bluuebunny/crossref_metadata_2025 huggingface dataset:
Stage-Level and Individual-Level distinction in morphological variation
Authors: Rivas Javier , Brown Esther L.
Published: January 2013

This work examines the role of the stage-level (SL)/individual-level (IL) distinction applied to nouns in a case of morphosyntactic regularization in Spanish: variable reanalysis of the NP argument as subject in the presentational haber construction (había/habían perros). We conduct variationist, quantitative analyses on all instances of existential haber with a plural NP in corpora of spoken Puerto Rican Spanish (>500,000 words) to determine the linguistic factor groups that promote reanalysis and, hence, pluralized forms. Results of variable rule analyses reveal that the SL-IL distinction constrains the regularization. IL predicates significantly favor haber regularization (e.g., habían muchas personas de las Antillas ‘there were a lot of people from the Antillas’) whereas SL predicates significantly disfavor pluralized forms (este año hubo menos tiros que en años pasados ‘this year there were fewer shots fired than previous years’). These results are interpreted from within a usage-based framework in which the status of the noun introduced in the [haber + NP] construction, as either a likely or unlikely subject for haber, influences the analogical leveling. IL predicates are more prototypical nouns than SL predicates because the former are temporally persistent. IL predicates promote nouns’ candidacy as subjects over direct objects because prototypical subjects present two temporally-persistent characteristics: independence existence and referentiality. As a result, IL predicates increase the likelihood of reanalyzing the direct object as subject, thus triggering agreement of the verbal form with plural NPs. SL predicates, on the other hand, because they display low temporal stability, inhibit regularization.
Temporal constraints in the use of demonstratives in Iberian Spanish
Authors: Zulaica Hernández Iker
Published: January 2013

Natural linguistic data show that a close relationship exists among demonstratives and time in Spanish. Such connection appears to be of a pragmatic nature whereby linguistic expressions that encode or denote time license the use of demonstratives under certain conditions.The aforementioned connection time-demonstration occurs when speakers employ demonstratives to refer to objects within the textual world (i.e. discourse referents). In this paper I explore the temporal constraints that impose restrictions in the use of demonstratives in Spanish and argue in favor of characterizing the relationship time-demonstration as a discourse deixis phenomenon in close connection with time deixis. The co-referential link that gets established between the distal demonstrative and the temporal expression is formalized and a presuppositional characterization provided for the three demonstratives in their discourse-deictic use.
Política y políticas para la TDT en Argentina y Chile: ¿ruptura del statu quo?
Authors:   Universidad Nacional de Quilmes (Argentina), RODRÍGUEZ MIRANDA CARLA
Published: January 2013

El artículo analiza la construcción de la arquitectura política y económica de la televisión digital terrestre en Argentina y Chile a partir de dos categorías de análisis: el rol del Estado y el paralelismo político. El estudio indaga sobre las dinámicas políticas que se establecen en el proceso de elaboración de las políticas de comunicación, en particular se focaliza en el papel de las televisoras del tercer sector que reclaman una licencia para transmitir en condición legal. A partir de una estrategia descriptiva y exploratoria basada en el método comparativo, se concluye que en ambos países emerge un sistema de televisión digital anclado en el mismo patrón de poder relacional entre medios y política, lo cual no posibilita quebrar el statu quo
La televisión conectada: ventajas e inconvenientes del estándar HbbTV
Authors:   Universitat Abat Oliba CEU (España), FONDEVILA GASCÓN JOAN FRANCESC
Published: January 2013

El fenómeno de asimilación e interacción entre televisión e Internet está creciendo de forma significativa en los últimos años. Eso se está traduciendo en un impulso en la penetración de la televisión conectada e híbrida, hasta el punto de la irrupción en escena el estándar HbbTV (Hybrid Broadcast and Broadband TV). En este artículo analizamos las claves de este estándar y realizamos un estudio cuantitativo sobre sus implicaciones en la audiencia, en términos de calidad de contenidos, sinergias Internet-televisión-redes sociales, inclusión de publicidad interactiva y otros parámetros del nuevo escenario.
Periodista multimedia interactivo: eje de los grupos de comunicación españoles
Authors:   Universidad Complutense de Madrid (España), RICO MARTA
Published: January 2013

Este texto muestra cómo la integración de las redacciones tradicionales ha revolucionado la gestión de personal en los grupos de comunicación al surgir una nueva figura profesional, el periodista multimedia interactivo, que se ha convertido en pieza clave de los departamentos de recursos humanos. Se han redefinido los puestos de trabajo, se han determinado los perfiles necesarios, se ha modificado la selección de personal y la formación, y se han establecido nuevas formas contractuales. Todo ello porque las redacciones multimedia precisan de un periodista multiplataforma, multifuncional, interactivo y con una preparación específica para desarrollar una labor muy concreta. Esto, unido a una reducción de costos, ha promovido nuevas relaciones entre los profesionales y su empresa o grupo de comunicación. Por tanto, para tal fin, en este estudio se han analizado textos y se han empleado la observación y el método Delphi
Gastric Neuroendocrine Tumors in Our Institutions According to the WHO 2010 Classification
Authors: Endo Shunji , Dousei Tsutomu , Yoshikawa Yukinobu , Hatanaka Nobutaka , Taniyama Kiyomi , Yamauchi Amane , Kamiike Wataru , Nishijima Junichi
Published: January 2013

