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Surfactant stabilized Gold (Au) nanomaterials (NMs) have been documented extensively in recent years for numerous sensing applications in the academic literature. Despite the crucial role these surfactants play in the sensing applications, the comprehensive reviews that highlights the fundamentals associated with these assemblies and impact of these surfactants on the properties and sensing mechanisms are still quite scare. This review is an attempt in organizing the vast literature associated with this domain by providing critical insights into the fundamentals, preparation methodologies and sensing mechanisms of these surfactant stabilized Au NMs. For the simplification, the surfactants are divided into the typical and advanced surfactants and the Au NMs are classified into Au nanoparticles (NPs) and Au nanoclusters (NCs) depending upon the complexity in structure and size of the NMs respectively. The preparative methodologies are also elaborated for enhancing the understanding of the readers regarding such assemblies. The case studies regarding surfactant stabilized Au NMs were further divided into colorimetric sensors, surface plasmonic resonance (SPR) based sensors, luminescence-based sensors, and electrochemical/electrical sensors depending upon the property utilized by the sensor for the sensing of an analyte. Future perspectives are also discussed in detail for the researchers looking for further progress in that particular research domain.
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Nanopartículas Metálicas , Nanoestruturas , Colorimetria , Ouro/química , Nanopartículas Metálicas/química , Nanoestruturas/química , TensoativosRESUMO
In this study, zinc ferrite nanoparticles (ZF-NPs) were synthesized using aqueous seed extract of Piper nigrum as a bio-reducing and stabilizing agent. FTIR, SEM, FE-SEM, XRD, and TGA have been used for characterizing ZF-NPs. The results showed that Piper nigrum stabilized ZF-NPs have high purity and size range of 60-80 nm. The performance of the ZF-NPs has been investigated by photocatalytic reduction of methylene blue (MB) in the presence of sunlight. The factors responsible for affecting the degradation values of the reaction were also explored for developing a better understanding of the phenomenon.
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Nanopartículas Metálicas , Nanopartículas , Antibacterianos , Biodegradação Ambiental , Compostos Férricos , Azul de Metileno , ZincoRESUMO
This review is based on the adsorption characteristics of sorghum (Sorghum bicolor) for removal of heavy metals from aqueous media. Different parameters like pH, temperature of the medium, sorghum concentration, sorghum particle size, contact time, stirring speed and heavy metal concentration control the adsorption efficiency of sorghum biomass for heavy metal ions. Sorghum biomass showed maximum efficiency for removal of heavy metal ions in the pH range of 5 to 6. It is an agricultural waste and is regarded as the cheapest biosorbent, having high adsorption capacity for heavy metals as compared to other reported adsorbents, for the treatment of heavy metal polluted wastewater. Adsorption of heavy metal ions onto sorghum biomass follows pseudo second order kinetics. Best fitted adsorption isotherm models for removal of heavy metal ions on sorghum biomass are Langmuir and Freundlich adsorption isotherm models. Thermodynamic aspects of heavy metal ions adsorption onto sorghum biomass have also been elaborated in this review article. How adsorption efficiency of sorghum biomass can be improved by different physical and chemical treatments in future has also been elaborated. This review article will be highly useful for researchers working in the field of water treatment via biosorption processing. The quantitative demonstrated efficiency of sorghum biomass for various heavy metal ions has also been highlighted in different sections of this review article.
