bluuebunny/crossref_metadata_2025 huggingface dataset:
Medulloblastoma in the second decade of life: A specific group with respect to toxicity and management
Authors: Tabori Uri , Sung Lillian , Hukin Juliette , Laperriere Normand , Crooks Bruce , Carret Anne‐Sophie , Silva Mariana , Odame Isaac , Mpofu Chris , Strother Douglas , Wilson Beverly , Samson Yvan , Bouffet Eric ,   Canadian Pediatric Brain Tumor Consortium
Published: March 2005

BACKGROUND

Most reported data of chemoradiotherapy protocols for the treatment of medulloblastoma describe children who were treated in the first decade of life. To consider the feasibility of this approach in adolescents, the authors studied their clinical course with specific emphasis on toxicity, tolerability, and prognosis.

METHODS

In this retrospective study, the authors examined the toxicity profiles and outcomes of children age 10–20 years with medulloblastoma who were treated at centers throughout Canada between 1986 and 2003. Detailed toxicity data from 2 chemotherapy protocols were collected for teenagers and were compared with data from a group of control patients age 5–10 years.

RESULTS

In total, 72 teenagers were analyzed. Grade ≥ 2 ototoxicity and neurotoxicity occurred in 45% and 71% of chemotherapy‐treated patients, respectively. Grade 3–4 hematotoxicty occurred in 95% of patients. Toxicity resulted in delay of treatment for 73% of patients and dose modification in 75% of patients, including protocol discontinuation in 25% of patients. Weight loss > 10% was encountered in 73% of patients and required intervention in 45% of patients. Teenagers had significantly more hematotoxicity and neurotoxicity compared with controls on both chemotherapeutic protocols. Ototoxicity was similar in both age groups. Toxicity resulted in significantly more treatment delays and dose modifications in teenager patients compared with controls. The 5‐year overall and event‐free survival rates (± standard deviation) were 78% ± 6% and 70% ± 6%, respectively. The mean time (± standard deviation) to disease recurrence was 3.2 ± 2.2 years.

CONCLUSIONS

The increased toxicity rate and high incidence of treatment modifications in this study suggested that current pediatric protocols may require modifications for teenagers with medulloblastoma. The results highlighted several issues that should be addressed in future prospective trials. Cancer 2005. © 2005 American Cancer Society.
On the effects of nodal distributions for imposition of essential boundary conditions in the MLPG meshfree method
Authors: Augarde C. E. , Deeks A. J.
Published: March 2005

Imposition of essential boundary conditions in meshfree methods is made difficult because the shape functions used do not possess the ‘delta’ property. Various procedures have been proposed including penalty, Lagrange multipliers and collocation. It is shown in this paper that the success of a procedure depends on the arrangement of the nodal points. Certain methods of imposing boundary conditions are shown not to work for unstructured nodal arrangements. Much previous work has been demonstrated using structured grids thus hiding these drawbacks. Copyright © 2005 John Wiley & Sons, Ltd.
On the design of bandwidth efficient signalling for indoor wireless optical channels
Authors: Hranilovic Steve
Published: March 2005

It is well known that indoor wireless optical channels are limited not only in transmitted optical power, but also in signalling bandwidth. This bandwidth constraint arises due to multipath dispersion in indoor settings as well as due to response time limitations of optoelectronic components.

This paper presents an overview of theoretical and practical issues in the design of signalling for bandwidth constrained intensity modulated, direct detection wireless optical channels. A brief overview of the salient qualities of the wireless optical channel are presented to highlight the amplitude constraints which arise. A survey of modulation design is then presented which includes the review of a general technique to represent optical intensity modulation in a signal space and to construct optical intensity lattice codes. Results on the channel capacity of indoor wireless optical channels are surveyed and particular emphasis is placed on recently derived asymptotically exact bounds. The use of multiple emitters and receivers in wireless optical channels is also presented and particular emphasis is placed on techniques which exploit spatial dimensions to improve spectral performance. The paper concludes with some remarks regarding the status of the research area and suggestions for future work. Copyright © 2005 John Wiley & Sons, Ltd.
Packet delay analysis of the advanced infrared (AIr) CSMA/CA MAC protocol in optical wireless LANs
Authors: Chatzimisios P. , Boucouvalas A. C.
Published: March 2005

During the past few years the wireless technology market has experienced a tremendous growth. Users today expect to be able to communicate and access data anytime, anywhere, using almost any portable device. Infrared Data Association (IrDA) addressed the requirement for indoor multipoint wireless connectivity with the development of the advanced infrared (AIr) protocol stack utilizing the infrared spectrum. AIr medium access control (MAC) protocol employs a carrier sensing multiple access with collision avoidance (CSMA/CA) protocol in addition to a request to send/clear to send (RTS/CTS) packet exchange reservation scheme and a linear adjustment of the contention window (CW). This paper develops a new modelling approach to evaluate saturation performance of the AIr protocol based on conditional probability arguments rather than bi‐dimensional Markov chains. Moreover, we extend performance studies in former literature papers by providing an intuitive AIr packet delay analysis assuming error‐free transmissions and a fixed number of stations. Using OPNET simulation results, we validate our mathematical analysis and we show that the proposed model predicts AIr packet delay performance very accurately. Utilizing the derived mathematical analysis, we determine the significance of both link layer and physical parameters, such as burst size, minimum CW size value and minimum turnaround time on AIr packet delay performance. Finally, we propose suitable values for both backoff and protocol parameters that reduce average packet delay and, thus, maximize performance. Copyright © 2005 John Wiley & Sons, Ltd.
Comparing the streaming of FGS encoded video at different aggregation levels: frame, GoP, and scene
Authors: de Cuetos Philippe , Seeling Patrick , Reisslein Martin , Ross Keith W.
Published: March 2005

