bluuebunny/crossref_metadata_2025_split huggingface dataset:
Insulating and cooling effects of nasal endoscope sheaths and irrigation
Authors: Craig John , Goyal Parul 
Published: July 2014

BackgroundHeat generated at the tips of nasal endoscopes have been shown to reach temperatures high enough to cause thermal tissue injury. Endoscope sheaths have the potential to minimize the risk of thermal tissue injury. The purpose of this study was to assess the abilities of plastic and metal endoscope sheaths and sheath irrigation to insulate against dangerous scope tip temperatures.MethodsA 4‐mm 0‐degree rigid nasal endoscope was used with light‐emitting diode (LED) and xenon light sources (400‐W LED, 300‐W, and 175‐W xenon) to assess scope tip temperature before and after endoscope sheath placement. Temperatures were assessed again after placement of each sheath, both before and after active saline irrigation. Scope tip temperature was measured using a noncontact infrared thermometer.ResultsThe unsheathed rigid scope tip reached a maximal temperature after 10 minutes at 100% light source intensity. The 400‐W LED and 300‐W xenon sources generated potentially dangerous scope tip temperatures exceeding 42°C, whereas the 175‐W xenon source never generated a maximal temperature over 32.6°C. After placement of plastic and metal sheaths, mean scope tip temperatures were decreased by 2°C (4.8%) and 2.2°C (5.5%), respectively. After active saline irrigation, mean scope tip temperatures were decreased by 5.1°C (12.6%) and 5.2°C (12.8%), respectively.ConclusionWith modern light sources, nasal endoscopes have the potential to reach temperatures that may cause thermal tissue injury. Endoscope sheaths lead to decreases in scope temperatures, and the effect is greater with active irrigation. In addition to improving visualization, endoscope sheaths may decrease the risk of thermal tissue injury.
An All‐Halogen Bonding Rotaxane for Selective Sensing of Halides in Aqueous Media
Authors: Mullaney Benjamin R. , Thompson Amber L. , Beer Paul D. 
Published: July 2014

AbstractThe synthesis and anion binding properties of the first rotaxane host system to bind and sense anions purely through halogen bonding, is described. Through a combination of polarized iodotriazole and iodotriazolium halogen bond donors, a three‐dimensional cavity is created for anion binding. This rotaxane incorporates a luminescent rhenium(I) bipyridyl metal sensor motif within the macrocycle component, thus enabling optical study of the anion binding properties. The rotaxane topology was confirmed by single‐crystal X‐ray structural analysis, demonstrating halogen bonding between the electrophilic iodine atoms and chloride anions. In 50 % H2O/CH3CN solvent mixtures the rotaxane host exhibits strong binding affinity and selectivity for chloride, bromide, and iodide over a range of oxoanions.
Three‐Dimensional Scaffolds of Carbonized Polyacrylonitrile for Bone Tissue Regeneration
Authors: Ryu Seungmi , Lee Choonghyeon , Park Jooyeon , Lee Jun Seop , Kang Seokyung , Seo Young Deok , Jang Jyongsik , Kim Byung‐Soo 
Published: July 2014

AbstractCarbon‐based materials have been extensively studied for stem cell culture. However, difficulties associated with engineering pure carbon materials into 3D scaffolds have hampered applications in tissue engineering and regenerative medicine. Carbonized polyacrylonitrile (cPAN) could be a promising alternative, as cPAN is a highly ordered carbon isomorph that resembles the graphitic structure and can be easily processed into 3D scaffolds. Despite the notable features of cPAN, application of cPAN in tissue engineering and regenerative medicine have not been explored. This study, for the first time, demonstrates the fabrication of microporous 3D scaffolds of cPAN and excellent osteoinductivity of cPAN, suggesting utility of 3D cPAN scaffolds as synthetic bone graft materials. The combination of excellent processability and unique bioactive properties of cPAN may lead to future applications in orthopedic regenerative medicine.
N‐Trifluoromethylthiosaccharin: An Easily Accessible, Shelf‐Stable, Broadly Applicable Trifluoromethylthiolating Reagent
Authors: Xu Chunfa , Ma Bingqing , Shen Qilong 
Published: July 2014

AbstractA new, electrophilic trifluoromethylthiolating reagent, N‐trifluoromethylthiosaccharin, was developed and can be synthesized in two steps from saccharin within 30 minutes. N‐trifluoromethylthiosaccharin is a powerful trifluoromethylthiolating reagent and allows the trifluoromethylthiolation of a variety of nucleophiles such as alcohols, amines, thiols, electron‐rich arenes, aldehydes, ketones, acyclic β‐ketoesters, and alkynes under mild reaction conditions.
Palladium‐Catalyzed Amination of Aryl Sulfides with Anilines
Authors: Sugahara Tomohiro , Murakami Kei , Yorimitsu Hideki , Osuka Atsuhiro 
Published: July 2014

