bluuebunny/crossref_metadata_2025_split huggingface dataset:
Repair of oxidized purines and damaged pyrimidines by E. coli Fpg protein: Different roles of proline 2 and lysine 57 residues
Authors: Saparbaev Murat , Sidorkina Olga M. , Jurado Juan , Privezentzev Cyril V. , Greenberg Marc M. , Laval Jacques 
Published: August 2002

AbstractThe Escherichia coli Fpg protein is involved in the repair of oxidized purines, including the highly mutagenic 7,8‐dihydro‐8‐oxoguanine (8‐oxoG). The Fpg protein also excises various oxidized pyrimidines with high efficiency. We examined, by targeted mutagenesis, the role of two highly conserved amino acid residues, proline 2 (P2) and lysine 57 (K57), on the catalytic activities of the Fpg protein toward a ring‐fragmentation product of thymine (αRT) and 5,6‐dihydrothymine (dHT). The following E. coli mutant Fpg proteins were investigated: lysine 57 → glycine (FpgK57G), proline 2 → glycine (FpgP2G), and proline 2 → glutamic acid (FpgP2E). The FpgK57G protein had barely detectable αRT and dHT‐DNA glycosylase activities and produced minute amounts of a Schiff‐base complex upon reaction with αRT containing DNA. In contrast, the activity of an FpgP2G mutant toward αRT was comparable to the wild type activity and produced a Schiff‐base complex with this substrate. FpgP2E was completely inactive in all the assays, in contrast, to the other mutants. The crystal structure of a homologous Fpg protein from an extreme thermophile, Thermus thermophilus HB8, reveals that it is composed of two distinct domains connected by a flexible hinge (Sugahara et al. [2000]: EMBO J 19:3857–3869). The N‐terminal proline, one primary residue for enzymatic catalysis, is positioned at the bottom of a cleft in close proximity to lysine 52 (analogous to K57 of the E. coli Fpg). Based on the biochemical assays, together with the crystal structure of T. thermophilus HB8 Fpg protein, we propose a two‐nucleophile model for the enzymatic catalysis. Environ. Mol. Mutagen. 39:10–17, 2002 © 2002 Wiley‐Liss, Inc.
Constrained multivariate trend analysis applied to water quality variables
Authors: Cooper D. M. , Evans C. D. 
Published: August 2002

AbstractConstrained multivariate regression analysis is used to model trends and seasonal effects in time series measurements of water quality variables. The constraint used ensures that when identifying trends the scientifically important charge balance of model‐fitted concentrations is maintained, while accounting for between variable dependencies. The analysis is a special case of linear reduction of dimensionality which preserves the integrity of a subset of the original variables, while allowing the remainder to be identified as linear combinations of this subset. The technique is applied to water quality measurements made at the outflow from Loch Grannoch, an acid‐sensitive loch in Scotland.A reduction in marine ion concentrations is observed in water samples collected four times a year over the period 1988–2000. This is identified with long term variability in the marine component in rainfall. Separation of the non‐marine component of the solute load shows a reduction in non‐marine sulphate and calcium concentrations, and an increase in the non‐marine sodium concentration. There is no significant change in either alkalinity or acid neutralizing capacity over the period. The reduction in non‐marine sulphate is consistent with reductions in atmospheric inputs of sulphate. However, the reduction in sulphate has not been accompanied by a reduction in the acidity of water samples from Loch Grannoch, but with a reduction in calcium concentration and an apparent increase in organic acids, as evidenced by increased dissolved organic carbon concentrations, with possible increases in nitrate and non‐marine sodium concentrations. Copyright © 2002 John Wiley & Sons, Ltd.
Generic frame model for simulation of earthquake responses of steel moment frames
Authors: Nakashima Masayoshi , Ogawa Koji , Inoue Kazuo 
Published: August 2002

