990 resultados para 230Th sup unc


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Glucose-dependent insulinotropic polypeptide (gastric inhibitory polypeptide [GIP]) is an important incretin hormone secreted by endocrine K-cells in response to nutrient ingestion. In this study, we investigated the effects of chemical ablation of GIP receptor (GIP-R) action on aspects of obesity-related diabetes using a stable and specific GIP-R antagonist, (Pro3)GIP. Young adult ob/ob mice received once-daily intraperitoneal injections of saline vehicle or (Pro3)GIP over an 11-day period. Nonfasting plasma glucose levels and the overall glycemic excursion (area under the curve) to a glucose load were significantly reduced (1.6-fold; P <0.05) in (Pro3)GIP-treated mice compared with controls. GIP-R ablation also significantly lowered overall plasma glucose (1.4-fold; P <0.05) and insulin (1.5-fold; P <0.05) responses to feeding. These changes were associated with significantly enhanced (1.6-fold; P <0.05) insulin sensitivity in the (Pro3)GIP-treated group. Daily injection of (Pro3)GIP reduced pancreatic insulin content (1.3-fold; P <0.05) and partially corrected the obesity-related islet hypertrophy and ß-cell hyperplasia of ob/ob mice. These comprehensive beneficial effects of (Pro3)GIP were reversed 9 days after cessation of treatment and were independent of food intake and body weight, which were unchanged. These studies highlight a role for GIP in obesity-related glucose intolerance and emphasize the potential of specific GIP-R antagonists as a new class of drugs for the alleviation of insulin resistance and treatment of type 2 diabetes.

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Background: DNA ligases catalyse phosphodiester bond formation between adjacent bases in nicked DNA, thereby sealing the nick. A key step in the catalytic mechanism is the formation of an adenylated DNA intermediate. The adenyl group is derived from either ATP (in eucaryotes and archaea) or NAD+4 (in bacteria). This difference in cofactor specificity suggests that DNA ligase may be a useful antibiotic target.

Results: The crystal structure of the adenylation domain of the NAD+-dependent DNA ligase from Bacillus stearothermophilus has been determined at 2.8 Å resolution. Despite a complete lack of detectable sequence similarity, the fold of the central core of this domain shares homology with the equivalent region of ATP-dependent DNA ligases, providing strong evidence for the location of the NAD+-binding site.

Conclusions: Comparison of the structure of the NAD+4-dependent DNA ligase with that of ATP-dependent ligases and mRNA-capping enzymes demonstrates the manifold utilisation of a conserved nucleotidyltransferase domain within this family of enzymes. Whilst this conserved core domain retains a common mode of nucleotide binding and activation, it is the additional domains at the N terminus and/or the C terminus that provide the alternative specificities and functionalities in the different members of this enzyme superfamily.

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Isotope shifts in dielectronic recombination spectra were studied for Li-like <sup style="margin: 0px; padding: 0px; border: 0px; font-size: 0.88em; vertical-align: 0.5em; line-height: 1em; color: rgb(50, 50, 50); font-family: arial, helvetica, sans-serif; text-align: justify; background-color: rgb(255, 255, 255);">Asup>Nd<sup style="margin: 0px; padding: 0px; border: 0px; font-size: 0.88em; vertical-align: 0.5em; line-height: 1em; color: rgb(50, 50, 50); font-family: arial, helvetica, sans-serif; text-align: justify; background-color: rgb(255, 255, 255);">57+sup> ions with A=142 and A=150. From the displacement of resonance positions energy shifts dE<sup style="margin: 0px; padding: 0px; border: 0px; font-size: 0.88em; vertical-align: 0.5em; line-height: 1em; color: rgb(50, 50, 50); font-family: arial, helvetica, sans-serif; text-align: justify; background-color: rgb(255, 255, 255);">142?150sup>(2s-2p1/2)=40.2(3)(6)??meV [(stat)(sys)] and dE<sup style="margin: 0px; padding: 0px; border: 0px; font-size: 0.88em; vertical-align: 0.5em; line-height: 1em; color: rgb(50, 50, 50); font-family: arial, helvetica, sans-serif; text-align: justify; background-color: rgb(255, 255, 255);">142?150sup>(2s-2p3/2)=42.3(12)(20)??meV of 2s-2pjtransitions were deduced. An evaluation of these values within a full QED treatment yields a change in the mean-square charge radius of <sup style="margin: 0px; padding: 0px; border: 0px; font-size: 0.88em; vertical-align: 0.5em; line-height: 1em; color: rgb(50, 50, 50); font-family: arial, helvetica, sans-serif; text-align: justify; background-color: rgb(255, 255, 255);">142?150sup>d?r<sup style="margin: 0px; padding: 0px; border: 0px; font-size: 0.88em; vertical-align: 0.5em; line-height: 1em; color: rgb(50, 50, 50); font-family: arial, helvetica, sans-serif; text-align: justify; background-color: rgb(255, 255, 255);">2sup>?=-1.36(1)(3)??fm<sup style="margin: 0px; padding: 0px; border: 0px; font-size: 0.88em; vertical-align: 0.5em; line-height: 1em; color: rgb(50, 50, 50); font-family: arial, helvetica, sans-serif; text-align: justify; background-color: rgb(255, 255, 255);">2sup>. The approach is conceptually new and combines the advantage of a simple atomic structure with high sensitivity to nuclear size.

