bluuebunny/crossref_metadata_2025_split huggingface dataset:
What is normal nasal airflow? A computational study of 22 healthy adults
Authors: Zhao Kai , Jiang Jianbo 
Published: March 2014

BackgroundNasal airflow is essential for the functioning of the human nose. Given individual variation in nasal anatomy, there is yet no consensus what constitutes normal nasal airflow patterns. We attempt to obtain such information that is essential to differentiate disease‐related conditions.MethodsComputational fluid dynamics (CFD) simulated nasal airflow in 22 healthy subjects during resting breathing. Streamline patterns, airflow distributions, velocity profiles, pressure, wall stress, turbulence, and vortical flow characteristics under quasi–steady state were analyzed. Patency ratings, acoustically measured minimum cross‐sectional area (MCA), and rhinomanometric nasal resistance (NR) were examined for potential correlations with morphological and airflow‐related variables.ResultsCommon features across subjects included: >50% total pressure drop reached near the inferior turbinate head; wall shear stress, NR, turbulence energy, and vorticity were lower in the turbinate than in the nasal valve region. However, location of the major flow path and coronal velocity distributions varied greatly across individuals. Surprisingly, on average, more flow passed through the middle than the inferior meatus and correlated with better patency ratings (r = −0.65, p < 0.01). This middle flow percentage combined with peak postvestibule nasal heat loss and MCA accounted for >70% of the variance in subjective patency ratings and predicted patency categories with 86% success. Nasal index correlated with forming of the anterior dorsal vortex. Expected for resting breathing, the functional impact for local and total turbulence, vorticity, and helicity was limited. As validation, rhinomanometric NR significantly correlated with CFD simulations (r = 0.53, p < 0.01).ConclusionSignificant variations of nasal airflow found among healthy subjects; Key features may have clinically relevant applications.
Crista galli mucocele: endoscopic marsupialization via frontoethmoid approach
Authors: Cervantes Sergio Santino , Lal Devyani 
Published: March 2014

BackgroundWe report the first report of an expansile crista galli (CG) mucocele treated surgically by an endoscopic endonasal approach. Only 1 other case of a CG mucocele has been previously reported in the literature. This was treated by a craniotomy approach.Case ReportWe describe the technique employed in endoscopic marsupialization. We also discuss relevant CG anatomy, pneumatization patterns, surgical approaches, and its potential to cause disease, including CG sinusitis and mucocele formation.ConclusionWe present this case to highlight that the growing experience with endoscopic techniques offer us less morbid and more functional alternatives to a variety of lesions that were once tackled by neurosurgical or external approaches. In the contemporary era, the indications for open approaches and craniotomy for frontal sinus and CG lesions is likely limited. We recommend these patients undergo careful evaluation by a surgeon experienced in advanced endoscopic techniques before being advised to undergo open or craniotomy techniques.
Coaxing Solid‐State Phosphorescence from Tellurophenes
Authors: He Gang , Torres Delgado William , Schatz Devon J. , Merten Christian , Mohammadpour Arash , Mayr Lorenz , Ferguson Michael J. , McDonald Robert , Brown Alex , Shankar Karthik , Rivard Eric 
Published: March 2014

AbstractThe synthesis of the first examples of tellurophenes exhibiting phosphorescence in the solid state and under ambient conditions (room temperature and in air) is reported. Each of these main‐group‐element‐based emitters feature pinacolboronates (BPin) as ring‐appended side groups. The nature of the luminescence observed was also investigated using computational methods.
Point Decoration of Silicon Nanowires: An Approach Toward Single‐Molecule Electrical Detection
Authors: Wang Jindong , Shen Fangxia , Wang Zhenxing , He Gen , Qin Jinwen , Cheng Nongyi , Yao Maosheng , Li Lidong , Guo Xuefeng 
Published: March 2014

AbstractProbing interactions of biological systems at the molecular level is of great importance to fundamental biology, diagnosis, and drug discovery. A rational bioassay design of lithographically integrating individual point scattering sites into electrical circuits is capable of realizing real‐time, label‐free biodetection of influenza H1N1 viruses with single‐molecule sensitivity and high selectivity by using silicon nanowires as local reporters in combination with microfluidics. This nanocircuit‐based architecture is complementary to more conventional optical techniques, but has the advantages of no bleaching problems and no fluorescent labeling. These advantages offer a promising platform for exploring dynamics of stochastic processes in biological systems and gaining information from genomics to proteomics to improve accurate molecular and even point‐of‐care clinical diagnosis.
Silver(I)‐Catalyzed Hydroazidation of Ethynyl Carbinols: Synthesis of 2‐Azidoallyl Alcohols
Authors: Liu Zhenhua , Liu Jianquan , Zhang Lin , Liao Peiqiu , Song Jinna , Bi Xihe 
Published: March 2014

