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For the purpose of dissipating large heat power with cyclical operating modes of satellite, one mechanically pumped two-phase loop (MPTL) coupled with a novel phase change energy storage device was designed and constructed. The phase change energy storage device integrating with filament tube heat exchanger and form-stable phase change material (PCM) with expanded graphite (EG) was designed and employed to increase the conductivity. The two-phase change behavior of liquid-vapor change for MPTL and solid-liquid transition for PCM was used to acquire, transport and store the heat. Results indicated that the time of heat storage for PCM device was more than 598.0 s, and the temperature at the outlet of the device increased from −2.0 °C to 15.0 °C under the heating power of 6.7 kW. The flowrate decreased from 0.059 kg/s to 0.034 kg/s due to the length increase of two-phase section during the melting process of PCM device. Lowering the rotation speed of pump increased the oscillating amplitude of flowrate, and its maximum value reached to 0.008 kg/s. The total working period for PCM device for lower rotation speed of 8000 r/min was 48.0 s longer than that for higher speed of 10000 r/min due to decreased heat transfer coefficient. [ABSTRACT FROM AUTHOR]

Mechanically pumped two-phase loop (MPTL) is an advanced two-phase heat transfer device through the release of latent heat of phase change during flow boiling process. In order to investigate the performance of MPTL system under different gravity conditions, one MPTL setup using a novel two-phase thermal-controlled accumulator coupled with self-cooling function was designed and constructed. Its characteristics of startup, phase change, and temperature control were tested on the ground and on orbit. Test results showed that MPTL system had good working performance and stable working characteristics both on the ground and on a satellite. The functions of fluid management, temperature control and self-cooling for accumulator were verified under different gravity conditions. It was found that the superheat time and superheat temperature for on-orbit results were longer and higher than the ground's results respectively. The heat transfer efficient of two-phase flow of MPTL system could reach 12,000 − 60,000 W/(m2·K). Affected by the buoyancy, the heat transfer coefficient on-orbit was 10%−29% lower than the ground result. The research would contribute to the theoretical basis of two-phase flow and heat transfer and promote the development of active two-phase thermal control technology for space. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau is an important area for studying global climate change, but the answers to many scientific problems remain unknown. Here, we present new information from the lacustrine sedimentary record in the western Tibetan Plateau, related to the third most‐recent glaciations. Continuous sediment data, including sporopollen, particle size, total organic carbon, mass susceptibility, CaCO3, CaSO4, BaSO4 contents and chronological data, were reconstructed and revealed that climate and environmental conditions obviously and distinctly changed between 600 and 700 thousand years ago. In comparison, the data obtained from the Guliya ice core in this area also corresponds to the global glacial climatic characteristics recorded in basin sediments in the eastern and southeastern regions of the plateau and to the information obtained from ice cores in the Antarctic and Arctic regions. In this study, we conclude that the main reason for the glaciations and new tectonic movement must be a geomagnetic polarity reversal 774 thousand years ago (from Matuyama to Brunhes). Indeed, the results of this study suggest that the described reversal event might have influenced the current global climate pattern and will continue to impact climatic changes in the future. [ABSTRACT FROM AUTHOR]

The two-hybrid protein screen, DivIVa and FtsZ, can be used to target green fluorescent proteins to cell division sites in both Escherichia coli and Agrobacteium tumefaciens. Data suggest that such cell-location specific two-hybrid screens are useful to study interaction among cytosolic and membrane proteins in bacteria.

Research discusses the role of virE1 gene and its encoded product VirE1 secretion chaperone in mediating multifunctional effector protein VirE2 export via type IV secretion system in Agrobacterium tumefaciens. Data indicate that virE1 regulates virE2 translation, VirE1 protein stabilizes VirE2, and VirE1 forms a VirE1-VirE2 complex.

Abstract Background Imputation of missing genotypes is becoming a very popular solution for synchronizing genotype data collected with different microarray platforms but the effect of ethnic background, subject ascertainment, and amount of missing data on the accuracy of imputation are not well understood. Results We evaluated the accuracy of the program IMPUTE to generate the genotype data of partially or fully untyped single nucleotide polymorphisms (SNPs). The program uses a model-based approach to imputation that reconstructs the genotype distribution given a set of referent haplotypes and the observed data, and uses this distribution to compute the marginal probability of each missing genotype for each individual subject that is used to impute the missing data. We assembled genome-wide data from five different studies and three different ethnic groups comprising Caucasians, African Americans and Asians. We randomly removed genotype data and then compared the observed genotypes with those generated by IMPUTE. Our analysis shows 97% median accuracy in Caucasian subjects when less than 10% of the SNPs are untyped and missing genotypes are accepted regardless of their posterior probability. The median accuracy increases to 99% when we require 0.95 minimum posterior probability for an imputed genotype to be acceptable. The accuracy decreases to 86% or 94% when subjects are African Americans or Asians. We propose a strategy to improve the accuracy by leveraging the level of admixture in African Americans. Conclusion Our analysis suggests that IMPUTE is very accurate in samples of Caucasians origin, it is slightly less accurate in samples of Asians background, but substantially less accurate in samples of admixed background such as African Americans. Sample size and ascertainment do not seem to affect the accuracy of imputation.