bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of nitrile–butadiene rubber layered silicate nanocomposites with silane coupling agent
Authors: Kim Jin‐Tae , Lee Dong‐Yeoul , Oh Taeg‐Su , Lee Dong‐Ho
Published: June 2003

Nanocomposites of organophilic montmorillonite (C18‐MMT), nitrile–butadiene rubber (NBR), and a coupling agent were produced during a melt compounding process at room temperature. During the process, it was clearly observed that organo‐MMT particles were exfoliated into nanoscale layers of approximately 1–30 nm thickness, in addition to their original 40 μm thickness. These MMT layers were uniformly dispersed in the NBR matrix. The effects of a coupling agent such as 3‐(mercaptopropyl)trimethoxy silane in C18‐MMT/NBR nanocomposites were studied. The C18‐MMT/NBR nanocomposites in the presence of the coupling agent were identified and characterized by X‐ray diffraction, transmission electron microscopy, a universal testing machine, thermogravimetric analysis, and IR spectroscopy. It was observed that an additional silane coupling agent, 3‐(mercaptopropyl)trimethoxy silane, enhanced the chemical interaction and was accompanied by the formation of SiOSi coupling bonds between C18‐MMT and the coupling agent and SiC coupling bonds between NBR and the coupling agent. This work resulted in improved properties of organo‐MMT/NBR nanocomposites because of the nanoscale effects and strong interaction of the coupling bonds between NBR and organo‐MMT. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2633–2640, 2003
Ion‐exchange resins. II. Acrylamide crosslinked copolymers as precursors for some ion exchangers
Authors: Dragan Stela , Dinu Maria V. , Vlad Cristina D.
Published: June 2003

Crosslinked copolymers of acrylamide (AA) and ethylacrylate and some ion exchangers derived from them containing either primary amine groups, obtained by the Hofmann degradation of the amide groups, or carboxylic groups, obtained by the alkaline hydrolysis of the ester groups, were studied. Divinylbenzene and N,N′‐methylenebisacrylamide were used as crosslinkers. The starting copolymers and the corresponding ion exchangers were characterized by IR spectroscopy, swelling behavior, and thermogravimetric analysis. The ion‐exchanger properties were correlated with the crosslinker nature and the chemical reactions performed on the AA copolymers. The average molecular weight between two crosslinks, determined from the swelling data in water, was compared with that calculated on the basis of the copolymerization stoichiometry only for the carboxylic cation exchangers. In this way, the preservation of the crosslink density after the hydrolysis was revealed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2701–2707, 2003
Study of fluorescence from fluorescent dye‐based polyurethane ionomer
Authors: Wang C. L. , Zhang Z. J. , Yang C. Y. , Chao D. Y.
Published: June 2003

6‐Amino‐2‐(3‐chloro‐2‐hydroxy‐propyl)‐ benzo[de]isoquinoline‐1,3‐dione (DYE‐A) and 2‐benzyl‐6‐hydroxy‐benzo[de]isoquinoline‐1,3‐dione (DYE‐B) have been successfully synthesized in our lab, and their structures have been proven by IR, NMR, and mass spectra. The fluorescence performance appears to be better for DYE‐A than for DYE‐B as a result of DYE‐A having more electron donating substituents that are strongly excited when absorbing UV light. These fluorescent dyes have further reacted with toluene diisocyanate and other additives to form the fluorescent dye‐based polyurethane (PU) ionomer molecules, and the structures of these molecules have been demonstrated by IR spectra. In aqueous solution, our experimental results indicate that the fluorescence performance is seen to be better for DYE‐A than for DYE‐B. Increased concentration of DYE‐A molecule attached to the backbone of the PU ionomer molecule may reduce the fluorescence performance of this PU ionomer molecule, resulting from the intramolecular interaction between ionomer molecule itself. For the fluorescent dye‐based PU ionomer molecule system, the average particle size of the fluorescent dye‐based PU ionomer molecule in water increases with increasing concentration of the fluorescent dyes, as a result of increased free volume of the ionomer molecules. Our experimental results also illustrate that the tensile strength of self‐cured film made by the fluorescent dye‐based PU ionomer appears to increase with an increase in the concentration of DYE‐A. This is the result of increased intermolecular interaction between ionomer molecules. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2723–2737, 2003
Poly(vinyl alcohol)/poly(vinyl pyrrolidone) interpenetrating polymer network: Synthesis and pervaporation properties
Authors: Lu Jie , Nguyen Quangtrong , Zhou Jiqing , Ping Zheng‐Hua
Published: June 2003

Novel interpenetrating polymer network membranes were made from poly(vinyl alcohol)/poly(vinyl pyrrolidone) blends of different compositions. The two polymer components were independently crosslinked chemically with glutaraldehyde and photochemically with 4,4′‐diazostilbene‐2,2′‐disulfonic acid disodium salt. The membrane performances were studied in pervaporation of tetrahydrofuran (THF)/water and THF/methanol mixtures. It was found that the membranes were excellent in THF dehydration, but much less efficient for the separation of THF/methanol mixtures. The pervaporation results were consistent with the membrane swelling data. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2808–2814, 2003
Using internal magnetic fields to obtain pore size distributions of porous media
Authors: Song Yi‐Qiao
Published: June 2003

