bluuebunny/crossref_metadata_2025 huggingface dataset:
Review: Biological effects of organic arsenic compounds in seafood
Authors: Sakurai Teruaki
Published: September 2002

This review describes the results of our recent experiments concerning the in vitro biological effects of water‐soluble organic arsenic compounds contained in seafood in murine immune effector cells using synthetic pure materials. A dimethyl organic arsenic compound in seaweed, viz. an arsenosugar, was weakly cytotoxic in murine alveolar macrophages during a 72 h incubation (50% lethal concentration in vitro, LC50 = 8 mmol dm−3); conversely, it increased the cell viability of peritoneal macrophages at an optimal dose of 5 mmol dm−3. Trimethyl arsenic compounds in marine animals, arsenocholine and arsenobetaine, were less toxic in murine splenocytes, thymocytes, Peyer's patch lymphocytes, peritoneal macrophages and alveolar macrophages in vitro, even over 10 mmol dm−3. Interestingly, they significantly increased the cell viability of immature bone marrow cells at doses over 100 µmol dm−3, and induced the maturation of bone marrow cells especially into granulocytes. The tetramethyl arsenic compound, tetramethylarsonium hydroxide, isolated from some lower marine animals had no in vitro cytolethality on murine immune effector cells. Taken together, organic arsenic compounds in seafood are not very toxic in living systems. Copyright © 2002 John Wiley & Sons, Ltd.
Cytotoxicological aspects of the organic arsenic compound arsenobetaine in marine animals
Authors: Kojima Chikara , Sakurai Teruaki , Ochiai Masayuki , Kumata Hidetoshi , Qu Wei , Waalkes Michael P. , Fujiwara Kitao
Published: September 2002

In this study, we investigated the in vitro cytotoxicity of arsenobetaine [AsBe; trimethyl (carboxymethyl) arsonium zwitterion], which is a major organic arsenic compound in marine animals, to various mammalian cells, such as mouse macrophage RAW264.7 cells, rat liver TRL1215 cells and human skin TIG‐112 cells, using a synthetic pure material. As a result, we demonstrated that the cytotoxicity of AsBe is very weak even at concentrations over 20 mmol dm−3 in all these cells. Also, AsBe did not affect various functions of the murine macrophage RAW264.7 cells, viz interleukin‐1α production, cellular lysosomal enzyme (acid phosphatase) activity and nitric oxide (NO2−) secretion. AsBe showed a weak effect on the reduced glutathione (GSH) levels in these cells, and it slightly reduced the cellular GSH levels for a while. These data suggest that AsBe shows no cytotoxicity but has some effects on mammalian cells. Copyright © 2002 John Wiley & Sons, Ltd.
Studies on thermal and morphological behavior of siliconized epoxy bismaleimide matrices
Authors: Kumar A. Ashok , Alagar M. , Rao R. M. V. G. K.
Published: September 2002

Novel bismaleimide‐modified siliconized epoxy intercrosslinked network systems were developed. Siliconized epoxy systems containing 5, 10, and 15% siloxane units were prepared using epoxy resin and hydroxyl‐terminated polydimethylsiloxane (HTPDMS) with γ‐aminopropyltriethoxysilane (γ‐APS) as a compatibilizer and dibutyltindilaurate as a catalyst. The siliconized epoxy systems were further modified with 5, 10, and 15% (wt %) of bismaleimide [(N,N′‐bismaleimido‐4,4′‐diphenylmethane) (BMI)] and cured by diaminodiphenylmethane (DDM). Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and heat‐distortion temperature measurement of the matrix samples were carried out to assess their thermal behavior. DSC thermograms of the BMI‐modified epoxy systems show unimodel reaction exotherms. The glass transition temperature (Tg) of the cured BMI‐modified epoxy and siliconized epoxy systems increases with increasing BMI content. Thermogravimetric analysis and heat‐distortion temperature measurements indicate that the thermal degradation temperature and heat‐distortion temperature of the BMI‐modified epoxy and siliconized epoxy systems increase with increasing BMI content. The morphology of the BMI‐modified siliconized epoxy systems was also studied by scanning electron microscopy (SEM). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2330–2346, 2001
Application of dimer acid–based polyamide for xerographic toners for textiles printing
Authors: Carr W. W. , Cook F. L. , Yan H. , Pfromm P. H.
Published: September 2002

Xerographic printing of textiles was explored. A number of fabrics were printed using commercially available and synthesized polymers as toner vehicles. The polymers were characterized using standard methods (DSC, DMA, tensile tests). The performance of the prints was evaluated using textiles‐specific tests (crockfastness, flexural rigidity). It was found that the initial modulus is a reasonable predictor of the performance of the printed fabrics. However, the requirements on toner vehicles for good textile performance (low initial modulus, flexibility) contradict the requirements for production of toner powders by grinding (brittle behavior). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2399–2407, 2001
Spectrophotometric investigation of the copolymerization of styrene or methyl methacrylate with 1,8‐naphthalimide dyes
Authors: Grabchev Ivo , Bojinov Vladimir , Betcheva Rossiza
Published: September 2002

The copolymerization of styrene or methyl methacrylate with 1,8‐naphthalimide dyes to yield fluorescent side‐group copolymers was investigated. During copolymerization, no changes occurred in the chromophoric systems of the dyes. Colorimetrically, it was found that more that 0.90% of the dyes were chemically bonded to the polymer chain. The effect of polymer coloration was proven by appropriate coloristic characterization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2463–2470, 2001
Poly(ether ether ketone) solutions suitable for microfiltration membrane preparation
Authors: Vigo Fernando , Castellano Maila
Published: September 2002

