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Search Results: 1 - 10 of 8875 matches for " Marie Yeung "
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Comparative Analysis of Lactulose and Fructooligosaccharide on Growth Kinetics, Fermentation, and Antioxidant Activity of Common Probiotics  [PDF]
Evelyn Lu, Marie Yeung, Chi Kong Yeung
Food and Nutrition Sciences (FNS) , 2018, DOI: 10.4236/fns.2018.93013
Abstract: Prebiotics are non-digestible oligosaccharides that selectively stimulate the growth of beneficial bacteria in the human gut. Fructooligosaccharide (FOS) is a common prebiotic found in food products and infant formula. Lactulose is primarily used as a pharmaceutical ingredient but also shows potential prebiotic activities. Our objectives were to determine and compare the effects of FOS and lactulose on: 1) growth kinetics of common probiotics in aerobic condition; 2) pH and titratable acidity after fermentation; and 3) antioxidant capacity of the probiotics. Ten probiotic and two non-probiotic strains, representing genera Lactobacillus, Bifidobacterium, Bacillus, and Escherichia were assembled. Media used for prebiotics experiment were modified to contain 2% FOS or lactulose as the sole or main carbohydrate source. All experiments were done in triplicate. In aerobic condition, most strains cultured with FOS or lactulose did not grow optimally compared to dextrose (a non-prebiotic), while all four Bifidobacterium spp. showed little growth regardless of the carbohydrate source. In anaerobic condition, lactulose and FOS fermentation of Bifidobacterium spp. yielded similar pH (p = 0.2723), but percent lactic acid, as determined by titratable acidity, was higher after lactulose fermentation (p = 0.0004). The non-probiotic strains were able to utilize both FOS and lactulose, but displayed weaker acid production and higher pH (p < 0.0001) relative to the probiotic strains. Antioxidant activity of spent medium was measured with Trolox as the reference standard. Overall, the antioxidant activity of probiotics was strain-dependent. FOS enhanced the antioxidant activity of Bifidobacterium spp. (p = 0.0002) and Lactobacillus spp. (p = 0.0447), but not probiotic E. coli and Bacillus spp. (p = 0.2599) or non-probiotics (p = 0.8816). In conclusion, lactulose supported growth activities of probiotics to a similar extent as FOS. Lactulose also stimulated higher acid production for Bifidobacterium spp. than FOS in anaerobic condition, thus it might be considered for incorporation into functional food products containing bifidobacteria.
Bilinear Mappings and the Frame Operator  [PDF]
Enrico Au-Yeung
Advances in Pure Mathematics (APM) , 2013, DOI: 10.4236/apm.2013.34062
Abstract:

The theory of frames has been actively developed by many authors over the past two decades, both for its applications to signal processing, and for its deep connections to other areas of mathematics such as operator theory. Central to the study of frames is the frame operator. We initiate an investigation that extends the frame operator to the bilinear setting.

Optimal Consumption under Uncertainties: Random Horizon Stochastic Dynamic Roy’s Identity and Slutsky Equation  [PDF]
David W. K. Yeung
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.52028
Abstract:

This paper extends Slutsky’s classic work on consumer theory to a random horizon stochastic dynamic framework in which the consumer has an inter-temporal planning horizon with uncertainties in future incomes and life span. Utility maximization leading to a set of ordinary wealth-dependent demand functions is performed. A dual problem is set up to derive the wealth compensated demand functions. This represents the first time that wealth-dependent ordinary demand functions and wealth compensated demand functions are obtained under these uncertainties. The corresponding Roy’s identity relationships and a set of random horizon stochastic dynamic Slutsky equations are then derived. The extension incorporates realistic characteristics in consumer theory and advances the conventional microeconomic study on consumption to a more realistic optimal control framework.

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.

