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We report the synthesis of nitrogen-doped graphene oxide, with 5.7-7.0 wt % nitrogen doping, from different sizes of precursor graphite and study its effect on the oxygen evolution reaction (OER) activity of IrO

One of the fundamental mechanisms developed by the host to contain the highly infectious and rapidly proliferating SARS coronavirus is elevation of body temperature, a natural fallout of which is Heat Shock Protein (HSP) over-expression. Here, for the first time, we demonstrate that the SARS-CoV-2 virus exploits the host Hsp70 chaperone for its entry and propagation and blocking it can combat the infection. SARS-CoV-2 infection as well as febrile temperature enhanced Hsp70 overexpression in host Vero E6 cells. In turn, Hsp70 overexpression elevated the host cell autophagic response that is a prerequisite for viral propagation. Suppressive and prophylactic treatment of Vero E6 cells with HSP70 inhibitor PES-Cl, a small molecule derivative of Pifithrin μ, abrogated viral infection more potently than the currently used drug Remdesivir by suppressing host HSP70 and autophagic response. In conclusion, our study not only provides a fundamental insight into the role of host Hsp70 in SARS-CoV-2 pathogenesis, it paves the way for the development of potent and irresistible anti-viral therapeutics.

BackgroundDuring the intra-erythrocytic proliferation ofPlasmodium falciparum, the host erythrocyte invasion is regarded as a complex and tightly regulated process comprising multiple receptor-ligand interactions, and numerous secretory molecules. Proteins secreted sequentially from apical organelles of merozoites serve as adhesins that play a crucial role in RBC invasion and can serve as vaccine and therapeutic targets.MethodsPurified merozoites were triggered to discharge apical organelle contents by exposure to ionic conditions mimicking that of blood plasma. The secreted proteins were subjected to tandem mass spectrometry, and a well-characterized invasion ligand, RhopH3, was identified. A novel RhopH3 receptor, 14-3-3□ was unearthed using a Bacterial two-hybrid approach. This interaction was confirmed using multiple biophysical and biochemical approaches. We were successful in disrupting this interaction using a de novo peptide binder of 14-3-3□, and we subsequently assessed its effect on merozoite invasion.ResultsA total of 66 proteins were identified in the secretory fraction with apical organellar or merozoite membrane localization. The well-known adhesin, RhopH3 was also identified and its interaction with the host phosphopeptide-binding protein, 14-3-3□ was established. We also discovered a de novo peptide with the potency to disrupt this crucial interaction, thereby blocking merozoite invasion.ConclusionWe, for the first time, report the secretory repertoire of plasmodium merozoite. Our study shows the importance of the erythrocyte protein, 14-3-3□ during the invasion process and paves the way for developing anti-malarial peptides or small molecules that inhibit the host-pathogen interaction, hence abrogating the invasion process.

The emergence of Plasmodium falciparum resistance raises an urgent need to find new antimalarial drugs. Here, we report the rational repurposing of the anti-hepatitis C virus drug, alisporivir, a nonimmunosuppressive analog of cyclosporin A, against artemisinin-resistant strains of P. falciparum. In silico docking studies and molecular dynamic simulation predicted strong interaction of alisporivir with PfCyclophilin 19B, confirmed through biophysical assays with a K(d) value of 354.3 nM. Alisporivir showed potent antimalarial activity against chloroquine-resistant (PfRKL-9 with resistance index [Ri] 2.14 ± 0.23) and artemisinin-resistant (PfKelch13(R539T) with Ri 1.15 ± 0.04) parasites. The Ri is defined as the ratio between the IC(50) values of the resistant line to that of the sensitive line. To further investigate the mechanism involved, we analyzed the expression level of PfCyclophilin 19B in artemisinin-resistant P. falciparum (PfKelch13(R539T)). Semiquantitative real-time transcript, Western blot, and immunofluorescence analyses confirmed the overexpression of PfCyclophilin 19B in PfKelch13(R539T). A 50% inhibitory concentration in the nanomolar range, together with the targeting of PfCyclophilin 19B, suggests that alisporivir can be used in combination with artemisinin. Since artemisinin resistance slows the clearance of ring-stage parasites, we performed a ring survival assay on artemisinin-resistant strain PfKelch13(R539T) and found significant decrease in parasite survival with alisporivir. Alisporivir was found to act synergistically with dihydroartemisinin and increase its efficacy. Furthermore, alisporivir exhibited antimalarial activity in vivo. Altogether, with the rational target-based Repurposing of alisporivir against malaria, our results support the hypothesis that targeting resistance mechanisms is a viable approach toward dealing with drug-resistant parasite.

