bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of polyhedral oligomeric silsesquioxane to the stabilization and performance enhancement of poly(4‐methyl‐2‐pentyne) nanocomposite membranes for natural gas conditioning
Authors: Khosravi Arash , Vatani Ali , Mohammadi Toraj 
Published: April 2017

ABSTRACTThe application of octatrimethylsiloxy polyhedral oligomeric silsesquioxane (POSS) nanoparticles was investigated in the fabrication of novel reverse‐selective poly(4‐methyl‐2‐pentyne) (PMP) nanocomposite membranes for the separation of heavier hydrocarbons from methane. Generally, PMP and PMP–fumed silica (FS) nanocomposite membranes suffer severe physical aging with approximately 40% permeation flux reduction over 120 days. A straightforward strategy was introduced to suppress the physical aging of PMP and also to improve the thermal stability without compromising the selectivities and permeabilities through the incorporation of a functionalized POSS–FS binary filler system. Fourier transform infrared spectroscopy and scanning electron microscopy proved productive interactions between the fillers and polymer, with a fair compatibility between them. Thermogravimetric analysis confirmed that the thermal stability of the neat PMP was enhanced by the incorporation of the fillers into the nanocomposites. The addition of POSS and FS led to improved operational performance, such as in the permeability and selectivity, over the neat PMP. The permeation stabilities of the PMP–POSS and PMP–FS–POSS nanocomposite membranes were clearly improved over a long time (120 days). The permeation data indicated that the PMP–3 wt % POSS–20 wt % FS nanocomposite membrane is promising for C3H8/N2 and C3H8/CH4 separation. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45158.
Enantioselective Organocatalytic Synthesis of a Secoyohimbane‐Inspired Compound Collection with Neuritogenic Activity
Authors: Förster Tim , López‐Tosco Sara , Ziegler Slava , Antonchick Andrey P. , Waldmann Herbert 
Published: April 2017

AbstractNatural products provide evolutionary validated core structures to inspire the synthesis of new compound collections endowed with neurite growth‐promoting activity. Rhynchophylline is the major component of Uncaria species, and has been used to treat neurological diseases in Chinese traditional medicine. Based on the structure of this spirocyclic secoyohimbane alkaloid, we developed a highly enantioselective and efficient organocatalyzed synthesis method to provide a tetracyclic secoyohimbane scaffold incorporating a quaternary and three tertiary stereogenic centers, in a one‐pot multistep reaction sequence. A compound collection of derived secoyohimbanes was synthesized and expanded by decorating the periphery of the basic scaffold with additional substituents to increase the diversity. Evaluation of the different subcollections of secoyohimbanes for modulation of neurite outgrowth in the SH‐SY5Y human cell line led to the discovery of new compounds that promote neurite outgrowth.
Sequence‐Specific Covalent Capture Coupled with High‐Contrast Nanopore Detection of a Disease‐Derived Nucleic Acid Sequence
Authors: Nejad Maryam Imani , Shi Ruicheng , Zhang Xinyue , Gu Li‐Qun , Gates Kent S. 
Published: April 2017

AbstractHybridization‐based methods for the detection of nucleic acid sequences are important in research and medicine. Short probes provide sequence specificity, but do not always provide a durable signal. Sequence‐specific covalent crosslink formation can anchor probes to target DNA and might also provide an additional layer of target selectivity. Here, we developed a new crosslinking reaction for the covalent capture of specific nucleic acid sequences. This process involved reaction of an abasic (Ap) site in a probe strand with an adenine residue in the target strand and was used for the detection of a disease‐relevant T→A mutation at position 1799 of the human BRAF kinase gene sequence. Ap‐containing probes were easily prepared and displayed excellent specificity for the mutant sequence under isothermal assay conditions. It was further shown that nanopore technology provides a high contrast—in essence, digital—signal that enables sensitive, single‐molecule sensing of the cross‐linked duplexes.
Polymer‐Supported Palladium(II) Carbene Complexes: Catalytic Activity, Recyclability, and Selectivity in C−H Acetoxylation of Arenes
Authors: Majeed Maitham H. , Shayesteh Payam , Wallenberg L. Reine , Persson Axel R. , Johansson Niclas , Ye Lei , Schnadt Joachim , Wendt Ola F. 
Published: April 2017

