bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and validation of stir bar sorptive extraction of polar phenols in water followed by HPLC separation in poly(vinylpyrrolididone‐divinylbenzene) monolith
Authors: Huang Xiaojia , Qiu Ningning , Yuan Dongxing
Published: April 2009

An effective and simple method for polar phenols in water matrix was developed by using stir bar sorptive extraction (SBSE) based on a hydrophilic poly(vinylpyrrolididone‐divinylbenzene) (VPDB) monolithic material and HPLC analysis. To achieve optimum extraction performance for phenols, several parameters, including extraction and desorption time, desorption solvent, pH value, and ionic strength of sample matrix, were investigated. Under the optimized experimental conditions, eight phenols were directly enriched from water samples and analyzed by HPLC‐DAD. The detection limits (S/N = 3) and quantification limits (S/N = 10) of the proposed method for the target compounds were achieved within the range of 0.72–1.37 and 2.40–4.27 ng/mL from spiked water, respectively. Recoveries of eight phenolic compounds were found in the range of 55.2–95.9%. The calibration curves showed the linearity ranging from 5 to 150 ng/mL with linear regression coefficient R2 values above 0.98. Method repeatability presented as intra‐ and interday precisions were also found with the RSDs less than 4.10 and 7.61%, respectively. The distribution coefficients between VPDB and water (KVPDB/W) for phenolic compounds were also calculated and compared with KO/W. Finally, the proposed method was successfully applied to the determination of the target compounds in tap water, sea water and wastewater samples.
Macromol. Rapid Commun. 8/2009
Authors: Cui Liying , Zhang Youzhuan , Wang Jingxia , Ren Yibing , Song Yanlin , Jiang Lei
Published: April 2009

Front Cover: An ultra‐fast fabrication of colloidal photonic crystals by spray coating is shown. The schematic illustration of the method, the colorful colloidal photonic crystals and the typical scanning electron microscopy images are demonstrated. Further details can be found in the article by L. Cui, Y. Zhang, J. Wang,* Y. Ren, Y. Song,* and L. Jiang on page 598.
Macromol. Rapid Commun. 8/2009
Authors: Chiper Manuela , Hoogenboom Richard , Schubert Ulrich S.
Published: April 2009

Back Cover: The concept of building metallo‐supramolecular polymers based on chelating terpyridyl ligands is shown. The resulting supramolecular polymers represent a versatile class of materials in which the properties can be tuned by varying, for example, the metal ion and counter ion. Further details can be found in the article by M. Chiper, R. Hoogenboom, and U. S. Schubert* on page 565.
No somatic genetic change in the paxillin gene in nonsmall‐cell lung cancer
Authors: Pallier Karine , Houllier Anne‐Marie , Le Corre Delphine , Cazes Aurélie , Laurent‐Puig Pierre , Blons Hélène
Published: April 2009

The paxillin gene (PXN) encodes a focal adhesion associated protein that could be involved in the progression of lung cancer through its interactions with the actin cytoskeleton and key signal transduction oncogenes. PXN mutations and PXN amplifications were recently identified in nonsmall‐cell lung cancer (NSCLC) and amplifications were associated with MET increased copy number. The description of tumors with two to three mutations in the PXN gene and the overrepresentation of GC to AT transitions were unexpected and needed confirmation. The aim of this study was to validate the incidence of PXN somatic alterations in NSCLC and to correlate them to other common genetic alterations. PXN mutations and copy number changes at PXN, EGFR, and MET loci were analyzed on DNAs from frozen tumor samples (n = 159) that had been previously screened for mutations at EGFR, KRAS, BRAF, ERBB2, STK11, PIK3CA, and TP53. We found PXN polymorphisms including nonsynonymous ones but no PXN amplification and only 1/159 (<1%) somatic tumor mutation F416L. In conclusion, we do not deny the possible involvement of PXN in cancer but our findings do not support a major role for PXN somatic changes in lung carcinogenesis. © 2009 Wiley‐Liss, Inc.
Gender differences in the association between antidepressant use and restless legs syndrome
Authors: Baughman Kristin R. , Bourguet Claire C. , Ober Scott K.
Published: April 2009

Contradictory results have been reported for the association between antidepressant use and Restless Legs Syndrome (RLS). Our aim was to clarify the relationship and examine possible gender differences. We interviewed 1,693 veterans receiving primary care from the Cleveland VA Medical Center and obtained prescription drug information from their medical records. Overall, use of an antidepressant was associated with RLS for men (RR = 1.77, CI = 1.26, 2.48) but not for women (RR = 0.79, CI = 0.43, 1.47). Analyses of individual antidepressants revealed an association between RLS and fluoxetine for women (RR = 2.47, CI = 1.33, 4.56), and associations between RLS and citalopram, (RR = 2.09, CI = 1.20, 3.64), paroxetine (RR = 1.97, CI = 1.02, 3.79), and amitriptyline (RR = 2.40, CI = 1.45, 4.00) for men. We conclude that RLS may be associated with antidepressant use, but the association varies by gender and type of antidepressant. Antidepressant use is more strongly associated with RLS in men than in women. © 2009 Movement Disorder Society
Hyposmia and executive dysfunction as predictors of future Parkinson's disease: A prospective study
Authors: Ponsen Mirthe M. , Stoffers Diederick , Twisk Jos W.R. , Wolters Erik Ch. , Berendse Henk W.
Published: April 2009

