bluuebunny/crossref_metadata_2025 huggingface dataset:
Cortical sources of the early components of the visual evoked potential
Authors: Di Russo Francesco , Martínez Antígona , Sereno Martin I. , Pitzalis Sabrina , Hillyard Steven A.
Published: August 2002

This study aimed to characterize the neural generators of the early components of the visual evoked potential (VEP) to isoluminant checkerboard stimuli. Multichannel scalp recordings, retinotopic mapping and dipole modeling techniques were used to estimate the locations of the cortical sources giving rise to the early C1, P1, and N1 components. Dipole locations were matched to anatomical brain regions visualized in structural magnetic resonance imaging (MRI) and to functional MRI (fMRI) activations elicited by the same stimuli. These converging methods confirmed previous reports that the C1 component (onset latency 55 msec; peak latency 90–92 msec) was generated in the primary visual area (striate cortex; area 17). The early phase of the P1 component (onset latency 72–80 msec; peak latency 98–110 msec) was localized to sources in dorsal extrastriate cortex of the middle occipital gyrus, while the late phase of the P1 component (onset latency 110–120 msec; peak latency 136–146 msec) was localized to ventral extrastriate cortex of the fusiform gyrus. Among the N1 subcomponents, the posterior N150 could be accounted for by the same dipolar source as the early P1, while the anterior N155 was localized to a deep source in the parietal lobe. These findings clarify the anatomical origin of these VEP components, which have been studied extensively in relation to visual‐perceptual processes. Hum. Brain Mapping 15:95–111, 2001. © 2001 Wiley‐Liss, Inc.
Multiresolution analysis in fMRI: Sensitivity and specificity in the detection of brain activation
Authors: Desco M. , Hernandez J.A. , Santos A. , Brammer M.
Published: August 2002

Multiresolution analysis of fMRI studies using wavelets is a new approach, previously reported to yield higher sensitivity in the detection of activation areas. No data are available, however, in the literature on the analytic approach and wavelet bases that produce optimum results. The present study was undertaken to assess the performance of different wavelet decomposition schemes by making use of a “gold standard,” a realistic computer‐simulated phantom. As activation areas are then known ‘a priori,’ accurate assessments of sensitivity, specificity, ROC curve area and spatial resolution can be obtained. This approach has allowed us to study the effect of different factors: the size of the activation area, activity level, signal‐to‐noise ratio (SNR), use of pre‐smoothing, wavelet base function and order and resolution level depth. Activations were detected by performing t‐tests in the wavelet domain and constructing the final image from those coefficients that passed the significance test at a given P‐value threshold. In contrast to previously reported data, our simulation study shows that lower wavelet orders and resolution depths should be used to obtain optimum results (in terms of ROC curve area). The Gabor decomposition offers the maximum fidelity in preserving activation area shapes. No major differences were found between other wavelet bases functions. Data pre‐smoothing increases ROC area for all but very small activation region sizes. Hum. Brain Mapping 14:16–27, 2001. © 2001 Wiley‐Liss, Inc.
On the empirical association between poor health and low socioeconomic status at old age
Authors: Salas Christian
Published: August 2002

Epidemiologic studies using mortality rates as indicators of health fail to find any meaningful association between poor health and low socioeconomic status in older age‐groups, whereas economic studies using self‐assessed health consistently find a significant positive correlation, even after controlling for self‐reporting errors. Such contradictory results have not been reported for working age individuals. A simple explanation might be that the elderly samples on which the epidemiologic and economic studies are based come from different populations. However, this paper shows that similar contradictory results are obtained even whenthe same samplesare used, simply by switching between self‐assessed health and mortality as health indicators. An alternative explanation is proposed, namely that these health indicators yield different results because they relate to different ranges of the latent health variable at old age. Copyright © 2002 John Wiley & Sons, Ltd.
Radiosurgery for paraganglioma of the temporal bone
Authors: Feigenberg Steven J. , Mendenhall William M. , Hinerman Russell W. , Amdur Robert J. , Friedman William A. , Antonelli Patrick J.
Published: August 2002

Purpose

To report the outcome of patients with paraganglioma of the temporal bone treated with stereotactic radiosurgery at the University of Florida.

Methods and Materials

Between January 1997 and June 1999, five patients with paraganglioma of the temporal bone were treated with Linac‐based stereotactic radiosurgery at the University of Florida. The ages of the three female and two male patients were between 40 and 88 years (median, 49 years). Four patients were treated at initial presentation, and one had recurrent disease. Treatment volumes ranged from 4.9 cm3 to 18.4 cm3, with a mean of 10.84 cm3. The dose applied to the margin of the tumor varied from 12.5 to 15 Gy (median, 15 Gy). The treatment dose was specified to the 80% isodose shell in two cases and to the 70% isodose shell in three cases. The median follow‐up time was 27 months, ranging from 14 to 50 months.

Results

One of four previously untreated patients had a relapse at the primary tumor site. Treatment failure occurred at the field margin 6 months after radiosurgery; the patient was subsequently treated with fractionated stereotactic radiotherapy and at the time of analysis had no evidence of disease, 21 months after initiation of salvage therapy. The patient treated at the time of recurrence after conventional radiotherapy had a local recurrence 40 months after radiosurgery. At the time of this recurrence, the patient had biopsy‐proven metastatic disease in two cervical lymph nodes, and no salvage therapy was performed. All patients were alive at the time of the analysis, one with disease present. Presenting symptoms improved in two patients and stabilized in one. The two patients who had local recurrence develop had worsening of their symptoms. One patient had a cranial nerve V palsy develop 6 months after treatment, which resolved after a few months.

