bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metal‐Free Aminooxygenation of Alkynes: Efficient Synthesis of 3‐Aroylimidazo[1,2‐a]‐N‐Heterocycles
Authors: Reddy K. Ranjith , Gupta Ajai Prakash , Das Parthasarathi 
Published: April 2016

AbstractAn expeditious, one‐pot, N‐iodosuccinimide‐promoted reaction has been developed for the synthesis of 3‐aroylimidazo[1,2‐a]pyridines from 3‐phenylpropiolaldehyde and 2‐aminopyridines.This aminooxygenation process of alkynes is general and was successfully extended to access 3‐aroylimidazo[1,2‐a]pyrazines and 3‐aroylimidazo[1,2‐b]pyridazines. With the metal‐free conditions and great efficiency in expanding molecule diversity, this method is superior to the existing procedures in the synthesis of 3‐aroylimidazo[1,2‐a]‐N‐heterocycles.
C3 Alkylation of Indoles Catalyzed by Carbocations under Continuous‐Flow Conditions
Authors: Wan Li , Zhu Wentong , Qiao Kai , Sun Xiaoning , Fang Zheng , Guo Kai 
Published: April 2016

AbstractA fast and practical protocol for the C3 alkylation of varied indole substrates catalyzed by carbocations was developed under continuous‐flow conditions. Because of the enhanced mass‐ and heat‐transfer features of the microreactor, the reaction time was significantly reduced compared with batch conditions. The functional group tolerance of this method is good, the substrate scope for indoles and α,β‐unsaturated carbonyls is broad. In addition, the reactants were employed in the ratio of 1:1 to achieve good to excellent yields. It is an effective reaction to cut down chemical waste and is of benefit for environment protection from an industrial production point of view.
Anthranil: An Aminating Reagent Leading to Bifunctionality for Both C(sp3)−H and C(sp2)−H under Rhodium(III) Catalysis
Authors: Yu Songjie , Tang Guodong , Li Yingzi , Zhou Xukai , Lan Yu , Li Xingwei 
Published: April 2016

AbstractPrevious direct C−H nitrogenation suffered from simple amidation/amination with limited atom‐economy and is mostly limited to C(sp2)−H substrates. In this work, anthranil was designed as a novel bifunctional aminating reagent for both C(sp2)−H and C(sp3)−H bonds under rhodium(III) catalysis, thus affording a nucleophilic aniline tethered to an electrophilic carbonyl. A tridendate rhodium(III) complex has been isolated as the resting state of the catalyst, and DFT studies established the intermediacy of a nitrene species.
Engineering Stacks of V‐Shaped Polyaromatic Compounds with Alkyl Chains for Enhanced Emission in the Solid State
Authors: Sekiguchi Shoya , Kondo Kei , Sei Yoshihisa , Akita Munetaka , Yoshizawa Michito 
Published: April 2016

AbstractA V‐shaped bisanthracene derivative with three butyl groups formed two types of emissive solids that display bluish green and blue fluorescence (ΦF=72 and 32 %, respectively), depending on the preparation conditions. The crystal and powder X‐ray analyses reveal that the highly emissive solid adopts a head‐to‐head arrangement with discrete stacks of the anthracene moieties, whereas the moderately emissive solid adopts a head‐to‐tail arrangement without the stacks. The obtained molecular arrangements are transformed by thermal stimuli accompanying the change in fluorescence. Furthermore, large enhancements of dye emissions (12–45‐fold) through highly efficient host–guest energy transfer were achieved in the solid state by adding minute amounts of various fluorescent dyes (e.g. rubrene and Nile red) to the V‐shaped compound.
Effect of thermal annealing on the mechanical and thermal properties of polylactic acid–cellulosic fiber biocomposites
Authors: Pérez‐Fonseca A. A. , Robledo‐Ortíz J. R. , González‐Núñez R. , Rodrigue D. 
Published: April 2016

