bluuebunny/crossref_metadata_2025 huggingface dataset:
Refined Plastic Hinge Analysis of Steel Frame Structures Comprising Non-Compact Sections II: Verification
Authors: Avery P. , Mahendran M.
Published: October 2002

Application of “advanced analysis” methods suitable for non-linear analysis and design of steel frame structures permits direct and accurate determination of ultimate system strengths, without resort to simplified elastic methods of analysis and semi-empirical specification equations. However, the application of advanced analysis methods has previously been restricted to steel frames comprising only compact sections that are not influenced by the effects of local buckling. A refined plastic hinge method suitable for practical advanced analysis of steel frame structures comprising non-compact sections is presented in a companion paper. The method implicitly accounts for the effects of gradual cross-sectional yielding, longitudinal spread of plasticity, initial geometric imperfections, residual stresses, and local buckling. The accuracy and precision of the method for the analysis of steel frames comprising non-compact sections is established in this paper by comparison with a comprehensive range of analytical benchmark frame solutions. The refined plastic hinge method is shown to be more accurate and precise than the conventional individual member design methods based on elastic analysis and specification equations.
Configurations of Single-Layer Barrel Vaults
Authors: El-Sheikh Ahmed
Published: October 2002

Single-layer barrel vaults with one radius of curvature may be fabricated with several common grid configurations. With different configurations, the vault' s performance and aesthetics vary considerably affecting both its competitiveness and suitability for different applications. The study presented in this paper is an assessment of the most commonly adopted vault configurations and their effect on the vault stiffness/weight value, member stress distribution, number, length and weight of members, degree of statical redundancy, resistance to failure mechanisms, reliance on joint rigidity and cost. The study is parametric and covers wide variations of the vault aspect ratio, span/rise ratio and boundary conditions. The results of this study should be of significant value to the design of future barrel vault structures.
Application of High-Performance Concrete to High-Rise Building in Taiwan
Authors: Chang Ping-Kun , Hwang Chao-Lung , Peng Yaw-Nan
Published: October 2002

The research and development of high-performance concrete (HPC) that can give both high flow characteristics and high strength have attracted wide interest in Taiwan. The construction of the 101-storey Taipei Financial Center and the 85-storey Tungtxt & Chingtai (T&C) Tower requires the slump to be in the range of 230 – 270 mm, the initial slump flow in the range of 580 – 620 mm and slump more than 230 mm after 45 minutes, as well as a 56-day compressive strength of over 56 MPa. The HPC mix is designed using a densified mixture design algorithm which aims to achieve the lowest cement content. With the addition of pozzolanic materials such as fly ash, the workability is much improved because the shape of fly ash is spherical. After one-year of strict quality control, the HPC achieve consistent workability and excellent strength. This indicates that the appropriate use of local industrial by-product materials can produce HPC of the required design strength.
Nondestructive Damage Detection of Bridges: A Status Review
Authors: Wang Xiaotong , Chang Chih-Chen , Fan Lichu
Published: October 2002

The recent advances in detecting and locating damage in bridges by different kinds of non-destructive testing and evaluation (NDT&E) methods are reviewed. From the application point of view, classifications for general bridge components and their damage types are presented. The relationships between damage, bridge components, and NDT&E techniques are summarized. Many useful WEB sources of NDT&E techniques in bridge damage detection are given. It is concluded that: (1) vibration-based damage detection methods are successful to a certain extent, especially when the overall damage is significant and, low frequency vibration can identify those areas where more detailed local inspection should be concentrated; (2) robust identification techniques that are able to locate damage based on realistic measured data sets still seem a long way from reality, and, basic research is still necessary in the mean time; (3) the rapid development of computer technology and digital signal processing (DSP) techniques greatly impacts upon the conventional NDT techniques, especially in control data processing and data displaying, as well as in simulation and modeling; (4) most of the NDT&E techniques introduced in this paper have their own practical commercial systems, but the effort required for combining the theoretical, experimental and engineering achievements, is still a challenging task when establishing the relationship between the unknown quantities and the measured signal parameters and specialised instruments have shown great advantages for doing some things more effectively than general ones; (5) in bridge damage detection, a problem usually requires the application of different NDT&E techniques; two or more independent techniques are needed to enable confidence in the results.
Uncoupling of Governing Equations for Cyclic Bi-Periodic Structures
Authors: Gao L. , Liu J. K.
Published: October 2002

The U-transformation method, a new analytical method, is very powerful in the static and dynamic analyses of structures with cyclic periodic properties. using the U-transformation method on a cyclic periodic structure is equivalent to projecting the orthogonal mode subspace displacement vector into the unitary space. The advantage of the U-transformation method is to make it possible to uncouple linear simultaneous equations, either algebraic or differential equations, which have cyclic bi-periodic properties. This paper provides a rigorous proof of this significant statement and gives the form of the uncoupled equations. The uncoupling principle for the governing equations for structures with cyclic bi-periodicity, is demonstrated not only in one direction but also in two directions. The result can be easily used in a procedure to obtain the solutions for static and dynamic analyses of bi-periodic structures.
Development of Ductility Design Guidelines for RC Beams with FRP Reinforcing Bars
Authors: Oehlers D. J. , Bui H. D. , Russell N. C. , Smyth G. J. , Waters D. R.
Published: October 2002

