bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical modeling of three-dimensional underwater sound propagation under rough sea surfaces
Authors: Lin Ying-Tsong
Published: May 2014

A three-dimensional parabolic-equation (PE) solution of long-distance underwater sound propagation with the influence of arbitrary sea surface roughness is derived. A stair-step approximation is implemented to the sea surface height along the PE solution marching direction. A higher-order operator splitting algorithm is utilized for an Alternative Direction Implicit (ADI) method to achieve computational efficiency and accuracy. The ADI method also ensures that the pressure release interface condition on the irregular sea surface is satisfied exactly. An theoretical solution will be used to benchmark the PE solution, and examples of sound propagation under sea surface wave swells will be shown. Depending on the source position relative to the waves, the acoustic waveguide condition can change from ducting to anti-ducting. Two-way PE solutions to include acoustic back-scattering from rough sea surfaces will also be discussed. [Work supported by the ONR.]
An investigation into the bottom interface treatment in parabolic equation models utilizing split-step Fourier and finite-difference algorithms
Authors: Smith Kevin B. , Thomson David J. , Hursky Paul
Published: May 2014

Recent analysis of parabolic equation model results computed using split-step Fourier algorithms have shown increasing phase errors at long range in simple, isospeed waveguides. Preliminary results suggest that these errors are due to the treatment of the density discontinuity at the water/bottom interface through the use of smoothing functions. In this work, several different approaches are investigated for improving the phase accuracy of the solution, including hybrid methods employing split-step Fourier and finite-difference algorithms, as well as equivalent bottom characterizations. The results are compared relative to their improvements in accuracy as well as computational efficiency.
Weakly dispersive modal pulse propagation in the North Pacific Ocean
Authors: Udovydchenkov Ilya A. , Brown Michael G. , Duda Timothy F. , Worcester Peter F. , Dzieciuch Matthew A. , Mercer James A. , Andrew Rex K. , Howe Bruce M. , Colosi John A.
Published: May 2014

The propagation of weakly dispersive modal pulses is investigated using data collected during the 2004 long-range ocean acoustic propagation experiment (LOAPEX). Weakly dispersive modal pulses are characterized by weak dispersion- and scattering-induced pulse broadening; such modal pulses experience minimal propagation-induced distortion and are thus well suited to communications applications. In the LOAPEX environment, modes 1, 2, and 3 are approximately weakly dispersive. Using LOAPEX observations it is shown that, by extracting the energy carried by a weakly dispersive modal pulse, a transmitted communications signal can be recovered without performing channel equalization at ranges as long as 500 km; at that range a majority of mode 1 receptions have bit error rates (BERs) less than 10%, and 6.5% of mode 1 receptions have no errors. BERs are estimated for low order modes and compared with measurements of signal-to-noise ratio (SNR) and modal pulse spread. Generally, it is observed that larger modal pulse spread and lower SNR result in larger BERs. [Work supported by ONR.]
Results from England’s 2014 Report Card on Physical Activity for Children and Youth
Authors: Standage Martyn , Wilkie Hannah J. , Jago Russell , Foster Charlie , Goad Mary A. , Cumming Sean P.
Published: May 2014

Background:

The Active Healthy Kids 2014 England Report Card aims to provide a systematic assessment of how England is performing in relation to engaging and facilitating physical activity (PA) in children and young people.

Methods:

The systematic methods and processes that underpin the Active Healthy Kids Canada Report Card were used and adapted. Data and evidence were consolidated, reviewed by a panel of content experts, and used to inform the assignment of letter grades (A, B, C, D, F) to 9 core indicators related to PA.

Results:

Children’s Overall Physical Activity received a grade of C/D. Active Transportation and Organized Sport Participation received grades of C and C-, respectively. The indicators of School and Community and the Built Environment were graded favorable with grades of A- and B, respectively. Active Play, Sedentary Behaviors, Family and Peers, and Government Strategies and Investments were graded as INC (incomplete) due to a lack of nationally representative data and/or as a result of data not mapping onto the benchmarks used to assign the grades.

Conclusions:

Substantial provision for PA opportunities in England exists. Yet more effort is required to maximize use of these resources to increase PA participation.
Results from Colombia’s 2014 Report Card on Physical Activity for Children and Youth
Authors: González Silvia A. , Sarmiento Olga L. , Cohen Daniel D. , Camargo Diana M. , Correa Jorge E. , Páez Diana C. , Ramírez-Vélez Robinson
Published: May 2014

Background:

Physical activity (PA) is central to the global agenda for the prevention on noncommunicable diseases (NCDs). Although 80% of NCDs occur in low-to-middle-income countries, the evidence on PA comes mainly from high-income countries. In this context, the report card for Colombia is an advocacy tool to help in the translation of evidence into concrete actions. The aims of this paper were two-fold: to present the methodology used to develop the first Report Card on Physical Activity in Colombian Children and Youth and to summarize the results.

Methods:

Twelve indicators of PA were graded using numerical grades (5, highest, to 1, lowest) based on data from national surveys and policy documents.

Results:

National policy and obesity indicators were graded “4,” while departmental policy and overweight indicators were graded “3.” Overall PA levels, sports participation, sedentary behaviors and nongovernment initiatives were graded “2,” and school influence was graded “1.” Active transportation, active play, low cardiorespiratory fitness, and family and community influence received an incomplete.

