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MicroRNAs (miRNAs) are involved in several biological processes including development, differentiation and proliferation. Analysis of miRNA expression patterns in the process of embryogenesis may have substantial value in determining the mechanism of embryonic bladder development as well as for eventual therapeutic intervention. The miRNA expression profiles are distinct among the cellular types and embryonic stages as demonstrated by microarray technology and validated by quantitative real-time RT-PCR approach. Remarkably, the miRNA expression patterns suggested that unique miRNAs from epithelial and submucosal areas are responsible for mesenchymal cellular differentiation, especially regarding bladder smooth muscle cells. Our data show that miRNA expression patterns are unique in particular cell types of mouse bladder at specific developmental stages, reflecting the apparent lineage and differentiation status within the embryonic bladder. The identification of unique miRNAs expression before and after smooth muscle differentiation in site-specific area of the bladder indicates their roles in embryogenesis and may aid in future clinical intervention.  相似文献   
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Sustainable use of wood may contribute to coping with energy and material resource challenges. The goal of this study is to increase knowledge of the environmental effects of wood use by analyzing the complete value chain of all wooden goods produced or consumed in Switzerland. We start from a material flow analysis of current wood use in Switzerland. Environmental impacts related to the material flows are evaluated using life cycle assessment–based environmental indicators. Regarding climate change, we find an overall average benefit of 0.5 tonnes carbon dioxide equivalent per cubic meter of wood used. High environmental benefits are often achieved when replacing conventional heat production and energy‐consuming materials in construction and furniture. The environmental performance of wood is, however, highly dependent on its use and environmental indicators. To exploit the mitigation potential of wood, we recommend to (1) apply its use where there are high substitution benefits like the replacement of fossil fuels for energy or energy‐intensive building materials, (2) take appropriate measures to minimize negative effects like particulate matter emissions, and (3) keep a systems perspective to weigh effects like substitution and cascading against each other in a comprehensive manner. The results can provide guidance for further in‐depth studies and prospective analyses of wood‐use scenarios.  相似文献   
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生命周期管理研究述评   总被引:5,自引:2,他引:3  
黄和平 《生态学报》2017,37(13):4587-4598
生命周期管理起源于生命周期思想,它是生命周期思想在实践中的具体应用,是面向可持续生产和消费,对产品、工艺和服务的全生命周期环境影响进行的综合管理,是解决复合生态系统中结构无序、效率不高和代谢冗余的有效途径,是基于生命周期评价原则与框架的一种环境管理手段或环境管理体系。全面回顾了生命周期管理的起源与内涵,阐述了生命周期管理与生命周期评价的区别与联系,梳理了生命周期管理与环境管理体系的关系。对生命周期管理在产品、企业、行业及城市等层次上的具体应用进行了总结与述评,并对其今后需深入研究的方向进行了展望。  相似文献   
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Melatonin, a neuroendocrine hormone synthesized by the pineal gland and cholangiocytes, decreases biliary hyperplasia and liver fibrosis during cholestasis-induced biliary injury via melatonin-dependent autocrine signaling through increased biliary arylalkylamine N-acetyltransferase (AANAT) expression and melatonin secretion, downregulation of miR-200b and specific circadian clock genes. Melatonin synthesis is decreased by pinealectomy (PINX) or chronic exposure to light. We evaluated the effect of PINX or prolonged light exposure on melatonin-dependent modulation of biliary damage/ductular reaction/liver fibrosis. Studies were performed in male rats with/without BDL for 1 week with 12:12 h dark/light cycles, continuous light or after 1 week of PINX. The expression of AANAT and melatonin levels in serum and cholangiocyte supernatant were increased in BDL rats, while decreased in BDL rats following PINX or continuous light exposure. BDL-induced increase in serum chemistry, ductular reaction, liver fibrosis, inflammation, angiogenesis and ROS generation were significantly enhanced by PINX or light exposure. Concomitant with enhanced liver fibrosis, we observed increased biliary senescence and enhanced clock genes and miR-200b expression in total liver and cholangiocytes. In vitro, the expression of AANAT, clock genes and miR-200b was increased in PSC human cholangiocyte cell lines (hPSCL). The proliferation and activation of HHStecs (human hepatic stellate cell lines) were increased after stimulating with BDL cholangiocyte supernatant and further enhanced when stimulated with BDL rats following PINX or continuous light exposure cholangiocyte supernatant via intracellular ROS generation. Conclusion: Melatonin plays an important role in the protection of liver against cholestasis-induced damage and ductular reaction.  相似文献   
