bluuebunny/crossref_metadata_2025 huggingface dataset:
Seismic damage estimation for low‐ and mid‐rise buildings in japan
Authors: Scawthorn C. , Iemura H. , Yamada Y.
Published: March 2007

While much effort has been spent on analysis of individual structures, building class seismic damage estimators, of value in disaster planning, code‐writing, city planning, national hazards policy formulation, etc., have been little investigated. Based largely on data from Sendai City, Japan in the 12 June, 1978 Miyagiken‐oki earthquake (ML = 7.4), estimators of seismic damage for low‐ and mid‐rise buildings in urban Japan have been determined. For low‐rise buildings, based on damage to over 60,000 buildings, damage ratios for onset of damage and collapse and for cost of damage are found to correlate best with response spectra at 0.75 s. Using published test data and average building properties, a seismic damage model explains the low‐rise building behaviour and permits examination of the effect of structural changes on the estimated damage. For mid‐rise buildings, damage states (0: none, 4: total) are determined as a function of maximum storey displacement, based on published natural period determinations (pre‐ and post‐earthquake) for 189 mid‐rise buildings in Sendai. The effects of structural changes on expected damage can also be estimated. With these two building class damage estimators, a large part of future seismic damage to urban Japan can be estimated, as well as the effects of various mitigation measures.
A review of the response of buried pipelines under seismic excitations
Authors: Ariman Teoman , Muleski Gregory E
Published: March 2007

Modern cities depend heavily on utility systems for their day‐to‐day operation and earthquake threats to utility systems become increasingly important in proportion with the level of urbanization. Due to the great potential for destruction, damage and disruption, the seismic problems of utility systems have recently attracted researchers. It became apparent that the seismic behaviour of buried pipeline systems is quite different than that of above‐ground structures. In this paper, an updated and detailed review of the earthquake response and seismic‐resistant design of underground piping systems is presented.
Separation and sliding between soil and structure during strong ground motion
Authors: Toki Kenzo , Sato Tadanobu , Miura Fusanori
Published: March 2007

This paper presents an approach to the problem of separation and sliding between soil and structure in the finite element analysis of dynamic soil‐structure interaction problems. Joint elements are arranged along the contact surface between soil and structure and they have a property such that tensile forces are not transmitted between the planes representing structure and soil in the finite element analysis. The dynamic properties governing the sliding are determined by the Mohr‐Coulomb failure law determined from the cohesion and the friction angle between soil and structure.

The proposed method is applied to (i) a model of a reactor building resting on the free surface of layered ground and (ii) a buried foundation structure. The numerical computations reveal the following results: that the translation is dominant in the motion of the structure when sliding is taking place between soil and structure, and that the rocking is dominant in the rest of the response. The amplitude of the response during sliding is increased on any one point of the structure and decreased on any one point of the ground compared with that of the fixed condition at the interface. In the case of the buried structure, it is observed in the computed results that the structure and soil move in the opposite direction along the vertical contact surface and are separated from each other in the near surface region during the strong phase of the excitation.
Earthquake analysis of concrete gravity dams including dam‐water‐foundation rock interaction
Authors: Chopra Anil K. , Chakrabarti P.
Published: March 2007

A general procedure for analysis of the response of concrete gravity dams, including the dynamic effects of impounded water and flexible foundation rock, to the transverse (horizontal) and vertical components of earthquake ground motion is presented. The problem is reduced to one in two dimensions, considering the transverse vibration of a monolith of the dam. The system is analysed under the assumption of linear behaviour for the concrete, foundation rock and water.

The complete system is considered as composed of three substructures—the dam, represented as a finite element system, the fluid domain, as a continuum of infinite length in the upstream direction, and the foundation rock region as a viscoelastic half‐plane. The structural displacements of the dam are expressed as a linear combination of Ritz vectors, chosen as normal modes of an associated undamped dam‐rock system. The effectiveness of this analytical formulation lies in its being able to produce excellent results by considering only a few Ritz vectors. The generalized displacements due to earthquake motion are computed by synthesizing their complex frequency responses using Fast Fourier Transform procedures. The stress responses are calculated from the displacements.

An example analysis is presented to illustrate results obtained from this analytical procedure. Computation times for several analyses are presented to illustrate the effectiveness of the procedure.
Transient response of a thick beam of bimodular material
Authors: Bert C. W. , Tran A. D.
Published: March 2007

Certain materials have different elastic behaviour when they are loaded in tension as compared to compression. As an engineering approximation, they are usually modelled as a bimodular material, i.e. a bilinear material having different Young's moduli in tension and in compression. All of the previous analyses of bimodular beams known to the present investigators have been concerned with either static loading or harmonic vibration. Thus, the present work is believed to be the first to consider transient response of such beams. The transfer‐matrix method is used to discretize spatially, while the timewise discretization is accomplished by use of the Newmark beta method.
Engineering analyses of smart 1 array accelerograms
Authors: Loh C. H. , Penzien J. , Tsai Y. B.
Published: March 2007

