bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal partial hedging of options with small transaction costs
Authors: Whalley A. Elizabeth
Published: January 2011

This study uses asymptotic analysis to derive optimal hedging strategies for option portfolios hedged using an imperfectly correlated hedging asset with small fixed and/or proportional transaction costs, obtaining explicit formulae in special cases. This is of use when it is impractical to hedge using the underlying asset itself. The hedging strategy holds a position in the hedging asset whose value lies between two bounds, which are independent of the hedging asset's current value. For low absolute correlation between hedging and hedged assets, highly risk‐averse investors and large portfolios, hedging strategies and option values differ significantly from their perfect market equivalents. © 2011 Wiley Periodicals, Inc. Jrl Fut Mark 31:855–897, 2011
Chromosome‐specific segmentation revealed by structural analysis of individually isolated chromosomes
Authors: Kitada Kunio , Taima Akira , Ogasawara Kiyomoto , Metsugi Shouichi , Aikawa Satoko
Published: January 2011

Analysis of structural rearrangements at the individual chromosomal level is still technologically challenging. Here we optimized a chromosome isolation method using fluorescent marker‐assisted laser‐capture and laser‐beam microdissection and applied it to structural analysis of two aberrant chromosomes found in a lung cancer cell line. A high‐density array‐comparative genomic hybridization (array‐CGH) analysis of DNA samples prepared from each of the chromosomes revealed that these two chromosomes contained 296 and 263 segments, respectively, ranging from 1.5 kb to 784.3 kb in size, derived from different portions of chromosome 8. Among these segments, 242 were common in both aberrant chromosomes, but 75 were found to be chromosome‐specific. Sequences of 263 junction sites connecting the ends of segments were determined using a PCR/Sanger‐sequencing procedure. Overlapping microhomologies were found at 169 junction sites. Junction partners came from various portions of chromosome 8 and no biased pattern in the positional distribution of junction partners was detected. These structural characteristics suggested the occurrence of random fragmentation of the entire chromosome 8 followed by random rejoining of these fragments. Based on that, we proposed a model to explain how these aberrant chromosomes are formed. Through these structural analyses, it was demonstrated that the optimized chromosome isolation method described here can provide high‐quality chromosomal DNA for high resolution array‐CGH analysis and probably for massively parallel sequencing analysis. © 2011 Wiley‐Liss, Inc.
Reactions of nitroxides, part XI: O‐Aryl phenylselenophosphonates bearing a nitroxyl moiety
Authors: Huras Bogumiła , Zakrzewski Jerzy , Krawczyk Maria
Published: January 2011

O‐Aryl phenylselenophosphonates bearing a nitroxyl moiety were synthesized in the presence of pyridine in diethyl ether from 4‐hydroxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl, and either phenyldichlorophosphine and elemental selenium in 9–35% yield or phenyldichlorophosphine selenide in 36–62% yield. O,O‐Diaryl phenylselenophosphonates and O,O‐bis(2,2,6,6‐tetramethyl‐1‐oxyl‐4‐piperidyl)phenylselenophosphonates were obtained as by‐products. O,O‐Diaryl phenylselenophosphonates were obtained from phenyldichlorophosphine selenide and 2 mol of phenols in 55–86% yield. Antifungal activity of some synthesized selenophosphonates was found. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:137–147, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20667
Visualization of water transport in GDL and flow channel of PEMFC
Authors: Ma Yue , Jia Li , Zhang Zhuqian , Wang Xia
Published: January 2011

Liquid water penetrating the gas diffusion layer (GDL) of a proton exchange membrane fuel cell (PEMFC) was studied. The gas diffuse layer (GDL) has a great impact on PEMFC's performanc3e, and is an important component of a PEMFC. An ex‐situ test was conducted on a transparent test cell to visualize the water droplet formation and detachment on the surface of different types of GDLs through a CCD camera. The breakthrough pressure, at which the liquid water penetrates the GDL and starts to form a droplet, was measured. The breakthrough pressure was found to be different for GDLs with different porosities and thicknesses. The equilibrium pressure, which is defined as the minimum pressure required for maintaining a constant flow through the GDL, was also recorded. The equilibrium pressure was found to be much lower than the breakthrough pressure for the same type of GDL. Also the drain performance using three kinds of different bipolar plates were compared in this paper. According to the result of experiment, the average diameters of porous GDLs were found determining the penetrating pressure. Serpentine flow channel proved the best pattern for drainage. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/htj.20330
Numerical simulation on freezing phase change heat transfer in cryosurgery with two cryoprobes
Authors: Zhao Fang , Chen Zhenqian , Shi Mingheng
Published: January 2011

A mathematical model for phase change heat transfer in biological tissue (including tumor and normal tissue) embedded with two cryoprobes was established. In this model, the vascular architecture was described as a tree‐like branched fractal network, and the effective thermal conductivity and flow rate of blood were presented based on this fractal structure. Occurrence of three regions including frozen, phase‐changing, and unfrozen regions in biological tissue during the freezing process was also considered. The numerical studies on temperature distribution and ice crystal growth process in biological tissue embedded with two cryoprobes were performed. The results showed that the growth rate of ice crystal is more rapid in the initial freezing stage and becomes slower later. So it is unreasonable to prolong freezing time merely without other assisting measures for enlarging the freezing region in the late freezing stage. Furthermore, the placement distance of the two cryoprobes plays a significant role in the growth of ice crystal in the initial freezing stage, and the influence of different distances between two probes on ice crystal growth becomes less profound with an increasing of freezing time. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/htj.20332
Curbing domestic violence: instantiating C–K theory with formal concept analysis and emergent self‐organizing maps
Authors: Poelmans Jonas , Elzinga Paul , Viaene Stijn , Dedene Guido
Published: January 2011

