Indirect Reaction Research Articles

Effect of Ti-Si-Fe alloy on the nitriding behavior of Si powder

Adding Ti-Si-Fe alloy to Si powder reduced the complete nitriding temperature of Si from 1450 °C to 1300 °C, greatly reducing the nitriding temperature of Si powder and the formation temperature of Si3N4 whiskers. At low temperature, Fe in Ti-Si-Fe alloy damaged the SiO2 film on the surface of Si and produced SiO (g), which was conducive for the indirect and direct nitridation of Si. The density functional theory (DFT) calculation results showed that the energy levels of SiO (g) molecules adsorbed by Fe broadened and moved towards lower energy levels, resulting in a decrease in the bonding strength and an increase in reaction activity of SiO (g) molecules. It was beneficial for the indirect nitridation reaction of 3SiO (g)+2N2 (g)=Si3N4 (s)+3/2O2 (g), and promoted the formation of α-Si3N4 whisker. The liquid phase formed by increasing temperature and Ti-Si-Fe alloy addition promoted the direct nitridation of Si. The activation energy of TiSi2 and Ti-Si-Fe alloy nitridation was 78.42 (KJ/mol) and 14.97 (KJ/mol), respectively. The nitridation of Ti-Si-Fe alloy was easier, and the pores and cracks generated by Ti5Si3 and TiSi2 step-by-step nitridation at low temperature in Ti-Si-Fe alloy provided pore channels for N2 transport and sufficient nitrogen for Si nitridation.

Adsorption effects of electron scavengers and inorganic ions on catalysts for catalytic oxidation of sulfamethoxazole in radiation treatment

This study aimed to investigate adsorption effects of electron scavengers (H2O2 and S2O82−) on oxidation performance for mineralization of sulfamethoxazole (SMX) in radiation treatment using catalysts (Al2O3, TiO2). Hydrogen peroxide (H2O2, 1 mM) as an electron scavenger showed weak adsorption onto catalysts (0.012 mmol g−1-Al2O3 and 0.004 mmol g−1-TiO2, respectively), leading to an increase in TOC removal efficiency of SMX within the absorbed dose of 30 kGy by 12.3% with Al2O3 and by 8.0% with TiO2. The weak adsorption of H2O2 onto the catalyst allowed it to act as an electron scavenger, promoting indirect decomposition reactions. However, high adsorption of S2O82− (1 mM) onto Al2O3 (0.266 mmol g−1-Al2O3) showed a decrease in TOC removal efficiency of SMX from 76.2% to 30.2% within the absorbed dose of 30 kGy. The high adsorption of S2O82− onto the catalyst inhibited direct decomposition reaction by reducing adsorption of SMX on catalysts. TOC removal efficiency for Al2O3 without electron scavengers in an acidic condition was higher than that in a neutral or alkaline condition. However, TOC removal efficiency for Al2O3 with S2O82− was higher in a neutral condition than in other pH conditions. This indicates that the pH of a solution plays a critical role in the catalytic oxidation performance by determining surface charges of catalysts and yield of reactive radicals produced from water radiolysis. In the radiocatalytic system, H2O2 enhances the oxidation performance of catalysts (Al2O3 and TiO2) over a wide pH range (3–11). Meanwhile, S2O82− is not suitable with Al2O3 in acidic conditions because of its strong adsorption onto Al2O3 in this study.

High-Efficiency Polishing of Polymer Surface Using Catalyst-Referred Etching

Previously, we developed an abrasive-free polishing technique called catalyst-referred etching (CARE) for inorganic materials. In this method, the topmost site of the workpiece surface is preferentially removed via an indirect hydrolysis reaction promoted by a metal catalyst. In this study, we proposed applying the CARE method to polymer material polishing and demonstrated the polishing characteristics. Using the CARE method, polycarbonate, which has an easy cleavage of ester bond via hydrolysis, was polished, resulting in the smoothness of the surface roughness below 1.0 nm. Based on the surface observations, the removal mechanism was estimated as follows. Molecule chains are entangled to form clusters constituting the polymer surface and help determine the surface roughness. In the CARE method, the top of this cluster was selectively removed, thus creating a smooth surface. Polymers with C–C bonds, such as polymethyl methacrylate and fluorinated ethylene propylene, were also smoothed using the CARE method. These results indicate that the CARE method is highly effective in polishing polymer materials.

