bluuebunny/crossref_metadata_2025 huggingface dataset:
Process Behavior and Application of Dynamic Self-Adjusting Water-Transferring Composite Coat
Authors: Zhang Zeng Zhi , Du Hong Mei
Published: June 2011

A kind of dynamic water-release composite coated fiber used for water saving afforestation in desertification area is prepared. The coat is composed of polyacrylamide and montmorillonite grains with an appropriate proportion. TG/DTA thermal analyzer is used to study coat water adsorption-desorption performance. Rapid moisture tester is used to analyze the water-releasing characteristic of the coat in different temperature and different soil moisture. Environmental scanning electron microscope (ESEM) is used to observe coat surface morphology. Finally, the water-transferring mechanism is studied. The results show that polyacrylamide and montmorillonite grains have a great influence on the water retention property and water permeability of the coat, respectively. Water-transferring rate of the coat can be effectively improved by designing the proportion of polyacrylamide and montmorillonite grains. Water potential influences the water-transferring rate significantly. When the outside soil inclines to be droughty or the temperature is going up, water potential of soil is lower than the potential of the coat, polyacrylamide shrinks with dehydration. Montmorillonite grains bridge together and in the state of “bridge-connection”. Water is transferred quickly along the channels of grains and water-transferring rate of the coat accelerates. When soil is getting wet or temperature is going down, water potential of soil is higher than the potential of the coat, polyacrylamide swells because of high water-potential. Montmorillonite grains split and in the state of “bridge-break”. Water is transferred slowly relying on the absorption-desorption of polyacrylamide and water-transferring rate decreases. So the composite coat can self-adjust soil moisture to guarantee plants survival and make full use of water resources.
Subjects on Fatigue Crack Generation in High Strength Alloys for Long-Life Design
Authors: Umezawa Osamu , Morooka Satoshi
Published: June 2011

The very localized deformation processes have been found to be decisive for subsurface fatigue crack generation at the lower stress level such as the elastic incompatibility at boundaries where only a very small fraction of plastically deformed grains was detected. The material design and its microstructure modification to achieve higher fatigue resistance in long-life range are needed for the high strength alloys, which is one of the ways developing an ecomaterial. Novel systems have employed to clarify the substance crack generation and growth mechanisms of high strength alloys. The initial crack size highly depends on the maximum cyclic stress range, which implies a threshold of stress intensity range controlling mechanism. Heterogeneous microplasticity due to planar slip and restricted system is considered to play an important role on making the subsurface crack. Then, it should be progressed in the understanding of damage stage in high-cycle fatigue fracture process.
Resistive Switching and Current Conduction for Thermally Grown NiO Thin Film
Authors: Lai Chun Hung , Chen Chia Hung , Liu Chih Yi
Published: June 2011

The unipolar resistive switching (URS) properties were investigated for NiO thin film prepared by thermal oxidation of the deposited Ni layer on Pt substrate. The turn-on voltage (Vset) shows apparent variation, at which switching from a high-resistance state (off) to a low-resistance state (on) occurs. The formation and rupture of a conducting channel are commonly proposed to explain the bistable conduction states, so called the filament model. The Vset polarity and instability are discussed in the light of the filament model and the results agree with the p-type carriers known in NiO film. Current-voltage data of the on-state conduction in full-log scale follow the ohmic behavior and the temperature dependence shows the relatively stable essence. The off-state current displays space-charge limited (SCL) relation at higher field and reveals a positive temperature dependence. The dominance of the off-state conduction for resistance swtich effect is emphasized and analyzed using the impedance spectroscopy.
Composition and Dielectric Properties of Ba2Ti9O20-BaFe12O19 Ceramics
Authors: Zhang Wen Bo , Yu Hong Tao , Liu Jing Song , Cao Lin Hong
Published: June 2011

In this paper, the composition and dielectric properties of Ba2Ti9O20-BaFe12O19system ceramics were studied. The ceramics were prepared successfully through the conventional ceramic processing. The x-ray diffraction results showed that all specimens were made of multi-phases, and the sintering temperature on the phase structure of the ceramics did not affected. The effects of sintering conditions and the components on the dielectric properties were investigated in detail. The investigations indicated that the initial Ba2Ti9O20/ BaFe12O19ratio had a great effect on the dielectric of the ceramics. The permittivity increased as the BaFe12O19content increased, whereas the dielectric loss decreased in the composite systems, which could be attributed to the variance in the formation of phases. At last, we suggested that further studies on magnetic properties should be considered for the application in electronic devices like LC filter.
Deposition and Characterization of Pyroelectric PMN-PT Thin Films for Uncooled Infrared Focal Plane Arrays
Authors: Tang Yan Xue , Tian Yue , Wang Fei Fei , Shi Wang Zhou
Published: June 2011

Modern uncooled infrared focal plane arrays (UFPA) development is oriented toward silicon microstructure monolithic arrays by employing pyroelectric thin films with continuing trends in high performance and miniaturization. In order to exploit high performance pyroelectric thin films, (1−x)Pb(Mg1/3Nb2/3)O3−xPbTiO3(PMN-PT) thin films withx= 0.26 were deposited on LaNiO3/Si substrates by the radio-frequency magnetron sputtering technique. (110) preferred orientation thin films with pure perovskite structures were obtained at a substrate temperature of 500°C. The ferroelectric, dielectric and pyroelectric properties of the films were investigated. The films show a typical polarization – electric filed hysteresis loop with a large remnant polarization of 17.2 μC/cm2. At room temperature, the high pyroelectric coefficient of 3.1 × 10-4C/m2K together with low dielectric constant of 470 and loss tangent of 0.04 render the film promising for uncooled infrared device applications. The origin of the differences in electrical properties between the films and bulk materials has also been discussed.
Dielectric Properties of Li-Doped CaCu3Ti4O12 Ceramics
Authors: He Ying , Zhang Huai Wu , Li Yuan Xun , Ling Wei Wei , Wang Yun Yan , Liu Peng
Published: June 2011