We propose a human‐centred process for knowledge discovery from unstructured text that makes use of formal concept analysis and emergent self‐organizing maps. The knowledge discovery process is conceptualized and interpreted as successive iterations through the concept–knowledge (C–K) theory design square. To illustrate its effectiveness, we report on a real‐life case study of using the process at the Amsterdam–Amstelland police in the Netherlands aimed at distilling concepts to identify domestic violence from the unstructured text in actual police reports. The case study allows us to show how the process was not only able to uncover the nature of a phenomenon such as domestic violence, but also enabled analysts to identify many types of anomaly in the practice of policing. We will illustrate how the insights obtained from this exercise resulted in major improvements in the management of domestic violence cases. Copyright © 2010 John Wiley & Sons, Ltd.
Polysorbate cationic synthetic vesicle for gene delivery
Authors: Huang Yongzhuo , Rao Yuefeng , Chen Jinliang , Yang Victor C. , Liang Wenquan
Published: January 2011

Synthetic nonionic surfactant vesicles (niosomes) are a colloidal system with closed bilayer structures, displaying distinct advantages in stability and cost compared with liposomes. In this article, polysorbate cationic niosomes (PCNs) were developed as gene carriers. The PCNs comprised nonionic surfactants (i.e., polysorbates) and a cationic cholesterol, and were synthesized using a film hydration method. The niosomes thus prepared possessed a regular morphology, and a particle size of 100 ∼ 200 nm, and a zeta potential of +30 ∼ 45 mV. The PCNs showed great physical stability over the course of 4 weeks at room temperature. The binding capacity of PCNs toward oligodeoxynucleotides (ODN) was assessed by a gel retardation approach, which demonstrated that the ionic complexes were formed when ± charge ratio reached to 4 or greater. Gene transfer study showed that the PCNs exhibited a high efficiency in mediating cellular uptake and transferred DNA expression. Based on these findings, PCNs may offer the potential to function as an effective gene delivery system. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
The significance of repetitive hair‐pulling behaviors in eating disorders
Authors: Zucker Nancy , Von Holle Ann , Thornton Laura M. , Strober Michael , Plotnicov Kathy , Klump Kelly L. , Brandt Harry , Crawford Steve , Crow Scott , Fichter Manfred M. , Halmi Katherine A. , Johnson Craig , Kaplan Allan S. , Keel Pamela , LaVia Maria , Mitchell James E. , Rotondo Alessandro , Woodside D. Blake , Berrettini Wade H. , Kaye Walter H. , Bulik Cynthia M.
Published: January 2011

We studied the relation between intrusive and repetitive hair pulling, the defining feature of trichotillomania, and compulsive and impulsive features in 1,453 individuals with anorexia nervosa and bulimia nervosa. We conducted a series of regression models examining the relative influence of compulsive features associated with obsessive‐compulsive disorder, compulsive features associated with eating disorders, trait features related to harm avoidance, perfectionism, and novelty seeking, and self harm. A final model with a reduced sample (n = 928) examined the additional contribution of impulsive attributes. One of 20 individuals endorsed hair pulling. Evidence of a positive association with endorsement of compulsive behavior of the obsessive‐compulsive spectrum emerged. Hair pulling may be more consonant with ritualistic compulsions than impulsive urges in those with eating disorders. © 2011; Wiley Periodicals, Inc. J Clin Psychol 00:1–13, 2011.
Sorbent coatings for solid‐phase microextraction based on mixtures of polymeric ionic liquids
Authors: Graham Christa M. , Meng Yunjing , Ho Tien , Anderson Jared L.
Published: January 2011

Four polymeric ionic liquids based on two different cations, poly(1‐vinyl‐3‐hexylimidazolium) and poly(1‐vinyl‐3‐hexadecylimidazolium), combined with two different anions, bis[(trifluoromethyl)sulfonyl]imide (NTf) and chloride (Cl−), were combined in various weight percentages and used as sorbent coatings for solid‐phase microextraction gas chromatography (SPME‐GC). The selectivity of the fiber coatings for 12 test analytes was examined. The extraction efficiency of n‐alcohols increased with an increase in the weight percentage of chloride ion in the sorbent coating. The ability to tune the interactions between the coating material and the analytes was exploited and resulted in distinct changes in the limits of detection for hydrogen‐bonding analytes with varying chloride ion content in the sorbent coating.
Preparation of novel polydimethylsiloxane solid‐phase microextraction film and its application in liquid sample pretreatment
Authors: Wei Fang , Zhang Fang‐Fang , Liao Hui , Dong Xu‐Yan , Li Yan‐Hua , Chen Hong
Published: January 2011

