bluuebunny/crossref_metadata_2025 huggingface dataset:
Electric‐Field‐Induced Pattern Morphologies in Thin Liquid Films
Authors: Voicu N. E. , Harkema S. , Steiner U.
Published: March 2006

Liquid‐polymer films sandwiched between two electrodes develop a surface instability caused by the electric field, giving rise to polymer structures that span the two plates. This study investigates the development of the resulting polymer morphologies as a function of time. The initial phase of the structure formation process is a sinusoidal surface undulation, irrespective of the sample parameters. The later stages of pattern formation depend on the relative amount of polymer in the capacitor gap (filling ratio). For high enough filling ratios, the final morphology of the pattern is determined by the partial coalescence of the initial pattern. The introduction of lateral‐field heterogeneities influences the initial pattern formation, with columns nucleated at locations of highest electric field (isolated points or edges). The subsequently formed secondary columns have higher degree of lateral symmetry compared to the pattern formed in a homogeneous field. The nucleation of individual columns or plugs also dominates the pattern formation in the presence of an electrode consisting of an array of lines. The results of this study therefore allow us to draw the conclusion that the accurate replication of structured electrodes typically proceeds by the initial nucleation of individual columns, followed by a coalescence process that yields the polymer replica.
Double‐Inverse‐Opal Photonic Crystals: The Route to Photonic Bandgap Switching
Authors: Ruhl T. , Spahn P. , Hermann C. , Jamois C. , Hess O.
Published: March 2006

Photonic crystals with a complete bandgap can stop the propagation of light of a certain frequency in all directions. We introduce double‐inverse‐opal photonic crystals (DIOPCs) as a new kind of optical switch. In the DIOPC, a movable, weakly scattering sphere is embedded within each pore of the inverse‐opal photonic crystal lattice. Switching between a diffusive reflector and a photonic crystal environment is experimentally demonstrated. Theory shows that a complete bandgap can be realized that can be opened or closed by moving the spheres. This functionality opens up new possibilities for the control of light emission and propagation. The close link and interaction between the chemical synthesis and the computational design and analysis underlines the interdisciplinary focus of this report.
Siloxane surfactants in polymer nanoparticles formulation
Authors: Racles Carmen , Hamaide Thierry , Ioanid Aurelia
Published: March 2006

Carbohydrate‐modified cyclosiloxanes were synthesized by hydrosilylation reactions of protected allyl‐monosaccharides and subsequent deprotection with a gel‐type ion exchanger. They were characterized by 1H and 13C‐NMR, FT‐IR, GPC and surface tension measurements. These compounds, as well as other water soluble, carboxylate‐based siloxanes were tested as stabilizers in nanoparticle formulations, with polydimethylsiloxane (PDMS), poly(ε‐caprolactone) (PCL) and UDEL polysulfone (PSF) as polymer cores. Owing to their low critical micelle concentrations (cmc), small amounts of surfactants were required. The particle size and granulometric distribution were measured by dynamic light scattering (DLS). Electron microscopy confirmed the DLS results and revealed aggregation phenomena in dry state, depending on the polymer core. In the tested conditions, the glass transition temperature of the polymer seems to be the driving force for the stability of dry nanoparticles. Copyright © 2006 John Wiley & Sons, Ltd.
A brief survey on the copper‐catalyzed allylation of alkylzinc and Grignard reagents under Barbier conditions
Authors: Erdik Ender , Koçoğlu Melike
Published: March 2006

The same regioselectivity can be obtained in the CuI catalyzed allylic coupling ofn‐butylzinc reagents prepared by either pre‐transmetallation orin situtransmetallation of Grignard reagents in the presence of allylic partner and catalyst.n‐Butylzinc bromide and di‐n‐butylzinc undergo γ‐selective allylation whereas tri‐n‐butylzincate gives preferential α‐selectivity. The regioselectivity obtained in the reaction ofn‐butyl bromide andE‐crotyl chloride in the presence of Mg and CuCN is parallel to the coupling of preformedn‐butylmagnesium bromide. It is remarkable that the regiochemical outcome of copper catalyzed alkyl‐allyl coupling can be controlled by using Grignard reagents prepared under Barbier conditions and alkylzincs prepared byin situtransmetallation. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis of solid epoxy resins base on BPC II and bisphenol A using conventional heating equipment and microwave
Authors: Brzozowski Zbigniew K. , Staszczak Sylwia K. , Hadam Lukasz K. , Rupinski Slawomir , Bogdal Dariusz , Gorczyk Jaroslaw
Published: March 2006

New solid state epoxy resins based on diglycidyl ether of 1,1‐dichloro‐2,2 bis (4‐hydroxyphenyl), ethylene (BPC) and BPA epoxy resins in the reaction with BPC and BPA were developed. Solid epoxy resins were synthesised by the use of two different heating methods: conventional and microwave reactor. The use of microwave radiation as novel heating medium as an alternative to the conventional methods, which provide a quicker and more effective synthesis. The solid epoxies have high melting points higher than 100°C and the polycondensation degree remains between n = 4–12. Epoxy value stays low and occurs around 0,02–0,1. BPA epoxy resins and diglycidylether of BPC II were compared in terms of reaction speed. It can be seen that the reaction of BPC diglycidylether occurs approximately 20% quicker given the same reaction conditions of temperature, and balance of catalyst. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3850–3854, 2006
Effects of activation temperature on the properties and structure of PAN‐based activated carbon hollow fiber
Authors: Sun Junfen , Wang Qingrui
Published: March 2006

