there was higher PZC in LVAcm, with lower organic matter content; however, both soils had higher PZC in the B horizon than in the A horizon. The net electrical charge estimated by the potentiometric titration method was equivalent to the net charge estimated by the ionic adsorption method for horizons A and B of LVAgr and LVAcm. At the same time, there was underestimation of the net negative charge by the potentiometric titration method for the A and B horizons of LVAcr.

Heterogeneity of Fecal Calprotectin Reflecting Generation of Neutrophil Extracellular Traps (NETs) in the Gut: New Immunoassays Are Available

Background: We aimed at obtaining more information on the structure of fecal calprotectin (CP) as a basis for establishing improved quantitative assays and detection of Neutrophil Extracellular Traps (NETs) in stools. Commercial fecal CP assays produce different results, probably due to differences in antibodies, extraction procedures, and standards used. In addition, the structure of fecal CP may be different from that in the standard so that rules for immunoassays are violated. We aimed at solving these problems by studying the structure of fecal CP and developing new antibodies and assay procedures including some for NETs in stools. Methods and Findings: Stool samples from children with abdominal symptoms were extracted by a conventional and a new procedure. Some extracts were run on anion exchange and size exclusion chromatography, and fractions were tested on ELISAs by use of ten new mouse monoclonal antibodies against the CP subunit S100A9. Hybrid ELISAs (named HELISA) were established using anti-DNA or anti-histones for coating of microwells, and enzyme labelled anti-CP was used for development. By ion exchange chromatography, five to ten fecal CP subfraction peaks differing in net electric charge were found, all of which contained the major chromatin components. The presence of DNA and histones followed calprotectin in the chromatographic fractions suggesting that NETs are generated in the gut lumen. The new CP monoclonals reacted very differently against the subfractions so that a mixture of them (called MiMo) must be used to obtain reliable assay values for fecal CP. A new method called FELISA was developed where standards and samples are applied directly in Nunc (Denmark) MaxiSorp plates, without any catching antibody. It takes advantage of the property of CP to bind strongly to the plastic in wells. This method has a higher sensitivity because it will detect CP molecules with only one antigenic epitope available. It will give more reliable estimates and more efficient selection of patients for complex diagnostic procedures. We also developed an alternative to the FELISA: a competitive ELISA where S100A9 coated in microwells will compete with CP in standards and samples for binding to a properly diluted HRP-anti-CP solution. In this method, the presence of other proteins in extraction or dilution buffers will not interfere. Using the HELISA, about 65% of the patients had detectable fecal NETs in concentrations between 150 and 1500 ng/mL; however, the values correlated poorly with CP values. Extraction of fecal samples with a simple buffer of TBS, and pH 5 with 5 mM EDTA, gave a yield of about 90%, while the yields of commercial kits are not specified or lie around 50%. A fecal CP standard will bring methods in accordance with the requirements for immunoassays that the structure of CP in the standard and sample must be the same. A mixture of fecal anion exchange fractions as a standard may be a solution to this problem. The principle worked in the first trial by giving the same values after storage of such a standard at 5C for four months. Conclusions: Fecal CP consists of at least five subfractions containing NETs or degradation products thereof. Commercial kits should not be accepted for clinical use unless it has been shown that they can detect all subfractions which may require the use of a mixture of monoclonals. The methods presented here can be used for such a quality control. The HELISA methods can be used for assays on NETs in stools and to study their possible pathogenic effects in the gut. Use of the FELISA and the S100A9 competitive method may give increased sensitivity, higher precision, and better selection of patients for more complex procedures.

2D Bifurcation diagram of capacitively coupled Josephson junctions in high-Tc superconductors

We study the nonlinear dynamics in an array capacitively coupled Josephson junctions with N=3 junctions. We consider the superconductor/ insulator/ superconductor, SIS, type junctions as a model for high temperature superconductors with layered structure. In this study, we introduce the 2D bifurcation diagrams for the Josephson junctions. First we show a current voltage characteristics (CVC) of Intrinsic Josephson Junctions (IJJs) with N=3 Junctions, then we show the breakpoint region,BPR (a region in which a net electric charge appear on superconducting layers, (S-layers), of junctions), in the CVC of the system, then we try to investigate the chaos in BPR region by the 2D bifurcation diagram of the system. We show the 2D bifurcation diagrams in two cases in which either the coupling factor, α or the β parameter which is related to dissipation, be variable. In the later case we showed there is a range of β parameter in which the chaotic region of BPR is disappeared, also we show that there is another range of β in which the BPR structure disappeared.