As corrosion is a common problem in steel reinforced concrete (RC), fibre reinforced plastic (FRP) reinforcement, that is corrosion resistant, has gained the attention of structural engineers. When overloaded, structural components must behave in a ductile fashion to provide adequate warning of imminent failure but due to the brittle nature of FRP materials, it has been difficult to incorporate ductility into FRP RC beams. However, previous research has revealed that placing FRP reinforcement in both the compression and the tensile zones of a beam section can result in a ductile failure mechanism, as the compressive FRP affects the ductile plateau of the moment-curvature sectional response. This paper quantifies minimum ductility requirements for the redistribution of bending moment in continuous FRP RC beams. Validation of ductility models by experimental testing allowed for the development of design rules to ensure that a beam incorporating FRP reinforcement will behave in a ductile fashion.
Numerical Analysis of Continuous Composite Beams under Service Loading
Authors: Bradford M. A. , Manh H. Vu , Gilbert R. I.
Published: October 2002

This paper presents a method for the service-load analysis of continuous composite beams. Both short-term and time-dependent analyses are carried out, in which cracking, creep and shrinkage of the concrete slab are considered. The time-dependent response of individual cross-sections is modelled using the Age-Adjusted Effective Modulus Method coupled with a relaxation procedure, and the lengthwise or longitudinal analysis of the member makes use of the force method of structural analysis. Both propped and unpropped construction may be modelled. The numerical solution requires iteration, but is suited to straightforward spreadsheet or conventional programming on a personal computer, on which the analysis is performed rapidly. The scope of the method is demonstrated in a simple example of the behaviour of a two-span beam with the same sustained loading that is cast propped or unpropped.
Horsetail Creek Bridge: Design Method Calibration and Experimental Results of Structural Strengthening with CFRP and GFRP Laminates
Authors: Kachlakev Damian I.
Published: October 2002

The Horsetail Creek Bridge, constructed in 1912, is located along the Historic Columbia River Highway in Oregon. In a recent rating of bridges, the cross beams of the structure were found to be 50 percent deficient in flexure and 94 percent deficient in shear, mainly due to the traffic loads increase. In order to identify suitable Fiber Reinforced Polymer strengthening system, few commercially available systems were reviewed and alternative designs were carried on. Concurrently, four full size beams were constructed to simulate the retrofit of the bridge. One served as a control, while the other three were reinforced with various configurations of FRP composites. Third point bending tests were conducted. Load, deflection and strain data were collected. Results revealed that addition of either GFRP or CFRP composites provided static capacity increase of 45 percent compared to the control beam. The beam strengthened with CFRP for flexure and GFRP for shear, which simulated the HCB cross beams after the retrofit, exhibited near 100 percent of moment capacity increase. The addition of GFRP for shear alone was sufficient to offset the lack of steel stirrups in the actual bridge, allowing for a conventionally reinforced concrete beam with significant shear deficiency to fail by yielding of the flexural failure. The resulting ultimate deflections of the shear GFRP reinforced beam were nearly twice those of the control shear deficient beam. A design method for flexure and shear was proposed before the onset of this experimental study and used on the HCB. The design procedure for flexure was refined to include provisions for non-crushing failure modes. It allowed for predicting the response of the beam at any applied moment.
Plasma chitotriosidase activity in patients with β‐thalassemia
Authors: Altarescu G. , Rudensky B. , Abrahamov A. , Goldfarb A. , Rund D. , Zimran A. , Elstein D.
Published: October 2002

Variable increases in chitotriosidase levels have been reported in Italian patients with β‐thalassemia major and intermedia. We measured plasma chitotriosidase levels in Israeli patients with β‐thalassemia to ascertain its use as a universal marker of disease and/or response to therapy. Chitotriosidase levels in 39 adults (16–53 years; 30 with β‐thalassemia major, 9 with intermedia), and in 14 children (0.7–15 years; 12 with β‐thalassemia major, 2 with intermedia) were compared with other measures of disease, such as ferritin, hemoglobin, liver function tests, and genotype. Plasma chitotriosidase levels were normal (0.37 ± 0.04 mU/mL) in all children. Twelve adults (31%) had elevated levels (>1.33 mU/mL): 11 patients (37%) with thalassemia major and 1 patient (11%) with thalassemia intermedia. A significant correlation was only found between plasma chitotriosidase levels and ferritin levels, and with mean number of transfusions per year. The patient with the highest chitotriosidase (1,440 nmol/mL/hr) had the highest ferritin (5,175 μg/L), required the most transfusions per year (40), and had abnormal liver tests. Normal chitotriosidase levels in the pediatric cohort and increased levels in only some adults may reflect status of iron overload in macrophages; thus there may be a role for monitoring chitotriosidase in patients with β‐thalassemia. Our results confirm results of the Italian cohort; however, in the latter, a more universal correlation was noted and chitotriosidase levels were much higher. Am. J. Hematol. 71:7–10, 2002. © 2002 Wiley‐Liss, Inc.
Preparation and evaluation of photocrosslinkable chitosan as a drug delivery matrix
Authors: Jameela S.R. , Lakshmi S. , James Nirmala R. , Jayakrishnan A.
Published: October 2002

