bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comprehensive Study of Concepts and Phenomena of the Nonspecific Adsorption of β‐Lactoglobulin
Authors: Rabe Michael , Verdes Dorinel , Rankl Michael , Artus Georg R. J. , Seeger Stefan 
Published: March 2007

AbstractWe investigate nonspecific protein adsorption processes by comparing experimentally measured adsorption kinetics of β‐lactoglobulin with mathematical models. The adsorption and desorption behavior of this protein on a hydrophilic glass surface in citrate buffer (pH 3.0), monitored for a large set of different bulk concentrations (0.5×10−8 M–1.5×10−6 M) using a supercritical angle fluorescence (SAF) biosensor, is reported. Increasing adsorption rates and overshootings in the beginning of the adsorption are observed as well as a transition to an almost irreversibly bound state of the protein in the long term. Furthermore, rinsing experiments prove that adsorbed proteins abruptly change their desorption behavior from irreversible to reversible when a critical surface coverage θcrit is reached. Based on all experimental observations, a mathematical model composed of three adsorbed states differing in their surface affinity is proposed. Terms to account for lateral interactions between surface‐bound proteins are included, which yield an excellent fit of the measured kinetics. For the first time, several phenomena that have been discussed in theoretical studies are confirmed by comparing experimental data with a single model.
Characterisation of Nanocrystalline Magnesium Oxide by X‐Ray Absorption Spectroscopy
Authors: Savin Shelley L. P. , Chadwick Alan V. , O'Dell Luke A. , Smith Mark E. 
Published: March 2007

AbstractThere are numerous methods of preparing nanocrystalline materials. Magnesium oxide is an ideal model system on which to probe the relation of the preparative route and the microstructure. Using X‐ray absorption spectroscopy (XAS) we show that the sol‐gel route can be used to prepare highly crystalline material provided there is careful control of the calcination conditions. In the present work this is achieved by calcining at high temperatures (at least 800 °C). However, this results in grain growth that can be prevented by the addition of a pinning agent, SiO2, during the preparation of the sol. The pinned samples maintain a particle size of 11 nm even after calcining at 1000 °C. Ball‐milling is a common method of preparing nanocrystalline oxides, however the present work shows that this produces a significant fraction of amorphous material, the fraction increasing with decreasing grain size (e.g. ≈30 % for a grain size of 23 nm).
Theoretical and experimental dynamic behaviour of a curved model bridge structure
Authors: Kawashima Kazuhiko , Penzien Joseph 
Published: March 2007

AbstractCorrelations between analytical and experimental seismic responses of a curved model bridge structure, which was constructed to have the same features as a typical full‐scale high curved highway bridge structure, are presented. Dynamic behaviour and seismic response of the experimental bridge model are examined with particular emphasis on the discontinuous behaviour of expansion joints. Modelling of Coulomb type friction with slippages and impacting at the expansion joints is described. Correlations of displacement response of the bridge model carried out for three seismic excitations are presented. Parameter studies conducted to assist in the interpretation of correlation results are presented and the characteristics of the dynamic behaviour of the bridge model are discussed.
Analytical correlation of a dynamic brace buckling experiment
Authors: Ghanaat Yusof , Clough Ray W. 
Published: March 2007

AbstractA dynamic response analysis procedure for an x‐braced tubular steel offshore platform frame is described, including details of the mathematical model adopted to represent the dynamic buckling behaviour of the brace member. Results obtained with this mathematical technique are compared with experimental data measured during shaking table tests of a 5/48 scale model frame. The agreement between experiment and analysis is excellent for different levels of response, ranging from linearly elastic to cyclic brace buckling.
Response of sliding structures to harmonic support motion
Authors: Mostaghel N. , Hejazi M. , Tanbakuchi J. 
Published: March 2007

