236 research outputs found

    Statistical Spectral Characteristics of Three-Dimensional Winds in the Mesopause Region Revealed by the Andes Lidar

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    By analyzing data recorded at the Andes Lidar Observatory in Cerro Pachon, Chile (30.3Β°S, 70.7Β°W) from May 2014 to July 2019, we investigated the fundamental features of three-dimensional wind and temperature spectra. The vertical wavenumber spectral amplitudes of horizontal winds show obvious seasonal variations that are closely related to the seasonal variations in the source and background winds. The wavenumber spectral slopes of the horizontal winds are systematically less negative than βˆ’3, with mean values of βˆ’1.96 and βˆ’2.18 for zonal and meridional winds, respectively. The zonal and meridional wind frequency spectra have mean slopes of βˆ’1.37 and βˆ’1.56, respectively; these values are slightly less negative than βˆ’5/3. Moreover, the frequency spectral amplitudes show different seasonal variations from those of the wavenumber spectra, possibly because they correspond to different GW spectral components. The vertical wind has obviously different spectral features than the horizontal winds. The vertical wind spectra are notably shallower than the horizontal wind spectra, with mean slopes of βˆ’0.82 and βˆ’0.91 for the wavenumber and frequency spectra, respectively, departing evidently from those expected under linear instability theory (LIT). Although the vertical wind spectrum is almost always separable, the horizontal wind spectra are separable only at high frequencies. As the frequency increased, the horizontal wind wavenumber spectra become shallower and depart from the spectral slope expected under LIT, likely because high-frequency GWs are not completely saturated. In general, our results do not support LIT

    Particulate air pollution, systemic oxidative stress, inflammation, and atherosclerosis

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    Air pollution has been associated with significant adverse health effects leading to increased overall morbidity and mortality of worldwide significance. Epidemiological studies have shown that the largest portion of air pollution-related mortality is due to cardiovascular diseases, predominantly those of ischemic nature. Human studies suggest an association with atherosclerosis and increasing experimental animal data support that this association is likely to be causal. While both gasses and particles have been linked to detrimental health effects, more evidence implicates the particulate matter (PM) components as major responsible for a large portion of the proatherogenic effects. Multiple experimental approaches have revealed the ability of PM components to trigger and/or enhance free radical reactions in cells and tissues, both ex vivo as well as in vivo. It appears that exposure to PM leads to the development of systemic prooxidant and proinflammatory effects that may be of great importance in the development of atherosclerotic lesions. This article reviews the epidemiological studies, experimental animal, and cellular data that support the association of air pollutants, especially the particulate components, with systemic oxidative stress, inflammation, and atherosclerosis. It also reviews the use of transcriptomic studies to elucidate molecular pathways of importance in those systemic effects

    Great Genetic Differentiation among Populations of Meconopsis integrifolia and Its Implication for Plant Speciation in the Qinghai-Tibetan Plateau

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    The complex tectonic events and climatic oscillations in the Qinghai-Tibetan Plateau (QTP), the largest and highest plateau in the world, are thought to have had great effects on the evolutionary history of the native plants. Of great interest is to investigate plant population genetic divergence in the QTP and its correlation with the geologic and climatic changes. We conducted a range-wide phylogeographical analysis of M. integrifolia based on the chloroplast DNA (cpDNA) trnL-trnF and trnfM-trnS regions, and defined 26 haplotypes that were phylogenetically divided into six clades dated to the late Tertiary. The six clades correspond, respectively, to highly differentiated population groups that do not overlap in geographic distribution, implying that the mountain ranges acting as corridors or barriers greatly affected the evolutionary history of the QTP plants. The older clade of M. integrifolia only occurs in the southwest of the species' range, whereas the distributions of younger clades extend northeastward in the eastern QTP, suggesting that climatic divergence resulting from the uplift of the QTP triggered the initial divergence of M. integrifolia native to the plateau. Also, the nrDNA ITS region was used to clarify the unexpected phylogenetic relationships of cpDNA haplotypes between M. integrifolia and M. betonicifolia. The topological incongruence between the two phylogenies suggests an ancestral hybridization between the two species. Our study indicates that geographic isolation and hybridization are two important mechanisms responsible for the population differentiation and speciation of Meconopsis, a species-rich genus with complex polyploids

