Stretching a Curved Surface in a Viscous Fluid

This work is concerned with the viscous flow due to a curved stretching sheet. The similarity solution of the problem is obtained numerically by a shooting method using the Runge-Kutta algorithm. The physical quantities of interest like the fluid velocity and skin friction coefficient are obtained and discussed under the influence of dimensionless curvature. It is evident from the results that dimensionless curvature causes an increase in boundary layer thickness and a decrease in the skin friction coefficient.     

A Highly Regioselective Iodoenoletherification of α-Allyl-β-ketoesters. A Convenient Route to 2-Alkyl-5-iodomethyl-3-methoxycarbonyl-4, 5-Dihydrofurans

A variety of α-allyl-β-ketoesters (1) containing two different double bonds, undergo highly regioselective iodoenoletherification to give the titled compound (2) in excellent yields.     

An Efficient Synthesis of Silyl Dienol Ethers from α, β-Unsaturated Aldehydes and Ketones

α, β-Unsaturated aldehydes and Ketones when reacted with NaBr-Me₃SiCl-Et₃N in DMF at ambient temperature, yield silyl dienol ethers in high yields.     

Biofabrication of iron oxide nanoparticles by leaf extract of Rhamnus virgata: Characterization and evaluation of cytotoxic,antimicrobial and antioxidant potentials

In the present study, plant‐mediated synthesis of iron oxide nanoparticles (IONPs) using leaves extract of Rhamnus virgata (Roxb.) as a potential stabilizing, reducing and chelating agent is reported. The biogenic IONPs are extensively characterized for their physical and biological properties. The morphology, structure and physicochemical properties of biogenic IONPs were characterized using ultraviolet spectroscopy, X‐ray diffraction, Fourier transform‐infrared analysis, scanning electron microscopy, energy‐dispersive spectroscopy, transmission electron microscopy, Raman spectroscopy and dynamic light scattering. The Scherrer equation deduced a mean crystallite size of ~20 nm for IONPs. Detailed in vitro biological activities revealed significant therapeutic potentials for IONPs. Potential antibacterial and antifungal activities are reported for IONPs. Bioinspired IONPs have shown potential results against HepG2 cells (IC₅₀: 13.47 μg/ml). Dose‐dependent cytotoxicity assays were revealed against Leishmania tropica (KMH₂₃) promastigotes (IC₅₀: 8.08 μg/ml) and amastigotes (IC₅₀: 20.82 μg/ml) using different concentrations of IONPs (1–200 μg/ml). The cytotoxic activity was also studied using brine shrimps, and their IC₅₀ value was calculated as 32.41 μg/ml. Significant antioxidant [TAC (51.4%), DPPH (79.4%) and total reducing power (62%)], protein kinase and alpha amylase inhibition assays were revealed. The biocompatibility assays using red blood cells (> 200 μg/ml) and macrophages (> 200 μg/ml) confirmed the biosafe nature of IONPs. In conclusion, bioinspired IONPs have shown potential biological applications and should be subjected to further research work to develop their nano‐pharmacological relevance in biomedical applications.     

Stability-Indicating High-Performance Thin-Layer Chromatographic Method for the Simultaneous Determination of Quercetin and Resveratrol in the Lipid-Based Nanoformulation

JPC – Journal of Planar Chromatography – Modern TLC - A simple, sensitive, specific, rapid, and accurate high-performance thin-layer chromatographic (HPTLC) method has been developed...     

High-yield synthesis of pure ZnO nanoparticles by one-step solid-state reaction approach for enhanced photocatalytic activity

Zinc oxide (ZnO) nanostructures were synthesized via a one-step solid-state reaction approach in ammonia (NH₃) gas environment with different temperature ramp rates. The so-formed nanostructures were characterized using X-ray diffraction (XRD) for phase identification, where the typical wurtzite hexagonal structure was observed. Scanning electron microscopy (SEM) confirmed the particle size to be in the range 45–50 nm, the same as calculated by the XRD pattern for the ramp rate of 10 °C/min. Energy dispersive X-ray (EDX) spectroscopy and X-ray photoelectron spectroscopy (XPS) confirmed the chemical purity of the samples. The photoluminescence (PL) spectrum indicated multiple near-band-edge emissions and energy-band emissions. Then, these ZnO nanomaterials were used for the degradation of crystal violet (CV) dye under UV light irradiation. The CV solution was completely degraded in 2 hr. The initial photocatalyst and dye amounts of 0.2 g/100 ml and 0.5 mg/L, respectively, were found to be the optimum values for maximum degradation efficiency. The ZnO-based photocatalyst was stable up to three cycles of reuse. These results indicate that the high surface area and porosity of the nanomaterials are responsible for the high efficiency, which was confirmed by specific surface area analysis.     

