bluuebunny/crossref_metadata_2025 huggingface dataset:
PEEC antenna modeling of rectangular spiral inductors for RFID systems
Authors: Scholz Peter , Ackermann Wolfgang , Weiland Thomas
Published: December 2010

Purpose

The purpose of this paper is to offer a fast and accurate simulation method for printed spiral radio frequency identification coils and to extract the parameters of an equivalent resonance circuit.

Design/methodology/approach

The frequency‐dependent port impedance of a rectangular spiral multi‐turn antenna is simulated with the non‐retarded partial element equivalent circuit (PEEC) method. The discretization settings needed for an accurate modeling of skin and proximity effects at medium frequencies as well as parasitic capacitances are discussed. Two different PEEC approaches are used, a magneto‐quasi‐static (resistive and inductive cells) model and a non‐retarded (capacitive cells included) model in order to extract a reduced equivalent resonance circuit which is beneficial to describe the inductive coupling to further inductors via the transformer concept.

Findings

With optimized mesh settings, the extremely fast simulation can be carried out just in seconds whereas the results compared to a computationally much more expensive CST Microwave Studio® reference solution as well as an analytical direct current solution show errors of only about a few percent.

Research limitations/implications

The methodology is limited to frequencies up to the first self‐resonant frequency of the coil. In addition, piecewise‐homogeneous materials are implied.

Originality/value

Specialized mesh settings allow for a very fast and accurate simulation of rectangular spiral inductors. A method for the parameter extraction of a resonance circuit is proposed by evaluating two different PEEC models.
An integral meshless‐based approach in electromagnetic scattering
Authors: Nicomedes Williams L. , Mesquita Renato C. , Moreira Fernando J.S.
Published: December 2010

Purpose

The purpose of this paper is to solve the electromagnetic scattering problem through a new integral‐based approach that uses the moving least squares (MLS) meshless method to generate its shape functions.

Design/methodology/approach

The electric field integral equation and its magnetic counterpart (MFIE) are discretized via special shape functions built numerically through the MLS procedure. This approach is applied to the particular problem concerning the scattering of a TM plane wave by an infinite conductor cylinder. An error norm is established in order to verify the quality of the obtained results.

Findings

Results show that the discretization process which employs MLS shape functions presents very good precision and fast convergence to the solution, when compared to results provided by another numerical method, the method of moments.

Originality/value

MLS shape functions occur in meshless methods intended to solve problems based on differential formulation. This paper shows that these shape functions can also be applied successfully to problems coming from an integral formulation.
A posteriori iron loss computation with a vector hysteresis model
Authors: Belahcen A. , Dlala E. , Fonteyn K. , Belkasim M.
Published: December 2010

Purpose

The purpose of this paper is to find out how to model iron losses in electrical machines accurately and efficiently.

Design/methodology/approach

The starting point was a previously developed vector hysteresis model that was designed and incorporated into the 2D time‐stepping finite‐element (FE) simulation of induction machines. The developed approach here is a decoupling between the vector hysteresis model and the 2D FE model of the machine. The huge time consumption of the incorporated hysteresis model required some new approach to make the model computationally efficient. This is dealt with through an a posteriori use of the vector hysteresis model.

Findings

In this research, it was found that the vector hysteresis model, although used in an a posteriori scheme is able to accurately predict the iron losses as far as these losses are small enough not to affect the other operation characteristics of the machine.

Research limitations/implications

The research methods reported in this paper deal mainly with induction machines. The methods should be applied for transient operations of the induction machines as well as for other types of machines. The fact that the iron losses do not affect very much the operation characteristics of the machine is based on the fact that the air gap field plays a major role in these machines. The method cannot be applied to other magnetic devices where the iron losses are the main loss component.

Originality/value

The paper is of practical value for designers of electrical machines, who use FE programs. The methods presented here allow them to use a different FE package to simulate the machine and own routines (based on the presented methods) to predict the iron losses without loss of accuracy and in a reasonably short time.
A robust optimization based on adjoint variable method
Authors: Maruyama Takayuki , Watanabe Kota , Igarashi Hajime
Published: December 2010

Purpose

The purpose of this paper is to present a new method to obtain robust solutions to electromagnetic optimization problems, solved with evolutional algorithms, which are insensitive to changes in design parameters such as spatial size, positioning and material constant.

Design/methodology/approach

Adjoint variable method is employed to evaluate the sensitivity of individuals in evolutional processes.

Findings

It is shown in the numerical examples, where the present method is applied to optimization of a superconducting energy storage system and C‐shape magnet, that robust solutions are actually obtained which are insensitive to deviations in spatial sizes.

Originality/value

Unlike usual optimization methods, the present method takes into account deviation in the design parameters due to production errors and long‐term changes. Moreover, the present method is limited to about twice the computational cost of non‐robust optimization methods.
A numerical evaluation of electromagnetic fields exposure on real human body models until 100 kHz
Authors: Dughiero F. , Forzan M. , Sieni E.
Published: December 2010

Purpose

The purpose of this paper is to describe how numerical models of human body have been applied for the evaluation of current density induced by strong magnetic field, to verify the respect of the basic restriction proposed by International Committee Non Ionizing Radiation Protection (ICNIRP) guidelines.

