bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulation phenomena in Si nanowire field-effect transistors characterized using noise spectroscopy and gamma radiation technique
Authors: Pud S. , Li J. , Petrychuk M. , Feste S. , Vitusevich S. , Danilchenko B. , Offenhäusser A. , Mantl S.
Published: March 2013

High-quality silicon nanowire (NW) field-effect transistors (FETs) were designed and fabricated. Features of transport and modulation phenomena of the structures were studied using a number of techniques, including noise spectroscopy. Using the 1/f noise component level, the values of the volume trap densities in gate dielectric are estimated to be around 1 × 1017 cm−3 eV−1. This result proves high quality of the investigated structures. Analysis of Lorentzian noise components of NW samples is used to characterize single trap and its parameters. A strong modulation of carrier concentration in the conducting channel under influence of even single carrier capture event has been revealed. Possibility of fine tuning of the transport properties of the sample with low-dose gamma irradiation has been shown. The gamma radiation treatment of the NW samples was applied as an effective technique to confirm the strong influence of trap charges on conductivity behavior in the channel of NW FETs. The results demonstrate that the modulation effects at the nanoscale enable effective changing of the channel conductivity by single capture events and thus are promising for future information technologies and ultra-sensitive single-molecular sensor applications.
Jet theoretical Yang-Mills energy in the geometric dynamics of two-dimensional monolayer
Authors: Neagu M. , Krylova N. G. , Grushevskaya H. V.
Published: March 2013

Langmuir-Blodgett (LB)-films consist of few LB-monolayers which are high structured nanomaterials that are very promising materials for applications. We use a geometrical approach to describe a structurization into LB-monolayers. Consequently, we develop on the 1-jet space \documentclass[12pt]{minimal}\begin{document}$J^{1}([0,\infty ),\mathbb {R}^{2})$\end{document}J1([0,∞),R2) the single-time Lagrange geometry (in the sense of distinguished (d-) connection, d-torsions, and an abstract anisotropic electromagnetic-like d-field) for the Lagrangian governing the 2D-motion of a particle of monolayer. One assumed that an expansion near singular points for the constructed geometrical Lagrangian theory describes phase transitions to LB-monolayer. Trajectories of particles in a field of the electrocapillarity forces of monolayer have been calculated in a resonant approximation utilizing a Jacobi equation. A jet geometrical Yang-Mills energy is introduced and some computer graphic simulations are exposed.
Combined effect of Sn addition and post-rolling sintering on the superconducting properties of SmFeAsO1−xFx tapes fabricated by an ex-situ powder-in-tube process
Authors: Zhang Qianjun , Wang Chunlei , Yao Chao , Lin He , Zhang Xianping , Wang Dongliang , Ma Yanwei , Awaji Satoshi , Watanabe Kazuo
Published: March 2013

Polycrystalline Sn-added SmFeAsO1−xFx tapes were prepared by an ex-situ powder-in-tube method. It is found that the transport critical current density (Jc) of the SmFeAsO1−xFx tapes can be significantly improved with 10-30 wt. % Sn addition. A transport Jc of 2.11 × 104 A cm−2 at 4.2 K in self-field was obtained in SmFeAsO1−xFx + 30 wt. % Sn sample. Most interestingly, Sn-added SmFeAsO1−xFx tapes without any sintering also showed substantial transport Jc of 9.81 × 103 A cm−2, which is reported for the first time. X-ray diffraction and scanning electron microscopy characterization revealed that the elemental Sn dispersed in the sample transformed into FeSn2 during the post-rolling sintering (PRS). The reaction between Sn and FeAs helps to eliminate the detrimental FeAs wetting phase, which blocks the supercurrent path between SmFeAsO1−xFx grains. The combined impact of fluorine loss and Sn reaction was discussed in this work by varying the Sn addition quantity and PRS condition.
Magnetic and structural properties of the new double perovskite family Sr2GdRu1−xRexOy
Authors: Corredor L. T. , Roa-Rojas J. , Landínez Téllez D. A. , Beltrán R. , Pureur P. , Mesquita F. , Albino Aguiar J.
Published: March 2013

We study the synthesis and structural and magnetic characterization of the new compound family Sr2GdRu1−xRexOy, with doping levels at 3%, 6%, 9%, and 12%. X-ray diffractograms revealed that the samples crystallize in a monoclinic structure, and exhibit a strong distortion of the octahedron Ru(Re)O6/GdO6 lattice. Magnetic characterization revealed non-ideal antiferromagnetic behavior, with Néel temperatures close to 25 K, and an interesting metamagnetic feature below applied magnetic fields between 1.0 and 1.4 T. The existence of a Re doping level limit that favors an ideal antiferromagnetic character of the perovskite is discussed.
Field dependent magnetic anisotropy of Fe1−xZnx thin films
Authors: Resnick Damon A. , McClure A. , Kuster C. M. , Rugheimer P. , Idzerda Y. U.
Published: March 2013

Using longitudinal magneto-optical Kerr effect in combination with a variable strength rotating magnetic field, called the Rotational Magneto-Optic Kerr Effect (ROTMOKE) method, we show that the magnetic anisotropy for thin Fe82Zn18 single crystal films, grown on MgO(001) substrates, depends linearly on the strength of the applied magnetic field at low fields but is constant (saturates) at fields greater than 350 Oe. The torque moment curves generated using ROTMOKE are well fit with a model that accounts for the uniaxial and cubic anisotropy with the addition of a cubic anisotropy that depends linearly on the applied magnetic field. The field dependent term is evidence of a large effect on the effective magnetic anisotropy in Fe1−xZnx thin films by the magnetostriction.
Effects of residual and tunable strain in thin films of La0.7Ba0.3MnO3
Authors: Wang J. F. , Jiang Y. C. , Wu Z. P. , Gao J.
Published: March 2013

