bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of the eye of the Indian mongoose (Herpestes auropunctatus)
Authors: Nellis D. W. , Sivak J. G. , McFarland W. N. , Howland H. C.
Published: March 2009

The refractive state, optical structure, and intraocular muscles of the eye of the Indian mongoose, Herpestes auropunctatus, were examined using a variety of refractive and anatomical techniques. Additional observations concern the structure and function of the tapetum lucidum and the diurnal activity levels. The mongoose eye is emmetropic (zero refractive error), or nearly so, a surprising finding in view of the small (8.0 mm diameter) size of the eye and the fact that the small-eyed mammals seem to show varying degrees of apparent hyperopia. The optical media, particularly the size, shape, and relative location of the ocular lens, are those of a diurnal species. Accommodation, induced pharmacologically, is of a magnitude (11–13.5 diopters) normally associated with primates. The ciliary muscle consists of large and well-developed fascicles of longitudinal fibres. The iris muscles, especially the sphincter, are much larger, on a relative basis, than those of the human iris. The mongoose eye is characterized by the existence of an obvious bright green tapetum cellulosum located in the choroid. The spectral quality of the tapetal reflection matches spectral radiometric measures made in grasses that the animal inhabits. Activity observations confirm the strict diurnality of the mongoose. Though a tapetum is normally associated with nocturnal vision, the mongoose tapetum may be of use in ensuring that the light reflected by the dense vegetation and incident to the eye stimulates cones with relatively high stimulus thresholds.
Notes on fruit bats (Chiroptera, Pteropodidae) from Malaysia and Brunei, with the description of a new subspecies of Megaerops wetmorei Taylor, 1934
Authors: Francis Charles M.
Published: March 2009

New specimens of several poorly known Malaysian fruit bats are described. Megaerops wetmorei albicollis subsp.nov. is reported from peninsular Malaysia and Brunei. It differs from the nominate Philippine subspecies in having large white tufts on the sides of the neck and a relatively shorter, higher rostrum. Further specimens of Chironax melanocephalus from Borneo confirm the allocation of this population to the nominate subspecies. Observations of live Rousettus spinalatus show that the wings are joined over the middle of the back, and suggest that this species echolocates in a similar fashion to Rousettus amplexicaudatus.
The interaction between carbon dioxide and ammonia excretion and water pH in fish
Authors: Randall D. J. , Wright P. A.
Published: March 2009

The pH of plasma is midway between the pK of the [Formula: see text] and [Formula: see text] reactions. Carbon dioxide excretion across the gill acidifies the water, as CO2 hydrates to form [Formula: see text] and H+ ions. The hydration reaction is catalyzed by carbonic anhydrase in the water boundary layer next to the gills and on the gill epithelium. Acidification of the boundary layer is greater than in the bulk flow, particularly in water of high pH and low buffering capacity. Ammonia excretion will raise water pH but this effect is usually masked by the much larger CO2 excretion. At low water pH, below the pK′ of the CO2 hydration reaction, little [Formula: see text] and H+ will be formed, therefore CO2 will have little effect on downstream water pH. Under these conditions, NH3 excretion will alkalinize water as it passes over the gills. Formation of an acid gill water boundary layer as a result of CO2 excretion will trap NH3 as [Formula: see text] and enhance ammonia transfer. Removal of the acid boundary layer, either by increasing the buffering capacity of the water or by reducing CO2 excretion, decreases ammonia transfer in the isolated head of rainbow trout. Water pH can have a marked effect on CO2 and NH3 gradients across the gills. In alkaline waters, the rise in blood NH3 levels will result in a marked increase in body stores of total ammonia. Tilapia (Oreochromis alcalicus grahami) in Lake Magadi, Kenya, at a water pH of 10, excrete nitrogenous wastes as urea, to avoid the problem of the buildup of toxic levels of ammonia when the fish are exposed to these alkaline conditions.
Mechanisms of ventilation in lower vertebrates: adaptations to respiratory and nonrespiratory constraints
Authors: Milsom William K.
Published: March 2009

The design of vertebrate respiratory systems has been subject to two major sets of constraints. The first is the need to satisfy the primary function of the respiratory surface as an organ of gas exchange. These constraints include the need to reduce the diffusion gradient between air and blood while providing adequate ventilation and perfusion of the exchange surface. The second set of constraints arises from the need to satisfy other physiological, environmental, and behavioral demands. The constraints imposed by the low oxygen content and high density of water as a respiratory medium, the rigid shell of turtles, and the long thin body of snakes, as well as the life-style and habitat of diving animals, are all used to illustrate the unique features of several experiments in the design and performance of respiratory pumps. It is shown, however, that despite the tremendous diversity that exists among species, all mechanisms allow ventilation to be powered by surprisingly similar changes in pulmonary pressure.
Respiratory pigments: interactions between oxygen and carbon dioxide transport
Authors: Bridges C. R. , Morris S.
Published: March 2009

