bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of unsaturated keto‐groups on physico‐mechanical and thermal properties of modified polystyrene
Authors: Cerit Alaaddin , Ahmetli Gulnare , Kurbanli Refika
Published: March 2011

Polystyrene (PS), after polyolefins, is the most widespread polymer both in industry and daily life, successfully replacing some natural raw materials. In this study, as a serial of our previous study, modified polystyrene containing acetyl group (CH3CO‐) was used as a raw material and condensation reaction was performed in basic medium with aliphatic saturated and unsaturated aldehydes. The structures of modified polystyrenes with unsaturated keto‐groups were investigated by chemical and spectral (FTIR vs. 1H NMR) analyses. The effect of the functional groups bound to the structure of the polymer on physicomechanical and thermal properties of modified polystyrene was investigated. As a result, condensation products of modified polystyrenes with crotonaldehyde and cinnamaldehyde had higher physicomechanical properties and were more stable against the thermal destruction at high temperatures. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Removal of metallic ions from ethanol solutions with modified natural cotton fiber
Authors: Teixeira Claudinei F. , Nesello Dariane , Anizelli Pedro R. , Gardes Bernard J. L. , Almeida Flaveli A. S. , Alfaya Antonio A. S. , Gushikem Yoshitaka , Alfaya Rení V. S.
Published: March 2011

A new material of cotton fiber/Al2O3/SiPy+Cl−, COTALPy, was prepared containing on its surface the polymer silsesquioxane 3‐n‐propylpyridinium chloride strongly adhered. This new composite based on long fibers of natural cotton is chemically stable and had its adsorption properties studied. The COTALPy presented a maximum ionic exchange capacity of 0.85 mmol g−1 by potentiometric titulation. The adsorption isotherms of CuCl2, ZnCl2, CdCl2, NiCl2, and FeCl2 in ethanol solutions were determined for each metal. The adsorption process was studied and data compared with the Langmuir model. The maximum adsorption capacities (in mmol g−1) were: CuCl2 = 0.20, ZnCl2 = 0.18, CdCl2 = 0.35, NiCl2 = 0.22, and FeCl2 = 0.68. Real samples of fuel ethanol were eluted through a column containing the COTALPy, and it presented high‐practical potential for removal of metallic ions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Toughening of bone cement using nanoparticle: The effect of solvent
Authors: Misra Nira , Kapusetti Govinda , Jaiswal Shilpa , Maiti Pralay
Published: March 2011

Drawbacks of poly(methyl methacrylate) (PMMA)‐based bone cement as a grouting agent for in vivo fixation of orthopedic and dental implants such as considerable low mechanical strength have been improved using nanotechnology. Bone cement‐layered silicate nanocomposites have been prepared without any heat treatment in the presence of polar (dimethyl formamide, DMF) and nonpolar (benzene) solvents. Solvents have been removed completely from the bone cement after its preparation. Nanostructure is very much dependent on the solvent used for nanocomposite preparation, and benzene‐based nanocomposites are highly intercalated, whereas DMF‐based nanocomposites do not exhibit intercalation. Thermal stability of bone cement has improved in the presence of nanoclays. The relative enhanced interaction in case of benzene‐based nanocomposites has been shown through FTIR and UV–vis studies. The significant improvement in modulus and toughness of bone cement has been demonstrated in the presence of minimum amount of nanoclay for benzene‐based nanocomposites, whereas no change in modulus and reduced toughness have been observed for DMF‐based nanocomposites. The decrease of contact angle has been witnessed with increasing nanoclay concentration indicating better hydrophilic materials suitable for biomedical applications for greater cell growth. The reason for varying property enhancement in different solvents has been discussed considering the polarity effect and interactions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
A real‐time study on the evolution of the degradation of polypropylene during mixing process
Authors: Wang Xiao , Yu Wencan , Nie Qunlian , Guo Yu , Du Juan
Published: March 2011

A real‐time study to the evolution of the mechanisms of degradation of both PP powder and PP granular during the mixing process was achieved. A quantitative analysis of combination of the rheological torque‐time curves obtained by a Haake rheometer with FTIR spectra was made. The construction of a series of the characteristic functions of the torque‐time curve and the FTIR characteristic functions for polypropylene (PP) made the real time and quantitative analysis relatively profound. By means of these characteristic functions, the characters of the mechanisms of thermooxidative degradation, and the mechanism of mechanochemical degradation for PP were investigated. Two criterions for the mechanism of thermooxidative degradation and the mechanism of mechanochemical degradation were obtained. In the thermooxidative treatment process and the mixing process, the necessary condition for the significant occurrence of thermooxidative degradation of PP is Δhr (i) > 0.05, whereas the sufficient condition for the significant occurrence of mechanochemical degradation is Δhr (i) ≤ 0.05 (Dl (i) < 0, and i > 1). A detailed description of the evolutions of the degradations for both the PP granules in which an antideterionant was added and the PP powder without any antideterionant was made. The roles and the evolutions of both the mechanism of thermooxidative degradation and the mechanism of mechanochemical degradation were discussed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Pharmacokinetic interactions between ciprofloxacin and itraconazole in healthy male volunteers
Authors: Sriwiriyajan Somchai , Samaeng Maseetoh , Ridtitid Wibool , Mahatthanatrakul Werawath , Wongnawa Malinee
Published: March 2011

