bluuebunny/crossref_metadata_2025_split huggingface dataset:
Small‐molecule G‐quadruplex interactions: Systematic exploration of conformational space using multiple molecular dynamics
Authors: Husby Jarmila , Todd Alan K. , Platts James A. , Neidle Stephen 
Published: July 2013

ABSTRACTG‐quadruplexes are higher‐order four‐stranded structures formed from repetitive guanine‐containing tracts in nucleic acids. They comprise a core of stacked guanine‐quartets linked by loops of length and sequence that vary with the context in which the quadruplex sequence occurs. Such sequences can be found in a number of genomic environments; at the telomeric ends of eukaryotic chromosomes, in promoter regions, in untranslated sequences and in open reading frames. Quadruplex formation can inhibit telomere maintenance, transcription and translation, especially when enhanced by quadruplex‐binding small molecules, and quadruplex targeting is currently of considerable interest. The available experimental structural data shows that quadruplexes can have high conformational flexibility, especially in loop regions, which has hampered attempts to use high‐throughput docking to find quadruplex‐binding small‐molecules with new scaffolds or to optimize existing ones with structure‐based design methods. An approach to overcome the challenge of quadruplex conformational flexibility is presented here, which uses a combined multiple molecular dynamics and sampling approach. Two test small molecules have been used, RHPS4 and pyridostatin, which themselves have contrasting degrees of conformational flexibility. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 989–1005, 2013.
Influence of amylopectin structure and degree of phosphorylation on the molecular composition of potato starch lintners
Authors: Wikman Jeanette , Blennow Andreas , Buléon Alain , Putaux Jean‐Luc , Pérez Serge , Seetharaman Koushik , Bertoft Eric 
Published: July 2013

ABSTRACTMorphology, molecular structure, and thermal properties of potato starch granules with low to high phosphate content were studied as an effect of mild acid hydrolysis (lintnerization) to 80% solubilization at two temperatures (25 and 45°C). Light microscopy showed that the lintners contained apparently intact granules, which disintegrated into fragments upon dehydration. Transmission electron microscopy of rehydrated lintners revealed lacy networks of smaller subunits. The molecular composition of the lintners suggested that they largely consisted of remnants of crystalline lamellae. When lintnerization was performed at 45°C, the lintners contained more of branched dextrins compared to 25°C in both low and intermediate phosphate‐containing samples. High‐phosphate‐containing starch was, however, unaffected by temperature and this was probably due to an altered amylopectin structure rather than the phosphate content. After lintnerization, the melting endotherms were broad with decreased onset and increased peak melting temperatures. The relative crystallinity was lower in lintners prepared at 45°C. A hypothesis that combines the kinetics of lintnerization with the molecular and thermal characteristics of the lintners is presented. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 257–271, 2014.
Molecularly imprinted polymer in microextraction by packed sorbent for the simultaneous determination of local anesthetics: lidocaine, ropivacaine, mepivacaine and bupivacaine in plasma and urine samples
Authors: Daryanavard Seyed Mosayeb , Jeppsson‐Dadoun Amin , Andersson Lars I. , Hashemi Mahdi , Colmsjö Anders , Abdel‐Rehim Mohamed 
Published: July 2013

ABSTRACTThis study presents the use of molecularly imprinted polymer (MIP) as packing material for microextraction by packed syringe (MEPS) to achieve higher extraction selectivity. Pentycaine was used as template for MIP. Development and validation of the determination of lidocaine, ropivacaine, mepivacaine and bupivacaine in human plasma and urine samples utilizing MIP‐MEPS and liquid chromatography–tandem mass spectrometry (LC‐MS/MS) were carried out. The MEPS MIP‐cartridge could be used for 100 extractions before it was discarded. The extraction recovery ranged from 60 to 80%. The correlation coefficients values were >0.999 for all assays using lidocaine, ropivacaine, mepivacaine and bupivacaine in the calibration range 5–2000 nmol/L. The accuracy of the studied compounds, given as a percentage variation from the nominal concentration values, ranged from ‐4.9 to 8.4% using plasma and urine samples. The between‐batch precision, given as the relative standard deviation, at three different concentrations (quality control samples) was ranged from −4.7 to 14.0% and from 1.8 to 12.7% in plasma and urine, respectively. The lower limit of quantification and limit of detection of the studied substances were 5.0 and 1.0 nm, respectively. Copyright © 2013 John Wiley & Sons, Ltd.
Determination of chikusetsusaponin V and chikusetsusaponin IV in rat plasma by liquid chromatography–mass spectrometry and its application to a preliminary pharmacokinetic study
Authors: Qi Dongli , Yang Xiaolin , Chen Jing , Li Fei , Shi Xiupu , Zhang Chunfeng , Yang Zhonglin 
Published: July 2013