The effects of residual and tunable strain in thin films of La0.7Ba0.3MnO3 (LBMO) were investigated. Different residual strains were achieved by depositing LBMO films with various thicknesses on 0.7PbMg1/3Nb2/3O3–0.3PbTiO3 (PMN-PT) and SrTiO3 (STO). For LBMO on PMN-PT, when the thickness changes the resistance evolves dramatically. All samples on STO have a clear metal-to-insulator transition near room temperature. The tunable strain was modulated through the converse piezoelectric effects of PMN-PT. Clear voltage-controlled resistance modulations (|ΔR|/Rmax ∼ 90%) were observed in LBMO/PMN-PT. The magnitude and nonlinearity of elastoresistance are the largest in the thinnest sample. |ΔR|/R decreases as the thickness increases and is still substantial even the film is as thick as 150 nm. For thicker samples, the nonlinearity becomes weaker and the resistance changes linearly with voltage approximately.
Hybrid proton acceleration scheme using relativistic intense laser light
Authors: Andreev A. A. , Platonov K. Yu. , Schnürer M. , Prasad R. , Ter-Avetisyan S.
Published: March 2013

Ion acceleration phenomena at relativistic intense laser interaction with thin foil targets are studied to find an efficient laser-target interaction concept at the conditions, where neither the ponderomotive pressure of the laser light nor the hot electron pressure is negligible. Particle in cell simulations and the analytical model are allowing to predict optimum laser-target parameters and suggesting a significant increase of proton energy if a hybrid proton acceleration scheme is used. In the proposed scenario, the laser polarisation is changed during the acceleration process: First with circularly polarised laser light the target is accelerated as a whole by the ponderamotive pressure, and then with linearly polarised laser light the electrons are heated which additionally increases the accelerating field. The calculations are in good agreement with experimental findings.
A study of the T2 defect and the emission properties of the E3 deep level in annealed melt grown ZnO single crystals
Authors: Mtangi W. , Schmidt M. , Auret F. D. , Meyer W. E. , Janse van Rensburg P. J. , Diale M. , Nel J. M. , Das A. G. M. , Ling F. C. C. , Chawanda A.
Published: March 2013

We report on the space charge spectroscopy studies performed on thermally treated melt-grown single crystal ZnO. The samples were annealed in different ambients at 700 °C and also in oxygen ambient at different temperatures. A shallow donor with a thermal activation enthalpy of 27 meV was observed in the as-received samples by capacitance-temperature, CT scans. After annealing the samples, an increase in the shallow donor concentrations was observed. For the annealed samples, E27 could not be detected and a new shallow donor with a thermal activation enthalpy of 35 meV was detected. For samples annealed above 650 °C, an increase in acceptor concentration was observed which affected the low temperature capacitance. Deep level transient spectroscopy revealed the presence of five deep level defects, E1, E2, E3, E4, and E5 in the as-received samples. Annealing of the samples at 650 °C removes the E4 and E5 deep level defects, while E2 also anneals-out at temperatures above 800 °C. After annealing at 700 °C, the T2 deep level defect was observed in all other ambient conditions except in Ar. The emission properties of the E3 deep level defect are observed to change with increase in annealing temperature beyond 800 °C. For samples annealed beyond 800 °C, a decrease in activation enthalpy with increase in annealing temperature has been observed which suggests an enhanced thermal ionization rate of E3 with annealing.
Magnetic antibubbles: Formation and control of magnetic macroemulsions for fluid transport applications
Authors: Silpe Justin E. , McGrail David W.
Published: March 2013

We report the first instance of so called magnetic antibubbles wherein the internal phase comprises an aqueous dispersion of iron oxide (Fe3O4) microparticles, and is thus capable of external control in the presence of a magnetic field. Formation of these bubbles is performed by jetting an iron oxide dispersed phase, through a gaseous medium, into a surrounding aqueous phase. At appropriate trajectory and flow rate conditions, a gas layer is entrained between the two liquids, encapsulating the internal, iron oxide core from the surrounding aqueous phase. We demonstrate that the application of a nonuniform magnetic field confers maneuverability to these bubbles, the intensity of which determines whether the Fe3O4 particles move with the antibubble intact or accelerate through the air layer causing its collapse. An externally applied magnetic field proves a sensitive and determinative means of control, and thus we believe that the magnetic antibubble represents a unique candidate for various fluid delivery and transport applications.
Beam and phase distributions of a terahertz quantum cascade wire laser
Authors: Cui M. , Hovenier J. N. , Ren Y. , Vercruyssen N. , Gao J. R. , Kao T. Y. , Hu Q. , Reno J. L.
Published: March 2013

