bluuebunny/crossref_metadata_2025 huggingface dataset:
Modified cyanate ester resins with lower dielectric loss, improved thermal stability, and flame retardancy
Authors: Zhuo Dongxian , Gu Aijuan , Liang Guozheng , Hu Jiang‐tao , Zhou Cheng , Yuan Li
Published: January 2011

Novel modified cyanate ester (CE) resins with decreased dielectric loss, improved thermal stability, and flame retardancy were developed by copolymerizing CE with hyperbranched phenyl polysiloxane (HBPPSi). HBPPSi was synthesized through the hydrolysis of phenyltrimethoxysilane, and its structure was characterized by 1H‐NMR, 29Si‐NMR, and Fourier transform infrared spectra. The effect of the incorporation of HBPPSi into CE resin on the curing behavior, chemical structure of cured networks, and typical performance of HBPPSi/CE resins were systemically evaluated. It is found that the incorporation of HBPPSi into CE network obviously not only catalyzes the curing of CE, but also changes the chemical structure of resultant networks, and thus results in significantly decreased dielectric loss, improved thermal stability, and flame retardancy as well as water absorption resistance. For example, in the case of the modified CE resin with 10 wt% HBPPSi, its limited oxygen index is about 36.0, about 1.3 times of that of neat CE resin, its char yield at 800°C increases from 31.6 to 35.4 wt%; in addition, its dielectric loss is only about 61% of that of neat CE resin at 1 kHz. All these changes of properties are discussed from the view of the structure–property relationship. The significantly improved integrated properties of CE resin provide a great potential to be used as structural and functional materials for many cutting‐edges fields. Copyright © 2011 John Wiley & Sons, Ltd.
Dye induced great enhancement of broadband reflection from polymer stabilized cholesteric liquid crystals
Authors: Li Fasheng , Wang Lei , Sun Wenping , Liu Hairi , Liu Xiaochen , Liu Youxun , Yang Huai
Published: January 2011

A series of polymer stabilized cholesteric liquid crystals (PSCLCs) films were prepared from cholesteric liquid crystal (Ch‐LC) mixtures containing different components such as non‐reactive LC monomer, polymerizable monomer, chiral dopant, dye, and photoinitiator upon polymerization. The influence of the polymerizable monomer and dye of Ch‐LC mixtures on the reflection properties was investigated. The reflection bandwidth for all the samples can be increased by photo‐polymerization, and the network upon polymerization derived from two different polymerizable monomers with both one and two functional groups is more effective than that from one polymerizable monomer for broadening the reflection band. Especially, a dye‐doped Ch‐LC film can reflect incident light with the bandwidth over the wavelength range of 550–2350 nm, which is due to a greater pitch gradient formed inside of Ch‐LC film. The gradient pitch network structure was firstly demonstrated by scanning electron microscopy (SEM) with the film prepared from high diacrylate monomer concentration and subsequently proved by using a wash‐out/refill method. The nematic liquid crystals monomers was infiltrated into the polymer network that was prefabricated by removing the low molar weight LCs from the original PSCLCs film, and SEM exhibited the existence of a pitch gradient across the film thickness. The refilled nematic liquid crystals film showed broadband reflection after polymerzition, too. Copyright © 2011 John Wiley & Sons, Ltd.
Risk of azole‐enhanced vincristine neurotoxicity in pediatric patients with hematological malignancies: Old problem – New Dilemma
Authors: Pana Zoe Dorothea , Roilides Emmanuel
Published: January 2011

One of the most well‐known drug interactions in pediatric oncology concerns the co‐administration of itraconazole, an antifungal triazole, and vincristine, an antileukemic agent, which seems to enhance the risk of neurotoxicity of the latter, mediated through the cytochrome CYP450 enzyme system. The aim of this article is to review the metabolism of these two drugs, to analyze the published cases with severe triazole‐enhanced vincristine neurotoxicity, to discuss the pathophysiological mechanisms of this adverse effect, and to contribute in understanding the differences in triazole‐vincristine interaction severity. Pediatr Blood Cancer 2011;57:30–35. © 2011 Wiley‐Liss, Inc.
Identification of chemical constituents in extracts and rat plasma from Fructus Aurantii by UPLC‐PDA‐Q‐TOF/MS
Authors: Ma Chaoyi , Gao Wenyuan , Gao Ying , Man Shuli , Huang Luqi , Liu Changxiao
Published: January 2011

Introduction – Fructus Aurantii, as a component of several compound formulae, shows many bioactivities. As is well known, the constituents of traditional Chinese medicines are very complex and multiple constituents are responsible for the therapeutic effect. However, the concrete compounds are difficult to confirm. Therefore, studies on the constituents absorbed into serum and their metabolites are necessary.

Objective – To search for the active constituents in Fructus Aurantii.

Methodology – An ultra‐performance liquid chromatography–photodiode array detector–quadrupole time‐of‐flight mass spectrometry (UPLC‐PDA‐Q‐TOF/MS) method was established to analyse the aqueous extract in Fructus Aurantii and the constituents absorbed into blood. Compound identification was made by matching the empirical molecular formula with those of the reported compounds and UV spectra, and further elucidated by lower energy CID mass spectra.