Presented are the results of engineering analyses of selected accelerograms recorded by the SMART 1 strong motion array in Taiwan which is described in a companion paper by B. A. Bolt, Y. B. Tsai, K. Yeh and M. K. Hsu, entitled Earthquake Strong Motions Recorded by a Large Near‐source Array of Digital Seismographs. These analyses include (1) transformations to principal axes, (2) generation of Fourier amplitude spectra, (3) development of generalized response spectrum ratios for characterizing multi‐support excitations and (4) moving window analyses in the time and frequency domains for studying the spatial variations of recorded ground motions.
A friction damped base isolation system with fail‐safe characteristics
Authors: Kelly James M. , Beucke Karl E.
Published: March 2007

An experimental study of a Coulomb friction damped aseismic base isolation system with fail‐safe characteristics is described in this paper. The base isolation system utilized commercially made natural rubber bearings and a skid system which comes into operation at preset‐levels of relative horizontal displacement between the structure and the foundation. The fail‐safe skid provides hysteretic damping and prevents failure of the isolation system in the event of displacements larger than those assumed in the original design. The isolation system can be designed for an earthquake which can be reasonably expected within the lifetime of the structure; in the event of an earthquake of unanticipated intensity the failsafe system will prevent collapse of the structure.

The testing of the system involved an 80,000lb model, approximately 1/3 scale to a real structure mounted on the 20′ × 20′ shaking table at EERC and subject to a variety of earthquake inputs. The results show that the hysteretic effect of the fail‐safe system does not greatly increase the accelerations experienced by the structure but considerably reduces the relative displacements at the isolation bearings. The action of the fail‐safe system was tested by using an earthquake input that produced a resonant response in the isolated mode of the model. The stability limit of the isolation system was exceeded and the bearings failed but complete failure of the isolation system and thus collapse of the model was prevented by the fail‐safe system. The implementation of the system in full scale structures poses no technical or construction problems.

An equivalent linearization technique was developed for this system for design purposes using response spectra. The accuracy of this approach was verified by comparison with the experimental results.
Functional source separation applied to induced visual gamma activity
Authors: Barbati Giulia , Porcaro Camillo , Hadjipapas Avgis , Adjamian Peyman , Pizzella Vittorio , Romani Gian Luca , Seri Stefano , Tecchio Franca , Barnes Gareth R.
Published: March 2007

Objective of this work was to explore the performance of a recently introduced source extraction method, FSS (Functional Source Separation), in recovering induced oscillatory change responses from extra‐cephalic magnetoencephalographic (MEG) signals. Unlike algorithms used to solve the inverse problem, FSS does not make any assumption about the underlying biophysical source model; instead, it makes use of task‐related features (functional constraints) to estimate source/s of interest. FSS was compared with blind source separation (BSS) approaches such as Principal and Independent Component Analysis, PCA and ICA, which are not subject to any explicit forward solution or functional constraint, but require source uncorrelatedness (PCA), or independence (ICA). A visual MEG experiment with signals recorded from six subjects viewing a set of static horizontal black/white square‐wave grating patterns at different spatial frequencies was analyzed. The beamforming technique Synthetic Aperture Magnetometry (SAM) was applied to localize task‐related sources; obtained spatial filters were used to automatically select BSS and FSS components in the spatial area of interest. Source spectral properties were investigated by using Morlet‐wavelet time‐frequency representations and significant task‐induced changes were evaluated by means of a resampling technique; the resulting spectral behaviours in the gamma frequency band of interest (20–70 Hz), as well as the spatial frequency‐dependent gamma reactivity, were quantified and compared among methods. Among the tested approaches, only FSS was able to estimate the expected sustained gamma activity enhancement in primary visual cortex, throughout the whole duration of the stimulus presentation for all subjects, and to obtain sources comparable to invasively recorded data. Hum Brain Mapp 29:131–141, 2008. © 2007 Wiley‐Liss, Inc.
Dp71ab/DAPs complex composition changes during the differentiation process in PC12 cells
Authors: Romo‐Yáñez J. , Ceja V. , Ilarraza‐Lomelí R. , Coral‐Vázquez R. , Velázquez F. , Mornet D. , Rendón A. , Montañez C.
Published: March 2007

PC12 cells express different Dp71 isoforms originated from alternative splicing; one of them, Dp71ab lacks exons 71 and 78. To gain insight into the function of Dp71 isoforms we identified dystrophin associated proteins (DAPs) that associate in vivo with Dp71ab during nerve growth factor (NGF) induced differentiation of PC12 cells. DAPs expression was analyzed by RT–PCR, Western blot and indirect immunofluorescence, showing the presence of each mRNA and protein corresponding to α‐, β‐, γ‐, δ‐, and ε‐sarcoglycans as well as ζ‐sarcoglycan mRNA. Western blot analysis also revealed the expression of β‐dystroglycan, α1‐syntrophin, α1‐, and β‐dystrobrevins. We have established that Dp71ab forms a complex with β‐dystroglycan, α1‐syntrophin, β‐dystrobrevin, and α‐, β‐ and γ‐sarcoglycans in undifferentiated PC12 cells. In differentiated PC12 cells, the complex composition changes since Dp71ab associates only with β‐dystroglycan, α1‐syntrophin, β‐dystrobrevin, and δ‐sarcoglycan. Interestingly, neuronal nitric oxide synthase associates with the Dp71ab/DAPs complex during NGF treatment, raising the possibility that Dp71ab may be involved in signal transduction events during neuronal differentiation. J. Cell. Biochem. 102: 82–97, 2007. © 2007 Wiley‐Liss, Inc.
PPARβ agonists trigger neuronal differentiation in the human neuroblastoma cell line SH‐SY5Y
Authors: Di Loreto S. , D'Angelo B. , D'Amico M.A. , Benedetti E. , Cristiano L. , Cinque B. , Cifone M.G. , Cerù M.P. , Festuccia C. , Cimini A.
Published: March 2007

