bluuebunny/crossref_metadata_2025 huggingface dataset:
Loss of phosphatase activity in Ptp69D alleles supporting axon guidance defects
Authors: Marlo Joy E. , Desai Chand J.
Published: March 2006

PTP69D is a receptor protein tyrosine phosphatase that was identified as a key regulator of neuromuscular axon guidance in Drosophila, and has subsequently been shown to play a similar role in the central nervous system and retina. Three Ptp69D alleles with mutations involving catalytically important residues exhibit a high degree of phenotypic variation with viability of mutant adult flies ranging from 0 to 96%, and ISNb motor nerve defects ranging from 11 to 57% [Desai and Purdy, 2003]. To determine whether mutations in Ptp69D affecting axon guidance and viability demonstrate losses of phosphatase activity and whether differences in catalytic potential underlie phenotypic variability, we expressed full‐length wild‐type and mutant PTP69D protein in Schneider 2 cells, and assessed phosphatase activity using the fluorogenic substrate 6,8‐difluoro‐4‐methylumbelliferone phosphate (DiFMUP). Detailed biochemical characterization of wild‐type PTP69D, including an examination of sensitivity to various inhibitors, in vitro catalytic efficiency, and the pH‐kcat profile of the enzyme, suggests a common tyrosine phosphatase reaction mechanism despite lack of sequence conservation in the WPD loop. Analysis of mutant proteins revealed that every mutant had less than 1% activity relative to the wild‐type enzyme, and these rates did not differ significantly from one another. These results indicate that mutations in Ptp69D resulting in axon guidance defects and lethality significantly compromise catalytic activity, yet the range of biological activity exhibited by Ptp69D mutants cannot be explained by differences in catalytic activity, as gauged by their ability to hydrolyze the substrate DiFMUP. J. Cell. Biochem. 98: 1296–1307, 2006. © 2006 Wiley‐Liss, Inc.
Fluid flow induces Rankl expression in primary murine calvarial osteoblasts
Authors: Mehrotra Meenal , Saegusa Masatomo , Wadhwa Sunil , Voznesensky Olga , Peterson Donald , Pilbeam Carol
Published: March 2006

Mechanical loading of bone generates fluid flow within the mineralized matrix that exerts fluid shear stress (FSS) on cells. We examined effects of FSS on receptor activator of nuclear factor κ B ligand (RANKL), a critical factor for osteoclast formation. Primary murine osteoblasts were subjected to pulsatile FSS (5 Hz, 10 dynes/cm2) for 1 h and then returned to static culture for varying times (post‐FSS). Protein levels were measured by Western analysis and mRNA by Northern analysis, RT‐PCR and quantitative PCR. There were 20‐ to 40‐fold increases in RANKL mRNA at 2–4 h post‐FSS. RANKL protein was induced by 2 h post‐FSS and remained elevated for at least 8 h. Effects were independent of cyclooxygenase‐2 activity. Small increases (up to three‐fold) in mRNA of the decoy receptor for RANKL, osteoprotegerin, were seen. Five min of FSS, followed by static culture, was as effective in stimulating RANKL mRNA as 4 h of continuous FSS. FSS induced cAMP activity, and H‐89, a protein kinase A (PKA) inhibitor, blocked the FSS induction of RANKL. H‐89 also inhibited the PKC pathway, but specific PKC inhibitors, GF109203X and Go6983, did not inhibit FSS‐induced RANKL. FSS induced phosphorylation of ERK1/2, and PD98059, an inhibitor of the ERK pathway, inhibited the FSS induction of RANKL mRNA 60%–90%. Thus, brief exposure to FSS resulted in sustained induction of RANKL expression after stopping FSS, and this induction was dependent on PKA and ERK signaling pathways. Increased RANKL after mechanical loading may play a role in initiating bone remodeling. J. Cell. Biochem. 98: 1271–1283, 2006. © 2006 Wiley‐Liss, Inc.
Doping effects on proton incorporation and conduction in SrZrO3
Authors: Shi Chunsheng , Morinaga Masahiko
Published: March 2006

The doping effects on the proton incorporation and protonic conductivity of perovskite‐type SrZrO3 were investigated using the density functional theory (DFT) with the generalized gradient approximation (GGA). The optimized geometries, formation energies of hydrogen defect and activation energies for hydrogen diffusion in SrZrO3 doped with Al, Sc, Ga, Y, Rh, In, and Yb were calculated. It was shown that the doping leads to large local distortions around hydrogen and dopant ion, affecting the protonic conduction in these oxides. The alignment of hydrogen levels varies with the dopant introduced into the SrZrO3. In In‐, Y‐, Sc‐, Ga‐, and Al‐doped SrZrO3, the H+ is the lowest energy state in all the bandgap. But for Yb‐ and Rh‐doped SrZrO3, the H+ is the lowest energy state only when the Fermi energy below 2.37 and 2.66 eV, respectively. The estimates of the activation energy show good agreement between the measured and calculated activation energies. Also, the hydrogen diffusion seems to become more difficult as the distance between hydrogen and dopant ion decreases. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 711–718, 2006
Allostery of the two‐state model of hemoglobin studied by ECEPP energy minimization
Authors: Seno Yasunobu
Published: March 2006

