Spray drying of drug-swellable dispersant suspensions for preparation of fast-dissolving,high drug-loaded,surfactant-free nanocomposites

Bioavailability of a poorly soluble drug can be improved by preparing a drug nanosuspension and subsequently drying it into nanocomposite microparticles (NCMPs). Unfortunately, drug nanoparticles aggregate during milling and drying, causing incomplete recovery and slow dissolution. The aim of this study is to investigate the impact of various classes of dispersants on drug dissolution from drug NCMPs, with the ultimate goal of enhancing the bioavailability of poorly water-soluble drugs via high drug nanoparticle loaded, surfactant-free NCMPs. Precursor suspensions of griseofulvin (GF, model drug) nanoparticles in the presence of various dispersants were prepared via wet stirred media milling and spray dried to form the NCMPs. Hydroxypropyl cellulose (HPC, polymer) alone and with sodium dodecyl sulfate (SDS, surfactant) was used as a base-line stabilizer/dispersant during milling. Two swellable crosslinked polymers, croscarmellose sodium (CCS) and sodium starch glycolate (SSG), and a conventional soluble matrix former, Mannitol, were used in addition to HPC. Besides being used as-received, CCS was also wet co-milled with GF for two different durations to examine the impact of CCS particle size. Laser diffraction, scanning electron microscopy, powder X-ray diffraction (XRD), UV spectroscopy, NCMP redispersion and dissolution tests were used for characterization. The results show that incorporation of CCS/SSG, preferably wet-milled to a wide particle size distribution, into the spray-dried NCMPs resulted in fast release and dispersion of drug nanoparticle clusters. The swellable dispersants were superior to Mannitol in dissolution enhancement, and could achieve fast release comparable to SDS, demonstrating the feasibility of spray drying to prepare high drug-loaded, surfactant-free nanocomposites.     

Recovery of deuterium from hydrogen–deuterium mixture using palladium

The applicability of palladium for the separation of hydrogen isotopes (hydrogen and deuterium) is evaluated systematically by generating isotherm data and conducting column experiments in a laboratory set-up. Effect of various parameters such as concentration of the isotopic mixture, particle size, eluent flow rate, etc. is studied experimentally. A fixed-bed chromatographic model is developed and validated using the experimental data. The model is further used to predict the performance of a multi-column configuration for large-scale separation. Chromatographic separation is thus found to be a promising technique to achieve the required purity and hence it may be clubbed with the existing systems (e.g. cryogenic distillation) to obtain enhanced performance.     

Electrical and Dielectric Properties of Non-magnetic Al<Superscript>3+</Superscript> Substituted Ni–Zn Nano Ferrites for High Frequency Applications

The effect of Al substitution on electrical and dielectric parameters of Ni–Zn ferrite has been discussed in the present work. The phase identification, surface morphology was studied using X-ray diffractometer (XRD), scanning electron microscope (SEM), respectively. The XRD patterns confirm the single-phase formation of these ferrites. With Al³⁺, substitution lattice parameter decreases due to smaller Al³⁺ ions replacing Fe³⁺ ions. The average grain size obtained from SEM results are in the range of 390–27 nm. The DC resistivity was observed to increase with increasing Al³⁺ ions concentration due to the unavailability of Fe³⁺ ions. Dielectric constant (\(\upvarepsilon ^{\prime }\)) and dielectric loss tangent (tan δ) have been studied as a function of frequency (1 kHz–10 MHz) and temperature (50–300 °C). The observed results are explained on the basis of interfacial polarization as predicted by Maxwell and Wagner.     

Experimental Investigation on the Performance of a Solar Still Using SiO2 Nanoparticles /Jatropha curcas L

Silicon - Now, enticing systematic civic since everywhere the world is used in green synthesis and benefit of the simple is eco-friendly with an emergent method of producing nanoparticles (NPs)....     

Facilitating GL13K Peptide Grafting on Polyetheretherketone via 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide: Surface Properties and Antibacterial Activity

In the present work, the antimicrobial peptide (AMP) of GL13K was successfully coated onto a polyetheretherketone (PEEK) substrate to investigate its antibacterial activities against Staphylococcus aureus (S. aureus) bacteria. To improve the coating efficiency, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) was mixed with a GL13K solution and coated on the PEEK surface for comparison. Both energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) data confirmed 30% greater peptide coating on PEEK/GL13K-EDC than PEEK without EDC treatment. The GL13K graft levels are depicted in the micrograms per square centimeter range. The PEEK/GL13K-EDC sample showed a smoother and lower roughness (Rq of 0.530 µm) than the PEEK/GL13K (0.634 µm) and PEEK (0.697 µm) samples. The surface of the PEEK/GL13K-EDC was more hydrophilic (with a water contact angle of 24°) than the PEEK/GL13K (40°) and pure PEEK (89°) samples. The pure PEEK disc did not exhibit any inhibition zone against S. aureus. After peptide coating, the samples demonstrated significant zones of inhibition: 28 mm and 25 mm for the PEEK/GL13K-EDC and PEEK/GL13K samples, respectively. The bacteria-challenged PEEK sample showed numerous bacteria clusters, whereas PEEK/GL13K contained a little bacteria and PEEK/GL13K-EDC had no bacterial attachment. The results confirm that the GL13K peptide coating was able to induce antibacterial and biofilm-inhibitory effects. To the best of our knowledge, this is the first report of successful GL13K peptide grafting on a PEEK substrate via EDC coupling. The present work illustrates a facile and promising coating technique for a polymeric surface to provide bactericidal activity and biofilm resistance to medical implantable devices.     

