993 resultados para specific load
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This guide provides a summary of the factors and design theories that should be considered when designing dowel load transfer systems for concrete pavement systems (including dowel basket design and fabrication) and presents recommendations for widespread adoption (i.e., standardization). Development of the guide was sponsored by the National Concrete Consortium with the goal of helping practitioners develop and implement dowel load transfer designs based on knowledge about current research and best practices.
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The thermodynamic functions of a Fermi gas with spin population imbalance are studied in the temperature-asymmetry plane in the BCS limit. The low-temperature domain is characterized by an anomalous enhancement of the entropy and the specific heat above their values in the unpaired state, decrease of the gap and eventual unpairing phase transition as the temperature is lowered. The unpairing phase transition induces a second jump in the specific heat, which can be measured in calorimetric experiments. While the superfluid is unstable against a supercurrent carrying state, it may sustain a metastable state if cooled adiabatically down from the stable high-temperature domain. In the latter domain the temperature dependence of the gap and related functions is analogous to the predictions of the BCS theory.
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In a recent vaccination trial assessing the immunogenicity of an NY-ESO-1 (ESO) recombinant protein administered with Montanide and CpG, we have obtained evidence that this vaccine induces specific cytolytic T lymphocytes (CTL) in half of the patients. Most vaccine-induced CTLs were directed against epitopes located in the central part of the protein, between amino acids 81 and 110. This immunodominant region, however, is distinct from another ESO CTL region, 157-165, that is a frequent target of spontaneous CTL responses in A2+ patients bearing ESO tumors. In this study, we have investigated the CTL responses to ESO 157-165 in A2+ patients vaccinated with the recombinant protein. Our data indicate that after vaccination with the protein, CTL responses to ESO 157-165 are induced in some, but not all, A2+ patients. ESO 157-165-specific CTLs induced by vaccination with the ESO protein were functionally heterogeneous in terms of tumor recognition and often displayed decreased tumor reactivity as compared with ESO 157-165-specific CTLs isolated from patients with spontaneous immune responses to ESO. Remarkably, protein-induced CTLs used T-cell receptors similar to those previously isolated from patients vaccinated with synthetic ESO peptides (Vbeta4.1) and distinct from those used by highly tumor-reactive CTLs isolated from patients with spontaneous immune responses (Vbeta1.1, Vbeta8.1, and Vbeta13.1). Together, these results demonstrate that vaccination with the ESO protein elicits a repertoire of ESO 157-165-specific CTLs bearing T-cell receptors that are structurally distinct from those of CTLs found in spontaneous immune responses to the antigen and that are heterogeneous in terms of tumor reactivity, being often poorly tumor reactive.
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Signaling through the Notch1 receptor is essential for the control of numerous developmental processes during embryonic life as well as in adult tissue homeostasis and disease. Since the outcome of Notch1 signaling is highly context-dependent, and its precise physiological and pathological role in many organs is unclear, it is of great interest to localize and identify the cells that receive active Notch1 signals in vivo. Here, we report the generation and characterization of a BAC-transgenic mouse line, N1-Gal4VP16, that when crossed to a Gal4-responsive reporter mouse line allowed the identification of cells undergoing active Notch1 signaling in vivo. Analysis of embryonic and adult N1-Gal4VP16 mice demonstrated that the activation pattern of the transgene coincides with previously observed activation patterns of the endogenous Notch1 receptor. Thus, this novel reporter mouse line provides a unique tool to specifically investigate the spatial and temporal aspects of Notch1 signaling in vivo. genesis 50:700-710, 2012. © 2012 Wiley Periodicals, Inc.
