423 research outputs found

    Aluminium-oxide wires for superconducting high kinetic inductance circuits

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    We investigate thin films of conducting aluminium-oxide, also known as granular aluminium, as a material for superconducting high quality, high kinetic inductance circuits. The films are deposited by an optimised reactive DC magnetron sputter process and characterised using microwave measurement techniques at milli-Kelvin temperatures. We show that, by precise control of the reactive sputter conditions, a high room temperature sheet resistance and therefore high kinetic inductance at low temperatures can be obtained. For a coplanar waveguide resonator with 1.5\,kΩ\Omega sheet resistance and a kinetic inductance fraction close to unity, we measure a quality factor in the order of 700\,000 at 20\,mK. Furthermore, we observe a sheet resistance reduction by gentle heat treatment in air. This behaviour is exploited to study the kinetic inductance change using the microwave response of a coplanar wave guide resonator. We find the correlation between the kinetic inductance and the sheet resistance to be in good agreement with theoretical expectations.Comment: 16 pages, 7 figure

    Interplay of magnetization dynamics with a microwave waveguide at cryogenic temperatures

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    In this work, magnetization dynamics is studied at low temperatures in a hybrid system that consists of a thin epitaxial magnetic film coupled with a superconducting planar microwave waveguide. The resonance spectrum was observed over a wide magnetic field range, including low fields below the saturation magnetization and both polarities. Analysis of the spectrum via a fitting routine we develop allows the derivation of all magnetic parameters of the film at cryogenic temperatures, the detection of waveguide-induced uniaxial magnetic anisotropies of the first and the second order, and the uncovering of a minor misalignment of the magnetic field. A substantial influence of the superconducting critical state on the resonance spectrum is observed and discussed

    Articular cartilage and labral lesions of the glenohumeral joint: diagnostic performance of 3D water-excitation true FISP MR arthrography

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    OBJECTIVE: To evaluate the diagnostic performance of MR arthrography in the detection of articular cartilage and labral lesions of the glenohumeral joint using a transverse 3D water-excitation true fast imaging with steady-state precession (FISP) sequence. MATERIALS AND METHODS: Seventy-five shoulders were included retrospectively. Shoulder arthroscopy was performed within 6 months of MR arthrography. MR images were evaluated separately by two radiologists. They were blinded to clinical and arthroscopic information. Arthroscopy served as the reference standard. RESULTS: For the detection of humeral cartilage lesions, sensitivities and specificities were 86% (12/14)/89% (50/56) for observer 1 and 93%/86% for observer 2) for the transverse true FISP sequence and 64%/86% (50%/82% for observer 2) for the coronal intermediate-weighted spin-echo images. The corresponding values for the glenoidal cartilage were 60% (6/10)/88% (51/58) (80%/76% for observer 2) and 70%/86% (60%/74% for observer 2) respectively. For the detection of abnormalities of the anterior labrum (only assessed on true FISP images) the values were 94% (15/16)/84% (36/43) (88%/79% for observer 2). The corresponding values for the posterior labrum were 67% (8/12)/77% (36/47) (observer 2: 25%/74%). The kappa values for the grading of the humeral and glenoidal cartilage lesions were 0.81 and 0.55 for true FISP images compared with 0.49 and 0.43 for intermediate-weighted fast spin-echo images. Kappa values for true FISP evaluation of the anterior and posterior part of the labrum were 0.81 and 0.70. CONCLUSION: Transverse 3D true FISP MR arthrography images are useful for the difficult diagnosis of glenohumeral cartilage lesions and suitable for detecting labral abnormalities

    Evaluation of range of motion restriction within the hip joint

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    In Total Hip Arthroplasty, determining the impingement free range of motion requirement is a complex task. This is because in the native hip, motion is restricted by both impingement as well as soft tissue restraint. The aim of this study is to determine a range of motion benchmark which can identify motions which are at risk from impingement and those which are constrained due to soft tissue. Two experimental methodologies were used to determine motions which were limited by impingement and those motions which were limited by both impingement and soft tissue restraint. By comparing these two experimental results, motions which were limited by impingement were able to be separated from those motions which were limited by soft tissue restraint. The results show motions in extension as well as flexion combined with adduction are limited by soft tissue restraint. Motions in flexion, flexion combined with abduction and adduction are at risk from osseous impingement. Consequently, these motions represent where the maximum likely damage will occur in femoroacetabular impingement or at most risk of prosthetic impingement in Total Hip Arthroplasty

    Does the Constitution Provide More Ballot Access Protection for Presidential Elections Than for U.S. House Elections?

