985 resultados para Variable-chromosome-length
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Evaluating the length of time required to dry hardwood timber using vacuum drying compared to conventional drying facilities and technology.
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Telomere length (TL) has been associated with aging and mortality, but individual differences are also influenced by genetic factors, with previous studies reporting heritability estimates ranging from 34 to 82%. Here we investigate the heritability, mode of inheritance and the influence of parental age at birth on TL in six large, independent cohort studies with a total of 19 713 participants. The meta-analysis estimate of TL heritability was 0.70 (95% CI 0.64–0.76) and is based on a pattern of results that is highly similar for twins and other family members. We observed a stronger mother–offspring (r=0.42; P-value=3.60 × 10−61) than father–offspring correlation (r=0.33; P-value=7.01 × 10−5), and a significant positive association with paternal age at offspring birth (β=0.005; P-value=7.01 × 10−5). Interestingly, a significant and quite substantial correlation in TL between spouses (r=0.25; P-value=2.82 × 10−30) was seen, which appeared stronger in older spouse pairs (mean age ≥55 years; r=0.31; P-value=4.27 × 10−23) than in younger pairs (mean age<55 years; r=0.20; P-value=3.24 × 10−10). In summary, we find a high and very consistent heritability estimate for TL, evidence for a maternal inheritance component and a positive association with paternal age.
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OBJECTIVE To refine a previously reported linkage peak for endometriosis on chromosome 10q26, and conduct follow-up analyses and a fine-mapping association study across the region to identify new candidate genes for endometriosis. DESIGN Case-control study. SETTING Academic research. PATIENT(S) Cases=3,223 women with surgically confirmed endometriosis; controls=1,190 women without endometriosis and 7,060 population samples. INTERVENTION(S) Analysis of 11,984 single nucleotide polymorphisms on chromosome 10. MAIN OUTCOME MEASURE(S) Allele frequency differences between cases and controls. RESULT(S) Linkage analyses on families grouped by endometriosis symptoms (primarily subfertility) provided increased evidence for linkage (logarithm of odds score=3.62) near a previously reported linkage peak. Three independent association signals were found at 96.59 Mb (rs11592737), 105.63 Mb (rs1253130), and 124.25 Mb (rs2250804). Analyses including only samples from linkage families supported the association at all three regions. However, only rs11592737 in the cytochrome P450 subfamily C (CYP2C19) gene was replicated in an independent sample of 2,079 cases and 7,060 population controls. CONCLUSION(S) The role of the CYP2C19 gene in conferring risk for endometriosis warrants further investigation.
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Work with consultants to help graziers understand implications of carbon in their pastures.
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Alamethicin, its derivatives and some synthetic fragments have been shown to be uncouplers of oxidative phosphorylation in rat liver mitochondria. A minimum peptide chain length of 13 residues is necessary for this activity. Peptide esters are more efficient uncouplers than the corresponding peptide acids. Esterification of the Glu(18) γ-COOH group in alamethicin does not diminish uncoupling activity. The structural requirements for uncoupling activity parallel those determined for ionophoretic action in small, unilamellar liposomes. Aib, α-aminoisobutyric acid; Z, benzyloxycarbonyl; OMe, methyl ester; OBz, benzyl ester; Ac, acetyl; CTC, chlortetracycline.
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The ratio of the lengths of an individual's second to fourth digit (2D:4D) is commonly used as a noninvasive retrospective biomarker for prenatal androgen exposure. In order to identify the genetic determinants of 2D:4D, we applied a genome-wide association approach to 1507 11-year-old children from the Avon Longitudinal Study of Parents and Children (ALSPAC) in whom 2D:4D ratio had been measured, as well as a sample of 1382 12- to 16-year-olds from the Brisbane Adolescent Twin Study. A meta-analysis of the two scans identified a single variant in the LIN28B gene that was strongly associated with 2D:4D (rs314277: p = 4.1 x 10(-8)) and was subsequently independently replicated in an additional 3659 children from the ALSPAC cohort (p = 1.53 x 10(-6)). The minor allele of the rs314277 variant has previously been linked to increased height and delayed age at menarche, but in our study it was associated with increased 2D:4D in the direction opposite to that of previous reports on the correlation between 2D:4D and age at menarche. Our findings call into question the validity of 2D:4D as a simplistic retrospective biomarker for prenatal testosterone exposure.
