-
[show abstract]
[hide abstract]
ABSTRACT: Alcohol is a widely used drug. Our objective was to examine alcohol pharmacokinetics in Chinese subjects through the breath measurement of blood alcohol concentration (BAC) to identify any measurable covariates that may help explain variability between subjects.
Breath-alcohol measurements of 184 healthy Chinese subjects were collected. Compartmental models including one- and two-compartment process were examined. First-order kinetics was applied to model alcohol absorption and elimination phases. For the sake of simplicity, only the subject's body weight, sex and stomach condition were investigated as covariates in our random effects modelling.
The body as a whole behaves as a single compartment, with the suggested one-compartment model being good enough to characterize the biological process. In line with other studies, food ingestion before/with the dose slowed down alcohol absorption into the central compartment. Female subjects exhibited a significantly higher BAC elimination rate than that of males. Body weight also contributed to the observed inter-subject variability in alcohol clearance.
We present a model for estimating blood-alcohol levels from breath-alcohol measurements. The results of our study are useful particularly in relation to drink-driving prosecutions because of the routine use of breath-alcohol measurements as evidence in such cases through the world.
Journal of Clinical Pharmacy and Therapeutics 12/2010; 36(6):716-24. · 1.57 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Using data from families in which marker genotypes are known for the father, the mother and the affected offspring, a simple statistic for testing for imprinting effects is developed. The statistic considers whether the expected number of families in which the father carries more copies of a particular marker allele than the mother is equal to the expected number of families in which the mother carries more copies of the allele than the father. The proposed parent-of-origin effects test statistic (POET) is shown to be normally distributed and can be employed to test for imprinting in situations where the marker locus need not be a disease susceptibility locus and where the female and male recombination fractions are sex-specific. A simulation study is conducted to characterize the power of the POET and other properties, and its results show that it is appropriate to employ the POET.
Heredity 03/2007; 98(2):85-91. · 4.60 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A study was designed to examine the elimination rate of alcohol from the body of the local Chinese after consumption of different types of alcoholic drinks. The breath alcohol of 184 healthy volunteers was determined and converted into blood alcohol levels after they finished drinking. Information on the type and volume of alcoholic drinks consumed, age group, sex, drinking habit, and drinking on empty stomach or with/after meal was recorded for each participant. The results show that the elimination rate of an individual can be explained in terms of physiological variables including sex and drinking habit. The determined elimination rates allow forensic toxicologists to back calculate the blood alcohol concentration (BAC) of the drivers at the time of accident in drunk driving cases. The elimination rates of blood alcohol at 95% prediction intervals for male and female are in the range of 9.5-23.8 mg/100 ml/h and 11.1-37.1 mg/100 ml/h, respectively.
Forensic Science International 02/2006; 156(2-3):95-101. · 2.30 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Influence curves for the initial and rotated loadings are derived for the maximum likelihood factor analysis (MLFA) model. Cook's distances based on the empirical influence curves of factor loadings are proposed for the identification of influential observations. The distances are shown to be invariant under scale transformation and factor rotation. We find that an observation with a very large Cook's distance based on the sample influence curve may not necessarily exert an excessive influence on the factor loadings pattern but may change the ordering of the factors. The issue of the switching of factors is also studied by means of the empirical influence curve and factor scores.
British Journal of Mathematical and Statistical Psychology 12/2005; 58(Pt 2):345-58. · 1.31 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Allele frequencies for 15 STR loci, namely D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA, which are tested for by PE Applied Biosystem's Identifier kit, were obtained from a sample of 325 unrelated Chinese in Hong Kong.
Forensic Science International 10/2005; 152(2-3):307-9. · 2.30 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The Widmark formula has been widely adopted in forensic applications to drink driving cases for the last 70 years. It is known that the amount of alcohol consumed and the body weight of the drinkers are important information for the estimation of blood alcohol concentration (BAC). However, the direct application of the Widmark factors derived from Caucasian to the calculation of BAC for the Chinese population often encounters serious challenges. Owing to this inherent weakness, a thorough analysis to determine the theoretical Widmark factors for the Chinese population, r(0) at the start of drinking and the practical factors, r(peak), at peak BAC was conducted. In the present study, other factors such as gender, stomach condition and other physiological conditions are taken into account. The determined theoretical Widmark factors, r(0,) for local Chinese male and female are 0.68 and 0.59 (with BAC in the units of weight/volume), respectively, demonstrating the applicability of the Widmark formula to the Chinese population. The practical factors at peak BAC, r(peak), were also determined to serve the forensic purpose of refuting the "hip-flask" defence in drink driving cases. Findings show that gender and stomach condition are the key factors that could statistically explain the variability of both r(0) and r(peak).