AbstractA combination of a palladium–NHC catalyst and potassium hexamethyldisilazide enables the amination of aryl sulfides with anilines to afford a wide variety of diarylamines. The reaction conditions are versatile enough for the reaction of even bulky ortho‐substituted aryl sulfides. This amination can be applied to the modular synthesis of N‐aryl carbazoles from the corresponding ortho‐bromothioanisoles. As aryl sulfoxides undergo extended Pummerer reactions to afford ortho‐substituted aryl sulfides, the Pummerer products are thus useful substrates for the amination to culminate in efficient syntheses of a 2‐anilinobenzothiophene and an indole as proof‐of‐principle of the utility of the extended Pummerer reaction/amination cascade.
Membrane Deformation by Neolectins with Engineered Glycolipid Binding Sites
Authors: Arnaud Julie , Tröndle Kevin , Claudinon Julie , Audfray Aymeric , Varrot Annabelle , Römer Winfried , Imberty Anne 
Published: July 2014

AbstractLectins are glycan‐binding proteins that are involved in the recognition of glycoconjugates at the cell surface. When binding to glycolipids, multivalent lectins can affect their distribution and alter membrane shapes. Neolectins have now been designed with controlled number and position of binding sites to decipher the role of multivalency on avidity to a glycosylated surface and on membrane dynamics of glycolipids. A monomeric hexavalent neolectin has been first engineered from a trimeric hexavalent bacterial lectin, From this neolectin template, 13 different neolectins with a valency ranging from 0 to 6 were designed, produced, and analyzed for their ability to bind fucose in solution, to attach to a glycosylated surface and to invaginate glycolipid‐containing giant liposomes. Whereas the avidity only depends on the presence of at least two binding sites, the ability to bend and invaginate membranes critically depends on the distance between two adjacent binding sites.
Selection of DNA‐Encoded Small Molecule Libraries Against Unmodified and Non‐Immobilized Protein Targets
Authors: Zhao Peng , Chen Zitian , Li Yizhou , Sun Dawei , Gao Yuan , Huang Yanyi , Li Xiaoyu 
Published: July 2014

AbstractThe selection of DNA‐encoded libraries against biological targets has become an important discovery method in chemical biology and drug discovery, but the requirement of modified and immobilized targets remains a significant disadvantage. With a terminal protection strategy and ligand‐induced photo‐crosslinking, we show that iterated selections of DNA‐encoded libraries can be realized with unmodified and non‐immobilized protein targets.
Total Synthesis of Gracilamine
Authors: Shi Yingbo , Yang Baochao , Cai Shujun , Gao Shuanhu 
Published: July 2014

AbstractThe total synthesis of gracilamine, a pentacyclic Amaryllidaceae alkaloid, was achieved from simple building blocks. The synthesis features a mild photo‐Nazarov reaction, intramolecular 1,4‐addition, and an intramolecular Mannich reaction. This approach not only confirms the C6 stereochemistry of natural gracilamine, and also provides a novel solution to prepare its derivatives and structurally related natural products.
Practical Aerobic Oxidations of Alcohols and Amines with Homogeneous Copper/TEMPO and Related Catalyst Systems
Authors: Ryland Bradford L. , Stahl Shannon S. 
Published: July 2014

AbstractOxidations of alcohols and amines are common reactions in the synthesis of organic molecules in the laboratory and industry. Aerobic oxidation methods have long been sought for these transformations, but few practical methods exist that offer advantages over traditional oxidation methods. Recently developed homogeneous Cu/TEMPO (TEMPO=2,2,6,6‐tetramethylpiperidinyl‐N‐oxyl) and related catalyst systems appear to fill this void. The reactions exhibit high levels of chemoselectivity and broad functional‐group tolerance, and they often operate efficiently at room temperature with ambient air as the oxidant. These advances, together with their historical context and recent applications, are highlighted in this Minireview.
A Cyclization–Rearrangement Cascade for the Synthesis of Structurally Complex Chiral Gold(I)–Aminocarbene Complexes
Authors: Kolundžić Filip , Murali Annamalai , Pérez‐Galán Patricia , Bauer Jonathan O. , Strohmann Carsten , Kumar Kamal , Waldmann Herbert 
Published: July 2014

