bluuebunny/crossref_metadata_2025 huggingface dataset:
The effectiveness of trenches in reducing seismic motion
Authors: May Thomas W. , Bolt Bruce A.
Published: March 2007

The effect of placing barriers in the travel path of P, SV and SH seismic waves has been studied using time‐domain solutions of plane‐strain finite element programs for two‐dimensional crustal models. The wavefields considered propagate parallel to the free surface of an elastic medium consisting of a single layer over a halfspace. Barriers take the form of open‐air trenches. Effects of damping are assessed by considering representative viscoelastic conditions. Computations are presented as the ratio of spectral energy observed at a point with the barrier system in place in the model to the spectral energy observed at the same point without the barrier system in the model. These spectral ratios are dependent upon the direction of wave propagation.

The calculations brought to light the marked role of surficial layering and attenuation properties of the surface rocks or soils on the effectiveness of seismic trench barriers. Barrier models without these features cannot in general reliably predict seismic wavefields at the surface. In the range of cases studied, trench depth d rather than width is the most sensitive parameter. When the ratio d/λ, the ratio of trench depth to the wavelength of shear waves, is greater than about 0·6, power spectral ratios of 0·06 and less are found for SH waves and the vertical component of SV motion for frequencies of 4–6 Hz. By contrast, for frequencies less than 3–4 Hz, power spectral ratios from unity to about two and greater are observed, indicating amplification for the horizontal component of wave motion. Spectral ratios calculated at some locations in front of the barrier system show over two‐fold amplification. Spectral ratios also change significantly with the relative location of the free surface observation point.
Incremental time—space finite strip method for non‐linear structural vibrations
Authors: Cheung Y. K. , Lau S. L.
Published: March 2007

Based on an incremental Hamilton's principle a versatile and systematic computer method for analysing non‐linear structural vibrations is developed in this paper. The essence of the proposed method can be regarded as an incremental harmonic balance method associated with a finite strip procedure in the time‐space domain. Only linearized equations in terms of frequency increment, amplitude increments, etc. have to be formulated and solved in each incremental step. This method is applicable to highly non‐linear problems and may be generalized to related non‐linear periodic structural motions such as dynamic stability, flutter and some motions of a rotating body, etc. To show the effectiveness and versatility of this method, a typical time‐space finite strip for beam problems is worked out and examples for a wide variety of vibration problems including free and forced vibrations, super‐ and sub‐harmonic resonances, and complicated phenomena such as internal resonance are computed. Comparisons with previous results are also made.
Non‐linear seismic response of arch dams
Authors: Niwa Akira , Clough Ray W.
Published: March 2007

An experimental study of non‐linear mechanisms that may occur during intense seismic response of arch dams is described in this paper. The presentation deals with three types of non‐linearity that were observed during shaking table model studies: monolith joint opening, cantilever cracking, and reservoir cavitation at the dam face.

The monolith joint opening phenomenon was represented by a segmental arch ring model that simulated a horizontal slice of a prototype dam. The cantilever cracking and reservoir cavitation mechanisms were studied using a model gravity dam section. The principal conclusion of the investigation was that shaking table experiments provide a practical means of studying the non‐linear earthquake response of concrete arch dams, including their actual failure mechanisms.
Two‐dimensional dynamic analysis of concrete gravity and embankment dams including hydrodynamic effects
Authors: Hall John F. , Chopra Anil K.
Published: March 2007

An analysis procedure in the frequency domain is developed for determining the earthquake response of two‐dimensional concrete gravity and embankment dams including hydrodynamic effects; responses of the elastic dams and compressible water are assumed linear. The dam and fluid domain are treated as substructures and modelled with finite elements. The only geometric restriction is that an infinite fluid domain must maintain a constant depth beyond some point in the upstream direction. For such an infinite uniform region, a finite element discretization over the depth is combined with a continuum representation in the upstream direction. The fluid domain model approximately accounts for interaction between the fluid and underlying foundation medium through a damping boundary condition applied along the reservoir bottom, while the dam foundation is assumed rigid. Several examples are presented to demonstrate the accuracy of the fluid domain model and to illustrate dam responses obtained from the analysis procedure.
The response of veterans hospital building 41 in the San Fernando earthquake
Authors: Rutenberg Avigdor , Jennings Paul C. , Housner George W.
Published: March 2007

During the 9 February, 1971 San Fernando earthquake, Building 41 of the Veterans Administration Hospital was in an area of very strong snaking; being directly over a portion of the causative fault; it is estimated that the building experienced a maximum base shear of 60 to 130 per cent of the weight of the structure. It survived with very minor structural damage, although designed with a lateral force coefficient of only 10 per cent. The study attempts to reconcile these facts by analysis of the transverse response of the building. A code‐oriented, lateral force analysis is only partially successful in this reconciliation in that it indicates first yield at lateral loads of 15–20 per cent of the weight of the structure, with a capacity of 35–45 per cent if redistribution of loads among the walls is permitted. The capacity against static overturning is 45–50 per cent. A dynamic analysis of a fixed‐base three‐dimensional linear model of the structure gives essentially the same results. A third study of a two‐dimensional, dynamic model incorporating partial uplift and soil yielding indicates that the successful response of the building is attributable to the large strength built into the structure and the beneficial effects of non‐linear soil‐structure interaction.
Optimum absorber parameters for various combinations of response and excitation parameters
Authors: Warburton G. B.
Published: March 2007