Conclusion:

PA levels are low and sedentary behaviors are high in Colombian children and youth. Although the prevalence of obesity in Colombia is lower compared with other Latin American countries, it is increasing. A rich legal framework and availability of institutional arrangements provide unique opportunities to bridge the gap between knowledge and practice that need to be evaluated.
Perception of Effort Changes Following an Isometric Fatiguing Exercise of Elbow Flexors
Authors: Lampropoulou Sofia I. , Nowicky Alexander V.
Published: May 2014

The way psychometric and neurophysiological measurements of fatigue are connected is not well understood. Thus, the time course of perceived effort changes due to fatigue, as well as the peripheral and central neurophysiological changes accompanying fatigue, were evaluated. Twelve healthy participants (35 ± 9 years old) undertook 10 min intermittent isometric fatiguing exercise of elbow flexors at 50% of maximum voluntary contraction (MVC). Perceived effort ratings, using the 0–10 numeric rating scale (NRS), were recorded at midrange of MVC. Single pulse TMS of the left motor cortex and electrical stimulation over the biceps muscle was used for the assessment of voluntary activation and peripheral fatigue. The fatiguing exercise caused a 44% reduction in the MVC (p < .001) accompanied by an 18% nonsignificant reduction of the biceps MEP amplitude. The resting twitch force decreased (p < .001) while the superimposed twitches increased (p < .001) causing a decrease (19%) of the voluntary activation (p < .001). The perceived effort ratings increased by 1 point at 30%, by 2 points at 50% MVC respectively on the NRS (p < .001) and were accompanied by an increase in mean biceps EMG. A substantial role of the perceived effort in the voluntary motor control system was revealed.
Targeting Poly(ADP-Ribose) Polymerase and the c-Myb–Regulated DNA Damage Response Pathway in Castration-Resistant Prostate Cancer
Authors: Li Likun , Chang Wenjun , Yang Guang , Ren Chengzhen , Park Sanghee , Karantanos Theodoros , Karanika Styliani , Wang Jianxiang , Yin Jianhua , Shah Parantu K. , Takahiro Hirayama , Dobashi Masato , Zhang Wenling , Efstathiou Eleni , Maity Sankar N. , Aparicio Ana M. , Li Ning Tapia Elsa M. , Troncoso Patricia , Broom Bradley , Xiao Lianchun , Lee Hyun-Sung , Lee Ju-Seog , Corn Paul G. , Navone Nora , Thompson Timothy C.
Published: May 2014

The DNA damage response is an appealing target for androgen inhibitor–resistant prostate cancer.
LL-37-Derived Peptides Eradicate Multidrug-Resistant Staphylococcus aureus from Thermally Wounded Human Skin Equivalents
Authors: Haisma Elisabeth M. , de Breij Anna , Chan Heelam , van Dissel Jaap T. , Drijfhout Jan W. , Hiemstra Pieter S. , El Ghalbzouri Abdoelwaheb , Nibbering Peter H.
Published: May 2014

Burn wound infections are often difficult to treat due to the presence of multidrug-resistant bacterial strains and biofilms. Currently, mupirocin is used to eradicate methicillin-resistant
Staphylococcus aureus
(MRSA) from colonized persons; however, mupirocin resistance is also emerging. Since we consider antimicrobial peptides to be promising candidates for the development of novel anti-infective agents, we studied the antibacterial activities of a set of synthetic peptides against different strains of
S. aureus
, including mupirocin-resistant MRSA strains. The peptides were derived from P60.4Ac, a peptide based on the human cathelicidin LL-37. The results showed that peptide 10 (P10) was the only peptide more efficient than P60.4Ac, which is better than LL-37, in killing MRSA strain LUH14616. All three peptides displayed good antibiofilm activities. However, both P10 and P60.4Ac were more efficient than LL-37 in eliminating biofilm-associated bacteria. No toxic effects of these three peptides on human epidermal models were detected, as observed morphologically and by staining for mitochondrial activity. In addition, P60.4Ac and P10, but not LL-37, eradicated MRSA LUH14616 and the mupirocin-resistant MRSA strain LUH15051 from thermally wounded human skin equivalents (HSE). Interestingly, P60.4Ac and P10, but not mupirocin, eradicated LUH15051 from the HSEs. None of the peptides affected the excretion of interleukin 8 (IL-8) by thermally wounded HSEs upon MRSA exposure. In conclusion, the synthetic peptides P60.4Ac and P10 appear to be attractive candidates for the development of novel local therapies to treat patients with burn wounds infected with multidrug-resistant bacteria.
Impacts of Plant-Based Foods in Ancestral Hominin Diets on the Metabolism and Function of Gut Microbiota
In Vitro
Authors: Frost Gary S. , Walton Gemma E. , Swann Jonathan R. , Psichas Arianna , Costabile Adele , Johnson Laura P. , Sponheimer Matt , Gibson Glenn R. , Barraclough Timothy G.
Published: May 2014