ABSTRACTPolylactic acid (PLA) biocomposites were produced by a combination of extrusion and injection molding with three cellulosic reinforcements (agave, coir, and pine) and contents (10, 20, and 30%). In particular, some samples were subjected to thermal annealing (105 °C for 1 h) to modify the crystallinity of the materials. In all cases, morphological (scanning electron microscopy) and thermal (differential scanning calorimetry, dynamical mechanical thermal analysis) characterizations were related to the mechanical properties (Charpy impact, tensile and flexural tests). The results showed that annealing increased the crystallinity for all the materials produced, but different mechanical behaviors were observed depending on fiber type and content. For example, annealing increased the impact strength and flexural modulus of PLA and PLA biocomposites (agave, coir, and pine), while decreasing their flexural strength. But the main conclusion is that fiber addition combined with thermal annealing can substantially increase the thermal stability of the studied materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43750.
Hypervalent‐Iodine(III)‐Mediated Oxidative Methodology for the Synthesis of Fused Triazoles
Authors: Kamal Raj , Kumar Vipan , Kumar Ravinder 
Published: April 2016

AbstractThe organic chemistry of hypervalent organoiodine compounds has been an area of unprecedented development. This surge in interest in the use of hypervalent iodine compounds has mainly been owing to their highly selective oxidizing properties, environmentally benign character and commercial availability. Hypervalent iodine reagents have also been used as an alternative to toxic heavy metals, owing to their low toxicity and ease of handling. Hypervalent organoiodine(III) reagents are versatile oxidants that have been successfully employed to extend the scope of selective oxidative transformations of complex organic molecules in synthetic chemistry. This Focus Review concerns the tandem in situ generation and 1,5‐electrocyclization of N‐heteroaryl nitrilimines into fused triazoles. We describe the importance of recently developed hypervalent‐organoiodine(III)‐catalyzed oxidative cyclization reactions, building towards the conclusion that hypervalent iodine chemistry is a promising frontier for oxidative cyclization, in particular of hydrazones, for the synthesis of fused triazoles.
Facile Hydrazine‐Hydrothermal Syntheses and Characterizations of Two Quaternary Thioarsenates(III): Two‐Dimensional SrAg4As2S6⋅2 H2O and One‐Dimensional BaAgAsS3
Authors: Yan Dongming , Liu Chang , Chai Wenxiang , Zheng Xuerong , Zhang Luodong , Zhi Mingjia , Zhou Chunmei , Zhang Qichun , Liu Yi 
Published: April 2016

AbstractTwo new quaternary thioarsenates(III), SrAg4As2S6⋅2 H2O (1) and BaAgAsS3 (2), have been prepared through a hydrazine‐hydrothermal method at low temperature. Compound 1 possesses a two‐dimensional (2D) layer network, while compound 2 features a one‐dimensional (1D) column structure. The detailed structure analysis indicates that Sr2+ and Ba2+ cations have different directing effects on the structures of thioarsenates(III). Both experimental and theoretical studies demonstrate that compounds 1 and 2 are narrow‐gap semiconductors. Our success in synthesizing these two quaternary thioarsenates(III) proves that the hydrazine‐hydrothermal technique is a powerful yet facile synthetic method for exploring new complex chalcogenides with diverse crystal structures and interesting physical properties.
Preparation of Magnetic Tubular Nanoreactors for Highly Efficient Catalysis
Authors: Yang Shuliang , Peng Li , Cao Changyan , Wei Fang , Liu Jian , Zhu Ya‐Nan , Liu Chang , Wang Xiaoshi , Song Weiguo 
Published: April 2016

AbstractWe report an efficient and controllable route to prepare magnetic tubular nanoreactors composed of a mesoporous SiO2 shell with iron‐noble metal nanoparticles inside. The key of this method is to design and fabricate Fe nanoparticles encapsulated in a mesoporous SiO2 shell. Making use of a galvanic replacement reaction between Fe and noble metal ions, all of the noble metal nanoparticles are loaded inside the mesoporous SiO2 shell, and thus nanoreactors are formed. Taking Pd as an example, the prepared Pd−Fe@meso‐SiO2 tubular nanoreactor exhibits a high catalytic activity and excellent reusability for styrene hydrogenation under mild conditions. This study provides a facile route to fabricate magnetic nanoreactors with enhanced catalytic properties.
On the link between cold fronts and hail in Switzerland
Authors: Schemm Sebastian , Nisi Luca , Martinov Andrey , Leuenberger Daniel , Martius Olivia 
Published: April 2016

