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Science China Chemistry 2024年第11期67卷 3791-3797页

作者： Debasis Pal Kirana DVeeranna yuk fai wong PAndrew Evans Department of Chemistry Queen’s University90 Bader LaneKingstonK7L 3N6Canada Xiangya School of Pharmaceutical Sciences Central South UniversityChangsha410013China

The Reformatsky reagent derived from ethyl bromoacetate circumvents the challenge associated with the direct regio-and enantioselective iridium-catalyzed allylic alkylation with an unstabilized aliphatic ester enolate. Notably, this work represents the first example of using a Reformatsky reagent in a metal-allyl reaction, which permits the direct construction of enantioenriched β-stereogenic homoallylic esters without preactivation of the pronucleophile or post-reaction modification of the product(e.g., thermal decarboxylation of a 1,3-dicarbonyl). Moreover, the process allows the coupling of a broad range of sterically and electronically diverse electrophiles bearing aryl, heteroaryl and alkenyl derivatives, including the significantly more challenging alkyl-substituted allylic carbonates. The versatility of the ester product is exemplified by a series of functional group manipulations and the development of a concise and efficient enantioselective total synthesis of the natural product,(+)-descurainolide A. Finally, mechanistic studies indicate that the zinc enolate behaves as a soft nucleophile that undergoes outer-sphere alkylation.

关键词： allylic substitution asymmetric catalysis mechanistic studies natural product synthesis Reformatsky reagent

Needle track seeding:A real hazard after percutaneous radiofrequency ablation for colorectal liver metastasis

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World Journal of Gastroenterology 2009年第13期15卷 1653-1655页

作者： Shirley yuk-Wah Liu Kit-fai Lee Paul Bo-San Lai Division of Hepato-biliary and Pancreatic Surgery Department of SurgeryPrince of Wales HospitalThe Chinese University of Hong Kong

Neoplastic needle track seeding following percutaneous radiofrequency ablation(RFA)of secondary liver tumors is exceedingly *** on cutaneous tumor seeding after percutaneous RFA for colorectal liver metastasis are even rarer in the *** we report a case of a 46-year-old female who developed an ulcerating skin lesion along the needle track of a previous percutaneous RFA site around 6 mo after the *** previous RFA was performed by the LeVeen needle for a secondary liver tumor from a primary rectal *** diagnosis of secondary skin metastasis was confirmed by fine needle aspiration *** lesion was successfully treated with wide local *** believe that tumor seeding after percutaneous RFA in our patient was possibly related to its unfavorable subcapsular location and the use of an expansion-type ***,prophylactic ablation of the needle track should be performed whenever ***,alternative routes of tumor ablation such as laparoscopic or open RFA should be considered.

关键词： Radiofrequency catheter ablation Needles Neoplasm seeding Liver neoplasms Skin neoplasms Neoplasm metastasis

Anti-cancer activities of S-allylmercaptocysteine from aged garlic

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Chinese Journal of Natural Medicines 2019年第1期17卷 43-49页

作者： LV Yi SO Kwok-fai wong Nai-Kei XIAO Jia Laboratory of Neuroendocrinology School of Biological SciencesFujian Normal University National Key Disciplines for Infectious Diseases Shenzhen Third People's HospitalThe Second Hospital Affiliated to Southern University of Science and Technology School of Biomedical Sciences Li Ka Shing Faculty of MedicineThe University of Hong Kong

While most types of malignancies remain recalcitrant to treatment, application of natural products or their analogs in daily life has offered some hopes as an effective prophylaxis against cancer onset and progression in the past decades. Emerging evidence supports a link between garlic consumption and decreased cancer incidence. Notably, aged garlic extract(AGE) exhibits stronger anti-cancer activities than that of fresh garlic, by virtue of enrichment of several AGE-specific organosulfur compounds, including S-allylmercaptocysteine(SAMC). In this review, we summarize the up-to-date mechanistic pathways associated with the anti-proliferative, anti-metastatic and pro-apoptotic effects of SAMC in various cancer models. Based upon the proven safety and improved understanding on its anti-neoplastic properties, SAMC has gained recognition as a promising daily food supplement for cancer prevention or management.

关键词： Aged garlic S-allylmercaptocysteine Cancer Molecular pathway Reactive oxygen species

A Second Main Theorem on P^n for difference operator

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Science China Mathematics 2009年第12期52卷 2751-2758页

作者： wong Pit-Mann LAW Hiu-fai wong Philip P.W. Department of Mathematics University of Notre Dame Department of Mathematics University of Hong Kong

The main result of this article is an extension of the Second Main Theorem,of Halburd and Korhonen,for meromorphic functions of finite *** result replaces the counting function of the ramification divisor Nramf(r)in the classical Second Main Theorem by the counting function of a finite difference divisor Npair(r).In this article,the Second Main Theorem of Halburd and Korhonen is extended to the case of holomorphic maps into Pn of finite order.

