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Soil pH is a critical parameter influencing numerous soil properties including nutrient cycling, microbial activity, inorganic carbon and metal speciation and criteria for classifying acid sulfate soils and soils with reactive aluminium (Podzols and Andosols). Accurate measurement of soil pH is essential for effective soil assessment, management and crop production. This review of soil pH focuses on techniques and challenges for measurement and utilises insights from a comprehensive global soil dataset (n = 655,336). Soil pH has a global average of 6.36 with considerable regional variability. A Random Forest model of the global dataset identified total carbonate content, rainfall, evaporation, clay and organic carbon content as key drivers of soil pH (R2 = 0.77, mean absolute error = 0.46 pH units). The advantages and limitations of various soil pH measurement methods (e.g., glass and solid‐state electrodes, colorimetric and spectrophotometric methods, infrared spectroscopy, remote sensing and specialised field assessment methods) are discussed. Care should be taken in choosing appropriate pH measurement techniques depending on the purpose of the measurement and nature of the soils. The use of electrolytes (e.g., CaCl2 and KCl) introduces variable changes in measured pH and, on average globally, pH measured in a 1:5 soil:0.01 M CaCl2 extract is ~0.7 pH units lower than that measured in a 1:5 soil suspension. Although the use of electrolytes can help stabilise pH measurements in low ionic strength soils, their use requires careful consideration, as they do not eliminate all seasonal variability (which may also be important to assess) and they can introduce large pH perturbations in sodic‐alkaline and acid sulfate soils. Varying soil‐to‐solution ratios have less influence on resultant pH values than electrolytes however the measurements at low soil‐to‐solution ratios (e.g., 1:1 soil:water) are preferable for accuracy. Perturbations from field pH conditions due to CO2 outgassing and oxidation are likely when wet soils, acid sulfate soils and/or sub‐soils are measured in the laboratory. These findings underscore the need for improved field measurement technology and further research on the measurement protocols to ensure accurate and reliable soil pH data, which are crucial for optimising agricultural practices and environmental management. [ABSTRACT FROM AUTHOR]

AimsThe study examined the prevalence and degree of lactate elevation in diabetic ketoacidosis, and explored which biochemical abnormalities predicted L-lactate levels.MethodsWe reviewed episodes of diabetic ketoacidosis from 79 diabetes patients (one episode per patient). Separate univariate linear regression models were specified to predict lactate level from each of nine biochemical variables. Significant predictors from the univariate models were included in a final multivariate linear regression model to predict lactate levels.ResultsMean (SD) lactate level was 3.05 (1.66) mmol/L; about 65% of patients had lactate levels >2 mmol/L. In the final multivariate linear regression model (R2  = 0.45), higher lactate levels were associated with greater hydrogen ion concentration (standardised β = .60, t = 4.16, p

The purpose of this review and commentary was to provide an historical and evidence-based account of organic acids and the biochemical and organic chemistry evidence for why cells do not produce metabolites that are acids. The scientific study of acids has a long history dating to the 16th and 17th centuries, and the definition of an acid was proposed in 1884 as a molecule that when in an aqueous solution releases a hydrogen ion (H+). There are three common ionizable functional groups for molecules classified as acids: 1) the carboxyl group, 2) the phosphoryl group and 3) the amine group. The propensity by which a cation will associate or dissociate with a negatively charged atom is quantified by the equilibrium constant (Keq) of the dissociation constant (Kd) of the ionization (Keq ​= ​Kd), which for lactic acid (HLa) vs. lactate (La-) is expressed as: Keq=Kd=[H+][La−][HLa]= 4 677.351 4 (ionic strength ​= ​0.01 Mol⋅L-1, T ​= ​25 ​°C). The negative log10 of the dissociation pKd reveals the pH at which half of the molecules are ionized, which for HLa ​= ​3.67. Thus, knowing the pKd and the pH of the solution at question will reveal the extent of the ionization vs. acidification of molecules that are classified as acids.