Correction to: Optimization of Parameters for Maximum Tensile Strength of Friction Stir Welded AA6082/Si3N4 and AA6082/SiC Composite Joints

Silicon - The original version of this paper was unfortunately published with an error in the order of authors and their corresponding affiliations. The correct data is shown above.     

Differential Physio-Biochemical and Metabolic Responses of Peanut (Arachis hypogaea L.) under Multiple Abiotic Stress Conditions

The frequency and severity of extreme climatic conditions such as drought, salinity, cold, and heat are increasing due to climate change. Moreover, in the field, plants are affected by multiple abiotic stresses simultaneously or sequentially. Thus, it is imperative to compare the effects of stress combinations on crop plants relative to individual stresses. This study investigated the differential regulation of physio-biochemical and metabolomics parameters in peanut (Arachis hypogaea L.) under individual (salt, drought, cold, and heat) and combined stress treatments using multivariate correlation analysis. The results showed that combined heat, salt, and drought stress compounds the stress effect of individual stresses. Combined stresses that included heat had the highest electrolyte leakage and lowest relative water content. Lipid peroxidation and chlorophyll contents did not significantly change under combined stresses. Biochemical parameters, such as free amino acids, polyphenol, starch, and sugars, significantly changed under combined stresses compared to individual stresses. Free amino acids increased under combined stresses that included heat; starch, sugars, and polyphenols increased under combined stresses that included drought; proline concentration increased under combined stresses that included salt. Metabolomics data that were obtained under different individual and combined stresses can be used to identify molecular phenotypes that are involved in the acclimation response of plants under changing abiotic stress conditions. Peanut metabolomics identified 160 metabolites, including amino acids, sugars, sugar alcohols, organic acids, fatty acids, sugar acids, and other organic compounds. Pathway enrichment analysis revealed that abiotic stresses significantly affected amino acid, amino sugar, and sugar metabolism. The stress treatments affected the metabolites that were associated with the tricarboxylic acid (TCA) and urea cycles and associated amino acid biosynthesis pathway intermediates. Principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA), and heatmap analysis identified potential marker metabolites (pinitol, malic acid, and xylopyranose) that were associated with abiotic stress combinations, which could be used in breeding efforts to develop peanut cultivars that are resilient to climate change. The study will also facilitate researchers to explore different stress indicators to identify resistant cultivars for future crop improvement programs.     

Immobilization of cholesterol oxidase and potassium ferricyanide on dodecylbenzene sulfonate ion‐doped polypyrrole film

Dodecylbenzene sulfonate (DBS)‐doped polypyrrole (PPY) conducting polymer films were electrochemically deposited onto the indium‐tin‐oxide (ITO)‐coated glass plates in aqueous medium. The enzyme cholesterol oxidase (ChOx) was immobilized on these DBS–PPY films by a physical adsorption technique. These ChOx‐immobilized DBS–PPY films were characterized by ultraviolet–visible and Fourier transform infrared spectroscopy. The enzyme activity studies indicate that ～40% of ChOx leaches out from the ChOx/DBS–PPY film. The ChOx activity in the ChOx/DBS–PPY film was assayed as a function of cholesterol concentration. The results of amperometric measurements conducted on ChOx/DBS–PPY/ITO film show linearity over the range 2–8 mM of cholesterol solution. The ChOx/DBS–PPY/ITO electrodes exhibit a response time of 30 s and are stable for ～3 months at 4 °C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3486–3491, 2001     

Comparative analysis of a Sisko nanofluid over a stretching cylinder through a porous medium

The present article examines the Sisko nanofluid flow and heat transfer through a porous medium due to a stretching cylinder using Buongiorno's model for nanofluids. Suitable similarity transformations are used to transform the governing boundary layer equations of fluid flow into nonlinear ordinary differential equations. The finite difference method is used to solve coupled nonlinear differential equations with MATLAB software. The impact of different parameters viz., the Sisko material parameter, porosity parameter, curvature parameter, thermophoresis parameter, and Brownian diffusion parameter on the velocity and temperature distribution are presented graphically. Moreover, the effect of the involved parameters on the heat transfer rate is also studied and presented through table values. It is noticed from the numerical values that the porosity parameter reduces the velocity while enhancing the temperature. The curvature parameter enhances the velocity throughout the fluid regime and reduces the temperature near the surface while enhancing the temperature far away from the surface. The study reveals that the thermophoresis and Brownian diffusion parameters that characterize the nanofluid flow reduce the wall heat transfer rate, while the curvature parameter enhances it. This investigation of wall heating/cooling has essential applications in solar porous water absorber systems, chemical engineering, metallurgy, material processing, and so forth.