bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics in Cold Laval Nozzle Expansions: From Atmospheric Chemistry to Oxidation of Biomolecules in the Gas Phase
Authors: Hansmann Björn , Abel Bernd 
Published: February 2007

AbstractNew developments and recent applications of pulsed and miniaturised Laval nozzle technology allowing many gas‐phase molecular processes to be studied at very low temperatures are highlighted. In the present Minireview we focus on molecular energy transfer and reactions of molecular radicals (e.g. OH) with neutral molecules. We show that with the combination of pulsed laser photolysis and sensitive laser‐induced fluorescence detection a large number of fast reactions of radicals with more or less complex neutral molecules can be measured in Laval nozzle expansions nowadays. It is also demonstrated that collisional energy transfer of neutral molecules can be measured via kinetically controlled selective fluorescence (KCSF) excitation down to 58 Kelvin. Finally, we show that even the primary steps in the oxidation of biomolecules or biomolecular building blocks initiated by OH radicals can be followed at low temperatures. The temperature dependence of the measured rate constants is the key for an understanding of the underlying molecular mechanisms and the Laval nozzle expansion provides a unique environment for these measurements. The experimental finding that many reactions between radicals and neutral species can be rapid at low temperatures are discussed in terms of pre‐reactive complexes formed in the overall complex forming bimolecular reactions.
Comparison of Thermodynamic Properties of Coarse‐Grained and Atomic‐Level Simulation Models
Authors: Baron Riccardo , Trzesniak Daniel , de Vries Alex H. , Elsener Andreas , Marrink Siewert J. , van Gunsteren Wilfred F. 
Published: February 2007

AbstractThermodynamic data are often used to calibrate or test atomic‐level (AL) force fields for molecular dynamics (MD) simulations. In contrast, the majority of coarse‐grained (CG) force fields do not rely extensively on thermodynamic quantities. Recently, a CG force field for lipids, hydrocarbons, ions, and water,1 in which approximately four non‐hydrogen atoms are mapped onto one interaction site, has been proposed and applied to study various aspects of lipid systems. To date, no extensive investigation of its capability to describe solvation thermodynamics has been undertaken. In the present study, a detailed picture of vaporization, solvation, and phase‐partitioning thermodynamics for liquid hydrocarbons and water was obtained at CG and AL resolutions, in order to compare the two types of models and evaluate their ability to describe thermodynamic properties in the temperature range between 263 and 343 K. Both CG and AL models capture the experimental dependence of the thermodynamic properties on the temperature, albeit a systematically weaker dependence is found for the CG model. Moreover, deviations are found for solvation thermodynamics and for the corresponding enthalpy–entropy compensation for the CG model. Particularly water/oil repulsion seems to be overestimated. However, the results suggest that the thermodynamic properties considered should be reproducible by a CG model provided it is reparametrized on the basis of these liquid‐phase properties.
Geomorphic evolution of small river–lake‐systems in northeast Germany during the Late Quaternary
Authors: Kaiser Knut , Rother Henrik , Lorenz Sebastian , Gärtner Peter , Papenroth Ralf 
Published: February 2007

AbstractThis study investigates the post‐glacial development of four small river–lake systems in the Weichselian belt of northern central Europe. The valleys investigated are part of an immature drainage system characterized by frequent and abrupt changes in flow direction and the presence of numerous stagnant‐ice depressions in the valley course. The depressions contain thick sedimentary sequences which provide excellent archives for the reconstruction of the post‐glacial valley development. Study results indicate that the valleys reuse segments of former subglacial meltwater channels. During the Late Pleniglacial these channels carried meltwater streams. Stagnant‐ice melting occurred in stages from the Oldest Dryas to the early Holocene and was often followed by the formation of lakes in the valley course. Flow reversals occurred during the Late‐glacial–Holocene transition and were in response to general base‐level lowering caused by stagnant‐ice melting, headwater erosion and lake overspills. Lacustrine deposition typically started during the early Late‐glacial comprising mainly silicate gyttjas, whereas organic gyttjas and peats accumulated during the Allerød. The Younger Dryas is associated with a marked increase in fluvial and aeolian sedimentation, and lake‐level high stands. This was followed by early Holocene lake‐level low stands and a subsequent stabilization phase with decreasing silicate input and increasing organic lacustrine deposition. In general, dramatic changes in Late Pleniglacial to early Holocene sedimentation suggest that small‐scale catastrophic events played a more important role in triggering geomorphic changes then previously recognized. Infilling continued until peat accumulation and terrestrialization of lake basins became widespread during the mid‐ to late Holocene. Beginning in the late Holocene anthropogenic influences become important mainly involving an increase in sediment supply due to forest clearing and land use, followed by mill stowage, river course correction and anthropogenic lake‐level manipulations. Copyright © 2007 John Wiley & Sons, Ltd.
Mountain permafrost dynamics within a recently exposed glacier forefield inferred by a combined geomorphological, geophysical and photogrammetrical approach
Authors: Kneisel C. , Kääb A. 
Published: February 2007

