Academic literature on the topic '872nd'

The aim of this study was to determine the coefficients of the Goettingen model for Redbro birds and estimate the digestible lysine requirements. To determine the model parameters, three nitrogen balance trials were performed in Periods I (14–28 days), II (42–56 days) and III (70–84 days), using 42 birds per trial. The birds were individually housed and subjected to six diets with increasing levels of nitrogen, with lysine as the limiting amino acid (deficient by 20% in relation to other amino acids). Dietary nitrogen concentrations were 8, 16, 24, 32, 40 and 48 g/kg. A control diet was added to confirm lysine as the first limiting amino acid. Nitrogen balance trials were divided into 5 days of adaptation and two periods of excreta collection, each one of 5 days. The response of the birds to a control diet confirmed that lysine was the first limiting amino acid. The adjustment of the exponential functions between nitrogen retention or excretion and nitrogen intake allowed estimation of parameters of the Goettingen model. The maximum potential for nitrogen retention was 3276, 2585 and 2603 mg/BWkg0.67.day, nitrogen maintenance requirement was 225, 135 and 122 mg/BWkg0.67.day and efficiency of nitrogen utilisation was 313 × 10−6, 406 × 10−6 and 415 × 10−6 in the phases of 14–28, 42–56 and 70–84 days. The digestible lysine intake for Periods I, II and III, based on 60% of the maximum potential for nitrogen retention, was 711, 989 and 1272 mg/day (1.225%, 1.137% and 1.09% of lysine in the diet for a daily feed intake of 58, 87and 117 g/day), respectively.

Abstract Introduction: Transfusion-dependent hemolytic anemias particularly thalassemia major (thal.m) and also sickle cell disease (SCD) result in iron deposition in the reticuloendothelial system in major organs, mainly in the liver and also in the heart and endocrine glands. However, liver iron levels in patients with thal.m measured by other techniques were found to have no predictive values for the extent of their cardiac iron deposition. T2* MRI sequences have been previously addressed as a reliable tool for non invasive evaluation of iron load in the liver, heart and pancreas. Patients with T2* value > 20 ms have normal cardiac function while the prevalence of myocardial dysfunction and arrhythmias increases as a consequence of cardiac iron overload (T2* < 20 ms). A previous study comparing cardiac iron overload in transfusion dependent thal.m and SCD patients matched for age and liver iron content, found abnormally low cardiac T2* values (<20 ms) in nearly 40% of patients with thal.m, while the T2* values were normal in the patients with SCD (1) (Blood:103;1934, 2004). The purpose of the present study was to quantify iron content (T2* values) in the liver, heart and pancreas of multitransfused patients with sickle/β-thal. Patients and Methods: Eleven patients with sickle/β-thal., 3 males and 8 females, mean age 31 years ± 9.5 (SD) were analyzed, 6 of them were splenectomized. Their mean ± SD values for hemoglobin was 9.0 gr/dl, for serum ferritin - 3900 ng/ml ± 3944 and for transferrin saturation - 80% ± 23. All of them were transfused and received a mean of 97 packed cell units ± 88 (SD). Only one patient received iron chelation for 10 months until 6 months prior to entering the study. Seven patients received regularly Hydrea 1–1.5 gr/day for > 10 years. MRI evaluation (1.5T, GE MRI system) included: Left ventricular (LV) function (ejection fraction)- steady-state free procession (SSFP) cine sequence as well as iron load quantification- breath-hold multi echo gradient echo T2*, sampled across regions of interest in the LV septum, liver parenchyma and pancreatic tissue. (Eur. Heart J22:2171, 2001) Results: All patients had normal T2* values in the heart (>20ms) and in the pancreas (>30ms). The left ventricular ejection fraction, left ventricular endsystolic and endiastolic volumes (evaluated both by echo-cardiography and by cine function MRI) were normal in all patients. There was no evidence for pleural or pericardial effusion. The diameter of the pulmonary artery and right ventricle were normal. Seven patients demonstrated evidence of mild to moderate iron deposition in the liver (T2* <6.3 ms). In these patients mean serum ferritin (5656 ng/ml) and transferrin saturation (92.4%) were significantly higher (p=0.001) than in 4 patients with normal T2* levels in the liver (>6.3ms) where mean serum ferritin was 872ng/ml and transferrin saturation 59.5%. Conclusion: The T2* MRI values of 11 patients with sickle/β-thal. showed that whereas 7 patients had a certain degree of iron deposition in the liver, none demonstrated cardiac or pancreatic iron deposition. Therefore, with respect to iron deposition, multitransfused patients with sickle/β-thal. are similar to patients with homozygous SCD and not to patients with thal.m and thal intermedia. The reasons for this observation are still unclear. This similarity could be related in part to the relativly low number of transfusions, starting later in life, of patients with homozygous SCD or sickle/β- thal. compared to patients with thal.m. (1) The liver is the dominant iron storage organ and iron liver concentration correlates closely with the total body iron content. While iron uptake by hepatocytes is predominately mediated via transferrin and correlates with serum ferritin levels, as confirmed in the present study, this is not the case in regulation of cardiac and endocrine iron uptake. These organs might acquire the excess metal differently. It is possible that additional and/or different forms of iron, which have been identified, such as non-transferrin bound iron and labile plasma iron, are involved in determining iron loading in the heart and endocrine glands and/or because regulation of iron entry into the plasma by hepcidin might differ. Additional studies are in progress to address these issues.

