Thermodynamic simulation of stepwise precipitation of NH_4VO_(3)and NaHCO_(3)from carbonating Na_(3)VO_(4)solution

Thermodynamic simulation was conducted to design a new process of stepwise precipitating NH_4VO_(3)and NaHCO_(3)from regulating the CO_(2)carbonation of Na_(3)VO_(4)solution.Firstly,a new V(V)speciation model for the aqueous solution containing vanadate and carbonate is established by using the Bromley-Zemaitis activity coefficient model.Subsequently,thermodynamic equilibrium calculations are conducted to clarify the behavior of vanadium,carbon,sodium,and impurity species in atmospheric or high-pressure carbonation.To ensure the purity and recovery of vanadium products,Na_(3)VO_(4)solution is initially carbonated to the pH of 9.3-9.4,followed by precipitating NH_4VO_(3)by adding(NH_4)_(2)CO_(3).After vanadium precipitation,the solution is deeply carbonated to the final pH of 7.3-7.5 to precipitate NaHCO_(3),and the remaining solution is recycled to dissolve Na_(3)VO_(4)crystals.Finally,verification experiments demonstrate that 99.1%of vanadium and 91.4%of sodium in the solution are recovered in the form of NH_4VO_(3)and NaHCO_(3),respectively.

The photosynthetic oxygen evolution does not exclude the important role and contribution of bicarbonate photolysis

Photosynthesis is the most important biochemical reaction on Earth. It has co-evolved and developed with the Earth, driving the biogeochemical cycle of all elements on the planet and serving as the only chemical process in nature that can convert light energy into chemical energy. Some heavy oxygen isotopic(^(18)O) labeling experiments have"conclusively" demonstrated that the oxygen released by photosynthesis comes only from water and are written into textbooks. However, it is not difficult to find that bicarbonate has never been excluded from the direct substrate of photosynthesis from beginning to end during the history of photosynthesis research. No convincing mechanism can be used to explain photosynthetic oxygen evolution solely from water photolysis. The bicarbonate effect, the Dole effect, the thermodynamic convenience of bicarbonate photolysis, the crystal structure characteristics of photosystem Ⅱ, and the reinterpretation of heavy oxygen isotopic labeling(^(18)O)experiments all indicate that the photosynthetic oxygen evolution does not exclude the important role and contribution of bicarbonate photolysis. The recently proposed view that bicarbonate photolysis is the premise of water photolysis, bicarbonate photolysis and water photolysis work together with a 1:1(mol/mol) stoichiometric relationship, and the stoichiometric relationship between oxygen and carbon dioxide released during photosynthetic oxygen evolution is also 1:1, has excellent applicability and objectivity, which can logically and reasonably explain the precise coordination between light and dark reactions during photosynthesis, the bicarbonate effect, the Dole effect, the Kok cycle and the neutrality of water and carbon in nature.This is of great significance for constructing the bionic artificial photosynthetic reactors and scientifically answering the question of the source of elemental stoichiometric relationships in nature.

A cascade of in situ conversion of bicarbonate to CO_(2) and CO_(2) electroreduction in a flow cell with a Ni-N-S catalyst

