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 proce...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.展开更多
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 electroche...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.展开更多
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...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.展开更多
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 diox...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.展开更多
The effect of zinc(Zn) deficiency and excessive bicarbonate on the allocation and exudation of organic acids in plant organs(root, stem, and leaf) and root exudates of two Moraceae plants(Broussonetia papyrifera and M...The effect of zinc(Zn) deficiency and excessive bicarbonate on the allocation and exudation of organic acids in plant organs(root, stem, and leaf) and root exudates of two Moraceae plants(Broussonetia papyrifera and Morus alba) were investigated. Two Moraceae plants were hydroponically grown and cultured in nutrient solution in four different treatments with 0.02 mM Zn or no Zn,combined with no or 10 mM bicarbonate. The variations of organic acids in different plant organs were similar to those of root exudates in the four treatments except B. papyrifera, which was in a treatment that was a combination of 0.02 mM Zn and no bicarbonate. The response characteristics in the production, translocation, and allocation of organic acids in the plant organs and root exudates varied with species and treatments. Organic acids in plant organs and root exudates increased under Zn-deficient conditions,excessive bicarbonate, or both. An increase of organic acids in the leaves resulted in an increase of root-exuded organic acids. B. papyrifera translocated more oxalate and citrate from the roots to the rhizosphere than M. alba under the dual influence of 10 mM bicarbonate and Zn deficiency. Organic acids of leaves may be derived from dark respiration and photorespiration. By comparison, organic acids in stems, roots, and root exudates may be derived from dark respiration and organic acid translocation from the leaves. These results provide evidence for the selective adaptation of plants to environments with low Zn levels or high bicarbonate levels such as a karst ecosystem.展开更多
Diabetic ketoacidosis(DKA) is a severe and toocommon complication of uncontrolled diabetes mellitus. Acidosis is one of the fundamental disruptions stemming from the disease process, the complications of which are pot...Diabetic ketoacidosis(DKA) is a severe and toocommon complication of uncontrolled diabetes mellitus. Acidosis is one of the fundamental disruptions stemming from the disease process, the complications of which are potentially lethal. Hydration and insulin administration have been the cornerstones of DKA therapy; however, adjunctive treatments such as the use of sodium bicarbonate and protocols that include serial monitoring with blood gas analysis have been much more controversial. There is substantial literature available regarding the use of exogenous sodium bicarbonate in mild to moderately severe acidosis; the bulk of the data argue against significant benefit in important clinical outcomes and suggest possible adverse effects with the use of bicarbonate. However, there is scant data to support or refute the role of bicarbonate therapy in very severe acidosis. Arterial blood gas(ABG) assessment is an element of some treatment protocols, including society guidelines, for DKA. We review the evidence supporting these recommendations. In addition, we review the data supporting some less cumbersome tests, including venous blood gas assessment and routine chemistries. It remains unclear that measurement of blood gas pH, via arterial or venous sampling, impacts management of the patient substantially enough to warrant the testing, especially if sodium bicarbonate administration is not being considered. There are special circumstances when serial ABG monitoring and/or sodium bicarbonate infusion are necessary, which we also review. Additional studies are needed to determine the utility of these interventions in patients with severe DKA and pH less than 7.0.展开更多
Photosynthesis is crucial to the reduction of carbon dioxide in the atmosphere.The key enzyme of photosynthesis,Ribulose-1,5-bisphosphate carboxylase/oxygenase(Rubisco),has two mutably competing substrates,CO2 and O2....Photosynthesis is crucial to the reduction of carbon dioxide in the atmosphere.The key enzyme of photosynthesis,Ribulose-1,5-bisphosphate carboxylase/oxygenase(Rubisco),has two mutably competing substrates,CO2 and O2.It has features of carboxylase and oxygenase.Rubisco performs the function of carboxylase to reduce inorganic carbon to form organic substances,which precondition is that more carbon dioxide accumulates around it.Carbon dioxide concentrating mechanisms(CCMs)are vital to cope with the limit of carbon dioxide.Various bicarbonate use pathway has a differential contribution to inorganic carbon assimilation.Bicarbonate transport,extracellular bicarbonate dehydration,or H+-ATPase-driven bicarbonate uptake,which induced CCMs,can support a considerable share of photosynthesis in photosynthetic organisms.However,CCMs in thylakoid membranes may be the most important.The CCMs occurred in the plasma membrane were secondary,evolutionary,and inducible,while CCMs coupled with photosynthetic oxygen evolution in thylakoid membranes,were primitive,major,and indispensable.A hypothetical schematic model of CCMs occurred in the plasma membrane and thylakoid membranes being proposed.展开更多
