bluuebunny/crossref_metadata_2025 huggingface dataset:
Predation of seabirds by invasive rats: multiple indirect consequences for invertebrate communities
Authors: Towns David R. , Wardle David A. , Mulder Christa P. H. , Yeates Gregor W. , Fitzgerald Brian M. , Richard Parrish G. , Bellingham Peter J. , Bonner Karen I.
Published: November 2008

Invasive species are a global problem but most studies have focused on their direct rather than indirect ecological effects. We studied litter and soil‐inhabiting invertebrate communities on 18 islands off northern New Zealand, to better understand the indirect ecological consequences of rat (Rattus) invasion. Nine islands host high densities of burrowing procellariid seabirds that transport large amounts of nutrients from the ocean to the land. The other nine have been invaded over the past 50–150 years by rat species that have severely reduced the density of seabirds by preying on eggs and chicks. Invaded islands had lower densities of seabird burrows but deeper forest litter than did the uninvaded islands, indicative of rats reducing disturbance effects of seabirds. However, despite deeper litter on the invaded islands, eight of the 19 orders of invertebrates that we measured were significantly less abundant on invaded islands. Furthermore, three soil‐inhabiting micro‐invertebrate groups that we measured were significantly less abundant on invaded islands. These differences probably result from rats thwarting transfer of resources by seabirds from the ocean to the land. We also investigated community‐level properties of each of three test groups of invertebrates (minute land snails, spiders and soil nematodes) to illustrate this process. Spiders were equally abundant on both groups of islands, but showed lower species richness on the invaded islands. The other two groups showed no difference in species richness with island invasion status, but were more abundant on uninvaded islands. Reduced abundance of soil nematodes on invaded islands provides strong evidence of indirect consequences of seabird reduction by rats, because nematodes are unavailable to rats as prey. We predict that if rats are eradicated from islands, components of below‐ground invertebrate dependent on seabird‐mediated soil conditions may take considerable time to recover because they require subsequent seabird recolonisation.
Oxidative stress of the newborn in the pre‐ and postnatal period and the clinical utility of melatonin
Authors: Gitto Eloisa , Pellegrino Salvatore , Gitto Placido , Barberi Ignazio , Reiter Russel J.
Published: November 2008

Abstract: Newborns, and especially those delivered preterm, are probably more prone to oxidative stress than individuals later in life. Also during pregnancy, increased oxygen demand augments the rate of production of reactive oxygen species (ROS) and women, even with normal pregnancies, experience elevated oxidative stress and lipid peroxidation compared with nonpregnant women. Also, there appears to be an increase in ROS generation in the placenta of pre‐eclamptic women. In comparison with healthy adults, newborn infants have lower levels of plasma antioxidants such as vitamin E, β‐carotene, and sulphydryl groups, lower levels of plasma metal binding proteins including ceruloplasmin and transferrin, and reduced activity of erythrocyte superoxide dismutase. This review summarizes conditions of newborns where there is elevated oxidative stress. Included in this group of conditions is asphyxia, respiratory distress syndrome and sepsis and the review also summarizes the literature related to clinical trials of antioxidant therapies and of melatonin, a highly effective antioxidant and free radical scavenger. The authors document there is general agreement that short‐term melatonin therapy may be highly effective and that it has a remarkably benign safety profile, even when neonates are treated with pharmacological doses. Significant complications with long‐term melatonin therapy in children and adults also have not been reported. None of the animal studies of maternal melatonin treatment or in postnatal life have shown any treatment‐related side effects. The authors conclude that treatment with melatonin might result in a wide range of health benefits, improved quality of life and reduced healthcare costs and may help reduce complications in the neonatal period.
VEGF and MVD expression in sinus augmentation with autologous bone and several graft materials
Authors: Boëck‐Neto RJ , Artese L , Piattelli A , Shibli JA , Perrotti V , Piccirilli M , Marcantonio Jr E
Published: November 2008

Objective:  The aim of this study was to assess vascular endothelial growth factor (VEGF) expression and microvessel density (MVD) in maxillary sinus augmentation with autogenous bone and different graft materials for evaluating their angiogenic potential.

Methods:  Biopsies were harvested 10 months after sinus augmentation with a combination of autogenous bone and different graft materials: hydroxyapatite (HA, n = 6 patients), demineralized freeze‐dried bone allograft (DFDBA, n = 5 patients), calcium phosphate (CP, n = 5 patients), Ricinus communis polymer (n = 5 patients) and control group – autogenous bone only (n = 13 patients).

Results:  In all the samples, higher intensities of VEGF expression were prevalent in the newly formed bone, while lower intensities of VEGF expression were predominant in the areas of mature bone. The highest intensity of VEGF expression in the newly formed bone was expressed by HA (P < 0.001) and CP in relation to control (P < 0.01) groups. The lowest intensities of VEGF expression in newly formed bone were shown by DFDBA and polymer groups (P < 0.05). When comparing the different grafting materials, higher MVD were found in the newly formed bone around control, HA and CP (P < 0.001).

