Graphical, statistical and index-based techniques integrated for identifying the hydrochemical fingerprints and groundwater quality of In Salah, Algerian Sahara.

Groundwater, a predominant reservoir of freshwater, plays a critical role in providing a sustainable potable water and water for agricultural and industry uses in the In Salah desert region of Algeria. This research collected 82 underground water samples from Albian aquifers to assess water quality and identify hydrogeochemical processes influencing mineralization. To achieve this objective, various methods were employed to evaluate water quality based on its intended uses. The drinking water quality index utilized revealed the water potability status, while the indicators of irrigation potability were employed to evaluate its quality for agricultural purposes. Additionally, an assessment of groundwater susceptibility to corrosion and scaling in an industrial context was conducted using several indices, e.g., Langelier index, Larson-Skold index, Ryznar index, chloride-sulfate mass ratio, Puckorius index, aggressiveness index, and the Revelle index. The findings of this study revealed that the groundwater quality for consumption fell into four categories: good (2.44%), fair (29.27%), poor (65.85%), and non-potable (2.44%). Concerning agricultural irrigation, the indexical results indicated that 15.85% of the waters exhibited adequate quality, while 84.15% were questionable for irrigation. Calculations based on various corrosion and scaling evaluation indices showed that most wells were prone to corrosion, with a tendency for calcium bicarbonate deposit formation. Furthermore, the hydrochemical study identified three water types: Na-Cl (53.66%), Ca-Mg-Cl (37.80%), and Ca-Cl (8.54%) waters. Analyses of correlation matrices, R-type clustering, factor loadings, Gibbs diagrams, scatterplots, and chloro-alkaline indices highlighted that the chemistry of the Albian groundwater is fundamentally impacted by a number of processes such as silicate weathering, evaporite dissolution, ionic exchange, and anthropogenic inputs, that played impactful role in the aquifer's water chemistry.

A time-averaged serum bicarbonate-based nomogram to predict the probability of residual kidney function preservation for patients undergoing peritoneal dialysis.

OBJECTIVE: Residual kidney function (RKF) is an important prognostic indicator in peritoneal dialysis (PD) patients. So far, there are no prediction tools available for RKF, and the association between serum bicarbonate and RKF has received little attention in patients with PD. We aimed to develop a nomogram for the preservation of RKF based on the time-averaged serum bicarbonate (TA-Bic) levels. PATIENTS AND METHODS: A prediction model was established by conducting a retrospective cohort study of 151 PD patients who had been treated at the First Affiliated Hospital of Anhui Medical University. The nomogram was developed using a multivariate Cox regression model. The discrimination, calibration, and clinical utility of the model were evaluated by the C-index, receiver operating curve (ROC) curve, calibration curve, and decision curve analysis. RESULTS: In the elderly PD onset, higher baseline values of residual glomerular filtration rate, total Kt/V and higher TA-Bic levels were identified as protective predictors of RKF loss. The nomogram was conducted on the basis of the minimum value of the Akaike Information Criterion and Bayesian Information Criterion with a reasonable C-index of 0.766, showing great discrimination, proper calibration, and high potential for clinical practice. Through the total score of the nomogram, the patients were classified into the high-risk group and low-risk group, and a higher cumulative incidence of complete RRF loss was found in the high-risk group compared with the patients in the low-risk group. CONCLUSIONS: The novel predictive nomogram model can predict the probability of RKF preservation in long-term PD patients with high accuracy. Future studies are needed to externally validate the current nomogram before clinical application.

Symmetric dimethylarginine correlates with the urea, creatinine, potassium, and clinical scores in feline urethral obstructions.

BACKGROUND: A urethral obstruction (UO) is an emergency commonly observed in male cats, which can result in significant clinical and laboratory alterations, leading to complications and death. OBJECTIVES: This study aimed to correlate symmetric dimethylarginine (SDMA) with the urea, creatinine, potassium, and bicarbonate levels in cats with UO. In addition, the correlation between clinical score and time of obstruction was evaluated. METHODS: Thirty male cats were selected and allocated into a control group (CG, n = 13) and an obstruction group (OG, n = 17). The laboratory analyses were conducted before treatment (M0) and at different times after treatment (12 h [M12], 24 h [M24], and 48 h [M48]). Correlations were established between SDMA and creatinine, urea, bicarbonate, potassium, time of obstruction, and the clinical score. RESULTS: A strong correlation (r > 0.6) was observed between SDMA and creatinine, urea, and potassium in the OG. Furthermore, there was substantial agreement (kappa value) between SDMA and creatinine at M24. A higher clinical score was associated with a longer time of obstruction. In the OG, at M48, the SDMA and creatinine levels were 50% and 41.2% higher, respectively. CONCLUSIONS: A correlation was observed between SDMA and creatinine in obstructed cats, and significant agreement between these values was observed 24 h after the unblocking treatment. A correlation among SDMA, urea, and potassium was observed. Approximately 9% more cats continued to have elevated SDMA levels after 48 h of treatment compared to creatinine. This suggests a slightly lower sensitivity of the latter biomarker but does not exclude the possibility of congruent and normalized values after a longer evaluation period.

