bluuebunny/crossref_metadata_2025 huggingface dataset:
Fine‐Tunable Tris(triazolyl)methane Ligands for Copper(I)‐ Catalyzed Azide–Alkyne Cycloaddition Reactions
Authors: Ozkal Erhan , Llanes Patricia , Bravo Fernando , Ferrali Alessandro , Pericàs Miquel A.
Published: March 2014

The preparation of a small library of modular tris(triazolyl)methane ligands for copper‐catalyzed azide–alkyne cycloaddition (CuAAC) reactions is reported. The synthesis of the first generation ligand, tris(1‐benzyl‐1H‐1,2,3‐triazol‐4‐yl)methanol (1a), suitable for work in aqueous systems, is reported at the 50–100 mmol scale through a one‐stage, environmentally benign procedure. One‐stage procedures for the synthesis of tris(aryltriazolyl)methanol structures (1b, phenyl; 1c, para‐trifluoromethylphenyl; 1d, para‐methoxyphenyl) designed for electronic fine‐tuning of catalytic properties, and of 1a‐derived ethers 2c (OBn) and 2d (OMe), designed for CuAAC reactions in organic solvents, are also reported. The complete set of ligands (1a–d, 2c–d) has been tested in the reaction of phenylacetylene with benzyl azide in six different solvents (water, hexane, toluene, dichloromethane, tetrahydrofuran, and acetonitrile), and this has allowed the identification of 1b, 1c and 2c as the ligands depicting the highest tolerance to changes in solvent polarity within the considered family. The comparative performance of ligands 1b–d and 2c in the cycloaddition of a small family of alkynes with benzyl azide in two very different reaction media (1:1 t‐BuOH/H2O and toluene) has been studied as a guide for catalyst selection in specific applications. The applicability of 1c in CuAAC reactions involving functional substrates in toluene has been explored under thermal and microwave‐accelerated (tandem azide formation plus CuAAC reaction) reaction conditions.

magnified image
Asymmetric Synthesis of Substituted Thiolanes through Domino Thia‐Michael–Henry Dynamic Covalent Systemic Resolution using Lipase Catalysis
Authors: Zhang Yan , Vongvilai Pornrapee , Sakulsombat Morakot , Fischer Andreas , Ramström Olof
Published: March 2014

Dynamic systems based on consecutive thia‐Michael and Henry reactions were generated and transformed using lipase‐catalyzed asymmetric transformation. Substituted thiolane structures with three contiguous stereocenters were resolved in the process in high yields and high enantiomeric excesses.

magnified image
Generation of Arylated Quinones by Iron‐Catalyzed Oxidative Arylation of Phenols: Formal Synthesis of Phellodonin, Sarcodonin ε, Leucomelone and Betulinan A
Authors: Deb Arghya , Agasti Soumitra , Saboo Tapish , Maiti Debabrata
Published: March 2014

Biologically and pharmaceutically relevant arylated quinones (Quin‐Ar) have been synthesized via direct CH arylation of a variety of phenols using arylboronic acids. An inexpensive, environmentally friendly iron catalyst, ferric sulphate, Fe2(SO4)3, was employed in this operationally simple and efficient method.

magnified image
Unprecedented Control of Selectivity in Nickel‐Catalyzed Hydrophosphorylation of Alkynes: Efficient Route to Mono‐ and Bisphosphonates
Authors: Khemchyan Levon L. , Ivanova Julia V. , Zalesskiy Sergey S. , Ananikov Valentine P. , Beletskaya Irina P. , Starikova Zoya A.
Published: March 2014

A unique nickel‐based catalytic system was developed where the direction of the hydrophosphorylation reaction can be controlled by varying the catalyst loading. A flexible one‐pot access to vinylmonophosphonates and alkylbisphosphonates was demonstrated using simple starting materials in an atom‐economic reaction without any specific solvents or ligands. Monitoring of the reaction mechanism with joint NMR and MS studies revealed key information about the reaction intermediates. The synthetic scope of the developed catalytic system was explored and the utility of the synthesized products for the fire protection of cotton materials was demonstrated.

magnified image
Symptom perception in healthy menopausal women: Can we predict concordance between subjective and physiological measures of vasomotor symptoms?
Authors: Stefanopoulou Evgenia , Hunter Myra S.
Published: March 2014

Objectives

Perception of physical symptoms is an important factor in medical help‐seeking. We aimed to examine both physiological and subjective measures of a commonly reported physical symptom—vasomotor symptoms (hot flushes and night sweats; HF/NS), and to investigate factors that might influence symptom perception, that is, concordance, over‐reporting, and under‐reporting of symptoms in healthy menopausal women.

Methods

One hundred and forty women completed questionnaires assessing depressed mood, anxiety, stress, somatic symptoms, beliefs about HF/NS, and somatic amplification. Subjective and objective (24‐h sternal skin conductance) measurements of HF/NS were obtained to assess concordance.

Results

Thirty‐seven percent of HF/NS were concordant while 47 and 16 % were under‐reported and over‐reported, respectively. Depressed mood, anxiety, somatic symptoms, and negative beliefs about HF/NS were associated with (higher) concordance, (less) under‐, or (more) over‐reporting. Negative beliefs about night sweats and sleep were the strongest predictors of concordance, whereas additional somatic symptoms and smoking predicted over‐reporting.

