763 research outputs found
Two-stage rotational disordering of a molecular crystal surface: C60
No full textWe propose a two-stage mechanism for the rotational surface disordering phase transition of a molecular crystal, as realized in C60 fullerite. Our study, based on Monte Carlo simulations, uncovers the existence of a new intermediate regime, between a low-temperature ordered (2×2) state, and a high-temperature (1×1) disordered phase. In the intermediate regime there is partial disorder, strongest for a subset of particularly frustrated surface molecules. These concepts and calculations provide a coherent understanding of experimental observations, with possible extension to other molecular crystal surfaces
Approaches to Brief Intervention for Hazardous Drinking in Young People
No full textThis article represents the proceedings of a symposium at the 2002 joint conference of the Research Society on Alcoholism and the International Society for Biomedical Research on Alcoholism in San Francisco. The chair was John B. Saunders. The focus of the symposium was on brief intervention approaches for hazardous drinking among young people. The presentations were (1) Evidence for the effectiveness of brief intervention as an approach to reducing hazardous alcohol use, by John B. Saunders; (2) College student hazardous drinking in New Zealand, the USA, UK, and Australia: implications for research, policy, and intervention, by Kypros Kypri; (3) Applications of motivational feedback on the college campus, by Scott T. Walters; (4) A population based individualized alcohol harm reduction feedback intervention: preliminary results from the college-based alcohol risk reduction (CBARR) trial, by Robert G. Laforge; and (5) Brief interventions: conclusions and future directions, by Mary E. Larimer
Study of the TFH and B cells dynamic in the spleen and mesenteric lymph node during SIV infection and of the impact of an anti-apoptotic treatment on the dynamic of those cells and on the B cell response in rhesus monkeys infected by SIV
No full textL'infection par le VIH est une pathologie caractérisée par la dissémination du virus dans l'ensemble de l'organisme et une destruction progressive des lymphocytes T CD4+ (LT CD4+) résultant en une immunité altérée. L'épuisement et l'apoptose des cellules T mémoires induites par le virus amènent à l'apparition d'un SIDA. Il a été montré que les centres germinatifs (GCs), structures anatomiques spécialisées au sein des follicules B des organes lymphoïdes secondaires, représentent des lieux privilégiés de la persistance virale. Parmi les organes lymphoïdes, la rate et les ganglions mésentériques seraient des sanctuaires viraux du fait de leur rôle dans la réponse immunitaire. La rate est le principal organe de la réponse B, et les ganglions mésentériques sont essentiels dans l'établissement de la réponse immune mucosale. Les GCs sont principalement constitués de lymphocytes B mais également de lymphocytes T folliculaires (TFH), sous-population de LT CD4+ effecteurs mémoires jouant un rôle essentiel dans le développement de la réponse B, en particulier dans la maturation des anticorps de haute affinité. Des études dont celles du laboratoire ont montré que l'altération de la réponse B observée au cours de l'infection VIH serait due à une perte et à un défaut de différentiation des lymphocytes TFH. Plus récemment, il a été observé que les GCs sont également constitués de lymphocytes T mémoires CD8+ folliculaires (LT CD8+ folliculaires), exprimant le récepteur de chimiokine CXCR5. De récents travaux suggèrent un rôle de ces cellules dans le contrôle de l'infection par le VIH. Le but de ma thèse a été d'étudier la dynamique des lymphocytes TFH au sein de ces deux organes que sont la rate et les ganglions mésentériques, et de déterminer dans quelle mesure l'administration d'un inhibiteur d'apoptose permet de restaurer des fonctions effectrices telle que la production d'anticorps. Ces travaux ont été réalisés chez le macaque rhésus infecté par la souche SIVmac251. Mes résultats montrent que l'infection persistante des ganglions mésentériques est associée à une perte et une altération des follicules B ainsi qu'à une déplétion et une altération des lymphocytes TFH. Ils montrent également une altération de l'expression de la chimiokine CXCL13, ligand de CXCR5, qui serait à même de créer un environnement défavorable à la différenciation des cellules B. Ils montrent aussi que l'administration d'un inhibiteur d'apoptose au cours de la phase de primo-infection chez les singes infectés induit une diminution de l'apoptose des LT CD4+ comme attendu, une diminution des cytokines inflammatoires, et une réponse B systémique spécifique plus importante chez les singes traités. Ceci pourrait contribuer à un meilleur contrôle de la réplication virale. Enfin, mes travaux démontrent qu'au niveau de la rate, on observe une augmentation du nombre de LT CD8+ qui infiltre les follicules B et que ceux-ci n'expriment pas majoritairement la protéine CXCR5 