bluuebunny/crossref_metadata_2025 huggingface dataset:
Parasagittal Meningioma in a Middle-aged Female Harbouring Metastatic Ductal Carcinoma: A Rare Case of Incidentally Detected Tumour-to-tumour Metastasis
Authors: Shirazi Nadia , Pandey Sanjeev , Harsh Meena , Tyagi Siddhartha
Published: March 2024

Metastasis of a tumour particularly coming from breast into an intracranial meningioma is a rare phenomenon. Several factors related to tumour microenvironment have been suggested in the pathophysiology of these lesions, particularly the rich vascular network of meningiomas, expression of common hormonal receptors like Oestrogen Receptor (ER) and Progesterone Receptor (PR), local immunosuppression, and presence of cell adhesion molecules. Here, we present a clinicoradiologically unsuspecting case of intracranial, parasagittal meningioma who was operated for relief of symptoms of mass effect and was incidentally detected with tumour metastasis within the meningioma. A 50-year-old female presented with seizures, headache and visual disturbances since last one month. Radiology revealed a parasagittal mass which was likely to be meningioma. The patient was operated. On histopathology, a low-grade meningioma was seen with areas of metastatic adenocarcinoma. The metastatic foci were surrounded by fibroblastic meningioma cells. On Immunohistochemistry (IHC), the metastatic tumour cells were strongly positive for PR and Cytokeratin 7 (CK7) and a diagnosis of fibroblastic meningioma with intratumoural metastasis of ductal carcinoma was rendered. The patient was given radiotherapy for brain tumour and also started on chemotherapy for breast carcinoma with brain metastasis. Since the entity of “Tumour-to-tumour Metastasis (TTM)” is uncommonly thought of and its detection is not easy, it is important that both clinicians and pathologists should adequately examine tissue samples of excised meningioma, as detecting the presence of any metastatic foci within the main mass will alter the prognosis and treatment plan considerably.
Kinematic Factors of Sitting Posture for Musculoskeletal Pain in University Staff
Authors: Perez Dhenyffer Bruna Almeida , Portela Bruno Sergio
Published: March 2024

Aims: The objective of the present study was to verify the relationship between musculoskeletal pain and kinematic factors of sitting posture in university staff at the University of Middle-West –UNICENTRO.
Methodology: The sample studied was 24 university agents from a total of 40 employees. Anthropometric data were collected by record and to assess the prevalence of pain, a standardized questionnaire was used. The employee positioning variables were: popliteal height, elbow-to-seat height, table height and thigh height. The arrangement of the workstation was also evaluated, checking the position of the computer and/or other equipment for daily use.
Results: It was found that 54.16% of the agents had some type of pain in the spine. The recommended chair seat for men would be a height of 44.3 cm and was found to be 50.2 cm, while for women the recommended height is 40.9 cm and was found to be 45.1 cm.
Conclusion: According to the results obtained, the height of the table was higher than recommended, which could perhaps justify the complaint of pain reported by university agents.
Assessing Tropospheric Ozone Influence on Garlic (Allium sativum L.) Rhizosphere Microbial Activity
Authors: JawaharJothi Gayathri , Kovilpillai Boomiraj , Mani Jayabalakrishnan Raja , Kannan Balaji , Selvaraj Selvakumar
Published: March 2024

The study conducted at the Climate Change Observatory, Woodhouse Farm, HRS, Ooty, during 2018-2019 focused on investigating the impact of ozone and ozone protectants on rhizosphere microbial activity in garlic cultivation. Specifically, the experiment evaluated the response of the commercial local variety Ooty-1 garlic to varying ozone levels and ozone protectants. Results from the study demonstrated notable variations in microbial activity, including bacteria, fungi, and actinomycetes, within the rhizosphere of garlic plants under different experimental conditions. Notably, the highest increase in bacterial activity was observed under ambient conditions with panchagavya spray, recording a significant log10 cfu/g of 8.9. Similarly, fungal and actinomycetes activity exhibited higher levels under ambient conditions, with respective log10 cfu/g values of 4.8 and 4.7. Conversely, elevated ozone levels at 150 ppb and 200 ppb led to a decline in bacterial, fungal, and actinomycetes activity within the rhizosphere. The reductions were substantial, with bacterial activity dropping to 2.5 log10 cfu/g and 1.9 log10 cfu/g, fungal activity to 1.1 log10 cfu/g and 0.9 log10 cfu/g, and actinomycetes activity to 2.4 log10 cfu/g and 2.1 log10 cfu/g at the respective ozone levels. However, the application of ozone protectants, including 3% panchagavya, 3% neem oil, and 0.1% ascorbic acid, demonstrated a mitigating effect on the negative impacts of tropospheric ozone on rhizosphere microbial diversity. This finding suggests that escalating concentrations of tropospheric ozone have a detrimental effect on the soil microbial activity of garlic. Still, the use of ozone protectants can significantly alleviate these effects by promoting microbial growth. Overall, the study underscores the importance of understanding the complex interactions between ozone levels, ozone protectants, and rhizosphere microbial activity in garlic cultivation, offering valuable insights for sustainable agricultural practices in the face of climate change challenges.
CmapTools: Integrating teaching, learning, and evaluation in online courses
Authors: Daley Barbara J. , Cañas Alberto J. , Stark‐Schweitzer Tracy
Published: March 2007

Concept maps are an instructional strategy that promotes meaningful learning. This chapter examines the use of concept maps in online environments through discussion of CmapTools software.
Learning object repositories
Authors: Lehman Rosemary
Published: March 2007

An erratum has been published for this article in New Directions in Adult and Continuing Education 114, Summer 2007 [].

