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Search Results: 1 - 10 of 5479 matches for " Kin-Yeung Wong "
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Link Availability Prediction for Cognitive Radio Ad Hoc Networks  [PDF]
Ling Hou, Kai-Hau Yeung, Kin-Yeung Wong
Journal of Computer and Communications (JCC) , 2014, DOI: 10.4236/jcc.2014.26003
Abstract:

One critical issue for routing in cognitive radio ad hoc networks (CRAHNs) is how to select a reliable path for forwarding traffic. This is because mobility may cause radio links to break frequently. The reliability of a path depends on the availability of those links that constitutes the path. In this letter, we present a novel approach to predict the probability of the availability of the link between two cognitive radio nodes. The prediction is achieved by estimating the link activation and spectrum activation probabilities. Our prediction is verified by simulation and proved to be accurate. This study can provide reliability assurance on dynamic routing for cognitive radio ad hoc networks.

Tools for Attacking Layer 2 Network Infrastructure
Kai-Hau Yeung,Dereck Fung,Kin-Yeung Wong
Lecture Notes in Engineering and Computer Science , 2008,
Abstract:
Enhancing the Security of Chain of Trust in DNSSEC
Kin-Yeung Wong,Wei-Leung Koo,Kai-Hau Yeung
Lecture Notes in Engineering and Computer Science , 2008,
Abstract:
Methylation of miR-34a, miR-34b/c, miR-124-1 and miR-203 in Ph-negative myeloproliferative neoplasms
Chor Sang Chim, Thomas S Wan, Kwan Yeung Wong, Tsz Kin Fung, Hans G Drexler, Kit Fai Wong
Journal of Translational Medicine , 2011, DOI: 10.1186/1479-5876-9-197
Abstract: We studied DNA methylation of these miRs in Philadelphia-negative (Ph-ve) myeloproliferative neoplasms (MPNs). Methylation-specific PCR (MSP), verified by direct sequencing of the methylated MSP products, was performed in cell lines, normal controls and diagnostic marrow samples of patients with MPNs.Methylation of these miRs was absent in the normal controls. miR-34b/c were homozygously methylated in HEL cells but heterozygously in MEG-01. In HEL cells, homozygous miR-34b/c methylation was associated with miR silencing, and 5-aza-2'-deoxycytidine treatment led to re-expression of both miR-34b and miR-34c, consistent with that both miRs are under the regulation of the same promoter CpG island. miR-34a was heterozygously methylated in MEG-01 and K-562. miR-203 was completely unmethylated in K-562 and SET-2 but no MSP amplification was found in both HEL and MEG-01, suggestive of miR deletion. In primary samples, four each had miR-34b/c and -203 methylation, in which two had concomitant methylation of miR-34b/c and -203. miR-34a was methylated in one patient and none had methylation of miR-124-1. Seven patients (15.6%) had methylation of at least one of the four miRs. miR methylation did not correlate with clinical parameters, disease complications or JAK2 V617F mutation.This is the first report of miR hypermethylation in MPNs. miR-203 hypermethylation is not specific to Ph+ve leukemias but also present in Ph-ve MPNs. miR-34b/c methylation was associated with reversible miR silencing. There was no correlation of miR methylation with clinical demographic data or outcome.Philadelphia-negative (Ph-ve) myeloproliferative neoplasm (MPN) is a stem cell disease with proliferation of myeloid lineage, leading to the development of distinct clinical entities including polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) [1-3]. JAK2 V617F mutation, resulting in constitutive activation of JAK-STAT signaling, occurs in about half of the patients wi
Taxifolin Enhances Andrographolide-Induced Mitotic Arrest and Apoptosis in Human Prostate Cancer Cells via Spindle Assembly Checkpoint Activation
Zhong Rong Zhang, Mazen Al Zaharna, Matthew Man-Kin Wong, Sung-Kay Chiu, Hon-Yeung Cheung
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0054577
Abstract: Andrographolide (Andro) suppresses proliferation and triggers apoptosis in many types of cancer cells. Taxifolin (Taxi) has been proposed to prevent cancer development similar to other dietary flavonoids. In the present study, the cytotoxic and apoptotic effects of the addition of Andro alone and Andro and Taxi together on human prostate carcinoma DU145 cells were assessed. Andro inhibited prostate cancer cell proliferation by mitotic arrest and activation of the intrinsic apoptotic pathway. Although the effect of Taxi alone on DU145 cell proliferation was not significant, the combined use of Taxi with Andro significantly potentiated the anti-proliferative effect of increased mitotic arrest and apoptosis by enhancing the cleavage of poly(ADP-ribose) polymerase, and caspases-7 and -9. Andro together with Taxi enhanced microtubule polymerization in vitro, and they induced the formation of twisted and elongated spindles in the cancer cells, thus leading to mitotic arrest. In addition, we showed that depletion of MAD2, a component in the spindle assembly checkpoint (SAC), alleviated the mitotic block induced by the two compounds, suggesting that they trigger mitotic arrest by SAC activation. This study suggests that the anti-cancer activity of Andro can be significantly enhanced in combination with Taxi by disrupting microtubule dynamics and activating the SAC.
