bluuebunny/crossref_metadata_2025 huggingface dataset:
PVA networks grafted with PDMS branches
Authors: Subramanyam Ummadisetty , Kennedy Joseph P.
Published: September 2009

We describe a simple and efficient synthesis of poly(vinyl alcohol) (PVA) networks fitted with polydimethylsiloxane (PDMS) branches (PVAnetw‐g‐PDMS). The syntheses were achieved in two steps: (1) Grafting by urethane linking PDMS carrying NCO termini (PDMS‐NCO) onto PVA fitted with a few (∼4) photoreactive acryl amide groups (PVAAA), followed by (2) Photocrosslinking the PVAAA‐g‐PDMS to PVAnetw‐g‐PDMS. The use of the binary N‐methyl‐2‐pyrrolidone/tetrahydrofuran (NMP/THF, 67/33) solvent system enabled the thermodynamically unfavorable mixing of hydrophobic PDMS branches with hydrophilic PVAAA backbones. The amphiphilic graft, PVAAA‐g‐PDMS, was characterized by 1H NMR spectroscopy, and the final graft network, PVAnetw‐g‐PDMS, by FTIR spectroscopy, DSC, and equilibrium swelling. The grafting of sufficient volumes of PDMS branches onto PVAAA yields cocontinuous hydrophilic/hydrophobic PVA/PDMS domains, whose existence was demonstrated by swelling in both water and hexanes. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5272–5277, 2009
A comprehensive investigation into “controlled/living” chain growth crosslinking copolymerization including a back to basics modeling
Authors: Poly Julien , Wilson D.James , Destarac Mathias , Taton Daniel
Published: September 2009

The mainstay of this description is a modeling of “controlled/living” chain growth crosslinking copolymerization (C/L CC) that is based on a simple equivalent kinetic scheme, resulting from assumptions consistent with an ideal C/L behavior. Analytical expressions of the double bond concentration according to reaction parameters are derived from the corresponding set of differential equations, and consideration of the respective values of the rate constants enables one to forecast the morphology of the branched polymers derived by C/L CC. The kinetic scheme is then enriched with a necessary distinction between intramolecular (cyclization) and intermolecular crosslinking which contribute to the formation of three‐dimensional structures and to the increase of molar masses, respectively. This consideration leads to a key‐equation governing C/L CC, which can be exploited in two ways. Its implicit integration coupled with a semi‐empiric methodology gives an easy access to all the characteristic magnitudes of the products at complete conversion of the double bonds. An alternative approach implying a supplementary modeling of local concentration effects enables its numerical resolution. Modeled trends and predicted characteristic values are then successfully compared with experimental data which relate to xanthate‐mediated radical CC. Specific reasons of dispersity related to the mechanism of CC are also discussed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5313–5327, 2009
Preparation of nanocomposites by reversible addition‐fragmentation chain transfer polymerization from the surface of quantum dots in miniemulsion
Authors: Esteves Ana Catarina C. , Hodge Philip , Trindade Tito , Barros‐Timmons Ana M. M. V.
Published: September 2009

Herein, we report the synthesis of quantum dots (QDs)/polymer nanocomposites by reversible addition‐fragmentation chain transfer (RAFT) polymerization in miniemulsions using a grafting from approach. First, the surfaces of CdS and CdSe QDs were functionalized using a chain transfer agent, a trisalkylphosphine oxide incorporating 4‐cyano‐4‐(thiobenzoylsulfanyl)pentanoic acid moieties. Using a free radical initiator (AIBN) to activate the RAFT process, a polystyrene (PS) block was grafted from the surface of the QDs. Quantum confinement effects were identified for the nanocomposite obtained, so attesting to the integrity of the QDs after the polymerization. Free PS chains were also present in the final nanocomposite, indicating that the RAFT polymerization from the surface of the QDs was accompanied by conventional free radical polymerization. After isolating the nanocomposite particles, a second poly(n‐butyl acrylate) block was tentatively grown from the initial PS block. The first results indicated a successful polymerization of the second polymer and show the potential of the current strategy to prepare block copolymers from the surface of the RAFT‐modified QDs. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5367–5377, 2009
Near‐infrared electrochromic poly(aryl ether)s based on isolated electroactive tetraphenyl‐p‐phenylenediamine moieties
Authors: Liou Guey‐Sheng , Yen Hung‐Ju , Chiang Ming‐Che
Published: September 2009

A series of near‐infrared (NIR) electrochromic aromatic poly(aryl ether)s containing N,N,N′,N′‐tetraphenyl‐p‐phenylenediamine (TPPA) moieties in the backbone were prepared from the high‐temperature polycondensation reactions of a biphenol monomer, 2,5‐bis(diphenylamino)hydroquinone, with difluoro compounds. The obtained polymers were readily soluble in many organic solvents and showed useful levels of thermal stability associated with high glass‐transition temperatures (182–205 °C) and high char yields (higher than 40% at 800 °C in nitrogen). The polymer films showed reversible electrochemical oxidation with high contrast ratio both in the visible range and NIR region, and also exhibited high coloration efficiency (CE), low switching time, and stability for electrochromic operation. The polyether TPPA‐a thin film revealed good CE in visible (CE = 217 cm2/C) and NIR (CE = 192 cm2/C) region with reversible electroactive stability (over 500 times within 5% loss relative to its initial injected charge). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5378–5385, 2009
Aqueous RAFT polymerization of 2‐aminoethyl methacrylate to produce well‐defined, primary amine functional homo‐ and copolymers
Authors: Alidedeoglu Alp H. , York Adam W. , McCormick Charles L. , Morgan Sarah E.
Published: September 2009

