677 research outputs found

    Chemical characterization and size distribution of atmospheric particles in urban area - preliminary study

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    The present work is a preliminary study with the aim of characterize the particle size and the chemical composition of aerosols in the Charqueadas County in Rio Grande do Sul State, Brazil, in order to better identify the sources responsible for alterations in the air quality. Seven filters were used for collecting material on thin nucleopore polycarbonate membrane (0,4 µm) during March/1996 to July/1996. X-ray energy dispersive scanning electron microscopy was used to determine the chemical composition of aerosol particles, and 21 elements were then analysed. Particle size distribution was measured by SEM-EDX analysis, and also by automated image technique. Nonhierarchical cluster analysis was applied to identify the types of particles present in the samples. This procedure resulted in the definition of 8 groups of particles containing Fe, Zn, Si, Al, S, Ca, Na and K, that revealed the chemical heterogeneity of aerosols in Charqueadas Country. The particle size analysis showed the predominance (around 80% of all analyzed particles) of the fraction ≤ 10 µm (dia) with the highest concentration of these particles located in the size ≤ 2.0 µm (dia). Data from particle size distribution, including Falk and Ward parameters, were combined with meteorological parameters and subjected to Hierarchical Cluster Analysis and Discriminant Analysis. This procedure allowed particle-based features and meteorological variables to be integrated for potentially better discriminant capability.O presente trabalho consiste em um estudo preliminar com o objetivo de caracterizar o tamanho de partícula e a composição elementar dos aerossóis no Município de Charqueadas no estado do Rio Grande do Sul, Brasil, a fim de identificar melhor as fontes que tem provocado alterações da qualidade do ar. Sete filtros foram coletados em membrana filtro de policarbonato (0,4 µm) no período de Março/96 à Julho/96. Microscopia eletrônica com energia dispersiva de Raio-X foi usado para caracterizar a composição elementar de aerossóis coletados em amostrador de ar. Distribuição de tamanho de partícula foi realizada aplicando além do SEM-EDX, a técnica analisador de imagem automático. Análise de Cluster não hierárquica foi aplicada para identificar os tipos de partículas. Estes dados resultaram na definição de 8 grupos de partículas contendo Fe, Zn, Si, AI, S, Ca, Na e K, revelando heterogeneidade química dos aerossóis no Município de Charqueadas. A distribuição granulométrica mostrou predominância de tamanho ≤ 10 µm, cerca de 80 % do total de partículas analisadas, sendo que o percentual mais elevado foi verificado na fração de 1 µm e 2 µm. Os dados de distribuição granulométrica, juntamente com as variáveis meteorológicas foram avaliados, aplicando Análise de Agrupamento Hierárquico, pelo método de Ward's, e Análise Discriminante. Este procedimento permitiu que as variáveis meteorológicas e as características das partículas fossem integradas para melhor capacidade discriminatória

    Comparative transcriptomics of human multipotent stem cells during adipogenesis and osteoblastogenesis

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    <p>Abstract</p> <p>Background</p> <p>A reciprocal relationship between bone and fat development in osteoporosis is clinically well established. Some of the key molecular regulators involved in this tissue replacement process have been identified. The detailed mechanisms governing the differentiation of mesenchymal stem cells (MSC) – the key cells involved – are however only now beginning to emerge. In an attempt to address the regulation of the adipocyte/osteoblast balance at the level of gene transcription in a comprehensive and unbiased manner, we performed a large-scale gene expression profiling study using a unique cellular model, human multipotent adipose tissue-derived stem cells (hMADS).</p> <p>Results</p> <p>The analysis of 1606 genes that were found to be differentially expressed between adipogenesis and osteoblastogenesis revealed gene repression to be most prevalent prior to commitment in both lineages. Computational analyses suggested that this gene repression is mediated by miRNAs. The transcriptional activation of lineage-specific molecular processes in both cases occurred predominantly after commitment. Analyses of the gene expression data and promoter sequences produced a set of 65 genes that are candidates for genes involved in the process of adipocyte/osteoblast commitment. Four of these genes were studied in more detail: <it>LXRα </it>and phospholipid transfer protein (<it>PLTP</it>) for adipogenesis, the nuclear receptor <it>COUP-TF1 </it>and one uncharacterized gene, <it>TMEM135 </it>for osteoblastogenesis. <it>PLTP </it>was secreted during both early and late time points of hMADS adipocyte differentiation. <it>LXRα</it>, <it>COUP-TF1</it>, and the transmembrane protein <it>TMEM135 </it>were studied in primary cultures of differentiating bone marrow stromal cells from healthy donors and were found to be transcriptionally activated in the corresponding lineages.</p> <p>Conclusion</p> <p>Our results reveal gene repression as a predominant early mechanism before final cell commitment. We were moreover able to identify 65 genes as candidates for genes controlling the adipocyte/osteoblast balance and to further evaluate four of these. Additional studies will explore the precise role of these candidate genes in regulating the adipogenesis/osteoblastogenesis switch.</p

