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排序方式: 共有195条查询结果,搜索用时 8 毫秒
51.
J Steinbuch AC van Dijk FHBM Schreuder MTB Truijman J Hendrikse PJ Nederkoorn A van der Lugt E Hermeling APG Hoeks WH Mess 《Cardiovascular ultrasound》2017,15(1):9
Background
Mean or maximal intima-media thickness (IMT) is commonly used as surrogate endpoint in intervention studies. However, the effect of normalization by surrounding or median IMT or by diameter is unknown. In addition, it is unclear whether IMT inhomogeneity is a useful predictor beyond common wall parameters like maximal wall thickness, either absolute or normalized to IMT or lumen size. We investigated the interrelationship of common carotid artery (CCA) thickness parameters and their association with the ipsilateral internal carotid artery (ICA) stenosis degree.Methods
CCA thickness parameters were extracted by edge detection applied to ultrasound B-mode recordings of 240 patients. Degree of ICA stenosis was determined from CT angiography.Results
Normalization of maximal CCA wall thickness to median IMT leads to large variations. Higher CCA thickness parameter values are associated with a higher degree of ipsilateral ICA stenosis (p?<?0.001), though IMT inhomogeneity does not provide extra information. When the ratio of wall thickness and diameter instead of absolute maximal wall thickness is used as risk marker for having moderate ipsilateral ICA stenosis (>50%), 55 arteries (15%) are reclassified to another risk category.Conclusions
It is more reasonable to normalize maximal wall thickness to end-diastolic diameter rather than to IMT, affecting risk classification and suggesting modification of the Mannheim criteria.Trial registration
Clinical trials.gov NCT01208025.52.
Robles-Hernández L J Hernández-Huerta AC González-Franco OA Hernández-Rodríguez A Núñez-Barrios R Pérez-Leal 《Phyton》2015,84(2):253-261
Chili pepper is one of the main crops of economic importance in Mexico, and Fusarium wilting is a disease that limits its production. In addition, the inappropriate use of agrochemicals in farming activities generate environmental and health problems. Therefore, in this study the effectiveness of Streptomyces sp PRIO41 was evaluated as a (1) biocontrol agent of Fusarium spp and (2) plant growth promoter bacteria. Assays of pathogenicity and virulence of Fusarium spp. in jalapeño pepper seeds, and interactions of these pathogens with Streptomyces PRIO41 were evaluated under two nutritional conditions. In the greenhouse, the effectiveness of Streptomyces sp. PRIO41 was determined as a (1) biocontrol of Fusarium, and (2) plant growth promoter of wilt of pepper plants. The results showed that all fungal isolates caused symptoms in pepper seeds and seedlings with different degrees of virulence. Interactions in vitro showed that Streptomyces showed the most effective range of virulence against Fusarium isolates in the poor medium (37.6%-100%), with fungicidal effects in some cases. In the greenhouse, Streptomyces PRIO41 reduced Fusarium wilting up to a 40%, and positively affected all vegetative growth parameters, particularly plant height, leaf area, root length, and leaf and root dry biomasses. This study showed the potential of Streptomyces PRIO41 as a biocontrol agent of Fusarium spp., and as a biofertilizer of pepper plants. 相似文献
53.
Veronica Vinciotti Xiaohui Liu Rolf Turk Emile J de Meijer Peter AC 't Hoen 《BMC bioinformatics》2006,7(1):183-12
Background
The identification of biologically interesting genes in a temporal expression profiling dataset is challenging and complicated by high levels of experimental noise. Most statistical methods used in the literature do not fully exploit the temporal ordering in the dataset and are not suited to the case where temporal profiles are measured for a number of different biological conditions. We present a statistical test that makes explicit use of the temporal order in the data by fitting polynomial functions to the temporal profile of each gene and for each biological condition. A Hotelling T 2-statistic is derived to detect the genes for which the parameters of these polynomials are significantly different from each other. 相似文献54.
