Ratio Of HCO3 Research Articles

Identification of seawater intrusion in Gapura Sub-district, Sumenep Regency, East Java, Indonesia

Gapura sub-district is located in the Sumenep Regency, Madura Island, that also recognized as the center of salt production. Due to not availability of a clean water network from the municipal water network (PDAM), the daily water need of the community is provided by groundwater. Local people have reported several brackish waters in the wells since a few years ago. Therefore, the purpose of this research is to identify seawater intrusion potential in this area. The seawater intrusion is analyzed based on the value of electrical conductivity (EC) and groundwater hydrochemistry. From the analysis of EC values, it can be concluded that there are two out of thirty groundwater samples classified as moderately saline water, while in the study of groundwater ion values, both two samples have chloride values that are more than 240 mg/L. However, the Cl and HCO3 ratio show that the two samples will only have a small effect on seawater. Therefore, it can be concluded that the Gapura sub-district does not have seawater intrusion. High salinity in some wells is mostly coming from salt production in this area.

Effect of arterial blood bicarbonate (HCO3\u2212) concentration on the accuracy of STOP-Bang questionnaire screening for obstructive sleep apnea

BackgroundTo evaluate the effect of arterial bicarbonate (HCO3−) concentration on the accuracy of STOP-Bang questionnaire (SBQ) screening for obstructive sleep apnea (OSA).MethodsA total of 144 patients with suspected OSA were included. Polysomnograms (PSG) and blood gas analysis were performed, and the Epworth Sleepiness Scale (ESS), STOP-Bang questionnaire, and Berlin questionnaire were completed. The correlation between the arterial HCO3− concentration, apnea hypopnea index (AHI), and other related indicators was analyzed. The scoring results of the ESS, SBQ, and Berlin questionnaire were compared with the PSG results, and the sensitivity and specificity were calculated in the form of a four-cell table. The changes in the sensitivity and specificity of OSA screening after SBQ alone and combined with HCO3− concentration were compared, and ROC curves were drawn.ResultsArterial HCO3− concentration was positively correlated with AHI (r = 0.537, P < 0.001). The ratio of HCO3− concentration ≥ 24.6 mmol/L in the non-OSA group was significantly lower than that in the OSA group (25.0% VS 80.8%, P < 0.001). The sensitivity of the SBQ was higher than that of the ESS (97.5% VS 81.7%, P < 0.001) and the Berlin questionnaire (97.5% VS 79.2%, P < 0.001). There was no statistical significance in the specificity of the three scales (25%, 37.5%, 37.5%). A combined SBQ score ≥ 3 and HCO3− concentration ≥ 24.6 mmol/L showed increased specificity and decreased sensitivity compared with an SBQ score ≥ 3 alone, with a corresponding AUC of 0.771 (P < 0.01) and 0.613 (P > 0.05), respectively.ConclusionThe sensitivity of the SBQ was better than that of the Berlin questionnaire and ESS. After combining arterial blood HCO3− concentration, the SBQ questionnaire increased the specificity of OSA prediction and decreased the sensitivity, which improved the accuracy of screening.