AbstractHail is the costliest atmospheric hazard in Switzerland, causing substantial damage to agriculture, cars and buildings every year. In this study, a 12‐year statistic of objectively identified cold fronts and a radar‐based hail statistic are combined to investigate the co‐occurrence of cold fronts and hail in Switzerland. In a first step, an automated front identification scheme, which has previously been designed for and applied to global reanalysis data, is modified for a high‐resolution regional analysis data set. This front detection method is then adapted, tested and applied to the Consortium for Small Scale Modelling (COSMO) analysis data for the extended hail season (May to September) in the years 2002–2013. The resulting cold front statistic is presented and discussed. In a second step, the frequency of cold fronts is linked to a high‐resolution radar‐based hail statistic to determine the relative fraction of hail initiation events in pre‐frontal environments. Up to 45% of all detected hail events in north‐eastern and southern Switzerland form in pre‐frontal zones. Similar fractions are identified upstream of the Jura and the Black Forest mountains. The percentage of front‐related hail formation is highest in regions where hail is statistically less frequent, with the exception of southern Switzerland. Furthermore, it is shown that fronts create wind‐sheared environments, which are favourable for hail cells.
Propensities of peptides containing the Asn‐Gly segment to form β‐turn and β‐hairpin structures
Authors: Kang Young Kee , Yoo In Kee 
Published: April 2016

ABSTRACTThe propensities of peptides that contain the Asn‐Gly segment to form β‐turn and β‐hairpin structures were explored using the density functional methods and the implicit solvation model in CH2Cl2 and water. The populations of preferred β‐turn structures varied depending on the sequence and solvent polarity. In solution, β‐hairpin structures with βI′ turn motifs were most preferred for the heptapeptides containing the Asn‐Gly segment regardless of the sequence of the strands. These preferences in solution are consistent with the corresponding X‐ray structures. The sequence, H‐bond strengths, solvent polarity, and conformational flexibility appeared to interact to determine the preferred β‐hairpin structure of each heptapeptide, although the β‐turn segments played a role in promoting the formation of β‐hairpin structures and the β‐hairpin propensity varied. In the heptapeptides containing the Asn‐Gly segment, the β‐hairpin formation was enthalpically favored and entropically disfavored at 25°C in water. The calculated results for β‐turns and β‐hairpins containing the Asn‐Gly segment imply that these structural preferences may be useful for the design of bioactive macrocyclic peptides containing β‐hairpin mimics and the design of binding epitopes for protein–protein and protein–nucleic acid recognitions. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 653–664, 2016.
Prognostic significance of carotid and vertebral ultrasound in ischemic stroke patients
Authors: Muscari Antonio , Bonfiglioli Andrea , Magalotti Donatella , Puddu Giovanni M. , Zorzi Veronica , Zoli Marco 
Published: April 2016

AbstractObjectivesThe ultrasound investigation of carotid and vertebral arteries is routinely performed in stroke patients to determine the etiopathogenetic classification and possible need of revascularization. However, the medium and long‐term prognostic implications of carotid and vertebral ultrasound in ischemic stroke patients are not yet known.MethodsThis study included 309 ischemic stroke patients (mean age 76.3; 160 men). They all had undergone carotid and vertebral ultrasound (carotid stenoses were measured according to the European Carotid Surgery Trial [ECST] method). After a median interval of 9.4 months, a telephone follow‐up was performed to determine their outcome. Dependency or death (modified Rankin scale‐mRS >2) and all cause mortality were the study end‐points.ResultsAt follow‐up, 158 patients had a mRS >2. In multivariate analysis, of 13 variables univariately predictive of dependency or death, only National Institutes of Health Stroke Scale (NIHSS) score (P < 0.0001), age (P < 0.0001) and ipsi‐ or contralateral carotid stenosis ≥60% (O.R. 3.5, 95% C.I. 1.5–8.6, P = 0.006) remained associated with a mRS >2. Sixty‐nine patients had died. In a Cox proportional hazards regression, of 10 variables univariately predictive of mortality, only NIHSS score (P < 0.0001), age (P = 0.003), total anterior circulation syndrome (P = 0.004), vertebral Doppler abnormalities (O.R. 2.2, 95% C.I. 1.3–3.6, P = 0.006), male sex (P = 0.02), and hypercholesterolemia (P = 0.04, inverse relationship) remained associated with mortality.ConclusionsIn stroke patients, carotid stenoses ≥60%, ipsi‐ or contralateral to cerebral lesions, were associated with an increased medium and long‐term probability of dependency or death, and abnormalities of vertebrobasilar flow were a significant indicator of death risk, independent of stroke severity and age.
Enhanced Heat Stability of α‐Chymotrypsin through Single‐Enzyme Confinement in Attoliter Liposomes
Authors: Yoshimoto Makoto , Yamada Jun , Baba Misaki , Walde Peter 
Published: April 2016

