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991.
Vacuum ultraviolet(VUV)lasers have demonstrated great potential as the light source for various spectroscopies,which,if they can be focused into a small beam spot,will not only allow investigation of mesoscopic materials and structures but also find application in the manufacture of nano-objects with excellent precision.In this work,we report the construction of a 177 nm VUV laser that can achieve a record-small(〜0.76 μm)focal spot at a long focal length(~45 mm)by using a flat lens without spherical aberration.The size of the beam spot of this VUV laser was tested using a metal grating and exfoliated graphene flakes,and we demonstrated its application in a fluorescence spectroscopy study on pure and Tm3+-doped NaYF4 microcrystals,revealing a new emission band that cannot be observed in the traditional up-conversion process.In addition,this laser system would be an ideal light source for spatially and angleresolved photoemission spectroscopy.  相似文献   
992.
To investigate highway petrol station replenishment in initiative distribution mode,this paper develops a mixed-integer linear programming(MILP)model with minim...  相似文献   
993.
A growing body of research suggests that inflammatory insult contributes to the etiology of central nervous system diseases, such as depression, Alzheimer’s disease, and so forth. However, the effect of prenatal systemic inflammation exposure on offspring brain development and cerebral susceptibility to inflammatory insult remains unknown. In this study, we utilized the prenatal inflammatory insult model in vivo and the neuronal damage model in vitro. The results obtained show that prenatal maternal inflammation exacerbates LPS-induced memory impairment, neuronal necrosis, brain inflammatory response, and significantly increases protein expressions of COX-2, DP2, APP, and Aβ, while obviously decreasing that of DP1 and the exploratory behaviors of offspring rats. Meloxicam significantly inhibited memory impairment, neuronal necrosis, oxidative stress, and inflammatory response, and down-regulated the expressions of APP, Aβ, COX-2, and DP2, whereas significantly increased exploring behaviors and the expression of DP1 in vivo. Collectively, these findings suggested that maternal inflammation could cause offspring suffering from inflammatory and behavioral disorders and increase the susceptibility of offspring to cerebral pathological factors, accompanied by COX-2/PGD-2/DPs pathway activation, which could be ameliorated significantly by COX-2 inhibitor meloxicam treatment.  相似文献   
994.
Efficient electron transport layers(ETLs)not only play a crucial role in promoting carrier separation and electron extraction in perovskite solar cells(PSCs)but...  相似文献   
995.
兰州石化分公司新建30万t/a聚丙烯装置概况及特点   总被引:2,自引:1,他引:1  
介绍了中国石油兰州石化分公司采用Basell公司Spheripol-Ⅱ技术新建30万t/a聚丙烯装置的工艺特点和产品方案.  相似文献   
996.
Temperature-sensitive genic male sterile (TGMS) line Beijing Sterility 366 (BS366) has been utilized in hybrid breeding for a long time, but the molecular mechanism underlying male sterility remains unclear. Expression arrays, small RNA, and degradome sequencing were used in this study to explore the potential role of miRNA in the cold-induced male sterility of BS366. Microspore observation showed defective cell plates in dyads and tetrads and shrunken microspores at the vacuolated stage. Differential regulation of Golgi vesicle transport, phragmoplast formation, sporopollenin biosynthesis, pollen exine formation, and lipid metabolism were observed between cold and control conditions. Pollen development was significantly represented in the 352 antagonistic miRNA-target pairs in the integrated analysis of miRNA and mRNA profiles. The specific cleavage of ARF17 and TIR1 by miR160 and miR393 were found in the cold-treated BS366 degradome, respectively. Thus, the cold-mediated miRNAs impaired cell plate formation through repression of Golgi vesicle transport and phragmoplast formation. The repressed expression of ARF17 and TIR1 impaired pollen exine formation. The results of this study will contribute to our understanding of the roles of miRNAs in male sterility in wheat.  相似文献   
997.
Anthocyanins accumulate in various organs of rice, and the regulatory genes involved in pigmentation of specific organs, such as pericarp, hull, leaf, apiculus, and stigma have been elucidated. However, the corresponding gene for rice culm pigmentation has not been clarified. The well-known MYB-bHLH-WD40 (MBW) complex plays vital role in regulating the anthocyanin biosynthesis pathway in plants. However, the core members of MBW and the hierarchical regulation between these members are not fully elucidated in rice. Here, by map-based cloning, we identified the culm-specific pigmentation gene S1 whose alleles are also known for hull/pericarp pigmentation. We also clarified that one WD40 protein encoding gene, WA1, is indispensable for anthocyanin biosynthesis in rice. In the cascading regulation among MBW members, S1 (bHLH) acts as the master gene by activating the expression of C1 (MYB), and then C1 activates the expression of WA1 (WD40), which is unique in plant species. This enables MBW members to be coordinated in a common way to efficiently regulate anthocyanin biosynthesis genes. Based on these studies, we explored the minimal gene set required for anthocyanin biosynthesis in rice. These findings will help us design new rice varieties with anthocyanin accumulation in specific organs as needed.  相似文献   
998.
城市空间扩张及结构演化的制度因素分析   总被引:2,自引:0,他引:2  
张京祥  洪世键 《规划师》2008,24(12):40-43
改革开放以来,中国城市的发展环境发生了巨大的变迁,制度力成为深刻影响城市空间扩张与结构演变的关键因素。在转型期,中国只有加快推进地方政府企业化治理体系,土地制度、土地规制等相应的制度性变革,才是实现城市空间的集约增长、理性增长和结构优化的根本之策。  相似文献   
999.
张树江 《钢结构》2008,23(3):38-40
阐述了钢筋接驳器与柱翼缘板的可焊性、焊脚尺寸的确定和焊接过程应注意的问题,并做了详细介绍。  相似文献   
1000.
The insulin receptor (IR) is a transmembrane protein that is activated by ligands in insulin signaling pathways. The IR has been considered as a novel therapeutic target for clinical intervention, considering the overexpression of its protein and A-isoform in multiple cancers, Alzheimer’s disease, and Type 2 diabetes mellitus in humans. Meanwhile, it may also serve as a potential target in pest management due to its multiple physiological influences in insects. In this review, we provide an overview of the structural and molecular biology of the IR, functions of IRs in humans and insects, physiological and nonpeptide small molecule modulators of the IR, and the regulating mechanisms of the IR. Xenobiotic compounds and the corresponding insecticidal chemicals functioning on the IR are also discussed. This review is expected to provide useful information for a better understanding of human IR-related diseases, as well as to facilitate the development of novel small-molecule activators and inhibitors of the IR for use as medicines or pesticides.  相似文献   
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