AbstractThis paper presents a generic frame (GF) model useful for the simulation of earthquake responses of steel moment frames. Adopting the assumption that all rotations at joints lying at each floor level are identical, the model requires the solution of significantly fewer degrees of freedom than models with member‐by‐member representation. Procedures to construct a GF model that represents a multi‐storey, multi‐span frame are detailed. The model can allow for panel zone behaviour as well. The accuracy of the GF model in predicting maximum storey drifts and member plastic rotations is calibrated for two example frames against a variety of ground motions. Errors associated with the model are found to be negligible in light of the variability of responses attached to randomness and uncertainties of earthquake ground motions. The GF model is effective in conducting extensive numerical analyses needed for the identification and characterization of primary structural parameters that control the earthquake responses of steel moment frames, thereby contributing to further advancement of performance‐based design. Copyright © 2001 John Wiley & Sons, Ltd.
Response of tall buildings to weak long distance earthquakes
Authors: Brownjohn James Mark William , Pan Tso Chien 
Published: August 2002

AbstractIn the last decade, two tall buildings in Singapore were instrumented with accelerometers and anemometers for the original purpose of identifying the characteristics and effects of wind loading. During the monitoring it became clear that the largest acceleration responses should result from ground motions due to earthquakes having magnitudes between 6 and 8 and epicentres at least 350 km distant. The paper describes the strategy for identifying and capturing the signals from distant tremors, which depends on tracking the RMS response levels in the second vibration mode. Characteristics of some recorded signals are given. While response levels are generally small, the frequency content coincides with the range of fundamental mode frequencies for high rise residential buildings. The validity of using a tall building as a ‘weak‐motion’ seismograph is discussed by considering the mode shape of the building and the measured transfer function between basement and roof responses. Copyright © 2001 John Wiley & Sons, Ltd.
Optimal displacement feedback control law for active tuned mass damper
Authors: Nagashima Ichiro 
Published: August 2002

AbstractOptimal displacement feedback control law is derived for a vibration control of a single‐degree‐of‐freedom structure with an active tuned mass damper (ATMD). Analytical expressions of the linear quadratic regulator (LQR) feedback gains for the ATMD are derived by solving the Ricatti equation straightforwardly. Based on these solutions, it is found that if the stiffness of the tuned mass damper (TMD) is calibrated to satisfy a certain condition, the control law is simplified to be composed of the feedback gains only for the displacement of the structure and the velocity of the auxiliary mass stroke, which is referred to as ‘optimal displacement feedback control’. The mean‐square responses of the structure as well as the auxiliary mass against Gaussian white noise excitations are evaluated by solving the Lyapunov equation analytically based on the stochastic optimal control theory. Using these analytical solutions, the optimal damping parameter for the auxiliary mass is also derived. Finally, the optimal displacement feedback control law is presented. Copyright © 2001 John Wiley & Sons, Ltd.
Direct observation of frost wedging in alpine bedrock
Authors: Matsuoka Norikazu 
Published: August 2002

AbstractWidth and temperature of rock joints were automatically monitored in the Japanese Alps. Three years of monitoring on a sandstone rock face shows two seasonal peaks of joint widening in autumn and spring. The autumn events are associated with short‐term freeze–thaw cycles, and the magnitude of widening reflects the freezing intensity and water availability. The short‐term freezing can produce wedging to a depth of at least 20 cm. The spring events follow a rise in the rock surface temperature to 0 °C beneath the seasonal snowcover, and likely originate from refreezing of meltwater entering the joint. Some of these events contribute to permanent enlargement of the joint. Two other joints on nearby rock faces experience only sporadic widening accompanying freeze–thaw cycles and insignificant permanent enlargement. Observations indicate that no single thermal criterion can explain frost weathering. The temperature range at which wedging occurs varies with the bedrock conditions, water availability and duration of freezing. Copyright © 2001 John Wiley & Sons, Ltd.
GRADISTAT: a grain size distribution and statistics package for the analysis of unconsolidated sediments
Authors: Blott Simon J. , Pye Kenneth 
Published: August 2002

AbstractGrain size analysis is an essential tool for classifying sedimentary environments. The calculation of statistics for many samples can, however, be a laborious process. A computer program called GRADISTAT has been written for the rapid analysis of grain size statistics from any of the standard measuring techniques, such as sieving and laser granulometry. Mean, mode, sorting, skewness and other statistics are calculated arithmetically and geometrically (in metric units) and logarithmically (in phi units) using moment and Folk and Ward graphical methods. Method comparison has allowed Folk and Ward descriptive terms to be assigned to moments statistics. Results indicate that Folk and Ward measures, expressed in metric units, appear to provide the most robust basis for routine comparisons of compositionally variable sediments. The program runs within the Microsoft Excel spreadsheet package and is extremely versatile, accepting standard and non‐standard size data, and producing a range of graphical outputs including frequency and ternary plots. Copyright © 2001 John Wiley & Sons, Ltd.
Composition and chemical variability of the needle essential oil of Pinus nigra subsp. laricio from corsica
Authors: Rezzi Serge , Bighelli Ange , Mouillot David , Casanova Joseph 
Published: August 2002