Design/methodology/approach

Finite element method has been used in order to compute the induced current density in a suitable human body model and a simplified model – a homogeneous cylinder – due to a time‐varying magnetic field.

Findings

In the practical case of a resistance welding equipment, the implemented computational technique has been used in order to evaluate both the magnetic flux density and the induced current density in different tissues. Their values have been also compared with the ones obtained in a homogeneous cylinder.

Practical implications

The proposed method can be used in order to evaluate the compliance of the magnetic field produced by resistance welding equipments with ICNIRP limits.

Originality/value

A realistic model of human body has been used. In the paper, the difference on magnetic flux density and corresponding current density values is pointed out for various source positions using a heterogeneous tetrahedral human body model.
A novel circuit model of a proton exchange membrane fuel cell
Authors: Guarnieri Massimo , Moro Federico
Published: December 2010

Purpose

The purpose of this paper is to simulate passive proton exchange membrane fuel cells (PEMFCs) for portable electronic devices by means of a non‐linear lumped circuit based on electrical, mass transfer and electro‐kinetic equations.

Design/methodology/approach

Electrical, mass transfer and electro‐kinetic equations are combined in order to derive a non‐linear lumped circuit. The dynamic circuit model is tested in realistic operating conditions.

Findings

An original equivalent circuit model for simulating the transient behavior of passive PEMFCs is proposed. The PEMFC is represented as a non‐linear equivalent circuit with controlled lumped parameters depending on pressure, temperature, hydration, and system capacity.

Research limitations/implications

Lumped parameters are synthesized assuming a one‐dimensional fuel cell model since layer thicknesses are much smaller than other dimensions. Heat generation and transfer are not modeled even though lumped parameters depend on temperature.

Practical implications

The proposed circuit model can be implemented directly in circuit simulators for designing power management units needed to interface small‐passive PEMFCs and portable electronics such as PDAs, laptops, or mobile phones.

Originality/value

The fuel cell is represented as a non‐linear controlled generator whose parameters are derived directly from multiphysics equations rather than empirical relationships. The dynamic behaviour of PEMFCs can be simulated on completely different times scales, i.e. during transients or during the discharge phase.
Finite‐element analysis of a shielded pulsed‐current induction heater
Authors: Sabariego Ruth V. , Sergeant Peter , Gyselinck Johan , Dular Patrick , Dupré Luc , Geuzaine Christophe
Published: December 2010

Purpose

The aim of this paper is the experimental validation of an original time‐domain thin‐shell formulation. The numerical results of a three‐dimensional thin‐shell model are compared with the measurements performed on a heating device at different working frequencies.

Design/methodology/approach

A time‐domain extension of the classical frequency‐domain thin‐shell approach is used for the finite‐element analysis of a shielded pulse‐current induction heater. The time‐domain interface conditions at the shell surface are expressed in terms of the average flux density vector in the shell, as well as in terms of a limited number of higher‐order components.

Findings

A very good agreement between measurements and simulations is observed. A clear advantage of the proposed thin‐shell approach is that the mesh of the computation domain does not depend on the working frequency anymore. It provides a good compromise between computational cost and accuracy. Indeed, adding a sufficient number of induction components, a very high accuracy can be achieved.

Originality/value

The method is based on the coupling of a time‐domain 1D thin‐shell model with a magnetic vector potential formulation via the surface integral term. A limited number of additional unknowns for the magnetic flux density are incorporated on the shell boundary.
Virtual positioning and shaping of source fields for ECT of tubes
Authors: Ferraioli Fabrizio , Formisano Alessandro , Martone Raffaele , Iacotucci Francesco
Published: December 2010

Purpose

The purpose of this paper is to present a new approach to drive the excitation field sources in the eddy current testing (ECT) of tubular conductive structures.

Design/methodology/approach

The magnetic field used for ECT is generated by pairs of counter‐series connected coils, driven by AC currents. The phase and amplitude of the currents is electronically controlled in order to shape the primary field map, allowing circumferential sweeps until the presence of defects is detected, and then “focusing” the field on the defective section of the tube, increasing in this way the sensibility of the ECT probes in the targeted area, in order to determine with higher precision, the position, and the shape of the defect.

Findings

If suitably designed, the field measurement system allows to enable/disable a number of probes to enhance the resolution in the defect area while keeping low the number of required data channels.

Research limitations/implications

The analyzed geometry is limited to circular‐shaped tubes, of infinite extent. Future work should be on the extension of the methodology to general shapes, and to finite length cylinders.

Practical implications

The proposed method allows to enhance resolution in ECT of tubes at the end of production lines, guaranteeing a first, simple yet effective quality assessment of tubes in industrial environments.

