Acid-base Electrolyte Research Articles

Research Progress in Structure Evolution and Durability Modulation of Ir- and Ru-Based OER Catalysts under Acidic Conditions.

Green hydrogen energy, as one of the most promising energy carriers, plays a crucial role in addressing energy and environmental issues. Oxygen evolution reaction catalysts, as the key to water electrolysis hydrogen production technology, have been subject to durability constraints, preventing large-scale commercial development. Under the high current density and harsh acid-base electrolyte conditions of the water electrolysis reaction, the active metals in the catalysts are easily converted into high-valent soluble species to dissolve, leading to poor structural durability of the catalysts. There is an urgent need to overcome the durability challenges under acidic conditions and develop electrocatalysts with both high catalytic activity and high durability. In this review, the latest research results are analyzed in depth from both thermodynamic and kinetic perspectives. First, a comprehensive summary of the structural deactivation state process of noble metal oxide catalysts is presented. Second, the evolution of the structure of catalysts possessing high durability is discussed. Finally, four new strategies for the preparation of stable catalysts, "electron buffer (ECB) strategy", combination strength control, strain control, and surface coating, are summarized. The challenges and prospects are also elaborated for the future synthesis of more effective Ru/Ir-based catalysts and boost their future application.

Suppression of current-induced membrane discharge of bipolar membranes by regulating ion crossover transport

Bipolar membranes (BPMs) exhibit the unique capability to regulate the operating environment of electrochemical system through the water dissociation-combination processes. However, the industrial utilization of BPMs is limited by instability and serious energy consumption. The current-induced membrane discharge (CIMD) at high-current conditions has a negative influence on the performance of anion-exchange membranes, but the underlying ion transport mechanisms in the BPMs remain unclear. Here, the CIMD-coupled Poisson-Nernst-Planck (PNP) equations are used to explore the ion transport mechanisms in the BPMs for both reverse bias and forward bias at neutral and acid-base conditions. It is demonstrated that the CIMD effect in the reverse-bias mode can be suppressed by enhancing the diffusive transport of salt counter-ions (Na+ and Cl−) into the BPMs, and that in the forward-bias mode with acid-base electrolytes can be suppressed by matching the transport rate of water counter-ions (H3O+ and OH−). Suppressing the CIMD can promote the water dissociation in the reverse-bias mode, as well as overcome the plateau of limiting current density and reduce the interfacial blockage of salt co-ions (Cl−) in the anion-exchange layer in the forward-bias mode with acid-base electrolytes. Our work highlights the importance of regulating ion crossover transport on improving the performance of BPMs.

Polyoxometalate and ammonium polyphosphate induced bimetallic tungsten-based phosphides for electrocatalytic hydrogen production

Tungsten-based phosphide has gained significant traction in the field of electrocatalytic hydrogen evolution on account of its platinum-like characteristics, cost-effectiveness and exceptional electrical conductivity. In this work, bimetallic phosphide (WP/WCoP2@C) was prepared for hydrogen evolution reaction (HER) via high-temperature annealing and in situ phosphating procedure using the green phosphorus source ammonium polyphosphate (APP) without no toxic substances generated. WP/WCoP2@C exhibits satisfactory catalytic hydrogen evolution activity, with the overpotentials in acidic and alkaline environments of 151 and 138 mV, respectively, at current density reaching 10 mV cm−2. Moreover, WP/WCoP2@C shows favorable stability in the acid-base electrolytes for 36 h. This work provides experimental ideas for the green clean synthesis of tungsten-based phosphides for electrochemical small molecules transformation for sustainable energy generation.

Collaborative coupling catalytic interface enabling efficient hydrogen evolution in universal-pH electrolytes and seawater

Developing particularly effective and synergistic non-noble metal electrocatalysts for complex chemical processes remains an enormous challenge. Herein, the collaborative catalytic interface among rare earth compounds, bimetallic carbide, and N-doped carbon is demonstrated to accelerate the hydrogen evolution process in acid-base electrolytes and seawater. Therefore, the HER performance of the resultant electrocatalyst in both 1.0 M KOH and 0.5 M H2SO4 with the overpotentials of 70 and 79 mV, to achieve the current density of 10 mA cm−2. In addition, they also show excellent performance of HER in natural seawater and have good characteristics in catalytic activity and stability, which is reflected in the slight decrease of activity after the 5000 cyclic voltammetry (CV) cycle and almost no attenuation after electrolysis for 10 h. This work will pave a new way for collaborative coupling interface catalysis strategy to boost electrocatalytic hydrogen production in acidic, alkaline, and seawater.