Pentavalent U Reactivity Impacts U Isotopic Fractionation during Reduction by Magnetite.

Meaningful interpretation of U isotope measurements relies on unraveling the impact of reduction mechanisms on the isotopic fractionation. Here, the isotope fractionation of hexavalent U [U(VI)] was investigated during its reductive mineralization by magnetite to intermediate pentavalent U [U(V)] and ultimately tetravalent U [U(IV)]. As the reaction proceeded, the remaining aqueous phase U [containing U(VI) and U(V)] systematically carried light isotopes, whereas in the bicarbonate-extracted solution [containing U(VI) and U(V)], the δ238U values varied, especially when C/C0 approached 0. This variation was interpreted as reflecting the variable relative contribution of unreduced U(VI) (δ238U < 0‰) and bicarbonate-extractable U(V) (δ238U > 0‰). The solid remaining after bicarbonate extraction included unextractable U(V) and U(IV), for which the δ238U values consistently followed the same trend that started at 0.3-0.5‰ and decreased to ∼0‰. The impact of PIPES buffer on isotopic fractionation was attributed to the variable abundance of U(V) in the aqueous phase. A few extremely heavy bicarbonate-extracted δ238U values were due to mass-dependent fractionation resulting from several hypothesized mechanisms. The results suggest the preferential accumulation of the heavy isotope in the reduced species and the significant influence of U(V) on the overall isotopic fractionation, providing insight into the U isotope fractionation behavior during its abiotic reduction process.

The role of soluble adenylyl cyclase in sensing and regulating intracellular pH.

Soluble adenylyl cyclase (sAC) differs from transmembrane adenylyl cyclases (tmAC) in many aspects. In particular, the activity of sAC is not regulated by G-proteins but by the prevailing bicarbonate concentrations inside cells. Therefore, sAC serves as an exquisite intracellular pH sensor, with the capacity to translate pH changes into the regulation of localization and/or activity of cellular proteins involved in pH homeostasis. In this review, we provide an overview of literature describing the regulation of sAC activity by bicarbonate, pinpointing the importance of compartmentalization of intracellular cAMP signaling cascades. In addition, examples of processes involving proton and bicarbonate transport in different cell types, in which sAC plays an important regulatory role, were described in detail.

Comparison of bicarbonate Ringer's solution with lactated Ringer's solution among postoperative outcomes in patients with laparoscopic right hemihepatectomy: a single-centre randomised controlled trial.

The study was aimed to investigate the positive impact of bicarbonate Ringer's solution on postoperative outcomes in patients who underwent laparoscopic right hemihepatectomy. Patients in the two groups were infused with lactated Ringer's solution (LRS, n = 38) and the bicarbonate Ringer's solution (BRS, n = 38) at a rate of 5 ml·kg-1·h-1. The stroke volume was monitored and 200 ml of hydroxyethyl starch with 130/0.4 sodium chloride injection (Hes) of a bolus was given in the first 5-10 min. The main outcome was to test lactic acid (LAC) concentration before and after surgery. The concentrations of LAC in the LRS group were higher than in the BRS group at 2 h after operation began, at the end of the operation and 2 h after the operation. Overall, the parameters including pH, base excess (BE), HCO3-, aspartate transaminase (AST) and alanine transaminase (ALT) were improved. The values of bilirubin in the LRS group were higher and albumin were lower than in the BRS group at post-operation 1st and 2nd day (P<0.05). The time of prothrombin time (PT) and activated partial thromboplastin time (APTT) in the LRS group were longer than that in the BRS group at post-operation 1st and 2nd day (P<0.05). Likewise, the concentrations of Mg2+, Na+ and K+ also varied significantly. The length of hospital was reduced, and the incidence of premature ventricular contractions (P = 0.042) and total complications (P = 0.016) were lower in group BRS. TRIAL REGISTRATION: The study was registered at clinicalTrials.gov with the number ChiCTR2000038077 on 09/09/2020.

