bluuebunny/crossref_metadata_2025 huggingface dataset:
Metallurgical Investigations on Hyperplasticity in Dual Phase Steel Sheets
Authors: Samei Javad , Green Daniel E. , Golovashchenko Sergey
Published: April 2014

Several researchers have reported that dual phase steel sheets exhibit hyperplasticity, that is, a significant formability improvement under certain high strain rate forming conditions. Hyperplastic behavior of dual phase steels formed using an electrohydraulic forming (EHF) process was previously investigated by the authors at both macro- (Golovashchenko et al., 2013, “Formability of Dual Phase Steels in Electrohydraulic Forming,” J. Mater. Process. Technol., 213, pp. 1191–1212) and microscales (Samei et al., 2013, “Quantitative Microstructural Analysis of Formability Enhancement in Dual Phase Steels Subject to Electrohydraulic Forming,” J. Mater. Eng. Perform., 22(7), pp. 2080–2088). A relative deformation improvement of approximately 20% in ferrite grains and 100% in martensite islands was reported in the EHF specimens compared to specimens formed under quasi-static conditions. In this paper, the remarkable deformation improvements of the constituents are discussed in terms of metallurgical mechanisms of deformation. The nucleation and multiplication of dislocations in ferrite and deformation twinning in martensite were found to be the principal mechanisms responsible for the significant improvements of deformation in EHF. In addition, these mechanisms enhance the plastic compatibility between the two phases which reduces the risk of decohesion and delays the onset of fracture in EHF specimens.
Retrieving Causally Related Functions From Natural-Language Text for Biomimetic Design
Authors: Cheong Hyunmin , Shu L. H.
Published: April 2014

Identifying biological analogies is a significant challenge in biomimetic (biologically inspired) design. This paper builds on our previous work on finding biological phenomena in natural-language text. Specifically, a rule-based computational technique is used to identify biological analogies that contain causal relations. Causally related functions describe how one function is enabled by another function, and support the transfer of functional structure from analogies to design solutions. The causal-relation retrieval method uses patterns of syntactic information that represent causally related functions in individual sentences, and scored F-measures of 0.73–0.85. In a user study, novice designers found that of the total search matches, proportionally more of the matches obtained with the causal-relation retrieval method were relevant to design problems than those obtained with a single verb-keyword search. In addition, matches obtained with the causal-relation retrieval method increased the likelihood of using functional association to develop design concepts. Finally, the causal-relation retrieval method enables automatic extraction of biological analogies at the sentence level from a large amount of natural-language sources, which could support other approaches to biologically inspired design that require the identification of interesting biological phenomena.
Predicting Change Propagation in Complex Design Workflows
Authors: Wynn David C. , Caldwell Nicholas H. M. , John Clarkson P.
Published: April 2014

A simulation model to help manage change propagation through design workflows is introduced. The model predicts resource requirements and schedule risk of a change process, accounting for concurrency, multiple sources of change, and iterations during redesign. Visualizations provide insight to answer common management questions. The approach is illustrated using an aircraft design workflow from Airbus and a more complex turbine disk design workflow from Rolls–Royce.
Friction Compensation of Geared Actuators With High Presliding Stiffness
Authors: Sin Aung Myo Thant , Kikuuwe Ryo , Yamamoto Motoji
Published: April 2014

Most of existing friction compensation techniques are based on friction models that uses the velocity as its input. These methods are difficult to apply to inexpensive encoder-based actuator systems that do not exhibit sufficiently large presliding displacement. This paper presents a new method of friction compensation that can be applied to geared actuators with high presliding stiffness. The compensator consists of three components that compensate: (a) static friction, (b) rate-dependent kinetic friction, and (c) dynamic friction involving presliding viscoelasticity. The first component employs dither-like torque command, and the other two are based on friction models involving precalibrated parameters. The proposed method is validated through experiments employing a harmonic drive transmission. In particular, it is suggested that the dither-like static friction compensation and the viscosity in the presliding model significantly improve the performance of the compensator.
Global Identification of Joint Drive Gains and Dynamic Parameters of Robots
Authors: Gautier Maxime , Briot Sébastien
Published: April 2014

Off-line robot dynamic identification methods are based on the use of the inverse dynamic identification model (IDIM), which calculates the joint forces/torques that are linear in relation to the dynamic parameters, and on the use of linear least squares technique to calculate the parameters (IDIM-LS technique). The joint forces/torques are calculated as the product of the known control signal (the input reference of the motor current loop) by the joint drive gains. Then it is essential to get accurate values of joint drive gains to get accurate estimation of the motor torques and accurate identification of dynamic parameters. The previous works proposed to identify the gain of one joint at a time using data of each joint separately. This is a sequential procedure which accumulates errors from step to step. To overcome this drawback, this paper proposes a global identification of the drive gains of all joints and the dynamic parameters of all links. They are calculated altogether in a single step using all the data of all joints at the same time. The method is based on the total least squares solution of an overdetermined linear system obtained with the inverse dynamic model calculated with available input reference of the motor current loop and joint position sampled data while the robot is tracking some reference trajectories without load on the robot and some trajectories with a known payload fixed on the robot. The method is experimentally validated on an industrial Stäubli TX-40 robot.
An Improved Cumulative Damage Criterion for Preloaded Threaded Fasteners
Authors: Nassar Sayed A. , Ali Rania A.
Published: April 2014

