bluuebunny/crossref_metadata_2025 huggingface dataset:
The non‐stationary cross‐correlation coefficients in the seismic analysis of MDOF structural systems
Authors: Falsone Giovanni , Neri Fabio
Published: September 2003

A method concerning the evaluation, in a very compact form, of the non‐stationary modal cross‐correlation coefficients of MDOF structural systems subjected to seismic excitations is presented. It is available both in the case when the excitation is considered as a white‐noise process and when it is considered as a filtered process. The evaluation of these coefficients is required when a transient seismic analysis is performed by the use of the modal response spectrum approach. This is necessary when the strong‐motion phase of the earthquake is significantly short with respect to the fundamental period of the structure. Copyright © 2003 John Wiley & Sons, Ltd.
Predictive instantaneous optimal control of elastic structures during earthquakes
Authors: Wong Kevin K. F. , Yang Rong
Published: September 2003

A predictive instantaneous optimal control (PIOC) algorithm is proposed for controlling the seismic responses of elastic structures. This algorithm compensates for the time delay that happens in practical control applications by predicting the structural response over a period that equals the time delay, and by substituting the predicted response in the instantaneous optimal control (IOC) algorithm. The unique feature of this proposed PIOC algorithm is that it is simple and at the same time compensates for the time delay very effectively. Numerical examples of single degree of freedom structures are presented to compare the performance of PIOC and IOC systems for various time delay magnitudes. Results show that a time delay always causes degradation of control efficiency, but PIOC can greatly reduce this degradation compared to IOC. The effects of the structure's natural periods and the choice of control gains on the degradation induced by the time delay are also analyzed. Results show that shorter natural periods and larger control gains are both more sensitive and more serious to the degradation of control efficiency. Finally, a practical application of PIOC is performed on a six‐story moment‐resisting steel frame. It is demonstrated that PIOC contributes significantly to maintain stability in multiple degree of freedom structures, and at the same time PIOC has a satisfactory control performance. Copyright © 2003 John Wiley & Sons, Ltd.
Predictive instantaneous optimal control of inelastic structures during earthquakes
Authors: Wong Kevin K. F. , Yang Rong
Published: September 2003

A new inelastic structural control algorithm is proposed by incorporating the force analogy method (FAM) with the predictive instantaneous optimal control (PIOC) algorithm. While PIOC is very effective in compensating for the time delay for elastic structures, the FAM is highly efficient in performing the inelastic analysis. Unlike conventional inelastic analysis methods of changing stiffness, the FAM analyzes structures by varying the structural displacement field, and therefore the state transition matrix needs to be computed only once. This greatly simplifies the computation and makes inelastic analysis readily applicable to the PIOC algorithm. The proposed algorithm compensates for the time delay that happens in practical control systems by predicting the inelastic structural response over a period that equals the magnitude of the time delay. A one‐story frame with both strain‐hardening and strain‐softening inelastic characteristics is analyzed using this algorithm. Results show that the proposed control algorithm is feasibile for any inelastic structures. While the control efficiency deteriorates with the increase in magnitude of the time delay, the PIOC maintains acceptable performance within a wide range of time delay magnitudes. Finally, a computer model of a six‐story moment‐resisting steel frame is analyzed to show that PIOC has good control results for real inelastic structures. Copyright © 2003 John Wiley & Sons, Ltd.
Near‐fault spatial variation in strong ground motion due to rupture directivity and hanging wall effects from the Chi‐Chi, Taiwan earthquake
Authors: Shabestari Khosrow T. , Yamazaki Fumio
Published: September 2003

Damaging earthquakes feature large variations in the spatial ground motion distribution mainly due to source complexity, radiation pattern, and site conditions. In this study, we tried to capture the hanging wall and rupture directivity effects from the 1999 Chi‐Chi, Taiwan earthquake (Mw=7.6), which provides the largest acceleration data set since the strong‐motion seismology studies began. First, the event‐specific attenuation relations of strong‐motion parameters for the near‐field, hanging wall and footwall sites were developed. Then an empirical hanging wall model for peak ground acceleration (PGA) was introduced to get the residuals from the obtained attenuation relationships. The new empirical model for the PGA on the hanging wall indicates 46% to 50% higher values than the predicted means over the near‐field distance ranges. Finally, a period‐dependent empirical spectral amplitude factor model representing the directivity effects for the dip‐slip faulting system was developed using the Somerville et al. directivity model. The proposed model shows a larger spectral amplification factor than the result of the previous study. During the Chi‐Chi earthquake, the maximum spectral directivity factors have been registered in the up‐dip region, located around the surface exposure of the Chelungpu fault, in the range of 1.1 to 1.3 for the structural periods from 0.6s to 5.0s. Since the proposed spectral directivity factor was derived from the residual function of the single event without any influence of inter‐event variability, the model is magnitude‐ and distance‐independent. Hence the result can be easily implemented into attenuation relations, seismic hazard assessment, and building code revision studies for the regions with a dip‐slip faulting. Copyright 2003 © John Wiley & Sons, Ltd.
Response spectral attenuation relationships for Singapore and the Malay Peninsula due to distant Sumatran‐fault earthquakes
Authors: Megawati Kusnowidjaja , Pan Tso‐Chien , Koketsu Kazuki
Published: September 2003

