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排序方式: 共有283条查询结果,搜索用时 31 毫秒
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32.
Kaori Takemura Rina Watanabe Ryuji Kameishi Naoya Sakaguchi Hiroyuki Kamachi Atsushi Kume Ichirou Karahara Yuko T. Hanba Tomomichi Fujita 《Microgravity science and technology》2017,29(6):467-473
The photosynthetic and anatomical responses of bryophytes to changes in gravity will provide crucial information for estimating how these plant traits evolved to adapt to changes in gravity in land plant history. We performed long-term hypergravity experiments at 10g for 4 and 8 weeks using the moss Physcomitrella patens with two centrifuges equipped with lighting systems that enable long-term plant growth under hypergravity with irradiance. The aims of this study are (1) to quantify changes in the anatomy and morphology of P. patens, and (2) to analyze the post-effects of hypergravity on photosynthesis by P. patens in relation to these changes. We measured photosynthesis by P. patens for a population of gametophores (e.g., canopy) in Petri dishes and plant culture boxes. Gametophore numbers increased by 9% for a canopy of P. patens, with 24–27% increases in chloroplast sizes (diameter and thickness) in leaf cells. In a canopy of P. patens, the area-based photosynthesis rate (A canopy) was increased by 57% at 10g. The increase observed in A canopy was associated with greater plant numbers and chloroplast sizes, both of which involved enhanced CO2 diffusion from the atmosphere to chloroplasts in the canopies of P. patens. These results suggest that changes in gravity are important environmental stimuli to induce changes in plant growth and photosynthesis by P. patens, in which an alteration in chloroplast size is one of the key traits. We are now planning an ISS experiment to investigate the responses of P. patens to microgravity. 相似文献
33.
Xiaohe Tian Cesare De Pace Lorena Ruiz-Perez Bo Chen Rina Su Mingzhu Zhang Ruilong Zhang Qiong Zhang Qin Wang Hongping Zhou Jieying Wu Zhongping Zhang Yupeng Tian Giuseppe Battaglia 《Advanced materials (Deerfield Beach, Fla.)》2020,32(39):2003901
The visualization of microtubules by combining optical and electron microscopy techniques provides valuable information to understand correlated intracellular activities. However, the lack of appropriate probes to bridge both microscopic resolutions restricts the areas and structures that can be comprehended within such highly assembled structures. Here, a versatile cyclometalated iridium (III) complex is designed that achieves synchronous fluorescence–electron microscopy correlation. The selective insertion of the probe into a microtubule triggers remarkable fluorescence enhancement and promising electron contrast. The long-life, highly photostable probe allows live-cell super-resolution imaging of tubulin localization and motion with a resolution of ≈30 nm. Furthermore, correlative light–electron microscopy and energy-filtered transmission electron microscopy reveal the well-associated optical and electron signal at a high specificity, with an interspace of ≈41 Å of microtubule monomer in cells. 相似文献
34.
Spencer B. Backus Rina Onishi Andrew Bocklund Andrew Berg Eric D. Contreras Aaron Parness 《野外机器人技术杂志》2020,37(6):972-986
We present the design and experimental results for the JPL‐Nautilus Gripper, a 16‐finger highly underactuated microspine gripper for use in the deep ocean. The gripper can grasp objects from 10 to 30 cm in size and anchor to flat and curved rocky surfaces (i.e., cliff faces and seamounts). Laboratory results demonstrated an anchoring capability of greater than 450 N on rough rocks in both shear and normal loading directions. Deployment on the Hercules ROV (remotely operated vehicle) aboard the E/V Nautilus on three deep‐ocean dives verified performance at depths up to to 2,100 m with approximately 100 N loads applied through the ROV's thrusters, including moment loads. The gripper also serves as a development unit for future robotic tools that will include a coring drill in the center of the gripper, as previously demonstrated in non‐ocean environments with microspine grippers. Such a tool will facilitate the collection of geologic samples from the deep ocean using more agile and cost‐effective systems. 相似文献
35.
Alloy ingots with nominal composition, Al92−x
Ni8La
x
(x = 4 to 6) and Al94−x
Ni6La
x
(x = 6, 7), were prepared by induction melting in a purified Ar atmosphere. Each ingot was inductively re-melted and rapidly
solidified ribbons were obtained by ejecting the melt onto a rotating copper wheel in an argon atmosphere. The crystallization
behaviour of melt-spun amorphous ribbon was investigated by means of differential scanning calorimetry (DSC), X-ray diffractometry
and transmission electron microscopy. DSC showed that Al86Ni8La6 alloy undergoes a three-stage and rest of the alloys undergo a two-stage crystallization process upon heating. The phases
responsible for each stage of crystallization were identified. During the first crystallization stage fcc-Al precipitates for low La-containing alloys and for higher La-containing alloys a bcc metastable phase precipitates. The second crystallization stage is due to formation of intermetallic compounds along with
fcc-Al. Microhardness of all the ribbons was examined at different temperatures and correlated with structural evolutions. Precipitation
strengthening of nano-size fcc-Al is responsible for maximum hardness in these annealed alloys. 相似文献
36.