关键词： finite difference Second Main Theorem finite order ramification

Anaerobic biodegradation of PAHs in mangrove sediment with amendment of NaHCO_3

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Journal of Environmental Sciences 2015年第4期27卷 148-156页

作者： Chun-Hua Li yuk-Shan wong Hong-Yuan Wang Nora Fung-Yee Tam State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental Sciences Department of Biology and Chemistry City University of Hong Kong Department of Biology The Hong Kong University of Science and Technology Key Laboratory of Nonpoint Source Pollution Control Ministry of Agriculture/Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural Sciences State Key Laboratory on Marine Pollution City University of Hong Kong

Mangrove sediment is unique in chemical and biological properties. Many of them suffer polycyclic aromatic hydrocarbon（PAH） contamination. However, the study on PAH biological remediation for mangrove sediment is deficient. Enriched PAH-degrading microbial consortium and electron acceptor amendment are considered as two effective measures. Compared to other electron acceptors, the study on CO2, which is used by methanogens, is still seldom. This study investigated the effect of Na HCO3 amendment on the anaerobic biodegradation of four mixed PAHs, namely fluorene（Fl）, phenanthrene（Phe）,fluoranthene（Flua） and pyrene（Pyr）, with or without enriched PAH-degrading microbial consortium in mangrove sediment slurry. The trends of various parameters, including PAH concentrations, microbial population size, electron-transport system activities, electron acceptor and anaerobic gas production were monitored. The results revealed that the inoculation of enriched PAH-degrading consortium had a significant effect with half lives shortened by 7–13 days for 3-ring PAHs and 11–24 days for 4-ring PAHs. While Na HCO3 amendment did not have a significant effect on the biodegradation of PAHs and other parameters, except that CO2 gas in the headspace of experimental flasks was *** of the possible reasons is that mangrove sediment contains high concentrations of other electron acceptors which are easier to be utilized by anaerobic bacteria, the other one is that the anaerobes in mangrove sediment can produce enough CO2 gas even without adding Na HCO3.

关键词： Anaerobic biodegradation Electron acceptor amendment Mangrove sediment Na HCO3amendment Polycyclic aromatic hydrocarbon

On limit behavior of quasi-local mass for ellipsoids at spatial infinity

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Communications in Theoretical Physics 2020年第1期72卷 102-110页

作者： Xiaokai He Leong-fai wong Naqing Xie School of Mathematics and Computational Science Hunan First Normal UniversityChangsha 410205China School of Mathematical Sciences Fudan UniversityShanghai 200433China

We discuss the spatial limit of the quasi-local mass for certain ellipsoids in an asymptotically flat static spherically symmetric *** ellipsoids are not nearly round but they are of interest as an admissible parametrized foliation defining the Arnowitt–Deser–Misner *** Hawking mass of this family of ellipsoids tends to-∞.In contrast,we show that the Hayward mass converges to a finite ***,a positive mass type theorem is *** limit of the mass has a uniform positive lower bound no matter how oblate these ellipsoids *** result could be extended for asymptotically Schwarzschild *** numerical simulation in the Schwarzschild spacetime illustrates that the Hayward mass is monotonically increasing near infinity.

关键词： quasi-local mass asymptotically flat limit behavior

Late retroperitoneal recurrence of hepatocellular carcinoma 12 years after initial diagnosis

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World Journal of Gastroenterology 2010年第17期16卷 2187-2189页

作者： Tiffany Cho-Lam wong Ka-fai To Simon See-Ming Hou Sidney Kam-Hung Yip Chi-fai Ng Department of Surgery Prince of Wales HospitalThe Chinese University of Hong Kong Department of Anatomical and Cellular Pathology The Chinese University of Hong Kong

Hepatocellular carcinoma (HCC) is an aggressive tumor with poor long-term ***,we present an unusual patient with a solitary recurrence of HCC in the right kidney 12 years after the initial *** illustrates the importan... 详细信息

关键词： Hepatocellular carcinoma Late recurrence Metastasis Retroperitoneal

A Survey on Recent Advances and Challenges in Reinforcement Learning Methods for Task-oriented Dialogue Policy Learning

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Machine Intelligence Research 2023年第3期20卷 318-334页

作者： Wai-Chung Kwan Hong-Ru Wang Hui-Min Wang Kam-fai wong The Systems Engineering and Engineering Management Department The Chinese University of Hong KongHong Kong 999077China

Dialogue policy learning(DPL)is a key component in a task-oriented dialogue(TOD)*** goal is to decide the next action of the dialogue system,given the dialogue state at each turn based on a learned dialogue *** learning(RL)is widely used to optimize this dialogue *** the learning process,the user is regarded as the environment and the system as the *** this paper,we present an overview of the recent advances and challenges in dialogue policy from the perspective of *** specifically,we identify the problems and summarize corresponding solutions for RL-based dialogue policy *** addition,we provide a comprehensive survey of applying RL to DPL by categorizing recent methods into five basic elements in *** believe this survey can shed light on future research in DPL.

