Effects of spaceflight and simulated microgravity on microbial growth and secondary metabolism

Spaceflight and ground-based microgravity analog experiments have suggested that microgravity can affect microbial growth and metabolism. Although the effects of microgravity and its analogs on microorganisms have been studied for more than 50 years, plausible conflicting and diverse results have frequently been reported in different experiments, especially regarding microbial growth and secondary metabolism. Until now, only the responses of a few typical microbes to microgravity have been investigated; systematic studies of the genetic and phenotypic responses of these microorganisms to microgravity in space are still insufficient due to technological and logistical hurdles. The use of different test strains and secondary metabolites in these studies appears to have caused diverse and conflicting results. Moreover, subtle changes in the extracellular microenvironments around microbial cells play a key role in the diverse responses of microbial growth and secondary metabolisms. Therefore, "indirect" effects represent a reasonable pathway to explain the occurrence of these phenomena in microorganisms. This review summarizes current knowledge on the changes in microbial growth and secondary metabolism in response to spaceflight and its analogs and discusses the diverse and conflicting results. In addition, recommendations are given for future studies on the effects of microgravity in space on microbial growth and secondary metabolism.

论Manned Spaceflight的文体特征及其翻译策略——以被动句为研究案例

Manned Spaceflight一文陈述客观准确,逻辑结构严密,专业术语性强,语气正式。其文体特征包括被动语态、名词化、非谓语、专业词汇、割裂、并列、无灵主语、介词、长句、省略等。以被动句为例,通过Manned Spaceflight中翻译实践发现,被动句翻译为主动句、被动句和无主句时,翻译策略各不相同。

Analyses on schedule-cost coefficient correlation of spaceflight project based on historical statistics and its application

When analyze the uncertainty of the cost and the schedule of the spaceflight project, it is needed to know the value of the schedule-cost correlation coefficient. This paper deduces the schedule distribution, considering the effect of the cost, and proposes the estimation formula of the correlation coefficient between the in（schedule） and the cost. On the basis of the fact and Taylor expansion, the relation expression between the schedule-cost correlation coefficient and the in-schedule-cost correlation coefficient is put forward. By analyzing the value features of the estimation formula of the in-schedule-cost correlation coefficient, the general rules are proposed to ascertain the value of the schedule-cost correlation coefficient. An example is given to demonstrate how to approximately amend the schedule-cost correlation coefficient based on the historical statistics, which reveals the traditional assigned value is inaccurate. The universality of this estimation method is analyzed.

Mutagenic Effects of Spaceflight Treatment on the Second-Generation Seeds of Alfalfa

[ Objective] To explore the effects of spaceflight on the second-generation seeds of alfalfa and provide a theoretical basis for mutation breeding. [Method] The seeds of Medicago stavia L. lines no. 1, no. 2 and no. 4 were carried into space by the Shijian-8 seed breeding satellite for a 15-d spaceflight treatment. After returning to the ground, seedlings were transplanted to field. Traits of the second-generation seeds of alfalfa were evaluated. [Result] The 1 000-grain weight of the second-generation seeds were 5% -9% significantly higher than that the control （P 〈 0.05）. The germination rate, seedling weight, shoot length and root length were significantly increased （P 〈 0.05）. The hard seed rate and the rate of moldy seeds were significantly decreased （ P 〈 0.05）. However, the rate of dead seeds was increased. [ Conclusion] Spaceflight treatment has positive mutagenic effects on the second-generation seeds of alfalfa.

Speed kills: Highly relativistic spaceflight would be fatal for passengers and instruments

Highly relativistic speeds are desirable for interstellar travel. Relativistic time dilation would reduce the subjective duration of the trip for the travelers, so that they can cover galaxy-scale distances in a reasonable amount of personal time. Unfortunately, as spaceship velocities approach the speed of light, interstellar hydrogen H, although only present at a density of approximately 1.8 atoms/cm3, turns into intense radiation that would quickly kill passengers and destroy electronic instrumentation. In addition, the energy loss of ionizing radiation passing through the ship’s hull represents an increasing heat load that necessitates large expenditures of energy to cool the ship. Stopping or diverting this flux, either with material or electromagnetic shields, is a daunting problem. Going slow to avoid severe H irradiation sets an upper speed limit of v ~ 0.5 c. This velocity only gives a time dilation factor of about 15%, which would not substantially assist galaxy-scale voyages. Diffuse interstellar H atoms are the ultimate cosmic space mines and represent a formidable obstacle to interstellar travel.