Polyphenol analysis in human milk by a rapid, cost-effective, and accurate micromethod: translational development.

OBJECTIVE: To develop a rapid method for analysing polyphenols, which are potentially active antioxidants against neonatal oxidative stress, from small human milk (HM) volumes. METHODS: Acid and alkaline extractions were compared using two dyes: Folin-Ciocalteu and Fast Blue BB. Linearity, sensitivity, recovery percentage, polyphenol content, precision, and stability were assessed in 14 HM samples and compared using the Kruskal-Wallis H test (p<0.05). The best technique was applied to 284 HM samples to determine their polyphenolic content and its association with maternal diet by multifactorial linear regression. RESULTS: Acidic extraction successfully recovered the gallic acid reference standard, whereas alkaline extraction overestimated it. Calibration curves for all methods were linear (R2>0.96) up to 500 mg/L. All bicarbonate-based Folin-Ciocalteu methods assayed were stable and repeatable, whereas Fast Blue BB-based variants were not. HM polyphenols (mean=94.68 mg/L) positively correlated to the dietary intake of hydroxycinnamic acids, the most consumed polyphenolic family in this population. CONCLUSIONS: A bicarbonate-based Folin-Ciocalteu micromethod allowed the accurate determination of polyphenols in HM, which might be useful for translational research settings and HM banks.

The role of Na+-coupled bicarbonate transporters (NCBT) in health and disease.

Cellular and organism survival depends upon the regulation of pH, which is regulated by highly specialized cell membrane transporters, the solute carriers (SLC) (For a comprehensive list of the solute carrier family members, see: https://www.bioparadigms.org/slc/ ). The SLC4 family of bicarbonate (HCO3-) transporters consists of ten members, sorted by their coupling to either sodium (NBCe1, NBCe2, NBCn1, NBCn2, NDCBE), chloride (AE1, AE2, AE3), or borate (BTR1). The ionic coupling of SLC4A9 (AE4) remains controversial. These SLC4 bicarbonate transporters may be controlled by cellular ionic gradients, cellular membrane voltage, and signaling molecules to maintain critical cellular and systemic pH (acid-base) balance. There are profound consequences when blood pH deviates even a small amount outside the normal range (7.35-7.45). Chiefly, Na+-coupled bicarbonate transporters (NCBT) control intracellular pH in nearly every living cell, maintaining the biological pH required for life. Additionally, NCBTs have important roles to regulate cell volume and maintain salt balance as well as absorption and secretion of acid-base equivalents. Due to their varied tissue expression, NCBTs have roles in pathophysiology, which become apparent in physiologic responses when their expression is reduced or genetically deleted. Variations in physiological pH are seen in a wide variety of conditions, from canonically acid-base related conditions to pathologies not necessarily associated with acid-base dysfunction such as cancer, glaucoma, or various neurological diseases. The membranous location of the SLC4 transporters as well as recent advances in discovering their structural biology makes them accessible and attractive as a druggable target in a disease context. The role of sodium-coupled bicarbonate transporters in such a large array of conditions illustrates the potential of treating a wide range of disease states by modifying function of these transporters, whether that be through inhibition or enhancement.

Isolation of ammonium bicarbonate by reactive distillation of food waste digestate liquor.

Distillation is among the best techniques for management of ammoniacal nitrogen in anaerobic digestate; however, the suitability of the conventional system is neglected in favor of using more advanced setups. This investigation proves the reliability of the classical batch distillation apparatus for high throughput separation of solid crystals of ammonium bicarbonate from food waste digestate (FWD) liquor. Three replicates were carried out: 80 g of FWD liquor with a content of 50 g/L NH4HCO3 was processed for 7.5 h under minimum heating power (<60 °C) and 200 rpm to avoid excessive foam formation. After performing the reactive distillation, 81 % of NH4HCO3 was recovered as white solid crystals at the top of the distillation still. Although the distillation provided a solid material with the same structure and composition as those of the reagent-grade NH4HCO3, the stability of the isolated inorganic fertilizer was poorer, and it could lead to pollution swapping.

Overcoming aggregation with laser heated nanoelectrospray mass spectrometry: thermal stability and pathways for loss of bicarbonate from carbonic anhydrase II.