Polyacrylonitrile (PAN) hollow fibers were pretreated with ammonium dibasic phosphate, then further oxidized in air, carbonized in nitrogen, and activated with carbon dioxide. The effects of activation temperature of a precursor fiber on the microstructure, specific surface, pore‐size distribution, and adsorption properties of PAN‐based activated carbon hollow fibers (PAN‐ACHF) were studied in this work. After the activation process, the BET surface area of the PAN‐ACHF and surface area of mesopores in the PAN‐ACHF increased very remarkably and reached 1422 m2 g−1 and 1234 m2 g−1, respectively, when activation temperature is 1000°C. The adsorptions to creatinine and VB12 of PAN‐ACHF were much high and reached 99 and 84% respectively. In PAN‐ACHF which went through the activation at 700°C and 800°C, the micropore filling mainly occurred at low relative pressures, multimolecular layer adsorption occurred with the increasing of relative pressure, and the filling and emptying of the mesopores by capillary condensation occurred at high relative pressures. But in PAN‐ACHF which went through the activation at 900°C, a mass of mesopores resulted in the large pore filling by capillary condensation. The dominant pore sizes of mesopores in PAN‐ACHF are from 2 nm to 5 nm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3778–3783, 2006
Study of poly(vinyl chloride) interfaces using slow positron beams
Authors: Mostafa N.
Published: March 2006

Elemental and X‐ray fluorescence analyses were performed to determine the chemical compositions of insulator and jacket poly(vinyl chloride) (PVC) samples. In addition, differential scanning calorimetry (DSC) measurement was performed to determine their glass‐transition temperatures (Tg) and melting points. The effect of additives on the two investigated samples, as well as on a pure PVC sample, was studied using Doppler‐broadening energy spectra coupled with the slow positron beam technique. Significant variation in the S parameter as a function of positron implantation energy and depth from the surface to the bulk was observed in all samples. The S parameter increased at a very low positron energy (< 1 keV), saturated to about 6 keV, and then decreased up to 27 keV. The S parameter (ΔS) changed to the extent of the change in the breadth of the distribution of free‐volume defects, which was larger in the jacket PVC sample, which had more additives, than in the insulator PVC sample. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3789–3793, 2006
Crystallization behavior of carbon nanotubes‐filled polyamide 1010
Authors: Wang Biao , Sun Guangping , Liu Jingjiang , He Xiaofeng , Li Jing
Published: March 2006

The nanocomposites of polyamide1010 (PA1010) filled with carbon nanotubes (CNTs) were prepared by melt mixing techniques. The isothermal melt‐crystallization kinetics and nonisothermal crystallization behavior of CNTs/PA1010 nanocomposites were investigated by differential scanning calorimetry. The peak temperature, melting point, half‐time of crystallization, enthalpy of crystallization, etc. were measured. Two stages of crystallization are observed, including primary crystallization and secondary crystallization. The isothermal crystallization was also described according to Avrami's approach. It has been shown that the addition of CNTs causes a remarkable increase in the overall crystallization rate of PA1010 and affects the mechanism of nucleation and growth of PA1010 crystals. The analysis of kinetic data according to nucleation theories shows that the increment in crystallization rate of CNTs/PA1010 composites results from the decrease in lateral surface free energy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3794–3800, 2006
Reactivity ratios of acrylamide–vinyl pyrrolidone copolymerization system obtained by sequential sampling
Authors: Akyüz Ali , Paril Ahmet , Giz Ahmet
Published: March 2006

Free‐radical copolymerization of vinyl pyrrolidone and acrylamide was performed in water at 60°C. Their copolymerization reactions were continued up to high conversions and reaction mixture sampled sequentially during the reaction. The compositions of the aliquots were measured by UV spectroscopy, and their polymer contents were obtained by gravimetry. Data are evaluated by a recent error in variables method developed for sequential sampling. Reactivity ratios are found as rA = 2.03 ± 0.14, rVP = 0.09 ± 0.02. Analysis of the data up to 45% conversion by the Extended Kelen Tüdös method gave consistent results. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3822–3827, 2006
Fractal model of the heat conductivity for carbon fiber‐reinforced aromatic polyamide
Authors: Kozlov G. V. , Burya A. I. , Dolbin I. V. , Zaikov G. E.
Published: March 2006

It is shown that the heat conductivity of carbon fiber (CF)‐reinforced aromatic polyamide on the basis of phenylone can be described within the framework of a fractal model. Depending on the dimension of filler fibers network (system), such description can be obtained by the application of two limiting cases: random network of resistors (RNR) or random superconducting network (RSN). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3828–3831, 2006
Nanostructure development in wet amorphous amylopectin as revealed by in situ X‐ray scattering methods
Authors: Bayer R. K. , Baltá‐Calleja F. J.
Published: March 2006

