bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quadricepsplasty for knee stiffness after femoral lengthening in congenital short femur
Authors: Hosalkar H. S. , Jones S. , Chowdhury M. , Hartley J. , Hill R. A. 
Published: March 2003

We review the results of a modified quadricepsplasty in five children who developed stiffness of the knee after femoral lengthening for congenital short femur using an Ilizarov external fixator which spanned the knee. All had a full range of movement of the knee before lengthening was undertaken. Unifocal lengthening was carried out in the distal metaphysiodiaphyseal region of the distal femur with a mean gain of 6.5 cm. The mean percentage lengthening was 24%. At the end of one year after removal of the Ilizarov frame and despite intensive physiotherapy all patients had stiffness. Physiotherapy was continued after the quadricepsplasty and, at the latest follow-up (mean 27 months), the mean active flexion was 102° (80 to 130). The gain in movement ranged from 50° to 100°. One patient had a superficial wound infection which settled after a course of oral antibiotics. None developed an increased extension lag after surgery and all were very satisfied with the results. Quadricepsplasty is a useful procedure for stiffness of the knee after femoral lengthening which has not responded to physiotherapy.
Turn-up bone flap for lengthening the below-knee amputation stump
Authors: Pant R. , Younge D. 
Published: March 2003

When amputation just below the knee becomes necessary after extensive loss of bone from the tibia and of anterior soft tissue in the treatment of tumours, fractures or infection, the remaining proximal tibia may be too short for a below-knee prosthesis, although the knee may be normal. We have included the distal tibia or foot in a long posterior flap by turning it up thus increasing the length of a very short proximal tibial stump. The knee is thereby saved, allowing satisfactory use of a below-knee prosthesis. This technique is particularly applicable when the distal leg is normal and well vascularised. Five procedures have been undertaken. We present two illustrative cases.
Bone mineral density in long-term survivors of highly malignant osteosarcoma
Authors: Holzer G. , Krepler P. , Koschat M. A. , Grampp S. , Dominkus M. , Kotz R. 
Published: March 2003

We studied the bone mineral density (BMD) of 48 long-term survivors of highly malignant osteosarcoma who had been treated according to the chemotherapy protocols of the German- Swiss-Austrian Co-operative Osteosarcoma Study Group which include high-dose methotrexate. The mean age of the patients was 31 ± 4.2 years and the mean follow-up 16 ± 2.2 years. The BMD of the lumbar spine and of the proximal femur of the non-operated side was measured by dual- energy x-ray absorptiometry. A questionnaire was given to determine life-style factors, medical history and medication. Ten patients were osteoporotic, 21 osteopenic and 17 normal according to the WHO definition. Eighteen patients suffered fractures after receiving chemotherapy and all had significantly lower levels of BMD for all the sites measured.
Blood Lead, Blood Pressure, and Hypertension in Perimenopausal and Postmenopausal Women
Authors: Nash Denis , Magder Laurence , Lustberg Mark , Sherwin Roger W. , Rubin Robert J. , Kaufmann Rachel B. , Silbergeld Ellen K. 
Published: March 2003

