bluuebunny/crossref_metadata_2025 huggingface dataset:
A Multivariate Approach to a Meta-Analytic Review of the Effectiveness of the D.A.R.E. Program
Authors: Pan Wei , Bai Haiyan
Published: January 2009

The Drug Abuse Resistance Education (D.A.R.E.) program is a widespread but controversial school-based drug prevention program in the United States as well as in many other countries. The present multivariate meta-analysis reviewed 20 studies that assessed the effectiveness of the D.A.R.E. program in the United States. The results showed that the effects of the D.A.R.E. program on drug use did not vary across the studies with a less than small overall effect while the effects on psychosocial behavior varied with still a less than small overall effect. In addition, the characteristics of the studies significantly explained the variation of the heterogeneous effects on psychosocial behavior, which provides empirical evidence for improving the school-based drug prevention program.
Potential Mechanisms of Muscle Mitochondrial Dysfunction in Aging and Obesity and Cellular Consequences
Authors: Chanséaume Emilie , Morio Béatrice
Published: January 2009

Mitochondria play a key role in the energy metabolism in skeletal muscle. A new concept has emerged suggesting that impaired mitochondrial oxidative capacity in skeletal muscle may be the underlying defect that causes insulin resistance. According to current knowledge, the causes and the underlying molecular mechanisms at the origin of decreased mitochondrial oxidative capacity in skeletal muscle still remain to be elucidated. The present review focuses on recent data investigating these issues in the area of metabolic disorders and describes the potential causes, mechanisms and consequences of mitochondrial dysfunction in the skeletal muscle.
Parallel Synthesis of a Library of Symmetrically- and Dissymmetrically-disubstituted Imidazole-4,5-dicarboxamides Bearing Amino Acid Esters
Authors: Solinas Rosanna , DiCesare John  C. , Baures Paul  W.
Published: January 2009

The imidazole-4,5-dicarboxylic acid scaffold is readily derivatized with amino acid esters to afford symmetrically- and dissymmetrically-disubstituted imidazole-4,5-dicarboxamides with intramolecularly hydrogen bonded conformations that predispose the presentation of amino acid pharmacophores. In this work, a total of 45 imidazole-4,5-dicarboxamides bearing amino acid esters were prepared by parallel synthesis. The library members were purified by column chromatography on silica gel and the purified compounds characterized by LC-MS with LC detection at 214 nm. A selection of the final compounds was also analyzed by 1H-NMR spectroscopy. The analytically pure final products have been submitted to the Molecular Library Small Molecule Repository (MLSMR) for screening in the Molecular Library Screening Center Network (MLSCN) as part of the NIH Roadmap.
Influence of Surface Roughness Spatial Variability and Temporal Dynamics on the Retrieval of Soil Moisture from SAR Observations
Authors: Álvarez-Mozos Jesús , Verhoest Niko  E.C. , Larrañaga Arantzazu , Casalí Javier , González-Audícana María
Published: January 2009

Radar-based surface soil moisture retrieval has been subject of intense research during the last decades. However, several difficulties hamper the operational estimation of soil moisture based on currently available spaceborne sensors. The main difficulty experienced so far results from the strong influence of other surface characteristics, mainly roughness, on the backscattering coefficient, which hinders the soil moisture inversion. This is especially true for single configuration observations where the solution to the surface backscattering problem is ill-posed. Over agricultural areas cultivated with winter cereal crops, roughness can be assumed to remain constant along the growing cycle allowing the use of simplified approaches that facilitate the estimation of the moisture content of soils. However, the field scale spatial variability and temporal variations of roughness can introduce errors in the estimation of soil moisture that are difficult to evaluate. The objective of this study is to assess the impact of roughness spatial variability and roughness temporal variations on the retrieval of soil moisture from radar observations. A series of laser profilometer measurements were performed over several fields in an experimental watershed from September 2004 to March 2005. The influence of the observed roughness variability and its temporal variations on the retrieval of soil moisture is studied using simulations performed with the Integral Equation Model, considering different sensor configurations. Results show that both field scale roughness spatial variability and its temporal variations are aspects that need to be taken into account, since they can introduce large errors on the retrieved soil moisture values.
Development and Testing of Energetic Materials: The Concept of High Densities Based on the Trinitroethyl Functionality
Authors: Göbel Michael , Klapötke Thomas M.
Published: January 2009

The development of new energetic materials is an emerging area of materials chemistry facilitated by a worldwide need to replace materials used at present, due to environmental considerations and safety requirements, while at the same time securing high performance. The development of such materials is complex, owing to the fact that several different and apparently mutually exclusive material properties have to be met in order for a new material to become widely accepted. In turn, understanding the basic principles of structure property relationships is highly desirable, as such an understanding would allow for a more rational design process to yield the desired properties. This article covers the trinitroethyl functionality and its potential for the design of next generation energetic materials, and describes relevant aspects of energetic materials chemistry including theoretical calculations capable of reliably predicting material properties. The synthesis, characterization, energetic properties, and structure property relationships of several new promising compounds displaying excellent material properties are reported with respect to different kinds of applications and compared to standard explosives currently used. Based on a review of trinitroethyl‐containing compounds available in the literature, as well as this new contribution, it is observed that high density can generally be obtained in a more targeted manner in energetic materials taking advantage of noncovalent bonding interactions, a prerequisite for the design of next generation energetic materials.
N,N‐Dimethylformamide as a Reaction Medium for Metal Nanoparticle Synthesis
Authors: Pastoriza‐Santos Isabel , Liz‐Marzán Luis M.
Published: January 2009

