Biodiesel fuel production from plant oil catalyzed by Rhizopus oryzae lipase in a water-containing system without an organic solvent

A new enzymatic method of synthesizing methyl esters from plant oil and methanol in a solvent-free reaction system was developed. It is anticipated that such plant oil methyl esters can be used as a biodiesel fuel in the future. Lipase from Rhizopus oryzae efficiently catalyzed the methanolysis of soybean oil in the presence of 4–30 wt% water in the starting materials; however the lipase was nearly inactive in the absence of water. The methyl ester (ME) content in the reaction mixture reached 80–90 wt% by stepwise additions of methanol to the reaction mixture. The kinetics of the reaction appears to be in accordance with the successive reaction mechanism. That is, the oil is first hydrolyzed to free fatty acids and partial glycerides, and the fatty acids produced are then esterified with methanol. Although R. oryzae lipase is considered to exhibit 1(3)-regiospecificity, a certain amount of 1,3-diglyceride was obtained during the methanolysis and hydrolysis of soybean oil by R. oryzae lipase solution. Therefore, the high ME content in the reaction mixture is probably attributable to the acyl migration from the sn-2 position to the sn-1 or sn-3 position in partial glycerides.     

Texture and electromigration lifetime improvements in layered Al-alloy metallization with underlying Ti by controlling water adsorption on SiO2 substrates

The effect of residual gas constituents and substrate temperature during Ti sputtering on the texture of TiN/Ti films deposited on SiO₂/Si substrates has been investigated. The Ti(002) and TiN(111) preferred texture of the films deposited at 350°C was found to be improved drastically by increasing the H₂O partial pressure from 1×10⁻⁹ to 3×10⁻⁸ Torr. Both of the Ti(002) and TiN(111) textures showed a similar H₂O partial pressure and substrate temperature dependence because of the epitaxial transfer between these planes. The improved Ti(002) texture was attributed to the self-assembly of Ti atoms on the SiO₂ surface, which had a low surface free energy due to the formation of surface OH groups. Two kinds of layered Al-alloy interconnects, AlSiCu/Ti/TiN/Ti and AlCu/TiN/Ti, were fabricated with the highly textured TiN/Ti film, and their Al(111) texture and electromigration lifetime were then evaluated. It was confirmed that both of the interconnects have strong Al(111) texture and longer EM lifetimes.     

Carbon film from polyphenylene prepared by electrochemical polymerization

A carbon film was produced from polyphenylene (PP) film prepared by electrochemical polymerization of benzene to obtain a uniform and thin film. The PP film (～10μm thick) was transformed into the carbon or graphite film without drastic changes of shape or size. The electrical conductivity of the film was remarkably enhanced by heat-treatment between 600 and 800° C, but further increase in the conductivity was not observed by treating at higher temperatures. This behaviour is considered to correlate with a poor degree of graphitization of the PP film. The carbonization and graphitization mechanisms of the film are discussed in connection with the structure of polyphenylene in the film.     

Measurement and evaluation of the thermal diffusivity of two-layered materials

Transient methods, such as those with pulse- or step-wise heating, have often been used to measure thermal diffusivity of various materials including layered composite materials. The aim of the present study is to investigate effects of various parameters on the measurement of thermal diffusivity when the transient methods are applied. Mainly a two-layered material in the pulsewise heating method is considered because of its simplicity and usefulness in identifying and determining the effects of the parameters. First, it has been shown that there exists a special condition for determining the thermal diffusivity of a component in the two-layered material whose other relevant thermophysical properties are known. Second, it has been shown that the thickness of the laserbeam absorption layer, which inevitably makes sample material into the twolayered material, may cause a relatively large error when the thermal diffusivity of the base material is high. Finally, it has been derived a definite relation between the apparent thermal diffusivity obtained from the temperature response and the mean thermal diffusivity, which has a physical meaning related to the thermal resistance.     