ContextLead exposures have been shown to be associated with increased blood pressure and risk of hypertension in older men. In perimenopausal women, skeletal lead stores are an important source of endogenous lead exposure due to increased bone demineralization.ObjectiveTo examine the relationship of blood lead level with blood pressure and hypertension prevalence in a population-based sample of perimenopausal and postmenopausal women in the United States.Design, Setting, and ParticipantsCross-sectional sample of 2165 women aged 40 to 59 years, who participated in a household interview and physical examination, from the Third National Health and Nutrition Examination Survey conducted from 1988 to 1994.Main Outcome MeasuresAssociations of blood lead with blood pressure and hypertension, with age, race and ethnicity, cigarette smoking status, body mass index, alcohol use, and kidney function as covariates.ResultsA change in blood lead levels from the lowest (quartile 1: range, 0.5-1.6 µg/dL) to the highest (quartile 4: range, 4.0-31.1 µg/dL) was associated with small statistically significant adjusted changes in systolic and diastolic blood pressures. Women in quartile 4 had increased risks of diastolic (&amp;gt;90 mm Hg) hypertension (adjusted odds ratio [OR], 3.4; 95% confidence interval [CI], 1.3-8.7), as well as moderately increased risks for general hypertension (adjusted OR, 1.4; 95% CI, 0.92-2.0) and systolic (&amp;gt;140 mm Hg) hypertension (adjusted OR, 1.5; 95% CI, 0.72-3.2). This association was strongest in postmenopausal women, in whom adjusted ORs for diastolic hypertension increased with increasing quartile of blood lead level compared with quartile 1 (adjusted OR, 4.6; 95% CI, 1.1-19.2 for quartile 2; adjusted OR, 5.9; 95% CI, 1.5-23.1 for quartile 3; adjusted OR, 8.1; 95% CI, 2.6-24.7 for quartile 4).ConclusionsAt levels well below the current US occupational exposure limit guidelines (40 µg/dL), blood lead level is positively associated with both systolic and diastolic blood pressure and risks of both systolic and diastolic hypertension among women aged 40 to 59 years. The relationship between blood lead level and systolic and diastolic hypertension is most pronounced in postmenopausal women. These results provide support for continued efforts to reduce lead levels in the general population, especially women.
Multiple Sclerosis and Epstein-Barr Virus
Authors: Levin Lynn I. , Munger Kassandra L. , Rubertone Mark V. , Peck Charles A. , Lennette Evelyne T. , Spiegelman Donna , Ascherio Alberto 
Published: March 2003

ContextInfection with Epstein-Barr virus (EBV) has been associated with an increased risk of multiple sclerosis (MS), but the temporal relationship remains unclear.ObjectiveTo determine whether antibodies to EBV are elevated before the onset of MS.Design, Setting, and PopulationNested case-control study conducted among more than 3 million US military personnel with blood samples collected between 1988 and 2000 and stored in the Department of Defense Serum Repository. Cases were identified as individuals granted temporary or permanent disability because of MS. For each case (n = 83), 2 controls matched by age, sex, race/ethnicity, and dates of blood sample collection were selected.Main Outcome MeasuresAntibodies including IgA against EBV viral capsid antigen (VCA) and IgG against VCA, nuclear antigens (EBNA complex, EBNA-1, and EBNA-2), diffuse and restricted early antigens, and cytomegalovirus.ResultsThe average time between blood collection and MS onset was 4 years. The strongest predictors of MS were serum levels of IgG antibodies to VCA or EBNA complex. The risk of MS increased monotonically with these antibody titers; relative risk (RR) in persons in the highest category of VCA (≥2560) compared with those in the lowest (≤160) was 19.7 (95% confidence interval [CI], 2.2-174; P for trend = .004). For EBNA complex titers, the RR for those in the highest category (≥1280) was 33.9 (95% CI, 4.1-283; P for trend &amp;lt;.001) vs those in the lowest category (≤40). Similarly strong positive associations between EBV antibodies and risk of MS were already present in samples collected 5 or more years before MS onset. No association was found between cytomegalovirus antibodies and MS.ConclusionThese results suggest a relationship between EBV infection and development of MS.
Preparation and properties of heat‐shrinkable cross‐linked low‐density polyethylene
Authors: Morshedian J. , Khonakdar H. A. , Mehrabzadeh M. , Eslami H. 
Published: March 2003

AbstractIn this work, heat‐shrinkable characteristics of a polyethylene compound were obtained by blending mixtures of low‐density polyethylene with varying amount of peroxide. These were then extruded and molded to the required shape and then cross‐linked by chemical means, followed by heating and stretching and then cooled to “freeze‐in” the oriented polymer structure (elastic memory). A decrease in the melting point and heat of fusion (ΔHf), as determined from the DSC melting enthalpies, was observed with an increase in the dicumyl peroxide (DCP) concentration. Tests on the heat shrinkablity of the samples showed that the stretching temperature has a large effect on the shrinkage temperature. The results showed that by increasing the peroxide content, the shrinkage temperature was decreased. The elongation at break decreased with an increase in the DCP concentration. Increasing the temperature in lightly cross‐linked samples (low percent DCP) resulted in a reduction in the elongation at break. Increasing the cross‐linking density (DCP content) gave an opposite effect. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 112–119, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10041
Continuous production of ultrathin polymeric nanofilms using the spontaneous film formation technique
Authors: Hinrichsen Georg , Hoffmann Andreas , Schleeh Thomas , Macht Christian 
Published: March 2003

