bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of the nitric oxide pathway in AMPK-mediated glucose uptake and GLUT4 translocation in heart muscle
Authors: Li Ji , Hu Xiaoyue , Selvakumar Pradeepa , Russell Raymond R. , Cushman Samuel W. , Holman Geoffrey D. , Young Lawrence H.
Published: July 2004

AMP-activated protein kinase (AMPK) is a serine-threonine kinase that regulates cellular metabolism and has an essential role in activating glucose transport during hypoxia and ischemia. The mechanisms responsible for AMPK stimulation of glucose transport are uncertain, but may involve interaction with other signaling pathways or direct effects on GLUT vesicular trafficking. One potential downstream mediator of AMPK signaling is the nitric oxide pathway. The aim of this study was to examine the extent to which AMPK mediates glucose transport through activation of the nitric oxide (NO)-signaling pathway in isolated heart muscles. Incubation with 1 mM 5-amino-4-imidazole-1-β-carboxamide ribofuranoside (AICAR) activated AMPK ( P < 0.01) and stimulated glucose uptake ( P < 0.05) and translocation of the cardiomyocyte glucose transporter GLUT4 to the cell surface ( P < 0.05). AICAR treatment increased phosphorylation of endothelial NO synthase (eNOS) ∼1.8-fold ( P < 0.05). eNOS, but not neuronal NOS, coimmunoprecipitated with both the α2 and α1 AMPK catalytic subunits in heart muscle. NO donors also increased glucose uptake and GLUT4 translocation ( P < 0.05). Inhibition of NOS with Nω-nitro-l-arginine and Nω-methyl-l-arginine reduced AICAR-stimulated glucose uptake by 21 ± 3% ( P < 0.05) and 25 ± 4% ( P < 0.05), respectively. Inhibition of guanylate cyclase with ODQ and LY-83583 reduced AICAR-stimulated glucose uptake by 31 ± 4% ( P < 0.05) and 22 ± 3% ( P < 0.05), respectively, as well as GLUT4 translocation to the cell surface ( P < 0.05). Taken together, these results indicate that activation of the NO-guanylate cyclase pathway contributes to, but is not the sole mediator of, AMPK stimulation of glucose uptake and GLUT4 translocation in heart muscle.
Angiotensin II induces carbon monoxide production in the perfused kidney: relationship to protein kinase C activation
Authors: Li Ping , Jiang Houli , Yang LiMing , Quan Shuo , Dinocca Sandra , Rodriguez Francisca , Abraham Nader G. , Nasjletti Alberto
Published: July 2004

Heme oxygenase (HO)-derived carbon monoxide (CO) attenuates vascular reactivity to constrictor stimuli. ANG II produces vasoconstriction and induces HO-1 isoform expression. However, direct evidence that ANG II promotes HO product generation is lacking. Therefore, we examined the effects of ANG II on CO release and HO isoform expression in isolated rat kidneys. Kidneys were perfused with oxygenated Krebs buffer. ANG II (1 μmol/l) increased ( P < 0.05) perfusion pressure from 97 ± 9 to 150 ± 14 mmHg; it also increased ( P < 0.05) the concentration of CO in the venous effluent (from 27.1 ± 11.9 to 45.6 ± 11.7, 62.5 ± 16.7, 94.8 ± 20.7, and 101.9 ± 13.1 nmol/l after 30, 60, 90, and 120 min, respectively). The pressor effect of ANG II was blunted ( P < 0.05) in kidneys perfused with buffer containing losartan (10 μmol/l) or PKC inhibitors staurosporine (0.1 μmol/l) or calphostin C (1 μmol/l). Kidneys perfused with buffer containing ANG II for 120 min also displayed increased ( P < 0.05) HO-1 expression. Stannous mesoporphyrin (30 μmol/l) decreased CO release ( P < 0.05) in preparations perfused with and without ANG II; the HO inhibitor also increased ( P < 0.05) perfusion pressure, more so in kidneys perfused with that without ANG II. We conclude that ANG II stimulates CO production and release in isolated, perfused rat kidneys. This action of ANG II is linked to the activation of AT1receptors and involves PKC activation and upregulation of renal HO-1 but not of HO-2 protein expression. The study suggests upregulation of renal HO-1 and CO release are protagonic events in a counterregulatory mechanism that attenuates ANG II-induced renal vasoconstriction.
Alterations in P2X and P2Y purinergic receptor expression in urinary bladder from normal cats and cats with interstitial cystitis
Authors: Birder L. A. , Ruan H. Z. , Chopra B. , Xiang Z. , Barrick S. , Buffington C. A. , Roppolo J. R. , Ford A. P. D. W. , de Groat W. C. , Burnstock G.
Published: July 2004

