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Implementation of digital mammography in radiology

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Implementation of digital mammography in radiology

Application of Conjugate Gradient Approach for Nonlinear Optimal Control Problem with Model-Reality Differences

2010中华医学会影像技术分会第十八次全国学术大会

作者： kok leong Kei Macau SAR CHCSJ Radiology dpt.

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Applied Mathematics 2018年第8期9卷 940-953页

作者： Sie Long Kek Wah June leong Sy Yi Sim kok Lay Teo Department of Mathematics and Statistics Universiti Tun Hussein Onn Malaysia Campus Pagoh Panchor Malaysia Department of Mathematics Universiti Putra Malaysia Serdang Malaysia Department of Electrical Engineering Technology Universiti Tun Hussein Onn Malaysia Campus Pagoh Panchor Malaysia Department of Mathematics and Statistics Curtin University of Technology Perth Australia

In this paper, an efficient computational algorithm is proposed to solve the nonlinear optimal control problem. In our approach, the linear quadratic optimal control model, which is adding the adjusted parameters into the model used, is employed. The aim of applying this model is to take into account the differences between the real plant and the model used during the calculation procedure. In doing so, an expanded optimal control problem is introduced such that system optimization and parameter estimation are mutually interactive. Accordingly, the optimality conditions are derived after the Hamiltonian function is defined. Specifically, the modified model-based optimal control problem is resulted. Here, the conjugate gradient approach is used to solve the modified model-based optimal control problem, where the optimal solution of the model used is calculated repeatedly, in turn, to update the adjusted parameters on each iteration step. When the convergence is achieved, the iterative solution approaches to the correct solution of the original optimal control problem, in spite of model-reality differences. For illustration, an economic growth problem is solved by using the algorithm proposed. The results obtained demonstrate the efficiency of the algorithm proposed. In conclusion, the applicability of the algorithm proposed is highly recommended.

关键词： Nonlinear Optimal Control Conjugate Gradient Approach Iterative Solution Adjusted Parameters Model-Reality Differences

Discrete-Time Nonlinear Stochastic Optimal Control Problem Based on Stochastic Approximation Approach

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Advances in Pure Mathematics 2018年第3期8卷 232-244页

作者： Sie Long Kek Sy Yi Sim Wah June leong kok Lay Teo Department of Mathematics and Statistics Universiti Tun Hussein Onn Malaysia Pagoh Malaysia Department of Electrical Engineering Technology Universiti Tun Hussein Onn Malaysia Pagoh Malaysia Department of Mathematics Universiti Putra Malaysia Serdang Malaysia Department of Mathematics and Statistics Curtin University of Technology Perth Australia

In this paper, a computational approach is proposed for solving the discrete-time nonlinear optimal control problem, which is disturbed by a sequence of random noises. Because of the exact solution of such optimal control problem is impossible to be obtained, estimating the state dynamics is currently required. Here, it is assumed that the output can be measured from the real plant process. In our approach, the state mean propagation is applied in order to construct a linear model-based optimal control problem, where the model output is measureable. On this basis, an output error, which takes into account the differences between the real output and the model output, is defined. Then, this output error is minimized by applying the stochastic approximation approach. During the computation procedure, the stochastic gradient is established, so as the optimal solution of the model used can be updated iteratively. Once the convergence is achieved, the iterative solution approximates to the true optimal solution of the original optimal control problem, in spite of model-reality differences. For illustration, an example on a continuous stirred-tank reactor problem is studied, and the result obtained shows the applicability of the approach proposed. Hence, the efficiency of the approach proposed is highly recommended.

