bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of medical polymer based on an epoxy resin system—Curing reaction characteristics of biphenol epoxy monomer with phenolic functional hardeners
Authors: Kim S. W. , Lu M. G. , Shim M. J.
Published: August 2002

The reaction kinetics of a biphenyl epoxy/polyol system was characterized by an isoconversional mode under dynamic conditions using differential scanning calorimetry (DSC) measurements. The results showed that the curing of epoxy resins involves different reaction stages and the values of activation energy is dependent on the degree of conversion. At the initial stage of cure, the phenol hydroxyl‐epoxy reaction is predominant, then the hydroxyl group generated during curing can catalyze the reaction. The results were supported by the isothermal experiments. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1495–1503, 2001
Studies on urethane‐modified alumina‐filled polyesteramide anticorrosive coatings cured at ambient temperature
Authors: Ahmad Sharif , Ashraf S. M. , Hasnat Abul , Yadav S. , Jamal A.
Published: August 2002

Coatings prepared from polyesteramide resin synthesized from linseed oil, a renewable resource, have been found to show improved physicomechanical and anticorrosive characteristics. These properties are further improved when aluminum is incorporated in the polyesteramide resin. The coatings of this resin are generally obtained by baking at elevated temperatures. With a view toward the use of linseed oil, as a precursor for the synthesis of polyesteramide resins and to cure their coatings at ambient temperature, toluylene diisocyanate (TDI) was incorporated into polyesteramide and alumina‐filled polyesteramide in varying proportions to obtain urethane‐modified resins. The latter resins were found to cure at room temperature. The broad structural features of the urethane‐modified polyesteramide and alumina‐filled polyesteramide were confirmed by FTIR and 1H–NMR spectroscopies. Scratch hardness; impact resistance; bending resistance; specular gloss; and resistance to acid, alkali, and organic solvents of the coatings of these resins were determined by standard methods. Physicomechanical and anticorrosive properties, specular gloss, and thermal stability of the urethane‐modified alumina‐filled polyesteramide coatings were found to be at higher levels among these resins. It was found that TDI could be incorporated in polyesteramide up to only 6 wt %, such that above this loading its properties started to deteriorate, whereas alumina‐filled polyesteramide could take up to 10 wt % TDI. Explanation is provided for the increase in scratch hardness and impact resistance above 6 and 10 wt % addition of TDI in polyesteramide and alumina‐filled polyesteramide, respectively, as well as for the decrease in flexibility and resistance to solvents, acid, and alkali of coatings of these resins above these limits of TDI addition. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1855–1865, 2001
Tensile properties of silkworm silk obtained by forced silking
Authors: Pérez‐Rigueiro J. , Elices M. , Llorca J. , Viney C.
Published: August 2002

Bave was acquired by the forced silking of three Bombyx mori silkworms, and its tensile properties were characterized. The material collected from any given silkworm yielded reproducible force‐displacement plots, which were qualitatively similar to the plots obtained from silk collected from the other silkworms. This uniformity contrasts with the highly variable properties exhibited by silk which had been reeled from degummed cocoons. Scanning electron microscopy images were used to obtain information about the sample cross‐sectional area, so that force‐displacement plots could be rescaled as stress–strain curves. Surprisingly, the scatter in the tensile properties increases after such rescaling. This finding can be explained in terms of the sericin coating of the bave (which contributes to the cross‐sectional area but not significantly to the load‐bearing capacity) having a variable thickness. When the sericin coating was eliminated by a degumming treatment, it was found that the fibers showed more consistent cross‐sectional areas. Therefore, stress–strain curves of forced B. mori silk are reproducible, provided that force‐displacement data are rescaled by the correct cross‐sectional area. Finally, the Weibull parameters of the forced silk were determined. The Weibull modulus, m, has a value of 13.0 ± 0.3, which is more than double the value obtained previously from silk reeled from a cocoon, demonstrating that the process of degumming cocoons has a detrimental effect on the distribution of defects in the silk microstructure. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1928–1935, 2001
Mechanical properties and superstructure of poly(ethylene terephthalate) fibers zone‐drawn and zone‐annealed by CO2 laser heating
Authors: Suzuki Akihiro , Mochiduki Noriaki
Published: August 2002

A laser‐heating zone‐drawing and zone‐annealing method using a continuous‐wave carbon dioxide laser was applied to poly(ethylene terephthalate) (PET) fiber to improve its mechanical properties. The as‐spun fiber was zone‐drawn under a applied tension (σa) of 4.44 MPa at a laser power density (PD) of 6.08 W cm−2, and then the laser‐heated zone‐drawn fiber was zone‐annealed. The laser‐heating zone‐annealing was carried out in three steps: the first annealing was carried out under σa = 139 MPa at 4.83 W cm−2; the second annealing was carried out under σa = 283 MPa at 4.83 W cm−2, and the third annealing was carried out under σa = 432 MPa at 3.45 W cm−2. The surface temperature distribution of the fiber irradiated with the CO2 laser was measured by using an infrared thermographic camera equipped with a magnifying lens. The relation between the laser power and the surface temperature of the fiber became clear in the laser‐heating zone‐drawing and the laser‐heating zone‐annealing. The fiber obtained finally had a birefringence of 0.239, a degree of crystallinity of 55%, a tensile modulus of 19.8 GPa, and a storage modulus of 25.7 GPa at 25°C. In FTIR measurements, a trans conformation increased with the processing, but a gauche one decreased. The laser‐heating zone‐drawing and zone‐annealing method was found to be effective in producing the PET fiber with high modulus and high strength. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2775–2783, 2001
Novel applications of lignin in composite materials
Authors: Thielemans W. , Can E. , Morye S. S. , Wool R. P.
Published: August 2002

