bluuebunny/crossref_metadata_2025 huggingface dataset:
Copolymerization of ethylene/propylene elastomer using high‐activity Ziegler–Natta catalyst system of MgCl2 (ethoxide type)/EB/PDMS/TiCl4/PMT
Authors: Zohuri G. H. , Sadegvandi F. , JamJah R. , Ahmadjo S. , Nekoomanesh M. , Bigdelli E.
Published: October 2004

A high‐activity Ziegler–Natta catalyst of TiCl4‐supported MgCl2 (ethoxide type) was prepared. Ethyl benzoate (EB) and polydimethylsiloxane (PDMS) were used as internal donors, while p‐methyl toluate (MPT) and triethylaluminum (TEA) were used as the external donor and cocatalyst, respectively. Suspension copolymerization of ethylene–propylene (EPM) was carried out in n‐heptane using the catalyst system. The relative pressures of 1.5 : 1 and 2 : 1 atmosphere of propylene‐to‐ethylene (PP/PE) gave a polymer with elastomeric properties. The relative pressure of propylene‐to‐ethylene higher and lower than the above values, however, gave a homopolymer or copolymer without elastomeric properties. The effect of the TEA concentration, H2 concentration, temperature, and pressure of PP/PE on the yield of the polymer obtained was investigated. The effects of these factors on the glass transition temperature (Tg) and ethylene content of the polymer were studied. The content of ethylene in EPM was determined using the FTIR technique. The molar ratio of Al : MPT : Ti = 355 : 107 : 1 gave a polymer with an ethylene content of about 32%. However, a ratio lower than AL : MPT : Ti = 355 : 107 : 1 did not give a good elastomeric polymer. The highest productivity of the catalyst was obtained at a molar ratio of AL : MPT : Ti = 355 : 107 : 1. Increasing the temperature from 45 to 70°C caused a slight increase of Et % content and a decrease of the Tg of the copolymer obtained, while the highest productivity of the catalyst was obtained at 55°C with good elastomeric properties using an AL : MPT : Ti = 497 : 107 : 1 molar ratio. Increasing the pressure of propylene from 1.5 to 2.5 atm caused a sharp decrease in the Tg and ethylene content of the polymer. When the ethylene content in the copolymer was increased, the Tg value had a tendency to be closer to the polyethylene Tg. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 785–790, 2002; DOI 10.1002/app.10330
Prediction of the release characteristics of alcohols from EVA using a model based on Fick's second law of diffusion
Authors: Krüger Arnoldus J. , Tolmay Andries T.
Published: October 2004

This study evaluates the use of a simple mathematical model to predict release characteristics of volatile substances from polymer dispensers. The model can be used to simplify the design process of polymer dispensers, which is traditionally done by trial and error. The coefficients of diffusion, D, of four alcohols through EVA disks were determined with the time lag technique. The value of D was used to predict the residual mass of dispensers over time using a model based on Fick's second law of diffusion. Injection‐molded dispensers containing 10% alcohol were prepared, and the release of the alcohol were monitored experimentally. The modeled results were compared to the experimental results. A good correlation was found between the predictions and the experimental results. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 806–813, 2002; DOI 10.1002/app.10333
Effect of processing conditions on the yield and failure response of an aliphatic polyketone terpolymer
Authors: Karttunen Nicole R. , Lesser Alan J.
Published: October 2004

The effect of processing conditions on the yield and failure behavior of an aliphatic polyketone terpolymer was studied. Testing and characterization were performed on samples that were extruded in the form of hollow cylinders. We performed the extrusion process at different shear rates and at different cooling rates to assess the effect that process conditions had on the polymer properties. We performed biaxial testing on the samples to characterize the failure envelopes, including the ductile–brittle transition condition for each process condition. The effect of shear rate was negligible, whereas the cooling rate significantly affected the failure behavior. To explain these differences in behavior, we performed characterization via differential scanning calorimetry, wide‐angle X‐ray diffraction, attenuated total reflection IR spectroscopy, dynamic mechanical thermal analysis, scanning electron microscopy, and residual stress measurements. A broad glass transition was found for all samples at temperatures higher than previously reported for this material. Alteration of the processing conditions did not influence the crystalline phase (percentage crystallinity, crystalline orientation, crystallite size, etc.). A change in spherulitic structure was also observed with altered cooling rate and is suggested to have contributed to the change in failure behavior. Residual stresses also affected the behavior of all samples. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 318–334, 2002; DOI 10.1002/app.10334
Chemical modification of 3,3′,4,4′‐biphenyltetracarboxylic dianhydride polyimides by a catechol‐derived bis(ether amine)
Authors: Yang Chin‐Ping , Hsiao Sheng‐Huei , Chen Ruei‐Shin , Wei Chi‐Shu
Published: October 2004

Having previously demonstrated that the polyimide derived from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA) and 1,2‐bis(4‐aminophenoxy)benzene [termed triphenyl ether catechol diamine (TPEC)] exhibited superior tensile properties in addition to good thermal properties, we now provide a preliminary assessment of the properties of the copolyimides prepared from BPDA, TPEC, and another aromatic diamine. The homopolyimides derived from BPDA and many aromatic diamines generally possessed good mechanical properties and thermal properties; however, they were insoluble in available organic solvents. In several cases, organosoluble BPDA copolyimides could be prepared from BPDA and equimolar mixtures of TPEC and another aromatic diamine. All the copolyimides could be formed into tough films with high moduli and strengths and, in most cases, high extensions to break. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 351–358, 2002; DOI 10.1002/app.10342
Energy‐transfer method to study vapor‐induced latex film formation
Authors: Pekcan Ö. , Adiyaman N. , Uğur Ş.
Published: October 2004