We report the direct homopolymerization and block copolymerization of 2‐aminoethyl methacrylate (AEMA) via aqueous reversible addition‐fragmentation chain transfer (RAFT) polymerization. The controlled “living” polymerization of AEMA was carried out directly in aqueous buffer using 4‐cyanopentanoic acid dithiobenzoate (CTP) as the chain transfer agent (CTA), and 2,2′‐azobis(2‐imidazolinylpropane) dihydrochloride (VA‐044) as the initiator at 50 °C. The controlled “living” character of the polymerization was verified with pseudo‐first order kinetic plots, a linear increase of the molecular weight with conversion, and low polydispersities (PDIs) (<1.2). In addition, well‐defined copolymers of poly(AEMA‐b‐HPMA) have been prepared through chain extension of poly(AEMA) macroCTA with N‐(2‐hydroxypropyl)methacrylamide (HPMA) in water. It is shown that the macroCTA can be extended in a controlled fashion resulting in near monodisperse block copolymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5405–5415, 2009
Synthesis, characterization, and photoresponsive behavior of new azobenzene‐containing polyethers
Authors: Peris Sergio , Tylkowski Bartosz , Carles Ronda Joan , Garcia‐Valls Ricard , Reina José Antonio , Giamberini Marta
Published: September 2009

Two new polyethers, bearing azobenzene moiety in the side chain, were synthesized in excellent yields by means of anionic polymerization of 4‐glycidyloxyazobenzene and 4‐cyano‐4′‐glycidyloxyazobenzene (leading to azo‐P1 and azo‐P2 polymers, respectively) with the system polyiminophosphazene base t‐Bu‐P4/3,5‐di‐tert‐butylphenol as initiator. The polymers were characterized with respect to their molecular weights, structure, and calorimetric features. The polyether bearing cyanoazobenzene group in the side chain was found to exhibit nematic phase up to 200 °C. E–Z isomerization of both polymers in tetrahydrofuran solution, after irradiating with UV light at 364 nm for 15 min, was investigated by means of UV–visible absorption spectroscopy. In the case of glycidylic monomers as well as the resulting polymers, E–Z isomerization was also investigated by means of 1H NMR, by direct irradiation in the NMR probe in deuterated 1,1,2,2‐tetrachloroethane solution. By this technique, in the case of 4‐cyano‐4′‐glycidyloxyazobenzene, it was found that irradiation led to a photostationary state corresponding to an amount of Z isomer equal to 25%. For azo‐P1 polymer, Z–E or “reverse” isomerization was investigated at 60, 70, or 80 °C directly in the NMR probe; as expected, the process followed a first‐order rate law. The kinetic constants as well as the activation energy for the process were determined in this temperature range. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5426–5436, 2009
Michael addition for crosslinking of poly(caprolactone)s
Authors: Ozturk Gozde , Long Timothy E.
Published: September 2009

Poly(caprolactone) (PCL) networks have received significant attention in the literature because of many emerging potential applications as biodegradable materials. In this study, the Michael addition reaction was used for the first time to synthesize biodegradable networks using crosslinking of acetoacetate‐functionalized PCL (PCL bisAcAc) oligomers with neopentyl glycol diacrylate. Hydroxyl‐terminated PCL telechelic oligomers with number‐average molecular weights ranging from 1000 to 4000 g/mol were quantitatively functionalized with acetoacetate groups using transacetoacetylation. In addition to difunctional PCL oligomers, hydroxyl‐terminated trifunctional star‐shaped PCL oligomers were functionalized with acetoacetate groups. Derivatization of the terminal hydroxyl groups with acetoacetate groups was confirmed using FTIR spectroscopy, 1H NMR spectroscopy, mass spectrometry, and base titration of hydroxyl end groups. PCL bisAcAc precursors were reacted with neopentyl glycol diacrylate in the presence of an organic base at room temperature. The crosslinking reactions yielded networks with high gel contents (>85%). The thermomechanical properties of the networks were analyzed to investigate the influence of molecular weight between crosslink points. The glass transition and the extent of crystallinity of the PCL networks were dependent on the molecular weight of the PCL segment. Dynamic mechanical analysis indicated that the plateau modulus of the networks was dependent on the molecular weight of PCL, which was related to the crosslink density of the networks. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5437–5447, 2009
Synthesis of gradient copolymers with complexing groups by RAFT polymerization and their solubility in supercritical CO2
Authors: Ribaut Tiphaine , Lacroix‐Desmazes Patrick , Fournel Bruno , Sarrade Stéphane
Published: September 2009

We report the synthesis of new gradient fluorinated copolymers with complexing groups and soluble in supercritical carbon dioxide (scCO2). Poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate‐co‐acetoacetoxyethyl methacrylate) (poly(FDA‐co‐AAEM)) and poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate‐co‐vinylbenzylphosphonic acid diethylester) (poly(FDA‐co‐VBPDE)) gradient copolymers were synthesized by reversible addition fragmentation chain transfer polymerization in α,α,α‐trifluorotoluene. Poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate‐co‐vinylbenzylphosphonic diacid) (poly(FDA‐co‐VBPDA)) gradient copolymer was efficiently obtained by cleavage of the phosphonic ester groups of poly(FDA‐co‐VBPDE). The cloud points of these gradient copolymers in dense CO2 were measured in a variable volume view cell at temperatures between 25 and 65 °C. The gradient copolymers show very good solubility in compressed CO2 with the decreasing order: poly(FDA‐co‐AAEM) ≈ poly(FDA‐co‐VBPDE) > poly(FDA‐co‐VBPDA). Following a green chemistry strategy, poly(FDA‐co‐AAEM) gradient copolymer was successfully synthesized in scCO2 with a good control over number‐average molecular weight and composition. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5448–5460, 2009
Photopolymerization of vinyl ether networks using an iodonium initiator—The role of photosensitizers
Authors: Cook Wayne D. , Chen Shaohua , Chen Fei , Kahveci Muhammet U. , Yagci Yusuf
Published: September 2009