Epichlorohydrin (1‐chloro‐2,3‐epoxypropane) was reacted with sodium azide in the presence of a phase transfer catalyst to obtain 1‐chloro‐2‐hydroxy‐3‐azidopropane, which was further coupled onto chitosan to prepare a photocrosslinkable derivative of the biopolymer. Elemental analysis and infrared (IR) spectroscopy confirmed the incorporation of azide groups onto chitosan. Films were cast from an aqueous acetic acid solution of azidated chitosan containing a model drug, such as theophylline. Irradiation of the film with ultraviolet (UV) light led to crosslinking of the drug incorporated film. IR spectra indicated complete surface crosslinking within 2 h of irradiation. Release of theophylline from uncrosslinked and crosslinked films was examined in simulated gastric and intestinal fluids without enzymes at 37 °C. The release of the drug from the crosslinked films was slower than the release from uncrosslinked films. Although the system is far from being optimized to obtain sustained release of a pharmacologically active agent for long periods, the data obtained indicate the possibility of developing photocrosslinkable matrices of biopolymers, such as chitosan, for sustained drug delivery with many advantages over chemical crosslinking. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1873–1877, 2002
Water‐vapor‐permeable polyurethane resin
Authors: Chwang C. P. , Lee S. N. , Yeh J. T. , Chen C. Y. , Chao D. Y.
Published: October 2002

The reaction of methylene diphenylene diisocyanate with ethylene glycol, dimethyl dimethoxysilane, dimethyl diethyloxysilene, and other additives in the presence of N,N‐dimethylformamide and toluene to form the structure of water‐vapor‐permeable polyurethane (PU) resin was proven with Fourier transform infrared spectra. Experimental results clearly showed that the amount of oxygen that permeated the film made with the PU resin increased with an increase in the concentration of ethylene glycol, diethylene glycol, or triethylene glycol. This was due to an increased number of hydrophilic groups attached to the backbone of the PU resin molecules. These hydrophilic groups, because of the intermolecular interactions between PU resin molecules, made PU resin molecules form an expanded conformation with large porosities. Interestingly, the water vapor permeability of the PU resin appeared to increase with an increasing concentration of ethylene glycol, dimethyl dimethoxysilane, or dimethyl diethoxysilane but not to increase with an increasing concentration of diethylene glycol, triethylene glycol, or poly(ethylene glycol) with dimethyl dimethoxysilane. The former was due to intermolecular interactions resulting in an expanded conformation with large porosities, but the latter was due to intramolecular interactions resulting in a compact conformation or a micellelike structure with small porosities. Therefore, the water vapor permeability of the former increased, but the latter remained unchanged or decreased. Our experimental results suggest that the use of poly(ethylene glycol) 400, ethylene glycol, dimethyl dimethoxysilane, and other strong hydrophilic compound in the preparation of modified PU resins substantially raises the amount of water vapor diffusing into films made with these resins. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2002–2010, 2002
A polyacrylic acid as a carrier for immobilization of penicillin acylase
Authors: Li Yuanxun , Su Xinqing , Ye Qingling
Published: October 2002

A copolymer of acrylic acid with divinylbenzene was synthesized by suspension polymerization. This polymer is an effective carrier. Penicillin acylase was immobilized on this carrier to convert benzylpenicillin to 6‐aminopenicillanic acid, which may be employed in the manufacture of semisynthetic penicillins. Factors that affect the activity of immobilized penicillin acrylase, such as temperature, pH, and amount of native enzyme, were studied. Under suitable conditions, the activity and activity recovery of the immobilized enzyme were 3100 U/g (dry carrier, p‐dimethylaminobenzaldehyde method) and 59.7%, respectively. The immobilized penicillin acylase shows a remarkable increase in stability. At 40°C and pH 8.0 the value of the kinetic Michaelis–Menten constant (Km) of the immobilized enzyme is 2.8 × 10−3 mol/L, and the value of activation energy of enzyme catalysis is 71.5 kJ/mol. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2067–2069, 2002
Stability constants of polymer‐bound iminodiacetate‐type chelating agents with some transition‐metal ions
Authors: Chen Chuh‐Yean , Chen Chuh‐Yung
Published: October 2002

A chelating vinyl monomer, glycidyl methacrylate (GMA)–iminodiacetic acid (IDA), was formed by the reaction between GMA and IDA. Three polymeric chelating agents, PGMA–IDA, PGMA–IDA‐co‐methyl acrylate (MA), and PGMA–IDA‐co‐acrylamide (AAm), were also synthesized. Acid dissociation constants and stability constants of these chelating agents with Ni(II), Zn(II), and Co(II) were determined by means of potentiometric titration and ultraviolet–visible spectrophotometry, respectively. The values of Ka1 and Ka2 of all the polymeric chelating agents were smaller than those of GMA–IDA. The stability constants of all the polymeric chelating agents were larger than those of GMA–IDA. Increasing the MA content within PGMA–IDA‐co‐MA affected the stability constant only slightly. A proper molar ratio of AAm in PGMA–IDA‐co‐AAm, stability constants was 30–60 times greater than that of GMA–IDA. However, as the molar content of AAm increased, the stability constant of PGMA–IDA‐co‐AAm decreased. The results obtained in the polymer system are explained in terms of the polymer's stereo and entanglement structure, the neighboring effect, and the hydrophobic/hydrophilic nature of MA or AAm. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1986–1994, 2002
Rats can discriminate illuminance, but not magnetic fields, as a stimulus for learning a two‐choice discrimination
Authors: Creim J.A. , Lovely R.H. , Miller D.L. , Anderson L.E.
Published: October 2002

