bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microemulsion and micellar electrokinetic chromatography of Hematoporphyrin D: A starting material of hematoporphyrin derivative
Authors: Li Qi , Chang C. K. , Huie Carmen W. 
Published: January 2005

AbstractAn investigation of the basic factors which govern the microemulsion electrokinetic chromatography (MEEKC) and micellar electrokinetic chromatography (MEKC) separation of Hematoporphyrin D and its base hydrolysis product, hematoporphyrin derivative (HpD), was performed. These model compounds contain a complex mixture of porphyrin monomers, dimers and/or oligomers, and were utilized to gain insights into the MEEKC/micellar electrokinetic chromatography (MEKC) separation of samples containing highly lipophilic substances. For example, the organic modifier/cosurfactant (1‐butanol) and/or oil phase (e.g., 1‐octanol in comparison to ethyl acetate) were found to have an apparent influence on the separation selectivity of Hematoporphyrin D, the extent of which was dependent on the chemical nature of the surfactant employed (e.g., sodium dodecyl sulfate vs. sodium cholate). An interesting and important finding was that the presence of an organic modifier (methanol or acetonitrile at a concentration of 20% or higher) in the sample matrix as well as in the run buffer was essential for the optimal MEEKC or MEKC separation of a number of porphyrin monomers (including hematoporphyrin IX and its acetates, most likely hydroxyacetate, diacetate, and vinyl acetate, as well as its dehydration products, hydroxyethylvinyldeuteroporphyrin and protoporphyrin) contained in Hematoporphyrin D. On the other hand, the use of these optimized conditions for the MEEKC or MEKC separation of various oligomeric porphyrin species in HpD were unsatisfactory. As HpD is a well‐known and effective photosensitizing agent in photodynamic therapy (a new approach for cancer treatment), the improved separation and characterization of various monomeric and oligomeric porphyrin species in HpD and its starting material, such as Hematoporphyrin D, is a challenging and important task.
How Fanconi anemia proteins promote the four Rs: Replication, recombination, repair, and recovery
Authors: Thompson Larry H. , Hinz John M. , Yamada N. Alice , Jones Nigel J. 
Published: January 2005

AbstractThe genetically complex disease Fanconi anemia (FA) comprises cancer predisposition, developmental defects, and bone marrow failure due to elevated apoptosis. The FA cellular phenotype includes universal sensitivity to DNA crosslinking damage, symptoms of oxidative stress, and reduced mutability at the X‐linked HPRT gene. In this review article, we present a new heuristic molecular model that accommodates these varied features of FA cells. In our view, the FANCA, ‐C, and ‐G proteins, which are both cytoplasmic and nuclear, have an integrated dual role in which they sense and convey information about cytoplasmic oxidative stress to the nucleus, where they participate in the further assembly and functionality of the nuclear core complex (NCCFA = FANCA/B/C/E/F/G/L). In turn, NCCFA facilitates DNA replication at sites of base damage and strand breaks by performing the critical monoubiquitination of FANCD2, an event that somehow helps stabilize blocked and broken replication forks. This stabilization facilitates two kinds of processes: translesion synthesis at sites of blocking lesions (e.g., oxidative base damage), which produces point mutations by error‐prone polymerases, and homologous recombination‐mediated restart of broken forks, which arise spontaneously and when crosslinks are unhooked by the ERCC1‐XPF endonuclease. In the absence of the critical FANCD2 monoubiquitination step, broken replication forks further lose chromatid continuity by collapsing into a configuration that is more difficult to restart through recombination and prone to aberrant repair through nonhomologous end joining. Thus, the FA regulatory pathway promotes chromosome integrity by monitoring oxidative stress and coping efficiently with the accompanying oxidative DNA damage during DNA replication. Environ. Mol. Mutagen., 2005. Published 2005 Wiley‐Liss, Inc.
Molecular nature of intrachromosomal deletions and base substitutions induced by environmental mutagens
Authors: Nohmi Takehiko , Masumura Ken‐ichi 
Published: January 2005

