COVID-19 is caused by the SARS-CoV-2 that belongs to the beta-coronaviruses subfamily.Coronaviruses, a genus of the Coronaviridae family, are enveloped viruses with a large plus-strand ribonucleic acid (RNA) genome (Fehr et al., 2015).The genomic RNA is 27-32 kb in size, capped, and polyadenylated.Coronaviruses were identified in several non-human species, including rats, mice, chickens, cattle, turkeys, swine, cats, dogs, rabbits, and horses.In these species, coronavirus infection often causes devastating epizootics of respiratory or enteric diseases.Several coronaviruses, such as HCoV-229E and HCoV-OC43, were identified since the mid-1960s.Before the SARS-CoV outbreak, coronaviruses were only thought to cause mild, self-limiting respiratory infections in humans, commonly referred at as "colds."These viruses are endemic among the human populations, causing 15-30% of respiratory tract infections each year.Rarely, these viruses can cause lower respiratory tract infections, especially in neonates, in the elderly, and in individuals with underlying illnesses.SARS-CoV, a novel coronavirus, was identified in 2002 as the pathogenic agent of the SARS outbreak that occurred in ABSTRACTSevere acute respiratory syndrome coronavirus 2 (SARS-Cov-2) is the pathogen that causes coronavirus disease 2019 (COVID-19).As of October 31, 2020, the outbreak of COVID-19 has caused 1,201,902 deaths around the world including 122,000 in India.The current evidence showed that severely ill patients tend to have a high concentration of pro-inflammatory cytokines, such as interleukin (IL)-6, compared to those who are moderately ill.Besides, excessive infiltration of pro-inflammatory cells, mainly involving macrophages and T-helper 17 cells, has been found in lung tissues of patients with COVID-19 by postmortem examination.Recently, increasing studies indicate that the "cytokine storm" may contribute to the mortality of COVID-19.This review focuses on the cytokine storm (CS) in the context of infection, with particular emphasis on respiratory viruses and shows that SARS-Cov-2 selectively induces a high level of IL-6 and results in the exhaustion of lymphocytes.It is also highlighted how high-throughput genomic methods are revealing new insights into the CS.Finally, how current evidence indicates that Tocilizumab, an IL-6 inhibitor, is relatively effective and safe, besides corticosteroids, programmed cell death protein (PD)-1/PD-L1 checkpoint inhibition, cytokine-adsorption devices, intravenous immunoglobulin, and antimalarial agents could be potentially useful are also discussed.

Chromate, the invisible danger of environment is found to be degrading both animal and plant kingdom with its carcinogenic oxidizing ability by contaminating ground water. To prevent uncontrolled Cr(VI) contamination, various chemical methods for reduction of hazardous Cr(VI) to less toxic Cr(III) have been established of which aqueous reduction, ion exchange, liquid-liquid extraction, and electrocoagulation are found to be effective. Bioremediation, a greener approach is always of greater interest. The aim of the present study is to utilize mango leaves for the reduction of hexavalent chromium and to accelerate the reduction process by the use of surfactants. A 168 h study reveals that in absence of surfactants 58% of the total chromium(VI) is reduced, whereas removal percentage increases upto 75% in the presence of neutral surfactant TX-100 and upto 79% in the presence of anionic surfactant SDS.

Abstract The kinetic study of catalytic oxidation of D-lyxose by hexavalent chromium has been investigated spectrophotometrically under pseudo first order condition at temperature 313 K. The rate of oxidation of D-lyxose is very slow. Picolinic acid (PA), 2,2′-bipyridine (bpy), 1,10-phenanthroline (phen) are used as promoter to accelerate the rate of the reaction. Phen acts as the most effective promoter in aqueous medium. The rate of the reaction is also increased in presence of nonionic surfactant Triton-X-100 (TX-100) and anionic surfactant sodium dodecyl sulphate (SDS). They are used as catalyst in this reaction. Thus the observed micellar effects have been explained by considering the hydrophobic and electrostatic interactions between the reactants and surfactants in terms of the proposed mechanism. However, the combination of promoter and surfactants produces a better result. The maximum rate enhancement is obtained in presence of the combination of phen and TX-100.

The presence of hexavalent chromium in waste water is a serious environmental problem due to its toxicity and carcinogenicity. Bioremediation is an efficient alternative to the conventional chemical methods of treatment. Bioremediation of toxic hexavalent chromium is done by the reduction of hexavalent chromium to relatively less toxic trivalent chromium. In this study, water extract of Sajina flower, which contains different types of reducing components such as sugar, amino acid, is used as reductant and the rate of bioremediation is increased by treatment with anionic and neutral surfactants. Here surfactants are used as catalyst in the bioremediation process. Sodiumdodecyl sulfate (SDS) is found to be the best catalyst. In the absence of surfactants, 60.37% of the total chromium(VI) is reduced within 285 h, whereas the removal percentage increases up to 96.25 and 99.37% in the presence of TX-100 and SDS, respectively, in minimum time.