CaCu3Ti4O12 ceramics doped with 0-2.0 wt% Li2CO3 were prepared by the solid-state reaction, and their electric and dielectric properties were investigated. It is found that these ceramics had the properties of high dielectric constant and comparatively low dielectric loss. At the doping amount of 0.5 wt%, the dielectric constant is kept to be 105 with weak frequency dependence below 105 Hz, and its loss tangent (tan δ) is suppressed below 0.1 between 300 Hz-5 kHz (with the minimum value of 0.06 at 1 kHz from 218 K to 338 K). The impedance spectroscopy analysis confirms that the decrease of dielectric loss is mainly due to the increase of resistance in the grain boundary, which may be related to the influence of Ti4O7 secondary phase. Our result indicates that doping Li2CO3 is an efficient method to optimize the dielectric properties of CaCu3Ti4O12.
Effect of Hf Doping on the Dielectric Properties of Barium Zirconate Titanate Ceramics
Authors: Cai Wei , Fu Chun Lin , Gao Jia Cheng , Deng Xiao Ling , Jiang Wei Hai , Lin Ze Bin
Published: June 2011

Pure and Hf-doped BaZr0.2Ti0.8O3(short for BZT) ceramics are prepared by a conventional solid state reaction method. The crystal structure and dielectric properties of Hf-doped BZT ceramics have been investigated. The results indicate that Hf4+ ions have entered the unit cell maintaining the perovskite structure of solid solution and the pure and Hf-doped BZT ceramics are cubic phase. Addition of hafnium leads to the fall of the phase transition temperature and can decrease the dielectric loss of BZT ceramics at room temperature. When Hf content is more than 0.5 wt.%, the diffuseness of the phase transition enhances with the increasing of Hf content and when Hf content is 3 wt.%, the diffuseness of Hf-doped BZT ceramics is more than that of the pure BZT ceramics.
Hydrothermal Synthesis and Characterization of (Na0.8K0.2)0.5Bi0.5TiO3 Perovskite-Type Oxides with Cubic Morghology
Authors: Wang Yan , Long Jian Ping , Deng Miao , Li Jun Feng , Kong Qin
Published: June 2011

The (Na0.8K0.2)0.5Bi0.5TiO3 perovskite-type solid solution was prepared under mild condition at 160°C using Ti(OC4H9)4, Bi(NO3)3•5H2O as Bi and Ti sources by a mechanical hydrothermal method. It is suggested that mineralizer plays an important role in facilitating the crystallization of obtained products and promoting the formation of perovskite phase. The crystallized products were characterized by means of XRD, SEM and DSC-TG. The results show that the well-developed crystallite with a pure pervoskite structure has been formed. The powders with regular cubic morphology exhibit low agglomeration and narrow particles size distribution in the range of 3~6μm.
Fracture Behavior of Organic Silicon Rubber at Different Extension Rate
Authors: Liu Xiao , Zhang Wei Fang , Liu Sheng Wang , Hou Wei Guo , Ding Mei Li
Published: June 2011

Fracture behavior of organic silicon rubber at the extension rate of 100, 300, 500 and 700 mm/min at room temperature was studied in this paper. The fracture surface morphology was observed by scanning electron microscopy (SEM). Effects of different extension rate on the tensile strength tensile fracture behavior and mechanism were investigated. The results showed that fracture of the organic silicon rubber was composed by flat region and rough region, while the rough region was relatively small. With the increasing extension rate, the area of flat region enlarged while rough region decreased, and the secondary cracks appeared when the extension rate reached critical value. The relationship of the tensile strength and elongation with the extension rate were similar, both of which rised and then droped as the extension rate increased, and further studies were needed for the fracture mechanism.
Effects of Current Density on the Microstructure and Properties of Electrodeposited Black Cr-C Nano-Composite Coatings on Steel Substrate
Authors: Li Xue Song , Yang Yue , Yang You , Wu Hua
Published: June 2011

Eelectrodeposited black Cr-C nano-composite coating was prepared on the steel substrate and the effects of current density on the properties of the composite coating were studied in the present paper. The surface morphology and phase composition of the composite coatings were analyzed by means of scanning electronic microscopy (SEM) and X-ray diffractometer (XRD). Microhardness was determined by micrometer and the wear resistance of the coatings was evaluated by CETR using a universal materials tester (UMT). The results showed that formed under the condition of current density of 100A/dm2, temperature of 15°C, and the optimum particle content in electrolyte was 10g/l. The maximum microhardness of black Cr-C nano-composite coating was 10.8 Gpa, simutaneously, the wearing resistance of the coating improved significantly compared to the steel substrate.
Efficient Guiding of Terahertz Wave by Thin Metal Corrugation on Both Surfaces
Authors: Tian Dong Bin , Zhang Huai Wu , Wen Qi Ye , Ling Wei Wei , Song Yuan Qiang , Zhong Zhi Yong
Published: June 2011