Sudden Secondary Sensorineural Hearing Loss Following Hand, Foot, and Mouth Disease in an Adult Patient: A Case Report.

Introduction: Sudden sensorineural hearing loss (SSNHL) can present as sudden hearing loss within 72 hours. Studies have shown that viral infection, including direct invasion, indirect reactions, stress responses, and immune-mediated hearing loss, is the main cause of SSNHL. Viral infection may play an important role in SSNHL by causing injury to the inner ear through blood or cerebrospinal fluid. In this article, we describe an adult case of SSNHL following hand, foot, and mouth disease (HFMD). Case Report: A 34-year-old man presented with sudden hearing loss in the right ear 4 days after HFMD onset. Tinnitus, ear fullness, and a slightly heavy head appeared synchronously as accompanying symptoms. Before 6 days, he had a fever for 2 days (the highest temperature was 39.4°C), followed by vesicles in the oral mucosa and papules on the hands and feet after cohabitation with his child diagnosed with HFMD.

Comparison of immunological and molecular methods for laboratory diagnosis of ocular toxoplasmosis in blood, serum and tears in Brazil.

Ocular toxoplasmosis (OT) is caused by protozoan T. gondii. Ophthalmological examination is considered the gold standard for OT diagnosis, and laboratory tests are used for diagnostic confirmation. However, these tests can present different results, which change depending on their basis, on sample type and on patients' clinical alteration. Thus, the aim of the present study is to assess immunodiagnostic and molecular techniques applied in blood, serum and tear fluid to diagnose T. gondii infection in patients seen at an Ophthalmology Clinic. In total, 160 patients were included in the study, 40 of them had OT with active lesions (G1); 40 had OT with healed lesions (G2), 40 had non-toxoplasmic uveitis (G3) and 40 had no ocular alterations (G4). Serum samples were subjected to Immunoenzymatic Assay (ELISA) and to Indirect Immunofluorescence Reaction (IFAT) to search for anti-T. gondii IgM and IgG. Tear fluid samples were analyzed through ELISA for IgA research. All blood and tear fluid samples were subjected to conventional polymerase chain reaction (cPCR) and in a Nested PCR model for T. gondii DNA amplification with targets B1, GRA7 and REP 529. IgG and IgM anti-T. gondii was detected in serum samples from 106 and 15 patients, respectively, when combining ELISA and IFAT results. Anti-T.gondii IgA antibodies were detected in 9.2% of the tear material. Nested PCR with GRA7 target showed higher positivity in blood samples (24.4%); Nested PCR with B1 target showed a higher frequency of positivity in tears (15%). Biological samples of patients with active lesions showed the highest positivity frequencies in all immunodiagnostic assays, as well as in most PCR models. The present results highlighted the need of associating techniques with different fundamentals to confirm OT diagnosis. Furthermore, further tear fluid analyses should be performed to validate this biological material as lesser invasive alternative for the more accurate OT diagnosis.

Formation of OH Radicals on BiVO4–TiO2 Nanocomposite Photocatalytic Film under Visible-Light Irradiation: Roles of Photocatalytic Reduction Channels

In this study, we investigated the effects of H2O2 addition on OH radical formation on the surfaces of visible-light-irradiated BiVO4–TiO2 nanocomposite photocatalysts. Additionally, we examined the possible roles of OH radicals formed by the reduction reaction of H2O2 on the visible-light-irradiated surfaces of photocatalytic BiVO4–TiO2 nanocomposites. The BiVO4–TiO2 nanocomposite photocatalysts were prepared by mixing a BiVO4 photocatalytic film with commercially available semiconductor particulate TiO2 photocatalysts. By removing oxygen gas from the photocatalytic reactor, the effects of oxygen molecules on OH radical formation during the visible-light irradiation of BiVO4–TiO2 nanocomposite photocatalysts were examined. During visible-light irradiation, BiVO4 and BiVO4–TiO2 photocatalysts play different roles in OH radical formation because of two characteristic reduction reaction channels: (a) the direct reduction of H2O2 on photocatalytic surfaces and (b) the indirect reduction reaction of H2O2 by superoxide radical anions (O2−).

