A simulation impact evaluation of a cigarette excise tax increase on licit and illicit cigarette consumption and tax revenue in 36 European countries.

OBJECTIVES: To assess the impact of a simulated 10% tax-induced cigarette price increase on licit and illicit consumption and tax revenues in 36 European countries. METHODS: Employing panel data for licit and illicit cigarette consumption, fixed effects regression models were applied for different income clusters. RESULTS: Total cigarette consumption dropped by about 3.1% as a result of the simulated tax-induced price increase. Annual illicit cigarette consumption increased by 1.52%, (95% confidence interval: 0.21, 2.83), while annual licit cigarette consumption decreased by 4.61% (95% confidence interval: -6.51, -2.72) in the observed 36 European countries. With total consumption decreasing by about 8%, the Czech Republic, Latvia, Lithuania, Poland and Slovakia were affected the most by the price hike. More specifically, licit consumption in these countries decreased by 18.43% (95% confidence interval: -19.91, -16.95) while illicit use increased by 10.99% (95% confidence interval: 6.01, 15.96). Moreover, the overall annual tobacco tax revenue increased by US$14.69 billion in the simulation. CONCLUSION: Results of the study suggest that European policy makers continue to implement tobacco taxation policies to control smoking prevalence and national health care expenditures. At the same time, efforts to kerb contraband activities along EU Eastern borders should be intensified.

Pre-operative serum albumin level substantially predicts post-operative morbidity and mortality among patients with colorectal cancer who undergo elective colectomy.

The quantitative relationship between serum albumin level and surgical outcomes has not been clearly established. This study included 3732 patients with colon cancer who underwent a potentially curative colectomy. Post-operative mortality and morbidity were analysed according to the patients' demographic data, pre-operative comorbidities, and tumour-related factors. Age, asthma, renal impairment, and albumin level were significantly associated with post-operative morbidity and mortality in the multivariate analyses. Logistic regression analysis revealed linear relationships of post-operative morbidity and mortality with albumin level. The morbidity and mortality rates decreased by 7.3% and 15.6%, respectively, for each 0.1 g/dL increase in albumin level. This finding remained significant in the hypoalbuminaemia subgroup but not in the normoalbuminaemia subgroup. That is, the morbidity and mortality rates significantly decreased by 8.7% and 17.7%, respectively (both P < 0.001), in the former group and decreased by 2.7% (P = 0.112) and 11.6% (P = 0.092), respectively, in the latter group. This study demonstrated that serum albumin level linearly predicted the post-operative morbidity and mortality among the colorectal cancer patients. Pre-operative serum albumin level may therefore be used as a continuous rather than a categorical marker of disease severity, especially among patients with hypoalbuminaemia.

Smoking-related changes or brand switching? Smokers' anticipated responses to a large increase in Taiwan's Tobacco Health and Welfare Surcharge.

OBJECTIVES: This study examines the impact on smokers' behaviour of a planned increase in the Health and Welfare Surcharge of Tobacco Products in Taiwan. STUDY DESIGN: This study used a structured questionnaire to perform telephone interviews. Stratified random sampling was applied to interview current smokers aged 18-65 years in Taiwan. METHODS: Based on nationwide survey data of smokers' responses to future increases in cigarette prices, this study used multinomial logistic regression to perform its analyses. RESULTS: After the proposed increase in the Health and Welfare Surcharge of Tobacco Products, subsequent cigarette price increases would motivate nearly 30% of the smokers to adopt smoking-related changes and 10% to change to lower-priced brands. CONCLUSIONS: The study suggests that a large increase in the Health and Welfare Surcharge of Tobacco Products would lead to considerable changes in smoking behaviour, which in turn would increase cessation rate at the population level.

Modelling the vicious circle between obesity and physical activity in children and adolescents using a bivariate probit model with endogenous regressors.