AbstractThe problem of response of a single degree of freedom structure supported on a sliding foundation and subjected to harmonic support motions is considered. The non‐linear governing equations of motion are derived. It turns out that these equations are linear in each sliding and non‐sliding phase and can be solved in closed forms in each phase. The equations for evaluation of the beginning and ending times of different phases are also formulated and solved numerically. The response for different coefficients of friction and various levels of excitation is evaluated and presented graphically. It is concluded that sliding supports can be quite effective in isolating structures from support excitations.
Dynamics of flexible systems with partial lift‐off
Authors: Psycharis Ioannis N. 
Published: March 2007

AbstractThe dynamic behaviour of a simplified model of a multi‐storey building, supported by an elastic foundation and allowed to uplift, is examined. The building is modelled by an n‐degree‐of‐freedom oscillator, while the foundation is represented by a viscously damped two‐spring model which permits uplift. This model has been shown in previous studies to be an accurate approximation to the more realistic but more complex Winkler foundation. Approximate values for the characteristic frequencies of the interacting system are presented and a simple, first‐mode solution is developed. The response of the system is non‐linear and the apparent fundamental period increases with the amount of lift‐off. In contrast to the first mode of the superstructure which participates strongly in the interaction, the second and higher modes of the building are not affected significantly by either the interaction with the soil or the uplift. The study shows that lift‐off results in larger rocking motion of the structure, but it is not clear from the analysis and the example whether the interfloor displacements are consistently increased or decreased, since this appears to depend on the properties of the system and the excitation.
Soil‐structure interaction with Rayleigh waves
Authors: Gómez‐Massó Alberto , Lysmer John , Chen Jian‐Chu , Seed H. Bolton 
Published: March 2007

AbstractPresented is a plane‐strain method for soil‐structure interaction analysis consisting of the superposition of the free field motions and the interaction motions in a generalized seismic environment.The free field is modelled as a horizontally layered viscoelastic medium and the seismic environment may consist of a combination of S, P and Rayleigh waves. The soil‐structure system is modelled with viscoelastic finite elements, transmitting boundaries, viscous boundaries and a three‐dimensional simulation.Comparative analyses of the same structure are conducted for an input of R waves and for vertically propagating S and P waves in a rock site and sand site. In the rock site the R waves produce higher peak horizontal spectral acceleration up to 25 per cent, and a significant rocking effect at points away from the centre of gravity of the structure. However, the S and P waves show higher peak vertical spectral acceleration by up to 15 per cent at the centre of the structure. Very similar horizontal response, but higher vertical response only at the centre of the structure for S and P waves, is obtained for the sand site.
The comparative performance of seismic response spectrum combination rules in building analysis
Authors: Maison B. F. , Neuss C. F. , Kasai K. 
Published: March 2007

AbstractThe peak dynamic responses of two mathematical models of a fifteen‐storey steel moment resisting frame building subjected to three earthquake excitations are computed by the response spectrum and time history methods. The models examined are: a ‘regular’ building in which the centres of stiffness and mass are coincident resulting in uncoupled modes with well‐separated periods in each component direction of response; and an ‘irregular’ building with the mass offset from the stiffness centre of the building causing coupled modes with the translational modes having closely spaced periods. Four response spectrum modal combination rules are discussed and are used to predict the peak responses: (1) the square root of the sum of the squares (SRSS) method; (2) the double sum combination (DSC) method; (3) the complete quadratic combination (CQC) method; and (4) the absolute sum (ABS) method. The response spectrum results are compared to the corresponding peak time history values to evaluate the accuracy of the different combination rules. The DSC and the CQC methods provide good peak response estimates for both the regular and irregular building models. The SRSS method provides good peak response estimates for the regular building, but yields significant errors in the irregular building response estimates. The poor accuracy in the irregular building results is attributable to the effects of coupled modes with closely spaced periods. It is concluded that the DSC and CQC methods produce response estimates of equivalent accuracy. Both methods are recommended for general use. In addition to the DSC and CQC rules, the SRSS method is recommended for systems where coupled modes with closely spaced periods do not dominate the response.
Bridge response with tractor‐trailer vehicle loading
Authors: Mulcahy N. Lex 
Published: March 2007

