bluuebunny/crossref_metadata_2025 huggingface dataset:
DNA‐Assemblierung mittels Affinitätsbindung für die ultraempfindliche Proteindetektion
Authors: Zhang Hongquan , Li Feng , Dever Brittany , Wang Chuan , Li Xing‐Fang , Le X. Chris
Published: August 2013

Jüngste Fortschritte auf dem Gebiet der DNA‐Assemblierung und der Affinitätsbindung haben zu aufregenden neuen Entwicklungen bei Nanosensoren und ultraempfindlichen Nachweismethoden für spezifische Proteine geführt.1–6 Diese Sensoren und Nachweissysteme haben drei attraktive Eigenschaften gemeinsam:1, 4, 7 1) Der Proteinnachweis gelingt mittelbar durch die Detektion amplifizierter DNA, wodurch die Empfindlichkeit drastisch erhöht wird. 2) Die Zusammenlagerung der DNA wird durch Affinitätsbindung von zwei oder mehr “Sonden” zu einem einzelnen Analytmolekül ausgelöst, was eine erhöhte Spezifität bedingt. 3) Der Nachweis erfolgt in Lösung ohne die Notwendigkeit einer vorherigen Abtrennung, was die Methodik für patientennahe Anwendungen attraktiv erscheinen lässt. Wir legen in diesem Kurzaufsatz das Prinzip dar, nach dem die Zusammenlagerung von DNA‐Molekülen mittels Affinitätsbindung erfolgt. Dabei stellen wir neuartige Anwendungen für den Nachweis von Proteinen beispielhaft heraus.
Flame retardancy and water resistance of novel intumescent flame‐retardant oil‐filled styrene–ethylene–butadiene–styrene block copolymer/polypropylene composites
Authors: Zang Yuansheng , Li Bin , Xu Miaojun
Published: August 2013

A novel halogen‐free flame‐retardant composite consisting of an intumescent flame retardant (IFR), oil‐filled styrene–ethylene–butadiene–styrene block copolymer (O‐SEBS), and polypropylene (PP) was studied. On the basis of UL‐94 ratings and limiting oxygen index (LOI) data, the IFRs consisted of a charring–foaming agent, ammonium polyphosphate, and SiO2showed very effective flame retardancy and good water resistance in the IFR O‐SEBS/PP composite. When the loading of IFR was only 28 wt %, the IFR–O‐SEBS/PP composite could still attain a UL‐94 V‐0 (1.6 mm) rating, and its LOI value remained at 29.8% after a water treatment at 70°C for 168 h. Thermogravimetric analysis data indicated that the IFR effectively enhanced the temperature of the main thermal degradation peak of the IFR–O‐SEBS/PP composites because of the formation of abundant char residue. The flammability parameters of the composites obtained from cone calorimetry testing demonstrated that water treatment almost did not affect the flammability behavior of the composite. The morphological structures of the char residue and fractured surfaces of the composites were not affected by the water treatment. This was attributed to a small quantity of IFR extracted from the composite. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2014,131, 39575.
Fabrication and properties of nano indium tin oxide/wool keratin composites
Authors: Li Rong , He Jinsong , Wen Feng , Wang Dong
Published: August 2013

A functional keratin/indium tin oxide (ITO) composite was prepared by a route involving an ionic liquid dissolving process and a wet‐chemical codeposition technique. The crystal structure and morphology of ITO were investigated by X‐ray diffraction and transmission electron microscopy, respectively. The factors influencing the crystal structure and the size of the ITO were investigated in detail. The optimal In/Sn ratio, reaction temperature, and pH value were found to be 10:1, 70°C, and 7, respectively. The sheet resistance of the composite reached 0.39 kΩ/□. In addition, the composite films possessed a perfect UV protection ability with a UV protection factor of up to 43.78. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39641.
Synthesis, characterization, and flocculation performance of a sulfonated polytriazine
Authors: Tang Bingtao , Liu Hong , Cui Zhihua , Zhang Shufen
Published: August 2013

A novel sulfonated polytriazine (SP) is synthesized by the condensation polymerization reaction of 2‐(4,6‐dichloro‐1,3,5‐triazin‐2‐ylamino)benzene‐1,4‐disulfonic acid (Compound I) and 1,4‐diaminobenzene. The structure of SP is characterized by FTIR spectroscopy, 1H‐NMR, and gel permeation chromatography (GPC). The flocculation performances for the cationic dyes are evaluated. The experimental results show that SP can efficiently remove the color of wastewater containing cationic dyes. The rates of color removal from C.I. Basic red 18 and C.I. Basic blue 9 reach as high as 99.6% and 98.5%, respectively. The synthesized SP shows high adsorption capacities of 1719 and 1988 mg/g for C.I. Basic blue 9 and C.I. Basic red 18, respectively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39669.
Investigation of mechanical properties of alumina nanoparticle‐loaded hybrid glass/carbon‐fiber‐reinforced epoxy composites
Authors: Mohanty Akash , Srivastava Vijay Kumar , Sastry Pulya Umamaheswara
Published: August 2013

This research work investigates the tensile strength and elastic modulus of the alumina nanoparticles, glass fiber, and carbon fiber reinforced epoxy composites. The first type composites were made by adding 1–5 wt % (in the interval of 1%) of alumina to the epoxy matrix, whereas the second and third categories of composites were made by adding 1–5 wt % short glass, carbon fibers to the matrix. A fourth type of composite has also been synthesized by incorporating both alumina particles (2 wt %) and fibers to the epoxy. Results showed that the longitudinal modulus has significantly improved because of the filler additions. Both tensile strength and modulus are further better for hybrid composites consisting both alumina particles and glass fibers or carbon fibers. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39749.
Improvement of adhesion and continuity of polypyrrole thin films through surface modification of hydrophobic substrates
Authors: Gupta Namita Dutta , Das Swati , Das Nirmalya Sankar , Banerjee Diptonil , Sarkar Debabrata , Chattopadhyay Kalyan Kumar
Published: August 2013

