Kinetics of silver nanoparticle growth in aqueous polymer solutions: 1st Nano Update

In this paper we report the effect of poly(vinyl alcohol) (PVA) on the silver nanoparticles formation of different morphologies by using silver nitrate and citric acid as the oxidant and reductant, respectively, for the first time. Our transmission electron microscopy (TEM) results suggest that the presence of PVA has significant impact on the size, shape, and the size distribution of the silver nanoparticles. The reaction follows a zero-order kinetics in [citric acid] as well as in [silver(I)] in the absence and presence of PVA. It was found that PVA and cetyltrimethylammonium bromide (CTAB) concentrations show no significant effects on the rate of CTAB-stabilized silver nanoparticles formation, whereas in presence of PVA, the reaction rate increases with (CTAB). Both spectrophotometric and TEM measurement demonstrated that the orange silver sol consists of aggregates, whereas the purple sol does not contain the aggregated arrangement. On the basis of various observations, the most plausible mechanism has been envisaged.     

Employing lactams for the unprecedented enantiopure synthesis of non-natural amino acid derivatives

The enantiopure non-natural amino acids¹ have been synthesized by insitu generation of iminium and iminium triflates from lactams using triflic anhydride in pyridine buffered media. These molecules with remote chiral centers may be useful in synthesis of natural product particularly Kopsia derived alkaloids.     

Applying a new method for analyzing experimental data on nuclear reactions at high energies

A new statistical method is proposed for the analysis of experimental data obtained in nucleus-nucleus collisions at high energies which borrows from ideas developed using the Random Matrix Theory. The method allows us to detect regions with correlation effects in the momentum distributions of secondary particles.     

Two New Octulosonic Acid Derivatives and a New Cyclohexanecarboxylic Acid Derivative from Erigeron bonariensis L.

The AcOEt‐soluble part of a MeOH extract from the whole plant of Erigeron bonariensis yielded two new rare‐class octulosonic acid derivatives, rel‐methyl (1R,2S,3S,5R)‐3‐(trans‐caffeoyloxy)‐7‐[(trans‐caffeoyloxy)methyl]‐2‐hydroxy‐6,8‐dioxabicyclo[3.2.1]octane‐5‐carboxylate ( 1 ) and 5,8‐di[O‐trans‐caffeoyl]‐3‐deoxy‐β‐D ‐gluco‐oct‐2‐ulopyranosonosyl 4,8‐di[O‐trans‐caffeoyl]‐3‐deoxy‐β‐D ‐gluco‐oct‐2‐ulopyranosidonic acid ( 2 ) along with a cyclohexanecarboxylic acid derivative, (1α,3β,4β,5β)‐1,4‐di‐3,5‐dihydroxy‐bis(trans‐caffeoyloxy)cyclohexanecarboxylic acid ( 3 ). The structures of these compounds were elucidated through ESI‐MS, and 1D‐ and 2D‐NMR spectroscopic techniques including ¹H‐ and ¹³C‐NMR, HMQC or HSQC, and HMBC experiments.     

Standardization of Biomarkers Gallic Acid and Berberine in Polyherbal Formulation Entoban Capsules by High-Performance Thin-Layer Chromatography—Densitometry

JPC – Journal of Planar Chromatography – Modern TLC - The technological improvement in the structural elucidation of natural compounds has made it probable to generate appropriate...     

Metallogels Self‐Assembled from Linear Rod‐Like Platinum Complexes: Influence of the Linkage

Two linear rod‐like platinum complexes, which only differed in the linkage, were prepared. They both self‐assemble into metallogels in nonpolar solvents; however, a very big contrast was observed. Unexpectedly, a much weaker gel was acquired upon replacing the ester linkage by an amide group. The intermolecular hydrogen bonding offered by the amide motif leads to a different stacking fashion and mechanism. The results demonstrated herein contribute to the rational design of metallogels as well as other functional supramolecular materials.     

Automatic Debye–Scherrer elliptical ring extraction via a computer vision approach

The accurate calibration of powder diffraction data acquired from area detectors using calibration standards is a crucial step in the data reduction process to attain high‐quality one‐dimensional patterns. A novel algorithm has been developed for extracting Debye–Scherrer rings automatically using an approach based on computer vision and pattern recognition techniques. The presented technique requires no human intervention and, unlike previous approaches, makes no restrictive assumptions on the diffraction setup and/or rings. It can detect complete rings as well as portions of them, and works on several types of diffraction images with various degrees of ring graininess, textured diffraction patterns and detector tilt with respect to the incoming beam.