1,336 research outputs found

    T cell specific adaptor protein (TSAd) promotes interaction of Nck with Lck and SLP-76 in T cells

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    Background: The Lck and Src binding adaptor protein TSAd (T cell specific adaptor) regulates actin polymerization in T cells and endothelial cells. The molecular details as to how TSAd regulates this process remain to be elucidated. Results: To identify novel interaction partners for TSAd, we used a scoring matrix-assisted ligand algorithm (SMALI), and found that the Src homology 2 (SH2) domain of the actin regulator Non-catalytic region of tyrosine kinase adaptor protein (Nck) potentially binds to TSAd phosphorylated on Tyr280 (pTyr280) and pTyr305. These predictions were confirmed by peptide array analysis, showing direct binding of recombinant Nck SH2 to both pTyr280 and pTyr305 on TSAd. In addition, the SH3 domains of Nck interacted with the proline rich region (PRR) of TSAd. Pull-down and immunoprecipitation experiments further confirmed the Nck-TSAd interactions through Nck SH2 and SH3 domains. In line with this Nck and TSAd co-localized in Jurkat cells as assessed by confocal microscopy and imaging flow cytometry. Co-immunoprecipitation experiments in Jurkat TAg cells lacking TSAd revealed that TSAd promotes interaction of Nck with Lck and SLP-76, but not Vav1. TSAd expressing Jurkat cells contained more polymerized actin, an effect dependent on TSAd exon 7, which includes interactions sites for both Nck and Lck. Conclusions: TSAd binds to and co-localizes with Nck. Expression of TSAd increases both Nck-Lck and Nck-SLP-76 interaction in T cells. Recruitment of Lck and SLP-76 to Nck by TSAd could be one mechanism by which TSAd promotes actin polymerization in activated T cells. © 2015 Hem et al

    Pauli Paramagnetic Effects on Vortices in Superconducting TmNi2B2C

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    The magnetic field distribution around the vortices in TmNi2B2C in the paramagnetic phase was studied experimentally as well as theoretically. The vortex form factor, measured by small-angle neutron scattering, is found to be field independent up to 0.6 Hc2 followed by a sharp decrease at higher fields. The data are fitted well by solutions to the Eilenberger equations when paramagnetic effects due to the exchange interaction with the localized 4f Tm moments are included. The induced paramagnetic moments around the vortex cores act to maintain the field contrast probed by the form factor.Comment: 4 pages, 4 figure

    Temperature Dependence of the Flux Line Lattice Transition into Square Symmetry in Superconducting LuNi2_2B2_2C

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    We have investigated the temperature dependence of the H || c flux line lattice structural phase transition from square to hexagonal symmetry, in the tetragonal superconductor LuNi_2B_2C (T_c = 16.6 K). At temperatures below 10 K the transition onset field, H_2(T), is only weakly temperature dependent. Above 10 K, H_2(T) rises sharply, bending away from the upper critical field. This contradicts theoretical predictions of H_2(T) merging with the upper critical field, and suggests that just below the H_c2(T)-curve the flux line lattice might be hexagonal.Comment: 4 pages, 3 figure

    Fermi surface and order parameter driven vortex lattice structure transitions in twin-free YBa2Cu3O7

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    We report on small-angle neutron scattering studies of the intrinsic vortex lattice (VL) structure in detwinned YBa2Cu3O7 at 2 K, and in fields up to 10.8 T. Because of the suppressed pinning to twin-domain boundaries, a new distorted hexagonal VL structure phase is stabilized at intermediate fields. It is separated from a low-field hexagonal phase of different orientation and distortion by a first-order transition at 2.0(2) T that is probably driven by Fermi surface effects. We argue that another first-order transition at 6.7(2) T, into a rhombic structure with a distortion of opposite sign, marks a crossover from a regime where Fermi surface anisotropy is dominant, to one where the VL structure and distortion is controlled by the order-parameter anisotropy.Comment: 4 pages, 3 figures (2 color), minor change

    Patient level pooled analysis of 68,500 patients from seven major vitamin D fracture trials in the US and Europe