Conclusions

In this series, the results with stereotactic radiosurgery are discouraging compared with our results with conventional fractionated radiotherapy in patients with paraganglioma of the temporal bone. © 2002 Wiley Periodicals, Inc. Head Neck 24: 384–389, 2002; DOI 10.1002/hed.10064
New work councils: Expanded cooperation in the public sector in Denmark
Authors: Mathiesen Karin , Hvenegaard Hans
Published: August 2002

This article discusses several pilot projects carried out by Danish state institutions between 1995 and 1998 to extend employee participation through changes in the structure, competencies, and task areas within workplace work councils and safety organizations. In extending these projects, the employers and employees' organizations agreed in 1999 to prolong the existing cooperative agreement as well as a framework agreement that allows for new ways to organize cooperation and safety activities. The article discusses these initiatives and raises a series of questions about the possibilities and difficulties connected with increased employee participation. © 2001 John Wiley & Sons, Inc.
Goal orientation and practice condition as predictors of training results
Authors: Hertenstein Edward J.
Published: August 2002

This study examines the training outcomes related to the interaction between the motivational factor of learning goal orientation and the situational factor of practice distribution. Participants in weekly (spaced) and residential (massed) labor education classes were assessed at the beginning of training for cognitive ability and learning goal orientation. At the end of training, declarative knowledge and task‐specific self‐efficacy were examined as outcomes. Contrary to expectations, it was found that individuals with high learning goal orientation had more positive outcomes in the massed practice course than in the spaced practice course.
Effect of tabs on impinging heat transfer
Authors: Hiwada Munehiko , Tanaka Shintarou , Tanaka Kouzou , Oyakawa Kenyu
Published: August 2002

The present work experimentally investigates the effect of vortex generators, in the form of small tabs projecting normally into the flow at the nozzle exit, on the fluid flow and heat transfer characteristics of an axisymmetric impinging air jet in the subcritical Reynolds number range. With this comes the expectation of a large eddy structure variation and the possibility of active control. Local heat transfer and static pressure were measured on a target plate for a round air jet issuing from a circular nozzle with rectangular tabs whose numbers and lengths changed at a constant nozzle‐to‐plate gap (L/d= 8) and jet Reynolds number (Re= 34,000). The main results are the following: When two tabs were set at the exit of the circular nozzle,CpwandNuprofiles flatten in the direction of the tab setting. In the case of three tabs, however, among bothCpwandNuprofiles a concentric profile is found, as well as in the case without any tabs. © 2001 Scripta Technica, Heat Trans Asian Res, 30(7): 561–570, 2001
Natural convection heat transfer in eccentric horizontal annuli between a heated outer tube and a cooled inner tube with different orientation: The case of an elliptical outer tube
Authors: Hirose Koichi , Hachinohe Toshitaka , Ishii Youji
Published: August 2002

This study conducts numerical analyses and experiments on natural convection heat transfer in eccentric horizontal annuli between a heated outer tube and a cooled inner tube with different orientations. The outer tube is an elliptical tube, and the inner tube is a cylindrical tube. Experiments are conducted with the outer tube oriented to the vertical side and horizontal side, respectively. The numerical analyses were performed by changing the oriented angle and eccentricity parameters. Results obtained for different conditions are presented as temperature profiles, flow patterns, local Nusselt numbers, and total heat transfer. It is found that the heat transfer enhancement effect or heat transfer obstruction effect for the total heat transfer is changed by eccentricity and oriented angle. © 2001 Scripta Technica, Heat Trans Asian Res, 30(8): 624–635, 2001
Reconstructing floodplain sedimentation rates from heavy metal profiles by inverse modelling
Authors: Middelkoop Hans
Published: August 2002

The embanked floodplains of the lower River Rhine in the Netherlands contain large amounts of heavy metals, which is a result of many years deposition of contaminated overbank sediments. Depending on local sedimentation rates and changing pollution trends in the past, the metal pollution varies greatly between different floodplain sections as well as vertically within the floodplain soil profiles. Maximum metal concentrations in floodplain soils vary from 30 to 130 mg/kg for Cu, from 70 to 490 mg/kg for Pb and from 170 to 1450 mg/kg for Zn. In the present study these metals were used as a tracer to reconstruct sedimentation rates at 28 sites on the lower River Rhine floodplains. The temporal trend in pollution of the lower River Rhine over the past 150 years was reconstructed on the basis of metal concentrations in sediments from small ponds within the floodplain area. Using a one‐dimensional sedimentation model, average sedimentation rates over the past century were determined using an inverse modelling calibration procedure. The advantage of this method is that it uses information over an entire profile, it requires only a limited number of samples, it accounts for post‐depositional redistribution of the metals, and it provides quantitative estimates of the precision of the sedimentation rates obtained. Estimated sedimentation rates vary between about 0·2 mm/year and 15 mm/year. The lowest metal concentrations are found in the distal parts of floodplain sections with low flooding frequencies and where average sedimentation rates have been less than about 5 mm/year. The largest metal accumulations occur in low‐lying floodplain sections where average sedimentation rates have been more than 10 mm/year. Copyright © 2002 John Wiley & Sons, Ltd.
Simulating overland flow following wildfire: mapping vulnerability to landscape disturbance
Authors: Beeson Peter C. , Martens Scott N. , Breshears David D.
Published: August 2002

