We apply the energy momentum and angular momentum tensor to a tetrad field, with two unknown functions of radial coordinate, in the framework of a teleparallel equivalent of general relativity （TEGR）. The definition...We apply the energy momentum and angular momentum tensor to a tetrad field, with two unknown functions of radial coordinate, in the framework of a teleparallel equivalent of general relativity （TEGR）. The definition of the gravitational energy is used to investigate the energy within the external event horizon of the dyadosphere region for the Reissner-NordstrSm black hole. We also calculate the spatial momentum and angular momentum.展开更多
Laparoscopic wedge resection is a useful procedure fortreating patients with submucosal tumor(SMT) including gastrointestinal stromal tumor(GIST) of the stomach. However, resection of intragastric-type SMTs can be pro...Laparoscopic wedge resection is a useful procedure fortreating patients with submucosal tumor(SMT) including gastrointestinal stromal tumor(GIST) of the stomach. However, resection of intragastric-type SMTs can be problematic due to the difficulty in accurately judging the location of endoluminal tumor growth, and often excessive amounts of healthy mucosa are removed; thus, full-thickness local excision using laparoscopic and endoscopic cooperative surgery(LECS) is a promising procedure for these cases. Our experience with LECS has confirmed this procedure to be a safe, feasible, and minimally invasive treatment method for gastric GISTs less than 5 cm in diameter, with outcomes similar to conventional laparoscopic wedge resection. The important advantage of LECS is the reduction in the resected area of the gastric wall compared to that in conventional laparoscopic wedge resection using a linear stapler. Early gastric cancer fits the criteria for endoscopic resection; however, if performing endoscopic submucosal dissection is difficult, the LECS procedure might be a good alternative. In the future, LECS is also likely to be indicated for duodenal tumors, as well as gastric tumors. Furthermore, developments in endoscopic and laparoscopic technology have generated various modified LECS techniques, leading to even less invasive surgery.展开更多
Nb-doped TiC ceramic,or (NbyTi1-y) Cx,in which amount of Nb element added is increased from zero to 40Wt. %, synthisized -with self-propagating high temperature synthesis,is studied with SCF-Xa-DV,a quantum chemistry ...Nb-doped TiC ceramic,or (NbyTi1-y) Cx,in which amount of Nb element added is increased from zero to 40Wt. %, synthisized -with self-propagating high temperature synthesis,is studied with SCF-Xa-DV,a quantum chemistry cal-culating method. The chemical bonding is studied to discuss the relation between structrues and properties. Several classes of models in which there is no vacancy,one vacancy or two vacan-cies have been calculated. From the calculated results of bond or-der, a measure of covalent bond strength,and molecule orbital contour map, it is concluded that when Nb element added in-creases, the vacancies increase correspondingly,the covalent com-ponent of chemical bonds of the samples decreases -while the met-al-bonding component increases, so the hardness and resistance of the samples decrease.展开更多
AIM: To investigate changes in oxidative stress in Crohn's disease(CD) before and after anti-tumor necrosis factor(TNF)-α treatment.METHODS: A total of 42 patients with active CD, who were scheduled to be treated...AIM: To investigate changes in oxidative stress in Crohn's disease(CD) before and after anti-tumor necrosis factor(TNF)-α treatment.METHODS: A total of 42 patients with active CD, who were scheduled to be treated by anti-TNF-α antibodies, were enrolled. Serum levels of diacron-reactive oxygen metabolites(d-ROM), biological antioxidant potential(BAP), and modified ratio of oxidative stress and antioxidant capacity(m-OA) were measured using the Free Radical Analytical