The versatility of wet chemical methods has rendered them extremely popular for the preparation of metal nanoparticles with tailored size and shape. This Feature Article reviews the use of N,N‐dimethylformamide (DMF) for the reduction of metal salts, mainly Au and Ag, while also acting as a solvent. Apart from describing the ability of DMF to reduce metal salts, the effect of different parameters, such as the concentration of capping agent and metal precursors, the presence of preformed seeds acting as catalysts or their crystalline structure, on particle morphology are analyzed. Published reports on the use of different capping agents are summarized, with particular emphasis on the role of poly(vinylpyrrolidone) to determine the morphology of the particles. Finally, a brief overview is provided on the modulation of the optical response in DMF‐based metal nanoparticle colloids with tunable size and shape.
Enzymatic Production of l‐Menthol by a High Substrate Concentration Tolerable Esterase from Newly Isolated Bacillus subtilis ECU0554
Authors: Zheng Gao‐Wei , Yu Hui‐Lei , Zhang Jian‐Dong , Xu Jian‐He
Published: January 2009

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Enzymatic preparation of l‐menthol has been attracting much attention in the flavor and fragrance industry. A new ideal strain, Bacillus subtilis ECU0554, which exhibited high hydrolytic activity and excellent enantioselectivity towards l‐menthyl ester, has been successfully isolated from soil samples through enrichment culture and identified as Bacillus subtilis by 16S rDNA gene sequencing. The esterase extracted from B. subtilis ECU0554 (BSE) showed the best catalytic properties (E>200) for dl‐menthyl acetate among the five menthyl esters examined. Enantioselective hydrolysis of 100 mM dl‐menthyl acetate at 30°C and pH 7.0, using crude BSE as biocatalyst and 10% ethanol (v/v) as cosolvent, resulted in 49.0% conversion (3 h) and 98.0% ee for the l‐menthol produced, which were much better than those using commercial enzymes tested. Moreover, BSE exhibited strong tolerance against high substrate concentration (up to 500 mM), and the concentration of l‐menthol produced could reach as high as 182 mM, and more importantly, the optical purity of l‐menthol produced was kept above 97% ee, which were not found in previous reports. These results imply that BSE is a potentially promising biocatalyst for the large‐scale enzymatic preparation of l‐menthol. Using this excellent biocatalyst, the enzymatic production of l‐menthol will become a mild, efficient, inexpensive and easy‐to‐use “green chemistry” methodology.
Ruthenium‐Catalyzed CH Bond Activation of Michael Acceptors: An Unusual Reactivity Leading to Allylsilanes
Authors: Simon Marc‐Olivier , Martinez Rémi , Genêt Jean‐Pierre , Darses Sylvain
Published: January 2009

We report here an improved catalyst for the functionalization of Michael acceptors, involving CC bond formation via CH bond activation, using an in situ generated ruthenium active species. Moreover, on some particular substrates, the CH functionalization resulted unexpectedly in the formation of allylsilanes rather than in the expected conjugated adducts, affording a new straightforward methodology to access useful stereodefined trisubstituted allylsilanes via CH bond activation. Preliminary results have shown that they were reactive in the allylation of aldehydes, providing an access to alcohols bearing a quaternary carbon center.
A Catalytic Asymmetric Electrocyclization‐Protonation Reaction
Authors: Rueping Magnus , Ieawsuwan Winai
Published: January 2009

The first enantioselective Brønsted acid‐catalyzed electrocyclization‐protonation reaction has been developed which provides a number of different cyclopentenones in good yields and with high enantioselectivities. The stereodetermining step of this asymmetric Nazarov cyclization reaction is an asymmetric Brønsted acid‐catalyzed kinetic protonation.
Highly Efficient Iron(II) Chloride/N‐Bromosuccinimide‐Mediated Synthesis of Imides and Acylsulfonamides
Authors: Wang Feng , Liu Hongxia , Fu Hua , Jiang Yuyang , Zhao Yufen
Published: January 2009

We have developed a general and highly efficient iron(II) chloride/N‐bromosuccinimide (NBS)‐mediated method for the synthesis of imides and acylsulfonamides via couplings of thioesters with carboxamides/sulfonamides, and the method is simple, economical and shows practical advantages.
Elucidation of Architectural Requirements from a Spacer in Supported Proline‐Based Catalysts of Enantioselective Aldol Reaction
Authors: Goren Kerem , Kehat Tzofit , Portnoy Moshe
Published: January 2009

In order to delineate the properties of the spacer architecture responsible for the strong positive dendritic effect exhibited by polymer‐supported proline‐based catalysts, we prepared two series of polystyrene‐bound model catalysts. The first series was based on a linear and partially dendritic spacers (of reduced branching and valency) imitating the length of the second generation spacer, while the second series was based on the first generation dendron spacer with one functional (proline‐terminated) and one non‐functional arm. Comparative studies of the model and original (fully dendritic) catalysts in the asymmetric aldol reaction of aromatic aldehydes with acetone disclose the features characteristic to the dendritic architecture, such as proximity between the terminal catalytic units and enhanced branching, as crucial for inducing higher yield and enantioselectivity in catalysis.
Achieving state estimation equivalence for misassigned disturbances in offset‐free model predictive control
Authors: Rajamani Murali R. , Rawlings James B. , Qin S. Joe
Published: January 2009