Fine granularity scalability (FGS), a new coding technique that has recently been added to the MPEG‐4 video coding standard, allows for the flexible scaling of each individual video frame at very fine granularity. This flexibility makes FGS video very well suited for rate‐distortion optimized streaming mechanisms, which minimize the distortion (i.e. maximize the quality) of the streamed video by transmitting the optimal number of bits for each individual frame. The per‐frame optimization of the transmission schedule, however, puts a significant computational burden on video servers and intermediate streaming gateways. In this paper we investigate the rate‐distortion optimized streaming at different video frame aggregation levels. We find that compared to the optimization for each individual video frame, optimization at the level of video scenes reduces the computational effort dramatically, while reducing the video quality only very slightly. Copyright © 2005 John Wiley & Sons, Ltd.
Sox10 overexpression induces neural crest‐like cells from all dorsoventral levels of the neural tube but inhibits differentiation
Authors: McKeown Sonja J. , Lee Vivian M. , Bronner‐Fraser Marianne , Newgreen Donald F. , Farlie Peter G.
Published: March 2005

SoxE genes (Sox8, Sox9, and Sox10) are early response genes to neural crest induction. Although the early role of Sox9 has been examined in chick and frog, later roles in neural crest migration and differentiation remain largely unexplored. We first examined which SoxE genes were expressed in trunk neural crest cells and then investigated their function using in ovo electroporation. The results of this analysis reveal that Sox10 is present in migrating neural crest cells, whereas other SoxE genes are only expressed transiently after induction. Ectopic expression of Sox10 in the neural tube at trunk level induced expression of HNK‐1 in neuroepithelial cells followed by extensive emigration from all levels of the dorsoventral neuraxis, including the floor plate. Sox10‐expressing cells failed to express neuronal, Schwann, or melanocyte markers up to 6 days posttransfection (E8), suggesting these cells were maintained in an undifferentiated state. Overexpression of Sox8 or Sox9 had similar but not identical effects on neuroepithelial cells. These results show that high levels of Sox10, Sox9, or Sox8 expression in the neural tube are capable of inducing a migratory neural crest‐like phenotype even in the absence of dorsal signals and can maintain these cells in an undifferentiated state. Developmental Dynamics 233:430–444, 2005. © 2005 Wiley‐Liss, Inc.
Damaging‐agent sensitivity of Artemis‐deficient cell lines
Authors: Musio Antonio , Marrella Veronica , Sobacchi Cristina , Rucci Francesca , Fariselli Laura , Giliani Silvia , Lanzi Gaetana , Notarangelo Luigi D. , Delia Domenico , Colombo Roberto , Vezzoni Paolo , Villa Anna
Published: March 2005

Defects in repairing double‐strand breaks can lead to genome instability and tumorigenesis. In humans, most T–B– severe combined immunodeficiencies (SCID) have a defect in either the RAG1 or RAG2 gene, are not radiosensitive and do not show genome instability. On the contrary, a minority of T–B– SCID patients have abnormalities in the Artemis gene and are moderately radiosensitive. Artemis‐deficient cells are unable to process hairpin ends after RAG cleavage, but hairpin opening activity alone does not explain the moderate X‐ray sensitivity of Artemis‐deficient cells. We report here that, at variance with what has been described in mice, cell lines from Artemis–/– patients are moderately sensitive to mitomycin C and show only a low to moderate increase in genomic instability, both spontaneously and after exposure to ionizing radiations. There is some heterogeneity in the levels of DNA damage sensitivity and genome instability, which could in part be due to different effects of the specific mutation involved or to genetic background, which may not always represent null alleles. This data supports the hypothesis that, in addition to playing a role in hairpin opening during the V(D)J recombination process, Artemis is involved in the repair of a subset of DNA damage whose exact nature is still undefined.
Tolerization of dendritic cells by HLA‐G
Authors: Ristich Vladimir , Liang Siyuan , Zhang Wei , Wu Juan , Horuzsko Anatolij
Published: March 2005

The expression of HLA‐G at the fetal‐maternal interface during pregnancy and in transplanted tissue makes this a key molecule in the acceptance of a semiallogeneic fetus and allogeneic transplant. Dendritic cells (DC) play a critical role in the control of innate and adaptive immune responses. DC are present in maternal decidua, but must be kept under tight control. Here we describe the mechanism of tolerization of DC by HLA‐G through inhibitory receptor interactions. The HLA‐G‐ILT (immunoglobulin‐like transcript) interaction leads to development of tolerogenic DC with the induction of anergic and immunosuppressive T cells. Using human monocyte‐derived DC and ILT4‐transgenic mice, we show that (i) HLA‐G induces the development of tolerogenic DC with arrest maturation/activation of myeloid DC, (ii) HLA‐G‐modified DC induce differentiation of anergic and immunosuppressive CD4+ and CD8+ effector T cells, and (iii) the gene expression profile provides evidence that HLA‐G induces tolerogenic DC by disruption of the MHC class II presentation pathway. Ligation of ILT4 receptor on DC from transgenic mice diminished peptide presentation by MHC class II molecules and significantly prolonged allograft survival. These findings provide support that HLA‐G is an important tolerogenic molecule on DC for the acceptance of a semiallogeneic fetus and transplanted tissue/organ.
Catalytic Properties of a MnIII‐Salen Complex Immobilised in a Pillared Clay by Simultaneous Pillaring/Encapsulation Procedures
Authors: Cardoso Beatriz , Pires João , Carvalho Ana P. , Carvalho Manuela B. , Kuźniarska‐Biernacka Iwona , Silva Ana R. , Freire Cristina , de Castro Baltazar
Published: March 2005