In recent papers the author has shown that when determining optimum parameters for an absorber which minimizes the vibration response of a complex system, the latter may be treated as an equivalent single degree‐of‐freedom system if its natural frequencies are well separated. Emphasis was on minimizing the displacement response when the excitation was a harmonic force. In the present paper simple expressions for optimum absorber parameters are derived for undamped one degree‐of‐freedom main systems for harmonic and white noise random excitations with force and frame acceleration as input and minimization of various response parameters. These expressions can be used to obtain optimum parameters for absorbers attached to complex systems provided that optimization is with respect to an absolute, rather than a relative, quantity. The requirement that the natural frequencies should be well separated is investigated numerically for the different cases. The effect of damping in the main system on optimum absorber parameters is investigated also.
Vibration tests on emosson arch dam, Switzerland
Authors: Deinum P. J. , Dungar R. , Ellis B. R. , Jeary A. P. , Reed G. A. L. , Severn R. T.
Published: March 2007

Measurements have been made of vibrations induced in the 180 m high Emosson arch dam in Switzerland3 by a system of mechanical eccentric‐mass vibrators and by the natural wind. Details are given of the dam itself, the tests and the experimental results obtained. Finite element calculations made before the tests, which include reservoir and foundation effects, are compared with the measurements.
Seismic design of flexible cylindrical liquid storage tanks
Authors: Balendra T. , Ang K. K. , Paramasivam P. , Lee S. L.
Published: March 2007

Seismic response of cylindrical storage tanks anchored to rigid base slabs is considered. Finite elements are used for the liquid and tank wall, idealized as a thin shell. For steel tanks of practical dimensions, design charts are presented for natural frequencies, maximum shear and overturning moment on the foundation, and maximum stress resultants in the tank wall. Furthermore, an analytical expression for the superelevation of the free surface is presented.
Arma models for earthquake ground motions
Authors: Chang Mark K. , Kwiatkowski Jan W. , Nau Robert F. , Oliver Robert M. , Pister Karl S.
Published: March 2007

This paper outlines the use of discrete, autoregressive/moving‐average (ARMA) models for identification and estimation of parameters in models derived from analysis of uniformly digitized earthquake ground motion acceleration data. Such models are of equal generality as compared to continuous‐time models and have a number of significant advantages for purposes of digital analysis and simulation. The structure of ARMA models is briefly described, their relation to continuous models noted, and results of their application to a number of recorded accelerograms summarized.
Frequency domain analysis of time integration operators
Authors: Preumont A.
Published: March 2007

The present paper analyses the error associated with the time integration operators in structural dynamics. It considers the time integration operators as digital recursive filters. The transfer functions of the discretized equations are derived and compared with the transfer function of the differential equation. This leads to a new approach for the accuracy analysis of the time integration operators, which is not restricted to the homogeneous part of the discretized equation. It can therefore be applied to the Duhamel Integral for which, as far as the author is aware, no error analysis has been reported so far. Results are presented for the Newmark's family integration operators. Various assumptions on the variation of the excitation between the sampling points in the Duhamel Integral are also analysed.
Phase properties of a class of random processes
Authors: Nigam N. C.
Published: March 2007

The probability structure of the phase derivative of a class of random processes is derived in the time‐ and frequency‐domains. It is shown that in the time‐domain the phase derivative reflects the spectral properties of a stationary random process; whereas in the frequency‐domain the phase derivative reflects the non‐stationary character of a modulated white‐noise random process. The analysis provides a theoretical basis for the qualitative conclusions drawn in some recent investigations regarding the properties of the phase derivatives of earthquake ground accelerations.
Natural frequencies of arch dam reservoir system—by a mapping finite element method
Authors: Nath B.
Published: March 2007

A simple mapping finite element method is used to calculate the coupled natural frequencies and mode shapes of realistic arch dam reservoir systems in which the dam is circular cylindrical with non‐uniform cross‐section. This method, in which both the dam and the reservoir domains are mapped into geometrically simpler shapes using cylindrical‐polar transformations, is found to give accurate results, achieved simply and economically.

Results of analysis show that hydrodynamic interaction has a substantial effect on the coupled natural frequencies and mode shapes; also that the effect of water compressibility in the type of dams considered can be ignored without significant loss of accuracy. A simple method is also presented for predicting the water compressibility effect before undertaking detailed response analysis.
Modal damping for torsionally coupled buildings on elastic foundation
Authors: Balendra Thambirajah , Tat Chan Weng , Lee Seng‐Lip
Published: March 2007

A method to determine the approximate normal modes and the modal damping for torsionally coupled buildings on an elastic foundation is presented. The modal damping is determined by an iterative procedure which matches the approximate normal mode solution with the rigorous solution. The response quantity to be matched is selected in a consistent and logical manner. The normal modes and the damping ratios thus found are then used to determine the seismic response of the interaction system by the response spectrum technique.
Dynamic analysis by direct superposition of Ritz vectors
Authors: Wilson Edward L. , Yuan Ming‐Wu , Dickens John M.
Published: March 2007

