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If humans ever start to live permanently in space, assisted reproductive technology using preserved spermatozoa will be important for producing offspring; however, radiation on the International Space Station (ISS) is more than 100 times stronger than that on Earth, and irradiation causes DNA damage in cells and gametes.Here we examined the effect of space radiation on freeze-dried mouse spermatozoa held on the ISS for 9 mo at -95°C, with launch and recovery at room temperature. DNA damage to the spermatozoa and male pronuclei was slightly increased, but the fertilization and birth rates were similar to those of controls. Nextgeneration sequencing showed only minor genomic differences between offspring derived from space-preserved spermatozoa and controls, and all offspring grew to adulthood and had normal fertility. Thus, we demonstrate that although space radiation can damage sperm DNA, it does not affect the production of viable offspring after at least 9 mo of storage on the ISS.International Space Station | preservation | freeze-dry | spermatozoa | fertilization S ince the "space dog" Laika (Лайка) was first placed into orbit in 1957 (1), many humans and animals have been to space or stayed on the International Space Station (ISS) for more than 6 mo. In the future, humans likely will live on largescale space stations or in other space habitats for several years or even over many generations. At that time, assisted reproductive technology (ART) likely will be used to produce humans in space habitats, given that the use of ART by infertile couples has increased year by year and that ART can be performed with cryopreserved spermatozoa or embryos (2, 3). In a similar way, domestic animals likely will be generated by artificial insemination (AI) in space, because many domestic animals are already produced by AI using long-term cryopreserved spermatozoa (4). In addition, genetic diversity is very important for maintaining a species, especially in small colonies, and this could be achieved by cryopreserving a diverse range of gamete cells. The environment in space is very different from that on Earth, however, including high levels of space radiation and microgravity, and the effects of these factors on mammalian reproduction are largely unknown. Although with current technology, producing offspring in such an environment can be difficult or dangerous (5), the study of reproduction in space is a very important subject for our future.So far, the effects of microgravity on early development have been studied using sea urchins, fish, amphibians, and birds (6-12). These studies have concluded that microgravity does not prevent animal reproduction. However, because of the difficulty in maintaining mammals and performing experiments in space, studies of mammal reproduction in space have not progressed as well as in other animals, and only a few papers have been published (13-18). Those studies and our previous study (19) have suggested that mammalian reproduction in space under conditions of microgravity cannot be easil...

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SUMMARYOnline hybrid tests (called the online tests), particularly when combined with substructuring techniques, are able to conduct large-scale tests. An extension of this technique is to combine multiple loading tests conducted in remote locations and to integrate the tests with large numerical analysis codes. In this study, a new Internet online test system is developed in which a physical test is conducted in one place, the associated numerical analysis is performed in a remote location, and the two locations communicate over the Internet. To implement the system, a technique that links test and analysis domains located at di erent places is proposed, and an Internet data exchange interface is devised to allow data communication across Internet. A practical method that utilizes standard protocols implemented by operating systems for sharing ÿles and folders is adopted to ensure stable and robust communication between remotely located servers that commonly protect themselves by strict ÿrewalls. To combine the online test with a ÿnite element program formulated in an incremental form and adopting an implicit integration scheme, a tangent sti ness prediction procedure is proposed. In this procedure, a tangent sti ness is estimated based on a few previous steps of experimental data. Using the system devised, tests on a base-isolated structure were carried out. Here, the base-isolation layer was taken as the tested part and tested in Kyoto University, Japan, and the superstructure was modelled by means of a ÿnite element program and analysed in a computer located in Osaka University. A series of physical Internet online tests were carried out, with the integration time interval and the method of tangent sti ness prediction as the major parameters. The tests demonstrated that the Internet communication was very stable and robust, without malfunctions. The proposed method of sti ness prediction was e ective even when the experimental hysteresis curves exhibited complex behaviour, thereby ensuring accurate simulation for the earthquake response of the entire structure.