猪链球菌2型可能的毒力基因的发现

猪链球菌 2型 (SS2 )感染已成为影响全世界养猪业的重要问题之一。SS2菌株可分为毒力株、弱毒力株和无毒力株 ,但目前尚无区分此 3类菌株的快速、有效的检测方法。为了获得毒力株特异的基因序列 ,对毒力株HA980 1及无毒力株 12 #进行了抑制性差减杂交 (SSH)实验 ,获得了 5个可能的新的毒力基因片段 ,分别是转录调节子、氨基酸通透酶、ABC转运子及表面锚定蛋白 ,在国内外尚属首次报道。这一发现将有助于区分SS2型菌株的毒力类型 ,并为SS2毒力株检测方法的建立奠定基础。

Effect of heat treatment on microstructure, mechanical properties and in vitro degradation behavior of as-extruded Mg-2.7Nd-0.2Zn-0.4Zr alloy

Mg-2.7Nd-0.2Zn-0.4Zr （mass fraction, %） alloy was designed for degradable biomedical material. The ingots of the alloy were solution treated and then hot extruded. The extruded rods were heat treated with aging treatment, solution treatment and solution＋aging treatment, respectively. Microstructures of the alloy were observed by optical microscopy （OM） and scanning electron microscopy （SEM）. Mechanical properties at room temperature were tested. In vitro degradation behavior of the alloy immersed in simulated body fluid was measured by hydrogen evolution and mass loss tests. The degradation morphologies of the alloy with and without degradation products were observed by SEM. The results show that the grains grow apparently after solution treatment. Solution treatment improves the elongation of as-extruded alloy significantly and decreases the strength, while aging treatment improves the strength and reduces the elongation of the alloy. The yield ratio is reduced by heat treatment. The in vitro degradation results of the alloy show that solution treatment on the as-extruded alloy results in a little higher degradation rate and aging treatment on the alloy can reduce degradation rate slightly.

Ecological Carrying Capacity in Beijing Mountainous Areas——Taking Fangshan District as an Example

[Objective] The aim was to investigate ecological carrying capacity of Fangshan District in Beijing. [Method] Ecological footprint and carrying capacity of Fangshan District in 2007 and 2008 were analyzed with ecological footprint model and the difference between ecological footprint and carrying capacity there was con- cluded. Furthermore, an assessment was made on relation between Fangshan de- velopment with local ecological carrying capacity to evaluate sustainable development of Fangshan District. [Result] Fangshan District is of lightly ecological deficit; ecologi- cal footprint per capita in 2007-2008 was deficit and tended to expand. Two meth- ods are available to reduce ecological ：deficit, including reduction of ecological foot- print and increase of carrying capacity. In general, supply and demand of carrying capacity in Fangshan are better, though with some problems. It is necessary to fur- ther develop related industries to final eliminate ecological deficit in order to achieve ecological conservation-orientation and sustainable development of Fangshan District. [Conclusion] The research provides theoretical references for overall evaluation on eco- logical carrying capacity of Fangshan District.

食醋美容

醋不仅可以灭菌治病,还可以养颜护肤。因此,不少人爱吃醋。比如,夏天吃凉拌菜时放些醋,能有效地预防肠道疾病;平时炒菜煮汤放些醋,能很好地预防感冒;将醋放入炒锅中熬或蒸,可以杀死屋内的细菌;坚持吃醋可以促进细胞的新陈代谢,增强对疾病的抵抗能力。 食醋不仅是一日三餐中不可缺少的一种调味品,而且在健肤美容方面也有其独到之处。相传古埃及王后克丽奥佩脱拉有一次与情人打贿。

Microstructure and properties of biodegradable β-TCP reinforced Mg-Zn-Zr composites

Magnesium alloys have good biocompatibility, but their mechanical properties and corrosion resistance may not be satisfied for using as degradable materials within bone due to its high corrosion rate in the physiological environment. Nano β-TCP particles were added into Mg-Zn-Zr alloy to improve its microstructure and the properties. As-extruded Mg-3Zn-0.8Zr alloy and Mg-3Zn-0.8Zr/xβ-TCP （x=0.5%, 1.0% and 1.5%） composites were respectively fabricated. The grains of Mg-Zn-Zr/β-TCP composites were significantly refined. The results of the tensile tests indicate that the ultimate tensile strength and the elongation of composites were improved with the addition of β-TCP. The electrochemical test result in simulation body fluid shows that the corrosion resistance of the composites was strongly enhanced comparing with that of the alloy. The corrosion potential of Mg-3Zn0.8-Zr/1.0β-TCP composite is 1.547 V and its corrosion current density is 1.20×10 6 A/cm 2 .

