Do the mathematically gifted and talented senior primary school students in Hong Kong understand mathematics?

Students in Hong Kong have been consistently performing well in international comparative studies of mathematics achievement such as the Trend International Mathematics and Science Study (TIMSS) (Beaton et al, 1996; Mullis et al, 1997; Mullis et al, 2000) and the OECD Program for International Student Assessment (PISA) (OECD, 2001; 2003). This research intended to study the mathematically gifted and talented senior primary school students in Hong Kong and to investigate their performances in Mathematical Olympiad. Top-performing students were chosen for interview and they are required to generate explicit principle-based explanations on their answers. It was found that most of the gifted and talented students in Hong Kong solved the mathematical Olympiad problems using conceptual knowledge, while a few of them adopted procedural knowledge.postprin

Reversible acute renal failure in a patient with IgA nephropathy

Reversible acute renal failure is a rare complication of IgA nephropathy. We report a patient with IgA nephropathy who developed acute renal failure after an episode of gross haematuria. Renal biopsy revealed extensive acute tubular damage and red blood cell casts. His renal failure recovered spontaneously without specific treatment. The clinical and pathological features of this IgA nephropathy complication are discussed.published_or_final_versio

Fibrillary glomerulonephritis: a case report

Fibrillary glomerulonephritis is a recently recognised condition. The usual presentation is heavy proteinuria. The diagnosis is established by demonstration of the characteristic Congo-red negative, randomly arranged microfibrils in the glomeruli by electron microscopy. At present, there is no proven effective treatment for this condition and the prognosis is generally poor. The first case of fibrillary glomerulonephritis diagnosed in Hong Kong is reported here in a 38-year-old woman.published_or_final_versio

Acceptors in undoped gallium antimonide

Undoped GaSb materials were studied by temperature dependent Hall (TDH) measurements and photoluminescence (PL). The TDH data reveals four acceptor levels (having ionization energies of 7meV, 32meV, 89meV and 123meV) in the as-grown undoped GaSb samples. The 32meV and the 89meV levels were attributed to the GaSb defect and the VGa-related defect. The Ga Sb defect was found to be the important acceptor responsible for the p-type nature of the present undoped GaSb samples because of its abundance and its low ionization energy. This defect was thermally stable after the 500°C annealing. Similar to the non-irradiated samples, the 777meV and the 800meV PL signals were also observed in the electron irradiated undoped GaSb samples. The decrease of the two peaks' intensities with respect to the electron irradiation dosage reveals the introduction of a non-radiative defect during the electron irradiation process, which competes with the transition responsible for the 777meV and the 800meV PL peaks.published_or_final_versio

BCI-FES training system design and implementation for rehabilitation of stroke patients

Author name used in this publication: Kai-yu TongAuthor name used in this publication: Suk-tak ChanRefereed conference paper2007-2008 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

Oral health status of asthmatic preschoolers in Hong Kong

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Cerebral plasticity after subcortical stroke as revealed by cortico-muscular coherence

Author name used in this publication: Kai-Yu TongAuthor name used in this publication: Suk-Tak Chan2008-2009 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Nitrogen doped-ZnO/n-GaN heterojunctions

Nitrogen-doped ZnO nanorods were prepared by electrodeposition using two different Zn precursors (zinc nitrate and zinc acetate), while all other growth conditions (dopant precursor, concentration, growth temperature, and bias) were identical. We have shown that the precursor used affects the properties of the ZnO nanorods, and that the presence of rectifying properties in n-GaN/N:ZnO heterojunctions is strongly related to the use of nitrate precursor for ZnO growth. The difference in the properties of ZnO obtained from two precursors is attributed to the differences in native defect and impurity concentrations, which could affect the electronic properties of the samples. © 2011 American Institute of Physics.published_or_final_versio

Preclinical activity of gefitinib in non-keratinizing nasopharyngeal carcinoma cell lines and biomarkers of response

This study evaluated the preclinical activity and molecular predictors of response to gefitinib (Iressa®, Astra Zeneca Inc, UK) in nasopharyngeal carcinoma (NPC). The activity of gefitinib was evaluated in four human NPC cell lines-HK1, HONE-1, CNE2, C666-1. A representative gefitinib-sensitive (HK1, IC50 = 250 nM) and gefitinib-resistant cell line (HONE-1, IC 50 > 15 μM) were selected and compared for expression of epidermal growth factor receptor (EGFR) and related ligands, and activation of downstream proteins. Gefitinib induced G1 cycle arrest, apoptosis and inhibited cell invasion more significantly in HK1 than HONE-1 cells. HK1 expressed higher levels of p-EGFR, lower p-AKT and phospho-signal transducer and activator of transcription 3 (p-STAT3) than other cell lines. EGFR gene was found to be amplified in HK1. Gefitinib at IC50 concentrations significantly suppressed EGF-induced activation of p-EGFR, phospho-mitogen-activated protein kinase (p-MAPK) and p-STAT3, but p-AKT showed persistent activation in HK1 and HONE-1 cells. There was no difference in EGFR-ligand expression between the 4 NPC cell lines. In NPC samples derived from non-responders to gefitinib, 50% and 60% showed cytoplasmic and nuclear pi-EGFR expression, respectively, and 33% showed p-AKT expression. EGFR or KRAS mutations were not detected. This study suggests that most NPC cell lines are intrinsically resistant to gefitinib (except HK1 cells), and further studies are needed to confirm whether EGFR gene amplification and persistent AKT activation may influence response to gefitinib in NPC. © 2009 Springer Science+Business Media, LLC.published_or_final_versionSpringer Open Choice, 01 Dec 201

Solution-based growth of ZnO nanorods for light-emitting devices: Hydrothermal vs. electrodeposition

ZnO nanorods have been grown by two inexpensive, solution-based, low-temperature methods: hydrothermal growth and electrodeposition. Heterojunction n-ZnO nanorods/p-GaN light-emitting diodes have been studied for different nanorod growth methods and different preparation of the seed layer. We demonstrate that both the nanorod properties and the device performance are strongly dependent on the growth method and seed layer. All the devices exhibit light emission under both forward and reverse bias, and the emission spectra can be tuned by ZnO nanorod deposition conditions. Electrodeposition of rods or a seed layer results in yellow emission, while conventional hydrothermal growth results in violet emission. © The Author(s) 2010. This article is published with open access at Springerlink.com.published_or_final_versionSpringer Open Choice, 01 Dec 201