Genetic variation at the beta-fibrinogen locus in relation to plasma fibrinogen concentrations and risk of myocardial infarction. The ECTIM Study

Increased plasma fibrinogen concentration is a major cardiovascular risk factor. Conflicting results on genetic variations in plasma fibrinogen levels have been reported. Furthermore, whether fibrinogen genotype is associated with the risk of ischemic heart disease has not been studied so far. An HaeIII restriction fragment length polymorphism of the beta-fibrinogen gene was used in a case-control study to investigate the genetic variation at this locus in relation to plasma fibrinogen concentrations and the risk of myocardial infarction (MI). Five hundred thirty-three male patients aged 27-66 years and 648 control subjects were recruited from four World Health Organization MONICA centers in Northern Ireland and in France. The absence of the HaeIII cutting site (H2 allele) was associated with a significant rise in fibrinogen concentrations in both patients and control subjects. The effect of the HaeIII polymorphism on plasma fibrinogen levels did not significantly differ between centers. Fibrinogen levels were higher in smokers than in nonsmokers. The difference between the two groups was larger in subjects with the genotype H2H2 than in those with either genotype H1H1 or H1H2, regardless of the case-control status. However, there was no significant interaction between smoking status and genotype in their effects on variance in fibrinogen levels, whereas fibrinogen levels. HaeIII genotype accounted for approximately 1% of the total variance in fibrinogen levels, whereas smoking and age together explained 7% and 5% in control subjects and patients, respectively. The frequency of the H2 allele was 0.21 in control subjects and 0.19 in patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Solubility of chemical warfare agent simulants in supercritical carbon dioxide: experiments and modeling

Solubility data are reported for ethyl phenyl sulfide (EPS) and 2-chloroethyl ethyl sulfide (CEES) in CO₂ at temperatures from 25 to 100 °C. These two sulfide-based compounds are homomorphs for chemical warfare agents (CWAs). Both sulfide–CO₂ mixtures exhibit type-I phase behavior. The maximum in the 100 °C isotherm is approximately 2600 psia for the CEES–CO₂ system and approximately 3400 psia for the EPS–CO₂ system. The Peng–Robinson equation of state (PREOS) is used to model both sulfide–CO₂ mixtures as well as the phase behavior of the 2-chloroethyl methyl sulfide (CEMS)–CO₂ system previously reported in the literature. The Joback–Lydersen group contribution method is used to estimate the critical temperature, critical pressure, and acentric factor for the sulfides. Semi-quantitative estimates of the phase behavior are obtained for the CEES–CO₂ and EPS–CO₂ systems with a constant value of k_ij, the binary interaction parameter, fit to the 75 °C isotherms. However, very poor fits are obtained for the 2-chloroethyl methyl sulfide–CO₂ system regardless of the value of k_ij. On the basis of the high solubility of EPS and CEES in CO₂, supercritical fluid (SCF)-based technology could be used to recycle or recover chemical warfare materials.     

Static output feedback stabilization with H/sub /spl infin// performance for linear discrete-time systems

This note presents a new sufficient condition for the static output feedback stabilization of linear discrete-time systems. This new condition is expressed as a linear matrix inequality feasibility problem and hence easily tractable numerically. An extension of this condition is given in order to incorporate H/sub /spl infin// performance objectives. The applicability of the proposed approach is shown through numerical examples and compared to some recent methods.     

Queue size distribution in a discrete-time D-BMAP/G/1 retrial queue

We consider a discrete-time batch Markovian arrival process (D-BMAP)/G/1 retrial queue. We find the light-tailed asymptotics for the stationary distributions of the number of customers at embedded epochs and at arbitrary time. Using these tail asymptotics we propose a method for calculating the stationary distributions of the number of customers at embedded epochs and at arbitrary time. Numerical examples are presented to illustrate our results.     

Hydrodynamics in a gravity settling vessel: CFD modelling with LDA validation

Vertical gravity settling vessels, usually referred to as primary separation vessels (PSV), are used in separating bitumen aggregates from slurry containing sand and fine clays. The hydrodynamics in the PSV influences the separation efficiency of recovered bitumen through the overall mean flow and turbulent interaction. In order to deepen our understanding of the hydrodynamic conditions in such vessels, this paper presents a combined study of the flow field using Laser Doppler Anemometry (LDA) to measure the velocity field, and computational fluid dynamics (CFD) simulations to validate the CFD model. The investigation shows that the flow geometry has a significant influence on the overall flow pattern in such vessels. It also demonstrates that the CFD simulation is a reliable tool in capturing the complex mean flow pattern observed in experiments. Use of different turbulent models such as the standard k‐ε model and Reynolds stress model has very little effect on the mean flow field.     

Photovoltaic marketing in developing countries

Photovoltaic (PV) insolation-harnessing is acknowledged as the most practical economic solution to meet the requirements of one hundred million people without electricity in the developing countries. Industrialized countries in particular, have been active in utilizing such technologies because they can afford the current peak watt prices of US $3–15 for such systems. The market in those countries will soon be close to saturation and attention by suppliers will have to be shifted to the already established larger market in less developed countries (LDCs). PV marketing in these developing countries, i.e. ability to penetrate the potential market, is facing tremendous hurdles. This paper reviews the present status and future directions of the PV market in developing countries as well as discusses the current technical, social, financial or geopolitical barriers and constraints, which are making this market difficult at present. Possible policy frameworks are also proposed which are in line with the trends in the world. The paper concludes by making a global policy package proposal, in terms of an appeal on the global community concerned with PV to propagate this proposal more convincingly, perhaps to emanate from an internationally recognized “forum”, like a PV conference and exhibition, with cooperation and participation of PV manufacturers, suppliers, industrialized countries, NGOs, financial institutions and developing countries.     

Thermal Analysis on the Pyrolysis of Tetrabromobisphenol A and Electric Arc Furnace Dust Mixtures

The pyrolysis of Tetrabromobisphenol A (TBBPA) mixed with electric arc furnace dust (EAFD) was studied using thermogravimetric analysis (TGA) and theoretically analyzed using thermodynamic equilibrium calculations. Mixtures of both materials with varying TBBPA loads (1:1 and 1:3) were prepared and pyrolyzed in a nitrogen atmosphere under dynamic heating conditions at heating rates of 5 and 10 °C/min. The mixtures degraded through several steps, including decomposition of TBBPA yielding mainly HBr, bromination of metal oxides, followed by their evaporation in the sequence of CuBr₃, ZnBr₂, PbBr₂, FeBr₂, MnBr₂, KBr, NaBr, CaBr₂, and MgBr₂, and finally reduction of the remaining metal oxides by the char formed from decomposition of TBBPA. Thermodynamic calculations suggest the possibility of selective bromination of zinc and lead followed by their evaporation, leaving iron in its oxide form, while the char formed may serve as a reduction agent for iron oxides into metallic iron. However, at higher TBBPA volumes, iron bromide forms, which can also be evaporated at a temperature higher than those of ZnBr₂ and PbBr₂. Results from this work provide practical insight into selective recovery of valuable metals from EAFD while at the same time recycling the hazardous bromine content in TBBPA.