Combination of CO_(2) capture using inorganic alkali with subsequently electrochemical conversion of the resultant HCO_(3)^(-)to high-value chemicals is a promising route of low cost and high efficiency.The electrochemical reduction of HCO_(3)^(-)is challenging due to the inaccessible of negatively charged molecular groups to the electrode surface.Herein,we adopt a comprehensive strategy to tackle this challenge,i.e.,cascade of in situ chemical conversion of HCO_(3)^(-)to CO_(2) and CO_(2) electrochemical reduction in a flow cell.With a tailored Ni-N-S single atom catalyst(SACs),where sulfur(S)atoms located in the second shell of Ni center,the CO_(2)electroreduction(CO_(2)ER)to CO is boosted.The experimental results and density functional theory(DFT)calculations reveal that the introduction of S increases the p electron density of N atoms near Ni atom,thereby stabilizing^(*)H over N and boosting the first proton coupled electron transfer process of CO_(2)ER,i.e.,^(*)+e^(-)+^(*)H+^(*)CO_(2)→^(*)COOH.As a result,the obtained catalyst exhibits a high faradaic efficiency(FE_(CO)~98%)and a low overpotential of 425 mV for CO production as well as a superior turnover frequency(TOF)of 47397 h^(-1),outcompeting most of the reported Ni SACs.More importantly,an extremely high FECOof 90%is achieved at 50 mA cm^(-2)in the designed membrane electrode assembly(MEA)cascade electrolyzer fed with liquid bicarbonate.This work not only highlights the significant role of the second coordination on the first coordination shell of the central metal for CO_(2)ER,but also provides an alternative and feasible strategy to realize the electrochemical conversion of HCO_(3)^(-)to high-value chemicals.

New method of local adjuvant therapy with bicarbonate Ringer’s solution for tumoral calcinosis: A case report

BACKGROUND Tumoral calcinosis is a condition characterized by deposits of calcium phosphate crystals in extra-articular soft tissues,occurring in hemodialysis patients.Calcium phosphate crystals are mainly composed of hydroxyapatite,which is highly infilt-rative to tissues,thus making complete resection difficult.An adjuvant method to remove or resolve the residual crystals during the operation is necessary.CASE SUMMARY A bicarbonate Ringer’s solution with bicarbonate ions(28 mEq/L)was used as the adjuvant.After resecting calcium phosphate deposits of tumoral calcinosis as much as possible,while filling with the solution,residual calcium phosphate deposits at the pseudocyst wall can be gently scraped by fingers or gauze in the operative field.A 49-year-old female undergoing hemodialysis for 15 years had swelling with calcium deposition for 2 years in the shoulders,bilateral hip joints,and the right foot.A shoulder lesion was resected,but the calcification remained and early re-deposition was observed.Considering the difficulty of a complete rection,we devised a bicarbonate dissolution method and excised the foot lesion.After resection of the calcified material,the residual calcified material was washed away with bicarbonate Ringer’s solution.CONCLUSION The bicarbonate dissolution method is a new,simple,and effective treatment for tumoral calcinosis in hemodialysis patients.

Combined effect of bicarbonate and water in photosynthetic oxygen evolution and carbon neutrality

Carbon neutrality is widely concerned and highly valued by many countries.Biosphere has always maintained the balance between oxidized organic substances and assimilated organic matter,resulting in netzero carbon dioxide(CO_(2)) emissions and maintaining its own carbon neutrality.Nature has set a good example for human beings to coordinate oxygen(O_(2)) balance and CO_(2)balance,and achieve carbon neutrality.How does photosynthetic oxygen evolution initiate carbon and water neutrality?My synthesis shows that photo system Ⅱ functions as carbonic anhydrase to catalyze the reaction of CO_(2)hydration under physiological conditions,and CO_(2)hydration coupled with chemical equilibrium,H^(+)+HCO_(3)^(-)→1/2O_(2)+2e^(-)+2H^(+)+CO_(2),occurs in a photosystem Ⅱ corecomplex.Meanwhile,I focused on the revisiting of four classical heavy oxygen(O^(18)) labeling experiments and found that bicarbonate can promote photo synthetic oxygen evolution,and that photo synthetic oxygen evolution can alternately come from bicarbonate and water,not only water.Bicarbonate photolysis and water photolysis account for half of the photo synthetic oxygen evolution respectively,which can well explain the bicarbonate effect,Dole effect and plants’ environmental adaptability.Photosynthetic oxygen evolution initiated the journey of water metabolism and carbon metabolism in nature,which led to the coupling as 1:1(mol/mol) stoichiometric relationship between the reduction of CO_(2)and oxidation of organic carbon,coordinated the evolution of the atmosphere,hydrosphere,lithosphere and biosphere,and realized "carbon neutrality" in the whole Earth system.

