144 research outputs found
Cognitive demands of face monitoring: Evidence for visuospatial overload
Young children perform difficult communication tasks better face to face than when they cannot see one another (e.g., Doherty-Sneddon & Kent, 1996). However, in recent studies, it was found that children aged 6 and 10 years, describing abstract shapes, showed evidence of face-to-face interference rather than facilitation. For some communication tasks, access to visual signals (such as facial expression and eye gaze) may hinder rather than help childrenās communication. In new research we have pursued this interference effect. Five studies are described with adults and 10- and 6-year-old participants. It was found that looking at a face interfered with childrenās abilities to listen to descriptions of abstract shapes. Children also performed visuospatial memory tasks worse when they looked at someoneās face prior to responding than when they looked at a visuospatial pattern or at the floor. It was concluded that performance on certain tasks was hindered by monitoring another personās face. It is suggested that processing of visual communication signals shares certain processing resources with the processing of other visuospatial information
Temperature and magnetic field dependence of the lattice constant in spin-Peierls cuprate CuGeO_3 studied by capacitance dilatometry in fields up to 16 Tesla
We present high resolution measurements of the thermal expansion coefficient
and the magnetostriction along the a-axis of CuGeO_3 in magnetic fields up to
16 Tesla. From the pronounced anomalies of the lattice constant a occurring for
both temperature and field induced phase transitions clear structural
differences between the uniform, dimerized, and incommensurate phases are
established. A precise field temperature phase diagram is derived and compared
in detail with existing theories. Although there is a fair agreement with the
calculations within the Cross Fisher theory, some significant and systematic
deviations are present. In addition, our data yield a high resolution
measurement of the field and temperature dependence of the spontaneous strain
scaling with the spin-Peierls order parameter. Both the zero temperature values
as well as the critical behavior of the order parameter are nearly field
independent in the dimerized phase. A spontaneous strain is also found in the
incommensurate high field phase, which is significantly smaller and shows a
different critical behavior than that in the low field phase. The analysis of
the temperature dependence of the spontaneous strain yields a pronounced field
dependence within the dimerized phase, whereas the temperature dependence of
the incommensurate lattice modulation compares well with that of the
dimerization in zero magnetic field.Comment: 25 pages, 15 Figs., to appear in Phys. Rev. B55 (Vol.5
PDGF-RĪ± gene expression predicts proliferation, but PDGF-A suppresses transdifferentiation of neonatal mouse lung myofibroblasts
<p>Abstract</p> <p>Background</p> <p>Platelet-derived growth factor A (PDGF-A) signals solely through PDGF-RĪ±, and is required for fibroblast proliferation and transdifferentiation (fibroblast to myofibroblast conversion) during alveolar development, because <it>pdgfa</it>-null mice lack both myofibroblasts and alveoli. However, these PDGF-A-mediated mechanisms remain incompletely defined. At postnatal days 4 and 12 (P4 and P12), using mouse lung fibroblasts, we examined (a) how PDGF-RĪ± correlates with ki67 (proliferation marker) or alpha-smooth muscle actin (Ī±SMA, myofibroblast marker) expression, and (b) whether PDGF-A directly affects Ī±SMA or modifies stimulation by transforming growth factor beta (TGFĪ²).</p> <p>Methods</p> <p>Using flow cytometry we examined PDGF-RĪ±, Ī±SMA and Ki67 in mice which express green fluorescent protein (GFP) as a marker for PDGF-RĪ± expression. Using real-time RT-PCR we quantified Ī±SMA mRNA in cultured Mlg neonatal mouse lung fibroblasts after treatment with PDGF-A, and/or TGFĪ².</p> <p>Results</p> <p>The intensity of GFP-fluorescence enabled us to distinguish three groups of fibroblasts which exhibited absent, lower, or higher levels of PDGF-RĪ±. At P4, more of the higher than lower PDGF-RĪ± + fibroblasts contained Ki67 (Ki67+), and Ki67+ fibroblasts predominated in the Ī±SMA + but not the Ī±SMA- population. By P12, Ki67+ fibroblasts comprised a minority in both the PDGF-RĪ± + and Ī±SMA+ populations. At P4, most Ki67+ fibroblasts were PDGF-RĪ± + and Ī±SMA- whereas at P12, most Ki67+ fibroblasts were PDGF-RĪ±- and Ī±SMA-. More of the PDGF-RĪ± + than - fibroblasts contained Ī±SMA at both P4 and P12. In the lung, proximate Ī±SMA was more abundant around nuclei in cells expressing high than low levels of PDGF-RĪ± at both P4 and P12. Nuclear SMAD 2/3 declined from P4 to P12 in PDGF-RĪ±-, but not in PDGF-RĪ± + cells. In Mlg fibroblasts, Ī±SMA mRNA increased after exposure to TGFĪ², but declined after treatment with PDGF-A.</p> <p>Conclusion</p> <p>During both septal eruption (P4) and elongation (P12), alveolar PDGF-RĪ± may enhance the propensity of fibroblasts to transdifferentiate rather than directly stimulate Ī±SMA, which preferentially localizes to non-proliferating fibroblasts. In accordance, PDGF-RĪ± more dominantly influences fibroblast proliferation at P4 than at P12. In the lung, TGFĪ² may overshadow the antagonistic effects of PDGF-A/PDGF-RĪ± signaling, enhancing Ī±SMA-abundance in PDGF-RĪ±-expressing fibroblasts.</p
Inflammatory pathway analytes predicting rapid cognitive decline in MCI stage of Alzheimerās disease
Objective
To determine the inflammatory analytes that predict clinical progression and evaluate their performance against biomarkers of neurodegeneration.