The purpose of this review and commentary was to provide an historical and evidence-based account of organic acids and the biochemical and organic chemistry evidence for why cells do not produce metabolites that are acids. The scientific study of acids has a long history dating to the 16th and 17th centuries, and the definition of an acid was proposed in 1884 as a molecule that when in an aqueous solution releases a hydrogen ion (Hþ). There are three common ionizable functional groups for molecules classified as acids: 1) the carboxyl group, 2) the phosphoryl group and 3) the amine group. The propensity by which a cation will associate or dissociate with a negatively charged atom is quantified by the equilibrium constant (Keq) of the dissociation constant (Kd) of the ionization (Keq = Kd), which for lactic acid (HLa) vs. lactate (La-) is expressed as: Keq = Kd = [HLa] [La] =[HLa] = 4 677.351 4 (ionic strength = 0.01 Mol-L-1, T = 25 °C). The negative log10 of the dissociation pKd reveals the pH at which half of the molecules are ionized, which for HLa = 3.67. Thus, knowing the pKd and the pH of the solution at question will reveal the extent of the ionization vs. acidification of molecules that are classified as acids. [ABSTRACT FROM AUTHOR]

We examined the possibility of measuring dissolved oxygen by using a potentiometric solid-state semiconductor sensor. Thin films of tin (IV) oxide (SnO2) are widely used in oxygen gas sensors. However, their ability to detect dissolved oxygen (DO) in solutions is still unknown. In this paper, we present a method for investigating the dissolved oxygen-sensing properties of SnO2 thin films in solutions by fabricating a SnO2-gate field-effect transistor (FET). A similarly structured hydrogen ion-sensitive silicon nitride (Si3N4)-gate FET was fabricated using the same method. The transfer characteristics and sensitivities were experimentally obtained and compared. The transfer characteristics of the FET show a shift in threshold voltage in response to a decrease in DO concentration. The SnO2-gate FET exhibited a sensitivity of 4 mV/ppm, whereas the Si3N4-gate FET showed no response to DO. Although the SnO2-gate FET responds to pH changes in the solution, this sensitivity issue can be eliminated by using a Si3N4-gate FET, which is capable of selectively sensing hydrogen ions without DO sensitivity. The experimental results indicate the promising properties of SnO2 thin films for multimodal sensing applications. [ABSTRACT FROM AUTHOR]

In this review, we discuss the mechanisms of generation of membrane-bound protons using different energy sources in model and natural systems. Analysis of these mechanisms revealed that all three types of reactions include the same principal stage, which is dissociation of electrically neutral Brønsted acids at the interface during transition from the hydrophobic phase to water with a low dielectric constant. Special attention is paid to the fact that in one of the analyzed model systems, membrane-bound protons provide energy for the reaction of ATP synthesis. Similar mechanism for the generation of membrane-bound protons has been found in natural membranes involved in oxidative phosphorylation, in particular, on the membranes of mitoplasts and mitochondria. The energy of oxidative reactions required for ATP synthesis, is stored at the intermediate stage not only in the form of transmembrane electrochemical potential of protons, but also and perhaps mostly, as protons attached to the inner mitochondrial membrane. The process of energy storage in mitochondria is linked to the transfer of protons that simultaneously perform two functions. Protons on the membrane surface carry free energy and, at the same time, act as substrates facilitating the movement of F1F0-ATP-synthase biological machine. [ABSTRACT FROM AUTHOR]

Abstract Negative photoconductivity effect has been observed in the Au/WO3 nanowire/Au devices in a high humidity environment, which might be attributed to the accumulation of H+ ions on the surface of WO3 nanowire. Under illumination with violet light (445 nm), the photo-excited holes can oxidize the adsorbed H2O molecules to produce H+ ions and O2, while the photo-excited electrons at the conduction band bottom do not have enough energy to reduce H+ ions. These H+ ions will accumulate on the surface of the hexagonalWO3 nanowire. They will capture mobile electrons and then reduce the concentration of carriers, which will result in a significant increase in the height of interface barrier and then a significant decrease in the conductance of the Au/h-WO3 nanowire/Au device. By adjusting the relative humidity, light intensity, or bias voltage, the concentration and distribution of H+ ions and then the conversion between positive and negative photoconductivity, as well as resistive switching properties, can be well regulated in this kind of devices.