Variable temperature electrospray mass spectrometry is useful for multiplexed measurements of the thermal stabilities of biomolecules, but the ionization process can be disrupted by aggregation-prone proteins/complexes that have irreversible unfolding transitions. Resistively heating solutions containing a mixture of bovine carbonic anhydrase II (BCAII), a CO2 fixing enzyme involved in many biochemical pathways, and cytochrome c leads to complete loss of carbonic anhydrase signal and a significant reduction in cytochrome c signal above ∼72 °C due to aggregation. In contrast, when the tips of borosilicate glass nanoelectrospray emitters are heated with a laser, complete thermal denaturation curves for both proteins are obtained in <1 minute. The simultaneous measurements of the melting temperature of BCAII and BCAII bound to bicarbonate reveal that the bicarbonate stabilizes the folded form of this protein by ∼6.4 °C. Moreover, the temperature dependences of different bicarbonate loss pathways are obtained. Although protein analytes are directly heated by the laser for only 140 ms, heat conduction further up the emitter leads to a total analyte heating time of ∼41 s. Pulsed laser heating experiments could reduce this time to ∼0.5 s for protein aggregation that occurs on a faster time scale. Laser heating provides a powerful method for studying the detailed mechanisms of cofactor/ligand loss with increasing temperature and promises a new tool for studying the effect of ligands, drugs, growth conditions, buffer additives, or other treatments on the stabilities of aggregation-prone biomolecules.

Calcareous termite mounds in South Africa are ancient carbon reservoirs.

Ecosystems that offer carbon sequestration by leaching bicarbonate to groundwater are valuable natural capital. One region that may offer this service is the west coast of South Africa. Over 20 % is covered by soil mounds ("heuweltjies") up to 40 m diameter, 2 m high, inhabited by the southern harvester termite Microhodotermes viator and enriched in soil organic and inorganic carbon and soluble minerals. We aimed to generate radiogenic and stable isotope data for soils and groundwater in a region where these data are absent, to 1) verify the atmosphere-soil-groundwater link, and 2) resolve the timing and pattern of calcite dissolution and water infiltration in the landscape. Results show that soil and groundwater sulfate have the same marine aerosol source. Episodic calcite dissolution in mound centers, which increased during periods of global cooling, has been set against background input of marine aerosols since before the Last Glacial according to radiocarbon (14C) ages. Our data push back soil organic carbon 14C ages of inhabited termite mounds to 13-19 ka (kiloannum, thousand years before present), nest carbonate 14C ages to 33 ka, and mound soil carbonate 14C ages to 34 ka, making these the oldest active termite features ever dated. These ages are consistent with soil organic carbon and carbonate 14C ages of regional, non-mound, coastal petrocalcic horizons formed by accumulation of carbonate leached from their overlying aeolian dune fields. Harvesting activities of termites inject younger organic material around nests >1 m deep, leading to continuous renewal of important soil carbon reservoirs at depth. Termite bioturbation increases the system's ability to dissolve carbonate. The central, bioturbated part of the mounds have greater infiltration depths and greater calcite dissolution, whereas surrounding soils experienced more surface runoff. Calcareous termite mounds offer a mechanism to sequester CO2 through dissolution and leaching of soil carbonate-bicarbonate to groundwater.

CFTR function is impaired in a subset of patients with pancreatitis carrying rare CFTR variants.

BACKGROUND: Many affected by pancreatitis harbor rare variants of the cystic fibrosis (CF) gene, CFTR, which encodes an epithelial chloride/bicarbonate channel. We investigated CFTR function and the effect of CFTR modulator drugs in pancreatitis patients carrying CFTR variants. METHODS: Next-generation sequencing was performed to identify CFTR variants. Sweat tests and nasal potential difference (NPD) assays were performed to assess CFTR function in vivo. Intestinal current measurement (ICM) was performed on rectal biopsies. Patient-derived intestinal epithelial monolayers were used to evaluate chloride and bicarbonate transport and the effects of a CFTR modulator combination: elexacaftor, tezacaftor and ivacaftor (ETI). RESULTS: Of 32 pancreatitis patients carrying CFTR variants, three had CF-causing mutations on both alleles and yielded CF-typical sweat test, NPD and ICM results. Fourteen subjects showed a more modest elevation in sweat chloride levels, including three that were provisionally diagnosed with CF. ICM indicated impaired CFTR function in nine out of 17 non-CF subjects tested. This group of nine included five carrying a wild type CFTR allele. In epithelial monolayers, a reduction in CFTR-dependent chloride transport was found in six out of 14 subjects tested, whereas bicarbonate secretion was reduced in only one individual. In epithelial monolayers of four of these six subjects, ETI improved CFTR function. CONCLUSIONS: CFTR function is impaired in a subset of pancreatitis patients carrying CFTR variants. Mutations outside the CFTR locus may contribute to the anion transport defect. Bioassays on patient-derived intestinal tissue and organoids can be used to detect such defects and to assess the effect of CFTR modulators.