Integrated white noise disturbance models are included in advanced control strategies, such as Model Predictive Control, to remove offset when there are unmodeled disturbances or plant/model mismatch. These integrating disturbances are usually modeled to enter either through the plant inputs or the plant outputs or partially through both. There is currently a lack of consensus in the literature on the best choice for the structure of this disturbance model to obtain good feedback control. We show that the choice of the disturbance model does not affect the closed‐ loop performance if appropriate covariances are used in specifying the state estimator. We also present a data based autocovariance technique to estimate the appropriate covariances regardless of the plant's true unknown disturbance source. The covariances estimated using the autocovariance technique and the resulting estimator gain are shown to compensate for an incorrect choice of the source of the disturbance in the disturbance model. © 2009 American Institute of Chemical Engineers AIChE J, 2009
The underrecognized progressive nature of N370S Gaucher disease and assessment of cancer risk in 403 patients
Authors: Taddei Tamar H. , Kacena Katherine A. , Yang Mei , Yang Ruhua , Malhotra Advitya , Boxer Michael , Aleck Kirk A. , Rennert Gadi , Pastores Gregory M. , Mistry Pramod K.
Published: January 2009

Mutations in GBA1 gene that encodes lysosomal glucocerebrosidase result in Type 1 Gaucher Disease (GD), the commonest lysosomal storage disorder; the most prevalent disease mutation is N370S. We investigated the heterogeneity and natural course of N370S GD in 403 patients. Demographic, clinical, and genetic characteristics of GD at presentation were examined in a cross‐sectional study. In addition, the relative risk (RR) of cancer in patients compared with age‐, sex‐, and ethnic‐group adjusted national rates of cancer was determined. Of the 403 patients, 54% of patients were homozygous (N370S/N370S) and 46% were compound heterozygous for the N370S mutation (N370S/other). The majority of N370S/N370S patients displayed a phenotype characterized by late onset, predominantly skeletal disease, whereas the majority of N370S/other patients displayed early onset, predominantly visceral/hematologic disease, P < 0.0001. There was a striking increase in lifetime risk of multiple myeloma in the entire cohort (RR 25, 95% CI 9.17–54.40), mostly confined to N370S homozygous patients. The risk of other hematologic malignancies (RR 3.45, 95% CI 1.49–6.79), and overall cancer risk (RR 1.80, 95% CI 1.32–2.40) was increased. Homozygous N370S GD leads to adult‐onset progressive skeletal disease with relative sparing of the viscera, a strikingly high risk of multiple myeloma, and an increased risk of other cancers. High incidence of gammopathy suggests an important role of the adaptive immune system in the development of GD. Adult patients with GD should be monitored for skeletal disease and cancers including multiple myeloma. Am. J. Hematol., 2009. © 2009 Wiley‐Liss, Inc.
Nanomedizin – Herausforderung und Perspektiven
Authors: Riehemann Kristina , Schneider Stefan W. , Luger Thomas A. , Godin Biana , Ferrari Mauro , Fuchs Harald
Published: January 2009

Die Anwendung nanotechnologischer Konzepte in der Medizin verbindet zwei große interdisziplinäre Wissenschaftsgebiete mit einem beispiellosen sozialen und ökonomischen Potenzial. Diese Nanomedizin nutzt die Errungenschaften beider Forschungsfelder, wobei die gemeinsame Basis die Untersuchung spezifischer Eigenschaften auf der Molekülebene ist. Mithilfe lokaler Sonden und molekularer Bildgebungstechniken können Oberflächen‐ und Grenzflächeneigenschaften auf der Nanometerskala an vorgegebenen Messpunkten charakterisiert werden, während es mit chemischen Methoden gelingt, Oberflächen kontrolliert zu modifizieren und zu adressieren. Beispiele hierfür sind neuartige Konzepte für den gezielten Wirkstofftransport, die Biokompatibilitätsoptimierung und neuroprothetische Anwendungen. Allerdings sind im Hinblick auf toxikologische sowie ethische Aspekte dieser Querschnittsdisziplin noch viele Fragen offen. Hier werden ausgewählte Entwicklungen nud Anwendungen der Nanomedizin besprochen.
XeF4 as a Ligand for a Metal Ion
Authors: Tavčar Gašper , Žemva Boris
Published: January 2009

Edles Molekül: [Mg(XeF2)(XeF4)](AsF6)2 ist die erste Koordinationsverbindung, in der XeF4 als an ein Metallzentrum gebundener Ligand vorliegt. Es ist auch die erste bekannte Verbindung, in der XeF2 und XeF4 gemeinsam an dasselbe Metallzentrum binden (siehe Struktur; lila Xe, grün F, grau Mg, gelb As).

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Palladium‐Catalyzed Substitution of Allylic Fluorides
Authors: Hazari Amaruka , Gouverneur Véronique , Brown John M.
Published: January 2009

Ein Sonderfall: Ungewöhnliche Substrate für die Tsuji‐Trost‐Allylierung sind Allylfluoride, die palladiumkatalysierte Substitutionen eingehen. Ihre Aktivität bei dieser Reaktion folgt der Reihe OCO2Me>OBz≫F≫OAc. Die klassische Stereoretention als Folge einer Serie von Inversionen tritt in diesem Fall nicht auf.