AbstractCellular DNA is exposed to a variety of exogenous and endogenous mutagens. A complete understanding of the importance of different types of DNA damage requires knowledge of the specific molecular alterations induced by different types of agents in specific target tissues in vivo. The gpt delta transgenic mouse model provides the opportunity to characterize tissue‐specific DNA alterations because small and large deletions as well as base substitutions can be analyzed. Here, we summarize the characteristics of intrachromosomal deletions and base substitutions induced by ionizing radiation in liver and spleen, ultraviolet B (UVB) radiation in epidermis, mitomycin C (MMC) in bone marrow, 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine (PhIP) in colon, and aminophenylnorharman (APNH) in liver of gpt delta mice. Carbon‐ion radiation, UVB, and MMC induced large deletions of more than 1 kb. About half of the large deletions occurred between short direct‐repeat sequences and the remainder had flush ends, suggesting the involvement of nonhomologous end joining of double‐stranded breaks (DSBs) in DNA. UV photoproducts and interstrand crosslinks by MMC may block DNA replication, thereby inducing DSBs. In contrast, PhIP and APNH mainly generated 1 bp deletions in runs of guanine bases. As for base substitutions, UVB and MMC induced G:C→A:T transitions at dipyrimidine sites and tandem base substitutions at GG sites, respectively. PhIP and APNH induced G:C→T:A transversions. Translesion DNA synthesis across the lesions, i.e., UV photoproducts, intrastrand crosslinks by MMC, and guanine adducts by the heterocyclic amines, may be involved in the induction of base substitutions. These results indicate the importance of sequence information to elucidate the mechanisms underlying deletions and base substitutions induced in vivo by environmental mutagens. Environ. Mol. Mutagen., 2005. © 2005 Wiley‐Liss, Inc.
A reduced‐order modeling technique for tall buildings with active tuned mass damper
Authors: Qu Zu‐Qing , Shi Yinming , Hua Hongxing 
Published: January 2005

AbstractIt is impractical to install sensors on every floor of a tall building to measure the full state vector because of the large number of degrees of freedom. This makes it necessary to introduce reduced‐order control. A kind of system reduction scheme (dynamic condensation method) is proposed in this paper. This method is iterative and Guyan condensation is looked upon as an initial approximation of the iteration. Since the reduced‐order system is updated repeatedly until a desired one is obtained, the accuracy of the reduced‐order system resulting from the proposed method is much higher than that obtained from the Guyan condensation method. Another advantage of the method is that the reduced‐order system is defined in the subspace of the original physical space, which makes the state vectors have physical meaning. An eigenvalue shifting technique is applied to accelerate the convergence of iteration and to make the reduced system retain all the dynamic characteristics of the full system within a given frequency range. Two schemes to establish the reduced‐order system by using the proposed method are also presented and discussed in this paper. The results for a tall building with active tuned mass damper show that the proposed method is efficient for the reduced‐order modelling and the accuracy is very close to exact only after two iterations. Copyright © 2001 John Wiley & Sons, Ltd.
Seismic isolation of cable‐stayed bridges for near‐field ground motions
Authors: Wesolowsky Michael J. , Wilson John C. 
Published: January 2005

AbstractThis study examines the efficacy of using seismic isolation to favorably influence the seismic response of cable‐stayed bridges subjected to near‐field earthquake ground motions. In near‐field earthquake ground motions, large amplitude spectral accelerations can occur at long periods where many cable‐stayed bridges have significant structural response modes. This combination of factors can result in large tower accelerations and base shears. In this study, lead–rubber bearing seismic isolators were modeled for three cable‐stayed bridges, and three cases of isolation were examined for each bridge. The nine isolated bridge configurations, plus three non‐isolated configurations as references, were subjected to near‐field earthquake ground motions using three‐dimensional time‐history analyses. Introduction of a small amount of isolation is shown to be very beneficial in reducing seismic accelerations and forces while at the same time producing only a modest increase in the structural displacements. There is a low marginal benefit to continue to increase the amount of isolation by further lengthening the period of the structure because structural forces and accelerations reduce at a diminishing rate whereas structural displacements increase substantially. In virtually all cases the base shears in the isolated bridges were reduced by at least 50several instances by up to 80individual near‐field records showed large variability from one record to the next, with coefficients of variation about the mean as large as 50assessing the characteristics of near‐field ground motion for use in isolation design of cable‐stayed bridges. Copyright © 2003 John Wiley & Sons, Ltd.
Dynamic behavior of perimeter lateral‐system structures with flexible diaphragms
Authors: Fleischman R. B. , Farrow K. T. 
Published: January 2005