Completely amorphous, transparent bars of amylopectin were prepared by injection molding of pure native semicrystalline samples (Waxy Maize). The formation of a semicrystalline morphology was studied during annealing treatment at various temperatures in a wet atmosphere, using simultaneous WAXS and SAXS. Amylopectin samples crystallized during 20 days in a humid atmosphere at room temperature and subjected to a successive melting process were also studied by X‐ray scattering. Results indicate that individual molecules crystallize independently from each other, similar to the case of native amylopectin grains. During the first stages of crystallization, the changes in the SAXS pattern suggest that uncorrelated crystal blocks are formed, which may arrange to lamellae (if a secondary network of double‐helix net‐points is hydrothermally dissociated). At the beginning of the crystallization process, only few amylopectin molecules (about 10%) are incorporated into the nanostructure. A shell‐like structure of semicrystalline layers, comparable to that of a native grain, develops. When crystallization proceeds further, the initially thin shell layers thicken. This causes the amorphous interlayers to be subjected to inner tensions, leading to a decrease in the melt temperature. After a storage time of 20 days in a humid atmosphere, amylopectin reaches a crystallinity level of 54%, only slightly lower than that of the initial native grains. Upon heating the retrograded amylopectin, immediately before complete melting, the long‐period shows a value of 15 nm with a crystal thickness, derived from WAXS, of only 4 nm. Such a structure, which has not been reported before, is due to the relaxations of the inner tensions during melting, which lead to a disappearance of inserted interlamellar crystals. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3832‐3839, 2006
Miscibility and transesterification in ternary blends of poly(ethylene naphthalate)/poly(pentamethylene terephthalate)/poly(ether imide)
Authors: Su Chean Cheng , Shih Chih Kuan
Published: March 2006

Miscibility and morphology of poly(ethylene 2,6‐naphthalate)/poly(pentamethylene terephthalate)/poly(ether imide) (PEN/PPT/PEI) blends were studied by differential scanning calorimetry (DSC), optical microscopy (OM), proton nuclear magnetic resonance imaging (1H‐NMR), and wide‐angle X‐ray diffraction (WAXD). OM and DSC results from ternary blends revealed the immiscibility of PEN/PPT/PEI blends, but ternary blends of all compositions were phase‐homogeneous following heat treatment at 300°C for over 60 min. Annealing samples at 300°C yielded an amorphous blend with a clear and single Tg at the final state. Experimental data from 1H‐NMR revealed that PEN/PPT copolymers (ENPT) were formed by the so‐called transesterification. The effect of transesterification on glass transition and crystallization was discussed in detail. The sequence structures of the copolyester were identified by triad analysis, which showed that the mean sequence lengths became shorter and the randomness increased with heating time. The results reveal that a random copolymer improved the miscibility of the ternary blends, in which, the length of the homo segments in the polymer chain decreased and the crystal formation was disturbed because of the irregularity of the structure, as the exchange reaction proceeded. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3840–3849, 2006
Apparent active transport of MDMA is not mediated by P‐glycoprotein: a comparison with MDCK and Caco‐2 monolayers
Authors: Bertelsen Kirk M. , Greenblatt David J. , von Moltke Lisa L.
Published: March 2006

Amphetamines and their methylenedioxy derivatives generically display similar behavioral, physiologic and toxic effects. Inconsistent pharmacokinetic and toxicity data for methylenedioxymethamphetamine (MDMA) may suggest that active drug transporters are interacting with these compounds, and thus altering drug absorption and tissue distribution.In vitromodels of CNS accumulation and intestinal drug transport were used to assess efflux transport of MDMA. Madin‐Darby kidney cell epithelial (MDCK) monolayers displayed a 4‐fold increase in accumulation in the basolateral to apical orientation relative to the apical to basolateral orientation, although no differential accumulation was noted between MDCK‐WT and MDCK‐MDR1 monolayers. Caco‐2 monolayers demonstrated an approximate 2‐fold increase in accumulation of MDMA. Exposure of various inhibitors of active drug transporters demonstrated mixed results; ritonavir, progesterone and indomethacin produced an approximately 50% reduction of MDMA transport, while verapamil, MK‐571 and probenecid had no effect. Based on these data, it is concluded that MDMA efflux is mediated via the activity of a transporter distinct from P‐glycoprotein. The possible inhibitory effects of amphetamines on rhodamine‐123 transport were also assessed. MDMA, methylenedioxyamphetamine, amphetamine and methamphetamine, at physiologically relevant concentrations, did not significantly alter the transport of rhodamine‐123 in Caco‐2 monolayers or the LS180 cell line, suggesting that these compounds do not alter the function of P‐glycoprotein. Copyright © 2006 John Wiley & Sons, Ltd.
A minimalistic 3D pharmacophore model for cyclopentapeptide CXCR4 antagonists
Authors: Våbenø Jon , Nikiforovich Gregory V. , Marshall Garland R.
Published: March 2006

Because of its involvement in HIV entry, the chemokine receptor CXCR4 is an attractive target for antiretroviral drugs. Despite the large number of CXCR4 inhibitors studied, the 3D pharmacophore for binding to CXCR4 remains elusive, mainly as a result of conformational flexibility inherent in the identified ligands. In the present study, an exhaustive systematic exploration of the conformational space for a series of analogs of FC131, a cyclopentapeptide CXCR4 antagonist, has been performed. By comparing the resulting low‐energy conformations using different sets of atoms, specific conformational features common only to the high/medium affinity compounds were identified. These features included the spatial arrangement of three pharmacophoric side chains as well as the orientation of a specific backbone amide bond. Together these features represent a minimalistic 3D pharmacophore model for binding of the cyclopentapeptide antagonists to CXCR4. The model enables rationalization of the experimental affinity data for this class of compounds as well as for the peptidomimetic KRH‐1636. © 2006 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 84: 459–471, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
One‐pot synthesis in aqueous system for water‐soluble chitosan‐graft‐poly(ethylene glycol) methyl ether
Authors: Fangkangwanwong J. , Akashi Mitsuru , Kida Toshiyuki , Chirachanchai Suwabun
Published: March 2006

