Effect of Pore in Composition-B Explosive on Sensitivity under Impact of Drop Weight

Experiment impacting explosive sample with a drop weight is a standard approach in China. Pores in explosive have a significant effect on its sensitivity under impact of a drop weight. In the experiments impacting explosive samples with a drop weight, it is difficult to observe the dynamic responding and igniting process around a poreby using a measurement approach. This work developed an approach to predict the effect of pore in explosive onsensitivity under impact with drop weight. The effect of pore in composition-B explosive on the sensitivity under impact with a drop weight was investigated by using numeral simulation in this work. Through a series of numerica lcalculation, it was found that when the sizes of pore in composition-B explosive are less than 0.3 mm, its effect on sensitivity under impact of a drop weight can be ignored. This result agrees with the experimental data.Defence Science Journal, 2013, 63(1), pp.108-113, DOI:http://dx.doi.org/10.14429/dsj.63.232

Analysis on the aerodynamic performance of vertical axis wind turbine subjected to the change of wind velocity

AbstractReynolds averaged Navier-Stokes equations and Realizable kɛ− model were used in this paper, and the two dimensional unsteady flow field of the vertical axis wind turbine was simulated numerically at different wind velocity. The calculation results showed that the velocity in the region of wind turbine's rotation was much larger than the air flow of the upstream. The length of the wind turbine's downstream wake dispersion region was increased with the increase of the wind velocity. There is a much larger value of the eddy in the rear region of the wind turbine's rotational blades. And eddy existed in the downstream region of the wind turbine, and the larger velocity of cross flow, the larger value of the downstream flow's eddy. When the rotational speed was constant, with the increase in wind velocity, the variation of the wind turbine's total torque coefficient tended to smooth. The calculation results pointed out the direction for the follow-up study

Analysis on the influence of rotational speed to aerodynamic performance of vertical axis wind turbine

AbstractA two dimensional vertical axis wind turbine's model was established in this paper, and two dimensional unsteady incompressible N-S equations and Realizable kɛ− turbulence model were solved with software FLUENT. SIMPLC algorithm was applied, combined with the sliding grid technology; the influence of rotational speed to the flow structure of vertical axis wind turbine was discussed. The results showed that, the rotation of wind turbine had significant influence on wake, and higher the rotational speed, the greater reduction of the wake velocity. The wake velocity restored gradually away from the rotational part. There was much larger turbulent kinetic energy near the tail of the wind turbine's blade. The value of turbulent kinetic energy reduced gradually away from the rotational part, and the flow restored the stratospheric state gradually. With the increase of wind turbine's rotational speed, the value of turbulent kinetic energy in calculation domain increased too. The results showed that the flow structure of vertical axis wind turbine's rotational process could be revealed effectively by numerical simulation, provided theoretical reference for the engineering design of the vertical axis wind turbine

The analysis of contrast-enhanced ultrasound features of the liver in male patients with liver cancer and unhealthy life habits under 50 years-of-age

To analyze the contrast-enhanced ultrasound (CEUS) features of livers in male patients under 50 years-of-age with liver cancer and unhealthy life habits. A total of 89 male patients with liver cancer and unhealthy life habits were included in the observation group (all of these patients were first diagnosed with liver cancer when they were <50 years-of-age) and 60 male patients of the same age with benign liver lesions admitted during the same period were included in the control group. All patients had undergone CEUS examination. We summarized and compared the features of liver CEUS from patients in the two groups and analyzed the relationship between liver CEUS results and pathological features. The time to enhancement, enhancement duration and the clearance time of cancer tissues were all significantly shorter in patients from the observation group than those in the control group (p < 0.05). Enhancement patterns of cancer tissues and benign lesion tissues in patients in the observation group were significantly higher than those in the control group (p < 0.05). Cancerous tissues had fast wash-in and fast wash-out features (93.2%), while benign lesions had slow wash-in and slow wash-out features (60.00%). The proportion of patients with microvascular invasion (MVI)-positive lesions showing more than a 15% increase in maximum diameter was significantly larger than those with MVI-negative lesions (p < 0.05). The differences in enhancement features between liver cancer lesions with various differentiation grades in the portal phase and the delayed phase were statistically significant (p < 0.05). Our findings show that CEUS has high clinical value for diagnosing liver cancer and can be used to judge the MVI status and differentiation grade of liver cancer lesions, thus providing a reference for diagnosing liver cancer and its severity

Inducible and Selective Erasure of Memories in the Mouse Brain via Chemical-Genetic Manipulation

