bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low‐frequency transfer of seismic energy by superficial soil deposits and soft rocks
Authors: Mohammadioun Bagher , Pecker Alain 
Published: March 2007

AbstractRecordings of recent strong earthquakes obtained on alluvial sites show that the maximum horizontal accelerations tend towards a limit of about 0.45 to 0.50g, associated with large displacements. by contrast, vertical accelerations do not appear to be subject to such a limit (1.7g for the 1979 Imperial Valley earthquake). Theoretical linear elasticity models, when applied to superficial layers of low strength, seem to be inadequate for the prediction of near‐field ground motions in alluvial deposits. A good approximation for the horizontal component of certain Imperial Valley records was, however, obtained through a non‐linear approach, using local soil properties together with a reasonable hypothesis for motion at the base of the superficial layers in question that included large values of acceleration for high‐frequency shear waves.
Dynamic analysis of structures using lanczos co‐ordinates
Authors: Nour‐Omid Bahram , Clough Ray W. 
Published: March 2007

AbstractA procedure for deriving the Lanczos vectors is explained and their use in structural dynamics analysis as an alternative to modal co‐ordinates is discussed. The vectors are obtained by an inverse iteration procedure in which orthogonality is imposed between the vectors resulting from successive iteration cycles. Using these Lanczos vectors the equations of motion are transformed to tridiagonal form, which provides for a very efficient time‐stepping solution. The effectiveness of the method is demonstrated by a numerical example.
Dynamic eccentricity of structures subjected to S‐H waves
Authors: Wu S. T. , Leyendecker E. V. 
Published: March 2007

AbstractThe behaviour of coupled lateral‐torsional systems subjected to seismic waves is investigated analytically. This paper present numerical results of a few case studies which show the contributions of each of the selected parameters to the rotational response of the structural systems. Dynamic eccentricity is used as an index to represent the level of the rotational response. Accidental eccentricities due to S‐H waves are evaluated. Design implications based on this study are also given.
Vibrations of corner point supported shallow shells of rectangular planform
Authors: Narita Yoshihiro , Leissa Arthur W. 
Published: March 2007

AbstractThe first known solution of the title problem is presented. The Ritz method is used, with algebraic polynomials forming the set of trial functions. The condition that all three components of displacement be zero at the four corners is straightforwardly enforced. Numerical studies show that the convergence is relatively slow, requiring more terms than for shells which are completely free. The class of problems studied includes independent, constant curvature in each of the directions parallel to the edges, yielding vibration modes which fall into one of four symmetry classes, with symmetry or antisymmetry of the displacements existing with respect to each of the two symmetry axes of the problem. Detailed results are given for the frequencies and mode shapes of the first two modes of each symmetry class for shells having square planform and circular cylindrical, spherical and hyperbolic paraboloidal curvatures. Accuracy of the results is partially established by comparison with other previously published, accurate results for the corner supported flat square plate.
Modal base forces in structures having a straight‐line mode of vibration
Authors: Darbre Georges R. 
Published: March 2007

AbstractThe modal base forces in structures having a straight‐line mode of vibration are investigated. Making use of the orthogonality relationship between the different modes, a relation between the modal base shears and base moments is found in all but the straight‐line mode. This relation states that the contribution of the inertia forces to the modal overturning moments referred to the centre of rotation of the straight‐line mode is identically null. The contributions of the vertical forces and lateral constraints must, however, be accounted for. For the special case of the straight‐line mode being proportional to the height of each storey, the centre of rotation coincides with the base of the structure. For the case of the straight‐line mode being a uniform displacement, the centre of rotation is at infinity and the contribution of the inertia forces to the modal base shears identically disappears in all but the straight‐line mode.
Groundborne vibrations due to trains in tunnels
Authors: Chua K. H. , Balendra T. , Lo K. W. 
Published: April 2007

AbstractAn analytical procedure is presented for determining groundborne vibrations in buildings due to subway trains. The procedure involves a finite element idealization of the subway‐soil‐structure interaction problem, using an analytical model for the train loading spectrum at the tunnel invert. Both direct fixation and floating slab track support systems are considered. The train model is verified using the measurements of rail velocities. The proposed procedure is applied to the case of a four‐storey podium block enclosing twin double‐box subways within the confines of its ribbed wall foundations. The severity of velocity response levels of the building, in relation to vibration standards, is also considered.
Wave dispersion and optimal mass modelling for one‐dimensional periodic structures
Authors: Fukuwa Nobuo , Matsushima Shinichi 
Published: April 2007