AbstractThe composition of 123 samples of needle essential oil of individual trees of Pinus nigra subsp. laricio from Corsica was investigated by GC and 13C‐NMR. α‐Pinene, manoyl oxide, germacrene‐D, myrcene, (E)‐caryophyllene and limonene were found to be the main constituents. The results were submitted to principal components analysis and K‐means partitioning which allowed two groups of essential oils to be identified with respect to their content of α‐pinene, manoyl oxide and germacrene‐D. Copyright © 2001 John Wiley & Sons, Ltd.
A fully coupled numerical technique for 2D bed morphology calculations
Authors: Soulis Johannes V. 
Published: August 2002

AbstractA fully coupled two‐dimensional subcritical and/or supercritical, viscous, free‐surface flow numerical model is developed to calculate bed variations in alluvial channels. Vertically averaged free‐surface flow equations in conjunction with sediment transport equation are numerically solved using an explicit finite‐volume scheme using transformed grid in order to handle complex geometry fluvial problems. Convergence is accelerated with use of a multi‐grid technique. Firstly the capabilities of the proposed method are demonstrated by analyzing subcritical and supercritical hydrodynamic flows. Thereafter, an analysis of one‐ and two‐dimensional flows is performed referring to aggradation and scouring. For all reported test cases the computed results compare reasonably well with measurements as well as with other numerical solutions. The method is stable, reliable and accurate handling a variety of sediment transport equations with rapid changes of sediment transport at the boundaries. Copyright © 2002 John Wiley & Sons, Ltd.
Option‐Expiration Effects in Small Markets: The Spanish Stock Exchange
Authors: Corredor P. , Lechón P. , Santamaría R. 
Published: August 2002

AbstractThis study analyzes the effect of the expiration of the Ibex‐35 Index derivatives, as well as the
first four stock options traded in the Spanish Equity Derivatives Exchange, on the return, conditional
volatility, and trading volume of the underlying assets. The analysis covers the period from the introduction of
the various derivatives to December 1995. This period has been divided into two subperiods in order to determine
if there are changes in the conclusions. The expiration of the Ibex‐35 index derivatives is associated
with an increase in the trading volume of the underlying asset, but it has no significant effect on either the
underlying asset prices or on the level of volatility on the expiration day. However, the expiration of the
stock options has significant impact on their underlying assets. We observed a downward pressure on prices and a
reduction of volatility level in the week before the expiration date and a significant increase in trading
volume on the expiration day. The absence of futures contracts on individual stocks, among other possible
causes, may explain these differences. © 2001 John Wiley & Sons, Inc. Jrl Fut Mark 21:905–928,
2001
Stratified case sampling and the use of family controls
Authors: Siegmund Kimberly D. , Langholz Bryan 
Published: August 2002

AbstractWe compare the asymptotic relative efficiency (ARE) of different study designs for estimating gene and gene‐environment interaction effects using matched case‐control data. In the sampling schemes considered, cases are selected differentially based on their family history of disease. Controls are selected either from unrelated subjects or from among the case’s unaffected siblings and cousins. Parameters are estimated using weighted conditional logistic regression, where the likelihood contributions for each subject are weighted by the fraction of cases sampled sharing the same family history. Results showed that compared to random sampling, over‐sampling cases with a positive family history increased the efficiency for estimating the main effect of a gene for sib‐control designs (103–254% ARE) and decreased efficiency for cousin‐control and population‐control designs (68–94% ARE and 67–84% ARE, respectively). Population controls and random sampling of cases were most efficient for a recessive gene or a dominant gene with an relative risk less than 9. For estimating gene‐environment interactions, over‐sampling positive‐family‐history cases again led to increased efficiency using sib controls (111–180% ARE) and decreased efficiency using population controls (68–87% ARE). Using case‐cousin pairs, the results differed based on the genetic model and the size of the interaction effect; biased sampling was only slightly more efficient than random sampling for large interaction effects under a dominant gene model (relative risk ratio = 8, 106% ARE). Overall, the most efficient study design for studying gene‐environment interaction was the case‐sib‐control design with over‐sampling of positive‐family‐history‐cases. Genet. Epidemiol. 20:316–327, 2001. © 2001 Wiley‐Liss, Inc.
Gibbs sampling–based segregation analysis of asthma‐associated quantitative traits in a population‐based sample of nuclear families
Authors: Palmer Lyle J. , Cookson William O.C.M. , James Alan L. , Musk A. William , Burton Paul R. 
Published: August 2002

