Influence of the heterointerface sharpness on exciton recombination dynamics in an ensemble of (In,Al)As/AlAs quantum dots with indirect band-gap

The dynamics of exciton recombination in an ensemble of indirect band-gap (In,Al)As/AlAs quantum dots with type-I band alignment is studied. The lifetime of confined excitons which are indirect in momentum-space is mainly influenced by the sharpness of the heterointerface between the (In,Al)As quantum dot and the AlAs barrier matrix. Time-resolved photoluminescence experiments and theoretical model calculations reveal a strong dependence of the exciton lifetime on the thickness of the interface diffusion layer. The lifetime of excitons with a particular optical transition energy varies because this energy is obtained for quantum dots differing in size, shape and composition. The different exciton lifetimes, which result in photoluminescence with non-exponential decay obeying a power-law function, can be described by a phenomenological distribution function, which allows one to explain the photoluminescence decay with one fitting parameter only.Comment: 10 pages, 7 figure

Comparative analysis of anxiety-depressive spectrum disorders in patients with rheumatic diseases

Research objective - comparative analysis of incidence and structure of anxiety-depressive spectrum disorders (ADD) in patients with various rheumatic diseases (RD). Materials and methods. 613 patients with RD were enrolled in the study: 180 with a reliable diagnosis of systemic lupus erythematosus (SLE), 128 with rheumatoid arthritis (RA), 110 with systemic sclerosis (SSc), 115 with Behcet's disease (BD), 80 with primary Sjögren's syndrome (pSS). Female prevailed in all groups (95% of patients with pSS, 88,2% - SSc, 87,2% - RA, 85,5% of SLE) except BD patients (70% male). The mean age was 42.3±1.54 years and was lower in patients with BD (33.3±0.98 years) and SLE (34.6±0.93 years) compared to patients with SSc (49.9±2.47 years), RA (47.4±0.99 years) and pSS (46.2±2.3 years). The mean RD duration was 130,0±8,65 months and was more at BD - 148,5±10,4 months, pSS - 141,6±8,92 months, RA - 138,4±10,1months, and less at SLE - 134,9±8,8 months and SSc - 87,0±5,04 months. The mean SLE activity index SLEDAI was 9,13±0,63 points (high), RA (DAS28) - 5,26±0,17 points (high), BD (BDCAF) - 3,79±0,2 points (moderate) and SSc by G. Valentini - 1,1±0,20 points (moderate). Glucocorticoids took 100% of patients with pSS, 91,1% - SLE, 90% - SSc, 87% - BD and 67,2% - RA patients; conventional disease modifying anti-rheumatic drugs (cDMARDs) took 90% of patients with SSc, 84% - BD, 79,6% - RA, 68% - pSS, 40,6% - SLE. Biologic DMARDs took 32% of patients with RA, 17,4% - BD, 7,3% - SSc and 7,2% - SLE. Mental disorders were diagnosed by psychiatrist as a result of screening by the hospital anxiety and depression scale (HADS) and in semi-structured interview in accordance with the ICD-10/ DSM-IV. The severity of depression was evaluated by Montgomery-Asberg Depression Rating Scale (MADRS) and anxiety - by Hamilton Anxiety Rating Scale (HAM-A). Projective psychological methods were used for cognitive impairment detection. Results. Screening of depressive disorders (HADS-D≥8) was positive in 180 (29,4%) patients with RD, including 74 (41%) patients with SLE, 38 (35%) - SSc, 29 (23%) - RA, 23 (20%) - BD and 16 (20%) - pSS; anxiety disorders (HADS-A≥8) - in 272 (44,4%) patients, including 66 (52%) patients with RA, 40 (50%) - pSS, 77 (43%) - SLE, 45 (41%) - SSc and 44 (38%) - BD. In accordance with the ICD-10/ DSM-IV depressive disorders have been identified in 389 (63%) patients, including 94 (73%) patients with RA, 71 (64,5%) - SSc, 69 (60%) - BD, 90 (50%) - SLE and 39 (49%) - pSS; anxiety disorders - in 377 (61,5%) patients, including 20 (25%) patients with pSS, 44 (24,5%) - SLE, 29 (23%) - RA, 20 (17%) - BD and 7 (6,4%) - SSc. Conclusion. Anxiety-depressive spectrum disorders are typical for most patients with RA, SLE, SSc, pSS and BD. ADDs diagnosis in RD patients with the use of the HADS did not reveal a significant proportion. To obtain objective data on the frequency and structure of ADDs, psychopathological and clinical psychological diagnosis is necessary

FACTORS INFLUENCING THE EFFICIENCY OF THERAPY IN PATIENTS WITH RHEUMATOID ARTHRITIS: THE ROLE OF COMORBID MENTAL AND SOMATIC DISEASES