A NEW APPROACH TO MEDICAL DIAGNOSIS OF COVID-19 AND CONTROLLING THE EFFECTS OF COVID-19 ON ARTERIAL BLOOD GAS WORKING

Aim: The purpose of this study is to provide information about the effect of the defense mechanism formed by the lung mucosal surface against Covid-19 and the effect of Covid-19's lung involvement on Arterial Blood Gas Values, whose number of cases and mortality rate increases day by day in our country. In addition, by sharing a new method in the diagnosis of Covid-19, important issues in the monitoring of Covid-19 patients with a high symptom burden and high risk of complications associated with lung damage were highlighted. Method: The blood values of 4000 patients who read the consent form and gave consent were collected in the SPSS 26 program in our study conducted in various public hospitals within the city of Istanbul with the permission of Istanbul Provincial Health Directorate with the number 15916306-604.02 and dated 08.09.2020. With our quantitative research, it is possible to interpret the arterial blood gas values of patients who have been diagnosed with covid-19 positive, to determine the common output and to determine the treatment methods, drugs, etc. It is aimed to be a resource for the studies. Common values were searched in the formed control groups and analyzed in accordance with the Henderson-Hasselbalch equation and in accordance with the literature. Arterial and vein blood from the patients participating in the study were collected in anaerobic environment with sterile syringes containing 1.0 or 5.0 mL lyophilized heparin. During blood collection, necessary measures have been taken to prevent or minimize blood contact with air. Since arterial blood gas collection requires expertise, no results that could be interpreted as suspicious were included in the study. Analyzes were performed with pH, pO2, pCO2, HCO3, LDH and Hgb values of 4000 participants. Results: Our study includes 4000 people between the ages of 19-88, who have been diagnosed with Covid-19 and voluntarily agree to participate in our study. 58% of the patients who participated in the study by approving the consent form were male and 42% were female. In order for the blood values of the deceased patients to be used in our study, permission was also requested from their relatives. In this group, 68% of the participants are male and 32% are female participants. It was found that the pO2 and pCO2 ratio of 4000 patients participating in the study did not exceed 10% of the LDH and HCO3 ratio (1O X (LDH) / 100 X (HCO3)&gt; pO2 / pCO2). If the equation is correct in the equation [(LDH) X (pCO2)] / [(HCO3) X (pO2)] ≤ (Hgb), the covid-19 diagnostic status is positive. Conclusion: : It has been determined that the pO2 / pCO2 ratio does not exceed 10% of the LDH / HCO3 ratio in the critical cases examined within the scope of the research. As this rate decreased, the rate of survival of patients also decreased. Therefore, in positive cases, a reference equation that can detect covid-19 positivity has been found by looking at whether there is an anion gap and metabolic acidosis is observed and LDH level. This formula; [(LDH) X (pCO2)] / [(HCO3) X (pO2)] ≤ (Hgb). When the formula was applied, it was determined that the ratio of [(LDH) X (pCO2)] / [(HCO3) X (pO2)] was equal or less than the value of hemoglobin (Hgb).

Fe and C isotopes constrain the pathways of hematite and Fe–rich carbonates formation in the Late Neoproterozoic Dahongliutan BIF, NW China

Unlike most Neoproterozoic BIFs in which Fe occurs almost exclusively in hematite, the Late Neoproterozoic Dahongliutan BIF uniquely contains Fe oxides (hematite), Fe–rich carbonates (siderite and ankerite) and Ca–Mg carbonates (calcite and dolomite). The diversification of minerals presents a unique opportunity to constrain the biotic and/or abiotic pathways for the precipitation of Fe–bearing minerals involved in Neoproterozoic BIF genesis. Here, we present integrated Fe, Nd and C compositions of hematite, Fe–rich carbonates, bulk–rock various facies BIFs, silicified calcic marbles and schists from the Dahongliutan BIF. These data suggest that the aqueous Fe2+ with light δ56Fe (~−1.60‰) at Dahongliutan was sourced from mixed continentally derived Fe (δ56Fe ~ −2‰) that was mobilized by microbial dissimilatory Fe reduction (DIR) and hydrothermally sourced Fe (δ56Fe ~ 0‰) from MORB systems. Lower than 65% of this dual–source mixed Fe occurred oxidation and formation of Fe(OH)3 via limited atmospheric O2, and/or anaerobic photosynthetic Fe2+ oxidation. The majority of these poorly crystalline Fe(OH)3 precipitates undergo dehydration and recrystallization to eventually bury as hematite with light δ56Fe (averaging −0.15‰). δ56Fe (~−0.11‰) and δ13CV-PDB (−4.00‰ to −6.60‰) of the siderite suggest that conversion of a small amount of Fe(OH)3 into siderite occurred via near–complete reduction by DIR. This DIR process is coupled to the oxidation of organic C, in which the ratio of HCO3− derived from oxidation of CH2O (HCO3−org) to total HCO3− (HCO3−total) = 1/4. Petrographic evidence (the common occurrence of hematite inclusions in the siderite and ankerite), coupled with mineral chemistry, support a model that some siderite transforminto ankerite with consistent δ56Fe (~−0.11‰) and δ13CV-PDB values (−4.20‰ to −5.40‰). In summary, our results demonstrate that DIR play an important role in Neoproterozoic BIFs.