Thin structured periodic metallic corrugations on both sides of low-loss thin polythene slab are proposed to efficiently guide terahertz (THz) wave based on the surface plasmon polaritons (SPPs). THz time domain spectrometer was used to measure the transmission characteristic. Long-lasting Fabry-Perot resonance modes are demonstrated due to the interferences of the multiple reflected waves.
Fabrication and Thermoelectricity of (Ca1-XAX)3Co4O9 Composition-Spread Films
Authors: Wang Qun Jiao
Published: June 2011

Combinatorial pulsed laser deposition (CPLD) is proving to be an efficient, low-cost tool in synthesis and characterization of thermoelectric composition-spread films. With the help of CPLD, (Ca1-xAx)3Co4O9 composition-spread films were fabricated successfully on TiO2 (100) substrate , and their thermoelectric (TE) properties and structure were evaluated by the multi-channel thermoelectric measurement system and concurrent X-ray analysis respectively. The largest power factor in (Ca1-xSrx)3Co4O9 film library was achieved as 1.67µW/cmK2. The influence of substitution on TE properties was investigated by doping different ions into Ca3Co4O9. By comparing Seebeck coefficients and conductivities of the films, it can be drawn that the substitution ions with smaller size are potential candidates for good TE properties. The dependence of TE properties of (Ca1-xSrx)3Co4O9 films on temperature shows that good TE properties can be achieved when temperature is above 150K.
Functionalization of Multiwalled Carbon Nanotubes by Poly (Ethlylene Glycol) and Non-Isothermal Crystallization Kinetic Study
Authors: Gao Song , Sui Kun Yan , Wu Zhi Ming , Wu Wen Wen , Xia Yan Zhi
Published: June 2011

Multi-walled carbon nanotubes (MWNT) were successfully chemically modified (MWNT-COOH) and reacted with polyethylene glycol (PEG) to prepare nanocomposites. As- prepared kinds of functionalized MWNT (MWNT-g-PEG) were characterized with FTIR, TGA and TEM. Nonisothermal crystallization kinetics of MWNT-g-PEG composites was investigated by differential scanning calorimeter (DSC). The kinetics was analyzed using the Ozawa and Avrami equation modified by Jeziorny. The results showed that the Ozawa approach failed to describe the crystallization behavior of nanocomposites, whereas the modified Avrami analysis could explain the behavior of MWNT-g-PEG nanocomposite only. It is observed that the presence of MWNT hindered the mobility of PEG chains and decreased the overall crystallization rate. It was found that the crystallization behavior of MWNT-g-PEG nanocomposite was strongly affected by the incorporation of MWNT. The data for the nonisothermal crystallization could be analyzed properly by the Avrami equation modified by Jeziorny. The results showed that the presence of MWNT decreased the overall nonisothermal crystallization rate of the PEG chains which were grafted onto the MWNT due to MWNT might act as physical hindrances retarding the mobility of PEG chains and decreased the crystallinity.
Magnetic-Field-Assisted Hydrothermal Growth of Manganese Dioxide Nanostructures and their Phase Transformation
Authors: Hu Ye Min , Zhu Ming Yuan , Li Ying , Jin Hong Ming , Zhu Zhen Zhen
Published: June 2011

MnO2 nanostructures were successfully synthesized by a magnetic-field-assisted hydrothermal approach. By applying a pulsed magnetic field to the reaction system, the crystal phase transformation progress of MnO2 at different temperature has been changed comparing to those synthesized without magnetic field. The effect of pulsed magnetic field on the growth of MnO2 was investigated by tracking the phase of the sample by using X-ray diffraction. It is found the pulsed magnetic field has an obvious effect on the nucleation and growth of MnO2 nanostructures and therefore influences the phase transformation.
Polar and Nonpolar ZnO Nanowire QWs Grown with PLD Using Nanowire Arrays with Tuning Density as Physical Templates
Authors: Cao Bing Qiang , Wei Hao Ming , Hu Xi Lun , Gong Hai Bo
Published: June 2011

The encountered difficulties that prevent ZnO nanowires from being used as light-emitters are p-type doping and quantum well (QW) integration. The growth of homogenous nanowire quantum wells is usually influenced by the shadowing effect associated with nanowire growth density. In this paper, based on the growth density control of nanowire array, a new two-step pulsed laser deposition (PLD) strategy was demonstrated to grow two kinds of ZnO nanowire QWs, e.g. radial nonpolar QW and axial polar QW. The growth-density control of ZnO nanowires was realised by introducing a wetting layer and adjusting the substrate-target distances. The structural and optical characterizations of these two kinds of nanowire QWs prove that the radial nanowire QWs are more homogenous than axial QWs, which also show better optical properties.
Synthesis and Electrochemical Performances of Electroactive Nano Layered Organic-Inorganic Perovskite Containing Trivalent Iron Ion
Authors: Wu Jing , Zhou Xun , Liu Han Xing , Lin Zhi Dong , Chen Gao Feng
Published: June 2011

A steady layered organic-inorganic perovskite hybrid containing Fe3+ was prepared in the air with phenosafranine as organic sheets, the Fe(CN)63- as inorganic sheets. We utilized the Fe(CN)63- as inorganic sheets of perovskite hybrids, which may help to stabilize the unusual metal-deficient layered structures. The results of X-ray diffractometry (XRD) and scanning electron microscopy (SEM) show that the hybrid is typical layered perovskite structure. The hybrid was mixed with paraffin to form a hybrid paste for the hybrid paste electrode. Electrochemical characteristics of carbon paste electrode (CPE) modified by hybrid were investigated with cyclic voltammetry. The modified electrode can accelerate the electron-transfer to improve the electrochemical reaction reversibility and be use for the determination of chemicals. The interactions between sodium nitrite (NaNO2), sodium bromide (NaBr), hydroxylammonium chloride (NH2OH·HCl), hydroquinone (C6H6O2) with hybrid were studied. The modified electrode exhibits good electrochemical activity. The hybrid can be used as electrochemical materials.
Microstructure and Magnetic Properties of the CoPtRu-SiO2 Single and CoPtRu-SiO2/Co72Pt28-SiO2 Double Layer Nanocomposite Films
Authors: Tang Ru Jun , Zhang Wan Li , Li Yan Rong
Published: June 2011