Photo‐differential scanning calorimetry (photo‐DSC) and UV‐visible spectrometry were used to investigate the photocuring kinetics of visible light initiated cationic photopolymerization of triethyleneglycol divinyl ether with a diphenyl iodonium salt and three photosensitizers, 1‐chloro‐4‐propoxy‐9H‐thioxanthen‐9‐one (CPTXO), acridine orange (AO), and camphorquinone (CQ). Although all photosensitizers were effective in causing photopolymerization, CPTXO and AO photo‐reacted during the irradiation; whereas CQ was not significantly consumed during the timescale of the photo‐DSC experiment. This difference in photo‐reactivity has not been reported previously, and indicates that the reaction of the iodonium ion with CPTXO and AO results in the formation of the photosensitizer radical cation, whereas the CQ mechanism involves the reduction of the CQ excited state to a ketyl radical by a H‐donor (monomer) followed by the oxidation of the ketyl radical by the iodonium salt and thus regeneration of the CQ. For the CPTXO and AO systems, the photopolymerization rate was retarded by a radical inhibitor but the CQ system was unaffected, which confirms that different mechanisms are involved. The cure rate was found to be proportional to the concentrations of CPTXO and CQ but appeared to follow an approximately square root dependence on the AO concentration. Mechanisms to explain these differences were presented. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5474–5487, 2009
Synthesis and optoelectronic properties of alternating benzofuran/terfluorene copolymer with stable blue emission
Authors: Zhang Haichang , Guo Erqian , Fang Yujie , Ren Peihua , Yang Wenjun
Published: September 2009

The solution processable alternating benzofuran/terfluorene copolymer bearing side oxadiazole groups (PBF‐OXD) was synthesized and its optoelectronic properties and color stability were investigated. Electron‐deficient and stereohindered oxadiazole units were used as pendent groups to compensate for the poor electron‐transporting ability of a p‐type polymer backbone, to depress the intermolecular π‐stacking, and to improve solubility while retaining polymer blue emission. PBF‐OXD showed a glass transition at 135 °C and an onset decomposition temperature of ∼345 °C. A simple EL device, with the configuration of ITO/PEDOT:PSS/PBF‐OXD/Ba/Al, displayed a stable blue emission (λmax = 434 nm), good color purity (full width half‐maximum = 59 nm), maximum brightness of 1400 cd/m2, and a maximum luminance efficiency of 0.95 cd/A. The PL and EL spectra changed slightly on annealing and on increasing the applied voltage. These results show that the as‐synthesized copolymer PBF‐OXD had integrated respective functions of its different building blocks and exhibited good thermal and color stability with improved EL performance. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5488–5497, 2009
Low bandgap π‐conjugated copolymers based on fused thiophenes and benzothiadiazole: Synthesis and structure‐property relationship study
Authors: Zhang Shiming , Guo Yunlong , Fan Haijun , Liu Yao , Chen Hsiang‐Yu , Yang Guanwen , Zhan Xiaowei , Liu Yunqi , Li Yongfang , Yang Yang
Published: September 2009

A series of low bandgap conjugated polymers consisting of benzothiadiazole alternating with dithienothiophene (DTT) or dithienopyrrole (DTP) unit with or without 3‐alkylthiophene bridge have been synthesized. Effect of the fused rings and 3‐alkylthiophene bridge on the thermal, optical, electrochemical, charge transport, and photovoltaic properties of these polymers have been investigated. These polymers show broad absorption extending from 300 to 1000 nm with optical bandgaps as low as 1.2 eV; the details of which can be varied either by incorporating 3‐alkylthiophene bridge or by replacing DTT with DTP. The LUMO levels (−2.9 to −3.3 eV) are essentially unaffected by the specific choice of donor moiety, whereas the HOMO levels (−4.6 to −5.6 eV) are more sensitive to the choice of donor. The DTT and DTP polymers with 3‐alkylthiophene bridge were found to exhibit hole mobilities of 8 × 10−5 and 3 × 10−2 cm2 V−1 s−1, respectively, in top‐contact organic field‐effect transistors. Power conversion efficiencies in the range 0.17–0.43% were obtained under simulated AM 1.5, 100 mW cm−2 irradiation for polymer solar cells using the DTT and DTP‐based polymers with 3‐alkylthiophene bridge as donor and fullerene derivatives as acceptor. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5498–5508, 2009
Selective 17‐β‐estradiol molecular imprinting
Authors: Farber Shimon , Green Bernard S. , Domb Abraham J.
Published: September 2009

