Predominant Anion Research Articles

Groundwater hydrochemical characteristics by districts area in Bulgaria

The aim of this study is to give a current result for the ion composition of groundwater from hypergenic zone of Bulgaria, for which chemical data for the major ions HCO3–, SO42–, Cl–, Ca2+, Mg2+, Na+ and K+ for the period 2015–2019 are used. The long-term annual average cation content in groundwater for individual districts in Bulgaria is: Ca2+>Mg2+>Na+>K+ or Mg2+>Ca2+>Na+>K+ for Pleven District and Ca2+>Na+>Mg2+>K+ for Burgas and Gabrovo districts. The anions are in the order HCO3–>SO42–>Cl– and HCO3–>Cl–>SO42– for the districts of Gabrovo, Dobrich, Varna, Burgas, Silistra and Razgrad. The predominant anion is bicarbonate, and of the cations, Mg2+ is predominant in Pleven District, while for the other districts, the predominant cation is Ca2+. The average TDS value is 229–1,051 mg/L. It is the lowest for Smolyan District and the highest for Pleven District. Predominantly groundwater is HCO3–-Ca2+-Mg2+ and HCO3–-Mg2+-Ca2+ for Pleven District. There are also deviations from these ratios, determined by differences in the mineral composition of the water-bearing medium, as well as by the influence of hydroclimatic conditions in different seasons.

Glutamate transporters are involved in direct inhibitory synaptic transmission in the vertebrate retina.

In the central nervous system of vertebrates, glutamate serves as the primary excitatory neurotransmitter. However, in the retina, glutamate released from photoreceptors causes hyperpolarization in post-synaptic ON-bipolar cells through a glutamate-gated chloride current, which seems paradoxical. Our research reveals that this current is modulated by two excitatory glutamate transporters, EAAT5b and EAAT7. In the zebrafish retina, these transporters are located at the dendritic tips of ON-bipolar cells and interact with all four types of cone photoreceptors. The absence of these transporters leads to a decrease in ON-bipolar cell responses, with eaat5b mutants being less severely affected than eaat5b/eaat7 double mutants, which also exhibit altered response kinetics. Biophysical investigations establish that EAAT7 is an active glutamate transporter with a predominant anion conductance. Our study is the first to demonstrate the direct involvement of post-synaptic glutamate transporters in inhibitory direct synaptic transmission at a central nervous system synapse.

Association between serum chloride levels and estimated glomerular filtration rate among US adults: evidence from NHANES 1999–2018

PurposeChloride, the predominant anion in extracellular fluid from humans, is essential to maintaining homeostasis. One important metric for thoroughly assessing kidney function is the estimated glomerular filtration rate (eGFR). However, the relationship between variations in serum chloride concentration and eGFR in general populations has been poorly studied. Therefore, the purpose of this study is to elucidate the correlation between serum chloride levels and eGFR within the United States’ adult population.MethodsThis cohort study was conducted using data from the National Health and Nutrition Examination Survey (NHANES), which covered the years 1999–2018. We employed multiple linear regression analysis and subgroup analysis to evaluate the correlation between serum chloride concentration and eGFR. To examine the nonlinear association between serum chloride levels and eGFR, restricted cubic spline analyses were employed.ResultsData from 49,008 participants in this cohort study were used for the chloride analysis. In the comprehensively adjusted model, a noteworthy inverse relationship was discovered between chloride plasma concentration and eGFR. Restricted cubic spline analyses revealed a significant nonlinear relationship between chloride levels and eGFR (P for overall < 0.001 and P for nonlinear < 0.001). A significant interaction was observed between eGFR and plasma chloride concentration (all P < 0.001 for interaction) among the subgroups characterized by sex, household income to poverty ratio, BMI, hypertension, and diabetes.ConclusionOur findings suggest that higher levels of chloride plasma concentration were linked to decreased eGFR. These findings underscore the significance of monitoring chloride plasma concentration as a potential indicator for identifying individuals at risk of developing chronic kidney disease (CKD).

Hydrochemical characterization and comprehensive water quality assessment of groundwater within the main stream area of Yishu River.