chez les singes infectés en particulier progresseurs. De même, on observe une augmentation de la chimiokine MIP1b, susceptible de jouer un rôle dans le recrutement de LT CD8+ conventionnels chez les singes infectés, et une augmentation de l'expression des marqueurs de cytotoxicité chez les singes non-progresseurs comparativement aux singes progresseurs. Enfin, ces travaux semblent indiquer que les LT CD8+ folliculaires des individus progresseurs ne contrôlent pas l'infection par le VIS. En conclusion, l'infection par le VIS induirait la formation d'un réservoir viral au niveau des follicules B et des GCs induisant une réponse B altérée, associée à une altération des follicules B, à un défaut des lymphocytes TFH, ainsi qu'à un enrichissement en LT CD8+ folliculaires potentiellement défectifs. Ensemble, mes travaux portant sur l'étude des lymphocytes T folliculaires ont mis en exergue et confirmé l'importance de ces cellules T dans les relations hôtes-pathogènes.HIV infection is characterized by a viral spread in the host body and a progressive destruction of CD4+ T cells, leading to a defect in the immune system. The memory T cells apoptosis and exhaustion induced by the virus leads the outcome of an AIDS. It was showed that germinal centers (GCs), specialized anatomical structures present in the B follicles of the secondary lymphoid organs, represent privileged viral reservoir. Among secondary lymphoid organs, spleen and mesenteric lymph nodes would be viral sanctuaries because of their role in the generation of the immune response. Spleen is the main organ of the B cell response, and mesenteric lymph nodes are essentials in the establishment of the mucosal immune response. GCs are mainly composed by B cells but also by TFH cells, a sub-population of effector memory CD4+ T cells, crucial for the generation of the B cell response, especially for the maturation of the highly efficient antibodies. Previous works from our laboratory showed that the defect of the B cell response during HIV infection is due to a loss and a defect of the TFH cells. Recently, it was showed that GCs are also composed of follicular memory CD8+ T cells, expressing the chemokine receptor CXCR5. Recent works suggested that those cells are implicated in the control of HIV infection. Thus, the aim of my thesis was to study the dynamic of follicular T cells in these two organs, spleen and mesenteric lymph nodes, and to set how well the administration of a pan-caspase inhibitor during acute phase of SIV infection help to restore effective functions as the antibody production. Those works were done in rhesus monkeys infected with the strain SIVmav251. My results show that the persistent infection of mesenteric lymph node is associated with a loss and a defect of B follicles and with a defect of TFH cells. They also show a defect in the expression of the CXCL13 chemokine, ligand of the CXCR5 receptor, potentially capable of creating a bad environment for B cell differentiation. My results show also that the administration of a pan-caspase inhibitor during the acute phase of infection leads to a decrease in the CD4+ T cells apoptosis as expected, a decrease in the inflammatory cytokines expression and in a better specific systemic B cell response in treated monkeys. These could help in the control of the viral replication. Finally, my results show that in the spleen, there's an increase of the follicular CD8+ T cells filtering the B follicles, which mainly doesn't express the CXCR5 receptor in infected monkeys, especially the progressor ones. They also show that there's an increase in the expression of the MIP1b chemokine, possibly responsible of the recruitment of conventional CD8+ T cells in the infected monkeys, and an increase in the expression of cytotoxic markers in the non-progressors monkeys compared to the progressors ones. Thus, these work seems to show that follicular CD8+ T cells of progressor monkeys fail to control SIV infection. Thus, SIV infection induce an altered B cell response, associated to a defect of B follicles, a defect of TFH cells, and an increase in follicular CD8+ T cells potentially inefficient. Altogether, my works focused on the study of follicular T cells show and confirm the strength the importance of these T cells in the host-pathogen relationship
Déstabilisation lysosomale précoce au cours de la phase d'engagement des lymphocytes T activés dans l'apoptose (rôle du granzyme B et de la cathepsine D relargués des lysosomes vers le cytosol)
No full textLE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF
Specialization in Small-Scale Societies: The Organization of Pottery Production at Kolomoki (9ER1), Early County, Georgia
