23 research outputs found
Tagging one million volumes in a 2.0 environment: lessons and experiences of implementing RFID technology at the Main Library, The University of Hong Kong
Conference Title: Looking Back, Moving Forward: Asian Libraries in the World of Informationpublished_or_final_versio
Nevus of Ota: a new classification based upon the response to laser treatment
published_or_final_versio
Isolated microspore culture of Chinese flowering cabbage (Brassica campestris ssp parachinensis)
Microspores of several genotypes of Brassica campestris ssp. parachinensis have been cultured in vitro and induced to undergo embryogenesis and plant formation. Conditions favourable for embryogenesis in this species include a bud size of 2-2.9 mm, NLN-13 culture medium (Nitsch and Nitsch 1967; Lichter 1981, 1982; Swanson 1990), and an induction through exposure to 32 degrees C for a period of 48 h. Longer periods of an elevated temperature for induction of embryogenesis resulted in embryo abortion at early developmental stages. With the protocol developed here, microspores of 60-80\% of donor plants could be induced to produce embryos, although embryo yields were low, i.e. 2-5 embryos per 10 buds. Some genotypes responded to culture conditions with high numbers of embryo formation (100-150 embryos per 10 buds) but most of these subsequently failed to mature. The pattern of cell division and morphological changes of the microspores in culture were studied using various microscopic techniques
Reflective space: The medical library as a mindfulness sanctuary
Like their fellow medical students around the world, at the University of Hong Kong (HKU), medical students’ minds are also occupied with acronyms for differential diagnoses, timetables, lunch plans, their Facebook pages, and the incessant inner chatter that clutter minds. Mindfulness is an increasingly evidence-based approach to de-cluttering of the mind, bringing about present moment awareness, and enabling attention in difficult situations. It can be practiced in any setting but is best facilitated in a physical space that mirrors the peace and calm being sought. Thus, the natural coupling of a deliberately designated reflective space in the library for such practice is presented as a fresh approach to reflection
Production of excreted human epidermal growth factor (hEGF) by an efficient recombinant Escherichia coli system
Recombinant Escherichia coli JM101 strains harbouring plasmids pWKW2 or lacUV5par8EGF, both encoding human epidermal growth factor (hEGF), were used in fermentations to optimize levels of excreted hEGF. Medium composition, inducer level, growth stage at induction and culture conditions, were optimized with respect to volumetric production of the recombinant protein. MMBL medium, with glucose at 5 g/l and tryptone as nitrogen source, was chosen. Isopropyl-beta-D-thiogalactopyranoside(IPTG) concentrations of 0.1 mM for E. coli JM101[pWKW2] and 0.2 mM for E. coli K-12 JM101[lacUV5par8EGF], were found to give the best hEGF production levels. The volumetric yields of hEGF were maximal when the cultures were induced in the mid-logarithmic phase. Growth temperature had a significant effect on hEGF yield. A simple continuous fed-batch process for cultivation of E. call JM101[pWKW2] was developed. The maximum concentration of excreted hEGF attained in continuous fed-batch cultivation was 325 mg/l, as compared to 175 mg/l, in batch cultivation. The hEGF produced from the continuous fed-batch cultivation was substantiated by SDS-PAGE and immunoblotting. (C) 1999 Elsevier Science Ltd. All rights reserved
Human epidermal growth factor excreted by recombinant Escherichia coli K-12 has the correct N-terminus and is fully bioactive
The high stability and productivity of recently developed Escherichia coli JM101 strains expressing human epidermal growth factor (hEGF) facilitated scale-up of hEGF production, and a protocol to purify hEGF from bacterial culture supernatant was developed, hEGF-containing supernatant from an induced hEGF-expressing recombinant E. coli culture was purified by: (A) QAE Sephadex A-25 ion-exchange chromatography; (B) Sephadex G-25 desalting; (C) SP-Sepharose cation-exchange chromatography; and (D) reverse-phase HPLC. The hEGF obtained was pure by HPLC and SDS-PAGE. The N-terminus of the purified hEGF was authentic. Commercial pure hEGF, and hEGF purified as described, were assessed for bioactivity, and yielded superimposable curves. The recovery of hEGF with this protocol was 30% of original, while the purity was 97-100%.link_to_subscribed_fulltex