In 2010, World Health Organization classified gastric neuroendocrine tumor (NET) as follows: NET grade (G) 1, NET G2, neuroendocrine carcinoma (NEC). We reviewed 22 gastric NETs that were encountered in our institutions. Nine, 6, and 4 were NET G1, G2, and NEC, respectively. We also encountered 3 NET G3. NET G1 was treated with observation in 2 patients, endoscopic mucosal resection (EMR) in 3, and gastrectomy in 4 patients. No recurrence was experienced during a median of 53 months of follow-up. All NET G2 was treated with gastrectomy. No patient experienced recurrence during a median of 25 months of follow-up. NET G3 was treated with gastrectomy. One patient died of liver metastasis 52 months after gastrectomy. For NEC, gastrectomy was performed in 3 cases and no patients died of tumor-related death. We conclude that the prognoses of NET G1 and G2 were good. We also experienced long-term survivors of NEC. An accumulation of more patients is needed for further investigation.
Adenocarcinoma Arising From Heterotopic Pancreas in the Duodenum
Authors: Kinoshita Hiroyuki , Yamaguchi Shunsuke , Shimizu Atsushi , Sakata Yoshifumi , Arii Kazuo , Mori Kazunari , Nasu Tetsushi
Published: January 2013

We present a rare case of adenocarcinoma arising from a heterotopic pancreas in the duodenum, and review the associated literature. A 62-year-old woman was admitted to our hospital, complaining of vomiting and epigastralgia. Imaging studies revealed advanced gastric cancer with a gastric outlet obstruction. Whipple's operation and resection of the regional lymph node were performed because of a direct invasion to the pancreas. Histopathologic examination of the resected specimen demonstrated the malignant transformation of a hetrotopic pancreas in the duodenum. At the 12-month follow-up, there was no recurrence of symptoms. The prognosis of adenocarcinoma arising from a heterotopic pancreas is not known. Further accumulation of cases and investigation of this entity are necessary.
A Practical Procedure for Reduction of Primary, Secondary and Tertiary Amides to Amines
Authors: Reeves Jonathan T. , Tan Zhulin , Marsini Maurice A. , Han Zhengxu S. , Xu Yibo , Reeves Diana C. , Lee Heewon , Lu Bruce Z. , Senanayake Chris H.
Published: January 2013

A mild and general procedure for reduction of primary, secondary, and tertiary amides using catalytic triruthenium dodecacarbonyl and 1,1,3,3‐tetramethyldisiloxane as reductant is described. The reaction is tolerant of numerous functional groups, and the amine products can often be isolated by direct crystallization as hydrochloride salts. The catalyst and silane are commercially available, air stable, and inexpensive, making the procedure accessible for both laboratory and large‐scale applications.
Continuum model validation of gas jet plume injection into a gas–solid bubbling fluidized bed
Authors: Rangarajan Deepak , Curtis Jennifer S. , Benyahia Sofiane , Mychkovsky Alexander G.
Published: January 2013

A continuum gas–solid model that includes descriptions for solid frictional stress and a turbulent gas phase is evaluated against published experimental measurements of mean and fluctuating velocity inside the jet plume region of a bubbling fluidized bed with a high‐speed vertical jet injection. The main uncertainties in closure relations necessary in the continuum model are first identified and then determined using available experimental data. The overall model shows good agreement with both the gas and particle experimental velocity profiles. The trends in the centerline mean and fluctuating velocity with change in the fluidized state of the emulsion are also captured favorably. Main deviations between the model and experiment are noted and possible reasons for the mismatch are discussed. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3247–3264, 2013
Small Targeted Cytotoxics: Current State and Promises from DNA‐Encoded Chemical Libraries
Authors: Krall Nikolaus , Scheuermann Jörg , Neri Dario
Published: January 2013

The targeted delivery of potent cytotoxic agents has emerged as a promising strategy for the treatment of cancer and other serious conditions. Traditionally, antibodies against markers of disease have been used as drug‐delivery vehicles. More recently, lower molecular weight ligands have been proposed for the generation of a novel class of targeted cytotoxics with improved properties. Advances in this field crucially rely on efficient methods for the identification and optimization of organic molecules capable of high‐affinity binding and selective recognition of target proteins. The advent of DNA‐encoded chemical libraries allows the construction and screening of compound collections of unprecedented size. In this Review, we survey developments in the field of small ligand‐based targeted cytotoxics and show how innovative library technologies will help develop the drugs of the future.
Flame‐retardant and morphological analysis of nitrogen heterocycle‐modified poly(vinyl alcohol) and their application for adsorption of heavy metal ions
Authors: Karpagam S. , Guhanathan S.
Published: January 2013

The functional modification of poly (vinyl alcohol) (PVA) was conducted through phosphorus containing nitrogen heterocycles. This has been believed to have extensive thermal stability and heavy metal ion adsorption in the area of polymers. The heterocyclic modified polymers were characterized by Infra red (FTIR), Nuclear magnetic resonance spectroscopy, and elemental analysis. Thermogravimetric analysis studies displayed that phosphorus‐containing five membered and fused heterocyclic based PVA were less thermally stable than six membered compounds. Differential scanning calorimetric studies reported that the glass transition and melting point temperature of the heterocyclic modified PVA was higher than the pure PVA. X‐ray diffraction studies were done to analyze the structure of the modified polymer. Atomic force microscopy surface scans showed that the modified polymeric surface was found to have rough in micrometer scale. Modified PVA showed improved thermal stability, flame retardance, organosolubility, and surface roughness. The adsorption capacities of the modified PVA were determined for several heavy metal ions with the variation of pH. The adsorption capacity was found as 289 mg Pd2+/g of imidazole modified PVA and exhibited higher than other modified PVA. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Micellization behavior of ionic liquid surfactants with two hydrophobic tail chains in aqueous solution
Authors: Ding Wei , Liu Kang , Liu Xiaojun , Luan Huoxin , Lv Chongfu , Yu Tao , Qu Guangmiao
Published: January 2013