Objective. To investigate the pharmacokinetic interaction between ciprofloxacin and itraconazole in healthy male volunteers. Methods. Ten healthy male volunteers were assigned into a 2‐sequence, 3‐period pharmacokinetic interaction study. In phase 1, all subjects were randomly assigned to receive 500 mg of ciprofloxacin alone and 200 mg of itraconazole alone twice daily for 7 days with a 14 day wash‐out period in a crossover design. Phase 2 was performed 14 days after finishing phase 1, all subjects received 500 mg of ciprofloxacin in combination with 200 mg of itraconazole twice daily for 7 days. Ciprofloxacin and itraconazole pharmacokinetics were studied and adverse effects noted. Results. Ciprofloxacin significantly increased the Cmax and AUC0 − ∞ of itraconazole by 53.13% and 82.46%, respectively. The half‐life and CL of itraconazole were not changed significantly. The combination of itraconazole and ciprofloxacin could therefore result in an increase in adverse drug reactions. Conversely, itraconazole had no significant effect on the pharmacokinetics of ciprofloxacin. Conclusion. Ciprofloxacin decreases the metabolism of itraconazole, most likely through inhibition of CYP3A4. The dosage of itraconazole should be reduced and its therapeutic outcome should be monitored closely when these two agents are concomitantly administered. Copyright © 2011 John Wiley & Sons, Ltd.
Entwicklung eines baupraktischen Näherungsverfahrens zur Beurteilung der Zuverlässigkeit von Massivbrücken auf der Grundlage der Ergebnisse von Bauwerksüberprüfungen
Authors: Braml Thomas , Keuser Manfred , Bergmeister Konrad
Published: March 2011

Im vorliegenden Teil 2 des Beitrags wird die Entwicklung des baupraktischen Näherungsverfahrens für die Beurteilung der Zuverlässigkeit von Massivbrücken im Rahmen der RI‐EBW‐PRÜF vorgestellt. Wesentlicher Inhalt ist dabei die Modellierung der Modellunsicherheit Bauwerksprüfer, da die Bewertung der Mängel und Schäden an einem Brückenbauwerk durch den jeweiligen Bauwerksprüfer einen entscheidenden Einfluss auf die Zustandsbewertung hat. Zudem wird auf die Dimensionsanalyse von Grenzzustandsfunktionen näher eingegangen, da damit bei geschickter Normierung eine allgemein gültige Anwendung des Verfahrens erreicht werden kann. Die Anwendung des Verfahrens erfolgt mit einem Software‐Tool, das abschließend vorgestellt wird. In Teil 1 des Beitrags wurden die Grundlagen des Verfahrens sowie die Entwicklung der veränderten stochastischen Material‐ und Geometrieparameter infolge Schädigung behandelt.

Development of an Approximation Procedure for a Structural Reliability Assessment of Reinforced Concrete Bridges on the Basis of the Results from Bridge Inspection

Part 2 of the paper shows the development of the approximation procedure for the reliability assessment of reinforced concrete bridges according to RI‐EBW‐PRÜF. An essential part of this is the development carried out by the model uncertainty bridge inspector, as the respective bridge inspector's individual assessment of the damage of a bridge has a decisive influence on the condition evaluation. Furthermore, the dimensional analyses of ultimate limit states are shown, as the general use of the developed methodology can be achieved with an ingenious standardization. The application of the procedure with the developed software tool is presented in conclusion. Part 1 of the two papers describes the basics of the methodology and shows the development of the stochastic models for the material and geometry parameters which have changed as a result of damage.
Betonplatten unter Stoßbelastung – Fallturmversuche
Authors: Hummeltenberg Anja , Beckmann Birgit , Weber Tony , Curbach Manfred
Published: March 2011

In dieser Arbeit werden Fallturmexperimente an Stahlbetonplatten vorgestellt, die an der Technischen Universität Dresden durchgeführt wurden. Es wurden dabei Fallhöhen von bis zu 9 m realisiert. Eine Motivation für diese Experimente war es, das Wissen über nachträgliche Verstärkung von Stahlbetonplatten gegen Steinschlag oder harten Fahrzeuganprall zu erweitern und Möglichkeiten einer nachträglichen Struktursicherung näher zu untersuchen. Die experimentelle Zielstellung war daher, den Einfluss von Stoßgeschwindigkeit, unterschiedlichen Verstärkungsarten und Betonfestigkeiten auf das lokale Materialverhalten und globale Tragverhalten von Platten zu untersuchen. Für zwei der insgesamt 15 Platten wurden zusätzlich zur Standardbewehrung Bügel eingebaut, um die Durchstanzfestigkeit der Platten zu erhöhen. Für einen Teil der Versuchsplatten wurden Stahl‐ bzw. Carbontextilien als nachträgliche Verstärkung verwendet. Dabei konnte festgestellt werden, dass eine derartige nachträgliche textile Verstärkung das komplette Durchschlagen des Impaktors verhindert und daher eine wirksame Schutzmaßnahme, beispielsweise für Steinschlaggalerien, darstellt.

Concrete Slabs under Impact Load – Drop Tower Experiments

Impact experiments on reinforced concrete slabs are presented in this work. In order to analyse the behaviour of concrete under high strain rates, an impact mass was dropped from the maximum height of 9 m onto quadratic concrete slabs with a side length of 1 m.

The aim of this work was to enlarge knowledge about subsequent structure protection against rock fall or vehicle impact. With this intention, experimental studies on impact velocity, reinforcement techniques were done to determine the influence to local material behaviour and global structure behaviour. Supplemental steel stirrup reinforcement was added to two of the 15 concrete slabs to increase punching resistance. Subsequent textile reinforcement was applied on six concrete slabs using steel fabric reinforcement as well as carbon fabric reinforcement. As a main result of this study it is shown, that a subsequent textile reinforcement prevents the perforation of the slab. For this reason, textile reinforcement can, for example, be used for protection component in rock fall galleries.
Bauen mit Beton
Authors: Bollinger Klaus
Published: March 2011

Ein Bericht basierend auf dem Impulsvortrag “Bauen mit Beton” anlässlich des Doktorandensymposiums/51. Forschungskolloquiums des DAfStb am 11. und 12. November 2010 an der TU Kaiserslautern
Peptide Structure Stabilization by Membrane Anchoring and its General Applicability to the Development of Potent Cell‐Permeable Inhibitors
Authors: Johannessen Liv , Remsberg Jarrett , Gaponenko Vadim , Adams Kristie M. , Barchi Joseph J. , Tarasov Sergey G. , Jiang Sheng , Tarasova Nadya I.
Published: March 2011

