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Comparative Analysis of Lactulose and Fructooligosaccharide on Growth kinetics, Fermentation, and Antioxidant Activity of Common Probiotics

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Food and Nutrition Sciences 2018年第3期9卷 161-178页

作者： Evelyn Lu Marie yeung chi Kong yeung Biological Sciences Department California Polytechnic State University San Luis Obispo CA USA Animal Science Department California Polytechnic State University San Luis Obispo CA USA

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 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.

关键词： Prebiotics Oligosaccharides Lactulose FOS Probiotics

Segment routing for traffic engineering and effective recovery in low-earth orbit satellite constellations

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Digital Communications and Networks 2024年第3期10卷 706-715页

作者： Shengyu Zhang Xiaoqian Li Kwan Lawrence yeung Department of Electrical and Electronic Engineering The University of Hong KongHKSARChina National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of ChinaChengduSichuan611731China

Low-Earth Orbit Satellite Constellations(LEO-SCs)provide global,high-speed,and low latency Internet access services,which bridges the digital divide in the remote *** inter-satellite links are not supported in initial deployment(*** Starlink),the communication between satellites is based on ground stations with radio frequency *** to the rapid movement of satellites,this hybrid topology of LEO-SCs and ground stations is time-varying,which imposes a major challenge to uninterrupted service provisioning and network *** this paper,we focus on solving two notable problems in such a ground station-assisted LEO-SC topology,i.e.,traffic engineering and fast reroute,to guarantee that the packets are forwarded in a balanced and uninterrupted ***,we employ segment routing to support the arbitrary path routing in *** solve the traffic engineering problem,we proposed two source routings with traffic splitting algorithms,Delay-Bounded Traffic Splitting(DBTS)and DBTS+,where DBTS equally splits a flow and DBTS+favors shorter ***-lation results show that DBTS+can achieve about 30%lower maximum satellite load at the cost of about 10%more *** guarantee the fast recovery of failures,two fast reroute mechanisms,Loop-Free Alternate(LFA)and LFA+,are studied,where LFA pre-computes an alternate next-hop as a backup while LFA+finds a 2-segment backup *** show that LFA+can increase the percentage of protection coverage by about 15%.

关键词： Fast reroute Low-earth orbit satellite constellation Segment routing Traffic engineering Traffic splitting

SHAPE MEMORY EFFECT OF PU IONOMERS WITH IONIC GROUPS ON HARD-SEGMENTS

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chinese Journal of Polymer Science 2006年第2期24卷 173-186页

作者：胡金莲 Kwok-wing yeung Institute of Textiles and Clothing Hong Kong Polytechnic University Hung HomHong KongChina

SMPU （shape memory polyurethane） non-ionomers and ionomers, synthesized with poly（c-caprolactone）（PCL）, 4, 4＇-diphenylmethane diisocyanate （MDI）, 1,4-butanediol （BDO）, dimethylolpropionic acid （DMPA） were measured with cyclic tensile test and strain recovery test. The relations between the structure and shape memory effect of these two series were studied with respect to the ionic group content and the effect of neutralization. The resulting data indicate that, with the introduction of asymmetrical extender, the stress at 100% elongation is decreased for PU non-ionomer and ionomer series, especially lowered sharply for non-ionomer series; the fixation ratio of ionomer series is not affected obviously by the ionic group content; the total recovery ratio of ionomer series is decreased greatly. After sufficient relaxation time for samples stretched beforehand, the switching temperature is raised slightly, whereas the recovery ratio measured with strain recovery test method is lowered with increased DMPA content. The characterization with FT-IR, DSC, DMA elucidated that, the ordered hard domain of the two series is disrupted with the introduction of DMPA which causes more hard segments to dissolve in soft phase; ionic groups on hard segment enhance the cohesion between hard segments especially at high ionic group content and significantly facilitate the phase separation compared with the corresponding non-ionomer at moderate ionic group content.

关键词： Polyurethane Ionomers Cyclic thermo-mechanical investigations Shape memory effect Cyclic tensile test Strain recovery test.