AbstractHeterogeneous catalysts for selective oxidation of C−H bonds were synthesized by co‐polymerization of new N‐heterocyclic carbene‐palladium(II) (NHC‐PdII) monomers with divinylbenzene. The polymer‐supported NHC‐PdII‐catalysed undirected C−H acetoxylation of simple and methylated arenes as well as polyarenes, with similar or superior efficiency compared to their homogeneous analogues. In particular, the regioselectivity has been improved in the acetoxylation of biphenyl and naphthalene compared to the best homogeneous catalysts. The new polymer‐supported catalysts maintain the original oxidation state of PdII after repeated catalytic reactions, and exhibit no significant leaching of palladium. In addition, the new catalysts have been successfully recovered and reused without loss of activity over several cycles of reactions.
Enantioselective synthesis of (S)‐naproxen using immobilized lipase on chitosan beads
Authors: Gilani Saeedeh L. , Najafpour Ghasem D. , Heydarzadeh Hamid D. , Moghadamnia Aliakbar 
Published: April 2017

AbstractS‐naproxen by enantioselective hydrolysis of racemic naproxen methyl ester was produced using immobilized lipase. The lipase enzyme was immobilized on chitosan beads, activated chitosan beads by glutaraldehyde, and Amberlite XAD7. In order to find an appropriate support for the hydrolysis reaction of racemic naproxen methyl ester, the conversion and enantioselectivity for all carriers were compared. In addition, effects of the volumetric ratio of two phases in different organic solvents, addition of cosolvent and surfactant, optimum pH and temperature, reusability, and inhibitory effect of methanol were investigated. The optimum volumetric ratio of two phases was defined as 3:2 of aqueous phase to organic phase. Various water miscible and water immiscible solvents were examined. Finally, isooctane was chosen as an organic solvent, while 2‐ethoxyethanol was added as a cosolvent in the organic phase of the reaction mixture. The optimum reaction conditions were determined to be 35 °C, pH 7, and 24 h. Addition of Tween‐80 in the organic phase increased the accessibility of immobilized enzyme to the reactant. The optimum organic phase compositions using a volumetric ratio of 2‐ethoxyethanol, isooctane and Tween‐80 were 3:7 and 0.1% (v/v/v), respectively. The best conversion and enantioselectivity of immobilized enzyme using chitosan beads activated by glutaraldehyde were 0.45 and 185, respectively.
Synthesis, Characterization and Electrochemical Properties of 4,5‐Diazafluoren‐9‐yl or Fluoren‐9‐yl Terminated Homobimetallic Ruthenium and Osmium Allenylidene, Alkynyl‐Allenylidene Complexes
Authors: Huang Jinbo , Zhou Xiaoxi , Zhao Qianyi , Li Shunhua , Xia Haiping 
Published: April 2017

AbstractA variety of rigid ruthenium and osmium allenylidene [M1Cl(PΛP)2 = C = C(4,5‐diazafluoren‐9‐yl){M2(CHC(PPh3)CHC(PPh3)Cl2(PPh3)2}][PF6]3 (4a: M1=Os, M2=Os, PΛP=dppm; 4b: M1=Os, M2=Ru, PΛP=dppm; 4c: M1=Ru, M2=Os, PΛP=dppe; 4d: M1=Ru, M2=Ru, PΛP=dppe), ruthenium alkynyl‐allenylidene complexes trans‐[(dppe)2Ru(C≡CPh)Ru = C = C(R)][PF6] (6a: R = fluoren‐9‐yl; 6b: R = 4,5‐diazafluoren‐9‐yl), trans‐{(dppe)2[=C = C(fluoren‐9‐yl)]Ru(C ≡ C‐R‐C ≡ C)Ru[(=C = C(fluoren‐9‐yl)(dppe)2]} [PF6]2 (8a, R = 1,4‐phenylene; 8b, R = 1,3‐phenylene) terminated by 4,5‐diazafluoren‐9‐yl and fluoren‐9‐yl group have been prepared. These allenylidene complexes were derived from 9‐ethynyl‐9‐fluorenol and 9‐hydroxy‐9‐ethynyl‐4,5‐diazafluorene in the presence of cis‐OsCl2(dppm)2 and cis‐RuCl2(dppe)2. The respective products have been fully characterized by 1H, 13C, 31P NMR spectrometry, IR spectrometry, elemental analysis, and UV/Vis spectrophotometry. Moreover, electrochemical studies reveal that the dinuclear complexes display a quasi‐reversible redox behavior and a moderate electronic communication between the two metal centers in 8a. UV–vis studies show a remarkable absorption in the region (λmax = 300‐700 nm) for these complexes.
Synovial sarcoma metastatic to the parotid gland: A possible pitfall in salivary gland fine needle aspiration cytology. Report of a case with immunocytochemical and fluorescence in situ hybridization findings
Authors: Fulciniti Franco , Barizzi Jessica , Martin Vittoria , Tarallo Vittorio , Ermanni Stefano 
Published: April 2017

