Search

본고는 말레이시아의 금융자유화 효과를 검증하고자 한다. WTO가 출범한지 20년이 경과하는 기 간 동안 시장개방을 서비스산업까지 확대되었으며, 이는 금융시장 개방을 전 세계적인 추세로 만들었다. 금융시장개방 효과에 대해서 학자, 정책가들 사이에 큰 논쟁이 되었다. 이는 금융자유화가 이익과 함께 위험을 초래하기 때문이다. 따라서 금융자유화가 이익과 위험에 대해 근본적인 원인을 포괄적으로 이해하는 것이 중요하다. 금융자유화 영향에 관련된 문헌들은 서로 상반되는 결과가 많다. 이와 같이 상반되는 연구결과는 간정적인 영향을 간과하고 직접적인 영향에만 집중하기 때문이다. 또 한 금융자유화의 영향에 관한 국가 간 교차연구는 각국의 자유화 절차, 규제의 틀과 시행 및 거시 경 제적 정책을 고려하지 못하기 때문에 완벽한 연구가 어렵다 말레이시아 금융자유화 연구를 통해 우리는 점진적이고 잘 기획된 금융 자유화 정책을 신중하고 현명한 규제와 강력한 거시정책으로 시행 했을 때 금융위기를 효율적으로 극복할 수 있고 나아가 경제성장을 성공적으로 만드는 요인이 될 수 있다는 것을 알 수 있다. 각 국은 금융자유화의 이익과 위험을 인식하여 신중하게 금융자유화를 접근하고 추진하여야 하겠다.

Background We evaluated the effect of isolated off-pump coronary artery bypass grafting on functional ischemic mitral regurgitation (IMR) associated with acute coronary syndrome. Methods Of 1,419 acute coronary syndrome patients who underwent coronary revascularization between 2000 and 2010 (1,324 off-pump and 95 on-pump), 59 OPCAB patients had greater than mild degree functional IMR preoperatively (31 mild to moderate, 23 moderate, 5 severe). Clinical outcomes and results from echocardiography, angiography, and myocardial single-photon emission computed tomography performed early and 1 year postoperatively were analyzed. Results Operative mortality was 5.1% (3 of 59). All survivors underwent early postoperative echocardiograms, which showed 0 patients with worsened IMR; 41 with less than or equal to mild degree residual IMR (NMR group); and 15 with greater than mild degree IMR (RMR group). Myocardial single-photon emission computed tomography revealed that RMR patients had more reversible ischemic myocardial segments preoperatively than NMR patients ( p = 0.009). Successful right coronary revascularization with proven graft patency was a predictor of early improvement of IMR ( p = 0.024). There were no differences in postoperative morbidities between the 2 groups. One-year follow-up echocardiograms demonstrated further improvement in 10 of 13 RMR patients. No patients experienced mitral valve-related events during follow-up. Overall survival and major adverse cardiac event-free survival rates at 5 years were 84.6% and 78.1%, respectively, with no intergroup differences. Conclusions Most functional IMR associated with acute coronary syndrome, including severe degree IMR, improved during the first postoperative year after off-pump coronary artery bypass grafting.

Sb{sub x}Te{sub y} films were potentiostatically electrodeposited from acidic nitric baths at room temperature by controlling the applied potential. Near-stoichiometric Sb{sub 2}Te{sub 3} thin films were obtained at applied potentials between −0.15 and −0.30 V vs. saturated calomel electrode (SCE). Post-annealing in a reducing environment resulted in an improvement in the crystal structure without the evaporation of the Te element. This result was indicated by a significant reduction in the electrical resistance and decrease in the FWHM of the main diffraction peaks. The power factor (σS{sup 2}) increased from 44.2 to 372.1 μW/m K{sup 2} after annealing at 473 K.

We report a Ni-P metallization scheme for low resistance ohmic contacts to n-type Si for silicon solar cells. As-deposited Ni-P contacts to n-type Si showed a specific contact resistance of 6.42 × 10−4 Ω·cm2. The specific contact resistance decreased with increasing thermal annealing temperature. When the Ni-P contact was annealed at 600°C for 30 min in ambient air, the specific contact resistance was greatly decreased, to 6.37 × 10−5Ω·cm2. The improved ohmic property was attributed to the decrease in the work function due to the formation of Ni-silicides from Ni in-diffusion during the thermal annealing process. Effects of the annealing process on the electrical and crystal properties of the contacts were investigated by means of various resistivity measurements (circular transmission line method (c-TLM), 4-point probe), glancing angle x-ray diffraction (GAXRD), and x-ray photoelectron spectroscopy (XPS).

