bluuebunny/crossref_metadata_2025 huggingface dataset:
Visible Light Responsive Titanium Dioxide Photocatalysts Prepared by Ultraviolet Irradiation
Authors: Nishizawa Kaori , Watanabe Eiji , Inukai Keiichi , Maeda Masaki
Published: August 2011

Titanium dioxide photocatalyst films were prepared by dip-coating method using titanium dioxide sol solution in order to research the H2O addition effect on the photocatalytic activities. The sol solution was prepared with titanium tetra-isopropoxide, urea and 2-methoxyethanol, then irradiated ultraviolet light and added distilled H2O. The substrates for the dip-coating were fused silica plates and as-prepared films were dried at 100 °C then annealed at 650 °C. The films prepared by these methods showed visible light absorption in wavelengths longer than 380 nm and accelerated photodegradation of methylene blue by visible light irradiation. Furthermore, the photocatalytic activities of these films were depending on the H2O additions to the sol solution.
Fabrication and Properties of Carbon Fibre-Basalt Fibre/Epoxy Resin Composites
Authors: Jin Hai Yun , Feng Da Wei , Li Wen Zhao , Ren Hong Guang , Su Ying , He Bo , Zhou Ze , Peng Zong Ren , Wang Chuan Bin
Published: August 2011

Different compositions of carbon fibre (Cf) - basalt fibre (Bf)/ Epoxy Resin (EP) Composites were fabricated. The mechanical properties were investigated and the microstructure was observed by SEM. The results showed that, the mechanical properties would be improved when suitable content (10-20vol.% of total fibre) of basalt fibre added into carbon fibre/ epoxy composites. It was because that elasticity modulus of basalt fibre was larger than carbon fibre, and for existing of more hydroxyl groups and other active groups, the bonding between basalt fibre and epoxy resin was also better than the bonding between carbon fibre and epoxy resin.
Improved Photoelectrode of Dye-Sensitized Solar Cell Using a ZnO/Zn2TiO4
Authors: Koonnasoot Warut , Gardchareon Atcharawan , Choopun Supab , Wongratanaphisan Duangmanee
Published: August 2011

Zinc titanate nanostructures were prepared by oxidation reaction technique. Here Zn mixed with 0, 10, 20 and 30 mol% of TiO2powder was screened on alumina and FTO substrate, and then sintered at 400–600°C for 12 h under normal atmosphere. Through a detailed field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), and x-ray diffraction (XRD) indicated that the nanostructures exhibited belt-like shapes of Zn2TiO4phase. Moreover, the belt-like nanostructures of the synthesized Zn2TiO4were studied in terms of optical properties by the UV-vis spectroscopy (UV-vis) to obtain band gap energy (Eg). The results showed that the Eggap energy ranged from 3.57 eV to 3.63 eV as the mol% of TiO2increased. In addition to the characterization of the nanobelts, the synthesized Zn2TiO4 nanostructures were applied as a bilayer semiconductor electrode in ZnO-based dye-sensitized solar cell (DSSC). It was shown that the use of Zn2TiO4nanostructure with 10 mol% TiO2in the ZnO/Zn2TiO4electrode components of the DSSC revealed the highest obtainable efficiency.
Influence of Ring Length on Electric Field Distribution in CdZnTe Frisch-Ring Detector
Authors: Ren Jie , Fu Li , Meng Ling Bao
Published: August 2011

The CdZnTe (CZT) devices with various screening depth in dimensions 3×3×6mm3 were fabricated. The influence of Ring length (screening depth) and length of crystal on the electric field distribution in CZT devices has been explored by finite element method. The results indicated that ring length (screening depth) plays an important role on the detecting performance of CZT Frisch-ring devices. Longer screening depth gives rise to an electric field which is compressed more greatly. Measured spectra indicated that extreme compressed electric field could reduce detecting resolution. A FWHM energy resolution of approximately 3.71% at 662 keV was obtained for a device with dimensions 3×3×6mm3 and 4.8mm screening depth.
Effects of Ca2+ Concentration on Calcium Carbonate Crystallization in Lignin Solution System
Authors: Zhu Wen Kun , Luo Xue Gang , Lin Xiao Yan , He Pan
Published: August 2011

The calcium carbonate crystallization was controlled by Ca2+concentrations, under the system of lignin solution with concentration of 10 g / L. Its morphology, structure and thermal decomposition were characterized by FT-IR, SEM, XRD and TG. Results showed that in lignin solution system, concentration of Ca2+had significant effects on the crystallized morphology, orientation and crystallinity of calcium carbonate. Calcium carbonate crystal under low Ca2+concentration had more uniform size while under high Ca2+concentration which tended to form various sizes with more complete crystallization. The calcium carbonate crystals were all calcite calcium carbonate, which formed under different Ca2+concentrations.
Mechanical Properties of Dysprosia (Dy2O3) Added Al2O3 ZrO2 HA Composite
Authors: Kim Hyung Suk , Lee Hyun Hwi , Kim Seung Ho , Cho Sung Hun , Lee Soo Wohn
Published: August 2011

