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On the Integrability of the Abel and of the Extended Liénard Equations

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Acta Mathematicae Applicatae Sinica 2019年第4期35卷 722-736页

作者： Man kwong mak Tiberiu HARKO Departamento de Fsica Facultad de Ciencias Naturales Universidad de Atacama Copayapu 485 Copiapo Chile Department of Physics Babes-Bolyai University Kogalniceanu Street Cluj-Napoca 400084 Romania School of Physics Sun Yat-Sen University Guangzhou 510275 China

We present some exact integrability cases of the extended Liénard equation y′′+ f(y)(y′)n +k(y)(y′)m + g(y)y′+ h(y) = 0, with n > 0 and m > 0 arbitrary constants, while f(y), k(y), g(y), and h(y) are arbitrary functions. The solutions are obtained by transforming the equation Liénard equation to an equivalent first kind first order Abel type equation given bydv/dy= f(y)v3-n+ k(y)v3-m+ g(y)v2+ h(y)v3, with v = 1/y′.As a first step in our study we obtain three integrability cases of the extended quadratic-cubic Liénard equation,corresponding to n = 2 and m = 3, by assuming that particular solutions of the associated Abel equation are known. Under this assumption the general solutions of the Abel and Liénard equations with coefficients satisfying some differential conditions can be obtained in an exact closed form. With the use of the Chiellini integrability condition, we show that if a particular solution of the Abel equation is known, the general solution of the extended quadratic cubic Liénard equation can be obtained by quadratures. The Chiellini integrability condition is extended to generalized Abel equations with g(y) ≡ 0 and h(y) ≡ 0, and arbitrary n and m, thus allowing to obtain the general solution of the corresponding Liénard equation. The application of the generalized Chiellini condition to the case of the reduced Riccati equation is also considered.

关键词： Abel equation Liénard equation general solutions integrability conditions

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k-Dimensional hashing scheme for hard disk integrity verification in computer forensics

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第10期12卷 809-818页

作者： Zoe Lin JIANG Lucas Chi kwong HUI Siu Ming yiu Kam Pui CHOW School of Computer Science and Technology Harbin Institute of Technology Shenzhen Graduate School Department of Computer Science The University of Hong Kong

Verifying the integrity of a hard disk is an important concern in computer forensics,as the law enforcement party needs to confirm that the data inside the hard disk have not been modified during the investigation.A typical approach is to compute a single chained hash value of all sectors in a specific ***,this technique loses the integrity of all other sectors even if only one of the sectors becomes a bad sector occasionally or is modified *** this paper we propose a k-dimensional hashing scheme,kD for short,to distribute sectors into a kD space,and to calculate multiple hash values for sectors in k dimensions as integrity *** the integrity of the sectors can be verified depending on any hash value calculated using the sectors,the probability to verify the integrity of unchanged sectors can be high even with bad/modified sectors in the hard *** show how to efficiently implement this kD hashing scheme such that the storage of hash values can be reduced while increasing the chance of an unaffected sector to be verified *** results of a 3D scheme show that both the time for computing the hash values and the storage for the hash values are reasonable.

关键词： Computer forensics Digital evidence Hard disk integrity k-Dimensional hashing

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Solitary seminal vesicle metastasis from ileal adenocarcinoma presenting with hematospermia:A case report

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World Journal of Clinical Cases 2021年第23期9卷 6775-6780页

作者： Xiao-Bao Cheng Zhen-Quan Lu Wayne Lam Ming-kwong yiu Ji-Shi Li Department of Surgery The University of Hong Kong-Shenzhen HospitalShenzhen 518053Guangdong ProvinceChina Division of Urology Department of SurgeryQueen Mary HospitalThe University of Hong KongHong KongChina Department of Oncology The University of Hong Kong-Shenzhen HospitalShenzhen 518053Guangdong ProvinceChina