AbstractThe paper deals with a unique continuous laboratory process for the manufacture of ultrathin nanofilms of various thermoplastic polymers, such as polycarbonate, polyetherimide, polysulfone, and liquid crystalline polyester, based upon the recently developed spontaneous film formation technique. Continuous films with a width up to 14 cm and a thickness of 20–100 nm were produced using a prototype laboratory apparatus at a windup velocity of 1–20 m/min. The length of the film can be almost infinite, i.e. longer than 1 km. The produced films are of high quality and can be used as layer materials, as membranes, in optical devices and sensors, as well as for microlithographic purposes. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 120–125, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10042
Nanoparticles from a controlled polymerization process
Authors: Tirumala Vijaya R. , Caneba Gerard T. , Dar Yadunandan , Wang Hsien‐Hau , Mancini Derrick C. 
Published: March 2003

AbstractFree‐radical retrograde precipitation polymerization process in the past has shown excellent control characteristics over reaction rate, molecular weight, and in the entrapment of live radicals for the generation of block copolymers. The same principle has now been extended to study the reaction confinement to a nanoscale region. Nanosized polymer particles have been reported to form from block copolymers, conventional precipitation polymerization methods, or through emulsion polymerization approaches. In this work, we present a new method of generating nanosized polymer particles by polymerizing the monomer in an environment that precipitates the polymer above the lower critical solution temperature. The nanoparticles have been characterized by both tapping‐mode atomic force microscopy observations and in situ synchrotron time‐resolved small‐angle X‐ray scattering analysis. The results from both the techniques showed the formation of nanoparticles in the size range of 15–30 nm, directly from the polymerization process. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 126–136, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10043
Processing characteristics of PET/PEN blends, part 1: Extrusion and transesterification reaction kinetics
Authors: Tharmapuram Sriram R. , Jabarin Saleh A. 
Published: March 2003

AbstractBlends of poly(ethylene terephthalate)/poly(ethylene 2,6‐naphthalene dicarboxylate) (PET/PEN) have exhibited properties that are of commercial interest to the packaging industry. Melt processing of PET with PEN results in transesterification reactions. The blend properties are controlled by the kinetics of these reactions. The chemical kinetics equations have been modified to predict theoretical processing temperatures required for different blend compositions to achieve critical levels of transesterification. These values are found to be in close agreement with the experimentally observed values obtained for blends processed in a twin‐screw extruder. The critical transesterification temperature is dependent on the equilibrium melting point of the miscible blend and the nature of the PET and PEN resins used for preparing the blend. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 137–146, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10044
Processing characteristics of PET/PEN blends, part 2: Rheology and degradation kinetics
Authors: Tharmapuram Sriram R. , Jabarin Saleh A. 
Published: March 2003

AbstractBlends and copolyesters of poly(ethylene terephthalate)/poly(ethylene 2,6‐naphthalene dicarboxylate), PET/PEN, have shown promise in high performance container applications. In the first part of this series on the processing characteristics of PET/PEN blends, we investigated the applicability of reaction kinetics to predict the critical transesterification temperature during processing and the influence of the equilibrium melting point of the miscible blends on the critical transesterification temperature. In the present work, we have studied both the rheology and degradation kinetics of the blends as a function of material composition. Melt viscosity loss was measured as a function of time and temperature. Activation energies for degradation were calculated from experimental data. Results show that blends containing a minimum of 10% PEN by weight are as stable as PEN in terms of thermal and thermal‐oxidative degradation. Addition of low amounts of PEN to PET causes a depression in melt viscosity. A critical composition of 10% PEN by weight is required before an increase in blend viscosity is observed. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 147–154, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10045
Processing characteristics of PET/PEN blends, part 3: Injection molding and free blow studies
Authors: Tharmapuram Sriram R. , Jabarin Saleh A. 
Published: March 2003