Microstructural investigation and castability anticipation in modern Ti/Al/Nb-containing nickel-based superalloys

A quantitative relation between the γ/γ′ and γ/Laves intermetallics was investigated with the change of chemical composition, i.e., Ti, Al and Nb in the third generation of nickel-based superalloys. The results demonstrated that the maximum amount of intermetallic eutectics （i.e., 41.5%, mass fraction） has been formed in 9.8% （Ti＋Al）. It is predicted that high level of intermetallics formed in the 3GSA-HNM-1 （γ-9.8%（Ti＋Al）） deteriorates its castability. The type and morphology of eutectic intermetallics change and the amount considerably diminishes by decreasing Ti＋Al in 3GSA-HNM-2 （γ-7.6%（Ti＋Al）, 1.5% Nb）. Thus, it is predicted that the castability for the 3GSA-HNM-2 improves. The amount of Laves intermetallics shows an ascending behavior again, however, with less intensity by increasing the Nb content in the 3GSA-HNM-3 （γ-5.7%（Ti＋Al）, 2.9% Nb）. It can be concluded that for 3GSA-HNM-3 with composition of γ-5.7%（Ti＋Al） and 2.9% Nb, the optimized castability can be anticipated, because the minimum amount of eutectic intermetallics （i.e., 4.7%） is formed.

Entrustable professional activities in nursing:A concept analysis

Objective:Entrustable professional activities(EPAs)is a newly emerging concept.This paper aims at analyzing the concept of"EPAs"to clarify the meaning and to identify its components for optimum understanding of the concept for use in nursing education and future research.Method:Three databases-ProQuest,Ovid,and PubMed-were retrieved,and Walker and Avant's concept analysis approach was used to analyze the concept of EPAs.Results:Based on the analysis,three attributes of EPAs were defined,namely (1)EPAs should be restricted to a limited number of tasks;(2)reflect the experience curve;and (3)include acceptance of responsibility and accountability.The antecedent of EPAs is a holistic and integrated assessment approach.This will eventually lead to anticipated consequences such as a mastery of core competencies and an increase in the level of autonomy.Conclusion:The study may contribute to a reduction in the ambiguity of this concept to better apply it in nursing practice.

Research Progress on Evaluation Frameworks of Regional Ecological Sustainability

As natural ecosystems provide the material basis and fundamental support for regional sustainable devel-opment,the sustainability of natural ecosystems is an important prerequisite and a viable approach for the achievement of regional sustainable development.It is also the final criteria to assess whether sustainable development paradigm is successful.Along with the increasing impacts of human activities on natural ecosystems,the evaluation of regional ecological sustainability has become one of the key issues for research on macro ecology and sustainable development.Based on different unit of indicators,this study firstly groups the evaluation frameworks of regional ecological sus-tainability into three major types:comprehensive index evaluation with dimensionless unit,monetary valuation,and biophysical quantity measurement.We then discuss and compare these types in terms of basic principles,scope of ap-plications,advantages and shortcomings.Finally,drawn on the discussion about characteristics of ecological sustain-ability,we outline the current trend and future directions of regional ecological sustainability evaluation,for instance,transition from sustainable development evaluation to sustainability science,integration of goal-oriented and problem-solving approaches,combination of spatial pattern analysis and ecological sustainability evaluation,and en-hancement of ecological sustainability evaluation at landscape scale.

Super-hydrophobic and super-lipophilic functionalized graphene oxide/polyurethane sponge applied for oil/water separation

Nowadays, oil spills have led to a serious environmental crisis of the world. To deal with this problem, inspired from super-hydrophobic lotus leaf, this study fabricated super-hydrophobic and super-lipophilic functionalized graphene oxide/polyurethane （FGP） sponge by a simple and inexpensive dip coating method. The resulting FGP sponge was characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy and water contact angle. The results expressed that FGP sponge exhibited a similar surface structure to that of a lotus leaf, and possessed the super-hydrophobic characteristic with the water contact angle （WAC） of 152°± 1 °. The absorption capacity and reusability were also investigated. It can be seen that, the FGP sponge can remove a wide range of oils and organic solvents from water with good absorption capacities （up to 35 times of its own mass）. Significantly, after 10 cycles the absorption capacity of the oils and organic solvents was higher than 90°; for the reused FGP sponge, demonstrating the good reusability of the FGP sponge. Therefore, this study probably provided a simole way to remove the pollutions ofoil spills and toxic organism from water.