BACKGROUND Although metastatic adenocarcinoma of the ileum is not uncommon,solitary metastasis to the seminal vesicle has not been *** report a patient with recurrent hematospermia diagnosed with metastasis to the seminal vesicle following ileal adenocarcinoma resection,his subsequent management and *** SUMMARY A 46-year-old man presented with recurrent episodes of painless *** was not associated with any lower urinary tract *** had a past medical history of ileal tumor at the terminal ileum with solitary mesenteric lymph node metastasis on presentation,and underwent partial ileectomy and lymphadenectomy 4 years *** investigations included positronemission tomography and computed tomography imaging confirmed the very unusual diagnosis of a solitary tumor at the left seminal *** leftsided vesiculectomy was carried *** analysis with immunohistochemistry showed that CDX-2 was positive and CK7 was negative,and the appearance was consistent with the diagnosis of recurrent metastatic adenocarcinoma of his previously treated intestine *** patient had an uneventful post-operative *** received adjuvant chemoradiotherapy following *** remained asymptomatic until he developed multiple bone and pulmonary metastases one year after *** Clinicians should be aware of hematospermia as the first symptom of metastatic recurrence in patients with a history of ileal adenocarcinoma.

关键词： Seminal vesicle Metastasis Ileal adenocarcinoma Hematospermia Laparoscopic vesiculectomy Case report

Isolated penile urethral injury:A rare case following male coital trauma

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Asian Journal of Urology 2015年第3期2卷 175-178页

作者： Ka Wing Wong Brian Sze Ho Ho Chi Ho Ip Ming kwong yiu Division of Urology Department of SurgeryUniversity of Hong KongPokfulamHong KongChina

Penile fractures are an uncommon urological ***,penile fractures involve the corpus cavernosum and are sometimes associated with urethral *** corpus spongiosum and urethral injuries without concomitant corpus cavernosum injury are,however,*** proper knowledge of the management of penile fractures and urethral injuries,this distinct entity can be diagnosed,assessed and managed successfully without complications.

关键词： Penile fracture Urethral injury Penis Corpus spongiosum Urological trauma Urethroplasty

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在牙科教育及研究中提倡公共卫生

中华口腔医学杂志 1991年第3期26卷 180-181页

作者： Kelvin kwong Yuen mak 香港菲腊亲王牙科医院

香港自1961年开始在食水中加氟,至今已超过25年。自1978年起,香港亦订定了有组织的学校牙科服务。八十年代初期,本院的牙周病学及公共卫

关键词：公共卫生教育牙科

Prostate cancer detection upon transrectal ultrasound-guided biopsy in relation to digital rectal examination and prostate-specific antigen level： what to expect in the Chinese population？

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Asian Journal of Andrology 2015年第5期17卷 821-825,I0010页

作者： Jeremy YC Teoh Steffi KK Yuen James HL Tsu Charles KW Wong Brian SH Ho Ada TL Ng Wai-Kit Ma Kwan-Lun Ho Ming-kwong yiu Department of Surgery Division of Urology Queen Mary Hospital University of Hong Kong Hong Kong China

We investigated the prostate cancer detection rates upon transrectal ultrasound （TRUS）-guided biopsy in relation to digital rectal examination （DRE） and prostate-specific antigen （PSA）, and risk factors of prostate cancer detection in the Chinese population. Data from all consecutive Chinese men who underwent first TRUS-guided prostate biopsy from year 2000 to 2013 was retrieved from our database. The prostate cancer detection rates with reference to DRE finding and PSA level of 〈 4, 4-10, 10.1-20, 20.1-50 and 〉 50 ng ml^-1 were investigated. Multivariate logistic regression analyses were performed to investigate for potential risk factors of prostate cancer detection. A total of 2606 Chinese men were included. In patients with normal DRE, the cancer detection rates were 8.6%, 13.4%, 21.8%, 41.7% and 85.2% in patients with PSA 〈 4, 4-10, 10.1-20, 20.1-50 and 〉 50 ng ml^-1 respectively. In patients with abnormal DRE, the cancer detection rates were 12.4%, 30.2%, 52.7%, 80.6% and 96.4% in patients with PSA 〈 4, 4-10, 10.1-20, 20.1-50 and 〉 50 ng m1-1 respectively. Older age, smaller prostate volume, larger number of biopsy cores, presence of abnormal DRE finding and higher PSA level were associated with increased risk of prostate cancer detection upon multivariate logistic regression analyses （P 〈 0.001）. Chinese men appeared to have lower prostate cancer detection rates when compared to the Western population. Taking the different risk factors into account, an individualized approach to the decision of TRUS-guided biopsy can be adopted.