Methods
A longitudinal study of MCIāAD patients in a Discovery cohort over 15 months, with replication in the Alzheimerās Disease Neuroimaging Initiative (ADNI) MCI cohort over 36 months. Fiftyāthree inflammatory analytes were measured in the CSF and plasma with a RBM multiplex analyte platform. Inflammatory analytes that predict clinical progression on Clinical Dementia Rating ScaleāSum of Boxes (CDRāSB) and Mini Mental State Exam scores were assessed in multivariate regression models. To provide context, key analyte results in ADNI were compared against biomarkers of neurodegeneration, hippocampal volume, and CSF neurofilament light (NfL), in receiver operating characteristic (ROC) analyses evaluating highest quartile of CDRāSB change over two years (ā„3 points).
Results
Cerebrospinal fluid inflammatory analytes in relation to cognitive decline were best described by gene ontology terms, natural killer cell chemotaxis, and endothelial cell apoptotic process and in plasma, extracellular matrix organization, blood coagulation, and fibrin clot formation described the analytes. CSF CCL2 was most robust in predicting rate of cognitive change and analytes that correlated to CCL2 suggest ILā10 pathway dysregulation. The ROC curves for ā„3 points change in CDRāSB over 2 years when comparing baseline hippocampal volume, CSF NfL, and CCL2 were not significantly different.
Interpretation
Baseline levels of immune cell chemotactic cytokine CCL2 in the CSF and ILā10 pathway dysregulation impact longitudinal cognitive and functional decline in MCIāAD. CCL2ās utility appears comparable to biomarkers of neurodegeneration in predicting rapid decline
Do intoxicated witnesses produce poor facial composite images?
The effect of alcohol intoxication on witness memory and performance has been the subject of research for some time, however, whether intoxication affects facial composite construction has not been investigated. Intoxication was predicted to adversely affect facial composite construction. Thirty-two participants were allocated to one of four beverage conditions consisting of factorial combinations of alcohol or placebo at face encoding, and later construction. Participants viewed a video of a target person and constructed a composite of this target the following day. The resulting images were presented as a full face composite, or a part face consisting of either internal or external facial features to a second sample of participants who provided likeness ratings as a measure of facial composite quality. Intoxication at face encoding had a detrimental impact on the quality of facial composites produced the following day, suggesting that alcohol impaired the encoding of the target faces. The common finding that external compared to internal features are more accurately represented was demonstrated, even following alcohol at encoding. This finding was moderated by alcohol and target face gender such that alcohol at face encoding resulted in reduced likeness of external features for male composite faces only. Moderate alcohol intoxication impairs the quality of facial composites, adding to existing literature demonstrating little effect of alcohol on line-up studies. The impact of intoxication on face perception mechanisms, and the apparent narrowing of processing to external face areas such as hair, is discussed in the context of alcohol myopia theory
Preoperative chemoradiation with capecitabine, irinotecan and cetuximab in rectal cancer: significance of pre-treatment and post-resection RAS mutations
Background: The influence of EGFR pathway mutations on cetuximab-containing rectal cancer preoperative chemoradiation (CRT) is uncertain. Methods: In a prospective phase II trial (EXCITE), patients with magnetic resonance imaging (MRI)-defined non-metastatic rectal adenocarinoma threatening/involving the surgical resection plane received pelvic radiotherapy with concurrent capecitabine, irinotecan and cetuximab. Resection was recommended 8 weeks later. The primary endpoint was histopathologically clear (R0) resection margin. Pre-planned retrospective DNA pyrosequencing (PS) and next generation sequencing (NGS) of KRAS, NRAS, PIK3CA and BRAF was performed on the pre-treatment biopsy and resected specimen. Results: Eighty-two patients were recruited and 76 underwent surgery, with R0 resection in 67 (82%, 90%CI: 73ā88%) (four patients with clinical complete response declined surgery). Twentyāfour patients (30%) had an excellent clinical or pathological response (ECPR). Using NGS 24 (46%) of 52 matched biopsies/resections were discrepant: ten patients (19%) gained 13 new resection mutations compared to biopsy (12 KRAS, one PIK3CA) and 18 (35%) lost 22 mutations (15 KRAS, 7 PIK3CA). Tumours only ever testing RAS wild-type had significantly greater ECPR than tumours with either biopsy or resection RAS mutations (14/29 [48%] vs 10/51 [20%], P=0.008), with a trend towards increased overall survival (HR 0.23, 95% CI 0.05ā1.03, P=0.055). Conclusions: This regimen was feasible and the primary study endpoint was met. For the first time using pre-operative rectal CRT, emergence of clinically important new resection mutations is described, likely reflecting intratumoural heterogeneity manifesting either as treatment-driven selective clonal expansion or a geographical biopsy sampling miss
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