Integrated seawater intrusion study of coastal region of Thiruvallur district, Tamil Nadu, South India

The groundwater is the main resource of water for irrigation activity in river lacking area. The freshwater–seawater interface in the study region that has existed 3 km away from the coast in the year 1969 has been found to be migrated to distance of 13 km from the coast during the year 2007 noticed by the Central Ground Water Board (Central ground water board’s district groundwater brochure, Thiruvallur district, Tamil Nadu, 2007). Integrated geochemical and geophysical techniques were carried out in the study area to decode subsurface geologic pattern and delineate the seawater–freshwater zones. Total numbers of 50 samples were collected from the entire study area and analyzed for major ions. The considerable samples are brackish scenery of groundwater water at low depth. Chadha and Piper’s plots categorize the coastal groundwater into Na–HCO3, Ca–Na–HCO3, Ca–HCO3, and Na–Cl water facies, with Ca–HCO3 as the dominant. Cl/CO3 + HCO3 ratio, Cl/HCO3, and ionic strength, Mg/Ca and Cl/HCO3 ratios show that most of the samples in the study area are affected by seawater intrusion, which is also confirmed by the geophysical method. The results of vertical electrical sounding carried out in the study area reveal the low transverse resistance and high longitudinal conductance. It suggests the brackish nature of the groundwater in the eastern part of the study area may be due to the seawater intrusion. The final map using GIS platforms productively delineates the location that is really undergoing seawater and freshwater zone is migrated toward the inland. The article suggested further studies to arrest the migration of sea/freshwater interface into the land and avoid overexploitation of groundwater to further development.

Assessment of Hydrochemistry and Unconfined Groundwater Quality At East Simeulue Coastal Area, Aceh Province

East Simulue Subdistrict is one of the areas that has coastal tourism potential that is very good to develop. Tourism development cannot be separated from the provide of tourism facilities and infrastructure, one of which is public infrastructure in the form of providing clean water. Determination of hydrogeochemical characteristics and determination of groundwater quality index (Water Quality Index) is one method of assessing groundwater worthiness in East Simulue. Ground water in the Simulue East coastal area is dominated by HCO3 elements, with a value of Cl / HCO3 ratio &lt;0.5 which indicates that ground water is not affected by sea water, while the Na / Cl ratio&gt; 1 indicates that groundwater has a process of groundwater hydrolysis. There are 6 types of facies hydrochemical facies of East Simulue groundwater, Mg-HCO3, Ca-HCO3, mixing Ca-Na-HCO3, Na-HCO3, Na-SO4 and Ca-SO4, but overall dominated by Mg-HCO3 facies. The ratio of Na ++ K +/ (Na ++ K ++ Ca2 +) as a function of TDS also shows that the chemistry of East Simeulue groundwater is dominated by the interaction of rock (formation) with groundwater. Groundwater quality index classification in Simuelue coastal shows that overall groundwater is in the category of excellent water (good) and good water (good) category.

Isotopic Composition and Origin of Sulfide and Sulfate Species of Sulfur in Thermal Waters of Jiangxi Province (China)

