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Latter Groups (latter + groups)
Selected AbstractsTransient thermal modelling of heat recovery steam generators in combined cycle power plantsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 11 2007Sepehr Sanaye Abstract Heat recovery steam generator (HRSG) is a major component of a combined cycle power plant (CCPP). This equipment is particularly subject to severe thermal stress especially during cold start-up period. Hence, it is important to predict the operational parameters of HRSGs such as temperature of steam, water, hot gas and tube metal of heating elements as well as pressure change in drums during transient and steady-state operation. These parameters may be used for estimating thermal and mechanical stresses which are important in HRSG design and operation. In this paper, the results of a developed thermal model for predicting the working conditions of HRSG elements during transient and steady-state operations are reported. The model is capable of analysing arbitrary number of pressure levels and any number of elements such as superheater, evaporator, economizer, deaerator, desuperheater, reheater, as well as duct burners. To assess the correct performance of the developed model two kinds of data verification were performed. In the first kind of data verification, the program output was compared with the measured data collected from a cold start-up of an HRSG at Tehran CCPP. The variations of gas, water/steam and metal temperatures at various sections of HRSG, and pressure in drums were among the studied parameters. Mean differences of about 3.8% for temperature and about 9.2% for pressure were observed in this data comparison. In the second kind of data verification, the steady-state numerical output of the model was checked with the output of the well-known commercial software. An average difference of about 1.5% was found between the two latter groups of data. Copyright © 2007 John Wiley & Sons, Ltd. [source] Configurational assignments of the diastereomers of 3,3,-(1,2-ethanediyl)bis[2-(3-fluorophenyl)-5-methyl-4-thiazolidinone] derivative with four stereogenic centersJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 2 2001Maria Gabriella Vigorita Diastereomers of antiinflammatory/analgesic and antihistaminic 3,3,[(1,2-ethanediyl)bis(2-aryl-4-thiazo-lidinone)] derivatives possessing two stereogenic centers (indicated as BIS 2*C) have been widely investigated in recent years. The 5,5,-dimethyl analogues (BIS 4*C), now reported, have been synthesized by reaction of (±) ,-mercaptopropionic acid and N,N' -di(3-fluorobenzyliden)ethylenediamine. Because the 2 and 2,carbons bear the same groups and similarly the 5 and 5, carbons, and the latter groups are different from the former, four enantiomeric pairs and two meso forms exist in this situation. These diastereomers were identified by the concerted use of nmr spectroscopy and hplc on chiral stationary phase. [source] Seroprevalence of Kaposi's sarcoma-associated herpesvirus and risk factors in Xinjiang, China,JOURNAL OF MEDICAL VIROLOGY, Issue 8 2009Bishi Fu Abstract Xinjiang, China is an endemic area for Kaposi's sarcoma (KS) but the seroprevalence of Kaposi's sarcoma-associated herpesvirus (KSHV) and risk factors remain undefined. In this study, antibodies to one KSHV latent protein (ORF73) and two KSHV lytic proteins (ORF65 and ORF-K8.1) were examined in 2,228 subjects from the general population and 37 subjects infected with HIV-1 in Xinjiang, and 560 subjects from the general population in Hubei, a low KS incidence region. The serostatus of a serum sample was defined based on positive results in any one of the three serologic assays. The seroprevalence of KSHV in the general population was higher in Xinjiang than in Hubei (19.2% vs. 9.5%; odds ratios [OR], 2.28; 95% confidence interval [CI], 1.68,3.08; P,<,0.001). Among the ethnic groups in Xinjiang, 68 (15.8%) Han, 182 (20.7%) Uygur, 140 (19.9%) Hazakh, 9 (33.3%) Xibo, and 29 (16.8%) Hui were KSHV-seropositive, respectively. Compared to the Han, the latter groups had an increase in the risk of KSHV of 62.2%, 63.8%, 180.1%, and 30.2% (P,=,0.003, 0.004, 0.018, and 0.286, respectively). Subjects aged <20, 20,50, and >50 had a seroprevalence of KSHV of 11.8%, 17.9%, and 24.6%, respectively. Compared to subjects aged <20, the latter groups had an increase in the risk of KSHV of 63.3% and 144.5% (P,=,0.009 and <0.001, respectively). Subjects infected with HIV-1 in Xinjiang had a seroprevalence of KSHV of 43.2%, and a 220% increase in the risk of KSHV compared to the general population (P,<,0.001). Similar results were obtained when the seroprevalence of KSHV was analyzed with any single or two of the three serologic assays alone. Genotyping identified three unique sequences clustered in the A clade. This study indicates that Xinjiang has a high seroprevalence of KSHV. Geographic location, ethnicity, age and HIV-1 infection are risk factors. Serologic and genotyping results suggest the introduction of KSHV into Xinjiang by specific ethnic groups. J. Med. Virol. 