The solution of the eigenvalue problem for large structures is often the most costly phase of a dynamic response analysis. In this paper, the need for the exact solution of this large eigenvalue problem is eliminated. A new algorithm, based on error minimization, is presented for the generation of a sequence of Ritz vectors. These orthogonal vectors are used to reduce the size of the system. Only Ritz vectors with a large participation factor are used in the subsequent mode superposition analysis. In all examples studied, the superposition of Ritz vectors yields more accurate results, with fewer vectors, than if the exact eigenvectors are used. The proposed method not only reduces computer time requirements significantly but provides an error estimation for the dynamic analysis. The approach automatically includes the advantages of the proven numerical techniques of static condensation, Guyan reduction and static correction due to higher mode truncation.
Free‐field response from inclined SV‐ and P‐waves and Rayleigh‐waves
Authors: Wolf John P. , Obernhuber Pius
Published: March 2007

To identify the key features of the free‐field response for inplane motion, a vast parametric study is performed, varying the location of the control point, the nature of the wave pattern and the site properties. Harmonic excitation for a site consisting of a layer on bedrock is investigated.

The nature of the wave pattern producing the site response is classified with respect to the apparent velocity of the motion propagating horizontally across the site. When the control point is selected at the outcrop of the bedrock, the amplification of the motion to the free surface of the site depends on the angle of incidence of the incoming wave in the bedrock. The amplification of the vertical motion for incident P‐waves hardly depends (with a tendency of being somewhat larger compared to vertical incidence) on the angle of incidence in the bedrock. The amplification of the horizontal motion for incident SV‐waves is affected strongly by the angle of incidence, being larger or smaller than for vertical incidence. Interpreting the two components of the motion at the free surface as arising from a combination of incident P‐ and SV‐waves leads to amplifications within the site (for the horizontal and vertical directions) which do not depend, from a practical point of view, on the angle of incidence and on the prescribed motion up to the fundamental frequency in the horizontal and vertical directions, respectively. The variation of the motion for the first Rayleigh‐mode with depth in the two directions bears comparison, in general, with that of vertically incident waves up to the corresponding fundamental frequency. The higher Rayleigh‐modes lead to a completely different variation with depth. In contrast to Rayleigh‐waves the attenuation of the motion in the horizontal direction for inclined body waves depends on the damping of only the bedrock. Rayleigh‐waves thus attenuate more strongly than body waves, especially in the higher‐frequency range. Generally, higher Rayleigh‐modes attenuate less than the first.
Rocking of slender rigid bodies allowed to uplift
Authors: Psycharis Ioannis N. , Jennings Paul C.
Published: March 2007

Strong shaking of structures during large earthquakes may result in some cases in partial separation of the base of the structure from the foundation. A simplified problem of this type, the dynamic response of a rocking rigid block allowed to uplift, is examined here. Two foundation models are considered: the Winkler foundation and the much simpler ‘two‐spring’ foundation. It is shown that an equivalence between these two models can be established, so that one can work with the much simpler two‐spring foundation. Simple solutions of the equations of motion are developed and simplified methods of analysis are proposed. In general, uplift leads to a softer vibrating system which behaves non‐linearly, although the response is composed of a sequence of linear responses. As a result the apparent rocking period increases with the amount of lift‐off. The corresponding apparent ratio of critical damping decreases, in general, with the amplitude of the response. Compared to the case without lift‐off, the response of the system may increase or decrease because of the uplift, depending on the excitation and the parameters of the system.
Efficient dynamic channeliser based on nonuniform filter banks
Authors: Li Bing , Ge Lin‐dong , Zheng Jin
Published: March 2007

In the multi‐standard communications systems, the intermediate frequency (IF) signal usually consists of several subband signals with nonequal bandwidths and arbitrary band locations, and in some special cases the number, location and bandwidth of the subband signal are dynamically changeable during receiving. This paper presents an efficient architecture based on nonuniform filter banks to channelise these signals. The nonuniform filter bank can be constructed by directly merging the relevant uniform cosine‐modulated filter bank (CMFB) according to the nonuniform matrix. The whole filter design can be boiled down to design a prototype filter that meets some constraints. The proposed structure can be optimised to reduce the computational complexity using the relationships among different decimation factors of different subband signals. Along with signals dynamically changing, new channelisation can be implemented as long as updating the nonuniform matrix. New structure is provided with low cost in hardware and high flexibility. Simulation results are also presented to illustrate its feasibility. Copyright © 2007 John Wiley & Sons, Ltd.
Cortical network for vibrotactile attention: A fMRI study
Authors: Burton Harold , Sinclair Robert J. , McLaren Donald G.
Published: March 2007