Poly(ether ether ketone) shows high stability against chemical and physical agents but is poorly soluble in most common solvents. We tested new solvents to obtain concentrated solutions that we used to prepare microfiltration membranes by the phase‐inversion technique. The prepared membranes were tested by the filtration of oily emulsions, and their structure was studied with scanning electron microscopy. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2550–2555, 2001
Study on mechanical properties of perlite‐filled gamma‐irradiated polypropylene
Authors: Akin‐Öktem G. , Tanrisinibilir S. , Tinçer T.
Published: September 2002

This study covers the preparation and characterization of perlite‐filled polypropylene (PP). The compositions of 15, 30, and 50 % by weight perlite–PP composites were prepared by melt‐mixing. The PP used in this study was either applied in the virgin form or γ‐irradiated in air at the doses of 10, 25, 50, and 100 kGy to determine the effect of oxidative degradation in composite properties. Furthermore, the active sites containing oxygen produced by γ‐irradiation in PP may provide a possible enhancement by the interfacial interaction between perlite and PP. An initial sharp drop in torque readings during the melt‐mixing of perlite–PP composite preparation indicated an extensive chain scission and degradation by γ‐irradiation. The thermal properties of the composites were characterized by DSC. The ultimate tensile strength and elongation and also impact strength decreased in all composites with γ‐irradiation. Yet, these changes appeared not to be faster than was the change in unfilled PP upon irradiation. Scanning electron microscopy revealed an interfacial adhesion between perlite and irradiated PP while virgin PP did not show any evidence of adhesion. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2670–2678, 2001
Facile synthesis and properties of semicrystalline copoly(arylene ether ketone) containing hydroquinone and phthalazinone
Authors: Meng Y. Z. , Tjong S. C.
Published: September 2002

Two series of novel copoly(arylene ether ketone) were successfully synthesized from hydroquinone or bisphenol A, bis(4‐fluorophenyl)ketone and 4‐(4‐hydroxyphenyl)‐2,3‐phthalazin‐1‐one with anhydrous potassium carbonate as the catalyst. The synthesized polymers exhibited high glass‐transition temperatures together with excellent thermooxidative stability. The chain structure of these polymers was studied by means of 13C‐nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC), and wide‐angle X‐ray diffraction (WAXD) techniques. The experimental results showed that these “as‐made” copolyaryleneketones containing hydroquinone moieties exhibited a multiblock chain structure with long segments that mainly consisted mainly of hydroquinone and bis(4‐fluorophenyl)ketone at the middle of the molecular chain. These long segments exhibited crystallites in the produced polymers. The synthesized copolyaryleneketone containing 90 mol % hydroquinone possessed a glass‐transition temperature higher than that of commercial PEEK. The synthesized polymers also exhibited either fair processability or solubility. The glass‐transition temperatures, solubility, and tensile strengths of the two series of copolyaryleneketones tended to increase with increasing phthalazinone moiety content. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2687–2695, 2001
Polyesteramides used for hot melt adhesives: Synthesis and effect of inherent viscosity on properties
Authors: Chen Xuming , Zhong Hua , Jia Lanqin , Ling Jiacheng , Tang Ruiguo , Qiao Jinliang , Zhang Zhongyue
Published: September 2002

Polyesteramides, with different inherent viscosities, were synthesized from dimer acid, sebacic acid, ethylenediamine, and diethylene glycolamine. The effect of inherent viscosity of the polyesteramides on their thermal properties, such as melt viscosity, softening point, heat of fusion, glass‐transition temperature, and low‐temperature flexibility, was studied. The effect of the inherent viscosity on mechanical properties, such as tensile strength, elongation at break, and hardness, and on adhesion properties, such as lap shear strength and T‐peel strength, was also investigated. The results show that melt viscosity, tensile strength, and elongation at break increase as the inherent viscosity increases, and that lap shear strength of the polyesteramides also increases with increasing inherent viscosity, whereas softening point, glass‐transition temperature, and shore D hardness of the polyesteramides essentially do not change as the inherent viscosity increases within a certain range. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2696–2701, 2001
Biodegradable polymers based on renewable resources. V. Synthesis and biodegradation behavior of poly(ester amide)s composed of 1,4:3,6‐dianhydro‐D‐glucitol, α‐amino acid, and aliphatic dicarboxylic acid units
Authors: Okada Masahiko , Yamada Masashi , Yokoe Makito , Aoi Keigo
Published: September 2002