AbstractA method for the calculation of dynamic response and loading of single span multigirder bridges due to vehicle loads is described. The analysis takes account of vehicle acceleration or braking, road surface roughness and eccentric placement of the vehicle on the bridge. The analysis is presented for a three‐axle tractor‐trailer vehicle and the bridge is modelled as an orthotropic plate using higher order finite strips.As an example application, the loadings produced with braking of the three‐axle vehicle and a nominally equivalent two‐axle vehicle on a bridge were computed. Previous theoretical studies of bridge loading with vehicle braking had employed a two‐axle idealization of a three‐axle vehicle. The results of the present study show that this approximation is not valid for braking studies as the behaviour of the two vehicle models is significantly different. The loadings produced by a three‐axle vehicle are generally less severe than those due to an ‘equivalent’ two‐axle vehicle.
Decoupling approximation to the evaluation of earthquake‐induced plastic slip in earth dams
Authors: Lin Jeen‐Shang , Whitman Robert V. 
Published: March 2007

AbstractNewmark's sliding block analysis for evaluating earthquake‐induced permanent displacements of earth dams and slopes did not consider the effects of elastic dynamic response. Makdisi and Seed extended the analysis to include such effects, using the simpfying assumption that the computation of dynamic response and plastic slip can be decoupled. This paper examines the error introduced by this assumption, using three idealized lumped‐mass models for a dam. Both sinusoidal and synthetic earthquake motions are employed. When the predominant frequency of the input motion lies in the proximity of the fundamental frequency of the dam, the slip based upon the decoupling assumption exceeds the exact value. This error decreases as the threshold acceleration required to initiate slip and the damping in the soil increase. For practical application, the error should seldom exceed 20 per cent.
On the application of the mode‐acceleration method to structural engineering problems
Authors: Cornwell R. E. , Craig R. R. , Johnson C. P. 
Published: March 2007

AbstractMode‐superposition has been extensively used in computing the dynamic response of complex structures. Two versions of mode‐superposition, namely the mode‐displacement method and the mode‐acceleration method, have been employed. The present paper summarizes the results of a systematic study comparing the accuracy of the mode‐displacement and mode‐acceleration methods when applied to structures with various levels of damping or various excitation frequencies. The paper also discusses several details concerning the implementation of the mode‐acceleration method.
Acanthodian remains from the Middle‐Late Permian of Brazil
Authors: Mutter Raoul J. , Richter Martha 
Published: March 2007

AbstractAcanthodian fishes have been recorded from Silurian through to Permian rocks. Bone beds in the Teresina Formation of the Passa Dois Group (Paraná Basin) in São Gabriel, State of Rio Grande do Sul (southern Brazil) have yielded acanthodian scales and fin spine fragments and are preserved in association with shark and lower actinopterygian fish scales and teeth and possible shark fin spines. All fish remains are disarticulated and preservation is often fragmentary. However, there is no geological or palaeontological evidence that the materials in these bone beds, of Middle‐Late Permian age, could have been re‐worked from older strata. We therefore interpret these bone beds and the acanthodian remains as the youngest known record of acanthodians worldwide. The presence of acanthodians in the Passa Dois Group enhances the significance of the Middle‐Upper Permian rocks of the Paraná Basin in South America in interregional correlation, and may contribute to the discussion of the allegedly global mass extinction event at the end of the Palaeozoic era. Copyright © 2007 John Wiley & Sons, Ltd.
Chemiluminescent determination of leukocyte alkaline phosphatase: an advantageous alternative to the cytochemical assay
Authors: Kanegae Marília P.P. , Ximenes Valdecir F. , Falcão Roberto P. , Colturato Virgílio A.R. , de Mattos Éderson R. , Brunetti Iguatemy L. , da Fonseca Luiz Marcos 
Published: March 2007