As part of the effort to assess the seismic hazards of Singapore and the Malay Peninsula, representative ground motion prediction models have to be established. Seven existing attenuation relationships developed for shallow crustal earthquakes in stable continent and active tectonic regions are examined, and they are found to consistently over‐predict the ground motions of Sumatran‐fault earthquakes recently recorded in Singapore. This may be attributed to the differences in the regional crustal structures and distance ranges considered. Since the number of recorded ground motions in the region is very limited, a new set of attenuation relationships is derived based on synthetic seismograms. The uncertainties in rupture parameters, such as stress drop, focal depth, dip and rake angles, are defined according to the regional geological and tectonic settings as well as the ruptures of previous earthquakes. Ground motions are simulated for earthquakes with Mw ranging from 4.0 to 8.0, within a distance range from 174 to 1379km. Besides magnitude and distance, source‐to‐station azimuth is found to influence the amplitudes of the ground motions simulated. Thus, the azimuth is taken as an independent variable in the derived ground motion attenuation relationships. The Sumatran‐fault segments that have the potential to generate a specified level of response spectral accelerations in Singapore and Kuala Lumpur are identified based on the newly derived ground motion models. Copyright © 2003 John Wiley & Sons, Ltd.
Hydrology and water resources in monsoon Asia: a consideration of the necessity of establishing a standing research community of hydrology and water resources in the Asia Pacific region
Authors: Musiake Katumi
Published: September 2003

Hydrological and water resources issues appear very differently in different regions, and are strongly affected by geographical conditions. Hydrological knowledge and methodologies obtained in a specific region cannot necessarily be adapted to other regions. The purpose of this paper is to clarify one way to address adequately the regional characteristics of hydrology and water resources in monsoon Asia, especially the ‘too much water’ problems in the region. For this purpose, geomorphological factors, climatic factors and human intervention in the natural environment are taken into consideration as the three major factors governing the regional characteristics of the hydrology–water resources system. To identify geomorphological features macroscopically between the Asia Pacific region and other continental regions, the concepts ‘tectonic zone’ and ‘stable region’, which are two major subdivisions of continental masses in the world, are introduced. Also, a new climatic subdivision termed ‘warm‐humid’ is proposed to express the abundant precipitation due to the Asian monsoon. Then, hydrological characteristics common or similar in ‘warm‐humid tectonic zones’ in the Asia Pacific region, contrasted with those in stable regions, are enumerated together with the human intervention corresponding to these characteristics, and research targets peculiar to warm‐humid tectonic zones are discussed. Finally, the establishment of a standing research community called ‘Asia Pacific Association of Hydrology and Water Resources’ is proposed to promote the exchange of operational knowledge and experience in water resources management, cooperative research activities, and professional education in the Asia Pacific region. Copyright © 2003 John Wiley & Sons, Ltd.
Innovative resettlement schemes planned for the Numata Dam project
Authors: Nakayama Mikiyasu
Published: September 2003

The Numata Dam, planned for the Tone River basin of Gunma Prefecture, was the largest dam construction project ever considered in Japan. This dam construction project, however, did not materialize. The proposal for the Numata Dam was first launched in 1959, at a time when the Tokyo Metropolitan area was mushrooming, both in population and industrial activity. The Numata Dam was supposed to be a prioritized dam construction project to alleviate the then anticipated water shortage in the Tokyo Metropolitan area. The Numata Dam plan experienced fierce opposition from those who would have been obliged to resettle, whereas those in Tokyo and the surrounding metropolitan area welcomed the plan. The major concern of the planned Numata Dam was the number of resettlers, which was then estimated to be around 3000 families. The resettlement plan developed for the Numata Dam included some innovative concepts, which may be applicable even today, for dam construction projects in the developing world. The plan included such ideas as (a) having resettlers share existing farmland with the present owners provided improvements were made to increase productivity, (b) paying ‘rent’ to resettlers, and (c) establishing the Tone River Development Agency. After more than a decade of debate, both at national and local levels, the Numata Dam project was finally discarded through a decision of the Prime Minister in 1972. The resettlement schemes elaborated for the Numata Dam still appear to be innovative. Such schemes may be applied to projects in the developing world, in particular, in nations that are about to ‘take off’ with economic development. Copyright © 2003 John Wiley & Sons, Ltd.
Energy, water, plant interactions: ‘green feedback’ as a mechanism for environmental management and control through the application of phytotechnology and ecohydrology
Authors: Zalewski Maciej , Santiago‐Fandino Vicente , Neate John
Published: September 2003

One of the fundamental tenets of the sustainable development concept is the maintenance of a homeostatic equilibrium within the ecosystem. Overexploitation of the ecosystem or degradation of its biotic structure alters ecosystem processes to the point whereby the ability of the ecosystem to produce desired resources is seriously diminished. Water is the medium for all ecological processes, from molecular to global scale. The physical quantification of ecological processes in terms of energy and molecular dimension is fundamental for scientific investigation and sound ecosystem management. As a consequence, the water mesocycle within the basin and connected processes (i.e. those which can be measured) should be considered as the basic unit for the analysis of energy–water–biota interactions.