In this paper, an extraction approach based on the use of a novel polydimethylsiloxane (PDMS) film as the extraction medium was described. Two kinds of PDMS films with smooth surface and frosted surface were prepared and were practically evaluated for extraction. A model analytical problem, the determination of organochlorine pesticides in water samples, was selected for practical evaluation of the film extraction procedure by direct extraction and solvent desorption, followed by gas chromatography (GC) analysis with electron capture detection (ECD). The main variables affecting the extraction process such as the extraction time, the extraction temperature, the elution conditions, etc. were studied. The method was characterized on the basis of its linearity, precision, and limits of detection. The novel approach was sensitive and precise enough for the detection of the target analytes in the low nanogram per liter range using 5 mL of sample. In fact, limits of detection ranging from 0.77 to 10.25 ng/L were obtained. Compared with the solid‐phase microextraction (SPME) fiber, the robust extraction film has a large extraction capacity, low cost of preparation. Besides, owing to the simplicity of the extraction procedures, in‐site sample preparation for environmental monitor may be realized.
Prediction of pesticides chromatographic lipophilicity from the computational molecular descriptors
Authors: Casoni Dorina , Petre Jana , David Victor , Sârbu Costel
Published: January 2011

Quantitative structure–property relationship models were developed for the prediction of pesticides and some PAH compounds lipophilicity based on a wide set of computational molecular descriptors and a set of experimental chromatographic data. The chromatographic lipophilicity of pesticides has been evaluated by high‐performance liquid chromatography (HPLC) using different chemically bonded (C18, C8, CN and Phenyl HPLC columns) stationary phases and two different organic modifiers (methanol and acetonitrile, respectively) in the mobile phase composition. Through a systematic study, by using the classic multivariate analysis, several quantitative structure–property/lipophilicity multi‐dimensional models were established. Multiple linear regression and genetic algorithm for the variable subset selection were used. The internal and external statistical evaluation procedures revealed some appropriate models for the chromatographic lipophilicity prediction of pesticides. Moreover, the statistical parameters of regression and those obtained by applying t‐test for the intercept (a0) and for the slope (a1) in order to evaluate relationship between experimental and predicted octanol–water partition coefficients in case of the test set compounds, revealed two statistically valid models that can be successfully used in lipophilicity prediction of pesticides.
Qualitative and quantitative determination of nine main active constituents in Pulsatilla cernua by high‐performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry
Authors: Xu Huijun , Shi Xiaowei , Ji Xiang , Du Yingfeng , Zhu Hong , Zhang Lantong
Published: January 2011

A novel qualitative and quantitative method using high‐performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC‐ESI‐MS/MS) was developed for simultaneous determination of the nine major active constituents in Pulsatilla cernua (Thunb.) Bercht. et Opiz., namely anemoside A3 (1), anemoside B4 (2), 23‐hydroxybetulinic acid (3), cirenshenoside S (4), pulsatilloside B (5), pulsatilloside C (6), oleanolic acid (7), ajugasterone C (8) and β‐ecdysterone (9), respectively. A Sapphire C18 column (250 mm×4.6 mm, 5 μm) and gradient elution were used during the analysis. The identification and quantification of the analytes were achieved on a hybrid quadrupole linear ion trap mass spectrometer. Multiple‐reaction monitoring (MRM) scanning was employed for quantification with switching electrospray ion source polarity between positive and negative modes in a single run. All calibration curves showed good linearity (r2>0.9948) within the test ranges. The intra and interday variations for nine analytes were less than 3.95 and 3.78%, respectively. The developed method was successfully applied to determine the investigated compounds in 15 batches of natural and cultured samples of P. cernua. The results indicated that the method was simple, rapid, specific and reliable, which is helpful to comprehensive evaluation of quality of P. cernua.
Retention prediction in reversed‐phase liquid chromatography systems with methanol/water mobile phases containing different alkanols as additives
Authors: Pappa‐Louisi Adriani , Agrafiotou Panagiota , Fasoula Stella
Published: January 2011

In an effort to gain enhancement of selectivity in reversed‐phase liquid chromatography, retention was tuned in this study by introducing short and medium straight‐chained‐length alkanol additives (methanol (MeOH), ethanol, 1‐propanol, 1‐butanol, 1‐pentanol, 1‐hexanol or 1‐heptanol) at low concentrations in mobile phases containing MeOH as the main organic solvent. A six‐parameter retention model considering simultaneously the contents of the main organic modifier and of the alcohol additive as well as of the number of alkyl chain of additive was developed by a direct combination of equations expressing separately a linear dependence of the retention upon each of these factors. The effectiveness of the above model was tested in the retention prediction of a mixture of six alkylbenzenes under isocratic conditions with mobile phases containing as an additive any member of the homologues series of alkanols (with 1–7 carbon atoms) at different low concentrations in a wide range of MeOH–water mixtures. The prediction was excellent in all cases even when the alkanol additives used in experiments for the fitting procedure are different than those used in chromatographic runs done for testing the prediction ability of the proposed model.
Preparative separation of quaternary ammonium alkaloids from Corydalis yanhusuo W. T. Wang by pH‐zone‐refining counter‐current chromatography
Authors: Yu Qing , Tong Shengqiang , Yan Jizhong , Hong Chaoqun , Zhai Wenfeng , Li Yaqin
Published: January 2011