AbstractA facile synthesis of chiral cyclic alkyl aminocarbene–gold(I) complexes from gold‐free 1,7‐enyne substrates was developed. The novel cyclization–rearrangement reaction sequence is triggered by the addition of (Me2S)AuCl to different 1,7‐enynes and leads to structurally unique carbene–gold(I) complexes in high yields. These novel complexes are catalytically active and inhibit the proliferation of different human cancer cell lines.
Nanoparticle Growth in Supported Nickel Catalysts during Methanation Reaction—Larger is Better
Authors: Munnik Peter , Velthoen Marjolein E. Z. , de Jongh Petra E. , de Jong Krijn P. , Gommes Cedric J. 
Published: July 2014

AbstractA major cause of supported metal catalyst deactivation is particle growth by Ostwald ripening. Nickel catalysts, used in the methanation reaction, may suffer greatly from this through the formation of [Ni(CO)4]. By analyzing catalysts with various particle sizes and spatial distributions, the interparticle distance was found to have little effect on the stability, because formation and decomposition of nickel carbonyl rather than diffusion was rate limiting. Small particles (3–4 nm) were found to grow very large (20–200 nm), involving local destruction of the support, which was detrimental to the catalyst stability. However, medium sized particles (8 nm) remained confined by the pores of the support displaying enhanced stability, and an activity 3 times higher than initially small particles after 150 h. Physical modeling suggests that the higher [Ni(CO)4] supersaturation in catalysts with smaller particles enabled them to overcome the mechanical resistance of the support. Understanding the interplay of particle size and support properties related to the stability of nanoparticles offers the prospect of novel strategies to develop more stable nanostructured materials, also for applications beyond catalysis.
Rationalization of an Unusual Solvent‐Induced Inversion of Enantiomeric Excess in Organocatalytic Selenylation of Aldehydes
Authors: Burés Jordi , Dingwall Paul , Armstrong Alan , Blackmond Donna G. 
Published: July 2014

AbstractAn unusual solvent‐induced inversion of the sense of enantioselectivity observed in the α‐selenylation of aldehydes catalyzed by a diphenylprolinol silyl ether catalyst is correlated to the presence of intermediates formed subsequent to the highly selective CSe bond‐forming step in the catalytic cycle. This work provides support for a mechanistic concept for enamine catalysis and includes a general role for “downstream intermediates” in selectivity outcomes in organocatalysis.
Synthesis of (±)‐Tetrapetalone A‐Me Aglycon
Authors: Carlsen Peter N. , Mann Tyler J. , Hoveyda Amir H. , Frontier Alison J. 
Published: July 2014

AbstractThe first synthesis of (±)‐tetrapetalone A‐Me aglycon is described. Key bond‐forming reactions include Nazarov cyclization, a ring‐closing metathesis promoted with complete diastereoselectivity by a chiral molybdenum‐based complex, tandem conjugate reduction/intramolecular aldol cyclization, and oxidative dearomatization.
Enantioselective Assembly of a Ruthenium(II) Polypyridyl Complex into a Double Helix
Authors: Van Hecke Kristof , Cardinaels Thomas , Nockemann Peter , Jacobs Jeroen , Vanpraet Louis , Parac‐Vogt Tatjana N. , Van Deun Rik , Binnemans Koen , Van Meervelt Luc 
Published: July 2014

AbstractEvolution can increase the complexity of matter by self‐organization into helical architectures, the best example being the DNA double helix. One common aspect, apparently shared by most of these architectures, is the presence of covalent bonds within the helix backbone. Here, we report the unprecedented crystal structures of a metal complex that self‐organizes into a continuous double helical structure, assembled by non‐covalent building blocks. Built up solely by weak stacking interactions, this alternating tread stairs‐like double helical assembly mimics the DNA double helix structure. Starting from a racemic mixture in aqueous solution, the ruthenium(II) polypyridyl complex forms two polymorphic structures of a left‐handed double helical assembly of only the Λ‐enantiomer. The stacking of the helices is different in both polymorphs: a crossed woodpile structure versus a parallel columnar stacking.
Enzymetically Regulating the Self‐Healing of Protein Hydrogels with High Healing Efficiency
Authors: Gao Yuzhou , Luo Quan , Qiao Shanpeng , Wang Liang , Dong Zeyuan , Xu Jiayun , Liu Junqiu 
Published: July 2014