Chinese Medicine: a peer-reviewed open access journal for evidence-led Chinese medicine
Hin Yeung
Chinese Medicine , 2006, DOI: 10.1186/1749-8546-1-1
Abstract: CM publishes articles reporting valuable research with general interest in any aspect of Chinese medicine, such as basic research, clinical research, methodologies, theories and diagnoses, materia medica, acupuncture and other non-pharmacologic modalities of the Chinese medical system. CM welcomes submission of papers on application of Chinese medicine in disease prevention, treatment/management, and rehabilitation. In addition to biomedical research, CM also accepts reports on various aspects of Chinese medicine research, including public health, regulation, management, education, technical translation, cultural exchange and internationalization. Multidisciplinary and translational research reports are also strongly encouraged. All research and review articles must be peer-reviewed to ensure that the valuable knowledge drawn from them is evidence-based, scientifically justified and ethical. Peer-review is conducted by at least two internationally recognized experts in the respective fields. Our high calibre reviewers and editors will only accept papers of high quality.Since the 1990s, there has been a phenomenal growth of interest in traditional medicine knowledge and practices, which is evident in the increasing World Health Organization (WHO) activities and publications, such as Global Strategy for Traditional Medicine (2002–2005) [3]. Research activities in Chinese medicine, one of the most used and best documented traditional medicines, have been increasing tremendously worldwide as well. A large portion of the research in Chinese medicine has been carried out in Asia, particularly in China, Japan and Korea, and reported in their native languages. As a result, currently available Chinese medicine literature published in English language journals does not meet the growing demand from the international scientific community for easy access to research findings in this field. Moreover, most Chinese medicine literature is scattered throughout a wide range of scienti
Toward An Effective Quality Assurance of Web-Based Learning: The perspective of Distance Learning Students
Davey YEUNG
The Turkish Online Journal of Distance Education , 2003,
Abstract:
Metastability of a granular surface in a spinning bucket
Chuck Yeung
Physics , 1998, DOI: 10.1103/PhysRevE.57.4528
Abstract: The surface shape of a spinning bucket of granular material is studied using a continuum model of surface flow developed by Bouchaud et al. and Mehta et al. An experimentally observed central subcritical region is reproduced by the model. The subcritical region occurs when a metastable surface becomes unstable via a nonlinear instability mechanism. The nonlinear instability mechanism destabilizes the surface in large systems while a linear instability mechanism is relevant for smaller systems. The range of angles in which the granular surface is metastable vanishes with increasing system size.
Customer Satisfaction and the Consumption Function
Bala Ramasamy,Matthew Yeung
Economics Research International , 2010, DOI: 10.1155/2010/202014
Abstract: This paper evaluates the extent to which the American Customer Satisfaction Index (ACSI) acts as a determining variable of the US consumption function. Results show that the ACSI is a significant self-predictor of personal consumption expenditure, as well as a potent policy variable even when income and wealth are controlled for.
Engineering a DNA damage response without DNA damage
ManTek Yeung, Daniel Durocher
Genome Biology , 2008, DOI: 10.1186/gb-2008-9-7-227
Abstract: Detecting and repairing DNA damage is critical for the faithful transmission of genetic information. In response to DNA lesions, cells activate a complex cellular response, which at its core consists of a signal transduction cascade controlled by members of the PI(3) kinase-like kinase (PIKK) family [1,2]. This signaling cascade, often referred to as the DNA damage checkpoint, primarily aims to coordinate DNA repair with the arrest or slowing down of the cell cycle (the checkpoint). Failure to detect and repair DNA damage can lead to cell death or to genome aberrations that can promote the development of cancer.Like other signaling systems, such as those that operate at the cell surface, DNA damage signaling is under tight spatial and temporal control. The spatial component of this pathway is particularly evident during the response to DNA double-strand breaks (DSBs), the most harmful type of DNA lesion. DSBs elicit the rapid accumulation of DNA damage signaling and repair proteins on the chromatin that surrounds lesions, forming distinctive subnuclear foci [1,2] that are easily detectable by fluorescence microscopy. What is extraordinary about this response is not that there is protein recruitment per se; rather, it is the scale of the phenomenon that is impressive. Indeed, protein recruitment after the induction of DSBs can extend for tens of kilobases on either side of the lesion [3,4]. By inference, DSBs promote the recruitment of dozens, if not hundreds, of molecules to the surrounding chromatin. As described below, protein recruitment at DNA lesions often occurs in a hierarchical manner and involves multiple post-translational modifications. Why is DNA damage signaling organized this way? Recent work published by Evi Soutoglou and Tom Misteli in Science [5] and by David Toczyski and colleagues in Molecular Cell (Bonilla et al. [6]) address this critical question by reverse-engineering the DNA damage response, to spectacular effect.Soutoglou and Misteli [5] and
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
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