AbstractThe hydroazidation of alkynes is the most straightforward pathway to synthetically useful vinyl azides. However, a general hydroazidation of alkynes remains elusive. Herein, a chemo‐ and regioselective transformation of ethynyl carbinols into vinyl azides is described. This reaction produces a wide variety of 2‐azidoallyl alcohols with high efficiency and in good to excellent yields. These compounds constitute a new class of densely functionalized synthetic intermediates. Their synthetic potential has been demonstrated by further transformations into NH aziridines. The mechanistic aspects of the reaction will attract the attention of chemists working on alkyne chemistry and silver catalysis. The findings that are described in this paper represent significant advances in the regioselective hydroelementation of alkynes and open a new reaction manifold for exploitation.
Total Chemical Synthesis of the Enzyme Sortase AΔN59 with Full Catalytic Activity
Authors: Deng Fang‐Kun , Zhang Liang , Wang Ya‐Ting , Schneewind Olaf , Kent Stephen B. H. 
Published: March 2014

AbstractThe enzyme sortase A is a ligase which catalyzes transpeptidation reactions.1, 2 Surface proteins, including virulence factors, that have a C terminal recognition sequence are attached to Gly5 on the peptidoglycan of bacterial cell walls by sortase A.1 The enzyme is an important anti‐virulence and anti‐infective drug target for resistant strains of Gram‐positive bacteria.2 In addition, because sortase A enables the splicing of polypeptide chains, the transpeptidation reaction catalyzed by sortase A is a potentially valuable tool for protein science.3 Here we describe the total chemical synthesis of enzymatically active sortase A. The target 148 residue polypeptide chain of sortase AΔN59 was synthesized by the convergent chemical ligation of four unprotected synthetic peptide segments. The folded protein molecule was isolated by size‐exclusion chromatography and had full enzymatic activity in a transpeptidation assay. Total synthesis of sortase A will enable more sophisticated engineering of this important enzyme molecule.
Catalytic Transfer Hydrogenation by a Trivalent Phosphorus Compound: Phosphorus‐Ligand Cooperation Pathway or PIII/PV Redox Pathway?
Authors: Zeng Guixiang , Maeda Satoshi , Taketsugu Tetsuya , Sakaki Shigeyoshi 
Published: March 2014

AbstractMain‐group‐element catalysts are a desirable alternative to transition‐metal catalysts because of natural abundance and cost. However, the examples are very limited. Catalytic cycles involving a redox process and E‐ligand cooperation (E=main‐group element), which are often found in catalytic cycles of transition‐metal catalysts, have not been reported. Herein theoretical investigations of a catalytic hydrogenation of azobenzene with ammonia–borane using a trivalent phosphorus compound, which was experimentally proposed to occur through PIII/PV redox processes via an unusual pentavalent dihydridophosphorane, were performed. DFT and ONIOM(CCSD(T):MP2) calculations disclosed that this catalytic reaction occurs through a P‐O cooperation mechanism, which resembles the metal‐ligand cooperation mechanism of transition‐metal catalysts.
Catalytic Asymmetric Synthesis of [2,3]‐Fused Indoline Heterocycles through Inverse‐Electron‐Demand Aza‐Diels–Alder Reaction of Indoles with Azoalkenes
Authors: Tong Min‐Chao , Chen Xuan , Li Jun , Huang Rong , Tao Haiyan , Wang Chun‐Jiang 
Published: March 2014

AbstractAn unprecedented catalytic asymmetric inverse‐electron‐demand aza‐Diels–Alder reaction of indoles with in situ formed azoalkenes is reported. A diverse set of [2,3]‐fused indoline heterocycles were achieved in generally good yields (up to 97 %) with high regioselectivity and diastereoselectivity (>20:1 d.r.), and with excellent enantioselectivity (up to 99 % ee).
Bidirektionale Chemische Kommunikation zwischen nanomechanischen Schaltern
Authors: Pramanik Susnata , De Soumen , Schmittel Michael 
Published: March 2014