An improved cumulative damage criterion is proposed for preloaded threaded fasteners. The proposed criterion takes into account the effect of bolt mean stress, damage history, and the loading sequence. Baseline mean stress-adjusted fatigue curves are first established for two sizes of A286 steel bolts with round socket heads. Fatigue curves are subsequently lowered due to calculable partial damage that each step of a loading spectrum. Theoretical results are experimentally validated using a three-stage loading spectrum that is applied in a low-to-high (L–H) or high-to-low (H–L) loading sequence.
Fuzzy Approximation by a Novel Levenberg–Marquardt Method for Two-Degree-of-Freedom Hypersonic Flutter Model
Authors: Wang Y. H. , Zhu L. , Wu Q. X. , Jiang C. S.
Published: April 2014

The two-degree-of-freedom (2DOF) hypersonic flutter dynamical system has strong aeroelastic nonlinearities, and it is very difficult to obtain a more precise mathematical model. By considering varying learning rate and σ-modification factor, a novel Levenberg– Marquardt (L–M) method is proposed, based on which, an online fuzzy approximation scheme for 2DOF hypersonic flutter model is established without any human knowledge. Compared with the standard L–M method, the proposed method can obtain faster converge speed and avoid parameter drift. Numerical simulations approve the advantages of the proposed scheme.
Physics and the revised Medical College Admission Test
Authors: Hilborn Robert C.
Published: April 2014

Physics has played an important role in the preparation of future physicians and other health professionals for more than 100 years. Almost all pre-health students take a year of college-level physics as part of their preparation for medical, dental, and pharmacy school. In particular, the widely-used Medical College Admission Test (MCAT) contains a significant number of questions that require physics knowledge and skills. This paper describes the changes in the MCAT to be implemented in 2015, the role of physics in the revised MCAT, and implications for introductory physics courses for the life sciences.
Biology's built-in Faraday cages
Authors: Klee Maurice M.
Published: April 2014

Biological fluids are water-based, ionic conductors. As such, they have both high relative dielectric constants and substantial conductivities, meaning they are lossy dielectrics. These fluids contain charged molecules (free charges), whose movements play roles in essentially all cellular processes from metabolism to communication with other cells. Using the problem of a point source in air above a biological fluid of semi-infinite extent, the bound charges in the fluid are shown to perform the function of a fast-acting Faraday cage, which protects the interior of the fluid from external electric fields. Free charges replace bound charges in accordance with the fluid's relaxation time, thereby providing a smooth transition between the initial protection provided by the bound charges and the steady state protection provided by the free charges. The electric fields within the biological fluid are thus small for all times just as they would be inside a classical Faraday cage.
Dielectric resonating microspheres for biosensing: An optical approach to a biological problem
Authors: Carrier Jean-Raphaël , Boissinot Maurice , Nì. Allen Claudine
Published: April 2014

Detecting and identifying biomolecules or microorganisms in aqueous solutions are often a complex task requiring precious amounts of time. Decreasing this time while reducing costs and minimizing complexity is crucial for several applications in the life sciences and other fields and is the subject of extensive work by biologists and biomedical engineers around the world. Optical sensors, more specifically dielectric microspheres, have been proposed as suitable sensors for viruses, bacteria, and other biological analytes. This paper reviews initial key publications as well as the latest progress regarding such microspheres and their potential use as biological sensors. We cover recent work on fluorescent microspheres and their integration in microfluidic devices, while addressing the limitations and practical requirements of such biodiagnostics. Our aim in this paper is to appeal to both biologists and physicists, even if new to this field. We conclude by briefly suggesting ways of integrating dielectric microspheres and biosensing into college and university courses in both physics and in biology.
NEXUS/Physics: An interdisciplinary repurposing of physics for biologists
Authors: Redish E. F. , Bauer C. , Carleton K. L. , Cooke T. J. , Cooper M. , Crouch C. H. , Dreyfus B. W. , Geller B. D. , Giannini J. , Gouvea J. S. , Klymkowsky M. W. , Losert W. , Moore K. , Presson J. , Sawtelle V. , Thompson K. V. , Turpen C. , Zia R. K. P.
Published: April 2014

In response to increasing calls for the reform of the undergraduate science curriculum for life science majors and pre-medical students (Bio2010, Scientific Foundations for Future Physicians, Vision & Change), an interdisciplinary team has created NEXUS/Physics: a repurposing of an introductory physics curriculum for the life sciences. The curriculum interacts strongly and supportively with introductory biology and chemistry courses taken by life-science students, with the goal of helping students build general, multi-discipline scientific competencies. NEXUS/Physics stresses interdisciplinary examples and the content differs markedly from traditional introductory physics to facilitate this: it extends the discussion of energy to include interatomic potentials and chemical reactions, the discussion of thermodynamics to include enthalpy and Gibbs free energy and includes a serious discussion of random vs coherent motion including diffusion. The development of instructional materials is coordinated with careful education research. Both the new content and the results of the research are described in a series of papers for which this paper serves as an overview and context.
Bridging physics and biology teaching through modeling
Authors: Hoskinson Anne-Marie , Couch Brian A. , Zwickl Benjamin M. , Hinko Kathleen A. , Caballero Marcos D.
Published: April 2014

