279 research outputs found

    Addition of H_2O and O_2 to Acetone and Dimethylsulfoxide Ligated Uranyl(V) Dioxocations

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    Gas-phase complexes of the formula [UO_2(lig)]^+ (lig = acetone (aco) or dimethylsulfoxide (dmso)) were generated by electrospray ionization (ESI) and studied by tandem ion-trap mass spectrometry to determine the general effect of ligand charge donation on the reactivity of UO_2^+ with respect to water and dioxygen. The original hypothesis that addition of O_2 is enhanced by strong σ-donor ligands bound to UO_2^+ is supported by results from competitive collision-induced dissociation (CID) experiments, which show near exclusive loss of H_2O from [UO_2(dmso)(H_2O)(O_2)]^+, whereas both H_2O and O_2 are eliminated from the corresponding [UO_2(aco)(H_2O)(O_2)]^+ species. Ligand-addition reaction rates were investigated by monitoring precursor and product ion intensities as a function of ion storage time in the ion-trap mass spectrometer: these experiments suggest that the association of dioxygen to the UO_2^+ complex is enhanced when the more basic dmso ligand was coordinated to the metal complex. Conversely, addition of H_2O is favored for the analogous complex ion that contains an aco ligand. Experimental rate measurements are supported by density function theory calculations of relative energies, which show stronger bonds between UO_2^+ and O_2 when dmso is the coordinating ligand, whereas bonds to H_2O are stronger for the aco complex

    Association of ECG characteristics with clinical and echocardiographic outcome to CRT in a non-LBBB patient population

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    Purpose: Effectiveness of cardiac resynchronization therapy (CRT) in patients without left bundle branch block (non-LBBB) QRS morphology is limited. Additional selection criteria are needed to identify these patients. Methods: Seven hundred ninety consecutive patients with non-LBBB morphology, who received a CRT-device in 3 university centers in the Netherlands, were selected. Pre-implantation 12-lead ECGs were evaluated on morphology, duration, and area of the QRS complex, as well as on PR interval, left ventricular activation time (LVAT), and the presence of fragmented QRS (fQRS). Association of these ECG features with the primary endpoint: a combination of left ventricular assist device (LVAD) implantation, cardiac transplantation and all-cause mortality, and secondary endpoint—echocardiographic reduction of left ventricular end-systolic volume (LVESV)—were evaluated. Results: The primary endpoint occurred more often in non-LBBB patients with with PR interval ≥ 230ms, QRS area < 109μVs, and with fQRS. Multivariable regression analysis showed independent associations of QRS area (HR 2.33 [1.44, 3.77], p = 0.001) and PR interval (HR 2.03 [1.51, 2.74], p < 0.001) only. Mean LVESV reduction was significantly lower in patients with baseline RBBB, QRS duration < 150 ms, PR interval ≥ 230 ms, and in QRS area < 109 μVs. Multivariable regression analyses only showed significant associations between QRS area ≥ 109 μVs (OR 2.00 [1.09, 3.66] p = 0.025) and probability of echocardiographic response to CRT. Conclusions: In the heterogeneous non-LBBB patient population, QRS area and PR prolongation rather than traditional QRS duration and morphology are associated to both clinical and echocardiographic outcomes of CRT

    Heart Size Corrected Electrical Dyssynchrony and Its Impact on Sex-specific Response to Cardiac Resynchronization Therapy