Isolated protein motifs that are involved in interactions with their binding partners can be used to inhibit these interactions. However, peptides corresponding to protein fragments tend to have no defined secondary or tertiary structure in the absence of scaffolding by the rest of protein molecule. This results in low inhibitor potency. NMR and CD spectroscopy studies of lipopeptide inhibitors of the Hedgehog pathway revealed that membrane anchoring allows the cell membrane to function as a scaffold and facilitate the folding of short peptides. In addition, lipidation enhances cell permeability and increases the concentration of the compounds near the membrane, thus facilitating potent inhibition. The general applicability of this rational approach was further confirmed by the generation of selective antagonists of the insulin‐like growth factor 1 receptor with GI50 values in the nanomolar range. Lipopeptides corresponding to protein fragments were found to serve as potent and selective inhibitors of a number of nondruggable molecular targets.
Influence of Substrate Dideuteration on the Reaction of the Bifunctional Heme Enzyme Psi Factor Producing Oxygenase A (PpoA)
Authors: Nadler André , Koch Christian , Brodhun Florian , Wehland Jan‐Dirk , Tittmann Kai , Feussner Ivo , Diederichsen Ulf
Published: March 2011

PpoA is a bifunctional enzyme that catalyzes the dioxygenation of unsaturated C18 fatty acids. The products of this reaction are termed psi factors and have been shown to play a crucial role in conferring a balance between sexual and asexual spore development as well as production of secondary metabolites in the fungus Aspergillus nidulans. Studies on the reaction mechanism revealed that PpoA uses two different heme domains to catalyze two subsequent reactions. Initially, the fatty acid substrate is dioxygenated at C8, yielding an 8‐hydroperoxy fatty acid at the N‐terminal domain. This reaction is catalyzed by a peroxidase/dioxygenase‐type domain that exhibits many similarities to prostaglandin H2 synthases and involves a stereospecific homolytic hydrogen abstraction from C8 of the substrate. The C terminus harbors a heme thiolate P450 domain in which rearrangement of the 8‐hydroperoxide to the final product, a 5,8‐dihydroxy fatty acid, takes place. To obtain further information about the intrinsic kinetics and reaction mechanism of PpoA, we synthesized C5‐dideutero‐ and C8‐dideutero‐oleic acid by a novel protocol that offers a straightforward synthesis without employing the toxic additive hexamethylphosphoramide (HMPA) during CC coupling reactions or mercury salts upon thioketal deprotection. These deuterated fatty acids were then employed for kinetic analysis under multiple‐turnover conditions. The results indicate that the hydrogen abstraction at C8 is the rate‐determining step of the overall reaction because we observed a KIE (VH/VD) of ∼33 at substrate saturation that suggests extensive nuclear tunneling contributions for hydrogen transfer. Deuteration of the substrate at C5, however, had little effect on VH/VD but resulted in a different product pattern presumably due to an altered lifetime and partitioning of a reaction intermediate.
Design, Synthesis and Characterization of a New Anionic Cell‐Penetrating Peptide: SAP(E)
Authors: Martín Irene , Teixidó Meritxell , Giralt Ernest
Published: March 2011

Cell‐penetrating peptides (CPPs) are powerful tools to transport cell‐impermeable cargoes into the cytoplasm without damaging the cell membrane. The vast majority of these peptides described to date share several features, among others, they are positively charged at physiological pH. In several cases a clear correlation between an increasing number of positive charges and internalization properties has been reported. Here, we describe what, to the best of our knowledge, is the first anionic CPP. This new compound SAP(E) internalizes into a range of cell lines with good efficiency and it shows low toxicity. We also report on the internalization mechanism. The discovery of this new class of CPP opens the way to the intracellular delivery of new molecular cargoes.
Potent and Selective Synthetic Modulators of a Quorum Sensing Repressor in Pseudomonas aeruginosa Identified from Second‐Generation Libraries of N‐Acylated L‐Homoserine Lactones
Authors: Mattmann Margrith E. , Shipway Patrick M. , Heth Nicole J. , Blackwell Helen E.
Published: March 2011

Bacteria can coordinate group behavior using chemical signals in a process called quorum sensing (QS). The QS system in the opportunistic pathogen Pseudomonas aeruginosa is largely governed by the LasR receptor and its cognate chemical signal, N‐(3‐oxo)‐dodecanoyl L‐homoserine lactone (OdDHL). LasR also appears to share this signal with an orphan LuxR‐type receptor in P. aeruginosa, termed QscR, which represses LasR activity. Non‐native molecules that modulate QscR would represent valuable tools to study the role of this novel QS repressor protein in P. aeruginosa. We performed a critical analysis of previously identified, non‐native N‐acylated L‐homoserine lactone (AHL) activators and inhibitors of QscR to determine a set of structure–activity relationships (SARs). Based on these SAR data, we designed, synthesized, and screened several second‐generation libraries of AHLs for new ligands that could target QscR. These studies revealed the most active AHL agonists and antagonists of QscR reported to date, with activities ranging from nanomolar to low micromolar in a QscR bacterial reporter strain. Several of these AHLs were highly selective for QscR over LasR and other LuxR‐type receptors. A small subset of the new QscR activators, however, were also found to inhibit LasR; this demonstrates the exciting potential for the synergistic modulation of these integral P. aeruginosa QS receptors by using a single synthetic compound.
Water‐Soluble IrIII N‐Heterocyclic Carbene Based Catalysts for the Reduction of CO2 to Formate by Transfer Hydrogenation and the Deuteration of Aryl Amines in Water
Authors: Azua Arturo , Sanz Sergio , Peris Eduardo
Published: March 2011