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Objective: To evaluate the psychometric performance of the Child Health Questionnaire (CHQ) in children with cerebral palsy (CP).
Method: 818 parents of children with CP, aged 8–12 from nine regions of Europe completed the CHQ (parent form 50 items). Functional abilities were classified using the five-level Gross Motor Function Classification Scheme (Levels I–III as ambulant; Level IV–V as nonambulant CP).
Results: Ceiling effects were observed for a number of subscales and summary scores across all Gross Motor Function Classification System levels, whilst floor effects occurred only in the physical functioning scale (Level V CP). Reliability was satisfactory overall. Confirmatory factor analysis (CFA) revealed a seven-factor structure for the total sample of children with CP but with different factor structures for ambulant and nonambulant children.
Conclusion: The CHQ has limited applicability in children with CP, although with judicious use of certain domains for ambulant and nonambulant children can provide useful and comparable data about child health status for descriptive purposes.

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Tachykinins are among the most widely-studied families of regulatory peptides characterized by a highly-conserved C-terminal -Phe-X-Gly-Leu-Met.amide motif, which also constitutes the essential bioactive core. The amphibian skin has proved to be a rich source of these peptides with physalaemin from the skin of Physalaemus fuscomaculatus representing the archetypal aromatic tachykinin (X = Tyr or Phe) and kassinin from the skin of Kassina senegalensis representing the archetypal aliphatic tachykinin in which X = Val or Ile. Despite the primary structures of both mature peptides having been known for at least 30 years, neither the structures nor organizations of their biosynthetic precursors have been reported. Here we report the structure and organization of the biosynthetic precursor of kassinin deduced from cDNA cloned from a skin secretion library. In addition, a second precursor cDNA encoding the novel kassinin analog (Thr2, Ile9)-kassinin was identified as was the predicted mature peptide in skin secretion. Both transcripts exhibited a high degree of nucleotide sequence similarity and of open-reading frame translated amino acid sequences of putative precursor proteins. The translated preprotachykinins each consisted of 80 amino acid residues encoding single copies of either kassinin or its site-substituted analog. Synthetic replicates of each kassinin were found to be active on rat urinary bladder smooth muscle at nanomolar concentrations. The structural organization of both preprotachykinins differs from that previously reported for those of Odorrana grahami skin indicating a spectrum of diversity akin to that established for amphibian skin preprobradykinins.

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Published ab-initio and pseudopotential calculations for the dialkali halide systems suggest that the preferred co-linear geometry is for the metal to approach the metal end of the alkali halide. Here, ab-initio calculations on the Li2F system reveal that the well depth on the halide side in this radical is much deeper and is a local saddle-point associated with the ionic non-linear global minima. Although many features of the pseudopotential surfaces are confirmed, significant differences are apparent including the existence of a linear excited state instead of a triangular one, a considerably deeper global minimum some 50% lower in energy and a close approach between the X2A1 and the states, with the minimum 87 kJ mol-1 below the ground state asymptote. All the results can be rationalised as the avoided crossings between a long range, covalent potential dominant within the LiLiF geometry and an ionic state that forms the global minimum. Calculations on the 3rd 2A' potential indicate that even for Li + LiF collisions at ultracold temperatures the collision dynamics could involve as many as three electronic states.

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The ultrashort duration of laser-driven multi-MeV ion bursts offers the possibility of radiobiological studies at extremely high dose rates. Employing the TARANIS Terawatt laser at Queen's University, the effect of proton irradiation at MeV-range energies on live cells has been investigated at dose rates exceeding 109 Gy/s as a single exposure. A clonogenic assay showed consistent lethal effects on V-79 live cells, which, even at these dose rates, appear to be in line with previously published results employing conventional sources. A Relative Biological Effectiveness (RBE) of 1.4±0.2 at 10% survival is estimated from a comparison with a 225 kVp X-ray source.

