bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chiral Metal–Organic Frameworks Bearing Free Carboxylic Acids for Organocatalyst Encapsulation
Authors: Liu Yan , Xi Xiaobing , Ye Chengcheng , Gong Tengfei , Yang Zhiwei , Cui Yong 
Published: November 2014

AbstractTwo chiral carboxylic acid functionalized micro‐ and mesoporous metal–organic frameworks (MOFs) are constructed by the stepwise assembly of triple‐stranded heptametallic helicates with six carboxylic acid groups. The mesoporous MOF with permanent porosity functions as a host for encapsulation of an enantiopure organic amine catalyst by combining carboxylic acids and chiral amines in situ through acid–base interactions. The organocatalyst‐loaded framework is shown to be an efficient and recyclable heterogeneous catalyst for the asymmetric direct aldol reactions with significantly enhanced stereoselectivity in relative to the homogeneous organocatalyst.
Effect of a small amount of sulfur on the physical and mechanical properties of peroxide‐cured fully saturated HNBR compounds
Authors: Sheng Chunrui , Hu Zhiwei , Martin Hoch , Duan Yongxin , Zhang Jianming 
Published: November 2014

ABSTRACTSulfur can be used as crosslink coagent in unsaturated elastomer. In this work, a fully saturated HNBR with 39 wt % nitrile content was selected to investigate the effect of a small amount of sulfur acting as crosslink coagent on the physical and mechanical properties of peroxide‐cured vulcanizates. First, selective cleavage of polysulfide (Sx) and monosulfide(S) bond by combined thiol‐piperidine treatment were performed and the existence of poly/monosulfide bond in sulfur‐contained HNBR compounds was verified. Then, no‐filler HNBR compounds with various content of sulfur were investigated to detect the influence of sulfur on the crosslink density and cure kinetics. The MDR results showed that the crosslink density of HNBR compounds reduced only when the amount of sulfur is 0.25 phr and above. Besides, the curing rate of no‐filler HNBR compounds increased with the increasing of the amount of sulfur and reached a maximum at a dosage of 0.25 phr sulfur. Finally, physical and mechanical properties of fully formulated compounds were evaluated and it was found that the addition of small amounts of sulfur in fully saturated HNBR compounds could improve the dynamic properties of peroxide‐cured HNBR compounds remarkably but at a cost of slightly higher compression set values and a small loss in heat aging resistance. In a conclusion, small amount of sulfur can impart the peroxide vulcanizates some “sulfide properties” like dynamic property, tensile strength, but at the same time, due to the introduction of sulfur, some “peroxide vulcanizates property” like heat‐resistance property, hot air resistance were weakened slightly. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41612.
Development of antibacterial silver treatments on HDPE nets for agriculture
Authors: De Simone Serena , Lombardi Fiorella Anna , Paladini Federica , Starace Giuseppe , Sannino Alessandro , Pollini Mauro 
Published: November 2014

ABSTRACTThe defense mechanism of crops associated with the use of polymeric nets and fabrics is only physical and, hence, ineffective against the bacterial contaminations. The presence of an antibacterial agent associated with the use of conventional agro‐textiles can represent a great advantage in the prevention of plant diseases and for food safety. The aim of this work was the development of antibacterial silver‐coated HDPE nets for an innovative application such as agriculture. Antibacterial coatings on high‐density polyethylene nets were obtained by a patented nanosilver deposition technique based on the in situ photo‐reduction of a silver solution. The concentration of silver deposited was defined by testing different silver solutions from a biological point of view. Moreover, in order to improve the adhesion of the silver coating to the substrate, the nets underwent low‐pressure plasma treatment before the silver deposition. The materials were characterized in terms of quality of the coating through scanning electron microscopy, and in terms of antibacterial capability on Gram positive and Gram negative bacteria through qualitative and quantitative microbiological tests. The most effective process parameters were defined and the importance of performing plasma pretreatment on this specific substrate was assessed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41623.
Modifying biodegradable plastics with additives based on condensed tannin esters
Authors: Grigsby Warren J. , Bridson James H. , Schrade Carmen 
Published: November 2014