In this work, the CoPtRu nanocomposite films with were fabricated on the Ru seed layer. The effects of Ru content on the microstructure and magnetic properties of the CoPtRu-SiO2single layer nanocomposite films, and magnetic properties of the CoPtRu-SiO2/Co72Pt28-SiO2double layer nanocomposite films were studied. Results showed that with an increase of Ru content in the CoPtRu film, the ordering degree ofhcp-CoPtRu decreased, the volume of soft magneticfccphase increased, both the anisotropy constant and the saturation magnetization of the CoPtRu film decreased greatly. As a result, the anisotropy field of the film did not decrease notably. Therefore, the coercivity of the CoPtRu-SiO2/Co72Pt28-SiO2double layer film was very close to that of Co72Pt28-SiO2single layer film at both room temperature and low temperature.
Synthesis of Fe3O4 Nanocrystals and Application in Photocatalytic Degradation of Levofloxacin Lactate
Authors: Hu Xiao Dan , Zhang Hai Qian , Cao Dong Mei
Published: June 2011

Fe3O4nanocrystals were synthesized with polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) as dispersant respectively by solvothermal process. The nanocrystals were characterized in order to elucidate the morphology and structure by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) respectively. The results indicated that Fe3O4 nanocrystals were cubic phases, and the morphologies of samples were globular nanoparticles structure no matter what dispersant was. The photocatalytic degradation of levofloxacin lactate (LVFX) revealed that Fe3O4nanocrystals promoted the degradation of LVFX. As the UV radiation time was only 30 min, the photocatalytic degradation percentage of LVFX with Fe3O4(magnetite) as catalyst was about 92%. However, the direct photolysis degradation percentage of LVFX without Fe3O4is about 85%.
Fabrication and Characterization of Fullerene / Dibenzo-Tetrathiafulvalene Solar Cells
Authors: Suzuki Atsushi , Yano Katsuya , Oku Takeo
Published: June 2011

Fabrication and characterization of fullerene (C60) / dibenzotetrathiafulvalene (DBTTF) solar cells were carried out. Photovoltaic and optical properties of the organic solar cells were investigated. Transmission electron microscopy, x-ray and electron diffraction confirmed that the bulk heterojunction thin films had microstructure of C60 crystal phase in DBTTF amorphous phase. The photovoltaic performance of the bulk heterojunction solar cell would be originated in the extent of electron diffusion across interface around the microstructure. Photovoltaic mechanism was discussed on the basis of experimental results.
High Efficiency Algorithm for the Dipolar Interaction Energy of 2D Magnetic Nanoparticle Systems
Authors: Tang Ke , Yang Hong Jie , Cao Lin Hong , Yu Hong Tao , Liu Jing Song , Wang Jun Xia
Published: June 2011

Most of simulations often require the calculation of all pairwise interaction in large ensembles of particles, such as N-body problem of gravitation, electrostatic interaction and magnetic dipolar interaction, etc. The main difficulty in the calculation of long-range interaction is how to accelerate the slow convergence of the occurring sums. In this work, we are interested in the dipolar interaction in the two dimensional (2D) magnetic dipolar nanoparticle systems, which have attracted much attention due to both their important technological applications such as high-density patterned recording media and their rich and often unusual experimental behaviours. We develop a high efficiency algorithm based on the Lekner method to evaluate the magnetic dipolar energy for such systems, where the simulation cell is periodically replicated in the plane. Taking advantage of the symmetry of the systems, the dipolar interaction energy is expressed by rapidly converging series of modified Bessel functions in our algorithm. We found that our algorithm is better than the traditional Ewald summation method in efficiency for the regular arrays. Moreover, two simple formulas are obtained to evaluate the self-energy, which is important in the simulation of the dipolar systems.
AEC: A New Tool for EET, TFDC and Crystal Formula
Authors: Li Shi Chun
Published: June 2011

Atomic Environment Calculation (AEC) is a computation method for calculating atomic environment properties of every atom in any crystal. These properties include types of neighboring atoms and their spatial distribution, bond lengths sorted in an ascending order, atomic space coordination number, and atomic pair coordination number. AEC can output bond data for each type of atom, which is equivalent to giving a description of local cluster structure in the crystal. AEC can also be used to optimize the coordinates of the atoms in the crystal and assemble atoms into simple crystals. AEC calculates atomic environment by means of operating atoms in point groups and self-consistent calculation of coordinate. Any accidental and systematic errors in crystal structure data can be corrected by AEC.
The Cause Analysis of a Liquid CO2 Tank Explosion on a Ship
Authors: Li Wen Wei , Di Gang , Wang Rui Xin
Published: June 2011

