Background: NQO2 protects against radiation-induced myeloproliferative disease, but the mechanism remains unknown. Results: Radiation-induced NQO2, independent of NQO1, competes with the 20 S proteasome for interactio...
详细信息
Background: NQO2 protects against radiation-induced myeloproliferative disease, but the mechanism remains unknown. Results: Radiation-induced NQO2, independent of NQO1, competes with the 20 S proteasome for interaction with c/EBP region Ser-268 to Val-279 to stabilize c/EBP, leading to protection against myeloproliferative disease. conclusion: NQO2 stabilizes c/EBP against 20 S degradation to protect against myeloproliferative disease. Significance: Stress-responsive NQO2 functions as an endogenous factor against myeloproliferative diseases. NRH:quinone oxidoreductase 2 (NQO2) is a flavoprotein that protects cells against radiation and chemical-induced oxidative stress. Disruption of the NQO2 gene in mice leads to radiation-induced myeloproliferative diseases. In this report, we showed that the 20 S proteasome and NQO2 both interact with myeloid differentiation factor ccAAT-enhancer-binding protein (c/EBP). The interaction of the 20 S proteasome with c/EBP led to the degradation of c/EBP. NQO2, in the presence of its cofactor NRH, protected c/EBP against 20 S degradation. Deletion and site-directed mutagenesis demonstrated that NQO2 and 20 S competed for the same binding region of S(268)GAGAGKAKKSV(279) in c/EBP. Exposure of mice and HL-60 cells to radiation enhanced the levels of NQO2, which led to an increased NQO2 interaction with c/EBP and decreased 20 S interaction with c/EBP. NQO2 stabilization of c/EBP was independent of NQO1, even though both interacted with the same c/EBP domain. NQO2(-/-) mice, deficient in NQO2, failed to stabilize c/EBP. This contributed to the development of radiation-induced myeloproliferative disease in NQO2(-/-) mice.
Aquatic humic substances from eight confined and unconfined aquifer/aquitard groundwater systems were analyzed for their stable carbon, radiocarbon, deuterium, and elemental contents. Fractionation of groundwater diss...
详细信息
Aquatic humic substances from eight confined and unconfined aquifer/aquitard groundwater systems were analyzed for their stable carbon, radiocarbon, deuterium, and elemental contents. Fractionation of groundwater dissolved organiccarbon (DOc) showed that humic substances are an important part of the organic solute load in all groundwaters. Groundwater humates are distinct from other terrestrial humates, and are characterized by low oxygen (36%) and high carbon (53%) contents. Elemental data from water table wells suggests this characteristic oxygen depletion is mainly a result of biochemical processes that occur in the vadose zone. The stable carbon isotopiccomposition of groundwater humates range between −31 and −24%. (PDB) with ann average of −26%., and reflect their terrestrial origins. The deuterium values of groundwater humate vary widely, and are mainly a reflection of 2 H/H variability in the continental water cycle. Radiocarbon analyses suggest a predominant soil zone origin for most groundwater humates, although some groundwater systems are influenced to varying degrees by buried peat or coal. Soluble humate 14 c mean residence times of up to several hundred years in the vadose zone before recharging to groundwater are due to the mixing of young and old organiccarbon sources, rather than advective residence times.
As research and implementation continue to facilitate high-performance computing in Java, applications can benefit from resource management and prediction tools. In this work, we present such a tool for network round-...
详细信息
As research and implementation continue to facilitate high-performance computing in Java, applications can benefit from resource management and prediction tools. In this work, we present such a tool for network round-trip time and bandwidth between a user's desktop and any machine running a Web server(not equal). JavaNws is a Java implementation and extension of a powerful subset of the Network Weather Service (NWS), a performance prediction toolkit that dynamically characterizes and forecasts the performance available to an application. However, due to the Java language implementation and functionality (portability, security, etc.), it is unclear whether a Java program is able to measure and predict the network performance experienced by c-applications with the same accuracy as an equivalent c program. We provide a quantitative equivalence study of the Java and c TcP-socket interface and show that the data collected by the JavaNws is as predictable as that collected by the NWS (using c), copyright (c) 2001 John Wiley & Sons, Ltd.
c is one of the most popular generally used languages of the 1980's. Its advantages are well known. In writing three books on the language, one of the authors has espoused many of its virtues without adequately co...
