Under parabolic flight conditions microgravity is not lower than 3 to 5 times 10-2 g. In contrast to parabolic flights, sounding rocket flights are virtually vibrational-free allowing microgravity as low as 10-5 g. Th...Under parabolic flight conditions microgravity is not lower than 3 to 5 times 10-2 g. In contrast to parabolic flights, sounding rocket flights are virtually vibrational-free allowing microgravity as low as 10-5 g. Thus, a rotating platform serving as centrifuge allows the precise generation of gravitational forces ranging from 5 to 100 mg (not possible during parabolic flights). On this basis we determined the threshold1 for optical reflection/absorption changes in Phycomyces to be lower than 25 × 10-3 g. This compares well with the threshold determination of gravitropism in Phycomyces on a clinostat centrifuge. Kinetics of gravity-induced absorption changes and gravity as generated by the on-board centrifuge do not coincide but show a distinctive hysteresis with a latency of 4 s (75 mg-ramp, pull-up).展开更多
In the first paper of two referring to the TEXUS 50 campaign using micro dual wavelength spectrometers (MDWS) we kinetically determined the threshold1 for GIACs (gravity-induced absorption changes) in Phycomyces to be...In the first paper of two referring to the TEXUS 50 campaign using micro dual wavelength spectrometers (MDWS) we kinetically determined the threshold1 for GIACs (gravity-induced absorption changes) in Phycomyces to be lower than 25 × 10−3 g (http://file.scirp.org/pdf/JMP_2015082810060783.pdf). In this second paper, we attended measurement of GIAC-spectra. Unexpectedly, during the upwards movement, i.e. the hypergravity phase up to top acceleration values reaching 11.6 g at 35.4 s after liftoff we observed transient GIAC-spectra ranging from 380 to 750 nm. In addition, during the whole acceleration phase of 68.2 s, another component near 700 nm develops which remains stable during the whole “free fall trajectory parabola” for 381.3 s. The subsequent reentry of the rocket leads to extraordinary deceleration values up 37.8 g, completely destroying Phycomyces sporangiophores excluding their spectral measurement. During the microgravity phase and by centrifuge operation we were unable to detect any GIAC-spectra (in contrast to kinetic MDWS-measurements, first paper).展开更多
Various spectroscopic experiments performed on the AIRBUS ZERO G—located in Bordeaux, France—in the years 2002 to 2012 exhibit minute optical reflection/absorption changes (GIACs) as a result of gravitational change...Various spectroscopic experiments performed on the AIRBUS ZERO G—located in Bordeaux, France—in the years 2002 to 2012 exhibit minute optical reflection/absorption changes (GIACs) as a result of gravitational changes between 0 and 1.8 g in various biological species such as maize, oats, Arabidopsis and particularly Phycomyces sporangiophores. During a flight day, the AIRBUS ZERO G conducts 31 parabolas, each of which lasts about three minutes including a period of 22 s of weightlessness. So far, we participated in 11 parabolic flight campaigns including more than 1000 parabolas performing various kinds of experiments. During our campaigns, we observed an unexplainable variability of the measuring signals (GIACs). Using GPS-positioning systems and three dimensional magnetic field sensors, these finally were traced back to the changing earth’s magnetic field associated with the various flight directions. This is the first time that the interaction of gravity and the Earth’ magnetic field in the primary induction process in living system has been observed.展开更多
目的系统评价单核细胞分布宽度(monocyte distribution width,MDW)对成人脓毒症诊断的准确性。方法通过计算机检索知网、维普、万方、PubMed、Embase、Cochrane图书馆等数据库建库至2022年2月发表的有关MDW诊断成人脓毒症的中、英文文...目的系统评价单核细胞分布宽度(monocyte distribution width,MDW)对成人脓毒症诊断的准确性。方法通过计算机检索知网、维普、万方、PubMed、Embase、Cochrane图书馆等数据库建库至2022年2月发表的有关MDW诊断成人脓毒症的中、英文文献。采用诊断准确性研究的质量评价工具(QUADAS-2)对文献进行质量评价。采用Meta-disc 1.4软件进行阈值效应分析、效应量合并及Meta分析,应用Stata 17.0软件,采用Deeks对称性检验评估文献发表偏倚。结果最终有11篇文献纳入Meta分析,结果显示,各研究间存在异质性,采用随机效应模型分析得出合并敏感度、合并特异度、合并阳性似然比(PLR)、合并阴性似然比(NLR)和合并诊断优势比(DOR)分别为0.81[95%可信区间(95%CI)为0.78~0.83]、0.78(95%CI为0.77~0.78)、3.47(95%CI为2.55~4.72)、0.25(95%CI为0.19~0.33)和14.62(95%CI为9.07~23.57),合并拟合受试者工作特征(SROC)曲线下面积(AUC)为0.86,Cochran-Q=0.79。Meta回归分析得出研究类型可能是研究间存在异质性的来源。Deeks对称性检验示,P值为0.39,表明纳入的文献不存在发表偏倚。结论MDW对成人脓毒症具有较好的诊断价值,可作为临床成人脓毒症的诊断依据。展开更多