Stellar Rotating Black Holes

Both mass and charge are needed to create a rotating Black Hole as has been investigated in great mathematical detail by the Reissner-Nordstrom metric and the Kerr-Newman metric. It is their application to astronomical phenomena that they have stated difficulty with because astronomical objects have no net electric charge and that is what we are exploring. While the energy in the gravitational field of the mass of a Neutron Star alone cannot create a stationary Black Hole, together with the energy in the strong magnetic field created by a rotating Neutron Star a rotating Black Hole is formed. Black Holes are the portal to the next higher spatial dimension.

Proteome-pI 2.0: proteome isoelectric point database update.

Proteome-pI 2.0 is an update of an online database containing predicted isoelectric points and pKa dissociation constants of proteins and peptides. The isoelectric point—the pH at which a particular molecule carries no net electrical charge—is an important parameter for many analytical biochemistry and proteomics techniques. Additionally, it can be obtained directly from the pKa values of individual charged residues of the protein. The Proteome-pI 2.0 database includes data for over 61 million protein sequences from 20 115 proteomes (three to four times more than the previous release). The isoelectric point for proteins is predicted by 21 methods, whereas pKa values are inferred by one method. To facilitate bottom-up proteomics analysis, individual proteomes were digested in silico with the five most commonly used proteases (trypsin, chymotrypsin, trypsin + LysC, LysN, ArgC), and the peptides’ isoelectric point and molecular weights were calculated. The database enables the retrieval of virtual 2D-PAGE plots and customized fractions of a proteome based on the isoelectric point and molecular weight. In addition, isoelectric points for proteins in NCBI non-redundant (nr), UniProt, SwissProt, and Protein Data Bank are available in both CSV and FASTA formats. The database can be accessed at http://isoelectricpointdb2.org.

Theory for attenuation and dispersion of acoustic propagation through a muddy medium

Mud as a medium typically consists of clay particles, small silt particles (primarily quartz), and water. The clay particles lock together in what is called a card-house configuration, and the silt particles are held in suspension by the card house. The low frequency velocity of sound waves appears to be well-predicted by the Mallock-Wood theory that gives weighted averages of bulk compressibility and material density. At low frequencies, the attenuation is caused by the viscous dag of the water on the suspended silt particles, and the attenuation varies as the frequency squared. The deviation of the phase velocity from the low frequency limit at low frequencies is less well-understood but appears to vary as the frequency to the three-halfs. At higher frequencies, the dominant mechanism appears to be a relaxation mechanism associated with the card house. Each clay particle carries a net electrical charge and the resulting repulsion forces the clay particles to be spatially separated. However, the particles tend to stick together edge to face, and the van der Waals attraction between the clay particles tends to dominate over the electrostatic repulsion. However, the passage of a sound wave temporarily breaks some van der Waals bonds and they subsequently recombine as the acoustic pressure ebbs. The present paper seeks to quantify the effects of the relaxation processes. It is demonstrated that the latter leads to an attenuation that, at higher frequencies, varies nearly linearly with frequency. [Work supported by ONR.]

Molecular Functionalization of 2H-Phase MoS2 Nanosheets via an Electrolytic Route for Enhanced Catalytic Performance.

The molecular functionalization of two-dimensional MoS2 is of practical relevance with a view to, for example, facilitating its liquid-phase processing or enhancing its performance in target applications. While derivatization of metallic 1T-phase MoS2 nanosheets has been relatively well studied, progress involving their thermodynamically stable, 2H-phase counterpart has been more limited due to the lower chemical reactivity of the latter. Here, we report a simple electrolytic strategy to functionalize 2H-phase MoS2 nanosheets with molecular groups derived from organoiodides. Upon cathodic treatment of a pre-expanded MoS2 crystal in an electrolyte containing the organoiodide, water-dispersible nanosheets derivatized with acetic acid or aniline moieties (∼0.10 molecular groups inserted per surface sulfur atom) were obtained. Analysis of the functionalization process indicated it to be enabled by the external supply of electrons from the cathodic potential, although they could also be sourced from a proper reducing agent, as well as by the presence of intrinsic defects in the 2H-phase MoS2 lattice (e.g., sulfur vacancies), where the molecular groups can bind. The acetic acid-functionalized nanosheets were tested as a non-noble metal-based catalyst for nitroarene and organic dye reduction, which is of practical utility in environmental remediation and chemical synthesis, and exhibited a markedly enhanced activity, surpassing that of other (1T- or 2H-phase) MoS2 materials and most non-noble metal catalysts previously reported for this application. The reduction kinetics (reaction order) was seen to correlate with the net electric charge of the nitroarene/dye molecules, which was ascribed to the distinct abilities of the latter to diffuse to the catalyst surface. The functionalized MoS2 catalyst also worked efficiently at realistic (i.e., high) reactant concentrations, as well as with binary and ternary mixtures of the reactants, and could be immobilized on a polymeric scaffold to expedite its manipulation and reuse.