AbstractThe determination of leukocyte alkaline phosphatase (LAP) is used as an aid to diagnose many diseases in the laboratory. For example, it can be used to distinguish chronic myeloid leukemia (CML) from other myeloproliferative disorders (particularly myelofibrosis and polycythemia) and leukemoid reactions (LR). Traditionally, this test is performed with the use of subjective cytochemical assays that assign a score to the level of LAP. Here we present a nonsubjective, quantitative, sensitive, and inexpensive chemiluminescent technique that determines LAP based on the commercial reagent Immulite® (AMPPD). To validate this methodology, intact leukocytes obtained from 32 healthy subjects, nine CML patients, and nine LR patients were submitted to the optimized protocol. By measuring the light emission elicited by four concentrations of neutrophils, we were able to estimate the activity of LAP per cell (the slope of the curve obtained by linear regression). A high linear correlation was found between the chemiluminescent result (slope) and the cytochemical score. The slope for healthy individuals ranged between 0.61 and 8.49 (10–5 mV.s/cell), with a median of 2.04 (10–5 mV.s/cell). These results were statistically different from those of CML patients (range=0.07–1.75, median=0.79) and LR patients (range= 3.84–47.24, median=9.58; P<0.05). J. Clin. Lab. Anal. 21:91–96, 2007. © 2007 Wiley‐Liss, Inc.
A modification of the kinetic determination of pancuronium bromide based on its inhibitory effect on cholinesterase
Authors: Stankov‐Jovanovic V.P. , Nikolic‐Mandic S.D. , Mandic Lj.M. , Mitic V.D. 
Published: March 2007

AbstractA modification of the existing spectrophotometric kinetic method for the determination of pancuronium bromide (PCBr), based on pooled human serum cholinesterase (ChE, EC 3.1.1.8 acylcholine acylhydrolase) inhibition, was developed. Butyrylthiocholine iodide (concentration 1.667 mmol/L) was used as substrate and determination was performed at pH 7.6. Essential basic kinetic parameters were also determined: Michaelis‐Menten's constant KM=0.33 mmol/L, maximal reaction rate Vmax=42.29 µmol/L min, inhibition constant KI=0.34 µmol/L, and IC50=0.235 µmol/L. Linear dependence between the reaction rate and the inhibitor concentration exists in PCBr concentration range 8.29–265.28 nmol/L, which corresponds to the real sample concentrations from 0.166 to 5.306 µmol/L. The method detection limit was established to be 1.86 nmol/L and the quantification limit was 6.18 nmol/L. Precision of the method was tested for three pancuronium concentrations (16.58, 99.48, and 198.96 nmol/L). The relative standard deviation (RSD) was in the range 0.78–5.13%. Accuracy was examined by the standard addition method. The influence of substances usually present in serum and urine on the reaction rate was determined. The method developed was applied for PCBr determination in spiked serum and urine samples and in the urine taken during surgery. The method was proven to have good sensitivity, accuracy, and precision and can be considered suitable for clinical practice. J. Clin. Lab. Anal. 21:124–131, 2007. © 2007 Wiley‐Liss, Inc.
Puromycin insensitive leucyl‐specific aminopeptidase (PILSAP) affects RhoA activation in endothelial cells
Authors: Suzuki Takahiro , Abe Mayumi , Miyashita Hiroki , Kobayashi Toshimitsu , Sato Yasufumi 
Published: March 2007

AbstractPuromycin insensitive leucyl‐specific aminopeptidase (PILSAP) expressed in endothelial cells (ECs) plays an important role in angiogenesis due to its involvement in migration, proliferation and network formation. Here we examined the biological function of PILSAP with respect to EC morphogenesis and the related intracellular signaling for this process. When mouse endothelial MSS31 cells were cultured, a dominant negative PILSAP mutant converted cell shape to disk‐like morphology, blocked stress fiber formation, and augmented membrane ruffling in random directions. These phenotypic changes led us to test whether PILSAP affected activities of Rho family small G‐proteins. Abrogation of PILSAP enzymatic activity or its expression attenuated RhoA but not Rac1 activation during cell adhesion. This attenuation of RhoA activation was also evident when G‐protein coupled receptors such as proteinase‐activated receptor or lysophosphatidic acid receptor were activated in ECs. These results indicate that PILSAP affects RhoA activation and that influences the proper function of ECs. J. Cell. Physiol. 211: 708–715, 2007. © 2007 Wiley‐Liss, Inc.
cDNA‐AFLP analysis of differential gene expression in human hepatoma cells (HepG2) upon dengue virus infection
Authors: Ekkapongpisit Maneerat , Wannatung Tirawat , Susantad Tharinee , Triwitayakorn Kanokporn , Smith Duncan R. 
Published: March 2007