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    Both the U.S. Constitution and The Federalist Papers suggest that voters ought to have more freedom to vote for the candidate of their choice for the U.S. House of Representatives than they do for the President or the U.S. Senate. Yet, strangely, for the last thirty-three years, the U.S. Supreme Court and lower courts have ruled that the Constitution gives voters more freedom to vote for the candidate of their choice in presidential elections than in congressional elections. Also, state legislatures, which have been writing ballot access laws since 1888, have passed laws that make it easier for minor-party and independent candidates to get on the ballot for President than for the U.S. House. As a result, voters in virtually every state invariably have far more choices on their general election ballots for the President than they do for the House. This Article argues that the right of a voter to vote for someone other than a Democrat or a Republican for the House is just as important as a voter’s right to do so for President, and that courts should grant more ballot access protection to minor-party and independent candidates for the House

    MRI classification of interspinous ligament degeneration of the lumbar spine: intraobserver and interobserver reliability and the frequency of disagreement

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    Posterior spinal ligament pathology is becoming increasingly recognized as a significant cause of low back pain. Despite the growing clinical importance of interspinous ligament degeneration in low back pain patients, formal reliability studies for the magnetic resonance imaging (MRI) evaluation of interspinous ligaments have not been performed. We proposed an MRI classification system for interspinous ligament degeneration and conducted a comprehensive reliability and reproducibility assessment. Fifty patients who had low back pain with or without leg discomfort (26 males and 24 females) with a mean age of 48.8 years (range 23–85 years) were studied. The classification for lumbar interspinous ligament degeneration was developed on the basis of the literature using mid-sagittal T1- and T2-weighted images. Three spine surgeons independently graded a total of 200 interspinous ligament levels. Intraobserver and interobserver reliability were assessed by kappa statistics. The frequency of disagreement was also identified. The intraobserver agreement was excellent in all readers (kappa range 0.840–0.901). The interobserver agreement was lower as expected, and was substantial to excellent (kappa range 0.726–0.818). Overall complete agreement was obtained in 87.8% of all interspinous ligament levels. A difference of 1, 2, and 3 grades occurred in 8.1, 3.0, and 1.1% of readings, respectively. This proposed MRI classification of interspinous ligament degeneration was simple, reliable, and reproducible. Its use as a standardized nomenclature in clinical and radiographic research may be recommended

    Comparative reliability and diagnostic performance of conventional 3T magnetic resonance imaging and 1.5T magnetic resonance arthrography for the evaluation of internal derangement of the hip

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    Objective; To compare the diagnostic accuracy of conventional 3T MRI against 1.5T MR arthrography (MRA) in patients with clinical femoroacetabular impingement (FAI). Methods; Sixty-eight consecutive patients with clinical FAI underwent both 1.5T MRA and 3T MRI. Imaging was prospectively analysed by two musculoskeletal radiologists, blinded to patient outcomes and scored for internal derangement including labral and cartilage abnormality. Interobserver variation was assessed by kappa analysis. Thirty-nine patients subsequently underwent hip arthroscopy and surgical results and radiology findings were analysed. Results; Both readers had higher sensitivities for detecting labral tears with 3T MRI compared to 1.5T MRA (not statistically significant p=0.07). For acetabular cartilage defect both readers had higher statistically significant sensitivities using 3T MRI compared to 1.5T MRA (p=0.02). Both readers had a slightly higher sensitivity for detecting delamination with 1.5T MRA compared to 3T MRI, but these differences were not statistically significant (p=0.66). Interobserver agreement was substantial to perfect agreement for all parameters except the identification of delamination (3T MRI showed moderate agreement and 1.5T MRA substantial agreement). Conclusion; Conventional 3T MRI may be at least equivalent to 1.5T MRA in detecting acetabular labrum and possibly superior to 1.5T MRA in detecting cartilage defects in patients with suspected FAI

    PRC2 loss induces chemoresistance by repressing apoptosis in T cell acute lymphoblastic leukemia

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    The tendency of mitochondria to undergo or resist BCL2-controlled apoptosis (so-called mitochondrial priming) is a powerful predictor of response to cytotoxic chemotherapy. Fully exploiting this finding will require unraveling the molecular genetics underlying phenotypic variability in mitochondrial priming. Here, we report that mitochondria) apoptosis resistance in T cell acute lymphoblastic leukemia (T-ALL) is mediated by inactivation of polycomb repressive complex 2 (PRC2). In T-ALL clinical specimens, loss-of-function mutations of PRC2 core components (EZH2, FED, or SUZ12) were associated with mitochondrial apoptosis resistance. In T-ALL cells, PRC2 depletion induced resistance to apoptosis induction by multiple chemotherapeutics with distinct mechanisms of action. PRC2 loss induced apoptosis resistance via transcriptional up-regulation of the LIM domain transcription factor CRIP2 and downstream up-regulation of the mitochondrial chaperone TRAP1. These findings demonstrate the importance of mitochondrial apoptotic priming as a prognostic factor in T-ALL and implicate mitochondrial chaperone function as a molecular determinant of chemotherapy response

    Ulnar-sided wrist pain. Part I: anatomy and physical examination

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    Ulnar-sided wrist pain is a common complaint, and it presents a diagnostic challenge for hand surgeons and radiologists. The complex anatomy of this region, combined with the small size of structures and subtle imaging findings, compound this problem. A thorough understanding of ulnar-sided wrist anatomy and a systematic clinical examination of this region are essential in arriving at an accurate diagnosis. In part I of this review, ulnar-sided wrist anatomy and clinical examination are discussed for a more comprehensive understanding of ulnar-sided wrist pain
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