bluuebunny/crossref_metadata_2025 huggingface dataset:
Melatonin reduces the expression of alpha‐synuclein in the dopamine containing neuronal regions of amphetamine‐treated postnatal rats
Authors: Sae‐Ung Kwankanit , Uéda Kenji , Govitrapong Piyarat , Phansuwan‐Pujito Pansiri
Published: July 2011

Abstract:  Alpha‐synuclein (α‐syn) is a neuronal protein that is involved in various degenerative disorders such as Parkinson’s disease. It is found in the presynaptic terminals and perinuclear zones of many brain regions. Amphetamine (AMPH), a psychostimulant drug abused progressively more commonly in recent years, has been known to induce neurotoxicity in the central dopaminergic pathway, which is associated with increased oxidative stress. Recently, AMPH has been shown to significantly increase the level of α‐syn in dopaminergic neuroblastoma cell cultures. Melatonin is recognized as an antioxidant for the nervous system. This study tested whether melatonin can attenuate the effect of AMPH on the expression of α‐syn in the dopaminergic pathway of the neonatal rat. Four‐day old postnatal rats (P4) were injected subcutaneously with either AMPH (increasing dose, 5–10 mg/kg daily) alone or AMPH with melatonin (2 mg/kg) daily at 10:00 AM for 7 consecutive days. As determined using Western blot, the level of α‐syn was significantly increased in the substantia nigra, dorsal striatum, nucleus accumbens, and prefrontal cortex of the AMPH‐treated group, while melatonin treatment either prior to AMPH or alone decreased the accumulation of the protein to 77%, 96%, 78%, and 77% of the control value, respectively. Furthermore, an immunofluorescent study showed that the α‐syn‐immunoreactivity increased noticeably in the nuclei of cell bodies and nerve terminals of the AMPH‐treated group. Again, melatonin lowered this immunoreactivity. These results indicate that melatonin has a direct or indirect effect in reducing the expression of α‐syn in the postnatal rat. The exact mechanism of this mitigation should be further investigated.
The prevalence of vitamin D deficiency and relationship with fracture risk in older women presenting in Australian general practice
Authors: Robinson Penelope J , Bell Robin J , Lanzafame Alfred , Kirby Catherine , Weekes Andrew , Piterman Leon , Davis Susan R
Published: July 2011

Aim:  To investigate vitamin D status among older women and to explore relationships between vitamin D and fracture risk and vertebral fractures.

Methods:  A total of 267 general practitioners recruited 2466 women aged >70 years with no known osteoporosis or fragility fracture. Serum 25‐hydroxy vitamin D (25(OH)D), bone mineral density by dual‐energy X‐ray absorptiometry (DXA) and vertebral fracture on thoracolumbar X‐ray were determined.

Results:  A total of 2368 women, median age 76 years, provided data and of these 13% were on vitamin D supplements. 25(OH)D levels were available for 907 (44.1%) of those not taking vitamin D. 88.3% of these had a level below 75 nmol/L. Serum 25(OH)D was negatively associated with age (P = 0.003) and body mass index (P < 0.001), and positively associated with lower latitude, femoral neck DXA T‐score (P = 0.044) and being Caucasian (P < 0.001).

Conclusions:  The vitamin D status of community‐dwelling older Australian women is inadequate, yet the use of supplements is low.
DbMDR: A Relational Database for Multidrug Resistance Genes as Potential Drug Targets
Authors: Gupta Sanchita , Mishra Manoj , Sen Naresh , Parihar Rashi , Dwivedi Gaurav Raj , Khan Feroz , Sharma Ashok
Published: July 2011

DbMDR is non‐redundant reference database of multidrug resistance (MDR) genes and their orthologs acting as potential drug targets. Drug resistance is a common phenomenon of pathogens, creating a serious problem of inactivation of drugs and antibiotics resulting in occurrence of diseases. Apart from other factors, the MDR genes present in pathogens are shown to be responsible for multidrug resistance. Much of the unorganized information on MDR genes is scattered across the literature and other web resources. Thus, consolidation of such knowledge about MDR genes into one database will make the drug discovery research more efficient. Mining of text for MDR genes has resulted into a large number of publications but in scattered and unorganized form. This information was compiled into a database, which enables a user not only to look at a particular MDR gene but also to find out putative homologs based on sequence similarity, conserved domains, and motifs in proteins encoded by MDR genes more efficiently. At present, DbMDR database contains 2843 MDR genes characterized experimentally as well as functionally annotated with cross‐referencing search support. The DbMDR database (http://203.190.147.116/dbmdr/) is a comprehensive resource for comparative study focused on MDR genes and metabolic pathway efflux pumps and intended to provide a platform for researchers for further research in drug resistance.
Synthesis and Anti‐Hypercholesterolemic Evaluations of Calcium Salts of 4‐Substituted Quinoline‐Based Mevalonic Acid
Authors: Hao Qun , Cai Zhengyan , Pan Jing , Li Yongjia , Xia Yuye , Min Yang , Sheng Yuchen , Zhou Weicheng
Published: July 2011