AbstractBuilding structures are typically designed using the assumption that the floor systems serve as a rigid diaphragm between the vertical elements of the lateral load‐resisting system. However, long‐floor span structures with perimeter lateral load‐resisting systems possess diaphragms which behave quite flexibly. The dynamic behaviour of such structures is dissimilar to the behavior expected of typical structures. This difference can lead to unexpected force and drift patterns. If force levels are sufficiently under‐estimated, inelastic diaphragm behaviour can occur, exacerbating the effects of diaphragm flexibility. Such response may lead to a non‐ductile diaphragm failure or structural instability due to high drift demands in the gravity system.Analytical models were developed which capture the diaphragm flexibility of structures with long‐floor spans and perimeter lateral‐systems. Modal examination and time‐history analyses were performed to determine the effect of diaphragm flexibility and diaphragm inelastic behaviour on the dynamic behaviour of these structures. Copyright © 2001 John Wiley & Sons, Ltd.
Seismic isolation of rigid cylindrical tanks using friction pendulum bearings
Authors: Wang Yen‐Po , Teng Min‐Cheng , Chung Kuo‐Whie 
Published: January 2005

AbstractStorage tanks are vulnerable to earthquakes, as numerous major earthquakes have demonstrated. The trend of recent revisions to make seismic design criteria for large‐scale industrial storage tanks increasingly stringent has made development of cost‐effective earthquake‐resistant design and retrofit techniques for industrial tanks imperative. This study assesses the feasibility of seismic base isolation for making liquid‐filled storage tanks earthquake resistant. The sliding‐type friction pendulum seismic (FPS) bearings are considered rather than the elastomeric bearings because the dynamic characteristics of an FPS‐isolated tank remain unchanged regardless of the storage level. This work has devised a hybrid structural‐hydrodynamic model and solution algorithm, which would permit simple, accurate and efficient assessment of the seismic response of rigid cylindrical storage tanks in the context of seismic isolation. Extensive numerical simulations confirm the effectiveness of seismic base isolation of rigid cylindrical tanks using FPS bearings. Copyright © 2001 John Wiley & Sons, Ltd.
Overview of the application of active/semiactive control to building structures in Japan
Authors: Nishitani Akira , Inoue Yutaka 
Published: January 2005

AbstractPerhaps one of the most significant technological innovations in the structural engineering field is the practical application of active and semiactive control to civil structures. A number of structures integrating active, hybrid, and semiactive response control technologies have been constructed in Japan. Most of them are building structures. This paper provides an overview of those building structures, focusing mainly on the types of buildings that are controlled, and on the types of control devices that are implemented. Future directions of structural engineering are also discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Active variable stiffness system with non‐resonant control
Authors: Nasu Tadashi , Kobori Takuji , Takahashi Motoichi , Niwa Naoki , Ogasawara Katsura 
Published: January 2005

AbstractThe active variable stiffness (AVS) system is proposed as a seismic response control system. It actively controls structural stiffness of a building to establish a non‐resonant state against earthquake excitations, thus suppressing the building's response. It consumes a relatively small amount of energy and maintains the safety of the building in moderate to severe earthquakes. In order to accumulate and analyse practical data, a building was constructed as a trial structure about ten years ago. This paper describes the control algorithm, the applied system, some observed earthquake records, verification of control effectiveness based on simulation analyses, and some issues concerning system maintenance. Through earthquake observations, it was confirmed that the system could select the appropriate stiffness that assures a non‐resonant state, which results in a minimum response. Copyright © 2001 John Wiley & Sons, Ltd.
A hybrid mass damper system controlled by H∞ control theory for reducing bending–torsion vibration of an actual building
Authors: Fujinami Takeyoshi , Saito Yoshihito , Morishita Masayuki , Koike Yuji , Tanida Koji 
Published: January 2005

