bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seismic response of base‐isolated structures with vertical‐rocking coupling
Authors: Pan Tso‐Chien , Kelly James M. 
Published: March 2007

AbstractA base‐isolated building is liable to have a small horizontal eccentricity between the centre of mass of the superstructure and the centre of rigidity of the supporting bearings. In seismic analysis, the structure is modelled as a rigid block with tributary masses supported on massless elastomeric rubber bearings placed at a constant elevation below the centre of mass. This simplified system has three degrees of freedom: two translations and one rotation in the vertical plane.The investigation of the dynamic behaviour of a base‐isolated building is carried out for both the detuned and the perfectly tuned cases. In the detuned case, the natural frequencies of the system are assumed to be well separated. In the perfectly tuned case, the uncoupled rocking frequency is assumed to be identical to the vertical translational frequency, which may result from an unusual mass distribution and/or an extreme aspect ratio of the superstructure. Perturbation methods are implemented in finding the dynamic characteristics for both cases. However, the dynamic response of the perfectly tuned case is the major concern in this investigation.The Green's functions for the displacement response of the three‐degree‐of‐freedom system are derived for both the undamped and damped conditions. The response spectrum modal superposition method is used in estimating the maximum acceleration response. A simple method, accounting for the effect of closely spaced modes, is proposed for combining modal maxima and results in an approximate solution corresponding to a single‐degree‐of‐freedom system. This approximate solution may be used for the preliminary design of a base‐isolated structure.Numerical results for a base‐isolated building subjected to the vertical component of the El Centro earthquake of 1940 were carried out for comparison with these analytical results. The proposed modal combination method showed superiority over the conventional Square Root of the Sum of the Squares method in estimating maximum responses. The results also indicated that the approximate single‐degree‐of‐freedom system yields accurate estimations.It is shown that the effect of rocking coupling on the vertical response of base‐isolated structures subjected to transient loadings, such as earthquake motions, can generally be neglected as a result of the combined effects of the time lag between the maximum translational and rotational responses and the influence of damping in the isolation system, which for elastomeric bearings can be as high as 8 to 10 per cent of critical.
Dynamic performance analysis of novel unified power flow controller with computer simulation and scaled‐model experiment
Authors: Han Byung M. , Ledwich Gerard 
Published: March 2007

AbstractThis paper describes dynamic performance analysis of Unified Power Flow Controller (UPFC) composed of cascaded H‐bridge and single‐phase multi‐winding transformers for isolation. The operational characteristic was analyzed through simulations with PSCAD/EMTDC, and experimental works with a scaled model. The UPFC proposed in this paper can be directly connected to the transmission line without series injection transformers. It has flexibility to expand the operation voltage by increasing the number of H‐bridges. Copyright © 2007 John Wiley & Sons, Ltd.
Nuclear actin is involved in the regulation of CSF1 gene transcription in a chromatin required, BRG1 independent manner
Authors: Song Zhaoxia , Wang Min , Wang Xiaoguang , Pan Xuefang , Liu Wenguang , Hao Shui , Zeng Xianlu 
Published: March 2007

AbstractActin is an important protein in nucleus and has been implicated in transcription, however, the mechanism of its function in transcription is still not clear. In this article, we studied the role of actin in the regulation of human CSF1 gene transcription. Our results showed that nuclear actin stimulates the activity of CSF1 promoter, and the role in augmenting CSF1 gene transcription requires the formation of chromatin and Z‐DNA structure. The ATP binding motifs of nuclear actin are essential for its function in regulating CSF1 gene transcription, and upon actin overexpression, there is an increase in the ATPase activity of nuclear proteins. Further investigation revealed that nuclear actin regulates CSF1 gene transcription in a BRG1 independent manner. Together, these original results have provided evidence for further understanding the mechanism of nuclear actin in regulating gene transcription. J. Cell. Biochem. 102: 403–411, 2007. © 2007 Wiley‐Liss, Inc.
Multispectral fluorescence lifetime imaging by TCSPC
Authors: Becker Wolfgang , Bergmann Axel , Biskup Christoph 
Published: March 2007