To gain a comprehensive understanding of the hydrochemical characteristics, controlling factors, and water quality of groundwater in the main stream area of Yishu River (MSYR), a study was conducted using water quality data collected during both the dry and wet seasons. Through statistical analysis, hydrochemical methods, fuzzy comprehensive evaluation, and health risk evaluation modeling, the water chemical characteristics of the main stream area of Yishu River were studied, and the water quality of the area was comprehensively evaluated. The findings indicate that HCO3- and Ca2+ are the predominant anions and cations in the MSYR during the dry and wet seasons, respectively. Moreover, anion concentration in groundwater follows HCO3- > SO42- > NO3- > Cl-, while cations are ranked as Ca2+ > Na+ > Mg2+ > K+. Overall, the groundwater manifests as weakly alkaline and is predominantly classified as hard-fresh water. During the wet season, there is greater groundwater leaching and filtration, with rock and soil materials more readily transferred to groundwater, and the concentrations of main chemical components in groundwater are higher than those during the dry season, and the hydrochemical types are primarily characterized as HCO3-Ca·Mg and SO4·Cl-Ca·Mg types. These results also suggest that the chemical composition of the groundwater in the MSYR is influenced mainly by water-rock interaction. The primary ions originate from the dissolution of silicate rock and carbonate rock minerals, while cation exchange plays a critical role in the hydrogeochemical process. Groundwater in the MSYR is classified mostly as class II water, indicating that it is generally of good quality. However, areas with high levels of class IV and V water are present locally, and NO3- concentration is a crucial factor affecting groundwater quality. In the wet season, more groundwater and stronger mobility lead to greater mobility of NO3- and wider diffusion. Therefore, the risk evaluation model shows that nitrate health risk index is higher in the wet season than it is in the dry season, with children being more vulnerable to health risks than adults. To study groundwater in this area, its hydrochemical characteristics, water quality, and health risk assessment are of great practical significance for ensuring water safety for residents and stable development of social economy.

GEOCHEMICAL AND SANITARY-CHEMICAL CHARACTERISTICS OF WATER SPRINGS OF BOGORODSKY AND LOSIN-PETROVSKY DISTRICTS OF THE MOSCOW REGION

This paper is the results of evaluated of water parameters (COD, pH, electrical conductivity), the content of major ions (Ca2+, Mg2+, Na+, K+, NH4 +, HCO3–, Cl–, SO4 2–, NO3 –) and microelements (Co, Ni, Cu, Zn, Cd, Pb, Sr, Ba, Mn) for 12 springs in the Bogorodsky and Losino-Petrovsky districts of the Moscow region. The waters are slightly acidic-near-neutral (pH 5.5–7.5) with the mineralization from 0.07 to 0.5 g/l, the total hardness is 0.63–5.7 mg- eq/l, the composition of the water is variable. Spring waters are divided into four groups: Cl-SO4-HCO3-(Mg)-Ca; (SO4)-HCO3-Cl-Na-Ca; (Cl)-HCO3-Ca; and mixed composition. Based on the thermodynamic calculation using the Visual-MINTEQ, it was found that the predominant dissolved forms of Ba, Sr, Mn, Zn, Cd, Ni, Co in the waters in the waters of the surveyed springs are free ions. For Cu and Pb, the factors for the formation of migration forms are the predominant anions of water, as well as the presence of organic matter in water. COD values and nitrogen compaund in the waters of individual springs are indicate that the formation of the composition of spring waters is associated with the infiltration of atmospheric precipitation through the modern sediments subject to antropogenic press. The values of other sanitary-chemical indicators (mineralization, pH, total hardness, chlorides, sulfates, mag- nesium, sodium, manganese), the content of standardized microelements are lower than their maximum permissible concentrations in drinking water.

Current Ecological State of the Volga-Akhtuba Floodplain Water Bodies (Using the Example of Dudachenok Shallow Channel)

Current ecological state assessment of the water body located on the Volga-Akhtuba floodplain territory (Dudachenok shallow channel) after its environmental rehabilitation was carried out. It was found that almost all the studied indicators correspond to the approved quality standards with the exception of strontium – 4.5 mg/l (MPC – 0.4 mg/l (Order No. 552 dated December 13, 2016), MPC – 7 .0 mg/l (SanPiN 1.2.3685-21 No. 2 dated January 28, 2021)) and barium – 1.25 mg/l (MPC– 0.74 mg/l (Order No. 552 dated December 13, 2016), MPC – 0.7 mg/l (SanPiN 1.2.3685-21 No. 2 dated January 28, 2021)). It is concluded that it is possible to assign a hydrocarbonate class (predominant anion), calcium group (predominant cation) and second type to a water body. A study of bottom sediments revealed that chloride (36 mg/kg) is one of the predominant anions, calcium (27 mg/kg) and sodium (27 mg/kg) are the predominant cations, which agrees with the obtained water chemical composition data. Chemical and toxicological parameters of bottom sediments were analyzed. It was determined that the quantitative content of metals and pesticides does not exceed the maximum permissible concentrations.

