Theoretical model for flash generation

Reduction of flash generated in a gas vent is of great concern for manufacturers of electronic parts. The present study proposes a theoretical model for flash generation through consideration of flow characteristics in a gas vent. The model predicts the factors controlling flash, i.e., material parameters such as zero‐shear viscosity, crystallization temperature, thermal conductivity, and heat capacity, and process parameters such as injection and mold wall temperatures, packing pressure, and the clearance of a gas vent. On the other hand, we measure the amount of flash generated in the molding of poly(phenylene sulfide) (PPS) composites containing glass fiber and spherical fillers (CaCO₃ or Al₂O₃). Flash reduces with decreasing size of spherical fillers. These experimental data are successfully interpreted using the flash model. Polym. Eng. Sci., 45:198–206, 2005. © 2005 Society of Plastics Engineers     

Novel electro-optic properties of epitaxially grown (Pb, La)(Zr, Ti)O3 (PLZT) thin films derived by advanced sol–gel methods

Advanced sol–gel methods using a secondary solvent addition into (Pb, La)(Zr, Ti)O₃ (PLZT) sol–gel solution and a methanol pre-treatment of sapphire substrates are demonstrated. For the secondary solvent addition, the additive affected the crystallinity and electro-optic (EO) property of PLZT films and only methanol addition can improve them. In addition, the methanol pre-treatment is also appeared to be effective to improve film characteristics.

Through these optimizations, epitaxially grown PLZT thin films on r-cut sapphire are obtained and a high Pockels coefficient which is comparable to those of bulk PLZTs is achieved. It is believed that these PLZT thin films are applicable for integrated EO devices and open the door for the future data communication systems.     

Polarization-controlled single-mode VCSEL

Relative intensity noise (RIN) in a vertical-cavity surface-emitting laser (VCSEL) was greatly reduced through the use of polarization control to eliminate competition between two orthogonal polarization states by ensuring there was only one polarization state. Polarization was stable with optical feedback of up to 10%. Polarization control was achieved by inducing a small loss anisotropy in fundamental transversal mode VCSEL's. Anisotropic post structures, such as a rectangular post, an oblique post, or a zigzag-sidewall post, were found to be effective in creating loss anisotropy without serious degradation of other VCSEL characteristics such as light-output power or beam profile     

Inhibition of angiotensin-converting enzyme increases the nitric oxide levels in canine ischemic myocardium

Since angiotensin-converting enzyme (ACE) produces angiotensin II in the heart, ACE inhibitors may prevent coronary vasoconstriction and increase coronary blood flow. On the other hand, since ACE inhibitors also inhibit kininase II which results in reduced degradation of bradykinin, ACE inhibitors may increase cardiac nitric oxide (NO) levels via stimulation of bradykinin receptors. This study was undertaken to test whether ACE inhibitors increase the cardiac NO levels and coronary blood flow in the ischemic myocardium. In 34 open-chest dogs, the left anterior descending coronary artery was perfused through an extracorporeal bypass tube from the left carotid artery. When either imidaprilat or cilazaprilat of 3 microg/kg/min was infused into the bypass tube for 10 min after reduction of coronary blood flow due to partial occlusion of the bypass tube, coronary blood flow increased from 31 +/- 1 to either 45 +/- 5 or 43 +/- 4 ml/100 g/min despite no changes in coronary perfusion pressure (43 +/- 2 mmHg). During an infusion of either imidaprilat or cilazaprilat, bradykinin and the end-products of NO (nitrate + nitrite) concentrations of coronary venous blood were markedly increased, which were attenuated by either HOE-140 (an inhibitor of bradykinin receptors) or by N(omega)-nitro-L-arginine methyl ester (an inhibitor of NO synthase). We also observed increases in cardiac bradykinin and NO levels due to either imidaprilat or cilazaprilat in the low constant coronary blood flow condition. It is concluded that ACE inhibitors can increase cardiac NO levels via the accumulation of bradykinin in the ischemic myocardium.     