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High‐Purity Discrete PEG‐Oligomer Crystals Allow Structural Insight
Authors: French Alister C. , Thompson Amber L. , Davis Benjamin G.
Published: January 2009

Über kurz oder lang: Eine verbesserte Methode zur Synthese von Ethylenglycol (EG)‐Oligomeren eröffnet den Zugang zu 16‐ und 32‐meren, die rein genug für einen mehrfachen Einbau sind, sowie zum bisher längsten (48‐meren) einzelnen EG‐Oligomer. Die hohe Reinheit ermöglichte die ersten Kristallisationen und damit die ersten Einblicke in sekundäre 310‐helicale PEG‐Strukturen.

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Isoprene‐Assisted Radical Coupling of (Co)polymers Prepared by Cobalt‐Mediated Radical Polymerization
Authors: Debuigne Antoine , Jérôme Christine , Detrembleur Christophe
Published: January 2009

Polymere en bloc: Die Isopren‐unterstützte radikalische Kupplung (I‐ARC) von Polymeren, die durch Cobalt‐vermittelte radikalische Polymerisation präpariert wurden (siehe Bild), ist die erste effiziente Radikalkupplungsmethode, die nicht auf kurze Ketten beschränkt ist. Die Anwendung der I‐ARC auf AB‐Diblockcopolymere bietet einen direkten Zugang zu neuartigen symmetrischen ABA‐Triblockcopolymeren.

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A Phosphorus Analogue of Bis(η4‐cyclobutadiene)iron(0)
Authors: Wolf Robert , Slootweg J. Chris , Ehlers Andreas W. , Hartl František , de Bruin Bas , Lutz Martin , Spek Anthony L. , Lammertsma Koop
Published: January 2009

P macht's möglich: Angesichts der leichten oxidativen Synthese des gezeigten 16‐Elektronen‐Sandwichkomplexes [Fe(η4‐P2C2tBu2)2] ist gut denkbar, dass auch der schwer zu fassende Komplex [Fe(η4‐C4H4)2] mit reinen Kohlenwasserstoffliganden hergestellt werden könnte.

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Stable Aziridinium Salts as Versatile Intermediates: Isolation and Regio‐ and Stereoselective Ring‐Opening and Rearrangement
Authors: Song Hyun A. , Dadwal Mamta , Lee Yeseul , Mick Emily , Chong Hyun‐Soon
Published: January 2009

Eine nützliche Entdeckung: Aziridiniumbromide wurden zufällig bei der Bromierung von N,N‐dicarboxymethylierten β‐Aminoalkoholen entdeckt. Die regiospezifische Ringöffnung und Umlagerung der isolierten, erstaunlich stabilen Aziridiniumsalze liefert nützliche Moleküle einschließlich C‐funktionalisierter Oxomorpholine und α,β‐ungesättigter Amine.

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Compartmentalization of Chemically Separated Components into Droplets
Authors: Edgar J. Scott , Milne Graham , Zhao Yiqiong , Pabbati Chaitanya P. , Lim David S. W. , Chiu Daniel T.
Published: January 2009

Mehr als ein Tropfen im Meer: Die Kombination von Kapillarelektrophorese (CE) mit elektroosmotischer Tröpfchenerzeugung ermöglicht die Kompartimentalisierung von durch CE getrennten molekularen Komponenten in einzelnen Tröpfchen (siehe Bild; die grünen Balken repräsentieren die getrennten Analyte). Die tröpfchenweise separierten Banden können auf einem Chip untersucht oder isoliert und separat analysiert werden.

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Water as an Oxygen Source in the Generation of Mononuclear Nonheme Iron(IV) Oxo Complexes
Authors: Lee Yong‐Min , Dhuri Sunder N. , Sawant Sarvesh C. , Cho Jaeheung , Kubo Minoru , Ogura Takashi , Fukuzumi Shunichi , Nam Wonwoo
Published: January 2009

Mit Cer(IV) als Oxidationsmittel und Wasser als Sauerstoffquelle wurden einkernige Nichthäm‐Eisen(IV)‐Oxo‐Komplexe erhalten. Die in hoher Ausbeute verlaufende Oxygenierung organischer Substrate in diesem System (siehe Schema; Fe grün, O rot, N blau, C grau) wird durch Eisen(II)‐Komplexe katalysiert. Die Quelle des Sauerstoffs in den Eisen(IV)‐Oxo‐Komplexen und den oxygenierten Produkten wurde durch Isotopenmarkierung eindeutig bestimmt.

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Diastereoselective Synthesis of Hexahydropyrrolo[2,1‐b]oxazoles by a Rhodium‐Catalyzed Hydroformylation / Silica‐Promoted Deformylation Sequence
Authors: Vasylyev Maxym , Alper Howard
Published: January 2009

Fleetingly formyl: A new rhodium‐catalyzed hydroformylation reaction of N‐allyl oxazolidines, carried out under a CO/H2 atmosphere, followed by a diastereoselective deformylative cyclization affords hexahydropyrrolo[2,1‐b]oxazoles in good yields. The reaction proceeds by a unique hydroformylation–deformylation sequence in which the formyl group virtually substitutes for the {CH2O} fragment of the oxazolidine heterocycle.

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Aluminum Bases for the Highly Chemoselective Preparation of Aryl and Heteroaryl Aluminum Compounds
Authors: Wunderlich Stefan H. , Knochel Paul
Published: January 2009

Selective CH activation with a series of neutral aluminum trisamide bases led to a wide range of polyfunctional aryl and heteroaryl aluminum reagents. Ester and cyano groups are stable under the reaction conditions for this direct alumination, and donor oxygen substituents are efficient directing groups. High metalation regioselectivities were observed with O,S and N,S heterocycles (see example).