A series of poly(ester amide)s were synthesized by solution polycondensations of various combinations of p‐toluenesulfonic acid salts of O,O′‐bis(α‐aminoacyl)‐1,4:3,6‐dianhydro‐D‐glucitol and bis(p‐nitrophenyl) esters of aliphatic dicarboxylic acids with the methylene chain lengths of 4–10. The p‐toluenesulfonic acid salts were obtained by the reactions of 1,4:3,6‐dianhydro‐D‐glucitol with alanine, glycine, and glycylglycine, respectively, in the presence of p‐toluenesulfonic acid. The polycondensations were carried out in N‐methylpyrrolidone at 40°C in the presence of triethylamine, giving poly(ester amide)s having number‐average molecular weights up to 3.8 × 104. Their structures were confirmed by FTIR, 1H‐NMR, and 13C‐NMR spectroscopy. Most of these poly(ester amide)s are amorphous, except those containing sebacic acid and glycine or glycylglycine units, which are semicrystalline. All these poly(ester amide)s are soluble in a variety of polar solvents such as dimethyl sulfoxide, N,N‐dimethylformamide, 2,2,2‐trifluoroethanol, m‐cresol, pyridine, and trifluoroacetic acid. Soil burial degradation tests, BOD measurements in an activated sludge, and enzymatic degradation tests using Porcine pancreas lipase and papain indicated that these poly(ester amide)s are biodegradable, and that their biodegradability markedly depends on the molecular structure. The poly(ester amide)s were, in general, degraded more slowly than the corresponding polyesters having the same aliphatic dicarboxylic acid units, both in composted soil and in an activated sludge. In the enzymatic degradation, some poly(ester amide)s containing dicarboxylic acid components with shorter methylene chain lengths were degraded more readily than the corresponding polyesters with Porcine pancreas lipase, whereas most of the poly(ester amide)s were degraded more rapidly than the corresponding polyesters with papain. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2721–2734, 2001
Intercalative redox polymerization and characterization of poly(4‐vinylpyridine)–vermiculite nanocomposite
Authors: Dhamodharan R. , Samuel J. D. Jeyaprakash S. , Rajeswari M. K.
Published: September 2002

A new nanocomposite material consisting of poly(4‐vinylpyridine) (PVP) and vermiculite is synthesized by the intercalative redox polymerization of VP in the gallery of copper(II) ion‐exchanged vermiculite. The formation of a single filament of the polymer in the gallery is confirmed by the increase in gallery spacing of 4.7 Å as indicated by X‐ray diffraction (XRD) analysis. Electron spin resonance studies confirm the presence of Cu(II) upon ion exchange and its absence following redox polymerization. The amount of polymer present in the gallery is found to be ∼18–19 mass % by thermogravimetric analysis. Confining the polymer to the gallery spacing in vermiculite results in enhanced thermal stability that is evident from the increase in the initial decomposition temperature by ∼300°C. Differential scanning calorimetry of the nanocomposite indicates that the polymer is confined to a restricted geometry because of the absence of a glass‐transition temperature, which confirms the XRD finding. The IR absorption peaks corresponding to PVP and the expected PVP UV π–π* transition at 275 nm, along with the XRD and thermal data confirms that the gallery expansion is due to the PVP filament. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 555–561, 2001
Polymerization of methylmethacrylate monomer in the presence of dithizone and carbazone complexes
Authors: Hanna Wageih G. , Mekewi Mohamed A. , El‐Mosallamy El‐Said H.
Published: September 2002

It has been proved that lead dithizone and carbazone complexes act as adequate initiators for radical polymerization of methylmethacrylate and also as reliable indicators for the free‐radical mechanism. Lead dithizone complex, in particular, exhibited the phenomenon of color change during the polymerization process, suggesting the use of this complex as a free‐radical indicator and also as a coloring material for acrylic polymers in situ. The color change observed during the polymerization process was attributed to the change in the structure of complex compounds according to a tautomerization mechanism. The presence of lead dithizone and carbazone complexes as initiators exhibited reduced molecular mass compared to those prepared in their absence, indicating their role as regulating agents during the polymerization process. The polydispersity and tacticity parameters were measured through the present work using GPC and 1H–NMR techniques, respectively. The amorphous nature of polymer chains in both the absence and the presence of the lead dithizone and carbazone was studied using X‐ray diffraction, where an increased crystallinity was observed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 562–568, 2001
Graft copolymerization of hydroxyethyl methacrylate onto chitosan
Authors: El‐Tahlawy Khaled , Hudson Samuel M.
Published: September 2002

Chitosan is a polysaccharide derived from chitin, which is commonly found in shellfish waste materials. The present work is concerned with the graft copolymerization of 2‐hydroxyethylmethacrylate (HEMA) onto chitosan using thiocarbonation–potassium bromate for redox initiation. The combined effects of the principal reaction variables for the grafting reaction were studied systematically. This grafting reaction was studied with respect to percentages of graft yield (%G.Y.), homopolymer (%H.P.), and total conversion (%T.C.). A tentative polymerization mechanism is proposed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 683–702, 2001
Glial fibrillary acidic protein‐positive cells of the kidney are capable of raising a protective biochemical barrier similar to astrocytes: Expression of metallothionein in podocytes
Authors: Buniatian Gayane Hrachia , Hartmann Hans‐Jürgen , Traub Peter , Wiesinger Heinrich , Albinus Margitta , Nagel Wolfgang , Shoeman Robert , Mecke Dieter , Weser Ulrich
Published: September 2002