AbstractGeomorphological observations, geoelectrical soundings and photogrammetric measurements of surface movement on the Muragl glacier forefield were used to obtain an integrative analysis of a highly complex glacial and periglacial landform consisting of a push moraine, creeping permafrost and permafrost‐free glacial till in close proximity. Electrical resistivity tomography is considered as an important multifunctional geophysical method for research in periglacial permafrost related environments. Joint application with measurements of surface displacements offers a promising tool for investigating periglacial landforms related to ice‐rich permafrost for a more comprehensive characterization of permafrost characteristics and geomorphological interpretation of periglacial morphodynamics. The patchy permafrost distribution pattern described in this paper is determined by several factors, including the sediment characteristics, the snow cover distribution and duration, the aspect and the former glacier distribution and thermal regime. Recent and modern permafrost dynamics within the glacier forefield comprise aggradation, degradation and permafrost creep. Copyright © 2007 John Wiley & Sons, Ltd.
Tyrosine depletion alters cortical and limbic blood flow but does not modulate spatial working memory performance or task‐related blood flow in humans
Authors: Ellis Kathryn A. , Mehta Mitul A. , Naga Venkatesha Murthy P.J. , McTavish Sarah F.B. , Nathan Pradeep J. , Grasby Paul M. 
Published: February 2007

AbstractDopamine appears critical in regulating spatial working memory (SWM) within the PFC of non‐human primates; however findings in humans are less clear. Recent studies of the effects of global depletion of dopamine via acute tyrosine/phenylalanine depletion (TPD) on SWM task performance have yielded inconsistent results, which may be partly related to task differences. These previous studies do not address whether TPD can directly impair PFC functioning. The current study investigated the effects of TPD on (1) regional cerebral blood flow (rCBF) during a SWM n‐back task using H215O Positron Emission Tomography (PET), and (2) behavioural performance on three different SWM tasks. Ten healthy males were scanned twice: once following a placebo (balanced) amino acid mixture and once following an equivalent mixture deficient in tyrosine/phenylalanine (TPD condition). Participants completed two additional delayed‐response tasks to examine whether differences in response demands influenced TPD effects on performance. TPD resulted in widespread increases in rCBF, with maximum increases in the region of the parahippocampal gyrus bilaterally, left inferior frontal gyrus, and the putamen. TPD related rCBF reductions were observed in the medial frontal gyrus bilaterally, right inferior temporal gyrus and the pons. Despite widespread changes in blood flow following TPD, no specific effects on SWM neural networks or task performance were observed. The use of three different SWM tasks suggests that task differences are unlikely to account for the lack of effects observed. These findings question the capacity of TPD to consistently modulate dopamine function and SWM neural networks in humans. Hum Brain Mapp 2007. © 2007 Wiley‐Liss, Inc.
Whole brain analysis of T2* weighted baseline FMRI signal in dementia
Authors: Rombouts Serge A.R.B. , Scheltens Philip , Kuijer Joost P.A. , Barkhof Frederik 
Published: February 2007

AbstractBrain activation in studies using blood oxygenation level dependent (BOLD) FMRI is associated with an increase in T2* weighted signal between baseline and an active condition. This BOLD technique is often applied to study differences in brain activation between patients and healthy controls. However, the baseline T2* signal itself may also be different between groups, as shown in the hippocampus in Alzheimer's disease using the resting oxygen or ROXY approach (Small et al. [2002]: Ann Neurol 51:290–295). In the current study, we analyzed whole brain, voxel‐wise T2* weighted signal of averaged baseline scans of a BOLD FMRI experiment in 41 healthy elderly controls and 46 patients with mild cognitive impairment or Alzheimer's disease. In each subject, T2* weighted images were normalized to the CSF signal of the same image. Additionally, gray matter probability maps of high‐resolution structural scans were also compared between groups to assess atrophy. T2* signal was decreased in dementia in the hippocampus, insula/putamen, posterior and middle cingulate cortex, and parietal cortex. Most of these regions also showed decreased gray matter, except insula/putamen. Hippocampal and posterior cingulate gray matter differences were significantly larger than T2* differences. Therefore, decreased T2* signal in most regions are likely to be caused by gray matter atrophy, although decreased metabolism or perhaps iron deposition are also factors that may contribute. We conclude that in FMRI studies of dementia, not only the dynamic BOLD signal (activation and deactivation) but also the average baseline signal is diminished in certain regions. The method we applied may also be used in task‐related BOLD FMRI and add to the understanding of the mechanism of task‐related group differences. Hum Brain Mapp, 2007. © 2007 Wiley‐Liss, Inc.
Nonsteroidal antiinflammatory drug use and risk of bladder cancer in the health professionals follow‐up study
Authors: Genkinger Jeanine M. , DeVivo Immaculata , Stampfer Meir J. , Giovannucci Edward , Michaud Dominique S. 
Published: February 2007