A series of calcium (3R,5S,6E)‐7‐[4,6,7,8‐substituted‐quinoline‐3‐yl]‐3,5‐dihydroxy‐hept‐6‐enoates was synthesized from the lactones, and the anti‐hypercholesterolemic evaluation in quails was presented in this report. It was found that most of the compounds significantly decreased levels of total cholesterol and low‐density lipoprotein. 2e showed better hypolipidemic effect than atorvastatin, and 2d and 2j exhibited comparable efficacy to atorvastatin. These three compounds were selected as the hypocholesterolemic candidates for further evaluation.
Cardiac Magnetic Resonance in the Differentiation of Neoplastic and Nonneoplastic Pericardial Effusion
Authors: Boddy K.N. , Sleeper M.M. , Sammarco C.D. , Weisse C. , Ghods S. , Litt H.I.
Published: July 2011

Background:Cardiac magnetic resonance (CMR) is the imaging modality of choice for cardiac tumors in people. Although neoplastic pericardial effusion (PE) carries a poor prognosis, benign idiopathic pericardial effusion does not. Definitive diagnosis is critical for surgical intervention, but currently available diagnostic techniques such as echocardiography and pericardial fluid cytology often are inconclusive.

Hypothesis/Objective:Describe CMR findings associated with PE and determine whether CMR aids in differentiation of benign and neoplastic causes of PE.

Animals:Eight client‐owned dogs with PE diagnosed by transthoracic echocardiography (TTE).

Methods:CMR was performed with a 1.5 T, including dark blood, steady‐state free procession cine, pre‐ and postcontrast T1‐weighted imaging, and delayed inversion recovery prepped imaging.

Results:CMR confirmed a cardiac mass and supported suspected tumor type in 4 dogs with suspected hemangiosarcoma. In 1 equivocal TTE case, CMR did not demonstrate a mass, but neoplasia was later diagnosed. In another equivocal case, CMR did not demonstrate a mass but showed findings consistent with a pericardiocentesis complication. In 1 dog without evidence of cardiac neoplasia, abdominal magnetic resonance imaging identified presumptive hepatic and splenic metastases. On reevaluation of the original CMR study, the 2 equivocal cases that were interpreted as tumor negative were reassessed as tumor positive.

Conclusions and Clinical Importance:CMR did not substantially improve diagnosis of cardiac tumors compared with TTE in these 8 cases, but it yielded useful descriptive information regarding extent, anatomic location, and potential tumor type and confirmed that CMR requires extensive additional training for tumor identification.
Influence of mechanical manipulations on the local inflammatory reaction in the equine colon
Authors: HOPSTER‐IVERSEN C. , HOPSTER K. , STASZYK C. , ROHN K. , FREEMAN D. , RÖTTING A. K.
Published: July 2011

Reasons for performing study:Large intestinal diseases in horses are characterised by inflammation, which could arise from the disease process with some contribution from intestinal manipulation. The effects of the latter are unknown but important to surgeons and could contribute to post operative complications.

Objectives:To characterise type and degree of intestinal inflammation induced by various mechanical stimuli in the equine ascending colon.

Methods:Laparotomy was performed in 12 horses, the left dorsal colon exteriorised and 3 segments randomly exposed to different mechanical manipulations: 1) enterotomy, 2) enterotomy and mucosal irritation and 3) serosal irritation. Intestinal biopsies were harvested before, immediately after and 30 min after each manipulation for histological evaluation. Eosinophils were detected with Luna's stain and neutrophils identified by immunohistochemical staining for calprotectin. Additionally, left dorsal colon samples from 14 horses from a jejunal ischaemia‐reperfusion study were collected immediately after laparotomy (7 horses) and at the end of the experiment without previous manipulation of the colon (7 horses). Horses were subjected to euthanasia at the end of both studies.

Results:Redistribution of mucosal neutrophils and eosinophils towards the luminal surface and increased neutrophilic infiltration of the submucosa were demonstrated after serosal and mucosal irritation. All manipulations resulted in serosal infiltration with neutrophils. Laparotomy and small intestinal manipulation increased mucosal eosinophilic infiltration.

Conclusions and potential relevance:Mechanical intestinal manipulation caused a rapid local inflammatory reaction in the mucosa, submucosa and serosa including a mucosal eosinophilic response. These changes could exacerbate existing inflammation in horses with large colon disease. Colic surgery can lead to intestinal inflammation in nonmanipulated intestine and this could contribute to a higher morbidity rate in horses after prolonged colic surgery. An intestinal biopsy should be collected at the beginning of surgery to avoid false interpretations.
Is there a statistical correlation between ultrasonographic findings and definitive diagnosis in horses with acute abdominal pain?
Authors: BECCATI F. , PEPE M. , GIALLETTI R. , CERCONE M. , BAZZICA C. , NANNARONE S.
Published: July 2011

Reason for performing study:Abdominal ultrasonography has become a part of the diagnostic investigation for the acute abdomen in many equine clinics. There is limited information on the correlation between abnormalities detected on abdominal ultrasonography and the specific category of small intestine (SI) and large intestine (LI) diseases.

Objectives:To investigate the relationship between abdominal ultrasonographic findings and disease categories that cause abdominal pain requiring surgery.

Methods:Medical records were reviewed for horses undergoing surgery orpost mortemexamination for colic. The ultrasound examination was performed to assess free peritoneal fluid, the left kidney, stomach, appearance and motility of the duodenum, identification, appearance, motility and thickness of small intestine loops, and the appearance and motility of the colon. Logistic regression analysis was used to identify associations between disease categories and ultrasonographic findings; a Chi‐squared test was used to test for associations between each variable and disease categories.

