bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnitude of Intrinsic Electrocaloric Effect in Pb(Zr1-xTix)O3 at High Electric Fields
Authors: Feng Wen Jiang , Zhang Zhi Guo , Wu Chuang , Chen Hao
Published: May 2013

The structure transition and electrocaloric effect in PbZr1-xTixO3withx=0.5 and 0.6 were MV/m can make the structural transition be a continuous one. In addition, whenx=0.5 and 0.6 at the zero field, the first order structural transition occurs atT0=665 and 691 K, respectively. The first order structural transition comes to the second one upon the strong electric field, which leads to lower the change of specific hea. The structural transition temperature is shifted at high temperature with increasing electric field. The maximum electrocaloric effect is present at about 200 K above their corresponding Curie temperatures.
Morphology and Physical Analysis of Waste Paper Sludge Ash (WPSA) Polymeric Mortar
Authors: Ridzuan A.R.M. , Khairulniza A.A. , Fadzil M.A. , Nurliza J.
Published: May 2013

Waste paper sludge ash (WPSA) is a byproduct and problematic waste of paper industries. The investigation was driven by the increasing demand for reuse options in paper-recycling industry. This paper present on the morphology and physical analysis studies on polymerization of WPSA mortar. Two (2) types of polymeric mortar mixes containing WPSA with alkaline activators and without alkaline activators were prepared. The morphology of each mixes was determined using Spectra Electron Microscope (SEM) and the physical test is focus on compressive strength. However, the element diffraction of each mixes using Energy Dispersive X-Ray Spectroscopy (EDX) was also carried out as a method to identify the polymerization of polymeric mortar. From the result obtained it is found that the utilization of WPSA reduced the polymerization of polymeric mortar due to more pores. From the EDX analysis it is also revealed that the WPSA polymeric mortar also contained less synthetic aluminous silicate compound. However, the strength gain up to 6MPa and it is comparable with other high calcium material mortar.
High Volume Fraction Aluminum /Alumina-Fused Silica Hybrid Particulate Metal Matrix Composite
Authors: Roudini Ghodratollah , Asgharian Mehdi , Khosravi Morteza
Published: May 2013

High volume fraction Aluminum/alumina-fused silica hybrid metal matrix composites containing alumina with 0, 10, 30 and 50 wt% fused silica were produced by melt squeezing casting method. Microstructure of hybrid composite was investigated by optical microscope and scanning electron microscopy (SEM). The SEM images showed uniform distribution of fused silica particles in composite microstructure. Also compressive strength of the composites changed (310-110 MPa) with amount of fused silica.
Rheological Properties of Urea-CaLS Mixture for Urea Fertilizer Granulation
Authors: Juoi Jariah Mohamad , Nazari Farahani Irna , Mitan Nona Merry Merpati , Shaaban Azizah
Published: May 2013

The rheological properties of feedstock for granulation process are important in controlling the parameters throughout the process. This study identifies the type of fluid that mixtures of Urea and Calcium Lignosulfonates (CaLS) possessed through the viscosity profiles using a parallel plate rheometer. The viscosity behavior of mixtures with varied weight percentages (wt %) of CaLS in urea solution were analysed. Results identified that the mixtures show shear thickening behavior of non-Newtonian fluid. It is also observed that the increases of CaLS content increase the viscosity of the mixtures. Moreover, the mixture with 50 % CaLS addition is found not suitable for further investigation as its viscosity is too high (3.450-6.773 Pa.s at zero shear rate) compared to molten urea (0.002 Pa.s).
Ti6Al4V Surface Hardness Improvement by Duplex Coating
Authors: Yusuf Yusliza , Rosli Zulkifli Mohd , Juoi Jariah Mohamad , Mahamud Zainab , Loon Kwan Wai
Published: May 2013

Ti6Al4V alloy are among the most widely used materials in engineering applications. This is because their relatively beneficial properties. However, inadequate wear properties of Ti6Al4V alloy have largely constrained the application for this material. In this study, Plasma nitriding of the Ti6Al4V was performed using microwave plasma technique at 600°C for 1hour, 3 hours and 5 hours then followed with deposition of CrN on plasma nitrided samples for duplex coating purposes. Microstructural analysis and hardness measurement revealed that formation of Ti2N and TiN phases indicating the formation of compound layer is observed for substrate nitrided at temperature as low as 600°C 1 hour and a substantial increase on the surface hardness of plasma nitrided Ti6Al4V is observed with an increase of process time. The duplex coating obtained in this study has significant surface hardness property and superior as compared with CrN coatings deposited on as received Ti6Al4V.
Thermal Characterizations and Mechanical Properties of Hybrid Blends of Pva/Starch/LLDPE
Authors: Bin Ab Aziz Mohd Farhan , Rahmah Mohamed
Published: May 2013

