Interfacial Layers between Ion and Water Detected by Terahertz Spectroscopy

Dynamic fluctuations in hydrogen-bond network of water occur from femto- to nano-second timescale and provides insights into structural/dynamical aspects of water at ion-water interfaces. Employing terahertz spectroscopy assisted with molecular dynamics simulations, we study aqueous chloride solutions of five monovalent cations, namely, Li, Na, K, Rb and Cs. We show that ions modify the behavior of surrounding water molecules and form interfacial layers of water around them with physical properties distinct from that of bulk water. Small cations with high charge densities influence the kinetics of water well beyond the first solvation shell. At terahertz frequencies, we observe an emergence of fast relaxation processes of water with their magnitude following the ionic order Cs>Rb>K>Na>Li, revealing an enhanced population density of weakly coordinated water at ion-water interface. The results shed light on the structure breaking tendency of monovalent cations and provide insights into the properties of ionic solutions at the molecular level

Fretting Fatigue Damage Nucleation and Propagation Lifetime Using a Central Point Movement of Power Spectral Density

This paper presents a new perception in evaluating fretting fatigue damage nucleation and propagation lifetime under periodically forced circulation. A new approach, which is proposed in this paper, is to measure the change of the central point of power spectral density (CP-PSD) in different structural stiffness degradation stages. A notable aspect of this study lies in the combination between vibration amplitude and forced frequency of the fatigue-causing factors in beam structures. Additionally, it is found that randomization of the first phase from 0 to 2π yields more accurate modelling of the fatigue phenomenon. Results show that the CP-PSD parameter is significantly more sensitive compared to the regularly damage-evaluating parameters such as natural frequency, eigenvalues, or stress value. This reflects different levels of fatigue cycle effect on the structure in the experiment. At the same time, CP-PSD also categorizes the degradation level on different points on the structure under the periodically forced circulation. In addition, this paper also quantifies the relation between the changes of CP-PSD and each fatigue state. Results of this research will be a reference source to evaluate the lifespan of the structure by experimental methods

Transforming medical education to strengthen the health professional training in Viet Nam: A case study

The competency-based undergraduate curriculum reform at the University of Medicine and Pharmacy at Ho Chi Minh City, Faculty of Medicine (UMP-FM) is detailed and reviewed in reference to the instructional and institutional reforms, and enabling actions recommended by the Lancet 2010 Commission for Health Professional Education. Key objectives are to: revise the overall 6-year curriculum to be more integrated and competency-based; reinforce students’ knowledge application, problem-solving, clinical competence, self-directed learning and soft skills; develop a comprehensive and performance-based student assessment programme; and establish a comprehensive quality monitoring programme to facilitate changes and improvements. New features include early introduction to the practice of medicine, family- and community-based medicine, professionalism, interprofessional education, electives experiences, and a scholarly project. Institutional reform introduces a faculty development programme, joint planning mechanism, a “culture of critical inquiry”, and a transparent faculty reward system. Lessons learnt from the curriculum reform at UMP-FM could be helpful to medical schools from low- and middle-income countries considering transitioning from a traditional to a competency-based curriculum