Hyper-sensitive piezophotovoltaic effects in ferroelectric nanocylinders

Author name used in this publication: C. H. Woo2009-2010 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Theoretical studies of the local structures and EPR parameters for Cu2+^{2+} center in Cd2_{2}(NH4_{4})2_{2}(SO4_{4})3_{3} single crystal

The electron paramagnetic resonance (EPR) parameters ($g$ factors $g_{i}$ and the hyperfine structure constants ${{A}}_{{i}}$, ${i} = {x}, {y}, {z}$) are interpreted by using the perturbation formulae for a $3{d}^{9}$ ion in rhombically ({D}$_{2h}$) elongated octahedra. In the calculated formulae, the crystal field parameters are set up from the superposition model, and the contribution to the EPR parameters from the admixture of $d$-orbitals in the ground state wave function of the Cu$^{2+}$ ion was taken into account. Based on the calculation, local structural parameters of the impurity Cu$^{2+}$ center in Cd$_{2}$(NH$_{4}$)$_{2}$(SO$_{4}$)$_{3}$ (CAS) crystal were obtained (i.e., ${R}_{{x}}\approx 2.05$ {\AA}, ${R}_{{y}} \approx 1.91$ {\AA}, ${R}_{{z}} \approx 2.32$ {\AA}). The theoretical EPR parameters based on the above Cu$^{2+}$-O$^{2-}$ bond lengths in CAS crystal show a good agreement with the observed values. The results are discussed.Comment: 5 page

Controlling dielectric and pyroelectric properties of compositionally graded ferroelectric rods by an applied pressure

Author name used in this publication: C. H. Woo2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Oral treatment with herbal formula B307 alleviates skeletal muscle atrophy from hind-limb unloading

PosterINTRODUCTION: Muscle atrophy can result from physical inactivity, chronic bedrest, and ageing. Traditional Chinese herbal formula B307 is a health supplement with multiple potential protective functions of organs. We investigated the effects of herbal formula B307 on muscle atrophy using the hind-limb unloading (HU) model in mice …published_or_final_versio

Arresting rampant dental caries with silver diamine fluoride in a young teenager suffering from chronic oral graft versus host disease post-bone marrow transplantation: a case report

BACKGROUND: Rampant caries is an advanced and severe dental disease that affects multiple teeth. This case describes the management of rampant caries in a young teenager suffering from chronic oral graft versus host disease after allogeneic bone marrow transplantation. CASE PRESENTATION: A 14-year-old Chinese boy suffering from beta-thalassemia major was referred to the dental clinic for the management of rampant dental caries. An oral examination revealed pale conjunctiva, bruising of lips, and depapillation of tongue indicating an underlying condition of anemia. The poor oral condition due to topical and systemic immunosuppressants was seriously aggravated, and rampant caries developed rapidly, affecting all newly erupted, permanent teeth. The teeth were hypersensitive and halitosis was apparent. Strategies for oral health education and diet modification were given to the patient. Xylitol chewing gum was used to stimulate saliva flow to promote remineralization of teeth. Silver diamine fluoride was topically applied to arrest rampant caries and to relieve pain from hypersensitivity. Carious teeth with pulpal involvement were endodontically treated. Stainless steel crowns were provided on molars to restore chewing function, and polycarbonate crowns were placed on premolars, upper canines and incisors. CONCLUSION: This case report demonstrates success in treating a young teenager with severe rampant dental decay by contemporary caries control and preventive strategy.published_or_final_versio

Oral Health Status of Chinese Paediatric and Adolescent Oncology Patients with Chemotherapy in Hong Kong: a Pilot Study

Aim: To study the oral health status of Chinese children and adolescents undergoing chemotherapy in Hong Kong. Method: All Chinese children and adolescent oncology patients aged 18 or below attending the Children's Centre for Cancer and Blood Disease at a hospital for chemotherapy were invited and parental consent was sought before they were accepted into the study. The study comprised of 1) a parental questionnaire, 2) the collection of medical history and 3) a clinical examination for tooth decay (caries) and mucosal status. Results: A total of 69 patients were invited, and they all participated in this study. Their mean age was 9.2±5.0 and 44 (64%) were males. Twenty-six patients (38%) had no caries experience (DMFT and/or dmft = 0). Higher caries experience was detected in participants that were not born in Hong Kong, had completed active chemotherapy, participated in school dental care service and whose parents had low educational levels. There were 41 patients with active chemotherapy, 24 of whom were diagnosed with acute leukaemia, 5 with haematological malignancies other than leukaemia and 11 with solid tumours. Antimetabolites, cytotoxic antibiotics, alkylating agents and plant alkaloids were administered in 49%, 32%, 24% and 22% of them, respectively. Twenty-six (63%) patients showed no mucosal complications. The most common oral complication was oral mucositis (24%) followed by petechiae (10%). Conclusion: About two-thirds of paediatric and adolescent cancer patients had caries experience, which was more common among those who had completed chemotherapy. Oral mucositis followed by petechiae were the two most common complications of receiving chemotherapy.published_or_final_versio

Encounter complexes and dimensionality reduction in protein-protein association

An outstanding challenge has been to understand the mechanism whereby proteins associate. We report here the results of exhaustively sampling the conformational space in protein–protein association using a physics-based energy function. The agreement between experimental intermolecular paramagnetic relaxation enhancement (PRE) data and the PRE profiles calculated from the docked structures shows that the method captures both specific and non-specific encounter complexes. To explore the energy landscape in the vicinity of the native structure, the nonlinear manifold describing the relative orientation of two solid bodies is projected onto a Euclidean space in which the shape of low energy regions is studied by principal component analysis. Results show that the energy surface is canyon-like, with a smooth funnel within a two dimensional subspace capturing over 75% of the total motion. Thus, proteins tend to associate along preferred pathways, similar to sliding of a protein along DNA in the process of protein-DNA recognition

Development of 〈110〉 texture in copper thin films

Author name used in this publication: C. H. Woo2001-2002 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe