bluuebunny/crossref_metadata_2025 huggingface dataset:
Aid, debt and fiscal policies in Senegal
Authors: Ouattara Bazoumana
Published: March 2006

This paper uses the fiscal response framework to study the effects of aid flows on key fiscal aggregates in Senegal, over the period of 1970–2000. Attention is given to the interplay between aid and debt. The paper contributes to the empirics of fiscal response modelling by deriving the standard errors and p values associated with the different mechanisms of the structural and reduced form equations. The main findings in this paper are: (i) relatively large shares of government resources are used to finance debt servicing; (ii) the impact of aid flows on domestic expenditure is statistically insignificant and (iii) debt servicing has a significant negative effect on domestic expenditure. The main policy implication of this study is that debt reduction could be a more effective policy tool than additional aid (loans) in financing pro‐poverty expenditure as well as public investment. Copyright © 2006 John Wiley & Sons, Ltd.
Incidentally detected lesions on contrast‐enhanced MR imaging in candidates for breast‐conserving therapy: Correlation between MR findings and histological diagnosis
Authors: Yabuuchi Hidetake , Kuroiwa Toshiro , Kusumoto Chie , Fukuya Tatsuro , Ohno Shinji , Hachitanda Yoichi
Published: March 2006

Purpose

To investigate the correlation between MR findings and the histological diagnosis of incidentally detected lesions in candidates for breast‐conserving therapy.

Materials and Methods

MR images of 299 patients with breast cancer were reviewed. Incidentally detected lesions were noted in 59 of 299 (20%) patients, and a histological diagnosis was obtained in 48 of 59 (81%) patients. There were 25 benign and 23 malignant lesions. The number, size, location, morphologic character, and kinetic curve assessment of the MR findings were analyzed. Statistical analyses were performed to determine whether any differences could be observed between benign and malignant lesions.

Results

Lesions of over 10 mm tended to be malignant (11/16; 69%), whereas those equal or less than 5 mm tended to be benign (12/17; 71%; P < 0.05). Lesions in the same quadrant as the main lesion tended to be malignant (20/27.5; 73%), whereas those in a different quadrant tended to be benign (17.5/20.5; 85%; P < 0.001). Lesions with early peak of enhancement tended to be malignant (20/25; 80%), whereas those with persistent enhancement tended to be benign (20/23; 87%; P < 0.001).

Conclusion

Incidentally detected lesions that are found in a different quadrant from the main lesion, are smaller than 10 mm in diameter, and show persistent enhancement on MR imaging suggest benign lesions. Therefore, patients with such lesions should avoid unnecessary surgical procedures unless lesions are proved to be malignant by cytology or biopsy. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
MRI features of pediatric cerebral paragonimiasis in the active stage
Authors: Zhang Jin Song , Huan Yi , Sun Li Jun , Zhang Guang Yun , Ge Ya Li , Zhao Hai Tao
Published: March 2006

We retrospectively reviewed the MR images of the brains of six children (age = 5–13 years) who had cerebral paragonimiasis in the early active stage. Diagnosis was based on a positive antibody test enzyme‐linked immunosorbent assay (ELISA) for paragonimiasis in serum. The most common finding (in five patients) was irregular hemorrhage of various degrees. Moreover, in three cases some multiple irregular lesions with surrounding edema appeared to be conglomerated and aggregated. The rare appearance (in one patient) was a “tunnel sign,” which showed the migrating track of the adult worm. In one patient with abscess and minimal hemorrhage, diffusion‐weighted imaging (DWI) showed a heterogeneous high signal of lesions. Other findings included slight (one patient) or marked (one patient) irregular contrast enhancement, and large edematous areas surrounding small centers of hemorrhage (two patients). MR findings of conglomerated lesions with hemorrhage or tunnel sign may help to establish the diagnosis of active‐stage cerebral paragonimiasis. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Composite right/left‐handed extended equivalent circuit (CRLH‐EEC) FDTD: stability and dispersion analysis with examples
Authors: Rennings A. , Otto S. , Caloz C. , Lauer A. , Bilgic W. , Waldow P.
Published: March 2006

A composite right/left‐handed (CRLH) extended equivalent circuit (EEC) FDTD method with a stability criterion based on a Liapunov discrete energy function is presented and applied to investigate several transient and refractive phenomena occurring at the interface between a CRLH metamaterial (MTM) and a purely right‐handed (PRH) structure. This formulation consists in an extension of the equivalent circuit (EC) Yee scheme including a left‐handed (LH) series capacitance and shunt inductance in addition to the canonical right‐handed (RH) series inductance and shunt capacitance, so as to model general CRLH transmission line (TL) MTMs. This CRLH‐EEC FDTD scheme is shown to represent a convenient numerical scheme, with remarkable formulation compactness and high computational efficiency, for the analysis of any type of MTM structure. Moreover, this scheme, coupled with a Y‐matrix representation of the EEC Yee cell, is shown to rigorously restore the dispersion/attenuation relation of CRLH MTMs. Transient solutions for the propagation of a modulated Gaussian pulse through a PRH–CRLH interface highlights interesting effects such as space‐domain compression, infinite phase velocity modulation and the well‐known backward wave effect. Frequency‐domain analysis of the fields radiated by dipoles through the Veselago–Pendry lens shows how focusing is affected both qualitatively and quantitatively by the orientation of the dipoles. Copyright © 2006 John Wiley & Sons, Ltd.
Efficient full‐wave analysis method of leaky‐wave modes in periodically loaded dielectric waveguides with application to backward‐to‐forward frequency‐scannable antennas and metamaterials
Authors: Luis Gómez‐Tornero José , Pascual García Juan , Álvarez‐Melcón Alejandro
Published: March 2006