Originality/value

The paper presents a new technique to test conductive tubes using fixed excitation system, but allowing to focus magnetic field in defective regions. The method could be helpful for industrial diagnostics.
Adaptation in coupled problems
Authors: Vokas Christos , Kasper Manfred
Published: December 2010

Purpose

The purpose of this paper is to address the formulation, implementation, and adaptation of closely coupled multi‐physics problems withh‐ andp‐adaptive finite element methods. A general formulation is chosen allowing for coupled problems of various types. Adaptation algorithms forh‐ andp‐refinement are given.

Design/methodology/approach

A generic system of second‐order differential equations is used, where the field of each individual problem is represented as an entry in the list of field variables. Specific problems are implemented by mapping material coefficients to the coefficients of the generic form. An example with four natures is investigated with close coupling between electric, mechanical and thermal fields.h‐ andp‐refinement using a single mesh is considered, where the element order may differ for individual fields.

Findings

In coupled problems, the error in each single field is affected by approximation properties of all other field quantities. In order to allow for optimal convergence order in the number of degrees of freedom, the error contributions of all fields have to be considered. Separate error estimation in each field is needed especially inh‐adaptation on a single mesh. Energy coupling coefficients were introduced to derive an adaptation criterion. Convergence analysis ofh‐ andp‐adaptation proves the feasibility of the approach.

Originality/value

Piezopyroelectricity considers thermal effects in high‐frequency piezoelectric materials, which is a coupled problem of four natures. The paper introduces an adaptation criterion for such complicated coupled problems and proves feasibility.
Comparison of pull‐in voltages in MEMS using 3D FEM and analytical approaches
Authors: Bölöni Francisc , Benabou Abdelkader , Tounzi Abdelmounaïm
Published: December 2010

Purpose

Electrostatic microelectromechanical systems are characterized by the pull‐in instability, associated to a pull‐in voltage. A good design requires an accurate model of this pull‐in phenomenon. The purpose of this paper is to present two approaches to building finite element method (FEM) based models.

Design/methodology/approach

Closed form expressions for the computation of the pull‐in voltage, can provide fast results within reliable accuracy, except when treating cases of extreme fringing fields. FEM‐based models come handy when high accuracy is needed. In the first model presented in this paper, the FEM is used to solve the electrostatic problem, while the mechanical problem is solved using a simplified Euler‐Bernoulli beam equation. The second model is a pure FEM model coupling the electrostatic and mechanical problems iteratively through the electrical force. Results for both scalar and vector potential formulations for the FEM models are presented.

Findings

In this paper a comparative study of simple pull‐in structures is presented, between analytical and 3D FEM‐based models. A comparison with analytical models and experimental results is also realized.

Research limitations/implications

The coupling between the electrostatic and mechanical problem in the presented approaches, is iterative. Therefore, to improve the accuracy of the presented model, a strong coupling is needed.

Originality/value

In the presented FEM‐analytical model, the electrostatic problem is solved in both, scalar and vector electric potential formulations. This allows defining an upper and a lower limit for the electrostatic force and consequently for the pull‐in voltage.
Selecting and implementing a patron‐driven resource reservation system
Authors: Sallans Andrew , Soule Kathryn , Gilbert Joseph
Published: December 2010

Purpose

The purpose of this paper is to describe criteria for selecting and processes for implementing a self‐service online resource reservation using the University of Virginia (U.Va.) Library as a case study.

Design/methodology/approach

The paper chronicles the identified needs, selection criteria, and deployment strategy undertaken by a U.Va. Library task force in early to mid‐2010 along with the unexpected pitfalls and policy implications uncovered by the process.

Findings

The U.Va. Library selected and rolled out a product meeting a variety of public service needs, EMS Enterprise, in the summer/fall of 2010, with lessons learned about the intricacies of IT infrastructure, public service policies and procedures, and the varied resource reservation needs of the library's libraries and labs.

Originality/value

The paper demonstrates how the addition of a self‐scheduling reservation system has helped fill a long‐awaited need and adds value to the U.Va. Library's Services.
Terminology and trend watching via ResearchRaven
Authors: Leman Hope
Published: December 2010

Purpose – This paper aims to discuss the importance and value to librarians of keeping up with new trends and terms occurring in the scholarly literature before they become commonplace. The paper makes several arguments as to why doing so helps librarians remain relevant to patrons in an increasingly challenging library environment. Also suggested are ways that librarians can create web services that leverage the knowledge they gain about the new terms with which they have gained some expertise. Design/methodology/approach – This paper contains a discussion of the author's own experience in developing the free online web service ResearchRaven, and notes the rise of certain new terms (e.g. epigenetics) in the health sciences. The new terms' appearance in calls for papers for meetings, in calls for papers for publication and in grant funding announcements signaled that the increasing use of single words or short phrases in such venues offers opportunities for librarians to develop expertise in the subject area – and to develop web applications growing out of such expertise. Findings – This paper provides empirical insights into reasons why librarians need to keep to keep up with the rise and incidence of new scholarly terms and coinages, long before they appear in the scholarly literature and in such databases as PubMed. The paper also details how librarians can use the e‐mail alerts and RSS feeds of ResearchRaven to keep informed, and suggests avenues for developing comparable web services to showcase their own libraries and existing services (e.g. institutional repositories). Originality/value – This paper fulfills a need to encourage librarians to track the use of new terms in the health sciences and in scholarship generally, to gain familiarity with such terms, to follow with erudition and acumen the rise of nascent fields and the interactions among many disciplines, to spot opportunities to develop web services and applications to serve those new communities, and to convey to existing disciplines news of developments that might be of interest to them, thereby rendering their libraries ever more innovative in practice while at the same time adding value for patrons.
Link analysis and impact of top universities of Islamic world on the world wide web
Authors: Didegah Fereshteh , Goltaji Marzieh
Published: December 2010

Purpose

This purpose of this paper is to report on an analysis of linkages and impact of top universities of Islamic Countries on the web.