We report on both measurements and simulations of the beam profile and wavefront of a single-mode, 3.5 THz quantum cascade wire laser, incorporating a lateral corrugated metal-metal waveguide, 3rd-order distributed feedback grating. The intrinsic wavefront was measured by using a Hartmann wavefront sensor (HWS) without any optical components between the laser and HWS. Both beam profile and wavefront were simulated using an antenna array model, but taking the non-uniform electric field distribution along the waveguide into account. The results show that the non-uniform distribution along the wire laser plays a crucial role in realizing a nearly single-lobed narrow beam. The measured wavefront is spherical and agrees well with the simulation.
Electrical conduction of carbon nanotube forests through sub-nanometric films of alumina
Authors: Esconjauregui Santiago , Xie Rongsi , Guo Yuzheng , Pfaendler Sieglinde M.-L. , Fouquet Martin , Gillen Roland , Cepek Cinzia , Castellarin-Cudia Carla , Eslava Salvador , Robertson John
Published: March 2013

We report both the growth of carbon nanotube forests and electrical conduction on W, Ti, and TiN substrates coated with an ultra-thin Al2O3 support layer. Varying the Al2O3 thickness, a good electrical contact and high nanotube density is possible for a 0.5 nm Al2O3 layer as such an ultra-thin film allows tunnelling. X-ray photoelectron spectroscopy shows that, when using these non-continuous Al2O3 films, Fe catalyst diffuses into the conducting substrates, eventually causing growth to stop. Forests grown on ultra-thin Al2O3 are potentially useful for applications as interconnects, supercapacitors, and heat spreaders.
Effect of forming gas annealing on the ferroelectric properties of Hf0.5Zr0.5O2 thin films with and without Pt electrodes
Authors: Hyuk Park Min , Joon Kim Han , Jin Kim Yu , Lee Woongkyu , Kyeom Kim Hyo , Seong Hwang Cheol
Published: March 2013

The effects of forming gas annealing (FGA) on the ferroelectric properties of Hf0.5Zr0.5O2 (HZO) films were examined. Although the H-incorporation during FGA degrades the ferroelectric properties of Hf0.5Zr0.5O2 films, the degree of degradation was much lower compared with other ferroelectrics, such as Pb(Zr,Ti)O3. Pt worked as a catalyst for H-incorporation, and maximum 2Pr loss of ∼40% occurred. However, the insertion of a ∼20-nm-thick TiN layer between Pt and Hf0.5Zr0.5O2 decreased the degradation to ∼12%. Hf0.5Zr0.5O2 is more resistant to degradation by FGA compared with the conventional ferroelectrics, which is a highly promising result for next-generation ferroelectric memory.
Origin of the superior conductivity of perovskite Ba(Sr)SnO3
Authors: Liu Heng-Rui , Yang Ji-Hui , Xiang H. J. , Gong X. G. , Wei Su-Huai
Published: March 2013

ASnO3 (A = Ba, Sr) are unique perovskite oxides in that they have superior electron conductivity despite their wide optical band gaps. Using first-principles band structure calculations, we show that the small electron effective masses, thus, good electron conductivity of ASnO3 can be attributed to the large size of Sn in this system that gives the conduction band edge with antibonding Sn and Os characters. Moreover, we show that ASnO3 can be easily doped by La with shallow LaA(+/0) donor level. Our results, therefore, explain why the perovskite BaSnO3, SrSnO3, and their alloys are promising candidates for transparent conducting oxides.
Baby leafy green vegetables: providing insight into an old problem? An exploratory qualitative study examining influences on their consumption
Authors: McMahon Anne‐Therese , Tapsell Linda , Williams Peter , Jobling Jennifer
Published: March 2013

Issue addressed

Populations in many developed countries continue to fail to meet vegetable consumption recommendations despite ongoing health promotion activities supported by public health policies. Novel ways to encourage vegetable consumption may help address this concern. The aim of the present study was to describe female consumers' perceptions about leafy green vegetables and identify consumption issues.

Methods

Three age‐stratified semistructured focus groups were conducted with 23 female participants. Food shopping habits, reported consumption and/or knowledge, and the perceived benefits of and/or issues associated with the consumption of leafy green vegetables were explored. Focus groups were transcribed verbatim. Two researchers examined each transcript in conjunction with accompanying observers' notes. Content and thematic analysis was conducted to identify final themes.

Results

Three key themes were identified: (1) food selection is influenced by time limitations, convenience factors and quality considerations; (2) the repertoire of vegetables is influenced by acceptability within households, familiarity and culinary confidence; and (3) connection with nutritional value is influenced by existing beliefs and knowledge of the nutrient content of leafy green vegetables. Variations found on self‐reported intake and acceptability were related to life stage and needs.

Conclusions

Leafy green varieties were perceived as important contributors to a healthy diet. Key barriers to consumption identified in the thematic review related to time constraints, culinary skills and variations in nutritional knowledge.

So what?

Primary awareness of vegetables as being critical to a healthy diet has been established. Future health promotion activities could focus more on convenience, nutrient quality and versatility of leafy green vegetables, and other similar vegetables, as a way to increase total consumption.
Using evidence in health promotion in local government: contextual realities and opportunities
Authors: Pettman Tahna Lee , Armstrong Rebecca , Pollard Ben , Evans Rachel , Stirrat Amanda , Scott Isha , Davies‐Jackson Georgia , Waters Elizabeth
Published: March 2013

Issue addressed

New national and state preventive health investments have provided significant funding for local governments (LGs) to be involved in planning and implementing health promotion interventions. There is an expectation that this work is evidence based; however, inadequate support and systems exist for evidence‐informed planning and decision making in LGs. Previous initiatives have aimed to build capacity and leadership in LG health promotion, but the training, support and infrastructure have been sporadic.