Ancestral human populations had diets containing more indigestible plant material than present-day diets in industrialized countries. One hypothesis for the rise in prevalence of obesity is that physiological mechanisms for controlling appetite evolved to match a diet with plant fiber content higher than that of present-day diets. We investigated how diet affects gut microbiota and colon cells by comparing human microbial communities with those from a primate that has an extreme plant-based diet, namely, the gelada baboon, which is a grazer. The effects of potato (high starch) versus grass (high lignin and cellulose) diets on human-derived versus gelada-derived fecal communities were compared
in vitro
. We especially focused on the production of short-chain fatty acids, which are hypothesized to be key metabolites influencing appetite regulation pathways. The results confirmed that diet has a major effect on bacterial numbers, short-chain fatty acid production, and the release of hormones involved in appetite suppression. The potato diet yielded greater production of short-chain fatty acids and hormone release than the grass diet, even in the gelada cultures, which we had expected should be better adapted to the grass diet. The strong effects of diet on hormone release could not be explained, however, solely by short-chain fatty acid concentrations. Nuclear magnetic resonance spectroscopy found changes in additional metabolites, including betaine and isoleucine, that might play key roles in inhibiting and stimulating appetite suppression pathways. Our study results indicate that a broader array of metabolites might be involved in triggering gut hormone release in humans than previously thought.

IMPORTANCE
One theory for rising levels of obesity in western populations is that the body’s mechanisms for controlling appetite evolved to match ancestral diets with more low-energy plant foods. We investigated this idea by comparing the effects of diet on appetite suppression pathways via the use of gut bacterial communities from humans and gelada baboons, which are modern-day primates with an extreme diet of low-energy plant food, namely, grass. We found that diet does play a major role in affecting gut bacteria and the production of a hormone that suppresses appetite but not in the direction predicted by the ancestral diet hypothesis. Also, bacterial products were correlated with hormone release that were different from those normally thought to play this role. By comparing microbiota and diets outside the natural range for modern humans, we found a relationship between diet and appetite pathways that was more complex than previously hypothesized on the basis of more-controlled studies of the effects of single compounds.
Analysis of Two-Component Systems in Group B
Streptococcus
Shows That RgfAC and the Novel FspSR Modulate Virulence and Bacterial Fitness
Authors: Faralla Cristina , Metruccio Matteo M. , De Chiara Matteo , Mu Rong , Patras Kathryn A. , Muzzi Alessandro , Grandi Guido , Margarit Immaculada , Doran Kelly S. , Janulczyk Robert
Published: May 2014

Group B
Streptococcus
(GBS), in the transition from commensal organisms to pathogens, will encounter diverse host environments and, thus, require coordinated control of the transcriptional responses to these changes. This work was aimed at better understanding the role of two-component signal transduction systems (TCS) in GBS pathophysiology through a systematic screening procedure. We first performed a complete inventory and sensory mechanism classification of all putative GBS TCS by genomic analysis. Five TCS were further investigated by the generation of knockout strains, and
in vitro
transcriptome analysis identified genes regulated by these systems, ranging from 0.1% to 3% of the genome. Interestingly, two sugar phosphotransferase systems appeared to be differentially regulated in the TCS-16 knockout strain (TCS loci were numbered in order of their appearance on the chromosome), suggesting an involvement in monitoring carbon source availability. High-throughput analysis of bacterial growth on different carbon sources showed that TCS-16 was necessary for the growth of GBS on fructose-6-phosphate. Additional transcriptional analysis provided further evidence for a stimulus-response circuit where extracellular fructose-6-phosphate leads to autoinduction of TCS-16, with concomitant dramatic upregulation of the adjacent operon, which encodes a phosphotransferase system. The TCS-16-deficient strain exhibited decreased persistence in a model of vaginal colonization. All mutant strains were also characterized in a murine model of systemic infection, and inactivation of TCS-17 (also known as RgfAC) resulted in hypervirulence. Our data suggest a role for the previously unknown TCS-16, here named FspSR, in bacterial fitness and carbon metabolism during host colonization, and the data also provide experimental evidence for TCS-17/RgfAC involvement in virulence.

IMPORTANCE
Two-component systems have been evolved by bacteria to detect environmental changes, and they play key roles in pathogenicity. A comprehensive analysis of TCS in GBS has not been performed previously. In this work, we classify 21 TCS and present evidence for the involvement of two specific TCS in GBS virulence and colonization
in vivo
. Although pinpointing specific TCS stimuli is notoriously difficult, we used a combination of techniques to identify two systems with different effects on GBS pathogenesis. For one of the systems, we propose that fructose-6-phosphate, a metabolite in glycolysis, is sufficient to induce a regulatory response involving a sugar transport system. Our catalogue and classification of TCS may guide further studies into the role of TCS in GBS pathogenicity and biology.
Uptake of Helicobacter pylori Vesicles Is Facilitated by Clathrin-Dependent and Clathrin-Independent Endocytic Pathways
Authors: Olofsson Annelie , Nygård Skalman Lars , Obi Ikenna , Lundmark Richard , Arnqvist Anna
Published: May 2014