Conclusion:  Various graft materials could be successfully used for sinus floor augmentation; however, the interactions between bone formation and angiogenesis remain to be fully characterized.
A role for the substance P/NK‐1 receptor complex in cell proliferation and apoptosis in oral lichen planus
Authors: González Moles MA , Esteban F , Ruiz‐Ávila I , Gil Montoya JA , Brener S , Bascones‐Martínez A , Muñoz M
Published: November 2008

Objectives:  To determine whether substance P (SP) and NK‐1 receptor (NK‐1R) are expressed in oral lichen planus (OLP) and are related to cell proliferation and apoptosis in this disease.

Material and methods:  Tissue samples from 50 OLP patients and 26 healthy controls were studied. Immunohistochemistry was performed with anti‐SP, anti‐NK‐1R, anti‐ki‐67 and anti‐caspase‐3 monoclonal antibodies and the clinical and pathological data of the OLP patients were evaluated.

Results:  With the exception of NK‐1R expression in epithelial cell membrane and cytoplasm, all markers were more frequently present in OLP patients than in controls (P < 0.05). Higher cytoplasmatic expression of NK‐1R was associated with higher epithelial expression of caspase‐3 (P < 0.05). Higher epithelial expression of NK‐1R and SP was associated with higher suprabasal and basal epithelial expression of ki‐67 (P < 0.05 and P < 0.005, respectively).

Conclusions:  Actions of the SP/NK‐1R complex may contribute to the immune disorder underlying OLP and trigger stimuli to induce cell proliferation. These results indicate that this complex might play a role in the malignant transformation of OLP.
Diagnostic approach for suspected pseudoallergic reaction to food ingredients
Authors: Reese Imke , Zuberbier Torsten , Bunselmeyer Britta , Erdmann Stephan , Henzgen Margot , Fuchs Thomas , Jäger Lothar , Kleine‐Tebbe Jörg , Lepp Ute , Niggemann Bodo , Raithel Martin , Saloga Joachim , Vieths Stephan , Werfel Thomas
Published: November 2008

Chronic urticaria, recurrent angioedema and non‐allergic asthma have all been associated with pseudoallergic reactions to food ingredients. For atopic dermatitis and diseases of the gastrointestinal tract, this association is controversial. Pseudoallergic reactions can be elicited by additives as well as by natural food ingredients. An altered histamine metabolism may be associated with pseudoallergy.

Acute urticaria or a short episode of angioedema is not an indication for exhaustive evaluation. If basic diagnostic screening is negative in chronic urticaria, a low‐pseudoallergen diet can be considered. Skin and serological tests are not objective diagnostic parameters for pseudoallergic reactions. The severity of symptoms should be documented while the patient is on a low‐pseudoaller‐gen diet.

Oral provocation with additives leads to reproducible symptoms only in a few cases. Therefore, if a low‐pseudoallergen diet brings improvement, the patient is then exposed to a pseudoallergen‐rich "super meal". After a positive reaction to the "super meal" the challenge with additives takes place in the form of collective group exposition. When the patient has asthma or a history of anaphylac‐toid reactions, testing with individual substances in carefully increasing dosages is required.

The suspicion of adverse reactions against histamine can be confirmed by a challenge with histamine dihydrochloride. In the case of respiratory symptoms, provocation by inhalation should be considered. Objectifying symptoms especially in gastrointestinal diseases is mandatory and should include double‐blind placebo‐controlled food challenge, if possible.
Never the Twain Shall Meet? Integrating Chinese and Western Management Research
Authors: Leung Kwok
Published: November 2008

This commentary offers several directions for the development of Chinese management research based on the penetrating analyses provided by Barney and Zhang (2009) and Whetten (2009). First and foremost, Chinese management researchers can develop novel, seminal ideas and theories that are not necessarily tied to the Chinese cultural context but are applicable in diverse cultural contexts. The success of this approach depends on the merit of the ideas and theories proposed. A fusion, or combined emic–etic approach, can also be attempted, which integrates elements from Western and indigenous theories. Finally, the synergistic approach involves a dynamic interplay of Chinese and Western management research, which will eventually lead to innovative, culture-general theories. This article argues that all three approaches should be emphasized in Chinese management research.
Small‐Sample Equating Using a Synthetic Linking Function
Authors: Kim Sooyeon , Von Davier Alina A. , Haberman Shelby
Published: November 2008

This study addressed the sampling error and linking bias that occur with small samples in a nonequivalent groups anchor test design. We proposed a linking method called the synthetic function, which is a weighted average of the identity function and a traditional equating function (in this case, the chained linear equating function). Specifically, we compared the synthetic, identity, and chained linear functions for various‐sized samples from two types of national assessments. One design used a highly reliable test and an external anchor, and the other used a relatively low‐reliability test and an internal anchor. The results from each of these methods were compared to the criterion equating function derived from the total samples with respect to linking bias and error. The study indicated that the synthetic functions might be a better choice than the chained linear equating method when samples are not large and, as a result, unrepresentative.
An Empirically Based Method of Q‐Matrix Validation for the DINA Model: Development and Applications
Authors: De La Torre Jimmy
Published: November 2008

