Stable and reproducible synthesis of gold nanorods for biomedical applications: a comprehensive study

Gold nanorods (GNRs) are ideal choice in biomedical research due to their amenability of synthesis, tunable plasmonic properties, less toxicity and ease of detection but their diverse biological applications necessitate stable structure. Despite two decades'' efforts made towards reproducible anisotropic structures synthesis, still the kinetic control during GNRs growth has not been achieved. This study is an attempt to apprehend thermodynamic and kinetic parameters for synthesising mono‐disperse, reproducible and highly stable GNRs with desired aspect ratios. Effects of various growth parameters and assay steps on the facile and reproducible synthesis of GNRs are analysed. GNRs'' environmental and biological colloidal stability is studied through UV–Vis spectroscopy based particle instability parameter (PIP < 0.1). The authors hereby report GNRs with tunable longitudinal surface plasmon resonance (682–906 nm) having different aspect ratios (2.5–4.6) that are stable at 28–60°C; however, prolonged high temperature ( > 60°C) and alkaline pH can trigger colloidal instability. GNRs remain stable at higher salt concentration, physiological and slightly acidic pH. GNRs can be stored in 0.001 M cetyltrimethylammonium bromide for 3 months without compromising their stability. PEGylated GNRs are quite stable in cellular media solution (PIP < 0.1). With current optimised growth conditions, no aggregation at physiological pH and stability at high temperatures make GNRs an ideal candidate in biomedical applications.Inspec keywords: gold, nanorods, nanofabrication, nanomedicine, toxicology, thermodynamics, ultraviolet spectra, visible spectra, surface plasmon resonance, pH, cellular biophysicsOther keywords: nanorod synthesis, biomedical applications, tunable plasmonic properties, toxicity, reproducible anisotropic structures synthesis, thermodynamic parameters, kinetic parameters, GNR, biological colloidal stability, UV‐Vis spectroscopy, particle instability parameter, tunable longitudinal surface plasmon resonance, aspect ratios, alkaline pH, physiological pH, slightly acidic pH, cetyltrimethylammonium bromide, cellular media solution, optimised growth conditions, aggregation, wavelength 682 nm to 906 nm, time 3 month, Au     

Spin State of Cobalt and Electrical Transport Mechanism in MgCo<Subscript>2</Subscript>O<Subscript>4</Subscript> System

MgCo₂O₄ samples were synthesized by inverse co-precipitation method. The formation of a single-phase spinel structure was confirmed by X-ray diffraction measurements and Fourier-transform infrared spectroscopy. The samples crystallized in a face-centered cubic structure with Fd-3m space group as revealed from the Rietveld refinement of X-ray diffraction data. Magnetic measurements carried out in a broad temperature range of 5–300 K showed antiferromagnetic to paramagnetic phase transition (Neel temperature) observed at 101 K. Magnetic susceptibility data fitted using the Curie Weiss law and effective Bohr magnetic moment (μ_eff) for Co atoms was determined. Calculated μ_eff comes out to be 3.05 μ_B. These results were correlated to the spin states of Co³⁺ atoms. A small hysteresis in the field-dependent magnetization MH loop taken at 5 K indicates the existence of weak ferromagnetism in this system. The electrical resistivity measurement in the temperature range 77–750 K displayed the semiconducting-like behavior for this system.     

Analyzing COVID-19 Impact on the Researchers Productivity through Their Perceptions

Context: Since the end of 2019, the COVID-19 pandemic had a worst impact on world’s economy, healthcare, and education. There are several aspects where the impact of COVID-19 could be visualized. Among these, one aspect is the productivity of researcher, which plays a significant role in the success of an organization. Problem: There are several factors that could be aligned with the researcher’s productivity of each domain and whose analysis through researcher’s feedback could be beneficial for decision makers in terms of their decision making and implementation of mitigation plans for the success of an organization. Method: We perform an empirical study to investigate the substantial impact of COVID-19 on the productivity of researchers by analyzing the relevant factors through their perceptions. Our study aims to find out the impact of COVID-19 on the researcher’s productivity that are working in different fields. In this study, we conduct a questionnaire-based analysis, which included feedback of 152 researchers of certain domains. These researchers are currently involved in different research activities. Subsequently, we perform a statistical analysis to analyze the collected responses and report the findings. Findings: The results indicate the substantial impact of COVID-19 pandemics on the researcher’s productivity in terms of mental disturbance, lack of regular meetings, and field visits for the collection of primary data. Conclusion: Finally, it is concluded that researcher’s daily or weekly meetings with their supervisors and colleagues are necessary to keep them more productive in task completion. These findings would help the decision makers of an organization in the settlement of their plan for the success of an organization.     