Methods

Across 2009–11 we implemented a National Health and Medical Research Council of Australia (NHMRC)‐funded university‐LG research project to explore the feasibility, usefulness and outcomes of a knowledge translation (KT) intervention to increase the use of evidence in LGs. Within this exploratory cluster randomised controlled trial, one strategy being evaluated was workforce capacity building, during which group discussions revealed contextual challenges in delivering evidence‐informed health promotion within the current funding context. Discussion was recorded. The group acknowledged the need to identify barriers and realistic practical solutions, and to communicate these more broadly.

Results

Barriers to sourcing and applying evidence to inform health promotion emerged from discussions with LG representatives. System‐level contextual factors affecting decisions were also discussed, namely concerns about organisational capacity and ‘culture’ to plan, implement and evaluate effective initiatives in LGs. Possible solutions suggested included: systems for access to academic literature; processes that make it easier to use evidence; training in evidence‐informed health promotion to build organisational culture and capacity; and research‐practice partnerships and mentoring.

Conclusions

Targeted strategies with individuals (LG staff) and organisations (leadership, systems) are needed to realise the potential of current health promotion investments. Research‐practice partnerships are likely to be important. It seems obvious that it is impossible to be evidence informed without mechanisms to access and apply evidence. We invite other LGs to reflect upon their experiences in such initiatives, and to consider whether the strategies we propose may be useful.

So what?

The increased emphasis on health promotion and non‐communicable disease prevention programs may be limited by the capacity, confidence and organisational culture to inform policies and programs with best‐available evidence. We describe some of the current challenges and contextual factors as they are being experienced. There are opportunities for national and state governments, organisations representing local government (e.g. municipal associations) and research partners to provide targeted support to councils. This may assist in achieving effective health promotion at the community level.
Champions in a lifestyle risk‐modification program: reflections on their training and experiences
Authors: Aoun Samar , Shahid Shaouli , Le Linda , Holloway Kristi
Published: March 2013

Issues addressed

The ‘Waist’ Disposal Challenge (WDC) is a lay‐led community‐based health intervention in Rotary clubs in Western Australia aimed at reducing risk factors leading to lifestyle‐related chronic diseases and, in particular, obesity. Ninety‐three lay health advisors (LHA) or Champions were trained to deliver educational sessions to their clubs (for 1300 peers) and implement a body mass index competition by taking monthly weigh‐ins (for 764 peers).

Methods

A mixed method design was used to explore Champions' experiences with the training program and their perceived role and impact on implementing the program in their clubs in 2010–11.

Results

The qualitative data provided important evidence that initial implementation of this LHA‐led health promotion intervention (WDC) has been effective and impacted positively on the Champions and their Rotary clubs. The results were a good fit in the two social action arenas of the Natural Helper Intervention Model: peer‐to‐peer social support and community attachment.

Conclusions

Reflecting on the impact of the program in their clubs, Champions reported overall health improvements at the personal, peer and community levels, enhanced awareness about health‐related issues, improved health behaviour and enhanced community capacity.

So what?

Champions are an important resource for providing self‐management education to people who are at risk of developing chronic conditions, particularly for those hard to reach and where there are difficulties recruiting trained health professionals. Future research needs to explore the characteristics of Champions that impact on the success of community‐based programs.
Health priorities and perceived health determinants among Western Australians attending the 2011 LGBTI Perth Pride Fairday Festival
Authors: Comfort Jude , McCausland Kahlia
Published: March 2013

Issue addressed

Although data exist demonstrating poorer health indicators on a range of health outcomes for lesbian, gay, bisexual, transsexual and intersex (LGBTI) people, there is little information as to how this group perceives the relative importance of different health issues or what the underlying reasons behind poorer health may be.

Method

A self‐completed survey was administered to people attending the October 2011 LGBTI Perth Pride Fairday Festival. Three hundred and fifty‐one people completed the survey, resulting in a total of 335 useable surveys. One hundred and seventy‐eight participants identified as female, 145 as male, four as transgender and eight as other genders.

Results

Depression, anxiety, excessive worry or panic attacks and problems in family relationships were reported as the most important individual health issues, whereas depression, suicide and HIV/AIDS were seen as the most important health issues affecting the LGBTI community. Discrimination was rated the most important social factor impacting on the health and well being of this community.

Conclusions

When members of the LGBTI community were asked to rank health issues of importance both individually and as a community, the results indicate that mental health issues are of prime concern. Discrimination and the stress of living as part of this minority group were seen as contributing to this. Health promotion and public health need to be responsive to these issues if real gains are to be made in reducing the health inequities affecting this group.

So what?

This research highlights the link between social justice, social inclusion and health outcomes. The health of LGBTI people is rarely considered by mainstream agencies, despite poorer health outcomes. Sensitive and targeted public health interventions that resonate with the community and that acknowledge the impact of being part of this marginalised group are required.
Health promotion and crime prevention: recognising broader synergies
Authors: Young Janette , Sarre Rick
Published: March 2013

Issue addressed

Although health promotion and crime prevention have been brought together to address specific social ills, such as illicit drugs and road trauma, there is little literature that seeks to lift the connections between the fields of health and justice to a more general level.

Methods

The present paper explores the synergies between health promotion and crime prevention by considering a range of parallels between them.

Results

Health promotion and crime prevention can be shown to have several parallel interests, agendas, systemic locations and shared population foci, indicating a potential for more conscious engagement between each field.

Conclusion

There are a range of synergies, parallels and shared interests that crime prevention and health promotion share. These fields could develop more supportive networks with each other.

So what?