AbstractWe report one case of metastatic synovial sarcoma (SS) to the parotid gland in a 93‐year‐old male. The patient had undergone upper left pulmonary lobectomy with mediastinal lymphadenectomy for SS of the lung 5 years before. The cytopathologic presentation and the immunocytochemical findings on the FNA sample were suggestive of a spindle cell myoepithelioma, while a SYT rearrangement was identified by a FISH performed on a cytological smear of the lesion. The diagnosis was further confirmed also by positive immunocytochemical expression of TLE1 on a section from the obtained cell block. The cytologic and immunophenotypic findings are shortly discussed in view of the reported immunophenotypic inconsistency of SS and of its differential diagnosis with spindle cell myoepithelioma of the salivary glands.The importance of the recently described TLE1 staining and its close correlation to SYT rearrangement is briefly discussed.
Endometrial cells on Pap tests: ideal reporting is more complex than just finding the right age
Authors: Fischer Gabor , Haddad Maha , Cormier Karen 
Published: April 2017

AbstractBackgroundThe age for reporting normal endometrial cells (EMCs) on Pap tests was changed to ≥ 45 years in the latest Bethesda update (2014). This recommendation is solely based on age with no consensus on optimal reporting guidelines.MethodsPap tests with EMCs for women ≥40 years were retrieved from our Laboratory Information System (LIS). Patient age, last menstrual period (LMP) and available follow‐up histology were recorded. Follow‐up diagnoses were categorized as: no significant pathology, benign, hyperplasia ± atypia, or malignant. The Fisher's exact test was used to assess the association between categorical variables, p < .05 (two‐sided test) was considered significant.ResultsOf the 352 cases with EMCs, 155 had surgical follow‐up. They showed no malignancy in the 89 women between 40‐49 years, compared with five malignancies in the 66 women 50+ years (p = .016). The number of cases with significant pathology (hyperplasia and malignant) was 4 (40‐49 years) vs. 11 (50+ years) (p = 0.029). The LMP was inconsistently provided (57%) and women identified as postmenopausal on requisition comprised all the malignancies and half the hyperplasias.ConclusionCombined effort by pathologists and clinicians necessitates determining the best standardized clinicopathologic guidelines to report EMCs and appropriate follow‐up. Increasing the required age to ≥50 years would provide more optimal patient management; however, there are other considerations beyond age. Reporting EMCs in postmenopausal women is a reasonable alternative requiring consistent and accurate recording of LMP. Improving provided information for pathologists, determining reporting requirements for EMCs and standardizing clinical follow‐up should be a multidisciplinary effort. Diagn. Cytopathol. 2017;45:587–591. © 2017 Wiley Periodicals, Inc.
A structural approach for understanding multispecies coexistence
Authors: Saavedra Serguei , Rohr Rudolf P. , Bascompte Jordi , Godoy Oscar , Kraft Nathan J. B. , Levine Jonathan M. 
Published: April 2017

AbstractAlthough observations of species‐rich communities have long served as a primary motivation for research on the coexistence of competitors, the majority of our empirical and theoretical understanding comes from two‐species systems. How much of the coexistence observed in species‐rich communities results from indirect effects among competitors that only emerge in diverse systems remains poorly understood. Resolving this issue requires simple, scalable, and intuitive metrics for quantifying the conditions for coexistence in multispecies systems, and how these conditions differ from those expected based solely on pairwise interactions. To achieve these aims, we develop a structural approach for studying the set of parameter values compatible withn‐species coexistence given the geometric constraints imposed by the matrix of competition coefficients. We derive novel mathematical metrics analogous to stabilizing niche differences and fitness differences that measure the range of conditions compatible with multispecies coexistence, incorporating the effects of indirect interactions emerging in diverse systems. We show how our measures can be used to quantify the extent to which the conditions for coexistence in multispecies systems differ from those that allow pairwise coexistence, and apply the method to a field system of annual plants. We conclude by presenting new challenges and empirical opportunities emerging from our structural metrics of multispecies coexistence.
Low Carbon Governance in Multi‐level Structures: EU–India relations on energy and climate
Authors: Jörgensen Kirsten , Wagner Christian 
Published: April 2017

