bluuebunny/crossref_metadata_2025 huggingface dataset:
A retrospective analysis of two independent prospective cartilage repair studies: autogenous perichondrial grafting versus subchondral drilling 10 years post‐surgery
Authors: Bouwmeester Phianne S. J. M. , Kuijer Roel , Homminga George N. , Bulstra Sjoerd K. , Geesink Rudolph G. T.
Published: October 2002

Background: Experimental data indicate that perichondrial grafting to restore articular cartilage defects will result in repair with hyaline‐like cartilage. In contrast, debridement and drilling results in repair with fibro‐cartilage. In this retrospective study the longterm clinical results of both procedures were compared to evaluate the theoretical benefit of repair with hyaline‐like tissue.

Methods: From two independent studies patients were selected with a cartilage defect in their knee. The selection was performed using strict inclusion criteria published elsewhere [Bouwmeester et al. Int. Orthop. 21 (1997) 313]. The patients were treated with either a perichondrium transplantation (PT group, n = 14) or with an ‘open’ debridement and drilling procedure (DD group, n = 11). The results of both procedures after 10–11 years were evaluated using the Hospital for Special Surgery Knee Score (HSSS), X‐ray examination, clinical examination and visual analogue scales (VAS) for pain during walking and at rest.

Results: Both procedures resulted in a general improvement compared to the situation before the operation. After an average of 10 years in the PT group there were three failures, in the DD group none, success rates were 78% and 100%, respectively. When comparing the successful PT patients with the DD patients, there were no differences in HSSS and VAS data. Both groups showed an equal number of irregular operation surface sites on X‐ray (PT 9/11 versus DD 8/10).

Conclusions: This study shows that clinically at 10 years follow‐up no difference was observed between debridement and drilling and perichondrium transplantation for treatment of an isolated cartilage defect. This raises questions about ongoing research to develop methods in order to improve the results of debridement and drilling as therapy for an isolated cartilage defect in a young patient (⩽ 40 years). © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Spinal degenerative disk disease (DDD) in female macaque monkeys: epidemiology and comparison with women
Authors: Kramer Patricia Ann , Newell‐Morris Laura L. , Simkin Peter A.
Published: October 2002

Spinal degenerative disk disease (DDD) in a radiographic, cross‐sectional sample of 192 female macaque monkeys, approximately 5–30 years old, is described. The presence and extent of disk space narrowing (DSN) and anterior osteophytosis were assessed with reference to age, average lifetime body mass, and distribution within the thoracolumbar spine. Age was a strong correlate of disk narrowing and osteophytosis, with early signs appearing at equivalent ages in both species and increasing in prevalence thereafter. Macaques showed a far greater prevalence of DDD, especially in the oldest age group, than has been reported in the human data. Body mass was associated with disk narrowing in the macaque, but not with osteophytosis. The two species differed little in the pattern of distribution of DDD along the spine. Our results suggest that bipedality is not the singular, or even the most important, biomechanical factor in the development of human DDD. Rather, others shared postural regimes, e.g., sitting, may be responsible for the onset and progression of DDD in both species. The macaque model could substantially add to the under‐standing and, potentially, treatment of this oftentimes debilitating condition. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Human knee and ankle cartilage explants: Catabolic differences
Authors: Eger Wolfgang , Schumacher Barbara L. , Mollenhauer Jürgen , Kuettner Klaus E. , Cole Ada A.
Published: October 2002

The prevalence of osteoarthritis (OA) is lower in some joints, i.e., the ankle, than in the knee. We have compared the cartilages from these two joints of the same limb in adult donors (matched pairs). Our data to date suggest that there are metabolic, biochemical and biomechanical differences between the cartilages of the two joints. The current study has focused on extending the metabolic studies comparing the response of chondrocytes to Interleukin‐1β (IL‐1β) and osteogenic protein 1 (OP‐1) by analyzing changes in sulfate incorporation into glycosaminoglycans (GAGs) as a measure of proteoglycan (PG) synthesis. Human adult chondrocytes from normal knees (tibiofemoral) and ankles (talocrural) joints cultured as explants both responded to IL‐1β after 72 h by decreasing PG synthesis; however, the IC50 for the knee chondrocytes was 6.2 pg/ml, while that for the ankle was 35 pg/ml. When the explants were incubated for 72 h with IL‐1β and allowed to rebound without IL‐1β, synthesis of PG was significantly elevated by ankle chondrocytes within five days; knee chondrocytes were unable to significantly increase synthesis even after eight days. However, in both knee and ankle, application of OP‐1 enhanced PG synthesis in the rebound phase. In response to IL‐1, an upregulation of proteinase activity was detectable by an increase in the neoepitopes proteolytically‐generated by both aggrecanase and matrix metalloproteinases (MMPs), in the deep zone of the knee cartilage. Stromelysin and collagenase were upregulated as well. The data emerging from these studies confirm that the ankle is less responsive to catabolic stimulation and more responsive to anabolic stimulation following IL‐1 removal. These differences in metabolic activity between the cartilages of the two joints could in part help to explain their differences in susceptibility to OA. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
ACL transection influences mRNA levels for collagen type I and TNF‐α in MCL scar
Authors: Majima Tokifumi , Lo Ian K. Y. , Randle John A. , Marchuk Linda L. , Shrive Nigel G. , Frank Cyril B. , Hart David A.
Published: October 2002