As the frontiers of biology become increasingly interdisciplinary, the physics education community has engaged in ongoing efforts to make physics classes more relevant to life science majors. These efforts are complicated by the many apparent differences between these fields, including the types of systems that each studies, the behavior of those systems, the kinds of measurements that each makes, and the role of mathematics in each field. Nonetheless, physics and biology are both sciences that rely on observations and measurements to construct models of the natural world. In this article, we propose that efforts to bridge the teaching of these two disciplines must emphasize shared scientific practices, particularly scientific modeling. We define modeling using language common to both disciplines and highlight how an understanding of the modeling process can help reconcile apparent differences between the teaching of physics and biology. We elaborate on how models can be used for explanatory, predictive, and functional purposes and present common models from each discipline demonstrating key modeling principles. By framing interdisciplinary teaching in the context of modeling, we aim to bridge physics and biology teaching and to equip students with modeling competencies applicable in any scientific discipline.
Home office worker performance and perception as affected by residential audible distractions through various wall constructions
Authors: Wagner Alicia J.
Published: April 2014

This research examines the effects that residential audible distractions have on task performance and subjective perception of home office workers when transmitted across various residential wall constructions. Subjects performed math, verbal, and typing tasks while exposed to 16-h-long sound signals. These signals were generated using four audio filters simulating residential wall constructions providing varying degrees of acoustic attenuation ranging from field sound transmission classes of 36–58. The audio filters were applied to four types of audible distractions: (1) pop music, (2) television, (3) conversation, and (4) a potpourri of kitchen, pet, and children’s noises. A questionnaire was also administered to determine participants’ perception of loudness, variation in time, distraction, and annoyance. Statistical analyses indicate that none of the wall constructions or audible distractions significantly affected task performance. However, subjective perception does appear to be related to both factors. The relationship between task performance and subjective perception was also examined, yielding significant results between typing and subjective perception.
Bistatic specular reflection by a proud cone: Experiments and interpretation.
Authors: La Follett Jon , Marston Philip L.
Published: April 2014

For sufficiently small grazing angles of illumination, specular backscattering of high frequency sound by a proud cone having a vertical symmetry axis is not observed from geometric considerations. Observations from scaled tank experiments suggest, however, that specular scattering from a conical target in this configuration can be observed at shallow grazing angles bistatically. Bright features in the scattering corresponded to sound that had interacted with the flat boundary and the cone and to direct acoustic reflections from the cone. Feature locations were in agreement with a geometric analysis of bistatic reflection [P. Marston, J. Acoust. Soc. Am. 124, 2584 (2008)] modified so as to allow for images caused by the flat surface. Data were obtained by suspending the apex of a small solid aluminum cone through the air-water interface of a tank. The cone was illuminated from below at grazing incidence and the free surface simulated the ocean floor. Bistatic measurements were obtained by scanning a hydrophone along a line parallel to the interface at varied depths. Data were also obtained from a truncated cone. [Research supported by ONR.]
The Effect of Signal-Noise Levels on Pitch Discrimination in Masking
Authors: Harris J. Donald
Published: April 2014

Preliminary work shows that a thermal noise which comes within a few decibels of masking a pure tone, does not appreciably change the relative characteristics of the pure tone differential pitch threshold, throughout that part of the auditory sensation area studied. The absolute size of all thresholds is, however, increased. The present study, on several score individuals, describes the course of pitch discrimination in masking, as a function of signal-noise level. With the pure tone set at in-masking threshold with a thermal noise of a particular intensity level, the differential threshold was studied as the mask was decreased until its effect was negligible. A wide range of thermal noise levels was used. Surprisingly good discrimination is present when the pure tone is within only 5 db of being masked altogether. The mask exerts a negatively accelerated effect until the pure tone is about 15 db above its in-noise threshold. A preliminary integration of pitch along one frequency continuum reveals that for tones within 5 db of being masked, far fewer perceptible pitch gradations are available than the approximately 2000 calculated by Fletcher for pitch in quiet. The implications of these results for the physiology of the basilar membrane are discussed.
Absorption of Sound by Patches of Absorbent Material
Authors: Cook Richard K.
Published: April 2014

A circular patch, or a long strip, of sound absorbent material is on the surface of an infinite reflecting plane. An integral equation technique is used to determine the absorption of plane waves. The basis of the technique is representation of the scattered waves by a superposition of plane waves for strips, and cylindrical waves for circular patches. Calculations can be readily made for absorbers which satisfy a linear homogeneous boundary condition in sound pressure and its gradient (normal impedance assumption), and for piston-like absorbers.
The Fun Integration Theory: Toward Sustaining Children and Adolescents Sport Participation
Authors: Visek Amanda J. , Achrati Sara M. , Mannix Heather M. , McDonnell Karen , Harris Brandonn S. , DiPietro Loretta
Published: April 2014

Background:

Children cite “fun” as the primary reason for participation in organized sport and its absence as the number-one reason for youth sport attrition. Therefore, the purpose of this study was to develop a theoretical framework of fun using a novel mixed-method assessment of participants in sport (FUN MAPS) via concept mapping.

Methods:

Youth soccer players (n = 142), coaches (n = 37), and parents (n = 57) were stratified by age, sex, and competition level and contributed their ideas through (a) qualitative brainstorming, identifying all of the things that make playing sports fun for players; (b) sorting of ideas; and (c) rating each idea on its importance, frequency, and feasibility.