New insights into the pathogenesis of primary biliary cholangitis asymptomatic stage

Primary biliary cholangitis(PBC)is a chronic cholestatic progressive liver disease and one of the most important progressive cholangiopathies in adults.Damage to cholangiocytes triggers the development of intrahepatic cholestasis,which progresses to cirrhosis in the terminal stage of the disease.Accumulating data indicate that damage to biliary epithelial cells[(BECs),cholangiocytes]is most likely associated with the intracellular accumulation of bile acids,which have potent detergent properties and damaging effects on cell membranes.The mechanisms underlying uncontrolled bile acid intake into BECs in PBC are associated with pH change in the bile duct lumen,which is controlled by the bicarbonate(HCO3-)buffer system“biliary HCO3-umbrella”.The impaired production and entry of HCO3-from BECs into the bile duct lumen is due to epigenetic changes in expression of the X-linked microRNA 506.Based on the growing body of knowledge on the molecular mechanisms of cholangiocyte damage in patients with PBC,we propose a hypothesis explaining the pathogenesis of the first morphologic(ductulopenia),immunologic(antimitochondrial autoantibodies)and clinical(weakness,malaise,rapid fatigue)signs of the disease in the asymptomatic stage.This review focuses on the consideration of these mechanisms.

Green and sustainably designed intercalation-type anodes for emerging lithium dual-ion batteries with high energy density

Lithium dual-ion batteries(LiDIBs)have attracted significant attention owing to the growing demand for modern anode materials with high energy density.Herein,rust encapsulated in graphite was achieved by utilizing ammonium bicarbonate(ABC)as a template,which resulted in mesoporous Fe3O4embedded in expanded carbon(Fe3O4@G(ABC))via simple ball milling followed by annealing.This self-assembly approach for graphite-encapsulated Fe3O4composites helps enhance the electrochemical performance,such as the cycling stability and superior rate stability(at 3 A/g),with improved conductivity in Li DIBs.Specifically,Fe3O4@G-1:4(ABC)and Fe3O4@G-1:6(ABC)anodes in a half-cell at 0.1 A/g delivered initial capacities of 1390.6 and 824.4 mA h g^(-1),respectively.The optimized anode(Fe3O4@G-1:4(ABC))coupled with the expanded graphite(EG)cathode in Li DIBs provided a substantial initial specific capacity of 260.9 mA h g^(-1)at 1 A/g and a specific capacity regain of 106.3 mA h g^(-1)(at 0.1 A/g)after 250 cycles,with a very high energy density of 387.9 Wh kg^(-1).The strategically designed Fe3O4@G accelerated Li-ion kinetics,alleviated the volume change,and provided an efficient conductive network with excellent mechanical flexibility,resulting in exceptional performance in Li DIBs.Various postmortem analyses of the anode and cathode(XRD,Raman,EDS,and XPS)are presented to explain the intercalation-type electrochemical mechanisms of Li DIBs.This study offers several advantages,including safety,low cost,sustainability,environmental friendliness,and high energy density.

Incomplete distal renal tubular acidosis uncovered during pregnancy:A case report

BACKGROUND Renal tubular acidosis(RTA)is a renal cause of non-anion-gap metabolic acidosis characterized by low urinary ammonia excretion.This condition has a low prevalence,and various congenital and acquired etiologies.To date,only a few cases of idiopathic RTA uncovered during pregnancy have been reported.CASE SUMMARY A previously healthy 32-year-old Korean woman at 30 wk of gestation was admitted to Pusan National University Hospital with preterm labor.At admission,the patient presented with hypokalemia,non-anion-gap metabolic acidosis,and nephrocalcinosis.Distal RTA was diagnosed based on laboratory blood and urine findings and imaging examinations.Various tests,including next-generation gene sequencing panels for nephropathy,were performed to determine the etiology of the disease,which indicated that it was idiopathic.The patient received sodium bicarbonate and potassium chloride supplementation.After 3 wk,she delivered a baby who was subsequently diagnosed with corpus callosum agenesis and colpocephaly.During regular follow-ups for 6 mo postpartum,her hypokalemia and metabolic acidosis were gradually resolved,and medications eventually discontinued.CONCLUSION Herein we describe a case of idiopathic distal RTA discovered during pregnancy.Hypokalemia and metabolic acidosis resolved spontaneously after delivery.