Conducting polymer polypyrrole is reported to have a poor adhesion to substrate which limits its applicability as thin films. In this article, we report synthesis of well‐formed and continuous film of polypyrrole through treatment of hydrophobic substrates. However, in place of the widely used organosilanes, the substrates were simply treated with surfactant cetyl trimethylammonium bromide (CTAB) prior to vapor phase polymerization under controlled environment. Polypyrrole films formed on CTAB pretreated substrates were found to have improved adhesion and continuity compared to the films formed on untreated substrates. The improved adhesion results in better electronic properties as seen during Electron field emission studies. Based on contact angle analysis, we propose that CTAB molecules act as anchoring agents for the oxidant layer on the substrate and hence assist in the deposition of a more continuous polypyrrole film. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39771.
Acrylamide‐b‐N‐isopropylacrylamide block copolymers: Synthesis by atomic transfer radical polymerization in water and the effect of the hydrophilic–hydrophobic ratio on the solution properties
Authors: Wever Diego Armando Z. , Ramalho Graham , Picchioni Francesco , Broekhuis Antonius Augustinus
Published: August 2013

A series of block copolymers of acrylamide and N‐isopropylacrylamide (NIPAM) characterized by different ratios between the length of the two blocks have been prepared through atomic transfer radical polymerization in water at room temperature. The solution properties of the block copolymers were correlated to their chemical structure. The effect of the hydrophilic/hydrophobic balance on the critical micelle concentration (CMC) was investigated. The CMC increases at higher values for the solubility parameter, thus indicating a clear relationship between these two variables. In addition, the solution rheology (in water) of the block copolymers was studied to identify the effect of the chemical structure on the thermo‐responsiveness of the solutions. An increase in the length of the PNIPAM block leads to a more pronounced increase in the solution viscosity. This is discussed in the general frame of hydrophobic interactions strength. The prepared polymers are in principle suitable for applications in many fields, particularly in enhanced oil recovery. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39785.
Synthesis and swelling behavior of pH‐responsive polyurethane/poly[2‐(diethylamino)ethyl methacrylate] hybrid materials
Authors: Pardini Francisco M. , Amalvy Javier I.
Published: August 2013

Polyurethane (PU)/poly[2‐(diethylamino)ethyl methacrylate] hybrids, having a chemical bond between the PU and acrylic moieties and with different compositions, were prepared by the dispersion polymerization of 2‐(diethylamino)ethyl methacrylate (DEA) in the presence of preformed PU chains with polymerizable terminal vinyl groups. The PU dispersion was synthesized according to a prepolymer mixing process by the polyaddition of isophorone diisocyanate, poly(propylene glycol), 2‐hydroxyethyl methacrylate, and dimethylol propionic acid (DMPA). Then, it was dispersed in water by the prior neutralization of the carboxylic acid groups of DMPA with triethylamine, chain‐extended with ethylenediamine. The effect of the DEA content on the swelling properties (water uptake and dynamic swelling degree) at different pHs and at 37°C was determined. The samples were also characterized by Fourier transform infrared spectroscopy and modulated differential scanning calorimetry. The experimental results indicate a higher water uptake when the DEA content was increased on the hybrid materials and a significant change in the kinetics of swelling at pH 4 compared to those at pH 7. The water content of the hydrogels depended on the DEA content, and it was inversely proportional to the pH value. The pure PU film did not show important changes over the pH range examined in this study. The synthesized hybrids were useful as drug‐delivery, pH‐sensitive matrices. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39799.
Measurement and numerical prediction of fiber‐reinforced thermoplastics' thermal conductivity in injection molded parts
Authors: Feliciani Claudio , Takai Yoshihiro
Published: August 2013

Recent improvements in injection molding numerical simulation software have led to the possibility of computing fiber orientation in fiber reinforced materials during and at the end of the injection molding process. However, mechanical, thermal, and electrical properties of fiber reinforced materials are still largely measured experimentally. While theoretical models that consider fiber orientation for the prediction of those properties exist, estimating them numerically has not yet been practical. In the present study, two different models are used to estimate the thermal conductivity of fiber reinforced thermoplastics (FRT) using fiber orientation obtained by injection molding numerical simulation software. Experimental data were obtained by measuring fiber orientation in injection molded samples' micrographs by image processing methods. The results were then compared with the numerically obtained prediction and good agreement between numerical and experimental fiber orientation was found. Thermal conductivity for the same samples was computed by applying two different FRT thermal conductivity models using numerically obtained fiber orientation. In the case of thermal conductivity, predicted results were consistent with experimental data measurements, showing the validity of the models. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39811.
Mechanical properties of recycled kenaf/polyethylene terephthalate (PET) fiber reinforced polyoxymethylene (POM) hybrid composite
Authors: Dan‐mallam Yakubu , Abdullah Mohamad Zaki , Yusoff Puteri Sri Melor Megat
Published: August 2013

