bluuebunny/crossref_metadata_2025 huggingface dataset:
An Analytical Model for Dynamic Wear
Authors: Lin Ji-Yi , Cheng H. S.
Published: October 2009

A wear model which permits the wear rate to be dependent on time is introduced to study the dynamic wear behavior observed in practice. In this model, it is postulated that the wear rate is proportional to a forcing term, I, which is contributed by the stress field induced by the frictional force at the asperity contacts; and inversely proportional to a wear resisting term, S, which is related to the material antiwear strength near the surface. One of the important characteristics of the dynamic wear model is that both I and S are now time dependent or wear dependent because when wear progresses the material strength at various layers would change and the stress field would also change as a result of the change of surface topography. Using this dynamic wear model, it is shown that the commonly observed running-in, steady-state, or accelerated wear phenomena can be explained.
Modelling Friction Under Complex Motion Conditions
Authors: Stolarski T. A.
Published: October 2009

An analytical model of friction under combined linear sliding and spin of the contact area is presented. It is shown that the model, although based on simplifying assumptions, predicts reasonably well the characteristic features of the friction process.
Averaged Reynolds Equation Extended to Gas Lubrication Possessing Surface Roughness in the Slip Flow Regime: Approximate Method and Confirmation Experiments
Authors: Mitsuya Y. , Ohkubo T. , Ota H.
Published: October 2009

The average film thickness theory is extended to gas lubrication possessing surface roughness in the slip flow regime. A simplified averaged Reynolds equation is derived and its applicability is confirmed through comparing with experiments. This averaging equation makes use of the mixed average film thickness defined as Havem = αHm + (1 − α)Hmˆ, where m = 1, 2 and 3; α indicates the mixing ratio; and H¯ and Hˆ denote the arithmetically and harmonically averaged film thicknesses. The experiments were performed using computer flying heads having precisely photolithography-fabricated longitudinal, transverse or checkered pattern roughnesses under submicron spacing conditions. From the excellent agreement obtained between the calculated and experimental results, it can be concluded that the assumption that velocity slippage occurs along the surface even if roughnes is present is justified, and that the approximate method is applicable for determining the surface roughness effects in the slip flow regime.
Thermohydrodynamic Performance of Thrust Bearings With Circular Tilted Pads Under the Presence of Air Gas Bubbles and Centrifugal Forces
Authors: Abdel-Latif L. A. , Bakr E. M. , Ghobrial M. I.
Published: October 2009

This paper deals with the analysis of thrust bearings with tilted circular pads running under thermohydrodynamic conditions. During operation, a considerable quantity of air/gas bubbles is dispersed inside the lubricating oil and build a compressible medium. The important lubricant properties, namely viscosity and density are altered substantially due to bubble presence as well as temperature rise. The influence of the centrifugal forces become significant as the speed and load become higher. Such type of bearings has been herein investigated taking into account both influencing phenomena. The geometric and loading parameters are varied to show the combined effect on the bearing characteristic values. The governing equations of the THD theory are solved numerically using the finite difference method. The surface tension of bubbles and the change of bubble content with temperature and pressure are included in the governing equations as are the centrifugal forces.
Calculation of Rotordynamic Coefficients and Leakage for Annular Gas Seals by Means of Finite Difference Techniques
Authors: Nordmann R. , Dietzen F. J. , Weiser H. P.
Published: October 2009

The compressible flow in a seal can be described by the Navier-Stokes equations in connection with a turbulence model (k–ε model) and an energy equation. By introducing a perturbation analysis in these differential equations we obtain zeroth order equations for the centered position and first order equations for small motions of the shaft about the centered position. These equations are solved by a finite difference technique. The zeroth order equations describe the leakage flow. Integrating the pressure solution of the first order equations yields the fluid forces and the rotordynamic coefficients, respectively.
Micropitting in Rolling and Sliding Contact Under Mixed Lubrication
Authors: Zhou R. S. , Cheng H. S. , Mura T.
Published: October 2009

Based on morphological tests in rolling and sliding contact, the effect of surface film, the subsurface heavily dislocated layer, crack initiation, crack propagation, and micropitting have been investigated by using a two-disk rig. A micro-macro contact model is presented for surface pitting in rolling and sliding contacts. In this model the pressures related to asperity interaction and the subsurface stress map along whole contact area have been analyzed by superimposing the asperity contacting loads on the Hertzian load for a given specimen surface. Compared to the experimental results, this model is capable of predicting the onset of micropits for given mechanical and lubrication conditions. Cracking is assumed to occur when the accumulated strain energy of the dislocation reaches a critical value. A three-dimensional crack propagating model has also been used for pitting life prediction in rolling and sliding contact.
Application of Porous Materials to Annular Plain Seals: Part 1—Static Characteristics
Authors: Kaneko S.
Published: October 2009

