Structural Relaxation Behaviors of Three Different Asphaltenes Using MD Calculations

For asphaltene obtained from vacuum residues of three different kinds of crude oils (Khafji, Maya, and Iranian-Light), the energy-minimum conformation calculated by molecular mechanics-dynamics simulations showed that aggregated structures of asphaltene molecules through noncovalent interactions are the most stable conformation. Changes of aggregated structures by heating or solvent treatment were investigated by using the molecular dynamics calculation. For Khafji and Iranian-Light asphaltenes, the simulation showed that the aggregated structure was dissociated at 673K, while for Maya asphaltene the dissociation behavior was not observed, showing that Maya asphaltene seems difficult to be dissociated by heating, compared to other asphaltenes. In contrast, the simulation of relaxation of the Maya aggregates in quinoline showed that at 573K a part of aggregates was dissociated more easily than Khafji and Iranian-Light asphaltenes. These results above suggest that the effects of heating and solvent treatment on the structural relaxation of asphaltene aggregates can be different.     

Dynamic behavior of an all-optical inverter using transverse-mode switching in 1.55-/spl mu/m vertical-cavity surface-emitting lasers

An all-optical inverter using transverse-mode switching of a 1.55-/spl mu/m vertical-cavity surface-emitting laser is demonstrated. When an external light is injected to a first high-order mode, the output power of the fundamental mode is strongly suppressed due to injection locking resulting in a large extinction ratio of over 20 dB. Waveform inversion is demonstrated for the input signal of a 5-GHz sinusoidal wave.     

Energy analysis of a Kori-tofu plant

Consumption of energy was analysed on a Kori-tofu plant which processed 6 tons of soybeans per day, involving 13 operations such as wetmilling, extraction-denaturation of soy protein, coagulation, compression, freezing, thawing, drying and waste-water treatment. Total energy consumption per 1 kg of the dry Kori-tofu was 27·1 MJ of fuel energy (27·9 MJ of exergy) plus 8·3 MJ of electrical energy. Energy-intensive operations were the extraction-denaturation of soy protein and the drying for thermal energy, and the refrigeration and the waste-water treatment for electrical energy. The extraction-denaturation of soy protein consumed twice as much thermal energy as the drying. The waste-water treatment consumed more electrical energy than the whole manufacturing process. Points for energy conservation are discussed.     

Prevention of restenosis by bezafibrate after successful coronary angioplasty

BACKGROUND: To study the role of bezafibrate in prevention of restenosis after successful percutaneous transluminal coronary angioplasty (PTCA), we evaluated the incidence of restenosis and its correlation with serum lipid levels and effects on the coagulation-fibrinolytic system. METHODS: Subjects who had undergone successful elective PTCA were classified into three groups based on their triglyceride level and whether or not bezafibrate was administered. Fifty-two patients who had a triglyceride level < 150 mg/dl were classified as group A. Those with a triglyceride level +/- 150 mg/dl were randomly and prospectively allocated to receive either bezafibrate (group B, n = 21), or no lipid-lowering treatment (group C, n = 22). The restenosis rates in all three groups were subsequently monitored and correlated with serum levels of lipids and coagulation-fibrinolytic system markers. RESULTS: In the bezafibrate group, three of 21 patients (14%) had restenosis compared with 12 of 22 (55%) in group C and 18 of 52 (35%) in group A. In groups A and C, fibrinogen and triglyceride levels were significantly higher in the patients with restenosis. At the time of re-evaluation, serum triglyceride, fibrinogen, and plasminogen activator inhibitor type 1 (PAI-1) levels were lower and high-density lipoprotein (HDL) cholesterol levels were higher in the bezafibrate group than in group C. By logistic regression analysis, triglyceride and PAI-1 were found to be significant risk factors for postangioplasty restenosis. CONCLUSIONS: Triglyceride is a risk factor for post-PTCA restenosis, and bezafibrate reduces the post-PTCA restenosis rate in patients with a high triglyceride level. In the bezafibrate group, a significant decrease in PAI-1 was observed in association with a decrease in triglyceride level and an elevation of HDL cholesterol level. This suggests that improvement in fibrinolytic capacity is involved in the mechanism of decrease in the rate of restenosis.     

Iodine induced thyroid disease

Although iodine prevents goiter, enlarged thyroid glands continue to be detected in subjects, especially children, in spite of adequate iodine ingestion. Iodine may cause goiter in susceptible individuals by inhibiting the organic binding of iodine as is seen in adult asthmatics, neonates born of iodine ingesting mothers and in subjects residing along the littoral of Japan. Myxedema, especially in treated Graves' disease and Hashimoto's disease, may also be precipitated by iodine. On the other hand, iodine given to euthyroid subjects in areas of endemic goiter and to subjects with nontoxic nodular goiter may induce thyrotoxicosis by disclosing diffuse autonomously functioning thyroid tissue. An indirect adverse effect of iodine upon the thyroid gland may be manifested by lymphocyte glandular infiltrates and chronic thyroiditis which were sparse or absent in thyroid glands removed from subjects living in iodine deficient areas before iodine prophylaxis and therapy. Not only has the incidence of thyroiditis increased, but the histologic and clinical distinctions between treated Graves' disease and chronic thyroiditis have become indistinct. Experimentally, chronic thyroiditis has been produced in animals following large doses of iodine. Accumulated evidence supports the concept that iodine contributes to the genesis of chronic thyroiditis.