Soils contaminated with crude oil collected from three sites in Delta State were analyzed using serial dilution and pour plate methods. The physicochemical characteristics of the soil were determined using standard methods. The mean heterotrophic bacteria count and the mean hydrocarbon utilizing bacteria count were also determined. Blood haemolysis, foaming activity, oil spreading techniques and emulsification assay was used to screen the microorganisms for biosurfactant production. The biosurfactant producing bacteria were selected and their effect on metal removal and growth kinetics was also determined. The pH of the contaminated soil samples ranged 4.82 to 5.62. The mineral elements such as potassium (k+) and sodium (Na+) ranged from 0.20 to 0.80 Meq/100g and 0.07 to 0.81 Meq/100g respectively. The heavy metal content such as zinc (Zn2+) and lead (Pb2+) ranged from 10.13 to 19.24 mg/kg and 19.24 to 49.63 mg/kg respectively. Organic carbon and THC ranged from 5.44 to 6.87 % and 2720.00 to 3110.00 mg/kg respectively. The mean heterotrophic bacteria and hydrocarbon utilizing bacteria ranges from 1.4 ± 0.4 x 106 to 1.6 ± 0.7 x 106 and 1.0 ± 0.2 x 106 to 1.2 ± 0.4 × 106 respectively in the soil samples. Bacteria isolated and identified from the three sites include Corynebacterium spp., Bacillus subtilis., Pseudomonas aeruginosa, Micrococcus varians, Streptococcus spp., Klebsiella spp. and Enterobacter spp. with Bacillus subtilis and Pseudomonas aeruginosa having the highest prevalence and among these isolates only Corynebacterium spp., Bacillus subtilis., Pseudomonas aeruginosa and Micrococcus varians showed positive result for the production of biosurfactant. Bacillus subtilis had the highest metal removal capacity of 29.44% of 100 ppm of lead. Corynebacterium spp. and Bacillus subtilis had an optimum growth at pH 8 and 7 respectively while Pseudomonas aeruginosa and Micrococcus varians has an optimum growth at pH. [ABSTRACT FROM AUTHOR]

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This study was designed to investigate the effect of β-alanine supplementation on sprint time during repeated sprint ability test and blood lactate and bicarbonate responses to the test. Eighteen male soccer players were randomly divided into two groups (β-alanine, n=9 (24.31±2.14 yrs) or placebo, n=9 (23.98±2.07)). We conducted a randomized, double-blind, parallel-group, placebo-controlled study in which participants ingested 4.8 g/day for four weeks of a β-alanine supplement or a placebo. Athletes completed seven repetitions of 30 m interspersed with 30 s recovery intervals. The test was performed before and after four weeks of supplementation. Blood samples were collected from each participant in both groups before and after the test, pre- and post-supplementation to measure lactate and bicarbonate levels. Data showed that the sixth and seventh repetitions were significantly faster after β-alanine supplementation than the placebo (sixth repetition: 3.74±0.04 s vs 3.91±0.09 s, seventh repetition: 3.91±0.07 s vs 4.12±0.14 s, p=0.001, p=0.002, respectively). Before supplementation, however, no differences existed between groups for any sprint time in all repetitions (p>0.05). Data revealed significantly higher lactate concentration in the β-alanine than the placebo after the finish of the test at both pre-supplementation (p=0.022), and post-supplementation (p=0.017). No differences noted between groups in bicarbonate at all measured points. In conclusion, β-alanine supplementation has a beneficial effect on repeated sprint performance in soccer players, probably due to effective vasodilatation mechanism. [ABSTRACT FROM AUTHOR]

Purpose: Monitoring the pH of IVF culture media is a good practice, but the required pH levels have been "arbitrarily" set. Assisted reproductive technology centers around the world are spending time and money on pH monitoring without any consensus to date. The objective of this narrative review was to evaluate the importance of pH monitoring during IVF, discover how the oocyte and embryo regulate their intracellular pH and try to determine the optimal pH to be applied. Methods: A narrative literature review was performed on publications in the PubMed database reporting on the impact of pH on cellular function, oocyte and embryo development, IVF outcomes and pathophysiology, or on physiological pH in the female reproductive tract. Results: Intracellular pH regulates many cellular processes such as meiotic spindle stability of the oocyte, cell division and differentiation, embryo enzymatic activities, and blastocoel formation. The internal pH of the human embryo is maintained by regulatory mechanisms (mainly Na+/H+ and HCO3−/Cl− exchangers) that can be exceeded, particularly in the oocyte and early-stage embryos. The opinion that the optimal pH for embryo culture is physiological pH is not correct since several physicochemical parameters specific to IVF culture conditions (temperature, medium composition, duration of culture, or implication of CO2) can modify the intracellular pH of the embryo and change its needs and adaptability. Conclusions: Because correct and stable extracellular pH is essential to embryo health and development, monitoring pH is imperative. However, there is a lack of clinical data on choosing the ideal pH for human IVF culture media. [ABSTRACT FROM AUTHOR]

Quantum theory is awash in multidimensional integrals that contain exponentials in the integration variables, their inverses, and inverse polynomials of those variables. The present paper introduces a means to reduce pairs of such integrals to one dimension when the integrand contains powers multiplied by an arbitrary function of xy/(x+y) multiplying various combinations of exponentials. In some cases these exponentials arise directly from transition-amplitudes involving products of plane waves, hydrogenic wave functions, and Yukawa and/or Coulomb potentials. In other cases these exponentials arise from Gaussian transforms of such functions.

