Optimising Recycling Processes for Polyimine-Based Vitrimer Carbon Fibre-Reinforced Composites: A Comparative Study on Reinforcement Recovery and Material Properties.

We investigated the recycling process of carbon fibre-reinforced polyimine vitrimer composites and compared composites made from virgin and recycled fibres. The vitrimer matrix consisted of a two-component polyimine-type vitrimer system, and as reinforcing materials, we used nonwoven felt and unidirectional carbon fibre. Various diethylenetriamine (DETA) and xylene solvent ratios were examined to find the optimal dissolution conditions. The 20:80 DETA-xylene ratio provided efficient dissolution, and the elevated temperature (80 °C) significantly accelerated the process. Scaling up to larger composite structures was demonstrated. Scanning electron microscopy (SEM) confirmed effective matrix removal, with minimal residue on carbon fibre surfaces and good adhesion in recycled composites. The recycled nonwoven composite exhibited a decreased glass transition temperature due to the residual solvents in the matrix, while the UD composite showed a slight increase. Dynamic mechanical analysis on the recycled composite showed an increased storage modulus for nonwoven composites at room temperature and greater resistance to deformation at elevated temperatures for the UD composites. Interlaminar shear tests indicated slightly reduced adhesion strength in the reprocessed composites. Overall, this study demonstrates the feasibility of recycling vitrimer composites, emphasising the need for further optimisation to ensure environmental and economic sustainability while mitigating residual solvent and matrix effects.

Nox2 and Nox4 influence neonatal c-kit(+) cardiac precursor cell status and differentiation.

Redox status has emerged as critical in modulating stemness and lineage commitment in several precursor cell types. However, a role for redox genes, specifically NADPH oxidases (Nox), in cardiac precursor cells (CPCs) has not been established. We tested whether CPCs marked by type III receptor tyrosine kinase c-kit (c-kit(+)) exhibit a unique NADPH oxidase signature that confers precursor status and whether alterations in this profile are functionally linked to changes in lineage specification. Dihydroethidium (DHE) microfluorography indicated reduced basal reactive oxygen species (ROS) formation within early postnatal c-kit(+) CPCs. Real-time quantitative PCR revealed downregulation of ROS generator Nox2 and its subunit p67(phox) in c-kit(+) CPCs under basal conditions but upregulation of Nox2 and Nox4 over the course of differentiation. Adenoviral silencing of Nox2 and Nox4 increased expression of CPC markers c-kit and Flk-1 and blunted smooth and cardiac muscle differentiation, respectively, while overexpression of Nox2 and Nox4 significantly reduced c-kit expression. These changes were accompanied by altered expression of transcription factors regulating cardiac lineage commitment, Gata6 and Gata4, and cytokine transforming growth factor (TGF)-ß1. Similar to other precursor cell types, RT(2)Profiler PCR Arrays revealed that c-kit(+) CPCs also exhibit enhanced antioxidant capacity at the mRNA level. In conclusion, we report that c-kit(+) CPCs demonstrate reduced Nox2 expression and ROS levels and that increases in Nox2 and Nox4 influence their differentiation into mature cells. We speculate that ROS generators Nox2 and Nox4, along with the antioxidant genes identified by PCR Arrays, may be novel targets in CPCs that could prove useful in cell-based therapy of the heart.

Computer use among community-based primary care physician preceptors.

PURPOSE: Use of the Internet to access biomedical information in patient care has important implications in medical education. Little is known about how community-based clinical teachers use computers in their offices and what factors, such as age, may influence use. METHOD: A total of 178 active community-based primary care preceptors were mailed a 15-item questionnaire about their computer equipment; Internet use; and specific applications in patient care, patients' education, medical students' or residents' education, or accessing other clinical and/or research information. Data analysis used descriptive statistics, chi-square for comparisons of categorical data and analysis of variance (ANOVA) mixed model for comparisons of continuous variables. All tests were two-tailed with alpha set at.05 to determine statistical significance. RESULTS: In all, 129 preceptors responded (73%). Office computer availability was high (92%). The Internet as a clinical information resource was used most frequently (98%) and MD Consult and Medline-EBM were used less frequently (20% and 21%, respectively). No statistical differences were found in routine use by age of preceptor; frequency of use did differ. Preceptors 60 years or older were four times more likely to use the Internet to assist in students' and residents' education (p =.02) and at least twice as likely to use full text Medline articles for patient care decisions (p =.05) than their younger colleagues. Decreased computer use was related to lack of time (45%) or other logistical reasons (40%), such as the computer's distance from the patient care areas or slow connections. CONCLUSIONS: Rates of computer access and Internet connectivity were high among community-based preceptors of all ages. Uses of specific online clinical and/or educational resources varied by preceptors' age with more rather than less use among older preceptors, an unexpected finding.

A collaborative model for supporting community-based interdisciplinary education.

Development and support of community-based, interdisciplinary ambulatory medical education has achieved high priority due to on-site capacity and the unique educational experiences community sites contribute to the educational program. The authors describe the collaborative model their school developed and implemented in 2000 to integrate institution- and community-based interdisciplinary education through a centralized office, the strengths and challenges faced in applying it, the educational outcomes that are being tracked to evaluate its effectiveness, and estimates of funds needed to ensure its success. Core funding of $180,000 is available annually for a centralized office, the keystone of the model described here. With this funding, the office has (1) addressed recruitment, retention, and quality of educators for UME; (2) promoted innovation in education, evaluation, and research; (3) supported development of a comprehensive curriculum for medical school education; and (4) monitored the effectiveness of community-based education programs by tracking product yield and cost estimates needed to generate these programs. The model's Teaching and Learning Database contains information about more than 1,500 educational placements at 165 ambulatory teaching sites (80% in northern New England) involving 320 active preceptors. The centralized office facilitated 36 site visits, 22% of which were interdisciplinary, involving 122 preceptors. A total of 98 follow-up requests by community-based preceptors were fulfilled in 2000. The current submission-to-funding ratio for educational grants is 56%. Costs per educational activity have ranged from $811.50 to $1,938, with costs per preceptor ranging from $101.40 to $217.82. Cost per product (grants, manuscripts, presentations) in research and academic scholarship activities was $2,492. The model allows the medical school to balance institutional and departmental support for its educational programs, and to better position itself for the ongoing changes in the health care system.