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A Phosphorus Analogue of Bis(η4‐cyclobutadiene)iron(0)
Authors: Wolf Robert , Slootweg J. Chris , Ehlers Andreas W. , Hartl František , de Bruin Bas , Lutz Martin , Spek Anthony L. , Lammertsma Koop
Published: January 2009

P makes it possible: The convenient oxidative synthesis of the 16‐electron organophosphorus iron sandwich complex [Fe(η4‐P2C2tBu2)2] (see structure) suggests that the elusive all‐carbon complex [Fe(η4‐C4H4)2] is a viable synthetic target.

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Stable Aziridinium Salts as Versatile Intermediates: Isolation and Regio‐ and Stereoselective Ring‐Opening and Rearrangement
Authors: Song Hyun A. , Dadwal Mamta , Lee Yeseul , Mick Emily , Chong Hyun‐Soon
Published: January 2009

Rock trapping and exploration: Aziridinium bromide salts were discovered serendipitously during bromination of N,N‐dicarboxymethylated β‐amino alcohols. Regiospecific ring‐opening and rearrangement of the isolated, surprisingly stable aziridinium salts produces useful molecules including C‐functionalized oxomorpholines and α,β‐unsaturated amines.

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Characterization and application of grafted polypropylene and polystyrene treated with epichlorohydrin coupled with cellulose or starch for immobilization processes
Authors: El‐Arnaouty M. B. , Eid M. , Atia K. S. , Dessouki A. M.
Published: January 2009

The direct‐irradiation‐induced grafting of acrylamide onto polypropylene films and polystyrene films with crosslinking epichlorohydrin (Epi) as a spacer was studied. The reaction of polyamide–Epi with cellulose and starch was carried out. Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis were carried out before and after the enzyme was immobilized to confirm the characterization of the polymer and the α‐amylase enzyme‐immobilized one. The physicochemical parameters of the immobilized enzymes were measured, and the kinetics of the coenzyme–polymer‐catalyzed reactions and stability were investigated. A direct comparison was made between the activities of the free and immobilized preparations. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Aging and annealing behavior of polycarbonate surfaces modified by direct‐current glow discharge in air
Authors: Panwar Amrish K. , Barthwal S. K. , Ray S.
Published: January 2009

Aging and annealing a polycarbonate (PC) polymer surface treated by direct‐current (dc) glow discharge tend to revert it back to its virgin (pristine) state existing before surface modification by glow discharge. This structural recovery during aging and annealing has been studied in terms of the contact angles of test liquids and surface energy and correlated to the parameters of surface treatment such as the treatment time and power. Samples stored in hydrophobic environments such as air and treated by dc glow discharge at higher power levels show less recovery during aging than those treated at lower power levels. Similarly, a longer exposure time at a power level of 2.04 W decreases the extent of structural recovery in terms of surface energy during aging in air. At higher power levels, the higher kinetic energy of plasma species involved during dc glow discharge results in greater thickness of the damaged layer of the polymer surface, and so a PC sample exposed to dc glow discharge at a higher temperature also recovers at a slower rate during the initial phase of aging, whereas samples with surfaces modified by dc glow discharge at room temperature but annealed at a higher temperature show a relatively rapid recovery during the initial phase of aging. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Friction and wear behavior of glass fabric/phenolic resin composites with surface‐modified glass fabric
Authors: Su Feng‐Hua , Zhang Zhao‐Zhu
Published: January 2009

Untreated, air‐plasma‐bombarded, and β‐aminoethyltrimethoxylsilane‐silanized glass fabric (GF) was used to prepare GF/phenolic composites by dip coating in a phenolic adhesive resin and successive curing. The tribo‐performances of these GF/phenolic composites sliding against AISI‐1045 steel were evaluated with a pin‐on‐disc wear tester. The chemical composition of the untreated and surface‐treated GF was analyzed with Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The interfacial regions between the phenolic resin and GF and the worn surfaces of the composites were analyzed with scanning electron microscopy. The results show that the GF/phenolic composite with β‐aminoethyltrimethoxylsilane‐silanized GF had the highest load‐carrying capacity and best tribo‐performance, and it was followed by the composite with plasma‐treated GF. The improved tribo‐performance of the GF/phenolic composite made of surface‐treated GF was attributed to the strengthened interfacial bonding between the treated GF and the phenolic adhesive resin. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Enhanced crystallization of poly(L‐lactide‐co‐ε‐caprolactone) in the presence of water
Authors: Saha Swapan Kumar , Tsuji Hideto
Published: January 2009

Poly(L‐lactide‐co‐ε‐caprolactone) [P(LLA‐CL)], which is used in biodegradable biomedical materials such as drug‐delivery systems, surgical sutures, orthopedics, and scaffolds for tissue engineering, has been reported to crystallize upon storage in a dry state even at room temperature; this results in rapid changes in the mechanical properties. In biomedical applications, P(LLA‐CL) is used in the presence of water. This study investigated the effects of water on the crystallization of P(LLA‐CL) at 37°C in phosphate buffered solution, which was anticipated to alter its mechanical properties and hydrolytic degradation behavior. Surprisingly, the crystallinity of P(LLA‐CL) in the presence of water rapidly increased in 6–12 h and then slowly increased up to 120 h. The period of time for the initial rapid crystallization increase in the presence of water was much shorter than that in the absence of water. The obtained information would be useful for the selection, preparation, and use of P(LLA‐CL) in various biomedical applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Development of conducting polyaniline/poly(lactic acid) nanofibers by electrospinning
Authors: Picciani Paulo H. S. , Medeiros Eliton S. , Pan Zhongli , Orts William J. , Mattoso Luiz H. C. , Soares Bluma G.
Published: January 2009