Environmental concerns have attracted researchers to study the recycling of composite materials and thermoplastics due to the desire not to waste materials and reduce disposal of scraps that may eventually pollute the environment. The main objective of this article is to study the effect of recycling on the mechanical properties of kenaf fiber/PET reinforced POM hybrid composite. The virgin hybrid composite was produced by compression molding and later subjected to mechanical testing. The scraps obtained after the mechanical testing were shredded, granulated and subjected to compression molding to produce samples for mechanical testing. Tensile strength of 27 MPa was obtained and (after second recycling process) which is lower compared to 73.8 MPa obtained for the virgin hybrid composite. There was a significant increase in flexural modulus (4.7 GPa) compared to the virgin hybrid composite. The impact strength dropped to 4.3 J cm−1 as against 10.5 J cm−1 for the virgin hybrid composite. The results of thermal degradation showed about 80% weight loss for kenaf fiber between 300 and 350°C. The weight loss may be due to the degradation of cellulose and hemicellulose content of the fiber. The percentage water absorption of the recycled composite dropped by about 80% compared to the virgin hybrid composite. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39831.
ALLOCATION OF CYSTEINE FOR GLUTATHIONE PRODUCTION IN CATERPILLARS WITH DIFFERENT ANTIOXIDANT DEFENSE STRATEGIES: A COMPARISON OF Lymantria dispar AND Malacosoma disstria
Authors: Barbehenn Raymond V. , Kochmanski Joseph , Menachem Brandon , Poirier Lisa M.
Published: August 2013

Sulfur amino acids [cysteine (Cys) and methionine (Met)] play two major roles during animal development: protein synthesis for growth and glutathione synthesis for defense. For caterpillars, the levels of sulfur amino acids found in foliar protein can be especially low relative to their nutritional needs. Previous work has measured concentrations of glutathione (GSH; containing Cys) in specific animal tissues, but has not examined whole‐body levels to ascertain the costliness of this defense in terms of Cys allocation. This study examined whether the production of GSH varies between species and within individuals in accordance with an insect's need for antioxidant defense. Secondly, we quantified the allocation of total Cys (peptide‐bound plus free Cys) to GSH in caterpillars as an estimate of its cost. Two contrasting species were compared: Lymantria dispar (Lymantriidae), a species that is highly defended, and Malacosoma disstria (Lasiocampidae), a species that is less defended. As expected, GSH levels were significantly higher in L. dispar than in M. disstria. Consistent with the function of the midgut as a first line of defense against ingested toxins, GSH levels were significantly higher in these tissues than in the whole bodies of both species. A major finding in this study was that a large fraction of total Cys is used to produce GSH: GSH in the midguts of L. dispar and M. disstria contained 23 and 21%, respectively, of the total Cys in these tissues, and the GSH in their remaining body tissues contained 19 and 17% of the total Cys in these tissues. Levels of total Cys in caterpillar tissues followed the same pattern of distribution as did GSH, producing a strong association between GSH and total Cys (R2 = 0.794). We conclude that GSH is a costly defense, especially in generalist tree‐feeding species such as L. dispar. These results further suggest that the large allocation of Cys to GSH in highly defended species might produce a tradeoff by limiting the amount of Cys available for rapid growth.
The missing teleconnection between the North Atlantic and the Sahel precipitation in CFSv2
Authors: Barandiaran Daniel , Wang Shih‐Yu
Published: August 2013

This study presents new findings on the link between interannual variabilities of atmospheric circulations over the North Atlantic and precipitation over the African Sahel (PS). Our analysis shows a meridionally stratified circulation wave train resembling the East Atlantic (EA) mode, apparently connected to PS through Rossby wave dispersion in the middle troposphere originating from the North Atlantic. However, the Climate Forecast System version 2 fails to depict the EA and its PS impact. Because the EA explains 29% of variance of PS, this portion of PS variability is either missing in the seasonal forecast, or being made up by an alternative process.
Studies on the interaction between vincamine and human serum albumin: a spectroscopic approach
Authors: Pu Hanlin , Jiang Hua , Chen Rongrong , Wang Hongcui
Published: August 2013

The interaction between vincamine (VCM) and human serum albumin (HSA) has been studied using a fluorescence quenching technique in combination with UV/vis absorption spectroscopy, Fourier transform infrared (FT–IR) spectroscopy, circular dichroism (CD) spectroscopy and molecular modeling under conditions similar to human physiological conditions. VCM effectively quenched the intrinsic fluorescence of HSA via static quenching. The binding constants were calculated from the fluorescence data. Thermodynamic analysis by Van't Hoff equation revealed enthalpy change (ΔH) and entropy change (ΔS) were −4.57 kJ/mol and 76.26 J/mol/K, respectively, which indicated that the binding process was spontaneous and the hydrophobic interaction was the predominant force. The distance r between the donor (HSA) and acceptor (VCM) was obtained according to the Förster's theory of non‐radiative energy transfer and found to be 4.41 nm. Metal ions, viz., Na+, K+, Li+, Ni2+, Ca2+, Zn2+ and Al3+ were found to influence binding of the drug to protein. The 3D fluorescence, FT–IR and CD spectral results revealed changes in the secondary structure of the protein upon interaction with VCM. Furthermore, molecular modeling indicated that VCM could bind to the subdomain IIA (site I) of HSA. Copyright © 2013 John Wiley & Sons, Ltd.
Different tocopherol isoforms vary in capacity to scavenge free radicals, prevent inflammatory response, and induce apoptosis in both adult‐ and fetal‐derived intestinal epithelial cells
Authors: Elisia Ingrid , Kitts David D.
Published: August 2013