The simultaneous encapsulation of a manganese(III)‐salen complex, [Mn(salhd)Cl], and pillaring of a montmorillonite clay with aluminium polyoxycations was performed using two methods: method A – the [Mn(salhd)Cl] complex was dissolved in ethanol and added to the oligomer solution at a stage when the oligomeric species had already formed; method B – the complex, also dissolved in ethanol, was added to the clay dispersion. After calcination, both materials were Soxhlet extracted to remove the excess complex, and characterised by XRD, nitrogen adsorption at –196 °C, XPS, atomic absorption and FTIR spectroscopy. In both cases, the manganese(III)‐salen complex is mainly physically entrapped within the matrix, although some host–guest interactions with the matrix may be present. Both new materials [Mn(salhd)Cl]@Al‐WYO_A and [Mn(salhd)Cl]@Al‐WYO_B show catalytic activity in the epoxidation of styrene at room temperature with PhIO as oxygen source in acetonitrile. The solids present high styrene epoxide selectivity, and may be reused at least four times. FTIR spectra of the catalysts after the catalytic reactions suggest that during the reaction no structural changes of the pillared clay (PILC) took place, but low extent complex leaching occurred. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Two Novel Transition‐Metal Phosphite Compounds with 4‐, 6‐ and 12‐Membered Rings: Hydrothermal Syntheses, Crystal Structures and Magnetic Properties of Na2[M(HPO3)2] (M = Fe, Co)
Authors: Liu Wei , Chen Hao‐Hong , Yang Xin‐Xin , Zhao Jing‐Tai
Published: March 2005

Two transition‐metal phosphites, Na2[M(HPO3)2] (M = Fe, Co) with a new structure type have been synthesised under mild hydrothermal conditions and the solid‐state structures have been elucidated by single‐crystal X‐ray diffraction studies. The structures are of a new type with the following data: orthorhombic, Pnma, a = 12.169(4), b = 5.441(2) and c = 9.146(3) Å for the iron species 1 and a = 12.091(3), b = 5.400(4) and c = 9.115(2) Å for the cobalt compound 2, with Z = 4. The crystal structures of these compounds are isotypic and built up from a 3D open framework with 4‐, 6‐ and 12‐membered polyhedral rings of vertex‐linked MO6 and HPO3 building units. The inorganic frameworks contains 12‐membered ring channel systems in which the sodium ions are located. The topology of this structure type is remarkably similar to that of the aeschynite CaTa2O6 with much larger channels. Magnetic measurements of Na2[Co(HPO3)2] show different magnetic features in the low‐temperature (5–30 K) and high‐temperature ranges (100–320 K) suggesting the possible existence of a complex magnetic structure. Antiferromagnetic ordering can be observed as a broadened cusp in χ–1 at θ = 2.6 K. For Na2[Fe(HPO3)2], the magnetic behavior follows the Curie–Weiss law with μeff = 5.41 μB, fitted for 100–320 K. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Coordination Chemistry of the Ditopic Ligand 4‐[6‐(2‐Pyridyl)‐2‐pyridyl]‐6‐(2‐pyridyl)pyrimidine: Encapsulation of Nitrate by [2 × 2]Grid Complexes
Authors: Kovbasyuk Larisa , Pritzkow Hans , Krämer Roland
Published: March 2005

We describe herein the synthesis, physical properties and crystal structures of metal complexes with the new ligand 6‐(2‐pyridyl)‐4‐[6‐(2‐pyridyl)‐2‐pyridyl]pyrimidine (L). Reactions of L with NiII, CoII, FeII, ZnII and CuII nitrates in a 1:1 ratio leads to the self‐assembled tetranuclear [2 × 2] grid complexes 1–5 with encapsulated NO3– ions, as confirmed by the X‐ray crystal structures of [Ni4L4(DMSO)2(H2O)2](NO3)(ClO4)7·4 DMSO·6 H2O (1) and [Co4L4(DMF)4](NO3)(ClO4)7 (2). The mononuclear copper(I) complex [CuL(PPh3)2]‐ClO4·2 (CH3CN) (6) and the binuclear [Cu2L2(CN)(PPh3)2]‐ClO4 (7) were synthesized from L and [Cu(PPh3)3]Cl. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Complexation of Charged Porphyrins by Charged and Metal‐Chelated EDTA‐Tethered β‐Cyclodextrin Dimers: A Thermodynamic Study on the Influence of Tether Charge and Flexibility on Binding Affinity
Authors: Mulder Alart , Huskens Jurriaan , Reinhoudt David N.
Published: March 2005