Oxygen and carbon dioxide are transported in vertebrates and invertebrates by a wide range of respiratory pigments. These respiratory gases are not transported independently of one another, and this review considers the influence of carbon dioxide on oxygen transport and vice versa. A specific effect of carbon dioxide or bicarbonate, decreasing oxygen affinity, is found in many haemoglobins, but the effect is often reduced in the presence of organic phosphates. Clear experimental data are available for mammalian haemoglobins but in birds and lower vertebrates more data are required to verify the presence and magnitude of the CO2 effect. In erythrocruorins and haemocyanins CO2 increases O2 affinity, whereas in haemerythrins, as in haemoglobin, CO2 again decreases oxygen affinity. Much of our knowledge of invertebrate respiratory pigments is based, however, on data from one or two species. A specific effect of CO2 on O2 affinity has also often been found only at high CO2 partial pressures, which may be outside the physiological range for these species. More in vivo experimental data on CO2 values are required for these species, and further studies on other species may help to explain this discrepancy. The interaction of O2 and CO2 transport is mainly through the Haldane effect, i.e., deoxygenated blood having a greater capacity for CO2 than oxygenated blood. This is due directly to the formation of carbamino groups (carbamate) and also to the fact that deoxygenated blood binds relatively more protons than oxygenated blood. This forms the basis for the linkage between the Bohr and Haldane effects. In some species in which the Bohr coefficient is below −1.0, an akalosis in the tissues may be induced. Large Haldane effects may be particularly effective in promoting CO2 unloading when the partial pressure difference of CO2 between arterial and venous blood is small. Carbamate formation may account for 10–20% of the CO2 transported in mammals, but its role in lower vertebrates and invertebrates has only recently been considered. Carbon dioxide transport is modulated by those factors that influence O2 affinity as these in turn influence the Haldane effect.
Interactions between cutaneous ion-exchange mechanisms and acid–base balance in amphibians
Authors: Stiffler Daniel F.
Published: March 2009

It has been suspected for over 50 years that amphibian ion exchange involves independent transport of Na+ and Cl− in an inward direction across the skin in exchange for acidic cations and basic anions, respectively. Although a role for such exchange mechanisms has obvious utility in acid–base balance, their participation in this homeostatic process has only recently been documented. We now know that in aquatic Ambystoma tigrinum, the presence of NaCl in the water bathing the skin is required for acid–base regulatory responses to hypercapnia and exercise-induced lactacidosis. Acidotic and alkalotic conditions in the animals' extracellular fluid cause changes in both Na+ and Cl− influx and net flux which are consistent with a role for ion transport in acid–base balance. These processes appear to be under the control of both catecholamines and interrenal steroids.
Compromises between ionic regulation and acid–base regulation in aquatic animals
Authors: Cameron James N. , Iwama George K.
Published: March 2009

To compensate for various sorts of acid–base disturbances, animals must sometimes make large changes in the concentration of [Formula: see text] in both intra- and extra-cellular fluids. As [Formula: see text] concentration is dependent upon several other solution parameters, including the so-called strong ions, there must often be compromises between compensation of acid–base disturbances and the requirements for ionic and osmotic homeostasis. Data showing that partial compensation of hypercapnia may represent such a compromise have been gathered from both fish and crabs. Traditional approches to acid–base regulation emphasize the [Formula: see text] system changes, but more recently an approach based on electrolytes has been promoted. The similarities between these two approaches are illustrated with experimental data and theoretical studies. Practical limitations prevent the routine use of the electrolyte (strong ion) approach.
FATIGUE LIFE PREDICTION OF ROLLED AZ31 MAGNESIUM ALLOY USING AN ENERGY-BASED MODEL
Authors: PARK SUNG HYUK , HONG SEONG-GU , LEE BYOUNG HO , LEE CHONG SOO
Published: March 2009

Fatigue behavior of rolled AZ31 magnesium alloy, which shows an anisotropic deformation behavior due to the direction dependent formation of deformation twins, was investigated by carrying out stress and strain controlled fatigue tests. The anisotropy in deformation behavior introduced asymmetric stress-strain hysteresis hoops, which make it difficult to use common fatigue life prediction models, such as stress and strain-based models, and induced mean stress and/or strain even under fully-reversed conditions; the tensile mean stress and strain were found to have a harmful effect on the fatigue resistance. An energy-based model was used to describe the fatigue life behavior as strain energy density was stabilized at the early stage of fatigue life and nearly invariant through entire life. To account for the mean stress and strain effects, an elastic energy related to the mean stress and a plastic strain energy consumed by the mean strain were appropriately considered in the model. The results showed that there is good agreement between the prediction and the experimental data.
APPLICATION OF FORMING LIMIT CRITERIA BASED ON PLASTIC INSTABILITY CONDITION TO METAL FORMING PROCESS
Authors: HEO SEONG-CHAN , KU TAE-WAN , KIM JEONG , KANG BEOM-SOO , SONG WOO-JIN
Published: March 2009

Metal forming processes such as hydroforming and sheet metal forming using tubular material and thin sheet metal have been widely used in lots of industrial fields for manufacturing of various parts that could be equipped with mechanical products. However, it is not easy to design sequential processes properly because there are various design variables that affect formability of the parts. Therefore preliminary evaluation of formability for the given process should be carried out to minimize time consumption and development cost. With the advances in finite element analysis technique over the decades, the formability evaluation using numerical simulation has been conducted in view of strain distribution and final shape. In this paper, the application of forming limit criteria is carried out for the tube hydroforming and sheet metal forming processes using theoretical background based on plastic instability conditions. Consequently, it is confirmed that the local necking and diffuse necking criteria of sheet are suitable for formability evaluation of both hydroforming and sheet metal forming processes.
EFFECT OF ASYMMETRICAL STAND STIFFNESS ON HOT ROLLED STRIP SHAPE
Authors: GONG DIANYAO , XU JIANZHONG , JIANG ZHENGYI , ZHANG XIAOMING , LIU XIANGHUA , WANG GUODONG
Published: March 2009