The degradation of freshwater ecosystems can be characterized in terms of two dimensions: first, pollution, which can be reduced to a significant extent by technologies; and second, the degradation of established water and nutrient cycles within the ecosystem as a whole. This second dimension is much more complex. A new approach for solving both of these problems is the application of ecohydrology and phytotechnology. Our progressive understanding of the range of anthropogenic degradation of hydrological, biogeochemical and biological processes within water basins indicates the need to control and regulate nutrients and water dynamics by increasing plant biomass and diversity. Thus, phytotechnologies, applied within the context of ecohydrological principles, can provide an approach for increasing ecosystem carrying capacity and enhancing the resilience and functionality of ecosystems at the basin scale.

The application of these interdisciplinary, holistic approaches, based on an understanding of the role of plant biomass in the control of water and biogeochemical cycles (i.e. ‘green feedback’), can lead to an improvement of water resources quality, as well as the enhancement of system biodiversity, agricultural production, and bioenergy generation, with the potential for increased employment opportunities. Copyright © 2003 John Wiley & Sons, Ltd.
Optimization of storage reservoir considering water quantity and quality
Authors: Chaves Paulo , Kojiri Toshiharu , Yamashiki Yosuke
Published: September 2003

Many factors influence water quality within a reservoir. Deforestation, excessive erosion, introduction of new species, domestic and industrial waste disposal and agricultural runoff are only a few examples.

It is well known by specialists in water resources management that water levels in a reservoir may also affect its quality. But how these processes occur and how appropriate water levels can be maintained are very hard questions to answer. This is because of the physical and biological processes occurring inside the water body, and also due to the various demands from society concerning water uses.

Nowadays, through the use of models, knowledge of some of the conditions can enable us to predict future conditions. In many cases, reservoir models, such as physical models for water quality, may predict the future water quality situation. These models have been used successfully to enhance knowledge about the interactions among the different parts inherent to the water systems.

Through the combination of water quality and optimization models, this study proposes a suitable methodology for the assessment of planning operations of a storage reservoir. The purpose of this paper is to consider a multipurpose reservoir, under different water demands and uses from societies, concerning reservoir water quality.

The proposed optimization is realized through the use of dynamic programming combined with stochastic techniques that can handle the probabilistic characteristics of inflow quantity and quality. For the water quality assessment, the UNEP/ILEC one‐dimensional model with two layers called PAMOLARE is applied. Finally, sensitivity analysis is carried out using a genetic algorithm model. Copyright © 2003 John Wiley & Sons, Ltd.
A continental scale hydrological model using the distributed approach and its application to Asia
Authors: Yang Dawen , Musiake Katsumi
Published: September 2003

Continental scale hydrological models are important for improving the land surface scheme of the General Circulation Model (GCM) and for downscaling applications of GCM predictions for regional water resources assessment. A grid‐based distributed hydrological modelling approach cannot be applied at a continental scale by simply increasing the grid size due to factors such as the spatial heterogeneity and nonlinear nature of soil–vegetation–atmosphere transfer processes. Sub‐grid parameterization is required to capture the spatial variability of hydrological behaviour within a large grid. On the other hand, water resources management is usually implemented at the basin scale. The methodology presented in this study expands a grid‐based distributed hydrological model to the continental scale, and addresses both sub‐grid hydrological parameterization and basin‐based water resources assessment. A continental scale model with a 0·5° spatial resolution is developed based on a number of available global data sets. The model performance is examined through application to the Asian Continent. The regional and temporal variability of hydrological characteristics and water resources is discussed in this paper. Copyright © 2003 John Wiley & Sons, Ltd.
Aircraft observations of the atmospheric boundary layer over a heterogeneous surface in eastern Siberia
Authors: Hiyama T. , Strunin M. A. , Suzuki R. , Asanuma J. , Mezrin M. Y. , Bezrukova N. A. , Ohata T.
Published: September 2003

This paper outlines specifications and gives preliminary results of aircraft observations made during the Intensive Observation Period in 2000 (IOP2000) over the Yakutsk area of eastern Siberia. The observations were part of the GAME‐Siberia project. Spatial and seasonal variation in the fluxes of sensible heat, latent heat, and carbon dioxide were determined using a Russian aircraft equipped with turbulence sensors. Two flight paths covered 12 × 32 km2 grids over heterogeneous forest and grass surfaces on the left‐ and right‐hand banks of the Lena River. The spatial flux distributions were consistent with the underlying vegetation cover. A video camera recorded aerial images of the land, while a spectrometer observed the spectral reflectance of the land surface. These data helped describe the relationship between the atmosphere and the land surface. The vertical structure of the atmospheric boundary layer (ABL) was also observed on long flight paths between the left and right banks of the Lena River. Thermally induced internal boundary layers (TIBLs) developed in the ABL under different thermal and dynamic conditions near the Lena River. The horizontal and vertical distributions of sensible and latent heats in the ABL were consistent with the generation of cumulus, which appeared over the forested area, but not over the Lena River lowland. Copyright © 2003 John Wiley & Sons, Ltd.
Hydrological regime analysis of the Selenge River basin, Mongolia
Authors: Ma X. , Yasunari T. , Ohata T. , Natsagdorj L. , Davaa G. , Oyunbaatar D.
Published: September 2003

