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University of Science and Technology Beijing
Dalian University of Technology
Agricultural University of Hebei
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摘要:The luminescence lifetime of the 0.01 mol.%-0.1 mol.% Er3+- and 0-20 mol.% Y3+-codoped Al2O3 powders prepared at a sintering temperature of 900℃ in a non-aqueous sol-gel method has been investigated to explore the enhanced mechanism of photoluminescence properties of the Er3+-doped Al2O3 by Y3+ codoping. For the 0.1 mol.% Er3+ Y3+-codoped Al2O3 powders, the measured lifetime of Er3+ gradually increases with increasing Y3+ concentration. Consequently, codoping with 20 mol.% Y3+ leads to an increase in the measured lifetime from 3.5 to 5.8 ms. By comparing the measured lifetime for different Er3+ concentrations in the Al2O3 powders, the radiative lifetime of both the Er3+-doped and the Er3+-Y3+-codoped Al2O3 powders is estimated to be about 7.5 ms. Infrared absorption spectra indicate that Y3+ codoping does not change the -OH content in the Er3+-Y3+-codoped Al2O3 powders. The prolonged luminescence lifetime of the 4Ⅰ13/2 level of Er3+ in Er3+-doped Al2O3 pow-ders by Y3+ codoping is ascribed to the decrease in the energy transfer rate between the Er3+ ions and the Er3+ and -OH, respectively, due to the suppressed interaction between Er3+ ions....
[期刊论文] 王慧 黄礼年
摘要:肺癌是全球癌症相关死亡的主要原因,肺癌的治愈率很低,不仅因其自身攻击性,还因对肺癌筛查的忽视。随着肺部筛查手段的不断进展,肺外周病变的检出率逐渐提高,当前对外周肺病变进行诊断的最常用方法是经支气管行支气管镜检查或计算机断层扫描(computed tomography, CT)引导下经皮穿刺针吸/活检,然而对于外周肺病灶,支气管镜检查有较低的诊断率,经皮穿刺检查有较高的气胸发生率,因此,使用安全、微创的方法对外周肺病变进行组织确诊是临床工作者将面临的挑战。新型支气管镜介入诊断技术已逐渐用于临床,这些技术可有效提高外周肺病变的诊断率,缩短诊断时间,使患者获得及时有效的治疗。本文将现有的技术进行简要综述以帮助临床医生尝试应用这些微创技术。...
摘要:Time-resolved Fourier transform infrared emission spectroscopy is employed for studing gaseous reaction of CH3 with NO. The CH3 radical was produced by laser photolysis of CH3Br at 248 nm. The infrared emissions of vibrationally excited nascent products HCO (v3), HCN (v1, v3), NH2 (v3), secondary product HNO (v1) and possible product HNCO (v1) were observed. It verifies that the reaction channels of HCO + NH2 and HCN+H2O exist, and that one other channel HNCO + H may also occur....
摘要:Neurodegenerative diseases are characterized by the accumulation of intracellular or extracellular protein aggregates that result from conformational changes in proteins. These diseases may result from an imbalance between the production of misfolded proteins and normal chaperone capacity. Molecular chaperones provide a first line of defence against misfolded, aggregation-prone proteins and are, therefore, promising therapeutic targets for neurodegenerative diseases....
摘要:A terylene membrane which kept pH>12 in cathode compartment was used to construct a divided cell with a carbon/polytetrafluoroethylene (C/PTFE) O2-fed cathode. The concentrations μmol/L, respectively, which were determined by permanganate titration, electron spin resonance (ESR) spectrum and the fluorescence spectra. The efficiency of the removal of phenol achieved 100% as a result of these two kinds of stronger oxidizer....
摘要:This study investigates classification and diurnal variations of the precipitation echoes over the central Tibetan Plateau based on the observations collected from a C-band vertically-pointing frequency-modulated continuous-wave (C-FMCW) radar during the Third Tibetan Plateau Atmospheric Scientific Experiment (TIPEX-III) 2014-Intensive Observation Period (2014-IOP). The results show that 51.32% of the vertical profiles have valid echoes with re-flectivity > –10 dBZ, and 35.06% of the valid echo profiles produce precipitation at the ground (precipitation pro-files); stratiform precipitation with an evident bright-band signature, weak convective precipitation, and strong con-vective precipitation account for 52.03%, 42.98%, and 4.99% of the precipitation profiles, respectively. About 59.84% of the precipitation occurs in the afternoon to midnight, while 40.16% of the precipitation with weaker in-tensity is observed in the nocturnal hours and in the morning. Diurnal variation of occurrence frequency of precipita-tion shows a major peak during 2100–2200 LST (local solar time) with 59.02% being the stratiform precipitation; the secondary peak appears during 1300–1400 LST with 59.71% being the weak convective precipitation; the strong con-vective precipitation occurs mostly (81.83%) in the afternoon and evening with two peaks over 1200–1300 and 1700–1800 LST, respectively. Starting from approximately 1100 LST, precipitation echoes develop with enhanced vertical air motion, elevated echo top, and increasing radar reflectivity. Intense upward air motion occurs most fre-quently in 1700–1800 LST with a secondary peak in 1100–1400 LST, while the tops of precipitation echoes and in-tense upward air motion reach their highest levels during 1600–1800 LST. The atmospheric conditions in the early morning are disadvantageous for convective initiation and development. Around noon, the convective available po-tential energy (CAPE) increases markedly, convective inhibition (CIN) is generally small, and a super-dry-adiabatic layer is present near the surface (0–400 m). In the early evening, some larger values of CAPE, level of neutral buoy-ancy, and total precipitable water are present, suggesting more favorable thermodynamic and water vapor conditions....