This chapter looks at the development and nature of learning objects, meta‐tagging standards and taxonomies, learning object repositories, learning object repository characteristics, and types of learning object repositories, with type examples.
Effects of relative volatility ranking to the design of reactive distillation
Authors: Tung Shih‐Tse , Yu Cheng‐Ching
Published: March 2007

This work is aimed to provide a systematic design procedure to determine the process configuration, the relative position of the reactive zone, and separation sections. Instead of investigating real chemical systems, ideal chemical reaction systems with different relative volatility rankings will be studied. This provides a gradual transition as the reaction and separation properties change. The reaction considered is a reversible reaction, A + B ⇔︁ C + D, and this constitutes a quaternary system with 24 (4) possible relative volatility arrangements. These 24 systems can further be grouped into six categories according to the ranking of relative volatilities of reactants and products. The likely process configurations will be explored and design will be optimized based on the total annual cost (TAC). The results clearly indicate that the relative volatility rankings play a dominant role in the reactive distillation configuration and the TAC varies by a factor of ∼7 as we move from the most favorable case (reactants are intermediate keys) to the least favorable relative volatility ranking (products are intermediate keys). Finally, heuristics are given to correlate the relative volatility ranking to the TAC. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Recognition of DNA Three‐Way Junctions by Metallosupramolecular Cylinders: Gel Electrophoresis Studies
Authors: Malina Jaroslav , Hannon Michael J. , Brabec Viktor
Published: March 2007

The interaction of metallosupramolecular cylinders with DNA three‐way junctions has been studied by gel electrophoresis. A recent X‐ray crystal structure of a palindromic oligonucleotide forming part of a complex with such a cylinder revealed binding at the heart of a three‐way junction structure. The studies reported herein confirm that this is not solely an artefact of crystallisation and reveal that this is a potentially very powerful new mode of DNA recognition with wide scope. The cylinders are much more effective at stabilizing three‐way junctions than simple magnesium dications or organic or metallo‐organic tetracations, with the M cylinder enantiomer being more effective than P. The recognition is not restricted to three‐way junctions formed from palindromic DNA with a central AT step at the junction; non‐palindromic three‐way junctions and those with GC steps are also stabilised. The cylinder is also revealed to stabilise other Y‐shaped junctions, such as that formed at a fraying point in duplex DNA (for example, a replication fork), and other DNA three‐way junction structures, such as those containing unpaired nucleotides, perhaps by opening up this structure to access the central cavity.
The impact on survival of thromboembolic phenomena occurring before and during protocol chemotherapy in patients with advanced gastroesophageal adenocarcinoma
Authors: Tetzlaff Eric D. , Correa Arlene M. , Baker Jackie , Ensor Joe , Ajani Jaffer A.
Published: March 2007

BACKGROUND.

Thromboembolic events (TEEs) are considered common in patients with gastroesophageal carcinoma, but their frequency at baseline and during chemotherapy is not known. Because prophylactic anticoagulation results in improved overall survival (OS) of solid tumor patients, the authors hypothesized that TEEs at baseline and during chemotherapy would have an adverse effect on OS.

METHODS.

The authors analyzed patients with advanced gastroesophageal carcinoma who were treated on 4 prospective chemotherapy Phase II/III trials. Baseline and subsequent TEEs were documented and correlated with OS.

RESULTS.

On the 4 trials, 191 patients received single‐agent or a combination of a taxane, camptothecin, platinum, or fluoropyrimidine. At baseline, TEEs occurred in 5.3% of untreated patients compared with 8.5% of previously treated patients (who had received prior treatment for metastatic disease). The median OS was only 3.9 months for patients who had a TEE at any time versus 8.7 months for patients who never developed a TEE (P = .007). TEEs at baseline were correlated with poor median OS in untreated patients (4.9 months vs 8.9 months for patients without a TEE; P = .014). There was no associated between TEEs and the type of chemotherapy used.

CONCLUSIONS.

The current results established that TEEs at baseline and/or during chemotherapy are frequent and result in poor OS for patients with advanced gastroesophageal carcinoma. Aggressive methods to treat or prevent TEEs are warranted. Cancer 2007. © 2007 American Cancer Society.
Computation of one‐dimensional compressible flows including shocks
Authors: Thomas L. H.
Published: March 2007

The solutions of problems involving compressible flows have different functional forms in different regions, separated not only by discontinuities of the fluid itself but also by shock fronts and by characteristics starting from the origins of shock fronts and from points where such characteristics meet shocks. To obtain accuracy in numerical integration, small intervals and formulas using differences of low order are convenient immediately after crossing these lines, but much larger intervals, with differences of higher order, are sufficient elsewhere. The purpose of this paper is to explain a method of exploiting the economy made possible in this way.