ABSTRACTA sensitive liquid chromatography–electrospray ionization–mass spectrometry method has been developed and validated for determination of two major bioactive saponins in rat plasma after oral administration of saponins extracted from Rhizoma Panacis Japonici, including chikusetsusaponin V and chikusetsusaponin IV for the first time. Akebia saponin D was used as the internal standard (IS). Plasma samples were prepared by protein precipitation with methanol. A Phenomenex C18 column (150 × 4.6 mm, 4 µm) was used as the analytical column with a mobile phase of acetonitrile and 0.05% aqueous formic acid. Mass spectrometric detection was achieved by single quadrupole mass spectrometer equipped with an electrospray ionization interface operating in negative ionization mode. Calibration curves showed good linearity over the concentration range of 5–500 ng/mL for the two analytes in rat plasma. The lower limit of quantification was 5 ng/mL. The intra‐ and inter‐batch precisions were within 10.3% and accuracy ranged from −3.9 to 5.4%. The method was validated and successfully applied to the preliminary pharmacokinetic study of chikusetsusaponin V and chikusetsusaponin IV in rat plasma after oral administration of saponins extracted from Rhizoma Panacis Japonici. Copyright © 2013 John Wiley & Sons, Ltd.
Ductal spasm during performance of transcatheter ductal occlusion
Authors: Batlivala Sarosh P. , Glatz Andrew C. , Gillespie Matthew J. , Dori Yoav , Rome Jonathan J. 
Published: July 2013

ObjectivesTranscatheter patent ductus arteriosus (PDA) occlusion is a staple of pediatric catheterization laboratories. We present the phenomenon of significant PDA spasm to prevent failure to occlude a hemodynamically significant duct.BackgroundTranscatheter techniques have evolved, allowing safe and effective occlusion of PDAs in younger and smaller patients. Neonatal care is evolving with increasing survival at younger gestational ages. Premature infants often have PDAs, so the proportion of formerly premature children referred for transcatheter ductal occlusion will likely rise.MethodsWe reviewed all transcatheter PDA occlusions performed at our institution since 2001 (N = 331). Retrospective data included: gestational age, age at catheterization, precatheterization echocardiographic parameters, PDA size (after spasm relief), device specifications, and most recent follow‐up data.ResultsSeven cases were identified. Median age was 12 months, median gestational age was 28 weeks. All were born prematurely. All PDAs were restrictive and six had left‐heart volume overload. All patients were examined by the interventional cardiologist and had ductal murmurs. When reauscultated (three of seven), murmurs were absent during spasm. Once spasm relieved, PDA diameters ranged from 1.5 to 8 (median 2) mm. All patients accommodated a 6‐mm—or larger—Amplatzer device. No significant complications occurred and all patients were well at follow‐up.ConclusionsDuctal spasm occurs during transcatheter occlusion and may be an unrecognized cause of procedural failure. The phenomenon seems to occur in children born prematurely, and can occur after infancy. Loss of a continuous murmur confirms the diagnosis. Care should be taken to avoid device under‐sizing when spasm occurs. © 2013 Wiley Periodicals, Inc.
Delayed perforation after percutaneous coronary intervention: Rare and potentially lethal
Authors: Stathopoulos Ioannis A. , Kossidas Konstantinos , Garratt Kirk N. 
Published: July 2013

