In vitro effects of simulated microgravity on Sertoli cell function

With the advent of space flights questions concerning the effects of microgravity (0×G) on human reproductive physiology have received great attention. The aim of this study was to evaluate the influence of 0×G on Sertoli cells. A Sertoli cell line from mouse testis (42GPA9) was analyzed for cytoskeletal and Sex Hormone Binding Globilin (SHBG) changes by immunohistochemistry, for antioxidant content by RT-PCR and for culture medium lactate concentrations by protein chemistry. Cells were cultured for 6, 24 and 48 h on a three-dimensional Random Positioning Machine (3D-RPM); static controls (1×G) were positioned on the supporting frame. At the end of each experiment, cultured cells were either fixed in paraformaldehyde or lysed and RNA-extracted or used for culture medium lactate measurements as needed. At 0×G, Sertoli cytoskeleton became disorganized, microtubules fragmented and SHBG undetectable already after 24 h, with alterations worsening by 48 h. It was evident that various antioxidant systems appreciably increased during the first 24 h but significantly decreased at 48 h. No changes occurred in the 1×G samples. Initially, 0×G seemed to disturb antioxidant protection strategies allowing the testes to support sperm production, thus generating an aging-like state of oxidative stress. Lactate production at 0×G slightly decreased after 24 h. Further experiments are needed in space to investigate upon steroidogenesis and germ cell differentiation within the testis, to rule out male infertility as a possible consequence, which could be a problem, as life expectancy increases.     

SLUCUBE: Innovative high performance nanosatellite science and technology demonstration mission

The Space Systems Research Laboratory (SSRL) at Saint Louis University is developing SLUCUBE nanosatellite as part of the space mission design program. The objective of the mission is to demonstrate space capability of high performance nanosatellite components that has been developed at SSRL for the past three years. The objective of the program is to provide extremely low-cost and rapid access to space for scientists and commercial exploitation using commercial-off-the-shelf components. SLUCUBE is a double CubeSat with dimensions 10×10×20 cm and a mass of 2 kg. This nanosatellite features suite of technology demonstration components to enlarge the capability of space mission for such class of spacecrafts. The primary mission of SLUCUBE is to test and demonstrate several enabling technologies by flying a number of university developed high performance components. This paper describes the new developed technologies by providing details of specific components developed along with the R&D efforts and laboratory facilities. A brief discussion about the student involvement and educational benefits will also be presented.     

低压储能的升浮一体飞行器总体参数研究

升浮一体飞行器是一种综合了太阳能无人机和平流层飞艇特点的新型临近空间飞行器,是航空航天领域研究的热点,可再生燃料电池是升浮一体飞行器最有发展前景的储能装置。针对现有燃料电池中氢气和氧气存储方式的缺陷,充分利用升浮一体飞行器巨大的机身体积,提出了采用低压气囊储气的燃料电池方案,建立了升浮一体飞行器总体参数计算模型,提出常规燃料电池和气囊储气燃料电池的理论计算方法。研究了不同储气方式对升浮一体飞行器的能源系统以及飞行器总体参数的影响。研究表明,采用低压储气方法后,氢气的质量储气密度可提高至13.0%,燃料电池存储能量为1 489.7 kWh条件下,能量密度可达到1 000 Wh/kg以上,对减小升浮一体飞行器总重和外形尺寸、提高飞行器载荷能力有显著作用。     

匀转速逆合成孔径雷达的越距离徙动补偿

针对ISAR系统中的匀转速目标,本文提出了一种有效的校正由目标均转速旋转引起的越距离徙动(MTRC)的方法,对方位向上越距离徙动进行校正。它采用基于PD算法的Radon变换在方位向上得到精确的二次相位系数估计值,然后直接在时域上对越距离徙动校正,获得了更高的分辨率。Outlier-delete算法是一种在时域校正方位向越距离徙动的算法,在高信噪比条件下可以实现很好的聚焦效果,而在低信噪比条件下,该算法会出现严重误估计,导致聚焦失败。本文提出的Radon-PD算法具有很好的抗噪性,通过仿真并与Outlier-delete算法进行性能比较,验证了算法的有效性和可行性。     