ABSTRACTCondensed tannins derived from Pinus radiata bark have been esterified and added to biodegradable plastics as extrusion compounded functional plastic additives. The presence of longer alkyl chain hexanoate esters promoted tannin miscibility in the commercial polyesters Bionolle™ and Biopol™ whereas short chain acetate esters tended to remain as discrete domains, acting as fillers in the processed plastics. In the aliphatic polyester Bionolle the presence of tannin esters at typical plastic additive loadings did not alter plastic mechanical properties whereas at 5% content in Biopol the tannin‐additives reduced both flexural and tensile properties. Similarly tannin esters do not alter the melt or glass transition temperatures of the polyesters, but tannin hexanoate at 5% can influence the crystallization temperatures. Artificially aging plastics realized the functionality these plant extracts can impart to plastics in acting to reduce ultraviolet (UV)‐induced plastic degradation. Results indicate the tannin‐additives likely provide a stabilising role through inhibiting UV penetration into the plastic, with color analysis suggesting the tannin moiety itself was sacrificial and preferentially degrading. The imparted UV stability was linked to the dissolution of tannin esters in the plastic with longer chain esters providing greater protection against UV degradation. Tannin esters showed potential as functional additives for biodegradable polymers enhancing the UV stability of the plastic. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41626.
Synthesis and Antiaromatic Properties of Highly Planar Dithiaamethyrin
Authors: Ishimaru Yoshihiro , Shimoyama Naoyuki , Fujihara Takashi , Watanabe Keigo , Setsune Jun‐ichiro 
Published: November 2014

Abstract2,5‐Bis(4‐propyl‐2‐pyrrolyl)thiophene was reacted with aryl aldehydes to afford large porphyrinoids; [24]dithiaamethyrin(1.0.0.1.0.0) and [36]trithianonaphyrin(1.0.0.1.0.0.1.0.0). X‐ray crystallography of the dithiaamethyrin revealed a highly planar ring structure with mean plane deviation (MPD) value of 0.053 Å. A large positive NICS(0) value (+13.9 ppm) calculated for this planar 24π system unambiguously indicates an antiaromatic character that is consistent with a remarkably low field 1H chemical shift of the inner NH proton at 24.0 ppm. The magnitude of the paratropic ring current effect in the 24π amethyrin framework in the free base form and the diprotonated form was discussed on the basis of the MPD value and the NICS value. The present dithiaamethyrin is much more strongly antiaromatic than the dodecaalkylamethyrin in their free base forms, but the order inversed in their diprotonated forms.
Dynamic Slicing of Petri Nets Based on Structural Dependency Graph and its Application in System Analysis
Authors: Yu Wangyang , Ding Zhijun , Fang Xianwen 
Published: November 2014

AbstractPetri net models are frequently complex and difficult to understand and modify. Slicing technology is very useful in analyzing programs, and has been widely used in specification level for model reduction. So it is necessary to explore slicing methods for Petri nets. This paper proposes a dynamic slicing technique for Petri nets based on the structural dependency graph (SDG). Firstly, the SDG is constructed from the slicing criterion by a backtracking algorithm. Secondly, based on the SDG and a given marking, the dynamic slice can be acquired. As a case study, the proposed method is applied to a control system, and a simulation tool is developed for validating this method and automatically generating the slice. The algorithms can be useful in automatically identifying the parts of the model that affect a state of interest, and provide the basic technical support for alleviating the difficulty of formal verification and analysis.
Determination of human albumin in serum and urine samples by constant‐energy synchronous fluorescence method
Authors: Madrakian Tayyebeh , Bagheri Habibollah , Afkhami Abbas 
Published: November 2014

AbstractA sensitive spectrofluorimetric method using constant‐energy synchronous fluorescence technique is proposed for the determination of human albumin without separation. In this method, no reagent was used for enhancement of the fluorescence signal of albumin in the solution. Effects of some parameters, such as energy difference between excitation and emission monochromators (ΔE), emission and excitation slit widths and scan rate of wavelength were studied and the optimum conditions were established. For this purpose factorial design and response surface method were employed for optimization of the effective parameters on the fluorescence signal. The results showed that the scan rate of the wavelength has no significant effect on the analytical signal. The calibration curve was linear in the range 0.1–220.0 µg mL–1 of albumin with a detection limit of 7.0 × 10–3 µg mL–1. The relative standard deviations (RSD) for six replicate measurements of albumin were calculated as 2.2%, 1.7% and 1.3% for 0.5, 10.0 and 100.0 µg mL–1 albumin, respectively. Furthermore the proposed method has been employed for the determination of albumin in human serum and urine samples. Copyright © 2014 John Wiley & Sons, Ltd.
Simultaneous determination of a novel oral Janus kinase inhibitor ASP015K and its sulfated metabolite in rat plasma using LC‐MS/MS
Authors: Oda Kazuo , Mera Katsumi , Nagasaka Yasuhisa , Tokoro Kazumi 
Published: November 2014