Porous materials are applied to the annular plain seals employed in pumps by insertion into the inlet part of the seal. The static characteristics of the seals with the porous materials are studied in the laminar-flow regime. The Reynolds equation for the fluid film in the seal clearance is modified to include a so-called filter term, and the pressure equation for the porous matrix is obtained from Darcy’s law and the continuity equation. These equations are applied to the system and are numerically solved with the pressure drop mainly due to the axial acceleration of liquid at the inlet end of the seal being taken into account. Results show that the annular plain seals with the porous materials have larger fluid film force component along the line of centers and smaller one perpendicular to the former than the ordinary solid seals.
On Thermally Induced Seizure in Journal Bearings
Authors: Khonsari M. M. , Kim H. J.
Published: October 2009

Rapid thermal expansion of the shaft during the start-up period can lead to a complete loss of bearing clearance and seizure in the absence of lubrication. The equations governing the transient thermoelastic behavior of the shaft are solved numerically. Results are provided for the time of seizure as a function of displacement. It is shown that the presence of shaft misalignment can significantly influence the time of seizure.
The Unlubricated Sliding Wear Behavior of a Wrought Cobalt-Chromium Alloy Against Monolithic Ceramic Counterfaces
Authors: Cooper C. V. , Rollend C. L. , Krouse D. H.
Published: October 2009

The unlubricated sliding wear and friction behavior of a wrought cobalt-chromium alloy against sintered Al2O3, ZrO2-toughened Al2O3, MgO-partially-stabilized ZrO2, and hot-pressed Si3N4 ceramic counterfaces has been investigated. Both untreated (baseline) and surface-borided conditions of alloy 6B disks were investigated. The dominant wear and/or material degradation mechanism for surface-borided alloy 6B was a combination of abrasion and plastic deformation; in addition, adhesive transfer of the cobalt alloy to monolithic Al2O3 counterfaces was a significant wear mechanism for the as-solution-treated alloy 6B disk. For the partially stabilized ZrO2 counterface, the degradation mechanism involved thermal and/or mechanical fatigue processes, resulting in the formation of microcracks in the 6B disks transverse to the sliding direction. This microcracking has been ascribed to the low thermal conductivity of the partially stabilized ZrO2 and the activation of a martensitic, fcc-to-hcp transition with each passing of the ZrO2 ball. For borided alloy 6B against hot-pressed Si3N4, a transition from negligible to severe wear was noted with increasing sliding speeds.
The Mechanism of Lubrication in Low Speed Rolling Contacts
Authors: Holmberg K.
Published: October 2009

The mechanism of lubrication in low speed rolling and sliding contacts was investigated. It was found to be a combination of the following three effects: the chemical formation of boundary lubrication films on the surfaces, the creation of hydrostatic pressure in the lubricant trapped by the surface topography, and the squeeze effect of lubricant in grooves formed by the surface topography. The three different effects were recognized by friction measurements in a four-disk machine. The results indicate that the way in which the surface topography forms dents and grooves influences the flow behavior of the lubricant in the contact. Thus both the surface topography and the viscosity of the lubricant are important parameters affecting friction and wear even in low speed rolling contacts where no hydrodynamic wedge effect is expected to occur.
Structure of Monomeric Yeast and Mammalian Sec61 Complexes Interacting with the Translating Ribosome
Authors: Becker Thomas , Bhushan Shashi , Jarasch Alexander , Armache Jean-Paul , Funes Soledad , Jossinet Fabrice , Gumbart James , Mielke Thorsten , Berninghausen Otto , Schulten Klaus , Westhof Eric , Gilmore Reid , Mandon Elisabet C. , Beckmann Roland
Published: October 2009

Nascent Chains Revealed

Detailed analysis of protein translation and translocation across membranes requires the identification and structural analysis of intermediates involved in these processes (see the Perspective by

Kampmann and Blobel

).

Seidelt
et al.

(p.
1412
, published online 29 October) report the visualization by cryo-electron microscopy of a nascent polypeptide chain in the tunnel of the ribosome at 5.8 angstroms. This resolution allows analysis of the conformation and distinct contacts of the nascent chain within the ribosomal tunnel, which suggests a mechanism by which translational stalling is induced by this peptide. Protein translocation across cellular membranes involves the Sec61 protein, a component of a protein-conducting channel. Whether Sec61 acts as a monomer or as an oligomer during protein translocation has been unclear.

Becker
et al.

(p.
1369
, published online 29 October) describe active yeast and mammalian ribosome-Sec61 structures that show the Sec61 complex interacting with the ribosome and a nascent secretory protein signal sequence. The analysis unambiguously reveals that the active protein-conducting channel is a single Sec61 copy with its central pore serving as conduit for the nascent polypeptide.
Who should consent for research in adult intensive care? Preferences of patients and their relatives: a pilot study
Authors: Chenaud C , Merlani P , Verdon M , Ricou B
Published: October 2009

Introduction:

Research in intensive care is necessary for the continuing advancement of patient care. In research, informed consent is considered essential for patient protection. In intensive care, the modalities of informed consent are currently being debated by both lawyers and the medical community. The preferences of patients and their relatives regarding informed consent for research in intensive care have never been assessed. The aim of this study was to investigate these preferences.

Methods:

A pilot study conducted via a questionnaire mailed to patients and relatives who had experienced intensive care.