Blood–tissue exchange and homeostasis within the organs depend on various interactions between endothelial and perivascular cells (Buniatian, 2001). Podocytes possess anatomical and cellular features intermediate between those of astrocytes and hepatic stellate cells (HSCs). Podocytes, like HSCs, are associated with fenestrated capillaries and, similar to astrocytes, interact with the capillaries via the basement membrane and participate in permeability‐limiting ultrafiltration. The fact that podocytes come in direct contact with xenobiotics prompted us to investigate whether they express metallothionein (MT), an anticytotoxic system characteristic of astrocytes. In comparative studies, cryosections of 1‐ and 3‐month‐old rat kidney and adult rat brain, as well as podocytes and astrocytes from early and prolonged primary cultures of glomerular explants and newborn rat brain, respectively, were investigated. The cells were double‐labeled with antiserum against glial fibrillary acidic protein (GFAP) and monoclonal antibody (MAb) against the lysine‐containing epitope of Cd/Zn‐MT‐I (MAb MT) or MAb against alpha‐actin. In kidney sections, MT immunoreactivity was detected in GFAP‐positive glomerular cells and in interstitial fibroblasts. The pattern of staining for MT and GFAP in glomerular cells was similar to that of astrocytes in vivo. In glomerular cell cultures, MT was expressed in cobblestone‐like podocytes which contained Wilms' tumor protein and lacked desmin. MT was upregulated at later culture periods, during which podocytes acquired features typical of undifferentiated astrocytes. This study hints at the existence of common regulatory mechanisms of blood–tissue interactions by neural and non‐neural perivascular cells. These mechanisms appear to be used in an organ‐specific manner. Anat Rec 267:296–306, 2002. © 2002 Wiley‐Liss, Inc.
Intraorbital anatomy of the koala (Phascolarctos cinereus)
Authors: Kempster R.C. , Bancroft B.J. , Hirst L.W.
Published: September 2002

This is the first documented study of the anatomical details of the contents of the normal koala orbit, excluding the bulbus oculi. Baseline data were established which are necessary for understanding and treating ocular disease in the koala (Phascolarctos cinereus). The anatomy of the orbital contents of the koala were examined and described from animals that presented dead or were euthanized for humane reasons. Dissections of the orbital cavity were performed under magnification. Polymethyl methacrylate (PMMA) casts of the nasolacrimal system and the vascular supply of the orbit were also made in order to study these systems. The superficial lymphatic drainage of the conjunctival tissues was studied by subcutaneous injection of Evan's Blue into the palpebral conjunctiva of a freshly deceased animal, and by Microfil casts of the efferent lymphatics. In general, the orbital contents of the koala are consistent with those of other carnivorous polyprotodont and herbivorous diprotodont marsupials. Anat Rec 267:277–287, 2002. © 2002 Wiley‐Liss, Inc.
Size and shape changes during late fetal growth (137–157 gestational days) in the pigtailed macaque (Macaca nemestrina) craniofacial complex: An application using three‐dimensional coordinate data and finite element scaling analysis
Authors: Zumpano Michael P.
Published: September 2002

Form changes within the fetal pigtailed macaque (Macaca nemestrina) craniofacial complex was documented using finite element scaling analysis (FESA) and three‐dimensional (3D) coordinate data for 35 craniofacial landmarks. Coordinate data were digitized from 3D reconstructions of computed tomography (CT) images and 2D axial slices. Twenty‐two fetal pigtailed macaques ranging in age from 137 to 157 gestational days were included (in this species, birth is estimated at 170 gestational days). The null hypothesis that the craniofacial complex grows with isometry during late fetal growth of the craniofacial complex was tested (P < 0.05), and the prediction that morphological change along an anteroposterior axis dominates late fetal growth was also investigated. The null hypothesis was rejected, indicating that allometric growth is present during late fetal growth. Growth along an anteroposterior axis is localized in the palate and mandible. The neurocranium grows along a superoinferior axis, while the neurofacial junction displays growth along both the anteroposterior and superoinferior axes. Mediolateral changes are localized between asterions, the external auditory meati, and maxillary and mandibular alveolar points. Finally, a 3D model of craniofacial growth for this species was created, localizing size and shape changes that occur during late fetal growth for each of the 35 craniofacial landmarks defined in this study. Anat Rec 267:307–320, 2002. © 2002 Wiley‐Liss, Inc.
Immunohistochemical localization of heat shock protein 25 (HSP 25) during root formation of the rat molar
Authors: Onishi Tomoyuki , Tsubone Hanako , Ooshima Takashi , Sobue Shizuo , El‐Sharaby Ashraf , Wakisaka Satoshi
Published: September 2002

The present study investigated the immunohistochemical localization of heat shock protein 25 (HSP 25) of rat molar teeth during root formation. Most, probably all, cells of the epithelial rest of Malassez (ERM cells) had immunoreaction for laminin, a marker protein for basement membrane. During root formation, HSP 25 immunoreactivity was observed in odontoblasts, cells at the subodontoblastic layer, and those in close proximity to the acellular cementum. HSP 25‐immunopositive cells at the subodontoblastic layer were present only at the apical region. Most HSP 25‐immunoreactive cells in close proximity to the cementum lacked laminin immunoreactivity. However, at postnatal day 28 a small number of cells showed immunoreaction for both HSP 25 and laminin at the cervical and bifurcational regions. Under the electron microscope, most HSP 25‐immunoreactive cells along the surface of the cementum were round and contained rich organelles such as mitochondria and rough endoplasmic reticulum. They lay between fiber bundles of the periodontal ligament. The localization and morphological features of these HSP 25‐immunoreactive cells resemble those of cementoblasts. On the other hand, HSP 25‐immunoreactive cells at the cervical region were oval and contained few cell organelles. They were closely apposed to each other, and separated from the surrounding tissues with basal lamina. These features were similar to those of mature ERM cells. In contrast, cells with microvillus‐like processes and relatively rich mitochondoria, which were similar to immature ERM cells, had no immunoreaction for HSP 25. These results suggest that HSP 25 may be involved in shape alterations of ERM cells, cementoblasts, and odontoblasts during differentiation. Anat Rec 267:321–329, 2002. © 2002 Wiley‐Liss, Inc.
Comparison of seismic reflection and ground‐penetrating radar imaging at the controlled archaeological test site, Champaign, Illinois
Authors: Hildebrand J. A. , Wiggins S. M. , Henkart P. C. , Conyers L. B.
Published: September 2002

