Thermally decarboxylated sodium bicarbonate:Interactions with water vapour,calorimetric study

Isothermal titration calorimetry （ITC） was used to study interactions between water vapour and the surface of thermally converted sodium bicarbonate （NaHCO3）. The decarboxyla- tion degree of the samples was varied from 3% to 35% and the humidity range was 54-100%. The obtained enthalpy values were all exothermic and showed a positive linear correlation with decarboxylation degrees for each humidity studied. The critical humidity, 75% （RHo）, was determined as the inflection point on a plot of the mean-AH kJ/mole Na2CO3 against RH. Humidities above the critical humidity lead to complete surface dissolution. The water uptake （m） was determined after each calorimetric experiment, complementing the enthalpy data. A mechanism of water vapour interaction with decarboxylated samples, including the formation of trona and Wegscheider＇s salt on the bicarbonate surface is proposed for humidities below RHo.

A comparative in vitro study on the cerumenolytic effect of docusate sodium versus 2.5%sodium bicarbonate using UVevisible absorption spectroscopy

Objective:To compare cerumenolytic effects of docusate sodium and of 2.5%sodium bicarbonate-In vitro study;observe characteristics of the solution,using ultravioletevisible(UV/Vis)spectroscopy,and measurement of cholesterol levels.Methods:Samples of human cerumen were mixed to form a relatively homogenous paste.Samples of about 500mg were weighed and packed at the bottom of the test tubes.To each tube was added 1.5 ml of either docusate sodium or 2.5%sodium bicarbonate.Tubes were incubated at 36.4C in a water bath for 15,30 or 60 min.Following incubation,the supernatant solution was pipetted into a cuvette.The cerumenolytic efficacy was defined as the absorbance(recorded at 350 nm and 400 nm)of the solutions.Results were the average of three replicates.A cholesterol level of each sample was then determined to confirm the result.Results:Turbidity was much greater in tubes containing 2.5%sodium bicarbonate,indicating dissolution of cerumen.Mean difference of absorbance values measured at 350 nm and 400 nm after 15,30,60 min digestions were 1.93[95%CI 1.49e2.38,p-value<0.001]and 1.81[95%CI 1.21e2.41,p-value<0.001],respectively.Furthermore,levels of cholesterol were greater in tubes containing 2.5%sodium bicarbonate solution after digestion than in tubes containing docusate sodium;11 mg/dl[95%CI 1.47e24.14,pvalue?0.083]Conclusion:Both spectrophotometric and cholesterol level assessments suggest that 2.5%sodium bicarbonate has a higher cerumenolytic effect than docusate sodium.In other words,cerumen can be dissolved in 2.5%sodium bicarbonate much better than docusate sodium in a time-dependent manner.

Expression and Purification of Hydrophilic Domains of Bovine Anion Exchanger,Member 1 and Electrogenic Sodium Bicarbonate Cotransporter 1

[ Objective] To express and purify the intracellular hydrophilic domains of bovine membrane carrier proteins：anion exchanger, member 1 （AE1） and electregenic sodium bicarbonate cotransporter 1 （NBCel）, which were associated with bicarbonate ion transport. [ Method] The hydrophilic domains of bovine AE1 and NBCel were amplified by PCR and inserted into the prokaryotic expression vector pET-28a, respectively. The recombinant plasmids were transformed into the expression strain E. coli BL21 （DE3） and then induced by IPTG. The expressed proteins were purified by nickel ion affinity chromatography and analyzed by 15% SDS-PAGE. [Result] The hydrophilic domains of bovine AE1 and NBCel were amplified respectively by PCR and expressed by prokaryotic expression system with the induction of IPTG. They were mainly expressed in the cyto- plasm of E. coli and high-purity was achieved by nickel ion affinity chromatography. [Condusion] The expression of the hydrophilic domains of bovine AE1 and NBCel provides a major exit route for preparation of antibodies and the regulatory mechanisms of carrier proteins.