The reduced sulfur species, sulfide, elemental and thiosulfate were considered in the thermal waters of Jiangxi Province for the first time. It is shown that the sulfur speciation content significantly varies and depends on the pH values. The major part of reduced sulfur refers to sulfide species in the nitric thermal waters, to elemental—in the carbon dioxide thermal waters. The presence of both reduced and oxidized sulfur speciation indicates the possibility of sulfide minerals hydrolysis and disproportionation of the product of this reaction (SO2) with the participation of hot water with the formation of elemental and sulfate sulfur. The isotopic composition of dissolved sulfate and sulfide sulfur speciation has shown that the process of bacterial reduction proceeds in the thermal waters, accompanied by accumulation of relatively heavy sulfur isotope in sulfates. Simultaneously with reduction, the oxidation of both sulfide minerals and newly formed hydrosulfide proceeds with formation of elemental, thiosulfates and also sulfates in the discharge zone was proceeded. It is shown that the process of sulfide oxidation mostly occurs in carbon dioxide thermal waters. Therefore, the elemental sulfur is predominant in carbon dioxide waters. The oxidation process is less significant in the nitric thermal waters, whereby the concentrations of sulfide ion are higher than sulfates. The ambiguous effect of sulfate reduction on the hydrogeochemical environment of the thermal waters is confirmed by the differing value of the carbon isotope ratio of HCO3− in the considered waters. The obtained isotopic composition data 34δS(SO42−) indicate host rocks as a source of sulfates in the thermal waters of Jiangxi Province.

Seawater intrusion vulnerability in the coastal aquifers of southern India-an appraisal of the GALDIT model, parameters' sensitivity, and hydrochemical indicators.

An appraisal of seawater intrusion into the coastal aquifers is one of the major issues for groundwater resource management. The GALDIT model applies to the analysis of multiple parameters using systematic GIS techniques for mapping and assessment of seawater intrusion vulnerability. It demarcates the mapping of potential vulnerability that shows a higher vulnerability to seawater intrusion in various parts of the coast and the estimated vulnerability index value of 7.50 and 9.64. An area of 33.0km2 spread in the low-lying coastal area comprising estuaries, salt marshes, and saltpans shows the high vulnerability condition with an estimated vulnerability value of 6.42-7.50. An area of 73.20km2 spread over coastal and alluvial plains experiences moderate vulnerability (temporal salinity in the groundwater sources) with an estimated vulnerability index value of 5.46-6.42. Aquifers underlying coastal uplands (hard rock formations) and some parts of accretionary beaches (2.05km2) are relatively protected fresh groundwater sources, wherein the estimated vulnerability index is 4.55-5.46. The vulnerability mapping of the GALDIT model using hydrochemical analysis of primary groundwater parameters such as TDS, Cl-, HCO3, and Cl-/HCO3 ratio is validated. Higher concentration of TDS (2637-4162mg/l) and Cl- (1268-2347mg/l) is taken for the areas falling under higher vulnerability to seawater intrusion, especially in the placer mining sites and coastal areas facing erosion. Similarly, the groundwater sources of the low-lying areas including estuaries, salt marshes, saltpans, and backwater were noted to have higher values of Cl-/HCO3 with a rationality of 9.87-12.18. Hydrological facies shows the highest concentration of NaCl in the groundwater sources within the proximity of eroded beaches, saltwater bodies, and sand mining areas. A hydrochemical facies evolution (HFE) diagram represents the hydrochemical facies of groundwater elements that shows an intrusion of seawater into the coastal aquifers underlying the very high vulnerable zones. Higher bicarbonate concentration (233-318mg/l) is noticed in the upland areas and some parts of dunes and accreted beaches, sandy coasts, and uplands. Vulnerability analysis reveals that those areas near saltwater bodies and eroding coasts are prone to lateral and vertical diffusion of saltwater. The geodatabase developed through such modeling studies can help in planning and developing activities for sustainable groundwater resource management in coastal areas.

High-rate partial nitritation using porous poly(vinyl alcohol) sponge

Poly(vinyl alcohol) (PVA) has been utilized as a support material for the immobilization of nitrifying bacteria without the comprehensive survey of partial nitritation. In the present study, the activities of nitrifiers and the maximum nitrogen conversion rate of partial nitritation with PVA sponge-cubes were specified according to different conditions. The selective enrichment of ammonia-oxidizing bacteria (AOB) on PVA sponge-cubes was achieved by the competition between AOB and nitrite-oxidizing bacteria for dissolved oxygen. The efficiency of ammonia oxidation was proportional to the concentration of HCO3 (-) with the molar ratio of HCO3 (-)-C/NH4 (+)-N = 1.91 and a half of the ratio was applied to the further experiments to ensure stable partial nitritation. The maximum nitrogen conversion rate of partial nitritation was dependent on the volume, not the size of sponge-cubes. The partial nitritation showed the superior rate performance of 3.09 kg N/m(3) day with the packing ratio of 32 % of 5 × 5 × 5 mm(3) PVA sponge-cubes.

Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy.

Many salinity gradient energy technologies such as reverse electrodialysis (RED) rely on highly selective anion transport through polymeric anion exchange membranes. While there is considerable interest in using thermolytic solutions such as ammonium bicarbonate (AmB) in RED processes for closed-loop conversion of heat energy to electricity, little is known about membrane performance in this electrolyte. The resistances of two commercially available cation exchange membranes in AmB were lower than their resistances in NaCl. However, the resistances of commercially available anion exchange membranes (AEMs) were much larger in AmB than in NaCl, which would adversely affect energy recovery. The properties of a series of quaternary ammonium-functionalized poly(phenylene oxide) and Radel-based AEMs were therefore examined to understand the reasons for increased resistance in AmB to overcome this performance penalty due to the lower mobility of bicarbonate, 4.59 × 10-4 cm2/(V s), compared to chloride, 7.90 × 10-4 cm2/(V s) (the dilute aqueous solution mobility ratio of HCO3- to Cl- is 0.58). Most membrane resistances were generally consistent with the dilute solution mobilities of the anions. For a few key samples, however, increased water uptake in AmB solution reduced the ionic resistance of the polymer compared to its resistance in NaCl solution. This increased water uptake was attributed to the greater hydration of the bicarbonate ion compared to the chloride ion. The increased resistance due to the use of bicarbonate as opposed to chloride ions in AEMs can therefore be mitigated by designing polymers that swell more in AmB compared to NaCl solutions, enabling more efficient energy recovery using AmB thermolytic solutions in RED.

Hydrogeochemical and isotopic study of the Kumho River, Korea: implications for anthropogenic and seasonal effects

The geochemical and isotopic compositions of river water are controlled by different factors. The seasonal and spatial variations in the geochemical composition, δD, δ18O, and δ15N–NO3 of the Kumho River were investigated to reveal the geochemical processes occurring at different seasons. The Kumho River, which runs through different geologic terrains with different land use characteristics, is the largest tributary of the Nakdong River, the longest river in South Korea. The data varied significantly according to the land use and the season. Each monitoring station showed the lowest concentrations of various ions during July, the rainy season, due to the increase of precipitation rate. The ionic concentrations gradually increased downstream by the mineral weathering and anthropogenic activity. At the upper regions of the river, Ca and HCO3, which are closely associated with mineral weathering, were the most dominant cation and anion, respectively. The relatively high Si concentration of the headwater samples, caused by the weathering of volcanic rocks, also showed the importance of weathering in the upper regions mainly composed of volcanic rocks. The downstream regions of the Kumho River are mainly influenced by sedimentary rocks. At the lower reaches of the river, especially near the industrial complexes in Daegu, the third largest city in Korea, Na, Cl, and SO4 became the dominant ions, indicating that the anthropogenic pollution became more important in regulating the chemical composition of the river. The increasing (Ca + Mg + Na + K)/HCO3 ratio downstream also indicates that the anthropogenic effects became more important as the river flows downstream. The isotopic compositions of δD and δ18O indicate that the river waters were significantly affected by evaporation during May and July, but the evaporation effect was relatively low during October. The isotopic composition of δ15N–NO3 increased downstream, also confirming that anthropogenic effects became more significant at the lower reach of the river and near Daegu.