To overcome the numerical difficulties inherent in the Maxwell–Boltzmann integral of the velocity-weighted cross section that gives the radiative attachment rate coefficient α R A for producing the negative hydrogen ion H − or its antimatter equivalent, the positive antihydrogen ion H ¯ + , we found the analytic form for this integral. This procedure is useful for temperatures below 700 K, the region for which the production of H ¯ + has potential use as an intermediate stage in the cooling of antihydrogen to ultra-cold (sub-mK) temperatures for spectroscopic studies and probing the gravitational interaction of the anti-atom. Our results, utilizing a 50-term explicitly correlated exponential wave function, confirm our prior numerical results.

Graphical abstract Highlights • Permeation across GO membranes for mixed solution was concerned. • Concentration and recovery of Cu2+ with GO membranes was investigated. • Inhibitory effect of hydrogen ion on the transport of copper ions was demonstrated. Abstract Graphene-based materials have many unique features including atomic thickness and well-defined nanochannels, making their great properties for filtration and separation. The removal of low-level heavy-metal ions (e.g. Cu2+) by graphene oxide sheets has been discussed to ascertain their adsorption capacity, but separation and recovery of massive copper ions with graphene oxide (GO) membranes remain to be further studied. Besides, the permeation across GO membranes involving different ions in the very same solution is rarely investigated. Hence, the permeation properties of GO membranes concerning single and mixed solutions of acid and salt were examined in this study, and inhibitory effect of hydrogen ion on the copper ions transport was observed. Expectedly, GO membranes perform obvious permeation rate differences to acid (i.e. H 2 SO 4 , HCl) and copper salts (i.e. CuSO 4 , CuCl 2) when they are tested individually. The diffusion coefficient of H+ is 16 times larger than that of Cu2+ when the anion is SO 4 2−, and twice in the case of Cl−. The differences are mainly determined by physical screening of the capillary channels in the film for ions with different hydration radii and the rapid migration of hydrogen ions in solution. Furthermore, Experiments were carried out using mixed solution of acid and copper salt with the same anion and concentration. It was shown that the existence of H+, whose own transmission decreased by only 1.6 times, reduced the penetration of Cu2+ by an order of magnitude in the same time interval. We supposed this remarkable inhibitory effect is associated with shrink of interlayer spacing and competitive adsorption of H+ against Cu2+ on the surface of GO membranes in mixed solution. The properties of GO membranes show great application prospects in separation and wastewater reuse. [ABSTRACT FROM AUTHOR]

Abstract: Objective: We hypothesized that CO2 and H+ stimulate capillaries and arterioles to produce local and conducted vasodilations required to coordinate the distribution of blood flow to contracting skeletal muscle fibers. Methods: CO2 and H+ independently and in combination were applied to 2A arterioles (first branch order from the 1A feed arteriole) and capillaries of the in situ, blood‐perfused hamster cremaster muscle. The resulting local and conducted vasodilations were measured. Results: H+ (pH: 7.2‐6.6) and CO2 (5% and 10%) applied to the vascular network induced 2A arteriolar vasodilations, while 15% CO2 produced vasoconstriction. Localized application of H+ produced 2A arteriolar vasodilation, while 15% CO2 resulted in a variable response. Simultaneous application of CO2 and H+ did not result in the predicted additive effects. Application of CO2 and H+ alone or combined on arterioles or capillaries did not induce a conducted response. Conclusions: CO2 and H+ produce arteriolar vasodilation but, critically, cannot stimulate the spread of vasodilation throughout the network, thus limiting their ability to coordinating blood flow to contracting skeletal muscle fibers. Given their potential for interaction, the importance of CO2 and H+ may lie in their ability to modify the effects of other vasodilators. [ABSTRACT FROM AUTHOR]