Diagnóstico molecular de infecção por Ehrlichia canis e Babesia vogeli e diagnóstico sorológico de infecção por Neospora caninum e Toxoplasma gondii em cães provenientes do município de Cândido Sales-BA e microrregião

ABSTRACT The occurrence of Toxoplasma gondii, Neospora caninum, Ehrlichia canis and Babesia vogeli in dogs from the municipality of Cândido Sales, Bahia, was investigated. Total and peripheral blood samples were obtained from 131 dogs. Blood smears were performed to check for morulae. Toxoplasma gondii and N. caninum infections were determined by an Indirect Immunofluorescence Reaction. Nested-PCR and PCR were used for the diagnoses of E. canis and B. vogeli infections, respectively. Additionally, the risk factors associated with infection by these agents were analyzed. The frequency of infection was 70.2% for N. caninum, 67.9% for T. gondii and 37.4% for E. canis. None of the dogs tested positive for B. vogeli. Morulae of Ehrlichia spp. were identified in two animals and the piroplasm in one animal. Age (> 3 years) was considered a risk factor for infections by E. canis and N. caninum and the rural habitat for infections by N. caninum. Co-infections were frequent, mainly with N. caninum and T. gondii (45.03% of dogs). Ehrlichia canis infection was significantly associated with N. caninum and T. gondii infection. These findings indicated a high occurrence of T. gondii, N. caninum, and E. canis in the studied region.

PC Kz is the novel human prostate cancer model in vitro and in vivo

BACKGROUND: The use of relevant in vitro and in vivo model systems is important in preclinical studies of anticancer agents. The process of creating tumor models is methodically complicated and has a number of disadvantages. Among tumor models of prostate cancer, the most accessible are 2D models (DU145, 22Rv1, PC3, LNCaP, VCaP cell lines), their xenograft models in immunodeficient mice and some patient-derived xenograft models. However, this panel of experimental models is not perfect and needs further expansion.
 AIM: To create a new preclinical prostate cancer model, characterize it (morphology, tumorigenicity, tumor growth kinetics in vivo, verification of prostate-specific membrane antigen expression status, testosterone production, sensitivity to CYP17A1 inhibitors), and develop resistance to the steroid CYP17A1 inhibitor — abiraterone.
 METHODS: CYP17A1 expression in PC Kz cell line was evaluated by reverse transcription polymerase chain reaction. Testosterone concentration was determined with an enzyme-linked immunosorbent assay. The sensitivity to antitumor agents was studied with the MTT test. Tumorigenicity was evaluated by transplantation of PC Kz cell line into Balb/c nude mice. The prostate-specific membrane antigen expression status was assessed using the indirect reaction of surface immunofluorescence.
 RESULTS: The PC Kz cell line is characterized by a high level of CYP17A1 messenger RNA expression, comparable to that of the commercial 22Rv1 cell line. Immunophenotypic analysis demonstrated negative prostate-specific membrane antigen expression status of PC Kz cell line. A significant decrease (18%) in testosterone concentration in vitro was found, compared to the value in the control. This effect can be associated with the suppression of CYP17A1 gene expression.
 The studied PC Kz cell line is tumorigenic in Balb/c nude mice (100% tumorigenicity was detected during the first passage at a transplantation dose of 107 cells/mouse). A pathomorphological study of the structures of the obtained subcutaneous PC Kz xenografts verified their identity to the histological image of human prostate cancer. Furthermore, PC Kz/AA cell line was obtained, resistant to abiraterone; the index of resistance was 3.4.
 CONCLUSION: The derived PC Kz cell line was adapted for in vitro and in vivo growth, characterized by the main biological parameters, and can be recommended as an adequate test system to use in preclinical studies of new antitumor agents for the human prostate cancer treatment.

Construction of Z-scheme 0D/2D In2O3/ZnIn2S4 nanocomposite for photocatalytic hydrogen peroxide production and its mechanism

Photocatalytic production of hydrogen peroxide (H2O2) has gained significant attention as a sustainable technique in recent years. In this work, 0D/2D In2O3/ZnIn2S4 (ZISIO) Z-type heterojunction was successfully constructed using a calcination - solvothermal process,and its chemical composition, optical properties and photocatalytic mechanism were investigated. The In2O3/ZnIn2S4 nanocomposite photocatalysts exhibited excellent catalytic activity. After 100 min of visible light irradiation, the best performing sample (ZISIO60) showed the highest hydrogen peroxide concentration of 982.61 μmol L−1 in the solution. The concentration exhibited a 3.44-fold and 44.22-fold increase in comparison to that of prepared In2O3 and ZnIn2S4, correspondingly. The active species capture experiment results and Electron Spin Resonance spectra demonstrated that photocatalytic hydrogen peroxide production pathway of the prepared heterojunctions was a two-step single-electron indirect oxygen reduction reaction. In conclusion, the reported In2O3/ZnIn2S4 heterojunctions exhibit considerable catalytic activity and provide a reliable strategy for photocatalytic hydrogen peroxide production via photocatalysis.