Synthesis of layered double hydroxides from municipal solid waste incineration fly ash for heavy metal adsorption

The process of urbanization has resulted in a continuous growth of the production of municipal solid waste, consequently leading to the increase of municipal solid waste incineration fly ash (MSWI FA) over time. This has prompted the need for effective disposal and value-added utilization strategies for MSWI FA. In this study, a hydrothermal method was employed to synthesize CaAl layered double hydroxides (LDHs) using MSWI FA as the raw material. The main objective was to investigate how different synthesis parameters affect the crystallinity of the layered bimetallic hydroxides. Subsequently, the synthesized LDHs were characterized using various techniques such as BET, SEM, XRD, FT-IR, and XPS. The results revealed the presence of calcium and aluminum cations in the interlayer region of the synthesized material, with chloride ions, sulfate ions, and acetate ions being the predominant anions. Moreover, the formation of LDHs presents an effective approach for the self-purification of leachates derived from MSWI FA. The LDHs exhibited excellent adsorption capacity for Cd2+ and Cu2+ in wastewater, with maximum values of 730 mg·g−1 and 446 mg·g−1, respectively. The adsorption mechanisms involved isomorphous substitution, complexation, as well as the precipitation of hydroxides or interlayer anions. This method presents a novel approach for effectively utilizing MSWI FA to produce environmentally friendly value-added adsorbents.

Assessment of groundwater hydrochemistry, water quality, and health risk in Hainan Island, China

Groundwater is an important source of water for human sustenance. The determination of groundwater quality at island sites is an urgent priority in China, but there are lacking systematic reports relating to them. Here, 63 groups of groundwater samples were collected and analyzed of Hainan Island. The groundwater in the study area is weakly alkaline, mainly comprising hard and soft freshwater. The predominant anions and cations are HCO3−, and Ca2+ and Na+, respectively, and the main water chemistry types are HCO3–Cl–Na and HCO3–Cl–Na–Ca. The chemical evolution of groundwater is mainly affected by water–rock interactions, cation exchange, and human activity. The groundwater is mostly of high quality and, in most areas, is suitable for drinking and irrigation. Contrastingly, the water quality in the west of the island is relatively poor. The spatial distribution of the risk coefficient (HQ) is consistent with the spatial variation in the NO3− concentrations in the groundwater. Notably, there are unacceptable health risks for different groups of people, with infants having the greatest level of impact, followed by children, teenagers, and adults. This study provides a valuable reference for the development and utilization of groundwater resources, as well as the improvement of aquatic ecological conditions on Hainan Island and other island areas worldwide.

Apo state pore opening as functional basis of increased EAAT anion channel activity in episodic ataxia 6.

SLC1A2 and SLC1A3 encode the glial glutamate transporters EAAT2 and EAAT1, which are not only the predominant glutamate uptake carriers in our brain, but also function as anion channels. Two homologous mutations, which predict substitutions of prolines in the center of the fifth transmembrane helix by arginine (P289R EAAT2, P290R EAAT1), have been identified in patients with epileptic encephalopathy (SLC1A2) or with episodic ataxia type 6 (SLC1A3). Both mutations have been shown to impair glutamate uptake and to increase anion conduction. The molecular processes that link the disease-causing mutations to two major alterations of glutamate transporter function remain insufficiently understood. The mutated proline is conserved in every EAAT. Since the pathogenic changes mainly affect the anion channel function, we here study the functional consequences of the homologous P312R mutation in the neuronal glutamate transporter EAAT4, a low capacity glutamate transporter with predominant anion channel function. To assess the impact of charge and structure of the inserted amino acid for the observed functional changes, we generated and functionally evaluated not only P312R, but also substitutions of P312 with all other amino acids. However, only exchange of proline by arginine, lysine, histidine and asparagine were functionally tolerated. We compared WT, P312R and P312N EAAT4 using a combination of cellular electrophysiology, fast substrate application and kinetic modelling. We found that WT and mutant EAAT4 anion currents can be described with a 11-state model of the transport cycle, in which several states are connected to branching anion channel states to account for the EAAT anion channel function. Substitutions of P312 modify various transitions describing substrate binding/unbinding, translocation or anion channel opening. Most importantly, P312R generates a new anion conducting state that is accessible in the outward facing apo state and that is the main determinant of the increased anion conduction of EAAT transporters carrying this mutation. Our work provides a quantitative description how a naturally occurring mutation changes glutamate uptake and anion currents in two genetic diseases.