The explosion of liquid carbon dioxide tanks are extremely rare in the world, this article describes the 125 m3 liquid carbon dioxide tank explosion that happened on a ship. This paper gives a comprehensive analysis and calculation on the explosion energy and hazard radius as well as the causes of the accident, with the explosion energy being converted to TNT equivalents. Tank explosion radiuses leading to death, serious injury and different degrees of destructions are also obtained via theoretic calculation. According to the calculation, this article points out that the direct cause of explosion is that the designer confuses the concept of " Low-temperature vessels" with the concept of " Low-temperature and Low-vessels Low Stress vessels". The reasons of the tank explosion accident are not only the mistaken design but also the operating violation. Finally the article also makes a reflection from four different perspectives.
Assessment of Stromal Invasion for Correct Histological Diagnosis of Early Hepatocellular Carcinoma
Authors: Kondo Fukuo
Published: June 2011

Stromal invasion (invasive growth of tumor tissue into portal tracts and fibrous septa) is now recognized as the most important finding in the diagnosis of the well-differentiated type of early hepatocellular carcinomas (HCCs). In differentiating stromal invasion from pseudoinvasion (benign hepatic tissue in fibrous stroma), the following 5 items are useful: (1) macroscopic or panoramic views of the histological specimen, (2) the amount of fibrous components of stroma, (3) destruction of the structure of portal tracts, (4) loss of reticulin fibers around cancer cells, and (5) cytokeratin 7 immunostaining for ductular proliferation. Knowledge of stromal invasion is also useful for a better understanding of the vasculature (hypovascular HCCs) and histological features (fatty change) of early HCCs. Invasion of preexisting arteries and portal veins causes hypo-vascularity of HCCs. Further, hypovascularity causes fatty change as a hypoxic change of cancer tissues.
Does Stroke Impair Learning in Children?
Authors: Rodrigues Sonia das Dores , Ciasca Sylvia Maria , Guimarães Inês Elcione , Elias Karla Maria Ibraim da Freiria , Oliveira Carolina Camargo , Moura-Ribeiro Maria Valeriana Leme de
Published: June 2011

Objective. To assess cognitive development and learning in children who have had strokes.Method. Twenty-nine stroke patients and 18 children with no brain lesions and no learning impairments were evaluated. For the cognitive assessment, Piaget's clinical method was used. Writing, arithmetic, and reading abilities were assessed by the school performance test.Results. The mean age at evaluation was 9.6 years. Among the 29 children, 20 had early lesions (mean of 2.4 years old). The stroke was ischemic in 18 subjects; there were 7 cases of recurrence. Six children could not answer the tests. A high index of cognitive delay and low performance in writing, arithmetic, and reading were verified. Comparison with the control group revealed that the children who have had strokes had significantly lower performances.Conclusion. In this sample, strokes impaired cognitive development and learning. It is important that children have access to educational support and cognitive rehabilitation after injury. These approaches may minimise the effects of strokes on learning in children.
Theory of Square-Wave Voltammetry of Two-Step Electrode Reaction Using an Inverse Scan Direction
Authors: Lovrić Milivoj , Komorsky-Lovrić Šebojka
Published: June 2011

A theory of square-wave voltammetry of two-step electrode reaction with kinetically controlled electron transfers is developed, and a special case of thermodynamically unstable intermediate is analyzed. If the first reaction step is reversible and the second one is quasireversible, the response splits into two peaks if the scan direction is inverted. The separation of these peaks increases with frequency.
Alternative Splicing in Self-Renewal of Embryonic Stem Cells
Authors: Cheong Clara Y. , Lufkin Thomas
Published: June 2011

Much of embryonic stem cell biology has focused on transcriptional expression and regulation of genes that could mediate its unique potential in self-renewal or pluripotency. In alignment with our present understanding on the genetic, protein, and epigenetic factors that may direct cell fate, we present a short overview of the often overlooked contribution of alternative splice variants to regulatory diversity. Progressing beyond the limitations of a fixed genomic sequence, alternative splicing offers an additional layer of complexity to produce protein variants that may differ in function and localization that can direct embryonic stem cells to specific differentiation pathways. In light of the number of variants that can be produced at key ES cell genes alone, it is challenging to consider how much more multifaceted transcriptional regulation truly is, and if this can be captured more fully in future works.
Use of Antimony in the Treatment of Leishmaniasis: Current Status and Future Directions
Authors: Haldar Arun Kumar , Sen Pradip , Roy Syamal
Published: June 2011

In the recent past the standard treatment of kala-azar involved the use of pentavalent antimonials Sb(V). Because of progressive rise in treatment failure to Sb(V) was limited its use in the treatment program in the Indian subcontinent. Until now the mechanism of action of Sb(V) is not very clear. Recent studies indicated that both parasite and hosts contribute to the antimony efflux mechanism. Interestingly, antimonials show strong immunostimulatory abilities as evident from the upregulation of transplantation antigens and enhanced T cell stimulating ability of normal antigen presenting cells when treated with Sb(V)in vitro. Recently, it has been shown that some of the peroxovanadium compounds have Sb(V)-resistance modifying ability in experimental infection with Sb(V) resistantLeishmania donovaniisolates in murine model. Thus, vanadium compounds may be used in combination with Sb(V) in the treatment of Sb(V) resistance cases of kala-azar.
The Role of Cognitive-Behavioural Therapy for Patients with Depression in Parkinson's Disease
Authors: Charidimou Andreas , Seamons John , Selai Caroline , Schrag Anette
Published: June 2011