Most model fit analyses in cognitive diagnosis assume that a Q matrix is correct after it has been constructed, without verifying its appropriateness. Consequently, any model misfit attributable to the Q matrix cannot be addressed and remedied. To address this concern, this paper proposes an empirically based method of validating a Q matrix used in conjunction with the DINA model. The proposed method can be implemented with other considerations such as substantive information about the items, or expert knowledge about the domain, to produce a more integrative framework of Q‐matrix validation. The paper presents the theoretical foundation for the proposed method, develops an algorithm for its practical implementation, and provides real and simulated data applications to examine its viability. Relevant issues regarding the implementation of the method are discussed.
Determining Hydraulic Conductivity Using Pumping Data from Low‐Flow Sampling
Authors: Robbins Gary A. , Aragon‐Jose Alejandra T. , Romero Andres
Published: November 2008

Hydraulic conductivity values computed using the steady‐state discharge and drawdown attained while low‐flow sampling were evaluated to determine if they were equivalent to those determined from slug testing. Based on testing 12 wells, it was found that the results were statistically equivalent. Conductivity values computed using low‐flow sampling parameters were also evaluated as to their reproducibility in actual practice by analyzing consultant data for three wells sampled over three quarterly monitoring periods by four field technicians. The results were found to be reproducible within about a factor of 2 or better. Since the method is based on only one pair of parameters, diligence is required in attaining steady state and in accurately measuring the flow rate and drawdown. Conductivity values computed using this approach can enhance the use of low‐flow data gathered in water quality sampling, avoid the need for slug testing in a subsequent phase of investigation, and help reduce the cost of characterizing sites when multilevel samplers are used. Given the practical range of discharge in low‐flow sampling, the method was found to be applicable at conductivity values somewhat greater than 10−6 cm/s. Given the typical accuracy of water level meters and pressure transducers and a maximum discharge of 1 L/min, as mandated by regulatory guidance, the method has a calculated upper conductivity limit in the range of 10−3 to 10−2 cm/s.
Numerical Modeling of Atoll Island Hydrogeology
Authors: Bailey R.T. , Jenson J.W. , Olsen A.E.
Published: November 2008

We implemented Ayers and Vachers’ (1986) inclusive conceptual model for atoll island aquifers in a comprehensive numerical modeling study to evaluate the response of the fresh water lens to selected controlling climatic and geologic variables. Climatic factors include both constant and time‐varying recharge rates, with particular attention paid to the effects of El Niño and the associated drought it brings to the western Pacific. Geologic factors include island width; hydraulic conductivity of the uppermost Holocene‐age aquifer, which contains the fresh water lens; the depth to the contact with the underlying, and much more conductive, Pleistocene karst aquifer, which transmits tidal signals to the base of the lens; and the presence or absence of a semiconfining reef flat plate on the ocean side. Sensitivity analyses of steady‐steady simulations show that lens thickness is most strongly sensitive to the depth to the Holocene‐Pleistocene contact and to the hydraulic conductivity of the Holocene aquifer, respectively. Comparisons between modeling results and published observations of atoll island lens thicknesses suggest a hydraulic conductivity of approximately 50 m/d for leeward islands and approximately 400 m/d for windward islands. Results of transient simulations show that lens thickness fluctuations during average seasonal conditions and El Niño events are quite sensitive to island width, recharge rate, and hydraulic conductivity of the Holocene aquifer. In general, the depletion of the lens during drought conditions is most drastic for small, windward islands. Simulation results suggest that recovery from a 6‐month drought requires about 1.5 years.
Bringing the In‐Between Back in: Foreign Policy in Global Environmental Politics
Authors: Harris Paul G.
Published: November 2008

Many environmental problems are transnational in their causes, consequences, and/or solutions. The increasing pace of global environmental destruction suggests that research on policies to address these problems has proved to be inadequate to the task. One possible way to enhance our understanding of global environmental politics and policy is to look more carefully at what goes on between and across the international and domestic aspects of it: to look at environmental foreign policy. This article describes foreign policy in the context of global environmental politics and discusses the potential utility of foreign policy analysis to help scholars and policy makers to better explore, comprehend, and possibly mitigate the human impact on the environment. Examples are drawn from the cases of China, Japan, and the United States.
Emergency Judgment: Carl Schmitt, John Locke, and the Paradox of Prerogative
Authors: Casson Douglas
Published: November 2008

Faced with an unsettling expansion of executive emergency power in the United States, scholars have turned to the thought of Carl Schmitt to shed light on constitutional liberalism. Yet the resources for responding to Schmitt can be found in the very tradition that he urges his readers to overcome. Locke recognized what many liberal thinkers since have been hesitant to admit. Fixed laws can help restrain prerogative to a certain extent but cannot transform the irrational and unpredictable nature of political life nor eliminate the discretionary power necessary to respond to it. Consequently, the most important and most effective restraint on executive discretionary power is not legal but political. Both the judgment of the executive and the judgment of the people are essential extralegal elements of the constitutional order.
Political Regimes, Bureaucracy, and Scientific Productivity
Authors: Lapuente Victor , Fernández‐Carro Remo
Published: November 2008