AbstractAsthma is a common, complex human disease. Elevated serum immunoglobulin E (IgE) levels, elevated blood eosinophil counts, and increased airway responsiveness are physiological traits that are characteristic of asthma. Few studies have investigated major gene effects for these traits in a population‐based sample. Further, it is not known if any putative major genes may be common to two or more of these traits. We investigated the existence and nature of major genes modulating asthma‐associated quantitative traits in an Australian population‐based sample of 210 Caucasian nuclear families. The sharing of these major genes was also investigated. Segregation analysis was based upon a Markov Chain Monte Carlo (Gibbs sampling) approach as implemented in the program BUGS v0.6. All models included adjustment for age, height, tobacco smoke exposure, and gender. The segregation of total IgE levels, blood eosinophil counts, and dose‐response slope (DRS) of methacholine challenge were all consistent with major loci at which a recessive allele acted to increase or decrease the phenotype. The respective estimated frequencies of the recessive alleles were 68% (total IgE), 10% (blood eosinophil count), and 27% (DRS). Extensive modelling suggested that the major loci controlling total serum IgE levels, blood eosinophil counts, and airway responsiveness represent different genes. These data provide evidence, for the first time, of the existence of at least 3 distinct genetic pathways involving major gene effects on physiological traits closely associated with asthma. These results have implications for gene discovery programs. Genet. Epidemiol. 20:356–372, 2001. © 2001 Wiley‐Liss, Inc.
Fast and precise independent component analysis for high field fMRI time series tailored using prior information on spatiotemporal structure
Authors: Suzuki Kiyotaka , Kiryu Tohru , Nakada Tsutomu 
Published: August 2002

AbstractIndependent component analysis (ICA) has been shown as a promising tool for the analysis of functional magnetic resonance imaging (fMRI) time series. Each of these studies, however, used a general‐purpose algorithm for performing ICA and the computational efficiency and accuracy of elicited neuronal activations have not been discussed in much detail. We have previously proposed a direct search method for improving computational efficiency. The method, which is based on independent component‐cross correlation‐sequential epoch (ICS) analysis, utilizes a form of the fixed‐point ICA algorithm and considerably reduces the time required for extracting desired components. At the same time, it is shown that the accuracy of detecting physiologically meaningful components is much improved by tailoring the contrast function used in the algorithm. In this study, further improvement was made to this direct search method by integrating an optimal contrast function. Functional resolution of activation maps could be controlled with a suitable selection of the contrast function derived from prior knowledge of the spatial patterns of physiologically desired components. A simple skewness‐weighted contrast function was verified to extract sufficiently precise activation maps from the fMRI time series acquired using a 3.0 Tesla MRI system. Hum. Brain Mapping 15:54–66, 2001. © 2001 Wiley‐Liss, Inc.
Equity in Swedish health care reconsidered: new results based on the finite mixture model
Authors: Gerdtham Ulf‐G. , Trivedi Pravin K. 
Published: August 2002

AbstractThis paper reconsiders the equity issue in Swedish health care utilization previously analysed by Gerdtham (Health Econ 1997; 6: 303–319) within the framework of the standard two‐part model. Departing from the user/non‐user distinction, we use the more flexible framework of the finite mixture model that distinguishes between frequent/infrequent users. Our results indicate that the support for the inequity hypothesis reported by Gerdtham is sensitive to model specification and the way standard errors of coefficients are estimated. The new framework offers an alternative perspective on the magnitude of the income‐related difference in health care utilization. Copyright © 2001 John Wiley & Sons, Ltd.
Effects of lingual gestures on blood flow into the tongue: A pilot study
Authors: Watkin Kenneth L. , Gallagher Tanya M. , Logemann Jeri A. , Rademaker Alfred W. 
Published: August 2002

