Experimental Study on the Ethanol-Assisted Catalytic Steam Reforming of Endothermic Hydrocarbon Fuel.

Thermal protection is a critical problem in the development of hypersonic aircraft. To enhance the thermal protection capability of hydrocarbon fuel, the ethanol-assisted catalytic steam reforming of endothermic hydrocarbon fuel was proposed. The result shows that the total heat sink can be significantly improved by the endothermic reactions of ethanol. A higher water/ethanol ratio can promote the steam reforming of ethanol and further increase the chemical heat sink. The addition of 10 wt % ethanol at 30 wt % water content can improve the total heat sink by 8-17% at 300-550 °C, which is caused by the heat absorption by phase transition and chemical reactions of ethanol. The reaction region of thermal cracking moves backward, resulting in the suppression of thermal cracking. Meanwhile, the addition of ethanol can inhibit the coke deposition and increase the working temperature upper limit of the active thermal protection.

Secondary Flow Effect on Supercritical Kerosene Oxidation Deposition and Heat Transfer in a Coiled Tube.

Deposition in fuel cooling systems remains a challenge to the development of active cooling technologies for air-breathing engines. We experimentally and numerically investigated the influence of the secondary flow and heat-transfer characteristics of supercritical kerosene in a coiled tube on oxidation deposition. A coiled heated tube reactor (3000 mm long, 23 cycles) under constant heat flux and flow rate was applied to simulate the conditions of the fuel side in the heat exchanger of an aero-engine cooling system. The coupling characteristics of coking distribution with the development of secondary flow were studied along the whole pipe. The dynamic pressure, temperature, and velocity were analyzed in two specific circular cross sections located in the bend of the tube. The secondary flows induced in the coiled tube greatly enhance the heat transfer and slightly decrease the deposition rate, resulting in linear wall temperature profiles and a uniform coking distribution along the tube compared to the long straight tube. There is no obvious heat-transfer enhancement or deterioration in the whole coiled tube. The modified heat-transfer correlation of the supercritical RP-3 in the coiled tube was fitted at different flow rates and heat fluxes with an error of ±10%.

Ancient Mitogenomes Reveal the Domestication and Distribution of Cattle During the Longshan Culture Period in North China.

Cattle, as an important tool for agricultural production in ancient China, have a complex history of domestication and distribution in China. Although it is generally accepted that ancient Chinese taurine cattle originated from the Near East, the explanation regarding their spread through China and whether or not this spread was associated with native aurochs during ancient times are still unclear. In this study, we obtained three nearly complete mitochondrial genomes (mitogenomes) from bovine remains dating back ca. 4,000 years at the Taosi and Guchengzhai sites in North China. For the first time at the mitogenome level, phylogenetic analyses confirmed the approximately 4,000-year-old bovines from North China as taurine cattle. All ancient cattle from both sites belonged to the T3 haplogroup, suggesting their origin from the Near East. The high affinity between ancient samples and southern Chinese taurine cattle indicated that ancient Chinese cattle had a genetic contribution to the taurine cattle of South China. A rapid decrease in the female effective population size ca. 4.65 thousand years ago (kya) and a steep increase ca. 1.99 kya occurred in Chinese taurine cattle. Overall, these results provide increasing evidence of the origin of cattle in the middle Yellow River region of China.

IRF4 and STAT3 activities are associated with the imbalanced differentiation of T-cells in responses to inhalable particulate matters.

BACKGROUND: Particulate Matter (PM) is known to cause inflammatory responses in human. Although prior studies verified the immunogenicity of PM in cell lines and animal models, the effectors of PM exposure in the respiratory system and the regulators of the immunogenicity of PM is not fully elucidated. METHODS: To identify the potential effector of PM exposure in human respiratory system and to better understand the biology of the immunogenicity of PM, We performed gene-expression profiling of peripheral blood mononuclear cells from 171 heathy subjects in northern China to identify co-expressed gene modules associated with PM exposure. We inferred transcription factors regulating the co-expression and validated the association to T-cell differentiation in both primary T-cells and mice treated with PM. RESULTS: We report two transcription factors, IRF4 and STAT3, as regulators of the gene expression in response to PM exposure in human. We confirmed that the activation of IRF4 and STAT3 by PM is strongly associated with imbalanced differentiation of T-cells in the respiratory tracts in a time-sensitive manner in mouse. We also verified the consequential inflammatory responses of the PM exposure. Moreover, we show that the protein levels of phosphorylated IRF4 and STAT3 increase with PM exposure. CONCLUSIONS: Our study suggests the regulatory activities of IRF4 and STAT3 are associated with the Th17-mediated inflammatory responses to PM exposure in the respiratory tracts, which informs the biological background of the immunogenicity of particulate matters.

Genome-wide analysis of the callose enzyme families of fertile and sterile flower buds of the Chinese cabbage (Brassica rapa L. ssp. pekinensis).

Callose is a ß-1,3-glucan commonly found in higher plants that plays an important role in regulating plant pollen development. It is synthesized by glucan synthase-like (GSL) and is degraded by the enzyme endo-1,3-ß-glucosidase. However, genome-wide analyses of callose GSL and endo-1,3-ß-glucosidase enzymes in fertile and sterile flower buds of Chinese cabbage have not yet been reported. Here, we show that delayed callose degradation at the tetrad stage may be the main cause of microspore abortion in Chinese cabbage with nuclear sterility near-isogenic line '10L03'. Fifteen callose GSLs and 77 endo-1,3-ß-glucosidase enzymes were identified in Chinese cabbage. Phylogenetic, gene structural and chromosomal analyses revealed that the expansion occurred due to three polyploidization events of these two gene families. Expression pattern analysis showed that the GSL and endo-1,3-ß-glucosidase enzymes are involved in the development of various tissues and that the genes functionally diverged during long-term evolution. Relative gene expression analysis of Chinese cabbage flowers at different developmental stages showed that high expression of the synthetic enzyme BraA01g041620 and low expression of AtA6-homologous genes (BraA04g008040, BraA07g009320, BraA01g030220 and BraA03g040850) and two other genes (BraA10g020080 and BraA05g038340) for degrading enzymes in the meiosis and tetrad stages may cause nuclear sterility in the near-isogenic line '10L03'. Overall, our data provide an important foundation for comprehending the potential roles of the callose GSL and endo-1,3-ß-glucosidase enzymes in regulating pollen development in Chinese cabbage.