This article reviews an NMR method, Decay due to Diffusion in Internal Field (DDIF), to obtain detailed pore size information in the fluid‐filled porous media. This method detects molecular diffusion of the fluid in the pore space subject to the magnetic field inhomogeneity produced by the susceptibility contrast between the fluid and the solid materials. We discuss the use of stimulated echoes to create and detect the magnetization modulation, different encoding regimes (weak and strong), and the analysis of the multiexponential decay using Laplace inversion. We also discuss briefly the theoretical treatment of diffusion in porous media using the eigenmode formalism. We note that the application of this technique does not use applied field gradients. © 2003 Wiley Periodicals, Inc. Concepts Magn Reson 18A: 97–110, 2003
Transmission on indoor power lines: from a stochastic channel model to the optimization and performance evaluation of multicarrier systems
Authors: Degardin Virginie , Lienard Martine , Degauque Pierre
Published: June 2003

This paper deals with optimization and performance evaluation of multicarrier transmissions on indoor power lines, taking the actual channel characteristics into account. From intensive measurements of noise on lines, the most significant parameters of impulsive noise were defined and classified, and then a statistical study was carried out. The other types of noise, i.e. narrow band and coloured noise have also been characterized. In like manner, the transfer functions between two points of a power line network have been measured. From all these data, a stochastic channel model representative of the environment is built and implemented in a software tool simulating the link. Various transmission schemes have been considered to mitigate the effects on one hand of the stationary noise, the channel frequency selectivity and of the change of its state, and on the other, on the impulsive noise. These techniques are optimized for the indoor power line environment and their performances, expressed in terms of bit error rate, are compared. Copyright © 2003 John Wiley & Sons, Ltd.
Granulysin in human serum as a marker of cell‐mediated immunity
Authors: Ogawa Kazuyuki , Takamori Yasushi , Suzuki Kunou , Nagasawa Masayuki , Takano Shoichi , Kasahara Yoshihito , Nakamura Yoshiko , Kondo Shigemi , Sugamura Kazuo , Nakamura Masataka , Nagata Kinya
Published: June 2003

Granulysin is a cytolytic granule protein of natural killer (NK) cells and cytotoxic T lymphocytes (CTL) with a broad range of antimicrobial and tumoricidal activities. Two molecular forms of granulysin, the 15‐kDa precursor and 9‐kDa mature form, are produced in these cells. In this study, we developed monoclonal antibodies against granulysin and found that the 15‐kDa granulysin is spontaneously secreted by peripheral blood NK and T cells via a non‐granule exocytotic pathway. When NK cells killed the target cells, the released granulysin levels in culture supernatants significantly increased through the granule exocytosis. The granulysin protein was found in the sera of healthy individuals at an average concentration of 3.7±3.2 ng/ml (age 0–99 years, n=244). The serum levels of granulysin were transiently highly elevated among patients with acute viral infections. In addition, the serum granulysin levels in patients with severe immunodeficiency treated bycell therapy fluctuated proportionately to the improvement of other immunological parameters. Our results suggest that granulysin is well associated with diverse activities of NK cells and CTL in physiological and pathological settings and could be a useful novel serum marker to evaluate the overall status of host cellular immunity.
Correction: Monitoring gene expression of TNFR family members by β‐cells during development of autoimmune diabetes (Eur. J. Immunol. 7/2003)
Authors: Walter U. , Franzke A. , Sarukhan A. , Zober C. , von Boehmer H. , Buer J. , Lechner O.
Published: June 2003

Vol. 30(4) 2000, pp 1224‐1232

In this article, the name of Anke Franzke was unfortunately published incorrectly: the correct spelling is as given here.
Glacial outlet valley size–ice drainage area relationships: some considerations
Authors: Brook Martin S. , Brock Ben W. , Kirkbride Martin P.
Published: June 2003

Previous work indicates that large variations in the power‐law relationship, relating glacial outlet valley size to ice drainage area, may occur between different glaciological settings. In this paper, we take issue with methods used to quantify the relationships of outlet valley size to drainage area size and propose a general method for comparing power‐law relationships between study areas, to determine whether or not such power‐law scalings are similar. Based on this method, we demonstrate that outlet valleys have a similar sensitivity to variation in ice‐contributing area irrespective of their glaciological setting, contrary to earlier findings. Minor variation in such relationships may reflect the different lithological and glaciological settings of the study sites and provide an insight into the physics of glacial erosional development of landscapes. Despite their limitations, we conclude that power‐law relationships are valid and, when interpreted carefully, provide a useful basis for comparing the efficiency of glacial erosion processes in different locations. Copyright © 2003 John Wiley & Sons, Ltd.
Investigation of spatially distributed braided river flows using a two‐dimensional hydraulic model
Authors: Nicholas A. P.
Published: June 2003