Bacteria shed a diverse set of outer membrane vesicles that function as transport vehicles to deliver effector molecules and virulence factors to host cells.
Helicobacter pylori
is a gastric pathogen that infects half of the world’s population, and in some individuals the infection progresses into peptic ulcer disease or gastric cancer. Here we report that intact vesicles from
H. pylori
are internalized by clathrin-dependent endocytosis and further dynamin-dependent processes, as well as in a cholesterol-sensitive manner. We analyzed the uptake of
H. pylori
vesicles by gastric epithelial cells using a method that we refer to as quantification of internalized substances (qIS). The qIS assay is based on a near-infrared dye with a cleavable linker that enables the specific quantification of internalized substances after exposure to reducing conditions. Both chemical inhibition and RNA interference in combination with the qIS assay showed that
H. pylori
vesicles enter gastric epithelial cells via both clathrin-mediated endocytosis and additional endocytic processes that are dependent on dynamin. Confocal microscopy revealed that
H. pylori
vesicles colocalized with clathrin and dynamin II and with markers of subsequent endosomal and lysosomal trafficking. Interestingly, however, knockdown of components required for caveolae had no significant effect on internalization and knockdown of components required for clathrin-independent carrier (CLIC) endocytosis increased internalization of
H. pylori
vesicles. Furthermore, uptake of vesicles by both clathrin-dependent and -independent pathways was sensitive to depletion, but not sequestering, of cholesterol in the host cell membrane suggesting that membrane fluidity influences the efficiency of
H. pylori
vesicle uptake.

IMPORTANCE
Bacterial vesicles act as long-distance tools to deliver toxins and effector molecules to host cells. Vesicles can cause a variety of host cell responses via cell surface-induced cell signaling or internalization. Vesicles of diverse bacterial species enter host cells via different endocytic pathways or via membrane fusion. With the combination of a fluorescence-based quantification assay that quantifies internalized vesicles in a large number of cells and either chemical inhibition or RNA interference, we show that clathrin-mediated endocytosis is the major pathway for uptake of
Helicobacter pylori
vesicles and that lipid microdomains of the host cell membrane affect uptake of vesicles via clathrin-independent pathways. Our results provide important insights about membrane fluidity and its important role in the complex process that directs the
H. pylori
vesicle to a specific endocytic pathway. Understanding the mechanisms that operate in vesicle-host interactions is important to fully recognize the impact of vesicles in pathogenesis.
The Bacterial Phosphoenolpyruvate:Carbohydrate Phosphotransferase System: Regulation by Protein Phosphorylation and Phosphorylation-Dependent Protein-Protein Interactions
Authors: Deutscher Josef , Aké Francine Moussan Désirée , Derkaoui Meriem , Zébré Arthur Constant , Cao Thanh Nguyen , Bouraoui Houda , Kentache Takfarinas , Mokhtari Abdelhamid , Milohanic Eliane , Joyet Philippe
Published: May 2014

The bacterial phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS) carries out both catalytic and regulatory functions. It catalyzes the transport and phosphorylation of a variety of sugars and sugar derivatives but also carries out numerous regulatory functions related to carbon, nitrogen, and phosphate metabolism, to chemotaxis, to potassium transport, and to the virulence of certain pathogens. For these different regulatory processes, the signal is provided by the phosphorylation state of the PTS components, which varies according to the availability of PTS substrates and the metabolic state of the cell. PEP acts as phosphoryl donor for enzyme I (EI), which, together with HPr and one of several EIIA and EIIB pairs, forms a phosphorylation cascade which allows phosphorylation of the cognate carbohydrate bound to the membrane-spanning EIIC. HPr of firmicutes and numerous proteobacteria is also phosphorylated in an ATP-dependent reaction catalyzed by the bifunctional HPr kinase/phosphorylase. PTS-mediated regulatory mechanisms are based either on direct phosphorylation of the target protein or on phosphorylation-dependent interactions. For regulation by PTS-mediated phosphorylation, the target proteins either acquired a PTS domain by fusing it to their N or C termini or integrated a specific, conserved PTS regulation domain (PRD) or, alternatively, developed their own specific sites for PTS-mediated phosphorylation. Protein-protein interactions can occur with either phosphorylated or unphosphorylated PTS components and can either stimulate or inhibit the function of the target proteins. This large variety of signal transduction mechanisms allows the PTS to regulate numerous proteins and to form a vast regulatory network responding to the phosphorylation state of various PTS components.
Recurrent cardiac tamponade: an initial presentation of lung adenocarcinoma
Authors: Kumar Aditi , Puttanna Amar
Published: May 2014

A 63-year-old hypertensive woman presented initially to the surgical team with right upper quadrant pain, the patient was otherwise asymptomatic and clinically well. An abdominal CT scan excluded any surgical diagnoses but rather showed a pericardial effusion. When the cardiology team urgently reviewed her, they found her to be hypotensive and tachycardic with a raised jugular venous pressure. A diagnosis of cardiac tamponade was made and was transferred to the coronary care unit for an emergency pericardiocentesis. She developed tamponade on further occasions requiring pericardiocentesis. The underlying cause was investigated and following pericardial fluid analysis and subsequent imaging, metastatic lung adenocarcinoma was diagnosed.
A pilot study of an online universal school-based intervention to prevent alcohol and cannabis use in the UK
Authors: Newton Nicola C , Conrod Patricia J , Rodriguez Daniel M , Teesson Maree
Published: May 2014

Objectives

The online universalClimate Schoolsintervention has been found to be effective in reducing the use of alcohol and cannabis among Australian adolescents. The aim of the current study was to examine the feasibility of implementing this prevention programme in the UK.