The optimal extraction condition for extracting quaternary ammonium alkaloid dehydrocorydaline from Corydalis yanhusuo W. T. Wang was investigated using orthogonal experimental design. pH‐zone‐refining counter‐current chromatography (CCC) with normal phase elution was successfully applied to preparative separation of alkaloids from the crude extract of Corydalis yanhusuo. The separation was performed with a biphasic solvent system composed of chloroform (CHCl3)–methanol (MeOH)–water (2:1:1, v/v), in which the lower organic phase containing 10 mM of triethylamine was used as the mobile phase, while the upper aqueous phase containing 10 mM of hydrochloric acid was used as the stationary phase. The separation mechanism of quaternary ammonium alkaloids using pH‐zone‐refining CCC was discussed in comparison with standard high‐speed CCC. In the present study, the separation of 1.200 g of crude sample yielded 129 mg of dehydrocorydaline and 12 mg of palmatine at a high purity of 94 and 92%, respectively. Recovery for dehydrocorydaline and palmatine was 85 and 86%, respectively.
Revisiting MacCannell's site sacralization theory as an analytical tool: Historic prophetstown as a case study
Authors: Forristal Linda Joyce , Marsh Dawn Gay , Lehto Xinran Y.
Published: January 2011

Historic Prophetstown in Battle Ground, Indiana is intrinsically connected to a pivotal event in Native American and United States military history. While it appears to have all the necessary elements to become a successful tourism attraction, it consistently teeters on the verge of insolvency. Applying sociologist Dean MacCannell's (1976) five‐stage site sacralization theory as an analytical lens to investigate the site revealed that it has never successfully moved beyond MacCannell's first stage (i.e. naming), which may be a key factor contributing to low visitation and poor economic performance. This suggests that MacCannell's theory can offer unique insights into site development. Copyright © 2010 John Wiley & Sons, Ltd.
Polymerisation of Norbornene Catalysed by Highly Active Tetradentate Chelated α‐Diimine Nickel Complexes
Authors: Li Lidong , Gomes Pedro T. , Lemos M. Amélia N. D. A. , Lemos Francisco , Fan Zhiqiang
Published: January 2011

A series of three recently synthesised tetradentate chelated α‐diimine nickel complexes of the type [NiBr2(Ar‐BIAN)] (where Ar = 2‐(1‐R‐1H‐1,2,3‐triazol‐4‐yl)phenyl; R = benzyl 1, 1‐phenylethyl 2, phenyl 3) are used as precatalysts for the polymerisation of norbornene. When activated with MAO, 1–3 are highly active catalysts for the production of high molecular weight polynorbornene (e.g., 1.39 × 107 g PNB mol Ni−1 · h−1). The catalytic activity and polymer molecular weight increase markedly with the initial concentration of norbornene, but both parameters decrease with the reaction time. The characterisation of the polynorbornenes by NMR, GPC/SEC, X‐ray diffraction, and DSC/TGA leads to the assignment of a structure typical of a polynorbornene originated by a coordination vinyl addition mechanism.

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Use of Reactive and Functional Hydrophobes (Hydrophobins) in the Miniemulsion Polymerization of Styrene and Methyl Methacrylate
Authors: Agarwal Seema , Grabe Norman
Published: January 2011

The successful use of multitasking polycaprolactone‐based hydrophobins for miniemulsion polymerization of model monomers like styrene and methyl methacrylate is demonstrated. These hydrophobins were synthesized in two steps – the synthesis of polyester diol (i.e., polycaprolactone diol) followed by polycondensation with an equimolar amount of azobis(cyanopentanoic acid dichloride). The hydrophobin, besides acting as a hydrophobe and initiator for the miniemulsion polymerization, also provided functionality; in this case degradability to the miniemulsion. An optimum ratio of hydrophobin to monomer was required for making stable dispersions of a small size (average diameter around 100 nm) with relatively high solid content (around 22%).

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Association of a Cylindrical Polyelectrolyte Brush with Tetravalent Counterions
Authors: Ruthard Christian , Maskos Michael , Yildiz Hakan , Gröhn Franziska
Published: January 2011

Cylindrical poly(styrene sulfonate) brushes were combined with a tetravalent double‐DABCO based counterion. With increasing addition of counterion, hydrodynamic radius and radius of gyration decrease and AFM reveals a conformation change from wormlike to curled structures. Rg/Rh changes from 1.3 to 0.9. Above charge stoichiometry, brushes become interconnected into finite size assemblies, which are stable in aqueous solution for charge ratios (ratio of the molar concentration of charged counterion groups to the molar concentration of charged monomer units of the polymer brush) 1 < l < 1.2. They are compact and consist of the brushes in curled (bent) conformation, which is in difference to network‐like aggregates from cylindrical poly(styrene sulfonate) brushes with tetravalent porphyrin counterions (Gröhn et al. Macromolecules 2009) and to a wormlike—bent conformation—helix transition found for another brush counterion system (Müller et al. Soft Matter 2009).

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Tailored Polymer Microstructures Prepared by Atom Transfer Radical Copolymerization of Styrene and N‐substituted Maleimides
Authors: Lutz Jean‐François , Schmidt Bernhard V. K .J. , Pfeifer Sebastian
Published: January 2011

In the present Feature Article, a kinetic strategy for controlling the microstructure of synthetic polymer chains prepared via a radical chain‐growth polymerization process is presented. This approach was recently developed in our laboratory and relies on the controlled kinetic addition of ultrareactive N‐substituted maleimides during the atom transfer radical polymerization of styrene. This method is experimentally straightforward and can be applied to a broad library of functional N‐substituted maleimides. Thus, this platform allows synthesis of unprecedented polymer materials such as 1D macromolecular arrays. The basic kinetic requirements, the experimental conditions, and the synthetic scope of this approach are discussed in details herein.

