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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.

Abstract Background One of the challenges of the analysis of pooling-based genome wide association studies is to identify authentic associations among potentially thousands of false positive associations. Results We present a hierarchical and modular approach to the analysis of genome wide genotype data that incorporates quality control, linkage disequilibrium, physical distance and gene ontology to identify authentic associations among those found by statistical association tests. The method is developed for the allelic association analysis of pooled DNA samples, but it can be easily generalized to the analysis of individually genotyped samples. We evaluate the approach using data sets from diverse genome wide association studies including fetal hemoglobin levels in sickle cell anemia and a sample of centenarians and show that the approach is highly reproducible and allows for discovery at different levels of synthesis. Conclusion Results from the integration of Bayesian tests and other machine learning techniques with linkage disequilibrium data suggest that we do not need to use too stringent thresholds to reduce the number of false positive associations. This method yields increased power even with relatively small samples. In fact, our evaluation shows that the method can reach almost 70% sensitivity with samples of only 100 subjects.

Utilizing the frequency selection characteristic of ring resonators, self-injection-locking linewidth narrowing and frequency stabilization of distributed feedback laser diodes (DFB-LDs) can be achieved under the aid of ring resonators. In this paper, the self-injection-locking effects of a DFB-LD realized by two fiber ring resonators and an optical waveguide ring resonator are compared. The influences of the resonant peak bandwidth and transmission on linewidth narrowing are demonstrated. It is shown that the mode hopping can be significantly suppressed by employing the optical waveguide ring resonator. This is of great significance for practical applications and integration of the self-injection-locked DFB-LDs. [ABSTRACT FROM AUTHOR]

Background: Patent foramen ovale (PFO) and obstructive sleep apnea (OSA) are independent risk factors for young conscious stroke which may also be concomitant symptoms with it. But there is no sufficient attention on these phenomena.Objective: To investigate the relationship between PFO, OSA and young stroke, and to look for proper treatment.Methods: Three patients with young conscious stroke were reported, each of them was combined with PFO and OSA. All patients were diagnosed as wake-up stroke (WUS). Contrast-enhanced transcranial doppler ultrasound (c-TCD) and polysomnography (PSG) test were used for auxiliary diagnosis.Results: Right-to-left shunts and moderate to severe sleep apnea were observed. Increased body mass index (BMI), hemoglobin (HGB) and hematocrit (HCT) index were also observed. After continuous positive airway pressure (CPAP) therapy, the number of microbubbles was reduced in one patient.Conclusions: These suggest that coexistence of PFO and OSA may associate with a greater risk of youth stroke. Decrease risk of stroke might occur if treating with CPAP in patients with OSA. [ABSTRACT FROM AUTHOR]

Abstract Huygens put forward his wave theory of light in as early as the 17th century, and he explained the process of light propagation with wavelet envelopes. So far, Huygens' principle has served as an explanation of the light propagation process and is mainly applied in the research of light diffraction. From the point of physics process, Huygens' principle transforms the process of light propagation into that of light radiation. We analyze the Huygens' principle from the wave equation. We find that its mathematical essence is the transformation among the different solutions of the wave equation. Built on the mathematical nature of the Huygens' principle, the direction, amplitude and phase of the Huygens wavelet were studied. Referring to the Poynting vector of electromagnetic waves, the tilt factor of the Huygens wavelet was obtained by vector analysis. Then according to the properties of plane waves and the Fresnel zone method and using the self-consistent principle, we lead to the conclusions that the phase of the Huygens wavelet is π/2 advanced of the incident light, and the wavelet amplitude is inversely proportional to the wavelength of the light. Finally, the relationship between wave optics and the primitive function is discussed. [ABSTRACT FROM AUTHOR]

We used Huygens’ principle to study the interaction between light and atom, and revealed the microcosmic process of the attenuation and gain of a plane wave. We began with the shadow of a leaf, expanding to the atomic absorption plane wave, and obtained the expression of the atomic absorption photon by using Huygens’ principle. Also the method of negative absorption is used to analyze the optical gain process, and we obtained the properties of a stimulated radiation photon according to the fact that the optical gain is atomic collective contribution of the stimulated radiation, the result shows that the atomic stimulated radiation is not photons cloning. [ABSTRACT FROM AUTHOR]