Results – Twelve flavonoidO‐glycosides were detected, and nine compounds were tentatively identified as polymethoxylated flavones. Six parent compounds were identified and four metabolites were observed in rat plasma, two of which were identified as naringenin glucuronide and hesperetin glucuronide, respectively.

Conclusion – The approach developed has proved useful in the study of the active constituents in traditional Chinese medicines. Copyright © 2011 John Wiley & Sons, Ltd.
Phytochemical fingerprinting of vegetable Brassica oleracea and Brassica napus by simultaneous identification of glucosinolates and phenolics
Authors: Velasco Pablo , Francisco Marta , Moreno Diego A. , Ferreres Federico , García‐Viguera Cristina , Cartea María Elena
Published: January 2011

Introduction – Brassica vegetables have been related to the prevention of cancer and degenerative diseases, owing to their glucosinolate and phenolic content.

Objective – Identification of glucosinolates, flavonoids and hydroxycinnamic acids in representative varieties of kale, cabbage and leaf rape.

Methodology – One local variety of each crop was evaluated in this study using a multi‐purpose chromatographic method that simultaneously separates glucosinolates and phenolics. Chromatograms were recorded at 330 nm for flavonoid glycosides and acylated derivatives and 227 nm for glucosinolates.

Results – Eight glucosinolates were identified in kale and cabbage, which exhibited the same glucosinolate profile, and 11 glucosinolates were identified in leaf rape. Furthermore, 20 flavonoids and 10 hydroxycinnamic acids were detected in kale and cabbage, while 17 flavonoids and eight hydroxycinnamic acids were found in leaf rape.

Conclusions – This study has provided a deeper and comprehensive identification of health‐promoting compounds in kale, cabbage and leaf rape, thus showing that they are a good source of glucosinolates and phenolic antioxidants. Copyright © 2011 John Wiley & Sons, Ltd.
Isolation of four high‐purity dammarane saponins from extract of Panax notoginseng by centrifugal partition chromatography coupled with evaporative light scattering detection in one operation
Authors: Wang Jing , Liu Chun‐ming , Li Li , Bai He‐long
Published: January 2011

Introduction – Centrifugal partition chromatography (CPC), as a continuous liquid–liquid partition chromatography with no solid support matrix, combined with evaporative light scattering detection (ELSD) was employed for systematic separation and purification of weak‐chromophoric saponins from a highly valued and important traditional Chinese herbal medicine, Panax notoginseng.

Objective – To separate and isolate high‐purity saponins from extract of Panax notoginseng using CPC‐ELSD with a simple and low toxicity solvent system.

Methodology – Samples were preparaed by extracting the root material with acetone, treated with n‐butanol and then freeze‐dried. CPC‐ELSD was applied in the separation and detection of notoginsenoside and ginsenosides from extract of Panax notoginseng using a solvent system composed of ethyl acetate–n‐butanol–water (1:1:2, v/v/v). The saponins were analysed and identified by their retention time with high‐performance liquid chromatography (HPLC) coupled with ELSD, as well as electrospray ionisation tandem mass spectrometry (ESI‐MSn
) in the negative and positive ion modes with the authentic standards.

Results – A total of 9.6 mg of notoginsenoside R1, 67.8 mg of ginsenoside Rg1, 2.3 mg of Re and 286.5 mg of Rb1 were purified from 487.2 mg of n‐butanol extract of P. notoginseng. The purities of obtained saponins in a single run were assessed to be over 98% by HPLC‐ELSD.

Conclusion – CPC‐ELSD was proved to be a very fast and efficient tool for separation of high‐purity dammarane saponins. Copyright © 2011 John Wiley & Sons, Ltd.
Long‐term use of zopiclone, zolpidem and zaleplon among Danish elderly and the association with sociodemographic factors and use of other drugs
Authors: Andersen Ane Birgitte Telén , Frydenberg Morten
Published: January 2011

Purpose

To estimate the degree of long‐term use of zopiclone, zolpidem and zaleplon among Danes aged 65 and older and the association with sociodemographic factors and use of other drugs.

Methods

Danish register‐based study of 5000 men and 5000 women aged 65 or older on 1 January 2004. Information on sociodemographic factors and drug redemptions were collected for 2003, with follow‐up of zopiclone, zolpidem and zaleplon redemptions in 2004. Long‐term use was defined as redemptions corresponding to a continuous daily use for more than 4 weeks (based on ½ DDD). The association between long‐term use and sociodemographics and drug use was estimated by logistic regression.

Results

Ten per cent of all men and 16% of all women had a long‐term use for minimum 4 weeks corresponding to 94% of the male and 93% of the female users. Four per cent of the men and 6% of the women had redeemed more than ½ DDD per day in 2004. Long‐term use was associated with: Being a woman, high age, widowed or divorced, high education and high gross income. Long‐term use was also associated with use of other drugs, the association with ATC group N being the strongest. Restricting the analyses to individuals who had minimum one zopiclone, zolpidem or zaleplon redemption gave similar results.