This paper reports the application of a two‐dimensional hydraulic model to a braided reach of the Avoca River, New Zealand. Field measurements of water surface elevation, depth and velocity obtained at low flow were used to validate the model and to optimize the parameterization of bed friction. The main systematic trends in the measured flow variables are reproduced by the model. However, field data are characterized by greater spatial variability than model output reflecting differences in the scale of processes measured in the field and represented by the model. Additional model runs were conducted to simulate flow patterns within the study reach at five higher discharges. The purpose of these simulations was to evaluate the potential for using two‐dimensional hydraulic models to quantify the reach‐scale hydraulic characteristics of braided rivers and their dependence on discharge. Changes in flow depth and velocity with increasing discharge exhibit trends that are consistent with the results of previous field investigations, although the tendency for the wetted area of the braidplain within particular depth and velocity categories to remain fixed as discharge rises, as has been noted for several braided rivers in New Zealand, was not observed. Modelled shear stress frequency distributions fit gamma functions that incorporate a distribution shape parameter, the value of which follows clear systematic trends with rising discharge. These results illustrate both the problems of, and potential for, using two‐dimensional hydraulic models in braided river applications. This leads to something of a paradox in that while such models provide a means of generating hydraulic information that would be difficult to obtain in the field at an equivalent spatial resolution, they are, due to the problems inherent to data collection, difficult to validate conclusively. Despite this limitation, the application of spatially distributed models to investigate relationships between discharge and reach‐scale form and process variables appears to have considerable potential. Copyright © 2003 John Wiley & Sons, Ltd.
Allocating health care resources when people are risk averse with respect to life time
Authors: Hoel Michael
Published: June 2003

The criterion of cost‐effectiveness in health management may be given a welfare‐theoretical justification if people are risk neutral with respect to life years. With risk aversion, the optimal allocation of health expenditures changes: Compared to the cost‐effective allocation, more resources should be allocated to health conditions for which the expected outcomes even after treatment are worse than average. The consequences of medical interventions are usually not known with certainty. Given this type of uncertainty, simple application of cost‐effectiveness analysis would recommend maximization of expected health benefits given the health budget. We show that when people are risk averse with respect to the number of life years they live, the uncertainty associated with different types of interventions should play a role in allocating the health budget. Copyright © 2002 John Wiley & Sons, Ltd.
Price elasticity and pharmaceutical selection: the influence of managed care
Authors: Domino Marisa Elena , Salkever David S.
Published: June 2003

State Medicaid programs are turning increasingly to managed care to control expenditures, although the types of managed care programs in use have changed dramatically. Little is known about the influence of the shifting Medicaid managed care arena on treatment decisions. This paper investigates factors affecting the selection of treatments for depression by providers participating in either of two Medicaid managed care programs. Of particular interest is the influence of medication price on the choice of treatment, since one vehicle through which managed care organizations can reduce total expenditures is by increasing the price sensitivity of participating providers. We take a new approach by phrasing the problem as a discrete choice, using a nested multinomial logit model for the analyses. Contrary to earlier literature, we find some evidence that physicians in both programs do take price into consideration when selecting among treatment options. HMO providers in particular demonstrate increased price sensitivity in the two most commonly prescribed categories of antidepressants. Copyright © 2002 John Wiley & Sons, Ltd.
Long‐term transgene expression can be mediated in the brain by adenoviral vectors when powerful neuron‐specific promoters are used
Authors: Glover Colin P. J. , Bienemann Alison S. , Hopton Margaret , Harding Thomas C. , Kew James N. , Uney James B.
Published: June 2003

Background

Adenoviral (Ad) vectors are one of the most widely used tools for modelling gene therapy strategies. However, they have not been used in long‐term models of neurological disease, as the period of time for which they mediate strong transgene expression is limited and/or variable. In this study we investigated the longevity of transgene expression in the brain when the powerful neuron‐specific Ad‐synapsin (Sy)‐EGFP‐woodchuck hepatitis virus post‐transcriptional regulatory element (WPRE) vector cassette is used at titres that do not elicit an immune response.

Methods

Adenoviral vectors expressing enhanced green fluorescent protein (EGFP) under the control of either the hCMV, hCMV‐WPRE, Sy or Sy‐WPRE promoter were constructed. These vectors were injected into the dentate gyrus region of hippocampus and transgene expression and immune cell infiltration assessed by fluorescence microscopy and immunocytochemical techniques, respectively.

Results

The quantitative analysis of EGFP expression showed that there was no significant change in synapsin or synapsin‐WPRE driven transcription 9 months after injection when compared with expression levels obtained 3 days after injection. However, when the hCMV promoter or the hCMV‐WPRE promoter cassette drove transgene expression, there was a dramatic fall in expression levels and very little expression was seen 9 months post‐transfection.

Conclusions

This study shows that non‐integrating vectors can be used to mediate powerful, long‐term episomal transgene expression in neurones. This work has important implications for neuronal gene therapy and is of relevance to studies investigating memory, behaviour and neuronal gene function. Copyright © 2003 John Wiley & Sons, Ltd.
Local control of parameningeal rhabdomyosarcoma: Outcomes in non‐complete responders to chemoradiation
Authors: Paulino Arnold C. , Bauman Nancy , Simon James H. , Nguyen Thanh X. , Ritchie Justine M. , Tannous Raymond
Published: June 2003

Purpose

To determine whether there is a role for surgery in Group III and IV patients with residual parameningeal rhabdomyosarcoma (PM‐RMS) after radiotherapy (RT).