An efficient novel method for the synthesis of a covalent molecularly imprinted polymer (MIP) highly specific to β‐estradiol have been developed. MIP prepared by both covalent and non covalent techniques, demonstrated high selectivity toward β‐estradiol. MIPs were synthesized by radical polymerization of 17‐β‐estradiol 4‐vinyl‐benzene carboxyl or sulfonyl esters used as covalent functional monomers, methacrylic acid as noncovalent functional monomer, ethylene glycol dimethacrylate as crosslinking agent, and acetonitrile as swelling and porogenic component. Almost 35% (w/w) of 17‐β‐estradiol was successfully removed from the polymer network by basic hydrolysis. The binding ability of MIP was 10.73 μg/mg MIP following removal of 17‐β‐estradiol in the 2 mg/mL β‐estradiol solution. Selective rebinding of β‐estradiol toward MIP was tested in the presence of competitive binders including estrone, 19‐nortestosterone, epiandrosterone, and cholesterol. Estrone having closest similar chemical structure to β‐estradiol exhibited only 0.6 μg/mg MIP competitive binding, being exposed to equivalent concentrations. Moreover, other competitive steroids demonstrated negligible affinity toward MIP indicating high selectivity of novel MIP system toward β‐estradiol. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5534–5542, 2009
New efficient reaction media for SET‐LRP produced from binary mixtures of organic solvents and H2O
Authors: Nguyen Nga H. , Rosen Brad M. , Jiang Xuan , Fleischmann Sven , Percec Virgil
Published: September 2009

SET‐LRP is mediated by a combination of solvent and ligand that promotes disproportionation of Cu(I)X into Cu(0) and Cu(II)X2. Therefore, the diversity of solvents suitable for SET‐LRP is limited. SET‐LRP of MA in a library of solvents with different equilibrium constants for disproportionation of Cu(I)X such as DMSO, DMF, DMAC, EC, PC, EtOH, MeOH, methoxyethanol, NMP, acetone and in their binary mixtures with H2O was examined. H2O exhibits the highest equilibrium constant for disproportionation of Cu(I)X. The apparent rate constant of the polymerization exhibits a linear increase with the addition of H2O. This is consistent with higher equilibrium constants for disproportionation generated by addition of H2O to organic solvents. Furthermore, with the exception of alcohols and carbonates, the rate constant of polymerization in binary mixtures could be correlated with the Dimroth‐Reichardt solvent polarity parameter. This is consistent with the single‐electron transfer mechanism proposed for SET‐LRP that involves a polar transition state. These experiments demonstrate that the use of binary mixtures of solvents with H2O provides a new, simple and efficient method for the elaboration of a large diversity of reaction media that are suitable for SET‐LRP even when one of the two solvents does not mediate disproportionation of Cu(I)X. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5577–5590, 2009
Prediction of yield and long‐term failure of oriented polypropylene: Kinetics and anisotropy
Authors: van Erp Tim B. , Reynolds Chris T. , Peijs Ton , van Dommelen Johannes A. W. , Govaert Leon E.
Published: September 2009

The time‐dependent yield and failure behavior of off‐axis loaded uniaxially oriented polypropylene tape is investigated. The yield and failure behavior is described with an anisotropic viscoplastic model. A viscoplastic flow rule is used with an equivalent stress, based on Hill's anisotropic yield criterion, and the Eyring flow theory combined with a critical equivalent strain definition. This model is based on factorization of the rate and draw ratio dependence and is capable of quantitatively predicting the rate, angle and draw ratio dependence of the yield stress as well as time‐to‐failure in various off‐axis tensile loading conditions characterized solely from the transverse direction. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2026–2035, 2009
Enhancement in solubility and conductivity of polyaniline with lignosulfonate modified carbon nanotube
Authors: Dong Jin‐Qiao , Shen Qing
Published: September 2009

An organic solvent soluble and high electrical conductivity, for example, 55.43 S/cm, polyaniline (PANI), was synthesized by a novel method. In this two steps process, a noncovalent approach was initially developed by functionalization of multiwalled carbon nanotubes (MWNTs) using calcium lignosulfonate (LsCa) via self‐assembly to result MWNTs‐LsCa. Then, the MWNT‐LsCa was employed as a template to lead anilinium monomers directly aligned on the surface to start the polymerization of PANI. The noncovalent modification of MWNTs avoided their agglomeration effectively to allow them doped in PANI at the molecular level. The obtained novel PANI/MWNTs‐LsCa presented excellent solubility and high conductivity. The recorded scanning electron microscopy photographs revealed that the MWNTs‐LsCa was wrapped with PANI chains that caused the crystal orientation improvement. In this article, a related scheme on resulting in the high conductivity of PANI/MWNTs‐LsCa was showed and described. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2036–2046, 2009
Some Examples of Temperature and Time Resolved Studies of the Dehydration and Hydration Behavior of Zeolites and Clathrates
Authors: Depmeier Wulf
Published: September 2009

The prominent role of X‐ray powder diffraction (XRPD) for the study of the dehydration and hydration behavior of microporous zeolites and clathrates can be documented by several typical examples taken from the literature. The importance of various interactions, in particular water‐framework, water‐extra‐framework cations, framework‐extra‐framework cations, and water‐water is discussed. However, it is emphasized that XRPD has its limitations, especially when species are disordered, and should be complemented as far as possible by the determination of bulk properties, and also by various appropriate spectroscopic methods.
Fast XRD2 Microdiffraction with Focusing X‐Ray Microlenses
Authors: Berthold Christoph , Bjeoumikhov Aniouar , Brügemann Lutz
Published: September 2009

The advantages using specially designed X‐ray‐polycapillary microlenses with spot sizes of 50 μm to 200 μm in a commercially available BRUKER D8 DISCOVER GADDS XRD2‐microdiffractometer with a standard sealed X‐ray tube instead of a microfocus source are shown and compared to commercially available pin hole collimators or monocapillary optics.