Olfactory deficits and executive dysfunction are early and common symptoms in Parkinson's disease (PD). Previous studies have shown that hyposmia can be a first sign of PD. The aim of the present study was to determine which of three olfactory tests and two selected tests of executive function would be the best predictor of future PD over a 5 year period. In a cohort of 361 nonparkinsonian, nondemented first‐degree relatives of PD patients, in whom alternative causes of olfactory dysfunction were excluded, we measured baseline performance on three olfactory and two executive function tasks. Five years from baseline, clinical neurological evaluation and/or a screening questionnaire, sensitive to the presence of Parkinsonism, were used to detect individuals developing clinical PD. Our results show that in first degree relatives of PD patients worse performance on each of three olfactory processing tasks was associated with an increased risk of developing PD within 5 years, whereas performance on selected tests of executive dysfunction was not associated with an increased risk of developing PD. Interestingly, impaired odor discrimination was the best predictor for future PD. © 2009 Movement Disorder Society
A basic tool for risk assessment: A new method for the analysis of ergot alkaloids in rye and selected rye products
Authors: Müller Carola , Kemmlein Sabine , Klaffke Horst , Krauthause Werner , Preiß‐Weigert Angelika , Wittkowski Reiner
Published: April 2009

As a basis for the collection of occurrence and exposure data of ergot alkaloids in food, an HPLC method coupled with fluorimetric detection (HPLC‐FLD) for the determination of 12 pharmacologically active ergot alkaloids in rye and rye products was developed. Samples were extracted with a mixture of ethyl acetate, methanol, and aqueous ammonia, followed by centrifugation and purification by solid phase filtration (SPF) with basic alumina. After solvent adjustment, the samples were analyzed by HPLC‐FLD using a phenyl–hexyl‐column. Recoveries for five major alkaloids were between 89.3% (ergotamine) and 99.8% (α‐ergokryptine) with a maximum LOQ of 3.3 μg/kg (ergometrine). Precision expressed as RSD ranged from 2.8% (ergocristine) to 12.4% (α‐ergokryptine) for repeatability, and from 6.5% (ergocornine) to 14.9% (ergotamine) for within‐laboratory reproducibility, respectively. In a survey of 39 rye product samples, ergocristine and ergotamine were found to be the major alkaloids in commercially available rye products with contents of 127 μg/kg (ergocristine), and 134 μg/kg (ergotamine) in rye flour, and 152.5 and 117.8 μg/kg in coarse meal, respectively.
Rapid water and lipid imaging with T2 mapping using a radial IDEAL‐GRASE technique
Authors: Li Zhiqiang , Graff Christian , Gmitro Arthur F. , Squire Scott W. , Bilgin Ali , Outwater Eric K. , Altbach Maria I.
Published: April 2009

Three‐point Dixon methods have been investigated as a means to generate water and fat images without the effects of field inhomogeneities. Recently, an iterative algorithm (IDEAL, iterative decomposition of water and fat with echo asymmetry and least squares estimation) was combined with a gradient and spin‐echo acquisition strategy (IDEAL‐GRASE) to provide a time‐efficient method for lipid–water imaging with correction for the effects of field inhomogeneities. The method presented in this work combines IDEAL‐GRASE with radial data acquisition. Radial data sampling offers robustness to motion over Cartesian trajectories as well as the possibility of generating high‐resolution T2 maps in addition to the water and fat images. The radial IDEAL‐GRASE technique is demonstrated in phantoms and in vivo for various applications including abdominal, pelvic, and cardiac imaging. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Hyperpolarized lithium‐6 as a sensor of nanomolar contrast agents
Authors: van Heeswijk Ruud B. , Uffmann Kai , Comment Arnaud , Kurdzesau Fiodar , Perazzolo Chiara , Cudalbu Cristina , Jannin Sami , Konter Jacobus A. , Hautle Patrick , van den Brandt Ben , Navon Gil , van der Klink Jacques J. , Gruetter Rolf
Published: April 2009

Lithium is widely used in psychotherapy. The 6Li isotope has a long intrinsic longitudinal relaxation time T1 on the order of minutes, making it an ideal candidate for hyperpolarization experiments. In the present study we demonstrated that lithium‐6 can be readily hyperpolarized within 30 min, while retaining a long polarization decay time on the order of a minute. We used the intrinsically long relaxation time for the detection of 500 nM contrast agent in vitro. Hyperpolarized lithium‐6 was administered to the rat and its signal retained a decay time on the order of 70 sec in vivo. Localization experiments imply that the lithium signal originated from within the brain and that it was detectable up to 5 min after administration. We conclude that the detection of submicromolar contrast agents using hyperpolarized NMR nuclei such as 6Li may provide a novel avenue for molecular imaging. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
MR elastography as a method for the assessment of myocardial stiffness: Comparison with an established pressure–volume model in a left ventricular model of the heart
Authors: Kolipaka Arunark , McGee Kiaran P. , Araoz Philip A. , Glaser Kevin J. , Manduca Armando , Romano Anthony J. , Ehman Richard L.
Published: April 2009