A new delta current method for estimating the transport stoichiometry of electrogenic transporters

The stoichiometry of electrogenic transporters is an important determinant of their function. If an electrogenic transporter transports ions in a fixed stoichiometric ratio q, q can be determined by the reversal potential Erev with known intra‐ and extra‐cellular concentrations of transporting ions given that a specific blocker is available. An alternative approach widely used is to calculate delta Erev (ΔErev) by altering concentrations of a transported ion. This approach is based on the hypothesis that the effects of other channels and transporters in cell membrane on Erev are additive. However, the Goldman‐Hodgkin‐Katz (GHK) equation suggests otherwise: Erev is a logarithmic function of the sum of different conductances rather than being additive. In the present study, we propose a delta current (ΔI) method that does not require a blocker. ΔI instead of ΔErev is determined by altering the external concentration of a transported ion thereby eliminating other currents. The ratio of ΔI at two different membrane voltages (E1 and E2) is: ΔI2/ΔI1= (E2/E1) ((exp ((q−1) FE1/RT)−1)/(exp ((q−1) FE2/RT)−1)). ΔI2/ΔI1 only depends on q, E1, and E2. We tested this new ΔI methodology in patch‐clamp experiments of HEK‐293 cells expressing NBC1e1‐A or NBC4c. Our data show that the ΔI equation accurately calculates a stoichiometry ratio of HCO3− :Na+of 2 demonstrating the utility of this new methodology.

Photochemical and enzymatic methanol synthesis from HCO3− by dehydrogenases using water-soluble zinc porphyrin in aqueous media

We studied the photochemical and enzymatic synthesis of methanol from HCO3− using formate dehydrogenase (FDH) isolated from Candida boidinii, aldehyde dehydrogenase (AldDH) and alcohol dehydrogenase (ADH) isolated from yeast, and the photoreduction of methyl viologen (MV2+) by the visible-light sensitization using zinc tetraphenylporphyrin tetrasulfonate (ZnTPPS) in the presence of triethanolamine (TEOA). When a sample solution containing ZnTPPS, MV2+, FDH, AldDH, ADH, TEOA, and NaHCO3 in potassium phosphate buffer solution (pH 8) was irradiated, the amount of methanol produced increased with the irradiation time. After irradiation for 3h, 4.5μmoldm−3 of methanol was produced from 100μmoldm−3 NaHCO3. The conversion ratio of HCO3− to methanol was approximately 4.5%. This result indicates that a system for the photochemical synthesis of methanol from HCO3− can be developed by using three dehydrogenases (FDH, AldDH, and ADH) and for the photoreduction of MV2+ through the photosensitization of ZnTPPS in aqueous media.

Assessment of groundwater corrosiveness for unconfined aquifer system at Kalpakkam

Groundwater samples from the shallow unconfined aquifer were collected from fifteen borewells in Kalpakkam nuclear plant site and were analysed for various physico-chemical parameters. The pH, temperature, salinity, TDS and EC were measured in the field. The borewell samples were analysed in the laboratory for Ca(2+), Mg(2+), Na(+), Cl(-), CO(2-)(3), HC(O-)(3), N(O-)(3) and SO(2-)(4). The Piper Trilinear diagram showed that majority of the borewell samples fall in Na - Cl +SO(4) type and Na - CO(3)+HCO(3) type. The Cl: HCO3 ratio of some borewell samples are categorized under injuriously contaminated to highly injurious type. The higher salinity levels encountered in some borewells emphasized the need for better understanding of groundwater corrosiveness. Accordingly, the Langeliar saturation Index (SI), Aggressivity index (AI) and Larson ratio (LnR) were evaluated for assessing the corrosive nature of the groundwater. The saline water incursion in the southern part of the study area increased the ionic concentration of Cl(-) and [Formula: see text] that made the groundwater corrosive.

Photochemical and Enzymatic Synthesis of Malic Acid from Pyruvic Acid and HCO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; with Combination System of Zinc Chlorin-e&lt;sub&gt;6&lt;/sub&gt; and Malic Enzyme in Aqueous Medium

Photochemical and enzymatic synthesis of malic acid from pyruvic acid and HCO3- was studied with malic enzyme (ME) and NADP+ photoreduction with ferredoxin-NADP+-reductase (FNR) by visible light photo-sensitization of the chlorophyll derivative, zinc chlorin-e6 (ZnChl-e6), in the presence of NADH as an electron-donating reagent and methylviologen (MV2+) as an electron-relay reagent. NADPH was produced by irradiation of the reactant solution containing NADH, ZnChl-e6, MV2+, NADP+ and FNR in Bis-Tris buffer (pH 8.0). After 180-min irradiation, 8.3 mmol·dm-3 NADPH was produced under the optimum conditions with 10 mmol·dm-3 of NADP+. The reduction ratio of NADP+ to NADPH was about 83%. Malic acid was produced by irradiation with visible light (>390 nm) of the reactant solution containing NADH, ZnChl-e6, methylviologen (MV2+), pyruvic acid, NaHCO3, NADP+, ferredoxin-NADP+-reductase (FNR) and ME. Malic acid production was 2.0 mmol·dm-3 after 3-h irradiation under the optimum conditions with NADH, ZnChl-e6, MV2+, FNR, pyruvic acid, NaHCO3, NADP+ and ME. The ratio of HCO3- and pyruvic acid to malic acid was about 20% under the optimum conditions.

Electrophysiological characterization of native Na+–HCO3– cotransporter current in bovine parotid acinar cells

Using patch-clamp and molecular biological techniques, we identified and characterized membrane currents most likely generated by an electrogenic Na+-HCO3- cotransporter (NBCe) in acutely dissociated bovine parotid acinar (BPA) cells. When BPA cells were dialysed with a N-methyl-D-glucamine (NMDG)-glutamate-rich pipette solution, switching a Na-glutamate-rich, nominally HCO3--free bath solution to the one containing 25 mM HCO3-, but not Cl-, elicited a whole-cell current with a linear current-voltage relation. The HCO3- evoked current was abolished by total replacement of extracellular Na+ (Na+o) with NMDG or by 0.5 mM 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid (DIDS), and was only partially supported by Li+o, but not by K+o, Cs+o, and cholineo. The reversal potential shift of DIDS (0.5 mM)-sensitive current induced by a change of [Na+]o corresponded to an apparent coupling ratio of HCO3- to Na+ of 2. RT-PCR analysis showed the presence of transcripts of NBCe1-B, but not NBCe1-A in BPA cells. Electrophysiological and pharmacological properties of whole-cell currents recorded from HEK293 cells transfected with the NBCe1-B, which was cloned from BPA cells resembled those of the native currents. Non-invasive measurements of membrane potential changes in the cell-attached patch configuration indicated that an NBCe activity is present in intact unstimulated BPA cells bathed in a 25 mM HCO3--containing solution. Collectively, these results not only suggest that an NBCe is present, functional and may be mediated, at least in part, by NBCe1-B in BPA cells, but also provide the first electrophysiological characterization of transport properties of NBCe expressed in native exocrine glands.

Conversion electron Mössbauer spectroscopy and X-ray diffraction studies of the formation of carbonate-containing green rust one by corrosion of metallic iron in NaHCO 3 and (NaHCO 3 + NaCl) solutions

The corrosion of α-iron in 0.1 mol 1 −1 NaHCO 3 solutions, with or without additional NaCl, leads to the formation of a deep-green homogeneous layer which covers the metallic surface. It is analysed by X-ray diffraction (XRD) and conversion electron Mössbauer spectroscopy (CEMS) and proves to be made of carbonate-containing green rust one, GR1(CO 3 2−), an Fe (II)-Fe (III) hydroxide-carbonate with chemical formula [Fe 4 staggered(II)Fe 2 staggered(III)(OH) 12][CO 3·2H 2O]. If left in solution, the green rust layer oxidizes into α-FeOOH goethite. The corrosion process is: Fe → GR1(CO 3 2−) → α-FeOOH, without previous formation of ferrous hydroxide, as expected from the Pourbaix diagram of iron in carbonate-containing aqueous media. If removed from the solution and oxidized in the air, the green rust layer oxidizes into a mixture of ferrihydrite or δ-FeOOH, i.e. poorly crystallized hydrated ferric oxide, and of a compound that could be called ferric green rust which keeps, in spite of the oxidation of the Fe (II) ions, the original stacking sequence. Iron samples corroded in (0.1 mol1 −1 NaHCO 3 + 4 mol1 −1 NaCl) solutions are also covered with carbonate-containing green rust one layers and the chloride-containing green rust one, [Fe 3 staggered(II)Fe (III)(OH) 8][Cl· nH 2O]is not observed even though the ClHCO 3-ratio of the solution is as large as 40:1.

