Bacterial DNA sample preparation from whole blood using surface-modified Si pillar arrays

A novel bacterial DNA sample preparation device for molecular diagnostics has been developed. On the basis of optimized conditions for bacterial adhesion, surface-modified silicon pillar arrays for bacterial cell capture were fabricated, and their ability to capture bacterial cells was demonstrated. The capture efficiency for bacterial cells such as Escherichia coli, Staphylococcus epidermidis, and Streptococcus mutans in buffer solution was over 75% with a flow rate of 400 microL/min. Moreover, the proposed method captured E. coli cells present in 50% whole blood effectively. The captured cells from whole blood were then in- situ lyzed on the surface of the microchip, and the eluted DNA was successfully amplified by qPCR. These results demonstrate that the full process of pathogen capture to DNA isolation from whole blood could be automated in a single microchip.     

High performance of a solid-state flexible asymmetric supercapacitor based on graphene films

Solid-state flexible energy storage devices hold the key to realizing portable and flexible electronic devices. Achieving fully flexible energy storage devices requires that all of the essential components (i.e., electrodes, separator, and electrolyte) with specific electrochemical and interfacial properties are integrated into a single solid-state and mechanically flexible unit. In this study, we describe the fabrication of solid-state flexible asymmetric supercapacitors based on an ionic liquid functionalized-chemically modified graphene (IL-CMG) film (as the negative electrode) and a hydrous RuO(2)-IL-CMG composite film (as the positive electrode), separated with polyvinyl alcohol-H(2)SO(4) electrolyte. The highly ordered macroscopic layer structures of these films arising through direct flow self-assembly make them simultaneously excellent electrical conductors and mechanical supports, allowing them to serve as flexible electrodes and current collectors in supercapacitor devices. Our asymmetric supercapacitors have been optimized with a maximum cell voltage up to 1.8 V and deliver a high energy density (19.7 W h kg(-1)) and power density (6.8 kW g(-1)), higher than those of symmetric supercapacitors based on IL-CMG films. They can operate even under an extremely high rate of 10 A g(-1) with 79.4% retention of specific capacitance. Their superior flexibility and cycling stability are evident in their good performance stability over 2000 cycles under harsh mechanical conditions including twisted and bent states. These solid-state flexible asymmetric supercapacitors with their simple cell configuration could offer new design and fabrication opportunities for flexible energy storage devices that can combine high energy and power densities, high rate capability, and long-term cycling stability.     

Measuring children's perceptions of their mother's depression: The Children’s Perceptions of Others’ Depression Scale–Mother Version.

Several theoretical perspectives suggest that knowledge of children's perceptions of and beliefs about their parents' depression may be critical for understanding its impact on children. This paper describes the development and preliminary evidence for the psychometric properties of a new measure, the Children's Perceptions of Others' Depression – Mother Version (CPOD-MV), which assesses theoretically and empirically driven constructs related to children's understanding and beliefs about their mothers' depression. These constructs include children's perceptions of the severity, chronicity, and impairment of their mothers' depression; self-blame for their mother's depression; and beliefs about their abilities to deal with their mother's depression. The CPOD-MV underwent two stages of development: (1) a review of the literature to identify key constructs, focus groups to help generate items, and clinicians' ratings on the relevance and comprehensibility of the drafted items and (2) a study of the measure's psychometric properties. The literature review, focus groups, and item-reduction techniques yielded a 21-item measure. Reliability, factor structure, and discriminant, convergent, and concurrent validity were tested in a sample of 10- to 17-year-old children whose mothers had been treated for depression. The scale had good internal consistency; factor structure suggestive of a single construct; and discriminant, concurrent, convergent, and incremental validity, suggesting the importance of measuring children's perceptions of their mothers' depression beyond knowledge of mothers' depression symptom level when explaining which children have the greatest risk for emotional and behavioral problems among children of depressed mothers. These findings support continued development and beginning clinical applications of the scale. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A Study in the Thermodynamic Behavior of Nickel in the MgO‐SiO2‐FeO Slag System

The dissolution behavior of nickel in the MgO‐SiO₂‐FeO slag system was investigated by using the thermodynamic equilibrium technique. Nickel distribution ratio between molten MgO‐SiO₂‐FeO slag and molten Fe‐Ni alloy at 1773 K and 1873 K was measured to understand the dissolution mechanism of nickel into the slags. In particular, the effect of oxygen potential and basicity on the distribution of nickel was investigated. Nickel distribution between slag and Fe‐Ni alloy increased with higher oxygen potential showing a slope of 1/2. For basic slag systems near the olivine saturated composition, the nickel distribution ratio increased with higher basicity and for acidic slag systems near the cristobalite saturated composition, the nickel distribution ratio decreased with higher basicity. Thus, the nickel dissolution into the MgO‐SiO₂‐FeO slag system showed two independent mechanisms similar to that found in the CaO‐SiO₂‐CaF₂ system. The contour of the iso distribution ratio was represented in the MgO‐SiO₂‐FeO ternary phase diagram. From the results, an optimum slag composition was determined to be near the olivine saturated with approximately $X_{MgO} /X_{SiO_{2} } $ of 0.8 at 1773 K and 1.0 at 1873 K.     