摘要:A coupled system of sea-air oscillator model is studied. Using the perturbed theory, the approximations of the solution for the sea-air oscillator model are obtained....
[期刊论文] 林涛 宋纯 王辉
摘要:目的:探讨晚期结直肠癌术中腹腔局部注射铜绿假单胞菌注射液的长期疗效。方法:收集自2006年9月至2008年3月间晚期结直肠癌患者共83例入组,其中包括治疗组30例(姑息性手术切除加术中局部注射铜绿假单胞菌注射液10 mL),对照组53例(仅姑息切除肿瘤),治疗组和对照组术后继续应用化疗和/或放疗。结果:79例患者最终完成随访,随访率达95.2%。两组之间5年总生存时间无差异性(P=0.403),但是对照组5年的中位生存期仅为(13.9±2.14)个月,而治疗组为(17.2±2.12)个月。结论:晚期结直肠癌术中腹腔局部注射铜绿假单胞菌注射液,可能在短期内具有一定的生存优势,但是长期疗效还有待考证。...
摘要:For vehicle adaptive cruise control (ACC) systems,the switching performance between throttle and brake determines the driving comfort,fuel consumption and service lives of vehicle mechanical components.In this paper,an ACC algorithm with the optimal switching control between throttle and brake is designed in model predictive control (MPC) framework.By introducing the binary integer variables,the dynamics of throttle and brake are integrated in one model expression for the controller design.Then the ACC algorithm is designed to satisfy not only safe car following,but also the optimal switching between throttle and brake,which leads to an online mixed integer quadratic programming solved by the nested two-loop method.The simulation results show that the proposed ACC algorithm meets the requirements of safe car following,outperforms the traditional algorithms by performing smoother responses,reducing the switching times between throttle and brake,and therefore improves driving comfort and fuel efficiency significantly....
摘要:Summary: The aim of this study was to investigate the effect and possible mechanism of all-trans retinoic acid (ATRA) on liver fibrosis induced by common bile duct ligation (CBDL) in rats. Fifty-three female Wistar rats were randomly divided into 5 groups: sham operation group (group J, 5 animals) and groups A, B, C and D (12 animals in each group). The rats in groups A, B, C and D were subjected to CBDL to induce liver fibrosis, while those in group J to sham operation. From the 3rd week the rats in groups B, C and D respectively received daily administration of ATRA via gastric tube at three different doses [0.1, 1.5 and 7.5 mg/kg body weight (BW)]. Animals were sacrificed at 6th week. Rats' liver tissues were observed for pathologic changes under a light microscope. The protein levels of type Ⅰ collagen (COL Ⅰ), matrix metalloproteinase-2 (MMP2), MMP13 and tissue inhibitors of metalloproteinase-1 (TIMP-1) in liver tissues were determined by immunohistochemical techniques. The expression levels of TGF-β1 and CTGF mRNA in liver tissues were detected by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The results showed that loss of normal hepatic architecture and formation of obvious fibrosis were observed in group A, while ATRA treatment for 4 weeks notably alleviated the pathological changes of hepatocytes. The expression of COL Ⅰ and TIMP-1 proteins in group A was increased, while decreased in ATRA-treated CBDL groups (P<0.05). ATRA (1.5 and 7.5 mg/kg BW) reduced the expression levels of COL Ⅰprotein more greatly than that of 0.1 mg/kg BW (P<0.05). ATRA treatment increased the protein levels of MMP2 and MMP13. The expression levels of TGF-β1 and CTGF mRNA in group A were increased. In comparison with group A, the mRNA levels of TGF-β1 and CTGF in ATRA-treated CBDL groups were significantly decreased (P<0.05). It was concluded that ATRA could inhibit CBDL-induced liver fibrosis in rats by suppressing the expression of TGF-β1 and CTGF so as to diminish the inhibition of TIMP-1 on MMP2 and MMP13 and increase the activity of MMP2 and MMP13....