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Goal and Background  Current Life Cycle Impact Assessment (LCIA) procedures have demonstrated certain limitations in the South African manufacturing industry context. The aim of this paper is to propose a modified LCIA procedure, which is based on the protection of resource groups. Methods  A LCIA framework is introduced that applies the characterisation procedure of available midpoint categories, with the exception of land use. Characterisation factors for land occupation and transformation is suggested for South Africa. A distanceto-target approach is used for the normalisation of midpoint categories, which focuses on the ambient quality and quantity objectives for four resource groups: Air, Water, Land and Mined Abiotic Resources. The quality and quantity objectives are determined for defined South African Life Cycle Assessment (SALCA) Regions and take into account endpoint or damage targets. Following the precautionary approach, a Resource Impact Indicator (RII) is calculated for the resource groups. Subjective weighting values for the resource groups are also proposed, based on survey results from the manufacturing industry sector and the expenditure trends of the South African national government. The subjective weighting values are used to calculate overall Environmental Performance Resource Impact Indicators (EPRIIs) when comparing life cycle systems with each other. The proposed approaches are evaluated with a known wool case study. Results and Discussion  The calculation of a RJI ensures that all natural resources that are important from a South African perspective are duly considered in a LCIA. The results of a LCIA are consequently not reliant on a detailed Life Cycle Inventory (LCI) and the number of midpoint categories that converge on a single resource group. The case study establishes the importance of region-specificity, for LCIs and LCIAs. Conclusions  The proposed LCIA procedure demonstrates reasonable ease of communication of LCIA results. It further allows for the inclusion of additional midpoint categories and is adaptable for specific regions. Recommendations and Outlook  The acceptance of the LCIA procedure must be evaluated for different industry and government sectors. Also, the adequate incorporation of Environmental Performance Resource Impact Indicators (EPRIIs) into decision-making for Life Cycle Management purposes must be researched further. Specifically, the application of the procedures for supply chain management will be investigated.  相似文献   
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We analyzed RNA gene expression in neurons from 16 cases in four categories, HIV associated dementia with HIV encephalitis (HAD/HIVE), HAD alone, HIVE alone, and HIV-1-positive (HIV+)with neither HAD nor HIVE. We produced the neurons by laser capture microdissection (LCM) from cryopreserved globus pallidus. Of 55,000 gene fragments analyzed, expression of 197 genes was identified with significance (p = 0.005).We examined each gene for its position in the human genome and found a non-stochastic occurrence for only seven genes, on chromosome 22. Six of the seven genes were identified, CSNK1E (casein kinase 1 epsilon), DGCR8 (Di George syndrome critical region 8), GGA1 (Golgi associated gamma adaptin ear containing ARF binding protein 1), MAPK11 (mitogen activated protein kinase 11), SMCR7L (Smith-Magenis syndrome chromosome region candidate 7-like), andTBC1D22A (TBC1 domain family member 22A). Six genes (CSNK1E, DGCR8, GGA1, MAPK11, SMCR7L, and one unidentified gene) had similar expression profiles across HAD/HIVE, HAD, and HIVE vs. HIV+ whereas one gene (TBC1D22A) had a differing gene expression profile across these patient categories. There are several mental disease-related genes including miRNAs on chromosome 22 and two of the genes (DGCR8 and SMCR7L) identified here are mental disease-related. We speculate that dysregulation of gene expression may occur through mechanisms involving chromatin damage and remodeling. We conclude that the pathogenesis of NeuroAIDS involves dysregulation of expression of mental disease-related genes on chromosome 22 as well as additional genes on other chromosomes. The involvement of these genes as well as miRNA requires additional investigation since numerous genes appear to be involved.  相似文献   
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目的:比较纳米瓷充填材料和复合树脂充填乳牙V类洞边缘微渗漏的影响以及固化效率的差异。方法:第一部分为微渗漏实验,选取滞留拔除的上颌乳前牙20颗,唇侧制备V类洞,随机分为A、B两组,分别用Composan LCM和Filtek~(TM) Z350充填,亚甲基蓝染色处理,24 h后使用体式显微镜观察,测量染料渗入深度为微渗漏值,每组各选2个样本扫描电镜观察充填体与牙体组织间粘结情况。第二部分为显微硬度实验,分别用两种充填材料制作模块各9个,记为A、B两组,材料模块光固化24 h后使用显微硬度仪检测充填材料的固化效率。结果:Composan LCM组微渗漏值明显低于Filtek~(TM)Z350组(P0.05);扫描电镜下观察Filtek~(TM) Z350组充填材料与牙体组织间可见裂缝,界面参差不齐,有不连续的小断裂,Composan LCM组界面连续均匀,未见明显裂缝;两组充填材料的固化效率无显著差异(P0.05)。结论:纳米瓷充填材料和复合树脂均可用于乳牙龋洞充填,使用纳米瓷充填材料可减少微渗漏。  相似文献   
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