AIM: To explore whether serum bicarbonate at admission to intensive care unit(ICU) predicted development of acute kidney injury(AKI).METHODS:We studied all patients admitted to our ICU over a 2 year period(February 20...AIM: To explore whether serum bicarbonate at admission to intensive care unit(ICU) predicted development of acute kidney injury(AKI).METHODS:We studied all patients admitted to our ICU over a 2 year period(February 2010 to 2012).The ICU has a case mix of medical and surgical patients excluding cardiac surgical,trauma and neurosurgical patients.We analysed 2035 consecutive patients admitted to ICU during the study period.Data were collected by two investigators independently and in duplicate using a standardised spread sheet to ensure accuracy.Ambiguous data were checked for accuracy where indicated.AKI was defined using the Kidney Disease Improving Global Outcomes criteria.Patients were divided into two groups;patients who developed AKI or those who did not,in order to compare the baseline characteristics,and laboratory and physiologic data of the two cohorts.Regression analysis was used to identify if serum bicarbonate on admission predicted the development of AKI.RESULTS:Of 2036 patients 152(7.5%)were excluded due to missing data.AKI developed in 43.1%of the patients.The AKI group,compared to the nonAKI group,was sicker based on their lower systolic,diastolic and mean arterial pressures and a higher acutephysiology and chronic health evaluation(APACHE)Ⅲand SAPSⅡscores.Moreover,patients who developed AKI had more co-morbidities and a higher proportion of patients who developed AKI required mechanical ventilation.The multi-regression analysis of independent variables showed that serum bicarbonate on admission(OR=0.821;95%CI:0.796-0.846;P<0.0001),APACHEⅢ(OR=1.011;95%CI:1.007-1.015;P<0.0001),age(OR=1.016;95%CI:1.008-1.024;P<0.0001)and presence of sepsis at ICU admission(OR=2.819;95%CI:2.122-23.744;P=0.004)were each significant independent predictors of AKI.The area under the ROC curve was 0.8(95%CI:0.78-0.83),thereby demonstrating that the predictive model has relatively good discriminating power for predicting AKI.CONCLUSION:Serum bicarbonate on admission may independently be used to make a diagnosis of AKI.展开更多
If the photosynthetic organisms assimilated only CO_(2) in the Archean atmosphere,hydroxide ion in the Archean seawater would not increase.If plants would not consume bicarbonate as a direct substrate during photosynt...If the photosynthetic organisms assimilated only CO_(2) in the Archean atmosphere,hydroxide ion in the Archean seawater would not increase.If plants would not consume bicarbonate as a direct substrate during photosynthesis,it is difficult to explain the evolution of Earth's environment.To date,it is generally accepted that photosynthetic O_(2) evolution of plants come from water photolysis.However,it should be debated by evaluating the effect of bicarbonate in photosynthetic O_(2) evolution,analyzing the role of carbonic anhydrase(CA) in photosynthetic O_(2) evolution,and the relationship between thylakoid CA and photosynthetic O_(2) evolution.In the paper,I propose that bicarbonate is directly used as substrate to participate in photosynthetic O_(2) evolution.The rationality of bicarbonate photolysis of plants is discussed from the thermodynamics and evolution of Earth's environment.The isotopic evidence that bicarbonate is not the direct substrate of photosynthetic O_(2) release is reexamined,and the new explanation of bicarbonate photolysis in photosynthetic O_(2) evolution is proposed.展开更多
Because the use of phosphates has being recently diminished in meat industry due to the nutritional drawbacks of phosphates, some researchers started to evaluate sodium bicarbonate as phosphate replacer in meat produc...Because the use of phosphates has being recently diminished in meat industry due to the nutritional drawbacks of phosphates, some researchers started to evaluate sodium bicarbonate as phosphate replacer in meat products. The aim of this study was to evaluate the effect of different temperature combinations of dry air-cooking treatments (Air and Core temperatures: 160 - 76, 160 - 80, 200 - 76 and 200℃ - 80℃, respectively) on chemical composition, texture properties, water activity, freezable water and bound water, color, pH, and water binding capacity of phosphate and bicarbonate-marinated chicken breast. A batch of 24 h post-mortem broiler breast meat of 80 fillets was divided into two groups of marination treatments (0.3% sodium bicarbonate n = 40, 0.3% sodium tripolyphosphate n = 40) and was vacuum tumbled (45 min, ?0.95 mbar, 20 rpm). Different temperature-combinations cooking treatments significantly modified the chemical composition. Bicarbonate marinated fillets showed higher ability to retain water (67.3% vs. 65.7%, P 0.05) during severe heat treatment and lower cook losses (30.7% vs. 33.4%, P 0.05) when compared with phosphate-marinated fillets. The effect of changing the cooking temperatures on Texture Profile Analysis (hardness, cohesiveness, gumminess, springiness, and chewiness) was more tangible in phosphate marinated fillets than bicarbonate. Bicarbonate-marinated fillets showed significant differences in the percentage of bound water, latent heat, and water activity after cooking in comparison to phosphate-marinated fillets. The results of this study revealed that phosphate-marinated fillets interacted with heat treatments in different patterns in comparison with bicarbonate-marinated fillets.展开更多
Objectives: Recent reports on venous blood gas analysis have shown that venous bicarbonate concentration is useful in the evaluation of the body acid-base status. Most of these reports have been based on the Bland-Alt...Objectives: Recent reports on venous blood gas analysis have shown that venous bicarbonate concentration is useful in the evaluation of the body acid-base status. Most of these reports have been based on the Bland-Altman analysis comparing arterial and venous blood gas values. We intended to elucidate any factors that decrease the agreement between venous and arterial bicarbonate concentrations, which might impair the usefulness of venous blood gas analysis. Methods: Healthy volunteers and patients with various diseases (n = 141) were evaluated by simultaneous arterial and venous blood sampling and Bland-Altman analysis. The venous-arterial bicarbonate concentration difference was compared between healthy volunteers and untreated respiratory alkalosis patients. Intentional hyperventilation (30 or 60 breaths/min, for 3 min) was also performed on 6 healthy volunteers and the venous-arterial bicarbonate concentration difference was evaluated. Results: The relative average bias in bicarbonate concentration was 2.00 mEq/l with venous bicarbonate higher than arterial bicarbonate with 95% limits of agreement of ±4.15 mEq/l. Hyperventilation challenges increased the venous-arterial bicarbonate concentration difference in an intensity-dependent manner. The venous-arterial bicarbonate concentration difference was higher in untreated respiratory alkalosis patients than in healthy volunteers (P Conclusion: Although venous bicarbonate may be useful to evaluate the body acid-base status, hyperventilation increases the venous-arterial bicarbonate concentration difference. Physicians should keep this phenomenon in mind.展开更多