Some exploratory work was done to look at novel applications, such as filler use and comonomers, for lignin in thermosetting unsaturated polyesters and vinyl esters. The solubility of different lignins (pine kraft, hardwood, ethoxylated, and maleinated) was determined in different resin systems (acrylated epoxidized soybean oil, hydroxylated soybean oil, soy oil monoglyceride, and a commercial vinyl ester) to give an idea of the compatibility of lignin with the resin systems that were used. Further, the use of lignin as a filler was studied. An increase in the glass‐transition temperature was noticed, and the modulus at 20°C decreased because of the plasticizing effect of lignin. The lignin was modified to improve its effect on the matrix properties by adding double bond functionality, thus making it possible to incorporate the lignin molecule in the resin through free‐radical polymerization. Modified lignin was introduced in several resins by a reaction with maleic anhydride and epoxidized soybean oil and was tested for its effect on the solubility, glass‐transition temperature, and modulus. This modification improved the solubility of lignin in styrene‐containing resins, as well as the chemical incorporation of lignin in the resin. Moreover, lignin was used to treat the surfaces of natural hemp fibers to utilize lignin's natural affinity for cellulosic fibers. The idea was to cure the surface defects on the natural fibers and increase the bonding strength between the resin and fiber. An optimum improvement was noticed that depended on the amount of lignin covering the fibers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 323–331, 2002
Interfacial adhesion reaction of polyethylene and starch blends using maleated polyethylene reactive compatibilizer
Authors: Yoo Seong Ik , Lee Tae Yeon , Yoon Jin‐San , Lee Ik‐Mo , Kim Mal‐Nam , Lee Han Sup
Published: August 2002

The interfacial reaction of the polyethylene (PE)/starch blend system containing the reactive compatibilizer maleated polyethylene (m‐PE) was directly characterized by Fourier transform infrared (FTIR) spectroscopy. A significant amount of anhydride groups on m‐PE existed as hydrolyzed forms, resulting in a large amount of carboxyl groups. Using a vacuum‐heating‐cell designed in the laboratory, the carboxyl groups were successfully transformed into the dehydrolyzed state (i.e., anhydride group). This result enabled the direct spectroscopic observation of chemical reaction occurring at the interface. For the PE/starch blend system containing m‐PE, the chemical reaction at the interface was verified by the evolution of ester and carboxyl groups in the FTIR spectra. The effect of the reactive compatibilizer on the interfacial morphology was also examined by scanning electron micrography (SEM). Enhanced interfacial adhesion was clearly observed for the blend system containing reactive compatibilizer. Tensile strengths of blend systems containing m‐PE also increased noticeably compared with the corresponding system without compatibilizer. A similar observation was made for the breaking elongation data. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 767–776, 2002
Mechanical properties and microstructure of HDPE/AL(OH)3/silicone oil composite
Authors: Yang Jinhai , Zhang Yong , Zhang Yinxi
Published: August 2002

The effect of surface modification on the mechanical properties and microstructure of the composites of high‐density polyethylene (HDPE), silicone oil, and aluminum hydroxide [Al(OH)3] was investigated. The dispersion of silicone oil in the HDPE composites was studied by scanning electric microscope (SEM) and differential scanning calorimetry (DSC). In the HDPE/Al(OH)3/silicone oil composites, two types of dispersion structure of silicone oil were observed resulting from different surface modifications. In the composites surface modified with titanate NDZ‐130, calcium stearate, or oleic acid, silicone oil encapsulates around Al(OH)3 particles, and both the notched impact strength and the elongation at break are very high. However, in the composites surface modified with silane KH‐550 or silane‐g‐HDPE, silicone oil and Al(OH)3 particles separately disperse in HDPE, and both the notched impact strength and the elongation at break are very low. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1896–1903, 2002
Issues for the conservation and management of Falkland Islands freshwater fishes
Authors: McDowall R.M. , Allibone R.M. , Chadderton W.L.
Published: August 2002

The Falkland Islands, in the cool‐temperate south‐western Atlantic Ocean, have an impoverished freshwater fish fauna, with only two indigenous species certainly present there: the Falklands minnow, Galaxias maculatus, and the zebra trout, Aplochiton zebra. Additional species whose presence there is uncertain are the southern pouched lamprey, Geotria australis, and the Patagonian puyen, Galaxias platei. Brown trout, Salmo trutta, were introduced in the mid‐20th century, and sea‐migratory (diadromous) populations are widespread.

Distributions of zebra trout and brown trout, particularly, are complementary, suggesting that brown trout are having detrimental impacts on zebra trout. Zebra trout have suffered massive decline over the past few decades and remain largely in restricted areas that brown trout have not yet invaded.

Owing to their sea‐migratory habits, it can be expected that brown trout will eventually invade all significant streams on the Falkland Islands. This raises issues of serious concern since zebra trout are also probably sea‐migratory, and therefore need access to and from the sea to complete their life cycles. Therefore, any streams accessible to zebra trout are potentially accessible also to brown trout, raising the spectre that eventually brown trout will invade all the streams where zebra trout persist.

The existence of landlocked populations of zebra trout provides some form of protection from brown trout invasion, though a landlocked stock does not represent the full behavioural and genetic diversity of zebra trout in Falkland's waters, and must be regarded as a last resort means for conservation.