Shallow seismic reflection and ground‐penetrating radar images were collected at a replicated burial mound in the Controlled Archaeological Test Site (CATS) in Champaign, Illinois. The CATS mound contains a pig burial within a wood‐lined crypt at a depth of 1.6–2.4 m. Seismic reflection data were collected from two different energy sources: a small (0.5 kg) hammer for an impulsive source, and a vibrator for a frequency swept source. Seismic data were collected at densely spaced points (5 cm) along a line of 48 geophone receivers. These data were stacked in a common mid‐point gather, band‐pass filtered, and processed with frequency–wavenumber migration. The seismic image produced by the hammer source was dominated by bodywaves at 120 Hz, whereas the vibrator source image was dominated by surface waves at 70 Hz. Both seismic sources revealed clear reflections from the burial crypt, and placed the top of the crypt at the correct depth with a seismic velocity of 120 m s−1. The bottom of the crypt was poorly defined by the seismic data owing to multiple reflections within the crypt. The vibrator source also revealed a high‐frequency (360 Hz) reflector at 2.7 m depth within the mound, perhaps due to a resonant cavity within the pig's body. Single channel ground‐penetrating radar data were processed with the same approach, including band‐pass filtering and migration. The radar data reveal clear reflections from the burial crypt. Extremely fast radar velocities (260 mm ns−1) are required in the upper portion of the burial mound to place the top of the crypt at its correct depth. The bottom of the crypt was well defined by ground‐penetrating radar, and was located accurately with respect to the top of the crypt with a moderate radar velocity (170 mm ns−1). The application of both seismic reflection and ground‐penetrating radar to the same site may be beneficial for improved understanding of their abilities for shallow subsurface imaging. Copyright © 2002 John Wiley & Sons, Ltd.
Atherosclerosis in rheumatoid arthritis: Morphologic evidence obtained by carotid ultrasound
Authors: Park Yong‐Beom , Ahn Chul‐Woo , Choi Hyon K. , Lee Seung‐Hoon , In Byung‐Hyun , Lee Hyun‐Chul , Nam Chung‐Mo , Lee Soo‐Kon
Published: September 2002

Objective

Recent studies have suggested increased cardiovascular disease among patients with rheumatoid arthritis (RA). We undertook this study to obtain morphologic evidence of subclinical atherosclerosis in RA patients.

Methods

We used high‐resolution B‐mode ultrasound to compare carotid artery intima‐media wall thickness (IMT) between 53 postmenopausal women with RA and 53 controls matched by age, sex, and menopause status. No subject in either group had a history of atherosclerosis or its complications. We investigated the association between IMT and relevant clinical and therapeutic variables, including the impact of low‐dose corticosteroid therapy (≤10 mg/day prednisolone).

Results

The mean ± SD IMT of the left and right common carotid arteries in RA patients was significantly greater than that in controls (0.77 ± 0.09 mm versus 0.68 ± 0.14 mm; P < 0.001). Early RA (duration ≤1 year) was associated with lesser IMT than was RA of longer duration (0.72 ± 0.03 mm versus 0.78 ± 0.01 mm; P < 0.04). Prednisolone use was not associated with increased IMT (0.78 ± 0.02 mm in nonusers versus 0.76 ± 0.01 mm in users; P = 0.38).

Conclusion

Our data indicate that RA patients have an ultrasonic marker of early atherosclerosis consistent with an increased risk for atherosclerosis.
Hormonal and reproductive risk factors for development of systemic lupus erythematosus: Results of a population‐based, case–control study
Authors: Cooper Glinda S. , Dooley Mary Anne , Treadwell Edward L. , St.Clair E. William , Gilkeson Gary S.
Published: September 2002

Objective

Estrogen and prolactin may accelerate the progression of murine systemic lupus erythematosus (SLE). In humans, 85% of lupus patients are women, which also suggests the importance of hormonal factors in disease pathogenesis. The purpose of this study was to examine hormonal and reproductive risk factors for lupus among women.

Methods

This population‐based, case–control study included 240 female SLE patients diagnosed between January 1, 1995 and July 31, 1999 who fulfilled the American College of Rheumatology classification criteria. Female controls (n = 321) were identified through driver's license records. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) as measures of association, adjusting for age, state, race, and education. Analyses were limited to exposures before diagnosis.

Results

Breast‐feeding was associated with a decreased risk of developing SLE (OR 0.6, 95% CI 0.4–0.9), with a statistically significant trend for number of babies breast‐fed and total weeks of breast‐feeding. There were no associations with number of pregnancies or live births. Natural menopause occurred earlier in women with subsequent development of SLE compared with controls (P < 0.001). There was little association between SLE and current use or duration of use of hormone replacement therapy or oral contraceptives, and no association with previous use of fertility drugs.