The acquisition method for planar 67Ga imaging has hardly changed for 30 years. In this study, in order to improve image quality and diagnostic accuracy, we take steps to optimize the acquisition method, and to choose...The acquisition method for planar 67Ga imaging has hardly changed for 30 years. In this study, in order to improve image quality and diagnostic accuracy, we take steps to optimize the acquisition method, and to choose a scatter correction. First, we acquired individual images from the 93 keV, 185 keV, and 300 keV photopeak;then the images were added together and compared to the individual images. Second, we compared results from a low-medium-energy (LME) collimator with those from a conventional medium-energy (ME) collimator. Also, we examined whether to combine the data from all three of the usual window locations (set about 93 keV, 185 keV, and 300 keV) or to use the data from only two. Third, we compared results from a conventional photopeak ± 10% window with those from a photopeak ± 9 keV window. Fourth, for scatter correction we compared results using the triple energy window (TEW) method with those using the multi-photopeak dual window (MDW) method. The phantoms studied were cold rods in a uniform background, and hot spheres within a cylinder containing uniformly radioactive water. The clinical study involved 22 patients with lung lesions. By the comparison by the contrast ratio in cold rods phantom, 15.6% is improved in LME (2 peaks) than ME (3 peaks), and 3.2% is improved in photopeak ± 9 keV than photopeak ± 10%, 10.2% is improved in TEW than MDW. However, the TEW scatter correction method recognized unstable to the contrast ratio in a clinical study. In addition, a body outline might disappear.展开更多
在异质外延薄膜的生长中,应力对薄膜的结构和形貌起着至关重要的作用.理论研究表明,在非公度的薄膜中,应力可以通过形成质量密度波(MDW,Mass Density Wave)的形式释放出来.但是,迄今为止还没有直接的证据证明质量密度波的存在.本文我们...在异质外延薄膜的生长中,应力对薄膜的结构和形貌起着至关重要的作用.理论研究表明,在非公度的薄膜中,应力可以通过形成质量密度波(MDW,Mass Density Wave)的形式释放出来.但是,迄今为止还没有直接的证据证明质量密度波的存在.本文我们用扫描隧道显微镜(STM,Scanning Tunnelling Microscopy)在Bi(001)表面形成的单层红荧烯薄膜中,直接观察到了质量密度波.其表现形式为表面高度有微小的正弦波动,并且分子取向发生周期性畸变.此外,我们还指出质量密度波的形成是由于红荧烯单层膜相对Bi衬底的晶格转动所导致的,由于转动方向不同,质量密度波会呈现出条形或之字形两种不同形状的条纹.展开更多
文摘Under parabolic flight conditions microgravity is not lower than 3 to 5 times 10-2 g. In contrast to parabolic flights, sounding rocket flights are virtually vibrational-free allowing microgravity as low as 10-5 g. Thus, a rotating platform serving as centrifuge allows the precise generation of gravitational forces ranging from 5 to 100 mg (not possible during parabolic flights). On this basis we determined the threshold1 for optical reflection/absorption changes in Phycomyces to be lower than 25 × 10-3 g. This compares well with the threshold determination of gravitropism in Phycomyces on a clinostat centrifuge. Kinetics of gravity-induced absorption changes and gravity as generated by the on-board centrifuge do not coincide but show a distinctive hysteresis with a latency of 4 s (75 mg-ramp, pull-up).
文摘In the first paper of two referring to the TEXUS 50 campaign using micro dual wavelength spectrometers (MDWS) we kinetically determined the threshold1 for GIACs (gravity-induced absorption changes) in Phycomyces to be lower than 25 × 10−3 g (http://file.scirp.org/pdf/JMP_2015082810060783.pdf). In this second paper, we attended measurement of GIAC-spectra. Unexpectedly, during the upwards movement, i.e. the hypergravity phase up to top acceleration values reaching 11.6 g at 35.4 s after liftoff we observed transient GIAC-spectra ranging from 380 to 750 nm. In addition, during the whole acceleration phase of 68.2 s, another component near 700 nm develops which remains stable during the whole “free fall trajectory parabola” for 381.3 s. The subsequent reentry of the rocket leads to extraordinary deceleration values up 37.8 g, completely destroying Phycomyces sporangiophores excluding their spectral measurement. During the microgravity phase and by centrifuge operation we were unable to detect any GIAC-spectra (in contrast to kinetic MDWS-measurements, first paper).