Complex formation between charged porphyrin guests and charged or neutral β‐cyclodextrin (CD) host dimers linked by ethylenediamine‐N,N,N,N‐tetraacetate (EDTA) tethers was assessed by microcalorimetry. Two EDTA‐tethered CD dimers (1 and 2) were employed to obtain a series of structurally similar CD dimers with different tether charges and flexibilities through either (partial) protonation or metal chelation (with CaII or EuIII) of the EDTA tether. Both the tether charge and the flexibility of the CD dimers strongly influenced the binding properties, giving rise to binding constants differing by factors of up to 22. The effect of tether charge was elucidated by the complexation of tetraanionic meso‐tetrakis(4‐sulfonatophenyl)porphyrin (TSPP) by the different forms of CD dimer 1. Tether charge‐dependent complex (de)solvation gave rise to large systematic and counteracting changes in binding enthalpy and entropy, resulting in a binding affinity for the positively charged europium complex of the CD dimer five times larger than that of the negatively charged free li‐gand CD dimer. No marked differences in binding affinities were observed for the complexation of TSPP by CD dimer 2. Both restricted tether flexibility by metal chelation and repulsive electrostatic interactions resulted in diminished binding affinity of CD dimer 1 for the relatively large tetracationic p‐tert‐butylbenzyl‐functionalized p‐pyridylporphyrin (TBPyP). The europium complex of CD dimer 1 binds TBPyP less strongly than the corresponding negatively charged uncomplexed forms of the CD dimer, by a factor of up to 22. The tether of CD dimer 2 is too short to allow strong binding of TBPyP. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Natural recovery from accelerated forest ditch and stream bank erosion five years after harvesting of plantation forest on Plynlimon, mid‐Wales
Authors: Stott Tim
Published: March 2005

Erosion rates surveyed using 230 erosion pins on 24 occasions over eight years (1994–2001) on forested stream banks, tributaries and forest ditches in the 0·89 km2Nant Tanllwyth catchment, part of the Hafren Forest on Plynlimon, mid‐Wales, showed statistically significant increases of up to 40 mm a−1in mean erosion rates during the two‐year period in which environmentally sensitive plot‐scale timber harvesting operations took place (1996–97). In the four years following timber harvesting mean erosion rates at all sites recovered to levels that were lower than before the harvesting operations began. This is attributed to increased light levels, following canopy removal, allowing vegetation to colonize exposed banks. There was a statistically significant relationship (p< 0·05) between mean erosion rate in 2000–01 (four years after harvesting) and percentage vegetation cover at erosion monitoring sites in the clearfelled (south tributaries) area though the same relationship did not hold for sites on the mainstream banks or for sites on the north (mature forest) ditch sites. The implications of natural vegetation colonization for management of such streams are discussed. Copyright © 2005 John Wiley & Sons, Ltd.
Application of supplementary flow in comprehensive 2D liquid chromatography combining SEC and RPC
Authors: Winther Bjørn , Reubsaet J. Léon E.
Published: March 2005

A comprehensive two‐dimensional HPLC system (SEC×RPC) was evaluated. Various model compounds with differing hydrophobicity (log D: –0.08 to 2.22) and size (MW: 194 to 66.0×103) were used. In order to reduce the run time of the second dimension, and thereby optimize the number of runs per unit volume from the first dimension, short RPC columns were used (7.5 mm). This column size demanded a low concentration of methanol in the mobile phase from the first dimension, in order to avoid severe band broadening and solute loss. Secondary interactions on SEC make a high methanol concentration in the mobile phase a necessity. Up to 40% methanol was required to diminish non‐ideal SEC behavior. These conditions were non‐compatible with trapping of hydrophilic compounds on RPC. The use of a supplementary flow (0.1% TFA) mixed after the first dimension led to better peak shape and trapping of hydrophilic compounds in the second dimension. This demanded flow adjustment in SEC, which in turn caused performance improvement and an increase in analysis time, making more RPC separations possible. These factors contributed to a larger peak capacity.
Reversible Superhydrophobicity to Superhydrophilicity Transition by Extending and Unloading an Elastic Polyamide Film
Authors: Zhang Jilin , Lu Xiaoying , Huang Weihuan , Han Yanchun
Published: March 2005

Summary: Reversible switching between superhydrophobic and superhydrophilic wettability of a polyamide film with a triangular net‐like structure can be achieved by biaxially extending and unloading the elastic film. Both the change of the average side‐length of the triangular net‐like structure upon biaxial extension and unloading, and the surface tension of the water droplet, are believed to be responsible for the reversible switching between superhydrophobicity and superhydrophilicity.

Change in structure and wettability of the triangular net‐like polyamide film upon extension and unloading.