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    Objectives To identify participants’ characteristics that influence the anti-fracture efficacy of vitamin D or vitamin D plus calcium with respect to any fracture, hip fracture, and clinical vertebral fracture and to assess the influence of dosing regimens and co-administration of calcium. Design Individual patient data analysis using pooled data from randomised trials. Data sources Seven major randomised trials of vitamin D with calcium or vitamin D alone, yielding a total of 68 517 participants (mean age 69.9 years, range 47-107 years, 14.7% men). Study selection Studies included were randomised studies with at least one intervention arm in which vitamin D was given, fracture as an outcome, and at least 1000 participants. Data synthesis Logistic regression analysis was used to identify significant interaction terms, followed by Cox’s proportional hazards models incorporating age, sex, fracture history, and hormone therapy and bisphosphonate use. Results Trials using vitamin D with calcium showed a reduced overall risk of fracture (hazard ratio 0.92, 95% confidence interval 0.86 to 0.99, P=0.025) and hip fracture (all studies: 0.84, 0.70 to 1.01, P=0.07; studies using 10 μg of vitamin D given with calcium: 0.74, 0.60 to 0.91, P=0.005). For vitamin D alone in daily doses of 10 μg or 20 μg, no significant effects were found. No interaction was found between fracture history and treatment response, nor any interaction with age, sex, or hormone replacement therapy. Conclusion This individual patient data analysis indicates that vitamin D given alone in doses of 10-20 μg is not effective in preventing fractures. By contrast, calcium and vitamin D given together reduce hip fractures and total fractures, and probably vertebral fractures, irrespective of age, sex, or previous fractures.The WHI program is funded by the National Heart, Lung, and Blood Institute, National Institutes of Health, US Department of Health and Human Services through contracts N01WH22110, 24152, 32100-2, 32105-6, 32108-9, 32111-13, 32115, 32118-32119, 32122, 42107-26, 42129-32, and 44221. AA acknowledges personal funding from the UK Medical Research Council and Chief Scientist Office of the Scottish Government Health Directorates

    Low Levels of Hemoglobin at Admission Are Associated With Increased 30-Day Mortality in Patients With Hip Fracture

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    INTRODUCTION: Previous smaller studies suggest that anemia is a risk factor for mortality in patients with hip fracture. The purpose of this investigation was to assess the correlation between hemoglobin at admission with 30-day mortality following a hip fracture in a large-scale study. PATIENTS AND METHODS: From January 1996 to December 2012, all patients with hip fracture (>60 years of age) admitted to Bispebjerg Hospital, Copenhagen, were identified from a local hip fracture database. We excluded conservatively treated patients and patients who died preoperatively. RESULTS: Seven thousand four hundred twenty-one consecutive patients with hip fracture were identified. Of those 7319 had a hemoglobin measurement on admission and were thus eligible for further analysis. Mean hemoglobin for patients alive at 30 days was 7.6 (standard deviation [SD]: 1.0) and for deceased patients 7.4 (SD: 1.1), P < .0001. Mean age was 82.6 years (SD: 8.5), and 76.5% of the population were female (N(females) = 5600). The 30-day mortality decreases for every increase in hemoglobin of 1.0 mmol/L in a univariate analysis (P < .0001). The hazard ratio (HR) with 95% confidence interval (CI) for 30-day mortality in patients with anemia (<7.3 mmol/L for females and <8.3 mmol/L for males; N(anemic) = 3235) was 1.66 (CI: 1.43-1.91, P < .0001). Adjusting for age, type of fracture, gender, and comorbidities (Charlson score) slightly attenuated the risk estimate (HR: 1.21, CI: 1.03-1.41, P = .02). CONCLUSION: This study demonstrates increased 30-day mortality in patients with low hemoglobin at admission, even after adjusting for comorbidities

    The Amundsen Sea Polynya International Research Expedition (ASPIRE)

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    In search of an explanation for some of the greenest waters ever seen in coastal Antarctica and their possible link to some of the fastest melting glaciers and declining summer sea ice, the Amundsen Sea Polynya International Research Expedition (ASPIRE) challenged the capabilities of the US Antarctic Program and RVIB Nathaniel B. Palmer during Austral summer 2010–2011. We were well rewarded by both an extraordinary research platform and a truly remarkable oceanic setting. Here we provide further insights into the key questions that motivated our sampling approach during ASPIRE and present some preliminary findings, while highlighting the value of the Palmer for accomplishing complex, multifaceted oceanographic research in such a challenging environment

    Organic flow assurance: Asphaltene dispersant/inhibitor formulation development through experimental design