Gamma‐tocopherol (γ‐Toc) and δ‐Toc are two vitamin E isoforms for which biological activities are not well established, yet these isoforms are present in many different sources of vegetable oils and, therefore, contribute significantly to the total dietary intake of vitamin E. Infant formula also contains relatively high amounts of γ‐Toc and δ‐Toc, compared with that found in human milk. The efficacy of γ‐Toc and δ‐Toc to modulate cellular events that include oxidative stress, inflammatory response, and apoptosis‐mediated cytotoxicity, relative to α‐Toc, was determined using differentiated Caco‐2 and primary FHs 74 Int cells intestinal epithelial cell lines. Antioxidant capacity of Toc‐isoforms followed the order of δ‐Toc > γ‐Toc > α‐Toc against peroxyl radical‐induced membrane oxidation in both Caco‐2 and FHs 74 Int cells, respectively. The different Toc‐isoforms suppressed inflammatory response in interferon (IFN) γ/phorbol myristate acetate (PMA)‐induced Caco‐2 adult‐derived intestinal epithelial cells, but exacerbated both IL8 and PGE2 secretion in fetal‐derived FHs 74 Int intestinal epithelial cells. Lastly, Toc exhibited an isoform‐dependent apoptosis‐mediated cytotoxicity, whereby δ‐Toc elicited the greatest apoptosis followed by γ‐Toc, whereas α‐Toc was not cytotoxic. Cellular uptake of non‐α‐Toc isoforms were greater (P < 0.05) than that observed for α‐Toc in both intestinal epithelial cell lines which in part explains the superior bioactive function observed for both γ‐Toc and δ‐Toc, compared with α‐Toc. We conclude that the non‐α‐Toc isoforms of vitamin E have distinct roles that influence oxidative stress and inflammatory responses in both adult and fetal‐derived intestinal epithelial cell lines. © 2013 BioFactors, 39(6):663–671, 2013
Two‐dimensional liquid chromatography for direct chiral separations: a review
Authors: León‐González María Eugenia , Rosales‐Conrado Noelia , Pérez‐Arribas Luis Vicente , Guillén‐Casla Vanesa
Published: August 2013

Separation of enantiomers remains a challenge owing to their identical physical and chemical properties in an achiral environment, and research on specialized separation techniques such as multidimensional achiral–chiral liquid chromatography continues to resolve individual enantiomers in complex samples. Recent advances in application of multidimensional liquid chromatography applied to chiral analysis are reviewed. For this reason, benefits of achiral–chiral coupling are shown, with emphasis in applications on biological and pharmaceutical fields as well as pesticide analysis. A description of standard instrumental setup in both heart‐cut and comprehensive multidimensional liquid chromatography is shown. The most broadly used chiral stationary phases for multidimensional liquid chromatography are summarized. An extensive overview of different interface designs applied to complex samples is presented. Copyright © 2013 John Wiley & Sons, Ltd.
The Antimicrobial Activity of Sub3 is Dependent on Membrane Binding and Cell‐Penetrating Ability
Authors: Torcato Inês M. , Huang Yen‐Hua , Franquelim Henri G. , Gaspar Diana D. , Craik David J. , Castanho Miguel A. R. B. , Henriques Sónia Troeira
Published: August 2013

Because of their high activity against microorganisms and low cytotoxicity, cationic antimicrobial peptides (AMPs) have been explored as the next generation of antibiotics. Although they have common structural features, the modes of action of AMPs are extensively debated, and a single mechanism does not explain the activity of all AMPs reported so far. Here we investigated the mechanism of action of Sub3, an AMP previously designed and optimised from high‐throughput screening with bactenecin as the template. Sub3 has potent activity against Gram‐negative and Gram‐positive bacteria as well as against fungi, but its mechanism of action has remained elusive. By using AFM imaging, ζ potential, flow cytometry and fluorescence methodologies with model membranes and bacterial cells, we found that, although the mechanism of action involves membrane targeting, Sub3 internalises inside bacteria at lethal concentrations without permeabilising the membrane, thus suggesting that its antimicrobial activity might involve both the membrane and intracellular targets. In addition, we found that Sub3 can be internalised into human cells without being toxic. As some bacteria are able to survive intracellularly and consequently evade host defences and antibiotic treatment, our findings suggest that Sub3 could be useful as an intracellular antimicrobial agent for infections that are notoriously difficult to treat.
Carbon Dioxide Reduction Catalyzed by Dinuclear Ruthenium Polypyridyl Complexes
Authors: Ono Takashi , Planas Nora , Miró Pere , Ertem Mehmed Z. , Escudero‐Adán Eduardo C. , Benet‐Buchholz Jordi , Gagliardi Laura , Cramer Christopher J. , Llobet Antoni
Published: August 2013

Dinuclear ruthenium complexes [(Ru(bid))2(μ‐bpp)(μ‐OAc)] and [(Ru(trpy))2(μ‐bpp)(μ‐X)]2+ [X=Cl−, OAc−, and OCHO−; bpp=3,5‐bis(2‐pyridyl)pyrazolato; bid−=(1Z,3Z)‐1,3‐bis(pyridin‐2‐ylmethylene)isoindolin‐2‐ide; trpy=2,2':6',2“‐terpyridine] were tested as catalysts for the hydrogenative reduction of carbon dioxide in the solvent 2,2,2‐trifluoroethanol in the presence of excess amine (triethylamine). Significant amounts of formic acid were produced by these catalysts, and a kinetic analysis based on initial rate constants was performed. These catalytic systems were investigated by using DFT calculations to elucidate the hydrogenative reduction mechanism. The results are compared with those obtained with previously reported mononuclear catalyst counterparts.
Dual pH‐ and Temperature‐Responsive Metallosupramolecular Block Copolymers with Tunable Critical Micelle Temperature by Modulation of the Self‐Assembly of NIR‐Emissive Alkynylplatinum(II) Complexes Induced by Changes in Hydrophilicity and Electrostatic Effects
Authors: Chung Clive Yik‐Sham , Yam Vivian Wing‐Wah
Published: August 2013