关键词： Nonlinear Optimal Control Output Error Model-Reality Differences Iterative Solution Stochastic Approximation

Reducing risk of transjugular intrahepatic portosystemic shunt using ultrasound guided single needle pass

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World Journal of Gastroenterology 2013年第22期19卷 3528-3530页

作者： Sum leong Hong Kuan kok Pradeep Govender William Torreggiani Department of Radiology Tallaght Hospital Dublin 24 Ireland

Delayed liver laceration following transjugular intrahepatic portosystemic shunt (TIPS) is a serious and likely underdiagnosed complication. It is however an important complication following TIPS, which remains one of the most technically challenging interventional procedures performed. In addition to laceration, a number of complications regarding bleeding and perforation are well described following TIPS procedures. We feel the adoption of techniques such as ours and that of other authors described in the literature using an ultrasoundguided percutaneous transhepatic approach with a small caliber needle provides a safer and less traumatic procedure and should reduce complications of bleeding and almost completely eliminate the risk of liver laceration. Our procedure was successfully performed under conscious sedation rather than general anaesthesia further reducing the overall procedural risk to the patient.

关键词： Transjugular portal systemic shunt Ultrasound guided Haemorrhage Complication Reducing Morbidity Death Liver Laceration

Phytochemicals of six selected herbal plants and their inhibitory activities towards free radicals and glycation

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Food Bioscience 2022年第2期46卷 550-562页

作者： Chen Yuan Wong kok Hoong leong Xuemei He Fengjing Zheng Jian Sun Zhenxing Wang Choon Han Heh Kin Weng Kong Department of Molecular Medicine Faculty of MedicineUniversity of Malaya50603Kuala LumpurMalaysia Department of Pharmaceutical Chemistry Faculty of PharmacyUniversity of Malaya50603Kuala LumpurMalaysia Guangxi Key Laboratory of Fruits and Vegetables Storage-Processing Technology 174 East Daxue Road530007NanningChina Agro-food Science and Technology Research Institute Guangxi Academy of Agricultural Sciences174 East Daxue Road530007NanningChina College of Life Science Southwest Forestry UniversityKunming650224China

In type 2 diabetes mellitus patients,hyperglycaemia speed up the production of advanced glycation end products(AGEs),leading to oxidative stress and various diabetic *** order to identify natural products with potential antioxidant and antiglycative properties,six herbal plants,namely Musa acuminata(flower buds),Bletilla striata(rhizomes),Amomum villosum(dried nuts),Moghania philippinensis(roots),Millettia speciosa(rhizomes),and Spatholobus suberectus(stems)were assessed for their antioxidant and antiglycative *** all the selected samples,both water and ethanolic extracts of *** possessed the highest phenolic,flavonoid and triterpenoid contents,ranging from three to six-fold higher than other plant *** consistent with its phytochemical content,*** also showed the highest antioxidant activities which are comparable,if not higher than the known antioxidants,butylated hydroxytoluene,gallic acid,rutin,quercetin and ursolic ***,*** also displayed the highest antiglycative activities among the six herbal plants measured by two glycation assays using bovine serum albumin-glucose and bovine serum albumin-methylglyoxal as model ***-QToF-MS/MS analysis identified 48 polyphenols and 76 terpenoids,from the water and ethanolic extracts of ***,where 12 polyphenols and 9 terpenoids are common in both *** results also suggested that *** contains compounds such as quercetin,luteolin,apigenin and saponin derivatives,which were reported to exert high antioxidant and antiglycative *** high antioxidant and antiglycative properties suggest the great potential of *** in preventing the formation of AGEs and oxidative stress seen in type 2 diabetes.