Nonradiative energy transfer method was used to study latex film formation induced by organic solvent vapor. Seven different films with the same latex content were prepared separately from poly(methyl methacrylate) (PMMA) particles and exposed to ethyl benzene, toluene, chloroform, dichloromethane, tetrahydrofuran, and acetone vapor in seven different experiments. Energy‐transfer experiments were carried out between PMMA‐bound naphthalene (N) and pyrene (P) during vapor‐induced film formation. Latex films were prepared from equal amounts of N‐ and P‐labeled latex particles, and steady state spectra of N and P were monitored during film formation. It was observed that the P to N intensity ratio, IP/IN, increased as the vapor exposure time increased. The Prager–Tirrell (PT) model was employed to obtain back‐and‐forth frequencies, ν, of the reptating PMMA chains during latex film formation induced by solvent vapor. ν values were obtained and found to be correlated with the solubility parameter, δ. Polymer interdiffusion obeyed the t1/2 law during film formation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 632–645, 2002; DOI 10.1002/app.10346
Toughening of cycloaliphatic epoxy resins by poly(ethylene phthalate) and related copolyesters
Authors: Iijima Takao , Fujimoto Ken‐Ichiro , Tomoi Masao
Published: October 2004

Poly(ethylene phthalate) (PEP) and poly(ethylene phthalate–co‐ethylene terephthalate) were used to improve the brittleness of the cycloaliphatic epoxy resin 3,4‐epoxycyclohexylmethyl 3,4‐epoxycyclohexane carboxylate (Celoxide 2021™), cured with methyl hexahydrophthalic anhydride. The aromatic polyesters used were soluble in the epoxy resin without solvents and effective as modifiers for toughening the cured epoxy resin. For example, the inclusion of 20 wt % PEP (MW, 7400) led to a 130% increase in the fracture toughness (KIC) of the cured resin with no loss of mechanical and thermal properties. The toughening mechanism is discussed in terms of the morphological and dynamic viscoelastic behaviors of the modified epoxy resin system. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 388–399, 2002; DOI 10.1002/app.10363
Toughening of vinylester–urethane hybrid resins through functionalized polymers
Authors: Gryshchuk O. , Jost N. , Karger‐Kocsis J.
Published: October 2004

Liquid nitrile rubber, hyperbranched polyester, and core/shell rubber particles of various functionality, namely, vinyl, carboxyl, and epoxy, were added up to 20 wt % to a bisphenol‐A‐based vinylester–urethane hybrid (VEUH) resin to improve its toughness. The toughness was characterized by the fracture toughness (Kc) and energy (Gc) determined on compact tensile (CT) specimens at ambient temperature. Toughness improvement in VEUH was mostly achieved when the modifiers reacted with the secondary hydroxyl groups of the bismethacryloxy vinyl ester resin and with the isocyanate of the polyisocyanate compound, instead of participating in the free‐radical crosslinking via styrene copolymerization. Thus, incorporation of carboxyl‐terminated liquid nitrile rubber (CTBN) yielded the highest toughness upgrade with at least a 20 wt % modifier content. It was, however, accompanied by a reduction in both the stiffness and glass transition temperature (Tg) of the VEUH resin. Albeit functionalized (epoxy and vinyl, respectively) hyperbranched polymers were less efficient toughness modifiers than was CTBN, they showed no adverse effect on the stiffness and Tg. Use of core/shell modifiers did not result in toughness improvement. The above changes in the toughness response were traced to the morphology assessed by dynamic mechanical thermal analysis (DMTA) and fractographic inspection of the fracture surface of broken CT specimens. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 672–680, 2002; DOI 10.1002/app.10392
Copolymerization of ethylene/nonconjugated dienes over a Bis(2‐methyl indenyl) zirconium dichloride/methylaluminoxane catalyst system
Authors: Jin Hyoung‐Joon , Choi Chang‐Ho , Park Eun‐Soo , Lee Ik‐Mo , Yoon Jin‐San
Published: October 2004

Ethylene was copolymerized with 1,5‐hexadiene (1,5‐HD), 1,4‐hexadiene (1,4‐HD) and 1,7‐octadiene (1,7‐OD) with bis(2‐methyl indenyl) zirconium dichloride/methylaluminoxane. 1,5‐HD units formed the trans‐structured cyclopentane rings and 1‐butenyl side chains, and cross‐linking took place during ethylene/1,5‐HD (E15HD) copolymerizations. The lower the polymerization temperature was, the larger the amount of hot xylene (XYL)‐insoluble faction was. Copolymers of ethylene/1,7‐OD (E17OD) did not have any cyclic structures and were nearly insoluble in XYL when produced below 60°C. In contrast, all the copolymers of ethylene/1,4‐HD (E14HD) were completely soluble in XYL. The broadest differential scanning calorimetry melting peak was found for E15HD and then for E17OD, and the narrowest was found for E14HD due to the presence or the absence of the cyclic structures and cross‐linking. Addition of 1,7‐OD or 1,4‐HD as a comonomer reduced the polymerization rate and the molecular weight of the respective copolymers much more than that of 1,5‐HD. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1048–1058, 2002; DOI 10.1002/app.10397
Functional, uniform, and macroporous latex particles: Preparation, electron microscopic characterization, and nonspecific protein adsorption properties
Authors: T. Çamli  , Tuncel M. , Şenel S. , Tuncel A.
Published: October 2004