Conclusions

Just over one third of physiologically recorded HF/NS were perceived as hot flushes; under‐reporting of symptoms was more common than over‐reporting. Interestingly, women who were more accurate in detecting physiological HF/NS tended to report more psychological and somatic symptoms and negative beliefs about HF/NS. Both measures should be included as outcomes of clinical trials. Am. J. Hum. Biol. 26:389–394, 2014. © 2014 Wiley Periodicals, Inc.
DEPDC5 mutations in genetic focal epilepsies of childhood
Authors: Lal Dennis , Reinthaler Eva M. , Schubert Julian , Muhle Hiltrud , Riesch Erik , Kluger Gerhard , Jabbari Kamel , Kawalia Amit , Bäumel Christine , Holthausen Hans , Hahn Andreas , Feucht Martha , Neophytou Birgit , Haberlandt Edda , Becker Felicitas , Altmüller Janine , Thiele Holger , Lemke Johannes R. , Lerche Holger , Nürnberg Peter , Sander Thomas , Weber Yvonne , Zimprich Fritz , Neubauer Bernd A.
Published: March 2014

Recent studies reported DEPDC5 loss‐of‐function mutations in different focal epilepsy syndromes. Here we identified 1 predicted truncation and 2 missense mutations in 3 children with rolandic epilepsy (3 of 207). In addition, we identified 3 families with unclassified focal childhood epilepsies carrying predicted truncating DEPDC5 mutations (3 of 82). The detected variants were all novel, inherited, and present in all tested affected (n = 11) and in 7 unaffected family members, indicating low penetrance. Our findings extend the phenotypic spectrum associated with mutations in DEPDC5 and suggest that rolandic epilepsy, albeit rarely, and other nonlesional childhood epilepsies are among the associated syndromes. Ann Neurol 2014;75:788–792
Analyse von Protease‐Inhibitor‐Interaktionen unter Nutzung evolvierbarer tricyclischer Microviridine
Authors: Weiz Annika R. , Ishida Keishi , Quitterer Felix , Meyer Sabine , Kehr Jan‐Christoph , Müller Kristian M. , Groll Michael , Hertweck Christian , Dittmann Elke
Published: March 2014

Ein wichtiges Ziel in der therapeutischen Chemie ist das Verständnis und die Kontrolle von proteolytischen Prozessen. Unter den proteaseinhibierenden Naturstoffen nehmen Microviridine eine Sonderstellung ein. Microviridine sind ribosomal erzeugte und posttranslational modifizierte Peptide, die zu einer einzigartigen Struktur mit käfigartiger Gestalt prozessiert werden. Hier beschreiben wir einen kombinierten Ansatz aus rationaler und randomisierter Mutagenese, der grundlegende Erkenntnisse über die Bestandteile der Microviridinstruktur liefert, die zur Selektivität beitragen. Die aktive Variante Microviridin J wurde mit Trypsin kokristallisiert. Dabei wird erstmals die dreidimensionale Struktur von Microviridinen demonstriert und die Art der Inhibierung dargestellt.
Construction of Mesoporous Frameworks with Vanadoborate Clusters
Authors: Chen Hong , Yu Zheng‐Bao , Bacsik Zoltán , Zhao Huishuang , Yao Qingxia , Sun Junliang
Published: March 2014

A new porous vanadoborate was synthesized by employing the scale chemistry theory with the vanadoborate cluster V10B28. The twofold interpenetrated lvt network was assembled with zinc‐containing elliptical vanadoborate clusters and Zn polyhedra. The single lvt framework contains a three‐dimensional 38×38×20 ring channel system with the pore size (24.7×12.7 Å) reaching the mesoscale, thus indicating the possibility of constructing 3D ordered mesopores with vanadoborate clusters. The porosity of the SUT‐7 structure was confirmed by CO2 adsorption of the as‐synthesized materials.
Ein enantiomerenreines metallosupramolekulares Pd4L8‐Aggregat mit neuartigem Strukturmotiv: Bildung durch einen Anionen‐Templateffekt
Authors: Klein Christoph , Gütz Christoph , Bogner Maximilian , Topić Filip , Rissanen Kari , Lützen Arne
Published: March 2014

Ein enantiomerenreiner Bis(3‐pyridyl)‐Ligand 1 auf der Basis eines BINOL‐Gerüsts bildet mit tetravalenten PdII‐Ionen einen homochiralen [Pd4(1)8]‐Komplex. Zwei Tetrafluoroborationen dienen dabei als Template für die Bildung dieses Aggegates und werden in zwei periphere Kavitäten eingeschlossen. Die dadurch resultierende Struktur repräsentiert ein neues Strukturmotiv für diese Sorte von metallosupramolekularen Assemblaten, in dem die vier Palladiumionen in einer verzerrt tetraedrischen Anordnung zu finden sind. Dies zwingt den Liganden 1, zwei verschiedene Konformationen in dem Aggregat einzunehmen. Beide Phänomene sind einzigartig und führen überdies zur Bildung einer dreidimensionalen Struktur, die noch über eine weitere, chirale und hydrophile zentrale Kavität verfügt.
Cationic Chains of Phosphanyl‐ and Arsanylboranes
Authors: Marquardt Christian , Thoms Christine , Stauber Andreas , Balázs Gábor , Bodensteiner Michael , Scheer Manfred
Published: March 2014

Whilst catena‐phosphorus cations have been intensively studied in the last years, mixed Group 13/15 element cationic chains have not yet been reported. Reaction of the pnictogenboranes H2EBH2⋅NMe3 (E=P, As) with monohalideboranes lead to the cationic chain compounds [Me3N⋅BH2EH2BH2⋅NMe3][X] (E=P, As; X=AlCl4, I) and [Me3N⋅BH2PH2BH2PH2BH2⋅NMe3][X] (X=I, VCl4(thf)2), respectively. All of the compounds have been characterized by X‐ray structure analysis, NMR spectroscopy, IR spectroscopy, and mass spectrometry. DFT calculations elucidate the reaction pathway, the high thermodynamic stability, the charge distribution within the chain and confirm the observed solid‐state structures.
Highly Enantioselective Kinetic Resolution of Axially Chiral BINAM Derivatives Catalyzed by a Brønsted Acid
Authors: Cheng Dao‐Juan , Yan Liang , Tian Shi‐Kai , Wu Ming‐Yue , Wang Lu‐Xin , Fan Zi‐Li , Zheng Sheng‐Cai , Liu Xin‐Yuan , Tan Bin
Published: March 2014