The micellar catalyzed 2,2′-bipyridine (bipy)-promoted oxidation of glycerol to glyceraldehyde by chromic acid is investigated under the criteria [glycerol]T ≫ [Cr(VI)]T at 30 °C. The critical micellar concentrations values of the three representative surfactants, N-cetylpyridinium chloride (CPC), sodium dodecyl sulphate (SDS), and TX-100, are determined by conductometric and spectrophotometric methods. The oxidized product glyceraldehyde is identified by 2,4-DNP test and FTIR spectral measurement. The pseudo-first-order rate constants (k obs, s−1) are calculated from the slope of plots of ln(A 450) versus time (t) which are linear. From these plots, the kinetic parameter k eff values are calculated and the k eff value of SDS-catalyzed bipy-promoted reaction path was found to be highest among all the combinations. In the bipy-promoted oxidation path, Cr(VI)–bipy complex is the main active oxidant which undergoes attack by the substrate to form the product. The active oxidant Cr(VI)–bipy complex reacts with glycerol to form a ternary complex which undergoes redox decomposition in a rate-limiting step. Here, the anionic surfactant SDS and the neutral surfactant TX-100 both catalyze the reaction in the presence of bipy, whereas the cationic surfactant CPC and neutral surfactant TX-100 inhibit the reaction in the absence of bipy. SDS is found to be the most suitable micellar catalyst for the bipy-promoted chromic acid oxidation of glycerol.

Bioremediation is an efficient and cheap process for the removal of heavy metals. Solid agricultural wastes are frequently used as biosorbent for the removal of Cr(VI). In this study, water extract of Azadiracta indica sawdust is used to reduce Cr(VI) to Cr(III) and thereby lowering the toxicity. Water extract of A. indica sawdust effectively reduces hexavalent chromium at acidic pH (pH = 2). The reaction is irreversible. Trivalent chromium produced after reduction of Cr(VI) forms soluble organo-Cr(III) complex. Coordination of Cr(III) in the water extract occurs via the chelating coordination of -OH, -NH, etc, functional groups. The presence of these functional groups were confirmed from the IR spectra of the freeze-dried water extract, and the formation of Cr(III) is proved from the UV-vis spectra of the reaction mixture after the completion of reaction. But the rate of this reduction is very slow. Addition of nonfunctional surfactants increases the rate of reduction. Anionic surfactant sodium dodecylsulphate produces maximum effect.

Kinetic data for oxidation of D-sorbitol to glucose by hexavalent chromium in aqueous medium and aqueous surfactant medium (SDS, TX-100) have been reported. Effect of promoter such as PA, bipy and phenanthroline on the reaction has been investigated. The reaction is performed under pseudo first order condition with an excess of substrate over the oxidant. The reaction is first order with respect to substrate and oxidant. The micelles have a catalytic effect on the reaction. Combination of phen and TX-100 produces almost twelve times increase in rate of oxidation.

Cr(VI) is introduced into environment as a byproduct of industries. It is highly toxic. Biosorption of hexavalent chromium by various types of sawdust appears as a very cost-effective alternative for decontamination of Cr(VI) bearing effluents. In this work water extract of siris sawdust is used for the bioremediation of hexavalent chromium. Cr(VI) ions were reduced to Cr(III) ions as a result of oxidation of organic components present in the water extract of siris sawdust. Formation of Cr(III) is proved by UV-VIS spectroscopy. Functional groups involved in the reduction of Cr(VI) are characterized by FTIR spectroscopy. Bioremediation rate is increased by the use of anionic surfactant sodium dodecylsulphate (SDS) and neutral surfactant Triton-X-100 (TX-100). Here they act as micellar catalyst. Formation of micelles which is responsible for the catalysis of the process is proved by SEM and optical images of the solution. In absence of surfactants 39% of the total chromium(VI) is reduced within 531 h whereas removal percentage increases upto 54 % in presence of TX-100. Again in presence of SDS the reduction process is almost 99 % complete within 531 h.