Conclusion

We found little evidence that estrogen‐ or prolactin‐related exposures are associated with an increased risk of lupus. The reduced risk observed among women who had breast‐fed one or more babies should be examined in other studies. Early natural menopause, rather than decreasing risk of SLE because of reduced estrogen exposure, may be a marker of susceptibility to development of SLE.
Finer linkage mapping of primary hip osteoarthritis susceptibility on chromosome 11q in a cohort of affected female sibling pairs
Authors: Chapman Kay , Mustafa Zehra , Dowling Barbara , Southam Lorraine , Carr Andrew , Loughlin John
Published: September 2002

Objective

To finer linkage‐map a primary osteoarthritis (OA) susceptibility locus as a prerequisite to linkage disequilibrium/association analysis.

Methods

A 50‐cM interval of chromosome 11q that we had previously identified as harboring susceptibility to hip OA in a female sibling‐pair cohort was subjected to finer linkage mapping. Thirty‐five microsatellite markers with a mean marker interval of 1.4 cM were genotyped in 146 families containing female sibling pairs who were concordant for hip OA, as ascertained by total hip replacement.

Results

Two‐point and multipoint linkage analysis revealed 2 distinct regions of linkage within the 50‐cM interval. The first locus had a linkage interval of 11.9 cM and was centered at 81.5 cM from the 11p telomere, with a maximum multipoint logarithm of odds (LOD) score of 2.4. The second region had a linkage interval of 6.5 cM and was centered at 93.1 cM from the 11p telomere, with a maximum multipoint LOD score of 1.8.

Conclusion

Dense linkage mapping has highlighted the presence of 2 loci on chromosome 11q, each conferring susceptibility to hip OA. Both loci are sufficiently narrow for association analysis to be undertaken.
Empirical modelling of the DEM/USD and DEM/JPY foreign exchange rate: Structural shifts in GARCH‐models and their implications
Authors: Herwartz Helmut , Reimers Hans‐Eggert
Published: September 2002

We analyse daily changes of two log foreign exchange (FX) rates involving the Deutsche Mark (DEM) for the period 1975–1998, namely FX‐rates measured against the US dollar (USD) and the Japanese yen (JPY). To account for volatility clustering we fit a GARCH(1,1)‐model with leptokurtic innovations. Its parameters are not stable over the sample period and two separate variance regimes are selected for both exchange rate series. The identified points of structural change are close to a change of the monetary policies in the US and Japan, the latter of which is followed by a long period of decreasing asset prices. Having identified subperiods of homogeneous volatility dynamics we concentrate on stylized facts to distinguish these volatility regimes. The bottom level of estimated volatility turns out be considerably higher during the second part of the sample period for both exchange rates. A similar result holds for the average level of volatility and for implied volatility of heavily traded at the money options. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of two methods of introducing foods during feeding treatment on acceptance of previously rejected items
Authors: Ahearn William H.
Published: September 2002

The effects of using a single food item (e.g. bread) versus using multiple items (e.g. bread, pasta, and rice) when establishing food acceptance via an escape prevention procedure were investigated with six children who presented with food selectivity. Eating was exposed to a differential reinforcement of food acceptance treatment package but food acceptance did not improve. Criterion levels of appropriate eating (> 80% acceptance, < 20% expulsion, and < 20% disruption) were subsequently established with either nonremoval of the spoon or physical guidance for each of the participants. Three of the children were presented with only one food item during acquisition of acceptance. The other children were presented with three different food items from the same food group. It was found that acquisition of acceptance was more rapid for the single‐item group but that food acceptance was more likely to generalize to previously rejected items for the multi‐item group. The implications for clinical intervention are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Identifying operant functions for tics in children with mental retardation
Authors: Richman David M. , Lindauer Steve E.
Published: September 2002

Functional analyses were used to assess the effects of environmental consequences on occurrences of repetitive vocal behavior that had been diagnosed as chronic vocal tics in two adolescent males with mental retardation. The functional analyses indicated that one participant's tics were sensitive to positive reinforcement in the form of caregiver attention, while the second participant's tics occurred independent of social consequences. The results are discussed in terms of using functional analysis methodology during assessment, diagnosis, and treatment selection for suspected tics. Copyright © 2002 John Wiley & Sons, Ltd.
Conformational dynamics of helix S6 from Shaker potassium channel: Simulation studies
Authors: Bright Joanne N. , Shrivastava Indira H. , Cordes Frank S. , Sansom Mark S. P.
Published: September 2002

Prolines in transmembrane (TM) α‐helices are believed to play an important structural and/or functional role in membrane proteins. At a structural level a proline residue distorts α‐helical structure due to the loss of at least one stabilizing backbone hydrogen bond, and introduces flexibility in the helix that may result in substantial kink and swivel motions about the effective “hinge.” At a functional level, for example in Kv channels, it is believed that proline‐induced molecular hinges may have a direct role in gating, i.e., the conformational change linked to opening/closing the channel to movement of ions. In this article we study the conformational dynamics of the S6 TM helix from of the Kv channel Shaker, which possesses the motif PVP—a motif that is conserved in Kv channels. We perform multiple molecular dynamics simulations of single S6 helices in a membrane‐mimetic environment in order to effectively map the kink–swivel conformational space of the protein, exploiting the ability of multiple simulations to achieve greater sampling. We show that the presence of proline locally perturbs the helix, disrupting local dihedral angles and producing local twist and unwinding in the region of the hinge—an effect that is relaxed with distance from the PVP motif. We furthermore show that motions about the hinge are highly anisotropic, reflecting a preferred region of kink–swivel conformation space that may have implications for the gating process. © 2002 Wiley Periodicals, Inc. Biopolymers 64: 303–313, 2002
Self‐aggregation properties of spin‐labeled zervamicin IIA as studied by PELDOR spectroscopy
Authors: Milov A. D. , Tsvetkov Yu. D. , Gorbunova E. Yu. , Mustaeva L. G. , Ovchinnikova T. V. , Raap J.
Published: September 2002

