Dynamic and kinetic properties of Al-Li melts

The dynamic and kinetic properties of Al-Li melts are calculated. The liquid phase of this system is shown to be characterized by three states with different ion distributions and different degrees of electron localization.     

Pneumonitis secondary to the inhalation of isocyanates. An analysis of 2 cases

We present two patients with diffuse interstitial lung disease attributed to two different forms of presentation of pneumonitis due to inhalation of isocyanates. The first case was acute and accidental and the second was due to longer workplace exposure. In both cases, clinical, radiological and lung function findings as well as results of bronchoalveolar lavage were similar to those of hypersensitivity pneumonitis triggered by organic agents.     

Dynamic recrystallization kinetic of fine grained Mg-Zn-Y-Zr alloy solidified under high pressure

Fine grained Mg_(96.17)Zn_(3.15)Y_(0.79)Zr_(0.18) alloy with an average grain size of 20 μm was prepared by high pressure solidification. The dynamic recrystallization(DRX) behavior of the fine grained Mg alloy solidified under the pressure of 4 GPa was studied via isothermal compression experiments. The tests were performed under the strain rate of 0.001–1.0 s~(–1) and at a deformation temperature of 523–623 K on a Gleeble-3500 D thermal-mechanical simulation machine. The DRX kinetic of the fine grained Mg alloy solidified under high pressure was established, and the microstructures of the alloy under different hot compression conditions were analyzed by electron back-scattering diffraction(EBSD). According to the experimental results, the DRX kinetic model of the fine grain Mg alloy solidified under high pressure was X_(DRX)=1-exp[-0.75445((ε-ε_c)/ε~*)~(1.066208).The Avrami exponents of n and k were 1.066208 and 0.75445 respectively, higher than those in the conventional casting alloy. The DRX volume fraction of the fine grain Mg alloy solidified under the pressure had a tendency to increase obviously with the strain rate decreasing and the deformation temperature increasing, which is different from the one in the conventional casting alloy. When compressed at 523 K, the DRX volume fraction of the fine grained Mg alloy solidified under high pressure was 85% under the strain rate of 1.0 s~(–1) and could be up to 95% under the strain rate of 0.001 s~(–1). The DRX volume fraction of the conventional casting alloy was only 67% although under the condition of 623–0.001 s~(–1). It was shown that the fine grained Mg alloy solidified under high pressure had a strong DRX capacity.     

Specific IgE to isocyanates: a useful diagnostic role in occupational asthma

BACKGROUND: Isocyanates are the most frequent cause of occupational asthma in industrialized countries. OBJECTIVE: We sought to investigate the utility of specific IgE measurement in the diagnosis of isocyanate-induced asthma. METHODS: Fifty-eight of 101 patients referred for investigation were diagnosed as having isocyanate-induced occupational asthma by means of history, serial peak flow records, and bronchial provocation tests. Specific IgE antibodies to toluene diisocyanate:human serum albumin (HSA), diphenylmethane diisocyanate:HSA, and hexamethylene diisocyanate: HSA were measured in all patients by Phadebas RAST. RESULTS: Twenty patients had a RAST ratio of 2 or greater to at least one isocyanate. Thirteen (28%) of the 46 patients with a positive provocation test response had a RAST ratio of 2 or greater, and nine (20%) had a RAST ratio of 3 or greater. Raising the RAST cut-off from 2 or greater to 3 or greater reduced its sensitivity but increased the specificity of the test to 100%. RAST measurement was most likely to be positive within 30 days of exposure. Serial measurements suggested that the half-life of the IgE antibodies was approximately 6 months. Evidence of cross-reactivity between isocyanate RAST responses was found in eight subjects. CONCLUSION: Specific IgE to isocyanates is a more specific than sensitive index of occupational asthma. With a RAST score of 3 or greater, it is wholly specific and therefore diagnostic of isocyanate-induced asthma. The sensitivity of specific IgE measurement is highest when blood is taken less than 30 days from last exposure, which is consistent with the observed half-life.     

Application of asymmetric TPX membranes to transdermal delivery of nitroglycerin

In this study, asymmetric poly(4-methyl-1-pentene) (TPX) membranes, fabricated by the dry/wet inversion method, were applied to transdermal delivery of nitroglycerin (NTG), a drug for treating angina pectoris. The flux of NTG through the TPX membrane was measured in vitro by a Franz cell. The results indicate that the NTG flux through asymmetric TPX membranes is strongly dependent on the membrane structure, which can be varied by adding nonsolvents in the casting solution. By adding different kinds of nonsolvents and adjusting the added amounts, membranes with different NTG release rates can be fabricated. It was also found that, with suitable drug formula, the NTG dissolution rate of a prototype TPX patch is comparable to that of a commercial patch, Transderm-Nitro. In addition, the data of NTG flux through a composite of TPX membrane and pig skin are also presented.     