Design

A pilot study examining the feasibility of theClimate Schoolsprogramme in the UK was conducted with teachers and students from Year 9 classes at two secondary schools in southeast London. Teachers were asked to implement the evidence-basedClimate Schoolsprogramme over the school year with their students. The intervention consisted of two modules (each with six lessons) delivered approximately 6 months apart. Following completion of the intervention, students and teachers were asked to evaluate the programme.

Results

11 teachers and 222 students from two secondary schools evaluated the programme. Overall, the evaluations were extremely positive. Specifically, 85% of students said the information on alcohol and cannabis and how to stay safe was easy to understand, 84% said it was easy to learn and 80% said the online cartoon-based format was an enjoyable way to learn health theory topics. All teachers said the students were able to recall the information taught, 82% said the computer component was easy to implement and all teachers said the teacher's manual was easy to use to prepare class activities. Importantly, 82% of teachers said it was likely that they would use the programme in the future and recommend it to others.

Conclusions

The Internet-based universalClimate Schoolsprevention programme to be both feasible and acceptable to students and teachers in the UK. A full evaluation trial of the intervention is now required to examine its effectiveness in reducing alcohol and cannabis use among adolescents in the UK before implementation in the UK school system.
Extending the value of police crash reports for traffic safety research: collecting supplemental data via surveys of drivers
Authors: Durbin Dennis R , Myers Rachel K , Curry Allison E , Zonfrillo Mark R , Arbogast Kristy B
Published: May 2014

Background

Police crash reports have been used to advance motor vehicle safety research, though their value is limited by their focus on the crash event rather than outcomes of the crash.

Objective

To develop and evaluate the effect of enhanced recruitment methods, including a monetary incentive, on response rates of drivers identified on police reports in a national MVC surveillance system.

Methods

The National Automotive Sampling System-General Estimates System (NASS-GES) was used to identify passenger vehicle crashes between 1 July and 30 October 2012 involving drivers ≥16 years old with at least one child occupant ≤17 years old. We collected data from the driver via self-administered hardcopy or interviewer-administered telephone surveys. Within each survey mode, half the drivers were randomly assigned to receive a small monetary incentive. Response rates were calculated overall, and by mode of survey administration and incentive condition.

Results

495 drivers were eligible, and 127 completed the survey, yielding an overall response rate of 25.7% (95% CI 21.8% to 29.5%). The response rate across the two modes was higher for those who received an incentive than for those who did not (35.6% vs 15.7%, p<0.01). The highest response rate (45.9%) was for drivers allocated to the telephone survey who received an incentive.

Conclusions

The NASS-GES provides a surveillance system from which cases of interest can be identified and supplemental data collected via surveys of drivers identified on police reports. We adapted procedures commonly used in public health surveillance systems, including monetary incentives and branded recruitment materials, to improve driver response rates.
Entropic skill assessment of unmanned aerial systems (UAS) operators
Authors: Schnell T. , Engler J.
Published: May 2014

Large-scale distributed training exercises involve many trainees at various stages of their training maturity and at various levels of skill. Problems arise in large-scale exercises when less mature or lower-skilled trainees are exposed to training scenarios that are too advanced or too complex for their level of training maturity. These trainees are more likely to fail the mission they are given in the training scenario, thus reducing the benefits of training, leading to frustration in the trainee or even disrupting the training exercise. We present a methodology for automated skill assessment using entropy measures that form the core of a battery of automated assessment algorithms. As illustrated in a case study, in which subjects performed a reconnaissance task in a simulated unmanned aerial system environment, this methodology achieves high accuracy levels of skill assessment and has the added benefit of computational simplicity, allowing for real-time skill assessment of trainees.
The AEgIS experiment at CERN for the measurement of antihydrogen gravity acceleration
Authors: Scampoli Paola , Storey James
Published: May 2014

The Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy (AEgIS) experiment is conducted by an international collaboration based at CERN whose aim is to perform the first direct measurement of the gravitational acceleration of antihydrogen in the local field of the Earth, with Δg/g = 1% precision as a first achievement. The idea is to produce cold (100 mK) antihydrogen [Formula: see text] through a pulsed charge exchange reaction by overlapping clouds of antiprotons, from the Antiproton Decelerator (AD) and positronium atoms inside a Penning trap. The antihydrogen has to be produced in an excited Rydberg state to be subsequently accelerated to form a beam. The deflection of the antihydrogen beam can then be measured by using a moiré deflectometer coupled to a position sensitive detector to register the impact point of the anti-atoms through the vertex reconstruction of their annihilation products. After being approved in late 2008, AEgIS started taking data in a commissioning phase in 2012. This paper presents an outline of the experiment with a brief overview of its physics motivation and of the state-of-the-art of the g measurement on antimatter. Particular attention is given to the current status of the emulsion-based position detector needed to measure the [Formula: see text] sag in AEgIS.
Updated limits on extra dimensions through torsion and LHC data
Authors: Castillo-Felisola Oscar , Corral Cristobal , Schmidt Iván , Zerwekh Alfonso R.
Published: May 2014

