•SARS-CoV-2 infections are likely to be more prevalent in the winter season.•Clinical trials reveal vit-D as a potential therapeutic agent against COVID-19.•Vit-D is beneficial against COVID-19 by ...reducing inflammatory response.•Vit-D boosts immune response against SARS-CoV-2 infection.•Vit-D deficiency increases the risk of COVID-19 severity and mortality.
The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is having a disastrous impact on global health. Recently, several studies examined the potential of vitamin D to reduce the effects of SARS-CoV-2 infection by modulating the immune system. Indeed, vitamin D has been found to boost the innate immune system and stimulate the adaptive immune response against SARS-CoV-2 infection. In this review, we provide a comprehensive update of the immunological mechanisms underlying the positive effects of vitamin D in reducing SARS-CoV-2 infection as well as a thorough survey of the recent epidemiological studies and clinical trials that tested vitamin D as a potential therapeutic agent against COVID-19 infection. We believe that a better understanding of the histopathology and immunopathology of the disease as well as the mechanism of vitamin D effects on COVID-19 severity will ultimately pave the way for a more effective prevention and control of this global pandemic.
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•Cr(VI) adsorption has been studied using manganese oxides and boehmite.•Langmuir equation could correlate Cr(VI) adsorption data nicely.•Birnessite showed maximum adsorption at pH 2 ...while others showed a maximum in the pH range of 5.8–8.2.•Cr(VI) adsorption involved more than one type of reaction.•Formation of both outer and inner-sphere Cr(VI) complexes depending on pH.
The concentration of chromium (VI) in the soil is an important environmental concern due to its mobility and acute toxicity. Due to its toxicity, removal of this species is very important. The mobility of Cr(VI) is highly governed by its adsorption onto the mineral surfaces. Manganese oxides are naturally-occurring scavengers and have a significant influence on the distribution, and transport of chromate species. Thus, to understand the fate of chromate species and its removal process, it is important to study chromium (VI) adsorption. In this study, birnessite (δ-MnO2), pyrolusite (β-MnO2), hausmannite (Mn3O4), manganite (γ-MnOOH), boehmite (γ-AlOOH), and Mn-Al binary oxide was used as adsorbents to adsorb Cr(VI) over a range of solution pH and initial Cr(VI) concentrations. A combined approach using the Langmuir and Freundlich models, proton stoichiometry and surface complexation model (SCM) have been used to describe the probable Cr(VI) adsorption process. Birnessite was the most potent adsorbent at low pH. The Langmuir model could describe the equilibrium isotherm data well, suggesting a uniform surface nature. Proton stoichiometry indicated that Cr(VI) adsorption involved more than one type of reaction. The findings confirm that Cr(VI) species bind to functional groups by the inner- and outer-sphere chromate complexes, with the extent of binding dependent on solution pH. The study presented herein can be applied to soils with a variety of surface properties, pH, and Cr (VI) concentrations. The study further advances our understanding of the interaction between Cr(VI) and minerals at the solid-water interface.
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•The greenhouse gas (NOx and SOx) emissions mitigated with material were reviewed.•Various composite materials for the fabrication of novel catalysts were highlighted.•The greenhouse ...gas emission mitigation mechanisms with nanomaterials were reported.•Prospective for the advanced development of greenhouse gas mitigation were suggested.
Great interest has been directed toward developing catalyticdesulfurization and denitrification to remove toxic or environmentally harmful gases before atmospheric emission. The burning of fossil fuels produces sulfur dioxide (SO2) and nitrogen oxides (NOX). The most cost-effective technologies for reducing SOx and NOx emissionsare imperative to mitigate greenhouse gasemissions produced by burning fossil fuels. A huge number of the research paper was published on greenhouse gas mitigation technology over the past two decades, which demonstrates both its importance and its rapid advancement. The various interested research communities would benefit greatly from a review covering key features of new and advanced SOx/NOx mitigation techniques. Thus, the leading SOx and NOx mitigation technologies available for emission and cleaning control of coal-fired power plant flue gases using novel materials have been reviewed in this study. Various physical and chemical properties in the solid catalyticdesulfurization and denitrificationprocess, specifically the structure and active functional groups as well as the stability of the catalyst were highlighted. Research directions for overcoming the challenges involved in SOx and NOx mitigation using solid catalysts/sorbents interface adsorption were suggested. Then the results are clear and compelling with reducing SOx and NOx emissions to mitigate greenhouse gasemissions which will contribute to the practical value of scientific knowledge.
