Evidences of the cooperative role of the chemokines CCL3, CCL4 and CCL5 and its receptors CCR1+and CCR5+in RANKL+ cell migration throughout experimental periodontitis in mice

Periodontal disease (PD) is characterized by the inflammatory bone resorption in response to the bacterial challenge, in a host response that involves a series of chemokines supposed to control cell influx into periodontal tissues and determine disease outcome. In this study, we investigated the role of chemokines and its receptors in the immunoregulation of experimental PD in mice. Aggregatibacter actinomycetemcomitans-infected C57BI/6 (WT) mice developed an intense inflammatory reaction and severe alveolar bone resorption, associated with a high expression of CCL3 and the migration of CCR5+, CCR1+ and RANKL+ cells to periodontal tissues. However, CCL3KO-infected mice developed a similar disease phenotype than WT strain, characterized by the similar expression of cytokines (TNF-alpha, IFN-gamma and IL-10), osteoclastogenic factors (RANKL and OPG) and MMPs (MMP-1, MMP-2, MMP-3, TIMP-1 and TIMP-3), and similar patterns of CCR1+, CCR5+ and RANKL+ cell migration. The apparent lack of function for CCL3 is possible due the relative redundancy of chemokine system, since chemokines such as CCL4 and CCL5, which share the receptors CCR1 and CCR5 with CCL3, present a similar kinetics of expression than CCL3. Accordingly, CCL4 and CCL5 kinetics of expression after experimental periodontal infection remain unaltered regardless the presence/absence of CCL3. Conversely, the individual absence of CCR1 and CCR5 resulted in a decrease of leukocyte infiltration and alveolar bone loss. When CCR1 and CCR5 were simultaneously inhibited by met-RANTES treatment a significantly more effective attenuation of periodontitis progression was verified, associated with lower values of bone loss and decreased counts of leukocytes in periodontal tissues. Our results suggest that the absence of CCL3 does not affect the development of experimental PD in mice, probably due to the presence of homologous chemokines CCL4 and CCL5 that overcome the absence of this chemokine. In addition, our data demonstrate that the absence of chemokine receptors CCR1+ and CCR5+ attenuate of inflammatory bone resorption. Finally, our data shows data the simultaneous blockade of CCR1 and CCR5 with MetRANTEs presents a more pronounced effect in the arrest of disease progression, demonstrating the cooperative role of such receptors in the inflammatory bone resorption process throughout experimental PD. (C) 2009 Elsevier Inc. All rights reserved.

Poly-bagging predictors for classification modelling for credit scoring

Credit scoring modelling comprises one of the leading formal tools for supporting the granting of credit. Its core objective consists of the generation of a score by means of which potential clients can be listed in the order of the probability of default. A critical factor is whether a credit scoring model is accurate enough in order to provide correct classification of the client as a good or bad payer. In this context the concept of bootstraping aggregating (bagging) arises. The basic idea is to generate multiple classifiers by obtaining the predicted values from the fitted models to several replicated datasets and then combining them into a single predictive classification in order to improve the classification accuracy. In this paper we propose a new bagging-type variant procedure, which we call poly-bagging, consisting of combining predictors over a succession of resamplings. The study is derived by credit scoring modelling. The proposed poly-bagging procedure was applied to some different artificial datasets and to a real granting of credit dataset up to three successions of resamplings. We observed better classification accuracy for the two-bagged and the three-bagged models for all considered setups. These results lead to a strong indication that the poly-bagging approach may promote improvement on the modelling performance measures, while keeping a flexible and straightforward bagging-type structure easy to implement. (C) 2011 Elsevier Ltd. All rights reserved.

Cooperative scattering by cold atoms

We have studied the interplay between disorder and cooperative scattering for the single scattering limit in the presence of a driving laser. Analytical results have been derived and we have observed cooperative scattering effects in a variety of experiments, ranging from thermal atoms in an optical dipole trap, atoms released from a dark MOT and atoms in a BEC, consistent with our theoretical predictions.

Modification of radiation pressure due to cooperative scattering of light

Cooperative spontaneous emission of a single photon from a cloud of N atoms modifies substantially the radiation pressure exerted by a far-detuned laser beam exciting the atoms. On one hand, the force induced by photon absorption depends on the collective decay rate of the excited atomic state. On the other hand, directional spontaneous emission counteracts the recoil induced by the absorption. We derive an analytical expression for the radiation pressure in steady-state. For a smooth extended atomic distribution we show that the radiation pressure depends on the atom number via cooperative scattering and that, for certain atom numbers, it can be suppressed or enhanced. Cooperative scattering of light by extended atomic clouds can become important in the presence of quasi-resonant light and could be addressed in many cold atoms experiments.