Results:

52/400 patient–relative pairs completed the questionnaire fully. If the patient was imagined to be conscious, 75% of patients and 77% of relatives believed the patient should be the person who should consent. If the patient was imagined to be unconscious, 72% of patients and 67% of relatives thought that a relative should be asked to consent. The majority of responders thought that at least two persons should consent. Their answers were concordant in 61–80% of cases, depending on the question. Patients (25%) and relatives (30%) did not feel free in their decision to participate in a study. The majority of patients and relatives wanted to consent by writing, indifferently with or without a witness.

Conclusion:

Patients are willing to decide on their own participation in a study. If they lose their capacity to decide for themselves, in the great majority of cases, they would agree to delegate the decision to a relative.
The acceptability among French lay persons of ending the lives of damaged newborns
Authors: Teisseyre N , dos Reis I Duarte , Sorum P C , Mullet E
Published: October 2009

Background:

Lay persons’ judgements of the acceptability of the not uncommon practice of ending the life of a damaged neonate have not been studied.

Methods:

A convenience sample of 1635 lay people in France rated how acceptable it would be for a physician to end a neonate’s life—by withholding care, withdrawing care, or active euthanasia—in 54 scenarios in which the neonate was diagnosed either with perinatal asphyxia or a genetic abnormality. The scenarios were all combinations of four factors: three levels of maturity or immaturity, three levels of severity of the health problem, three levels of parents’ preference concerning prolonging care and two levels of decision-making (with or without consulting the other caregivers).

Analyses:

Analyses of variance of the participants’ responses were performed to determine the importance of each factor; the interactions among factors, with methods of ending life and with other patient characteristics; and the differences between asphyxia and genetic abnormality. A cluster analysis was performed to look for groups with different patterns of responses.

Results:

Lay people assigned most importance to the parents’ request and to the severity of the problem. Except for a small group (12%) always opposed to ending life, they used a simple additive-type rule in integrating the information.

Implications:

Most of this sample of French lay people are not categorically for or against ending the life of a damaged neonate, but judge its degree of acceptability by adding up those factors that seem most salient to them.
NICE guidelines, clinical practice and antisocial personality disorder: the ethical implications of ontological uncertainty
Authors: Pickersgill M D
Published: October 2009

The British National Institute for Health and Clinical Excellence (NICE) has recently (28 January 2009) released new guidelines for the diagnosis, treatment and prevention of the psychiatric category antisocial personality disorder (ASPD). Evident in these recommendations is a broader ambiguity regarding the ontology of ASPD. Although, perhaps, a mundane feature of much of medicine, in this case, ontological uncertainty has significant ethical implications as a product of the profound consequences for an individual categorised with this disorder. This paper argues that in refraining from emphasising uncertainty, NICE risks reifying a controversial category. This is particularly problematical given that the guidelines recommend the identification of individuals “at risk” of raising antisocial children. Although this paper does not argue that NICE is “wrong” in any of its recommendations, more emphasis should have been placed on discussions of the ethical implications of diagnosis and treatment, especially given the multiple uncertainties associated with ASPD. It is proposed that these important issues be examined in more detail in revisions of existing NICE recommendations, and be included in upcoming guidance. This paper thus raises key questions regarding the place and role of ethics within the current and future remit of NICE.
On the ethics of oestrogen treatment for tall girls: an update
Authors: Louhiala P
Published: October 2009

New empirical evidence on the long-term effects of oestrogen treatment for tall adolescent girls has shown that the intended psychosocial benefit of the treatment may not have been realised. This paper describes recent trends in the prevalence of the treatment and the results of a large Australian cohort study evaluating girls assessed between 1959 and 1993 for excessive growth. The paper concludes that oestrogen treatment to prevent extreme tallness should belong to the past, not to the future.
Harmonisation of ethics committees' practice in 10 European countries: Figure 1
Authors: Hernandez R , Cooney M , Dualé C , Gálvez M , Gaynor S , Kardos G , Kubiak C , Mihaylov S , Pleiner J , Ruberto G , Sanz N , Skoog M , Souri P , Stiller C O , Strenge-Hesse A , Vas A , Winter D , Carné X
Published: October 2009

Background:

The Directive 2001/20/EC was an important first step towards consistency in the requirements and processes for clinical trials across Europe. However, by applying the same rules to all types of drug trials and transposing the Directive’s principles into pre-existing national legislations, the Directive somewhat failed to meet its facilitation and harmonisation targets. In the field of ethics, the Directive 2001/20/EC conditioned the way of understanding and transposing the “single opinion” process in each country. This led to a situation in which two models of research ethics committees organisation systems exist, being the model in which the “single opinion” is considered to be the decision made by a single ethics committee more effective and simpler in terms of administrative and logistic workload.

Method:

A survey was conducted in 10 European countries. Members of the European Clinical Research Infrastructures Network working party number 1, with expertise in the field of ethics, responded.

Results:

There is a major heterogeneity in the composition of ethics committees among the surveyed countries based on the number of members, proportion of experts versus lay members and expertise of the scientific members. A harmonised education of the ethics committees’ membership based in common curricula is recommended by the majority of countries.