Quenching residual H2O2 from UV/H2O2 with granular activated carbon: A significant impact of bicarbonate.

UV/H2O2 has been used as an advanced oxidation process to remove organic micropollutants from drinking water. It is essential to quench residual H2O2 to prevent increased chlorine demand during chlorination/chloramination and within distribution systems. Granular activated carbon (GAC) filter can quench the residual oxidant and eliminate some of the dissolved organic matter. However, knowledge on the kinetics and governing factors of GAC quenching of residual H2O2 from UV/H2O2 and the mechanism underlying the enhancement of the process by HCO3- is limited. Therefore, this study aimed to analyse the kinetics and influential factors, particularly the significant impact of bicarbonate (HCO3-). H2O2 decomposition by GAC followed first-order kinetics, and the rate constants normalised by the GAC dosage (kn) were steady (1.6 × 10-3 L g-1 min-1) with variations in the GAC dosage and initial H2O2 concentration. Alkaline conditions favour H2O2 quenching. The content of basic groups exhibited a stronger correlation with the efficiency of GAC in quenching H2O2 than did the acidic groups， with their specific kn values being 8.9 and 2.4 min-1 M-1, respectively. The presence of chloride, sulfate, nitrate, and dissolved organic matter inhibited H2O2 quenching, while HCO3- promoted it. The interfacial hydroxyl radical (HO•) zones were visualised on the GAC surface, and HCO3- addition increased the HO• concentration. HCO3- increased the concentration of persistent free radicals (PFRs) on the GAC surface, which mainly contributed to HO• generation. A significant enhancement of HCO3- on H2O2 quenching by GAC was also verified in real water. This study revealed the synergistic mechanism of HCO3- and GAC on H2O2 quenching and presents the potential applications of residual H2O2 in the H2O2-based oxidation processes.

Refinement of kinetic model and understanding the role of dichloride radical (Cl2•-) in radical transformation in the UV/NH2Cl process.

The ultraviolet/monochloramine (UV/NH2Cl) process is an emerging advanced oxidation process with promising prospects in water treatment. Previous studies developed kinetic models of UV/NH2Cl for simulating radical concentrations and pollutant degradation. However, the reaction rate constants of Cl2•- with bicarbonate and carbonate (kCl2•-, HCO3- and kCl2•-, CO32-) were overestimated in literature. Consequently, when dosing 1 mM chloride and 1 mM bicarbonate, the current models of UV/NH2Cl severely under-predicted the experimental concentrations of three important radicals (i.e., hydroxyl radical (HO•), chlorine radical (Cl•), and dichloride radical (Cl2•-)) with great deviations (> 90 %). To investigate this issue, the transformation reactions among these three radicals in UV/NH2Cl were systematically studied. For the first time, it was found that in addition to Cl•, Cl2•- was also an important parent radical of HO• in the presence of chloride, and chloride could effectively compensate the inhibitory effect of bicarbonate on HO• generation in the system. Moreover, reactions and rate constants in current models were scrutinized from corresponding literature, and the reaction rate constants of Cl2•- with bicarbonate and carbonate (kCl2•-, HCO3- and kCl2•-, CO32-) were reevaluated to be 1.47 × 105 and 3.78 × 106 M-1s-1, respectively, by laser flash photolysis. With the newly obtained rate constants, the refined model could accurately simulate concentrations of all three radicals under different chloride and bicarbonate dosages with satisfactory deviations (< 30 %). Meanwhile, the refined model performed much better in predicting pollutant degradation and radical contribution compared with the unrefined model (with the previously estimated kCl2•-, HCO3- and kCl2•-, CO32-). The results of this study enhanced the accuracy and applicability of the kinetic model of UV/NH2Cl, and deepened the understanding of radical transformation in the process.