Chitosan is functionalized with poly(ethylene glycol) methyl ether (mPEG) at the amino and hydroxyl groups via a single step reaction in a homogeneous aqueous system. A chitosan aqueous solution obtained from the mixture of chitosan and hydroxybenzotriazole (HOBt) in water is a key factor in providing mild conditions to conjugate mPEG by using a carbodiimide conjugating agent. The reaction at ambient temperature for 24 h gives chitosan‐g‐mPEG with water solubility with mPEG content as high as 42%. This work demonstrates that a water‐soluble chitosan–HOBt complex is an effective system for the preparation of chitosan derivatives via the aqueous system without the use of acids or organic solvents. © 2006 Wiley Periodicals, Inc. Biopolymers 82:580–586, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Solid‐state IR–LD spectroscopic and theoretical analysis of glycine‐containing peptides and their hydrochlorides
Authors: Ivanova Bojidarka B. , Kolev Tsonko , Zareva Sonya Y.
Published: March 2006

As part of an investigation on the coordination ability of peptides, structural analyses of the solid di‐, tri, and tetrapeptides glycyl‐glycine (GG), glycyl‐glycyl‐glycine (GGG), glycyl‐glycyl‐glycyl‐glycine (GGGG), and their protonated hydrochlorides glycyl‐glycine·HCl (GGH), glycyl‐glycyl‐glycine·HCl (GGGH), and glycyl‐glycyl‐glycyl‐glycine·HCl (GGGGH) have been carried out. The quantum chemical calculations (Hartree‐Fock/6‐31++G**) and linear–dichroic infrared (IR–LD) spectroscopy predict a near to linear structure of the pure ligands, but the experimental IR–LD data are in accordance with a cross‐linked disposition of amide fragments in the protonated forms. © 2006 Wiley Periodicals, Inc. Biopolymers 82:587–596, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Facile preparation of biodegradable chitosan derivative having poly(butylene glycol adipate) side chains
Authors: Huang Meifang , Fang Yue'e
Published: March 2006

Various modes are being explored for the construction of functional materials from nanoparticles. Despite these efforts, the assembly of nanoparticles remains challenging with respect to the requirement of multiple component organization on varying dimensions and length scales. The graft copolymers of chitosan with poly(butylene glycol adipate) (PBGA) were prepared due to the esterification reaction between PBGA and 6‐O‐succinate‐N‐phthaloyl‐chitosan (PHCSSA) in the presence of toluene as a swelling agent. The graft copolymers are nanoparticles with the size of few hundred nanometers as observed from TEM. It is a potential method to combine chitosan with the hydrophobic synthetic polymers. The grafting reactions were conducted with various PBGA/PHCSSA feed ratios to obtain chitosan‐g‐PBGA copolymers with various PBGA contents. FT–IR, NMR, XRD, spectrofluorophotometer, and TEM were detected to characterize the copolymers. © 2006 Wiley Periodicals, Inc. Biopolymers 82:597–602, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Reduction in wound infection rates by wound surveillance with postdischarge follow-up and feedback
Authors: Wilson A P R , Hodgson B , Liu M , Plummer D , Taylor I , Roberts J , Jit M , Sherlaw-Johnson C
Published: March 2006

Background

Surgical wound surveillance with postdischarge follow-up is rarely done in the UK as it is seen as expensive. The aim of this study was to determine whether employing a dedicated team was effective and reduced costs.

Methods

Infection data were collected prospectively with postdischarge follow-up at 2–3 months, and fed back to surgeons. Wound infection was defined using both ASEPSIS wound scoring and criteria of the US Centers for Disease Control (CDC) definitions.

Results

Over 4 years, 15 548 patient episodes were included. Postdischarge surveillance data were available for 79·9 per cent of the 15 154 records of patients who survived. There was a significant reduction in the rate of wound infection between the first and fourth years by ASEPSIS and CDC definitions: odds ratio 0·77 (95 per cent confidence interval (c.i.) 0·64 to 0·92) and 0·69 (95 per cent c.i. 0·57 to 0·83), respectively. The proportion of infections fell significantly in orthopaedic, cardiac and thoracic surgery. The annual budget for wound surveillance was £91 600. Changes in infection rates contributed £347 491 to the reduction in cost among the patients surveyed.

Conclusion

Wound surveillance was associated with a reduction in rates of wound infection within 4 years. The cost reduction as a result of fewer infections exceeded the cost of surveillance after 2 years.
Leucocyte depletion improves renal function during reperfusion using an experimental isolated haemoperfused organ preservation system
Authors: Harper S , Hosgood S , Kay M , Nicholson M
Published: March 2006

Background

Leucocytes have been implicated as mediators of renal ischaemia–reperfusion injury. This study aimed to demonstrate the effect of white cells in early renal reperfusion injury using an isolated haemoperfused porcine kidney model.

Methods

After 2 h cold storage, porcine kidneys were perfused with normothermic autologous blood using an isolated organ preservation system. This was designed using cardiopulmonary bypass technology, and perfusion commenced with a circulating serum creatinine level of 1000 µmol/l. In group 1 (n = 6) a leucocyte filter was included in the circuit and in group 2 (n = 6) non-filtered blood was used.

Results

The mean(s.d.) area under the curve for serum creatinine was lower in the leucocyte-depleted experiments (1286(214) versus 2627(418); P = 0·002). Leucocyte depletion also led to improved urine output (191(75) versus 70(32) ml/h; P = 0·002) and higher creatinine clearance (10·6(2·8) versus 1·9(1·0) ml/min; P = 0·002). Renal blood flow, oxygen consumption and acid–base homeostasis were all improved by perfusion with leucocyte-depleted blood, and histological tubular damage was ameliorated.