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 chole...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.展开更多
This report aims to look at the role of Sodium bicarbonate as a potent Ergogenic aid and its role in improving the performance of athletes. It includes the mechanism of action of sodium bicarbonate during high-intensi...This report aims to look at the role of Sodium bicarbonate as a potent Ergogenic aid and its role in improving the performance of athletes. It includes the mechanism of action of sodium bicarbonate during high-intensity exercise. The report also shows the various types of athletes who can be benefited from sodium bicarbonate loading, evidences for improvement in performance, conflicting evidences, recommended dosages and side-effects for bicarbonate loading.展开更多
In this study, we investigated the effect of sodium bicarbonate (NaHCO3) supplementation at a dose of 0.2 g·kg−1 40 min before an exercise on intermittent endurance performance and gastrointestina...In this study, we investigated the effect of sodium bicarbonate (NaHCO3) supplementation at a dose of 0.2 g·kg−1 40 min before an exercise on intermittent endurance performance and gastrointestinal distress. The participants were six healthy male students of a university. The Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2) was used for the evaluation of intermittent endurance. The participants ingested water (Cont) or NaHCO3 independently at three timings. After drinking water, the Yo-Yo IR1 was performed for 2 min as warm-up. After resting for 5 min, the Yo-Yo IR2 was initiated. The measurement items were exercise distance, nutrition intake, biochemical test results, and blood gas analysis findings. The participants who ingested NaHCO3 had a 14% extended distance than those who ingested Cont, and 2/3 of those who took NaHCO3 showed a better motor performance. No significant difference was observed between the participants who took Cont and NaHCO3 in terms of pH level at baseline, and the NaHCO3 level was significantly higher during pre- and post-exercise (p 3 in terms of bicarbonate ion level at baseline, and the NaHCO3 level was significantly higher during pre- and post-exercise (p 3 at a low dose (0.2 g·kg−1), their exercise ability during an intermittent endurance test has improved. Furthermore, when digestive absorption is considered, eating a meal in advance may be able to suppress the onset of gastrointestinal distress.展开更多
Background and aims: we aimed to detect the outcome values of adding fentanyl, dexamethasone and sodium bicarbonate to mixture of local anesthetic in peribulbar block for vitreoretinal surgery. Methods: 120 adult ASA ...Background and aims: we aimed to detect the outcome values of adding fentanyl, dexamethasone and sodium bicarbonate to mixture of local anesthetic in peribulbar block for vitreoretinal surgery. Methods: 120 adult ASA I & II patients, admitted for vitreoretinal surgery under peribulbar block were included in this comparative study. This study included 4 groups: Group I: (30) patients using a mixture of 1 ml normal saline, 4 ml lidocaine 2% plus 4 ml from bupivacaine 0.5% 20 ml vial containing hyaluronidase 1500 IU. Group II: (30) patients using a mixture of 1 ml of sodium bicarbonate (from 1 ml sodium bicarbonate 8.4% diluted in 10 ml normal saline), 4 ml lidocaine 2% plus 4 ml from bupivacaine 0.5% 20 ml vial containing hyaluronidase 1500 IU. Group III: (30) patients using a mixture of 1 ml fentanyl 20 μg (from a mixture of fentanyl 100 μg diluted in 5 ml normal saline), 4 ml lidocaine 2% plus 4 ml from bupivacaine 0.5% 20 ml vial containing hyaluronidase 1500 IU. Group IV: (30) patients using a mixture of 1 ml of 4 mg dexamethasone (1 ampoule = 8 mg/2 ml), 4 ml lidocaine 2% plus 4 ml from bupivacaine 0.5% 20 ml vial containing hyaluronidase 1500 IU. We measured the onset and duration of anesthesia, IOP, eyelid and global akinesia, postoperative pain by numerical pain rating scale, first analgesic requirement and postoperative side effects. Results: No significant differences were detected among the four groups as respect to age, sex and the intraocular pressure (IOP) before the anesthesia block. While the intraocular pressure (IOP) after the anesthesia block there was a significant difference, as IOP was markedly decreased postoperatively in group II compared with other groups. As regard to the onset & duration of anesthesia there was significant difference among all groups, there was rapid onset and prolonged duration of anesthesia in group III compared with other groups (1.77 ± 0.63 & 5.03 ± 0.89) respectively. As regard the onset of lid akinesia there was significant difference among the four groups with better outcome in group III, as in group III represented the most rapid onset of lid akinesia. As respecting to the onset of global akinesia there was significant difference among the four groups. There was better outcome in group III as it represented more rapid onset of global akinesia compared with other groups. There were significant differences among the four groups as regard postoperative pain all over 6 hours, better results were in group III (0.27 ± 0.69) compared with group I (2.23 ± 1.17), group II (2.00 ± 1.70), group IV (0.67 ± 0.71). As regarding to the first time for analgesic requirement there were significant differences among groups, there was no request for analgesia with better outcome in group III with increasing need to the analgesic medication in group I compared to group II and group IV. As regard side effects postoperatively there were few side effects in all groups with few numbers of cases in groups III only one patient. Although these differences in number of patients are not significant among the four groups. Conclusion: Addition of sodium bicarbonate to local anesthetic mixture was the best way in lowering the IOP other than other groups and addition of fentanyl to local anesthesia provided more rapid onset and duration of anesthesia, more rapid onset and duration for lid and global akinesia, less pain, less analgesic requirement and minimal side effects than the other groups.展开更多