The drop volume method was used to determine the surface tensions of two series of polymerizable ionic liquid surfactants, namely, 1‐acryloyloxypropyl‐3‐alkylimidazolium chloride [APCnim][Cl] (n = 8, 10, 12) containing two hydrophobic tail chains and 1‐propionyloxypropyl‐3‐alkylimidazolium chloride [PPCnim][Cl] (n = 8, 10, 12), which showed similar structures with [APCnim][Cl] (n = 8, 10, 12) at 25°C. The surface properties of the surfactants were also compared. Furthermore, the thermodynamic behavior of [PPCnim][Cl] (n = 10, 12, 14) micellization in aqueous solution and the enthalpy–entropy compensation phenomenon were studied. The two kinds of surfactants had high surface activity. Double bonds had almost no effect on the surface properties of [APCnim][Cl]. The micellization of [PPCnim][Cl] in aqueous solution was spontaneous and entropy‐driven. For the surfactant with specific structure, micellization ability initially increased and then decreased with temperature increase. The entropic contribution to Gibbs free energy change tended to decrease, whereas the enthalpic contribution increased. In addition, the enthalpy–entropy compensation phenomenon occurred during the micellization process. For all [PPCnim][Cl], the compensation temperature was (314 ± 1) K, which remained unaffected by the surfactant molecular structure. However, when the hydrophobic carbon chain length increased, both micelle formation ability and stability increased. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synergistic effect of organo‐montmorillonite on intumescent flame retardant ethylene‐octene copolymer
Authors: Guo Jianbing , He Min , Li Qingfeng , Yu Jie , Qin Shuhao
Published: January 2013

Nanocomposite of thermoplastic elastomer ethylene‐octene copolymer/maleated ethylene‐octene (POE/POE‐g‐MAH) with organo‐montmorillonite (OMMT, 11 wt %) as masterbatch have been obtained by melt blending and it has been characterized by transmission electron microscopy (TEM). Flame retardant POE/POE‐g‐MAH/OMMT/ammonium polyphosphate‐pentaerythritol (APP‐PER) (an intumescent flame retardant with 75 wt % ammonium polyphosphate and 25 wt % pentaerythritol) composites were prepared by using melting processing to study their structures, flame‐retardancy, thermal, and mechanical properties. TEM showed exfoliated structures throughout POE/POE‐g‐MAH/OMMT masterbatch and POE/POE‐g‐MAH/OMMT/APP‐PER nanocomposites. Synergistic effect was observed between OMMT and APP‐PER resulting in significant improvements on thermal stability, flame‐retardancy and mechanical properties in the POE/POE‐g‐MAH/OMMT/APP‐PER nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Layer‐by‐layer assembly of poly(allylamine hydrochloride)/polyurethane and its loading and release behavior for methylene orange
Authors: Jian Wenjiao , Xu Shimei , Wang Jide , Feng Shun
Published: January 2013

Here, layer‐by‐layer technique was used for sequential adsorption of oppositely charged polymer poly(allylamine hydrochloride) (PAH) and polyurethane (PU) through electrostatic interaction. 10 and 10.5 bilayer films were prepared separately, methylene orange (MO) was used as a model drug to evaluate the potential ability of this multilayer film used in drug delivery system. Experimental results showed the ability of loading and release of MO from the film was significantly influenced by pH and salt concentration, the loading rate of MO was faster and larger with increasing salt concentration or decreasing pH of MO solution, the release rate of MO was faster at higher salt concentration or in alkali solution. The result also indicated that the film had a good reversibility of loading and release. PAH/PU film could be a promising drug delivery system because of its biocompatibility, biodegradation and above properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis of functional poly(styrene)‐block‐(methyl methacrylate/methacrylic acid) by homogeneous reverse atom transfer radical polymerization: Spherical nanoparticles, thermal behavior, self‐aggregation, and morphological properties
Authors: Pizarro Guadalupe del C. , Jeria‐Orell Manuel , Marambio Oscar G. , Olea Andrés F. , Valdés Daniela T. , Geckeler Kurt E.
Published: January 2013

This study investigates the use of homogeneous reverse atom transfer radical polymerization for the synthesis of polystyrene (PS) initiated by conventional radical peroxide with copper bromide in the lower oxidation state and a 2,2′‐bypyridine complex as the catalyst. In a second stage, an amphiphilic block copolymer containing methyl methacrylate (MMA) was synthesized via normal atom transfer radical polymerization in two steps, followed by partial hydrolysis of the methyl ester linkage of the MMA block under acidic conditions. The block copolymer PS699‐b‐P(MMA232/MAA58) obtained had a narrow molecular weight dispersity (Ð < 1.3). The structure of the precursor, PS‐b‐PMMA, and resultant polymer, was characterized and verified by FTIR and 1H‐NMR spectroscopy as well as size exclusion chromatography. The self‐aggregation of PS699‐b‐P(MMA232/MAA58) in organic solvents was monitored by UV spectroscopy, whereas the morphology and size of the formed microaggregates were investigated by transmission electron microscopy and dynamic light scattering. The results indicate that this copolymer formed regular spherical reverse micelles with a core–shell structure. The atomic force micrographs of PS699‐b‐P(MMA232/MAA58) showed a rough surface morphology owing to microphase separation of the block copolymer. In addition, thermal characterization was performed by differential scanning calorimetry and thermogravimetric analysis. The glass transition temperature of PS699‐b‐P(MMA232/MAA58) decreased significantly (65°C), when compared to PS and PMMA, suggesting that an enhanced movement of the polymer chains resulted by the segregation of the hydrolyzed P(MMA232/MAA58) block. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Tuning Catalysts to Tune the Products: Phosphine‐Catalyzed Aza‐Michael Addition Reaction of Hydrazones with Allenoates
Authors: Li Erqing , Xie Peizhong , Yang Lihua , Liang Ling , Huang You
Published: January 2013