This work presents a novel and efficient full‐wave method specifically conceived for the modal analysis of periodic planar metallizations printed on the open side of a dielectric rectangular waveguide. This particular type of structures can be used to conceive interesting backward‐to‐forward frequency‐scanning periodic leaky‐wave antennas, including leaky‐wave antennas based on the composite right–left‐handed transmission line concept (metamaterial). For the analysis, the spectral‐domain Green's functions are obtained by expanding the electromagnetic fields as a double summation of Floquet and parallel‐plate modes. An original and simple coupled equivalent circuit is used to deal with the multilayered stratification arrangement and the top radiation boundary. The method of moments (MoM) is applied to solve the corresponding EFIE/MFIE, and an original iterative technique is used to search for the complex leaky‐wave mode zeros of the determinant of the MoM matrix. All the expressions are in closed form, while keeping its full‐wave nature. The convergence and the accuracy of the method are both studied. Once the backward leaky‐waves are found, some interesting phenomena are examined, such as backward‐to‐forward beam scanning, appearance of bandgaps, mode coupling, multi‐space‐harmonic radiation, and antenna aperture illumination control. By studying a practical antenna and by comparing with previously published methods, it is shown the importance of a full‐wave analysis tool that can take into account all the aforementioned effects. Copyright © 2006 John Wiley & Sons, Ltd.
Enhancing disease resistance in harvested mango (Mangifera indica L. cv. ‘Matisu’) fruit by salicylic acid
Authors: Zeng Kaifang , Cao Jiankang , Jiang Weibo
Published: March 2006

To learn how salicylic acid (SA) may affect disease resistance in mango, mango fruit (Mangifera indica L. cv. ‘Matisu’) were treated with 1 mmol L−1 SA solution under vacuum infiltration for 2 min at a low pressure (−80 kPa) and for an additional 10 min at air pressure. The fruit were inoculated with anthracnose (Colletotichum gloeosporioides Penz.) spore suspension (1 × 104 CFU mL−1) and incubated at 13 °C, 85–95% RH. Disease incidence and lesion diameter in/on the SA‐treated fruit were 37.5% and 20.9% lower than that in/on control fruit on the 4th day of incubation. The study further showed that activities of defensive enzymes in the fruit were significantly enhanced by SA treatment. The activity of phenylalanine ammonia‐lyase (PAL) and β‐1,3‐glucanase in the SA‐treated fruit was over 6‐ or 0.9‐fold higher than that in control fruit on the 4th day after the fruit being treated with SA, respectively. Level of hydrogen peroxide (H2O2) or superoxide radicals (O2−) generation rate in SA‐treated fruit was 22.3% or 79.4% higher than that in controls on the 8th day after the fruit being treated with SA, respectively. These results suggested that PAL and β‐1,3‐glucanase, as well as H2O2 or O2−, may be involved in the enhancement of disease resistance in mango fruit. Copyright © 2006 Society of Chemical Industry
Modification of the properties of milk protein films by gamma radiation and polysaccharide addition
Authors: Cieśla Krystyna , Salmieri Stephane , Lacroix Monique
Published: March 2006

This study has demonstrated that gamma radiation induced an improvement of barrier properties and tensile strength of films containing calcium caseinate, whey protein isolate and glycerol (1:1:1) through creation of a crosslinked β‐structure. Up to 32 kGy the effect was accompanied by an increase in rigidity and was larger with increasing radiation dose. The irradiation of protein solutions also caused improvement of puncture strength of films prepared with potato starch, soluble potato starch or sodium alginate addition (at a level of 50 g kg−1 of total proteins). Addition of potato starch did not influence mechanical properties of films but significantly improved barrier properties. Addition of sodium alginate resulted in improvement of both puncture strength and barrier properties. Addition of sodium alginate to irradiated protein solution resulted in films revealing the greatest improvement in properties. Gels prepared using irradiated protein solutions mixed with calcium salt were stronger than gels prepared using non‐irradiated solutions owing to the preferred binding of calcium ions to the crosslinked protein network. Presence of sodium alginate and potato starch weakened the interaction of proteins with calcium ions owing to entrapment of proteins in the polysaccharide network, while addition of soluble potato starch promoted these interactions. Copyright © 2006 Society of Chemical Industry
Inhibitory effect of propolis extract on the growth of Listeria monocytogenes and the mutagenicity of 4‐nitroquinoline‐N‐oxide
Authors: Yang Hsin‐Yi , Chang Cheng‐Ming , Chen Yue‐Wen , Chou Cheng‐Chun
Published: March 2006