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Functionalization of Hydrogels Based on N‐Isopropyl‐acrylamide and Cationic Surfactant Monomers upon Electrostatic Self‐Assembly
Authors: Friedrich Tatjana , Trinker Anna , Tieke Bernd
Published: January 2011

Summary: Positively charged copolymer hydrogels based on N‐isopropyl‐acrylamide (NiPAAm) and a cationic surfactant monomer (surfmer) were functionalized upon electrostatic self‐assembly of functional organic or inorganic complex counterions in the gel. As cationic surfmers 11‐acryloylundecyltrimethylammonium bromide (AUTMAB) or 11‐methacryloyl‐undecyltrimethylammonium bromide (MUTMAB) were used. The hydrogels were prepared from a micellar aqueous solution of the surfmer and NiPAAm either upon 60Co‐gamma irradiation, or upon chemical cross‐linking using methylenebisacrylamide as cross‐linker and 1,4‐diaminobutane as accelerator. Electrostatic self‐assembly was facilitated utilizing the thermoresponsive swelling and shrinking of the hydrogel. Several examples of gel functionalization are described such as in‐situ preparation of Prussian Blue and Pd0 nanoparticles, and induction of fluorescent properties. The catalytic activity of the palladium‐containing gel was studied by investigating the reduction of 4‐nitrophenol (4‐NP) with sodium borohydride as a model reaction. Fluorescent gels can be prepared upon exchange of bromide against 1‐pyrenesulfonate ions in the gel.
3D Stereolithography by Using Two‐Photon Photopolymerization
Authors: Kim Ran Hee , Lee Kwang‐Sup
Published: January 2011

Summary: This article describes the development and evolution of two‐photon lithography of 3‐dimensional (3D) polymeric structures through two‐photon photopolymerization (TPP) and the materials used to facilitate the same. The first part elaborates on the advantages of TPP over conventional lithographic techniques used in the fabrication of 3D microelectromechanical systems (MEMS). The second part introduces the preparation of highly efficient organic two‐photon absorbing materials based on the centro‐symmetric π‐conjugated system and their performance as sensitizers in two‐photon polymerization.
Small‐Molecule Diffusion in Semicrystalline Polymers as Revealed by Experimental and Simulation Studies
Authors: Nilsson Fritjof , Hedenqvist Mikael S. , Gedde Ulf W.
Published: January 2011

Summary: Diffusion of n‐hexane in poly(ethylene‐co‐1‐hexene)s with 15–75 wt.% crystallinity was studied by desorption experiments analyzing data using the Fickian equations with a concentration dependent diffusivity. The effect of the impenetrable crystalline phase on the penetrant diffusivity (D) is described by D = Da/(τβ), where Da is the diffusivity of the amorphous polymer, τ is the geometrical impedance factor and β is a factor describing the constraining effect of the crystals on the non‐crystalline phase. For a polymer with 75 wt.% crystallinity, τβ varied markedly with penetrant concentration (v1a) in the penetrable phase: 1000 (v1a = 0) and 10 (v1a = 0.15). This penetrant‐uptake had no effect on the gross crystal morphology, i.e. β must be strongly dependent on v1a. Samples saturated in n‐hexane exhibited a penetrant‐induced loosening of the interfacial structure, as revealed by an increase in crystal density that require an increased mobility in the interfacial component and by a decrease in the intensity of the asymmetric X‐ray scattering associated with the interfacial component. The geometrical impedance factor has been modelled by mimicking spherulite growth and τ was obtained as the ratio of the diffusivities of the fully amorphous and semicrystalline systems. The maximum τ obtained from these simulations is ca. ten, which suggests that β in the systems with v1a = 0.15 takes values close to unity. The simulations showed that the geometrical impedance factor is insensitive to the ratio of the crystal width and the crystal thickness. A free path length scaling parameter characteristic of the amorphous phase correlated with τ.
Synthesis and Properties of Dendronized Chitosan
Authors: Aldana Ana Agustina , Martinelli Marisa , Strumia Miriam
Published: January 2011

Summary: Chitosan films and microspheres were prepared and their surfaces were functionalized with first generation dendritic molecules. The films were modified by Weisocyanate dendron, while Behera's and bis Behera's amine dendrons were used to modify the microspheres. Prior to dendronization films were prepared by blending chitosan with 18% of polyvinyl pyrrolidone (PVP), and casting the resulting mixture. The degree of dendronization reached was 28%. The microspheres were prepared by coacervation/precipitation, after which the surfaces were activated with either epychlorohydrine (ECH) or 1,4‐butanediol diglycidyl ether (BDGE). The oxirane groups were utilized to form covalent bonds between chitosan and dendrons. The degree of dendronization yielded with Behera's amine was 60% for both activating agents. When bis Behera's amine was used, the dendronization reached values of 15 and 21% when ECH or BDGE were used, respectively. The dendronized products were characterized through spectroscopic and microscopic studies and by determination of swelling indexes. Only one of the surfaces was dendronized in every film, which therefore presented a hydrophobic and a hydrophilic surface. Since these films maintain the properties of chitosan, they offer interesting potential as dressings for exuding wounds. The different surfaces make the microspheres potentially applicable as carriers for delivery and controlled release of drugs.
Separation of Poly(propylene) Samples According to Tacticity Using a Hypercarb Column
Authors: Macko Tibor , Cutillo Francesco , Busico Vincenzo , Brüll Robert
Published: January 2011