This paper details a laser beam delivery and pointing stabilization system designed for the Laser-Assisted Charge Exchange (LACE) experiment at the Spallation Neutron Source (SNS) accelerator. The UV (355 nm) laser beam of 140 mJ pulses at 10 Hz must be transported over 65 m through a retrofitted laser transport line in a high-radiation area of the accelerator, causing the alignment of the beam to jitter and drift significantly on timescales of 0.1–1 s and > 1 min, respectively, due to thermal effects and other disturbances. The laser pointing stabilization system is based on a novel technique which uses active feedback between CMOS cameras and a piezoelectric steering mirror controlled by feedback software to make corrections to the horizontal angle and vertical position of the laser beam at 10 Hz. Low frequency drift is easily controlled, and the long-term stability is limited by the amplitude of high frequency components of the spectrum near the Nyquist limit (5 Hz). With feedback turned on, the root-mean-square (RMS) deviations of the horizontal angle and vertical position over 20 min fell from 314 to 157 μ rad and 309 to 167 μ m , respectively, which is below the pulse-to-pulse jitter at 10 Hz of 189 μ rad RMS and 180 μ m RMS. [ABSTRACT FROM AUTHOR]

With the aim of quantifying the purely hydrological control on fast water quality dynamics, a modelling approach was used to identify the structure (and dynamic response characteristics or DRCs) of the relationship between rainfall and hydrogen ion (H+) load, with reference to rainfall to streamflow response. Unlike most hydrochemistry studies, the method used makes no a priori assumptions about the complexity of the dynamics (e.g., number of flow-paths), but instead uses objective statistical methods to define these (together with uncertainty analysis). The robust models identified are based on continuous-time transfer functions and demonstrate high simulation efficiency with a constrained uncertainty allowing hydrological interpretation of dominant flow-paths and behaviour of H+ load in four upland headwaters. Identified models demonstrated that the short-term dynamics in H+ concentration were closely associated with the streamflow response, suggesting a dominant hydrological control. The second-order structure identified for the rainfall to streamflow response was also seen as the optimal model for rainfall to H+ load, even given the very dynamic concentration response, possibly indicating the same two flow-paths being responsible for both integrated responses.

As part of a broader study of the environmental geochemistry behavior of vanadium (V), the release kinetics of V from the dissolution of natural vanadium titano-magnetite under environmentally relevant conditions was investigated. In both the acidic and basic domains, the V release rate was found to be proportional to fractional powers of hydrogen ion and dissolved oxygen activities. The dependence of the rate on dissolved oxygen can also be described in terms of the Langmuir adsorption model. The empirical rate equation is given by: r = k ′ α H + α Kα O 2 1 + Kα O 2 where, α = 0.099–0.265, k′ = 3.2 × 10 − 6 –1.7 × 10 − 5 , K = 2.7 × 10 4 –3.9 × 10 4 mol/L in acid solution (pH 4.1), and α = − 0.494 − (− 0.527), k′ = 2.0 × 10 4 –2.5 × 10 − 11 , and K = 4.1 × 10 3 –6.5 × 10 3 mol/L in basic solution (pH 8.8) at 20°C. Based on the effect of temperature on the release rate of V, the activation energies of minerals at pH 8.8 were determined to be 148–235 kJ/mol, suggesting that the dissolution of vanadium titano-magnetite is a surface-controlled process. The presence of Na + , Ca 2 + , Mg 2 + , K + , NO 3 − , Cl − , SO 4 2 − and CO 3 2 − was found to accelerate the V release rates. This study improves the understanding of both the V pollution risk in some mine areas and the fate of V in the environment. [ABSTRACT FROM AUTHOR]

Using DEMETER and DMSP satellite data, the spatial distribution of hydrogen ion (H+) in local daytime has been compared and analyzed. At 840 km of DMSP height, the seasonal variations of H+ density is basically symmetric, with similar density values near to the magnetic equator at northern hemisphere in December and at southern hemisphere in June. But at DEMETER satellite height, the peak H+ density shows obvious enhancement at northern hemisphere in December solstice, while with approximate small values at both hemispheres in June. This spatial distribution feature is totally different with other ions such as O+ and He+ at the topside ionosphere. And also it influences the transition height in topside ionosphere, with lower transition height over northern hemisphere in December season at 10 - 20°N than those at equator and over southern hemisphere in June season. The solstitial asymmetry index (AI) of H+ at 670 km altitude gives the significant December season enhancement over northern hemisphere, which is typically reversed with electron density (Ne) and ion density (Ni) with large numbers over southern hemisphere in December season. Finally combining with the distribution of H atoms and neutral wind velocity in upper atmosphere, the forming mechanism and asymmetry feature of peak H+ density is discussed. It is illustrated that the upwelling movement at equatorial area and northward neutral wind play important roles in H+ peak drift in December season at DEMETER satellite altitude below the transition height where H+ is not the main composition in the local daytime in solar minimum years. [ABSTRACT FROM AUTHOR]