To assess the mRNA expression of extracellular matrix genes which might correlate with or contribute to mechanically weaker medial collateral ligament (MCL) scars in the ACL‐deficient rabbit knee joint compared to those in anterior cruciate ligament (ACL) intact knee joints, a bilateral MCL injury was induced in 10 skeletally mature female NZW rabbits. As part of the same surgical procedure, the ACL was transected in one of the knees while the contralateral knee had a sham procedure. The side having the combined MCL and ACL injury was randomly assigned. After six weeks, the rabbits were euthanized. Histological assessments were performed on samples of the MCL scars from each operated knee (n = 3 animals) and mRNA levels for collagen type I, III, V, decorin, biglycan, lumican, fibromodulin, TGF‐β, IL‐1, TNF‐α, MMP‐1, MMP‐1, MMP‐13, and a housekeeping gene (GAPDH) were assessed using semiquantitative RT‐PCR on RNA isolated from the MCL scar tissue of the remaining animals (n = 7 animals). Levels of mRNA for each gene were normalized using the corresponding GAPDH value. Results showed that the total RNA yield (per mg wet weight) in the MCL scar of the ACL‐deficient knee was significantly greater than that in the MCL scar from the ACL‐intact knee. Collagen type I mRNA levels were significantly lower and mRNA levels for TNF‐α were significantly greater in the scars of ACL‐deficient knees compared to scars from ACL‐intact joints. There were no significant differences between ACL‐deficient and ACL‐intact knees with respect to MCL scar mRNA levels for the remaining genes assessed. Histologically, the “flaw” area, which has been shown to correlate with mechanical properties in previous studies, was significantly greater in MCL scars from ACL‐deficient knees than in the ACL‐intact MCL scars. The mean number of cells/mm2 in MCL scars from ACL‐deficient knees was significantly greater than in MCL scars from ACL‐intact knees. The present study suggests that MCL scar cell metabolism is differentially influenced by the combined injury environment. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Measurement of anterior–posterior knee laxity: a comparison of three techniques
Authors: Fleming Braden C. , Brattbakk Bjarne , Peura Glenn D. , Badger Gary J. , Beynnon Bruce D.
Published: October 2002

Several non‐invasive techniques have been developed to assess anterior–posterior (A–P) laxity of the knee, however, their accuracy remains unclear. Roentgen Stereophotogrammetry Analysis (RSA) is a three‐dimensional motion analysis method that has been shown to be an accurate tool for evaluating joint kinematics. Thus, RSA provides a means that can be used to evaluate other less invasive techniques. The objectives of this study were to compare A–P laxity values as measured using the KT‐1000 Knee Arthrometer, planar stress radiography and RSA, and to determine if they detect similar changes in A–P laxity over time in 15 subjects following anterior cruciate ligament reconstruction with patellar tendon autografts. The A–P laxity values of the injured knee were measured immediately following surgery and at their 3‐, 6‐, and 12‐month follow‐up visits. A–P laxity was defined as the A–P translation of the tibia relative to the femur that occurred between the posterior and anterior shear load limits of −90 to +130 N, respectively. The values of A–P laxity across all time points were 11.4 ± 3.0, 10.2 ± 3.3, and 6.9 ± 3.0 mm (mean ± standard deviation) for the KT‐1000, planar stress radiography and the RSA methods, respectively. These values were significantly different from each other (p < 0.001). The two‐dimensional analyses techniques (planar stress radiography and the KT‐1000) consistently over‐estimated the true laxity values that were obtained using the three‐dimensional RSA technique. Significant increases in A–P laxity values over time were also detected with the KT‐1000 (p = 0.04) and the RSA technique (p = 0.04). However, this increase was not evident when using planar stress radiography (p = 0.89). This study determined that the KT‐1000 and RSA document temporal changes in A–P laxity following ACL reconstruction that were not documented by planar stress radiography. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Preliminary report on the biocompatibility of a moldable, resorbable, composite bone graft consisting of calcium phosphate cement and poly(lactide‐co‐glycolide) microspheres
Authors: Simon Carl G. , Khatri Chetan A. , Wight Scott A. , Wang Francis W.
Published: October 2002

