Nanoscale Impurity Structures on the Surface of dx2−y2d_{x^2-y^2}-wave Superconductors

We study the effects of nanoscale impurity structures on the local electronic structure of $d_{x^2-y^2}$-wave superconductors. We show that the interplay between the momentum dependence of the superconducting gap, the geometry of the nanostructure and its orientation gives rise to a series of interesting quantum effects. Among these are the emergence of a zero bias conductance peak in the superconductor's density of states and the suppression of impurity states for certain nanostructures. The latter effect can be used to screen impurity resonances in the superconducting state.Comment: 4 pages, 5 figure

Quantum Interference between Impurities: Creating Novel Many-Body States in s-wave Superconductors

We demonstrate that quantum interference of electronic waves that are scattered by multiple magnetic impurities in an s-wave superconductor gives rise to novel bound states. We predict that by varying the inter-impurity distance or the relative angle between the impurity spins, the states' quantum numbers, as well as their distinct frequency and spatial dependencies, can be altered. Finally, we show that the superconductor can be driven through multiple local crossovers in which its spin polarization, $$, changes between $=0, 1/2$ and 1.Comment: 4 pages, 4 figure

Quantum interference between non-magnetic impurities in d_x2-y2-wave superconductors

We study quantum interference of electronic waves that are scattered by multiple non-magnetic impurities in a d_x2-y2-wave superconductor. We show that the number of resonance states in the density-of-states (DOS), as well as their frequency and spatial dependence change significantly as the distance between the impurities or their orientation relative to the crystal lattice is varied. Since the latter effect arises from the momentum dependence of the superconducting gap, we argue that quantum interference is a novel tool to identify the symmetry of unconventional superconductors.Comment: 4 pages, 4 figure

Multiple Soft Tissue Sarcomas in a Single Patient:An International Multicentre Review

Developing multiple soft tissue sarcomas (STSs) is a rare process, sparsely reported in the literature to date. Little is known about the pattern of disease development or outcomes in these patients. Patients were identified from three tertiary orthopaedic oncology centres in Canada and the UK. Patients who developed multiple extremity STSs were collated retrospectively from prospective oncology databases. A literature review using MEDLINE was also performed. Six patients were identified in the case series from these three institutions, and five studies were identified from the literature review. Overall, 17 patients were identified with a median age of 51 years (range: 19 to 77). The prevalence of this manifestation in STS patients is 1 in 1225. The median disease-free interval between diagnoses was 2.3 years (range: 0 to 19 years). Most patients developed the secondary STS in a metachronous pattern, the remaining, synchronously. The median survival after the first sarcoma was 6 years, and it was 1.6 years after the second sarcoma. The 5-year overall survival rate was 83.3% and 50% following the first and second STS diagnoses, respectively. A diagnosis of two STSs does not confer a worse prognosis than the diagnosis of a single STS. Developing a second STS is a rare event with no identifiable histological pattern of occurrence. Presentation in a metachronous pattern is more common. A high degree of vigilance is required in patients with a previous STS both to detect both local recurrence and to identify new masses remote from the previous STS site. Acquiring an early histological diagnosis should be attempted

Soft tissue substitutes in non-root coverage procedures: a systematic review and meta-analysis

Objectives The present systematic review compared the effectiveness of soft tissue substitutes (STSs) and autogenous free gingival grafts (FGGs) in non-root-coverage procedures to increase keratinized tissue (KT) width around teeth. Materials and methods Included studies fulfilled the following main eligibility criteria: (a) preclinical in vivo or human controlled trials using FGG as control, (b) non-root-coverage procedures, and (c) assessment of KT width. Meta-analysis was performed on the gain in KT width (primary outcome variable) and several secondary variables. Results Eight human trials with short observation time evaluating five different STSs were identified. FGG yielded consistently significantly (p < 0.001) larger increase in KT width irrespective whether the comparison regarded an acellular matrix or a tissue-engineered STS. Further, FGG yielded consistently ≥2 mm KT width postoperatively, while use of STS did not, in the few studies reporting on this outcome. On the other hand, STSs resulted in significantly better aesthetic outcomes and received greater patient preference (p < 0.001). Conclusions Based on relatively limited evidence, in non-root-coverage procedures, FGG (1) resulted consistently in significantly larger increase in KT width compared to STS and (2) yielded consistently ≥2 mm KT width postoperatively, while STSs did not. STSs yielded significantly better aesthetic outcomes, received greater patient preference, and appeared safe. Clinical relevance Larger and more predictable increase in KT width is achieved with FGG, but STSs may be considered when aesthetics is important. Clinical studies reporting relevant posttreatment outcomes, e.g., postop KT width ≥2 mm, on the long-term (>6 months) are warranted. Electronic supplementary material The online version of this article (doi:10.1007/s00784-016-2044-4) contains supplementary material, which is available to authorized users

Ultrasound-guided anterior axilla musculocutaneous nerve block

Purpose This paper presents a technique of ultrasound-guided localisation and block of the musculocutaneous nerve through the anterior wall of the axilla. Twenty patients (7 males and 13 females; mean age, 35 years) had axillary nerve block for upper extremity trauma. With the arm adducted, the ultrasound probe was positioned on the anterior axillary wall; the axillary artery, coracobrachialis and pectoralis major muscles and lateral cord of brachial plexus were visualised in cross section. With continuous imaging of the axillary artery in cross section, the ultrasound probe was slowly moved towards the biceps muscle until the musculocutaneous nerve appeared crossing the coracobrachialis muscle. After ultrasound localisation of the musculocutaneous nerve, the arm was abducted and externally rotated, and the nerve was identified with nerve stimulation and blocked. The quality of sensory and motor nerve block, as well as of ultrasound imaging were evaluated. Ultrasound-guided block of the musculocutaneous nerve was excellent and complete in 18 of the 20 patients. In two patients, the musculocutaneous nerve was fused with the median nerve and the nerve block was repeated successfully with the same technique. The quality of ultrasound imaging was excellent in all patients. No patient experienced pain or tourniquet discomfort during surgery, or any other nerve block-related complication. The anterior axillary ultrasound view provides for complete nerve block and imaging of the entire course of the musculocutaneous nerve and its relations with adjacent structures with excellent quality

Two-Stage Revision Protocol in Multidrug Resistant Periprosthetic Infection Following Total Hip Arthroplasty Using a Long Interval Between Stages

We retrospectively reviewed the medical records of 31 patients with periprosthetic hip infections attempting to evaluate the outcome of a two-stage revision protocol characterized by prolonged interim period (mean = 9.2 months, range 8-12 months) prior to the final re-implantation. In 3 cases (9.6%) the 1st stage was repeated after a mean period of 12.3 weeks due to relapse of infection. Five spacer dislocations occurred, not affecting the final clinical outcome after reimplantation, as evaluated by the Harris Hip Score. No protrusions or additional acetabular bone loss was noticed. Our proposed protocol is a simple, safe, efficient and reproducible treatment approach that may be successfully utilized predominantly when dealing with multidrug resistant pathogens. (C) 2015 Elsevier Inc. All rights reserved