Vocational Training Council
VTC Institutional Repository (Vocational Training Council)Not a member yet
3146 research outputs found
Sort by
Discovering high-rise buildings’ “Achilles heel”: a review and evaluation of Urban Renewal Authority’s redevelopment projects
No full textThe use of refusals by Cantonese-speaking preschoolers
No full textThe use of refusal strategy by children has been commomly documented in the literature. Refusal usually appears as a secondary act in response to another speech act, for example, request, offer and invitation. In 1990, Beebe and her colleagues worked on refusals in Japanese EFL learners and developed a detailed framework for analyzing refusals. Comparing witn research on request, studies on the speech act of children\u27s refusal strategies are scarce, especially in Chinese. This presentation is based on findings from a project on the use of refusal strategies by young Cantonese-speaking children in Hong Kong. A total of 80 young children (age 3 to 5, half boys and half girls) were asked to join a role-play task with various toys, pictures and puppets in different scenarios with a research assistant. Children\u27s performance during role-plays were both audio- and video-recorded for analysis. Results show that children used direct refusal strategy (( No ) at an early age (3 years old). Direct + indirect refusal strategies such as No + Excuse, reason and explanation increase with children\u27s age. Other types of indirect strategies were not common in our data. In terms of body language, shaking of the head is the most common gesture accompanied direct refusals. Further discussion and comparison of our findings with other studies on refusals will be made at the presentation
Construction of a functional assembly of modular enzymes for direct biosynthesis of cephalosporins
No full textThe worldwide sale of β-lactam antibiotics represents a more than US$20 billion of business per annum. The development of novel β-lactam antibiotics has been a hot issue in the past few decades. Nevertheless, most of them are synthesised via chemical means, whose processing put extensive burden to our environment. 7-Aminocephalosporanic acid (7-ACA) is a key cephem nucleus for a number of semi-synthetic cephalosporins. Conventional chemical synthesis of 7-ACA is environmentally-damaging, and we therefore aim to develop a “greener” approach to synthesise 7-ACA with potential for industrial applications
A green journey to the making of magic bullets
No full textSemi-synthetic cephalosporins, constituting the largest portion in the worldwide sales of beta-lactam antibiotics, have been used extensively for decades as “magic bullets” to combat microbial infections. The global cephalosporin market was valued at US$78,000 million in 2016 and it is estimated to increase by 14% by 2023. Most of the marketed cephalosporins are semi-synthetic. However, the methodologies involved are environmentally-damaging because toxic chemicals are used. The increasing annual demand of semi-synthetic cephalosporins and the concept of environmental sustainability pose a dire need to develop alternative approaches for “greener” production of antibiotics. Microorganisms have been heralded as a solution to many of the contemporary world’s most pressing issues. One of the frontiers in microbial biotechnology is to help solve environmental and sustainable resources problems, and scientists have been working vigorously to harness single-celled systems to produce high value fine chemicals such as commodity chemicals, therapeutic intermediates, and essential nutrients. Bioprocess technology has operational advantages: the procedures are low cost, high yield, and environmentally-sustainable. My research laboratory has been working on developing a sustainable and effective bioprocess using enzymes for the biosynthesis of 7-aminocephalosporanic acid (7-ACA), a cephem nucleus for the production of nearly two-thirds of the global commercial semi-synthetic cephalosporins. In particular, using bioinformatics and modeling, we have characterised a variant D-amino acid oxidase (DAAO) with enhanced catalytic properties suitable for industrial applications. By using variant DAAO and glutaryl-7-aminocephalosporanic acid acylase (GL-7-ACA acylase), we have patented a two-enzyme biosystems for direct biosynthesis of 7-ACA with overall conversion rate approaching 100%. Immobilised enzymes are more robust and exhibit enhanced resistance to industrial and environmental challenges. However, immobilised enzymes are expensive and preparation involves tedious multi-step schemes. Yeast surface display technology represents a tangible and sustainable alternative approach to immobilised enzymes with industrial relevance. Enzyme