A new tunable phosphine‐catalyzed aza‐Michael β‐addition reaction between allenoates and various hydrazones has been developed. These reactions are most‐efficiently promoted by a catalytic amount of phosphine catalysts. These atom‐economical reactions are operationally simple and their corresponding adducts can been achieved in high yields and high selectivity under mild reaction conditions. Further studies revealed that different phosphine catalyst can produce different adducts from the same starting materials.
Efficient Oxidative Degradation of Azo Dyes by a Water‐Soluble Manganese Porphyrin Catalyst
Authors: Saha Tapan Kumar , Frauendorf Holm , John Michael , Dechert Sebastian , Meyer Franc
Published: January 2013

Dyes in wastewater severely affect the nature and quality of water by inhibiting the sunlight penetration into the stream, which thereby reduces the photosynthesis reaction. This poses a serious environmental threat in many developing countries. Recently, new methods for the treatment of colored dye effluent streams have attracted much attention. The [MnIII(tmpyp)]/H2O2 system (tmpyp=meso‐tetrakis(1‐methylpyridinium‐4‐yl)porphyrinato) was now found to degrade various azo dyes with remarkably high efficiency under ambient conditions in aqueous solution at certain pH values. Main products of the catalytic degradation of the dye amaranth by [MnIII(tmpyp)]/H2O2 were analyzed. The reaction mechanism was studied in more detail by using rapid‐scan stopped‐flow spectrophotometry as a function of pH, [catalyst], [H2O2], [dye], and [surfactants]. Spectral analyses and kinetic data suggested rapid formation of an intermediate [MnIII(tmpyp)(OOH)] (a compound 0‐type intermediate), followed by the formation of a relatively stable trans‐dioxomanganese(V) porphyrin complex, [MnV(O)2(tmpyp)] (a compound I analog). The one‐electron reduction of [MnV(O)2(tmpyp)] to [MnIV(O)(tmpyp)] (a compound II analog) was accelerated greatly by amaranth. On the basis of the kinetic and spectroscopic data, a reaction mechanism of the formation of reactive intermediates [MnIII(tmpyp)(OOH)], [MnV(O)2(tmpyp)], and [MnIV(O)(tmpyp)] was proposed.
Structure and Dynamics of Molecular Rods in Membranes: Application of a Spin‐Labeled Rod
Authors: Grimm Christiane , Meyer Thomas , Czapla Sylvia , Nikolaus Jörg , Scheidt Holger A. , Vogel Alexander , Herrmann Andreas , Wessig Pablo , Huster Daniel , Müller Peter
Published: January 2013

Molecular rods consisting of a hydrophobic backbone and terminally varying functional groups have been synthesized for applications for the functionalization of membranes. In the present study, we employ a spin‐labeled analogue of a recently described new class of molecular rods to characterize their dynamic interactions with membranes. By using the different approaches of ESR and NMR spectroscopy, we show that the spin moiety of the membrane‐embedded spin‐labeled rod is localized in the upper chain/glycerol region of membranes of different compositions. The rod is embedded within the membrane in a tilted orientation to adjust for the varying hydrophobic thicknesses of these bilayers. This orientation does not perturb the membrane structure. The water solubility of the rod is increased significantly in the presence of certain cyclodextrins. These cyclodextrins also allow the rods to be extracted from the membrane and incorporated into preformed membranes. The latter will improve the future applications of these rods in cellular systems as stable membrane‐associated anchors for the functionalization of membrane surfaces.
Ionic‐Liquid‐Assisted Synthesis of Uniform Fluorinated B/C‐Codoped TiO2 Nanocrystals and Their Enhanced Visible‐Light Photocatalytic Activity
Authors: Yu Jiaguo , Li Qin , Liu Shengwei , Jaroniec Mietek
Published: January 2013

Exploiting advanced photocatalysts under visible light is of primary significance for the development of environmentally relevant photocatalytic decontamination processes. In this study, the ionic liquid (IL), 1‐butyl‐3‐methylimidazolium tetrafluoroborate, was employed for the first time as both a structure‐directing agent and a dopant for the synthesis of novel fluorinated B/C‐codoped anatase TiO2 nanocrystals (TIL) through hydrothermal hydrolysis of tetrabutyl titanate. These TIL nanocrystals feature uniform crystallite and pore sizes and are stable with respect to phase transitions, crystal ripening, and pore collapse upon calcination treatment. More significantly, these nanocrystals possess abundant localized states and strong visible‐light absorption in a wide range of wavelengths. Because of synergic interactions between titania and codopants, the calcined TIL samples exhibited high visible‐light photocatalytic activity in the presence of oxidizing Rhodamine B (RhB). In particular, 300 °C‐calcined TIL was most photocatalytically active; its activity was much higher than that of TiO1.98N0.02 and reference samples (TW) obtained under identical conditions in the absence of ionic liquid. Furthermore, the possible photocatalytic oxidation mechanism and the active species involved in the RhB degradation photocatalyzed by the TIL samples were primarily investigated experimentally by using different scavengers. It was found that both holes and electrons, as well as their derived active species, such as .OH, contributed to the RhB degradation occurring on the fluorinated B/C‐codoped TiO2 photocatalyst, in terms of both the photocatalytic reaction dynamics and the reaction pathway. The synthesis of the aforementioned novel photocatalyst and the identification of specific active species involved in the photodegradation of dyes could shed new light on the design and synthesis of semiconductor materials with enhanced photocatalytic activity towards organic pollutants.
Periodic Behavior of Lanthanide Coordination within Reverse Micelles
Authors: Ellis Ross J. , Meridiano Yannick , Chiarizia Renato , Berthon Laurence , Muller Julie , Couston Laurent , Antonio Mark R.
Published: January 2013