AbstractA sensitive and selective liquid chromatography with tandem mass spectrometry (LC‐MS/MS) was developed for determining the concentrations of novel Janus kinase inhibitor ASP015K and its sulfated metabolite M2 in rat plasma. This method involves solid‐phase extraction (SPE) from 25 μL of rat plasma. LC separation was performed on an Inertsil PH‐3 column (100 mm L ×4.6 mm I.D., 5 µm) with a mobile phase consisting of 10 mM ammonium acetate and methanol under linear gradient conditions. Analytes were introduced to the LC‐MS/MS through an electrospray ionization source and detected in positive‐ion mode using selected reaction monitoring. Standard curves were linear from 0.25 to 500 ng/mL (r ≥0.9964). This assay enabled quantification of ASP015K and M2 at a concentration as low as 0.25 ng/mL in rat plasma. Validation data demonstrated that the method is selective, sensitive and accurate. Further, we also successfully applied this method to a preclinical pharmacokinetic study in rats. Copyright © 2014 John Wiley & Sons, Ltd.
Rationale and study design of the RESERVOIR trial: A randomized trial comparing reservoir‐based polymer‐free amphilimus‐eluting stents versus everolimus‐eluting stents with durable polymer in patients with diabetes mellitus
Authors: Romaguera R. , Brugaletta S. , Gomez‐Lara J. , Pinar E. , Jiménez‐Quevedo P. , Gracida M. , Roura G. , Ferreiro J.L. , Teruel L. , Gómez‐Hospital J.A. , Montanya E. , Alfonso F. , Valgimigli M. , Sabate M. , Cequier A. 
Published: November 2014

BackgroundPatients with diabetes mellitus (DM) remain at high risk for stent restenosis and adverse cardiovascular events in the drug‐eluting stent era. The amphilimus‐eluting stent (AES) is a third generation reservoir‐based polymer‐free drug‐eluting stent that has shown promising preliminary results in patients with DM. It has been suggested that the formulation of the drug with fatty acids could not only modulate the drug release in a timely manner but also achieve convenient levels of drug concentration in diabetic cardiac cells. The aim of this trial is to assess the efficacy of the AES in patients with DM compared with the cobalt chromium everolimus‐eluting stent with non‐erodible polymer (EES).Study DesignThis is an investigator‐initiated, multicenter, randomized clinical trial, performed in patients with DM. A total of 112 diabetic patients receiving glucose‐lowering agents and requiring percutaneous revascularization of a de novo lesion will be randomized in a 1:1 fashion to receive AES or EES. The primary endpoint is the neointimal volume obstruction at 9 months, evaluated by optical coherence tomography. Secondary endpoints will include strut coverage, angiographic in‐stent late loss and clinical endpoints such as target vessel revascularization or probable/definite stent thrombosis. This study completed the inclusion in October 2013.ConclusionsThe RESERVOIR trial is an investigator‐initiated trial that will evaluate whether the polymer‐free AES is not inferior to the EES inhibiting the neointimal hyperplasia in patients with DM. These results are also expected to improve our knowledge of the neointimal healing process in this population (Clinicaltrials.gov number NCT01710748). © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.
A Rhodium Triphenylphosphine Catalyst for Alkene Hydrogenation Supported on Neat Superparamagnetic Iron Oxide Nanoparticles
Authors: Dehe Daniel , Wang Lei , Müller Melanie K. , Dörr Gunder , Zhou Zhou , Klupp‐Taylor Robin N. , Sun Yu , Ernst Stefan , Hartmann Martin , Bauer Matthias , Thiel Werner R. 
Published: November 2014

AbstractA phosphonic acid functionalized triphenylphosphine rhodium complex was synthesized and grafted onto neat superparamagnetic iron oxide nanoparticles. The material was investigated by elemental analysis, IR spectroscopy, thermogravimetric analysis, XRD, N2‐physisorption analyses, and TEM measurements. The obtained hybrid material could be used as a catalyst for the hydrogenation of alkenes with excellent yields and a broad substrate scope. The catalyst can be reused ten times without any loss of activity. According to the results from X‐ray absorption spectroscopy, it is likely that formation of Rh nanoparticles occurs during the reaction.
Strategy for Scaling‐up of a Microsieve Dispersion Reactor
Authors: Wang Kai , Lu Yangcheng , Luo Guangsheng 
Published: November 2014