Purinergic mechanisms appear to be involved in motor as well as sensory functions in the urinary bladder. ATP released from efferent nerves excites bladder smooth muscle, whereas ATP released from urothelial cells can activate afferent nerves and urothelial cells. In the present study, we used immunohistochemical techniques to examine the distribution of purinoceptors in the urothelium, smooth muscle, and nerves of the normal cat urinary bladder as well as possible changes in the expression of these receptors in cats with a chronic painful bladder condition termed feline interstitial cystitis (FIC) in which ATP release from the urothelium is increased. In normal cats, a range of P2X (P2X1, P2X2, P2X3, P2X4, P2X5, P2X6, and P2X7) and P2Y (P2Y1, P2Y2, and P2Y4) receptor subtypes was expressed throughout the bladder urothelium. In FIC cats, there is a marked reduction in P2X1and loss of P2Y2receptor staining. Both P2X3and P2Y4are present in nerves in normal cat bladder, and no obvious differences in staining were detected in FIC. Smooth muscle in the normal bladder did not exhibit P2Y receptor staining but did exhibit P2X (P2X2, P2X1) staining. In the FIC bladder smooth muscle, there was a significant reduction in P2X1expression. These findings raise the possibility that purinergic mechanisms in the urothelium and bladder smooth muscle are altered in FIC cats. Because the urothelial cells appear to have a sensory function in the bladder, it is possible that the plasticity in urothelial purinergic receptors is linked with the painful bladder symptoms in IC.
Giα3 protein-coupled dopamine D3receptor-mediated inhibition of renal NHE3 activity in SHR proximal tubular cells is a PLC-PKC-mediated event
Authors: Pedrosa Rui , Gomes Pedro , Hopfer Ulrich , Jose Pedro A. , Soares-da-Silva Patrício
Published: July 2004

This study evaluated the transduction pathway associated with type 3 Na+/H+exchanger (NHE3) activity-induced inhibition during dopamine D3receptor activation in immortalized renal proximal tubular epithelial cells from the spontaneously hypertensive rat. The dopamine D3receptor agonist 7-OH-DPAT decreased NHE3 activity, which was prevented by the D2-like receptor antagonist S-sulpiride, pertussis toxin (PTX; overnight treatment), and the PKC inhibitor chelerythrine, but not by cholera toxin (overnight treatment), the MAPK inhibitor PD-098059, or the p38 inhibitor SB-203580. The PKA inhibitor H-89 abolished the inhibitory effects of forskolin on NHE3 activity, but not that of 7-OH-DPAT. The phospholipase C (PLC) inhibitor U-73122 prevented the inhibitory effects of 7-OH-DPAT, whereas PDBu and 7-OH-DPAT increased PLC activity and reduced NHE3 activity; downregulation of PKC abolished the inhibitory effects of both PDBu and 7-OH-DPAT on NHE activity. The inhibition of NHE3 activity by GTPγS and the prevention of the effect of 7-OH-DPAT by PTX suggest an involvement of a Gi/oprotein coupled to the dopamine D3receptor. Indeed, the 7-OH-DPAT-induced decrease in NHE3 activity was abolished in cells treated overnight with the anti-Giα3 antibody, but not in cells treated with antibodies against Gq/11, Gsα, Gβ, and Giα1,2 proteins. The calcium ionophore A-23187 and the Ca2+-ATPase inhibitor thapsigargin increased intracellular Ca2+but did not affect NHE3 activity. However, the inhibitory effects of PDBu and 7-OH-DPAT on NHE3 activity were completely abolished by A-23287 and thapsigargin. It is concluded that inhibition of NHE3 activity by dopamine D3receptors coupled to Giα3 proteins is a PLC-PKC-mediated event, modulated by intracellular Ca2+.
Relative contribution of OAT and OCT transporters to organic electrolyte transport in rabbit proximal tubule
Authors: Zhang Xiaohong , Groves Carlotta E. , Bahn Andrew , Barendt Wendy M. , Prado Marcos D. , Rödiger Matthias , Chatsudthipong Varanuj , Burckhardt Gerhard , Wright Stephen H.
Published: July 2004

We compared the characteristics of several cloned rabbit organic electrolyte (OE) transporters expressed in cultured cells with their behavior in intact rabbit renal proximal tubules (RPT) to determine the contribution of each to basolateral uptake of the weak acid ochratoxin A (OTA) and the weak base cimetidine (CIM). The activity of organic anion transporters OAT1 and OAT3 proved to be distinguishable because OAT1 had a high affinity for PAH ( Ktof 20 μM) and did not support estrone sulfate (ES) transport, whereas OAT3 had a high affinity for ES ( Ktof 4.5 μM) and a weak interaction with PAH (IC50> 1 mM). In contrast, both transporters robustly accumulated OTA. Intact RPT also accumulated OTA, with OAT1 and OAT3 each responsible for ∼50%: ES and PAH each reduced uptake by ∼50%, and the combination of the two eliminated mediated OTA uptake. The weak base CIM was transported by OAT3 ( Ktof 80 μM) and OCT2 ( Ktof 2 μM); OCT1 had a comparatively low affinity for CIM, and CIM uptake by OAT1 was equivocal. Intact RPT accumulated CIM, with TEA and ES reducing CIM uptake by 20 and 75%, respectively, suggesting that OAT3 plays a quantitatively more significant role in CIM uptake in the early proximal tubule than OCT1/2. In single S2 segments of RPT, ES and TEA each blocked ∼50% of CIM uptake. Thus the fractional contribution of different OE transporters to renal secretion is influenced by their affinity for substrate and relative expression level in RPT.
Differential traffic of proximal tubule Na+transporters during hypertension or PTH: NHE3 to base of microvilli vs. NaPi2 to endosomes
Authors: Yang Li E. , Maunsbach Arvid B. , Leong Patrick K. K. , McDonough Alicia A.
Published: July 2004