The difference of elastic springs between the operating side (OS) and driving side (DS) of rolling mill has a significant influence on the strip shape not just the strip thickness. Based on the slit beam and roll deformation theories, the roll force distribution was analysed considering the asymmetric stiffness of the OS and DS of rolling mill, and the work roll and backup roll deformation equations were deduced respectively, and the thickness distribution in lateral direction of the hot rolled strip at exit was discussed. Using the roll elastic deformation analysis software which was developed previously based on the influence coefficient method, the roll flattening distribution, roll pressure distribution and the rolling force distribution caused by the asymmetric stand stiffness were calculated and analysed, and the exit strip profile of the rolling mill was also presented. The relationship between the mill stiffness difference and the strip wedge shape or single wave was obtained. Effect of the upstream asymmetric mill on strip crown and flatness of the downstream stands was discussed.
STRETCHING-INDUCED ORIENTATION TO IMPROVE MECHANICAL PROPERTIES OF ELECTROSPUN PAN NANOCOMPOSITES
Authors: HOU X. X. , YANG X. P. , ZHANG F. , WU S. Z. , WACLAWIK E.
Published: March 2009

Partially aligned and oriented polyacrylonitrile(PAN)-based nanofibers were electrospun from PAN and SWNTs/PAN in the solution of dimethylformamide(DMF) to make the carbon nanofibers. The as-spun nanofibers were hot-stretched in an oven to enhance its orientation and crystallinity. Then it were stabilized at 250 °C under a stretched stress, and carbonized at 1000 °C in N 2 atmosphere by fixing the length of the stabilized nanofiber to convert them into carbon nanofibers. With this hot-stretched process and with the introduction of SWNTs, the mechanical properties will be enhanced correspondingly. The crystallinity of the stretched fibers confirmed by X-ray diffraction has also increased. For PAN nanofibers, the improved fiber alignment and crystallinity resulted in the increased mechanical properties, such as the modulus and tensile strength of the nanofibers. It was concluded that the hot-stretched nanofiber and the SWNTs/PAN nanofibers can be used as a potential precursor to produce high-performance carbon composites.
THE BENDABILITY AND FORMABILITY OF COLD ROLLED AND HEAT TREATED AZ31 MG ALLOY SHEETS
Authors: KIM INSOO , AKRAMOV SAIDMUROD
Published: March 2009

In this study, strong {0002} textured (or strong ND//<0002> textured) AZ31 Mg alloy sheets were prepared. These AZ31 Mg alloy sheets were cut along the angles of 0, 12.5, 25, 30 and 37.5 degrees to the rolling direction or {0002} texture. Prepared samples with different angles to the rolling direction were rolled at room temperature and after subsequent heat treatment, the bendability, ultimate tensile stress, elongation and texture are investigated using the 3-points bending tester, tensile tester and x-ray diffractometer, respectively. The specimen having along the angles of 0 degree to the rolling direction shows the highest load and 45 degrees specimen shows the highest displacement among any other specimens in the bending test. The specimen having along the angles of 12.5 and 25 degrees to the rolling direction shows highest elongation and of 0 degree specimen shows the highest ultimate tensile stress among any other specimens after cold rolling and subsequent heat treatment at 150°C for 30 minutes in bending test.
GRAIN-SIZE DEPENDENT YIELD BEHAVIOR UNDER LOADING, UNLOADING AND REVERSE LOADING
Authors: OHNO NOBUTADA , OKUMURA DAI , SHIBATA TOMOYUKI
Published: March 2009

Two types of higher-order stresses work-conjugate to slip gradient in single crystals are investigated to analyze the grain-size dependent yield behavior of polycrystals. The first is the higher-order stress due to the self-energy of geometrically necessary dislocations (GNDs). The second higher-order stress examined is an extension based on the non-recoverable energy that is postulated to be proportional to the accumulated density of incrementally defined GNDs. It is shown that the second higher-order stress is co-directional with the in-plane gradient of slip-rate and consequently causes isotropic hardening, whereas the first higher-order stress is co-directional with the in-plane gradient of slip. These higher-order stresses are incorporated into a strain gradient plasticity theory of single crystals. Subsequently, using a finite element method, 2D model polycrystals are analyzed to demonstrate the influence of the two types of higher-order stresses on the grain-size dependent yield behavior under loading, unloading and reverse loading.
EBSD STUDY ON THE EVOLUTION OF MICROSTRUCTURES DURING COMPRESSIVE DEFORMATION OF AN AUSTENITIC STAINLESS STEEL
Authors: JEON JONG BAE , CHANG YOUNG WON
Published: March 2009

Microstructural evolution during compressive deformation of a meta-stable austenitic stainless steel has been investigated using an electron-backscattered diffraction (EBSD) technique. A local area tracking method has been adopted in order to observe the successive changes in local microstructures during the compression. The local microstructures could be observed in-situ from this method without using any in-situ stage, in addition to a precisely-controlled real time deformation process. Successive development of grain orientation spread, grain boundary misorientation and deformation-induced phase in the local areas of interest were successfully investigated from this method.
EVOLUTION OF STRAIN STATES AND TEXTURES IN AA 5052 SHEET DURING CROSS-ROLL ROLLING
Authors: KIM S.H. , KIM D.G. , KANG H.G. , HUH M.Y. , LEE J.S. , ENGLER O.
Published: March 2009

