bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of the Armstrong friction model to study dynamic transient response in workpiece-fixture systems
Authors: Motlagh H E , Hamedi M , Nikkhah-Bahramy M
Published: April 2011

Dynamic interactions in the tool-workpiece and workpiece-fixture systems significantly impinge on the quality of machined workpieces. The dynamics of these systems are determined by many factors including fixture layout and frictional contact at the workpiece-fixture interface. In this paper, a multi-body flexible model of a frictional workpiece-fixture system is developed. A combination of the bristles concept with a modified version of the Armstrong friction model is employed to study dynamic interactions in the system. This analytical model enables the study of presliding and microsliding in the contact region along the transient dynamic response of the workpiece-fixture through an impact hammer test. Studying the behaviour of the bristles for various clamping forces indicates that the frictional damping decreases at higher clamping forces, which is due to increase in difference between the phase angles of oscillating bristles representing surface asperities. The model is validated by reproducing published experimental results. The presented modelling and solution methodology assists in detailed investigation of the contact region behaviour and can lead to optimal design of fixture elements specifically for delicate work parts and microelectromechanical systems (MEMS). The observed phase angle phenomenon can be utilized for determination of the optimal dynamic clamping forces. The simulated displacement history obtained via the presented modelling is very suitable for using to improve machining stability by extracting chatter stability lobes.
The impact of uncertainty on product introduction in dispersed environments
Authors: Schofield M E , Gregory M
Published: April 2011

This research addresses product introduction dispersed across locations and companies. A semiconductor design licensor that introduces products in a range of environments was studied: in some environments the subcomponent architectures of competitor products differ widely, while in others all competitor products have the same subcomponents. The approach adopted involved multiple detailed interviews covering the full range of participants in the product development processes from designers through project managers to directors. Reporting from these multiple informants was captured using a novel mapping approach that allowed participants to develop interactively their understanding of informal as well as formal processes at work within the company.

It was found that the degree of architectural uncertainty is a major determinant of feasible organization structures for product introduction. It was also found that ‘microproduct’ architecture offers considerable freedom in the opportunities for dispersion of project activities. The degree of formality and structure in design technologies and their link to highly characterized production processes was identified as a key factor of this industry sector.

The implications of these findings include the probability that (a) where design technologies can simulate product performance, dispersed teams with high priority can resolve architectural uncertainties; (b) a cross-functional team may not resolve architectural uncertainty as well as autonomous teams focused on subproducts (microproducts); (c) early entrants may benefit by allowing business units to adopt diverse approaches to product introduction, since architectural uncertainty may vary between products at different stages of their lives. This suggests that small high-technology companies may find it easier to expand into new geographies and product lines than was previously believed.

Further work is necessary to make more confident statements about the linkage between product environment and team organization, but the ideas of architectural uncertainty and microproduct team organization may be of immediate interest to companies of all sizes when seeking to select appropriate product introduction processes and organization.
An evaluation of the TI2 manufacturing system for the machining of airframe subassemblies
Authors: Webb P , Eastwood S J
Published: April 2011

The commercial aircraft manufacturing industry is continually seeking new techniques for the automation of manufacturing and assembly tasks in the construction of aero-structures. The application of automation is limited by the size and compliance of the structures, the low manufacturing volumes and the inherent dimensional variability between assemblies. New automated systems based on the use of advanced control systems and non-contact metrology are now beginning to overcome some of these problems and the use of automation is becoming more viable. The TI2 system is one such system and this paper presents the results obtained from its application to the machining of a representative airframe subassembly. Real results are presented along with a discussion of some of the problems that may be encountered when using such a system.
Machining-induced surface hardening due to large wear land
Authors: Mahajan V , Chou Y K
Published: April 2011

This study experimentally investigated the attainable hardness and hardened depth at the part surfaces in steel machining with large tool wear, 1-2mm flank wear-land width. Hot-rolled AISI 4340 steel bars were turned on a lathe using ceramic inserts with machining forces monitored. Process parameter effects on the depths of the phase-transformed layers and hardened layers were studied with cutting forces and part surface roughness measured and analysed. The phase transformation depth (PTD) and hardened depth generally increase with increasing tool wear, cutting speed, and feed rate; however, they decrease or level off when further increasing the parameters. The maximum hardened depth, about 100 μm at a Knoop hardness of 450 HK500, has been repeatedly obtained at 1.65 mm flank wear land, 3 m/s cutting speed and 0.025 mm/rev feed rate. It is plausible that machining under aggressive conditions, i.e. a greater amount of tool wear, may be employed for surface hardening of some steel components.