Neuroblastomas are pediatric tumors originating from immature neuroblasts in the developing peripheral nervous system. Differentiation therapies could help lowering the high mortality due to rapid tumor progression to advanced stages. Oleic acid has been demonstrated to promote neuronal differentiation in neuronal cultures. Herein we report on the effects of oleic acid and of a specific synthetic PPARβ agonist on cell growth, expression of differentiation markers and on parameters responsible for the malignancy such as adhesion, migration, invasiveness, BDNF, and TrkB expression of SH‐SY5Y neuroblastoma cells. The results obtained demonstrate that many, but not all, oleic acid effects are mediated by PPARβ and support a role for PPARβ in neuronal differentiation strongly pointing towards PPAR ligands as new therapeutic strategies against progression and recurrences of neuroblastoma. J. Cell. Physiol. 211: 837–847, 2007. © 2007 Wiley‐Liss, Inc.
Inductively coupled plasma mass spectrometry (ICP MS): a versatile tool
Authors: Ammann Adrian A.
Published: March 2007

Inductively coupled plasma (ICP) mass spectrometry (MS) is routinely used in many diverse research fields such as earth, environmental, life and forensic sciences and in food, material, chemical, semiconductor and nuclear industries. The high ion density and the high temperature in a plasma provide an ideal atomizer and element ionizer for all types of samples and matrices introduced by a variety of specialized devices. Outstanding properties such as high sensitivity (ppt–ppq), relative salt tolerance, compound‐independent element response and highest quantitation accuracy lead to the unchallenged performance of ICP MS in efficiently detecting, identifying and reliably quantifying trace elements. The increasing availability of relevant reference compounds and high separation selectivity extend the molecular identification capability of ICP MS hyphenated to species‐specific separation techniques. While molecular ion source MS is specialized in determining the structure of unknown molecules, ICP MS is an efficient and highly sensitive tool for target‐element orientated discoveries of relevant and unknown compounds. This special‐feature, tutorial article presents the principle and advantages of ICP MS, highlighting these using examples from recently published investigations. Copyright © 2007 John Wiley & Sons, Ltd.
Comparison of interpolation methods for mapping climatic and bioclimatic variables at regional scale
Authors: Attorre Fabio , Alfo' Marco , De Sanctis Michele , Francesconi Fabio , Bruno Franco
Published: March 2007

Climatic data and bioclimatic indexes have been used to study plants, animals and ecosystem distribution. GIS‐based maps of climatic and bioclimatic data can be obtained by interpolating values observed at measurement stations. Since no single method can be considered as optimal for all observed regions, a major task is to propose comparisons between results obtained using different methods applied to the same data set of climate variables. We compared three methods that have been proved to be useful at regional scale: 1 ‐ a local interpolation method based on de‐trended inverse distance weighting (D‐IDW), 2 ‐ universal kriging (i.e. simple kriging with trend function defined on the basis of a set of covariates) which is optimal (i.e. BLUP, best linear unbiased predictor) if spatial association is present, 3 ‐ multilayer neural networks trained with backpropagation (representing a complex nonlinear fitting). Long‐term (1955–1990) average monthly data were obtained from weather stations measuring precipitation (201 sites) and temperature (102 sites). We analysed twelve climatic variables (temperature and precipitation) and nine bioclimatic indexes. Terrain variables and geographical location have been used as predictors of the climate variables: longitude, latitude, elevation, aspect, slope, continentality and estimated solar radiation. Based on the root mean square errors from cross‐validation tests, we ranked the best method for each variable data set. Universal kriging with external drift obtained the best performances for seventeen variables of the twenty‐one analysed, neural network interpolator has proven to be more efficient for three variables and D‐IDW for only one. Based on these results, we used the universal kriging estimates to produce the climatic and bioclimatic maps aimed at defining the bioclimatic envelope of species. Copyright © 2007 Royal Meteorological Society
A comparative study of composition and postharvest performance of organically and conventionally grown kiwifruits
Authors: Amodio Maria L , Colelli Giancarlo , Hasey Janine K , Kader Adel A
Published: March 2007

