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131.
Teresa Ros-Dosdá Irina Celades Eliseo Monfort Pere Fullana-i-Palmer 《The International Journal of Life Cycle Assessment》2018,23(8):1562-1580
Purpose
Porcelain stoneware tile (PST) is currently the ceramic tile of greatest commercial and innovation interest. An environmental life cycle assessment of different varieties of PST was undertaken to enable hotspots to be identified, strategies to be defined, differences between PST varieties to be evaluated and guidance for PST manufacturers to be provided in choosing the Environmental Product Declaration (EPD) programme that best suited their needs according to grouping criteria.Methods
Analysis of previous information allowed three main parameters (thickness, glaze content and mechanical treatment) to be identified in order to encompass all PST variations. Fifteen varieties of PST were thus studied. The coverage of 1 m2 of household floor surface with the different PST varieties for 50 years was defined as functional unit. The study sets out environmental data whose traceability was verified by independent third parties for obtaining 14 EPDs of PST under Spanish EPD programmes.Results and discussion
The study presents PST inventory analysis and environmental impact over the entire life cycle of the studied PST varieties. The natural gas consumed in the manufacturing stage accounted for more than 70% abiotic depletion–fossil fuels and global warming; electricity consumption accounted for more than 60% ozone layer depletion, while the electricity generated by the cogeneration systems avoided significant environmental impacts in the Spanish power grid mix. The variations in PST thickness, amount of glaze and mechanical treatments were evaluated. The PST variety with the lowest environmental impact was the one with the lowest thickness, was unglazed and had no mechanical treatments. Similarly, the PST variety with the highest environmental impact was the one with the greatest thickness, was glazed and had been mechanically treated.Conclusions
The PST life cycle stage with the highest environmental impact was the manufacturing stage. The main hotspots found were production and consumption of energy and raw materials extraction. Variation in thickness was a key factor that proportionally influenced almost all studied impact categories; the quantity of glaze strongly modified abiotic depletion–elements and eutrophication, while the mechanical treatments contributed mainly to ozone depletion. The study of all PST varieties led to the important conclusion, against the current trend, that differences among them were found to be so significant that declaring a number of PSTs within the same EPD is not directly possible, and it needs preliminary verification to ensure compliance with the product category rule.132.
Violeta Datcheva Aleksei Kamernitskii Radoslav Vlahov Natalia Voishvillo Vera Levi Irina Reshetova Elena Chernoburova 《Applied microbiology and biotechnology》1986,25(1):14-17
Summary A high-yield microbiological transformation of polyfunctional 5-3-acetoxy steroids, containing an additional ring E, by Corynebacterium mediolanum strain B-964 was carried out, resulting in the corresponding 4-3-ketones. It was shown that the type of transformation and the yield of the reaction depend on the degree of saturation of the ring E and on the position of the oxygen-containing substituents in it. 相似文献
133.
George Calin Guglielmina N Ranzani Dino Amadori Vlad Herlea Irina Matei Giuseppe Barbanti-Brodano Massimo Negrini 《BMC genetics》2001,2(1):14-7
Background
Genomic instability has been reported at microsatellite tracts in few coding sequences. We have shown that the Bloom syndrome BLM gene may be a target of microsatelliteinstability (MSI) in a short poly-adenine repeat located in its coding region. To further characterize the involvement of BLM in tumorigenesis, we have investigated mutations in nine genes containing coding microsatellites in microsatellite mutator phenotype (MMP) positive and negative gastric carcinomas (GCs). 相似文献134.
Prions are self-propagating conformations of proteins that can cause heritable phenotypic traits. Most yeast prions contain glutamine (Q)/asparagine (N)-rich domains that facilitate the accumulation of the protein into amyloid-like aggregates. Efficient transmission of these infectious aggregates to daughter cells requires that chaperones, including Hsp104 and Sis1, continually sever the aggregates into smaller “seeds.” We previously identified 11 proteins with Q/N-rich domains that, when overproduced, facilitate the de novo aggregation of the Sup35 protein into the [PSI
+] prion state. Here, we show that overexpression of many of the same 11 Q/N-rich proteins can also destabilize pre-existing [PSI
+] or [URE3] prions. We explore in detail the events leading to the loss (curing) of [PSI+] by the overexpression of one of these proteins, the Q/N-rich domain of Pin4, which causes Sup35 aggregates to increase in size and decrease in transmissibility to daughter cells. We show that the Pin4 Q/N-rich domain sequesters Hsp104 and Sis1 chaperones away from the diffuse cytoplasmic pool. Thus, a mechanism by which heterologous Q/N-rich proteins impair prion propagation appears to be the loss of cytoplasmic Hsp104 and Sis1 available to sever [PSI
+]. 相似文献
135.
Yan Zhang Orgil Elbegdorj Yunyun Yuan Irina O. Beletskaya Dana E. Selley 《Bioorganic & medicinal chemistry letters》2013,23(13):3719-3722
Isosterism is commonly used in drug discovery and development to address stability, selectivity, toxicity, pharmacokinetics, and efficacy issues. A series of 14-O-substituted naltrexone derivatives were identified as potent mu opioid receptor (MOR) antagonists with improved selectivity over the kappa opioid receptor (KOR) and the delta opioid receptor (DOR), compared to naltrexone. Since esters are not metabolically very stable under typical physiological conditions, their corresponding amide analogs were thus synthesized and biologically evaluated. Unlike their isosteres, most of these novel ligands seem to be dually selective for the MOR and the KOR over the DOR. The restricted flexibility of the amide bond linkage might be responsible for their altered selectivity profile. However, the majority of the 14-N-substituted naltrexone derivatives produced marginal or no MOR stimulation in the 35S-GTP[γS] assay, which resembled their ester analogs. The current study thus indicated that the 14-substituted naltrexone isosteres are not bioisosteres since they have distinctive pharmacological profile with the regard to their opioid receptor binding affinity and selectivity. 相似文献
136.