The analysis of variance (ANOVA) method was also applied to identify statistically significant factors and interactions between the factors. The ANOVA results of the PTD indicate that cutting speed, flank wear-land width, and feed rate, in that order, are all significant factors. In addition, there is a major interaction between feed rate and cutting speed to the PTD results. Furthermore, the cutting force results imply a strong correlation between the radial cutting forces and the PTD.
Mould pressure control in rotational moulding
Authors: Crawford R J , Spence A G , Cramez M C , Oliveira M J
Published: April 2011

The technology of the rotational moulding of plastics has improved dramatically in recent years due to the recognition that measuring the temperature inside the mould is fundamental to process control. The next major advance will be made when the benefits of controlling the pressure inside the mould are fully utilized. A drawback of the rotational moulding process has always been the surface pinholes and internal bubbles that occur in the moulded part. These occur because, as the powder particles melt and coalesce, they trap pockets of air and it takes a considerable time for these to disappear.

It is known that factors such as the viscosity of the polymer melt, the shape of the powder particles, the particle size and size distribution, the mould release agent and the metal used for the mould all affect the pinholing problem. However, the major factor that influences pinhole removal is mould pressure. If pressure is applied at a strategic point in the heating cycle, it can force trapped air out of the melted plastic. Indeed the use of mould pressurization can offer additional benefits such as cycle time reduction and significant improvements in the mechanical properties of the moulded part. However, few moulders make any attempt to monitor or control the mould pressure, mainly because its effect is not understood.

This paper explains why mould pressure control throughout the moulding cycle is crucial to the rotational moulding industry in terms of, firstly, achieving good part quality and, secondly, reducing cycle times. It is also suggested that a fundamental change from passive venting to active venting of the mould is an important development that must occur in this industry.
Finite element modelling approaches to the accurate dimensional prediction for a cold-forged part
Authors: Lee Y S , Kwon Y N , Lee J H , Ishikawa T
Published: April 2011

The dimensions of the cold-forged part turn out to be larger than those of the die cavity, since a die can be deformed more elastically than a forged material. To predict precisely the dimensions of the forged part and to determine the die dimensions for net-shape components, dimensional evolution of the die and workpiece should be performed carefully; therefore, finite element methods (FEMs) have been proposed to predict more accurately the dimensions of the forged product in closed-die upsetting. Together with finite element analysis (FEA), direct measurements of strains from the die during forging were attempted in order to validate the simulated results.

In the present study, the dimensional changes of the die and workpiece due to elastic and thermal effects were investigated thoroughly by separating a single forging step into three stages: loading, unloading and ejecting stages. As a result, FEM results could predict the part dimensions to within a range of 10 μm. In particular, the characteristics of the unloading and ejecting stages have been discussed in conjunction with the elastic recovery of forged parts. When temperature changes due to the deformation heat were additionally considered in the finite element models, the predicted dimensions more closely coincided with the experimental results. Since the elastic modulus of workpiece materials has a great influence on the final forged product, the effects of the elastic modulus for the workpiece were deliberately investigated, and then the modelling technique applicable to the three-dimensional forged part was proposed in order to increase the simulation efficiency.

The dimensional differences between the die and forged part were compared quantitatively in the experimental and FEA. The result was used for machining a modified die. The FEM results using the modified die validated that the dimensional difference between the die and forged part had a linear relationship.
Machine tool thermal error reduction—an appraisal
Authors: Postlethwaite S R , Allen J P , Ford D G
Published: April 2011

It has been shown that machine tool thermal distortion can account for 75 per cent of the total machining error. As a result there has been a great deal of interest in techniques for reducing thermal errors. The approaches taken to thermal error reduction can be divided into two broad categories of reducing structural temperature change and reducing the effect of structural temperature change. This paper discusses a number of representative examples of applied thermal error reduction techniques that utilize machine design and compensation. The paper appraises these techniques, highlighting their relative merits. Based on this appraisal the requirements for a general thermal error reduction technique are established.
A hypothesis on a wavelength fixing mechanism of rail corrugation
Authors: Manabe K
Published: April 2011

The mechanism of rail corrugation is analysed by a mathematical model in which a rail is represented as an infinite beam and a bogie as two point masses. The contact forces and the rate of increase in corrugation amplitude are calculated. The result shows that high growing rates occur in some velocity-wavelength regions, which nearly agree with conditions for generation of real line corrugation. It is considered that, in a rail excited at two points, the deformation wave is the result of the interference between those from the two points, and the wave is completely cancelled at the two exciting points under some conditions. This interference is considered as a fundamental mechanism of corrugation.
European freight vehicle running gear: Today's position and future demands
Authors: Hecht M
Published: April 2011

The running gear of most of the rail freight vehicles in operation today tends to be built to very old designs. The running gear for new freight rolling stock and, in particular, new types of bogie must have significantly improved performance if they are to satisfy the demands of all the stakeholders associated with the railways. Improved performance in this context means reduced inspection time and brake manipulation time in marshalling yards, lower weight, lower noise emissions and lower lateral track forces. All this can be achieved by new designs of bogie running gear, at little extra first cost and at lower whole life cost.
Transient behaviour of a thermoelectric device
Authors: Naji M , Alata M , Al-Nimr M. A.
Published: April 2011