Trends in lanthanide(III) (LnIII) coordination were investigated within nanoconfined solvation environments. LnIII ions were incorporated into the cores of reverse micelles (RMs) formed with malonamide amphiphiles in n‐heptane by contact with aqueous phases containing nitrate and LnIII; both insert into pre‐organized RM units built up of DMDOHEMA (N,N′‐dimethyl‐N,N′‐dioctylhexylethoxymalonamide) that are either relatively large and hydrated or small and dry, depending on whether the organic phase is acidic or neutral, respectively. Structural aspects of the LnIII complex formation and the RM morphology were obtained by use of XAS (X‐ray absorption spectroscopy) and SAXS (small‐angle X‐ray scattering). The LnIII coordination environments were determined through use of L3‐edge XANES (X‐ray absorption near edge structure) and EXAFS (extended X‐ray absorption fine structure), which provide metrical insights into the chemistry across the period. Hydration numbers for the Eu species were measured using TRLIFS (time‐resolved laser‐induced fluorescence spectroscopy). The picture that emerges from a system‐wide perspective of the LnO interatomic distances and number of coordinating oxygen atoms for the extracted complexes of LnIII in the first half of the series (i.e., Nd, Eu) is that they are different from those in the second half of the series (i.e., Tb, Yb): the number of coordinating oxygen atoms decrease from 9 O for early lanthanides to 8 O for the late ones—a trend that is consistent with the effect of the lanthanide contraction. The environment within the RM, altered by either the presence or absence of acid, also had a pronounced influence on the nitrate coordination mode; for example, the larger, more hydrated, acidic RM core favors monodentate coordination, whereas the small, dry, neutral core favors bidentate coordination to LnIII. These findings show that the coordination chemistry of lanthanides within nanoconfined environments is neither equivalent to the solid nor bulk solution behaviors. Herein we address atomic‐ and mesoscale phenomena in the under‐explored field of lanthanide coordination and periodic behavior within RMs, providing a consilience of fundamental insights into the chemistry of growing importance in technologies as diverse as nanosynthesis and separations science.
Popcorn‐Shaped Magnetic Core–Plasmonic Shell Multifunctional Nanoparticles for the Targeted Magnetic Separation and Enrichment, Label‐Free SERS Imaging, and Photothermal Destruction of Multidrug‐Resistant Bacteria
Authors: Fan Zhen , Senapati Dulal , Khan Sadia Afrin , Singh Anant Kumar , Hamme Ashton , Yust Brian , Sardar Dhiraj , Ray Paresh Chandra
Published: January 2013

Over the last few years, one of the most important and complex problems facing our society is treating infectious diseases caused by multidrug‐resistant bacteria (MDRB), by using current market‐existing antibiotics. Driven by this need, we report for the first time the development of the multifunctional popcorn‐shaped iron magnetic core–gold plasmonic shell nanotechnology‐driven approach for targeted magnetic separation and enrichment, label‐free surface‐enhanced Raman spectroscopy (SERS) detection, and the selective photothermal destruction of MDR Salmonella DT104. Due to the presence of the “lightning‐rod effect”, the core–shell popcorn‐shaped gold‐nanoparticle tips provided a huge field of SERS enhancement. The experimental data show that the M3038 antibody‐conjugated nanoparticles can be used for targeted separation and SERS imaging of MDR Salmonella DT104. A targeted photothermal‐lysis experiment, by using 670 nm light at 1.5 W cm−2 for 10 min, results in selective and irreparable cellular‐damage to MDR Salmonella. We discuss the possible mechanism and operating principle for the targeted separation, label‐free SERS imaging, and photothermal destruction of MDRB by using the popcorn‐shaped magnetic/plasmonic nanotechnology.
Halogenation of Graphene with Chlorine, Bromine, or Iodine by Exfoliation in a Halogen Atmosphere
Authors: Poh Hwee Ling , Šimek Petr , Sofer Zdeněk , Pumera Martin
Published: January 2013

Nanoarchitectonics on graphene implicates a specific and exact anchoring of molecules or nanoparticles onto the surface of graphene. One such example of an effective anchoring group that is highly reactive is the halogen moiety. Herein we describe a simple and scalable method for the introduction of halogen (chlorine, bromine, and iodine) moieties onto the surface of graphene by thermal exfoliation/reduction of graphite oxide in the corresponding gaseous halogen atmosphere. We characterized the halogenated graphene by using various techniques, including scanning and transmission electron microscopy, Raman spectroscopy, high‐resolution X‐ray photoelectron spectroscopy, and electrochemistry. The halogen atoms that have successfully been attached to the graphene surfaces will serve as basic building blocks for further graphene nanoarchitectonics.
Conformational Analysis of δ‐Lactones by DFT Calculations: The Parent Compound and its Monomethyl and Selected Dimethyl Derivatives
Authors: Weber Fabian , Brückner Reinhard
Published: January 2013

The static and dynamic stereochemistry of unsubstituted δ‐valerolactone, all monomethylated δ‐lactones, and all nongeminally dimethylated δ‐lactones was explored with the B3LYP functional and def2‐TZVPP basis set. A search strategy was employed which allowed the entire conformational space of any (poly‐)substituted δ‐lactone to be scanned. It allowed the lowest threshold conformational interconversion pathways to be mapped. The latter can be visualized in appealingly intuitive yet unprecedented diagrams. They trace the energy versus a circular abscissa which describes the passage of the molecule through one complete conformation interchange. The respective plot is C2‐symmetrical for the parent compound, which is achiral, and C1‐symmetrical for all methylated δ‐lactones, which are chiral.
Phospholipid–Detergent Conjugates as Novel Tools for siRNA Delivery
Authors: Pierrat Philippe , Laverny Gilles , Creusat Gaëlle , Wehrung Patrick , Strub Jean‐Marc , VanDorsselaer Alain , Pons Françoise , Zuber Guy , Lebeau Luc
Published: January 2013

