Effect of intracoronary estrogen on coronary collateral blood flow velocity

The effect of estrogen on collateral circulation has not been previously investigated. We assessed the acute effect of estradiol on collateral blood flow velocity with the Flowire during percutaneous transluminal coronary angioplasty and found that intracoronary estradiol decreased collateral blood flow velocity compared with controls.     

Adventitial expression of recombinant eNOS gene restores NO production in arteries without endothelium

The current study was designed to determine the effect of recombinant endothelial nitric oxide synthase (eNOS) gene expression on endothelium-dependent relaxations to bradykinin in isolated canine basilar, coronary, or femoral arteries. Arterial rings were exposed ex vivo (30 minutes at 37 degrees C) to an adenoviral vector encoding either the eNOS gene (AdCMVeNOS) or the beta-galactosidase reporter gene (AdCMVbeta-Gal). Twenty-four hours after transduction, transgene expression was evident mainly in the adventitia. Expression of recombinant proteins was much higher in basilar arteries than in coronary or femoral arteries. Rings of control, AdCMVbeta-Gal, and AdCMVeNOS arteries with and without endothelium were suspended for isometric tension recording. Levels of cGMP were measured by radioimmunoassay. In AdCMVeNOS basilar arteries with endothelium, relaxations to low concentrations of bradykinin (3 x 10(-11) to 10(-9) mol/L) were significantly augmented. In contrast, in coronary and femoral arteries with endothelium, AdCMVeNOS transduction did not affect relaxations to bradykinin. Removal of the endothelium abolished bradykinin-induced relaxations in control and AdCMVbeta-Gal basilar arteries. However, in basilar arteries transduced with AdCMVeNOS even when the endothelium was removed, stimulation with bradykinin (3 x 10(-11) to 10(-9) mol/L) caused relaxations as well as increases in cGMP production. The relaxations to bradykinin were completely blocked by an NOS inhibitor, NG-nitro-L-arginine methyl ester. Electron microscopic analysis revealed that recombinant eNOS protein was expressed in fibroblasts of the basilar artery adventitia. These results suggest that genetically modified adventitial fibroblasts may restore production of NO in cerebral arteries without endothelium. Our findings support a novel concept in vascular biology that fibroblasts in the adventitia may play a role in the regulation of vascular tone after successful transfer and expression of recombinant eNOS gene.     

Use of elimination of plasma phospholipid membranes for detection of "lupus anticoagulant" effects

The coagulation activity of plasma phospholipid membranes (PM) was measured in plasma depleted for platelets (PDP) in 50 normal subjects and 33 patients with the antiphospholipid syndrome (APS) and the "lupus anticoagulant" in the plasma. The normal value for phospholipid activation of clotting was 99.8 +/- 3.5% (from 75 to 125%), whereas in patients with APS and lupus anticoagulant it was 42.1 +/- 8.2% (p < 0.001). Addition of PM from patients' PDP to normal plasma free from PM did not normalize clotting. Addition of PM from normal plasma to patients' PDP normalized the clotting time. Therapy with discrete plasmapheresis increased the phospholipid activation value in the patients from 42.1 to 73.3% (p < 0.01), which was due to removal of the PM-antiphospholipid antibody complex from PDP. The proposed microfiltration method can be used in the complex of tests for detecting the lupus anticoagulant in patient's plasma.     

Electrochemical preparation and characterization of poly(1-amino-9,10-anthraquinone) films

Poly(1-amino-9,10-anthraquinone), PAAQ, films were prepared by electrochemical oxidation of the monomer, AAQ, in acetonitrile using LiClO₄ as supporting electrolyte. The influence of scan repetition, scan rate and monomer concentration on the formation of polymer film was studied. The electrochemical behavior of the formed polymer films was investigated in both non-aqueous and aqueous media. The prepared films were found to be more stable in organic solvents than in aqueous solutions. The investigated organic solvents are methanol, ethanol, acetone, carbon tetrachloride, benzene, and chloroform. The polymer film shows electrochemical response in both non-aqueous and aqueous media. In non-aqueous solutions it has a wide potential range of electroactivity (from −1.5 to +1.3 V). In aqueous media the polymer film shows electrochemical response in the potential range between −0.3 and +1.3 V only. The presence of quinone units suggests potential applications in diverse areas such as electrocatalytic processes and lithium ion batteries.     