In each of the two experiments, nine rats were trained for 64 trials (eight trials per day) to determine if they could acquire a two‐choice discrimination based on a specified discriminative stimulus (SD). In one experiment, the SD was a change in ambient illumination, while in the second experiment the SD was a change in the combination of sinusoidal 60 Hz and static magnetic field (MF) and any cues attendant to energizing the coils that produced the MF exposure. The rats that had a change in illuminance as the SD learned the two‐choice task easily, P < .001, whereas the rats having a change in MFs as the SD did not. Bioelectromagnetics 23:545–549, 2002. © 2002 Wiley‐Liss, Inc.
A null space algorithm for mixed finite‐element approximations of Darcy's equation
Authors: Arioli Mario , Manzini Gianmarco
Published: October 2002

A null space algorithm is considered to solve the augmented system produced by the mixed finite‐element approximation of Darcy's Law. The method is based on the combination of an orthogonal factorization technique for sparse matrices with an iterative Krylov solver. The computational efficiency of the method relies on a suitable stopping criterion for the iterative solver. We experimentally investigate its performance on a realistic set of selected application problems. Copyright © 2002 John Wiley & Sons, Ltd.
Nonlinear dynamics of EEG in Alzheimer's disease
Authors: Jeong Jaeseung
Published: October 2002

Nonlinear dynamical analysis has been widely applied to a variety of physiological data for last two decades. One of its major contributions is to the electroencephalogram (EEG) in Alzheimer's disease (AD). A number of studies using nonlinear dynamical methods have shown the globally decreased complexity of EEG patterns in AD patients. A prominent decrease in information transmission among cortical areas quantified by information‐theoretic measures like mutual information is also found. These findings indicate decreased nonlinear processes underlying the EEG in AD. This review article focuses on nonlinear EEG abnormalities in AD patients obtained from nonlinear methods and their clinical implications. We suggest that nonlinear dynamical analysis may contribute to a deeper understanding of the neuropathological mechanism of AD in ways that are not possible by conventional spectral analysis. Drug Dev. Res. 56:57–66, 2002. © 2002 Wiley‐Liss, Inc.
Assessment to improve student learning
Authors: Brakke David F. , Brown Douglas T.
Published: October 2002

Effective institutional decision making about budgets, programs, and facilities must be built on the strong foundation of meaningful evaluation.
Clinical significance of interleukin‐6 and interleukin‐6 receptor expressions in oral squamous cell carcinoma
Authors: Wang Yi‐Fen , Chang Shyue‐Yih , Tai Shyh‐Kuan , Li Wing‐Yin , Wang Liang‐Shun
Published: October 2002

Background

Recent studies showed that interleukin‐6 (IL‐6) played a role in tumor development. However, available information about the prognostic significance of IL‐6 and IL‐6 receptors (IL‐6R) for oral squamous cell carcinoma (OSCC) is limited.

Methods

Eighty‐six patients with OSCC were enrolled. Immunohistochemical staining was used to determine IL‐6R expression and in‐situ hybridization for IL‐6 mRNA transcripts in surgical specimens. Clinicopathologic correlation was evaluated by chi‐square test and survival by log rank test.

Results

Expression rates of IL‐6R and IL‐6 mRNA transcripts in tumor specimens were 73.3% and 54.7%, much higher than those in nontumor mucosa (p < .001). IL‐6R overexpression was associated with larger tumors and more advanced histologic grade (p < .05). The presence of IL‐6 mRNA transcripts was inversely correlated with distant metastasis, lymph node involvement, and second primary SCC (p < .05) and predicted better survival (p = .007).

Conclusions

IL‐6‐IL‐6R coexpression was rather high in OSCC, and IL‐6 mRNA transcript expression might influence patient survival. The biologic role of IL‐6‐IL‐6R coexpression in OSCC needs additional investigation. © 2002 Wiley Periodicals, Inc. Head Neck 24: 850–858, 2002
Role of Helicobacter pylori infection among offspring or siblings of gastric cancer patients
Authors: Chang Young‐Woon , Han Yo‐Seob , Lee Dong‐Keun , Kim Hyo‐Jong , Lim Hyun‐Seok , Moon Jeong‐Seop , Dong Seok‐Ho , Kim Byung‐Ho , Lee Joung‐Il , Chang Rin
Published: October 2002

A positive family history is an increased risk factor for gastric cancer within family members, and one of the possible causes of this is the intrafamilial clustering of Helicobacter pylori infection. Our study examined the prevalence of H. pylori infection, serum antibodies to CagA and VacA and atrophic gastritis and/or intestinal metaplasia in the offspring or siblings of gastric cancer patients. A total of 726 subjects included 300 relatives of 300 separate gastric cancer patients and 426 controls. All subjects underwent upper gastrointestinal endoscopic examination with a rapid urease test. Blood samples were obtained to test for the presence of serum antibodies to the CagA and VacA proteins of H. pylori. The prevalence of H. pylori infection was higher in relatives of cancer patients (75.3%) than in controls (60.1%), and the adjusted odds ratio was 2.1 (95% CI 1.5–2.9). When either siblings or 2 or more family members were gastric cancer patients, the prevalence of H. pylori infection was much higher compared to the prevalence in controls. There was no specific relationship between CagA and VacA, and H. pylori infection. Atrophic gastritis and/or intestinal metaplasia were more frequently found in H. pylori‐infected relatives of cancer patients (26.1%) than in H. pylori‐infected controls (12.9%). These results strongly support a role for H. pylori infection in familial aggregation of gastric cancer. The prophylactic eradication of H. pylori infection in the offspring or siblings of gastric cancer patients may be clinically beneficial. © 2002 Wiley‐Liss, Inc.
Micropattern formation of apatite by combination of a biomimetic process and transcription of resist pattern
Authors: Ozawa Naoshi , Yao Takeshi
Published: October 2002

