1,329 research outputs found
High field magneto-transport in high mobility gated InSb/InAlSb quantum well heterostructures
We present high field magneto-transport data from a range of 30nm wide
InSb/InAlSb quantum wells. The low temperature carrier mobility of the samples
studied ranged from 18.4 to 39.5 m2V-1s-1 with carrier densities between
1.5x1015 and 3.28x1015 m-2. Room temperature mobilities are reported in excess
of 6 m2V-1s-1. It is found that the Landau level broadening decreases with
carrier density and beating patterns are observed in the magnetoresistance with
non-zero node amplitudes in samples with the narrowest broadening despite the
presence of a large g-factor. The beating is attributed to Rashba splitting
phenomenon and Rashba coupling parameters are extracted from the difference in
spin populations for a range of samples and gate biases. The influence of
Landau level broadening and spin-dependent scattering rates on the observation
of beating in the Shubnikov-de Haas oscillations is investigated by simulations
of the magnetoconductance. Data with non-zero beat node amplitudes are
accompanied by asymmetric peaks in the Fourier transform, which are
successfully reproduced by introducing a spin-dependent broadening in the
simulations. It is found that the low-energy (majority) spin up state suffers
more scattering than the high-energy (minority) spin down state and that the
absence of beating patterns in the majority of (lower density) samples can be
attributed to the same effect when the magnitude of the level broadening is
large
Evidence for Nodal superconductivity in SrScFePO
Point contact Andreev reflection spectra have been taken as a function of
temperature and magnetic field on the polycrystalline form of the newly
discovered iron-based superconductor Sr2ScFePO3. A zero bias conductance peak
which disappears at the superconducting transition temperature, dominates all
of the spectra. Data taken in high magnetic fields show that this feature
survives until 7T at 2K and a flattening of the feature is observed in some
contacts. Here we inspect whether these observations can be interpreted within
a d-wave, or nodal order parameter framework which would be consistent with the
recent theoretical model where the height of the P in the Fe-P-Fe plane is key
to the symmetry of the superconductivity. However, in polycrystalline samples
care must be taken when examining Andreev spectra to eliminate or take into
account artefacts associated with the possible effects of Josephson junctions
and random alignment of grains.Comment: Published versio
Senile Systemic Amyloidosis: Clinical Features at Presentation and Outcome
Background Cardiac amyloidosis is a fatal disease whose prognosis and treatment rely on identification of the amyloid type. In our aging population transthyretin amyloidosis (ATTRwt) is common and must be differentiated from other amyloid types. We report the clinical presentation, natural history, and prognostic features of ATTRwt compared with cardiac‐isolated AL amyloidosis and calculate the probability of disease diagnosis of ATTRwt from baseline factors.
Methods and Results All patients with biopsy‐proven ATTRwt (102 cases) and isolated cardiac AL (36 cases) seen from 2002 to 2011 at the UK National Amyloidosis Center were included. Median survival from the onset of symptoms was 6.07 years in the ATTRwt group and 1.7 years in the AL group. Positive troponin, a pacemaker, and increasing New York Heart Association (NYHA) class were associated with worse survival in ATTRwt patients on univariate analysis. All patients with isolated cardiac AL and 24.1% of patients with ATTRwt had evidence of a plasma cell dyscrasia. Older age and lower N‐terminal pro‐B‐type natriuretic peptide (NT pro‐BNP) were factors significantly associated with ATTRwt. Patients aged 70 years and younger with an NT pro‐BNP <183 pmol/L were more likely to have ATTRwt, as were patients older than 70 years with an NT pro‐BNP <1420 pmol/L.
Conclusions Factors at baseline associated with a worse outcome in ATTRwt are positive troponin T, a pacemaker, and NYHA class IV symptoms. The age of the patient at diagnosis and NT pro‐BNP level can aid in distinguishing ATTRwt from AL amyloidosis
Room temperature ballistic transport in InSb quantum well nanodevices
We report the room temperature observation of significant ballistic electron
transport in shallow etched four-terminal mesoscopic devices fabricated on an
InSb/AlInSb quantum well (QW) heterostructure with a crucial partitioned
growth-buffer scheme. Ballistic electron transport is evidenced by a negative
bend resistance signature which is quite clearly observed at 295 K and at
current densities in excess of 10 A/cm. This demonstrates
unequivocally that by using effective growth and processing strategies, room
temperature ballistic effects can be exploited in InSb/AlInSb QWs at practical
device dimensions
Lysozyme amyloid: evidence for the W64R variant by proteomics in the absence of the wild type protein
Being Warm Being Happy: fuel poverty and adults with intellectual disabilities
Self-determination has been acknowledged as a criticalconstruct for people with intellectual disability (ID), given the benefits itspromotion entails towards an enhanced quality of life..
Interrupting Antiretroviral Treatment in HIV Cure Research: Scientific and Ethical Considerations
Over the past several years there has been intense activity directed at the possibility of achieving remission or eradication of HIV infection. Current assays for the measurement of latent HIV are insufficient to demonstrate complete clearance of replication-competent HIV. Therefore, the ultimate test for assessing whether investigational interventions have resulted in HIV remission or eradication is to interrupt standard antiretroviral therapy (ART) in a carefully controlled clinical trial setting. These procedures, known as analytic treatment interruptions (ATIs), raise important scientific and ethical questions. The lack of definitive assays for measuring viral reservoirs not only makes research on HIV remission or cure challenging, it also affects the ability to assess risks from ATIs themselves. In spite of these challenges, basic ethical criteria can be met with careful study design and close monitoring. In this brief report we outline ethical standards for HIV cure research involving ATIs. These criteria should be revisited as the science evolves
Renal Transplant Outcomes in Amyloidosis
Background:
Outcomes after renal transplantation have traditionally been poor in systemic amyloid A (AA) amyloidosis and systemic light chain (AL) amyloidosis, with high mortality and frequent recurrent disease. We sought to compare outcomes with matched transplant recipients with autosomal dominant polycystic kidney disease (ADPKD) and diabetic nephropathy (DN), and identify factors predictive of outcomes.
Methods:
We performed a retrospective cohort study of 51 systemic AL and 48 systemic AA amyloidosis patients undergoing renal transplantation. Matched groups were generated by propensity score matching. Patient and death-censored allograft survival were compared via Kaplan–Meier survival analyses, and assessment of clinicopathological features predicting outcomes via Cox proportional hazard analyses.
Results:
One-, 5- and 10-year death-censored unadjusted graft survival was, respectively, 94, 91 and 78% for AA amyloidosis, and 98, 93 and 93% for AL amyloidosis; median patient survival was 13.1 and 7.9 years, respectively. Patient survival in AL and AA amyloidosis was comparable to DN, but poorer than ADPKD [hazard ratio (HR) = 3.12 and 3.09, respectively; P 12 mm (HR = 26.58; P = 0.03), while survival was predicted by haematologic response (very good partial or complete response; HR = 0.07; P = 0.018). In AA amyloidosis, recurrent amyloid was associated with elevated serum amyloid A concentration but not with outcomes.
Conclusions:
Renal transplantation outcomes for selected patients with AA and AL amyloidosis are comparable to those with DN. In AL amyloidosis, IVSd thickness and achievement of deep haematologic response pre-transplant profoundly impact patient survival
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