The building blocks of planets within the 'terrestrial' region of protoplanetary disks

Our Solar System was formed from a cloud of gas and dust. Most of the dust mass is contained in amorphous silicates, yet crystalline silicates are abundant throughout the Solar System, reflecting the thermal and chemical alteration of solids during planet formation. (Even primitive bodies such as comets contain crystalline silicates.) Little is known about the evolution of the dust that forms Earth-like planets. Here we report spatially resolved detections and compositional analyses of these building blocks in the innermost two astronomical units of three proto-planetary disks. We find the dust in these regions to be highly crystallized, more so than any other dust observed in young stars until now. In addition, the outer region of one star has equal amounts of pyroxene and olivine, whereas the inner regions are dominated by olivine. The spectral shape of the inner-disk spectra shows surprising similarity with Solar System comets. Radial-mixing models naturally explain this resemblance as well as the gradient in chemical composition. Our observations imply that silicates crystallize before any terrestrial planets are formed, consistent with the composition of meteorites in the Solar System.     

Immunogenicity of recombinant fowl-pox virus co-expressing structural protein precursor P1-2A and proteinase 3C of FMDV

Two recombinant plasmids, pUTA2P1 and pUTAL3CP1, were constructed by inserting structural protein precursor P1-2A and proteinase 3C of foot-and-mouth disease virus (FMDV) into fowl-pox virus (FPV) recombinant vectors pUTA-2 and pUTA-16-LacZ respectively, and two recombinant FPVs (vUTA2P1 and vUTAL3CP1) screened by the RT-PCR, IFA assay and Western blotting assay were obtained successfully. Mice injected respectively with rFPVs were induced high level specific anti-FMDV antibodies, increasing of T subtypes, and higher cytotoxicities of splenocytes than those of control groups. These results indicated that a new method was used to construct a potential candidate vaccine of FMDV.     

学习"三个代表"思想 创新高校思想政治工作

从马克思主义哲学和伦理学的视角论证了“三个代表”的内在辩证关系及伟大意义,指出高校思想政治工作必须按照“三个代表”的要求,加大思想政治工作的科技含量,加强思想政治工作的体制创新,思政工作的创新关键是以人为本,重在实践。     

Respective roles of short-and long-range interactions in protein folding

A new method was presented to discuss the respective roles of short- and long-range interactions in protein folding. It‘s based on an off-lattice model, which is also being called as toy model. Simulated annealing algorithm was used to search its native conformation. When it is applied to analysis proteins lagt and laho, we find that helical segment catmot fold into native conformation without the influence of long-range interactions. That‘s to say that long-range interactions are the main determinants in protein folding.     

影响外语课堂教学的文化因素探讨

通过问卷调查、课堂观察等形式的英语课堂教学研究表明,应当高度重视影响外语课堂教学的文化因素,因为这些因素具有内在的、不可忽视的作用。外语教学中纯粹的"拿来主义"是不可行的,在引进国外先进的教材与教学方法时,应尊重并结合本国文化的特点,对之进行适当的调整和改造。     

Mathematical model of cylindrical form tolerance

Tolerance is essential for integration of CAD and CAM. Unfortunately, the meaning of tolerances in the national standard is expressed in graphical and language forms and is not adaptable for expression, processing and data transferring with computers. How to interpret its semantics is becoming a focus of relevant studies. This work based on the mathematical definition of form tolerance in ANSI Y14.5.1M-1994, established the mathematical model of form tolerance for cylindrical feature. First, each tolerance in the national standard was established by vector equation. Then on the foundation of tolerance's mathematical definition theory, each tolerance zone's mathematical model was established by inequality based on degrees of feature. At last the variance area of each tolerance zone is derived. This model can interpret the semantics of form tolerance exactly and completely.     

Distributed collaborative CAD system based on Web Service

This paper presents a novel Web Service based distributed collaborative CAD system employing feature as its collaborative design element and uses XML to define feature operations and communication protocol between the server and the client. To reduce network load and increase response ability of the system, the feature information is updated incrementally on the client. The system supports collaborative designing on heterogeneous platforms. Its framework and communication protocols are analyzed in detail. The experimental results from the developed prototype system showed that it can effectively support collaborative design under the distributed environment.     

MRS study on lentiform nucleus in idiopathic Parkinson‘s disease with unilateral symptoms

OBJECTIVE: To investigate changes in magnetic resonance spectroscopy (MRS) of lentiform nucleus during the early stage of Parkinson's disease. METHODS: Twenty-five patients with idiopathic Parkinson disease with unilateral symptoms (IPDUS) and 25 healthy volunteers were enrolled in this study. MRS of the lentiform nucleus in each patient was taken and then concentrations of N-acetylaspartate (NAA), Creatine (Cr) and Choline (Cho) were calculated. RESULTS: Compared to that in the control, NAA/ (Cho+Cr) was significantly lower in the lentiform nucleus contralateral to symptoms and even that in the ipsilateral side in IPDUS patients (all P<0.05); while there was no difference between the two sides in the healthy volunteer (P>0.05). The ratio of NAA/(Cho+Cr) ipsilateral to the sympatomatic side of the patient was also lower than that of the control (P<0.05). CONCLUSIONS: There might be some changes with MRS on the lentiform nucleus during the early stage of idiopathic Parkinson's disease with unilateral symptom. MRS may be one of the reliable methods for early or even sub-clinical diagnosis.     

马克思“三大社会形态说”的内涵及其现实意义

在《1857-1858年经济学手稿》中,马克思从人的发展的角度把人类社会划分为人的依赖关系、物的依赖关系、自由个性三种社会形态。马克思的“三大社会形态说”在当代中国具有非常重要的现实意义,它有助于我们正确理解马克思主义的唯物史观,科学地解释有中国特色的社会主义实践,正确认识和处理社会主义市场经济与人的全面发展的关系。     

略论把流通业提升为先导产业(一)

流通业的兴起具有深刻的经济渊源。把流通业提升为先导产业是社会主义市场经济体制初步确立、“生产相对过剩”和加入WTO新形势的必然要求。将这一要求转化成政策并付诸实践,需要我们大胆创新,确立相应的软环境和硬环境。