Conclusion

The results indicate that the guidance for length of use is not followed. Long‐term use of zopiclone, zolpidem and zaleplon is associated with sociodemographic factors and use of other drugs, particularly from ATC group N. Copyright © 2011 John Wiley & Sons, Ltd.
Fire retardant properties of intumescent polypropylene composites filled with calcium carbonate
Authors: Isitman Nihat Ali , Dogan Mehmet , Bayramli Erdal , Kaynak Cevdet
Published: January 2011

This study was aimed to investigate the influence of calcium carbonate (CaCO3), a widely used filler, on the fire retardancy of intumescent polypropylene composites. Two intumescent systems based on (1) mixture of ammonium polyphosphate (APP) and pentaerythritol and (2) surface‐modified APP (m‐APP) were examined. In terms of steady heat release rate, total heat evolved, and fire growth index determined by mass loss calorimetry, m‐APP performed markedly superior to APP‐pentaerythritol. The presence of CaCO3 in both intumescent formulations caused significant losses in fire retardant performance assessed by mass loss calorimetry, limiting oxygen index and UL‐94 tests. Peak rates of heat release and mass loss during combustion, and total heat evolved on combustion were increased, whereas time to ignition was decreased. Characterization of fire residues ascribed the mechanism of deterioration in fire retardancy to the formation of porous and nonexpanded crystalline calcium phosphate/CaCO3 residues during combustion rather than the amorphous protective intumescent chars formed in the absence of CaCO3. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Synthesis and properties of photosensitive poly(urethane‐acrylate) containing anil groups with application in the chemosensors area
Authors: Buruiana Emil C. , Jitaru Florentina , Hitruc Gabriela , Buruiana Tinca
Published: January 2011

Some aspects of the enol‐imine to keto‐enamine photoisomerism and fluorescent behavior of the new monomer with urethane and anil units in its structure, namely, methacryloyloxyethyl‐2‐carbamoyloxy(m‐methyl, o‐hydroxybenziliden)aniline (UAN), were studied comparatively with the corresponding copolymer poly (methacryloyloxyethyl‐2‐carbamoyloxy(m‐methyl, o‐hydroxybenziliden)aniline)‐co‐methyl methacrylate) (COP‐UAN). The structure, thermal properties, and morphology of the anil compounds were investigated by Fourier transform infrared, proton nuclear magnetic resonance, fluorescence spectroscopies, UV spectrophotometry, thermogravimetric analysis, differential scanning calorimetry, and atomic force microscopy. The photochromic behavior of salicylideneanil units was investigated by UV/laser irradiation, and an inspection of their photophysical properties suggested that such structures could function as fluorescent chemosensors for some transition metals, a fluorescence quenching in the presence of different metal cations (Fe3+, Fe2+, Cu2+, and Ni2+) being evidenced. The direct observation of an enhancement in the fluorescence emission caused of the presence of Zn2+ (solution) or Fe2+, Cu2+, and Zn2+ (thin film) would be rather suitable for the production of turn‐on fluorescent chemosensors. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Mechanical properties and deformation behaviors of acrylonitrile‐butadiene‐styrene under Izod impact test and uniaxial tension at various strain rates
Authors: Xu X.Y. , Xu X.F.
Published: January 2011

Two polybutadiene‐graft‐acrylonitrile‐styrene copolymer (PBD‐g‐SAN) impact modifiers with different rubber particle size were synthesized by seeded emulsion polymerization. Acrylonitrile‐butadiene‐styrene (ABS) blends with a constant rubber concentration of 15 wt% were prepared by blending those impact modifiers and SAN resin. The major focus was the mechanical properties and deformation mechanisms of ABS blends under Izod impact test and uniaxial tension at various strain rates from 2.564 × 10−4 S−1 upto 1.282 × 10−1 S−1. By the combination of transmission electron microscope and scanning electron microscope, it was concluded that crazes and cavitation coexisted in ABS blends. The deformation mechanisms of ABS blend containing large rubber particles was rubber particles cavitation and shear yielding in the matrix including crazes, and they do not change with the strain rate. Different from ABS blend with large rubber particles, deformation mechanism of ABS with small rubber particles under tensile condition was only involved in shear yielding in the matrix and no crazes were formed. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Processing and characterization of recycled poly(ethylene terephthalate) blends with chain extenders, thermoplastic elastomer, and/or poly(butylene adipate‐co‐terephthalate)
Authors: Srithep Yottha , Javadi Alireza , Pilla Srikanth , Turng Lih‐Sheng , Gong Shaoqin , Clemons Craig , Peng Jun
Published: January 2011

Poly(ethylene terephthalate) (PET) resin is one of the most widely used thermoplastics, especially in packaging. Because thermal and hydrolytic degradations, recycled PET (RPET) exhibits poor mechanical properties and lacks moldability. The effects of adding elastomeric modifiers, chain extenders (CE), and poly(butylene adipate‐co‐terephthalate), PBAT, as a toughener to RPET on its moldability and mechanical property were investigated. Melt blending of RPET with CE, thermoplastic elastomer (TPE), and/or PBAT was performed in a thermokinetic mixer (K‐mixer). The blended materials were then injection molded to produce tensile specimens. Various techniques were used to study the mechanical properties, rheological properties, compatibility, and crystallization behavior of the RPET blends. By melt blending with proper additives, recycled PET regained its moldability, thereby enabling the recycling of RPET. Furthermore, the addition of CE greatly enhanced the mechanical properties of RPET. While the RPET and TPE blends also showed improved mechanical properties, the improvement was less significant and the blends were often immiscible due to the difference in polarities between RPET and TPE. Finally, it was found that the mechanical properties of RPET blends depended on the prior thermal history of the material and could be improved with an extra annealing step that increased the degree of crystallinity. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Synthesis of main‐chain poly(carbazole)s via CuAAC
Authors: Chen Zheng , Dreyer Daniel R. , Wu Zong‐quan , Wiggins Kelly M. , Jiang Zhenhua , Bielawski Christopher W.
Published: January 2011