Recently, a powerful parallel‐vector processor became available for molecular science. A new FORTRUN program was coded to treat the whole hemoglobin molecule with twofold symmetry. Using the X‐ray coordinates of deoxyhemoglobin and oxyhemoglobin, minimum energy conformations were obtained for both the T‐state and the R‐state on the two‐state model of allostery. From them, further energy minimization was performed with simple perturbation to bring the proximal region close to the heme group instead of oxygen binding, and the structural changes and energy changes were investigated. The difference of calculated energy changes between T and R was semiquantitatively in agreement with the experimental value 2.7 kcal/mol for one oxygen binding. When the perturbation was exerted on the α‐subunits, the energy change within the perturbed α‐subunits in the T‐state gave a main contribution, and in the R‐state, the structural changes of the α‐subunits were specifically large. When the perturbation was exerted on the β‐subunits, the intersubunit interaction energy between α1 and β2 (α2 and β1) was dominant in the difference of the energy changes between T and R. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 701–710, 2006
Direct constructions for cyclically relative difference matrices with five rows
Authors: Ding Cunsheng , Yin Jianxing
Published: March 2006

In this article, we construct a (6p, 5, 1) cyclic difference matrix with one hole of size 6 for any prime p > 5 and a (2p, 5, 1) cyclic difference matrix with one hole of size 2 for any prime p ≡ 1, 13 or 17 (mod 24). © 2006 Wiley Periodicals, Inc. J Combin Designs 14: 391–399, 2006
Small latin squares, quasigroups, and loops
Authors: McKay Brendan D. , Meynert Alison , Myrvold Wendy
Published: March 2006

We present the numbers of isotopy classes and main classes of Latin squares, and the numbers of isomorphism classes of quasigroups and loops, up to order 10. The best previous results were for Latin squares of order 8 (Kolesova, Lam, and Thiel,1990), quasigroups of order 6 (Bower,2000), and loops of order 7 (Brant and Mullen,1985). The loops of order 8 have been independently found by “QSCGZ” and Guérin (unpublished,2001).

We also report on the most extensive search so far for a triple of mutually orthogonal Latin squares (MOLS) of order 10. Our computations show that any such triple must have only squares with trivial symmetry groups. © 2006 Wiley Periodicals, Inc. J Combin Designs
Quasi‐symmetric designs with fixed difference of block intersection numbers
Authors: Pawale Rajendra M.
Published: March 2006

The following results for proper quasi‐symmetric designs with non‐zero intersection numbers x,y and λ > 1 are proved.

Let D be a quasi‐symmetric design with z = y − x and v ≥ 2k. If x ≥ 1 + z + z3 then λ < x + 1 + z + z3.

Let D be a quasi‐symmetric design with intersection numbers x, y and y − x = 1. Then D is a design with parameters v = (1 + m) (2 + m)/2, b = (2 + m) (3 + m)/2, r = m + 3, k = m + 1, λ = 2, x = 1, y = 2 and m = 2,3,… or complement of one of these design or D is a design with parameters v = 5, b = 10, r = 6, k = 3, λ = 3, and x = 1, y = 2.

Let D be a triangle free quasi‐symmetric design with z = y − x and v ≥ 2k, then x ≤ z + z2.

For fixed z ≥ 1 there exist finitely many triangle free quasi‐symmetric designs non‐zero intersection numbers x, y = x + z.

There do not exist triangle free quasi‐symmetric designs with non‐zero intersection numbers x, y = x + 2.

© 2006 Wiley Periodicals, Inc. J Combin Designs 15: 49–60, 2007
Radiological and pathological changes in hemiballism‐hemichorea with striatal hyperintensity
Authors: Nath Jaya , Jambhekar Kedar , Rao Chandrakanth , Armitano Erik
Published: March 2006

We report CT and MRI findings in a 50‐year‐old African‐American woman with hemichorea‐hemiballism (HCHB) and hyperglycemia with striatal hyperintensity. Histopathologic findings following autopsy are also described, and possible explanations for the MR findings of this unique syndrome are presented. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Why lateral meniscectomy is more dangerous than medial meniscectomy. A finite element study
Authors: Peña Estefania , Calvo Begoña , Martinez Miguel Angel , Palanca Daniel , Doblaré Manuel
Published: March 2006

Total meniscectomies are commonly thought to cause progressive degenerative arthrosis pathology in articular cartilage in a period of a few years because of alteration of the biomechanical environment including increased joint instability. This concern has lead to a preference for partial meniscectomies, although lateral partial meniscectomies sometimes lead to catastrophic results. We performed a three‐dimensional finite element model of the human tibiofemoral joint to examine the effect of lateral meniscectomy on knee biomechanics. The results were compared to those from modeling a medial meniscectomy. Under axial femoral compressive loads, the peak contact stress and maximum shear stress in the articular cartilage increased 200% more after a lateral than a medial meniscectomy. These increased stresses could partly explain the higher cartilage degeneration observed after a lateral meniscectomy. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
High‐dose gamma irradiation for soft tissue allografts: High margin of safety with biomechanical integrity
Authors: Grieb Teri A. , Forng Ren‐Yo , Bogdansky Simon , Ronholdt Chad , Parks Brent , Drohan William N. , Burgess Wilson H. , Lin Jack
Published: March 2006