We used fMRI to identify brain areas activated during tactile attention tasks. Participants detected the interval containing target stimulation of higher vibrotactile frequency or longer duration. Attributes were selectively or neutrally cued. A control backwards‐counting task included concurrent, but irrelevant corresponding vibrotactile stimulation. Group analyses of average F‐statistic maps, participant conjunction maps, and estimated time courses utilized data mapped to a standard average surface atlas (PALS B12). Repeated‐measures, random‐effects MANOVA examined blood oxygenation level‐dependent (BOLD) signal modulation differences amongst tasks in defined regions, where significant responses occurred in at least 50% of the group. Greater than 0.1% increase in BOLD responses were found during at least one of the tactile attention tasks in contralateral parietal opercular OP1, BA 4 finger region, frontal eye field, dorsal premotor, anterior and posterior BA 7, and bilaterally in superior temporal sulcal cortex (BA 22), ventral premotor, supplementary motor area, and frontal operculum/insula. The same tasks suppressed activity in ipsilateral OP4. The BA 22 ROI showed larger responses during neutral cuing. The control task suppressed BOLD in ipsilateral OP1 and OP4 and bilaterally in BA 40, but significantly enhanced responses in dorsal parietal–frontal regions compared with tactile attention tasks. No regional differences were found between selectively cued frequency and duration tasks. Tactile attention effects were most prominent in OP1. Posterior parietal responses possibly reflected the visual attention required for backwards‐counting, whereas the frontal regions potentially related to goal‐directed behavior when identifying target stimulation. Hum Brain Mapp 2008. © 2007 Wiley‐Liss, Inc.
Chloride, hydrochemical and isotope methods of groundwater recharge estimation in eastern Mediterranean areas: a case study in Jordan
Authors: Zagana E. , Obeidat M. , Kuells Ch. , Udluft P.
Published: March 2007

Jordan is classified as an arid to semi‐arid country with a population according to 1999 estimates of 4·8 millions inhabitants and a growth rate of 3·4%. Efficient use of Jordan's scarce water is becoming increasingly important as the urban population grows. This study was carried out within the framework of the joint European Research project ‘Groundwater recharge in the eastern Mediterranean’ and describes a combined methodology for groundwater recharge estimation in Jordan, the chloride method, as well as isotopic and hydrochemical approaches. Recharge estimations using the chloride method range from 14 mm year−1 (mean annual precipitation of 500 mm) for a shallow and stony soil to values of 3·7 mm year−1 for a thick desert soil (mean annual precipitation of 100 mm) and values of well below 1 mm year−1 for thick alluvial deposits (mean annual rainfall of 250 mm). Isotopically, most of the groundwater in the Hammad basin, east Jordan, falls below the global meteoric water line and far away from the Mediterranean meteoric water line, suggesting that the waters are ancient and were recharged in a climate different than Mediterranean. Tritium levels in the groundwater of the Hammad basin are less than the detection limit (<1·3 TU). However, three samples in east Hammad, where the aquifer is unconfined, present tritium values between 1 and 4 TU. Copyright © 2007 John Wiley & Sons, Ltd.
Methods of groundwater recharge estimation in eastern Mediterranean—a water balance model application in Greece, Cyprus and Jordan
Authors: Zagana E. , Kuells Ch. , Udluft P. , Constantinou C.
Published: March 2007

Groundwater recharge studies in semi‐arid areas are fundamental because groundwater is often the only water resource of importance. This paper describes the water balance method of groundwater recharge estimation in three different hydro‐climatic environments in eastern Mediterranean, in northwest Greece (Aliakmonas basin/Koromilia basin), in Cyprus (Kouris basin and Larnaka area) and in Jordan (northern part of Jordan). For the Aliakmonas basin, groundwater recharge was calculated for different sub‐catchments. For the Upper Aliakmonas basin (Koromilia basin), a watershed‐distributed model was developed and recharge maps were generated on a daily basis. The mean annual recharge varied between 50 and 75 mm/year (mean annual rainfall 800 mm/year). In Cyprus, the mean groundwater recharge estimates yielded 70 mm/year in the Kouris basin. In the Larnaka area, groundwater recharge ranged from 30 mm/year (lowland) to 200 mm/year (mountains). In Jordan, the results indicated recharge rates ranging from 80 mm/year for very permeable karstified surfaces in the upper part of the Salt basin, where rainfall reaches 500 mm/year to less than 10 mm/year and to only about 1 mm/year in the southernmost part of the basin. For the north part of Jordan, a watershed‐distributed model was developed and recharge maps were generated. This water balance model was used for groundwater recharge estimations in many regions with different climatic conditions and has provided reliable results. It has turned out to be an important tool for the management of the limited natural water resources, which require a detailed understanding of regional hydro(geo)logical processes. Copyright © 2007 John Wiley & Sons, Ltd.
Validation of hydrological models for climate scenario simulation: the case of Saguenay watershed in Quebec
Authors: Dibike Yonas B. , Coulibaly Paulin
Published: March 2007

This paper presents the results of an investigation into the problems associated with using downscaled meteorological data for hydrological simulations of climate scenarios. The influence of both the hydrological models and the meteorological inputs driving these models on climate scenario simulation studies are investigated. A regression‐based statistical tool (SDSM) is used to downscale the daily precipitation and temperature data based on climate predictors derived from the Canadian global climate model (CGCM1), and two types of hydrological model, namely the physically based watershed model WatFlood and the lumped‐conceptual modelling system HBV‐96, are used to simulate the flow regimes in the major rivers of the Saguenay watershed in Quebec. The models are validated with meteorological inputs from both the historical records and the statistically downscaled outputs. Although the two hydrological models demonstrated satisfactory performances in simulating stream flows in most of the rivers when provided with historic precipitation and temperature records, both performed less well and responded differently when provided with downscaled precipitation and temperature data. By demonstrating the problems in accurately simulating river flows based on downscaled data for the current climate, we discuss the difficulties associated with downscaling and hydrological models used in estimating the possible hydrological impact of climate change scenarios. Copyright © 2007 John Wiley & Sons, Ltd.
Subsurface storm flow formation at different hillslopes and implications for the ‘old water paradox’
Authors: Kienzler Peter Matthias , Naef Felix
Published: March 2007