Conclusions:

Despite the efforts for harmonisation of the European Clinical Trial Directive, from an ethical point of view, there remains a plurality of ethics committees' systems in Europe. It is important to comprehend the individual national systems to understand the problems they are facing.
Fallacies in the arguments for new technology: the case of proton therapy
Authors: Hofmann B
Published: October 2009

In a seminal article in theJournal of Medical Ethics, Søren Holm and Tuja Takala analysed two protechnology arguments in bioethics: thehopeful principleand theautomatic escalator. They showed how these arguments relate to problematic arguments such as theprecautionary principleand the empiricalslippery slope argument, and argued that they should be used with great caution. The present article investigates the recent debate on proton beam therapy, where the hopeful principle and the automatic escalator are identified. However, the debate reveals a series of other arguments that deserve similar caution. An analysis of these arguments indicates that the roots of their fallacies are to be found in the ignorance of the uncertainties about risks and benefits and an overly optimistic attitude towards technology and progress. The point is not to argue against proton therapy, but rather to point out that flawed arguments for new technologies, such as proton therapy, can actually hamper their implementation instead of promoting it. Patients deserve the best technology available, not only on the basis of the best available evidence, but also on the basis of the best arguments.
A NOVEL APPROACH TO VERIFY GRAPH SCHEMA-BASED SOFTWARE SYSTEMS
Authors: RAFE VAHID , RAHMANI ADEL T.
Published: October 2009

Graph Grammars have recently become more and more popular as a general formal modeling language. Behavioral modeling of dynamic systems and model to model transformations are a few well-known examples in which graphs have proven their usefulness in software engineering. A special type of graph transformation systems is layered graphs. Layered graphs are a suitable formalism for modeling hierarchical systems. However, most of the research so far concentrated on graph transformation systems as a modeling means, without considering the need for suitable analysis tools.

In this paper we concentrate on how to analyze these models. We will describe our approach to show how one can verify the designed graph transformation systems. To verify graph transformation systems we use a novel approach: using Bogor model checker to verify graph transformation systems. The AGG-like graph transformation systems are translated to BIR — the input language of Bogor — and Bogor verifies that model against some properties defined by combining LTL and special purpose graph rules. Supporting schema-based and layered graphs characterize our approach among existing solutions for verification of graph transformation systems.
AN EFFICIENT LOTOS-BASED FRAMEWORK FOR DESCRIBING AND SOLVING (TEMPORAL) CSPs
Authors: SADAOUI SAMIRA , MOUHOUB MALEK , CHEN BO
Published: October 2009

Simulation of complex Lotos specifications is not always efficient due to the space explosion problem of their corresponding transition systems. To overcome this difficulty in practice, we present in this paper a novel approach which integrates constraint propagation techniques into the Lotos specifications. These solving techniques are used to reduce the size of the search space before and during the search for a solution to a given combinatorial problem under constraints. In order to do that, we first tackle the challenging task of describing combinatorial problems in Lotos using the Constraint Satisfaction Problem (CSP) framework. In this regard, we provide two generic Lotos templates for describing CSPs and temporal CSPs (CSPs involving temporal constraints). To evaluate the time performance of the framework we propose, we have conducted several experimental tests on instances of the N-Queens, the machine scheduling and randomly generated CSPs. The results of these experiments are promising and demonstrate the efficiency of Lotos simulation when CSP techniques are integrated.
SOFTWARE DEFECT PREDICTION USING INTERTRANSACTION ASSOCIATION RULE MINING
Authors: CHANG CHING-PAO , CHU CHIH-PING
Published: October 2009

Reducing the variance between expectation and execution of software processes is an essential activity for software development, in which the Causal Analysis is a conventional means of detecting problems in the software process. However, significant effort may be required to identify the problems of software development. Defect prevention prevents the problems from occurring, thus lowering the effort required in defect detection and correction. The prediction model is a conventional means of predicting the problems of subsequent process actions, where the prediction model can be built from the performed actions. This study proposes a novel approach that applies the Intertransaction Association Rule Mining techniques to the records of performed actions in order to discover the patterns that are likely to cause high severity defects. The discovered patterns can then be applied to predict the subsequent actions that may result in high severity defects.
ONTOLOGY-BASED INFORMATION EXTRACTION FROM PDF DOCUMENTS WITH XONTO
Authors: ORO ERMELINDA , RUFFOLO MASSIMO , SACCÀ DOMENICO
Published: October 2009

Information extraction is of paramount importance in several real world applications in the areas of business, competitive and military intelligence because it enables to acquire information contained in unstructured documents and store them in structured forms. Unstructured documents have different internal encodings, one of the most diffused encoding is the visualization-oriented Adobe portable document format (PDF). Although several sophisticated and indeed complex approaches were proposed, they are still limited in many aspects. In particular, existing information extraction systems cannot be applied to PDF documents because of their completely unstructured nature that pose many issues in defining IE approaches. In this paper the novel ontology-based system named XONTO, that allows the semantic extraction of information from PDF documents, is presented. The XONTO system is founded on the idea of self-describing ontologies in which objects and classes can be equipped by a set of rules named descriptors. These rules represent patterns that allow to automatically recognize and extract ontology objects contained in PDF documents also when information is arranged in tabular form. This way a self-describing ontology expresses the semantic of the information to extract and the rules that, in turn, populate itself. In the paper XONTO system behaviors and structure are sketched by means of a running example.
ENTANGLEMENT, PURITY AND VIOLATION OF BELL INEQUALITY
Authors: DENG DONG-LING , CHEN JING-LING
Published: October 2009