模拟微重力对人骨髓间充质干细胞向成骨细胞分化中细胞信号通路影响的分析

通过模拟来研究微重力对hMSC向成骨细胞分化的影响,并利用相关信号通路的激活剂或抑制剂来调节这一分化过程.研究结果表明,在成骨细胞分化诱导条件下,微重力降低了hMSC向成骨细胞定向分化的能力,并且成骨细胞标记性基因的表达明显降低, Runt相关转录因子2(Ruax2)的表达受到抑制.相反,过氧化物酶体增殖激活受体γ(PPARγ2)的表达则增加.同时,微重力也降低了ERK的磷酸化水平,而增加了p38MAPK的磷酸化水平.使用p38MAPK的抑制剂SB203580能够抑制p38MAPK的磷酸化,但不能降低PPARγ2的表达水平.骨形态发生蛋白(BMP)能增加Runx2的表达水平.成纤维细胞生长因子2(FGF2)增加了ERK的磷酸化水平,但也不能显著增加成骨细胞标记性基因的表达水平.采用BMP,FGF2和SB203580三种因子组合来调控微重力下的成骨细胞分化能力,结果表明三者的协同作用能显著逆转微重力对成骨细胞定向分化的生物学效应.研究结果还说明,模拟微重力应该是通过不同的细胞信号通路来抑制成骨细胞分化和提升脂肪细胞分化的.      

MEO卫星太阳电池在轨衰降特性分析

通过MEO卫星在轨遥测数据的统计,从太阳电池阵输出总功率、输出总电流,太阳电池的短路电流、开路电压等方面,对我国发射入轨的第一颗MEO卫星的硅太阳电池阵在轨衰降特性进行了分析,结果表明:输出总功率、总电流与短路电流在第一个周期衰降率较大,开路电压衰降呈线性趋势。文章的分析结果可为后续MEO卫星太阳电池阵设计提供参考。     

电沉积太阳电池用Cu(In,Ga)Se2薄膜

在Mo基底上,采用恒电位法从含有CuCl2、InCl3、GaCl3、H2SeO3、柠檬酸的水溶液中电沉积制备Cu(In,Ga)Se2薄膜,用HCl调节pH值为2.5,并对沉积薄膜400℃左右Ar气氛中退火20min。对退火前后的膜进行X射线衍射,扫描电镜和能谱分析仪分析,结果表明,电沉积制备的Cu(In,Ga)Se2薄膜为黄铜矿结构,退火后,共沉积薄膜的结晶度提高,晶粒尺寸增加,Se含量减少。     

应用绿色半导体量子点进行乳腺癌原位成像

乳腺癌是癌症中引起妇女死亡的首要因素。本文采用绿色量子点作为荧光显色材料，建立了一种用于早期乳腺癌诊断的原位成像技术。利用生物素标记的抗HER2／neu抗体与乳腺癌细胞表面表达的HER2结合的特点，然后用偶联绿色量子点的链霉亲和素作为荧光检测标记物，与HER2抗原抗体复合物中的生物素发生特异结合，检测出乳腺癌细胞的存在。结果表明，在荧光显微镜下用绿色量子点原位显色的乳腺癌细胞，相对有机染料组显色亮度增强，故检测灵敏度有所提高。     

Effect of microgravity on primordial germ cells (PGCs) in silk chicken offspring (Gallus gallus domesticus)

Primordial germ cells (PGCs), precursors of germline cells, display a variety of antigens during their migration to target gonads. Here, we used silk chicken offspring (Gallus gallus domesticus) embryos subjected to space microgravity to investigate the influence of microgravity on PGCs. The ShenZhou-3 unmanned spaceship carried nine fertilized silk chicken eggs, named the flight group, returned to Earth after 7 days space flight. And the control group has the same clan with the flight group. PGCs from flight and control group silk chicken offspring embryos were examined during migration by using two antibodies (2C9 and anti-SSEA-1), in combination with the horseradish peroxidase detection system, and using periodic acid-Schiff’s solution (PAS) reaction. After incubation for about 30 h, SSEA-1 and 2C9 positive cells were detected in the germinal crescent of flight and control group silk chicken offspring embryos. After incubation of eggs for 2–2.5 days, SSEA-1 and 2C9 positive cells were detected in embryonic blood vessels of flight and control group silk chicken offspring embryos. After incubation of eggs for 5.5 days, PGCs in the dorsal mesentery and gonad could also be identified in flight and control group silk chicken offspring embryos by using SSEA-1 and 2C9 antibodies. Based on location and PAS staining, these cells were identified as PGCs. Meanwhile, at the stage of PGCs migration and then becoming established in the germinal ridges, no difference in SSEA-1 or 2C9 staining was detected between female and male PGCs in flight and control group silk chicken offspring embryos. Although there were differences in the profiles of PGC concentration between male and female embryos during the special circulating stage, changing profile of PGCs concentration was similar in same sex between flight and control group offspring embryos. We concluded that there is little effect on PGCs in offspring embryos of microgravity-treated chicken and that PGC development appears to be normal.