There is scope for those who champion both crime prevention and health promotion to align more readily in activities of public policy, academia and practice. In addition, the two fields and their advocates could be more supportive of each other in progressing agendas of social equity. Health promotion practitioners could consider seeking to extend their employment and opportunities by being aware of projects, employment and relationships outside of health in the field of crime prevention.
Eye health promotion to improve awareness and prevent vision loss among Indigenous Australians
Authors: Boudville Andrea I. , Anjou Mitchell D. , Taylor Hugh R.
Published: March 2013

Vision loss in Australian Indigenous communities can be largely prevented if appropriate eye care services are provided and accessed. Our extensive consultations across Australia identify opportunities to improve community and health provider awareness through eye health promotion. An improved awareness of eye care, service availability, and when and how to seek care, will contribute to closing the gap for vision.
New approaches for tackling the khapra beetle.
Authors: Eliopoulos P. A.
Published: March 2013

The khapra beetle,
Trogoderma granarium
Everts (Coleoptera: Dermestidae) is a very destructive pest of stored agricultural products and one of the most important quarantine insect pests worldwide. Very strict legislation and other measures are being taken by many countries so as to prevent the introduction of this pest and avoid export restrictions on their agricultural products. In countries where the khapra beetle is established or occasionally detected, classic management tactics are being improved and new methods are being developed in order to prevent the spread of the infestation or to eradicate, if possible, this feared pest. This review aims not only to provide insight in recent advances on identification, detection, exclusion and control methods of
T. granarium
, but also to consolidate the available recent and older information and provide an analysis of the published work. Potential areas for growth in the management of khapra beetle include, among others, rapid molecular identification, trapping, combination of fumigation with modified atmospheres or heat, irradiation and plant extracts. Certain advantages, limitations, mode of action, potentiality and effectiveness of each method are discussed.
A property of Peano derivatives in several variables
Authors: Fejzić Hajrudin , Weil Clifford
Published: March 2013

Let

f
f

be a function of several variables that is

n
n

times Peano differentiable. Andreas Fischer proved that if there is a number

M
M

such that

f

α

≥
M

f_{\boldsymbol {\alpha } } \ge M

or

f

α

≤
M

f_{\boldsymbol {\alpha } } \le M

for each

α
\boldsymbol {\alpha }

, with

|
α
|

=
n

\left | \boldsymbol {\alpha } \right | = n

, then

f
f

is

n
n

times differentiable in the usual sense. Here that result is improved to permit the type of one-sided boundedness to depend on

α
\boldsymbol {\alpha }

.
Ranolazine-Induced Myopathy in a Patient on Chronic Statin Therapy
Authors: Correa Daniel , Landau Mark
Published: March 2013

We present a case demonstrating clinical, electrophysiological, serological, and radiological evidence of a myopathy induced by ranolazine, in a patient otherwise asymptomatic on chronic statin therapy. The patient developed proximal weakness, serum creatine kinase levels of 1875 U/L, electromyography with muscle membrane instability and small short-duration motor unit potentials, and magnetic resonance imaging evidence of muscle edema. The manifestations began within one week of initiation of ranolazine and improved within days after discontinuation. Ranolazine is a weak inhibitor of CYP3A4 known to increase the serum level of simvastatin and its active metabolite 2-fold. We postulate that the addition of ranolazine to a medical regimen that included atorvastatin induced a myoncecrotic myopathy.
Listeria monocytogenes ArcA contributes to acid tolerance
Authors: Cheng Changyong , Chen Jianshun , Shan Ying , Fang Chun , Liu Yuan , Xia Ye , Song Houhui , Fang Weihuan
Published: March 2013

The foodborne pathogenListeria monocytogenesis able to colonize the human and animal intestinal tracts and subsequently crosses the intestinal barrier, causing systemic infection. For successful establishment of infection,L. monocytogenesmust survive and adapt to the low pH environment of the stomach. Gene sequence analysis indicates thatlmo0043, an orthologue ofarcA, encodes a protein containing conserved motifs and critical active amino acids characteristic of arginine deiminase that mediates an arginine deimination reaction. We attempted to characterize the role of ArcA in acid tolerancein vitroand in mice models. Transcription ofarcAwas significantly increased inL. monocytogenesculture subjected to acid stress at pH 4.8, as compared with that at pH 7.0. Deletion ofarcAimpaired growth ofL. monocytogenesunder mild acidic conditions at pH 5.5, and reduced its survival in synthetic human gastric fluid at pH 2.5 and in the murine stomach. Bacterial load in the spleen of mice intraperitoneally inoculated with anarcAdeletion mutant was significantly lower than that of the wild-type strain. These phenotypic changes were recoverable by genetic complementation. Thus, we conclude thatL. monocytogenes arcAnot only mediates acid tolerancein vitrobut also participates in gastric survival and virulence in mice.
Co-existence of bla
OXA-23 and armA in multidrug-resistant Acinetobacter baumannii isolated from a hospital in South Korea
Authors: Hong Seung Bok , Shin Kyeong Seob , Ha Jungsu , Han Kyudong
Published: March 2013