Although many studies over the past several decades have documented the importance of subsurface stormflow (SSF) in hillslopes, its formation is still not well understood. Therefore, we studied SSF formation in the vadose soil zone at four different hillslopes during controlled sprinkling experiments and natural rainfall events. Event and pre‐event water fractions were determined using artificially traced sprinkling water and 222Rn as natural tracer. SSF formation and the fraction of pre‐event water varied substantially at different hillslopes. Both intensity of SSF and fraction of pre‐event water depended on whether SSF in preferential flow paths was fed directly from precipitation or was fed indirectly from saturated parts of the soil. Soil water was rapidly mobilized from saturated patches in the soil matrix and was subsequently released into larger pores, where it mixed with event water. Substantial amounts of pre‐event water, therefore, were contained in fast flow components like subsurface storm flow and also in overland flow. This finding has consequences for commonly used hydrograph separation methods and might explain part of the ‘old water paradox’. Copyright © 2007 John Wiley & Sons, Ltd.
Cancer risk in women prenatally exposed to diethylstilbestrol
Authors: Troisi Rebecca , Hatch Elizabeth E. , Titus‐Ernstoff Linda , Hyer Marianne , Palmer Julie R. , Robboy Stanley J. , Strohsnitter William C. , Kaufman Raymond , Herbst Arthur L. , Hoover Robert N.
Published: March 2007

Prenatal diethylstilbestrol (DES) exposure is associated with excess risks of clear cell adenocarcinoma (CCA), and breast cancer in older women. Whether overall cancer risk is also elevated is unclear. Total and site‐specific cancer risks were evaluated in the DES Combined Cohort Follow‐up Study using age‐ and calendar‐year specific standardized incidence rate ratios (SIR), and age‐adjusted incidence rate ratios (RR) comparing DES exposed and unexposed women. A total of 143 and 49 cancer cases occurred in 97,831 and 34,810 person‐years among the exposed and unexposed, respectively. There was no overall excess risk among exposed women when compared with external rates (SIR 1.01; 95% confidence interval [CI] 0.86–1.2). The overall RR comparing exposed with unexposed women was 1.32 (95% CI 0.94–1.8). Breast cancer risk was elevated only among women over 40 years (RR 1.83; 95% CI 1.1–3.2). The CCA SIR among exposed women was nearly 40, and the estimated attack rate through age 39 was 1.6/1,000 women. CCA incidence decreased by over 80% after age 25 when compared with 20–24 years. Excluding CCA and breast cancer, the overall RR was 1.21 (95% CI 0.74–2.0). DES was not associated with excess risks of either endometrial or ovarian cancer. These data suggest that the DES associated increase in CCA incidence remains elevated through the reproductive years. There was no consistent evidence of risk excesses for cancers other than CCA, and breast cancer in older women. Given that the population is still young, continued follow‐up is necessary to assess the overall carcinogenic impact of prenatal DES exposure. © 2007 Wiley‐Liss, Inc.
PTHrP‐induced MCP‐1 production by human bone marrow endothelial cells and osteoblasts promotes osteoclast differentiation and prostate cancer cell proliferation and invasion in vitro
Authors: Lu Yi , Xiao Guozhi , Galson Deborah L. , Nishio Yoshihiko , Mizokami Atsushi , Keller Evan T. , Yao Zhi , Zhang Jian
Published: March 2007

Prostate cancer (PCa) preferentially metastasizes to bone resulting in osteoblastic lesions with underlying osteolytic activities. The mechanisms through which PCa cells promote osteolytic activities and subsequent osteoblastic bone formation remain poorly understood. Parathyroid hormone‐related protein (PTHrP), produced by bone cells and PCa, binds to receptors on osteoblasts and stimulates bone formation and resorption. We have previously reported that MCP‐1 acts as a paracrine and autocrine factor for PCa progression. However, the role of PTHrP in regulating MCP‐1 expression in bone microenvironment, specifically by human bone marrow endothelial cells (HBME) and osteoblasts (hFOB), as well as by PCa cells, has not been studied. Accordingly, we first determined the effect of PTHrP on MCP‐1 expression by bone cells and PCa cells. PTHrP induced both MCP‐1 protein and mRNA expression by HBME and hFOB cells, but not by PCa LNCaP and PC3 cells. To further determine the mechanisms of PTHrP‐induced MCP‐1 transcription, analysis of the MCP‐1 promoter was performed. MCP‐1 promoter activity was induced by PTHrP. Both C/EBPβ and NF‐κB binding elements are required for PTHrP‐induced MCP‐1 transcription. Finally, when a constitutively‐active PTH receptor construct was transfected into HBME and hFOB cells, MCP‐1 production was increased. The conditioned media collected from these cells induced osteoclast differentiation and PC3 proliferation and invasion in vitro. These inductions were partially inhibited by MCP‐1 neutralizing antibody. We conclude that PTHrP‐induced MCP‐1 production by HBME and hFOB cells promotes osteoclast differentiation in vitro and such induction may play a critical role in PCa development in the bone microenvironment. © 2007 Wiley‐Liss, Inc.
Nanomedicine for drug delivery and imaging: A promising avenue for cancer therapy and diagnosis using targeted functional nanoparticles
Authors: Liu Yiyao , Miyoshi Hirokazu , Nakamura Michihiro
Published: March 2007