AbstractA pair of hybrid mass dampers has been installed on an actual 23‐storey building located in Tokyo. The aim of the dampers is to counteract wind and smaller earthquake excited oscillations. H∞ control theory has been applied to control the dampers for reducing both bending and torsion vibrations simultaneously. For the design of the controller, identification parameters resulting from the forced vibration test of the building are adopted. The target of the controller performance is to reduce the vibration of first mode and to keep robust stabilization over the second or higher mode. From the results of forced vibration tests conducted after installation of the controller, it was confirmed that this system has proven control effect, largely satisfying what was aimed for in the design. Furthermore, system performance has been continually recorded during earthquakes, and analysis of the data has proved control effect. Copyright © 2001 John Wiley & Sons, Ltd.
Vibration control characteristics of a hybrid mass damper system installed in tall buildings
Authors: Saito Tomoo , Shiba Keiji , Tamura Kazuo 
Published: January 2005

AbstractA large‐scale hybrid mass damper (HMD) system was developed to reduce building response during strong winds and earthquakes of up to medium strength. The HMD consists of an auxiliary mass supported by multi‐stage rubber bearings and actuators driven by AC servomotors.Two HMDs were installed on the top floor of a target building to suppress both translational and torsional vibration. The system was installed in two high‐rise buildings. One was a 50‐storey, 200‐m high, steel‐frame building. The dynamic characteristics of both the building and the HMDs were identified through forced vibration tests using the HMD system. The effectiveness of the HMD system was confirmed by these tests and both wind and earthquake observation data.The other building was a triangular‐plan, 43‐storey, steel‐frame building. The dynamic characteristics of the building were estimated using two different methods. One method comprised a series of vibration tests using the HMDs to excite the building. The other method was an analysis of the earthquake response records of the building, which showed the additional damping effect of the HMD system. The performance of the HMD system during a strong typhoon was also analysed. Copyright © 2001 John Wiley & Sons, Ltd.
Practical applications of active mass dampers with hydraulic actuator
Authors: Yamamoto Masashi , Aizawa Satoru , Higashino Masahiko , Toyama Kotaro 
Published: January 2005

AbstractThe application of active mass damper (AMD) systems into buildings has been studied analytically and experimentally during the 1980s. The main purpose of these systems is to reduce the vibrations of buildings during strong winds or small earthquakes in order to improve the comfort of the building occupants. The authors have worked on the study and development of an AMD system using an electro‐servo‐type hydraulic actuator.First, the control technique of AMD with hydraulic actuator is formulated. Hydraulic actuators have an advantage of high durability and high cost performance, however, they also have non‐linear dynamics, which makes their control difficult.Second, the applications of this system in the buildings are shown. The authors have applied this AMD system to four buildings in Japan. The outlines of these AMDs and buildings are described individually. To verify the control performance of the AMD in these buildings, free vibration tests were carried out just before their completion. Free vibration test results of each building demonstrated good control performance. After the completion, wind and earthquake observations were conducted. The records have shown a good performance of energy absorption of the vibration during wind excitation and small level earthquakes. Copyright © 2001 John Wiley & Sons, Ltd.
Hybrid mass dampers using two types of electric servomotors: AC servomotors and linear‐induction servomotors
Authors: Nakamura Y. , Tanaka K. , Nakayama M. , Fujita T. 
Published: January 2005

AbstractA hybrid mass damper (HMD) using an electric servomotor for vibration control of buildings has been developed. The developed HMD has been installed in three buildings in order to improve habitability during strong winds and small‐to‐moderate earthquakes. We speculated that its high performance, compactness, and high reliability are important factors in its practical application to actual buildings. We have designed and installed the HMD system with suitable specifications for the size and demands of various object buildings. Several improvements were required for each application, e.g., the adoption of an active/passive‐mode switching mechanism and fault diagnosis method, countermeasures for scaling up of the device, a linear‐induction servomotor, and a design controller based on the H‐infinity control theory. In this paper, techniques relevant to vibration‐control system design, an outline of applied HMD, the design of the control system, and the verified results of control performance are presented. Through several vibration tests and field observations on each building during high winds and earthquakes, the efficiency of the applied HMD system was examined and verified. Copyright © 2001 John Wiley & Sons, Ltd.
Seismic interaction in linearly connected electrical substation equipment
Authors: Der Kiureghian A. , Sackman J. L. , Hong K‐J. 
Published: January 2005