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    Master's thesis in Environmental TechnologyThe exploitation of hydrocarbon has forced the petroleum production to move closer to extreme climate areas and deep waters such as the Barents Sea. These challenges require effective and safe production, transport and processing of the petroleum sources. Chemical and physical changes in the reservoir may cause different types of unpredicted problems such as organic deposits which are mainly asphaltene and wax precipitation. Wax precipitation is very common in subsea pipelines. Asphaltenes are more affected by for example pressure drops and high shear, which may cause formation damage as well as plugup the well-bores and tubing. In the petroleum industry, flow assurance has become a key concern where the cold sea bottom temperatures and extreme water depths give rise to enormous technical challenges which includes the management of solids such as asphaltenes and wax. Flow assurance is defined as “safe, uninterrupted and simultaneous transport of gas, oil and water from reservoirs to processing facilities”. The term refers to the need to guarantee flow of oil and gas from the reservoirs to the processing facilities. In this thesis the focus will be on chemical control of asphaltene and the formulation of an optimal asphaltene dispersant mixture. An experimental method needed to be established for the screening tests of the dispersant mixtures. When performing a screening test, the experimental method is desired to be simple and quick. This will save time and money as the screening test will only give an idea of how the system works and interacts. Different methods were tested such as measurement of the asphaltene deposit level, spot test, UV-Vis spectroscopy and turbidity measurements. Turbidity measurement was decided to be used in the formulation of an optimal asphaltene dispersant mixture. Design of experiments (DoE) and mixture design are well known methods which are often used when mixing together multiple components. DoE techniques provide an idea of how the mixtures work together and can then optimize the formulation at a minimum effort and cost. The computer software, Design Expert was used for the experimental design in this thesis. The program was used to set up an experimental plan which showed the mixture components and the mixture proportions to be tested. When the results were ready, they were inserted in Design Expert and a model was suggested. The analysis of the model was also done by Design Expert which made it possible to easily detect certain trends in the model such as identifying results that deviated from the model in form of failed experiments. Three different crude oils were tested, Crudo-Metapetroleum a viscous and heavy crude oil with an asphaltene content of 12,1535g/100ml, Hier D02A crude oil which is a more common crude oil with an asphaltene content of 2,2380g/100ml and Jordbær crude oil with an asphaltene content of 0,2210g/100ml. Three commercial asphaltene dispersant were tested in order to find an optimal mixture formulation. The dispersants used for these tests, dodecyl benzene sulfonic acid (DDBSA), Hybase M-401 and Flowsolve 113, did not show any usable synergistic effects. The results showed that the best dispersant was Flowsolve 113

    Distinct subsets of unmyelinated primary sensory fibers mediate behavioral responses to noxious thermal and mechanical stimuli

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    Behavioral responses to painful stimuli require peripheral sensory neurons called nociceptors. Electrophysiological studies show that most C-fiber nociceptors are polymodal (i.e., respond to multiple noxious stimulus modalities, such as mechanical and thermal); nevertheless, these stimuli are perceived as distinct. Therefore, it is believed that discrimination among these modalities only occurs at spinal or supraspinal levels of processing. Here, we provide evidence to the contrary. Genetic ablation in adulthood of unmyelinated sensory neurons expressing the G protein-coupled receptor Mrgprd reduces behavioral sensitivity to noxious mechanical stimuli but not to heat or cold stimuli. Conversely, pharmacological ablation of the central branches of TRPV1+ nociceptors, which constitute a nonoverlapping population, selectively abolishes noxious heat pain sensitivity. Combined elimination of both populations yielded an additive phenotype with no additional behavioral deficits, ruling out a redundant contribution of these populations to heat and mechanical pain sensitivity. This double-dissociation suggests that the brain can distinguish different noxious stimulus modalities from the earliest stages of sensory processing

    Women's experiences of their osteoporosis diagnosis at the time of diagnosis and 6 months later: A phenomenological hermeneutic study

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    This paper describes a phenomenological hermeneutic study of experiences of women who were recently diagnosed with osteoporosis. The research objective was to investigate women's experiences of living with osteoporosis during the first 6 months after diagnosis when treatment was first prescribed. Fifteen women were included in the study. The inclusion criteria were a DXA scan at one of the two hospitals showing a T-score below −2.5 (lower back or hip), age 65 years or older; no previous known osteoporotic fracture; at least one of the known risk factors for osteoporosis; and prescription of anti-osteoporotic treatment. Exclusion criteria were previous diagnosis of osteoporosis or previous treatment with anti-osteoporotic medication. Data were collected through in-depth interviews shortly after diagnosis and 6 months later. The performed analyses were inspired by Paul Ricoeur's theory of interpretation of texts comprising three levels: naïve reading, structural analysis, and critical interpretation and discussion. Three key themes emerged: 1) being diagnosed, 2) being prescribed medical treatment, and 3) being on the path of learning to live with osteoporosis. The findings suggest a need for improved support for the patients to gain understanding of their diagnosis and the risk of osteoporotic fracture as well as to learn to live with osteoporosis. The study highlights new health promotion areas for targeting interventions at newly diagnosed patients, helping them accept and interpret the diagnosis, and the medical treatment
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