A series of uniform, macroporous particles with different surface chemistries were prepared with different acrylic comonomers [methyl methacrylate (MMA), butyl methacrylate (BMA), epoxypropyl methacrylate (EPMA), 2‐hydroxyethyl methacrylate (HEMA), and methacrylic acid (MAA)] with styrene–divinylbenzene (S–DVB) in a multistep seeded polymerization. In the synthesis, uniform polystyrene seed particles 6.2 μm in size were swollen first with a low molecular weight organic agent and then with a monomer phase including an S–DVB mixture and a relatively polar acrylic monomer. Final macroporous particles approximately 10 μm in size were obtained by the repolymerization of the monomer phase in the swollen seed particles. Surface and bulk morphologies were investigated with scanning and transmission electron microscopy, respectively. Although highly porous particles could be achieved with relatively hydrophobic monomers such as styrene, BMA, MMA, and EPMA, the use of hydrophilic monomers such as HEMA and MAA led to the synthesis of uniform particles with lower macroporosity. A comparison of Fourier transform infrared and Fourier transform infrared/diffuse reflectance spectroscopy spectra indicated that the concentration of polar acrylic monomer on the surface was higher than in the bulk structure. The nonspecific protein adsorption behavior of uniform, macroporous particles was investigated with albumin as a model protein. The highest nonspecific albumin adsorption was observed with plain poly(styrene‐co‐divinylbenzene) [poly(S–DVB)] particles. The particles produced with MMA and EPMA also exhibited albumin adsorption capacities very close to that of plain poly(S–DVB). Reasonably low nonspecific albumin adsorption was observed with the particles produced in the presence of MAA, HEMA, and BMA. Poly(S–DVB) particles functionalized with poly(vinyl alcohol) provided nearly zero nonspecific albumin adsorption. For nonspecific albumin binding onto the particles via a physical adsorption mechanism, desorption ratios higher than 80% could be achieved. The desorption ratio with the EPMA‐carrying particles was only 5% because the albumin adsorption onto EPMA‐carrying particles occurred predominantly with covalent‐bond formation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 414–429, 2002; DOI 10.1002/app.10412
Controlled radical alternating copolymerization of N‐phenyl maleimide with ethyl α‐ethylacrylate by reversible addition fragmentation chain‐transfer process
Authors: Wei Jia , Zhu Zhonglian , Huang Junlian
Published: October 2004

The alternating copolymerization of N‐phenyl maleimide (NPMI) with ethyl α‐ethylacrylate (EEA) by the reversible addition fragmentation chain‐transfer process was investigated. The monomer reactivity ratios were measured and r1 = 0.19 ± 0.03 for NPMI and r2 = 0.20 ± 0.04 for EEA. It was found that before about 45% of the comonomer conversion, the molecular weight of the copolymer increased with the conversion, the molecular weight distribution was rather narrow, and the molecular weight of the copolymer approached a constant value, irrespective of the length of the polymerization time. Electronic spin resonance determined that the radical signal disappeared quickly after the conversion of comonomer exceeded 45%, which may be attributed to the coupling termination of the propagating polymer chains with the EEA end with the intermediate radicals when the concentration of comonomers decreased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2376–2382, 2004
Miscibility and adhesive properties of ethylene vinyl acetate copolymer (EVA)‐based hot‐melt adhesives. I. Adhesive tensile strength
Authors: Takemoto Mototsugu , Kajiyama Mikio , Mizumachi Hiroshi , Takemura Akio , Ono Hirokuni
Published: October 2004

A series of ethylene vinyl acetate copolymers (EVA) were blended with some tackifier resins that are made from wood extracts, and possible relations between their miscibility and properties as hot‐melt adhesives (HMA) were investigated. From our previous report on miscibility of various EVA‐based HMAs, we chose some blends that represent some of typical miscibility types and measured their adhesive tensile strengths. When the blends were miscible at testing temperatures, the temperature at which the maximum value of adhesive tensile strength was recorded tended to move toward higher temperature as tackifier content of blends increased. This result corresponds to the glass transition temperature (Tg) of the blends that became higher as tackifier content of blends increased when blend components were miscible. In terms of HMA performances, we suggest that factors other than miscibility affect absolute values of adhesive tensile strength more directly than miscibility; this idea has to be investigated further in a future study. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 719–725, 2002
Development and characterization of poly(trimethylene terephthalate)‐based bicomponent meltblown nonwovens
Authors: Zhang Dong , Sun Christine , Beard John , Brown Houston , Carson Ian , Hwo Charles
Published: October 2004

Poly(trimethylene terephthalate) (PTT)‐based mono and bico meltblown webs have been produced by using a Reicofil® Bi‐Component Meltblown Line at TANDEC, located at the University of Tennessee, Knoxville, TN. Thermal and flow properties of PTT were first examined by DSC (differential scanning calorimetry) and with a Melt Indexer for an effective experimental design through the Surface Response Methodology (SRM). The processability of meltblowing in a wide range of operating windows was extensively investigated. Melt temperature, melt throughput, air temperature, airflow rate, and DCD (distance of collector to die) were considered as primary process control variables. The produced webs were characterized for fiber diameter, bulk density, air permeability, hydrostatic head, tensile properties, and heat shrinkage. Non‐round and curly or twisted fibers were observed in the bico PP/PTT webs by SEM (scanning electrical microscope). The PTT grade studied is quite suitable for the meltblown process. The PTT/PP‐based bico webs showed enhanced barrier properties and heat resistance. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1280–1287, 2002
Synthesis of 1,4,8,11‐tetraazacyclotetradecane monomer by addition of acryloyl chloride and its polymer for specific transition metal binding
Authors: Salih Bekir
Published: October 2004