One of the potential benefits of drug delivery systems in medicine is the creation of nanoparticle‐based vectors that deliver a therapeutic cargo in sufficient quantity to a target site to enable a selective effect, width of the therapeutic window depending on the toxicity of the vector and the cargo. In this work, we intended to improve the siRNA delivery efficiency of a new kind of nucleic acid carrier, which is the result of the conjugation of the membrane phospholipid 1,2‐dioleoyl‐sn‐glycero‐3‐phosphocholine (DOPC) to the membrane‐active species Triton X‐100 (TX100). We hypothesized that by improving the biodegradability the cytotoxicity of the conjugate might by reduced, whereas its original transfection potential would be tentatively preserved. DOPC was conjugated to Triton X‐100 through spacers displaying various resistance to chemical hydrolysis and enzyme degradation. The results obtained through in vitro siRNA delivery experiments showed that the initial phosphoester bond can be replaced with a phospho(alkyl)enecarbonate group with no loss in the transfection activity, whereas the associated cytotoxicity was significantly decreased, as assessed by metabolic activity and membrane integrity measurements. The toxicity of the conjugates incorporating a phospho(alkyl)enesuccinnate moiety proved even lower but was clearly balanced with a reduction of the siRNA delivery efficiency. Hydrolytic stability and intracellular degradation of the conjugates were investigated by NMR spectroscopy and mass spectrometry. A general trend was that the more readily degraded conjugates were those with the lower toxicity. Otherwise, the phospho(alkyl)enecarbonate conjugates revealed some hemolytic activity, whereas the parent phosphoester did not. The reason why these conjugates behave differently with respect to hemolysis might be a consequence of unusual fusogenic properties and probably reflects the difference in the stability of the conjugates in the intracellular environment.
Sulfination by Using Pd‐PEPPSI Complexes: Studies into Precatalyst Activation, Cationic and Solvent Effects and the Role of Butoxide Base
Authors: Sayah Mahmoud , Lough Alan J. , Organ Michael G.
Published: January 2013

The activation of PEPPSI precatalysts has been systematically studied in Pd‐catalysed sulfination. Under the reactions conditions of the sulfide and KOtBu in toluene, the first thing that happens is exchange of the two chlorides on the PEPPSI precatalyst with the corresponding sulfides, creating the first resting state; it is via this complex that all Pd enters the catalytic cycle. However, it is also from this same complex that a tri‐Pd complex forms, which is a more persistent resting state. Under standard reaction conditions, this complex is catalytically inactive. However, if additional pyridine or a smaller base (i.e., KOEt) is added, this complex is broken down, presumably initially back to the first resting state and it is again capable of entering the catalytic cycle and completing the sulfination. Of note, once the tri‐Pd complex forms, one equivalent of Pd is lost to the transformation. Related to this, the nature of the cation of the sulfide salt and solvent dielectric is very important to the success of this transformation. That is, the less soluble the salt the better the performance, which can be attributed to lowering sulfide concentration to avoid the movement of the Pd‐NHC complex into the above described off‐cycle sulfinated resting states.
Diastereoselective Access to Polyoxygenated Polycyclic Spirolactones through a Rhodium‐Catalyzed [3+2] Cycloaddition Reaction: Experimental and Theoretical Studies
Authors: Rodier Fabien , Rajzmann Michel , Parrain Jean‐Luc , Chouraqui Gaëlle , Commeiras Laurent
Published: January 2013

The synthetic utility of γ‐alkylidenebutenolides is demonstrated as highly competent dipolarophile partners in both intra‐ and intermolecular rhodium(II)‐catalyzed 1,3‐dipolar cycloaddition reactions. The strength of this approach lies in the formation of spiro[6,4]lactone moieties with the concomitant construction of quaternary spiro stereocenters. Typically, the construction of spirolactones involves an esterification step, which has often been reported as a “biosynthetic pathway”, and often occurs either as or near to the final step of a total synthesis. Furthermore, a convergent and versatile route is reported for the formation of the (5,7) skeleton of molecules that were isolated from the Schisandra genus. Computational studies were performed to provide an overall picture of the mechanism of the intermolecular [3+2] cycloaddition between 2‐diazo‐1,3‐ketoester and protoanemonin and to rationalize the empirical observations. In particular, we have demonstrated for the first time that the rhodium center plays an important role during the cyclization step itself and reacts with the dipolarophile as a complex with the ylide.
One‐Step Synthesis of Small‐Sized and Water‐Soluble NaREF4 Upconversion Nanoparticles for In Vitro Cell Imaging and Drug Delivery
Authors: Yang Dongmei , Dai Yunlu , Ma Pingan , Kang Xiaojiao , Cheng Ziyong , Li Chunxia , Lin Jun
Published: January 2013