If the equations for the one‐dimensional case are transformed to characteristic variables, they form a ‘canonical hyperbolic system’. Adams' method for ordinary differential equations extends to a variable interval by using divided differences of the derivative, and it then becomes practical to use it for starting and across discontinuities. Further, it applies directly to canonical hyperbolic systems. Numerical solution is then very direct over regions determined by two characteristics and is convenient where the flow crosses already existing shocks. Finally, the origin of a new shock in any interval can be detected and arrangements can be made for it.
Circumvention of Fluorophore Photobleaching in Fluorescence Fluctuation Experiments: a Beam Scanning Approach
Authors: Satsoura Dmitri , Leber Brian , Andrews David W. , Fradin Cécile
Published: March 2007

Photobleaching is a fluorophore‐damaging process that commonly afflicts single‐molecule fluorescence studies. It becomes an especially severe problem in fluorescence fluctuation experiments when studying slowly diffusing particles. One way to circumvent this problem is to use beam scanning to decrease the residence time of the fluorophores in the excitation volume. We report a systematic study of the effects of circular beam scanning on the photobleaching of fluorescent particles as observed in single‐photon excitation fluorescence fluctuation experiments. We start by deriving a simple expression relating the average detected fluorescence to the photobleaching cross section of the fluorophores. We then perform numerical calculations of the spatial distribution of fluorescent particles in order to understand under which conditions beam scanning can prevent the formation of a photobleaching hole. To support these predictions, we show experimental results obtained for large unilamellar vesicles containing a small amount of the fluorescent lipophilic tracer DiD. We establish the required scanning radius and frequency range in order to obtain sufficient reduction of the photobleaching effect for that system. From the detected increase in fluorescence upon increase in scanning speed, we estimate the photobleaching cross section of DiD.
Osmium(II) and Osmium(IV) Complexes with Phosphane–Ethers, –Esters, and –Amines as Mono‐ and Bidentate Ligands
Authors: Weber Birgit , Werner Helmut
Published: March 2007

The six‐coordinate dihydridoosmium(IV) complex [OsH2Cl2(PiPr3)2] (1) reacted with the hemilabile chelating phosphanes iPr2PCH2CH2OMe and iPr2PCH2CO2R (R = Me, Et) at room temperature to give the substitution products [OsH2Cl2(iPr2PCH2CH2OMe)2] (2) and [OsH2Cl2{κ2(P,O)‐iPr2PCH2C(=O)OR}{κ(P)‐iPr2PCH2CO2R}] (3, 4) in good to excellent yields. Treatment of 1 with iPr2PCH2CH2NMe2 led to the displacement of only one PiPr3 ligand and gave [OsH2Cl2(PiPr3)(iPr2PCH2CH2NMe2)] (5). The reaction of 1 with iPr2PCH2CH2OMe and iPr2PCH2CO2R (R = Me, Et) at elevated temperature afforded the osmium(II) complexes [OsCl2{κ2(P,O)‐iPr2PCH2CH2OMe}2] (6) and [OsCl2{κ2(P,O)‐iPr2PCH2C(=O)OR}2] (7, 8), which were also obtained on heating the osmium(IV) precursor 3 or the labile 1:1 adducts of 3 and 4 with ethene in benzene under reflux. The dihydrido compounds 2 and 3 reacted with CO at room temperature to give initially the octahedral all‐cis‐configured complexes [OsCl2(CO)2{κ(P)‐iPr2PCH2CH2OMe}2] (11a) and [OsCl2(CO)2{κ(P)‐iPr2PCH2CO2Me}2] (12a), which rearrange to the more stable cis,cis,trans isomers 11b and 12b in benzene under reflux. The all‐trans isomer 11c and themonocarbonyl complexes trans,trans‐[OsCl2(CO){κ2(P,O)‐iPr2PCH2C(=O)OR}{κ(P)‐iPr2PCH2CO2R}] (13, 14) were prepared by passing CO through a solution of 6–8 in benzene or toluene/dichloromethane at room temperature. While the osmium(IV) compounds 3, 4 as well as the osmium(II) complexes 7, 8 reacted with CNtBu to give the neutral complexes cis,cis,trans‐[OsCl2(CNtBu)2{κ(P)‐iPr2PCH2CO2R}2] (15, 16), treatment of 5 with CNtBu afforded the ionic product [OsHCl(CNtBu)2(PiPr3)(iPr2PCH2CH2NHMe2)]Cl (17). The reaction of 7 with Ph2CN2 did not lead to the formation of a (carbene)osmium(II) compound but gave the dinitrogen complex trans,trans‐[OsCl2(N2){κ2(P,O)‐iPr2PCH2C(=O)OMe}(κ(P)‐iPr2PCH2CO2Me)] (18) instead. The structurally related vinylidene complexes trans,trans‐[OsCl2(=C=CHPh){κ2(P,O)‐iPr2PCH2CH2OMe}{κ(P)‐iPr2PCH2CH2OMe}] (19a) andtrans,trans‐[OsCl2(=C=CHPh){κ2(P,O)‐iPr2PCH2C(=O)OR}{κ(P)‐iPr2PCH2CO2R}] (20, 21) were prepared from 6–8 and PhC≡CH as starting materials. The cis,cis‐configuredcompound [OsCl2(=C=CHPh)(PiPr3){κ2(P,N)‐iPr2PCH2CH2NMe2}] (22) was obtained analogously from 5 and phenylacetylene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Small Molecular Chromogenic Sensors for Hg2+: A Strong “Push‐Pull” System Exists after Binding
Authors: Fu Yanyan , Li Hongxiang , Hu Wenping
Published: March 2007