IntroductionCardiac tamponade is a grave but fortunately uncommon complication of percutaneous coronary intervention (PCI). Few studies have specifically addressed angiographic characteristics and outcomes associated with delayed cardiac tamponade after PCI. With the current study we tried to define the incidence of this complication and to characterize the events in order to improve our understanding of the likely mechanisms.Methods/ResultsWe reviewed 23,399 PCIs performed at our institution during an 8‐year period (1999–2006) and we present 10 cases of delayed tamponade. A brief description of each case is provided and findings from retrospective review of the coronary angiography, as well as features of PCI complexity are presented. Also, we summarize the procedural characteristics and outcomes. Delayed perforations are rare and possibly preventable. They usually occur after complex interventions and mostly attributed to distal wire perforations. Surgical intervention is needed less often today than before. Successful pericardiocentesis is of paramount importance.ConclusionsThe potential lethal outcome associated with delayed tamponade emphasizes the importance of taking steps to prevent this complication. First, prevention and, second, prompt treatment should be the goal, with the use of appropriate technique, clinical awareness, and vigilance. © 2013 Wiley Periodicals, Inc.
A meta‐analysis of transcatheter closure of patent foramen ovale versus medical therapy for prevention of recurrent thromboembolic events in patients with cryptogenic cerebrovascular events
Authors: Pineda Andrés M. , Nascimento Francisco O. , Yang Solomon C. , Kirtane Ajay J. , Sommer Robert J. , Beohar Nirat 
Published: July 2013

ObjectivesWe sought to perform a meta‐analysis of randomized controlled trials (RCTs) comparing percutaneous patent‐foramen‐ovale (PFO) closure with medical therapy for preventing recurrent thromboembolic events after cryptogenic stroke.BackgroundObservational studies suggested that transcatheter PFO closure decreases recurrent events after cryptogenic stroke; however, three recent RCTs failed to demonstrate such benefit.MethodsTrials were identified from the PubMed and Cochrane databases. Primary endpoint was the composite of transient ischemic attack (TIA) and ischemic cerebrovascular events (CVA). Both intention‐to‐treat (ITT) and as‐treated analyses (AT) were performed.ResultsThree RCTs met inclusion criteria. The pooled data provided 2,303 patients, of which 1,150 were in the PFO closure group and 1,153 in the medical therapy group. In the ITT analysis, there were 43 events (3.7%) of the composite end point in the closure group compared with 61 events (5.3%) in the medical therapy group, with a trend in favor of the PFO closure (OR = 0.70; 95% CI, 0.47–1.05, P = 0.08). The incidences of TIA, ischemic CVA, and bleeding were not statistically different between the groups. There was a trend for the more frequent occurrence of atrial fibrillation in the PFO closure group (OR = 3.29; 95% CI, 0.86–12.60, P = 0.08). In the AT analysis, the composite end point was significantly less frequent in the PFO closure group (OR = 0.62; 95% CI, 0.41–0.94, P = 0.02).ConclusionsIn this meta‐analysis of contemporary RCTs, successful transcatheter closure of PFO might be more effective than medical therapy alone for the prevention of recurrent thromboembolic events. © 2013 Wiley Periodicals, Inc.
Safety and feasibility of transulnar catheterization when ipsilateral radial access is not available
Authors: Kedev Sasko , Zafirovska Biljana , Dharma Surya , Petkoska Danica 
Published: July 2013

ObjectivesWe evaluated the safety and feasibility of transulnar approach when ipsilateral radial access was not available.Methods and ResultsFrom March 2011 until February 2013, 476 consecutive patients who underwent transulnar catheterization were included in a single center prospective registry of effectiveness and safety. Diagnostic coronary angiography accounted for 42% of cases, percutaneous coronary intervention (PCI) for 38%, and 17% underwent carotid artery stenting. A subgroup analysis was done in 240 patients with documented ipsilateral radial artery occlusion (RAO). Procedural success was 97% with a crossover rate of 3% to transfemoral access. Hand ischemia was not observed in any patient on day 1 after procedure and on 1 month follow‐up. None of the patients showed ulnar nerve injury. Two patients developed major forearm hematoma that resolved without clinical consequences. Minor access site hematoma occurred in 8%. Severe clinical spasm occurred in two patients. Asymptomatic ulnar artery occlusion at 1 month follow‐up was detected in 3.1%. There was no difference between patients with or without RAO in terms of procedural success and any vascular complication.ConclusionTransulnar approach is safe and feasible alternative wrist access when performed by experienced radial operators, providing high success rate and low incidence of vascular complications. © 2013 Wiley Periodicals, Inc.
From Homogeneous to Heterogeneous Catalysis of the Three‐Component Coupling of Oxysulfonyl Azides, Alkynes, and Amines
Authors: Yang Tao , Cui Hao , Zhang Changhe , Zhang Li , Su Cheng‐Yong 
Published: July 2013