AbstractNonsteroidal antiinflammatory drugs (NSAIDs) use, particularly aspirin, may lower the risk of several cancers, including bladder. NSAIDs may reduce development of bladder tumors by decreasing inflammation, inhibiting cycloxygenase‐2, inhibiting proliferation and inducing apoptosis of cancer cells. However, acetaminophen, a major metabolite of phenacetin, may be positively associated with bladder cancer risk. Results from case‐control studies on NSAIDs and acetaminophen use and bladder cancer risk are inconsistent. We investigated the association between NSAID and acetaminophen use and bladder cancer risk in a large cohort of US males. Among 49,448 men in the Health Professionals Follow‐Up Study, 607 bladder cancer cases were confirmed during 18 years of follow‐up. Relative risks (RR) and 95% confidence intervals (CI) were calculated by Cox proportional hazards models. Multivariate RR were adjusted for age, current smoking status, pack years, geographic region and fluid intake. No significant associations were observed for regular aspirin (≥2 tablets per week), (RR = 0.99, 95% CI 0.83–1.18), ibuprofen (RR = 1.11, 95% CI 0.81–1.54), acetaminophen (RR = 0.96, 95% CI 0.67–1.39) or total NSAID use (not including acetaminophen; RR = 1.01, 95% CI 0.85–1.20) and bladder cancer risk compared with nonuse. Consistent use (over 6 years) of aspirin, ibuprofen, acetaminophen and total NSAIDs, compared to nonuse, was not associated with bladder cancer risk. No association was observed between aspirin frequency and dose and bladder cancer risk. We observed no effect‐modification by smoking, age or fluid intake. Our results suggest that regular NSAID or acetaminophen use has no substantial impact on bladder cancer risk among men. © 2007 Wiley‐Liss, Inc.
Polymorphisms at XPD and XRCC1 DNA repair loci and increased risk of oral leukoplakia and cancer among NAT2 slow acetylators
Authors: Majumder Mousumi , Sikdar Nilabja , Ghosh Saurabh , Roy Bidyut 
Published: February 2007

AbstractPolymorphisms at N‐acetyl transferase 2 locus (NAT2) lead to slow, intermediate and rapid acetylation properties of the enzyme. Improper acetylation of heterocyclic and aromatic amines, present in tobacco, might cause DNA adduct formation. Generally, DNA repair enzymes remove these adduct to escape malignancy. But, tobacco users carrying susceptible NAT2 and DNA repair loci might be at risk of oral leukoplakia and cancer. In this study, 389 controls, 224 leukoplakia and 310 cancer patients were genotyped at 5 polymorphic sites on NAT2 and 3 polymorphic sites on each of XRCC1 and XPD loci by PCR‐RFLP method to determine the risk of the diseases. None of the SNPs on these loci independently could modify the risk of the diseases in overall population but variant genotype (Gln/Gln) at codon 399 on XRCC1 and major genotype (Lys/Lys) at codon 751 on XPD were associated with increased risk of leukoplakia and cancer among slow acetylators, respectively (OR = 4.2, 95% CI = 1.2–15.0; OR = 1.6, 95% CI = 1.1–2.3, respectively). Variant genotype (Asn/Asn) at codon 312 on XPD was also associated with increased risk of cancer among rapid and intermediate acetylators (OR = 1.9, 95% CI = 1.2–2.9). Variant C‐G‐A haplotype at XRCC1 was associated with increased risk of leukoplakia (OR = 1.7, 95% CI = 1.2–2.4) but leukoplakia and cancer in mixed tobacco users (OR = 3.1, 95% CI = 1.4–7.1, OR = 2.4, 95% CI = 1.1–5.4, respectively) among slow acetylators. Although none of the 3 loci could modulate the risk of the diseases independently but 2 loci in combination, working in 2 different biochemical pathways, could do so in these patient populations. © 2007 Wiley‐Liss, Inc.
Genes and molecular pathways related to radioresistance of oral squamous cell carcinoma cells
Authors: Ishigami Takashi , Uzawa Katsuhiro , Higo Morihiro , Nomura Hitomi , Saito Kengo , Kato Yoshikuni , Nakashima Dai , Shiiba Masashi , Bukawa Hiroki , Yokoe Hidetaka , Kawata Tetsuya , Ito Hisao , Tanzawa Hideki 
Published: February 2007