No full textInvestigating the organization of production systems can reveal much about a society, in particular how resources and labor were allocated, and the influence that economic, political, social, and ceremonial institutions had on the production process. Interpreting the nature of specialized production is useful for understanding how production was organized. In turn, the degree of standardization exhibited by the goods being produced is used to determine the nature of specialization. While archaeological research regarding specialized production has expanded over time to incorporate a wide range of societies, such research is often focused on complex societies. The research presented here focuses on the small-scale, or non-stratified, community that once inhabited the Kolomoki site, a Middle to Late Woodland period site in Early county, Georgia. This thesis utilizes a three-dimensional laser scanner to document Weeden Island pottery from Kolomoki. The digital images created by the scanner were used to measure incising and punctation marks. The measurements were then analyzed in order to determine the extent of standardization among the decorative attributes. Results suggest that standardization varies among different subsamples of pottery. However, the overall degree of standardization is relatively low, thus suggesting that specialized production may not have existed, or was very limited, at Kolomoki. Despite the limited extent of standardization among the decorative attributes, the results of this research, especially in conjunction with previous research, suggest that some pottery may have been afforded special attention during the production process. In particular, pottery from mound proveniences, and socially valued goods, notably sacred and prestige items, demonstrate higher degrees of standardization. This leads to the conclusion that the production of Weeden Island pottery was likely influenced by ritual and ceremonial activity within the Kolomoki community. This thesis contributes to a greater understanding of specialization in non-stratified Woodland period societies in the southeastern United States
Fortune School class, 1924
No full textFront row, l-r: Harry Jones, Munroe Danforth, Jackie Demerling, Jack LaForge, Harold Garner, J. Whiting. Second row, l-r: Harold Lindroth, Gordon Scott, Bernice Waterson, Marjorie McMahon, Jean Lindroth, Evelyn Scott, Vi Freeman, Jean MacKay, Tom Watt. Third row, l-r: Greta Nelson, unknown, Roberta Blackburn, [Effie?] Birrell, George Carefoot, [Isabel ?] Birrell, B. Dale, B. Clarke. Fourth row, l-r: Charlie Dugdale, unknown male, Ole Nelson, Hugh Belamy, Glen Waterson, Jack Dugdale. Teacher: Miss L. Woods
Search for Extra Space-Dimensions at the LHC
No full text7 pages, 6 figuresThe introduction of extra space dimensions in the theory could be an elegant way tovsolve the hierarchy problem. There could even be one energy scale at which all interactions could unify. The limits coming from our knowledge of the gravitation at low distance allow this energy scale to be as low as few TeV. This situation is extremely interesting experimentally in the context of the LHC which will cover the range from 100 GeV to few TeV. This article describes the different analyses developed by the LHC experiments to study this new phenomenology
Search for Extra Space-Dimensions at the LHC
No full text7 pages, 6 figuresThe introduction of extra space dimensions in the theory could be an elegant way tovsolve the hierarchy problem. There could even be one energy scale at which all interactions could unify. The limits coming from our knowledge of the gravitation at low distance allow this energy scale to be as low as few TeV. This situation is extremely interesting experimentally in the context of the LHC which will cover the range from 100 GeV to few TeV. This article describes the different analyses developed by the LHC experiments to study this new phenomenology
Search for a Low Mass Standard Model Higgs Boson with the ATLAS Detector at the LHC
No full textIn 2011, the ATLAS experiment collected ~4.8 fb-1 of proton-proton collision data at √s = 7 TeV provided by the Large Hadron Collider (LHC). This data set allowed the search for a Standard Model (SM) Higgs Boson in the TeV range. In that paper, the focus is put on the searches of a low mass Higgs in the range [110, 150] GeV. Using the 2011 ATLAS dataset, the combination of all the channels showed that a SM Higgs boson was restricted to live in the region 117.5-118.5 and 122.5-129 GeV. Importantly, an excess of events was observed around 126 GeV but its statistical significance was too small (2.5 standard deviations) to be able to conclude to any discovery yet at the time of the presentation made at the CIPANP2012 conference [1]. These results have been updated in July 4th 2012 using the 2011 dataset and around 5.8 fb-1 of proton-proton collision data at √s = 8 TeV collected in 2012. The present conclusion is that the excess is now significant enough (5.9 standard deviations) to announce the discovery of a new neutral particle with a mass of M=126.0 GeV +/-0.4 GeV (stat.) +/- 0.4 GeV (syst.) whose properties are compatible with those expected from a SM Higgs boson [2]. These proceedings will then describe the published results
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