The probability of landscape‐scale disturbances such as fire are expected to increase in the future due to anticipated climate changes and past land management practices. These disturbances can produce dramatic changes in hydrologic responses (e.g. overland flow) that can pose risks to human life, infrastructure, and the environment. Assessing these risks and associated remediation strategies requires spatially explicit evaluation of upland hydrology. However, most current evaluation methods focus on a specified location within a watershed, precluding estimation of spatially distributed, upland, hydrological response; and those that do consider spatial variability usually do not account for redistribution of overland flow among adjacent subunits. Here we highlight the use of a spatially distributed model for assessing spatial changes in upland hydrologic response following landscape‐scale disturbance. Using a distributed model called SPLASH (Simulator for Processes of Landscapes: Surface/Subsurface Hydrology), we simulated pre‐ and post‐fire scenarios based on the Cerro Grande fire (Los Alamos, NM, USA; May 2000) over 17 300 ha (resolution of 30 m × 30 m) for 2 year and 100 year design storms. For the 2 year storm, maximum overland flow rates for burned cells in the post‐fire scenario greatly exceeded those for pre‐fire conditions (modes: pre‐fire, 3·25 × 10−10 m3 s−1; post‐fire, 7·0 × 10−10 m3 s−1). For the 100 year storm, maximum overland flow was much greater than for the 2 year storm (modal pre‐fire: 31·8 × 10−10 m3 s−1), with the difference between pre‐ and post‐fire simulations being less dramatic (modal post‐fire: 48·6 × 10−10 m3 s−1). Mapped differences between pre‐ and post‐fire provide a means for prioritizing upland areas for remediation using an approach that accounts not only for topography, soils, and plant cover, but also for the redistribution of overland flow. More generally, our results highlight the potential utility of spatially distributed models to focus and prioritize rehabilitation efforts for future assessments of risk following landscape‐scale disturbance. Copyright © 2001 John Wiley & Sons, Ltd.
Time domain reflectometry measurement principles and applications
Authors: Jones Scott B. , Wraith Jon M. , Or Dani
Published: August 2002

Time domain reflectometry (TDR) is a highly accurate and automatable method for determination of porous media water content and electrical conductivity. Water content is inferred from the dielectric permittivity of the medium, whereas electrical conductivity is inferred from TDR signal attenuation. Empirical and dielectric mixing models are used to relate water content to measured dielectric permittivity. Clay and organic matter bind substantial amounts of water, such that measured bulk dielectric constant is reduced and the relationship with total water content requires individual calibration. A variety of TDR probe configurations provide users with site‐ and media‐specific options. Advances in TDR technology and in other dielectric methods offer the promise not only for less expensive and more accurate tools for electrical determination of water and solute contents, but also a host of other properties such as specific surface area, and retention properties of porous media. Copyright © 2002 John Wiley & Sons, Ltd.
Extracellular matrix building marked by the N‐terminal propeptide of procollagen type I reflect aggressiveness of recurrent breast cancer
Authors: Jensen Benny Vittrup , Johansen Julia Sidenius , Skovsgaard Torben , Brandt Jette , Teisner Børge
Published: August 2002

The purpose of our study was to examine the association between extracellular matrix homeostasis and aggressive breast cancer as reflected by the synthesis of type I collagen marked by circulating concentration of the aminoterminal propeptide of type I procollagen (PINP). Pre‐therapeutic serum PINP concentrations were measured in 154 healthy women and 100 patients referred with their first metastatic manifestation of breast cancer and correlated to the metastatic pattern, response to therapy, time to progression and survival with a minimal follow‐up of 5 years. Fifty‐four percent of the patients had serum PINP concentrations greater than the 95th percentile of the healthy controls and 38% were high PINP level patients with values clearly outside normal range (>125 ng/ml). Patients with high PINP levels were more sick (p = 0.002), had a higher tumor burden (p = 0.013) and revealed a lower responsiveness to anthracycline‐based therapy (p = 0.0002) as well as an accelerated time to disease progression (p = 0.00001) and death (p = 0.0006). Median survival in the high serum PINP level group was less than half of that in the group with low PINP level (14.5 vs. 32 months). The lowest PINP levels were seen when the cancer was restricted to the lymph node and skin and increasing PINP levels were found if the cancer had spread to the lungs, the bones, the bone marrow and the liver. High PINP level at recurrence and lack of estrogen receptors (ER) independently reflected aggressive tumor behavior after recurrence with an equal great impact on time to progression and survival. Patients with a high PINP level and primarily ER‐negative tumors survived a median of only 6 months with no one alive after 22 months. By contrast patients with a low PINP level and ER‐positive tumors had a median survival of 37 months and 23% were still alive after 5 years. Aggressive breast cancer induces a strong fibroproliferative response with synthesis of type I collagen. Serum PINP levels may be a diagnostic and prognostic tool that indicate breast cancer activity, aggressiveness, expansion and metastasis and a predictor of outcome after anthracycline‐based chemotherapy. © 2002 Wiley‐Liss, Inc.
Chromosome 6p21.2, 18q21.2 and human papilloma virus (HPV) DNA can predict prognosis of cervical cancer after radiotherapy
Authors: Harima Yoko , Sawada Satoshi , Nagata Kenji , Sougawa Mitsuharu , Ohnishi Takeo
Published: August 2002