Small (2–28 nm) NaREF4 (rare earth (RE)=Nd–Lu, Y) nanoparticles (NPs) were prepared by an oil/water two‐phase approach. Meanwhile, hydrophilic NPs can be obtained through a successful phase‐transition process by introducing the amphiphilic surfactant sodium dodecylsulfate (SDS) into the same reaction system. Hollow‐structured NaREF4 (RE=Y, Yb, Lu) NPs can be fabricated in situ by electron‐beam lithography on solid NPs. The MTT assay indicates that these hydrophilic NPs with hollow structures exhibit good biocompatibility. The as‐prepared hollow‐structured NPs can be used as anti‐cancer drug carriers for drug storage/release investigations. Doxorubicin hydrochloride (DOX) was taken as model drug. The release of DOX from hollow α‐NaLuF4:20 % Yb3+, 2 % Er3+ exhibits a pH‐sensitive release patterns. Confocal microscopy observations indicate that the NPs can be taken up by HeLa cells and show obvious anti‐cancer efficacy. Furthermore, α‐NaLuF4:20 % Yb3+, 2 % Er3+ NPs show bright‐red emission under IR excitation, making both the excitation and emission light fall within the “optical window” of biological tissues. The application of α‐NaLuF4:20 % Yb3+, 2 % Er3+ in the luminescence imaging of cells was also investigated, which shows a bright‐red emission without background noise.
Synthesis and Characterization of Some N‐Aryl‐4‐nitroimidazoles as Potential Insensitive Energy Materials
Authors: Hou Kehui , Liu Zuliang
Published: January 2013

N‐Aryl derivatives of 4‐nitroimidazole have been synthesized under CuI/TBAB catalytic system in excellent yields, using KOH as base in DMF solvent.
A Formal Synthesis of Iridoid 9‐Deoxygelsemide
Authors: Liu Yang , Zhao Gang
Published: January 2013

A formal total synthesis of iridoid 9‐deoxygelsemide has been accomplished. Our approach features the use of (S)‐carvone as starting material, Favorskii rearrangement to construct the functionalized cyclopentane core, Chugeav elimination to introduce the endocyclic double bond, and the ring‐opening reaction of epoxide to build the second five‐membered ring.
Synthesis Study toward Mayamycin
Authors: Wu Kui , Wang Meining , Yao Qizheng , Zhang Ao
Published: January 2013

Natural product mayamycin is the first example in the angucycline class featuring a C‐glycoside linkage at the C5‐position of the benz[a]anthracenone core with remarkable biological activities. We successfully synthesized the two retrosynthetic fragments, but found that the final C‐glycosylation did not occur. Alternatively, an A‐ring saturated aglycon was prepared, but the proposed C‐glycosylation still did not proceed. Finally, a simplified substrate was used and the subsequent C‐glycosylation went through smoothly, giving a two‐ring less analogue of mayamycin.
Synthesis and Cytotoxic Evaluation of Novel Platinum(II) Complexes with C2‐Asymmetric and C2‐Symmetric Chiral Vicinal Diamines
Authors: Zhang Chen , Liu Hongrui , Yang Qing , Chang Jun , Sun Xun
Published: January 2013

A series of new platinum(II) complexes with C2‐asymmetric and C2‐symmetric 1,2‐diamines were designed and synthesized by convenient methods, involving samarium diiodide induced reductive coupling as the key step. The results of cytotoxicity showed that compounds (R,R)‐11a and (S,S)‐11a, two novel platinum(II) complexes with asymmetric 1,2‐diamines, exhibited more potent cytotoxicity than that of oxaliplatin against all leukemia cell lines. Interestingly, (R,R)‐11a and (S,S)‐11a demonstrated less potent activity against three solid cancer cell lines than that of oxaliplatin, which indicated that these two compounds may only selectively inhibit the leukemia cell lines. In contrast, (R,R)‐15a and (S,S)‐15a, two platinum(II) complexes with symmetric 1,2‐diamines, showed similar cytotoxicity to that of oxaliplatin against all leukemia cell lines and more potent activity against solid cancer cell lines. Further flow cytometry data indicated that (R,R)‐11a could obviously arrest leukemia K562 cells in G2/M phases.
Forebrain GABAergic projections to locus coeruleus in mouse
Authors: Dimitrov Eugene L. , Yanagawa Yuchio , Usdin Ted B.
Published: January 2013

The noradrenergic locus coeruleus (LC) regulates arousal, memory, sympathetic nervous system activity, and pain. Forebrain projections to LC have been characterized in rat, cat, and primates, but not systematically in mouse. We surveyed mouse forebrain LC‐projecting neurons by examining retrogradely labeled cells following LC iontophoresis of Fluoro‐Gold and anterograde LC labeling after forebrain injection of biotinylated dextran amine or viral tracer. Similar to other species, the central amygdalar nucleus (CAmy), anterior hypothalamus, paraventricular nucleus, and posterior lateral hypothalamic area (PLH) provide major LC inputs. By using mice expressing green fluorescent protein in γ‐aminobutyric acid (GABA)ergic neurons, we found that more than one‐third of LC‐projecting CAmy and PLH neurons are GABAergic. LC colocalization of biotinylated dextran amine, following CAmy or PLH injection, with either green fluorescent protein or glutamic acid decarboxylase (GAD)65/67 immunoreactivity confirmed these GABAergic projections. CAmy injection of adeno‐associated virus encoding channelrhodopsin‐2‐Venus showed similar fiber labeling and association with GAD65/67‐immunoreactive (ir) and tyrosine hydroxylase (TH)‐ir neurons. CAmy and PLH projections were densest in a pericoerulear zone, but many fibers entered the LC proper. Close apposition between CAmy GABAergic projections and TH‐ir processes suggests that CAmy GABAergic neurons may directly inhibit noradrenergic principal neurons. Direct LC neuron targeting was confirmed by anterograde transneuronal labeling of LC TH‐ir neurons following CAmy or PLH injection of a herpes virus that expresses red fluorescent protein following activation by Cre recombinase in mice that express Cre recombinase in GABAergic neurons. This description of GABAergic projections from the CAmy and PLH to the LC clarifies important forebrain sources of inhibitory control of central nervous system noradrenergic activity. J. Comp. Neurol. 521:2373–2397, 2013. © 2012 Wiley Periodicals, Inc.
Differential dendritic targeting of AMPA receptor subunit mRNAs in adult rat hippocampal principal neurons and interneurons
Authors: Cox David J. , Racca Claudia
Published: January 2013

In hippocampal neurons, AMPA receptors (AMPARs) mediate fast excitatory postsynaptic responses at glutamatergic synapses, and are involved in various forms of synaptic plasticity. Dendritic local protein synthesis of selected AMPAR subunit mRNAs is considered an additional mechanism to independently and rapidly control the strength of individual synapses.

