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A review of hierarchical nanostructures of TiO2: Advances and applications
In the past few decades, extensive studies have been carried out on TiO2 nanostructures having hierarchical morphologies and their applications in diverse fields. By controlling the size and composition of the different TiO2 morphologies, new and improved properties have been realized, leading to significant advancements in materials chemistry, in the broad areas of energy and environment. The improved efficiency and wide applications of these materials are attributed to their physicochemical properties such as stability, efficient electronic and ionic charge transfer, higher specific surface area, etc. In this review, we discuss the different morphologies of hierarchical TiO2 nanoparticles and the properties that have been influenced by these morphologies, enabling their diverse applications. Several composites using the different TiO2 hierarchical forms have been synthesized which too find wide applications. The excellent physical properties of zero, one, two, and three-dimensional TiO2 nanostructures, the relationship between the morphologies of TiO2 nanostructures, and their activities in energy and environment applications have been discussed. 2021 The Author(s) -
Advances in Carbon-Element Bond Construction under Chan-Lam Cross-Coupling Conditions: A Second Decade
Copper-mediated carbon-heteroatom bond-forming reactions involving a wide range of substrates have been in the spotlight for many organic chemists. This review highlights developments between 2010 and 2019 in both stoichiometric and catalytic copper-mediated reactions, and also examples of nickel-mediated reactions, under modified Chan-Lam cross-coupling conditions using various nucleophiles; examples include chemo- and regioselective N-arylations or O-arylations. The utilization of various nucleophiles as coupling partners together with reaction optimization (including the choice of copper source, ligands, base, and other additives), limitations, scope, and mechanisms are examined; these have benefitted the development of efficient and milder methods. The synthesis of medicinally valuable or pharmaceutically important nitrogen heterocycles, including isotope-labeled compounds, is also included. Chan-Lam coupling reaction can now form twelve different C-element bonds, making it one of the most diverse and mild reactions known in organic chemistry. 1 Introduction 2 Construction of C-N and C-O Bonds 2.1 C-N Bond Formation 2.1.1 Original Discovery via Stoichiometric Copper-Mediated C-N Bond Formation 2.1.2 Copper-Catalyzed C-N Bond Formation 2.1.3 Coupling with Azides, Sulfoximines, and Sulfonediimines as Nitrogen Nucleophiles 2.1.4 Coupling with N, N -Dialkylhydroxylamines 2.1.5 Enolate Coupling with sp 3-Carbon Nucleophiles 2.1.6 Nickel-Catalyzed Chan-Lam Coupling 2.1.7 Coupling with Amino Acids 2.1.8 Coupling with Alkylboron Reagents 2.1.9 Coupling with Electron-Deficient Heteroarylamines 2.1.10 Selective C-N Bond Formation for the Synthesis of Heterocycle-Containing Compounds 2.1.11 Using Sulfonato-imino Copper(II) Complexes 2.2 C-O Bond Formation 2.2.1 Coupling with (Hetero)arylboron Reagents 2.2.2 Coupling with Alkyl- and Alkenylboron Reagents 3 C-Element (Element = S, P, C, F, Cl, Br, I, Se, Te, At) Bond Forma tion under Modified Chan-Lam Conditions 4 Conclusions. 2021 Georg Thieme Verlag. All rights reserved. -
Medicinal plants, phytochemicals, and herbs to combat viral pathogens including sars-cov-2
The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome corona virus-2 (SARS-CoV-2), is the most important health issue, internationally. With no specific and effective antiviral therapy for COVID-19, new or repurposed antiviral are urgently needed. Phytochemicals pose a ray of hope for human health during this pandemic, and a great deal of research is concentrated on it. Phytochemicals have been used as antiviral agents against several viruses since they could inhibit several viruses via different mechanisms of direct inhibition either at the viral entry point or the replication stages and via immunomodulation potentials. Recent evidence also suggests that some plants and its components have shown promising antiviral properties against SARS-CoV-2. This review summarizes certain phytochemical agents along with their mode of actions and potential antiviral activities against important viral pathogens. A special focus has been given on medicinal plants and their extracts as well as herbs which have shown promising results to combat SARS-CoV-2 infection and can be useful in treating patients with COVID-19 as alternatives for treatment under phytotherapy approaches during this devastating pandemic situation. 2021 by the authors. Licensee MDPI, Basel, Switzerland. -