Can a scientist trust that the government is going to pay him or her fairly? In the science–government relationship, an incumbent may be better off if he or she does not provide—or does not provide a fair pay to public scientists. We propose a simple game‐theoretic model for understanding the trust problem in the relationship between governments and scientists. The model shows how with reliable governments (democracies), bureaucratic contracts (e.g., secure tenure) are not optimal since they have low‐powered incentives (in contrast to the high‐powered private‐sector type of contracts) and run against scientists' responsiveness to government demands. However, with nonreliable governments (dictatorships), bureaucratic contracts are second‐best solutions because they protect scientists against the possibility of governments' misbehavior (i.e., ex post opportunistic defections, such as canceling research programs overnight). An empirical analysis confirms the predictions: bureaucratic contracts enhance scientific productivity with nonreliable governments (dictatorships) but hamper scientific productivity with reliable governments (democracies).
Defining Involvement of County Commissioners in the Budget Formulation Process
Authors: Modlin Steve
Published: November 2008

Prescribing a normative budget theory to describe the actions of budgetary actors has proved to be a major challenge for scholars. The number of internal and external influences that contribute to the decision‐making process are numerous. The conundrum deepens when applied to local governments. Previous research surrounding the intervention of actors within the process has focused mainly on the strong executive form of municipal government. This article identifies characteristics that lead to more involvement by county commissioners in the commission‐manager form of government. State legislation that drives the process along with the responsibility of formulating county budgets left to that of the county manager are factors that limit the discretion within decision making, but characteristics such as party identification, commission board size, age, and occupation all play a role in the level of commissioner involvement.
Looking for Law in All the Wrong Places? Foreign Law and Support for the U.S. Supreme Court
Authors: Curry Brett , Miller Banks
Published: November 2008

References to foreign legal judgments in several recent Supreme Court decisions have given rise to substantial legal and political controversy. While those debates have largely focused on normative matters, we utilize an experimental design that presents media portrayals of Court decisions to assess the possible implications of this issue for the Court and its legitimacy with the public. Our results suggest that, should the Court continue to utilize this practice, it could result in some erosion of public support for the Court as an institution. Further, we find that this effect has the potential to be particularly powerful in structuring the opinions of citizens who are less knowledgeable about government and the Court.
Régime de retraite à cotisations définies notionnelles assorti d’un fonds de réserve public dans les économies à la population vieillissante: application au cas du Japon
Authors: Lu Bei , Mitchell Olivia S. , Piggott John
Published: November 2008

Résumé  Plusieurs pays, tant développés qu’en voie de développement, ont récemment instauré des régimes à cotisations définies notionnelles (CDN) dans le cadre d’une réforme des pensions de vieillesse. Le régime à CDN est essentiellement un régime de retraite à cotisations définies non financé par capitalisation. Les cotisations y sont créditées d’un «taux de rendement» liéà l’augmentation globale de la masse salariale et l’on tient la comptabilité des montants qui s’accumulent sur des comptes individuels. Les prestations prennent la forme d’une rente fondée sur le taux de mortalité attendu de chaque cohorte partant successivement en retraite. S’il est possible, en situation d’équilibre démographique, d’assimiler les régimes à CDN à des régimes par répartition correctement calibrés, les deux modèles divergent lorsque des mutations démographiques interviennent. On étudie dans le présent article les principales implications actuarielles et économiques des différents dispositifs à CDN possibles, en se concentrant particulièrement sur le Japon, l’économie dont la population connaît le vieillissement le plus rapide au monde. Nous examinons le rôle potentiel d’un fonds de réserve des retraites lors du passage à un régime à CDN et montrons qu’un tel fonds peut servir à atténuer l’impact du vieillissement démographique. Enfin, nous indiquons que des pays comme le Japon pourraient choisir d’utiliser des réserves accumulées par les régimes de retraite dans le passé pour favoriser un passage sans heurt à un régime à CDN.
Une transition souple entre le marché du travail et les pensions de retraite: un nouveau modèle pour des sociétés vieillissantes?
Authors: Bredt Stephan
Published: November 2008

Résumé  Le relèvement de l'âge ouvrant droit à pension dûà l'augmentation de l'espérance de vie suscite une forte résistance politique. Pour des raisons tenant à la santé et au marché du travail, certains se trouveront toujours dans l'impossibilité de réunir toutes les conditions d'octroi d'une pension. Même si les possibilités de retraite anticipée ne sont pas limitées, la marge de manœuvre pour accumuler des revenus permettant de financer une retraite anticipée est souvent étroitement définie. En conséquence, les personnes qui prennent une retraite anticipée ne peuvent pas compenser le manque à gagner. Face à la tendance générale de relever l'âge ouvrant droit à pension, une autre proposition de réforme est actuellement étudiée par les responsables allemands de la politique sociale. Il s'agirait de laisser le choix de l'âge de la retraite (à partir de 60 ans), de ne pas limiter l'accumulation de droits supplémentaires à pension pendant la période d'activité, de procéder à des déductions actuarielles en cas de retraite anticipée et de tenir compte de l'espérance de vie dans l'ajustement des pensions. Cette solution soulage le régime public de pensions financièrement, renforce l'attrait que présentent les personnes du troisième âge sur le marché du travail, permet de choisir la date de la retraite et réduit la résistance politique opposée à la réforme des pensions. L'effet sur le marché du travail pour les personnes âgées doit encore être examiné.
Auf fiktiven Konten basierende Renten mit staatlichen Reservefonds in alternden Volkswirtschaften: Das Beispiel Japans
Authors: Lu Bei , Mitchell Olivia S. , Piggott John
Published: November 2008