The application of a focusing X‐ray microlens instead of a monocapillary optic with similar spot size leads to an increase of the primary beam flux by a factor of approximately 10 to larger than 100 depending on the additional pinhole used at the exit of the microlens. This additional pinhole can be used to optimize the beam geometry for a better peak profile without additional changes on the setup. Therefore the use of a focusing X‐ray microlens instead of a mono capillary optic reduces the measurement time by at least a factor of 10. A factor up to 200 is possible by simple changing the diameter of the exit pinhole – for the price of a wider peak profile. Due to the similar housing the focusing X‐ray microlens fits in the standard collimator support enabling switching between collimators, mono‐capillaries and the microlens without realignment. This is why no time consuming modification of the microdiffractometer is needed.
X‐Ray Diffractometry with Low Power Microfocus Sources – New Possibilities in the Lab
Authors: Wiesmann Jörg , Graf Jürgen , Hoffmann Christian , Hembd Alexandra , Michaelsen Carsten , Yang Ning , Cordes Holger , He Bob , Preckwinkel Uwe , Erlacher Kurt
Published: September 2009

Results from a new type of stationary microfocusing sealed tube X‐ray source will be presented here. Measurements obtained with the new low maintenance, high brilliance microfocus source IμS™ equipped with different 2‐dimensional beam shaping multilayer optics are shown. A comparison of the IμS source with typical sealed tube fine focus systems shows data of outstanding quality achieved in diffractometry applications using a 2‐dimensional detector. A large improvement in intensity (by a factor of about 16) was observed. Very promising results were achieved when measuring powders in transmission geometry using the IμS. With this way of focusing on the detector, better crystallite statistics and better resolution were provided. Intensity gain factors in the range of 100 were possible with some applications. For small angle scattering a factor of five was observed when using an IμS with optics for a parallel beam in comparison to a typical sealed tube instrument.
Therapeutic bronchoscopy in a child with sand aspiration and respiratory failure from near drowning—case report and literature review
Authors: Kapur N. , Slater A. , McEniery J. , Greer M.L. , Masters I.B. , Chang A.B.
Published: September 2009

Foreign matter aspiration occurs relatively commonly in drowning and near‐drowning events. In most cases, stomach contents are aspirated. Sand aspiration rarely occurs and there are no reported cases in children with near drowning. Limited data are available on clinical presentation and management of sand aspiration with accidental burial. We report a 3‐year‐old boy who nearly drowned while swimming in brackish waters and was found face down in sand. Sand aspiration was suspected when the child continued to have persistent wheezing and high ventilatory requirement despite intensive bronchodilator and corticosteroids therapy with an inability to wean after 4 days post‐near‐drowning event. Radiology was non‐specific in the absence of sand bronchogram. Presence of sand in the airways was confirmed when a bronchoscopy was undertaken and sand seen in the bronchoalveolar lavage fluid. Sequential lung washing followed by exogenous surfactant administration (3 ml/kg) was undertaken and lead to significant improvement such that within 12 hr post‐therapeutic lavage, his ventilatory requirements reduced substantially. The child was extubated 4 days post‐lavage and on review 2 months post‐event, was clinically well with airway resistance within normal predicted values measured on forced oscillatory spirometry (IOS). Pediatr Pulmonol. 2009; 44:1043–1047. ©2009 Wiley‐Liss, Inc.
Leukotriene receptor antagonist in the treatment of childhood allergic rhinitis—a randomized placebo‐controlled study
Authors: Li Albert M. , Abdullah Victor J. , Tsen Chui S. , Au Chun T. , Lam Hugh S. , So Hung K. , Chan Michael H.M. , Leung Alex W.K. , Chan Iris H.S. , Lam Christopher W.K. , Ng Pak C.
Published: September 2009

Objective

This study was designed to assess the hypothesis that leukotriene receptor antagonists (LTRAs) would provide additional symptom relief in asthmatic children with persistent AR already taking regular antihistamine. The effects of 16‐week treatment of LTRA in addition to fexofenadine (FEX) on persistent AR in asthmatic children were examined.

Study Design

Consecutive children with stable asthma and persistent AR were invited in this randomized, double‐blind, placebo‐controlled study. After a 2‐week run‐in period in which subjects were given FEX alone, they were randomly assigned to take LTRA or placebo in addition to FEX for 16 weeks, followed by 8 weeks of follow‐up phase with FEX taken alone. Symptom scoring, rhinoscopy, acoustic rhinometry, spirometry, nasal secretion extraction and blood taking for IL‐4 and IL‐13 analysis were performed after a 2‐week run‐in and at the end of treatment.

Results

Forty‐four subjects with a median (IQR) age of 12.2 (10.1–14.1) years were recruited. At week 4 of treatment, the between‐group differences in the mean changes of daytime sneezing score (mean difference (95% CI) = −0.35 (−0.59, −0.12), P = 0.004), nighttime sneezing score (mean difference (95% CI) = −0.37 (−0.62, −0.11), P = 0.007) and daytime composite score (mean difference (95% CI) = −1.08 (−1.92, −0.25), P = 0.013) were significant. Acoustic rhinometry also demonstrated a nearly significant difference in nasal volume change between groups at 16 weeks of treatment (mean difference (95% CI) = 0.572 (0.090–1.054), P = 0.021). IL‐4 and IL‐13 were not detected in the majority of nasal secretion or serum samples.