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Metais Pesados/química , Sorghum/química , Poluentes Químicos da Água/química , Adsorção , Biomassa , Concentração de Íons de Hidrogênio , Cinética , Temperatura , Termodinâmica , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias , Purificação da Água/métodosRESUMO
BACKGROUND: In the case of COVID-19 patients, it has been observed that the immune system of the infected person exhibits an extreme inflammatory response known as cytokine release syndrome (CRS) where the inflammatory cytokines are swiftly produced in quite large amounts in response to infective stimuli. Numerous case studies of COVID-19 patients with severe symptoms have documented the presence of higher plasma concentrations of human interleukin-6 (IL-6), which suggests that IL-6 is a crucial factor in the pathophysiology of the disease. In order to prevent CRS in COVID-19 patients, the drugs that can exhibit binding interactions with IL-6 and block the signaling pathways to decrease the IL-6 activity may be repurposed. METHODS: This research work focused on molecular docking-based screening of the drugs celecoxib (CXB) and dexamethasone (DME) to explore their potential to interact with the binding sites of IL-6 protein and reduce the hyper-activation of IL-6 in the infected personnel. RESULTS: Both of the drugs were observed to bind with the IL-6 (IL-6 receptor alpha chain) and IL-6Rα receptor with the respective affinities of -7.3 kcal/mol and -6.3 kcal/mol, respectively, for CXB and DME. Moreover, various types of binding interactions of the drugs with the target proteins were also observed in the docking studies. The dynamic behaviors of IL-6/IL-6Rα in complex with the drugs were also explored through molecular dynamics simulation analysis. The results indicated significant stabilities of the acquired drug-protein complexes up to 100 ns. CONCLUSION: The findings of this study have suggested the potential of the drugs studied to be utilized as antagonists for countering CRS in COVID-19 ailment. This study presents the studied drugs as promising candidates both for the clinical and pre-clinical treatment of COVID-19.
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COVID-19 , Humanos , Síndrome da Liberação de Citocina/tratamento farmacológico , Interleucina-6 , Celecoxib/farmacologia , Celecoxib/uso terapêutico , SARS-CoV-2 , Simulação de Acoplamento Molecular , Tratamento Farmacológico da COVID-19 , Dexametasona/farmacologia , Dexametasona/uso terapêutico , Inteligência ArtificialRESUMO
In recent years, the growing research interests in the applications of plant and fruit extracts (synthetic/stabilization materials for the nanomaterials, medicinal applications, functional foods, and nutraceuticals) have led to the development of new analytical techniques to be utilized for identifying numerous properties of these extracts. One of the main properties essential for the applicability of these plant extracts is the antioxidant capacity (AOC) that is conventionally determined by spectrophotometric techniques. Nowadays, electrochemical methodologies are emerging as alternative tools for quantifying this particular property of the extract. These methodologies address numerous drawbacks of the conventional spectroscopic approach, such as the utilization of expensive and hazardous solvents, extensive sample pre-treatment requirements, long reaction times, low sensitivity, etc. The electrochemical methodologies discussed in this review include cyclic voltammetry (CV), square wave voltammetry (SWV), differential pulse voltammetry (DPV), and chronoamperometry (CAP). This review presents a critical comparison between both the conventional and electrochemical approaches for the quantification of the parameter of AOC and discusses the numerous applications of the obtained bioextracts based on the AOC parameter.
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Potential hazardous effects caused by non-biodegradable plastics are considered to be one of the most widely discussed and notable challenges of the 21st century. To address this particular problem, immense efforts have been devoted to the preparation of biodegradable plastics material. This green approach mitigates the major drawbacks e.g. improper waste management, low degradation rates, waste accumulation in water reservoirs and harmful chemical reagents hence providing a natural, economical and biodegradable alternative to the customarily employed non-biodegradable plastics. This review provides an insight into recently engineered biodegradable plastics used for packaging applications. Properties such as barrier/permeation indexes, thermal, electrical and mechanical characteristics of the biodegradable plastics are considered in detail for developing an understanding regarding the fundamentals of biodegradable materials. Recent literature (2010-2018) was classified according to the composition and nature of the used material. Materials such as polylactic acid, polyhydroxyalkanoates, polyhydroxybutyrate, polycaprolactone, starch and cellulose were comprehensively discussed along with their properties and blending agents.