Alumina (Al2O3)-zirconia (ZrO2)-hydroxyapatite (HA) composite is used as biomaterials. Biomaterials must be bio-compatible to the body and should have excellent mechanical and tribological properties. 1 wt.% of rare earth oxide (Dy2O3) was added to the basic composition of composite Al2O3-ZrO2(15wt.%)-HA(1wt.%). The powder mixture was hot-pressed at 1300°C in Ar gas environment under 30 MPa pressure for densification sintering. The microstructural analysis, phase transformation, surface morphology and mechanical properties like hardness, fracture toughness, mechanical strength of the composite were observed and evaluated by SEM , XRD, Vickers hardness, etc. The results demonstrated that the addition of 1 wt.% dysprosia has increased the mechanical properties of composite.
TEM Analysis on Nanovoid Formation in Annealed Amorphous Oxides
Authors: Nakamura Ryusuke , Shudo Takehiro , Hirata Akihiko , Ishimaru Manabu , Nakajima Hideo
Published: August 2011

Formation behavior of nanovoids during the annealing of amorphous Al2O3 and WO3 was studied by transmission electron microscopy. The density and size of the voids in Al2O3 and WO3 increase with increasing annealing temperature from 973 to 1123 K and from 573 to 673 K, respectively. It is suggested that the formation of nanovoids during annealing is attributed to the large difference in density between as-deposited amorphous and crystalline oxides.
Effect of X-Ray Irradiation on the Current of P-N Diode
Authors: Srithanachai Itsara , Ueamanapong Surada , Rujanapich Poopol , Poyai Amporn , Niemcharoen Surasak , Titiroongruang Wisut
Published: August 2011

An effect induced by x-ray irradiation on Boron-doped crystalline Si at room temperature was closely investigated in this paper. Irradiation of X-ray energy of 40, 55 and 70keV has been performed on P-N junction diodes fabricated at Thai Microelectronics Center. Minority carrier life time of the device has been calculated before and after irradiation for comparison. The results show no significant change on the value between exposed and unexposed device. Therefore, any permanent lattice modified or any defects caused by X-ray in the device bulk seem to be unconfirmed in this range of energy. However, from this study, X-ray irradiation still effects on electrical characteristics of the diodes. Current-voltage (I-V) measurement has been carried out to study characteristic variation of the device. Biasing of the device was performed from -10 to 1 V and, after the exposure, the leakage current was obviously decreased by 25% and forward current was dramatically increased by 3 order of magnitude related to increment of X-ray energy.
Enhancement of Sensor Response by Au Nanoparticles Doping on ZnO Tetrapod Sensor
Authors: Bhoomanee Chawalit , Gardchareon Atcharawan , Hongsith Niyom , Choopun Supab , Wongratanaphisan Duangmanee
Published: August 2011

Zinc oxide tetrapods (T-ZnO) were synthesized using thermal oxidation technique from Zn powders mixed with hydrogen per oxide (H2O2). Through a detailed field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), and x-ray diffraction (XRD) showed that the T-ZnO exhibited single crystalline hexagonal wurtzite structure. The leg tip of the T-ZnO was about 8.17±1.17 µm in length and 47.80 nm in diameter. The ethanol sensors, based on the T-ZnO and the T-ZnO doped with Au nanoparticles (Au/T-ZnO), were fabricated and investigated for the ethanol sensing properties. The ethanol sensor response of the T-ZnO and the Au/T-ZnO sensors was tested at the operating temperature of 260-360°C with the ethanol concentration of 50, 100, 500, and 1000 ppm. The results showed that the Au/T-ZnO sensors exhibited exceptionally higher sensitivity than the pure T-ZnO sensors for entire ethanol concentration with optimum temperature of 340°C and 320°C, respectively. This enhancement can be explained in terms of the electron concentration of sensor in air, n0 and the reaction rate constant, kEth between the adsorbed oxygen species and the ethanol vapor due to the increase of effective surface for adsorption of ethanol on the surface. With an excellent catalytic ability, the Au nanoparticles doping on the T-ZnO sensors would result in higher reaction rate constant than the undoped T-ZnO sensors.
Geometrical Dependency of Wiggler Characteristics in the Miniaturized Free Electron Laser Module
Authors: Kim Young Chul , Ahn Seong Joon , Park Chul Geun , Ahn Seung Joon
Published: August 2011

The characteristics of the e-beam have been investigated according to the various parameters of the wiggler in a miniaturized free electron laser (FEL) module by using 3-dimensional (3D) simulations. The e-beam emerging from the electron emitter was made parallel by applying a static bias to the middle electrode of the electron lens set. It was found that the width of the wiggler electrodes had great effect on the e-beam trajectory inside the wiggler.
Fabrication and Precise Alignment of Electron Lenses in the Microcolumn Using the Laser Diffraction Pattern
Authors: Ahn Seong Joon , Kim Ho Seob , Ahn Seung Joon
Published: August 2011

The quality of electron lenses and precision of their alignment are very important factors that determine the resolution of the microcolumn. In this work, we have fabricated the quality electron lenses using the semiconductor processing technologies and checked their circular shapes by using the laser diffraction pattern. The observed diffraction pattern by naked eyes was the circular Airy disk and the measured eccentricity of the lens aperture was found to be less than 0.02. We have also made precise alignment of the electron lenses by illuminating the laser beam through the roughly aligned electron lenses and adjusting the electron lenses while monitoring the diffraction pattern formed by the diffracted laser light from the lens apertures. This new method can replace the conventional alignment method where the expensive equipment like the aligner or the STM is required. We have also found the misalignment limit by measuring the e-beam current that came out from the microcolumn.
Effect of Membrane Material Properties on Efficiency of Membrane Distillation
Authors: Kim Hwan , Choi June Seok , Lee Sang Ho
Published: August 2011