SummaryRapid and selective erasures of certain types of memories in the brain would be desirable under certain clinical circumstances. By employing an inducible and reversible chemical-genetic technique, we find that transient αCaMKII overexpression at the time of recall impairs the retrieval of both newly formed one-hour object recognition memory and fear memories, as well as 1-month-old fear memories. Systematic analyses suggest that excessive αCaMKII activity-induced recall deficits are not caused by disrupting the retrieval access to the stored information but are, rather, due to the active erasure of the stored memories. Further experiments show that the recall-induced erasure of fear memories is highly restricted to the memory being retrieved while leaving other memories intact. Therefore, our study reveals a molecular genetic paradigm through which a given memory, such as new or old fear memory, can be rapidly and specifically erased in a controlled and inducible manner in the brain

Lack of association between apolipoprotein C3 gene polymorphisms and risk of coronary heart disease in a Han population in East China

<p>Abstract</p> <p>Background</p> <p>Several polymorphisms in the apolipoprotein C3 (APOC3) gene have been found association with hypertriglyceridemia(HTG), but the link with coronary heart disease(CHD) risk between ethnicities was still controversial. Among them, reseachers paid more attentions to the promoter polymorphisms T-455C and C-482T because both of them located in insulin-responsive element (IRE) and insulin was thought to exert its action by down-regulating APOC3 gene expression. The aim of this study was to investigate the association of the two polymorphisms of APOC3 with CHD in a Han population in East China.</p> <p>Methods</p> <p>TaqMan SNP Genotyping Assays were carried out to detect the genotypes of APOC3 gene, including the T-455C and C-482T, in 286 subjects with CHD and 325 controls without CHD. The levels of serum lipid profiles were also detected by biochemical methods.</p> <p>Results</p> <p>There was no difference of genotype frequencies and allele frequencies between the CHD population and the controls(P > 0.05). Compared with the most common genotype -455TT or -482CC, the variants had neither significantly increased CHD risk, nor the lipid variables showed any statistically relevant differences in the research population. The adjusted OR of CHD were 5.67 [0.27-18.74] and 0.75 [0.20-2.73] in carriers of the APOC3 -455C and -482T variants, respectively(P > 0.05). There was also no significant difference in APOC3 haplotype distribution in CHD and controls, but there was a strong linkage disequilibrium between T-455C and C-482T with D' = 0.9293, 0.8881, respectively(P < 0.0001).</p> <p>Conclusions</p> <p>Our data did not support a relationship between the two polymorphisms of APOC3 gene and risk of CHD in the Han population in East China.</p

Increase in grain production potential of China under climate change

The rapid growth of China’s demand for grains is expected to continue in the coming decades, largely as a result of the increasing feed demand to produce protein-rich food. This leads to a great concern on future supply potentials of Chinese agriculture under climate change and the extent of China’s dependence on world food markets. While the existing literature in both agronomy and climate economics indicates a dominance of the adverse impacts of climate change on rice, wheat, and maize yields, there is a lack of study to assess changes in multi-cropping opportunities induced by climate change. Multi-cropping benefits crop production by harvesting more than once per year from a given plot. To address this important gap, we established a procedure within the Agro-ecological Zones (AEZ) modeling framework to assess future spatial shifts of multi-cropping conditions. The assessment was based on an ensemble of five General Circulation Models under four Representative Concentration Pathway scenarios in the Phase Five of Coupled Model Inter-comparison Project and accounted for the water scarcity constraints. The results show significant northward extensions of single-, double- and triple-cropping zones in the future which would provide good opportunities for crop-rotation based adaptation. The increasing multi-cropping opportunities would be able to boost the annual grain production potential by an average scale of 89(±49) Mt at the current irrigation efficiency and 143(±46) Mt at the modernized irrigation efficiency with improvement between the baseline (1981-2010) and the mid-21st century (2041-2070)

The Ambiguous Relationship of Oxidative Stress, Tau Hyperphosphorylation, and Autophagy Dysfunction in Alzheimer’s Disease

Alzheimer’s disease (AD) is the most common form of dementia. The pathological hallmarks of AD are amyloid plaques [aggregates of amyloid-beta (Aβ)] and neurofibrillary tangles (aggregates of tau). Growing evidence suggests that tau accumulation is pathologically more relevant to the development of neurodegeneration and cognitive decline in AD patients than Aβ plaques. Oxidative stress is a prominent early event in the pathogenesis of AD and is therefore believed to contribute to tau hyperphosphorylation. Several studies have shown that the autophagic pathway in neurons is important under physiological and pathological conditions. Therefore, this pathway plays a crucial role for the degradation of endogenous soluble tau. However, the relationship between oxidative stress, tau protein hyperphosphorylation, autophagy dysregulation, and neuronal cell death in AD remains unclear. Here, we review the latest progress in AD, with a special emphasis on oxidative stress, tau hyperphosphorylation, and autophagy. We also discuss the relationship of these three factors in AD