Screening and processing methods currently in place have made the risk of bacterial and viral infections from allograft tissues extremely low. However, the development of a terminal sterilization method that does not adversely affect tissue function would provide an added safety to tissues for transplantation. We assessed whether high‐dose gamma irradiation could be used as an effective terminal sterilization method for allografts without impairing the preimplantation mechanical integrity of the tissues. Semitendinosus tendons were pretreated with a radioprotectant solution and then irradiated to 50 kGy under well‐defined conditions that included a tight dose range and maintained low temperatures. Maximum force, strain, stress, modulus, and strain energy density for tendons irradiated to 50 kGy were compared to nonirradiated control tendons and tendons irradiated to 18 kGy by a commercial tissue bank using their existing method. The preimplantation biomechanical properties of the 50‐kGy group compared favorably to the nonirradiated and 18 kGy groups. A study to evaluate the postimplantation mechanical and biological performance of grafts irradiated to 50 kGy is ongoing. Pathogen inactivation was also quantified following 50 kGy of irradiation, with ≥4.5 logs of Sindbis virus and 4.9 logs of parvovirus kill achieved. Analysis of Clostridium sordellii inactivation kinetics indicated that a 16 log10 reduction is predicted with 50 kGy of irradiation. A high dose of gamma irradiation using the described conditions can reduce infectious risks associated with soft tissue allografts while maintaining the preimplantation biomechanical performance of the tissues. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Early healing of flexor tendon insertion site injuries: Tunnel repair is mechanically and histologically inferior to surface repair in a canine model
Authors: Silva Matthew J. , Thomopoulos Stavros , Kusano Nozomu , Zaegel Melissa A. , Harwood Frederick L. , Matsuzaki Hironori , Havlioglu Necat , Dovan Thomas T. , Amiel David , Gelberman Richard H.
Published: March 2006

Orthopedic injuries often require surgical reattachment of tendon to bone. Tendon ends can be sutured to bone by direct apposition to the bone surface or by placement within a bone tunnel. Our objective was to compare early healing of a traditional surface versus a novel tunnel method for repair of the flexor digitorum profundus (FDP) tendon insertion site in a canine model. A total of 70 tendon–bone specimens were analyzed 0, 5, 10 or 21 days after injury and repair, using tensile and range of motion mechanical testing, histology and densitometry. Ultimate force (a measure of repair strength) did not differ between surface and tunnel repairs at day 0. Both repair types had reduced strength at 10 and 21 days compared to 0 days, indicative of deterioration of suture grasping strength (tendon softening). At 21 days, tendons repaired in a bone tunnel had 38% lower ultimate force compared to surface repairs (p = 0.017). Histological findings were comparable between repair groups at 5 and 10 days but differed at 21 days, when we saw evidence of maturation of the tendon–bone interface in the surface repairs compared to an immature fibrous interface with no evidence of tendon–bone integration in the tunnel repairs. After accounting for bone removed by the tunnel, no difference in bone mineral density or trabecular bone volume existed between surface and tunnel repairs. If the results of our animal study extend to healing of the human FDP insertion, they indicate that FDP tendons should be reattached to the distal phalanx by suture to the cortical surface rather than suture in a bone tunnel. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Functional Beads of Polyvinylpyrrolidone: Promising Support Materials for Solid‐Phase Synthesis
Authors: Engström Jonas U. A. , Helgee Bertil
Published: March 2006

Summary: The solubility properties of polyvinylpyrrolidone (PVP) make it an attractive material for several different polymer‐assisted synthesis applications. However, PVP lacks reactive groups necessary for attaching compounds to the polymer. Furthermore, the radical reactivity of 1‐vinylpyrrolidin‐2‐one (NVP) is different from most other monomers, which results in compositional drift during copolymerization. Therefore, introducing reactive groups into the polymer using this method is intricate. Smaller differences in radical reactivity are expected from monomers that are derivatives of NVP itself. Hence, such monomers provide a way of preparing PVP with adjustable properties. Four new monomers containing pendant double bonds, all derivatives of NVP, were synthesized and used in the preparation of a new type of hydrophilic polymer bead by aqueous suspension polymerization. We also found that undec‐10‐en‐1‐ol can be used as a comonomer for the introduction of functional groups. The lightly crosslinked beads contain hydroxyl groups at a functional loading of 0.28 mmol/g and swell extensively in a broad range of solvents. Their potential as support materials has previously been demonstrated in a five‐step solid‐phase synthesis of 5‐(2,4,6‐trimethoxy‐phenyl)‐cyclohexa‐1,3‐dienecarboxylic acid.

Scanning electron microscopy image of dry beads from PVP‐[B]2.

magnified image

Scanning electron microscopy image of dry beads from PVP‐[B]2.
IUPAC International Symposium on Ionic Polymerization Goa, India, IP2005, October 23–28, 2005
Authors: Baskaran Durairaj , Sivaram Swaminathan
Published: March 2006

Conference Reports: This section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de.
Styrenics/Polyamide‐Blends – Reactive Blending and Properties
Authors: Weber Martin , Heckmann Walter , Goeldel Andreas
Published: March 2006

The combination of polyamide 6 (PA 6) and styrene‐butadiene‐acrylonitrile (ABS) to polymer alloys with co‐continuous morphology leads to an interesting combination of properties. Using recent development in the sampling technique for Twin Screw Extruders, the morphology formation in ABS/PA 6 blends and alloys was studied by microscopy and chemical analysis. It could be shown, that the morphology of the alloys is formed in the initial phase of the extrusion step, while in the physical blend a clear correlation between the dispersion of the phases and the residence time could be observed. By chemical analysis further details of the process could be detected.
Influence of the Curing Temperature in the Mechanical and Thermal Properties of Nanosilica Filled Epoxy Resin Coating
Authors: Pascual‐Sánchez Verónica , Martín‐Martínez José Miguel
Published: March 2006