Convolutional LSTM Network: A Machine Learning Approach for Precipitation Nowcasting
Xingjian Shi,Zhourong Chen,Hao Wang,Dit-Yan Yeung,Wai-kin Wong,Wang-chun Woo
Computer Science , 2015,
Abstract: The goal of precipitation nowcasting is to predict the future rainfall intensity in a local region over a relatively short period of time. Very few previous studies have examined this crucial and challenging weather forecasting problem from the machine learning perspective. In this paper, we formulate precipitation nowcasting as a spatiotemporal sequence forecasting problem in which both the input and the prediction target are spatiotemporal sequences. By extending the fully connected LSTM (FC-LSTM) to have convolutional structures in both the input-to-state and state-to-state transitions, we propose the convolutional LSTM (ConvLSTM) and use it to build an end-to-end trainable model for the precipitation nowcasting problem. Experiments show that our ConvLSTM network captures spatiotemporal correlations better and consistently outperforms FC-LSTM and the state-of-the-art operational ROVER algorithm for precipitation nowcasting.
Differential Actions of Chlorhexidine on the Cell Wall of Bacillus subtilis and Escherichia coli
Hon-Yeung Cheung, Matthew Man-Kin Wong, Sau-Ha Cheung, Longman Yimin Liang, Yun-Wah Lam, Sung-Kay Chiu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0036659
Abstract: Chlorhexidine is a chlorinated phenolic disinfectant used commonly in mouthwash for its action against bacteria. However, a comparative study of the action of chlorhexidine on the cell morphology of Gram-positive and Gram-negative bacteria is lacking. In this study, the actions of chlorhexidine on the cell morphology were identified with the aids of electron microscopy. After exposure to chlorhexidine, numerous spots of indentation on the cell wall were found in both Bacillus subtilis and Escherichia coli. The number of indentation spots increased with time of incubation and increasing chlorhexidine concentration. Interestingly, the dented spots found in B. subtilis appeared mainly at the hemispherical caps of the cells, while in E. coli the dented spots were found all over the cells. After being exposed to chlorhexidine for a prolonged period, leakage of cellular contents and subsequent ghost cells were observed, especially from B subtilis. By using 2-D gel/MS-MS analysis, five proteins related to purine nucleoside interconversion and metabolism were preferentially induced in the cell wall of E. coli, while three proteins related to stress response and four others in amino acid biosynthesis were up-regulated in the cell wall materials of B. subtilis. The localized morphological damages together with the biochemical and protein analysis of the chlorhexidine-treated cells suggest that chlorhexidine may act on the differentially distributed lipids in the cell membranes/wall of B. subtilis and E. coli.
Synthesis and Crystal Structure of a New Triosmium Alkylidyne Carbonyl Cluster Containing a Chiral Ferrocenylphosphine Ligand
Wai-Yeung Wong
Molecules , 2005, DOI: 10.3390/10060640
Abstract: The synthesis, spectroscopic characterization and X-ray crystal structure of a newchiral triosmium alkylidyne carbonyl cluster, (R,S)-[Os3(μ-H)2(CO)9{μ3-CPPh2(η5-C5H4)Fe(η5-C5H3(PPh2)CH(Me)NMe2)}] (1) are described. Compound 1 crystallizes in thenon-centrosymmetric space group P21 and its absolute configuration has been established.The structure consists of an Os3C metal core with one of the PPh2 moieties of the chiralferrocenylphosphine bonded to the apical alkylidyne carbon atom to give a zwitterioniccluster complex, reminiscent of the phosphorus yli
Negative Priming Under Rapid Serial Visual Presentation
Kin Fai Ellick Wong
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0037023
Abstract: Negative priming (NP) was examined under a new paradigm wherein a target and distractors were temporally separated using rapid serial visual presentation (RSVP). The results from the two experiments revealed that (a) NP was robust under RSVP, such that the responses to a target were slower when the target served as a distractor in a previous trial than when it did not; (b) NP was found regardless of whether the distractors appeared before or after the targets; and (c) NP was stronger when the distractor was more distinctive. These findings are generally similar to those on NP in the spatial search task. The implications for the processes causing NP under RSVP are discussed in the current paper.
Supplementation of Fructooligosaccharide Mildly Improves the Iron Status of Anemic Rats Fed a Low-Iron Diet  [PDF]
Fan Zhang, Ken Kin Lam Yung, Stephen Sum Man Chung, Chi Kong Yeung
Food and Nutrition Sciences (FNS) , 2017, DOI: 10.4236/fns.2017.82019
Abstract: Also known as a prebiotic, fructooligosaccharide (FOS) resists digestion by gastric acid and pancreatic enzymes in vivo, but is preferentially fermented by beneficial intestinal bacteria once it reaches the colon. While some studies suggest that FOS and its fermentation products may influence the iron absorption process, the effects of prolonged FOS supplementation on iron status remain unclear. The objective of this study was therefore to determine the enhancing effects of FOS supplementation on the iron status of anemic rats. Male Sprague-Dawley rats receiving a low-iron diet (12 μg/g) for 14 days showed significantly lower hemoglobin concentration, as well as lower tissue non-heme iron levels than rats receiving a regular diet (45 μg/g), confirming iron-deficiency anemia. On the first day of the feeding trial, two groups of anemic rats (n = 6) were fed the same low-iron diet with or without FOS supplementation, while two other groups of anemic rats were switched to the regular diet with or without FOS supplementation to allow recovery. FOS was provided to the rats by dissolving in water at 5% (w/v). Anemic rats fed the low-iron diet showed a mild increase (p < 0.05) in hemoglobin level after 21 days of FOS supplementation when compared to rats without FOS. For anemic rats switched to the regular diet, hemoglobin level returned to normal after 14 days and FOS supplementation showed no additional effects. Our results suggest that FOS supplementation has a mild enhancing effect on the iron status of anemic subjects on a low-iron diet.
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