1,4,8,11‐Tetraazacyclotetradecane (cyclam) was reacted with acryloyl chloride in a 1 : 2 molar ratio in dichloromethane in the presence of pyridine at 0°C. The modified cyclam was polymerized by adding an azobisisobutyronitrile initiator and irradiated with a UV lamp under reflux for 6 h. Precipitated cyclam containing polymer in the bulk structure was removed from the suspension by filtration. After washing and drying the final polymeric materials were used for transition metal ion adsorption and desorption studies. A Fourier transform IR spectrophotometer and thermogravimetric analyzer were used to characterize the polymeric structure. The affinity of the polymeric material for transition metal ions was used to test the adsorption–desorption of selected ions [Cu(II), Ni(II), Co(II), Cd(II), Pb(II)] from aqueous media containing different amounts of these metal ions (5–800 ppm) at different pH values (2.0–8.0). It was found that the adsorption rates were high and the adsorption equilibrium was reached in about 30 min. The uptake of the transition metal ions onto the polymer from solutions containing a single metal ion was 3.17 mmol/g for Cu(II), 0.98 mmol/g for Cd(II), 0.79 mmol/g for Co(II), 0.78 mmol/g for Ni(II), and 0.32 mmol/g for Pb(II). This polymer showed high affinity for Cu(II) compared to the other metal ions in the single ion solution and in the mixture of transition metal ions. The affinity order of the transition metal ions was Cu(II) ≫ Ni(II) > Cd(II) > Co(II) > Pb(II) for competitive adsorption. More than 95% of the adsorbed transition metal ions were desorbed in 2 h in a desorption medium containing 1.0M HNO3. Poly(cyclam) was found to be suitable for repeated use of more than five cycles without a noticeable loss of adsorption capacity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1406–1414, 2002
Fibers based on cellulose‐chitin blends
Authors: Marsano E. , Conio G. , Martino R. , Turturro A. , Bianchi E.
Published: October 2004

Fibers made of cellulose (CE) and chitin (CH) in different proportion were wet spun from solutions in dimethylacetamide containing 5% LiCl (w/w). Polymer concentration was purposely maintained as low as possible (≅2.4% w/w). Moreover, dope temperature was 60°C to have good spinability. Comparison of the elastic modulus (E) of fibers “as spun” at different CE/CH ratio showed a synergy between the components: at CE/CH ≅ 50/50, E is ≅15 GPa with respect to ≅9 and ≅11 GPa for neat CE and CH fibers, respectively. Application of a pull‐off ratio during the coagulation allows the E value to increase further. These results, as well as the electronic microscopy of fibers section, agree with a complete miscibility of two polymers at the solid state, probably enhanced by the presence of LiCl. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1825–1831, 2002
Analysis of projections from the medial prefrontal cortex to the thalamus in the rat, with emphasis on nucleus reuniens
Authors: Vertes Robert P.
Published: October 2004

The medial prefrontal cortex (mPFC) is involved in high‐order cognitive processes, including, but not limited to, decision making, goal directed behavior, and working memory. Although previous reports have included descriptions of mPFC projections to the thalamus in overall examinations of mPFC projections throughout the brain, no previous study has comprehensively examined mPFC projections to the thalamus. The present report compares and contrasts projections from the four divisions of the mPFC, i.e., the infralimbic, prelimbic, anterior cingulate and medial agranular cortices, to the thalamus in the rat by using the anterograde anatomic tracer Phaseolus vulgaris‐leucoagglutinin. We showed that (1) the infralimbic, prelimbic, anterior cingulate cortices distribute heavily and selectively to midline/medial structures of the thalamus, including the paratenial, paraventricular, interanteromedial, anteromedial, intermediodorsal, mediodorsal, reuniens, and the central medial nuclei; (2) the medial agranular cortex distributes strongly to the rostral intralaminar nuclei (central lateral, paracentral, central medial nuclei) as well as to the ventromedial and ventrolateral nuclei of thalamus; and (3) all four divisions of the mPFC project densely to the nucleus reuniens (RE) of the thalamus. The nucleus reuniens is the major source of thalamic afferents to the hippocampal formation. There are essentially no direct projections from the mPFC to the hippocampus. The present demonstration of pronounced mPFC projections to RE suggests that the nucleus reuniens is a critical relay in the transfer of information from the medial prefrontal cortex to the hippocampus. Our further demonstration of strong mPFC projections to several additional thalamic nuclei, particularly to the mediodorsal nucleus, suggests that these thalamic nuclei, like RE, represent important output stations (or gateways) for the actions of mPFC on diverse subcortical and cortical structures of the brain. J. Comp. Neurol. 442:163–187, 2002. © 2002 Wiley‐Liss, Inc.
Surface modification of an experimental silicone rubber aimed at reducing initial candidal adhesion
Authors: Price C. , Waters M. G. J. , Williams D. W. , Lewis M. A. O. , Stickler D.
Published: October 2004