Urban lakes in developing economies face tremendous anthropogenic pressure which tends to modify their role in the regional carbon cycle. This makes it imperative to quantify their carbon budget and identify the underlying factors and processes. Present study aims to understand the seasonal carbon dioxide (CO2) dynamics of an urban lake in a semi-arid subtropical region and identify major controls operating on it. Systematic sampling of Bhalswa lake waters was undertaken in winter and summer of 2017–2018. The hydrochemical data generated were used to determine partial pressure and evasion flux of CO2 using pH and total alkalinity couple. The lake waters show CO2 supersaturation with respect to atmospheric equilibrium and act as a source of CO2 to the atmosphere in both seasons. The average partial pressure of carbon dioxide (pCO2) and CO2 evasion flux observed is 1033.73 ± 229.07 µatm and 6.33 ± 2.23 mmol m−2 d−1, and 1034.99 ± 187.37 µatm and 11.65 ± 3.42 mmol m−2 d−1 during winter and summer, respectively. Neither pCO2 nor CO2 evasion flux shows any significant seasonal difference. For yearly dynamics, dissolved organic carbon, dissolved inorganic carbon and dissolved oxygen act as strong controls on lake water pCO2. While for individual seasons, pH and water temperature act as significant controls. Among various pollution sources, untreated sewage and dairy waste, seepage of polluted groundwater and atmospheric dust impact the lake's carbon dynamics. The present study will help better understand the role of freshwater wetlands of ever-expanding urban areas in the regional carbon cycle of developing economies.

In this study, in situ electrochemical Raman spectroscopy was applied to clarify the charge storage mechanism in three types of anodes, synthetic graphite, reduced graphene oxide (rGO), and nitrogen-doped reduced graphene oxide (N-rGO). The Li+ intercalation phenomenon was measured in LiPF6 electrolyte solution using a modified coin cell setup. The synthetic graphite anode showed the splitting of the G peak at the potential E < 0.2 V vs. Li/Li+, corresponding to the formation of a graphite intercalation compound (GIC) and its second-order 2D peak was found to be red-shifted due to charge transfer and induced strain in the potential region of 0.5 to 0.15 V vs. Li/Li+. In the case of rGO, the lattice defects assisted in large and early intercalation of electrolyte ions, which is confirmed by the red-shift in the G peak (∼36 cm−1) and its early disappearance below 0.3 V vs. Li/Li+, respectively. Unlike rGO, nitrogen vacancies in N-rGO provide active sites for Li+ intercalation, resulting in enhanced charge transfer, displayed by the large red-shift in the G peak (∼55 cm−1) and blue-shift in the D peak. In addition, a new Raman peak at 1850 cm−1 was observed in N-rGO for the first time, corresponding to the formation of a reversible intermediate species from the interaction between Li+ and nitrogen vacancies. This work demonstrates the use of a simple in situ technique to get insight into the nano-carbon electrodes during device operation and to reveal the role of doped nitrogen atoms for Li+ intercalation.