Forensic Science International 07/2005; 151(1):23-9. · 2.30 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This paper presents a mobile robot fro routine delivery tasks of medicine, specimen, and medical devices from one station to another in hospitals. This hospital transport robot uses the fluorescent lamps on the ceiling of the corridor as natural landmarks to localize its position and orientation. A simple and efficient algorithm has been developed based on motion continuity and features matching for on-line computation of the position and orientation. A robust method is also presented for the robot to avoid collisions with static obstacles and people moving in the hospital. We have implemented this transport robot in a hospital in Hong Kong. An experimental result was demonstrated to confirm the performance of the localization and navigation algorithms.
Robotics, Intelligent Systems and Signal Processing, 2003. Proceedings. 2003 IEEE International Conference on; 11/2003
-
[show abstract]
[hide abstract]
ABSTRACT: Allele frequencies for nine STR loci namely, D3S1358, HUMvWA, HUMFIBRA/FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820 were obtained from a sample of 198 unrelated Chinese in Beijing, China.
Forensic Science International 11/2001; 121(3):207-9. · 2.30 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In some situations, it can be inferred from the crime circumstances that the mixed stain donors are of different ethnic groups. The evaluation of DNA mixtures with contributors coming from more than one ethnic group is considered under the assumption of independence of alleles within and between ethnic groups. A general formula is derived for the assessment of the weight of evidence in mixed stain problems. This formula is equivalent to that of Fukshansky and Bär, but we give a different derivation. For the convenience of practitioners, the explicit expressions of the likelihood ratios for 14 common cases are presented. The effect of different ethnic groups to the assessment of the evidence is shown in the well-known Simpson case.
Deutsche Zeitschrift für die Gesamte Gerichtliche Medizin 09/2001; 115(1):48-53. · 2.59 Impact Factor
-
Journal of Forensic Sciences 08/2001; 46(4):1000. · 1.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Porphyria cutanea tarda is a metabolic disorder in the haem biosynthetic pathway. It includes a heterogeneous group of conditions, which may be inherited or, more commonly, acquired. Although porphyria cutanea tarda presents with cutaneous lesions only, it is often associated with systemic disease. A 64-year-old Chinese patient, who developed sporadic porphyria cutanea tarda 1 year after the diagnosis of pulmonary melioidosis, is discussed. The patient presented with a history of recurrent photosensitive vesicles, blisters, and skin fragility on the sun-exposed areas of both forearms and hands, 6 months after commencing doxycycline and amoxycillin. Both the histological and biochemical findings were characteristic of porphyria cutanea tarda. All the lesions subsided after cessation of these antibiotics. The patient was free of further lesions at follow-up 6 months later. The association seen in this case between porphyria cutanea tarda and melioidosis is unlikely to be coincidental, because these two diseases are both very rare in Hong Kong. In addition, the temporal relationship between the antibiotic therapy and the clinical course of skin lesions in this patient suggests that the drugs were a trigger factor, precipitating their appearance.
Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 07/2001; 7(2):197-200.
-
[show abstract]
[hide abstract]
ABSTRACT: Allele frequencies for three STR loci, namely, CSF1PO, HUMTHO1 and TPOX, and the AMP-FLP locus D1S80 were obtained from a sample of 351 unrelated Chinese in Hong Kong.
Forensic Science International 02/2001; 115(1-2):103-5. · 2.30 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The allele distributions at the 12 short tandem repeat (STR) loci D3S1358, HUMvWA, HUMFIBRA/FGA, HUMTHO1, HUMTPOX, HUMCSF1P0, D5S818, D13S317, D7S820, D8S1179, D21S11 and D18S51 have been determined for 284 unrelated Chinese in Hong Kong. The combined probability of identity for the 12 STR loci was about 4.1 x 10(-14) and the overall probability of excluding paternity 0.999978. None of the 12 loci were found to deviate from Hardy-Weinberg expectations according to the results of the exact test. There was also little evidence for association of alleles between loci. The results demonstrate that the loci are useful for forensic human identification and parentage testing for the Chinese population in Hong Kong.
Deutsche Zeitschrift für die Gesamte Gerichtliche Medizin 02/2001; 114(4-5):281-4. · 2.59 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Like many other places in the world, Hong Kong has drink-driving legislation which prohibits a driver from having in his blood alcohol exceeding a prescribed limit while in control of a motor vehicle. The accuracy of measuring this alcohol concentration is obviously of prime concern as an erroneous result can avert the administration of justice. The common practice is to deduct all errors from the measured value and compare the deducted value with the prescribed limit, so that the benefit of all errors of the measurement is given to the driver. It is therefore important for any laboratory responsible for measuring blood alcohol concentrations to identify and quantify all errors associated with the measurement. The present study examined 900 blood alcohol determinations carried out by the Hong Kong Government Laboratory (HKGL) on cases of suspected drink driving. The determinations were performed by 5 different analysts with two different sets of instruments during 1995-1997. Statistical analysis indicated that the instruments had no bearing on the random error or variability and that even though analyst was a significant factor on variability, the deviation from the mean so caused was only 0.3% and of no practical significance. When the systematic error introduced by the tolerance limits of the certified alcohol standards (purchased from the Laboratory of Government Chemists, UK) was taken into account, the total uncertainty (random plus systematic errors) of an alcohol determination at 99.5% confidence level was found to be 4%. It is recommended that laboratories engaged in blood alcohol determination should adopt similar statistical treatment of their analytical results to find out the error and to ensure that the results are independent of analyst and instrument used.