Copyright © 2001 John Wiley & Sons, Ltd.
Daily morphological variations in the viscacha (Lagostomus maximus maximus) retina. Probable local modulatory action of melatonin
Authors: Calderón Claudia , Mohamed Fabian , Muñoz Estela , Fogal Teresa , Pelzer Lilian , Penissi Alicia , Piezzi Ramón
Published: August 2002

Given that the local melatonin levels exhibit rhythmic daily changes in the retina of the viscacha, we considered it important to study the likely daily variations in morphology and specific 2‐[125I]‐iodomelatonin binding in retinas from this rodent and to correlate these putative changes with local indole levels. Adult animals of both sexes were captured in their habitat and were kept under a natural photoperiod. For light and electron microscopic studies the viscachas were sacrificed by decapitation at 08:00, 16:00, and 24:00 hr. A computer‐assisted image analysis system was used to measure the thickness of the complete retina, the photoreceptor layer, the rod outer and inner segments, and the outer nuclear layer. The daily variation in 2‐[125I]‐iodomelatonin binding sites was followed during a 24‐hr light‐dark cycle, the animals being sacrificed at six time points. The parameters studied showed significant variations throughout the 24‐hr period. Maximal specific binding, lysosomal content in the pigment epithelium, and photoreceptor layer outer segment thicknesses were observed at 24:00 hr. Close contact between photoreceptor membranes and microvilli of the pigment epithelium was observed at 08:00 and 16:00 hr. Moreover, the minimal outer segment thickness at 16:00 hr was accompanied by a scarcity of dense bodies, such as lysosomes, a maximum dispersion of melanin pigment granules, and a minimum density of radioligand binding sites. Therefore, in the retina of the viscacha, we suggest that the interaction between melatonin and specific sites could be one of the factors or causes that participate in the regulation of the daily morphological changes observed in viscacha. Anat Rec 266:198–206, 2002. © 2002 Wiley‐Liss, Inc.
Three‐dimensional microimaging (MRμI and μCT), finite element modeling, and rapid prototyping provide unique insights into bone architecture in osteoporosis
Authors: Borah Babul , Gross Gary J. , Dufresne Thomas E. , Smith Tim S. , Cockman Michael D. , Chmielewski Paula A. , Lundy Mark W. , Hartke James R. , Sod Earl W.
Published: August 2002

With the proportion of elderly people increasing in many countries, osteoporosis has become a growing public health problem, with rising medical, social, and economic consequences. It is well recognized that a combination of low bone mass and the deterioration of the trabecular architecture underlies osteoporotic fractures. A comprehensive understanding of the relationships between bone mass, the three‐dimensional (3D) architecture of bone and bone function is fundamental to the study of new and existing therapies for osteoporosis. Detailed analysis of 3D trabecular architecture, using high‐resolution digital imaging techniques such as magnetic resonance microimaging (MRμI), micro‐computed tomography (μCT), and direct image analysis, has become feasible only recently. Rapid prototyping technology is used to replicate the complex trabecular architecture on a macroscopic scale for visual or biomechanical analysis. Further, a complete set of 3D image data provides a basis for finite element modeling (FEM) to predict mechanical properties. The goal of this paper is to describe how we can integrate three‐dimensional microimaging and image analysis techniques for quantitation of trabecular bone architecture, FEM for virtual biomechanics, and rapid prototyping for enhanced visualization. The integration of these techniques provide us with an unique ability to investigate the role of bone architecture in osteoporotic fractures and to support the development of new therapies. Anat Rec (New Anat) 265:101–110, 2001. © 2001 Wiley‐Liss, Inc.
Connections of the medial posterior parietal cortex (area 7m) in the monkey
Authors: Leichnetz George R.
Published: August 2002

The afferent and efferent cortical and subcortical connections of the medial posterior parietal cortex (area 7m) were studied in cebus (Cebus apella) and macaque (Macaca fascicularis) monkeys using the retrograde and anterograde capabilities of the horseradish peroxidase (HRP) technique. The principal intraparietal corticocortical connections of area 7m in both cebus and macaque cases were with the ipsilateral medial bank of the intraparietal sulcus (MIP) and adjacent superior parietal lobule (area 5), inferior parietal lobule (area 7a), lateral bank of the IPS (area 7ip), caudal parietal operculum (PGop), dorsal bank of the caudal superior temporal sulcus (visual area MST), and medial prestriate cortex (including visual area PO and caudalmedial lobule). Its principal frontal corticocortical connections were with the prefrontal cortex in the shoulder above the principal sulcus and the cortex in the shoulder above the superior ramus of the arcuate sulcus (SAS), the area purported to contain the smooth eye movement‐related frontal eye field (FEFsem) in the cebus monkey by other investigators. There were moderate connections with the cortex in the rostral bank of the arcuate sulcus (purported to contain the saccade‐related frontal eye field; FEFsac), supplementary eye field (SEF), and rostral dorsal premotor area (PMDr). Area 7m also had major connections with the cingulate cortex (area 23), particularly the ventral bank of the cingulate sulcus. The principal subcortical connections of area 7m were with the dorsal portion of the ventrolateral thalamic (VLc) nucleus, lateral posterior thalamic nucleus, lateral pulvinar, caudal mediodorsal thalamic nucleus and medial pulvinar, central lateral, central superior lateral, and central inferior intralaminar thalamic nuclei, dorsolateral caudate nucleus and putamen, middle region of the claustrum, nucleus of the diagonal band, zona incerta, pregeniculate nucleus, anterior and posterior pretectal nuclei, intermediate layer of the superior colliculus, nucleus of Darkschewitsch and dorsomedial parvicellular red nucleus (macaque cases only), dorsal, dorsolateral and lateral basilar pontine nuclei, nucleus reticularis tegmenti pontis, locus ceruleus, and superior central nucleus. The findings are discussed in terms of the possibility that area 7m contains a “medial parietal eye field” and belongs to a neural network of oculomotor‐related structures that plays a role in the control of eye movement. Anat Rec 263:215–236, 2001. © 2001 Wiley‐Liss, Inc.
Regaining chondrocyte phenotype in thermosensitive gel culture
Authors: An Yuehuei H. , Webb Darby , Gutowska Anna , Mironov Vladimir A. , Friedman Richard J.
Published: August 2002