In aqueous acidic media, picolinic acid, 2,3-dipicolinic acid, and 2,6-dipicolinic acid promoted Cr(VI) oxidation of lactose to lactobionic acid has been carried out at room temperature. A possible reaction mechanism, which is based on the kinetic results and the product analysis, has been proposed. The anionic surfactant sodium dodecyl sulphate (SDS) and nonionic surfactant Triton-X-100 (TX-100) accelerate the process while the cationic surfactant N-cetylpyridinium chloride (CPC) retards the reaction.

The kinetics of oxidation of benzaldehyde by chromic acid in aqueous and aqueous surfactant (sodium dodecyl sulfate, SDS, alkyl phenyl polyethylene glycol, Triton X-100 and N-cetylpyridinium chloride, CPC) media have been investigated in the presence of promoter at 303 K. The pseudo-first-order rate constants (kobs) were determined from a logarithmic plot of absorbance as a function time. The rate constants were found to increase with introduction of heteroaromatic nitrogen base promoters such as Picolinic acid (PA), 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen). The product benzoic acid has been characterized by conventional melting point experiment, NMR, HRMS and FTIR spectral analysis. The mechanism of both unpromoted and promoted reaction path has been proposed for the reaction. In presence of the anionic surfactant SDS, cationic surfactant CPC and neutral surfactant TX-100 the reaction can undergo simultaneously in both aqueous and micellar phase with an enhanced rate of oxidation in the micellar phase. Both SDS and TX-100 produce normal micellar effect whereas CPC produce reverse micellar effect in the presence of benzaldehyde. The observed net enhancement of rate effects has been explained by considering the hydrophobic and electrostatic interaction between the surfactants and reactants. SDS and bipy combination is the suitable one for benzaldehyde oxidation.

Oxidation of glutamic acid is performed in aqueous acid media at 30 o C under the kinetic condition (glutamic acid)T>>(Cr(VI))T. Effect of combination of micellar catalyst (SDS, TX-100) and promoter (PA, bpy, phen) has been studied. Among the promoters phen accelerates the reaction most in aqueous media. But the rate acceleration is small in the case. Combination of promoter and catalyst produces much better result. Maximum rate enhancement occurs in presence of the combination of bpy and SDS.

Chromic acid oxidation of tartaric acid in aqueous acid media produces glycolaldehyde very sluggishly at room temperature. Suitable combination of promoter (2,2'-bipyridine and 1,10-phenanthroline) and micellar catalyst (sodium dodecyl sulphate, cetylpyridinium chloride, triton X-100) enhances the rate of reaction to almost 14-fold. Observation showed that anionic surfactant (SDS) and nonionic surfactant (TX-100) accelerates the process but cationic surfactant (CPC) retards the reaction. The efficient combination for the production of glycolaldehyde from tartaric acid is found to be 1,10-phenanthroline and SDS.

Chromic acid oxidation of dl-mandelic acid in the presence and absence of different promoters has been studied in aqueous media under the kinetic conditions [mandelic acid]T ≫ [Cr(VI)]T and [promoter]T ≫ [Cr(VI)]T at 30 °C. The promoters used in this oxidation reaction, picolinic acid (PA), 2,2′-bipyridine (bpy), and 1,10-phenanthroline (phen), are strong chelating ligands which form complexes with most transition metal ions. The reaction is first-order with regard to [H+], [mandelic acid]T, and [Cr(VI)]T and also has first-order dependence on [promoter]T. HCrO4 − was found to be kinetically active in the absence of promoters; in the presence of promoters the Cr(VI)–promoter complexes were believed to be the active oxidants. In this path the Cr(VI)-promoter complex in each case undergoes nucleophilic attack by the mandelic acid to form a ternary complex which subsequently undergoes redox decomposition involving 3e transfer as the rate-determining step. Among the three promoters oxidation is much faster with 1,10-phenanthroline.

Picolinic acid, 2,2'-bipyridine and 1,10-phenanthroline promoted Cr(VI) oxidation of o-galactose to D-galactonic acid in three representative aqueous micellar media has been studied. The anionic surfactant (SDS) accelerated the rate of reaction while the cationic surfactant (CPC) and neutral surfactant (TX-100) retarded the reaction rate. Combination of bipy and SDS is the best choice for chromic acid oxidation of D-galactose to D-galactonic acid in aqueous media although 1,10-phenanthroline is best promoter in absence of micellar catalyst. (C) 2013 Elsevier B.V. All rights reserved.

Agricultural products and by-products are now widely used for removal of hexavalent chromium from waste water. This option is more efficient and less expensive than conventional physicochemical treatments. The purpose of this study was reduction of carcinogenic hexavalent chromium to non-toxic trivalent chromium by use of aqueous extracts of sugar cane bagasse, which contains a variety of reducing components, for example sugar. The rate of this process is accelerated by use of surfactant as catalyst.

