Main Progress of Microgravity Sciences and Space Life Sciences Research in China

The progress of the research activities on space material sciences, microgravity ‰uid physics and combustion, space life sciences and biotechnology research, fundamental Physics in China are brie‰y summarized in the present paper. The major space missions and experimental results obtained on board the Chinese recoverable/non-recoverable satellites and the Chinese manned spaceship named ``Shen-Zhou'' are presented summarily. The recent main activities of the ground-based studies in China are introduced in brief

Superconductivity in HfTe5 across weak to strong topological insulator transition induced via pressures

Recently, theoretical studies show that layered HfTe5 is at the boundary of weak & strong topological insulator (TI) and might crossover to a Dirac semimetal state by changing lattice parameters. The topological properties of 3D stacked HfTe5 are expected hence to be sensitive to pressures tuning. Here, we report pressure induced phase evolution in both electronic & crystal structures for HfTe5 with a culmination of pressure induced superconductivity. Our experiments indicated that the temperature for anomaly resistance peak (Tp) due to Lifshitz transition decreases first before climbs up to a maximum with pressure while the Tp minimum corresponds to the transition from a weak TI to strong TI. The HfTe5 crystal becomes superconductive above ~5.5 GPa where the Tp reaches maximum. The highest superconducting transition temperature (Tc) around 5 K was achieved at 20 GPa. Crystal structure studies indicate that HfTe5 transforms from a Cmcm phase across a monoclinic C2/m phase then to a P-1 phase with increasing pressure. Based on transport, structure studies a comprehensive phase diagram of HfTe5 is constructed as function of pressure. The work provides valuable experimental insights into the evolution on how to proceed from a weak TI precursor across a strong TI to superconductors

M2Net: Multi-modal Multi-channel Network for Overall Survival Time Prediction of Brain Tumor Patients

Early and accurate prediction of overall survival (OS) time can help to obtain better treatment planning for brain tumor patients. Although many OS time prediction methods have been developed and obtain promising results, there are still several issues. First, conventional prediction methods rely on radiomic features at the local lesion area of a magnetic resonance (MR) volume, which may not represent the full image or model complex tumor patterns. Second, different types of scanners (i.e., multi-modal data) are sensitive to different brain regions, which makes it challenging to effectively exploit the complementary information across multiple modalities and also preserve the modality-specific properties. Third, existing methods focus on prediction models, ignoring complex data-to-label relationships. To address the above issues, we propose an end-to-end OS time prediction model; namely, Multi-modal Multi-channel Network (M2Net). Specifically, we first project the 3D MR volume onto 2D images in different directions, which reduces computational costs, while preserving important information and enabling pre-trained models to be transferred from other tasks. Then, we use a modality-specific network to extract implicit and high-level features from different MR scans. A multi-modal shared network is built to fuse these features using a bilinear pooling model, exploiting their correlations to provide complementary information. Finally, we integrate the outputs from each modality-specific network and the multi-modal shared network to generate the final prediction result. Experimental results demonstrate the superiority of our M2Net model over other methods.Comment: Accepted by MICCAI'2

Control of the growth of human breast cancer cells in culture by manipulation of arachidonate metabolism

<p>Abstract</p> <p>Background</p> <p>Arachidonate metabolites are important regulators of human breast cancer cells. Production of bioactive lipids are frequently initiated by the enzyme phospholipase A2 which releases arachidonic acid (AA) that is rapidly metabolized by cyclooxygenases (COX) or lipoxygenases (LO) to other highly potent lipids.</p> <p>Methods</p> <p>In this study we screened a number of inhibitors which blocked specific pathways of AA metabolism for their antiproliferative activity on MCF-7 wild type and MCF-7 ADR drug resistant breast cancer cells. The toxicity of these inhibitors was further tested on human bone marrow cell proliferation.</p> <p>Results</p> <p>Inhibitors of LO pathways (specifically the 5-LO pathway) were most effective in blocking proliferation. Inhibitors of platelet activating factor, a byproduct of arachidonate release, were also effective antiproliferative agents. Curcumin, an inhibitor of both COX and LO pathways of eicosanoid metabolism, was 12-fold more effective in blocking proliferation of the MCF-7 ADR^scells compared to MCF-7 wild type (WT) cells. These inhibitors that effectively blocked the proliferation of breast cancer cells showed varying degrees of toxicity to cultures of human bone marrow cells. We observed greater toxicity to bone marrow cells with inhibitors that interfere with the utilization of AA in contrast to those which block utilization of its downstream metabolites. MK-591, MK-886, PCA-4248, and AA-861 blocked proliferation of breast cancer cells but showed no toxicity to bone marrow cells.</p> <p>Conclusion</p> <p>These inhibitors were effective in blocking the proliferation of breast cancer cells and may be potentially useful in human breast cancer therapy.</p

Distinct Genetic Diversity of Oncomelania hupensis, Intermediate Host of Schistosoma japonicum in Mainland China as Revealed by ITS Sequences