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It was hypothesized that the EBV-specific CD8(+) T cell response may be dysregulated in multiple sclerosis (MS) patients, possibly leading to a suboptimal control of this virus. To examine the CD8(+) T cell response in greater detail, we analyzed the HLA-A2-, HLA-B7-, and HLA-B8-restricted EBV- and CMV-specific CD8(+) T cell responses in a high number of MS patients and control subjects using tetramers. Content in cytolytic granules, as well as cytotoxic activity, of EBV- and CMV-specific CD8(+) T cells was assessed. We found that MS patients had a lower or a higher prevalence of HLA-A2 and HLA-B7, respectively. Using HLA class I tetramers in HLA-B7(+) MS patients, there was a higher prevalence of MS patients with HLA-B*0702/EBV(RPP)-specific CD8(+) T cells ex vivo. However, the magnitude of the HLA-B*0702/EBV(RPP)-specific and HLA-B*0702/CMV(TPR)-specific CD8(+) T cell response (i.e., the percentage of tetramer(+) CD8(+) T cells in a study subject harboring CD8(+) T cells specific for the given epitope) was lower in MS patients. No differences were found using other tetramers. After stimulation with the HLA-B*0702/EBV(RPP) peptide, the production of IL-2, perforin, and granzyme B and the cytotoxicity of HLA-B*0702/EBV(RPP)-specific CD8(+) T cells were decreased. Altogether, our findings suggest that the HLA-B*0702-restricted viral (in particular the EBV one)-specific CD8(+) T cell response is dysregulated in MS patients. This observation is particularly interesting knowing that the HLA-B7 allele is more frequently expressed in MS patients and considering that EBV is associated with MS.
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BACKGROUND: Mutations in the sulfate transporter gene SLC26A2 (DTDST) cause a continuum of skeletal dysplasia phenotypes that includes achondrogenesis type 1B (ACG1B), atelosteogenesis type 2 (AO2), diastrophic dysplasia (DTD), and recessive multiple epiphyseal dysplasia (rMED). In 1972, de la Chapelle et al reported two siblings with a lethal skeletal dysplasia, which was denoted "neonatal osseous dysplasia" and "de la Chapelle dysplasia" (DLCD). It was suggested that DLCD might be part of the SLC26A2 spectrum of phenotypes, both because of the Finnish origin of the original family and of radiographic similarities to ACG1B and AO2. OBJECTIVE: To test the hypothesis whether SLC26A2 mutations are responsible for DLCD. METHODS: We studied the DNA from the original DLCD family and from seven Finnish DTD patients in whom we had identified only one copy of IVS1+2T>C, the common Finnish mutation. A novel SLC26A2 mutation was found in all subjects, inserted by site-directed mutagenesis in a vector harbouring the SLC26A2 cDNA, and expressed in sulfate transport deficient Chinese hamster ovary (CHO) cells to measure sulfate uptake activity. RESULTS: We identified a hitherto undescribed SLC26A2 mutation, T512K, homozygous in the affected subjects and heterozygous in both parents and in the unaffected sister. T512K was then identified as second pathogenic allele in the seven Finnish DTD subjects. Expression studies confirmed pathogenicity. CONCLUSIONS: DLCD is indeed allelic to the other SLC26A2 disorders. T512K is a second rare "Finnish" mutation that results in DLCD at homozygosity and in DTD when compounded with the milder, common Finnish mutation.
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Expression of the cancer/germ-line antigen NY-ESO-1 by tumors elicits spontaneous humoral and cellular immune responses in some cancer patients. Development of vaccines capable of stimulating such comprehensive immune responses is desirable. We have produced recombinant lentivectors directing the intracellular synthesis of NY-ESO-1 (rLV/ESO) and have analyzed the in vivo immune response elicited by this vector. Single injection of rLV/ESO into HLA-A2-transgenic mice elicited long-lasting B and T cell responses against NY-ESO-1. CD8+ T cells against the HLA-A2-restricted peptide NY-ESO-1(157-165) were readily detectable ex vivo and showed restricted TCR Vbeta usage. Moreover, rLV/ESO elicited a far greater anti-NY-ESO-1(157-165) CD8+ T cell response than peptide- or protein-based vaccines. Anti-NY-ESO-1 antibodies were rapidly induced after immunization and their detection preceded that of the antigen-specific CD8+ T cells. The rLV/ESO also induced CD4+ T cells. These cells played an essential role as their depletion completely abrogated B cell and CD8+ T cell responses against NY-ESO-1. The induced CD4+ T cells were primarily directed against a single NY-ESO-1 epitope spanning amino acids 81-100. Altogether, our study shows that rLV/ESO induces potent and comprehensive immune responses in vivo.