Conclusions

Additional LTRA provided a more rapid relief on sneezing at the 4‐week time point. This combination therapy also maintained a greater nasal volume and this might translate to lesser nasal congestion. Pediatr Pulmonol. 2009; 44:1085–1092. ©2009 Wiley‐Liss, Inc.
Identity crisis: on the problem of namespace design for ID‐PKC and MANETs
Authors: Balfe Shane , McDonald Andrew D. , Paterson Kenneth G. , Phillips Helen
Published: September 2009

In this paper, we explore the ‘interface’ between identity‐based public key cryptography (ID‐PKC) and mobilead hocnetworks (MANETs). In particular, we examine the problem of naming and namespace design in an identity‐based key infrastructure (IKI). We examine the potential impact that different types of identifiers may have on the utility ofad hocnetworks where an IKI provides the underlying key infrastructure. We also highlight a number of open problems inherent in extending namespaces to allow inter‐operability amongst heterogeneous trust domains. Copyright © 2009 John Wiley & Sons, Ltd.
Nachweiskonzepte zur Bemessung ermüdungsbeanspruchter Bauteile unter Berücksichtigung von Schweißnahtnachbehandlungsverfahren durch höherfrequentes Hämmern
Authors: Günther Hans‐Peter , Kuhlmann Ulrike
Published: September 2009

Die Anwendung von höherfrequenten Hämmerverfahren zur Erhöhung der Ermüdungsfestigkeit von dynamisch beanspruchten Bauteilen gewinnt zunehmend an Bedeutung. Dies hängt zum einen damit zusammen, dass bei Neukonstruktionen durch den Einsatz von höherfesten Stählen die Frage der Materialermüdung verstärkt die Bauteilauslegung bestimmt, und zum anderen, dass bei vielen bestehenden Bauwerken vermehrt Maßnahmen zur Verlängerung der Restlebensdauer erforderlich werden. Die Anwendung von Schweißnahtnachbehandlungsverfahren in Form von höherfrequentem Hämmern stellt hierfür eine geeignete Maßnahme dar, die Ermüdungsfestigkeit von Neukonstruktionen zu erhöhen bzw. die Restlebensdauer bestehender Anlagen zu verlängern. Eine zuverlässige baupraktische Anwendung setzt jedoch die Existenz anerkannter Regeln für die Bemessung voraus, wie auch eine darauf abgestimmte Vorgehensweise für die Ausführung. Der vorliegende Beitrag widmet sich vor allem der Darstellung bisher existierender Nachweiskonzepte für die Bemessung ermüdungsbeanspruchter Bauteile bei Anwendung von Schweißnahtnachbehandlungsverfahren in Form von höherfrequentem Hämmern.

Fatigue design concepts for post‐weld treated joints improved by high frequency hammer peening methods.

Post‐weld improvement methods have been widely investigated and have in most cases been found to give substantial increases in the fatigue strength. Nowadays, there is an increasing interest in using such methods in order to either improve the fatigue resistance of new structures built e.g. by high strength steel and/or to enlarge the lifetime of existing structures suffering from fatigue problems. With regard to this, post‐weld improvement using high frequency hammer peening methods lately showed very good and promising results in combination with simple operation conditions.

However, the successful application of post‐weld improvement methods always requires the existence of profound fatigue design concepts as well as relevant execution and quality standards. The following paper refers predominately to the first aspect, in trying to summarise and compare existing design concepts and their application range for high frequency hammer peening methods.
HiFIT – Technische Entwicklung und Anwendung
Authors: Telljohann Gerd , Dannemeyer Sven
Published: September 2009

Das Verbundprojekt REFRESH bot in den vergangenen drei Jahren eine ideale Plattform für die theoretische und experimentelle Weiterentwicklung des HiFIT (high frequency impact treatment)‐Verfahrens. So konnten sowohl die Behandlungsparameter an umfangreichen Schweißproben optimiert als auch ein industrietaugliches Gerätedesign unter Einbeziehung zahlreicher Anwendungsfälle aus der Praxis der Industriepartner entwickelt werden. Effizienz, Ergonomie und die Qualitätssicherung standen bei der Entwicklung im Vordergrund. Die Beurteilung der Anwendbarkeit des Verfahrens und die Anwendung selbst sollten im Sinne einer allgemeinen Qualitätssicherung und zur Quantifizierung des zu erwartenden Behandlungserfolgs von geschultem Personal durchgeführt werden. Letzteres gilt nicht nur im Speziellen für das HiFIT‐Verfahren, sondern generell für alle Nachbehandlungsverfahren. Hinter dem Markennamen HiFIT steht ein ganzheitliches Lösungskonzept mit rechnerischen Analysetools, Nachbehandlungswerkzeugen, Schulung und Consulting zur effizienten Steigerung der Betriebsfestigkeit neuer und bereits im Einsatz befindlicher Schweißkonstruktionen.

HiFIT – Technical development and application.

In the past three years the HiFIT technology for application on welded parts has been investigated in the REFRESH project. Many treatment parameters have been tested. Using prototype devices a lot of experience has been gained by treatment of several parts in cooperation with the project partners. The design of the HiFIT device is optimized for industrial application where efficiency, ergonomics and quality assurance are the main topics. An application benchmark of HiFIT and the treatment should be done only by specially trained employees. This restriction is not only HiFIT specific. The trademark HiFIT means a solution for improvement of fatigue strength of new and cyclic pre‐damaged welded structures. The solution contains assessment of fatigue strength, treatment devices, training and consulting.
Anwendung eines hochfrequenten Hämmerverfahrens zur Optimierung von geschweißten Motorbauteilen bei MAN Diesel SE
Authors: Kern Annekathrin , Pinkernell Dietmar
Published: September 2009