AbstractThe entrapment of α‐chymotrypsin (α‐CT) within 70–140 nm liposomes formed from POPC (1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine) leads to an unexpected and remarkable increase in the thermal stability of the enzyme. This finding is based on the observation that heating aqueous suspensions of α‐CT‐containing POPC liposomes to 80 °C for 30 minutes resulted in partial enzyme inactivation, whereas the same treatment of aqueous solutions of free α‐CT inactivated the enzyme completely. The stabilizing effect of enzyme confinement in the attoliter volumes of the liposomes was found to increase with decreasing numbers of α‐CT molecules per liposome. Single‐enzyme confinement was particularly effective, as intermolecular interactions between heat‐denatured α‐CT molecules (causing irreversible inactivation) are not possible.
Nucleoside‐Based Diarylethene Photoswitches: Synthesis and Photochromic Properties
Authors: Wang Hai‐Xia , Xi Dan‐Dan , Xie Ming‐Sheng , Wang Hui‐Xuan , Qu Gui‐Rong , Guo Hai‐Ming 
Published: April 2016

AbstractDiarylethene photoswitches based on the natural nucleoside deoxyadenosine were designed and synthesized. In aqueous solution, some of them exhibited good photochromic properties, including clear changes in color upon irradiation at 365 nm, red‐shifts of the absorption wavelength, with good fatigue resistance, thermal stability, conversion efficiency, and base‐pairing properties.
Study design and rationale of the heterotopic implantation of the Edwards‐Sapien XT transcatheter valve in the inferior VEna cava for the treatment of severe tricuspid regurgitation (HOVER) trial
Authors: O'Neill Brian P. , Wheatley Grayson , Bashir Riyaz , Edmundowicz Daniel , O'Murchu Brian , O'Neill William W. , Patil Pravin , Chen Andrew , Forfia Paul , Cohen Howard A. 
Published: April 2016

BackgroundTricuspid regurgitation (TR) is an under treated disease. Although surgery for TR remains an effective therapy, many patients are considered to be at a high risk or otherwise inoperable. Caval valve implant (CAVI) offers an alternative to surgery in these patients. Trials assessing the safety and efficacy of caval valve implant are lacking. Methods: The Heterotopic Implantation Of the Edwards‐Sapien XT Transcatheter Valve in the Inferior VEna cava for the treatment of severe Tricuspid Regurgitation (HOVER) trial is an FDA approved, physician initiated, prospective, non‐blinded (open label), non‐randomized safety and feasibility study to determine the safety and efficacy of the heterotopic implantation of the Edwards‐Sapien XT valve in the inferior vena cava for the treatment of severe TR in patients who are at high risk or inoperable. Patients with severe TR in the absence of severe pulmonary hypertension will be recruited. They will be evaluated by a multi‐disciplinary team who will agree by consensus that the patients’ symptoms are from TR. They will undergo imaging to assess the size of the inferior vena cava (IVC) to determine feasibility of the procedure. If patients meet the inclusion criteria and are free from exclusion criteria, after informed consent they will be eligible for enrollment in the study. A total of 30 patients will be enrolled. The primary objective of the study will be to demonstrate procedural success at 30‐days and patient success at 1‐year. Conclusion: Caval valve implant may present an alternative for patients who are at high risk or inoperable for tricuspid valve surgery (TVS) for TR. © 2016 Wiley Periodicals, Inc.
A novel maneuver to facilitate retrograde wire externalization during retrograde chronic total occlusion percutaneous coronary intervention
Authors: Carlino Mauro , Azzalini Lorenzo , Colombo Antonio 
Published: April 2016