AbstractDas Zusammenspiel zwischen biologischen Systemen hängt entscheidend von der Bidirektionalität des chemischen Informationsaustauschs ab. Die Implementierung eines derartigen Kommunikationsprotokolls für abiologische Systeme gelingt unter Nutzung von zwei Nanoschaltern, die beide unter Übertragung von Kupferionen in den Oxidationsstufen +I und +II jeweils als Empfänger und Sender eingesetzt werden können. Selbst bei mikromolaren Konzentrationen verläuft die Kommunikation in beide Richtungen mit t1/2=2–3 min beachtlich schnell. Die Metallionenübertragung löst einen Schwenk des Dreharms um 20 Å an beiden Schaltern und damit beachtliche geometrische und elektronische Veränderungen aus.
Rate Coefficients of C1 and C2 Criegee Intermediate Reactions with Formic and Acetic Acid Near the Collision Limit: Direct Kinetics Measurements and Atmospheric Implications
Authors: Welz Oliver , Eskola Arkke J. , Sheps Leonid , Rotavera Brandon , Savee John D. , Scheer Adam M. , Osborn David L. , Lowe Douglas , Murray Booth A. , Xiao Ping , Anwar H. Khan M. , Percival Carl J. , Shallcross Dudley E. , Taatjes Craig A. 
Published: March 2014

AbstractRate coefficients are directly determined for the reactions of the Criegee intermediates (CI) CH2OO and CH3CHOO with the two simplest carboxylic acids, formic acid (HCOOH) and acetic acid (CH3COOH), employing two complementary techniques: multiplexed photoionization mass spectrometry and cavity‐enhanced broadband ultraviolet absorption spectroscopy. The measured rate coefficients are in excess of 1×10−10 cm3 s−1, several orders of magnitude larger than those suggested from many previous alkene ozonolysis experiments and assumed in atmospheric modeling studies. These results suggest that the reaction with carboxylic acids is a substantially more important loss process for CIs than is presently assumed. Implementing these rate coefficients in global atmospheric models shows that reactions between CI and organic acids make a substantial contribution to removal of these acids in terrestrial equatorial areas and in other regions where high CI concentrations occur such as high northern latitudes, and implies that sources of acids in these areas are larger than previously recognized.
Metal‐Free Photochemical Aromatic Perfluoroalkylation of α‐Cyano Arylacetates
Authors: Nappi Manuel , Bergonzini Giulia , Melchiorre Paolo 
Published: March 2014

AbstractWe report here an operationally simple protocol for the direct aromatic perfluoroalkylation and trifluoromethylation of α‐cyano arylacetates. This metal‐free approach, which occurs at ambient temperature and under visible‐light irradiation, is driven by the photochemical activity of electron donor–acceptor (EDA) complexes, formed in situ by the interaction of transiently generated enolates and perfluoroalkyl iodides. Preliminary mechanistic studies are reported.
Gas‐Phase Synthesis of the Benzyl Radical (C6H5CH2)
Authors: Dangi Beni B. , Parker Dorian S. N. , Yang Tao , Kaiser Ralf I. , Mebel Alexander M. 
Published: March 2014

AbstractDicarbon (C2), the simplest bare carbon molecule, is ubiquitous in the interstellar medium and in combustion flames. A gas‐phase synthesis is presented of the benzyl radical (C6H5CH2) by the crossed molecular beam reaction of dicarbon, C2(X1Σg+, a3Πu), with 2‐methyl‐1,3‐butadiene (isoprene; C5H8; X1A′) accessing the triplet and singlet C7H8 potential energy surfaces (PESs) under single collision conditions. The experimental data combined with ab initio and statistical calculations reveal the underlying reaction mechanism and chemical dynamics. On the singlet and triplet surfaces, the reactions involve indirect scattering dynamics and are initiated by the barrierless addition of dicarbon to the carbon–carbon double bond of the 2‐methyl‐1,3‐butadiene molecule. These initial addition complexes rearrange via multiple isomerization steps, leading eventually to the formation of C7H7 radical species through atomic hydrogen elimination. The benzyl radical (C6H5CH2), the thermodynamically most stable C7H7 isomer, is determined as the major product.
Balancing the Rate of Cluster Growth and Etching for Gram‐Scale Synthesis of Thiolate‐Protected Au25 Nanoclusters with Atomic Precision
Authors: Yuan Xun , Zhang Bin , Luo Zhentao , Yao Qiaofeng , Leong David Tai , Yan Ning , Xie Jianping 
Published: March 2014