AbstractWe present a fluorescence lifetime imaging technique with simultaneous spectral and temporal resolution. The technique is fully compatible with the commonly used multiphoton microscopes and nondescanned (direct) detection. An image of the back‐aperture of the microscope lens is projected on the input of a fiber bundle. The input of the fiber bundle is circular, and the output is flattened to match the input slit of a spectrograph. The spectrum at the output of the spectrograph is projected on a 16‐anode PMT module. For each detected photon, the encoding logics of the PMT module deliver a timing pulse and the number of the PMT channel in which the photon was detected. The photons are accumulated by a multidimensional time‐correlated single photon counting (TCSPC) process. The recording process builds up a four‐dimensional photon distribution over the times of the photons in the excitation pulse period, the wavelengths of the photons, and the coordinates of the scan area. The method delivers a near‐ideal counting efficiency and is capable of resolving double‐exponential decay functions. We demonstrate the performance of the technique for autofluorescence imaging of tissue. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Ultrastructure of the Male Reproductive System of Cotesia vestalis (Hymenoptera: Braconidae) with Preliminary Characterization of the Secretions
Authors: Huang Fang , Yu Rui‐Xian , Chen Xue‐Xin 
Published: March 2007

AbstractThe morphology and ultrastructure of testes and accessory glands along with the characterization of their secretions were investigated for a braconid species Cotesia vestalis (Hymenoptera: Braconidae) using light and electron microscopes. The male internal reproductive system of this species is distinguished by a pair of testes, one vas deferens, and a pair of male accessory glands. The testes are separate, and the accessory glands are oval and not fused. It was observed that the secretory cells of testes have characteristic smooth and rough endoplasmic reticulum, and that the cytoplasm is filled with an array of granule droplets usually of two to three types. The secretory cells in the case of accessory glands are typified by the presence of microvilli on their apical cell surfaces and numerous mitochondria in their cytoplasm. SDS‐PAGE profile when performed depicted a similarity in most bands of the secretions from both testes and accessory glands, except for four proteins of which two were present only in testes, while the other two only appeared in accessory glands. Their molecular weights were 117 and 55 kDa for testes and 196 and 30 kDa for accessory glands, respectively. This study gives new insights into the intriguing features of male internal reproductive system and it especially constitutes the first report of its kind about the secretion properties of these organs in C. vestalis. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
FRET measurements on fuzzy fluorescent nanostructures
Authors: Caorsi V. , Ronzitti E. , Vicidomini G. , Krol S. , McConnell G. , Diaspro A. 
Published: March 2007

AbstractIn the last decade, fluorescence resonance energy transfer (FRET) has become a useful technique for studying intermolecular interactions applied to the analysis of biological systems. Although FRET measurements may be very helpful in the comprehension of different cellular processes, it can be difficult to obtain quantitative results, hence the necessity of studying FRET on controllable systems. Here, a fuzzy nanostructured system called a nanocapsule is presented as a nanometric‐device allowing distance modulation, thus preserving photophysical properties of fluorescent dyes and exhibiting good potential features for improving quantitative FRET analysis. We evaluated the behavior of such a sample using four FRET methods (three of them based on steady‐state fluorescence and one using lifetime measurements). Within some limitations that can be overcome, these nanodevices have the potential to serve as a benchmark system for characterizing new FRET couples and to develop quantitative approaches for FRET analysis. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Accumulation of Triosephosphate Isomerase, with Sequence Homology to β Amyloid Peptides, in Vessel Walls of the Newborn Piglet Hippocampus
Authors: Kusaka Takashi , Ueno Masaki , Miki Takanori , Kanenishi Kenji , Nagai Yukiko , Huang Cheng‐Long , Okamoto Yasuo , Ogawa Takafumi , Onodera Masayuki , Itoh Susumu , Akiguchi Ichiro , Sakamoto Haruhiko 
Published: March 2007