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Change in structure and wettability of the triangular net‐like polyamide film upon extension and unloading.
A continuous‐time strategic capacity planning model
Authors: Huh Woonghee Tim , Roundy Robin O.
Published: March 2005

Capacity planning decisions affect a significant portion of future revenue. In the semiconductor industry, they need to be made in the presence of both highly volatile demand and long capacity installation lead‐times. In contrast to traditional discrete‐time models, we present a continuous‐time stochastic programming model for multiple resource types and product families. We show how this approach can solve capacity planning problems of reasonable size and complexity with provable efficiency. This is achieved by an application of the divide‐and‐conquer algorithm, convexity, submodularity, and the open‐pit mining problem. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.
Oxygen transport as a solid‐state structure probe for polymeric materials: A review
Authors: Hiltner A. , Liu R. Y. F. , Hu Y. S. , Baer E.
Published: March 2005

In the quest to elucidate the solid‐state structures of polymers, insight into the amorphous phase is particularly elusive. Although the permeability of small molecules is often measured as an important performance property, numerous researchers have found that a deeper analysis of the transport characteristics provides insight into polymer morphology, especially if used in combination with more usual characterization techniques. The transport of small gas molecules senses the permeable amorphous structure and probes the nature of the free volume. In recent years, our interest in the gas barrier of polyesters has resulted in an unusual opportunity to investigate the nature of the free volume in the polymer glassy state. This effort has been aided by access to aromatic polyesters with designed variations in their chemical structure. This review focuses on oxygen transport, supplemented with other methods of physical analysis, as a probe of the excess‐hole free volume. The review addresses the profound effects of orientation and crystallization on the free volume of the glassy state. The discussion also presents a simple odel for the gas permeability of the isotropic glass based on lattice concepts and tests more sophisticated models for the gas permeability of semicrystalline polymers. The final section addresses other opportunities for fruitful applications of oxygen transport as a solid‐state structure probe. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1047–1063, 2005
Biotic and abiotic processes on granite weathering landforms in a cryotic environment, Northern Victoria Land, Antarctica
Authors: Guglielmin Mauro , Cannone Nicoletta , Strini Andrea , Lewkowicz Antoni G.
Published: March 2005

A multidisciplinary study was carried out to understand the interactions between biotic and abiotic processes in granite weathering in ice‐free areas of Northern Victoria Land, Antarctica. Examples of tafoni, pits and grooves were analyzed, focusing on their morphometry, infills, weathering rind types and vegetation patterns. Surface and subsurface temperatures and incoming radiation were measured to characterize microclimatic conditions. In addition, microscopic, SEM and X‐ray diffraction analyses of granite were carried out. These analyses indicate that, under present conditions, mechanical weathering is the main process active in the formation of tafoni, which post‐date pits and grooves. In these forms, granular disintegration is mainly induced by chasmoendolithic lichens, salt and thermal stress associated with the dilatation coefficients of different granite‐forming minerals. The overall morphology of pits and grooves indicates that they originate from water erosion. In the former, mechanical weathering prevails, caused by epilithic lichens, by freeze–thaw events, and by salt, while only the first two processes are active in the grooves. The intensity of these processes is less effective than in tafoni and on the outer surfaces, suggesting that pits and grooves are inherited features, possibly generated in the same way as landforms occurring on granite in the humid tropics. Copyright © 2005 John Wiley & Sons, Ltd.
Frequency and magnitude of active‐layer detachment failures in discontinuous and continuous permafrost, northern Canada
Authors: Lewkowicz Antoni G. , Harris Charles
Published: March 2005

Active‐layer detachment failures triggered weeks to months after forest fire in the central Mackenzie Valley (65°N, discontinuous permafrost zone) are compared to others generated almost immediately by summer meteorological conditions on the Fosheim Peninsula, Ellesmere Island (80°N, continuous permafrost zone). Preferred long‐axis orientations in both zones vary in relation to valley geometry and ground ice distribution: differential insolation plays no direct role in detachment failure distribution. Rates of geomorphic work over periods of one to two centuries are of the same order of magnitude. Threshold meteorological conditions for initiating failures on the Fosheim Peninsula can be incorporated into a surface heating index, but pre‐conditioning of the active layer remains important because rapid thaw does not always initiate activity. Slope pre‐conditioning does not occur at the fire‐affected sites because the failure zone is within formerly perennially frozen ground. Long‐term rates of unit vertical transport at the most active site on the Fosheim Peninsula are similar to those due to debris flow and slushflow in a nearby mountain range. The frequency of potential triggering events at the Ellesmere Island sites is expected to increase if summer climate warms, providing low percentage cloud cover is maintained during periods of high air temperatures. Copyright © 2005 John Wiley & Sons, Ltd.
Dissociation of dislocations and the mobility of partial dislocations in elemental semiconductors
Authors: Vanderschaeve G. , Caillard D.
Published: March 2005

From a theoretical analysis of the energy of dissociated dislocations moving in a periodic Peierls potential, it is shown that metastable dissociation configurations are expected, the range of which is asymmetrically distributed with respect to the equilibrium dissociation distance. In the course of this investigation, we have reexamined the literature data on the dissociation of dislocations in high‐stress deformed silicon. It is concluded that the experimental results can be interpreted in a consistent way without the assumption of different mobilities for leading or trailing partials. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improvement of crystalline quality of GaPN layers grown by RF‐plasma MBE with ion collector
Authors: Utsumi A. , Furukawa Y. , Yonezu H. , Yoshizumi Y. , Morita Y. , Wakahara A.
Published: March 2005