Plastic resistance to be degraded by microbial activity has led to serious waste and landfill problems. Thus a study has been constructed to replace the non renewable and non degradable material with natural and synthetic biodegradable resources commonly available, namely Sago Starch and Polyvinyl alcohol (PVA). Hybrid blend consists of Sago Starch (SS), Polyvinyl Alcohol (PVA) and LLDPE has been developed and thermal and mechanical properties of this blend have been investigated. DSC plot for blend of various composition of PVA and SS formulated with fixed amount of LLDPE reported series of different gelation and melting temperature for SS and LLDPE. Tensile strength for all hybrid samples were found to have higher strength than pure SS blend, range from 4-6 Mpa compared to 1-2 Mpa. Modulus of Hybrid samples were range from 54.469 243.066. Increase the starch loading deceases the modulus of the blends. FTIR spectrums for all samples showed peaks at 3301 cm-1 -3322 cm-1 and 1462 cm-1 indicating that hydroxyl groups and CH2 bending vibration were presents in the blends.
Transformation of Pure Al Structure under the Influence of Electromagnetic Field
Authors: Wróbel Tomasz
Published: May 2013

In paper problem concerning inoculation of primary structure of aluminum with purity of 99,5% and 99,8%, which is realized mainly by intensification of liquid metal movement in mould is presented. In aim of realization of forced movement during the crystallization of liquid metal was used rotating electromagnetic field produced by the induction coil supplied by current with elevated frequency. The degree of structure refinement was represented by equiaxed crystals zone content on transverse section of ingot and average area of macro-grain in this zone. Effect of structure refinement obtained by influence of electromagnetic field was compared with refinement obtained by use of traditional inoculation, which consists in introducing of additives i.e. titanium, boron and carbon to metal bath. The results of studies and their analysis show possibility of effective refinement of pure Al primary structure, only with use of rotating electromagnetic field and without necessity of application of inoculants such a Ti, B and C. This method of inoculation is important, because inoculants decrease the degree of purity and electrical conductivity of pure Al. Moreover Ti and B are reason of point cracks formation during rolling of ingots.
Nature Study of Temperature Phase Transitions in Bitumen Composites with Polymeric Hydrocarbon Plasticizer
Authors: Danchuk V.D. , Kravchuk A.P.
Published: May 2013

In this paper, in terms of stochastic equations theoretically analyzed the influence of the resonance dynamic intermolecular interaction on the formation of spectral vibrational bands of molecular crystals in the transition region to the rotation (plastic) phase. The mechanism that adequately describes the temperature behavior of Davydov splitting intramolecular vibrations value in the normal parrafins crystal phase was offered. This mechanism is associated with damping of vibrational excitons in their interaction with the lattice orientation defects arising from thermal excitation of the librational and rotational degrees of freedom of the molecules. It is shown that one of the factors that determine the appropriate rheological properties of bitumen is the existence in certain temperature ranges rotational phase of hydrocarbon components.
Experiment Study on Stone Masonry Mechanical Properties
Authors: Yang Ling Qiang , Yang Lu Ling , Gao Rui
Published: May 2013

The research presented the mechanical properties under compressive loads of a natural stone masonry. The characterization of the basic materials and different stone masonry prisms are included. Sandstone and low strength lime–cement mortar were used for this experimental work. The morphological characteristics of walls were also taken into account, in order to manufacture prism specimens that were as representative as possible of the Chinese typology. The experimental values were compared with the analytical in different masonry.
Wide-Angle Behaviors of Sub-Wavelength Metal Gratings as Polarizing Beam Splitters
Authors: Li Yun Fang , Xue Chang Xi
Published: May 2013

A second-order effective medium theory (second-order EMT) and thin film theory have been used to design a polarizing beam splitter (PBS) composed of one-dimensional sub-wavelength metal grating, considering the material of metal to be copper (Cu). It was analyzed by the finite difference time domain method for the wavelength of 1500nm. A high extinction ratio in transmission (>55.71dB) over abroad interval of angles of incidence ([-60o, 60o]) is achieved with the depth and the filling factor of the grating chosen to be 350nm and 0.3762, which are selected to transmit TM polarized light and reflect TE polarized light as much as possible at normal incident. The loss of the TE polarized light for the Cu structures is approximately less than 5.55% due to the absorption of Cu in a large angle range. The desired property will enable this type of polarizing beam splitter to be used in diverging beams. When the PBS needs to transmit approximately 25% of the TE polarized light and as much as possible the TM polarized light, it can be used in magneto-optical data storage head. But the depth of grating has been changed (approximately d=40nm) and TM transmission is only 94.7%. But it can be further improved (from 94.7% to 97.97%) by etching into the substrate.
Process Prediction for Low-Energy Ion Beam Figuring Based on BH Modified Model
Authors: Wang Zhi Chao , Yu Hua Dong , Wang Da Seng , Wang Chun Yang
Published: May 2013

Ultra-smooth optical surfaces are very important in widely fields. They’re not only used in optics, but also in the electronics. Ultra-smooth surfaces are difficult to process, because the rms is less than 1nm. The process methods have Teflon Polishing, Float Polishing (FP), Magnetorheological Finishing (MRF) and Ion Beam Figuring (IBF) etc. Compared with conventional polishing, IBF have higher processing quality and efficiency. Low-energy (<2Kev) IBF can form the self-organized nanopatterns on optical surfaces. Since IBF is a non-contact method; there is no edge effect during the process. We can change the ion beam parameters to get dot or ripple pattern on substrate. Only the self-organized ripple pattern is discussed in the paper. For the prediction of process parameters, the principle theories Sigmund theory and BH model are used the interplay between the angle of ion beam incidence, ion flux, incident energy and substrate temperature leads to the self-assembly, which are considered by these theory. In this paper the angle of incidence and incident energy are mainly researched on. Processing nanopatterns on Si has been simulated by SRIM program with these theory and the results reveal several laws in the process. It is believed that these laws will help us to well predict the ion beam parameters and lead IBE experiments.
New Large-Size Three-Dimensional Optical Measuring System Investigation
Authors: Wang Jin Song , Liu Jian , Li Li Juan , Liu Shan , An Zhi Yong
Published: May 2013