Zinc oxide (ZnO) nanoparticles decorated single walled carbon nanotubes (SWNTs) were electrochemically synthesized where the deposition conditions were systematically explored to tailor the size, density, and microstructure of the ZnO nanoparticles and correlated to the gas sensing performance. Room temperature conductometric detection of various analytes including CO, CO2, NO2, NH3, SO2, H2S with ZnO/SWNT hybrid nanostructures demonstrated uncharacteristic selectivity towards H2S with little to no response for the other analytes examined. Optimal ZnO/SWNTs gas sensor devices showed a significantly increased in H2S sensitivity over unfunctionalized SWNT networks (i.e. 4.96 % per ppmV vs. 0.225 % ppmV) with a lower detection limit in the ppb range. Additionally, the H2S sensing performance was greatly improved by enhancing the crystallinity of ZnO nanoparticles.

Microstructural and electrical properties of potentiostatically electrodeposited ZnO thin films from an aqueous bath were investigated after annealing at different temperatures in Ar and 5% H2/Ar atmospheres. It is confirmed that the bandgap energy of ZnO thin films decreased with annealing from 3.42 to 3.27–3.29 eV by calculating the wavelength of the absorption region. The annealing at temperatures as low as 200 °C decreased the sheet resistance of ZnO thin films because of the extinction of Zn(OH)2 in the atmosphere. In addition, the sheet resistance of ZnO thin films decreased by annealing in a 5% H2 atmosphere, which caused an increase of carrier concentration by hydrogen reduction.

In order to develop electroless-plated Nickel Phosphate (Ni-P) as a contact material for high efficient low-cost silicon solar cells, we evaluated the effect of ambient thermal annealing on the degradation behavior of interfacial adhesion energy between electroless-plated Ni-P and silicon solar cell wafers by applying 4-point bending test method. Measured interfacial adhesion energies decreased from 14.83 to 10.83 J/ after annealing at 300 and , respectively. The X-ray photoelectron spectroscopy analysis suggested that the bonding interface was degraded by environmental residual oxygen, in which the oxidation inhibit the stable formation of Ni silicide phase between electroless-plated Ni-P and silicon interface.

The pumping organ of blood-sucking female mosquitoes has a three-dimensional (3D) structure. However, conventional two-dimensional imaging methods are insufficient for visualizing the 3D structure in detail. Furthermore, their 3D imaging tasks are highly time consuming and sample preparation process requires elaborate skill. Among 3D imaging techniques, synchrotron X-ray microscopic computed tomography (SR-μCT) is especially suitable for small insects with opaque cuticles, such as mosquitoes. In this study, the 3D morphological structure of the pump system of a female mosquito was visualized using SR-μCT. Expandable volume capacities of two pump chambers were measured for several mosquito samples of similar size. To verify the cross-sectional images acquired by SR-μCT, complementary paraffin-sectioning data were compared. Microsc. Res. Tech. 75:1051–1058, 2012. © 2012 Wiley Periodicals, Inc.

Carboxylated single-walled carbon nanotubes (SWNTs) based chemicapacitive gas sensors were fabricated by AC dielectrophoretically aligning SWNTs across microfabricated gold electrodes with controlled density/device resistance. Two different sensing configurations (i.e., horizontal/in-plane and vertical/out-of-plane) were utilized to compare their sensing performance. Upon exposure to water vapor at room temperature, the response (R = [(C--C0)/C0] x 100%) increased with an increase in water vapor concentration similar to that of resistance response. In horizontal configuration, the response was increased with an increase in device resistance which might be attributed to preferentially alignment of semiconducting SWNTs during initial phase of alignment. However, the response was independent of device resistance in vertical/out-of-plane configuration which indicated that the sensing mechanism is based on the change of dielectric constant of gate and atmosphere.

Metal nanoparticles decorated single-walled carbon nanotubes (SWNTs) can lead to considerable enhancement in sensing performance towards different gas analytes, however the sensing mechanism was not clearly elucidated. The detailed sensing mechanism of hybrid gold-SWNT nanostructures toward hydrogen sulfide was investigated using field effect transistor (FET) transfer characteristics. At low H2S concentrations ( 100 ppbV), FET transfer characteristics show that the gold nanoparticles at the surface of SWNTs acted as nano-Schottky barriers to predominately modulate transconductance upon exposure to unfunctionalized SWNTs on gold electrodes which showed little or no response upon exposure. Although the sensitivity of Au/SWNT toward H2S was strongly dependent upon the size and number of gold nanoparticles, the sensing mechanism was independent of it.