Comparison between Four Types of Buffers for DNA Agarose Gel Electrophoresis

To detect the genome of viruses (in environmental and clinical samples), we use electrophoresis running buffer after PCR reaction. Also, electrophoresis buffers were used widely to separate any DNA molecule. In this paper, we used four types of previously known electrophoresis buffers to compare which is easy for preparation, simple in structure, low cost and good performance in agarose gel electrophoresis. For this, we used two agarose concentration (1%, 2%) and two types of DNA ladder (100 bp, 1 kb) represent both smaller and larger sizes of molecule for each type of buffers, from the result we found in first level both supper buffer and TAE buffer with good performance and in second level we found bicarbonate buffer also with good performance also. Finally, we found the tang buffer cannot pose any electrophoretic activity on DNA agarose gel electrophoresis.

Mechanisms involved in Helicobacter pylori induced duodenal ulcer disease:an overview

Duodenal ulcer (DU) can be developed viaseveral different mechanisms.Hypersecretion ofgastric acid is,however,a common denominator.Amassive hypersecretion of acid can by itself evoke aDU,e.g.in the Zollinger-Ellison syndrome.Irrespective of the mechanism behind thedevelopment of a DU,powerful antisecretorytreatment will heal the ulcer and preventrecurrence.

经胸多普勒超声评价二尖瓣位Sorin Bicarbon双叶机械瓣功能

目的应用多个多普勒参数相结合的方法评价功能正常二尖瓣位Sorin Bicarbon双叶机械瓣。方法选择单独二尖瓣位Sorin Bicarbon双叶机械瓣置换患者56例,多普勒超声测量瓣口及左室流出道的血流速度、压差及速度时间积分;运用PHT和连续方程两种方法分别获得有效瓣口面积(EOA),并用体表面积进行校正(IEOA);计算机械瓣功能指数(PPI)。结果所有患者IEOACON显著小于IEOAPHT(P<0.01),E≤1.9 m/s及PHT<120 ms,83.93%患者TVIMVP/TVILVOT比值<2.2。四种型号机械瓣E及TVIMVP/TVILVOT比值差异无显著性意义,随着瓣膜型号的逐渐增大,PPI逐渐减小,但差别无统计学意义。结论E、PHT及TVIMVP/TVILVOT比值等多普勒参数相结合可较好地评价二尖瓣位Sorin Bicarbon双叶机械瓣功能。

Bicarbonate activation of hydrogen peroxide: A new emerging technology for wastewater treatment

The serious limitations of available technologies for decontamination of wastewater have compelled researchers to search for alternative solutions. Catalytic treatment with hydrogen peroxide, which appears to be one of the most efficient treatment systems, is able to degrade various organics with the help of powerful ·OH radicals. This review focuses on recent progress in the use of bicarbonate activated hydrogen peroxide for wastewater treatment. The introduction of bicarbonate to pollutant treatment has led to appreciable improvements, not only in process efficiency, but also in process stability. This review describes in detail the applications of this process in homogeneous and heterogeneous systems. The enhanced degradation, limited or lack of leaching during heterogeneous degradation, and prolonged catalysts stability during degradation are salient features of this system. This review provides readers with new knowledge regarding bicarbonate, including the fact that it does not always harm pollutant degradation, and can significantly benefit degradation under some conditions.