Chondrocyte tissue engineering continues to be a challenging problem. When chondrocytes are duplicated in vitro, it is imperative to obtain an adequate number of cells of optimal phenotype. A temperature‐sensitive polymer gel, a copolymer of poly(N‐isopropylacrylamide) and acrylic acid (PNiPAAm‐co‐Aac), has the ability of gelling at 37°C (the lower critical solution temperature, LCST) or above and liquefying below that temperature (Vernon and Gutowska, Macromol. Symp. 1996;109:155–167). The hypothesis of this study was that chondrocytes could (1) duplicate in the copolymer gel; (2) regain their chondrocyte phenotype; and (3) be easily recovered from the gel by simply lowering the temperature below 37°C. Chondrocytes from adult rabbit scapular cartilage were harvested and cultured in a monolayer culture until confluency (approximately 2 weeks). Next, the cells were harvested and seeded into the copolymer gel and cultured for 2–4 weeks. The phenotype of the cultured cells was then characterized. Two groups of control cultures, monolayer and agarose gel, were used to compare their ability to maintain chondrocyte phenotype. The results showed that chondrocytes isolated from rabbit scapula can re‐express chondrocyte phenotype in agarose culture and polymer gel culture but not in monolayer culture. Also, cultured chondrocytes can be easily recovered from polymer gel culture by simply lowering the temperature. This new in vitro method of chondrocyte culture is recommended for chondrocyte propagation and regaining chondrocyte phenotype before cell seeding or transplantation. Anat Rec 263:336–341, 2001. © 2001 Wiley‐Liss, Inc.
Septation and valvar formation in the outflow tract of the embryonic chick heart
Authors: Qayyum Sonia R. , Webb Sandra , Anderson Robert H. , Verbeek Fons J. , Brown Nigel A. , Richardson Michael K.
Published: August 2002

There is no agreement, in the chick, about the number of the endocardial cushions within the outflow tract or their pattern of fusion. Also, little is known of their relative contributions to the formation of the arterial valves, the subpulmonary infundibulum, and the arterial valvar sinuses. As the chick heart is an important model for studying septation of the outflow tract, our objective was to clarify these issues. Normal septation of the outflow tract was studied in a series of 60 staged chick hearts, by using stained whole‐mount preparations, serial sections, and scanning electron microscopy. A further six hearts were examined subsequent to hatching. At stage 21, two pairs of endocardial cushions were seen within the developing outflow tract. One pair was positioned proximally, with the other pair located distally. By stage 25, a third distal cushion had developed. This finding was before the appearance of two further, intercalated, endocardial cushions, also distally positioned, which were first seen at stage 29. In the arterial segment, the aortic and pulmonary channels were separated by the structure known as the aortopulmonary septum. The dorsal limb of this septum penetrated the distal dorsal cushion, whereas the ventral limb grew between the remaining two distal cushions, both of which were positioned ventrally. The three distal endocardial cushions, and the two intercalated endocardial cushions, contributed to the formation of the leaflets and sinuses of the arterial roots. The two proximal cushions gave rise to a transient septum, which later became transformed into the muscular component of the subpulmonary infundibulum. Concomitant with these changes, an extracardiac tissue plane was formed which separated this newly formed structure from the sinuses of the aortic root. Our study confirms that three endocardial cushions are positioned distally, and two proximally, within the developing outflow tract of the chick. The pattern of the distal cushions, and the position of the ventral limb of the aortopulmonary septum, differs significantly from that seen in mammals. Anat Rec 264:273–283, 2001. © 2001 Wiley‐Liss, Inc.
Glutathione S‐transferase isoenzymes in the two‐spot ladybird, Adalia bipunctata (Coleoptera: Coccinellidae)
Authors: Francis Frédéric , Haubruge Eric , Dierickx Paul
Published: August 2002

Isoenzymes of glutathione S‐transferase (GST) in adult Adalia bipunctata, an aphidophagous predator, were studied. Cytosolic GST activity was studied in each beetle developmental stage. The highest activities towards both 1‐chloro‐2,4‐dinitrobenzene (CDNB) and 2,4‐dinitro‐1‐iodobenzene (DNIB) occurred in adults. The enzyme distribution was investigated in adults. While most of the enzymatic activity was found in the abdomen (40–50 and 34–63% respectively) using several concentrations of both CDNB and DNIB, significant differences were observed for the head and the thorax depending on the substrate. Activities were more abundant in the thorax with DNIB (37–47%) compared to the 13–19% obtained with CDNB. Some GST activity was also detected in the elytra. GSTs were purified by epoxy‐activated Sepharose 6B affinity chromatography and applied to an HPLC column to determine the native molecular weight (69 kDa). Three isoenzymes were separated by chromatofocusing at pH ranges 7–4. Three bands with molecular mass from 23 to 26 kDa were visualised on SDS‐PAGE. Their isoelectric points were 6.66, 6.36, and 6.21. The substrate specificities and the kinetic parameters (Vm and Km) of the isoenzymes showed large differences depending on the isoenzyme. Arch. Insect Biochem. Physiol. 49:158–166, 2002. © 2002 Wiley‐Liss, Inc.
Gonadotropins in insects: An overview
Authors: De Loof Arnold , Baggerman Geert , Breuer Michael , Claeys Ilse , Cerstiaens Anja , Clynen Elke , Janssen Tom , Schoofs Liliane , Vanden Broeck Jozef
Published: August 2002