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This paper reports an experimental investigation carried out, using the photoelastic technique, to determine the Mode I stress intensity factor in case of cracks of varying a/w ratio in single edge-notch specimens. The photoelastic information was analysed using the several methods proposed by earlier workers. The experimental results are compared with the analytical expressions.
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OBJECTIVE: The study of ethnically homogeneous populations may help to identify schizophrenia risk loci. The authors conducted a genomewide linkage scan for schizophrenia in an Indian population. METHOD: Participants were 441 individuals (262 affected probands and siblings) who were recruited primarily from one ethnically homogeneous group, the Tamil Brahmin caste, although individuals from other geographically proximal castes also participated. Genotyping of 124 affected sibling pair pedigrees was performed with 402 short tandem repeat polymorphisms. Linkage analyses were conducted using nonparametric exponential LOD (logarithm of the odds ratio for linkage) scores and parametric heterogeneity LOD scores. Parametric heterogeneity scores were calculated using simple dominant and recessive models, correcting for multiple statistics. The data were examined for evidence of consanguinity. Genomewide significance levels were determined using 10,000 gene dropping simulations. RESULTS: These findings revealed genomewide significant linkage to chromosome 1p31.1, through the use of both exponential and heterogeneity LOD scores, incorporating correction for multiple statistics and mild consanguinity. The estimated sibling recurrence risk associated with this putative locus was 1.95. Analysis for heterogeneity LOD scores also detected suggestive linkage to chromosomes 13q22.1 and 16q12.2. Using 117 tag single nucleotide polymorphisms (SNPs), family-based association analyses of phosphodiesterase 4B (PDE4B), the closest schizophrenia candidate gene, detected no convincing evidence of association, suggesting that the chromosome 1 peak represents a novel risk locus. CONCLUSIONS: This is the first study-to the authors' knowledge-to report significant linkage of schizophrenia to chromosome 1p31.1. Further investigation of this chromosome region in diverse populations is warranted to identify underlying sequence variants.
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Context: Identifying susceptibility genes for schizophrenia may be complicated by phenotypic heterogeneity, with some evidence suggesting that phenotypic heterogeneity reflects genetic heterogeneity. Objective: To evaluate the heritability and conduct genetic linkage analyses of empirically derived, clinically homogeneous schizophrenia subtypes. Design: Latent class and linkage analysis. Setting: Taiwanese field research centers. Participants: The latent class analysis included 1236 Han Chinese individuals with DSM-IV schizophrenia. These individuals were members of a large affected-sibling-pair sample of schizophrenia (606 ascertained families), original linkage analyses of which detected a maximum logarithm of odds (LOD) of 1.8 (z = 2.88) on chromosome 10q22.3. Main Outcome Measures: Multipoint exponential LOD scores by latent class assignment and parametric heterogeneity LOD scores. Results: Latent class analyses identified 4 classes, with 2 demonstrating familial aggregation. The first (LC2) described a group with severe negative symptoms, disorganization, and pronounced functional impairment, resembling “deficit schizophrenia.” The second (LC3) described a group with minimal functional impairment, mild or absent negative symptoms, and low disorganization. Using the negative/deficit subtype, we detected genome-wide significant linkage to 1q23-25 (LOD = 3.78, empiric genome-wide P = .01). This region was not detected using the DSM-IV schizophrenia diagnosis, but has been strongly implicated in schizophrenia pathogenesis by previous linkage and association studies.Variants in the 1q region may specifically increase risk for a negative/deficit schizophrenia subtype. Alternatively, these results may reflect increased familiality/heritability of the negative class, the presence of multiple 1q schizophrenia risk genes, or a pleiotropic 1q risk locus or loci, with stronger genotype-phenotype correlation with negative/deficit symptoms. Using the second familial latent class, we identified nominally significant linkage to the original 10q peak region. Conclusion: Genetic analyses of heritable, homogeneous phenotypes may improve the power of linkage and association studies of schizophrenia and thus have relevance to the design and analysis of genome-wide association studies.