Arid and semi‐arid regions are very vulnerable to environmental changes. Climate change studies indicate that the environment in such areas will steadily deteriorate with global warming; inland lakes will shrink and desert areas will expand. Mongolia is a landlocked country in north‐central Asia that contains a unique ecological system consisting of taiga, steppe, and desert from north to south. The Selenge River basin (280 000 km2) in northern Mongolia is a semi‐arid region underlain by permafrost, between latitudes 46 and 52°N, and longitudes 96 and 109°E. The issue of sustainable development of the basin is very important owing to its limited natural resources, including fresh water, forest, and rangeland. To examine the water cycle processes in the basin, a hydrological analysis was carried out using a simple scheme for the interaction between the land surface and atmosphere (big‐leaf model) coupled to a hydrological model for the period 1988–92 to estimate the hydrological regime of the basin. Annual precipitation in this period averaged 298 mm, ranging from 212 to 352 mm at a 1 ° × 1 ° resolution based on data from 10 gauges, and the estimated annual evapotranspiration averaged 241 mm, ranging between 153 and 300 mm. This indicates that evapotranspiration accounts for the overwhelming majority of the annual precipitation, averaging 81% and ranging between 64 and 96%. The annual potential evapotranspiration in the basin averaged 2009 mm; the ratio of evapotranspiration (actual to potential evapotranspiration) was 0·12 and the wetness index (annual precipitation to potential evapotranspiration) was 0·15. Copyright © 2003 John Wiley & Sons, Ltd.
Composite surgical sutures with bioactive glass coating
Authors: Boccaccini Aldo R. , Stamboulis Artemis G. , Rashid Azrina , Roether Judith A.
Published: September 2003

A processing method was developed to coat polyglactin 910 (Vicryl®) sutures with bioactive glass powder (45S5 Bioglass®). High reproducibility and homogeneity of the coating in terms of microstructure and thickness along the suture length were achieved. Bioglass®‐coated sutures exhibited a high level of chemical reactivity in simulated body fluid (SBF), indicating their bioactive behavior. This was evident by the prompt formation of hydroxyapatite (HA) crystals on the surface after only 7 days of immersion in SBF. These crystals grew to form a thick HA layer (15 μm thickness) after 3 weeks in SBF. The tensile strength of the sutures was tested before and after immersion in SBF in order to assess the effect of the bioactive glass coating on suture degradation. The tensile strength of composite sutures was lower than that of as‐received Vicryl® sutures, 385 and 467 MPa, respectively. However, after 28 days of immersion in SBF the residual tensile strengths of coated and uncoated sutures were similar (83 and 88 MPa, respectively), indicating no negative effect of the HA layer formation on the suture strength. The effect of bioactive glass coating on the polymer degradation is discussed. The developed bioactive sutures represent interesting materials for applications in wound healing, fabrication of fibrous three‐dimensional scaffolds for tissue engineering, and reinforcement elements for calcium‐phosphate temporary implants. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 67B: 618–626, 2003
Clinical and simulator wear study of alumina ceramic THR to 17 years and beyond
Authors: Shishido T. , Clarke I. C. , Williams P. , Boehler M. , Asano T. , Shoji H. , Masaoka T. , Yamamoto K. , Imakiire A.
Published: September 2003

Three THAs with cementless monolithic alumina ceramic sockets and cementless Co‐alloy stems were retrieved because of aseptic loosening after 17 and 24 years. At revision heads and cups were marked for orientation. Maps were drawn of wear patterns with the use of light microscopy and surveyed by SEM. In a simulator experiment 28‐mm‐diameter alumina heads and liners were used. The cups were mounted inverted in a hip simulator and run with calf serum as the lubricant. The hip loads were 2 kN maximum and a 1‐Hz frequency for 20 million cycles. Wear severity was classified into five grades. In retrieved implants, SEM analysis showed that the main wear zones (MWZ) had Grade 4 wear. The peripheral wear zones (PWZ) showed grain pull‐out regions (Grade 5 wear). These corresponded to neck‐socket impingement and head‐acetabular cup separation. Gray was due to transferred CoCr particles from the stem. In the simulator study, the MWZ had only localized areas of grain pull out surrounded by polished surface regions (Grade 4 wear) at 20 million cycles; stripe wear was not seen. The alumina ceramic bearings proved excellent up to 22 years in simulator studies and clinical studies. However, microseparation kinematics would be necessary in the simulator to duplicate the more peripheral wear zones. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 67B: 638–647, 2003
Paraffin spheres as porogen to fabricate poly(L‐lactic acid) scaffolds with improved cytocompatibility for cartilage tissue engineering
Authors: Ma Zuwei , Gao Changyou , Gong Yihong , Shen Jiacong
Published: September 2003