Depression is a common complication of Parkinson's disease (PD) with considerable impact on patients' quality of life. However, at present the most appropriate treatment approach is unclear. There are limited data on antidepressant medications in PD-associated depression (dPD) and those available suggest limited efficacy and tolerability of these drugs. Cognitive behavioural therapy (CBT) has been shown to be an effective treatment of depressive disorders. Treatment of dPD with CBT may pose particular challenges, including possible different pathophysiology, physical and mental comorbidities, and barriers to treatment through disability, which do not allow simple transfer of these results to patients with dPD. However, a number of case reports, case series, and small pilot studies suggest that this is a promising treatment for patients with PD. We here summarise the published evidence on this treatment in dPD.
Pattern of epithelial cell abnormality in Pap smear: A clinicopathological and demographic correlation
Authors: Banik Urmila , Bhattacharjee Pradip , Ahamad Shahab Uddin , Rahman Zillur
Published: June 2011

Background:

In the low resource settings of a developing country, a conventional Papanicolaou (Pap) test is the mainstay screening system for cervical cancer. In order to counsel women and to organize a public health system for cervical cancer screening by Pap smear examination, it is imperative to know the pattern of premalignant and malignant lesions. This study was undertaken to find out the prevalence of an abnormal Pap smear, in a tertiary hospital of a developing country, and to carry out a clinicopathological and demographical analysis for establishing the pattern of epithelial cell abnormality in a Pap smear.

Materials and Methods:

A cross-sectional descriptive study was carried out in a total of 1699 patients who underwent Pap smear examination. The prevalence of epithelial cell abnormality in the Pap smear was calculated in proportions / percentages. Specimen adequacy and reporting was assessed according to the revised Bethesda system.

Results:

Among the total of 1699 patients who had their Pap smear done, 139 (8.18%) revealed epithelial cell abnormality. Altogether 26 smears revealed high-grade lesions and malignancy, most of which were found to be in women belonging to the 30 – 39 and ≥ 45 age group. A total of 75 (53.96%) women were in the 20 – 44 age group and 64 (46.04%) were in the ≥ 45 age group. A bimodal age distribution was detected in the epithelial cell abnormality, with the bulk being diagnosed in patients aged 45 or above. Overall one-third of the patients with an abnormal Pap smear result showed healthy cervix in per vaginal examination.

Conclusions:

A raised prevalence of epithelial cell abnormality reflects the lack of awareness about cervical cancer screening. Women aged 45 or above harbor the bulk of premalignant and malignant lesions in the Pap smear, signifying that these women are among the under users of cytological screening.
The effects of dietary hesperidin supplementation on broiler performance and chicken meat characteristics
Authors: Simitzis P. E. , Symeon G. K. , Charismiadou M. A. , Ayoutanti A. G. , Deligeorgis S. G.
Published: June 2011

Simitzis, P. E., Symeon, G. K., Charismiadou, M. A., Ayoutanti, A. G. and Deligeorgis, S. G. 2011. The effects of dietary hesperidin supplementation on broiler performance and chicken meat characteristics. Can. J. Anim. Sci. 91: 275–282. An experiment was conducted to examine the effects of supplementing broiler feed with hesperidin, a bioflavonoid that is an abundant and inexpensive by-product of citrus cultivation, on growth performance, carcass characteristics, breast meat quality characteristics and the oxidative stability of breast meat. Eighty 308-d-old Ross male broiler chickens were randomly assigned to four groups. One of the groups served as a control (C) and was given commercial basal diets, whereas the other three groups were given the same diets further supplemented with hesperidin at 1.5 g kg−1(HE1), or hesperidin at 3.0 g kg−1(HE2), or α-tocopheryl acetate at 0.2 g kg−1(VE). At 40 d of age, broilers were fasted for 12 h, weighed and slaughtered. After overnight chilling, carcasses were trimmed for breast fillets by removing skin, bones and connective tissue. The right pectoralis major muscle was used for quality parameters estimation, whereas the left pectoralis major muscle for lipid oxidation measurements. No significant differences were observed after dietary hesperidin or α-tocopheryl acetate supplementation in final body weight (kg), body weight gain (g), feed conversion rate and internal organs weight (g). Shear values (N mm−2), intramuscular fat (%) and cooking loss (%) were also not significantly influenced by the dietary treatments. Significant differences were found concerning pH24and color parameter values among the treatment groups. Measurement of lipid oxidation values showed that as hesperidin increased in the diet, malondialdehyde values decreased in tissue samples, suggesting that hesperidin particularly at 3 g kg−1exerted an antioxidant effect on chicken tissues (P<0.01). However, dietary α-tocopheryl acetate supplementation at 0.2 g kg−1of feed displayed greater antioxidant activity than hesperidin at either supplementation rate (P<0.01). In conclusion, hesperidin, an abundant component of citrus pulp, positively influences meat antioxidative properties without negative implications on growth performance and meat quality characteristics in poultry, thus appearing to be an important additive for both the consumer and the industry.
A Note on the Diophantine Equation x2 + y6 = ze, e ≥ 4
Authors: Zelator Konstantine
Published: June 2011

We consider the diophantine equation x2 + y6 = ze, e ≥ 4. We show that, when e is a multiple of 4 or 6, this equation has no solutions in positive integers with x and y relatively prime. As a corollary, we show that there exists no primitive Pythagorean triangle one of whose leglengths is a perfect cube, while the hypotenuse length is an integer square.
Mechanism of Stress Corrosion Cracking of Low Alloy Steel in Water
Authors: Chu Wu-Yang , Liu Tian-Hua , Hsiao Chi-Mei , Li Shi-Qun
Published: June 2011