The effects on structural crystalline quality and luminescence properties of deflecting nitrogen (N) ions away from the substrate were investigated for GaPN layers grown on GaP substrates by RF‐plasma MBE. The GaPN layers were grown with and without use of an ion collector for N ions deflection. The Pendellösung fringes in the X‐ray diffraction spectrum were more distinct in samples grown with than without the ion collector. This result indicates that the structural and/or interface quality were improved by preventing ion‐induced damage. The sample grown with the ion collector indicated higher crystalline quality by the more linear excitation power dependence of photoluminescence intensity. On the other hand, the sample grown without the ion collector appears to contain a high concentration of non‐radiative recombination centers related to the ion‐induced damage. The ion‐induced damage cannot be completely healed by rapid thermal annealing. To summarize, eliminating ion exposure during growth improves the crystalline quality and radiative recombination properties of the GaPN layer. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Demonstration of a GaN‐spacer high electron mobility transistor with low alloy scattering
Authors: Palacios T. , Shen L. , Keller S. , Chakraborty A. , Heikman S. , Buttari D. , DenBaars S. P. , Mishra U. K.
Published: March 2005

A new kind of high electron mobility transistor (HEMT) based on a GaN‐spacer is reported. To confine the two‐dimensional electron gas in this AlGaN‐free HEMT, a GaN/ultrathin AlN/GaN pseudo‐hetero‐junction has been used. The effective conduction band discontinuity is given by the AlN polarization‐induced electric field. This new transistor shows a superior general performance than the standard HEMT due to a decrease in the alloy and real space transfer scattering, as well as lower ohmic contact resistance. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Prognostic Impact of CK‐20‐positive Cells in Peripheral Venous Blood of Patients with Gastrointestinal Carcinoma
Authors: Friederichs Jan , Gertler Ralf , Rosenberg Robert , Nahrig Jörg , Führer Katrin , Holzmann Bernhard , Dittler Hans‐Joachim , Dahm Michael , Thorban Stefan , Nekarda Hjalmar , Siewer Jörg Rüdiger
Published: March 2005

Despite curative tumor resection, about 30%–50% of patients with locally advanced gastrointestinal (GI) carcinoma develop tumor recurrence which may be caused by pre‐ or intraoperative tumor cell dissemination. We examined the combination of optimized density gradient centrifugation with a CK‐20 reverse transcriptase‐polymerase chain reaction to detect and quantify circulating tumor cells in peripheral blood. Peripheral venous blood (20 ml) of patients with GI carcinomas was collected during primary tumor staging before and after the endoscopy procedure. CK‐20 expression in peripheral venous blood was found in 22 of 82 patients (26.8%) with a nonsignificant difference between the upper GI tract (23.9%) and the lower GI tract (30.5%). The correlation with clinical outcome (24‐month‐survival) revealed a significantly worse prognosis (p < 0.05) of CK‐20–positive patients with carcinoma of the upper GI tract and a trend toward a worse prognosis for patients with carcinoma of the lower GI tract. Quantification of CK‐20 expression in peripheral blood showed a significantly higher circulating CK‐20 copy number (median: 2816) in patients with metastatic tumors than in those with non‐metastatic tumors (median: 983) (p < 0.05). For a subset of 42 primarily operated patients, we correlated the detection rate with UICC (International Union Against Cancer) staging categories. In contrast to the upper GI tract, the detection rate of patients with carcinoma of the lower GI tract showed a trend toward tumor size (pT) and a significant correlation with the presence of distant metastases (pM) (p < 0.01) and the postoperative residual tumor status (R) (p < 0.01). The endoscopy procedure did not lead to an increased detection of CK‐20 expression.
Hepatic Resection for Metastatic Breast Cancer: Prognostic Analysis of 34 Patients
Authors: Sakamoto Yoshihiro , Yamamoto Junji , Yoshimoto Masataka , Kasumi Fujio , Kosuge Tomoo , Kokudo Norihiro , Makuuchi Masatoshi
Published: March 2005

Liver metastasis of breast cancer is considered a generalized disease, and surgical treatment is rarely discussed. Thirty‐four patients who underwent 35 hepatectomies for liver metastases of breast cancer between 1985 and 2003 were analyzed. The median interval between the breast surgery and relapse in the liver was 1.9 years (0–20 years). The liver was the first site of recurrence in 25 patients. Fifteen clinicopathologic factors were evaluated using univariate and multivariate analyses to predict survival after hepatic resection. No patients died because of the surgery. The median survival was 36 months (1 month to 20 years). The overall and disease‐free 5‐year survival rates after hepatectomy for breast metastases were 21% and 16%, respectively. Four patients survived more than 5 years. The presence of extrahepatic recurrence prior to hepatectomy was the only significant prognostic factor according to the analyses, and the 5‐year survival rate of patients without extrahepatic disease was 31%. No patient who had hilar lymph node metastasis survived more than 5 years. In the absence of extrahepatic recurrence, surgical resection of liver metastasis from breast cancer can offer an acceptable prognosis and should not be avoided in selected patients.
The anticoagulant protein C pathway
Authors: Dahlbäck Björn , Villoutreix Bruno O
Published: March 2005

The anticoagulant protein C system regulates the activity of coagulation factors VIIIa and Va, cofactors in the activation of factor X and prothrombin, respectively. Protein C is activated on endothelium by the thrombin–thrombomodulin–EPCR (endothelial protein C receptor) complex. Activated protein C (APC)‐mediated cleavages of factors VIIIa and Va occur on negatively charged phospholipid membranes and involve protein cofactors, protein S and factor V. APC also has anti‐inflammatory and anti‐apoptotic activities that involve binding of APC to EPCR and cleavage of PAR‐1 (protease‐activated receptor‐1). Genetic defects affecting the protein C system are the most common risk factors of venous thrombosis. The protein C system contains multi‐domain proteins, the molecular recognition of which will be reviewed.
Age determination and growth of Atlantic redfish (Sebastes marinus and S. mentella): bias and precision of age readers and otolith preparation methods
Authors: Stransky Christoph , Gudmundsdóttir Sif , Sigurdsson Thorsteinn , Lemvig Svend , Nedreaas Kjell , Saborido-Rey Fran
Published: March 2005