Magnetic resonance elastography (MRE) measurements of shear stiffness (μ) in a spherical phantom experiencing both static and cyclic pressure variations were compared to those derived from an established pressure–volume (P‐V)‐based model. A spherical phantom was constructed using a silicone rubber composite of 10 cm inner diameter and 1.3 cm thickness. A gradient echo MRE sequence was used to determine μ within the phantom at static and cyclic pressures ranging from 55 to 90 mmHg. Average values of μ using MRE were obtained within a region of interest and were compared to the P‐V‐derived estimates. Under both static and cyclic pressure conditions, the P‐V‐ and MRE‐based estimates of μ ranged from 98.2 to 155.1 kPa and 96.2 to 150.8 kPa, respectively. Correlation coefficients (R2) of 0.98 and 0.97 between the P‐V and MRE‐based estimates of shear stiffness measurements were obtained. For both static and cyclic pressures, MRE‐based measures of μ agree with those derived from a P‐V model, suggesting that MRE can be used as a new, noninvasive method of assessing μ in sphere‐like fluid‐filled organs such as the heart. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Noninvasive quantification of whole‐brain cerebral metabolic rate of oxygen (CMRO2) by MRI
Authors: Xu Feng , Ge Yulin , Lu Hanzhang
Published: April 2009

Cerebral metabolic rate of oxygen (CMRO2) is an important marker for brain function and brain health. Existing techniques for quantification of CMRO2 with positron emission tomography (PET) or MRI involve special equipment and/or exogenous agents, and may not be suitable for routine clinical studies. In the present study, a noninvasive method is developed to estimate whole‐brain CMRO2 in humans. This method applies phase‐contrast MRI for quantitative blood flow measurement and T2‐relaxation‐under‐spin‐tagging (TRUST) MRI for venous oxygenation estimation, and uses the Fick principle of arteriovenous difference for the calculation of CMRO2. Whole‐brain averaged CMRO2 values in young, healthy subjects were 132.1 ± 20.0 μmol/100 g/min, in good agreement with literature reports using PET. Various acquisition strategies for phase‐contrast and TRUST MRI were compared, and it was found that nongated phase‐contrast and sagittal sinus (SS) TRUST MRI were able to provide the most efficient and accurate estimation of CMRO2. In addition, blood flow and venous oxygenation were found to be positively correlated across subjects. Owing to the noninvasive nature of this method, it may be a convenient and useful approach for assessment of brain metabolism in brain disorders as well as under various physiologic conditions. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Temporally constrained reconstruction applied to MRI temperature data
Authors: Todd Nick , Adluru Ganesh , Payne Allison , DiBella Edward V.R. , Parker Dennis
Published: April 2009

The monitoring of thermal ablation procedures would benefit from an acceleration in the rate at which MRI temperature maps are acquired. Constrained reconstruction techniques have been shown to be capable of generating high quality images using only a fraction of the k‐space data. Here, we present a temporally constrained reconstruction (TCR) algorithm applied to proton resonance frequency shift (PRF) data. The algorithm generates images from undersampled data by iteratively minimizing a cost function. The unique challenges of using an iterative constrained reconstruction technique to generate real‐time images were addressed. For a set of eight heating experiments on ex vivo porcine tissue, a maximum reduction factor of 4 was achieved while keeping the root mean square error (RMSE) of the temperature below 0.5°C. For a set of three heating experiments on in vivo canine muscle tissue, the maximum reduction factor achieved was 3 while keeping the temperature RMSE below 1.0°C. At these reduction factors, the TCR algorithm underpredicted the thermal dose by an average of 6% for the ex vivo data and 28% for the in vivo data. Compared with sliding window and low resolution reconstructions, the RMSE of the TCR algorithm was significantly lower (P < 0.05 in all cases). Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
A note on fast approximate minimum degree orderings for symmetric matrices with some dense rows
Authors: Dollar H. S. , Scott J. A.
Published: April 2009

Recently, a number of variants of the approximate minimum degree algorithm have been proposed that aim to efficiently order symmetric matrices containing some dense rows. We compare the performance of these variants on a range of problems and highlight their potential limitations. This leads us to propose a new variant that offers both speed and robustness. Copyright © 2009 John Wiley & Sons, Ltd.
A meshless method using the radial basis functions for numerical solution of the regularized long wave equation
Authors: Shokri Ali , Dehghan Mehdi
Published: April 2009

This article discusses on the solution of the regularized long wave (RLW) equation, which is introduced to describe the development of the undular bore, has been used for modeling in many branches of science and engineering. A numerical method is presented to solve the RLW equation. The main idea behind this numerical simulation is to use the collocation and approximating the solution by radial basis functions (RBFs). To avoid solving the nonlinear system, a predictor‐corrector scheme is proposed. Several test problems are given to validate the new technique. The numerical simulation, includes the propagation of a solitary wave, interaction of two positive solitary waves, interaction of a positive and a negative solitary wave, the evaluation of Maxwellian pulse into stable solitary waves and the development of an undular bore. The three invariants of the motion are calculated to determine the conservation properties of the algorithm. The results of numerical experiments are compared with analytical solution and with those of other recently published methods to confirm the accuracy and efficiency of the presented scheme.© 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
Compatibility of softwood flour and commercial biopolymers in injection molding
Authors: Sykacek Eva , Schlager Wolfgang , Mundigler Norbert
Published: April 2009

