1,138 research outputs found
Modulation of three-dimensional structure and research of folding-analoges of AMB A 6 allergen of Ambrosia artemisiifolia
Amb A 6 allergen of Ambrosia artemisiifolia is a ragweed allergen (a principle cause
of late summer hayfever in North America and Europe) (Hiller et al. 1998). The
weed has recently become spreading as a neophyte in Europe, while climate change
may also affect the growth of the plant and additionally may also influence pollen
allergenicity (Kelish et al. 2014). In Ukraine, the number of diseases caused by
this allergen has recently increases. The three-dimensional structure of Amb A 6
allergen is undescribed.
The aim of our study was to modulate of three-dimensional structure and search
of folding-analoges of AMB A 6 allergen of A. artemisiifolia
Hippocampal subfields and limbic white matter jointly predict learning rate in older adults
First published online: 04 December 2019Age-related memory impairments have been linked to differences in structural brain parameters, including cerebral white matter (WM) microstructure and hippocampal (HC) volume, but their combined influences are rarely investigated. In a population-based sample of 337 older participants aged 61-82 years (Mage = 69.66, SDage = 3.92 years), we modeled the independent and joint effects of limbic WM microstructure and HC subfield volumes on verbal learning. Participants completed a verbal learning task of recall over five repeated trials and underwent magnetic resonance imaging (MRI), including structural and diffusion scans. We segmented three HC subregions on high-resolution MRI data and sampled mean fractional anisotropy (FA) from bilateral limbic WM tracts identified via deterministic fiber tractography. Using structural equation modeling, we evaluated the associations between learning rate and latent factors representing FA sampled from limbic WM tracts, and HC subfield volumes, and their latent interaction. Results showed limbic WM and the interaction of HC and WM-but not HC volume alone-predicted verbal learning rates. Model decomposition revealed HC volume is only positively associated with learning rate in individuals with higher WM anisotropy. We conclude that the structural characteristics of limbic WM regions and HC volume jointly contribute to verbal learning in older adults
Interpersonal affect in groupwork: A comparative case study of two small groups with contrasting group dynamics outcomes
Teamwork capabilities are essential for 21st century life, with groupwork emerging as a fruitful context to develop these skills. Case studies that explore interpersonal affect dynamics in authentic higher education groupwork settings can highlight collaborative skills development needs. This comparative case-study traced the sociodynamic evolution of two groups of first-year university students to investigate the high collaborative variance outcomes of the two groups, which reported starkly contrasting group dynamics (negative and dysfunctional or positive and collaborative). Mixed-methods (video-recorded observations of five groupwork labs over one semester, and group interviews) provided interpersonal affect data as real-time visible behaviours, and the felt experiences and perceptions of participants. The study traced interpersonal affect dynamics in the natural fluctuation of not just task-focused (on-task), but also explicitly relational (off-task) interactions, which revealed their function in both task participation and group dynamics. Findings illustrate visible interpersonal affect behaviours that manifested and evolved over time as interactive patterns, and group dynamics outcomes. Fine-grained analysis of interactions unveiled interpersonal affect as a collective, evolving process, and the mechanism through which one group started and stayed highly positive and collaborative over the semester. The other group showed a tendency towards splitting to undertake tasks early, leading to low group-level interpersonal attentiveness, and over time, subgroups emerged through interactions both off-task and on-task. The study made visible the pervasive nature of interpersonal affect as enacted through seemingly inconsequential everyday behaviours that supported the relational and task-based needs of groupwork, and those behaviours which impeded collaboration
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Magnetic Resonance Imaging Pilot Study of Intravenous Glyburide in Traumatic Brain Injury.
