Label-free immunodetection with CMOS-compatible semiconducting nanowires

Semiconducting nanowires have the potential to function as highly sensitive and selective sensors for the label-free detection of low concentrations of pathogenic microorganisms. Successful solution-phase nanowire sensing has been demonstrated for ions, small molecules, proteins, DNA and viruses; however, 'bottom-up' nanowires (or similarly configured carbon nanotubes) used for these demonstrations require hybrid fabrication schemes, which result in severe integration issues that have hindered widespread application. Alternative 'top-down' fabrication methods of nanowire-like devices produce disappointing performance because of process-induced material and device degradation. Here we report an approach that uses complementary metal oxide semiconductor (CMOS) field effect transistor compatible technology and hence demonstrate the specific label-free detection of below 100 femtomolar concentrations of antibodies as well as real-time monitoring of the cellular immune response. This approach eliminates the need for hybrid methods and enables system-scale integration of these sensors with signal processing and information systems. Additionally, the ability to monitor antibody binding and sense the cellular immune response in real time with readily available technology should facilitate widespread diagnostic applications.     

Electromagnetic detection of a 410-km-deep melt layer in the southwestern United States

A deep-seated melt or fluid layer on top of the 410-km-deep seismic discontinuity in Earth's upper mantle, as proposed in the transition-zone 'water filter' hypothesis, may have significant bearing on mantle dynamics and chemical differentiation. The geophysical detection of such a layer has, however, proved difficult. Magnetotelluric and geomagnetic depth sounding are geophysical methods sensitive to mantle melt. Here we use these methods to search for a distinct structure near 410-km depth. We calculate one-dimensional forward models of the response of electrical conductivity depth profiles, based on mineral physics studies of the effect of incorporating hydrogen in upper-mantle and transition-zone minerals. These models indicate that a melt layer at 410-km depth is consistent with regional magnetotelluric and geomagnetic depth sounding data from the southwestern United States (Tucson). The 410-km-deep melt layer in this model has a conductance of 3.0 x 10(4) S and an estimated thickness of 5-30 km. This is the only regional data set that we have examined for which such a melt layer structure was found, consistent with regional seismic studies. We infer that the hypothesized transition-zone water filter occurs regionally, but that such a layer is unlikely to be a global feature.     

Circular polarimetry reveals helical magnetic fields in the young stellar object HH 135-136

Magnetic fields are believed to have a vital role in regulating and shaping the flow of material onto and away from protostars during their initial mass accretion phase. It is becoming increasingly accepted that bipolar outflows are generated and collimated as material is driven along magnetic field lines and centrifugally accelerated off a rotating accretion disk. However, the precise role of the magnetic field is poorly understood and evidence for its shape and structure has not been forthcoming. Here we report imaging circular polarimetry in the near-infrared and Monte Carlo modelling showing that the magnetic field along the bipolar outflow of the HH 135-136 young stellar object is helical. The field retains this shape for large distances along the outflow, so the field structure can also provide the necessary magnetic pressure for collimation of the outflow. This result lends further weight to the hypothesis--central to any theory of star formation--that the outflow is an important instrument for the removal of high-angular-momentum material from the accretion disk, thereby allowing the central protostar to increase its mass.     

Optical parameters induced by phase transformation in RF magnetron sputtered TiO2nanostructured thin films

Pure TiO2 thin films were deposited onto quartz substrates using a ceramic TiO2 target at an elevated substrate temperature of 573 K by RF magnetron sputtering, and an analysis of structural, optical and photoluminescence characteristics of the films upon phase transformation is reported in this paper. Structural investigations using X-ray diffraction revealed that the as-deposited film was amorphous in nature. Thermal annealing for 2 h at 873 K in air resulted in the formation of anatase phase, and a phase transformation to rutile was observed at 1073 K.An increase in grain size and an improvement in crystallinity were also observed on annealing. Rod- like rutile crystallites were observed in the SEM images of the film annealed at 1273 K. As-deposited films and films annealed up to 1073 K were highly transparent in the visible region with a transparency 480%. Optical band gap of the films decreased upon thermal annealing which is attributed to phase transformation from amorphous to anatase and then to rutile. Optical parameters such as refractive index, optical conductivity and optical dielectric constant increased with increase in annealing temperature. Since rutile is the optically active phase, the superior refractive index of the film annealed at 1073 K along with its high transparency in visible region suggests the application of this film in antireflective coatings. Photoluminescence emission of maximum intensity was observed for the film annealed at 873 K, which exhibits anatase phase. Intense blue emission observed in this film makes it suitable for use in optoelectronic display devices.     