AIM To examine possible alterations in acid-base parameters in patients switching from lanthanum carbonate(LanC) to sucroferric oxyhydroxide(SFOH). METHODS Fifteen stable hemodialysis patients were switched from LanC ...AIM To examine possible alterations in acid-base parameters in patients switching from lanthanum carbonate(LanC) to sucroferric oxyhydroxide(SFOH). METHODS Fifteen stable hemodialysis patients were switched from LanC to SFOH. Only nine continued on SFOH, three returned to LanC and the other three switched to sevelamer carbonate. The later six patients served as a control group to the SFOH group of nine patients. Blood was sampled on the 3-d and the last 2-d interval of the week prior to switching and six weeks after. Bicarbonate levels(HCO_3^-), pH, pO_2, pCO_2 were measured, and the mean of the two measurements(3-d and 2-d interval) was calculated. RESULTS Comparing pre-switching to post-switching measurementsin the SFOH group, no statistically significant differences were found in any of the parameters studied. The mean pre-switching HCO_3^-was 22.41 ± 1.66 mmol/L and the mean post-switching was 22.62 ± 2.25 mmol/L(P = 0.889). Respectively, the mean pH= 7.38 ± 0.03 vs 7.39 ± 0.03(P = 0.635), mean pCO_2= 38.41 ± 3.29 vs 38.37 ± 3.62 mmHg(P = 0.767), and Phosphate = 1.57 ± 0.27 vs 1.36 ± 0.38 mmol/L(P = 0.214). There were not any significant differences when we performed the same analyses in the control group or between the SFOH group and control group. No correlations were found, either between pre-switching LanC daily dose or between postswitching daily dose of the new binder and the measured parameters.CONCLUSION In our small study, switching from LanC to SFOH did not have any significant effect on blood bicarbonate levels and gas analysis, indicating that there is no need to change hemodialysis prescription regarding these parameters.展开更多
The anti-cancer therapy of irinotecan (CPT-11) is often limited due to severe late-onset diarrhea. Because the higher toxic form of CPT-11/its active metabolite (SN-38) is produced at acidification, the usefulness of ...The anti-cancer therapy of irinotecan (CPT-11) is often limited due to severe late-onset diarrhea. Because the higher toxic form of CPT-11/its active metabolite (SN-38) is produced at acidification, the usefulness of oral sodium bicarbonate treatment against the CPT-11/SN-38-induced intestinal injuries and diarrhea has been confirmed. However, the roles of bicarbonate have been suggested to affect not only intestinal pH environment but also intracellular pH and CPT-11/SN-38 dynamics. The present study proposed to clarify the hypothesis in CPT-11/SN-38-exposed colon cell line in various pH conditions adjusted by bicarbonate. HT29 cell pre-exposed to ~1.0 μM SN-38 lactone or carboxylate forms was incubated at different pH adjusted by either bicarbonate or HCl/NaOH. The degrees of SN-38-induced cell injury depended on the higher proportion of the toxic form (lactone) of SN-38 rather than mere pH condition of medium. Apoptosis and cell injury induced by SN-38 were significantly inhibited by bicarbonate in a dose-dependent manner. Intercellular pH acidification induced by SN-38 was significantly prevented by 30 mM bicarbonate. Cell cytotoxicity of SN-38 depended on not only extracellular but also intracellular pH that converts the SN-38 form, while the intracellular acidification was prevented by bicarbonate. The multiple regulations of bicarbonate on both exracellular and intracellular pH would be essential mechanism against intestinal cell injury by CPT-11/SN-38.展开更多
Susceptibilities to stress corrosion cracking (SCC) of X80 pipeline steel in high pH solutions with various concentrations of HCO3- at a passive potential of -0.2 V vs. SCE were investigated by slow strain rate tensil...Susceptibilities to stress corrosion cracking (SCC) of X80 pipeline steel in high pH solutions with various concentrations of HCO3- 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 HCO3- were discussed with the aid of electrochemical techniques. It is indicated that X80 steel shows enhanced 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.展开更多
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 t...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.展开更多
Fine spherical particle sized ceria （CeO2） was prepared by homogeneous precipitation method with ammonium bicarbonate as precipitant. The prepared CeO2 has the primary particle size of 10～50 nm when calcined betwee...Fine spherical particle sized ceria （CeO2） was prepared by homogeneous precipitation method with ammonium bicarbonate as precipitant. The prepared CeO2 has the primary particle size of 10～50 nm when calcined between 400～700 ℃ analyzed by XRD and the aggregated particle size is about 300 nm measured by LASER particle sizer. SEM, TG-DTA and Zeta-potential analyzer were employed individually to study the morphology and the formation of CeO2 product. It was found that excess NH4NO3 can serve as an sphericallization agent to prepare spherical CeO2 powder by precipitation method.展开更多
基金the Support Plan Projects of Science and Technology Department of Guizhou Province [No.(2021)YB453]。
文摘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.