Cross-roll rolling of AA 5052 sheets was carried out using a rolling mill in which the roll axes are tilted by ±7.5° away from the transverse direction of the rolled sample. Besides cross-roll rolling, normal-rolling using a conventional rolling mill was also carried out with the same rolling schedule for clarifying the effect of cross-roll rolling. The evolution of strain states during cross-roll rolling was investigated by texture measurements and by three-dimensional finite element method (FEM) simulation. Cross-roll rolling gives rise to the operation of all three shear components ε12, ε13and ε23in the roll gap. This complex shear states during cross-roll rolling strongly reduce the intensities of the deformation texture components.
EXPERIMENTAL INVESTIGATION ON FRACTURE TOUGHNESS OF INTERFACE CRACK FOR ROCK/CONCRETE
Authors: YANG SHUICHENG , SONG LI , LI ZHE , HUANG SONGMEI
Published: March 2009

Fracture toughness is a critical input parameter for fracture-mechanics based fitness-for-service assessments, and it is preferable to determine this by experiment. In the present paper, fracture toughness of rock/concrete bimaterial interface was obtained by the tests which were performed on the universal material tester. A beam specimen with single-edge crack is used to form the different fracture mode mixity. The stress intensity factors of specimen per unit load with different combinations of K1 and K2 were calculated by the mixed hybrid finite element method on the principals of linear elastic interface fracture mechanics. By regressing the critical stress intensity factors of 7 specimen groups, two experiential fracture criterions of mixed crack interface were derived, and the fracture toughness([Formula: see text], [Formula: see text]) of rock/concrete were obtained further.
PREDICTION OF A MODIFIED PTW MODEL FOR VARIOUS TAYLOR IMPACT TESTS OF TANTALUM
Authors: KIM JONG-BONG , SHIN HYUNHO
Published: March 2009

The strain hardening part of the Preston-Tonks-Wallace (PTW) model, developed for the description of the plastic constitutive behavior of materials at wide ranges of strain, strain rate, and temperature, has been modified by employing the Voce equation. The prediction capability of the modified PTW (MPTW) has been investigated with reference to Taylor impact test results in the literature, and comparison has been made with the models of Johnson-Cook (JC), Steiberg-Guinan (SG), Zerilli-Armstrong (ZA), and PTW. Of the compared existing models, no model was appropriate for describing the results of various Taylor impact tests. However, the modified PTW is shown to predict fairly accurate results in terms of the length, diameter, and shape of the deformed specimen tested at different temperatures and impact velocity.
OPTICAL PROPERTIES OF CHEMICALLY PREPARED CdS QUANTUM DOTS IN POLYVINYL ALCOHOL
Authors: BARMAN J. , BORAH J. P. , SARMA K. C.
Published: March 2009

Excitonic effects are observed in the optical absorption and photoluminescence of strongly confined CdS quantum dots embedded in the polymer matrix. CdS nanoparticles of different crystallite sizes have been prepared by chemical route with polymer as a host material. The CdS nanocomposite film was made up of particle smaller than 5 nm and shows a composite band gap up to 3.2 eV, whereas the band gap for bulk hexagonal CdS is about 2.42 eV. Photoluminescence spectra show a strong emission band corresponding to electron–hole recombination and a weak band due to defect emission. The decrease of particle size was monitored from the U-V visible absorption measurement as well as photoluminescence, which suffered blue shift with decrease in particle size. The particle size and surface morphology were also analyzed by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM).
APPROXIMATE ANALYTICAL SOLUTIONS FOR THE RELATIVISTIC OSCILLATOR USING A LINEARIZED HARMONIC BALANCE METHOD
Authors: BELÉNDEZ A. , MÉNDEZ D. I. , ALVAREZ M. L. , PASCUAL C. , BELÉNDEZ T.
Published: March 2009

The analytical approximate technique developed by Wu et al. for conservative oscillators with odd nonlinearity is used to construct approximate frequency-amplitude relations and periodic solutions to the relativistic oscillator. By combining Newton's method with the method of harmonic balance, analytical approximations to the oscillation period and periodic solutions are constructed for this oscillator. The approximate periods obtained are valid for the complete range of oscillation amplitudes, A, and the discrepancy between the second approximate period and the exact one never exceeds 1.24%, and it tends to 1.09% when A tends to infinity. Excellent agreement of the approximate periods and periodic solutions with the exact ones are demonstrated and discussed.
STABILITY OF FLOW PAST TWO SIDE-BY-SIDE CIRCULAR CYLINDERS
Authors: LIU KUN , MA DONG-JUN , SUN DE-JUN , YIN XIE-YUAN
Published: March 2009

The global stability of flow past two side-by-side circular cylinders is investigated by a linear global stability analysis method based on a spectral/element Navier-Stokes solver. The special attention is paid to the parameter regime of 1<T/D<3, where T is the spacing between two cylinder centers and D the cylinder diameter. A remarkable feature we found is that there exist two critical Reynolds numbers associated with twice bifurcations, first a pitchfork and second a Hopf one, for about 1.55<T/D<1.65. A new flow pattern namely biased steady pattern is identified. In addition, the transition from in-phase lock-in to anti-phase lock-in pattern for larger separation distance T/D>1.65 is proved to be related to the switch between two leading eigenmodes.
A LATTICE BOLTZMANN METHOD-BASED FLUX SOLVER AND ITS APPLICATION TO SOLVE SHOCK TUBE PROBLEM
Authors: JI C. Z. , SHU C. , ZHAO N.
Published: March 2009