Two small molecular chromogenic sensors 1 and 2 for detection of Hg2+ are described. After coordination with Hg2+, a red shift of about 100 nm was observed in the UV/Vis spectra and the color of the solution changed from pale yellow to red which could easily be detected by the naked eye. The results indicate a strong push‐pull system was formed after coordination of Hg2+. The 1H NMR spectra and control experiments showed the binding sites of 1 and 2 to be the aniline groups rather than the azine bridge. Moreover, mercury test papers were made by adsorbing 1 onto filter paper, allowing heterogeneous sensing of Hg2+ in aqueous solution.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A Dispersion Modeling Study of Major VOCs from Non‐Point Emission Sources in the Urban Atmosphere
Authors: Kim M.‐S. , Kim J. H. , Park H.‐S. , Sun Y. S. , Yi J.
Published: March 2007

To assist with the understanding and solving of toxic air pollutant problems in urban areas, an atmospheric dispersion model, SKYDM, was developed with three preprocessors (meteorology, emission, and topography), and a physical process and chemical decay term based on NOx‐O3‐RH photochemistry in the actual atmosphere. SKYDM can work with multicomponents in a single model run, as well as with a single compound in a model run and produces 2D meteorological field results due to an integration approach. The present study aims to develop and evaluate a SKYDM at local spatial scales, in the short term. A comparative study is conducted to estimate the effects of model parameters in defining the applicability limits of dispersion models and to examine the integration approach methodology. All simulations are run for volatile organic compounds (VOCs) such as BTXS (Benzene, Toluene, Xylene, and Styrene) emitted from non‐point sources, located at 151 villages in seven divisions, in a northeastern portion of Seoul, Korea, with eight different meteorological data sets during 2002. Modeled toluene concentrations are compared with those observed at ten monitoring sites. The main findings of the present study are as follows: (a) Model uncertainties are obviously caused by limitations of meteorological conditions and emission and topographical information, by removal processes, and by user errors or application skills – the chemical decay term was a comparatively significant parameter in the removal of toxic air pollutants, (b) the integration approach indicated a correlation between observations and the model, and (c) the SKYDM showed potential as a useful tool for assessing the air quality in urban areas. In further work, the SKYDM will be upgraded to an improving model algorithm with fully detailed input information, and evaluated in comparison with other Gaussian dispersion models.
Microbial Resource Management: The Road To Go for Environmental Biotechnology
Authors: Verstraete W. , Wittebolle L. , Heylen K. , Vanparys B. , de Vos P. , van de Wiele T. , Boon N.
Published: March 2007

The breakthroughs in microbiology have allowed us to come to terms with the microbial resources present in culture collections and in natural environments. The challenge at present is to manage these microbial resources, particularly when one deals with open systems where the dynamics of microbial ecology are predominant. Hence, to properly address the aspects of Microbial Resource Management (MRM), one needs to handle the questions of who is there, who is doing what with whom and how can one adjust, control and/or steer these mixed cultures and communities. It is argued that microbial ecologists and environmental microbiologists need to address a new mind‐set. The Beijerinck axioma that all microorganisms are everywhere should not be presumed to be generally valid. The Darwin based niche assembly concept needs to be supplemented with the neutral theory of Hubbell. The Pareto 80/20 principle is also applicable to the macro‐economies of microbial communities. Finally, the concept of a “stable” microbial community should be replaced by that of a cooperative community continuum. Overall, MRM is at the basis of a number of new developments in domains such as environmental safety and health, renewable energy production, closing environmental cycles and providing new materials. Specific examples such as, for example, pro‐active immuno‐stimulation by means of drinking water, electro‐microbiology, decreasing global warming by implementation of methanotrophs and generation of nano‐biocatalysts are discussed.
Comparison of the Adsorption Capabilities of Myriophyllum spicatum and Ceratophyllum demersum for Zinc, Copper and Lead
Authors: Keskinkan O. , Goksu M. Z. L. , Yuceer A. , Basibuyuk M.
Published: March 2007

Industrial wastewaters contain various heavy metal components and therefore threaten aquatic bodies. Heavy metals can be adsorbed by living or non‐living biomass. Submerged aquatic plants can be used for the removal of heavy metals. This paper exhibits the comparison of the adsorption properties of two aquatic plants Myriophyllum spicatum and Ceratophyllum demersum for lead, zinc, and copper. The data obtained from batch studies conformed well to the Langmuir Model. Maximum adsorption capacities (qmax) were obtained for both plant species and each metal. The maximum adsorption capacities (qmax) achieved with M. spicatum were 10.37 mg/g for Cu2+, and 15.59 mg/g for Zn2+ as well as 46.49 mg/g for Pb2+ and with C. demersum they were 6.17 mg/g for Cu2+, 13.98 mg/g for Zn2+ and 44.8 mg/g for Pb2+. It was found that M. spicatum has a better adsorption capacity than C. demersum for each metal tested. Gibbs free energy and the specific surface area based on the qmax values were also determined for each metal.
Development of ELISA for the Determination of Transgenic Bt‐Cottons Using Antibodies against Cry1Ac Protein from Bacillus thuringiensis HD‐73
Authors: Wang S. , Guo A. Y. , Zheng W. J. , Zhang Y. , Qiao H. , Kennedy I. R.
Published: March 2007