Size-controlled cubic coordination polymer nanoparticles from chiral dipyridyl Zn-salen

Size-controlled crystalline nanocubic coordination polymer particles from chiral Zn-salen and Co(II) have been obtained. PXRD patterns show that these particles have an identical unit cell regardless of a wide range of size distributions. Furthermore, cubic particles with epitaxial layers have been obtained with a simple manipulation during the synthesis.     

使用校直辊工艺简易模拟方法的单层钢丝帘线质量评估

用作汽车轮胎增强材料的钢丝帘线是由盘条拉成细丝捻制而成。为满足轮胎的刚度需求,人们开发了不同类型的钢丝帘线。钢丝帘线的结构稳定性是其质量评估的重要因素之一。一般在钢丝帘线捻制工序后评估钢丝帘线的平直性和残余扭转。校直辊是利用周期弯曲变形来改善钢丝帘线的平直性和残余应力的一种装置。校直辊装置的工艺设计大多数情况下是基于工程师经验的反复试验,需要大量的时间和成本。因此需要一个有效工具来节省校直辊工艺设计的时间和成本。有限元分析模拟方法是校直辊工艺设计的一种有效选择。本工作提出通过有限元分析校直辊工艺数值模拟单层钢丝帘线质量的评估方法,以3×0.30单层钢丝帘线作为试验样品。简易模拟方法如     

Aptamer-modified magnetic nanoprobe for molecular MR imaging of VEGFR2 on angiogenic vasculature

Nucleic acid-based aptamers have been developed for the specific delivery of diagnostic nanoprobes. Here, we introduce a new class of smart imaging nanoprobe, which is based on hybridization of a magnetic nanocrystal with a specific aptamer for specific detection of the angiogenic vasculature of glioblastoma via magnetic resonance (MR) imaging. The magnetic nanocrystal imaging core was synthesized using the thermal decomposition method and enveloped by carboxyl polysorbate 80 for water solubilization and conjugation of the targeting moiety. Subsequently, the surface of the carboxylated magnetic nanocrystal was modified with amine-functionalized aptamers that specifically bind to the vascular growth factor receptor 2 (VEGFR2) that is overexpressed on angiogenic vessels. To assess the targeted imaging potential of the aptamer-conjugated magnetic nanocrystal for VEGFR2 markers, the magnetic properties and MR imaging sensitivity were investigated using the orthotopic glioblastoma mouse model. In in vivo tests, the aptamer-conjugated magnetic nanocrystal effectively targeted VEGFR2 and demonstrated excellent MR imaging sensitivity with no cytotoxicity.     

Collapse simulation of tubular structures using a finite element limit analysis approach and shell elements

This paper describes the collapse simulation of thin-walled tubular structures using a finite element limit analysis approach and degenerated four-node shell elements. The simulation traces the path of sequential deformation of the structure modelled by considering the strain-hardening effect, which is important for the analysis of collapse behaviour and energy absorption efficiency. The collapse analysis of some square tubes was used to verify the simulation method proposed. Numerical results are compared with experimental observations for sequential collapse loads and deformation modes, showing fairly good coincidence. The collapse analysis of an S-rail was then carried out for sequential collapse loads as well as deformation modes and its results are compared with elasto-plastic analysis results obtained from the explicit dynamic code PAM-CRASH. The energy absorption capacity was studied for a variety of rectangular cross-section aspect ratios. The results show that the energy absorption capacity increases as the height-to-width aspect ratio becomes larger. Results also demonstrate that the finite element limit analysis can predict the plastic collapse load and collapse mode of thin-walled structures efficiently and systematically. The present algorithm with a simple formulation has the advantage of stable convergence, computational efficiency and easy access to strain-hardening materials compared to the incremental rigid–plastic finite element analysis.     

Effects of microstructural evolution and intermetallic layer growth on shear strength of ball-grid-array Sn-Cu solder joints

The shear strength of ball-grid-array (BGA) solder joints on Cu bond pads was studied for Sn-Cu solder containing 0, 1.5, and 2.5 wt.% Cu, focusing on the effect of the microstructural changes of the bulk solder and the growth of intermetallic (IMC) layers during soldering at 270°C and aging at 150°C. The Cu additions in Sn solder enhanced both the IMC layer growth and the solder/IMC interface roughness during soldering but had insignificant effects during aging. Rapid Cu dissolution from the pad during reflow soldering resulted in a fine dispersion of Cu₆Sn₅ particles throughout the bulk solder in as-soldered joints even for the case of pure Sn solder, giving rise to a precipitation hardening of the bulk solder. The increased strength of the bulk solder caused the fracture mode of as-soldered joints to shift from the bulk solder to the solder/IMC layer as the IMC layer grew over a critical thickness about 1.2 m for all solders. The bulk solder strength decreased rapidly as the fine Cu₆Sn₅ precipitates coarsened during aging. As a consequence, regardless of the IMC layer thickness and the Cu content of the solders, the shear strength of BGA solder joints degraded significantly after 1 day of aging at 150°C and the shear fracture of aged joints occurred in the bulk solder. This suggests that small additions of Cu in Sn-based solders have an insignificant effect on the shear strength of BGA solderjoints, especially during system use at high temperatures.