Postharvest performance of organic and conventional ‘Hayward’ kiwifruits grown on the same farm in Marysville, California, and harvested at the same maturity stage were compared in this study. Quality parameters monitored included morphological (shape index) and physical (peel characteristics) attributes of the initial samples. Maturity indices (CO2 and C2H4 production, firmness, color, soluble solids content and acidity) and content of compounds associated with flavor and nutritional quality (minerals, sugars and organic acids, ascorbic acid, total phenolics, and antioxidant activity) were determined at 0, 35, 72, 90 and 120 days of storage at 0°C, and after 1 week of shelf‐life simulation at 20°C, after each storage duration. Organically and conventionally grown kiwifruits had similar soluble solids content at harvest, but conventional kiwifruits had a higher firmness and L* value, and a lower hue angle and chromaticity, resulting in a lighter green color when compared with the organic kiwifruits. These differences were maintained for all the storage durations, with the soluble solids content increasing more in conventionally grown kiwifruits. The two production systems resulted in different morphological attributes since organic kiwifruits exhibited a larger total and columella area, smaller flesh area, more spherical shape, and thicker skin compared to conventional kiwifruits. All the main mineral constituents were more concentrated in organic kiwifruits, which also had higher levels of ascorbic acid and total phenol content, resulting in a higher antioxidant activity. Sugars and organic acids composition was not affected by the production system. Copyright © 2007 Society of Chemical Industry
Hydrophilic surface modification of cyclic olefin copolymer microfluidic chips using sequential photografting
Authors: Stachowiak Timothy B. , Mair Dieudonne A. , Holden Tyler G. , Lee L. James , Svec Frantisek , Fréchet Jean M. J.
Published: March 2007

The plastic material known as cyclic olefin copolymer (COC) is a useful substrate material for fabricating microfluidic devices due to its low cost, ease of fabrication, excellent optical properties, and resistance to many solvents. However, the hydrophobicity of native COC limits its use in bioanalytical applications. To increase surface hydrophilicity and reduce protein adsorption, COC surfaces were photografted with poly(ethylene glycol) methacrylate (PEGMA) using a two‐step sequential approach: covalently‐bound surface initiators were formed in the first step and graft polymerization of PEGMA was then carried out from these sites in the second step. Contact angle measurements were used to monitor and quantify the changes in surface hydrophilicity as a function of grafting conditions. As water droplet contact angles decreased from 88° for native COC to 45° for PEGMA‐grafted surfaces, protein adsorption was also reduced by 78% for the PEGMA‐modified COC microchannels as determined by a fluorescence assay. This photografting technique should enable the use of COC microdevices in a variety of bioanalytical applications that require minimal nonspecific adsorption of biomolecules.
The analysis of laser light scattering during rheumatoid arthritis by image segmentation
Authors: Minet O , Gajewski H , Griepentrog J A , Beuthan J
Published: March 2007

Optical imaging in biomedicine is governed by the light absorption and scattering interaction on microscopic and macroscopic constituents in the medium. Therefore, light scattering characteristics of human tissue correlates with the stage of some diseases. In the near infrared range the scattering event with the coefficient approximately two orders of magnitude greater than absorption plays a dominant role. The potential of an experimental laser diode based setup for the transillumination of rheumatoid finger joints and the pattern of the stray light detection are demonstrated. For evaluating the scattering light images a new non-local image segmentation method is presented. Regarding a noisy picture as a multicomponent mixture of gray scaled particles, this method minimizes a non-convex free energy functional under the constraint of mass conservation of the components. Contrary to constructing equilibrium distributions as steady states of an adequate evolution equation, a direct descent method for the free energy is used to separate the components of the image.
Miscibility and Phase Morphology of MF/PVAc Hybrid Resins for Surface Bonding of Building Interior Materials
Authors: Kim Sumin , Kim Hyun‐Joong
Published: March 2007

The objective of this research was to investigate the miscibility behavior of melamine‐formaldehyde resin and poly(vinyl acetate) blends for use as adhesives for surface materials in order to reduce formaldehyde emission. The investigation was conducted using differential scanning calorimetry, Fourier transform infrared spectroscopy, 13C CP/MAS solid state NMR, scanning electron microscope, atomic force microscopy and wide‐angle X‐ray scattering. Blends of various MF resin/PVAc weight compositions, comprising 0, 30, 50, 70 and 100%, were prepared in order to determine and compare the effect of PVAc content. These blends displayed a single cure temperature over the entire range of compositions indicating that this blend system was miscible in the amorphous phase due to the formation of hydrogen bonding between the amine groups of the MF resin and the carbonyl groups of PVAc. On the surface of the cured blends, the homogeneous dispersion of the PVAc phase in the MF resin was evident as small spherical domains and the blends were confirmed to be well combined.

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Dynamics of Stress Bearing Particle Networks in Poly(propylene)/Alumina Nanohybrids
Authors: Acierno Domenico , Filippone Giovanni , Romeo Giovanni , Russo Pietro
Published: March 2007

In this work, we report about the relationships between the linear rheology and the microstructure of a polymer‐nanoparticle model system (i‐PP/Al2O3 nanospheres). Over a critical particle volume fraction, rheological evolutions during a quasi‐quiescent thermal annealing indicate the formation of a whole‐space‐spanning transient network of Al2O3 nanospheres, as confirmed by transmission electron microscopy. The dynamics of this network, responsible for the liquid‐like to solid‐like transition of the nanohybrid, have been investigated by means of rheological measurements. Once the network had formed, the application of large amplitude oscillatory shear progressively and irreversibly destroyed it, leading to a flow‐induced structure unable to contribute to the elasticity of the nanohybrid. Conversely, if the large deformation is applied to an unstructured sample, a solid‐like feature still emerges by ageing the sample. The resulting strength of such a nanohybrid, however, was lower than that obtainable without the application of large deformations. Energetic considerations may explain the transient nanoparticle network dynamics, strictly related to the bulk rheological properties.