AbstractDiscrete analysis methods are frequently used for the study of the structure and soil. However, the assumption of the displacement interpolation function makes the waves dispersive, which means the numerical dispersion. The wave dispersion induced by the discretization depends on the mass modelling. Also, the existence of added lumped masses makes waves dispersive even for the continuum modelling. In order to examine these wave dispersions, a one‐dimensional periodic structure is adopted as an analysis model and the dynamic transfer matrix method is applied. A wave solution and a finite element solution are used for the evaluation of the transfer matrix. The phase and group velocities in the structure are explicitly represented. These values are compared among the continuum modelling and the discretization modelling in which several consistent mass ratios are adopted. The optimal consistent mass ratio, which makes the wave velocity of the discrete model the same as that of the continuum model, is newly developed here. The validity of this mass modelling technique is presented by examining the frequency response function and impulse response function.
Chemical composition and antimicrobial activity of the essential oil from aerial parts of Micromeria fruticulosa (Bertol.) Grande (Lamiaceae) growing wild in Southern Italy
Authors: Formisano Carmen , Mignola Enrico , Rigano Daniela , Senatore Felice , Bellone Gabriella , Bruno Maurizio , Rosselli Sergio 
Published: April 2007

AbstractThe essential oil of aerial parts of Micromeria fruticulosa (Lamiaceae) growing wild in Southern Italy was obtained by hydrodistillation and analysed by GC and GC–MS. Sixty‐one compounds, representing 91.3% of the oil, were identified. The major components were γ‐terpinene (14.5%), β‐caryophyllene (12.6%), p‐cymene (8.9%), α‐pinene (8.2%) and β‐bisabolene (7.2%). The essential oil showed action mainly against Gram‐positive bacteria. Copyright © 2007 John Wiley & Sons, Ltd.
Diversification patterns of Early and Mid Ordovician graptolites in South China
Authors: Yuandong Zhang , Xu Chen , Goldman Daniel 
Published: March 2007

AbstractDuring the Early and Mid Ordovician, graptoloids underwent a dramatic diversification. Many clades (e.g. anisograptids, dichograptids and biserials) originated and subsequently diversified during this interval, playing the most important roles in the evolution history of graptolites. In this study we conduct an analysis of the generic and species diversity history of Early to Mid Ordovician graptolites from the Yangtze Region (platform) and Jiangnan Region (slope) of South China, and provide evidence that the regionally distinct biodiversification patterns are related to the different representative environments of each region.Graptolite diversity measured across graptolite zones displays a remarkable increase in both regions during the Early to Mid Ordovician, but with distinct scales and patterns in each region. In the Upper Yangtze Region, the diversification is less rapid and can be divided into four phases. The second major diversification phase (early Arenig) is characterized by the rapid expansion of dichograptids, and the fourth diversification phase (mid‐late Darriwilian), which is preceded by a decline (third phase), is typified by the flourishing of biserial graptolites. The diversification of graptolites in the Jiangnan Region is more dramatic and shows a distinct pattern of rapid, progressive and sustained diversity rise from the early Arenig to the early Darriwilian. This rapid diversification is initially driven by the expansion of dichograptids and subsequently enhanced by the significant addition of glossograptids and diplograptids.A comparison of diversity patterns between the Upper Yangtze Region, the Jiangnan Region, Australasia, Baltoscandia and Avalonia indicates: (1) the global Arenig expansion of dichograptids is also recorded in South China, (2) the diversity pattern of the Upper Yangtze Region is largely comparable to that of Baltoscandia and Avalonia, but is considerably different from that of Australasia, and (3) the sustained rapid increase of graptolite diversity in the Jiangnan Region is not shared by any of the other regions. Copyright © 2007 John Wiley & Sons, Ltd.
The role of patient personality in the identification of depression in older primary care patients
Authors: McCray Laura W. , Bogner Hillary R. , Sammel Mary D. , Gallo Joseph J. 
Published: April 2007