The diagnosis and treatment of cancer or tumor at the cellular level will be greatly improved with the development of techniques that enable the delivery of analyte probes and therapeutic agents into cells and cellular compartments. Organic and inorganic nanoparticles that interface with biological systems have recently attracted widespread interest in the fields of biology and medicine. The new term nanomedicine has been used recently. Nanoparticles are considered to have the potential as novel intravascular or cellular probes for both diagnostic (imaging) and therapeutic purposes (drug/gene delivery), which is expected to generate innovations and play a critical role in medicine. Target‐specific drug/gene delivery and early diagnosis in cancer treatment is one of the priority research areas in which nanomedicine will play a vital role. Some recent breakthroughs in this field recently also proved this trend. Nanoparticles for drug delivery and imaging have gradually been developed as new modalities for cancer therapy and diagnosis. In this article, we review the significance and recent advances of gene/drug delivery to cancer cells, and the molecular imaging and diagnosis of cancer by targeted functional nanoparticles. © 2007 Wiley‐Liss, Inc.
Osteopontin deficiency and aging on nanomechanics of mouse bone
Authors: Kavukcuoglu N. Beril , Denhardt David T. , Guzelsu Nejat , Mann Adrian B.
Published: March 2007

Osteoporosis is a bone disease characterized by low bone mass and deterioration of the tissue leading to increased fragility. Osteopontin (OPN), a noncollageneous bone matrix protein, has been shown to play an important role in osteoporosis, bone resorption, and mineralization. However, OPN's role in bone mechanical properties on the submicron scale has not been studied in any detail. In this study, nanoindentation techniques were utilized to investigate how OPN and aging affect bone mechanical properties. Hardness and elastic modulus were calculated and compared between the OPN‐deficient mice (OPN−/−) and their age and sex‐matched wild‐type (OPN+/+) controls. The results show that the mechanical properties of the young OPN−/− bones (age < 12 weeks) are significantly lower than that of the youngest OPN+/+ bones. This finding was confirmed by additional microindentation testing. Biochemical analysis using micro‐Raman spectroscopy indicated more mineral content in young OPN+/+ bones. Older (age > 12 weeks) bones did not show any significant differences in mechanical properties with genotype. In addition, OPN+/+ bones show a decrease in mechanical properties between young and older age groups. By contrast, OPN−/− bones showed no significant change in mechanical properties with aging. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Biomedical nanocomposites of hydroxyapatite/polycaprolactone obtained by surfactant mediation
Authors: Kim Hae‐Won
Published: March 2007

The composite approach to combining bioactive ceramic and degradable polymer is a promising strategy in the development of bone regenerative matrices. Moreover, in the fabrication of composites, the nanoscale organization of each component should improve the level of structural integration as well as the resultant mechanical and biological properties. The aim of this study was to develop a novel nanocomposite system consisting of hydroxyapatite (HA) and poly(ε‐caprolactone) (PCL), wherein the HA nanoparticles were uniformly dispersed within the PCL matrix. The strategy was based on applying an amphiphilic surfactant, oleic acid in this case, between the HA and PCL. Oleic acid, which belongs to the fatty acid family and is generally noncytotoxic at the levels used in this study, is believed to mediate the interaction between the hydrophilic HA and hydrophobic PCL. With the mediation of oleic acid, the HA nanoparticles were distributed uniformly within the PCL matrix on the nanoscale (distributed particle size of less than 1 μm), which is in marked contrast to the conventionally mixed HA‐PCL composite, in which the HA particles were severely agglomerated. The developed nanocomposite had significantly higher mechanical strength than did the conventional composite and the pure PCL. Moreover, the osteoblastic cells showed a better proliferation behavior on the nanocomposite than on the conventional composite. This HA‐PCL nanocomposite mediated by oleic acid is expected to be useful in the bone regeneration field. Moreover, this methodology is applicable to the nanocomposite processing of other biomedical materials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Cell morphology, markers, spreading, and proliferation on orthopaedic biomaterials. An innovative cellular model for the “in vitro” study
Authors: Morelli Cristina , Barbanti‐Brodano Giovanni , Ciannilli Alessandra , Campioni Katia , Boriani Stefano , Tognon Mauro
Published: March 2007