Short duration repeated maximal efforts are often used in swimming training to improve lactate tolerance, which gives swimmers the ability to maintain a high work rate for a longer period of time. The aim of the study was to examine the kinematics of swimming and its relation to the changes in blood acid-base status and potassium level. Seven collegiate swimmers, with at least 6 years of training experience, volunteered to participate in the study. The test consisted of 8 x 25 m front crawl performed with maximum effort. The rest period between repetitions was set to five seconds. Blood samples were taken from the fingertip at rest, after warm-up and in the 3rd minute after completion of the test. The swimming was recorded with a video recorder, for later analysis of time, velocity and technique (stroke index). Based on the swimming velocity results, the obtained curve can be divided into rapid decrease of velocity and relatively stable velocities. The breaking point of repetition in swimming velocity was assumed as the swimming velocity threshold and it was highly correlated with the decrease of the blood acid-base status (pH r=0.82, BE r=0.87, HCO3- r=0.76; p

La función principal y reguladora del sistema respiratorio es mantener las presiones normales de oxígeno y dióxido de carbono, así como la concentración de iones H+ o hidrogeniones, lo cual se consigue adecuando la ventilación pulmonar a las necesidades metabólicas orgánicas de consumo y producción de ambos gases, respectivamente. A pesar de las amplias variaciones en los requerimientos de captación de oxígeno y eliminación de dióxido de carbono, las presiones arteriales de ambos elementos se mantienen dentro de márgenes muy estrechos por una compleja regulación de la ventilación de los pulmones mediante determinados sistemas de control. Por tratarse de un tema muy complicado y disponerse ahora de nuevos conocimientos al respecto, se decidió describir en este breve artículo la organización morfofuncional general de los elementos que integran el sistema de control de la función respiratoria humana normal.The regulating main function of the breathing system is to maintain the normal oxygen and carbon dioxide pressures, as well as the H+ or hydrogen ions concentration, which is achieving adapting the lung ventilation to the organic metabolic needs of consumption and production of both gases, respectively. In spite of the wide variations in the requirements of oxygen intake and of carbon dioxide elimination, the arterial pressures of both elements remain within very narrow margins due to a complex regulation of the lungs ventilation by means of certain control systems. As it is a very complicated topic and as there are now new knowledge on this respect, it was decided to describe in this brief work the general morphological and functional organization of the elements that form the control system of the normal human breathing function.

"n "nBackgrounds and Objectives: Nitrate is a water contaminant that can cause health problems in human and animals, in addition to eutrophication of the water body. So, Nitrate-contaminated water may be treated by treatment systems. In this study, hydrogenotrophic denitrification using hydrogen produced by Fe0 as an electron donor to nitrate removal was evaluated to assess the feasibility of employing Fe0 in the biological nitrate treatment."nMaterials andMethods : Batch experiments were conducted using 250 ml amber bottles at 20-35oC under anoxic conditions. The nitrate concentration in each reactor was 20 mg N/L and triplicate samples were prepared for the following treatment: Fe0 plus cells, Fe0 only, and control. The effect of Fe+2 and temperature on nitrate reduction was evaluated."nResults : 97 percent of Nitrate was reduced within 2 day in a Fe0-cell reactor, while only 30% of the nitrate was abiotically reduced over 2 day at 30 oC. Fe+2, which is produced during anaerobic iron corrosion in the Fe0-cell system, might act as an electron donor for nitrate. Abiotic reduction and microbial reduction of nitrate was significantly affected by temperature conditions. The reduction rate decreased as the temperature deceased."nConclusion:This study demonstrated the potential applicability of employing Fe0 as a source of electrons for biological nitrate reduction. Use of Fe0 for microbial nitrate reduction can obviate the disadvantages associated with traditional biological denitrification that relies on the use of organic substrates or explosive hydrogen gas.