Results:The study included 158 horses. Distended and nonmotile SI loops were associated with strangulated obstruction (n = 45); increased free peritoneal fluid, completely distended SI loops with abnormal motility and thickened loops were associated with definitive diagnosis involving SI (n = 58). Failure to visualise the left kidney was associated with renosplenic entrapment (n = 16); thickened large colon (LC) was associated with LC strangulating volvulus (n = 9).

Conclusion:The use of abdominal ultrasonography can be used for the accurate definitive diagnosis involving SI and LI diseases.

Potential relevance:This retrospective study may be used as a basis for prospective studies to assess the ultrasonographic findings in horses with medical colic and to compare these with surgical findings.
(–)‐Epicatechin enhances fatigue resistance and oxidative capacity in mouse muscle
Authors: Nogueira Leonardo , Ramirez‐Sanchez Israel , Perkins Guy A. , Murphy Anne , Taub Pam R. , Ceballos Guillermo , Villarreal Francisco J. , Hogan Michael C. , Malek Moh H.
Published: July 2011

Non‐technical summary  During exercise, skeletal muscle performance depends in great part on the use of aerobic metabolism to supply the energetic demand of contractions. Endurance training increases the muscle aerobic capacity, which is not only associated with enhanced exercise performance, but also with a decreased risk of cardiovascular and metabolic diseases. Recently, it has been shown that regular use of small doses of dark chocolate may result in similar health benefits to exercise training. We show here that mice fed for 15 days with (–)‐epicatechin (present in dark chocolate) had improved exercise performance accompanied by: (1) an increased number of capillaries in the hindlimb muscle; and (2) an increased amount of muscle mitochondria as well as signalling for mitochondrial biogenesis. These results suggest that (–)‐epicatechin increases the capacity for muscle aerobic metabolism, thereby delaying the onset of fatigue. These findings may have potential application for clinical populations experiencing muscle fatigue.
Simulation of Trailing Edge Vortex Shedding in a Transonic Turbine Cascade
Authors: Currie T. C. , Carscallen W. E.
Published: July 2011

Midspan losses in the NRC transonic turbine cascade peak at an exit Mach number (M2) of ~1.0 and then decrease by ~40 percent as M2 is increased to the design value of 1.16. Since recent experimental results suggest that the decrease may be related to a reduction in the intensity of trailing edge vortex shedding, both steady and unsteady quasi-three-dimensional Navier–Stokes simulations have been performed with a highly refined (unstructured) grid to determine the role of shedding. Predicted shedding frequencies are in good agreement with experiment, indicating the blade boundary layers and trailing edge separated free shear layers have been modeled satisfactorily, but the agreement for base pressures is relatively poor, probably due largely to false entropy created downstream of the trailing edge by numerical dissipation. The results nonetheless emphasize the importance of accounting for the effect of vortex shedding on base pressure and loss.
Validation of a Nonlinear Unsteady Aerodynamic Simulator for Vibrating Blade Rows
Authors: Ayer T. C. , Verdon J. M.
Published: July 2011

A time-accurate Euler/Navier–Stokes analysis is applied to predict unsteady subsonic and transonic flows through a vibrating cascade. The intent is to validate this nonlinear analysis along with an existing linearized inviscid analysis via result comparisons for unsteady flows that are representative of those associated with blade flutter. The time-accurate analysis has also been applied to determine the relative importance of nonlinear and viscous effects on blade response. The subsonic results reveal a close agreement between inviscid and viscous unsteady blade loadings. Also, the unsteady surface pressure responses are essentially linear, and predicted quite accurately using a linearized inviscid analysis. For unsteady transonic flows, shocks and their motions cause significant nonlinear contributions to the local unsteady response. Viscous displacement effects tend to diminish shock strength and impulsive unsteady shock loads. For both subsonic and transonic flows, the energy transfer between the fluid and the structure is essentially captured by the first-harmonic component of the nonlinear unsteady solutions, but in transonic flows, the nonlinear first-harmonic and the linearized inviscid responses differ significantly in the vicinity of shocks.
Calculation of Tip Clearance Effects in a Transonic Compressor Rotor
Authors: Chima R. V.
Published: July 2011

The flow through the tip clearance region of a transonic compressor rotor (NASA rotor 37) was computed and compared to aerodynamic probe and laser anemometer data. Tip clearance effects were modeled both by gridding the clearance gap and by using a simple periodicity model across the ungridded gap. The simple model was run with both the full gap height, and with half the gap height to simulate a vena-contracta effect. Comparisons between computed and measured performance maps and downstream profiles were used to validate the models and to assess the effects of gap height on the simple clearance model. Recommendations were made concerning the use of the simple clearance model. Detailed comparisons were made between the gridded clearance gap solution and the laser anemometer data near the tip at two operating points. The computed results agreed fairly well with the data but overpredicted the extent of the casing separation and underpredicted the wake decay rate. The computations were then used to describe the interaction of the tip vortex, the passage shock, and the casing boundary layer.
IGV–Rotor Interaction Analysis in a Transonic Compressor Using the Navier–Stokes Equations
Authors: Arnone A. , Pacciani R.
Published: July 2011