0.5–3 wt% nanosilica was added to an epoxy resin based on diglycidyl ether of bisphenol A (DGEBA) and cured at 25, 40 or 60 °C using isophoronediamine (IPDA) as hardener. Aggregates of nanosilica were properly dispersed into the DGEBA‐IPDA resin and agglomerates formation was avoided. Addition of nanosilica increased the storage modulus E′ and the area and height of the tan δ curve of DGEBA‐IPDA resin cured at 25 °C, but no significant differences were found by curing at higher temperature. Gel time measurements and the results obtained by applying the Kamal model to isotherm DSC curing of DGEBA‐IPDA‐nanosilica revealed that nanosilica catalysed the curing reaction between DGEBA and IPDA, in less extent by increasing the curing temperature.
Mechanical Properties and Morphology of Melt‐mixed PA6/SWNT Composites: Effect of Reactive Coupling
Authors: Bhattacharyya Arup R. , Pötschke Petra
Published: March 2006

An interfacial reaction during melt mixing of maleic anhydride copolymer (SMA) encapsulated single wall carbon nanotubes (SWNT) and polyamide 6 (PA6) was used in order to disperse SWNT homogeneously and to enhance interfacial adhesion. The intended reactive coupling between PA6 and SMA was evident from IR spectroscopy. Nanocomposites with SMA encapsulated SWNT showed increased elongation at break as compared to PA6/SWNT composites. SEM investigation of tensile fractured surfaces of PA6/SWNT+SMA composites indicated enhanced interfacial adhesion between PA6 and SMA modified SWNT.
Brittle‐Ductile Transition in Reactive PBT/SAN Blends
Authors: Lumlong Saisamorn , Kuboyama Keiichi , Chiba Tsuneo , Ougizawa Toshiaki
Published: March 2006

Toughening of reactive poly(butylene terephthalate) (PBT)/styrene‐acrylonitrile copolymer (SAN) blends was studied. PBT/SAN with glycidyl methacrylate (SAN‐GMA) (70/30) behaved in ductile manner on tensile test, while PBT/SAN (70/30) blend failed in brittle manner. Additionally, poly[methylene (phenylene isocyanate)] (PMPI) was added to the PBT/SAN‐GMA blend, where it was expected that PMPI would assist the reaction between PBT and SAN‐GMA, and then the strain at break was improved. PBT/SAN/PMPI (70/30/4) also behaved in ductile manner, although the interfacial adhesion strength between matrix and dispersed phase was extremely weaker than that in PBT/SAN‐GMA blend. From the results, it was found that PMPI acted as a compatibilizer without copolymer formation at the interface and then PBT/SAN behaved in ductile manner in higher SAN content by PMPI effect.
Novel Copolymers as Dispersants/Intercalants/Exfoliants for Polypropylene‐Clay Nanocomposites
Authors: Moad Graeme , Dean Katherine , Edmond Lex , Kukaleva Natalia , Li Guoxin , Mayadunne Roshan T A , Pfaendner Rudolf , Schneider Armin , Simon George , Wermter Hendrik
Published: March 2006

The use of various copolymers as dispersants/intercalants/exfoliants in polypropylene (PP)‐clay nanocomposites based on unmodified montmorillonite clays (NaMMT) has been explored. The primary objective of this research has been to find dispersants that allow PP nanocomposites to be formed by direct melt mixing, that are effective with unmodified clays and that comprise only a minor component of the overall composition both with respect to both clay and PP. Two classes of dispersants were investigated: PEO‐based nonionic surfactants and amphiphilic copolymers based on a long chain (meth)acrylate (e.g. octadecyl acrylate) and a more polar comonomer (e.g. maleic anhydride, N‐vinylpyrrolidone, methyl methacrylate). The state of dispersion achieved and the properties of the derived nanocomposites were found to depend strongly on both on the level of dispersant and its overall composition but interestingly properties are not particularly dependent on the dispersant architecture (i.e. whether statistical, gradient or block copolymer). The nanocomposites possess a tensile modulus up to 40% greater that the precursor PP while elongation at break and impact strength are significantly improved over “clay alone” composites and reference organoclay‐based nanocomposites. Also notable are significantly better thermal and thermo‐oxidative stability as compared to both PP and “clay alone” composites. For optimal properties, it is both necessary and desirable that the surfactant should only be a minor constituent (20–50 wt‐%) of the composition with respect to clay.
Polymer Nanocomposites: How to Reach Low Flammability?
Authors: Bourbigot Serge , Duquesne Sophie , Jama Charaf
Published: March 2006

The paper investigates critically the feasibility to make fire proof polymer using nanoparticles. It includes organoclay, polyhedral oligomeric silsesquioxanes (POSS) and carbon nanotube (CNT). It is shown that they can be used to make material exhibiting low heat release rate (HRR) when they undergo heat. We have developed novel approaches to characterize quantitatively the nanodispersion by solid state NMR and by TEM associated with image analysis and we have demonstrated that the dispersion at the nanoscale is essential to achieve the best performance. On the other hand, low flammability of nanocomposites is only achieved in terms of HRR but they fail in terms of UL‐94 and limiting oxygen index (LOI). To overcome this problem, we have combined nanoparticles with traditional flame retardants (intumescents) or with plasma treatment. The nanofillers act as synergists and offer an exceptional way for making fire safe polymers.
Optimization of Biodegradable Nanocomposites Based on aPLA/PCL Blends for Food Packaging Applications
Authors: Cabedo Lluís , Luis Feijoo José , Pilar Villanueva María , Lagarón José María , Giménez Enrique
Published: March 2006