The binding of synthetic triiodo L-thyronine analogs to human transthyretin: Molecular basis of cooperative and non-cooperative ligand recognition

Transthyretin (TTR) is a tetrameric beta-sheet-rich transporter protein directly involved in human amyloid diseases. Several classes of small molecules can bind to TTR delaying its amyloid fibril formation, thus being promising drug candidates to treat TTR amyloidoses. In the present study, we characterized the interactions of the synthetic triiodo L-thyronine analogs and thyroid hormone nuclear receptor TR beta-selecfive agonists GC-1 and GC-24 with the wild type and V30M variant of human transthyretin (TTR). To achieve this aim, we conducted in vitro TTR acid-mediated aggregation and isothermal titration calorimetry experiments and determined the TTR:GC-1 and TTR:GC-24 crystal structures. Our data indicate that both GC-1 and GC-24 bind to TTR in a non-cooperative manner and are good inhibitors of TTR aggregation, with dissociation constants for both hormone binding sites (HBS) in the low micromolar range. Analysis of the crystal structures of TTRwt:GC-1(24) complexes and their comparison with the TTRwt X-ray structure bound to its natural ligand thyroxine (T4) suggests, at the molecular level, the basis for the cooperative process displayed by T4 and the non-cooperative process provoked by both GC-1 and GC-24 during binding to TTR. (C) 2010 Elsevier Inc. All rights reserved.

Review of the literature on credit risk modeling : development of the past 10 years

This paper traces the developments of credit risk modeling in the past 10 years. Our work can be divided into two parts: selecting articles and summarizing results. On the one hand, by constructing an ordered logit model on historical Journal of Economic Literature (JEL) codes of articles about credit risk modeling, we sort out articles which are the most related to our topic. The result indicates that the JEL codes have become the standard to classify researches in credit risk modeling. On the other hand, comparing with the classical review Altman and Saunders(1998), we observe some important changes of research methods of credit risk. The main finding is that current focuses on credit risk modeling have moved from static individual-level models to dynamic portfolio models.

February 2002: Futures, Part III, Cooperative Ventures and Services

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November 2001: P.A.S.C.A.L: The Cooperative Spirit

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Developing a Credit for Prior Learning Program: System-Wide Strategies for Program Creation, Operations, and Recruitment

Credit for prior learning programs help students complete degrees more quickly and for less money. This report addresses the challenges of scaling up a credit for prior learning program at the university system level, and explores the delineation of responsibilities between system staff and institutional staff.

Essays on credit and bankruptcy law

This thesis is composed of four papers referent to the subject of Credit and Bankruptcy Law. In each essay - that corresponds to one chapter - we aim at analyzing the ináuence of default on credit market, considering di§erent legal situations.

O modelo de integração econômico e social nas cooperativas agropecuárias do Paraná

Analisar o modelo de integração das cooperativas de produtores agropecuários no estado do Paraná foi o propósito deste estudo. Foram estudadas as características, os fatores que dificultam e as ações que facilitam a integração entre cooperados e suas cooperativas e destas entre si. As cooperativas têm características distintas dos outros atores do mercado, nos seus objetivos, na forma de gestão, na formação do capital e na sua identificação com a comunidade onde atuam. O desenvolvimento das cooperativas agropecuárias no Paraná é resultante dos Projetos Integrados de Cooperativismo (PICs), implementados a partir de 1972. O modelo previa cooperativas singulares, cada qual com sua área de ação, com o objetivo de proporcionar assistência técnica, creditícia e apoio logístico aos produtores associados, e centrais cooperativas, por região, para industrialização e comercialização da produção. Os resultados proporcionados pelos projetos integrados são evidentes, pois, quase 60% da produção agropecuária atual provém das cooperativas em todo o estado. Porém, ao longo do tempo, em razão do crescimento desigual das cooperativas, surgiram disputas por área de ação entre cooperativas e conflitos de interesses em relação às centrais que comprometeram o modelo de integração idealizado. Pesquisa de campo realizada para este estudo, mostra que 75% das pessoas que compõem o público interno das cooperativas – cooperados, dirigentes e funcionários, concordam que há concorrência entre cooperativas no Paraná. Trata-se de tema polêmico porém relevante para o desenvolvimento do cooperativismo paranaense, que concorre com grandes conglomerados econômicos nacionais e internacionais. A superação do dilema da integração constitui importante desafio às organizações cooperativas. Esta dissertação utiliza metodologia de análise de conteúdo, descrita por VERGARA (2007, p. 15) para extrair da bibliografia e da pesquisa de campo os resultados almejados. Com base na Teoria da Delimitação dos Sistemas Sociais, concebida por Guerreiro Ramos (1981), conclui-se que as cooperativas agropecuárias paranaenses são organizações de interesse econômico que apresentam características isonômicas de gestão. A maioria dos fatores que dificultam a integração nas cooperativas é originada de atitudes internas de cooperados e dirigentes, tais como: individualismo, falta de conhecimento sobre as cooperativas e falta de interesse em participar da cooperativa. Entre as ações que poderiam contribuir para a integração foi citada a necessidade de se constituir novo modelo de integração, apoiado por programas de educação, comunicação e capitalização em volumes compatíveis com as demandas dos projetos das cooperativas, tanto aos cooperados quanto para projetos integrados entre cooperativas.