The increasing prevalence of obesity in children and adolescents has become one of the most important public health issues around the world. Lack of physical activity is a risk factor for obesity, while being obese could reduce the likelihood of participating in physical activity. Failing to account for the endogeneity between obesity and physical activity would result in biased estimation. This study investigates the relationship between overweight and physical activity by taking endogeneity into consideration. It develops an endogenous bivariate probit model estimated by the maximum likelihood method. The data included 4008 boys and 4197 girls in the 5th-9th grades in Taiwan in 2007-2008. The relationship between overweight and physical activity is significantly negative in the endogenous model, but insignificant in the comparative exogenous model. This endogenous relationship presents a vicious circle in which lower levels of physical activity lead to overweight, while those who are already overweight engage in less physical activity. The results not only reveal the importance of endogenous treatment, but also demonstrate the robust negative relationship between these two factors. An emphasis should be put on overweight and obese children and adolescents in order to break the vicious circle. Promotion of physical activity by appropriate counselling programmes and peer support could be effective in reducing the prevalence of obesity in children and adolescents.

Design and testing of a uniformly solar energy TIR-R concentration lenses for HCPV systems.

In this paper, total internal reflection-refraction (TIR-R) concentration (U-TIR-R-C) lens module were designed for uniformity using the energy configuration method to eliminate hot spots on the surface of solar cell and increase conversion efficiency. The design of most current solar concentrators emphasizes the high-power concentration of solar energy, however neglects the conversion inefficiency resulting from hot spots generated by uneven distributions of solar energy concentrated on solar cells. The energy configuration method proposed in this study employs the concept of ray tracing to uniformly distribute solar energy to solar cells through a U-TIR-R-C lens module. The U-TIR-R-C lens module adopted in this study possessed a 76-mm diameter, a 41-mm thickness, concentration ratio of 1134 Suns, 82.6% optical efficiency, and 94.7% uniformity. The experiments demonstrated that the U-TIR-R-C lens module reduced the core temperature of the solar cell from 108 °C to 69 °C and the overall temperature difference from 45 °C to 10 °C, and effectively relative increased the conversion efficiency by approximately 3.8%. Therefore, the U-TIR-R-C lens module designed can effectively concentrate a large area of sunlight onto a small solar cell, and the concentrated solar energy can be evenly distributed in the solar cell to achieve uniform irradiance and effectively eliminate hot spots.

Neuroanatomical and morphometric study of S100ß positive astrocytes in the entorhinal cortex during ageing in the 3xTg-Alzehimer's disease mouse model.

Astrocytes contribute to the progression of neurodegenerative diseases, including Alzheimer's disease (AD). Here, we report the neuroanatomical and morphometric analysis of astrocytes in the entorhinal cortex (EC) of the aged wild type (WT) and triple transgenic (3xTg-AD) mouse model of AD. Using 3D confocal microscopy, we determined the surface area and volume of positive astrocytic profiles in male mice (WT and 3xTg-AD) from 1 to 18 months of age. We showed that S100ß-positive astrocytes were equally distributed throughout the entire EC in both animal types and showed no changes in Nv (number of cells/mm3) nor in their distribution at the different ages studied. These positive astrocytes, demonstrated an age-dependent gradual increase in their surface area and in their volume starting at 3 months of age, in both WT and 3xTg-AD mice. This last group demonstrated a large increase in both surface area and volume at 18 months of age when the burden of pathological hallmarks of AD is present (69.74% to 76.73% in the surface area and the volume, for WT and 3xTg-AD mice respectively). We observed that these changes were due to the enlargement of the cell processes and to less extend the somata. In fact, the volume of the cell body was increased by 35.82% in 18-month-old 3xTg-AD compared to WT. On the other hand, the increase on the astrocytic processes were detected as soon as 9 months of age where we found an increase of surface area and volume (36.56% and 43.73%, respectively) sustained till 18 month of age (93.6% and 113.78%, respectively) when compared age-matched non-Tg mice. Moreover, we demonstrated that these hypertrophic S100ß-positive astrocytes were mainly associated with Aß plaques. Our results show a severe atrophy in GFAP cytoskeleton in all cognitive areas; whilst within the EC astrocytes independent to this atrophy show no changes in GS and S100ß; which can play a key role in the memory impairment.

High ligation of the fistula track by lateral approach: a modified sphincter-saving technique for advanced anal fistulas.