The objective of this work is to describe the dynamic thermal behaviour of thermoelectric generators and refrigerators. In practical situations, these devices work under transient operating conditions due to the time change in the imposed current, voltage, and hot or cold temperatures. Results for transient temperature distribution were obtained for different parameters. The coefficient of performance was obtained as a function of time for increasing current flow.
The significance of family culture for sports participation
Authors: Wheeler Sharon
Published: April 2011

Contrary to commonplace assumptions regarding ‘determinants’ of sports participation, Birchwood et al. (2008) found strong evidence that family cultures were the chief factor underpinning individuals’ propensities to play sport. The central objective of this study was to investigate family sporting cultures in more detail. To do this, semi-structured interviews were conducted with eight ‘sporty’ children who attend a primary school in North Wales and their parents. The results revealed that there were sporting cultures transmitted through the families studied. These cultures were perhaps best described as ‘habituses’ – sets of beliefs and behaviours in relation to sport with historical and social dimensions. Indeed, it was clear that the parents held specific goals in relation to their children’s sports participation, and employed a set of strategies and practices in order to achieve such goals. These goals, strategies and practices were shaped by the parents’ developmental histories as well as their current relations with other parents.
Participating in Research
Authors: Willis Karen F. , Robinson Andrew , Wood-Baker Richard , Turner Paul , Walters E. Haydn
Published: April 2011

With growing emphasis on the importance of scientific evidence through clinical trials, qualitative studies have been used to deepen our understanding of research from participants’ perspectives. For people with a chronic illness, research participation could represent an additional impost on lives already overwhelmed with medical and care issues, and little is known about participants’ motivations when the research requires them to think differently about their illness and participate over an extended period. We interviewed participants with chronic obstructive pulmonary disease participating in a trial of a chronic disease self-management (CDSM) program. Our finding that people participate in research for altruistic reasons has similarities with other studies. We then extend our understanding of why people participate to explore how they participate. We argue that motivation based on dominant voluntaristic or altruistic values can be problematic for researchers attempting to demonstrate the benefits of CDSM strategies.
Using an unsheared pair to construct the strain ellipse
Authors: Boulanger Ph. , Hayes M.
Published: April 2011

In a finite deformation x = x(X), a particle initially at X is displaced to x. Fundamental to the description of strain are the two Cauchy—Green strain tensors B = FFT and C = F TF, where F = ∂x /∂X is the deformation gradient. Both are real, symmetric and positive definite, so that an ellipsoid at X may be associated with C and an ellipsoid at x with B−1.

The purpose of this note is to consider the strain of infinitesimal material line elements in a typical plane Π at X and dually in a plane π at x. It is shown that if an unsheared pair of material line elements in Π at X is known together with the stretches along the arms of the unsheared pair, then all the features of the strain ellipse at X — that is the elliptical section of the C-ellipsoid by the plane Π — may be determined. Dually, all the features of the strain ellipse at x — that is the section of the B−1-ellipsoid by the plane π — may be determined.

The features of the strain ellipses are determined analytically and also geometrically through use of a ruler and compass.
Facilitative leadership: drawing on Jürgen Habermas’ model of ideal speech to propose a less impositional way to lead
Authors: Fryer Mick
Published: April 2011

Even leadership prescriptions that claim facilitative, democratic or participative credentials struggle to break away from the depiction of leadership as a fundamentally impositional undertaking; a feature which may put many academics and practitioners off the subject altogether. This article therefore calls for more attention to the question of how people who find themselves in leadership roles might lead in a less impositional manner. It also offers a contribution to that agenda. After highlighting some limitations of potential sources of reassurance against leadership’s impositional connotations, the article draws on Jürgen Habermas’ discussion of ideal speech, along with some commentaries on Habermas’ work, to propose an outline for a model of leadership as the facilitation of ideal speech. It also considers the practical feasibility, in contemporary organizations, of leadership that facilitates ideal speech, identifying some aspects of organizational theory and practice that may offer nourishment to such an approach.
The limited scope of policy appraisal in the context of referendum democracy - the case of regulatory impact assessment in Switzerland
Authors: Sager Fritz , Rissi Christof
Published: April 2011

The article investigates how the specific political system context shapes the effectiveness of policy appraisals. Based on a single case study on Regulatory Impact Assessment (RIA) in Switzerland, we argue that the meager impact and success of the RIA is due to its institutional context, namely Swiss semi-direct referendum democracy. Direct democratic involvement and the division of power in the course of consensual government are both great barriers for effective policy appraisal. We conclude by discussing the possibilities and limits of policy appraisal in a polity emphasizing political acceptance over evidence-based policy-making like Switzerland and address the normative issue of legitimacy of public action. Furthermore, we discuss how future research may build upon the presented findings in a more comparative manner.
Discourses of ‘border-crossers’: Peruvian domestic workers in Lima as social actors
Authors: Mick Carola
Published: April 2011