Das hochfrequente Hämmerverfahren HiFIT (high frequency impact treatment) zur Lebensdauerverlängerung bestehender und neuer Stahlschweißkonstruktionen konnte bei MAN Diesel SE erfolgreich eingeführt werden. Ein wesentlicher Arbeitsschritt war dabei die Entwicklung eines neuartigen Bemessungskonzeptes auf Basis bruchmechanischer Methoden. Zum einen wurde das Nachbehandlungsverfahren in der Neukonstruktion einer Ölwanne eingesetzt, um die nötigen Sicherheitsfaktoren gegen Dauerbruch darstellen zu können. Zum anderen wurde es nachträglich eingeführt, nachdem durch Spannungsmessungen an einem Fundamentrahmen die Notwendigkeit einer Verbesserung deutlich wurde. Die Anwendungsbeispiele werden im folgenden Beitrag vorgestellt. In beiden Fällen wurde durch das hochfrequente Hämmerverfahren die Dauerfestigkeit erreicht und durch Betriebserfahrung bestätigt. Damit konnte ein weiterer Schritt in Richtung eines betriebssicheren Leichtbaus von Schweißkonstruktionen erfolgreich gegangen werden.

Implementation of high‐frequent hammer‐peening as an optimisation step for welded engine components at MAN Diesel SE.

The high‐frequent hammer‐peening called HiFIT (high frequency impact treatment) was introduced successfully at MAN Diesel SE. As an essential step, a new fatigue assessment procedure based on fracture mechanics was developed. On one hand, the after‐treatment procedure was used in the design phase of an oil pan to achieve sufficient safety factors against fatigue fracture. On the other hand, it was adopted in an existing design of a foundation frame because in‐situ measurements have revealed the need for improvement. This paper represents the both examples of application. In both cases, the fatigue requirements have been fulfilled with the high‐frequent hammer‐peening and are approved by field‐experience. Thus, another step towards a reliable light‐weight‐design of welded components could be taken
Versuche und Anwendung hochfrequenter Hämmerverfahren als Schweißnahtnachbehandlung
Authors: Smida Michael , Senk Burkhard , Strähuber Vitus
Published: September 2009

Die Lebensdauer von dynamisch belasteten Bauteilen aus Stahl stellt ein entscheidendes Qualitätsmerkmal von Produkten der Stahlbau Firmen dar.

Der Einsatz höherfrequenter Hämmerverfahren, im Besonderen des UIT oder HiFIT‐Verfahrens, als lebensdauerverlängernde Maßnahme von ermüdungsbeanspruchten Schweißverbindungen wurde im Rahmen des REFRESH‐Forschungsprojekts erstmals wissenschaftlich untersucht.

Einsatz und Wirksamkeit der Verfahren wurde von den am Projekt beteiligten Firmen an ausgeführten Bauteilen untersucht. Die Erkenntnisse aus Versuchen und praktischer Anwendung der Firmen Schachtbau Nordhausen und Maurer Söhne werden im folgenden Artikel geschildert.

Tests and application of high frequency peening as a post weld treatment method.

The fatigue life of dynamic loaded steel construction elements is an influential quality characteristic for products of steel fabricators.

The application of high frequency peening, especially the UIT (ultrasonic impact treatment) or the HiFIT (high frequency impact treatment) as a method to extend the fatigue life of welded connections, has been investigated in course of the research project called REFRESH for the first time.

The practical application and the effectiveness of high frequency peening at finished building components have been examined by building companies which are concerned to the research project. The present paper describes the tests and the practical application of the companies Schachtbau Nordhausen and Maurer Söhne.
A novel zebrafish mutant with wavy‐notochord: An effective biological index for monitoring the copper pollution of water from natural resources
Authors: Chen Yau‐Hung , Lin Ji‐Sheng
Published: September 2009

We identified a novel zebrafish mutant that has wavy‐notochord phenotypes, such as severely twisted notochord and posterior malformations, but has normal melanocytes. Histological evidences showed that proliferating vacuolar cells extended their growth to the muscle region, and consequently caused the wavy‐notochord phenotypes. Interestingly, those malformations can be greatly reversed by exposure with copper, suggesting that copper plays an important role on wavy‐notochord phenotypes. In addition, after long‐term copper exposure, the surviving larvae derived from wavy‐notochord mutants displayed bone malformations, such as twisted axial skeleton and osteophyte. These phenotypic changes and molecular evidences of wavy‐notochord mutants are highly similar to those embryos whose lysyl oxidases activities have been inactivated. Taken together, we propose that (i) the putative mutated genes of this wavy‐notochord mutant might be highly associated with the lysyl oxidase genes in zebrafish; and (ii) this fish model is an effective tool for monitoring copper pollution of water from natural resources. © 2009 Wiley Periodicals, Inc. Environ Toxicol 26: 103–109, 2011.
Use of ultrasound pattern recognition by expert operators to identify borderline ovarian tumors: a study of diagnostic performance and interobserver agreement
Authors: Yazbek J. , Ameye L. , Timmerman D. , Testa A. C. , Valentin L. , Holland T. K. , Van Holsbeke C. , Jurkovic D.
Published: September 2009

Objective

To assess the accuracy and reproducibility of ultrasound ‘pattern recognition’ for the diagnosis of borderline ovarian tumors by asking experienced ultrasound operators to evaluate representative images of different types of adnexal tumor.

Methods

Digitally stored static two‐dimensional B‐mode images of representative cases of benign, borderline and invasive malignant ovarian tumors were independently assessed by three expert sonologists who had not performed the original real‐time ultrasound examination. The outcome measures included diagnostic accuracy and interobserver agreement in the diagnosis of benign, borderline or invasive malignant ovarian tumors.