AbstractSince 2000, the European Union (EU), a leader in global climate politics, has been looking for alternative avenues to enforce climate relations with other countries. Employing a multi‐level governance lens, this article focuses on the EU–India bilateral relations on energy and climate. The analysis finds strong opportunities for mutually beneficial cooperation on low carbon development, a potential that has not yet been realized. The stimulating and accelerating impact that multi‐level reinforcement could have in the energy and climate relations between the EU and India has not been exploited by either side yet. The various forms of cooperation that include the national government and the states in India offer more room for linkages which might move the Indian/European climate cooperation ahead further. Copyright © 2017 John Wiley & Sons, Ltd and ERP Environment
Highly Sensitive Choline Oxidase Enzyme Inhibition Biosensor for Lead Ions Based on Multiwalled Carbon Nanotube Modified Glassy Carbon Electrodes
Authors: Magar Hend Samy , Ghica Mariana Emilia , Abbas Mohammed Nooredeen , Brett Christopher M. A. 
Published: April 2017

AbstractThe determination of lead ions by inhibition of choline oxidase enzyme has been evaluated for the first time using an amperometric choline biosensor. Choline oxidase (ChOx) was immobilized on a glassy carbon electrode (GCE) modified with multiwalled carbon nanotubes (MWCNT) through cross‐linking with glutaraldehyde. In the presence of ChOx, choline was enzymatically oxidized into betaine at –0.3 V versus Ag/AgCl reference electrode, lead ion inhibition of enzyme activity causing a decrease in the choline oxidation current. The experimental conditions were optimised regarding applied potential, buffer pH, enzyme and substrate concentration and incubation time. Under the best conditions for measurement of the lowest concentrations of lead ions, the ChOx/MWCNT/GCE gave a linear response from 0.1 to 1.0 nM Pb2+ and a detection limit of 0.04 nM. The inhibition of ChOx by lead ions was also studied by electrochemical impedance spectroscopy, but had a narrower linear response range and low sensitivity. The inhibition biosensor exhibited high selectivity towards lead ions and was successfully applied to their determination in tap water samples.
Exploring Online Learning Data Using Fractal Dimensions
Authors: Guo Hongwen 
Published: April 2017

AbstractData collected from online learning and tutoring systems for individual students showed strong autocorrelation or dependence because of content connection, knowledge‐based dependency, or persistence of learning behavior. When the response data show little dependence or negative autocorrelations for individual students, it is suspected that students are randomly guessing the answers or that they are inconsistent in learning behavior. In addition, the global and local rates of correct responses may reflect students' proficiency in the learning process. This study shows that the dependence of online data may be characterized by the fractal dimension as a summary statistic locally and globally. The rate of correct responses and the global and local fractal dimensions of individual students' responses may indicate their learning behavior in short and long learning windows. The results may shed light on when individual students are experiencing difficulties in the learning process.
Numerical simulation of agricultural sediment and pesticide runoff: RZWQM and PRZM comparison
Authors: Chen Huajin , Zhang Xuyang , Demars Christopher , Zhang Minghua 
Published: April 2017