We report the fabrication of ZnO quantum dots (QDs) embedded in SiO2 layers on c-Al2O3 and the production of ZnO QDs light emitting diodes (LEDs) by rf magnetron sputtering because ZnO QDs blue-shift the emission wavelength and enhance the emission efficiency due to the carrier localization effect. The PL intensity of ZnO QDs on n-type ZnO decays slower than that of n-type ZnO films as the temperature is increased due to the high activation energy (Ea) of ZnO QDs on n-type ZnO. The ZnO QD LED with p-type ZnO showed diode I-V characteristics (Vth = 3.4 V), band-edge emission at 375 nm, and a broad deep-level EL emission at 600 nm.

Thermoelectric Sb x Te y films were potentiostatically electrodeposited in aqueous nitric acid electrolyte solutions containing different concentrations of TeO2. Stoichiometric Sb x Te y films were obtained by applying a voltage of −0.15 V versus saturated calomel electrode (SCE) using a solution consisting of 2.4 mM TeO2, 0.8 mM Sb2O3, 33 mM tartaric acid, and 1 M HNO3. The nearly stoichiometric Sb2Te3 films had a rhombohedral structure, $$ R\bar{3}m $$ , with a preferred orientation along the (015) direction. The films had hole concentration of 5.8 × 1018/cm3 and exhibited mobility of 54.8 cm2/Vs. A more negative potential resulted in higher Sb content in the deposited Sb x Te y films. Furthermore, it was observed that the hole concentration and mobility decreased with increasingly negative deposition potential, and eventually showed insulating properties, possibly due to increased defect formation. The absolute value of the Seebeck coefficient of the as-deposited Sb2Te3 thin film at room temperature was 118 μV/K.

E-mail: ydkim91@skku.eduReceived November 30, 2010, Accepted January 8, 2011Key Words : NiO, Surface roughness, Solvent, Annealing, Inverted organic solar cellsOne of the clean alternative energy sources attractingparticular attention is solar cells, which can convert the solarlight directly to electricity.

Aspergillus is a common saprophytic fungi of the human airways and causes a broad spectrum of diseases, ranging from aspergilloma to invasive aspergillosis. There are few reports on mediastinal aspergilloma without any underlying pulmonary disease or immunocompromise. Herein, we report a case of mediastinal aspergilloma that we experienced and treated by thoracoscopic resection and oral antifungal medication.

The effect of patterned gallium oxide doped ZnO (GZO) layers on the electrical and the optical properties of light-emitting diodes (LEDs) are reported. GZO films were deposited by using pulsed laser deposition; then, the GZO layer was patterned by etching in a 1 wt.% HCl aqueous solution. The GaN-based LEDs with patterned GZO layers showed forward voltages similar to that of an LED with Ni/Au p-contact, which could be attributed to the fact that the ohmic contact to p-GaN was mainly formed by Ni/Au p-contact layers. The optical output power of the LED with patterned GZO layers exceeded that of an LED with a Ni/Au contact to p-GaN by over 20%. In addition, the peak emissions of the LEDs with patterned GZO layers showed less red-shift than the LEDs with Ni/Au layers, with an injection current more than 70 mA, due to more heat dissipation through the increased surface.

ZnO and Ga-doped ZnO thin films were electrodeposited as buffer layers between an indium tin oxide electrode and a photoactive layer for photo-induced electron transport and photo-induced hole blocking in inverted organic solar cells. Ga-doped ZnO thin films showed improved optical and electrical properties than the bare ZnO thin films, which also affected the performance of OCSs. The device with the Ga-doped ZnO buffer layer presented a higher Jsc value than that with bare ZnO which was caused by the higher transparency and carrier mobility of the deposited buffer layer. However, the Jsc value decreased when the gallium concentration in the films was increased, which induced the larger grain boundary and higher surface roughness and lead to carrier scattering and poor wettability between the buffer layers.

The objective of this study is to elucidate the feasibility of synchrotron X-ray micro CT as a non-destructive imaging method to visualize the three-dimensional morphological structures of biological and non-biological samples. The experiments were conducted in 7B2 X-ray micro CT beamline in Pohang Accelerate Laboratory (PAL). A rotational 3-axis stage was specially designed for scanning of test samples. Preliminary tests were performed for opaque samples including a mosquito head, a plant seed and gas diffusion layer (GDL) of polymer electrolyte fuel cell to verify the feasibility of the X-ray micro CT. It visualized clearly the internal structure of all the test samples, supporting its usefulness.