关键词： Antiglycation Antioxidant Herb HPLC-QToF-MS/MS Polyphenol Terpenoid

Critical evaluation of contemporary management in a new Pelvic Exenteration Unit: The first 25 consecutive cases

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World Journal of Gastrointestinal Oncology 2017年第5期9卷 218-227页

作者： Min Hoe Chew Yu-Ting Yeh Ee-Lin Toh Stephen Aditya Sumarli Ghee Kheng Chew Lui Shiong Lee Mann Hong Tan Tiffany Priyanthi Hennedige Shin Yi Ng Say Kiat Lee Tze Tec Chong Hairil Rizal Abdullah Terence Lin Hon Goh Mohamed Zulfikar Rasheed kok Chai Tan Choong leong Tang Department of Colorectal Surgery Singapore General Hospital Department of Obstetrics and Gynaecology Singapore General Hospital Department of Urology Singapore General Hospital Department of Orthopaedic Surgery Singapore General Hospital Division of Oncological Imaging National Cancer Centre Singapore Department of Anaesthesiology Singapore General Hospital Vascular Surgery Singapore General Hospital Department of Plastic Reconstructive and Aesthetic SurgerySingapore General Hospital

To critically appraise short-term outcomes in patients treated in a new Pelvic Exenteration (PE) Unit. METHODSThis retrospective observational study was conducted by analysing prospectively collected data for the first 25 patients (16 males, 9 females) who underwent PE for advanced pelvic tumours in our PE Unit between January 2012 and October 2016. Data evaluated included age, co-morbidities, American Society of Anesthesiologists (ASA) score, Eastern Cooperative Oncology Group (ECOG) status, preoperative adjuvant treatment, intra-operative blood loss, procedural duration, perioperative adverse event, lengths of intensive care unit (ICU) stay and hospital stay, and oncological outcome. Quantitative data were summarized as percentage or median and range, and statistically assessed by the χ2 test or Fisher’s exact test, as applicable. RESULTSAll 25 patients received comprehensive preoperative assessment via our dedicated multidisciplinary team approach. Long-course neoadjuvant chemoradiotherapy was provided, if indicated. The median age of the patients was 61.9-year-old. The median ASA and ECOG scores were 2 and 0, respectively. The indications for PE were locally invasive rectal adenocarcinoma (n = 13), advanced colonic adenocarcinoma (n = 5), recurrent cervical carcinoma (n = 3) and malignant sacral chordoma (n = 3). The procedures comprised 10 total PEs, 4 anterior PEs, 7 posterior PEs and 4 isolated lateral PEs. The median follow-up period was 17.6 mo. The median operative time was 11.5 h. The median volume of blood loss was 3306 mL, and the median volume of red cell transfusion was 1475 mL. The median lengths of ICU stay and of hospital stay were 1 d and 21 d, respectively. There was no case of mortality related to surgery. There were a total of 20 surgical morbidities, which occurred in 12 patients. The majority of the complications were grade 2 Clavien-Dindo. Only 2 patients experienced grade 3 Clavien-Dindo complications, and both required procedura

关键词： Colorectal cancer Advanced pelvic tumour Sacrectomy Oncological outcome Pelvic exenteration Chordoma

伦理与审美互彰:族裔美国作家陈美玲与梁志英作品解读(英文)

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外国文学研究 2017年第5期39卷 9-25页

作者：张敬珏加州大学洛杉矶分校英语系

本文以陈美玲与梁志英的四部作品为例,通过族裔美国作品讨论文学伦理学批评。自20世纪六七十年代的民权运动以来,伦理成为促进族裔文学创作的强烈驱动力。笔者认为大部分伦理或文学标准都受到民族、性别、阶级、政治与宗教的影响,因而... 详细信息

本文以陈美玲与梁志英的四部作品为例,通过族裔美国作品讨论文学伦理学批评。自20世纪六七十年代的民权运动以来,伦理成为促进族裔文学创作的强烈驱动力。笔者认为大部分伦理或文学标准都受到民族、性别、阶级、政治与宗教的影响,因而对绝对"客观"的文学伦理学批评提出怀疑,强调伦理与美学的相辅相成与不可分割性。少数族裔作家笔下的阶级剥削、同性恋仇视、性骚扰批判、与族裔文学边缘化等话题也被本文纳入文学伦理学批评的范畴。

关键词：文学伦理学批评美国族裔文学审美学华裔美国文学性骚扰