Online customer reviews, considered as electronic word of mouth, have become very useful in the era of e-commerce as they facilitate future purchase decisions. The present study discusses the central ...and peripheral sources of influence, such as the content of the review, star rating, review length, and the total number of votes on the perceived usefulness of the review. It analyses reviews from Amazon.com on three products, namely, a videogame, digital music, and a grocery item. Using text mining, the study uncovers sentiment polarity, identifies sentiment patterns, and finally, analyses the perceived usefulness of reviews under the moderation effect. The study establishes that the impact of the central route is not significant for search goods. The study concludes that peripheral sources have a significant impact on the search products. Our study provides insights on how marketing strategies can be formulated by online retailers based on the product type.
Suaeda monoica Forssk. ex J.F.Gmel. (Amaranthaceae), a mangrove associate and ethno-medicinal herb of Indian Sundarbans, was investigated as a promising source of bioactive compounds. Various polar ...and nonpolar solvent extracts of the leaf and root-shoot parts of the plant exhibited antioxidant, antibacterial, antifungal, allelopathic, mosquitocidal, antihaemolytic and antidiuretic potential. Moreover, to meet pharmacological requirements, the antioxidant ability of the plant was validated by both chemical and biological analyses. Extraction yield and presence of different phytochemicals like phenolics, flavonoids, tannins and saponins were compared in various solvent-extracted fractions. Principle component analysis revealed that the antioxidant property present in different extracts maintained a positive correlation with the occurrence of polyphenols (phenolics, tannins and flavonoids). Biochemical evaluation, HPLC examination and GC-MS analysis showed a differential level of the presence of various phytochemicals in different solvent extracts. In contrast to mosquitocidal, antioxidant, antihaemolytic and phytotoxic properties which were observed to be dominant in polar solvent extracts, maximum antibacterial potency was detected in nonpolar
-hexane fractions. Overall, the plant extract is nontoxic in nature and a dose amounting to 3,000 mg/kg was well tolerated by Swiss albino mice. A combination of HPLC and GC-MS analyses showed the presence of a large number of structurally diverse phytochemicals, many of which had already been reported as insecticidal, mosquitocidal, antibacterial, herbicidal, antidiuretic, antioxidant and anti-haemolytic compounds. All these findings support that the least explored traditional edible medicinal mangrove associate S.monoica is enriched with multiple bioactive molecules and may be considered as one of the richest sources of various lead molecules of pharmaceutical importance.
•Characterization of polycyclic aromatic hydrocarbon dioxygenase in Sphingobium sp.•In silico analysis of large catalytic pocket and unique substrate access channel.•Cloning and expression of ...multi-component dioxygenase.•Evaluation of broad substrate specificity, guided by molecular docking analysis.
A Rieske non-heme iron ring-hydroxylating oxygenase (RHO) from Sphingobium sp. PNB involved in the initial oxidation of a wide range of low and high molecular weight polycyclic aromatic hydrocarbons (PAHs) was investigated. The RHO was shown to comprise of the gene products of distantly located ahdA1f-ahdA2f, ahdA3 and ahdA4 genes, which encoded the oxygenase α- and β-subunits, ferredoxin and reductase, respectively. In silico structural analysis of AhdA1f revealed a very large substrate-binding pocket, satisfying the spatial requirements to accommodate high molecular weight substrates. In addition, an atypical substrate access channel was noticed from the topology analysis of the oxygenase. Guided by molecular docking studies, dioxygenation of several PAHs as well as alkyl- and aryl benzenes was examined with the recombinant AhdA1fA2f expressed in Escherichia coli. Chromatographic and mass spectrometric analyses confirmed that AhdA1fA2f displays broad substrate specificity towards a wide range of aromatic hydrocarbons including potential xenobiotics, demonstrating metabolic robustness of strain PNB.
Nanocomposite-based ceramic membrane with microbubble is an emerging hybrid technology for treating recalcitrant organics in wastewater. The current work is based on the synergistic effect of ...photocatalyst, microbubble, and membrane separation for enhanced degradation of Bismarck brown R, which is otherwise very low in the standalone process. In this study, we have fabricated a bench-scale membrane set up of submerged type, modified tubular membrane with the novel Zeolite A@ZnO1−X nanocomposite, and detailed analytical characteristics are investigated. The thin layer coating (average thickness 24.6 µm) of oxygen-deficient ZA@ZnO1−X photocatalyst gives a high photocatalytic efficiency under visible light without hampering the rejection rate. Here, we have treated Bismarck brown R contaminated wastewater in our prototype setup with simulated and natural wastewater collected from a local dying factory. The operational parameters such as Bismarck brown R concentration, solution pH, temperature, and flux are varied and analyzed optimized reaction conditions favorable for actual wastewater treatment. The hybrid ZA@ZnO1−X nanocomposite-based tubular membrane improved the degradation of natural wastewater to 95.4 % decolorization and 94 % COD removal in 90 mins at pH 8.15, solution flux 120 ml/min and temperature 30 °C. The scavenging experiment resolved responsible reactive species for organic dye degradation: holes and HO•. The tentative mechanistic degradation pathway involved homolytic cleavage of the azo bond followed by phenyl radical generation to a small intermediate of hydroxyquinol. This work represents an efficient alternative to conventional membrane technology with lesser membrane fouling tendency and enhanced catalytic efficiency in assistance with microbubbles simultaneously.