Propolis originates from a resinous substance collected by honeybees from the buds and leaves of trees and plants, which is then mixed with pollen as well as enzymes secreted by the bees. In the present study, the susceptibility of Listeria monocytogenes to the ethanol extract of propolis (EEP) as influenced by EEP concentration, incubation temperature, pH, and cell age was investigated. In addition, the antimutagenic action of EEP against 4‐nitroquinoline‐N‐oxide (4‐NQO) was also examined. Results revealed that EEP at a dosage of 7.5 µg mL−1 or higher exerted a bactericidal effect on L. monocytogenes. L. monocytogenes was most susceptible to EEP at 37 °C followed by 25 and 4 °C. At acid pH values, cells of the test organism were more sensitive to EEP than at neutral pH, while most resistant at alkaline pH values. Cell age was also found to affect the susceptibility of L. monocytogenes to EEP. Cells in the mid‐exponential phase showed the highest susceptibility, followed by cells in the late‐exponential phase and stationary phase. EEP caused cell leakage of the test organism. A marked increase in the absorbance at 260 nm, UV‐absorbing material in the supernatant of cell suspension, and irregularly shaped materials around the cell surface were noted after cells of L. monocytogenes were exposed to EEP. Furthermore, EEP at a dosage of 7.5–60.0 µg per plate was found to suppress 4‐NQO‐induced mutation by 17.6–88.8%. Copyright © 2006 Society of Chemical Industry
Effect of irrigation and lactic acid bacteria inoculants on the phenolic fraction, fermentation and sensory characteristics of olive (Olea europaea L. cv. Ascolana tenera) fruits
Authors: Marsilio Vincenzo , d'Andria Riccardo , Lanza Barbara , Russi Francesca , Iannucci Emilia , Lavini Antonella , Morelli Giovanni
Published: March 2006

Plant productivity, phenolic profile and natural fermentation, with and without lactic acid bacteria inoculants, were investigated in olive fruit of Ascolana tenera growing under different irrigation regimes. A rainfed control and two treatments receiving a water depth equivalent to 33 and 66% of the estimated crop evapotranspiration (ETc) from the pit hardening stage and a treatment with 66% of ETc during the entire season (25 May‐4 October), were tested. Olive vigour increased with irrigation, which also induced a fresh yield enhancement, mainly due to the increase in fruit size. The differences between treatments were less evident for fruit number per tree and pulp/stone ratio. The phenolic content increased in water deficit‐stressed olives and differences were detected in the concentrations of individual phenolic compounds. Olive oil content and fatty acids composition appeared scarcely affected by irrigation. Values of pH, acidity, sugars, phenolic composition and microbial population were monitored during olive fermentation. Extracts of freshly harvested olive fruits exhibited significantly higher phenolic content than extracts of processed olives. The interaction of irrigation and fermentation appeared to have a significant effect on the chemical and sensory characteristics of the end product. The bitter taste of olive fruit was positively correlated with the level of total phenolics, but negatively correlated with the overall acceptability for direct consumption. The fermentation process was accelerated in the presence of lactic acid bacteria inoculants, indicating the potential use of these microorganisms as quality control markers in table olives during processing. Copyright © 2006 Society of Chemical Industry
Effect of duration of the Montanera diet on the hydrocarbon fraction of intramuscular lipids from Iberian dry‐cured ham; characterization by gas chromatography
Authors: Petrón María J , Muriel Elena , Tejeda Juan F , Ventanas Jesús , Antequera Teresa
Published: March 2006

The characterization and differentiation of Iberian hams was studied as a function of the diet received by animals during the fattening period using a method based on hydrocarbon analysis. Thirty‐one hams were divided into three groups according to fattening diet (1, ‘Concentrate Feed’, fed on an intensive system with concentrates; 2, ‘Short Montanera’, fed on an extensive system with acorns and pasture for 50 days; and 3, ‘Long Montanera’, fed on an extensive system for 75 days). Saturated hydrocarbons in the n‐C14 to n‐C32 range and a large number of branched hydrocarbons were identified in the intramuscular fat of the three groups studied. The diet of the pigs during the fattening period did not affect the n‐alkane and n‐alkene content. The analysis of branched hydrocarbons revealed some significant differences relative to the type of diet. The ‘Concentrate Feed’ group had different concentrations of 2‐butyl‐1,1,3‐trimethylcyclohexane (P < 0.01), 3‐octadecene (P < 0.001), branched hydrocarbon 4 (P < 0.01) and neophytadiene (P < 0.001) than the ‘Montanera’ group. Copyright © 2006 Society of Chemical Industry
A cotton‐specific gene, stearoyl‐ACP desaturase, used as a reference for qualitative and real‐time quantitative polymerase chain reaction detection of genetically modified organisms
Authors: Xu Wen‐Tao , Huang Kun‐Lun , Wang Ying , Zhang Hong‐Xing , Luo Yun‐Bo
Published: March 2006

Biotechnology has permitted the modification of agricultural materials in a very precise way to improve productivity and yields. Polymerase chain reaction (PCR)‐based methods have been the first choice of most analytical laboratories for routine use in the detection of genetically modified organisms (GMO) and their derived products. These methods rely on the amplification of transgenic sequences and quantification of the transgenic DNA by comparison with an amplified reference gene. This paper describes the specific primers and probe for the cotton stearoyl‐ACP desaturase (sad1) gene, and PCR cycling conditions suitable for the use of this sequence, which acts as an endogenous reference gene in both qualitative and quantitative PCR assays. The two methods were tested with 18 cotton varieties and identical amplification products were obtained with all of them. No amplification products were detected when DNA samples from other species, including soybean, rapeseed, tobacco, maize, tomato, potato, cucumber, pea, red pepper, sunflower, sesame, rice, peach, banana, apple, pumpkin, barley and carrot, were used as templates, which demonstrates that this system is specific for cotton. In real‐time quantitative PCR analysis, the detection limit was as low as 6 pg of DNA, which indicates that this method is suitable for application to processed food samples that contain very low copies of target DNA. Southern blot analysis confirmed that the sad1 gene was a single copy in the tested cotton varieties. Copyright © 2006 Society of Chemical Industry
Effect of thermal processing on genistein, daidzein and glycitein content in soymilk
Authors: Huang Huihua , Liang Hanhua , Kwok Kin‐Chor
Published: March 2006