The intermediate host of Schistosoma japonicum in Asia is the snail Oncomelania hupensis, which can be separated phenotypically into ribbed- and smooth-shelled morphotypes. In China, the typical morphotype is ribbed-shelled, with its distribution restricted to mainland China. Smooth-shelled snails with varix are also distributed in China, which are considered to belong to the same subspecies as the ribbed-shelled snails. In this study we investigate the genetic variation among O. hupensis from different geographical origins using combined complete ITS1 and ITS2 regions of nuclear ribosomal DNA. Snails including ribbed-shelled and smooth-shelled (but with varix on the shell) from the lake/marshland region of the middle and lower reaches of the Yangtze River, and smooth-shelled snails from mountainous regions of Sichuan and Yunnan provinces, were genetically distinct with no shared haplotypes detected. Furtheremore, the snails from Sichuan and Yunnan provinces were clustered in separate clades in the phylogenetic tree, and three clades were observed for snails from the middle and lower reaches of the Yangtze River. The population diversity of O. hupensis in China is thus considered large, and evolutionary relationships in the host-parasite system of O. hupensis-S. japonicum may be of interest for further research

Diversification of Schistosoma japonicum in Mainland China Revealed by Mitochondrial DNA

Despite the existing threat of schistosomiasis in some rural areas along the Yangtze River, the genetic diversity of Schistosoma japonicum has not been investigated across its wide geographical distribution in China, and such information may provide insight into the disease epidemiology and the development of its control measures. In this study, the adult parasites, obtained through infecting mice with cercariae from snails of the genus Oncomelania collected from a wide range of localities in currently endemic areas of schistosomiasis in the middle and lower (ML) reaches of the Yangtze River, and in Sichuan and Yunnan provinces in the upper reaches of the river in southwest (SW) China, were sequenced individually for mitochondrial genes. In general, a relatively high degree of genetic variation was observed in populations in the ML reaches in terms of nucleotide and haplotype diversity, but a low level was observed in populations in the SW. The significant difference in genetic diversity as revealed by F-statistics, and the existence of no shared haplotypes, were observed between populations in the ML reaches and those in the SW, indicating the effect of geographical separation/isolation upon the schistosomes and probably the parasite-snail system in China

Promotion of prostatic metastatic migration towards human bone marrow stoma by Omega 6 and its inhibition by Omega 3 PUFAs

Epidemiological studies have shown not only a relationship between the intake of dietary lipids and an increased risk of developing metastatic prostate cancer, but also the type of lipid intake that influences the risk of metastatic prostate cancer. The Omega-6 poly-unsaturated fatty acid, Arachidonic acid, has been shown to enhance the proliferation of malignant prostate epithelial cells and increase the risk of advanced prostate cancer. However, its role in potentiating the migration of cancer cells is unknown. Here we show that arachidonic acid at concentrations ⩽5 μM is a potent stimulator of malignant epithelial cellular invasion, which is able to restore invasion toward hydrocortisone-deprived adipocyte-free human bone marrow stroma completely. This observed invasion is mediated by the arachidonic acid metabolite prostaglandin E2 and is inhibited by the Omega-3 poly-unsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid at a ratio of 1 : 2 Omega-3 : Omega-6, and by the COX-2 inhibitor NS-398. These results identify a mechanism by which arachidonic acid may potentiate the risk of metastatic migration and secondary implantation in vivo, a risk which can be reduced with the uptake of Omega-3 poly-unsaturated fatty acids

Lineage diversification and historical demography of a montane bird Garrulax elliotii - implications for the Pleistocene evolutionary history of the eastern Himalayas

<p>Abstract</p> <p>Background</p> <p>Pleistocene climate fluctuations have shaped the patterns of genetic diversity observed in many extant species. In montane habitats, species' ranges may have expanded and contracted along an altitudinal gradient in response to environmental fluctuations leading to alternating periods of genetic isolation and connectivity. Because species' responses to climate change are influenced by interactions between species-specific characteristics and local topography, diversification pattern differs between species and locations. The eastern Himalayas is one of the world's most prominent mountain ranges. Its complex topography and environmental heterogeneity present an ideal system in which to study how climatic changes during Pleistocene have influenced species distributions, genetic diversification, and demography. The Elliot's laughing thrush (<it>Garrulax elliotii</it>) is largely restricted to high-elevation shrublands in eastern Himalayas. We used mitochondrial DNA and microsatellites to investigate how genetic diversity in this species was affected by Pleistocene glaciations.</p> <p>Results</p> <p>Mitochondrial data detected two partially sympatric north-eastern and southern lineages. Microsatellite data, however, identified three distinct lineages congruent with the geographically separated southern, northern and eastern eco-subregions of the eastern Himalayas. Geographic breaks occur in steep mountains and deep valleys of the Kangding-Muli-Baoxin Divide. Divergence time estimates and coalescent simulations indicate that lineage diversification occurred on two different geographic and temporal scales; recent divergence, associated with geographic isolation into individual subregions, and historical divergence, associated with displacement into multiple refugia. Despite long-term isolation, genetic admixture among these subregional populations was observed, indicating historic periods of connectivity. The demographic history of <it>Garrulax elliotii </it>shows continuous population growth since late Pleistocene (about 0.125 mya).</p> <p>Conclusion</p> <p>While altitude-associated isolation is typical of many species in other montane regions, our results suggest that eco-subregions in the eastern Himalayas exhibiting island-like characteristics appear to have determined the diversification of <it>Garrulax elliotii</it>. During the Pleistocene, these populations became isolated on subregions during interglacial periods but were connected when these expanded to low altitude during cooler periods. The resultant genetic admixture of lineages might obscure pattern of genetic variation. Our results provide new insights into sky island diversification in a previously unstudied region, and further demonstrate that Pleistocene climatic changes can have profound effects on lineage diversification and demography in montane species.</p