AbstractWe investigated whether β‐amyloid (Aβ)‐like immunoreactivity was seen in the brains of newborn piglets. The immunoreactivity for Aβ(1‐42) and Aβ(1–40) proteins, but not Aβ precursor protein, was present in CD68‐positive perivascular cells of the hippocampus and in parts of the meninges. It was colocalized with immunoreactivity for receptor for advanced glycation end product and tumor necrosis factor‐α. The protein with a molecular mass of 27 kDa, which was recognized by the Aβ antibodies, was identified as triosephosphate isomerase (TPI) with sequence homology to Aβ peptides by N‐terminal amino acid sequencing, mass fingerprint analysis using matrix‐associated laser desorption/ionization mass spectrometry, and Western blotting. Western blotting assay also revealed that detectable expression of Aβ proteins were not seen in the piglet brains. These findings indicate that TPI with sequence homology to Aβ peptides accumulates in perivascular cells of the microglia/macrophage lineage located around arterial vessels of the newborn piglet hippocampus. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Raman Microscopy of Freeze‐dried Mouse Eyeball‐slice in Conjunction with the “in vivo Cryotechnique”
Authors: Terada Nobuo , Ohno Nobuhiko , Saitoh Sei , Fujii Yasuhisa , Ohguro Hiroshi , Ohno Shinichi 
Published: March 2007

AbstractThe wavelength of Raman‐scattered light depends on the molecular composition of the substance. This is the first attempt to acquire Raman spectra of a mouse eyeball removed from a living mouse, in which the eyeball was preserved using the “in vivo cryotechnique” followed by freeze‐drying. Eyeballs were cryofixed using a rapid freezing cryotechnique, and then sliced in the cryostat machine. The slices were sandwiched between glass slides, freeze‐dried, and analyzed with confocal Raman microscopy. Important areas including various eyeball tissue layers were selected using bright‐field microscopy, and then the Raman spectra were obtained at 240 locations. Four typical patterns of Raman spectra were electronically mapped on the specimen images obtained by the bright‐field microscopy. Tissue organization was confirmed by embedding the same eyeball slice used for Raman spectra into epoxy resin and the thick sections were prepared with the inverted capsule method. Each Raman spectral pattern represents a different histological layer in the eyeball which was mapped by comparing the images of toluidine blue staining and Raman mapping with different colors. In the choroid and pigment cell layer, the Raman spectrum had two peaks, corresponding to melanin. Some of the peaks of the Raman spectra obtained from the blood vessels in sclera and the photoreceptor layer were similar to those obtained from the purified hemoglobin and rhodopsin proteins, respectively. Our experimental protocol can distinguish different tissue components with Raman microscopy; therefore, this method can be very useful for examining the distribution of a biological structures and/or chemical components in rapidly frozen freeze‐dried tissue. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Fluorescence intensity is a poor predictor of saturation effects in two‐photon microscopy: Artifacts in fluorescence correlation spectroscopy
Authors: Wu Jianrong , Berland Keith 
Published: March 2007

AbstractFluorescence correlation spectroscopy (FCS) has become an increasingly important measurement tool for biological and biomedical investigations, with the capability to assay molecular dynamics and interactions both in vitro and within living cells. Information recovery in FCS requires an accurate characterization and calibration of the observation volume. A number of recent reports have demonstrated that the calibration of the observation volume is excitation power dependent, a complication that arises due to excitation saturation. While quantitative models are now available to account for these volume variations, many researchers attempt to avoid saturation issues by working with low nonsaturating excitation intensities. For two‐photon excited fluorescence, this is typically thought to be achievable by working with excitation powers for which the total measured fluorescence signal maintains its quadratic dependence on excitation intensity. We demonstrate that observing only the power dependence of the fluorescence intensity will tend to underestimate the importance of saturation, and explain these findings in terms of basic physical models. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Fluorescence microscopy: Established and emerging methods, experimental strategies, and applications in immunology
Authors: Petty Howard R. 
Published: March 2007