In this paper a new three-dimensional large-size optical measurement system by laser radar has been proposed in combination of double-optic circuit measuring technology, ultra-high frequency modulation technology and laser intellectual tracing and location technology. The system can measure 3d shape unconnectedly for lager-size object, which has the advantages of high accuracy, automatic measurement and freedom from being influenced by material and light ray.
Optical System Design of High-Precision Static Star Simulator
Authors: Tao Xue , Zhang Guo Yu , Wu Qiong , Sun Ming Jiao
Published: May 2013

In order to satisfy the high－precision technical requirements of static star simulator, according to the optical design characteristics of traditional star simulator, the paper designed a collimating objective optical system with little distortion, flat field apochromatism, made the simulated star chart by parallel light exit, on the entrance of star sensor produced star chart, and realized the static star simulator could simulate star accuracy static star simulator. This system is designed by four lenses, effective aperture is 20mm, and focal distance is 190.84mm. By imaging quality analysis it shows that in the angular field of view 6°×6°, the relative distortion of collimating objective optical system is less than 0.01%, MTF at 40lp/mm reached 0.6, and has higher imaging quality. It proves that the optical system meet the design requirements.
Optical Correlation Recognition Technology of Small Moving Target Based on Wavelet Multi-Scale Edge Fusion
Authors: Zhang Su , Zhang Qi Bo , Wang You Jian , Wang Wen Sheng
Published: May 2013

Moving target recognition has a wide application in varieties of domains and has received more attention in recent years. Among all the recognition methods, optical correlation technology, using hybrid optoelectronic joint transform correlator (HOJTC), has the merits of parallel, large capacity and high-speed, so it is considered as one of the most effective methods for moving target detection. But in the course of detecting, some targets are too small to be recognized by HOJTC. These small targets in cluttered background and strong noise may affect the brightness of the correlation peaks and have a serious influence on target recognition results. In order to solve this problem, this paper applies a wavelet multi-scale edge fusion algorithm which firstly extracts the edge at different scales by wavelet modulus maximum method, and then fuses the detected edge to obtain more edge information of the target. In addition, for the moving distortion problems, taking temporal state of the target as the template can achieve the template update. To prove this method, many detection experiments of small moving targets have been performed with optical correlation method. As an example a small target “boat” taking up only pixels is presented. The recognition results show that the brightness of the correlation peaks is enhanced and the target recognition ratio is increased. The conclusion can be drawn that applying this algorithm in optical correlation method can realize the small moving target recognition successfully and expand the application to scope of optical correlation technology.
Opto-Mechanical Structure Design of the Image Stabilization Collimator
Authors: Zheng Yang , Fu Yue Gang , He Wen Jun , Wang Jia Ke , Zhang Lei
Published: May 2013

The collimator has an extensive application as an experiment equipment that can provide an infinity goal in the instrument alignment and testing.This paper provides a new type of collimator with image stabilization function in consideration of human disturbance factors, including environment micro-vibration and so on. Liquid surface which appears natural level under gravity imaging optical path of collimator can emerge through liquid refraction and reflex later. And we should make use of this phenomenon. Mathematical modeling and analysis on the principle of dynamic imaging of the liquid wedge have been made to design several optical principle charts of the collimator with image stabilization function.One of the image stabilization optical principle structure styles has been designed based on its mechanical structure.An experiment prototype is produced and is made more practical.
Graded Multilayered TiO2 Photoelectrode for Improving the Performance of Dye Solar Cells
Authors: Samsudin Adel Eskandar , Norani Muti Mohamed
Published: May 2013

Numerous research have been conducted to improve the efficiency of dye solar cell (DSC) through the study on its components namely the dye, electrolyte, counter electrode and the photoelectrode material. This paper presents the study on the usage of a multilayered structure with different composition of TiO2 nanoparticles/aggregates composites starting with the top layer consisting of purely aggregates and ending with the bottom layer consisting of wholly nanoparticles as the photoelectrode material. The graded composition profile of increasing amount of aggregates at the top of the photoelectrode and increasing amount of nanoparticles at the bottom of the photoelectrode will allow for the enhancement in the optical properties and kinetics of DSC. The layers were screen-printed onto FTO coated glass substrate to form the photoelectrodewith an active area of 1 cm2 and thickness of 12 µm. The N719 dye-coated TiO2 electrode was then assembled into sandwich configuration with platinized conducting glass electrode and injected with iodide/tri-iodide redox couples electrolyte.Kinetics and the underlying transport properties of the assembled DSCs were measured by Electrochemical Impedance Spectroscopy (EIS). The response of the cells towards a spectrum of light frequencies was measured using Incident Photon to Electron Conversion Efficiency (IPCE). Conversion efficiency was measured using a 100 mW/cm2 solar simulator. Highest efficiency was found for the multilayered photoelectrode configuration at 4.58% with 14% improvement over the DSC with pure aggregate.DSCs with the multilayered composite configuration have higher current density, Jscwith an increase of 2.249 mA cm-1 compared to the one with only nanoparticles and only aggregates layer. Multilayer configuration has shown significant improvement in the quantum efficiency by exhibiting higher light absorption especially in the range of 500-550 nm light wavelength by about 12.9%.The increase in the conversion efficiency of DSCs with multilayer configuration is also attributed to the improvement in the electron diffusion as evident by the EIS measurement.
Elucidating the Dependence of Size and Concentration of Gold Nanoparticles in Cellular Uptake
Authors: Rosli Nur Shafawati , Abdul Rahman Azhar , Aziz Azlan Abdul
Published: May 2013

