Isolation and characterization of H7N9 viruses from live poultry markets--Implication of the source of current H7N9 infection in humans

On March 31, 2013, the National Health and Family Planning Commission announced that human infections with a previously undescribed influenza A (H7N9) virus had occurred in Shanghai and Anhui Province, China. To investigate the possible origins of the H7N9 viruses causing these human infections, we collected 970 samples, including drinking water, soil, and cloacal and tracheal swabs of poultry from live poultry markets and poultry farms in Shanghai and Anhui Province. Twenty samples were positive for the H7N9 influenza virus. Notably, all 20 viruses were isolated from samples collected from live poultry markets in Shanghai. Phylogenetic analyses showed that the six internal genes of these novel human H7N9 viruses were derived from avian H9N2 viruses, but the ancestor of their HA and NA genes is uncertain. When we examined the phylogenetic relationship between the H7N9 isolates from live poultry markets and the viruses that caused the human infections, we found that they shared high homology across all eight gene segments. We thus identified the direct avian origin of the H7N9 influenza viruses that caused the human infections. Importantly, we observed that the H7N9 viruses isolated from humans had acquired critical mutations that made them more "human-like". It is therefore imperative to take strong measures to control the spread of H7N9 viruses in birds and humans to prevent further threats to human health.     

Reconstruction results about the exponential radon transform

In this paper, the properties of the exponential Radon transform and its dual are discussed. Furthermore, the analytical reconstruction formulas of exponential Radon transform with two different methods are developed.     

The mobilization of rat’s mesenchymal stem cells into peripheral blood by LiCL and its potency differentiation

Mesenchymal stem cells （MSCs） are multipotent cells, which can differentiate into different tissues. It is still controversial whether MSCs can be isolated from adult peripheral blood （PB） under normal conditions and whether they can be mobilized in a way similar to that of hematopoieUc stem cells （HSCs）. In this study, rat MSCs circulating in the PB under normal conditions can be isolated and cultured, and MSCs from PB and BM can be mobilized by LiCL. The mobilized MSCs can be induced to differentiate into neuron by such factors as β-mercaptoethanol and supernatants of nerve cell cultures. The present study provides a broader perspective on the repair of neural trauma.     

Heat treatment of novel low-carbon multi-alloyed anti-wear marine steel

A low-carbon anti-wear steel,multi-alloyed with Si-Cr-Mn-Al-Ni-Mo-(Nb,RE),was designed for vane pumps of ships. The novel cast steel after various heat treatments was characterized by microstructure observations and mechanical properties measurement in order to achieve an optimal process correlated with good abrasive resistance for a long marine service.Differential scanning calorimetry and hardness analyses deduced a complete austenitizing temperature of 1 000℃,based on the alloying element homogenizati...     

Status in quo and future of geothermal energy in China

Energy saving and CO2 emissions reduction are critical tasks currently,and great effort has been made by Chinese government. Renewable energy consumption and CO2 emissions and reduction plan in China are introduced in this paper. Analysis is also made on present status and prospect of geothermal power generation and direct use in China respectively. Now,there is a new understanding of geothermal resources,and hot dry rock,considered as the future of geothermal resources,is likely used to generate electricity.     

Effect of vanadium carbide on commercial pure aluminum

The effect of vanadium carbide (VC) on the grain size of commercial pure aluminum was experimentally investigated by varying the content of VC, the holding time, and casting temperature. The refining efficiencies of VC and Al5Ti1B were also compared. The refined samples of commercial pure aluminum were examined using optical microscopy, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The results suggest that VC is a good refiner of commercial pure aluminum. The addition of only 0.3wt% VC can decrease the grain size of aluminum to 102 μm, whereas the casting temperature and holding time have little effect on the grain size. The refining efficiency of VC is better than that of Al5Ti1B. The VC particles in molten aluminum act as nuclei and the grain refinement of aluminum alloys by VC particles is achieved via heterogeneous nucleation.     

3-PRS serial-parallel machine tool error calibration and parameter identification

3PRS serialparallel machine tool consists of a 3degreeoffreedom (DOF) implementation platform and a 2DOF XY platform. The error modeling and parameter identification methods were deduced based on 3PRS serialparallel machine tool. 3PRS serialparallel machine tool was researched, 〖JP2〗and the mechanism of error analysis, modeling, identification of error parameters and measurement equipment for the use of agency error of measurement were conducted. In order to achieve the geometric parameters calibration and error compensation of the serialparallel machine tool, the nominal structural parameters of the controller was adjusted by identifying the structure of the machine tool. With the establishment of a vector space size chain, we can do the error analysis, error modeling, error measurement and error compensation can be done.     

生物柴油高效合成方法研究

采用连续流动式、碱催化和超声辅助强化等手段,研究了一种新的生物柴油合成方法.优化了温度、催化荆用量和反应时间等影响酯交换反应的因素.采用核磁共振(NMR)分析方法,研究了在不同反应条件下的酯交换率.结果表明,当流动式反应盘管长为130 cm,甲醇与大豆油以9:1的摩尔比混合,反应温度为40℃,反应时间为13 min,NaOH用量在油重的0.5%的实验条件下酯交换率可达到99.9%以上.     

显微组织对无限冷硬铸铁轧辊热疲劳性能的影响

文章介绍在无限冷硬铸铁轧辊上切取板状热疲劳试样,在自制的热疲劳试验机上进行了冷热循环实验,研究了显微组织对无限冷硬铸铁热疲劳裂纹萌生及扩展的影响.结果表明,热疲劳裂纹在石墨尖端处、珠光体基体及共晶碳化物中萌生;热疲劳裂纹主要在钢基体与共晶莱氏体界面处、钢基体内扩展及穿越共晶碳化物.     

浅谈电力系统电压稳定性

介绍了电力系统电压稳定的定义和分类,提出了电压失稳机理和电压稳定的主要研究方法,反映出该领域的研究概貌和最新动向.