Terpyridylplatinum(II)‐based metallosupramolecular triblock copolymers with hydrophilic alkynyl ligands have been synthesised and characterised. As a result of the intrinsic properties of Pluronics, reversible temperature‐induced micellisation occurred at high temperature leading to aggregation of the platinum(II) complex moieties through Pt⋅⋅⋅Pt and π–π interactions, resulting in significant UV/Vis absorption and near‐infrared (NIR) emission spectral changes. The critical micelle temperatures of the complexes were found to vary from 21 to 30 °C due to differences in the hydrophilicity of the alkynyl ligands and the electrostatic repulsions between the positively charged platinum(II) complex moieties. One of the complexes with pH‐responsive CH2NMe2 groups on the alkynyl ligand was found to show NIR emission that is sensitive to both pH and temperature. Such dual‐responsive behaviour has been ascribed to the modulation of the self‐assembly of the complex moieties by temperature‐induced micellisation and the changes in the hydrophilicity as well as electrostatic interactions upon protonation/deprotonation of the CH2NMe2 groups on the alkynyl ligand.
Synthesis of Shape‐Persistent Macrocycles with Three 1,8‐Diazaanthracene Units and Their Packing in the Single Crystal
Authors: Li Ming , Klärner Frank‐Gerrit , Sakamoto Junji , Schlüter A. Dieter
Published: August 2013

The synthesis of four shape‐persistent macrocycles with three 1,8‐diazaanthracene units each is reported (2,3 a–3 c). For two of them single crystals could be obtained and the structures in the crystal be solved. The structures reveal that macrocycle 2 self‐dimerizes in the solid state; surprisingly it also forms a stable dimer in solution. The reason for this is seen in unusually efficient dispersion interactions as a consequence of the large contact areas in the dimer. All macrocycles are assessed as to their applicability in lateral polymerizations in the single crystal as well as in solution.
In‐Situ Spin Labeling of His‐Tagged Proteins: Distance Measurements under In‐Cell Conditions
Authors: Baldauf Christoph , Schulze Katrin , Lueders Petra , Bordignon Enrica , Tampé Robert
Published: August 2013

New spin labeling strategies have immense potential in studying protein structure and dynamics under physiological conditions with electron paramagnetic resonance (EPR) spectroscopy. Here, a new spin‐labeled chemical recognition unit for switchable and concomitantly high affinity binding to His‐tagged proteins was synthesized. In combination with an orthogonal site‐directed spin label, this novel spin probe, Proxyl‐trisNTA (P‐trisNTA) allows the extraction of structural constraints within proteins and macromolecular complexes by EPR. By using the multisubunit maltose import system of E. coli: 1) the topology of the substrate‐binding protein, 2) its substrate‐dependent conformational change, and 3) the formation of the membrane multiprotein complex can be extracted. Notably, the same distance information was retrieved both in vitro and in situ allowing for site‐specific spin labeling in cell lysates under in‐cell conditions. This approach will open new avenues towards in‐cell EPR.
Reactivity of Bridged Pentelidene Complexes with Isonitriles: A New Way to Pentel‐Containing Heterocycles
Authors: Seidl Michael , Schiffer Michael , Bodensteiner Michael , Timoshkin Alexey Y. , Scheer Manfred
Published: August 2013

The reaction of [Cp*E{W(CO)5}2] (E=P (1 a), As (1 b); Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl) with isonitriles RNC (R=tBu, cyclohexyl (Cy), nBu) depends on the steric demand of the substituent at the isonitrile as well as on the stoichiometry of the starting materials. With tBuNC only the Lewis acid/base adducts [Cp*E{W(CO)5}2(CNtBu)] (E=P (2 a), As (2 b)) are formed. The use of Cy and n‐butylisonitrile leads first to the formation of the Lewis acid/base adduct, but only at low temperatures. At ambient temperatures, a rearrangement occurs and bicyclo[3.2.0]heptane derivatives of the type [{C(Me)C(CH2)C(Me)C(Me)C(Me)}C(NR)‐ E{W(CO)5}2] (E=P, As; R=Cy, nBu) (3 a‐Cy, 3 b‐Cy, 3 a‐nBu and 3 b‐nBu) are obtained. The use of a further equivalent of isonitrile results in products revealing two new structural motifs, the four‐membered ring derivatives [C(Cp*)N(R)C(NR)E{W(CO)5}2] (4: E=P, As; R=Cy, nBu) and the bicyclic complexes [[{C(Me)C‐ (CH2)C(Me)C(Me)C(Me)}C(NR)2‐ E{W(CO)5}2] (5: E=As; R=Cy). The reaction pathway depends on the substituent at the isonitrile. By treatment of 1 a with two equivalents of CyNC only a 2H‐1,3‐azaphosphet complex 4 a‐Cy (E=P; R=Cy) is formed. Treatment of 1 b with two equivalents of CyNC exclusively leads to the complex 5 b‐Cy (E=As; R=Cy). Treatment of 1 a with two equivalents of nBuNC results in a mixture of complexes, the 2H‐1,3‐azaphosphet 4 a‐nBu (E=P; R=nBu) and the bicyclic complex 5 a‐nBu (E=P; R=nBu). For the arsenidene complex 1 b a mixture of the 2H‐1,3‐azarsete complex 4 b‐nBu (E=As; R=nBu) and the bicyclic complex 5 b‐nBu (E=P, As; R=Cy, nBu) is obtained. Complex 4 b‐nBu is the first example of a 2H‐1,3‐azarsete complex. All products have been characterized by using mass spectrometry, NMR spectroscopy, and X‐ray diffraction analysis.
Individuelle Förderung im Chemieunterricht – Der Förderkreis am Beispiel der Unterrichtseinheit „Laborführerschein“
Authors: Raguse Karola , Weber‐Peukert Gisela , Woldt Patrick , Lotz Alexander
Published: August 2013