Manned Spaceflight Ancient Dream, Modern Attempt

China was first in the world to invent rockets, and the first "astronaut" was also Chinese. In the late 14th century a man named Wanhu had himself tied to a special chair, the back of which was fitted with 47 prototype rockets, while

Estimation Method of Schedule-cost Correlation Coefficient of Spaceflight Project

To evaluate the cost risk and the schedule risk of the spaceflight project,the schedule-cost(S-C) correlation coefficient is directly appointed according to the experts' experience usually.This paper deduces SDMCU(the schedule distribution model considering the effect of the cost uncertainty),and then proposes the approximate formula to estimate the ln(S)-C correlation coefficient based on the models of SDMCU and CDMSU(the cost distribution model considering the effect of the schedule uncertainty).Furthermore,an approximate relationship expression of the S-C and the ln(S)-C correlation coefficients is put forward according to general facts and the Taylor expansion,and advanced by means of mass numerical validation is the general rule of obtaining the estimation value of the schedule-cost correlation coefficient based on the historical data.

Remarkable Achievements of China’s Manned Spaceflight Project

On September 21,1992, the feasibility report on implementing China's Manned Spaceflight Project was approved and a three-step development strategy was also determined. From then on, China's Manned Spaceflight Project has developed rapidly.

LM-2F: A Great Launch Vehicle for China's Manned Spaceflight

The LM-2F launch vehicle is China's first launch carrier developed for China's Manned Space Program,which is one of the most important parts of the Program.It is developed from the LM-2E launch vehicle,with addition of two new systems,an escape system and a fault detection system.

关于“Some Theoretical Problems of the Spaceflight Mechanics”(Ⅲ)

改善了文献［２］的前言

关于“Some Theoretical Problems of the Spaceflight Mechanics” (Ⅳ)

本文完善了文献［１］的一些结果。

Genome and clonal hematopoiesis stability contrasts with immune,cfDNA,mitochondrial,and telomere length changes during short duration spaceflight

Background The Inspiration4(I4)mission,the first all-civilian orbital flight mission,investigated the physiological effects of short-duration spaceflight through a multi-omic approach.Despite advances,there remains much to learn about human adaptation to spaceflight's unique challenges,including microgravity,immune system perturbations,and radiation exposure.Methods To provide a detailed genetics analysis of the mission,we collected dried blood spots pre-,during,and post-flight for DNA extraction.Telomere length was measured by quantitative PCR,while whole genome and cfDNA sequencing provided insight into genomic stability and immune adaptations.A robust bioinformatic pipeline was used for data analysis,including variant calling to assess mutational burden.Result Telomere elongation occurred during spaceflight and shortened after return to Earth.Cell-free DNA analysis revealed increased immune cell signatures post-flight.No significant clonal hematopoiesis of indeterminate potential(CHIP)or whole-genome instability was observed.The long-term gene expression changes across immune cells suggested cellular adaptations to the space environment persisting months post-flight.Conclusion Our findings provide valuable insights into the physiological consequences of short-duration spaceflight,with telomere dynamics and immune cell gene expression adapting to spaceflight and persisting after return to Earth.CHIP sequencing data will serve as a reference point for studying the early development of CHIP in astronauts,an understudied phenomenon as previous studies have focused on career astronauts.This study will serve as a reference point for future commercial and non-commercial spaceflight,low Earth orbit(LEO)missions,and deep-space exploration.

自修复弹性体材料的研究进展及应用

综述了基于外援型和本征型2种体系的弹性体材料自修复机理和自修复技术在弹性体材料中的应用,并展望了自修复弹性体材料在载人航天领域的应用前景。

载人航天人机交互界面色彩设计方法研究

目的对载人航天人机交互界面的色彩设计方法流程进行了梳理和分析。方法遵循“以人为中心”的设计原则,从色彩空间与模型、色彩设计与人因、航天色彩设计范围、载人航天器色彩设计模型,以及载人航天器色彩设计与人因评价体系等方面,对载人航天器人机交互界面色彩设计方法流程体系进行了探讨。结果构建了载人航天色彩设计模型,阐述了完整的载人航天色彩设计方法流程体系。结论针对载人航天人机交互色彩设计方法的研究为航天员在轨环境中的生活品质及工作效能等相关领域的提高提供了有力支持,进一步增强了航天领域色彩设计与人因工程的重要性。

药食同源理论及其在航天营养健康研究中的应用

载人航天飞行中面临的重力场变化、辐射、狭小空间孤闭隔离、噪声及生物节律变化等航天特因环境给维持航天员机体营养健康带来了挑战。根据载人航天实践,综述了航天特因环境下机体适应性变化,阐述了药食同源在航天营养健康保障中的应用预先研究现状,分析并提出了药食同源在支持未来载人深空探测方面的潜在应用价值。