AIM: Ligation of the intersphincteric fistula track is a novel surgical procedure with the advantage of avoiding anal incontinence. We conducted a preliminary investigation of a modified technique for complicated trans-sphincteric anal fistula by high ligation of the track using a lateral approach. METHOD: From June 2010 to May 2011, 10 patients received high ligation of the fistula track using a lateral approach. Patients selected for the procedure had a mature trans-sphincteric type of anal fistula that involved a significant amount of the external sphincter. Patients with early fistulous abscess or with a history of previous anal surgery were excluded. The surgical technique involved making an incision from the external opening and extending this towards the direction of the internal opening, dissection of the fistula from the underlying soft tissue, high ligation above the internal sphincter and removal of the distal part of the fistula track for pathological examination. RESULTS: Of the 10 patients, eight were men and the mean ± SD age was 40.5 ± 7.23 years. The median (range) duration of follow-up was 7 (6-10) months. In all patients, the wound was completely healed by the sixth postoperative week. Two cases of recurrence were noted later and were successfully managed by traditional fistulotomy. CONCLUSION: High-ligation surgery of the fistula track for trans-sphincteric anal fistula, aimed at total anal sphincter preservation, has shown encouraging early results. Long-term follow-up and randomized controlled trials are necessary.

Population dose from medical exposure in Taiwan for 2008.

PURPOSE: The largest contribution to the population dose from man-made ionizing radiation sources is the medical exposure. Exposure to patients from medical examinations is of interest because it is a global indicator for the quality of radiology practice. Due to the different healthcare systems and the considerable variations in the equipment and manpower in radiology, the population dose from medical exposure varies by a large extent in different countries. This dose from different diagnostic procedures provides information that can be used to establish national reference levels. It is also useful to determine the priority in terms of dose reduction so as to optimize the protection of patients in a cost-effective manner. In the present work, the collective effective doses due to different medical modalities were estimated for the Taiwan population in 2008. METHODS: The collective effective dose from medical exposure was calculated using information on the number of procedures and the average effective dose per procedure. The frequency of procedures was extracted from the National Health Insurance (NHI) research database. The enrollment of Taiwan population in the NHI program was 99.48% in 2008. The average effective dose per procedure was derived from hospital surveys, measured data, and published results. RESULTS: Estimates of the collective effective dose were made for different medical modalities, i.e., the conventional radiography and fluoroscopy, computed tomography, interventional fluoroscopy, nuclear medicine, and dental radiography. Each modality was further divided into relevant classes by the body part or organ system. Among 23 037 031 Taiwan population in 2008, the annual examination frequencies per 1000 population were 550, 55.1, 15.6, 13.6, and 112 for the conventional radiography and fluoroscopy, computed tomography, interventional fluoroscopy, nuclear medicine, and dental radiography, respectively. The corresponding collective effective doses were 3277, 8608, 2743, 2303, and 28 man-Sv, respectively. Thus, the average effective dose per caput was 0.74 mSv, which was in the range of 0.3-1.5 mSv for the 12 European countries estimated for 2008. CONCLUSIONS: In the period from 1997 to 2008, the procedure frequency per 1000 population increased by a factor of 2.3 for computed tomography, 2.2 for interventional fluoroscopy, 1.8 for conventional radiography and fluoroscopy, and 1.5 for nuclear medicine. It demonstrated that the medical utilization of imaging facilities raised rapidly.

Mucinous adenocarcinoma showing different clinicopathological and molecular characteristics in relation to different colorectal cancer subgroups.

BACKGROUND: Mucinous adenocarcinoma (MAC) is frequently reported to be associated with patients of young-age sporadic colorectal cancer (YSCC) and hereditary nonpolyposis colorectal cancer (HNPCC). This study is aimed to investigate whether the clinicopathological characteristics of MAC of HNPCC patients are distinct from those of YSCC patients. PATIENTS AND METHODS: Eighty-two HNPCC and 68 YSCC patients recorded in the colorectal cancer registry of Chang Gung Memorial Hospital at Linkou, Taiwan, between January 1, 1995 and December 31, 2001 were included in this study. Clinicopathological and molecular variables of MAC and non-MAC of HNPCC and YSCC patients were compared accordingly. RESULTS: Compared to non-MAC, MAC significantly showed higher frequencies of poor differentiation (32% vs. 8.2%, p = 0.001), advanced tumor stage (76% vs. 47%, p = 0.002), loss of mismatch repair protein (MMR) expression (74% vs. 44%, p = 0.023), and increased MUC2 expression (98% vs. 61%, p < 0.001). MAC of HNPCC patients showed predominant right-sided colon involvement, whereas MAC of YSCC patients displayed predominance in the left colon (79% vs. 22%, p = 0.001). Among the non-MAC counterparts, more differences were detectable including tumor stage, loss of MMR expression, and increased MUC1 expression. Furthermore, both MAC and non-MAC of YSCC patients showed higher frequencies of advanced tumor stage (81% vs. 62%, p = 0.072). In contrast, the incidence of loss of MMR expression in MAC and non-MAC of HNPCC patients is not significantly different (86% vs. 70%, p = 0.323). CONCLUSIONS: Significantly different tumor localization was observed between mucinous YSCC (left colon predominance) and mucinous HNPCC (right colon predominance).