The area cultivated with Bt‐cottons expressing Cry1Ac gene increases year by year in China and other countries. To evaluate any potential adverse impacts on the environment from the release of Bt (Bacillus thuringiensis) technology, the development of a method for easily detecting the activity of the Cry1Ac toxins is of particular interest. The aim of this study was to develop sandwich‐ELISA for the detection of Cry1Ac protein in Bt‐cotton tissues. A specific antibody was obtained from rabbits inoculated with Cry1Ac protein derived from Bt strain HD‐73 and a secondary antibody conjugated to HRP could combine the Bt Cry1Ac protein specifically. The limit of detection was 5 ng/mL and there were no cross‐reactions between the positive control of Cry1Ab/1Ac, Cry1C, Cry2A, Cry3Bb1 and Cry9C. Extracts of proteins from cotton leaves were used to evaluate the suitability of the assay. Tris‐borate buffer and sodium carbonate buffer were employed for the extraction of protein, the limit absorbance of detection was 0.134 and 0.449, respectively, and the latter produced a higher background. The results showed that cultivars GK‐12, GK‐22, insect‐resistant cotton, bivalent transgenic cotton and shiyuan 321 assayed positively and NON was the negative sample. The PCR method was used for the validation of the developed assay. Although both methods allowed the same results to be obtained, ELISA needed simple equipment and took less time. The developed immunoassay method is considered reliable for the detection of Bt Cry1Ac protein.
A Microbiological Test Method to Determine the Cleanability of Filter Media in Solid‐Liquid‐Separation Applications
Authors: Stahl S. , Siggelkow S. , Nirschl H.
Published: March 2007

One of the major properties in the design and development of filter media for the food and drug industry is their cleanability. They should be designed according to hygienic criteria thereby decreasing residuals and reducing cleaning time and costs. A reproducible test method is necessary to determine or validate the degree of cleanability of filter media and to indicate areas of poor hygienic design. This work focused on the development of such a filter test and provides information about impurity, whether it occurs or not, and its local resolution. The growth of a microorganism, which is introduced as impurity, is used for the detection of residues which grow to the surface of the sample and offer a 2‐dimensional analysis. With this approach, different kinds of filter media can be compared with each other regarding their cleanability.
Floor response spectrum method for seismic analysis of multiply supported secondary systems
Authors: Asfura Alejandro , Kiureghian Armen Der
Published: March 2007

Fundamental principles from structural dynamics, theory of random processes and perturbation techniques are used to develop a new method for seismic analysis of multiply supported secondary subsystems, such as piping attached to primary structures. The method provides a decoupled analysis of the secondary subsystem wherein the response is given in terms of response spectra associated with the attachment points (‘floors’). In order to account for correlations between modal responses and between support motions, an extension of the conventional floor response spectrum, denoted crossoscillator, cross‐floor response spectrum, is introduced. Important effects of tuning, interaction, non‐classical damping and spatial coupling, which are inherent characteristics of combined primary–secondary systems, are included through the extended spectra. An efficient method for generation of the extended spectra directly in terms of a ground response spectrum is developed.

Numerical comparisons with exact results are used to examine the accuracy of the proposed method and to demonstrate the importance of the characteristics mentioned above. In all cases examined, the proposed method shows excellent agreement with exact results. By accounting for the effect of interaction, the proposed method leads to more realistic and economical design criteria for secondary subsystems.
Study of the earthquake response of pine flat dam
Authors: Hall John F.
Published: March 2007

The earthquake response of Pine Flat Dam is examined by a study of time history responses computed for a large set of earthquake ground acceleration records whose time axes have been systematically varied. Linear elastic behaviour is assumed. Topics considered include an investigation of the importance of the presence of water, water compressibility and the vertical component of ground motion; an evaluation of the accuracy of the lumped, added mass representation of the water; and a determination of the intensity of earthquake required to initiate non‐linear behaviour in both the dam and water.
Use of statistical data in assessing local seismicity
Authors: Rosenblueth Emilio
Published: March 2007

Local seismicity is a probabilistic description of earthquake generation in a region. Here we begin by defining the shape of the curve of exceedance rate vs. magnitude on the assumption that earthquake generation is a Poisson process. Probability distributions are assigned to the parameters of the curve, based on geotectonic information. Then statistical data are incorporated using Bayes' theorem. Posterior distributions are improved through use of data from tectonically similar regions.
Analysis of the observed seismic response of a highway bridge
Authors: Wilson John C.
Published: March 2007