We studied air quality in a sub-mountain beech ecosystem in the Kremnické vrchy Mts., Central Slovakia. We chose the method of passive sampling. The amounts of airborne pollutants (H+ and O3) were determined at regular time intervals, covering the whole vegetation period, on four plots with different stocking. The original stand was subjected to two cuts with a purpose to simulate the phases of a common silvicultural process. The first research period (1999-2003) started 10 years after the first cutting, the second (2004-2006) was launched immediately after the second cut. Ten years after applying the first cut, the differences in the proton load input were getting smaller - with the dynamically changing crown canopy. The largest difference in proton load (H+ was found between plots C and I after the second intervention, when the correlation coefficient value was 0.15. The differences in proton load input between the plots were influenced by the cut, especially in the first three years after its application. No significant differences in ground level ozone concentrations between plots I (intensive cut), Me (medium intensive), Mo (moderate) and C (control) were revealed either after the first or after the second cutting intervention. Differences in ozone concentrations are not significant, and they indicate that the stocking density does not play an important role in association with ozone affecting the stands. The increase in ozone concentrations after the second intervention was evident on all plots - indicating the absence of connection with the individual phases of forest management process, but at the same time indicating the presence of climate change. In the studied sub-mountain beech ecosystem in the Kremnické vrchy Mts., an important role of episodes with high ozone concentrations is evident.

RESUMEN El entendimiento de los disturbios electrolíticos y ácido-base depende de la comprensión de los mecanismos fisiológicos que los regulan y de la interpretación de los cambios en el pH sanguíneo. Algunas enfermedades producen un patrón constante de pérdidas de fluidos y electrolitos con cambios predecibles en el volumen y la concentración. Además, uno o más de los componentes que los regulan pueden estar comprometidos, lo cual, puede resultar en desórdenes del estado ácido-base. Actualmente existen tres enfoques para la evaluación clínica del estado ácido-base: la ecuación de Henderson-Hasselbach, el modelo de iones fuertes y el modelo de iones fuertes simplificado, quedando a consideración del clínico su utilización. La manipulación de la diferencia entre cationes y aniones en la dieta (DCAD) es definida como los mili-equivalentes de (Na + K) - (Cl + S) por kilogramo (mEq/kg) de materia seca (MS) y tiene un impacto directo sobre el estado ácido-base, siendo el cloruro de amonio la sal con más poder acidificante y el sulfato de magnesio la sal aniónica más palatable, teniendo en cuenta que el pH urinario es una herramienta útil para evaluar el grado de acidosis metabólica impuesto por las sales aniónicas. Los valores de laboratorio interpretados por cualquier modelo son solo un paso en el análisis electrolítico y ácido-base del paciente. Para tomar decisiones racionales, se deben correlacionar estos valores con el cuadro clínico y el conocimiento de la bioquímica y fisiología subyacente, utilizando los importantes principios de la medicina, basada en la evidencia.SUMMARY Understanding the electrolyte and acid-base disorder depends on the comprehension of the physiological mechanisms which regulates them, and the interpretation of changes in blood pH. Some diseases produce a constant pattern of electrolyte and fluid loss with foreseeable changes in electrolyte concentration and fluid volume. Furthermore, one or more of the regulatory components may become compromised, resulting in disorders of the acid-base status. Currently there are three approaches to the clinical assessment of acid-base status: the Henderson-Hasselbach equation, the strong ion model and the simplified strong ion model, dependent its use on considerations of the professional. The manipulation of the dietary cation-anion difference (DCAD) is defined as the m-equivalents of (Na + K) - (Cl+S) by kilogram (mEq/kg) of dry matter (DM) It has a direct effect on the acid-base status, being ammonium chloride the most acidifying salt and magnesium sulfate the most palatable anionic salt, taking in count that urinary pH is a useful tool to assess the degree of metabolic acidosis imposed by the anionic salts. Laboratory values are just one step in an electrolyte and acid-base analysis of patient. To make rational decisions these values must be correlated with the clinical picture and the knowledge of the underlying biochemistry and physiology, using the important principles of evidence-based medicine.