The Role of Anti-DFS70 in the Diagnosis of Systemic Autoimmune Rheumatic Diseases

The diagnosis of systemic autoimmune rheumatic disease (SARD) or its exclusion is carried out taking into account the results of immunological studies, primarily antinuclear antibodies (ANA) and specific autoantibodies. Often, during ANA analysis via indirect immunofluorescence reaction on cellular and tissue substrates, a dense fine speckled 70 (DFS70) fluorescence pattern is observed. Studies on the diagnostic significance of antibodies to anti-DFS70 allow for optimizing the stepwise diagnosis of SARD. Currently, a two-step strategy for laboratory diagnostic investigation is recommended: in the first step, ANA screening is performed, and in the second step, patients with positive results undergo confirmatory tests to detect specific antibodies against individual nuclear antigens. The detection of anti-DFS70 in ANA-seropositive patients without clinical and/or other specific serological markers characteristic of a particular disease within the SARD group may be considered a negative prognostic marker. Also, in the process of decision making in clinical practice, we should remember that anti-DFS70 can be found in the blood of patients with a different, non-SARD pathology and that most people showing anti-DFS70 are healthy individuals.

One-step solvothermal synthesis of MoS2@Ti cathode for electrochemical reduction of Hg2+ and predicting BP neural network model

Although mercury is one of the heavy metal pollutants that endanger human health and the environment, it is also an essential raw material needed for industrial development. We try to use electrochemical reduction method to realize the resource utilization of mercury. MoS2@Ti electrodes were prepared using a one-step solvothermal method, and XRD, XPS, SEM and EDS were used to analyze the MoS2 powder. The prepared highly reactive MoS2@Ti electrode was used as a cathode to electrochemically reduce the mercury-containing solution. After a series of single-factor experiments, under the conditions of stirring rate of 400 r/min, electrode spacing of 20 mm, constant potential of 2 V and electrolytic time of 2 h, the removal efficiency of Hg2+ in 10 ∼ 50 mg/L HgSO4-10 % H2SO4 solution reached 94.5 % or above. The reaction mechanism of MoS2@Ti was investigated mainly by using the indirect reaction of superoxide radicals and hydrogen radicals to achieve the reduction of Hg2+. And the MoS2@Ti electrode can still reach 80.0 % removal efficiency after five times of repeated use. A neural network model was used to predict the efficiency of Hg2+ reduction in this system with a high accuracy of RMSE 1.3049 and R2 0.9511. The above study contributes to the realization of the resource utilization of mercury.

Photoelectro-catalytic oxidation of monoethanolamine: From the study of electrooxidation mechanism to the development of high-efficient Ni-based photoelectro-catalysts

Monoethanolamine (MEA) electrooxidation occurring on Ni catalyst has proven to be a viable tactics for simultaneous MEA degradation and energy recovery. However, the excessively large overpotential (1505 mV) on Ni catalyst either causes high electricity consumption when acquiring H2 from MEA-containing electrolyzer or leads to low energy output when extracting electricity from direct MEA fuel cell. In this context, the reaction mechanism of MEA electrooxidation on Ni-based catalyst is deciphered at first by employing a specially designed three-step electrochemical procedure and in-situ Raman spectroscopy. Electrochemical data deconvolutions indicate the indirect electrochemical-chemical reaction path, via Ni(OH)2/NiOOH mediator, occupies ∼2.5 % of the total catalytic current density at 0.55 V vs. Ag/AgCl and the direct oxidation of MEA ranks the rest ∼97.5 %. To decrease the onset potential of MEA oxidation, a photoelectric-catalytic system including high-efficient Ni-based photoelectric-catalyst, where Ni is intimately coated on TiO2 by in-situ photodeposition to achieve the shortest carrier transport channel between Ni(OH)2 and TiO2, is developed. Results show the overpotential of MEA electrooxidation under illumination significantly drops to 255 mV. Such a Ni@TiO2/FTO electrode also exerts excellent durability toward MEA oxidation.