Soymilk was subjected to various heat treatments at 95, 121 and 140 °C for various lengths of time. The contents of the aglycones of isoflavone (daidzein, glycitein and genistein) of the soymilk were determined using C18 reversed‐phase high‐performance liquid chromatography. Genistein showed greater stability to heat treatment than daidzein and glycitein. Both the daidzein and glycitein contents decreased rapidly during the early stage of heating, but on continued heating the rates of decrease were much slower. Heating may cause an increase or decrease in the genistein content of soymilk depending on the temperature and time used. Upon heating at 95 and 121 °C, there was an increase in the genistein content in the early stage of heating, possibly due the conversion of genistin to genistein. Heating at 140 °C for more than 15 s and prolonged heating at 95 and 121 °C, however, caused a slow decline in the genistein content. Copyright © 2006 Society of Chemical Industry
Polycondensation of L‐Lysine Diketopiperazine with Tartaric Acid ‐ Evidence on the Formation of Cyclic Oligomers
Authors: Majó Maria Antònia , Bou Jordi J. , Herranz Concepción , Muñoz‐Guerra Sebastián
Published: March 2006

Summary: Reaction of active esters of O‐protected D‐and L‐tartaric acid with L‐lysine 2,5‐diketopiperazine afforded optically active low molecular weight compounds with Tg ≈ 130 °C. 13C NMR results indicated that the condensation product consisted of cyclic oligomers made from 1 to 6 repeating units. Mass spectrometric analysis by MALDI‐TOF ascertained such interpretation and suggested a revision of previous work reporting on polymerization of 2,5‐diketopiperazines.

MALDI‐TOF profile of cKT‐LL.

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MALDI‐TOF profile of cKT‐LL.
Towards Powering Nanometer‐Scale Devices with Molecular Motors: Single Molecule Engines
Authors: Butt Hans‐Jürgen
Published: March 2006

Summary: Future nanodevices such as levers, valves, pumps, and other functional parts will require molecular motors to generate mechanical work. Electrochemically switchable single polymer chains are possible candidates for such motors. The proof of principle that such a single macromolecular motor can work has been achieved using poly(ferrocenyldimethylsilane) (PFS). PFS can reversibly be oxidized and reduced by an external potential. This leads to changes in its mechanical properties, which can be used to drive a cyclic molecular engine. Such a system is compatible with a high density array of individually addressable molecular motors, e.g. by interfacing with electrodes smaller than the diffraction limit of light.

Cycle of the molecular motor consisting of a polymer chain between a surface and the end of an AFM cantilever.

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Cycle of the molecular motor consisting of a polymer chain between a surface and the end of an AFM cantilever.
Web‐Forming System Design Using CFD Modelling for Complex 3D Nonwoven Shell Structures
Authors: Wang Xiao Yan , Gong Rong Hua , Dong Zhe , Porat Isaac
Published: March 2006

Summary: CFD modelling has been used to study the unique problem of airflow containing fibres around 3D porous media in nonwoven web forming systems. The related gas‐solid two‐phase flows were simulated using a commercial CFD package, FLUENT. Simulation results revealed that the uniformity of air velocities and fibre concentration around the moulds, particularly for complex‐shaped moulds, could be improved significantly by means of employing vertically oriented web forming system and moulds with controlled porosity. Experimental results indicated that the distribution of the area densities of the 3D nonwovens produced using polypropylene/polyester bi‐component fibre followed the same patterns of the airflow and fibre distributions simulated using the CFD model. The CFD model is a valuable tool for optimising the web forming systems and improving the uniformity of the 3D nonwovens.

Area density distribution of the 3D products produced using the vertical system.

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Area density distribution of the 3D products produced using the vertical system.
Shear Enhanced Fiber Orientation and Adhesion in PP/Glass Fiber Composites
Authors: Guo Min , Yang Hong , Tan Hong , Wang Cong , Zhang Qin , Du Rongni , Fu Qiang
Published: March 2006

Summary: In order to achieve better mechanical properties, most work on polymer/fiber composites has been focused on the importance of the chemistry used to modify the surface of the fibers and improving the adhesion between the fiber and the matrix using coupling agents. Our purpose in this study was to determine the effect of shear on the fiber orientation and interfacial adhesion in poly(propylene)/glass fiber composites via dynamic packing injection molding (DPIM), in which the melt is first injected into the mold and then forced to move repeatedly in a chamber by two pistons that move reversibly with the same frequency as the solidification progressively occurs from the mold wall to the molding core part. SEM, TGA, FT‐IR, AFM and mechanical testing were used to characterize the samples obtained. The majority of fibers are aligned parallel to the flow direction along the sample thickness, even at the core, in contrast to the products obtained via conventional injection molding where the orientation of fibers is observed only at the skin. More importantly, we found that shear could enhance not only the fiber orientation, but also the interfacial adhesion between the fibers and the matrix, particularly for samples with higher fiber contents, resulting in an obvious increase in tensile strength and the onset degradation temperature. A possible transcrystallization was evidenced by AFM investigations of the dynamic packing injection molded samples, which is worth further study.

SEM micrographs representing the glass fiber after PP in the composites was extracted (GF30, dynamic sample).