Two kinds of methods combining a biomimetic process and transcription of resist pattern were conducted to form an apatite micropattern. For method 1, apatite nuclei were formed on a resist pattern printed substrate by setting it in contact with CaO‐SiO2‐based glass in a simulated body fluid (SBF) with inorganic ion concentrations nearly equal to those of human blood plasma. Next, apatite was grown from the nuclei by soaking the substrate in an aqueous solution with ion concentrations 1.5 times those of SBF (1.5 SBF). Then, the resist material was dissolved off by organic solvent with the apatite just formed on it. Apatite micropattern transcribing the resist pattern was obtained. For method 2, apatite nuclei were formed on a resist pattern printed substrate by setting it in contact with CaO‐SiO2‐based glass in SBF. Next, the resist material was dissolved off with the apatite nuclei just formed on it. Then, the substrate was soaked in 1.5 SBF to grow the remaining nuclei and an apatite micropattern transcribing the resist pattern was obtained. For both methods, minute apatite patterns with various shapes as straight lines, bending lines, and blocks were clearly formed. The minimum line width of the obtained pattern was 2 μm. These methods are promising for producing multifunctional materials with bioaffinity. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 579–586, 2002
Surface engineering of poly(D,L‐lactic acid) by entrapment of chitosan‐based derivatives for the promotion of chondrogenesis
Authors: Zhu Huiguang , Ji Jian , Lin Rongyi , Gao Changyou , Feng Linxian , Shen Jiacong
Published: October 2002

Chitosan and chitosan–amino acid derivatives were explored to engineer poly(D,L‐lactic acid) (PDL‐LA) as an extracellular matrix‐like surface to promote cell adhesion and growth. Four kinds of chitosan–amino acid derivatives were prepared to mimic the carbohydrate moieties of cell matrix glycoprotein. The chitosan–amino acid derivatives were characterized by using Fourier transform infrared and ultraviolet spectra. The amino acid content on chitosan–amino acid derivatives was determined by using a ninhydrin‐ultraviolet method. A new strategy, entrapment, was therefore used to modify the PDL‐LA membrane with chitosan and chitosan–amino acid derivatives. The results of X‐ray photoelectron spectroscopy, attenuated total reflectance–Fourier transform infrared, and contact angle confirmed that a stable thin film of chitosan and its derivatives can be entrapped on the surface of the PDL‐LA membrane. From the results of chondrocyte cytocompatibility, MTT [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide] assays, and cell morphology, the chitosan–amino acid derivative modified PDL‐LA membranes were shown to promote chondrogenesis. The novel surface treatment method combines the good mechanical property of PDL‐LA with the good cytocompatibility of chitosan derivatives, which may have potential for tissue engineering. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 532–539, 2002
Biocompatibility of dense hydroxyapatite prepared using an SPS process
Authors: Nakahira A. , Tamai M. , Aritani H. , Nakamura S. , Yamashita K.
Published: October 2002

In the present study, the preparation of dense hydroxyapatite (HAp) materials at relative low temperatures using a spark plasma sintering was carried out. The bioactivity of HAp samples prepared by a spark plasma sintering method was investigated by in vitro tests and compared with HAp obtained by a conventional hot‐pressing method. No growth of bone‐like HAp crystals on surface of HAp sintered by a conventional hot‐pressing method at 1200°C was observed after immersion in a simulated body fluid (SBF) for 2 days. However, many large bone‐like HAp crystals were observed on the surface of HAp samples prepared by a spark plasma sintering at 1200°C after 2 days in the SBF immersion test. Especially, the negatively charged surface of the HAp samples prepared by spark plasma sintering was covered with larger HAp crystals compared with the positively charged surface. The electric poling of HAp was measured using a thermally simulated current technique. This rapid growth of bone‐like HAp crystals of the HAp samples made by spark plasma sintering was believed to be related with the OH− and/or Ca ion deficiency at the grain boundaries of the HAp matrix grains as well as a small electric poling effect resulting during the spark plasma sintering process. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 550–557, 2002
Dynamic structural changes of synaptic contacts in the visual system of insects
Authors: Pyza Elzbieta
Published: October 2002

The visual system of insects provides an excellent model to study processes of transduction and transmission of photic information, synaptogenesis, synaptic plasticity, and wiring between photoreceptors and their visual interneurons in the optic lobe. This review describes synaptic contacts between photoreceptors and other neurons in the visual system of insects, especially in the fly's first optic neuropile (the lamina), and summarizes changes observed in the synapses of visual cells that have been reported both in phylogeny and ontogeny, and also examples of synaptic plasticity in adult insects that have been evoked by intrinsic and extrinsic factors. Plasticity observed in synapses of the insect's visual system seems to exemplify not only synaptic contacts in insects but, given that similar examples of plasticity have been found in other animal groups, may also be a general phenomenon in the nervous system. Microsc. Res. Tech. 58:335–344, 2002. © 2002 Wiley‐Liss, Inc.
Feline immunodeficiency virus vectors. Gene transfer to mouse retina following intravitreal injection
Authors: Derksen Todd A. , Sauter Sybille L. , Davidson Beverly L.
Published: October 2002

Background

Transduction of the murine retinal pigmented epithelium (RPE) with adenovirus vectors requires technically difficult and invasive subretinal injections. This study tested the hypothesis that recombinant vectors based on feline immunodeficiency virus (FIV) could access the retina following intravitreal injection.