Auszug

Mehrere Industrie‐ und Entwicklungsländer haben sich in jüngster Zeit für einen Ansatz mit Festbeiträgen auf fiktiven Konten (NDC —Notional Defined Contribution) für ihre Altersrentenreform entschieden. NDC ist im Wesentlichen ein nicht vorfinanziertes Festbeitragsrentensystem, in dem Beiträge mit einer Verzinsung gutgeschrieben werden, die sich auf das Gesamtwachstum der Lohnsumme bezieht, und in dem individuelle Kontoerträge in einem Buchhaltungssystem geführt werden. Auszahlungen werden je nach der erwarteten Sterblichkeit der jeweils in den Ruhestand tretenden Kohorte auf Jahre umgerechnet. NDC‐Pläne lassen sich bei demografischem Gleichgewicht mit gut abgestimmten Plänen nach dem Umlageverfahren gleichsetzen, aber die zwei Paradigmen unterscheiden sich, sobald sich demografische Veränderungen ergeben. Der vorliegende Beitrag untersucht die wichtigen versicherungsmathematischen und wirtschaftlichen Folgen der Alternative mit NDC‐Regeln unter besonderer Berücksichtigung des Beispiels Japan, der am schnellsten alternden Wirtschaft der Welt. Wir prüfen die mögliche Rolle von Rentenreserven beim Übergang zu einem NDC‐System, und wir zeigen, dass sie verwendet werden können, um die Auswirkungen des demografischen Übergangs zu einer älteren Gesellschaft abzufedern. Schließlich zeigen wir auch, dass Länder wie Japan in der Vergangenheit angesammelte Rentenreserven verwenden können, um den Übergang zu einem NDC‐System zu erleichtern.
Ledermanniella pollardiana sp. nov. (Podostemaceae) from western Cameroon
Authors: Cheek Martin , Ameka Gabriel
Published: November 2008

Ledermanniella pollardiana Cheek & Ameka (Podostemaceae) is described as a new species from western Cameroon and its morphological affinities and conservation status are assessed.
Choleretic effect of inchinkoto, a herbal medicine, on livers of patients with biliary obstruction due to bile duct carcinoma
Authors: Watanabe Shinya , Yokoyama Yukihiro , Oda Koji , Kokuryo Toshio , Shoda Junichi , Okada Kosuke , Utsunomiya Hirotoshi , Nagino Masato
Published: November 2008

Aim:  To investigate the choleretic effects of inchinkoto (ICKT) on livers of patients with biliary obstruction due to bile duct carcinoma.

Methods:  Twenty‐seven patients with bile duct carcinoma who were due to undergo biliary drainage and subsequent major hepatectomy were randomly assigned to preoperative ICKT (n = 13) or untreated (n = 14) groups. ICKT was administered from the day of admission until one day before surgery. Changes in bile constituents, expression of multidrug resistance‐associated protein (MRP) 2, MRP3 and MRP4 in the liver, and the incidence of postoperative complications were included as end‐points.

Results:  The biliary concentration of total bilirubin was significantly increased after administration of ICKT (23.7 ± 2.8 mg/dL before ICKT; 34.0 ± 4.0 mg/dL after ICKT, P < 0.05). The biliary concentration of total bile acids was also significantly increased. Protein levels of MRP2 and MRP3 in the crude plasma membrane fraction of livers of treated patients were significantly higher than those without treatment. MRP2 staining in the livers of patients without ICKT treatment was weak and diffuse around the bile canaliculi, whereas staining in patients with ICKT treatment was strong and restricted to the bile canaliculi.

Conclusion:  ICKT exerts a choleretic effect on the livers of patients with biliary obstruction. This beneficial effect was associated with increased expression of MRP2. ICKT thus has therapeutic potential for treatment for obstructive cholestasis due to bile duct carcinoma.
Successful treatment of Epstein–Barr Virus‐associated haemophagocytic syndrome arising after living donor liver transplantation
Authors: Zhang Mingman , Guo Chunbao , Yan Lunan , Pu Conglun , Li Yingcun , Kang Quan , Ren Zhimei , Jin Xianqing
Published: November 2008

A 6‐year‐old girl received an orthotopic liver transplant secondary to liver failure of unknown etiology. Several days after liver transplantation, she developed pancytopenia and Epstein –Barr Virus (EBV)‐positive seroconvert after transplant. Taking of medical history to provide evidence of pancytopenia correlated with EBV infection after transplant. Bone‐marrow biopsy was carry out to confirm haemophagocytic syndrome (HPS). Laboratory investigations, including blood routine count, microscopic blood film examination, serum ferritin concentration, and liver function tests were carried out starting from the first day of suspected HPS infection, continuing until 15 weeks post‐infection. Liver transplantation followed with a combination of cyclosporin A, corticosteroids, VP‐16, and supportive strategies.
Postsynaptic action of GABA in modulating sensory transmission in co‐cultures of rat carotid body via GABAA receptors
Authors: Zhang Min , Clarke Katherine , Zhong Huijun , Vollmer Cathy , Nurse Colin A.
Published: November 2008