Silicone rubber, which is a widely used biomaterial, is often used to make soft liners for permanent denture. Colonization of denture soft lining materials by Candida albicans can result in clinical problems. The aim of this study was to chemically modify the surface of an experimental silicone rubber in order to produce a silicone that was less susceptible to candidal colonization. Surface modification was carried out with the use of argon‐plasma bombardment followed by silane treatment, which caused the incorporation of either hydrophilic or hydrophobic functional groups onto the surface. Changes in water contact angles and chemical analysis of the materials with scanning ion mass spectroscopy confirmed surface changes. In vitro assays were carried out using C. albicans to measure levels of adherence to the surface‐modified silicone after 1 h. C. albicans exhibited very low adherence to all silane‐treated surfaces, whether hydrophobic or hydrophilic. This led to the conclusion that incorporated long‐chain functional groups were inhibiting the adherence of the yeast, possibly by the formation of a barrier between the surface of the material and the yeast. In conclusion, silane surface treatment of an experimental silicone rubber has been successful in reducing candidal adherence. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 122–128, 2002; DOI 10.1002/jbm.10094
Effects of low‐intensity pulsed ultrasound on proliferation and chondroitin sulfate synthesis of cultured chondrocytes embedded in Atelocollagen® gel
Authors: Nishikori T. , Ochi M. , Uchio Y. , Maniwa S. , Kataoka H. , Kawasaki K. , Katsube K. , Kuriwaka M.
Published: October 2004

The effects of low‐intensity pulsed ultrasound (US) on the proliferation and chondroitin sulfate synthesis of cultured chondrocytes embedded in Atelocollagen® gelin vitrowere examined. Articular cartilage was harvested from the hip, knee, and shoulder joints of 10‐week‐old Japanese white rabbits. Chondrocytes isolated by collagenase digestion were embedded in type I collagen gel, Atelocollagen gel, and were cultured in Dulbecco's modified eagle's medium for 3 weeks. The US apparatus, SAFHS® , was used to deliver an ultrasound signal with spatial and temporal average intensities of 30 mW/cm2(US group). The frequency was 1.5 MHz with a 200‐microsecond tone burst repeated at 1.0 kHz. US treatments were administered for 20 min per day under culture dishes, with the medium replaced twice a week. Another group of cells was exposed to sham ultrasound as a control. Cell number, histological findings, synthesis of isomers of chondroitin sulfate, and stiffness of the chondrocyte–collagen gel composites were analyzed. US exposure promoted synthesis of chondroitin sulfate, especially chondroitin 6‐sulfate, although it did not significantly enhance cell number and stiffness. In this three‐dimensional culture model, these results suggest that US exposure may be clinically useful in improving the quality of chondrocyte–Atelocollagen implants for transplantation into articular cartilage defects. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 201–206, 2002
Bone response to radio frequency sputtered calcium phosphate implants and titanium implants in vivo
Authors: Ong J. L. , Bessho K. , Cavin R. , Carnes D. L.
Published: October 2004

The objective of this study was to evaluate the effect of radio frequency sputtered calcium phosphate (CaP) coatings of titanium (Ti) implants on the bond strength at the bone–implant interface and percent bone contact length. Cylindrical coated or noncoated implants (4.0‐mm diameter by 8‐mm long) were implanted for 3 and 12 weeks. At 3 weeks after implant placement, the ultimate interfacial strengths for as‐deposited CaP‐coated and heat‐treated CaP‐coated implants were 2.29 ± 0.14 MPa and 1.28 ± 0.04 MPa, respectively. These ultimate interfacial strength values at 3 weeks were statistically greater than the mean ultimate interfacial strength for control Ti implants (0.67 ± 0.13 MPa). At 12 weeks after implant placement, no statistical differences in the mean ultimate interfacial strengths were observed between the as‐deposited CaP‐coated, heat‐treated CaP‐coated, and control Ti implants. Histomorphometric evaluation indicated greater percent bone contact lengths for the as‐deposited CaP‐coated implants compared with the heat‐treated CaP‐coated and control Ti implants 3 and 12 weeks after implant placement. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 184–190, 2002
From theory to practice: School leaders' perspectives on resiliency
Authors: Bosworth Kris , Earthman Erik
Published: October 2004

Resiliency describes the ability of children to overcome adversity and become successful adults. School‐based programs, strategies, or policies designed to enhance resiliency are relatively new. School administrators (n= 10) who had attended an informational meeting about a community‐wide resiliency initiative were interviewed about their understanding of resiliency and their present and future plans to implement resiliency initiatives in their schools. Interviewees provided various definitions of resiliency, ranging from a relatively narrow focus on individual characteristics to a broad focus on various environmental factors. Only those administrators who uniformly held the belief that resiliency was an environmental phenomenon that could be promoted in a school setting decided to participate in the community‐wide initiative. However, the concept of resiliency has captured the imagination of these school administrators and is seen as a relevant organizing point for designing school programs and school environments. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 299–306, 2002.
Sonographic features of polyorchidism
Authors: Chung Ta‐Jung , Yao Wei‐Jen
Published: October 2004

We describe a case of polyorchidism diagnosed sonographically. Palpation revealed a nontender oval mass, about 1 cm large, inferior to the left testis. Sonography identified the mass as an accessory testis that measured 1.0 × 0.8 × 0.6 cm and had its own epididymis. The echotexture in the accessory testis was similar to that in the normal testes, and color Doppler sonography demonstrated that it had normal blood supply. MRI confirmed these findings. High‐resolution sonography is an effective, noninvasive means of accurately diagnosing polyorchidism without the need for exploratory surgery. © 2002 John Wiley & Sons, Inc. J Clin Ultrasound 30:106–108, 2002; DOI 10.1002/jcu.10031
Sonographic assessment of blunt abdominal trauma: A 4‐year prospective study
Authors: Richards John R. , Schleper Nicole H. , Woo Brian D. , Bohnen Paul A. , McGahan John P.
Published: October 2004

Purpose

Emergency abdominal sonography has become a common modality worldwide in the evaluation of injuries caused by blunt trauma. The sensitivity of sonography in the detection of hemoperitoneum varies, and little is known about the accuracy of sonography in the detection of injuries to specific organs. The purpose of this study was to determine the overall accuracy of sonography in the detection of hemoperitoneum and solid‐organ injury caused by blunt trauma.