81:1422,1431, 2009. © 2009 Wiley-Liss, Inc. [source] Long-term infection with Helicobacter felis and inactivation of the tumour suppressor gene p53 cumulatively enhance the gastric mutation frequency in Big Blue® transgenic miceTHE JOURNAL OF PATHOLOGY, Issue 4 2003Peter J Jenks Abstract The aims of this study were to determine whether colonization with Helicobacter felis resulted in the accumulation of mutations within murine gastric tissue and whether the degree of genetic damage was increased by p53 deficiency. Female C57BL/6 mice carrying either the lambda/lacI transgene (Big Blue® transgenic mice) or the lambda/lacI transgene and deficient in one allele of the p53 tumour suppressor gene (TSG-p53®/Big Blue®) were inoculated with H felis. Seven months after inoculation, mutations in the target lacI gene were assessed using the Big Blue® transgenic mutagenesis assay system in these animals and in controls. There was an approximately two-fold increase in lacI mutations in gastric mucosa harvested from mice infected with H felis and also from non-infected mice heterozygous for the p53 allele relative to wild-type mice. The mutation frequency in mice infected with H felis and deficient in one allele of p53 was increased approximately three-fold. Active gastric inflammation was significantly greater in H felis -infected p53 hemizygous mice compared with H felis p53 wild-type mice. Gastric epithelial proliferation was similarly increased with infection in both of these latter groups of mice. In infected mice, there was a significant correlation between the mutation frequency and the degree of active gastric inflammation. These data suggest a synergistic action between infection with H felis and p53 deficiency in the accumulation of mutations within gastric tissue. Active neutrophil infiltration in gastric Helicobacter infection may contribute to the increased levels of mutation observed. Copyright © 2003 John Wiley & Sons, Ltd. [source] Lung transplantation in scleroderma compared with idiopathic pulmonary fibrosis and idiopathic pulmonary arterial hypertensionARTHRITIS & RHEUMATISM, Issue 12 2006Lionel Schachna Objective Lung transplantation is a viable, life-saving intervention for several primary pulmonary disorders complicated by severe lung dysfunction. This study was undertaken to evaluate whether patients with systemic sclerosis (scleroderma), a systemic autoimmune rheumatic disorder, would receive similar benefit from this intervention. Methods Survival following lung transplantation was examined at 2 university medical centers among 29 patients with scleroderma as compared with 70 patients with idiopathic pulmonary fibrosis (IPF) and 38 with idiopathic pulmonary arterial hypertension (IPAH), the latter groups representing pathologically related primary pulmonary disorders. The end point was death from any cause. Risk of mortality in patients with scleroderma was compared with that in patients with IPF or IPAH, with adjustment for demographic and clinical parameters. Results During 2 years of followup, 11 patients with scleroderma (38%), 23 with IPF (33%), and 14 with IPAH (37%) died. Cumulative survival at 6 months posttransplantation was 69% in the scleroderma group compared with 80% in the IPF group (log-rank P = 0.21) and 79% in the IPAH group (P = 0.38). The estimated risk of mortality at 6 months was increased in patients with scleroderma compared with those with IPF (relative risk [RR] 1.70, 95% confidence interval [95% CI] 0.74,3.93) and those with IPAH (RR 1.52, 95% CI 0.59,3.96), but the differences were not statistically significant. Over the following 18 months, there was convergence in the survival rates such that cumulative survival at 2 years was comparable, at ,64%, among all 3 groups. Conclusion Patients with scleroderma who are recipients of lung transplantation experience similar rates of survival 2 years after the procedure compared with those with IPF or IPAH. Lung transplantation may represent a viable therapeutic option to consider for patients with end-stage lung disease due to scleroderma. [source] | ||||||||||