This article is based on narrative, autobiographic interviews with domestic workers in Peru focusing on their migration and work experiences. The interviewees evoke a border discourse that divides and hierarchizes Peruvian society and stigmatizes migrants, especially migrant domestic workers. As domestic service leads to intense social interactions at this ‘border’, the interviewees are constantly forced to ‘translate’ (Bhabha, 1996) when constructing their identity. The discourse-analytical bottom—up perspective focusing on membership categorization devices evaluates the performativity of the discourses of those considered as ‘oppressed’; it analyses processes of subjection and subjectification: whereas some of the interviewees internalize the discursively attributed inferior ‘Me’, others use the constructed borders as an opportunity to develop hybrid discourse strategies that cross and even deconstruct social categorizations. By focusing on the agency of ‘border-crossers’, the article aims at scientifically ‘rethinking the social with cultural difference as a constitutive feature’ (Papastergiadis, 2000: 18).
Multidimensional simulation of diesel engine cold start with advanced physical submodels
Authors: Lippert A. M. , Stanton D. W. , Rutland C. J. , Hallett W. L. H. , Reitz R. D.
Published: April 2011

The complex physical processes occurring during cold starting of diesel engines mandate the use of advanced physical submodels in computations. The present study utilizes a continuous probability density function to represent more fully the range of compositions of commercial fuels. The model was applied to singledroplet calculations to validate the predictions against experimental results. Analysis of a high-pressure diesel spray showed axial composition gradients within the spray. Previous wall-film modelling was extended to include the continuous multicomponent fuel representation. Using these models, the cold-start behaviour of a heavy-duty diesel engine was analysed. The predictions show that multicomponent fuel modelling is critical to capturing realistic vaporization trends. In addition, the spray-film interaction modelling is crucial to capturing the spray impingement and subsequent secondary atomization. Heating the intake air temperature was shown to result in reduced ignition delay and accelerated vaporization. Increasing the fuel temperature increased vaporization prior to and away from the initial heat release. Increasing the injection pressure increased vaporization without much change in the ignition delay. Split injections, with 75 per cent of the fuel contained in the second pulse, displayed a substantial reduction in ignition delay due to ignition of the first pulse. The timing of the first injection was found to be an important parameter due to differences in the spray impingement behaviour with different timings.
Smokeless and low NOx combustion in a dual-fuel diesel engine with induced natural gas as the main fuel
Authors: Ogawa H , Miyamoto N , Li C , Nakazawa S , Akao K
Published: April 2011

In a compression ignition engine, using a rich and lean biform mixture composition that avoids both slightly lean and extremely over-rich regions would be effective in suppressing NOx formation without increasing smoke when the overall air-fuel ratio approaches the stoichiometric ratio. To realize the formation of rich and lean mixtures and the control of ignition timing, a dual-fuel diesel engine with an induced gas with resistance to self-ignition as the main fuel and with a small quantity of diesel fuel for the ignition source has potential merits. However, this method has the problem of knocking and misfiring when the percentage of inducted fuel is increased. In this research smokeless and very low NOx combustion without knocking over a wide operating range was established in a single-cylinder dual-fuel diesel engine with induced natural gas as the main fuel. Optimizations of the combustion chamber shape and operating factors, including exhaust gas recirculation (EGR) and intake air throttling, which determine conditions of the in-cylinder gas, were investigated at several i.m.e.p. (indicated mean effective pressure) conditions. The results of the experiments showed that a combination of the divided cavity, EGR and intake air throttling was effective in simultaneously eliminating knocking and reducing total hydrocarbon (THC) and NOx over a wide i.m.e.p. range. At high i.m.e.p. silent and smooth combustion without knocking was achieved, even with a large amount of induced natural gas. Moreover, the maximum i.m.e.p. increased in comparison with conventional diesel operation with a lower injection pressure system because smoke emission was not a limitation. At medium i.m.e.p. it was effective to adopt EGR and intake air throttling for very low NOx under relatively lower THC. However, at low i.m.e.p. it was difficult to avoid increases in THC and i.s.e.c. (indicated specific energy consumption) while realizing very low NOx and smokeless operation. At lower overall excess air ratio conditions, NOx reduction was shown with a biform mixture composition without slightly lean or extremely rich regions.
Learning theory and technology in university foreign language education The case of French universities
Authors: Whyte Shona
Published: April 2011

Second language study in French universities includes both modern language (literary) and foreign language (communicative) approaches, although teaching is dominated by the literary strand. Traditional educational models based on the transmission of knowledge are unable to accommodate recent progress in our understanding of learning theory, which offers cognitivist and constructivist approaches to learning and teaching. Similar advances specific to second language learning and teaching cannot be reconciled with the standard grammar-translation method, but instead call for communicative, task-oriented classrooms. This article traces the development of learning theory and second language teaching with respect to the roles of teacher and learner, conceptions of language as process or product, and individual versus group learning. It recommends an activity-oriented, project-based approach to second language teaching, learning and evaluation as an appropriate foundation for foreign (non-literary) language learners, including future school teachers, and calls for greater academic recognition of second language research.
Reflecting on reflection
Authors: Absalom Matthew , De Saint Léger Diane
Published: April 2011