关键词： Chinese digital rectal examination prostate biopsy prostate cancer prostate-specific antigen

A cross-sectional study on compliance with topical glaucoma medication and its associated socioeconomic burden for a Chinese population

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International Journal of Ophthalmology(English edition) 2017年第2期10卷 293-299页

作者： Man-Hin Lui Jason Chun Ho Lam Yi Lee kwong Tak Siu Wong Pak Long Cheung Sherri Shun Yan Lai Pak Lun Yuen Wai yiu Lam Ho Yan Chan yiu Fai Wong Jimmy Shiu Ming Lai Kendrick Co Shih Li Ka Shing Faculty of Medicine the University of Hong KongPokfulamHong KongChina Department of Ophthalmology Li Ka Shing Faculty of Medicinethe University of Hong KongPokfulamHongKongChina Department of Ophthalmology Queen Mary HospitalPokfulamHong KongChina

AIM： To estimate the overall drug compliance for local Chinese glaucoma patients on long-term topical ***： This was a retrospective cross-sectional ***-seven primary glaucoma patients from the subspecialty clinic of a publicly-funded tertiary care hospital in Hong Kong completed a questionnaire on compliance with topical glaucoma medication,attitude towards glaucoma and therapy and vision related quality of *** was defined as reporting missing more than or equal to 10% of the prescribed topical glaucoma medication during the 2wk immediately prior to the *** between noncompliance and demographics,attitude,disease and treatment status was *** was estimated with quality of life and direct medical cost involved with *** logistic regression on noncompliance was performed on selected ***： Compliance was calculated as 75%（95% CI： 64%-87%） among 57 subjects（mean age 69 y,female 51%）.No statistical significant relationship was established between noncompliance and any single factors or ***（P=0.048） and forgetfulness（P=0.064） were found to be marginally significant predictive factors on noncompliance in multivariable logistic *** might be related（P=0.130） to poorer self-rated vision-associated quality of *** societal cost of noncompliance was estimated to be over 2510 life-years and US$ 3.7 million ***： The compliance of Chinese glaucoma patients in Hong Kong is comparable to other parts in the world,and carries detrimental impacts on individual and societal *** and forgetfulness are two possible independent predictors for noncompliance.

关键词： glaucoma eye drop compliance quality of life

The performance characteristics of prostate-specific antigen and prostate-specific antigen density in Chinese men

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Asian Journal of Andrology 2017年第1期19卷 113-116页

作者： Jeremv YC Teoh Steffi KK Yuen James HL Tsu Charles KW Wong Brian SH Ho Ada TL Ng Wai-Kit Ma Kwan-Lun Ho Ming-kwong yiu Division of Urology Department of Surgery Queen Mary Hospital University of Hong Kong Hong Kong China