Effect of sodium bicarbonate solution on methyltrimethoxysilane-derived silica aerogels dried at ambient pressure

Here we present an economical ambient pressure drying method of preparing monolithic silica aerogels from methyltrimethoxysilane precursor while using sodium bicarbonate solution as the exchanging solvent.We prepared silica aerogels with a density and a specific surface area of 0.053 g·cm^(-3) and 423 m^(2)·g^(-1) respectively.The average pore diameter of silica aerogels is 23 nm as the pore specific volume is 1.11 cm^(3)·g^(-1),Further,the contact angle between water droplet and the surface of silica aerogels in specific condition can be as high as 166°,which indicates a super-hydrophobic surface of aerogels.

Sodium bicarbonate, an inorganic salt and a potential active agent for cancer therapy

Cancer is a serious threat to humans due to its high mortality. The efforts to fully understand cancer and to fight against it have never been stopped. The traditional therapies, such as surgery, radiotherapy and chemotherapy, are useful but cannot meet the increasing demands of patients. As such, novel approaches against cancer are urgently required. It has been found that the acidic tumor microenvironment plays important roles in promoting the cancer progression. In recent years, sodium bicarbonate(NaHCO_(3)), a simple inorganic salt, has been found to be able to reverse the p H of tumor microenvironment and inhibit the invasion, metastasis, immune evasion, drug resistance and hypoxia of tumor cells. Thus, NaHCO_(3)-based therapy is a potential approach for the treatment of cancer, and the related studies have been increasingly reported. Herein, we aim to provide a comprehensive understanding of the acidic tumor microenvironment and summarize the applications and mechanisms of Na HCO_(3)in cancer therapy. The combination of Na HCO;with chemotherapy, immunotherapy or nanoparticles systems is discussed. In addition, the concerns of Na HCO_(3)in clinical use and the potential ways to use Na HCO_(3)for cancer therapy are also discussed.

Preliminary results of gentamycin combined with sodium bicarbonate for prevention of irinotecan-induced diarrhea

The aim of this paper was to observe the clinical effect of gentamycin combined with sodium bicarbonate for the prevention of irinotecan-induced diarrhea.A total of 98 patients with stage IV cancers were recruited and divided into a prevention group(52 patients)and a control group(46 patients).All patients received the chemotherapy including irinotecan.The prevention group received gentamycin and sodium bicarbonate before the use of irinotecan for 4 days;the control group did not receive any prevention.The use of gentamycin and sodium bicarbonate resulted in signifi-cantly higher stool pH(P<0.001),while the incidence of diarrhea by irinotecan was reduced(prevention group 13.70%versus control group 34.83%;P<0.001).Genta-mycin combined with sodium bicarbonate appears to be useful in preventing the diarrhea induced by irinotecan and reducing the dosage of loperamide andfluid replacement.

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.

Isolation of a novel strain of Cyanobacterium sp.with good adaptation to extreme alkalinity and high polysaccharide yield

The use of high alkaline medium is a feasible way to provide carbon source and prevent biological contamination for the outdoor cultivation of alkaliphilic microalgae and cyanobacteria.A novel cyanobacterial strain was isolated from the open pond of a marine green alga(Picochlorum sp.SCSIO-45015,Sanya,Hainan)and identified as Cyanobacterium sp.SCSIO-45682.The effects of initial sodium bicarbonate(NaHCO_(3))concentrations on the growth and biochemical composition of Cyanobacterium sp.SCSIO-45682 were investigated.The results demonstrated that Cyanobacterium sp.SCSIO-45682 had good adaptation to 16.8-g/L NaHCO_(3)(the same concentration of NaHCO_(3) used in Zarrouk medium for Spirulina).Moreover,the yields of biomass,polysaccharide,chlorophyll a(chl a),and phycocyanin increased under high NaHCO_(3) concentrations.The maximum final biomass concentration of 2.5 g/L was observed at 8.4-g/L NaHCO_(3),while the highest intracellular total saccharide content of 49.2%of dry weight(DW)and exopolysaccharide(EPS)concentration of 93 mg/L were achieved at the NaHCO_(3) concentration of 16.8 g/L.The crude protein content declined under high NaHCO_(3) concentrations,which provide a possible explanation for the accumulation of polysaccharide.This study shows a good potential of alkaliphilic Cyanobacterium sp.SCSIO-45682 as a polysaccharide feedstock.