AbstractBackgroundReduced blood flow has been hypothesized to be a major factor in the formation of postradiation fibrosis. This study examined Doppler ultrasonography as a technique to detect changes in blood flow into the tongue during selected lingual gestures, /t/ and /k/.MethodsSix normal subjects, three young men (mean age, 26 years) and three older men (mean age, 66 years) were examined in an upright position using Doppler ultrasound imaging of the external carotid artery just below the lingual artery. Measurements were made with a standardized segmentation technique before and after three repetitions of four speech production gestures /t/ and /k/, each with natural and maximal force.ResultsBlood flow peak systole increased significantly after the speech gestures (p < .001). Pooled before and after gesture values for older subjects were significantly lower than those for younger subjects (p ≤ .05).ConclusionsUltrasonography is a clinically useful technique for measuring blood flow during a dynamic gesture and may be useful for measuring effects of tumor treatment and in a lingual exercise program. © 2001 John Wiley & Sons, Inc. Head Neck 23: 404–408, 2001.
Malignant triton tumor of the nasal cavity
Authors: Kim Seon Tae , Kim Chan Woo , Han Gyu Cheol , Park Chan , Jang II Hwan , Cha Heung Eog , Choi Geon , Lee Heung‐Man 
Published: August 2002

AbstractBackgroundMalignant triton tumor is usually an aggressive sarcoma consisting of a malignant schwannoma with rhabdomyoblastic differentiation. However, malignant triton tumor of the nasal cavity is very rare.MethodsA case report of a 38‐year‐old woman with polypoid mass, which bled easily in the right nasal cavity, and nasal obstruction is presented with a review of the literature pertaining to this unusual case.ResultsThe malignant triton tumor was treated with wide surgical excision followed by radiation therapy. Histopathological diagnosis of the malignant triton tumor was made on the surgical specimen. The patient's postoperative course was unremarkable, and follow‐up at 5 years reveals no evidence of disease.ConclusionsA malignant triton tumor in the nasal cavity is a rare disease. Head and neck surgeons should recognize the possibility of malignant triton tumor occurring in the nasal cavity. © 2001 John Wiley & Sons, Inc. Head Neck 23: 1075–1078, 2001.
Aberrant synaptic transmission in the hippocampal CA3 region and cognitive deterioration in protein‐repair enzyme‐deficient mice
Authors: Ikegaya Yuji , Yamada Mitsunori , Fukuda Tetsuya , Kuroyanagi Hidehito , Shirasawa Takuji , Nishiyama Nobuyoshi 
Published: August 2002

AbstractL‐aspartate is the amino‐acid residue most susceptible to spontaneous isomerization. This denaturation causes an alteration in the biological activity of the protein and is regarded as an aging process of the protein. Protein L‐isoaspartyl methyltransferase (PIMT) repairs this posttranslational modification and thus is implicated in retarding the aging process of proteins. PIMT is highly expressed in the brain, and its deficiency results in progressive epilepsy after 4 weeks of age, with a fatal seizure in mice. Here we report the pathophysiological role of this repair system in the hippocampal slice of PIMT‐deficient mice. The hippocampal mossy fiber‐CA3 synapses of PIMT‐deficient mice showed hyperexcitation that was repressed by a γ‐aminobutyric acid (GABA)A receptor agonist muscimol. In addition, the mossy fiber‐CA3 synapses failed to show long‐term potentiation or paired‐pulse facilitation. No abnormality, however, was observed in Schaffer collateral‐CA1 synapses or in perforant path‐dentate gyrus synapses. Electron microscopic study revealed aberrant distribution of synaptic vesicles in the mossy fiber terminals and vacuolar degeneration at the axon hillock of dentate granule cells in PIMT‐deficient mice. Furthermore, the PIMT‐deficient mice showed impaired spatial memory in Morris water maze test and exhibited fewer anxiety‐related behaviors in the elevated‐plus test. These results suggest that the mossy fiber‐CA3 system is vulnerable to aspartate isomerization and that the PIMT‐mediated repair system is essential for maintenance of normal functions of the hippocampus. Hippocampus 2001;11:287–298. © 2001 Wiley‐Liss, Inc.