Nanoscale particles of gold nowadays dominate a great deal of attention for biomedical applications. Better knowledge of the nano-bio interface will lead to advanced biomedical tools for diagnostic imaging and therapeutics. In this review, recent progress in the elucidating of how size and concentration of gold nanoparticles (AuNPs) affect cellular uptake will be discussed. Due to its small size, AuNPs can be administered conveniently via intravenous injection. The ability to enter cells is one of the factors that determine the clinical utility of nanoparti¬cles (NPs). The size of AuNPs is one of the limitations in the potential use of gold markers for medical imaging or tracking of harder tumors. Within the size range of 10-100 nm, AuNPs of diameter 50 nm demonstrate the highest uptake. Efficient accumulation of AuNPs into cells also can be achieved at higher concentration. The fewer AuNPs are in the solution, the lesser chance for a receptor to receive gold nanoparticle; “mem¬brane wrapping” time is longer, resulting to lower uptake by the cell. Theoretical models support the size- and concentration-dependent NP-uptake. Endocytosis is one of the major pathways for cellular uptake of NPs. NPs are internalized by cells through endocytosis process and trapped in endosomes, which is then fuse with lysosomes for processing before being transported to the cell periphery for excretion. Exocytosis of NPs is also dependent on the size and concentration of the NPs, however, the trend is different compared to endocytosis process. These findings provide useful information in the design and optimization of the NP-uptake at a single cell level for effective applications in imaging, diagnosis, therapeutics, and targeting.
Nanofibers - A Simple and Practical Way Forward for Air Pollution Abatement
Authors: Shahzad Naeem , Chen Qiao
Published: May 2013

Nanofibers have proved to be highly efficient due to their enhanced adsorption capacity, because of high pores and very high surfacearea. Pure and Sulphur doped TiO2nanofibers were synthesized using electrospinning method in this study to evaluate their destruction potential for H2S gas, using photocatalysis. Experiments were carried out under laboratory conditions using capillary glass tube reactor under UV light. 97% destruction was achieved using pure TiO2nanofibers while the destruction percentage decreased when S-doped TiO2nanofibers were replaced with the pure ones. Characterization of the nanofibers before and after running the experiments was carried out using XRD, SEM and EDX techniques. The destruction of H2S gas was measured in ppm using BioGas Analyser fitted with GPA1.8 Gas pod for H2S detection.
Effect of Heat Treatment on Microstructure and Magnetic Properties of Strontium Hexaferrite Nanoparticles Prepared in Presence of Non-Ionic Surfactant
Authors: Panchal Nital R. , Jotania Rajshree B.
Published: May 2013

SrFe12O19 hexaferrite particles containing polyoxyethelene (20) sorbitan monolate (Tween-80) were synthesized by a chemical co-precipitation technique with a precipitator NH3.H2O. The prepared Sr-M hexaferrite precipitates were heat treated at various temperatures 650 oC, 750 oC, 850 oC, 950oC and 1100oC for 4 hrs in a muffle furnace. The obtained Sr-M powders were characterized by using various instrumental techniques, like FTIR, TGA, XRD, SEM, VSM and Mössbauer spectroscopy. Their physical as well as Magnetic properties were compared. It was observed from XRD results that heat treatment conditions play significant role in the formation of pure SrFe12O19 hexaferrite phase and also in the grain size. The estimated particle size is of the order of nanometer when suitable calcination temperature is applied. SEM micrographs show an increase in crystallite size of the resultant SrFe12O19 hexaferrite particles sintered at higher temperature (1100 oC). Mössbauer spectroscopic measurements were carried out at room temperature. Mössbauer analysis indicates the presence Fe3+ ions in the prepared strontium hexaferrite particles.
Performance of endoscopic ultrasound-guided fine needle aspiration in diagnosing pancreatic neuroendocrine tumors
Authors: Bernstein Jane , Ustun Berrin , Alomari Ahmed , Bao Fang , Aslanian Harry R. , Siddiqui Uzma , Chhieng David , Cai Guoping
Published: May 2013

Background:

Pancreatic neuroendocrine tumors (PNETs) are rare tumors of the pancreas, which are increasingly diagnosed by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). In this retrospective study, we assessed the performance of EUS-FNA in diagnosing PNETs.

Materials and Methods:

We identified 48 cases of surgically resected PNETs in which pre-operative EUS-FNA was performed. The clinical features, cytological diagnoses, and surgical follow-up were retrospectively reviewed. The diagnostic performance of EUS-FNA was analyzed as compared to the diagnosis in the follow-up. The cases with discrepancies between cytological diagnosis and surgical follow-up were analyzed and diagnostic pitfalls in discrepant cases were discussed.