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Knowledge of the quantitative genetics of resistance to parasitism is key to appraise host evolutionary responses to parasite selection. Here, we studied effects of common origin (i.e. genetic and pre-hatching parental effects) and common rearing environment (i.e. post-hatching parental effects and other environment effects) on variance in ectoparasite load in nestling Alpine swifts (Apus melba). This colonial bird is intensely parasitized by blood sucking louse-flies that impair nestling development and survival. By cross-fostering half of the hatchlings between pairs of nests, we show strong significant effect of common rearing environment on variance (90.7% in 2002 and 90.9% in 2003) in the number of louse-flies per nestling and no significant effect of common origin on variance in the number of louse-flies per nestling. In contrast, significant effects of common origin were found for all the nestling morphological traits (i.e. body mass, wing length, tail length, fork length and sternum length) under investigation. Hence, our study suggests that genetic and pre-hatching parental effects play little role in the distribution of parasites among nestling Alpine swifts, and thus that nestlings have only limited scope for evolutionary responses against parasites. Our results highlight the need to take into consideration environmental factors, including the evolution of post-hatching parental effects such as nest sanitation, in our understanding of host-parasite relationships.
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BACKGROUND: Post-transplant lymphoproliferative disease (PTLD) is a life-threatening complication of immunosuppression following transplantation. Epstein-Barr virus (EBV) and gammopathy in serum are associated with PTLD, but these two parameters have not been evaluated in parallel for their association with PTLD. METHODS: We evaluated the incidence of EBV load positivity, gammopathy, and protein expression in sera from all PTLD patients diagnosed at our hospital during the past seven yr. Results were compared with those of a control group including matched transplanted patients who did not develop PTLD. RESULTS: Seven of 10 PTLD patients presented EBV(+) PTLD, for which five patients had detectable serum EBV DNA levels compared with none of 38 controls (RR between two groups =121, p < 0.0001). Five out of 10 patients had gammopathy at PTLD diagnosis compared with 5/38 controls (RR between two groups = 6.6, p = 0.022). Additionally, protein serum analysis by high-resolution two-dimensional gel electrophoresis and image examination failed to evidence specific abnormality in patients with PTLD compared with controls. CONCLUSIONS: Our results confirm an association between EBV in sera and gammopathy with PTLD, and highlight the high specificity of the former analysis. Whether a combination of both analyses will improve the clinical detection of PTLD remains to be evaluated in a larger prospective cohort study.
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Birds exhibit exceptional longevity and are thus regarded as a convenient model to study the intrinsic mechanisms of aging. The oxidative stress theory of aging suggests that individuals age because molecules, cells, tissues, organs, and, ultimately, animals accumulate oxidative damage over time. Accumulation of damage progressively reduces the level of antioxidant defences that are expected to decline with age. To test this theory, we measured the resistance of red blood cells to free radical attack in a captive population of greater flamingo (Phoenicopterus ruber roseus) of known age ranging from 0.3 to 45 years. We observed a convex relationship with young adults (12-20 years old) having greater resistance to oxidative stress than immature flamingos (5 months old) and old flamingos (30-45 years old). Our results suggest that the antioxidant detoxifying system must go through a maturation process before being completely functional. It then declines in older adults, supporting the oxidative theory of aging. Oxidative stress could hence play a significant role in shaping the pattern of senescence in a very long-lived bird species.
