149 research outputs found

    Suppressed absolute negative conductance and generation of high-frequency radiation in semiconductor superlattices

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    We show that space-charge instabilities (electric field domains) in semiconductor superlattices are the attribute of absolute negative conductance induced by small constant and large alternating electric fields. We propose the efficient method for suppression of this destructive phenomenon in order to obtain a generation at microwave and THz frequencies in devices operating at room temperature. We theoretically proved that an unbiased superlattice with a moderate doping subjected to a microwave pump field provides a strong gain at third, fifth, seventh, etc. harmonics of the pump frequency in the conditions of suppressed domains.Comment: 8 pages. Development of cond-mat/0503216 . Version 2: Final version, erratum is include

    Multistable Pulse-like Solutions in a Parametrically Driven Ginzburg-Landau Equation

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    It is well known that pulse-like solutions of the cubic complex Ginzburg-Landau equation are unstable but can be stabilised by the addition of quintic terms. In this paper we explore an alternative mechanism where the role of the stabilising agent is played by the parametric driver. Our analysis is based on the numerical continuation of solutions in one of the parameters of the Ginzburg-Landau equation (the diffusion coefficient cc), starting from the nonlinear Schr\"odinger limit (for which c=0c=0). The continuation generates, recursively, a sequence of coexisting stable solutions with increasing number of humps. The sequence "converges" to a long pulse which can be interpreted as a bound state of two fronts with opposite polarities.Comment: 13 pages, 6 figures; to appear in PR

    Experience of the successful treatment with canakinumab of a patient with NLPC4-associated autoinflammatory syndrome with enterocolitis

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    The article shows the observation of rare NLPC4-associated autoinflammatory syndrome with enterocolitis and familial cold urticaria. Diagnosis is confirmed molecularly-genetically: previously not described mutation c.928C>T in the heterozygous state in NLRC4 gene is discovered by a method of the new generation sequencing. The use of a monoclonal antibody to the interleukin 1 canakinumab provided complete relief of fever and skin and intestinal symptoms in just 1 week of treatment. Later the signs of inflammation have disappeared completely; the patient’s quality of life improved and life-threatening complications were prevented. The above example demonstrates the high clinical efficacy of canakinumab in the patient with NLRC4-associated autoinflammatory syndrome and suggests promising therapeutic use of interleukin 1 blockers in such patients. There were no adverse events during canakinumab therapy

    Differences sustained between diffuse and limited forms of juvenile systemic sclerosis in expanded international cohort. www.juvenile-scleroderma.com

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    OBJECTIVES: To evaluate the baseline clinical characteristics of juvenile systemic sclerosis (jSSc) patients in the international Juvenile SSc Inception Cohort (jSScC), compare these characteristics between the classically defined diffuse (dcjSSc) and limited cutaneous (lcjSSc) subtypes, and among those with overlap features. METHODS: A cross-sectional study was performed using baseline visit data. Demographic, organ system evaluation, treatment, and patient and physician reported outcomes were extracted and summary statistics applied. Comparisons between dcjSSc and lcSSc subtypes and patients with and without overlap features were performed using Chi-square and Mann Whitney U-tests. RESULTS: At data extraction 150 jSSc patients were enrolled across 42 centers, 83% were Caucasian, 80% female, dcjSSc predominated (72%), and 17% of the cohort had overlap features. Significant differences were found between dcjSSc and lcjSSc regarding the modified Rodnan Skin Score, presence of Gottron's papules, digital tip ulceration, 6 Minute walk test, composite pulmonary and cardiac involvement. All more frequent in dcSSc except for cardiac involvement. DcjSSc patients had significantly worse scores for physician rated disease activity and damage. A significantly higher occurrence of Gottron's papules, musculoskeletal involvement and composite pulmonary involvement, and significantly lower frequency of Raynaud's phenomenon, were seen in those with overlap features. CONCLUSION: Results from a large international jSSc cohort demonstrate significant differences between dcjSSc and lcjSSc patients including more globally severe disease and increased frequency of ILD in dcjSSc patients, while those with lcSSc have more frequent cardiac involvement. Those with overlap features had an unexpected higher frequency of interstitial lung disease

    Perturbation theory for nearly integrable multi-component nonlinear PDEs

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    The Riemann-Hilbert problem associated with the integrable PDE is used as a nonlinear transformation of the nearly integrable PDE to the spectral space. The temporal evolution of the spectral data is derived with account for arbitrary perturbations and is given in the form of exact equations, which generate the sequence of approximate ODEs in successive orders with respect to the perturbation. For vector nearly integrable PDEs, embracing the vector NLS and complex modified KdV equations, the main result is formulated in a theorem. For a single vector soliton the evolution equations for the soliton parameters and first-order radiation are given in explicit formComment: Submitted to Journal of Mathematical Physics (References are corrected