A highly efficient strategy for the kinetic resolution of axially chiral BINAM derivatives involving a chiral Brønsted acid‐catalyzed imine formation and transfer hydrogenation cascade process was developed. The kinetic resolution provides a convenient route to chiral BINAM derivatives in high yields with excellent enantioselectivities.
Selective Host–Guest Interactions of a Transformable Coordination Capsule/Tube with Fullerenes
Authors: Kishi Norifumi , Akita Munetaka , Yoshizawa Michito
Published: March 2014

An M2L4 coordination capsule or an M2L2 coordination tube was selectively formed by the combination of HgII hinges and bent bispyridine ligands. The two structures reversibly interconvert at room temperature in response to modulation of the metal‐to‐ligand ratio and exhibit different host–guest interaction behavior. The capsule alone encapsulates large spherical molecules, fullerenes C60 and C70, and the bound guests are released upon capsule‐to‐tube transformation by the simple addition of metal ions.
Confining Phosphanes Derived from Cyclodextrins for Efficient Regio‐ and Enantioselective Hydroformylation
Authors: Jouffroy Matthieu , Gramage‐Doria Rafael , Armspach Dominique , Sémeril David , Oberhauser Werner , Matt Dominique , Toupet Loic
Published: March 2014

Two confining phosphane ligands derived from either α‐ or β‐cyclodextrin produce singly PIII‐ligated metal complexes with unusual coordination spheres. High‐pressure NMR studies have revealed that rhodium hydride complexes of the same type are also formed under hydroformylation conditions. This unique feature strongly favors the formation of the branched aldehyde at the expense of the linear one with high enantioselectivity in the rhodium‐catalyzed hydroformylation of styrene.
Click‐Assembled, Oxygen‐Sensing Nanoconjugates for Depth‐Resolved, Near‐Infrared Imaging in a 3 D Cancer Model
Authors: Nichols Alexander J. , Roussakis Emmanuel , Klein Oliver J. , Evans Conor L.
Published: March 2014

Hypoxia is an important contributing factor to the development of drug‐resistant cancer, yet few nonperturbative tools exist for studying oxygenation in tissues. While progress has been made in the development of chemical probes for optical oxygen mapping, penetration of such molecules into poorly perfused or avascular tumor regions remains problematic. A click‐assembled oxygen‐sensing (CAOS) nanoconjugate is reported and its properties demonstrated in an in vitro 3D spheroid cancer model. The synthesis relies on the sequential click‐based ligation of poly(amidoamine)‐like subunits for rapid assembly. Near‐infrared confocal phosphorescence microscopy was used to demonstrate the ability of the CAOS nanoconjugates to penetrate hundreds of micrometers into spheroids within hours and to show their sensitivity to oxygen changes throughout the nodule. This proof‐of‐concept study demonstrates a modular approach that is readily extensible to a wide variety of oxygen and cellular sensors for depth‐resolved imaging in tissue and tissue models.
Research on the preparation and antibacterial properties of 2‐N‐thiosemicarbazide‐6‐O‐hydroxypropyl chitosan membranes with iodine
Authors: Sai Mingze , Zhong Shiliang , Tang Yang , Ma Wentao , Sun Yangang , Ding Derun
Published: March 2014

The 2‐N‐thiosemicarbazide‐6‐O‐hydroxypropyl chitosan (ATU‐HPCS) was prepared by chitosan grafted hydroxypropyl and thiosemicarbazide through the method of “amino protection‐graft‐deprotection,” while the ATU‐HPCS gel membranes were obtained from gelatin and polyvinyl pyrrolidone as additives, and the ATU‐HPCS membranes with iodine (ATU‐HPCS‐I2‐M) were prepared by adding the ethanol solution of iodine in the ATU‐HPCS gel membranes. The ATU‐HPCS‐I2‐M were characterized to evaluate their potential applications as antibacterial materials. The iodine releasing rule of ATU‐HPCS‐I2‐M showed a sustained‐release effect of iodine, the maximum emission was approximately 0.80%. The inhibition zone diameters of ATU‐HPCS‐I2‐M against Staphylococcus aureus (as Gram‐positive bacteria) and Escherichia coli (as Gram‐negative bacteria) were both greater than 15 mm, it demonstrated significant antibacterial activity compared with the ATU‐HPCS gel membranes. The double effects of the biocompatibility of chitosan and the sustained‐release of iodine provided an ideal healing environment for wound surface. These properties have made ATU‐HPCS‐I2‐M highly potential as a novel natural macromolecule antimicrobial material preventing the bacteria from burns, surgery wounds, etc. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40535.
A novel adsorbent obtained by caging activated carbon by konjac glucomannan gel for elimination of organic compounds
Authors: Dai Yingjie , Yan Hong , Zhang Binbin , Wu Wenting , Yang Liqiong , Li Shufeng , Li Wenbin , Li Hongtao , Yan Lilong , Shan Dexin , Feng Yujie , Terui Norifumi , Tanaka Shunitz
Published: March 2014