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Ability to induce protein expression at will in a cell is a powerful strategy used by scientists to better understand the function of a protein of interest. Various inducible systems have been designed in eukaryotic cells to achieve this goal. Most of them rely on two distinct vectors, one encoding a protein that can regulate transcription by binding a compound X, and one hosting the cDNA encoding the protein of interest placed downstream of promoter sequences that can bind the protein regulated by compound X (e.g., tetracycline, ecdysone). The commercially available systems are not designed to allow cell- or tissue-specific regulated expression. Additionally, although these systems can be used to generate stable clones that can be induced to express a given protein, extensive screening is often required to eliminate the clones that display poor induction or high basal levels. In the present report, we aimed to design a pancreatic beta cell-specific tetracycline-inducible system. Since the classical two-vector based tetracycline-inducible system proved to be unsatisfactory in our hands, a single vector was eventually designed that allowed tight beta cell-specific tetracycline induction in unselected cell populations.
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The autosomal recessive forms of limb-girdle muscular dystrophies are encoded by at least five distinct genes. The work performed towards the identification of two of these is summarized in this report. This success illustrates the growing importance of genetics in modern nosology.
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Vitiligo, a skin disorder characterized by the spontaneous destruction of melanocytes, is believed to be of autoimmune origin. We investigated the presence and functionality of CD8(+) T-cells specific for the melanocyte-associated antigens Melan-A, gp100, tyrosinase, and TRP-2 in the blood of HLA-A2(+) vitiligo patients. We enumerated antigen-specific CD8(+) T cells by major histocompatibility complex multimer staining directly ex vivo, as well as after 9 days of in vitro stimulation and assessed IFN-gamma secretion by enzyme-linked immunospot (Elispot) assay. Tyrosinase-, gp100-, or TRP-2-specific CD8(+) T cells could not be identified in the peripheral blood of individuals with vitiligo. Although Melan-A-specific T cells were detectable at levels comparable to Flu-MP-specific T cells by multimer staining, these lymphocytes did not express the skin-homing receptor cutaneous lymphocyte antigen, were phenotypically naïve (CD45RA(+)), and were unresponsive in the IFN-gamma Elispot assay, suggesting that they are unlikely to be involved in the etiopathogenesis of vitiligo.
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Estimation of soil load-bearing capacity from mathematical models that relate preconsolidation pressure (σp) to mechanical resistance to penetration (PR) and gravimetric soil water content (U) is important for defining strategies to prevent compaction of agricultural soils. Our objective was therefore to model the σp and compression index (CI) according to the PR (with an impact penetrometer in the field and a static penetrometer inserted at a constant rate in the laboratory) and U in a Rhodic Eutrudox. The experiment consisted of six treatments: no-tillage system (NT); NT with chiseling; and NT with additional compaction by combine traffic (passing 4, 8, 10, and 20 times). Soil bulk density, total porosity, PR (in field and laboratory measurements), U, σp, and CI values were determined in the 5.5-10.5 cm and 13.5-18.5 cm layers. Preconsolidation pressure (σp) and CI were modeled according to PR in different U. The σp increased and the CI decreased linearly with increases in the PR values. The correlations between σp and PR and PR and CI are influenced by U. From these correlations, the soil load-bearing capacity and compaction susceptibility can be estimated by PR readings evaluated in different U.
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ABSTRACT The expansion of the sugarcane industry in Brazil has intensified the mechanization of agriculture and caused effects on the soil physical quality. The purpose of this study was to evaluate the limiting water range and soil bearing capacity of a Latossolo Vermelho distroférrico típico (Rhodic Hapludox) under the influence of different tractor-trailers used in mechanical sugarcane harvesting. The experiment was arranged in a randomized block design with five replications. The treatments consisted of green sugarcane harvesting with: harvester without trailer (T1); harvester with two trailers with a capacity of 10 Mg each (T2); harvester with trailer with a capacity of 20 Mg (T3) and harvester and truck with trailer with a capacity of 20 Mg (10 Mg per compartment) (T4). The least limiting water range and soil bearing capacity were evaluated. The transport equipment to remove the harvested sugarcane from the field (trailer) at harvest decreased the least limiting water range, reducing the structural soil quality. The truck trailer caused the greatest impact on the soil physical properties studied. The soil load bearing capacity was unaffected by the treatments, since the pressure of the harvester (T1) exceeded the pre-consolidation pressure of the soil.