For four low alloy steels with a wide range of tensile strengths, the dynamical processes of the nucleation and propagation of stress corrosion cracking (SCC) in water with various polarization conditions and in a inhibitor solution were traced with an optical microscope. The results show that if the tensile strength of the steel is higher than a critical value, which is different in the different polarization conditions, and KI>KISCC, the plastic zone in front of a loaded crack tip is enlarged with time, i.e., the delayed plastic deformation occurs in all the environments used. The nucleation and propagation of SCC will follow when this delayed plastic deformation develops to a critical condition. Neither anodic and cathodic polarization nor the inhibitor can change the feature of the delayed plasticity and the nucleation and propagation of SCC in water. In all the environments used, the KISCC is increased and da/dt is decreased with decreasing strength of the steel. Anodic polarization and the addition of the inhibitor make KISCC increase and da/dt decrease. But cathodic polarization is just opposite.
Corrosion of Carbon Steels in Mechanically Stirred Solutions 2.0M H2SO4
Authors: Przewlocka H. , Bala H.
Published: June 2011

The effects of stirring and carbon content on the corrosion of steel in deaerated 2.0M sulfuric acid have been studied. Both increases and decreases in the corrosion rate with the increasing stirring rate were observed: increased rates with higher carbon content and decreased rates with lower carbon content. Results are explained on the basis of the effect of stirring and carbon content on the cathodic evolution of hydrogen and the effect of the stirring rate on the anodic dissolution process.
Stress Corrosion Cracking of Sensitized 304 Austenitic Stainless Steel in Sulfurous Acid
Authors: Ahmad S. , Mehta M. L. , Saraf S. K. , Saraswat I. P.
Published: June 2011

Stress corrosion cracking investigations on U-bend samples of sensitized 304 austenitic stainless steel have been conducted in sulfurous acid solutions in the concentration range, 0.40 to 10% at ambient temperatures. Samples were found to fracture in solutions of more than 3% sulfurous acid. Chemical analysis of solutions after tests showed appreciable reduction in concentration of H2SO3, formation of H2SO4, and also the presence of Fe, Cr, and S ions. Some model experiments were carried out to ascertain the chemical species causing stress corrosion cracking and the role of oxygen and FeS in generating them. Bubbling of oxygen gas through (1) solution of H2SO3 with sample, (2) distilled water with FeS chips, and (3) solution of H2SO3 with FeS chips and sample, resulted in the formation of tetrathionic acid. Results indicate that the sulfurous acid does not directly cause cracking but it is the tetrathionic acid formed by either the interaction of sulfurous acid and austenitic stainless steel or the interaction of FeS and oxygen, that is responsible for cracking. Metallorgraphic examinations of the fracture confirmed intergranular cracking.
Corrosion of Carbon Steel in Hot NaOH Solutions under Heat Transfer Conditions
Authors: Yasuda M. , Okada M. , Hine F.
Published: June 2011

Corrosion of carbon steel immersed in boiling NaOH solutions under heat trasfer conditions was investigated electrochemically. The surfaces of these specimens after corrosion testing were also examined by scanning electron microscope (SEM). Carbon steel was fairly passive in NaOH solutions of 0.1, 1, and 5M in concentration under isothermal conditions, but it was corroded under heat transfer conditions. Localized corrosion, mostly pitting, took place when the caustic soda solutions became dilute. Localized high concentrations of caustic soda and nucleate boiling on the surface in the case of heat transfer, along with generation of mechanical stress in the oxide film are presumed to result in mechanical degradation of the oxide film and dissolution of both substrate and oxide.
Intergranular Stress Corrosion Cracking of Austenitic Stainless Steel at Temperatures Below 100 C — A Review
Authors: Cragnolino G. , Macdonald D. D.
Published: June 2011

The environmental and metallurgical factors in the intergranular stress corrosion cracking of austenitic stainless steel at temperatures below 100 C has been examined. The behavior of annealed and sensitized microstructures in a variety of environments, including oxygen-containing pure water and aqueous solutions containing species such as chloride, fluoride, polythionates, and other sulfur species is reviewed. Particular emphasis is placed on the role of sulfur oxyanions as aggressive species that can induce intergranular cracking at very low concentrations in industrial environments. Electrochemical and metallurgical aspects associated with the development of intergranular cracks in these environments are thoroughly discussed, and the mechanistic implications are addressed.
Effect of Water Chemistry on the Erosion-Corrosion of Aluminum in High Temperature High Velocity Water
Authors: Jones D. A.
Published: June 2011

Laboratory experiments were conducted to simulate the erosion-corrosion of aluminum fuel cladding in water-cooled, plutonium producing, nuclear reactors. Water quality was demonstrated to be critical in causing erosion-corrosion attack on aluminum in high temperature pressurized water. Very little attack occurred in distilled water, whereas attack was progressively worse in river water and well water. The extreme attack in well water was simulated by dissolving 50 ppm CaCO3 and 10 ppm SiO2 in distilled water. A distinct corrosion enhancing synergism was apparent between dissolved bicarbonate and silicate ions. In situ recordings of electrochemical potential vs time were characteristic of the extent of erosion-corrosion which was occurring on a particular specimen. Polarization resistance measurements did not have the expected sensitivity to erosion-corrosion, probably because of the complex cell geometry imposed by the erosion-corrosion testing apparatus.
Effect of Oxide Films on the Corrosion Resistance of Titanium
Authors: Schutz R. W. , Covington L. C.
Published: June 2011