A recently developed, time-accurate multigrid viscous solver has been extended to handle quasi-three-dimensional effects and applied to the first stage of a modern transonic compressor. Interest is focused on the inlet guide vane (IGV)-rotor interaction where strong sources of unsteadiness are to be expected. Several calculations have been performed to predict the stage operating characteristics. Flow structures at various mass flow rates, from choke to near stall, are presented and discussed. Comparisons between unsteady and steady pitch-averaged results are also included in order to obtain indications about the capabilities of steady, multi-row analyses.
Laser-Doppler-Velocimetry Measurements in a Cascade of Compressor Blades at Stall
Authors: Hobson G. V. , Williams A. J. H. , Ganaim Rickel H. J.
Published: July 2011

Compressor stall was simulated in the Low-Speed Cascade Wind Tunnel at the Turbopropulsion Laboratory of the Naval Postgraduate School. The test blades were of controlled-diffusion design with a solidity of 1.67, and stalling occurred at 10 deg of incidence above the design inlet air angle. All measurements were taken at a flow Reynolds number, based on chord length, of 700,000. Laser-sheet flow visualization techniques showed that the stalling process was unsteady and occurred over the whole cascade. Detailed laser-Doppler-velocimetry measurements over the suction side of the blades showed regions of continuous and intermittent reverse flow. The measurements of the continuous reverse flow region at the leading edge were the first data of their kind in the leading edge separation bubble. The regions of intermittent reverse flow, measured with laser-Doppler velocimeter, corresponded to the flow visualization studies. Blade surface pressure measurements showed a decrease in normal force on the blade, as would be expected at stall. Data are presented in a form that characterizes the unsteady positive and negative velocities about their mean, for both the continuous reverse flow regions and the intermittent reverse flow regions.
Vortex Shedding From Struts in an Annular Exhaust Diffuser
Authors: Fric T. F. , Villarreal R. , Auer R. O. , James M. L. , Ozgur D. , Staley T. K.
Published: July 2011

Results from scale-model experiments and industrial gas turbine tests show that strut vortex shedding in an annular exhaust diffuser can effectively be modified by adding tapered chord to the struts. The struts are bluff bodies at full-speed, no-load conditions, when inlet swirl is close to 60 deg. Data from wind tunnel tests show that wake Strouhal number is 0.47, larger than that expected for an isolated cylinder wake. This value of Strouhal number agrees with those measured in full-scale exhaust diffusers. Wind tunnel tests showed that a strut with tapered chord most effectively reduced wake amplitudes and shifted shedding frequency. The tapered strut was also effective in reducing shedding amplitude in a scale-model diffuser. Finally, gas turbine tests employing a tapered strut showed significant reductions in unsteady pressure and noise. A major benefit of strut taper is a reduction of noise by uncoupling of vortex shedding from acoustic resonant response.
An Experimental Study of Turbine Vane Heat Transfer With Water–Air Cooling
Authors: Nirmalan N. V. , Weaver J. A. , Hylton L. D.
Published: July 2011

This paper presents data showing the improvement in cooling effectiveness of turbine vanes through the application of water–air cooling technology in an industrial/utility engine application. The technique utilizes a finely dispersed water-in-air mixture that impinges on the internal surfaces of turbine airfoils to produce very high cooling rates. An airfoil was designed to contain a standard impingement tube, which distributes the water–air mixture over the inner surface of the airfoil. The water flash vaporizes off the airfoil inner wall. The resulting mixture of air–steam–water droplets is then routed through a pin fin array in the trailing edge region of the airfoil where additional water is vaporized. The mixture then exits the airfoil into the gas path through trailing edge slots. Experimental measurements were made in a three-vane, linear, two-dimensional cascade. The principal independent parameters—Mach number, Reynolds number, wall-to-gas temperature ratio, and coolant-to-gas mass flow ratio—were maintained over ranges consistent with typical engine conditions. Five impingement tubes were utilized to study geometry scaling, impingement tube-to-airfoil wall gap spacing, impingement tube hole diameter, and impingement tube hole patterns. The test matrix was structured to provide an assessment of the independent influence of parameters of interest, namely, exit Mach number, exit Reynolds number, gas-to-coolant temperature ratio, water-and air-coolant-to-gas mass flow ratios, and impingement tube geometry. Heat transfer effectiveness data obtained in this program demonstrated that overall cooling levels typical for air-cooled Vanes could be achieved with the water–air cooling technique with reductions of cooling air flow of significantly more than 50 percent.
Heat Transfer Measurements to a Gas Turbine Cooling Passage With Inclined Ribs
Authors: Wang Z. , Ireland P. T. , Kohler S. T. , Chew J. W.
Published: July 2011

The local heat transfer coefficient distribution over all four walls of a large-scale model of a gas turbine cooling passage have been measured in great detail. A new method of determine the heat transfer coefficient to the rib surface has been developed and the contribution of the rib, at 5 percent blockage, to the overall roughened heat transfer coefficient was found to be considerable. The vortex-dominated flow field was interpreted from the detailed form of the measured local heat transfer contours. Computational Fluid Dynamics calculations support this model of the flow and yield friction factors that agree with measured values. Advances in the heat transfer measuring technique and data analysis procedure that confirm the accuracy of the transient method are described in full.
Design and Testing of Multistage Centrifugal Compressors With Small Diffusion Ratios
Authors: Aalburg C. , Simpson A. , Schmitz M. B. , Michelassi V. , Evangelisti S. , Belardini E. , Ballarini V.
Published: July 2011