Towards Novel Treatments for Schizophrenia: Molecular and Behavioural Signatures of the Psychotropic Agent SEP-363856

Schizophrenia is a complex psychopathology whose treatment is still challenging. Given the limitations of existing antipsychotics, there is urgent need for novel drugs with fewer side effects. SEP-363856 (SEP-856) is a novel psychotropic agent currently under phase III clinical investigation for schizophrenia treatment. In this study, we investigated the ability of an acute oral SEP-856 administration to modulate the functional activity of specific brain regions at basal levels and under glutamatergic or dopaminergic-perturbed conditions in adult rats. We found that immediate-early genes (IEGs) expression was strongly upregulated in the prefrontal cortex and, to a less extent, in the ventral hippocampus, suggesting an activation of these regions. Furthermore, SEP-856 was effective in preventing the hyperactivity induced by an acute injection of phencyclidine (PCP), but not of d-amphetamine (AMPH). The compound effectively normalized the PCP-induced increase in IEGs expression in the PFC at all doses tested, whereas only the highest dose determined the major modulations on AMPH-induced changes. Lastly, SEP-856 acute administration corrected the cognitive deficits produced by subchronic PCP administration. Taken together, our data provide further insights on SEP-856, suggesting that modulation of the PFC may represent an important mechanism for the functional and behavioural activity of this novel compound.     

Determination of convective heat transfer for fenestration with between-the-glass louvered shades

In previous work, a two-dimensional steady laminar natural convection model of a window cavity with between-panes louvers (i.e., slats) was developed by approximating the system as a vertical cavity with isothermal walls at different temperatures, and with rotatable baffles located midway between the walls. The baffles were set to a third temperature so that night-time and day-time conditions, and the effects of low emissivity coatings (low-e), could be considered. It was found that the system is suited to a traditional one-dimensional analysis. A novel approach that allows the use of standard vertical cavity convection correlations and a modified cavity half-width is described, and a cavity modification factor, n^*, is presented. Finally, the n^* factor and vertical cavity convection correlation are joined with a longwave radiant model, and the results are compared to experimental results. The models show good agreement with experiments.     

Hot Dates

For this article, an analytical study has been conducted on the flow and energy transfer of unsteady compressible oscillating flow through channels filled with porous medium representing stack in thermoacoustic engines/refrigerators. The flow in the porous material is described by the Darcy momentum equation. Analytical expressions for oscillating velocity, temperature in the porous layer, complex Nusselt number, and energy flux density are obtained after simplifying and solving the governing differential equations with reasonable approximations (such as long wave, short stack, small amplitude oscillation, etc.). The result for heat transfer between the porous medium and the channel wall is expressed as a dimensionless Nusselt number. For the limiting case of nonporous medium, the Nusselt number obtained in the present study matches quantitatively with the expression available in the existing literature. The results reveal that the Nusselt number in oscillating flow is significantly enhanced (almost an order of magnitude) by employing sufficiently large thermal conductivity of porous media in a channel. The system of equations developed in the present study is a helpful tool for thermal engineers to design porous stacks for thermoacoustic devices.     

In vivo the antioxidative extract of Averrhoa carambola Linn. leaves induced apoptosis in Ehrilch ascites carcinoma by modulating p53 expression

Food Science and Biotechnology - This study was designed to evaluate the antioxidant activity of methanol extract of Averrhoa carambolla Linn. leaves (MELA) using DPPH· and ABTS·+ free...