BackgroundAlthough the retrograde approach has improved the success rate and procedural efficiency of chronic total occlusion (CTO) percutaneous coronary intervention (PCI), it can still be challenging and time‐consuming. We introduce a novel technique that aims to facilitate the critical step of retrograde wire externalization during reverse controlled antegrade and retrograde tracking and dissection (CART), which we named DRAFT (Deflate, Retract and Advance into the Fenestration Technique).Materials and MethodsDRAFT is performed by simultaneous retraction of the deflating antegrade balloon (after inflation in the subintimal space) and advancement of the retrograde looped wire in the same plane through the transient fenestrations created by reverse CART, in order to cross through the fenestrated dissection flap before its collapse. The retrograde wire is then quickly and easily advanced into the antegrade guiding catheter.ResultsDRAFT was used in 11 patients (8 with right coronary artery and 3 with left anterior descending artery CTOs). Several different guidewires were used, since this technique does not need any specific wire to be performed. DRAFT was successful in all cases, after at most five attempts. CTO PCI was then completed as per standard retrograde practice. No complications occurred.ConclusionsDRAFT is a versatile approach that allows easy and quick re‐entry of the retrograde wire into the true lumen during reverse CART. It can be performed with a variety of guidewires and is feasible both in the left and right coronary arteries. © 2016 Wiley Periodicals, Inc.
TriGuard™ HDH embolic deflection device for cerebral protection during transcatheter aortic valve replacement
Authors: Samim Mariam , van der Worp Bart , Agostoni Pierfrancesco , Hendrikse Jeroen , Budde Ricardo P.J. , Nijhoff Freek , Ramjankhan Faiz , Doevendans Pieter A. , Stella Pieter R. 
Published: April 2016

ObjectivesThis study aims to evaluate the safety and performance of the new embolic deflection device TriGuard™HDH in patients undergoing TAVR.BackgroundTranscatheter aortic valve replacement (TAVR) is associated with a high incidence of new cerebral ischemic lesions. The use of an embolic protection device may reduce the frequency of TAVR‐related embolic events.MethodsThis prospective, single arm feasibility pilot study included 14 patients with severe symptomatic aortic stenosis scheduled for TAVR. Cerebral diffusion weighted magnetic resonance imaging (DWI) was planned in all patients one day before and at day 4 (±2) after the procedure. Major adverse cerebral and cardiac events (MACCEs) were recorded for all patients. Primary endpoints of this study were I) device performance success defined as coverage of the aortic arch takeoffs throughout the entire TAVR procedure and II) MACCE occurrence. Secondary endpoints included the number and the volume of new cerebral ischemic lesions on DWI.ResultsThirteen patients underwent transfemoral TAVR and one patient a transapical procedure. Edwards SAPIEN valve prosthesis was implanted in 8 (57%) patients and Medtronic CoreValve prosthesis in the remaining 6 (43%). Predefined performance success of the TriGuard™HDH device was achieved in 9 (64%) patients. The composite endpoint MACCE occurred in none of the patients. Post‐procedural DWI was performed in 11 patients. Comparing the DWI of these patients to a historical control group showed no reduction in number [median 5.5 vs. 5.0, P = 0.857], however there was a significant reduction in mean lesion volume per patient [median 13.8 vs. 25.1, P = 0.049].ConclusionThis study showed the feasibility and safety of using the TriGuard™HDH for cerebral protection during TAVR. This device did not decrease the number of post‐procedural new cerebral DWI lesions, however its use showed decreased lesion volume as compared to unprotected TAVR. © 2016 Wiley Periodicals, Inc.
Three‐Dimensional Coral‐Like Structure Constructed of Carbon‐Coated Interconnected Monocrystalline SnO2 Nanoparticles with Improved Lithium‐Storage Properties
Authors: Xu Wangwang , Cui Xiaodan , Xie Zhiqiang , Dietrich Grant , Wang Ying 
Published: April 2016

AbstractThe applications of alloying/dealloying materials as anode for LIB electrode are hindered by its dramatic volume variations and sluggish kinetics. Herein, to overcome these challenges, we report a facile and scalable approach fabricating coral‐like SnO2/C composite electrodes through a top‐down strategy followed by a sol–gel carbon‐coating method. During the synthesis, well‐defined SnS2 nanoflowers and dopamine serve as structural template and carbon source for integrating the desired structure. The three‐dimensional coral‐like SnO2/C composite exhibits a high reversible capacity of 648 mAh g−1 after 50 electrochemical cycles and a low capacity fading of 0.778 % per cycle from the 2nd to the 50th cycle, demonstrating an outstanding cycling stability. It also shows a discharge capacity of 1294, 784, 658, 532, and 434 mAh g−1 at a specific current of 100, 200, 500, 1000 and 2000 mAh g−1, respectively, and retains a specific capacity of 719 mAh g−1 when the specific current goes back to 100 mA g−1, displaying an excellent rate capability. Compared to SnS2 nanoflowers and bare interconnected SnO2 nanoparticles anode, the optimized coral‐like SnO2/C composite shows significantly improved electrochemical performances in terms of rate capability and cycling reversibility, demonstrating great potential as superior anodes in next‐generation lithium ion batteries.