AbstractTo identify genes associated with radioresistant oral squamous cell carcinoma (OSCC), we compared gene expression signatures between OSCC cell lines exhibiting radioresistance and cells with radiosensitivity after X‐ray irradiation in a dose‐dependent manner using Affymetrix GeneChip analysis with Human Genome‐U133 plus 2.0 GeneChip. The microarray data identified 167 genes that were significantly overexpressed in radioresistant cells after X‐ray irradiation. Among the genes identified, 40 were mapped to 3 highly significant genetic networks identified by the Ingenuity Pathway Analysis tool. Gene ontology analysis showed that cancer‐related function had the highest significance. The 40 genes included 25 cancer‐related genes that formed 1 network and were categorized by function into growth and proliferation, apoptosis, and adhesion. Furthermore, real‐time quantitative reverse transcriptase–polymerase chain reaction showed that the mRNA expression levels of the 25 genes were higher in radioresistant cells than in radiosensitive cells in a dose‐dependent manner and in a time‐dependent manner. Our results suggest that the identified genes help to elucidate the molecular mechanisms of the radioresistance of OSCC and could be radiotherapeutic molecular markers for choosing the appropriate radiotherapy for this disease. © 2007 Wiley‐Liss, Inc.
Cloning of genetically tagged chromosome break sequences reveals new fragile sites at 6p21 and 13q22
Authors: Fechter Anne , Buettel Isabel , Kuehnel Elisabeth , Schwab Manfred , Savelyeva Larissa 
Published: February 2007

AbstractFragile sites are specific genomic loci that are especially prone to chromosome breakage. For the human genome there are 31 rare fragile sites and 88 common fragile sites listed in the National Center for Biotechnology Information database; however, the exact number remains unknown. In this study, unstable DNA sequences, which have been previously tagged with a marker gene, were cloned and provided starting points for the characterization of two aphidicolin inducible common fragile sites. Mapping of these unstable regions with six‐color fluorescence in situ hybridization revealed two new fragile sites at 6p21 and 13q22, which encompass genomic regions of 9.3 and 3.1 Mb, respectively. According to the fragile site nomenclature they were consequently entitled as FRA6H and FRA13E. Both identified regions are known to be associated with recurrent aberrations in malignant and nonmalignant disorders. It is conceivable that these fragile sites result in genetic damage that might contribute to cancer phenotypes such as osteosarcoma, breast and prostate cancer. © 2007 Wiley‐Liss, Inc.
Inhibition of prostate carcinogenesis by combined active immunoprophylaxis
Authors: De Giovanni Carla , Croci Stefania , Nicoletti Giordano , Landuzzi Lorena , Palladini Arianna , Pannellini Tania , Borgia Ludovica , Iezzi Manuela , Di Carlo Emma , Orengo Anna Maria , Kennedy Ronald C. , Lollini Pier‐Luigi , Nanni Patrizia , Musiani Piero 
Published: February 2007

AbstractThe aim of this study is to investigate whether an active immunoprophylactic approach combining specific antigens and adjuvant stimuli would be able to inhibit prostate carcinogenesis in transgenic TRAMP mice. A vaccine consisting of allogeneic large T antigen (TAg)‐positive SV40‐transformed cells combined with systemic recombinant IL‐12 was administered to TRAMP mice, starting from when they were still tumor‐free at 5–6 weeks of age. The combined vaccine significantly inhibited prostate carcinogenesis, giving a more than doubled median latency time of prostatic tumors (53 weeks in comparison to 26 weeks in control mice). Vaccination with cells alone or IL‐12 treatment alone was poorly effective (median latency of 30 and 39 weeks, respectively). The combined vaccine induced a very high CD4 response biased toward the Th1 pathway, with the induction of a humoral response that included TAg‐specific antibodies. Therefore, such active immunoprophylactic approach based on the combination of allogeneic SV40 TAg‐positive cells and systemic administration of recombinant IL‐12 significantly delayed autochthonous urogenital carcinogenesis driven by SV40 TAg in TRAMP mice. © 2007 Wiley‐Liss, Inc.
Phosphorylation of ectopically expressed L‐plastin enhances invasiveness of human melanoma cells
Authors: Klemke Martin , Rafael Maria T. , Wabnitz Guido H. , Weschenfelder Tatjana , Konstandin Mathias H. , Garbi Natalio , Autschbach Frank , Hartschuh Wolfgang , Samstag Yvonne 
Published: February 2007