面向语义检索应用的本体模型结构设计

为提高语义检索过程中术语关系自动判别的效果,引入本体理论,对本体的结构设计及推理机理展开研究。提出基于6元组的本体模型结构,采用描述逻辑作为表达工具,实现了对原子术语、复合术语、实例、实例描述、属性分配以及公理的语义描述。依据Gruber设计原则,从明确性和客观性、一致性、最大单向可扩展性、最小编码偏好和最小本体承诺5方面对本体结构进行评价。从语义检索的需求出发,提出面向术语和面向实例的两种推理类型,以及转换机制和判定算法。将语义检索抽象成信息请求与答复过程,提出4类信息搜索策略,并对语义检索系统的实现进行展望。     

Deformation of the lowermost mantle from seismic anisotropy

The lowermost part of the Earth's mantle-known as D″-shows significant seismic anisotropy, the variation of seismic wave speed with direction. This is probably due to deformation-induced alignment of MgSiO(3)-post-perovskite (ppv), which is believed to be the main mineral phase present in the region. If this is the case, then previous measurements of D″ anisotropy, which are generally made in one direction only, are insufficient to distinguish candidate mechanisms of slip in ppv because the mineral is orthorhombic. Here we measure anisotropy in D″ beneath North and Central America, where material from subducting oceanic slabs impinges on the core-mantle boundary, using shallow as well as deep earthquakes to increase the azimuthal coverage in D″. We make more than 700 individual measurements of shear wave splitting in D″ in three regions from two different azimuths in each case. We show that the previously assumed case of vertical transverse isotropy (where wave speed shows no azimuthal variation) is not possible, and that more complicated mechanisms must be involved. We test the fit of different MgSiO(3)-ppv deformation mechanisms to our results and find that shear on (001) is most consistent with observations and the expected shear above the core-mantle boundary beneath subduction zones. With new models of mantle flow, or improved experimental determination of the dominant ppv slip systems, this method will allow us to map deformation at the core-mantle boundary and link processes in D″, such as plume initiation, to the rest of the mantle.     

银合欢壳多糖酶在转基因Khao Da wk Mali 105籼稻中的表达(英文)

通过含有pCAMBIA1300载体(抗潮霉素基因(hpt)作为选择标记基因)的根癌农杆菌菌株EHA105的介导,将326个银合欢I型碱性壳多糖酶基因(KB3,GenBank登录号为:AAM49597)的氨基酸导入到籼稻Khao Dawk Mali 105(KDML 105)植株中,获得了KDML 105籼稻的愈伤组织。pCAMBIA1300载体包含有CaMV35S启动子、银合欢壳多糖酶基因和NOS终止子。在NB培养基的水稻秧苗中愈伤组织的转化率为94%.在培养温度为28℃,以含有4 mg/l BAP和7 g/l植物凝胶再生培养基的条件下,愈伤组织的再生频率高达80%.为了建立一个KDML 105农杆菌转化方法,考察了各方面的因素。共培养期间,在培养基中添加50μM的乙酰丁香酮对提高瞬时转化率非常重要。4周龄的盾片衍生的愈伤组织是最佳的起始材料。添加40 mg/l潮霉素和400 mg/l头孢霉素的NB培养基是水稻愈伤组织选择性转化的最佳培养基,其转化率达到78%.采用PCR、Northern Blot杂交凝胶、Southern Blot杂交凝胶和GUS分析技术研究了愈伤组织和转基因水稻中的壳多糖酶和gus基因的表达。壳多糖酶和gus基因在水稻的多个部位被检测到,包括愈伤组织、叶、根、茎和秧苗,但是它们在水稻根部的含量较少。抗真菌的水稻壳多糖酶表现出抗串珠镰刀菌的性质。     

Manufacturing and services: From mass production to mass customization

Manufacturing and services constitute two of the five sectors of every country’s economy;depending on the maturity of the economy,they are-in terms of employment-typically the two largest sectors.The outputs or products of an economy can also be divided into goods products(due to manufacturing,construction,agriculture and mining) and services products.To date,the goods and services products have,for the most part,been mass produced;it is the premise of this paper that recent technological advances-including flexible manufacturing,cloud computing,nanotechnology and smart sensing-can better enable the transformation from mass production to mass customization.We regard mass customization as the simultaneous and real time management of supply and demand chains,based on a taxonomy that can be defined in terms of its underpinning component and management foci.From a components perspective,we first consider the value chain of supplier,manufacturer,assembler,retailer,and customer,and then develop a consistent set of definitions for supply and demand chains based on the location of the customer order penetration point.From a management perspective,we classify the methods that are employed in the management of these chains,based on whether supply and/or demand are flexible or fixed.Interestingly,our management taxonomy highlights a very critical research area at which both supply and demand are flexible,thus manageable.Simultaneous management of supply and demand chains sets the stage for mass customization which is concerned with meeting the needs of an individualized customer market.Simultaneous and real time management of supply and demand chains set the stage for real time mass customization(e.g.,wherein a tailor first laser scans an individual’s upper torso and then delivers a uniquely fitted jacket within a reasonable period,while the individual is waiting).The benefits of real time mass customization cannot be over-stated as goods and services become indistinguishable and are co-produced-as "servgoods"-in real time,resulting in an overwhelming economic advantage.     

论清朝前期对新疆南疆地区实行民族隔离政策的危害

清朝统一新疆以后,为巩固西北边防,抵御沙俄侵略,稳定社会秩序,维护国家统一,采取了一些具有地方特色的民族政策。在南疆实行的民族隔离政策则对新疆的发展埋下了一定的政治隐患。     

永生细胞系,体细胞和生殖腺细胞中端粒酶活性检测

用TRAP法对来自人肺、乳腺和皮肤的恶性肿瘤永生细胞系．和该三种组织来源的正常体细胞,及正常卵巢和睾丸组织进行了端粒酶活性检测。结果发现,三种永生细胞系和卵巢与睾丸组织中均可测到端粒酶活性,而三种组织来源的体细胞不能测到;提示端粒酶可能对恶性肿瘤细胞永生化、生物种系正常繁衍,和正常体细胞的衰老与寿命起着重要的决定作用。