The current research deals with the study of boron and nitrogen co-doped reduced graphene oxide (BN-rGO) as a support material for iridium oxide (IrO2) nanoparticles for oxygen evolution reaction (OER) catalysis. The synthetic approach for the IrO2–BN-rGO catalyst involves the combination of pyrolysis and hydrothermal methods used for hierarchical nanostructures. BN-rGO possesses B–N, B–C, and N–C functional groups to support and stabilize the IrO2 catalyst nanoparticles. The altered electronic states of IrO2 on the BN-rGO support are compared with those of IrO2 on a non-doped support, rGO (IrO2–rGO), and on commercial BN sheets (IrO2–c-BN). The catalyst shows a low overpotential (300 mV at 10 mA cm−2), high current density (55 mA cm−2 at 1.65 V), and significantly high durability (12 350 cycles; 45 h) in an acidic environment. The high stability of IrO2–BN-rGO may result from the presence of a chemically and electrochemically stable B–N bond. We confirm that other functional groups (B–C and N–C) and the rGO framework are equally crucial for better attachment of IrO2 nanoparticles.

In recent times, non-conventional farming practices have emerged as a viable alternative to check soil degradation due to the indiscriminate application of agrochemicals. However, limited studies h...

The present work details the development of IrO2 nanoparticles (nps) supported on B-doped reduced graphene oxide as an oxygen evolution reaction (OER) electrocatalyst for electrochemical water splitting. IrO2 on boron-doped reduced graphene oxide (B-rGO) is synthesized via sequential steps of pyrolysis to prepare B-rGO and a hydrothermal method for modification of B-rGO with IrO2 nps. With 2 wt% boron doping in graphene, a 0.10 V decrease in the OER onset potential is observed for IrO2 catalysts on B-rGO (IrO2-B-rGO). The Tafel slope for the OER on B-rGO is estimated to be 124.8 mV dec−1, which is lower than that on IrO2-rGO and suggests strong adsorption of intermediates such as OH on the IrO2 surface by the B-doping of graphene in acidic solution. In this article, we demonstrate the effect of boron doping on the electronic structure modification of the IrO2 nps, which is expected to generate more electrocatalytic centers and enhance the catalytic activity.

Surface water samples (n = 55) from four wetlands (Lost-W1, Sultanpur-W2, Damdama-W3, and Basai-W4) of Gurugram were studied for their hydrogeochemical characterization, quality assessment and suitability for various purposes. The parameters studied were temperature, pH, electrical conductivity (EC), total dissolved solids (TDS), dissolved oxygen (DO), chemical oxygen demand (COD), biological oxygen demand (BOD), dissolved organic carbon (DOC), major cations, major anions, and trace metals. The results indicate that water samples of all the four wetlands are alkaline. Among studied parameters, pH (8.9), TDS (2233 mg/l), alkalinity (428 mg/l), PO43− (7.05 mg/l), F− (1.88 mg/l), Na+ (597 mg/l), and K+ (32 mg/l) are above permissible limits (PL). BOD and COD are above WHO limits in all the wetlands, except W1. Among ions, HCO3− and Ca2+ are dominant in W1, W2, and W3 which indicate weathering of Ca2+ and HCO3− minerals (carbonate weathering), whereas Cl− and Na+ are dominant in W4, which indicate strong anthropogenic influence. Lower values of the majority of ions in winter as compared to summer indicate the dilution effect. Among metals, Fe (549 mg/l), Cr (90 mg/l), and Ni (117 mg/l) are above PL. Piper diagram revealed the Ca-HCO3 type of water in W1, W2, and W3 and Na-Cl type in W4. Gibbs plot indicated rock-forming minerals are dominantly affecting the water chemistry of all the wetlands. WQI suggested unsuitability of water from W4 (in both seasons) and W3 (in summer) for drinking, as well as irrigational indices (Wilcox, USSL plots, PI, RSC, KI, and MH) suggest unsuitability of W4 water for irrigation. Also, water from W4 is not suitable for cattle drinking. Water from W1, W2, and W3 is suitable for human consumption, irrigation, and cattle drinking except W3 water in summer which is not suitable for human consumption. Hence, it is concluded that, among studied wetlands, W4 is maximally perturbed, whereas W2 and W3 are disturbed to a lesser extent. All these wetlands need continuous monitoring and timely measures.