Surface Defects on Semicoherent and Incoherent NaCl-Type Carbides Dispersed in Hot-Rolled Ferritic Steel

Metallurgical and Materials Transactions A - The interface structure of semicoherent titanium carbide (TiC) nanoparticles and incoherent micron-sized TiC precipitates in Fe–C–Ti alloy...     

Effect of anisotropic scattering in neutronics analysis of BWR assembly

The anisotropic scattering effect to keff is studied for UO₂ and MOX fueled BWR assemblies. The anisotropic scattering effect increases the assembly k_∞ by 0.44% Δk for the UO₂ assembly with 0% void fraction, and by 0.21% Δk for the MOX assembly with 0% void fraction. This is because the anisotropic scattering effect flattens the intra-assembly thermal flux, and the absorption rate in the surrounding water gap is decreased, but the absorption rates in the MOX fuel rods are increased compared to the UO₂ rods. Therefore, the total decrease in absorption rates in the UO₂ assembly is relatively large, and the k_∞ is increased in the UO₂ assembly. The dependence of the anisotropic scattering effect on the void fraction is investigated, and the significant difference of 0.62% Δk/k is found for the 0% and the 80% void fractions. The BWR assemblies with Gd rods are also considered. Furthermore, the usefulness of the transport cross section is investigated, and it is found that the transport cross section gives reasonable anisotropic scattering effect, though not satisfactory.     

Identification and C-terminal characterization of proteins from two-dimensional polyacrylamide gels by a combination of isotopic labeling and nanoelectrospray Fourier transform ion cyclotron resonance mass spectrometry

We propose a novel method for the identification and C-terminal characterization of proteins separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Proteins were digested in a gel in a buffer solution containing 50% 18O-labeled water, and mixtures of 18O/16O-labeled peptides were analyzed by nanoelectrospray Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). This method was evaluated using horse skeletal muscle myoglobin as the model protein in SDS gel. The high resolution of FT-ICR MS minimized the overlapping of peptide peaks and facilitated identification of the C-terminal peptide, which was done by observing the undisrupted isotope peak pattern. As well, with its low ppm-level high mass accuracy, it can rapidly and reliably identify the in-gel-separated protein and determine its C-terminal by peptide mass fingerprinting alone. Therefore, this method should be applicable to routine and high-throughput proteome studies. Here, the method was applied to the analysis of rat liver proteins separated by 2D-PAGE. The C-termini of eight proteins were successfully identified out of 10 randomly picked Coomassie brilliant blue-stained spots. The feasibility and limitations of this approach are reported in this paper.     

Mutation involving cytochrome P450IID6 in two Japanese patients with neuroleptic malignant syndrome

Traumatic injuries of arteries lead to acute bleeding or ischemia. In the hand, which is perfused by two arteries, this symptom could be missed. The hypothenar hammer syndrome is a traumatic occlusion of the distal arteria ulnaris. Dependent on the mechanism of the trauma the clinical symptoms may appear late. A specific angiographic or duplex sonographic diagnostic investigation is necessary to show the arterial occlusion. There is no proven therapeutic procedure. Exact diagnosis of the occlusion as an effect of the trauma is important for the patient and is the basis of any therapeutic intervention.     

A patient with acromegalic heart disease--a case report

A perioperative anesthetic management of a 69 year old woman with acromegaly whose clinical course was characterized by severe heart failure is described. The patient showed symptoms of massive cardiomegaly. Endocrine studies indicated that her pituitary tumor was active with hyperproduction of growth hormone. There was no demonstrable evidence for other known causes of heart disease. Following hormonal therapy using continuous subcutaneous infusion of somatostatin for about two months, there was improvement in daily activity and reduction in heart size. After the improvement of cardiac function, transsphenoidal hypophysectomy was performed under general anesthesia and its perioperative course was quite uneventful. We conclude that because cardiac involvement such as left ventricular dilatation in acromegaly might be reversible with proper treatment, any surgical procedure, as long as the case is elective, should be considered after hormone therapy.