Electrochemical sensors using conducting polymer/noble metal nanoparticle nanocomposites for the detection of various analytes: a review
Abstract: Conducting polymer/noble metal nanoparticle (CP/NMNP) composites have made a history of sorts since its inception in the field of electrochemical research, which resulted to be an impetus for scientists to indulge and explore the opportunities it can unleash. This review throws light on the synergic effects and the enhancement in the electrocatalytic activity on dispersing noble metal particles on conducting polymers. This review aids the readers to analyse the electrochemical sensing efficiency of CP/NMNP composites, and provides a platform for the researchers to engineer and develop CP/NMNP composite materials for electrochemical sensing. This work also draws the attention of the readers to the application of NMNP (Ag, Au, Pt, Pd, Ir, and Ru) dispersed on CPs [polyaniline (PANI), polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT)] and their composites with other materials like carbon nanotubes (CNTs), graphene, zeolites, and peptide nanotubes (PNTs) for sensing of various analytes. Graphic abstract: This review draws the attention of the readers to the application of NMNP (Ag, Au, Pt, Pd, Ir and Ru) dispersed on CPs (polyaniline (PANI), polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT)) and their composites with other materials like carbon nanotubes (CNTs), graphene, zeolites, and peptide nanotubes (PNTs) for sensing of various analytes.[Figure not available: see fulltext.]. 2021, Islamic Azad University. -
Evaluation of a gamified learning experience: Analysis of factors that impact the effectiveness of a gamified experience; [Avaliao de uma expericia de aprendizagem gamificada: Anise dos fatores que afetam a eficia de uma expericia gamificada]
Gamification has gone through a faddish cycle. It first gained prominence around 2012 and was quickly abandoned, as practitioners did not achieve the outcomes they expected. According to Gartner's Hype Cycle, Gamification is at a point at which one might expect wide scale adoption. However, if history is not to repeat itself and results are to be achieved as theoretically predicted, a deeper understanding of the concept is essential. In the current study, the researchers attempt to evaluate a gamified learning experience. The participants were students of a Master in Business Administration course. The students were asked to participate in a gamified module and relevant data was collected, before and after the intervention. Based on a review of literature, the researchers identified the exogenous variables of Valence, Attitude towards use of Technology and Experience with Technology. The endogenous variables identified included Reaction and Learning. The findings of the study suggest that the gamified module resulted in increase in knowledge and that Attitude, Experience and Valence significantly predicted the Learner's reaction to the experience. The findings of the study provide support to key theories in the area of gamification and insights for practitioners, on the factors to be considered before using a gamifiedlearning intervention. 2021 UNIVERSIDADE FEEVALE All rights reserved. -
Review on persistent challenges of perovskite solar cells stability
Today Perovskite solar cell (PSC) has achieved efficiency close to 26%, surpassing the efficiencies of well- known Dye-Sensitized Solar cells (DSSC), CdTe-based solar cells, etc. Ease of preparing perovskite solutions and convenient deposition technique has given them added advantage over other contemporary competitors. This has also made them an economically feasible option. Since the inception of PSCs in 2009, a lot of improvements have been done in various aspects like composition, synthesis technique, fabrication method, and interface study. However, today it is crucial to think about the commercialization of PSCs. In this direction, the stability of PSCs has been a long-standing question. This review focuses on the key aspects of perovskite stability. Challenges posed by environmental factors like moisture, oxygen, temperature, and light are still unanswered. The lead toxicity of PSCs demands a potential substitute of lead with no compromise in their efficiency. The lead-free approach of PSCs and their commercialization has been discussed separately. A suitable emphasis has been given to the encapsulation of solar cells, as we find it a necessary part of the future commercialization process. This review has been addressed with an ideology to provide overall knowledge on the stability issues and challenges concerned with the PSCs, to attract young research community towards this emerging field. 2021 International Solar Energy Society -
Influence of career re-entry enablers on job search outcomes: COVID strengthening the disparity virus?