AbstractAgricultural sediment and pesticide runoff is a widespread ecological and human health concern. Numerical simulation models, such as Root Zone Water Quality Model (RZWQM) and Pesticide Root Zone Model (PRZM), have been increasingly used to quantify off‐site agricultural pollutant movement. However, RZWQM has been criticized for its inability to simulate sedimentation processes. The recent incorporation of the sedimentation module of Groundwater Loading Effects of Agricultural Management Systems has enabled RZWQM to simulate sediment and sediment‐associated pesticides. This study compares the sediment and pesticide transport simulation performance of the newly released RZWQM and PRZM using runoff data from 2 alfalfa fields in Davis, California. A composite metric (based on coefficient of determination, Nash–Sutcliffe efficiency, index of agreement, and percent bias) was developed and employed to ensure robust, comprehensive assessment of model performance. Results showed that surface water runoff was predicted reasonably well (absolute percent bias <31%) by RZWQM and PRZM after adjusting important hydrologic parameters. Even after calibration, underestimation bias (−89% ≤ PBIAS ≤ −36%) for sediment yield was observed in both models. This might be attributed to PRZM's incorrect distribution of input water and uncertainty in RZWQM's runoff erosivity coefficient. Moreover, the underestimation of sediment might be less if the origin of measured sediment was considered. Chlorpyrifos losses were simulated with reasonable accuracy especially for Field A (absolute PBIAS ≤ 22%), whereas diuron losses were underestimated to a great extent (−98% ≤ PBIAS ≤ −65%) in both models. This could be attributed to the underprediction of herbicide concentration in the top soil due to the limitations of the instantaneous equilibrium sorption model as well as the high runoff potential of herbicide formulated as water‐dispersible granules. RZWQM and PRZM partitioned pesticides into the water and sediment phases similarly. According to model predictions, the majority of pesticide loads were carried via the water phase. On the basis of this study, both RZWQM and PRZM performed well in predicting runoff that carried highly adsorptive pesticides on an event basis, although the more physically based RZWQM is recommended when field‐measured soil hydraulic properties are available.
Use of blood pool agents with steady‐state MRI to assess the vascular system
Authors: Thakor Avnesh S. , Chung John , Patel Premal , Chan Anthony , Ahmed Amdad , McNeil Graeme , Liu David M. , Forster Bruce , Klass Darren 
Published: April 2017

Over the past two decades there have been significant advances in the use of magnetic resonance imaging (MRI) to assess the vascular system. New imaging sequences and improvements in magnet design have enabled the creation of higher spatial resolution images. MRI is now a viable alternative imaging modality when compared to both invasive angiography and computed tomographic angiography. The use of blood pool agents has further facilitated the use of MR angiography (MRA); their high molecular weight allows for lower doses of contrast medium administration while their prolonged presence in the blood stream allows for repeated high‐quality volumetric imaging of both the arterial and venous circulation. As such, MRA is now no longer constrained by the tight windows for first‐pass arterial and venous enhancement, which has resulted in the ability to assess and diagnose a large range of vascular pathologies in both arterial and venous systems. The intent of this review is to highlight MRI findings in common vascular pathologies including peripheral arterial disease (PAD), abnormalities of the abdominal aortic branches, postendovascular aortic aneurysm repair (EVAR) endoleak assessment, popliteal artery entrapment syndrome (PAES), deep venous thrombosis (DVT), vascular thoracic outlet syndrome (TOS), and vascular malformations. In addition, the latest MRI techniques currently used to optimally assess each of these pathologies will be discussed.Level of Evidence: 5Technical Efficacy: Stage 3J. MAGN. RESON. IMAGING 2017;45:1559–1572
Vinylic Rotaxane Cross‐Linker Comprising Different Axle Length for the Characterization of Rotaxane Cross‐linked Polymers
Authors: Sawada Jun , Aoki Daisuke , Takata Toshikazu 
Published: April 2017

SummaryThe [2]rotaxane cross‐linkers (RCs) comprising vinyl group‐terminated axle component having different axle lengths and vinyl group‐containing crown ether were synthesized, and applied to prepare the corresponding rotaxane cross‐linked polymers (RCPs). The preparations of RCP were performed by the radical polymerizations of n‐butyl acrylate in the presence of 0.5 mol% of RCs. Properties of the RCPs were evaluated by swelling ratio, clearly demonstrating that axle length of RC affects swelling ratio of RCPs.
Polymer Networks From Nanosized Functional Precursors
Authors: Dušek Karel , Dušková‐Smrčková Miroslava 
Published: April 2017

SummaryThe majority of cross‐linked systems of practical importance are manufactured from pre‐prepared precursors which are characterized by distributions in the type and number of functional groups and molecular weights. For understanding of the effects of these distributions on network formation and properties and designing new systems, a theoretical insight is necessary that takes these distributions into account. The article lists some examples where the theoretical insight has helped optimize the cross‐linking process and application properties.