Effects of Enteric-Coated Formulation of Sodium Bicarbonate on Bicarbonate Absorption and Gastrointestinal Discomfort.

Sodium bicarbonate is used as an ergogenic supplement to enhance people's performances in various exercises. This study aimed to evaluate the effects of intestinal delivery of sodium bicarbonate on bicarbonate absorption and associated side effects in an experimental human trial. After preparing and assessing enteric-coated and uncoated sodium bicarbonate tablet formulations, pharmacokinetic analysis and gastrointestinal symptom tests were performed after oral administration in the human body. The dose required to increase blood bicarbonate concentration over 5 mmol∙L-1 for the purpose of improving performance during high-intensity exercise was also determined. Enteric-coated tablet formulation protects sodium bicarbonate under acidic conditions and releases bicarbonate in the intestine. Enteric-coated tablet formulation also reduced the oral dose required to achieve a blood bicarbonate concentration over 5 mmol∙L-1 from 300 mg∙kg-1 of uncoated tablet formulation to 225 mg∙kg-1. Gastrointestinal discomfort was significantly decreased for the group given 225 mg∙kg-1 enteric-coated tablets compared to that given 300 mg∙kg-1 uncoated tablets. These results suggest that enteric-coated tablet formulation could reduce the oral dose required in order to achieve a blood bicarbonate concentration over 5 mmol∙L-1 by 25%, from 300 mg∙kg-1 to 225 mg∙kg-1, along with its ability to reduce gastrointestinal discomfort associated with the dosage.

Photosynthetic response of Chara braunii towards different bicarbonate concentrations.

A variety of inorganic carbon acquisition modes have been proposed in Characean algae, however, a broadly applicable inorganic carbon uptake mechanism is unknown for the genus Chara. In the present study, we analyzed if C. braunii can efficiently use HCO3 - as a carbon source for photosynthesis. For this purpose, C. braunii was exposed to different concentrations of NaHCO3 - at different time scales. The photosynthetic electron transport through photosystem I (PSI) and II (PSII), the maximum electron transport rate (ETRmax ), the efficiency of the electron transport rate (α, the initial slope of the ETR), and the light saturation point of photosynthesis (Ek ) were evaluated. Additionally, pigment contents (chlorophyll a, chlorophyll b, and carotenoids) were determined. Bicarbonate addition positively affected ETRmax , after direct HCO3 - application, of both PSII and PSI, but this effect seems to decrease after 1 h and 24 h. Similar trends were seen for Ek , but no significant effect was observed for α. Pigment contents showed no significant changes in relation to different HCO3 - concentrations. To evaluate if cyclic electron flow around PSI was involved in active HCO3 - uptake, the ratio of PSI ETRmax /PSII ETRmax was calculated but did not show a distinctive trend. These results suggest that C. braunii can utilize NaHCO3 - in short-term periods as a carbon source but could rely on other carbon acquisition mechanisms over prolonged time periods. These observations suggest that the minor role of HCO3 - as a carbon source for photosynthesis in this alga might differentiate C. braunii from other examined Chara spp.

Efficient Cr(VI) removal by pyrite/porous biochar: Critical role of potassium salt and sulphur.

The excessive accumulation of hexavalent chromium (Cr(VI)) in the environment poses a risk to environment and human health. In the present study, a potassium bicarbonate-modified pyrite/porous biochar composite (PKBC) was prepared in a one-step process and applied for the efficient removal of Cr(VI) in wastewater. The results showed that PKBC can significantly remove Cr(VI) within 4 h over a wide range of pH (2-11). Meanwhile, the PKBC demonstrated remarkable resistance towards interference from complex ions. The addition of potassium bicarbonate increased the pore structure of the material and promoted the release of Fe2+. The reduction of Cr(VI) in aqueous solution was primarily attributed to the Fe(II)/Fe(III) redox cycle. The sulphur species achieved Fe(II)/Fe(III) cycle through electron transfer with iron, thus ensuring the continuous reduction capacity of PKBC. Besides, the removal rate was also maintained at more than 85% in the actual water samples treatment process. This work provides a new way to remove hexavalent chromium from wastewater and demonstrates the potential critical role of potassium bicarbonate and sulphur.

Binding Sites of Bicarbonate in Phosphoenolpyruvate Carboxylase.