Exotic structures arising from fake projective planes

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Science china Mathematics 2013年第1期56卷 43-54页

作者： yeung Sai-Kee Department of Mathematics Purdue University

We present examples of exotic structures on pPC2#qPC2 for some small p and q obtained naturally from quotients of fake projective planes in complex geometry,which are classified by the work of Prasad-yeung and Cartwri... 详细信息

关键词： exotic four-folds fake projective planes

ML(n)BiCGStab: Reformulation, Analysis and Implementation

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Numerical Mathematics(Theory,Methods and Applications) 2012年第3期5卷 447-492页

作者： Man-Chung yeung Department of Mathematics University of WyomingLaramieWY 82071USA

With the aid of index functions,we re-derive the ML(n)BiCGStab algorithm in[yeung and Chan,SIAM ***.,21(1999),pp.1263-1290]*** are n ways to define the ML(n)BiCGStab residual *** definition leads to a different ML(n)BiCGStab *** demonstrate this by presenting a second algorithm which requires less *** theory,this second algorithm serves as a bridge that connects the Lanczos-based BiCGStab and the Arnoldi-based FOM while ML(n)BiCG is a bridge connecting BiCG and *** also analyze the breakdown situation from the probabilistic point of view and summarize some useful properties of ML(n)*** issues are also addressed.

关键词： CGS BiCGStab ML(n)BiCGStab multiple starting Lanczos Krylov subspace iterative methods linear systems

The refined physical parameters of transiting exoplanet system HAT-P-24

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Research in Astronomy and Astrophysics 2013年第5期13卷 593-603页

作者： Xiao-Bin Wang Sheng-Hong Gu Andrew Collier Cameron Hong-Bo Tan Ho-Keung Hui chi-Tai Kwok Bill yeung Kam-Cheung National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences School of Physics and Astronomy University of St Andrews North Haugh St Andrews Fife KY16 9SS UK University of chinese Academy of Sciences Hokoon Nature Education cum Astronomical Centre Sik Sik Yuen Hong Kong Astronomical Society

The transiting exoplanet system HAT-P-24 was observed by using CCD cameras at Yunnan Observatory and Hokoon Astronomical Centre, china in 2010 and 2012. In order to enhance the signal to noise ratio of transit events, the observed data are corrected for systematic errors according to Collier Cameron et al.＇s coarse de- correlation and Tamuz et al.＇s SYSREM algorithms. Three new complete transit light curves are analyzed by means of the Markov chain Monte Carlo technique, and the new physical parameters of the system are derived. They are consistent with the old ones from the discovered paper except for a new larger radius Rp = 1.364 Rj of HAT- P-24b, which confirms its inflated nature. By combining the five available epochs of mid-transit derived from complete transit light curves, the orbital period of HAT-P- 24b is refined to P = 3.3552479 d and no obvious transit timing variation signal can be found from these five transit events during 2010-2012.

关键词： exoplanet system -- transit -- individual: HAT-P-24

Outcome of 1355 consecutive transabdominal chorionic villus samplings in 1351 patients

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中华医学杂志(英文版) 2005年第20期000卷 5-11页

作者： LAU Tze kin,LEUNG Tak yeung,FUNG Tak Yuen,Daljit S SAHOTA,LEUNG Tse Ngong Fetal Medicine Unit Department of Obstetrics and Gynaecology Prince of Wales Ho spital chinese University of Hong Kong Shatin Hong Kong SAR china Fetal Medicine Unit Department of Obstetrics and Gynaecology Prince of Wales Ho spital chinese University of Hong Kong Shatin Hong Kong SAR china Fetal Medicine Unit Department of Obstetrics and Gynaecology Prince of Wales Ho spital chinese University of Hong Kong Shatin Hong Kong SAR china Fetal Medicine Unit Department of Obstetrics and Gynaecology Prince of Wales Ho spital chinese University of Hong Kong Shatin Hong Kong SAR china Fetal Medicine Unit Department of Obstetrics and Gynaecology Prince of Wales Ho spital chinese University of Hong Kong Shatin Hong Kong SAR china