    Neandertals and modern humans in Western Asia.

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    Edited by Takeru Akazawa, Kenichi Aoki, and Ofer Bar-Yosef. 1998. New York: Plenum Press. 552 pp. ISBN 0-306-45924-8. $79.50 (cloth).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34265/1/10_ftp.pd

    Effects of cranberry powder on serum lipid profiles and biomarkers of oxidative stress in rats fed an atherogenic diet

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    This study investigated that the antioxidative effect of freeze-dried cranberry powder against protein and lipid oxidation and ameliorative effect of serum lipid profile in rat fed atherogenic diet. Six weeks old male Sprague-Dawley rats were divided into the following four groups: normal diet group with 5% corn oil (control), atherogenic diet group with 5% corn oil, 10% lard, 1% cholesterol, and 0.5% sodium cholate (HFC), atherogenic plus 2% cranberry powder diet group (HFC + C2), and atherogenic plus 5% cranberry powder diet group (HFC + C5), and respective diet and water were fed daily for 6 weeks. After the experimental period, the serum lipid profile, such as total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglyceride, ferric reducing ability of plasma (FRAP), plasma phenolics content, superoxide dismutase (SOD) activity, serum protein carbonyl and thiobarbituric acid reactive substances (TBARS) levels were examined. Total phenolic compound and total flavonoid levels in freeze-dried cranberry powder were 9.94 mg/g and 8.12 mg/g, respectively. Serum total cholesterol and LDL-cholesterol levels were not significantly different for cranberry powder treatment, but serum HDL-cholesterol level was significantly increased in HFC + C5 group compared with HFC group. Plasma FRAP value tended to be increased by cranberry powder treatment though there was no significant difference. Plasma total phenol concentrations and SOD activities were not significantly different among all groups. Serum protein carbonyl and TBARS levels were significantly decreased in HFC + C5 group compared with HFC group. Overall results suggested that freeze-dried cranberry powder might have the serum lipid improving effect, as well as antioxidative effect demonstrated by its protective effect against protein and lipid oxidation

    European traditional tomatoes galore: a result of farmers’ selection of a few diversity-rich loci

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    A comprehensive collection of 1254 tomato accessions, corresponding to European traditional and modern varieties, early domesticated varieties, and wild relatives, was analyzed by genotyping by sequencing. A continuous genetic gradient between the traditional and modern varieties was observed. European traditional tomatoes displayed very low genetic diversity, with only 298 polymorphic loci (95% threshold) out of 64 943 total variants. European traditional tomatoes could be classified into several genetic groups. Two main clusters consisting of Spanish and Italian accessions showed higher genetic diversity than the remaining varieties, suggesting that these regions might be independent secondary centers of diversity with a different history. Other varieties seem to be the result of a more recent complex pattern of migrations and hybridizations among the European regions. Several polymorphic loci were associated in a genome-wide association study with fruit morphological traits in the European traditional collection. The corresponding alleles were found to contribute to the distinctive phenotypic characteristic of the genetic varietal groups. The few highly polymorphic loci associated with morphological traits in an otherwise a low-diversity population suggests a history of balancing selection, in which tomato farmers likely maintained the morphological variation by inadvertently applying a high selective pressure within different varietal types.This work was supported by the European Commission H2020 research and innovation program through TRADITOM grant agreement no. 634561, G2P-SOL, grant agreement no. 677379, and HARNESSTOM grant agreement no. 101000716. MP is grateful to the Spanish Ministerio de Ciencia e Innovación for a postdoctoral grant (IJC2019-039091-I/AEI/10.13039/501100011033).Postprint (published version