A newly designed composite adsorbent (CpAD), ultra-trace detection ability and a superior adsorption capability to that novel material, was fabricated by functional ligand ...(3-(((5-ethoxybenzenethiol)imino)methyl)–salicylic acid) combining with mesoporous silica. The resultant CpAD was maintained a high surface area with ordered porosity even after successful ligand anchoring. The application of cobalt (Co(II)) detection and adsorption was measured at an optimum experimental protocol with exhibition of significant color visualization. The experiment conditions were optimized based on contact time, solution pH, initial Co(II) concentration and diverse competing metal ions. The CpAD was able to detect the low level Co(II) ion as the detection limit was 0.39 μg/L. The data were clarified that the CpAD was not affected with the existing competing ions and the signal intensity and specific color was observed only toward the Co(II) ion. When used as an adsorbent, the CpAD was demonstrated a very quick adsorption property for the removal of Co(II) ions. The adsorption capability approaches 185.23 mg/g, which is one of the highest capabilities of today's materials. The data also revealed that the removal capabilities of the CpAD for Co(II) ions depended on the material functionality and initial concentration of Co(II) ions. The elution of Co(II) ions from the saturated composite adsorbent was desorbed successfully with 0.30 M HCl. The regenerated adsorbent that remained maintained the high selectivity to Co(II) ions and exhibited almost the same adsorption capacity as that of the original adsorbent. The highest percentage adsorption of Co(II) exceeds 96% in the presence of competing ion, indicating that the CpAD is one of the very suitable composite adsorbent in environmental pollution management.
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•Novel composite adsorbent was designed for efficient Co(II) ion detection & removal.•The adsorbent was efficiently removed Co(II) ion with high selectivity & sensitivity.•The competing ion was not affected the Co(II) capturing by the composite adsorbent.
For the rapid growth of population electrical and electronics equipment waste are generated 20 to 50 million tones in world-wide. Half a tonne of e-waste creates by the resident of advanced country ...in every year. E-waste contains different toxic substances including metals, plastics and refractory oxides which are hazardous or risky for our environment and human wellbeing, thus e-waste management is an essential. Hence, this review outlined the global status of e-waste and its current progress on management worldwide. An exhaustive survey of literature was made on the latest technological approaches in noble and base metals recovery from waste printed circuit boards (PCBs) of electrical and electronic equipment. An emphasis was given to review the most important features of existing industrial routes associated with the metal recovery systems from PCBs. The discussions of green technologies as alternatives of conventional approaches to obtain precious metals from e-waste were overviewed. The application of microbial bioleaching approaches in the extraction metals from e-waste was highlighted. Finally, the concern for the challenges and barriers associated with the e-waste management process in Bangladesh was outlined.
•Current approaches for noble meal recovery from e-waste are reviewed.•Green technologies as alternatives of conformist approaches are discussed.•Contribution of microorganisms to recover noble metal from e-waste is highlighted.
