Properties of PVA-PSA hybrid materials prepared through the incorporation of polysilicic acid (PSA) into polyvinyl alcohol

A quick method of preparing transparent organic-inorganic hybrid material was studied. The hybrid, PVA/PSA, was prepared through incorporating the nanoscaled polysilicic acid (PSA) obtained through hydrolysis and condensation of metasilicate salt directly into a polyvinyl alcohol (PVA). The interfacial force, microstructure, and dynamic mechanical property of the hybrid were studied by means of spectroscopy (FTIR, X-ray diffraction and solid-state ²⁹Si NMR) and dynamic mechanical analysis, and the results were compared with that of the hybrids, PVA/TEOS, prepared through the traditional sol-gel process. It was found that the microstructure of PVA/PSA was different from that of PVA/TEOS because of the different preparation methods. The structures of the crystals in both hybrids were similar to that of the pure PVA. Other physical properties, such as T_g, storage modulus, tensile strength and solvent resistance of the PVA/PSA hybrid, were improved significantly with the addition of the silica content. The extent of improvement was a little lower than that for the PVA/TEOS.     

GaAs PIN electro-optic travelling-wave modulator at 1.3 ?m

A GaAs PIN travelling-wave modulator operated at 1.3 ?m has been fabricated from material grown by organometallic vapour phase epitaxy (OMVPE) on an n+ (100) GaAs substrate. The device has a constant V? of 8 V from DC to 10 GHz and an optical extinction ratio of 13 dB. The optical insertion loss of the device is 3.5 dB, and the 3 dB frequency bandwidth is measured to be 4.1 GHz, which is limited by the microwave slowing induced by the n+ substrate.     

A brief assessment of concerns associated with genetic testing for cancer: The multidimensional impact of cancer risk assessment (MICRA) questionnaire.

The Multidimensional Impact of Cancer Risk Assessment (MICRA) is a new tool to measure the specific impact of result disclosure after genetic testing. The authors compared its performance with that of questionnaires measuring general and cancer-specific distress. Participants (158 women) responded 1 month after they received genetic test results. The women were divided into 4 standard clinical test result groups: BRCA1/2 positive, BRCA1/2 negative, panel negative, and true negative. Factor analysis supported the formation of 3 subscales: Distress (6 items, α= .86), Uncertainty (9 items, α= .77), and Positive Experiences (4 items, α= .75). All 3 MICRA subscales differentiated participants who were BRCAI/2 positive from the other 3 groups. MICRA thus helps identify subgroups of vulnerable genetic testing participants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Real-Time Access Control and Reservation on B-Tree Indexed Data

This paper proposes methodologiesto control the access of B⁺-tree-indexed datain a batch and firm real-time fashion. Algorithms are proposedto insert, query, delete, and rebalance B⁺-tree-indexeddata based on the non-real-time algorithms proposed in Kerttu,Eljas, and Tatu (1996) and the idea of priority inheritance (Sha,Rajkumar, and Lehoczky, 1990). We propose methodologies to reducethe number of disk I/O to improve the system performancewithout introducing more priority inversion. When the schedulabilityof requests with critical timing constraints is highly important,we propose a mechanism for data reservation based on the ideaof preemption level and the Stack Resource Policy (Baker, 1990).The performance of our methodologies was evaluated by a seriesof experiments, from which we have obtained encouraging results.     

Analyzing the alternative shutdown cooling behaviors for Chinshan Nuclear Power Plant using CFD simulation

The Chinshan Nuclear Power Plant (CSNPP) is a GE-designed BWR4 plant, having two identical units with rated core thermal power of 1804 MWt each unit. Several alternative shutdown cooling methods driven by natural or mixed convection has been proposed by the plant for studying the core cooling capability when the Residual Heat Removal (RHR) systems are not available or the refueling tasks, such as the In Vessel Visual Inspection (IVVI) work etc., is being proceeded. One of the examples is to connect a pipe from the outlet of the new spent fuel heat exchanger to the reactor cavity. The design of the alternatives shall ensure that the maximum core fluid temperature is limited below the boiling temperature of water. In this study, a Computational Fluid Dynamics (CFD) model is developed to analyze the natural convection phenomena during the shutdown period. Through a series of assumption, modeling and meshing processes, a calculation domain with approximate four million meshes including the RPV, reactor cavity and spent fuel pool, have been solved in this study. The analysis results showed that the passive alternative shutdown cooling system could provide sufficient heat removal capability to maintain the maximum core fluid temperature below boiling temperature. The results also indicated that the alternative shutdown cooling system could be served as an appropriate solution for CSNPP when the RHR is inoperable.     