Materials and Methods

From 1965 to 2000, 29 patients with PM‐RMS (Group III 27, Group IV 2) were diagnosed and treated with RT at the University of Iowa. All patients received chemotherapy consisting of vincristine, dactinomycin, and cyclophosphamide (VAC) in 17 (59%), VAC + doxorubicin in six (21%), VC + doxorubicin in three (10%), and other in three. RT was given to the primary site. Median dose was 50.4 Gy (range, 41.4–65 Gy). Two had hyperfractionated RT (59.4 Gy in 54 fractions). Median follow‐up time for surviving patients was 17.9 years (range, 1.5–31.5 years).

Results

The 2‐ and 5‐year overall survival rates were 78.9% and 45.7% while the 2‐ and 5‐year freedom from local progression rates were 56.8% and 42.1%. For the 11 patients who did not achieve a complete response to chemoradiotherapy at the primary site, eight underwent surgical resection 1.5–7 months after RT. The 2‐ and 5‐year survival rates for the eight who had a surgical salvage were 100% and 60%. None of the other three survived. Six of 18 patients (33%) relapsed at the primary site after a complete response to chemoradiation and all died.

Conclusion

Surgical salvage after an incomplete response to chemoradiation in PM‐RMS is feasible and can be curative in some cases. Med Pediatr Oncol 2003;41:118–122. © 2003 Wiley‐Liss, Inc.
Third‐order nonlinear optical properties of parabolic and semiparabolic quantum wells
Authors: Wang Guang‐Hui , Guo Qi , Guo Kang‐Xian
Published: June 2003

A detailed procedure for the calculation of the third‐harmonic‐generation susceptibility tensor is given in parabolic and semiparabolic quantum wells, and an analytic formula for the third‐harmonic‐generation susceptibility is obtained by the compact density matrix approach and an iterative procedure. Finally, numerical results are presented for typical GaAs/AlGaAs parabolic and semiparabolic quantum wells. The calculated results show that the third‐harmonic‐generation susceptibilities in parabolic quantum wells are over one order of magnitude greater than in semiparabolic quantum wells, and are over eight orders of magnitude greater than in bulk GaAs. In addition, the third‐harmonic‐generation susceptibilities are related to the parabolic confinement frequency and the relaxation rate.
Moving screw dislocations in piezoelectric bimaterials
Authors: Wu Xiang‐Fa , Dzenis Yuris A. , Zou Wen‐Sheng
Published: June 2003

An explicit solution for a moving screw dislocation in a piezoelectric bimaterial is given by means of complex variables. The electroelastic fields and forces acting on the moving dislocation are obtained in closed form. As special cases, solutions for a moving screw dislocation in a piezoelectric half‐plane with a free or rigid surface are obtained explicitly.
Mobility control: How injected surfactants and biostimulants may be forced into low‐permeability units
Authors: Jackson Richard E. , Dwarakanath Varadarajan , Meinardus Hans W. , Young Carl M.
Published: June 2003

Recovering dense nonaqueous‐phase liquid (DNAPL) remains one of the most difficult problems
facing the remediation industry. Still, the most common method of recovering DNAPL is to physically remove the
contaminants using common technologies such as total fluids recovery pumps, vacuum systems, and
“pump‐and‐treat.” Increased DNAPL removal can be attained using surfactants to
mobilize and/or solubilize the pollutants. However, very little is understood of the methods developed by
petroleum engineers beginning in the 1960s to overcome by‐passed, low‐permeability zones in
heterogeneous oil reservoirs. By injecting or causing the formation of viscous fluids in the subsurface,
petroleum engineers caused increased in‐situ pressures that forced fluid flow into low permeability units
as well as the higher permeability thief zones. Polymer flooding involves injecting a viscous aqueous polymer
solution into the contaminated aquifer. Foam flooding involves injecting surfactant to decontaminate the
high‐permeability zones and then periodic pulses of air to cause a temporary viscous foam to form in the
high‐permeable zones after all DNAPL is removed. Later surfactant pulses are directed by the foam into
unswept low‐permeable units. These methods have been applied to DNAPL removal using surfactants but they
can also be applied to the injection of bio‐amendments into low‐permeability zones still requiring
continued remediation. Here we discuss the principles of mobility control as practiced in an alluvial aquifer
contaminated with chlorinated solvent and coal tar DNAPLs as well as some field results. © 2003 Wiley
Periodicals, Inc.
Electro‐Thermal Dynamic Stripping Process for in situ remediation under an occupied apartment building
Authors: McGee Bruce C.W.
Published: June 2003