This paper presents an approach, which combines the conventional finite volume method (FVM) with the lattice Boltzmann Method (LBM), to simulate compressible flows. Similar to the Godunov scheme, in the present approach, LBM is used to evaluate the flux at the interface for local Riemann problem when solving Euler/Navier-Stokes (N-S) equations by FVM. Two kinds of popular compressible Lattice Boltzmann models are applied in the new scheme, and some numerical experiments are performed to validate the proposed approach. From the sharper shock profile and higher computational efficiency, numerical results demonstrate that the proposed scheme is superior to the conventional Godunov scheme. It is expected that the proposed scheme has a potential to become an efficient flux solver in solving compressible Euler/N-S equations.
FABRICATION AND PERFORMANCE OF HIGH TEMPERATURE STYLE FUNCTIONALLY GRADED PIEZOELECTRIC BENDING ACTUATORS
Authors: QIU J. H. , ZHU K. J. , JI H. L.
Published: March 2009

To avoid the delamination of bimorph actuator and enhance the performance of the room-temperature type functionally graded (RTFG) piezoelectric bending actuator, the high temperature type FG (HTFG) piezoelectric bending actuator was designed and fabricated. The material compositions with different dielectric and piezoelectric constants were selected from the Pb ( Ni 1/3 N b 2/3) O 3- PbZrO 3- PbTiO 3 (PNN-PZ-PT) family, and used as the five layers in the HTFG piezoelectric actuator. Compared with the FG actuator, the HTFG actuator has advantages for applications at high temperature. The durability of the fabricated HTFG piezoelectric actuators was measured in a vibration test and compared with that of the bimorph actuator to evaluate the improvement of performance. The results show that the durability of the HTFG piezoelectric actuators is much higher than that of the bimorph actuator.
NUMERICAL INVESTIGATION OF SUPERCOOLED DROPLETS IMPINGEMENT ON COMPLICATED ICING SURFACE
Authors: ZHANG DALIN , CHEN WEIJIAN
Published: March 2009

The supercooled droplet impingement on complicated icing surface has been investigated with the Eulerian method. A simplified air/droplet two-phase model is established, and an effective algorithm is proposed to deal with the dilute, weakly coupled air/droplet flows for aircraft icing problem. An Eulerian droplets computation code has been developed and validated with the iced NACA23012, and the results agree well with the experimental data. Meanwhile, compared with the results from the traditional Lagrangian method, it indicates that the Eulerian method gives a better prediction when the multiple impingement zones occur on complicated icing surface.
STUDY ON THE EFFECT OF VISCOSITY AND COMPRESSIBILITY ON ICE ACCRETION
Authors: ZHU CHENGXIANG , ZHU CHUNLING , FU BIN
Published: March 2009

Ice accretion on aircraft is studied by a numerical method. By solving governing equations, the flow field is obtained for analyzing the icing zone and calculating the ice quantity on different parts. Influence of the fluid viscosity and compressibility on icing characters is extensively studied. And it can be found that the results agree well with those calculated by LEWICE program. This achievement could be helpful to further research on ice accretion.
THE NUMERICAL SIMULATION OF FLOW AROUND EJECTION SYSTEM
Authors: ZHANG DALIN , WEI TAO
Published: March 2009

Aerodynamic characteristics of an Ejection Seat System at different angles of attack are studied by the numerical method and the flow mechanisms for such flows are carefully analyzed. The governing equations are Reynolds-averaged Navier-Stokes equations which are solved by the unstructured finite volume method. Upwind Osher scheme is used for spatial discretization and five-stage Runge-Kutta scheme is applied for temporal discretization. The DES model based on S-A one equation turbulence model is adopted. Parallel computation is based on the domain decomposition method and multi-block is achieved by using METIS system. The experimental data is used to validate this method. This research is helpful to understand the aerodynamic characteristics and flow mechanisms of Ejection Seat System at different angles of attack and Mach numbers, and can provide reasonable reference for Ejection Seat System design.
NUMERICAL SIMULATION FOR EFFECTS OF MICROCAPSULED PHASE CHANGE MATERIAL (MPCM) DISTRIBUTION ON HEAT AND MOISTURE TRANSFER IN POROUS TEXTILES
Authors: LI FENGZHI
Published: March 2009

In recent years, the use of phase change materials (PCM) to improve heat and moisture transfer properties of clothing has gained considerable attention. The PCM distribution in the clothing impacts heat and moisture transfer properties of the clothing significantly. For describing the mechanisms of heat and moisture transfer in clothing with PCM and investigating the effect of the PCM distribution, a new dynamic model of coupled heat and moisture transfer in porous textiles with PCM was developed. The effect of water content on physical parameters of textiles and heat transfer with phase change in the PCM microcapsules were considered in the model. Meanwhile, the numerical predictions were compared with experimental data, and good agreement was observed between the two, indicating that the model was satisfactory. Also the effects of the PCM distribution on heat transfer in the textiles-PCM microcapsule composites were investigated by using the model.
RESEARCH OF THE ROTATIONAL EFFECTS ON THE BOUNDARY LAYER OF WIND TURBINE BLADES
Authors: YANG RUI , LI REN-NIAN , HAN WEI , LI DE-SHUN
Published: March 2009