Ultrafine fibers consisting of blends of polyaniline doped with p‐toluene sulfonic acid and poly(L‐lactic acid) were prepared by electrospinning. The presence of polyaniline resulted in fibers with diameters as thin as 100–200 nm and a significant reduction of bead formation. These fibers were visually homogeneous, and this indicated good interactions between the components of the polyaniline/poly(L‐lactic acid) blend. The high interaction between the components and the rapid evaporation of the solvent during electrospinning resulted in nanofibers with a lower degree of crystallinity in comparison with cast films. The electrical conductivity of the electrospun fiber mats was lower than that of blend films produced by casting, probably because of the lower degree of crystallinity of the polyaniline dispersion and the high porosity of the nonwoven mat. This novel system opens up new and interesting opportunities for applications in biomedical devices, biodegradable materials, and sensors, among other things. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Crosslinking reactions of oxidized cellulose fiber. II. Reactions between dialdehyde cellulose and chito‐oligosaccharides on lyocell fabric
Authors: Han Samsook , Lee Muncheul
Published: January 2009

Antimicrobial nonfibrillated lyocell fibers were developed by crosslinking reactions between dialdehyde cellulose and chito‐oligosaccharides. Partially oxidized lyocell fibers with sodium metaperiodate were successfully crosslinked with two water‐soluble chito‐oligosaccharides with different molecular weights by Schiff base formation and were reduced with sodium borohydride. Infrared spectroscopy measurements showed the characteristic absorption bands caused by the functional groups of each reaction product. The surface chemical compositions of the modified fibers were analyzed with electron spectroscopy. O1s intensities decreased with the oxidation and crosslinking reaction, whereas N1s intensities increased with the crosslinking reaction. According to the curve fittings, C1s spectra were divided into CH, CO/CN, CO, and COO peaks, and their relative peak areas confirmed the reaction results. The degree of fibrillation of the crosslinked fibers decreased with the oxidation levels and chito‐oligosaccharide concentrations and increased with the molecular weight of the chito‐oligosaccharide. Furthermore, the chito‐oligosaccharide‐treated lyocell fibers exhibited antimicrobial activity, especially when treated with a chito‐oligosaccharide of a low weight‐average molecular weight. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and characterization of castor‐oil‐modified hyperbranched polyurethanes
Authors: Karak Niranjan , Rana Sravendra , Cho Jae Whan
Published: January 2009

A series of castor‐oil‐modified hyperbranched polyurethanes were synthesized via an A2 + B3 approach based on castor oil, macroglycol poly(ϵ‐caprolactone)diol or poly(ethylene glycol) (PEG), and diphenyl methane diisocyanate, with or without a chain extender. The yield of the product was 95%, and the polymers were soluble in common organic polar solvents. The synthesized polymers were characterized with Fourier transform infrared spectroscopy, NMR, wide‐angle X‐ray diffraction, and gel permeation chromatography measurements. The degree of branching of the polymers was calculated from their respective 1H‐NMR spectra with the help of model compounds and found to be varied from 0.7 to 0.8. The hard‐segment content, the nature of the macroglycol, and the composition of the polymers had prominent effects on the thermal degradation and crystallization of the hyperbranched polymers. The crystallization of poly(ϵ‐caprolactone) and PEG as soft segments occurred well in the hyperbranched polymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of a functional poly(ether imide) membrane for potential alkaline fuel cell applications: Chloromethylation
Authors: Wang Guigui , Weng Yiming , Zhao Jun , Chen Rongrong , Xie Dong
Published: January 2009

We have developed a novel poly(ether imide)‐based alkaline anion‐exchange membrane. The effects of several important parameters on the chloromethylation of the membrane have been investigated. These parameters include the reaction temperature, reaction time, concentration of the chloromethylation agent, concentration of the polymer, and amount of the catalyst. The results show that all the studied parameters have significant impacts on chloromethylation. Among them, the concentration of the chloromethylation agent plays a key role in increasing the attachment of chloromethyl functional groups onto the polymer. It ha been found that gelation can be avoided if these reaction parameters are controlled. This study also provides useful information for the successful chloromethylation of other membrane‐related polymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and characterization of biodegradable polycaprolactone/multiwalled carbon nanotubes nanocomposites
Authors: Yeh Jen‐Taut , Yang Ming‐Chien , Wu Ching‐Ju , Wu Chin‐San
Published: January 2009

Blends of the biodegradable polycaprolactone (PCL) and multiwalled carbon nanotubes (MWNTs) were prepared by means of a melt blending method. To conquer the poor compatibility between PCL and MWNTs, the acrylic acid grafted polycaprolactone (PCL‐g‐AA) and the multihydroxyl functionalized MWNTs (MWNTs‐OH) were used as alternatives for the preparation of blends. As the comparison between PCL‐g‐AA/MWNTs‐OH and PCL/MWNTs blends, the former gave much better thermal and mechanical properties than the latter; for examples, 77°C increase in the initial decomposition temperature and 13.3 MPa in the tensile strength at break with the addition of only 5 wt %, due to the formation of ester groups through the reaction between carboxylic acid groups of PCL‐g‐AA and hydroxyl groups of MWNTs‐OH. Finally, the optimal amount of MWNTs‐OH was 5 wt % because excess MWNTs‐OH caused separation of the organic and inorganic phases and lowering their compatibility. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Cure kinetics of an epoxy resin containing naphthyl/dicyclopentadiene moieties and bis‐phenoxy (3‐hydroxy) phosphine oxide system and properties of its cured polymer
Authors: Ren Hua , Sun Jianzhong , Zhao Qian , Zhiqi Cai , Ling Qincai , Zhou Qiyun
Published: January 2009