The implementation and performance results of the Electro‐Thermal Dynamic Stripping Process
(ET‐DSP™) used in combination with high‐vacuum dual‐phase extraction are
presented here. The technology was selected to remove vapor pressure‐sensitive benzene, toluene, ethyl
benzene, and xylene (BTEX) compounds from under an occupied residential apartment building. Operating
within several engineering, environmental, and safety constraints, a design was developed to conduct electrical
heating and in situ extraction operations without disruption of the daily activities of the residents within the
apartment complex and general area. The results consistently showed a significant reduction in the concentration
of hydrocarbons with non‐detectable levels being achieved in all of the samples that were tested. This is
a direct result of a substantial temperature increase of the soil and concurrent increase in the hydrocarbon
vapor pressure from the ET‐DSP™ system. © 2003 Wiley Periodicals, Inc.
Team approaches to the development of innovative technologies and processes to facilitate remediation
Authors: Smith Terri
Published: June 2003

The enactment of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA)
created a complex liability scheme for owners, operators and prospective purchasers of contaminated properties,
particularly brownfields. As the program developed, liability issues related to contiguous property, prospective
purchasers, and no further action determinations became barriers to brownfield property redevelopment. The
national effort on the cleanup and redevelopment of brownfield sites took on new emphasis with the passing of
the federal “Small Business Liability Protection and Brownfields Revitalization Act” in January
2002. This new law provides liability clarifications as well as funding to facilitate the cleanup of brownfield
sites. President Bush stated in his 2003 State of the Union address, “In this century, the
greatest environmental progress will come about not through endless lawsuits or
command‐and‐control regulations, but through technology and innovation.” The
subject of this article is the Interstate Technology Regulatory Commission's Brownfield team, its current
initiative, goals, and areas of special focus. © 2003 Wiley Periodicals, Inc.
Looking for nuclear translation using xenopus oocytes
Authors: Cosson Bertrand , Philippe Michel
Published: June 2003

In eukaryotes transcription and translation takes place in two different compartments separated by the nuclear envelope. Nuclear translation has been reported in several publications, however, all these published results have been criticized, particularly with respect to cytoplasmic contamination of the nuclei. We have investigated the question of nuclear protein synthesis using a different strategy. We microinjected frog oocytes with different DNA and RNA constructs and searched for translation products in nuclei separated from the cytoplasm by microdissection. We have been unable to detect any translation within the nuclei but rather a saturable translation in the perinuclear cytoplasm associated with the isolated nuclei.
Momentum transfer between the Io plasma wake and Jupiter's ionosphere
Authors: Delamere P. A. , Bagenal F. , Ergun R. , Su Y.‐J.
Published: June 2003

The interaction between Io and Jupiter is dramatically illustrated by recent ultraviolet and infrared imaging of Jupiter's ionosphere. Bright auroral emissions are observed at the base of Io's flux tube with emissions at the footprint of Io's wake extending large distances downstream (roughly 100° around Jupiter). We propose as a possible explanation for the persisting wake emissions a subcorotating torus flux tube downstream from Io that results in high‐latitude parallel electric fields. The transfer of momentum to the subcorotating Iogenic plasma from first the corotating torus and eventually the Jovian ionosphere via the Alfvénic interaction result in intense field‐aligned currents which can lead to the formation of parallel electric fields. By comparing the field‐aligned current density of the initial Alfvénic disturbance generated by the stagnated flow in Io's wake to the required current density for steady state acceleration of the flux tube we infer a current limitation, or momentum decoupling, caused by a high‐latitude field‐aligned potential drop. As a result, the subcorotating flux tube is partially decoupled from the Jovian ionosphere and auroral emissions persist for large distances downstream of the initial Io‐disturbed flux tube. Model results suggest that the extended wake emissions are initially driven by a ∼70 kV cross‐wake potential, which is consistent with observed auroral emissions caused by electron precipitation with energy on the order of tens of keV.
The human telomere‐associated protein TIN2 stimulates interactions between telomeric DNA tracts in vitro
Authors: Kim Sahn‐Ho , Han Seungil , You Young‐Hyun , Chen David J , Campisi Judith
Published: June 2003

Human TIN2 interacts with the telomeric‐DNA‐binding protein TRF1, suppresses telomere elongation in telomerase‐positive cells, and may control telomere length by modulating telomere structure. To test the latter idea, we developed an in vitro assay, using biotinylated telomeric DNA probes and streptavidin–agarose, to quantify the ability of TRF1 and TIN2 to stimulate interactions of telomeric DNA tracts with each other (probe clustering). This assay revealed that TRF1 alone had weak probe‐clustering activity, but TIN2 stimulated activity fivefold to tenfold. A dominant‐negative TIN2 mutant protein that increased telomere length in vivo disrupted probe clusters formed by TRF1 and TIN2, suggesting that the ability to stimulate telomeric DNA interactions is important for telomere‐length regulation. Unlike TRF1, TIN2 did not form homodimers. We propose that TIN2 alters the conformation of TRF1, which favours a tertiary telomeric structure that hinders telomerase from gaining access to telomeres.
Extracorporeal photochemotherapy for paediatric patients with graft‐versus‐host disease after haematopoietic stem cell transplantation
Authors: Messina Chiara , Locatelli Franco , Lanino Edoardo , Uderzo Cornelio , Zacchello Graziella , Cesaro Simone , Pillon Marta , Perotti Cesare , Del Fante Claudia , Faraci Maura , Rivabella Lucia , Calore Elisabetta , De Stefano Pietro , Zecca Marco , Giorgiani Giovanna , Brugiolo Alessandra , Balduzzi Adriana , Dini Giorgio , Zanesco Luigi , Dall'Amico Roberto
Published: June 2003