Age determination of Atlantic redfish (Sebastes spp.) has proven difficult and has led to inconsistent age and growth estimates in the past. Using otoliths of the two major commercial species, golden redfish (Sebastes marinus) and deep-sea redfish (S. mentella), a series of exchange schemes was carried out to assess bias and precision of age readings between four readers and between two preparation methods. Considerable bias between readers and moderate precision were observed for the S. marinus readings, especially for ages >20 years, with coefficients of variation (CV) of 7.7–12.0% and average percent error (APE) of 5.4–8.5%. Agreement between readers increased from 17–28% to 45–61% when allowing deviations of ±1 year, and to 80–92% with ±3 years tolerance. The age of S. marinus determined from broken and burnt otoliths was estimated to be slightly lower than when the age of the same individuals was determined from thin-sectioned otoliths. The bias and precision estimates obtained from the S. mentella material were generally poorer than for S. marinus (CV 8.2–19.1%, APE 5.8–13.5%), but similar to reported values for other long-lived fish species. Better than 50% agreement was only achieved with ±3 years tolerance. Growth rates differed significantly between species, confirming slower growth for S. mentella. For S. marinus, only one reader comparison revealed significantly different growth functions, whereas almost all S. mentella reader pairs showed significant differences in growth curves. Section and break-and-burn readings of S. marinus did not differ significantly. Average ages of around 9–10 years were determined for juvenile S. mentella 24–30 cm long, which were likely to have migrated from East Greenland into the Irminger Sea, based on earlier observations. As some of the error in the age determinations presented could be attributed to interpretation differences between readers, further intercalibration of redfish ageing is urgently needed in order to provide consistent input data for stock assessment.
Development and validation of a measurement instrument for studying supply chain management practices
Authors: Li Suhong , Rao S. Subba , Ragu‐Nathan T.S. , Ragu‐Nathan Bhanu
Published: March 2005

It is widely argued that competition is no longer between organizations, but among supply chains. Effective supply chain management (SCM) has become a potentially valuable way of securing competitive advantage and improving organizational performance. This research conceptualizes, develops, and validates six dimensions of SCM practices (strategic supplier partnership, customer relationship, information sharing, information quality, internal lean practices, and postponement). Data for the study were collected from 196 organizations and the measurement scales were tested and validated using structural equation modeling. It is hoped that this study will provide a parsimonious measurement instrument to assess the performance of the overall supply chain.
Free radical scavenging alleviates the biomechanical impairment of gamma radiation sterilized bone tissue
Authors: Akkus Ozan , Belaney Ryan M. , Das Prasenjit
Published: March 2005

Terminal sterilization of bone allografts by gamma radiation is often essential prior to their clinical use to minimize the risk of infection and disease transmission. While gamma radiation has efficacy superior to other sterilization methods it also impairs the material properties of bone allografts, which may result in premature clinical failure of the allograft. The mechanisms by which gamma radiation sterilization damages bone tissue are not well known although there is evidence that the damage is induced via free radical attack on the collagen. In the light of the existing literature, it was hypothesized that gamma radiation induced biochemical damage to bone's collagen that can be reduced by scavenging for the free radicals generated during the ionizing radiation. It was also hypothesized that this lessening of the extent of biochemical degradation of collagen will be accompanied by alleviation in the extent of biomechanical impairment secondary to gamma radiation sterilization. Standardized tensile test specimens machined from human femoral cortical bone and specimens were assigned to four treatment groups: control, scavenger treated‐control, irradiated and scavenger treated‐irradiated. Thiourea was selected as the free radical scavenger and it was applied in aqueous form at the concentration of 1.5 M. Monotonic and cyclic mechanical tests were conducted to evaluate the mechanical performance of the treatment groups and the biochemical integrity of collagen molecules were assessed by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis.

The native mechanical properties of bone tissue did not change by thiourea treatment only. The effect of thiourea treatment on mechanical properties of irradiated specimens were such that the post‐yield energy, the fracture energy and the fatigue life of thiourea treated‐irradiated treatment group were 1.9‐fold, 3.3‐fold and 4.7‐fold greater than those of the irradiated treatment group, respectively. However, the mechanical function of thiourea treated and irradiated specimens was not to the level of unirradiated controls. The damage occurred through the cleavage of the collagen backbone as revealed by SDS PAGE analysis. Irradiated specimens did not exhibit a noteworthy amount of intact α‐chains whereas those irradiated in the presence of thiourea demonstrated intact α‐chains. Results demonstrated that free radical damage is an important pathway of damage, caused by cleaving the collagen backbone. Blocking the activity of free radicals using the scavenger thiourea reduces the extent of damage to collagen, helping to maintain the mechanical strength of sterilized tissue. Therefore, free radical scavenger thiourea has the potential to improve the functional life‐time of the allograft component following transplantation. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
The effect of ankle ligament damage and surgical reconstructions on the mechanics of the ankle and subtalar joints revealed by three‐dimensional stress MRI
Authors: Ringleb S. I. , Udupa J. K. , Siegler S. , Imhauser C. W. , Hirsch B. E. , Liu J. , Odhner D. , Okereke E. , Roach N.
Published: March 2005