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SEM micrographs representing the glass fiber after PP in the composites was extracted (GF30, dynamic sample).
Enhancement of Epoxy Resin/Copper Heterojunction by Introduction of Sulfur‐Containing Polymers
Authors: Hirano Hiroshi , Okada Takuto , Nakamura Yoshinobu , Kadota Joji , Watase Seiji , Hasegawa Kiichi
Published: March 2006

Summary: Epoxy resins are widely used in electronics and electric industries because of their superior properties. In recent years, excellent bonding properties for metals (e.g., copper, gold, aluminium, silver, etc.), to which it is hard to adhere, have become desirable for epoxy resins in the electric and electronics industrial fields. However, epoxy resins have only poor bonding strength to the metals. In order to increase the heterojunction strength between epoxy resins and copper, the introduction of sulfur, providing strong interactions with metals, was investigated. TDP polyester and MPS polythioesters containing sulfur moieties were employed as the sulfur‐containing modifiers for the epoxy resin. Epoxy resins containing a modifier (5–20 phr) and a curing agent were cured between copper plates at 120 °C for 2 h and at 170 °C for 2 h. The effect of the added modifiers was evaluated by the lap‐shear testing method. It could be demonstrated that MPS polythioesters have a beneficial effect on the enhancement of the epoxy resin/copper heterojunction. The most effective example was the addition of 20 phr of the MPS_7 polythioester, which increased the lap shear strength from 5.7 to 17 MPa.

Improvement of lap shear strengths of adhesive copper joints by sulfur‐containing modifiers.

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Improvement of lap shear strengths of adhesive copper joints by sulfur‐containing modifiers.
Correlating Polymer Parameters to the Entire Molecular Weight Distribution: Application to the Melt Index
Authors: Nele Márcio , Latado Andréa , Pinto José Carlos
Published: March 2006

Summary: A method that takes into account the entire molecular weight distribution (MWD) for the prediction of polymer point properties and/or indexes is presented. The method is based on the convolution of the polymer mass molecular weight distribution and an empirical kernel function. Thus, the problem of relating the polymers properties to the MWD is reduced to the estimation of this empirical function. The proposed methodology is able to successfully predict melt indexes (MI) of a set of poly(propylene) samples.

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A Novel Intumescent Flame‐Retardant Polyethylene System
Authors: Xie Fei , Wang Yu‐Zhong , Yang Bing , Liu Ya
Published: March 2006

Summary: A novel carbonization agent was synthesized and characterized. The flame retardancy and thermal behavior of a new IFR system with and without metal chelates for LDPE were investigated by LOI, UL‐94 test, and TGA. Metal chelates can remarkably improve the flame retardant performance of intumescent systems according to the tested results of LOI values and UL‐94 ratings because they can act both as inhibitors of radicals and as promoters of carbonization. The TG curves show that the amounts of residue of IFR‐PE/metal chelate systems increase compared to those of PE and IFR‐PE at temperatures ranging from 400 to 650 °C. The IFR‐PE/metal chelate system can obviously reduce the amounts of decomposing products at higher temperatures and promotes the formation of carbonaceous charred layers. A LOI value of 29.8 and UL‐94 V‐0 rating could be achieved when the synthesized carbonization agent, APP, MP, and CoOSA were added into LDPE.

TG curves of PE, IFR‐PE, and IFR‐PE/metal chelate systems.

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TG curves of PE, IFR‐PE, and IFR‐PE/metal chelate systems.
Simultaneous Preparation of PI/POSS Semi‐IPN Nanocomposites
Authors: Chen Wen‐Yi , Ho Ko Shan , Hsieh Tar‐Hwa , Chang Feng‐Chih , Wang Yen‐Zen
Published: March 2006

Summary: This investigation presents a simultaneous and convenient approach to produce a high‐performance polyimide with a low dielectric constant by introducing the octa‐acrylated polyhedral oligomeric silsesquioxane (methacrylated‐POSS) into a polyimide matrix to form polyimide semi‐interpenetrating polymer network (semi‐IPN) nanocomposites. The differential scanning calorimetry (DSC) and Fourier‐transform infrared (FT‐IR) results indicate that the self‐curing of methacrylated‐POSS and the imidization of polyamic acid (PAA) occurs simultaneously. The morphology of a semi‐IPN structure of polyimide/POSS‐PI/POSS nanocomposites with POSS nanoparticles embedded inside the matrix is elucidated. The POSS particles are uniform and are aggregated to a size of approximately 50–60 nm inside the polyimide matrix. The interconnected POSS particles are observed at high POSS content. The structure is highly cross‐linked, so the PI/POSS nanocomposites have an enhanced glass transition temperature. The high porosity of the PI/POSS nanocomposites markedly reduces the dielectric constant of PI because of the nanometer‐scale porous structure of POSS.

FT‐IR spectra of the various compounds of A) methacrylate‐POSS before curing, B) methacrylate‐POSS after curing, C) PAA containing 15 wt.‐% POSS, and D) PI/POSS containing 15 wt.‐% POSS.

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FT‐IR spectra of the various compounds of A) methacrylate‐POSS before curing, B) methacrylate‐POSS after curing, C) PAA containing 15 wt.‐% POSS, and D) PI/POSS containing 15 wt.‐% POSS.
A Simple Method to Fabricate a Conductive Polymer Micropattern on an Organic Polymer Substrate
Authors: Yang Peng , Xie Jingyi , Yang Wantai
Published: March 2006

Summary: Under UV irradiation plus a photomask, a hydrophilic/hydrophobic hybrid polymer surface is created by sandwiching an ammonium persulfate solution between two polymer films. It is demonstrated that an effective conductive PANI micropattern can be fabricated on such a wettability patterned surface. For PET, a stable negative micropattern could be formed directly by the selective deposition of PANI onto the hydrophobic region. Alternatively, for PP or PI, direct deposition of PANI is non‐selective, however, the PANI layer remains preferentially on the hydrophilic region by peeling off the PANI layer on the hydrophobic region to form a positive micropattern.

