Why and when people share their knowledge has received enough academic attention, while little attention devoted to why and when people hide knowledge at workplace. Drawing on the social exchange ...theory, the norms of reciprocity, and the psychological ownership theory, this study examines how territoriality directly and under the indirect influence of knowledge hiding affect task performance and workplace deviance in organization. The study of 198 triads (ie., the team leader, the team leader's subordinate, and team leader's supervisor) reveals that territoriality and knowledge hiding have negative effect on task performance but positive influence on workplace deviance (ie., interpersonal and organizational deviance). Another contribution of the study is that knowledge hiding negatively mediates the influence of territoriality on task performance and workplace deviance. Implications for theory, practice and future research have been discussed.
•COVID-19 pandemic has sparked a research revolution to understand the disease and find a cure.•The past year has seen rapid advances in understanding the biology of SARS-CoV-2 and developing ...therapeutics.•Four vaccines have recently cleared phase III trials (BNT162b2, AZD1222, Sputnik V, and mRNA-1273 vaccine).•At the pandemic's 1-year mark, we summarize information on SARS-CoV-2 gathered in the past year.
We are living through an unprecedented crisis with the rapid spread of the new coronavirus disease (COVID-19) worldwide within a short time. The timely availability of thousands of SARS-CoV-2 genomes has enabled the scientific community to study the origin, structures, and pathogenesis of the virus. The pandemic has spurred research publication and resulted in an unprecedented number of therapeutic proposals. Because the development of new drugs is time consuming, several strategies, including drug repurposing and repositioning, are being tested to treat patients with COVID-19. Researchers have developed several potential vaccine candidates that have shown promise in phase II and III trials. As of 12 November 2020, 164 candidate vaccines are in preclinical evaluation, and 48 vaccines are in clinical evaluation, of which four have cleared phase III trials (Pfizer/BioNTech's BNT162b2, Moderna's mRNA-1273, University of Oxford & AstraZeneca's AZD1222, and Gamaleya's Sputnik V vaccine). Despite the acquisition of a vast body of scientific information, treatment depends only on the clinical management of the disease through supportive care. At the pandemic's 1-year mark, we summarize current information on SARS-CoV-2 origin and biology, and advances in the development of therapeutics. The updated information presented here provides a comprehensive report on the scientific progress made in the past year in understanding of SARS-CoV-2 biology and therapeutics.
Tumor invasion and metastasis are strongly regulated by biophysical interactions between tumor cells and the extracellular matrix (ECM). While the influence of ECM stiffness on cell migration, ...adhesion, and contractility has been extensively studied in 2D culture, extension of this concept to 3D cultures that more closely resemble tissue has proven challenging, because perturbations that change matrix stiffness often concurrently change cellular confinement. This coupling is particularly problematic given that matrix-imposed steric barriers can regulate invasion speed independent of mechanics. Here we introduce a matrix platform based on microfabrication of channels of defined wall stiffness and geometry that allows independent variation of ECM stiffness and channel width. For a given ECM stiffness, cells confined to narrow channels surprisingly migrate faster than cells in wide channels or on unconstrained 2D surfaces, which we attribute to increased polarization of cell-ECM traction forces. Confinement also enables cells to migrate increasingly rapidly as ECM stiffness rises, in contrast with the biphasic relationship observed on unconfined ECMs. Inhibition of nonmuscle myosin II dissipates this traction polarization and renders the relationship between migration speed and ECM stiffness comparatively insensitive to matrix confinement. We test these hypotheses in silico by devising a multiscale mathematical model that relates cellular force generation to ECM stiffness and geometry, which we show is capable of recapitulating key experimental trends. These studies represent a paradigm for investigating matrix regulation of invasion and demonstrate that matrix confinement alters the relationship between cell migration speed and ECM stiffness.