摘要:Aim: To investigate the alterations of placental P-glycoprotein (P-gp) and cytochrome P450 1A1 (CYP1A1) at different gestational days (GD), and to explore the possible significance of placental P-gp and CYP1A1 in tobacco smoke-induced intrauterine growth retardation (IUGR) in rats. Methods: An IUGR model was produced by passive tobacco smoking from GD 7 to parturition (GD 21) and predicted using fetal development parameters. Placental structure and function were monitored by observing pathological alteration and antioxidative function, including the content of malondialdehyde and the activities of superoxide dismutase and catalase (CAT). The expressions of CYP1A1 and P-gp (mdr 1a and mdr 1b)were detected using a reverse transcription polymerase chain reaction and immunohistochemistry. Results: Placental pathological changes occurred and the malondialdehyde content increased, whereas the activities ofsuperoxide dismutase and CAT lowered, when compared to their controls. In the rat placenta of the tobacco group, the level of CYP1A1 mRNA increased significantly; the level of mdr1a mRNA increased significantly at GD 21 but not at GD 14, whereas the level of mdr1b mRNA in different term remained stable; the expression of P-gp increased significantly only in full-term placenta. Conclusion: The expression of placental CYP1A1 and P-gp increased in tobacco-induced IUGR. Overexpression of placental CYP1A1 can attribute to the metabolism of tobacco and the generation of reactive metabolites, which can trigger IUGR. As a compulsory mechanism,upregulation of P-gp might decrease tobacco exposure to a developing fetus with IUGR....
摘要:Symmetry of the world trade network provides a novel perspective to understand the world-wide trading system. However, symmetry in the world trade network (WTN) has been rarely studied so far. In this paper, the authors systematically explore the symmetry in WTN. The authors construct WTN in 2005 and explore the size and structure of its automorphism group, through which the authors find that WTN is symmetric, particularly, locally symmetric to a certain degree. Furthermore, the authors work out the symmetric motifs of WTN and investigate the structure and function of the symmetric motifs, coming to the conclusion that local symmetry will have great effect on the stability of the WTN and that continuous symmetry-breakings will generate complexity and diversity of the trade network. Finally, utilizing the local symmetry of the network, the authors work out the quotient of WTN, which is the structural skeleton dominating stability and evolution of WTN....
摘要:We extracted six Hong Kong brown seaweed species with hot water for their antiviral properties. The cytotoxicity and antiviral activity of these extracts were tested by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenlytetrezolium bromide] method, cytopathic effect reduction assay, and plaque reduction assay. The antiviral effect was further determined by flow cytometric analysis. The results showed that most of these extracts inhibited the propagation of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) standard strains with very low cytotoxicity to the host cells. The extracts ofHydroclathrus clathratus and Lobophora variegata showed more potential anti-HSV activities than the extracts of the other four seaweeds. They also had moderate anti-respiratory syncytial virus (RSV) activities but could not inhibit influenza A virus. Hydroclathrus clathratus was further extracted by diluted acid and alkali and the antiviral effects of the extracts were also detected. The result showed that the hot water extract contained the main carbohydrate components that exhibited the antiviral activities against various strains of HSV, including the acyclovir-resistant strain. HI-3, a compound fractionated from this hot water extract, showed a dose-dependent anti-HSV activity in flow cytometric analysis and plaque reduction assay....
摘要:In order to develop a model for screening the agonists of human 132-adrenoceptor from Chinese medicinal herbs extracts, we used a cell-based functional assay based on a common G protein-coupled receptor (GPCR) regulation mechanism and destabilized enhanced green fluorescent protein (d2EGFP) reporter gene technique. The positive cell clone was confirmed by real-time polymerase chain reaction (PCR) and imaging analysis. To assess the value of this model, we screened over 2000 high performance liquid chromatography (HPLC)-fractionated samples from the ethanol extracts of Chinese medicinal herbs. Six fractions (isolated from Panax japonicus, Veratrum nigrum, Phellodendron amurense, Fructus Aurantii Imrnaturus, Chaenomeles speciosa, and Dictamnus dasycarpus) showed significant effects on active reporter gene expression, three of which (isolated from Phellodendron amurense, Fructus Aurantii lmmaturus, and Chaenomeles speciosa) were selected for further concentration re-sponse analysis and the half maximal effective concentration (ECI/2 max) values were 4.2, 2.7, and 4.8 μg/ml, respectively.Therefore, this reporter gene assay was suitable for screening β2-adrenoceptor agonists. The results suggest that the six herbal extracts are the possible agonists of β2-adrenoceptor....
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