Design/methodology/approach

The AltaVista search engine was used to calculate universities' number of links and web impact factors.

Findings

The results revealed that half of the universities have not scored well in the indexes used by the webometrics ranking model. Among all universities, King Saud University of Saudi Arabia scored well in most indexes.

Originality/value

The paper presents a look at the functions and performance of top universities' web sites of Islamic countries.
A comparative study of two different techniques for evaluating service quality
Authors: Gupta Sumana , Nath Datta Rabindra
Published: December 2010

Purpose

The conventional methods of evaluating service quality analyze data obtained in ordinal scale that assumes scale continuum. The purpose of this paper is to compare the control boundary model with a proposed method that uses law of categorical judgment, which converts data into interval scale. In this paper, the advantages of using the law of categorical judgment over the control boundary model, a method which uses the data directly, is presented by analyzing customer response data obtained to evaluate quality of service in the Howrah Railway Station, a major railway terminal in eastern India.

Design/methodology/approach

Law of categorical judgment has been used for data conversion to interval scale and a comparative analysis is made with the results obtained from control boundary model.

Findings

The results obtained from the two techniques show that the proposed method of evaluation is more suitable to the context.

Research limitations/implications

The work is limited to the subjective evaluation of the physical and functional services of a railway station. Several other aspects like managerial, behavioral, etc. are not considered.

Originality/value

Evaluating service quality in this domain is a difficult task. The paper not only proposes a new method but also compares the results with an existing evaluation model.
A note on corporate social responsibility (CSR) in city branding and design
Authors: Kim Jai B. , Kwak Gretta , Koo Yoo R.
Published: December 2010

Purpose

By exploring the evolution of corporate social responsibility (CSR) and evaluating major frameworks of CSR provided in a wider range of early works, this paper attempts to identify key domains of CSR and propose the revised CSR framework for strategic CSR management processes. The paper provides extended insights into how the concept of strategic CSR is integrated into city branding and design and highlights and addresses the roles of CSR that are inter‐linked to city brand management in terms of sustainable value creation to meet a community's societal, political or economic objectives.

Design/methodology/approach

The overall content of this paper is concerned with theory of CSR and the fundamental logic behind city branding. The frameworks are developed based upon the historical review of theory and observation of trends in the current issues.

Findings

The paper funds that CSR is an integral framework to encompass not just principles of social responsibility, but processes of social responsiveness and outcomes of social performance as well.

Research limitations/implications

Notwithstanding a number of management literature that seeks out strategic linkages between competitive advantage, a crucial strategy concept and CSR, research concerned with the relationship between CSR and city branding is at in its infancy. There is a need to examine the essential ingredients that produce design‐driven value in the process of implementing strategic CSR into city branding. Future research, taking the difference between the firm/product and the city into account, will further investigate how city branding and design can be implemented to reflect social responsibility, notably in terms of the process and evaluation.

Originality/value

The paper not only presents the revised framework of CSR and major constituents of strategic CSR but also seeks to enlighten and establish a new connection between CSR and value creation that bring us an innovative perspective when implemented in city branding and design.
A study of the factors which influence franchisor profit structure with running royalty policy for its sustainable growth
Authors: Kwon Tae‐Woo(Mike) , Choi Kanghwa
Published: December 2010

Purpose

The purpose of this paper is to assess the conceptual relationship between the running royalty programs and the performance of a franchisee or franchisor. Thus, this paper will analyze the correlation of financial stability when the franchisor strengthens the running royalty policy at aspect of franchisor.

Design/methodology/approach

A model is presented and designed. The paper will analyze the causality which is affected by strengthening the profit structure with the running royalty program and also find out how the strengthened profit structure will affect and improve the franchisors' sustainable supports for the franchisees, service quality and service satisfactions.

Findings

Although the franchise industry is growing in Korea, the stability of business is still in doubt because the business cycle of the franchisor is shortened. This paper found the reasons why franchisors have unstable status in Korea. The main reason was the instability of profit structures for franchisors which are a burden to the franchisees which then worsen the franchisors' financial status. The biggest different from the US franchise industry was the running royalty program. So, this paper will apply the running royalty program politically to the franchise business in Korea and find out how it will affect the overall business cycle.