Results:

The FUN MAPS identify the 4 fundamental tenets of fun in youth sport within 11 fun-dimensions composed of 81 specific fun-determinants, while also establishing the youth sport ethos.

Conclusion:

The FUN MAPS provide pictorial evidence-based blueprints for the fun integration theory (FIT), which is a multitheoretical, multidimensional, and stakeholder derived framework that can be used to maximize fun for children and adolescents to promote and sustain an active and healthy lifestyle through sport.
Do Students Know the Physical Activity Recommendations for Health Promotion?
Authors: Marques Adilson , Martins João , Sarmento Hugo , Rocha Leonardo , Costa Francisco Carreiro da
Published: April 2014

Background:

Knowledge is required for people to make health decisions. It can be conjectured that knowledge of physical activity recommended levels can be a step to behavior change. This study examined the knowledge of physical activity guidelines of adolescents who were completing the secondary school.

Methods:

A survey was conducted with 2718 students (1613 girls), aged 16 to 18 years (Mean = 17.2 ± 0.2 years). Gender and age were self-reported and socioeconomic status was calculated based on parental occupation. Students were asked about frequency, duration, and intensity of physical activity to achieve the recommended level. Chi-square was applied to the results.

Results:

16.2% reported that physical activity should be practiced daily. For the duration component of the recommendation, 43.5% identified correctly that the minimum recommended is 60 min/day. The intensity component was correctly answered by 62.7%. Considering all the components of the recommendation, only 3.6% of the students were able to identify correctly the physical activity recommendation, with no differences between genders or among socioeconomic status.

Conclusions:

These results highlight the need for an effective communication strategy for disseminating the message to ensure that young people are aware of, and understand the physical activity guidelines.
Effect of Physical Inactivity on Major Noncommunicable Diseases and Life Expectancy in Brazil
Authors: de Rezende Leandro Fornias Machado , Rabacow Fabiana Maluf , Viscondi Juliana Yukari Kodaira , Luiz Olinda do Carmo , Matsudo Victor Keihan Rodrigues , Lee I-Min
Published: April 2014

Background:

In Brazil, one-fifth of the population reports not doing any physical activity. This study aimed to assess the impact of physical inactivity on major noncommunicable diseases (NCDs), all-cause mortality and life expectancy in Brazil, by region and sociodemographic profile.

Methods:

We estimated the population attributable fraction (PAF) for physical inactivity associated with coronary heart disease, type 2 diabetes, breast cancer, colon cancer, and all-cause mortality. To calculate the PAF, we used the physical inactivity prevalence from the 2008 Brazilian Household Survey and relative risk data in the literature.

Results:

In Brazil, physical inactivity is attributable to 3% to 5% of all major NCDs and 5.31% of all-cause mortality, ranging from 5.82% in the southeastern region to 2.83% in the southern region. Eliminating physical inactivity would increase the life expectancy by an average of 0.31 years. This reduction would affect mainly individuals with ≥ 15 years of schooling, male, Asian, elderly, residing in an urban area and earning ≥ 2 times the national minimum wage.

Conclusions:

In Brazil, physical inactivity has a major impact on NCDs and mortality, principally in the southeastern and central-west regions. Public policies and interventions promoting physical activity will significantly improve the health of the population.
Single-Cell Genomics Reveals Hundreds of Coexisting Subpopulations in WildProchlorococcus
Authors: Kashtan Nadav , Roggensack Sara E. , Rodrigue Sébastien , Thompson Jessie W. , Biller Steven J. , Coe Allison , Ding Huiming , Marttinen Pekka , Malmstrom Rex R. , Stocker Roman , Follows Michael J. , Stepanauskas Ramunas , Chisholm Sallie W.
Published: April 2014

Cyanobacterial Diversity

What does it mean to be a global species? The marine cyanobacteriumProchlorococcusis ubiquitous and, arguably, the most abundant and productive of all living organisms. Although to our eyes the seas look uniform, to a bacterium the ocean's bulk is a plethora of microhabitats, and by large-scale single-cell genomic analysis of uncultured cells,Kashtanet al.(p.416; see the Perspective byBowler and Scanlan) reveal thatProchlorococcushas diversified to match. This “species” constitutes a mass of subpopulations—each with million-year ancestry—that vary seasonally in abundance. The subpopulations in turn have clades nested within that show covariation between sets of core alleles and variable gene content, indicating flexibility of responses to rapid environmental changes. Large sets of coexisting populations could be a general feature of other free-living bacterial species living in highly mixed habitats.
Mechanisms of reef coral resistance to future climate change
Authors: Palumbi Stephen R. , Barshis Daniel J. , Traylor-Knowles Nikki , Bay Rachael A.
Published: April 2014

Reef corals are highly sensitive to heat, yet populations resistant to climate change have recently been identified. To determine the mechanisms of temperature tolerance, we reciprocally transplanted corals between reef sites experiencing distinct temperature regimes and tested subsequent physiological and gene expression profiles. Local acclimatization and fixed effects, such as adaptation, contributed about equally to heat tolerance and are reflected in patterns of gene expression. In less than 2 years, acclimatization achieves the same heat tolerance that we would expect from strong natural selection over many generations for these long-lived organisms. Our results show both short-term acclimatory and longer-term adaptive acquisition of climate resistance. Adding these adaptive abilities to ecosystem models is likely to slow predictions of demise for coral reef ecosystems.
Genome Sequences of Eight Salmonella enterica subsp.
enterica
Serovars Isolated from a Single Dairy Farm
Authors: Haley Bradd J. , Luo Yan , Wang Charles , Pettengill James , Allard Marc , Brown Eric , Karns Jeffrey S. , Van Kessel Jo Ann
Published: April 2014

