bluuebunny/crossref_metadata_2025 huggingface dataset:
New systems for modeling, estimating, and predicting a multivariate spatio–temporal process
Authors: Haas Timothy C.
Published: October 2002

Two new systems for modeling, estimating, and predicting a multivariate spatio–temporal process are given. In the first system, a cylinder containing a fraction of the multivariate data with axis along the temporal dimension is centered at a spatio–temporal prediction location. After fitting a linear or nonlinear within‐cylinder trend function using minimum distance, an optimal prediction of the observable multivariate process is computed at the cylinder's center. The local nature of this system makes it suited to the analysis of large data sets often associated with ecosystem analyses.

The second system consists of a global model of both the spatio–temporal trend and autocovariance function of the residual process. Each of these is formed by the weighted sum of component global models with weights computed from spatio–temporal kernels centered at each component's most characteristic spatio–temporal location. Minimum distance is again used to estimate all parameters. Predictions are then computed from this fitted global model.

Spatio–temporal autocovariance within and between residual processes is modeled with parametric functions and need not be separable in space and time. The fast Fourier transform is used to approximately verify Hermitian positive semi‐definiteness of the covariogram matrix. Asymmetry of the cross‐covariogram in the temporal dimension is modeled as the sum of parametric even and odd functions. These functions have interpretable parameters. Long temporal memory is also modeled with an interpretable parametric function—obviating the need for fractional differencing across time. These covariance structure models are believed to be new.

The use of a combined John–Draper and Box–Cox transformation allows continuous, count, categorical–ordinal, and categorical–nominal process data to be fitted within the same modeling, estimation, and prediction system, thus allowing mixed continuous–discrete multivariate predictions to be computed that take into account correlations between all constituent processes.

Numerical examples consist of, first, the local system being used to redesign a spatial monitoring network with simulated data, and then both systems being applied to several different real data sets: multivariate spatio–temporal data (prediction of sulfate deposition in the conterminous U.S. with and without nitrate observations), multivariate temporal‐only data (prediction of mink–muskrat pelt counts), and univariate temporal‐only data with long memory (prediction of 5000 years of annual Lake Saki mud thickness). Copyright © 2002 John Wiley & Sons, Ltd.
Kernel method for the estimation of the distribution function and the mean with auxiliary information in ranked set sampling
Authors: Lam K. F. , Yu Philip L. H. , Lee C. F.
Published: October 2002

The method of ranked set sampling is widely applicable in environmental research mainly in the estimation of the mean and distribution function of the variable of interest, Y. Ranking of the Ys by visual judgment may be imperfect sometimes. When the Ys are expensive to measure, it would be more convenient to determine the ‘rankings’ of the Ys by a concomitant variable, X, which is relatively easy and cheap to make measurements. The information carried in X is not utilized in all estimation methods available in the literature except in determining the rankings of Ys unless extra distributional or linearity assumptions are made. However, these assumptions may be too stringent in environmental research. Nonparametric estimators for the distribution function and the mean of Y utilizing the concomitant variable and auxiliary information in a ranked set sampling setup are proposed in this article. The estimators are robust to model misspecification, and the performance of the estimators is highly satisfactory, supported by some simulation studies. The estimators are applied to a real data set to estimate the mean and distribution function of plutonium concentration in surface soil on the Nevada Test Site, Nevada, U.S.A. Copyright © 2002 John Wiley & Sons, Ltd.
Discrete‐time variable structure control method for seismic‐excited building structures with time delay in control
Authors: Cai Guoping , Huang Jinzhi
Published: October 2002

The discrete‐time variable structure control method for seismically excited linear structures with time delay in control is investigated in this paper. The control system with time delay is first discretized and transformed into standard discrete form which contains no time delay in terms of the time delay being integer and non‐integer times of sampling period, respectively. Then the discrete switching surface is determined using ideal quasi‐sliding mode and discrete controller is designed using the discrete approach‐law reaching condition. The deduced controller and switching surface contain not only the current step of state feedback but also linear combination of some former steps of controls. Numerical simulations are illustrated to verify the feasibility and robustness of the proposed control method. Since time‐delay effect is incorporated in the mathematical model for the structural control system throughout the derivation of the proposed algorithm, system performance and dynamic stability are guaranteed. Copyright © 2002 John Wiley & Sons, Ltd.
The influence of groundwater on surface flow erosion processes during a rainstorm
Authors: Rockwell D. L.
Published: October 2002

Surface erosion rates on a disturbed natural soil in a 10 m indoor flume increased by an order of magnitude when a water table developed at a 10 cm depth during simulated rainstorms. Erosion rate increases did not correlate well with surface hydraulic flow conditions, and all significant erosion increases began before the full soil depth was saturated, before the water table reached the soil surface, and before seepage was possible. Groundwater influenced erosion processes primarily by increasing unsaturated pore‐water pressures and decreasing soil shear strength in surface rainflow, rather than through the direct entrainment of soil particles by seepage flow.