AbstractThe injection molding and orientation characteristics of poly(ethylene terephthalate) (PET) and poly(ethylene terephthalate)/poly(ethylene 2,6‐naphthalene dicarboxylate) (PET/PEN) blends are discussed. Injection molding was carried out to produce preforms with good optical clarity. The difference between the processing temperature and the equilibrium melting point of the materials, their crystallizability, and their levels of transesterification are major factors controlling optical clarity in the preforms. Free blow experiments were conducted on the injection‐molded preforms to study changes in the blow‐up ratio (BUR) as a function of molecular weight, blend composition, level of transesterification, and the difference between the orientation temperature and the glass‐transition temperature (T – Tg). Results indicate that for a given value of intrinsic viscosity and T – Tg, the blends will require higher stretch ratios than that of PET to achieve equivalent levels of strain‐induced crystallization. The BUR for a given blend composition is independent of the degree of randomness after a critical level of transesterification has been achieved. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 155–167, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10046
Melt spinning and drawing of 2‐methyl‐1,3‐propanediol‐substituted poly(ethylene terephthalate)
Authors: Suh Jaein , Spruiell J. E. , Schwartz Steven A. 
Published: March 2003

AbstractThe structure and properties of fibers prepared from copolymers of poly(ethylene terephthalate) (PET) in which 2‐methyl‐1,3‐propanediol (MPDiol® Glycol is a registered trademark of Lyondell Chemical Company) at 4, 7, 10, and 25 mol% was substituted for ethylene glycol were studied and compared with those of PET homopolymer. Filaments were melt spun over a range of spinning conditions, and some filaments that were spun at relatively low spinning speeds were subjected to hot drawing. The filaments were characterized by measurements of birefringence, differential scanning calorimetry (DSC) crystallinity, melting point, glass transition temperature, wide‐angle X‐ray diffraction patterns, boiling water shrinkage, tenacity, and elongation to break. Filaments containing 25 mol% MPDiol did not crystallize in the spinline at any spinning speed investigated, whereas the other resins did crystallize in the spinline at high spinning speeds. However, compared with PET homopolymer, increasing substitution of MPDiol reduced the rate at which the crystallinity of the melt spun filaments increased with spinning speed and reduced the ultimate crystallinity that could be achieved by high‐speed spinning. The rate of development of molecular orientation, as measured by birefringence, also decreased somewhat with increasing MPDiol content. Shrinkage in boiling water decreased at high spinning speeds as the amount of crystallinity increased; however, the shrinkage decreased more slowly with increase in spinning speed as MPDiol content increased. Tenacity also decreased slightly at any given spinning speed as MPDiol content increased, but there was no significant effect on elongation to break. The addition of MPDiol in amounts up to 7 mol% increased the maximum take‐up velocity that could be achieved at a given mass throughput. This result indicates that the use of higher spinning speeds could potentially increase the productivity of melt spun yarns. Copolymer filaments spun at low speeds were readily drawn to produce highly oriented fibers with slightly less birefringence, crystallinity, and tenacity than similarly processed PET homopolymer. Preliminary dyeing experiments showed that the incorporation of MPDiol improved the dyeability of the filaments. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2598–2606, 2003
Removal properties of crosslinked poly(2‐acrylamido glycolic acid) for trace heavy metal ions: Effect of pH, temperature, contact time, and salinity on the adsorption behavior
Authors: Rivas Bernabé L. , Quilodrán Benita , Quiroz Eduardo 
Published: March 2003

AbstractCrosslinked poly(2‐acrylamido glycolic acid) resin was synthesized by radical polymerization. This resin contains three potential ligand groups and was studied as an adsorbent of trace heavy metal ions from a saline aqueous solution and sea water by using the Batch equilibrium procedure. Adsorption characteristics of the resin toward Cu(II), Ni(II), Cd(II), and Pb(II) were studied spectrophotometrically, both in competitive and noncompetitive conditions. The effect of pH, contact time, amount of sorbent, temperature, and salinity were studied. The resin showed a high affinity particularly for Ni(II). It was possible to remove completely Ni(II) and Pb(II) from the resin by 4M HNO3. The retention properties of the resin were also investigated for Cu(II) contained in natural sea waters. The retention behavior was similar to that of the synthetic metal ion aqueous solution. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2614–2621, 2003
Evaluation of isocyanate functional groups as a reactive group in the reactive compatibilizer
Authors: Jung Woo‐Chul , Park Kang‐Yeol , Kim Ju‐Young , Suh Kyung‐Do 
Published: March 2003