A Systematic Review of Piezoelectric Materials and Energy Harvesters for Industrial Applications.

In the last three decades, smart materials have become popular. The piezoelectric materials have shown key characteristics for engineering applications, such as in sensors and actuators for industrial use. Because of their excellent mechanical-to-electrical and vice versa energy conversion properties, piezoelectric materials with high piezoelectric charge and voltage coefficient have been tested in renewable energy applications. The fundamental component of the energy harvester is the piezoelectric material, which, when subjected to mechanical vibrations or applied stress, induces the displaced ions in the material and results in a net electric charge due to the dipole moment of the unit cell. This phenomenon builds an electric potential across the material. In this review article, a detailed study focused on the piezoelectric energy harvesters (PEH’s) is reported. In addition, the fundamental idea about piezoelectric materials, along with their modeling for various applications, are detailed systematically. Then a summary of previous studies based on PEH’s other applications is listed, considering the technical aspects and methodologies. A discussion has been provided as a critical review of current challenges in this field. As a result, this review can provide a guideline for the scholars who want to use PEH’s for their research.

Fluctuations and correlations of net baryon number, electric charge and strangeness in a background magnetic field

We present results on the second-order fluctuations of and correlations among net baryon number, electric charge and strangeness in (2+1)-flavor lattice QCD in the presence of a background magnetic field. Simulations are performed using the tree-level improved gauge action and the highly improved staggered quark (HISQ) action with a fixed scale approach ($a\simeq$ 0.117 fm). The light quark mass is set to be 1/10 of the physical strange quark mass and the corresponding pion mass is about 220 MeV at vanishing magnetic field. Simulations are performed on $32^3\times N_\tau$ lattices with 9 values of $N_\tau$ varying from 96 to 6 corresponding to temperatures ranging from zero up to 281 MeV. The magnetic field strength $eB$ is simulated with 15 different values up to $\sim$2.5 GeV$^2$ at each nonzero temperature. We find that quadratic fluctuations and correlations do not show any singular behavior at zero temperature in the current window of $eB$ while they develop peaked structures at nonzero temperatures as $eB$ grows. By comparing the electric charge-related fluctuations and correlations with hadron resonance gas model calculations and ideal gas limits we find that the changes in degrees of freedom start at lower temperatures in stronger magnetic fields. Significant effects induced by magnetic fields on the isospin symmetry and ratios of net baryon number and baryon-strangeness correlation to strangeness fluctuation are observed, which could be useful for probing the existence of a magnetic field in heavy-ion collision experiments.

Molecular dynamics study on membrane fouling by oppositely charged proteins

AbstractMembrane fouling continues to hamper the performance of membrane‐filtration processes. A challenge with macromolecular foulants like proteins is that macroscopic characterizations, like net electrical charge, may be poorly correlated with membrane fouling. This necessitates a molecular‐scale analysis of the local interactions. In this study, molecular dynamics simulations have been performed to understand the interactions between two similar‐sized proteins with opposite overall charges (namely, lysozyme and α‐lactalbumin) and a negative‐charged membrane. Surprisingly, the protein–membrane distances and adsorption probabilities of both proteins are similar. Compared with the positive‐charged lysozyme, the negative‐charged α‐lactalbumin exhibits (a) greater protein–membrane attractive interaction energy due to synergy among adsorption sites; (b) lower root‐mean‐squared deviations (RMSD); and (c) greater number of residues that show low root‐mean‐squared fluctuations (RMSF). These results indicate that local interactions are critical and thus highlight the pitfall of using the overall protein characteristics as predictors of membrane fouling.

QCD equation of state at finite chemical potentials for relativistic nuclear collisions

We review the equation of state of QCD matter at finite densities. We discuss the construction of the equation of state with net baryon number, electric charge, and strangeness using the results of lattice QCD simulations and hadron resonance gas models. Its application to the hydrodynamic analyses of relativistic nuclear collisions suggests that the interplay of multiple conserved charges is important in the quantitative understanding of the dense nuclear matter created at lower beam energies. Several different models of the QCD equation of state are discussed for comparison.