详细信息
c is one of the most popular generally used languages of the 1980's. Its advantages are well known. In writing three books on the language, one of the authors has espoused many of its virtues without adequately commenting on its vices. This paper will attempt to redress that balance.
In this study, the degradation performance of nutrients in zeolite trickling filter (ZTF) with different influent c/N ratios and aeration conditions was investigated. Microaeration was beneficial for enhancing NH4+-N ...
详细信息
In this study, the degradation performance of nutrients in zeolite trickling filter (ZTF) with different influent c/N ratios and aeration conditions was investigated. Microaeration was beneficial for enhancing NH4+-N removal performance. Due to the sufficient carbon source supply under a c/N ratio of 8, a high removal efficiency of NH4+-N and TN was simultaneously observed in ZTF. In addition, TN removal mainly occurred at the bottom, which might be explained by the sufficient nutrients available for bacteria to multiply in this zone. The abundant genera were Acinetobacter, Gemmobacter, Flavobacterium, and Pseudomonas, all of which are heterotrophic nitrification-aerobic denitrification (HNAD) bacteria. In addition, biofilm only slowed down the adsorption rate but did not significantly reduce the adsorption capacity of zeolite. Bio-zeolite had NH4+-N well adsorption capacity and bio-desorption capacity. Biological nitrogen removal performance was superior to physicochemical absorption of zeolite. The results suggested that the physicochemical of zeolite and biochemical reactions of microorganism coupling actions may be the main nitrogen transformation pathway in ZTF. Our research provides a reference for further understanding the nitrogen removal mechanism of zeolite bioreactors.
Small punch (SP) creep test specimen with an elliptical surface crack was suggested for use with creep crack growth testing. Estimation equations for fracture parameters are needed. K-equation was derived previously f...
详细信息
Small punch (SP) creep test specimen with an elliptical surface crack was suggested for use with creep crack growth testing. Estimation equations for fracture parameters are needed. K-equation was derived previously for the crack in the SP specimen. In this study, estimation equations for J and c* were derived. 3D elastic-plastic finite element analyses were carried out to determine J value along the front of the surface cracks of the same geometries as were employed for the K-estimation. The dimensionless function, h(1) was determined for various crack locations according to the EPRI scheme. The plastic limit load solution was also determined. The c*-equation of the cracked SP specimen was derived based on the J(p) solution using the analogy between the secondary creep constitutive law and the Ramberg-Osgood plasticity law. The c*-equation may be able to be used to characterize the creep crack growth behavior under the extensive creep condition of the cracked SP specimen.
In this study, c/c-Sic and c/c-Sic-Zrccomposites were prepared via chemical vapor infiltration and polymer infiltration pyrolysis, and the ablation mechanism under hypersonic oxygen-rich environmental conditions was ...
详细信息
In this study, c/c-Sic and c/c-Sic-Zrccomposites were prepared via chemical vapor infiltration and polymer infiltration pyrolysis, and the ablation mechanism under hypersonic oxygen-rich environmental conditions was investigated. The c/c-Siccomposites demonstrate an excellent ablation resistance in a hypersonic oxygen-rich environment with a relatively low temperature and speed of approximately 1800 K and 1100 m/s, respectively. It is only in the ablation center area with higher temperatures that a certain degree of thermochemical ablation was observed. The mass and linear ablation rates of c/c-Siccomposites (0.027 g/s and 0.117 mm/s, respectively) showed a significant increase in a hypersonic oxygen-rich environment with a temperature and velocity of approximately 2050 K and 2000 m/s, respectively. The high-temperature ablation resistance of Zrc-modified c/ c-Sic-Zrccomposites improved significantly. However, the Zrcceramiccomponent had a considerable impact on the ablation resistance of the material. The structural integrity of c/c-20Sic-30Zrccomposites was relatively high in hypersonic oxygen-rich environments with a jet temperature and velocity of 2050 K and 2000 m/s, respectively, and mass and linear ablation rates were 0.012 g/s and 0.015 mm/s, respectively. When the Zrccontent increased by 40%, the ablation resistance of the composite reduced significantly, whereas the mass and linear ablation rates increased to 0.043 g/s and 0.130 mm/s, respectively.