AbstractA reliable procedure for the synthesis of oxysulfonyl azides has been developed and applied to the three‐component coupling reactions of azides, alkynes, and amines catalyzed homogeneously by CuI, which led to the formation of N‐oxysulfonyl amidines with good yields. To fully evaluate the catalytic activity towards this coupling reaction, two coordination frameworks, namely, Cu2I2(PDIN) without micropores and Cu2I2(BTTP4) with micropores (PDIN=1,4‐phenylene diisonicotinate, BTTP4=benzene‐1,3,5‐triyltriisonicotinate), were prepared by a facile one‐pot reaction as heterogeneous catalysts. Catalytic results showed that nonporous Cu2I2(PDIN) was almost inactive for the three‐component coupling reaction, whereas microporous Cu2I2(BTTP4) was an efficient heterogeneous catalyst for the synthesis of N‐oxysulfonyl amidines. Furthermore, porous Cu2I2(BTTP4) displayed a shape‐selective performance with respect to the alkyne substrates, and aromatic alkynes were preferable to aliphatic alkynes. The location of the catalytically active sites in the Cu2I2(BTTP4) framework has been studied by a series physical techniques, which includes powder XRD, CO2 gas adsorption, IR spectroscopy, energy dispersive X‐ray analysis, and X‐ray photoelectron spectroscopy, which suggests that the catalytic sites are not only on the external surface but also inside the micropores.
Enantioselective Merger of Aminocatalysis with π‐Lewis Acid Metal Catalysis: Asymmetric Preparation of Carbo‐ and Heterocycles
Authors: Praveen Chandrasekaran , Montaignac Benjamin , Vitale Maxime R. , Ratovelomanana‐Vidal Virginie , Michelet Véronique 
Published: July 2013

AbstractThe metallo‐organocatalyzed enantioselective synthesis of various five‐membered carbo‐ and heterocyclic structures through the merger of aminocatalysis with the catalytic indium(III) or copper(I) activation of α‐disubstituted formyl alkynes is described. The use of indium trichloride associated with the (R)‐1,1′‐bis‐(2‐naphthylamine) ligand led to encouraging results with up to 85:15 enantiomeric ratio. After a careful examination of several other strategies, the best synergic catalytic system, which combines a chiral copper(I) complex with cyclohexylamine, afforded the enantioselective preparations of cyclopentane, indane, and pyrrolidine scaffolds with moderate to excellent control of the all‐carbon quaternary stereogenic centers created through such cyclization processes.
Modification of Disposable Red‐Mud Catalysts for Slurry‐Phase Hydrocracking of Vacuum Residue
Authors: Nguyen‐Huy C. , Kim H. , Kweon H. , Kim D. K. , Kim D.‐W. , Oh S. H. , Shin E. W. 
Published: July 2013

AbstractA disposable iron‐based catalyst, red mud, was modified by different dissolution‐precipitation methods. The catalysts obtained were characterized by nitrogen adsorption, X‐ray diffraction, scanning electron microscopy, and ammonia temperature‐programmed desorption. They were tested for slurry‐phase hydrocracking of vacuum residue in a batch reactor. The red‐mud catalyst activated by phosphoric acid showed the highest catalytic activity since the activation by phosphoric acid resulted in the decrease in particle size which facilitated the transformation of red mud to the active sulfide form in the reaction.
Investigation of Nucleation Kinetics by Nephelometric Measurements
Authors: Parisi M. , Chianese A. 
Published: July 2013

AbstractThe application of a nephelometric probe for investigation of nucleation kinetics is reported. First a check of direct proportionality of the signal with respect to the surface of the solid suspension was performed, followed by an experimental analysis of the nucleation of potassium sulfate crystals from aqueous solutions by applying both polythermal and isothermal methods. The adopted instrument allowed to accurately detect the metastable zone width and the induction time and to monitor the first period of time after nucleation. These latter measurements give an indication of the overall crystal mass evolution at the starting of the crystallization operation.
Synthesis of 5,6‐Diarylpyridin‐2(1H)‐ones from Isoflavones
Authors: Zhu Mulin , Zhang Zunting , Xue Dong , Qiao Jinfeng , Liang Yong , Wnuk Stanislaw F. 
Published: July 2013

