26 research outputs found
Nanoscale Impurity Structures on the Surface of -wave Superconductors
We study the effects of nanoscale impurity structures on the local electronic
structure of -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 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