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On the Natural Draw Ratio of Semi‐Crystalline Polymers: Review of the Mechanical, Physical and Molecular Aspects
Authors: Séguéla Roland
Published: March 2007

Drawing of semi‐crystalline polymers generally involves a necking phenomenon, which is often referred to as plastic instability. The draw ratio in the stable neck is called natural draw ratio. A review is made of papers dealing with the phenomenology of necking and endeavors to identify its physical origin. The destruction of the spherulitic structure that consists of chain‐folded lamellae involves a strain‐softening accompanied with a localization of the plastic deformation. In turn, the fibrillar transition that results from the lamellar fragmentation and subsequent rearrangement of the crystal blocks into microfibrils brings about a strain‐hardening, which stabilizes the plastic deformation. These competitive processes give rise to the natural draw ratio. The macromolecular network that consists of both chain entanglements and intercrystalline tie molecules appears to be a major factor of the neck stabilization. Theoretical approaches of the phenomenon are critically reviewed. Finally, the practical usefulness of the natural draw ratio is discussed with regard to predicting the long‐term mechanical behavior of high‐density polyethylene.

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Recent Developments of New Components for Dental Adhesives and Composites
Authors: Moszner Norbert , Salz Ulrich
Published: March 2007

The currently used commercial self‐etching enamel‐dentin adhesives and restoratives composites are mainly based on a mixture of various monofunctional and cross‐linking dimethacrylates. New developments of enamel‐dentin adhesives concern the improvement of technique insensitivity and storage stability. Improvements of restorative composites are focused on the reduction of the polymerisation shrinkage, as well as the improvement of wear resistance, biocompatibility, and processing properties. In the past five years, many research efforts have been carried out to develop new monomers and tailor‐made components for filling materials, such as fillers or initiators. New phosphonic acid ether acrylates and cross‐linking bis(acrylamide)s enable the preparation of self‐etching enamel‐dentin adhesives with improved storage stability. With free‐radically polymerisable cyclic monomers, such as bicyclic cyclopropyl acrylates or cyclic allyl sulfides, low‐shrinkage storage‐stable restorative composites could be prepared. In case of the cationic polymerisable cyclic monomers, like siloxane‐based cycloaliphatic epoxides, the lower curing rate, stronger exothermic effect and lower curing depth compared to dimethacrylate‐based composites presently prevent their dental application. Designed methacrylates with tailor‐made properties and sol‐gel polycondensates can also contribute to the improvement of the currently used restorative composites. Radical polymerisable dental materials are initiated by light curing and by redox initiator systems. Under acidic conditions amine containing initiator systems are deactivated by acid‐base reaction. Non amine‐based initiators have to be developed for acidic monomer containing dental materials. The use of discrete nano‐filler particles mainly concerns the reinforcement and, in some cases, the increase of X‐ray opacity of composite filling materials.

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Novel dual‐band filter using slotline and microstrip resonators
Authors: Zhang Xiu Yin , Chen Jian‐Xin , Xue Quan
Published: March 2007

A novel dual‐band filter using slotline and microstrip resonators is proposed. By introducing slotline resonators on the ground of conventional microstrip resonator, the filter provides two transmission paths for RF signals. Each path generates its own passband. Both microstrip resonator and slotline resonators share the input and output ports without any external impedance‐matching network. Deep rejection between the two passbands is obtained due to a transmission zero located between them. The filter has the advantages of low insertion loss, compact size, and good selectivity. The simulated and measured results are presented and show good agreements. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1080–1081, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22348
Theoretical and experimental performance evaluation of all‐optical multiwavelength conversion by four‐wave mixing in fiber at 10/20/40 Gb/s for optical layer multicast
Authors: Yan N. , Teixeira A. , Silveira T. , Beleffi G. M. T. , Curti F. , Forin D. , Longa F. D. , Monroy I. T. , Monteiro P. , Koonen T.
Published: March 2007

All‐optical multiwavelength conversion (MWC) enables optical layer multicast without electronic processing. Wavelength conversion by four‐wave‐mixing (FWM) offers strict transparency in bit rate and modulation format. In this letter, a novel FWM MWC scheme is proposed, supported by theoretical analysis and experimental performance evaluation at 10/20/40 Gb/s. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49:1067–1071, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22358
A new wideband planar antenna with hyperpolar‐transformed Sierpinski carpet
Authors: Lee Gabsoo , Kim Youngsik
Published: March 2007

This paper presents a novel design of the printed hyperpolar‐transformed Sierpinski carpet (HSC) antenna. The design parameter and performance of the proposed monopole antenna are investigated and show that HSC geometry gives more freedom for wideband antenna design such as flare angle, scale factor, iteration number, etc. The simulated and measured results are well agreed and we can get octave bandwidth matching performance. The measured results of the return loss, radiation pattern, and antenna gain are also given. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1090–1092, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22361
Compact dual‐band slot‐antenna for WLAN applications
Authors: Tao J. , Cheng C. H. , Zhu H. B.
Published: March 2007