Graphene and heteroatom-doped graphene are potential candidates for high-performance energy storage applications, such as supercapacitors. Herein, we have studied the structure and defect generation in nitrogen-doped reduced graphene oxide (N-rGO), synthesized via pyrolysis of urea in a wide temperature range (600–900 °C). Nitrogen-doped defect densities were analyzed in detail by the deconvolution of the Raman spectrum, where we found the importance of additional I and D’’ peaks. I peak is found to be sensitive to the dopant, and D” peak is consistent with the crystallinity, which are further revealed by X-ray photoelectron spectroscopy and X-ray diffraction measurements. Synthesized N-rGO was then investigated for the supercapacitor electrode. N-rGO synthesized at 800 °C, having low crystallinity (crystallite size 3.44 nm), highest degree of reduction (C/O ratio = 23), high specific surface area (152.3 m2 g−1), and presence of both pseudocapacitive and electric double layer behavior, resulting in highest areal capacitance of 138.4 mF cm−2, lowest self-discharge rate, and exceptional capacity retention of 121.7% after 10,000 cycles of charge–discharge. The synthesized electrode material has also been tested for a symmetric supercapacitor cell showing high specific capacitance 66.8 F g−1 in 0.5 M H2SO4 electrolyte. This study is a first of its kind of structural evaluation and Raman characterization of N-rGO for application in supercapacitor cell.

Surface soil samples (n = 36) from different land use areas (rural, industrial, commercial and residential) of Gurugram were studied for physicochemical properties and trace metal (Cu, Cr, Co, Ni, Pb, and Zn) abundances to identify their sources and spatial distribution over the region. Based on the results obtained, the soils of Gurugram, in general, are sandy (75–85 wt%), alkaline, and unpolluted with moderate pollution at certain sites. The average pH lies near 7.5 in all the land uses. Electrical conductivity in residential (329 μS/cm) soils is almost thrice the value in rural (87 μS/cm) soils. The primary metal of concern is Zn, which is above the permissible limits, followed by Cu and Pb. Common alumino-silicate minerals observed in the soils are quartz, K-feldspar, muscovite and sodic plagioclases. Based on the calculated average geo-accumulation index (Igeo) values of samples, soils of Gurugram, in general, are uncontaminated and have values

Platinum nanoparticles (NPs) modified with alkylamines containing various aromatic rings (benzyl, naphtyl, anthryl, and pyrenyl) were synthesized as model cathode catalysts for fuel cells to investigate the role of aromatic surface modification agents on catalytic performance. Surface modification of Pt was confirmed by nuclear magnetic resonance spectra for NPs and thermogravimetric analysis for carbon-supported catalysts. Surface modification of Pt NPs with aromatic alkylamines improved the electrocatalytic activities for the oxygen reduction reaction, whose activity values increased by increasing the number of aromatic rings. The effect of surface modification on the electronic properties of the catalyst was evaluated by X-ray photoelectron spectroscopy. A large positive shift in the Pt 4f binding energy of surface-modified catalyst, especially for anthryl and pyrenyl modifications, was observed, indicating that one of the important factors is metal–support interaction facilitated by the aromatic groups through the π–π interactions with carbon support.

Modification of electrode surface using borylated-thiophene monomer resulted in the formation of a pre-formed solid electrolyte interface (SEI). The obtained ready-to use anodes did not show any loss in capacity during the first few cycles of charging and discharging. Herein, we report the synthesis and utilization of boron containing monomer to form an artificial SEI to reduce the interfacial resistance at SEI. Electropolymerization was performed via two methods, i) pre-modification and ii) in-situ modification. After the modification of the anodes, modified electrodes showed increased capacities, reduced capacity fading effect, and reduced interfacial resistance. Charge-discharge characteristics of half-cell with borylated thiophene polymer over graphite was studied and compared with graphite without any modification and polythiophene coated graphite.