It is well known that the inclusion of torsion in the gravitational formalism, leads to four-fermion interactions. Although the coupling constant of this interaction is strongly suppressed in four dimensions, its value is enhanced in models with n extra dimensions. In this context, we reinterpret the recent limits established by LHC experiments to four-fermion contact interactions, to set bounds on the size of the extra dimensions. For n = 2, the limits are comparable to those in the literature, while for n ≥ 3, the volume of the extra dimensions is strongly constrained.
Radioisotopes for medical imaging
Authors: Pimlott Sally L.
Published: May 2014

Radioisotopes are crucial in medical imaging for the diagnosis and monitoring of disease. The current status of radioisotope production is outlined and examples of their use are provided.
Solitary waves in an inhomogeneous chain of α-helical proteins
Authors: Mvogo Alain , Ben-Bolie G. H. , Kofané T. C.
Published: May 2014

The dynamics of Davydov's model of α-helical proteins is considered by including the influence of inhomogeneities in the monomer units. Using the D2 ansatz for the exciton–phonon quantum state, the model Hamiltonian is transformed into a pair of classical lattice equations, which is further reduced in the continuum limit to a sole perturbed nonlinear Schrödinger (NLS) equation. The results of the perturbation theory of this equation show that the inhomogeneities in the localized form do not affect the velocity and amplitude of the solitary waves during propagation. We employ also the sine–cosine functions method to construct the exact solitary wave solutions in the presence of a variety of nonlinear inhomogeneities such as biquadratic, exponential and periodic inhomogeneities and it reveals that the coherent energy transport in the α-helical proteins is very much influenced by these nonlinear inhomogeneities.
Collaborative Filtering beyond the User-Item Matrix
Authors: Shi Yue , Larson Martha , Hanjalic Alan
Published: May 2014

Over the past two decades, a large amount of research effort has been devoted to developing algorithms that generate recommendations. The resulting research progress has established the importance of the user-item (U-I) matrix, which encodes the individual preferences of users for items in a collection, for recommender systems. The U-I matrix provides the basis for collaborative filtering (CF) techniques, the dominant framework for recommender systems. Currently, new recommendation scenarios are emerging that offer promising new information that goes beyond the U-I matrix. This information can be divided into two categories related to its source: rich side information concerning users and items, and interaction information associated with the interplay of users and items. In this survey, we summarize and analyze recommendation scenarios involving information sources and the CF algorithms that have been recently developed to address them. We provide a comprehensive introduction to a large body of research, more than 200 key references, with the aim of supporting the further development of recommender systems exploiting information beyond the U-I matrix. On the basis of this material, we identify and discuss what we see as the central challenges lying ahead for recommender system technology, both in terms of extensions of existing techniques as well as of the integration of techniques and technologies drawn from other research areas.
A performance evaluation tool for hybrid and dynamic distributed systems
Authors: Silva Freitas Allan Edgard , de Araújo Macêdo Raimundo José
Published: May 2014

Distributed systems are usually modeled by a set of distributed processes spread over a number of networked computers. Such processes communicate and synchronize themselves by message passing through communication channels. Processes and communication channels can be characterized by synchronous or asynchronous timeliness behavior, according to the characteristics of underlying systems (operating system and communication sub-system). Unlike conventional distributed systems, the timeliness characteristics of dynamic and hybrid distributed systems may vary over time, according to the availability of resources and occurrence of failures. Such systems are becoming common today because of the increasing diversity and heterogeneity of computer networks and associated devices. Due to their high complexity, these systems are difficult to test or verify. In this paper, we introduce a novel simulation tool for such environments, where distinct fault models and timeliness properties can be dynamically assigned to processes and communication channels. Such a tool is meant not only for protocol evaluation but also for prototyping, allowing code reuse in real applications.
Embryo number and periconceptional undernutrition in the sheep have differential effects on adrenal epigenotype, growth, and development
Authors: Williams-Wyss Olivia , Zhang Song , MacLaughlin Severence M. , Kleemann David , Walker Simon K. , Suter Catherine M. , Cropley Jennifer E. , Morrison Janna L. , Roberts Claire T. , Caroline McMillen I.
Published: May 2014

Exposure to poor maternal nutrition around the time of conception results in an early prepartum activation of the fetal pituitary-adrenal axis and in increased adrenal growth and stress response after birth associated with epigenetic changes in a differentially methylated region (DMR) of adrenal IGF2/H19. We have determined the effects of maternal undernutrition during the periconceptional period (PCUN: 70% of control intake from 60 days before until 6 days after conception) and early preimplantation period (PIUN: 70% of control intake for 6 days after conception) on fetal plasma ACTH and cortisol concentrations and fetal adrenal ACTHR, StAR, 3βHSD, CYP11B, CYP17, TGFβ1, IGF1, IGF1R, IGF2, and IGF2R mRNA expression and the methylation level of sites within the DMRs of IGF2/H19 and IGF2R in the adrenal of twin and singleton fetuses at 136–138 days gestation. Being a twin resulted in a delayed prepartum increase in fetal ACTH and in a lower cortisol response to CRH in the control but not PCUN and PIUN groups. PCUN, but not PIUN, resulted in an increase in adrenal weight and CYP17 expression in singletons, a decrease in adrenal IGF2 expression in singletons, and an increase in adrenal IGF2R expression in both twins and singletons. IGF2/H19 and IGF2R DMR methylation levels and ACTHR expression were lower in the twin adrenal. Thus, exposure of the oocyte and embryo to maternal undernutrition or to the environment of a twin pregnancy have differential effects on epigenetic and other factors that regulate fetal adrenal growth and IGF2 and IGF2R expression.
Finite-Difference Simulation of Elastic Wave with Separation in Pure P- and S-Modes
Authors: Chen Ke-Yang
Published: May 2014