CdZnO thin films with near-band-edge (NBE) photoluminescence (PL) emission from 2.39 eV to 2.74 eV were grown by plasma-assisted molecular-beam epitaxy on c -plane sapphire substrates with 800 °C in situ annealing. CdZnO thin films evolve from pure wurtzite (wz) structure, to mixture of wz and rock-salt (rs) structures confirmed by X-ray diffraction studies. Rapid-thermo-annealing (RTA) was performed on in situ annealed CdZnO samples. Pure wz CdZnO shows insignificant NBE PL peak shift after RTA, while mixture structure CdZnO shows evident blue shifts due to phase change after annealing, indicating the rs phase CdZnO changes to wz phase CdZnO during RTA process.

The structural maintenance of chromosomes (SMC) family proteins are commonly found in the multiprotein complexes involved in chromosome organization, including chromosome condensation and sister chromatid cohesion. These proteins are characterized by forming a V-shaped homo- or heterodimeric structure with two long coiled-coil arms having two ATPase head domains at the distal ends. The hinge domain, located in the middle of the coiled coil, forms the dimer interface. In addition to being the dimerization module, SMC hinges appear to play other roles, including the gateway function for DNA entry into the cohesin complex. Herein, we report the homodimeric structure of the hinge domain of Escherichia coli MukB, which forms a prokaryotic condensin complex with two non-SMC subunits, MukE and MukF. In contrast with SMC hinge of Thermotoga maritima which has a sizable central hole at the dimer interface, MukB hinge forms a constricted dimer interface lacking a hole. Under our assay conditions, MukB hinge does not interact with DNA in accordance with the absence of a notable positively charged surface patch. The function of MukB hinge appears to be limited to dimerization of two copies of MukB molecules. Proteins 2010. © 2009 Wiley-Liss, Inc.

The electrical transport and NH3 sensing properties of randomly oriented and aligned SWNT networks were presented and discussed. The results indicate that aligned SWNT-FETs have better FET characteristics due to the reduced number of interconnected nodes. This was particularly true as the resistance of the devices increased. Gated electrical breakdown was implemented to selectively remove metallic (m-) SWNTs, thereby reducing scattering centers. This technique provided significant improvements in FET characteristics resulting in greater on/off ratio (e.g. 10 4 ). AC dielectrophoretic alignment followed by selective electrical breakdown of m-SWNTs can significantly enhance the semiconducting properties of SWNT networks which resulted in highly sensitive sensors.

All metazoan guts are in permanent contact with the microbial realm. However, understanding of the exact mechanisms by which the strength of gut immune responses is regulated to achieve gut-microbe mutualism is far from complete. Here we identify a signaling network composed of complex positive and negative mechanisms that controlled the expression and activity of dual oxidase (DUOX), which 'fine tuned' the production of microbicidal reactive oxygen species depending on whether the gut encountered infectious or commensal microbes. Genetic analyses demonstrated that negative and positive regulation of DUOX was required for normal host survival in response to colonization with commensal and infectious microbes, respectively. Thus, the coordinated regulation of DUOX enables the host to achieve gut-microbe homeostasis by efficiently combating infection while tolerating commensal microbes.

Condensin complexes are the key mediators of chromosome condensation. The MukB–MukE–MukF complex is a bacterial condensin, in which the MukB subunit forms a V-shaped dimeric structure with two ATPase head domains. MukE and MukF together form a tight complex, which binds to the MukB head via the C-terminal winged-helix domain (C-WHD) of MukF. One of the two bound C-WHDs of MukF is forced to detach from two ATP-bound, engaged MukB heads, and this detachment reaction depends on the MukF flexible linker preceding the C-WHD. Whereas MukB is known to focally localize at particular positions in cells by an unknown mechanism, mukE- or mukF-null mutation causes MukB to become dispersed in cells. Here, we report that mutations in MukF causing a defect in the detachment reaction interfere with the focal localization of MukB, and that the dispersed distribution of MukB in cells correlates directly with defects in cell growth and division. The data strongly suggest that the MukB–MukE–MukF condensin forms huge clusters through the ATP-dependent detachment reaction, and this cluster formation is critical for chromosome condensation by this machinery. We also show that the MukF flexible linker is involved in the dimerization and ATPase activity of the MukB head. Structured digital abstract • MINT-7216106: mukBhd (uniprotkb:P22523), mukF (uniprotkb:P60293) and mukE (uniprotkb:P22524) physically interact (MI:0915) by blue native page (MI:0276)

Chromosomes are condensed in all forms of life. SMC-based condensins are the key mediators in this process, but their molecular mechanisms remain elusive. Two different condensin complexes have been identified in prokaryotic organisms: MukB-MukE-MukF and SMC-ScpA-ScpB. This review focuses on comparison between the two machineries based on structural, biochemical and other related information in the light of their structure and function.

