The anodic behavior of amorphous Ni-19P alloys in different amorphous states

An amorphous Ni-19P alloy prepared by rapid quenching of white heat melt showed a higher anodic dissolution current density in 1 N HCl in comparison with the same amorphous alloy prepared by rapid quenching of red heat melt. After structural relaxation these two specimens showed the same anodic polarization curve which is located between the polarization curves of as-quenched two specimens. The thermograms of these two as-quenched specimens were different from each other, showing that the difference in the amorphous states is due to the difference in structural relaxation during preparation. The difference in anodic behavior between these two as-quenched specimens seems due to the difference in the amounts of quenched-in defects. The higher current density of the relaxed specimen in comparison with the as-quenched specimen prepared by rapid quenching of the red heat melt has been interpreted in terms of introduction of chemical heterogeneity as a result of rearrangement and regroupings of atoms in the alloy during structural relaxation. The steady state current density was fairly low in the low potential region without showing a difference between two as-quenched specimens and then increased with increasing polarization potential. The difference in the quality of as-quenched alloy specimens seemed to be masked by the formation of phosphorus-covered alloy surfaces during anodic polarization at potentials lower than about 200 mV(SCE), because of a negligibly small dissolution rate constant of phosphorus in comparison with that of nickel.     

The extraction of iron(III) from aqueous acid solutions by di(2-ethylhexyl)phosphoric acid

The extraction of iron(III) from aqueous solutions containing sulphuric, hydrochloric and nitric acids by di(2-ethylhexyl)phosphoric acid (DEHPA) in kerosene has been investigated under different conditions. As a result, it is found that although extraction is dominated by an ion-exchange reaction, the rate of iron(III) extraction from sulphuric acid solutions to reach equilibrium is relatively slow in comparison with that from hydrochloric or nitric acid solutions. In the extraction from aqueous solutions containing hydrochloric or nitric acid, however, the DEHPA combines with iron(III) according to the solvating reaction at higher aqueous acidity. From studies on the rate of the extraction from sulphuric acid solutions, examined under non-equilibrium, it is confirmed that dependencies of extraction rate on hydrogen ion and DEHPA concentrations are in the first and inverse first orders, respectively. The hydrolyzed species is considered to interpret the extraction mechanism in this system.     

HL-004, the ACAT inhibitor, prevents the progression of atherosclerosis in cholesterol-fed rabbits

HL-004, N-(2,6-diisopropylphenyl) tetradecylthioacetamide, a novel acyl-CoA:cholesterol acyltransferase (ACAT) inhibitor, was evaluated concerning the possible prevention of hyperlipidemia and atherosclerosis in 1% cholesterol-fed rabbits. HL-004 (0.2, 5 and 25 mg/kg) was orally administered once a day for 12 weeks. HL-004 inhibited the rise of total serum cholesterol at a dose of 5 mg/kg and over. In the thoracic aorta, HL-004 at the doses of 5 mg/kg and 25 mg/kg reduced the total cholesterol content by 56.3% and 84.2% compared with control, and decreased ACAT activity, dose-dependently. HL-004 also attenuated the development of aortic lesions. The area of atherosclerotic lesions was reduced by 30.3% with 5 mg/kg of HL-004 and 100% with 25 mg/kg. In this study, we suggest that the main reason for HL-004 preventing the progression of atherosclerosis is its hypocholesterolemic effect due to the inhibition of cholesterol absorption in the intestine.     

Stability and characterization of phospholipid Langmuir-Blodgett films

The regularity of the bilayer structure was compared between dipalmitoylphosphatidic acid (DPPA) Langmuir-Blodgett (LB) films and “oriented multilayers” of DPPA, using X-ray diffraction and electron spectroscopy for chemical analysis (ESCA). The angular variation of the (001) Bragg spot due to the irregularity of the lamellar repeat was remarkable in the system of oriented multilayers. In contrast, the spot of DPPA LB films exhibited only a slight angular variation, suggesting a regular structure of this film. The take-off angle dependence of the phosphorus:carbon ratio obtained by ESCA indicates that the regular layered structure in DPPA LB film is maintained after 49 layers are deposited.     

Ranges of low energy 119Sb and 125I in metals

Mean ranges of ¹¹⁹Sb in tin and ¹²⁵I in copper have been measured for the energy region of 10 keV to 60 keV by using the samples prepared by ion-implantation of these nuclides into vacuum-evaporated layers of metals. The observed ranges are in good agreement with those predicted by the theory of Lindhard et al. for 0.1 > ? > 0.02, but they are slightly smaller for 0.02 > ? > 0.01 in terms of the dimensionless energy ?.     

Temperature dependence of tensile strength and hardness for nodular cast iron and their mutual correlation

Nodular cast iron has mechanical properties which make it superior to relatively brittle pig cast iron. As a matter of fact, by using appropriate heat treatment processes, the tensile strength of nodular cast iron can be improved to such a degree that its hardness corresponds to that of carbon steels. The main aims in this study are to find the most preferable heat treatment conditions which will yield high strength levels, and to clarify the temperature dependence of mechanical properties for nodular cast iron. The estimation of tensile strength from hardness is also discussed, since tensile tests at elevated temperatures are usually more expensive and time consuming than the hardness tests. Nodular cast irons, having four different microstructures were first prepared by performing the following heat treatments: (1) as-cast, (2) annealed, (3) normalized and (4) bainitized. Tensile property and hardness were then measured for the respective cast irons under elevated temperatures. The temperature dependence of the tensile strength as well as hardness was investigated. It was found that the dependence was well represented by an expression of =₀exp(–BT). Thus results were discussed from a view-point of the reaction rate process. The correlation between tensile strength and hardness was also examined and a significant linearity was found between them. Based on this strict correlation, an estimation procedure of the tensile strength was finally proposed.     

Preparation of high-T c superconducting film in the system of Bi-Sr-Ca-Cu-O from sol-gel process and its properties

High-T _c superconducting Bi₂Sr₂CaCu₂O_x films withT _c ^off =80 K were prepared by the dipping method of sol-gel processing using inorganic salts. The influence of the preparation conditions on the superconducting properties of the derived material is reviewed. Bi, Sr, Ca and Cu nitrates were used as raw materials. Glycerol was used as solvent. The thickness of films made by the dip method was about 0.5 m. The films were crystallized by heat-treatment at 830°C for 10 min.T _c ^off of films was 80 K andJ _c at 77 K was more than 8 kA cm^–2. Synthesis of high-T _c superconducting films was very easy and the crystallization of films was possible with a relatively low heat-treatment temperature.     

Design and Synthesis of A‐Ring Simplified Pyripyropene A Analogues as Potent and Selective Synthetic SOAT2 Inhibitors

Currently, pyripyropene A, which is isolated from the culture broth of Aspergillus fumigatus FO‐1289, is the only compound known to strongly and selectively inhibit the isozyme sterol O‐acyltransferase 2 (SOAT2). To aid in the development of new cholesterol‐lowering or anti‐atherosclerotic agents, new A‐ring simplified pyripyropene A analogues have been designed and synthesized based on total synthesis, and the results of structure–activity relationship studies of pyripyropene A. Among the analogues, two A‐ring simplified pyripyropene A analogues exhibited equally efficient SOAT2 inhibitory activity to that of natural pyripyropene A. These new analogues are the most potent and selective SOAT2 inhibitors to be used as synthetic compounds and attractive seed compounds for the development of drug for dyslipidemia, including atherosclerotic disease and steatosis.