Pre-clinical studies of traumatic brain injury (TBI) show that glyburide reduces edema and hemorrhagic progression of contusions. We conducted a small Phase II, three-institution, randomized placebo-controlled trial of subjects with TBI to assess the safety and efficacy of intravenous (IV) glyburide. Twenty-eight subjects were randomized and underwent a 72-h infusion of IV glyburide or placebo, beginning within 10 h of trauma. Of the 28 subjects, 25 had Glasgow Coma Scale (GCS) scores of 6-10, and 14 had contusions. There were no differences in adverse events (AEs) or severe adverse events (ASEs) between groups. The magnetic resonance imaging (MRI) percent change at 72-168 h from screening/baseline was compared between the glyburide and placebo groups. Analysis of contusions (7 per group) showed that lesion volumes (hemorrhage plus edema) increased 1036% with placebo versus 136% with glyburide (p = 0.15), and that hemorrhage volumes increased 11.6% with placebo but decreased 29.6% with glyburide (p = 0.62). Three diffusion MRI measures of edema were quantified: mean diffusivity (MD), free water (FW), and tissue MD (MDt), corresponding to overall, extracellular, and intracellular water, respectively. The percent change with time for each measure was compared in lesions (n = 14) versus uninjured white matter (n = 24) in subjects receiving placebo (n = 20) or glyburide (n = 18). For placebo, the percent change in lesions for all three measures was significantly different compared with uninjured white matter (analysis of variance [ANOVA], p < 0.02), consistent with worsening of edema in untreated contusions. In contrast, for glyburide, the percent change in lesions for all three measures was not significantly different compared with uninjured white matter. Further study of IV glyburide in contusion TBI is warranted
High Current CD4+ T cell count predicts suboptimal adherence to antiretroviral therapy
Date of Acceptance: 30/09/2015 Funding: A.O.P. is financially supported by the Dutch AIDS Fonds (http://www.aidsfonds.nl/), grant nrs. 2011020 and 2012025. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD
Estimation of Fiber Orientations Using Neighborhood Information
Data from diffusion magnetic resonance imaging (dMRI) can be used to
reconstruct fiber tracts, for example, in muscle and white matter. Estimation
of fiber orientations (FOs) is a crucial step in the reconstruction process and
these estimates can be corrupted by noise. In this paper, a new method called
Fiber Orientation Reconstruction using Neighborhood Information (FORNI) is
described and shown to reduce the effects of noise and improve FO estimation
performance by incorporating spatial consistency. FORNI uses a fixed tensor
basis to model the diffusion weighted signals, which has the advantage of
providing an explicit relationship between the basis vectors and the FOs. FO
spatial coherence is encouraged using weighted l1-norm regularization terms,
which contain the interaction of directional information between neighbor
voxels. Data fidelity is encouraged using a squared error between the observed
and reconstructed diffusion weighted signals. After appropriate weighting of
these competing objectives, the resulting objective function is minimized using
a block coordinate descent algorithm, and a straightforward parallelization
strategy is used to speed up processing. Experiments were performed on a
digital crossing phantom, ex vivo tongue dMRI data, and in vivo brain dMRI data
for both qualitative and quantitative evaluation. The results demonstrate that
FORNI improves the quality of FO estimation over other state of the art
algorithms.Comment: Journal paper accepted in Medical Image Analysis. 35 pages and 16
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Comparison of droplet digital PCR and seminested real-time PCR for quantification of cell-associated HIV-1 RNA
Cell-associated (CA) HIV-1 RNA is considered a potential marker for assessment of viral reservoir dynamics and antiretroviral therapy (ART) response in HIV-infected patients. Recent studies employed sensitive seminested real-time quantitative (q)PCR to quantify CA HIV-1 RNA. Digital PCR has been recently described as an alternative PCR-based technique for absolute quantification with higher accuracy compared to qPCR. Here, a comparison was made between the droplet digital PCR (ddPCR) and the seminested qPCR for quantification of unspliced (us) and multiply spliced (ms) CA HIV-1 RNA. Synthetic RNA standards and CA HIV-1 RNA from infected patients on and off ART (N = 34) were quantified with both methods. Correlations were observed between the methods both for serially diluted synthetic standards (usRNA: R2 = 0.97, msRNA: R2 = 0.92) and patient-derived samples (usRNA: R2 = 0.51, msRNA: R2 = 0.87). Seminested qPCR showed better quantitative linearity, accuracy and sensitivity in the quantification of synthetic standards than ddPCR, especially in the lower quantification ranges. Both methods demonstrated equally high detection rate of usRNA in patient samples on and off ART (91%), whereas ddPCR detected msRNA in larger proportion of samples from ART-treated patients (p = 0.13). We observed an average agreement between the methods for usRNA quantification in patient samples, albeit with a large standard deviation (bias = 0.05±0.75 log10). However, a bias of 0.94±0.36 log10 was observed for msRNA. No-template controls were consistently negative in the seminested qPCR, but yielded a positive ddPCR signal for some wells. Therefore, the false positive signals may have affected the detection power of ddPCR in this study. Digital PCR is promising for HIV nucleic acid quantification, but the false positive signals need further attention. Quantitative assays for CA HIV RNA have the potential to improve monitoring of patients on ART and to be used in clinical studies aimed at HIV eradication, but should be cross-validated by multiple laboratories prior to wider use
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