Groundwater–Surface Water Exchange and Spatial Distribution of Arsenic in Arid and Semi-Arid Regions: The Case of Aksu River in Xinjiang, Northwestern China

The Aksu River, a quintessential inland river, exhibits elevated arsenic (As) concentrations in certain sections of its natural waters. Further investigation is necessary to determine the role of surface water and groundwater (SW-GW) exchanges in contributing to these high As concentrations. Both surface water and groundwater constitute crucial components of the basin water cycle, and the interaction between the two has been a central focus in basin water cycle research. In this study, a total of 59 groundwater samples and 41 surface water samples were collected along the river’s course within the basin. Among the groundwater samples, 18.64% exceeded the permissible drinking limit for As concentrations (10 μg/L), while 39.02% of the surface water samples exceeded this threshold. The water bodies in the Aksu River Basin are mildly alkaline, with total dissolved solids (TDSs) in surface water significantly surpassing those in groundwater. The chemical compositions of surface water and groundwater are strikingly similar, with the predominant anions being chloride (Cl−) and sulfate (SO42−) and the principal cations being sodium (Na+). The dissolution of silicate and carbonate minerals primarily influences the water chemistry characteristics of surface water and groundwater in the Aksu River Basin, followed by the dissolution of salt rocks. Human activities also play a major role in affecting the river’s water quality. The distribution of groundwater with elevated As content is entirely encompassed within the spatial distribution of surface water. Groundwater–surface water exchange plays a vital role in As enrichment in surface water.

Spatial-Temporal Characteristics and Influencing Factors of Lake Water and Groundwater Chemistry in Hulun Lake, Northeast China

Lakes in cold and arid regions are extremely vulnerable to global climate change, and the study of seasonal spatial and temporal fluctuations of lake-groundwater chemistry is of major significance for water resource management and environmental preservation. In this study, we combined hydrogeochemical, multivariate statistical, and spatial interpolation methods to assess spatial and temporal variations of lake and groundwater chemistry in Hulun Lake during the frozen and non-frozen periods. The results show that sodium (Na+) is the most abundant cation in the Hulun Lake area. Bicarbonate (HCO3−) and sulfate (SO42−) are the most predominant anions in the lake, river, and ground water during both seasons. The higher Na+ + K+ concentrations in the frozen season were related to longer circulation time and lower renewable rate. The water chemistry of the lake was of the HCO3-SO4-Cl-Na type and that of groundwater in the east and west regions was of the SO4-Cl-Na and HCO3-Na types, respectively. The chemical compositions of groundwater in the non-frozen season were mainly affected by evaporation and concentration, while rock weathering, evaporation, and human activities jointly controlled groundwater chemical component in the frozen period. Based on hierarchical cluster analysis (HCA) and principal component analysis (PCA) methods, Ca2+, NO3−, and SO42− were identified as the main controlling indicators of the chemical characteristics of groundwater and lake water. The increase of Ca2+ concentration in the center of the lake was related to groundwater discharge along the marginal tectonic fracture zone along the lake shores, which was the potential groundwater discharge area. The unconsolidated aquifer provides recharge channels for groundwater on the eastern side, which has a certain influence on the increase of nutrient concentration (NO3−) in the lake on the eastern shore. This research adds to our rough understanding of the lake-groundwater interaction in Hulun Lake, and provides a scientific foundation for the sustainable use of water resources, as well as the eco-logical integrity preservation in cold and arid regions.

Study and evaluation of the chemical composition of bottom sediments of the Volga-Akhtunisky flood

The chemical composition of the bottom sediments of the Volga-Akhtuba floodplain was assessed. Chlorides (36 mg/kg) were found to be one of the predominant anions, while calcium (27 mg/kg) and sodium (27 mg/kg) were the predominant cations. In terms of pH, the bottom sediments were weakly alkaline throughout the studies. The agrochemical composition of bottom sediments of the studied water body corresponded to lime sapropel due to the content of organic matter in them (4.21%), as well as common forms of nitrogen (0.58%), phosphorus (0.27%) and potassium (1.1%). To assess the chemical and toxicological parameters in samples of bottom sediments, the quantitative content of metals and pesticides was determined. It was found that their content does not exceed the maximum permissible concentrations. An analysis of the IR spectrum data made it possible to establish that the IR spectrum contains absorption bands characteristic of bentonite clays, which have good fertilizing and water-retaining properties.