A covariotide model explains apparent phylogenetic structure of oxygenic photosynthetic lineages 总被引:17,自引:13,他引:4
Lockhart PJ; Steel MA; Barbrook AC; Huson DH; Charleston MA; Howe CJ 《Molecular biology and evolution》1998,15(9):1183-1188
The aims of the work were (1) to develop statistical tests to identify
whether substitution takes place under a covariotide model in sequences
used for phylogenetic inference and (2) to determine the influence of
covariotide substitution on phylogenetic trees inferred for photosynthetic
and other organisms. (Covariotide and covarion models are ones in which
sites that are variable in some parts of the underlying tree are invariable
in others and vice versa.) Two tests were developed. The first was a
contingency test, and the second was an inequality test comparing the
expected number of variable sites in two groups with the observed number.
Application of these tests to 16S rDNA and tufA sequences from a range of
nonphotosynthetic prokaryotes and oxygenic photosynthetic prokaryotes and
eukaryotes suggests the occurrence of a covariotide mechanism. The degree
of support for partitioning of taxa in reconstructed trees involving these
organisms was determined in the presence or absence of sites showing
particular substitution patterns. This analysis showed that the support for
splits between (1) photosynthetic eukaryotes and prokaryotes and (2)
photosynthetic and nonphotosynthetic organisms could be accounted for by
patterns arising from covariotide substitution. We show that the additional
problem of compositional bias in sequence data needs to be considered in
the context of patterns of covariotide/covarion substitution. We argue that
while covariotide or covarion substitution may give rise to
phylogenetically informative patterns in sequence data, this may not always
be so.
相似文献
55.
Water stress and root formation in pea cuttings 总被引:1,自引:0,他引:1
The stock plants of pea (Pistum sativium L. cv. Alaska) grown for 11 days at 16 W m?2 38 W m?2 were subjected to different degrees of moisture stress, simulated with polyethyleneglycol (PEG, 6000) for different periods. The cuttings were made at the end of stress treatments, planted in perlite and allowed to root in a mist propagation chamber. The number of adventitious roots formed on the cuttings from non-stressed plants was significantly higher under low (16 W m?2) than under high (38 W m?2) irradiance. However, under the influence of short duration stress the number of roots increased significantly under high but not under low irradiance. There was significantly poor rooting after prolonged stress under both irradiances. The leaf osmotic potential ψπ showed a greater reduction with increasing degree and duration of stress at 38 W m?2 than at 16 W m?2. The differential rooting behaviour as a result of stress levels and irradiances is discussed in the light of available literature on adventitious root formation. 相似文献
56.
Stock plants of pea (Pisum sativum L. cv. Alaska) were grown at different controlled levels of irradiance (4, 16 or 38 W m?2) for 11 days from sowing. Morphactin (CFM, methyl-2-chloro-9-hydroxy-fluorene-9-carboxylate) was applied to the apex of the stock plants 3 days before cuttings were excised. The cuttings were rooted at 16 W m?2. High levels of morphactin (>5 × 10?3 mg l?1) inhibited root formation in the cuttings. Low concentrations of CFM (5 × 10?5 mg l?1) promoted the formation of adventitious roots in cuttings from plants grown at all three levels of irradiance, with the most pronounced effect in cuttings from 4 W m?2. Measurements of ethylene evolution by CFM-treated plants 3 days after application, revealed a stimulatory effect on ethylene production by high CFM concentrations. 相似文献
57.
Data from population- and clinic-based epidemiologic studies of rheumatoid arthritis patients suggest that individuals with
rheumatoid arthritis are at risk for developing clinically evident congestive heart failure. Many established risk factors
for congestive heart failure are over-represented in rheumatoid arthritis and likely account for some of the increased risk
observed. In particular, data from animal models of cytokine-induced congestive heart failure have implicated the same inflammatory
cytokines produced in abundance by rheumatoid synovium as the driving force behind maladaptive processes in the myocardium
leading to congestive heart failure. At present, however, the direct effects of inflammatory cytokines (and rheumatoid arthritis
therapies) on the myocardia of rheumatoid arthritis patients are incompletely understood. 相似文献
58.
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60.
Determinants of Readiness for Adopting Healthy Lifestyle Behaviors Among Indigenous Adolescents with Type 2 Diabetes in Manitoba,Canada: A Cross‐Sectional Study 下载免费PDF全文