AbstractA simple method for the cyclocondensation of substituted isoflavones with cyanoacetamide in the presence of sodium hydroxide to give an array of 3‐cyano‐5,6‐diarylpyridin‐2(1H)‐ones in good yields is reported.
Selective Reduction of Nitroarenes with Molybdenum Disulfide
Authors: Huang Lei , Luo Pingfei , Xiong Man , Chen Rizhi , Wang Yong , Xing Weihong , Huang Jun 
Published: July 2013

AbstractCommercial MoS2 was found to be a highly selective catalyst for the reduction of nitrobenzenes to the corresponding anilines with hydrazine under mild conditions. MoS2 is not only much cheaper, but also more selective than noble metal catalysts for the reduction of functional nitrobenzenes to the corresponding anilines. Nitrobenzenes with halides (F, Cl, Br and I) were reduced selectively, and the corresponding anilines were obtained in excellent yields, and no dehalogenation was detected. Functional groups such as NH2, OH, alkene groups were tolerated during the reduction of the nitro compounds. The reduction of p‐chloronitrobenzene was studied over MoS2 and Pd/C respectively with hydrazine. The yield of p‐chloroaniline was much higher with MoS2 than that with Pd/C at full conversion.
Nickel‐Catalyzed ortho‐Selective Hydrodefluorination of N‐Containing Heterocycle‐Polyfluoroarenes
Authors: He Yi , Chen Zhao , He Chun‐Yang , Zhang Xingang 
Published: July 2013

AbstractAn effective and facile method for preparation of partially fluorinated aromatics via Nickel catalyzed, chelation‐assisted ortho selective hydrodefluorination of polyfluoroarnes with triethylsilane has been developed, in which N‐containing heterocycles were used as directing groups. The advantage of this protocol is its simple catalytic system with use of inexpensive and readily available NiCl2·6H2O as a catalyst.
Array languages and the N‐body problem
Authors: Cockshott P. , Gdura Y. , Keir P. 
Published: July 2013

SUMMARYThis paper is a description of the contributions to the Scottish Informatics and Computer Science Alliance Multi‐core Challenge on many body planetary simulation made by a compiler group at the University of Glasgow. Our group is part of the Computer Vision and Graphics research group, and we have for some years been developing array compilers because we think these are a good tool both for expressing graphics algorithms and for exploiting the parallelism that computer vision applications require. We shall describe experiments using two languages on two different platforms, and we shall compare the performance of these with reference C implementations running on the same platforms. Finally, we shall draw conclusions both about the viability of the array language approach as compared with other approaches used in the challenge and also about the strengths and weaknesses of the two, very different, processor architectures we used. Copyright © 2013 John Wiley & Sons, Ltd.
Iron Azides with Cyclam‐Derived Ligands: Are They Precursors for High‐Valent Iron Nitrides in the Gas Phase?
Authors: Krahe Oliver , Neese Frank , Engeser Marianne 
Published: July 2013

AbstractThe FeIII azide complexes [FeIII(N3)cyclam‐ac]PF6 (1⋅PF6), [FeIII(N3)Me3cyclam‐ac]PF6 (2⋅PF6), and trans‐[FeIII(N3)2cyclam]ClO4 (3⋅ClO4) (cyclam=1,4,8,11‐tetraazacyclotetradecane; cyclam‐ac=1,4,8,11‐tetraazacyclotetradecane‐1‐acetate; Me3cyclam‐ac=4,8,11‐trimethyl‐1,4,8,11‐tetraazacyclotetra‐decane‐1‐acetate) are studied in the gas phase with special emphasis on the formation of high‐valent iron nitrides by collision‐induced dissociation. Whereas the azide complex with unsubstituted cyclam‐acetate 1 as major fragmentation expels N2 to form a high‐valent FeV nitride complex, a similar process is not observed for its methyl‐substituted congener. In contrast, loss of an azide radical results in iron reduction to FeII. Thus, the gas‐phase behavior is parallel to the results obtained in spectroscopic studies of photolyzed frozen solution. The diazide complex 3 mainly fragments via consecutive losses of HN3 without change in the iron oxidation state. However, small amounts of dinitrogen loss and thus FeV nitride formation are also observed. While it is assumed that the FeV nitride complex detected by Mössbauer spectroscopy in frozen solution is still coordinated by an azide in the trans position to the nitride, both the complex [FeV(N)(N3)(cyclam)]+still bearing an intact second azide and the coordinatively unsaturated [FeV(N)(cyclam‐H)]+ are observed in the gas phase.