The synthesis and characterization of a novel family of main‐chain carbazole‐containing polymers using copper‐catalyzed azide‐alkyne cycloaddition chemistry is reported. The reactions were performed under mild conditions using readily available copper catalysts and ligands, which afforded polymeric products with Mws up to 18 kDa. Using a range of techniques, the polymers were found to exhibit a glass transition temperature (Tg) of 85 °C, high thermal stability (Td = 274 °C), and high photoluminescent quantum efficiency (ϕf = 0.29; λem = 448 nm), which underscore their potential for use in organic light‐emitting diodes or other emissive devices, particularly where efficient blue emission is of value. The approach described offers practical advantages over other synthetic methods used to prepare main‐chain carbazole‐containing polymers, especially with regard to the lack of need for rigorously inert conditions and the absence of byproducts generated during the polymerization reaction. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Influence of electronic effects from bridging groups on synthetic reaction and thermally activated polymerization of bisphenol‐based benzoxazines
Authors: Wang Xiaoying , Chen Feng , Gu Yi
Published: January 2011

Six bis‐benzoxazines based on bisphenols with different bridging groups, C(CH3)2, CH2, O, CO, SO2, and single bond, were synthesized in toluene. The influence of electronic effects from bridging groups on ring‐forming reaction and thermal ring‐opening polymerization were relatively discussed in detail. Their structures were characterized by high‐performance liquid chromatography, Fourier transform infrared, 1H NMR, differential scanning calorimetry, and elementary analysis. The quantum chemistry parameters of the bisphenols and bis‐benzoxazines were calculated by molecular simulation. The results indicated that the electron‐withdrawing groups inhibited the synthetic reaction by decreasing the charge density of α‐Cs of bisphenols and increasing energy barriers of the synthetic reactions. However, the electron‐withdrawing groups promoted the thermally activated polymerization, which resulted from their activation energy and curing temperature decrease by increasing the bond length and lowering the bond energy of CO on oxazine rings. Besides, because of stronger electron‐withdrawing sulfone group, there were more arylamine methylene Mannich bridge structure in the polybenzoxazine. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of poly(tert‐butyl methacrylate)‐graft‐poly(dimethylsiloxane) graft copolymers via reversible addition‐fragmentation chain transfer polymerization
Authors: Li Jiawei , Yi Lingmin , Lin Heming , Hou Ruigang
Published: January 2011

Well‐defined poly(tert‐butyl methacrylate)‐graft‐poly (dimethylsiloxane) (PtBuMA‐g‐PDMS) graft copolymers were synthesized via reversible addition‐fragmentation chain transfer (RAFT) copolymerization of methacryloyl‐terminated poly (dimethylsiloxane) (PDMS‐MA) with tert‐butyl methacrylate (tBuMA) in ethyl acetate, using 2,2′‐azobis(isobutyronitrile) (AIBN) as the initiator and 2‐cyanoprop‐2‐yl dithiobenzoate as the RAFT agent. The RAFT statistical copolymerization of PDMS‐MA with tBuMA is shown to be azeotropic and the obtained PtBuMA‐g‐PDMS graft copolymers have homogeneously distributed branches because of the similar reactivity of monomers (rtBuMA ≈ rPDMS‐MA ≈ 1). By the RAFT block copolymerization of PDMS‐MA with tBuMA, moreover, narrow molecular weight distribution (Mw/Mn < 1.3) PtBuMA‐g‐PDMS graft copolymers with gradient or blocky branch spacing were synthesized. The graft copolymers exhibit the glass transitions corresponding to the PDMS and PtBuMA phase, respectively. However, the arrangement of monomer units in copolymer chains and the length of PtBuMA moieties have important effects on the thermal behavior of PtBuMA‐g‐PDMS graft copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Narrow disperse polymers using amine functionalized dithiobenzoate RAFT agent and easy removal of thiocarbonyl end group from the resultant polymers
Authors: Jana Satyasankar , Parthiban Anbanandam , Chai Christina L.L.
Published: January 2011

A novel amine functionalized RAFT agent, 2‐cyanoprop‐2‐yl(4‐N,N‐dimethylaminophenyl) dithiobenzoate has been synthesized and used to control the polymerization of vinyl monomers. This dithiobenzoate RAFT agent, although air sensitive, controlled the polymerization of MMA and St very well in an inert atmosphere and the polymerization results obtained were marginally better than using the most popular 2‐cyanoprop‐2‐yl dithiobenzoate RAFT agent. The living nature of these polymerizations was confirmed by kinetics study and chain extension reactions to yield narrow disperse di‐block copolymers. Most importantly, use of this novel RAFT agent simplified the removal procedure of the color causing end thiocarbonyl group from the RAFT derived polymers and thereby leading to polymers with improved appearance. The removal of end group from the polymer was confirmed by 1H NMR and UV‐vis spectroscopic techniques. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Relationship of knowledge of psychosocial issues about cancer with psychic distress and adjustment among breast cancer clinic attendees in a Nigerian teaching hospital
Authors: Ohaeri Beatrice M. , Ofi Abosede B. , Campbell Oladapo B.
Published: January 2011

Objectives: The diagnosis of breast cancer prompts emotional reactions, which predispose to psychosocial problems and poor adjustment. Assessment of the psychosocial issues could help articulation of specific interventions. There is paucity of data on psychosocial issues in breast cancer from Nigeria. We assessed knowledge of psychosocial issues about breast cancer and its association with psychic distress and adjustment among women attending a Nigerian teaching hospital.