Methods

FIV vectors expressing E. coli β‐galactosidase (FIVβgal) were injected alone, or in combination with adenovirus vectors expressing eGFP, into the vitreous of normal mice and eyes evaluated for transgene expression. In further studies, the utility of FIV‐mediated gene transfer to correct lysosomal storage defects in the anterior and posterior chambers of eyes was tested using recombinant FIV vectors expressing β‐glucuronidase. FIVβgluc vectors were injected into β‐glucuronidase‐deficient mice, an animal model of mucopolysacharridoses type VII.

Results

The results of this study show that similar to adenovirus, both corneal endothelium and cells of the iris could be transduced following intravitreal injection of FIVβgal. However, in contrast to adenovirus, intravitreal injection of FIVβgal also resulted in transduction of the RPE. Immunohistochemistry following an intravitreal injection of an AdeGFP (adenovirus expressing green fluorescent protein) and FIVβgal mixture confirmed that both viruses mediated transduction of corneal endothelium and cells of the iris, while only FIVβgal transduced cells in the retina. Using the β‐glucuronidase‐deficient mouse, the therapeutic efficacy of intravitreal injection of FIVβgluc (FIV expressing β‐glucuronidase) was tested. Intravitreal injection of FIVβgluc to the eyes of β‐glucuronidase‐deficient mice resulted in rapid reduction (within 2 weeks) of the lysosomal storage defect within the RPE, corneal endothelium, and the non‐pigmented epithelium of the ciliary process. Transgene expression and correction of the lysosomal storage defect remained for at least 12 weeks, the latest time point tested.

Conclusion

These studies demonstrate that intravitreal injection of FIV‐based vectors can mediate efficient and lasting transduction of cells in the cornea, iris, and retina. Copyright © 2002 John Wiley & Sons, Ltd.
Changing molecular epidemiology of hepatitis C virus infection in Northeast Italy
Authors: Dal Molin Gianna , Ansaldi Filippo , Biagi Claudia , D'Agaro Pierlanfranco , Comar Manola , Crocè Lory , Tiribelli Claudio , Campello Cesare
Published: October 2002

To assess HCV genotype distribution and its determinants, 318 consecutive HCV RNA positive patients were examined. Subtype 1b infection was the most prevalent (35.5%), followed by subtype 1a (22%), 3a (21.4%) and 2 genotype (21.3%). Subtypes 1a, 1b and 3a had a comparable prevalence (30–35%) in the 0–15‐, 16–30‐ and 31–45‐year age groups. In subjects older than 45 years, genotype 2 prevalence increased, whereas subtype 1a and 3a infections decreased markedly. In this age group types 1b and 2 accounted for a prevalence of more than 90% in a comparable proportion. Genotype prevalence rates according to different risk factors were different statistically (P < 0.001): subtype 1a and 3a infections were predominant in injection drug users (42.9% and 37.7%, respectively), whereas community acquired infections and infections in patients with a history of transfusion were caused mainly by subtype 1b (38.5% and 66.6%, respectively). Logistic regression showed that age and injection drug use are independent determinants of genotype distribution. J. Med. Virol. 68:352–356, 2002. © 2002 Wiley‐Liss, Inc.
The confounding role of personality and trait affectivity in the relationship between job and life satisfaction
Authors: Heller Daniel , Judge Timothy A. , Watson David
Published: October 2002

Previous research has demonstrated a strong positive relationship between job and life satisfaction. Traditionally, this relationship has been explained in terms of a spillover model, wherein job experiences spill over onto life, and vice versa. This study directly tests a different explanation for this relationship: personality traits that influence both job and life satisfaction. In a longitudinal test with multisource data, three typologies, which were shown by past research to be linked to both job and life satisfaction, were examined: Big Five, positive and negative affectivity, and core self‐evaluations. One hundred and fifty‐three university employees working in a diverse set of occupations were surveyed twice, with a six month time interval; the first survey also included a second questionnaire to be completed by a ‘significant other.’ Analyses of concurrent and prospective zero‐order and partial correlations, as well as structural equation modeling, supported the hypothesized confounding role of all three typologies, especially core self‐evaluations. Though controlling for personality reduced the magnitude of the job–life satisfaction relationship, it did not entirely eliminate it. Overall, the results suggest the presence of both dispositional and environmental factors in job and life satisfaction. Finally, implications for organizational practice and theory development are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Fluorescence probes based on 9‐acridyl derivatives of aromatic amines for monitoring free‐radical polymerization
Authors: Bajorek Agnieszka , Ciepluch Marcin , Pączkowski Jerzy
Published: October 2002