We have assessed the biocompatibility of a new composite bone graft consisting of calcium phosphate cement (CPC) and poly(lactide‐co‐glycolide) (PLGA) microspheres (approximate diameter of 0.18–0.36 mm) using cell culture techniques. CPC powder is mixed with PLGA microspheres and water to yield a workable paste that could be sculpted to fit the contours of a wound. The cement then hardens into a matrix of hydroxyapatite microcrystals containing PLGA microspheres. The rationale for this design is that the microspheres will initially stabilize the graft but can then degrade to leave behind macropores for colonization by osteoblasts. The CPC matrix could then be resorbed and replaced with new bone. In the present study, osteoblast‐like cells (MC3T3‐E1 cells) were seeded onto graft specimens and evaluated with fluorescence microscopy, environmental scanning electron microscopy and the Wst‐1 assay (an enzymatic assay for mitochondrial dehydrogenase activity). Cells were able to adhere, attain a normal morphology, proliferate and remain viable when cultured on the new composite graft (CPC–PLGA) or on a control graft (CPC alone). These results suggest that our new cement consisting of CPC and PLGA microspheres is biocompatible. This is the first time that a ‘polymer‐in‐mineral’ (PLGA microspheres dispersed in a CPC matrix) cement has been formulated that is moldable, resorbable and that can form macropores after the cement has set. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Immunohistological analysis of transglutaminase factor XIIIA expression in mouse embryonic growth plate
Authors: Nurminskaya M. V. , Linsenmayer T. F.
Published: October 2002

Previously we demonstrated the expression of Factor XIIIA (FXIIIA), a coagulation transglutaminase, in avian embryonic growth plate. To explore whether FXIIIA is also expressed by chondrocytes of the mammalian cartilage anlagen of bones, we analyzed the mouse embryonic growth plate by immunostaining using anti‐FXIIIA antibodies developed against human and chicken proteins. We revealed the expression of FXIIIA in the epiphyseal growth plate, where FXIIIA appears first intracellularly in the zone of proliferation/maturation, and remains intra‐ and extracellularly throughout the hypertrophic zone. Externalization of FXIIIA occurs before mineralization. Transglutaminase activity was assayed in organ cultures using rhodamine‐labeled synthetic substrate Pro–Val–Lys–Gly. Enzymatic activity shows a restricted distribution in cartilage and correlates with FXIIIA expression pattern, suggesting that cartilagenous transglutaminase activity is due, at least partially, to the FXIIIA isoform. We conclude, that coagulation factor FXIIIA is expressed by chondrocytes of embryonic mouse long bone cartilages in a strictly regulated pattern, which correlates with chondrocyte differentiation and matrix mineralization. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Effects of shear stress on nitric oxide and matrix protein gene expression in human osteoarthritic chondrocytes in vitro
Authors: Lee Mel S. , Trindade Michael C. D. , Ikenoue Takashi , Schurman David J. , Goodman Stuart B. , Smith R. Lane
Published: October 2002

Mechanical loading alters articular cartilage metabolism. However, mechanisms underlying intracellular signaling and communication between cells in response to mechanical stresses remain enigmatic. This study tested the hypothesis that shear stress‐induced nitric oxide (NO) production participates in the regulation of matrix protein gene expression. The data presented here demonstrate that exposure of human osteoarthritic chondrocytes to a continuously applied shear stress (1.64 Pa) upregulated NO synthase gene expression and increased NO release by 1.8‐, 2.4‐, and 3.5‐fold at 2, 6, and 24 h, respectively. Exposure of chondrocytes to a short duration of shear stress for 2 h resulted in the release of accumulation of NO in the culture medium. Exposure of chondrocytes to shear stress for 2, 6, and 24 h inhibited type II collagen mRNA signal levels by 27%, 18% and 20% after a constant post‐shear incubation period of 24 h. Aggrecan mRNA signal levels were inhibited by 30%, 32% and 41% under identical conditions. Addition of an NO antagonist increased type II collagen mRNA signal levels by an average of 1.8‐fold (137% of the un‐sheared control) and reestablished the aggrecan mRNA signal levels by an average of 1.4‐fold after shear stress (92% of the un‐sheared control) (ANOVA p < 0.05). These data support the hypothesis that shear stress‐induced NO release may influence the development of degenerative joint diseases by inhibiting matrix macromolecule synthesis. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Early nerve regeneration after Achilles tendon rupture — a prerequisite for healing? A study in the rat
Authors: Ackermann Paul W. , Ahmed Mahmood , Kreicbergs Andris
Published: October 2002

Nerve regeneration during healing of Achilles tendon rupture in the rat was studied by immunohistochemistry including semiquantitative assessment. Neuronal markers for regenerating and mature fibers, ie., growth associated protein 43 (GAP‐43) and protein gene product 9.5 (PGP 9.5), respectively, were analyzed at different time points (1–16 weeks) post‐rupture. In the paratenon, both the ruptured and intact contralateral tendon (control) consistently exhibited immunoreactivity to the two neuronal markers. However, in the proper tendinous tissue only the ruptured tendon showed immunoreactivity to GAP‐43 and PGP 9.5. This expression was seen already at week 1 post‐rupture to reach a peak at week 6 followed by a successive drop till week 16. Also the occurrence of sensory and autonomic fibers according to immunoreactivity for calcitonin gene‐related peptide (CGRP) and neuropeptide Y (NPY), respectively, was analyzed. CGRP‐positivity was abundantly seen from weeks 2–6 in both perivascular and sprouting free nerve endings in the proper tendon tissue undergoing healing. NPY appeared later, at weeks 6–8 post‐rupture around blood vessels mainly located in the surrounding loose connective tissue. Apart from a role in vasoaction (CGRP, vasodilatory; NPY, vasoconstrictory), both neuropeptides have been implicated in fibroblast and endothelial cell proliferation required for angiogenesis. The present study shows that early healing of ruptured tendons is characterized by an orchestrated, temporal appearance of nerve fibers expressing peptides with different actions. The observed pattern of neuronal regeneration and neuropeptide expression may prove to be important for normal connective tissue healing. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Anisotropic properties of human tibial cortical bone as measured by nanoindentation
Authors: Fan Z. , Swadener J. G. , Rho J. Y. , Roy M. E. , Pharr G. M.
Published: October 2002