Two stators of a multistage centrifugal compressor with progressively smaller outer radii have been designed, built, and tested. The aim was to achieve a significant reduction in the outer diameter of the compressor stage without compromising performance. The reduction in size was achieved by reducing the diffusion ratio (outer radius/inner radius) of the vaneless diffuser in two steps. In the first step, the outer diameter of the entire stage was reduced by 8% compared with the baseline design. In the second stage, the outer diameter was reduced by 14%. The outer radius of the smallest design was limited by the impeller exit diameter, which was kept constant, as was the axial length of the stage. The large radius baseline design has been tested on a rotating rig in a 1.5 stage setup. This setup aimed at simulating the multistage behavior by applying a pseudostage upstream of the main stage. The pseudostage consisted of a set of nonrotating preswirl vanes in order to mimic an upstream impeller and was followed by a scaled version of the return channel of the main stage. The experimental database was then used to calibrate a 1D analysis code and 3D–computational fluid dynamics methods for the ensuing design and optimization part. By applying an extensive design-of-experiments, the endwalls as well as the vanes of the stator part were optimized for maximum efficiency and operation range. In order to preserve the multistage performance, the optimization was constrained by keeping the circumferentially averaged spanwise flow profiles at the exit of the smaller radius stages within close limits to the original design. The reduced radius designs were then tested in the same 1.5 stage setup as the baseline design. The results indicate that the reduction in size was feasible without compromising the efficiency and operation range of the stage.
Spectral Element Approach to Wave Propagation in Uncertain Composite Beam Structures
Authors: Ajith V. , Gopalakrishnan S.
Published: July 2011

This paper presents a study of the wave propagation responses in composite structures in an uncertain environment. Here, the main aim of the work is to quantify the effect of uncertainty in the wave propagation responses at high frequencies. The material properties are considered uncertain and the analysis is performed using Neumann expansion blended with Monte Carlo simulation under the environment of spectral finite element method. The material randomness is included in the conventional wave propagation analysis by different distributions (namely, the normal and the Weibul distribution) and their effect on wave propagation in a composite beam is analyzed. The numerical results presented investigates the effect of material uncertainties on different parameters, namely, wavenumber and group speed, which are relevant in the wave propagation analysis. The effect of the parameters, such as fiber orientation, lay-up sequence, number of layers, and the layer thickness on the uncertain responses due to dynamic impulse load, is thoroughly analyzed. Significant changes are observed in the high frequency responses with the variation in the above parameters, even for a small coefficient of variation. High frequency impact loads are applied and a number of interesting results are presented, which brings out the true effects of uncertainty in the high frequency responses.
Transient Thermomechanical Contact of an Impacting Sphere on a Moving Flat
Authors: Ovcharenko A. , Yang M. , Chun K. , Talke F. E.
Published: July 2011

Contact between a slider and a magnetic recording disk is modeled as transient contact of a sphere on a moving flat. The sphere is assumed to be rigid, and the flat is treated as an elastic-plastic body with isotropic hardening. Heat generation is related to friction at the contact interface. Dimensionless solutions are obtained for maximum temperature rise, maximum contact force, maximum contact area, and maximum penetration as a function of dimensionless vertical initial velocity of the sphere. It is observed that transient thermomechanical contact with elastic-plastic deformation deviates from “classical theories” for dynamic elastic and quasi-static elastic-plastic contacts as the dimensionless vertical initial velocity of the sphere increases. The results are applied to optimize the slider-disk interface in a hard disk drive with respect to slider-disk contacts.
Face-Down Solid Particle Receiver Using Recirculation
Authors: Röger Marc , Amsbeck Lars , Gobereit Birgit , Buck Reiner
Published: July 2011

Solar thermal energy generation needs receiver technologies which can drive highly efficient turbines and decouple the collection of energy from its use by an economic storage technology. High-temperature solid particle receivers for solar tower systems with particle storage are one option. Important issues regarding high-temperature particle receivers are minimization of convective losses, no particle loss due to susceptibility to wind, and high efficiency also in part-load operation. A design approach facing these challenges is the face-down receiver using recirculation of particles. A screening performance analysis studying different recirculation patterns is presented. Using smart recirculation schemes, high receiver efficiencies can be maintained also at part-load operation (100% load ∼90%; 50% load ∼86%; 20% load ∼67%). Simulations of the face-down geometry yield total annual solar-to-electric efficiencies of 24% using a surround field. From the analyses, it can be concluded that solid particle receivers using smart recirculation patterns are a viable receiver option for storage and high-temperature high-efficiency turbine processes.
A Model of Contact With Adhesion of a Layered Elastic-Plastic Microsphere With a Rigid Flat Surface
Authors: Eid H. , Joshi N. , McGruer N. E. , Adams G. G.
Published: July 2011

A finite element model of a layered hemisphere contacting a rigid flat, which includes the effect of adhesion, is developed. In this analysis elastic-plastic material properties were used for each of the materials comprising the layered hemisphere. The inclusion of the effect of adhesion, which was accomplished with the Lennard-Jones potential, required a special procedure. This configuration is of general theoretical interest in the understanding of adhesion. It has also been suggested as a possible design for a microswitch contact because, with an appropriate choice of metals, it has the potential to achieve low adhesion, low contact resistance, and high durability. The effect of the layer thickness on the adhesive contact was investigated. In particular the influences of layer thickness on the pull-off force, maximum contact radius, and contact resistance were determined. The results are presented as load versus interference and contact radius versus interference for loading and unloading from different values of the maximum interference.
Proteome-Wide Mapping of the
Drosophila
Acetylome Demonstrates a High Degree of Conservation of Lysine Acetylation
Authors: Weinert Brian T. , Wagner Sebastian A. , Horn Heiko , Henriksen Peter , Liu Wenshe R. , Olsen Jesper V. , Jensen Lars J. , Choudhary Chunaram
Published: July 2011