A novel dual‐band slot‐antenna for WLAN applications is presented. The antenna is composed of two narrow slots fed by a microstrip‐line. In order to increase the impedance bandwidth of a narrow slot and keep its small size, a kind of stepped‐impedance (SI) slot is used. It has been investigated experimentally for its impedance bandwidth, radiation pattern, and gain over its operation frequency band. Result shows that the antenna has a 10% bandwidth from 2.25 to 2.53 GHz and a 15% bandwidth from 5.13 to 5.99 GHz. And a good radiation pattern and gain can be achieved over the frequency range. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1203–1204, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22395
Direct noninvasive quantification of lactate and high energy phosphates simultaneously in exercising human skeletal muscle by localized magnetic resonance spectroscopy
Authors: Meyerspeer Martin , Kemp Graham J. , Mlynárik Vladimir , Krššák Martin , Szendroedi Julia , Nowotny Peter , Roden Michael , Moser Ewald
Published: March 2007

A novel method based on interleaved localized 31P‐ and 1H MRS is presented, by which lactate accumulation and the accompanying changes in high energy phosphates in human skeletal muscle can be monitored simultaneously during exercise and recovery. Lactate is quantified using a localized double quantum filter suppressing the abundant lipid signals while taking into account orientation dependent signal modulations. Lactate concentration after ischemic exercise directly quantified by DQF 1H spectroscopy was 24 ± 3 mmol/L cell water, while 22 ± 3 mmol/L was expected on the basis of 31P MRS acquired simultaneously. Lactate concentration in a sample of porcine meat was estimated to be 40 ± 7 mmol/L by means of DQF quantitation, versus 39 ± 5 mmol/L by biochemical methods. Excellent agreement is shown between lactate concentrations measured noninvasively by 1H MRS, measured biochemically ex vivo, and inferred indirectly in vivo from changes in pH, Pi, and PCr as obtained from 31P MRS data. Magn Reson Med 57:654–660, 2007. © 2007 Wiley‐Liss, Inc.
Hip dGEMRIC in asymptomatic volunteers and patients with early osteoarthritis: The influence of timing after contrast injection
Authors: Tiderius Carl J. , Jessel Rebecca , Kim Young‐Jo , Burstein Deborah
Published: March 2007

Eight asymptomatic volunteers and 10 patients with early hip osteoarthritis (OA) were investigated with hip delayed gadolinium‐enhanced MRI of cartilage (dGEMRIC) at 30, 65, 100, and 135 min after IV injection with Gd‐DTPA2–. In asymptomatic volunteers there was a decrease in the dGEMRIC index (T1(Gd)) between 30 and 100 min. In patients the wash‐in of Gd‐DTPA2– was faster, with a low T1(Gd) at 30 min that did not change significantly over time. Therefore, earlier time points showed a larger separation in T1(Gd) between asymptomatic and OA hips, with more convenient timing logistics. However, T1(Gd) at 30 min had a larger standard deviation (SD) in the OA group, possibly due to variability of the steep slope of wash‐in. This sensitivity to the imaging window may be less desirable for longitudinal studies in which reproducibility is a concern. At all time points, T1(Gd) was 20–30% lower in patients than in asymptomatic volunteers (P < 0.003), which demonstrates the sensitivity of dGEMRIC to early hip OA. Magn Reson Med 57:803–805, 2007. © 2007 Wiley‐Liss, Inc.
Puzzle‐based storage systems
Authors: Gue Kevin R. , Kim Byung Soo
Published: March 2007

We introduce and develop models for a physical goods storage system based on the 15‐puzzle, a classic children's game in which 15 numbered tiles slide within a 4 × 4 grid. The objective of the game is to arrange the tiles in numerical sequence, starting from a random arrangement. For our purposes, the tiles represent totes, pallets, or even containers that must be stored very densely, and the objective is to maneuver items to an input–output point for retrieval or processing. We develop analytical results for storage configurations having a single empty location (as in the game) and experimental results for configurations with multiple empty locations. Designs with many empty locations can be made to form aisles, allowing us to compare puzzle‐based designs with traditional aisle‐based designs found in warehousing systems. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Polyurethane‐nanocomposite materials via in situ polymerization into organoclay interlayers
Authors: Rehab Ahmed , Akelah Ahmed , Agag Tarek , Shalaby Nasser
Published: March 2007

New nanocomposite materials based on polyurethane intercalated into organoclay layers have been synthesized via in situ polymerization. The syntheses of polyurethane–organoclay hybrid films were carried out by swelling the organoclay [12‐aminododecanoic acid montmorillonite] into different kinds of diols followed by addition of diisocyanate then casting in a film. The homogeneous dispersion of MMT in the polymer matrix is evidenced by scanning electron microscope and x‐ray diffraction, which showed the disappearance of the peak characteristic to d001 spacing. It was found that the presence of organoclay has improved the thermal, solvent resistance and mechanical properties. Also, the tensile strength is increased with increasing the organoclay contents to 20% by the ratio 182% related to the PU with 0% organoclay. On the contrary, the elongation has decreased with increasing the organoclay contents. Copyright © 2007 John Wiley & Sons, Ltd.
Laser ablation of SiO2for locally contacted Si solar cells with ultra‐short pulses
Authors: Engelhart Peter , Hermann Sonja , Neubert Tobias , Plagwitz Heiko , Grischke Rainer , Meyer Rüdiger , Klug Ulrich , Schoonderbeek Aart , Stute Uwe , Brendel Rolf
Published: March 2007