System before and 8 wk after induction of therapy with infliximab or adalimumab. The values for oxidative stress were correlated with disease activity and clinical response as determined by the CD activity index(CDAI) at 8 and 54 wk after the therapy.RESULTS: Prior to treatment, d-ROM showed significant correlations with CDAI(r = 0.42, P < 0.01). There was a significant negative correlation between m-OA and CDAI before and after treatment(r =-0.48 vs r =-0.42, P < 0.01). CDAI and d-ROM had decreased significantly by 8 wk after treatment(CDAI; 223.3 ± 113.2 vs 158.3 ± 73.4, P < 0.01, d-ROM; 373 ± 133 vs 312 ± 101, P < 0.05). However, neither BAP nor m-OA had changed significantly. In patients who had responded to the treatment at 8 wk, d-ROM, BAP, and m-OA levels before treatment did not differ significantly between patients with and without loss of response.CONCLUSION: Anti-TNF-α therapy decreases oxi-dative stress in patients with CD, but does not alter the production of antioxidants. Dysregulation of antioxidants may be associated with the disease.展开更多
Currently there is an increase in the emergence and re-emergence of bacterial infections,and lichens are potential sources of pharmaceutically important secondary metabolites to halt this problem.Lichens are unique pl...Currently there is an increase in the emergence and re-emergence of bacterial infections,and lichens are potential sources of pharmaceutically important secondary metabolites to halt this problem.Lichens are unique plant-like organisms which are relatively less explored in the Philippines.Here,lichen extracts of Leptogium cochleatum and Leptogium moluccanum were tested against Escherichia coli,Enterobacter agglomerans,Klebsiella pneumoniae,Pseudomonas aeruginosa,and Staphylococcus aureus using paper disk diffusion assay.Hexane extract of L.moluccanum led to a 17.14 mm zone of inhibition(ZOI)against K.pneumoniae,while hexane extract of L.cochleatum led to a 15.28 mm ZOI against E.agglomerans.Dichloromethane extracts of L.cochleatum exhibited a ZOI of 15.86 mm against E.agglomerans and 14.84 mm ZOI against E.coli.The bioactivities exhibited by the lichen extracts may be due to the secondary metabolites detected using thin layer chromatography.Indeed,lichen-derived bioactive compounds hold great promise for pharmaceutical applications for the benefit of human life.展开更多
Motivated by the recent pioneering advances on nanoscale plasmonics and also nanophotonics tech- nology based on the surface plasmons （SPs）, in this work, we give a master equation model in the Lindblad form and inv...Motivated by the recent pioneering advances on nanoscale plasmonics and also nanophotonics tech- nology based on the surface plasmons （SPs）, in this work, we give a master equation model in the Lindblad form and investigate the quantum optical properties of single quantum dot （QD） emitter coupled to the SPs of a metallic nanowire. Our main results demonstrate the QD luminescence results of photon emission show three distinctive regimes depending on the distance between QD and metallic nanowire, which elucidates a crossover passing from being metallic dissipative for much smaller emitter-nanowire distances to surface plasmon （SP） emission for larger separations at the vicinity of plasmonic metallic nanowire. Besides, our results also indicate that, for both the resonant case and the detuning case, through measuring QD emitter luminescence spectra and second-order correlation functions, the information about the QD emitter coupling to the SPs of the dissipative metallic nanowire can be extracted. This theoretical study will serve as an introduction to un- derstanding the nanoplasmonic imaging spectroscopy and pave a new way to realize the quantum information devices.展开更多