Strong‐motion accelerograms obtained on the San Juan Bautista 156/101 Separation Bridge during the 6 August 1979 Coyote Lake, California, earthquake are used to examine the response of this multiple‐span bridge to moderate levels of earthquake loading. Although the bridge was not damaged, the records are of significant engineering interest as they are the first to be recorded on a highway bridge structure in North America. A technique of system identification is used to determine optimal modal parameters for linear models which can closely replicate the observed time‐domain seismic response of the bridge. Time variations in frequency and damping in the horizontal response are identified using a moving‐window analysis. A three‐dimensional finite element model is developed to study the bridge response in detail. The first two horizontal modal frequencies computed from this model are in excellent agreement with information obtained during the system identification analysis provided the finite element model's expansion joints are locked, preventing relative translational motions from occurring across the joints. Locking is confirmed by the observed seismic deformations of the structure in the fundamental mode. Fundamental vertical frequencies of the individual spans, predicted by the finite element model, are in very good agreement with ambient vibration test data.
Axisymmetric soil–structure interaction by global–local finite elements
Authors: Avanessian V. , Muki R. , Dong S. B.
Published: March 2007

A version of the global–local finite element method is presented for studying dynamic steady‐state soil–structure interaction wherein the soil medium extends to infinity. Herein, only axisymmetric behaviour is considered. In this approach, conventional finite elements are used to model the structure and some portion of the surrounding soil medium considered to be homogeneous and isotropic. A complete set of outgoing waves in the form of spherical harmonics for the entire space is used to represent the behaviour in the half‐space beyond the finite element mesh and these are termed the global functions. Full traction and displacement continuity is enforced at the finite element mesh interface with the outer region. On the free surface of the half‐space in the outer field, traction‐free surface conditions are enforced by demanding that a sequence of integrals of the weighted‐average tractions must vanish. Numerical examples are presented for the response of different shaped foundations, resting on the free surface or at various submerged levels, due to a normal seismic plane compressional wave. Plots of differential scattering cross‐sections show the angular distribution of the energy (its directional nature) of the scattered field.
Effective eccentricity for inelastic seismic response of buildings
Authors: Tso W. K. , Bozorgnia Y.
Published: March 2007

The concept of effective eccentricity is generalized for inelastic systems to provide guidelines for estimating the maximum dynamic edge displacement and resisting element deformation of a single mass monosymmetrical system subjected to unidirectional ground excitations. Inelastic responses of three structural models having the same overall elastic responses are compared and the model which generally results in larger edge displacement is chosen as the structural model to be used to evaluate the effect of asymmetry. The inelastic effective eccentricity is calculated for different values of the system parameters, based on an ensemble of six ground motion records as input. It is concluded that, except for stiff structures having low yield strength, the elastic effective eccentricity curves developed previously by Dempsey and Tso can provide a reasonable or relatively conservative estimate for inelastic effective eccentricity, and these curves can be used to estimate the edge displacement and element deformation of inelastic eccentric systems.
Dynamic response of framed structures
Authors: Dyrbye Claës
Published: March 2007

A method for analysing plane frames subjected to dynamic forces or to ground motion is presented and illustrated by a numerical example. Numerical integration uses the approximation of constant acceleration in each time interval, as in Newmark's β‐method with β = 1/4. In space, calculations are carried out storey by storey, as in Holzer's or Myklestad's methods in the case of harmonic vibrations.
Effect of vertical motion on friction‐driven isolation systems
Authors: Lin B. C. , Tadjbakhsh I.
Published: March 2007

The effect of the vertical component of ground motion on the horizontal response of a sliding system is studied. Soil–foundation interaction is included. The results indicate that the effect of vertical motion is significant in the cascs of harmonically excited foundations.
Influence of different sites on seismic base shear of buildings
Authors: Balendra Thambirajah , Heidebrecht Arthur C.
Published: March 2007

In this paper, a statistical study based on thirty‐two strong rock motions is presented for the dynamic base shear of buildings on three different sites representing stiff soil, deep cohesionless soil and soft clay conditions. A short and squatty building and a tall and slender building are selected. For each building height, frame, wall and shearwall–frame systems are considered. It is found that short and squatty frame systems have the largest base shear. As for buildings on rock, the response of buildings on stiff and deep cohesionless soil conditions depends on the peak horizontal acceleration and peak horizontal velocity of the rock motion. Furthermore, the soil–structure interaction which affects only the stiff structures is found to reduce the dynamic base shear.
Approximate dynamic model of embedded foundation in time domain
Authors: Wolf John P. , Somaini Dario R.
Published: March 2007

A discrete model to represent the unbounded soil (halfspace) in a soil–structure interaction analysis in the time domain is developed. For each dynamic degree of freedom of the foundation node, the discrete model consists of a mass M0 which is attached to a rigid support with a spring K and with a damper C0. In addition, a free node with the mass M1 is introduced, which is connected to the foundation node with a damper C1. All coefficients are frequency‐independent. The discrete model is semi‐empirical. It is based on a semi‐infinite truncated cone, whereby, after enforcing the static stiffness, the remaining parameters are modified to achieve an optimal fit of the dynamic‐stiffness coefficient in the frequency domain.