Conclusion

These data show that the depletion of leucocytes from blood used to perfuse porcine kidneys improved postschaemic renal function, indicating that white cells play an important role in renal ischaemia–reperfusion injury.
Synthesis, Characterization, and Theoretical Study of Stable Isomers of C70(CF3)n (n = 2, 4, 6, 8, 10)
Authors: Dorozhkin Eugenii I. , Ignat'eva Daria V. , Tamm Nadezhda B. , Goryunkov Alexey A. , Khavrel Pavel A. , Ioffe Ilya N. , Popov Alexey A. , Kuvychko Igor V. , Streletskiy Alexey V. , Markov Vitaliy Y. , Spandl Johann , Strauss Steven H. , Boltalina Olga V.
Published: March 2006

Reaction of C70 with ten equivalents of silver(I) trifluoroacetate at 320–340 °C followed by fractional sublimation at 420–540 °C and HPLC processing led to the isolation of a single abundant isomer of C70(CF3)n for n = 2, 4, 6, and 10, and two abundant isomers of C70(CF3)8. These six compounds were characterized by using matrix‐assisted laser desorption ionization (MALDI) mass spectrometry, 2D‐COSY and/or 1D 19F NMR spectroscopy, and quantum‐chemical calculations at the density functional theory (DFT) level. Some were also characterized by Raman spectroscopy. The addition patterns for the isolated compounds were unambiguously found to be C1‐7,24‐C70(CF3)2, C1‐7,24,44,47‐C70(CF3)4, C2‐1,4,11,19,31,41‐C70(CF3)6, Cs‐1,4,11,19,31,41,51,64‐C70(CF3)8, C2‐1,4,11,19,31,41,51,60‐C70(CF3)8, and C1‐1,4,10,19,25,41,49,60,66,69‐C70(CF3)10 (IUPAC numbering). Except for the last compound, which is identical to the recently reported, crystallographically characterized C70(CF3)10 derivative prepared by a different synthetic route, these compounds have not previously been shown to have the indicated addition patterns. The largest relative yield under an optimized set of reaction conditions was for the Cs isomer of C70(CF3)8 (ca. 30 mol % of the sublimed mixture of products based on HPLC integration). The results demonstrate that thermally stable C70(CF3)n isomers tend to have their CF3 groups arranged on isolated para‐C6(CF3)2 hexagons and/or on a ribbon of edge‐sharing meta‐ and/or para‐C6(CF3)2 hexagons. For Cs‐ and C2‐C70(CF3)8 and for C2‐C70(CF3)6, the ribbons straddle the C70 equatorial belt; for C1‐C70(CF3)4, the para–meta–para ribbon includes three polar hexagons; for C1‐7,24‐C70(CF3)2, the para‐C6(CF3)2 hexagon includes one of the carbon atoms on a C70 polar pentagon. The 10.3–16.2 Hz 7JF,F NMR coupling constants for the end‐of‐ribbon CF3 groups, which are always para to their nearest‐neighbor CF3 group, are consistent with through‐space Fermi‐contact interactions between the fluorine atoms of proximate, rapidly rotating CF3 groups.
Evidence that the canonical Wnt signalling pathway regulates deer antler regeneration
Authors: Mount J. G. , Muzylak M. , Allen S. , Althnaian T. , McGonnell I. M. , Price J. S.
Published: March 2006

Wnt signalling regulates many developmental processes, including the fate specification, polarity, migration, and proliferation of cranial neural crest. The canonical Wnt pathway has also been shown to play an important role in bone physiology and there is evidence for its recapitulation during organ regeneration in lower vertebrates. This study explores the role of the Wnt signalling pathway in deer antlers, frontal bone appendages that are the only mammalian organs capable of regeneration. Immunocytochemistry was used to map the distribution of the activated form of β‐catenin (aβCAT). A low level of aβCAT staining was detected in chondrocytes and in osteoblasts at sites of endochondral bone formation. However, aβCAT was localised in cellular periosteum and in osteoblasts in intramembranous bone, where it co‐localised with osteocalcin. The most intense aβCAT staining was in dividing undifferentiated cells in the mesenchymal growth zone. Antler progenitor cells (APCs) were cultured from this region and when the canonical Wnt pathway was inhibited at the level of Lef/TCF by epigallocatechin gallate (EGCG), the cell number decreased. TUNEL staining revealed that this was as a result of increased apoptosis. Activation of the pathway by lithium chloride (LiCl) had no effect on cell number but inhibited alkaline phosphate activity (ALP), a marker of APC differentiation, whereas EGCG increased ALP activity. This study demonstrates that β‐catenin plays an important role in the regulation of antler progenitor cell survival and cell fate. It also provides evidence that β‐catenin's function in regulating bone formation by osteoblasts may be site‐specific. Developmental Dynamics 235:1390–1399, 2006. © 2006 Wiley‐Liss, Inc.
Opposite roles of neutrophils and macrophages in the pathogenesis of acetaminophen‐induced acute liver injury
Authors: Ishida Yuko , Kondo Toshikazu , Kimura Akihiko , Tsuneyama Kouichi , Takayasu Tatsunori , Mukaida Naofumi
Published: March 2006