In this study, the adsorptive ability of the konjac glucomannan gel containing activated carbon (KGMG–AC) was investigated by measuring the removal of several organic compounds with different charges, such as nitrobenzene (NB), methylene blue (MB), and rose bengale (RB). The physical and chemical properties, adsorption dynamics, adsorption isotherms, and the effect of pH of the adsorbents were compared with those of a commercially available powdered activated carbon (AC). The results of the present study indicate that the removal ratio of NB, MB, and RB onto KGMG–AC was slightly higher than that of the AC. The adsorption equilibrium constant (KL) value (0.02 L/mg) of KGMG–AC for NB was similar to that of AC (0.03 L/mg). However, the saturated adsorption amount (Q0) of KGMG–AC (368 mg/g) for NB was slightly larger than that of AC (354 mg/g). The saturated adsorption amounts of MB and RB on KGMG–AC were 302 and 259 mg/g, respectively. On the other hand, a high molecular weight humic acid was not adsorbed by KGMG–AC. Thus, entrapping AC into KGMG resulted in the selective adsorption. Therefore, this study could show that KGMG–AC was a new environmental friendly adsorbent that can be easily prepared, used, and recovered in environments. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2014,131, 40542.
Recent advances on polymer‐stabilized blue phase liquid crystal materials and devices
Authors: Chen Yuan , Wu Shin‐Tson
Published: March 2014

Polymer‐stabilized blue phase liquid crystals (PS‐BPLC) have become an increasingly important technology trend for information display and photonics applications. BPLCs exhibit several attractive features, such as reasonably wide temperature range, submillisecond gray‐to‐gray response time, no need for alignment layer, optically isotropic voltage‐off state, and large cell gap tolerance. However, some bottlenecks such as high operation voltage, hysteresis, residual birefringence, charging issues due to the large capacitance, and relatively low transmittance remain to be overcome before their widespread applications can be realized. Recent progress on BPLC materials and devices has shown great promise. To realize the electro‐optic effect of PS‐BPLC, two driving modes: in‐plane switching and vertical field switching mode, have been developed. The material system of PS‐BPLC, including nematic LC host, chiral dopant, and polymer network, are discussed. Each component plays an essential role affecting the stability and electro‐optic properties of PS‐BPLC. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40556.
Disseminating research with web CV hyperlinks
Authors: Kousha Kayvan , Thelwall Mike
Published: March 2014

Some curricula vitae (web CVs) of academics on the web, including homepages and publication lists, link to open‐access (OA) articles, resources, abstracts in publishers' websites, or academic discussions, helping to disseminate research. To assess how common such practices are and whether they vary by discipline, gender, and country, the authors conducted a large‐scale e‐mail survey of astronomy and astrophysics, public health, environmental engineering, and philosophy across 15 European countries and analyzed hyperlinks from web CVs of academics. About 60% of the 2,154 survey responses reported having a web CV or something similar, and there were differences between disciplines, genders, and countries. A follow‐up outlink analysis of 2,700 web CVs found that a third had at least one outlink to an OA target, typically a public eprint archive or an individual self‐archived file. This proportion was considerably higher in astronomy (48%) and philosophy (37%) than in environmental engineering (29%) and public health (21%). There were also differences in linking to publishers' websites, resources, and discussions. Perhaps most important, however, the amount of linking to OA publications seems to be much lower than allowed by publishers and journals, suggesting that many opportunities for disseminating full‐text research online are being missed, especially in disciplines without established repositories. Moreover, few academics seem to be exploiting their CVs to link to discussions, resources, or article abstracts, which seems to be another missed opportunity for publicizing research.
User engagement in online News: Under the scope of sentiment, interest, affect, and gaze
Authors: Arapakis Ioannis , Lalmas Mounia , Cambazoglu B. Barla , Marcos Mari‐Carmen , Jose Joemon M.
Published: March 2014

Online content providers, such as news portals and social media platforms, constantly seek new ways to attract large shares of online attention by keeping their users engaged. A common challenge is to identify which aspects of online interaction influence user engagement the most. In this article, through an analysis of a news article collection obtained from Yahoo News US, we demonstrate that news articles exhibit considerable variation in terms of the sentimentality and polarity of their content, depending on factors such as news provider and genre. Moreover, through a laboratory study, we observe the effect of sentimentality and polarity of news and comments on a set of subjective and objective measures of engagement. In particular, we show that attention, affect, and gaze differ across news of varying interestingness. As part of our study, we also explore methods that exploit the sentiments expressed in user comments to reorder the lists of comments displayed in news pages. Our results indicate that user engagement can be anticipated predicted if we account for the sentimentality and polarity of the content as well as other factors that drive attention and inspire human curiosity.
Vicinal Difunctionalization of Alkenes with Iodine(III) Reagents and Catalysts
Authors: Romero R. Martín , Wöste Thorsten H. , Muñiz Kilian
Published: March 2014

Hypervalent iodine(III) reagents have been known for over a century, and their reaction profile is still actively investigated. Recent years have seen impressive improvements in the area of alkene difunctionalization reactions, where new methodologies have become available. Especially chiral non‐racemic hypervalent iodine(III) reagents and catalysts have emerged as versatile tools for the realization of important enantioselective transformations.
Druckstrebentragfähigkeit von vorgespannten UHPFRC‐Hohlkästen unter Torsion und kombinierter Beanspruchung
Authors: Oettel Vincent , Empelmann Martin
Published: March 2014

Aufgrund der hohen Druckfestigkeit von ultrahochfestem Faserbeton (UHPFRC) lassen sich sehr dünnwandige und innovative Bauelemente herstellen. Durch eine Vorfabrikation von transportgerechten und gewichtsoptimierten Segmenten, die später auf der Baustelle zu komplexen Bauteilen, wie z.B. Segmentbrücken, Fertigteiltürmen oder Fertigteilmasten zusammengespannt werden, könnten neue Anwendungsfelder für Betonbauteile erschlossen werden. Neben der Einwirkung aus Biegung und Querkraft treten in der späteren Nutzung auch Torsionsbeanspruchungen auf. Am iBMB, Fachgebiet Massivbau der TU Braunschweig, wurden experimentelle und theoretische Untersuchungen zur Druckstrebentragfähigkeit von monolithischen und segmentären extern vorgespannten Balken mit Hohlkastenquerschnitten aus UHPFRC unter Torsion sowie unter kombinierter Biege‐, Querkraft‐ und Torsionsbeanspruchung durchgeführt. Auf Basis der Versuchsergebnisse und unter Beachtung der Rechenansätze für normal‐ und hochfeste Betone wurden bestehende Bemessungsmodelle zur Beschreibung der Druckstrebentragfähigkeit für UHPFRC erweitert.