Control of gonad development in insects requires juvenile hormone, ecdysteroids, and a peptidic brain gonadotropin(s). Compared to vertebrates, the situation in insects with respect to the molecular structure of gonadotropins is far less uniform. Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) of vertebrates are glycoproteins that are synthezised in the hypothalamus and released from the anterior pituitary. They stimulate gonad development, the production of progesterone or of sex steroids (estrogens, androgens). None of the known insect gonadotropins is a glycoprotein, neither can they be grouped into a single peptide family. In Drosophila, two G‐protein coupled receptors, structurally related to the mammalian glycoprotein hormone receptors, have been identified. Nothing is known about their natural ligands. The sex‐steroids of insects are likely to be ecdysteroids (20E in females, E in males of some species). Some of the identified gonadotropins speed up vitellogenesis (locust OMP and some ‐PF/‐RFamide peptides) or stimulate ecdysteroid production by the ovaries (locust‐OMP and Aedes‐ OEH) or testis (testis ecdysiotropin of Lymantria). In flies, the only as yet identified gonadotropin is the cAMP‐generating peptide of Neobellieria. The seeming absence of uniformity in gonadotropins in insects might be due to a multitude of factors that can stimulate ecdysteroid production and/or to the use of different bioassays. Arch. Insect Biochem. Physiol. 47:129–138, 2001. © 2001 Wiley‐Liss, Inc.
How to diagnose rheumatoid arthritis early: A prediction model for persistent (erosive) arthritis
Authors: Visser Henk , le Cessie Saskia , Vos Koen , Breedveld Ferdinand C. , Hazes Johanna M. W.
Published: August 2002

Objective

To develop a clinical model for the prediction, at the first visit, of 3 forms of arthritis outcome: self‐limiting, persistent nonerosive, and persistent erosive arthritis.

Methods

A standardized diagnostic evaluation was performed on 524 consecutive, newly referred patients with early arthritis. Potentially diagnostic determinants obtained at the first visit from the patient's history, physical examination, and blood and imaging testing were entered in a logistic regression analysis. Arthritis outcome was recorded at 2 years' followup. The discriminative ability of the model was expressed as a receiver operating characteristic (ROC) area under the curve (AUC).

Results

The developed prediction model consisted of 7 variables: symptom duration at first visit, morning stiffness for ≥1 hour, arthritis in ≥3 joints, bilateral compression pain in the metatarsophalangeal joints, rheumatoid factor positivity, anti–cyclic citrullinated peptide antibody positivity, and the presence of erosions (hands/feet). Application of the model to an individual patient resulted in 3 clinically relevant predictive values: one for self‐limiting arthritis, one for persistent nonerosive arthritis, and one for persistent erosive arthritis. The ROC AUC of the model was 0.84 (SE 0.02) for discrimination between self‐limiting and persistent arthritis, and 0.91 (SE 0.02) for discrimination between persistent nonerosive and persistent erosive arthritis, whereas the discriminative ability of the American College of Rheumatology 1987 classification criteria for rheumatoid arthritis was significantly lower, with ROC AUC values of 0.78 (SE 0.02) and 0.79 (SE 0.03), respectively.

Conclusion

A clinical prediction model was developed with an excellent ability to discriminate, at the first visit, between 3 forms of arthritis outcome. Validation in other early arthritis clinics is necessary.
The influence of patient characteristics, disease variables, and HLA alleles on the development of radiographically evident sacroiliitis in juvenile idiopathic arthritis
Authors: Flatø Berit , Smerdel Anna , Johnston Virginia , Lien Gunhild , Dale Knut , Vinje Odd , Egeland Thore , Sørskaar Dag , Førre Øystein
Published: August 2002

Objective

To assess the frequency of sacroiliitis and the radiographic and clinical outcome in juvenile idiopathic arthritis (JIA) and determine patient characteristics, early disease variables, and genetic markers that predict development of sacroiliitis.

Methods

We performed a retrospective cohort study of 314 (79%) of the 400 JIA patients first admitted to the hospital between 1980 and 1985. The participants were examined after a median disease duration of 14.9 years (range 11.7–25.1). Radiographs of the sacroiliac joints, hips, ankles, and tarsi were obtained and studied in a blinded manner by 2 radiologists. The presence of HLA–DRB1 and DPB1 alleles was determined by genotyping and that of HLA–B27 by serologic testing. Variables relating to the onset and course of the disease were obtained by chart reviews.

Results

Twenty (6%) of the JIA patients developed radiographic sacroiliitis according to the New York criteria. In 9 patients (45%), sacroiliitis had not been demonstrated before the followup examination. At followup, spinal flexion (lateral and anterior) was reduced in 70–75% of patients with sacroiliitis and in 30–35% of those without sacroiliitis. Compared with the JIA patients without sacroiliitis, those with sacroiliitis more frequently had inflammatory back pain, enthesitis, radiographic changes in the hips and calcanei, erosions of any peripheral joint, and uveitis.