Two new water‐soluble [IrI2(AcO)(bis‐NHC)] complexes (NHC=N‐heterocyclic carbene) incorporating a sulfonate functionality have been synthesized. The two complexes have been tested in the reduction of CO2 with H2 and iPrOH, and their activity has been compared with similar species without the sulfonate moiety. In both reactions, the complex with the two abnormally bound NHCs shows the best catalytic efficiencies, due to the higher σ‐electron‐donor character of the ligand. Remarkably, the activities obtained for the reduction of CO2 under the transfer hydrogenation conditions are the best reported to date in terms of TON value (max. TON=2700). The two new complexes have also shown very good activity in the selective deuteration of arylamines, a process that is known to proceed through a chelate assisted N‐directed process.
Comparison and validation of CFD models in liquid–solid suspensions
Authors: Visuri Olli , Liiri Maret , Alopaeus Ville
Published: March 2011

A new simple method to validate CFD models in multiphase flows is presented. The experimental procedure used in this study is based on digital imaging and a simple algorithm to reduce the noise of an image. This method is inexpensive and easy to use and it can be applied to several liquid–solid systems where the liquid is transparent. The CFD modelling was done using a two‐fluid κ–ε model. Several drag correlations were tested in simulations with two impeller speeds and various particle sizes. The results were compared with experimental data. Comparison was also made with the just‐suspended speed correlation by Zwietering.
Explicit equations for laminar flow of herschel–bulkley fluids
Authors: Swamee Prabhata K. , Aggarwal Nitin
Published: March 2011

There are three typical problems encountered in pipe flows: unknown friction factor, unknown flow rate, and unknown diameter problems. A major problem in determining the solution to these flow problems occurs due to the implicit nature of the Darcy–Weisbach friction factor. Though explicit equations for flow of Newtonian fluids and Power Law fluids are available, no such usable equations exist for Herschel–Bulkley fluids. In this paper, explicit equations have been given for flow of Herschel–Bulkley fluids in the laminar regime.
A cell‐based screen for inhibitors of flagella‐driven motility in Chlamydomonas reveals a novel modulator of ciliary length and retrograde actin flow
Authors: Engel Benjamin D. , Ishikawa Hiroaki , Feldman Jessica L. , Wilson Christopher W. , Chuang Pao‐Tien , Snedecor June , Williams Janice , Sun Zhaoxia , Marshall Wallace F.
Published: March 2011

Cilia are motile and sensory organelles with critical roles in physiology. Ciliary defects can cause numerous human disease symptoms including polycystic kidneys, hydrocephalus, and retinal degeneration. Despite the importance of these organelles, their assembly and function is not fully understood. The unicellular green alga Chlamydomonas reinhardtii has many advantages as a model system for studies of ciliary assembly and function. Here we describe our initial efforts to build a chemical‐biology toolkit to augment the genetic tools available for studying cilia in this organism, with the goal of being able to reversibly perturb ciliary function on a rapid time‐scale compared to that available with traditional genetic methods. We screened a set of 5520 compounds from which we identified four candidate compounds with reproducible effects on flagella at nontoxic doses. Three of these compounds resulted in flagellar paralysis and one induced flagellar shortening in a reversible and dose‐dependent fashion, accompanied by a reduction in the speed of intraflagellar transport. This latter compound also reduced the length of cilia in mammalian cells, hence we named the compound “ciliabrevin” due to its ability to shorten cilia. This compound also robustly and reversibly inhibited microtubule movement and retrograde actin flow in Drosophila S2 cells. Ciliabrevin may prove especially useful for the study of retrograde actin flow at the leading edge of cells, as it slows the retrograde flow in a tunable dose‐dependent fashion until flow completely stops at high concentrations, and these effects are quickly reversed upon washout of the drug. © 2011 Wiley‐Liss, Inc.
Significant J‐shaped association between body mass index (BMI) and diabetic foot ulcers
Authors: Sohn Min‐Woong , Budiman‐Mak Elly , Lee Todd A. , Oh Elissa , Stuck Rodney M.
Published: March 2011

Background

Disagreement exists regarding the relationship between body weight and foot ulceration risk among diabetic persons.

Methods

We used a nested case‐control design to estimate the association between body mass index (BMI) and 1‐year and 5‐year foot ulceration risk. We obtained data on all diabetic patients < 60 years of age who were treated in the US Department of Veterans Affairs healthcare system in 2003. Patient characteristics and co‐morbidities were obtained at baseline. For each individual with an incident foot ulcer (case), up to four individuals were randomly selected who matched the case on age, sex, race, marital status, and calendar time.

Results

Crude 1‐year and 5‐year incidence rates were 1.35 and 6.22% after a mean follow‐up of 11.8 ± 1.2 months and 55.5 ± 12.8 months, respectively. Compared with individuals with BMI 25–29.9 kg/m2, those with BMI 40–44.9 kg/m2 and those with BMI ≥ 45 kg/m2 had 25% [adjusted odds ratio (AOR) = 1.25; 95% confidence interval (CI), 1–1.56] and 83% (AOR = 1.83; 95% CI, 1.44–2.32) higher 1‐year risk and 1.4 (AOR = 1.39; 95% CI, 1.26–1.54) and 2.1 (AOR = 2.08; 95% CI, 1.86–2.32) times higher 5‐year risk. BMI < 25 kg/m2 was associated with 30% higher risk at both 1 year (AOR = 1.28; 95% CI, 1.04–1.58) and 5 years (AOR = 1.27; 95% CI, 1.15–1.40).