 Methods: We used a descriptive survey design to assess 63 consecutive clinic attendees (mean age: 49.9, SD: 10.5) who met the eligibility criteria. Data were obtained using the following: a 15‐item self‐report validated psychosocial needs questionnaire, General Health Questionnaire (GHQ‐12) and 10‐item adjustment scale.

 Results: Majority (63.4%) indicated they did not know much about the nature of breast cancer. The greatest area of worry was related to fear of death (81.0%). Knowledge about management of breast cancer was significantly inversely correlated with psychic distress (p<0.03). High psychic distress was significantly related to psychosocial concerns (p<0.01), and inversely correlated with adjustment (p<0.001).The most important predictor of psychic distress and adjustment was their fear about how people reacted to them.

 Conclusions: The findings support previous reports indicating that psychosocial concerns are associated with psychic distress and poor adjustment in breast cancer. Accordingly, a regular psycho‐oncology service should include counseling on improved prognosis in cancer with early patronage of modern treatments, to allay fear of death; while public health education on social stigma should address fear of negative reactions from people. Copyright © 2011 John Wiley & Sons, Ltd.
Protein disulfide isomerase isomerizes non‐native disulfide bonds in human proinsulin independent of its peptide‐binding activity
Authors: Winter Jeannette , Gleiter Stefan , Klappa Peter , Lilie Hauke
Published: January 2011

Protein disulfide isomerase (PDI) supports proinsulin folding as chaperone and isomerase. Here, we focus on how the two PDI functions influence individual steps in the complex folding process of proinsulin. We generated a PDI mutant (PDI‐aba′c) where the b′ domain was partially deleted, thus abolishing peptide binding but maintaining a PDI‐like redox potential. PDI‐aba′c catalyzes the folding of human proinsulin by increasing the rate of formation and the final yield of native proinsulin. Importantly, PDI‐aba′c isomerizes non‐native disulfide bonds in completely oxidized folding intermediates, thereby accelerating the formation of native disulfide bonds. We conclude that peptide binding to PDI is not essential for disulfide isomerization in fully oxidized proinsulin folding intermediates.
A secretory system for bacterial production of high‐profile protein targets
Authors: Kotzsch Alexander , Vernet Erik , Hammarström Martin , Berthelsen Jens , Weigelt Johan , Gräslund Susanne , Sundström Michael
Published: January 2011

Escherichia coli represents a robust, inexpensive expression host for the production of recombinant proteins. However, one major limitation is that certain protein classes do not express well in a biologically relevant form using standard expression approaches in the cytoplasm of E. coli. To improve the usefulness of the E. coli expression platform we have investigated combinations of promoters and selected N‐terminal fusion tags for the extracellular expression of human target proteins. A comparative study was conducted on 24 target proteins fused to outer membrane protein A (OmpA), outer membrane protein F (OmpF) and osmotically inducible protein Y (OsmY). Based on the results of this initial study, we carried out an extended expression screen employing the OsmY fusion and multiple constructs of a more diverse set of human proteins. Using this high‐throughput compatible system, we clearly demonstrate that secreted biomedically relevant human proteins can be efficiently retrieved and purified from the growth medium.
Crystal structure of the Nogo‐receptor‐2
Authors: Semavina Mariya , Saha Nayanendu , Kolev Momchil V. , Goldgur Yehuda , Giger Roman J. , Himanen Juha P. , Nikolov Dimitar B.
Published: January 2011

The inhibition of axon regeneration upon mechanical injury is dependent on interactions between Nogo receptors (NgRs) and their myelin‐derived ligands. NgRs are composed of a leucine‐rich repeat (LRR) region, thought to be structurally similar among the different isoforms of the receptor, and a divergent “stalk” region. It has been shown by others that the LRR and stalk regions of NgR1 and NgR2 have distinct roles in conferring binding affinity to the myelin associated glycoprotein (MAG) in vivo. Here, we show that purified recombinant full length NgR1 and NgR2 maintain significantly higher binding affinity for purified MAG as compared to the isolated LRR region of either NgR1 or NgR2. We also present the crystal structure of the LRR and part of the stalk regions of NgR2 and compare it to the previously reported NgR1 structure with respect to the distinct signaling properties of the two receptor isoforms.
Suppression correction and characteristic study in liquid chromatography/Fourier transform mass spectrometry measurements
Authors: Ma Xuepo , Hestilow Travis J. , Cui Jian , Zhang Jianqiu
Published: January 2011