基金supported by grant BW 1025 from the DLR/BMBF(Deutsches Zentrum für Luftund Raumfahrt,and Bundesministerium für Bildung und Forschung).
文摘Various spectroscopic experiments performed on the AIRBUS ZERO G—located in Bordeaux, France—in the years 2002 to 2012 exhibit minute optical reflection/absorption changes (GIACs) as a result of gravitational changes between 0 and 1.8 g in various biological species such as maize, oats, Arabidopsis and particularly Phycomyces sporangiophores. During a flight day, the AIRBUS ZERO G conducts 31 parabolas, each of which lasts about three minutes including a period of 22 s of weightlessness. So far, we participated in 11 parabolic flight campaigns including more than 1000 parabolas performing various kinds of experiments. During our campaigns, we observed an unexplainable variability of the measuring signals (GIACs). Using GPS-positioning systems and three dimensional magnetic field sensors, these finally were traced back to the changing earth’s magnetic field associated with the various flight directions. This is the first time that the interaction of gravity and the Earth’ magnetic field in the primary induction process in living system has been observed.
文摘目的系统评价单核细胞分布宽度(monocyte distribution width,MDW)对成人脓毒症诊断的准确性。方法通过计算机检索知网、维普、万方、PubMed、Embase、Cochrane图书馆等数据库建库至2022年2月发表的有关MDW诊断成人脓毒症的中、英文文献。采用诊断准确性研究的质量评价工具(QUADAS-2)对文献进行质量评价。采用Meta-disc 1.4软件进行阈值效应分析、效应量合并及Meta分析,应用Stata 17.0软件,采用Deeks对称性检验评估文献发表偏倚。结果最终有11篇文献纳入Meta分析,结果显示,各研究间存在异质性,采用随机效应模型分析得出合并敏感度、合并特异度、合并阳性似然比(PLR)、合并阴性似然比(NLR)和合并诊断优势比(DOR)分别为0.81[95%可信区间(95%CI)为0.78~0.83]、0.78(95%CI为0.77~0.78)、3.47(95%CI为2.55~4.72)、0.25(95%CI为0.19~0.33)和14.62(95%CI为9.07~23.57),合并拟合受试者工作特征(SROC)曲线下面积(AUC)为0.86,Cochran-Q=0.79。Meta回归分析得出研究类型可能是研究间存在异质性的来源。Deeks对称性检验示,P值为0.39,表明纳入的文献不存在发表偏倚。结论MDW对成人脓毒症具有较好的诊断价值,可作为临床成人脓毒症的诊断依据。
文摘The acquisition method for planar 67Ga imaging has hardly changed for 30 years. In this study, in order to improve image quality and diagnostic accuracy, we take steps to optimize the acquisition method, and to choose a scatter correction. First, we acquired individual images from the 93 keV, 185 keV, and 300 keV photopeak;then the images were added together and compared to the individual images. Second, we compared results from a low-medium-energy (LME) collimator with those from a conventional medium-energy (ME) collimator. Also, we examined whether to combine the data from all three of the usual window locations (set about 93 keV, 185 keV, and 300 keV) or to use the data from only two. Third, we compared results from a conventional photopeak ± 10% window with those from a photopeak ± 9 keV window. Fourth, for scatter correction we compared results using the triple energy window (TEW) method with those using the multi-photopeak dual window (MDW) method. The phantoms studied were cold rods in a uniform background, and hot spheres within a cylinder containing uniformly radioactive water. The clinical study involved 22 patients with lung lesions. By the comparison by the contrast ratio in cold rods phantom, 15.6% is improved in LME (2 peaks) than ME (3 peaks), and 3.2% is improved in photopeak ± 9 keV than photopeak ± 10%, 10.2% is improved in TEW than MDW. However, the TEW scatter correction method recognized unstable to the contrast ratio in a clinical study. In addition, a body outline might disappear.
文摘在异质外延薄膜的生长中,应力对薄膜的结构和形貌起着至关重要的作用.理论研究表明,在非公度的薄膜中,应力可以通过形成质量密度波(MDW,Mass Density Wave)的形式释放出来.但是,迄今为止还没有直接的证据证明质量密度波的存在.本文我们用扫描隧道显微镜(STM,Scanning Tunnelling Microscopy)在Bi(001)表面形成的单层红荧烯薄膜中,直接观察到了质量密度波.其表现形式为表面高度有微小的正弦波动,并且分子取向发生周期性畸变.此外,我们还指出质量密度波的形成是由于红荧烯单层膜相对Bi衬底的晶格转动所导致的,由于转动方向不同,质量密度波会呈现出条形或之字形两种不同形状的条纹.