Neutrophils and macrophages infiltrate after acetaminophen (APAP)‐induced liver injury starts to develop. However, their precise roles still remain elusive. In untreated and control IgG‐treated wild‐type (WT) mice, intraperitoneal APAP administration (750 mg/kg) caused liver injury including centrilobular hepatic necrosis and infiltration of neutrophils and macrophages, with about 50% mortality within 48 h after the injection. APAP injection markedly augmented intrahepatic gene expression of inducible nitric oxide synthase (iNOS) and heme oxygenase (HO)‐1. Moreover, neutrophils expressed iNOS, which is presumed to be an aggravating molecule for APAP‐induced liver injury, while HO‐1 was mainly expressed by macrophages. All anti‐granulocyte antibody‐treated neutropenic WT and most CXC chemokine receptor 2 (CXCR2)‐deficient mice survived the same dose of APAP, with reduced neutrophil infiltration and iNOS expression, indicating the pathogenic roles of neutrophils in APAP‐induced liver injury. However, APAP caused more exaggerated liver injury in CXCR2‐deficient mice with reduced macrophage infiltration and HO‐1 gene expression, compared with neutropenic WT mice. An HO‐1 inhibitor, tin‐protoporphyrin‐IX, significantly increased APAP‐induced mortality, implicating HO‐1 as a protective molecule for APAP‐induced liver injury. Thus, CXCR2 may regulate the infiltration of both iNOS‐expressing neutrophils and HO‐1‐expressing macrophages, and the balance between these two molecules may determine the outcome of APAP‐induced liver injury.
A role for the Hsp90 molecular chaperone family in antigen presentation to T lymphocytes via major histocompatibility complex class II molecules
Authors: Rajagopal Deepa , Bal Vineeta , Mayor Satyajit , George Anna , Rath Satyajit
Published: March 2006

The heat shock protein (HSP) Hsp90 is known to chaperone cytosolic peptides for MHC class I (MHCI)‐restricted antigen presentation to T lymphocytes. We now demonstrate a role for Hsp90 activity in presentation of antigens on MHCII. Treatment of mouse antigen‐presenting cells (APC) with the pharmacological Hsp90 inhibitor, geldanamycin, inhibited MHCII‐mediated presentation of endocytosed and cytosolic proteins as well as synthetic peptides to specific T cells. Ectopic expression of human Hsp90 in APC enhanced MHCII‐mediated antigen presentation. Further, pharmacological Hsp90 inhibition reduced, while retroviral Hsp90 overexpression enhanced, the levels of stable compact MHCII heterodimers correlating with the antigen presentation phenotype. Pharmacological inhibition of Hsp90 activity in IFN‐γ‐treated APC resulted in severe abrogation of MHCII‐restricted presentation of cytosolic antigen, but only partially inhibited exogenous antigen presentation. Our data suggest a major role for Hsp90 activity in MHCII‐mediated antigen presentation pathways, and implicate IFN‐γ‐inducible Hsp90‐independent mechanisms.
Immunoadsorption against two distinct epitopes on human type XVII collagen abolishes dermal‐epidermal separation induced in vitro by autoantibodies from pemphigoid gestationis patients
Authors: Herrero‐González Josep E. , Brauns Olaf , Egner Ralf , Rönspeck Wolfgang , Mascaró José M. , Jonkman Marcel F. , Zillikens Detlef , Sitaru Cassian
Published: March 2006

Pemphigoid gestationis (PG) is a subepidermal autoimmune blistering disease characterized by self‐reactive T and B cells specific for the transmembrane hemidesmosomal protein type XVII collagen/BP180. Major T and B cell epitopes are located within the immunodominant 16th non‐collagenous domain A (NC16A) of type XVII collagen. The aim of the present study was to map the pathogenically relevant epitopes targeted by blister‐inducing patients’ autoantibodies. For this purpose, we used an in vitro model of autoantibody‐induced leukocyte‐dependent dermal‐epidermal separation. Pre‐adsorption against a recombinant form of the NC16A region abolished the blister‐inducing potential of autoantibodies from all PG patients. Using overlapping synthetic peptides, we demonstrated that PG autoantibodies bind to two defined epitopes within the NC16A region (aa 500–514 and aa 511–523). Importantly, pre‐adsorption using an affinity matrix containing these epitopes completely abolished dermal‐epidermal separation induced by PG autoantibodies. This study identifies the epitopes relevant for blister induction in PG and should facilitate the development of an antigen‐specific immunoadsorption therapy for this disease.
Cytoskeleton rearrangement induced by tetraspanin engagement modulates the activation of T and NK cells
Authors: Crotta Stefania , Ronconi Vanessa , Ulivieri Cristina , Baldari Cosima T. , Valiente Nicholas M. , Abrignani Sergio , Wack Andreas
Published: March 2006

The hepatitis C virus (HCV) binds to human cells through the interaction of its envelope glycoprotein E2 with the tetraspanin CD81. We have previously reported that engagement of CD81 has opposite effects on T and NK cell function, as it enhances T cell receptor‐mediated T cell activation and inhibits CD16‐ or IL‐12‐mediated NK cell activation. We further investigated this dichotomy and found that another tetraspanin, CD82, induces the same opposing effects on human primary T and NK cells. Activation by other unrelated stimuli such as NKG2D‐ and beta‐1 integrin is also reduced by CD81 ligation on NK cells. CD81 engagement by monoclonal antibody or HCV‐E2 enhances zeta and Erk phosphorylation in T cells and reduces them in NK cells, reflecting the opposite functional outcomes. CD81 engagement induces dramatic morphological changes and local F‐actin accumulation in both NK and T cells, indicating rearrangement of the actin cytoskeleton. Pharmacological inhibition of actin polymerization reduces T cell activation, whereas it greatly enhances NK cell activation. Importantly, treatment with actin blockers abolishes the inhibitory effect of CD81 ligation on NK cells. We propose that tetraspanin engagement leads to comparable cytoskeleton reorganization in T and NK cells, which in turn results in opposite functional outcomes.
Expression of the class A macrophage scavenger receptor on specific subpopulations of murine dendritic cells limits their endotoxin response
Authors: Becker Mike , Cotena Alessia , Gordon Siamon , Platt Nick
Published: March 2006