Elastic wave equation simulation offers a way to study the wave propagation when creating seismic data. We implement an equivalent dual elastic wave separation equation to simulate the velocity, pressure, divergence, and curl fields in pure P- and S-modes, and apply it in full elastic wave numerical simulation. We give the complete derivations of explicit high-order staggered-grid finite-difference operators, stability condition, dispersion relation, and perfectly matched layer (PML) absorbing boundary condition, and present the resulting discretized formulas for the proposed elastic wave equation. The final numerical results of pure P- and S-modes are completely separated. Storage and computing time requirements are strongly reduced compared to the previous works. Numerical testing is used further to demonstrate the performance of the presented method.
Analyzing Thermal Module Developments and Trends in High-Power LED
Authors: Wang Jung-Chang
Published: May 2014

The solid-state light emitting diode (SSLED) has been verified as consumer-electronic products and attracts attention to indoor and outdoor lighting lamp, which has a great benefit in saving energy and environmental protection. However, LED junction temperature will influence the luminous efficiency, spectral color, life cycle, and stability. This study utilizes thermal performance experiments with the illumination-analysis method and window program (vapour chamber thermal module, VCTM V1.0) to investigate and analyze the high-power LED (Hi-LED) lighting thermal module, in order to achieve the best solution of the fin parameters under the natural convection. The computing core of the VCTM program employs the theoretical thermal resistance analytical approach with iterative convergence stated in this study to obtain a numerical solution. Results showed that the best geometry of thermal module is 4.4 mm fin thickness, 9.4 mm fin pitch, and 37 mm fin height with the LED junction temperature of 58.8°C. And the experimental thermal resistances are in good agreement with the theoretical thermal resistances; calculating error between measured data and simulation results is no more than ±7%. Thus, the Hi-LED illumination lamp has high life cycle and reliability.
Experimental and Numerical Study of Stagnant Zones in Pebble Bed
Authors: Jia Xinlong , Yang Xingtuan , Gui Nan , Li Yu , Tu Jiyuan , Jiang Shengyao
Published: May 2014

The experimental method (side area method) and DEM simulation have been carried out to analyse the stagnant zone in the quasi-two-dimensional silos. The side area method is a phenomenological method by means of investigating the interface features of different areas composed of different coloured pebbles. Two methods have been discussed to define the stagnant zone. In particular, the area of the stagnant zone has been calculated with the mean-streamline method, and the tracking time of different marking pebbles has been investigated with the stagnant time method to explore the kinematics characteristics of the pebbles. The stagnant zone is crucial for the safety of the pebble-bed reactor, and the practical reactor core must avoid the existence of the stagnant zone. Furthermore, this paper also analyses the effects of bed configuration (the bed height, the base angle, and the friction coefficient) on stagnant zone with the two methods mentioned above. In detail, the bed height shows little impact on the stagnant zones when the bed height exceeds a certain limit, while the base angle has negative prominent correlation with the stagnant zone. The friction coefficient effect seems complicated and presents the great nonlinearity, which deserves to be deeply investigated.
Framework for a Cloud-Based Multimedia Surveillance System
Authors: Hossain M. Anwar
Published: May 2014

The new generation of multimedia surveillance systems integrates a large number of heterogeneous sensors to collect, process, and analyze multimedia data for identifying events of potential security threats. Some of the major concerns facing these systems are scalability, ubiquitous access to sensory data, event processing overhead, and massive storage requirements—all of which demand novel scalable approach. Cloud computing can provide a powerful and scalable infrastructure for large-scale storage, processing, and dissemination of sensor data. Furthermore, the integration of sensor technology and cloud computing offers new possibilities for efficient development and deployment of sensor-based systems. This paper proposes a framework for a cloud-based multimedia surveillance system and highlights several research and technical issues. A prototype surveillance system is also designed and analyzed in the context of the proposed surveillance framework. The paper finally reports that cloud-based multimedia surveillance system can effectively support the processing overload, storage requirements, ubiquitous access, security, and privacy in large-scale surveillance settings.
A Simple and Inexpensive Stereotactic Guidance Frame for MRI-Guided Brain Biopsy in Canines
Authors: Squires Alexander D. , Gao Yabiao , Taylor Sean F. , Kent Marc , Tse Zion Tsz Ho
Published: May 2014

A magnetic resonance imaging (MRI) guided stereotactic system was developed to provide veterinarians a method to accomplish minimally invasive stereotactic brain biopsies and procedures involving the cerebrum in canines. While MR-guided procedures are prevalent for humans, they are less common in animal practices. The system was designed to minimize fabrication costs in an effort to make such procedures more accessible in the veterinary field. A frame constrained the head without the need for punctures and supported registration and guidance attachments. Location data for registration and relevant structures were selected by the clinician, and a reverse kinematic analysis program generated the settings of the stereotactic arch to guide a needle to the desired location. Phantom experiments and three cadaver trials showed an average targeting error of <3 mm using the system.
A Critical Heat Generation for Safe Nuclear Fuels after a LOCA
Authors: Kim Jae-Yong , Kim Dong-Bock , Cho Hee-Jeong , Kwon Soon-Bum , Kwon Young-Doo
Published: May 2014