Polaronic effect is important in the current researches on quantum dots (QD). This paper reported a new concept of the 'confined polaron', their size dependent formation possibilities and energy variation in d...Polaronic effect is important in the current researches on quantum dots (QD). This paper reported a new concept of the 'confined polaron', their size dependent formation possibilities and energy variation in different QD systems, with an indication of contribution from both intrinsic and/or extrinsic phonons. To understand the spectro-scopic characteristics of porous silicon (PS), we find that luminescence behavior of oxidized porous silicon is in good agreement with the model of interfacial confined polaron in QDs. This conclusion is useful to unveiling the mechanmism of PS luminescence.展开更多
【目的】煤矿井下普遍存在低照度、弱纹理和结构化的特征退化场景,导致视觉SLAM(visual simultaneous localization and mapping)系统面临有效特征不足或误匹配率高的问题,严重制约了其定位的准确性和鲁棒性。【方法】提出一种基于边缘...【目的】煤矿井下普遍存在低照度、弱纹理和结构化的特征退化场景,导致视觉SLAM(visual simultaneous localization and mapping)系统面临有效特征不足或误匹配率高的问题,严重制约了其定位的准确性和鲁棒性。【方法】提出一种基于边缘感知增强的视觉SLAM方法。首先,构建了边缘感知约束的低光图像增强模块。通过自适应尺度的梯度域引导滤波器优化Retinex算法,以获得纹理清晰光照均匀的图像,从而显著提升了在低光照和不均匀光照条件下特征提取性能。其次,在视觉里程计中构建了边缘感知增强的特征提取和匹配模块,通过点线特征融合策略有效增强了弱纹理和结构化场景中特征的可检测性和匹配准确性。具体使用边缘绘制线特征提取算法(edge drawing lines,EDLines)提取线特征,定向FAST和旋转BRIEF点特征提取算法(oriented fast and rotated brief,ORB)提取点特征,并利用基于网格运动统计(grid-based motion statistics,GMS)和比值测试匹配算法进行精确匹配。最后,将该方法与ORB-SLAM2、ORB-SLAM3在TUM数据集和煤矿井下实景数据集上进行了全面实验验证,涵盖图像增强、特征匹配和定位等多个环节。【结果和结论】结果表明:(1)在TUM数据集上的测试结果显示,所提方法与ORB-SLAM2相比,绝对轨迹误差、相对轨迹误差的均方根误差分别降低了4%~38.46%、8.62%~50%;与ORB-SLAM3相比,绝对轨迹误差、相对轨迹误差的均方根误差分别降低了0~61.68%、3.63%~47.05%。(2)在煤矿井下实景实验中,所提方法的定位轨迹更接近于相机运动参考轨迹。(3)有效提高了视觉SLAM在煤矿井下特征退化场景中的准确性和鲁棒性,为视觉SLAM技术在煤矿井下的应用提供了技术解决方案。研究面向井下特征退化场景的视觉SLAM方法,对于推动煤矿井下移动式装备机器人化具有重要意义。展开更多
Vice President Meng Liqiu of Technical University of Munich （TUM） visited Tsinghua University on July 7, 2008. Tsinghua Vice President Kang Kejun had a discussion with Professor Meng. VP Kang briefed Professor Meng ...Vice President Meng Liqiu of Technical University of Munich （TUM） visited Tsinghua University on July 7, 2008. Tsinghua Vice President Kang Kejun had a discussion with Professor Meng. VP Kang briefed Professor Meng on Tsinghua＇s recent developments in aerospace, energy, electrical engineering, life science, and management.展开更多
文摘We apply the energy momentum and angular momentum tensor to a tetrad field, with two unknown functions of radial coordinate, in the framework of a teleparallel equivalent of general relativity （TEGR）. The definition of the gravitational energy is used to investigate the energy within the external event horizon of the dyadosphere region for the Reissner-NordstrSm black hole. We also calculate the spatial momentum and angular momentum.
文摘Laparoscopic wedge resection is a useful procedure fortreating patients with submucosal tumor(SMT) including gastrointestinal stromal tumor(GIST) of the stomach. However, resection of intragastric-type SMTs can be problematic due to the difficulty in accurately judging the location of endoluminal tumor growth, and often excessive amounts of healthy mucosa are removed; thus, full-thickness local excision using laparoscopic and endoscopic cooperative surgery(LECS) is a promising procedure for these cases. Our experience with LECS has confirmed this procedure to be a safe, feasible, and minimally invasive treatment method for gastric GISTs less than 5 cm in diameter, with outcomes similar to conventional laparoscopic wedge resection. The important advantage of LECS is the reduction in the resected area of the gastric wall compared to that in conventional laparoscopic wedge resection using a linear stapler. Early gastric cancer fits the criteria for endoscopic resection; however, if performing endoscopic submucosal dissection is difficult, the LECS procedure might be a good alternative. In the future, LECS is also likely to be indicated for duodenal tumors, as well as gastric tumors. Furthermore, developments in endoscopic and laparoscopic technology have generated various modified LECS techniques, leading to even less invasive surgery.