The use of reflective tasks, such as journals, as a means to enhance learning is not uncommon in higher education. However, the formative value of reflective tasks is not easily reconciled in tertiary settings where assessment requirements traditionally favour product over process. While learner perception and resolution of this tension have rarely been investigated, research confirms that learners’ level of engagement with the task is a salient parameter for learning to take place (Platt and Brooks, 2002). In other words, if the task is to serve its formative purpose, learners’ perception of and engagement with the task are paramount. The present case study compares learner perceptions of two types of reflective tasks: an online blog and a traditional pen-and-paper learning journal. Findings suggest that reflective tasks can facilitate regular working habits and offer a space for use of the language, and that regular teacher monitoring strongly affects learners’ perceptions of the usefulness of the task.
Using GPS-Enabled Mobile Computing to Augment Qualitative Interviewing: Two Case Studies
Authors: Jones Phil , Drury Rhiannon , McBeath James
Published: April 2011

With the rise of smart phones and ever more sophisticated handheld computers, many that now incorporate GPS (‘‘sat nav’’) technologies, there is tremendous potential for undertaking mixed-method research, including the collection of spatially referenced data. The increasing ubiquity and simplicity of mobile computing, as well as reduced cost, mean that the barriers to social scientists using these devices in the field have been significantly reduced. This article reports on two case studies using these technologies to investigate fear of crime and studentification. Participants generate spatial data simply by walking around an area, interacting with mobile devices through a simplistic interface. The resulting maps allow a more general spatial analysis of the issues to be undertaken, which can then be examined in more depth using qualitative data produced alongside the mobile computing activities. The article concludes that these approaches can be valuable in augmenting conventional qualitative data collection but emphasizes the importance of simple user interfaces both for participants and researcher.
Spontaneous Superior Mesenteric Artery Dissection: Report of 2 Patients and Review of Management Recommendations
Authors: Carter Robert , O'Keeffe Shane , Minion David J. , Sorial Ehab E. , Endean Eric D. , Sarantis Xenos Eleftherios
Published: April 2011

Spontaneous superior mesenteric artery dissection is rare and presents with variable symptomatology. Optimal treatment depends on the presentation; asymptomatic patients can be managed expectantly. Endoluminal intervention or open reconstruction is warranted in patients with persistent symptoms or intestinal ischemia. As more of these patients are identified with increasing utilization of computed tomography (CT), our understanding of the pathophysiology and best treatment will improve.
The Role of Platelet-Rich Plasma in Inguinal Wound Healing in Vascular Surgery Patients
Authors: Lawlor D. Kirk , DeRose Guy , Harris Kenneth A. , Lovell Marge B. , Novick Teresa V. , Forbes Thomas L.
Published: April 2011

The objective was to determine whether incision application of platelet-rich plasma (PRP) will decrease postoperative wound complications in vascular surgery patients. A prospective, randomized trial randomized 81 incisions in 51 patients who underwent femoral artery exposure for elective revascularization procedures or endovascular abdominal aneurysm repairs. Incidence of diabetes, chronic renal failure, prosthetic grafts, body mass index (BMI), and steroid use did not differ. Using the ASEPSIS wound classification system, we found no difference in incidence of wound infection. Wound complications occurred in 9 (23%) of 40 of PRP group and 9 (22%) of 41 of non-PRP. Severe wound complications developed in 5 (13%) PRP and 6 (5%) of non-PRP (P = NS). In multivariate analysis, there were no predictors for wound infection. Groin wound complications rates are common in this patient group. Platelet-rich plasma did not decrease the incidence of groin wound complications in our patients
Percutaneous Management of Segmental Pulmonary Artery Aneurysm in a Patient Without Pulmonary Artery Hypertension
Authors: Rastogi Neeraj , Kabutey Nii- Kabu , Kim Ducksoo , Norbash Alexander
Published: April 2011

Purpose: The aim of this article is to report the percutaneous management of a case of idiopathic segmental pulmonary artery aneurysm (SPAA) in a patient without pulmonary arterial hypertension. Materials and Methods: A 69-year-old female was referred for the evaluation of an incidental finding of a solitary right pulmonary nodule on chest radiograph (CR). Chest computed tomography and pulmonary arteriogram findings were consistent with a solitary SPAA. Successful percutaneous endovascular coil occlusion of the SPAA was performed. Discussion: Segmental pulmonary artery aneurysm considered on CR should be confirmed on initial contrast chest computed tomography. Conclusions: Endovascular coil occlusion is a minimally invasive therapeutic option for idiopathic SPAA.
Potentials of health impact assessment as a local health policy supporting tool
Authors: de Blasio Antonio , Girán János , Nagy Zsuzsanna
Published: April 2011