This study is focused on wood flour‐reinforced biopolymers for injection molding. Eight commercial biopolymers were compounded with 30 and 50% wood flour and injection molded. Thermal processability via extrusion was evaluated by use of the resulting melt pressure, melt temperature, and machine load, during injection molding the injection pressure was taken. Clear increases of melt‐ and injection pressures could be determined at rising fiber load and better shaping of the molded parts was observed. The mechanical performance of the composites and the neat polymers was evaluated by tensile‐, bending‐, and impact properties. To study the effects of different fiber concentrations, multiple comparison tests were calculated. High variations in the mechanical properties and in hygroscopic behavior were found between the different biopolymers. Through incorporation of wood flour, the E‐modules of all polymers were significantly improved. The strength values of the various biopolymers offered different trends because of the reinforcement. The polylactic acid (PLA) and the cellulose‐based polymer Biograde showed significant decreases in strength by addition of wood flour. Scanning electron micrographs of a 50% filled PLA compound revealed low fiber matrix adhesion. Impactstrength and elongation at yield of all investigated polymers dropped dramatically with rising fiber content. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Effects of carbon fillers in thermally conductive polypropylene based resins
Authors: King Julia A. , Johnson Beth A. , Via Michael D. , Ciarkowski Charles J.
Published: April 2009

The thermal conductivity of insulating polymers can be increased by adding conductive fillers. One potential market for these thermally conductive resins is for fuel cell bipolar plates. In this study, varying amounts of three different carbon fillers (carbon black, synthetic graphite particles, and carbon nanotubes) were added to polypropylene. The effects of single fillers and combinations of the different fillers were studied via a factorial design. Each single filler caused a statistically significant increase in composite through‐plane thermal conductivity at the 95% confidence level, with synthetic graphite causing the largest increase. All of the composites containing combinations of the different fillers caused a statistically significant increase in composite through‐plane thermal conductivity. It is possible that thermally conductive pathways are formed that ‘link’ these carbon fillers, which results in increased composite thermal conductivity. Composites containing 80 wt% synthetic graphite had an in‐plane thermal conductivity of 28.0 W/m·K, which is desired for bipolar plates (>20 W/m·K). POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Prenatal screening for chromosome abnormalities in a region with no access to termination of pregnancy
Authors: Paolini Cynthia I. , Gadow Andrea , Petracchi Florencia , Igarzabal Laura , Quadrelli Roberto , Gadow Enrique C.
Published: April 2009

Objective

To analyze the different variables that affect couples' decision‐making about prenatal screening of chromosome abnormalities in a population with limited access to prenatal diagnosis and no legal termination of pregnancy (TOP).

Methods

From February through August 2004, 79 couples who requested for prenatal screening at centers from Argentina and Uruguay participated in a study. A cross‐sectional survey was administered to assess attitudes toward prenatal screening, the decision‐making process, and knowledge and attitudes toward TOP.

Results

Mean maternal age was 32.8 ± 0.4 years. Among the couples, 88.61% knew that TOP due to fetal anomalies is not legal in their countries. When asked about the possibility of TOP in case of a serious fetal anomaly, 53% would contemplate this option.

Conclusion

Prenatal screening is a common practice worldwide. However, unlike most developed countries, our region has a limited access to prenatal diagnosis and no legal TOP. Those couples who stated that ‘reassurance about fetal well‐being’ was the most important reason to perform prenatal screening had more positive attitudes toward TOP than those who considered this screening important ‘to be better prepared to receive the baby’. Our findings can be used to inform and revise current health‐care policies. Copyright © 2009 John Wiley & Sons, Ltd.
(Meth)acrylate vinyl ester hybrid polymerizations
Authors: Lee Tai Yeon , Cramer Neil B. , Hoyle Charles E. , Stansbury Jeffrey W. , Bowman Christopher N.
Published: April 2009

In this study, vinyl ester monomers were synthesized by an amine catalyzed Michael addition reaction between a multifunctional thiol and the acrylate double bond of vinyl acrylate. The copolymerization behavior of both methacrylate/vinyl ester and acrylate/vinyl ester systems was studied with near‐infrared spectroscopy. In acrylate/vinyl ester systems, the acrylate groups polymerize faster than the vinyl ester groups resulting in an overall conversion of 80% for acrylate double bonds in the acrylate/vinyl ester system relative to only 50% in the bulk acrylate system. In the methacrylate/vinyl ester systems, the difference in reactivity is even more pronounced resulting in two distinguishable polymerization regimes, one dominated by methacrylate polymerization and a second dominated by vinyl ester polymerization. A faster polymerization rate and higher overall conversion of the methacrylate double bonds is thus achieved relative to polymerization of the pure methacrylate system. The methacrylate conversion in the methacrylate/vinyl ester system is near 100% compared to only ∼60% in the pure methacrylate system. Utilizing hydrophilic vinyl ester and hydrophobic methacrylate monomers, polymerization‐induced phase separation is observed. The phase separated domain size is in the order of ∼1 μm under the polymerization conditions. The phase separated domains become larger and more distinct with slower polymerization and correspondingly increased time for diffusion. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2509–2517, 2009
Ferrocenyl‐functionalized long chain branched polydienes
Authors: Wurm Frederik , Villanueva Francisco Javier López , Frey Holger
Published: April 2009