Dendritic cells (DC) function at the interface of innate and acquired immunity and are uniquely sensitive to specific stimuli. Pattern recognition receptors (PRR) on these cells are critically important because of their ability to recognise and initiate responses to conserved microbial‐associated molecular signatures. With the exception of Toll‐like receptors (TLR), we know relatively little about the specific distribution of other PRR amongst populations of DC. Here, we describe the expression of the murine class A macrophage scavenger receptor (SR‐A) and show that it is restricted to specific subpopulations of bone marrow‐derived and splenic DC. Importantly, we demonstrate that the receptor significantly alters the response of DC to endotoxin. In contrast to the activities of other PRR that have so far been examined, uniquely SR‐A limits the maturation response; SR‐A–/– cells display enhanced CD40 expression and TNF‐α production. We discuss the potential contributions of SR‐A to DC biology in the context of the known multiple activities of this receptor.
Automatic CAD model topology generation
Authors: Patel Paresh S. , Marcum David L. , Remotigue Michael G.
Published: March 2006

Computer aided design (CAD) models often need to be processed due to the data translation issues and requirements of the downstream applications like computational field simulation, rapid prototyping, computer graphics, computational manufacturing, and real‐time rendering before they can be used. Automatic CAD model processing tools can significantly reduce the amount of time and cost associated with the manual processing. The topology generation algorithm, commonly known as CAD repairing/healing, is presented to detect commonly found geometrical and topological issues like cracks, gaps, overlaps, intersections, T‐connections, and no/invalid topology in the model, process them and build correct topological information. The present algorithm is based on the iterative vertex pair contraction and expansion operations calledstitchingandfilling, respectively, to process the model accurately. Moreover, the topology generation algorithm can process manifold as well as non‐manifold models, which makes the procedure more general and flexible. In addition, a spatial data structure is used for searching and neighbour finding to process large models efficiently. In this way, the combination of generality, accuracy, and efficiency of this algorithm seems to be a significant improvement over existing techniques. Results are presented showing the effectiveness of the algorithm to process two‐ and three‐dimensional configurations. Copyright © 2006 John Wiley & Sons, Ltd.
Numerical analysis of mixed convection in three‐dimensional rectangular channel with flush‐mounted heat sources based on field synergy principle
Authors: Cheng Y. P. , Lee T. S. , Low H. T.
Published: March 2006

In this paper the fluid flow and heat transfer characteristics of mixed convection in three‐dimensional rectangular channel with four heat sources are investigated numerically. The SIMPLEC algorithm is applied to deal with the coupling between pressure and velocity, and a new high‐order stability‐guaranteed second‐order difference (SGSD) scheme is adopted to discretize the convection term. The influence of four parameters is studied: Richardson number, heat source distribution, channel height and inclination angle. The numerical results are analysed from the viewpoint of the field synergy principle, which says that the enhanced convective heat transfer is related not only to the velocity field and temperature field, but also to the synergy between them. It is found that the effects of the four parameters on the thermal performance can all be explained with the field synergy principle. To obtain better electronic cooling, the synergy between the velocity and temperature gradient should be increased when other conditions are unchanged. Copyright © 2006 John Wiley & Sons, Ltd.
A fractional two‐step implicit algorithm using curvilinear collected grids
Authors: Ye Jian , McCorquodale J. A. , Peng Jian
Published: March 2006

An efficient fractional two‐step implicit algorithm is reported to simulate incompressible fluid flows in a boundary‐fitted curvilinear collocated grid system. Using the finite volume method, the convection terms are discretized by the high‐accuracy Roe's scheme to minimize numerical diffusion. An implicitness coefficient Π is introduced to accelerate the rate of convergence. It is demonstrated that the proposed algorithm links the fractional step method to the pressure correction procedure, and the SIMPLEC method could be considered as a special case of the fractional two‐step implicit algorithm (when Π=1). The proposed algorithm is applicable to unsteady flows and steady flows. Three benchmark two‐dimensional laminar flows are tested to evaluate the performance of the proposed algorithm. Performance is measured by sensitivity analyses of the efficiency, accuracy, grid density, grid skewness and Reynolds number on the solutions. Results show that the model is efficient and robust. Copyright © 2006 John Wiley & Sons, Ltd.
Effects of different phases of an invitational screening program on breast cancer incidence
Authors: Seppänen Johanna , Heinävaara Sirpa , Anttila Ahti , Sarkeala Tytti , Virkkunen Hanna , Hakulinen Timo
Published: March 2006