Bearing capacity of the compression strut of prestressed UHPFRC box girders under torsion and combined loading

Due to the high compressive strength of ultra‐high performance fiber reinforced concrete (UHPFRC) thin‐walled and innovative components can be produced. In order to gain new fields of application for concrete elements it would be useful to prefabricate weight‐optimized and transportable segments, which could be mounted to complex components such as segmental bridges, precast towers or precast poles directly on site. As such components are not only stressed by bending and shear, but also torsion, the iBMB, Department of Concrete Structures of the TU Braunschweig, has conducted experimental and theoretical research works on the bearing capacity of the concrete compression strut of monolithic and segmental externally prestressed UHPFRC box girders under torsion and combined loading of bending, shear and torsion. Based on the experimental results and the approaches of normal‐ and high‐strength concrete the existing design models have been extended to describe the bearing capacity of UHPFRC compression struts.
The role of microemulsions in lipase‐catalyzed hydrolysis reactions
Authors: Lopez Francesco , Cinelli Giuseppe , Colella Matilde , De Leonardis Antonella , Palazzo Gerardo , Ambrosone Luigi
Published: March 2014

The kinetics of the p‐nitrophenyl butyrate hydrolysis reaction, catalyzed by Candida rugosa lipase in the water‐in‐oil microemulsion cetyltrimethylammonium bromide/water/pentanol/hexane, was investigated. The results described in the present manuscript reveal two peculiar characteristics of the reaction: (i) the initial rate of hydrolysis is very fast and (ii) by decreasing the water content of the microemulsion, the reaction rate approaches the typical behavior of reactions performed in aqueous solution. In particular, for microemulsion systems with a high water content, the end points of the reactions are dictated by the shape stability of the microemulsion. For these systems, our methodological approach shows that the process follows a second‐order kinetics equation, indicative of the dual role played by water, which is involved both as a component of the microemulsion, i.e., relevant for the microemulsion stability and as a reagent of the hydrolysis reaction. In contrast, for microemulsions containing a small amount of water, after the hydrolysis reaction the system seems to fall in the no existence range of the microemulsion. Accordingly, the kinetics results are more complex: in the initial stage, the reaction follows a zero‐order kinetics equation, while for longer reaction times a first‐order kinetics equation fits the experimental data, as would be expected for an enzymatic reaction in a homogeneous system. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:360–366, 2014
The role of albumin and PPAR‐α in differentiation‐dependent change of fatty acid profile during differentiation of mesenchymal stem cells to hepatocyte‐like cells
Authors: Esmaeli Shahnaz , Allameh Abdolamir , Soleimani Masoud , Rahbarizadeh Fatemeh , Frouzandeh‐Moghadam Mehdi
Published: March 2014

Differentiation of mesenchymal stem cells (MSCs) to hepatocyte‐like cells is associated with morphological and biological changes. In this study, the effect of hepatogenic differentiation on fatty acid profile and the expression of proliferator‐activated receptors‐α (PPAR‐α) have been studied. For this purpose, MSCs isolated from human umbilical cord were differentiated into hepatocyte‐like cells on selective culture media. The morphological and biochemical changes, PPAR‐α expression and reactive oxygen species (ROS) levels were studied during the differentiation process. Besides, the cells were processed to determine changes in fatty acid profile using gas chromatography analysis. The results showed that hepatic differentiation of the MSCs is associated with a decrease in major polyunsaturated fatty acids in mature hepatocytes, whereas there was an increase in the saturated fatty acid (SFA) levels during hepatocyte maturation. The differentiation‐dependent shift in the ratio of SFA/USFA was associated with changes in albumin and PPAR‐α expression, whereas changes in fatty acid profile were independent of ROS production and lipid peroxidation in differentiating cells. In conclusion, these data may suggest that hepatocyte formation during the stem cell differentiation is associated with a shift in the fatty acid profile that is probably a normal phenomenon in hepatogenic differentiation of the MSCs. Copyright © 2014 John Wiley & Sons, Ltd.
Tailoring the Cooperative Acid–Base Effects in Silica‐Supported Amine Catalysts: Applications in the Continuous Gas‐Phase Self‐Condensation of n‐Butanal
Authors: Shylesh Sankaranarayanapillai , Hanna David , Gomes Joseph , Krishna Siddarth , Canlas Christian G. , Head‐Gordon Martin , Bell Alexis T.
Published: March 2014

A highly efficient solid‐base organocatalyst for the gas‐phase aldol self‐condensation of n‐butanal to 2‐ethylhexenal was developed by grafting site‐isolated amines on tailored silica surfaces. The catalytic activity depends largely on the nature of amine species, the surface concentration of amine and silanol groups, and the spatial separation between the silanol and amine groups. In situ FTIR measurements demonstrated that the formation of nucleophilic enamines leads to the enhanced catalytic activity of secondary amine catalysts, whereas the formation of imines (stable up to 473 K) leads to the low activity observed for silica‐supported primary amines. Blocking the silanol groups on the silica support by silylation or cofeeding water into the reaction stream drastically decreased the reaction rates, demonstrating that weaker acidic silanol groups participate cooperatively with the amine groups to catalyze the condensation reaction. This work demonstrates that the spatial separation of the weakly acidic silanols and amines can be tuned by the controlled dehydration of the supporting silica and by varying the linker length of the amine organosilane precursor used to graft the amine to the support surface. A mechanism for aldol condensation was proposed and then analyzed by DFT calculations. DFT analysis of the reaction pathway suggested that the rate‐limiting step in aldol condensation is carboncarbon bond formation, which is consistent with the observed kinetics. The calculated apparent activation barrier agrees reasonably with that measured experimentally.
Electrostatic and Non‐covalent Interactions in Dicationic Imidazolium–Sulfonium Salts with Mixed Anions
Authors: Fei Zhaofu , Zhu Dun‐Ru , Yan Ning , Scopelliti Rosario , Katsuba Sergey A. , Laurenczy Gabor , Chisholm Danielle M. , McIndoe J. Scott , Seddon Kenneth R. , Dyson Paul J.
Published: March 2014