Planning for health and creating healthy public policy has been one of the main priorities of the Healthy Cities Project since the early 1990s. The Healthy City Foundation of Pécs (Hungary) – as one of the founding cities of the Healthy Cities Project in Europe – has been involved in all phases of health profiling, health planning and health development planning throughout the years. The experiences of the Healthy Cities Project have strengthened the recognition that the decisions of elected local decision-making bodies are generally based on daily demands and not on long-term plans or concepts. The decision-making process has only one type of filtering system (operated by the city notary), which is for the preliminary legal control of the decisions to be made. Quality of life, health and equity are not considered in the system as a filtering issue. This article reports the experiences of the unique approach of health-orientated planning and decision making in the City of Pécs by using the method of health impact assessment (HIA) as a ‘health filter’. It describes the initiative, the success of training and the feasibility of creating a health filter to support the local decision-making process.
The Within-Person Dynamics of Intrinsic and Extrinsic Motivation, Affective States, and Cultural Identification
Authors: Perunovic Wei Qi Elaine , Heller Daniel , Ross Michael , Komar Shawn
Published: April 2011

This study investigates the link between motivational and affective experiences in the daily life of bicultural individuals. Employing a diary design, the authors examined the role of cultural identification in the dynamic goal–affect association in East-Asian Canadian biculturals. Using multilevel modeling procedures, the authors found that momentary cultural identification systematically moderated the association between extrinsic motivation and Negative Affect (NA) over time. Similar to previous findings observed from monocultural Westerners, biculturals in this study showed a positive association between extrinsic motivation and NA when they identified with Western culture. When they identified with Asian culture, however, biculturals' extrinsic motivation was not linked to NA, suggesting that when their Asian identity is salient, they are less negatively influenced by extrinsic goal pursuit than when they identified with Western culture. Findings indicate the importance of within-individual short-term variations in cultural identification for understanding the affective implications of extrinsic motivation in the lives of bicultural individuals.
Targeting of microRNA-142-3p in dendritic cells regulates endotoxin-induced mortality
Authors: Sun Yaping , Varambally Sooryanarayana , Maher Christopher A. , Cao Qi , Chockley Peter , Toubai Tomomi , Malter Chelsea , Nieves Evelyn , Tawara Isao , Wang Yongqing , Ward Peter A. , Chinnaiyan Arul , Reddy Pavan
Published: April 2011

While miRNAs are increasingly linked to various immune responses, whether they can be targeted for regulating in vivo inflammatory processes such as endotoxin-induced Gram-negative sepsis is not known. Production of cytokines by the dendritic cells (DCs) plays a critical role in response to endotoxin, lipopolysaccharide (LPS). We profiled the miRNA and mRNA of CD11c+ DCs in an unbiased manner and found that at baseline, miR-142-3p was among the most highly expressed endogenous miRs while IL-6 was among the most highly expressed mRNA after LPS stimulation. Multiple computational algorithms predicted the IL-6 3′ untranslated region (UTR) to be a target of miR-142-3p. Studies using luciferase reporters carrying wild-type (WT) and mutant IL-6 3′UTR confirmed IL-6 as a target for miR-142-3p. In vitro knockdown and overexpression studies demonstrated a critical and specific role for miR142-3p in regulating IL-6 production by the DCs after LPS stimulation. Importantly, treatment of only WT but not the IL-6–deficient (IL-6−/−) mice with locked nucleic acid (LNA)–modified phosphorothioate oligonucleotide complementary to miR 142-3p reduced endotoxin-induced mortality. These results demonstrate a critical role for miR-142-3p in regulating DC responses to LPS and provide proof of concept for targeting miRs as a novel strategy for treatment of endotoxin-induced mortality.
Deglycosylation and label-free quantitative LC-MALDI MS applied to efficient serum biomarker discovery of lung cancer
Authors: Toyama Atsuhiko , Nakagawa Hidewaki , Matsuda Koichi , Ishikawa Nobuhisa , Kohno Nobuoki , Daigo Yataro , Sato Taka-Aki , Nakamura Yusuke , Ueda Koji
Published: April 2011

Background

Serum is an ideal source of biomarker discovery and proteomic profiling studies are continuously pursued on serum samples. However, serum is featured by high level of protein glycosylations that often cause ionization suppression and confound accurate quantification analysis by mass spectrometry. Here we investigated the effect of N-glycan and sialic acid removal from serum proteins on the performance of label-free quantification results.

Results

Serum tryptic digests with or without deglycosylation treatment were analyzed by LC-MALDI MS and quantitatively compared on the Expressionist Refiner MS module. As a result, 345 out of 2,984 peaks (11.6%) showed the specific detection or the significantly improved intensities in deglycosylated serum samples (P< 0.01). We then applied this deglycosylation-based sample preparation to the identification of lung cancer biomarkers. In comparison between 10 healthy controls and 20 lung cancer patients, 40 peptides were identified to be differentially presented (P< 0.01). Their quantitative accuracies were further verified by multiple reaction monitoring. The result showed that deglycosylation was needed for the identification of some unique candidates, including previously unreported O-linked glycopeptide of complement component C9.

