bluuebunny/crossref_metadata_2025 huggingface dataset:
Presence of Putative Repeat-in-Toxin Gene
tosA
in Escherichia coli Predicts Successful Colonization of the Urinary Tract
Authors: Vigil Patrick D. , Stapleton Ann E. , Johnson James R. , Hooton Thomas M. , Hodges Andrew P. , He Yongqun , Mobley Harry L. T.
Published: May 2011

Uropathogenic
Escherichia coli
(UPEC) strains, which cause the majority of uncomplicated urinary tract infections (UTIs), carry a unique assortment of virulence or fitness genes. However, no single defining set of virulence or fitness genes has been found in all strains of UPEC, making the differentiation between UPEC and fecal commensal strains of
E. coli
difficult without the use of animal models of infection or phylogenetic grouping. In the present study, we consider three broad categories of virulence factors simultaneously to better define a combination of virulence factors that predicts success in the urinary tract. A total of 314 strains of
E. coli
, representing isolates from fecal samples, asymptomatic bacteriuria, complicated UTIs, and uncomplicated bladder and kidney infections, were assessed by multiplex PCR for the presence of 15 virulence or fitness genes encoding adhesins, toxins, and iron acquisition systems. The results confirm previous reports of gene prevalence among isolates from different clinical settings and identify several new patterns of gene associations. One gene,
tosA
, a putative repeat-in-toxin (RTX) homolog, is present in 11% of fecal strains but 25% of urinary isolates. Whereas
tosA
-positive strains carry an unusually high number (11.2) of the 15 virulence or fitness genes,
tosA
-negative strains have an average of only 5.4 virulence or fitness genes. The presence of
tosA
was predictive of successful colonization of a murine model of infection, even among fecal isolates, and can be used as a marker of pathogenic strains of UPEC within a distinct subset of the B2 lineage.

IMPORTANCE
Escherichia coli
is the primary cause of urinary tract infections, the most common bacterial infection of humans. Virulence of a uropathogenic strain is typically defined by the clinical source of the isolate, the ability to colonize the bladder and kidneys in a murine model, the phylogenetic group of the bacterium, and virulence gene content. Here we describe a novel single gene, the repeat-in-toxin gene
tosA
, the presence of which predicts virulence of
E. coli
isolates regardless of source. Rapid identification of uropathogenic strains of
E. coli
may aid in the development of therapeutic and preventive therapies.
Nanoporous silica colloidal films with molecular transport gated by aptamers responsive to small molecules
Authors: Abelow Alexis E. , White Ryan J. , Plaxco Kevin W. , Zharov Ilya
Published: May 2011

We report the preparation of colloidal nanoporous silica films whose function mimics that of protein channels in gating the transport of small molecules across a cell membrane. Specifically, we report a means of controlling the molecular flux through colloidal nanopores that employ aptamer oligonucleotides binding to a specific organic small molecule (cocaine). These biomacromolecules have been introduced onto the nanopore surface by attaching pre-made oligonucleotides to the activated nanopore surface. The aptamers change their conformation in response to the binding events, and thus alter the free volume of the colloidal nanopores available for molecular transport.
Interactions of molecular ions with model phospholipid membranes
Authors: Petrov Michal , Cwiklik Lukasz , Jungwirth Pavel
Published: May 2011

The affinities of a series of biologically relevant ions for a hydrated phospholipid membrane were investigated using molecular dynamics simulation. Interactions of molecular ions, such as guanidinium, tetramethylammonium, and thiocyanate with the bilayer were computationally characterized for the first time. Simulations reveal strong ion specificity. On one hand, ions like guanidinium and thiocyanate adsorb relatively strongly to the headgroup region of the membrane. On the other hand, potassium or chloride interact very weakly with the phospholipids and merely act as neutralizing counterions. Calculations also show that these ions affect differently biophysical properties of the membrane, such as lipid diffusion, headgroup hydration and tilt angle.
Changes in anteroposterior patellar tendon diameter support a continuum of pathological changes
Authors: Malliaras Peter , Cook Jill
Published: May 2011

Objectives

A continuum of pathological ultrasound patellar tendon changes from normal tendons, followed by diffuse and then focal change in echogenicity has been proposed. The anteroposterior (AP) diameter of each pathological state and whether change in pathological state is accompanied by change in AP diameter are not known. The aims of this study were to (1) investigate the AP diameter of previously described patellar tendon ultrasound groups (normal, diffuse and focal change in echogenicity) and (2) investigate the change in AP diameter among active volleyball players during a season and whether this corresponds with change in ultrasound group.

Methods

The grey-scale ultrasound pathological groups (normal, diffuse, focal) and AP diameter were measured among 102 volleyball players at the beginning of a season and 58 volleyball players at 6 one-monthly intervals during a 5-month indoor season.

Results

There was a significant ordinal relationship (analysis of variance, Student–Neuman–Keuls post hoc test, p < 0.05) between AP diameter and normal tendons, diffuse and focally abnormal tendons among men (3.4 ± 0.4, 4.9 ± 0.4, 6.5 ± 1.8 mm) and women (3.2 ± 0.4, 4.2 ± 0.4, 4.6 ± 0.7 mm). Tendons that stayed in the same group tended to have a smaller mean change than tendons that changed group.