We apply ultra‐short pulse laser ablation to create local contact openings in thermally grown passivating SiO2layers. This technique can be used for locally contacting oxide passivated Si solar cells. We use an industrially feasible laser with a pulse duration of τpulse ∼ 10 ps. The specific contact resistance that we reach with evaporated aluminium on a 100 Ω/sq and P‐diffused emitter is in the range of 0·3–1 mΩ cm2. Ultra‐short pulse laser ablation is sufficiently damage free to abandon wet chemical etching after ablation. We measure an emitter saturation current density ofJ0e = (6·2 ± 1·6) × 10−13 A/cm2on the laser‐treated areas after a selective emitter diffusion withRsheet ∼ 20 Ω/sq into the ablated area; a value that is as low as that of reference samples that have the SiO2layer removed by HF‐etching. Thus, laser ablation of dielectrics with pulse durations of about 10 ps is well suited to fabricate high‐efficiency Si solar cells. Copyright © 2007 John Wiley & Sons, Ltd.
Surface heating by transvaginal transducers
Authors: Calvert J. , Duck F. , Clift S. , Azaime H.
Published: March 2007

Objective

This safety study was designed to investigate tissue heating close to the surface of transvaginal ultrasound transducers, with the objective of assessing the validity of manufacturing safety standards set by the International Electrotechnical Commission (IEC).

Methods

The transducers investigated in this study were held in contact with a layered soft‐tissue mimicking material (TMM), and the temperature increase was measured at various depths using a miniature thermocouple. The temperature rise at 200 s was recorded, and the measured profiles of temperature rise with depth were compared with profiles predicted from both analytical and numeric models. Two transvaginal transducers of different manufacturers were investigated, operating in B‐mode imaging, color‐flow imaging and pulsed Doppler modes, using scanner settings giving acoustic output power towards the upper end of that available.

Results

The greatest heating always occurred at the interface between the transducer and the TMM, and it reduced to about 0.1 times the surface temperature rise at a depth of 1 cm. A local maximum was observed in pulsed Doppler mode. A three‐dimensional finite‐element model which accounted for transducer dimensions gave a better prediction of temperature increase than a simple analytical model. The temperature profiles were compared with the depth of fetal tissue measured from a small survey of clinical scans.

Conclusions

It is provisionally concluded that the transducer surface temperature rise of 6 °C allowed to manufacturers by the IEC may give rise to an associated worst‐case contribution to temperature rise due to the transducer, in fetal tissue, of between 0.5 and 1 °C at 1‐cm depth. The contribution to tissue heating at 2 cm and deeper is negligible. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Application of Local Linear Embedding to Nonlinear Exploratory Latent Structure Analysis
Authors: Wang Haonan , Iyer Hari
Published: March 2007

In this paper we discuss the use of a recent dimension reduction technique called Locally Linear Embedding, introduced by Roweis and Saul, for performing an exploratory latent structure analysis. The coordinate variables from the locally linear embedding describing the manifold on which the data reside serve as the latent variable scores. We propose the use of semiparametric penalized spline methods for reconstruction of the manifold equations that approximate the data space. We also discuss a crossvalidation strategy that can guide in selecting an appropriate number of latent variables. Synthetic as well as real data sets are used to illustrate the proposed approach. A nonlinear latent structure representation of a data set also serves as a data visualization tool.
A Class of Multidimensional IRT Models for Testing Unidimensionality and Clustering Items
Authors: Bartolucci Francesco
Published: March 2007

We illustrate a class of multidimensional item response theory models in which the items are allowed to have different discriminating power and the latent traits are represented through a vector having a discrete distribution. We also show how the hypothesis of unidimensionality may be tested against a specific bidimensional alternative by using a likelihood ratio statistic between two nested models in this class. For this aim, we also derive an asymptotically equivalent Wald test statistic which is faster to compute. Moreover, we propose a hierarchical clustering algorithm which can be used, when the dimensionality of the latent structure is completely unknown, for dividing items into groups referred to different latent traits. The approach is illustrated through a simulation study and an application to a dataset collected within the National Assessment of Educational Progress, 1996.
Direct comparison of transcardiac difference between brain natriuretic peptide (BNP) and N‐terminal pro‐BNP in patients with chronic heart failure
Authors: Tsutamoto Takayoshi , Sakai Hiroshi , Ishikawa Chitose , Fujii Masanori , Tanaka Toshinari , Yamamoto Takashi , Takashima Hiroyuki , Ohnishi Masato , Wada Atsuyuki , Horie Minoru
Published: March 2007

Background:

Direct comparison of transcardiac increase in brain natriuretic peptide (BNP) and NT‐pro‐BNP has not been performed previously.

Aims:

To evaluate the relation between BNP and NT‐pro‐BNP secretion, plasma levels and renal function.