Common image‐based diagnostic techniques used to detect ankle ligament injuries or the effects of those injuries (e.g. mechanical instability) include magnetic resonance imaging (MRI) and stress radiography. Each of these techniques has limitations. The interpretation of the results obtained through stress radiography, a two‐dimensional technique, is highly controversial. MRI can facilitate visualization of soft tissue, but three‐dimensional visualization of the full length of the ligaments or detecting partial ligament damage is difficult. This work is part of a long‐term study aimed at improving the diagnostic ability of MRI by utilizing it not only to visualize the ligaments but also to detect the mechanical instability produced at the ankle and subtalar joints due to ligament damage. The goal of the present study was to evaluate the ability of a previously developed technique called 3D stress MRI (sMRI) to detect in vitro the effect of damage to the lateral collateral ligaments and the stabilizing effect produced by two common surgical reconstruction techniques. MRI data were collected from eight cadaver limbs in a MR compatible ankle‐loading device in neutral, inversion, and anterior drawer. Each specimen was tested intact, after cutting the anterior talo‐fibular ligament followed by the calcaneo‐fibular ligament and after applying two reconstructions. Ligament injuries produced significant changes in the response of the ankle and subtalar joints to load as detected by the 3D stress MRI technique. Both surgical procedures restored mechanical stability to the joints but they differed in the amount and type of stabilization achieved. We concluded that 3D sMRI can extend the diagnostic power of MRI from the current practice of slice‐by‐slice visualization to the assessment of mechanical function, the compromise in this function due to injury, and the effects of surgery. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Introduction: historical geographies of science – places, contexts, cartographies
Authors: NAYLOR SIMON
Published: March 2005

This paper outlines the contours of a historical geography of science. It begins by arguing for the relevance of spatially oriented histories of scientific thought and practice. The paper then considers three different historical geographies of science: those concerned with the places and spaces of science, those that detail the spatial contexts of scientific endeavour, and those that analyse the internal ‘cartographies’ of scientific theories and methods. The paper concludes with a discussion of other possible avenues of investigation in this field.

Scientific knowledge is made in a lot of different places. Does it matter where? Can the location of scientific endeavour make any difference to the conduct of science? And even more important, can it affect the content of science? In my view the answer to these questions is yes.
Mapping science's imagined community: geography as a Republic of Letters, 1600–1800
Authors: MAYHEW ROBERT
Published: March 2005

This paper extends discussions of the sociology of the early modern scientific community by paying particular attention to the geography of that community. The paper approaches the issue in terms of the scientific community's self image as a Republic of Letters. Detailed analysis of patterns of citation in two British geography books is used to map the ‘imagined community’ of geographers from the late Renaissance to the age of Enlightenment. What were the geographical origins of authors cited in geography books and how did this change over time? To what extent was scholarship from other cultural arenas integrated into European geography? Such an analysis draws on and interrogates recent work in the history of science and in the history of scholarship more broadly, work which has made important contributions to our understanding of the historical geography of scholarly communities in early modern Europe.
The Abolition of Compulsory Church Parades in the British Army
Authors: CRANG JEREMY A.
Published: March 2005

The compulsory church parade was one of the oldest traditions in the British army, dating back to the seventeenth century. In 1946, shortly after the end of the Second World War, the practice was abolished. This was a significant moment in Army–Church relations since the compulsory attendance of soldiers at divine worship had been an official acknowledgement of the importance of religion as a guiding force in the corporate life of the army. This article explores the background to this historic decision and the unsuccessful efforts of senior officers in the late 1940s to restore the ritual.
The English Reformation: Obedience, Destruction and Cultural Adaptation
Authors: FRITZE RONALD H.
Published: March 2005

Religious life and English culture in the Reformation. By Marjo Kaartinen. Pp. vii+210. Basingstoke: Palgrave, 2002. £45. ISBN 0 333 96924 3

Preaching during the English Reformation. By Susan Wabuda. Pp. xx+203 incl. 15 figs. Cambridge: Cambridge University Press, 2002. £40. ISBN 0 521 45395 X

Authority and consent in Tudor England. Essays presented to C. S. L. Davies. Edited by G. W. Bernard and S. J. Gunn. Pp. x+301. Aldershot: Ashgate Publishing Ltd, 2002. £47.50. ISBN 0 7546 0665 1

Keywords and concepts provide important organising principles when historians attempt to make sense of the past. Some keywords are virtual constants of historical discourse, such as ‘continuity’ and ‘change’, although the relative emphasis that historians place on them can fluctuate with circumstances and fashion. Other terms come and go. The study of the English Reformation is no exception to the ebb and flow of historical keywords. For much of the 1960s, 1970s and the early 1980s, ‘popular reformation’ was a central concept of interpretation and research. But no more. Thanks to the historical fashion which has been styled ‘revisionism’, ‘popular reformation’ in early sixteenth-century England at least is widely considered to be an oxymoron. Consequent on the work of A. G. Dickens, ‘official’ or ‘state-sponsored reformation’ went into an eclipse but with the advent of revisionism it has been both revived as well as revised.