We have used fluorescent in situ hybridization and immunocytochemistry to analyze the localization of AMPAR subunit (GluA1–4) mRNAs and their relationship with the translation machinery in principal cells and interneurons of the adult rat hippocampus. The mRNAs encoding all four AMPAR subunits were detected in the somata and dendrites of CA3 and CA1 pyramidal cells and those of six classes of CA1 γ‐aminobutyric acid (GABA)ergic interneurons. GluA1–4 subunit mRNAs were highly localized to the apical dendrites of pyramidal cells, whereas in interneurons they were present in multiple dendrites. In contrast, in the dentate gyrus, GluA1–4 subunit mRNAs were virtually restricted to the somata and were absent from the dendrites of granule cells. These different regional and cell type‐specific labeling patterns also correlated with the localization of markers for components of the protein synthesis machinery. Our results support the local translation of GluA1–4 mRNAs in dendrites of hippocampal pyramidal cells and CA1 interneurons but not in granule cells of the dentate gyrus. Furthermore, the regional and cell type‐specific differences we observed suggest that each cell type uses distinct ways of regulating the local translation of AMPAR subunits. J. Comp. Neurol. 521:1954–2007, 2013. © 2012 Wiley Periodicals, Inc.
Selective coexpression of synaptic proteins, α‐synuclein, cysteine string protein‐α, synaptophysin, synaptotagmin‐1, and synaptobrevin‐2 in vesicular acetylcholine transporter‐immunoreactive axons in the guinea pig ileum
Authors: Sharrad Dale F. , Gai Wei‐Ping , Brookes Simon J.H.
Published: January 2013

Parkinson's disease is a neurodegenerative disorder characterized by Lewy bodies and neurites composed mainly of the presynaptic protein α‐synuclein. Frequently, Lewy bodies and neurites are identified in the gut of Parkinson's disease patients and may underlie associated gastrointestinal dysfunctions. We recently reported selective expression of α‐synuclein in the axons of cholinergic neurons in the guinea pig and human distal gut; however, it is not clear whether α‐synuclein expression varies along the gut, nor how closely expression is associated with other synaptic proteins. We used multiple‐labeling immunohistochemistry to quantify which neurons in the guinea pig ileum expressed α‐synuclein, cysteine string protein‐α (CSPα), synaptophysin, synaptotagmin‐1, or synaptobrevin‐2 in their axons. Among the 10 neurochemically defined axonal populations, a significantly greater proportion of vesicular acetylcholine transporter‐immunoreactive (VAChT‐IR) varicosities (80% ± 1.7%, n = 4,P< 0.001) contained α‐synuclein immunoreactivity, and a significantly greater proportion of α‐synuclein‐IR axons also contained VAChT immunoreactivity (78% ± 1.3%, n = 4) compared with any of the other nine populations (P< 0.001). Among synaptophysin‐, synaptotagmin‐1‐, synaptobrevin‐2‐, and CSPα‐IR varicosities, 98% ± 0.7%, 96% ± 0.7%, 88% ± 1.6%, and 85% ± 2.9% (n = 4) contained α‐synuclein immunoreactivity, respectively. Among α‐synuclein‐IR varicosities, 96% ± 0.9%, 99% ± 0.6%, 83% ± 1.9%, and 87% ± 2.3% (n = 4) contained synaptophysin‐, synaptotagmin‐1‐, synaptobrevin‐2‐, and CSPα immunoreactivity, respectively. We report a close association between the expression of α‐synuclein and the expression of other synaptic proteins in cholinergic axons in the guinea pig ileum. Selective expression of α‐synuclein may relate to the neurotransmitter system utilized and predispose cholinergic enteric neurons to degeneration in Parkinson's disease. J. Comp. Neurol. 521:2523–2537, 2013. © 2013 Wiley Periodicals, Inc.
Ditopic Arginine‐Aspartate Binders Recognize RGD Loops
Authors: Gersthagen Thomas , Hofmann Johannes , Klärner Frank‐Gerrit , Schmuck Carsten , Schrader Thomas
Published: January 2013

A synthetic strategy was developed for the construction of unsymmetrical arginine tweezers with an additional carboxylate binding site. The ditopic receptor molecules 2 and 3 use two arms to bind arginine–glycine–aspartate (RGD) peptides. However, contrary to expectations from molecular mechanics simulations, the tweezer cavity remains empty, and arginine is bound through a simple guanidinium/phosphate ion‐pair formation. On the other hand, carboxylate recognition by the guanidiniopyrrole moiety operates very efficiently, leading to complexation of ionic amino acids in both linear and cyclic RGD peptides with concentrations in the low micromolar range in a buffered aqueous solution (Kd = 20–30 μM). Truncation of the whole guanidiniopyrrole arm leads to the simple unsymmetrical monophosphate tweezer 1, which lacks the aspartate binder, but restores the arginine inclusion. Tweezer 1 displays a remarkable affinity and selectivity towards cyclic RGD peptides, presumably by a combination of arginine inclusion and additional cooperative hydrogen bonds between its phenolic OH group and the peptide backbone (NMR evidence, Kd = 15–30 μM). Comparison with symmetrical diphosphate tweezers 1a and 2–4 shows that in unsymmetrical tweezers the spacer group must guarantee an open cavity.