The purpose of this study was to investigate the effects of elastic anisotropy on nanoindentation measurements in human tibial cortical bone. Nanoindentation was conducted in 12 different directions in three principal planes for both osteonic and interstitial lamellae. The experimental indentation modulus was found to vary with indentation direction and showed obvious anisotropy (oneway analysis of variance test, P < 0.0001). Because experimental indentation modulus in a specific direction is determined by all of the elastic constants of cortical bone, a complex theoretical model is required to analyze the experimental results. A recently developed analysis of indentation for the properties of anisotropic materials was used to quantitatively predict indentation modulus by using the stiffness matrix of human tibial cortical bone, which was obtained from previous ultrasound studies. After allowing for the effects of specimen preparation (dehydrated specimens in nanoindentation tests vs. moist specimens in ultrasound tests) and the structural properties of bone (different microcomponents with different mechanical properties), there were no statistically significant differences between the corrected experimental indentation modulus (Mexp) values and corresponding predicted indentation modulus (Mpre) values (two‐tailed unpaired t‐test, P < 0.5). The variation of Mpre values was found to exhibit the same trends as the corrected Mexp data. These results show that the effects of anisotropy on nanoindentation measurements can be quantitatively evaluated. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Are the communists dying out in Russia?☆
Authors: Kiewiet D. Roderick , Myagkov Mikhail G.
Published: October 2002

Many predicted that the strength of the Communist Party in Russia would wane as the elderly pensioners who disproportionately supported the party died off. Contrary to this prediction, the findings of our analysis indicate that voters who reached retirement age during the past decade were even more supportive of the communists than the cohort of pensioners who preceded them. We believe this occurred because it was workers approaching retirement, not pensioners per se, who were disproportionately injured by the transition to a more market-oriented economy. Like pensioners they lost savings, but in many cases they also lost their jobs. They also had little opportunity to learn the new skills that the Russian economy increasingly calls for. There is as yet no indication that the communists have begun to die out.
Longstanding atrial fibrillation causes depletion of atrial natriuretic peptide in patients with advanced congestive heart failure
Authors: van den Berg Maarten P. , Tjeerdsma Geert , de Kam Pieter Jan , Boomsma Frans , Crijns Harry J.G.M. , van Veldhuisen Dirk J.
Published: October 2002

Background:

Congestive heart failure (CHF) is characterized by neurohormonal activation, including increased plasma concentrations of atrial natriuretic peptide (ANP) and N‐terminal ANP (N‐ANP). Onset of atrial fibrillation (AF) further increases these peptides, but it may be hypothesized that concentrations decrease during longstanding AF due to inherent atrial degeneration.

Aim:

We sought to investigate the relation between neurohormonal activation in patients with CHF and the duration of concomitant AF.

Methods:

The study group comprised 60 patients (age 70±8 years) with advanced CHF due to left ventricular systolic dysfunction (left ventricular ejection fraction (LVEF) <0.35) and chronic AF (duration 21 (1–340) months). Plasma neurohormone concentrations were measured, and multiple regression analysis was performed to identify their clinical predictors.

Results:

Median plasma neurohormone concentrations were: ANP 113 pmol/l, N‐ANP 1187 pmol/l, norepinephrine 496 pg/ml, renin 127 μunits/l, aldosterone 128 pg/ml and endothelin 8.1 pg/ml. Norepinephrine, renin, aldosterone and endothelin were not significantly related to the duration of AF. In contrast, ANP decreased along with the duration of AF (P‐0.03), while the same trend was observed for N‐ANP (P‐0.10). However, for these peptides a first order interaction with LVEF was present, which was not observed in the other neurohormones. In patients with LVEF >0.25 ANP and N‐ANP increased along with the duration of AF, whereas in patients with LVEF≤0.25 an inverse relation between ANP (P‐0.02) and N‐ANP (P‐0.04) and the duration of AF was present, longer‐standing AF being associated with lower concentrations.