The role of mechanical force has gained increasing interest in the field of cell biology owing to the realisation that cells are continually subject to stresses and strains induced by the cellular environment. Cells are known to be able to sense and react to forces imposed on them by their local environment as well as being able to directly impart force during motility, adhesion and cell division. This is also true for cells of the adaptive immune system, specifically during the intimate cell-cell interaction occurring between the T-cell and Antigen Presenting Cell (APC), known as the Immunological Synapse (IS). This highly selective process by which a T cell is able to bind, recognise and react to only foreign antigens has been the focus of intense study due to its crucial importance in the adaptive immune response. The actin cytoskeleton is known to play an essential role in the formation and maintenance of the IS, but questions remain regarding the influence of forces generated by actin during this process. With the aim of measuring mechanical force generated at the IS, we present a novel method combining the super resolution imaging technique, Stimulated Emission Depletion (STED) microscopy and Traction Force Microscopy (TFM). Using the tunable kinetics of the 1G4 Jurkat T-cell system in combination with high spatial and temporal resolution microscopy we demonstrate that actin dynamics at the IS is antigen dependent and show by TFM that force generation occurs on two distinct time scales during activation, mediated by the actin cytoskeleton. Together, the results highlight the intimate links between the dynamics of the actin cytoskeleton, force generation and the antigen response of T cells during activation.

Cette thèse propose une arithmétique pratique de calcul d’intervalles et quantités floues. Ces derniers sont modélisés, non pas par leurs fonctions d’appartenance classiques, mais par une fonction de répartition cumulée inspirée des statistiques. Cette proposition se veut innovante et pratique pour traiter des données imprécises et incertaines avec l’introduction de quelques idées dans ce sens. Cette approche n’a pas évidement pour objectif de remettre en cause un certain nombre de méthodes existantes dans la littérature, mais offre une autre manière de raisonner et de résoudre certaines problématiques avec une implémentation et modélisation plus simples. La proximité de cette méthode avec les probabilités et les statistiques classiques a conduit à mettre un accent sur des applications d’analyse de données imprécises, et à une extension des outils statistiques. Néanmoins, une arithmétique assez riche et cohérente basée sur les techniques de la logique floue et du calcul par intervalles a été proposée. De nombreux exemples didactiques sont présentés au cours de ce travail pour faciliter la compréhension de notre démarche. Le but de ce mémoire est de démontrer dans un premier temps la faisabilité et l’applicabilité de nos propositions. Les résultats des applications, que ce soit en analyse de données objectives et subjectives, ou bien en commande à modèle interne des systèmes non linéaires (avec notamment une application en temps réel sur un système non linéaire et imprécis), montrent l’intérêt du f-calcul. D’autres développements mathématiques et extensions aux autres domaines laissent augurer des perspectives intéressantes dans un futur proche
The presented Ph. D. Thesis proposes a practical arithmetic to calculate fuzzy intervals and quantities. The latter are modelled by an accumulative distribution function based on classical statistics instead of classical membership functions. This innovative work effectively deals with imprecise data and uncertainties by exploiting some ideas in the direction described above. Existing methods found in the specialized literature are not disregarded, though this thesis intends to present another way of reasoning and solving certain problems with a simpler implementation. Since the proposed method is close to probability and classical statistics, it has lead –at a first stage-to stressing the analysis of imprecise data as well as to extend the statistical tools. Nevertheless, a complete and coherent arithmetic based on fuzzy logic techniques and interval analysis has been proposed. A number of illustrative examples have been presented through this work to facilitate the understanding of our approach. The thesis’ objective is to show the feasibility and applicability of our claims. Results obtained in applications, both on the analysis of objective-subjective data and on the internal nonlinear model control (with special emphasis on a real-time application for a non-linear imprecise system) have proved the effectiveness of j-calculus. Other mathematical developments and extensions to other areas suggest that interesting perspectives in the future will arrive