A series of thioether‐functionalised imidazolium salts have been prepared and characterized. Subsequent reaction of the thioether‐functionalised imidazolium salts with iodomethane affords imidazolium–sulfonium salts composed of doubly charged cations and two different anions. Imidazolium–sulfonium salts containing a single anion type are obtained either by a solvent extraction method or by anion exchange. The imidazolium–sulfonium salts undergo a methyl‐transfer reaction on exposure to water, giving rise to a new, singly charged imidazolium salt with iodide introduced at the 2‐position of the imidazolium ring. Crystal structures of some of the imidazolium–sulfonium salts were determined by X‐ray crystallography providing the topology of the interactions between the dications and the anions. Electrospray ionization mass spectrometry and quantum‐chemical calculations were used to rationalise the relative strength of these interactions.
Solvent‐Dependent Self‐Assembly Behaviour and Speciation Control of Pd6L8 Metallo‐supramolecular Cages
Authors: Henkelis James J. , Fisher Julie , Warriner Stuart L. , Hardie Michaele J.
Published: March 2014

The C3‐symmetric chiral propylated host‐type ligands (±)‐tris(isonicotinoyl)‐tris(propyl)‐cyclotricatechylene (L1) and (±)‐tris(4‐pyridyl‐4‐benzoxy)‐tris(propyl)‐cyclotricatechylene (L2) self‐assemble with PdII into [Pd6L8]12+ metallo‐cages that resemble a stella octangula. The self‐assembly of the [Pd6(L1)8]12+ cage is solvent‐dependent; broad NMR resonances and a disordered crystal structure indicate no chiral self‐sorting of the ligand enantiomers in DMSO solution, but sharp NMR resonances occur in MeCN or MeNO2. The [Pd6(L1)8]12+ cage is observed to be less favourable in the presence of additional ligand, than is its counterpart, where L=(±)‐tris(isonicotinoyl)cyclotriguaiacylene (L1 a). The stoichiometry of reactant mixtures and chemical triggers can be used to control formation of mixtures of homoleptic or heteroleptic [Pd6L8]12+ metallo‐cages where L=L1 and L1 a.
SiO2/TiO2 Hollow Nanoparticles Decorated with Ag Nanoparticles: Enhanced Visible Light Absorption and Improved Light Scattering in Dye‐Sensitized Solar Cells
Authors: Hwang Sun Hye , Shin Dong Hoon , Yun Juyoung , Kim Chanhoi , Choi Moonjung , Jang Jyongsik
Published: March 2014

Hollow SiO2/TiO2 nanoparticles decorated with Ag nanoparticles (NPs) of controlled size (Ag@HNPs) were fabricated in order to enhance visible‐light absorption and improve light scattering in dye‐sensitized solar cells (DSSCs). They exhibited localized surface plasmon resonance (LSPR) and the LSPR effects were significantly influenced by the size of the Ag NPs. The absorption peak of the LSPR band dramatically increased with increasing Ag NP size. The LSPR of the large Ag NPs mainly increased the light absorption at short wavelengths, whereas the scattering from the SiO2/TiO2 HNPs improved the light absorption at long wavelengths. This enabled the working electrode to use the full solar spectrum. Furthermore, the SiO2 layer thickness was adjusted to maximize the LSPR from the Ag NPs and avoid corrosion of the Ag NPs by the electrolyte. Importantly, the power conversion efficiency (PCE) increased from 7.1 % with purely TiO2‐based DSSCs to 8.1 % with HNP‐based DSSCs, which is an approximately 12 % enhancement and can be attributed to greater light scattering. Furthermore, the PCEs of Ag@HNP‐based DSSCs were 11 % higher (8.1 vs. 9.0 %) than the bare‐HNP‐based DSSCs, which can be attributed to LSPR. Together, the PCE of Ag@HNP‐based DSSCs improved by a total of 27 %, from 7.1 to 9.0 %, due to these two effects. This comparative research will offer guidance in the design of multifunctional nanomaterials and the optimization of solar‐cell performance.
Acetylcholine‐Triggered Cargo Release from Supramolecular Nanovalves Based on Different Macrocyclic Receptors
Authors: Zhou Yue , Tan Li‐Li , Li Qing‐Lan , Qiu Xi‐Long , Qi Ai‐Di , Tao Yanchun , Yang Ying‐Wei
Published: March 2014

Acetylcholine (ACh), a neurotransmitter located in cholinergic synapses, can trigger cargo release from mesoporous silica nanoparticles equipped with calixarene‐ or pillarene‐based nanovalves by removing macrocycles from the stalk components. The amount and speed of cargo release can be controlled by varying the concentration of ACh in solution or changing the type of gating macrocycle. Although this proof‐of‐concept study is far from a real‐life application, it provides a possible route to treat diseases related to the central nervous system.
Synthesis of Indazoles and Azaindazoles by Intramolecular Aerobic Oxidative CN Coupling under Transition‐Metal‐Free Conditions
Authors: Hu Jiantao , Xu Huacheng , Nie Pengju , Xie Xiaobo , Nie Zongxiu , Rao Yu
Published: March 2014