Membrane distillation (MD) integrates membrane technology with evaporation process to produce fresh water from seawater or contaminated water. In this study, we investigated the effect of membrane materials on the efficiency of membrane distillation process. Flat sheet hydrophobic membranes (PVDF, PTFE) with different characterizes were chosen as well as hollow fiber membranes (PE). Laboratory-scale systems were developed for initial screening of various membranes. The performance of the membrane was analyzed in terms of water permeability and salt rejection. Synthetic seawater (TDS = 35,000 mg/L) was used for the lab-scale tests. A simple model to analyze the transport of water through MD membranes was developed to interpret experimental results. In addition, long-term performances of the membranes were compared to examine the stability of membrane materials and fouling tendency using real seawater. Based on the lab-scale experiments, techniques to improve the performance of the membranes were examined by applying physical and chemical modification.
Influences of Atomizing Pressure on Properties and Microstructure at Brazed Joint of Lead-Free Solder Powder
Authors: Xu Tian Han , Jin Hai Yun , Zhao Mai Qun , Wang Dang Hui
Published: August 2011

The effects of the atomizing pressure on the microstructures and properties of the lead-free solder powder by the supersonic atomizer method were investigated. The microstructures of the brazed joint of solder paste were also observed. The results showed that with increasing atomizing pressures from 0.4 to 0.7 MPa, the powder particles are refined significantly and the effective atomization efficiency increases rapidly, but the oxygen content slightly rises. When the atomizing pressures increases from 0.7 to 0.9 MPa, the effective atomization efficiency only increases slightly, meanwhile both sphericity and roughness of the powder deteriorate. The atomized powder exhibits high effective atomizing efficiency, uniform size distribution, good sphericity and smooth surface when the atomizing pressure is 0.7 MPa. The diffusion layer brazed welded by Sn3Ag2.8Cu paste with Cu substrate is thicker and more irregular than that of by Sn37Pb paste.
Analysis of Fiber Filter Media after 6 Years of Use as a First Flush Filter
Authors: Kim Ree Ho , Lee Jung Hun , Lee Sang Ho , Kim Hana
Published: August 2011

Pollutants in rainwater often cause problems such as non-point source pollutant and deterioration of collected water quality in rainwater harvesting systems. Fiber filter media have been developed to resolve these problems by removing pollutants in rainwater by filtration and ion-exchange mechanisms. They have been also successfully applied for the treatment of first-flush rainwater. However, little information is available on the long-term efficiency and the lifetime of the fiber filter media. In this study, new and used fiber filter media were compared in terms of their filterability and ion-exchange capability. The used filter media samples were taken from a first flush filter in a rainwater harvesting system located in an elementary school in Kyonggi-Do. They were used from 2005 to 2010 without any replacement or cleaning. Water quality parameters of an inflow and outflow in the first flush filter were analyzed to quantify the on-site treatment efficiency of the used media. It was shown that the turbidity was removed by approximately 60% and COD was partly removed. The removal efficiency of particles by the used media was similar to that by the new media. Nevertheless, the removal efficiencies of nitrogen and phosphorous by the used media were substantially reduced when compared with the new media. This suggests that the fiber filter media should be periodically replaced to maintain high removals of nutrients. On the other hand, they can be used for more than 6 years if their primary purpose is to removal particles.
Application of Acid Modified CuO/Al2O3 Nanostructured Catalysts and its Cytotoxicity Assessment for Enhanced CH4-SCR Performance
Authors: Hung Chang Mao
Published: August 2011

The effect of treatment with different inorganic acids (HNO3, CH3COOH, and H3PO4) on the activity of CuO/γ-Al2O3 nanostructured catalysts selective catalytic reduction of NO by hydrocarbons (HC-SCR) using CH4as a reducing agent in a tubular fixed-bed reactor (TFBR) at temperatures from 623-1023 K in the presence of oxygen was studied. A CuO/γ-Al2O3 nanostructured catalyst was prepared by incipient wetness impregnation approach of copper nitrateand γ-alumina support. The catalysts were characterized using AEM and XRD. The experimental results show that the support γ-alumina with a 6 N HNO3solution at the calcinations temperature of 873 K obvious promoting effects on the higher activity due to greater acidity of the transforming NO reaction over a CuO/γ-Al2O3nanostructured catalyst, because the acidic pretreatment provides the acidic sites for the catalyst surface and improved the dispersion of copper species and the reactivity over the catalyst reaction system with NO-CH4-O2. Further, cell cytotoxicity and the percentage cell survival was determined by using MTS assay on human fetal lung tissue cell (MRC-5). The experimental results show that the nanoscale CuO/γ-Al2O3catalyst only minor cause cytotoxicity effect in cultured human cells.
Special Application Magnetorheological Valve Numerical and Experimental Analysis
Authors: Kciuk Sławomir , Martynowicz Paweł
Published: August 2011

The paper addresses analytical, numerical and experimental aspects of the design of magnetorheological (MR) fluid valve. Magnetic flux in valve’s cross-section is analysed with the help of finite element method (FEM) software. Based on the magnetic field intensity distribution within valve’s MR fluid annular gap, simulation model of the shock absorber equipped with newly designed MR valves is developed. Prototypes of MR valve are built and embedded in the stationary barrier of the rotary shock absorber, instead of standard, passive check valves. Simulation and preliminary experimental results comprising resistance force values as a function of angular displacement and angular velocity are presented.
Model of a Squeeze Mode Magnetorheological Mount
Authors: Gołdasz Janusz , Sapiński Bogdan
Published: August 2011

