6,894 research outputs found

    Submicron gate InP power MISFET's with improved output power density at 18 and 20 GHz

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    The microwave characteristics are presented at 18 and 20 GHz of submicron gate indium phosphide (InP) metal-insulator-semiconductor field-effect transistors (MISFET's) for high output power density applications. InP power MISFET's were fabricated and the output power density was investigated as a function of drain-source spacing. The best output power density and gain were obtained for drain-source spacing of 3 microns. The output power density is 2.7 times greater than was previously measured for InP MISFET's at 18 and 20 GHz, and the power-added efficiency also increased

    Bound State Wave Functions through the Quantum Hamilton - Jacobi Formalism

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    The bound state wave functions for a wide class of exactly solvable potentials are found utilizing the quantum Hamilton-Jacobi formalism. It is shown that, exploiting the singularity structure of the quantum momentum function, until now used only for obtaining the bound state energies, one can straightforwardly find both the eigenvalues and the corresponding eigenfunctions. After demonstrating the working of this approach through a number of solvable examples, we consider Hamiltonians, which exhibit broken and unbroken phases of supersymmetry. The natural emergence of the eigenspectra and the wave functions, in both the unbroken and the algebraically non-trivial broken phase, demonstrates the utility of this formalism.Comment: replaced with the journal versio

    Soliton response to transient trap variations

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    The response of bright and dark solitons to rapid variations in an expulsive longitudinal trap is investigated. We concentrate on the effect of transient changes in the trap frequency in the form of temporal delta kicks and the hyperbolic cotangent functions. Exact expressions are obtained for the soliton profiles. This is accomplished using the fact that a suitable linear Schrodinger stationary state solution in time can be effectively combined with the solutions of non-linear Schrodinger equation, for obtaining solutions of the Gross-Pitaevskii equation with time dependent scattering length in a harmonic trap. Interestingly, there is rapid pulse amplification in certain scenarios

    Molecular analysis of Salmonella paratyphi A from an outbreak in New Delhi, India.

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    In the context of emerging infectious diseases, enteric fever caused by Salmonella paratyphi A deserves increased attention and vigilance, although its severity is often milder than that of S. typhi disease. Outbreaks associated with this organism are exceedingly rare but have recently been reported in India (1) and Thailand. In India, the first reported outbreak of disease associated with S. paratyphi A (1) provided an opportunity to study the molecular epidemiology of infection caused by this organism

    Routine blood monitoring in maintenance immunoglobulin treatment of inflammatory neuropathy: Is it clinically relevant?

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    Background: Pre-treatment screening for IgA deficiency and close monitoring of full blood count(FBC) and renal function is recommended with intravenous immunoglobulin(IVIg) therapy in neurological diseases. / Aims: To examine the frequency of biochemically defined and clinically significant episodes of treatment associated haemolysis, neutropenia, thrombocytopenia and acute kidney injury(AKI) in a cohort of patients on maintenance Immunoglobulin(Ig) therapy for inflammatory neuropathy. / Methods: A retrospective review of routine blood monitoring in patients from two UK specialist peripheral nerve centres. Accepted definitions for clinically and biochemically significant haemolysis, neutropenia, thrombocytopenia and AKI were used. / Results: 1919 infusion episodes in 90 patients were analysed. Age(mean(S.D)) = 58.09(14.4)years, 63% male, 72% CIDP(28% MMN), 97% IVIg(3% SCIg). Dose = 1.57(0.79)g/kg/month or 97.1(37.3)g/infusion, frequency:3.9(1.4) weeks. Relative IgA deficiency was noted in 2 individuals (prevalence:2.2%, 95%C.I.:0–5.2) who received a combined total of 38 infusions(3800 g IVIg) without adverse event. No clinically significant episodes of haemolysis, neutropenia, thrombocytopenia or AKI occurred in relation to treatment. An asymptomatic drop>10 g/L haemoglobin(Hb) occurred in 3.5%(95%CI:2.7–4.3) of treatment episodes in 38 individuals, mean reduction:17.7(7.4)g/L; lowest Hb:86 g/L. Lower pre-treatment haemoglobin correlated with risk of recurrent Ig-related drop(p:0.007). Two patients with chronic renal failure(stage 1 and 3) received 28(IV) and 104(SC) infusions respectively(6416 g) without impact on estimated glomerular filtration rate(eGFR). / Conclusions: No clinically significant Ig-related episodes of haemolysis or AKI were identified in this representative cohort. This suggests that routine monitoring is not essential in long-term Ig use but should be considered when clinically indicated