The flow field past the rotating blade of a horizontal axial wind turbine has been modeled with a full 3–D steady–RANS approach. Flow computations have been performed using the commercial finite–volume solver Fluent. The NREL phase VI wind turbine blade sections from the 3–D rotating geometry were chosen and the corresponding 2–D flow computations have been carried out for comparison with different angles of attack and in stalled conditions. The simulation results are analyzed. The main features of the boundary layer flow are described, for both the rotating blade and the corresponding 2–D profiles. Computed pressure distributions and aerodynamic coefficients show evidence of less lift losses after separation in the 3–D rotating case, mostly for the inward sections of the blade and the highest angles of attack, which is in agreement with the literature.
EFFECTS OF ROTATION SPEED ON THE GAS-SOLID-LIQUID THREE-PHASE FLOW IN MECHANICAL FLOTATION CELL
Authors: HAN WEI , LI RENNIAN , YANG RUI , LI QIFEI , SU FAZHNG
Published: March 2009

In order to analyze the effect of rotation speed of impeller on the inner flow and flotation dynamic characters of mechanical flotation, a kind of flotation is investigated. The gas-solid-liquid three-phase three-dimensional turbulent flow fields are analyzed numerically with the Mixture multi-phase model, K-ε turbulent model and Reynolds-Averaged Navier-Stokes equations. The void fraction test result of physical prototype is given with different rotation speeds. The simulation results show that the rotation speed of impeller has the important influence on the circle type of fluid, void fraction and speed distribution in the flotation with the same pressure of gas inlet. The experimental results show that the gas-solid-liquid three-phase flow fields with the design rotation speed is well with the flotation dynamic environment in the flotation, which also shows the importance of rotation speed of the impeller for the performance of the mechanical and pneumatic flotation.
Marketing Gentility: Boston's Businesswomen, 1780–1830
Authors: Carr Jacqueline Barbara
Published: March 2009

Drawing on a raft of data about women's business activities in Boston, 1780–1830, the article shows that widows and single women succeeded in a highly competitive marketplace by trading on their complex and diverse skills, business acumen, and personal connections and by strategically marketing gentility to an expanding middle-class.
Back to Basics
Authors: Gable Robert A. , Hester Peggy H. , Rock Marcia L. , Hughes Kimberly G.
Published: March 2009

Research begun in the 1960s provided the impetus for teacher educators to urge classroom teachers to establish classroom rules, deliver high rates of verbal/nonverbal praise, and, whenever possible, to ignore minor student provocations. In that there have been significant advances in the knowledge of what constitutes effective classroom management, a review of past-to-present literature was conducted to determine whether it is time to alter the thinking about one or more of these basic behavioral strategies. The research conducted over the years supports the basic tenets of these strategies, but with some important caveats. Finally, there are several newer strategies that warrant attention.
Differential stepwise evolution of SARS coronavirus functional proteins in different host species
Authors: Tang Xianchun , Li Gang , Vasilakis Nikos , Zhang Yuan , Shi Zhengli , Zhong Yang , Wang Lin-Fa , Zhang Shuyi
Published: March 2009

Background

SARS coronavirus (SARS-CoV) was identified as the etiological agent of SARS, and extensive investigations indicated that it originated from an animal source (probably bats) and was recently introduced into the human population via wildlife animals from wet markets in southern China. Previous studies revealed that the spike (S) protein of SARS had experienced adaptive evolution, but whether other functional proteins of SARS have undergone adaptive evolution is not known.

Results

We employed several methods to investigate selective pressure among different SARS-CoV groups representing different epidemic periods and hosts. Our results suggest that most functional proteins of SARS-CoV have experienced a stepwise adaptive evolutionary pathway. Similar to previous studies, the spike protein underwent strong positive selection in the early and middle phases, and became stabilized in the late phase. In addition, the replicase experienced positive selection only in human patients, whereas assembly proteins experienced positive selection mainly in the middle and late phases. No positive selection was found in any proteins of bat SARS-like-CoV. Furthermore, specific amino acid sites that may be the targets of positive selection in each group are identified.

Conclusion

This extensive evolutionary analysis revealed the stepwise evolution of different functional proteins of SARS-CoVs at different epidemic stages and different hosts. These results support the hypothesis that SARS-CoV originated from bats and that the spill over into civets and humans were more recent events.
The outcome of Cryptococcus neoformansintracellular pathogenesis in human monocytes
Authors: Alvarez Mauricio , Burn Tamika , Luo Yong , Pirofski Liise-anne , Casadevall Arturo
Published: March 2009

Background

Cryptococcus neoformansis an encapsulated yeast that is a facultative intracellular pathogen. The interaction between macrophages andC. neoformansis critical for extrapulmonary dissemination of this pathogenic yeast.C. neoformanscan either lyse macrophages or escape from within them through a process known as phagosomal extrusion. However, most studies of intracellular pathogenesis have been made with mouse cells and their relevance to human infection is uncertain. In this study we extended studies ofC. neoformans-macrophage cellular interaction/s to human peripheral blood monocytes.

Results

This study demonstrated thatC. neoformanscan shed polysaccharide within human monocytes, spread from cell to cell, and be extruded from them. Furthermore, human monocytes responded to ingestion ofC. neoformanswith cell cycle progression from G1 to S.

Conclusion

Similarities between mouse and human cells support the suitability of mouse cells for the study of intracellular pathogenesis mechanisms. Given that these hosts diverged over 70 million years ago, the similar pathogenic strategies forC. neoformansin murine and human cells supports the hypothesis that the mechanism that underlies the mammalian intracellular pathogenesis ofC. neoformansoriginated from interactions with a third host, possibly soil amoeboid predators, before the mammalian radiation.
Zinc transporter gene expression is regulated by pro-inflammatory cytokines: a potential role for zinc transporters in beta-cell apoptosis?
Authors: Egefjord Lærke , Jensen Jens Ledet , Bang-Berthelsen Claus Heiner , Petersen Andreas Brønden , Smidt Kamille , Schmitz Ole , Karlsen Allan Ertman , Pociot Flemming , Chimienti Fabrice , Rungby Jørgen , Magnusson Nils E
Published: March 2009

Background

β-cells are extremely rich in zinc and zinc homeostasis is regulated by zinc transporter proteins. β-cells are sensitive to cytokines, interleukin-1β (IL-1β) has been associated with β-cell dysfunction and -death in both type 1 and type 2 diabetes. This study explores the regulation of zinc transporters following cytokine exposure.