Biodegradable blends of amorphous poly(lactic acid) (aPLA) and polycaprolactone (PCL) and nanocomposites of these blends were developed by melt blending. A morphological study of the bioblends was carried out by means of WAXS and SEM showing immiscible behavior. The nanocomposites were also characterized morphologically by WAXS, TEM and SEM, revealing high degree of interaction of the nanoclays with the aPLA. Mechanical, thermal and gas barrier properties of the different blends and nanocomposites were studied and the effect of blending and clay addition on the above‐mentioned properties was evaluated.
Influence of the Nanoscale Morphology on the Photovoltaic Properties of Fullerene/MEH‐PPV Composites
Authors: Davenas Joël , Alcouffe Pierre , Ltaief Adnen , Bouazizi Abdelaziz
Published: March 2006

The relation between morphology and photoelectric properties of PPV derivatives/fullerene composites forming bulk heterojunction solar cells has been investigated. The solvent used to spin cast the photoactive layers has a main influence on the quenching of the MEH‐PPV fluorescence, which could be attributed to different dispersion abilities of C60 in the polymer layer shown by AFM microscopy. Formation of large fullerene aggregates is observed at fullerene concentrations of the order of 10% leading to phase separation for composite layers processed in THF, whereas more dispersed distributions of fullerenes are observed in an aromatic solvent like ODCB which accounts for a more efficient luminescence quenching with increasing filler concentrations. However the improvement of the dissociation of photogenerated charge pairs is counterbalanced by a less efficient charge transport in the composite shown by lower short circuit currents probably due to unfavorable polymer chain arrangement in ODCB. Thin film processing conditions have been modified by the preparation of blends of solutions of the polymer in THF and fullerene in ODCB. The resulting spin casted layers show improved morphologies implying better dispersion of the fullerenes and increased short circuit currents. The improvement of the photovoltaic properties of the MEH‐PPV/C60 composites has been attributed to the nanosized fullerene domains formed upon phase separation.
Fire Retarded Insulating Sheets from Recycled Materials
Authors: Matkó Szabolcs , Keszei Sándor , Csontos István , Anna Péter , Marosi György , Zsuga Miklós , Borda Jenő , Nagy Gábor
Published: March 2006

In this work we aimed at forming partially recycled polymer composites of appropriate mechanical properties and flame retardancy. Multilayer composite structures proved to be suitable to fulfill all of these requirements. Core‐shell structures presented here contain two‐component thermosets, i.e. epoxy, recycled polyurethane and polyisocyanurate, as matrices reinforced with waste fillers such as short basalt fibers and wood chips. Flame retardancy and mechanical properties of the core‐shell structures were investigated by the conventional methods of characterization. The developed cost‐effective multilayer composites can be applied as heat and sound insulating panels e.g. multifunctional sheets for construction or automotive industry.
Rheology and Morphology of Highly Compatibilized Polymer Blends
Authors: Van Hemelrijck Ellen , Van Puyvelde Peter , Moldenaers Paula
Published: March 2006

The rheology and morphology of highly compatibilized droplets has been studied, using both rheology and small angle light scattering. It is shown that linear viscoelastic measurements are a powerful tool to investigate the effectiveness of a compatibilizer to suppress coalescence. Moreover, such highly compatibilized droplets are insensitive to deformation and breakup. The consequences for the rheological behaviour of the blend are discussed.
Reaction and Morphology Development Influenced by Diffusion in a Thermoplastic/Thermoset Blend
Authors: Bella Redha , Cassagnau Philippe , Fenouillot Françoise
Published: March 2006

Diglycidyl ether of bisphenol A (DGEBA) and 4,4′‐methylenebis [2,6‐diethylaniline] (MDEA) are miscible in polystyrene at 177 °C. We have studied how their diffusion rate in a molten polystyrene matrix influences their polymerization rate and the morphology of the thermoset particles formed at the end of the reaction. The global composition of the blend was 60 wt% of PS and 40 wt% of epoxy‐amine. The diffusional control of the reaction was evidenced by comparing the time of reaction of an initially homogeneous mixture with that of different bi‐layer samples. The reaction was controled by the diffusion for relatively thick layers (>0.3. mm). A gradient of morphology was obtained due to the diffusionnal control of the reaction. The asymetricity of this gradient may be explained by three factors: differences in diffusion coefficients, in thermodynamic interactions and in viscosity.
Influence of Phase Separation Behaviour on Toughness of Compression Moulded SBS Star Block Copolymer/Polystyrene Blends
Authors: Buschnakowski M. , Adhikari R. , Ilisch S. , Seydewitz V. , Godehardt R. , Lebek W. , Michler G. H. , Knoll K. , Schade C.
Published: March 2006

The influence of homopolymer molecular weight and compression moulding on morphology formation and deformation behaviour of binary blends of polystyrene‐polybutadiene based star block copolymer and polystyrene (PS) homopolymer was investigated. The samples used were a polystyrene‐(polystyrene‐co‐polybutadiene)‐polystyrene (S‐S/B‐S) star block copolymer and anionically prepared polystyrene (aPS). The techniques used were transmission electron microscopy (TEM) and uniaxial tensile testing. A wide range of segregation behaviour was observed depending on the ratio of the length of aPS chains relative to that of corresponding outer blocks of the block copolymer. For the first time, the formation of macrophase‐separated ‘droplet‐like’ morphology has been reported, which endows the block copolymer/polystyrene blends with higher toughness. The mechanical properties of blends are discussed in the light of micromechanical processes of deformation. The micromechanical mechanisms and their dependence with inter domain distance are similar to the mechanisms found in rubber network toughened systems.
Did welfare reform influence the fertility of young teens?
Authors: Lopoo Leonard M. , DeLeire Thomas
Published: March 2006