AbstractFor the application of microreactors in industrial processes, more scaling‐up strategies are still required except of the original concept, the numbering‐up. A more maneuverable and economic approach, combining both similarity‐up and numbering‐up, is introduced as an example for an innovative strategy. CFD simulation is also applied to assist analysis and optimization of fluid distribution. Based on this concept, named similarity‐up + numbering‐up + simulation, a pilot‐plant microsieve dispersion minireactor used to proceed the reaction of cyclohexanecarboxylic acid and oleum is designed and tested experimentally. With the contribution of similarity‐up, the treating capacity of the core unit is significantly increased. Ten parallel units are integrated to form a correspondingly enhanced capacity of the microreactor which exhibits low pressure drop, stable operating performance, and excellent main product selectivity.
A Fluorescent Indicator for Imaging Lysosomal Zinc(II) with Förster Resonance Energy Transfer (FRET)‐Enhanced Photostability and a Narrow Band of Emission
Authors: Sreenath Kesavapillai , Yuan Zhao , Allen John R. , Davidson Michael W. , Zhu Lei 
Published: November 2014

AbstractWe demonstrate a strategy to transfer the zinc(II) sensitivity of a fluoroionophore with low photostability and a broad emission band to a bright and photostable fluorophore with a narrow emission band. The two fluorophores are covalently connected to afford an intramolecular Förster resonance energy transfer (FRET) conjugate. The FRET donor in the conjugate is a zinc(II)‐sensitive arylvinylbipyridyl fluoroionophore, the absorption and emission of which undergo bathochromic shifts upon zinc(II) coordination. When the FRET donor is excited, efficient intramolecular energy transfer occurs to result in the emission of the acceptor boron dipyrromethene (4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene or BODIPY) as a function of zinc(II) concentration. The broad emission band of the donor/zinc(II) complex is transformed into the strong, narrow emission band of the BODIPY acceptor in the FRET conjugates, which can be captured within the narrow emission window that is preferred for multicolor imaging experiments. In addition to competing with other nonradiative decay processes of the FRET donor, the rapid intramolecular FRET of the excited FRET‐conjugate molecule protects the donor fluorophore from photobleaching, thus enhancing the photostability of the indicator. FRET conjugates 3 and 4 contain aliphatic amino groups, which selectively target lysosomes in mammalian cells. This subcellular localization preference was verified by using confocal fluorescence microscopy, which also shows the zinc(II)‐enhanced emission of 3 and 4 in lysosomes. It was further shown using two‐color structured illumination microscopy (SIM), which is capable of extending the lateral resolution over the Abbe diffraction limit by a factor of two, that the morpholino‐functionalized compound 4 localizes in the interior of lysosomes, rather than anchoring on the lysosomal membranes, of live HeLa cells.
A Combined “Electrochemical–Frustrated Lewis Pair” Approach to Hydrogen Activation: Surface Catalytic Effects at Platinum Electrodes
Authors: Lawrence Elliot J. , Blagg Robin J. , Hughes David L. , Ashley Andrew E. , Wildgoose Gregory G. 
Published: November 2014

AbstractHerein, we extend our “combined electrochemical–frustrated Lewis pair” approach to include Pt electrode surfaces for the first time. We found that the voltammetric response of an electrochemical–frustrated Lewis pair (FLP) system involving the B(C6F5)3/[HB(C6F5)3]− redox couple exhibits a strong surface electrocatalytic effect at Pt electrodes. Using a combination of kinetic competition studies in the presence of a H atom scavenger, 6‐bromohexene, and by changing the steric bulk of the Lewis acid borane catalyst from B(C6F5)3 to B(C6Cl5)3, the mechanism of electrochemical–FLP reactions on Pt surfaces was shown to be dominated by hydrogen‐atom transfer (HAT) between Pt, [PtH] adatoms and transient [HB(C6F5)3]⋅ electrooxidation intermediates. These findings provide further insight into this new area of combining electrochemical and FLP reactions, and proffers additional avenues for exploration beyond energy generation, such as in electrosynthesis.
High Relaxivity Mn2+‐Based MRI Contrast Agents
Authors: Regueiro‐Figueroa Martín , Rolla Gabriele A. , Esteban‐Gómez David , de Blas Andrés , Rodríguez‐Blas Teresa , Botta Mauro , Platas‐Iglesias Carlos 
Published: November 2014