We previously reported that Na+/H+exchanger type 3 (NHE3) and NaPi2 are acutely retracted from the proximal tubule (PT) microvilli (MV) during acute hypertension [high blood pressure (BP)] or parathyroid hormone (PTH) treatment. By subcellular membrane fractionation, NHE3 and NaPi2 show indistinguishable redistribution patterns out of light-density into heavy-density membranes in response to either treatment consistent with a retraction from the apical MV to the intermicrovillar cleft region. This study aimed to examine the redistribution of PT NHE3 vs. NaPi2 by confocal and electron microscopy during high BP and during PTH treatment to determine whether their respective destinations overlap or are distinct. High-BP protocol: systolic BP was increased 50–60 mmHg by increasing peripheral resistance for 20 min; PTH protocol: rats were infused with 6.6 μg/kg iv of PTH followed by 0.1 μg·kg−1·min−1infusion for 1 h. For light microscopy, rats were infused with 25 mg of horseradish peroxidase (HRP) 10 min before kidney fixation. Kidney slices were dual labeled with either NHE3 or NaPi2 and either clathrin-coated vesicle adaptor protein AP2 or endosome marker HRP. The results demonstrate retraction of NHE3 from the MV to the base of MV during either high-BP or PTH treatment: NHE3 staining did not retract below the AP2-stained domain or to HRP-labeled endosomes in either model. In comparison, NaPi2 was retracted from MV to below the AP2-stained region in both models, a little colocalizing with HRP staining. At the electron microscopic level with immunogold labeling, during high BP NHE3 was concentrated in a distinct domain in the base of the MV while NaPi2 moved to endosomes. The results demonstrate that there are divergent routes of retraction of PT NHE3 and NaPi2 from the MV during acute hypertension or PTH treatment: NHE3 is not internalized but remains at the base of the MV while NaPi2 is internalized.
Enhanced Excitability Compensates for High-Pressure-Induced Depression of Cortical Inputs to the Hippocampus
Authors: Talpalar Adolfo E. , Grossman Yoram
Published: July 2004

High pressure (>1.0 MPa) induces the high-pressure neurological syndrome (HPNS) characterized by increased excitability of the CNS and cognitive impairments involving memory disorders. The perforant-path transfer of cortical information to the hippocampal formation is important for memory acquisition. High pressure may alter information transfer in this connection. We used rat corticohippocampal slices for studying the effect of pressure on the transfer function between synaptic inputs from the medial perforant path (MPP) and spike generation by granule cells (GC) of the dentate gyrus. High pressure (10.1 MPa) reduced single MPP field excitatory postsynaptic potential (fEPSP) amplitude and slope by nearly 50%. Field antidromic action potentials (AAPs) elicited by stimulation of GC axons, and population spike (PS) generation by the pressure-depressed MPP fEPSP were not significantly altered at hyperbaric conditions. Nevertheless the relationship PS/fEPSP increased at high pressure, indicating dendritic hyperexcitability in the GC. PSs elicited by paired-pulse MPP fEPSPs at 10- to 200-ms interstimulus intervals and PS generated by trains of five fEPSPs at 25 Hz were also not affected in spite of severe pressure-induced synaptic depression. Similarly, trains of AAPs at 25–50 Hz were not significantly changed. Trains of fEPSPs at higher frequency (50 Hz), however, induced additional spikes at high pressure, indicating pressure disruption of the regular low-pass filter properties of the DG. Such effect was closely mimicked by partial blockade of GABAA inhibition. High pressure depresses synaptic activity while increases excitability in the neuronal dendrites but not in the axons. This mechanism, allowing neuronal communication at low input signals, may partially cope with pressure effects at the low frequency range (<25 Hz) but losses reliability at higher frequencies (>50 Hz).
Serotonergic and Nonserotonergic Dorsal Raphe Neurons Are Pharmacologically and Electrophysiologically Heterogeneous
Authors: Marinelli Silvia , Schnell Stephen A. , Hack Stephen P. , Christie MacDonald J. , Wessendorf Martin W. , Vaughan Christopher W.
Published: July 2004

The dorsal raphe nucleus (DRN) projects serotonergic axons throughout the brain and is involved in a variety of physiological functions. However, it also includes a large population of cells that contain other neurotransmitters. To clarify the physiological and pharmacological differences between the serotonergic and nonserotonergic neurons of the DRN, their postsynaptic responses to 5-hydroxytryptamine (5-HT, serotonin) and to selective activation of 5-HT1A or 5-HT2A/C receptors and their action potential characteristics were determined using in vitro patch-clamp recordings. The slices containing these neurons were then immunostained for tryptophan hydroxylase (TPH), a marker of serotonergic neurons. It was found that subpopulations of both serotonergic and nonserotonergic neurons responded to 5-HT with outward (i.e., inhibitory) and inward (i.e., excitatory) currents, responded to both 5-HT1A and 5-HT2A/C receptor activation with outward and inward currents, respectively, and displayed overlapping action potential characteristics. These findings suggest that serotonergic and nonserotonergic neurons in the DRN are both heterogeneous with respect to their individual pharmacological and electrophysiological characteristics. The findings also suggest that the activity of the different populations of DRN neurons will display heterogeneous changes when the serotonergic tone in the DRN is altered by neurological disorders or by drug treatment.
Molecular Structure and Physiological Functions of GABABReceptors
Authors: Bettler Bernhard , Kaupmann Klemens , Mosbacher Johannes , Gassmann Martin
Published: July 2004