Analysis of peptide profiles from liquid chromatography/Fourier transform mass spectrometry (LC/FTMS) reveals a nonlinear distortion in intensity. Investigation of the measured C13/C12 ratios comparing with theoretical ones shows that the nonlinearity can be attributed to signal suppression of low abundance peptide peaks. We find that the suppression is homogenous for different isotopes of identical peptides but non‐homogenous for different peptides. We develop an iterative correction algorithm that corrects the intensity distortions for peptides with relatively high abundance. This algorithm can be applied in a wide range of applications using LC/FTMS. We also analyze the distortion characteristics of the instrument for lower abundance peptides, which should be considered when interpreting quantification results of LC/FTMS. Copyright © 2011 John Wiley & Sons, Ltd.
Impact ionisation spectra from hypervelocity impacts using aliphatic poly(methyl methacrylate) microparticle projectiles
Authors: Burchell Mark J. , Armes Steven P.
Published: January 2011

We report impact ionisation spectra from spherical poly(methyl methacrylate) (PMMA) microparticles of 724 nm diameter impacting a rhodium target. These projectiles were coated with an ultrathin (∼11 nm) overlayer of polypyrrole, an electrically conducting organic polymer; this enabled the accumulation of sufficient surface charge to allow electrostatic acceleration up to speeds of 4 to 8 km s−1 using a high‐voltage Van de Graaff instrument. A grid above the target (held at 3.33 kV cm−1 with respect to the target) accelerated the cations that were generated during the hypervelocity impacts, and these ions then drifted to a charge detector. By measuring the collected charge vs. time and assuming only single ionisation events, time‐of‐flight mass spectra were obtained. Strong signals were observed for cationic species with ions of m/z 41, 65 and 115. There were also minor contributions from cations with masses ranging from m/z 29 to 142. The three major signals are assigned to fragment ions (C3H, C4H5O+/C5H and C6H11O) which are known to be associated with the decomposition of PMMA. These impact ionisation spectra differ significantly from those reported earlier using polystyrene (PS) microparticles. The aliphatic PMMA microparticles generate small (m/z <100) fragment ions more readily at lower speeds than the predominantly aromatic PS microparticles, where speeds of at least 10 km s−1 are typically required for substantial yields of low‐mass fragment ions. This correlates well with the well‐known greater chemical and thermal fragility of PMMA compared to PS. The PMMA microparticles should prove useful synthetic mimics for aliphatic carbonaceous micrometeorites. Copyright © 2011 John Wiley & Sons, Ltd.
A laboratory training and evaluation technique for robot assisted ex vivo kidney transplantation
Authors: Khanna Ajai , Horgan Santiago
Published: January 2011

The technique of kidney transplantation has been well established. The operation is typically performed through a lower quadrant muscle cutting incision. With advances in robotic technology, many procedures are now being performed using the robot. This article describes a simple model of ex‐vivo kidney transplantation using the robotic technique. This is a good training model and could be applied in select group of patients in the clinical setting. Copyright © 2011 John Wiley & Sons, Ltd.
Ecological modernization and environmental policy reform in Thailand: the case of food processing SMEs
Authors: Wattanapinyo Ajchara , Mol Arthur P. J.
Published: January 2011

To mitigate environmental pollution from a rapidly expanding Thai food processing industry, different options and technologies can be identified. However, actually implementing these environmental improvements within small and medium‐sized agro‐food companies requires governing efforts of a variety of actors. This paper assesses feasible paths towards the ecological modernization of small and medium‐sized agro‐food processing industries in Thailand. A so‐called quartet‐network model is applied to analyze the greening potentials for small and medium‐sized enterprises in three agro‐food sectors in Northern Thailand: fruit and vegetable processing industries, meat processing companies and fruit wine enterprises. Conclusions are drawn on how actors in the networks around these companies could contribute towards a more sustainable development of these companies. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.
Intrusion diagnosis and prediction with expert system
Authors: Liu Xuejiao , Fang Chengfang , Xiao Debao
Published: January 2011

Network diagnosis and attack prediction can help the network administrator to take timely actions to defend against well‐planned attacks that exploit a chain of vulnerabilities. One important data source for such analysis is the alerts generated by intrusion detection systems (IDS) deployed over the network. However, IDS typically generates overwhelming amount of alerts, where one cannot simply aggregate or discard. In addition, the chance of a successful exploit depends on many hidden factors such as system status and attacker power, and thus the dependencies among exploits and conditions are typically too complicated to analyze under probability framework. In this paper, we employ expert system to deal with such uncertainties and conduct certainty factor inference. We show that analysis in fuzzy system is tractable and we propose an algorithm to analyze the network status and predict the potential attacks. Finally, we give a case study to illustrate our algorithm and evaluate the effectiveness of our approach on the DARPA data sets. Copyright © 2011 John Wiley & Sons, Ltd.
Symmetric key infrastructure for authenticated key establishment between resource constrained nodes and powerful devices
Authors: Vossaert Jan , Lapon Jorn , De Decker Bart , Naessens Vincent
Published: January 2011

This paper presents a generic lightweight solution for authentication between powerful devices and resource constrained nodes. The approach is validated through the architectural design of multiple applications in different domains. The paper further discusses variants that might increase the usability of the approach in different settings. More precisely, the solution is tuned for open systems, closed systems and hierarchically structured systems. Further, two use cases are presented in which the open system and closed system approach is applied. Copyright © 2011 John Wiley & Sons, Ltd.
Could firewall rules be public – a game theoretical perspective
Authors: Liao Qi , Li Zhen , Striegel Aaron
Published: January 2011