Background The true risk of choronic villus sampling (C VS) is poorly defined. The objective of this study was to review the clinical o utcome of transabdominal CVS performed in a university teaching unit, with an em phasis on the complication rate. Methods A comprehensive audit database was maintained for 1351 pregnant women, including 17 sets of twin pregnancies, who had a CVS. Details a nd outcome of all CVSs made in the unit between May 1996 and May 2004 were revie wed. All CVSs were performed by one of 5 operators using the identical techniqu es. Results All procedures were performed transabdominally. A tota l of 1355 CVSs were performed because there were 4 dichorionic twin pregnancies which required 2 punctures. The mean gestation at CVS was (11.8±0.7) weeks, and 97.3% of the procedures were performed between 11 and 13 completed weeks. The majority (96.2%) required only 1 puncture to achieve correct needle placeme nt. The procedure failed to obtain an adequate sample in 4 subjects (0.30%). A total of 1351 chromosomal studies were requested and there was 1 case (0.07%) of culture failure. The results of chromosomal studies were available within 1 4 days in 36.7% of the cases and within 21 days in 94.0%. Overall, 77 chromos omal abnormalities (5.7%) and 5 cases of thalassemia major were detected. Preg nancy outcome was unknown in only 13 singleton subjects (0.96%). In the remain ing 1355 fetuses, there were 76 pregnancy terminations (5.56%), 10 fetal losses with obvious obstetric causes (0.73%), and 21 potentially procedure-relat ed fetal losses (1.54%). In the last group, the majority had one or more co-e xisting obstetric complications. The background fetal loss rate for pregnancies at similar gestational age in the unit was about 0.8%. Therefore, the procedu re-related fetal loss rate was estimated to be at the maximum of 0.74%. Conclusions In experienced hands, first trimester transabdomina l CVS is an accurate and safe invasive prenatal diagnostic procedur

关键词： chorionic villus sampling · postoperative complication · pregnancy outcome

Accumulative Time Based Ranking Method to Reputation Evaluation in Information Networks

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Journal of Computer Science & Technology 2022年第4期37卷 960-974页

作者： Hao Liao Qi-Xin Liu Ze-Cheng Huang Ke-Zhong Lu chi Ho yeung Yi-Cheng Zhang National Engineering Laboratory on Big Data System Computing Technology College of Computer Science and SoftwareEngineeringShenzhen UniversityShenzhen 518060China Guangdong Province Key Laboratory of Popular High Performance Computers Shenzhen UniversityShenzhen 518060China Guangdong Province Engineering Center of china-Made High Performance Data Computing System College of ComputerScience and Software EngineeringShenzhen UniversityShenzhen 518060China Institute of Big Data Intelligent Management and Decision Shenzhen UniversityShenzhen 518060China Department of Science and Environmental Studies The Education University of Hong KongHong Kong 999077China Department of Physics University of FribourgFribourg 1700Switzerland

Due to over-abundant information on the Web, information filtering becomes a key task for online users to obtain relevant suggestions and how to extract the most related item is always a key topic for researchers in various fields. In this paper, we adopt tools used to analyze complex networks to evaluate user reputation and item quality. In our proposed Accumulative Time Based Ranking (ATR) algorithm, we take into account the growth record of the network to identify the evolution of the reputation of users and the quality of items, by incorporating two behavior weighting factors which can capture the hidden facts on reputation and quality dynamics for each user and item respectively. Our proposed ATR algorithm mainly combines the iterative approach to rank user reputation and item quality with temporal dependence compared with other reputation evaluation methods. We show that our algorithm outperforms other benchmark ranking algorithms in terms of precision and robustness on empirical datasets from various online retailers and the citation datasets among research publications. Therefore, our proposed method has the capability to effectively evaluate user reputation and item quality.

关键词： temporal network behavior dynamics reputation evaluation ranking algorithm

Addendum to:Exotic structures arising from fake projective planes(Sci china Math,2013,56:43-54)

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Science china Mathematics 2015年第11期58卷 2473-2476页

作者： yeung Sai-Kee Department of Mathematics Purdue University

The goal of this addendum is to generalize the argument of the original article [5] to handle the case of Cartwright-Steger surface, and to correct misprints in the tables in [5].

关键词：射影平面数学科学中国结构表面