Conclusions

These findings support the proposed continuum of tendon pathology. Mild patellar tendon thickening (>4.2 mm among men, >4 mm among women) may indicate pathology among active athletes.
Sex and gender issues in competitive sports: investigation of a historical case leads to a new viewpoint: Figure 1
Authors: Ballantyne Kaye N , Kayser Manfred , Grootegoed J Anton
Published: May 2011

Based on DNA analysis of a historical case, the authors describe how a female athlete can be unknowingly confronted with the consequences of a disorder of sex development resulting in hyperandrogenism emerging early in her sports career. In such a situation, it is harmful and confusing to question sex and gender. Exposure to either a low or high level of endogenous testosterone from puberty is a decisive factor with respect to sexual dimorphism of physical performance. Yet, measurement of testosterone is not the means by which questions of an athlete's eligibility to compete with either women or men are resolved. The authors discuss that it might be justifiable to use the circulating testosterone level as an endocrinological parameter, to try to arrive at an objective criterion in evaluating what separates women and men in sports competitions, which could prevent the initiation of complicated, lengthy and damaging sex and gender verification procedures.
Does the way concussion is portrayed affect public awareness of appropriate concussion management: the case of rugby league
Authors: McLellan Tracey L , McKinlay Audrey
Published: May 2011

It is important to identify factors that might adversely affect appropriate medical consultation and management of concussion. One factor that might present a barrier to timely intervention is media portrayal of concussion in sporting events, such as professional rugby league. Accordingly, the current study employed a surveillance method of publicly available broadcast information to establish the incidence rate of probable concussion in the National Rugby League's Telstra Premiership 2010 season and examined how these injury events were shown to be managed with respect to return-to-play procedures. The incident rate for probable concussion was higher than previously reported: 11.10\1000 player hours (95% CI 5.78 to 16.40) and was likely underestimated. Importantly, most injured players were shown to continue playing or return to play despite being visibly concussed and described as such by the commentary team. Although ‘return-to-play decisions’ for professional players are guided by medical assessment, the authors discuss whether the way concussion is portrayed might affect public awareness of appropriate concussion management.
Urinary trichlorophenol levels and increased risk of attention deficit hyperactivity disorder among US school-aged children
Authors: Xu Xiaohui , Nembhard Wendy N , Kan Haidong , Kearney Greg , Zhang Zhi-Jiang , Talbott Evelyn O
Published: May 2011

Background

Trichlorophenols (TCPs) are organochlorine compounds which are ubiquitous in the environment and well known for their carcinogenic effects. However, little is known about their neurotoxicity in humans.

Objectives

Our goal was to examine the association between body burden of TCPs (ie, 2,4,5-TCP and 2,4,6-TCP) and attention deficit hyperactivity disorder (ADHD).

Methods

We calculated ORs and 95% CIs from logistic regression analyses using data from the 1999–2004 National Health and Nutrition Examination Survey (NHANES) to evaluate the association between urinary TCPs and parent-reported ADHD among 2546 children aged 6–15 years.

Results

Children with low levels (<3.58 μg/g) and high levels (≥3.58 μg/g) of urinary 2,4,6-TCP had a higher risk of parent-reported ADHD compared to children with levels below the limit of detection (OR 1.54, 95% CI 0.97 to 2.43 and OR 1.77, 95% CI 1.18 to 2.66, respectively; p for trend=0.006) after adjusting for covariates. No association was found between urinary 2,4,5-TCP and parent-reported ADHD.

Conclusion

Exposure to TCP may increase the risk of behavioural impairment in children. The potential neurotoxicity of these chemicals should be considered in public health efforts to reduce environmental exposures/contamination, especially in countries where organochlorine pesticides are still commonly used.
LITERATURE REVIEW ON LINACs AND FFAGs FOR HADRON THERAPY
Authors: VERDÚ-ANDRÉS SILVIA , AMALDI UGO , FAUS-GOLFE ÁNGELES
Published: May 2011

The document summarizes the recent papers, presentations and other public information on Radio-Frequency (RF) Linear Accelerators (linacs) and Fixed-Field Alternating-Gradient (FFAG) accelerators for hadron therapy. The main focus is on technical aspects of these accelerators. This report intends to provide a general overview of the state-of-the-art in those accelerators which could be used in short and middle-term for treating cancer.
STUDIES OF BREAKDOWN IN A PRESSURIZED RF CAVITY
Authors: BASTANINEJAD M. , ELMUSTAFA A. A. , ANKENBRANDT C. M. , MORETTI A. , POPOVIC M. , YONEHARA K. , KAPLAN D. M. , ALSHARO'A M. , HANLET P. M. , JOHNSON R. P. , KUCHNIR M. , NEWSHAM D. , ROSE D. V. , THOMA C. , WELCH D. R.
Published: May 2011

Microscopic images of the surfaces of metallic electrodes used in high-pressure gas-filled 805 MHz RF cavity experiments1 have been used to investigate the mechanism of RF breakdown.2 The images show evidence for melting and boiling in small regions of ~10 micron diameter on tungsten, molybdenum, and beryllium electrode surfaces. In these experiments, the dense hydrogen gas in the cavity prevents electrons or ions from being accelerated to high enough energy to participate in the breakdown process so that the only important variables are the fields and the metallic surfaces. The distributions of breakdown remnants on the electrode surfaces are compared to the maximum surface gradient E predicted by an ANSYS model of the cavity. The local surface density of spark remnants, proportional to the probability of breakdown, shows a strong exponential dependence on the maximum gradient, which is reminiscent of Fowler-Nordheim behavior of electron emission from a cold cathode. New simulation results have shown good agreement with the breakdown behavior of the hydrogen gas in the Paschen region and have suggested improved behavior with the addition of trace dopants such as SF 6.3 Present efforts are to extend the computer model to include electrode breakdown phenomena and to use scanning tunneling microscopy to search for work function differences between the conditioned and unconditioned parts of the electrodes.
ON SOME ERRORS AND BIAS IN PROTON COMPUTED TOMOGRAPHY
Authors: ERDELYI BELA
Published: May 2011