Située au nord de l’Islande, la région littorale du Skagafjörður a connu, au cours de la déglaciation du Weichsélien Tardif, une fonte massive des édifices glaciaires. Cette période de déglaciation a eu des impacts importants sur les reliefs et les dynamiques de versant. Les instabilités qui ont affecté les versants au cours de cette séquence s’expriment selon deux modalités principales : (i) les réajustements par déformation (i. E. Les étalements gravitaires) et (ii) les réajustements par glissement (i. E. Les mouvements de masse). C’est à l’étude de ces réajustements de versants qui opèrent en contexte de déglaciation qu’est consacrée cette thèse. A ce titre, elle s’inscrit dans le cadre de la géomorphologie paraglaciaire qui a pour objet les « processus de surface, formations, formes et géosystèmes qui sont directement conditionnés par la glaciation et la déglaciation » (Ballantyne, 2002). Ces réajustements paraglaciaires de versant sont abordés autour de deux questions : (i) le rôle de la déglaciation dans la mise en place des réajustements de versants et (ii) le rôle des réajustements de versants dans le façonnement des auges et des cirques glaciaires. Les résultats des recherches réalisés dans le cadre de cette thèse font apparaître : (i) une influence significative des instabilités paraglaciaires de versant (i. E mouvements de masse et étalements gravitaires) dans le façonnement et l’érosion des reliefs des milieux froids et (ii) un rôle potentiel de la dynamique d’étalement gravitaire dans la dégradation progressive de la stabilité des pentes en contexte de déglaciation qui conduit, in fine, au déclenchement des mouvements de masse
Located north of Iceland, the Skagafjörður area has experienced an ice shrinking during the Late Weichselian deglaciation. This period of transition from glacial to non-glacial conditions was characterized by significant impacts on reliefs and slope dynamics. The slope instabilities induced by the deglaciation operate in the form of: (i) slope deformations (i. E. Gravitational spreading) and (ii) slope failures (i. E. Mass-movements). This thesis is devoted to these slope readjustments which occurred in context of deglaciation. Accordingly, the thesis is related to the paraglacial geomorphology which focuses on “non glacial earth surface processes, sediment accumulations, landforms, landsystems and landscapes that are directly conditioned by glaciation and deglaciation” (Ballantyne, 2002). Two major uncertainties remains about: (i) the relationship between slope instabilities, both in the form of gravitational spreading and mass-movement, and the sequence of deglaciation, and (ii) the influence of paraglacial slope instabilities in the shaping of the erosional landforms usually attributed to the action of glacial erosion processes (i. E. Cirques and troughs). Main results carried out during this research highlight: (i) a significant influence of paraglacial gravitational spreading and mass-movement respectively in the carving of troughs and cirques and (ii) a potential influence of gravitational spreading as a precursor of mass-movement, throughout the progressive degradation of slope stability induced by the gravitational deformation which may ultimately result in rock-slope failures