Comparing the acetylomes with the phosphoproteomes of flies and humans suggests that phosphorylation sites may have evolved faster than did acetylation sites.
Active “Par”-titioning of Bacterial Chemotaxis Proteins
Authors: Thompson Heather M.
Published: July 2011

Bacterial ParA-like ATPases mediate cell cycle–dependent localization of chemotaxis proteins to cell poles.
Use It, Then Lose It
Authors: Hurtley Stella M.
Published: July 2011

A bacterial pathogen reverses the modification of a host cell protein involved in membrane trafficking.
Concentrations of Tenofovir and Emtricitabine in Saliva: Implications for Preexposure Prophylaxis of Oral HIV Acquisition
Authors: de Lastours Victoire , Fonsart Julien , Burlacu Ruxandra , Gourmel Bernard , Molina Jean-Michel
Published: July 2011

To prevent acquisition of HIV through oral sex, drugs used for preexposure prophylaxis (Prep) need to diffuse in saliva. We measured tenofovir (TFV) and emtricitabine (FTC) concentrations simultaneously in the plasma and saliva of 41 HIV-infected patients under stable antiretroviral treatment. Mean ratios of saliva/plasma concentration were 3% (±4%) and 86.9% (±124%) for TFV and FTC, respectively. Tenofovir disoproxil fumarate (TDF) should be used in combination with FTC to prevent oral acquisition of HIV.
Pneumolysin with Low Hemolytic Activity Confers an Early Growth Advantage to Streptococcus pneumoniae in the Blood
Authors: Harvey Richard M. , Ogunniyi Abiodun D. , Chen Austen Y. , Paton James C.
Published: July 2011

Streptococcus pneumoniae
is a leading cause of human diseases such as pneumonia, bacteremia, meningitis, and otitis media. Pneumolysin (Ply) is an important virulence factor of
S. pneumoniae
and a promising future vaccine target. However, the expansion of clones carrying
ply
alleles with reduced hemolytic activity has been observed in serotypes associated with outbreaks of invasive disease and includes an allele identified in a highly virulent serotype 1 isolate (
ply
4496). The virulence of Ply-deficient and
ply
allelic-replacement derivatives of
S. pneumoniae
D39 was compared with that of wild-type D39. In addition, the protective immunogenicity of Ply against pneumococci with low versus high hemolytic activity was also investigated. Replacement of D39
ply
with
ply
4496 resulted in a small but statistically significant reduction of virulence. However, both native Ply- and Ply4496-expressing strains were significantly more virulent than a Ply-deficient mutant. While the numbers of both Ply- and Ply4496-expressing isolate cells were higher in the blood than the numbers of Ply-deficient mutant cells, the growth of the Ply4496-expressing strain was superior to that of the wild type in the first 15 h postchallenge. Ply immunization provided protection regardless of the hemolytic activity of the challenge strain. In summary, we show that low-hemolytic-activity Ply alleles contribute to systemic virulence and may provide a survival advantage in the blood. Moreover, pneumococci expressing such alleles remain vulnerable to Ply-based vaccines.
Soil-water characteristic curve and permeability function for unsaturated cracked soil
Authors: Li J.H. , Zhang L.M. , Li X.
Published: July 2011

Cracks are widely present in natural and engineered soils. As water infiltration into a cracked soil often starts from unsaturated conditions, the soil-water characteristic curve (SWCC) and permeability function for the cracked soil are required when conducting seepage analysis. This paper presents a method to predict the SWCC and permeability function for cracked soil considering crack volume changes during drying–wetting processes. The cracked soil is viewed as an overlapping continuum of a crack network system and a soil matrix system. The pore-size distributions for the two pore systems at a particular state can be determined and used to estimate the SWCCs and permeability functions. The estimated SWCCs and permeability functions for the two pore systems can be combined to give the SWCC and the permeability function for the cracked soil at that state. Then, the SWCC and permeability function for the cracked soil at different states along a crack development path can be obtained and combined to give the SWCC or permeability function for the cracked soil considering crack volume changes. Examples are presented to illustrate the prediction of the SWCCs and permeability functions for a cracked soil along five crack development paths.
Comparison of fixed and focal point seed transfer systems for reforestation and assisted migration: a case study for interior spruce in British Columbia
Authors: Ukrainetz Nicholas K. , O’Neill Gregory A. , Jaquish Barry
Published: July 2011

