bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glacier variations in Breheimen, southern Norway: dating Little Ice Age moraine sequences at seven low‐altitude glaciers
Authors: Winkler Stefan , Matthews John A. , Shakesby Richard A. , Dresser P. Quentin 
Published: June 2003

AbstractMoraine sequences in front of seven relatively low‐altitude glaciers in the Breheimen region of central southern Norway are described and dated using a ‘multi‐proxy’ approach to moraine stratigraphy. Lichenometric dating, based on theRhizocarponsubgenus, is used to construct a composite moraine chronology, which indicates eight phases of synchronous moraine formation:AD1793–1799, 1807–1813, 1845–1852, 1859–1862, 1879–1885, 1897–1898, 1906–1908 and 1931–1933. Although the existence of a few cases of older moraines, possibly dating from earlier in the eighteenth or late in the seventeenth centuries cannot be ruled out by lichenometry, Schmidt hammer R‐values from boulders on outermost moraine ridges suggest an absence of Holocene moraines older than the Little Ice Age. Twenty‐three radiocarbon dates from buried soils and peat associated with outermost moraines at three glaciers—Tverreggibreen, Storegrovbreen and Greinbreen—also indicate that the ‘Little Ice Age’ glacier maximum was the Neoglacial maximum at most if not all glaciers. Severalmaximumage estimates for the Little Ice Age glacier maximum range between the fifteenth and seventeenth centuries, with the youngest from a buried soil beingAD1693. A pre‐Little Ice Age maximum cannot be ruled out at Greinbreen, however, where the age of buried peat suggests the outermost moraine dates fromAD981–1399 (at variance with the lichenometric evidence). Glaciofluvial stratigraphy at Tverreggibreen provides evidence for minor glacier advances aboutAD655–963 andAD1277–1396, respectively. Copyright © 2003 John Wiley & Sons, Ltd.
Palaeotemperature reconstructions of the European permafrost zone during marine oxygen isotope Stage 3 compared with climate model results
Authors: van Huissteden Ko , Vandenberghe Jef , Pollard David 
Published: June 2003

AbstractA palaeotemperature reconstruction based on periglacial phenomena in Europe north of approximately 51 °N, is compared with high‐resolution regional climate model simulations of the marine oxygen isotope Stage 3 (Stage 3) palaeoclimate. The experiments represent Stage 3 warm (interstadial), Stage 3 cold (stadial) and Last Glacial Maximum climatic conditions. The palaeotemperature reconstruction deviates considerably for the Stage 3 cold climate experiments, with mismatches up to 11 °C for the mean annual air temperature and up to 15 °C for the winter temperature. However, in this reconstruction various factors linking climate and permafrost have not been taken into account. In particular a relatively thin snow cover and high climatic variability of the glacial climate could have influenced temperature limits for ice‐wedge growth. Based on modelling the 0 °C mean annual ground temperature proves to be an appropriate upper temperature limit. Using this limit, mismatches with the Stage 3 cold climate experiments have been reduced but still remain. We therefore assume that the Stage 3 ice wedges were generated during short (decadal time‐scale) intervals of extreme cold climate, below the mean temperatures indicated by the Stage 3 cold climate model simulations. Copyright © 2003 John Wiley & Sons, Ltd.
Systematic regulation of spine sizes and densities in pyramidal neurons
Authors: Konur Sıla , Rabinowitz Daniel , Fenstermaker Vivian L. , Yuste Rafael 
Published: June 2003

AbstractDendritic spines receive most excitatory inputs in the CNS. Recent evidence has demonstrated that the spine head volume is linearly correlated with the readily releasable pool of neurotransmitter and the PSD size. These correlations can be used to functionally interpret spine morphology. Using Golgi impregnations and light microscopy, we reconstructed 23,000 spines from pyramidal neurons in layers 2/3, 4, 5 and 6 of mouse primary visual cortex and CA1 hippocampal region and measured their spine head diameters and densities. Spine head diameters and densities are variable within and across cells, although they are similar between apical and basal dendrites. When compared to other regions, layer 5 neurons have larger spine heads and CA1 neurons higher spine densities. Interestingly, we detect a correlation between spine head diameter and interspine distance within and across cells, whereby larger spines are spaced further away from each other than smaller spines. Finally, in CA1 neurons, spine head diameters are larger, and spine density lower, in distal apical dendrites (>200 μm from soma) compared to proximal regions. These results reveal that spine morphologies and densities, and therefore synaptic properties, are jointly modulated with respect to cortical region, laminar position, and, in some cases, even the position of the spine along the dendritic tree. Individual neurons also appear to regulate their apical and basal spine densities and morphologies in concert. Our data provide evidence for a homeostatic control of excitatory synaptic strength. © 2003 Wiley Periodicals, Inc. J Neurobiol 56: 95–112, 2003
A composite transformation for numerical integration of singular integrals in the BEM
Authors: Yun Beong In 
Published: June 2003