Delhi, India’s capital is the second largest urban agglomeration in the world. It is expected to surpass Tokyo to become world’s largest city by 2028 with ~37 million inhabitants (UNDESA, 2018). This rapid growth is characterized by unsystematic urbanization, rapid shifts in its landuse patterns and tremendous pressure on the city’s natural resources. Among other forms of resource degradation, rapidly shrinking and stinking wetlands are of primary concern. Thus evidence-based policy making for their sustainable development and conservation require regular reporting and monitoring of their status.Present study compares the hydrochemistry of two urban wetlands of Delhi (Sanjay lake and Bhalswa lake) having some crucial differences in their nature and catchment area activities. Surface water quality of these wetlands was studied for winter and summer with respect to their physico-chemical properties (temperature, pH, dissolved oxygen, electrical conductivity, total dissolved solids, alkalinity and hardness) including major ions and trace metals employing standard analytical methods (APHA, 2005). Waters from both the wetlands are alkaline in nature. While pH of Sanjay lake shows a greater variation (7.9 to 10.8), that of Bhalswa lake is fairly constant (8.4 to 8.7), across the seasons. The wetland waters also vary seasonally in their chemistry. Differences in the nature and associated landuse of the wetlands is reflected in their water quality. Hydrogeochemistry of these wetlands were determined by Piper plot and Gibb’s diagram. While water from both the wetlands are Na+- SO42- type during summer, water from Bhalswa lake is Na+- SO42- type and that from Sanjay lake is Ca2+-Mg2+- SO42- type during winter. While water from Bhalswa lake shows an evaporation dominance regime, that from Sanjay lake show dominance of rock-water interaction. Water from both the wetlands are generally unsuitable for drinking purpose. While water from Bhalswa lake is unsuitable for irrigation as well, water from Sanjay lake is generally suitable as determined using various indices (% Na, Residual Sodium Carbonate, Sodium Absorption Ratio, etc.). Both the drinking and irrigational water quality of these wetlands deteriorate during summer. Factor analysis was also used to determine sources of pollution for the two wetlands during both winter and summer. Domestic sewage is observed to be a major source of pollution for both the wetlands. Thus, this study indicates that urban wetlands of Delhi are fast depleting in their health. In light of their importance as a significant urban water resource, a crucial ecological niche and an essential recreational spot for urban areas, there is an urgent need for positive interventions.

Conduction mechanisms in solid polymer electrolytes of Li ion batteries have always been a concern due to their theoretical limitation in conductivity value. In an attempt to increase the ionic conductivity of solid state electrolytes, used in lithium ion secondary batteries (LiBs), we studied the synthesis and conductive properties of a low molecular weight cyclic organoboron crystalline electrolyte. This electrolyte was expected to show better electrochemical properties than solid polymer electrolytes. The electrolyte was doped with LiTFSI salt via two different methods viz. (1) facile grinding of the crystalline sample with lithium salt under a nitrogen atmosphere and (2) a conventional method of solvent dissolution and evaporation under vacuum. The electrochemical properties were studied under specific composition of Li salt. The presence of crystallinity in the electrolyte can be considered as an important factor behind the high ionic conductivity of an all solid electrolyte of this type. Charge–discharge properties of the cell using the electrolyte were investigated in anodic half-cell configuration.