137.
Marjan Shafaati Natalia Mast Olof Beck Rima Nayef Gun Young Heo Linda Bj?rkhem-Bergman Dieter Lütjohann Ingemar Bj?rkhem Irina A. Pikuleva 《Journal of lipid research》2010,51(2):318-323
Cholesterol 24S-hydroxylase (CYP46A1) is of key importance for cholesterol homeostasis in the brain. This enzyme seems to be resistant toward most regulatory factors and at present no drug effects on its activity have been described. The crystal structures of the substrate-free and substrate-bound CYP46A1 were recently determined (Mast et al., Crystal structures of substrate-bound and substrate-free cytochrome P450 46A1, the principal cholesterol hydroxylase in the brain. Proc. Natl. Acad. Sci. USA. 2008. 105: 9546–9551). These structural studies suggested that ligands other than sterols can bind to CYP46A1. We show here that the antifungal drug voriconazole binds to the enzyme in vitro and inhibits CYP46A1-mediated cholesterol 24-hydroxylation with a Ki of 11 nM. Mice treated with daily intraperitoneal injections of voriconazole for 5 days had high levels of voriconazole in the brain and significantly reduced brain levels of 24S-hydroxycholesterol. The levels of squalene, lathosterol, and HMG-CoA reductase mRNA were reduced in the brain of the voriconazole-treated animals as well, indicating a reduced cholesterol synthesis. Most of this effect may be due to a reduced utilization of cholesterol by CYP46A1. One of the side-effects of voriconazole is visual disturbances. Because CYP46A1 is also expressed in the neural retina, we discuss the possibility that the inhibition of CYP46A1 by voriconazole contributes to these visual disturbances. 相似文献
138.
Irina V. Tereshchenko Yanping Chen Lisa D. McDaniel Roger A. Schultz Jay A. Tischfield Changshun Shao 《DNA Repair》2010,9(5):551-557
BLM, the gene mutated in Bloom syndrome (BS), encodes an ATP-dependent RecQ DNA helicase that is involved in the resolution of Holliday junctions, in the suppression of crossovers and in the management of damaged replication forks. Cells from BS patients have a characteristically high level of sister chromatid exchanges (SCEs), and increased chromosomal aberrations. Fibroblasts and lymphocytes of BS patients also exhibit increased mutation frequency at the X-linked reporter gene HPRT, suggesting that BLM also plays a role in preventing small scale genomic rearrangements. However, the nature of such small scale alterations has not been well characterized. Here we report the characterization of Hprt mutations in vivo in Blm hypomorphic mice, Blmtm1Ches/Blmtm3Brd. We found that the frequency of Hprt mutants was increased about 6-fold in the Blmtm1Ches/Blmtm3Brd mice when compared to Blmtm3Brd heterozygous mice or wildtype mice. Molecular characterization of Hprt gene in the mutant clones indicates that many of the mutations were caused by deletions that range from several base pairs to several thousand base pairs. While deletions in BLM-proficient somatic cells are often shown to be mediated by direct repeats, all three deletion junctions in Hprt of Blmtm1Ches/Blmtm3Brd mice were flanked by inverted repeats, suggesting that secondary structures formed during DNA replication, when resolved improperly, may lead to deletions. In addition, single base pair substitution and insertion/deletion were also detected in the mutant clones. Taken together, our results indicated that BLM function is important in preventing small scale genetic alterations. Thus, both large scale and small scale genetic alterations are elevated when BLM is reduced, which may contribute to loss of function of tumor suppressor genes and subsequent tumorigenesis. 相似文献
139.
Dedova IV Nikolaeva OP Mikhailova VV dos Remedios CG Levitsky DI 《Biophysical chemistry》2004,110(1-2):119-128
Differential scanning calorimetry was used to examine the effects of cofilin on the thermal unfolding of actin. Stoichiometric binding increases the thermal stability of both G- and F-actin but at sub-saturating concentrations cofilin destabilizes F-actin. At actin:cofilin molar ratios of 1.5-6 the peaks corresponding to stabilized (66-67 degrees C) and destabilized (56-57 degrees C) F-actin are observed simultaneously in the same thermogram. Destabilizing effects of sub-saturating cofilin are highly cooperative and are observed at actin:cofilin molar ratios as low as 100:1. These effects are abolished by the addition of phalloidin or aluminum fluoride. Conversely, at saturating concentrations, cofilin prevents the stabilizing effects of phalloidin and aluminum fluoride on the F-actin thermal unfolding. These results suggest that cofilin stabilizes those actin subunits to which it directly binds, but destabilizes F-actin with a high cooperativity in neighboring cofilin-free regions. 相似文献
140.
Sevostyanova IA Solovjeva ON Kochetov GA 《Biochemical and biophysical research communications》2004,313(3):771-774
Yeast transketolase, in addition to catalyzing the transferase reaction through utilization of two substrates--the donor substrate (ketose) and the acceptor substrate (aldose)--is also able to catalyze a one-substrate reaction with only aldose (glycolaldehyde) as substrate. The interaction of glycolaldehyde with holotransketolase results in formation of the transketolase reaction intermediate, dihydroxyethyl-thiamin diphosphate. Then the glycolaldehyde residue is transferred from dihydroxyethyl-thiamin diphosphate to free glycolaldehyde. As a result, the one-substrate transketolase reaction product, erythrulose, is formed. The specific activity of transketolase was found to be 0.23 U/mg and the apparent Km for glycolaldehyde was estimated as 140 mM. 相似文献