AbstractBackgroundOur aim was to evaluate whether personality factors significantly contribute to the identification of depression in older primary care patients, even after controlling for depressive symptoms.MethodsWe examined the association between personality factors and the identification of depression among 318 older adults who participated in the Spectrum study.ResultsHigh neuroticism (unadjusted Odds Ratio (OR) 2.36, 95% Confidence Interval (CI) [1.42, 3.93]) and low extraversion (adjusted OR 2.24, CI [1.26, 4.00]) were associated with physician identification of depression. Persons with high conscientiousness were less likely to be identified as depressed by the doctor (adjusted OR 0.45, CI [0.22, 0.91]).ConclusionPersonality factors influence the identification of depression among older persons in primary care over and above the relationship of depressive symptoms with physician identification. Knowledge of personality may influence the diagnosis and treatment of depression in primary care. Copyright © 2007 John Wiley & Sons, Ltd.
Phosphatidylcholine‐specific phospholipase C and ROS were involved in chicken blastodisc differentiation to vascular endothelial cells
Authors: Zhao Jing , Zhao Baoxiang , Wang Weiwei , Huang Bin , Zhang Shangli , Miao Junying 
Published: March 2007

AbstractTo find the key factors that were involved in the survival and vascular endothelial differentiation of chick blatodisc induced by fibroblast growth factor 2 (FGF‐2), we built a chick vasculogenesis model in vitro. Subsequently, the activities of phosphatidylcholine‐specific phospholipase C (PC‐PLC), including Ca2+‐dependent and ‐independent PC‐PLC, and the level of reactive oxygen species (ROS) were evaluated during the endothelial differentiation of chick blastodisc. The results showed that Ca2+‐indepentent PC‐PLC underwent a remarkable increase in 24 h (P < 0.01), then it decreased gradually with the cell differentiation, while the Ca2+‐depentent PC‐PLC was nearly not changed in the whole process. At the same time, ROS level dramatically decreased during the cell differentiation. To understand the role of PC‐PLC and how it performs its function in the vascular endothelial differentiation induced by FGF‐2, we suppressed PC‐PLC activity by its specific inhibitor D609 (tricyclodecan‐9‐yl potassium xanthate) at 24 h during the cell differentiation. As a result, the cell differentiation could not progress and the intracellular level of ROS was elevated. The data suggested that PC‐PLC and ROS were involved in chicken blastodisc differentiation to vascular endothelial cells. PC‐PLC was an important factor in the blastodisc cell survival and differentiation, and it might perform its function associated with ROS. J. Cell. Biochem. 102: 421–428, 2007. © 2007 Wiley‐Liss, Inc.
Progesterone induces Apoptosis in TRAIL‐resistant ovarian cancer cells by circumventing c‐FLIPL overexpression
Authors: Syed Viqar , Mukherjee Kasturi , Godoy‐Tundidor Sonia , Ho Shuk‐Mei 
Published: March 2007

AbstractTumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) holds great potential as an anticancer drug, since it induces selective cell death in cancer cells but not in normal ones. However, cancer cells often acquire resistance to TRAIL, which hinders its clinical efficacy. We previously demonstrated that progesterone triggers apoptosis in human ovarian cancer (OCa) cells. In the present study, we evaluated the prospect of utilizing progestins in combination with TRAIL to enhance cell death in TRAIL‐sensitive (OVCA 420, OVCA 429, and OVCA 433) and ‐resistant (OVCA 432) OCa cell lines. TRAIL sensitivity (60–80% cell kill) bore no correlation with expression of the TRAIL receptors (DR4, DR5) or their decoys (DcR1 and DcR2), but was associated with activation of caspase‐8 and ‐3, and downregulation of the long isoform of FLICE‐like inhibitory protein (c‐FLIPL), an anti‐apoptosis mediator. Small interfering RNA‐mediated knockdown of c‐FLIPL expression restored TRAIL sensitivity in OVCA 432 cells. Induction of c‐FLIPL overexpression increased TRAIL resistance in TRAIL‐sensitive lines. Thus, persistent high level of c‐FLIPL expression likely mediates TRAIL resistance in OCa cells. Treatment of OCa cells with progesterone enhanced TRAIL‐induced cell death (>85%), but only in TRAIL‐sensitive cell lines. Combined treatment with two progestins was superior to single progestin treatment, with progesterone plus medroxyprogesterone acetate (MPA) achieving over 85% cell kill in both TRAIL‐sensitive and ‐resistant OCa cell lines. Significantly, unlike TRAIL, progestin‐induced cell death did not involve c‐FLIPL downregulation. Hence, combined progestin regimens, with or without TRAIL, may serve as an effective therapy for OCa by circumventing the anti‐apoptotic action of c‐FLIPL. J. Cell. Biochem. 102: 442–452, 2007. © 2007 Wiley‐Liss, Inc.
Two‐photon lifetime imaging of fluorescent probes in intact blood vessels: A window to sub‐cellular structural information and binding status
Authors: Douma Kim , Megens Remco T.A. , Reitsma Sietze , Prinzen Lenneke , Slaaf Dick W. , Van Zandvoort Marc A.M.J. 
Published: March 2007