GABABreceptors are broadly expressed in the nervous system and have been implicated in a wide variety of neurological and psychiatric disorders. The cloning of the first GABABreceptor cDNAs in 1997 revived interest in these receptors and their potential as therapeutic targets. With the availability of molecular tools, rapid progress was made in our understanding of the GABABsystem. This led to the surprising discovery that GABABreceptors need to assemble from distinct subunits to function and provided exciting new insights into the structure of G protein-coupled receptors (GPCRs) in general. As a consequence of this discovery, it is now widely accepted that GPCRs can exist as heterodimers. The cloning of GABABreceptors allowed some important questions in the field to be answered. It is now clear that molecular studies do not support the existence of pharmacologically distinct GABABreceptors, as predicted by work on native receptors. Advances were also made in clarifying the relationship between GABABreceptors and the receptors for γ-hydroxybutyrate, an emerging drug of abuse. There are now the first indications linking GABABreceptor polymorphisms to epilepsy. Significantly, the cloning of GABABreceptors enabled identification of the first allosteric GABABreceptor compounds, which is expected to broaden the spectrum of therapeutic applications. Here we review current concepts on the molecular composition and function of GABABreceptors and discuss ongoing drug-discovery efforts.
Urinary Bladder Contraction and Relaxation: Physiology and Pathophysiology
Authors: Andersson Karl-Erik , Arner Anders
Published: July 2004

The detrusor smooth muscle is the main muscle component of the urinary bladder wall. Its ability to contract over a large length interval and to relax determines the bladder function during filling and micturition. These processes are regulated by several external nervous and hormonal control systems, and the detrusor contains multiple receptors and signaling pathways. Functional changes of the detrusor can be found in several clinically important conditions, e.g., lower urinary tract symptoms (LUTS) and bladder outlet obstruction. The aim of this review is to summarize and synthesize basic information and recent advances in the understanding of the properties of the detrusor smooth muscle, its contractile system, cellular signaling, membrane properties, and cellular receptors. Alterations in these systems in pathological conditions of the bladder wall are described, and some areas for future research are suggested.
Molecular and Cellular Physiology of Renal Organic Cation and Anion Transport
Authors: Wright Stephen H. , Dantzler William H.
Published: July 2004

Organic cations and anions (OCs and OAs, respectively) constitute an extraordinarily diverse array of compounds of physiological, pharmacological, and toxicological importance. Renal secretion of these compounds, which occurs principally along the proximal portion of the nephron, plays a critical role in regulating their plasma concentrations and in clearing the body of potentially toxic xenobiotics agents. The transepithelial transport involves separate entry and exit steps at the basolateral and luminal aspects of renal tubular cells. It is increasingly apparent that basolateral and luminal OC and OA transport reflects the concerted activity of a suite of separate transport processes arranged in parallel in each pole of proximal tubule cells. The cloning of multiple members of several distinct transport families, the subsequent characterization of their activity, and their subcellular localization within distinct regions of the kidney now allows the development of models describing the molecular basis of the renal secretion of OCs and OAs. This review examines recent work on this issue, with particular emphasis on attempts to integrate information concerning the activity of cloned transporters in heterologous expression systems to that observed in studies of physiologically intact renal systems.
Expatriation as a Maturation Opportunity: A Psychoanalytical Approach Based on ‘Copy and Paste’
Authors: Cerdin Jean-Luc , Dubouloy Maryse
Published: July 2004

In order to understand the success of an expatriation, the traditional approach generally focuses on theoretical models of the expatriate’s adjustment. The psychoanalytical approach seems more powerful in that it sheds light on the significant changes in the individual’s perception of himself and of his environment brought about by the experience of expatriation. In the psychoanalytical approach developed in this article, expatriation may be seen as a maturation opportunity for the individual. The concept of transitional space helps us to understand how people move from ‘copy and cut’ to ‘copy and paste’. Moving from copy to paste is a necessary stage to achieve autonomy. Using the psychoanalytical approach throws light on and reinforces the discoveries presented in the traditional approach literature. An empirical study allows us to confront our theoretical approach to individuals’ factual experiences of expatriation. Implications for both organizations and individuals are presented, in particular, the scope of their responsibilities regarding the expatriation decision.
Poles and Germans: An International Business Relationship
Authors: Mattos Anna Gajewsksa-De , Chapman Malcolm , Clegg Jeremy
Published: July 2004

In this article, we aim to identify and explain how Polish managers, in the Polish affiliates of German companies, view their German partners. The theoretical background for this article comes from the field of social anthropology. The empirical data were collected during face-to-face, semi-structured interviews with executives in Poland. The findings presented here are the result of qualitative analysis. We argue that the Polish/German contrast, as perceived by Polish managers, bears a strong resemblance to other core/periphery ethnic relationships in Europe. Parallels are drawn from the British Isles. We argue that the characterizations discussed play an important role in allowing managers to understand their business roles and capabilities within an international business context. A major shortcoming in international business research is the poor understanding of these ingrained attitudes. Our study aims to fill this gap.
Evaluating Appreciative Inquiry: A Relational Constructionist Perspective
Authors: van der Haar Dorieke , Hosking Dian Marie
Published: July 2004