Here, we report draft genome sequences of 26 isolates of
Salmonella enterica
subsp.
enterica
, representing eight serotypes, which were isolated from cows in a Pennsylvania dairy herd, the farm on which they were reared, and the associated off-site heifer-raising facility over an 8-year sampling period.
Complete Genome Sequence of a Newcastle Disease Virus Isolate from an Outbreak in Northern India
Authors: Morla Sudhir , Kumar Tiwari Ashok , Joshi Vinay , Kumar Sachin
Published: April 2014

The complete genome sequence was determined for a Newcastle disease virus strain from vaccinated chicken farms in India during outbreaks in 2010. The genome is 15,192 nucleotides (nt) in length and is classified as genotype VII in class II. Compared to the available vaccine strains, the Indian strain contains a previously described 6-nt insertion in the untranslated region of the nucleoprotein gene.
Complete Genome Sequence of Phage-Like Plasmid pECOH89, Encoding CTX-M-15
Authors: Falgenhauer Linda , Yao Yancheng , Fritzenwanker Moritz , Schmiedel Judith , Imirzalioglu Can , Chakraborty Trinad
Published: April 2014

A nonconjugative and nontypable plasmid of a clinical
Escherichia coli
isolate expressing resistance to extended-spectrum cephalosporins (ESCs) was isolated and sequenced. The plasmid pECOH89 contains a CTX-M-15 resistance cassette and comprises 111,741 bp, with strong homology to bacteriophage-like plasmids and to the
Salmonella
-specific bacteriophage SSU5.
Norovirus GII.4 Detection in Environmental Samples from Patient Rooms during Nosocomial Outbreaks
Authors: Nenonen Nancy P. , Hannoun Charles , Svensson Lennart , Torén Kjell , Andersson Lars-Magnus , Westin Johan , Bergström Tomas
Published: April 2014

Norovirus (NoV) is an important cause of nosocomial gastroenteric outbreaks. This 5-month study was designed to characterize NoV contamination and airborne dispersal in patient rooms during hospital outbreaks. Air vents, overbed tables, washbasins, dust, and virus traps designed to collect charged particles from the air were swabbed to investigate the possibility of NoV contamination in patient rooms during outbreaks in seven wards and in an outbreak-free ward. Symptomatic inpatients were also sampled. Nucleic acid extracts of the samples were examined for NoV RNA using genogroup I (GI) and GII real-time reverse transcription-PCR (RT-PCR). The NoV strains were characterized by RT-PCR, sequencing, and phylogenetic analysis of the RNA-dependent RNA-polymerase-N/S capsid-coding region (1,040 nucleotides [nt]). Patient strains from two outbreaks in one ward were sequenced across the RNA-dependent-RNA-polymerase major capsid-coding region (2.5 kb), including the hypervariable P2 domain. In the outbreak wards, NoV GII was detected in 48 of 101 (47%) environmental swabs and 63 of 108 patients (58%); NoV genotype II.4 was sequenced from 18 environmental samples, dust (
n
= 8), virus traps (
n
= 4), surfaces (
n
= 6), and 56 patients. In contrast, NoV GII was detected in 2 (GII.4) of 28 (7%) environmental samples and in 2 (GII.6 and GII.4) of 17 patients in the outbreak-free ward. Sequence analyses revealed a high degree of similarity (>99.5%, 1,040 nt) between NoV GII.4 environmental and patient strains from a given ward at a given time. The strains clustered on 11 subbranches of the phylogenetic tree, with strong correlations to time and place. The high nucleotide similarity between the NoV GII.4 strains from patients and their hospital room environment provided molecular evidence of GII.4 dispersal in the air and dust; therefore, interventional cleaning studies are justified.
Mechanical Homogenization Increases Bacterial Homogeneity in Sputum
Authors: Stokell Joshua R. , Khan Ammad , Steck Todd R.
Published: April 2014

Sputum obtained from patients with cystic fibrosis (CF) is highly viscous and often heterogeneous in bacterial distribution. Adding dithiothreitol (DTT) is the standard method for liquefaction prior to processing sputum for molecular detection assays. To determine if DTT treatment homogenizes the bacterial distribution within sputum, we measured the difference in mean total bacterial abundance and abundance of
Burkholderia multivorans
between aliquots of DTT-treated sputum samples with and without a mechanical homogenization (MH) step using a high-speed dispersing element. Additionally, we measured the effect of MH on bacterial abundance. We found a significant difference between the mean bacterial abundances in aliquots that were subjected to only DTT treatment and those of the aliquots which included an MH step (all bacteria,
P
= 0.04;
B. multivorans
,
P
= 0.05). There was no significant effect of MH on bacterial abundance in sputum. Although our results are from a single CF patient, they indicate that mechanical homogenization increases the homogeneity of bacteria in sputum.
Outcome and reinfection afterStaphylococcus aureusbacteraemia in individuals with and without HIV-1 infection: a case–control study
Authors: Stammler Jaliff Bianca , Dahl-Knudsen Jenny , Petersen Andreas , Skov Robert , Benfield Thomas
Published: April 2014

Objectives

Individuals infected with HIV-1 are at an increased risk ofStaphylococcus aureusbacteraemia (SAB). The aim of this study was to investigate mortality rate and risk of reinfection associated with SAB in HIV-1-infected individuals compared to individuals without HIV-1 infection.