Women in India when faced with the predicament of managing their homes and work, many a times are forced to take a break from their job. On completion of their personal responsibilities when they contemplate re-entering work, they face numerous hindrances. Covid has only raised additional concerns in their career landscape. In this context based on the social cognitive career theory that adopts human agency perspective we theorize that women are not mere bystanders but themselves contribute to their life outcomes through their self-efficacy and resultant job search efforts. Using the components in the SCCT model (Social cognitive career theory) of career self-management (CSM), data from 385 respondents was analysed using Exploratory Factor Analysis, Confirmatory Factor Analysis and Structure Equation Modeling. The study confirmed the direct and indirect relationship between self-efficacy in job search behaviour, outcome expectations, search goals, search actions and the final job search outcome measured through the number of offers received. Implications of this study to the managers, family and society are also discussed. 2021 Ecological Society of India. All rights reserved. -
Occupational stress: A pre and post COVID-19 perspective on teaching personnel in higher education institutions of India
The COVID-19 as a catalytic phenomenon exposes many loop holes in the socio-economic sustainability of business and society. It exposed people to different occupational stressors and anxiety. This study was focused on occupational stress of teaching personnel in higher education institutions (HEIs), in both pre and post COVID-19 scenario. Descriptive analysis shows work autonomy, career progression, community membership, work conditions, and freedom to use own judgements are major stressors to to HEI teachers in the post COVID-19 scenario. Inferential evaluation has confirmed that Job security, social service, and creativity are major concerns to HEI teachers. They experience limitations to try their own ways of doing job. 2021 Ecological Society of India. All rights reserved. -
Studies on anti-microbial potential of withania somnifera (l.) dunal and future perspectives: An overview
Withania somnifera is a herb of immense ethnopharmacological importance in Ayurvedic, Siddha and Unani systems of medicine. Due to its immense therapeutic potential and being an important source of novel withanolides, it has been a subject of immense intrigue among researchers. Apart from its anti-inflammatory, antitumor, anti-stress, antioxidant, immunomodulatory, antidiabetic, sedative and hemopoetic properties, there is mounting evidence for its antimicrobial and antiviral properties too. Various withanolides and steroidal lactones isolated so far are known to have high therapeutic value, but works pertaining to their antimicrobial potential have largely been at the synergistic level. No single withanolide has been characterized as a sole antimicrobial and thus, work in this regard is still in the stage of infancy, except for withanone which has recently shown in silico activity against SARS-COV-2. This review summarizes the elaborate antibacterial, antifungal, antiprotozoal and anti-viral work that has been done so far and casts focus on the limitations, in terms of mechanistic aspects of each. 2021 Society for Biology and Biotechnology. All rights reserved. -
The odd one is Out: Voices from virtual classrooms
This article is a response to the online classrooms initiated from April 2020 onwards in schools across the country after the declaration of the lockdown. As classes went live in some parts of the country and several schools prepped towards the new medium, voices and experiences emerged from the field to throw light on the odds. The article collects the voices of students, educators and parents largely from the cities of Delhi and Bengaluru. The narratives are to be seen against the background of the critique of auto-modernism and emergent technology-intensive social institutions in the wake of COVID-19. This perspective pieces together the issues of infrastructure inadequacy in technology and the exclusiveness of pedagogy, and charts the inability of the marginalised sections in exercising the fundamental right to education. This article also highlights that internet classrooms are temporary make-shift arrangements. 2021 Economic and Political Weekly. All rights reserved. -
Recent advances in bimetallic based nanostructures: Synthesis and electrochemical sensing applications
Detection of biomolecules is paramount for the diagnosis of various health conditions in humans for improving the quality as well as the standard of living. Many of the existing analytical detection methods being used have one or the other drawbacks. This has led to revolutionary paradigms in research and development in the electrochemical sensing of biomolecules. Nanoparticles have enhanced surface area to volume ratio and are highly effective as sensors due to their improved electrocatalytic properties. Bimetallic nanoparticles such as platinum, nickel, iron, palladium, and gold-based nanoparticles in combination with other metals are being extensively used for electrode modification owing to their unique electrocatalytic characteristics. The synergistic effect of two metals provides us with highly sensitive electrodes. Over a while, there has been a significant increase in research carried out in this field, which encouraged us to carry out a thorough survey of the development of bimetallic nanoparticle-based electrochemical sensors for the sensing of glucose, hydrogen peroxide, ascorbic acid, dopamine, and uric acid. We have also mentioned the different types of electrode modifications for developing electrochemical sensors. This review provides readers a comparative study of the analytical parameters of the various electrochemical sensors for linear range, detection limit, and sensitivity. 2020 Elsevier B.V. -