Passivation process of X80 pipeline steel in bicarbonate solutions

The passivation process of X80 pipeline steel in bicarbonate solutions was investigated using potentiodynamic, dynamic electro-chemical impedance spectroscopy （DEIS）, and Mott-Schottky measurements. The results show that the shape of polarization curves changes with concentration. The critical ＇passive＇ concentration is 0.009 mol/L for X80 pipeline steel in bicarbonate solutions. No anodic current peak exists in solutions when the concentration is lower than 0.009 mol/L, whereas there are one and two anodic current peaks when the concentration ranges from 0.009 to 0.05 mol/L and is higher than 0.1 mol/L, respectively. DEIS measurements show that there exist active dissolution range, transition range, pre-passive range, passive layer formation range, passive range, and trans-passive range for X80 pipeline steel in the 0.1 mol/L solutions. The results of DEIS measurements are in complete agreement with the potentiodynamic diagram. An equivalent circuit containing three sub-layers is used to explain the Nyquist plots in the passive range. Analyses are well made for explaining the corresponding fitted capacitance and impedance. The Mott-Schottky plots show that the passive film of X80 pipeline steel is an n-type semiconductor, and capacitance measurements are in good accordance with the results of DEIS experiment.

Cholangiocyte anion exchange and biliary bicarbonate excretion

Primary canalicular bile undergoes a process of fluidization and alkalinization along the biliary tract that is influenced by several factors including hormones, innervation/neuropeptides, and biliary constituents. The excretion of bicarbonate at both the canaliculi and the bile ducts is an important contributor to the generation of the so-called bile-salt independent flow. Bicarbonate is secreted from hepatocytes and cholangiocytes through parallel mechanisms which involve chloride efflux through activation of Cl- channels, and further bicarbonate secretion via AE2/SLC4A2-mediated Cl-/HCO3- exchange. Glucagon and secretin are two relevant hormones which seem to act very similarly in their target cells （hepatocytes for the former and cholangiocytes for the latter）. These hormones interact with their specific G protein-coupled receptors, causing increases in intracellular levels of cAMP and activation of cAMP-dependent Cl- and HCO3- secretory mechanisms. Both hepatocytes and cholangiocytes appear to have cAMP-responsive intracellular vesicles in which AE2/SLC4A2 colocalizes with cell specific Cl- channels （CFTR in cholangiocytes and not yet determined in hepatocytes） and aquaporins （AQP8 in hepatocytes and AQP1 in cholangiocytes）, cAMP-induced coordinated trafficking of these vesicles to either canalicular or cholangiocyte lumenal membranes and further exocytosis results in increased osmotic forces and passive movement of water with net bicarbonate-rich hydrocholeresis.

Stress corrosion cracking of X80 pipeline steel exposed to high pH solutions with different concentrations of bicarbonate

Susceptibilities to stress corrosion cracking （SCC） of X80 pipeline steel in high pH solutions with various concentrations of HC03 at a passive potential of-0.2 V vs. SCE were investigated by slow strain rate tensile （SSRT） test. The SCC mechanism and the effect of HC03 were discussed with the aid of electrochemical techniques. It is indicated that X80 steel shows enhunced susceptibility to SCC with the concentration of HCO3 increasing from 0.15 to 1.00 mol/L, and the susceptibility can be evaluated in terms of current density at -0.2 V vs. SCE. The SCC behavior is controlled by the dissolution-based mechanism in these circumstances. Increasing the concentration of HCO3 not only increases the risk of rupture of passive films but also promotes the anodic dissolution of crack tips. Besides, little susceptibility to SCC is found in dilute solution containing 0.05 mol/L HCO3 for X80 steel. This can be attributed to the inhibited repassivation of passive films, manifesting as a more intensive dissolution in the non-crack tip areas than at the crack tips.

Challenges and opportunities for using formate to store, transport, and use hydrogen

In this perspective article,the synthesis and thermodynamic properties of aqueous solutions of formate salts(FS,HCO2-)are described in relationship to the concept of H2carriers.The physiochemical properties of solid FS,aqueous formate solutions,and aqueous bicarbonate solutions set the limitations for storage capacity,deliverable capacity,and usable H2capacity of these H2carriers,respectively.These parameters will help in the design of systems that use H2carriers for storage and transport of H2for fuel cell power applications.FS,as well as admixtures with formic acid(FA,H2CO2),have potential to address the goals outlined in the U.S.Department of Energy’s H2@scale initiative to store in chemical bonds a significant quantity of energy(hundreds of megawatts)obtained from large scale renewable resources.