Recent advances in the research of magnetorheological (MR) fluid based devices have indicated the opportunities for squeeze mode devices using the smart fluids. The mode seems suitable for small amplitude and high force applications. Therefore, it is of a research and engineering interest to explore the model of a controlled squeeze mode MR mount (damper). As such, in the paper the authors highlight the model of a squeeze mode hydraulic mount, then present the simulation results in the form of dynamic stiffness and damping vs. frequency plots, respectively.
Evaluation of the Operational Parameters of Ropes
Authors: Sioma Andrzej , Tytko Andrzej
Published: August 2011

This paper discusses a visual method of measuring the geometric parameters of ropes and evaluating their wear based on measurements of a three-dimensional rope model. The 3D model is created using the method of laser triangulation. Selection of appropriate geometry of camera and laser lighting arrangement allows collection of the height profile of the observed rope surface in the selected cross-section and, subsequently, building of a 3D model. The resulting model is a representation of the actual dimensions of the rope and allows determination of the parameters describing its basic geometric dimensions and condition of rope surface. Determination of those values and parameters allows estimation of the degree of rope wear. The article discusses issues related to resolution of the vision system, resolution of laser beam analysis, and resolution relating to the measurement of the height profile on the surface of the rope. Based on the model constructed in such a way, measurements are presented in order to assess the dimensional parameters and surface defects in sample rope structures. Based on tests and analyses of the three-dimensional model, a range of inspection tasks using 3D vision systems is indicated.
Energy Dissipation in Three-Layered Plate with Magnetorheological Fluid
Authors: Snamina Jacek
Published: August 2011

In the paper a sandwich plate, of rectangular form, with magnetorheological (MR) fluid core is investigated. The plate consists of two outer layers made of aluminium and an MR fluidlayer in between. The plate edges are clamped. It was assumed that the aluminium layers are pure elastic. The energy is dissipated only in the MR fluid layer. Additional assumptions concerning displacements, deformations and stresses are introduced in the calculations. The average power dissipated per unit area of the plate for selected modes of vibrations was determined. A simple method of energy assessment was presented. The results of the calculations can be useful in a semiactive control of continuous systems.
Study of Accumulated Defects of Steel Wire Ropes
Authors: Lesňák Michal , Foukal Jaroslav , Slivečka Lukáš , Trojková Jana
Published: August 2011

The article deals with the accumulated defect impact on magnetic field distribution around a magnetized rope. A study of such effects was made on a cylinder-shaped model of steel wire rope with a diameter of 40 mm, in which individual wires with a diameter of 1 mm are parallel to the cylinder axis. Defects are wire breaks with the face distance of 1 mm. An analysis was made of the accumulated defect responses in a rope in one radial direction at various distances from the rope axis, then in two different radial directions, and surface defects in the direction of the rope.
Construction and Simulation of a 2S1 Tracked Vehicle Model and its Verification Using Vertical Forces on the Road Wheels while Overcoming a Single Obstacle
Authors: Nabagło Tomasz , Jurkiewicz Andrzej , Apostoł Marcin , Micek Piotr
Published: August 2011

We present information about construction tasks of tracked vehicle model in MSC.ADAMS computer program. Kinematic and dynamic relationships inside entire suspension system are described here. Elements of the vehicle are grouped in few subsystems, like suspension, wheels or tracks. The significant accent is put on the tracks with its force connections. Those connections are between all track links as also between wheels, links and ground surface. Also significant accent are put on damping value estimation. It is estimated based on tolerance area of characteristics of real damper element, which is applied in this type of vehicles. In next part of the article, process of appropriate damping characteristics selection is described. This process is applied for high fidelity model building.
Micromechanical and Tribological Properties of Nanocomposite nc-TiC/a-C Coatings
Authors: Kot Marcin , Moskalewicz Tomasz , Wendler Bogdan , Czyrska-Filemonowicz Aleksandra , Rakowski Wiesław
Published: August 2011

The nanocomposite coatings composed of nanocrystalline TiC grains embedded in hydrogen free amorphous carbon a-C matrix (nc-TiC/a-C) were deposited by magnetron sputtering on the two substrates, oxygen hardened Ti-6Al-4V alloy and heat treated VANADIS 23 steel. The Ti-6Al-4V alloy was oxygen hardened by plasma glow discharge. Micro-mechanical and tribological properties as well as coating adhesion to the substrates were investigated. Micro/nanostructure of the coatings and the substrates were examined using scanning- and transmission electron microscopy methods as well as X-ray diffractometry. Nano-, microhardness tests performed for the coated materials showed average hardness 13.4-14.7 GPa and modulus of elasticity 160 GPa. Scratch test revealed good adhesion of coatings to the both substrates. The nanocomposite coatings significantly improved tribological properties of the titanium alloy and steel, increased wear resistance and decreased friction coefficient.
Advanced Controlling of the Prototype of SMA Linear Actuator
Authors: Dominik Ireneusz
Published: August 2011

During research on SMA wires the prototype of linear position actuator was built. The shape memory alloy (SMA) wires used in construction of the actuator are nonlinear and time variant. Thus, it was decided to use a fuzzy controller to control the actuator. However, because of the nature of SMA wires which work by changes of their temperature, after a few minutes of continuous work the actuator did not work accurately. In other words, the existing singleton values in a knowledge base were inappropriate. That is why each time after longer continuous work of the actuator it was needed to manually find and change the mentioned values. It took a lot of time and effort so eventually it was decided to create a real time auto-tuning algorithm which could identify crucial parameters of the actuator each time when it was needed. Together with initial values learning algorithm the advanced controlling of SMA actuator was created.
Surface of Alumina Films after Prolonged Breakdowns in Galvanostatic Anodization
Authors: Girginov Christian , Kozhukharov Stephan
Published: August 2011