A convenient two‐step approach for the synthesis of ferrocenyl‐functionalized long chain branched polydienes, based on both butadiene and isoprene, respectively, is presented. Classical living anionic polymerization was used to synthesize different ABn type poly(diene) macromonomers with moderate molecular weights between 1700 and 3200 g/mol and narrow polydispersity. Quantitative end‐capping with chlorodimethylsilane resulted in the desired ABn macromonomer structures. In the ensuing Pt‐catalyzed hydrosilylation polyaddition, branched, functionalized polydienes were obtained by a concurrent ABn + AR type of copolymerization with mono‐ and difunctional ferrocenyl silanes (fcSiMe2H or fc2SiMeH). Molecular weights of the branched polymers were in the range of 10,000 to 44,000 g/mol (SEC/MALLS). Because of the large number of functional end groups, high loading with ferrocene units up to 63 wt % of ferrocene was achieved. Detailed studies showed full conversion of the functional silanes and incorporation into the branched polymer. Further studies using DSC, TGA, and cyclovoltammetry (CV) measurements have been performed. Electrochemical studies demonstrated different electrochemical properties for fcSiMe2‐ and fc2SiMe‐units. The CVs of polymers modified with diferrocenylsilane units exhibit the pattern of communicating ferrocenyl sites with two distinct, separate oxidation waves. The polymers were also deposited on an electrode surface and the electrodes investigated via CV, showing formation of electroactive films with promising results for the use of the materials in biosensors. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2518–2529, 2009
Synthesis of amphiphilic copolymer brushes possessing alternating poly(methyl methacrylate) and poly(N‐isopropylacrylamide) grafts via a combination of ATRP and click chemistry
Authors: Yin Jun , Ge Zhishen , Liu Hao , Liu Shiyong
Published: April 2009

We report on the synthesis of well‐defined amphiphilic copolymer brushes possessing alternating poly(methyl methacrylate) and poly(N‐isopropylacrylamide) grafts, poly(PMMA‐alt‐PNIPAM), via a combination of atom transfer radical polymerization (ATRP) and click reaction (Scheme 1). Firstly, the alternating copolymerization of N‐[2‐(2‐bromoisobutyryloxy)ethyl]maleimide (BIBEMI) with 4‐vinylbenzyl azide (VBA) affords poly(BIBEMI‐alt‐VBA). Bearing bromine and azide moieties arranged in an alternating manner, multifunctional poly(BIBEMI‐alt‐VBA) is capable of initiating ATRP and participating in click reaction. The subsequent ATRP of methyl methacrylate (MMA) using poly(BIBEMI‐alt‐VBA) as the macroinitiator leads to poly(PMMA‐alt‐VBA) copolymer brush. Finally, amphiphilic poly(PMMA‐alt‐PNIPAM) copolymer brush bearing alternating PMMA and PNIPAM grafts is synthesized via the click reaction of poly(PMMA‐alt‐VBA) with an excess of alkynyl‐terminated PNIPAM (alkynyl‐PNIPAM). The click coupling efficiency of PNIPAM grafts is determined to be ∼80%. Differential scanning calorimetry (DSC) analysis of poly(PMMA‐alt‐PNIPAM) reveals two glass transition temperatures (Tg). In aqueous solution, poly(PMMA‐alt‐PNIPAM) supramolecularly self‐assembles into spherical micelles consisting of PMMA cores and thermoresponsive PNIPAM coronas, which were characterized via a combination of temperature‐dependent optical transmittance, micro‐differential scanning calorimetry (micro‐DSC), dynamic and static laser light scattering (LLS), and transmission electron microscopy (TEM). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2608–2619, 2009
Well‐defined poly[(dimethylamimo)ethyl methacrylate]‐b‐poly(fluoroalkyl methacrylate) diblock copolymers: Effects of different fluoroalkyl groups on the solution properties
Authors: Liu Cuicui , He Jinlin , Zhao Qun , Zhang Mingzu , Ni Peihong
Published: April 2009

A series of well‐defined, fluorinated diblock copolymers, poly[2‐(dimethylamino)ethyl methacrylate]‐b‐poly(2,2,2‐trifluoroethyl methacrylate) (PDMA‐b‐PTFMA), poly[2‐(dimethylamino)ethyl methacrylate]‐b‐poly(2,2,3,4,4,4‐hexafluorobutyl methacrylate) (PDMA‐b‐PHFMA), and poly[2‐(dimethylamino)ethyl methacrylate]‐b‐poly(2,2,3,3,4,4,5,5‐octafluoropentyl methacrylate) (PDMA‐b‐POFMA), have been synthesized successfully via oxyanion‐initiated polymerization. Potassium benzyl alcoholate (BzO−K+) was used to initiate DMA monomer to yield the first block PDMA. If not quenched, the first living chain could be subsequently used to initiate a feed F‐monomer (such as TFMA, HFMA, or OFMA) to produce diblock copolymers containing different poly(fluoroalkyl methacrylate) moieties. The composition and chemical structure of these fluorinated copolymers were confirmed by 1H NMR, 19F NMR spectroscopy, and gel permeation chromatography (GPC) techniques. The solution behaviors of these copolymers containing (tri‐, hexa‐, or octa‐ F‐atom)FMA were investigated by the measurements of surface tension, dynamic light scattering (DLS), and UV spectrophotometer. The results indicate that these fluorinated copolymers possess relatively high surface activity, especially at neutral media. Moreover, the DLS and UV measurements showed that these fluorinated diblock copolymers possess distinct pH/temperature‐responsive properties, depending not only on the PDMA segment but also on the fluoroalkyl structure of the FMA units. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2702–2712, 2009
Facile one‐pot synthesis and characterization of novel nanostructured organic dispersible polyaniline
Authors: Han Youn‐Gyu , Kusunose Takafumi , Sekino Tohru
Published: April 2009