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Plásticos Biodegradáveis/análise , Análise de Alimentos , Contaminação de Alimentos/análise , Embalagem de Alimentos , Biodegradação AmbientalRESUMO
Extraction of toxic heavy metal ions from aqueous medium using poly(N-isopropylmethacrylamide-acrylic acid) (P(NiPmA-Ac)) microgels as adsorbent has been investigated in present study. P(NiPmA-Ac) microgel particles were prepared by free radical precipitation polymerization in aqueous medium. Morphology and size of the prepared microgel particles was investigated by transmission electron microscopy (TEM). The Fourier transform infrared (FT-IR) analysis of pure and metal ion-loaded microgel particles was performed to confirm the presence of various functionalities of microgel particles and their interaction with metal ions extracted from aqueous medium. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to investigate the thermal stability and thermal behavior of pure and metal ion-loaded microgel particles. Contents of metal ions loaded into microgel particles were determined by TGA analysis. It was observed that P(NiPmA-Ac) particles have a potential to extract Cu2+ and Co2+ ions from aqueous medium. The Freundlich adsorption isotherm model best interprets the adsorption process as compared with the Langmuir model. Value of R2 according to the Freundlich adsorption isotherm was found to be 0.994 and 0.993 for Cu2+ and Co2+ ions, respectively. Adsorption process was followed by pseudo second order kinetics for Cu2+ and Co2+ ions with R2 values of 0.999 for both metal ions. Thermodynamic study showed that adsorption process was spontaneous, feasible, and endothermic in nature. Entropy was decreased at adsorbate-adsorbent interface during adsorption process. Adsorbent was recycled and reused for removal of Cu2+ ions, and adsorption efficiency was found to be maintained up to three cycles. Microgel particles also have ability to extract Cu2+ ions efficiently from electroplating wastewater. Graphical abstract.
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Cobre , Poluentes Químicos da Água/análise , Acrilatos , Adsorção , Cobalto , Concentração de Íons de Hidrogênio , Cinética , Microgéis , Espectroscopia de Infravermelho com Transformada de Fourier , Polímeros Responsivos a Estímulos , TermodinâmicaRESUMO
Conversion of nitroaniline (NA), a highly toxic pollutant that has been released into aquatic systems due to unmanaged industrial development in recent years, into the less harmful or a useful counterpart is the need of the hour. Various methods for its conversion and removal have been explored. Owing to its nominal features of advanced effectiveness, the chemical reduction of 4-NA using various different nanocatalytic systems is one such approach that has attracted tremendous interest over the past few years. The academic literature has been confined to case studies involving silver (Ag) and gold (Au) nanoparticles, as these are the two most widely used materials for the synthesis of nanocatalytic assemblies. Focus has also been given to sodium borohydride (NaBH4), which is used as a reductant during the chemical reduction of NA. This systematic review summarizes the fundamentals associated with the catalytic degradation of 4-NA, and presents a comprehensive and critical study of the latest modifications used in the synthesis of these catalytic systems. In addition, the kinetics, mechanisms, thermodynamics, as well as the future directions required for understanding this model reaction, have been provided in this particular study.
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Nitrophenol is common carcinogenic pollutant known for its adverse effects on human beings and aquatic life. During the last few decades, the chemical reduction of nitrophenol compounds has been widely reported as the advanced removal methodology for such hazardous dyes from aqueous reservoirs. Many researchers have utilized different nanocatalytic systems using sodium borohydride (NaBH4) as the reducing agent for acquiring industrially useful reduction product of aminophenol by carrying out the chemical reduction of nitrophenols. Polymeric material supported monometallic nanoparticles are widely reported catalyst for the degradation of 2-nitrophenol (2-NP) and 4-nitrophenol (4-NP). This review critically discusses the pros and cons of numerous supporting mediums of nanocatalytic assemblies used for the immobilization of nanomaterials. Mechanism and kinetic analysis of the reduction reaction of 2-NP and 4-NP have also been explained in this study. In addition, recent literature has also been effectively summarized in the tabular form for developing a better understanding of the reader. Pictorial representation of key nanocatalytic assemblies and catalytic reduction mechanism has also been narrated in this study.