Summary: Samples of polypropylene having different stereoregularities, i.e., differing in the isotactic or syndiotactic stereosequence distribution, were separated by means of high‐temperature gradient adsorption liquid chromatography. The porous graphite was used as stationary phase in the column packing (Hypercarb®). Predominantly isotactic samples eluted in 1‐decanol, while predominantly syndiotactic samples eluted in a binary gradient composed of 1‐decanol and 1,2,4‐trichlorobenzene. Their elution volumes increased with the average content of the syndiotactic units (racemo dyads mole fraction as determined with the NMR spectroscopy) in the samples. Thus these chromatographic separations represent a new method for the analysis and characterization of stereoregular polyolefins. It requires substantially less time and solvents than the commonly used methods.
Dynamic Viscosity of PEG:PEG‐ran‐PPG Blends through Stress Relaxation
Authors: Das Ashok K. , Hsu Di‐Yao , Hong Po‐Da
Published: January 2011

Densities and viscosities of a series of blends of poly(ethylene glycol) (PEG) and poly(ethylene glycol‐ran‐propylene glycol) (PEG‐ran‐PPG) were measured at a temperature above the melting point. The density and viscosity data were fitted with analytical functions involving the volume fraction of PEG,ϕPEG. Stress relaxation curves for the pure components and blends were obtained through Monte Carlo (MC) simulations. A typical stress relaxation curve exhibits a fast mode that represents energetic‐interactions‐driven motion and a slow mode that originates from the entropy‐driven motion. Flory–Huggins interaction parameters (χ) for the blends are much smaller than the critical values (χcritical). The calculation ofχandχcriticalprovides important clues for polymer blend processing.

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Oil supply projection techniques: Past developments and future requirements
Authors: Bruce Alistair
Published: January 2011

This paper presents a critical assessment of the development of economic models of oil supply projection over the last two decades. The survey illustrates the fact that although most models have stressed the significance of the economic variables in the supply function, few attempts have been made to incorporate technology as a variable. Although such an approach can be justified under certain special circumstances, it is considered unsuitable as a supply forecaster in the increasingly numerous marginal fields where operations approach the technology frontier. In this connection, the latter part of the paper discusses the possibility of and problems associated with incorporating technology as a variable in the projection of supply.
Se‐methylselenocysteine inhibits lipopolysaccharide‐induced NF‐κB activation and iNOS induction in RAW 264.7 murine macrophages
Authors: Pan Min‐Hsiung , Hong Huei‐Mei , Lin Chih‐Li , Jhang Ai‐Zhi , Tsai Jie‐Heng , Badmaev Vladimir , Nagabhushanam Kalyanam , Ho Chi‐Tang , Chen Wei‐Jen
Published: January 2011

Scope: Se‐methyl‐L‐selenocysteine (MSC), a naturally occurring organoselenium compound, has shown cancer chemopreventive activity against several types of cancer. Herein, the effect of MSC on the inflammatory response in lipopolysaccharide (LPS)‐activated murine RAW 264.7 macrophage cells was investigated.

Methods and results: The present results demonstrated that MSC markedly inhibited LPS‐induced production of NO in a dose‐dependent pattern with decreased mRNA and protein levels of inducible nitric oxide synthase (iNOS). MSC also reduced nuclear translocation of p65 and p50 subunits of nuclear factor‐κB (NF‐κB), a critical transcription factor necessary for iNOS expression, accompanied with downregulation of LPS‐triggered NF‐κB‐dependent gene expression evaluating by a luciferase reporter. Inhibition of nuclear translocation by MSC might result from the prevention of the inhibitor of NF‐κB from phosphorylation and consequent degradation via suppression inhibition of phosphorylation of IκB kinase α/β. Exploring the action mechanism involved, MSC can reduce the phosphorylation/activation of mitogen‐activated protein kinases (MAPKs) related to NF‐κB activation induced by LPS, including p38 MAPK and c‐Jun N‐terminal kinase in RAW 264.7 cells.

Conclusion: MSC might contribute to the potent anti‐inflammatory effect in LPS‐activated RAW 264.7 cells via downregulation of NF‐κB activation and iNOS expression, suggesting that MSC may be considered as a therapeutic candidate for chronic inflammatory diseases.
BIRD‐J‐resolved HMBC and BIRD‐high‐resolution HMBC pulse sequences for measuring heteronuclear long‐range coupling constants and proton–proton spin coupling constants in complicated spin systems
Authors: Furihata Kazuo , Tashiro Mitsuru , Seto Haruo
Published: January 2011

Efficient pulse sequences for measuring long‐range CH coupling constants (JCH) and proton‐proton spin coupling constants (JHH), named BIRD‐J‐resolved HMBC and BIRD‐high‐resolution HMBC, respectively, have been developed. In spin systems possessing a secondary methyl group positioned between protonated carbons (e.g.CH2CH(CH3)CH2), the methine proton splits in a complicated fashion, resulting in difficulty in the determination of its spin coupling constants. For easy and accurate measurements of the long‐range JCH and JHH in such a spin system, the BIRD pulse [90°x(H)− 180°x (H/C)− 90° (−x)(H)] or [90°x(H)− 180°x(H/C)− 90° (−x)(H)180°x(C)] is incorporated into the J‐resolved portion of the pulse sequence. As a result, the above secondary methyl group can be selectively decoupled, providing simplified cross‐peak patterns, which are suitable for the accurate measurements of the long‐range JCH and JHH. Copyright © 2010 John Wiley & Sons, Ltd.
An EPR analysis of β‐dimerization in α‐blocked pyrroles in oxidant conditions
Authors: Julià Luis , Rius Jordi , Torrelles Xavier
Published: January 2011