Effect of cigarette taxes on the consumption of cigarettes, alcohol, tea and coffee in Taiwan.

OBJECTIVES: To analyse whether a health tax of 10 New Taiwan Dollars (NT$) (US$0.3) imposed on cigarettes in 2009 will help to reduce cigarette consumption, and whether or not the cigarette tax will affect consumption of alcohol, coffee and tea. STUDY DESIGN: Time series data for consumption and retail prices of tobacco, alcohol, tea and coffee were collected and analysed for the period 1973-2007. METHODS: To establish the Central Bureau of Statistics demand function to estimate the overall demand price elasticities of cigarettes, alcohol, tea and coffee, a seemingly unrelated regression analysis was used. The independent variables were annual consumption of cigarettes, alcohol, tea and coffee. The dependent variables were prices of and expenditures on cigarettes, alcohol, tea and coffee. RESULTS: The estimated own-price elasticities for cigarettes and alcohol are close to -0.726. The own-price elasticities for tea and coffee are less than those for cigarettes and alcohol. Hence, it is predicted that the NT$10 health tax on cigarettes will reduce cigarette consumption by a significant 13.19%. Analysis of cross-price elasticity reveals that alcohol is complementary to cigarettes. CONCLUSIONS: Taxation is an effective smoking control policy tool that not only helps to reduce consumption of cigarettes, but also reduces consumption of alcoholic beverages.

Early effective drainage in the treatment of loculated tuberculous pleurisy.

The role of early effective drainage in loculated tuberculous (TB) pleurisy treatment remains unclear. Consecutive patients with TB pleurisy subjected to anti-TB treatment and pigtail drainage (n = 64) were divided into three groups: 1) patients with free-flowing effusions irrigated with saline (free-flowing group; n = 20); 2) patients with loculated effusions irrigated with streptokinase (streptokinase group; n = 22); and 3) patients with loculated effusions irrigated with saline (saline group; n = 22). Pleural irrigation was performed for 3 days consecutively and the effusion drained as completely as possible. Outcomes were assessed for 12 months by clinical symptoms, effusion removed, radiological scores for effusion amount, lung function and occurrence of residual pleural thickening. The total effusion volumes removed were significantly greater in the free-flowing (2.36+/-1.62 L) and streptokinase groups (2.59+/-1.77 L) than in the saline group (1.28+/-1.21 L). Compared with the saline group, the free-flowing and streptokinase groups showed significant improvement in radiological scores and forced vital capacity at different time-points during follow-up, and a significantly lower occurrence of residual pleural thickening. All outcome variables were comparable between the streptokinase and free-flowing groups. In summary, early effective drainage and complete anti-tuberculosis treatment may hasten clearance of pleural effusion, reduce residual pleural thickening occurrence and accelerate pulmonary function recovery in patients with symptomatic loculated tuberculous pleurisy.

Results of an international comparison of activity measurements of 68Ge.

An international key comparison, identifier CCRI(II)-K2.Ge-68, has been performed. The National Institute of Standards and Technology (NIST) served as the pilot laboratory, distributing aliquots of a 68Ge/68Ga solution. Results for the activity concentration, CA, of 68Ge at a reference date of 12h00 UTC 14 November 2014 were submitted by 17 laboratories, encompassing many variants of coincidence methods and liquid-scintillation counting methods. The first use of 4π(Cherenkov)ß-γ coincidence and anticoincidence methods in an international comparison is reported. One participant reported results by secondary methods only. Two results, both utilizing pure liquid-scintillation methods, were identified as outliers. Evaluation using the Power-Moderated Mean method results in a proposed Comparison Reference Value (CRV) of 621.7(11)kBqg-1, based on 14 results. The degrees of equivalence and their associated uncertainties are evaluated for each participant. Several participants submitted 3.6mL ampoules to the BIPM to link the comparison to the International Reference System (SIR) which may lead to the evaluation of a Key Comparison Reference Value and associated degrees of equivalence.