AbstractWe report a NaOH‐mediated NaBH4 reduction method for the synthesis of mono‐, bi‐, and tri‐thiolate‐protected Au25 nanoclusters (NCs) with precise control of both the Au core and thiolate ligand surface. The key strategy is to use NaOH to tune the formation kinetics of Au NCs, i.e., reduce the reduction ability of NaBH4 and accelerate the etching ability of free thiolate ligands, leading to a well‐balanced reversible reaction for rapid formation of thermodynamically favorable Au25 NCs. This protocol is facile, rapid (≤3 h), versatile (applicable for various thiolate ligands), and highly scalable (>1 g Au NCs). In addition, bi‐ and tri‐thiolate‐protected Au25 NCs with adjustable ratios of hetero‐thiolate ligands were easily obtained. Such ligand precision in molecular ratios, spatial distribution and uniformity resulted in richly diverse surface landscapes on the Au NCs consisting of multiple functional groups such as carboxyl, amine, and hydroxy. Analysis based on NMR spectroscopy revealed that the hetero‐ligands on the NCs are well distributed with no ligand segregation. The unprecedented synthesis of multi‐thiolate‐protected Au25 NCs may further promote the practical applications of functional metal NCs.
Real‐Time In Vivo Quantitative Monitoring of Drug Release by Dual‐Mode Magnetic Resonance and Upconverted Luminescence Imaging
Authors: Liu Jianan , Bu Jiwen , Bu Wenbo , Zhang Shengjian , Pan Limin , Fan Wenpei , Chen Feng , Zhou Liangpin , Peng Weijun , Zhao Kuaile , Du Jiulin , Shi Jianlin 
Published: March 2014

AbstractInsufficient or excess drug doses, due to unknown actual drug concentrations at the focus, are one of the main causes of chemotherapy failure for cancers. In this regard, the real‐time monitoring of the release of anticancer drugs from nanoparticle drug delivery systems is of crucial importance, but it remains a critical and unsolved challenge. Herein, we report the proposal and development of a novel concept of real‐time monitoring of NIR‐triggered drug release in vitro and in vivo by using simultaneous upconverted luminescence (UCL) and magnetic resonance (MR) imaging. Such a monitoring strategy features the high sensitivity of UCL and the high‐resolution, noninvasiveness, and tissue‐depth‐independence of MR imaging. The dual‐mode real‐time and quantitative monitoring of drug release can be applied to determine online the drug concentrations in vivo in the tissue regions of interest and, therefore, to avoid insufficient or excess drug dosings.
In Vivo Chemoembolization and Magnetic Resonance Imaging of Liver Tumors by Using Iron Oxide Nanoshell/Doxorubicin/Poly(vinyl alcohol) Hybrid Composites
Authors: Wang Yi‐Xiang J. , Zhu Xiao‐Ming , Liang Qi , Cheng Christopher H. K. , Wang Wei , Leung Ken Cham‐Fai 
Published: March 2014

AbstractA hybrid composite made up of superparamagnetic iron oxide nanoshells encapsulating the anticancer drug doxorubicin and bound together by poly(vinyl alcohol) was developed. Transcatheter arterial delivery in an in vivo liver tumor model led to embolization of the liver tumor blood vessels. Embolization was followed by disassembly of the composite. The nanoshells were then able to pass through the leaky tumor vasculature into the tumor tissue, thereby leading to slow and sustained release of the drug. As well as being relatively noncytotoxic, the composite was responsive to magnetic resonance imaging, thus making it a potentially useful theranostic agent.
Synthesis of Cyano‐Substituted Diaryltetracenes from Tetraaryl[3]cumulenes
Authors: Gawel Przemyslaw , Dengiz Cagatay , Finke Aaron D. , Trapp Nils , Boudon Corinne , Gisselbrecht Jean‐Paul , Diederich François 
Published: March 2014

AbstractA versatile, two‐step synthesis of highly substituted, cyano‐functionalized diaryltetracenes has been developed, starting from easily accessible tetraaryl[3]cumulenes. This unprecedented transformation is initiated by [2+2] cycloaddition of tetracyanoethylene (TCNE) to the proacetylenic central double bond of the cumulenes to give an intermediate zwitterion, which after an electrocyclization cascade and dehydrogenation yields 5,5,11,11‐tetracyano‐5,11‐dihydrotetracenes in a one‐pot procedure. A subsequent copper‐assisted decyanation/aromatization provided the target 5,11‐dicyano‐6,12‐diaryltetracene derivatives. All of the postulated structures were confirmed by X‐ray crystallography. The new chromophores are thermally highly stable and feature promising fluorescence properties for potential use in optoelectronic devices. They are selective chemosensors for CuI ions, which coordinate to one of the CN substituents and form a 1:1 complex with an association constant of Ka=1.5×105 L mol−1 at 298 K.
Comparison of amine solutions performance for gas sweetening
Authors: Abkhiz Vahid , Heydari Isa 
Published: March 2014