AbstractReactive compatibilization of an isocyanate (NCO) functional group as a reactive group was investigated. Five kinds of reactive polymers were prepared through solution graft polymerization of low‐density polyethylene (LDPE) copolymerized with acrylic acid (AA), maleic anhydride (MAH), glycidyl methacrylate (GMA), and masked and naked NCO functional monomers and were used as compatibilizers in poly(ethylene terephthalate) (PET)/LDPE and polyamide 6 (Nylon 6)/LDPE blends. The reactivity of the NCO functional group in the reactive blend was evaluated in terms of the blend morphology, adhesive test, mechanical properties, and rheological properties. It was found that GMA and NCO groups were the most effective compatibilizing agents in the PET/LDPE blends and MAH and NCO groups showed effective compatibilization of the Nylon 6/LDPE blends. We confirmed that the NCO functional group as a reactive group could be used as a universal reactive compatibilizer for PET/LDPE and Nylon 6/LDPE blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2622–2629, 2003
Effects of the presence of water on ultrasonic devulcanization of polydimethylsiloxane
Authors: Shim Sang Eun , Isayev A. I. 
Published: March 2003

AbstractThe effects of the presence of water on ultrasonic devulcanization of 30 phr silica‐filled polydimethylsiloxane (PMDS) were investigated at increasing feed rates and different die gap sizes. The results showed that the initial die entrance pressure without ultrasound for wet rubber was higher than in the case without water and then it decreased monotonously with applying ultrasound. The die pressure for wet rubber decreased significantly even at low ultrasonic amplitude, while that for dry rubber changed little at low amplitude. The power consumption at an amplitude of 10 μm, where devulcanization was most effectively achieved, was lower for wet rubber even though the pressure was lower. The crosslink density and gel fraction after the devulcanization of wet rubber were lower than those of dry rubber, indicating that the presence of water facilitates the devulcanization process under the same devulcanization conditions. The good mechanical properties of recycled silica‐filled PDMS were obtained at higher feed rates and at lower ultrasound amplitudes, which are directly related to the economics of a recycling process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2630–2638, 2003
Thermoplastic hydrogel based on pentablock copolymer consisting of poly(γ‐benzyl L‐glutamate) and poloxamer
Authors: Oh Sang‐Bong , Choi Yong‐Kook , Cho Chong‐Su 
Published: March 2003

AbstractA thermoplastic hydrogel based on a pentablock copolymer composed of poly(γ‐benzyl L‐glutamate) (PBLG) and poloxamer was synthesized by polymerization of BLG N‐carboxyanhydride, which was initiated by diamine‐terminated groups located at the ends of poly(ethylene oxide) (PEO) chains of the poloxamer, to attain a new pH‐ and temperature‐sensitive hydrogel for drug delivery systems. Circular dichroism measurements in solution and IR measurements in the solid state revealed that the polypeptide block existed in the α‐helical conformation, as in the PBLG homopolymer. The intensity of the wide‐angle X‐ray diffraction patterns of the polymers depended on the poloxamer content in the copolymer and showed basically similar reflections to the PBLG homopolymer. The melting temperature (Tm) of the poloxamer in the copolymer was reduced with an increase of the PBLG block in comparison with the Tm of the poloxamer, which is indicative of a thermoplastic property. The water contents of the copolymers were dependent on the poloxamer content in the copolymers, for example, those for the GPG‐2 (48.7 mol % poloxamer) and GPG‐1 (57.5 mol % poloxamer) copolymers were 31 and 41 wt %, respectively, indicating characteristics of a polymeric hydrogel. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2649–2656, 2003