Environmental issues of global warming and depletion of fossil fuels have become significant topics in recent years. Effective utilization of renewable energies such as solar and wind energy is a critical issue to overcome the environmental problems. A large amount of effort has been invested in researches for conversion and storage of surplus energies. One of the prospective candidates is production of hydrogen via water electrolysis in polymer electrolyte water electrolyzer. However, catalytic activity, durability, and cost of water electrolysis systems are inadequate for practical application due to low kinetics and high over-potential of electrode reactions, especially, oxygen evolution reaction (OER) on the anode [1,2]. As OER catalyst, iridium oxide (IrO2) particles have been employed because of its high activity and durability. However, high cost and low abundance of iridium require reduction of iridium loading amount on the catalyst. Recently, we have succeeded to synthesize novel IrO2 nanoparticle with large surface area of IrO2 catalyst, which are supported on carbon nanotubes [3] and heteroatom-doped graphene [4], to improve OER activity. For further improvement of OER activity, we also develop alloy catalyst of IrO2 with other metals, such as ruthenium oxide (RuO2) to enhance the specific activity of the catalyst for OER. In this study, we have synthesized novel alloy nanoparticle catalysts, IrRuOx, supported on the heteroatom (N or B) doped reduced graphene oxide (rGO), IrRuOx/N-rGO and IrRuOx/B-rGO, and evaluated its catalytic activity as active catalysts for OER. The IrRuOx/N-rGO and IrRuOx/B-rGO catalyst were synthesized by hydrothermal method. Briefly, nitrogen- or boron-doped reduced graphene oxide (N-rGO, B-rGO) were prepared by thermal treatment of mixture of urea or boric anhydride and graphene oxide (GO), which was prepared by modified Hummers’ method, at 800 and 1000˚C, respectively, for 60 min. Then, required amounts of metal complexes, H2IrCl6 and RuCl3, and N-rGO, or B-rGO were dispersed in ethanol/water mixture and heated at 80˚C for 6 h. Finally, the mixture was heated at 150˚C in hydrothermal autoclave for 4 h to form IrRuOx nanoparticles. The synthesized catalysts were characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and electrochemical methods. The OER activity of the catalysts was examined in 0.5 M H2SO4 solution by linear sweep voltammetry (LSV) using a rotating disk electrode (RDE) system. A TEM image of the IrRuOx/N- rGO catalyst is shown in Figure 1. The IrRuOx nanoparticles were dispersed uniformly on the surface of N-rGO substrate. An average size of the nanoparticles was ca. 1.7 nm. The loading amount of the IrRuOx catalyst is estimated to be approximately 20.1 wt% by EDX measurements. In the case of IrRuOx/B- rGO, average particle size was also ca. 1.7 nm, and the loading amount of the catalyst is 11.7 wt%. In addition, the EDX analysis reveals that the ratio of Ir to Ru of the IrRuOx nanoparticles is proportional to the molecular ratio of starting material compounds, H2IrCl6 to RuCl3. We confirmed the composition of the catalysts by XPS, as shown in Figure 2, and the results consisted with EDX measurement. Furthermore, the XPS results reveal that binding energy of Ir 4f peak on both catalysts was shifted to 0.1 eV lower energy state than that on the catalyst without alloying. The shift of the binding energy of Ir 4f peak reflects the modification of the electronic state of Ir, which affects adsorption energy of O and the catalytic activity for OER. Figure 3 shows mass activity of the prepared catalysts for OER estimated from LSV in 0.5 M H2SO4 solution. Electrochemical measurement reveals that the mass activity of the IrRuOx catalyst is higher than that on the catalyst without alloying. In addition, the catalyst supported on B-rGO has higher activity than the catalyst on non-doped or N-doped GO supports. High activity of the IrRuOx / B-rGO catalyst indicates that alloying IrO2 with RuO2 and heteroatom doping on the support materials improve the catalytic activity for OER. In summary, we successfully prepared the alloy catalysts of IrO2 and RuO2 supported on N-rGO and B-rGO substrate, and the catalysts can be promising candidates as anodes for water electrolysis. References [1] M. Carmo, D. L. Fritz, J. Mergel, D. Stolten, Int. J. Hydrogen Energy 38 (2013) 4901. [2] J. Cheng, H. Zhang, H. Ma, H. Zhong, Y. Zou, Electrochim. Acta 55 (2010) 1855. [3] R. Badam, M. Hara, H.-H. Huang, M. Yoshimura, Int. J. Hydrogen. Energy, 43 (2018) 18095. [4] M. Hara, R. Badam, G. J. Wang, H.-H. Huang, M. Yoshimura, ECS Trans., 85 (2018) 27. Figure 1