ESCA study on the destruction mechanism of metal-resin adhesion due to water penetrating through the resin

The mechanism destroying the adhesion between PMMA and mild steel, and the action of water molecules reaching the adhesion interface was investigated. Mild steel and a thin PMMA film were bonded with dental adhesive (4-META resin). After immersion in water, the adhesive layer was peeled from the metal surface. The surface was analysed by ESCA, reflection electron diffraction, and X-ray diffraction to elucidate changes in surface structure. After 2 weeks immersion, there was a very thin brown product and after 2 months a thick black corrosion product composed of Fe₃O₄ formed at the adhesion interface. The thin brown layer showed no X-ray diffraction pattern but reflection electron diffraction showed it to be FeO(OH). After 3 days immersion, the mild steel surface appeared unchanged through the clear resin layer, and ESCA analysis showed the same chemical state as the surface of the specimen immersed for 2 weeks. Destruction of adhesion between metal and adhesive is caused by destruction of the chemical bond by the water molecules permeating through the resin layer. It is followed by corrosion of mild steel which produced iron oxide hydrate.     

Relation of serum total cholesterol, serum triglycerides and fasting plasma glucose to colorectal carcinoma in situ

BACKGROUND: No one has previously examined the relation of serum total cholesterol, serum triglycerides and fasting plasma glucose to colorectal carcinoma in situ. METHODS: A case-control study was performed with 129 cases of colorectal carcinoma in situ and 258 matched controls among examinees undergoing a health check-up in Tokyo from January 1991 to March 1993. RESULTS: There was a significant, positive association between serum total cholesterol levels and the risk of colorectal carcinoma in situ after adjustment for age, sex, body mass index, smoking status and alcohol consumption. Serum triglyceride levels were significantly and positively associated with colorectal carcinoma in situ risk regardless of adjustment for the above covariates. Although there was no clear relation between colorectal carcinoma in situ and fasting plasma glucose levels, a modest increase of colorectal carcinoma in situ risk was observed in the highest category (> or =116 mg/dl) of fasting plasma glucose levels. CONCLUSIONS: The findings suggest a positive association between serum total cholesterol levels and the risk of colorectal cancer, rather than an inverse relation. The strong association with serum triglyceride levels and the weak association with fasting plasma glucose levels support the hypothesis that hyperinsulinaemia may play an important role in colorectal carcinogenesis.     

Radiotherapy for carcinoma of the buccal mucosa: analysis of prognostic factors]

The radiotherapeutic results of 55 patients with carcinoma of the buccal mucosa were analyzed to determine the prognostic factors and appropriate treatment modality. They were classified into 5 groups according to treatment modality: group A (preoperative radiotherapy followed by surgery), group B (interstitial implant), group C (electron therapy), group D (mainly external radiotherapy) and group E (external radiotherapy followed by mold therapy with remote afterloading system). The overall 5-year survival rates for groups A, B, C, D, E and the entire group were 50%, 61%, 67%, 29%, 25% and 48%, respectively. The cumulative 5-year local control rates for groups A through E were 81%, 94%, 75%, 33% and 25%, respectively. In univariate analysis, T stage (T1-2 vs. T3-4), N stage (N0 vs. N1-3), clinical stage (II vs. III-IV), histologic grade (well differentiated vs. moderately and poorly differentiated) and treatment modality (A-C vs. D-E) were significantly related to overall survival (p < 0.05). Multivariate analysis revealed that treatment modality (groups A-C) and N0 stage were significantly associated with favorable prognosis (p < 0.05). These results suggest that interstitial implants are comparable with surgery for T1 to early T3 lesions, with or without slight invasion to the bucco-alveolar sulci or retromolar areas, that can be treated with a single-plane implant.     

Evaluation of orthodontic results with fuzzy inference

Evaluation of the results of orthodontic treatment is crucial for the improvement of the practitioner's therapeutic skills. Conventional methods of appraisal are based on ill-defined subjective criteria, however, or fail to make their criteria explicit. In order to provide a more objective appraisal, we surveyed 10 experienced practitioners regarding their criteria for evaluating 12 items such as the overjet, or the amount of horizontal projection of the upper front teeth beyond the lower ones. For each item, their opinions were averaged as the definition of membership in the category of “completely favorable.” Algorithms were devised for comparing the posttreatment results with the pre-treatment condition of need, in order to evaluate the degree of therapeutic success. the average of all 12 evaluations is taken as the appraisal of treatment. A hardware system incorporating these algorithms has been developed. This system, representing the first successful application of fuzzy inference to the evaluation of orthodontic treatment, is expected to provide orthodontists with an accurate and objective means of making such an appraisal and thereby help improve their therapeutic skills. © 1994 John Wiley & Sons, Inc.