Proof That a Dominant Endmember Formula Can Always Be Written for a Mineral or a Crystal Structure

ABSTRACTAn endmember formula must be: (1) conformable with the crystal structure of the mineral, (2) electroneutral (i.e., not carry a net electric charge), and (3) irreducible [i.e., not capable of being factored into components that have the same bond topology (atomic arrangement) as that of the original formula]. The stoichiometry of an endmember formula must match the “stoichiometry” of the sites in the structure; for ease of expression, I denote such a formula here as a chemical endmember. In order for a chemical endmember to be a true endmember, the corresponding structure must obey the valence-sum rule of bond-valence theory. For most minerals, the chemical endmember and the (true) endmember are the same. However, where local order would lead to strong deviation from the valence-sum rule for some local arrangements, such arrangements cannot occur and the (true) endmember differs from the chemical endmember. I present heuristic and algebraic proofs that a specific chemical formula can always be represented by a corresponding dominant endmember formula. That dominant endmember may be derived by calculating the difference between the mineral formula considered and all of the possible endmember compositions; the endmember formula which is closest to the mineral formula considered is the dominant endmember.

Charge conservation and higher moments of charge fluctuations

Higher moments of distributions of net charge and baryon number in heavy-ion collisions have been proposed as signals of fundamental QCD phase transitions. In order to better understand background processes for these observables, models are presented which enable one to gauge the effects of local charge conservation, decays of resonances and clusters, Bose symmetrization, and volume fluctuations. Monte Carlo methods for generating samplings of particles consistent with local charge conservation are presented, and are followed by a review of simple analytic models involving a single type of charge with a constant experimental efficiency. The main model consists of thermal emission superimposed onto a simple parameterization of collective flow, known as a blast-wave, with emission being consistent with individual canonical ensembles. The spatial extent of local charge conservation is parameterized by the size and extent over which charge is conserved. The sensitivity of third and fourth order moments, skewness and kurtosis, to these parameters, and to beam energy and baryon density is explored. Comparisons with STAR data show that a significant part of the observed non-Poissonian fluctuations in net-proton fluctuations are explained by charge and baryon-number conservation, but that measurements of the STAR collaboration for fluctuations of net electric charge significantly differ from expectations of the models presented here.

QCD equation of state at finite densities for nuclear collisions

We construct the QCD equation of state at finite chemical potentials including net baryon, electric charge, and strangeness based on the results of lattice QCD simulations and the hadron resonance gas model. The situation of strangeness neutrality and a fixed charge-to-baryon ratio, which resembles that of heavy nuclei, is considered for the application to relativistic heavy-ion collisions. This increases the values of baryon chemical potential compared to the case of vanishing strangeness and electric charge chemical potentials, modifying the fireball trajectory in the phase diagram. We perform viscous hydrodynamic simulations and demonstrate the importance of multiple chemical potentials for identified particle production in heavy-ion collisions at the RHIC and SPS beam energy scan energies.

Charged charm stars

The study of the general properties and stability of charm stars with a net electric charge is performed within the MIT bag model framework. We consider two different models for the electric charge distribution and demonstrate that both imply stellar configurations with larger masses and that satisfy the equilibrium condition. The dynamical stability against radial oscillations is investigated. Our results demonstrate that the eigenfrequencies are modified by the presence of a net electric charge, but the instability, previously demonstrated for the electrically neutral case, is also present in charged charm stars.

Chemical freeze-out conditions from net-kaon fluctuations at RHIC

We compare the mean-over-variance ratio of the net-kaon distribution calculated within a state-of-the-art hadron resonance gas model to the latest experimental data from the Beam Energy Scan at RHIC by the STAR collaboration. Our analysis indicates that it is not possible to reproduce the experimental results using the freeze-out parameters from the existing combined fit of net-proton and net-electric charge mean-over-variance. The strange mesons need about 10-15 MeV higher temperatures than the light hadrons at the highest collision energies. In view of the ongoing lambda fluctuation measurements, we predict the net-lambda variance-over-mean at the light and strange chemical freeze-out parameters. We observe that the lambda fluctuations are sensitive to the difference in the freeze-out temperatures established in this analysis. Our results have implications for other phenomenological models in the field of relativistic heavy-ion collisions.

A supportive electrostatic model of the COVID-19 airborne transmission

A mechanism-oriented model is proposed here as a speculative but robust attempt to understand whether there might be any increased risk of electrostatically induced contamination, with relevant consequences from the epidemiological viewpoint. This could also be the case for the COVID-19 spreading because an amount of micro-sized droplet nuclei, often carrying net electric charge, are expected to be electro-dynamically involved in a physical process originated by the natural and unperceivable static electrification of human beings. The effects of the triboelectric charging have long been successfully tested because the phenomenon under examination is also implied in the genesis of the electrostatic discharge (ESD), a demanding key objective in the special context of electromagnetic compatibility (EMC). Therefore, the ultimate purpose of this technical paper is to provide valuable insights into infection control, building on what is already being done for maintaining static-safe environments. The stature of the applied model can be further appreciated because some currently observed climate-dependent and sex-linked different vulnerabilities to COVID-19 are critically examined by unique sound arguments. These ultimately focus attention on ambient relative humidity and worn shoes, the latter differing for typology, size and material, for their integrated control of the inadvertent human aptitude to buildup tribocharges. These would appear as a dreadful prerequisite for charge bearing droplets in the airborne state to be efficiently attracted/repelled according to the described electrostatic mechanism.