基金financially supported by the Natural Science Foundation of Shandong Province (ZR2020QB132,ZR2020MB025)the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure (SKL202108SIC)the Taishan Scholar Program of Shandong Province (ts201712046)。
文摘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.
文摘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.
基金foundations of the National Natural Science Foundation of China [No. U1612441-2]Support Plan Projects of Science and Technology Department of Guizhou Province [No.(2021)YB453]。
文摘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.
基金funded by the National Key Basic Research Program of China under Grant No. 2013CB956701the National Natural Science Foundation of China under Grant No. 31070365Funded by talents introduction of Anqing Normal University (No. 14000100032)
文摘The effect of zinc(Zn) deficiency and excessive bicarbonate on the allocation and exudation of organic acids in plant organs(root, stem, and leaf) and root exudates of two Moraceae plants(Broussonetia papyrifera and Morus alba) were investigated. Two Moraceae plants were hydroponically grown and cultured in nutrient solution in four different treatments with 0.02 mM Zn or no Zn,combined with no or 10 mM bicarbonate. The variations of organic acids in different plant organs were similar to those of root exudates in the four treatments except B. papyrifera, which was in a treatment that was a combination of 0.02 mM Zn and no bicarbonate. The response characteristics in the production, translocation, and allocation of organic acids in the plant organs and root exudates varied with species and treatments. Organic acids in plant organs and root exudates increased under Zn-deficient conditions,excessive bicarbonate, or both. An increase of organic acids in the leaves resulted in an increase of root-exuded organic acids. B. papyrifera translocated more oxalate and citrate from the roots to the rhizosphere than M. alba under the dual influence of 10 mM bicarbonate and Zn deficiency. Organic acids of leaves may be derived from dark respiration and photorespiration. By comparison, organic acids in stems, roots, and root exudates may be derived from dark respiration and organic acid translocation from the leaves. These results provide evidence for the selective adaptation of plants to environments with low Zn levels or high bicarbonate levels such as a karst ecosystem.
文摘Diabetic ketoacidosis(DKA) is a severe and toocommon complication of uncontrolled diabetes mellitus. Acidosis is one of the fundamental disruptions stemming from the disease process, the complications of which are potentially lethal. Hydration and insulin administration have been the cornerstones of DKA therapy; however, adjunctive treatments such as the use of sodium bicarbonate and protocols that include serial monitoring with blood gas analysis have been much more controversial. There is substantial literature available regarding the use of exogenous sodium bicarbonate in mild to moderately severe acidosis; the bulk of the data argue against significant benefit in important clinical outcomes and suggest possible adverse effects with the use of bicarbonate. However, there is scant data to support or refute the role of bicarbonate therapy in very severe acidosis. Arterial blood gas(ABG) assessment is an element of some treatment protocols, including society guidelines, for DKA. We review the evidence supporting these recommendations. In addition, we review the data supporting some less cumbersome tests, including venous blood gas assessment and routine chemistries. It remains unclear that measurement of blood gas pH, via arterial or venous sampling, impacts management of the patient substantially enough to warrant the testing, especially if sodium bicarbonate administration is not being considered. There are special circumstances when serial ABG monitoring and/or sodium bicarbonate infusion are necessary, which we also review. Additional studies are needed to determine the utility of these interventions in patients with severe DKA and pH less than 7.0.
基金the foundations of the National Natural Science Foundation of China[No.U1612441-2]the National Key Research and Development Program of China[2016YFC0502602]Support Plan Projects of Science and Technology Department of Guizhou Province[No.(2021)YB453]。
文摘Photosynthesis is crucial to the reduction of carbon dioxide in the atmosphere.The key enzyme of photosynthesis,Ribulose-1,5-bisphosphate carboxylase/oxygenase(Rubisco),has two mutably competing substrates,CO2 and O2.It has features of carboxylase and oxygenase.Rubisco performs the function of carboxylase to reduce inorganic carbon to form organic substances,which precondition is that more carbon dioxide accumulates around it.Carbon dioxide concentrating mechanisms(CCMs)are vital to cope with the limit of carbon dioxide.Various bicarbonate use pathway has a differential contribution to inorganic carbon assimilation.Bicarbonate transport,extracellular bicarbonate dehydration,or H+-ATPase-driven bicarbonate uptake,which induced CCMs,can support a considerable share of photosynthesis in photosynthetic organisms.However,CCMs in thylakoid membranes may be the most important.The CCMs occurred in the plasma membrane were secondary,evolutionary,and inducible,while CCMs coupled with photosynthetic oxygen evolution in thylakoid membranes,were primitive,major,and indispensable.A hypothetical schematic model of CCMs occurred in the plasma membrane and thylakoid membranes being proposed.