Introduction and Influence of Water in the Preparation of Crosslinked PVC Foam by Isocyanate

In the preparation process of crosslinked polyvinyl chloride(c-PVC)foam by isocyanate,the formulated mixture is generally required to be carried out under the condition of isolated water,so as to avoid the mixing difficulties caused by the reaction between the introduced water and isocyanate.In this paper,NaHCO_(3) was added to the mixture to indirectly introduce water into the system,and the effects of NaHCO_(3) on the cell structure and curing time of c-PVC foam were investigated.The results showed that NaHCO_(3) not only played a role of foaming agent,but also was a good nucleating agent for cells.At the same time,the introduction of NaHCO_(3) held back the exudation of modified diphenylmethane-4,4'-diisocyanate(MDI)on the cell wall.The effects of NaHCO_(3) on the cell structure and aggregation structure of c-PVC foam were studied by thermogravimetric analysis,infrared spectroscopy and scanning electron microscopy.The results showed that decomposition of NaHCO_(3) occurred during the molding stage,which made small amount of MDI react with water to form polyurea,improved the compatibility of MDI with PVC and inhibited the exudation of MDI.

NaHCO_(3)-induced porous PbI_(2) enabling efficient and stable perovskite solar cells

Driven by their many unique features,perovskite solar cells(PSCs)have become one of the most promising candidates in the photovoltaic field.Two-step preparation of perovskite film is advantageous for its higher stability and reproducibility compared to the one-step method,which is more suitable for practical application.However,the incomplete conversion of the dense lead iodide(PbI_(2))layer during the sequential spin-coating of formamidinium/methylammonium(FA^(+)/MA^(+))organic amine salts severely affect the performance of PSCs.Herein,sodium bicarbonate(NaHCO_(3))is used to induce the formation of porous PbI_(2),which facilitates the penetration of the FA^(+)/MA^(+)ions and the formation of a perovskite film with high crystallinity and large grain microstructure.Meanwhile,the introduction of Na^(+)not only improves the energetic alignment of the PSC,but also increases the conductivity via p-doping.As a result,the optimized NaHCO_(3)-modified PSC achieves a champion power conversion efficiency of 24.0% with suppressed hysteresis.Moreover,the significant reduction in defect density and ion migration as well as a mild alkaline environment enhance the stability of device.The unencapsulated NaHCO_(3)-modified PSCs maintain over 90% of their original efficiency upon storage in ambient air(30%–40% relative humidity)for 2160 h.We have demonstrated an ingenious strategy for controlling the quality of perovskite and improving the performance of device by low-temperature foaming of simple inorganic molecules of NaHCO_(3).

Contraception with RISUG and functional reversal through DMSO and NaHCO3 in male rabbits

The study aimed to evaluate reversal of short- and long-term vas occlusion with reversible inhibition of sperm under guidance （RISUG） using dimethyl sulfoxide （DMSO） and sodium bicarbonate （NaHCO3） in male rabbits （Oryctolagus cuniculus）. Animals were divided into seven groups containing five animals each. Fortnightly, semen analysis revealed that sperm concentration and output steadily declined after vas occlusion and complete azoospermia was attained at 30-60 days postinjection. Spermatozoa reappeared at 60-75 days of reversal and normozoospermia was noticed between 135 days and 150 days in the reversal groups. All spermatozoa were found nonmotile prior to azoospermia and a gradual recovery in sperm motility was observed between 105 days and 135 days of reversal. A significant decline in viability of sperms was noticed during vas occlusion up to 30-60 days which recovered at 60-75 days postreversal and normalized by 75-105 days in the reversal groups. A significant enhancement in the sperm abnormalities was recorded in all vas occluded animals as well as those in initial periods of reversal. Other parameters, namely, semen volume, ejaculation time, pH, color, and consistency, remained unaltered during all phases of the study. Fertility test, at the intervals of 15 days, demonstrated that animals exhibited complete sterility during the entire period of vas occlusion. A gradual recovery in fertility was observed with the appearance of spermatozoa following vas occlusion reversal and 100% fertility was observed following 135-150 days of reversal. F, progeny of reversed animals was found normal. The results suggest that reversal with DMSO or NaHCO3 is feasible, with normal progeny, following short- and long-term contraception.