GABA is expressed in carotid body (CB) chemoreceptor type I cells and has previously been reported to modulate sensory transmission via presynaptic GABAB receptors. Because low doses of clinically important GABAA receptor (GABAAR) agonists, e.g. benzodiazepines, have been reported to depress afferent CB responses to hypoxia, we investigated the potential contribution of GABAAR in co‐cultures of rat type I cells and sensory petrosal neurones (PNs). During gramicidin perforated‐patch recordings (to preserve intracellular Cl−), GABA and/or the GABAA agonist muscimol (50 μm) induced a bicuculline‐sensitive membrane depolarization in isolated PNs. GABA‐induced whole‐cell currents reversed at ∼−38 mV and had an EC50 of ∼10 μm (Hill coefficient =∼1) at −60 mV. During simultaneous PN and type I cell recordings at functional chemosensory units in co‐culture, bicuculline reversibly potentiated the PN, but not type I cell, depolarizing response to hypoxia. Application of the CB excitatory neurotransmitter ATP (1 μm) over the soma of functional PN induced a spike discharge that was markedly suppressed during co‐application with GABA (2 μm), even though GABA alone was excitatory. RT‐PCR analysis detected expression of GABAergic markers including mRNA for α1, α2, β2, γ2S, γ2L and γ3 GABAAR subunits in petrosal ganglia extracts. Also, CB extracts contained mRNAs for GABA biosynthetic markers, i.e. glutamate decarboxylase (GAD) isoforms GAD 67A,E, and GABA transporter isoforms GAT 2,3 and BGT‐1. In CB sections, sensory nerve endings apposed to type I cells were immunopositive for the GABAAR β subunit. These data suggest that GABA, released from the CB during hypoxia, inhibits sensory discharge postsynaptically via a shunting mechanism involving GABAA receptors.
Design Modifications and Optimization of a Commercially Available Knee Simulator
Authors: Kretzer J. P. , Jakubowitz E. , Hofmann K. , Heisel C. , Kleinhans J. A. , Thomsen M.
Published: November 2008

To determine the wear behavior of knee endoprostheses, implants are tested in knee simulators before being introduced to the market. Implants may undergo mechanical failure and wear debris is generated. The magnitude and morphology of this debris are determined to gain information about its biological reactivity. In this study, we describe the modifications made to the AMTI multistation knee simulator. The simulator is not capable to ensure a medially biased load distribution as required per ISO 14243, and therefore the usage of the simulator is limited. Thus, simulator modifications were made to implement a wear test as outlined in ISO 14243, and to improve both user-friendliness of operation and cost of simulation. In particular, this involved modifying the implant holders and controlling implant kinematics during the simulation. For component design, a 3D computer-aided design software was used. After the manufacturing of all components had been completed, the redesigned system was put into operation. In a final wear test, functionality and conformance with the ISO standard were tested for the modified simulator. After implementation of design modifications, it is possible to run wear tests with a medially biased load distribution according to ISO 14243.
Instrumentation for Testing Soft Tissue Undergoing Large Deformation: Ex Vivo and In Vivo Studies
Authors: Hu Tie , Lau Alan C. W. , Desai Jaydev P.
Published: November 2008

Biomechanical property of soft tissue derived from experimental measurements is critical to develop a reality-based soft-tissue model for minimally invasive surgical training and simulation. In our research, we have focused on developing a biomechanical model of the liver with the ultimate goal of using this model for local tool-tissue interaction tasks and providing feedback to the surgeon through a haptic (sense of touch) display. In this paper, we present two devices that we have designed and built, namely, ex vivo and in vivo testing devices. We used them to measure the experimental force and displacement data of pig liver tissue. The device for ex vivo experiments uses a PC-based control system to control the motion of the probe and acquire the experimental force and displacement data. The force resolution for ex vivo testing was 0.002N (as per the resolution information provided by the manufacturer) and the probe velocity ranged from 0.1mm∕s to 25.4mm∕s. The device was designed so that it could be easily used for both small probe (tissue sample larger than the indenting probe surface area) testing as well as large probe (tissue sample smaller than the indenting probe surface area) testing. The device for in vivo experiments used a microcontroller-based instrumentation to control the motion and acquire and store the data on a multimedia memory disk. This device is designed for the purpose of acquiring experimental force and displacement data in vivo. The primary challenge in the design of the device for in vivo experiments was the limited workspace for device operation. The force resolution for in vivo testing was 0.015N and the displacement resolution was 0.02mm. The sampling frequency for data acquisition for in vivo testing was 50Hz.
An Engineering Approach for Quantitative Analysis of the Lengthwise Strokes in Massage Therapies
Authors: Zeng Hansong , Butterfield Timothy A. , Agarwal Sudha , Haq Furqan , Best Thomas M. , Zhao Yi
Published: November 2008