There was no unique morphologic expression of the influence of groundwater during a rainstorm. Subsurface processes influencing surface erosion were detected only by appropriate subsurface instrumentation, which included micropiezometers, tensiometers and time domain reflectometry. Erosion rate increases occurred all along the slope, and were not concentrated at the base of slope due to a seepage zone. Soil depth was crucial to determining surface erosion increase. It is likely that confusing trends in surface flow erosion rates in past studies have occurred due to unrecorded groundwater development or an emphasis on seepage effects. Groundwater must be monitored along hillslopes under all moisture and soil conditions in order to avoid misleading and inconsistent conclusions derived solely from surface flow or seepage data. Copyright © 2002 John Wiley & Sons, Ltd.
Overbank sediment deposition patterns for straight and meandering flume channels
Authors: Bathurst J. C. , Benson I. A. , Valentine E. M. , Nalluri C.
Published: October 2002

Experiments with the 10 m Flood Channel Facility at HR Wallingford, UK, indicate a fundamental dependency of the overbank deposition pattern of channel suspended sediments on channel planform. Two experiments (100 and 140 l s−1) in a 1·95 m wide straight channel showed deposition concentrated in a berm along the channel bank. Little sediment was transferred further onto the floodplain. For the larger flow, the berm formed further from the channel. A single experiment (103 l s−1) with a 1·31 m wide meandering channel showed deposition across the entire floodplain tongue between successive meanders. Maximum deposition occurred on the downstream side of the meander, just past the bend apex. These generalized flume results complement the real‐world but site‐specific data of field studies. Copyright © 2002 John Wiley & Sons, Ltd.
A comparison of time integration methods in an unsteady low‐Reynolds‐number flow
Authors: Majander Petri , Siikonen Timo
Published: October 2002

This paper describes three different time integration methods for unsteady incompressible Navier–Stokes equations. Explicit Euler and fractional‐step Adams–Bashford methods are compared with an implicit three‐level method based on a steady‐state SIMPLE method. The implicit solver employs a dual time stepping and an iteration within the time step. The spatial discretization is based on a co‐located finite‐volume technique. The influence of the convergence limits and the time‐step size on the accuracy of the predictions are studied. The efficiency of the different solvers is compared in a vortex‐shedding flow over a cylinder in the Reynolds number range of 100–1600. A high‐Reynolds‐number flow over a biconvex airfoil profile is also computed. The computations are performed in two dimensions. At the low‐Reynolds‐number range the explicit methods appear to be faster by a factor from 5 to 10. In the high‐Reynolds‐number case, the explicit Adams–Bashford method and the implicit method appear to be approximately equally fast while yielding similar results. Copyright © 2002 John Wiley & Sons, Ltd.
An adaptive Cartesian grid generation method for ‘Dirty’ geometry
Authors: Wang Z. J. , Srinivasan Kumar
Published: October 2002

Traditional structured and unstructured grid generation methods need a ‘water‐tight’ boundary surface grid to start. Therefore, these methods are named boundary to interior (B2I) approaches. Although these methods have achieved great success in fluid flow simulations, the grid generation process can still be very time consuming if ‘non‐water‐tight’ geometries are given. Significant user time can be taken to repair or clean a ‘dirty’ geometry with cracks, overlaps or invalid manifolds before grid generation can take place. In this paper, we advocate a different approach in grid generation, namely the interior to boundary (I2B) approach. With an I2B approach, the computational grid is first generated inside the computational domain. Then this grid is intelligently ‘connected’ to the boundary, and the boundary grid is a result of this ‘connection’. A significant advantage of the I2B approach is that ‘dirty’ geometries can be handled without cleaning or repairing, dramatically reducing grid generation time. An I2B adaptive Cartesian grid generation method is developed in this paper to handle ‘dirty’ geometries without geometry repair. Comparing with a B2I approach, the grid generation time with the I2B approach for a complex automotive engine can be reduced by three orders of magnitude. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of neuropsychiatric symptoms of Alzheimer's disease on Chinese and American caregivers
Authors: Pang F. C. , Chow T. W. , Cummings J. L. , Leung V. P. Y. , Chiu H. F. K. , Lam L. C. W. , Chen Q. L. , Tai C. T. , Chen L. W. , Wang S. J. , Fuh J. L.
Published: October 2002

Background

In Chinese culture, extended family support, acceptance of age‐related cognitive changes and filial tradition of caring for elders may decrease caregiver burden and distress in the context of dementia.

Objective

To study cross‐regional and cross‐cultural differences in symptom‐related caregiver distress due to the behavioral problems of Chinese and American patients with Alzheimer's disease.

Method

Caregivers of patients with Alzheimer's disease at Taipei Veterans General Hospital, Taiwan (n = 89), Chinese University of Hong Kong (n = 31) and the UCLA Alzheimer's Disease Research Center, Los Angeles, California (n = 169) reported the neuropsychiatric symptoms of patients and their corresponding distress on the Neuropsychiatric Inventory.

Result

Presence or absence of distress due to the neuropsychiatric symptoms of the patients with Alzheimer's disease was assessed. The three centers differed significantly in the proportions of caregivers with distress caused by depression (p < 0.05) and apathy (p < 0.001). UCLA had higher proportions of caregivers with depression‐related distress than Taipei. UCLA caregivers were also more stressed by apathy than caregivers in Taipei and Hong Kong. Logistic regression further supported the findings that depression‐related and apathy‐related caregiver distress differed between Chinese and American caregivers (p < 0.05).