Lead accumulation in soils is of serious concern in agricultural production due to the harmful effects on soil microflora, crop growth and food safety. In soil, speciation of lead greatly affects its ...bioavailability and thus its toxicity on plants and microbes. Many plants and bacteria have evolved to develop detoxification mechanisms to counter the toxic effect of lead. Factors influencing the lead speciation include soil pH, organic matter, presence of various amendments, clay minerals and presence of organic colloids and iron oxides. Unlike, other metals little is known about the speciation and mobility of lead in soil. This review focuses on the speciation of lead in soil, its mobility, toxicity, uptake and detoxification mechanisms in plants and bacteria and bioremediation strategies for remediation of lead contaminated repositories.
•Lead is one of the major inorganic persistent global pollutant.•Lead forms stable complexes with soil components.•Lead had no biological function and induces toxic effects on soil microflora and plants.•Plants and microbes have various mechanisms in response to lead which can be applied for bioremediation of various lead contaminated sites.
•Green transformational leadership influences green human resource management (GHRM) practices.•Green innovation predicts environmental performance.•Green innovation mediates the influence of GHRM ...practices on environmental performance.
Drawing upon the resource-based view and the ability-motivation-opportunity theory, we examined how green human resource management interplays on to the linkages amongst green transformational leadership, green innovation and environmental performance. Using a survey questionnaire, we collected triadic data from 309 manufacturing sector small and medium-sized enterprises (SMEs). We used covariance-based structural equation modeling (SEM) to examine hypotheses in this study. Results of the study suggest that green HRM practices mediates the influence of green transformational leadership on green innovation. We also found that green HRM indirectly through green innovation influences firm's environmental performance. Overall, the findings of our study support all hypotheses of direct and indirect effects and have several theoretical and practical implications. Finally, our study significantly advances theory and suggests that HRM-performance relationship neither depends upon the additive effect of green transformational leadership and green innovation as antecedent and mediator, respectively, nor on their interactive effect but a mix of both combinational forms (ie., additive and interactive) to affect firm environmental performance. Overall, our study contributes and advances the previous studies wherein in leadership plays critical role to influence the HRM practices and that in turn to predict green innovation in the organization.
The protein kinases regulate cellular functions such as transcription, translation, proliferation, growth and survival by the process of phosphorylation. Over activation of signaling pathways play a ...major role in oncogenesis. The PI3K signaling pathway is dysregulated almost in all cancers due to the amplification, genetic mutation of PI3K gene and the components of the PI3K pathway themselves. Stimulation of the PI3K/Akt/mTOR and Ras/Raf/MEK/ERK pathways enhances growth, survival, and metabolism of cancer cells. Recently, the PI3K/Akt/mTOR and Ras/Raf/MEK/ERK signaling pathways have been identified as promising therapeutic targets for cancer therapy. The kinase inhibitors with enhanced specificity and improved pharmacokinetics have been considered for design and development of anticancer agents. This review focuses primarily on the Ras/Raf/MEK/ERK and PI3K/Akt/mTOR signaling pathways as therapeutic targets of anticancer drugs, their specific and dual inhibitors, structure activity relationships (SARs) and inhibitors under clinical trials.
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•PI3K/Akt/mTOR and Ras/Raf/MEK/ERK signaling pathways have been described.•The pathways inhibitors and their SARs have been described.•The pathways inhibitors under clinical trial have also been described.
The high-molecular-weight glycosaminoglycan, hyaluronic acid (HA), makes up a significant portion of the brain extracellular matrix. Glioblastoma multiforme (GBM), a highly invasive brain tumor, is ...associated with aberrant HA secretion, tissue stiffening, and overexpression of the HA receptor CD44. Here, transcriptomic analysis, engineered materials, and measurements of adhesion, migration, and invasion were used to investigate how HA/CD44 ligation contributes to the mechanosensing and invasive motility of GBM tumor cells, both intrinsically and in the context of Arg-Gly-Asp (RGD) peptide/integrin adhesion. Analysis of transcriptomic data from The Cancer Genome Atlas reveals upregulation of transcripts associated with HA/CD44 adhesion. CD44 suppression in culture reduces cell adhesion to HA on short time scales (0.5-hour postincubation) even if RGD is present, whereas maximal adhesion on longer time scales (3 hours) requires both CD44 and integrins. Moreover, time-lapse imaging demonstrates that cell adhesive structures formed during migration on bare HA matrices are more short lived than cellular protrusions formed on surfaces containing RGD. Interestingly, adhesion and migration speed were dependent on HA hydrogel stiffness, implying that CD44-based signaling is intrinsically mechanosensitive. Finally, CD44 expression paired with an HA-rich microenvironment maximized three-dimensional invasion, whereas CD44 suppression or abundant integrin-based adhesion limited it. These findings demonstrate that CD44 transduces HA-based stiffness cues, temporally precedes integrin-based adhesion maturation, and facilitates invasion.