AbstractAn electrical substation consists of a complex set of equipment items that are interconnected through conductor buses or cables. If the connections are not sufficiently flexible, significant dynamic interaction may occur between the connected equipment items during a seismic excitation. This interaction is believed to be responsible for some of the observed substation equipment damage in recent earthquakes. This paper investigates the interaction between two equipment items connected by a linear spring‐dashpot or spring‐dashpot‐mass element representing a conductor bus. It is found that the interaction between the two equipment items may significantly amplify the response of the higher‐frequency equipment item. The influences of various key parameters on the interaction effect are quantified. Means for reducing the adverse interaction effect are described. Copyright © 2001 John Wiley & Sons, Ltd.
The production of digital elevation models for experimental model landscapes
Authors: Hancock Greg , Willgoose Garry 
Published: January 2005

AbstractAutomated digital photogrammetry was used to produce digital elevation models of experimental model landscapes under controlled laboratory conditions as part of a series of rainfall erosion experiments looking at the evolution of landforms in response to erosion. The method allowed the elevations of the experimental landscapes to be studied in great detail on a regular grid digital terrain map with relatively very little effort. Digital photogrammetry produced elevation data at a resolution of 6 mm with a standard deviation of 2·0 mm over an experimental catchment relief of approximately 200 mm; this resolution is considerably better than that achievable by conventional manual photogrammetry. The density of grid points was sufficiently high that small‐scale details such as knickpoints developing in channels were represented. The method can facilitate the study of both experimental and natural landscapes in great detail. Copyright © 2001 John Wiley & Sons, Ltd.
Gully‐head erosion processes on a semi‐arid valley floor in Kenya: a case study into temporal variation and sediment budgeting
Authors: Oostwoud Wijdenes D. J. , Bryan R. 
Published: January 2005

AbstractA three year monitoring programme of gully‐head retreat was established to assess the significance of sediment production in a drainage network that expanded rapidly by gully‐head erosion on the low‐angled alluvio‐lacustrine Njemps Flats in semi‐arid Baringo District, Kenya. This paper discusses the factors controlling the large observed spatial and temporal variation in gully‐head retreat rates, ranging from 0 to 15 m a−1. The selected gullies differed in planform and in runoff‐contributing catchment area but soil material and land use were similar. The data were analysed at event and annual timescales. The results show that at annual timescale rainfall amount appears to be a good indicator of gully‐head retreat, while at storm‐event timescale rainfall distribution has to be taken into account. A model is proposed, including only rainfall (P) and the number of dry days (DD) between storms:

which explains 56 per cent of the variation in retreat rate of the single‐headed gully of Lam1.A detailed sediment budget has been established for Lam1 and its runoff‐contributing area (RCA). By measuring sediment input from the RCA, the sediment output by channelized flow and linear retreat of the gully head for nine storms, it can be seen that erosion shifts between different components of the budget depending on the duration of the dry period (DD) between storms. Sediment input from the RCA was usually the largest component for the smaller storms. The erosion of the gully head occurred as a direct effect of runoff falling over the edge (GHwaterfall) and of the indirect destabilization of the adjacent walls by the waterfall erosion and by saturation (GHmass/storage). The latter component (GHmass/storage) was usually much larger that the former (GHwaterfall). The sediment output from the gully was strongly related to the runoff volume while the linear retreat, because of its complex behaviour, was not.Overall, the results show that the annual retreat is the optimal timescale to predict retreat patterns. More detailed knowledge about relevant processes and interactions is necessary if gully‐head erosion is to be included in event‐based soil erosion models. Copyright © 2001 John Wiley & Sons, Ltd.