The potential drop across the cell Δ v ∗ has profound influence on current density. [Display omitted] • The performance of a glucose fuel cell is investigated using a mathematical model. • The system of nonlinear equations are solved analytically for steady-state conditions. • As a function of various parameters, the model provides glucose and hydrogen concentration profiles across the cell. The performance of an enzymatic membrane-less and mediator-less glucose fuel cell is theoretically discussed. This paper solves a system of strongly nonlinear differential equations following Michaelis–Menten kinetics analytically. Simple approximate expressions for the concentration of glucose and hydrogen ions have been derived using a new analytical approach. Glucose concentration profiles are seen to drop throughout the cell. A careful study of the system parameters on concentration and current has been done. Sensitivity analysis has been carried out to understand the impact of each parameter on current. Satisfactory agreement is noted between the numerical results obtained through MATLAB and the results obtained by the new analytical approach. Tables and figures are presented to support the conclusions achieved. [ABSTRACT FROM AUTHOR]

Background: The hydrogen ion (H + ) mobilisation model has been previously shown to accurately describe blood bicarbonate (HCO 3 ) kinetics during haemodialysis (HD) when the dialysate bicarbonate concentration ([HCO 3 ]) is constant throughout the treatment. This study evaluated the ability of the H + mobilization model to describe blood HCO 3 kinetics during HD treatments with a time-dependent dialysate [HCO 3 ]., Methods: Data from a recent clinical study where blood [HCO 3 ] was measured at the beginning of and every hour during 4-h treatments in 20 chronic, thrice-weekly HD patients with a constant (Treatment A), decreasing (Treatment B) and increasing (Treatment C) dialysate [HCO 3 ] were evaluated. The H + mobilization model was used to determine the model parameter (H m ) that provided the best fit of the model to the clinical data using nonlinear regression. A total of 114 HD treatments provided individual estimates of H m ., Results: Mean ± standard deviation estimates of H m during Treatments A, B and C were 0.153 ± 0.069, 0.180 ± 0.109 and 0.205 ± 0.141 L/min (medians [interquartile ranges] were 0.145 [0.118,0.191], 0.159 [0.112,0.209], 0.169 [0.115,0.236] L/min), respectively; these estimates were not different from each other ( p  = 0.26). The sum of squared differences between the measured blood [HCO 3 ] and that predicted by the model were not different during Treatments A, B and C ( p  = 0.50), suggesting a similar degree of model fit to the data., Conclusions: This study supports the validity of the H + mobilization model to describe intradialysis blood HCO 3 kinetics during HD with a constant H m value when using a time-dependent dialysate [HCO 3 ].

Recently, a high-efficiency laser assisted hydrogen ion (H-) beam stripping was successfully carried out in the Spallation Neutron Source (SNS) accelerator. The experiment was not only an important step toward foil-less H- stripping for charge exchange injection, it also set up a first example of using megawatt ultraviolet (UV) laser source in an operational high power proton accelerator facility. This paper reports in detail the design, installation, and commissioning result of a macro-pulsed multi-megawatt UV laser system and laser beam transport line for the laser stripping experiment. [ABSTRACT FROM AUTHOR]

The emergence of quantum consciousness stems from dynamic flows of hydrogen ions in brain liquid. This liquid contains vast areas of the fourth phase of water with hexagonal packing of its molecules, the so-called exclusion zone (EZ) of water. The hydrogen ion motion on such hexagonal lattices shows as the hopping of the ions forward and the holes (vacant places) backward, caused by the Grotthuss mechanism. By supporting this motion using external infrasound sources, one may achieve the appearance of the superfluid state of the EZ water. Flows of the hydrogen ions are described by the modified Navier-Stokes equation. It, along with the continuity equation, yields the nonlinear Schrödinger equation, which describes the quantum effects of these flows, such as the tunneling at long distances or the interference on gap junctions. [ABSTRACT FROM AUTHOR]

Hv1 is a voltage-gated proton channel highly expressed in phagocytic cells, where it participates in the NADPH oxidasedependent respiratory burst. We have recently identified Hv1 as a novel renal channel, expressed in the renal medullary thick ascending limb that appears to importantly contribute to the pathogenesis of renal hypertensive injury in the Dahl salt-sensitive rat model. The purpose of this review is to describe the experimental approaches that we have undertaken to identify the source of excess reactive oxygen species production in the renal outer medulla of Dahl salt-sensitive rats and the resulting evidence that the voltage-gated proton channel Hv1 mediates augmented superoxide production and contributes to renal medullary oxidative stress and renal injury. In addition, we will attempt to point out areas of current controversy, as well as propose areas in which further experimental studies are likely to move the field forward. The content of the following review was presented as part of the Water and Electrolyte Homeostasis Section New Investigator Award talk at Experimental Biology 2014. [ABSTRACT FROM AUTHOR]