Association of sex, adiposity, and diet with HDL subclasses in middle-aged Chinese.

BACKGROUND: There is limited information regarding the associations of lifestyle factors and sex with HDL subclasses containing apolipoprotein (apo) A-I (Lp A-I) and both apo A-I and apo A-II (Lp A-I:A-II). OBJECTIVE: We sought to examine the relations between 2 major HDL subclasses and sex, menopausal status, nutrient intakes, and adiposity. DESIGN: We conducted interviews and measured blood variables in 409 government employees aged 40-59 y in Taiwan. RESULTS: Women (n = 203) had significantly higher concentrations of HDL cholesterol, Lp A-I, and Lp A-I:A-II than did men (n = 206). Postmenopausal women (n = 72) had higher concentrations of HDL cholesterol, Lp A-I, and Lp A-I:A-II than did premenopausal women (n = 131). Body mass index and waist-to-hip ratio were strong predictors of and exerted an independent additive effect on Lp A-I concentrations in both men and women. However, body adiposity was associated with Lp A-I:A-II concentrations only in men. Waist-to-hip ratio was an independent determinant of Lp A-I but not of Lp A-I:A-II in men and postmenopausal women after adjustment for age, body mass index, smoking, and diet. Although there were relatively weak associations between dietary factors and both HDL subclasses (r = 0.01-0.26) in men and women according to bivariate analyses, multiple regression models showed that total fat, saturated fat, and cholesterol intakes were significantly correlated with HDL cholesterol and both Lp A-I and Lp A-I:A-II in men, but not in women. CONCLUSION: Our data suggest that body adiposity and dietary fat consumption affect 2 major HDL subclasses differently depending on subject sex and menopausal status.

Prospective study comparing wounds closed with tape with sutured wounds in colorectal surgery.

HYPOTHESIS: To test the efficacy of adhesive paper tape in the closure of clean-contaminated wounds following elective colorectal resection. DESIGN: A prospective, nonrandomized controlled study. SETTING: A medical center that offers a mixture of primary, secondary, and tertiary care services. PATIENTS: The group undergoing skin closure with paper tape (PT group) consisted of 150 patients. The group undergoing skin closure with interrupted suture (IS group) also comprised 150 patients. All 300 patients underwent elective colorectal resection in 1997. MAIN OUTCOME MEASURES: The duration of skin closure, wound complication rate, and cosmetic appearance of the scar at 6 months after operation were compared using the chi(2)test or t test. RESULTS: The mean +/- SD average duration of skin closure was 116 +/- 23 seconds for the PT group and 457 +/- 64 seconds for the IS group (P<.01). The wound complication rate was 3.3% (3 cases with wound infection; 2 with wound separation) for the PT group and 3.3% (5 cases with wound infection) for the IS group (P = 1.0). No significant differences were found between the narrowest width (mean +/- SD, 2.2 +/- 0.9 mm vs 2.3 +/- 1.0 mm) and widest width (mean +/- SD, 4.7 +/- 2.0 mm vs 4.3 +/- 1.8 mm) of scar formation between the 2 groups at 6 months after the operation. Ninety-eight percent of patients in the PT group reported satisfaction with their scar, compared with 92% in the IS group (P =.03). CONCLUSION: Compared with the traditional suture method, paper tape closure in the treatment of clean-contaminated wounds was less time consuming and produced greater patient satisfaction with no increased rate of wound complications.

Management of anorexic patients in radiotherapy: a prospective randomized comparison of megestrol and prednisolone.

Megestrol acetate and corticosteroid have been demonstrated to be effective in the treatment of anorexia in patients with advanced cancer. The purpose of this preliminary study is to evaluate the role of megestrol acetate and prednisolone in the treatment of anorexia induced during whole pelvis external irradiation. Fifty-two patients were randomized in this prospective study to either receive megestrol acetate (40 mg orally four times a day), prednisolone (10 mg orally three times a day), or placebo (1 tablet orally three times a day) for 21 consecutive days. Body weight, appetite, performance status, sense of well-being, and complications were assessed every 3 days. Both the megestrol acetate group and the prednisolone group showed improvement in body weight gain, appetite, performance status, and sense of well-being. Appetite improvement was statistically significant in the megestrol acetate group (P = 0.024) when compared with the placebo group. There were no complications during the 21-day trial.