The co-existence of carbapenemase, 16S rRNA methylase and mutated quinolone resistance-determining regions (QRDRs) can cause serious difficulty in treating infections with multidrug-resistant Acinetobacter baumannii. In this study, we aimed to determine the mechanisms of imipenem, amikacin and ciprofloxacin resistance in A. baumannii isolates with resistance to these antibiotics. A total of 31 non-duplicate isolates of amikacin- and ciprofloxacin-resistant Acinetobacter isolates were identified from April to August 2010 from a single hospital in South Korea. To assess the clonal relatedness of the 31 Acinetobacter isolates, multilocus sequence typing, network phylogenetic analysis and enterobacterial repetitive intergenic consensus-PCR were utilized. Detection of OXA-type carbapenemase and 16S rRNA methylase was conducted using a multiplex PCR assay. The QRDRs of the gyrA and parC genes were amplified and sequenced. The result showed that 30/31 isolates harboured the bla
OXA-23-like carbapenemase, which made them resistant to imipenem (MICs ≥16 µg ml−1). Twenty-eight of the 31 isolates were found to possess armA, a 16S rRNA methylase gene, and showed resistance to amikacin, arbekacin, gentamicin and tobramycin (MICs >256 µg ml−1). All of the isolates were determined to carry QRDR mutations in both gyrA and parC: a Ser83Leu substitution in gyrA and a Ser80Leu substitution in parC, causing a ciprofloxacin MIC ≥64 µg ml−1. In conclusion, A. baumannii with co-existence of carbapenemase, 16S rRNA methylase and mutated QRDRs are extremely prevalent in South Korea, which may cause serious problems in the treatment of A. baumannii infections using carbapenem, amikacin and ciprofloxacin.
Germination efficiency of clinical Clostridium difficile spores and correlation with ribotype, disease severity and therapy failure
Authors: Moore P. , Kyne L. , Martin A. , Solomon K.
Published: March 2013

Spore germination is an important part of the pathogenesis of Clostridium difficile infection (CDI). Spores are resistant to antibiotics, including those therapeutically administered for CDI and strains with a high germination rate are significantly more likely to be implicated in recurrent CDI. The role of germination efficiency in cases of refractory CDI where first-line therapy fails remains unclear. We investigated spore germination efficiencies of clinical C. difficile isolates by measuring drop in OD600 and colony forming efficiency. Ribotype 027 isolates exhibited significantly higher germination efficiencies in the presence of 0.1 % (w/v) sodium taurocholate (51.66±8.75 %; 95 % confidence interval (CI) 47.37–55.95 %) than ribotype 106 (41.91±8.35 %; 95 % CI 37.82–46 %) (P<0.05) and ribotype 078 (42.07±8.57 %, 95 % CI 37.22–46.92 %) (P<0.05). Spore outgrowth rates were comparable between the ribotype groups but the exponential phase occurred approximately 4 h later in the absence of sodium taurocholate. Spore germination efficiencies for isolates implicated in severe CDI were significantly higher (49.68±10.00 %, 95 % CI 47.06–52.30 %) than non-severe CDI (40.92±9.29 %, 95 % CI 37.48–44.36 %); P<0.01. Germination efficiencies were also significantly higher in recurrent CDI or when metronidazole therapy failed than when therapy was successful [(49.00±10.49 %, 95 % CI 46.25–51.75 %) versus (41.42±9.43 %, 95 % CI 37.93–44.91 %); P<0.01]. This study suggests an important link between C. difficile spore germination, CDI pathogenesis and response to treatment; however, further work is warranted before the complex interplay between germination dynamics and CDI outcome can be fully understood.
The impact of body mass index on maternal and neonatal outcomes: a retrospective study in a UK obstetric population, 2004–2011
Authors: Scott‐Pillai R , Spence D , Cardwell CR , Hunter A , Holmes VA
Published: March 2013

Objective

To assess the prevalence of overweight and obesity, and the impact of body mass index (BMI) on maternal and neonatal outcomes, in a UK obstetric population.

Design

Retrospective study.

Setting

A tertiary referral unit in Northern Ireland.

Population

A total of 30 298 singleton pregnancies over an 8‐year period, 2004–2011.

Methods

Women were categorised according to World Health Organization classification: underweight (BMI < 18.50 kg/m2); normal weight (BMI 18.50–24.99 kg/m2; reference group); overweight (BMI 25.00–29.99 kg/m2); obese class I (BMI 30.00–34.99 kg/m2); obese class II (BMI 35–39.99 kg/m2); and obese class III (BMI ≥ 40 kg/m2). Maternal and neonatal outcomes were examined using logistic regression, adjusted for confounding variables.

Main outcome measures

Maternal and neonatal outcomes.

Results

Compared with women of normal weight, women who were overweight or obese class I were at significantly increased risk of hypertensive disorders of pregnancy (OR 1.9, 99% CI 1.7–2.3; OR 3.5, 99% CI 2.9–4.2); gestational diabetes mellitus (OR 1.7, 99% CI 1.3–2.3; OR 3.7, 99% CI 2.8–5.0); induction of labour (OR 1.2, 99% CI 1.1–1.3; OR 1.3, 99% CI 1.2–1.5); caesarean section (OR 1.4, 99% CI 1.3–1.5; OR 1.8, 99% CI 1.6–2.0); postpartum haemorrhage (OR 1.4, 99% CI 1.3–1.5; OR 1.8, 1.6–2.0); and macrosomia (OR 1.5, 99% CI 1.3–1.6; OR 1.9, 99% CI 1.6–2.2), with the risks increasing for obese classes II and III. Women in obese class III were at increased risk of preterm delivery (OR 1.6, 99% CI 1.1–2.5), stillbirth (OR 3.0, 99% CI 1.0–9.3), postnatal stay > 5 days (OR 2.1, 99% CI 1.5–3.1), and infant requiring admission to a neonatal unit (OR 1.6, 99% CI 1.0–2.6).