AbstractEnzyme‐mediated self‐healing of dynamic covalent bond‐driven protein hydrogels was realized by the synergy of two enzymes, glucose oxidase (GOX) and catalase (CAT). The reversible covalent attachment of glutaraldehyde to lysine residues of GOX, CAT, and bovine serum albumin (BSA) led to the formation and functionalization of the self‐healing protein hydrogel system. The enzyme‐mediated protein hydrogels exhibit excellent self‐healing properties with 100 % recovery. The self‐healing process was reversible and effective with an external glucose stimulus at room temperature.
Syntheses, Structures, and Reactivities of Two Chalcogen‐Stabilized Carbones
Authors: Morosaki Tomohito , Suzuki Tsubasa , Wang Wei‐Wei , Nagase Shigeru , Fujii Takayoshi 
Published: July 2014

AbstractElectronic effects on the central carbon atom of carbone, generated by the replacement of the SIV ligand of carbodisulfane (CDS) with other chalcogen ligands (Ph2E, E=S or Se), were investigated. The carbones Ph2E→C←SPh2(NMe) [E=S(1) or Se(2)] were synthesized from the corresponding salts, and their molecular structures and electronic properties were characterized. The carbone 2 is the first carbone containing selenium as the coordinated atom. DFT calculations revealed the electronic structures of 1 and 2, which have two lone pairs of electrons at the carbon center. The trend in HOMO energy levels, estimated by cyclic voltammetry measurements, for the carbones and CDS follows the order of 2>1>CDS. Analysis of a doubly protonated dication and trication complex revealed that the central carbon atom of 2 behaves as a four‐electron donor.
Polymer Nanoparticle Hydrogels with Autonomous Affinity Switching for the Protection of Proteins from Thermal Stress
Authors: Beierle John M. , Yoshimatsu Keiichi , Chou Beverly , Mathews Michael A. A. , Lesel Benjamin K. , Shea Kenneth J. 
Published: July 2014

AbstractWe report a new material design concept for synthetic, thermally responsive poly(N‐isopropylacrylamide)‐based copolymer nanoparticle (NP) hydrogels, which protect proteins from thermal stress. The NP hydrogels bind and protect a target enzyme from irreversible activity loss upon exposure to heat but “autonomously” release the enzyme upon subsequent cooling of the solution. Incorporation of the optimized amount of negatively charged and hydrophobic comonomers to the NP hydrogels was key to achieve these desired functions. As the NP hydrogels do not show a strong affinity for the enzyme at room temperature, they can remain in solution without adversely affecting enzymatic activity or they can be removed by filtration to leave the enzyme in solution. The results demonstrate the promise of this approach for improving the thermal tolerance of proteins.
Light‐Driven Organocatalysis Using Inexpensive, Nontoxic Bi2O3 as the Photocatalyst
Authors: Riente Paola , Matas Adams Alba , Albero Josep , Palomares Emilio , Pericàs Miquel A. 
Published: July 2014

AbstractThe development of enantioselective catalytic processes that make use of sunlight as the energy source and nontoxic, affordable materials as catalysts represents one of the new and rapidly evolving areas in chemical research. The direct asymmetric α‐alkylation of aldehydes with α‐bromocarbonyl compounds can be successfully achieved by combining bismuth‐based materials as low‐band‐gap photocatalysts with the second‐generation MacMillan imidazolidinone as the chiral catalyst and simulated sunlight as a low‐cost and clean energy source. This reaction also proceeded with high efficiency when the reaction vial was exposed to the morning sunlight on a clear September day in Tarragona, Spain.
Numerical simulation of the effects of vaporization on the motion of PIG during pigging process
Authors: Deng Tao , Gong Jing , Zhou Jun , Zhang Yu , Li Haocheng 
Published: July 2014

ABSTRACTDuring the course of pigging after water pressure test, when pressure drops to vapor pressure, localized vaporization always occurs at pipeline terminations or at physical high points in the pipeline. PIG is most effective when it runs at a near constant speed. The appearance of a vapor region may dramatically affect the PIG motion and ultimately contribute to impulse pressures at the end of pigging process. Large pressures may cause the PIG to run at extremely high speed, which is a highly dangerous situation. Further, the pigging efficiency can be compromised. The proposed model for estimating the pig dynamics takes into account vaporization. The basic equations governing the conservation of mass and momentum for the gas and liquid fluids were solved together with the momentum equations for the pig by applying the method of characteristics. Moreover, the new pigging model takes advantage of discrete‐vapor‐cavity model to predict the vaporization and location of vapor region. Numerical simulation results for gas–liquid pipeline pigging process are in good agreement with field data to validate the model developed. The model also contains the capability of PIG tracking and the prediction of impulse pressures, which can help the operator to control the PIG speed before it reaches the end of the pipeline. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Preparation of asymmetric membranes and their applications in the restoration of groundwater contaminated by trichloroethylene via two‐step bioremediation technology
Authors: Song Zhenyu , Yang Wei , Zhang Jinghui , Bi Tao , Li Ye , Yuan Shanshan 
Published: July 2014