A critical review of anticancer properties of Withania somnifera (L.) Dunal with respect to the biochemical mechanisms of its phytochemical constituents
Cancer is a leading cause of mortality worldwide, the conventional chemotherapeutic drugs have been known for their toxicity and numerous side effects. A new approach to treat cancer involves phytochemical drugs. In the present review, anti-cancer activity of a class of steroidal lactones called withanolides obtained from Withania somnifera (L.) Dunal is discussed. The commonly studied bioactive compounds namely withaferin-A, withanoside IV, withanoside VI and withanolide-A among others obtained from methanolic and chloroform extract of the leaves and various alcoholic, aqueous and chloroform extract of roots have shown inhibition to various human cancer cell lines including skin, breast, colon, prostate, liver, ovary, cervical and lung. Prominent mechanisms of action include induction of apoptosis by NOS upregulation, ROS production and NBS2 or COX-2 inhibition; cytotoxicity by humoral and cell mediated immune response, activation of p53 and pRB and inhibition of various viral oncoproteins; cell cycle arrest by Cdc2 facilitated mitotic catastrophe, cyclin-D1 down-regulation and inhibition of transcription factors. Cancers are also controlled by inhibition of angiogenesis and metastasis of the tumor cells. In addition to anti-tumorogenic properties, W. somnifera also holds properties that make it a potential adjuvant in integrated cancer therapeutics and in enhancing the effectiveness of ongoing radiation therapy. Surya et al (2021). -
Recent Trends in the Synthesis and Mechanistic Implications of Phenanthridines
Phenanthridine derivatives are one of the most intensively studied families of biologically active compounds. There has been considerable scientific interest in the turn of this century in the synthesis of these N-containing heterocycles as they are prevalent in many alkaloids and also possess striking biological activities including antibacterial, antifungal, antitumor activities. In this regard, a number of synthetic approaches toward the construction of phenanthridine moieties with various substituents, and to increase their yield have been developed by the synthetic organic community. Even though many researchers have developed various innovative methods for the synthesis of phenanthridine derivatives for the past few years, still there is substantial scope for the discovery of novel synthetic methods. In this review, the latest developments in the diverse synthetic strategies of phenanthridine derivatives in the presence and absence of metals were described. The present review also enlightens the use of different reagents, the diversity of the substrates identified, and the plausible mechanisms unravelled towards the construction of these biologically relevant scaffolds. (Figure presented.). 2021 Wiley-VCH GmbH -
Waste elimination to porous carbonaceous materials for the application of electrochemical sensors: Recent developments
World is expected to face a big disaster from waste materials generated as a result of the ever-growing industrialization. Recent developments in the area of biomass-derived materials and valuable products has attracted many into its diverse applications. Biomass-derived porous carbonaceous materials are highly recommended for the development of electrochemical sensors due to their unique features like cost-effectiveness, distinctive structure, sustainability, and regenerative nature. The electrochemical and catalytic activity of the sensor differ based on their surface morphology specifically surface area, pore-volume, and pore size. Various techniques like activation, doping, and dispersion of metal nanoparticles are efficient in enhancing the performance of sensors. Some of the essential or seminal developments in the area of biomass-derived carbonaceous materials for detecting diverse target analytes like pharmaceutical drugs, metal ions, biomolecules, food additives, pollutants, and flavonoids are reviewed. 2020 Elsevier Ltd -
Development and Validation of Work Environment Services Scale (WESS)
Purpose: This study presents a nine-factor, 32-item measure of work environment scale in the service sector. A healthy work environment is one in which employees trust the people they work for, have pride in what they do, and enjoy working with the people (Levering and Moskowitz, 2004). Methodology: This instrument builds on the conceptual model espoused by Insel and Moos (1974), Gordon (1973), Fletcher and Nusbaum (2010), Amabile et al. (1996), and Spector (2003). The scale included items elicited through a literature review, the use of the Delphi technique with a panel of experts, and tested on 824 full-time employees from nine service sector industries and five major cities in India. Findings: The Work Environment Services Scale (WESS) is a reliable and valid scale useful for measuring the nine work environment factors in the Indian services organization, with its own norms and a detailed manual. Originality/Value: The prevailing scales for measuring work environment do not capture the influence of ethics, recreation facilities, and the impact of social giving on the work environment. Most scales were suitable for sectors in the Western context, and there were no Indian scales measuring service employees' perception of their work environment. 2021 Harold Andrew Patrick et al., published by Sciendo 2021. -
Role of polyamines in plant tissue culture: An overview