Novel polyaniline (PANI) with nanotube, nanosheet, and nanofiber shapes was facilely synthesized by a self‐templating one‐pot process. Anilinium‐dodecylsulfate (DS) complex, obtained by mixing equivalent amounts of aniline and sodium dodecylsulfate (SDS), played a template‐like role in forming PANI nanostructures. It was found that the morphology and electrical conductivity of the PANI nanostructures changed with the amount of SDS and the reaction temperature. Nanotube‐shaped PANI synthesized at the temperature of anilinium‐DS complex formation in presence of SDS (concentration <0.12 M) showed high conductivity (12.9 S/cm). At higher temperature, the morphology changed to shape of a rose flower and electrical conductivity decreased to 3.95 S/cm. This suggested that both temperature and SDS concentration were key parameters for controlling the formation of the anilinium‐DS complex that acted as a template. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1024–1029, 2009
Piezoresistive characteristics of single wall carbon nanotube/polyimide nanocomposites
Authors: Kang Jin Ho , Park Cheol , Scholl Jonathan A. , Brazin Amy H. , Holloway Nancy M. , High James W. , Lowther Sharon E. , Harrison Joycelyn S.
Published: April 2009

A systematic study of the effect of single wall carbon nanotubes (SWCNTs) on the enhanced piezoresistive sensitivity of polyimide nanocomposites from below to above percolation was accomplished. The maximum piezoresistive stress coefficient (Π) of 1.52 × 10−3 MPa−1 was noted at just above the percolation threshold concentration (Φ ∼ 0.05 wt %) of SWCNT. This coefficient value exceeds those of metallic piezoresistive materials by two orders of magnitude (4.25 × 10−5 MPa−1 for aluminum). The high piezoresistive characteristics appear to originate from a change in the intrinsic resistivity of the composite caused by the variation of the tunneling distance between conducting inclusions (SWCNTs) under compression or tension. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 994–1003, 2009
Reduction of Biofilm Formation on a‐C:H Coated Implants: Investigation of Biofilm‐Surface Interactions by Variation of Thin Film Properties
Authors: Kleinen Lisa , Syring Isabella , Laube Norbert
Published: April 2009

Formation of crystalline bacterial biofilms (encrustations) on urological implants remains a major complication in patient care. Recently, it was shown that amorphous carbon (a‐C:H) coatings deposited on polyurethane (PU) stents provide a distinct reduction in biofilm formation with an effect more pronounced in‐vivo than in‐vitro. To investigate the underlying mechanisms, the influence of surface properties on the encrustation tendency of plasma coated and uncoated PU tubes was tested in an extended in‐vitro model with protein‐spiked artificial urine and urease. In the presence of albumin the formation of hollow crystalline spheres was observed mainly on uncoated PU. We suggest that evolving gas bubbles influence protein adherence and attachment of crystalline bacterial biofilm to the implant surfaces.
Wear Behaviour of UHMWPE Against DC‐Pulsed Plasma Nitrided and Duplex Treated AISI 316L Used in Hip Joint Replacements
Authors: Perez Ezequiel , Pazos Leonardo , Heras Evangelina De Las , Parodi Belén , Corengia Pablo , Braceras Iñigo
Published: April 2009

Wear behaviour of the artificial joint replacements plays a critical role in implant failure. The UHMWPE‐AISI 316L tribological system, widely used on joint prostheses, was studied. Two surface modifications were applied to the stainless steel counterface: DC‐pulsed plasma nitriding and duplex (DC‐pulsed plasma nitriding + TiN coating by cathodic‐arc evaporation) treatments. An Amsler Disc Machine Type A‐135 was used as an approximation to real loading conditions. Worn surfaces, weight loss curves and wear debris were analysed. The results show that the nitriding and duplex treatments improve the wear resistance of the tribological system. Different types of damages were observed on the UHMWPE worn surfaces depending on the surface treatment of the stainless steel.
Chemical Composition of SiOx Films Deposited by an Atmospheric Pressure Plasma Jet (APPJ)
Authors: Schäfer Jan , Foest Rüdiger , Quade Antje , Ohl Andreas , Weltmann Klaus‐Dieter
Published: April 2009

SiOx films are deposited with an APPJ (27 MHz) using Ar, O2 and OMCTS [Si4O4(CH3)8]. An experimental study on the influence of the O2 versus OMCTS concentration on the chemical composition of the films and their radial gradients over the static deposition profile is carried out by means of XPS and ATR‐FT‐IR. The films are characterized by dominating SiO IR absorption and the absence of CH2 and CH3 bands, indicating the inorganic SiOx character. From the absorbance differences of the three SiO IR bands present in the spectra, the existence of different structural phases is derived. Over the examined parameter field, three different structural phases are distinguished. Their occurrence can be seen as a marker for the film quality and allows formulating optimal deposition conditions for defined structures of organosilicon films.
Unorthodox long‐term aerosolized ampicillin use for methicillin‐susceptible Staphylococcus aureus lung infection in a cystic fibrosis patient
Authors: Máiz Luis , Lamas Adelaida , Fernández‐Olmos Ana , Suárez Lucrecia , Cantón Rafael
Published: April 2009

Staphylococcus aureus is a significant cause of pulmonary colonization in cystic fibrosis (CF) patients. The optimal strategy of therapy in chronically infected patients with this pathogen is not yet established. We report a successful long‐term aerosolized ampicillin treatment of a 14‐year‐old girl with chronic symptomatic S. aureus lung infection. Pediatr Pulmonol. 2009; 44:512–515. © 2009 Wiley‐Liss, Inc.
History of process safety at OSHA
Authors: Long Lisa A.
Published: April 2009