Effect of Ru addition on the properties of Al-doped ZnO thin films prepared by radio frequency magnetron sputtering on polyethylene terephthalate substrate

The addition of ruthenium in aluminum-doped zinc oxide transparent conducting thin films was deposited on polyethylene terephthalate at 20 °C by radio frequency magnetron sputtering technique. The structure and electrical properties of the films were investigated with respect to variation of Ru concentration. The XRD and FESEM results show that the film with 0.5 wt% Ru doping has the best crystallinity and larger pyramid-like grains, therefore the resistivity reached to a lowest value of 9.1 × 10⁻⁴ Ωcm. The low carrier mobilities of the films (3–7.2 cm² V⁻¹ s⁻¹), however, were limited by ionized impurity scattering and grain boundary scattering mechanisms since the carrier concentrations were ranged from 2.2 × 10²⁰ to 9.5 × 10²⁰ cm⁻³. The transmittance in the visible is greater than 80% with the optical band gap in the order of 3.352–3.391 eV.     

Alpha 2-antiplasmin causes thrombi to resist fibrinolysis induced by tissue plasminogen activator in experimental pulmonary embolism

BACKGROUND: In patients with pulmonary embolism, thrombi resist fibrinolysis induced by plasminogen activators. Because the molecular basis of this thrombus resistance is poorly understood, we used a potent inhibitor to examine the potential role of alpha 2-antiplasmin (alpha 2AP) in experimental pulmonary embolism. METHODS AND RESULTS: Lysis of experimental pulmonary emboli was measured 4 hours after embolization in anesthetized ferrets. All animals received heparin (100 U/kg). Five experimental groups were studied: (1) no recombinant tissue plasminogen activator (rTPA); (2) rTPA at 1 mg/kg; (3) rTPA at 2 mg/kg; (4) rTPA at 1 mg/kg plus a control monoclonal antibody (MAb); and (5) rTPA at 1 mg/kg plus an alpha 2AP inhibitor (MAb 77A3). In comparison with ferrets receiving no rTPA (15.6 +/- 10.5% lysis, mean +/- SD), rTPA-treated groups showed significantly greater lysis (P < .01). Animals treated with rTPA and alpha 2AP inhibitor (56.2 +/- 4.7% lysis) showed significantly greater lysis than all other treatment groups, including ferrets treated with the same dose of rTPA alone (38.5 +/- 6.3%, P < .01), with twice the rTPA dose alone (45.0 +/- 6.5%, P < .05), or with a control MAb (35.2 +/- 4.6%, P < .01). The combination of rTPA treatment and alpha 2AP inhibition caused no consumption of fibrinogen. CONCLUSIONS: Inhibition of alpha 2AP significantly amplified the lysis of experimental pulmonary emboli by rTPA without increasing fibrinogen consumption. These results suggest that alpha 2AP may play an important role in thrombus resistance in patients with venous thromboembolism.     

Properties of the GaAs oxide layer grown by the liquid-phase chemical-enhanced technique on the S-passivated GaAs surface

The properties of GaAs oxide layers prepared by liquid-phase chemical-enhanced oxidation of the (NH₄)₂S_x-passivated GaAs surface are investigated. The initial oxidation rate is suppressed and the refractive indices of oxide layers are lower after S passivation. In accordance with the depth profiles measured by secondary ion mass spectroscopy (SIMS), a model is proposed to illustrate the chemical composition of the oxide layer grown by liquid-phase chemical-enhanced oxidation after S passivation. Oxidation following different surface treatments was studied by analyzing their activation energies. In addition, we find that the leakage current and the breakdown electric field of oxide layers can be improved significantly with the passivation technique.