Immunological and epidemiological effectiveness of tularemia vaccination in the Donbass region

Objective: to evaluate the epidemiological and immunological efficacy of tularemia vaccination in the Donbass region from 1991 to the present.Materials and methods: data on the incidence of tularemia, immunization coverage of the population, results of intradermal tests with tularin, agglutination reaction and indirect hemagglutination reaction with tularemia antigen were analyzed.Results: since 2012, immunization against tularemia has not been carried out on the territory of the republic. Since 2015, this approach has resulted in the emergence of foci with multiple cases of human tularemia. Cases were registered on the territory of natural foci of Novoazovsky and Yasinovatsky districts. Since 2017, immunization of the population in enzootic territories has been resumed, planning and selection of contingents to be vaccinated was carried out in a differentiated manner. According to epidemic indications, 400 people were vaccinated from among those at risk of contracting tularemia. In 2020– 2022 vaccination was not carried out. In the five months of 2023, 520 people were vaccinated against tularemia, 80 people were revaccinated.Conclusions: the use of tularemia vaccine in the Donetsk region for 70 years led to the containment of tularemia, demonstrating the epidemiological and immunological effectiveness of specific immunoprophylaxis. The armed conflict and the cessation of vaccination led to an increase in the activity of the epidemic process in natural foci among animals and a significant increase in the incidence of tularemia in humans.

Hydroxyl-groups engineering of triazole-based polymers for efficient photocatalytic hydrogen peroxide production

Photocatalytic hydrogen peroxide (H2O2) production via indirect two-electrons oxygen reduction reaction (indirect 2e−ORR) is severely limited by the unsatisfactory O2/H+ mass transfer and slow interfacial charge transfer efficiency. Herein, side-engineered triazole-based polymers (TZPs) are reported for efficient photocatalytic H2O2 production without sacrificial agent. The photoelectric properties, mass transfer and photocatalytic activities can be tuned by the distribution of hydroxyl groups on the benzenetricarboxaldehyde ring of TZPs. Theoretical calculations reveal that the asymmetric 2-hydroxyl-1,3,5-benzenetricarboxaldehyde monomer renders TZP-OE the largest dipole moment (2.5814 Debya) and the lowest first excited state index (3.654 eV). Moreover, the hydroxyl group optimizes the H2O wettability of TZPs. Benefiting from the enlarged intermolecular polarization-induced built-in electric field and excellent hydrophilicity, TZP-OE exhibits excellent photocatalytic H2O2 evolution rate of 1618 μmol/L under visible light irradiation, which is 3.5 times that of TZP-NE. Therefore, side-group engineering provides a new approach for the regulation of catalyst structure and photocatalytic activity.

New brucellosis erythrocyte diagnosticum for IHT in comparison with other serological methods (SAT, CFT, RBT and IDT)

Relevance. Brucellosis is registered in many countries of the world, including Russia. The most unfavorable situation in the Russian Federation has developed in the Southern and North Caucasus Federal Districts. In the first place among the number of identified sick animals is the Dagestan Republic, where, despite the efforts of veterinary specialists, it is not possible to reduce the number of oci of brucellosis. With the help of classical methods (SAT, CFT), only 70% of animals infected with brucellosis can be detected. In this regard, domestic and foreign researchers have done a lot of work to improve existing and develop new diagnostic tools and methods.Methods. One of the most sensitive methods for the diagnosis of brucellosis is the indirect hemagglutination reaction (IHT). In comparative tests in IHT, with an improved antigen, good results were obtained.Results. The possibility of obtaining a highly active erythrocyte diagnosticum has been established with the combined use of two new surfactants: Progress products manufactured by AMC Media LLC (LosinoPetrovsk, Moscow region) and sodium dodecyl sulfate. The most rational parameters of the use of detergents for the treatment of brucella suspension and their optimal concentrations have been determined. It was found that IHT with a new antigen is specific and highly sensitive, compared with other serological reactions.