STUDIES ON CORROSION BEHAVIOR OF POLISHED NICKEL SURFACE WITH RESIN WETTED BY DEEP EUTECTIC SOLVENT

As a material widely used in aerospace and energy development, the surface quality of nickel and its alloy will need to be improved urgently. Electrochemical polishing, as a surface treatment method, can smoothen the metal surface and improve its corrosion resistance. Strict environmental regulations have given rise to new electrochemical polishing techniques. In this paper, the electrochemical polishing of nickel was carried out using resin particles wetted by deep eutectic solvent (DES) as polishing medium. The surface morphology and roughness of polished nickel were characterized by scanning electron microscopy (SEM) and optical profilometer. In addition, electrochemical polarization curve and electrochemical impedance spectroscopy (EIS) were used to test the corrosion behavior of polished specimens in 3.5[Formula: see text]wt.% NaCl solution. The results show that the surface morphology of polished nickel shows grain boundary characteristics. The surface roughness Ra can be reduced from 0.612[Formula: see text][Formula: see text]m to 0.0913[Formula: see text][Formula: see text]m (under 30[Formula: see text]V voltage polishing 1[Formula: see text]h), and the corrosion current density can be reduced from 27.30[Formula: see text][Formula: see text]A[Formula: see text]cm[Formula: see text] to 12.15[Formula: see text][Formula: see text]A[Formula: see text]cm[Formula: see text]. Pitting potential in the polarization curve indicates that the pits at the grain boundaries are corroded due to the influx of corrosive chloride ions. This polishing method combines the resin with DES which can reduce the production of polishing liquid waste while avoiding the use of harmful acid-base electrolytes and effectively reduce the surface geometry uneven degree, improving the surface corrosion resistance.

Surgical Treatment of Gastric Malignancy in Chronic Kidney Disease Patient with Long-Term Haemodialysis

Background. Gastric cancer is the world 5th top malignancy, with treatment success largely conditioned by comorbidity. Patients with end-stage renal failure developed with chronic kidney disease could not expect a specialty cancer treatment before the advent of long-term haemodialysis.Aim. A case description of successful perioperative therapy and surgery in a long-term haemodialysis patient performed by a multi-specialty team of oncologists and transplantologists.Materials and methods. We case-illustrate surgical treatment options in a gastric cancer patient with long-term haemodialysis.Results and discussion. A specialty oncological treatment of end-stage renal failure patients requiring long-term haemodialysis is a complex multidisciplinary task feasible in hospitals equipped for different haemodialysis regimens. The treatment plan should be laid out by a multi-specialty team, as chronic kidney disease influences the choice of the drug class, dosage and administration mode. Moreover, such patients need laboratory (control of acid-base balance, haemoglobin, electrolytes, creatinine and urea) and clinical (body weight, liquid balance, etc.) monitoring.Conclusion. Perioperative management studies in gastric cancer and chronic kidney disease-comorbid patients under long-term haemodialysis is a promising area of combining eff ort in oncology and transplantation science. Further research is needed in this topic for data enrichment and analysis in complex comorbidity patients.

Cerium-polysulfide redox flow battery with possible high energy density enabled by MFI-Zeolite membrane working with acid-base electrolytes

A pH change can enable high-energy-density RFB (redox flow battery) in an aqueous medium. Nevertheless, a membrane to prevent the ion crossover is needed. This study adopted cerium and polysulfide in an acid-base combined electrolyte with an MFI-Zeolite membrane as a separator. The increased potential with pH change is described by the OCP (open circuit potential) difference, which varies by 0.8 V for the combination of acid-acid and acid-base electrolyte. A decrease of 350 mV at the redox peak potential of Ce3+/Ce4+ and a 10 mV negative potential shift for S42−/2S22− highlights the pH effect between the combination of acid-acid and acid-base electrolyte indicates the influence of pH leading in half-cell of anodic than the opposite cathodic side. The UV–visible spectral analysis for Ce3+ and S42− ions displacement shows that cerium and sulfur ions do not migrate to each other half-cell through an MFI-Zeolite membrane. As a result, the current efficiency of 94%, voltage, and energy efficiency of 40%–43% were attained at a current density of 10 mA cm−2. Moreover, the acid-base composition of the Ce/S system showed an energy density of 378.3 Wh l −1.