ZnO thin films were grown on r-plane sapphire substrates using electron cyclotron resonance (ECR) plasma-assisted molecular-beam epitaxy. The effect of the oxygen ECR plasma power on the growth rate, structural, electrical, and optical properties of the ZnO thin films were studied. It was found that larger ECR power leads to higher growth rate, better crystallinity, lower electron carrier concentration, larger resistivity, and smaller density of non-radiative luminescence centers in the ZnO thin films.

The aim of this work was to obtain uniform and well-dispersed spherical silver nanoparticles using statistical design of experiments. For the purpose, we have performed the experiments based on the statistical design regarding some key factors involved in a general chemical reduction method. The nanoparticles prepared were characterized by SEM, TEM and UV–vis absorbance for particle size, distribution, aggregation and anisotropy. The data obtained were analyzed and optimized using a statistical software. The design of experiments using quantified data enabled us to understand effects of factors and interactions between them. The principal properties of produced nanoparticles were dominated by not only individual one or two main factors but also interactions between factors. The appropriate combination of the factors led to synthesis of small, narrow-distributed and non-aggregated silver nanoparticles of about 30 nm with approximately 10% standard deviation.

Accurate forecasting of pest density is essential for effective pest management. In this study, a simple image processing system that automatically estimated the density of whiteflies on sticky traps was developed. The estimated densities of samples in a laboratory and a greenhouse were in accordance with the actual values. The detection system was especially efficient when the whitefly densities were at medium to high levels, however, the development of identification algorithms and more appropriate collection methods may improve the image processing system. Taken together, the results of this study indicate that the image processing system described here may be useful for evaluating the population dynamics.

Surface manipulation can affect both the efficiency and reliability of metal oxide photoelectrodes through the adjustment of the properties of the interface between the electrodes and the electrolyte.

ZnO is attracting considerable attention for its possible application to light-emitting sources due to its advantages over GaN. We review the recent progress in the growth of ZnO epitaxial films, doping control, device fabrication processes including etching and ohmic contact formation, and finally the prospects for fabrication and characteristics of ZnO light-emitting diodes.

Recognition of lysine-type peptidoglycan by peptidoglycan recognition protein (PGRP)-SA provokes the activation of the Toll and prophenoloxidase pathways. Here we reveal that a soluble fragment of lysine-type peptidoglycan, a long glycan chain with short stem peptides, is a potent activator of the Drosophila Toll pathway and the prophenoloxidase activation cascade in the beetle Tenebrio molitor . Using this peptidoglycan fragment, we present biochemical evidence that clustering of PGRP-SA molecules on the peptidoglycan is required for the activation of the prophenoloxidase cascade. We subsequently highlight that the lysozyme-mediated partial digestion of highly cross-linked lysine-type peptidoglycan dramatically increases the binding of PGRP-SA, presumably by inducing clustering of PGRP-SA, which then recruits the Gram-negative bacteria-binding protein 1 homologue and a modular serine protease containing low-density lipoprotein and complement control protein domains. The crucial role of lysozyme in the prophenoloxidase activation cascade is further confirmed in vivo by using a lysozyme inhibitor. Taken together, we propose a model whereby lysozyme presents a processed form of lysine-type peptidoglycan for clustering of PGRP-SA that recruits Gram-negative bacteria-binding protein 1 and the modular serine protease, which leads to the activation of both the Toll and prophenoloxidase pathways.

The hydrogen gas-sensing properties have been investigated of two types of thermochemical hydrogen (TCH) sensors composed of thermoelectric layers based on chalcogenide nanowire arrays and anodic aluminum oxide (AAO) templates. The monomorphic-type TCH sensor, which had only Bi2Te3 nanowire arrays, showed an output signal of 23.7 ?V in response to 5 vol% hydrogen gas at room temperature, whereas an output signal of 215 ?V was obtained from an n?p junction-type TCH sensor made of connected Bi2Te3 and Sb2Te3 nanowire arrays in an AAO template. Despite its small deposition area, the output signal of the n?p sensor was more than nine times that of the monomorphic sensor. This observation can be explained by the difference in electrical connections (parallel and serial conversions) in the TCH sensor between each type of nanowire array. Also, our n?p sensor had a wide detection range for hydrogen gas (from 400 ppm to 45 vol%) and a fast response time of 1.3 s at room temperature without requiring external power.