Conclusions

The results were surprising, in that American and Chinese (Taipei and Hong Kong) caregivers exhibited similar distress or lack of distress in response to delusions, hallucinations, agitation, anxiety, euphoria, disinhibition, irritability, aberrant motor behavior, sleep and appetite symptoms of Alzheimer's disease patients. Chinese caregivers were less affected by depression and apathy in patients with Alzheimer's disease than Caucasian caregivers. Copyright © 2002 John Wiley & Sons, Ltd.
A study of suicides of older people in Sydney
Authors: Snowdon John , Baume Pierre
Published: October 2002

Background

Reports based on studies of coroner's files show that suicides in old age are commonly related to depression, but that in a majority of cases disability or ill‐health is also a major factor. The aim of this study was to try to understand more clearly the precipitant causes of suicide in an older population.

Method

An Australian metropolitan coroner's office provided data concerning suicides in 1994–1998 of persons aged over 65 years.

Results

Of 210 elderly people who killed themselves, 160 (76%) were clearly depressed, including a majority of the 24% deemed to have understandable reasons for suicide. Physical ill‐health or disability was the major factor leading to suicide in 34% and appeared to contribute to suicidal ideation in another 24% of those who died; they had usually not been seen by psychiatrists.

Conclusion

Because depression is often treatable, even when associated with depressing circumstances, there is potential for further reduction of old age suicide rates by recognising and appropriately responding to symptoms of depression and distress. Copyright © 2002 John Wiley & Sons, Ltd.
A 24‐week, double‐blind, placebo‐controlled trial of donepezil in patients with Down syndrome and Alzheimer's disease—pilot study
Authors: Prasher Vee. P. , Huxley Adam , Haque M. S. ,   the Down syndrome Ageing Study Group
Published: October 2002

Background

Donepezil Hydrochloride (Aricept) is a selective anticholinesterase inhibitor developed for the treatment of Alzheimer's disease (AD). This study investigated the safety and efficacy of the drug to treat Down syndrome (DS) adults with mild to moderate AD.

Method

This was a 24‐week, double blind, placebo controlled, parallel‐group trial. Patients were randomized to receive placebo or donepezil (5 mg per day during the first four weeks, and then 10 mg per day thereafter). Primary efficacy was measured using the Dementia Scale for Mentally Retarded Persons (DMR), and secondary efficacy was measured using the Severe Impairment Battery (SIB), Neuropsychiatric Inventory (NPI) and by the Adaptive Behavior Scale (ABS).

Results

A total of 30 DS patients with AD entered the study of which 27 were included in the subsequent data analysis. The donepezil group had non‐statistically significant reduction in deterioration in DMR, SIB, and ABS mean scores relative to the placebo group. However NPI scores showed less improvement in the donepezil group when compared to the placebo group. Fifty percent of subjects in the donepezil group showed improvement in mean DMR scores at the end point compared to baseline, when compared to 31% on placebo. There were no life threatening adverse effects associated with treating adults with DS with donepezil. A number of side‐effects did occur including diarrhoea, insomnia, fatigue, and nausea.

Conclusion

Donepezil Hydrochloride administered once a day appears to be generally well tolerated and safe in DS adults who have AD. There is some possible efficacy in the treatment of symptoms of mild to moderate Alzheimer's disease in this population, although the sample size of this study was too small for statistical significance. It is recommended that donepezil, with the appropriate precautions, should be considered for the treatment of AD in adults with DS as deemed by a specialist. Copyright © 2002 John Wiley & Sons, Ltd.
Geriatric Depression Scale Scores in a representative sample of 14 545 people aged 75 and over in the United Kingdom: results from the MRC Trial of Assessment and Management of Older People in the Community
Authors: Osborn David P. J. , Fletcher Astrid E. , Smeeth Liam , Stirling Susan , Nunes Maria , Breeze Elizabeth , Siu‐Woon Edmond , Bulpitt Christopher J. , Jones Dee , Tulloch Alistair
Published: October 2002

Background

An Erratum has been published for this article in International Journal of Geriatric Psychiatry 17(6) 2002, 592.

The 15‐item Geriatric Depression Scale (GDS‐15) is recommended for screening older people, but there are no large epidemiological studies using this instrument in the UK. We describe the age and sex distribution of GDS‐15 scores in the largest ever UK sample of people aged 75 and over.

Method

We used cross‐sectional data from the MRC Trial of the Assessment and Management of Older People in the Community. The GDS‐15 was offered to a representative sample of UK people aged 75 and over. Proportions of people attaining thresholds on the GDS‐15 were calculated by age group and sex. Crude Odds ratios (ORs) for the effect of age and sex were calculated and the sex/age adjusted ORs estimated using logistic regression for surveys, at three GDS‐15 thresholds.

Results

Of 21 241 (71.2%; 95% Confidence intervals (CI): 67.9–74.3) eligible people, 15 126 received the assessment including the GDS‐15. Of these, 14 545 (96.2%; 94.7–97.2) completed ≥13 GDS‐15 answers and were included in the study. Scores showed a marked right skew, with a median of 2 (interquartile range: 1–3; range: 0–14). 34.6% (95% CI: 32.1–37.3) people scored ≥3, 8.0% (6.9–9.2) scored ≥6 and 3.1% (2.5–3.7) scored ≥8. Women were significantly more likely to score above all three thresholds than men, as were older participants.