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Arsenic (As), cited as the most hazardous substance by the U.S. Agency for Toxic Substance and Disease Registry (ATSDR, 2005), is an ubiquitous metalloid which when ingested for prolonged periods ...cause extensive health effects leading to ultimate untimely death. Plants and microbes can help mitigate soil and groundwater As problem since they have evolved elaborate detoxification machineries against this toxic metalloid as a result of their coexistence with this since the origin of life on earth. Utilization of the phytoremediation and bioremediation potential of the plants and microbes, respectively, is now regarded as two innovative tools that encompass biology, geology, biotechnology and allied sciences with cutting edge applications for sustainable mitigation of As epidemic. Discovery of As hyperaccumulating plants that uptake and concentrate large amounts of this toxic metalloid in their shoots or roots offered new hope to As phytoremediation, solar power based nature's own green remediation. This review focuses on how phytoremediation and bioremediation can be merged together to form an integrated phytobial remediation which could synergistically achieve the goal of large scale removal of As from soil, sediment and groundwater and overcome the drawbacks of the either processes alone. The review also points to the feasibility of the introduction of transgenic plants and microbes that bring new hope for more efficient treatment of As. The review identifies one critical research gap on the importance of remediation of As contaminated groundwater not only for drinking purpose but also for irrigation purpose and stresses that more research should be conducted on the use of constructed wetland, one of the most suitable areas of application of phytobial remediation. Finally the review has narrowed down on different phytoinvestigation and phytodisposal methods, which constitute the most essential and the most difficult part of pilot scale and field scale applications of phytoremediation programs.
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•Bioremediation of As is microbe mediated transformation, adsorption & accumulation of As.•Phytoremediation of As is plant mediated removal of As from soil and groundwater.•Bioremediation and phytoremediation should be integrated for effective removal of As.•Constructed wetland can be used for applying phytobialremediation of As.•More research should be made on arsenic recycling from disposed biomass.
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A facile chemoselective one-pot strategy for the deprotection of oxime has been developed using Fe0-polyaniline composite nanofiber (Fe0-PANI), as a catalyst. Nano material based ...Fe0-PANI catalyst has been synthesized via in-situ polymerization of ANI monomer and followed by reductive deposition of Fe0 onto PANI matrix. The catalyst was characterized by FE-SEM, HR-TEM, BET, XRD, ATR-FTIR, XPS and VSM techniques. The scope of the transformation was studied for aryl, alkyl and heteroarylketoxime with excellent chemoselectivity (>99%). Mechanistic investigations suggested the involvement of a cationic intermediate with Fe3+ active catalytic species. Substituent effect showed a linear free energy relationship. The activation energy (Ea) was calculated to be 17.46 kJ mol−1 for acetophenone oxime to acetophenone conversion. The recyclability of the catalyst demonstrated up to 10 cycles without any significant loss of efficiency. Based on the preliminary experiments a plausible mechanism has been proposed involving a carbocationic intermediate.
Polycyclic aromatic hydrocarbons (PAHs) comprise a group of priority organic pollutants that are toxic and/or carcinogenic. Phenanthrene, the simplest PAH among recognized priority pollutants, is ...commonly used as a model compound for the study of PAH biodegradation. Sphingobium sp. strain PNB, capable of degrading phenanthrene as a sole carbon and energy source, was isolated from a municipal waste-contaminated soil sample. A combination of chromatographic and spectrometric analyses, together with oxygen uptake and enzyme activity studies, suggested the presence of phenanthrene degradation pathways in this strain. Identification of metabolites suggested that initial dioxygenation of phenanthrene took place at both 3,4- and 1,2-carbon positions; meta-cleavage of resultant diols led to the formation of 1-hydroxy-2-naphthoic acid and 2-hydroxy-1-naphthoic acid, respectively. The hydroxynaphthoic acids, in turn, were metabolized by a meta-cleavage pathway(s), leading to the formation of 2,2-dicarboxychromene and 2-hydroxychromene-2-glyoxylic acid, respectively. These metabolites were subsequently transformed to catechol via salicylic acid, which further proceeds towards the tricarboxylic acid cycle leading to complete mineralization of the compound phenanthrene. The present study establishes the metabolism of hydroxynaphthoic acids by a meta-cleavage pathway in the degradation of phenanthrene, expanding our current understanding of microbial degradation of PAHs.