Breakdown phenomena are investigated at continuous isothermal (20∘C) and galvanostatic (0.2–5 mA cm−2) anodizing of aluminum in ammonium salicylate in dimethylformamide (1 M AS/DMF) electrolyte. From the kinetic -curves, the breakdown voltage () values are estimated, as well as the frequency and amplitude of oscillations of formation voltage () at different current densities. The surface of the aluminum specimens was studied using atomic force microscopy (AFM). Data on topography and surface roughness parameters of the electrode after electric breakdowns are obtained as a function of anodization time. The electrode surface of anodic films, formed with different current densities until the same charge density has passed (2.5 C cm−2), was assessed. Results are discussed on the basis of perceptions of avalanche mechanism of the breakdown phenomena, due to the injection of electrons and their multiplication in the volume of the film.
Synthetic Pre-miRNA-Based shRNA as Potent RNAi Triggers
Authors: Terasawa Kazuya , Shimizu Kazuharu , Tsujimoto Gozoh
Published: August 2011

RNA interference (RNAi) is a powerful tool for studying gene function owing to the ease with which it can selectively silence genes of interest, and it has also attracted attention because of its potential for therapeutic applications. Chemically synthesized small interfering RNAs (siRNAs) and DNA vector-based short hairpin RNAs (shRNAs) are now widely used as RNAi triggers. In contrast to expressed shRNAs, the use of synthetic shRNAs is limited. Here we designed shRNAs modeled on a precursor microRNA (pre-miRNA) and evaluated their biological activity. We demonstrated that chemically synthetic pre-miRNA-based shRNAs have more potent RNAi activity than their corresponding siRNAs and found that their antisense strands are more efficiently incorporated into the RNA-induced silencing complex. Although greater off-target effects and interferon responses were induced by shRNAs than by their corresponding siRNAs, these effects could be overcome by simply using a lower concentration or by optimizing and chemically modifying shRNAs similar to synthetic siRNAs. These are challenges for the future.
Examining the Racial Crossover in Mortality between African American and White Older Adults: A Multilevel Survival Analysis of Race, Individual Socioeconomic Status, and Neighborhood Socioeconomic Context
Authors: Yao Li , Robert Stephanie A.
Published: August 2011

We examine whether individual and neighborhood socioeconomic context contributes to black/white disparities in mortality among USA older adults. Using national longitudinal data from the Americans' Changing Lives study, along with census tract information for each respondent, we conduct multilevel survival analyses. Results show that black older adults are disadvantaged in mortality in younger old age, but older black adults have lower mortality risk than whites after about age 80. Both individual SES and neighborhood socioeconomic disadvantage contribute to the mortality risk of older adults but do not completely explain race differences in mortality. The racial mortality crossover persists even after controlling for multilevel SES, suggesting that black older adults experience selective survival at very old ages. Addressing the individual and neighborhood socioeconomic disadvantage of blacks is necessary to reduce mortality disparities that culminate in older adulthood.
Atypical Strokes in a Young African American Male: A Case of Mitochondrial Encephalopathy Lactic Acidosis and Stroke-Like Episodes (MELAS) Syndrome
Authors: Sanchez Jully M. , Tan Judy Ann , Farmakiotis Dimitrios , Aggarwal Vikas
Published: August 2011

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a rare but important cause of stroke-like symptoms which can often be missed Thambisetty and Newman 2004. We describe a case of a young male presenting with stroke-like episodes, later diagnosed with MELAS in an attempt to improve the understanding about diagnosing MELAS in the appropriate clinical context.
Transient Non-Autoimmune Hyperthyroidism of Early Pregnancy
Authors: Goldman Alexander M. , Mestman Jorge H.
Published: August 2011

It is characterized by chemical and sometimes clinical hyperthyroidism, without evidence of thyroid autoimmunity that resolves spontaneously by 16 weeks gestation without significant obstetrical complications.
Plasticity of Cells andEx VivoProduction of Red Blood Cells
Authors: Hiroyama Takashi , Miharada Kenichi , Kurita Ryo , Nakamura Yukio
Published: August 2011

The supply of transfusable red blood cells (RBCs) is not sufficient in many countries. If transfusable RBCs could be produced abundantly from certain resources, it would be very useful. Our group has developed a method to produce enucleated RBCs efficiently from hematopoietic stem/progenitor cells present in umbilical cord blood. More recently, it was reported that enucleated RBCs could be abundantly produced from human embryonic stem (ES) cells. The common obstacle for application of these methods is that they require very high cost to produce sufficient number of RBCs that are applicable in the clinic. If erythroid cell lines (immortalized cell lines) able to produce transfusable RBCsex vivowere established, they would be valuable resources. Our group developed a robust method to obtain immortalized erythroid cell lines able to produce mature RBCs. To the best of our knowledge, this was the first paper to show the feasibility of establishing immortalized erythroid progenitor cell lines able to produce enucleated RBCsex vivo. This result strongly suggests that immortalized human erythroid progenitor cell lines able to produce mature RBCsex vivocan also be established.
Epigenetic Regulation of Mesenchymal Stem Cells: A Focus on Osteogenic and Adipogenic Differentiation
Authors: Teven Chad M. , Liu Xing , Hu Ning , Tang Ni , Kim Stephanie H. , Huang Enyi , Yang Ke , Li Mi , Gao Jian-Li , Liu Hong , Natale Ryan B. , Luther Gaurav , Luo Qing , Wang Linyuan , Rames Richard , Bi Yang , Luo Jinyong , Luu Hue H. , Haydon Rex C. , Reid Russell R. , He Tong-Chuan
Published: August 2011