Enhanced fumion nanocomposite membranes embedded with graphene oxide as a promising anion exchange membrane for fuel cell application

Fumion (FAA3) is a predominant anion exchange membrane/ionomer (AEM/AEI) widely used in energy storage and energy conversion applications. However, its physicochemical stability and electrochemical performance are still quite low for profitable commercialization. Improving the properties of Fumion membrane via the addition of nanofillers or polymer blends is not being widely studied so far. Therefore, in this study, the Fumion membrane with different wt% of graphene oxide (GO) nanofiller was widely investigated for the fuel cell application. The obtained results indicated that water uptake, ionic conductivity, water contact angle, ion exchange capacity, physicochemical stability, and single-cell performance was improved by the incorporation of GO. Notably, the Fumion/GO nanocomposite membrane with 1.08 wt% of GO reached the highest ionic conductivity of 106.83 mS cm−1 at 90 °C, whereas the pristine Fumion exhibited ionic conductivity of only 29.19 mS cm−1. On top of that, the composite membrane achieved a maximum peak power density of 132 mW/cm2 in an alkaline H2/O2 fuel cell with robust open-circuit voltage (OCV) for 150 h. The overall study demonstrates that an appropriate amount of GO addition could result in a promising Fumion anion exchange membrane for electrolyte applications.

Spatial and Temporal Evolution of Groundwater Chemistry of Baotu Karst Water System at Northern China

Karst water quality degradation has been a challenge for domestic and industrial water supplies worldwide. To reveal the possible factors response for karst water quality degradation, Baotu karst spring system is studied as an representative example. In this study, a hydrogeochemical investigation and mathematical, statistical, and geochemical modeling was conducted together to identify the major hydrochemical processes involved in the degradation process. It is found that the karst water is normally fresh, neutral-to-slightly alkaline, with calcium and magnesium as the predominant cations, and bicarbonate and sulfate as the predominant anions. The abnormally high chloride (95.05 mg/L) and nitrate concentrations (148.4 mg/L) give clues to the potential source of contamination in some karst water. The main hydrochemical facies of karst water are HCO3-Ca and HCO3 × SO4-Ca, accounting for 76% of water samples. The water hydrochemistry is controlled mainly by the dissolution of carbonate minerals (calcite, dolomite), followed by the dissolution of silicate and gypsum. The dissolution of calcite and dolomite mostly happens in the recharge area. In the discharge area, the karst water is basically in equilibrium with calcite. The negative SI value of gypsum represents that the water–gypsum interaction is dominated by dissolution along the whole flow path. Cation exchange is observed in the karst water in the indirect recharge area. Along the flow path, the contents of chloride, sulfate, nitrate, and TDS (Total dissolved solids, abbreviated TDS, indicates how many milligrams of dissolved solids are dissolved in one liter of water) vary significantly, which is mostly affected by pollution from human industrial and agricultural activities. The concentrations of major ions were maintained at a low level (&lt;20 mg/L) in the 1960s in karst water. The fast elevation of the parameter values has occurred in the past two decades. The temporal elevation of some pollutants in karst water suggest that global changes (acid rain) and human activity (such as overusing fertilizer) are main factors resulting in the degradation of karst water quality in the study area. The results of this paper provide invaluable information for the management and protection of karst water resources in the urban and rural areas.

The current state of hydrochemical indicators of Lake Kenon– the cooling reservoir of the TPP

A characteristic is given of the current hydrochemical state of the water of Lake Kenon, which is used as a reservoir - a cooler for the Chita TPP. For over 50-years of operation of the station located on its shore, under the conditions of anthropogenic impact, there has been a sharp change in the chemical type of the lakeʼs water. Currently, the predominant anion is the sulfate ion. Above the MPC standard for water of water bodies of fishery significance are the content of magnesium and sulfates and the trace elements: fluorine, vanadium, strontium, molybdenum, copper, tungsten. The concentrations of boron, lithium, bromine are relatively increased, in some samples - iron, manganese, aluminum and barium.