Methods

From January 1995 to October 1998, 3,264 patients underwent emergency sonography at our institution to evaluate for free fluid and parenchymal abnormalities of specific organs caused by blunt trauma. All patients with intra‐abdominal injuries (IAIs) were identified, and their sonographic findings were compared with their CT and operative findings, as well as their clinical outcomes.

Results

Three hundred ninety‐six (12%) of the 3,264 patients had IAIs. Sonography detected free fluid presumed to represent hemoperitoneum in 288 patients (9%). The sonographic detection of free fluid alone had a 60% sensitivity, 98% specificity, 82% positive predictive value, and 95% negative predictive value for diagnosing IAI. The accuracy was 94%. Seventy patients (2%) had parenchymal abnormalities identified with sonography that corresponded to actual organ injuries. The sensitivity of the sonographic detection of free fluid and/or parenchymal abnormalities in diagnosing IAI was 67%.

Conclusions

Emergency sonography to evaluate patients for injury caused by blunt trauma is highly accurate and specific. The sonographic detection of free fluid is only moderately sensitive for diagnosing IAI, but the combination of free fluid and/or a parenchymal abnormality is more sensitive. © 2002 John Wiley & Sons, Inc. J Clin Ultrasound 30:59–67, 2002; DOI 10.1002/jcu.10033
Can the apparent diffusion coefficient be used as a noninvasive parameter to distinguish tumor tissue from peritumoral tissue in cerebral gliomas?
Authors: Pauleit Dirk , Langen Karl‐Josef , Floeth Frank , Hautzel Hubertus , Riemenschneider Markus J. , Reifenberger Guido , Shah N. Jon , Müller Hans‐Wilhelm
Published: October 2004

Purpose

To determine whether the apparent diffusion coefficient (ADC) can be used to distinguish between tumor tissue and peritumoral brain tissue in cerebral gliomas.

Materials and Methods

Twenty‐two patients with 44 biopsies were enrolled in this study. ADC maps calculated from a diffusion‐weighted (DW) multislice EPI sequence were coregistered with conventional MR images. Neuronavigated biopsies and intraoperative markers were used for correlation with the histologic specimens. ADC values and lesion‐to‐brain ratios of the different sequences were calculated and compared for tumor tissue and peritumoral brain tissue. A logistic regression analysis was performed to determine the diagnostic value of the ADC maps.

Results

The ADC values and ratios demonstrated a large overlap between tumor tissue and peritumoral tissue. Group comparisons revealed a significantly (P = 0.03) lower ADC ratio in tumor tissue (mean = 1.28 ± 0.39) compared to peritumoral tissue (mean = 1.48 ± 0.30), whereas the absolute ADC values did not differ significantly. In the logistic regression analysis, the lesion‐to‐brain ratio of the gadolinium (Gd)‐enhanced T1‐weighted sequence was the most valuable predictor of the presence of tumor tissue. The ADC value and ratio were not identified as significant predictors.

Conclusion

The ADC is not helpful for distinguishing tumor tissue from peritumoral brain tissue in gliomas. J. Magn. Reson. Imaging 2004;20:758–764. © 2004 Wiley‐Liss, Inc.
Phylogenetic analysis indicates transmission of hepatitis C virus from an infected orthopedic surgeon to a patient
Authors: Ross R. Stefan , Viazov Sergei , Roggendorf Michael
Published: October 2004

During recent years, a controversial discussion has emerged in the medical community on the real number and possible public health implications of hepatitis C virus (HCV) transmissions from infected medical staff to susceptible patients. We report here on molecular virological and epidemiological analyses involving 229 patients who underwent exposure‐prone operations by an HCV‐infected orthopedic surgeon. Of the 229 individuals affected, 207 could be tested. Three were positive for HCV antibodies. Molecular and epidemiological investigation revealed that two of them were not infected by the surgeon. The third patient, a 50‐year‐old man, underwent complicated total hip arthroplasty with trochanteric osteotomy. He harbored an HCV 2b isolate that in phylogenetic analysis of the hypervariable region 1 (HVR 1) was closely related to the HCV strain recovered from the infected surgeon, indicating that HCV‐provider‐to‐patient transmission occurred intraoperatively. To our knowledge, this is the first documented case of HCV transmission by an orthopedic surgeon. The recorded transmission rate of 0.48% (95% confidence interval: 0.09–2.68%) was within the same range reported previously for the spread of hepatitis B virus during orthopedic procedures. Since the result of our investigation sustains the notion that patients may contract HCV from infected health‐care workers during exposure‐prone procedures, a series of further retrospective exercises is needed to assess more precisely the risk of HCV provider‐to‐patient transmission and to delineate from these studies recommendations for the guidance and management of HCV‐infected medical personnel. J. Med. Virol. 66:461–467, 2002. © 2002 Wiley‐Liss, Inc.
Early and late morbidity associated with axillary levels I–III dissection in breast cancer
Authors: Ernst Miranda F. , Voogd Adri C. , Balder Willemijn , Klinkenbijl Jean H. G. , Roukema Jan A.
Published: October 2004

Background and Objectives

Axillary dissection may cause substatial morbidity in breast cancer patients. The purpose of this study was to investigate the value of a registration method of morbidity of the arm and shoulder, which is frequently used by surgeons and which includes the measurement of range of movement, strength, and pain.

Methods

We surveyed 148 patients who had received an axillary dissection as part of breast cancer surgery. Of these patients, 77 had undergone axillary dissection 6–12 months ago and 71 patients more than 5 years ago. In all patients, an objective measurement of shoulder movement and a subjective measurement of pain and arm strength was performed.