关键词： Dialogue policy learning(DPL) task-oriented dialogue system(TOD) reinforcement learning(RL) dialogue system Markov decision process

Patients with Helicobacter pylori positive and negative duodenal ulcers have distinct clinical characteristics

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World Journal of Gastroenterology 2005年第23期11卷 3518-3522页

作者： Kent-Man Chu Ka-fai Kwok Simon Law Kam-Ho wong Department of Surgery

AIM: To assess the clinical characteristics of Helicobacterpylori(H pylori) negative duodenal ***: Patients with an endoscopic diagnosis of duodenal ulcer between 1996 and 2002 were included in the present study. Patients were considered to be negative for Hpylori, if both histological examination and rapid urease test of biopsy specimens were negative. A comparison was made between patients with H pyloripositive and negative duodenal ***: A total of 1 343 patients were studied. Their mean age was 54.7±0.5 years. There was a male preponderance (M:F = 2.5:1). Three hundred and ninetyeight patients (29.6%) did not have H pylori infection. The annual proportion of patients with H pylori negative duodenal ulcers increased progressively from 1996 to2002. On multivariate analysis, patients with H pylorinegative duodenal ulcer were more likely to be older, have concomitant medical problem, pre-existing malignancy, recent surgery, underlying sepsis, or taken non-steroidal anti-inflammatory drugs. In terms of clinical presentations, patients with H pylori negative duodenal ulcer were more likely to present with bleeding, multiple ulcers and larger ***: The proportion of patients with H pylori negative duodenal ulcers is on the rise because of a continued drop in incidence of H pylori positive duodenalulcers in recent years. Such patients have distinct clinical characteristics and it is important to ascertain the H pylori status before starting eradication therapy.

关键词： Helicobacter pylori Duodenal ulcer

Potential role of Lycium barbarum polysaccharides in glaucoma management:evidence from preclinical in vivo studies

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Neural Regeneration Research 2023年第12期18卷 2623-2632页

作者： Yamunadevi Lakshmanan Francisca Siu Yin wong Kwok-fai So Henry Ho-Lung Chan Centre for Eye and Vision Research(CEVR) 17W Hong Kong Science ParkHong Kong Special Administrative RegionChina Guangdong-Hongkong-Macao(GHM)Institute of CNS Regeneration Jinan UniversityGuangzhouGuangdong ProvinceChina Department of Ophthalmology LKS Faculty of MedicineThe University of Hong KongHong Kong Special Administrative RegionChina Laboratory of Experimental Optometry(Neuroscience) School of OptometryThe Hong Kong Polytechnic UniversityHong Kong Special Administrative RegionChina Research Centre for SHARP Vision(RCSV) The Hong Kong Polytechnic UniversityHong Kong Special Administrative RegionChina University Research Facilities in Behavioral and Systems Neuroscience(UBSN) The Hong Kong Polytechnic UniversityHong Kong Special Administrative RegionChina

In recent years,the pharmacological benefits of herbal extracts have been revisited for their potential neuroprotective effects in *** polysaccharides extracted from the fruits of Lycium barbarum L.,or Lycium barbarum polysaccharides,exert their anti-aging effect through reducing oxidative stress,modulating the immune response,enhancing neuronal responses,and promoting *** therapeutic efficacy of Lycium barbarum polysaccharides in preserving retinal ganglion cells and their functions was demonstrated in a range of experimental models of optic *** include the acute and chronic ocular hypertension models,the partial optic nerve transection model,and the ischemic-reperfusion injuries *** on these findings,Lycium barbarum polysaccharides appear to be a good candidate to be developed as a neuroprotective agent for treating multifactorial *** review aims to present a comprehensive review on the latest preclinical evidence on the pre-and post-treatment benefits of Lycium barbarum polysaccharides in retinal ganglion cell *** possible mechanisms of Lycium barbarum polysaccharides mediating retinal ganglion cell neuroprotection will also be ***,the potential research gaps in the effective translation of Lycium barbarum polysaccharides treatment into clinical glaucoma management will be discussed.

关键词： animal model complementary and alternative medicine glaucoma retinal ganglion cell Lycium barbarum polysaccharide neuroprotection neuro-rescue ocular hypertension post-treatment pre-treatment