Ziel des Beitrags ist es, Lehrerinnen und Lehrer mit einer praxistauglichen Unterrichtskonzeption vertraut zu machen, die individuelles Lernen ermöglicht und die damit verbundene Förderung von Schülerinnen und Schülern und deren Entwicklung zum selbstständigen Lerner in den Mittelpunkt stellt. Am Beispiel „Laborführerschein“ wird ein in sich konsistentes und praxistaugliches Förderkonzept vorgestellt. Über die grafische Darstellung des Förderkreismodells werden die verschiedenen Strukturelemente eines kompetenzorientierten Unterrichtsarrangements und deren Verzahnung untereinander veranschaulicht. Das mehrfach erprobte Unterrichtsarrangement ist Output orientiert und greift für Planung, Durchführung und Reflexion konsequent die Voraussetzungen der Lernenden auf. Die wiederholt diagnostizierten Lernstände fließen wiederkehrend in den Unterrichtsprozess ein und bestimmen den individuellen Lernprozess. Eine besondere Akzentuierung erfährt dabei der reflektierte Umgang mit dem Selbstkonzept der Lernenden, der Schülerinnen und Schülern helfen soll, zunehmend Verantwortung für den eigenen Lernprozess zu übernehmen.
A 2‐stage ovarian cancer screening strategy using the Risk of Ovarian Cancer Algorithm (ROCA) identifies early‐stage incident cancers and demonstrates high positive predictive value
Authors: Lu Karen H. , Skates Steven , Hernandez Mary A. , Bedi Deepak , Bevers Therese , Leeds Leroy , Moore Richard , Granai Cornelius , Harris Steven , Newland William , Adeyinka Olasunkanmi , Geffen Jeremy , Deavers Michael T. , Sun Charlotte C. , Horick Nora , Fritsche Herbert , Bast Robert C.
Published: August 2013

BACKGROUND

A 2‐stage ovarian cancer screening strategy was evaluated that incorporates change of carbohydrate antigen 125 (CA125) levels over time and age to estimate risk of ovarian cancer. Women with high‐risk scores were referred for transvaginal ultrasound (TVS).

METHODS

A single‐arm, prospective study of postmenopausal women was conducted. Participants underwent an annual CA125 blood test. Based on the Risk of Ovarian Cancer Algorithm (ROCA) result, women were triaged to next annual CA125 test (low risk), repeat CA125 test in 3 months (intermediate risk), or TVS and referral to a gynecologic oncologist (high risk).

RESULTS

A total of 4051 women participated over 11 years. The average annual rate of referral to a CA125 test in 3 months was 5.8%, and the average annual referral rate to TVS and review by a gynecologic oncologist was 0.9%. Ten women underwent surgery on the basis of TVS, with 4 invasive ovarian cancers (1 with stage IA disease, 2 with stage IC disease, and 1 with stage IIB disease), 2 ovarian tumors of low malignant potential (both stage IA), 1 endometrial cancer (stage I), and 3 benign ovarian tumors, providing a positive predictive value of 40% (95% confidence interval = 12.2%, 73.8%) for detecting invasive ovarian cancer. The specificity was 99.9% (95% confidence interval = 99.7%, 100%). All 4 women with invasive ovarian cancer were enrolled in the study for at least 3 years with low‐risk annual CA125 test values prior to rising CA125 levels.

CONCLUSIONS

ROCA followed by TVS demonstrated excellent specificity and positive predictive value in a population of US women at average risk for ovarian cancer. Cancer 2013;119:3454–3461.. © 2013 American Cancer Society.
Gain of 1q is associated with inferior event‐free and overall survival in patients with favorable histology Wilms tumor: A report from the Children's Oncology Group
Authors: Gratias Eric J. , Jennings Lawrence J. , Anderson James R. , Dome Jeffrey S. , Grundy Paul , Perlman Elizabeth J.
Published: August 2013

BACKGROUND

Wilms tumor is the most common childhood renal tumor. Although the majority of patients with favorable histology Wilms tumor (FHWT) have good outcomes, some patients still experience disease recurrence and death from disease. The goal of the current study was to determine whether tumor‐specific chromosome 1q gain is associated with event‐free survival (EFS) and overall survival (OS) in patients with FHWT.

METHODS

Unilateral FHWT samples were obtained from patients enrolled on National Wilms Tumor Study‐4 and Pediatric Oncology Group Wilms Biology Study (POG 9046). 1q gain, 1p loss, and 16q loss were determined using multiplex ligation‐dependent probe amplification.

RESULTS

The 8‐year EFS rate was 87% (95% confidence interval [95% CI], 82%‐91%) for the entire cohort of 212 patients. Tumors from 58 of 212 patients (27%) displayed 1q gain. A strong relationship between 1q gain and 1p/16q loss was observed. The 8‐year EFS rate was 76% (95% CI, 63%‐85%) for patients with 1q gain and 93% (95% CI, 87%‐96%) for those lacking 1q gain (P = .0024). The 8‐year OS rate was 89% (95% CI, 78%‐95%) for those with 1q gain and 98% (95% CI, 94%‐99%) for those lacking 1q gain (P = .0075). Gain of 1q was not found to correlate with disease stage (P = .16). After stratification for stage of disease, 1q gain was associated with a significantly increased risk of disease recurrence (risk ratio estimate: 2.72;P = .0089).

