77 research outputs found

    Concentration Dependence of Superconductivity and Order-Disorder Transition in the Hexagonal Rubidium Tungsten Bronze RbxWO3. Interfacial and bulk properties

    Full text link
    We revisited the problem of the stability of the superconducting state in RbxWO3 and identified the main causes of the contradictory data previously published. We have shown that the ordering of the Rb vacancies in the nonstoichiometric compounds have a major detrimental effect on the superconducting temperature Tc.The order-disorder transition is first order only near x = 0.25, where it cannot be quenched effectively and Tc is reduced below 1K. We found that the high Tc's which were sometimes deduced from resistivity measurements, and attributed to compounds with .25 < x < .30, are to be ascribed to interfacial superconductivity which generates spectacular non-linear effects. We also clarified the effect of acid etching and set more precisely the low-rubidium-content boundary of the hexagonal phase.This work makes clear that Tc would increase continuously (from 2 K to 5.5 K) as we approach this boundary (x = 0.20), if no ordering would take place - as its is approximately the case in CsxWO3. This behaviour is reminiscent of the tetragonal tungsten bronze NaxWO3 and asks the same question : what mechanism is responsible for this large increase of Tc despite the considerable associated reduction of the electron density of state ? By reviewing the other available data on these bronzes we conclude that the theoretical models which are able to answer this question are probably those where the instability of the lattice plays a major role and, particularly, the model which call upon local structural excitations (LSE), associated with the missing alkali atoms.Comment: To be published in Physical Review

    Cardiovascular Magnetic Resonance Reference Ranges From the Healthy Hearts Consortium

    Get PDF
    Background: The absence of population-stratified cardiovascular magnetic resonance (CMR) reference ranges from large cohorts is a major shortcoming for clinical care. Objectives: This paper provides age-, sex-, and ethnicity-specific CMR reference ranges for atrial and ventricular metrics from the Healthy Hearts Consortium, an international collaborative comprising 9,088 CMR studies from verified healthy individuals, covering the complete adult age spectrum across both sexes, and with the highest ethnic diversity reported to date. Methods: CMR studies were analyzed using certified software with batch processing capability (cvi42, version 5.14 prototype, Circle Cardiovascular Imaging) by 2 expert readers. Three segmentation methods (smooth, papillary, anatomic) were used to contour the endocardial and epicardial borders of the ventricles and atria from long- and short-axis cine series. Clinically established ventricular and atrial metrics were extracted and stratified by age, sex, and ethnicity. Variations by segmentation method, scanner vendor, and magnet strength were examined. Reference ranges are reported as 95% prediction intervals. Results: The sample included 4,452 (49.0%) men and 4,636 (51.0%) women with average age of 61.1 ± 12.9 years (range: 18-83 years). Among these, 7,424 (81.7%) were from White, 510 (5.6%) South Asian, 478 (5.3%) mixed/other, 341 (3.7%) Black, and 335 (3.7%) Chinese ethnicities. Images were acquired using 1.5-T (n = 8,779; 96.6%) and 3.0-T (n = 309; 3.4%) scanners from Siemens (n = 8,299; 91.3%), Philips (n = 498; 5.5%), and GE (n = 291, 3.2%). Conclusions: This work represents a resource with healthy CMR-derived volumetric reference ranges ready for clinical implementation

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

    Get PDF
    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Hipervitaminose D em animais

    Full text link
    Por meio de revisĂŁo da literatura, sĂŁo apresentados dados referentes ao metabolismo da vitamina D, bem como aos principais aspectos toxicolĂłgicos, clĂ­nicos, bioquĂ­micos, macroscĂłpicos, microscĂłpicos, ultraestruturais, imuno-histoquĂ­micos e radiogrĂĄficos de animais intoxicados natural e experimentalmente por essa vitamina, em diferentes espĂ©cies. Este estudo objetiva demonstrar a existĂȘncia de muitas lacunas no conhecimento sobre mineralização fisiolĂłgica e patolĂłgica, em especial na mediação hormonal do fenĂŽmeno, bem como alertar para os riscos de ocorrĂȘncia dessa intoxicação

    Kluwer sociale gids

    No full text

    Intra-operative Assessment of Axillary Sentinel Lymph Nodes by Frozen Section—An Observational Study of 260 Procedures

    No full text
    Sentinel lymph node biopsy (SLNB) has become the standard treatment for patients with invasive breast cancer. Intra-operative frozen section allows for the detection of nodal metastases, thereby allowing a simultaneous axillary lymph node dissection (ALND) for those patients with nodal metastases. We herein report the accuracy of frozen section in the detection of SLN metastases. Methods: Patients with operable breast cancer and clinically negative axillae were recruited for SLNB. The SLNs were identified by blue dye, an isotope, or a combination. Enlarged lymph nodes that were not SLNs were also excised. All nodes were examined by intra-operative frozen section. ALND was performed if frozen section was positive. For those without metastases on frozen section, ALND was not performed. All lymph nodes underwent further paraffin sectioning with immuno-histochemical staining. Results: A total of 260 SLNB procedures were performed for invasive carcinoma over a 3-year period. The SLN was identified in 93.5% of patients. Of the 243 successful procedures, 53 had nodal metastases on frozen section. A total of 33 patients had false-negative frozen sections (false-negative rate, 38.4%), and 97% of them were less than 2 mm in size. The false-negative rate for macro-metastases, micro-metastases, and isolated tumour cells_were 2.4%, 57.7%, and 94.4%, respectively (p < 0.0001). A total of 22 patients had delayed ALND, and the re-operation rate was 8.5%. Conclusion: Frozen section was useful for the detection of nodal metastases in the SLNs and allowed for ALND to be performed in the same operation. The main failure of frozen sections was in the detection of micro-metastases

    Laparoscopic Intragastric Approach for Stromal Tumours Located at the Posterior Gastric Wall

    Get PDF
    Surgical resection is indicated for gastrointestinal stromal tumour (GIST). Laparoscopic resection with clear margins is effective in gastric GIST. However, GIST located in the posterior gastric wall with close proximity to the oesophagogastric junction poses special challenges. Laparoscopic intragastric resection offers a new approach to the management of these tumours. The surgical technique, our experience and a summary of the literature are presented

    Spanning tree approaches for statistical sentence generation

    No full text
    In abstractive summarisation, summaries can include novel sentences that are generated automatically. In order to improve the grammaticality of the generated sentences, we model a global (sentence) level syntactic structure. We couch statistical sentence generation as a spanning tree problem in order to search for the best dependency tree spanning a set of chosen words. We also introduce a new search algorithm for this task that models argument satisfaction to improve the linguistic validity of the generated tree. We treat the allocation of modifiers to heads as a weighted bipartite graph matching problem (also known as the assignment problem), a well studied problem in graph theory. Using BLEU to measure performance on a string regeneration task, we demonstrate an improvement over standard language model baselines, illustrating the benefit of the spanning tree approach incorporating an argument satisfaction model.32 page(s
    • 

    corecore