Psychiatric morbidity and post-traumatic symptoms among survivors in the early stage following the 1999 earthquake in Taiwan.

This study reports the clinical psychiatric presentations and post-traumatic symptoms among 525 survivors at Yu-Chyr District in Nantou County who sought psychiatric service in the first month following the devastating earthquake that struck the central area of Taiwan. All subjects received psychiatric interviews and assessments using the 12-item Chinese Health Questionnaire (CHQ-12) and a checklist for post-traumatic symptoms. The most common psychiatric symptoms reported were insomnia, palpitations, nervousness, and dizziness with headache. Eleven percent of the subjects reported having thought of death or having suicidal ideation. The mean score on the CHQ-12 was 6.43 (S.D.=2.89). The rate of probable psychiatric morbidity as defined by a CHQ-12 score > or =3 was 89.9%. Post-traumatic symptoms were very prevalent, particularly symptoms of re-experiencing the earthquake and hyper-arousal. Factors significantly associated with high psychiatric morbidity were being female, serious destruction of property and house, and personality characteristics of nervousness and obsessiveness. Findings of this study suggest that early psychiatric intervention, including pharmacological treatment for acute stress disorder, is indicated during the early stages following a disastrous earthquake.

Mussel watch: a review of Cu and other metals in various marine organisms in Taiwan, 1991-98.

This study presents the distribution of Cu, Zn, Pb, Cd, Hg and As in various marine organisms collected along the western coast of Taiwan from 1991 to 1998, and also evaluates the time variation of Cu in oysters before (1980-85) and after (1986-98) the "green oyster" incident. The results show that relatively high geometric mean (GM) concentrations of Cu, Zn, Pb, Cd, As and Hg were generally found in Crassostrea gigas (Cu=229 microg/g, Zn=783 microg/g), Gomphina aeguialtera (Pb=30.3 microg/g), Tegillarca granosa (Cd=2.85 microg/g), Thais clavigera (As=96.9 microg/g) and Parapenaeopsis cornuta (Hg=1.35 microg/g), respectively. Especially, maximum Cu and Zn concentrations (GM=229 and 783 microg/g, respectively) in oysters (C. gigas) from different culture areas were much higher than those of the other organisms by about 1.13-458 and 2.40-63.7 times, respectively. Similarly, rock-shells (Thais clavigera) had a high capacity for accumulating Cu (GM=202 microg/g) and Zn (GM=326 microg/g) under the same physico-chemical conditions. The highest GM Cu and Zn concentrations of 1108 (range from 113 to 2806) and 1567 (range from 303 to 3593) microg/g were obtained in oysters from the Hsiangshan coastal area, one of the most important oyster culture areas in Taiwan. However, the highest GM Cd and As concentrations of 6.82 and 19.3 microg/g were found in oysters from the Machu Islands. Mean Cu concentrations in the oysters from the Erhjin Chi estuary declined from 2194+/-212 microg/g in 1986-90 to 545 microg/g (GM) in 1991-96. In the Hsiganshan area, GM Cu concentrations of 909 microg/g (1991-96) and 1351 microg/g (1997-98) in oysters were significantly higher than those of 201 microg/g (1980-85) and 682 microg/g (1986-90). The gradually increasing levels of Cu and Zn in the oysters from the Hsiangshan area have been observed year by year.

Natural frequency assessment of stability of root keeper magnetic devices.