Summary.This study aimed to ascertain whether extracorporeal photochemotherapy (ECP) is an effective treatment for paediatric patients with refractory graft‐versus‐host disease (GVHD). From January 1992 to December 2000, 77 children (median age 8·6 years) with either acute (n = 33) or chronic (n = 44) GVHD, resistant to conventional immunosuppressive therapy, were treated with ECP in four Italian paediatric hospitals. After ECP, acute GVHD involving skin, liver and gut responded completely in 76%, 60% and 75% of patients respectively. The 5‐year overall survival was 69% for responding patientsvs12% for non‐responders (P = 0·001). Among the 44 children with chronic GVHD, 15 (44%) showed a complete response and 10 (29%) a significant improvement after ECP. The 5‐year overall survival was 96% for respondersvs58% for non‐responders (P = 0·04). Our results suggest that ECP is an effective treatment that may be useful in paediatric patients with either acute or chronic GVHD who have failed to respond to standard immunosuppressive therapy.
Microbial causes of endodontic flare‐ups
Authors: Siqueira J. F.
Published: June 2003

Literature review  Inter‐appointment flare‐up is characterized by the development of pain, swelling or both, following endodontic intervention. The causative factors of flare‐ups encompass mechanical, chemical and/or microbial injury to the pulp or periradicular tissues. Of these factors, microorganisms are arguably the major causative agents of flare‐ups. Even though the host is usually unable to eliminate the root canal infection, mobilization and further concentration of defence components at the periradicular tissues impede spreading of infection, and a balance between microbial aggression and host defences is commonly achieved. There are some situations during endodontic therapy in which such a balance may be disrupted in favour of microbial aggression, and an acute periradicular inflammation can ensue. Situations include apical extrusion of infected debris, changes in the root canal microbiota and/or in environmental conditions caused by incomplete chemo‐mechanical preparation, secondary intraradicular infections and perhaps the increase in the oxidation–reduction potential within the root canal favouring the overgrowth of the facultative bacteria. Based on these situations, preventive measures against infective flare‐ups are proposed, including selection of instrumentation techniques that extrude lesser amounts of debris apically; completion of the chemo‐mechanical procedures in a single visit; use of an antimicrobial intracanal medicament between appointments in the treatment of infected cases; not leaving teeth open for drainage and maintenance of the aseptic chain throughout endodontic treatment. Knowledge about the microbial causes of flare‐ups and adoption of appropriate preventive measures can significantly reduce the incidence of this highly distressing and undesirable clinical phenomenon.
Prairie dog towns as islands: applications of island biogeography and landscape ecology for conserving nonvolant terrestrial vertebrates
Authors: Lomolino Mark V. , Smith Gregory A.
Published: June 2003

AimTo evaluate the utility of island biogeography theory as a model for understanding and conserving native communities of nonvolant terrestrial vertebrates at prairie dog towns.

LocationOklahoma Panhandle, USA.

MethodsWe surveyed mammal, reptile and amphibian communities on 36 black‐tailed prairie dog (Cynomys ludovicianus) towns during the summers and falls of 1997 to 1999. We used a Geographic Information System (GIS) to characterize the landscape within 10 km of each town. We used Principal Components Analysis (PCA), Correlation Analysis, and Linear Regression to test for patterns in species richness relative to area and isolation of towns, local habitat characteristics, and characteristics of the adjacent landscape.

ResultsSpecies richness was not significantly correlated with town size, town isolation, or local habitat characteristics. On the other hand, species richness was significantly correlated with characteristics of the landscape within 10 km of the focal town. In addition, species richness of mammals at prairie dog towns during the summer increased in a northerly direction, while richness of mammals at towns during fall increased to the west.

Main conclusionsThese results, albeit contrary to traditional island biogeography theory, are consistent with an emerging view that communities on relatively small islands are strongly influenced by characteristics of the adjacent landscape (or seascape). We recommend that to the extent possible, networks of reserves for prairie dogs and their associated species should include clusters of large towns (i.e. larger than those studied here), as well as large but isolated towns, and that conservation efforts should include management of the intervening matrix of anthropogenic habitats.
Iron Management in Hemodialysis Patients: Optimizing Outcomes in Vicenza, Italy
Authors: Crepaldi C. , Brendolan A. , Bordoni V. , Carta M. R. , D'Intini V. , Gastaldon F. , Inguaggiato P. , Ronco C.
Published: June 2003

The management of anemia in uremic patients undergoing hemodialysis requires the appropriate combination of erythropoietin treatment, iron supplementation, and on occasion androgen therapy.

Identifying and correcting functional iron deficiency is crucial to optimizing erythropoietin efficiency. Recently, however, the trend to administer maintenance iron with resultant high serum ferritin and high transferrin saturation has led to an increase in reports of iron overload.