CONCLUSIONS

Gain of 1q may provide a valuable prognostic marker with which to stratify therapy for patients with FHWT. A confirmatory study is necessary before this biomarker is incorporated into the risk stratification schema of future therapeutic studies. Cancer 2013;119:3887–3894. © 2013 American Cancer Society.
Mammographic screening interval in relation to tumor characteristics and false‐positive risk by race/ethnicity and age
Authors: O'Meara Ellen S. , Zhu Weiwei , Hubbard Rebecca A. , Braithwaite Dejana , Kerlikowske Karla , Dittus Kim L. , Geller Berta , Wernli Karen J. , Miglioretti Diana L.
Published: August 2013

BACKGROUND

Biennial screening mammography retains most of the benefits of annual breast cancer screening with reduced harms. Whether screening guidelines based on race/ethnicity and age would be more effective than age‐based guidelines is unknown.

METHODS

Mammography data from the Breast Cancer Surveillance Consortium were linked to pathology and tumor databases. The authors identified women aged 40 to 74 years who underwent annual, biennial, or triennial screening mammography between 1994 and 2008. Logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (95% CI) of adverse tumor characteristics among 14,396 incident breast cancer cases and 10‐year cumulative risks of false‐positive recall and biopsy recommendation among 1,276,312 noncases.

RESULTS

No increased risk of adverse tumor characteristics associated with biennial versus annual screening were noted in white women, black women, Hispanic women aged 40 to 49 years, or Asian women aged 50 to 74 years. Hispanic women aged 50 to 74 years who screened biennially versus annually were found to have an increased risk of late‐stage disease (OR, 1.6; 95% CI, 1.0‐2.5) and large tumors (OR, 1.6; 95% CI, 1.1‐2.4). Asian women aged 40 to 49 years who underwent biennial screening had an elevated risk of positive lymph nodes (OR, 3.1; 95% CI, 1.3‐7.1). No elevated risks were associated with triennial versus biennial screening. Cumulative false‐positive risks decreased markedly with a longer screening interval.

CONCLUSIONS

The authors found limited evidence of elevated risks of adverse tumor characteristics with biennial versus annual screening, whereas cumulative false‐positive risks were lower. However, elevated risks of late‐stage disease in Hispanic women and lymph node‐positive disease in younger Asian women who screened less often than annually warrant consideration and replication. Cancer 2013;119:3959–3967. © 2013 American Cancer Society.
To preserve or not to preserve
Authors: Mersereau Jennifer E. , Goodman Linnea R. , Deal Allison M. , Gorman Jessica R. , Whitcomb Brian W. , Su H. Irene
Published: August 2013

BACKGROUND

The decision to pursue fertility preservation (FP) after a cancer diagnosis is complex. We examined the prevalence of high decisional conflict and specific factors that influence this decision using the Decisional Conflict Scale (DCS).

METHODS

The FIRST project is a web‐based survey of female cancer survivors (ages 18‐44 years) who have undergone gonadotoxic treatment. We evaluated the association between recalled decisional conflict and referral to FP counseling and demographic, socioeconomic, and cancer variables.

RESULTS

Of 208 participants, 115 subjects (55%) had scores consistent with high decisional conflict (DCS score >37.5 of 100), and 43 (21%) were in the moderate range (25‐37.5). In unadjusted analysis, high decisional conflict was associated with lack of referral to FP consultation, not undergoing FP treatment, concerns regarding FP cost, length of survivorship, lower income, education, partner status, and cancer type. In multivariable analysis, significantly higher prevalence of high decisional conflict was observed in participants who were not referred for FP consultation (prevalence ratio [PR], 1.25; 95% confidence interval [CI], 1.06‐1.47), as well as in participants who reported cost of FP services to be prohibitive (PR, 1.16 [95% CI, 1.03‐1.31]). Prevalence of high DCS was lower for women who underwent FP treatment (PR, 0.67 [95% CI, 0.52‐0.86]).

CONCLUSIONS

In this study of female young adult cancer survivors, the majority recalled significant decisional conflict about FP at cancer diagnosis. Increasing access to FP via referral for counseling and cost reduction may decrease decisional conflict about FP for young patients struggling with cancer and fertility decisions. Cancer 2013;119:4044–4050. © 2013 American Cancer Society.
Cancer drug prices and the free‐market forces
Authors: Kantarjian Hagop , Zwelling Leonard
Published: August 2013

The authors discuss why market forces have not been effective in setting cancer drug prices to reasonable levels. Generic cancer drugs are priced too low, which results in drug shortages. Patented cancer drugs are priced too high, which may be harming patients with cancer and the health care system.
The cross‐modal aspect of mouse visual cortex plasticity induced by monocular enucleation is age dependent
Authors: Nys Julie , Aerts Jeroen , Ytebrouck Ellen , Vreysen Samme , Laeremans Annelies , Arckens Lutgarde
Published: August 2013

Monocular enucleation (ME) drastically affects the contralateral visual cortex, where plasticity phenomena drive specific adaptations to compensate for the unilateral loss of vision. In adult mice, complete reactivation of deprived visual cortex involves an early visually driven recovery followed by multimodal plasticity 3 to 7 weeks post ME (Van Brussel et al. [] Cereb. Cortex 21:2133–2146). Here, we specifically investigated the age dependence of the onset and the exact timing of both ME‐induced reactivation processes by comparing cortical activity patterns of mice enucleated at postnatal day (P) 45, 90, or 120. A swifter open‐eye potentiated reactivation characterized the binocular visual cortex of P45 mice. Nevertheless, even after 7 weeks, the reactivation remained incomplete, especially in the monocular cortex medial to V1. In comparison with P45, emergent cross‐modal participation was demonstrated in P90 animals, although robust reactivation similar to enucleated adults (P120) was not achieved yet. Concomitantly, at 7 weeks post ME, somatosensory and auditory cortex shifted from a hypoactive state in P45 to hyperactivity in P120. Thus, we provide evidence for a presensitive period in which gradual recruitment of cross‐modal recovery upon long‐term ME coincides with the transition from adolescence to adulthood in mice. J. Comp. Neurol. 522:950–970, 2014. © 2013 Wiley Periodicals, Inc.
Differential Pharmacokinetics of Ganitumab in Patients With Metastatic Pancreatic Cancer Versus Other Advanced Solid Cancers
Authors: Zhu Min , Gosselin Nathalie H. , Kuchimanchi Mita , Johnson Jessica , McCaffery Ian , Mouksassi Mohamad‐Samer , Loh Elwyn , Lu Jian‐Feng
Published: August 2013

