[Show abstract][Hide abstract] ABSTRACT: Polytetrafluoroethylene (PTFE) films were homogeneously coated onto aluminum powders. The synthesized PTFE-coated aluminum (PTFE/Al) powders showed a microstructure of spherical Al powders covered with PTFE film of a few hundreds of nm in thickness. The PTFE/Al powders showed significantly increased gravimetric energy of 4.80 kJ g−1 compared to the value of 0.88 kJ g−1 for pure Al powders during oxidation in a temperature range of 25–1450 °C. It was found that the PTFE/Al interface mixed with oxygen and fluorine atoms provided a vigorous oxidation of the Al powders. These results clearly confirm that the PTFE layer acts as a protective layer and an oxidation helper.
[Show abstract][Hide abstract] ABSTRACT: In the era
of big data
the virtual machine
(VM) environment is important where multiple VMs of different operating system and application can be simultaneously run on the same host. In the VM environment the conventional hard disk drive (HDD) has limitations such as low random access performance and high power consumption. Solid State Drive (SSD) is an emerging storage technology, playing a critical role in revolutionizing the storage system design. Recently, SSD storage caching is widely studied for VM-based systems. The existing works on cache space allocation identify the space demand of each VM based on hit ratio. They are not effective for the VMs of shared SSD cache due to the filte ring effect of higher-level caches. In this paper we propose a novel hypervisor-based SSD caching scheme, employing a new metric to accurately determine the demand on SSD cache space of each VM. Computer simulation confirms that it substantially improves the accuracy of cache space allocation compared to the existing schemes. It also allows to display comparable hit ratio as the existing schemes with less amount of SSD cache for the VMs.
[Show abstract][Hide abstract] ABSTRACT: Aluminum powders with average diameters of 24, 45, and 75 mu m were homogeneously coated with nickel through an electroless plating process. The effect of nickel coating on the thermal oxidation behavior of the aluminum powders was clearly confirmed by observing the variation of the weight gain during thermal gravimetric analysis in an air atmosphere. The results obtained from differential scanning calorimetry showed that the exothermic enthalpy values of the aluminum powders increased significantly with decrease in the powder size from 75 mu m to 25 mu m. Furthermore, the nickel-coated aluminum powders exhibited much higher exothermic enthalpy values than those of pure aluminum powders. It was found that nickel coated onto aluminum powders plays an important role as a protective layer, preventing pure aluminum powders from undergoing surface oxidation while also providing exothermic heat through a self-propagating high-temperature synthetic reaction between the nickel and the aluminum. These results indicate that nickel coating should be considered to achieve high reactivity in aluminum powders for energetic applications.
No preview · Article · Dec 2015 · Taehan-Kŭmsok-Hakhoe-chi = Journal of the Korean Institute of Metals and Materials
[Show abstract][Hide abstract] ABSTRACT: Ultra-fine grained Al2O3 was fabricated by in-situ spark plasma sintering (SPS) process directly from amorphous powders. During in-situ sintering, phase transformation from amorphous to stable α-phase was completed by 1100 °C. High relative density over 99% of in-situ sintered Al2O3 was obtained in the sintering condition of 1400 °C under 65 MPa pressure without holding time. The grain size of in-situ sintered Al2O3 body was much finer (~400 nm) than that of Al2O3 sintered from the crystalline α-Al2O3 powders. For in-situ sintered Al2O3 from amorphous powders, we observed a characteristic microstructural feature of highly elongated grains in the ultra-fine grained matrix due to abnormal grain growth. Moreover, the properties of abnormally grown grains were controllable. Fracture toughness of in-situ sintered Al2O3 with the elongated grains was significantly enhanced due to the self-reinforcing effect via the crack deflection and bridging phenomena.
[Show abstract][Hide abstract] ABSTRACT: Intercellular bridges are a conserved feature of spermatogenesis in mammalian germ cells and derive from arresting cell abscission at the final stage of cytokinesis. However, it remains to be fully understood how germ cell abscission is arrested in the presence of general cytokinesis components. The TEX14 (testis-expressed gene 14) protein is recruited to the midbody and plays a key role in the inactivation of germ cell abscission. To gain insights into the structural organization of TEX14 at the midbody, we have determined the crystal structures of the EABR [endosomal sorting complex required for transport (ESCRT) and ALIX-binding region] of CEP55 bound to the TEX14 peptide (or its chimeric peptides) and performed functional characterization of the CEP55-TEX14 interaction by multiexperiment analyses. We show that TEX14 interacts with CEP55-EABR via its AxGPPx3Y (Ala793, Gly795, Pro796, Pro797, and Tyr801) and PP (Pro803 and Pro804) sequences, which together form the AxGPPx3YxPP motif. TEX14 competitively binds to CEP55-EABR to prevent the recruitment of ALIX, which is a component of the ESCRT machinery with the AxGPPx3Y motif. We also demonstrate that a high affinity and a low dissociation rate of TEX14 to CEP55, and an increase in the local concentration of TEX14, cooperatively prevent ALIX from recruiting ESCRT complexes to the midbody. The action mechanism of TEX14 suggests a scheme of how to inactivate the abscission of abnormal cells, including cancer cells.