Organically (octyl amine, OA) surface modified electrocatalyst (OA-Pt/CB) was studied for its oxygen reduction reaction (ORR) activity via dc methods and its charge and mass transfer properties were studied via electrochemical impedance spectroscopy (EIS). Comparison with a commercial catalyst (TEC10V30E) with similar Pt content was also carried out. In EIS, both the catalysts showed a single time-constant with an emerging high-frequency semicircle of very small diameter which was fitted using suitable equivalent circuits. The organically modified catalyst showed lower charge-transfer resistance and hence, low polarization resistance in high potential region as compared to the commercial catalyst. The dominance of kinetic processes was observed at 0.925-1.000 V, whereas domination of diffusion based processes was observed at lower potential region for the organic catalyst. No effect due to the presence of carbon was observed in the EIS spectra. Using the hydrodynamic method, higher current penetration depth was obtained for the organically modified catalyst at 1600 rpm. Exchange current density and Tafel slopes for both the electrocatalysts were calculated from the polarization resistance obtained from EIS which was in correlation with the results obtained from dc methods.

The present study had been conducted to study the shelf life of grapes with coatings of Aloe Vera suspended in water with concentrations of 0, 10, 20 and 30 per cent Aloe veraand was stored in poly packaging and open plates under different temperatures of 0⁰C and 30⁰C in refrigerator and incubator. The data was compared with the original shelf life of grapes to determine the efficiency of the Aloe Vera coating. Aloe Vera based coatings provided good gloss and 20 per cent coating concentration gave the best visual and physicochemical results. It was found that 20 per cent coating concentration of Aloe Vera is the most effective and appropriate for the extension of shelf life of grapes.It was also found that the use of low temperature storage in combination with edible coating and packaging extends marketability by reducing moisture loss.In short, the shelf life of grapes can be increased by using Aloe Vera gel coating and the spoilage due to fungal infection of grapes can be reduced.

Advances in lithium-ion battery electrolyte materials have created a niche for the evolution of various electrochemical techniques. Appropriate diagnostic techniques to evaluate new electrolytes are of paramount importance, as the conventional techniques lead to prejudiced conclusions. Organic–inorganic hybrid ion gels, employed as electrolytes for the carbon anodic half-cell, showing discrepancies in its charge discharge profile, were probed for their abnormal charge–discharge behaviour. Dynamic electrochemical impedance spectroscopy (DEIS) was used as a diagnostic tool; inferences were drawn from chargetransfer resistance values and used as indicators to delimit the potential boundaries for optimum performance of the cells. Identifying the cut-off potentials through DEIS and subsequent charge–discharge provided clean profiles.

We report the synthesis of a crystalline cyclic organoboron compound that shows an anomalous Li-ion conduction behaviour with specific composition and method of insertion of a Li salt. The enhanced ionic conductivity of crystalline boric ester/LiTFSI prepared by the grinding method should be due to the formation of regulated ion-conduction channels scaffolded by boron-anion interaction.