We use the Clauser–Horne–Shimony-Holt (CHSH) inequality to investigate the relationship among entanglement, purity and violation of the Bell inequality. On the one hand, we show numerically that all two-dimensional (qubit) states, whose entanglement of formation (EOF) is larger than [Formula: see text], violate the CHSH inequality. On the other hand, any state with purity smaller than 0.5562 may not violate it.
PAIRWISE ENTANGLEMENT DYNAMICS OF A MULTIPARTITE SYSTEM IN THE TAVIS–CUMMINGS MODEL
Authors: HAN FENG , XIA YUN-JIE
Published: October 2009

The pairwise entanglement dynamics in a multipartite system consisting of three two-level atoms A, B, C and a single-mode cavity field a is studied via negativity. Three atoms are arranged in such a way that atoms BC are embedded in and locally interact with the cavity while atom A is located in a spatially separate place outside of the cavity. Initially, atom-pair AB is prepared in a Bell-like state while atom C in a superposition of ground and excited state, |gC〉 and |eC〉. It shall be shown that all the pairwise negativities of the total system including atoms and cavity undergo qualitatively different evolutions. The so-called entanglement sudden death is observed for atom-pair AB under certain conditions and the entanglement transfer among all the possible degrees of freedom of the whole system is also discussed.
EFFECTS OF ANISOTROPY ON DYNAMICS OF PAIRWISE ENTANGLEMENT IN THE FOUR-QUBIT HEISENBERG XXZ MODEL
Authors: GUO JIN-LIANG , SONG HE-SHAN
Published: October 2009

We investigate the effects of anisotropy on the dynamic evolution of pairwise entanglement in the four-qubit Heisenberg XXZ model. The entanglement between the nearest-neighbor and the next nearest-neighbor qubits are calculated by making use of concurrence. Our results show that the sudden death effect can be weakened when introducing the anisotropy Δ. In addition, we also find that the anisotropy Δ can protect the entanglement between the nearest-neighbor qubits from being completely destroyed by the intrinsic decoherence, but it cannot do this for the entanglement between the next nearest-neighbor qubits.
ENTANGLEMENT-ASSISTED QUANTUM ERROR-CORRECTING CODES CONSTRUCTED FROM IRREGULAR REPEAT ACCUMULATE CODES
Authors: WANG YUNJIANG , BAI BAOMING , ZHAO WENBO , WANG XINMEI
Published: October 2009

In some contexts, it would make sense to look for codes that can use the maximal amount of shared ebits between sender and receiver, in order to boost qubit channel yield. Also, the codes are also expected to have feat net rates, when there are not enough ebits shared between the sender and receiver. In this paper, entanglement-assisted irregular quantum error-correcting codes achieving this goal are constructed from quaternary classical irregular repeat accumulate codes. Because of their sparse tanner graphs, the constructed codes have relatively low polynomial time-encoding complexity, and can be efficiently decoded by using sum–product algorithm. Moreover, the simulation results show that they outperform their existing quantum regular counterparts which are based on binary classical regular codes.
PROPERTIES OF A NONLINEAR BLASCHKE PRODUCT DECOMPOSITION ALGORITHM
Authors: VAN VLIET DANIEL
Published: October 2009

Motivated by developments in nonlinear time–space–frequency analysis such as Refs. 8 and 14, we investigate the properties of Blaschke products. Inner products are constructed under which certain sets of Blaschke products, each have a single zero location, form orthonormal bases for H2(D). Using these sets of Blaschke products as approximants, a greedy algorithm decomposition is implemented. Properties are observed which may help to develop a faster search type algorithm.
IL-22 is involved in liver regeneration after hepatectomy
Authors: Ren Xiaodan , Hu Bin , Colletti Lisa M.
Published: October 2009

Hepatocyte proliferation following partial hepatectomy is an important component of liver regeneration, and recent in vitro studies have shown that IL-22 is involved in cellular proliferation in a variety of cell types, including hepatocytes. IL-22 functions through IL-10Rβ and IL-22Rα. The goal of this study was to investigate the potential role of IL-22 in liver regeneration after 70% hepatectomy. Following 70% hepatectomy, done under general anesthesia in mice, serum IL-22 and hepatic IL-22Rα mRNA were significantly increased. Although administration of exogenous IL-22 prior to hepatectomy did not increase hepatocyte proliferation, administration of anti-IL-22 antibody before hepatectomy did significantly decrease hepatocyte proliferation. Furthermore, IL-22 treatment prior to 70% hepatectomy induced stat-3 activation; no significant changes were seen in ERK1/2 activation, stat-1 activation, or stat-5 activation. IL-22 pretreatment also significantly increased hepatic and serum IL-6 levels. In addition, animals treated with anti-IL-22 antibody also expressed less TGF-α. In conclusion, these data suggest that IL-22 is involved in liver regeneration and this may be due to interaction with IL-6 and TGF-α cascades.
A novel estrogen receptor GPER inhibits mitochondria permeability transition pore opening and protects the heart against ischemia-reperfusion injury
Authors: Bopassa Jean Chrisostome , Eghbali Mansoureh , Toro Ligia , Stefani Enrico
Published: October 2009