to improve the structural properties of n- and p-type ZnO compared to previous studies. [7] In addition, a thermal annealing process was carried out to activate the phosphorus dopants in p-type ZnO and improve the electrical and optical properties of the ZnO layers. The LED showed excellent current-rectifying behavior with a threshold voltage of 3.2 V and an EL emission peak at 380 nm at room temperature. The UV EL emission spectrum was in good agreement with the room-temperature photoluminescence (PL) spectrum of the p-type ZnO used in the LED. Furthermore, the near-bandedge emission was increased and the deep-level emission was decreased when (Mg,Zn)O alloy layers were introduced as energy barrier layers between n-type and p-type ZnO films to confine the carrier recombination process to the high-quality n-type ZnO film. A schematic diagram of the p–n homojunction ZnO LED is shown in Figure 1. The gallium-doped n-type ZnO with a thickness of 1.5 lm was grown on a c-Al2O3 substrate. It

The maskless selective wet etching of p-GaN layer with KOH in ethylene glycol (KE) and H3PO4/H2SO4 (HH) acids was developed for the highly efficient light-emitting diodes (LEDs). The p-GaN surfaces textured by the selective wet etching process without using etch mask showed hexagonal and stripe shapes in the KE and HH solutions, respectively. The current-voltage (I-V) characteristics of the LED textured by KE and HH solutions showed improved electrical properties compared to the non-etched LED. This result could be attributed to a reduced contact resistance due to an increased contact area between the metal electrode and p-GaN layer. In addition, the light-output power of the LED textured by KE and HH solutions was improved by 29.4% and 36.8% relative to that of the non-etched LED. This result was attributed to the increase in probability of escaping photons from the LED and the reduction of surface defects by the maskless selective wet etching process. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Thoracic extramedullary hematopoiesis (EMH) is a rare disease entity that is usually associated with hematologic disorders, such as myelodysplastic or hemolytic disease. Because thoracic EMH is usually encountered as a mass during radiologic examinations, it should be differentiated from posterior mediastinal neurogenic tumors. Here, the authors report a case of EMH associated with hereditary spherocytosis. The patient underwent a complete excision by thoracoscopic surgery to differentiate it from other mediastinal tumors.

The substitutional doping approach has been shown to be an effective strategy to improve ZT of Bi2Te3-based thermoelectric raw materials. We herein report the Fe-doping effects on electronic and thermal transport properties of polycrystalline bulks of p-type Bi0.48Sb1.52Te3. After a small amount of Fe-doping on Bi/Sb-sites, the power factor could be enhanced due to the optimization of carrier concentration. Additionally, lattice thermal conductivity was reduced by the intensified point-defect phonon scattering originating from the mass difference between the host atoms (Bi/Sb) and dopants (Fe). An enhanced ZT of 1.09 at 300 K was obtained in 1.0 at% Fe-doped Bi0.48Sb1.52Te3 by these synergetic effects.

Thiolase is the first enzyme catalysing the condensation of two acetyl-coenzyme A (CoA) molecules to form acetoacetyl-CoA in a dedicated pathway towards the biosynthesis of n-butanol, an important solvent and biofuel. Here we elucidate the crystal structure of Clostridium acetobutylicum thiolase (CaTHL) in its reduced/oxidized states. CaTHL, unlike those from other aerobic bacteria such as Escherichia coli and Zoogloea ramegera, is regulated by the redox-switch modulation through reversible disulfide bond formation between two catalytic cysteine residues, Cys88 and Cys378. When CaTHL is overexpressed in wild-type C. acetobutylicum, butanol production is reduced due to the disturbance of acidogenic to solventogenic shift. The CaTHLV77Q/N153Y/A286K mutant, which is not able to form disulfide bonds, exhibits higher activity than wild-type CaTHL, and enhances butanol production upon overexpression. On the basis of these results, we suggest that CaTHL functions as a key enzyme in the regulation of the main metabolism of C. acetobutylicum through a redox-switch regulatory mechanism., n-Butanol is a valuable biofuel that can be produced industrially by bacterial fermentation. Here the authors uncover a redox-switch within Clostridium acetobutylicum's thiolase—a key enzyme involved in n-butanol biosynthesis—that controls the rate of fermentative butanol production.

Pine cones fold their scales when it rains to prevent seeds from short-distance dispersal. Given that the scales of pine cones consist of nothing but dead cells, this folding motion is evidently related to structural changes. In this study, the structural characteristics of pine cones are studied on micro-/macro-scale using various imaging instruments. Raindrops fall along the outer scales to the three layers (bract scales, fibers and innermost lignified structure) of inner pine cones. However, not all the layers but only the bract scales get wet and then, most raindrops move to the inner scales. These systems reduce the amount of water used and minimize the time spent on structural changes. The result shows that the pine cones have structural advantages that could influence the efficient motion of pine cones. This study provides new insights to understand the motion of pine cones and would be used to design a novel water transport system.