Nitrate Mobility in Variable-Charge Tropical Soils

ABSTRACT Nitrate (NO3 –-N) leaching in tropical soils, which are more weathered, is influenced by their mineralogical, physical, and chemical characteristics. Thus, the present study aimed to evaluate the effect of the variation of net electrical charge on the mobility of nitrate, applied as potassium nitrate (KNO3) or calcium nitrate (Ca(NO3)2), in samples from A and B horizons of three Red-Yellow Latosols (Oxisols), with different mineralogical and textural characteristics. Hydrochloric acid (HCl) or sodium hydroxide (NaOH) volumes were added to previously sterilized soil samples in order to condition five hydrogen potential (pH) values, obtaining different net electrical charges. The experiment was carried out with leaching columns under laboratory conditions. The soil columns were percolated with solutions of KNO3 or Ca(NO3)2 or water (control). An increase in positive net charges was significant and varied according to the soil and percolating solution; in general, it resulted in an increase of up to 50% in nitrate adsorption in some soils. Larger amounts of adsorbed nitrate were observed in the columns filled with the B horizon of the clayey gibbsitic Red-Yellow Latosol, showing adsorption of 85% for a positive net charge of 2 cmolc kg−1. Regarding kaolinitic soils, lower adsorption was observed in the medium-textured kaolinitic Red-Yellow Latosol, which had lower clay content and positive net charge. Application of Ca(NO3)2, as a percolating solution, increased nitrate adsorption compared to the application of KNO3. This effect may be attributed to the increase in positive net charge promoted by calcium (Ca2+), being more evident for the highest negative net charges.

Electrically charged strange stars with an interacting quark matter equation of state

The properties of electrically charged strange quark stars predicted by an interacting quark matter equation of state (EoS) based on cold and dense perturbative quantum chromodynamics (pQCD) are investigated. The stability of strange stars is analyzed considering different models for the electric charge distribution inside the star as well as for distinct values for the total electric charge. A comparison with the predictions derived using the MIT bag model is also presented. We show that the presence of a net electric charge inside strange stars implies in a larger maximum mass in comparison to their neutral counterparts. Moreover, we demonstrate that the pQCD EoS implies larger values for the maximum mass of charged strange stars, with very heavy charged stars being stable systems against radial oscillations. For an electric charge distribution given by $q(r) = \beta r^3$, the pQCD EoS implies unstable configurations for large values of the renormalization scale as well as for large values of $\beta$, in contrast to the MIT bag model predictions.

Low-density lipoprotein from active SLE patients is more atherogenic to endothelial cells than low-density lipoprotein from the same patients during remission.

SLE patients have an enhanced risk of atherosclerosis and cardiovascular disease. However, the increased prevalence of cardiovascular disease is not fully explained by traditional Framingham cardiovascular risk factors. Specific features of low-density lipoprotein (LDL) particles, other than plasma concentration, may induce accelerated atherosclerosis at early stages in these patients. Thus, we aimed to explore the impact of LDL from both active and inactive SLE patients on human aortic endothelial cells. Human aortic endothelial cells were stimulated with the same concentration of LDL particles isolated from pooled serum that was collected from 13 SLE patients during both active and inactive states. Gene expression and cell migration assays were performed. Circulating LDL particles obtained from healthy volunteers and SLE patients in both remission and flare states were comparable in terms of number, cholesterol and triglyceride content, and net electric charge. Stimulation of cells with LDL from active SLE patients induced the expression of vascular cell adhesion molecule 1 (∼2.0-fold, P < 0.05), monocyte chemoattractant protein 1 (∼2.0-fold, P < 0.05) and matrix metallopeptidase 2 (∼1.6-fold, P < 0.01) compared with cells stimulated with LDL from inactive SLE patients. Additionally, LDL extracted from active patients increased cell migration in a wound-healing assay (1.4-fold, P < 0.05). Our data show that, at the same LDL concentration, LDL from active SLE patients had increased proatherogenic effects on endothelial cells compared with LDL from the same patients when in an inactive or remission state.