Stem cells are characterized by their capability to self-renew and terminally differentiate into multiple cell types. Somatic or adult stem cells have a finite self-renewal capacity and are lineage-restricted. The use of adult stem cells for therapeutic purposes has been a topic of recent interest given the ethical considerations associated with embryonic stem (ES) cells. Mesenchymal stem cells (MSCs) are adult stem cells that can differentiate into osteogenic, adipogenic, chondrogenic, or myogenic lineages. Owing to their ease of isolation and unique characteristics, MSCs have been widely regarded as potential candidates for tissue engineering and repair. While various signaling molecules important to MSC differentiation have been identified, our complete understanding of this process is lacking. Recent investigations focused on the role of epigenetic regulation in lineage-specific differentiation of MSCs have shown that unique patterns of DNA methylation and histone modifications play an important role in the induction of MSC differentiation toward specific lineages. Nevertheless, MSC epigenetic profiles reflect a more restricted differentiation potential as compared to ES cells. Here we review the effect of epigenetic modifications on MSC multipotency and differentiation, with a focus on osteogenic and adipogenic differentiation. We also highlight clinical applications of MSC epigenetics and nuclear reprogramming.
Epidemiology and Etiology of Young Stroke
Authors: Griffiths Dayna , Sturm Jonathan
Published: August 2011

Introduction. Stroke in people under 45 years of age is less frequent than in older populations but has a major impact on the individual and society. In this article we provide an overview of the epidemiology and etiology of young stroke.Methods. This paper is based on a review of population-based studies on stroke incidence that have included subgroup analyses for patients under 45 years of age, as well as smaller community-based studies and case-series specifically examining the incidence of stroke in the young. Trends are discussed along with the relative frequencies of various etiologies.Discussion. Stroke in the young requires a different approach to investigation and management than stroke in the elderly given differences in the relative frequencies of possible underlying causes. It remains the case, however, that atherosclerosis contributes to a large proportion of stroke in young patients, thus, conventional risk factors must be targeted aggressively.
A Role for Estrogen Receptor Phosphorylation in the Resistance to Tamoxifen
Authors: de Leeuw Renée , Neefjes Jacques , Michalides Rob
Published: August 2011

About two thirds of all human breast cancer cases are estrogen receptor positive. The drug of first choice for these patients is tamoxifen. However, about half of the recurrences after removal of the primary tumor are or become resistant to this drug. While many mechanisms have been identified for tamoxifen resistance in the lab, at present only a few have been translated to the clinic. This paper highlights the role in tamoxifen resistance of phosphorylation by different kinases on different sites of the estrogen receptor. We will discuss the molecular pathways and kinases that are involved in phosphorylation of ERα and how these affect tamoxifen resistance. Finally, we will elaborate on the clinical translation of these observations and the possibility to predict tamoxifen responses in patient tumor samples before treatment onset. The findings made originally on the bench may translate into a better and personalized treatment of breast cancer patients using an old and safe anticancer drug: tamoxifen.
Bioinformatic Analysis ofLeishmania donovaniLong-Chain Fatty Acid-CoA Ligase as a Novel Drug Target
Authors: Kaur Jaspreet , Tiwari Rameshwar , Kumar Arun , Singh Neeloo
Published: August 2011

Fatty acyl-CoA synthetase (fatty acid: CoA ligase, AMP-forming; (EC 6.2.1.3)) catalyzes the formation of fatty acyl-CoA by a two-step process that proceeds through the hydrolysis of pyrophosphate. Fatty acyl-CoA represents bioactive compounds that are involved in protein transport, enzyme activation, protein acylation, cell signaling, and transcriptional control in addition to serving as substrates for beta oxidation and phospholipid biosynthesis. Fatty acyl-CoA synthetase occupies a pivotal role in cellular homeostasis, particularly in lipid metabolism. Our interest in fatty acyl-CoA synthetase stems from the identification of this enzyme, long-chain fatty acyl-CoA ligase (LCFA) by microarray analysis. We found this enzyme to be differentially expressed byLeishmania donovaniamastigotes resistant to antimonial treatment. In the present study, we confirm the presence of long-chain fatty acyl-CoA ligase gene in the genome of clinical isolates ofLeishmania donovanicollected from the disease endemic area in India. We predict a molecular model for this enzyme forin silicodocking studies using chemical library available in our institute. On the basis of the data presented in this work, we propose that long-chain fatty acyl-CoA ligase enzyme serves as an important protein and a potential target candidate for development of selective inhibitors against leishmaniasis.
Stenting of Anomalous Left Main Coronary Artery Stenosis in an Adult with a Retroaortic Course
Authors: Charan Lanjewar , Shiradkar Santosh , Kerkar P. G. , Ashish Agrawal
Published: August 2011

Coronary bypass graft has been the conventional treatment of choice in anomalous left man coronary artery stenosis. We are reporting an interesting case with anomalous left main coronary artery originating from right aortic sinus having retroaortic course complicated by significant atherosclerotic narrowing of the vessel and its percutaneous management.
Acid Phosphatases of Budding Yeast as a Model of Choice for Transcription Regulation Research
Authors: Sambuk Elena V. , Fizikova Anastasia Yu. , Savinov Vladimir A. , Padkina Marina V.
Published: August 2011