A transition‐metal‐free oxidative CN coupling method has been developed for the synthesis of 1H‐azaindazoles and 1H‐indazoles from easily accessible hydrazones. The procedure uses TEMPO, a basic additive, and dioxygen gas as the terminal oxidant. This reaction demonstrates better reactivity, functional group tolerance, and broader scope than comparable metal catalyzed reactions.
HPLC‐Fluorescence Method for the Enantioselective Analysis of Propranolol in Rat Serum Using Immobilized Polysaccharide‐Based Chiral Stationary Phase
Authors: Alanazi Amer M. , Hefnawy Mohamed M. , AL‐Majed Abdulrahman A. , AL‐ Suwailem Aymen K. , Kassem Mohamed G. , Mostafa Gamal A. , Attia Sabry M. , Khedr Mohammed M.
Published: March 2014

A stereoselective high‐performance liquid chromatographic (HPLC) method was developed and validated to determine S‐(−)‐ and R‐(+)‐propranolol in rat serum. Enantiomeric resolution was achieved on cellulose tris(3,5‐dimethylphenylcarbamate) immobilized onto spherical porous silica chiral stationary phase (CSP) known as Chiralpak IB. A simple analytical method was validated using a mobile phase consisted of n‐hexane‐ethanol‐triethylamine (95:5:0.4%, v/v/v) at a flow rate of 0.6 mL min‐1 and fluorescence detection set at excitation/emission wavelengths 290/375 nm. The calibration curves were linear over the range of 10–400 ng mL‐1 (R = 0.999) for each enantiomer with a detection limit of 3 ng mL‐1. The proposed method was validated in compliance with ICH guidelines in terms of linearity, accuracy, precision, limits of detection and quantitation, and other aspects of analytical validation. Actual quantification could be made for propranolol isomers in serum obtained from rats that had been intraperitoneally (i.p.) administered a single dose of the drug. The proposed method established in this study is simple and sensitive enough to be adopted in the fields of clinical and forensic toxicology. Molecular modeling studies including energy minimization and docking studies were first performed to illustrate the mechanism by which the active enantiomer binds to the β‐adrenergic receptor and second to find a suitable interpretation of how both enantiomers are interacting with cellulose tris(3,5‐dimethylphenylcarbamate) CSP during the process of resolution. The latter interaction was demonstrated by calculating the binding affinities and interaction distances between propranolol enantiomers and chiral selector. Chirality 26:194–199, 2014. © 2014 Wiley Periodicals, Inc.
Optimization Study: Biological Removal of Inorganic Nitrogen along with Chemical Oxygen Demand from Wastewater Using Response Surface Methodology
Authors: Mohanty Ayusman , Ray Sanak , Yadav Asheesh Kumar , Chaudhury G. Roy
Published: March 2014

A comparative optimization study using response surface methodology (RSM) was carried out for biological removal of various inorganic N–NH3 sources (NH4OH, (NH4)2SO4, NH4NO3) along with chemical oxygen demand (COD; glucose: C6H12O6) from synthetic wastewater and consequently minimizing the N–N2O emission. Heterotrophic biomass conversion (HBC) process was used for wastewater treatment. Central composite design (CCD) method was used to optimize various experimental parameters using RSM. During the experiment biomass (total volatile suspended solids) was kept constant, while varying nitrogen and carbon concentration, respectively. Alkalinity consumption results in pH decrease during the HBC process. N–NH3 and COD depletion rates were higher in NH4OH in comparison to the other two nitrogen sources. Analyses of variance observed highly significant differences. Models obtained through CCD method were checked and tested via experiments and statistics. Having optimum value, i.e., 210 mg/L N–NH3, 2.90 g/L COD and 38 h; higher COD (94.1%) and N–NH3 (82.72%) removal was observed in (NH4)2SO4 and NH4OH. Higher desirability factor was obtained in NH4OH.
Development and Screening of a Series of Antibody‐Conjugated and Silica‐Coated Iron Oxide Nanoparticles for Targeting the Prostate‐Specific Membrane Antigen
Authors: Mukherjee Amarnath , Darlington Thomas , Baldwin Richard , Holz Charles , Olson Sage , Kulkarni Prakash , DeWeese Theodore L. , Getzenberg Robert H. , Ivkov Robert , Lupold Shawn E.
Published: March 2014

The prostate‐specific membrane antigen (PSMA) is an established target for the delivery of cancer therapeutic and imaging agents due to its high expression on the surface of prostate cancer cells and within the neovasculature of other solid tumors. Here, we describe the synthesis and screening of antibody‐conjugated silica‐coated iron oxide nanoparticles for PSMA‐specific cell targeting. The humanized anti‐PSMA antibody, HuJ591, was conjugated to a series of nanoparticles with varying densities of polyethylene glycol and primary amine groups. Customized assays utilizing iron spectral absorbance and enzyme‐linked immunoassay (ELISA) were developed to screen microgram quantities of nanoparticle formulations for immunoreactivity and cell targeting ability. Antibody and PSMA‐specific targeting of the optimized nanoparticle was evaluated using an isogenic PSMA‐positive and PSMA‐negative cell line pair. Specific nanoparticle targeting was confirmed by iron quantification with inductively coupled plasma mass spectrometry (ICP‐MS). These methods and nanoparticles support the promise of targeted theranostic agents for future treatment of prostate and other cancers.
Can we change the past for colorectal cancer patients and how do we move forward?
Authors: Jeon Justin Y. , Meyerhardt Jeffrey A.
Published: March 2014

Many lifestyle factors, such as diet, physical activity, smoking, alcohol consumption, and adiposity, are modifiable, and there is great interest whether changing these factors could have potential preventive benefits in those without colorectal cancer and adjuvant benefits for those with the disease. A recent study demonstrates that individual exposures and healthier composite lifestyle are associated with improved overall and/or cardiovascular mortality, which highlights to clinicians that colorectal cancer survivors are at risk for other comorbidities that are associated with increased mortality.
The prediction of malignant risk in the category “atypia of undetermined significance/follicular lesion of undetermined significance” of the Bethesda System for Reporting Thyroid Cytopathology using subcategorization and BRAF mutation results
Authors: Hyeon Jiyeon , Ahn Soomin , Shin Jung Hee , Oh Young Lyun
Published: March 2014

BACKGROUND

The “atypia of undetermined significance/follicular lesion of undetermined significance” (AUS/FLUS) category in the Bethesda System for Reporting Thyroid Cytopathology is a heterogeneous category of cases that are not clearly benign or malignant.