Conclusions

Depression may be common in later life. The data provide a national picture of the numbers of older people who will score positively for depression in health screens which include the GDS‐15, as recommended by the Royal College of General Practitioners. Copyright © 2002 John Wiley & Sons, Ltd.
Wisconsin card sorting test synchronizes the prefrontal, temporal and posterior association cortex in different frequency ranges and extensions
Authors: González‐Hernández José Alberto , Pita‐Alcorta Concepción , Cedeño Iluminada , Bosch‐Bayard Jorge , Galán‐Garcia Lídice , Scherbaum Werner A. , Figueredo‐Rodriguez Pedro
Published: October 2002

Current findings show some brain regions consistently related to performance of the Wisconsin Card Sorting Test (WCST). An increase of local cerebral blood flow or metabolic demands has been detected in those regions. Functional integration of the neuronal circuits that subserve the task performance, based upon the identification of the oscillations and their distributed cerebral sources, has not been accomplished previously. The event‐related tonic oscillations within a period of 2,000 msec after the stimulus onset and the probable neural substrate were evaluated in healthy volunteers by variable‐resolution brain electrical tomography (VARETA). The WCST induced a significant increase of δ, θ, β‐2, and γ oscillations, but decrease of α. Areas such as the frontal subregions, temporal, cingulate, parahippocampal, parietal, occipitotemporal cortex, and occipital poles showed modified activity during the task, with EEG spectral band selectivity as well as some overlapping among them. Frontal and temporal regions generated the δ/θ oscillations. Additionally, the occipitotemporal and parietal regions were the source of the δ activity, lacking θ activation. The parietal region also showed tonic α, β‐2 and γ changes. These data imply that different processes have been simultaneously mediated during task performance. Relationships among the individual bands, the neural substrata and the specific cognitive process that support the task were established. The selectively distributed δ, θ, α, β‐2 and γ oscillations reflect communication networks through variable populations of neurons, with functional relations to the working memory functions and the information processing that subserve the WCST performance. Hum. Brain Mapping 17:37–47, 2002. © 2002 Wiley‐Liss, Inc.
Differentiated thyroid carcinoma: Comparison between papillary and follicular carcinoma in a single institute
Authors: Chow Sin‐Ming , Law Stephen C. K. , Au Siu‐Kie , Leung To‐Wai , Chan Paddy T. M. , Mendenhall William M. , Lau Wai‐Hon
Published: October 2002

Purpose

To compare and contrast the clinical presentation and treatment outcome of patients with papillary and follicular thyroid carcinoma and to study the pattern of practice of treatment of differentiated thyroid carcinoma in Hong Kong.

Method

The clinical presentation and treatment outcomes were reviewed for 1057 patients with differentiated thyroid cancers who were treated at the Queen Elizabeth Hospital, Hong Kong, from 1960 to 1997. Eight hundred forty‐two patients had papillary thyroid carcinomas (PTC), and 215 had follicular thyroid carcinomas (FTC). The mean follow‐up was 9.2 years.

Results

The differences in the clinical factors of PTC to FTC were as follows: PTC had a higher incidence (3.9:1); these patients were younger at presentation (median age, 44 vs 49), showed a higher female–male ratio (4.5 vs 2.9) and smaller primary tumor size (median 2 cm vs 3.5 cm), and a higher incidence of multifocal disease (28.3% vs 18.1%), extrathyroidal extension (39.4% vs 14%), and more lymph node metastases (33.3% vs 12.1%). The incidence of distant metastases was higher for patients with FTC (28.8% vs 8.9%), and cause‐specific survival rates were lower (p= .001). The locoregional control rates were not significantly different (p= .2). The 10‐year cause‐specific survival, freedom from distant metastasis, and locoregional failure figures for PTC compared with FTC were 92.1% vs 81%, 90.8% vs 72.3%, and 78.5% vs 83%.

Conclusions

Although patients with PTC tend to have more advanced locoregional disease compared with those with FTC, the likelihood of locoregional control is similar, and the probability of cure is better. © 2002 Wiley Periodicals, Inc. Head Neck 24: 670–677, 2002
Supracricoid partial laryngectomy as salvage surgery after radiation failure
Authors: Spriano Giuseppe , Pellini Raul , Romano Guglielmo , Muscatello Luca , Roselli Raffaele
Published: October 2002

Background

Radiotherapy is often chosen as the definitive treatment for early stage laryngeal carcinoma. Total laryngectomy is the main procedure for failures. Endoscopic treatment of recurrences by CO2laser has found limited application. Partial laryngectomy through an external approach has been proposed as salvage surgery, and the vertical partial laryngectomy (VPL) is the most mentioned surgical technique in the literature, although there are, to date, very few reports regarding the use of the supracricoid partial laryngectomy (SCPL) as salvage surgery after radiation failure.

Objectives

The aim of the study is to check the feasibility of SCPL with cricohyoidoepiglottopexy (CHEP) or cricohyoidopexy (CHP) in patients with laryngeal recurrence after radiation failure and to evaluate the oncologic results, morbidity, and functional outcome.

Methods

Fifteen consecutive patients were treated with salvage intent by SCPL from January 1992 to December 1998. CHEP and CHP were performed in 11 and 4 patients, respectively. Five patients underwent homolateral surgical neck dissection, and one underwent bilateral neck dissection. All patients had a temporary tracheostomy, and two patients required percutaneous endoscopic gastrostomy (PEG) to ensure feeding. Functional rehabilitation started 2 weeks after the operation.