Conclusion:

In patients with advanced CHF with low LVEF plasma ANP and N‐ANP concentrations decrease during longstanding AF. This finding agrees with the concept that longstanding AF leads to impaired ability of the atria to produce these neurohormones due to inherent degenerative changes.
An Unplanned Green Wave: Settlement Patterns in Sweden during the 1990s
Authors: Westlund Hans
Published: October 2002

This study focuses on the population changes in the countryside and in urban centres within the municipalities of Sweden outside the metropolitan areas, between 1990 and 1997. Overall, the countryside showed a higher population increase than the municipality centres. Smaller population centres suffered a population decline. The increase in population in the countryside was strongest in areas surrounding the metropolises and around regional centres. Statistical analysis showed that population change outside population centres mainly varies with the average income, labour-market access, and taxation values or housing costs in the municipalities. This process of change has run directly counter to the policy that was formulated for small municipalities from the end of the 1960s onwards. The growth in rural population was spontaneous for the most part, and more or less in conflict with the plans of the municipalities.
Urban Transformation in China, 1949 – 2000: A Review and Research Agenda
Authors: Ma Laurence J C
Published: October 2002

Through a review of the literature, the author identifies the achievements as well as the deficiencies in the study of China's urbanization and urbanism in the second half of the 20th century. A number of issues that merit scholarly research are suggested and the need for theorization is emphasized. During the last half century, Chinese cities underwent dramatic transformations as a consequence of two major systemic changes. During the first three decades after the socialist revolution of 1949, sustained low levels of urbanization and a brief episode of antiurbanism accompanied centralized planning and city-based industrialization. Since the economic reforms of 1978 Chinese cities have witnessed major economic and spatial shifts away from the socialist patterns. Among the many facets of urban transformation since 1978 are a more heterogeneous urban population, rural – urban migration, spatial reorganization through urban land-use change, new housing development, globalization, suburbanization, polycentric restructuring of urban form, and changes in the spatial/administrative systems of cities. It is argued that, as the Chinese economy is inherently political, political economy perspectives should be foregrounded to enrich our understanding of the complexity of China's economic and urban transformation. In this regard, the continuously powerful and multiple roles of the Party-state as the ultimate decisionmaker, regulator, and participant in the urban economy should be emphasized, despite globalization and decentralization of administrative and fiscal powers from the central to local levels. The Chinese trajectory of urban development is seen as more different from than similar to the experiences of other economies undergoing structural change away from socialism, and context-based country-specific theorization of urban change is called for. More general theories of urban transformation which are applicable to a number of former socialist nations, and which transcend the idiosyncrasies of individual countries, should be developed where possible. A closer engagement among scholars working on the urban development of China and those working on other former socialist countries is necessary if ‘the socialist city’ is to become a firm typology of cities.
China's Continuing Urban Transition
Authors: Pannell Clifton W
Published: October 2002

Urban growth in China has proceeded in step with the growth and transition of the socialist economy. Year 2000 Census data indicate an urban population of 456 million; this is 36% of the total population and is increasing much more rapidly than the overall population. Several factors drive this rapid urbanization and growth of cities and towns: continuing, although diminishing, population growth; migration of rural people, as regulations on rural and urban household registration change; rapid structural shift in employment activities and the decline of farm employment; foreign trade and foreign investment, especially in coastal areas; restructuring of state-owned enterprises and growth of private enterprises and activities; and allocation of domestic funds in fixed assets for urban infrastructure, also concentrated in coastal areas. Key issues for continuing urbanization focus on the capacity of the emerging private sector in parallel with the state and collective sectors to generate new jobs, and the willingness of the central state to reconcile the subsidies and privileges of state-sector urban employees with other recent migrants in cities and towns who do not enjoy the state-sector subsidies.
The Use of Remote Sensing and Landscape Metrics to Describe Structures and Changes in Urban Land Uses
Authors: Herold Martin , Scepan Joseph , Clarke Keith C
Published: October 2002

Remote sensing technology has great potential for acquisition of detailed and accurate land-use information for management and planning of urban regions. However, the determination of land-use data with high geometric and thematic accuracy is generally limited by the availability of adequate remote sensing data, in terms of spatial and temporal resolution, and digital image analysis techniques. This study introduces a methodology using information on image spatial form—landscape metrics—to describe urban land-use structures and land-cover changes that result from urban growth. The analysis is based on spatial analysis of land-cover structures mapped from digitally classified aerial photographs of the urban region Santa Barbara, CA. Landscape metrics were calculated for segmented areas of homogeneous urban land use to allow a further characterization of the land use of these areas. The results show a useful separation and characterization of three urban land-use types: commercial development, high-density residential, and low-density residential. Several important structural land-cover features were identified for this study. These were: the dominant general land cover (built up or vegetation), the housing density, the mean structure and plot size, and the spatial aggregation of built-up areas. For two test areas in the Santa Barbara region, changes (urban growth) in the urban spatial land-use structure can be described and quantified with landscape metrics. In order to discriminate more accurately between the three land-cover types of interest, the landscape metrics were further refined into what are termed ‘landscape metric signatures’ for the land-use categories. The analysis shows the importance of the spatial measurements as second-order image information that can contribute to more detailed mapping of urban areas and towards a more accurate characterization of spatial urban growth pattern.
A GIS-Based Decision-Support Tool for Public Facility Planning
Authors: Ribeiro Alexandra , Antunes António Pais
Published: October 2002