Effects of nuclei ambiguus and dorsal motor nuclei of vagus on gastric H^+ and HCO_3^- secretion in rats

AIM: To determine the effects of electrical stimulation of nucleus ambiguus (NA) and dorsal motor nuclei of vagus (DMV) on gastric acid and bicarbonate secretion in rats. METHODS: NA and DMV in rats were electrically stimulated. Pylorus ligation or esophagus perfusion was used to collect the gastric secretion. The titratable H+ quantum, H+ concentration, HCO3- secretion quantum were measured. RESULTS: Electrical stimulation of NA had no effects on the volume of gastric juice, titratable acidity and acid concentration, but elicited a pronounced increase in the total bicarbonate. However, electrical stimulation of DMV significantly increased the titratable acidity, the volume of gastric juice and the acid concentration. Similarly, electrical stimulation of either NA or DMV decreased the respiratory frequency and sinus bradycardia. CONCLUSION: NA in rats can not control the secretion of gastric acid but the secretion of bicarbonate in gastric juice, while DMV controls the secretion of gastric acid.

Quantification of photosynthetic inorganic carbon utilisation via a bidirectional stable carbon isotope tracer

The amount of bicarbonate utilised by plants is usually ignored because of limited measurement methods. Accordingly, this study quantified the photosynthetic assimilation of inorganic carbon （COe and HCO3-） by plants. The net photosynthetic COa assimilation （PN）, the photosynthetic assimilation of CO2 and bicarbonate （PN＇）, the proportion of increased leaf area （lEA） and the stable carbon isotope composition （δ13C） of Orychophragmus violaceus （Ov） and Brassica juncea （B j） under three bicarbonate levels （5, 10 and 15 mm NaHCO3） were examined to determine the relationship among PN, PN＇ and fLA. PN＇, not PN, changed synchronously with fLA. Moreover, the proportions of exogenous bicarbonate and total bicarbonate （including exogenous bicarbonate and dissolved CO2-generated bicarbonate） utilised by Ov were 2.27 % and 5.28 % at 5 mm bicarbonate, 7.06 % and 13.28 % at 10 mm bicarbonate, and 8.55 % and 17.31% at 15 mm bicarbonate, respectively. Meanwhile, the propor- tions of exogenous bicarbonate and total bicarbonate uti- lised by Bj were 1.77 % and 3.28 % at 5 mm bicarbonate, 2.11% and 3.10 % at 10 mm bicarbonate, and 2.36 % and 3.09 % at 15 mm bicarbonate, respectively. Therefore, the dissolved CO2-generated bicarbonate and exogenous bicarbonate are important sources of inorganic carbon for plants.

Effect of HCO_3^- concentration on CO_2 corrosion in oil and gas fields

The effect of HCO3^- concentration on CO2 corrosion was investigated by polarization measurement of potentiodynamic scans and weight-loss method, Under the conditions of high pressure and high temperature, the corrosion rate of steel X65 decreased with the increase of HCO3^- concentration, while pH of solution increased. SEM, EDS, and XRD results of the corrosion scales indir cated that the typical FeCO3 crystallite was found at low HCO3^- concentration but Ca（Fe,Mg）（CO3）2 was found at high HCO3^- con- centration. Ca^2＋ and Mg^2＋ are precipitated preferential to Fe^2＋ at high pH value. Potentiodynamic polarization curves showed that the cathodic current density decreases with the increase of HCO3^- concentration at low HCO3^- concentration. When the HCO3^- concentration reaches 0.126 mol/L, increasing HCO3^- concentration promotes cathodic reactions. Anodic behavior is an active process at low HCO3^- concentration and the anodic current density decreases with the increase of HCO3^- concentration. An evident active-passive behavior is exhibited in anodic process at 0.126 mol/L HCO3^-.