Occupational Safety and Health Agency (OSHA)'s first major process safety regulation, 29 CFR 1910.119, Process Safety Management of Highly Hazardous Chemicals (PSM) was enacted in 1992. However, OSHA's experience with process safety began in the 1980s when a series of catastrophic chemical incidents occurred. Learnings from investigations of these incidents helped to shape PSM. More than 15 years after PSM, lessons from incidents and inspection experience continue to shape the history of process safety at OSHA. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2009
In situ bioremediation of organochlorine‐pesticide‐contaminated microcosm soil and evaluation by gene probe
Authors: Qureshi Asifa , Mohan M , Kanade Gajanan S , Kapley Atya , Purohit Hemant J
Published: April 2009

BACKGROUND: Pesticide‐formulating industries are contaminating the environment through various activities. Bioremediation is the best method for decontamination, as chemical and physical methods are not only costly but also not very effective in open field systems. In the present study, in situ bioremediation of organochlorine‐contaminated soil was demonstrated by combined biostimulation and bioaugmentation strategies, followed by evaluation using a molecular method.

RESULTS: Three parameters were monitored: microbial biomass (colony‐forming units (CFU) g−1 soil), residual pesticides after treatment and catabolic genes from microcosm soil. Both the biostimulation and the bioaugmentation treatments showed an initial lag phase of 80 days towards colony‐forming units. Gas chromatography of soil samples showed that concentrations of residual pesticides in the soil declined by up to 85–90% after 80 days, indicating their utilisation with time. On dot‐blot hybridisation of the total DNA from the same soil samples, it was observed that catabolic genes tfdC (catechol 1,2‐dioxygenase) and cm genes (chlorophenol monoxygenase) were predominant, whereas other catabolic genes such as catechol 2,3‐dioxygenase (xylE) were negligible.

CONCLUSION: The strategy of in situ bioremediation and its evaluation by gene probe and also by conventional methods was demonstrated for organochlorine‐pesticide‐contaminated soil in open microcosms. It showed that bioaugmentation along with biostimulation was effective, although initial acclimatisation for a period of almost 2–3 months was required in the open field systems. Copyright © 2009 Society of Chemical Industry
Dark current in multilayer stabilized amorphous selenium X‐ray photoconductors
Authors: Frey J. B. , Belev G. , Tousignant O. , Mani H. , Kasap S. O.
Published: April 2009

Commercially available flat panel, direct conversion, digital X‐ray image detectors use a photoconductive layer of stabilized amorphous selenium (a‐Se) sandwiched between two electrodes to convert incident X‐ray radiation into stored electrical charge. These detectors use thin n ‐like and p ‐like blocking layers to trap charge carriers injected from the contacts and thus reduce the dark current by limiting the rate of carrier injection. The effect of each of these blocking layers is determined by measuring the dark current in 200 μm thick mammographic detector‐like samples of a‐Se with three different structures: a single intrinsic layer and n‐i and i‐p double layers. Dark current is measured as a function of time over 20,000 s and as a function of applied electric field over the range of −10 V/μm to +10 V/μm. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exciton response controlled by introducing a spacer layer in nitrided InAs quantum dots
Authors: Mamizuka Masataka , Kojima Osamu , Inoue Tomoya , Kita Takashi , Wada Osamu
Published: April 2009

We demonstrate the control of the exciton dynamics in self‐assembled InAs quantum dots (QDs) by introducing a nitridation layer and a GaAs spacer layer on the QD surface. The PL intensity and decay time decrease owing to the introduction of the nitridation layer. Moreover, by inserting the GaAs spacer layer between the QD surface and the nitridation layer, the PL intensity of and decay time increase. These changes in PL characteristics correspond to that of the non‐radiative recombination rate caused by crystal defects. Our results imply that the exciton response time of InAs QDs can be controlled by the thickness of the spacer layer. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical results of the analytical and numerical solutions of superluminescent fiber sources
Authors: Sandoval‐Romero G. E. , Argueta‐Díaz V. , Pottiez O.
Published: April 2009

We present a theoretical study of superluminescent optical fiber‐sources; in this study we compare the results obtained from an analytic model and the numerical solutions of the rate equations that allow determining the output signal characteristics of such a light source. The characteristics on which we focus our interest are the total optical power, the spectral bandwidth, and the fiber length for maximum optical power. These light sources are of special interest as feed and pump sources in fiber sensors, gyroscopes, etc where spectral bandwidth and stability are of concern. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Absolute characterization of photoluminesence from pulsed‐laser deposited, sol‐gel, sputtered and evaporated ZnO thin films
Authors: Taschuk M. T. , LaForge J. M. , Nguyen H. , Sun Y. W. , Kursa P. , DeCorby R. G. , Brett M. J. , Tsui Y. Y.
Published: April 2009

ZnO thin films were fabricated using PLD, sputtering, e‐beam evaporation and sol‐gel techniques. The films were annealed in an oxygen environment to improve their crystallinity. Photoluminescence efficiency and angular emission patterns were characterized and are reported in absolute radiometric units. Conversion efficiencies in the range of 1 – 7 · 10‐6 were found for the PLD films, 7 · 10‐6 for a sputtered film, 7 – 40 · 10‐6 for the e‐beam evaporated films, and 20 – 400 · 10‐6 for the Sol‐Gel films. In most cases, the angular emission pattern of the photoluminescence was lambertian in nature. Non‐lambertian emission patterns were observed for some films with microstructure, achieved with PLD and e‐beam evaporation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deep levels in low‐energy electron‐irradiated 4H‐SiC
Authors: Carlsson P. , Son N.T. , Beyer F. C. , Pedersen H. , Isoya J. , Morishita N. , Ohshima T. , Janzén E.
Published: April 2009