The installation and operation of public facilities, such as schools or hospitals, involve important amounts of public spending, and therefore need to be carefully planned. Research efforts made since the early 1960s led to the development of a rich collection of optimization models and solution methods for public facility planning problems. It must be recognized, however, that the practical impact of the efforts made up to now is rather weak. This paper presents an interactive, user-friendly decision-support tool for public facility planning where the capabilities of geographic information systems and advanced optimization methods are put together. We hope that it will contribute to bridge the gap between research and practice that characterizes the way public facility planning is made at present. The application of the decision-support tool is illustrated for a real-world setting.
Design of Decision Support for Stakeholder-Driven Collaborative Land Valuation
Authors: O'Connell Ian J , Keller C Peter
Published: October 2002

First Nations treaty negotiations and land-claim settlements require the valuation of large areas of land for diverse land uses, including usage which is difficult to quantify in absolute or monetary terms. The authors report an attempt to develop a methodology for seeking consensus on land values for the latter land-use activities, using Gestalt valuation. They offer an alternative to planner-driven land valuation, placing the valuation responsibility instead on stakeholders. The methodology is justified and explained. The authors introduce different types of decision-support information products that can be derived to facilitate consensus building. They summarise experience gained in an evaluation of the proposed methodological procedure, in which university students were used as a sample. They conclude that computing technology has advanced sufficiently to make it reasonably straightforward to collect information about individual stakeholders' land valuations, and that the resultant information can be packaged effectively in a collaborative spatial decision support system to facilitate consensus building. Ongoing research is introduced.
Button Design for Map Overlays: 2
Authors: Diao Yuanan , Xiang Wei-Ning
Published: October 2002

A new approach to button design has recently been proposed that uses natural segments, instead of even intervals, on the weight value range in determining the number of tabs that should be incorporated in a button system and the value each button carries. Button systems so designed do not have the problems of redundancy and underrepresentation that are common to the conventionally designed button systems. Presently limited to the map overlays that involve only two parent maps, this approach is extended to the case of three parent maps in this paper.
Entity-Based Modeling of Urban Residential Dynamics: The Case of Yaffo, Tel Aviv
Authors: Benenson Itzhak , Omer Itzhak , Hatna Erez
Published: October 2002

The dynamics of the ethnic residential distribution in the Yaffo area of Tel Aviv, which is jointly occupied by Arab and Jewish residents, is simulated by means of an entity-based (EB) model. EB models consider householders as separate entities, whose residential behavior is defined by the properties of the surrounding infrastructure and of other householders. The power of the EB approach lies in its ability to interpret directly different forms of decisionmaker behavior in the model's terms. Several scenarios of residential interactions between members of local ethnic groups are compared on the basis of detailed georeferenced data taken from Israel's 1995 Population Census. The model simulates very closely the residential dynamics during the period 1955–95; the importance of the qualitative aspects of residential choice, as captured by the EB approach, is demonstrated by this correspondence.
Mapping Schengenland: Denaturalizing the Border
Authors: Walters William
Published: October 2002

In this paper I examine the reorganization of border controls associated with the Schengen process in the European Union and some of its close neighbours. Rather than asking the political science question of why states are committed to Schengen (or not, in the case of the United Kingdom and Ireland), I interpret Schengen as a political moment for genealogical reflection and analysis. The purpose is to contribute to a more historicized understanding of borders. Schengen is analyzed in terms of three trajectories, each of which allows us to denaturalize certain key aspects of the border, such as its identity, function, rationality, and contingency. Schengen is theorized in relation to the geopolitical border, the national border, and the biopolitical border. Other possibilities for genealogies of the border are also canvassed.
From Seattle (and Ubon) to Bangkok: The Scales of Resistance to Corporate Globalization
Authors: Glassman Jim
Published: October 2002

Recent work by geographers has highlighted attempts by local groups to ‘jump scales’ in their efforts to contest the power of global capital. Sometimes such ‘scale jumping’ is also seen as part of an effort to bypass the nation-state. This paper explores a particular case of scale jumping, which illustrates some of the complexities of the process. Building on the anticorporate globalization momentum generated during the ‘battle in Seattle’ and the demonstrations during the February 2000 United Nations Commission on Trade and Development meetings in Bangkok, local antidam activists from Ubon Ratchathani province in Thailand scaled up their activities during 2000, utilizing various international connections to improve their visibility and strengthen their prospects for success. Rather than simply bypassing the nation-state, however, they have had to use both local and international resources to try to combat the policies of the nation-state, a project in which they have had real but still contested success. The case of antidam activism in Ubon Ratchathani illustrates some of the nuances of ‘globalization from below’, as well as the continuing power and relevance of the nation-state as a site of struggle.
Blur Discrimination and its Relation to Blur-Mediated Depth Perception
Authors: Mather George , Smith David R R
Published: October 2002