Monitoring and modelling of variables affecting isomerate octane number produced from an industrial isomerization process

Petroleum refineries are now facing much tighter and stricter transportation and fuel specification standards, as well as environmental regulations, than in previous years. Therefore, tough rules have been applied on gasoline specifications. Octane number is a key variable of gasoline quality. Isomerization is one of many processes that generate profit by increasing low gasoline octane numbers, with better environmental impacts compared to other processes. Here we analyzed and optimized the various variables affecting the isomerate octane numbers produced by isomerization. Feed composition (naphthenes and benzene content in the feed) and operating conditions (temperature, hydrogen consumption and liquid hourly space velocity) data were collected from the Midor isomerization plant (Egypt) over a 4-year period based on the catalyst lifetime. These data were then used to predict the influence of feed composition and operating conditions on isomerate research octane number using a Response Surface Methodology (RSM) approach (Design Expert software). Thus, we were able to predict isomerate research octane number under various operating conditions. All of the studied variables were found to influence octane number.     

Range image segmentation using local approximation of scan lines with application to CAD model acquisition

Abstract. Automatic acquisition of CAD models from existing objects requires accurate extraction of geometric and topological information from the input data. This paper presents a range image segmentation method based on local approximation of scan lines. The method employs edge models that are capable of detecting noise pixels as well as position and orientation discontinuities of varying strengths. Region-based techniques are then used to achieve a complete segmentation. Finally, a geometric representation of the scene, in the form of a surface CAD model, is produced. Experimental results on a large number of real range images acquired by different range sensors demonstrate the efficiency and robustness of the method. Received: 1 August 2000 / Accepted: 23 January 2002 Correspondence to: I. Khalifa     

New concepts of extrusion dies to reduce the anisotropy of extruded profiles by means of additive manufacturing

The directionality of material flow in established forming processes often leads to a material-specific development of anisotropic mechanical properties. The significance is determined by the process related state variables. A new approach to control the state variables and to reduce the mechanical anisotropy is based on an extrusion die design concept where material flow components perpendicular to the extrusion direction (ED) are adjusted. Specially shaped internal free-form surfaces require additive manufacturing for the establishment of the dies. A concept for a flat band profile is elaborated and the impact on exemplary lightweight alloys, aluminum alloy AA6060 and magnesium alloy AZ31 is discussed.     

An advanced ANN model for predicting the rotational behaviour of semi-rigid composite joints in fire using the back-propagation paradigm

This paper describes an artificial neural networking (ANN) model developed to predict the behaviour of semi-rigid composite joints at elevated temperature. Three different semi-rigid composite joints were selected, two flexible end-plates and one flush end-plate. Seventeen different parameters were selected as input parameters representing the geometrical and mechanical properties of the joints as well as the joint’s temperature and the applied loading, and used to model the rotational capacity of the joints with increasing temperatures. Data from experimental fire tests were used for training and testing the ANN model. Results from nine experimental fire tests were evaluated with a total of 280 experimental cases. The results showed that the R² value for the training and testing sets were 0.998 and 0.97, respectively. This indicates that results from the ANN model compared well with the experimental results demonstrating the capability of the ANN simulation techniques in predicting the behaviour of semi-rigid composite joints in fire. The described model can be modified to study other important parameters that can have considerable effect on the behaviour of joints at elevated temperatures such as temperature gradient, axial restraints, etc.     

Sintering of Bahariya Iron Ore Using Anthracite at the Egyptian Iron & Steel Company

Metallurgist - The partial and complete replacement of coke breeze with anthracite for sintering Bahariya iron ore at the Egyptian Iron &amp; Steel Company (EISCO) was carried out. The best...