The series of 9‐acridyl derivatives of aromatic amines have been investigated as fluorescent probes for monitoring the progress of free‐radical polymerization. This study on the changes in the fluorescence intensity and spectroscopic shift of specific compounds was carried out during thermally initiated polymerization of methyl methacrylate and photoinitiated polymerization of 2‐ethyl‐2‐(hydroxymethyl)‐1,3‐propanediol triacrylate‐1‐methyl‐2‐pyrrolidonone mixture. The purpose of this investigation was to find a relationship between the changes in the shape and intensity of fluorescent probes and the degree of monomer conversion into a polymer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3481–3488, 2002
Synthesis and photoactivity of novel 5‐arylthianthrenium salt cationic photoinitiators
Authors: Crivello James V. , Ma Junqing , Jiang Faming
Published: October 2002

5‐Arylthianthrenium salts are a class of efficient triarylsulfonium salt photoinitiators for cationic polymerization. These compounds were prepared by a simple, straightforward, versatile, and high yield route. The new photoinitiators were characterized by standard analytical and spectroscopic techniques, and their activity as cationic photoinitiators was compared with related triarylsulfonium salts of similar structures using Fourier transform real‐time infrared spectroscopy. Through the use of electron‐transfer photosensitizers, the response of these photoinitiators can be readily spectrally broadened into the long‐wavelength UV–visible regions of the spectrum. The results obtained suggest that 5‐arylthianthrenium salts are potential replacements for now available triarysulfonium salt photoinitiators in many applications. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3465–3480, 2002
Model for the fracture energy of glassy polymer–polymer interfaces
Authors: Benkoski J. J. , Fredrickson G. H. , Kramer E. J.
Published: October 2002

The increase in the interfacial fracture energy (Gc) with increasing interfacial width (ai) goes through a transition at a critical value of ai that is unique to each polymer–polymer system. This transition point does not scale with the bulk entanglement spacing (dt) for different systems, implying that the role of chain friction in reinforcing these interfaces is more important than previously thought. A theoretical model has been developed to calculate Gc as a function of the interfacial stress transfer due to individual polymer chains. When including the effects of chain friction only, the model reproduces the nonuniversal behavior of Gc with respect to ai/dt but yields poor fits for ai/dt > 1. The effects of entanglements are then added by calculating the fraction of entangled chains as a function of ai/dt. This contribution, although not material specific, matches the qualitative behavior of Gc for large values of ai/dt. When both contributions are included in the model, excellent fits are obtained for all data sets. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2377–2386, 2002
Providing internet lessons to oncology patients and family members: a shared project
Authors: Edgar Linda , Greenberg Arlene , Remmer Jean
Published: October 2002

The paper describes the steps in a pilot study taken to develop and evaluate an Internet intervention for cancer patients and family members. The intervention was a shared project of two hospital departments; a volunteer oncology support service, Hope & Cope, and the Health Services Library. Forty subjects were surveyed on their computer use and interest, and of these, half used the Internet to access health and medical information. Of the 40 subjects, 28 participated in an innovative, one‐to‐one teaching session with a medical librarian where they learned to access Internet sites to find information specific to their needs and subsequently be more confident in their perceived ability to evaluate the information received. Follow up interviews found that the sessions were well received and at two months follow‐up the participants attributed their positive well being in large part to the intervention. Internet use by oncology patients and family members in conjunction with skilled help has the potential to contribute in a timely fashion to the well being of those with cancer. Copyright © 2002 John Wiley & Sons, Ltd.
Quantitative detection of salmeterol after inhalation in equine urine by liquid chromatography/tandem mass spectrometry
Authors: Van Eenoo P. , Deventer K. , Delbeke F. T.
Published: October 2002

A sensitive, accurate and precise liquid chromatography/tandem mass spectrometry (LC/MS2) method was developed for the quantification of salmeterol in the urine of horses. The method consists of a liquid‐liquid extraction with tert‐butylmethyl ether and isopropanol at pH 12 after enzymatic hydrolysis. The extracts are analysed using an LC/MS system equipped with an electrospray ionisation (ESI) probe. Method validation showed excellent linearity, specificity, accuracy, precision and intra‐laboratory repeatability and reproducibility. The limit of quantitative detection was 0.25 ng/mL and the limit of detection was 0.125 ng/mL. The excretion profile was determined after administration of 500 µg salmeterol (Serevent®) to four standard‐bred mares via a metered dose inhaler (MDI) with an Equinehaler® adapter. Salmeterol was detected from 1 h until 12 h post‐administration. Maximum urinary concentrations varied between 2.3 and 14.9 ng/mL. Copyright © 2002 John Wiley & Sons, Ltd.
Adaptive regulation of cascade systems with nonlinear parameterization
Authors: Lin Wei , Qian Chunjiang
Published: October 2002

This article provides a solution to the problem of global adaptive regulation, for a class of nonlinearly parameterized cascade systems including feedback linearizable and minimum‐phase systems with nonlinear parameterization. The solution is derived by using a novel parameter separation technique combined with a feedback domination design. We remove all the restrictive conditions previously imposed on the unknown parameters, such as linear parameterization or convex/concave parameterization conditions, which have been commonly assumed so far in the literature of nonlinear adaptive control. Copyright © 2002 John Wiley & Sons, Ltd.
On‐line learning neural networks for sensor validation for the flight control system of a B777 research scale model
Authors: Campa Giampiero , Fravolini Mario L. , Seanor Brad , Napolitano Marcello R. , Gobbo Diego Del , Yu Gu , Gururajan Srikanth
Published: October 2002

This paper focuses on the analysis of a scheme for sensor failure, detection, identification and accommodation (SFDIA) using experimental flight data of a research aircraft model. Recent technical literature has shown the advantages of time‐varying estimators and/or approximators. Conventional approaches are based on different versions of observers and Kalman filters while more recent methods are based on different approximators based on neural networks (NNs). The approach proposed in the paper is based on the use of on‐line learning nonlinear neural approximators.