Retinal images of three-dimensional scenes often contain regions that are spatially blurred by different amounts, owing to depth variation in the scene and depth-of-focus limitations in the eye. Variations in blur between regions in the retinal image therefore offer a cue to their relative physical depths. In the first experiment we investigated apparent depth ordering in images containing two regions of random texture separated by a vertical sinusoidal border. The texture was sharp on one side of the border, and blurred on the other side. In some presentations the border itself was also blurred. Results showed that blur variation alone is sufficient to determine the apparent depth ordering. A subsequent series of experiments measured blur-discrimination thresholds with stimuli similar to those used in the depth-ordering experiment. Weber fractions for blur discrimination ranged from 0.28 to 0.56. It is concluded that the utility of blur variation as a depth cue is constrained by the relatively mediocre ability of observers to discriminate different levels of blur. Blur is best viewed as a relatively coarse, qualitative depth cue.
Propagation of Depth Information from Local Regions in 3-D Scenes
Authors: Sauer Craig W , Braunstein Myron L , Saidpour Asad , Andersen George J
Published: October 2002

The effects of regions with local linear perspective on judgments of the depth separation between two objects in a scene were investigated for scenes consisting of a ground plane, a quadrilateral region, and two poles separated in depth. The poles were either inside or outside the region. Two types of displays were used: motion-parallax dot displays, and a still photograph of a real scene on which computer-generated regions and objects were superimposed. Judged depth separations were greater for regions with greater linear perspective, both for objects inside and outside the region. In most cases, the effect of the region's shape was reduced for objects outside the region. Some systematic differences were found between the two types of displays. For example, adding a region with any shape increased judged depth in motion-parallax displays, but only high-perspective regions increased judged depth in real-scene displays. We conclude that depth information present in local regions affects perceived depth within the region, and that these effects propagate, to a lesser degree, outside the region.
Representing Motion in a Static Image: Constraints and Parallels in Art, Science, and Popular Culture
Authors: Cutting James E
Published: October 2002

Representing motion in a picture is a challenge to artists, scientists, and all other imagemakers. Moreover, it presents a problem that will not go away with electronic and digital media, because often the pedagogical purpose of the representation of motion is more important than the motion itself. All satisfactory solutions evoke motion—for example, dynamic balance (or broken symmetry), stroboscopic sequences, affine shear (or forward lean), and photographic blur—but they also typically sacrifice the accuracy of the motion represented, a solution often unsuitable for science. Vector representations superimposed on static images allow for accuracy, but are not applicable to all situations. Workable solutions are almost certainly case specific and subject to continual evolution through exploration by imagemakers.
The Role of ON- and OFF-Channel Processing in the Detection of Bilateral Symmetry
Authors: Brooks Anna , van der Zwan Rick
Published: October 2002

We present evidence that grouping for luminance does not take precedence over the detection of bilaterally symmetrical patterns. Using single-axis and double-axis images, we found that element pairs within which luminance is held constant drive symmetry-detection mechanisms more effectively than pairs within which luminance varies. Moreover, the performance decrement observed for patterns defined by element pairs within which luminance varies is not specific to interchannel variation. Luminance variation within the ON and OFF channels has the same effect as variation between the channels on the performance of axis-orientation identification tasks. It is argued that this constitutes possible evidence for subchannels within the ON and OFF channels. One of the characteristics of the subchannels is that each processes only a limited range of luminance steps. The implications of this type of luminance processing for the detection of symmetry in the visual scene are discussed.
Spatial but Not Temporal Cueing Influences the Mislocalisation of a Target Flashed during Smooth Pursuit
Authors: Rotman Gerben , Brenner Eli , Smeets Jeroen B J
Published: October 2002

Human subjects misjudge the position of a target that is flashed during a pursuit eye movement. Their judgments are biased in the direction in which the eyes are moving. We investigated whether this bias can be reduced by making the appearance of the flash more predictable. In the normal condition, subjects pursued a moving target that flashed somewhere along its trajectory. After the presentation, they indicated where they had seen the flash. The mislocalisations in this condition were compared to mislocalisations in conditions in which the subjects were given information about when or where the flash would come. This information consisted of giving two warning flashes spaced at equal intervals before the target flash, of giving two warning beeps spaced at equal intervals before the target flash, or of showing the same stimulus twice. Showing the same stimulus twice significantly reduced the mislocalisation. The other conditions did not. We interpret this as indicating that it is not predictability as such that influences the performance, but the fact that the target appears at a spatially cued position. This was supported by a second experiment, in which we examined whether subjects make smaller mis-judgments when they have to determine the distance between a target flashed during pursuit and a reference seen previously, than when they have to determine the distance between the flashed target and a reference seen afterwards. This was indeed the case, presumably because the reference provided a spatial cue for the flash when it was presented first. We conclude that a spatial cue reduces the mislocalisation of targets that are flashed during pursuit eye movements. The cue does not have to be exactly at the same position as the flash.
An intracellular signaling hierarchy determines direction of migration in opposing chemotactic gradients
Authors: Heit Bryan , Tavener Samantha , Raharjo Eko , Kubes Paul
Published: October 2002