Appreciative inquiry (AI) has become increasingly popular as a social constructionist approach to organizational change and development. Many claims are made about its status and value but there are few published evaluation studies. Furthermore, some interesting and important issues arise as to how AI can be evaluated appropriately – given its social constructionist context. The heart of our argument is that AI could appropriately and usefully be evaluated using the approach of ‘responsive evaluation’. We lay out our views by putting forward a particular, relational, narrative of social construction processes. We then draw upon this relational narrative to develop three themes. One theme is that both AI and social constructionism should be viewed as variable social constructions and not fixed ‘things’. This means that AI manifests in many different ways in different local-cultural and local-historical contexts. 1 A related theme is that, if theory and method co-define one another, then AI is much more than just a method. Finally, viewing evaluation as a variable social construction suggests that some evaluation practices will be more consistent with the premises of relational constructionism and AI than others. These themes are developed in several parts. In the first, we briefly introduce AI, the links that have been made between it and social constructionism, and potential implications of these links for evaluation. In the second, we outline the defining premises of relational constructionism. In the third, we examine AI, its multiple meanings, and its central premises. We then explore links between relational constructionism and AI. This brings us to the fifth part in which we introduce evaluation and its potential relations with AI. Finally, we write of how AI and evaluation could be performed in ways that reflect relational constructionist premises.
Characteristics and Personal Social Networks of the on-the-Street, of-the-Street, Shelter and School Children in Eldoret, Kenya
Authors: Ayuku David O. , Kaplan Charles , Baars Herman , de Vries Marten
Published: July 2004

Most of the street-based children are not educated beyond primary school and their living conditions are based on begging and doing odd jobs in the market and streets. Forty-six percent of the on-the-street children live with one parent, and 97 percent of the of-the-street children have lost contact with their parents. The on-the-street children have a higher percentage of family sector networks than the of-the-street children and the shelter or institutionalized children. Generally, school children still have strong family ties.
The Social Work Practitioner-Researcher-Educator
Authors: Chan Cecilia L.W. , Ng S. M.
Published: July 2004

Teaching, practice and research are the three integral missions of social work educators. This article uses examples of the empowerment curriculum and problem-based learning to illustrate how social work teachers can play the role of a practitioner-researcher-educator to promote social justice and anti-discrimination in the globalization process.
The Search from within
Authors: Kee Ling How
Published: July 2004

This article highlights the inextricable relationship between research methodology, ways of knowing and culture. Issues and problems of applying western research methodology in the context of the writer’s research in Malaysia are discussed. The writer concludes that theoretical development of culturally appropriate social work practice needs to be conducted within an indigenous research paradigm.
Defining the Role of the Hospital Social Worker in Australia
Authors: Davis Cindy , Baldry Eileen , Milosevic Biljana , Walsh Anne
Published: July 2004

This study assessed the role of the hospital social worker during the hospital stay and post-discharge period. Findings revealed that social workers performed various tasks, and the most common concerns of patients were coping and/or post-discharge issues. Findings also demonstrated the complexity of this role in meeting the needs of patients.
Defining Social Work for the 21st Century
Authors: Hare Isadora
Published: July 2004

The IFSW recently adopted a new joint international de.nition of social work, together with the IASSW. The de.nition embraces both traditional social work activities and social development, and addresses social work knowledge, values and practice in an age of globalization. This article analyzes the concepts selected and explains their meaning and signi.cance for the profession.
Application of the Finite-Element Method to Predict the Onset of Delamination Growth
Authors: Jimenez Miguel A. , Miravete Antonio
Published: July 2004

This paper deals with a basic methodology for the application of the finite element (FE) simulation and linear elastic fracture mechanics (LEFM) to predict the onset of delamination growth. The first step of the proposed methodology is the experimental characterisation of material interlaminar fracture in pure mode I (DCB test), pure mode II (ENF test) and mixed mode I+II (MMB test). In the second step, the results of the interlaminar fracture tests are translated from load/displacement data to strain energy release rates by means of test FE simulations; thus, the critical strain energy release rate (Gc), or fracture toughness are obtained as a function of mode ratio. The third step of the methodology consists of applying FE simulations to determine the strain energy release rate (G) and mode ratio for the delamination and then comparing the result to the values of the Gc curve. The main innovative aspect of the paper is that FE simulation is used as a part of the material characterisation process; in fact, data reduction of interlaminar fracture tests is carried out by means of FE simulations. In addition, regarding the practical details of FE application to the proposed methodology, some innovative aspects are introduced, such as the analysis is carried out as a non-linear geometric problem (taken into account large displacements) and considering inside each simulation different elastic properties for the material depending on whether it is under tension or compression. These aspects and the rest of the proposed methodology are validated by the experimental results presented in the paper.
Simulation and Optimization of Logistic and Production Systems Using Discrete and Continuous Petri Nets
Authors: Macías E. Jiménez , de la Parte M. Pérez
Published: July 2004