Results

The results have been evaluated in terms of oncologic outcome and functional preservation. Twelve patients are alive with a minimum follow‐up of 36 months and 3 patients died after 36 days, 6 and 14 months after surgery, the first and second patient from heart failure and the third from lung metastasis. Respiratory function was recovered in all cases. Oral intake began 12 days after surgery, and in 14 cases satisfactory swallowing was recovered 30 days after surgery. An acceptable quality of the voice was achieved by most patients, and a high rate of local immediate complications was solved in all cases.

Conclusions

SCPL represents an effective technique as salvage treatment of laryngeal cancer after exclusive radiotherapy; there is a good functional recovery with acceptable morbidity and good oncologic long‐term control. © 2002 Wiley Periodicals, Inc. Head Neck 24: 759–765, 2002
A postural workload evaluation system based on a macro‐postural classification
Authors: Chung Min K. , Lee Inseok , Kee Dohyung , Kim Sang H.
Published: October 2002

Many Korean workers are exposed to repetitive or prolonged poor working postures, which are closely related with pains or symptoms of musculoskeletal disorders. Poor working postures in Korea were reviewed and an observational method to assess the postural load was developed. A computer‐based postural workload evaluation system based on a macro‐postural classification scheme was developed. The macro‐postural classification is based on the perceived discomforts for various joint motions. On the basis of the perceived discomfort, postural stress levels for the postures at each joint were also defined in a ratio scale to the standing neutral posture. A neural network approach was used to predict the whole‐body postural stresses from the body joint motions. A computer‐based postural stress evaluation system was designed to automate the procedure for analyzing postures and enhance the usability and practical applicability. © 2002 Wiley Periodicals, Inc.
Fluid flow and heat transfer of natural convection at a slightly inclined, upward‐facing, heated plate
Authors: Kimura Fumiyoshi , Yoshioka Tetsuji , Kitamura Kenzo , Yamaguchi Manabu , Asami Toshihiko
Published: October 2002

Natural convective flows over upward‐facing, inclined plates were investigated experimentally, with an emphasis on the role of opposing flows that appear over the plates inclined slightly from the horizontal line. The flow fields over the plates and the surface temperatures of the heated plates were visualized with both dye and a liquid‐crystal thermometry. The results showed that both the descending and ascending flows appeared over the plates when the inclination angles of the plates were less than 15°. The two flows collided with each other at a certain distance from the plate edge, and then detached from the plate to become a thermal plume. It was found that the above distance was determined solely by the inclination angles and was independent of sizes and heat fluxes of the plates. The local heat transfer coefficients of the plates were also measured. The results showed that the heat transfer from the plate was enhanced by the occurrence of the descending flows. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(5): 362–375, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10036
Psychomotor performance of psychiatric inpatients under therapy: assessment by paper and pencil tests
Authors: Agarwal A. K. , Kalra R. , Natu M. V. , Dadhich A. P. , Deswal R. S.
Published: October 2002

Fifty psychiatric inpatients included in the study were diagnosed as having substance related disorder, schozophrenia, bipolar disorder, depressive disorder or anxiety disorder based on DSM‐IV and ICD‐10. All the patients were on multiple drug therapy for a minimum of 7 days in the hospital. The psychomotor performance score assessed with the help of the six letter cancellation test and the digit letter substitution test was compared with a matched group of 50 normal volunteers. The significantly low scores for patients may be considered indicative of the fact that prolonged therapy would be required to attain normal psychomotor status. Thus, simple paper and pencil tests may provide valuable information in assessment of psychomotor and cognitive functions of psychiatric patients during recovery. Copyright © 2002 John Wiley & Sons, Ltd.
Ecstasy/MDMA attributed problems reported by novice, moderate and heavy recreational users
Authors: Parrott A. C. , Buchanan T. , Scholey A. B. , Heffernan T. , Ling J. , Rodgers J.
Published: October 2002

Rationale

The recreational use of MDMA/Ecstasy (3,4‐methylenedioxymethamphetamine) is associated with many psychobiological problems, but there is a paucity of data on how these relate to the level of past use. Objectives: to assess the incidence of Ecstasy‐attributed problems as reported by novice, moderate and heavy users. Methods: 763 unpaid volunteers took part in a WWW study of recreational drug use. This report is based on the 282 Ecstasy users from that sample, who comprised 109 novice users (1–9 occasions), 136 moderate users (10–99 occasions), and 36 heavy users (+100 occasions). Yes/no responses were automatically recorded to a series of questions covering psychobiological problems experienced when drug‐free, which were attributed by the respondents to their Ecstasy use. Results: Depression, memory problems, anxiety, mood fluctuation, poor concentration, infections, tremors/twitches and weight loss, were all significantly associated with the extent of Ecstasy use. Thus memory problems attributed to Ecstasy were reported by 19% of novice users, 52% of heavy users and 73% of heavy users (chi‐square 42.74, df=2, p<0.001); many of the other variables showed similar trends.