Firewalls are among the most important components in network security. Traditionally, the rules of the firewall are kept private under the assumption that privacy of the ruleset makes attacks on the network more difficult. We posit that this assumption is no longer valid in the Internet of today due to two factors: the emergence of botnets reducing probing difficulty and second, the emergence of distributed applications where private rules increase the difficulty of troubleshooting. We argue that the enforcement of the policy is the key, not the secrecy of the policy itself. In this paper, we demonstrate through the application of game theory thatpublicfirewall rules when coupled with false information (lying) are actually better than keeping firewall rules private, especially when taken in the larger group context of the Internet. Interesting scenarios arise when honest, public firewalls are socially insured by other lying firewalls and networks adopting public firewalls become mutually beneficial to each other. The equilibrium under multiple‐network game is socially optimal because the percentage of required lying firewalls in social optimum is much smaller than the percentage in single‐network equilibrium and the chance of attacking through firewalls is further reduced to zero. Copyright © 2011 John Wiley & Sons, Ltd.
Complex software project development: agile methods adoption
Authors: Mishra Deepti , Mishra Alok
Published: January 2011

The Agile Software Development paradigm has become increasingly popular in the last few years, since it claims lower costs, better productivity, better quality and better business satisfaction. Supply chain management (SCM) is a complex software development project. Owing to its scope and uncertain, complex and unstable requirements, it is not possible to develop it with predictable software development process models. Agile methodologies are targeted toward such kinds of problems that involve change and uncertainty, and are adaptive rather than predictive. How an agile process is introduced will significantly impact the implementation success of the process change. The objective of this paper is to analyze the agile development methodologies and management approach used in developing a complex software project. This further demonstrates how to overcome risks and barriers in each development phase of such complex inventive software projects. It also provides a set of guidelines regarding how the agile methodologies can be adopted, combined and used in these kinds of complex software projects. These findings have implications for software engineers and managers developing software by agile methods. Copyright © 2011 John Wiley & Sons, Ltd.
Decomposition tool for event‐B
Authors: Silva Renato , Pascal Carine , Hoang Thai Son , Butler Michael
Published: January 2011

Two methods have been identified for Event‐B model decomposition: shared variable and shared event. The purpose of this paper is to introduce the two approaches and the respective tool support in the Rodin platform. Besides alleviating the complexity for large systems and respective proofs, decomposition allows team development in parallel over the same Event‐B project which is very attractive in the industrial environment. Copyright © 2011 John Wiley & Sons, Ltd.
A retrospective on CZT
Authors: Malik Petra
Published: January 2011

Community Z Tools (CZT) is an open‐source Java framework for building formal methods tools for the specification language Z and extensions of Z. This paper gives an overview of CZT: its history, architecture, and development process. Extensibility is core to CZT and the main aims of this paper are to encourage and enable formal methods tool developers to utilize, extend, and contribute to CZT. The paper is also of value to people interested in open‐source or formal methods software in general since many of the techniques and practices described are not specific to CZT and could be applied to other frameworks. Copyright © 2011 John Wiley & Sons, Ltd.
Determination of Hydrogen Solubility in Fe–Mn–C Melts
Authors: Lob Alexander , Senk Dieter , Hallstedt Bengt
Published: January 2011

High manganese steels are supposed to be sensitive to hydrogen embrittlement. This can be explained by increased hydrogen solubility in comparison to unalloyed steels. To minimise hydrogen pick up during melting operations, it is necessary to know accurately the hydrogen solubility as function of hydrogen partial pressure, temperature and Mn content. In this work in situ measurements of hydrogen content at 12, 18 and 23 wt.% Mn (and 0.6 wt.% C) using the Hydris® system are compared to pin‐tube measurements. Below about 7 ppm [H] both methods gave the same results and above 7 ppm [H] the in situ measurement showed slightly higher hydrogen contents because some hydrogen is lost during quenching with the pin‐tube method. The measured solubilities were compared with thermodynamic calculations. Using dilute solution theory with data developed for alloyed Fe‐based melts with up to 10 wt.% Mn gives reasonable results except that the hydrogen solubility is slighltly underestimated for the presently investigated Mn contents. This could be compensated by using an interaction parameter of e = –0.004 instead of e = –0.0012. A Calphad type extrapolation from the binary Fe–H, Mn–H and Fe–Mn systems gave results very close to the experimental ones. This work is a contribution from the collaborative research centre SFB 761 “Steel – ab initio”.
Characterization of Nano‐Sized Precipitates in a Mn‐Based Lean Maraging Steel by Atom Probe Tomography
Authors: Millán J. , Ponge D. , Raabe D. , Choi P. , Dmitrieva O.
Published: January 2011

We present atom probe tomography results of a precipitation‐hardened Mn‐based maraging steel (9 Mn, 1.9 Ni, 0.6 Mo, 1.1 Ti, 0.33 Al; in at.%). The alloy is characterized by the surprising effect that both, strength and total elongation increase upon aging. The material reveals a high ultimate tensile strength (UTS) up to 1 GPa and good ductility (total elongation (TE) of up to 15% in a tensile test) depending on aging conditions. We map the evolution of the precipitates after 450 °C aging treatment using atom probe tomography in terms of chemical composition and size distribution.
Abnormalities of the upper extremities on fetal magnetic resonance imaging
Authors: Nemec S. F. , Kasprian G. , Brugger P. C. , Bettelheim D. , Amann G. , Nemec U. , Rotmensch S. , Graham J. M. , Rimoin D. L. , Lachman R. S. , Prayer D.
Published: January 2011

Objective

In view of the increasing use of fetal magnetic resonance imaging (MRI) as an adjunct to prenatal ultrasonography, we sought to demonstrate the visualization of upper extremity abnormalities and associated defects on MRI, with regard to fetal outcomes and compared with ultrasound imaging.