Novel accelerator technology, including Fixed Field Alternating Gradient Accelerators (FFAG) coupled with medical imaging devices, hold significant promise for enhanced proton therapy. The accuracy and efficiency of proton therapy treatments will see improvements with the implementation of proton computed tomography (pCT), currently under development. Here, we analyze the robustness of the image reconstruction method in pCT with respect to three different error sources and conclude that pCT is inherently resilient with respect to errors in mean ionization potential, discrete sampling of proton trajectories and bias in the limit of large radiation doses.
INJECTION AND EXTRACTION SYSTEMS FOR THE MUON FFAG RING IN THE NEUTRINO FACTORY
Authors: KELLIHER DAVID , MACHIDA SHINJI , ASLANINEJAD M. , PASTERNAK J. , BERG J. SCOTT , WITTE H.
Published: May 2011

Non-scaling FFAG (NS-FFAG) rings have been proposed as a solution for muon acceleration in the Neutrino Factory. In order to achieve small orbit excursion and small time of flight variation, lattices with a very compact cell structure and consequent short straight sections are required. The resulting geometry, combined with the large transverse emittance of the muon bunch, places very challenging constraints on the injection/extraction systems. The injection/extraction system requires a set of distributed kickers, a superconducting septum and increased aperture in some of the main ring magnets. A scheme for both injection and extraction for a FFAG with triplet geometry is presented. In addition, a solution for the required kicker magnets is proposed.
S-CODE FOR FIXED FIELD ALTERNATING GRADIENT ACCELERATOR DESIGN AND PARTICLE TRACKING
Authors: MACHIDA SHINJI
Published: May 2011

The constant field nature of a fixed field alternating gradient (FFAG) accelerator requires a modeling which separates the layout of accelerator elements from the geometry of beam orbits. A new code, named s -code, is made to design an FFAG accelerator and to track a beam in it. We will describe the model of accelerator elements and the way to integrate the equation of motion of a particle.
HIGH-ORDER OUT-OF-PLANE EXPANSION FOR 3D FIELDS
Authors: MAKINO K. , BERZ M. , JOHNSTONE C.
Published: May 2011

The precise determination of the dynamics in accelerators with complicated field arrangements such as Fixed Field Alternating Gradient accelerators (FFAG) depends critically on the ability to describe the appearing magnetic fields in full 3D. However, frequently measurements or models of FFAG fields postulate their behavior in the midplane only, and rely on the fact that this midplane field and its derivatives determine the field in all of space. The detailed knowledge of the resulting out-of-plane fields is critical for a careful assessment of the vertical dynamics.

We describe a method based on the differential algebraic (DA) approach to obtain the resulting out-of-plane expansions to any order in an order-independent, straightforward fashion. In particular, the resulting fields satisfy Maxwell's equations to the order of the expansion up to machine precision errors, and without any inaccuracies that can arise from conventional divided difference or finite element schemes for the computation of out-of-plane fields.

The method relies on re-writing the underlying PDE as a fixed point problem involving DA operations, and in particular the differential algebraic integration operator. We illustrate the performance of the method for a variety of practical examples, and obtain estimates for the orders necessary to describe the fields to a prescribed accuracy.
UPGRADING EMMA TO USE LOW-FREQUENCY RF CAVITIES
Authors: OHMORI CHIHIRO , BERG J. SCOTT
Published: May 2011

EMMA is an experiment to study beam dynamics in fixed field alternating gradient accelerators (FFAGs). It accelerates the beam in about 10 turns using 1.3 GHz cavities in a mode like that used for muon accelerators. Many applications of FFAGs prefer to have slower acceleration, typically thousands of turns. To do so in EMMA would require the RF system to be replaced with a low-frequency, high-gradient system. This paper describes the motivation for studying slow acceleration in EMMA and the required parameters for an RF system to do that. It then describes the technology needed for the RF system.
CROSSING RESONANCES IN A NON-SCALING FFAG
Authors: TRBOJEVIC D. , BLASKIEWICZ M. , FOREST E.
Published: May 2011

There are many possible applications for the non-scaling Fixed Field Alternating Gradient (NS-FFAG): accelerating non-relativistic ions, ion cancer therapy, proton drivers, accelerator driven subcritical reactors, heavy radioactive ions, recirculating linacs, and etc. They are confronted with two significant challenges: first is crossing integer resonances as the tunes vary with energy, and that the required fast acceleration has not yet been achieved in practice. An example of a small 30–250 MeV NS-FFAG proton accelerator is used to study both problems. After an introduction, the second chapter shows theoretical predictions for the emittance blow up from crossing the integer resonances. In the third part, the lattice of the ring is briefly described. The fourth chapter describes the "phase jump" a method for fast proton acceleration, while in the chapter five a six dimensional simulations of acceleration is described, ending with conclusions.
STATIONARY BUCKET ACCELERATION IN THE SCALING FFAG ACCELERATOR
Authors: YAMAKAWA E. , UESUGI T. , MORI Y.
Published: May 2011

Stationary bucket acceleration in the scaling type of fixed field alternating gradient (FFAG) accelerator is examined in this paper.
STATUS OF PAMELA: AN UK PARTICLE THERAPY FACILITY PROJECT USING NS-FFAG
Authors:   on behalf of PAMELA Collaboration, YOKOI TAKEICHIRO
Published: May 2011