The aim of this study was to quantify the effects of separate phases of an invitational screening program on breast cancer incidence at different ages. Our database included detailed municipality‐specific information about invitations for mass‐screening for breast cancer in 267 Finnish municipalities from time period 1987–2001. The age range was 50–74. For this study, the program was divided into 7 separate phases, and those that had not been invited served as a baseline. The incidence rate was modeled using Poisson regression. To study the differences between age groups within each program phase, an interaction term between age group and phase of screening was included in the model. The modeling was done separately for localized breast cancers, nonlocalized breast cancers and all stages combined. For localized cancers, the risk compared to the noninvited increased during the first years of the 2‐year screening rounds in all age groups, and declined below the baseline during the second years. This effect was larger during the first round compared to the subsequent ones. In nonlocalized cancers, a clear incidence peak was detected only during the first year of the first round. A decreasing post screening effect was detected in nonlocalized cancers in women aged 60–69, but not in localized cancers. Cumulating over ages 50–74, extra incidence caused by regular screening in localized cancers was 5.2% if the program was continued up to age 59, and 28.0% if it continued up to age 69. Corresponding figures for nonlocalized cancers were decreases of 19.8% and 20.9%, respectively. © 2006 Wiley‐Liss, Inc.
Progressive increase of SCCA‐IgM immune complexes in cirrhotic patients is associated with development of hepatocellular carcinoma
Authors: Pontisso Patrizia , Quarta Santina , Caberlotto Cristina , Beneduce Luca , Marino Maria , Bernardinello Elisabetta , Tono Natascia , Fassina Giorgio , Cavalletto Luisa , Gatta Angelo , Chemello Liliana
Published: March 2006

About 3–4% of cirrhotic patients develop primary liver cancer every year. Specific serologic markers have not yet been identified for screening of high risk patients. The serpin squamous cell carcinoma antigen (SCCA) is overexpressed in liver cancer and circulating SCCA‐IgM complexes have been described in patients with hepatocellular carcinoma (HCC). The aim of the present study was to assess the behavior of SCCA‐IgM in relation to HCC development in patients with cirrhosis. A retrospective, longitudinal study was conducted in a cohort of prospectively followed cirrhotic patients. Two groups with similar clinical profile at presentation were studied : group A included 16 patients who developed HCC during a median follow up of 4 years; group B included 17 patients who did not develop HCC during the same time interval. Circulating SCCA‐IgM immune complexes were determined using a recently standardized ELISA assay. At presentation similar levels of SCCA‐IgM complexes [mean ± SD: 267.40 ± 382.25 U/ml vs. 249.10 ± 446.90 U/ml, p = 0.9006] and of alpha‐fetoprotein [AFP; 24.11 ± 59.04 IU/ml vs. 10.91 ± 23.34 IU/ml, p = 0.3995] were detected in group A and in group B. The increase over time (ϕ) of SCCA‐IgM, assessed within at least one year before clinical diagnosis of HCC, was remarkably higher in group A than in group B (mean ± SD = 280.05 ± 606.71 (U/ml)/year vs. −37.92 ± 95.94 (U/ml)/year, p = 0.0408), while AFP increase was not significantly different (11.89 ± 23.27 (IU/ml)/year vs. 3.67 ± 11.46 (IU/ml)/year, p = 0.2179). Receiver operating characteristic (ROC) curves were plotted for the rate of change in the levels of both markers and the diagnostic accuracy measured as AUROC was higher for SCCA‐IgM ϕ (0.821) than for AFP ϕ (0.654). In conclusion, the progressive increase of SCCA‐IgM over time was associated with liver tumor development, suggesting that monitoring the behavior of SCCA‐IgM might become useful to identify cirrhotic patients at higher risk of HCC development. © 2006 Wiley‐Liss, Inc.
Prediction of treatment outcome by cisplatin‐DNA adduct formation in patients with stage III/IV head and neck squamous cell carcinoma, treated by concurrent cisplatin‐radiation (RADPLAT)
Authors: Hoebers Frank J.P. , Pluim Dick , Verheij Marcel , Balm Alfons J.M. , Bartelink Harry , Schellens Jan H.M. , Begg Adrian C.
Published: March 2006

The purpose of our study was to test the predictive value of cisplatin‐DNA adduct levels in head and neck squamous cell carcinoma (HNSCC) patients treated with cisplatin‐radiation. Patients with advanced‐stage HNSCC were treated within a randomized trial, investigating the optimal route of cisplatin administration, concurrently with radiation. Cisplatin was administered intra‐arterially (IA, 150 mg/m2, with systemic rescue by sodium thiosulfate) or intravenously (IV, 100 mg/m2). In a subgroup, adducts were quantified in normal tissue and tumor. 32P‐postlabeling was used to quantify intrastrand guanosine–guanosine adducts (GG‐adducts) and adenosine–guanosine adducts (AG‐adducts). Adduct levels were correlated with treatment outcome. Thirty‐five patients were included (21 IV and 14 IA). At median follow‐up of 27 months, locoregional (LR) control was 75% at 1 and 70% at 2 years. Adduct levels in tumor were 4–5‐fold higher than in white blood cells (WBC) for both IA and IV treatment (p = 0.01). Adduct formation in WBC and buccal cells was higher in IV treated patients compared with IA infusion (p = 0.049 and 0.005 for GG‐adducts in WBC and buccal cells, respectively). Adducts in tumors after IA infusion were not statistically different from those after IV. A strong correlation was observed between GG‐ and AG‐adduct formation (r = 0.86, p < 0.001). Patients with higher GG adduct levels (>median) in primary tumor had significantly better disease free survival (DFS) than patients with lower (≤ median) adduct levels (p = 0.02). For overall survival (OS), a nonsignificant trend was observed, again in favor of patients with higher adduct levels (p = 0.06). In conclusion, cisplatin‐DNA adduct formation in primary tumor appears to be predictive for DFS in HNSCC. No differences were observed in intratumoral adduct levels between IA and IV treatments, despite selective infusion of high‐dose cisplatin with the IA procedure. However, systemic adduct levels (WBC and buccal cells) from IV patients were higher than in IA patients, consistent with less systemic exposure after IA administration. © 2006 Wiley‐Liss, Inc.