Conclusions

We demonstrated here that sample deglycosylation improves the quantitative performance of shotgun proteomics, which can be effectively applied to any samples with high glycoprotein contents.
An assessment of mental health policy in Ghana, South Africa, Uganda and Zambia
Authors: Faydi Edwige , Funk Michelle , Kleintjes Sharon , Ofori-Atta Angela , Ssbunnya Joshua , Mwanza Jason , Kim Caroline , Flisher Alan
Published: April 2011

Background

Approximately half of the countries in the African Region had a mental health policy by 2005, but little is known about quality of mental health policies in Africa and globally. This paper reports the results of an assessment of the mental health policies of Ghana, South Africa, Uganda and Zambia.

Methods

The WHO Mental Health Policy Checklist was used to evaluate the most current mental health policy in each country. Assessments were completed and reviewed by a specially constituted national committee as well as an independent WHO team. Results of each country evaluation were discussed until consensus was reached.

Results

All four policies received a high level mandate. Each policy addressed community-based services, the integration of mental health into general health care, promotion of mental health and rehabilitation. Prevention was addressed in the South African and Ugandan policies only. Use of evidence for policy development varied considerably. Consultations were mainly held with the mental health sector. Only the Zambian policy presented a clear vision, while three of four countries spelt out values and principles, the need to establish a coordinating body for mental health, and to protect the human rights of people with mental health problems. None included all the basic elements of a policy, nor specified sources and levels of funding for implementation. Deinstitutionalisation and the provision of essential psychotropic medicines were insufficiently addressed. Advocacy, empowerment of users and families and intersectoral collaboration were inadequately addressed. Only Uganda sufficiently outlined a mental health information system, research and evaluation, while only Ghana comprehensively addressed human resources and training requirements. No country had an accompanying strategic mental health plan to allow the development and implementation of concrete strategies and activities.

Conclusions

Six gaps which could impact on the policies' effect on countries' mental health systems were: lack of internal consistency of structure and content of policies, superficiality of key international concepts, lack of evidence on which to base policy directions, inadequate political support, poor integration of mental health policies within the overall national policy and legislative framework, and lack of financial specificity. Three strategies to address these concerns emerged, namely strengthening capacity of key stakeholders in public (mental) health and policy development, creation of a culture of inclusive and dynamic policy development, and coordinated action to optimize use of available resources.
Temporal profiles of age-dependent changes in cytokine mRNA expression and glial cell activation after status epilepticus in postnatal rat hippocampus
Authors: Järvelä Juha T , Lopez-Picon Francisco R , Plysjuk Anna , Ruohonen Saku , Holopainen Irma E
Published: April 2011

Background

Status epilepticus (SE) is proposed to lead to an age-dependent acute activation of a repertoire of inflammatory processes, which may contribute to neuronal damage in the hippocampus. The extent and temporal profiles of activation of these processes are well known in the adult brain, but less so in the developing brain. We have now further elucidated to what extent inflammation is activated by SE by investigating the acute expression of several cytokines and subacute glial reactivity in the postnatal rat hippocampus.

Methods

SE was induced by an intraperitoneal (i.p.) injection of kainic acid (KA) in 9- and 21-day-old (P9 and P21) rats. The mRNA expression of interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), matrix metalloproteinase-9 (MMP-9), glial-derived neurotrophic factor (GDNF), interferon gamma (IFN-γ), and transforming growth factor-beta 1 (TGF-β1) were measured from 4 h up to 3 days after KA injection with real-time quantitative PCR (qPCR). IL-1β protein expression was studied with ELISA, GFAP expression with western blotting, and microglial and astrocyte morphology with immunohistochemistry 3 days after SE.

Results

SE increased mRNA expression of IL-1β, TNF-α and IL-10 mRNA in hippocampus of both P9 and P21 rats, their induction being more rapid and pronounced in P21 than in P9 rats. MMP-9 expression was augmented similarly in both age groups and GDNF expression augmented only in P21 rats, whereas neither IFN-γ nor TGF-β1 expression was induced in either age group. Microglia and astrocytes exhibited activated morphology in the hippocampus of P21 rats, but not in P9 rats 3 d after SE. Microglial activation was most pronounced in the CA1 region and also detected in the basomedial amygdala.