PAMELA(Particle Accelerator for Medical Application) aims to design a particle therapy facility using NS-FFAG(Non-Scaling Fixed Field Alternating Gradient) accelerator. A newly proposed lattice design and the new type of combined function magnet provide the accelerator flexible tuneability of operating point and variability in operation modes. A remarkable features for a fixed field accelerator are its high repetition rate, about 1 kHz, and energy variable beam extraction. These features make the machine a promising candidate of versatile accelerator not restricted to medical applications.
LINEARIZATION OF RF POWER AMPLIFIERS USING ADAPTIVE KALMAN FILTERING ALGORITHM
Authors: BACHIR SMAIL , CALINOIU NICUSOR , DUVANAUD CLAUDE
Published: May 2011

In this paper, a new linearization algorithm of power amplifier (PA), based on Kalman filtering theory is proposed for obtaining fast convergence of the adaptive digital predistortion. The proposed method uses the real-time digital processing of baseband signals to compensate the nonlinearities and memory effects in radio-frequency power amplifier. To reduce the complexity of computing in classical Kalman filtering, a sliding time-window has been inserted which combines offline measurement and online parameter estimation with high sampling time to track the changes in the PA characteristics. The performance of the proposed linearization scheme is evaluated through simulation and experiments. Using digital signal processing, experimental results with commercial power amplifier are presented for multicarrier signals to demonstrate the effectiveness of this new approach.
AND-OR-XOR NETWORK SYNTHESIS WITH AREA-POWER TRADE-OFF
Authors: PRADHAN SAMBHU NATH , KUMAR M. TILAK , CHATTOPDHYAY SANTANU
Published: May 2011

In this paper, a heuristic based on genetic algorithm to realize multi-output Boolean function as three-level AND-OR-XOR network performing area power trade-off is presented. All the previous works dealt with the minimization of number of product terms only in the two sum-of-product-expressions representing a Boolean function during AND-OR-XOR network synthesis. To the best of knowledge this is the first ever effort to incorporate total power, that is, dynamic and leakage power along with the area (in terms of number of product terms) during three-level AND-OR-XOR networks synthesis. The synthesis process, without changing the delay performance results in lesser number of product terms compared to those reported in the literature. It also enumerates the trade-offs present in the solution space for different weights associated with area, dynamic power, and leakage power of the resulting circuit.
A NOVEL REVERSIBLE ZS GATE AND ITS APPLICATION FOR OPTIMIZATION OF QUANTUM ADDER CIRCUITS
Authors: ZHOU RIGUI , SHI YANG , ZHANG MANQUN , WANG HUI'AN
Published: May 2011

The key of optimizing quantum reversible logic lies in automatically constructing quantum reversible logic circuits with the minimal quantum cost. This paper constructs a 4 × 4 reversible gate called ZS gate to build quantum full adder. At the same time, a novel reversible No-Wait-Carry adder (or carry skip adder) by using ZSCGPD based on ZS gate with the least cost is also designed. The adder circuit using the proposed ZSCGPD is much better and optimized than other researchers' counterparts both in terms of garbage outputs, number and kind of reversible gates, and quantum cost. In order to show the efficiency of the proposed designs, lower bounds of the reversible carry skip adder in terms of garbage outputs and quantum cost are proposed as well.
PRIORITY-DRIVEN AREA OPTIMIZATION IN HIGH-LEVEL SYNTHESIS
Authors: SAAD MARIA ABI , OUAISS IYAD
Published: May 2011

One of the major enhancements that can be made to the high-level synthesis (HLS) process is reducing the overall area of a design in order to either decrease the manufacturing costs or to introduce more functionality to the circuit. Optimizing the area of the datapath is considered a primary field of research in HLS. This work proposes an approach to reduce the area in field programmable gate array (FPGA) by simultaneously tackling the three central tasks of HLS. Scheduling, allocation, and binding are performed and the optimal solution based on area reduction is obtained by using simulated annealing with a priority function. The aim of the priority function is to guide the simulated annealing process into finding the best solution while at the same time incurring the least possible execution time. In order to achieve better results than the initial solution, rescheduling, swapping operations between functional units, swapping variables between registers, and swapping inputs to functional units are considered in the annealing process. A cost function is devised to evaluate a potential move's success or failure. The simulation environment "Eridanus" has been developed in order to support implementation and testing. Several benchmarks were tested and the numerical results consisting of the execution time along with the best solution were recorded to illustrate the performance of the proposed technique. Area reduction was obtained compared to the conventional HLS flow; furthermore, an average substantial reduction in design space exploration time was obtained compared to non-priority based area optimization techniques.
PALATINI APPROACH TO MODIFIED GRAVITY: f(R) THEORIES AND BEYOND
Authors: OLMO GONZALO J.
Published: May 2011

We review the recent literature on modified theories of gravity in the Palatini approach. After discussing the motivations that lead to consider alternatives to Einstein's theory and to treat the metric and the connection as independent objects, we review several topics that have been recently studied within this framework. In particular, we provide an in-depth analysis of the cosmic speed-up problem, laboratory and solar system tests, the structure of stellar objects, the Cauchy problem, and bouncing cosmologies. We also discuss the importance of going beyond the f(R) models to capture other phenomenological aspects related with dark matter/energy and quantum gravity.
THE EFFECT OF PREGNANCY AND POSTPARTUM RECOVERY ON THE VISCOELASTIC BEHAVIOR OF THE RAT CERVIX
Authors: BARONE WILLIAM R. , FEOLA ANDREW J. , MOALLI PAMELA A. , ABRAMOWITCH STEVEN D.
Published: May 2011