Dynamics of the Coordination of Economy-Society and Resource-Environment in Shandong Peninsula,China

Shandong Peninsula,as a more developed region in Shandong Province even the east coast of China,is facing challenges from resources and environment pressures.This paper tried to track and assess the coordination status and the dynamic between resource-environment and economy-society systems in Shandong Peninsula during 2001-2008 in order to provide decision support for regional sustainability.An appraisal index system was built including five aspects of harmony degree(A),sustainability degree(B),opening degree(C),stability degree(D) and controllability degree(E).The results showed that:1) The coordination level of resource-environment and economy-society in Shandong Peninsula has continuously grown,and it has undergone three stages:no coordinated degree(2001-2002),weak coordinated degree(2003-2006) and basically coordinated degree(2007-2008).2) Five indexes of criterion hierarchy also increased overall,but each index showed different trends.Harmony degree,sustainability degree and opening degree rose all the time,while stability degree and controllability degree alternately rose and fell.The improvement of controllability degree was the slowest.3) The aggravating trend of environmental pollution was slowing down.The economic growth was driven by industrial growth and urbanization typically and investment was still the main force to pull the regional economic growth.At the same time,technology and education were becoming more and more important for economic growth.The level of foreign capital utility declined and the geographical advantage of Shandong Peninsula was exerted.Meanwhile some characteristics of knowledge economy were presenting.Water resources become the main constraint factor of fast development in Shandong Peninsula.It is necessary to further strengthen the coordination ability of government on regional sustainable development.

Modeling hot strip rolling process under framework of generalized additive model

This research develops a new mathematical modeling method by combining industrial big data and process mechanism analysis under the framework of generalized additive models(GAM)to generate a practical model with generalization and precision.Specifically,the proposed modeling method includes the following steps.Firstly,the influence factors are screened using mechanism knowledge and data-mining methods.Secondly,the unary GAM without interactions including cleaning the data,building the sub-models,and verifying the sub-models.Subsequently,the interactions between the various factors are explored,and the binary GAM with interactions is constructed.The relationships among the sub-models are analyzed,and the integrated model is built.Finally,based on the proposed modeling method,two prediction models of mechanical property and deformation resistance for hot-rolled strips are established.Industrial actual data verification demonstrates that the new models have good prediction precision,and the mean absolute percentage errors of tensile strength,yield strength and deformation resistance are 2.54%,3.34%and 6.53%,respectively.And experimental results suggest that the proposed method offers a new approach to industrial process modeling.

Peroral cholangioscopy in the new millennium

Peroral cholangioscopy was first described in 1970s and has recently gained popularity.Peroral cholangioscopy is appealing to therapeutic endoscopists because a direct intraluminal view of the biliary duct system offers possibilities for diagnosis and interventions beyond that which other imaging or endoscopic modalities can provide.As the image quality of cholangioscopies improves,so too does their diagnostic capability,and as their durability and maneuverability increases,so too does their potential use for therapeutic applications.This editorial is intended to provide a brief review of recent developments in peroral cholangioscopy and current indications for its use.

Numerical Investigations on the Aerodynamic Performance of Wind Turbine： Downwind Versus Upwind Configuration

Although the upwind configuration is more popular in the field of wind energy, the downwind one is a promising type for the offshore wind energy due to its special advantages. Different configurations have different aerodynamic performance and it is important to predict the performance of both downwind and upwind configurations accurately for designing and developing more reliable wind turbines. In this paper, a numerical investigation on the aerodynamic performance of National Renewable Energy Laboratory （NREL） phase V1 wind turbine in downwind and upwind configurations is presented. The open source toolbox OpenFOAM coupled with arbitrary mesh interface （AMI） method is applied to tackle rotating problems of wind turbines. Two 3D numerical models of NREL phase VI wind turbine with downwind and upwind configurations under four typical working conditions of incoming wind velocities are set up for the study of different unsteady characteristics of the downwind and upwind configurations, respectively. Numerical results of wake vortex structure, time histories of thrust, pressure distribution on the blade and limiting streamlines which can be used to identify points of separation in a 3D flow are presented. It can be concluded that thrust reduction due to blade-tower interaction is small for upwind wind turbines but relatively large for downwind wind turbines and attention should be paid to the vibration at a certain frequency induced by the cyclic reduction for both configurations. The results and conclusions are helpful to analyze the different aerodynamic performance of wind turbines between downwind and upwind configurations, providing useful references for practical design of wind turbine.