Originality/value

This study was limited to the Korean franchise industry and found out the factors which influence the franchisors' performance in various aspects. By analyzing with casual loop diagram, this paper found how each of the factors interact and bring out the positive feedback process. Also, it suggests a way of adopting the running royalty program into the Korean market.
Economic‐statistical design of variable sampling intervals EWMA charts under non‐normality
Authors: Xue Li , Xu Jichao , Liu Yumin
Published: December 2010

Purpose

The purpose of this paper is to investigate the economic‐statistical design of EWMA charts with variable sampling intervals (VSIs) under non‐normality to reduce the process production cycle cost and improve the statistical performance of control charts. The objective is to minimize the cost function by adjusting the control chart parameters which suffice for the statistical restriction.

Design/methodology/approach

First, using the Burr distribution to approximate various non‐normal distributions, the economic‐statistical model of the VSI EWMA charts under non‐normality can be developed. Further, the genetic algorithms will be used to search for the optimal values of parameters of the VSI EWMA charts under non‐normality. Finally, a sensitivity analysis is carried out to investigate the effect of model parameters and statistical restriction on the solution of the economic‐statistical design.

Findings

The result of sensitivity analysis shows that a large lower bound of average time to signal when the process is in control increases the control limit coefficient, no model parameter significantly affects the short sampling intervals, and so on.

Originality/value

The economic‐statistical design method proposed in this paper can improve the statistical performance of economic design of control charts and the general idea can be applied to other VSI control charts.
An empirical model to assess the influence of the government's research and development program on Korean small and medium enterprise (SME) performance
Authors: Young Park Ji , Wook Kim Soo
Published: December 2010

Purpose

The purpose of this paper is to suggest an empirical model to assess the separate effect of the government's research and development (R&D) policy program in small and medium enterprise (SME) performance.

Design/methodology/approach

The paper reviews the R&D related papers and finds out the specific aspects of the Korean R&D policy program, classifying every R&D policy program and giving them unique names such as funds, technology and human resource support. Finally, the paper provides the whole empirical model and research questions for future studies.

Findings

First, the paper suggests the research model and several questions about whether the direct government funding of R&D policy program has had an effect on SMEs' business performance. Second, the interaction of direct government R&D funding, technology and human resource support are compared. Finally, a research model is suggested with proper research methodology.

Research limitations/implications

Owing to the research purpose, the paper ends with the suggestion of an empirical model. Panel data needs to be applied to verify the suggested model.

Originality/value

There are various papers regarding the effect of R&D investment from private and public sectors, but few papers exist about the causal relationship between the government R&D policy program and SMEs' performance.
Comparison of onshore and offshore student learning experience in an economic unit of study
Authors: Havrila Inka , Zhang Christabel
Published: December 2010

University students often view economics as one of the most challenging subjects. In this paper, we explore whether the same attitude is shared by students at an offshore campus. The analysis is based on a survey of onshore and offshore students in an Australian university. The focus of the paper is on identifying similarities/differences in student attitudes towards economics, their degree of motivation, satisfaction with the content and the delivery of lectures and tutorials, major challenges, and student profile characteristics. A non‐parametric test indicates significant differences between the two cohorts, in terms of their age, enrolment status, paid work commitments, prior study of economics, their motivation and approach to studying the subject, and satisfaction with both the content and the delivery of the lectures/tutorials. The findings in this study are helpful in developing strategies for enhancing student learning in culturally diverse cohorts.
Indigenising international education in business
Authors: Ma Rhea Zane
Published: December 2010

This paper examines some of the issues associated with and the possibilities of incorporating Indigenous perspectives into courses on international business. Studies in the area of international education in business have a responsibility towards developing in management students an understanding of the international frameworks that protect the rights of Indigenous peoples. In order to develop effective business partnerships with Indigenous people students training in business schools require an understanding of business ethic, cross‐cultural and leadership skills. This paper provides a framework that can strengthen students’ abilities to develop sustainable partnerships in securing an economic future for all communities on this planet.
International textile and clothing research register
Authors: Stylios George K.
Published: December 2010

Examines the fifteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.
Plasma levels of glucagon like peptide‐1 associate with diastolic function in elderly men
Authors: Nathanson D. , Zethelius B. , Berne C. , Lind L. , Andrén B. , Ingelsson E. , Holst J. J. , Nyström T.
Published: December 2010

Diabet. Med. 28, 301–305 (2011)

Aims  Congestive heart failure is a major cause of morbidity and mortality in diabetes. Besides the glycaemic effects of glucagon‐like peptide 1 (GLP‐1) mimetics, their effects on the heart are of interest.

Methods  We aimed to investigate longitudinal relationships between plasma levels of fasting GLP‐1 (fGLP‐1), 60‐min oral glucose tolerance test‐stimulated GLP‐1 levels (60GLP‐1), and the dynamic GLP‐1 response after oral glucose tolerance test (ΔGLP‐1 = 60GLP‐1 – fGLP‐1) and incidence of hospitalized congestive heart failure, during a follow‐up time of a maximum of 9.8 years in 71‐year‐old men. We also investigated, cross‐sectionally, the association between GLP‐1 and left ventricular function as estimated by echocardiography.