biocatalysts are displayed on cell surface where a direct enzyme-substrate interaction is facilitated with higher stability and catalytic activity. The new paradigm in pharmaceutical industry is the development of multi-enzyme sequential reactions in one-pot to minimise enzyme inhibition and formation of by-products. We would like to address the problems and develop a streamlined bioprocess relevant to the concept of environmental sustainability by constructing a functional assembly of DAAO and GL-7-ACA acylase for one-pot production of 7-ACA. We reckon that yeast display technology is particularly suitable for biosynthesis of 7-ACA via an establishment of a functional assembly of enzymes with close proximity. Here, I would like to report the latest findings of my research on this area and the potential industrial applications
Inactivation of Escherichia coli using ultraviolet light emitting diodes (UV-LEDs), monochloramine (NH2CI) and the NH2CI/UV-LED process
No full textThe purpose of this study is to examine the efficiency of monochloramine and UV-LEDs at four different wavelengths (i.e., 255, 265, 285 and 300 nm) for E. coli inactivation. And the potential benefit to E. coli inactivation in the case of sequential exposure to NH2Cl and UV-LEDs (the NH2Cl/UV-LED process) is also investigated. The data suggest that E. coli can be effectively inactivated by the combination of sublethal dose of monochloramine, followed by UV irradiation. Obvious synergism is observed at a relatively high UV dose (i.e., 6 mJ/cm2) and all four wavelengths
Study on improved ploypropylene modified bitumen by incorporating phosphoric acid
No full textThis study presents a research conducted to investigate the properties of polymer modified bitumen (PMB) by using bitumen 60/70 as original bitumen, polypropylene (PP) as modifier, phosphoric acid (H3PO4) as additives, and with wet mixing method combining high shear mix and low shear mix in order to determine the optimum binder-PP ratio PMB for applying in Hong Kong. 18 samples had been prepared in this study, of which the PP contents vary from 2~7% with 1%, 3% and 5% of H3PO4 content. In result, compatibility and stability between PP and bitumen is the control factor for determining the maximum content of PP that can be added into the PMB, and all the PMB sample resulted in better performance in every test conducted in this study except ductility. It is concluded that the optimum binder-PP ratio in terms of upgrading the original bitumen (bitumen 60/70) to grade PG82 for Hong Kong areas is 5% PP with 3% H3PO4
Integrated cyto- and geno- toxicity caused by DBPs formed in seawater chlorination
No full textDisinfection by-products (DBPs) generated in chlorinated waters may pose adverse effects to human health and the ecology. This paper studied the integrated cyto- and geno- toxicity caused by DBPs formed in seawater chlorination under different conditions. Increasing chlorine dosages or decreasing pHs increased more significantly the integrated cyto- and geno- toxicity than the DBP concentrations. Increasing contact times and temperatures also increased the DBP concentrations and integrated genotoxicity. However, the integrated cytotoxicity did not change with increasing contact times, and decreased with increasing temperatures. The differences between the dominancy of DBPs in the integrated cyto- and geno- toxicity versus the dominancy of DBPs in their concentrations were mainly due to the much lower cyto- and geno- toxicity index of three DBPs, dibromoacetaldehyde, dibromochloroacetonitrile and monobromoacetic acid, despite their low concentrations in water
Big data approach as an institutional innovation to tackle Hong Kong’s illegal subdivided unit problem
No full textWhile applications of big data have been extensively studied, discussion is mostly made from the perspectives of computer science, Internet services, and informatics. Alternatively, this article takes the big data approach as an institutional innovation and uses the problem of illegal subdivided units (ISUs) in Hong Kong as a case study. High transaction costs incurred in identification of suspected ISUs and associated enforcement actions lead to a proliferation of ISUs in the city. We posit that the deployment of big data analytics can lower these transaction costs, enabling the government to tackle the problem of illegal accommodations. We propose a framework for big data collection, analysis, and feedback. As the findings of a structured questionnaire survey reveal, building professionals believed that the proposed framework could reduce transaction costs of ISU identification. Yet, concerns associated with the big data approach like privacy and predictive policing were also raised by the professional