The Role of Uremic Intoxication in the Development of Cardiovascular Remodeling in Patients with Chronic Kidney Disease Stages 3a-5d

In recent decades, the prevalence of chronic kidney disease (CKD) in the population has a clear upward trend. This is due, first of all, to an increase in the frequency of occurrence of the main factors leading to its development: diabetes mellitus and arterial hypertension. The progression of CKD against the background of the action of these factors leads to a steady loss of the kidneys of their filtration capacity and the development of complications associated with this process. These include, first of all, metabolic and acid-base disorders, electrolyte abnormalities, uremic intoxication, overhydration, protein-energy wasting, sarcopenia and others. Most of them are involved in the development of endothelial dysfunction and the formation of cardiovascular remodeling (CVR), as a key component of the cardiorenal continuum. At the same time, there is a mutual negative influence of pathology of the cardiovascular system on renal function and manifestations of CKD on cardiovascular hemodynamics. This “vicious circle” leads to the development of end-stage renal disease and an increase in cardiovascular risk and mortality from diseases of the circulatory system in patients with advanced stages of CKD. In this connection, this work is devoted to the study of the role of uremic intoxication and, in particular, indoxyl sulfate, in the development of CVR in patients with CKD at different stages of the disease.

Study of Preventing the Alumina Dissolution and Metal Ion Migration in the Ceramic Membrane Divided-Electrochemical Cell Worked with High Acid-Base Electrolyte

The separator plays a key role in enhancing the performance of an electrochemical reactor. Polymeric ion-exchange membrane-like Nafion has been commercialized, but it has some disadvantages, such as durability and ion migration between the half-cells. In the present work, a ZSM-5 membrane (Pore size 0.55 nm) prepared by secondary growth on core–shell tubular ceramic supports was tested by measuring the stability and performing migration analysis in each half-cell of a divided tubular electrolysis reactor in high alkaline-acid aqueous solutions. An approximately 9000 h core–shell Zeolite tubular membrane (CSZTM) was robust when functioned at room temperatures in high acid and alkaline media because no obvious change in surface morphology was observed by scanning electron microscopy, X-ray diffraction, inductively coupled plasma—optical emission spectroscopy mass loss percent, and open porosity, and there were no large differences in the patterns. Ion migration was analyzed for more than 500 h in a divided tubular cell using CSZTM, and no migration was observed in both sides according to UV–visible spectroscopy. CSZTM was synthesized successfully, and its stability and ion migration were examined in an acid-alkaline aqueous solution in an electrochemical reactor.

CHANGES IN HYDROGEN INDEX AND BLOOD ELECTROLYTES DURING RECOVERY PERIOD AFTER BLOOD LOSS WITH FOLLOWING ADMINISTRATION OF MAGNETITE NANOPARTICLES

Magnetite nanoparticles are one of the extensively investigated and implemented into medical practice. They are known as having significant therapeutic potential in providing rapid recovery of hematological parameters after acute blood loss. Since the pathogenesis of acute blood loss, except of anaemia, includes other components (hypoxia, hypovolemia, acidosis), it is important to know how magnetite nanoparticles affect the parameters of these processes.
 The aim of this study was to investigate the effect of magnetite nanoparticles on changes in hydrogen index (pH) and blood electrolytes induced by acute blood loss. Materials and methods. The experiment was performed on 47 white male rats. Blood loss (25% of circulating blood) was simulated by puncture of the heart under the ether anesthesia. The nanoparticles’ solution (5-8 nm) was administered intraperitoneally immediately after the blood loss in a dose of 6.75 mg Fe/kg in a volume of at least 1 ml. In 3, 24 and 72 hours, and in 5 day interval, the blood pH and content of HCO3–, Na+, K+ and Ca2+ were checked. The data obtained were processed using one-way variance analysis ANOVA (Statistica for Windows 8.0). Results and discussion. It is shown that magnetite nanoparticles elevated the pH level in 3 hours, reduced in 24 hours and did not affect it in 72 hours and 5 days as compared to the control pathology. The administration of magnetite nanoparticles after 3 hours, 24 hours and 5 days resulted in increase in Na+ content compared to that in blood loss. An increase in the content of K+ took place after 24 hours as compared to the control pathology. Magnetite nanoparticles contributed to the normalization of Ca2+ after 72 hours. The content of HCO3– in all terms of observations ranged within normal limits, except for that in blood loss with magnetite nanoparticles introduced after 24 hours caused the increase of HCO3–in 1.2 times compared to the control pathology. Conclusion. Magnetite nanoparticles, administered to manage the acute blood loss syndrome, are able to modify the acid-base balance and electrolyte content in the blood for 5 days of recovery period that largely depends on the ability of non-iron to accelerate erythropoiesis and thus to restrain other components in the pathogenesis.