The aims of tissue engineering are the in vitro reconstruction of functionally active tissues, and the in vivo induction of their appropriate development. The great progresses in the fields of biology and biomaterials represent key events, which allowed the recent improvement of tissue engineering. In the orthopaedic perspective, tissue engineering is focused on the development of innovative materials, whose action consists in recruiting bone progenitor cells and in stimulating their proliferation. In this context, it should remind that these materials should not only allow cells adhesion and proliferation, but also ensure that attached cells maintain the cellular properties of the original tissue. In this study, a new cellular model, suitable for the rapid in vitro determination of the above parameters, is presented. The cell model derives from a human osteosarcoma cell line, Saos‐2, which maintained the cytological features of the osteoblast cells. The cell line was genetically modified to express constitutively the enhanced green fluorescent protein. The engineered cell line Saos‐eGFP represents a suitable in vitro mode for studying the biocompatibility, the cell adhesion, spreading, and proliferation on biomaterials developed for clinical applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Mechanisms for the magnolol‐induced cell death of CGTH W‐2 thyroid carcinoma cells
Authors: Huang Shih‐Horng , Chen Ying , Tung Po‐Yuan , Wu Jiahn‐Chun , Chen Kuo‐Hsin , Wu Jiann‐Ming , Wang Seu‐Mei
Published: March 2007

Magnolol, a substance purified from the bark of Magnolia officialis, inhibits cell proliferation and induces apoptosis in a variety of cancer cells. The aim of this study was to study the effects of magnolol on CGTH W‐2 thyroid carcinoma cells. After 24 h treatment with 80 µM magnolol in serum‐containing medium, about 50% of the cells exhibited apoptotic features and 20% necrotic features. Cytochrome‐c staining was diffused in the cytoplasm of the apoptotic cells, but restricted to the mitochondria in control cells. Western blot analyses showed an increase in levels of activated caspases (caspase‐3 and ‐7) and of cleaved poly (ADP‐ribose) polymerase (PARP) by magnolol. Concomitantly, immunostaining for apoptosis inducing factor (AIF) showed a time‐dependent translocation from the mitochondria to the nucleus. Inhibition of either PARP or caspase activity blocked magnolol‐induced apoptosis, supporting the involvement of the caspases and PARP. In addition, magnolol activated phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and inactivated Akt by decreasing levels of phosphorylated PTEN and phosphorylated Akt. These data suggest that magnolol promoted apoptosis probably by alleviating the inhibitory effect of Akt on caspase 9. Furthermore, inhibition of PARP activity, but not of caspase activity, completely prevented magnolol‐induced necrosis, suggesting the notion that it might be caused by depletion of intracellular ATP levels due to PARP activation. These results show that magnolol initiates apoptosis via the cytochrome‐c/caspase 3/PARP/AIF and PTEN/Akt/caspase 9/PARP pathways and necrosis via PARP activation. J. Cell. Biochem. 101: 1011–1022, 2007. © 2007 Wiley‐Liss, Inc.
Enhancement of neovascularization with mobilized blood cells transplantaion: Supply of angioblasts and angiogenic cytokines
Authors: Zhou Bin , Liu Peng Xia , Lan Hai Feng , Fang Zhi Hong , Han Zhi Bo , Ren He , Poon Man‐Chiu , Han Zhong Chao
Published: March 2007

We have recently provided evidence that transplantation of G‐CSF mobilized peripheral blood mononuclear cells (M‐PBMNCs) improves limb ischemia in diabetic patients. This method represents a simple, safe, effective, and novel therapeutic approach for diabetic ischemia. Here we investigated the mechanisms by which mobilized blood cells transplantation improves limb ischemia. Unilateral hindlimb ischemia was surgically induced in streptozotocin‐induced diabetic nude mice, and they were intramuscularly injected 106 M‐PBMNCs, or human umbilical vein endothelial cells (HUVECs), PBS controls. We compared their blood‐flow restoration via laser Doppler perfusion image (LDPI), angiogenesis via histological determination of capillary density. Physiological and histological assessment revealed an acceleration of ischemia recovery and increase in capillary density with less apoptosis in M‐PBMNCs group, compared with those in HUVECs and PBS groups. In vivo noninvasive imaging and immunofluorescence revealed the survival, migration, proliferation, differentiation, and incorporation of M‐PBMNCs into foci of vessel networks. More angioblasts were from blood cells after mobilization, and they also produced a number of antiapoptotic and proagniogenic factors that promoted angiogenesis in vivo. M‐PBMNCs and its conditioned medium augmented the vessel formation in matrigel plugs in vivo. Thus, transplantation of M‐PBMNCs achieved therapeutic neovascularization via supply of abundant angioblasts and angiogenic factors. J. Cell. Biochem. 102: 183–195, 2007. © 2007 Wiley‐Liss, Inc.
Interconversion of intra‐ and extra‐chromosomal sites of gene amplification by modulation of gene expression and DNA methylation
Authors: Shimizu Noriaki , Hanada Naoyuki , Utani Kohichi , Sekiguchi Naoki
Published: March 2007