We show that a graphitic carbon interfacial layer, derived from C70 by annealing at 500 °C, results in a significant increase in the attainable photocurrent of a photoelectrochemical cell that contains a WO3 -functionalized fluorine-doped tin oxide (FTO) photoanode. Time-resolved photoluminescence spectroscopy, photoconductive atomic force microscopy, Hall measurements, and electrochemical impedance spectroscopy show that the increase in photocurrent is the result of fast and selective electron transport from optically excited WO3 through the graphitic carbon interfacial layer to the FTO-coated glass electrode. Thus the energy efficiency of perspective solar-to-fuel devices can be improved by modification of the interface of semiconductors and conducting substrate electrodes by using graphitized fullerene derivatives.

Synchrotron X-ray imaging technique has been used to investigate biofluid flows in a non-destructive manner. This study aims to investigate the feasibility of the X-ray PIV technique with CO2 microbubbles as flow tracer for measurement of pulsatile blood flows under in vivo conditions. The traceability of CO2 microbubbles in a pulsatile flow was demonstrated through in vitro experiment. A rat extracorporeal bypass loop was used by connecting a tube between the abdominal aorta and jugular vein of a rat to obtain hemodynamic information of actual pulsatile blood flows without changing the hemorheological properties. The decrease in image contrast of the surrounding tissue was also investigated for in vivo applications of the proposed technique. This technique could be used to accurately measure whole velocity field information of real pulsatile blood flows and has strong potential for hemodynamic diagnosis of cardiovascular diseases.

The thermoelectric (TE) energy-conversion efficiency of TE materials has been steadily improved over recent decades. This efficiency is expressed in terms of a dimensionless number zT = S2σT/k, which is simply referred to as the figure-of-merit, where S is the Seebeck coefficient, σ is the electrical conductivity, k is the thermal conductivity, and T is the absolute temperature. Limited success at increasing zT has been achieved by focusing on k reduction, which is thought to increase phonon scattering by incorporating complex lattice structures, such as superlattices, heterostructures, and nanocomposites, into the material. For some materials, k can be reduced to a minimum by placing the substance in an amorphous state; however, this behavior is typically associated with a substantial decrease in the charge carrier mobility and, therefore, in σ. This strong interdependence among the key parameters of zT has delayed the release of new high-zT TE devices for use in industry. Therefore, this study adopts a different approach, which focuses on controlling the mechanisms and processes that tend to de-couple the key parameters and maximize the zT numerator. Particular attention is paid to mechanisms that optimize the power factor (P.F.), which is equal to σS2. In this work, we tailored nanocomposite embedded structure in Bi-Te and Sb-Te based films, resulting in allowed the realization of intriguing TE performance based on interfacial energy-barrier scattering. The TE performance of nanocrystalline films is optimized by tailoring the Vb employed in the energy-filtering mechanisms in two positions: 1) at the grain boundaries of the single-phase nanocrystalline films and 2) at the interfaces of the hetero-nanocomposites. More details will be presented

Indium is an essential element for the fabrication of transparent conductive oxide (TCO) materials. However, it is very rare element and is obtained as a byproduct of zinc metal refining. Moreover, its recycling rate is less than 1%. This provokes the need to recycle indium from its end products. Indium and tin (Sn) are especially well suited for molten salt electrolysis because of their low melting points. In this paper, reduction processes on molybdenum electrode at 500oC in molten LiCl–KCl eutectic (55.7-44.3 mol %) containing varying amount of InCl3 was studied by Cyclic Voltammetry (CV) and Chronopotentiometry (CP). In-Sn alloy was used as raw material. Thermodynamic calculations showed poor stability of InCl3 with metal based crucibles. So, Al2O3 crucible was utilized for the experiments. Concentration of InCl3 was changed from 1 wt% to 3 wt% and it was found that the reduction of indium ions take place by a two-step electrochemical reaction: In3+/In+ and In+/Ino at the potentials of 0.78 and 0.24 V versus Ag/AgCl. Number of transferred electrons and diffusion coefficient of In+3 ion species in molten salt with varying InCl3 content was estimated with the help of CV measurements. However, at 500oC, InCl3 shows chemical reactivity with Sn metal according to the following reaction: InCl3 + 1.5Sn → 1.5SnCl2 + In. This problem was overcome by shifting the molten chloride system to molten fluoride system (LiF-KF-InF3) as fluoride based salts shows high chemical stability with metals. As a result of electrorefining, In-Sn alloy was recycled into pure indium with low levels of impurities.