AbstractIn this paper we present a composite non‐linear transformation of a polynomial transformation (PT) and a sigmoidal transformation (ST) by the name of CT_PS (composite transformation with polynomial and sigmoidal transformations). This new transformation can be used for both Cauchy principal value (CPV) integrals and weakly singular integrals with interior singularities. Moreover, it is implied that the numerical evaluation using CT_PS would be more efficient than either PT or ST used alone. By numerical examples, we show that the presented CT_PS method, with the Gauss–Legendre quadrature rule, improves the approximation errors of the existing methods effectively. In particular, it is demonstrated that the results of the present method are excellent for CPV integrals with near end point singularities. Copyright © 2003 John Wiley & Sons, Ltd.
Determination of amplicon boundaries at 20q13.2 in tissue samples of human gastric adenocarcinomas by high‐resolution microarray comparative genomic hybridization
Authors: Weiss Marjan M , Snijders Antoine M , Kuipers Ernst J , Ylstra Bauke , Pinkel Daniel , Meuwissen Stefan GM , van Diest Paul J , Albertson Donna G , Meijer Gerrit A 
Published: July 2003

AbstractComparative genomic hybridization (CGH) of gastric adenocarcinomas frequently shows gains and amplifications of chromosome 20. However, the underlying genetic lesion is unknown and conventional CGH results do not allow specification of the target region. In order to investigate this chromosomal aberration with a higher resolution and sensitivity, microarray‐based CGH was performed with both scanning and high‐resolution arrays of chromosome 20 in a series of 27 gastric adenocarcinomas. Locus‐specific fragments of genomic DNA from bacterial artificial chromosome (BAC) clones were spotted as microarrays. A scanning array contained a set of 27 BAC clones covering chromosome 20q. A high‐resolution array contained 27 overlapping BAC clones at 20q13.2. This high‐resolution array was used to narrow down the amplicon at 20q13.2 in tumours showing amplification of this chromosomal region with the scanning array. Positive copy number changes on chromosome 20q were detected in 12 of 27 cases (44%). These changes included gain of the whole arm of chromosome 20q in 8 of 27 (30%) cases, amplification restricted to 20q12.1 in one case, and amplifications restricted to 20q13 in three cases (11%). The three tumours showing amplification restricted to 20q13 were analysed further using the high‐resolution array. In one tumour, the whole contig was amplified at a constant level. One of the other two tumours had a clear proximal breakpoint, while the other tumour had a clear distal breakpoint within the 20q13.2 region. The proximal and the distal breakpoint were approximately 800 kb apart. In the present study, an amplicon at 20q13.2 has been narrowed down to 800 kb which is likely to harbour one or more putative oncogenes relevant to gastric carcinogenesis, for which ZNF217 and CYP24 are good candidates. Copyright © 2003 John Wiley & Sons, Ltd.
Expression of TRAIL (TNF‐related apoptosis‐inducing ligand) and its receptors in normal colonic mucosa, adenomas, and carcinomas
Authors: Koornstra Jan J , Kleibeuker Jan H , van Geelen Caroline MM , Rijcken Fleur EM , Hollema Harry , de Vries Elisabeth GE , de Jong Steven 
Published: July 2003