We previously showed that plasmids containing a mammalian replication initiation region and a matrix attachment region were efficiently amplified to few thousand copies per cell, and that they formed extrachromosomal double minutes (DMs) or chromosomal homogeneously staining regions (HSRs). In these structures, the plasmid sequence was arranged as a tandem repeats, and we suggested a mechanism of plasmid amplification. Since amplification was very efficient, easy, and convenient, it might be adapted to a novel method for protein production. In the current study, we found that gene expression from the tandem plasmid repeat was suppressed. We identified several strategies to overcome this suppression, including: (1) use of higher concentrations of antibiotic during cell selection; (2) treatment of cells with agents that influence DNA methylation (5‐azacytidine) or histone acetylation (butyrate); (3) co‐amplification of an insulator sequence; and (4) co‐amplification of sequences that encode a transcriptional activator. Expression from the plasmid repeat was always higher at DMs compared to HSRs. We found that continuous activation of a plasmid‐encoded inducible promoter prevented the generation of long HSRs, and favored amplification at DMs. Consistent with this finding, there was a synergistic effect of transcriptional activation and inhibition of DNA methylation on the fragmentation of long HSRs and the generation of DMs and short HSRs. Our results indicate that both transcriptional activation and DNA methylation regulate the interconversion between extra‐ and intra‐chromosomal gene amplification. These results have important implications for both protein production technology, and the generation of chromosomal abnormalities found in human cancer cells. J. Cell. Biochem. 102: 515–529, 2007. © 2007 Wiley‐Liss, Inc.
Pressurized liquid extraction of pharmaceuticals from sewage‐sludge
Authors: Nieto Antonio , Borrull Francesc , Pocurull Eva , Marcé Rosa Maria
Published: March 2007

A method for the quantitative determination of ten pharmaceuticals in sewage sludge was developed by using pressurized liquid extraction (PLE) and HPLC–MS with ESI (HPLC‐(ESI)MS). The PLE was optimized with regard to solvents and operational parameters, such as temperature, pressure, extraction time, and purge time. The optimum conditions were: 50 mM phosphoric acid/methanol (1:1 v/v) as the extraction solvent, temperature of 100°C, pressure of 100 bar, extraction time 15 min, 2 cycles, flush volume 150% and purge time 300 s. All recoveries for pharmaceuticals were over 68% except for salicylic acid. The repetitivity and reproducibility between days expressed as RSD was lower than 8% for repetitivity and 10% for reproducibility. The LOD of all compounds was lower than 10 μg/kg of dry weight of sewage sludge. The method was applied to determine the pharmaceuticals in sewage sludge from two domestic sewage treatment plants (STPs). The samples were collected every three months between February 2004 and June 2005. Some pharmaceuticals were determined in the samples and naproxen showed the highest value (242 μg/kg of dry weight).
Selectivity in reversed‐phase separations: General influence of solvent type and mobile phase pH
Authors: Neue Uwe D. , Méndez Alberto
Published: March 2007

The influence of the mobile phase on retention is studied in this paper for a group of over 70 compounds with a broad range of multiple functional groups. We varied the pH of the mobile phase (pH 3, 7, and 10) and the organic modifier (methanol, acetonitrile (ACN), and tetrahydrofuran (THF)), using 15 different stationary phases. In this paper, we describe the overall retention and selectivity changes observed with these variables. We focus on the primary effects of solvent choice and pH. For example, transfer rules for solvent composition resulting in equivalent retention depend on the packing as well as on the type of analyte. Based on the retention patterns, one can calculate selectivity difference values for different variables. The selectivity difference is a measure of the importance of the different variables involved in method development. Selectivity changes specific to the type of analyte are described. The largest selectivity differences are obtained with pH changes.
Macromol. Chem. Phys. 6/2007
Authors: Liang Songmiao , Zhang Lina , Li Yanfang , Xu Jian
Published: March 2007

Cover: The picture illustrates a strategy for the preparation of cellulose hydrated membrane via pre‐gelation processing and the interesting surface and bulk structure of the membrane. Further details can be found in the Full Paper S. Liang, L. Zhang,* Y. Li, and J. Xu* on page 594.
Effect of Blend Preparation on Electrical, Dielectric, and Dynamical‐Mechanical Properties of Conducting Polymer Blend: SBS Triblock Copolymer/Polyaniline
Authors: Soares Bluma G. , Leyva Maria Elena
Published: March 2007

Conducting polymer blends based on styrene–butadiene–styrene (SBS) triblock copolymer and polyaniline doped with dodecylbenzene sulfonic acid (Pani.DBSA) were prepared by different procedures: mechanical mixing (MM) and ‘in situ’ polymerization (ISP) methods. The ISP blends exhibited higher levels of electrical conductivity, as compared to MM blends. The scanning electron micrographs of the ISP blend were characterized by the presence of microtubules, which favored the formation of the conducting pathways inside the SBS matrix. From dynamic mechanical and dielectric analysis, it was possible to suggest a higher interaction degree of the polyaniline with the polystyrene phase of the block copolymer. Blends prepared by ISP method displayed also higher dielectric constant and higher dielectric loss factor than blends prepared by MM method.

magnified image
Diffusion of Model Contaminants in High‐Density Polyethylene
Authors: Voultzatis Ioannis S. , Papaspyrides Constantine D. , Tsenoglou Christos J. , Roussis Constantine
Published: March 2007

Four liquid solvents – 1,1,1‐trichloroethane, toluene, chlorobenzene and octane – are used as model contaminants in sorption experiments in polyethylene in order to study their diffusion behavior between 40 and 70 °C and assess the plausibility of utilizing recycled plastics as safe functional barriers in food packaging applications. A hybrid model that combines molecular and free volume theory elements is used to interpret the collected experimental data. This helps in evaluating microstructural characteristics pertaining to the penetrant‐polymer systems tested, correlating these characteristics with the molecular properties of the solvent, and has an eventual role in predicting sorption and diffusivity in similar untested systems.

magnified image