Clues and new evidences in arterial hypertension: unmasking the role of the chloride anion.

The present review will focus on the role of chloride anion in cardiovascular disease, with special emphasis in the development of hypertensive disease and vascular inflammation. It is known that acute and chronic overload of sodium chloride increase blood pressure and have pro-inflammatory and pro-fibrotic effects on different target organs, but it is unknown how chloride may influence these processes. Chloride anion is the predominant anion in the extracellular fluid and its intracellular concentration is dynamically regulated. As the queen of the electrolytes, it is of crucial importance to understand the physiological mechanisms that regulate the cellular handling of this anion including the different transporters and cellular chloride channels, which exert a variety of functions, such as regulation of cellular proliferation, differentiation, migration, apoptosis, intracellular pH and cellular redox state. In this article, we will also review the relationship between dietary, serum and intracellular chloride and how these different sources of chloride in the organism are affected in hypertension and their impact on cardiovascular disease. Additionally, we will discuss the approach of potential strategies that affect chloride handling and its potential effect on cardiovascular system, including pharmacological blockade of chloride channels and non-pharmacological interventions by replacing chloride by another anion.

A Study on Physicochemical Characteristics of Surface Waters in The Area of Dereli (Giresun, Turkey)

Some physicochemical characteristics of surface waters (main river and some streams) in the area of Dereli (Giresun) were investigated. Additionally, certain parameters and quality indices, which may affect the usability of waters for agriculture, were assessed. Available data indicate that the waters have slightly alkaline in character, with pH values ranging from 7.6 to 8.35. The waters are classified as fresh based on their EC values, which ranges from 210–590 µS/cm. The predominant anion in nearly all of the investigated waters is bicarbonate (HCO3-). Sulfate (SO42-) is, after bicarbonate, the second most abundant anion in the waters, followed by chloride (Cl−). Calcium (Ca2+) is the most abundant cation in the waters examined, followed by magnesium (Mg2+), sodium (Na+) and potassium (K+) in descending order. The levels of all ions examined in the waters are in the ranges recommended by the Food and Agriculture Organization (FAO) for irrigation water. Moreover, the calculated values of U.S. Salinity (SAR), Residual sodium carbonate (RSC), Sodium Percentage (Na %), Kelly’s ratio (KR) and Magnesium hazard (MH) indicate suitable of the waters for irrigation. In general, the surface waters in the locations studied are of good physicochemical quality, and also adequate for irrigation.

Proximate analysis of nutrients and in vitro radical scavenging efficacy in selected medicinal plant powders with potential for use as poultry feed additives

The use of antibiotic feed additives in poultry feed is currently discouraged owing to the development of antibiotic-resistant bacteria and other drawbacks. The benefits and importance of phytogenic feed additives as potential alternatives in poultry nutrition include stimulation of digestion, higher feed conversion rate, reduced incidence of disease and profitability. Evaluation of the mineral content and other properties of plant material generates useful information towards rationalizing the use of plants as alternatives to antibiotic feed additives. Concentrations of macro-and micro-minerals in Morinda lucida, Acalypha wilkesiana, Ficus exasperata and standard broiler feed were determined using ICP-MS, and ICP-OES. Levels of degradation of C and N over specific periods of time were evaluated by dry oxidation (Dumas). Radical scavenging activities were investigated using DPPH and ABTS assays while levels of phytochemical constituents were assessed using standard methods. Macro- and micronutrient concentrations in the plant powders were generally higher than those of standard broiler feed. With few exceptions it was observed that the levels of total C and N as well as the C/N ratio in plant powders and standard feed were proportional to storage time. Macronutrients were higher in F. exasperata and A. wilkesiana while micronutrients were higher in A. wilkesiana and M. lucida. The highest total N and C levels were observed in M. lucida while A. wilkesiana showed the highest C/N ratio. Remarkable radical scavenging activities were displayed by A. wilkesiana while the highest total phenolic content (TPC) and total flavonoid content (TFC) were exhibited by aqueous and acetone extracts of F. exasperata respectively. High antioxidant activity was correlated with high total C and C/N ratio of the plant powders. In M. lucida leaf powder, fructose was the dominant sugar at 8,450 mg/kg DW followed by glucose and sucrose with a good amount of Se at 0.32 mg/kg DW. The contents of malic acid were the highest (20,500 mg/kg DW). Organic acids decrease intestinal Escherichia coli and Salmonella species in broilers. Cl− was the most predominant anion. Minerals and organic acids are essential antimicrobial and antioxidant constituents of poultry diets for the maintenance of gut flora health, and their body metabolic, enzymatic and antioxidant defence. This study highlights the nutrients content of the selected plants, providing motivation for further investigation of these species as poultry feed additives.