Loss of heterozygosity (LOH) is one of the most important mechanisms for inactivation of tumor‐suppressor genes. Studies of LOH in patients with cervical carcinoma have reported a high frequency of LOH on 3p21.3, 6p21.2, 17p13.1, and 18q21.2. Our study explored whetherp53status, human papilloma virus (HPV), and LOH on chromosome 3p21.3, 6p21.2, 17p13.1, and 18q21.2 are associated with treatment outcome in 65 patients with cervical cancer after radiotherapy. Tumors and normal DNA were analyzed by polymerase chain reaction (PCR) for genetic losses at 10 polymorphic microsatellite loci. The presence of HPV and its type were analyzed by PCR‐based assay using the consensus primers for E6, E7, and L1 region. Mutations of thep53gene were identified by a single‐strand conformation polymorphism analysis. Chromosomes 3p21.3, 6p21.2, 17p13.1, and 18q21.2 were involved in the LOH in 23.1%, 41.5%%, 33.8%, and 23.1% of the tumors in our study, respectively. HPV‐positive tumors were found in 73.8% of the patients andp53mutation in 10.8%. The patients with LOH on chromosome 6p21.2 and 18q21.2 survived significantly shorter compared with those without LOH on chromosome 6p21.2 and 18q21.2 in both the overall survival (P= 0.006 andP= 0.007) and the disease‐free survival (P= 0.005 andP= 0.008). The HPV‐negative patients survived significantly shorter compared with the HPV‐positive patients in both the overall survival (P= 0.01) and the disease‐free survival (P= 0.04). According to multivariate analysis, HPV status (P= 0.0004,P= 0.01), LOH on 6p21.2 (P= 0.006,P= 0.02), and LOH on 18q21.2 (in bothP= 0.01) is a significant predictor of both overall and disease‐free survival time. The results of our study suggest that absence of HPV infection, LOH on 6p21.2, and LOH on 18q21.2 are the most important determinants of outcome of patients with cervical carcinoma after radiotherapy. © 2001 Wiley‐Liss, Inc.
Retroviral gene transfer of interferon‐inducible protein 10 inhibits growth of human melanoma xenografts
Authors: Feldman Andrew L. , Friedl Josef , Lans Titia E. , Libutti Steven K. , Lorang Dominique , Miller Marshall S. , Turner Ewa M. , Hewitt Stephen M. , Alexander H. Richard
Published: August 2002

Interferon‐inducible protein 10 (IP‐10) is an immunomodulatory chemokine recently recognized to have potent antiangiogenic activity in vivo. Due to difficulties in the stability, manufacture and chronic administration of recombinant forms of endogenous antiangiogenic proteins, antiangiogenic gene therapy has emerged as a promising new form of cancer treatment. We retrovirally transduced A375 human melanoma cells with the human IP‐10 gene and injected cells subcutaneously into nude mice. IP‐10‐transduced cells also were mixed with null‐transduced cells in varying proportions before injection. In vivo growth of IP‐10‐transduced melanoma cells was markedly diminished compared to parental or null‐transduced cells (p = 0.0002, Kruskal‐Wallis test). This growth inhibition was associated with a marked reduction in microvessel density. The degree of growth inhibition of tumors following injection of a mixed population of null‐ and IP‐10‐transduced cells was directly associated with the fraction of IP‐10‐transduced cells present. We conclude that retroviral transduction of human melanoma cells with the IP‐10 gene leads to sufficient protein secretion to inhibit angiogenesis and tumor growth. These findings suggest that IP‐10 gene therapy might be an effective therapy in patients with cancer. Published 2002 Wiley‐Liss, Inc.
Loss of heterozygosity analysis at the BRCA loci in tumor samples from patients with familial breast cancer
Authors: Osorio Ana , de la Hoya Miguel , Rodríguez‐López Raquel , Martínez‐Ramírez Angel , Cazorla Alicia , Granizo Juan José , Esteller Manel , Rivas Carmen , Caldés Trinidad , Benítez Javier
Published: August 2002

The BRCA1 and BRCA2 genes are responsible for a high proportion of familial breast cancer; germline mutations in these genes confer a lifetime risk of about 70% for developing breast cancer. Most of the described deleterious mutations are small deletions or insertions that originate a truncated protein; however, in many cases, they are amino acid changes whose significance is unknown. In these cases, there are some tests that can analyze the meaning of these variants, but most remain unclassified. The BRCA genes are tumor supressors and it is beleived that complete loss of the wild‐type allele is a common mechanism of inactivation in tumors from patients carrying a germline deleterious mutation in these genes; if this is true, loss of heterozygosity (LOH) analysis in the tumor sample could help to distinguish if a rare variant is either a deleterious mutation or a common polymorphism. In the present study, we performed LOH analysis at the BRCA loci in 47 tumors from patients who belonged to high‐risk breast cancer families and were carriers of any type of alteration in these genes. Our results suggest that (i) loss of the wild‐type allele is the most common mechanism of inactivation in tumors from patients who carry a deleterious mutation in any of the genes, (ii) this loss is not common when we analyze familial tumors not associated with mutations in BRCA and (iii) LOH can be used to clarify variants of unknown significance in the BRCA genes. © 2002 Wiley‐Liss, Inc.
Dosimetric and radiographic correlates to prostate brachytherapy‐related rectal complications
Authors: Han Ben H. , Wallner Kent E.
Published: August 2002