AbstractIn infectious diseases, the disease pathogenesis is the outcome of the interaction between the genome of the host and the genome of the pathogen. Despite the wide distribution of dengue infections in the world, and the large number of annual infections, few studies have investigated how the dengue genome alters the global transcriptional profile of the host cell. To investigate alterations in the liver cell transcriptome in response to dengue virus infection, liver cells (HepG2) were infected with dengue serotype 2 at MOI 5 and at 3 days post‐infection RNA extracted and analyzed by cDNA‐AFLP in parallel with mock‐infected cells. From 73 primer combinations over 5,000 transcription‐derived fragments (TDFs) were observed, of which approximately 10% were regulated differentially in response to infection. Sixty‐five TDFs were subsequently cloned and sequenced and 27 unique gene transcripts identified. Semi‐quantitative reverse transcription (RT)‐PCR was used to validate the expression of 12 of these genes and 10 transcripts (CK2, KIAA509, HSP70, AK3L, NIPA, PHIP, RiboS4, JEM‐1, MALT1, and HSI12044) were confirmed to be differentially regulated, with four transcripts (HSP70, NIPA, RiboS4, and JEM‐1) showing a greater than twofold regulation. These results suggest that the expression of a large number of genes is altered in response to dengue virus infection of liver cells, and that cDNA‐AFLP is a useful tool for obtaining information on both characterized and as yet uncharacterized transcripts whose expression is altered during the infection process. J. Med. Virol. 79:552–561, 2007. © 2007 Wiley‐Liss, Inc.
Molecular epidemiology of hepatitis A virus in a group of Portuguese citizens living in Lisbon area
Authors: Rodrigues L. , Pista A. , Oliveira A. , Água‐Doce I. , Manita C. , Paixão M.T. 
Published: March 2007

AbstractHepatitis A virus (HAV) is the most important cause of acute infectious hepatitis worldwide. In Portugal, due to improvements in sanitation epidemic outbreaks of HAV infection have become less frequent. This report is the first, to our knowledge that characterized HAV in Portugal. For the detection and molecular characterization of HAV cases in a group of Portuguese individuals in the Lisbon area, 31 serum samples were tested: 8 from symptomatic children from an acute hepatitis A outbreak in a Roma (Gipsies) community (2004–2005), and 22 from patients with acute HAV from sporadic cases (2005–2006). A sample of CSF involved in a case of meningitis was also included. IgM anti‐HAV detection and nested reverse transcription (RT‐PCR), with primers located at the VP1‐P2a region, was undertaken to detect HAV genome. In positive samples, molecular characterization was followed by phylogenetic analysis. All samples (n = 31) were positive for IgM anti‐HAV. HAV RNA was found in 96.7% of cases. All isolates were classified as genotype I: 22 belonged to sub‐genotype IA (73.3%), and 8 to sub‐genotype IB (26.7%). All strains obtained from an acute HAV outbreak had sub‐genotype IA, in which seven isolates (87.5%) had identical sequences. In HAV sporadic cases sub‐genotypes IA and IB were identified, and this may reflect the co‐circulation of these two sub‐genotypes in Portugal. Molecular epidemiology of HAV infection in this group of Portuguese appears to be similar to other European countries. HAV phylogenetic studies can provide important information for the design of appropriate public health measures. J. Med. Virol. 79:483–487, 2007. © 2007 Wiley‐Liss, Inc.