Conclusions

The incidence of problems attributed to Ecstasy use, is directly related to the number of occasions it has been used. Copyright © 2002 John Wiley & Sons, Ltd.
Risk assessment for optimal drought management of an integrated water resources system using a genetic algorithm
Authors: Merabtene Tarek , Kawamura Akira , Jinno Kenji , Olsson Jonas
Published: October 2002

A decision support system (DSS) is developed and applied to assess the susceptibility of water supply systems to droughts, and to aid decision‐makers in determining optimal supply strategies. The DSS integrates three fundamental modules for water resources management: (1) a real time rainfall‐runoff forecasting model enhanced by Kalman filtering; (2) a water demand forecast model; and (3) a reservoir operation model. Simulation and optimization procedures for the reservoir operation model are based on risk analysis to evaluate the system performance and to derive the most appropriate supply strategy of minimum risk, for the designed operating conditions. The optimization technique, based on genetic algorithms, introduces two new and distinct features, with the aim of minimizing the risks of drought damage and improving the convergence of the model toward practical solutions. Firstly, risk‐based measures of system performance, termed reliability, resiliency and vulnerability, are combined into a global risk index, referred to as the drought risk index (DRI). The DRI, formulated as a weighted function of the risk measures, serves as the objective function to be minimized during the search for the optimal operation. Secondly, in the genetic algorithm search, each new generation of water supply solutions is created from solutions with risk levels clustered inside a defined ‘acceptable risk space’. In other words, the convergence of the algorithm is improved by retaining only those solutions with DRI values smaller than the maximum acceptable risk. As a case study, the DSS is applied to the water resources system in Fukuoka City, western Japan. The DSS is believed to be an efficient tool for the assessment of a sequence of water supply scenarios, leading to the improved utilization of existing water resources during drought. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of the duration and direction of storm movement on infiltrating planar flow with full areal coverage
Authors: Singh V. P.
Published: October 2002

Using kinematic wave equations, analytical solutions are derived for flow due to a storm moving up or down an infiltrating plane and covering it completely. The storm duration is assumed in two ways. First, the plane is covered everywhere for the same duration by the storm. Second, the plane is covered in a linearly decreasing manner from the beginning of its coverage of the plane to the other end of the plane. By comparing the flow due to this storm with that due to a stationary storm of the same duration, the influence of storm duration, direction and velocity on flow hydrograph is investigated. It is found that storm movement has a pronounced effect on runoff hydrograph. Copyright © 2002 John Wiley & Sons, Ltd.
Cigarette smoking and breast cancer risk: A long latency period?
Authors: Terry Paul D. , Miller Anthony B. , Rohan Thomas E.
Published: October 2002

The association between cigarette smoking and breast cancer risk remains unclear. Few studies have examined cigarette smoking of very long duration as there may not have been a sufficient number of long‐term smokers in studies conducted before the 1980s. Therefore, we examined the association between smoking and breast cancer risk using data from participants in a randomized controlled trial of screening for breast cancer involving 89,835 women aged 40–59 years at recruitment and with up to 40 years of smoking duration at that time. Women with breast cancer diagnosed through 31 December 1993 were identified by linkage to the Canadian Cancer Database. Cox proportional hazards models were used to estimate rate ratios (RRs) and 95% confidence intervals (CIs). During an average of 10.6 years of follow‐up, we observed 2,552 incident cases of breast cancer. We found a positive association between cigarette smoking and breast cancer risk, driven mainly by women who had smoked for several decades and who, therefore, had commenced smoking many years earlier. Relative to never‐smokers, women who had smoked 40 years or more and 20 cigarettes/day or more were at the highest risk (RR = 1.83, 95% CI 1.29–2.61); for women who had commenced smoking 40 years or more before assessment (a measure of smoking latency rather than duration and intensity), the RR was 1.22 (95% CI 0.99–1.59). Our findings suggest that smoking of very long duration and high intensity may be associated with increased risk of breast cancer. © 2002 Wiley‐Liss, Inc.
The chick chorioallantoic membrane as a novel in vivo model for the testing of biomaterials
Authors: Valdes T.I. , Kreutzer D. , Moussy F.
Published: October 2002

Current in vivo models for testing biomaterials are time and labor intensive as well as expensive. This article describes a new approach for testing biomaterials in vivo using the chorioallantoic membrane (CAM) of the developing chicken embryo, as an alternative to the traditional mammalian models. Fertilized chicken eggs were incubated for 4 days, at which time a small window was cut in the shell of the egg. After 1 week of incubation, the CAM received several test materials, including the endotoxin LPS, a cotton thread and a Silastic tubing. One day and 1 week later, the tissue response to the test materials was assessed using gross, histological, and scanning electron microscope evaluations. The inflammatory response of the chorioallantoic membrane to biomaterials was fully characterized and found to be similar to that of the mammalian response and was also seen to vary according to test materials. We also found that the structure and geometry of the test materials greatly influenced the incorporation of the samples in the CAM. The similarity of the tissue response of the CAM with the mammalian models, plus the low cost, simplicity, and possibility to continuously visualize the test site through the shell window make this animal model particularly attractive for the rapid in vivo screening of biomaterials. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 273–282, 2002
Effects of substratum surface topography on the organization of cells and collagen fibers in collagen gel cultures
Authors: Glass‐Brudzinski J. , Perizzolo D. , Brunette D. M.
Published: October 2002