Results:

The patients were 20 male and 28 female with ages ranging from 15 years to 81 years (mean 57 years). The tumors were solid and cystic in 41 and 7 cases, respectively, with sizes ranging from 0.5 cm to 11 cm (mean 2.7 cm). Based on cytomorphologic features and adjunct immunocytochemistry results, when performed, 38 patients (79%) were diagnosed with PNET, while a diagnosis of suspicious for PNET or a diagnosis of neoplasm with differential diagnosis including PNET was rendered in the 3 patients (6%). One case was diagnosed as mucinous cystic neoplasm (2%). The remaining 6 patients (13%) had non-diagnostic, negative or atypical diagnosis.

Conclusions:

Our data demonstrated that EUS-FNA has a relatively high sensitivity for diagnosing PNETs. Lack of additional materials for immunocytochemical studies could lead to a less definite diagnosis. Non-diagnostic or false negative FNA diagnosis can be seen in a limited number of cases, especially in those small sized tumors.
Motion in a Symmetric Potential on the Hyperbolic Plane
Authors: Santoprete Manuele , Scheurle Jürgen , Walcher Sebastian
Published: May 2013

We study the motion of a particle in the hyperbolic plane (embedded in Minkowski space), under the action of a potential that depends only on one variable. This problem is analogous to the spherical pendulum in a unidirectional force field. However, for the discussion of the hyperbolic plane one has to distinguish three inequivalent cases, depending on the direction of the force field. Symmetry reduction, with respect to groups that are not necessarily compact or even reductive, is carried out by way of Poisson varieties and Hilbert maps. For each case the dynamics is discussed, with special attention to linear potentials.
Reductions of Shimura Varieties
Authors: Fargues Laurent , Görtz Ulrich , Viehmann Eva , Wedhorn Torsten
Published: May 2013

The workshop brought together leading experts in the theory of reductions of Shimura varieties. The talks presented new methods and results that intertwine a multitude of topics such as geometry and cohomology of moduli spaces of abelian varieties, p-divisible groups and Drinfeld shtukas,

p

-adic Hodge theory, arithmetic intersections of cycles on Shimura varieties, Bruhat-Tits buildings, and

p

-adic automorphic forms.
Calculus of Variations
Authors: De Lellis Camillo , Huisken Gerhard , Jerrard Robert L.
Published: May 2013

Since its invention, the calculus of variations has been a central field of mathematics and physics, providing tools and techniques to study problems in geometry, physics and partial differential equations. On the one hand, steady progress is made on long-standing questions concerning minimal surfaces, curvature flows and related objects. On the other hand, new questions emerge, driven by applications to diverse areas of mathematics and science. The July 2012 Oberwolfach workshop on the Calculus of Variations witnessed the solutions of famous conjectures and the emerging of exciting new lines of research.
Clinco-Epidemiologic Study of Cutaneous Leishmaniasis in Bikaner, Rajasthan, India
Authors: Aara Naushin , Khandelwal Kanika , Bumb Ram A. , Mehta Rajesh D. , Ghiya Bhikam C. , Jakhar Renu , Dodd Claire , Salotra Poonam , Satoskar Abhay R.
Published: May 2013

Cutaneous leishmaniasis is endemic to the Thar Desert of Rajasthan, Bikaner, India. The present study describes clinico-epidemiologcial data of all cases of cutaneous leishmaniasis CL in this region during 2001–2011. A total of 1,379 patients with 2,730 lesions were reported during the study period. Ages of patients ranged from 3 months to 86 years, and there was a predominance of infections in males. Most patients were from urban areas and lower middle socioeconomic groups. Lesions were dry, ulcerated nodules or plaques of different sizes commonly over face and upper limb. Skin smears were positive for parasites in 958 (69.5%) patients, and the remaining 45.8% (193 of 421) patients were positive by skin biopsy. Histopathologic analysis of the skin showed mixed granulomas consisting of macrophages, lymphocytes, epitheloid, and plasma cells. Species identification was conducted for 45 randomly selected patients by polymerase chain reaction, the infective species was Leishmania tropica. Most patients were treated with intra-lesional injections of sodium stibogluconate.
H2S as an Indicator of Water Supply Vulnerability and Health Risk in Low-Resource Settings: A Prospective Cohort Study
Authors: Khush Ranjiv S. , Arnold Benjamin F. , Srikanth Padma , Sudharsanam Suchithra , Ramaswamy Padmavathi , Durairaj Natesan , London Alicia G. , Ramaprabha Prabhakar , Rajkumar Paramasivan , Balakrishnan Kalpana , Colford John M.
Published: May 2013

In this large-scale longitudinal study conducted in rural Southern India, we compared a presence/absence hydrogen sulfide (H2S) test with quantitative assays for total coliforms and Escherichia coli as measures of water quality, health risk, and water supply vulnerability to microbial contamination. None of the three indicators showed a significant association with child diarrhea. The presence of H2S in a water sample was associated with higher levels of total coliform species that may have included E. coli but that were not restricted to E. coli. In addition, we observed a strong relationship between the percent positive H2S test results and total coliform levels among water source samples (R2 = 0.87). The consistent relationships between H2S and total coliform levels indicate that presence/absence of H2S tests provide a cost-effective option for assessing both the vulnerability of water supplies to microbial contamination and the results of water quality management and risk mitigation efforts.
Performance of the Tourniquet Test for Diagnosing Dengue in Peru
Authors: Halsey Eric S. , Vilcarromero Stalin , Forshey Brett M. , Rocha Claudio , Bazan Isabel , Stoddard Steven T. , Kochel Tadeusz J. , Casapia Martin , Scott Thomas W. , Morrison Amy C.
Published: May 2013