Schematic illustration of the procedure used for the formation of a conducting polymer (PANI) micropattern on a wettability patterned polymer substrate.

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Schematic illustration of the procedure used for the formation of a conducting polymer (PANI) micropattern on a wettability patterned polymer substrate.
Preferential Partition of Nanowires in Thin Films of Immiscible Polymer Blends
Authors: Wu Kuen‐Hua , Lu Shih‐Yuan
Published: March 2006

Summary: The preferential partition of silver nanowires in thin films of polystyrene/poly(vinyl pyrrolidone) (PS/PVP, with a 30/70 weight ratio) blends, that induces drastic blend morphology variation, is reported. The silver nanowires are fabricated with the anodic aluminum oxide templating method, and have a diameter of 300 nm and length of 10 µm. At a higher nanowire loading of 10 wt.‐%, the silver nanowires are entangled and selectively concentrate within the continuous PVP domain. If surface modified by thiols carrying hydrophobic tails, the silver nanowires become hydrophobic and prefer to stay within the discrete hydrophobic PS domains. At a lower nanowire loading of 5 wt.‐%, the nanowires are non‐entangled and concentrate at regions near the interfaces of the PS and PVP phases, which induces the formation of interconnected PS domains.

Preferential partition of silver nanowires in thin films of PS/PVP (30/70) blends at a casting temperature of −10 °C.

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Preferential partition of silver nanowires in thin films of PS/PVP (30/70) blends at a casting temperature of −10 °C.
Red Blood Cell Templated Polyelectrolyte Capsules: A Novel Vehicle for the Stable Encapsulation of DNA and Proteins
Authors: Kreft Oliver , Georgieva Radostina , Bäumler Hans , Steup Martin , Müller‐Röber Bernd , Sukhorukov Gleb B. , Möhwald Helmuth
Published: March 2006

Summary: A novel method for the encapsulation of biomacromolecules, such as nucleic acids and proteins, into polyelectrolyte microcapsules is described. Fluorescence‐labelled double‐stranded DNA and human serum albumin (HSA) are used as model substances for encapsulation in hollow microcapsules templated on human erythrocytes. The encapsulation procedure involves an intermediate drying step. The accumulation of DNA and HSA in the capsules is observed by confocal laser scanning microscopy, UV spectroscopy, and fluorimetry. The mechanism of encapsulation is discussed.

Confocal fluorescence microscopy images of encapsulated TRITC‐HSA (left) and dsDNA (right). Inserts demonstrate fluorescence profiles for both compounds.

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Confocal fluorescence microscopy images of encapsulated TRITC‐HSA (left) and dsDNA (right). Inserts demonstrate fluorescence profiles for both compounds.
Cross‐Linked Alq3‐Containing Polymers with Improved Electroluminescence Efficiency Used for OLEDs
Authors: Du Naiying , Tian Renyu , Peng Junbiao , Mei Qunbo , Lu Mangeng
Published: March 2006

Summary: Homopolymers and a series of copolymers with tris‐8‐hydroxyquinoline aluminum (Alq3) as the cross‐links are synthesized. All these polymers show improved electroluminescence (EL) efficiency over their previously reported counterparts. Among them, the copolymers containing Alq3 and carbazole groups show higher EL efficiency than that of the homopolymers. We also demonstrate the feasibility of generating patterns using the homopolymers via photopolymerization. The cross‐linked nature, selectivity of patterning, high thermal stability, and EL efficiency might render these polymers a promising material in fabricating large‐scaled multilayered sub‐pixellation organic light‐emitting diodes (OLEDs).

Current–voltage and the electroluminescence–voltage curve of two‐layer devices for the Alq3‐homopolymers and the Alq3‐copolymers (luminance is shown by the symbols without lines).

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Current–voltage and the electroluminescence–voltage curve of two‐layer devices for the Alq3‐homopolymers and the Alq3‐copolymers (luminance is shown by the symbols without lines).
Morphologies of Spin‐Coated Films of a Library of Diblock Copoly(2‐oxazoline)s and Their Correlation to the Corresponding Surface Energies
Authors: Hoeppener Stephanie , Wiesbrock Frank , Hoogenboom Richard , Thijs Hanneke M. L. , Schubert Ulrich S.
Published: March 2006

Summary: The influence of surface morphologies on the properties of materials is of essential importance and is therefore a widely discussed topic. In the present contribution, the properties of a set of diblock copoly(2‐oxazoline)s are analyzed in terms of their individual morphologies, which have been investigated with tapping‐mode SFM. This collection of diblock copolymers consists of 12 diblock copolymers and four corresponding homopolymers, representing a complete 16‐membered library of (co‐) poly(2‐oxazoline)s, composed of four differently substituted 2‐oxazoline monomers. For the investigated set of compounds, a correlation between the morphologies of the spin‐coated films and their surface energies could be determined.

Morphologies of spin‐coated films of a library of diblock copoly(2‐oxazoline)s and their correlation to the corresponding surface energies.