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    Background - Women are less likely to receive cardiac resynchronization therapy (CRT), yet, they are more responsive to the therapy and respond at shorter QRS duration. The present study hypothesized that a relatively larger left ventricular (LV) electrical dyssynchrony in smaller hearts contributes to the better CRT response in women. For this the vectorcardiography-derived QRS area is used, since it allows for a more detailed quantification of electrical dyssynchrony compared to conventional electrocardiographic markers. Methods - Data from a multicenter registry of 725 CRT patients (median follow-up: 4.2 years [IQR: 2.7-6.1]) were analyzed. Baseline electrical dyssynchrony was evaluated using the QRS area, and the corrected QRS area for heart size using the LV end-diastolic volume (QRSarea/LVEDV). Impact of the QRSarea/LVEDV-ratio on the association between sex and LV reverse remodeling (end-systolic volume change: ΔLVESV) and sex and the composite outcome of all-cause mortality, LV assist device implantation or heart transplantation was assessed. Results - At baseline, women (n=228) displayed larger electrical dyssynchrony than men (QRS area: 132±55μVs vs 123±58μVs, p=0.043) which was, even more pronounced for the QRSarea/LVEDV-ratio (0.76±0.46μVs/ml vs 0.57±0.34μVs/ml, p<0.001). After multivariable analyses female sex was associated with ΔLVESV (β 0.12, p=0.003) and a lower occurrence the composite outcome (HR 0.59 (0.42-0.85), p=0.004). A part of the female advantage regarding reverse remodeling was attributed to the larger QRSarea/LVEDV-ratio in women (25-fold change in Beta from 0.12 to 0.09). The larger QRSarea/LVEDV-ratio did not contribute to the better survival observed in women. In both volumetric responders and non-responders, female sex remained strongly associated with a lower risk of the composite outcome (adjusted HR 0.59 (0.36-0.97), p=0.036 and 0.55 (0.33-0.90), p=0.018, respectively). Conclusions - Greater electrical dyssynchrony in smaller hearts contributes in part to more reverse remodeling observed in women after CRT, but this does not explain their better long-term outcomes

    Reduction in the QRS area after cardiac resynchronization therapy is associated with survival and echocardiographic response

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    Introduction Recent studies have shown that the baseline QRS area is associated with the clinical response after cardiac resynchronization therapy (CRT). In this study, we investigated the association of QRS area reduction ( increment QRS area) after CRT with the outcome. We hypothesize that a larger increment QRS area is associated with a better survival and echocardiographic response. Methods and Results Electrocardiograms (ECG) obtained before and 2-12 months after CRT from 1299 patients in a multi-center CRT-registry were analyzed. The QRS area was calculated from vectorcardiograms that were synthesized from 12-lead ECGs. The primary endpoint was a combination of all-cause mortality, heart transplantation, and left ventricular (LV) assist device implantation. The secondary endpoint was the echocardiographic response, defined as LV end-systolic volume reduction >= of 15%. Patients with increment QRS area above the optimal cut-off value (62 mu Vs) had a lower risk of reaching the primary endpoint (hazard ratio: 0.43; confidence interval [CI] 0.33-0.56, p = 109 mu Vs, survival, and echocardiographic response were better when the increment QRS area was >= 62 mu Vs (p = 109 mu Vs, increment QRS area was the only significant predictor of survival (OR: 0.981; CI: 0.967-0.994, p = .006). Conclusion increment QRS area is an independent determinant of CRT response, especially in patients with a large baseline QRS area. Failure to achieve a large QRS area reduction with CRT is associated with a poor clinical outcome

    Are multidisciplinary neurodevelopmental profiles of children born very preterm at age 2 relevant to their long-term development?: A preliminary study

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    To identify distinctive multidisciplinary neurodevelopmental profiles of relatively healthy children born very preterm (VPT) and describe the longitudinal course of these profiles up to age 10. At 2 years of corrected age, 84 children born VPT underwent standardized testing for cognitive, language, speech, motor, behavioral, and auditory nerve function. These data were submitted to factor and cluster analysis. Sixty-one of these children underwent cognitive, language, and behavioral assessment again at age 10. Descriptive statistics were used to analyze longitudinal trajectories for each profile. Four neurodevelopmental profiles were identified at age 2. Profile 1 children (n = 22/26%) had excellent cognitive-language-motor function, normal behavioral and auditory nerve function, but showed an unexpected severe decline up to age 10. Profile 2 children (n = 16/19%) had very low behavioral function, low cognitive-language-motor function, and accelerated auditory nerve function. Their scores remained low up until age 10. Profile 3 children (n = 17/20%) had delayed auditory nerve function, low behavioral function, and slightly lower cognitive-language-motor function. They showed the most increasing trajectory. Profile 4 children (n = 29/35%) had very low cognitive-language-motor function, normal behavioral and auditory nerve function, but showed wide variation in their trajectory. Our preliminary study showed that a multidisciplinary profile-oriented approach may be important in children born VPT to improve counseling and provide targeted treatment for at risk children. High performers at age 2 may not be expected to maintain their favorable development. Behavioral problems might negatively impact language development. Delayed auditory nerve function might represent a slow start and catch-up development