In the present investigation, kinetic studies of oxidation of formic acid with and without catalyst and promoter in aqueous acid media were studied under the pseudo-first order conditions [formicacid]T >>[Cr(VI)] T at room temperature. In the 1,10-phenanthroline (phen) promoted path, the cationic Cr(VI) phen complex is the main active oxidant species undergoes a nucleophilic attack by the substrate to form a ternary complex which subsequently experiences a redox decomposition through several steps leading to the products CO2 and H-2 along with the Cr(III) phen complex. The anionic surfactant (i.e., sodium dodecyl sulfate, SDS) and neutral surfactant (i.e., Triton X-100, TX-100) act as catalyst and the reaction undergo simultaneously in both aqueous and micellar phase with an enhanced rate of oxidation in the micellar phase. Whereas the cationic surfactant (i.e., N-cetyl pyridinium chloride, CPC) acts as an inhibitor restricts the reaction to aqueous phase. The observed net enhancement of rate effects has been explained by considering the hydrophobic and electrostatic interaction between the surfactants and reactants. The neutral surfactant TX-100 has been observed as the suitable micellar catalyst for the phen promoted chromic acid oxidation of formic acid.

The kinetics and mechanism of the Ru(III) and Ir(III) catalyzed oxidation reaction of p-chlorobenzaldehyde by ceric(IV) have been studied spectrophotometrically at constant ionic strength of 2.0moldm−3 in the presence and absence of the cationic surfactant N-cetylpyridinium chloride (CPC) at 30°C. The oxidized product p-chlorobenzoic acid was confirmed by the 1H NMR, HR Mass and FTIR spectral analysis. Dramatic rate enhancements have been observed in the oxidation of p-chlorobenzaldehyde by ceric(IV) in the presence of metal ions Ru(III) and Ir(III). The rate of oxidation in the presence of catalyst Ru(III) is much faster than in the Ir(III) catalyzed reaction in micellar media. The observed micellar effect is explained on the basis of reverse CPC micelle formation. This phenomenon was identified with the help of UV Spectra and Scanning Electron Microscopy (SEM) images. The presence of CPC micelles at a certain concentration may increase the effective concentration of the reactant in the hydrophobic part and resulting enhancement of the rate. The substrate undergoes effective collision with the expected positive reactive species Ce(SO4)2+ resulting enhancement of the rate. The enhanced local concentration of reactants in the interfacial region of CPC reverse micelle increases the observed rate. The Ru(III) catalyzed oxidation rate has been found to increase up to 5000 fold in micellar media compared to aqueous media. Ru(III) in combination with CPC is the most effective and suitable catalyst for the catalytic oxidation of p-chlorobenzaldehyde to p-chlorobenzoic acid.

Oxidation of propan-2-ol to acetone was carried out in aqueous media at room temperature. The effect of promoter (PA, bpy, phen), micellar catalyst (SDS, CPC, TX-100) and their combination has been studied. The reactions were performed under the condition [Propan-2-ol]T ≫ [Cr(VI)]T at 30 °C. Then kobs and half life of all the reaction were determined to identify which promoter and which combination are the most effective for this oxidation. Among the promoters phen accelerates the reaction most in aqueous media. In absence of promoters anionic surfactant SDS increases the rate more effectively than neutral surfactant TX-100. CPC retards the rate in comparison to aqueous media. The rate of the oxidation is highest in presence of the combination of bpy and SDS.

Oxidation of organic molecule by metal is very important. Selective oxidants require non aqueous media, which is toxic and hazardous. L-methionine is oxidized to industrially important methyl thiol in micellar media by chromic acid. The overall reaction follows a first order dependency on substrate and hexavalent chromium and second order dependency on hydrogen ion. Here, reverse micelle formation is observed. TX-100 increases the rate where as SDS retards the rate of oxidation.

Abstract Chromic acid oxidation of D-mannitol to mannose has been studied in aqueous media. The effect of promoter (PA, phen and bpy), micellar catalyst (SDS, TX-100 and CPC) and their combination is studied. All the reactions were performed under the condition [D-mannitol]T ≫ [Cr(VI)]T. All the promoters accelerate the reaction rate and the rate is highest in presence of phen. In absence of a promoter the anionic surfactant SDS increases the rate followed by Triton TX-100. The cationic surfactant CPC retards the reaction in comparison to the reaction in aqueous media. Although phen is the best promoter in absence of any surfactant the catalyst combination of bpy and SDS produce a maximum rate enhancement.