Acid-base, electrolyte and oxidative status in dairy cows at different stages of the production cycle

Previous studies in the field of acid-base and oxidative status in cows have mainly focused on the transition period (three weeks before and three weeks after calving). The aim of this study was to determine the differences in the parameters of acid-base and oxidative status and electrolyte balance in cows not only during the transition period, but also at other stages of the production cycle. Holstein-Friesian cows were divided into four numerically equal groups (n = 6): early lactating cows (9?2 days in milk - DIM), peak lactating cows (50?5 DIM), late lactating cows (170?10 DIM) and dry cows (10?1 days before calving). Venous blood samples were taken from the cows to analyze acid-base status, electrolyte concentrations and oxidative stress parameters, and to compare group means. Significantly higher pH was observed in early lactating cows than in late lactating cows. Sodium (Na+) concentration was significantly lower in early lactating and peak lactating cows compared to dry cows, while chloride (Cl-) concentration was also lower in late lactating cows compared to dry cows. Plasma glutathione peroxidase (GSH-Px) activity was higher in early lactating cows compared to peak lactating cows. Thus, the highest blood pH, lowest Na+ and Cl- concentrations and highest serum GSH-Px activity were observed in early lactating cows compared to other groups, indicating the highest metabolic and oxidative stress during this period. In conclusion, it would be useful to consider the inclusion of these parameters in standard health assessment procedures in intensive dairy production.

Combination of Acid-Base Electrolyte at Each Half-Cell with a Single Zeolite Membrane for Crossover Free and Possible Increased Energy Density in an All Aqueous Redox Flow Battery

Instead of an organic medium, a simple change in pH could lead to a high energy density redox flow battery (RFB). Besides, ion crossover and membrane optimization are problems that limit its commercialization. In this investigation, a zeolite-coated ceramic single membrane is adopted in an acid-base pH electrolyte combination for the vanadium (V4+/V3+)/sulfur (S4 2−/2S2 2−) (V/S) redox couple as a model system. First, the potential widening with a change in pH is explained by difference in OCP (open circuit potential) between the acid-acid and acid-base electrolyte combination that differs by 0.8 V. A 300 mV decrease in the V4+/V5+ redox peak potential and the 10 mV increase in the negative direction in the S4 2−/2S2 2− redox peak potential between acid-acid and acid-base electrolyte combination show the pH effect predominant in anodic half-cell than the cathodic half-cell. UV-visible analysis for the migration of vanadium and sulfur ions demonstrates no migration of vanadium and sulfur ions to each other half-cell via zeolite coated ceramic membrane. The current efficiency of 94%, voltage and energy efficiencies of 45%–50% are achieved under the given current density of 5 mA cm−2. In addition, the acid-base combination of V/S RFB system shows an energy density of 233.2 Wh l−1

Coronavirus diseases 2019 and kidney injury: a brief review based on current evidence.

Coronavirus diseases 2019 and kidney injury: a brief review based on current evidence.

Abstract 14494: Once You 1c It, You Can’t Unsee It: A Case of Flecainide Toxicity

Introduction: Flecainide is a class 1c antiarrhythmic commonly used for the treatment of atrial and ventricular arrhythmias in the absence of underlying structural heart disease. The significant proarrhythmic effects of the drug warrant familiarity with the drug and its toxicity. Flecainide overdose, whether intentional or iatrogenic, is a life threatening emergency with mortality rates as high as 22.5%. We present a case of intentional flecainide overdose and its management. Case: A 78-year-old man with a history of heart failure, paroxysmal atrial fibrillation on flecainide, presented to a local ED after a suicide attempt. He was initially hemodynamically stable and a 12-lead EKG revealed a wide-QRS bradyarrhythmia (See figure 1). Electrolyte panel showed normal potassium and pH. During transport to our tertiary cardiac intensive care unit, the patient declined and was critically ill on arrival. The diagnosis of flecainide toxicity was suspected and therapy was initiated on arrival. Despite therapy with sodium bicarbonate and fat emulsion, the patient continued to decline. Renal replacement therapy was started and the patient was evaluated for mechanical circulatory support. Ultimately, the patient’s family elected for palliative extubation. The patient’s flecainide level returned more than four times above the therapeutic range. Discussion: This case highlights the importance of a high index of suspicion when faced with a wide-QRS arrythmia in a patient with suspected antiarrhythmic overdose. The persistence of these rhythms after correction of acid-base abnormalities and electrolyte derangements should prompt aggressive, empiric treatment of potential overdose. The presence of electromechanical dyssynchrony in this context is an ominous sign and should prompt simultaneous evaluation for biventricular mechanical circulatory support concomitant with medical therapy for suspected overdose. Figure 1