In forestry, science-based seed transfer systems, the foundation of effective reforestation programs, will likely be used in some form to mitigate the negative effects of climate change. In this study, we developed fixed and focal point seed transfer systems for interior spruce ( Picea glauca (Moench) Voss, Picea engelmannii Parry ex Engelm., and their hybrids) in British Columbia, Canada, and compared the effectiveness of both systems. Growth, phenology, and physiology traits were measured for 112 populations, and population means were transformed to principal components that were modeled using climate variables and multiple regression analysis. Compared with the fixed seed zone system, the focal point system had a greater area of seed use for a given risk of maladaptation. The relationship between growth and adaptive distance (i.e., adaptive similarity between test populations and populations local to test sites) was used to calculate critical seed transfer distances for focal point seed zones, which were defined according to expected forfeiture of growth. Changes in climate observed over the past 100 years and predicted in the next one third of a rotation were used to calculate appropriate assisted migration distances and develop methods for incorporating assisted migration into a focal point seed transfer system.
Human recombinant erythropoietin alters the flow-dependent vasodilatation of in vitro perfused rat mesenteric arteries with unbalanced endothelial endothelin-1 / nitric oxide ratio
Authors: Barhoumi Tlili , Jallat Isabelle , Berthelot Alain , Laurant Pascal
Published: July 2011

Chronic use of human recombinant erythropoietin (r-HuEPO) is accompanied by serious vascular side effects related to the rise in blood viscosity and shear stress. We investigated the direct effects of r-HuEPO on endothelium and nitric oxide (NO)-dependent vasodilatation induced by shear stress of cannulated and pressurized rat mesenteric resistance arteries. Intravascular flow was increased in the presence or absence of the NO synthase inhibitor NG-nitro-l-arginine methyl ester (L-NAME; 10−4mol/L). In the presence of r-HuEPO, the flow-dependent vasodilatation was attenuated, while L-NAME completely inhibited it. The association of r-HuEPO and L-NAME caused a vasoconstriction in response to the rise in intravascular flow. Bosentan (10−5mol/L), an inhibitor of endothelin-1 (ET-1) receptors, corrected the attenuated vasodilatation observed with r-HuEPO and inhibited the vasoconstriction induced by flow in the presence of r-HuEPO and L-NAME. r-HuEPO and L-NAME exacerbated ET-1 vasoconstriction. At shear stress values of 2 and 14 dyn/cm2(1 dyn = 10–5N), cultured EA.hy926 endothelial cells incubated with r-HuEPO, L-NAME, or both released greater ET-1 than untreated cells. In conclusion, r-HuEPO diminishes flow-induced vasodilatation. This inhibitory effect seems to implicate ET-1 release. NO withdrawal exacerbates the vascular effects of ET-1 in the presence of r-HuEPO. These findings support the importance of a balanced endothelial ET-1:NO ratio to avoid the vasopressor effects of r-HuEPO.
MONOPOLES IN THE PLAQUETTE FORMULATION OF THE 3D SU(2) LATTICE GAUGE THEORY
Authors: BORISENKO O. , VOLOSHYN S. , BOHÁČIK J.
Published: July 2011

Using a plaquette formulation for lattice gauge models we describe monopoles of the three-dimensional SU(2) theory which appear as configurations in the complete axial gauge and violate the continuum Bianchi identity. Furthermore, we derive a dual formulation for the Wilson loop in arbitrary representation and calculate the form of the interaction between generated electric flux and monopoles in the region of a weak coupling relevant for the continuum limit. The effective theory which controls the interaction is of the sine-Gordon type model. The string tension is calculated within the semiclassical approximation.
HIGHER-ORDER SUSY, EXACTLY SOLVABLE POTENTIALS, AND EXCEPTIONAL ORTHOGONAL POLYNOMIALS
Authors: QUESNE C.
Published: July 2011

Exactly solvable rationally-extended radial oscillator potentials, whose wave functions can be expressed in terms of Laguerre-type exceptional orthogonal polynomials, are constructed in the framework of kth-order supersymmetric quantum mechanics, with special emphasis on k = 2. It is shown that for μ = 1, 2, and 3, there exist exactly μ distinct potentials of μth type and associated families of exceptional orthogonal polynomials, where μ denotes the degree of the polynomial gμ arising in the denominator of the potentials.
EARLY USABILITY MEASUREMENT IN MODEL-DRIVEN DEVELOPMENT: DEFINITION AND EMPIRICAL EVALUATION
Authors: PANACH JOSE IGNACIO , CONDORI-FERNÁNDEZ NELLY , VOS TANJA , AQUINO NATHALIE , VALVERDE FRANCISCO
Published: July 2011

Usability is currently a key feature for developing quality systems. A system that satisfies all the functional requirements can be strongly rejected by end-users if it presents usability problems. End-users demand intuitive interfaces and an easy interaction in order to simplify their work. The first step in developing usable systems is to determine whether a system is or is not usable. To do this, there are several proposals for measuring the system usability. Most of these proposals are focused on the final system and require a large amount of resources to perform the evaluation (end-users, video cameras, questionnaires, etc.). Usability problems that are detected once the system has been developed involve a lot of reworking by the analyst since these changes can affect the analysis, design, and implementation phases. This paper proposes a method to minimize the resources needed for the evaluation and reworking of usability problems. We propose an early usability evaluation that is based on conceptual models. The analyst can measure the usability of attributes that depend on conceptual primitives. This evaluation can be automated taking as input the conceptual models that represent the system abstractly.
AN EXPLORATION OF FUNCTIONAL SIZE BASED EFFORT ESTIMATION MODELS
Authors: TUNALILAR SECKIN , DEMIRORS ONUR
Published: July 2011