Deep levels introduced by low‐energy (200 keV) electron irradiation in n‐type 4H‐SiC epitaxial layers grown by chemical vapour deposition were studied by deep level transient spectroscopy (DLTS) and photoexcitation electron paramagnetic resonance (photo‐EPR). After irradiation, several DLTS levels, EH1, EH3, Z1/2, EH5 and EH6/7, often reported in irradiated 4H‐SiC, were observed. In irradiated freestanding films from the same wafer, the EPR signals of the carbon vacancy in the positive and negative charge states, VC+ and VC‐, respectively, can be observed simultaneously under illumination with light of certain photon energies. Comparing the ionization energies obtained from DLTS and photo‐EPR, we suggest that the EH6/7 (at ∼EC – 1.6 eV) and EH5 (at ∼EC – 1.0 eV) electron traps may be related to the single donor (+ | 0) and the double acceptor (1– | 2–) level of VC, respectively. Judging from the relative intensity of the DLTS signals, the EH6/7 level may also be contributed to by other unidentified defects. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Accounting for non‐uniform static stability in orographic drag parametrization
Authors: Vosper S. B. , Wells H. , Brown A. R.
Published: April 2009

The extent to which the drag due to flow blocking by mountains is affected by height variations in the static stability is examined using a series of numerical simulations. The results are used to investigate how best to estimate the depth‐averaged upwind static stability for the purposes of parametrizing the drag. © Crown Copyright 2009. Reproduced with the permission of HMSO. Published by John Wiley & Sons, Ltd.
Embedding enterprise science into SSM for improving innovation systems in technology‐based companies
Authors: Löffler Karin , Tschirky Hugo , Kijima Kyoichi J.
Published: April 2009

The paper discusses how organizations can benefit from applying an enhanced Soft Systems Methodology (SSM) in innovation context. The combined approach is illustrated with an intervention in the innovation department of a multinational company. The aim of the company has been to increase its competitiveness by fostering innovation and questioning the innovation system of the company as well as the innovation project portfolio. Embedded in the SSM, the concept of Enterprise Science has been a useful vehicle to structure the problem situation and to channel the search for possible solutions. Innovation challenges could be pointed out, analysed and resolved in a systemic way. Lessons from practice are presented as well as recommendations for decision makers regarding the application of the approach and an outlook to further studies. Copyright © 2009 John Wiley & Sons, Ltd.
The lung physiome: merging imaging‐based measures with predictive computational models
Authors: Tawhai Merryn H. , Hoffman Eric A. , Lin Ching‐Long
Published: April 2009

Global measurements of the lung provided by standard pulmonary function tests do not give insight into the regional basis of lung function and lung disease. Advances in imaging methodologies, computer technologies, and subject‐specific simulations are creating new opportunities to study structure‐function relationships in the lung through multidisciplinary research. The digital Human Lung Atlas is an image‐based resource compiled from male and female subjects spanning several decades of age. The Atlas comprises both structural and functional measures, and includes computational models derived to match individual subjects for personalized prediction of function. The computational models in the Atlas form part of the Lung Physiome project, which is an international effort to develop integrative models of lung function at all levels of biological organization. The computational models provide mechanistic interpretation of imaging measures; the Atlas provides structural data on which to base model geometry, and functional data against which to test hypotheses. The example of simulating airflow on a subject‐specific basis is considered. Methods for deriving multiscale models of the airway geometry for individual subjects in the Atlas are outlined, and methods for modeling turbulent flows in the airway are reviewed. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Analytical and Computational Methods > Computational Methods

Models of Systems Properties and Processes > Organ, Tissue, and Physiological Models

Translational, Genomic, and Systems Medicine > Translational Medicine
Eukaryotic chemotaxis
Authors: Rappel Wouter‐Jan , Loomis William F.
Published: April 2009

During eukaryotic chemotaxis, external chemical gradients guide the crawling motion of cells. This process plays an important role in a large variety of biological systems and has wide ranging medical implications. New experimental techniques including confocal microscopy and microfluidics have advanced our understanding of chemotaxis while numerical modeling efforts are beginning to offer critical insights. In this short review, we survey the current experimental status of the field by dividing chemotaxis into three distinct ‘modules’: directional sensing, polarity and motility. For each module, we attempt to point out potential new directions of research and discuss how modeling studies interact with experimental investigations. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Models of Systems Properties and Processes > Cellular Models
Tetraallylsilane π–Complexation: Synthesis and Structure of [Cu5Cl5(CH2–CH=CH2)4Si]
Authors: Dużak Tomasz , Kinzhybalo Vasyl , Ślepokura Katarzyna , Olijnyk Volodymyr
Published: April 2009

By alternating‐current electrochemical technique, starting from CuCl2·2H2O and tetraallylsilane (TAS), crystals of the π complex [Cu5Cl5(CH2–CH=CH2)4Si] (I) were obtained, FTIR characterized and structurally investigated. The structure of I is monoclinic, space group P21/n, a = 12.292(3), b = 12.083(3), c = 13.356(3) Å, β = 90.19(3)°, V = 1983.7(9) Å3 [at 100(2) K], Z = 4; R1 = 0.0379, wR2 = 0.1040 for 3583 reflections. The TAS molecule behaves as a tetradentate cross‐bridged ligand linking four (Cu5Cl5)∞ fragments through the C=C bonds. The influence of the inorganic part and ligand symmetries combined with their conformational abilities on the overall crystal symmetry is discussed.