AbstractTumour necrosis factor‐related apoptosis‐inducing ligand (TRAIL) induces apoptosis in tumour cell lines. Four membrane‐bound receptors for TRAIL have been identified, two apoptosis‐mediating receptors, DR4 and DR5, and two apoptosis‐inhibiting receptors, DcR1 and DcR2. The aim of this study was to examine the role of TRAIL and its receptors in colorectal cancer development. The immunohistochemical expression and localization of TRAIL and its receptors were investigated in normal mucosa (n = 10), adenomas (n = 19), and carcinomas (n = 21). Correlations between the expression of TRAIL and its receptors and the degree of apoptosis (assessed by M30 expression) and histopathological characteristics were explored. TRAIL and its receptors were expressed in normal mucosal epithelium. Expression of the receptors was seen in adenomas and carcinomas. TRAIL expression was lost in a subset of colorectal tumours, more frequently in carcinomas than in adenomas (p < 0.05). DR4 and DR5 staining was stronger in neoplastic cells than in normal cells and was accompanied by a higher degree of apoptosis. No differences were found between tumour and normal cells regarding DcR1 and DcR2 expression. No correlations were found between TRAIL or TRAIL receptor expression and histopathological characteristics. In conclusion, marked changes were seen in the course of the adenoma–carcinoma sequence with respect to the expression of TRAIL and TRAIL receptors DR4 and DR5. The stronger expression of DR4 and DR5 in neoplastic cells than in normal cells, together with a higher degree of apoptosis, suggests a possible functional role for these receptors in apoptosis induction in neoplastic colorectal cells. Copyright © 2003 John Wiley & Sons, Ltd.
Expression of VEGF, semaphorin SEMA3F, and their common receptors neuropilins NP1 and NP2 in preinvasive bronchial lesions, lung tumours, and cell lines
Authors: Lantuéjoul Sylvie , Constantin Bruno , Drabkin Harry , Brambilla Christian , Roche Joëlle , Brambilla Elisabeth 
Published: July 2003

AbstractTwo receptors, neuropilin 1 (NP1) and neuropilin 2 (NP2), bind class 3 semaphorins, axon guidance molecules including SEMA3F, the gene for which was isolated from a 3p21.3 deletion in lung cancer. In addition, they bind VEGF (vascular endothelial growth factor), enhancing the effects of VEGF binding to KDR/Flk‐1. Elevated VEGF levels are associated with the loss and cytoplasmic delocalization of SEMA3F in lung cancer, suggesting competition for their NP1 and NP2 receptors. To determine the timing of these events, we compared by immunohistochemistry VEGF, SEMA3F, NP1 and NP2 expression in 50 preneoplastic lesions and 112 lung tumours. In preneoplastic lesions, VEGF increased from low‐grade to high‐grade dysplasia (p = 0.001) whereas SEMA3F levels remained low. NP1 and NP2 levels increased from dysplasia to microinvasive carcinoma (p = 0.0001) and correlated with VEGF expression (p = 0.04 and 0.0002, respectively). Non‐small cell lung carcinoma overexpressed VEGF and NP1 and NP2 significantly more often than neuroendocrine tumours including small cell lung carcinoma. SEMA3F loss or delocalization correlated with advanced tumour stage. Migrating cells overexpressed VEGF, SEMA3F, NP1 and NP2 with cytoplasmic delocalization of NP1 as demonstrated in an in vitro wound assay. These results demonstrate early alteration of the VEGF/SEMA3F/NP pathway in lung cancer progression. Copyright © 2003 John Wiley & Sons, Ltd.
Expression of the HER1–4 family of receptor tyrosine kinases in breast cancer
Authors: Witton Caroline J , Reeves Jonathan R , Going James J , Cooke Timothy G , Bartlett John MS 
Published: July 2003

AbstractEGFr/HER1 and c‐erbB‐2/HER2 expression are associated with poor prognosis in breast cancer. The type I receptor tyrosine kinase (RTK) family to which they belong has four members (HER1–4). In this study, expression of HER1–4 and oestrogen receptor (ER) expression were determined by immunohistochemistry in 220 breast carcinomas. Elevated expression of HER1 was observed in 16.4%, HER2 in 22.8%, HER3 in 17.5%, and HER4 in 11.9% of these tumours. Patients whose tumours overexpressed HER1, 2 or 3 had reduced survival (p = <0.001), whereas those whose tumours overexpressed HER4 had increased survival (p = 0.013); 38.6% of cases overexpressed one or more of HER1, 2 or 3. HER4 was rarely overexpressed with other HERs (1.4% of cases). Cox's multiple regression analysis demonstrated that overexpression of HER1/2/3, HER4, and standard prognostic indicators independently affected survival. HER1–3 expression was related to ER negativity (p < 0.0001, χ2). Patients with ER‐positive, HER1–3‐positive tumours had a significantly poorer survival (p < 0.001) than those with ER‐positive/HER‐negative or HER4‐positive tumours. Expression of HER RTKs displays complex interactions between different family members. There is a strong interaction, in terms of survival, between HER expression and ER expression. The development of HER‐targeted agents (eg Herceptin, Iressa), and agents targeted at the downstream signalling pathways, therefore provides new possibilities in the treatment of breast cancer. Copyright © 2003 John Wiley & Sons, Ltd.
The dynamic extracellular matrix: intervention strategies during heart failure and atherosclerosis
Authors: Heeneman Sylvia , Cleutjens Jack P , Faber Birgit C , Creemers Esther E , van Suylen Robert‐Jan , Lutgens Esther , Cleutjens Kitty B , Daemen Mat J 
Published: July 2003