During the 1990s, states made several reforms to their welfare programs designed to reduce teenage fertility among minors. Among the most prominent of these changes, states started requiring teenage mothers younger than 18 to live with a parent or legal guardian and enroll in high school in order to receive welfare benefits. Using natality data from the National Center for Health Statistics, we compare the trend in fertility rates for young women aged 15 to 17 to the trend for a control group of 18‐year‐olds. Our estimates imply that the annual percent decline in fertility rates following implementation of these minor parent provisions was 0.7 percentage points larger for young teens than for teens aged 18, a difference of over 22 percent. © 2006 by the Association for Public Policy Analysis and Management
Is full better than half? Examining the longitudinal effects of full‐day kindergarten attendance
Authors: Cannon Jill S. , Jacknowitz Alison , Painter Gary
Published: March 2006

Kindergarten policy varies widely both across and within states. Over the past decade, a number of states have instituted a full‐day kindergarten requirement and others are considering it as a way to increase educational achievement. Many parents also support full‐day kindergarten as a source of child care. This paper uses the Early Child Longitudinal Study–Kindergarten Class of 1998–1999 to evaluate the efficacy of this policy. In ordinary least squares, probit, county fixed effects, and instrumental variables models, we find that there are initial benefits for students and the mothers of students who attend full‐day kindergarten, but that these differences largely evaporate by third grade. Contrary to claims by some advocates, attending full‐day kindergarten is found to have no additional benefit for students in families with income below the poverty threshold. © 2006 by the Association for Public Policy Analysis and Management
Attracting private investment to contaminated properties: The value of public interventions
Authors: Wernstedt Kris , Meyer Peter B. , Alberini Anna
Published: March 2006

We employ a mail survey of private developers that uses conjoint choice experiments and Likert‐scaled attitudinal questions to examine preferences for policy instruments and incentives intended to encourage brownfield cleanup and redevelopment. Our analysis suggests that developers judge public hearing requirements at brownfield redevelopments unattractive, but that they place a relatively high value on liability relief—from both cleanup costs and claims by third parties. Reimbursement of environmental assessment costs is not particularly attractive. We also find considerable heterogeneity among developers in the value they place on these incentives, depending on their experience with contaminated sites. © 2006 by the Association for Public Policy Analysis and Management
Public management reform and organizational performance: An empirical assessment of the U.K. Labour government's public service improvement strategy
Authors: Walker Richard M. , Boyne George A.
Published: March 2006

We present the first empirical assessment of the U.K. Labour government's program of public management reform. This reform program is based on rational planning, devolution and delegation, flexibility and incentives, and enhanced choice. Measures of these variables are tested against external and internal indicators of organizational performance. The setting for the study is upper tier English local governments, and data are drawn from a multiple informant survey of 117 authorities. The statistical results indicate that planning, organizational flexibility, and user choice are associated with higher performance. Conclusions are drawn for the theory and practice of public management reform. © 2006 by the Association for Public Policy Analysis and Management
The efficacy and effect of racial profiling: A mathematical simulation approach
Authors: Glaser Jack
Published: March 2006

Racial profiling—the use of race, ethnicity, or national origin by law enforcement officials to make judgments of criminal suspicion—is assessed in terms of its effect on targeted populations and on law enforcement efficiency. A mathematical simulation, comparing multiple profiling and non‐profiling scenarios, is employed. This analysis indicates that racial profiling exacerbates incarceration disparities between groups whether or not the groups differ in criminality rates, and that the long‐term effects of profiling in terms of criminal captures depend on the calibration of profiling rates to criminality rates. The highest long‐term criminal capture rates appear to occur when stop rate ratios match, or are slightly below, criminality rate ratios between groups. When the possibility of a deterrent effect is modeled, profiling appears to yield fewer criminal captures and have little or no crime reduction effect, and may even increase overall crime rates. © 2006 by the Association for Public Policy Analysis and Management
Affirmative action: What do we know?
Authors: Holzer Harry J. , Neumark David
Published: March 2006

An Erratum for this article has been published in Journal of Policy Analysis and Management,26(1), 215.
Treatment of metastatic sialoblastoma with chemotherapy and surgery
Authors: Scott Julius X. , Krishnan Suren , Bourne Anthony J. , Williams Michael P. , Agzarian Marc , Revesz Tamas
Published: March 2006

Tumors of the salivary gland are very uncommon in children. Sialoblastoma is a rare, aggressive, blastomatous, and potentially malignant congenital tumor. Distant metastases are rare. We present a case of sialoblastoma with lung metastases that developed in a 4‐year‐old girl adjacent to a congenital nevus in the left cheek. The tumor was inoperable at diagnosis but the largest of the pulmonary metastases was removed surgically. The patient responded well to chemotherapy and underwent surgical excision of the primary tumor, followed by three more courses of chemotherapy. Pediatr Blood Cancer 2008;50:134–137. © 2006 Wiley‐Liss, Inc.
Multiple brain abscesses in a child with autoimmune hemolytic anemia
Authors: Bay Ali , Yilmaz Nebi , Nalbantoglu Ozlem , Yilmaz Cahide , Etlik Omer , Faik Oner Ahmet
Published: March 2006