Conclusions

Our data suggest a significant J‐shaped association between BMI and diabetic foot ulcers. Published 2011. This article is a US Government work and is in the public domain in the USA.
Rdh10 mutants deficient in limb field retinoic acid signaling exhibit normal limb patterning but display interdigital webbing
Authors: Cunningham Thomas J. , Chatzi Christina , Sandell Lisa L. , Trainor Paul A. , Duester Gregg
Published: March 2011

Retinoic acid (RA) is purported to be required for expression of genes controlling proximodistal (Meis2) or anteroposterior (Shh) limb patterning. Embryos lacking RDH10, the primary enzyme synthesizing retinaldehyde during mouse development, survive until E14.5 with stunted forelimbs but apparently normal hindlimbs. Using embryos carrying the RARE‐lacZ RA‐reporter transgene, we show that endogenous RA activity in Rdh10trex/trex mutants is detected in neuroectoderm but not limbs during initiation and patterning. Treatment of Rdh10 mutants with 25 nM RA restores RARE‐lacZ activity to limb mesoderm, validating RARE‐lacZ and verifying that RA is absent in mutant limbs. In Rdh10 mutants, hindlimbs exhibit normal Meis2/Shh expression and skeletal patterning, and although forelimbs are growth‐retarded their Meis2 expression remains normal. Later in development, Rdh10 mutants lack interdigital RA activity and accordingly fail to exhibit normal loss of interdigital mesenchyme. These findings demonstrate that RA is unnecessary for limb patterning but required later for interdigital tissue loss. Developmental Dynamics 240:1142–1150, 2011. © 2011 Wiley‐Liss, Inc.
Keeping up with the zone of polarizing activity: New roles for an old signaling center
Authors: Harfe Brian D.
Published: March 2011

The vertebrate limb is an excellent model organ system to investigate how signaling pathways interact. Over the last half‐century, experiments investigating patterning in the vertebrate limb have led directly to the discovery of many of the molecules and molecular pathways that are not only responsible for limb patterning but the patterning of many different organ systems. In the limb bud, the zone of polarizing activity (ZPA) has long been known to produce factor(s) that are essential for normal limb formation. Recently, one of these factors, Sonic Hedgehog (SHH) was shown to function not only in the limb bud mesenchyme but also in the ectoderm overlying the ZPA. This review discusses the role and potential implications hedgehog signaling in the limb bud ectoderm plays in patterning the vertebrate limb. Developmental Dynamics 240:915–919, 2011. © 2011 Wiley‐Liss, Inc.
Synthesis and Characterization of Nickel(II) Aminoalkoxides: Application to Molecular Precursors for MOCVD of Ni Thin Films
Authors: Yoo Seung Ho , Choi Hana , Kim Hyo‐Suk , Park Bo Keun , Lee Sun Sook , An Ki‐Seok , Lee Young Kuk , Chung Taek‐Mo , Kim Chang Gyoun
Published: March 2011

Novel single precursors for Ni, Ni(dmamp)2 (1), Ni(deamp)2 (2), and Ni(emamp)2 (3), were synthesized by the metathesis reaction between [Ni(NH3)6]Cl2 and two equiv. of Na(dmamp), Na(deamp), and Na(emamp), respectively. Complexes 1–3 have been characterized by IR, 1H NMR, and 13C NMR spectroscopies, and microanalytical data, as well as single‐crystal X‐ray diffraction studies. Through GC/MS analysis of the gaseous species generated by the decomposition of 1, a self‐reduction pathway to form metallic Ni was studied. By the metalorganic chemical vapor deposition of 1, metallic Ni hexagonal‐phase thin films were obtained at 250 °C and cubic‐phase thin films were obtained at 400 °C.
Synthesis and Theoretical Hirshfeld Analysis of a Supramolecular Heteropolyoxovanadate Architecture
Authors: Grabau Mathias , Forster Johannes , Heussner Kirsten , Streb Carsten
Published: March 2011

A supramolecular heteropolyoxovanadate structure has been synthesized and characterized using single‐crystal XRD, powder XRD and a range of spectroscopic methods. The new compound, [tBuNH(C2H4OH)2]4[H5P1V14O42]·12H2O (1) was obtained using a one‐pot strategy starting from a simple inorganic vanadium oxide precursor and an amphiphilic cation in acidic aqueous solution. The cluster anion [H5P1V14O42]4– is based on the well‐known Keggin structure but in addition features two capping vanadyl [V=O]3+ units. In the crystal lattice, the clusters are arranged in linear 1D chains where neighbouring clusters are directly linked by one hydrogen bond. In addition, the assembly is stabilized by lattice water molecules and organic counterions which aggregate to form hydrophobic cavities with diameters of 0.6 nm. In order to analyze the supramolecular interactions leading to the cluster formation, we have used a combination of traditional structural analysis, theoretical bond valence sum (BVS) calculations and computational Hirshfeld surface analyses which allow the rapid determination of short‐ and long‐range intermolecular contacts. The applicability of the Hirshfeld analysis tool for complex ionic compounds is evaluated and the advantages as well as the limitations of the method are discussed. The combination of these techniques allowed us to assess the dominating intermolecular interactions and showed that the crystal packing is not only controlled by electrostatic interactions, but also by distinctive sets of hydrogen bonds and hydrophobic interactions between adjacent organic counterions.
Determination of Binding Constants of Hydrogen‐Bonded Complexes by ITC, NMR CIS, and NMR Diffusion Experiments
Authors: Dethlefs Christiane , Eckelmann Jens , Kobarg Hauke , Weyrich Thomas , Brammer Stefan , Näther Christian , Lüning Ulrich
Published: March 2011

The host–guest complex formation between barbital and various acylaminopyridyl isophthalamides (Hamilton receptors) has been determined quantitatively. The syntheses of nine isophthalamides are described. Their structures differ in the substitution patterns on the central isophthalic unit, and the natures of the acyl residues. Ethylhexanoyl derivatives proved to be more soluble than pentanoyl amides. The association constants were determined by 1H NMR titrations monitoring chemically induced shifts (CIS values), by 1H NMR diffusion experiments, and by isothermal titration calorimetry (ITC), giving Kass values in chloroform at 298 K between 33 × 103 and 100 × 103 M–1.
Cooperative Catalytic Reactions Using Lewis Acids and Organocatalysts: Enantioselective Propargylic Alkylation of Propargylic Alcohols Bearing an Internal Alkyne with Aldehydes
Authors: Motoyama Kazuki , Ikeda Masahiro , Miyake Yoshihiro , Nishibayashi Yoshiaki
Published: March 2011