The tourniquet test (TT) is a physical examination maneuver often performed on patients suspected of having dengue. It has been incorporated into dengue diagnostic guidelines and is used in clinical studies. However, little is known about TT performance characteristics in different patient types or epidemiologic conditions. In the dengue-endemic city of Iquitos, Peru, we performed TTs and dengue laboratory assays on 13,548 persons with febrile disease, recruited through either active (n = 1,095) or passive (n = 12,453) surveillance. The sensitivity was 52% and 56%, the specificity was 58% and 68%, the positive predictive value was 45% and 55%, and the negative predictive value was 64% and 69% for persons enrolled in active and passive surveillance, respectively. We demonstrated that the TT was more sensitive identifying dengue disease in women and those of younger age and that sensitivity increased the later a person came to a medical clinic for care.
Multi‐Market Competition, R&D, and Welfare in Oligopoly
Authors: Kawasaki Akio , Lin Ming Hsin , Matsushima Noriaki
Published: May 2013

We investigate a multi‐market Cournot model with strategic process research and development (R&D) investments wherein a multi‐market firm meets new competitors that enter one of the markets. We show that entry can enhance the total R&D expenditures of the multi‐market firm. Moreover, the incumbent's profit nonmonotonically changes as the number of entrants increases. Depending on the fixed entry costs and R&D technologies, both insufficient and excess entry can appear. Our results imply that diversification of their products can be a useful strategy for firms.
Outcomes of Corneal Collagen Cross-linking for Keratoconus the Effect of Cone Location
Authors: Agrawal Vinay
Published: May 2013

Aim

One-year outcome of corneal collagen cross-linking (CXL) for keratoconus with reference to topographic cone location.

Materials and methods

Clinical audit of the results of CXL were used. Three hundred and seventy-eight eyes of 225 patients with preoperative and 12-month completed follow-up were included. Cone location was defined by cone location magnitude index (CLMI) using the Keratron scout topography system. The eyes were divided into two groups–central with cone location within 3 mm zone of the topography map and paracentral with cone location between the 3 and 5 mm zones.

Results

The overall group showed a mean flattening of the CLMI of 1.67 D [preoperative 53.35 ± 5.63 D, 12 months 51.69 ± 4.67 (p = 0.095)]. The flattening in central cone group was 2.67 D [preoperative 54.01 ± 5.3819, at 12 months to 51.341 ± 4.588 (p = 0.016)]. In paracentral cone group the flattening was lesser at 1.73 D [preoperative apex K 52.805 ± 6.382, at 12 months 51.03 ± 4.82 (p = 0.006)]. The difference between groups was statistically significant (p < 0.001). The central cone group showed no significant shift in cone position [preoperative 1.0059 ± 0.24, at 12 months 0.986 ± 0.206 (p = 0.45)]. The paracentral cone group showed a significant mean shift of 1.05 mm in cone location [preoperative 2.224 ± 0.440, at 12 months 1.196 ± 0.529 (p = 0.001)].

Conclusion

Cone location has an impact on the results of corneal cross-linking. The paracentral cones show a significant shift toward the center of the cornea and the central cones show a larger flattening.

How to cite this article

Agrawal V. Outcomes of Corneal Collagen Cross-linking for Keratoconus the Effect of Cone Location. Int J Kerat Ect Cor Dis 2013;2(1):16-19.
Photosynthetic parameters in the Beaufort Sea in relation to the phytoplankton community structure
Authors: Huot Y. , Babin M. , Bruyant F.
Published: May 2013

Abstract. To model phytoplankton primary production from remotely sensed data, a method to estimate photosynthetic parameters describing the photosynthetic rates per unit biomass is required. Variability in these parameters must be related to environmental variables that are measurable remotely. In the Arctic, a limited number of measurements of photosynthetic parameters have been carried out with the concurrent environmental variables needed. Such measurements and their relationship to environmental variables will be required to improve the accuracy of remotely sensed estimates of phytoplankton primary production and our ability to predict future changes. During the MALINA cruise, a large dataset of these parameters was obtained. Together with previously published datasets, we use environmental and trophic variables to provide functional relationships for these parameters. In particular, we describe several specific aspects: the maximum rate of photosynthesis (Pmaxchl) normalized to chlorophyll decreases with depth and is higher for communities composed of large cells; the saturation parameter (Ek) decreases with depth but is independent of the community structure; and the initial slope of the photosynthesis versus irradiance curve (αchl) normalized to chlorophyll is independent of depth but is higher for communities composed of larger cells. The photosynthetic parameters were not influenced by temperature over the range encountered during the cruise (−2 to 8 °C).
Comparison of inorganic nitrogen uptake dynamics following snowmelt and at peak biomass in subalpine grasslands
Authors: Legay N. , Grassein F. , Robson T. M. , Personeni E. , Bataillé M.-P. , Lavorel S. , Clément J.-C.
Published: May 2013