The objective of this study was to elucidate the normal functional adaptations of the cervix in pregnancy. Utilizing a Long-Evans rodent model, the cervix was divided into distal and proximal portions for virgin, mid-pregnant, and four weeks postpartum animals. The quasi-linear viscoelastic theory describes the elastic and viscous behavior of the cervix. A hydroxyproline assay was used to measure collagen content. The nonlinearity of the elastic response significantly increased throughout the entire cervix during pregnancy when compared to virgin samples (p < 0.05) and was similar to virgin samples postpartum. All viscous behavior, except for the short-term relaxation of the proximal cervix, significantly differed for pregnant specimens (p < 0.05) and remained similar to pregnant samples postpartum. Collagen content was found to increase by mid-pregnancy only in the proximal cervix when compared to virgin. Distal and proximal portions, however, were found to differ in collagen content at all time points (p < 0.05). This study finds that the cervix becomes elastically stiffer with increasing strain and exhibits increased viscous behavior during pregnancy, with incomplete recovery postpartum. These alterations allow for quick dissipation of loads, and are likely related to altered matrix organization and porosity reported by others.
DIABETES MELLITUS: ENQUIRY INTO ITS MEDICAL ASPECTS AND BIOENGINEERING OF ITS MONITORING AND REGULATION
Authors: ACHARYA U RAJENDRA , GHISTA DHANJOO N , NERGUI MYAGMARBAYAR , CHATTOPADHYAY SUBHAGATA , NG E Y K , SREE S VINITHA , TONG JASPER W K , TAN JEN HONG , MENG LOH KAH , SURI JASJIT S
Published: May 2011

Diabetes mellitus (DM) or hyperglycemia (in a more generalized term, high blood sugar) is a metabolic disorder that is now highly prevalent in the world population. Most of the food that people consume is converted into glucose, which enters the bloodstream following absorption–assimilation mechanisms. As a natural process, cells in our body utilize glucose for growth and energy. The glucose balance is maintained by a hormone called insulin that is secreted by the beta cells of pancreas. Hypotheses at the backdrop of DM occurrence are either (i) enough insulin is not produced and secreted resulting in increased level of glucose in blood, or (ii) insulin is insensitive to glucose, or (iii) insulin is non-targeted etc. If DM remains uncontrolled over time, it leads to serious damage to many of the body's systems, especially the nerves and blood vessels. This paper develops an enquiry into diabetes from many angles: (i) Diabetes as a disorder, its complications, causes, diagnostic tests, and treatment; (ii) Analysis of retinal and plantar images to characterize diabetes complications; (iii) How analysis of heart rate variability signals can depict diabetes; (iv) Biomedical engineering of the glucose–insulin regulatory system, and its employment in the modeling of the oral glucose tolerance test data, to detect diabetes as well as persons at risk of being diabetic; (v) Application of the glucose–insulin regulatory system to formulate an insulin delivery system for controlling blood sugar.
ON THE WAVE EQUATION WITH QUADRATIC NONLINEARITIES IN THREE SPACE DIMENSIONS
Authors: GRÜNROCK AXEL
Published: May 2011

The Cauchy problem for the nonlinear wave equation [Formula: see text] in three space dimensions is considered. The data (u0, u1) are assumed to belong to [Formula: see text], where [Formula: see text] is defined by the norm [Formula: see text] Local well-posedness is shown in the parameter range 2 ≥ r > 1, [Formula: see text]. For r = 2 this coincides with the result of Ponce and Sideris, which is optimal on the Hs-scale by Lindblad's counterexamples, but nonetheless leaves a gap of ½ derivative to the scaling prediction. This gap is closed here except for the endpoint case. Corresponding results for □u = ∂u2 are obtained, too.
A NEW LAGRANGIAN FORMULATION OF IDEAL MAGNETOHYDRODYNAMICS
Authors: DESPRÉS BRUNO
Published: May 2011

We propose a reformulation of ideal magnetohydrodynamics written in the Lagrangian variable as an enlarged system of hyperelastic type, with a specific potential. We study the hyperbolicity of the model and prove that the acoustic tensor is positive for all directions which are non orthogonal to the magnetic field. The consequences for Eulerian ideal magnetohydrodynamics and for numerical discretization are briefly discussed.
CONVERGENCE RATES TO ASYMPTOTIC PROFILE FOR SOLUTIONS OF QUASILINEAR HYPERBOLIC EQUATIONS WITH LINEAR DAMPING
Authors: GENG SHIFENG
Published: May 2011

This paper is concerned with the asymptotic behavior of the solution of quasilinear hyperbolic equations with linear damping. The main novelty lies in the following observation: If we suitably choose the initial data of the corresponding parabolic equation, then the solution Ψ = Ψ(x, t) of the parabolic equation served as the new asymptotic profile satisfies ‖(V-Ψ, (V-Ψ)x, (V-Ψ)t)(t)‖L∞ = O(1)(t-2, t-5/2, t-3). The convergence rates of the new profile Ψ are better than that obtained by H.-J. Zhao (2000, J. Differential Equations167, 467–494), and we need none of the additional technical assumptions (H1) and (H2) therein. Therefore, we answer an open problem posed by Nishihara (1997, J. Differential Equations133, 384–395).
A POROUS VANADIUM PENTOXIDE MATERIAL AND ITS ELECTROCHEMICAL PROPERTIES IN AQUEOUS ELECTROLYTE
Authors: LI ZHAOHUI , TANG JIAOJUN , YANG JIE , CHENG CHENG , XIAO QIZHEN , LEI GANGTIE
Published: May 2011