Formation of extracellular polymeric substances (EPS) is a crucial step for bacterial biofilm growth. The dependence of EPS composition on growth substrate and conditioning of the latter is thus of ...primary importance. We present results of studies on the growth of biofilms of two different strains each, of the Gram-negative bacteria Escherichia coli and Klebsiella pneumoniae, on four polymers used commonly in indwelling medical devices polyethene, polypropylene, polycarbonate, and polytetrafluoroethyleneimmersed in bovine serum albumin (BSA) for 24 h. The polymer substrates are studied before and after immersing in BSA for 9 and 24 h, using contact angle measurement (CAM) and field emission scanning electron microscopy (FE-SEM) to extract, respectively, the “philicity” φ (defined as −cos θ, where θ is the contact angle of the liquid on the solid at a particular temperature and ambient pressure) and spatial Hirsch parameter H (defined from the relation F(r) ∼ r 2H , where F(r) is the mean squared density fluctuation at the sample surface). H = 0.5, <0.5, or >0.5 signifies no correlation, anticorrelation, and correlation, respectively. The substrates are seen to transform from large hydrophobicity to near amphiphilicity with the formation of a BSA conditioning surface layer, and the H-values distinguish the length scales of 100, 500, and 2000 nm, with the anticorrelation increasing with length scale. Biofilms of E. coli did not grow on bare PTFE and HDPE substrates. Biofilms grown on BSA-covered surfaces are studied with CAM, FE-SEM, Fourier transform infrared (FTIR), and surface-enhanced Raman spectroscopy (SERS). Both spectra and φ-values were independent of bacterial species but dependent on the polymer, while H-values show some bacterial variation. Thus, EPS composition and wetting properties of the corresponding bacterial biofilms seem to be decided by the interaction of the conditioning BSA layer with the specific polymer substrate.
Aim: Frontline Health Care Workers (FLHCWs) are the key workforce in the fight against ongoing COVID-19 pandemic. They hail from the community and are responsible for supporting the health system in ...generating awareness, implementing preventive strategies, contact tracing and isolating potential cases. In their job responsibilities, FLHCWs thus may perceive heightened risk of exposure to the virus, leading to overwhelming emotional response and psychological distress. The objective of this study was to investigate risk perception, cognitive awareness and emotional responses among FLHCWs trained to deal with Covid 19, to identify unmet needs of this training in India. Methods: A cross-sectional study was conducted in a total of 131 frontline workers selected by a multistage sampling process from two states (Odisha and Himachal Pradesh) of India. The FLHCWs were interviewed personally (when feasible) with the help of a predesigned pretested semi-structured questionnaire. Results: The findings suggested that majority (90%) of the FLHCWs perceived that they are susceptible to nCoV-19 infection and 77.1% of FLHCWs felt high probability of them getting infected with the nCoV-19. Almost 90% of them responded that it is something they think about all the time and 41% of FLHCWs admitted that they feel helpless in the situation. About 63% of FLHCWs perceived that the nCoV-19 infection was a severe illness and 35% perceived it to be very severe and life threatening. Although most of them had received some unstructured and non-uniform training on preventive measures against COVID-19, yet only 38% felt that the knowledge was adequate to protect themselves from the nCoV-19 infection. The training sessions lacked psychological component for capacitating them with coping skills to address their emotional and psychological responses. Conclusion: The FLHCWs experienced heightened risk perception and symptoms of emotional distress in significant numbers even after trainings. A more inclusive public health policy dialogue to address the emotional and psychological coping skills is needed for capacitation of these frontline workers to address the challenges of Pandemic response now and in future. Conflicts of interests: None declared. Acknowledgments: We would like to thank all participants to our study, whose time is even more precious in this difficult situation for all the country, who participated.
The present article attempts to interpret the modulation of photophysical properties of isophthalic acid (IPA) through its amino 5-amino isophthalic acid (5-amino IPA) and azido 5-azido isophthalic ...acid (5-azido IPA) substituted derivatives which are chemically potent organic ligands. The ground state structure-reactivity correlation of 5-amino IPA and 5-azido IPA has been deciphered through computational studies. The computed energetics show significant interaction feasibility of the substituted ligand systems with the biomimetic systems which is further validated experimentally. The binding interaction of the probes with oppositely polarized functionalization is studied to be significant with cetyltrimethylammonium bromide (CTAB) and bovine serum albumin (BSA) with the amino functionalized derivative having a comparatively stronger binding constant value. The steady-state absorption and fluorescence study establish significant modification of polarity of the heteronuclear probes. The micro polarity study in water-dioxane mixtures enables determination of polarity of 5-amino IPA in CTAB and BSA unlike 5-azido IPA. Presence of an overlapping region between the emission spectrum of BSA and the absorption spectrum of the probes as probable donor-acceptor pair are also scrutinized via the steady-state fluorescence studies. The photophysical behavior of 5-amino IPA is observed to be somewhat dissimilar to that of 5-azido IPA.
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