    ДИАГНОСТИКА СИНДРОМА КАВАСАКИ И ОПЫТ ПРИМЕНЕНИЯ ИММУНОГЛОБУЛИНА НОРМАЛЬНОГО ЧЕЛОВЕЧЕСКОГО ДЛЯ ВНУТРИВЕННОГО ВВЕДЕНИЯ

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    The article presents a case of late diagnosis of cutaneomucosal lymphonodular syndrome (Kawasaki syndrome). The child featured fever, mucosal lesion (conjunctivitis, stomatitis), rash, thick edemas on arms and feet, arthritis and coronaritis. Initial therapy proved ineffective. Pathogenetic therapy, which proved to be rather effective, was prescribed after diagnosis was confirmed. The authors present a case of successful use of normal human immunoglobulin for intravenous injections in the dose of 2 g/kg of body weight per course in combination with acetylsalicylic acid in the dose of 80 mg/kg per day. Body temperature decreased down to subfebrile figures and foot pain attenuated as early as after 1 day of treatment. Fever, rash, stomatitis and conjunctivitis terminated, edemas of limbs and arthritic manifestations attenuated considerably and laboratory parameters of disease activity normalized after 1 week (ESR and CRP). Inflammation of coronary arteries terminated after 3 weeks. No adverse events in the setting of immunoglobulin therapy were observed.  В статье представлен случай поздней диагностики слизисто-кожного лимфонодулярного синдрома (синдрома Кавасаки). У ребенка отмечались лихорадка, поражение слизистых оболочек (конъюнктивит, стоматит), сыпь, плотные отеки кистей и стоп, артрит, коронарит. Инициальная терапия оказалась неэффективна. При подтверждении диагноза назначена патогенетическая терапия с хорошим эффектом. Авторы представляют успешное применение иммуноглобулина нормального человеческого для внутривенного введения в дозе 2 г/кг массы тела на курс в сочетании с ацетилсалициловой кислотой в дозе 80 мг/кг в сут. Уже через 1 сут лечения температура у ребенка снизилась до субфебрильных цифр, уменьшились боли в стопах. Через 1 нед купировались лихорадка, сыпь, стоматит, конъюнктивит; значительно уменьшились отеки конечностей и явления артрита, нормализовались лабораторные показатели активности болезни (СОЭ и СРБ). Через 3 нед купировалось воспаление в коронарных артериях. Нежелательных явлений на фоне терапии иммуноглобулином у ребенка не отмечалось.

    Aberrant crossed corticospinal facilitation in muscles distant from a spinal cord injury.

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    Crossed facilitatory interactions in the corticospinal pathway are impaired in humans with chronic incomplete spinal cord injury (SCI). The extent to which crossed facilitation is affected in muscles above and below the injury remains unknown. To address this question we tested 51 patients with neurological injuries between C2-T12 and 17 age-matched healthy controls. Using transcranial magnetic stimulation we elicited motor evoked potentials (MEPs) in the resting first dorsal interosseous, biceps brachii, and tibialis anterior muscles when the contralateral side remained at rest or performed 70% of maximal voluntary contraction (MVC) into index finger abduction, elbow flexion, and ankle dorsiflexion, respectively. By testing MEPs in muscles with motoneurons located at different spinal cord segments we were able to relate the neurological level of injury to be above, at, or below the location of the motoneurons of the muscle tested. We demonstrate that in patients the size of MEPs was increased to a similar extent as in controls in muscles above the injury during 70% of MVC compared to rest. MEPs remained unchanged in muscles at and within 5 segments below the injury during 70% of MVC compared to rest. However, in muscles beyond 5 segments below the injury the size of MEPs increased similar to controls and was aberrantly high, 2-fold above controls, in muscles distant (>15 segments) from the injury. These aberrantly large MEPs were accompanied by larger F-wave amplitudes compared to controls. Thus, our findings support the view that corticospinal degeneration does not spread rostral to the lesion, and highlights the potential of caudal regions distant from an injury to facilitate residual corticospinal output after SCI

    Опыт успешного лечения канакинумабом пациентки с NLPC4-ассоциированным аутовоспалительным синдромом с энтероколитом