The use of Petri nets as a tool for optimizing logistic systems of industrial supply by simulation is analyzed in this article. The application of these tools presents two basic advantages: (1) their graphic/mathematical interpretation makes them particularly useful to be applied in simulation/analysis (optimization) applications, and (2) they can be considered from a discrete/continuous point of view, as a paradigm for modeling and analyzing discrete systems or as a continuous approximation to the real discrete model. These properties are very interesting in a global simulation analysis of logistic systems because their management is usually limited by their high complexity and large dimension. Petri nets are applied to the modeling and analysis of discrete logistic systems in the classical way, using the relatively recent continuization and fluidification techniques of discrete systems for their continuous approximation. This new methodology provides results with less computational effort.
Component-Based Simulation for a Reconfiguration Study of Transitic Systems
Authors: Kindler Eugene , Coudert Thierry , Berruet Pascal
Published: July 2004

This paper is organized as follows. Part A presents the context of reconfiguring transitic systems and the main idea in implementing the decision step. It comprises sections 1 to 3. Section 3 presents an example that illustrates the concepts presented in the next sections. Parts B and C express the models and principles used to simulate transitic systems, the result of which will be helpful for choosing the new configuration. Part B focuses mainly on models. It comprises sections 4 to 6. Part C focuses mainly on simulation principles. It comprises sections 7 to 10.
Simulation as a Tool in Understanding the Concepts of Lean Manufacturing
Authors: Schroer Bernard J.
Published: July 2004

This paper presents the use of discrete event simulation to understand the concepts of lean manufacturing, including line balancing against Takt time, pull versus push manufacturing, Kanban inventory control, and process variability reduction. Several simulation models were used to evaluate the impact of these lean concepts on production, work in process, and station/operator utilization.
In Search of Modernization: The Negotiation of Social Identity in Organizational Reform
Authors: Llewellyn Nick
Published: July 2004

Based on the analysis of two short documents, this article considers how social categories, such as bureaucracy, council, business, and so on, are utilized in descriptions of project work. Specifically, it examines the locally occasioned interpretative practices that enabled a single project (in a UK local authority) to be described as modernizing the way services were delivered. In part, this involved negotiating the category ‘bureaucratic’, with the author often reasoning it would be somehow misleading to use such a category to describe the project. The article focuses on the negotiation of social categories and on the work done to present aspects of the project as ‘documents’ (Garfinkel 1967) of the authority’s category membership, as ‘in keeping’ with what would be expected of such a type. Categorization, the act of tying specific events to social types or categories, is shown to be a significant resource in accounting for the character of project work. The article adds to debates on organizational identity and public-sector reform by examining members’ commonsense knowledge of various social categories and by illustrating the role of categorization in shaping how various organizational phenomena are understood.
Means-End Frames and the Politics and Myths of Organizational Fields
Authors: Borum Finn
Published: July 2004

The processing of means-end frames is proposed as a key to understanding the reproduction and evolution of organizational fields. In lieu of regarding ‘rationalized myths’ as established social constructs that are diffused within a field, the present analysis looks into how the field constituents construct a rationalized myth, the operations through which they strive to accomplish this, and the unresolved divergences and problems tied to establishing shared understandings of central causal chains. It is argued that the social construction of means-end frames is central to preserving a shared understanding of an organizational field’s goals and the organizing principles by which these can be realized. In participating in the construction and interpretation of means-end frames the central actors reproduce and evolve the organizational field. The processing of means-end frames may contribute to both field reproduction and destabilization. Based on an analysis of the Danish hospital field, it is demonstrated how the processing of a means-end frame may serve several functions in an organizational field—the reproduction of the field, its trajectory, power structure, truces and overarching regime. But it may also contribute to field destabilization via the actors’ different interpretations and projects, the contestation of central institutions, or via unforeseeable consequences.
Re-Applying Beliefs: An Analysis of Change in the Oil Industry
Authors: Carlisle Ysanne , Baden-Fuller Charles
Published: July 2004

Beliefs and values are hard to alter; yet they strongly influence employees’ attitudes towards strategic changes. Using a longitudinal case study in the oil industry, we show how to distinguish between ideological beliefs (justified by ethical values) and mundane beliefs (substantiated by knowledge structures). We explain that the willingness of workers to participate in change was promoted by a dynamic interaction between these interdependent belief sets. More critically, we show that acceptance of change did not require a change in values, but rather a change in the way that values were applied. We develop propositions that move theory forward and point to future directions for research.
The Anatomy and Isometry of Themedial Patellofemoral Ligament
Authors: Steensen Robert N. , Dopirak Ryan M. , Mcdonald William G.
Published: July 2004

Background

Several techniques have been described for reconstruction of the medial patellofemoral ligament. However, the isometry of the medial patellofemoral ligament has not been studied.

Purpose

To define the anatomy and isometry of the medial patellofemoral ligament.

Study Type

Cadaveric study.

Methods

The authors dissected the medial patellofemoral ligament in 11 cadaveric knees and recorded its anatomic relationships. They evaluated the isometry of the medial patellofemoral ligament by obtaining measurements between various anatomic pairings at certain fixed angles of knee flexion.

Results

During knee flexion from 0° to 90°, the portion of the medial patellofemoral ligament from the inferior patellar attachment to the superior femoral attachment was nearly isometric, demonstrating an average change in length of only 1.1 mm. Statistical analysis showed the superior femoral attachment to be most significant in determining isometric behavior.

Conclusions

The most isometric portion of the medial patellofemoral ligament is the inferior portion of its patellar attachment extending to the superior portion of its femoral attachment, with the superior femoral attachment having the most notable influences on isometry.