Predictors of sacroiliitis were HLA–B27, absence of DPB1*02, hip joint involvement within the first 6 months, and disease onset after age 8 years. The following factors were more common among patients in whom sacroiliitis developed than in other JIA patients: DRB1*04, male sex, family history of ankylosing spondylitis, psoriasis, inflammatory back pain, and enthesitis within the first 6 months.

Conclusion

In the current study, radiographically evident sacroiliitis had developed in 6% of JIA patients after a median disease duration of 14.9 years. HLA–B27, absence of DPB1*02, late onset of disease, and early hip involvement were predictors of sacroiliitis.
Early and aggressive treatment of rheumatoid arthritis patients affects the association of HLA class II antigens with progression of joint damage
Authors: Lard L. R. , Boers M. , Verhoeven A. , Vos K. , Visser H. , Hazes J. M. W. , Zwinderman A. H. , Schreuder G. M. T. , Breedveld F. C. , De Vries R. R. P. , Van Der Linden S. , Zanelli E. , Huizinga T. W. J.
Published: August 2002

Objective

The presence of certain HLA class II antigens is strongly associated with the progression of joint destruction in rheumatoid arthritis (RA). Such antigens may be more effective than other class II antigens in inducing the formation of autoreactive T cells after presentation of (auto)antigens. We investigated whether early and aggressive treatment with disease‐modifying antirheumatic drugs could modify this relationship.

Methods

We analyzed data from 2 studies of patients with early RA treated according to different strategies. The first study consisted of 2 cohorts, one (n = 109; median disease duration before treatment 4 months) was treated according to the pyramid strategy (initial nonsteroidal antiinflammatory drugs, followed by chloroquine [CQ] or sulfasalazine [SSZ] when necessary), and the other (n = 97; median disease duration before treatment 2 weeks) was immediately treated with CQ or SSZ. The second study comprised 155 patients (median disease duration 4 months) from the Combinatietherapie Bij Reumatoide Artritis (COBRA) trial, in which patients were randomly assigned to combination treatment with step‐down prednisolone, methotrexate (MTX), and SSZ (n = 76) or with SSZ alone (n = 79). Prednisolone and MTX dosages were tapered and stopped after 28 and 40 weeks, respectively. The extent of joint damage was measured by the modified Sharp method.

Results

In the pyramid treatment cohort, the median increase in Sharp score after 2 years was 12 in patients positive for the shared epitope (SE) and 1 in SE− patients. In the immediate treatment cohort, the median increase was 3 in SE+ patients and 2 in SE− patients. In the SSZ group of the COBRA study, the median increase in Sharp score after 1 year was 11 in DR4+ patients and 3 in DR4− patients. In the combination treatment group, the median increase was 4 in DR4+ patients and 2 in DR4− patients. Significance was confirmed by multiple regression using log‐transformed scores.

Conclusion

Early and aggressive antirheumatic drug treatment affects the association of HLA class II alleles with progression of joint damage in RA.
Reshaping the shared epitope hypothesis: HLA‐associated risk for rheumatoid arthritis is encoded by amino acid substitutions at positions 67–74 of the HLA–DRB1 molecule
Authors: de Vries Niek , Tijssen Henk , van Riel Piet L. C. M. , van de Putte Leo B. A.
Published: August 2002

Objective

To further analyze the association of HLA–DRB1 alleles with disease susceptibility in recent‐onset rheumatoid arthritis (RA).

Methods

One hundred sixty‐seven Caucasian RA patients and 166 healthy controls were typed for HLA–DRB1.

Results

The association of susceptibility to RA with the group of alleles encoding the shared epitope susceptibility sequences (SESSs) was confirmed in recent‐onset RA. Among non‐SESS alleles, DRB1*07, *1201, *1301, and *1501 showed significant protective effects. Even after correction for the influence of SESS alleles, significant independent protective effects of DRB1 alleles were observed. Protective alleles shared a third hypervariable region motif. Independent homozygosity effects were observed both for susceptibility and for protective alleles.

Conclusion

Nonsusceptibility alleles differ significantly with regard to RA risk. Protective alleles show clear homology at positions 67–74, often encoding isoleucine at position 67 or aspartic acid at position 70. Susceptibility and protective alleles both show homozygosity effects. Based on these results and on data reported in the literature, in order to incorporate the finding of differential risks among nonsusceptibility alleles, we propose to reshape the shared epitope hypothesis as follows: HLA‐associated risk for RA is encoded by amino acid substitutions at positions 67–74 of the HLA–DRB1 molecule.
The modulation of matrix metalloproteinase and ADAM gene expression in human chondrocytes by interleukin‐1 and oncostatin M: A time‐course study using real‐time quantitative reverse transcription–polymerase chain reaction
Authors: Koshy P. J. T. , Lundy C. J. , Rowan A. D. , Porter S. , Edwards D. R. , Hogan A. , Clark I. M. , Cawston T. E.
Published: August 2002

Objective

Previous studies have reported elevated levels of interleukin‐1 (IL‐1) and oncostatin M (OSM) in rheumatoid joints, as well as the synergistic degradation of human articular cartilage by this cytokine combination. The present study was undertaken to investigate the ability of IL‐1 and OSM to modulate gene expression of matrix metalloproteinase (MMP), ADAM, and ADAM‐TS (ADAM with thrombospondin motifs) family members in human chondrocytes.