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Morphologies of spin‐coated films of a library of diblock copoly(2‐oxazoline)s and their correlation to the corresponding surface energies.
Cover Picture: Macromol. Symp. 233/2006
Authors: Weber Martin , Heckmann Walter , Goeldel Andreas
Published: March 2006

Cover: The design and synthesis of base materials is a necessary step for innovation on materials and processes. Synergies can be achieved by appropriate combinations of these materials in a wide variety of forms and shapes, and for a large range of applications. This was the main topic of the first joint meeting 8th European Symposium on Polymer Blends and Eurofillers 2005, showing that problems concerning ‘filled polymers’ and ‘polymer blends’ are often very similar and deserve attention from both scientific communities. As an example, the picture shows a TEM image of a styrenics/polyamide blend by reactive blending, taken from the contribution by M. Weber et al.
Blinded placebo crossover study of gabapentin in primary orthostatic tremor
Authors: Rodrigues Julian P. , Edwards Dylan J. , Walters Susan E. , Byrnes Michelle L. , Thickbroom Gary W. , Stell Rick , Mastaglia Frank L.
Published: March 2006

Primary orthostatic tremor (OT) is a rare but disabling condition characterized by leg tremor and feelings of instability during stance. Previous studies have reported a reduction in OT symptoms with gabapentin treatment. In this study, we report on the benefits of gabapentin treatment in a double‐blind placebo‐controlled crossover study of 6 OT patients. First, the maximally effective gabapentin dosage (600–2,700 mg/day) for each patient was determined during an initial dose‐titration phase. Patients were then studied 7 days after drug withdrawal and again after two 2‐week periods of treatment with either gabapentin or placebo, using force platform posturography to quantify postural sway and tremor. Other medications for OT were continued unchanged. Symptomatic response was assessed by a patient‐rated severity scale and quality of life (QOL) questionnaire. All patients reported an increase in symptoms during the washout phase and symptom reduction (50%–75%) during gabapentin treatment. Tremor amplitude was reduced to 79% ± 11% and sway area to 71% ± 11% of the placebo state. QOL improved in all patients, no adverse drug effects were noted, and symptomatic benefit was maintained at follow‐up (mean = 19 months). The findings confirm that gabapentin is an effective treatment for OT, reducing both tremor and postural instability and improving quality of life, and support its use as add‐on or first‐line therapy for OT. © 2006 Movement Disorder Society
Arc de cercle and dysautonomia from anoxic injury
Authors: Diesing T. Scott , Wijdicks Eelco F.M.
Published: March 2006

Autonomic dysregulation and catatonic posturing are well described following acute cerebral injury. Others have referred to this as diencephalic seizures, sympathetic storms, midbrain dysregulatory syndrome, and, most recently, paroxysmal autonomic instability with dystonia. Some of these syndromes can evolve into malignant catatonia requiring electroconvulsive therapy. Here we report a case of hanging associated anoxic brain injury resulting in severe dysautonomia and an extreme opisthotonus (arc de cercle). © 2006 Movement Disorder Society
The Arabic ICIQ‐UI SF: An alternative language version of the English ICIQ‐UI SF
Authors: Hashim H. , Avery K. , Mourad M.S. , Chamssuddin A. , Ghoniem G. , Abrams P.
Published: March 2006

Aims

Urinary incontinence (UI) is a common and distressing condition. A variety of questionnaires are currently available to assess UI and its impact on patients' lives. However, most have not been adapted for international use. Following a systematic review of the literature and existing questionnaires the International Consultation on Incontinence short form questionnaire (ICIQ‐UI SF) was developed, and has since been translated into many languages for local use. This paper reports the development and validation of the first UI questionnaire in the Arabic language. The development of this questionnaire will facilitate the assessment of UI in both clinical practice and research in the Middle‐East.

Methods

Translation and validation of the Arabic version of the ICIQ‐UI is described. Standard methods of translation by native Arabic and English speakers (including translation and back translation) are followed. The psychometric properties of the questionnaire, including its validity, reliability and sensitivity to change, are examined. The validation of the questionnaire involved patients attending urology outpatient clinics in two Middle‐Eastern countries.

Results

The Arabic ICIQ‐UI SF was found to be valid, reliable and responsive, indicating that the psychometric properties of the questionnaire have remained constant throughout the adaptation process. Furthermore, the findings of the psychometric testing confirm those found for the UK‐English ICIQ‐UI SF.

Conclusions

The development of this questionnaire will allow the study of Arabic speaking groups with UI in many countries around the world. This may act as an example to initiate the translation and validation of other patient reported outcomes into the Arabic language, thereby enabling more multinational and cross‐cultural research into diseases in given areas. Neurourol. Urodynam. 25:277–282, 2006. © 2006 Wiley‐Liss, Inc.
Three‐dimensional characterization of non‐gaussian water diffusion in humans using diffusion kurtosis imaging
Authors: Lu Hanzhang , Jensen Jens H. , Ramani Anita , Helpern Joseph A.
Published: March 2006

Conventional diffusion tensor imaging (DTI) measures water diffusion parameters based on the assumption that the spin displacement distribution is a Gaussian function. However, water movement in biological tissue is often non‐Gaussian and this non‐Gaussian behavior may contain useful information related to tissue structure and pathophysiology. Here we propose an approach to directly measure the non‐Gaussian property of water diffusion, characterized by a four‐dimensional matrix referred to as the diffusion kurtosis tensor. This approach does not require the complete measurement of the displacement distribution function and, therefore, is more time efficient compared with the q‐space imaging technique. A theoretical framework of the DK calculation is established, and experimental results are presented for humans obtained within a clinically feasible time of about 10 min. The resulting kurtosis maps are shown to be robust and reproducible. Directionally‐averaged apparent kurtosis coefficients (AKC, a unitless parameter) are 0.74 ± 0.03, 1.09 ± 0.01 and 0.84 ± 0.02 for gray matter, white matter and thalamus, respectively. The three‐dimensional kurtosis angular plots show tissue‐specific geometry for different brain regions and demonstrate the potential of identifying multiple fiber structures in a single voxel. Diffusion kurtosis imaging is a useful method to study non‐Gaussian diffusion behavior and can provide complementary information to that of DTI. Copyright © 2006 John Wiley & Sons, Ltd.
Theoretical analysis of carbon‐13 magnetization transfer for in vivo exchange between α‐ketoglutarate and glutamate
Authors: Shen Jun , Xu Su
Published: March 2006