Methods

The effects of cytokines IL-1β, interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) on zinc transporter gene expression were measured in INS-1-cells and rat pancreatic islets. Being the more sensitive transporter, we further explored ZnT8 (Slc30A8): the effect of ZnT8 over expression on cytokine induced apoptosis was investigated as well as expression of the insulin gene and two apoptosis associated genes, BAX and BCL2.

Results

Our results showed a dynamic response of genes responsible for β-cell zinc homeostasis to cytokines: IL-1β down regulated a number of zinc-transporters, most strikingly ZnT8 in both islets and INS-1 cells. The effect was even more pronounced when mixing the cytokines. TNF-α had little effect on zinc transporter expression. IFN-γ down regulated a number of zinc transporters. Insulin expression was down regulated by all cytokines. ZnT8 over expressing cells were more sensitive to IL-1β induced apoptosis whereas no differences were observed with IFN-γ, TNF-α, or a mixture of cytokines.

Conclusion

The zinc transporting system in β-cells is influenced by the exposure to cytokines. Particularly ZnT8, which has been associated with the development of diabetes, seems to be cytokine sensitive.
Enhancing Interdisciplinary, Mathematics, and Physical Science in an Undergraduate Life Science Program through Physical Chemistry
Authors: Pursell David P.
Published: March 2009

BIO2010 advocates enhancing the interdisciplinary, mathematics, and physical science components of the undergraduate biology curriculum. The Department of Chemistry and Life Science at West Point responded by developing a required physical chemistry course tailored to the interests of life science majors. To overcome student resistance to physical chemistry, students were enabled as long-term stakeholders who would shape the syllabus by selecting life science topics of interest to them. The initial 2 yr of assessment indicates that students have a positive view of the course, feel they have succeeded in achieving course outcome goals, and that the course is relevant to their professional future. Instructor assessment of student outcome goal achievement via performance on exams and labs is comparable to that of students in traditional physical chemistry courses. Perhaps more noteworthy, both student and instructor assessment indicate positive trends from year 1 to year 2, presumably due to the student stakeholder effect.
Two-sided effect ofCordyceps sinensison dendritic cells in different physiological stages
Authors: Li Chia-Yang , Chiang Chi-Shiun , Tsai Min-Lung , Hseu Ruey-Shyang , Shu Wun-Yi , Chuang Chun-Yu , Sun Yuh-Chang , Chang Yuan-Shiun , Lin Jaung-Geng , Chen Chih-Sheng , Huang Ching-Lung , Hsu Ian C
Published: March 2009

Cordyceps sinensis (CS), a Chinese tonifying herb, has been widely used for centuries in Asian countries as a medicine and a health supplement. Although ample evidence indicates that CS can modulate immune responses, the functional effect of CS on dendritic cells (DCs) is still unclear. This study examines how CS affects human monocyte-derived DCs in two physiological states: naïve and LPS-induced inflammatory. Our experimental results demonstrate that CS acts as an activator and maturation inducer of immature DCs by stimulating the expression of costimulatory molecules and proinflammatory cytokines by DCs, enhancing the DC-induced, allogeneic T cell proliferation, and reducing the endocytic ability of DCs. In contrast, CS suppresses the LPS-induced, inflammatory response by decreasing the LPS-induced expression of costimulatory molecules and proinflammatory cytokines by DCs. CS also suppresses the LPS-induced, DC-elicited, allogeneic T cell proliferation and shifts the LPS-activated, DC-driven Th1 response toward a Th2 response. These results demonstrate that CS differentially regulates the DC activities according to the presence or absence of the inflammatory signs. Restated, with the lack of an ongoing inflammatory environment, CS primes DCs toward a Th1-type immunity, whereas in a potential inflammatory reaction, CS balances the over-reactivity of elicited Th1 immunity. This investigation illustrates the Yin-Yang balancing effects of CS as a medicine and a health supplement.
Lgl2 and E-cadherin act antagonistically to regulate hemidesmosome formation during epidermal development in zebrafish
Authors: Sonawane Mahendra , Martin-Maischein Hans , Schwarz Heinz , Nüsslein-Volhard Christiane
Published: March 2009

The integrity and homeostasis of the vertebrate epidermis depend on various cellular junctions. How these junctions are assembled during development and how their number is regulated remain largely unclear. Here, we address these issues by analysing the function of Lgl2, E-cadherin and atypical Protein kinase C (aPKC) in the formation of hemidesmosomes in the developing basal epidermis of zebrafish larvae. Previously, we have shown that a mutation in lgl2 (penner) prevents the formation of hemidesmosomes. Here we show that Lgl2 function is essential for mediating the targeting of Integrin alpha 6 (Itga6), a hemidesmosomal component, to the plasma membrane of basal epidermal cells. In addition, we show that whereas aPKCλ seems dispensable for the localisation of Itga6 during hemidesmosome formation,knockdown of E-cadherin function leads to an Lgl2-dependent increase in the localisation of Itga6. Thus, Lgl2 and E-cadherin act antagonistically to control the localisation of Itga6 during the formation of hemidesmosomes in the developing epidermis.
Complexant-assisted Fabrication of Football-like Nickel Architectures Covered by Hexagonal Nanoplatelets
Authors: Ni Xiaomin , Zheng Huagui , Cai Xin , Xiao Xiukun , Liao Guangxuan
Published: March 2009