Methods

T/C28a4 human chondrocytes were stimulated for 2–48 hours with IL‐1 and/or OSM. Total RNA was harvested, reverse transcribed, and assessed by real‐time polymerase chain reaction for the expression of various MMP, ADAM, and ADAM‐TS messenger RNAs (mRNA). Results were normalized to 18S ribosomal RNA.

Results

IL‐1 and OSM synergized to markedly induce the expression of the collagenases MMP‐1, MMP‐8, and MMP‐13 as well as MMP‐3, an activator of proMMPs. Expression of mRNA for MMPs 1, 3, and 13 was induced early, whereas that of MMP‐8 mRNA occurred late. Gene expression of MMP‐14, an MMP that degrades collagen and activates proMMP‐13, was elevated by this combination. IL‐1 and OSM also synergized to induce gene expression of the aggrecanase ADAM‐TS4, but not ADAM‐TS5.

Conclusion

These data indicate that the potent cartilage‐degrading properties of the combination of IL‐1 and OSM are potentially mediated by a synergistic induction of the aggrecan‐degrading enzyme ADAM‐TS4 and the collagen‐degrading enzymes MMP‐1, MMP‐8, MMP‐13, and MMP‐14, although differences in the magnitude of response and in the time course of induction were observed. A role for MMPs 3 and 14 in the activation of proMMPs may also be implicated.
Decreased aerobic capacity in children with juvenile dermatomyositis
Authors: Hicks Jeanne E. , Drinkard Bart , Summers Ronald M. , Rider Lisa G.
Published: August 2002

Objective

To determine whether patients with juvenile dermatomyositis (DM) have limited aerobic capacity compared with healthy controls.

Methods

Fourteen juvenile DM patients with inactive to moderately active, stable disease (age range 7–17 years) and 14 age‐ and sex‐matched controls performed a maximal exercise test using a cycle ergometer. Oxygen uptake and power were measured at peak exercise (VO2peak and Wpeak, respectively) and at anaerobic threshold (AT and WAT). Juvenile DM disease activity and damage were also assessed.

Results

Patients with juvenile DM had significantly reduced VO2peak (19.6 ml O2/kg/minute in juvenile DM versus 31.1 ml O2/kg/minute in controls), peak heart rate (166 versus 184 beats per minute), Wpeak (1.6 versus 2.7 watts/kg), AT (11.1 versus 18.0 ml O2/kg/minute) and WAT (0.6 versus 1.4 watts/kg), compared to controls (P ≤ 0.05 for each). Aerobic exercise parameters correlated with physician global disease activity and damage, T1‐weighted magnetic resonance imaging, and Childhood Myositis Assessment Scale scores (rs = 0.58 − 0.82, P ≤ 0.05).

Conclusion

Patients with juvenile DM with a range of disease activity have a decreased aerobic and work capacity compared to healthy children. Aerobic exercise limitation in juvenile DM correlates best with measures of disease damage (global damage assessment, T1‐weighted magnetic resonance imaging, and disease duration). Aerobic exercise testing may be valuable in the assessment of physical endurance, and aerobic training may be indicated as part of the therapeutic regimen in myositis patients with inactive to moderately active, stable disease.
Querying and ranking XML documents
Authors: Schlieder Torsten , Meuss Holger
Published: August 2002

XML represents both content and structure of documents. Taking advantage of the document structure promises to greatly improve the retrieval precision. In this article, we present a retrieval technique that adopts the similarity measure of the vector space model, incorporates the document structure, and supports structured queries. Our query model is based on tree matching as a simple and elegant means to formulate queries without knowing the exact structure of the data. Using this query model we propose a logical document concept by deciding on the document boundaries at query time. We combine structured queries and term‐based ranking by extending the term concept to structural terms that include substructures of queries and documents. The notions of term frequency and inverse document frequency are adapted to logical documents and structural terms. We introduce an efficient technique to calculate all necessary term frequencies and inverse document frequencies at query time. By adjusting parameters of the retrieval process we are able to model two contrary approaches: the classical vector space model, and the original tree matching approach.
Research in image indexing and retrieval as reflected in the literature
Authors: Chu Heting
Published: August 2002

Documents relevant to the subject of image indexing and retrieval, obtained from the SCI and SSCI databases, were examined and analyzed. The study confirms that there exist in this rapidly growing field two distinctive research groups employing the content‐based and description‐based approaches, respectively. However, research in the content‐based domain is currently dominating in the field, while the other approach has less visibility. Although researchers using the content‐based approach actively communicated with colleagues from the same group, collaboration between the different clusters of scientists should be further promoted and encouraged to advance research and development in image indexing and retrieval.
Effects of link annotations on search performance in layered and unlayered hierarchically organized information spaces
Authors: Fraser Landon , Locatis Craig
Published: August 2002

The effects of link annotations on user search performance in hypertext environments having deep (layered) and shallow link structures were investigated in this study. Four environments were tested—layered‐annotated, layered‐unannotated, shallow‐annotated, and shallow‐unannotated. A single document was divided into 48 sections, and layered and unlayered versions were created. Additional versions were created by adding annotations to the links in the layered and unlayered versions. Subjects were given three queries of varying difficulty and then asked to find the answers to the queries that were contained within the hypertext environment to which they were randomly assigned. Correspondence between the wording links and queries was used to define difficulty level. The results of the study confirmed previous research that shallow link structures are better than deep (layered) link structures. Annotations had virtually no effect on the search performance of the subjects. The subjects performed similarly in the annotated and unannotated environments, regardless of whether the link structures were shallow or deep. An analysis of question difficulty suggests that the wording in links has primacy over the wording in annotations in influencing user search behavior.
Distribution of ifosfamide and metabolites between plasma and erythrocytes
Authors: Kerbusch T. , Herben V.M.M. , Jeuken M‐J.J. , Ouwerkerk J. , Keizer H.J. , Beijnen J.H.
Published: August 2002