Several studies have recently demonstrated that G protein-coupled receptor 30 (GPER) can directly bind to estrogen and mediate its action. We investigated the role and the mechanism of estrogen-induced cardioprotection after ischemia-reperfusion using a specific GPER agonist G1. Isolated hearts from male mice were perfused using Langendorff technique with oxygenated (95% O2 and 5% CO2) Krebs Henseleit buffer (control), with G1 (1 μM), and G1 (1 μM) together with extracellular signal-regulated kinase (Erk) inhibitor PD-98059 (5μM). After 20 min of perfusion, hearts were subjected to 20 min global normothermic (37°C) ischemia followed by 40 min reperfusion. Cardiac function was measured, and myocardial necrosis was evaluated by triphenyltetrazolium chloride staining at the end of the reperfusion. Mitochondria were isolated after 10 min of reperfusion to assess the Ca2+ load required to induce mitochondria permeability transition pore (mPTP) opening. G1-treated hearts developed better functional recovery with higher rate pressure product (RPP, 6140 ± 264 vs. 2,640 ± 334 beats·mmHg−1·min−1, P < 0.05). The infarct size decreased significantly in G1-treated hearts (21 ± 2 vs. 46 ± 3%, P < 0.001), and the Ca2+ load required to induce mPTP opening increased (2.4 ± 0.06 vs. 1.6 ± 0.11 μM/mg mitochondrial protein, P < 0.05) compared with the controls. The protective effect of G1 was abolished in the presence of PD-98059 [RPP: 4,120 ± 46 beats·mmHg−1·min−1, infarct size: 53 ± 2%, and Ca2+ retention capacity: 1.4 ± 0.11 μM/mg mitochondrial protein ( P < 0.05)]. These results suggest that GPER activation provides a cardioprotective effect after ischemia-reperfusion by inhibiting the mPTP opening, and this effect is mediated by the Erk pathway.
Physiology of obesity and effects on lung function
Authors: Salome Cheryl M. , King Gregory G. , Berend Norbert
Published: October 2009

In obese people, the presence of adipose tissue around the rib cage and abdomen and in the visceral cavity loads the chest wall and reduces functional residual capacity (FRC). The reduction in FRC and in expiratory reserve volume is detectable, even at a modest increase in weight. However, obesity has little direct effect on airway caliber. Spirometric variables decrease in proportion to lung volumes, but are rarely below the normal range, even in the extremely obese, while reductions in expiratory flows and increases in airway resistance are largely normalized by adjusting for lung volumes. Nevertheless, the reduction in FRC has consequences for other aspects of lung function. A low FRC increases the risk of both expiratory flow limitation and airway closure. Marked reductions in expiratory reserve volume may lead to abnormalities in ventilation distribution, with closure of airways in the dependent zones of the lung and ventilation perfusion inequalities. Greater airway closure during tidal breathing is associated with lower arterial oxygen saturation in some subjects, even though lung CO-diffusing capacity is normal or increased in the obese. Bronchoconstriction has the potential to enhance the effects of obesity on airway closure and thus on ventilation distribution. Thus obesity has effects on lung function that can reduce respiratory well-being, even in the absence of specific respiratory disease, and may also exaggerate the effects of existing airway disease.
Obesity, airway hyperresponsiveness, and inflammation
Authors: Shore Stephanie A.
Published: October 2009

Epidemiological data indicate that obesity is a risk factor for asthma, but the mechanistic basis for this relationship is not established. Here we review data from human subjects and animal models investigating the relationship between obesity and airway hyperresponsiveness, a characteristic feature of asthma. We discuss obesity as a state of chronic systemic inflammation resulting from interactions between adipocytes and adipose tissue macrophages that are recruited to obese adipose tissue. Finally, we focus on the possibility that aspects of this inflammation, particularly obesity-related changes in TNF-α, leptin, and adiponectin, may contribute to airway hyperresponsiveness in obesity. Determining how obesity promotes asthma may uncover novel therapeutic strategies that are effective in the obese asthmatic subject.
Does obesity produce a distinct asthma phenotype?
Authors: Lugogo Njira L. , Kraft Monica , Dixon Anne E.
Published: October 2009

Obesity and asthma prevalence have been increasing over the past decade. Epidemiological evidence demonstrates that obesity results in an increased risk of developing incident asthma. Even modest levels of increased weight increase asthma risk. Recently published data suggest that obese asthma patients may represent a distinct phenotype of asthma. Obese asthma patients demonstrate increased asthma severity, as indicated by increased exacerbations and decreased asthma control; however, they do not appear to have increased airway cellular inflammation. It seems likely that obesity does not contribute to asthma through conventional Th type 2-mediated inflammatory pathways but, rather, through separate mechanisms that are specific to the obese state. This may explain the variable responses of obese asthma patients to conventional asthma therapies, specifically, relative corticosteroid resistance. Small studies suggest improvements in the disease with weight loss in obese asthma patients, and other interventions to target asthma in obese individuals need to be investigated. Several postulated mechanisms for the occurrence of this distinct phenotype have been postulated: 1) the presence of comorbidities, such as gastroesophageal reflux disease and sleep disordered breathing, 2) systemic inflammation associated with obesity (with elevated levels of circulating cytokines, such as IL-6 and TNF-α), 3) increased oxidative stress, and 4) hormones of obesity, such as adiponectin, leptin, and resistin. Although the mechanisms underlying obesity in asthma require further investigation, obesity plays a major role in the asthma epidemic and likely results in a distinct phenotype of the disease.
Change of Morphological and Functional Characteristics of Retinal Pigment Epithelium Cells during Cultivation of Retinal Pigment Epithelium-Choroid Perfusion Tissue Culture
Authors: Miura Yoko , Klettner Alexa , Noelle Bernhard , Hasselbach Heike , Roider Johann
Published: October 2009