Three‐dimensional poly(L‐lactic acid) (PLLA) scaffolds with high porosity and pore size ranging from 150 to 700 μm were conveniently prepared with paraffin spheres used as porogen. PLLA/1,4‐dioxane solution containing a given amount of paraffin spheres was frozen at −25 °C to obtain a solidified mixture, followed with freeze drying and subsequent leaching with hexane to remove the 1,4‐dioxane and paraffin spheres, respectively. The fabricated PLLA scaffolds were highly porous with evenly distributed and interconnected pores. The microstructures of the PLLA scaffolds as a function of paraffin‐sphere size, paraffin‐sphere dosage, and PLLA concentration were characterized by confocal laser scanning microscopy (CLSM) and scanning‐electronic microscopy (SEM). To improve the cytocompatibility of the bioinert material, a hybrid PLLA scaffold containing Type I collagen was prepared by pressing the collagen solution into the scaffold under reduced pressure. The amounts of the collagen introduced in the scaffolds were detected by ninhydrin method. The distribution of the collagen in the scaffolds was studied with CLSM. Finally, in vitro cell culture was performed by injecting a chondrocyte suspension into the scaffolds. The results showed that the chondrocytes were more evenly distributed and more spread out in the collagen‐modified PLLA scaffolds than in the unmodified ones. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 67B: 610–617, 2003
An animal evaluation of a paste of chitosan glutamate and hydroxyapatite as a synthetic bone graft material
Authors: Mukherjee D. P. , Tunkle A. S. , Roberts R. A. , Clavenna A. , Rogers S. , Smith D.
Published: September 2003

The objective of this study was to develop a synthetic bone graft in a paste form. Reported here are the results of the evaluation of a paste of chitosan glutamate (Protosan®) and hydroxyapatite (referred to as a paste) used in a critical size defect model in rats. Eight–millimeter—diameter cranial defects were made in rat calvaria following a protocol approved by the animal review committee. Five groups were studied: (1) empty control, (2) defect filled with paste only, (3) defect filled with the paste containing bone‐marrow aspirate, (4) defect filled with paste containing BMP‐2, and (5) defect filled with paste containing osteoblasts cultured from bone‐marrow aspirate. The sacrifice intervals were 9 and 18 weeks. Calvaria containing the defect were harvested, and the bone mineral density (BMD) was determined by dual energy X‐ray absorptiometry. Push‐out strength measurements were also performed. The BMD values of empty control were significantly lower than those of other groups at both 9 and 18 weeks. The mechanical properties, that is, push‐out strengths and area under the push‐out load and displacement were not significantly different between the samples. Histological examination of Goldner‐trichromestained undecalcified sections showed the presence of mineralized bone spicules in the defect areas that were more prominent in those filled with paste and osteoblasts cultured from bone‐marrow aspirate. Hence, this study demonstrated that the paste of chitosan glutamate and hydroxyapatite‐containing osteoblasts cultured from bone‐marrow aspirate would be an effective material to repair bone defects. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 67B: 603–609, 2003
A new model of implant‐related osteomyelitis in rats
Authors: Lucke M. , Schmidmaier G. , Sadoni S. , Wildemann B. , Schiller R. , Stemberger A. , Haas N.P. , Raschke M.
Published: September 2003

Infection related to osteosynthesis often has dramatic consequences for the patient. Prolonged hospitalization with systemic antibiotic therapy, several revision procedures, possible amputation, and even death may occur. To investigate the pathology of infection in orthopedic surgery, a new rat model of implant related osteomyelitis was developed. Three different concentrations (106, 103, and 102 colony‐forming units (CFU)/10 μl) of Staphylococcus aureus were inoculated into the tibial medullary cavity with simultaneous insertion of a titanium Kirschner wire. Controls received phosphate‐buffered saline (PBS). Each group consisted of 10 animals. Animals were followed for 4 weeks until sacrifice. X‐rays of the tibiae were taken weekly, blood counts were analyzed, and body temperature and weight were determined. After sacrifice, infection was evaluated by histological and microbiological investigations. All animals inoculated with Staph. aureus in either concentration developed microbiological, histological, and radiological signs of osteomyelitis in correlation to the amount of inoculated bacteria. X‐rays clearly revealed osseous destruction after 14 days with progression of osteomyelitis during the following weeks. CFU/g bone and bone weight after sacrifice showed dependence on the amount of inoculated CFU. The histological results confirmed the radiological findings. No significant changes in blood counts, body weight, and body temperature between the groups could be observed. The results demonstrate that it is possible to develop a model of implant‐related osteomyelitis in rats with dependence on the amount of inoculated bacteria. No other promoters of infection besides intramedullary insertion of titanium Kirschner wires were used in this model. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 67B: 593–602, 2003
Phase evolution during the formation of stoichiometric hydroxyapatite at 37.4 °C
Authors: Greish Yaser E. , Brown Paul W.
Published: September 2003

The mechanism of formation of stoichiometric hydroxyapatite in aqueous solution by the acid–base reaction of the precursor calcium phosphates tetracalcium phosphate [Ca4(PO4)2O, TetCP] and anhydrous dicalcium phosphate (CaHPO4, DCPA) was investigated. Phase evolution during the formation of hydroxyapatite was studied, and could be correlated with the kinetics of reaction. Initial dissolution of precursors is followed by hydroxyapatite nucleation and growth. Consumption of DCPA precedes that of TetCP and results in the formation of nonstoichiometric hydroxyapatite. As a result of continued TetCP dissolution, the pH of the solution increases towards a pH at which hydroxyapatite and Ca(OH)2 co‐exist in equilibrium. Hydroxyapatite formation takes place in two stages: initially formed, nonstoichiometric hydroxyapatite subsequently reacts with TetCP and is converted to stoichiometric hydroxyapatite. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 67B: 632–637, 2003
Polydimethylsiloxane versus polytetrafluoroethylene for vocal fold medialization: Histologic evaluation in a rabbit model
Authors: Caballero Miguel , Bernal‐Sprekelsen Manuel , Calvo Carlos , Farrè Xavier , Quintó Lorenc , Alòs Lucia
Published: September 2003