Results

A difference of more than 20 degrees in abduction, ventral elevation, or dorsal elevation occurred in 12% of the patients. Pain or loss of strength were measured in half of the patients. Shoulder movement, pain, and arm strength were not significantly different between the patients who underwent mastectomy or breast conserving surgery. Also, no significant difference could be found in shoulder movement, pain, and arm strength between the patients who underwent axillary dissection 6–12 months ago and those who underwent it more than 5 years ago.

Conclusions

Pain, loss of arm strength, and limitation of shoulder movement are frequent complaints after axillary dissection for breast cancer and appear to be independent of the length of follow‐up and the type of surgery (i.e., breast‐conservation or mastectomy). J. Surg. Oncol. 2002;79:151–155. © 2002 Wiley–Liss, Inc.
Use of microsatellite analysis in young patients with colorectal cancer to identify those with hereditary nonpolyposis colorectal cancer
Authors: Ikenaga Masakazu , Tomita Naohiro , Sekimoto Mitsugu , Ohue Masayuki , Yamamoto Hirofumi , Miyake Yasuhiro , Mishima Hideyuki , Nishisho Isamu , Kikkawa Nobuteru , Monden Morito
Published: October 2004

Background and Objectives

The frequency of microsatellite instability (MSI) in young patients with colorectal cancer was evaluated, including reexamination of the medical and family history of each patient, and interviews with the patients to determine any possible new occurrence of hereditary nonpolyposis colorectal cancer (HNPCC) in the patients themselves or their family members.

Methods

Fifty‐three young patients (younger than 40 years of age) with colorectal cancer were selected and investigated. DNA was extracted from paraffin sections and microsatellite analysis was performed.

Results

The frequency of MSI among the young patients with colorectal cancer was 50.9%, which was significantly higher than the rate of 12–21% noted in older patients with colorectal cancer (P < 0.001). For the 24 young patients with colorectal cancer who did not have MSI, only one case of HNPCC kindred and two cases with a family history of cancer were identified. In contrast, among the 20 young patients with colorectal cancer who had MSI, five cases of HNPCC kindred, two cases with metachronous patients with colorectal cancer, and three cases with a family history of cancer were identified.

Conclusion

Our results suggest that a defect in the DNA mismatch repair system may play some role in carcinogenesis in young patients with colorectal cancer. Microsatellite analysis and subsequent interviews regarding medical and family history are useful tools for efficiently identifying possible cases of HNPCC among young patients with colorectal cancer. J. Surg. Oncol. 2002;79:157–165. © 2002 Wiley–Liss, Inc.
Cellular manifestations of human papillomavirus infection in laryngeal tissues
Authors: Jacob Sajini Elizabeth , Sreevidya S. , Chacko Elizabeth , Pillai M. Radhakrishna
Published: October 2004

Background and Objectives

Although epidemiologic studies have suggested human papillomavirus (HPV) to be an etiological agent in laryngeal carcinogenesis, little is known on the cellular manifestations of HPV infection in these tumors. In this study, we investigated the frequency of HPV infection in various neoplastic and non‐neoplastic laryngeal tissue and its association with expression of the proliferating cell nuclear antigen (PCNA) and the tumor suppressor protein p53.

Methods

Tissues were analyzed by polymerase chain reaction (PCR) for the presence of HPV and by immunocytochemistry for the expression of p53 and PCNA.

Results

None of the six normal laryngeal tissues showed the presence of HPV. Thirteen out of the 16 papillomas were positive for HPV, while 15 out of the 44 invasive cancers were HPV positive. PCNA expression increased as the lesion progressed through increasing histological abnormality (r = 0.64400, P = 0.00000). The correlation between the type of laryngeal neoplasm and p53 accumulation was significant (r = 0.54839, P = 0.00000). Significant correlation was also evident between presence of HPV and p53 accumulation (r = 0.34259, P = 0.00424) and PCNA expression (r = 0.036024, P = 0.00266) indicating that HPV positive tumors showed significant p53 accumulation and increased proliferation.There was also correlation between p53 and PCNA expression (r = 0.67475, P = 0.00000) indicating that in all tumors with p53 accumulation, there was a corresponding increase in PCNA expression.

Conclusions

The results suggests that changes in p53 and PCNA expression may be associated with HPV infection, and could play a role in laryngeal carcinogenesis. J. Surg. Oncol. 2002;79:142–150. © 2002 Wiley–Liss, Inc.
A compact dual‐interleaved printed antenna
Authors: Kan H. K. , Pavlickovski D. , Waterhouse R. B.
Published: October 2004

A novel, compact dual‐interleaved printed antenna is presented. The antenna consists of two interleaved L‐shaped shorted patches with the required feed network etched on a high‐dielectric‐constant substrate located below the ground plane of the antenna. A 10‐dB return loss impedance bandwidth of 16.9% has been achieved. The overall size of the proposed antenna is 0.2λ0 × 0.15λ0 × 0.10λ0. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 501–503, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20515
Value of surveillance imaging in the management of medulloblastoma
Authors: Yalçın Bilgehan , Büyükpamukçu Münevver , Akalan Nejat , Cila Ayşenur , Kutluk M. Tezer , Akyüz Canan
Published: October 2004

Background

To investigate the value of surveillance scanning for the detection of recurrences in medulloblastoma.

Procedure

The charts of 95 patients with medulloblastoma were retrospectively reviewed. Information regarding the patient characteristics, treatment modalities, dates, types and results of CT and MRI studies, the frequency with which recurrences were identified on surveillance images, changes in patient management, outcome of the patients following recurrences, and survival data were analyzed.