AbstractThe extracellular matrix is no longer seen as the static embedding in which cells reside; it has been shown to be involved in cell proliferation, migration and cell–cell interactions. Turnover of the different extracellular matrix components is an active process with multiple levels of regulation. Collagen, a major extracellular matrix constituent of the myocardium and the arterial vascular wall, is synthesized by (myo)fibroblasts in the myocardium and smooth muscle cells in the medial arterial vascular wall. Its degradation is controlled by proteinases, which include matrix metalloproteinases. This review will focus on the impact of fibrosis and especially collagen turnover on the progression of heart failure and atherosclerosis, two of the main cardiovascular pathologies. We will discuss data from human studies and animal models, with an emphasis on the effects of interventions on collagen synthesis and degradation. We conclude that there is a dynamic (dis)balance in the rate of collagen synthesis and degradation during heart failure and atherosclerosis, which makes the outcome of interventions not always predictable. Alternative approaches for intervening in collagen metabolism will be discussed as possible therapeutic intervention strategies. Copyright © 2003 John Wiley & Sons, Ltd.
Role of tissue stroma in cancer cell invasion
Authors: De Wever Olivier , Mareel Marc 
Published: July 2003

AbstractMaintenance of epithelial tissues needs the stroma. When the epithelium changes, the stroma inevitably follows. In cancer, changes in the stroma drive invasion and metastasis, the hallmarks of malignancy. Stromal changes at the invasion front include the appearance of myofibroblasts, cells sharing characteristics with fibroblasts and smooth muscle cells. The main precursors of myofibroblasts are fibroblasts. The transdifferentiation of fibroblasts into myofibroblasts is modulated by cancer cell‐derived cytokines, such as transforming growth factor‐β (TGF‐β). TGF‐β causes cancer progression through paracrine and autocrine effects. Paracrine effects of TGF‐β implicate stimulation of angiogenesis, escape from immunosurveillance and recruitment of myofibroblasts. Autocrine effects of TGF‐β in cancer cells with a functional TGF‐β receptor complex may be caused by a convergence between TGF‐β signalling and β‐catenin or activating Ras mutations. Experimental and clinical observations indicate that myofibroblasts produce pro‐invasive signals. Such signals may also be implicated in cancer pain. N‐Cadherin and its soluble form act as invasion‐promoters. N‐Cadherin is expressed in invasive cancer cells and in host cells such as myofibroblasts, neurons, smooth muscle cells, and endothelial cells. N‐Cadherin‐dependent heterotypic contacts may promote matrix invasion, perineural invasion, muscular invasion, and transendothelial migration; the extracellular, the juxtamembrane and the β‐catenin binding domain of N‐cadherin are implicated in positive invasion signalling pathways. A better understanding of stromal contributions to cancer progression will likely increase our awareness of the importance of the combinatorial signals that support and promote growth, dedifferentiation, invasion, and ectopic survival and eventually result in the identification of new therapeutics targeting the stroma. Copyright © 2003 John Wiley & Sons, Ltd.
Tenascins: regulation and putative functions during pathological stress
Authors: Chiquet‐Ehrismann Ruth , Chiquet Matthias 
Published: July 2003

AbstractIn this review, we discuss the structure and function of the extracellular matrix protein family of tenascins with emphasis on their involvement in human pathologies. The article is divided into the following sections: Introduction: the tenascin family of extracellular matrix proteins; Structural roles: tenascin‐X deficiency and Ehlers–Danlos syndrome; Tenascins as modulators of cell adhesion, migration, and growth; Role of tenascin‐C in inflammation; Regulation of tenascins by mechanical stress: implications for wound healing and regeneration; Association of tenascin‐C with cancer: antibodies as diagnostic and therapeutic tools; Conclusion and perspectives. Copyright © 2003 John Wiley & Sons, Ltd.
Das ideale Quantenlabor: Bose‐Einstein‐Kondensation
Authors: Sengstock Klaus , Bongs Kai , Reichel Jakob 
Published: June 2003