In this article, the pulsed double electron–electron resonance in electron spin‐echo (PELDOR) technique is applied to study the self‐aggregation of spin‐labeled zervamicin IIA, a hexadecapeptide antibiotic of fungal origin, which is known to form ion channels in a phospholipid double layer. Measurements of the ion channel forming properties and the antibiotic activity of the analog indicate that replacement of the C‐terminal phenylalaninol by the amino‐2,2,6,6‐tetramethylpiperidinyloxy (TEMPO) residue does not influence the biophysical and biological properties. The dipole–dipole interaction between the spin labels of the fully biologically active peptide analog was studied in frozen (77 K) glassy solutions in different ratios of toluene–methanol. The spin‐labeled zervamicin IIA molecules were shown to form aggregates. An average distance between the spin labels in the aggregates was estimated to be in the range of 25–35 Å (depending on the solvent composition), indicating that the amphiphilic helical peptide molecules are oriented in an antiparallel fashion. Increasing of methanol content in the solution results in a loosening of the aggregate structure. It was shown that the fraction of aggregated zervamicin IIA molecules is less than 44–67% depending on the solvent composition. The general usefulness of the method to obtain structural long‐range information in a range of several tens of angstroms is demonstrated by comparison with the peptide cluster of trichogin GA IV. © 2002 Wiley Periodicals, Inc. Biopolymers 64: 328–336, 2002
Yeast‐mediated preparation of l‐PAC in an organic solvent
Authors: Kostraby Margaret M. , Smallridge Andrew J. , Trewhella Maurie A.
Published: September 2002

The yeast‐mediated acyloin condensation of benzaldehyde and pyruvic acid to form l‐PAC occurs in a petroleum spirit solvent system at room temperature with moderate conversion (30%) and high enantioselectivity (86%ee) after 24 h. The addition of a small amount of ethanol (0.5% mL) to the reaction mixture inhibits the formation of the side product benzyl alcohol and increases the conversion to l‐PAC. Conducting the reaction using 13C‐labeled pyruvate indicated that the pyruvate was incorporated into the l‐PAC and that the excess pyruvate was converted into ethanol. Conducting the reaction at 5°C results in similar conversion but higher enantioselectivity. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 827–831, 2002; DOI 10.1002/bit.10117
Substrate inhibition mode of ω‐transaminase from Vibrio fluvialis JS17 is dependent on the chirality of substrate
Authors: Shin Jong‐Shik , Kim Byung‐Gee
Published: September 2002

Substrate inhibition is a common phenomenon in enzyme chemistry, which is observed only with a fast‐reacting substrate enantiomer. We report here for the first time substrate inhibition of an enantioselective enzyme by both substrate enantiomers. The enantioselective substrate inhibition, i.e., different mode of inhibition by each substrate enantiomer, of (S)‐specific ω‐transaminase was found with various chiral amines. A kinetic model based on ping‐pong bi‐bi mechanism has been developed and kinetic parameters were measured. The kinetic model reveals that the inhibition by (R)‐amine results from formation of Michaelis complex with enzyme‐pyridoxal 5′‐phosphate, whereas the inhibition by (S)‐amine results from the formation of the complex with enzyme‐pyridoxamine 5′‐phosphate. Substrate inhibition constants (KSI) of each (S)‐enantiomer of four chiral amines showed a linear correlation with those of cognate (R)‐amines. Such a correlation was also found between the KSI values and Michaelis constants of (S)‐amines. These correlations indicate that recognition mechanisms and active site structures of both enzyme‐pyridoxal 5′‐phosphate, enzyme‐pyridoxamine 5′‐phosphate are similar. Taken together with the results, high propensity for non‐productive substrate binding strongly suggests that binding pockets of the ω‐transaminase is loosely defined, which accounts for the enantioselective substrate inhibition. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 832–837, 2002; DOI 10.1002/bit.10165
Application of neural network for simulation of upflow anaerobic sludge blanket (UASB) reactor performance
Authors: Sinha Sucheta , Bose Purnendu , Jawed Mohammed , John Siby , Tare Vinod
Published: September 2002

Up‐flow anaerobic sludge blanket (UASB) reactors are being used with increasing regularity all over the world, especially in India, for a variety of wastewater treatment operations. Consequently, there is a need to develop methodologies enabling one to determine UASB reactor performance, not only for designing more efficient UASB reactors but also for predicting the performance of existing reactors under various conditions of influent wastewater flows and characteristics. This work explores the feasibility of application of an artificial neural network‐based model for simulating the performance of an existing UASB reactor. Accordingly, a neural network model was designed and trained to predict the steady‐state performance of a UASB reactor treating high‐strength (unrefined sugar based) wastewater. The model inputs were organic loading rate, hydraulic retention time, and influent bicarbonate alkalinity. The output variables were one or more of the following, effluent substrate concentration (Se), reactor bicarbonate alkalinity, reactor pH, reactor volatile fatty acid concentration, average gas production rate, and percent methane content of the gas. Training of the neural network model was achieved using a large amount of experimentally obtained reactor performance data from the reactor mentioned above as the training set. Training was followed by validation using independent sets of performance data obtained from the same UASB reactor. Subsequently, simulations were performed using the validated neural network model to determine the impact of changes in parameters like influent chemical oxygen demand (COD) concentration and hydraulic retention time on the reactor performance. Simulation results thus obtained were carefully analyzed based on qualitative understanding of UASB process and were found to provide important insights into key variables that were responsible for influencing the working of the UASB reactor under varying input conditions. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 806–814, 2002; DOI 10.1002/bit.10168
Characterizing the adhesion of motile and nonmotile Escherichia coli to a glass surface using a parallel‐plate flow chamber
Authors: McClaine Jennifer W. , Ford Roseanne M.
Published: September 2002