37.
Rina Aharoni Raya Eilam Shaul Lerner Efrat Shavit-Stein Amir Dori Joab Chapman Ruth Arnon 《International journal of molecular sciences》2021,22(24)
Axonal and neuronal pathologies are a central constituent of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), induced by the myelin oligodendrocyte glycoprotein (MOG) 35–55 peptide. In this study, we investigated neurodegenerative manifestations in chronic MOG 35–55 induced EAE and the effect of glatiramer acetate (GA) treatment on these manifestations. We report that the neuronal loss seen in this model is not attributed to apoptotic neuronal cell death. In EAE-affected mice, axonal damage prevails from the early disease phase, as revealed by analysis of neurofilament light (NFL) leakage into the sera along the disease duration, as well as by immunohistological examination. Elevation of interstitial glutamate concentrations measured in the cerebrospinal fluid (CSF) implies that glutamate excess plays a role in the damage processes inflicted by this disease. GA applied as a therapeutic regimen to mice with apparent clinical symptoms significantly reduces the pathological manifestations, namely apoptotic cell death, NFL leakage, histological tissue damage, and glutamate excess, thus corroborating the neuroprotective consequences of this treatment. 相似文献
38.
两种放牧方式对绒山羊肉抗氧化系统的影响 总被引:1,自引:0,他引:1
以草场放牧、山地放牧两种方式下的绒山羊背最长肌为实验材料,测定背最长肌的色泽、肌红蛋白含量、 丙二醛含量、氧合肌红蛋白相对含量、高铁肌红蛋白相对含量、抗氧化酶活力和总抗氧化能力等指标并进行比较分 析。结果表明:草场放牧绒山羊肉的红度、过氧化氢酶活力、谷胱甘肽过氧化物酶活力和自由基清除率均显著高于 山地放牧(P<0.05);草场放牧绒山羊肉亮度、黄度、高铁肌红蛋白相对含量、丙二醛含量均显著低于山地放牧 (P<0.05),但两种放牧方式绒山羊肉的肌红蛋白含量、氧合肌红蛋白相对含量、超氧化物歧化酶活力和总抗氧 化能力没有显著差异(P>0.05)。在草场放牧条件下,绒山羊能摄食大量绿色牧草,并且有适宜的运动量,增加 了抗氧化酶的活力和肉色稳定性,自由基的产生和清除达到了平衡,从而使其肉品的抗氧化能力高于山地放牧。 相似文献
39.
Shiori Mori Rina Fujiwara-Tani Shingo Kishi Takamitsu Sasaki Hitoshi Ohmori Kei Goto Chie Nakashima Yukiko Nishiguchi Isao Kawahara Yi Luo Hiroki Kuniyasu 《International journal of molecular sciences》2021,22(15)
β-Casomorphin-7 (BCM) is a degradation product of β-casein, a milk component, and has been suggested to affect the immune system. However, its effect on mucosal immunity, especially anti-tumor immunity, in cancer-bearing individuals is not clear. We investigated the effects of BCM on lymphocytes using an in vitro system comprising mouse splenocytes, a mouse colorectal carcinogenesis model, and a mouse orthotopic colorectal cancer model. Treatment of mouse splenocytes with BCM in vitro reduced numbers of cluster of differentiation (CD) 20+ B cells, CD4+ T cells, and regulatory T cells (Tregs), and increased CD8+ T cells. Administration of BCM and the CD10 inhibitor thiorphan (TOP) to mice resulted in similar alterations in the lymphocyte subsets in the spleen and intestinal mucosa. BCM was degraded in a concentration- and time-dependent manner by the neutral endopeptidase CD10, and the formed BCM degradation product did not affect the lymphocyte counts. Furthermore, degradation was completely suppressed by TOP. In the azoxymethane mouse colorectal carcinogenesis model, the incidence of aberrant crypt foci, adenoma, and adenocarcinoma was reduced by co-treatment with BCM and TOP. Furthermore, when CT26 mouse colon cancer cells were inoculated into the cecum of syngeneic BALB/c mice and concurrently treated with BCM and TOP, infiltration of CD8+ T cells was promoted, and tumor growth and liver metastasis were suppressed. These results suggest that by suppressing the BCM degradation system, the anti-tumor effect of BCM is enhanced and it can suppress the development and progression of colorectal cancer. 相似文献
40.