Aims: To evaluate the changes of morphological and functional characteristics of the retinal pigment epithelium (RPE)-choroid perfusion culture during cultivation. Methods: PorcineRPE-choroid tissue was cultivated in a perfusion tissue culture system. After the indicated times, histology, immunolocalization of collagen IV and von Willebrand factor, RPE cell viability with calcein-AM, TUNEL assay and occludin immunolocalization of RPE cells were examined. The tissue was treated with selective RPE treatment laser after different time periods and the wound healing response was characterized. Vascular endothelial growth factor secretion was measured by enzyme-linked immunosorbent assay. Results: On day 8, prominent morphological degenerative changes of RPE cells were observed in histology. According to the immunohistochemistry for collagen IV, the Bruch’s membrane did not display any obvious decomposition until day 8. Von Willebrand factor staining decreased during cultivation, especially at the choriocapillaris. Calcein-AM staining and TUNEL assay displayed the increase of apoptotic changes in only a minority of the cells on day 4, but in many cells on day 8. Occludin delocalization was observed on day 8. Selective RPE treatment laser-produced wounds were completely closed by monolayer RPE when wounded on fresh and 3-day-old cultures, but not when wounded on 6-day-old cultures. Vascular endothelial growth factor secretion was stable between days 2 and 5, but increased after that. Conclusion: Under the stated culture perfusion conditions, porcine RPE-choroid tissue was suitable for experimentation up to 5 days of maintenance.
Utility of the Follicular Lymphoma International Prognostic Index and the International Prognostic Index in Assessing Prognosis and Predicting First-Line Treatment Efficacy in Follicular Lymphoma Patients
Authors: Formica V. , Norman A.R. , Cunningham D. , Wotherspoon A. , Oates J. , Chong G.
Published: October 2009

Background: The Follicular Lymphoma International Prognostic Index (FLIPI) allows physicians to stratify patients into groups with distinct prognoses, however its ability to predict the treatment efficacy has not been fully investigated. The aim of this study was to validate on this respect the FLIPI system in an independent cohort and compare it with the International Prognostic Index (IPI) used for aggressive lymphomas. Methods: Records from patients referred to our unit with a diagnosis of follicular lymphoma (FL) were retrospectively reviewed. Data required for FLIPI and IPI scores were collected along with data regarding first-line chemotherapy and time to treatment failure (TTF) and overall survival (OS). Results: Of 162 patients screened, 130 were assessable for both (FLIPI and IPI) scores. OS for low-risk (LR) patients identified either with IPI or FLIPI was significantly longer compared to intermediate-risk (IR) and high-risk (HR) groups, with FLIPI allowing a more even patient distribution among the risk groups. For patients receiving first-line chemotherapy within 6 months of diagnosis, a low FLIPI score was associated with a longer TTF (3-year TTF rates: 68.0, 33.7 and 31.0% for FLIPI-defined LR, IR and HR patients, respectively, p = 0.026). Conclusion: Our data support the prognostic value of both IPI and FLIPI, with FLIPI demonstrating a more convenient patient distribution among risk classes. A low FLIPI score was also associated with a longer TTF. This might partially contribute to a more favourable prognosis.
Clinical Features and Survival Outcomes in Patients with Multiple Myeloma: Analysis of Web-Based Data from the Korean Myeloma Registry
Authors: Kim Seok Jin , Kim Kihyun , Kim Byung Soo , Jo Deog-Yeon , Kang Hye Jin , Kim Jin Seok , Mun Yeung-Chul , Kim Chul Soo , Sohn Sang Kyun , Eom Hyeon-Seok , Kwak Jae-Yong , Shim Hyeok , Yoon Hwi-Joong , Jin Jong-Youl , Min Chang-Ki , Shin Hyunchoon , Won Jong-Ho , Lee Je-Jung , Kwon Jung Hye , Joo Young-Don , Do Young Rok , Kim Sung-Hyun , Oh Sukjoong , Suh Cheolwon , Lee Junglim , Yoon Sung-Soo , Kim Min Kyoung , Bang Soo-Mee , Ryoo Hun-Mo , Kim Bong-Seog , Kim Hawk , Kim Hyo Jung , Kim Yang Soo , Park Chong Won , Lee Gyeong-Won , Shin Ho Jin , Park Seong Kyu , Park Joon Seong , Kim Ho Young , Lee Dong Soon , Lee Jae Hoon
Published: October 2009