Interlaboratory EQA programmes realized in 2017 by Centre for Quality Assessment in Laboratory Medicine

In 2017, the Center for Quality Assessment in Laboratory Medicine conducted, in accordance with the adopted annual schedule, 28 editions of interlaboratory tests as part of the general program and the central program. The general program included tests in the field of clinical chemistry, acid-base balance parameters and ISE electrolytes, hematology, coagulology and immunochemistry (basic, extended and cardiac markers). In the common chemical program, four editions of tests were carried out, evaluating 8 different control materials. The remaining programs were carried out with the frequency of 2 editions a year and evaluated only 4 different control materials, with the exception of the acid-base balance program and ISE electrolytes (6 control materials per year). General program tests were available to all MLD who performed routine testing of analytes within the scope of individual testing programs (over 1,500 medical diagnostic laboratories), and chemical tests under the central program, implemented for over 40 years, concerned about 250 selected laboratories. In all completed editions of the tests, a slight increase in the odometer of results assessed as correct according to the adopted assessment criteria was observed. In 2017, participants of the programs were provided with a new certificate format with annual regularity assessments and for the first time in a general program in the field of clinical chemistry, quality certificates were issued in accordance with the Regulation of the Minister of Health of 15 December 2017.

Effect of Bailing capsule on cellular immunity and renal function in patients with chronic renal failure CKD3-4

Objective To investigate the effect of Bailing capsule in the treatment of chronic renal failure (CRF). Methods A total of 120 patients with chronic renal failure CKD 3-4 who were admitted to Longhua hospital affiliated to Shanghai university of Chinese Medicine from January 2018 to May 2018 were randomly divided into control group and experimental group(n=60). The control group was given dietary control to regulate blood pressure, blood lipids, blood sugar. to correct anemia, improve acid-base imbalance and electrolyte imbalance, and the experimental group was given Bailing capsule on the basis of the control group. Continuous treatment for 3 months, comparing the total effective rate and renal function levels of the two groups, including serum creatinine (Scr), urea nitrogen (BUN), creatinine clearance (Ccr), T lymphocyte subsets and cytokine levels, including CD3+, CD4+, CD4+/CD8+, natural killer(NK) cells. Results The total effective rate of the experimental group after treatment was higher than that of the control group, and the difference was statistically significant (P 0.05). The renal function levels (Scr, BUN) of the two groups were better than those before treatment, and the experimental group was better than the control group, the difference was statistically significant (P<0.05). The level of Ccr after treatment was higher than that before treatment, and the experimental group was higher than the control group, the difference was statistically significant (P<0.05). The CD3+, CD4+, CD4+/CD8+, and natural killer (NK) cells were increased in the two groups after treatment. The difference between the two groups was statistically significant (P<0.05), and the experimental group had high T lymphocyte subsets. In the control group, the difference was statistically significant (P<0.05). Conclusions Bailing capsule has a good clinical effect in the treatment of CRF, which can improve renal function and enhance immune function. It has certain clinical application value. Key words: Kidney Failure, Chronic; CHINESE PATENT DRUGS

External quality assessment programs of laboratory test results conducted by the Central Center for Quality Research in Laboratory Diagnostics in 2018

In 2018, the Center for Quality Research in Laboratory Diagnostics conducted 22 editions under eight external quality assessment programs. In two programs (in the field of hematology and parameters of acid-base balance and electrolytes of ISE) the frequency of editing from two to four has been increased, gradually adapting the programs to the requirements of the Regulation of the Minister of Health of December 15, 2017 (Journal of Laws). As part of the extension of the program offer, the Central Center introduced 12 new analytes in the coagulology program and implemented a new external quality assessment program for HbA1c glycated hemoglobin controls. The Central Center also implemented in 2018 a new procedure for transporting samples of control materials to laboratories. For the first time, the parcels were delivered by courier. In all programs implemented in 2018, higher percentages of correct results were obtained according to the adopted criteria and annual regularity assessments comparable to 2017. Very satisfactory results were also obtained for glycated hemoglobin, HbA1c – a pilot program implemented in 2018.

