2,289 research outputs found

    Interview by Law Ho Man Carmen

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    Mr Law is 51 years old who was born in Guangdong Zhuhoi in 1949\u27s, just after WWII. He lived and studied in Zhuhoi until 23 years old. He immigrated to Hong Kong at 23 years old illegally. According to his family, they were not rich but their relationship was very good. He has parents, eleven brothers and sister. However, all his brothers had dead and lost during WWII, expect his elder sister and his 6th elder brother. His elder sister and his brother always took care his family. Although they were not living together, they loved each other and had a good relationship. Talking about his studies, he had gone to school at 9 years old. Until the Civil Revolution, he needed to take part in the revolution, so he stopped to go to school. He was F.1 at that time. In conclusion, he thinks that there had a lot of difference between the childhood of his children and his childhood. He thinks that the changing of environment is an important reason. It makes the attitude of his children towards him is totally difference from his childhood

    Distributed Linear Quadratic Regulator Robust to Communication Dropouts

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    We present a solution to deal with information package dropouts in distributed controllers for large-scale networks. We do this by leveraging the System Level Synthesis approach, a control framework particularly suitable for large-scale networks that addresses information exchange in a very transparent manner. To this end, we propose two different schemes for controller synthesis and implementation. The first one synthesizes a controller inherently robust to dropouts, which is later implemented in an offline fashion. For the second approach, we synthesize a collection of controllers offline and then switch between different controllers online depending on the current dropouts detected in the system. The two approaches are illustrated and compared by means of a simulation example.Comment: Accepted contribution to the 21st World Congress of the International Federation of Automatic Control, 202

    Defining scalable cell culture processes for Biosimilar candidates

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    Biosimilar process development is technically challenging compared to novel drug development due to the need to achieve comparable product quality attributes (PQAs) as the brand product. Cell culture process development plays a critical role in modulating PQAs such as sialic acid and glycans. PQA modulation is challenging because often times the change of one PQA may affect other PQAs and/or titer. This poster describes Momenta’s systematic approach to developing scalable cell culture processes for biosimilar candidates while achieving sufficiently high titer and comparable sialylation and N-glycan profiles. In addition to conventional methods of screening media and feeds and optimizing process operating parameters to modulate PQAs, we introduced different process levers such as trace metals and nucleotide sugar precursors into our basal medium and feeds based on our scientific understanding of the molecule of the brand product and the metabolic and enzymatic activities in the cell. With the synergetic approach of media and feeds screening, process operating parameter optimization and process lever addition, in one case study we were able to increase sialic acid levels by about 25% while decreasing a key N-glycan peak by about 5%, achieving comparable PQA profiles as the brand product. In another case study, we successfully increased sialic acid by about 25% while increasing titer by about 50%. Both processes have been successfully scaled up from bench top bioreactors to single-use 250L and 2000L bioreactors

    Using activity transitions to trigger proactive messages

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    Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 113-116).The proliferation of mobile devices and their tendency to present information proactively has led to an increase in device generated interruptions experienced by users. These interruptions are not confined to a particular physical space and are omnipresent. One possible strategy to lower the perceived burden of these interruptions is to cluster non-time-sensitive interruptions and deliver them during a physical activity transition. Since a user is already "interrupting" the current activity to engage in a new activity, the user will be more receptive to an interruption at this moment. This work compares the user's receptivity to an interruption triggered by an activity transition against a randomly generated interruption. A mobile computer system detects an activity transition with the use of wireless accelerometers. The results demonstrate that using this strategy reduces the perceived burden of the interruption.by Joyce Ho.M.Eng

    Promoter de-methylation of cyclin D2 by sulforaphane in prostate cancer cells

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    Sulforaphane (SFN), an isothiocyanate derived from cruciferous vegetables, induces potent anti-proliferative effects in prostate cancer cells. One mechanism that may contribute to the anti-proliferative effects of SFN is the modulation of epigenetic marks, such as inhibition of histone deacetylase (HDAC) enzymes. However, the effects of SFN on other common epigenetic marks such as DNA methylation are understudied. Promoter hyper-methylation of cyclin D2, a major regulator of cell cycle, is correlated with prostate cancer progression, and restoration of cyclin D2 expression exerts anti-proliferative effects on LnCap prostate cancer cells. Our study aimed to investigate the effects of SFN on DNA methylation status of cyclin D2 promoter, and how alteration in promoter methylation impacts cyclin D2 gene expression in LnCap cells. We found that SFN significantly decreased the expression of DNA methyltransferases (DNMTs), especially DNMT1 and DNMT3b. Furthermore, SFN significantly decreased methylation in cyclin D2 promoter regions containing c-Myc and multiple Sp1 binding sites. Reduced methlyation of cyclin D2 promoter corresponded to an increase in cyclin D2 transcript levels, suggesting that SFN may de-repress methylation-silenced cyclin D2 by impacting epigenetic pathways. Our results demonstrated the ability of SFN to epigenetically modulate cyclin D2 expression, and provide novel insights into the mechanisms by which SFN may regulate gene expression as a prostate cancer chemopreventive agent