A comparison of the corrosion and hydrogen uptake resistance of pickled, anodized, and thermally oxidized titanium is made. In general, thermal oxidation appears to offer better protection than the anodized or the pickled condition, thus, offering improved performance in heat exchanger applications as compared to the anodized coating that is traditionally specified for marginal service.
Effect of Temperature on the Stress Corrosion Cracking of Tempered Type 403 Martensitic Stainless Steel in Sodium Sulfate Solution
Authors: Bavarian B. , Szklarska-Smialowska Z. , Macdonald D. D.
Published: June 2011

Tempered martensitic Type 403 stainless steel has been found to suffer pitting corrosion and intergranular stress corrosion cracking in 0.01 M Na2SO4 at temperatures of 75 and 100 C, but not at the lower temperatures of 25 and 50 C. Significant sulfur (sulfate) contamination of the passive film from solution was found, but the level of contamination could not be correlated with the susceptibility of the alloy to IGSCC. Nonmetallic inclusions (MnS) and carbide precipitates were found to act as nucleation sites for corrosion pits which in turn give rise to IGSCC.
Effects of Plastic Deformation and Recrystallization Treatments on the Stress Corrosion Cracking Susceptibility of 304 Type Stainless Steels under Different Polarizing Conditions in MgCl2 Solution
Authors: Bilogan Kazimierz
Published: June 2011

Increasing amounts of prior plastic deformation are beneficial in terms of stress corrosion cracking SCC resistance under freely corroding conditions, while subsequent conventional heat treatments remove such beneficial effects. Under conditions of cathodic charging with hydrogen, the higher amounts of prior plastic deformation introduce some extra degrees of SCC susceptibility, especially after dynamic recrystallization heat treatments. X-ray studies showed that the SCC front, under freely corroding conditions in MgCl2 solution, proceeds by localized microplastic deformation along {111} and {200} austenite slip planes, stimulating the anodic dissolution process and being sustained by the hydrogen reduction reaction.
The Effect of Dissolved Oxygen and NO3− Anions on the Stress Corrosion Cracking of Type 304 Stainless Steel in Water at 290 C
Authors: Hirano H. , Aoki N. , Kurosawa T.
Published: June 2011

The effect of dissolved oxygen and NO3− anions on the intergranular stress corrosion cracking (IGSCC) and transgranular stress corrosion cracking (TGSCC) of Type 304 stainless steel has been studied in water at 290 C by using the constant extension rate tests (CERT) method. A strain rate of 3.33×10−6 sec−1 was applied. TGSCC occurred in water containing less than 100 ppb dissolved oxygen, while IGSCC occurred at concentrations greater than 1 ppm dissolved oxygen. IGSCC was accelerated by the addition of small amounts of NO3− anions, but TGSCC was suppressed by the presence of this anion. The analyses of oxide films by the Ion Microprobe Mass Analyzer (IMMA) and the construction of potential-pH diagrams for Cr-H2O, Ni-H2O, and Fe-H2O systems at 290 C were performed to consider the effect of dissolved oxygen and NO3− anions on IGSCC and TGSCC. The IMMA studies revealed that the compositions of the oxide films of Type 304 stainless steel and Fe-12Cr-9.3Ni steel (the presumed composition of grain boundaries in sensitized Type 304 stainless steel) were Cr-enriched at 200 ppb O2 level. At 1 ppm O2 level, the oxide film of Type 304 stainless steel was composed of Cr-enriched phase, but the Cr content in the oxide film of Fe-12Cr-9.3Ni steel was low. At 10 ppm O2 level, the oxide film of Type 304 stainless steel was composed of Fe and Cr, but the oxide film of Fe-12Cr-9.3Ni steel was mainly composed of Fe. The potential-pH diagram for the Cr-H2O system at 290 C indicated that the corrosion potential of Type 304 stainless steel lay in the stable potential region of Cr2O3 at low oxygen levels. On the other hand, at high oxygen levels, the corrosion potential of Type 304 stainless steel lies near the unstable potential region of Cr2O3. This unstable region corresponds to the potential at which Cr2O3 dissolves as dichromate ion (Cr2O7−−) or chromate ion (CrO4−−). The relationship between the characteristics of oxide films and the IGSCC and TGSCC of sensitized Type 304 stainless steel is discussed.
The Oxidation of Fe3O4 on Iron and Steel Surfaces
Authors: Keiser Joseph T. , Brown Chris W. , Heidersbach Robert H.
Published: June 2011

Infrared and Raman spectroscopy were used to study the oxidation of Fe3O4 on surfaces of weathering steel, carbon steel, and pure iron. Two sets of samples were polished and coated with an Fe3O4 paste. One set was moistened daily with distilled water and allowed to freely dry in air. The second set was treated in a similar manner except that every other day, a 0.1M Na2SO4 solution was used in place of the distilled water solution. In the set of samples treated only with distilled water, Fe3O4 was oxidized to γ-FeOOH on both the weathering and carbon steel surface, but oxidation of Fe3O4 was not observed on the pure iron surface. On all of the samples treated with 0.1M Na2SO4, Fe3O4 was oxidized initially to γ-FeOOH which converted to α-FeOOH after several weeks. The initial oxidation of Fe3O4 is proposed to occur by a reaction with H2O2 produced from the reduction of O2.
Corrosion of Painted Metals—A Review
Authors: Leidheiser Henry
Published: June 2011

Seven types of corrosion and precorrosion of painted metals are reviewed: blistering, early rusting, flash rusting, anodic undermining, filiform corrosion, cathodic delamination, and wet adhesion. The importance of the nature of the interfacial region between the coating and the metal is emphasized. Ten unsolved problems are described.