Ganitumab is an investigational, fully human monoclonal antibody antagonist of the insulin‐like growth factor‐1 receptor (IGF1R) that has shown trends towards improved progression‐free survival and overall survival in a phase 2 pancreatic cancer clinical trial. To characterize ganitumab pharmacokinetics (PK) and identify factors affecting PK, ganitumab serum concentration data from three clinical trials were analyzed. The PK of ganitumab as monotherapy and in combination with gemcitabine in patients with pancreatic or non‐pancreatic cancer were assessed with a non‐linear mixed‐effect model. We found that ganitumab exhibited linear and time‐invariant kinetics. A two‐compartment model adequately described data over a dose range of 1–20 mg/kg with good predictive capability. Typical clearance and central volume of distribution values were 1.7‐ and 1.3‐fold higher, respectively, in patients with pancreatic cancer than in patients with other advanced solid cancers, resulting in lower ganitumab exposure. Covariate analysis was used to evaluate effects of cancer type, gemcitabine coadministration, clinical study, demographics, and laboratory values on ganitumab PK. Pancreatic cancer type was the most significant covariate on clearance along with weight, albumin, and serum creatinine. Gemcitabine coadministration did not affect ganitumab clearance. Thus, disease state can significantly affect PK and should be considered when selecting the clinically effective dose.
Pharmacokinetics of a Single 150‐mg Intravenous Infusion of Fosaprepitant: Effects of Concentration and Infusion Time in Healthy Japanese Men
Authors: Azuma Junichi , Fukase Hiroyuki
Published: August 2013

Purpose

Fosaprepitant dimeglumine (Proemend® for Injection; formerly ONO‐7847) is a phosphorylated prodrug that is rapidly converted to aprepitant, an oral selective neurokinin‐1 receptor antagonist approved for the prevention of chemotherapy‐induced nausea and vomiting. This Phase 1 study evaluated the pharmacokinetics, safety, and tolerability of fosaprepitant after a single intravenous dose in healthy Japanese men.

Methods

All fosaprepitant‐ or placebo‐treated subjects were assessed for the occurrence of adverse events.

Results

Ninety subjects were randomized into treatment and placebo groups. The plasma fosaprepitant concentrations generally reached steady state by 15 minutes after the start of infusion. Although the maximum concentration was proportional to the infusion time, no clinically important pharmacokinetic differences were noted in the cohorts examined. Most adverse events observed in this study were associated with infusion site reactions, which tended toward a higher incidence with shorter infusion times. These events were mild in severity.

Conclusions

These findings demonstrate that fosaprepitant at different concentrations and over different infusion times has a pharmacokinetic and safety profile that is comparable to the intravenous dose previously established as efficacious and well tolerated. The dosing flexibility afforded by the single‐dose fosaprepitant formulation should lead to greater convenience for patients and health care providers.
Structure and optical property of BexZn1‐xO nanorod arrays
Authors: Zhang Wenhui , Wu Yanyan , Ji Xu , Xiang Rong , Gui Xuchun , Zhu Yuan , Tang Zikang
Published: August 2013

BexZn1‐xO nanorod arrays with high crystalline quality were fabricated on Si substrate by a simple, low‐cost hydrothermal method. The effect of Be‐corporation on the structure, morphology and optical property of ZnO nanorod arrays was investigated. The diameter of BexZn1‐xO nanorods gradually decreased and the length of them increased with increasing Be concentration. Edge emissions of the BexZn1‐xO nanorods show a obvious blue shift upon the increase of the Be content.
An Efficient Procedure to Identify and Quantify New Molecules for Insulating Gas Mixtures
Authors: Franck C. M. , Dahl D. A. , Rabie M. , Haefliger P. , Koch M.
Published: August 2013

In this contribution, a new procedure to systematically identify and quantify novel molecular gases with low global warming potential for application in high voltage insulation as gas mixtures is presented. The attention is focused on highly efficient procedures to be able to scan a large number of candidate gases. To identify new molecules, we derived an empirical correlation between the electric strength of a gas and certain molecular properties, like polarizability or dipole moment, which can be calculated by means of density functional theory. The swarm parameters of these pre‐selected molecules in mixtures with buffer gases is then quantified, using a newly set‐up Pulsed Townsend experiment. The setup operates with a high degree of automation to enable systematic evaluation of gas mixtures not to miss possible synergistic effects. Key element of this PT setup is a new photocathode that works with a high quantum efficiency and long lifetime even when exposed to reactive species during the measurements. Moreover, for an automated operation it is important to know precisely in which range the experiment can be operated, i.e. for example to know up to which electron density space charge effects can be neglected. Finally, the measured swarm parameters need to be translated into breakdown voltage strengths of different electrode arrangements and different applied voltage wave shapes. For this, a model of the the streamer to leader transition in SF6 will be applied to other strong electronegative gases in future studies to test if the model is universally valid. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)