Zebrafish has been used as a powerful model system in biological and biomedical studies studying development and diseases. Comparative, functional, and developmental studies on zebrafish morphology require precise visualization of 3D morphological structures. Few methods that can visualize whole-volume of zebrafish tissues are available because optical bio-imaging methods are limited by pigmentation and hard tissues. To overcome these limitations, the 3D microstructures of a hypercholesterolemic zebrafish model are visualized using synchrotron X-ray micro-computed tomography (SR-μCT). The model spatial resolution ranged from sub- to several microns. The microstructures of various zebrafish organs are observed by combining high-contrast staining (osmium tetroxide and uranyl acetate) and embedding a protocol to enhance the image contrast of soft tissues. Furthermore, blood vessels are identified using a barium sulfate injection technique. The internal organs and cells, such as liver, intestine, oocytes, and adipocytes, of a hypercholesterolemic zebrafish are compared with those of normal organs and cells. The SR-μCT is useful for understanding the pathogenesis of circulatory vascular diseases by detecting the modifications in the 3D morphological structures of the whole body of the zebrafish. This bio-imaging technique can be readily used to study other disease models.

Three-dimensional hybrid nanostructures (i.e., Te “nanobranches” on a Si “nanotrunk” or Te “nanoleaves” on a Si “nanotrunk”) were synthesized by combining the gold-assisted chemical etching of Si to form Si “nanotrunks” and the galvanic displacement of Si to form Te “nanobranches” or “nanoleaves.” By adjusting the composition of the electrolyte used for the galvanic displacement reaction, the shape of the Te nanostructures could be changed from nanoleaves to nanobranches. The Si nanotrunks with Te nanobranches showed stronger luminescent emission in the visible region, with their Raman spectrum having a higher wave number, owing to their grain size being larger. This suggested that the optical and photoelectrochemical properties of Te–Si hybrid nanostructures depend on their shape and size. Using this approach, it should be possible to fabricate various hierarchical nanostructures for use in photoelectronic and photoelectrochemical devices.

Four-dimensional imaging, which indicates imaging in three spatial dimensions as a function of time, provides useful evidence to investigate the interactions of rising bubbles. However, this has been largely unexplored for microbubbles, mostly due to problems associated with strong light scattering and shallow depth of field in optical imaging. Here, tracking x-ray microtomography is used to visualize rising microbubbles in four dimensions. Bubbles are tracked by moving the cell to account for their rise velocity. The sizes, shapes, time-dependent positions, and velocities of individual rising microbubbles are clearly identified, despite substantial overlaps between bubbles in the field of view. Our tracking x-ray microtomography affords opportunities for understanding bubble-bubble (or particle) interactions at microscales - important in various fields such as microfluidics, biomechanics, and floatation.

The electrochemical and structural properties of cobalt oxide films which are deposited at different sputtering gas-ratios of O2/(Ar+O2) are investigated. In order to examine the electrochemical properties of the as-deposited films, all solid-state thin-film supercapacitors (TFSCs) are fabricated. There consist of Co3O4 electrodes and an amorphous LiPON thin-film electrolyte. It is shown that the capacitance behaviour of the Co3O4/LiPON/Co3O4 TFSCs is similar to bulk-type supercapacitor behaviour. It is further shown that the electrochemical behaviour of the TFSCs is dependent on the sputtering gas-ratios. The gas-ratio dependence of the capacitance of the oxide electrode films is discussed based on X-ray diffraction (XRD) and electrical results for the Co3O4 films.

The selective wet etching of a p-GaN layer by using a solution of KOH in ethylene glycol (KE) was studied to enhance the optical and electrical performance of the GaN-based light-emitting diodes (LEDs). The surface of the p-GaN, which was selectively etched in the KE solution, showed hexagonal-shaped etch pits. The light-output power of etched LEDs was improved by 29.4% compared to that of the nonetched LED. This improvement was attributed to the increase in the probability of photons to escape due to the increased surface area of textured surface and the reduction in contact resistance of the ohmic layer resulting from the increased contact area and hole concentration on the textured p-GaN. The reverse leakage current of the LED was also greatly decreased due to the surface passivation and the removal of defective regions from the p-GaN.

We investigated the ZnO based ohmic scheme as a transparent and low resistance contact layer on p-GaN. ZnO based contact yielded a very low specific contact resistance of 3.6 × 10–5 Ω·cm2 when annealed at 500 °C for 1 min in a nitrogen ambient, and the transparency was above 80% at wavelengths of 450 nm. In addition, we fabricated an InGaN/GaN MQW LED with a dimension of 300 × 300 µm using a transparent ZnO based ohmic contact as a current spreading layer for p-GaN in order to increase the optical output power. The GaN LED with a transparent ZnO based ohmic contact showed a decrease in the forward voltage by 0.15 V under a nominal forward current of 20 mA compared to GaN LED with Ni/Au ohmic contact. In addition, the light output power of LED with ZnO based contact was increased by 38.9% at 20 mA. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)