Conclusions

By categorising women into overweight and obesity subclassifications (classes I –III), this study clearly demonstrates an increasing risk of adverse outcomes across BMI categories, with women who are overweight also at significant risk.
Progression of chronic kidney disease in a multi‐ethnic community cohort of patients with diabetes mellitus
Authors: Dreyer G. , Hull S. , Mathur R. , Chesser A. , Yaqoob M. M.
Published: March 2013

Aims

Ethnicity is a risk factor for the prevalence of severe chronic kidney disease among patients with diabetes. We studied the effect of ethnicity on progression of chronic kidney disease in people with diabetes managed in community settings.

Methods

A 5‐year retrospective, community‐based cohort study of 3855 people with diabetes mellitus of white, black or South Asian ethnicity with an estimated glomerular filtration rate of < 60 ml min−1 1.73 m−2 was undertaken. From 135 general practices in east London, all cases with at least 3 years clinical data were included. Using repeated‐measures analysis, the annual decline in estimated glomerular filtration rate was calculated. Comparisons between the rate of decline in the three main ethnic groups, with and without proteinuria at baseline, were made.

Results

The annual adjusted decline in estimated glomerular filtration rate for this cohort was 0.85 ml min−1 1.73 m−2. The rate of chronic kidney disease progression was significantly greater in South Asian groups (–1.01 ml min−1 1.73 m−2) compared with white groups (–0.70 ml min−1 1.73 m−2) (P = 0.001). For those with proteinuria at baseline, the annual decline was greater at 2.05 ml min−1 1.73 m−2, with both South Asian and black groups having a significantly faster rate of decline than white groups.

Conclusions

For patients with diabetes and chronic kidney disease managed in primary care, the annual decline of renal function is less than previously thought and approximates the age‐related annual decline of 1 ml min−1 1.73 m−2. Patients with proteinuria and those of South Asian and Black ethnicity need additional monitoring as they are at greater risk of rapid chronic kidney disease progression.
Relative contributions of insulin resistance and β‐cell dysfunction to the development of Type 2 diabetes in Koreans
Authors: Kim C.‐H. , Kim H.‐K. , Kim E. H. , Bae S. J. , Park J.‐Y.
Published: March 2013

Aims

Controversies still exist regarding the relative contributions of insulin resistance and β‐cell dysfunction to the pathogenesis of Type 2 diabetes in different populations. We examined the associations of baseline insulin resistance and β‐cell function indices with the development of Type 2 diabetes in Koreans.

Methods

We analysed the clinical and laboratory data of 17 878 Korean adults (age 20–79 years) who underwent routine medical examinations with a median interval of 3.5 years (range 2.5–4.7 years). Using the homeostasis model assessment, insulin resistance (HOMA‐IR) and β‐cell function (HOMA‐%B) indices at baseline were assessed.

Results

Those who developed diabetes (n = 732, 4.1%) had significantly higher fasting serum insulin level (53.4 ± 31.2 vs. 41.4 ± 23.4 pmol/l) and HOMA‐IR (2.38 ± 1.45 vs. 1.65 ± 1.02) and lower HOMA‐%B (74 ± 47 vs. 85 ± 48) at baseline (P < 0.001 for all). Both high HOMA‐IR and low HOMA‐%B were independently associated with an increased odds ratio of incident Type 2 diabetes. Among the participants who developed diabetes, 29% demonstrated predominant β‐cell dysfunction (HOMA‐%B < 25th percentile) and 51% had predominant insulin resistance (HOMA‐IR > 75th percentile). When we divided the participants according to the median BMI of the whole population (23.7 kg/m2), 49% of participants in the low BMI group demonstrated predominant β‐cell dysfunction and 26% had predominant insulin resistance, whilst 21% in the high BMI group demonstrated mainly β‐cell dysfunction and 60% had mainly insulin resistance.

Conclusions

In individuals with low BMI, β‐cell dysfunction is the predominant defect, whereas insulin resistance is the predominant pathogenetic factor in individuals with high BMI in the development of Type 2 diabetes in Koreans.
Comparing the Extent and Permanence of Headwater Streams From Two Field Surveys to Values From Hydrographic Databases and Maps
Authors: Fritz Ken M. , Hagenbuch Elisabeth , D'Amico Ellen , Reif Molly , Wigington Parker J. , Leibowitz Scott G. , Comeleo Randy L. , Ebersole Joseph L. , Nadeau Tracie‐Lynn
Published: March 2013

Supreme Court cases have questioned if jurisdiction under the Clean Water Act extends to water bodies such as streams without year‐round flow. Headwater streams are central to this issue because many periodically dry, and because little is known about their influence on navigable waters. An accurate account of the extent and flow permanence of headwater streams is critical to estimating downstream contributions. We compared the extent and permanence of headwater streams from two field surveys with values from databases and maps. The first used data from 29 headwater streams in nine U.S. forests, whereas the second had data from 178 headwater streams in Oregon. Synthetic networks developed from the nine‐forest survey indicated that 33 to 93% of the channel lacked year‐round flow. Seven of the nine forests were predicted to have >200% more channel length than portrayed in the high‐resolution National Hydrography Dataset (NHD). The NHD and topographic map classifications of permanence agreed with ~50% of the field determinations across ~300 headwater sites. Classification agreement with the field determinations generally increased with increasing resolution. However, the flow classification on soil maps only agreed with ~30% of the field determination despite depicting greater channel extent than other maps. Maps that include streams regardless of permanence and size will aid regulatory decisions and are fundamental to improving water quality monitoring and models.
TMDL Balance: A Model for Coastal Water Pollutant Loadings
Authors: Johnson Stephanie L. , Maidment David R. , Kirisits Mary J.
Published: March 2013