Abstract: The suitability of three different two-equation turbulence models in predicting film cooling effectiveness on a rotating blade was investigated and they are the commonly used standard k-ε model, the k-ω model and the shear stress transport k-ω model. To fulfill this target, both numerical simulation and the experimental investigation were carried out for a rotating blade having a flat test surface with a 4mm diameter straight circular cooling hole in 30° inclined injection. The blade rotated at five different speeds of 0, 300, 500, 800 and 1000rpm. The momentum ratio was set to be 0.285 and the Reynolds (Re D) number based on the mainstream velocity and hydraulic diameter of the mainstream channel is 1.45×105. The averaged density ratio was chosen to be 1.026 with air as both the coolant and the mainstream. Comparison between the numerical work and the experimental results indicated that (1) the rotating speed is the most critical parameter influencing the film cooling effectiveness distributions and the pressure surface could be remarkably different from the suction surface, (2) as for the algebraic averaged film cooling effectiveness, numerical predictions of the three turbulence models all overshoot compared with the experimental results, (3) among the three turbulence models, the standard k-ε model gave the poorest prediction. [Copyright &y& Elsevier]

In this study, we improve on current autoantigen discovery approaches by creating a synthetic representation of the complete human proteome, the T7 “peptidome” phage display library (T7-Pep), and use it to profile the autoantibody repertoires of individual patients. We provide methods for 1) designing and cloning large libraries of DNA microarray-derived oligonucleotides encoding peptides for display on bacteriophage, and 2) analysis of the peptide libraries using high throughput DNA sequencing. We applied phage immunoprecipitation sequencing (PhIP-Seq) to identify both known and novel autoantibodies contained in the spinal fluid of three patients with paraneoplastic neurological syndromes. We also show how our approach can be used more generally to identify peptide-protein interactions and point toward ways in which this technology will be further developed in the future. We envision that PhIP-Seq can become an important new tool in autoantibody analysis, as well as proteomic research in general.

Background: One of the challenges of the analysis of pooling-based genome wide association studies is to identify authentic associations among potentially thousands of false positive associations. Results: We present a hierarchical and modular approach to the analysis of genome wide genotype data that incorporates quality control, linkage disequilibrium, physical distance and gene ontology to identify authentic associations among those found by statistical association tests. The method is developed for the allelic association analysis of pooled DNA samples, but it can be easily generalized to the analysis of individually genotyped samples. We evaluate the approach using data sets from diverse genome wide association studies including fetal hemoglobin levels in sickle cell anemia and a sample of centenarians and show that the approach is highly reproducible and allows for discovery at different levels of synthesis. Conclusion: Results from the integration of Bayesian tests and other machine learning techniques with linkage disequilibrium data suggest that we do not need to use too stringent thresholds to reduce the number of false positive associations. This method yields increased power even with relatively small samples. In fact, our evaluation shows that the method can reach almost 70% sensitivity with samples of only 100 subjects.

Abstract The optical transfer function (OTF) can be used to evaluate the performance of optical imaging systems comprehensively and objectively. However, current method of determining an OTF is based on analyzing the imaging process in the spatial domain and combining the Fourier transform. For this issue, replacing optical rays by waves, we studied the lens imaging process of a cosine-fringe pattern and obtained the OTF of the lens without using the Fourier transform. First of all, we analyzed the properties of the light waves emitted from the cosine-fringe pattern. Then according to the lens' parameters and the use conditions, the quantity and quality of the coherent waves collected and utilized by the lens were analyzed, and the parameters of the cosine-fringe pattern on the image plane were obtained. Finally, the method of investigation of OTFs for ideal lens and aberrant lens without using Fourier transform was obtained. [ABSTRACT FROM AUTHOR]

Microwave guiding along double parallel lines of femtosecond-laser-generated plasma filament has been demonstrated over a distance of about 8 cm in air, corresponding to a maximum microwave signal intensity enhancement more than sixfold the free-space propagation. It is shown that the operating frequency and the line electric width influence the propagation coefficient of microwaves propagating along this transmission line. Based on channeling microwaves along this line and by measuring and comparing the propagated microwave signals, the basic parameters of laser-generated plasma filament, namely, its electron density and conductivity, are obtained. [ABSTRACT FROM AUTHOR]