Massage therapies are widely used for improving and restoring the function of human tissues. It is generally accepted that such therapies promote human health and well-being by several possible mechanisms, including increase in blood flow and parasympathetic activity, release of relaxation hormones, and inhibition of muscle tension, neuromuscular excitability, and stress hormones. Nonetheless, most of the purported beneficial/adverse effects of massage are based on anecdotal experiences, providing little insight on its effectiveness or the mechanisms underlying its usefulness. Furthermore, most studies to date have not quantitatively demonstrated the efficacy of massage on human health. This might be due to the lack of appropriate tools necessary for the application of quantitatively controlled loading and for the evaluation of the subsequent responses. To address this issue, we developed a device that applies compression in lengthwise strokes to the soft tissues of the New Zealand white rabbit, thereby mimicking the rubbing and effleurage techniques of massage. This device permits control of the magnitude and frequency of mechanical load applied to the rabbit’s hind limb for various durations. The measurement of tissue compliance and the viscoelastic properties as a function of loading parameters was also demonstrated. Findings of this study suggest that this device offers a quantitative analysis of the applied loads on the tissue to determine an optimal range of loading conditions required for the safe and effective use of massage therapies.
A Portable and Automated Postural Perturbation System for Balance
Assessment, Training, and Neuromuscular System Identification
Authors: Vette Albert H. , Sanin Egor , Bulsen Abdulkadir , Morris Alan , Masani Kei , Popovic Milos R.
Published: November 2008

To date, a postural perturbation system capable of generating position-, velocity-, and force-controlled perturbations while being portable and suitable for use during various postural scenarios does not exist. Therefore, the purpose of the present study was to design, develop, and test a portable and automated postural perturbation system (PAPPS) that can be used to measure and train postural reactions during sitting, standing, and treadmill walking. The core component of the PAPPS was a linear actuator that provides horizontal perturbations. The actuator could generate arbitrary displacement, velocity, or force perturbations as a function of time. In addition, the PAPPS was able to measure the actuator’s displacement, velocity, and load, which could be used to study postural perturbation responses. The height at which the PAPPS was delivering the perturbations could be easily adjusted to allow for different subject/patient anthropometrics and a wide range of postural scenarios such as sitting, standing, and treadmill walking. The PAPPS generated a peak displacement of 0.6m, a peak velocity of 0.5m∕s, and a peak force of 600N, which is more than sufficient to elicit high intensity postural perturbations. Multiple and nested safety circuits have been implemented into the PAPPS to ensure the safety of the subjects/patients during experiments and/or training. To evaluate the accuracy and repeatability of the PAPPS during position-, velocity-, and force-controlled perturbations, experiments were conducted using sinusoidal, impulse, and ramp profiles as a function of time. Highly sensitive displacement and force sensors that were external to the PAPPS were used to determine the accuracy and repeatability of the proposed device. In addition, a case study was performed to demonstrate the performance of the PAPPS during pseudorandom sinusoidal perturbations that were applied to a healthy individual during sitting. The accuracy and repeatability tests suggest that the PAPPS can generate reliable and high-precision displacement, velocity, and force perturbations. Potential applications of this system include, but are not limited to (1) studies of postural response to various perturbation types and profiles in diverse subject populations during sitting, standing, and treadmill walking, and (2) training of postural balance in diverse patient populations during sitting, standing, and treadmill walking.
Designing Fuzzy Controller in Compressive Chillers and Study of the Performance of Air Conditioning System With Fuzzy Versus Digital Controllers
Authors: Yousefi Hassan , Handroos Heikki , Dovali Reza , Soleymani Azita
Published: November 2008

Subject of this paper is designing of fuzzy controller in compressive chillers and study of air-conditioning system performance with fuzzy controller versus common digital controller. Measured criteria in system performance include reaction speed, resistance against turbulence and parameters change in system, lowering the energy consumption and monotonicity of circuit compressor’s functioning time during a period of system functioning. Results make the fact clear that using fuzzy controllers will improve all performance evaluation criteria compared with common controllers.
Condition Monitoring of Lift Gear Boxes by Means of Sound Analysis
Authors: Ozkirim Mustafa , Imrak C. Erdem , Uzunoglu Hakan
Published: November 2008

The method of Condition Monitoring (CM) or Condition Based Maintenance (CBM) of machinery is straightforward since it aims to identify the changes in the condition of a machine during operation that will indicate some potential failure. This is achieved by utilizing various techniques such as Thermography, Oil Analysis and Ultrasonics. For all maintenance engineers’ diagnosis of gear defects by using sound analysis may be an effective technique in that it provides economic and continuous fault monitoring. In the study, in order to detect the defects in worm gears driven by electric motors, the samples of the sound vibrations emitted from the gears with and without defects are recorded by means of a sound recorder. The comparison of these sound records proved that the acoustic condition monitoring system is able to detect the faulty gears of the elevator drive units.
Robustness, Fidelity and Prediction-Looseness of Models
Authors: Ben-Haim Yakov , Hemez Franc¸ois M.
Published: November 2008

Assessment of the credibility of a mathematical or numerical model of an engineering system must combine three components: (1) The fidelity of the model to test data. (2) The robustness, of model fidelity, to lack of understanding of the underlying processes. (3) The prediction looseness of the model. ‘Prediction looseness’ is the range of predictions of models which are equivalent in terms of fidelity. The main result of this paper is that high fidelity, high robustness, and small prediction looseness are mutually incompatible. A model with high fidelity to data and high robustness to imperfect understanding of the process, will have low predictive focus. Our analysis is based on info-gap models of uncertainty.
Molten Metal Flow Visualization Using Mutual Induction Tomography (MIT)
Authors: Soleimani Manuchehr , Lionheart William R. B. , Peyton A. J. , Ma X.
Published: November 2008