The cure kinetics of naphthyl/dicyclopentadiene epoxy resin and bisphenoxy (3‐hydroxy) phosphine oxide was investigated by differential scanning calorimetry (DSC) under nonisothermal and isothermal condition. The advanced isoconversional method was used to study the nonisothermal DSC data, the effective activation energy of the curing system in the early stage agreed with the value calculated from the Kissinger model and then increased because of the hindrance of molecular mobility. Autocatalytic behavior was shown in the isothermal DSC measurement, which was well described by Kamal model in the early curing stage. In the later stage, a crosslinked network structure was formed and the curing reaction was mainly controlled by diffusion. The diffusion factor was introduced to optimize the Kamal model and correct the deviation of the calculated data. The physical properties of the cured polymer were evaluated by dynamic mechanical thermal analyses, thermogravimetric analyses, and limiting oxygen index test, which exhibited relatively high glass transition temperature, thermal stability, and flame retardancy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mechanical and thermal properties of LDPE‐cellulose acetate phthalate blends—Effect of maleic anhydride‐grafted LDPE compatibilizer
Authors: Sailaja R. R. N. , Seetharamu S.
Published: January 2009

Biodegradable blends of LDPE and cellulose acetate phthalate have been prepared. Maleic anhydride‐grafted LDPE has been added as a compatibilizer to this blend. The elastic modulus and tensile strength has been considerably improved by adding LDPE‐g‐maleic anhydride compatibilizer. Scanning electron microscope micrographs reflected the observed results for the increase in mechanical properties of the blend. Further blend morphology exhibited a deformed matrix for the compatibilized blends. Thermogravimetric analysis studies showed two‐stage degradation for the blends. Differential scanning calorimetry thermograms showed a loss of crystallinity for the LDPE phase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Evaluation of current densities and total contact currents in occupational exposure at 400 kV substations and power lines
Authors: Korpinen Leena H. , Elovaara Jarmo A. , Kuisti Harri A.
Published: January 2009

This investigation studied the current densities in the neck and total contact currents in occupational exposure at 400 kV substations and power lines. Eight voluntary workers simulated their normal work tasks using the helmet–mask measuring system. In all, 151 work tasks with induced current measurements were made. Work situations were: tasks in 400 kV substations, tasks in 400–110 kV towers and the cutting of vegetation under 400 kV power lines. The average current density in the neck was estimated from the current induced in the helmet. The calculated maximum average current densities in the neck varied from 1.5 to 6.4 mA/m2 and the maximum total contact currents from 66.8 to 458.4 µA. The study shows that the maximum average current densities and the total contact currents (caused by electric field) in occupational exposure at 400 kV substations and power lines does not exceed the limit and action values (10 mA/m2 and 1 mA) of the new EU‐directive 2004/40/EC (live‐line bare‐hand works excluded). Bioelectromagnetics 30:231–240, 2009. © 2009 Wiley‐Liss, Inc.
Mobile phone use and location of glioma: A case–case analysis
Authors: Hartikka Hanna , Heinävaara Sirpa , Mäntylä Riitta , Kähärä Veikko , Kurttio Päivi , Auvinen Anssi
Published: January 2009

We assessed a new approach for evaluating the glioma risk among users of mobile phones to focus on the part of the brain most heavily exposed to radiofrequency electromagnetic fields from mobile phones. The tumor midpoint was defined from radiological imaging. A case–case analysis with 99 gliomas was performed using logistic regression. The exposed cases were those with the tumor mid‐point within 4.6 cm from the line between the mouth and the external meatus of the ear, representing the most likely location of the mobile phone (the source of exposure). Alternative analyses based on various indicators of mobile phone use as the outcome were also carried out. The majority of cases were regular mobile phone users. A slightly higher proportion of gliomas among mobile phone users than non‐users occurred within 4.6 cm from the presumed location of the mobile phone (28% vs. 14%). Modestly elevated odds ratios were observed for several indicators of mobile phone use, but without an exposure gradient. The highest odds ratios were found for contralateral and short‐term use. Our results, though limited by the small sample size, demonstrate that detailed information on tumor location allows evaluation of the risk related to the most heavily exposed part of the brain, representing direct evaluation of the possible local carcinogenic effects of the radiofrequency fields. However, field strength varies between users and over time also within a given anatomic site, due to the output power of the phone. Collaborative analysis of a larger sample is planned. Bioelectromagnetics 30:176–182, 2009. © 2009 Wiley‐Liss, Inc.
Enrichment of protein–RNA crosslinks from crude UV‐irradiated mixtures for MS analysis by on‐line chromatography using titanium dioxide columns
Authors: Richter Florian Martin , Hsiao He‐Hsuan , Plessmann Uwe , Urlaub Henning
Published: January 2009