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    The article shows the observation of rare NLPC4-associated autoinflammatory syndrome with enterocolitis and familial cold urticaria. Diagnosis is confirmed molecularly-genetically: previously not described mutation c.928C>T in the heterozygous state in NLRC4 gene is discovered by a method of the new generation sequencing. The use of a monoclonal antibody to the interleukin 1 canakinumab provided complete relief of fever and skin and intestinal symptoms in just 1 week of treatment. Later the signs of inflammation have disappeared completely; the patient’s quality of life improved and life-threatening complications were prevented. The above example demonstrates the high clinical efficacy of canakinumab in the patient with NLRC4-associated autoinflammatory syndrome and suggests promising therapeutic use of interleukin 1 blockers in such patients. There were no adverse events during canakinumab therapy.Представлено наблюдение редкого NLPC4-ассоциированного аутовоспалительного синдрома с энтероколитом и семейной холодовой крапивницей. Диагноз подтвержден молекулярно-генетически: методом секвенирования нового поколения обнаружена ранее не описанная мутация c.928C>T в гетерозиготном состоянии в гене NLRC4. Применение моноклонального антитела к интерлейкину 1 канакинумаба уже через 1 нед лечения обеспечило полное купирование лихорадки, кожного и кишечного синдрома. В дальнейшем зафиксировано полное исчезновение признаков воспаления, повышение качества жизни больной, а также предотвращение развития жизнеугрожающих осложнений. Приведенный клинический пример демонстрирует высокую эффективность канакинумаба у больной с NLRC4-ассоциированным аутовоспалительным синдромом и свидетельствует о перспективности терапевтического применения блокатора интерлейкина 1 у таких пациентов. Нежелательных явлений на фоне терапии канакинумабом не зарегистрировано

    Immunoglobulin, glucocorticoid, or combination therapy for multisystem inflammatory syndrome in children: a propensity-weighted cohort study

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    Background: Multisystem inflammatory syndrome in children (MIS-C), a hyperinflammatory condition associated with SARS-CoV-2 infection, has emerged as a serious illness in children worldwide. Immunoglobulin or glucocorticoids, or both, are currently recommended treatments. Methods: The Best Available Treatment Study evaluated immunomodulatory treatments for MIS-C in an international observational cohort. Analysis of the first 614 patients was previously reported. In this propensity-weighted cohort study, clinical and outcome data from children with suspected or proven MIS-C were collected onto a web-based Research Electronic Data Capture database. After excluding neonates and incomplete or duplicate records, inverse probability weighting was used to compare primary treatments with intravenous immunoglobulin, intravenous immunoglobulin plus glucocorticoids, or glucocorticoids alone, using intravenous immunoglobulin as the reference treatment. Primary outcomes were a composite of inotropic or ventilator support from the second day after treatment initiation, or death, and time to improvement on an ordinal clinical severity scale. Secondary outcomes included treatment escalation, clinical deterioration, fever, and coronary artery aneurysm occurrence and resolution. This study is registered with the ISRCTN registry, ISRCTN69546370. Findings: We enrolled 2101 children (aged 0 months to 19 years) with clinically diagnosed MIS-C from 39 countries between June 14, 2020, and April 25, 2022, and, following exclusions, 2009 patients were included for analysis (median age 8·0 years [IQR 4·2–11·4], 1191 [59·3%] male and 818 [40·7%] female, and 825 [41·1%] White). 680 (33·8%) patients received primary treatment with intravenous immunoglobulin, 698 (34·7%) with intravenous immunoglobulin plus glucocorticoids, 487 (24·2%) with glucocorticoids alone; 59 (2·9%) patients received other combinations, including biologicals, and 85 (4·2%) patients received no immunomodulators. There were no significant differences between treatments for primary outcomes for the 1586 patients with complete baseline and outcome data that were considered for primary analysis. Adjusted odds ratios for ventilation, inotropic support, or death were 1·09 (95% CI 0·75–1·58; corrected p value=1·00) for intravenous immunoglobulin plus glucocorticoids and 0·93 (0·58–1·47; corrected p value=1·00) for glucocorticoids alone, versus intravenous immunoglobulin alone. Adjusted average hazard ratios for time to improvement were 1·04 (95% CI 0·91–1·20; corrected p value=1·00) for intravenous immunoglobulin plus glucocorticoids, and 0·84 (0·70–1·00; corrected p value=0·22) for glucocorticoids alone, versus intravenous immunoglobulin alone. Treatment escalation was less frequent for intravenous immunoglobulin plus glucocorticoids (OR 0·15 [95% CI 0·11–0·20]; p<0·0001) and glucocorticoids alone (0·68 [0·50–0·93]; p=0·014) versus intravenous immunoglobulin alone. Persistent fever (from day 2 onward) was less common with intravenous immunoglobulin plus glucocorticoids compared with either intravenous immunoglobulin alone (OR 0·50 [95% CI 0·38–0·67]; p<0·0001) or glucocorticoids alone (0·63 [0·45–0·88]; p=0·0058). Coronary artery aneurysm occurrence and resolution did not differ significantly between treatment groups. Interpretation: Recovery rates, including occurrence and resolution of coronary artery aneurysms, were similar for primary treatment with intravenous immunoglobulin when compared to glucocorticoids or intravenous immunoglobulin plus glucocorticoids. Initial treatment with glucocorticoids appears to be a safe alternative to immunoglobulin or combined therapy, and might be advantageous in view of the cost and limited availability of intravenous immunoglobulin in many countries. Funding: Imperial College London, the European Union's Horizon 2020, Wellcome Trust, the Medical Research Foundation, UK National Institute for Health and Care Research, and National Institutes of Health
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