Neutrophils must follow both endogenous and bacterial chemoattractant signals out of the vasculature and through the interstitium to arrive at a site of infection. By necessity, in the setting of multiple chemoattractants, the neutrophils must prioritize, favoring end target chemoattractants (e.g., fMLP and C5a) emanating from the site of infection over intermediary endogenous chemoattractants (e.g., IL-8 and LTB4) encountered en route to sites of infection. In this study, we propose a hierarchical model of two signaling pathways mediating the decision-making process of the neutrophils, which allows end target molecules to dominate over intermediary chemoattractants. In an under agarose assay, neutrophils predominantly migrated toward end target chemoattractants via p38 MAPK, whereas intermediary chemoattractant-induced migration was phosphoinositide 3-kinase (PI3K)/Akt dependent. When faced with competing gradients of end target and intermediary chemoattractants, Akt activation was significantly reduced within neutrophils, and the cells migrated preferentially toward end target chemoattractants even at 1/1,000th that of intermediary chemoattractants. End target molecules did not require chemotactic properties, since the p38 MAPK activator, LPS, also inhibited Akt and prevented migration to intermediary chemoattractants. p38 MAPK inhibitors not only reversed this hierarchy, such that neutrophils migrated preferentially toward intermediary chemoattractants, but also allowed neutrophils to be drawn out of a local end target chemoattractant environment and toward intermediary chemoattractants unexpectedly in an exaggerated (two- to fivefold) fashion. This was entirely related to significantly increased magnitude and duration of Akt activation. Finally, end target chemoattractant responses were predominantly Mac-1 dependent, whereas nondominant chemoattractants used primarily LFA-1. These data provide support for a two pathway signaling model wherein the end target chemoattractants activate p38 MAPK, which inhibits intermediary chemoattractant-induced PI3K/Akt pathway, establishing an intracellular signaling hierarchy.
Bone morphogenetic protein and retinoic acid signaling cooperate to induce osteoblast differentiation of preadipocytes
Authors: Skillington Jeremy , Choy Lisa , Derynck Rik
Published: October 2002

Mesenchymal cells can differentiate into osteoblasts, adipocytes, myoblasts, or chondroblasts. Whether mesenchymal cells that have initiated differentiation along one lineage can transdifferentiate into another is largely unknown. Using 3T3-F442A preadipocytes, we explored whether extracellular signals could redirect their differentiation from adipocyte into osteoblast. 3T3-F442A cells expressed receptors and Smads required for bone morphogenetic protein (BMP) signaling. BMP-2 increased proliferation and induced the early osteoblast differentiation marker alkaline phosphatase, yet only mildly affected adipogenic differentiation. Retinoic acid inhibited adipose conversion and cooperated with BMP-2 to enhance proliferation, inhibit adipogenesis, and promote early osteoblastic differentiation. Expression of BMP-RII together with BMP-RIA or BMP-RIB suppressed adipogenesis of 3T3-F442A cells and promoted full osteoblastic differentiation in response to retinoic acid. Osteoblastic differentiation was characterized by induction of cbfa1, osteocalcin, and collagen I expression, and extracellular matrix calcification. These results indicate that 3T3-F442A preadipocytes can be converted into fully differentiated osteoblasts in response to extracellular signaling cues. Furthermore, BMP and retinoic acid signaling cooperate to stimulate cell proliferation, repress adipogenesis, and promote osteoblast differentiation. Finally, BMP-RIA and BMP-RIB induced osteoblast differentiation and repressed adipocytic differentiation to a similar extent.
The yeast DHHC cysteine-rich domain protein Akr1p is a palmitoyl transferase
Authors: Roth Amy F. , Feng Ying , Chen Linyi , Davis Nicholas G.
Published: October 2002

Protein palmitoylation has been long appreciated for its role in tethering proteins to membranes, yet the enzymes responsible for this modification have eluded identification. Here, experiments in vivo and in vitro demonstrate that Akr1p, a polytopic membrane protein containing a DHHC cysteine-rich domain (CRD), is a palmitoyl transferase (PTase). In vivo, we find that the casein kinase Yck2p is palmitoylated and that Akr1p function is required for this modification. Akr1p, purified to near homogeneity from yeast membranes, catalyzes Yck2p palmitoylation in vitro, indicating that Akr1p is itself a PTase. Palmitoylation is stimulated by added ATP. Furthermore, during the reaction, Akr1p is itself palmitoylated, suggesting a role for a palmitoyl-Akr1p intermediate in the overall reaction mechanism. Mutations introduced into the Akr1p DHHC-CRD eliminate both the trans- and autopalmitoylation activities, indicating a central participation of this conserved sequence in the enzymatic reaction. Finally, our results indicate that palmitoylation within the yeast cell is controlled by multiple PTase specificities. The conserved DHHC-CRD sequence, we propose, is the signature feature of an evolutionarily widespread PTase family.
Application of regularisation method of quasi‐singular integrals to compute eddy current distribution near cracks
Authors: Beltrame Philippe , Burais Noel
Published: October 2002

For thin cracks, in eddy current testing (ECT), the field‐flaw interaction is equivalent to a current dipole layer on its surface. The dipole density is the solution of an integral equation with a hyperstrong kernel. The variation of coil impedance and eddy current distribution is directly obtained from this density by a surface integration. There is a numerical difficulty to evaluate accurately integrals for the current density near the crack. In fact, due to the singular kernel of a dyadic Green function, the integration is quasi‐singular. A specific regularisation algorithm is developed to overcome this problem and applied to represent eddy current distribution between two cracks.