The distribution of ifosfamide (IF) and its metabolites 2‐dechloroethylifosfamide (2DCE), 3‐dechloroethylifosfamide (3DCE), 4‐hydroxyifosfamide (4OHIF) and ifosforamide mustard (IFM) between plasma and erythrocytes was examined in vitro and in vivo. In vitro distribution was investigated by incubating blood with various concentrations of IF and its metabolites. In vivo distribution of IF, 2DCE, 3DCE and 4OHIF was determined in 7 patients receiving 9 g/m2/72 h intravenous continuous IF infusion. In vitro distribution equilibrium between erythrocytes and plasma was obtained quickly after drug addition. Mean (±sem) in vitro and in vivo erythrocyte (e)–plasma (p) partition coefficients (Pe/p) were 0.75±0.01 and 0.81±0.03, 0.62±0.09 and 0.73±0.05, 0.76±0.10 and 0.93±0.05 and 1.38±0.04 and 0.98±0.09 for IF, 2DCE, 3DCE and 4OHIF, respectively. These ratios were independent of concentration and unaltered with time. The ratios of the area under the erythrocyte and plasma concentration‐‐time curves (AUCe/p) were 0.96±0.03, 0.87±0.07, 0.98±0.06 and 1.34±0.39, respectively. A time‐ and concentration‐dependent distribution‐‐equilibrium phenomenon was observed with the relative hydrophilic IFM. It is concluded that IF and metabolites rapidly reach distribution equilibrium between erythrocytes and plasma; the process is slower for IFM. Drug distribution to the erythrocyte fraction ranged from about 38% for 2DCE to 58% for 4OHIF, and was stable over a wide range of clinically relevant concentrations. A strong parallelism in the erythrocyte and plasma concentration profiles was observed for all compounds. Thus, pharmacokinetic assessment using only plasma sampling yields direct and accurate insights into the whole blood kinetics of IF and metabolites and may be used for pharmacokinetic–pharmacodynamic studies. Copyright © 2001 John Wiley & Sons, Ltd.
Cytological effects of 60 Hz magnetic fields on human lymphocytes in vitro: sister‐chromatid exchanges, cell kinetics and mitotic rate
Authors: Heredia–Rojas J. Antonio , Rodríguez‐De la Fuente Abraham O. , del Roble Velazco‐Campos M. , Leal‐Garza Carlos H. , Rodríguez‐Flores Laura E. , de la Fuente‐Cortez Beatriz
Published: August 2002

Incubation for 72 h of human peripheral blood cultures in the presence of 60 Hz sinusoidal magnetic fields (MF) at magnetic flux densities of 1.0, 1.5, and 2.0 mT led to stimulation of lymphocyte proliferation but had no influence on the frequency of sister‐chromatid exchanges (SCE). The cytotoxic potential of MF combined with the mutagen Mitomycin‐C also was analyzed. An opposite effect between MF exposure and Mitomycin‐C treatment in terms of cell kinetics and mitotic rate was found, whereas no variation in SCE frequency was observed for this coexposure condition. Bioelectromagnetics 22:145–149, 2001. © 2001 Wiley‐Liss, Inc.
Long‐term effects of 60‐Hz electric vs. magnetic fields on IL‐1 and IL‐2 activity in sheep
Authors: Hefeneider Steven H. , McCoy Sharon L. , Hausman Frances A. , Christensen Heidi L. , Takahashi Diana , Perrin Nancy , Bracken T. Dan , Shin K.Y. , Hall Arthur S.
Published: August 2002

This study was designed to assess the effect of exposure to long‐term extremely low‐frequency electric and magnetic fields (ELF–EMF) from a 500 kV transmission line on IL‐1 and IL‐2 activity in sheep. The primary hypothesis was that the reduction in IL‐1 activity observed in our two previous short‐term studies (10 months) was due to EMF exposure from this transmission line. To repeat and expand these studies and to characterize the components of EMF responsible for the previously observed reduction in IL‐1 activity, the current experiment examined not only the effect of exposure to electric and magnetic fields, but also the magnetic field component alone. In the current study, IL‐2 was examined to characterize the effects of EMF exposure on an indicator of T cell responses. 45 Suffolk ewe lambs were randomized into three groups of 15 animals each. One group of animals was placed in the EMF pen, located directly beneath the transmission line. A second group was placed in the shielded MF (magnetic field only) pen, also directly beneath the transmission line. The third group of animals was placed in the control pen located several hundred meters away from the transmission line. During the 27 month exposure period, blood samples were taken from all animals monthly. When the data were analyzed collectively over time, no significant differences between the groups were found for IL‐1 or IL‐2 activity. In previous studies ewe lambs of 8–10 weeks of age were used as the study animals and significant differences in IL‐1 activity were observed after exposure of these animals to EMF at mean magnetic fields of 3.5–3.8 μT (35–38 mG) and mean electric fields of 5.2–5.8 kV/m. At the start of the current study EMF levels were reduced as compared to previous studies. One interpretation of the current data is that magnetic field strength and age of the animals may be important variables in determining whether EMF exposure will affect IL‐1 activity. Bioelectromagnetics 22:170–177, 2001. © 2001 Wiley‐Liss, Inc.