Many enzymes catalyze fast exchange between a small pool and a large pool in vivo. For example, aspartate aminotransferase catalyzes fast exchanges between α‐ketoglutarate and glutamate and between oxaloacetate and aspartate, which can be detected using in vivo13C MRS while saturating α‐carbons of the keto acids. Unlike in the traditional saturation transfer experiments studied using 31P MRS, the tricarboxylic acid cycle intermediates α‐ketoglutarate and oxaloacetate are below the detection limit of in vivo NMR. In this work, a theoretical analysis of the saturation transfer between α‐ketoglutarate and glutamate catalyzed by aspartate aminotransferase was presented to examine the requirements for complete saturation of the rapidly turning over α‐ketoglutarate pool without affecting the longitudinal magnetization of glutamate. The fast turnover of the small α‐ketoglutarate pool also allows a quasi‐steady‐state approximation of its dynamic longitudinal relaxation. The theoretical analysis provides a useful guide for designing experimental methods to characterize saturation transfer processes associated with fast turning over small pools in vivo. Copyright © 2006 John Wiley & Sons, Ltd.
Liver fibrosis: non‐invasive assessment with MR elastography
Authors: Huwart Laurent , Peeters Frank , Sinkus Ralph , Annet Laurence , Salameh Najat , ter Beek Leon C. , Horsmans Yves , Van Beers Bernard E.
Published: March 2006

The aim of this study was to assess the feasibility of using non‐invasive MR elastography for determining the stage of liver fibrosis. Twenty‐five consecutive patients who had liver biopsy for suspicion of chronic liver disease were included in the study. The stage of fibrosis on the biopsies was assessed according to the METAVIR scoring system from F0, no fibrosis, to F4, cirrhosis. MR elastography was performed by transmitting low‐frequency (65 Hz) mechanical waves into the liver with a transducer placed at the back of the patients. The MR pulse sequence was a motion‐sensitized spin‐echo sequence, phase‐locked to the mechanical excitation. The phase maps were processed to obtain shear elasticity and shear viscosity maps. The mean hepatic shear elasticity increased with increasing stage of fibrosis. The mean elasticity was 2.24 ± 0.23 kPa in the 11 patients without substantial fibrosis (F0–F1 grades), 2.56 ± 0.24 kPa in the four patients with substantial fibrosis (F2–F3) and 4.68 ± 1.61 kPa in the 10 patients with cirrhosis (F4). The differences between groups were statistically significant (p ≤ 0.05). The mean shear viscosity was significantly higher in the patients with cirrhosis (5.19 ± 1.85 Pa · s) than in the patients without cirrhosis (2.39 ± 0.86 Pa · s in F0–F1 and 2.27 ± 0.38 Pa · s in F2–F3 patients). It is concluded that non‐invasive MR elastography is a feasible method to assess the stage of liver fibrosis. Copyright © 2006 John Wiley & Sons, Ltd.
Improving the reliability and throughput of mass spectrometry‐based proteomics by spectrum quality filtering
Authors: Flikka Kristian , Martens Lennart , Vandekerckhove Joël , Gevaert Kris , Eidhammer Ingvar
Published: March 2006

In contemporary peptide‐centric or non‐gel proteome studies, vast amounts of peptide fragmentation data are generated of which only a small part leads to peptide or protein identification. This motivates the development and use of a filtering algorithm that removes spectra that contribute little to protein identification. Removal of unidentifiable spectra reduced both the amount of computational and human time spent on analyzing spectra as well as the chances of obtaining false identifications. Thorough testing on various proteome datasets from different instruments showed that the best suggested machine‐learning classifier is, on average, able to recognize half of the unidentified spectra as bad spectra. Further analyses showed that several unidentified spectra classified as good were derived from peptides carrying unanticipated amino acid modifications or contained sequence tags that allowed peptide identification using homology searches. The implementation of the classifiers is available under the GNU General Public License at http://www.bioinfo.no/software/spectrumquality.
Microporous polyurethanes: Synthesis and investigation of the mechanism of the pore formation
Authors: Deepa P. , Jayakannan M.
Published: March 2006

A new approach for microporous polymeric material is developed utilizing the secondary interactions such as hydrogen bonding in the polymer chains in polyurethane systems at ambient conditions. A new series of highly rigid, thermally stable, and readily soluble cycloaliphatic polyurethanes were designed and synthesized for this purpose, based on new tricyclodecanedimethanol and 1,4‐cyclohexanedimethanol. The hydrogen‐bonding interactions induce phase separation in solution, which leads to polymer‐rich and solvent‐rich domains; subsequent evaporation of the solvent molecules results in micropores. The phase‐separation process in the polyurethane is found to be highly dependent on the chemical structures of the polymer chain backbone. 1H NMR titration experiments were carried out to understand the mechanism of the micropore formation and its dependence on different structural subunits. The hydrogen‐bonding association constant (K) obtained from the titration experiments revealed that higher the K‐value more the tendency to form micropores. A fully cycloaliphatic polyurethane produces micropores of sizes ranging from 1 to 8 μm, and each pore is separated by 10−20 μm, whereas the replacement of one of the cyclic unit in the backbone disturbs the entire phase‐separation process and results in nonporous morphology. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1296–1308, 2006