Particulars of the perioperative management of patients with end stage renal disease during hip and knee replacement arthroplasty

The world prevalence of chronic kidney disease (CKD) stages 1 to 5 ranges from 11.7 to 15.1%. Incidence of fractures in patients with CKD stage 5 is 5-fold higher than that in the general population, which is related to mineral metabolism disorders, secondary hyperparathyroidism, and osteoporosis. By damaging multiple organs and systems, CKD triggers a whole pathological cascade. There are hematopoietic abnormalities, cell lineages, direct toxic effect on blood cell elements, with simultaneously increased risk of bleeding and a high and extremely high risk of thrombi formation and thromboembolic complications. Calcium and phosphorus metabolism disorders lead to calcification and mineralization of vasculature, myocardium and heart valves; progressive renal dysfunction affects the course of heart and vessel diseases, aggravating their clinical manifestations. Cardiovascular disorders become the main cause of death of such patients, and the development of pulmonary hypertension is associated with increased morbidity and mortality. At the same time, protein and energy deficiencies do occur, with disturbance of the acid-base balance, water and electrolyte balance; uremic toxins exert unhealthy effects on the gastrointestinal tract. Various extra-renal pathologies, specific pharmacokinetics, regimen and frequency of renal replacement therapy needed to maintain an adequate volume status make it necessary to thoroughly prepare the patients for surgery and define special requirement to perioperative management in arthroplasty. Currently, there are no guidelines on the perioperative management of this patient category. In this review article we consider specifics and particulars of preoperative, intraoperative and postoperative management of the end stage CKD patients during knee and hip replacement arthroplasties.

Arterial, Mixed Venous or Central Venous Hemogasometry and End Tidal CO2 in Dogs under Different Hemodynamic States

Background: Hemogasometric analysis is used in the interpretation of acid-base balance (ABB) and to access pulmonary ventilation. Already mixed venous oxygen saturation obtained at pulmonary artery correlates with tissue oxygenation. However, both samples can be difficult to access because of the difficulties in arterial and pulmonary catheterization. The aim of this study was to evaluate the feasibility of replacing the arterial and mixed venous bloods, the end tidal pressure of carbon dioxide (EtCO2) and central venous blood in the analysis of pulmonary ventilation, tissue oxygenation and ABB in dogs under different hemodynamic states.Material, Methods &amp; Results: Nine dogs were used with an average weight of 19.6 ± 1.3 kg, anesthetized with isoflurane at 1.4 V% diluted on oxygen 60% (Baseline), and subsequently undergoing mechanical ventilation (MV) and the hypodinamic state (Hypo) with isoflurane at 3.5V% and mean arterial pressure (MAP) lower than 50 mmHg and hyperdynamic state (Hyper) by dobutamine infusion at 5 μg/kg/min and with MAP 30% higher than baseline. For each time allowed a 15 min of stabilization by each hemodynamic status. Simultaneously were collected samples of 0.6 mL of arterial blood by metatarsal artery, mixed and central venous blood by pulmonary artery and right atrium for hemogasometric analysis. To access lung function we correlated and compared the EtCO2 values obtained by gas analyzer with expired carbon dioxide pressure in the arterial blood (PaCO2), mixed venous blood (PmvCO2) and central venous blood (PcvCO2). For the interpretation of tissue oxygenation we correlated and compared the values of mixed (SmvO2) and central (ScvO2) venous oxygen saturation. For the acid-base balance we used the correlation of potencial hydrogen (pH); carbon dioxide pressure (PCO2); bicarbonate ion (HCO3-); base excess (BE); anion GAP (AG); sodium ions (Na+), chlorine ions (Cl-), potassium ions (K+) and ionized calcium (iCa) of arterial (a) mixed venous (mv) and central venous (CV) bloods. Statistical analysis was performed using ANOVA-RM followed by Dunnet test for differences between times and Tukey’s test for differences among the samples (P ≤ 0.05). Pearson correlation analysis was performed using linear regression and for comparison methods we used the Bland-Altman analysis The EtCO2 values correlated (r = 0.87) and were according to Bland-Altman analysis with PaCO2 values (mean difference of -1.6 ± 2,9 mmHg for PaCO2. There were no differences (P ≤ 0.05) from SmvO2 and ScvO2. ScvO2 correlated (r = 0.91) with SmvO2 at different hemodynamic states and with a mean difference of -0.4 ± 2.5%. Both venous bloods were correlated with the analysis of arterial blood acid-base balance and electrolytes in different hemodynamic states. However, the ionized calcium levels were 40% lower in arterial blood.Discussion: EtCO2 measurement depends of monitor technology and proper pulmonar ventilation and perfusion. In this study the limiting factor in replacing the PaCO2 hair EtCO2 was spontaneous ventilation because in this state pulmonary ventilation is compromissed. With the use of MV was possible get up similar results in the pulmonar function analysis using the EtCO2 and PaCO2. The use of central venous blood instead mixed venous blood at oxygen saturation analysis provided adequate estimate this parameter. This being easier and less invasive technique. ABB was possible with all samples with own reference values for venous and arterial samples. This is an interesting result for critical patients where the arterial sample is difficult. In electrolytes the sample was indifferent except for calcium because pH interfere in this values. It was conclude that the values of EtCO2 and central venous blood are correlated and can replace arterial and mixed venous bloods in the analysis of lung function, tissue oxygenation and acid base balance.