Since the era of plant tissue culture bloomed, we have started approaching from a biotechnological perspective to overcome the massive challenges like inducing embryogenesis and organogenesis, initiating rooting, increasing the number of plantlets, establishing a callus from various organs of plants and also enhancing the metabolite content which was a mind-boggling thought once upon a time. Use of various elicitors, altering the media components, the strength of media, pH, precursor feeding etc. have all contributed tremendously in the in-vitro techniques used for culturing rare, endemic and medicinal plants for the commercial purposes. Owing to the demand for the plant products and drugs, the search for the other superior novel methods to increase its quantity and quality has not been stopped. Thus, one such method is the use of chemical compounds with many amino groups which serves as an additional source of nitrogen in the media and these organic compounds are called polyamines. Polyamines are known to play a wide role in plant physiological processes helping them in differentiation, inducing totipotency, increasing cell division and also in molecular signaling. Polyamines have a versatile application in this field ranging from establishing a callus to the elicitation of secondary metabolites. Thus, polyamines can be considered as a boon to the plant tissue culture field. In this review article, we have mainly focused on the in-depth applications of major polyamines like putrescine, spermidine and spermine in the field of plant tissue culture. 2021, The Author(s), under exclusive licence to Springer Nature B.V. part of Springer Nature. -
Comparison of streams delineated using various SRTM, ASTER and Cartosat DEM
Results from the study on the comparison of the stream network delineated from Shuttle Radar Topography Mission (SRTM) DEM, Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) DEM and Cartosat DEM with the stream network extracted from Toposheets concluded that SRTM DEM of 30m resolution was correlated well with the stream network extracted from SOI toposheets compared to ASTER and Cartosat DEM. It is recommended to utilise SRTM open access DEM of 30m resolution from research work carried out over the study area. 2021 Ecological Society of India. All rights reserved. -
Crumpled and porous graphene for supercapacitor applications: a short review
Research on Graphene and its importance in the field of energy conversion and storage devices such as fuel cells, batteries, supercapacitors and solar cells has gained momentum recently. It is studied to be the most suitable electrode material for enhanced performance of supercapacitors in terms of chargedischarge cycles, specific capacitance, high power and energy densities and so on, specifically due to its high conductivity and large theoretical surface area. Unfortunately, it posits lot of challenges due to its irreversible stacking between the individual sheets resulting in the decrease in the Specific Surface Area (SSA) compared to the theoretically reported values. Numerous studies have been carried out to prevent this stacking in order to increase the surface area, thereby being a more suitable material for the manufacture of electrodes for supercapacitors as its capacitance greatly depends on the electrode material. To solve this problem, the conversion of two-dimensional graphene sheets to three-dimensional crumpled graphene structure has been verified to be the most effective approach. The study of crumpled graphene has been one of the recent trends in the field of energy storage applications in consumer electronics and hybrid vehicles as the process of crumpling can be controlled to suit the prospective device applications. 2021, Korean Carbon Society. -
Electrochemical efficacies of coal derived nanocarbons
Carbon based nanomaterials are acknowledged for their admirable optical, electrical, mechanical characteristics and broad class of applications. Choice of precursor and simple synthesis techniques have decisive roles in viable production and commercialization of carbon produce. The intense demand to develop high purity carbon nanomaterials through inexpensive techniques has promoted usage of fossil derivatives as feasible source of carbon. Coal serves as a naturally available, abundant and cheap feedstock for carbon materials. From the crystalline clusters of aromatic hydrocarbons in a cross-linked network, carbon nanostructures can easily be extracted through green synthesis routes. It promotes a potent alternative for the cost effective and scaled up production of nanocarbon. The well-developed pores distribution, presence of numerous active sites and appropriate migration channels for ions enhance the electrochemical parameters necessary for the fabrication of supercapacitors, batteries and electrochemical sensors. The metallic impurities contained in coal contribute towards faradic redox reactions required for an efficient electrode modification. In this review, the potential uses of coal based carbon nanomaterials in energy storage and environmental sectors are discussed in detail. 2020, The Author(s). -
Review - Electrochemical Strategies for Selective Fluorination of Organic Compounds
The conventional methods for carrying out fluorination of organic compounds are typically conducted using a pre-modified starting material, usually expensive and toxic reagents. In this regard, electrochemical fluorination has been recognized as a sustainable and scalable strategy. Electrofluorination has proven to be an environmentally benign, highly effective, and versatile platform for the synthesis of selective organofluorine compounds under mild conditions. This review provides an overview on the use of anodic electrochemical methods for vicinal difluorination, iodofluorination, fluoroalkynylation, fluorodecarboxylation, fluoro desulfurization, radiofluorination, and synthesis of fluorinated heterocycles. Modern advances in the field of electrochemical fluorination, such as ionic liquids mediated electrochemical fluorination, triethylammonium halides, mixed non-aqueous solvents, alkali-metal fluoride, and split-bipolar electrodes in the field of electrochemical fluorination are also discussed. 2021 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.