Diagnosis of Mixed Acid-Base Disordersin Diabetic Ketoacidosis

In diabetic ketoacidosis, a mixed acid-base disorder is suggested when the anion gap increase (delta AG) does not equal the bicarbonate decrease (delta HCO3), or when the delta AG/delta HCO3 ratio does not equal 1.0. It is widely assumed that delta AG/delta HCO3 is significantly different from 1.0 when it is less than 0.8 or greater than 1.2. The validity of these ratio limits were examined by analyzing a normal control group of 68 subjects and 27 diabetic ketoacidosis admissions that had no evidence of mixed disorders. In the 27 ketoacidosis admissions, regression analysis showed that delta AG was predicted to equal delta HCO3, as expected in pure anion gap acidosis: delta AG = 1.0 delta HCO3 (r = 0.744, p < 0.001). It was found that delta AG is significantly different from delta HCO3 when they differ by more than 8 mEq/L, and equivalently, delta AG/delta HCO3 is significantly different from 1.0 when it is less than (1.0 - 8/delta HCO3) or greater than (1.0 + 8/delta HCO3). These criteria from regression analysis suggested that 4% of the 27 pure anion gap acidoses, and 3% of the control group, had mixed disorders. In contrast, the ratio limits of 0.8 and 1.2 suggested 56% of the pure anion gap acidoses, and 94% of the control group, had mixed disorders. It was concluded that mixed disorders are overdiagnosed by the ratio limits of 0.8 and 1.2. Mixed disorders are more accurately detected by noting whether delta AG and delta HCO3 differ by more than 8 mEq/L.

Use of the anion gap in clinical medicine.

The anion gap (AG) in the serum equals the concentrations of Na-(Cl + HCO3). It is becoming increasingly useful in the interpretation of acid-base disorders and in the diagnosis of other conditions. In an acidemic patient, an elevated AG usually indicates the presence of an organic acidosis, rhabdomyolysis, nonketotic hyperglycemic coma, uremia, or certain intoxications. An increased AG with alkalemia suggests severe alkalosis with hemoconcentration or use of anionic antibiotics (eg, carbenicillin) or salts of organic acids (eg, citrate). An elevated AG with a normal serum pH could be an artifact caused by prolonged exposure of the serum sample to air before processing. A decreased AG with a normal serum pH may indicate hypoalbuminemia, cationic paraproteinemia, halide poisoning, or lithium intoxication. The delta AG/delta HCO3 ratio and the urinary AG may also be quite useful in analyzing complex acid-base disorders.

Analysis of the factors influencing peritubular PCO2 in the rat.

We have developed a mathematical model to assess the relative contributions of several factors to the high CO2 partial pressures observed in rat peritubular capillaries. This model is based on a single nephron and focuses specifically on the CO2 partial pressure differences (delta PCO2) between peritubular capillaries and the afferent arteriole. The model is formulated by writing steady-state mass balances for the glomerulus, proximal tubule, and peritubular capillaries in addition to equilibrium relationships for CO2, HCO3-, blood protein buffers, and hemoglobin carbamino compounds. Principal input parameters include glomerular blood flow rate, rates of HCO3- and water reabsorption, and the rate of metabolic CO2 production. Under conditions representative of normal Munich-Wistar rats, the model predicts delta PCO2 to be 4.1 mmHg, in approximate agreement with experimental observations reported elsewhere. Metabolic CO2 production is responsible for roughly half of this predicted delta PCO2, the remainder being attributable to reabsorption processes. In examining the sensitivity of delta PCO2 to changes in physiological conditions, we consistently found it to be inversely related to glomerular blood flow rate. The influence of changes in HCO3- reabsorption on delta PCO2 is variable and highly dependent on the arterial acid-base status and the ratio of HCO3- reabsorption to water reabsorption.