Methods:

We measured the plasma levels of BNP and NT‐pro‐BNP in the aortic root and coronary sinus in 326 consecutive patients with chronic heart failure (CHF). Patients were divided into two groups [group I: estimated glomerular filtration rate (eGFR)≥60 mL/min and group II: eGFR<60mL/min].

Results:

The molar level of the transcardiac increase in NT‐pro‐BNP is lower than that of BNP. There were no differences in haemodynamics or the transcardiac gradient of BNP and NT‐pro‐BNP between group I and group II. The molar ratio of the plasma NT‐pro‐BNP to BNP was significantly higher in group II than in group I. By stepwise multivariate analyses, not only the left ventricular (LV) ejection fraction and LV end‐diastolic pressure, but also eGFR, LV mass index (LVMI) and haemoglobin were independent predictors of plasma NT‐pro‐BNP and BNP.

Conclusion:

The molar level of the transcardiac increase in NT‐pro‐BNP is lower than that of BNP; however, the influence of renal function on plasma NT‐pro‐BNP is greater than that on BNP.
Optimizing Kinase Assays for Ultrahigh-Throughput Profiling using the Kinase-Glo plus Assay
Authors: Worzella Tracy , Gallagher Aoife
Published: March 2007

Here we demonstrate the concept of kinase profiling using a panel of four kinases and 10 kinase inhibitors. We used the Kinase-Glo Plus Luminescent Kinase Assay and the Deerac Fluidics Equator HTS noncontact liquid-handling system to design and perform an ultrahigh-throughput profiling screen. We present IC50 values for each test compound and show how such profiling can streamline the initial drug discovery process.
System for Flexible Field Measurement of Physiological Data of Operators Working in Automated Labs
Authors: Stoll Regina , Kreuzfeld Steffi , Weippert Mathias , Vilbrandt Reinhard , Stoll Norbert
Published: March 2007

The strain of manual, automated, and semi-automated tasks in high-throughput chemical screening procedures offer new challenges for occupational and preventive medicine. Therefore, field inquiries need to measure several physiological parameters to determine amounts of strain. These include blood pressure, heart rate, and breathing parameters. These parameters can be registered by specialized mobile devices and sensor systems, but before they can be evaluated, it is essential to understand the activity patterns that represent the workloads. Activity status is gathered by those being tested with the help of a Nokia 3660 cell phone. A self-developed software module runs on the mobile phone and allows users to enter an activity setting and any subjective conditions via a short questionnaire. All data are stored together with a time stamp. After finishing an experiment (i.e., completing a working day), the collected data are transmitted to a central data server. Activity data and physiological data are stored in a central database in a merged data set. Access is provided via an Intranet or Internet connection. A graphical visualization tool, which can be shared from any location via Internet, helps to analyze the experimental data. Occupational medicine field studies in the working environment of chemical laboratories benefit from the data acquisition system and especially from the semiautomated self-monitoring.
Improving Workflow Efficiencies in Protein Formulation Laboratories Using Visual Basic for Applications
Authors: Ratnaswamy Gayathri , Dharmavaram Vasumathi
Published: March 2007

The protein formulation group develops stable formulations for both clinical and marketed protein therapeutics; this involves a systematic search of a large variable space. Several studies are set up each exploring the effect of a few variables at a time on protein stability. The amount of data generated from each study is substantial and is compounded as more studies are carried out. The business process from the data perspective was mapped to identify the data flow between the sub-processes. A number of redundancies in data entry that resulted in duplication of effort on the part of the researcher were identified. A custom Microsoft Excel Add-In package, using Visual Basic for Applications, has been developed in-house. To increase productivity and efficiency, at every step in the process, namely, planning, preparation, and execution and evaluation of the studies, these macros and templates allow automatic flow of information through the sub-processes. This has significantly reduced manual entry of data and errors in transcription and thereby led to savings in time and increased speed, reliability, and accuracy. Another advantage of using the macros is that the data format is standardized, facilitating the sharing of data and transfer of projects between teams. Further, metadata available through the use of the macros were used creatively to provide additional tools for overall project tracking.
Implementation of a High Specification Dual-Arm Robotic Platform to Meet Flexible Screening Needs
Authors: Moore Kevin W. , Newman Robert , Chan Grace K.Y. , Leech Clare , Allison Karen , Coulson Jo , Simpson Peter B.
Published: March 2007

The need for a high degree of flexibility within compound screening is a requirement throughout the drug discovery industry. The demands made of automation technology are becoming increasingly sophisticated as assay formats diversify and confidence in screening automation grows. To meet these demands for high-performance and flexibility, MSD with RTS Life Science have developed and installed a dual-robot arm screening system at our Terlings Park site to support early stage drug discovery. Plate transport on the system is via two articulated robotic Staubli arms. The system has two operating modes, combined, with the entire system operating in unison; and independent with each robot arm acting independently to perform two different screens in parallel. Additional flexibility is provided by the SPRINT software ‘dynamic batch scheduling’ feature. This allows for the scheduling of multiple screens to run automatically and for extra plates to be added and new screens to be added once the system is running without the need to stop the system and reschedule the work plan. The utility of the systems is exemplified in a kinase counter screening mode in which four different kinase assays are run against the same set of compounds in one robotic run.