Engineering topics
Liu, Su
Publications and source records attributed to Liu, Su.
SILAC Analysis Reveals Increased Secretion of Hemostasis-Related Factors by Senescent Cells
Cellular senescence irreversibly arrests cell proliferation, accompanied by a multi-component senescence-associated secretory phenotype (SASP) that participates in several age-related diseases. Using stable isotope labeling with amino acids (SILACs) and cultured cells, we identify 343 SASP proteins that senescent human fibroblasts secrete at 2-fold or higher levels compared with quiescent cell counterparts. Bioinformatic analysis reveals that 44 of these proteins participate in hemostasis, a process not previously linked with cellular senescence. We validated the expression of some of these SASP factors in cultured cells and in vivo. Mice treated with the chemotherapeutic agent doxorubicin, which induces widespread cellular senescence in vivo, show increased blood clotting. Conversely, selective removal of senescent cells using transgenic p16-3MR mice showed that clearing senescent cells attenuates the increased clotting caused by doxorubicin. Our study provides an in-depth, unbiased analysis of the SASP and unveils a function for cellular senescence in hemostasis.
Impacts of Instrument Limitations on Estimated Raindrop Size Distribution, Radar Parameters, and Model Microphysics during Mei-Yu Season in East China
Instrumentation limitations on measured raindrop size distributions (DSDs) and their derived relations and physical parameters are studied through a comparison of the DSD measurements during mei-yu season in east China by four collocated instruments, that is, a two-dimensional video disdrometer (2DVD), a vertically pointing Micro Rain Radar (MRR), and two laser-optical OTT Particle Size Velocity (PARSIVEL) disdrometers (first generation: OTT-1; second generation: OTT-2). Among the four instruments, the 2DVD provides the most accurate DSD and drop velocity measurements, so its measured rainfall amount has the best agreement with the reference rain gauge. Other instruments tend to miss more small drops ( D < 1 mm), leading to inaccurate DSDs and a lower rainfall amount. The low rainfall estimation becomes significant during heavy rainfall. The impacts of instrument limitations on the microphysical processes (e.g., evaporation and accretion rates) and convective storm morphology are evaluated. This is important especially for mei-yu precipitation, which is dominated by a high concentration of small drops. Furthermore, the instrument limitations need to be taken into account in both QPE and microphysics parameterization.
Advanced Testing Method for Ground Thermal Conductivity
A new method is developed that can quickly and more accurately determine the effective ground thermal conductivity (GTC) based on thermal response test (TRT) results. Ground thermal conductivity is an important parameter for sizing ground heat exchangers (GHEXs) used by geothermal heat pump systems. The conventional GTC test method usually requires a TRT for 48 hours with a very stable electric power supply throughout the entire test. In contrast, the new method reduces the required test time by 40%–60% or more, and it can determine GTC even with an unstable or intermittent power supply. Consequently, it can significantly reduce the cost of GTC testing and increase its use, which will enable optimal design of geothermal heat pump systems. Further, this new method provides more information about the thermal properties of the GHEX and the ground than previous techniques. It can verify the installation quality of GHEXs and has the potential, if developed, to characterize the heterogeneous thermal properties of the ground formation surrounding the GHEXs.
Dynamic Determination of Ground Thermal Conductivity and Minimum Thermal Response Test Duration Using the Line Source Mode
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