Novel football-like nanostructures of metallic nickel with surfaces covered by hexagonal nanoplatelets were fabricated through a simple chemical reduction route with 2-hydroxy-4-(1-methylheptyloxy)benzophenone oxime in anti form (N530) as complexing agent. Formation of the unique nanostructures was reasonably ascribed to the special complex precursor and variation of the reaction rate at different stages. Magnetic properties of the nickel nanostructures were compared with other shaped counterparts.
Predicting preparatory behaviours for condom use in female undergraduate students: a one-year follow-up study
Authors: Gebhardt W A , van Empelen P , van Beurden D
Published: March 2009

Summary

The objective of this study is to investigate whether the Theory of Planned Behaviour (i.e. attitude, subjective norm, perceived behavioural control and intention), fluctuations in motivation over time, and variables from the Prototype-Willingness Model (i.e. behavioural expectation and behavioural willingness to have unprotected sex) predict preparatory behaviours for condom use. Sixty-two female undergraduates completed baseline and one-year follow-up questionnaires. Having condoms at home and carrying condoms were predicted by behavioural willingness to have unsafe sex at baseline. Having bought condoms was predicted by the behavioural expectation to use condoms with new partners at baseline. Intention and fluctuations in motivation did not emerge as significant predictors of preparatory actions. Female undergraduates, who are more willing to have unprotected sex under risk-conducive circumstances, are also less likely to prepare adequately for condom use, and thereby increase their chances of encountering such situations. Overall, the findings are in support of the Prototype-Willingness Model.
Identifying opportunities for sexually transmitted infection prevention: analysis of critical points in the care pathways of patients with gonorrhoea
Authors: Abu-Rajab K , Scoular A , Church S , Connell J , Winter A , Hart G
Published: March 2009

We applied the principles of Hazard Analysis and Critical Control Points (HACCP) to systematically analyse the care pathway of patients diagnosed with gonorrhoea to identify potential intervention opportunities for preventive action. Data were collected on individuals with culture-positive gonococcal infection during 27 February 2003 to 08 January 2004. Qualitative data were gathered within individual semi-structured interviews. Two hundred and twenty-three gonorrhoea patient episodes were evaluated. The median interval between presentation and treatment was significantly longer in females and men having sex with men (MSM), compared with heterosexual men ( P = 0.002). Females were significantly more likely to be in regular relationships at the timepoint of perceived infection acquisition than heterosexuals or MSM ( P < 0.0001). Four major themes emerged from the interviews: life-stage and infection risk, determinants of risk perception around sexual encounters, attitudes to preventing re-infection and condom use. These informed three potential ‘critical control points’: health-related attitudes/behaviours preceding infection; access to appropriate care and optimizing health promotion to prevent further infection.
A case study of delayed HIV-1 seroconversion highlights the need for Combo assays
Authors: Skidmore S , Devendra S , Weaver J , Short J , Osman H , Smit E
Published: March 2009

Summary

This report describes a case in which a patient took at least four months to seroconvert to anti-HIV positivity. A concomitant CMV infection probably contributed to the profound immune suppression observed. It is essential that fourth generation HIV antigen/antibody combo assays be used to ensure that such cases are not missed.
Non-tuberculous mycobacteria in the sputum of HIV-infected patients: infection or colonization?
Authors: Alvarez-Uria G , Falcó V , Martín-Casabona N , Crespo M , Villar del Saz S , Curran A , Ocaña I , Ribera E , Pahissa A
Published: March 2009

It can be difficult to establish the clinical significance of the isolation of non-tuberculous mycobacteria (NTM) from the sputum of HIV-infected patients. In this observational study, we have investigated factors associated with having NTM infection. During the period of the study, 10 patients had NTM infection and 14 had NTM colonization. Factors associated with having NTM infections were: CD4 lymphocyte count <50 cells/mL (odds ratio [OR] 10; 95% confidence interval [CI] 1.4–69.3), haemoglobin <11 g/dL (OR 7.2; 95% CI 1.08–47.9), weight loss (OR 9; 95% CI 1.3–63.9), duration of symptoms for more than a month (OR 54; 95% CI 4.2–692.5), the presence of acid fast bacilli (AFB) in sputum (OR 30.3; 95% CI 2.6–348.9) and repeated positive NTM cultures in other sputum samples (OR 4.3; 95% CI 1.6–11.7). In conclusion, we must suspect NTM infection in patients with long-standing symptoms, anaemia, low CD4 lymphocyte count, several positive sputum cultures and when AFB are seen.
Necrotizing fasciitis: a case of hip disarticulation in a postnatal intravenous drug abuser
Authors: Rajeswari J , Smith N A , Glass K , Howarth F
Published: March 2009

An interesting case of necrotizing fasciitis of the leg following emergency caesarian section in a known intravenous drug user. Postnatal day two she developed pain and swelling in the left leg. In view of her previous history, deep vein thrombosis (DVT) was the initial diagnosis. But, due to clinically worsening symptoms and no response to anticoagulation, further investigations were done which showed necrotizing fasciitis. Due to disease progression, a hip disarticulation was performed and the patient went on to full recovery.