Determination of primary and secondary oxidation products in vegetable oils with gold nanoparticle based fluorometric turn-on nanosensor: A new total oxidation value

Oxidation of fats and oils gives rise to lipid hydroperoxides as primary oxidation products (POPs) and carbonyl compounds as secondary oxidation products (SOPs). Here, we report the sensitive detection of POPs and SOPs (oxidation products) involving direct and indirect redox reactions with iodide ions, respectively, using the fluorophore probe (fluorescein-5-isothiocyanate-gold nanoparticles; FITC-AuNPs). Iodide released the fluorescent FITC from FITC-AuNPs in the turn-on mode. In case of SOPs, an indirect iodide determination was made through the use of chloramine-T as carbonyl reagent. To various vegetable oil samples, deep frying process (at 160 °C, simulating frying conditions) and soft oil oxidation (at 100 °C, simulating cooking conditions) were carried out for a period of time (1, 5 and 10 days). Total content of POPs varied between 4.00 and 5.70 g TBHP (t-butylhydroperoxide)/kg oil, and the amount of SOPs was found as 1.12–4.11 g t-2-nonenal/kg oil in non-oxidized oil samples. The proposed method was validated against FOX and p-anisidine value (p-AV) assays. Sensory analyses (taste, color, smell and appearance) results of non-oxidized and deep-fried oil samples were consistent with those of the proposed FITC-AuNP nanosensor. Finally, a new total oxidation (TOD) value (expressed as iodide equivalent meq/kg oil) was proposed to determine the overall oxidation state and quality of the oils. Our proposed TOD value is not only mathematically precise with respect to its units (i.e. POPs and SOPs are added up in the same equivalent units to obtain TOD) but also is in better accordance with the results of sensory analysis.

Sequential Process of Electro-Oxidation Followed by UV Photolysis (EO/UV) as a Simple Advanced Oxidation Process

ABSTRACT A sequential process of electro-oxidation followed by UV photolysis (EO/UV) was proposed as a simple advanced oxidation process. A boron-doped diamond (BDD) anode was used for electrolysis. A series of experiments revealed that the EO/UV significantly enhanced 1,4-dioxane degradation rate against single electro-oxidation and single UV photolysis. In the EO/UV of tap water, reactive radicals produced through UV photolysis of electrochemically generated ozone and free chlorine contributed to 28–53% of 1,4-dioxane degradation and the rest of the contribution was occupied by anodic oxidation. Indirect and direct ozone reactions did not take part in the 1,4-dioxane degradation. The energy efficiency of EO/UV was superior to that of single electro-oxidation at a higher current density and was stable in the electrolytic current range tested. Consequently, EO/UV was more effective in the rapid removal of 1,4-dioxane under an unsteady pollutant loading than the single electro-oxidation.

Влияние внутриклеточной регуляции метаболизма на популяционный состав лимфоцитов периферической крови человека

Metabolic activity has a significant impact on the differentiation, proliferation and functioning of T cells. Different lymphocyte subpopulations use, to varying degrees, glycolysis and mitochondrial metabolism, whose main regulators are hypoxia-inducible factor 1-alpha (HIF-1α) and sirtuin 3 (SIRT3), respectively. The purpose of this paper was to study changes in the population composition of peripheral blood lymphocytes in humans depending on the level of the intracellular metabolic regulators SIRT3 and HIF-1α. Materials and methods. 227 residents of the city of Arkhangelsk and the Arkhangelsk Region were examined (mean age 42 ± 11 years). Absolute lymphocyte count was determined using the Sysmex XS 500i haematology analyser, while CD3+, CD4+, CD8+, CD10+, CD25+ and CD95+ phenotypes content, by indirect immunoperoxidase reaction. Intracellular adenosine triphosphate (ATP) concentration was measured using the luciferase bioluminescence method. HIF-1α and SIRT3 concentrations were measured in lymphocyte lysate using enzyme immunoassay. To divide the total sample into groups according to SIRT3 and HIF-1α content, k-means clustering was utilized. Results. Changes in SIRT3 and HIF-1α intracellular concentrations correlated with ATP concentration. It was found that in the group with high HIF-1α content, the proportion of CD4+, CD8+, CD10+ and CD25+ lymphocytes was greater than in the group with high SIRT3 concentration, which had a greater proportion of CD95+ lymphocytes. Thus, the content of intracellular metabolic regulators that regulate ATP production pathways in the cell, i.e. oxidative phosphorylation (SIRT3) and glycolysis (HIF-1α), affects the population composition of lymphocytes and is therefore important for assessing the immune response.