    Current knowledge, status and future for plant and fungal diversity in Great Britain and the UK Overseas Territories

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    Societal Impact Statement We rely on plants and fungi for most aspects of our lives. Yet plants and fungi are under threat, and we risk losing species before we know their identity, roles, and potential uses. Knowing names, distributions, and threats are first steps toward effective conservation action. Accessible products like field guides and online resources engage society, harnessing collective support for conservation. Here, we review current knowledge of the plants and fungi of the UK and UK Overseas Territories, highlighting gaps to help direct future research efforts toward conserving these vital elements of biodiversity. Summary This review summarizes current knowledge of the status and threats to the plants and fungi of Great Britain and the UK Overseas Territories (UKOTs). Although the body of knowledge is considerable, the distribution of information varies substantially, and we highlight knowledge gaps. The UK vascular flora is the most well studied and we have a relatively clear picture of its 9,001 native and alien taxa. We have seedbanked 72% of the native and archaeophyte angiosperm taxa and 78% of threatened taxa. Knowledge of the UKOTs flora varies across territories and we report a UKOTs flora comprising 4,093 native and alien taxa. We have conserved 27% of the native flora and 51% of the threatened vascular plants in Kew's Millennium Seed Bank, UK. We need a better understanding of the conservation status of plants in the wild, and progress toward completion or updating national red lists varies. Site‐based protection of key plant assemblages is outlined, and progress in identifying Important Plant Areas analyzed. Knowledge of the non‐vascular flora, especially seaweeds remains patchy, particularly in many UKOTs. The biggest gaps overall are in fungi, particularly non‐lichenized fungi. Considerable investment is needed to fill these knowledge gaps and instigate effective conservation strategies

    Biological Activities of Polyphenols from Grapes

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    The dietary consumption of grape and its products is associated with a lower incidence of degenerative diseases such as cardiovascular disease and certain types of cancers. Most recent interest has focused on the bioactive phenolic compounds in grape. Anthocyanins, flavanols, flavonols and resveratrol are the most important grape polyphenols because they possess many biological activities, such as antioxidant, cardioprotective, anticancer, anti-inflammation, antiaging and antimicrobial properties. This review summarizes current knowledge on the bioactivities of grape phenolics. The extraction, isolation and identification methods of polyphenols from grape as well as their bioavailability and potential toxicity also are included

    Cell-Autonomous Alterations in Dendritic Arbor Morphology and Connectivity Induced by Overexpression of MeCP2 in Xenopus Central Neurons In Vivo

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    Methyl CpG binding protein-2 (MeCP2) is an essential epigenetic regulator in human brain development. Mutations in the MeCP2 gene have been linked to Rett syndrome, a severe X-linked progressive neurodevelopmental disorder, and one of the most common causes of mental retardation in females. MeCP2 duplication and triplication have also been found to affect brain development, indicating that both loss of function and gain in MeCP2 dosage lead to similar neurological phenotypes. Here, we used the Xenopus laevis visual system as an in vivo model to examine the consequence of increased MeCP2 expression during the morphological maturation of individual central neurons in an otherwise intact brain. Single-cell overexpression of wild-type human MeCP2 was combined with time-lapse confocal microscopy imaging to study dynamic mechanisms by which MeCP2 influences tectal neuron dendritic arborization. Analysis of neurons co-expressing DsRed2 demonstrates that MeCP2 overexpression specifically interfered with dendritic elaboration, decreasing the rates of branch addition and elimination over a 48 hour observation period. Moreover, dynamic analysis of neurons co-expressing wt-hMeCP2 and PSD95-GFP revealed that even though neurons expressing wt-hMeCP2 possessed significantly fewer dendrites and simpler morphologies than control neurons at the same developmental stage, postsynaptic site density in wt-hMeCP2-expressing neurons was similar to controls and increased at a rate higher than controls. Together, our in vivo studies support an early, cell-autonomous role for MeCP2 during the morphological differentiation of neurons and indicate that perturbations in MeCP2 gene dosage result in deficits in dendritic arborization that can be compensated, at least in part, by synaptic connectivity changes
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