    Evaluation of a peer counselling programme to sustain breastfeeding practice in Hong Kong

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    <p>Abstract</p> <p>Background</p> <p>Peer counselling is reported to increase breastfeeding rates. We evaluated an intervention consisting of mainly telephone contact peer counselling programme on breastfeeding duration and exclusivity.</p> <p>Methods</p> <p>Peer counsellors (PCs) were mothers who had successfully breastfed and had received formal training. Following a postnatal visit, they provided scheduled telephone consultations (Days 1, 4, 7, Weeks 2, 4, 8, and Month 4) to PC group mothers (n = 100) who continued breastfeeding their infants after discharge. Control group mothers (n = 100) received routine care.</p> <p>Results</p> <p>After adjusting for mothers' previous breastfeeding experiences, mothers' working status and breastfeeding problems, no statistical differences in mothers' feeding methods (exclusive, almost exclusive or predominant breastfeeding) were noted at the three follow-up times for intervention and control mothers respectively (Day 5: 37%/38%, 46%/53%, 57%/63%; Month 3: 10%/9%, 17%/23%, 20%/26%; Month 6: 2%/1%, 18%/18%, 18%/19%). All differences between the groups were not significant. Also, there was no evidence to suggest that PC intervention prolonged breastfeeding duration.</p> <p>Conclusion</p> <p>The lack of effect of our PC intervention may reflect the low baseline breastfeeding rate and low value placed on breastfeeding in our population, the type of PC intervention or group allocation biases.</p> <p>Trial registration</p> <p>ISRCTN93605280.</p

    Extraction of phenolic antioxidants from four selected seaweeds obtained from Sabah

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    Algal have attracted attention from biomedical scientists as they are a valuable natural source of secondary metabolites that exhibit antioxidant activities. In this study, single-factor experiments were conducted to investigate the best extraction conditions (ethanol concentration, solid-to-solvent ratio, extraction temperature and extraction time) in extracting antioxidant compounds and capacities from four species of seaweeds (Sargassum polycystum, Eucheuma denticulatum, Kappaphycus alvarezzi variance Buaya and Kappaphycus alvarezzi variance Giant) from Sabah. Total phenolic content (TPC) and total flavonoid content (TFC) assays were used to determine the phenolic and flavonoid concentrations, respectively, while 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picylhydrazyl (DPPH) radical scavenging capacity assays were used to evaluate the antioxidant capacities of all seaweed extracts. Results showed that extraction parameters had significant effect (p < 0.05) on the antioxidant compounds and antioxidant capacities of seaweed. Sargassum polycystum portrayed the most antioxidant compounds (37.41 ± 0.01 mg GAE/g DW and 4.54 ± 0.02 mg CE/g DW) and capacities (2.00 ± 0.01 μmol TEAC/g DW and 0.84 ± 0.01 μmol TEAC/g DW) amongst four species of seaweed

    Magnetic Fields and Massive Star Formation

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    Massive stars (M>8M > 8 \msun) typically form in parsec-scale molecular clumps that collapse and fragment, leading to the birth of a cluster of stellar objects. We investigate the role of magnetic fields in this process through dust polarization at 870 μ\mum obtained with the Submillimeter Array (SMA). The SMA observations reveal polarization at scales of \lsim 0.1 pc. The polarization pattern in these objects ranges from ordered hour-glass configurations to more chaotic distributions. By comparing the SMA data with the single dish data at parsec scales, we found that magnetic fields at dense core scales are either aligned within 4040^\circ of or perpendicular to the parsec-scale magnetic fields. This finding indicates that magnetic fields play an important role during the collapse and fragmentation of massive molecular clumps and the formation of dense cores. We further compare magnetic fields in dense cores with the major axis of molecular outflows. Despite a limited number of outflows, we found that the outflow axis appears to be randomly oriented with respect to the magnetic field in the core. This result suggests that at the scale of accretion disks (\lsim 10^3 AU), angular momentum and dynamic interactions possibly due to close binary or multiple systems dominate over magnetic fields. With this unprecedentedly large sample massive clumps, we argue on a statistical basis that magnetic fields play an important role during the formation of dense cores at spatial scale of 0.01 - 0.1 pc in the context of massive star and cluster star formation.Comment: Accepted for publication in Astrophysical Journa
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