Utilizing Microelectrodes to Understand Indirect Redox Targeting Reactions for High Energy Density Flow Batteries

One of the major problems with widespread implementation of renewable energy is the lack of cost-effective long-duration grid-scale energy storage filling in for the intermittent nature of solar and wind energy. Redox flow batteries (RFBs) are considered a promising solution to this problem due to their decoupled energy and power capabilities, allowing them to be scaled up for long-duration more efficiently and cost-effectively than other electrochemical energy storage devices [1]. The energy capacity of RFBs is primarily determined by the quantity of active species in the electrolyte, which is a product of the volume and the concentration. Thus, the limiting factor for energy density in RFBs is typically the solubility of the active species [2]. One probable path to enhancing the energy density without increasing the concentration is by utilizing the concept of indirect redox targeting reactions [3]. These redox-targeting flow batteries (RTFB) use solid charge storage materials in the electrolyte tanks to boost capacity, allowing the active species to act as mediators which transfer their charge by reversibly reducing or oxidizing the solid material [4].In this study, cobalt hexacyanoferrate (CoHCF) was used as a solid capacity booster in an electrolyte containing vanadium(iv/v)bis-hydroxyiminodiacetate (VBH) as mediators in acetonitrile. Constant current cycling was performed in a symmetric cell configuration with vanadium ions shuttling between vanadium(iv) and vanadium(v) oxidation states. To monitor the concentration of redox active species accurately and in real-time, a carbon fiber ultramicroelectrode (UME) was installed on the capacity limiting half-cell. This in-line UME set-up provides a better understanding of how CoHCF interacts with mediators and insights on active species crossover between half-cells. In addition, this study aims to examine the kinetics of the indirect redox-targeting reactions. As a rarely studied charge transfer process, very few studies have been reported on the kinetics of indirect redox targeting reactions [5]. Scanning electrochemical microscopy is used to understand how counter cations affect the kinetics of the reaction between the solid booster material and the mediator. Various counter cations (e.g., Ca2+, Na+, Li+) are used with the previously mentioned VBH-based mediators in order to determine the effective rate constants (keff) as well as the reversibility of the charge transfer reactions.

Parametric Modelling of a Non-Aqueous Redox Flow Battery with Solid Booster Materials

With an increasing use of renewable energy resources, such as wind and solar, one of the major challenges that need to be addressed is the energy reliability associated with the intermittent nature of these resources. Redox flow batteries (RFBs), which are considered as a promising large-scale energy storage technology, have the potential to address this issue due to their enhanced capacity retention, ease of scalability, and cost-effectiveness in long-duration energy storage [1]. Despite the promise, the widespread implementation of RFBs is currently hindered by their lower energy density compared to lithium-ion batteries and hydrogen energy storage [2].Non-aqueous redox flow batteries (NRFBs) offer volumetric energy density improvement by increasing the electrochemical potential window. While the idea of non-aqueous systems is not new in concept, they have become more prevalent and very few models have been described in literature [3]. In this study, a mathematical model of a NRFB using a bio-inspired active material, vanadium(iv/v) bis-hydroxyiminodiacetate (VBH) [4] is developed. To further increase the energy density of the system, a solid capacity booster material, cobalt hexacyanoferrate, is introduced into the electrolyte tanks. The solid booster increases the electrolyte capacity by chemically reacting with the redox active material in the tank [5]. Since the inclusion of solid booster materials is a relatively novel concept for RFBs, few resources are available, and to the best of our knowledge, no model has yet to be presented for a solid booster system [6].The mathematical model is developed with charge and species conservation using the Nernst-Planck equation. Then, the model is validated with an experimental charge/discharge curve without solid booster material. The solid booster concept is included by incorporating the shrinking core model and Gibbs free energy [7]. Using the model developed, sensitivity and correlation analyses are conducted to identify independent parameters associated with the solid booster material. Lastly, the charge/discharge experimental data with the solid booster material is fitted to the model prediction to identify the thermodynamic and kinetic parameters of the indirect chemical reaction that occurs in the tanks. The development of this model can provide insights for future studies utilizing solid boosters in redox flow batteries and help identify key parameters affecting the performance of these systems.