Despite rates of radiation proctitis reported in the 1% to 9% range in most series, there is little information regarding rectal morbidity and dosimetric parameters. Accordingly, we have analyzed computed tomography (CT)‐based dosimetric parameters based on a series of patients with endoscopically proven radiation proctitis. Nine patients diagnosed with radiation proctitis on endoscopy were identified in a prior review of 160 consecutively treated patients at the University of Washington in 1997. For each proctitis patient, two patients with no rectal bleeding matched for prostate size, isotope, and dose were selected as controls. Axial CT images obtained 2 to 4 hour postoperatively were used for postimplant dosimetry. Dose volume histograms of the rectum, surface area of the outer rectal wall receiving ≥ 100% of the prescribed dose, maximum rectal dose, and length of rectum receiving ≥ 100% prescription were obtained. Preimplant CT scans were used to group patients into three categories based on the amount of apparent rectal contact with the prostate. All rectal dosimetric parameters were statistically different between patients with or without rectal bleeding. The mean surface area receiving at least 100% prescription dose was 3.1 cm2 for the controls vs. 6.9 cm2 for the rectal bleeders (P = 0.001). The volume of rectum receiving at least 100% of prescription dose was 0.6 cc for the controls vs. 2.5 cc for the bleeders (P = 0.00008). Patients with full prostate‐rectal contact had significantly higher rectal dose parameters compared to those with partial or no rectal contact. All nine proctitis patients were in the full‐rectal‐contact group compared to only seven of 18 (39%) controls. This detailed dosimetric analysis shows higher rectal doses for patients with radiation proctitis, making it a potential method of identifying patients at higher risk for receiving excessive rectal doses based on the anatomic relationship between the rectum and prostate on CT scan. Published 2001 Wiley‐Liss, Inc.
Stromelysin‐3 expression by mammary tumor‐associated fibroblasts under in vitro breast cancer cell induction
Authors: Wang Chang Shu , Têtu Bernard
Published: August 2002

To understand better the influence of the host stromal phenotype on stromal expression of stromelysin‐3 (ST3) in breast cancer, we have investigated ST3 expression by host stromal cells isolated from 9 different primary breast carcinomas. These tumor‐associated fibroblasts were cocultivated with 3 epithelial cancer cell lines of mammary origin (MDA‐MB‐231, SK‐BR‐3 and MCF‐7), as well as with normal human mammary epithelial cells (NME and 184A1) and keratinocytes, using both direct and indirect coculture systems. ST3 expression was demonstrated by both in situ hybridization and immunocytochemistry. The results showed that ST3 expression by stromal cells was cancer‐specific. Indeed, ST3 expression by tumor‐associated stromal cells was induced by 3 malignant cancer cell lines (MDA‐MB‐231, SK‐BR‐3 and MCF‐7), whereas no ST3 was expressed under normal mammary epithelial cell stimulation. ST3 expression was weak or absent in unstimulated tumor‐associated fibroblasts. However, after direct coculture with cancer cells, expression of ST3 transcripts reappeared in 8 of the 9 cases and was observed only in fibroblasts located in close contact with tumor cells. Under similar coculture conditions and using the same cancer cell line stimulation, ST3 expression was, however, quite variable among these 9 cases, reflecting the difference of protease expression observed on the sections of the original tumors. Tumor induction of ST3 expression was much more important by direct cell‐cell contact than by indirect stimulation and was not influenced by the addition of basic fibroblast growth factor (bFGF) and anti‐bFGF to the culture medium. Our results suggest that the host stromal cell phenotype may significantly influence host stromal cell protease expression under cancer cell stimulation. © 2002 Wiley‐Liss, Inc.
Market structure and the persistence of sectoral real exchange rates
Authors: Cheung Yin‐Wong , Chinn Menzie , Fujii Eiji
Published: August 2002

We examine the relationship between market structure and the persistence of US dollar‐based sectoral real exchange rates for 14 OECD countries. Our empirical results based on disaggregated data suggest that differences in market structure significantly determine the rates at which deviations from sectoral purchasing power parity decay. Specifically, industries with a larger price‐cost margin are found to exhibit slower parity reversion of their sectoral real exchange rates. Further, as the degree of intra‐industry trade activity increases, sectoral real exchange rate persistence becomes more pronounced. These findings suggest that an imperfectly competitive market structure contributes to the well‐documented persistence in real exchange rates. Copyright © 2001 John Wiley & Sons, Ltd.
Stress, maternal depression, and negative mother–infant interactions in relation to infant attachment
Authors: Coyl Diana D. , Roggman Lori A. , Newland Lisa A.
Published: August 2002