This study applies a thermo-elasto-plastic-creep finite element procedure to the analysis of an accidental behavior of nuclear fuel as well as normal behavior. The result will be used as basic data for the robust design of nuclear power plant and fuels. We extended the range of mechanical strain from small or medium to large adopting the Hencky logarithmic strain measure in addition to the Green-Lagrange strain and Almansi strain measures, for the possible large strain situation in accidental environments. We found that there is a critical heat generation after LOCA without ECCS (event category 5), under which the cladding of fuel sustains the internal pressure and temperature for the time being for the rescue of the power plant. With the heat generation above the critical value caused by malfunctioning of the control rods, the stiffness of cladding becomes zero due to the softening by high temperature. The weak position of cladding along the length continuously bulges radially to burst and to discharge radioactive substances. This kind of cases should be avoid by any means.
Finding Inhibitors of Mutant Superoxide Dismutase‐1 for Amyotrophic Lateral Sclerosis Therapy from Traditional Chinese Medicine
Authors: Huang Hung-Jin , Chang Tung-Ti , Chen Hsin-Yi , Chen Calvin Yu-Chian
Published: May 2014

Superoxide dismutase type 1 (SOD1) mutations cause protein aggregation and decrease protein stability, which are linked to amyotrophic lateral sclerosis (ALS) disease. This research utilizes the world’s largest traditional Chinese medicine (TCM) database to search novel inhibitors of mutant SOD1, and molecular dynamics (MD) simulations were used to analyze the stability of protein that interacted with docked ligands. Docking results show that hesperidin and 2,3,5,4′‐tetrahydroxystilbene‐2‐O‐β‐D‐glucoside (THSG) have high affinity to mutant SOD1 and then dopamine. For MD simulation analysis, hesperidin and THSG displayed similar value of RMSD with dopamine, and the migration analysis reveals stable fluctuation at the end of MD simulation time. Interestingly, distance between the protein and ligand has distinct difference, and hesperidin changes the position from initial binding site to the other place. In flexibility of residues analysis, the secondary structure among all complexes does not change, indicating that the structure are not affect ligand binding. The binding poses of hesperidin and THSG are similar to dopamine after molecular simulation. Our result indicated that hesperidin and THSG might be potential lead compound to design inhibitors of mutant SOD1 for ALS therapy.
Synthesis and Physicochemical Characterization of Mesoporous SiO2 Nanoparticles
Authors: Das Dharani , Yang Yong , O’Brien Julie S. , Breznan Dalibor , Nimesh Surendra , Bernatchez Stéphane , Hill Myriam , Sayari Abdelhamid , Vincent Renaud , Kumarathasan Prem
Published: May 2014

There exists a knowledge gap in understanding potential toxicity of mesoporous silica nanoparticles. A critical step in assessing toxicity of these particles is to have a wide size range with different chemistries and physicochemical properties. There are several challenges when synthesizing mesoporous silica nanoparticles over a wide range of sizes including (1) nonuniform synthesis protocols using the same starting materials, (2) the low material yield in a single batch synthesis (especially for particles below 60–70 nm), and (3) morphological instability during surfactant removal process and surface modifications. In this study, we synthesized a library of mesoporous silica nanoparticles with approximate particle sizes of 25, 70, 100, 170, and 600 nm. Surfaces of the silica nanoparticles were modified with hydrophilic‐CH2–(CH2)2–COOH and relatively hydrophobic‐CH2–(CH2)10–COOH functional groups. All silica nanoparticles were analysed for morphology, surface functionality, surface area/pore volume, surface organic content, and dispersion characteristics in liquid media. Our analysis revealed the synthesis of a spectrum of monodisperse bare and surface modified mesoporous silica nanoparticles with a narrow particle size distribution and devoid of cocontaminants critical for toxicity studies. Complete physicochemical characterization of these synthetic mesoporous silica nanoparticles will permit systematic toxicology studies for investigation of structure‐activity relationships.
Cytocompatibility and Antibacterial Properties of Capping Materials
Authors: Poggio Claudio , Arciola Carla Renata , Beltrami Riccardo , Monaco Annachiara , Dagna Alberto , Lombardini Marco , Visai Livia
Published: May 2014

The aim of this study was to evaluate and compare the antimicrobial activity and cytocompatibility of six different pulp-capping materials: Dycal (Dentsply), Calcicur (Voco), Calcimol LC (Voco), TheraCal LC (Bisco), MTA Angelus (Angelus), and Biodentine (Septodont). To evaluate antimicrobial activity, materials were challengedin vitrowithStreptococcus mutans,Streptococcus salivarius, andStreptococcus sanguisin the agar disc diffusion test. Cytocompatibility of the assayed materials towards rat MDPC-23 cells was evaluated at different times by both MTT and apoptosis assays. Results significantly differed among the different materials tested. Both bacterial growth inhibition halos and cytocompatibility performances were significantly different among materials with different composition. MTA-based products showed lower cytotoxicity and valuable antibacterial activity, different from calcium hydroxide-based materials, which exhibited not only higher antibacterial activity but also higher cytotoxicity.