Pharmacological Mechanisms Underlying Gastroprotective Activities of the Fractions Obtained from Polygonum minus in Sprague Dawley Rats

The leaves of Polygonum minus were fractionated using an eluting solvent to evaluate the pharmacological mechanisms underlying the anti-ulcerogenic activity of P. minus. Different P. minus fractions were obtained and evaluated for their ulcer preventing capabilities using the ethanol induction method. In this study, Sprague Dawley rats weighing 150-200 g were used. Different parameters were estimated to identify the active fraction underlying the mechanism of the gastroprotective action of P. minus: the gastric mucus barrier, as well as superoxide dismutase, total hexosamine, and prostaglandin synthesis. Amongst the five fractions from the ethanolic extract of P. minus, the ethyl acetate:methanol 1:1 v/v fraction (F2) significantly (p < 0.005) exhibited better inhibition of ulcer lesions in a dose-dependent manner. In addition, rats pre-treated with F2 showed a significant elevation in superoxide dismutase (SOD), hexosamine and PGE2 levels in the stomach wall mucosa in a dose-dependent matter. Based on these results, the ethyl acetate:methanol 1:1 v/v fraction was considered to be the best fraction for mucous protection in the ethanol induction model. The mechanisms underlying this protection were attributed to the synthesis of antioxidants and PGE2.     

Experimental study of melting ice cylinders in a warm air cross-flow

An experimental study is reported which investigates the melting of ice cylinders transverse to a warm humid flow, under controlled conditions in an air-conditioned wind tunnel. This work was initiated prior to a more general study of warm air defrosting of a complete heat pump evaporator. Tests were conducted with air at various temperatures, relative humidities and velocities. Similarly, the temperature of the core tube, on which the ice cylinders were mounted, was varied by alteration of the water-glycol mixture flowing through it. Two diameters of ice cylinder, 20 and 27 mm, were used. For core temperatures below the melting point of ice, the melting rate was shown to be a strong function of air humidity and temperature. With the core temperature above 0°C, the melting process was dominated by this factor so that air conditions were relatively unimportant.     

A critical investigation of some of the procedures employed in the surgical use of titanium

Rigorous and exhaustive procedures are employed when titanium (Ti) is surgically implanted, whether for orthopaedic or dental applications. Many of these are adopted because it is thought that surface cleanliness is paramount for clinical success. This paper critically examines the necessity for some of these procedures, concentrating on the surface chemistry of Ti plates. Radio frequency plasma treatments are used to remove contamination from as received Ti plates; XPS and ToF-SIMS were used to monitor the effects of surface chemistry. Ti plates are contaminated by immersing them in BSA or by deliberate contamination with the endospores of Bacillus stearothermophilus ATCC 7953. The effectiveness of simple cleaning procedures to remove BSA/Bacillus stearothermophilus are investigated. Attention is given to both the surface cleanliness and sterility after cleaning.This paper was accepted for publication after the 1995 Conference of the European Society of Biomaterials, Oporto, Portugal, 10–13 September.     

A novel technique to minimise energy and pollution in the dyeing of linen fabric

Garments made from linen fabrics have a natural feel and drape. Most commercially available direct and reactive dyes have only a moderate affinity for this cellulosic fibre, although this lack of affinity can be overcome by the use of electrolytes. As a result, high volumes of wastewater containing large amounts of chemicals are discharged from the typical cellulosic material dyehouse. The ‘no‐salt dyeing’ of linen fabric with reactive and direct dyes was achieved by treating linen fabrics with chitosan in a microwave oven. After using the novel dye method, no observed enhancement of either wash or light fastness properties was seen. Dyebath reuse for both reactive and direct dyes was carried out in order to reduce the environmental impact of the dyes. This dyeing method was then applied to dyeing linen fabrics, with each of the items of clothing subjected to layout and cutting according to the design’s patterns; the dyeing results are discussed in this paper.     

Silicon nanomembranes for fingertip electronics

We describe the use of semiconductor nanomaterials, advanced fabrication methods and unusual device designs for a class of electronics capable of integration onto the inner and outer surfaces of thin, elastomeric sheets in closed-tube geometries, specially formed for mounting on the fingertips. Multifunctional systems of this type allow electrotactile stimulation with electrode arrays multiplexed using silicon nanomembrane (Si NM) diodes, high-sensitivity strain monitoring with Si NM gauges, and tactile sensing with elastomeric capacitors. Analytical calculations and finite element modeling of the mechanics quantitatively capture the key behaviors during fabrication/assembly, mounting and use. The results provide design guidelines that highlight the importance of the NM geometry in achieving the required mechanical properties. This type of technology could be used in applications ranging from human-machine interfaces to 'instrumented' surgical gloves and many others.     

Causal models for road accident fatalities in Yemen.

An identification of the causes of road accident fatalities is becoming more important with the growth of technology, population, number of vehicles and the need for their use. Many authors have addressed the problem in the past but no universal findings have been obtained. The problem tends to be different under different environments and for different geographical regions. The aim of this paper is to develop a model for the analysis and forecasting of road accident fatalities in Yemen considering data restrictions. The proposed data has a particular structure of accident occurrence that has not been reported in any existing research using data in other countries. The available data for the period 1978-1995 is used to build models to understand the nature and extent of the causes of fatalities. Part of the data is used for model building and part of it for test purposes. The issues of correlation and causality have been addressed and multiple collinearity is investigated and dealt with. Two alternative models are proposed based on both statistical grounds and that of practicality in viable decision making. The influence of consuming a locally grown stimulant called Qat on road users has been addressed and it is found that it increases the risk of accidents. This is not the common understanding within the authorities in Yemen as growing and consuming Qat is unregulated.