Preview · Article · Sep 2015 · Proceedings of the National Academy of Sciences
[Show abstract][Hide abstract] ABSTRACT: Probiotics have been used for the treatment of various disorders or as alternative therapies. The stability of dual-coated probiotics is increased in the gastrointestinal environment. The aim of the present study was to evaluate the hepatoprotective effects of dual-coated and uncoated probiotic supplements, following liver injury. Albino Wistar rats were orally treated with probiotics daily and carbon tetrachloride (CCl4) was administered on the seventh and eighth days to induce acute liver damage. Hepatoprotective effects were determined by assessment of serum glutamic–oxaloacetic transaminase (SGOT) and serum glutamic–pyruvic transaminase (SGPT) activities, as well as by histopathological examination. The CCl4-treated control group showed increased SGOT and SGPT activities as compared with the normal control group. However, treatment with probiotics reduced SGOT and SGPT activities, following CCl4 administration. Animals treated with probiotics showed reduced liver weight than that in the standard CCl4 group which did not receive probiotics. Histopathological analysis showed that administration of probiotics minimized liver damage by reducing the level of morphological changes and necrosis. Therefore, probiotics may be effective hepatoprotective agents and should be considered useful for the treatment and prevention of hepatic disorders.
[Show abstract][Hide abstract] ABSTRACT: Tear breakup time (TBUT) is a useful technique for diagnosing dry eye disease (DED). The conventional method of measuring TBUT using fluorescein strips adds supplemental normal saline (NS) to the tear film (wet tear breakup time, WBUT) but does not represent the actual state of the tear film. We introduced a new TBUT method-dry tear breakup time (DBUT)-and investigated its reliability.
We included DED patients with mild symptoms and a Schirmer test of 6 mm or more. Patients using tear substitutes and/or suffering from Sjogren's syndrome were excluded. For measuring DBUT, 1 μl of 5 % fluorescein solution was instilled on the end of an applicator using a micropipette. Once the fluorescein solution was dry, the applicator was sterilized using ethylene oxide gas, and the dried fluorescein was applied to the lower palpebral conjunctiva without supplemental NS. Agreement between the two tests and their sensitivity and specificity were analyzed.
The average age of the patients was 32.1 ± 9.7 years (n = 124). The DBUT was lower than the WBUT, with a mean difference of -0.63 s. Both tests had a low statistically significant correlation with the Ocular Surface Disease Index. When the basis of definite diagnosis for DED was over grade 1 on the Oxford schema of staining, the cutoff value for the WBUT was 4.48 s and the sensitivity and specificity were 0.790 and 0.548 respectively. The area under the receiver operating characteristic (AUROC) curve was 0.609 (95 % confidence interval (CI): 0.517-0.695). When the cutoff value was 3.5 s for the DBUT, the sensitivity and specificity were 0.726 and 0.694 respectively, and the AUROC curve was 0.724 (95 % CI: 0.637-0.801).
DBUT had a higher correlation with symptoms than the conventional WBUT. When DED was diagnosed with corneal or conjunctival staining based on the Oxford schema of staining, DBUT had a better accuracy than the conventional WBUT. DBUT may replace WBUT after confirming studies, especially when surface damage is to be detected as opposed to tear flow or symptoms.
No preview · Article · Jun 2015 · Albrecht von Graæes Archiv für Ophthalmologie
[Show abstract][Hide abstract] ABSTRACT: Carbon nanotube/bismuth-selenium-tellurium composites were fabricated by consolidating CNT/Bi2(Se,Te)3 composite powders prepared from a polyol-reduction process. The synthesized composite powders exhibit CNTs homogeneously dispersed among Bi2(Se,Te)3 matrix nanopowders of 300 nm in size. The powders were densified into a CNT/Bi2(Se,Te)3 composite in which CNTs were randomly dispersed in the matrix through spark plasma sintering process. The effect of an addition of Se on the dimensionless figure-of-merit (ZT) of the composite was clearly shown in 3 vol.% CNT/Bi2(Se,Te)3 composite as compared to CNT/Bi2Te3 composite throughout the temperature range of 298 to 473 K. These results imply that matrix modifications such as an addition of Se as well as the incorporation of CNTs into bismuth telluride thermoelectric materials is a promising means of achieving synergistic enhancement of the thermoelectric performance levels of these materials.
Preview · Article · Mar 2015 · Journal of Nanomaterials
[Show abstract][Hide abstract] ABSTRACT: Despite intensive research on photochemical activation of sol–gel metal oxide materials, the relatively long processing time and lack of deep understanding of the underlying chemical courses have limited their broader impact on diverse materials and applications such as thin-film electronics, photovoltaics, and catalysts. Here, in-depth studies on the rapid photochemical activation of diverse sol–gel oxide films using various spectroscopic and electrical investigations for the underlying physicochemical mechanism are reported. Based on the exhaustive chemical and physical analysis, it is noted that deep ultraviolet-promoted rapid film formation such as densification, polycondensation, and impurity decomposition is possible within 5 min via in situ radical-mediated reactions. Finally, the rapid fabrication of all-solution metal oxide thin-film-transistor circuitry, which exhibits stable and reliable electrical performance with a mobility of >12 cm2 V−1 s−1 and an oscillation frequency of >650 kHz in 7-stage ring oscillator even after bending at a radius of <1 mm is demonstrated.
Full-text · Article · Mar 2015 · Advanced Functional Materials