A 14‐year‐old female with autoimmune hemolytic anemia (AIHA) developed an acute hemolytic crisis with acute renal failure under conventional treatment with corticosteroids. Because of the life‐threatening situation, we decided to start pulse dose methylprednisolone and also hemodialysis with a femoral catheter placement was performed. Fifteen days after initiating of dialysis subfebrile fever was developed, followed within 2 days with a left hemiparesis. Brain magnetic resonance imaging (MRI) revealed multiple intracerebral abscesses. The clinical picture worsened and the patient died before scheduled surgery for the abscesses. Pediatr Blood Cancer 2007;49:1034–1036. © 2006 Wiley‐Liss, Inc.
Successful management of bleeding with recombinant factor VIIa (NovoSeven®) in a patient with Burkitt lymphoma and thrombosis of the left femoral and left common iliac veins
Authors: Čulić Srđana , Kuljis Dubravka , Armanda Višnja , Jankovic Stipan
Published: March 2006

We present the case of an 18‐year‐old female with Burkitt lymphoma involving the intra‐abdominal and inguinal lymph nodes. The tumor had invaded the left femoral and common iliac veins causing secondary thrombosis and vessel occlusion. Chemotherapy and anticoagulant treatment resulted in mild thrombocytopenia and a prolonged prothrombin time, respectively, which exacerbated postoperative bleeding following surgical removal of a deep inguinal necrosis. After 6 days, bleeding combined with epistaxis was considered to be life threatening and anticoagulant reversal with recombinant factor VIIa was successfully performed. The patient has since achieved complete remission and subsequent antithrombotic therapy has resolved the vascular occlusion. Pediatr Blood Cancer 2007;49:332–335. © 2006 Wiley‐Liss, Inc.
The clinical value of follow‐up examinations in childhood T‐cell acute lymphoblastic leukemia and T‐cell non‐Hodgkin's lymphoma
Authors: Huang L. , Lequin M. , Pieters R. , van den Heuvel‐Eibrink M.M.
Published: March 2006

Background

The aim of this study was to evaluate the value of follow‐up investigations of T‐cell acute lymphoblastic leukemia (T‐ALL) and T‐cell non‐Hodgkin's lymphoma (T‐NHL), including cerebrospinal fluid (CSF) examination, bone marrow (BM) aspiration, peripheral blood (PB) count, serum lactate dehydrogenase (LDH) and chest X‐rays in patients with an initial mediastinal enlargement.

Procedure

We reviewed clinical records of all T‐ALL patients from 1987 to 2002 and all T‐NHL patients from 1977 to 2002, seen at a single institution.

Results

Of 48 T‐ALL patients, 15 suffered from a relapse, 6 (40%) were asymptomatic at the time of relapse. T‐ALL (13/30) with mediastinal enlargement at first diagnosis relapsed versus 2/16 of those without mediastinal enlargement. However, at relapse, only one patient had a mediastinal mass, which in addition was symptomatic. Of 39 T‐NHL patients, 6 patients relapsed. Forty percent of relapsed T‐ALL and 17% of relapsed T‐NHL were asymptomatic. The seven asymptomatic relapses were detected by CSF (n = 4), BM (n = 2) or blood count (n = 1) examinations. All T‐ALL and T‐NHL patients with a mediastinal relapse were symptomatic.

Conclusions

This study suggests that routine CSF examinations during treatment can detect relapses of T‐ALL and T‐NHL before onset of symptoms, which might be of clinical value. Relapses are rarely detected by BM or blood examinations and whether this translates in a clinical benefit is unlikely. Routine chest X‐rays are not useful. Pediatr Blood Cancer © 2006 Wiley‐Liss, Inc.
The anuric preterm newborn infant with a normal renal ultrasound: a diagnostic and ethical challenge
Authors: Waisman Dan , Kessel Irena , Ish‐Shalom Nathan , Maroun Lisa , Riskin‐Mashiah Shlomit , Falik‐Zaccai Tzipora , Weintraub Zalman , Albersheim Susan , Rotschild Avi
Published: March 2006

Diagnosis and treatment of an anuric premature infant with severe respiratory compromise and a normal renal ultrasound (US), is a difficult task that requires a multidisciplinary approach. A 29‐week gestation premature male infant, born after 5 weeks of worsening oligohydramnios, was ventilated for respiratory distress and remained anuric. Intensive clinical investigations and pediatric nephrology consultation that predicted very poor prognosis were followed by progressive renal failure, electrolyte imbalance, respiratory failure, ventricular arrhythmia, and finally cardiac arrest and death on day 5. In view of the predicted poor outcome, and after discussion with the parents, a decision was made not to start peritoneal dialysis (PD), and to offer only palliative therapy, with comfort care alone. Pre and postnatal diagnosis lead, in this case, to an ethical challenge that focuses on the question of futility. Copyright © 2006 John Wiley & Sons, Ltd.
Does prenatal screening influence anxiety levels of pregnant women? A longitudinal randomised controlled trial
Authors: Kleinveld Johanna H. , Timmermans Danielle R. M. , de Smit Denhard J. , J. Adér Herman , van der Wal Gerrit , ten Kate Leo P.
Published: March 2006

Objectives

Questions addressed are: (1) Does offering prenatal screening increase anxiety? (2) Does receiving a negative screening result make women less anxious and does a positive screening result make women more anxious? (3) What are the long‐term consequences on anxiety of offering screening and receiving a screening result?

Methods

Women were offered prenatal screening or no screening in a randomised controlled trial. State anxiety (STAI) and child‐related anxiety (PRAQ‐R) were measured. Questionnaires were filled in before prenatal screening was offered (T1), after the offer (T2), after the test result (T3), and in the third trimester of pregnancy (T4).