The spring K is equal to the static stiffness. The coefficients appearing in the equations for the dampers C0, C1 and the masses M0, M1 are specified (assuming a homogeneous halfspace) for the disc, the embedded cylinder, the rectangle (also embedded) and the strip. A square on a layer whose stiffness increases with depth resting on a homogeneous halfspace is also treated. For an embedded foundation, eccentricities arise. Material damping increases the damper C0 and the mass M0.
Experimental evaluation of changes of dynamic properties of buildings on different grounds
Authors: Maciag Edward
Published: March 2007

The paper presents an experimental evaluation of changes of dynamic properties (periods of natural vibrations and damping) of three identical precast concrete panel buildings of S storeys and a basement resting on different grounds. Building vibrations were excited by firing of explosives in a quarry. On the basis of the investigations, it may be said that a change of flexibility of the foundation medium under the same low buildings distinctly influences the change of the first natural periods (in two mutually perpendicular directions parallel to the longitudinal and transverse axes) of the buildings.
Transient elastodynamic analysis of three‐dimensional problems by boundary element method
Authors: Banerjee Prasanta K. , Ahmad Shahid , Manolis George D.
Published: March 2007

An advanced implementation of the direct boundary element method applicable to transient problems involving three‐dimensional solids of arbitrary shape and connectivity is presented. The work first focuses on the formulation of the method, followed by a discussion of the fundamental singular solutions. Subsequently, a family of isoparametric boundary elements is introduced, along with the necessary numerical integration techniques as well as the solution algorithm. Numerical examples are presented, which demonstrate the unconditional stability and high accuracy of this dynamic analysis technique.
Dynamic stability of liquid‐filled cylindrical shells under vertical excitation, Part I: Experimental results
Authors: Chiba M. , Tani J. , Yamaki N.
Published: March 2007

Experimental studies have been carried out on the dynamic stability of a cantilever cylindrical shell partially filled with liquid, under vertical excitation. Two polyester test cylinders with radius 100 mm, thickness 0.25 mm, and lengths 113 and 227 mm were used. The test cylinder was harmonically excited with constant acceleration‐ or displacement‐amplitude. It was found that not only the parametric principal instability resonance but also the parametric combination involving two natural vibrations, each of which has the same circumferential wave number but different axial mode numbers, could occur. The latter type of vibration apparently has not been previously studied. By varying the dimensionless water height from 0.25 to 1.0 stepwise by 0.25 increments, the instability regions and vibration modes were determined for the two test cylinders. The response waves of shell wall and liquid free surface, and axial and circumferential vibration modes were also observed.
Multiply supported secondary systems part I: Response spectrum analysis
Authors: Burdisso R. A. , Singh M. P.
Published: March 2007

A response spectrum procedure is developed for seismic analysis of multiply supported secondary systems. The formulation is based on the random vibration analysis of structural systems subjected to correlated inputs applied at several supports. For a proper response spectrum analysis of a multiple support system, the support inputs are required to be defined in terms of the auto and cross pseudo‐acceleration and relative velocity floor response spectra. Also information about the floor displacements and velocities as well as their correlations is required. The response of the secondary system is expressed as a combination of the dynamic and pseudo‐static response components. The dynamic component is associated with the inertial effects of the support accelerations, whereas the pseudo‐static component is due to the displacement of the supports relative to each other. Herein, the correlation between these two parts of the response is included through a term called the cross response component. Each of these components of the response can be calculated by a response spectrum method. The application of the proposed method is demonstrated by numerical examples.
Multiply supported secondary systems part II: Seismic inputs
Authors: Singh M. P. , Burdisso R. A.
Published: March 2007

For proper seismic analysis of secondary systems with multiple supports, the prescription of the seismic input in terms of the conventional pseudo‐acceleration floor response spectra is quite inadequate. It is necessary that the relative velocity floor response spectra as well as the cross floor response spectra, characterizing the correlation between the motions of various floors where the secondary system is attached, be also prescribed as the inputs. In addition to these, it is also necessary to define the floor displacements, velocities and their correlations. In this paper, the methods which can use the ground response spectra directly to obtain these inputs are developed. These methods are based on the random vibration analysis of the supporting primary structure, but still do not require the base input in stochastic form; conventional ground response spectra can be directly used. Numerical results demonstrating the application of the approaches are given.
Inelastic earthquake spectra
Authors: Elghadamsi F. E. , Mohraz B.
Published: March 2007

This paper presents a procedure for computing inelastic design spectra in terms of yield displacement. The procedure results in substantial computational savings as compared to the current procedures for computing the inelastic spectra in terms of displacement ductility. The proposed method is used to obtain inelastic design spectra for alluvium and rock. The results for alluvium are compared to those from the Newmark and Hall,10 Riddell and Newmark12 and Lai and Biggs4 studies. The findings indicate that for given ductility and frequency one may de‐amplify the elastic response or reduce the elastic forces more for a structure on rock than for a structure on alluvium.

A technique is presented so that the inelastic design spectrum can be scaled to any desired yield displacement and acceleration. An example is presented to illustrate how the proposed inelastic spectra can be used to compute the required ductility for a given system.
An evaluation of strong motion records and a new parameter A95
Authors: Sarma S. K. , Yang K. S.
Published: March 2007

From the past studies of acceleration records, it is generally recognised that peak acceleration is not a suitable measure of the ground motion for design purposes. Usually, peak accelerations are difficult to predict. They occur in high frequency pulses containing very little energy and therefore are of little consequence. On the other hand acceleration has direct and useful application in engineering design.

A new parameter A95 is introduced in this paper which is defined as that level of acceleration which contains up to 95 per cent of the Arias Intensity. From the study of 135 records, it is noticed that the variation of the fraction of Arias Intensity with acceleration level can be described by a very well defined relationship. It is also observed that A95 and Arias Intensity bear a stable relationship. Furthermore, the Arias Intensity at a site correlates more closely with the earthquake magnitude and the distance of the site from the source in attenuation relationships. From the available data, relationships are derived which show that there is a difference between the near‐field and the far‐field attenuation laws.

