Production technology of large-area multicrystalline silicon solar cells

In 1996 a conversion efficiency of 17.1% had been obtained on 15 cm×15 cm mc-Si solar cell. In this paper, large-scale production technology of the high-efficiency processing will be discussed. Enlarging reactive ion etching (RIE) equipment size, technology of passivation, and fine contact grid with low resistance by screenprinted metallization, which is firing through PECVD SiN, have been investigated.     

Synthesis of geranyl acetate by lipase entrap-immobilized in cellulose acetate-TiO2 gel fiber

Lipase from Candida antarctica was entrap-immobilized in cellulose acetate-TiO₂ gel fiber (fiber-immobilized lipase) by the sol-gel method. Syntheses of geranyl acetate and citronellyl acetate catalyzed by the fiber-immobilized lipase were studied in heptane solution. Conversions reached 85% for geranyl acetate after 100 h, and 75% for citronellyl acetate after 80 h, and these values were almost identical to those for syntheses catalyzed by nonimmobilized lipase, although the reaction rate was decreased by immobilization. Compared to those of the non-immobilized lipase and commercially available immobilized lipase (Novozyme 435), the activity of the fiber-immobilized lipase was not particularly affected by changes in reaction conditions, such as bulk water content or substrate concentration. The fiber-immobilized lipase retained a high level of activity after six repeated uses, and almost no enzyme leakage from fiber was observed. However, the reactivity of the fiber-immobilized lipase was depressed at higher temperature, presumably due to dehydration by thermal contraction of the gel fiber.     

To Separate a Particular Ln(III) Selectively Using Solvent Extraction

ABSTRACT

Since a particular trivalent lanthanide (Ln(III)) often plays a unique role in different industrial applications, the development of a selective separation method to get only the requisite Ln(III) would be most convenient. Synergistic extraction with β-diketone (HA) and Lewis base (B), which has been extensively used for the separation of lanthanides, relies on two processes: the extraction with HA as LnA₃ into the organic phase and the complexation of LnA₃ with B as LnA₃B in the organic phase. The variation in the pattern of the extraction constants of LnA₃ across the Ln series correlates with the number of CF₃- group in the β-diketones, and with the stability constants of LnA₃B of different Lewis bases. It is seen that the constants with bipyridyl increase with increasing atomic number, while those with POPO (methylenediphosphonate) and MePhPA (methylphenylphenanthroline carboxamide) decrease with increasing Ln atomic number. Using pivaloyltrifluoroacetone as the β-diketone and MePhPA, the best extractability appeared at Sm(III) among the series. As a conclusion, to get only a required Ln(III), the combination of β-diketone and Lewis base is very important. In addition, the separation of Lns(III) from other metals and the use of new extractants developed recently and reported in literature were referred to find out more effective extractants and selective separation methods.     

Pathophysiology of Preeclampsia: The Role of Exosomes

The pathogenesis of preeclampsia begins when a fertilized egg infiltrates the decidua, resulting in implantation failure (e.g., due to extravillous trophoblast infiltration disturbance and abnormal spiral artery remodeling). Thereafter, large amounts of serum factors (e.g., soluble fms-like tyrosine kinase 1 and soluble endoglin) are released into the blood from the hypoplastic placenta, and preeclampsia characterized by multiorgan disorder caused by vascular disorders develops. Successful implantation and placentation require immune tolerance to the fertilized egg as a semi-allograft and the stimulation of extravillous trophoblast infiltration. Recently, exosomes with diameters of 50–100 nm have been recognized to be involved in cell–cell communication. Exosomes affect cell functions in autocrine and paracrine manners via their encapsulating microRNA/DNA and membrane-bound proteins. The microRNA profiles of blood exosomes have been demonstrated to be useful for the evaluation of preeclampsia pathophysiology and prediction of the disease. In addition, exosomes derived from mesenchymal stem cells have been found to have cancer-suppressing effects. These exosomes may repair the pathophysiology of preeclampsia through the suppression of extravillous trophoblast apoptosis and promotion of these cells’ invasive ability. Exosomes secreted by various cells have received much recent attention and may be involved in the maintenance of pregnancy and pathogenesis of preeclampsia.     