This study investigated the orientation of fibroblasts and collagen cultured on microfabricated grooved or smooth titanium surfaces, as well as on tissue culture polystyrene, in the presence or absence of collagen gels. The gels were first added either to the confluent fibroblast culture on the surface (cell–gel condition) or to the fibroblasts were suspended within the collagen gel and then placed onto the surface (gel condition). Cells and collagen were observed with differential interference, polarization, and confocal laser scanning microscopy. Although the smooth surfaces had no effect on cell orientation in the gel for the first 2 weeks of culture, cells did orient with grooves regardless of the culture conditions. There was evidence for orthogonal multilayering of cells under the cell–gel condition at 4 weeks, and collagen alignment reflected cell alignment. The interaction of the collagen gel with the surface depended on whether the cell–gel or the gel condition was employed. In the former condition, the gel contracted toward the substratum, whereas the gel condition resulted in the formation of a ring of collagen loosely attached to the substratum. These results suggest that the order in which fibroblasts encounter substratum and extracellular matrix can influence the eventual matrix–cell interactions, and that substratum topography can influence matrix and cell orientation in zones not immediately in contact with the surface. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 608–618, 2002
In vivo drug distribution dynamics in thermoablated and normal rabbit livers from biodegradable polymers
Authors: Gao Jinming , Qian Feng , Szymanski‐Exner Agata , Stowe Nicholas , Haaga John
Published: October 2002

Image‐guided radiofrequency ablation combined with intratumoral drug delivery provides a novel and minimally invasive treatment of liver cancers. In this study, the in vivo transport properties of doxorubicin in thermoablated and nonablated rabbit livers were characterized and compared. Doxorubicin was released from polymer implants (millirods) to the ablated and nonablated liver tissue. At different time points, the 2D distribution profiles were quantitatively determined by a fluorescence imaging method. Analysis of the doxorubicin concentration at the ablation boundary showed that it reached a maximum of 49.8 μg/g at 24 h after implantation, which was higher than the reported cytotoxic concentration of doxorubicin (6.4 μg/g) for liver VX‐2 cancer cells. This value dropped to 0.4 μg/g at 48 h after implantation due to the depletion of doxorubicin from the polymer millirod. Results also showed that the area of drug distribution was significantly larger in ablated tissue than nonablated tissue. The therapeutic penetration distance was found to be 5.2 mm in thermoablated livers, compared to 1.2 mm in nonablated livers at 24 h. This difference in drug transport properties is attributed to destruction of the vasculature network in the ablated tissue as supported by histological analysis. Consequently, drug washout by blood perfusion is hampered while drug diffusion becomes the dominant process of transport in the ablated tissue. Results from this study provide insightful information on the rational design and development of polymer millirods for intratumoral drug delivery applications. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 308–314, 2002
Long‐term treatment of myasthenia gravis with immunoadsorption
Authors: Haas Martin , Mayr Norbert , Zeitlhofer Josef , Goldammer Andreas , Derfler Kurt
Published: October 2002

Acute treatment of myasthenic crisis with immunoadsorption (IA) or plasma exchange is well established. The efficiency of chronic apheresis therapy in myasthenia gravis (MG), however, and its efficacy in reducing concomitant potentially harmful immunosuppressive therapy, is unknown. We treated 13 patients with therapy‐resistant MG or severe steroid or azathioprine therapy‐related side effects, or both, with long‐term IA [median, 38 (range: 16–59) months]. IA was performed every second day until partial remission was achieved (modified Osserman score <2). Subsequently, oral immunosuppressive therapy was reduced and the frequency of IA adapted to the clinical symptoms. After initiation of IA the mean (SEM) Osserman score decreased from 3.23 ± 0.12 to 1.23 ± 0.08 within 1 month (P < 0.01). Mean azathioprine dose was reduced concomitantly from 89 ± 9.4 mg/day to 56 ± 11 mg/day (P < 0.05), and mean prednisolone dose from 41 ± 7.6 mg/day to 22 ± 8.5 mg/day (P < 0.05). After 36 months the number of IA‐sessions/month had been reduced from 4.81 ± 0.24 to 2.64 ± 0.4 (P < 0.05), the mean azathioprine dose to 25 ± 17 mg/day and the mean prednisolone dose to 9 ± 3.6 mg/day. Six out of thirteen patients were weaned from IA after a median of 33 (range, 16–50) months and a decrease of the Osserman score to 0.33 ± 0.33. In these patients MG remained stable during a follow‐up period of 28 (range, 16–38) months. We conclude that long‐term IA enables the reduction of oral immunosuppressants in patients with contraindications or resistance to steroid and azathioprine therapy. Furthermore, almost 50% of the patients can be weaned from IA with then substantial lower need of further immunosuppressive therapy. J. Clin. Apheresis 17:84–87, 2002. © 2002 Wiley‐Liss, Inc.
1,25(OH)2‐vitamin D3 induces translocation of the vitamin D receptor (VDR) to the plasma membrane in skeletal muscle cells
Authors: Capiati Daniela , Benassati Silvia , Boland Ricardo L.
Published: October 2002