Abstract. Subalpine grasslands are highly seasonal environments and likely subject to strong variability in nitrogen (N) dynamics. Plants and microbes typically compete for N acquisition during the growing season and particularly at plant peak biomass. During snowmelt, plants could potentially benefit from a decrease in competition by microbes because of greater plant N uptake associated with active growth and freeze-thaw cycles restricting microbial growth. In managed subalpine grasslands, we expect these interactions to be influenced by recent changes in agricultural land-use, and associated modifications in plant and microbial communities. At a subalpine grassland site in the Central French Alps, a pulse of 15N was added to the soil at the end of snowmelt, allowing us to compare the dynamics of inorganic N uptake in plants and microbes during this period with that previously reported at the peak biomass in July. In all grasslands, specific plant (per g of biomass) dissolved inorganic N (DIN) uptake was two to five times greater at snow-melt than at peak biomass, whereas the specific microbial DIN uptakes were similar between the two sampling dates. On an area basis, plant communities took more DIN than microbial communities at the end of snowmelt, and the intensity of this DIN uptake by plants differed across land use types. Consequently, N partitioning after snowmelt switches in favor of plant communities allowing them to support their growing capacities at this period of the year. Seasonal differences in microbial and plant N-related dynamics were also affected by past (terraced vs. unterraced) rather than current (mown vs. unmown) land use. In terraced grasslands, microbial biomass N remained similar across seasons, whereas in unterraced grasslands, microbial biomass N was higher and microbial C : N lower at the end of snowmelt as compared to peak biomass. Further investigations on microbial community composition and their organic N uptake dynamics are required to better understand the decrease in microbial DIN uptake.
Abrupt shifts of the Sahara–Sahel boundary during Heinrich stadials
Authors: Collins J. A. , Govin A. , Mulitza S. , Heslop D. , Zabel M. , Hartmann J. , Röhl U. , Wefer G.
Published: May 2013

Abstract. Relict dune fields that are found as far south as 14° N in the modern-day African Sahel are testament to equatorward expansions of the Sahara desert during the Late Pleistocene. However, the discontinuous nature of dune records means that abrupt millennial-timescale climate events are not always resolved. High-resolution marine core studies have identified Heinrich stadials as the dustiest periods of the last glacial in West Africa although the spatial evolution of dust export on millennial timescales has so far not been investigated. We use the major-element composition of four high-resolution marine sediment cores to reconstruct the spatial extent of Saharan-dust versus river-sediment input to the continental margin from West Africa over the last 60 ka. This allows us to map the position of the sediment composition corresponding to the Sahara–Sahel boundary. Our records indicate that the Sahara–Sahel boundary reached its most southerly position (13° N) during Heinrich stadials and hence suggest that these were the periods when the sand dunes formed at 14° N on the continent. Heinrich stadials are associated with cold North Atlantic sea surface temperatures which appear to have triggered abrupt increases of aridity and wind strength in the Sahel. Our study illustrates the influence of the Atlantic meridional overturning circulation on the position of the Sahara–Sahel boundary and on global atmospheric dust loading.
Mid and late Holocene dust deposition in western Europe: the Misten peat bog (Hautes Fagnes – Belgium)
Authors: Allan M. , Le Roux G. , Piotrowska N. , Beghin J. , Javaux E. , Court-Picon M. , Mattielli N. , Verheyden S. , Fagel N.
Published: May 2013

Abstract. Dust deposition in southern Belgium is estimated from the geochemical signature of an ombrotrophic peatland. The Rare Earth Elements (REE) and lithogenic elements concentrations, as well as Nd isotopes, were determined by HR-ICP-MS and MC-ICP-MS respectively, in along a ~6 m peat section covering 5300 yr, from 30 BC to 5300 BC dated by the 14C method. Changes in REE concentration in the peat correlate with those of Ti, Al, Sc and Zr that are lithogenic conservative elements, suggesting that REE are immobile in the studied peat bogs and can be used as tracers of dust deposition. Peat humification and testate amoebae were used to evaluate hydroclimatic conditions. The range of dust deposition varied from 0.03 to 4.0 g m−2 yr−1. The highest dust fluxes were observed from 800 to 600 BC and from 3200 to 2800 BC and correspond to cold periods. The εNd values show a large variability of −5 to −13, identifying three major sources of dusts: local soils, distal volcanic and desert particles.
Socio-hydrology and the science-policy interface: a case study of the Saskatchewan River Basin
Authors: Gober P. , Wheater H. S.
Published: May 2013

Abstract. While there is popular perception that Canada is a water-rich country, the Saskatchewan River Basin (SRB) in Western Canada exemplifies the multiple threats to water security seen worldwide. It is Canada's major food-producing region and home to globally-significant natural resource development. The SRB faces current water challenges stemming from: (1) a series of extreme events, including major flood and drought events, since the turn of the 21st century, (2) full allocation of existing water resources in parts of the Basin, (3) rapid population growth and economic development, (4) increasing pollution, and (5) fragmented governance that includes the Provinces of Alberta, Saskatchewan, and Manitoba, various Federal and First Nations responsibilities, and international boundaries. The interplay of these factors has increased competition for increasingly scarce water resources across economic sectors and among provinces, between upstream and downstream users, between environmental flows and human needs, and among people who hold different values about the meaning, ownership, and use of water. These current challenges are set in a context of significant environmental and societal change, including widespread land modification, climate warming, and deep uncertainties about future water supplies. We outline the geographic setting of the SRB and its environmental history, and then discuss the major challenges to water security from: (1) environmental change, (2) rapid growth and economic development, and most importantly, (3) a governance model unsuited to managing complex and uncertain water systems. We conclude with a discussion of the emerging field of socio-hydrology and what it can contribute to knowledge translation, water management, policy, and governance in the SRB and worldwide.
Review article: Assessing the costs of natural hazards – state of the art and knowledge gaps
Authors: Meyer V. , Becker N. , Markantonis V. , Schwarze R. , van den Bergh J. C. J. M. , Bouwer L. M. , Bubeck P. , Ciavola P. , Genovese E. , Green C. , Hallegatte S. , Kreibich H. , Lequeux Q. , Logar I. , Papyrakis E. , Pfurtscheller C. , Poussin J. , Przyluski V. , Thieken A. H. , Viavattene C.
Published: May 2013