AbstractStable Mn2+ mono‐ and binuclear complexes containing pentadentate 6,6′‐((methylazanediyl)bis(methylene))dipicolinic acid coordinating units give remarkably high relaxivities due to the presence of two inner‐sphere water molecules. The mononuclear derivative binds human serum albumin (HSA) with an association constant of 3372 M−1, which results in the replacement of the coordinated water molecules by donor atoms of protein residues. The dinuclear analogue also binds HSA while leaving one of the Mn2+ centres exposed to the solvent with two coordinated water molecules. Thus, this complex shows remarkably high relaxivities upon protein binding (39.0 mM−1 s−1 per Mn, at 20 MHz and 37 °C).
Photoinduced Charge Transfer in a Conformational Switching Chlorin Dimer–Azafulleroid in Polar and Nonpolar Media
Authors: Nikkonen Taru , Oliva María Moreno , Kahnt Axel , Muuronen Mikko , Helaja Juho , Guldi Dirk M. 
Published: November 2014

AbstractIn the present study, a biomimetic reaction center model, that is, a molecular triad consisting of a chlorin dimer and an azafulleroid, is synthesized and its photophysical properties are studied in comparison with the corresponding molecular dyad, which consists only of a chlorin monomer and an azafulleroid. As evidenced by 1H NMR, UV/Vis, and fluorescence spectroscopy, the chlorin dimer–azafulleroid folds in nonpolar media into a C2‐symmetric geometry through hydrogen bonding, resulting in appreciable electronic interactions between the chlorins, whereas in polar media the two chlorins diverge from contact. Femtosecond transient absorption spectroscopy studies reveal longer charge‐separated states for the chlorin dimer–azafulleroid; ≈1.6 ns in toluene, compared with the lifetime of ≈0.9 ns for the corresponding chlorin monomer–azafulleroid in toluene. In polar media, for example, benzonitrile, similar charge‐separated states are observed, but the lifetimes are inevitably shorter: 65 and 73 ps for the dimeric and monomeric chlorin–azafulleroids, respectively. Nanosecond transient absorption and singlet oxygen phosphorescence studies corroborate that in toluene, the charge‐separated state decays indirectly via the triplet excited state to the ground state, whereas in benzonitrile, direct recombination to the ground state is observed. Complementary DFT studies suggest two energy‐minima conformations, that is, a folded chlorin dimer–azafulleroid, which is present in nonpolar media, and another conformation in polar media, in which the two hydrophobic chlorins wrap the azafulleroid. Inspection of the frontier molecular orbitals shows that in the folded conformation, the HOMO on each chlorin is equivalent and is shared owing to partial π–π overlap, resulting in delocalization of the conjugated π electrons, whereas the wrapped conformation lacks this stabilization. As such, the longer charge‐separated lifetime for the dimer is rationalized by both the electron donor–acceptor separation distance and the stabilization of the radical cation through delocalization. The chlorin folding seems to change the photophysical properties in a manner similar to that observed in the chlorophyll dimer in natural photosynthetic reaction centers.
Water‐Soluble Molecularly Imprinted Nanoparticles (MINPs) with Tailored, Functionalized, Modifiable Binding Pockets
Authors: Awino Joseph K. , Zhao Yan 
Published: November 2014

AbstractConstruction of receptors with binding sites of specific size, shape, and functional groups is important to both chemistry and biology. Covalent imprinting of a photocleavable template within surface–core doubly cross‐linked micelles yielded carboxylic acid‐containing hydrophobic pockets within the water‐soluble molecularly imprinted nanoparticles. The functionalized binding pockets were characterized by their binding of amine‐ and acid‐functionalized guests under different pH values. The nanoparticles, on average, contained one binding site per particle and displayed highly selective binding among structural analogues. The binding sites could be modified further by covalent chemistry to modulate their binding properties.
Stereo‐ and Regioselective Phyllobilane Oxidation in Leaf Homogenates of the Peace Lily (Spathiphyllum wallisii): Hypothetical Endogenous Path to Yellow Chlorophyll Catabolites
Authors: Vergeiner Clemens , Ulrich Markus , Li Chengjie , Liu Xiujun , Müller Thomas , Kräutler Bernhard 
Published: November 2014

AbstractInvited for the cover of this issue is the group of Bernhard Kräutler at the University of Innsbruck, Austria. The image depicts the autumnal “disappearance” of chlorophyll and the ensuing rapid formation of colorless phyllobilins. Read the full text of the article at 10.1002/chem.201404783.