文摘AIM: To explore whether serum bicarbonate at admission to intensive care unit(ICU) predicted development of acute kidney injury(AKI).METHODS:We studied all patients admitted to our ICU over a 2 year period(February 2010 to 2012).The ICU has a case mix of medical and surgical patients excluding cardiac surgical,trauma and neurosurgical patients.We analysed 2035 consecutive patients admitted to ICU during the study period.Data were collected by two investigators independently and in duplicate using a standardised spread sheet to ensure accuracy.Ambiguous data were checked for accuracy where indicated.AKI was defined using the Kidney Disease Improving Global Outcomes criteria.Patients were divided into two groups;patients who developed AKI or those who did not,in order to compare the baseline characteristics,and laboratory and physiologic data of the two cohorts.Regression analysis was used to identify if serum bicarbonate on admission predicted the development of AKI.RESULTS:Of 2036 patients 152(7.5%)were excluded due to missing data.AKI developed in 43.1%of the patients.The AKI group,compared to the nonAKI group,was sicker based on their lower systolic,diastolic and mean arterial pressures and a higher acutephysiology and chronic health evaluation(APACHE)Ⅲand SAPSⅡscores.Moreover,patients who developed AKI had more co-morbidities and a higher proportion of patients who developed AKI required mechanical ventilation.The multi-regression analysis of independent variables showed that serum bicarbonate on admission(OR=0.821;95%CI:0.796-0.846;P<0.0001),APACHEⅢ(OR=1.011;95%CI:1.007-1.015;P<0.0001),age(OR=1.016;95%CI:1.008-1.024;P<0.0001)and presence of sepsis at ICU admission(OR=2.819;95%CI:2.122-23.744;P=0.004)were each significant independent predictors of AKI.The area under the ROC curve was 0.8(95%CI:0.78-0.83),thereby demonstrating that the predictive model has relatively good discriminating power for predicting AKI.CONCLUSION:Serum bicarbonate on admission may independently be used to make a diagnosis of AKI.
基金the foundations of the National Key Research and Development Program of China [2016YFC0502602]the National Natural Science Foundation of China [No.U1612441-2]Support Plan Projects of Science and Technology Department of Guizhou Province [No.(2021)YB453]。
文摘If the photosynthetic organisms assimilated only CO_(2) in the Archean atmosphere,hydroxide ion in the Archean seawater would not increase.If plants would not consume bicarbonate as a direct substrate during photosynthesis,it is difficult to explain the evolution of Earth's environment.To date,it is generally accepted that photosynthetic O_(2) evolution of plants come from water photolysis.However,it should be debated by evaluating the effect of bicarbonate in photosynthetic O_(2) evolution,analyzing the role of carbonic anhydrase(CA) in photosynthetic O_(2) evolution,and the relationship between thylakoid CA and photosynthetic O_(2) evolution.In the paper,I propose that bicarbonate is directly used as substrate to participate in photosynthetic O_(2) evolution.The rationality of bicarbonate photolysis of plants is discussed from the thermodynamics and evolution of Earth's environment.The isotopic evidence that bicarbonate is not the direct substrate of photosynthetic O_(2) release is reexamined,and the new explanation of bicarbonate photolysis in photosynthetic O_(2) evolution is proposed.
文摘Because the use of phosphates has being recently diminished in meat industry due to the nutritional drawbacks of phosphates, some researchers started to evaluate sodium bicarbonate as phosphate replacer in meat products. The aim of this study was to evaluate the effect of different temperature combinations of dry air-cooking treatments (Air and Core temperatures: 160 - 76, 160 - 80, 200 - 76 and 200℃ - 80℃, respectively) on chemical composition, texture properties, water activity, freezable water and bound water, color, pH, and water binding capacity of phosphate and bicarbonate-marinated chicken breast. A batch of 24 h post-mortem broiler breast meat of 80 fillets was divided into two groups of marination treatments (0.3% sodium bicarbonate n = 40, 0.3% sodium tripolyphosphate n = 40) and was vacuum tumbled (45 min, ?0.95 mbar, 20 rpm). Different temperature-combinations cooking treatments significantly modified the chemical composition. Bicarbonate marinated fillets showed higher ability to retain water (67.3% vs. 65.7%, P 0.05) during severe heat treatment and lower cook losses (30.7% vs. 33.4%, P 0.05) when compared with phosphate-marinated fillets. The effect of changing the cooking temperatures on Texture Profile Analysis (hardness, cohesiveness, gumminess, springiness, and chewiness) was more tangible in phosphate marinated fillets than bicarbonate. Bicarbonate-marinated fillets showed significant differences in the percentage of bound water, latent heat, and water activity after cooking in comparison to phosphate-marinated fillets. The results of this study revealed that phosphate-marinated fillets interacted with heat treatments in different patterns in comparison with bicarbonate-marinated fillets.