A porous vanadium pentoxide ( V2O5 ) material was prepared through a facile sol-gel route using β-cyclodextrin (β-CD) as template reagent. Its crystal structure and morphology were characterized by X-ray diffraction and scanning electron microscopy, respectively. The electrochemical properties of the as-prepared V2O5 in 1.0 mol l-1 Li2SO4 aqueous electrolyte were investigated by galvanostatic charging/discharging and cyclic voltammetry. The results revealed that the porous V2O5 could deliver the average capacities of 67, 54 and 42 mAh g-1 at the rates of 0.1, 0.5 and 2 C, respectively. The cycling performances of the V2O5/LiMn2O4 cells suggested that the porous V2O5 material could be used as an anode material for aqueous rechargeable lithium-ion batteries.
HIGHLY CATALYTIC ACTIVE NANOSTRUCTURED Pt ELECTRODES FOR DYE-SENSITIZED SOLAR CELLS PREPARED BY LOW TEMPERATURE ELECTRODEPOSITION
Authors: LIN HONG , HAO FENG , LIN CHUN FU , LI JIAN BAO , WANG NING
Published: May 2011

Highly catalytic active nanostructured Pt electrodes (NPEs) for dye-sensitized solar cells (DSCs) are prepared on indium-doped tin oxide (ITO) conductive glasses using a nonionic surfactant-assisted low-temperature electrodeposition method with controlled quantity of electroplating charge. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) show that the NPEs on ITO conductive glass are composed of nano-sized Pt particles with a diameter of 3–4 nm. Remarkably, with a similar thickness of ca. 38 nm, the NPE shows a charge-transfer resistance (R ct ) of 0.063 Ω ⋅ cm 2, a value almost 20 times lower than that of the sputtered Pt electrode, demonstrating the superior catalytic activity of the NPE. Furthermore, with almost half of the Pt loading, DSC device with NPE exhibits comparable photovoltaic performance with the conventionally sputtered Pt electrode.
VERY HIGH TUNABILITY OF BaSnxTi1-xO3 FERROELECTRIC THIN FILMS DEPOSITED BY SOL-GEL
Authors: MASCOT MANUEL , FASQUELLE DIDIER , CARRU JEAN-CLAUDE
Published: May 2011

Ba(Sn0.02Ti0.98)O3 thin films (BTS) were prepared by sol-gel route and deposited by spin-coating on commercial Pt/Ti/SiO2/Si substrates. By modifying the annealing conditions from 750°C for 1 h to 950°C for 15 min, the grain size increased from 60 nm to 110 nm due to the increased driving force. The dielectric permittivity ε′ and tunability nr are correlated with the grain size: these parameters increase with the grain size. At room temperature for the BST film annealed at 950°C, a record value of 76% of tunability is obtained at 10 kHz. This very high value of tunability makes BaSnTiO 3 a very good candidate for tunable devices.
RAPID THERMAL ANNEALING INDUCED ENHANCED BAND-EDGE EMISSION FROM ZnO NANOWIRES, NANORODS AND NANORIBBONS
Authors: DHARA SOUMEN , GIRI P. K.
Published: May 2011

In this letter, we report on the enhanced near band edge (NBE) photoluminescence (PL) emission by rapid thermal annealing (RTA) of ZnO nanowires, nanoribbons and nanorods synthesized by vapor transport method using a ZnO nanopowder source. As a result of RTA, the intensity ratio of NBE to green emission peak is nearly doubled for the nanowires, while this enhancement is one order of magnitude for the nanoribbons and nanorods. Time-resolved PL studies on the green emission band shows a single-exponential decay (time constant ~ns) after RTA. The Raman spectral shift of the RTA treated samples indicates reduced tensile strain in the annealed ZnO nanostructures. Our results demonstrate the effectiveness of RTA process for improving the crystallinity and optical properties of ZnO nanostructures.
ELECTRIC, MAGNETIC AND MECHANICAL COUPLING EFFECTS ON FERROELECTRIC PROPERTIES AND SURFACE POTENTIAL OF BiFeO3 THIN FILM
Authors: KUMAR AMIT , YAN FENG , ZENG KAIYANG , LU LI
Published: May 2011

BiFeO 3 (BFO) is usually considered as a multiferroic material, which shows both ferroelectric and antiferromagnetic properties at room temperature. It is an important material having potential applications in various spintronics devices. Many studies have been done to understand the ferroelectric and magnetic responses of BFO; therefore, this work is focused on characterizing the coupling effects of electric, magnetic and mechanical field on the ferroelectric properties and surface potential of the BFO thin films. A polycrystalline BFO film (~200 nm) is deposited on the Si substrate by the Pulse Laser Deposition techniques. The Vertical Piezoresponse Force Microscopy (PFM) is used to study the ferroelectric domain structure and the hysteresis loop of as-deposited BFO film as well as the effects of the mechanical stress and magnetic field on those properties. Kelvin Probe Force Microscopy (KPFM) is used to measure the surface potential of the samples. To apply the mechanical stress on the film, micro-indentations were made on the surface of the film with two different loads (1.96 N, 2.94 N). Then the ferroelectric domain structure, strain amplitude, domain switching (hysteresis response) behavior and surface potential are measured at the locations near the side of the indentation cavity and cracks. This way, the coupling effects of electric, magnetic and stress field on BFO film are studied at nanoscale.
MILD SOLUTION ROUTE TO MIXED-PHASE MnO2 WITH ENHANCED ELECTROCHEMICAL CAPACITANCE
Authors: CUI DEYUAN , GAO KUN , LU PAI , YANG HONG , LIU YINONG , XUE DONGFENG
Published: May 2011