The enantioselective propargylic alkylation of propargylic alcohols bearing an internal alkyne moiety with aldehydes in the presence of a metal salt as the Lewis acid and an optically active secondary amine as the co‐catalyst has been found to give the corresponding propargylic alkylated products in high yields as a mixture of two diastereoisomers with high enantioselectivity.
A basic phenylalanine‐rich oligo‐peptide causes antibody cross‐reactivity
Authors: Luo Gangyue , Quan Guanghua , Guo Jinya , Zhang Haijiang , Li Sun , Wu Weidong , Nie Ling , Dong Yuliang , Wu Suhong , Zheng Guangni , Yang Jing , Xu Jie , Wang Weina
Published: March 2011

Glycolate oxidase (GO) and ribulose‐1,5‐bisphosphate carboxylase/oxygenase (RubisCO) are the two enzymes that serve key functions in the photorespiration and photosynthesis of plants. A 2 kDa highly basic phenylalanine‐rich oligo‐peptide (BOP) binds to the surface of acidic GO via ionic and hydrophobic interactions, forming the GO‐BOP complex (GC). Previously, RubisCO was thought to exist as a single species composed of a large (rbc L, 54 kDa) and a small subunit (rbc S, 14 kDa). Here we show for the first time, using 2‐DE, SDS‐PAGE, immunoassays and amino acid determination, that BOP also interacts with RubisCO and that many RubisCO‐BOP complexes (RCs), differing in pI, hydrophobicity and activity, coexist in green leaves. GCs, RCs and crude extract from green leaves analyzed by SDS‐PAGE Western blotting showed that BOP exists either in subunit‐BOP complexes (GO subunit‐BOP, rbc L‐BOP and rbc S‐BOP etc.), with a wide variation in the number and the position of BOPs bound to each subunit molecular, or alone without a binding partner. When rbc L‐BOP and rbc S‐BOP were assayed by SDS‐PAGE, BOP was dissociated from the subunit and it self‐assembled to form 37 different BOP polymers (basic phenylalanine‐rich protein) whose molecular weights (Mrs) ranged from 34.0 to 91.6 kDa, indicating that the Mr of BOP is about 2 kDa. Thus, the addition of BOP changes the Mr of the subunit‐BOP complexes so minimally that the rbc L and rbc S run at their predicted Mrs on SDS‐PAGE. In summary, the results described here demonstrate that the presence of BOP in complexes (both subunit‐BOP complex and protein‐BOP complex) can cause cross‐reactivity of antibodies against different proteins.
A novel capillary electrophoretic method for determining aliphatic aldehydes in food samples using 2‐thiobarbituric acid derivatization
Authors: Zhang Jun‐Bo , Li Meng‐Jie , Li Wen‐Li , Chu Qing‐Cui , Ye Jian‐Nong
Published: March 2011

A novel electrophoretic method for sensitive determination of nine aldehydes, including formaldehyde (C1), acetaldehyde (C2), propanal (C3), butanal (C4), pentanal (C5), hexanal (C6), glutaradehyde (Gla), 2,3‐butanedione (Bud) and methylgloxal (MGo) in food samples, has been developed based on CE with amperometric detection (CE‐AD). After being derivatized with an electroactive compound, 2‐thiobarbituric acid (TBA), these nine non‐electroactive aldehydes were converted to electroactive adducts, and therefore detectable by CE‐AD approach. Experimental conditions of derivatization and CE‐AD detection were optimized. The proposed method was validated according to International Conference on Harmonization (ICH) requirements, with recovery results ranging from 82.8 to 123.8%. Calibration plots of aliphatic aldehydes were linear (r2≥0.9901) in the concentration range from 0.083 to 15.0 mg/L. The LODs were between 0.008 and 0.074 mg/L. The proposed CE‐AD method provides a reliable and sensitive quantitative evaluation for non‐electroactive low‐molecular‐mass monoaldehydes and dialdehydes in real sample matrices by employing relatively simple and inexpensive instrument.
Rapid analysis of phosphoamino acids from phosvitin by near‐infrared cyanine 1‐(ε‐succinimydyl‐hexanoate)‐1′‐methyl‐3,3,3′,3′‐tetramethyl‐indocarbocyanine‐5,5′‐disulfonate potassium derivatization and polyacrylamide‐coated CE with LIF detection
Authors: Fu Ni‐Na , Wang Hong , Zhang Hua‐Shan
Published: March 2011

A polyacrylamide‐coated CE method with LIF detection was developed for analyzing three phosphoamino acids including phosphotyrosine (p‐Tyr), phosphothreonine (p‐Thr), and phosphoserine (p‐Ser). A near‐infrared dye, 1‐(ε‐succinimydyl‐hexanoate)‐1′‐methyl‐3,3,3′,3′‐tetramethyl‐indocarbocyanine‐5,5′‐disulfonate potassium (MeCy5‐OSu) was employed for derivatization of these phosphoamino acids. Results indicated that the complete baseline resolution of each phosphoamino acid was obtained within 6.1 min, using 10 mmol/L phosphate buffer (pH 4.0) containing 60 mmol/L SDS as running buffer. The highest derivatization efficiency was achieved in 0.2 mol/L borate buffer (pH 8.8) for 30 min at 30°C. Linearity of response was found in the range of 0.05–1 μmol/L. The correlation coefficients for these phosphoamino acids were from 0.9940 to 0.9976. The LODs for phosphotyrosine, phosphothreonine, and phosphoserine were about 6, 8, and 8 nmol/L, respectively. The proposed method has been successfully applied to the determination of phosphoamino acids in the hydrolysis sample of a phosphorylated phosvitin. Average recoveries for phosvitin sample were in the range of 94.0–98.0% and coefficients of variation ranged from 2.7 to 4.8%.
Study of binding constant of toll‐like receptor 4 and lipopolysaccharide using capillary zone electrophoresis
Authors: Fu Huiqing , Li Jimin , Meng Weiwei , Dong Runan , Dai Rongji , Deng Yulin
Published: March 2011