Bacterial contamination accounts for more than 60% of the impairments included on the 2008 Texas 303(d) List. Many of these bacterial impairments are along the Texas Gulf Coast because coastal waters often are regulated for oyster harvesting, which have strict water quality standards. Under the Clean Water Act, each one of these impaired waterbodies requires a total maximum daily load (TMDL) study to be performed. A recent, statewide study recommended the development and application of simple modeling approaches to address the majority of Texas's bacteria TMDLs, including “… simple load duration curve, GIS [geographic information systems], and/or mass balance models.” We developed the TMDL Balance model in response to this recommendation. TMDL Balance is a steady state, mass balance, GIS‐based model for simulating pollutant loads and concentrations in coastal systems. The model uses plug‐flow reactor and continuously‐stirred tank reactor equations to route spatially distributed point and nonpoint source loads through a watershed via overland flow, non‐tidal flow, and tidal flow, decaying the loads via first‐order kinetics. In this paper, we explain the development of the watershed loading portion of the TMDL Balance model, demonstrating the methodology through a case study: computing bacterial loads in the Copano Bay watershed of southeast Texas. The application highlights an example of distributing bacterial sources spatially based on land use data.
Road User Fees Instead of Fuel Taxes: The Quest for Political Acceptability
Authors: Duncan Denvil , Graham John
Published: March 2013

In light of recent regulatory changes in federal fuel economy standards for cars and trucks, the consensus forecast is that motor fuel taxes will not be an adequate source of dedicated funding for roadway maintenance and construction. This article accepts the notion that mileage fees are a promising replacement for the fuel tax and considers steps that might be taken to enhance the political acceptability of such a reform. The authors argue that simple, low‐tech ways of implementing mileage fees are possible in the near term and should be complemented by a well‐developed audit mechanism. Current trends in the automotive and auto insurance industries as well as social media are likely to reduce opposition to more technologically advanced mileage taxes in the long run.
Synchrotron Radiation Study on Alloy 617 and Alloy 230 for VHTR Application
Authors: Mo Kun , Tung Hsiao-Ming , Almer Jonathon , Li Meimei , Chen Xiang , Chen Weiying , Hansen Jon B. , Stubbins James F.
Published: March 2013

High-energy synchrotron radiation has proven to be a powerful technique for investigating fundamental deformation processes for various materials, particularly metals and alloys. In this study, high-energy synchrotron X-ray diffraction (XRD) was used to evaluate Alloy 617 and Alloy 230, both of which are top candidate structural materials for the very-high-temperature reactor (VHTR). Uniaxial tensile experiments using in-situ high-energy X-ray exposure showed the substantial advantages of this synchrotron technique. First, the small volume fractions of carbides, e.g., ∼6% of M6C in Alloy 230, which are difficult to observe using laboratory-based X-ray machines or neutron scattering facilities, were successfully examined using high-energy X-ray diffraction. Second, the loading processes of the austenitic matrix and carbides were separately studied by analyzing their respective lattice strain evolutions. In the present study, the focus was placed on Alloy 230. Although the Bragg reflections from the γ matrix behave differently, the lattice strain measured from these reflections responds linearly to external applied stress. In contrast, the lattice strain evolution for carbides is more complicated. During the transition from the elastic to the plastic regime, carbide particles experience a dramatic loading process, and their internal stress rapidly reaches the maximum value that can be withstood. The internal stress for the particles then decreases slowly with increasing applied stress. This indicates a continued particle fracture process during plastic deformations of the γ matrix. The study showed that high-energy synchrotron X-ray radiation, as a nondestructive technique for in-situ measurement, can be applied to ongoing material research for nuclear applications.
Incorporation of Friction Coefficient in the Design Equations for Elevated Temperature Tanks
Authors: Sathyanarayanan Sridhar , Adluri Seshu M. R.
Published: March 2013

Storage tanks operating at elevated temperatures (200 °F to 500 °F) need to consider stresses due to thermal expansions and restraints, due to the tank shell and bottom plate interactions and operating conditions in addition to the design requirements for ambient temperature tanks. Appendix M of API Standard 650 provides additional requirements and guidelines for the design of tanks operating at elevated temperatures. These are based on Karcher's method which gives a simplified procedure for determining the stresses (strain range) in the tank wall and bottom plate. A factor named “C” is used for defining the ratio of actual expansion against free expansion of the tank. Such partial expansion causes significant thermal stresses. API uses these stresses to estimate the low cycle fatigue life of the tanks. At present, a range of C values (0.25–1.0) is allowed by API without clear guidelines for selecting a suitable value. In the absence of such guidelines, a set value (like 0.85) is being used irrespective of the tank dimensions and temperature change. The restraint against free expansion is mainly a result of the friction between bottom plate, the foundation medium and the ring wall (if present). We can estimate the C factor by relating it to the friction coefficient. This is explored in the present study. This paper evaluates the current procedure and suggests an alternate method by incorporating the friction coefficient directly in the stress equations, instead of the C-factor. Use of friction coefficient provides an improved basis for selecting C and avoids some of the difficulties.