Recently, environmental issues such as global warming and depletion of fossil fuels have become important topic, and progress toward sustainable societies with renewable energies such as solar and wind energy is a critical issue to overcome the social problems. Conversion of surplus energies to hydrogen via water electrolysis has attracted attention as energy storage method to utilize renewable energies effectively. However, activity, durability, and cost of catalysts are insufficient for practical application in water electrolysis systems due to high over-potential and low kinetics of electrode reactions, especially, oxygen evolution reaction (OER) on the anode [1-2] for polymer electrolyte water electrolyzer (PEWE). Iridium oxide (IrO2) particles have been used as anode catalysts, because of its high activity and durability for OER. However, decreasing iridium loading amount is required to reduce catalyst cost. In a previous study, we have successfully synthesized novel IrO2 nanoparticle catalyst supported on carbon nanotubes with large surface area of IrO2 catalyst to improved OER activity [3]. For further improvement of OER activity, increasing the specific activity of the catalyst for OER is required. One of the approaches to improve catalytic activity is formation of alloy of iridium with other metals with high activity, such as ruthenium. In the present study, we have synthesized novel alloy nanoparticle catalysts, IrRuOx, supported on the reduced graphene oxide (rGO), as active catalysts for OER. The IrRuOx / rGO catalyst was characterized and evaluated in catalytic activity for OER in sulfuric acid solution. The IrRuOx / rGO catalyst was synthesized by hydrothermal method. Briefly, required amount of metal complexes, H2IrCl6 and RuCl3, and graphene oxide (GO) prepared by modified Hummers’ method were dispersed in ethanol/water mixture and the mixture was heated at 80˚C for 6 h. Then, the mixture was heated at 150˚C in hydrothermal autoclave for 4 h to form IrRuOx nanoparticles. The IrRuOx / rGO catalysts were characterized by transmission electron microscopy (TEM), energy dispersed X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and electrochemical methods. The OER activity of the IrRuOx / rGO was examined in 0.5 M H2SO4 solution by linear sweep voltammetry (LSV) using a rotating disk electrode (RDE) system. A TEM image of the Ir0.7Ru0.3Ox / rGO catalyst is shown in Figure 1. The Ir0.7Ru0.3Ox nanoparticles with wide particle size distribution were dispersed on the surface of rGO substrate. An average size of the nanoparticles was 1.9 ± 0.8 nm. The loading amount of the Ir0.7Ru0.3Ox catalyst is estimated to be approximately 23.9 wt% by EDX measurements. In addition, the EDX analysis reveals that the ratio of Ir to Ru of the IrRuOx nanoparticles is proportional to the ratio of starting materials, H2IrCl6 and RuCl3. The XRD patterns of the IrRuOx / rGO catalysts with different Ir/Ru ratio are shown in Figure 2. The XRD data shows the (200) peak of IrRuOx is shifted to small angle and became broader with increasing Ir ratio of the catalysts. Furthermore, the XPS results of the IrRuOx / rGO catalysts showed binding energy of Ir 4f peak was shifted to a lower energy state with increasing the ratio of Ru. The XRD and XPS data suggest that nanoparticles of the catalyst form alloy of RuO2 and IrO2. In addition, the shift of the binding energy of Ir 4f peak reflects the modification of the electronic state of Ir, which affects the catalytic activity for OER, by alloy formation with Ru atom. Figure 3 shows linear sweep voltammogram of the IrRuOx / rGO catalyst obtained in 0.5 M H2SO4 solution. Electrochemical measurement reveals activity of the IrRuOx / rGO catalyst for OER is higher than that of the IrO2 / rGO catalyst, especially, onset potential of the reaction is 68 mV lower than that on the IrO2 / rGO catalyst. High activity of the IrRuOx / rGO catalyst indicates that alloying IrO2 with RuO2 improves the catalytic activity for OER. In summary, we successfully prepared the alloy catalysts of IrO2 and RuO2 supported on rGO substrate, and the IrRuOx / rGO catalysts can be a promising candidate as anode for water electrolysis. Acknowledgements This work was supported by JSPS KAKENHI Grant number 17K05969. References [1] M. Carmo, D. L. Fritz, J. Mergel, D. Stolten, Int. J. Hydrogen Energy 38 (2013) 4901. [2] J. Cheng, H. Zhang, H. Ma, H. Zhong, Y. Zou, Electrochim. Acta 55 (2010) 1855. [3] R. Badam, M. Hara, H.-H. Huang, M. Yoshimura, Int. J. Hydrogen. Energy, 43 (2018) 18095. Figure 1

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The effect of actinomycin D on chick embryos cultivated in vitro by New’s culturing method was studied. Exposure of chick embryos to actinomycin D (0.05 µg/ml) at the primitive streak stage (stage 4; Hamburger and Hamilton) for 6 h showed interference in orotic acid formation. The assay of the enzyme dihydroorotic acid dehydrogenase was carried out in both treated and control embryos. No enzymic activity was observed in actinomycin-D-treated embryos in contrast to the considerable activity in the controls. These observations suggest an interference by actinomycin D in the biogenesis of the enzyme dihydroorotic acid dehydrogenase.