AbstractThe leukocyte specific actin‐binding protein L‐plastin is aberrantly expressed in several nonhematopoetic malignant tumors. However, little is known about the functional consequences of L‐plastin expression. Here, we investigated the function of L‐plastin in human malignant melanoma cells. Knock‐down of endogenous L‐plastin by siRNA treatment reduced migration of the melanoma cell line IF6. However, in melanoma patients, no correlation existed between L‐plastin expression and tumor stages. This implied that additional factors such as phosphorylation of L‐plastin may influence its function in tumor cells. To investigate this further, EGFP‐tagged wild‐type L‐plastin (wt‐LPL‐EGFP) and a mutated, nonphosphorylatable L‐plastin protein (5A7A‐LPL‐EGFP), were expressed in the L‐plastin negative melanoma cell line MV3. Biochemical analysis revealed that wt‐LPL‐EGFP is phosphorylated in MV3 cells while 5A7A‐LPL‐EGFP is not. Although both wt‐LPL‐EGFP and 5A7A‐LPL‐EGFP were targeted to, and promote the formation of, vinculin‐containing adhesion sites, static adhesion to either Matrigel or isolated extracellular matrix molecules was neither influenced by expression of wt‐LPL‐EGFP nor by expression of 5A7A‐LPL‐EGFP when compared with EGFP expressing control cells. In contrast, haptotactic, but not chemotactic, migration of melanoma cells towards either Matrigel or isolated extracellular matrix molecules was similarly enhanced, if either 5A7A‐LPL‐EGFP or wt‐LPL‐EGFP were expressed in MV3 cells. Interestingly, only cells expressing the phosphorylatable wt‐LPL‐EGFP protein showed enhanced invasion into Matrigel. In line with these findings the in vivo metastatic capacity of mouse B16 melanoma cells correlates with expression and phosphorylation of L‐plastin. These data show that an increase in melanoma cell invasiveness requires not only expression but also phosphorylation of L‐plastin. © 2007 Wiley‐Liss, Inc.
Adrenomedullin is induced by hypoxia and enhances pancreatic cancer cell invasion
Authors: Keleg Shereen , Kayed Hany , Jiang Xiaohua , Penzel Roland , Giese Thomas , Büchler Markus W. , Friess Helmut , Kleeff Jörg 
Published: February 2007

AbstractAdrenomedullin (ADM) is synthesized by different types of cells and acts by binding calcitonin receptor‐like receptor (CRLR) and members of the receptor activity‐modifying protein (RAMP) family. In this study, the expression and functional role of ADM and its signaling components were investigated in pancreatic adenocarcinoma (PDAC). By QRT‐PCR, median mRNA levels of ADM and CRLR were 1.5‐ and 2.4‐fold higher, respectively, in PDAC tissues compared to normal pancreatic tissues. By immunohistochemistry, ADM, CRLR, RAMP1 and RAMP2, but not RAMP3, were expressed in pancreatic cancer cells. ADM serum levels were significantly increased in PDAC patients compared to healthy controls and chronic pancreatitis (CP) patients, with an area under the ROC curve of 0.83 and 0.98, respectively. At a cut‐off level of 30.6 ng/ml, the specificity of ADM to differentiate PDAC from controls and CP patients was 85.5 and 83.6%, with a sensitivity of 80 and 100%. All 5 evaluated pancreatic cancer cells lines expressed ADM, CRLR, RAMP1 and RAMP2, whereas RAMP3 was expressed in only 1/5 pancreatic cancer cell lines. ADM was strongly induced by hypoxia and significantly increased invasiveness in 3/5 human pancreatic cancer cells. Blocking of CRLR decreased invasiveness in 4/5 human pancreatic cancer cells. In addition, rADM slightly up‐regulated vascular endothelial growth factor secretion in 3/5 cell lines. In conclusion, ADM is induced by hypoxia and over‐expressed in PDAC and might therefore serve as a potential tumor marker. Furthermore, ADM increases invasiveness of some pancreatic cancer cells and might influence angiogenesis, suggesting that blocking this pathway might have a therapeutic potential. © 2007 Wiley‐Liss, Inc.
Erratum to: “A linear vizing‐like relation relating the size and total domination number of a graph”
Authors: Shan Erfang , Kang Liying , Henning Michael A. 
Published: February 2007

AbstractThe proof of the main theorem in the paper [1] is incorrect as it is missing an important case. Here we complete the proof by giving the missing case. © 2007 Wiley Periodicals, Inc. J Graph Theory 54: 350–353, 2007