Acid phosphatases of budding yeast have been studied for more than forty years. This paper covers biochemical characteristics of acid phosphatases and different aspects in expression regulation of eukaryotic genes, which were researched using acid phosphatases model. A special focus is devoted to cyclin-dependent kinase Pho85p, a negative transcriptional regulator, and its role in maintaining mitochondrial genome stability and to pleiotropic effects ofpho85mutations.
Amelioratory Effect of Nanoconjugated Vancomycin on Spleen during VRSA-Induced Oxidative Stress
Authors: Chakraborty Subhankari Prasad , KarMahapatra Santanu , Sahu Sumanta Kumar , Pramanik Panchanan , Roy Somenath
Published: August 2011

Objective. The aim of the present study was to evaluate the possible antioxidant effects of nanoconjugated vancomycin against VRSA infection on select makers of oxidative damage and antioxidant status in spleen.Methods. A coagulase-positive VRSA strain was used for this study. VRSA infection was developed in Swiss mice by intraperitoneal injection of 5 × 106 CFU/mL bacterial solutions. VRSA-infected mice were treated with nanoconjugated vancomycin at its effective dose for 10 days. After decapitation, blood was used for determination of viable bacteria count and spleen was excised from control and experimental groups, homogenized and used for different biochemical estimations.Results. Nitrate level, myeloperoxidase activity, lipid peroxidation, protein oxidation, oxidized glutathione, and DNA fragmentation level were increased significantly (P<0.05) in spleen of VRSA-infected group as compared to control group, and reduced glutathione level, activity of SOD, CAT, GPx, GR, and GST were decreased significantly (P<0.05); which were increased or decreased significantly (P<0.05) near to normal in nanoconjugated vancomycin-treated group.Conclusion. These findings suggest the potential use and beneficial role of nanoconjugated vancomycin against VRSA-infection-induced oxidative stress and DNA damage in spleen.
Prevalence and Impact of Thyroid Disorders on Maternal Outcome in Asian-Indian Pregnant Women
Authors: Nambiar Vimal , Jagtap Varsha S. , Sarathi Vijaya , Lila Anurag R. , Kamalanathan Sadishkumar , Bandgar Tushar R. , Menon Padmavathy S. , Shah Nalini S.
Published: August 2011

Aims. To establish the prevalence and the effect of thyroid dysfunction on pregnancy outcomes in Asian-Indian population.Subjects and Methods. The study cohort comprised of 483 consecutive pregnant women in the first trimester attending the antenatal clinic of a tertiary center in Mumbai, India. Thyroid hormone levels and thyroid peroxidase antibody were estimated. Patients with thyroid dysfunction were assessed periodically or treated depending on the severity. Subjects were followed until delivery.Results. The prevalence of hypothyroidism, Graves' disease, gestational transient thyrotoxicosis, and thyroid autoimmunity (TAI) was 4.8% (), 0.6% (), 6.4 % (), and 12.4% (), respectively. Forty percent of the hypothyroid patients did not have any high-risk characteristics. Hypothyroidism and TAI were associated with miscarriage ( and , resp.).Conclusions. The prevalence of hypothyroidism (4.8%) and TAI (12.4%) is high. TAI and hypothyroidism were significantly associated with miscarriage.
Thyroid Disorders and Diabetes Mellitus
Authors: Hage Mirella , Zantout Mira S. , Azar Sami T.
Published: August 2011

Studies have found that diabetes and thyroid disorders tend to coexist in patients. Both conditions involve a dysfunction of the endocrine system. Thyroid disorders can have a major impact on glucose control, and untreated thyroid disorders affect the management of diabetes in patients. Consequently, a systematic approach to thyroid testing in patients with diabetes is recommended.
Development of a Method for a Sensitive Simultaneous Determination of Dopamine and Paracetamol in Biological Samples and Pharmaceutical Preparations
Authors: Babaei Ali , Dehdashti Aliyeh , Afrasiabi Mohammad
Published: August 2011

A chemically modified electrode is constructed based on multiwalled carbon nanotube—modified glassy carbon electrode (MWCNTs/GCE). The measurements were carried out by application of differential pulse voltammetry (DPV), cyclic voltammetry (CV), and chronoamperometry (CA) methods. Application of DPV method showed wide linear range of DA from 1 μM to 540 μM and a detection limit of 0.098 μM (S/N=3). The linear range of PAR of 3 μM to 300 μM and a detection limit of 0.15 μM, were obtained. The modified electrode showed electrochemical responses with high sensitivity, high selectivity, and excellent stability for DA and PAR determination at optimal conditions, which makes it a suitable sensor for simultaneous submicromolar detection of DA and PAR in solutions. The analytical performance of this sensor has been evaluated for detection of DA and PAR in human serum, human urine, and pharmaceutical preparation with satisfactory results.
Databases and Bioinformatics Tools for the Study of DNA Repair
Authors: Milanowska Kaja , Rother Kristian , Bujnicki Janusz M.
Published: August 2011