Using asymmetric jaws to junction with previously treated areas

This study was conducted to determine and compare the activities of glutathione-S-transferase (GST) in red blood cells of cattle, horses, pigs, goats, dogs, rabbits, rats and mice. The highest GST activity was found in mouse red blood cells followed by that of rats, dogs, cattle, pigs, goats and horses with the lowest activity in rabbits. There were significant differences between the GST activities from these various species. The species differences in GST activities correlate with the reported variable responses of the different species to different toxicants since erythrocyte GST plays a significant role in the detoxification of circulating xenobiotics.     

Exposure to isocyanates and organic solvents, and pulmonary-function changes in workers in a polyurethane molding process

The extent of adverse health effects of isocyanates when combined with other chemicals is not well documented. This study was conducted as a 2.5-year follow-up as well as to determine daily and weekly effects of exposure to isocyanates and organic solvents on pulmonary function. The concentrations of chemicals sampled were below the recommended exposure criteria. No daily or weekly reduction in the subjects' pulmonary function was observed. The isocyanate/solvent-exposed subjects showed significant long-term reduction in their forced vital capacity (P < 0.05) and expiratory volume in 1 second (P < 0.001). No such changes were observed in non-exposed subjects or in those exposed only to organic solvents. The proportion of subjects who developed respiratory symptoms in the isocyanate-exposed group was not significantly greater than that of the non-exposed group. The results of this study indicate that long-term exposure to isocyanates, even in very low concentrations, may contribute to impaired pulmonary function.     

How to study the kinetic depth effect experimentally.

G. Sperling et al (see record 1990-06589-001) proposed an objective 3D shape identification task with 2D artifactual cues removed and with full feedback (FB) to the subjects to measure kinetic depth effect (KDE) and to circumvent algorithmically equivalent KDE-alternative computations and artifactual non-KDE processing. (1) The 2D velocity flow-field was necessary and sufficient for true KDE. (2) Only the first-order (Fourier-based) perceptual motion system could solve our task because the second-order (rectifying) system could not simultaneously process more than two locations. (3) To ensure first-order motion processing, KDE tasks must require simultaneous processing at more than two locations. (4) Practice with FB is essential to measure ultimate capacity (aptitude) and, thereby, to enable comparisons with ideal observers. Experiments without FB measure ecological achievement—the ability of subjects to extrapolate their past experience to the current stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ratcheting behavior of notched stainless steel samples subjected to asymmetric loading cycles

The ratcheting response of 316 stainless steel samples at the vicinity of notch roots under single- and multi-step load-ing conditions is evaluated. Multi-step ...     

Studies of asymmetric membrane assembly

The major capsid protein of M13 bacteriophage is incorporated at each stage of infection into the host plasma membrane with its amino terminus exposed on the outer surface. Purified M13 coat protein is incorporated with the same asymmetry into synthetic phosphatidylcholine vesicles formed near the Tm of the lipid by a cholate dilution technique. We now report that the lipid in the pre-dilution mixture exists as mixed micelles of uniform size. Prior to dilution, the coat protein is present in at least two states of aggregation, both of which behave similarly in the model membrane assembly reaction. No detectable lipid-protein interaction occurs prior to dilution. Upon dilution there is rapid production of small closed vesicles and coat protein is converted to a chymotrypsin-resistant form, presumably reflecting its incorporation into these vesicle bilayers. Formation of large (greater than 6000 A diameter) vesicles occurs slowly with preservation of coat protein asymmetry and internal volume. A model for this assembly reaction is proposed.     

Chemical and kinetic factors related to hydrogen removal from aluminum

The available data on hydrogen solubility in aluminum are reviewed. Then a mathematical analysis of the kinetics of hydrogen removal is presented. A rather complicated general equation for the hydrogen removal in batch reactors is shown to reduce to more simple expressions for certain values of anew dimensionless group, Ψ/[pct H]. This “dimensionless hydrogen concentration” can be understood to represent the ratio of the ability of hydrogen to diffuse to bubbles during their ascent divided by the capacity of the purge gas to remove hydrogen. When ψ/[pct H] ≼ 0.1, diffusion of hydrogen in the metal is rate controlling. When ψ/Ipct H] 3> 1.0, the purge gas concentration is essentially at equilibrium with the melt, and thermodynamic limitations apply. The mathematical analysis has been used, together with available data on the diffusion coefficient of hydrogen and on mass transfer coefficients, to describe the operation of industrial processes. Then a theoretical analysis of vacuum treatment is presented. The vacuum is seen to remove partially equilibrium limitations found at atmospheric pressure. G. K. SIGWORTH, formerly Visiting Scientist at The Norwegian Institute of Technology.