AbstractCutting‐edge biophysical technologies including total internal reflection fluorescence microscopy, single molecule fluorescence, single channel opening events, fluorescence resonance energy transfer, high‐speed exposures, two‐photon imaging, fluorescence lifetime imaging, and other tools are becoming increasingly important in immunology as they link molecular events to cellular physiology, a key goal of modern immunology. The primary concern in all forms of microscopy is the generation of contrast; for fluorescence microscopy contrast can be thought of as the difference in intensity between the cell and background, the signal‐to‐noise ratio. High information‐content images can be formed by enhancing the signal, suppressing the noise, or both. As improved tools, such as ICCD and EMCCD cameras, become available for fluorescence imaging in molecular and cellular immunology, it is important to optimize other aspects of the imaging system. Numerous practical strategies to enhance fluorescence microscopy experiments are reviewed. The use of instrumentation such as light traps, cameras, objectives, improved fluorescent labels, and image filtration routines applicable to low light level experiments are discussed. New methodologies providing resolution well beyond that given by the Rayleigh criterion are outlined. Ongoing and future developments in fluorescence microscopy instrumentation and technique are reviewed. This review is intended to address situations where the signal is weak, which is important for emerging techniques stressing super‐resolution or live cell dynamics, but is less important for conventional applications such as indirect immunofluorescence. This review provides a broad integrative discussion of fluorescence microscopy with selected applications in immunology. Microsc. Res. Tech., 2007. © 2007 Wiley‐Liss, Inc.
Development management—values and partnerships
Authors: Thomas Alan 
Published: March 2007

AbstractValues and multi‐organization partnerships are two crucial aspects of the contested field of development management. Their management crucially involves questions of authority, accountability, agency and validity. This Policy Arena includes two pairs of papers, one addressing the management of values and partnerships respectively in the context of NGOs and the second pair doing the same with respect to development management more broadly. They show that partnerships and values have in common that they cannot be managed by the imposition of a rationally defined programme of action but require indirect approaches such as steering, negotiation and looking for common ground. Copyright © 2007 John Wiley & Sons, Ltd.
Prions and peripheral nerves: A deadly rendezvous
Authors: Heikenwalder Mathias , Julius Christian , Aguzzi Adriano 
Published: March 2007

AbstractThe infectious particle causing transmissible spongiform encephalopathy (TSE), a fatal neurodegenerative disease of humans and animals, has been termed prion. Its major component is an aggregated variant of the cellular prion protein, PrPC. The main target of prion pathology is the central nervous system (CNS), yet most prion diseases are initiated or accompanied by prion replication at extracerebral locations, including secondary lymphoid organs, muscle and, in some instances, blood. How do prions travel from the periphery into the CNS? Is this an active or a passive process and does neuronal prion transport explain the long incubation times in prion diseases? Alternatively, if prion infectivity arises spontaneously in the CNS, as believed from sporadic Creutzfeldt‐Jakob patients, how do prions manage to travel from the CNS into the periphery (e.g., spleen, muscle) of the infected host? The mechanisms of neuronal prion transport from the periphery into the CNS or vice versa are heavily investigated and debated but poorly understood. Although research in the past has accumulated knowledge on prion progression from the periphery to the brain, we are far from understanding the molecular mechanisms of neuronal prion transport. © 2007 Wiley‐Liss, Inc.
Swedish amyloid precursor protein mutation increases phosphorylation of eIF2α in vitro and in vivo
Authors: Kim Hye‐Sun , Choi Yoori , Shin Ki‐Young , Joo Yuyoung , Lee Yong‐Kyu , Jung Sang Yong , Suh Yoo‐Hun , Kim Joung‐Hun 
Published: March 2007

AbstractSwedish double mutation (KM670/671NL) of amyloid precursor protein (Swe‐APP), a prevailing cause of familial Alzheimer's disease (FAD), is known to increase in Aβ production both in vitro and in vivo, but its underlying molecular basis leading to Alzheimer's disease (AD) pathogenesis remains to be elucidated, especially for the early phase of disease. We have confirmed initially that the expression of Swe‐APP mutant transgene reduced cell viability via ROS production but this effect was eliminated by an anti‐oxidative agent, vitamin E. We also found that eukaryotic translation initiation factor‐2α (eIF2α), which facilitates binding of initiator tRNA to ribosomes to set on protein synthesis, was phosphorylated in cultured cells expressing Swe‐APP. This increase in phosphorylated eIF2α was also attenuated significantly by treatment with vitamin E. The finding that eIF2α became highly phosphorylated by increased production of Aβ was substantiated in brain tissues of both an AD animal model and AD patients. Although an increase in Aβ production would result in cell death eventually (in late‐phase of the disease), the altered phosphorylation state of eIF2α evoked by Aβ may account for the decreased efficacy of mRNA translation and de novo protein synthesis required for synaptic plasticity, and may consequently be one of molecular causes for impairment of cognitive functions exhibited in the early phase of AD patients. © 2007 Wiley‐Liss, Inc.
Interactions between neural membrane glycerophospholipid and sphingolipid mediators: A recipe for neural cell survival or suicide
Authors: Farooqui Akhlaq A. , Horrocks Lloyd A. , Farooqui Tahira 
Published: March 2007