A parallel‐plate flow chamber was used to measure the attachment and detachment rates of Escherichia coli to a glass surface at various fluid velocities. The effect of flagella on adhesion was investigated by performing experiments with several E. coli strains: AW405 (motile); HCB136 (nonmotile mutant with paralyzed flagella); and HCB137 (nonmotile mutant without flagella). We compared the total attachment rates and the fraction of bacteria retained on the surface to determine how the presence and movement of the flagella influence transport to the surface and adhesion strength in this dynamic system. At the lower fluid velocities, there was no significant difference in the total attachment rates for the three bacterial strains; nonmotile strains settled at a rate that was of the same order of magnitude as the diffusion rate of the motile strain. At the highest fluid velocity, the effect of settling was minimized to better illustrate the importance of motility, and the attachment rates of both nonmotile strains were approximately five times slower than that of the motile bacteria. Thus, different processes controlled the attachment rate depending on the parameter regime in which the experiment was performed. The fractions of motile bacteria retained on the glass surface increased with increasing velocity, whereas the opposite trend was found for the nonmotile strains. This suggests that the rotation of the flagella enables cells to detach from the surface (at the lower fluid velocities) and strengthens adhesion (at higher fluid velocities), whereas nonmotile cells detach as a result of shear. There was no significant difference in the initial attachment rates of the two nonmotile species, which suggests that merely the presence of flagella was not important in this stage of biofilm development. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 179–189, 2002; DOI 10.1002/bit.10192
Electrochemical monitoring of cell behaviour in vitro: A new technology
Authors: Woolley D. E. , Tetlow L. C. , Adlam D. J. , Gearey D. , Eden R. D.
Published: September 2002

This article describes a novel electrochemical technique for the real‐time monitoring of changes in the behaviour of adherent human cells in vitro: i.e., a biosensor that combines a biological recognition mechanism with a physical transduction technique, described collectively as Oncoprobe. Confluent viable cells adherent to gold electrodes (sensors) modify the extracellular microenvironment at the cell:sensor interface to produce a change in the electrochemical potential compared to that measured in the absence of cells. The potential was measured as an open circuit potential (OCP) with respect to a saturated calomel reference in the bulk culture medium. Typical OCP values for confluent cultures of human breast carcinoma cells, 8701‐BC, approximated −100mV compared with cell‐free values of approximately −15mV. The OCP for 8701‐BC cells was modified in response to temperature changes over the range 32 to 40°C and also to treatments with phytohemagglutinin (PHA, 25 μg/mL), cycloheximide (30 μM) and interleukin‐1 β (IL‐1, 0.5 ng/mL) over 24 h. Cultures of synovial fibroblasts also responded to the same treatments with similar responses, producing negative shifts in the OCP signal with PHA and IL‐I, but a positive shift in OCP signal with cycloheximide, all relative to the untreated control cultures. From experimental data and theoretical considerations it is proposed that the cell‐derived signals are mixed electrode potentials reflecting a “conditioned,” more reducing environment at the cell:sensor interface. Only viable cells caused a negative shift in the OCP signal, this being lost when cells were rendered nonviable by formalin exposure. This technology appears unique in its ability to passively “listen in” on cell surface activities, suggesting numerous applications in the fields of drug discovery, chemotherapy, and cell behaviour © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 725–733, 2002; DOI 10.1002/bit.10217
Sol‐gel encapsulated enzyme arrays for high‐throughput screening of biocatalytic activity
Authors: Park Chan B. , Clark Douglas S.
Published: September 2002

We developed versatile low‐cost arrays of sol‐gel‐encapsulated enzymes (referred to as solzymes) suitable for repeated assays of bioactivity or enzyme inhibition. Sol‐gel microstructures containing active enzymes were stabilized on glass at moderate pH and room temperature without harsh calcination. A multi‐well bilayer of polydimethylsiloxane was used to support the solzyme array and contain the reaction medium. Each of the 147 microwells has a working volume of 5 μL and contains 50 μg of immobilized enzyme. The solzyme arrays maintained high activity through repeated applications and exhibited superior thermostability compared to soluble enzymes. Among the enzymes used were lipases, glucose oxidase, and horseradish peroxidase. Twenty different lipases and proteases were also used to prepare a hydrolase array, for which bromthymol blue served as a generic indicator of activity. The relative activities of the encapsulated hydrolases correlated closely with those of the soluble hydrolases, illustrating that sol‐gel encapsulation preserved the hierarchy of enzyme activity. The development of solzyme arrays paves the way to higher throughput screening of diverse proteins and enzymes, including those that are available only in trace amounts. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 229–235, 2002; DOI 10.1002/bit.10238