文摘Objectives: Recent reports on venous blood gas analysis have shown that venous bicarbonate concentration is useful in the evaluation of the body acid-base status. Most of these reports have been based on the Bland-Altman analysis comparing arterial and venous blood gas values. We intended to elucidate any factors that decrease the agreement between venous and arterial bicarbonate concentrations, which might impair the usefulness of venous blood gas analysis. Methods: Healthy volunteers and patients with various diseases (n = 141) were evaluated by simultaneous arterial and venous blood sampling and Bland-Altman analysis. The venous-arterial bicarbonate concentration difference was compared between healthy volunteers and untreated respiratory alkalosis patients. Intentional hyperventilation (30 or 60 breaths/min, for 3 min) was also performed on 6 healthy volunteers and the venous-arterial bicarbonate concentration difference was evaluated. Results: The relative average bias in bicarbonate concentration was 2.00 mEq/l with venous bicarbonate higher than arterial bicarbonate with 95% limits of agreement of ±4.15 mEq/l. Hyperventilation challenges increased the venous-arterial bicarbonate concentration difference in an intensity-dependent manner. The venous-arterial bicarbonate concentration difference was higher in untreated respiratory alkalosis patients than in healthy volunteers (P Conclusion: Although venous bicarbonate may be useful to evaluate the body acid-base status, hyperventilation increases the venous-arterial bicarbonate concentration difference. Physicians should keep this phenomenon in mind.
基金This work was supported by a grant from the Faculty of Medicine,Khon Kaen University,Thailand.
文摘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.
文摘This report aims to look at the role of Sodium bicarbonate as a potent Ergogenic aid and its role in improving the performance of athletes. It includes the mechanism of action of sodium bicarbonate during high-intensity exercise. The report also shows the various types of athletes who can be benefited from sodium bicarbonate loading, evidences for improvement in performance, conflicting evidences, recommended dosages and side-effects for bicarbonate loading.
文摘In this study, we investigated the effect of sodium bicarbonate (NaHCO3) supplementation at a dose of 0.2 g·kg−1 40 min before an exercise on intermittent endurance performance and gastrointestinal distress. The participants were six healthy male students of a university. The Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2) was used for the evaluation of intermittent endurance. The participants ingested water (Cont) or NaHCO3 independently at three timings. After drinking water, the Yo-Yo IR1 was performed for 2 min as warm-up. After resting for 5 min, the Yo-Yo IR2 was initiated. The measurement items were exercise distance, nutrition intake, biochemical test results, and blood gas analysis findings. The participants who ingested NaHCO3 had a 14% extended distance than those who ingested Cont, and 2/3 of those who took NaHCO3 showed a better motor performance. No significant difference was observed between the participants who took Cont and NaHCO3 in terms of pH level at baseline, and the NaHCO3 level was significantly higher during pre- and post-exercise (p 3 in terms of bicarbonate ion level at baseline, and the NaHCO3 level was significantly higher during pre- and post-exercise (p 3 at a low dose (0.2 g·kg−1), their exercise ability during an intermittent endurance test has improved. Furthermore, when digestive absorption is considered, eating a meal in advance may be able to suppress the onset of gastrointestinal distress.
文摘Background and aims: we aimed to detect the outcome values of adding fentanyl, dexamethasone and sodium bicarbonate to mixture of local anesthetic in peribulbar block for vitreoretinal surgery. Methods: 120 adult ASA I & II patients, admitted for vitreoretinal surgery under peribulbar block were included in this comparative study. This study included 4 groups: Group I: (30) patients using a mixture of 1 ml normal saline, 4 ml lidocaine 2% plus 4 ml from bupivacaine 0.5% 20 ml vial containing hyaluronidase 1500 IU. Group II: (30) patients using a mixture of 1 ml of sodium bicarbonate (from 1 ml sodium bicarbonate 8.4% diluted in 10 ml normal saline), 4 ml lidocaine 2% plus 4 ml from bupivacaine 0.5% 20 ml vial containing hyaluronidase 1500 IU. Group III: (30) patients using a mixture of 1 ml fentanyl 20 μg (from a mixture of fentanyl 100 μg diluted in 5 ml normal saline), 4 ml lidocaine 2% plus 4 ml from bupivacaine 0.5% 20 ml vial containing hyaluronidase 1500 IU. Group IV: (30) patients using a mixture of 1 ml of 4 mg dexamethasone (1 ampoule = 8 mg/2 ml), 4 ml lidocaine 2% plus 4 ml from bupivacaine 0.5% 20 ml vial containing hyaluronidase 1500 IU. We measured the onset and duration of anesthesia, IOP, eyelid and global akinesia, postoperative pain by numerical pain rating scale, first analgesic requirement and postoperative side effects. Results: No significant differences were detected among the four groups as respect to age, sex and the intraocular pressure (IOP) before the anesthesia block. While the intraocular pressure (IOP) after the anesthesia block there was a significant difference, as IOP was markedly decreased postoperatively in group II compared with other groups. As regard to the onset & duration of anesthesia there was significant difference among all groups, there was rapid onset and prolonged duration of anesthesia in group III compared with other groups (1.77 ± 0.63 & 5.03 ± 0.89) respectively. As regard the onset of lid akinesia there was significant difference among the four groups with better outcome in group III, as in group III represented the most rapid onset of lid akinesia. As respecting to the onset of global akinesia there was significant difference among the four groups. There was better outcome in group III as it represented more rapid onset of global akinesia compared with other groups. There were significant differences among the four groups as regard postoperative pain all over 6 hours, better results were in group III (0.27 ± 0.69) compared with group I (2.23 ± 1.17), group II (2.00 ± 1.70), group IV (0.67 ± 0.71). As regarding to the first time for analgesic requirement there were significant differences among groups, there was no request for analgesia with better outcome in group III with increasing need to the analgesic medication in group I compared to group II and group IV. As regard side effects postoperatively there were few side effects in all groups with few numbers of cases in groups III only one patient. Although these differences in number of patients are not significant among the four groups. Conclusion: Addition of sodium bicarbonate to local anesthetic mixture was the best way in lowering the IOP other than other groups and addition of fentanyl to local anesthesia provided more rapid onset and duration of anesthesia, more rapid onset and duration for lid and global akinesia, less pain, less analgesic requirement and minimal side effects than the other groups.