This study reveals that the CD44 receptor, which is commonly overexpressed in GBM tumors, is critical for cell adhesion, invasion, and mechanosensing of an HA-based matrix.
Reduced graphene oxide (rGO) was synthesized from graphite flakes utilizing improved Hummers method via graphene oxide (GO) precursor. The oxidation of graphite and subsequent reduction of GO were ...confirmed by using FTIR, XRD, Raman spectroscopy and TEM techniques. The nanocomposite adhesives were developed using GO and rGO with different loading of 0–1.0 wt%. The adhesive strength was studied by conducting lap shear test and it was noticed that, Ep-0.5 GO adhesive exhibited the highest strength among all adhesive formulations and showed ∼50% increment than pristine epoxy. Impact strength evidenced noticeable enhancement with decrease in notch depth from 2.54 to 0.5 mm for all adhesive systems clearly indicating brittle to ductile transition due to the declining stress concentration area. The fracture analysis of impact samples and extent of fillers dispersion were visualized by SEM. SEM micrographs evidenced clear surface contrast of samples based on variable notch depth. The electrical resistivity in Ep-rGO systems showed 93% decrease with 1 wt% rGO loading, while thermal conductivity of Ep-0.5 GO revealed 211% increment as compared to pristine epoxy.
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•Synthesis of reduced graphene oxide (rGO) using improved Hummers method.•Superior mechanical properties for Ep-GO adhesives than their rGO counterparts.•Adhesive's impact strength increased with decreasing notch depth from 2.54 to 0.5 mm.•ρ of Ep-rGO systems was superior than Ep-GO systems, while contrary result for Tc.•Tg of all nanocomposite adhesives diminished with inclusion of nanomaterials.
Geopolymerisation of mechanically activated fly ash was studied at ambient (27
°C) and elevated (60
°C) temperatures by isothermal conduction calorimeter. Under both the conditions, mechanical ...activation enhanced the rate and decreased time of reaction. It was interesting to observe that in the samples milled for 45
min (median size ∼5
μm), a broad peak corresponding to geopolymerisation initiated at 27
°C after 32
h. The rate maxima at 60
°C, a measure of fly ash reactivity, showed a non-linear dependence on particle size and increased rapidly when the median size was reduced to less than 5–7
μm. Improvement in strength properties is correlated with median particle size, and reactivity of fly ash. The characterisation of the geopolymer samples by SEM-EDS, XRD and FTIR revealed that mechanical activation leads to microstructure and structural variations which can be invoked to explain the variation in the properties.
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•Biowastes as a resource for producing bioplastics such as polyhydroxyalkanoates (PHAs).•Potential PHAs as nontoxic implants, biocontrol, tissue repair, and drug delivery ...agents.•Strategy for improving soil, delivering biocides, and mulching through PHAs.•Plastic waste management through sustainable technologies.
Plastics are an integral part of most of the daily requirements. Indiscriminate usage and disposal have led to the accumulation of massive quantities of waste. Their non-biodegradable nature makes it increasingly difficult to manage and dispose them. To counter this impending disaster, biodegradable polymers, especially polyhydroxy-alkanoates (PHAs), have been envisaged as potential alternatives. Owing to their unique physicochemical characteristics, PHAs are gaining importance for versatile applications in the agricultural and medical sectors. Applications in the medical sector are more promising because of their commercial viability and sustainability. Despite such potential, their production and commercialization are significant challenges. The major limitations are their poor mechanical strength, production in small quantities, costly feed, and lack of facilities for industrial production. This article provides an overview of the contemporary progress in the field, to attract researchers and stakeholders to further exploit these renewable resources to produce biodegradable plastics on a commercial scale.
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