The response rate to therapy for rheumatoid arthritis (RA) rarely exceeds 60%. Mental disorders (MDs) of the anxiety-depressive spectrum (ADS) and cognitive impairment (CI) substantially affect the evaluation of the efficiency of RA therapy. Adequate psychopharmacotherapy is one of the possible approaches to optimizing the treatment of RA. The factors influencing the efficiency of RA therapy with standard disease-modifying antirheumatic drugs (DMARDs) and biological agents (BAs) in combination with adequate psychopharmacotherapy have not been previously identified. Objective: to determine the predictors of response to therapy in patients with RA receiving DMARDs and BAs with or without adequate psychopharmacotherapy for ADS disorders. Subjects and methods. The investigation included 128 patients (13% men and 87% women) with a reliable diagnosis of RA. At baseline, 75.1% of patients received DMARDs; 7.8% – BAs. ADS disorders were detected in 123 (96.1%) patients. Psychopharmacotherapy was offered to all the patients with MDs; 52 patients agreed to treatment and 71 refused. The following therapeutic groups were identified according to the performed therapy: 1) DMARDs (n = 39); 2) DMARDs + psychopharmacotherapy (n = 43); 3) DMARDs + BAs (n = 32); 4) DMARDs + BAs + psychopharmacotherapy (n = 9). The changes of MDs symptoms and the outcomes of RA were assessed in 83 (67.5%) patients at five-year follow-up. The efficiency of RA therapy was evaluated with DAS28 (EULAR criteria). Predictors of response to therapy were determined using linear regression modeling. Results and discussion. At 5 years, 22 (26.5%) and 37 (44.6%) patients were recorded to show good and moderate responses to therapy, respectively; 24 (28.9%) patients were non-respondents. The linear regression model included 14 factors (p<0.001). The high values of DAS28 (β=0.258) at the inclusion; belonging to therapeutic groups 2 (β=0.267), 3 (β=0.235), and 4 (β=0.210), the absence of diabetes mellitus (β=-0.230), and experience in using glucocorticoids (β=-0.230) were associated with a high likelihood of response to therapy; high body mass index (β=-0.200) and long RA duration (β=-0,181), a high level of rheumatoid factor (β=-0.176), a history of myocardial infarction (β=-0.153), schizotypic disorder (β=-0.132), and extra-articular manifestations of RA (β=-0.106), and older age (β=-0.102) were related to a low probability of response. The area under the ROC curve for the model was 0.99 (p><0.001). Conclusion. BA therapy and psychopharmacotherapy, along with younger age, shorter duration and high activity of RA, a low level of rheumatoid factor, lower body mass index, the absence of diabetes mellitus, myocardial infarction, and extra-articular manifestations of RA in the history, schizotypic disorder, and experience in using glucocorticoids are associated with a greater likelihood of a good and moderate treatment response. Keywords: rheumatoid arthritis; mental disorders; disease-modifying antirheumatic drugs; biological agents; efficiency of therapy; predictors; psychopharmacotherapy; therapy adherence><0.001). The high values of DAS28 (β=0.258) at the inclusion; belonging to therapeutic groups 2 (β=0.267), 3 (β=0.235), and 4 (β=0.210), the absence of diabetes mellitus (β=-0.230), and experience in using glucocorticoids (β=-0.230) were associated with a high likelihood of response to therapy; high body mass index (β=-0.200) and long RA duration (β=-0,181), a high level of rheumatoid factor (β=-0.176), a history of myocardial infarction (β=-0.153), schizotypic disorder (β=-0.132), and extra-articular manifestations of RA (β=-0.106), and older age (β=-0.102) were related to a low probability of response. The area under the ROC curve for the model was 0.99 (p<0.001). Conclusion. BA therapy and psychopharmacotherapy, along with younger age, shorter duration and high activity of RA, a low level of rheumatoid factor, lower body mass index, the absence of diabetes mellitus, myocardial infarction, and extra-articular manifestations of RA in the history, schizotypic disorder, and experience in using glucocorticoids are associated with a greater likelihood of a good and moderate treatment response. Keywords: rheumatoid arthritis; mental disorders; disease-modifying antirheumatic drugs; biological agents; efficiency of therapy; predictors; psychopharmacotherapy; therapy adherence><0.001). Conclusion. BA therapy and psychopharmacotherapy, along with younger age, shorter duration and high activity of RA, a low level of rheumatoid factor, lower body mass index, the absence of diabetes mellitus, myocardial infarction, and extra-articular manifestations of RA in the history, schizotypic disorder, and experience in using glucocorticoids are associated with a greater likelihood of a good and moderate treatment response