    RET Germline Mutations Identified by Exome Sequencing in a Chinese Multiple Endocrine Neoplasia Type 2A/Familial Medullary Thyroid Carcinoma Family

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    BACKGROUND: Whole exome sequencing provides a labor-saving and direct means of genetic diagnosis of hereditary disorders in which the pathogenic gene harbors a large cohort of exons. We set out to demonstrate a suitable example of genetic diagnosis of MEN 2A/FMTC (multiple endocrine neoplasia type 2/familial medullary thyroid carcinoma) using this approach. METHODOLOGY/PRINCIPAL FINDINGS: We sequenced the whole exome of six individuals from a large Chinese MEN2A/FMTC pedigree to identify the variants of the RET (REarranged during Transfection) protooncogene and followed this by validation. Then prophylactic or surgical thyroidectomy with modified or level VI lymph node dissection and adrenalectomy were performed for the carriers. The cases were closely followed up. Massively parallel sequencing revealed four missense mutations of RET. We unexpectedly discovered that the proband's daughter with MEN 2A-related MTC presented a novel p.C634Y/V292M/R67H/R982C compound mutation, due to the involvement of p.C634Y in the proband with MEN 2A and p.V292M/R67H/R982C in the proband's husband with FMTC. In the maternal origin, p.C634Y caused bilateral MTC in all 5 cases and bilateral pheochromocytoma in 2 of the 5; the earliest onset age was 28 years. In the paternal origin, one of the six p.V292M/R67H/R982C carriers presented bilateral MTC (70 years old), one only had bilateral C-cell hyperplasia (44 years), two had bilateral multi-nodules (46 and 48 years) and two showed no abnormality (22 and 19 years). CONCLUSIONS/SIGNIFICANCE: The results confirmed the successful clinical utility of whole exome sequencing, and our data suggested that the p.C634Y/V292M/R67H/R982C mutation of RET exhibited a more aggressive clinical phenotype than p.C634Y or p.V292M/R67H/R982C, while p.V292M/R67H/R982C presented a relatively milder pathogenicity of MTC and likely predisposed to FMTC

    Polymorphisms of βˆ’174G>C and βˆ’572G>C in the Interleukin 6 (IL-6) Gene and Coronary Heart Disease Risk: A Meta-Analysis of 27 Research Studies

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    OBJECTIVE: Elevated serum IL-6 level is a risk factor for coronary heart disease (CHD). The -174 G>C and -572 G>C polymorphisms in the IL-6 gene have previously been shown to modulate IL-6 levels. But the association between the -174 G>C and -572 G>C polymorphisms and the risk of CHD is still unclear. A meta-analysis of all eligible studies was carried out to clarify the role of IL-6 gene polymorphisms in CHD. METHODS AND RESULTS: PubMed, EMBASE, Vip, CNKI and CBM-disc were searched for eligible articles in English and Chinese that were published before October 2010. 27 studies involving 11580 patients with CHD and 17103 controls were included. A meta-analysis was performed for the included articles using the RevMan 5.0 and Stata 10.0 softwares. Overall, the -174 C allele was not significantly associated with CHD risk (ORs = 1.04, 95%CI = 0.98 to 1.10) when compared with the -174 G allele in the additive model, and meta-analysis under other genetic models (dominant, recessive, CC versus GG, and GC versus GG) also did not reveal any significant association. On the contrary, the -572 C allele was associated with a decreased risk of CHD when compared with the -572 G allele (ORs = 0.79, 95%CI = 0.68 to 0.93). Furthermore, analyses under the recessive model (ORs = 0.69, 95% = 0.59 to 0.80) and the allele contrast model (genotype of CC versus GG, ORs = 0.49, 95% = 0.35 to 0.70) yielded similar results. However, statistical significance was not found when the meta-analysis was restricted to studies focusing on European populations, studies with large sample size, and cohort studies by using subgroup analysis. CONCLUSIONS: The -174 G>C polymorphism in the IL-6 gene is not significantly associated with increased risks of CHD. However, The -572 G>C polymorphism may contribute to CHD development. Future investigations with better study design and large number of subjects are needed
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