ABSTRACTUsing different kinds of amines, in Fajr‐e‐Jam gas refinery, including mixed or activated amines, have provided the chance for better analysis of different kinds of amines performance. In the current work, the most important parameters in gas sweetening refineries such as amine circulation rate, steam consumption, CO2 and mercaptan removal were investigated for sweetening trains utilizing diethanolamine (DEA), methyldiethanolamine (MDEA), DEA/MDEA and activated methyldiethanolamine (aMDEA). In the case of steam consumption and circulation rates, MDEA and aMDEA, show the less required rates to meet lean amine loadings. For CO2 removal aMDEA has the best efficiency. In the case of mercaptan removal, DEA shows the best absorption rate compared with other three amines. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Effect of acrylonitrile–butadiene–styrene on flow behavior and mechanical properties of polylactic acid/low density polyethylene blend
Authors: Hamad Kotiba , Ko Young Gun , Kaseem Mosab , Deri Fawaz 
Published: March 2014

ABSTRACTThe influence of acrylonitrile–butadiene–styrene (ABS) copolymer content on the properties of polylactic acid (PLA)/low density polyethylene (LDPE) blend (50/50) was investigated in the present paper. The blend (PLA/LDPE/ABS) was prepared in different ratios using a laboratory scale single screw extruder. The prepared blends were characterized in terms of rheological and mechanical properties. Rheological properties were studied using a capillary rheometer, and the Bagley's correction was performed. Shear rate (γr), shear stress (τr), shear viscosity (ηr), and non‐Newtonian index (n) were determined. The relationship between shear viscosity and temperature was also studied, and the flow activation energy at a constant shear rate (Eγ) was determined. The mechanical properties of the blends were investigated on dog‐bone‐shaped samples obtained by an injection molding machine. The tensile tests were performed using Testometric M350‐10KN, and the stress at break, strain at break, and Young's modulus were determined. Rheological properties revealed that the blend exhibited shear‐thinning behavior over the range of the studied shear rates, and the viscosity of the blend increased as the ABS content increased, whereas the flow activation energy decreased. Based on the mechanical properties determined for the prepared blends, it was found that no relation between ABS content and stress at break of the blend was regarded, whereas Young's modulus was significantly improved by the addition of ABS. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Dry and wet mechanical properties of polylactic acid in the presence of canola oil
Authors: Kumar Rakesh , Josse Camille , Anandjiwala Rajesh 
Published: March 2014

ABSTRACTPolylactic acid (PLA) is a compostable and biodegradable polymer obtained from renewable resources. They can be used in the packaging and medical industries. For our study, two grades of PLA resins were procured. One grade was procured from Cereplast, Inc., USA, (CPL) and other from NatureWorks LLC, USA, (NWPL). Mechanical, thermal, thermomechanical and morphological studies were carried out for PLA resins procured from both the sources. Virgin and modified canola oil (0.25–0.5% with respect to PLA) were mixed manually with CPL and NWPL to prepare injection‐moulded specimens. Mechanical, thermal, thermomechanical and morphological studies of injection moulded PLA samples in the presence of canola oil were then carried out. Results indicated that canola oil acted as a plasticizer for PLA specimens. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Ultrafast Dynamics of Solvation and Charge Transfer in a DNA‐Based Biomaterial
Authors: Choudhury Susobhan , Batabyal Subrata , Mondol Tanumoy , Sao Dilip , Lemmens Peter , Pal Samir Kumar 
Published: March 2014

AbstractCharge migration along DNA molecules is a key factor for DNA‐based devices in optoelectronics and biotechnology. The association of a significant amount of water molecules in DNA‐based materials for the intactness of the DNA structure and their dynamic role in the charge‐transfer (CT) dynamics is less documented in contemporary literature. In the present study, we have used a genomic DNA–cetyltrimethyl ammonium chloride (CTMA) complex, a technological important biomaterial, and Hoechest 33258 (H258), a well‐known DNA minor groove binder, as fluorogenic probe for the dynamic solvation studies. The CT dynamics of CdSe/ZnS quantum dots (QDs; 5.2 nm) embedded in the as‐prepared and swollen biomaterial have also been studied and correlated with that of the timescale of solvation. We have extended our studies on the temperature‐dependent CT dynamics of QDs in a nanoenvironment of an anionic, sodium bis(2‐ethylhexyl)sulfosuccinate reverse micelle (AOT RMs), whereby the number of water molecules and their dynamics can be tuned in a controlled manner. A direct correlation of the dynamics of solvation and that of the CT in the nanoenvironments clearly suggests that the hydration barrier within the Arrhenius framework essentially dictates the charge‐transfer dynamics.