Clinical Relevance

This study provides a detailed description of the anatomy of the medial patellofemoral ligament, as well as an evaluation of the isometric behavior of the ligament. Application of these data during reconstruction of the medial patellofemoral ligament may help to optimize patellofemoral stability.
Stability of Acromioclavicular Joint Reconstruction
Authors: Deshmukh Ashwin V. , Wilson David R. , Zilberfarb Jeffrey L. , Perlmutter Gary S.
Published: July 2004

Background

Despite reports of excellent results with the Weaver-Dunn coracoacromial ligament transfer, many authors recommend augmenting the transfer with supplemental fixation. The authors of this study sought to determine whether there is a biomechanical basis for this assertion and which augmentative method, if any, most closely restored acromioclavicular motion to normal.

Hypothesis

Augmentative coracoclavicular fixation provides better restoration of normal acromioclavicular joint laxity and an increased failure load when compared with the Weaver-Dunn reconstruction alone.

Study Design

Controlled laboratory cadaveric study.

Methods

Native acromioclavicular joint motion was measured using an infrared optical measurement system. Acromioclavicular and coracoclavicular ligaments were then cut, and 1 of 6 reconstructions was performed: Weaver-Dunn, suture cerclage, and 4 different suture anchors. Acromioclavicular joint motion was reassessed, a cyclic loading test was performed, and the failure load was recorded.

Results

After Weaver-Dunn reconstruction, mean anteroposterior laxity increased from 8.8 ± 2.9 mm in the native state to 41.9 ± 7.6 mm (P≤ .01), and mean superior laxity increased from 3.1 ± 1.5 mm to 13.6 ± 4.4 mm (P≤ .01). Weaver-Dunn reconstructions failed at a lower load (177 ± 9 N) than all other reconstructions (range, 278-369 N) (P≤ .05). Reconstruction using augmentative fixation allowed less acromioclavicular motion than Weaver-Dunn reconstruction (P≤ .05) but more motion than the native ligaments (P≤ .05). Specifically, mean superior laxity after reconstruction ranged between 6.5 and 9.0 mm compared with the native ligaments (3.1 ± 1.5 mm) and the Weaver-Dunn reconstructions (13.6 ± 4.4 mm). Mean anteroposterior laxity after the reconstructions tested ranged between 21.8 and 33.2 mm, compared with the native ligaments (8.8 ± 2.9 mm) and the Weaver-Dunn reconstructions (41.9 ± 7.6 mm).

Conclusion

Although none of the augmentative methods tested restored acromioclavicular stability to normal, all proved superior to the Weaver-Dunn reconstruction alone.

Clinical Relevance

This study suggests that when performing acromioclavicular reconstruction, supplemental fixation should be used because it provides more stability and pull-out strength than the Weaver-Dunn reconstruction alone.
Hyperconcavity of the Lumbar Vertebral Endplates in the Elite Football Lineman
Authors: Moorman Claude T. , Johnson David C. , Pavlov Helene , Barnes Ronnie , Warren Russell F. , Speer Kevin P. , Guettler Joseph H.
Published: July 2004

Background

Hyperconcavity of the vertebral endplates is a previously unreported radiologic phenomenon.

Purpose

To analyze hyperconcavity of the vertebral endplates with expansion of the disk space in pre–National Football League lineman and to determine its clinical significance.

Study Design

Descriptive anatomical study.

Methods

Over a 2-year period (1992-1993), 266 elite football linemen were evaluated at the National Football League scouting combine held in Indianapolis, Indiana. Evaluation focused on the lumbosacral spine and included history, physical examination, and lateral radiographs. Measurements were taken of all the vertebral endplate defects of involved vertebrae and compared with an age-matched control group of 110 patients.

Results

The analyzed data revealed the following: (1) hyperconcavity of the vertebral endplates appeared as a distinct entity in a high percentage of pre–National Football League lineman (33%) compared with age-matched controls (8%), (2) there was a trend toward a lower incidence of lumbosacral spine symptoms in those players who displayed hyperconcavity of the vertebral endplates (16%) versus those who did not (25%), and (3) when hyperconcavity of the vertebral endplates was present, all 5 lumbosacral disk spaces were commonly affected.

Conclusions

Hyperconcavity of the vertebral endplates and hypertrophy of the disk space are likely adaptive changes occurring over time in response to the repetitive high loading and axial stress experienced in football line play.
Open Bankart Repair versus Arthroscopic Repair with Transglenoid Sutures or Bioabsorbable Tacks for Recurrent Anterior Instability of the Shoulder
Authors: Freedman Kevin B. , Smith Adam P. , Romeo Anthony A. , Cole Brian J. , Bach Bernard R.
Published: July 2004

Background

In published comparative studies, it remains unknown if arthroscopic techniques for performing Bankart repair for anterior shoulder instability equal the success of open repair.

Hypothesis

The current literature supports a lower rate of recurrent instability after open Bankart repair compared to arthro-scopic repair with bioabsorbable tacks or transglenoid sutures.

Study Design

Meta-analysis.

Methods

A Medline search identified all randomized controlled trials or cohort studies that directly compared open repair to arthroscopic techniques of Bankart repair for traumatic, unilateral, recurrent anterior instability. Data collected from each study included patient demographics, surgical technique, rehabilitation, outcome, and complications.