The following relationships are obtained:
equation image
where Es = Arias Intensity, Ex = fraction of Arias Intensity above an acceleration level A, M = surface wave magnitude, R = nearest distance to the energy source or focal distance in km.
Exact dynamic member stiffnesses for a beam on an elastic foundation
Authors: Williams F. W. , Kennedy D.
Published: March 2007

This paper gives exact Bernoulli–Euler dynamic flexural member equations for a uniform beam on an elastic foundation. These enable exact results to be obtained when the beam is included in free or sinusoidally forced vibration calculations for a plane or space frame, at any frequency. In addition, information is presented to ensure that no natural frequencies are missed in a free vibration analysis.
The saros–marmara earthquake of 9 August 1912
Authors: Ambraseys N. N. , Finkel C. F.
Published: March 2007

This paper examines one of the largest earthquakes in the Balkans in this century which remains hitherto imperfectly known and in need of evaluation. It shows that, given certain conditions, it is perfectly feasible to study in detail an earthquake that occurred three‐quarters of a century ago. This earthquake destroyed more than 300 villages and towns, killing over 2,000 people just north of the Dardanelles. The earthquake, which had a magnitude of M = 7.4, was associated with an oblique, 50 km long fault‐break, and with the liquefaction of river deposits at large epicentral distances. Landslides and fire added to the damage which can be expressed in terms of a damage ratio that in turn allows the establishment of a loss–intensity relationship. The results may be used to estimate losses to houses of similar type due to future earthquakes.
Seismic response of foundations embedded in a layered half‐space
Authors: Luco J. E. , Wong H. L.
Published: March 2007

An integral equation technique to determine the response of foundations embedded in a layered viscoelastic half‐space when subjected to various types of seismic waves is presented. The technique is validated by comparison with previous results for rigid hemispherical and cylindrical foundations embedded in a uniform half‐space. Illustrative results for rigid cylindrical foundations embedded in layered media are also presented.
Torsional vibrations of elastic foundations embedded in an elastic half‐space
Authors: Rajapakse R. K. N. D. , Shah A. H. , Datta S. K.
Published: March 2007

This paper examines the axisymmetric torsional vibrations of an elastic pile and a hemispherical foundation embedded in a homogeneous elastic half‐space. The embedded foundation–half‐space system is decomposed into an extended half‐space and a fictitious foundation. The deformations of the fictitious system are specified by an admissible function containing a set of generalized coordinates. The Lagrangian equations of motion are used to determine these coordinates associated with the assumed displacement function. Numerical results are presented for torsional impedance of an elastic pile and a hemisphere to illustrate the effects of relative flexibility and geometry. By employing certain simplifications on the pile–half‐space system an approximate closed form solution is presented for the torsional impedance of an elastic pile.
Two‐dimensional effective stress analysis of liquefaction of irregular ground including soil–structure interaction
Authors: Ohtsuki Akira , Itoh Tetsuji
Published: March 2007

An effective stress method is presented for analysis of seismic response and liquefaction of irregular ground including soil–structure interaction, based on an implicit–explicit finite element method. A pore water pressure is computed with iteration from the total stress considering an undrained condition. The simulated pore water pressure is in reasonably good agreement with the experimental data. The proposed method of analysis is compared with other well‐known methods for a one‐dimensional model, which is in good agreement. The present effective stress method is also applied to liquefaction problems involving a two‐dimensional soil–structure model. The structure is modelled by not only a rigid model but also as a multi‐degree‐of‐freedom system with bi‐linear springs. The numerical results are considered to be significant from the viewpoint of earthquake engineering.
A technique for the analysis of the response of dams to earthquakes
Authors: Lotfi Vahid , Roesset Jose M. , Tassoulas John L.
Published: March 2007

A finite element technique is developed for two‐dimensional problems of dynamics of dam–water–foundation systems taking into account all interactions rigorously. Water–foundation interaction, which previous developments have only simulated, is considered by imposing proper conditions at the fluid–solid interface. Furthermore, the technique permits treatment of layered foundations. An application to a concrete gravity dam–water–foundation system is presented and discussed.
Evaluation of code torsional provisions by a time history approach
Authors: Chandler A. M. , Hutchinson G. L.
Published: March 2007

Presented in this paper is a detailed parametric study of the coupled lateral and torsional response of single‐storey building models subjected to earthquake base loadings. The aim is to assess the influence of torsional coupling on the elastic responses of buildings subjected to transient ground motion records, and to make comparisons with current code provisions which make allowance for coupling effects by means of empirical design procedures. The study of building responses to selected earthquake excitations shows that the qualitative effects of the controlling parameters on the maximum translational and torsional responses of the coupled system are similar to those observed in analyses using idealized response spectra to represent the input ground motion. It is also demonstrated that for particular ranges of the key parameters defining the structural system, typical of the properties of many actual buildings, torsional coupling induces significant amplification of earthquake forces. This amplification is shown to be inadequately accounted for in the current design provisions of major building codes. Recommendations for improving existing design practice for asymmetric structures are outlined.