Determination of methyl gallate in Bauhinia retusa extract by high-performance liquid and thin-layer chromatography

Two stability-indicating chromatographic methods are reported for the determination of methyl gallate in crude extracts of Bauhinia retusa. Separation by high performance thin layer chromatography was conducted on silica gel aluminum sheets using 9.5:0.5:0.2 (v/v/v) chloroform:methanol:acetic acid at 280 nm. The results from the 2–40 µg/band were used to prepare a linear calibration graph. The limits of detection and quantitation were 0.5 and 1.5 µg/band, respectively. The reverse phase high performance liquid chromatographic isolation of methyl gallate was performed at ambient temperature with an injection volume of 10 μL. The mobile phase consisted of 40:60 (v/v) methanol:0.1% ortho-phosphoric acid. The separation was performed at 1 mL/min using a detection wavelength of 280 nm. The calibration graph for methyl gallate was rectilinear from 0.02–40 µg/mL with limits of detection and quantitation of 0.004 and 0.010 µg/mL, respectively. For both methods, intra-day and inter-day precision were evaluated and the relative standard deviation was less than 2%, indicating good precision. The robustness was evaluated by making small and deliberate changes to appropriate parameters and the calculated relative standard deviation was less than 2%.The chromatographic methods were employed to determine methyl gallate in crude Bauhinia retusa extracts.     

Grafting of vinyl acetate onto chitosan and biocidal activity of the graft copolymers

The reaction process of polycarbosilane (PCS) fiber cured by cyclohexene vapor has been studied and compared with that of PCS fiber cured by air. The influence of curing temperature on Si? H bond reaction degree and gel content, the structure and composition of PCS were investigated by FTIR, EA, TGA, NMR, and GC‐MS. The results showed that, Si? H bond in the molecular structure of PCS reacted during cyclohexene curing process and the reaction degree increased when the curing temperature increases. Simultaneously, gel content of PCS fiber rapidly increased till PCS fiber became infusible. Si? H radical and Si? CH₂ radicals formed Si? CH₂? Si crosslinking of PCS molecules through the agency of cyclohexene. Some cyclohexyls linked to principal chain of PCS, which was proven by ¹³C‐CPMAS‐NMR, and broke off, and cyclohexane and some monosilane are generated as byproducts when temperature increased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

The finite-element deformation modeling of superplastic Al-8090

The deformation behaviors of an Al-Li-Cu alloy (Aluminum 8090) during uniaxial and biaxial stress states were modeled using the nonlinear finite element analysis package ABAQUS 5.8. Two different material models were used for the purpose of comparison and to propose a valid and accurate superplastic material deformation behavior. Using a power law strain hardening model, the material was modeled with either constant or variable properties of strain-rate sensitivity and strain-hardening exponent. Results from the numerical models were compared to experimental results by Chen and Huang, who investigated the uniaxial and biaxial states of stress. Experimental data were primarily used to acquire the needed uniaxial material parameters for the model. The strain-rate sensitivity and strain-hardening exponent were dependent on the strain and strain rates. Comparing the two material models for both stress states indicated that the material model with variable properties better represented the true behavior of the material when compared to the experimental results. For more information, contact Noha M. Hassan, the American University in Cairo, 113 Kasr El Aini St., P.O. Box 2511, Cairo 11511, Egypt; +202-797-5336; fax +202-797-7565; e-mail nhassan@vt.edu.     

Issues in the training of school psychologists in program evaluation.

Program evaluation is becoming increasingly important to all professional psychologists, including school psychologists. Despite a burgeoning of information about program evaluation principles, little attention has been given to program evaluation training, especially the utility of that training for program decision making. Five issues pertinent to the training of school psychologists in program evaluation are discussed: need for training, extent of training, goals of training, methods of training, and evaluation of training experiences. The material presented is based on the authors' experiences in program evaluation training at the Rutgers School Psychology Training Program. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The traditional and emerging role of nuts in healthful diets

Throughout history, nuts have been a staple food providing energy, protein, essential fatty acids, vitamins, and minerals. Today, nuts are classified as part of the USDA Food Guide Pyramid's Meat/ Meat Alternate Group. Foods in this group contribute protein as well as important vitamins and minerals to the diet. Nuts are also being studied for their potential health benefits. Research suggests that there may be a connection between frequent nut consumption and a reduced incidence of coronary heart disease. Thus, tradition and promising scientific evidence combine to support the role of nuts in healthful eating.     

Molecular genetic diagnosis of von Hippel-Lindau disease in familial phaeochromocytoma

Inherited predisposition to phaeochromocytoma is seen in multiple endocrine neoplasia type 2 syndromes, von Hippel-Lindau (VHL) disease, and neuro-fibromatosis type 1. In addition familial phaeochromocytoma alone has been reported. To investigate the genetic basis for familial phaeochromocytoma alone, we screened three affected kindreds for mutations in the RET proto-oncogene and the VHL tumour suppressor gene. We did not detect MEN 2 associated RET mutations in any family, but missense VHL gene mutations (V155L and R238W) were identified in two kindreds with no clinical evidence of VHL disease. Patients with familial, multiple, or early onset phaeochromocytoma should be investigated for germline VHL and RET gene mutations as the molecular diagnosis of multisystem familial cancer syndromes enables appropriate counselling and screening to be provided.     

Energy balance for a DC plasma torch

A study was made of the energy utilization efficiency in a d.c. plasma toich operating with argon at atmospheric pressure at a power level of 10-25 kW. Calorimetric measurements of the energy lost to the cathode, anode and that remaining in the plasma jet showed that the torch efficiency was about 40 to 50%. It increases with an increase of the plasma gas flow rate but decreases with an increase of the current intensity. The electrode spacing was found to have no significant influence on the efficiency over the range investigated. The torch efficiency could be substantially improved by a reduction of the anode size. The addition of small concentrations of a diatomic gas such as nitrogen improved the efficiency to about 65% and increased the total power dissipated in the torch.