Results

One hundred and sixty‐six cases were included in the final data analysis. A correct classification was made by all three experts in 83% of the primary invasive cancers, 76% of the benign masses and in 44% of the borderline malignant tumors (P < 0.01). The experts showed a tendency to misclassify borderline tumors as benign rather than primary invasive (ratio of 8 : 1 for Expert A, 4 : 1 for B and 6 : 1 for C). The interobserver agreement between any two experts was very good when they were tested for their ability to discriminate between invasive and non‐invasive (benign and borderline) ovarian tumors (Cohen's kappa 0.85–0.88), but poorer for the discrimination between malignant (invasive and borderline) and benign tumors (kappa 0.70–0.78).

Conclusions

The accuracy of ultrasound diagnosis of borderline tumors is lower in comparison with benign and invasive malignant lesions. The diagnostic performance and interobserver agreement are better when the outcomes are dichotomized into non‐invasive and invasive malignant lesions, as opposed to the traditional diagnosis of benign and malignant tumors. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Time Delay Embedding Increases Estimation Precision of Models of Intraindividual Variability
Authors: von Oertzen Timo , Boker Steven M.
Published: September 2009

This paper investigates the precision of parameters estimated from local samples of time dependent functions. We find that time delay embedding, i.e., structuring data prior to analysis by constructing a data matrix of overlapping samples, increases the precision of parameter estimates and in turn statistical power compared to standard independent rows of panel data. We show that the reason for this effect is that the sign of estimation bias depends on the position of a misplaced data point if there is no a priori knowledge about initial conditions of the time dependent function. Hence, we reason that the advantage of time delayed embedding is likely to hold true for a wide variety of functions. We support these conclusions both by mathematical analysis and two simulations.
Regulation of HMGCoA Reductase Activity by Policosanol and Octacosadienol, a New Synthetic Analogue of Octacosanol
Authors: Oliaro‐Bosso Simonetta , Calcio Gaudino Emanuela , Mantegna Stefano , Giraudo Enrico , Meda Claudia , Viola Franca , Cravotto Giancarlo
Published: September 2009

Octacosa‐10,19‐dien‐1‐ol is a newly synthesized long‐chain alcohol, an unsaturated analogue of 1‐octacosanol, the major component of policosanol, the purified natural mixture of different higher aliphatic alcohols obtained from sugarcane wax. Our efficient synthetic protocol (five steps with 50% overall yield) is well suited for gram scale preparations and a rapid generation of analogues with different degrees of unsaturation. Beneficial effects of policosanol in the prevention of atherosclerosis and thromboembolic disorders have been reported and related to the inhibition of sterol biosynthesis possibly by the regulation of the activity of HMGCoA reductase mediated by AMP‐dependent kinase AMPK. We have compared the effect of octacosadienol and policosanol on the regulation of HMGCoA reductase in HUVEC and HepG2 human hepatoma cells. Octacosadienol was as effective as policosanol in inhibiting the upregulation of HMGCoA reductase, in inducing the phosphorylation of AMPK and in downregulating the HMGCoA reductase mRNA.
Temporal lobe functional activity and connectivity in young adult APOE ɛ4 carriers
Authors: Dennis Nancy A. , Browndyke Jeffrey N. , Stokes Jared , Need Anna , Burke James R. , Welsh‐Bohmer Kathleen A. , Cabeza Roberto
Published: September 2009

Background

We sought to determine if the APOE ε4 allele influences both the functional activation and connectivity of the medial temporal lobes (MTLs) during successful memory encoding in young adults.

Methods

Twenty‐four healthy young adults, i.e., 12 carriers and 12 noncarriers of the APOE ε4 allele, were scanned in a subsequent‐memory paradigm, using event‐related functional magnetic resonance imaging. The neuroanatomic correlates of successful encoding were measured as greater neural activity for subsequently remembered versus forgotten task items, or in short, encoding success activity (ESA). Group differences in ESA within the MTLs, as well as whole‐brain functional connectivity with the MTLs, were assessed.

Results

In the absence of demographic or performance differences, APOE ε4 allele carriers exhibited greater bilateral MTL activity relative to noncarriers while accomplishing the same encoding task. Moreover, whereas ε4 carriers demonstrated a greater functional connectivity of ESA‐related MTL activity with the posterior cingulate and other peri‐limbic regions, reductions in overall connectivity were found across the anterior and posterior cortices.

Conclusions

These results suggest that the APOE ɛ4 allele may influence not only functional activations within the MTL, but functional connectivity of the MTLs to other regions implicated in memory encoding. Enhanced functional connectivity of the MTLs with the posterior cingulate in young adult ε4 carriers suggests that APOE may be expressed early in brain regions known to be involved in Alzheimer's disease, long before late‐onset dementia is a practical risk or consideration. These functional connectivity differences may also reflect pleiotropic effects of APOE during early development.
Challenging subtle forms of power in deliberation: A case-study on the future of Hansen's disease colonies in Brazil
Authors: Mendonça Ricardo Fabrino
Published: September 2009

This paper analyses a micro-deliberative process in order to discuss how subtle forms of power pervade discussions and are challenged in them. The study of the First National Seminar of Former Hansen's Disease Colonies, held in Rio de Janeiro (Brazil) in 2004, shows how the power to set the agenda and the power to claim credibility to one's utterances from sources other than reason may generate inequalities among participants. The analysis also reveals these forms of power are often challenged throughout communicative exchanges. Sometimes a clash of different forms of power may help in overcoming asymmetries. Based on these findings, it is suggested micro-deliberative arenas should be as heterogeneous as possible and connected to other deliberative arenas.