Aqueous Synthesis of Triphenylphosphine-Modified Gold Nanoparticles for Synergistic In Vitro and In Vivo Photothermal Chemotherapy

Triphenylphosphine (TPP) surface-functionalized and F-108 Pluronic-stabilized gold nanoparticles (F-108@TPP-AuNPs) have been synthesized through a one-step approach, leading to well-defined (9.6±1.6 nm) and water-soluble nanoparticles by microwave heating an aqueous solution of TPP-Au^ICl in the presence of a Pluronic polymer under basic conditions. TPP release was negligible under physiological conditions, but enhanced significantly at an acidic pH (5.4) mimicking that of a cancer cell. Laser irradiation (532 nm) raised the temperature of an aqueous solution of F-108@TPP-AuNPs to 51.7 °C within 5 min, confirming efficient light-to-heat conversion capabilities without significant photodegradation. TEM confirmed intracellular localization of F-108@TPP-AuNPs in the cytosol, endosomes and lysosomes of HeLa cells. F-108@TPP-AuNPs were well tolerated by HeLa cells and zebrafish embryos at ambient temperatures and became toxic upon heat activation, suggesting synergistic interactions between heat and cytotoxic action by TPP.     

Stereoselective synthesis of the C1-C10 fragment of rhizoxin D

A novel approach towards the synthesis of the C1-C10 fragment of the biologically active antimitotic agent rhizoxin D is described. The synthesis involves a stereoselective Michael addition reaction of lithium diallyl cuprate with an α,β-unsaturated six membered lactone.     

One‐Pot Synthesis of Redox‐Responsive Polymers‐Coated Mesoporous Silica Nanoparticles and Their Controlled Drug Release

A versatile one‐pot strategy for the preparation of reversibly cross‐linked polymer‐coated mesoporous silica nanoparticles (MSNs) via surface reversible addition–fragmentation chain transfer (RAFT) polymerization is presented for the first time in this paper. The less reactive monomer oligo(ethylene glycol) acrylate (OEGA) and the more reactive cross‐linker N,N′‐cystaminebismethacrylamide (CBMA) are chosen to be copolymerized on the external surfaces of RAFT agent‐functionalized MSNs to form the cross‐linked polymer shells. Owing to the reversible cleavage and restoration of disulfide bonds via reduction/oxidation reactions, the polymer shells can control the on/off switching of the nanopores and regulate the drug loading and release. The redox‐responsive release of doxorubicin (DOX) from this drug carrier is realized. The protein adsorption, in vitro cytotoxicity assays, and endocytosis studies demonstrate that this biocompatible vehicle is a potential candidate for delivering drugs. It is expected that this versatile grafting strategy may help fabricate satisfying MSN‐based drug delivery systems for clinical application.

     

Mixed aggregate formation in gemini surfactant/1,2-dialkyl-sn-glycero-3-phosphoethanolamine systems

An evaluation of the physical interactions between gemini surfactants, DNA, and 1,2-dialkyl-sn-glycero-3-phosphoethanolamine helper lipid is presented in this work. Complexation between gemini surfactants and DNA was first investigated using surface tensiometry where the surface tension profiles obtained were found to be consistent with those typically observed for mixed surfactant-polymer systems; that is, there is a synergistic lowering of the surface tension, followed by a first (CAC) and second (CMC) break point in the plot. The surfactant alkyl tail length was observed to exhibit a significant effect on the CAC, thus demonstrating the importance of hydrophobic interactions during complexation between gemini surfactants and DNA. The second study presented is an investigation of the mixing interactions between gemini surfactants and DOPE using Clint's, Rubingh's, and Motomura's theories for mixed micellar formation. The mixing interactions between the 16-3-16/16-7-16/16-12-16/16-7NH-16 gemini surfactants and DOPE were observed to be antagonistic, where the strength of antagonism was found to be dependent upon the gemini surfactant spacer group and the solution composition.