Results  During the follow‐up period, 16 of 290 participants with normal glucose tolerance experienced a congestive heart failure event (rate 0.7/100 person‐years at risk), as did eight of 136 participants (rate 0.8/100 person‐years at risk) with impaired glucose tolerance and nine of 72 participants (rate 1.7/100 person‐years at risk) with Type 2 diabetes mellitus. Although GLP‐1 concentrations did not predict congestive heart failure (fGLP‐1: HR 0.98, 95% CI 0.4–2.4; 60GLP‐1: HR 1.1, 95% CI 0.4–2.6; ΔGLP‐1: HR 0.9, 95% CI 0.3–2.3), there was an association between left ventricular diastolic function (E/A ratio) and fGLP‐1 (r = 0.19, P = 0.001), 60GLP‐1 (r = 0.20, P < 0.001) and ΔGLP‐1 (r = 0.18, P = 0.004). There was a lack of differences in plasma levels of GLP‐1 between the groups with Type 2 diabetes and normal glucose tolerance.

Conclusions  There were no longitudinal associations between GLP‐1 levels and incidence of hospitalization for congestive heart failure. However, without any causality proven, GLP‐1 levels did correlate, cross‐sectionally, with left ventricular diastolic function in this cohort, suggesting that pathways including GLP‐1 might be involved in the regulation of cardiac diastolic function.
Exercise treadmill testing in patients with claudication, with and without diabetes
Authors: Mahé G. , Ouedraogo N. , Leftheriotis G. , Vielle B. , Picquet J. , Abraham P.
Published: December 2010

Diabet. Med. 28, 356–362 (2011)

Aim  To compare symptoms and walking capacities of patients with and without diabetes reporting vascular‐type claudication.

Methods  We recorded self‐reported maximal walking distance, maximal walking distance on treadmill test (3.2 km h−1, 10% slope), exercise transcutaneous oxygen pressure DROP index [limb transcutaneous oxygen pressure (TcpO2) changes from rest minus chest TcpO2 changes from rest] and symptoms on treadmill in 230 patients with diabetes and 982 patients without diabetes. Exercise‐induced proximal and distal symptoms were analysed in the perspective of underlying proximal and distal ischaemia (DROP value < negative 15 mmHg).

Results  Self‐reported maximal walking distance did not differ between groups, whereas maximal walking distance on treadmill test was lower in patients with diabetes vs. patients without diabetes (261 ± 257 and 339 ± 326 m, respectively; P < 0.05 when adjusted for potential confounders). In patients with ischaemia, the number of ischaemic areas (proximal and/or distal on right and/or left) was comparable between the two groups. Patients with diabetes had more distal ischaemia than patients without diabetes (38 vs. 29%, respectively; P < 0.01), whereas proximal ischaemia was similar between groups. The prevalence of lower‐limb exercise‐related symptoms without ischaemia was comparable between groups. There were more symptoms other than lower‐limb pain in patients with diabetes than patients without diabetes (29.6 vs. 18.3%, respectively; P < 0.01).

Conclusions  Patients with diabetes show more severe limitation on the treadmill and more non‐limb symptoms than patients without diabetes, although self‐reported walking capacity is comparable between the two groups. Using TcpO2, we confirm that patients with diabetes reporting claudication show more distal ischaemia than patients without diabetes, with no difference at the buttock level. Treadmill testing is of interest in patients with peripheral artery disease and diabetes.
Psychiatric morbidity in two low birth weight groups assessed by diagnostic interview in young adulthood
Authors: Lund Line K , Vik Torstein , Skranes Jon , Brubakk Ann‐Mari , Indredavik Marit S
Published: December 2010

Aim:  To study the prevalence and characteristics of psychiatric symptoms and disorders in young adults born with low birth weight.

Methods:  At 20 years of age 44 very low birth weight (VLBW: birth weight ≤1500 g), 55 term born small for gestational age (SGA: birth weight <10th percentile) and 75 control subjects born 1986–1988 were assessed using the interview Schedule for Affective Disorders and Schizophrenia for School‐age children and Structured Clinical Interview for DSM‐IV Personality Disorders, Children’s Global Assessment Scale and Attention deficit hyperactivity disorder (ADHD) Rating Scale IV; self‐report and parent report.

Results:  Fourteen (33%) VLBW versus six (8%) control participants had a definite psychiatric disorder: OR = 5.6 (1.9–15.9). In the term SGA group, 14 (26%) had a disorder: OR = 3.9 (1.4–11.0) vs controls. Anxiety disorders and ADHD were the most frequent diagnoses. The differences were not explained by gender, assessment age or parental socioeconomic status. ADHD Rating Scale mean scores were higher in parent reports in the VLBW group and in self‐reports in the term SGA group compared with the control group.