METHODS

We conducted an analysis of cytologic and histologic evaluations of thyroid nodules that had been interpreted as AUS/FLUS on fine‐needle aspiration (FNA) at a single institution from April 2011 to April 2012. Those cases were classified into 2 subgroups according to the predominance of nuclear atypia (AUS) or microfollicular architecture (FLUS). In addition, for a number of these cases, BRAF gene mutation analyses were performed.

RESULTS

Of 6402 thyroid FNAs performed, 431 cases were diagnosed as AUS and 120 as FLUS. Follow‐up cytologic or histologic outcome data were available for 315 AUS cases and 73 FLUS cases. Among AUS cases, 52.7% were malignant on repeat FNA or histologic diagnosis. In contrast, for FLUS, 6.8% were malignant on repeat FNA or histologic diagnosis. Among AUS/FLUS cases, 147 had adequate BRAF mutation analysis, which accompanied the histologic diagnosis. BRAF mutations were found in 87 AUS cases, 86 of which were papillary carcinoma. In contrast, there was only 1 case of BRAF mutation in FLUS. Correlating molecular results with histologic outcome revealed a 98.9% cancer probability for AUS cases with BRAF mutation.

CONCLUSIONS

The AUS subcategory indicates a higher risk of malignancy than the FLUS subcategory. Furthermore, BRAF molecular testing is helpful in stratifying the malignant risk of AUS cases into high‐risk and low‐risk groups. Cancer (Cancer Cytopathol) 2014;122:368–376. © 2014 American Cancer Society.
1,2,4‐Oxadiazole‐Based Bent‐Core Liquid Crystals with Cybotactic Nematic Phases
Authors: Shanker Govindaswamy , Prehm Marko , Nagaraj Mamatha , Vij Jagdish K. , Weyland Marvin , Eremin Alexey , Tschierske Carsten
Published: March 2014

Several series of bent‐core mesogens derived from 3,5‐diphenyl‐1,2,4‐oxadiazole with or without lateral groups and with different length terminal chains at both ends, and polycatenar molecules with three to six alkoxy chains are synthesized and their mesomorphic behaviour is investigated by polarizing microscopy, differential scanning calorimetry, X‐ray diffraction (XRD), dielectric, electro‐optical and second‐harmonic generation (SHG) experiments. Most compounds exhibit broad regions of skewed cybotactic nematic (NcybC) and tilted smectic (SmC) phases with a strong tilt of the aromatic cores (up to 63°), but non‐tilted SmA and NcybA phases are also observed for a compound that has only one terminal chain. The XRD patterns of the nematic phases of most of the compounds investigated indicate a 2D periodicity with short correlation length in the magnetically aligned samples. This is of importance for the general interpretation of the small‐angle XRD splitting patterns typically observed for aligned samples of bent‐core nematic phases. In most nematic phases one current peak is observed in the half period of an applied electric field, though no coherent signal is found in the SHG experiments. Based on additional electro‐optical and dielectric results, the nematic phases are considered to be cybotactic nematic phases with local polar order, and show a dielectric reorientation of the polar domains. Only chiral nematic phases (NcybC*), but not blue phases, are obtained for compounds with one or two chiral (3S)‐3,7‐dimethyloctyloxy tail(s).
Sterically Hindered Phthalocyanines for Dye‐Sensitized Solar Cells: Influence of the Distance between the Aromatic Core and the Anchoring Group
Authors: Ragoussi Maria‐Eleni , Yum Jun‐Ho , Chandiran Aravind Kumar , Ince Mine , de la Torre Gema , Grätzel Michael , Nazeeruddin Mohammad K. , Torres Tomás
Published: March 2014

A new phthalocyanine (Pc) bearing bulky peripheral substituents and a carboxylic anchoring group directly attached to the macrocycle has been prepared and used as a sensitizer in DSSCs, reaching 5.57 % power conversion efficiency. In addition, an enhanced performance for the TT40 dye, previously reported by us, was achieved in optimized devices, obtaining a new record efficiency with Pc‐sensitized cells.
CO2 Capture and Conversion with a Multifunctional Polyethyleneimine‐Tethered Iminophosphine Iridium Catalyst/Adsorbent
Authors: McNamara Nicholas D. , Hicks Jason C.
Published: March 2014

Tunable, multifunctional materials able to capture CO2 and subsequently catalyze its conversion to formic acid were synthesized by the modification of branched polyethyleneimine (PEI) with an iminophosphine ligand coordinated to an Ir precatalyst. The molecular weight of the PEI backbone was an important component for material stability and catalytic activity, which were inversely related. The amine functionalities on PEI served three roles: 1) primary amines were used to tether the ligand and precatalyst, 2) amines were used to capture CO2, and 3) amines served as a base for formate stabilization during catalysis. Ligand studies on imine and phosphine based ligands showed that a bidentate iminophosphine ligand resulted in the highest catalytic activity. X‐ray photoelectron spectroscopy revealed that an increase in Ir 4f binding energy led to an increase in catalytic activity, which suggests that the electronics of the metal center play a significant role in catalysis. Catalyst loading studies revealed that there is a critical balance between free amines and ligand–metal sites that must be reached to optimize catalytic activity. Thus, it was found that the CO2 capture and conversion abilities of these materials could be optimized for reaction conditions by tuning the structure of the PEI‐tethered materials.