    One naive T cell, multiple fates in CD8+ T cell differentiation

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    The mechanism by which the immune system produces effector and memory T cells is largely unclear. To allow a large-scale assessment of the development of single naive T cells into different subsets, we have developed a technology that introduces unique genetic tags (barcodes) into naive T cells. By comparing the barcodes present in antigen-specific effector and memory T cell populations in systemic and local infection models, at different anatomical sites, and for TCR–pMHC interactions of different avidities, we demonstrate that under all conditions tested, individual naive T cells yield both effector and memory CD8+ T cell progeny. This indicates that effector and memory fate decisions are not determined by the nature of the priming antigen-presenting cell or the time of T cell priming. Instead, for both low and high avidity T cells, individual naive T cells have multiple fates and can differentiate into effector and memory T cell subsets

    Modelling cross-reactivity and memory in the cellular adaptive immune response to influenza infection in the host

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    The cellular adaptive immune response plays a key role in resolving influenza infection. Experiments where individuals are successively infected with different strains within a short timeframe provide insight into the underlying viral dynamics and the role of a cross-reactive immune response in resolving an acute infection. We construct a mathematical model of within-host influenza viral dynamics including three possible factors which determine the strength of the cross-reactive cellular adaptive immune response: the initial naive T cell number, the avidity of the interaction between T cells and the epitopes presented by infected cells, and the epitope abundance per infected cell. Our model explains the experimentally observed shortening of a second infection when cross-reactivity is present, and shows that memory in the cellular adaptive immune response is necessary to protect against a second infection.Comment: 35 pages, 12 figure

    Old Voters on New Dimensions:Why Do Voters Vote for Pensioners' Parties? The Case of the Netherlands

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    This article analyzes the electoral support of the Dutch pensioners’ party 50Plus. Due to its open electoral system and aging population, the Netherlands is a key case to study pensioners’ parties. Our study shows that this pensioners’ party appeals to voters who are characterized by their age and their dependence on the welfare state as well as their policy positions on new lines of political conflict. In particular, their position on the new economic dimension (which concerns welfare state reform) and the new cultural dimension (which concerns immigration and EU integration) is distinct. Moreover, even when the majority of voters for this new party once supported the larger mainstream parties, they are now dissatisfied with the established politics. With rapidly aging populations across established democracies, this study is not just relevant for those studying pensioners’ parties, but rather gives an important insight into the electoral dynamics and popular support for mainstream politics, the welfare state, and social security

    Association of vectorcardiographic T-wave area with clinical and echocardiographic outcomes in cardiac resynchronization therapy

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    Aims: Data on repolarization parameters in cardiac resynchronization therapy (CRT) are scarce. We investigated the association of baseline T-wave area, with both clinical and echocardiographic outcomes of CRT in a large, multi-centre cohort of CRT recipients. Also, we evaluated the association between the baseline T-wave area and QRS area. Methods and results: In this retrospective study, 1355 consecutive CRT recipients were evaluated. Pre-implantation T-wave and QRS area were calculated from vectorcardiograms. Echocardiographic response was defined as a reduction of ≥15% in left ventricular end-systolic volume between 3 and 12 months after implantation. The clinical outcome was a combination of all-cause mortality, heart transplantation, and left ventricular assist device implantation. Left ventricular end-systolic volume reduction was largest in patients with QRS area ≥ 109 μVs and T-wave area ≥ 66 μVs compared with QRS area ≥ 109 μVs and T-wave area < 66 μVs (P = 0.004), QRS area < 109 μVs and T-wave area ≥ 66 μVs (P < 0.001) and QRS area < 109 μVs and T-wave area < 66 μVs (P < 0.001). Event-free survival rate was higher in the subgroup of patients with QRS area ≥ 109 μVs and T-wave area ≥ 66 μVs (n = 616, P < 0.001) and QRS area ≥ 109 μVs and T-wave area < 66 μVs (n = 100, P < 0.001) than the other subgroups. In the multivariate analysis, T-wave area remained associated with echocardiographic response (P = 0.008), but not with the clinical outcome (P = 0.143), when QRS area was included in the model. Conclusion: Baseline T-wave area has a significant association with both clinical and echocardiographic outcomes after CRT. The association of T-wave area with echocardiographic response is independent from QRS area; the association with clinical outcome, however, is not
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