The aim of the study was to evaluate the potential for using natural frequency (NF) as an indicator for assessing the stability of a magnetic keeper device used in prosthodontic treatment. A three-dimensional finite element (FE) model of a root keeper-cement-dentine system was established for NF analysis. The model was first validated against a series of in vitro experiments. Then, NF values of the first vibrational mode of the FE model with various boundary conditions were calculated. The in vitro results showed that the measured NF values of the root keeper-incisor units decreased significantly (p<0.01) from 9.07 +/- 0.37 to 5.73 +/- 0.10 kHz when the units were embedded in simulated bony tissue. Results obtained from FE simulations demonstrated that the root keeper would fully loosen when the constant values of the spring elements were lower than 10(4) N-m(-1). Furthermore, a linear increase in the NF values of the model was observed from 6.16 to 15.52 kHz, when the constant was increased from 10(4) to 10(7) N-m(-1), and the values then reached a plateau. The results indicate that the NF value of a root keeper has the potential to be used for monitoring the stability of such a device.

Factors influencing the dynamic behaviour of human teeth.

Modal analysis is carried out to test the natural frequencies of certain human teeth, including central incisors (CIs), canines (CAs), first premolars (FPs) and first molars (FMs). A total number of 1007 teeth are tested, taking into account tooth type, oral location, age and gender, to analyse the effects of the above-mentioned factors on the natural frequency of the sample teeth. The results reveal that no significant difference in the natural frequency is noted among teeth in the four different intra-oral quadrants. Nevertheless, tooth type and age elicit an effect upon the value of the natural frequency of teeth. On the other hand, the mean value for the natural frequency of CIs (1.27 +/- 0.15 kHz), CAs (1.30 +/- 0.15 kHz), FPs (1.27 +/- 0.15 kHz) and FMs (1.16 +/- 0.12 kHz) for males are significantly lower (p < 0.01) than the analogous figure for females (1.41 +/- 0.21 kHz for CIs, 1.40 +/- 0.18 kHz for CAs, 1.37 +/- 0.20 kHz for FPs, and 1.25 +/- 0.16 kHz for FMs). Moreover, the natural frequency of teeth in male subjects varies with age (p < 0.05). The highest mean frequency of CIs, CAs and FPs for the male subjects is found for the group aged between 40 and 49 years. On the other hand, the natural frequency for the similar set of teeth for the female subjects is shown to be in no way associated with age.

Prognostic value of anti-Epstein-Barr virus antibodies in nasopharyngeal carcinoma (NPC).

INTRODUCTION: Epstein-Barr virus (EBV) is a ubiquitous human herpes virus with worldwide infection. It is associated with Burkitt's lymphoma in Africa and nasopharyngeal cancer (NPC) in Asian countries. EBV-coded DNA was found to be present in epithelial elements of NPC, and is usually associated with non-keratinizing (WHO type II) or undifferentiated carcinoma (WHO type III). Transcriptional analyses of EBV genome expression in NPC demonstrate an activated viral state in some of these tumors, leading to elevated levels of serum anti-viral capsid antigen (VCA) antibody in NPC patients. METHODS: Eighty patients with histological diagnoses of NPC according to the 1978 WHO classification were referred to the Department of Radiation Oncology at Chang-Hua Christian Hospital for curative radiotherapy from 1985 to 1995. The patients were staged according to the AJCC staging system. A mean dose of 7,020 cGy in 39 fractions was delivered to the primary tumor using a telecobalt-60 unit or 6-10 MV X-ray linear accelerator. Pre- and postradiotherapy serum levels of anti-EBV/VCA IgG and IgA were determined for all patients using the indirect immunoperoxidase assay (IPA). Multivariate analysis was done to determine which factors affected the patients' treatment outcome and survival. RESULTS: Five patients were excluded from this study due to incomplete radiotherapy, leaving 75 patients eligible for analysis. Overall local control was 77.3%, with a mean disease-free interval of 19.7 months. Factors affecting local control included radiation dose and pretreatment anti-EBV/VCA IgG titer. The overall 5-year actuarial survival for the 75 patients was 75%, with a median survival of 129.5 months. The 5-year actuarial survival rates for stage I + II, III, and IV patients were 90%, 40%, and 45%, respectively. Prognostic factors for survival included tumor histological type and pretreatment anti-EBV/VCA IgA titer, while prognostic factors for local control included total radiation dose received and pretreatment anti-EBV/VCA IgG titer. CONCLUSION: We found that there was a significant difference in the geometric mean titer of anti-EBV/VCA IgA antibodies before and after radiotherapy. Prognostic factors affecting NPC patients' actuarial survival included tumor histology and pretreatment IgA titer, while prognostic factors for local control of NPC included total radiation dose received and pretreatment IgG titer.