Alkali treated tea waste (ATTW) was investigated as a novel alternative cost-effective natural adsorbent to decontaminate the pollutant of chromium (Cr(VI)) in the polluted water with the variation ...of equilibration time, solution pH, initial Cr(VI) concentration, adsorbent dosage, and temperature with a view to ensuring a safe disposal as well as sustainable management of the discarded bulk quantities of industrial tea leaves wastes. The adsorbent characteristic was confirmed the significant amount of Cr(VI) accumulation onto ATTW surfaces. The adsorption processes were satisfactorily described by pseudo-first order (PFO), pseudo-second order (PSO) and intra-particles diffusion models (IDM) where the PSO model evidently shows a better fitting with the regression coefficient (R2 = 0.994). Exploration of Langmuir, Freundlich, Flory-Huggins, and Temkin isotherm models were also investigated and the best fitting was observed for the Langmuir model as it was produced the highest regression coefficient value (R2 = 0.993). The maximum adsorption ability of ATTW according to the Langmuir model was found to be 158.73 mg/g. These results demonstrate that Cr(VI) adsorption was a complex process involving a physicochemical spontaneous monolayer and multiple rate-limiting states, which was predominantly chemical or chemisorption due to ion-exchange or electrostatic attraction/surface complexation formation, film diffusion and intra-particle diffusion. Furthermore, the substrates exhibited an excellent regeneration capacity upon using 0.10 M HNO3 as eluent and ATTW was reused several cycles without influencing the adsorption performance. The results of this study thus concludes that ATTW could be a promising environmentally friendly and cheap bio-adsorbent for Cr(VI) remediation with profound implications in water and wastewater treatment for a large-scale environmental pollutant clean-up laden with toxic Cr(VI) ions.
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•A natural adsorbent was developed using alkali treated tea waste for pollutant removal.•The developed adsorbent demonstrated high adsorption to clean up wastewater efficiently.•The pollutant removal was predominantly governed by the chemisorption mechanisms.
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•Ligand based nano-composite materials was fabricated for optical Cd(II) capturing.•The specific color was developed upon addition of Cd(II) ions at optimum condition.•Nano-composite ...material was highly selective and sensitive to Cd(II) ions.
In this study, a ligand was anchored with mesoporous silica, named as nano-composite materials, was applied in the detection and adsorption of cadmium (Cd(II)) ions from wastewater samples. The effects of solution pH, color optimization, limit of detection, contact time, initial concentration, ion selectivity and regeneration were systematically performed in the case of detection and adsorption operations. The solution pH was played an important factor both in the case of detection and adsorption, and the optimum pH were selected at 5.50 based on the high absorbance and adsorption ability. Upon addition of Cd(II) ions, the nano-composite materials was provided an excellent color, which was observed by the naked-eye. The detection limit was calculated to be 0.33 µg/L, which was lower than the permissible limit. Therefore, the Cd(II) ions was detected without using any sophisticated instruments. The equilibrium isotherm has been analyzed using Langmuir isotherm models, and the maximum adsorption capacity was 148.32 mg/g. The results clarified that the nano-composite material had the higher selectivity towards Cd(II) ions even in the presence of high concentration of divers metal ions. The material was reused in several cycles after elution operation with a suitable eluent of 0.25 M HCl. The nano-composite materials exhibited an excellent reusability because of its remarkable mechanical strength and highly efficient elution/regeneration operations ability. In the static treatment process, after seven cycles, Cd(II) ions was adsorbed efficiently and holding over 93% adsorption efficiency. The developed ligand functionalized nano-composite materials is quite simple and rapid with excellent repeatability for Cd(II) ions capturing and has a great potential for potential scale up for field application in real wastewater samples.
In this paper, a 12-transistor radiation tolerant SRAM cell has been proposed in 16-nm CMOS predictive technology model. The proposed 12T SRAM cell offers higher immunity to soft error than all other ...compared memory cells. The proposed SRAM cell proves its robustness against radiation strike by showing the largest amount (4.1 fC) of critical charge (Q
C
) among all the comparison SRAM cells. The proposed 12T cell consumes 48.03%, and 48.68% lower hold power than QUCCE 12T and QUCCE 10T SRAM cell, respectively. It exhibits 79.92%, 33.77%, 84.84%, and 59.97% shorter read delay compared to 6T SRAM, QUCCE 10T, WE QUATRO, and QUCCE 12T, respectively at a nominal supply voltage of 0.7 V. In terms of write delay the proposed 12T exhibits 68.49% shorter write delay as compared with QUCCE 10T. The proposed circuit has higher RSNM as compared to other SRAM cells and consumes lesser silicon area than other comparison cells except 6T and QUCCE 10T SRAM cell. The read stability of proposed 12T is 3.10×, 1.76×, 2.09×, 1.62 × times higher than 6T SRAM, QUCCE 10T, WE QUATRO, and QUCCE 12T, respectively. The proposed 12T exhibits 65.85%, 41.46%, 26.82%, and 41.46% improvement in critical charge (
Q
C
) in comparison with 6T SRAM, QUCCE 10T, WE QUATRO and QUCCE 12T, respectively. However, these improvements are achieved at the cost of marginal degradation of write margin as compared to 6T, QUCCE 10T, WE QUATRO and QUCCE 12T SRAM cells, respectively. In terms of area, the proposed 12T acquires lesser area as compared to QUCCE 12T (6.32%) and WE QUATRO (12%). Hence, the proposed 12T SRAM cell is a promising selection for future highly reliable terrestrial applications.