Electron paramagnetic resonance (EPR) analysis of neutral and acidic solutions of 2,5‐dimethyl‐1‐phenylpyrrol (1) and meta‐, para‐, and ortho‐bis(2,5‐dimethylpyrrol‐1‐yl)benzenes (4–6) in the presence of Tl(III) trifluoroacetate as oxidant reveals the poor stability of their generated monomeric radical cations which dimerize through C(β)C(β) bond formation. EPR spectra of the monomeric radical cations 4•+, 5•+, and 6•+ coincide with that of 1•+, suggesting that the unpaired electron in these charged species is confined in one of the pyrrolic rings. The very twisted angles between pyrrolic and phenyl planes due to steric hindrance in the X‐ray analysis of the molecular structure of 4 confirm the absence of extended conjugation in the π‐system. Copyright © 2011 John Wiley & Sons, Ltd.
Polymer‐bound 4‐methylcoumarin/1‐heptanoyl‐5‐fluorouracil photodimers: NMR elucidation of dimer structure
Authors: Sinkel Carsten , Schwarzer Martin C. , Frenking Gernot , Greiner Andreas , Agarwal Seema
Published: January 2011

Heterodimers based on the polymer‐bound chromophore 4‐methylcoumarin and the prodrug 1‐heptanoyl‐5‐fluorouracil, synthesized by photochemical [2 + 2]‐cycloaddition are promising photoresponsive drug depots. Drug release experiments are one possibility to deliver proof of a successful reversible drug immobilization, whereas NMR spectroscopy is a potent tool for further structural characterization of these polymer‐bound heterodimers. In case of the random copolymer poly(methyl methacrylate‐co‐7‐(2′‐methacryloyloxyethoxy)‐4‐methylcoumarin) three dimers have been identified of which the syn head‐to‐tail was the predominant one. In contrast, only the syn head‐to‐head dimer was formed in reasonable yield when the 4‐methylcoumarin monofunctionalized pMMA was used as the base polymer. 1D and 2D NMR spectroscopic techniques combined with some theoretical calculations helped in successfully closing one major gap concerning polymer bound 4‐methylcoumarin/1‐heptanoyl‐5‐fluorouracil heterodimers that are of potential use in photoresponsive drug delivery devices. Copyright © 2011 John Wiley & Sons, Ltd.
Perinatal outcome of prenatally diagnosed congenital talipes equinovarus
Authors: Sharma Rowena , Stone Stephanie , Alzouebi Aisha , Hamoda Haitham , Kumar Sailesh
Published: January 2011

Objective

The purpose of this study was to investigate the perinatal outcome of prenatally diagnosed congenital talipes equinovarus.

Methods

This was a retrospective observational study of all cases of prenatally diagnosed congenital talipes equinovarus referred to a major tertiary fetal medicine unit. Cases were identified from the fetal medicine and obstetric databases and pregnancy details and delivery outcome data obtained. Details of termination of pregnancy, number of patients undergoing karyotyping as well as details of prenatal classification of severity were recorded.

Results

A total of 174 cases were identified. Of these, outcome data was available for 88.5% (154/174) of the pregnancies. Eighty three (47.7%) of cases were isolated and 91 cases (52.3%) were associated with additional abnormalities. There was a significant difference in birth weights between the two cohorts. Bilateral abnormality tended to be more severe. A high caesarean section rate was noted overall and a high preterm delivery rate seen in the isolated group.

Conclusion

This study is important because it provides contemporary data that can be used to counsel women prenatally. In particular, the raised risk of preterm delivery and caesarean section as well as the increased severity of the condition when both feet are affected should be discussed. The poor perinatal outcome when additional anomalies are present and the increased risk of aneuploidy are also important factors. Copyright © 2011 John Wiley & Sons, Ltd.
Uncertainty of the spectral mismatch correction factor in STC measurements on photovoltaic devices
Authors: Hohl‐Ebinger Jochen , Warta Wilhelm
Published: January 2011

Valuation of photovoltaic devices depends strongly on the measured power output of the device. This quantity is usually determined under artificial sunlight in production line measurement systems or industrial or research test labs. A practical calibration chain is realized essentially with measurements at solar simulators. The measurement conditions are defined in the IEC 60904 series of standards. An important part of the standard testing conditions is the definition of a specific spectral distribution of the sunlight (AM1.5 global). The inevitable deviations of the spectrum of artificial light sources from the standard spectrum have to be taken into account by a spectral mismatch factor. The uncertainty of this crucial correction is spectrally dependent, in most cases unknown and complex and inconvenient to evaluate. In this article a randomizing method is proposed which allows one to calculate the uncertainty of the mismatch factor from the uncertainties of the input parameters determined with high spectral resolution. Based on a range of different spectral responses of solar cells on the one hand and variations of the solar simulator spectral distribution on the other, we are able to generalize the results to a broad set of measurement configurations. A sensitivity analysis reveals the crucial wavelength regions and thus allows the systematic optimization of simulator spectra and selection of reference cells. Copyright © 2010 John Wiley & Sons, Ltd.
Proteomic profiling of cerebrospinal fluid identifies prostaglandin D2 synthase as a putative biomarker for pediatric medulloblastoma: A pediatric brain tumor consortium study
Authors: Rajagopal Meena U. , Hathout Yetrib , MacDonald Tobey J. , Kieran Mark W. , Gururangan Sri , Blaney Susan M. , Phillips Peter , Packer Roger , Gordish‐Dressman Heather , Rood Brian R.
Published: January 2011