The objective is to study the tissue reaction of the paralyzed vocal cord in response to the injection of particulate plastics in a rabbit model. Forty‐five New Zealand rabbits with surgical vocal‐fold paralysis were used in the study. Histologic reactions of the larynx and the regional lymph nodes were analyzed by a single blinded pathologist at 6 weeks and 6 months after a vocal‐cord injection of Teflon or of silicone elastomer. Macroscopic studies of the liver, lungs, spleen, kidney, and brain were performed. The histological study showed a greater proportion of chronic granulomatous inflammation in animals injected with silicone than in those injected with Teflon. The immunohistochemical study showed a higher degree of phagocytosis of Teflon particles than of the silicone particles. The silicone group presented a more severe fibrous reaction than the Teflon group, but the difference was not significant. No migration particles were found. It is concluded that silicone, having a greater viscosity than Teflon because of the size of its particles, induces more fibrosis and a larger proportion of foreign giant cells in the host. Due to this histological reaction, silicone particles present greater anchorage and stability. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 67B: 666–674, 2003
Host protection against deliberate bacterial contamination of an extracellular matrix bioscaffold versus Dacron™ mesh in a dog model of orthopedic soft tissue repair
Authors: Badylak Stephen F. , Ching Wu Ching , Bible Melissa , McPherson Edward
Published: September 2003

The resistance of two biomaterials, one synthetic and one biologic in origin, to deliberate bacterial infection was compared in a dog model of orthopedic soft tissue reconstruction. Twenty‐four adult female dogs were randomly divided into two equal groups and a 2.0‐cm‐round full‐thickness defect was created on the lateral surface of the stifle joint, leaving only the synovium and skin intact. The defect was surgically repaired with either Dacron™ mesh or a porcine derived extracellular matrix (ECM) scaffold material. The repair site was inoculated with 1 × 108 Staphylococcus aureus at the time of surgery and the dogs were survived for 28 days. Results showed a chronic pyogranulomatous inflammatory response at the Dacron™ implant sites versus a constructive tissue‐remodeling response without residual inflammation at the ECM implant site. Three dogs in the group receiving the Dacron™ mesh were treated with Keflex™ (500 mg bid × 7 days) for signs of septicemia. A quantitative bacterial count of the implant sites at the time of sacrifice showed 6.52 × 105 ± 1.2 × 106 and 6.5 × 102 ± 1.8 × 103 bacteria per gram of tissue for the Dacron™ and ECM scaffold sites, respectively (P < .03). The ECM implant material was more resistant than the synthetic implant material to persistent infection following deliberate bacterial contamination and the ECM scaffold supported constructive tissue remodeling. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 67B: 648–654, 2003
Temperature elevation after vertebroplasty with polymethyl‐methacrylate in the goat spine
Authors: Verlaan Jorrit‐Jan , Oner F. Cumhur , Verbout Abraham J. , Dhert Wouter J. A.
Published: September 2003

Although the general complication rate for vertebroplasty is low, neural compression and thermal damage have been related to the use of polymethyl‐methacrylate cement. This study focuses on the risk of thermal tissue damage after vertebroplasty. In this study, cavities were created by a transpedicular approach in the vertebral bodies (L3, L4, and L5) of four milk goats, and polymethyl‐methacrylate cement was injected. In three locations (the bone–cement interface, the epidural space, and the disc space) the temperature was measured in regular intervals after injection of the cement. The mean injected volume was 0.8 ml, which accounted for a 22% volume fraction. The mean peak temperature of the bone–cement interface was 44.6 °C, while the maximum temperature at the epidural space and disc space was 37.0 and 37.5 °C, respectively. The local temperature measured afterin vivovertebroplasty did not reach values that are known to cause tissue necrosis. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 67B: 581–585, 2003
Cavernous hemangioma of the breast: Mammographic and sonographic findings and follow‐up in a patient receiving hormone‐replacement therapy
Authors: Mesurolle Benoît , Wexler Marvin , Halwani Fawaz , Aldis Ann , Veksler Anna , Kao Ellen
Published: September 2003

We report the case of a 78‐year‐old woman who had been receiving hormone‐replacement therapy (HRT) for 6 years and had a 4‐month history of a painless nodule in the 9 o'clock position in her right breast. Mammography performed 4 years previously had shown a 4‐mm bilobed, ovoid, well‐defined nodule in that location; mammography performed 1 year previously had shown that the nodule had increased to 6 mm. We performed mammographic and sonographic examinations, which revealed a 10‐mm ovoid nodule in the same 9 o'clock position in the right breast. The imaging findings appeared to indicate benignity, but because of the increasing size of the nodule, we undertook an ultrasound‐guided large‐core needle biopsy. The histopathologic diagnosis was typical cavernous hemangioma. It was not excised, but HRT was discontinued. Follow‐up mammography and sonography 8 months later showed that the nodule had decreased to 6 mm. We believe that the HRT played a contributory role in the increasing size of this patient's cavernous hemangioma. The use of ultrasound‐guided large‐core needle biopsy is reliable enough to ascertain the benignity of such masses and can thus avoid, if it is clinically appropriate, the need for their surgical removal. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:430–436, 2003
Mirror‐image artifact mimicking epidural hematoma: Usefulness of power doppler sonography
Authors: Cakmakci Handan , Gulcu Aytac , Zenger M. Noyan
Published: September 2003