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•Novel ligand based sensor material was prepared for rapid Cd(II) ion detection and adsorption.•The sensor can be sensitively detected the Cd(II) ion with high efficiency.•Novel ...sensor material was able to use in the real sample treatment in on-site analyses.
In this study, an optical sensor material was fabricated for sustainable detection and adsorption of cadmium (Cd(II)) ion in aqueous solution with specific color formation. The sulphur containing organic functional ligand was grafted onto the mesoporous silica monolith via direct immobilization method through chemical and electrostatic interaction. The sensor material was exhibited an enhanced sensitivity and distinct color and spectral response to Cd(II) ion in aqueous solution. Larger immobilization capacity of organic ligand on the carrier silica to stronger accumulation for Cd(II), and smaller one made the optical sensor have a faster and more sensitive response to the Cd(II) ion at optimum condition. The influence of pH, limit of detection, ion selectivity and Cd(II) ion adsorption capacity and the effect of eluent for the stripping of Cd(II) ion from sensor material over elution efficiency were measured. The sensor material offered a simple procedure in ultra-trace Cd(II) sensing optically without using high tech instruments. The Cd(II) ion detection limit of the presented sensor material was 0.36 µg/L at optimum conditions. The proposed sensor was exhibited with large surface area-to-volume ratios and uniformly mesostructures shaped pores that were actively working to selective capturing of Cd(II) ion. The adsorption data were well fitted to the Langmuir model and the maximum adsorption capacity was 167.33 mg/g. The sensor was capable to detected the Cd(II) ion even in the presence of a high amount of coexisting diverse metal ions. Moreover, the adsorbed Cd(II) ion was completely eluted with 0.30 M HCl and simultaneously regenerated into the initial form for the next operation after washing with water. Therefore, the optical sensor material exhibited good stability and reusability which made it efficient for various adsorptive removal and detection applications.
This review article provides a comprehensive overview of fiber and nanoparticle reinforced polymer matrix composites (PMC) for their damping and sound absorption properties. It explains the mechanism ...of damping and sound absorption properties of the material as a first step. Further, the paper discusses the governing parameters of materials responsible for the variation of the material's damping and sound absorption properties. The performance of damping and sound absorption properties of different fibrous materials, including natural fibers, synthetic fibers, and different nanoparticles, including carbon nanotube, graphene nanotubes-based PMC are reviewed. The role of the interfacial region, density, fiber thickness, porosity, viscoelasticity, and friction on the damping and sound absorption properties has been discussed. The sound absorption properties of much denser, thicker, and more porous materials are higher than those of less dense, thinner, and less porous materials because of their higher polymerization. The damping performance of the PMC was observed to be increased with the decrease in the bonding of the interface region between fiber and matrix. The conclusion of this review provides several useful recommendations for the further development of PMC with the desired damping and sound absorption properties.
•Influence of thickness, porosity, viscoelasticity, and density of porous materials on the acoustic absorption property.•Significance of Interfacial region in controlling the damping property of PMC.•The effect of inclusion of nanoparticles in the polymer matrix on damping and sound absorption property.•Challenges and future scope for further improvement of polymer-based composites with improved damping and SAC.