ABSTRACTAsymmetric hollow‐fiber membranes were fabricated via a thermally induced phase‐separation process, and the properties of the membrane were investigated. A bubbleless‐aeration membrane module (BAMM) was designed for the purpose of releasing hydrogen or oxygen. Then, the anaerobic reductive dechlorination (ARD) remediation zone and the aerobic oxidative decomposition (AOD) remediation zone were founded based on the BAMM. The effects of the aeration pressure of hydrogen and oxygen on the oxidation reduction potential (ORP) of the liquid phase were investigated. The groundwater contaminated by trichloroethylene (TCE) was used as the restoring object. The effect of the hydrogen aeration on the ARD process and the effect of the oxygen aeration on the AOD process were also investigated. The results show that the ORP–retention time curve in the ARD zone presented an upward opening parabola of growth, whereas the ORP–retention time curve in the AOD zone presented a downward opening parabola of growth. It took 8 days for TCE to decrease from 500 to 52 μg/L in the ARD zone, whereas it took 24 h for cis‐dichloroethylene to decrease from 52 to 35 μg/L in the AOD zone. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41176.
Overexpression of artemisinic aldehyde Δ11 (13) reductase gene–enhanced artemisinin and its relative metabolite biosynthesis in transgenic Artemisia annua L.
Authors: Yuan Yuan , Liu Wanhong , Zhang Qiaozhuo , Xiang Lien , Liu Xiaoqiang , Chen Min , Lin Zhi , Wang Qiang , Liao Zhihua 
Published: July 2014

AbstractArtemisinic aldehyde Δ11 (13) reductase (DBR2) is the checkpoint enzyme catalyzing artemisinic aldehyde to form dihydroartemisinic aldehyde directly involved in artemisinin biosynthetic pathway. In the present study, DBR2 was employed to engineer the biosynthetic pathway of artemisinin in transgenic plants of Artemisia annua L. Seven independent transgenic plants of A. annua with DBR2 overexpression driven by the cauliflower mosaic virus 35S promoter were obtained by Agrobacterium‐mediated genetic transformation and confirmed by genomic PCR. The results of real‐time qPCR analysis showed that the expression levels of DBR2 gene in all the seven transgenic lines were significantly higher than in nontransgenic control. The high‐performance liquid chromatography analysis of artemisinin and its relative metabolites demonstrated that the contents of artemisinin and its direct precursor dihydroartemisinic acid were remarkably increased in the transgenic plants of A. annua with DBR2 overexpression. Interestingly, it was also found that the contents of arteannuin B and its direct precursor artemisinic acid in the branch pathway competing against artemisinin biosynthesis were also improved in DBR2‐overexpressed A. annua plants. The transgenic results in the present study indicated that DBR2 is a useful structural gene in engineering the artemisinin biosynthetic pathway to develop genetically modified A. annua with the higher yield of artemisinin.
Capillary electrophoresis coupled with electrochemiluminescence for determination of atomoxetine hydrochloride and the study on its interactions with three proteins
Authors: Zeng Hua‐jin , Yang Ran , Zhang Ying , Li Jian‐jun , Qu Ling‐bo 
Published: July 2014

ABSTRACTA simple, rapid and sensitive method for the determination of atomoxetine hydrochloride (AH) by capillary electrophoresis with electrochemiluminescence detection (CE‐ECL) using tris(2,2′‐bipyridyl) ruthenium (II) was developed. Under optimized conditions, the determinations of AH in capsules and rat plasmas and the study on its interactions with three plasma proteins, including bovine serum albumin, cytochrome c and myoglobin were performed successfully. Relative to some previous studies, in this paper the methodologies for the determination of AH in aqueous solution and spiked plasma systems were established, respectively. By comparing the difference between the two work curves of two systems, the matrix effect in plasma samples on the determination of AH by the CE‐ECL method was discussed in detail. The results indicated that the effect of the matrix in plasma samples should not be ignored even if no obvious interference was found in the electropherograms and the establishment of method validation in complex samples by the CE‐ECL method was necessary. Copyright © 2014 John Wiley & Sons, Ltd.