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Report on evidence of shrinkage of live coral trout during professional fishing operations on the Great Barrier Reef in 2000. Excel data includes the following fields: Column A. Fish (fish number from 1 -24) Column B. Bin (1-8, container the fish was held in during the experiment) Column C. Measure (1-7, number of the measurement of each fish) Column D. Observer (1 or 2, making the measurement) Column E. Time 2 Column F. Time (time of the day the measurement was made) Column G. FL (Fork Length) Column H. TL (Total Length) Column I. Difference (difference in length between measures) Column J. Order Column K. Temperature (surface water temp under the boat)
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Human central nervous system (CNS) tumors are a heterogeneous group of tumors occurring in brain, brainstem and spinal cord. Malignant gliomas (astrocytic and oligodendroglial tumors), which arise from the neuroepithelial cells are the most common CNS neoplasms in human. Malignant gliomas are highly aggressive and invasive tumors, and have a very poor prognosis. The development and progression of gliomas involve a stepwise accumulation of genetic alterations that generally affect either signal transduction pathways activated by receptor tyrosine kinases (RTKs), or cell cycle arrest pathways. Constitutive activation or deregulated signaling by RTKs is caused by gene amplification, overexpression or mutations. The aberrant RTK signaling results in turn in the activation of several downstream pathways, which ultimately lead to malignant transformation and tumor proliferation. Many genetic abnormalities implicated in nervous system tumors involve the genes located at the chromosomal region 4q12. This locus harbors the receptor tyrosine kinases KIT, PDGFRA and VEGFR2, and other genes (REST, LNX1) with neural function. Gene amplification and protein expression of KIT, PDGFRA, and VEGFR2 was studied using clinical tumor material. REST and LNX1, as well as NUMBL, the interaction partner of LNX1, were studied for their gene mutations and amplifications. In our studies, amplification of LNX1 was associated with KIT and PDGFRA amplification in glioblastomas, and coamplification of KIT, PDGFRA and VEGFR2 was detected in medulloblastomas and CNS primitive neuroectodermal tumors. PDGFRA amplification was also correlated with poor overall survival. Coamplification of KIT, PDGFRA and VEGFR2 was observed in a subset of human astrocytic and oligodendroglial tumors. We suggest that genes at 4q12 could be a part of a larger amplified region, which is deregulated in gliomas, and could be used as a prognostic marker of tumorigenic process. The signaling pathways activated due to gene amplifications, activating gene mutations, and overexpressed proteins may be useful as therapeutic targets for glioma treatment. This study also includes the characterization of KIT overexpressing astrocytes, analyzed by various in vitro functional assays. Our results show that overexpression of KIT in mouse astrocytes promotes cell proliferation and anchorage-independent growth, as well as phenotypic changes in the cells. Furthermore, the increased proliferation is partly inhibited by imatinib, a small molecule inhibitor of KIT. These results suggest that KIT may play a role in astrocyte growth regulation, and might have an oncogenic role in brain tumorigenesis. Elucidation of the altered signaling pathways due to specific gene amplifications, activating gene mutations, and overexpressed proteins may be useful as therapeutic targets for glioma treatment.
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The review of existing information has identified the following: - the juvenile core in Araucaria is probably contained within the first 15 growth rings in the pith, with spiral grain being a chief determinant of its extent within the stem; - a reduction in rotation length for a given site index will reduce ASV and mature wood volume, with an increase in the proportion of juvenile wood; - for a given rotation length, lower ASV stems were estimated to contain a lower proportion of juvenile wood (based on the assumptions made and crude simulations using WEEDS, PL YSIM and STEPS software); regardless of juvenile wood proportions, smaller stems will yield a higher proportion of pith-in material; - an increase in the proportion of juvenile wood, due to a reduction in rotation length, could affect wood quality due to an increase in the proportion of the recovery containing high spiral grain, shorter tracheids and higher micellar angle; - high spiral grain and high micellar angles adversely impact on wood quality through their influence on twist and longitudinal shrinkage, respectively; - positive outcomes from a reduction in rotation length might include an increase in the proportion of live knots in upper stem sections and a reduction in the extent of brown-stain heartwood; - the uniformity in basic density within Araucaria stems means reduced rotation lengths and lower stem ASVs are unlikely to have a major impact on this wood property, and - the effect of a reduction in rotation length on the incidence of compression wood and timber susceptible to kiln staining could not be established from the available information.