This research examined factors contributing to infant attachment security such as stressful events, maternal depression, negative parent–infant interactions, and spanking. The sample included 169 mostly European American mothers and infants who were qualified applicants to Early Head Start. Interview and self‐report measures of contextual stress, mothers' depressive symptoms, mother–infant negative interactions, and discipline strategies were administered by trained researchers when infants were 14 months old. In addition, mothers' completed the Attachment Q‐set (AQS, version 3.0, Waters, 1987). Infant security was lower when maternal depression was higher, when mothers were more dissatisfied in their interactions with infants, and when these infants were spanked more frequently. A path model was constructed to examine the direct and indirect paths from predictor variables to infant attachment security. Maternal depression, negative interactions, and spanking directly affected infant attachment security. Economic stress and relationship stress directly affected maternal depression and frequency of spanking, thereby indirectly influencing infant attachment security. These findings suggest that understanding the influences on infant attachment security is essential for effective early prevention and intervention that promote optimal development. ©2002 Michigan Association for Infant Mental Health.
Sequential testing of duration data: the case of the Pennsylvania ‘reemployment bonus’ experiment
Authors: Bilias Yannis
Published: August 2002

Cost considerations and the need to report the results promptly make it desirable to examine data as it accumulates and to terminate an experimental study as soon as definite statistical conclusions can be drawn. These ideas are illustrated in a retrospective analysis of the Pennsylvania ‘Reemployment Bonus’ experiment. Recently developed large‐sample theory for a variety of sequentially computed score processes of time‐to‐event (duration) data with staggered entry enables one to construct stopping boundaries of a prescribed level of significance. The gains from the use of sequential methodology appear to be worth while. Copyright © 2000 John Wiley & Sons, Ltd.
Measuring predictability: theory and macroeconomic applications
Authors: Diebold Francis X. , Kilian Lutz
Published: August 2002

We propose a measure of predictability based on the ratio of the expected loss of a short‐run forecast to the expected loss of a long‐run forecast. This predictability measure can be tailored to the forecast horizons of interest, and it allows for general loss functions, univariate or multivariate information sets, and covariance stationary or difference stationary processes. We propose a simple estimator, and we suggest resampling methods for inference. We then provide several macroeconomic applications. First, we illustrate the implementation of predictability measures based on fitted parametric models for several US macroeconomic time series. Second, we analyze the internal propagation mechanism of a standard dynamic macroeconomic model by comparing the predictability of model inputs and model outputs. Third, we use predictability as a metric for assessing the similarity of data simulated from the model and actual data. Finally, we outline several non‐parametric extensions of our approach. Copyright © 2001 John Wiley & Sons, Ltd.
Stochastic frontier models with random coefficients
Authors: Tsionas Efthymios G.
Published: August 2002

The paper proposes a stochastic frontier model with random coefficients to separate technical inefficiency from technological differences across firms, and free the frontier model from the restrictive assumption that all firms must share exactly the same technological possibilities. Inference procedures for the new model are developed based on Bayesian techniques, and computations are performed using Gibbs sampling with data augmentation to allow finite‐sample inference for underlying parameters and latent efficiencies. An empirical example illustrates the procedure. Copyright © 2002 John Wiley & Sons, Ltd.
Genetic toxicology studies with glutaraldehyde
Authors: Vergnes Jane S. , Ballantyne Bryan
Published: August 2002

Glutaraldehyde (GA; CAS no. 111‐30‐8) has a wide spectrum of industrial, scientific and biomedical applications, with a potential for human exposure particularly in its biocidal applications. The likelihood for genotoxic effects was investigatedin vitroandin vivo. ASalmonella typhimuriumreverse mutation assay showed no evidence for mutagenic activity with strains TA98, TA1535, TA1537 and TA1538, with or without metabolic activation. However, there was a weak mutagenic response (1.9–2.3‐fold at the highest non‐toxic concentration) with TA100 in the presence of metabolic activation. In a Chinese hamster ovary (CHO) forward gene mutation assay (HGPRT locus) there were no consistent, statistically significant, reproducible or dosage‐related increases in the frequency of 6‐thioguanine resistant cells. There were no reproducible or dosage‐related increases in sister chromatid exchanges in anin vitrotest in CHO cells. Anin vitrocytogenetics study in CHO cells showed no evidence for an increase in chromosomal aberrations on treatment with GA, either in the presence or absence of metabolic activation.In vivo, a mouse peripheral blood micronucleus test showed no increase in micronucleated polychromatophils at sampling times of 30, 48 and 72 h after acute gavage dosing with GA at 40, 80 and 125 mg kg−1(corresponding to 25, 50 and 85% of theLD50). The absence of anin vivoclastogenic potential was confirmed by no increase in chromosomal aberrations in a rat bone marrow cytogenetics study with sampling at 12, 24 and 48 h after acute gavage dosing with GA (12.5, 30 or 60 mg kg−1with males, and 7.5, 20 or 40 mg kg−1with females). Thus, in this series of tests, GA produced genotoxic effectsin vitroonly in a bacterial reverse mutation assay with no evidence forin vivogenotoxicity. Copyright © 2002 John Wiley & Sons, Ltd.
Feasibility study using a natural compound (reuterin) produced by Lactobacillus reuteri in sterilizing and crosslinking biological tissues
Authors: Chen Chiun‐Nan , Sung Hsing‐Wen , Liang Hsiang‐Fa , Chang Wen‐Hsiang
Published: August 2002