A robust tolerance design method based on process capability

This paper presents a method for robust tolerance design in terms of Process Capability Indices (PCI) . The component tolerance and the suitable manufacturing processes can be selected based on the real manufacturing context. The robustness of design feasibility under the effect of uncertainties is also discussed. A comparison between the results obtained by the proposed model and other methods indicates that robust and reliable tolerance can be obtained.

Analyze the service outsourcing on the base of the modern economy theory

The paper provides information about the concept and the characteristics of the service outsourcing. It also analyzes the service outsourcing classification and the modem economy theory of the service outsourcing. Through the analysis, we hope to provide the foundation for further study.

Super resolution reconstruction of moving objects from low resolution surveillance video

Construction of high resolution images from low resolution sequences having rigid or semi-rigid ob-jects with unified motions is often important in surveillance and other applications.In this paper a novelobject-based super resolution reconstruction scheme was proposed,in which a six-parameter affine model-based object tracking and registration method was first used to segment and match objects among a se-quence of low resolution frames.The motion model was then further extended to the traditional maximuma posterior(MAP)super resolution algorithm.The proposed object tracking and registration method wasevaluated by both simulated and real acquired sequences.The results have demonstrated the high accura-cy of the proposed object based method and the enhanced reconstruction performance of the extended ap-proach.

Jordanian Horticultural Export Competitiveness from Water Perspective

The main objective of this paper is to analyze the relationships between the productive process and the commercial trade with water resources used by them. For that the goal is to find out, by means of the estimation of water embodied in the exported crops which have the highest export competitiveness and lower water consumption. The finding contradicts not only the comparative advantages theory but also the resources sustainability logic. This conclusion is derived from the great exports of water via tomatoes and low profitable vegetables from producers＇ perspective but not economical from social perspectives as shown in domestic resource coefficient. The diversion between financial and economic profitability is due to heavily irrigation water subsidy. The results confirm that Jordan utilizes large amounts of water in its exports, and in turn, it does not export goods with low water requirements. The potential saving would be very significant and agricultural sector need to modify the use of water to a great extent in order to reach significant water savings and an environmental sustainability. Jordan has to implement policies that reduced, or even abandoned, the export and the production of water-intensive crops. Therefore, they have to be replaced with either imports or crops that optimize the water resources.

Why forefoot striking in minimal shoes might positively change the course of running injuries

It is believed that human ancestors evolved the ability to run bipedally approximately 2 million years ago. This form of locomotion may have been important to our survival and likely has influenced the evolution of our body form. As our bodies have adapted to run, it seems unusual that up to 79% of modern day runners are injured annually. The etiology of these injuries is clearly multifactorial. However, 1 aspect of running that has significantly changed over the past 50 years is the footwear we use. Modern running shoes have become increasingly cushioned and supportive, and have changed the way we run. In particular, they have altered our footstrike pattern from a predominantly forefoot strike(FFS) landing to a predominantly rearfoot strike(RFS) landing. This change alters the way in which the body is loaded and may be contributing to the high rate of injuries runners experience while engaged in an activity for which they were adapted. In this paper, we will examine the benefits of barefoot running(typically an FFS pattern),and compare the lower extremity mechanics between FFS and RFS. The implications of these mechanical differences, in terms of injury, will be discussed. We will then provide evidence to support our contention that FFS provides an optimal mechanical environment for specific foot and ankle structures, such as the heel pad, the plantar fascia, and the Achilles tendon. The importance of footwear will then be addressed, highlighting its interaction with strike pattern on mechanics. This analysis will underscore why footwear matters when assessing mechanics. Finally, proper preparation and safe transition to an FFS pattern in minimal shoes will be emphasized. Through the discussion of the current literature, we will develop a justification for returning to running in the way for which we were adapted to reduce running-related injuries.