AbstractBose‐Einstein‐Kondensate (BEC) sind extrem kalte Gase aus bosonischen Atomen, die sich alle im energetischen Grundzustand versammeln. Ein BEC ist ein perfektes Quantenlabor. Es bietet eine makroskopische Materiewelle aus vielen Tausend Teilchen an, die dem Experiment offen zugänglich ist. Das unterscheidet es von anderen makroskopischen Quantenzuständen wie der Suprafluidität oder der Supraleitung, denn diese verbergen sich in Flüssigkeiten oder Festkörpern. Das BEC ist also ein ideales Modellsystem, um diese und andere Phänomene der Quantenmechanik zu studieren. Neue Perspektiven eröffnet die schnelle Erzeugung und leichte Manipulation eines Kondensats auf einem Mikrochip. Dazu gehören auch vielfältige Anwendungen bis hin zum Quantencomputer.
Erstmalige Spektroskopie des Elements Fermium
Authors: Backe Hartmut , Sewtz Michael 
Published: June 2003

AbstractDas Element Fermium (Z=100) wurde 1952 in den Überresten einer thermonuklearen Explosion entdeckt. Es ist das schwerste Element, das über sukzessiven Neutroneneinfang und Betazerfall hergestellt werden kann. Jetzt ließ sich erstmals die atomare Struktur spektroskopisch studieren. Dafür wurde eine 2 ng leichte Probe von 255Fm (Halbwertszeit 20,1 Stunden) am Hochfluss‐Kernreaktor des Oak Ridge National Laboratory, USA, produziert und nach Deutschland versandt [1].
A fully automated nanoelectrospray tandem mass spectrometric method for analysis of Caco‐2 samples
Authors: Van Pelt Colleen K. , Zhang Sheng , Fung Eliza , Chu Inhou , Liu Tongtong , Li Cheng , Korfmacher Walter A. , Henion Jack 
Published: July 2003

AbstractCaco‐2 cells offer a means to rapidly screen permeability of drug candidates, allowing pharmaceutical companies to eliminate candidates unable to cross the intestinal barrier early in the discovery process. This screening process is typically performed by conventional liquid chromatography/tandem mass spectrometry (LC/MS/MS), which can require time‐consuming method development. An alternative to LC/MS/MS, automated nanoelectrospray tandem mass spectrometry (nanoESI‐MS/MS), is introduced. This novel approach requires an off‐line ZipTip™ desalting step followed by automated nanoESI‐MS/MS, using the NanoMate™ 100 and ESI Chip™. In addition to reduced method development time, automated nanoESI‐MS/MS also offers no carry‐over between samples, low sample consumption, and ease‐of‐use as compared with conventional pulled‐capillary nanoelectrospray. Furthermore, the infusion system described has the potential to be high‐throughput. A comparison of Caco‐2 samples analyzed both by LC/MS/MS and by automated nanoESI‐MS/MS is presented. The permeability and recovery data of the two compounds analyzed in this study obtained from conventional LC/MS/MS and by automated nanoESI‐MS/MS were in excellent agreement. Copyright © 2003 John Wiley & Sons, Ltd.
Automated protein identification using atmospheric‐pressure matrix‐assisted laser desorption/ionization
Authors: Mehl John T. , Cummings John J. , Rohde Ellen , Yates Nathan N. 
Published: July 2003

AbstractAtmospheric‐pressure matrix‐assisted laser desorption/ionization (AP‐MALDI) ion trap mass spectrometry (ITMS) has been evaluated for automated protein identification. By using signal averaging and long ion‐injection times, protein identification limits in the 50‐fmol range are achieved for standard protein digests. Data acquisition requires 7.5 min or less per sample and the MS/MS spectra files are automatically processed using the SEQUEST database searching algorithm. AP‐MALDI‐ITMS was compared with the widely used methods of μLC/MS/MS (ion trap) and automated MALDI‐TOF peptide mass mapping. Sample throughput is 10‐fold greater using AP‐MALDI compared with microcapillary liquid chromatography/tandem mass spectrometry (μLC/MS/MS). The protein sequence coverage obtained from AP‐MALDI‐MS/MS spectra matched by SEQUEST is lower compared with μLC/MS/MS and MALDI‐TOF mass mapping. However, by using the AP‐MALDI full‐scan peptide mass fingerprint spectrum, sequence coverage is increased. AP‐MALDI‐ITMS was applied for the analysis of Coomassie blue stained gels and was found to be a useful platform for rapid protein identification. Copyright © 2003 John Wiley & Sons, Ltd.