1,25‐dihydroxy‐vitamin D3 (1,25(OH)2D3), the hormonally active form of vitamin D3, acts through two different mechanisms. In addition to regulating gene expression via the specific intracellular vitamin D receptor (VDR), 1,25(OH)2D3 induces rapid, non‐transcriptional responses involving stimulation of transmembrane signal transduction pathways. The activation of second messengers supports the hypothesis that a membrane‐bound steroid receptor similar to those that mediate peptide hormone biology exists. Skeletal muscle is a target tissue for 1,25(OH)2D3. Avian embryonic skeletal muscle cells (myoblasts/myotubes) have been shown to respond both genomically and non‐genomically to the hormone. The present study provides evidence indicating that short‐term treatment (1–10 min) with 1,25(OH)2D3 induces translocation of the VDR from the nuclear to the microsomal fraction in chick myoblasts. This translocation is blocked by colchicine, genistein, or herbimycin, suggesting the involvement of microtubular transport and tyrosine kinase/s in the relocation of the receptor. By isolation of plasma membranes, it was demonstrated that the hormone increases the amounts of VDR specifically in this fraction. These results suggest that the nuclear VDR may be the receptor that mediates the non‐genomic effects of 1,25(OH)2D3 in chick myoblasts. J. Cell. Biochem. 86: 128–135, 2002. © 2002 Wiley‐Liss, Inc.
Retinoid X receptors and retinoid response in neuroblastoma cells
Authors: Rana Birju , Veal Gareth J. , Pearson Andrew D.J. , Redfern Christopher P.F.
Published: October 2002

Retinoic acid (RA) modulates differentiation and apoptosis of neural cells via RA receptors (RARs) and retinoid X receptors (RXRs). Neuroblastoma cells are potentially useful models for elucidating the molecular mechanisms of RA in neural cells, and responses to different isomers of RA have been interpreted in terms of differential homo‐ and heterodimerization of RXRs. The aim of this study was to identify the RXR types expressed in neuroblast and substrate‐adherent neuroblastoma cells, and to study the participation of these RXRs in RAR heterodimers. RXRβ was the predominant RXR type in N‐type SH SY 5Y cells and S‐type SH EP cells. Gel shift and supershift assays demonstrated that RARβ and RARγ predominantly heterodimerize with RXRβ. In SH SY 5Y cells, RARγ/RXRβ was the predominant heterodimer binding to the DR5 RARE in the absence of 9‐cisRA (9C), whereas the balance shifted in favor of RARβ/RXRβ in the presence of ligand. There was a marked difference between the N‐ and S‐type neuroblastoma cells in retinoid receptor–DNA interactions, and this may underlie the differential effects of retinoids in these neuroblastoma cell types. There was no evidence to indicate that 9C functions via RXR homodimers in either SH SY 5Y or SH EP neuroblastoma cells. The results of this study suggest that interactions between retinoid receptors and other nuclear proteins may be critical determinants of retinoid responses in neural cells. © 2002 Wiley‐Liss, Inc.
Metallothionein is required for zinc‐induced expression of the macrophage colony stimulating factor gene
Authors: Kanekiyo Masako , Itoh Norio , Kawasaki Atsuko , Matsuda Kimihiro , Nakanishi Tsuyoshi , Tanaka Keiichi
Published: October 2002

Macrophage colony stimulating factor (M‐CSF) plays an important role in the proliferation and differentiation of mononuclear phagocytes. The present study investigates the effect of zinc on M‐CSF expression in MC3T3‐E1 and L929 cells. Zinc dose‐dependently increased M‐CSF mRNA levels. The time‐course of zinc‐induced M‐CSF mRNA expression peaked at 6 h. Stability studies of mRNA using actinomycin D revealed that zinc does not affect M‐CSF mRNA stability. We examined the function of the M‐CSF gene promoter using a luciferase reporter assay. A construct containing the −467/+39 region of the promoter was upregulated by zinc. In the presence of cycloheximide, zinc did not induce a greater increase in the M‐CSF mRNA than cycloheximide alone. To confirm the effect of MT on M‐CSF mRNA expression, mouse lung fibroblasts (MLFs) were prepared from MT+/+ and MT−/− mice. Zinc induced an increase in the expression of M‐CSF in MT+/+ MLFs, but this response was not evident in MT−/− MLFs. Moreover, overexpression of MT upregulated M‐CSF mRNA expression as well as M‐CSF secretion. Our findings suggest that MT expression mediates zinc regulation of M‐CSF gene expression at the transcriptional level. J. Cell. Biochem. 86: 145–153, 2002. © 2002 Wiley‐Liss, Inc.
Role of GST P1‐1 in mediating the effect of etoposide on human neuroblastoma cell line Sh‐Sy5y
Authors: Bernardini S. , Bellincampi L. , Ballerini S. , Ranalli M. , Pastore A. , Cortese C. , Federici G.
Published: October 2002

The oxidative stress could have a dual action on glutathione S‐transferase (GST) P1‐1 metabolism: transcriptional induction and/or polymerization. The former should represent a form of adaptation to oxidative stress and contribute to protect the cell, the latter one should activate apoptosis via c‐Jun N‐terminal kinase (JNK). We studied the effect of etoposide on human neuroblastoma cell line SH‐SY5Y and on an etoposide‐resistant clone to investigate whether a pleiotropic effect of etoposide on the redox status of the cell exists which is able to interfere with apoptosis through the GST P1‐1 system. Etoposide treatment was able to induce GST P1‐1 polymerization and activation of apoptosis. The data obtained from our etoposide‐resistant clone and the possibility to reverse the sensitive phenotype to a resistant one by means of hexyl‐glutathione preincubation, seem to suggest that cellular levels of glutathione have a key role in protecting GST P1‐1 by oxidation and consequently the cell's decision between life and death. J. Cell. Biochem. 86: 340–347, 2002. © 2002 Wiley‐Liss, Inc.