Mild chemical bath route at 60–80°C led to the redox reaction between MnSO 4 and KMnO 4 to form MnO 2. The as-synthesized MnO 2 was a mixture of both α- and δ-phases, which has enhanced electrochemical capacitance performances. Pure α-, δ- and γ- MnO 2 were also chemically prepared in the current solution system. The electrochemical performances of the as-prepared MnO 2 samples were evaluated as an electrode for supercapacitor by recording cyclic voltammograms and galvanostatic charge-discharge curves. The crystallographic structure of MnO2 was found to be determined by the chemical bath reaction temperature and time. In the current work, we purposefully designed the optimum reaction parameters to synthesize high performance mixed-phase MnO 2 through mild chemical bath route, ultimately for enhancing the capacitance of powder-based electrodes.
SINGLE-PHASED AND EMISSION-TUNABLE CaLa2-xEuxZnO5 PHOSPHORS WITH BLUE LIGHT EXCITATION FOR WLEDS
Authors: BANDI VENGALA RAO , GRANDHE BHASKAR KUMAR , JANG KIWAN , LEE HO-SUEB , YI SOUNG-SOO , JEONG JUNG-HYUN
Published: May 2011

Single-phased and emission-tunable CaLa2-xEuxZnO5 phosphors were synthesized by citric sol-gel method. Precisely adjusting the activator concentration in CaLa2ZnO5 (CLZ) phosphor, we could obtain blue-green (BG) to orange-red (OR) emissions from the 5 D 2, 1, 0 → 7 FJ levels of Eu 3+ with the blue excitation wavelength of 468 nm, which perfectly matches with the emission of blue LED chip. This fascinating result has provoked us to blend the green and red color tunable single phased phosphors with and without YAG: Ce to fabricate blue LED based white light emitting diodes (LED). The emission features thus interpreted are appropriately explained through their chromaticity coordinates and energy level diagram. Besides, its thermal stability is also investigated.
Aspects of crinoid palaeontology, Much Wenlock Limestone Formation, Wenlock Edge, Shropshire (Silurian)
Authors: Donovan S. K. , Lewis D. N.
Published: May 2011

Fossil crinoids are common in the Much Wenlock Limestone Formation of the type area in Shropshire, yet remain poorly known because of their fragmentary preservation. Calceocrinid disparids are recognized from Wenlock Edge for the first time on the basis of distinctive brachial ossicles. More proximal brachials have a broad, U-shaped adoral groove and an axial canal; distal ossicles have a narrower, V-shaped adoral groove and no axial canal. What remains surprising is that the most distinctive element of the calceocrinid endoskeleton, the fused basal circlet, remains unknown from Wenlock Edge.

A crinoid pluricolumnal displaying an irregular line of three pits that show a progressive increase in size was infested while the crinoid was alive; this is indicated by the swollen column and deformities of columnals. Such infestations are rare in the British Silurian. The pits may have been made by a single infesting organism which migrated up or down the column in response to the influence of gravity.
Crinoid roots from the Upper Devonian of north Devon: morphology, function and systematics
Authors: Donovan S. K. , Ewin T. A. M.
Published: May 2011

A small collection of well-preserved crinoid attachment structures from the Upper Devonian Pilton Formation of north Devon indicates the presence of two distinct species.
Sostronocrinus mundus
(Whidborne) lived attached to an unlithified sedimentary substrate by the vertical insertion of a robust, terminal rhizoidal holdfast abetted by robust, unbranched radices oriented laterally or curved distally. There was a strong differentiation of morphology between the radicular attachment and the more proximal column, which lacked radices.
Eumorphocrinus porteri
(Whidborne) attached to a similar substrate by an irregularly heteromorphic, tapering radicular runner bearing branched radices that promoted permanent attachment close to the sediment surface. These radices were probably developed on at least part of the more proximal column. The highest columnals of the dististele do not bear radices and, therefore, are not nodals. The dististele was previously unknown in both of these species.
Using X-ray images to analyse graptolite distribution and alignment in Welsh mudrocks
Authors: Snelling Andrea M. , Zalasiewicz Jan A. , Reeds Ian
Published: May 2011

X-ray imaging of graptolites is here shown to enhance greatly the amount and type of fossil evidence available, both for biostratigraphical study and for palaeoceanographical and palaeoecological analysis. The technique requires there to be sufficient density contrast between the fossils and the enclosing rock, as with the pyritized graptolites within the Silurian (Llandovery, Aeronian) mudrocks of central Wales investigated herein. Graptolite species previously not encountered using traditional collecting techniques were recorded in significant numbers using X-ray imaging and include two species recorded for the first time in Britain. Stratigraphic variation has been found in the numbers of pyritized graptolites, and this is inversely related to the amount of free aggregated pyrite within the rock. Biserial graptolite specimens show systematic patterns of alignment by currents, and construction of stereo and anaglyph images enables 3-dimensional visualisation of spatial information, allowing the geometry and microstratigraphic relationship of one graptolite to another to be discerned. CT-scan techniques show better-resolved 3D morphology, but digital X-ray techniques, being more rapid, may remain optimal for many routine uses in palaeontology.
Role of the USF1 transcription factor in diabetic kidney disease
Authors: Sanchez Amber P. , Zhao JingHong , You Young , Declèves Anne-Emilie , Diamond-Stanic Maggie , Sharma Kumar
Published: May 2011