Oral iron supplementation is inexpensive and safe, but poor patient compliance and reduced intestinal absorption may limit its efficacy. Intravenous iron, on the other hand, is effective, and its safety is related to the iron salt used. Currently available data suggest that iron saccharate may be the safest iron salt available for intravenous administration, although iron gluconate is safer than the dextran forms of intravenous iron. It should be kept in mind, however, that all forms of intravenous iron may have the potential of inducing iron overload.

At this time, the levels of ferritin that define iron overload are not clearly established. The side effects of iron overload are well recognized (infections, malignancies, vascular diseases); however, no guidelines exist for safe practice. There are many markers of iron deficiency, with serum ferritin and hypochromic red cell percentage currently the best markers available in clinical practice.
Increased local procoagulant action: a mechanism contributing to the favorable hemostatic effect of recombinant FVIIa in PLT disorders
Authors: Galán Ana‐María , Tonda Raúl , Pino Marcos , Reverter Juan Carlos , Ordinas Antonio , Escolar Ginés
Published: June 2003

BACKGROUND: Recombinant FVIIa (rFVIIa) has been shown to improve hemostasis in patients with thrombocytopenia and to prevent or control bleeding episodes in patients with inherited deficiencies of major PLT glycoproteins, but the mechanism of action is not well understood.

STUDY DESIGN AND METHODS: Effects of rFVIIa on hemostasis were explored with an in vitro perfusion technique. Blood samples, from healthy donors or from patients with congenital defects of PLT glycoprotein IIb–IIIa (GPIIb–IIIa), were anticoagulated with low‐molecular‐weight heparin. Experimental thrombocytopenia (<6000 PLTs/μL) was induced by a filtration procedure. rFVIIa was added to blood samples at therapeutic concentrations. A severe GPIIb–IIIa impairment was also induced by exposure of normal blood samples to a specific antibody. Perfusion studies were performed through annular chambers containing damaged vascular segments. The presence of fibrin and PLTs on the perfused subendothelium was morphometrically quantified.

RESULTS: Under conditions of experimental thrombocytopenia, addition of rFVIIa enhanced fibrin formation in a dose‐dependent manner (p < 0.05). Improvements in local fibrin generation and partial restoration of PLT interactions were also observed after incubation of blood from patients with Glanzmann's thrombasthenia with rFVIIa at 5 μg per mL (180 μg/kg). Similar improvements were observed in blood samples incubated with antibodies to GPIIb–IIIa. rFVIIa in whole normal blood also enhanced fibrin formation but PLT deposition was unaffected. Evaluation of prothrombin fragments 1 and 2 in the perfusates confirmed that rFVIIa increased thrombin generation in all cases.

CONCLUSION: Our data indicate that rFVIIa promotes a procoagulant activity at sites of vascular damage. This mechanism could explain the beneficial hemostatic effect of rFVIIa in patients with thrombocytopenia or with Glanzmann's thrombasthenia.
Magnetomechanical field computations of a clinical magnetic resonance imaging (MRI) scanner
Authors: Rausch M. , Gebhardt M. , Kaltenbacher M. , Landes H.
Published: June 2003

In this paper, an efficient magnetomechanical calculation scheme based on the finite element method is presented. This scheme is used for the precise forecast of the dynamical behavior of a clinical magnetic resonance imaging scanner. The validity of the computer simulations has been verified by means of appropriate measurements. Application examples include the optimization of the superconducting magnet regarding the eddy currents and vibrations in its cryostat.
Automating the design of low frequency electromagnetic devices – a sensitive issue
Authors: Lowther David A.
Published: June 2003

This paper discusses the possibility of automating the design of electromagnetic devices. Several paradigms currently exist to accelerate the design process, search the design space and examine the effects of tolerances on various parameters. Amongst these are semantic networks, response surfaces, interval mathematics and sensitivity analysis. This paper explores all of these and also suggests what is needed in the future in order to create a true computer based design system.
An electromagnetic approach to analyze the performance of the substation's grounding grid in high frequency domain
Authors: Zhang Bo , Cui Xiang , Zhao Zhibin , Yin Haoliu , Li Lin
Published: June 2003

According to the method of moment, an effective electromagnetic approach for the substation's grounding grid in high frequency domain is presented. An efficient method based on the generalized pencil‐of‐function method is developed to calculate the generalized Sommerfeld integral. With the method, the value of Green's function in a two‐layer medium can be obtained quickly and accurately. The number of unknown variables of the moment method is small. As the dipole antenna theory is introduced, the frequency of the injected current to the grounding grid can vary in a large scale. The method can be used to analyze not only the performance of the grounding grid, but also other grids located under the earth, in the air or penetrating a lossy interface. The computational results are in good agreement with those obtained by other method.
Psychosocial conditions on and off the job and psychological ill health: depressive symptoms, impaired psychological wellbeing, heavy consumption of alcohol
Authors: Michélsen H , Bildt C
Published: June 2003

Background:Psychiatric epidemiology has revealed a number of associations between gender, socioeconomic status, and psychiatric disorders.

Aims:To examine psychosocial conditions on and off the job in relation to psychological ill health.