    Association of plasma neurofilament light chain with disease activity in chronic inflammatory demyelinating polyradiculoneuropathy

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    BACKGROUND AND PURPOSE: This study was undertaken to explore associations between plasma neurofilament light chain (pNfL) concentration (pg/ml) and disease activity in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and examine the usefulness of pNfL concentrations in determining disease remission. METHODS: We examined pNfL concentrations in treatment-naïve CIDP patients (n = 10) before and after intravenous immunoglobulin (IVIg) induction treatment, in pNfL concentrations in patients on maintenance IVIg treatment who had stable (n = 15) versus unstable disease (n = 9), and in clinically stable IVIg-treated patients (n = 10) in whom we suspended IVIg to determine disease activity and ongoing need for maintenance IVIg. pNfL concentrations in an age-matched healthy control group were measured for comparison. RESULTS: Among treatment-naïve patients, pNfL concentration was higher in patients before IVIg treatment than healthy controls and subsequently reduced to be comparable to control group values after IVIg induction. Among CIDP patients on IVIg treatment, pNfL concentration was significantly higher in unstable patients than stable patients. A pNFL concentration > 16.6 pg/ml distinguished unstable treated CIDP from stable treated CIDP (sensitivity = 86.7%, specificity = 66.7%, area under receiver operating characteristic curve = 0.73). Among the treatment withdrawal group, there was a statistically significant correlation between pNfL concentration at time of IVIg withdrawal and the likelihood of relapse (r = 0.72, p < 0.05), suggesting an association of higher pNfL concentration with active disease. CONCLUSIONS: pNfL concentrations may be a sensitive, clinically useful biomarker in assessing subclinical disease activity

    Geriatric Conditions Are Associated With Decreased Anticoagulation Use in Long-Term Care Residents With Atrial Fibrillation

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    Background Anticoagulation is the mainstay for stroke prevention in patients with atrial fibrillation, but concerns about bleeding inhibit its use in residents of long-term care facilities. Risk-profiling algorithms using comorbid disease information (eg, CHADS2 and ATRIA [Anticoagulation and Risk Factors in Atrial Fibrillation]) have been available for years. In the long-term care setting, however, providers and residents may place more value on geriatric conditions such as mobility impairment, activities of daily living dependency, cognitive impairment, low body mass index, weight loss, and fall history. Methods and Results Using a retrospective cohort design, we measured the association between geriatric conditions and anticoagulation use and type. After merging nursing home assessments containing information about geriatric conditions (Minimum Data Set 2015) with Medicare Part A 2014 to 2015 claims and prescription claims (Medicare Part D) 2015 to 2016, we identified 228 741 residents with atrial fibrillation and elevated stroke risk (CHA2DS2-VASc score \u3e /=2) for our main analysis. Recent fall, activities of daily living dependency, moderate and severe cognitive impairment, low body mass index, and unintentional weight loss were all associated with lower anticoagulation use even after adjustment for multiple predictors of stroke and bleeding (odds ratios ranging from 0.51 to 0.91). Residents with recent fall, low body mass index, and unintentional weight loss were more likely to be using a direct oral anticoagulant, although the magnitude of this effect was smaller. Conclusions Geriatric conditions were associated with lower anticoagulation use. Preventing stroke in these residents with potential for further physical and cognitive impairment would appear to be of paramount significance, although the net benefit of anticoagulation in these individuals warrants further research
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