This short communication describes the interaction between toll‐like receptor 4 (TLR4) and lipopolysaccharide (LPS, its specific ligand) using analytical methods. Their interaction has been evidenced in many reports. Nevertheless, there are few reports focused on their binding constant. In this research, the interaction between TLR4 and LPS is investigated using mobility shift method by CZE. To optimize the electrophoresis conditions, the effecting factors, running buffer, sample concentration, injection duration, and operation voltage of electrophoretic on the mobility shift are studied in detail. Electrophoresis conditions were described as follows: borate buffer (pH 7.4, 20 mM), 5 s for 50 mbar pressure injection duration, and 13 kV of separation voltage in 41.5 cm fused silica capillary with 75 μm id and 375 μm od. The combination constant of TLR4 and LPS is calculated using Scatchard methods. The Scatchard liner correlation is y=−0.0165x+0.1456, binding constant is K=1.65×104 (g/mL)−1.
Residues of PBDEs in northeastern Pacific marine fish: Evidence for spatial and temporal trends
Authors: Ikonomou Michael G , Teas Howard J , Gerlach Robert , Higgs Dave , Addison Richard F
Published: March 2011

In the flesh (skinless fillet) of chinook, chum, coho, pink, and sockeye salmon (Oncorhynchus tshawytscha, O. keta, O. kisutch, O. gorbuscha, and O. nerka, respectively), sablefish (Anoplopoma fimbria) and walleye pollock (Theragra chalcogramma) from several sites in the northeast Pacific sampled between 2002 and 2008, tetra- and pentabrominated diphenyl ethers (BDEs) (BDE 47, 49, 99, and 100) dominated the congener distribution. Chinook and sablefish contained the highest concentrations, followed by sockeye, coho, and pink salmon, and pollock. In sockeye from the Bering Sea – Aleutians and from the Gulf of Alaska, total tri- to hepta-BDE concentrations fell significantly between 2002 and 2005; in sablefish from Gulf of Alaska, there was a steady but statistically nonsignificant decline in BDE concentrations between 2002 and 2008. Relative proportions of the main BDE congeners did not change appreciably over time, within species or location. All species except sockeye salmon showed a clear southeastward increase in BDE concentrations, implying an increasing gradient in general ecosystem contamination. In chinook, coho, and sablefish, especially, the southeastward trend in increasing total concentrations was associated with increasing proportions of BDEs 47 and 100. Chinook returning to western North American natal streams appeared to accumulate most of their PBDE burden towards the end of their migration. Fish from more northern sampling sites often had higher proportions of more highly brominated congeners than those from more southern sites, perhaps reflecting contamination from Asian sources where higher-brominated commercial PBDE formulations are used. In sablefish and pollock, the relative proportions of BDEs 99 and 47 varied inversely in almost a 1:1 ratio, implying debromination of BDE 99 to 47. Environ. Toxicol. Chem. 2011; 30:1261–1271. © 2011 SETAC
Approach for an integral power transformer reliability model
Authors: van Schijndel A. , Wouters P.A.A.F. , Steennis E.F. , Wetzer J.M.
Published: March 2011

In electrical power transmission and distribution networks power transformers represent a crucial group of assets both in terms of reliability and investments. In order to safeguard the required quality at acceptable costs, decisions must be based on a reliable forecast of future behaviour. The aim of the present study is to develop an integral transformer lifetime model which involves degradation mechanisms for most relevant subsystems, applicable to individual power transformers and transformer populations. In this paper, we present a predictive model for power transformer reliability which involves three essential ingredients: failure statistics, physical understanding of the degradation process, and actual knowledge of the present condition. The model is based on evaluation of existing literature and past experience on degradation mechanisms, failure modes and diagnostic techniques. The model is illustrated for integral reliability of three transformer failure modes, related to the degradation of the transformer winding insulation, of bushings and of tap‐changers. Copyright © 2011 John Wiley & Sons, Ltd.
Application of ordinal optimization on reliability centered maintenance of distribution system
Authors: Park Geun‐Pyo , Yoon Yong T.
Published: March 2011

The problem of distribution system maintenance has a combinatorial explosion of choices. It may not be worthwhile to solve this problem using the analytical method that require too much time and cost. Ordinal optimization is a prime candidate of stochastic optimization problem. Ordinal optimization is used to quickly narrow the search space and find a good enough solution with reasonable confidence. This paper proposes the reliability centered maintenance model of distribution systems, and the solution of this problem through the application of ordinal optimization. A numerical examples are performed to illustrate the efficiency of the proposed ordinal optimization and to find a maintenance strategy of distribution systems. Copyright © 2011 John Wiley & Sons, Ltd.
The majority of infiltrating CD8 T lymphocytes in multiple sclerosis lesions is insensitive to enhanced PD‐L1 levels on CNS cells
Authors: Pittet Camille L. , Newcombe Jia , Antel Jack P. , Arbour Nathalie
Published: March 2011