Methods:Longitudinal design with 24 year follow up of employed persons (190 women, 177 men). Interview and questionnaire data on work and leisure conditions were collected in 1969 and 1993. Risk analyses were performed in relation to three outcomes in 1993: depression within the preceding 12 months, impaired psychological wellbeing, and heavy alcohol use.

Results:Thirteen per cent of the women and 11% of the men showed symptoms of depression, 21% and 22% had impaired psychological wellbeing, and 7% and 15% respectively were heavy alcohol users. Dissatisfaction with the quality (women) or quantity (men) of social contacts 24 years earlier was a significant risk factor for depression. Dissatisfaction with the quality of social contacts was also associated with impaired psychological wellbeing (among women), and dissatisfaction with leisure time activities was associated with heavy alcohol use (among men). Frequent overtime work 24 years earlier was associated with heavy alcohol use among women. Cross sectional analyses also showed associations between psychological ill health and some work related factors (mentally demanding work and lack of job pride).

Conclusions:Perceived inadequacies in social contacts, and practical obstacles to social relationships are viewed as risk factors for depression. In this longitudinal study, work related factors, including mental demands and time pressure, do not appear sufficiently associated with psychological ill health.
The Hubbard Model in the Two-Pole Approximation
Authors: Avella A. , Mancini F. , Villani D. , Siurakshina L. , Yushankhai V. Yu.
Published: June 2003

The two-dimensional Hubbard model is analyzed in the framework of the two-pole expansion. It is demonstrated that several theoretical approaches, when considered at their lowest level, are all equivalent and share the property of satisfying the conservation of the first four spectral momenta. It emerges that the various methods differ only in the way of fixing the internal parameters and that it exists a unique way to preserve simultaneously the Pauli principle and the particle–hole symmetry. A comprehensive comparison with respect to some general symmetry properties and the data from quantum Monte Carlo analysis shows the relevance of imposing the Pauli principle.
Equilibrium Nonlinear Distributions of One-Component Order Parameter in Systems with Competitive Interaction
Authors: Berezovsky S. V. , Klepikov V. F. , Korda V. Yu , Shlyakhov N. A.
Published: June 2003

The approach which enables to obtain the solutions of the variational equation as the series [Formula: see text] is considered. It is shown that when N=1 it gives well-known cos x solutions, while for N>1 it leads to essentially nonlinear functions. The φ2φ′2-term in the thermodynamical potential provides the proper nonlinear behavior of the order parameter and the possibility of existence of kink-like distributions, particularly. In special case N=2 there exist the exact partial solutions which, however, do not give the absolute minima to the thermodynamical potential.
A Simple Three-States Cellular Automaton for Modelling Excitable Media
Authors: Andrecut M.
Published: June 2003

Wave propagation in excitable media provides an important example of spatiotemporal self-organization. The Belousov–Zhabotinsky (BZ) reaction and the impulse propagation along nerve axons are two well-known examples of this phenomenon. Excitable media have been modelled by continuous partial differential equations and by discrete cellular automata. Here we describe a simple three-states cellular automaton model based on the properties of excitation and recovery that are essential to excitable media. Our model is able to reproduce the dynamics of patterns observed in excitable media.
Defects in Ferrites Studied by 57Fe NMR
Authors: Englich J. , Novák P. , Lütgemeier H.
Published: June 2003

Presence of defects in ferrites gives rise to a modification of the hyperfine field on nuclei of those iron ions, which are situated in the neighborhood of the defect. If the concentration of defects is small, satellite structure of the NMR spectra of 57 Fe nuclei is observed. Analysis of this satellite structure provides valuable information. In particular concentration of the defect, its distribution over various sublattices, magnetic moment and the valency may be obtained. In the present paper we describe how the analysis of the satellite structure is performed, summarize the requirements on the NMR experiment and illustrate the method using several examples of defects in the yttrium iron garnet.
Strongly Correlated Electron Systems: Spin-Reflection Positivity and Some Rigorous Results
Authors: Shen Shun-Qing
Published: June 2003

Theory of spin-reflection positivity developed in recent years is reviewed. This theory makes use of symmetries in an electron system and theory of matrix to investigate the ground state properties. Existences of anti- and ferromagnetic long-range orders in itinerant electron systems, and of off-diagonal long-range order are two successful applications of the theory. In this article, the author attempt to summarize exact results proved by utilizing this theory and related topics. First a general theory and basic theorems are introduced. Second, based on the band structures of conduction electrons, existences of a singlet state with strongly antiferromagnetic correlation, a state with both anti- and ferromagnetic long-range orders, and a fully saturated ferromagnetic state are proved. The theory is applied to several of the main theoretical models for strongly correlated electron systems, such as the Heisenberg model, the Hubbard model, the Anderson model, the single- and multichannel Kondo model, and the generalized Hubbard model, and a series of rigorous results are found in these models. Third, it is proved that off-diagonal long-range order and charge-density wave exist in the ground states of the attractive Hubbard model and the generalized Hubbard model. A relation between pseudospin symmetry and the uniform density theorem is introduced. Fourth, the theory is applied successfully to explain experimental observations of oscillatory interlayer magnetic coupling in ultrathin magnetic films. Finally several unsolved problems are discussed. All results introduced in this article are mathematically exact.