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Permafrost degradation may induce soil carbon (C) loss, critical for global C cycling, and be mediated by microbes. Despite larger C stored within the active layer of permafrost regions, which are more affected by warming, and the critical roles of Qinghai-Tibet Plateau in C cycling, most previous studies focused on the permafrost layer and in high-latitude areas. We demonstrate in situ that permafrost degradation alters the diversity and potentially decreases the stability of active layer microbial communities. These changes are associated with soil C loss and potentially a positive C feedback. This study provides insights into microbial-mediated mechanisms responsible for C loss within the active layer in degraded permafrost, aiding in the modeling of C emission under future scenarios., Competing Interests: The authors declare no competing interest.

Background: COVID-19 is novel infectious disease with an evolving understanding of its epidemiology and clinical manifestations. Severe cases developed life-threatening complications, such as respiratory failure, shock, and multiple organs dysfunction. Immunocompromised patients often present atypical presentations of viral infected diseases., Case Presentation: We report newly diagnosed HIV infections in two patients with COVID-19 in China. In our two cases, both patients with elevated IL-6 received Tocilizumab treatment, but did not present obvious therapeutic effect., Conclusions: These cases highlight possible co-detection of known immunocompromised diseases such as HIV. The two cases we reported stressed the risk of misdiagnosis, especially during the pandemic of an infectious disease and the importance of extended testing even if in immune-compromised condition the immune state may be ignored.

In order to study the mineral and elemental composition of insoluble microparticles (IP) in snow/ice, two snowpits were collected from the Zadang Glacier in Mt. Nyainqentanglha (30.47 degrees N, 90. 65 degrees E, 5 800 m a. s. l) in May and July, 2009, and IP samples were investigated. The measurements of mineral composition with different size fractions (d > 10 microm and 0.22 microm < d < 10 microm) were carried out using Particle-induced X-ray emission (PIXE) and X-ray diffraction analysis (XRD). The main mineral components of both coarse and fine IP are quartz, mica and calcite, accounting for 71.5% and 76.5%, respectively. The crustal elements concentrations (e.g. Si, Al, Fe, K, Mg and Ca) are 97% and 85.1% of total coarse/fine IP, while S, Cl and P take fairly proportion in fine microparticles (d < 10 microm). Seasonal variability of mineral composition in coarse microparticles (d >10 microm) is not obviously; However it's significantly in fine IP. Enrichment factors (EF) analysis reveals that several elements (e.g. Sc, P, Cr, S and Cl) in fine IP during monsoon season have high values which indicate these elements may be influenced by anthropogenic activities. Backward air mass trajectory analysis suggests that air masses in this region mainly originate from the South Asia areas during monsoon season, and air masses mainly come from arid/semi-arid region in the South and West Asia during non-monsoon season. Therefore, anthropogenic pollutants from the South Asia may be transported by the summer Indian monsoon to the Zadang glacier area. The coarse IP may derive from the local or remote mineral dust, and chemical compositions of fine IP interfere with anthropogenic pollutants.

To study the variations of microparticles and their origins, microparticles concentrations, stable oxygen isotope (delta18 O) and major ion concentrations were analyzed in snow samples collected from Mt. Geladaindong in the source region of Yangtze River. The correlation coefficents of different size microparticles in three snowpits are above 0.9 (significant at the 99% level), respectively. Microparticle concentrations have distinct seasonal variations, about 2-4 times higher in non-monsoon season than those in monsoon season, and are consistent with variations of delta18 O, Ca2+, Mg2+ and SO4(2-). Microparticle fluxes in non-monsoon season in three snowpits are 73.6%, 92.3% & 97% of total annual fluxes, respectively. Air mass backward trajectories over Mt. Geladaindong region were analyzed using the HYSPLIT&#95;4 model, and microparticles in Mt. Geladaindong snow were mostly influenced by dust aerosols from the northwestern Tibetan Plateau, South Asia. Coarse particles may come from the local rocks near glaciers. Research of seasonality of microparticle in snow could provide the information on modern environment processes, and is the base of further interpretation of ice core records.