The predominant transcription factors regulating key genes in diabetic kidney disease have not been established. The transcription factor upstream stimulatory factor 1 (USF1) is an important regulator of glucose-mediated transforming growth factor (TGF)-β1 expression in mesangial cells; however, its role in the development of diabetic kidney disease has not been evaluated. In the present study, wild-type (WT; USF1 +/+), heterozygous (USF1 +/−), and homozygous (USF1 −/−) knockout mice were intercrossed with Akita mice (Ins2/Akita) to induce type 1 diabetes. Mice were studied up to 36 wk of age. The degree of hyperglycemia and kidney hypertrophy were similar in all groups of diabetic mice; however, the USF1 −/− diabetic mice had significantly less albuminuria and mesangial matrix expansion than the WT diabetic mice. TGF-β1 and renin gene expression and protein were substantially increased in the WT diabetic mice but not in USF1 −/− diabetic mice. The underlying pathway by which USF1 is regulated by high glucose was investigated in mesangial cell culture. High glucose inhibited AMP-activated protein kinase (AMPK) activity and increased USF1 nuclear translocation. Activation of AMPK with AICAR stimulated AMPK activity and reduced nuclear accumulation of USF1. We thus conclude that USF1 is a critical transcription factor regulating diabetic kidney disease and plays a critical role in albuminuria, mesangial matrix accumulation, and TGF-β1 and renin stimulation in diabetic kidney disease. AMPK activity may play a key role in high glucose-induced regulation of USF1.
Live imaging of bulk endocytosis in frog motor nerve terminals using FM dyes
Authors: Gaffield Michael A. , Romberg Christin F. , Betz William J.
Published: May 2011

We observed endocytosis in real time in stimulated frog motor nerve terminals by imaging the growth of large membrane infoldings labeled with a low concentration of FM dye. The spatial and temporal information made available by these experiments allowed us to image several new aspects of this synaptic vesicle recycling pathway. Membrane infoldings appeared near synaptic vesicle clusters and grew rapidly during long-duration, high-frequency stimulation. In some cases, we observed large, elongated infoldings growing laterally into the terminal. We used these observations to calculate infolding growth rates. A decrease in stimulation frequency caused a decrease in growth rates, but the overall length of these structures was unaffected by frequency changes. Attempts to wash the dye from these infoldings after stimulation were unsuccessful, demonstrating that the fluorescent structures had been endocytosed. We also used this technique to trigger and image infoldings during repeated, short trains. We found that membrane uptake occurred repeatedly at individual endocytosis sites, but only during a portion of the total number of trains delivered to the terminal. Finally, we showed that phosphatidylinositol 3-kinase, but not actin, was involved in this endocytosis pathway. The ability to monitor many individual bulk endocytosis sites in real time should allow for new types of endocytosis measurements and could reveal novel and unexpected mechanisms for coordinating membrane recovery during synaptic activity.
Metabolic cycles in a circannual hibernator
Authors: Epperson L. Elaine , Karimpour-Fard Anis , Hunter Lawrence E. , Martin Sandra L.
Published: May 2011

Hibernation as manifested in ground squirrels is arguably the most plastic and extreme of physiological phenotypes in mammals. Homeostasis is challenged by prolonged fasting accompanied by heterothermy, yet must be facilitated for survival. We performed LC and GC-MS metabolomic profiling of plasma samples taken reproducibly during seven natural stages of the hibernator's year, three in summer and four in winter (each n ≥ 5), employing a nontargeted approach to define the metabolite shifts associated with the phenotype. We quantified 231 named metabolites; 106 of these altered significantly, demarcating a cycle within a cycle where torpor-arousal cycles recur during the winter portion of the seasonal cycle. A number of robust hibernation biomarkers that alter with season and winter stage are identified, including specific free fatty acids, antioxidants, and previously unpublished modified amino acids that are likely to be associated with the fasting state. The major pattern in metabolite levels is one of either depletion or accrual during torpor, followed by reversal to an apparent homeostatic level by interbout arousal. This finding provides new data that strongly support the predictions of a long-standing hypothesis that periodic arousals are necessary to restore metabolic homeostasis.
The champions' mitochondria: is it genetically determined? A review on mitochondrial DNA and elite athletic performance
Authors: Eynon Nir , Morán María , Birk Ruth , Lucia Alejandro
Published: May 2011

Aerobic ATP generation by the mitochondrial respiratory oxidative phosphorylation system (OXPHOS) is a vital metabolic process for endurance exercise. Notably, mitochondrial DNA (mtDNA) codifies 13 of the 83 polypeptides implied in the respiratory chain. As such, there is a strong rationale for identifying an association between mtDNA variants and “aerobic” (endurance) exercise phenotypes. The aim of this review is to summarize current knowledge on the association between mtDNA, nuclear genes involved in mitochondriogenesis, and elite endurance athletic status. Several studies in nonathletic people have demonstrated an association between certain mtDNA lineages and aerobic performance, characterized by maximal oxygen uptake (V̇o2max). Whether mtDNA haplogroups are also associated with the status of being an elite endurance athlete is more controversial, with differences between studies arising from the different ethnic backgrounds of the athletic cohorts (Caucasian of mixed geographic origin, Asiatic, or East African).