Bioprostheses derived from biological tissues have to be fixed and subsequently sterilized before they can be implanted in humans. Currently available crosslinking agents and sterilants used in the fixation or sterilization of biological tissues such as glutaraldehyde and formaldehyde are all highly cytotoxic, which may impair the biocompatibility of bioprostheses. Therefore, it is desirable to provide an agent suitable for use in biomedical applications that is of low cytotoxicity and may form sterile and biocompatible crosslinked products. To achieve this goal, a natural compound (reuterin), produced by Lactobacillus reuteri in the presence of glycerol, was used by our group. It is known that reuterin has antibacterial, antimycotic, and antiprotozoal activities. Additionally, as in the case with formaldehyde, reuterin may react with the free amino groups in biological tissues by using its aldehyde functional group. Therefore, it was speculated that reuterin could be used as a crosslinking agent and a sterilant for biological tissues in the same way as glutaraldehyde and formaldehyde. In the study, the production of reuterin, produced by Lactobacillus reuteri under control conditions, was reported. Preparative chromatography was used to purify reuterin. Also, the minimal inhibitory concentration and minimal bactericidal concentration of reuterin and its antimicrobial activity on a contaminated tissue were investigated. In addition, the cytotoxicity of reuterin was evaluated. Glutaraldehyde, the most commonly used sterilant in the sterilization of biological tissues, was employed as a control. Furthermore, the feasibility of using reuterin as a crosslinking agent in fixing biological tissues was studied. Fresh and the glutaraldehyde‐fixed tissues were used as controls. The results obtained in the minimal inhibitory concentration and minimal bactericidal concentration studies and in the sterilization study of a contaminated tissue indicated that the antimicrobial activity of reuterin is significantly superior to its glutaraldehyde counterpart. In addition, the results obtained in the 3‐(4,5‐dimethylthiazol‐yl)‐2,5‐diphenyltetrazolium bromide assay showed that reuterin is significantly less cytotoxic than glutaraldehyde. Additionally, it was found that reuterin is an effective crosslinking agent for biological tissue fixation. The reuterin‐fixed tissue had comparable free amino group content, denaturation temperature, and resistance against enzymatic degradation as the glutaraldehyde‐fixed tissue. In conclusion, the results obtained in this study indicate that reuterin is an effective agent in the sterilization and fixation of biological tissues. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 360–369, 2002
The use of liposomal enrofloxacin for intracellular infections in Kangal dogs and visualization of phagocytosis of liposomes
Authors: Deĝim Zelihagül , Deĝim Tuncer , Bas Levent , Elmas Muammer
Published: August 2002

It is difficult to treat intracellular infections because of the intrinsic resistance of the microorganism to most antibiotics. Moreover, these microorganisms can survive in phagocytic cells (macrophages and neutrophils). In this study, our aims were to encapsulate an antibiotic in liposomes, which will be phagocytized as well as the microorganisms in the phagocytic cell (because liposomes were prepared using lipids which have an antigenic activity and they can be phagocytized, thus, the active substance can be transferred into the cell), and to visualise with microscopy the phagocytic activity of macrophages and neutrophils to liposomes. MLV (multilamellar vesicles) fluorescein‐labeled liposomes were prepared and incubated with isolated Kangal shepherd dog macrophages and neutrophils. The phagocytosis of liposomes by monocytes was visualized step by step under the microscope. Liposomes were also observed phagocytized after incubation with neutrophils. Enrofloxacin was chosen as a model drug. Neutrophils and macrophages were isolated from Kangal shepherd dogs and infected withStaphylococcus aureus,and their phagocytic activities (PA) and microbicidal activities (MA) were determined. PA and MA values were redetermined and compared when enrofloxacin formulations were used. Liposomal enrofloxacin was found to be more effective. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 246–251, 2002
Long‐term effects of four extraction media on the fluoride release from four polyacid‐modified composite resins (compomers) and one resin‐modified glass‐ionomer cement
Authors: Behrend B. , Geurtsen W.
Published: August 2002

It was the aim of the present experiments to evaluate the fluoride leaching of four compomers and one resin‐modified glass‐ionomer cement (gic) into aqueous media over a 1‐year period. Various extraction/equilibrium solutions were applied to simulate important intraoral parameters. Specimens of Dyract™, Compoglass™ F, F2000™, one experimental compomer, and the resin‐modified gic Fuji II LC™ were stored for 366 days in distilled water (I), acidic medium (pH 4.2) (II), neutral medium (pH 7.0) (III), or solution III supplemented with 1.6 u/mL porcine liver esterase (IV). Equilibrium media were changed and fluoride concentration was measured every 48 h (first 30 d), thereafter each week (twice), then every 14 d (three times), and finally every 28 d up to a total period of 1 year. Data were statistically analyzed for significant differences by means of Scheffe′ tests (p < 0.05). The gic and the compomers leached significantly more fluoride into the acidic solution in the initial phase compared to the other media (p < 0.05). Cumulative fluoride release from all materials (except experimental compomer) was elevated because of esterase activity (p <0.05). Measurable but low quantities of fluoride were segregated into all media during the 1‐year period. But no significantly different long‐term fluoride release into the various media from the investigated materials was found. The data indicate that plaque‐associated organic acids or salivary hydrolases may increase initial fluoride release from resin‐modified gics or compomers in the oral cavity. Because long‐term fluoride release from all materials decreased to low concentrations within a 30‐day period, their caries preventive effect remains questionable. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 631–637, 2001
Pore diameter of more than 100 μm is not requisite for bone ingrowth in rabbits
Authors: Itälä Ari I. , Ylänen Heimo O. , Ekholm Clifford , Karlsson Kaj H. , Aro Hannu T.
Published: August 2002