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Fasciolosis is a parasitic infection by the liver fluke Fasciola hepatica, which costs the global agricultural community over US $2 billion per year. Its prevalence is rising due to factors such as climate change and drug resistance. ATP-dependent membrane transporters are considered good potential drug targets as they are essential for cellular processes and are in an exposed, accessible position in the cell. Immunolocalisation studies demonstrated that a plasma membrane calcium ATPase (PMCA) was localised to the parenchymal tissue in F. hepatica. The coding sequence for a F. hepatica PMCA (FhPMCA) has been obtained. This sequence encodes a 1,163 amino acid protein which contains motifs which are commonly conserved in PMCAs. Molecular modelling predicted that the protein has 10 transmembrane segments which include a potential calcium ion binding site and phosphorylation motif. FhPMCA interacts with the calmodulin-like protein FhCaM1, but not the related proteins FhCaM2 or FhCaM3, in a calcium-ion dependent manner. This interaction occurs through a region in the C-terminal region of FhPMCA which most likely adopts an a-helical conformation. When FhPMCA was heterologously expressed in a budding yeast strain deleted for its PMCA (Pmc1p), it restored viability. Microsomes prepared from these yeast cells had calcium ion stimulated ATPase activity which was inhibited by the known PMCA inhibitors, bisphenol and eosin. The potential of FhPMCA as a new drug target is discussed.

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Allergic contact dermatitis is the most frequent occupational disease in industrialized countries. It is caused by CD8(+) T cell-mediated contact hypersensitivity (CHS) reactions triggered at the site of contact by a variety of chemicals, also known as weak haptens, present in fragrances, dyes, metals, preservatives, and drugs. Despite the myriad of potentially allergenic substances that can penetrate the skin, sensitization is relatively rare and immune tolerance to the substance is often induced by as yet poorly understood mechanisms. Here we show, using the innocuous chemical 2,4-dinitrothiocyanobenzene (DNTB), that cutaneous immune tolerance in mice critically depends on epidermal Langerhans cells (LCs), which capture DNTB and migrate to lymph nodes for direct presentation to CD8(+) T cells. Depletion and adoptive transfer experiments revealed that LCs conferred protection from development of CHS by a mechanism involving both anergy and deletion of allergen-specific CD8(+) T cells and activation of a population of T cells identified as ICOS(+)CD4(+)Foxp3(+) Tregs. Our findings highlight the critical role of LCs in tolerance induction in mice to the prototype innocuous hapten DNTB and suggest that strategies targeting LCs might be valuable for prevention of cutaneous allergy.

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The concept of space entered architectural history as late as 1893. Studies in art opened up the discussion, and it has been studied in various ways in architecture ever since. This article aims to instigate an additional reading to architectural history, one that is not supported by "isms" but based on space theories in the 20th century. Objectives of the article are to bring the concept of space and its changing paradigms to the attention of architectural researchers, to introduce a conceptual framework to classify and clarify theories of space, and to enrich the discussions on the 20th century architecture through theories that are beyond styles. The introduction of space in architecture will revolve around subject-object relationships, three-dimensionality and senses. Modern space will be discussed through concepts such as empathy, perception, abstraction, and geometry. A scientific approach will follow to study the concept of place through environment, event, behavior, and design methods. Finally, the research will look at contemporary approaches related to digitally supported space via concepts like reality-virtuality, mediated experience, and relationship with machines.

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RATIONALE Stable isotope values (d<sup>13sup>C and d<sup>15sup>N) of darted skin and blubber biopsies can shed light on habitat use and diet of cetaceans, which are otherwise difficult to study. Non-dietary factors affect isotopic variability, chiefly the depletion of C due to the presence of C-rich lipids. The efficacy of post hoc lipid-correction models (normalization) must be tested. METHODS For tissues with high natural lipid content (e.g., whale skin and blubber), chemical lipid extraction or normalization is necessary. C:N ratios, d<sup>13sup>C values and d<sup>15sup>N values were determined for duplicate control and lipid-extracted skin and blubber of fin (Balaenoptera physalus), humpback (Megaptera novaeangliae) and minke whales (B. acutorostrata) by continuous-flow elemental analysis isotope ratio mass spectrometry (CF-EA-IRMS). Six different normalization models were tested to correct d<sup>13sup>C values for the presence of lipids. RESULTS Following lipid extraction, significant increases in d<sup>13sup>C values were observed for both tissues in the three species. Significant increases were also found for d<sup>15sup>N values in minke whale skin and fin whale blubber. In fin whale skin, the d<sup>15sup>N values decreased, with no change observed in humpback whale skin. Non-linear models generally out-performed linear models and the suitability of models varied by species and tissue, indicating the need for high model specificity, even among these closely related taxa. CONCLUSIONS Given the poor predictive power of the models to estimate lipid-free d13C values, and the unpredictable changes in d N values due to lipid-extraction, we recommend against arithmetical normalization in accounting for lipid effects on d13C values for balaenopterid skin or blubber samples. Rather, we recommend that duplicate analysis of lipid-extracted (d13C values) and non-treated tissues (d15N values) be used. Copyright © 2012 John Wiley & Sons, Ltd.