Developing a Grounded Theory Model on Collaboration in Learning

The purpose of this research is to develop a grounded theory model to explain the factors influencing collaborative learning in higher education, the role of technology in facilitating collaboration, and the outcome of collaboration. We assigned 28 participants to small groups to work on course-related questions; half of the groups were face-to-face groups and the other half groups were collaborating in a simulated virtual environment with the aid of information technology. Interview data was collected and analyzed following the grounded theory approach. Congruent with distributed cognition theories, the results of our study suggest that both social and technological factors were important and interlocking. We also discussed the importance of designing learning technologies that have strong social and communications features

A Novel Inflammation-Based Risk Score Predicts Mortality in Acute Type A Aortic Dissection Surgery: The Additive Anti-inflammatory Action for Aortopathy and Arteriopathy Score

Objective: To develop an inflammation-based risk stratification tool for operative mortality in patients with acute type A aortic dissection. Methods: Between January 1, 2016 and December 31, 2021, 3124 patients from Beijing Anzhen Hospital were included for derivation, 571 patients from the same hospital were included for internal validation, and 1319 patients from other 12 hospitals were included for external validation. The primary outcome was operative mortality according to the Society of Thoracic Surgeons criteria. Least absolute shrinkage and selection operator regression were used to identify clinical risk factors. A model was developed using different machine learning algorithms. The performance of the model was determined using the area under the receiver operating characteristic curve (AUC) for discrimination, calibration curves, and Brier score for calibration. The final model (5A score) was tested with respect to the existing clinical scores. Results: Extreme gradient boosting was selected for model training (5A score) using 12 variables for prediction—the ratio of platelet to leukocyte count, creatinine level, age, hemoglobin level, prior cardiac surgery, extent of dissection extension, cerebral perfusion, aortic regurgitation, sex, pericardial effusion, shock, and coronary perfusion—which yields the highest AUC (0.873 [95% confidence interval (CI) 0.845-0.901]). The AUC of 5A score was 0.875 (95% CI 0.814-0.936), 0.845 (95% CI 0.811-0.878), and 0.852 (95% CI 0.821-0.883) in the internal, external, and total cohort, respectively, which outperformed the best existing risk score (German Registry for Acute Type A Aortic Dissection score AUC 0.709 [95% CI 0.669-0.749]). Conclusion: The 5A score is a novel, internally and externally validated inflammation-based tool for risk stratification of patients before surgical repair, potentially advancing individualized treatment. Trial Registration: clinicaltrials.gov Identifier: NCT0491810

21st Century Cardio-Oncology

Cardiotoxicity is a well-established complication of oncology therapies. Cardiomyopathy resulting from anthracyclines is a classic example. In the past decade, an explosion of novel cancer therapies, often targeted and more specific than conventional therapies, has revolutionized oncology therapy and dramatically changed cancer prognosis. However, some of these therapies have introduced an assortment of cardiovascular (CV) complications. At times, these devastating outcomes have only become apparent after drug approval and have limited the use of potent therapies. There is a growing need for better testing platforms, both for CV toxicity screening and for elucidating mechanisms of cardiotoxicities of approved cancer therapies. This review discusses the utility of available nonclinical models (in vitro, in vivo, and in silico) and highlights recent advancements in modalities like human stem cell-derived cardiomyocytes for developing more comprehensive cardiotoxicity testing and new means of cardioprotection with targeted anticancer therapies

Aged Human Multipotent Mesenchymal Stromal Cells Can Be Rejuvenated by Neuron-Derived Neurotrophic Factor and Improve Heart Function After Injury

Reduced regenerative capacity of aged stem cells hampers the benefits of autologous cell therapy for cardiac regeneration. This study investigated whether neuron-derived neurotrophic factor (NDNF) could rejuvenate aged human bone marrow (hBM)- multipotent mesenchymal stromal cells (MSCs) and whether the rejuvenated hBM-MSCs could improve cardiac repair after ischemic injury. Over-expression of NDNF in old hBM-MSCs decreased cell senescence and apoptosis. Engraftment of NDNF over-expressing old hBM-MSCs into the ischemic area of mouse hearts resulted in improved cardiac function after myocardial infarction, while promoting implanted stem cell survival. Our findings suggest NDNF could be a new factor to rejuvenate aged stem cells and improve their capability to repair the aged heart after injury

Left Ventricular Diastolic Function Assessment Using the Timing of Mitral Annular and Transmitral Flow Velocities

Background and aims: Evaluation of left ventricular (LV) diastolic function plays an important role in clinical echocardiography. The relationship between mitral annular velocities from tissue Doppler imaging (TDI) (E′ and A′) and mitral inflow velocities (E and A) from Doppler echocardiography (DE) provide additional information about LV filling and diastolic function. The aims of this study are to i) assess the time differences between peak E and peak E′, peak A and peak A′, peak Ar and peak A, and ii) examine the effects of age and gender on these time intervals parameters in normal subjects. Methods: A total of 117 healthy subjects (age ranging from 22- to 78-years-old) were recruited for a standard of echocardiogram (ECHO). During early diastole, the time intervals from the peak of R-wave on the ECG to the peak of E-wave (R-pE), to the peak of E wave to peak of E′-wave (R-pE′) were measured. During late diastole, the time intervals from the onset of P-wave on the ECG to the peak A-wave (P-pA), to the peak Ar-wave on the pulmonary valve flow (P-pAr), to the peak A′-wave (P-pA′) were measured. Early-diastolic temporal discordance (EDTD) and late-diastolic temporal discordance (LDTD) were calculated as the differences between (R-pE) and (R-pE′), and (P-pA) and (P-pA′), respectively. Results: The mean EDTD and LDTD were 28.7 ± 10.6 ms and 21.2 ± 15.9 ms, respectively. Similarly, the mean time difference [(P-pA) - (P-pAr)] was 21.5 ± 14.1 ms. EDTD was not associated with age (r=0.15, p =NS), while LDTD was inversely correlated with age (r=-0.65, p <0.01). No significant differences were found for both EDTD and LDTD between genders. Conclusion: EDTD and LDTD, the temporal discordances between mitral annulus motion and trans-mitral flow, embody one of the earliest events at early- and late-diastole. Age is not associated with EDTD, but is accompanied by a decline in LDTD. With respect to gender, both EDTD and LDTD are not influenced