The optimal pore size for bone ingrowth is claimed to be 100–400 μm. With the use of a highly standardized experimental model, the present study reevaluated whether a pore size of 100 μm is the threshold value for bone ingrowth into porous structures under non‐load‐bearing conditions. Titanium triangle‐shaped plates 250 or 500 μm thick were perforated with the use of a laser in order to create standard‐sized holes (∅︁ 50, 75, 100, and 125 μm) in multiple rows. The amount of bone ingrowth through the implant holes was studied in the cancellous bone of the distal rabbit femur. Twelve weeks after implantation, detailed analysis of bone ingrowth was performed with computerized image analysis of backscattered electron imaging techniques of scanning electron microscopy. The results showed that the amount of ingrown new bone was independent of the pore size and implant thickness. The median value for bone ingrowth varied between 64 and 78%. A striking feature was the formation of secondary osteonal structures even in the smallest holes. Based on these results, there is no threshold value for new bone ingrowth in pore sizes ranging from 50 to 125 μm under non‐load‐bearing conditions. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 679–683, 2001
Localization of metallic ions with gingival fibroblast subcellular fractions
Authors: Messer Regina L. W. , Lucas L. C.
Published: August 2002

Nickel‐based alloys have been in use since the 1930s; however, there are concerns regarding the release of metal ions (Be+2, Cr+6, Cr+3, Ni+2, Mo+6) from these alloys into surrounding tissues. Therefore, the objective of this study was to determine the cellular location and accumulation of ions using atomic absorption spectroscopy and correlate location with the cytotoxic, morphologic, and ultrastructural evaluations reported previously. Human gingival fibroblasts were exposed to the metal ions for 72 h. Controlled atomic absorption spectroscopy studies were used to determine the intracellular location of these ions reported as parts per million metal ions per milligram protein. Enzymatic markers were shown to correspond to the appropriate fraction indicating success in fractionation of the gingival fibroblasts. These results correspond with the cytotoxic, morphologic, and ultrastructural alterations reported previously for fibroblasts exposed to these ions. The highest concentration of beryllium ions occurred in the low‐density molecule fraction, where lipofuscin granules were found, which has been shown to contain metal ions. The highest concentrations of hexavalent chromium ions occurred in the plasma membrane and nuclear fractions followed by the mitochondria fraction, which is supported by the ions’ ability to oxidize to trivalent chromium accumulating at the membrane as well as the alterations in nuclear and mitochondrial function. For trivalent chromium, the highest concentrations occurred in the low‐density molecule and the plasma membrane fractions, which correlates with the ions’ inability to readily cross membranes. The highest concentration of molybdenum ions occurred in the plasma membrane fraction correlating with alterations in membrane morphology and increased numbers of myelin figures. The highest concentration of nickel ions was associated with the cytosol fraction where lipid droplets seen in the transmission electron micrographs were located. The current study demonstrates that a successful subcellular fractionation was obtained on gingival fibroblasts and that the location of metallic ions within the fractions correlated with cellular alterations reported previously. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 466–472, 2002
Dynamic changes in cytokine levels in serum and synovial fluid following filtration leukocytapheresis therapy in patients with rheumatoid arthritis
Authors: Hidaka Toshihiko , Suzuki Kimihiro , Kawakami Makoto , Okada Makoto , Kataharada Kouji , Shinohara Tadashi , Takamizawa‐Matsumoto Mitsuyo , Ohsuzu Fumitaka
Published: August 2002

We attempted to determine whether various cytokine levels in the serum and synovial fluid (SF) of rheumatoid arthritis (RA) patients are influenced by the performance of filtration leukocytapheresis (LCP). The filtration LCP procedure that used a Cellsorba® column (LCP group: n=22; responder subgroup: n=17, non‐responder subgroup: n=5) or sham apheresis (control group; n=7) was repeated three times at 1‐week intervals. Serum (LCP group, n=22; control group, n=7) and SF (LCP group, n=6; control group, n=3) samples were collected before and after LCP. Levels of tumor necrosis factor α (TNFα), interleukins (IL‐1β, IL–2, IL‐6, IL‐8, IL‐10, and IL‐15), granulocyte–macrophage colony–stimulating factor (GM‐CSF), monocyte chemoattractant protein–1 (MCP‐1), RANTES were measured by an enzyme‐linked immunosorbent assay. Serum TNFα, IL‐15, and RANTES were significantly reduced only in the LCP group. Serum IL‐10 significantly increased only in the LCP group. In the LCP subgroup, serum IL‐15, GM‐CSF, and RANTES levels were reduced significantly, while serum IL‐10 levels increased significantly only in the responder group after treatment. Serum TNFα levels were reduced significantly in both subgroups. Changes in serum IL‐10 correlated positively with the improvement of patient's assessment of pain and global severity, and physician's assessment of global severity. These results indicate that the removal of leukocytes from the peripheral blood of RA patients provokes dynamic changes in some cytokine levels in the serum and/or synovial fluid. These changes may explain some of the mechanisms by which the articular symptoms are improved by filtration LCP. J. Clin. Apheresis. 16:74–81, 2001. © 2001 Wiley‐Liss, Inc.