The characteristics of three different neural architectures were compared through different sensor failures. The first architecture is based on a multi layer perceptron (MLP) NN trained with the extended back propagation algorithm (EBPA). The second and third architectures are based on a radial basis function (RBF) NN trained with the minimal resource allocating network (MRAN) and extended‐MRAN (EMRAN). The MRAN and EMRAN algorithms have recently been developed for RBF networks and have shown remarkable learning capabilities at a fraction of the memory requirements and computational effort typically associated with conventional RBF NNs.

The experimental data for this study are flight data acquired from the flight‐testing of a $$1 \over 24$$th semi‐scale B777 research model designed, built, and flown at West Virginia University (WVU). Copyright © 2002 John Wiley & Sons, Ltd.
Fisher information matrix for non‐linear mixed‐effects models: evaluation and application for optimal design of enoxaparin population pharmacokinetics
Authors: Retout Sylvie , Mentré France , Bruno René
Published: October 2002

We address the problem of the choice and the evaluation of designs in population pharmacokinetic studies that use non‐linear mixed‐effects models. Criteria, based on the Fisher information matrix, have been developed to optimize designs and adapted to such models. We optimize designs under different constraints and evaluate them for a population pharmacokinetics study, within a new phase III trial of enoxaparin, a low molecular weight heparin. To do this, we approximate the expression of the Fisher information matrix for non‐linear mixed‐effects models including the residual error variance as a parameter to be estimated. We use the Fedorov–Wynn algorithm to minimize the inverse of the determinant of this matrix as required by the D‐optimality criterion. Two optimal designs, as well as a design defined by pharmacologists, are evaluated by the simulation of 30 replicated data sets with NONMEM; all designs involve 220 patients with four measurements per patient. We also evaluate the relevance of the standard errors of estimation given from the Fisher information matrix by comparison with those given by NONMEM. The three designs provide more precise population parameter estimates; the optimal design gives the best precision and offers a simple clinical implementation. The expected standard errors given by the information matrix are close to those obtained by NONMEM on the simulation. Moreover, the proposed criterion of D‐optimality appears to be a good measure to compare designs for population studies. Copyright © 2002 John Wiley & Sons, Ltd.
Exploring the genealogy of systems thinking
Authors: Hammond Debora
Published: October 2002

As a plenary address at the 2001 Annual Conference of the International Society for the Systems Sciences (ISSS), this paper was intended to initiate an interactive exploration into the roots of systems thinking. Beginning with a summary of the key influences in the development of the author's own understanding of systems, the paper continues with an overview of developments in the broad variety of disciplinary fields that contributed to the elaboration of systems concepts. Following these introductory reflections, the paper provides a brief discussion of the primary concerns of the original founders of the ISSS (Ludwig von Bertalanffy, Kenneth Boulding, Ralph Gerard, James G. Miller and Anatol Rapoport). Those who attended the conference were then asked to consider the evolution of their own understanding of the meaning and significance of systems thinking by responding to the following questions: (1) Through what academic discipline or occupational field were you originally introduced to systems ideas? (2) Which systems thinkers have been most influential in the evolution of your own thinking about systems? (3) What kinds of questions motivated your interest in systems? (4) What kinds of problems were you seeking to address? (5) Has your concern with systems ideas been primarily theoretical or practical? A brief summary of answers to these questions is included in the concluding remarks. Copyright © 2002 John Wiley & Sons, Ltd.
The expression of the non‐receptor tyrosine kinases Arg and c‐abl is differently modulated in B lymphoid cells at different stages of differentiation
Authors: Bianchi Cristina , Muradore Ivan , Corizzato Matteo , Cornacchini Giorgia , Beretta Luca , Erba Eugenio , Del Monte Ugo , A. Perego Roberto
Published: October 2002

The products of the human ARG gene and the human ABL gene characterize the Abelson family of non‐receptor tyrosine protein kinases. Both genes are ubiquitously expressed. The interactions of these two similar protein kinases are still not well known, although it has been suggested that they could cooperate, with redundant actions, to provide intracellular signals in the cells. Lymphopenia occurs in mice with homozygous disruption of c‐abl, indicating that in certain tissues Arg is unable to substitute c‐abl functions. In B and T lymphoid cell lines at different stages of differentiation, we studied, by a reverse transcriptase‐competitive polymerase chain reaction and Western blotting, Arg and c‐abl in order to evaluate whether the expression pattern of the two genes could give insight as to why they do not exhibit overlapping roles in lymphocytes and whether the product levels of the two genes are related to lymphoid differentiation. The data showed that their expression is differently modified in lymphoid B cell lines. The highest Arg transcript and protein levels are in the mature B cells.