失重环境下航天员平衡控制专项防护策略分析

航天飞行面临的失重会引起航天员运动感觉减弱,进而影响姿势维持和平衡控制,从而限制了出舱活动或着陆等紧急突发状况时航天员快速脱离险境的能力,严重影响航天任务的完成并危及航天员的安全。当前基于运动锻炼的失重对抗措施可在一定程度上有效缓解失重所致的骨骼、肌肉及心血管问题,但并不能有效防止航天飞行后的运动感觉功能紊乱。因此,需要新的失重对抗专项体能训练措施以预防长期空间飞行后人体平衡控制能力的下降。通过对以往航天飞行及模拟失重研究结果的回顾,笔者系统分析了人体平衡控制的影响因素,并对比体育领域平衡控制提升专项体能训练方案提出基于体医融合的失重环境防护策略。肌肉张力、触觉和本体感觉反馈调节在人体姿势平衡和动作控制中起重要作用,而航天失重环境下人体重力负荷的卸载会大大减少上述感觉的输入输出反馈调节,导致平衡功能障碍。在航天飞行中通过纵轴轴向负荷加载、触觉反馈增强和基于不稳定机械应力刺激的本体感觉响应等航天失重环境下航天员专项体能训练,或许可以改善飞行后的平衡控制功能障碍。

载人飞行航天员处置突发故障的能力训练需求分析与方法探索

载人飞行中处置突发故障的能力是航天员应具备的重要能力之一。介绍了中国载人飞行空间站任务组合体应急与故障的分类,利用胜任力洋葱模型从组合体应急与故障处理的内容、任务要求等方面对航天员具备的胜任能力由内到外分层剖析,得出组合体应急与故障处理胜任能力各元素,根据组合体应急与故障处理航天员应具备的能力特点构建了组合体应急与故障处理能力的结构模型;对训练的方法进行研究,并从训练的途径和举措方面出发对需要关注的问题开展了研究。通过多次在轨飞行任务航天员应对各类故障的处置情况及失压失火在轨演练中航天员的表现,验证了训练方法的科学合理性。

空间啮齿类动物培养装置及实验技术研究进展

空间动物实验是人类空间生命科学研究的重要组成部分.一直以来,空间动物实验为探索地球生物体在航天环境中的生命现象及活动规律、支持载人航天的可持续性发展做出了重要贡献.随着航天工程的发展,航天员在空间驻留的时间越来越长,为解决人类在空间旅行中的健康问题,各国先后开展了空间啮齿类动物实验,研究空间环境给生命体带来的影响,为人类空间飞行提供重要的生理和医学数据.本文研究了国外主流的空间啮齿类动物培养装置,根据各类装置培养动物的存活情况及死亡原因,提出装置的不足与可改进之处;深入分析空间啮齿类动物实验发射前、在轨、返回地面阶段的相关实验技术,为中国空间啮齿类动物培养装置设计及动物实验提供参考.

载人航天商业化的国际损害责任制度:困境与应对

载人航天商业化的发展需要平衡外层空间的公共性和商业载人航天的私营性,国际损害责任制度对管控商业载人航天的成本和风险至关重要。国际外空法对国际损害责任进行了一般性、原则性规定,部分航天国家在国内法中对商业载人航天的损害责任予以明确。基于外空领域的现有责任规则,构建国际损害责任制度面临着责任主体和索赔主体不明、过失作为例外要件存在不合理、国际保险标准难统一、责任分配制度待完善的困境。对此,可考虑通过关联性确认责任主体和索赔主体、对损害统一适用绝对责任、引入强制责任保险、形成双重责任制度,为国家载人航天商业化发展提供制度构建思路;同时,促进国际社会达成共识,推动人类命运共同体理念在外空领域的进一步实现。

航天诱变育种对金针菇遗传和药用品质性状的影响

[目的]本文旨在利用航天诱变技术,选育获得金针菇特色优质种质资源。[方法]对金针菇菌株F3-1进行航天诱变处理,通过拮抗试验、分子标记试验和活性物质测定等对航天诱变菌株进行筛选鉴定及遗传变异多样性分析,并筛选活性物质含量高的菌株。[结果]拮抗试验初筛获得7株与出发菌株存在拮抗现象的变异株。分子标记(ISSR、RAPD、SRAP)聚类分析结果表明,7个诱变菌株与出发菌株的遗传相似系数为0.694~0.962,且在遗传相似系数为0.800时可分为3个类群。诱变菌株与出发菌株的菌丝生长速度、生物量、总酚、类黄酮、多糖和麦角硫因等指标的变异系数为7.68%~38.97%,遗传多样性指数H′为1.53~2.00。其中,多糖含量的变异系数最高,受诱变影响大;总酚的遗传多样性指数最大,诱变类型丰富。生物学特性聚类分析显示,在遗传距离为3.16时分为3个类群。最终筛选获得2株活性物质含量高的菌株(T2和T5),其中T2菌株生长速度、生物量和活性物质等均优于出发菌株,而T5菌株主要表现为高多糖含量菌株,其多糖含量比出发菌株提高114.70%(P<0.01)。[结论]航天诱变处理的金针菇菌株存在丰富的遗传变异多样性,是新品种选育的优异种质资源。