AbstractThe neural membranes contain phospholipids, sphingolipids, cholesterol, and proteins. Glycerophospholipids and sphingolipids are precursors for lipid mediators involved in signal transduction processes. Degradation of glycerophospholipids by phospholipase A2(PLA2) generates arachidonic acid (AA) and docosahexaenoic acids (DHA). Arachidonic acid is metabolized to eicosanoids and DHA is metabolized to docosanoids. The catabolism of glycosphingolipids generates ceramide, ceramide 1‐phosphate, sphingosine, and sphingosine 1‐phosphate. These metabolites modulate PLA2activity. Arachidonic acid, a product derived from glycerophospholipid catabolism by PLA2, modulates sphingomyelinase (SMase), the enzyme that generates ceramide and phosphocholine. Furthermore, sphingosine 1‐phosphate modulates cyclooxygenase, an enzyme responsible for eicosanoid production in brain. This suggests that an interplay and cross talk occurs between lipid mediators of glycerophospholipid and glycosphingolipid metabolism in brain tissue. This interplay between metabolites of glycerophospholipid and sphingolipid metabolism may play an important role in initiation and maintenance of oxidative stress associated with neurologic disorders as well as in neural cell proliferation, differentiation, and apoptosis. Recent studies indicate that PLA2and SMase inhibitors can be used as neuroprotective and anti‐apoptotic agents. Development of novel inhibitors of PLA2and SMase may be useful for the treatment of oxidative stress, and apoptosis associated with neurologic disorders such as stroke, Alzheimer disease, Parkinson disease, and head and spinal cord injuries. © 2007 Wiley‐Liss, Inc.
Modulation of normal and altered hippocampal excitability states by septal networks
Authors: Colom Luis V. , Garrido‐Sanabria Emilio 
Published: March 2007

AbstractThe septal region of the basal forebrain plays a dual role: 1) It modulates hippocampal excitability, facilitating synaptic plasticity within hippocampal circuits. Through this mechanism, the septum facilitates diverse cognitive processes that involve hippocampal circuits. 2) Additionally, the septum maintains the hippocampal networks working within normal ranges, decreasing the probability of abnormal excitability states. Through this second mechanism, the septum prevents the occurrence of epileptic discharges. Thus, septal alterations may lead to both decreased cognitive functions and epilepsy, as observed in elderly patients affected with Alzheimer's disease. © 2007 Wiley‐Liss, Inc.
Nutrient dynamics—wind and water erosion at the village scale in the Sahel
Authors: Visser S. M. , Sterk G. 
Published: March 2007

AbstractThe loss of nutrients by wind erosion is generally attributed to losses by suspension, since suspension selectively removes the finest particles. However, because the main mass of sediment is moved by saltation during an event, the main mass of nutrients is also moved by saltation. Nutrient losses from one field during one wind erosion event can be as high as 73 per cent of the N and 100 per cent of the P needs for crop production.Vegetated areas have a higher dust deposition because of the filtering effect of the vegetation and the reduction of drag forces causing a higher deposition. This refutes the general assumption that deposition of suspended dust is homogeneous for a larger area. In the Sahel, two types of dust can be distinguished, the Harmattan dust is richer in nutrients and regarded as a real input of nutrients. The convectional storm dust has a nutrient content comparable with the nutrient content of the dust fraction of the topsoil and can't be regarded as input of nutrients.From research on nutrient losses by water erosion at the plot scale, it is concluded that nutrient erosion by water can cause serious losses of nutrients. But at the village scale, the losses are considerably smaller than at the plot scale.Measurement and subsequent nutrient budget analyses around the village Dangadé in Burkina Faso indicated that this area is especially vulnerable for wind erosion by saltation transport. This demonstrates that in the Sahelian environment, the effect of wind erosion at the village scale can't be ignored. Copyright © 2007 John Wiley & Sons, Ltd.