The effect of a seal device on the performance of aeroengines is obvious. As well as the complicated operating state of aeroengines also has important influence on seal device performance. Finger seal is a new seal de...
详细信息
The effect of a seal device on the performance of aeroengines is obvious. As well as the complicated operating state of aeroengines also has important influence on seal device performance. Finger seal is a new seal device, which has been extensively studied recently. However, so far there is little work about finger seal's dynamic performance considering work status. For this reason, finger seal's dynamic performance considering work status is proposed using equivalent dynamic model with distributed mass in this paper. The effects of the precession and nutation incline of rotor on the finger seal's performance are investigated. Meanwhile, density and preparation direction of fiber bundle have influence on its dynamic performance and that is studied under the rotor precession incline. Based on this, it is shown that the effect of rotor precession incline on the finger seal dynamic performance is obvious, thus it is necessary to consider the effect of the factor on finger seal dynamic performance. The present work is conducive to promote dynamic analysis technology of finger seal to engineering application, and also improve the theoretical research system and methodology of finger seal.
We report herein the exo-selective, regiospecific annulation of a wide range of functionalized aromatic substrates with 1,1-disubstituted alkenes through c(sp2)-H and benzylicc(sp3)-H activation by half-sandwich rare...
详细信息
We report herein the exo-selective, regiospecific annulation of a wide range of functionalized aromatic substrates with 1,1-disubstituted alkenes through c(sp2)-H and benzylicc(sp3)-H activation by half-sandwich rare-earth catalysts. This protocol offers a straightforward and atom-efficient route for the synthesis of a family of indane and tetralin derivatives bearing an all-carbon quaternary stereocenter that were difficult to access previously by other catalysts. The reaction mechanism has been elucidated by deuterium-labeling experiments and DFT calculations.
Aims The goal of this study was to examine, for the first time, the virulence and pathogenicity of aerosolized Burkholderia pseudomallei, strain NcTc 13392, in BALB/c mice in order to develop an animal model for testi...
详细信息
Aims The goal of this study was to examine, for the first time, the virulence and pathogenicity of aerosolized Burkholderia pseudomallei, strain NcTc 13392, in BALB/c mice in order to develop an animal model for testing novel medical countermeasures (McMs) for the treatment of human acute and subacute (a disease state between acute and chronic) melioidosis. Methods and Results BALB/c mice were exposed to varying doses of aerosolized bacteria. Acute disease was seen in animals exposed to a very-high dose (>= 10(3) cFU per animal) and death occurred 3-4 days postchallenge (pc). Bacteria were detected in the lungs, liver, kidney and spleen. In contrast, animals exposed to a low dose (<10 cFU per animal) survived to the end of the study (day 30 pc) but developed weight loss, a bacterial tissue burden and increasing clinical signs of infection from day 20 pc onwards, mimicking a subacute form of the disease. Pathological changes in the tissues mirrored these findings. conclusions This proof of concept study has shown that B. pseudomallei strain NcTc 13392 is virulent and pathogenic in BALB/c mice, when delivered by aerosol. By varying the doses of aerosolized bacteria it was possible to mimiccharacteristics of both human acute and subacute melioidosis, at the same time, within the same study. Significance and Impact of the Study Burkholderia pseudomallei, the aetiological agent of melioidosis, causes a serious and often fatal disease in humans and animals. Novel McMs are urgently needed for both public health and biodefense purposes. The present model provides a useful tool for the assessment and evaluation of new McMs (e.g. therapeutics and vaccines) and offers the potential for testing new treatments for both subacute to chronic and acute melioidosis prior to human clinical trials.
暂无评论