文摘Nb-doped TiC ceramic,or (NbyTi1-y) Cx,in which amount of Nb element added is increased from zero to 40Wt. %, synthisized -with self-propagating high temperature synthesis,is studied with SCF-Xa-DV,a quantum chemistry cal-culating method. The chemical bonding is studied to discuss the relation between structrues and properties. Several classes of models in which there is no vacancy,one vacancy or two vacan-cies have been calculated. From the calculated results of bond or-der, a measure of covalent bond strength,and molecule orbital contour map, it is concluded that when Nb element added in-creases, the vacancies increase correspondingly,the covalent com-ponent of chemical bonds of the samples decreases -while the met-al-bonding component increases, so the hardness and resistance of the samples decrease.
文摘AIM: To investigate changes in oxidative stress in Crohn's disease(CD) before and after anti-tumor necrosis factor(TNF)-α treatment.METHODS: A total of 42 patients with active CD, who were scheduled to be treated by anti-TNF-α antibodies, were enrolled. Serum levels of diacron-reactive oxygen metabolites(d-ROM), biological antioxidant potential(BAP), and modified ratio of oxidative stress and antioxidant capacity(m-OA) were measured using the Free Radical Analytical System before and 8 wk after induction of therapy with infliximab or adalimumab. The values for oxidative stress were correlated with disease activity and clinical response as determined by the CD activity index(CDAI) at 8 and 54 wk after the therapy.RESULTS: Prior to treatment, d-ROM showed significant correlations with CDAI(r = 0.42, P < 0.01). There was a significant negative correlation between m-OA and CDAI before and after treatment(r =-0.48 vs r =-0.42, P < 0.01). CDAI and d-ROM had decreased significantly by 8 wk after treatment(CDAI; 223.3 ± 113.2 vs 158.3 ± 73.4, P < 0.01, d-ROM; 373 ± 133 vs 312 ± 101, P < 0.05). However, neither BAP nor m-OA had changed significantly. In patients who had responded to the treatment at 8 wk, d-ROM, BAP, and m-OA levels before treatment did not differ significantly between patients with and without loss of response.CONCLUSION: Anti-TNF-α therapy decreases oxi-dative stress in patients with CD, but does not alter the production of antioxidants. Dysregulation of antioxidants may be associated with the disease.
文摘Currently there is an increase in the emergence and re-emergence of bacterial infections,and lichens are potential sources of pharmaceutically important secondary metabolites to halt this problem.Lichens are unique plant-like organisms which are relatively less explored in the Philippines.Here,lichen extracts of Leptogium cochleatum and Leptogium moluccanum were tested against Escherichia coli,Enterobacter agglomerans,Klebsiella pneumoniae,Pseudomonas aeruginosa,and Staphylococcus aureus using paper disk diffusion assay.Hexane extract of L.moluccanum led to a 17.14 mm zone of inhibition(ZOI)against K.pneumoniae,while hexane extract of L.cochleatum led to a 15.28 mm ZOI against E.agglomerans.Dichloromethane extracts of L.cochleatum exhibited a ZOI of 15.86 mm against E.agglomerans and 14.84 mm ZOI against E.coli.The bioactivities exhibited by the lichen extracts may be due to the secondary metabolites detected using thin layer chromatography.Indeed,lichen-derived bioactive compounds hold great promise for pharmaceutical applications for the benefit of human life.
基金This work was financially supported by the National Natural Science Foundation of China under Grant No. 60721004, and the National Basic Research Program of China under Grant No. 2009CB010600.