AbstractFluorescence lifetime imaging (FLIM) provides a complementary contrast mechanism to fluorescence intensity and ratio imaging in intact tissue. With FLIM the time‐resolved decay in fluorescence intensity of (interacting) fluorophores can be quantified by means of time correlated single photon counting (TCSPC). Here we focus on fluorescence lifetime imaging in intact blood vessels. Requisites for imaging in intact tissue are good penetration depth and limited tissue damage. Therefore, in this pilot‐study, we performed TCSPC‐FLIM using two‐photon laser scanning microscopy to determine, with sub‐cellular resolution, the fluorescence lifetime of two fluorescent probes. First, we focused on the nucleic acid dye SYTO41 in the various compartments of cells in vitro and in situ in the wall of intact mouse carotid arteries. Second, it was assessed whether the interaction of the lectin WGA‐FITC with the endothelial glycocalyx affects its fluorescence lifetime. Results showed comparable mono‐exponential fluorescence lifetimes of SYTO41 in the nuclei of cells in vitro and in situ. The slightly shorter fluorescence lifetime observed in the cytoplasm allowed discrimination of the nuclei. SYTO41 displayed strong mitochondrial staining, as was verified by the mitochondrion‐specific probe CMXRos. In addition, mitochondrial staining by SYTO41 was accompanied by a green shift in emission. In the mitochondrial region, SYTO41 showed a highly bi‐exponential and relatively fast decay, with two distinct lifetime components. It is hypothesized that the fitted bi‐exponential decay can either be contributed to (1) the mathematical approximation of the fluorescence intensity decay or (2) the presence of free and DNA‐bound SYTO41 in the mitochondrial compartment, leading to two lifetime components. The fluorescence lifetime of WGA‐FITC decreased by ∼25% upon binding to the endothelial glycocalyx. From this study, we conclude that FLIM offers an additional contrast mechanism in imaging intact tissue and provides information on binding status between a probe and its ligand. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Towards metabolic mapping of the human retina
Authors: Schweitzer D. , Schenke S. , Hammer M. , Schweitzer F. , Jentsch S. , Birckner E. , Becker W. , Bergmann A. 
Published: March 2007

AbstractFunctional alterations are first signs of a starting pathological process. A device that measures parameter for the characterization of the metabolism at the human eye‐ground would be a helpful tool for early diagnostics in stages when alterations are yet reversible. Measurements of blood flow and of oxygen saturation are necessary but not sufficient. The new technique of auto‐fluorescence lifetime measurement (FLIM) opens in combination with selected excitation and emission ranges the possibility for metabolic mapping. FLIM not only adds an additional discrimination parameter to distinguish different fluorophores but also resolves different quenching states of the same fluorophore. Because of its high sensitivity and high temporal resolution, its capability to resolve multi‐exponential decay functions, and its easy combination with laser scanner ophthalmoscopy, multi‐dimensional time‐correlated single photon counting was used for fundus imaging. An optimized set up for in vivo lifetime measurements at the human eye‐ground will be explained. In this, the fundus fluorescence is excited at 446 or 468 nm and the time‐resolved autofluorescence is detected in two spectral ranges between 510 and 560 nm as well as between 560 and 700 nm simultaneously. Exciting the fundus at 446 nm, several fluorescence maxima of lifetime t1 were detected between 100 and 220 ps in lifetime histograms of 40° fundus images. In contrast, excitation at 468 nm results in a single maximum of lifetime t1 = 190 ± 16 ps. Several fundus layers contribute to the fluorescence intensity in the short‐wave emission range 510–560 nm. In contrast, the fluorescence intensity in the long‐wave emission range between 560 and 700 nm is dominated by the fluorescence of lipofuscin in the retinal pigment epithelium. Comparing the lateral distribution of parameters of a tri‐exponential model function in lifetime images of the fundus with the layered anatomical fundus structure, the shortest component (t1 = 190 ps) originates from the retinal pigment epithelium and the second lifetime (t2 = 1,000 ps) from the neural retina. The lifetime t3 ≈ 5.5 ns might be influenced by the long decay of the fluorescence in the crystalline lens. In vitro analysis of the spectral properties of expected fluorophores under the condition of the living eye lightens the interpretation of in vivo measurements. Taking into account the transmission of the ocular media, the excitation of NADH is unlikely at the fundus. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Simultaneous two‐photon fluorescence correlation spectroscopy and lifetime imaging of dye molecules in submicrometer fluidic structures
Authors: Petrášek Zdeněk , Krishnan Madhavi , Mönch Ingolf , Schwille Petra 
Published: March 2007