The aims of this study were to demonstrate the feasibility of centrally collecting and processing high‐quality cerebrospinal fluid (CSF) samples for proteomic studies within a multi‐center consortium and to identify putative biomarkers for medulloblastoma in CSF. We used 2‐DE to investigate the CSF proteome from 33 children with medulloblastoma and compared it against the CSF proteome from 25 age‐matched controls. Protein spots were subsequently identified by a combination of in‐gel tryptic digestion and MALDI‐TOF TOF MS analysis. On average, 160 protein spots were detected by 2‐DE and 76 protein spots corresponding to 25 unique proteins were identified using MALDI‐TOF. Levels of prostaglandin D2 synthase (PGD2S) were found to be six‐fold decreased in the tumor samples versus control samples (p<0.00001). These data were further validated using ELISA. Close examination of PGD2S spots revealed the presence of complex sialylated carbohydrates at residues Asn78 and Asn87. Total PGD2S levels are reduced six‐fold in the CSF of children with medulloblastoma most likely representing a host response to the presence of the tumor. In addition, our results demonstrate the feasibility of performing proteomic studies on CSF samples collected from patients at multiple institutions within the consortium setting.
Proteome analysis of Fusarium head blight in grains of naked barley (Hordeum vulgare subsp. nudum)
Authors: Eggert Kai , Pawelzik Elke
Published: January 2011

The effect of artificial Fusarium graminearum and F. culmorum infection at the level of the proteome on grains of naked barley (Hordeum vulgare subsp. nudum) was investigated in comparison to naturally infected samples. Fusarium infection in barley led to numerous host‐specific biochemical responses. NEPHGE 2‐D PAGE and MS were used to identify proteins that were differentially expressed in response to fungal infection and growing location of the plants. Moreover, the mycotoxin concentration of the grains was evaluated to characterize the infection degree. Inoculation of naked barley with Fusarium led to grain deoxynivalenol concentrations of up to 1.2 mg/kg. The carbon and nitrogen grain concentrations were not significantly changed after fungal infection, but differed between growing locations. Eleven proteins related to fungal infection were detected as were three proteins with effects based on growing location. These proteins belong to different protein groups involved in various cell functions: transcription regulation, defence response, nutrient reservoirs and starch biosynthesis. The results gave indications on plant defence strategies and changes as response to Fusarium infection in mature grains after a long infection period as well as being influenced by the growing location.
Application of 2‐D DIGE to formalin‐fixed, paraffin‐embedded tissues
Authors: Tanca Alessandro , Pagnozzi Daniela , Falchi Giovanni , Tonelli Roberto , Rocca Stefano , Roggio Tonina , Uzzau Sergio , Addis Maria Filippa
Published: January 2011

The ability to investigate the proteome of formalin‐fixed, paraffin‐embedded (FFPE) tissues can be considered a major recent achievement in the field of clinical proteomics. However, gel‐based approaches to the investigation of FFPE tissue proteomes have lagged behind, mainly because of insufficient quality of full‐length protein extracts. Here, the 2‐D DIGE technology was investigated for applicability to FFPE proteins, for internal reproducibility among replicate FFPE extracts, and for comparability between FFPE and fresh‐frozen tissue profiles. The 2‐D DIGE patterns obtained upon labeling and electrophoresis of replicate FFPE tissue extracts were highly reproducible, with satisfactory resolution and complexity. Moreover, the implementation of DIGE enabled to highlight and characterize the consistent differences found in the FFPE profiles compared with fresh‐frozen profiles, represented by an acidic shift, directly correlated to the protein pI value, and by a reduction in spot signal intensity, directly correlated to molecular weight and percentage of lysine residues. Being constantly and reproducibly present in all FFPE tissue extract replicates at similar extents, these modifications do not appear to hinder the comparative analysis of FFPE tissue extracts by 2‐D DIGE, opening the way to its application for the differential proteomic investigation of archival tissue repositories.
Catch me if you can: Mass spectrometry‐based phosphoproteomics and quantification strategies
Authors: Eyrich Beate , Sickmann Albert , Zahedi René Peiman
Published: January 2011

Phosphorylation of proteins is one of the most prominent PTMs and for instance a key regulator of signal transduction. In order to improve our understanding of cellular phosphorylation events, considerable effort has been devoted to improving the analysis of phosphorylation by MS‐based proteomics. Different enrichment strategies for phosphorylated peptides/proteins, such as immunoaffinity chromatography (IMAC) or titanium dioxide, have been established and constantly optimized for subsequent MS analysis. Concurrently, specific MS techniques were developed for more confident identification and phosphorylation site localization. In addition, more attention is paid to the LC‐MS instrumentation to avoid premature loss of phosphorylated peptides within the analytical system. Despite major advances in all of these fields, the analysis of phosphopeptides still remains far from being routine in proteomics. However, to reveal cellular regulation by phosphorylation events, not only qualitative information about the phosphorylation status of proteins but also, in particular, quantitative information about distinct changes in phosphorylation patterns upon specific stimulation is mandatory. Thus, yielded insights are of outstanding importance for the emerging field of systems biology. In this review, we will give an insight into the historical development of phosphoproteome analysis and discuss its recent progress particularly regarding phosphopeptide quantification and assessment of phosphorylation stoichiometry.