UV crosslinking is an appropriate method to identify proteins that directly contact nucleic acid, e.g., RNA. In combination with modern mass spectrometric (MS) analysis such an approach provides the opportunity to reveal not only the nature of the crosslinked proteins but also to identify the actual crosslinking sites between the protein and the nucleic acid. However, the relatively low yield in UV‐induced crosslinking makes it difficult to identify in particular those species by MS that represent peptide–nucleic acid conjugates, as the great excess of noncrosslinked material interferes with their detection in MS. Here, we present an automated enrichment strategy of crosslinked peptide–RNA oligonucleotides derived from crude mixtures of UV‐irradiated ribonucleoprotein (RNP) particles that uses TiO2 columns integrated within a two‐dimensional (2D) nanoliquid chromatography (LC) system. The setup combines two C18 precolumns, a TiO2 enrichment column and a nanoanalytical column. It allows the removal of the noncrosslinked RNA and protein moiety and the specific enrichment of crosslinked peptide–RNA conjugates so that UV‐irradiated and subsequently completely hydrolyzed RNP complexes can directly be loaded and analyzed by MS. In this feasibility study, we demonstrate the specific enrichment of peptide–RNA oligonucleotides derived from UV‐irradiated native spliceosomal U1 snRNPs and spliceosomal [15.5K‐61K‐U4atac snRNA] complex reconstituted in vitro. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 297–309, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
New biotin derivatives for labeling and solubilizing IgG peptides
Authors: Bartos Ádám , Uray Katalin , Hudecz Ferenc
Published: January 2009

In this article, we describe the synthesis of a new class of oligoethylene‐glycol based water‐soluble biotin derivatives for labeling of peptides with limited solubility in aqueous solution. First 4,7,10‐trioxa‐1,13‐tridecanediamine was mono‐acetylated by succinic anhydride (Ttds) followed by the introduction of N‐Fmoc‐protecting group using Fmoc‐N‐hydroxysuccinimide ester. The resulting compound (Fmoc‐Ttds) was used for the preparation of 4,7,10‐trioxa‐1,13‐tridecanediamine di‐ and trimers on solid phase using Wang resin by carbodiimide coupling method. After attachment of Fmoc‐Ttds to the solid support, the Fmoc‐blocking group was removed and the Ttds‐modified resin was repeatedly acylated by Fmoc‐Ttds or by biotin using PyBOP/HOBt active ester reaction. Finally the product [Fmoc‐(Ttds)n or biotinyl‐(Ttds)n (where n = 1, 2 or 3)] was removed from the resin by trifluoroacetic acid in the presence of water. After appropriate HPLC purification and characterization (MS) biotinyl‐(Ttds)n (where n = 1, 2 or 3) were introduced to the N‐terminal of poorly soluble oligopeptides by solid phase peptide synthesis. We found that this new class of biotinylating reagent could be prepared easily and in good yield. Comparative solubility measurements suggest that the incorporation of these moieties–depending on the number of Ttds unit–could enhance water solubility. © 2009 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 92: 110–115, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Spectral kinetic modeling and long‐term behavior assessment of Arthrospira platensis growth in photobioreactor under red (620 nm) light illumination
Authors: Farges Bérangère , Laroche Céline , Cornet Jean‐François , Dussap Claude‐Gilles
Published: January 2009

The ability to cultivate the cyanobacterium Arhtrospira platensis in artificially lightened photobioreactors using high energetic efficiency (quasi‐monochromatic) red LED was investigated. To reach the same maximal productivities as with the polychromatic lightening control conditions (red + blue, P/2e− = 1.275), the need to work with an optimal range of wavelength around 620 nm was first established on batch and continuous cultures. The long‐term physiological and kinetic behavior was then verified in a continuous photobioreactor illuminated only with red (620 nm) LED, showing that the maximum productivities can be maintained over 30 residence times with only minor changes in the pigment content of the cells corresponding to a well‐known adaptation mechanism of the photosystems, but without any effect on growth and stoichiometry. For both poly and monochromatic incident light inputs, a predictive spectral knowledge model was proposed and validated for the first time, allowing the calculation of the kinetics and stoichiometry observed in any photobioreactor cultivating A. platensis, or other cyanobacteria if the parameters were updated. It is shown that the photon flux (with a specified wavelength) must be used instead of light energy flux as a relevant control variable for the growth. The experimental and theoretical results obtained in this study demonstrate that it is possible to save the energy consumed by the lightening device of photobioreactors using red LED, the spectral range of which is defined according to the action spectrum of photosynthesis. This appears to be crucial information for applications in which the energy must be rationalized, as it is the case for life support systems in closed environments like a permanent spatial base or a submarine. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Application of spreadsheets in developing flexible multiple‐reach and multiple‐branch methods of Muskingum flood routing
Authors: Hosseini S.M.
Published: January 2009

Muskingum method which is covered in most hydraulic engineering courses and textbooks is widely used for hydrologic flood routing in rivers. In this paper, computational and optimization capabilities of Microsoft Excel spreadsheet is used to perform multiple‐reach Muskingum flood routing in a river for which observed inflow and outflow hydrographs are available and its storage‐discharge relationship is highly non‐linear. The employed method is straightforward and results in better accuracy compared with traditional methods. It is also illustrated that the proposed computational procedure in the spreadsheets can be extended to flood routing in more complex river systems such as branched systems. Considering all these, from educational point of view, a main conclusion is that the results of the study significantly improve the methodologies for teaching Muskingum flood routing in complex river systems. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 17: 448–454, 2009; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20234