We investigated the performance characteristics of prostate-specific antigen （PSA） and PSA density （PSAD） in Chinese men. All Chinese men who underwent transrectal ultrasound-guided prostate biopsy （TRUS-PB） from year 2000 to 2013 were included. The receiver operating characteristic （ROC） curves for both PSA and PSAD were analyzed. The sensitivity, specificity, positive predictive value （PPV） and negative predictive value （NPV） at different cut-off levels were calculated. A total of 2606 Chinese men were included. For the ROC, the area under curve was 0.770 for PSA （P〈 0.001） and 0.823 for PSAD （P〈 0.001）. PSA of 4.5 ng ml^-1 had sensitivity of 94.4%, specificity of 14.1%, PPV of 29.5%, and NPV of 86.9%; PSAD of 0.12 ng ml^-1cc^-1 had sensitivity of 94.5%, specificity of 26.6%, PPV of 32.8%, and NPV of 92.7%. On multivariate logistic regression analyses, PSA cut-off at 4.5 ng ml^-1 （OR 1.61, 95% CI 1.05-2.45, P = 0.029） and PSAD cut-off at 0.12 ng ml^-1 cc^-1 （OR 6.22, 95% CI 4.20-9.22, P 〈 0.001） were significant predictors for prostate cancer detection on TRUS-PB. In conclusion, the performances of PSA and PSAD at different cut-off levels in Chinese men were very different from those in Caucasians. PSA of 4.5 ng ml^-1 and PSAD of O. 12 ng ml^-1 cc^-1 had near 95% sensitivity and were significant predictors of prostate cancer detection in Chinese men.

关键词： Chinese prostate cancer transrectal ultrasound-guided prostate biopsy prostate-specific antigen prostate-specific antigen density

Association of time to prostate-specific antigen nadir and logarithm of prostate-specific antigen velocity after progression in metastatic prostate cancer with prior primary androgen deprivation therapy

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Asian Journal of Andrology 2017年第1期19卷 98-102页

作者： Jeremy YC Teoh James HL Tsu Steffi KK Yuen Peter KF Chiu Samson YS Chan Ka-Wing Wong Kwan-Lun Ho Simon SM Hou Chi-Fai Ng Ming-kwong yiu Division of Urology Department of Surgery The Chinese University of Hong Kong Prince of Wales Hospital Shatin Hong Kong China Division of Urology Department of Surgery Queen Mary Hospital University of Hong Kong Hong Kong China.

We investigated the association of time to prostate-specific antigen nadir （TTPN） and logarithm of prostate-specific antigen velocity after progression Log（PSAVAP） in metastatic prostate cancer with prior primary androgen deprivation therapy （ADT）. All metastatic prostate cancer patients treated with primary ADT from 2000 to 2009 were reviewed. Patients who developed disease progression were included in the subsequent analyses. Patients were categorized into three groups according to their TTPN： TTPN of 〈3 months, 3-17 months, and 〉17 months. We compared the Log（PSAVAP） between the different TTPN groups using Mann-Whitney U-test and Kruskal-Wallis test. Further multiple linear regression analyses on Log（PSAVAP） were performed to adjust for other potential confounding factors. Among 419 patients who were treated with primary ADT, 306 patients developed disease progression with a median follow-up of 28 months, Longer TTPN was associated with lower Log（PSAVAP）（P = 0.008） within all subgroup analyses （TTPN of 〈3 vs 3-17 months, P = 0.020; TTPN of 3-17 vs 〉17 months, P = 0.009; and TTPN of 〈3 vs 〉17 months, P = 0.001）. Upon multiple linear regression analyses, baseline PSA （regression coefficient 0.001, P = 0.045）, PSA nadir （regression coefficient 0.002, P = 0.040）, and TTPN （regression coefficient -0.030, P = 0.001） were the three factors that were significantly associated with Log（PSAVAP）. In conclusion, a longer TTPN was associated with lower Log（PSAVAP） in metastatic prostate cancer patients following primary ADT. TTPN cut-offs at 3 months and 17 months appeared to have prognostic significance in predicting Log（PSAVAP）. TTPN may serve as a good prognostic indicator in deciding the treatment strategy in patients with disease progression.

关键词： androgen deprivation therapy prostate cancer prostate-specific antigen velocity after progression ti me to prostate-specific antigen nadir