Results

Thirty‐one patients had a recurrence of tumor in the central nervous system; none experienced extraneural relapses. Of all recurrences, 21 were symptomatic and 10 were discovered by surveillance scans asymptomatically. None of the patients with a recurrence survived. For all 95 patients, 5‐year overall and event‐free survival rates were 47.1 and 49.8%, respectively. In patients with symptomatic and asymptomatic recurrences, the mean time to recurrence since initial diagnosis, the mean duration of survival post‐recurrence, and the mean duration of overall follow‐up were 19.2 and 26.1 months, 3.6 and 8.0 months, and 22.8 and 34.1 months, respectively. For 95 patients, 468 surveillance and 38 symptomatic images were reviewed as 313 CTs and 193 MRIs. Rate of diagnosis of recurrence per surveillance image was 2.1% (10/468).

Conclusions

In our study, surveillance scanning brought no survival advantage since it detected a minority of recurrences. Longer survival achieved by early detection of recurrences might be a reflection of lead‐time and length biases. Surveillance procedures will gain more importance as new effective therapeutic options are developed for recurrent medulloblastoma. Med Pediatr Oncol 2002;38:91–97. © 2002 Wiley‐Liss, Inc.
Prognostic impact of molecular genetic alterations in hepatoblastoma
Authors: von Schweinitz Dietrich , Kraus Jürgen A. , Albrecht Steffen , Koch Arend , Fuchs Jörg , Pietsch Torsten
Published: October 2004

Background

During recent years, we identified characteristic genetic alterations in sporadic hepatoblastoma (HB). These include loss of heterozygosity (LOH) at the chromosomal region 11p15.5, LOH on chromosome arms 1p and 1q, activating mutations in exon 3 of the β‐catenin gene, as well as overexpression of the c‐met oncogene, which encodes the hepatocyte growth factor receptor. We now wanted to evaluate the prognostic relevance of these abnormalities concerning the outcome in a large group of patients.

Procedure

All but 7 of 56 patients with HB were treated either with primary resection for small tumors, or neo‐adjuvant chemotherapy with ifosfamide, cisplatin and doxorubicin (IPA) before delayed surgery in case of extended disease and additional adjuvant IPA therapy in all cases. Seven tumors were primarily resected and adjuvantly treated with different cytotoxic drugs. LOH 11p15.5, LOH 1p, and LOH 1q were detected in tumor tissue in comparison to normal liver and/or peripheral blood leukocytes by PCR based microsatellite analysis. Beta‐catenin mutations were analysed with SSCP, deletion screening and direct sequencing. RT‐PCR was used for identification of c‐met mRNA overexpression. The results were correlated with the tumors' stage, histological type and epithelial differentiation, as well as with the patients' outcome.

Results

Overall disease‐free survival after median follow‐up of 5 years was 43/56 patients (77%). LOH 11p15.5 was found in 15/56, LOH1p in 11/53, LOH1q in 7/53 and β‐catenin mutations in 25/55 HB. 13/23 HB had a c‐met overexpression. LOH 11p15.5 and LOH 1p were significantly more often found in embryonal HB, while there was no correlation of other genetic alterations with histological type or differentiation. Furthermore, statistical analysis revealed no correlation of any of these disorders with initial tumor stage, nor with the patients' outcome.

Conclusion

None of the investigated molecular genetic alterations are suited to serve as a prognostic indicator in HB. Further investigations, especially genetic screening of tumor tissue may reveal prognostic markers for this neoplasm. Med Pediatr Oncol 2002;38:104–108. © 2002 Wiley‐Liss, Inc.
New cyclooxygenase‐2 inhibitors for treatment of experimental autoimmune neuritis
Authors: Miyamoto Katsuichi , Oka Nobuyuki , Kawasaki Teruaki , Miyake Sachiko , Yamamura Takashi , Akiguchi Ichiro
Published: October 2004

We analyzed two new cyclooxygenase‐2 (COX‐2) inhibitors, celecoxib (SC‐58635) and meloxicam, for the treatment of experimental autoimmune neuritis (EAN) in rats. Celecoxib and meloxicam significantly reduced clinical EAN score and histopathological damage of the sciatic nerve. They induced no serious side effects, whereas indomethacin used as a control caused severe intestinal ulceration and dysfunction of liver and kidney. These findings suggest that the new COX‐2 inhibitors may be useful as additional therapeutic agents for patients with Guillain–Barré syndrome and chronic inflammatory demyelinating polyneuropathy. © 2002 John Wiley & Sons, Inc. Muscle Nerve 25: 280–282, 2002 DOI 10.1002/mus.10019
Running endurance abnormality in mdx mice
Authors: Hara Hajime , Nolan Patrick M. , Scott Marion O. , Bucan Maja , Wakayama Yoshihiro , Fischbeck Kenneth H.
Published: October 2004

The mdx mouse lacks dystrophin and has histological features of Duchenne muscular dystrophy but little weakness in the first year of life. We report here an early deficit in voluntary wheel running, as assayed with a computerized wheel. All mdx mice showed an intermittent running pattern, in contrast to the continuous running seen in controls. The average continuous running time differed significantly between mdx and control mice at all ages tested (5–21 weeks). This assay is noninvasive, has the advantage of unbiased automatic data collection, and should be useful for quantifying the mdx deficit in therapeutic studies. © 2002 John Wiley & Sons, Inc. Muscle Nerve 25: 207–211, 2002 DOI 10.1002/mus.10021