During sonographic examination, a mirror‐like interface can scatter the ultrasound beam, producing mirror‐image artifacts. We describe a case of bilateral parietal cephalhematoma in the parietal region of a 2‐day‐old neonate that mimicked bilateral epidural hematoma on routine sonographic examination. Forceps had been used during delivery, and the neonate had been experiencing episodes of apnea since birth. Gray‐scale coronal sonograms showed anechoic structures resembling epidural hematomas in the left and right parietal regions. However, color and power Doppler sonography showed normal vascular findings, thus permitting identification of the mirror‐image artifact. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:437–439, 2003
Sonographic evaluation of the anterior liver surface in chronic liver diseases using a 7.5‐MHz annular‐array transducer: Correlation with laparoscopic and histopathologic findings
Authors: Nagata Naruhiko , Miyachi Hayato , Nakano Atsushi , Nanri Kazuhide , Kobayashi Hisao , Matsuzaki Shohei
Published: September 2003

Purpose

We studied the sonographic appearance of the anterior liver surface using an ultrasound scanner equipped with a 7.5‐MHz annular‐array transducer to determine the accuracy of this imaging modality in monitoring the course of chronic liver diseases.

Methods

We prospectively evaluated patterns of the liver surface in the sonograms of 77 consecutive patients with chronic liver diseases who had undergone sonographic examination with a 7.5‐MHz annular‐array transducer and a 3.75‐MHz convex‐array transducer over a 2‐year period and compared these findings with those of laparoscopy (using previously described categories) and histopathology.

Results

Histopathologically confirmed disease prevalences for inactive chronic hepatitis, active chronic hepatitis, liver cirrhosis, and others were 10% (8/77), 56% (43/77), 29% (22/77), and 5% (4/77), respectively. The sonographic appearance of the liver surface with the 3.75‐MHz transducer was classified as either a regular or an irregular pattern. The regular pattern corresponded to 69% (34/50) of the cases in laparoscopic category 200 or 300 and the irregular pattern with 85% (23/27) of the cases in category 400 or 500. The sonographic appearance of the liver surface with the 7.5‐MHz transducer was classified as regular, unevenly irregular, diffusely irregular, or nodular. These 4 patterns detected 75% (24/32), 78% (14/18), 52% (12/23), and 75% (3/4) of the cases of laparoscopic categories 200, 300, 400, and 500, respectively. In a comparison of the sonographic patterns of the liver surface with the differential histopathologic findings, the regular sonographic pattern corresponded to 88% (7/8) of the cases of inactive chronic hepatitis, the unevenly irregular pattern with 35% (15/43) of the cases of active chronic hepatitis, and the diffusely irregular and nodular patterns (considered as 1 group) with 68% (15/22) of the cases of liver cirrhosis.

Conclusions

Our results suggest that sonographic evaluation of the liver surface with a 7.5‐MHz annular‐array transducer using this classification provides detailed information on the evolution of chronic liver diseases that correlates with the laparoscopic and histopathologic findings and thus is a useful noninvasive method for monitoring the disease course to cirrhosis. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31: 393–400, 2003
Diagnosis of arterial occlusive disease of the upper extremities: Comparison of color duplex sonography and angiography
Authors: Tola Muharrem , Yurdakul Mehmet , Ökten Sarper , Özdemir Ensar , Cumhur Turhan
Published: September 2003

Purpose

The aim of this study was to assess the abilities of color duplex sonography (CDUS) to detect and characterize arterial occlusive disease of the upper extremities.

Methods

We prospectively compared the results of CDUS with those of intra‐arterial digital subtraction angiography, which were considered definitive, in patients with symptomatic arterial occlusive disease of the upper extremities. In each extremity, we visualized 9 arterial segments, which were each evaluated for stenoses and occlusions. Each segment was categorized on each imaging modality as not significantly narrowed (narrowed by <50%), significantly narrowed (narrowed by ≥50% but <100%), or occluded (100%).

Results

We examined a total of 578 segments in 57 patients (34 men and 23 women) with a mean age of 50 years (range, 20–74 years). CDUS had a sensitivity, a specificity, a positive predictive value, a negative predictive value, and an accuracy of 98%, 99%, 97%, 99.5%, and 99%, respectively, for detecting occluded lesions and 79%, 100%, 100%, 99%, and 99%, respectively, for detecting hemodynamically significantly stenotic lesions. Notably, the sensitivity of CDUS for diagnosing significantly stenotic lesions (79%) was lower than that for diagnosing occlusive disease (98%).

Conclusions

With high sensitivity and accuracy rates, CDUS is a reliable screening method for detecting arterial occlusive disease of the upper extremities. This modality efficiently provides anatomic and hemodynamic data that are useful in cases of such disease. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:407–411, 2003
Transvaginal sonographic appearance of thrombosed uterine arteries after uterine artery embolization: the “White Snake” sign
Authors: Ahmad Iftikhar , Ray Charles E. , Conyers Carolyn
Published: September 2003

Purpose

The aim of this prospective study was to describe the appearance of thrombosed uterine arteries on transvaginal sonography performed after uterine artery embolization (UAE) and to assess the prognostic value of the “white snake” sign with regard to symptomatic outcome at 12 months.