DNA is continuously exposed to many different damaging agents such as environmental chemicals, UV light, ionizing radiation, and reactive cellular metabolites. DNA lesions can result in different phenotypical consequences ranging from a number of diseases, including cancer, to cellular malfunction, cell death, or aging. To counteract the deleterious effects of DNA damage, cells have developed various repair systems, including biochemical pathways responsible for the removal of single-strand lesions such as base excision repair (BER) and nucleotide excision repair (NER) or specialized polymerases temporarily taking over lesion-arrested DNA polymerases during the S phase in translesion synthesis (TLS). There are also other mechanisms of DNA repair such as homologous recombination repair (HRR), nonhomologous end-joining repair (NHEJ), or DNA damage response system (DDR). This paper reviews bioinformatics resources specialized in disseminating information about DNA repair pathways, proteins involved in repair mechanisms, damaging agents, and DNA lesions.
A Case of Thrombotic Thrombocytopenia Purpura Associated with Systemic Lupus Erythematosus: Diagnostic Utility of ADAMTS-13 Activity
Authors: Yamada Risa , Nozawa Kazuhisa , Yoshimine Takashi , Takasaki Yoshinari , Ogawa Hideoki , Takamori Kenji , Sekigawa Iwao
Published: August 2011

Thrombotic thrombocytopenia purpura (TTP) caused by a deficiency in ADAMTS-13 activity is considered to involve a subset of thrombotic microangiopathy (TMA). Although concept of TTP is included under the umbrella of TMA, discrimination of TTP from TMA is occasionally difficult in an autoimmune disorder. Herein, we report a case with TTP associated with systemic lupus erythematosus (SLE). In this case, it was difficult to discriminate TTP from TMA and the measurement of ADAMTS-13 activity was useful for obtaining an accurate diagnosis. SLE patients having thrombocytopenia in complication with anemia should be considered a monitoring of ADAMTS-13 activity even though the patients lacked symptoms of TTP related to the microvascular coagulation.
Can Levothyroxine Be Taken as Evening Dose? Comparative Evaluation of Morning versus Evening Dose of Levothyroxine in Treatment of Hypothyroidism
Authors: Rajput Rajesh , Chatterjee Sumanto , Rajput Meena
Published: August 2011

152 drug naïve primary hypothyroid patients were divided into morning (Group 1) and evening (Group 2) dosing group and evaluated for change in biochemical profile, physical functioning and Quality of Life during the course of 12 weeks of study. At the end of 12 weeks 70 (90.90%) subjects in Group 1 and 72 (96%) in Group 2 achieved euthyroidism. On evaluation clinical symptoms and total clinical scores improved in both the groups at the end of 6 and 12 weeks. Significant improvement in thyroid profile was seen in both the groups at the end of 6 and 12 weeks (Pvalue <.0001). On intergroup comparison, no significant difference in thyroid profile was seen at 6 and 12 weeks between the morning and the evening dose group. Similar dose of levothyroxine was required to achieve euthyroidism in both the groups. Though an early restoration of euthyroidism was seen in evening group, the difference when compared to the morning group was not statistically significant. On assessment of QoL, statistically significant improvement in various parameters was seen in both the groups. Hence, from the study we inferred that evening dose is as efficacious as morning dose and provides an alternate dosing regimen.
Cytotoxicity and Induction of Inflammation by Pepsin in Acid in Bronchial Epithelial Cells
Authors: Bathoorn Erik , Daly Paul , Gaiser Birgit , Sternad Karl , Poland Craig , MacNee William , Drost Ellen M.
Published: August 2011

Introduction. Gastroesophageal reflux has been associated with chronic inflammatory diseases and may be a cause of airway remodelling. Aspiration of gastric fluids may cause damage to airway epithelial cells, not only because acidity is toxic to bronchial epithelial cells, but also since it contains digestive enzymes, such as pepsin.Aim. To study whether pepsin enhances cytotoxicity and inflammation in airway epithelial cells, and whether this is pH-dependent.Methods. Human bronchial epithelial cells were exposed to increasing pepsin concentrations in varying acidic milieus, and cell proliferation and cytokine release were assessed.Results. Cell survival was decreased by pepsin exposure depending on its concentration (F=17.4) and pH level of the medium (F=6.5) (bothP<0.01). Pepsin-induced interleukin-8 release was greater at lower pH (F=5.1;P<0.01). Interleukin-6 induction by pepsin was greater at pH 1.5 compared to pH 2.5 (mean difference 434%;P=0.03).Conclusion. Pepsin is cytotoxic to bronchial epithelial cells and induces inflammation in addition to acid alone, dependent on the level of acidity. Future studies should assess whether chronic aspiration causes airway remodelling in chronic inflammatory lung diseases.
Inflammatory Regulation of Valvular Remodeling: The Good(?), the Bad, and the Ugly
Authors: Mahler Gretchen J. , Butcher Jonathan T.
Published: August 2011

Heart valve disease is unique in that it affects both the very young and very old, and does not discriminate by financial affluence, social stratus, or global location. Research over the past decade has transformed our understanding of heart valve cell biology, yet still more remains unclear regarding how these cells respond and adapt to their local microenvironment. Recent studies have identified inflammatory signaling at nearly every point in the life cycle of heart valves, yet its role at each stage is unclear. While the vast majority of evidence points to inflammation as mediating pathological valve remodeling and eventual destruction, some studies suggest inflammation may provide key signals guiding transient adaptive remodeling. Though the mechanisms are far from clear, inflammatory signaling may be a previously unrecognized ally in the quest for controlled rapid tissue remodeling, a key requirement for regenerative medicine approaches for heart valve disease. This paper summarizes the current state of knowledge regarding inflammatory mediation of heart valve remodeling and suggests key questions moving forward.