Phosphoenolpyruvate carboxylase (PEPC) is used in plant metabolism for fruit maturation or seed development as well as in the C4 and crassulacean acid metabolism (CAM) mechanisms in photosynthesis, where it is used for the capture of hydrated CO2 (bicarbonate). To find the yet unknown binding site of bicarbonate in this enzyme, we have first identified putative binding sites with nonequilibrium molecular dynamics simulations and then ranked these sites with alchemical free energy calculations with corrections of computational artifacts. Fourteen pockets where bicarbonate could bind were identified, with three having realistic binding free energies with differences with the experimental value below 1 kcal/mol. One of these pockets is found far from the active site at 14 Å and predicted to be an allosteric binding site. In the two other binding sites, bicarbonate is in direct interaction with the magnesium ion; neither sequence alignment nor the study of mutant K606N allowed to discriminate between these two pockets, and both are good candidates as the binding site of bicarbonate in phosphoenolpyruvate carboxylase.

Arterial blood gas analysis predicts futile recanalization in mechanical thrombectomy-treated acute ischemic stroke patients: a multicenter study.

OBJECTIVE: It is known that providing recanalization alone in large vessel occlusions is not sufficient to provide a good 90-day clinical outcome. It is advocated that neuroprotection should be increased before endovascular treatment and that the penumbra should be protected from reperfusion damage after recanalization. However, the effects of blood gas parameters before and after mechanical thrombectomy on clinical outcomes are not clear. The objective of this study is to assess the effectiveness of serial blood gas measures in accurately predicting futile recanalization at an early stage. PATIENTS AND METHODS: This study is a multicenter inquiry that collected data in a prospective manner and analyzed it retrospectively. Patients with a 2b-3 thrombolysis in cerebral infarction (TICI) score after mechanical thrombectomy for recanalization were consecutively analyzed from July 2022 to March 2023. Arterial blood gas parameters, including pH, oxygen saturation (SaO2), partial carbon dioxide pressure (PaCO2), partial oxygen pressure (PaO2), lactate, and bicarbonate (HCO3), were measured at four time points: before mechanical thrombectomy treatment (preoperative), immediately after recanalization (postoperative 1st), during the 3rd hour (postoperative 3rd), and at the 5th hour (postoperative 5th). The patients were categorized into groups based on their modified Rankin Scale (mRS) scores. RESULTS: The study included 136 patients with an average age of 69.71±11.22. The postoperative 1st-hour SaO2 values were lower in the mRS 3-6 group (p=0.038). The postoperative pH and lactate mean were greater in the mRS 3-6 group than in the 0-2 group (p=0.038 and 0.018, respectively). In logistic regression, a unit rise in lactate increased poor functional outcomes 1,632 times (p=0.024). Early neurological recovery was associated with decreased postoperative 3rd-hour lactate (p=0.014). The mean postoperative PaO2 (average of 1, 2, 3 PaO2) was higher in those with symptomatic cerebral bleeding (p=0.044). CONCLUSIONS: Monitoring lactate and pH levels in AIS patients who have had mechanical recanalization can be utilized to predict mortality and morbidity, especially in the first five hours after the procedure. Graphical Abstract: https://www.europeanreview.org/wp/wp-content/uploads/Graphical-abstract-8.jpg.

Dissolution Profiles of Oral Disintegrating Tablet with Taste Masking Granule Polymer Coating in Biorelevant Bicarbonate Buffer.

The current study aimed to explore the impact of buffer species on the dissolution behavior of orally disintegrating tablets (ODT) containing a basic polymer and its influence on bioequivalence (BE) prediction. Fexofenadine hydrochloride ODT formulations were used as the model formulations, Allegra® as the reference formulation, and generic formulations A and B as the test formulations. Allegra®, generic A, and generic B are ODT formulations that contain aminoalkyl methacrylate copolymers E (Eudragit® E, EUD-E), a basic polymer commonly used to mask the bitter taste of drugs. Both generic A and generic B have been known to be bioequivalent to Allegra®. The dissolution tests were conducted using a compendial paddle, with either bicarbonate (10 mM, pH 6.8) or phosphate buffer (25 mM, pH 6.8) as the dissolution media. A floating lid was employed to cover the surface of the bicarbonate buffer to prevent volatilization. Results indicated that in phosphate buffer, the dissolution profiles of Allegra and generic B significantly varied from that of generic A, whereas in the bicarbonate buffer, the dissolution profiles of Allegra, generic A, and generic B were comparable. These findings suggest that the use of bicarbonate buffer may offer a more precise prediction of human bioequivalence compared to phosphate buffer.