Evaluating the Potential for Hydrogen Production with Donnan-Driven Multi-Ion Exchange Membrane Based Systems

Reverse electrodialysis (RED) is a membrane-based electrochemical system used for harvesting salinity gradient energy (2.6 TW) through the mixing of sea and river water at global estuaries[1]. This is accomplished through a series of anion and cation exchange membranes (AEM and CEM), which drive electrical energy production at adjacent redox electrodes. As more membranes are added to the system, the generated potential increases which increases current production. Galvanic operation of RED for electricity production has been demonstrated, but electrical power density and limiting current density are typically less than 0.2 W/m2 and 10 A/m2 [2]. Here, we propose to produce hydrogen with a RED cell, through operating in an electrolytic mode. This multiple membrane electrolysis process is partially driven by the membranes through their “Donnan-potential”, and partially driven by additional electrical energy input [3-6]. By pushing the RED cell into the electrolytic region, high current density needed for hydrogen production, can be achieved. Here, hydrogen production using an electrolytic RED is evaluated with a varying number of cell pairs (1 to 10) and with acidic, neutral and basic electrolytes at a fixed 10 mA/cm2. Under neutral conditions, the resulting voltage obtained from the RED cell decreased from 2.1± 0.1 V to 1.2±0.2 as the number of cell pairs increased from 1 to 10. In addition, the energy conversion efficiency of the system decreased due to the increase in mixing energy (ΔGmix.) from 130.6 J to 1203.2 J at higher cell pairs. When the cell was operated with an acidic cathode and basic anode, the applied voltage and energy consumption decreased by 45% compared to neutral pH. In addition, the current density achieved was 4x greater at a voltage 1 cell pair. The hydrogen to electrical energy ratio increased from to 100% at 2 mA/cm2 when the number of cell pairs increased from 1 to 10 with neutral electrolytes. This ratio increased by 3x under acid-base electrolytes. Logan, B.E. and M. Elimelech. Nature, 2012. 488(7411): p. 313-319.Zhu, X., He, W., & Logan, B. E. (2015). Reducing pumping energy by using different flow rates of high and low concentration solutions in reverse electrodialysis cells. Journal of Membrane Science, 486, 215-221.Hatzell, M.C., I. Ivanov, R.D. Cusick, X. Zhu, and B.E. Logan. Physical Chemistry Chemical Physics, 2014. 16(4): p. 1632-1638.Nazemi, M., Zhang J., Hatzell M.C., “Harvesting Natural Salinity Gradient Energy for Hydrogen Production through Reverse Electrodialysis (RED) Power Generation”, J. Electrochem. En. Conv. Stor., 2017; DOI: 10.1115/1.4035835.Hatzell, M.C., X. Zhu, and B.E. Logan. ACS Sustainable Chemistry & Engineering, 2014. 2(9): p. 2211-2216.Nazemi, M., Padgett, J., and Hatzell, M.C. (2017). Acid/Base Multi‐Ion Exchange Membrane‐Based Electrolysis System for Water Splitting. Energy Technology.