Central nervous system (CNS) cells locally modulate immune responses using numerous molecules that are not fully elucidated. Engagement of programmed death‐1 (PD‐1), expressed on activated T cells, by its ligands (PD‐L1 or PD‐L2) suppresses T‐cell responses. Enhanced CNS PD‐1 and PD‐L1 expression has been documented in inflammatory murine models; however, human CNS data are still incomplete. We determined that human primary cultures of astrocytes, microglia, oligodendrocytes, or neurons expressed low or undetectable PD‐L1 under basal conditions, but inflammatory cytokines significantly induced such expression, especially on astrocytes and microglia. Blocking PD‐L1 expression in astrocytes using specific siRNA led to significantly increased CD8 T‐cell responses (proliferation, cytokines, lytic enzyme). Thus, our results establish that inflamed human glial cells can express sufficient and functional PD‐L1 to inhibit CD8 T cell responses. Extensive immunohistochemical analysis of postmortem brain tissues demonstrated a significantly greater PD‐L1 expression in multiple sclerosis (MS) lesions compared with control tissues, which colocalized with astrocyte or microglia/macrophage cell markers. However, more than half of infiltrating CD8 T lymphocytes in MS lesions did not express PD‐1, the cognate receptor. Thus, our results demonstrate that inflamed human CNS cells such as in MS lesions express significantly elevated PD‐L1, providing a means to reduce CD8 T cell responses, but most of these infiltrating immune cells are devoid of PD‐1 and thus insensitive to PD‐L1/L2. Strategies aimed at inducing PD‐1 on deleterious activated human CD8 T cells that are devoid of this receptor could provide therapeutic benefits since PD‐L1 is already increased in the target organ. © 2011 Wiley‐Liss, Inc.
Estimating the net contribution of interleukin-28B variation to spontaneous hepatitis C virus clearance
Authors: di Iulio Julia , Ciuffi Angela , Fitzmaurice Karen , Kelleher Dermot , Rotger Margalida , Fellay Jacques , Martinez Raquel , Pulit Sara , Furrer Hansjakob , Günthard Huldrych F. , Battegay Manuel , Bernasconi Enos , Schmid Patrick , Hirschel Bernard , Barnes Eleanor , Klenerman Paul , Telenti Amalio , Rauch Andri
Published: March 2011

The identification of associations between interleukin-28B (

IL-28B

) variants and the spontaneous clearance of hepatitis C virus (HCV) raises the issues of causality and the net contribution of host genetics to the trait. To estimate more precisely the net effect of

IL-28B

genetic variation on HCV clearance, we optimized genotyping and compared the host contributions in multiple- and single-source cohorts to control for viral and demographic effects. The analysis included individuals with chronic or spontaneously cleared HCV infections from a multiple-source cohort (n = 389) and a single-source cohort (n = 71). We performed detailed genotyping in the coding region of

IL-28B

and searched for copy number variations to identify the genetic variant or haplotype carrying the strongest association with viral clearance. This analysis was used to compare the effects of

IL-28B

variation in the two cohorts. Haplotypes characterized by carriage of the major alleles at

IL-28B

single-nucleotide polymorphisms (SNPs) were highly overrepresented in individuals with spontaneous clearance versus those with chronic HCV infections (66.1% versus 38.6%,

P

= 6 × 10−9). The odds ratios for clearance were 2.1 [95% confidence interval (CI) = 1.6–3.0] and 3.9 (95% CI = 1.5–10.2) in the multiple- and single-source cohorts, respectively. Protective haplotypes were in perfect linkage (

r

2 = 1.0) with a nonsynonymous coding variant (rs8103142). Copy number variants were not detected.

Conclusion:

We identified

IL-28B

haplotypes highly predictive of spontaneous HCV clearance. The high linkage disequilibrium between

IL-28B

SNPs indicates that association studies need to be complemented by functional experiments to identify single causal variants. The point estimate for the genetic effect was higher in the single-source cohort, which was used to effectively control for viral diversity, sex, and coinfections and, therefore, offered a precise estimate of the net host genetic contribution. (Hepatology 2011;)
Higher busulfan dose intensity does not improve outcomes of patients undergoing allogeneic haematopoietic cell transplantation following fludarabine, busulfan‐based reduced toxicity conditioning
Authors: Hamadani Mehdi , Craig Michael , Phillips Gary S. , Abraham Jame , Tse William , Cumpston Aaron , Gibson Laura , Remick Scot C. , Bunner Pamela , Leadmon Sonia , Elder Patrick , Hofmeister Craig , Penza Sam , Efebera Yvonne , Andritsos Leslie , Garzon Ramiro , Benson Don M. , Blum William , Devine Steven M.
Published: March 2011

We evaluated the impact of busulfan dose intensity in patients undergoing reduced toxicity/intensity conditioning allogeneic transplantation in a multicenter retrospective study of 112 consecutive patients. Seventy‐five patients were conditioned with busulfan (0.8 mg/kg/dose IV × 8 doses), fludarabine (30 mg/m2/day, days −7 to −3), and 6 mg/kg of ATG [reduced intensity conditioning (RIC) group], while 37 patients received a more‐intense conditioning with busulfan (130 mg/m2/day IV, days −6 to −3), fludarabine (40 mg/m2/day, days −6 to −3) and 6 mg/kg of ATG [reduced toxicity conditioning (RTC) group]. At baseline both groups were matched for median age, unrelated donor allografts, and human leukocyte antigen‐mismatched allografts. More patients in RIC group had high‐risk disease, and higher median comorbidity index. There were no graft rejections. Median time to neutrophil (17 days vs. 15 days; p = 0.003) and platelet engraftment (16 days vs. 11 days; p < 0.001) was significantly longer in the RIC group. RTC group had significantly more bacterial (62.2% vs. 32%; p = 0.004) and fungal infections (13.5% vs. 1.3% p = 0.01). For RIC and RTC groups rates of grades II–IV acute GVHD (34% vs. 40%; p‐value = 0.54), and chronic GVHD (45% vs. 57%; p‐value = 0.30) were not significantly different. In similar order at 1 year the cumulative‐incidence of non‐relapse mortality (NRM; 12% vs. 21%; p‐value = 0.21) and relapse rates (38% vs. 39%; p = 0.96) were not significantly different. Patients in RIC and RTC groups had similar 1‐year overall survival (61% vs. 50%, p = 0.11) and progression‐free survival (50% vs. 36%, p‐value = 0.39). Our data suggest that the merits of higher busulfan dose intensity in the context of fludarabine/busulfan‐based RTC may be offset by higher early morbidity. Copyright © 2011 John Wiley & Sons, Ltd.