Results

Child‐related anxiety levels were higher in women who chose to be screened compared to women who declined screening. Offering prenatal screening did not lead to increased anxiety levels. General anxiety increased in positively screened women, but decreased later in pregnancy. Women who were negatively screened or declined screening scored lower than the control group.

Conclusion

For most women, offering prenatal screening and receiving the test result do not adversely affect anxiety. Giving pregnant women a choice to have prenatal screening done seems to have a small favourable effect on general feelings of anxiety. Copyright © 2006 John Wiley & Sons, Ltd.
Personality, creativity and latent inhibition
Authors: Burch Giles St J. , Hemsley David R. , Pavelis Christos , Corr Philip J.
Published: March 2006

The current study set out to investigate the relationship between creativity, multi‐dimensional schizotypy and personality more generally. This was achieved by analysing scores on a range of personality scales and measures of creativity, where it was found that the creativity measures were more closely related to asocial‐schizotypy than positive‐schizotypy. The study also sought to test Eysenck's prediction (1993, 1995) that, given the putative relationship between creativity and psychosis‐proneness, high psychosis‐prone scoring individuals and high creativity scoring individuals would demonstrate the same cognitive style of ‘overinclusiveness’ on latent inhibition. However, the results failed to demonstrate any evidence of a shared ‘widening of the associative horizon’ between high creativity and high psychosis‐prone scorers. The findings are discussed in relation to multi‐dimensional schizotypy. Copyright © 2006 John Wiley & Sons, Ltd.
Does materialism predict racism? materialism as a distinctive social attitude and a predictor of prejudice
Authors: Roets Arne , Van Hiel Alain , Cornelis Ilse
Published: March 2006

Previous research reported that Right‐Wing Authoritarianism (RWA) and Social Dominance Orientation (SDO) constitute the individual's ideological space and are strong dispositional determinants of racism. In the present study, materialism was examined as a third social attitude and a potential predictor of racism. In a student (N = 183) and heterogeneous adult sample (N = 176) analyses revealed that RWA, SDO and materialism constitute three separate dimensions and that each of them explains a unique part of the variance in racism. In addition, Structural Equation Modelling showed that the relationship between materialism and racism was largely mediated by selfish motives. In the discussion we go further into the role of materialism as a third social attitudinal dimension. Copyright © 2006 John Wiley & Sons, Ltd.
Expected consequences of anger‐related behaviours
Authors: Van Coillie Hermina , Van Mechelen Iven
Published: March 2006

In a study with 140 participants (66 men, 74 women), we investigated behaviour outcome expectancies (cognitive, affective and relational) regarding a broad group of anger‐related behaviours (e.g. hit someone, run away). Results of a three‐mode component analysis indicated that behaviour outcome expectancies vary considerably, depending on the behaviour (aggressive versus nonaggressive ones), the consequence (consequences related to the self versus consequences for the anger) and the individual. The findings are discussed in the context of catharsis theory, emotion regulation and functionalistic accounts of emotion‐related behaviour. Copyright © 2006 John Wiley & Sons, Ltd.
Book Review: Protein‐protein interactions: Methods and applications. By Haian Fu (Ed.)
Authors: Patton Wayne F.
Published: March 2006

No abstracts.
In‐line monitoring of UV photopolymerization with a quartz crystal resonator
Authors: Choi Hee Seok , Kim Young Han , Shin Shun Myung
Published: March 2006

An in‐line monitoring device using a quartz crystal resonator for thin film polymerization was proposed, and its performance has been evaluated by implementing in the UV polymerization of 2‐hydroxyethyl methacrylate with a photoinitiator of 1‐chloroanthraquinone. Because the variation of resonant resistance of the resonator is proportional to the square root of viscosity change that is closely related to the polymerization degree, the resistance can be used as a measure of the polymerization degree. The resistance measurements were compared with the outcome of instrumental analyses of polymerization degree using an FTIR spectrometer and a gel permeation chromatograph. The experimental results showed that the resistance measurements were consistent with the experimental outcome of the instrumental analyses, and this indicates the effectiveness of the proposed device. Owing to the simplicity and availability of the resonator system, its wide utilization in the monitoring of a variety of film polymerization processes, including photoresistor application, is expected. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2428–2439, 2006
Latent reactive polymers containing isocyanate moiety that show extreme stability under aerobic atmosphere
Authors: Kamimura Yasushi , Haba Osamu , Endo Takeshi
Published: March 2006

This article deals with the latent reactive polymers having isocyanate moiety obtained from the radical copolymerization of 2‐propenyl isocyanate (2PI) with styrene, 2PI with methyl methacrylate (MMA), and 2‐methacryloyloxyethyl isocyanate (MOI) with styrene. The radical copolymerization was carried out in benzene (5.00 M by total monomer) in the presence of AIBN (3.00 mol % of total monomer) at 60 °C for 24 h. The isocyanate moiety in each copolymer was stable at room temperature for more than 6 months under aerobic atmosphere, because no change of the infrared absorption based on isocyanate group of the resulting copolymer at around 2250 cm−1 was observed. Isocyanate moiety of obtained copolymer (poly(2PI‐co‐St)) reacted with excess diamines or diols at 80 °C in THF solution to afford the crosslinked polymer quantitatively. These results could demonstrate that isocyanate moiety in the copolymers showed thermal and reactive latency. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2448–2453, 2006