Conclusion

Our results suggest that SE provokes an age-specific cytokine expression in the acute phase, and age-specific glial cell activation in the subacute phase as verified now in the postnatal rat hippocampus. In the juvenile hippocampus, transient increases in cytokine mRNA expression after SE, in contrast to prolonged glial reactivity and region-specific microglial activity after SE, suggest that the inflammatory response is changed from a fulminant and general initial phase to a more moderate and specific subacute response.
Hepatitis E virus ORF2 protein over-expressed by baculovirus in hepatoma cells, efficiently encapsidates and transmits the viral RNA to naïve cells
Authors: Parvez Mohammad K , Purcell Robert H , Emerson Suzanne U
Published: April 2011

A recombinant baculovirus(vBacORF2) that expressed the full-length ORF2 capsid protein of a genotype 1 strain of hepatitis E virus(HEV) was constructed. Transduction of S10-3 human hepatoma cells with this baculovirus led to large amounts of ORF2 protein production in ~50% of the cells as determined by immune fluorescence microscopy. The majority of the ORF2 protein detected by Western blot was 72 kDa, the size expected for the full-length protein. To determine if the exogenously-supplied ORF2 protein could transencapsidate viral genomes, S10-3 cell cultures that had been transfected the previous day with an HEV replicon of genotype 1 that contained the gene for green fluorescent protein(GFP), in place of that for ORF2 protein, were transduced with the vBacORF2 virus. Cell lysates were prepared 5 days later and tested for the ability to deliver the GFP gene to HepG2/C3A cells, another human hepatoma cell line. FACS analysis indicated that lysates from cell cultures receiving only the GFP replicon were incapable of introducing the replicon into the HepG2/C3A cells whereas ~2% of the HepG2/C3A cells that received lysate from cultures that had received both the replicon and the baculovirus produced GFP. Therefore, the baculovirus-expressed ORF2 protein was able to trans-encapsidate the viral replicon and form a particle that could infect naïve HepG2/C3A cells. This ex vivo RNA packaging system should be useful for studying many aspects of HEV molecular biology.
Effect of a fat spread enriched with medium-chain triacylglycerols and a special fatty acid-micronutrient combination on cardiometabolic risk factors in overweight patients with diabetes
Authors: Siener Roswitha , Ehrhardt Christina , Bitterlich Norman , Metzner Christine
Published: April 2011

Background

Medium-chain triacylglycerols (MCT), omega-3 polyunsaturated fatty acids (n-3-PUFA) and micronutrients may be useful for weight and cardiometabolic risk management. However, studies analyzing the effect of a combination of both in individuals at increased cardiometabolic risk are lacking. Therefore, this randomized, controlled, double-blind study investigated the effect of a fat spread enriched with two different doses of MCT and a special long-chain fatty acid-micronutrient combination on cardiometabolic risk factors in overweight diabetic patients.

Methods

Fifty-four patients received either a fat spread with 6 g/d MCT (MCT30%) or 1.2 g/d (MCT6%). Forty-three completed the study. Analysis was performed according to the median of MCT intake (supplemented and food-derived MCT). Clinical, anthropometric, blood, 24 h-urine parameters and dietary intake were assessed at baseline and after 12 weeks.

Results

Total MCT intake > 7 g/d (MCT > 7 group) significantly reduced waist circumference (WC) by 1.81 ± 2.69 cm, whereas ≤ 7 g/d MCT (MCT ≤ 7 group) increased WC by 0.32 ± 3.03 cm (p = 0.027), which was supported by a change in waist-to-height ratio (WHtR) (p = 0.018). Fasting serum triglycerides (TG) increased in both groups over time due to dietary habits. In contrast, diabetic metabolic situation and urinary albumin excretion did not alter. Urinary pH differed significantly between groups after 12 weeks.

Conclusion

An intake of >7 g/d MCT reduced WC in overweight diabetics, whereas the increase in the intake of fatty acids may have worsened fasting TG. Therefore, the suitability of a fat for nutrient enrichment remains to be challenged, and further studies in low-fat matrices are desirable.
IL-15 ex vivo overcomes CD4+ T cell deficiency for the induction of human antigen-specific CD8+ T cell responses
Authors: Yu Huifeng , Tawab-Amiri Abdul , Dzutsev Amiran , Sabatino Marianna , Aleman Karen , Yarchoan Robert , Terabe Masaki , Sui Yongjun , Berzofsky Jay A
Published: April 2011

CD4+ Th cells are important for the induction and maintenance of antigen-specific CD8+ T cell function, so their loss or dysfunction in HIV-infected or cancer patients could reduce the patients' ability to control viral infection. Previous work in murine systems indicated that IL-15 codelivered with vaccines could overcome CD4+ Th cell deficiency for induction of functionally efficient CD8+ T cells and maintenance of viral-specific CTLs, but its efficacy in helping primary human CD8+ T cell responses is unknown. In the present study, a peptide-pulsed, DC-based human coculture ex vivo system was used to study the role of IL-15 in overcoming CD4+ Th deficiency to elicit CD8+ T cell responses in CD4-depleted PBMCs from healthy individuals and PBMCs from HIV-1-infected patients. We found that IL-15 could overcome CD4+ Th deficiency to induce primary and recall memory CD8+ T cell responses in healthy individuals. Moreover, in CD4-deficient, HIV-1-infected patients with diminished CD8+ T cell responses, IL-15 greatly enhanced CD8+ T cell responses to alloantigen. These results suggest that IL-15 may be useful in the development of therapeutic and preventive vaccines against cancers and viral infections in patients defective in CD4+ Th cell.