Setting

University hospital treating a third of the estimated 5000 individuals with HIV infection in Denmark.

Participants

HIV-1-infected (n=82) and sex-matched and age-matched uninfected (n=163) individuals with SAB in the time period 1 January 1995 to 31 December 2010.

Primary outcome measures

30-day and 365-day mortality rate ratio and relative risk of reinfection.

Results

Individuals with HIV had an increased risk of death at day 30 (OR 11.90 (95% CI 2.15 to 65.85)) compared to individuals without HIV. Other factors associated with mortality were age, a foreign device and Pitt score. HIV-related factors did not associate to mortality. During follow-up, there were 43 episodes of reinfection; in individuals with HIV infection at an incidence rate of 7.8 (95% CI 4.7 to 10.9)/100 person-years compared with 2.2 (95% CI 1.2 to 3.2)/100 person-years for individuals without HIV. In multivariate analysis, HIV status (OR 2.91 (95% CI 1.29 to 6.58) and injection drug use (OR 3.51 (95% CI 1.06 to 11.63) were independently associated with an increased risk of reinfection.

Conclusions

HIV-1 infection is associated with an increased risk of 30-day mortality after SAB and a very high rate of reinfection. Age, a foreign device and Pitt score predicted outcome. For patients infected with HIV, neither CD4 T-lymphocyte counts nor plasma HIV RNA levels were associated with 30-day outcome.

Trial registration number

The study was approved by the Danish Data Protection Agency (record no. 2007-41-1196).
Impact of age on 30-day postoperative outcome of surgery for ruptured and unruptured intracranial aneurysms
Authors: Alan Nima , Seicean Andreea , Seicean Sinziana , Selman Warren R , Bambakidis Nicholas C
Published: April 2014

Objective

To assess in a retrospective analysis of a prospectively collected database, the impact of increased age on 30-day postoperative outcomes of surgery for intracranial aneurysms (ICAs).

Methods

721 adult patients who underwent surgery for ICA were identified in the 2006–2012 American College of Surgeons’ National Surgical Quality Improvement Program. Baseline characteristics and 30-day outcomes were stratified by age: <50 years (n=221), 50–60 years (n=221), and >60 years (n=266). Patients <50 and 50–60 years old were propensity score-matched to those aged >60 years. Logistic regression was used to examine the relationship between increased age and surgical outcome.

Results

In unadjusted analyses, age <50 years was associated with fewer postoperative complications (OR=0.5, 95% CI 0.3 to 0.7) and lower mortality (OR=0.4, 95% CI 0.2 to 0.9) compared with those aged >60 years. Patients aged between 50 and 60 years were less likely to have complications (OR=0.6, 95% CI 0.4 to 0.8) in unadjusted analyses. Upon propensity score matching, covariate balance was achieved for all age strata. In adjusted analyses, patients <50 years (OR=0.4, 95% CI 0.2 to 0.7) and 50–60 years (OR=0.5, 95% CI 0.3 to 0.8) of age continued to have fewer complications than those aged >60.

Conclusions

Age >60 is independently associated with 30-day postoperative morbidity in patients undergoing surgery for ICA. The results of this study suggest age >60 should be considered an a priori risk factor in surgical management of ICA, regardless of associated comorbidities often associated with increased age.
The effect of primary care fellowship training on career satisfaction, happiness and perceived stress
Authors: Duffrin Christopher , Larsen Lars
Published: April 2014

Purpose

This study was designed to measure the impact of primary care fellowship training on the subsequent happiness, career satisfaction and perceived stress levels of fellowship-trained physicians as compared to a general population of Family Medicine physicians in North Carolina.

Methods

A written survey instrument was completed by fellowship graduates of the Brody School of Medicine (n=53) and general population of Family Medicine physicians in North Carolina (n=203) in 2011. The survey included general demographic and practice variables, and validated psychological scales on subjective happiness, satisfaction with life, and perceived stress.

Results

Fellowship graduates (n=50), and non-fellowship graduates (n=203), exhibited similar levels of satisfaction with life (fellows=27.36 SD 5.45, FM physicians=26.91, SD 5.99 on a 5–35 scale), statistically higher levels of perceived stress (fellows=5.92, SD 3.03, FM physicians=4.98, SD 2.70 on a 0–16 scale), and significantly higher levels of subjective happiness (fellows=5.61SD 83, FM physician=4.75 SD 1.00 on a 1–7 scale). Female fellow response was significantly higher on the Satisfaction with Life and Subjective Happiness Scores, and lower on the Perceived Stress Scale. Male fellowship graduates presented with a reverse relationship, with higher perceived stress and lower satisfaction with life and subjective happiness.