Abstract. Efficiently reducing natural hazard risks requires a thorough understanding of the costs of natural hazards. Current methods to assess these costs employ a variety of terminologies and approaches for different types of natural hazards and different impacted sectors. This may impede efforts to ascertain comprehensive and comparable cost figures. In order to strengthen the role of cost assessments in the development of integrated natural hazard management, a review of existing cost assessment approaches was undertaken. This review considers droughts, floods, coastal and Alpine hazards, and examines different cost types, namely direct tangible damages, losses due to business interruption, indirect damages, intangible effects, and the costs of risk mitigation. This paper provides an overview of the state-of-the-art cost assessment approaches and discusses key knowledge gaps. It shows that the application of cost assessments in practice is often incomplete and biased, as direct costs receive a relatively large amount of attention, while intangible and indirect effects are rarely considered. Furthermore, all parts of cost assessment entail considerable uncertainties due to insufficient or highly aggregated data sources, along with a lack of knowledge about the processes leading to damage and thus the appropriate models required. Recommendations are provided on how to reduce or handle these uncertainties by improving data sources and cost assessment methods. Further recommendations address how risk dynamics due to climate and socio-economic change can be better considered, how costs are distributed and risks transferred, and in what ways cost assessment can function as part of decision support.
Cementless Bipolar Hemiarthroplasty Using a Rectangular Cross-Section Stem for Unstable Intertrochanteric Fractures
Authors: Park Myung-Sik , Cho Hong-Man , Kim Ju-Han , Shin Woo-Jin
Published: May 2013

The purpose of this study was to compare the clinical and radiographic results for elderly patients sustaining unstable intertrochanteric fractures treated with an uncemented bipolar hemiarthroplasty using a double-tapered, rectangular cross-section stem.

Thirty-seven patients (21 females, 16 males; mean age 73.5 years, range 65-88 years) who underwent bipolar hemiarthroplasty with a standard (double-tapered, rectangular cross-section) uncemented stem were followed up for a minimum of two years. At final follow-up, 27 patients (72.9%) had recovered their daily living ability (Barthel index), and 28 patients (75.6%) had recovered all walking ability at a community level (Koval's category).
Heparin-induced thrombocytopenia associated with thrombotic microangiopathy
Authors: Binet I. , Nair G. , Schanz U. , Studt J.-D.
Published: May 2013

Some cases of thrombotic microangiopathy (TMA) are refractory to plasma exchange therapy (PE) with persistence or recurrence of thrombocytopenia. We report two patients suffering from TMA of different aetiologies (associated with disseminated malignancy, typical haemolytic uraemic syndrome) with recurrent or persistent thrombocytopenia despite adequate therapy including PE. Since both patients were exposed to unfractionated heparin, heparin-induced thrombocytopenia (HIT) was suspected as a cause. Pretest probabilities for HIT were intermediate. ELISA for PF4/heparin antibodies was strongly positive in both cases, and HIT was confirmed by heparin-induced platelet activation assay. Anticoagulation with lepirudin was initiated, with subsequent rapid increase of the platelet count.

TMA might represent a predisposition for HIT. This could be due to TMA-related platelet activation with increased PF4 release. In TMA patients exposed to heparin and with refractory or rapidly recurrent thrombocytopenia HIT should always be considered as a possible cause.
The effect of mangroves amendments to soil on root rot and root knot of potato (Solanum tuberosum L.)
Authors: Tariq Marium , Dawar Shahnaz , Mehdi Fatima S. , Zaki Muhammad J.
Published: May 2013

Leaves, stem and pneumatophore of Avicennia marina and leaves and stem of Rhizophora mucronata were used as the organic amendments at 0.1, 1 and 5% concentrations in the control of root rot fungi like (Fusarium spp., Rhizoctonia solani and Macrophomina phasoelina) and root knot nematode Meloidogyne javanica on potato. In pot experiments, germination of seeds, shoot length, shoot weight, root length, root weight and number of knots were significantly increased when plant parts like leaves, stem and pneumatophore of A. marina and R. mucronata were used at 1 and 5% concentrations. There was a complete suppression in infection of R. solani and M. phaseolina when A. marina and R. mucronata were used at 5% concentration on potato. Maximum inhibition of knots of M. javanica was observed when powder made from mangrove plant parts was used at 1 and 5% concentrations. Powder from all plant parts, like leaves, stem and pneumatophore, was effective in suppression of root infecting fungi and root knot nematode.