A Convenient Synthesis of New Annelated Pyrimidines and Their Biological Importance

Several bicyclic/tricyclic‐fused pyrimidines were synthesized from the reactions of amino esters and bifunctional nucleophiles such as 2‐methylthio‐thiazoline and 2‐methylthio‐imidazoline. The synthesized compounds were tested for their in vitro antimicrobial activities that revealed mild to moderate growth inhibitory potentials.     

A Conductive polylactic acid/polyaniline porous scaffold via freeze extraction for potential biomedical applications

This paper reports for the first time a simple yet effective method for fabricating a conductive and highly porous scaffold material made up of polylactic acid (PLA) and conducting polyaniline (PANI). The electrical percolation state was successfully obtained at 3 wt% of PANI inclusions and reached a conductivity level of useable tissue engineering applications at 4 wt%. In addition, preliminary bioactivity test results indicated that the protonating agent could form a chelate at the scaffold surface leading to good in-vitro apatite forming ability during biomimetic immersion. This new conductive scaffold has potential as a suitable biomedical material that requires electrical conductivity.     

Effect of wall compliance on compressible fluid transport induced by a surface acoustic wave in a microchannel

Effects of complaint wall properties on the flow of a Newtonian viscous compressible fluid has been studied when the wave propagating (surface acoustic wave, SAW) along the walls in a confined parallel‐plane microchannel is conducted by considering the slip velocity. A perturbation technique has been employed to analyze the problem where the amplitude ratio (wave amplitude/half width of channel) is chosen as a parameter. In the second order approximation, the net axial velocity is calculated for various values of the fluid parameters and wall parameters. The phenomenon of the “mean flow reversal” is found to exist both at the center and at the boundaries of the channel. The effect of damping force, wall tension, and compressibility parameter on the mean axial velocity and reversal flow has been investigated, also the critical values of the tension are calculated for the pertinent flow parameters. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 27: 621–636, 2011 Keywords:     

Radiation synthesis of acrylic acid/polyethyleneimine interpenetrating polymer networks (IPNs) hydrogels and its application as a carrier of atorvastatin drug for controlling cholesterol

Gamma irradiation was used to form interpenetrating polymer networks structure (IPNs) hydrogels based on different ratios of acrylic acid monomer (AAc) and polyethyleneimine (PEI). The property-behavior was characterized by IR spectroscopy, gel content, thermogravimetric analysis (TGA) and swelling in water at room temperature and different pH values. The AAc/PEI hydrogels were used as a carrier for atorvastatin drug, in which the uptake-release character was studied. The results showed that the gel content of AAc/PEI hydrogels decreased greatly with increasing the ratio of PEI in the initial feeding solution. The AAc/PEI hydrogels displayed pH-sensitive character. The drug uptake-release study indicated that AAc/PEI hydrogels possessed controlled release behavior and that the release process depends on pH. In this respect, the release of atorvastatin drug was significant in acidic medium.     

Nitrate, ascorbic acid, mineral and antioxidant activities of Cosmos caudatus in response to organic and mineral-based fertilizer rates

The source and quantity of nutrients available to plants can affect the quality of leafy herbs. A study was conducted to compare quality of Cosmos caudatus in response to rates of organic and mineral-based fertilizers. Organic based fertilizer GOBI (8% N:8% P?O?:8% K?O) and inorganic fertilizer (15% N, 15% P?O?, 15% K?O) were evaluated based on N element rates at 0, 30, 60, 90, 120 kg h?1. Application of organic based fertilizer reduced nitrate, improved vitamin C, antioxidant activity as well as nitrogen and calcium nutrients content. Antioxidant activity and chlorophyll content were significantly higher with increased fertilizer application. Fertilization appeared to enhance vitamin C content, however for the maximum ascorbic acid content, regardless of fertilizer sources, plants did not require high amounts of fertilizer.     

Synthesis of substituted indoles using continuous flow micro reactors

Continuous flow micro fluidic devices for organic synthesis (‘micro reactors’) are becoming established in a number of facets of modern applied chemistry. As part of a concurrent research project with a pharmaceutical company for generation of materials of pharmaceutical interest within continuous flow environments, we present here, for the first time a series of indoles that have been produced within micro reactor systems. We have developed three different approaches to the synthesis, which are compared with traditional batch synthesis as well as each other in terms of ease of optimization, chemical suitability and versatility, and implications as to throughput. Typical throughputs of approach 1 (simulated classical synthesis) were in the region of 2 mgh⁻¹ of indoles such as tetrahydrocarbazole and cyclopentaindole. The second approach (based on Elk's modification of Fischer indole synthesis) gave throughputs of 5.7-8.9 mgh⁻¹ and the final approach (using heterocatalytic flow reactors) gave the highest throughputs of 12.7-20.1 mgh⁻¹. All throughputs are per single channel reactor system (i.e., one single reactor set up), and the latter two approaches produce viable output quantities for the syntheses of radiolabelled materials (where typically minute amounts of high purity materials are required from a rapid and safe production environment).     

Low temperature X-ray diffraction study of CdI2 crystals

Solid state structural transformations in polytypic crystals of cadmium iodide have been investigated at low temperatures using X-ray diffraction techniques. The crystals were cooled to liquid nitrogen and liquid helium temperatures employing three different methods. The results obtained are discussed on the basis of bond dissociation energies of interlayer and intralayer bonds and the possible mode of layer displacements in MX₂-type polytypic crystals.     

Self-assembling of chain molecules in low dimensions: A Monte Carlo study

We studied the self-assembling of linear chain molecules in insoluble monolayers due to attractive interactions. We used lattice Monte Carlo simulations in a two-dimensional system. The molecules consist of segments occupying adjacent lattice sites. The head segments are confined to move along a line whereas the chain segments can arrange in a plane above the heads. Only one interaction parameter is applied. At high densities and small interaction energy the system shows percolation behavior. At moderate and small densities it can be characterized by a monotonous cluster size distribution. Self-assembling occurs at small densities for strong attractive interactions. The corresponding cluster size distributions indicate preferred cluster sizes which depend upon density and interaction strength. With increasing density the clusters grow. The internal cluster structure depends on the cluster size and the interaction parameter. The clusters tend to minimize their total energy. Molecules at cluster margins contribute less to the cluster energy and are mainly disordered. They cause that the cluster properties strongly depend on the cluster size. Large clusters only have minimum energy if the molecules in the cluster are in stretched-out conformation. With decreasing interaction strength the clusters get disordered thereby producing less energy-minimized domain boundaries.     

A Comparative Study of Existing Polytype Notations with Reference to the CdI2 Polytypes

Existing polytype notations have been critically examined to select a single notation which can describe the CdI₂ structures completely and most conveniently. A comparative study shows that the Zhdanov notation fulfils both the conditions. However, the ambiguities in the similar looking symbols is removed by employing some simple criteria proposed by Jain and Trigunayat for deciding the equivalent structures. Further, being numerical in nature this is the easiest notation to handle.