Conclusions

Fellowship training exhibited a positive psychological effect on the graduate respondents versus the general physician population. Scores on various well-being scales were higher than the general Family Medicine physician population as a whole, although stress levels were also higher. Female physicians seem to garner a much larger gain in satisfaction than male fellowship graduates, who score slightly worse than the general family medicine population on the satisfaction with life and Perceived Stress Scales.
The Commonwealth Veterinary Association – what does it do?
Authors: Reed Karen
Published: April 2014

Many UK vets may be aware that there is a Commonwealth Veterinary Association (CVA), but they may not be quite so sure about what it does. Karen Reed, the current CVA secretary, explains more
Origin and evolution of structure and nucleosynthesis for galaxies in the local group
Authors: Mathews G. J. , Snedden A. , Phillips L. A. , Suh I.-S. , Coughlin J. , Bhattacharya A. , Zhao X. , Lan N. Q.
Published: April 2014

The Milky Way is the product of a complex evolution of generations of mergers, collapse, star formation, supernova and collisional heating, radiative and collisional cooling, and ejected nucleosynthesis. Moreover, all of this occurs in the context of the cosmic expansion, the formation of cosmic filaments, dark matter halos, spiral density waves, and emerging dark energy. In this review we summarize observational evidence and discuss recent calculations concerning the formation, evolution nucleosynthesis in the galaxies of the Local Group (LG). In particular, we will briefly summarize observations and simulations for the dwarf galaxies and the two large spirals of the LG. We discuss how galactic halos form within the dark matter filaments that define a super-galactic plane. Gravitational interaction along this structure leads to streaming flows toward the two dominant galaxies in the cluster. These simulations and observations also suggest that a significant fraction of the Galactic halo formed as at large distances and then arrived later along these streaming flows. We also consider the insight provided by observations and simulations of nucleosynthesis both within the galactic halo and dwarf galaxies in the LG.
Review on loop integrals which need regularization but yield finite results
Authors: Weinzierl Stefan
Published: April 2014

In this pedagogical paper I will discuss one-loop integrals, where (i) different regions of the integration region lead to divergences and (ii) where these divergences cancel in the sum over all regions. These integrals cannot be calculated without regularization, in spite of the fact that they yield a finite result. A typical example where such integrals occur is the decay H →γγ.
Scaling of average weighted shortest path and average receiving time on weighted expanded Koch networks
Authors: Wu Zikai , Hou Baoyu , Zhang Hongjuan , Jin Feng
Published: April 2014

Deterministic network models have been attractive media for discussing dynamical processes' dependence on network structural features. On the other hand, the heterogeneity of weights affect dynamical processes taking place on networks. In this paper, we present a family of weighted expanded Koch networks based on Koch networks. They originate from a r-polygon, and each node of current generation produces m r-polygons including the node and whose weighted edges are scaled by factor w in subsequent evolutionary step. We derive closed-form expressions for average weighted shortest path length (AWSP). In large network, AWSP stays bounded with network order growing (0 < w < 1). Then, we focus on a special random walks and trapping issue on the networks. In more detail, we calculate exactly the average receiving time (ART). ART exhibits a sub-linear dependence on network order (0 < w < 1), which implies that nontrivial weighted expanded Koch networks are more efficient than un-weighted expanded Koch networks in receiving information. Besides, efficiency of receiving information at hub nodes is also dependent on parameters m and r. These findings may pave the way for controlling information transportation on general weighted networks.
Thermal conductance attributed to phonon and electron in graphene nanoribbon
Authors: Ye En-Jia , Shi Yi-Jian , Shi Lihong , Zhao Xuean
Published: April 2014

In this work, the energy transport of phonon and electron in graphene nanoribbons (GNRs) are investigated by the nonequilibrium Green's function method without considering the interaction of phonon and electron. The heat current of phonon contribution comes from the gradient of temperature. While for the electron contribution, it stems from the gradient of both temperature and electrochemical potential. The corresponding intermediate functions satisfy the Onsager relationship. Thermal conductances are calculated in GNR and compared to those in square lattice ribbon model respectively. It is found that both the phonon and electron thermal conductances in square lattice ribbon are smaller than those in GNRs at low temperature and surpass those in armchair and zigzag GNRs respectively, as the temperature increases. Meanwhile, the heat transport is related to the edges of GNRs. These phenomena depend on their dispersion relations and energy band structures.
Nano-multiwall cylinders array for ultra-broadband perfect absorption in visible regime: novel properties revealing
Authors: Han Qi , Jin Lei , Fu Yongqi , Yu Weixing
Published: April 2014

An extraordinary light absorption property of nano-multiwall cylinder array with a periodic structure is reported. The ultra-high absorption is independent of the incoming light on polarization state and insensitive in a broad angle range. We attribute the efficient light harvesting property of nano-multiwall cylinder array to the leaky-mode resonance. Influence of geometrical parameters of the structure such as wall cylinder height, width, and substrate thickness on absorbing performance is discussed. The proposed absorber will find its application in those areas related to solar energy harvesting.
Antioscillons from bubble collisions at finite temperature
Authors: Mersini-Houghton Laura
Published: April 2014

We study the role of the topology of bubbles at finite temperatures plays on collisions and the existence of new field configurations. We show that in the case of false vacuum decay at finite temperature, the cylindrical symmetry of bubbles admits a new exotic field with negative energies, the antiperiodic "twisted" field. New field configurations arise generically, not only at finite temperatures but whenever a cluster of bubbles resulting from collisions form nontrivial topologies. The interaction of both configurations induces instabilites on the bubble. Collisions of bubbles occupied by the new fields can lead to the emergence of new structures, named antioscillons.
The single-biopsy approach in determining protein synthesis in human slow-turning-over tissue: use of flood-primed, continuous infusion of amino acid tracers
Authors: Holm Lars , Reitelseder Søren , Dideriksen Kasper , Nielsen Rie H. , Bülow Jacob , Kjaer Michael
Published: April 2014