Effects of particulate matter on allergic respiratory diseases.

The health impact of airborne particulate matter (PM) has long been a concern to clinicians, biologists, and the general public. With many epidemiological studies confirming the association of PM with allergic respiratory diseases, an increasing number of follow-up empirical studies are being conducted to investigate the mechanisms underlying the toxic effects of PM on asthma and allergic rhinitis. In this review, we have briefly introduced the characteristics of PM and discussed its effects on public health. Subsequently, we have focused on recent studies to elucidate the association between PM and the allergic symptoms of human respiratory diseases. Specifically, we have discussed the mechanism of action of PM in allergic respiratory diseases according to different subtypes: coarse PM (PM2.5-10), fine PM (PM2.5), and ultrafine PM.

Germline and somatic variations influence the somatic mutational signatures of esophageal squamous cell carcinomas in a Chinese population.

BACKGROUND: Esophageal squamous cell carcinomas (ESCC) is the fourth most lethal cancer in China. Previous studies reveal several highly conserved mutational processes in ESCC. However, it remains unclear what are the true regulators of the mutational processes. RESULTS: We analyzed the somatic mutational signatures in 302 paired whole-exome sequencing data of ESCC in a Chinese population for potential regulators of the mutational processes. We identified three conserved subtypes based on the mutational signatures with significantly different clinical outcomes. Our results show that patients of different subpopulations of Chinese differ significantly in the activity of the "NpCpG" signature (FDR = 0.00188). In addition, we report ZNF750 and CDC27, of which the somatic statuses and the genetic burdens consistently influence the activities of specific mutational signatures in ESCC: the somatic ZNF750 status is associated with the AID/APOBEC-related mutational process (FDR = 0.0637); the somatic CDC27 copy-number is associated with the "NpCpG" (FDR = 0.00615) and the AID/APOBEC-related mutational processes (FDR = 8.69 × 10- 4). The burdens of germline variants in the two genes also significantly influence the activities of the same somatic mutational signatures (FDR < 0.1). CONCLUSIONS: We report multiple factors that influence the mutational processes in ESCC including: the subpopulations of Chinese; the germline and somatic statuses of ZNF750 and CDC27 and exposure to alcohol and tobacco. Our findings based on the evidences from both germline and somatic levels reveal potential genetic regulators of the somatic mutational processes and provide insights into the biology of esophageal carcinogenesis.

Experimental study of a low-thrust measurement system for thruster ground tests.

The development of thrusters used for the control of position and orbit of micro-satellites requires thrust stands that can measure low thrust. A new method to measure low thrust is presented, and the measuring device is described. The test results show that the thrust range is up to 1000 mN, the measurement error of the device is lower than ±1% of full scale, and the drift of the zero offset is less than ±1% of full scale. Its response rise time is less than 15 ms. It is employed to measure the working process of a model chemical thruster with repeatability.

[Experimental study on spectra of compressed air microwave plasma].

Using a microwave plasma generator, compressed air microwave plasma was excited under 1 - 5 atm pressures. Under different pressures and different incident microwave power, the emission spectra of compressed air microwave plasma were studied with a spectra measuring system. The results show that continuum is significant at atmospheric pressure and the characteristic will be weakened as the pressure increases. The band spectra intensity will be reduced with the falling of the incident microwave power and the band spectra were still significant. The experimental results are valuable to studying the characteristics of compressed air microwave plasma and the generating conditions of NO active groups.

[Spectrum diagnosis of enhanced arcjet thruster using hydrazine propellant].

A set of spectrum diagnostic system was established. With this system, spectrum analysis was carried out for the plume signal of enhanced arcjet thrust using catalytic decomposition products of hydrazine as propellant. Excitation plume temperatures for various wavelengths were obtained through measuring spectral radiation intensity. The averaged excitation temperatures were analyzed based on Boltzman diagram. The results show that there is the highest temperature in the axial center of plume and the temperature drops quickly in the radial direction. The intensity of thermodynamic non-equilibrium weakens with a decrease in current and an increase in radial distance. The temperature of the plume rises with an increase in the proportion of ammonia in the catalytic decomposition mixture of hydrazine.

[Physical meaning of temperature measured by spectral line intensity method].

The difference between electron temperature and excitation temperature is analyzed in the aspect of statistics thermodynamics. It is presented clearly that the temperature acquired by spectral line intensity method is not free electron temperature, but internal electronic excitation temperature of heavy particle. Under thermal equilibrium condition, the excitation temperature is equal to the electron temperature, while under non-thermal equilibrium condition, the excitation temperature is not equal to the electron temperature. In the study of arc jet plume in vacuum chamber, spectral line intensity method was employed to measure the apparent excitation temperature of arc jet plume, and Langmuir probe was employed to measure the electron temperature of arcjet plume. The big difference between the excitation temperature and the electron temperature proved that the temperature acquired by spectral line intensity method is not free electron temperature.