Identification of a novel MHC class I gene, Mamu-AG, expressed in the placenta of a primate with an inactivated G locus

Maternal tolerance of the fetal allograft remains poorly understood. In humans, expression of the highly polymorphic classical HLA-A and HLA-B loci is suppressed, while expression of the nonclassical HLA-G locus is up-regulated at the maternal-fetal interface. Like other nonclassical MHC class I molecules, HLA-G exhibits limited diversity, but certain characteristics of HLA-G distinguish it from other nonclassical MHC class I molecules: it has a truncated cytoplasmic domain, it is the product of alternatively spliced mRNAs, and it is expressed primarily in the placenta. We have examined MHC class I expression in the placenta of the rhesus monkey to determine whether this animal is a suitable model in which to study the function of HLA-G. Although the rhesus monkey possesses orthologs of many MHC class I and II loci found in humans, the HLA-G ortholog is a pseudogene in this nonhuman primate species. In this study, we report the identification of a novel nonclassical MHC class I locus expressed in the placenta of the rhesus monkey, Mamu-AG (Macaca mulatta-AG). Although unrelated to HLA-G, Mamu-AG encodes glycoproteins with all of the characteristics of HLA-G. These Mamu-AG glycoproteins are limited in their diversity, possess truncated cytoplasmic domains, are the products of alternatively spliced mRNAs, and their expression is restricted to the placenta. Taken together, these data suggest that convergent evolution may have resulted in the expression of a unique nonclassical MHC class I molecule in the rhesus monkey placenta, and that the common structural features of Mamu-AG and HLA-G may be functionally significant.     

Reversed passive latex agglutination assay for detection of toxigenic Corynebacterium diphtheriae

A reversed passive latex agglutination (RPLA) assay for determining the toxigenicity of Corynebacterium diphtheriae is presented. Rabbit antitoxin antiserum was raised by using commercially available diphtheria toxoid. This antiserum reacted with the diphtheria toxin when the culture supernatant was assayed by Western blotting, and it did not cross-react with other extracellular antigens. Affinity-purified antibodies for latex sensitization were obtained by using a Hi Trap N-hydroxysuccinimide-activated column. Demonstration of toxin in five of seven clinical isolates was in accordance with the PCR assay and the Vero cell cytotoxicity test. Culture of the bacteria for 6 h was sufficient for toxin production, and an additional 6 h was needed to observe latex agglutination. Therefore, diphtheria toxin can be detected in 12 h by this method. The lowest concentration of diphtheria toxin detectable by the RPLA assay was about 5 ng/ml. The RPLA assay can provide a convenient and reliable method for laboratories involved in the identification of toxinogenic corynebacteria.     

Morphology and rotation twin in ZnSe on GaAs (111)

ZnSe crystals were grown by a vapour transport method on a GaAs substrate with a (111) A or (¯1¯1¯1) B surface. Crystals obtained on the (111) A surface of the substrate were fine crystals and hexagonal plates. Whereas crystals grown on the (¯1¯1¯1) B were uniform thin films on which trigonal hills and trigonal pyramids developed. These crystallites had a complicated morphology. In addition, the hill and pyramid grown on the (¯1¯1¯1) B surface contained rotation twins around a polar axis parallel to the growth direction or around the other polar axes.     

Use of plastic bar molded casting in the modification of variably expanding investment to compensate for casting shrinkage of nickel-chromium alloy

Trial plastic bar molded castings were compared for accuracy with cast crowns by means of a nickel-chromium alloy, which was used to establish the liquid density of variably expanding investments. The plastic bars were invested to evaluate the change of expansion rate in a wide range of six liquid densities from 0% to 100%, and the distances between the sections were measured before and after casting. Wax crowns were cast to obtain a more detailed relation around 0% expansion at seven liquid densities, and the gaps between the base of the die and the margin of the crown were measured before and after casting. The expansion rates of both castings were calculated and thus were proportional to the liquid density; both regression curves indicated high correlation coefficients. As a result of the statistics of the Student's t-test, the difference between the two methods was not significant. The trial plastic bar was useful in establishing the variably expanding investment for precise casting of artificial crowns.