Conclusion:  Children born with low birth weight whether caused by preterm birth or by growth retardation at term seem to be at increased risk for psychiatric disorders as young adults.
Functional and structural analyses of N‐acylsulfonamide‐linked dinucleoside inhibitors of RNase A
Authors: Thiyagarajan Nethaji , Smith Bryan D. , Raines Ronald T. , Acharya K. Ravi
Published: December 2010

Molecular probes are useful for both studying and controlling the functions of enzymes and other proteins. The most useful probes have high affinity for their target, along with small size and resistance to degradation. Here, we report on new surrogates for nucleic acids that fulfill these criteria. Isosteres in which phosphoryl [R–O–P(O2−)–O–R′] groups are replaced with N‐acylsulfonamidyl [R–C(O)–N−–S(O2)–R′] or sulfonimidyl [R–S(O2)–N−–S(O2)–R′] groups increase the number of nonbridging oxygens from two (phosphoryl) to three (N‐acylsulfonamidyl) or four (sulfonimidyl). Six such isosteres were found to be more potent inhibitors of catalysis by bovine pancreatic RNase A than are parent compounds containing phosphoryl groups. The atomic structures of two RNase A·N‐acylsulfonamide complexes were determined at high resolution by X‐ray crystallography. The N‐acylsulfonamidyl groups were observed to form more hydrogen bonds with active site residues than did the phosphoryl groups in analogous complexes. These data encourage the further development and use of N‐acylsulfonamides and sulfonimides as antagonists of nucleic acid‐binding proteins.

Database
 Structural data for the two RNase A complexes are available in the Protein Data Bank under accession numbers 2xog and 2xoi
Molecular Indications of Protein Damage in Adenoviruses after UV Disinfection
Authors: Eischeid Anne C. , Linden Karl G.
Published: December 2010

Adenoviruses are resistant to monochromatic, low-pressure (LP) UV disinfection—but have been shown to be susceptible to inactivation by polychromatic, medium-pressure (MP) UV—when assayed using cell culture infectivity. One possible explanation for the difference between UV lamp types is that the additional UV wavelengths emitted by MP UV enable it to cause greater damage to viral proteins than LP UV. The objective of this study was to examine protein damage in adenoviruses treated with LP and MP UV. Results show that MP UV is more effective at damaging viral proteins at high UV doses, though LP UV caused some damage as well. To our knowledge, this study is the first to investigate protein damage in UV-treated adenovirus, and the overview presented here is expected to provide a basis for further, more detailed work.
Antimicrobial Resistance in GenericEscherichia coliIsolates from Wild Small Mammals Living in Swine Farm, Residential, Landfill, and Natural Environments in Southern Ontario, Canada
Authors: Allen Samantha E. , Boerlin Patrick , Janecko Nicol , Lumsden John S. , Barker Ian K. , Pearl David L. , Reid-Smith Richard J. , Jardine Claire
Published: December 2010

To assess the impacts of different types of human activity on the development of resistant bacteria in the feces of wild small mammals, we compared the prevalences and patterns of antimicrobial resistance and resistance genes in genericEscherichia coliandSalmonella entericaisolates from fecal samples collected from wild small mammals living in four environments: swine farms, residential areas, landfills, and natural habitats. Resistance to antimicrobials was observed inE. coliisolates from animals in all environments: 25/52 (48%) animals trapped at swine farms, 6/69 (9%) animals trapped in residential areas, 3/20 (15%) animals trapped at landfills, and 1/22 (5%) animals trapped in natural habitats. Animals trapped on farms were significantly more likely to carryE. coliisolates with resistance to tetracycline, ampicillin, sulfisoxazole, and streptomycin than animals trapped in residential areas. The resistance genessul2,aadA, andtet(A) were significantly more likely to be detected inE. coliisolates from animals trapped on farms than from those trapped in residential areas. ThreeS. entericaserotypes (Give, Typhimurium, and Newport) were recovered from the feces of 4/302 (1%) wild small mammals. AllSalmonellaisolates were pansusceptible. Our results show that swine farm origin is significantly associated with the presence of resistant bacteria and resistance genes in wild small mammals in southern Ontario, Canada. However, resistant fecal bacteria were found in small mammals living in all environments studied, indicating that environmental exposure to antimicrobials, antimicrobial residues, resistant bacteria, or resistance genes is widespread.
Induction of Fatty Acid Composition Modifications and Tolerance to Biocides in
Salmonella enterica
Serovar Typhimurium by Plant-Derived Terpenes
Authors: Dubois-Brissonnet Florence , Naïtali Murielle , Mafu Akier Assanta , Briandet Romain
Published: December 2010

To enhance food safety and stability, the food industry tends to use natural antimicrobials such as plant-derived compounds as an attractive alternative to chemical preservatives. Nonetheless, caution must be exercised in light of the potential for bacterial adaptation to these molecules, a phenomenon previously observed with other antimicrobials. The aim of this study was to characterize the adaptation of
Salmonella enterica
serovar Typhimurium to sublethal concentrations of four terpenes extracted from aromatic plants: thymol, carvacrol, citral, and eugenol, or combinations thereof. Bacterial adaptation in these conditions was demonstrated by changes in membrane fatty acid composition showing (i) limitation of the cyclization of unsaturated fatty acids to cyclopropane fatty acids when cells entered the stationary phase and (ii) bacterial membrane saturation. Furthermore, we demonstrated an increased cell resistance to the bactericidal activity of two biocides (peracetic acid and didecyl dimethyl ammonium bromide). The implications of membrane modifications in terms of hindering the penetration of antimicrobials through the bacterial membrane are discussed.
Characterization of a Novel β-Xylosidase, XylC, from
Thermoanaerobacterium saccharolyticum
JW/SL-YS485
Authors: Shao Weilan , Xue Yemin , Wu Ailian , Kataeva Irina , Pei Jianjun , Wu Huawei , Wiegel Juergen
Published: December 2010