文摘AIM To examine possible alterations in acid-base parameters in patients switching from lanthanum carbonate(LanC) to sucroferric oxyhydroxide(SFOH). METHODS Fifteen stable hemodialysis patients were switched from LanC to SFOH. Only nine continued on SFOH, three returned to LanC and the other three switched to sevelamer carbonate. The later six patients served as a control group to the SFOH group of nine patients. Blood was sampled on the 3-d and the last 2-d interval of the week prior to switching and six weeks after. Bicarbonate levels(HCO_3^-), pH, pO_2, pCO_2 were measured, and the mean of the two measurements(3-d and 2-d interval) was calculated. RESULTS Comparing pre-switching to post-switching measurementsin the SFOH group, no statistically significant differences were found in any of the parameters studied. The mean pre-switching HCO_3^-was 22.41 ± 1.66 mmol/L and the mean post-switching was 22.62 ± 2.25 mmol/L(P = 0.889). Respectively, the mean pH= 7.38 ± 0.03 vs 7.39 ± 0.03(P = 0.635), mean pCO_2= 38.41 ± 3.29 vs 38.37 ± 3.62 mmHg(P = 0.767), and Phosphate = 1.57 ± 0.27 vs 1.36 ± 0.38 mmol/L(P = 0.214). There were not any significant differences when we performed the same analyses in the control group or between the SFOH group and control group. No correlations were found, either between pre-switching LanC daily dose or between postswitching daily dose of the new binder and the measured parameters.CONCLUSION In our small study, switching from LanC to SFOH did not have any significant effect on blood bicarbonate levels and gas analysis, indicating that there is no need to change hemodialysis prescription regarding these parameters.
文摘The anti-cancer therapy of irinotecan (CPT-11) is often limited due to severe late-onset diarrhea. Because the higher toxic form of CPT-11/its active metabolite (SN-38) is produced at acidification, the usefulness of oral sodium bicarbonate treatment against the CPT-11/SN-38-induced intestinal injuries and diarrhea has been confirmed. However, the roles of bicarbonate have been suggested to affect not only intestinal pH environment but also intracellular pH and CPT-11/SN-38 dynamics. The present study proposed to clarify the hypothesis in CPT-11/SN-38-exposed colon cell line in various pH conditions adjusted by bicarbonate. HT29 cell pre-exposed to ~1.0 μM SN-38 lactone or carboxylate forms was incubated at different pH adjusted by either bicarbonate or HCl/NaOH. The degrees of SN-38-induced cell injury depended on the higher proportion of the toxic form (lactone) of SN-38 rather than mere pH condition of medium. Apoptosis and cell injury induced by SN-38 were significantly inhibited by bicarbonate in a dose-dependent manner. Intercellular pH acidification induced by SN-38 was significantly prevented by 30 mM bicarbonate. Cell cytotoxicity of SN-38 depended on not only extracellular but also intracellular pH that converts the SN-38 form, while the intracellular acidification was prevented by bicarbonate. The multiple regulations of bicarbonate on both exracellular and intracellular pH would be essential mechanism against intestinal cell injury by CPT-11/SN-38.
文摘Susceptibilities to stress corrosion cracking (SCC) of X80 pipeline steel in high pH solutions with various concentrations of HCO3- 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 HCO3- were discussed with the aid of electrochemical techniques. It is indicated that X80 steel shows enhanced 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.
基金supported by the National Science and Technology Infrastructure Platforms Construction Projects (No.2005DKA10400)
文摘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.
基金Project supported by Rare Earth Department of National Development Committee Preparation of High Quality Polishing Powder
文摘Fine spherical particle sized ceria （CeO2） was prepared by homogeneous precipitation method with ammonium bicarbonate as precipitant. The prepared CeO2 has the primary particle size of 10～50 nm when calcined between 400～700 ℃ analyzed by XRD and the aggregated particle size is about 300 nm measured by LASER particle sizer. SEM, TG-DTA and Zeta-potential analyzer were employed individually to study the morphology and the formation of CeO2 product. It was found that excess NH4NO3 can serve as an sphericallization agent to prepare spherical CeO2 powder by precipitation method.
