Some polishing experiments on copper in a hyperbolic cell

Some polishing experiments have been carried out on copper anodes in a hyperbolic cell designed by Gilmont and Walton, using orthophosphoric acid as the electrolyte. The results obtained have been compared to those obtained in similar experiments in a Hull cell. It has been found that very similar bands of different reflectivity and polishes are found to form in both the cells. These bands shift with time and a study of such displacements has been made. The results are briefly discussed.     

Biocompatibility of gold nanoparticles and their endocytotic fate inside the cellular compartment: a microscopic overview

Macrophages are one of the principal immune effector cells that play essential roles as secretory, phagocytic, and antigen-presenting cells in the immune system. In this study, we address the issue of cytotoxicity and immunogenic effects of gold nanoparticles on RAW264.7 macrophage cells. The cytotoxicity of gold nanoparticles has been correlated with a detailed study of their endocytotic uptake using various microscopy tools such as atomic force microscopy (AFM), confocal-laser-scanning microscopy (CFLSM), and transmission electron microscopy (TEM). Our findings suggest that Au(0) nanoparticles are not cytotoxic, reduce the production of reactive oxygen and nitrite species, and do not elicit secretion of proinflammatory cytokines TNF-alpha and IL1-beta, making them suitable candidates for nanomedicine. AFM measurements suggest that gold nanoparticles are internalized inside the cell via a mechanism involving pinocytosis, while CFLSM and TEM studies indicate their internalization in lysosomal bodies arranged in perinuclear fashion. Our studies thus underline the noncytotoxic, nonimmunogenic, and biocompatible properties of gold nanoparticles with the potential for application in nanoimmunology, nanomedicine, and nanobiotechnology.     

An Improved System for the Aqueous Lipshutz–Negishi Cross‐Coupling of Alkyl Halides with Aryl Electrophiles

The development of a palladacyclic precatalyst supported by a new biaryl(dialkyl)phosphine ligand (VPhos) in combination with octanoic acid/sodium octanoate as a simple and effective surfactant system provided an improved catalyst system for the rapid construction of a broad spectrum of alkylated scaffolds from alkyl zinc reagents generated in situ.     

Size effect study in magnetoelectric BiFeO3 system

In this paper, we report for the first time finite size effects on Néel temperature (T _N) of magnetoelectric BiFeO₃ system. Novel wet chemical route has been developed to produce fine particles of BiFeO₃ with controlled size and size distribution. Unlike other oxide systems, lattice volume contraction has been observed with decrease in particle size. The decrease in T _N is co-related to unit cell volume contraction occurring with reduction in particle size.     

A stereocontrolled synthesis of (+)-saxitoxin

A concise stereoselective total synthesis of (+)-saxitoxin is described. A silver(I)-initiated hydroamination cascade constructs the bicyclic guanidinium ion core from a alkynyl bisguanidine. This sequence creates two C-N bonds, one C-O bond, and three rings and forms a single stereoisomer in a single synthetic transformation. This process enabled us to complete the synthesis of (+)-saxitoxin in 14 steps from N-Boc-l-serine methyl ester.     

Synthesis,characterization, and application of novel biodegradable self-assembled 2-(N-phthalimido) ethyl-palmitate nanoparticles for cancer therapy

We report the synthesis of novel biodegradable nanoparticles (NPs) which can kill the cancer cells without any additional drug loading. The NP was a self-assembled form of a phthalimide based conjugate, in which the phthalimide moiety was responsible for the anticancer activity. We describe the synthesis of a novel 2-(N-phthalimido) ethyl palmitate (PHEP-Pal) conjugate and subsequent preparation of NPs by a simple self assembly process. The successful synthesis of conjugate was confirmed by various characterization studies including nuclear magnetic resonance spectroscope, Fourier transform infrared spectroscope, TOF-liquid chromatography mass spectroscope, differential scanning calorimetry, and X-ray diffraction unit. The synthesis, shape, size, and size distribution of PHEP-Pal NPs were determined by transmission electron microscope, atomic force microscope, and dynamic light scattering technique. Finally, cell culture studies using A549 and HeLa cells were done to evaluate the anticancer effect of PHEP-Pal NPs, which demonstrated the potency of these NPs for use in cancer chemotherapy.     

Cryopreservation of chick islets

The avian endocrine pancreas shares some similarities with those of mammals. Previously we have reported a technique of isolation of B islets from chick pancreas and also demonstrated their possible use for hypoglycemic drug screening as efficiently as mammalian islets. Here we describe a novel cryopreservative medium for the cryopreservation of chick islets. Isolated chick islets were suspended in a cryo medium consisting of Dulbecco's modified Minimum Essential Medium: Ham's F12 (1:1), Fetal Bovine Serum (20%), Dimethylsulfoxide (10%) with different concentrations (50 microg/ml to 500 microg/ml) of riboflavin or nicotinamide. The viability of revived islets after three and half months was checked by trypan blue dye exclusion and functionality was assessed by insulin secretion in response to glucose challenge. The maximum recovery of viable islets and insulin secretion was obtained in response to glucose challenge at 250 microg/ml concentration of Riboflavin or Nicotinamide. This is a first report on cryopreservation of chick islets exhibiting cryoprotective role of water soluble vitamins without vitamin C.     

In situ synthesis of water dispersible bovine serum albumin capped gold and silver nanoparticles and their cytocompatibility studies

A simple and convenient one step room temperature method is described for the synthesis of bovine serum albumin (BSA) capped gold and silver nanoparticles. BSA reduces silver ions to silver nanoparticles but does not directly reduce gold ions to gold nanoparticles at room temperature and varying pH conditions. However, when silver and gold ions are simultaneously added to BSA, silver ions get reduced to metallic silver first and these in turn reduce gold ions to gold nanoparticles through a galvanic exchange reaction. The so synthesized silver and gold nanoparticles are easily water dispersible and can withstand addition of salt even at high concentrations. It is shown that the capped protein retains its secondary structure and the helicity to a large extent on the nanoparticles surface and that the protein capping makes the nanoparticles cytocompatible.     

Polarisation and polishing studies on copper in a Hull cell

In continuation of our previous work,^1–2 the effects of polishing time, sp. gr. of the electrolyte, addition of EDTA, electrolyte level, etc., on the position, size and shape of the variously polished bands obtained in a Hull cell have now been studied. I–V measurement when carried out showed that total cell voltage increases regularly with total cell current, thereby affording no explanation for the variously polished bands. However, with a specially designed probe electrode,³ it has been possible to study the current distribution as existing during polarisation at different points of the anode surface and thus offer some explanation for the appearance of variously polished bands which could not be interpreted earlier in terms of electrode potentials.