Methods

This retrospective study included 29 fetuses with upper extremity abnormalities visualized with fetal MRI following suspicious ultrasound findings and confirmed by postnatal assessment or autopsy. On a 1.5‐Tesla unit, dedicated sequences were applied to image the extremities. Central nervous system (CNS) and extra‐CNS anomalies were assessed to define extremity abnormalities as isolated or as complex, with associated defects. Fetal outcome was identified from medical records. MRI and ultrasound findings, when available, were compared.

Results

Isolated upper extremity abnormalities were found in three (10.3%) fetuses. In 26 (89.7%) fetuses complex abnormalities, including postural extremity disorders (21/26) and structural extremity abnormalities (15/26), were demonstrated. Associated defects involved: face (15/26); musculoskeletal system (14/26); thorax and cardio/pulmonary system (12/26); lower extremities (12/26); brain and skull (10/26); and abdomen (8/26). Of the 29 cases, 18 (62.1%) pregnancies were delivered and 11 (37.9%) were terminated. MRI and US findings were compared in 27/29 cases: the diagnosis was concordant in 14 (51.9%) of these cases, and additional findings were made on MRI in 13/27 (48.1%) cases.

Conclusions

Visualization of upper extremity abnormalities on fetal MRI enables differentiation between isolated defects and complex ones, which may be related to poor fetal prognosis. MRI generally confirms the ultrasound diagnosis, and may provide additional findings in certain cases. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
The role of law in adapting to climate change
Authors: McDonald Jan
Published: January 2011

Legal institutions and instruments will play an important role in climate change adaptation, along with technological, managerial, and behavioral strategies. Law can facilitate adaptation, using regulation to reduce exposure or sensitivity to climate hazards, establishing the legal architecture for new market mechanisms, and funding arrangements for adaptation costs and liability for climate impacts. It can also ensure the accountability of adaptation decision making and addressing some of the social justice dimensions of adaptation. Yet there are also characteristics of legal institutions, processes, and principles that may impede adaptation, including by creating compensable property rights that hinder new regulation. There are several characteristics of climate change and associated impacts that will make law‐making for adaptation uniquely challenging. These include high levels of cascading uncertainty, irreversibility, the context‐specificity of impacts, the long delay between emissions and impacts, and the interaction between climate change impacts and other environmental, social, and economic stressors. Laws dealing with substantive climate impacts may be appropriate and necessary in some cases, but the broader challenge for law‐makers is to make legal processes and instruments more adaptive and responsive to change itself.WIREs Clim Change2011 2 283–295 DOI: 10.1002/wcc.96

This article is categorized under:

Vulnerability and Adaptation to Climate Change > Institutions for Adaptation
Joint optimization of power allocation and relay location for regenerative relaying with multi‐antenna reception at destination
Authors: Zhang Xiao Juan , Gong Yi
Published: January 2011

We consider joint power allocation (PA) and relay positioning in a dual‐hop regenerative relay system with multiple antennas equipped at the destination. With a fixed relay location, an adaptive PA strategy at the source and relay under a sum power constraint that minimizes the system outage probability is presented. With a fixed PA strategy, the optimal relay location is derived. We then propose to jointly optimize PA and relay location. It is shown that employing more destination antennas and/or choosing an appropriate relay location can significantly save the power needed at the relay. Numerical results are presented to demonstrate the performance of the proposed PA and relay positioning algorithms. Copyright © 2011 John Wiley & Sons, Ltd.
A study on one‐dimensionalk‐coverage problem in wireless sensor networks
Authors: Li Lei , Zhang Baoxian , Zheng Jun
Published: January 2011

In this paper, we study the one‐dimensional coverage problem in a wireless sensor network (WSN) and consider a network deployed along a one‐dimensional line according to a Poisson distribution. We analyze three important parameters that are related to the problem, i.e.,expected k‐coverage proportion, full k‐coverage probability, and partial k‐coverage probability, and derive mathematical models that describe the relationships between the node density in the network and these parameters. The purpose is to calculate or estimate the node density required for achieving a given coverage probability, which is useful in the deployment of a one‐dimensional network for many applications. We first analyze the expectedk‐coverage proportion, then analyze the fullk‐coverage probability fork = 1 and the lower bound to the fullk‐coverage probability fork > 1, and finally analyze the partialk‐coverage probability fork = 1 and give a brief discussion of the partialk‐coverage probability fork > 1. The mathematical models are validated through simulation. Copyright © 2011 John Wiley & Sons, Ltd.