Components, acidification characteristics, and sources of atmospheric precipitation in Beijing from 1997 to 2020

Policies such as the Air Pollution Prevention and Control Action Plan have been implemented in Beijing to address acid rain pollution. In this study, we evaluate the effects of these policies by analyzing rainfall monitoring data from 1997 to 2020, acidification characteristics, and chemical components of precipitation in Beijing. We found that precipitation pH values had significantly changed in 2008, showing an overall declining trend during 1997–2008 before gradually recovering. The frequency of acid rain was first increased and then decreased, reaching zero levels after 2017. The multi-year average pH in urban (1997–2020), suburban (1997–2020), and background (2004–2020) sites was 5.74 ± 0.67 Â, 6.53 ± 0.54 Â, and 6.49 ± 0.64 Â, respectively. The predominant cations in precipitation were NH4+ and Ca2+, where Ca2+ concentrations dropped from 332.1 μeq·L−1 in 1997 to 179.3 μeq·L−1 by 2015 and 81.39 μeq·L−1 by 2020. In contrast, NH4+ concentrations were first increased from 193.4 μeq·L−1 in 1997 to 270.5 μeq·L−1 in 2015 and then decreased to 206.78 μeq·L−1 by 2020. The concentration of the predominant anions, SO42− and NO3−, was generally decreased; SO42− concentration was decreased from 350.88 μeq·L−1 in 1999 to 88.19 μeq·L−1 in 2020. However, NO3− underwent a down-up-down trend, dropping slowly from 125.3 μeq·L−1 in 1997 to 52.2 μeq·L−1 in 2004, then significantly increasing to 173.06 μeq·L−1 in 2014 before showing a downward trend in volatility. The [SO42−]:[NO3−] ratio was gradually decreased from 3.3 in 1997 to 1.5 in 2015, then dropped to 0.9 in 2020, indicating that the type of precipitation gradually shifted from a predominantly sulfuric acid type to a more mixed type. Conversely, the [Ca2+]:[NH4+] ratio showed a decreasing trend, suggesting NH4+ as the principal neutralizing agent in recent years. The correlation coefficients among the major crustal source components (Ca2+, K+, and Mg2+) were relatively high in the precipitation, suggesting that the contribution from ground dust was significant. The major acidic anions were primarily attributed to human activities.

SLC26A6-selective inhibitor identified in a small-molecule screen blocks fluid absorption in small intestine.

SLC26A6 (also known as putative anion transporter 1 [PAT1]) is a Cl–/HCO3– exchanger expressed at the luminal membrane of enterocytes where it facilitates intestinal Cl– and fluid absorption. Here, high-throughput screening of 50,000 synthetic small molecules in cells expressing PAT1 and a halide-sensing fluorescent protein identified several classes of inhibitors. The most potent compound, the pyrazolo-pyrido-pyrimidinone PAT1inh-B01, fully inhibited PAT1-mediated anion exchange (IC50 ~350 nM), without inhibition of the related intestinal transporter SLC26A3 (also known as DRA). In closed midjejunal loops in mice, PAT1inh-B01 inhibited fluid absorption by 50%, which increased to >90% when coadministered with DRA inhibitor DRAinh-A270. In ileal loops, PAT1inh-B01 blocked fluid absorption by >80%, whereas DRAinh-A270 was without effect. In colonic loops, PAT1inh-B01 was without effect, whereas DRAinh-A270 completely blocked fluid absorption. In a loperamide constipation model, coadministration of PAT1inh-B01 with DRAinh-A270 increased stool output compared with DRAinh-A270 alone. These results provide functional evidence for complementary and region-specific roles of PAT1 and DRA in intestinal fluid absorption, with PAT1 as the predominant anion exchanger in mouse ileum. We believe that PAT1inh-B01 is a novel tool to study intestinal ion and fluid transport and perhaps a drug candidate for small intestinal hyposecretory disorders such as cystic fibrosis–related meconium ileus and distal intestinal obstruction syndrome.