Forensic Science International 07/2000; 110(3):207-14. · 2.30 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We assess the performance of the slotted Aloha protocol with capture in a mobile communications environment with Rayleigh and log-normal fading when used with switched-beam smart antennas. We consider the configuration where one receiver is present at each base station and calculate the capture probability, its asymptotic value as the number of colliding packets tends to infinity. The results demonstrate that by using realistic smart antennas with non-zero sidelobes, we can achieve higher performance in terms of capture probability when compared to a conventional antenna system using the slotted Aloha protocol
Vehicular Technology Conference, 1999. VTC 1999 - Fall. IEEE VTS 50th; 02/1999
-
[show abstract]
[hide abstract]
ABSTRACT: We report an investigation into the effect of using smart antennas
on the performance of the slotted ALOHA protocol with capture in a
mobile communications environment with Rayleigh and log-normal fading.
Our results demonstrate that by using smart antennas, we can achieve
higher performance in terms of capture probability and throughput when
compared to a conventional antenna system using the slotted ALOHA
protocol
Wireless Communications and Networking Conference, 1999. WCNC. 1999 IEEE; 02/1999
-
[show abstract]
[hide abstract]
ABSTRACT: The coefficient of variation is commonly used in medical and biological sciences. In this paper, several parametric and non-parametric tests for the equality of coefficients of variation in kappa populations are reviewed. Simulation studies are conducted to compare the sizes and power of these tests. It is found that the parametric tests perform well if the data are normally distributed, but perform poorly if otherwise. The non-parametric test, however, is rather robust against the underlying distribution. An example using data of the Quality Assurance Program from the Hong Kong Medical Technology Association in Haematology and Serology is provided. The insensitivity of the non-parametric test to outliers is demonstrated.
Statistics in Medicine 10/1998; 17(17):2003-14. · 1.88 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Amyopathic dermatomyositis (ADM) is a rare variant of dermatomyositis (DM) in which there is no apparent muscle involvement at initial presentation, but clinical and laboratory evidence of myopathy may appear later. Like DM, it has a known association with malignancy.
To record the occurrence of ADM in Hong Kong during the period from January 1988 to June 1996, and to establish the types of carcinoma with which it is associated.
The records of all patients diagnosed with ADM in three major dermatology clinics in Hong Kong were retrospectively studied to confirm the diagnosis and to look for any associated malignancy at any stage of the disease.
Between 1988 and 1996, six patients in Hong Kong (five men and one woman; mean age, 50 years) fulfilled the criteria of ADM. During a follow-up period ranging from 20 to 90 months (average, 35.6 months), none developed any evidence of myositis. Associated malignancy was found in the five male patients. There were three cases of nasopharyngeal carcinoma (NPC), one case of non-small cell carcinoma of the lung, and one case of metastatic carcinoma of the cervical lymph node of unknown primary. No carcinoma had developed in the female patient during a follow-up period of 90 months.
There is a strong association between ADM and NPC in Hong Kong.
International Journal of Dermatology 10/1998; 37(9):659-63. · 1.14 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Porokeratotic eccrine ostial and dermal duct naevus (PEODDN) is a rare, benign hamartomatous malformation involving the eccrine sweat duct. The existence of filiform keratinous plugs that represent cornoid lamellae overlying dilated infundibula of eccrine ducts is a distinctive feature and the presence of associated abnormal dermal ducts is frequent. We report a patient with PEODDN who exhibited lesions on the left side of her chest. Cases of PEODDN reported in the literature are reviewed. Our experience in treating this patient with ultrapulsed carbon dioxide laser is also presented.
British Journal of Dermatology 05/1998; 138(4):684-8. · 3.67 Impact Factor
-
W K Fung
[show abstract]
[hide abstract]
ABSTRACT: We extend Geisser and Johnson's methods and propose simple tests for linkage equilibrium of fragment lengths between VNTR loci. The tests are shown to have asymptomatically normal or chi-square null distributions. They are applied to the reference databases of Asian populations, including the Hong Kong Chinese, Singapore Chinese, Singapore Malays, and Singapore Indians. It seems that there is little linkage disequilibrium in the data.
American Journal of Forensic Medicine & Pathology 07/1997; 18(2):172-6. · 0.88 Impact Factor