Results

Six studies met all inclusion criteria. There were 172 patients in the arthroscopic group (90 patients with transglenoid sutures, 77 patients with arthroscopic tacks, and 5 patients with suture anchors) and 156 patients in the open group. The groups were similar in demographic characteristics. When comparing the arthroscopic to the open group, there was a significantly higher rate of recurrent dislocation (12.6% vs 3.4%; P = .01) and total recurrence (recurrent dislocation or subluxation) (20.3% vs 10.3%; P = .01). In addition, there was a higher proportion of patients with an excellent or good postoperative Rowe score in the open group (88%) than in the arthroscopic group (71%) (P = .01).

Conclusions

Arthroscopic Bankart repair using transglenoid sutures or bioabsorbable tacks results in a higher rate of recurrence of instability compared to open techniques. Studies comparing open repair to newer arthroscopic techniques using suture anchor fixation and capsular plication are necessary.
Elastic-Plastic Stress Analysis of Thermoplastic Matrix-Woven Fiber Composite Laminated Plates Under In-plane Loading
Authors: Yapici Ahmet
Published: July 2004

The mechanical performance of composite laminated plate with different loading conditions was investigated. Composite structures consisting of woven galvanized wire as a fiber and F2.12 low density polyethylene (LDPE) as a thermoplastic matrix were manufactured by hot-press moulding. The mechanical properties were experimentally determined. The effect of orientation angle and symmetric-antisymmetric structure was investigated. An elastic-plastic numerical solution was carried out using Finite Element Technique (FEM) for some iteration numbers. Residual stresses and expansion of plastic zone have been illustrated in tables and figures.
Static Analysis of Bimodulus Laminated Composite Plates Subjected to Mechanical Loads Using Higher-Order Shear Deformation Theory
Authors: Ganapathi M. , Patel B. P. , Lele A. V.
Published: July 2004

Here, static flexural analysis of laminated composite plates of bimodulus materials subjected to mechanical loading is carried out. The formulation is based on higher-order theory that accounts for the transverse shear and transverse normal deformations, and incorporates through the thickness approximations of the in-plane displacements. The governing equations obtained using the principle of minimum potential energy are solved through the finite element approach. The results obtained here are compared with those of the theory without thickness stretch\contraction terms and the first-order one. The combined influence of higher-order shear deformation, plate geometry, lay-up and ply-angle on the displacements/stresses and neutral surface locations of bimodulus composite laminate is examined.
Study on Numerical Simulation and Experiment of Lightguide Plate in Injection Molding
Authors: Shen Y. K. , Wu W. Y. , Yang S. Y. , Jian H. M. , Chen C -C. A.
Published: July 2004

This paper presents the application of injection molding of wedge-shaped plates for lightguiding application. This paper discusses the influence of processing parameters on injection molding. The filling stages of lightguide plate for mold flow simulation (3D, midplane) are analyzed. The numerical simulation of mold filling process is based on the concept of control volume finite element method. The hot plastic melt touches the cold wall that forms the solid layer, a solid-liquid interface moves and a two-phase flow exists. The enthalpy model is used to predict this interface in the two-phase flow problem. The experiments carry out short-shots process to compare with numerical simulation. The experiments also indicate the pressure distribution at thin and thick ends of lightguide plate using pressure transducers. The results show that the results of 3D filling situation is close to those from experiments. The melt front progress of 3D numerical simulation is predicted more accurately than midplane numerical simulation.
Development of Embedded Sensor Models in Composite Laminates for Structural Health Monitoring
Authors: Kim Heung Soo , Ghoshal Anindya , Chattopadhyay Aditi , Prosser William H.
Published: July 2004

A framework is developed to study the transient analysis of composite laminated plates with embedded discrete and continuous sensors in the presence of delaminations. The computational modeling involves development of a finite element scheme using an improved layerwise laminate theory to model laminates of arbitrary thickness. Parametric studies are conducted using laminated plates with both embedded sensors and continuous sensor architecture. The response of the plates under both low-frequency vibration and high-frequency acoustic emission are investigated. The effects on plate displacement and sensor outputs due to delaminations are studied. The scattering of the acoustic emission caused by the presence of delaminations is also investigated. It is expected that the developed model would be a useful tool in simulation studies aimed at characterizing the presence of delaminations in composite laminated structures.
Accession and Social Policy: The Case of the Czech Republic
Authors: Potucek Martin
Published: July 2004

This paper assesses the place of EU accession among the determinants of the changes taking place in the Czech social policy after 1989. Compulsory social and health insurance were re-introduced in the early 1990s, along with a guaranteed subsistence minimum for all, and an institutionalized state employment policy. This paper argues that EU-derived policies have had only a limited impact on Czech social-policy reform, focusing mostly on institution building. This phenomenon can be attributed to the apparent discrepancy between Copenhagen criteria of accession (1993) and the Lisbon Strategy, which was accepted as a policy guideline in 2002. Thus, the main concept able to explain Czech social-policy development after 1989 is that of institutional and behavioural path dependency as the country exhibited resistance to change coupled with a strong adherence to the Bismarckian, corporatist, welfare state. This makes the Czech Republic a special case compared to the other Visegrad countries, where the pressure from neo-liberal public-policy concepts of the World Bank and the International Monetary Fund found its expression in the introduction of more residual social policies.