The paper presents further progress in using mutual inductance tomography (MIT) system for molten metal flow visualisation. The MIT image which is the electric conductivity map is the shape of the flow. For the image reconstruction we applied an inverse finite element technique that is able to reconstruct fully 3D MIT images for the purpose of molten steel flow. The experimental tests has been conducted and the results for simulation flow model as well experimental results presented.
A Simplified Model of the Base-Excited Coulomb Friction Oscillator With Contact Compliance and Inertia
Authors: Liang Jin-Wei
Published: November 2008

This work investigates a base-excited Coulomb oscillator with contact compliance and inertia. The full-order system is a two degree-of-freedom (DOF) problem. The study first shows that two existing approximate models, including the rigid-contact model (RCM) and the compliant-contact model (CCM) cannot closely capture the dynamical characteristics of the global pure-sliding responses of the full-order system (FOS). To complement for this, this study proposes a new approximate model denoted as the reduced-order system (ROS), which is especially suitable for studying the contact dynamics subjected to the global pure-sliding motion. Numerical results show that the ROS not only has the merit of simplicity can also reliably depict the global pure-sliding features of the FOS. Furthermore, relevant stick-slip phenomena associated with the ROS (the transformed problem) are revealed and illustrated in time-domain and phase-space trajectories.
Dynamic Characteristics Analysis of Flexible Mechanism Using Three Parameters Damping Model
Authors: Liu Hongzhao , Liu Baixi , Yuan Daning
Published: November 2008

In this paper, a practical structural damping model for the dynamic analysis of damping alloy is presented. The differential equations of the beam element with three parameters representing stiffness and damping characteristics are deduced through the three parameters constitution and the virtual work principle. By means of the Kineto-Elastodynamic theory, the established element dynamic equations are assembled into the system dynamic equations of flexible linkage mechanism. In order to solve the high order differential equations with time-varying coefficients, a closed form numerical algorithm is constructed. Lastly, an example of a four-bar elastic linkage mechanism is given to show the effectiveness of the proposed method in studying dynamic characteristics of structure containing damping alloy components.
Five Parameters Structural Damping Constitution and Its Application
Authors: Liu Baixi , Liu Hongzhao , Yuan Daning
Published: November 2008

In this paper, the five parameters model of viscoelastic theory is introduced as the constitutive equation for damping alloy. Based on the experiment data, the five parameters are fitted by using an optimization algorithm. The finite element dynamic equations are derived through the established five parameters constitution. For the convenience of the computation, the established dynamic equations containing convolution integration are changed into ordinary differential equations. By means of the Kineto-Elastodynamic theory, the system dynamic equation of elastic linkage mechanism is gained. In order to solve the high order differential equations, the state space method is employed. An example is given to show that the model proposed in this paper is more accurate and stable than the three parameters damping model.
Impulse-Momentum in Spacecraft Landing: Analysis and Experiment
Authors: Chong Chung-Ook , Dix Rollin
Published: November 2008

Impulse-momentum methods of analysis developed for rigid body impacts are applied in this paper to predict forces acting in a simplified spacecraft model during a touchdown impact. This paper presents both analytic and experimental effort for a complex, multi-body impacting system that include friction and deformable elements. Specifically, we analyze a vertically moving guided mass representing a landing spacecraft to which is attached a telescopic, energy-absorbing leg. The landing gear, which is used in our study, employs crushable material in the leg, strut, and foot plus surface friction to absorb the landing shock. The experimental setup consists of simplified landing system, and accelerometers for the dynamic measurement. Acceleration data collected via data acquisition system is converted to the crushing, normal and tangential velocities. The results showed good agreement between the analysis and experiment for the first phase of motion. The derivation of limiting condition equations for all possible alternatives for the second phase is incomplete. We conclude that the challenges of deriving and testing for all motion phase ending events make the impulse-momentum method inferior to straight-forward dynamic simulation as a design tool.
Structural Optimization of Dental Restorations Using the Principle of Adaptive Growth
Authors: Couegnat Guillaume , Fok Siu L. , Cooper Jonathan E. , Qualtrough Alison J. E.
Published: November 2008

Fracture of restored teeth is a problem in restorative dentistry since it has been estimated that 92 percent of fractured teeth have been previously restored. In a restored tooth, the stresses that occur at the tooth-restoration interface during loading could become large enough to fracture the tooth and/or restoration. The tooth preparation process for a dental restoration is therefore a classical optimization problem: tooth reduction must be minimized to preserve tooth tissue whilst stress levels must be kept low to avoid fracture of the restored tooth. The objective of the present study was to propose alternative optimized designs for a second upper premolar cavity preparation by means of structural shape optimization based on the finite element method and biological adaptive growth. Restored tooth models using the optimized cavity shapes exhibited significant reduction of stresses along the tooth-restoration interface. In the best case, the maximum stress value was reduced by more than 50 percent.