文摘Motivated by the recent pioneering advances on nanoscale plasmonics and also nanophotonics tech- nology based on the surface plasmons （SPs）, in this work, we give a master equation model in the Lindblad form and investigate the quantum optical properties of single quantum dot （QD） emitter coupled to the SPs of a metallic nanowire. Our main results demonstrate the QD luminescence results of photon emission show three distinctive regimes depending on the distance between QD and metallic nanowire, which elucidates a crossover passing from being metallic dissipative for much smaller emitter-nanowire distances to surface plasmon （SP） emission for larger separations at the vicinity of plasmonic metallic nanowire. Besides, our results also indicate that, for both the resonant case and the detuning case, through measuring QD emitter luminescence spectra and second-order correlation functions, the information about the QD emitter coupling to the SPs of the dissipative metallic nanowire can be extracted. This theoretical study will serve as an introduction to un- derstanding the nanoplasmonic imaging spectroscopy and pave a new way to realize the quantum information devices.
文摘Polaronic effect is important in the current researches on quantum dots (QD). This paper reported a new concept of the 'confined polaron', their size dependent formation possibilities and energy variation in different QD systems, with an indication of contribution from both intrinsic and/or extrinsic phonons. To understand the spectro-scopic characteristics of porous silicon (PS), we find that luminescence behavior of oxidized porous silicon is in good agreement with the model of interfacial confined polaron in QDs. This conclusion is useful to unveiling the mechanmism of PS luminescence.
文摘【目的】煤矿井下普遍存在低照度、弱纹理和结构化的特征退化场景,导致视觉SLAM(visual simultaneous localization and mapping)系统面临有效特征不足或误匹配率高的问题,严重制约了其定位的准确性和鲁棒性。【方法】提出一种基于边缘感知增强的视觉SLAM方法。首先,构建了边缘感知约束的低光图像增强模块。通过自适应尺度的梯度域引导滤波器优化Retinex算法,以获得纹理清晰光照均匀的图像,从而显著提升了在低光照和不均匀光照条件下特征提取性能。其次,在视觉里程计中构建了边缘感知增强的特征提取和匹配模块,通过点线特征融合策略有效增强了弱纹理和结构化场景中特征的可检测性和匹配准确性。具体使用边缘绘制线特征提取算法(edge drawing lines,EDLines)提取线特征,定向FAST和旋转BRIEF点特征提取算法(oriented fast and rotated brief,ORB)提取点特征,并利用基于网格运动统计(grid-based motion statistics,GMS)和比值测试匹配算法进行精确匹配。最后,将该方法与ORB-SLAM2、ORB-SLAM3在TUM数据集和煤矿井下实景数据集上进行了全面实验验证,涵盖图像增强、特征匹配和定位等多个环节。【结果和结论】结果表明:(1)在TUM数据集上的测试结果显示,所提方法与ORB-SLAM2相比,绝对轨迹误差、相对轨迹误差的均方根误差分别降低了4%~38.46%、8.62%~50%;与ORB-SLAM3相比,绝对轨迹误差、相对轨迹误差的均方根误差分别降低了0~61.68%、3.63%~47.05%。(2)在煤矿井下实景实验中,所提方法的定位轨迹更接近于相机运动参考轨迹。(3)有效提高了视觉SLAM在煤矿井下特征退化场景中的准确性和鲁棒性,为视觉SLAM技术在煤矿井下的应用提供了技术解决方案。研究面向井下特征退化场景的视觉SLAM方法,对于推动煤矿井下移动式装备机器人化具有重要意义。
文摘Vice President Meng Liqiu of Technical University of Munich （TUM） visited Tsinghua University on July 7, 2008. Tsinghua Vice President Kang Kejun had a discussion with Professor Meng. VP Kang briefed Professor Meng on Tsinghua＇s recent developments in aerospace, energy, electrical engineering, life science, and management.