The 1,914-bp open reading frame of
xylC
from
Thermoanaerobacterium saccharolyticum
JW/SL-YS485 encodes a calculated 73-kDa β-xylosidase, XylC, different from any glycosyl hydrolase in the database and representing a novel glycohydrolase family. Hydrolysis occurred under retention of the anomeric configuration, and transglycosylation occurred in the presence of alcohols as acceptors. With the use of vector pHsh, expression of XylC, the third β-xylosidase in this bacterium, increased approximately 4-fold when a loop within the translational initiation region in the mRNA was removed by site-directed mutagenesis. The increased expression of
xylC

m

is due to removal of a stem-loop structure without a change of the amino acid sequence of the heterologously expressed enzyme (XylC
rec
). When gel filtration was applied, purified XylC had molecular masses of 210 kDa and 265 kDa using native gradient gel electrophoresis. The protein consisted of 78-kDa subunits based on SDS gel electrophoresis and contained 6% carbohydrates. XylC and XylC
rec
exhibited maximum activity at 65°C and pH
65°C
6.0, a 1-h half-life at 67°C, a

K
m

for
p
-nitrophenyl-β-
d
-xyloside of 28 mM, and a
V
max
of 276 U/mg and retained 70% activity in the presence of 200 mM xylose, suggesting potential for industrial applications.
Cytosolic Localization of Acetohydroxyacid Synthase Ilv2 and Its Impact on Diacetyl Formation during Beer Fermentation
Authors: Dasari Suvarna , Kölling Ralf
Published: December 2010

Diacetyl (2,3-butanedione) imparts an unpleasant “butterscotch-like” flavor to alcoholic beverages such as beer, and therefore its concentration needs to be reduced below the sensory threshold before packaging. We examined the mechanisms that lead to highly elevated diacetyl formation in petite mutants of
Saccharomyces cerevisiae
during beer fermentations. We present evidence that elevated diacetyl formation is tightly connected to the mitochondrial import of acetohydroxyacid synthase (Ilv2), the key enzyme in the production of diacetyl. Our data suggest that accumulation of the matrix-targeted Ilv2 preprotein in the cytosol is responsible for the observed high diacetyl levels. We could show that the Ilv2 preprotein accumulates in the cytosol of petite yeasts. Furthermore, expression of an Ilv2 variant that lacks the N-terminal mitochondrial targeting sequence and thus cannot be imported into mitochondria led to highly elevated diacetyl levels comparable to a petite strain. We further show that expression of a mutant allele of the γ-subunit of the F
1
-ATPase (
ATP3-5
) could be an attractive way to reduce diacetyl formation by petite strains.
Transcriptional Analysis of a
Photorhabdus
sp. Variant Reveals Transcriptional Control of Phenotypic Variation and Multifactorial Pathogenicity in Insects
Authors: Lanois A. , Pages S. , Bourot S. , Canoy A.-S. , Givaudan A. , Gaudriault S.
Published: December 2010

Photorhabdus luminescens
lives in a mutualistic association with entomopathogenic nematodes and is pathogenic for insects. Variants of
Photorhabdus
frequently arise irreversibly and are studied because they have altered phenotypic traits that are potentially important for the host interaction. VAR* is a colonial and phenotypic variant displaying delayed pathogenicity when directly injected into the insect,
Spodoptera littoralis
. In this study, we evaluated the role of transcriptomic modulation in determining the phenotypic variation and delayed pathogenicity of VAR* with respect to the corresponding wild-type form, TT01α. A
P. luminescens
microarray identified 148 genes as differentially transcribed between VAR* and TT01α. The net regulator status of VAR* was found to be significantly modified. We also observed in VAR* a decrease in the transcription of genes supporting certain phenotypic traits, such as pigmentation, crystalline inclusion, antibiosis, and protease and lipase activities. Three genes encoding insecticidal toxins (
pit
and
pirB
) or putative insecticidal toxins (
xnp2
) were less transcribed in VAR* than in the TT01α. The overexpression of these genes was not sufficient to restore the virulence of VAR* to the levels of ΤΤ01α, which suggests that the lower virulence of VAR* does not result from impaired toxemia in insects. Three loci involved in oxidative stress responses (
sodA
,
katE
, and the
hca
operon) were found to be downregulated in VAR*. This is consistent with the greater sensitivity of VAR* to H
2
O
2
and may account for the impaired bacteremia in the hemolymph of
S. littoralis
larvae observed with VAR*. In conclusion, we demonstrate here that some phenotypic traits of VAR* are regulated transcriptionally and highlight the multifactorial nature of pathogenicity in insects.