Muscle protein synthesis (MPS) rate is determined conventionally by obtaining two or more tissue biopsies during a primed, continuous infusion of a stable isotopically labeled amino acid. The purpose of the present study was to test whether tracer priming given as a flooding dose, thereby securing an instantaneous labeling of the tissue pools of free tracee amino acids, followed by a continuous infusion of the same tracer to maintain tracer isotopic steady state, could be used to determine the MPS rate over a prolonged period of time by obtaining only a single tissue biopsy. We showed that the tracer from the flood prime appeared immediately in the muscle free pool of amino acids and that this abundance could be kept constant by a subsequent continuous infusion of the tracer. When using phenylalanine as tracer, the flood-primed, continuous infusion protocol does not stimulate the MPS rate per se. In conclusion, the flood-primed, continuous infusion protocol using phenylalanine as tracer can validly be used to measure the protein synthesis rate in human in vivo experiments by obtaining only a single tissue biopsy after a prolonged infusion period.
Mice lacking NOX2 are hyperphagic and store fat preferentially in the liver
Authors: Costford Sheila R. , Castro-Alves Jason , Chan Kenny L. , Bailey Liane J. , Woo Minna , Belsham Denise D. , Brumell John H. , Klip Amira
Published: April 2014

Chronic low-grade inflammation is an important contributor to the development of insulin resistance, a hallmark of type 2 diabetes mellitus (T2DM). Obesity and high-fat feeding lead to infiltration of immune cells into metabolic tissues, promoting inflammation and insulin resistance. We hypothesized that macrophages from mice lacking NOX2 ( Cybb), an essential component of the NADPH oxidase complex highly expressed in immune cells and associated with their inflammatory response, would be less inflammatory and that these mice would be protected from the development of high-fat-induced insulin resistance. Bone marrow-derived macrophages from NOX2 knockout (NOX2-KO) mice expressed lower levels of inflammatory markers ( Nos2, Il6); however, NOX2-KO mice were hyperphagic and gained more weight than wild-type (WT) mice when fed either a chow or a high-fat (HF) diet. Surprisingly, NOX2-KO mice stored less lipid in epididymal white adipose tissue but more lipid in liver and had higher indexes of liver inflammation and macrophage infiltration than WT mice. Contrary to our hypothesis, HF-fed NOX2-KO mice were hyperinsulinemic and more insulin resistant than HF-fed WT mice, likely as a result of their higher hepatic steatosis and inflammation. In summary, NOX2 depletion promoted hyperphagia, hepatic steatosis, and inflammation with either normal or high-fat feeding, exacerbating insulin resistance. We propose that NOX2 participates in food intake control and lipid distribution in mice.
Dietary flaxseed intake exacerbates acute colonic mucosal injury and inflammation induced by dextran sodium sulfate
Authors: Zarepoor Leila , Lu Jenifer T. , Zhang Claire , Wu Wenqing , Lepp Dion , Robinson Lindsay , Wanasundara Janitha , Cui Steve , Villeneuve Sébastien , Fofana Bourlaye , Tsao Rong , Wood Geoffrey A. , Power Krista A.
Published: April 2014

Flaxseed (FS), a dietary oilseed, contains a variety of anti-inflammatory bioactives, including fermentable fiber, phenolic compounds (lignans), and the n-3 polyunsaturated fatty acid (PUFA) α-linolenic acid. The objective of this study was to determine the effects of FS and its n-3 PUFA-rich kernel or lignan- and soluble fiber-rich hull on colitis severity in a mouse model of acute colonic inflammation. C57BL/6 male mice were fed a basal diet (negative control) or a basal diet supplemented with 10% FS, 6% kernel, or 4% hull for 3 wk prior to and during colitis induction via 5 days of 2% (wt/vol) dextran sodium sulfate (DSS) in their drinking water ( n = 12/group). An increase in anti-inflammatory metabolites (hepatic n-3 PUFAs, serum mammalian lignans, and cecal short-chain fatty acids) was associated with consumption of all FS-based diets, but not with anti-inflammatory effects in DSS-exposed mice. Dietary FS exacerbated DSS-induced acute colitis, as indicated by a heightened disease activity index and an increase in colonic injury and inflammatory biomarkers [histological damage, apoptosis, myeloperoxidase, inflammatory cytokines (IL-6 and IL-1β), and NF-κB signaling-related genes (Nfkb1, Ccl5, Bcl2a1a, Egfr, Relb, Birc3, and Atf1)]. Additionally, the adverse effect of the FS diet was extended systemically, as serum cytokines (IL-6, IFNγ, and IL-1β) and hepatic cholesterol levels were increased. The adverse effects of FS were not associated with alterations in fecal microbial load or systemic bacterial translocation (endotoxemia). Collectively, this study demonstrates that although consumption of a 10% FS diet enhanced the levels of n-3 PUFAs, short-chain polyunsaturated fatty acids, and lignans in mice, it exacerbated DSS-induced colonic injury and inflammation.