A number of methods have been proposed to build a relationship between effort and size. These models are generally based on regression analysis and a widely accepted model is not yet available. Although in some sizing methods, such as MKII and IFPUG, different multipliers for the base functional components (BFC) exist, their origin and the purpose of their usage are undefined. The COSMIC method does not treat components separately and assigns the same measurement unit to each of them. In this study we used the Artificial Neural Network and regression based methods to create effort estimation models that take the four components of the COSMIC method into consideration. In the research we compared several functional size based effort models in terms of accuracy using a reliable company dataset. These models comprised not only the generic models proposed in the literature or currently in use, but also specific models that we generated using our dataset with a single and multi-variate regression analysis and the ANN method. We also explored the effect of functional similarity (FS) using our specific models. We found that using BFC instead of total size improved effort estimation models and the ANN method is a useful approach to calibrate these components according to the company characteristics.
MEASURING SOFTWARE FUNCTIONAL SIZE FROM BUSINESS PROCESS MODELS
Authors: MONSALVE CARLOS , ABRAN ALAIN , APRIL ALAIN
Published: July 2011

ISO 14143-1 specifies that a functional size measurement (FSM) method must provide measurement procedures to quantify the functional user requirements (FURs) of software. Such quantitative information, functional size, is typically used, for instance, in software estimation. One of the international standards for FSM is the COSMIC FSM method — ISO 19761 — which was designed to be applied both to the business application (BA) software domain and to the real-time software domain. A recurrent problem in FSM is the availability and quality of the inputs required for measurement purposes; that is, well documented FURs. Business process (BP) models, as they are commonly used to gather requirements from the early stages of a project, could be a valuable source of information for FSM. In a previous article, the feasibility of such an approach for the BA domain was analyzed using the Qualigram BP modeling notation. This paper complements that work by: (1) analyzing the use of BPMN for FSM in the BA domain; (2) presenting notation-independent guidelines for the BA domain; and (3) analyzing the possibility of using BP models to perform FSM in the real-time domain. The measurement results obtained from BP models are compared with those of previous FSM case studies.
FAST ALGORITHMIC NIELSEN–THURSTON CLASSIFICATION OF FOUR-STRAND BRAIDS
Authors: CALVEZ MATTHIEU , WIEST BERT
Published: July 2011

We give an algorithm which decides the Nielsen–Thurston type of a given four-strand braid. The complexity of our algorithm is quadratic with respect to word length. The proof of its validity is based on a result which states that for a reducible 4-braid which is as short as possible within its conjugacy class (short in the sense of Garside), reducing curves surrounding three punctures must be round or almost round. As an application, we give a polynomial time solution to the conjugacy problem for non-pseudo-Anosov four-strand braids.
SINGULAR PERTURBATION ANALYSIS ON A HOMOGENEOUS OCEAN CIRCULATION MODEL
Authors: JUNG CHANG-YEOL , PETCU MADALINA , TEMAM ROGER
Published: July 2011

In this article, we consider the barotropic quasigeostrophic equation of the ocean in the context of the β-plane approximation and small viscosity (see, e.g., [21, 22]). The aim is to study the behavior of the solutions when the viscosity goes to zero. To avoid the substantial complications due to the corners (see, e.g., [25]) which will be addressed elsewhere, we assume periodicity in one direction (0y). The behavior of the solution in the boundary layers at x = 0, 1 necessitate the introduction of several correctors, solving various analogues of the Prandtl equation. Convergence is obtained at all orders even in the nonlinear case. We also establish as an auxiliary result, the [Formula: see text] regularity of the solutions of the viscous and inviscid quasigeotrophic equations.
Transcriptional analysis of the endothelial response to diabetes reveals a role for galectin-3
Authors: Darrow April L. , Shohet Ralph V. , Maresh J. Gregory
Published: July 2011

To characterize the endothelial dysfunction associated with Type II diabetes, we surveyed transcriptional responses in the vascular endothelia of mice receiving a diabetogenic, high-fat diet. Tie2-GFP mice were fed a diet containing 60% fat calories (HFD); controls were littermates fed normal chow. Following 4, 6, and 8 wk, aortic and leg muscle tissues were enzymatically dispersed, and endothelial cells were obtained by fluorescence-activated cell sorting. Relative mRNA abundance in HFD vs. control endothelia was measured with long-oligo microarrays; highly dysregulated genes were confirmed by real-time PCR and protein quantification. HFD mice were hyperglycemic by 2 wk and displayed vascular insulin resistance and decreased glucose tolerance by 5 and 6 wk, respectively. Endothelial transcripts upregulated by HFD included galectin-3 ( Lgals3), 5-lipoxygenase-activating protein, and chemokine ligands 8 and 9. Increased LGALS3 protein was detected in muscle endothelium by immunohistology accompanied by elevated LGALS3 in the serum of HFD mice. Our comprehensive analysis of the endothelial transcriptional response in a model of Type II diabetes reveals novel regulation of transcripts with roles in inflammation, insulin sensitivity, oxidative stress, and atherosclerosis. Increased endothelial expression and elevated humoral levels of LGALS3 supports a role for this molecule in the vascular response to diabetes, and its potential as a direct biomarker for the inflammatory state in diabetes.
Integral Inequalities on Time Scales via the Theory of Isotonic Linear Functionals
Authors: Anwar Matloob , Bibi Rabia , Bohner Martin , Pečarić Josip
Published: July 2011

We apply the theory of isotonic linear functionals to derive a series of known inequalities, extensions of known inequalities, and new inequalities in the theory of dynamic equations on time scales.