AbstractFluorescence correlation spectroscopy (FCS) is a very sensitive technique that can be used, e.g., for the measurement of low concentrations and for the investigation of transport of fluorescent molecules. Fluorescence lifetime imaging (FLIM) provides spatially resolved information about molecular fluorescence lifetimes reflecting the interactions of the molecules with their environment. We have applied simultaneous two‐photon FCS and FLIM to probe the behavior of fluorescent molecules diffusing in submicrometer silicon oxide channels. Our measurements reveal differences in fluorescence lifetimes compared to bulk solution that result from the effects of confinement and the presence of interfaces. Confinement also affects diffusional characteristics of fluorophores as reflected in fluorescence autocorrelation functions. These possible consequences of both spatial confinement and the presence of interfaces between media with different refractive indices on the diffusion and fluorescence lifetime of molecules in nanostructures are discussed in general. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Fluorescence detection with high time resolution: From optical microscopy to simultaneous force and fluorescence spectroscopy
Authors: Gaiduk Alexander , Kühnemuth Ralf , Felekyan Suren , Antonik Matthew , Becker Wolfgang , Kudryavtsev Volodymyr , Sandhagen Carl , Seidel Claus A.M. 
Published: March 2007

AbstractPicosecond time‐resolution fluorescence signal detection over many hours is possible using the time‐correlated single photon counting (TCSPC) technique. Advanced TCSPC with clock oscillator set by the pulsed laser and data analysis provides a tool to investigate processes in single molecules on time scale from picoseconds to seconds. Optical imaging techniques combined with TCSPC allow one to study the spatial distribution of fluorescence properties in solution and on a surface. Mechanical manipulation of a single macromolecule by means of an atomic‐force microscope makes it possible to detect fluorescence signal changes as a function of mechanical conformations of a fluorescent dye attached to a single DNA molecule. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Multi‐dimensional fluorescence lifetime and FRET measurements
Authors: Biskup Christoph , Zimmer Thomas , Kelbauskas Laimonas , Hoffmann Birgit , Klöcker Nikolaj , Becker Wolfgang , Bergmann Axel , Benndorf Klaus 
Published: March 2007

AbstractWhen and where proteins associate with each other in living cells are key questions in many biological research projects. One way to address these questions is to measure the extent of Förster resonance energy transfer (FRET) between proteins that have been labeled with appropriate donor and acceptor fluorophores. When both proteins interact, donor and acceptor fluorophores are brought into close vicinity so that the donor can transmit a part of its excitation energy to the acceptor. As a result, both the intensity and the lifetime of the donor fluorescence decrease, whereas the intensity of the acceptor emission increases. This offers different approaches to determine FRET efficiency: One is to detect changes in the intensity of donor and acceptor emission, the other is to measure changes in the lifetime of the donor molecule. One important advantage of the fluorescence lifetime approach is that it allows to distinguish between free and associated donor molecules. However, like intensity measurements it lacks an intrinsic control ensuring that changes in the measured parameters are only due to FRET and not other quenching processes. Here, we show how this limitation can be overcome by spectrally resolved fluorescence lifetime measurements in the time domain. One technique is based on a streak camera system, the other technique is based on a time‐correlated‐single‐photon‐counting approach. Both approaches allow biologists to record both donor and acceptor fluorescence emitted by the sample in a single measurement. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.