Methods

Patients who underwent UAE from January 1, 1999, to July 31, 2000, for the treatment of symptomatic leiomyomas were included in the study. Transvaginal sonography was performed before and at 3, 6, and 12 months after UAE. Patients graded the severity of their symptoms on a scale from 1 to 5, with 1 being the least and 5 the most severe, before and at 12 months after the procedure. The Wilcoxon rank‐sum test was used to determine correlations between severity of symptoms and presence of the white snake sign; a p value of less than 0.05 was considered significant.

Results

During the study period, UAE was performed in 19 patients with a mean age of 41 years (range, 32–48 years). UAE was technically successful in all patients. Eighteen patients (95%) reported symptomatic improvement at 12 months: 8 patients (42%) by 4 severity‐scale points, 5(26%) by 3 points, and 5 (26%) by 2 points. The 1 patient who did not experience improvement had undergone a hysterectomy at 4 months after the UAE. At the 3‐month follow‐up, transvaginal sonography demonstrated a tortuous echogenic structure in the adnexa (the white snake sign) in all patients; the finding was still apparent in 10 patients at 6 months but in only 2 patients at 12 months. A direct correlation was found between persistence of the white snake sign and the degree of symptomatic improvement at 6 months (p = 0.04) but not at 12 months (p = 0.08).

Conclusions

After UAE, a thrombosed uterine artery appears on transvaginal sonography as an echogenic tortuous structure in the adnexa. Persistence of this white snake sign at 6 months after UAE may suggest a more favorable symptomatic outcome. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:401–406, 2003
Echogenic fetal lung masses: Comparison of prenatal sonographic and postnatal CT findings
Authors: Lee Hak Jong , Song Mi Jin , Cho Jeong Yeon , Lee Young‐Ho
Published: September 2003

Purpose

The aim of this retrospective study was to compare changes in size and appearance of fetal lung masses detected on prenatal sonography with those on postnatal CT.

Patients and Methods

Sixteen fetuses with echogenic lung masses had undergone serial sonography in utero as well as postnatal CT scanning. Changes in size of the masses were determined by comparing initial and follow‐up sonograms. The appearance of the lesions on postnatal CT scans was classified as consolidation, cavity, ground‐glass opacity, or atelectasis. All sonographic and CT findings were analyzed by 2 experienced radiologists who were unaware of previous imaging results.

Results

The initial mean size of the fetal lung masses on prenatal sonography was 31 (anteroposterior dimension) × 25 (width) × 36 (craniocaudal length) mm. Follow‐up serial sonography revealed complete regression of 10 masses, no change in 4, partial regression of 1, and increased size in 1. On postnatal chest CT, the mean mass size was 32 × 22 × 28 mm; 6 lesions showed no size change from that on the initial sonograms, 6 showed partial regression, and 4 showed an increase in size. Of the 10 cases with apparently complete regression on prenatal sonography, all showed positive findings on postnatal CT.

Conclusions

The discrepancy between prenatal sonographic and postnatal CT findings supports the assumption that regression of lung masses during serial prenatal sonographic follow‐up does not always indicate their complete regression. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:419–424, 2003
Gas‐phase ion thermochemistry in organometallic systems
Authors: Operti Lorenza , Rabezzana Roberto
Published: September 2003

I.
Introduction
408

II.
Techniques Employed to Measure Binding Energies
409

A.  Continuous‐Ejection Technique (CE)
409

B.  Equilibrium Measurements
409

C.  Kinetic Method
410

D.  Radiative Association (RA) Kinetics Method
410

E.  Threshold‐CID Experiments
410

F.  Zero‐Pressure Thermal Radiation‐Induced Dissociation Technique (ZTRID)
411

III.
Metal Ion—Ligand Binding Energies
411

A.  Lithium
411

B.  Sodium
412

C.  Magnesium
413

D.  Aluminum
414

E.  Silicon
414

F.  Potassium
414

G.  Calcium, Strontium
415

H.  Scandium
415

I.  Titanium
415

J.  Vanadium
415

K.  Chromium
416

L.  Manganese
416

M.  Iron
416

N.  Cobalt, Nickel
419

O.  Copper
419

P.  Zinc
421

Q.  Rubidium, Cesium
421

R.  Molibdenum, Tungsten
423

S.  Silver, Cadmium
423

T.  Platinum
425

References

425

This review represents a general overview on the determination of bond energies in gas‐phase organometallic systems. The paper focuses on articles published in the last 7 years, whose main scope was to experimentally measure metal ion–ligand binding energies. Therefore, studies of reactivity and characterization of ion complexes are not included, even if some of them display bond energies among the data measured. Bond energies are presented according to the metal ion complexed, in increasing order of atomic number. Periodic trends of binding energies and correlations among the various ligand are discussed. A brief summary of the most used techniques specifically devoted to gather bond energies is also provided. © 2003 Wiley Periodicals, Inc., Mass Spec Rev 22:407–428, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mas.10065