Aim: The Korean Multiple Myeloma Working Party performed a nationwide registration of multiple myeloma patients via a web-based data bank system. Methods: We retrospectively analyzed registered data from 3,209 patients since 1999. Results: The median overall survival (OS) was 50.13 months (95% confidence interval: 46.20–54.06 months). Patients ≤40 years demonstrated a longer OS than patients >65 years of age (median OS 71.13 vs. 36.73 months, p < 0.001). Patients who received novel agents at any time during their treatments showed a longer OS than patients who did not (median OS 42.23 vs. 55.50 months, p < 0.001). Response to treatment was associated with OS, with tandem autologous stem cell transplantation (SCT) producing longer OS than single autologous SCT. Conclusions: We demonstrated associations between survival outcomes and treatment modalities as well as baseline disease characteristics in a registry of multiple myeloma patients using a web-based data analysis.
Successful Treatment of Hepatic Encephalopathy in a Patient with Acute Lymphoblastic Leukemia
Authors: Dada Reyad , Wilop Stefan , Jost Edgar , Galm Oliver , Gassler Nikolaus , Osieka Rainhardt
Published: October 2009

Infiltration of the liver with consecutive severe dysfunction is rarely seen in adult acute lymphoblastic leukemia (ALL). We describe a case of a 32-year-old woman with severe icterus, thrombocytopenia, neutropenia and hepatosplenomegaly. ALL was diagnosed. One day after admission, she developed hepatic encephalopathy with ammonia concentrations in plasma >100 μmol/l. Hepatic infiltration was presumed and chemotherapy was initiated immediately which led to resolution of hepatic encephalopathy and complete hematological remission. Clinicians should be aware of unusual presentations of ALL and difficulties for the application of chemotherapy in patients with liver failure.
Effect of Posture on Brain Hemodynamics in Preterm Newborns Not Mechanically Ventilated
Authors: Ancora Gina , Maranella Eugenia , Aceti Arianna , Pierantoni Luca , Grandi Sara , Corvaglia Luigi , Faldella Giacomo
Published: October 2009

Background: Changes in head posture influence brain hemodynamics. Optimal positioning has been recommended as 1 of 10 potentially better practices to reduce the incidence of brain injury in preterm newborns. Objectives: The aim of this study was to evaluate by near-infrared spectroscopy (NIRS) the effect of different head and body positions and the influence of gestational age (GA) and nasal continuous positive airway pressure on brain hemodynamics in very preterm newborns. Methods: 24 stable preterm newborns were studied by NIRS in 6 different postures including head rotation and head inclination in both supine and prone positions. Changes in normalized tissue hemoglobin index (nTHI) and tissue oxygenation index (TOI) were measured after posture variations. Results: No statistically significant changes in nTHI and in TOI were found in the 6 postures. nTHI variations, expression of cerebral blood volume variations, were influenced by GA. A reduction in nTHI, with a stable TOI, in the less mature infants (with GA ≤26 weeks), occurred on head rotation; nTHI increased again when the head was derotated. Conclusions: Hemodynamic changes after posture variations depend on GA. Head rotation in newborns with GA ≤26 weeks produced a reduction in nTHI with stable TOI. Possible physiopathological mechanisms are discussed.
Overfeeding Can Cause NEC-Like Enterocolitis in Premature Rat Pups
Authors: Okada Kyo , Fujii Tohru , Ohtsuka Yoshikazu , Yamakawa Yoko , Izumi Hirohisa , Yamashiro Yuichiro , Shimizu Toshiaki
Published: October 2009

Background: Neonatal necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in premature infants. The mortality rate associated with NEC is quite high and in most reports ranges from 20 to 30%. Despite extensive studies, the pathogenesis of NEC remains poorly understood. Objectives: To investigate the mechanisms of NEC in terms of inflammatory signaling in the intestine. Methods: A new enterocolitis model was established and examined the expression of inflammatory and anti-inflammatory signals in the intestines of rat pups. The premature rat pups, delivered by abdominal incision on day 20 of gestation (day 21 is considered as full term), were divided into three groups, and they were given a single administration of 0.05, 0.1, and 0.15 ml of formula milk via an orogastric catheter. After 24 h, the development of enterocolitis was evaluated by the presence of hemorrhagic enterocolitis, and the expression of signaling molecules, inhibitor of nuclear factor-ĸB (IĸB)-α/β and peroxisome proliferator-activated receptor (PPAR)-γ mRNA was examined by reverse transcription-polymerase chain reaction from inflamed and non-inflamed intestinal samples. Results: The incidence of enterocolitis increased with the volume of milk, and 50% of rat pups showed enterocolitis with a volume of 0.15 ml of milk. Expression of IĸB-α/β and PPAR-γ mRNA increased in inflamed intestine. Conclusions: Increased expression of IĸB-α/β suggested that the inflammatory mediator nuclear factor-ĸB is deeply involved in the pathogenesis of enterocolitis that can be easily introduced by overfeeding of milk ingestion in premature rat pups which mimic those seen in NEC. Increased expression of PPAR-γ may possibly regulate further development of enterocolitis in this system.