bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cooperative Catalysis of Noncompatible Catalysts through Compartmentalization: Wacker Oxidation and Enzymatic Reduction in a One‐Pot Process in Aqueous Media
Authors: Sato Hirofumi , Hummel Werner , Gröger Harald 
Published: February 2015

AbstractA Wacker oxidation using CuCl/PdCl2 as a catalyst system was successfully combined with an enzymatic ketone reduction to convert styrene enantioselectively into 1‐phenylethanol in a one‐pot process, although the two reactions conducted in aqueous media are not compatible due to enzyme deactivation by Cu ions. The one‐pot feasibility was achieved via compartmentalization of the reactions. Conducting the Wacker oxidation in the interior of a polydimethylsiloxane thimble enables diffusion of only the organic substrate and product into the exterior where the biotransformation takes place. Thus, the Cu ions detrimental to the enzyme are withheld from the reaction media of the biotransformation. In this one‐pot process, which formally corresponds to an asymmetric hydration of alkenes, a range of 1‐arylethanols were formed with high conversions and 98–99 % ee. In addition, the catalyst system of the Wacker oxidation was recycled 15 times without significant decrease in conversion.
Sulfates‐Based Nanothermites: An Expanding Horizon for Metastable Interstitial Composites
Authors: Comet Marc , Vidick Geoffrey , Schnell Fabien , Suma Yves , Baps Bernard , Spitzer Denis 
Published: February 2015

AbstractMetal sulfates (Ba, Bi, Ca, Cu, Mg, Mn, Na, Zn, Zr) were used as oxidizers in reactive compositions with Al nanopowder. These new kinds of nanothermites have outstandingly high reaction heats (4–6 kJ g−1) compared to conventional Al/metal oxides (1.5–4.8 kJ g−1) and also have good combustion velocities (200–840 m s−1 vs 100–2500 m s−1). These compositions are extremely insensitive to friction making their preparation and handling easy and safe. The sulfate hydration water increases the reaction heats and has a significant effect on the sensitivity to impact and to electrostatic discharge. The reaction of Al with water is easier to initiate than the one with sulfate which leads to two possible decomposition modes for samples exposed to an open flame. The pyrotechnical properties observed with sulfates have also been found for other sulfur oxygenates (SO32−, S2O32−, S2O82−) which opens up new horizons in the domain of metastable interstitial composites.
Tetracyanido(difluorido)phosphates M+[PF2(CN)4]−
Authors: Bresien Jonas , Ellinger Stefan , Harloff Jörg , Schulz Axel , Sievert Katharina , Stoffers Alrik , Täschler Christoph , Villinger Alexander , Zur Täschler Cornelia 
Published: February 2015

AbstractThe systematic study of the reaction of M[PF6] salts and Me3SiCN led to a synthetic method for the synthesis and isolation of a series of salts containing the unprecedented [PF2(CN)4]− ion in good yields. The reaction temperature, pressure, and stoichiometry were optimized. The crystal structures of M[PF2(CN)4] (M=[nBu4N]+, Ag+, K+, Li+, H5O2+) were determined. X‐ray crystallography showed the exclusive formation of the cis isomer in accord with 31P and 19F solution NMR spectroscopy data. Starting with the K[PF2(CN)4] the room temperature ionic liquid EMIm[PF2(CN)4] was prepared exhibiting a rather low viscosity.
Enhancing management effectiveness of invasive lionfish using distance sampling and detection probability
Authors: Tilley Alexander , Carter Elliott , Wassermann Sophia , López‐Angarita juliana 
Published: February 2015

AbstractInvasive lionfishPterois volitansandPterois milesare one of the greatest threats to coral reef fisheries in the Caribbean. Management currently relies solely on removal, however, there is little understanding of spatial ecology of lionfish to inform management strategies and thus, increase their effectiveness.The use of detection probability and population density estimates from distance sampling as a method to: (a) estimate spatial and depth variations in detectability of lionfish to prioritize removal efforts; (b) reduce costs related to removal in the Caribbean; and (c) provide quantifiable baseline data against which management success can be measured was evaluated.Underwater visual transect surveys were conducted at varying depths at four coral reef sites in the Turks and Caicos Islands using perpendicular distance sampling. Detection functions were fitted to distance data from 299 lionfish sightings across 37 transects to explore variation in detectability among survey sites and depths.Lionfish were detected with a 15.9% (12.2–20.6%) (mean ± 95% CI) probability across all sampling. Detection probability was significantly higher in depths < 15 m, however, lionfish density and mean size increased with depth. Population density on South Caicos reefs was estimated at 1679 (1140.4–2473.1) individuals per km2. Increased detection probability in shallower depths implies caution is needed in assessing management success at depth, and that removal methods and effort should be related specifically to depth and habitat factors.Distance sampling is an effective method for accurate estimation of lionfish population density and detection probability, providing metrics by which to identify priority management areas, and track population changes along with the success of removal efforts. As a result its integration into initial planning and continued monitoring aspects of lionfish management throughout the Caribbean is recommended.Copyright © 2015 John Wiley & Sons, Ltd.
What is the true nitrogenase reaction? A guided approach
Authors: Ipata Piero L. , Pesi Rossana 
Published: February 2015

AbstractOnly diazotrophic bacteria, called Rizhobia, living as symbionts in the root nodules of leguminous plants and certain free‐living prokaryotic cells can fix atmospheric N2. In these microorganisms, nitrogen fixation is carried out by the nitrogenase protein complex. However, the reduction of nitrogen to ammonia has an extremely high activation energy due to the stable (unreactive) NN triple bond. The structural and functional features of the nitrogenase protein complex, based on the stepwise transfer of eight electrons from reduced ferredoxin to the nitrogenase, coupled to the hydrolysis of 16 ATP molecules, to fix one N2 molecule into two NH3 molecules, is well understood. Yet, a number of different nitrogenase‐catalyzed reactions are present in biochemistry textbooks, which might cause misinterpretation. In this article, we show that when trying to balance the reaction catalyzed by the nitrogenase protein complex, it is important to show explicitly the 16 H+ released by the hydrolysis of the 16 ATP molecules needed to fix the atmospheric N2 © 2015 by the International Union of Biochemistry and Molecular Biology, 43(3):142–144, 2015.
Biodiesel: Sustainable Energy Replacement to Petroleum‐Based Diesel Fuel – A Review
Authors: Ajala Olawale E. , Aberuagba Folorunsho , Odetoye Temitope E. , Ajala Adejoke M. 
Published: February 2015

AbstractBiodiesel is a sustainable and renewable source of fuel. It has been considered as a comparable substitute to petro‐diesel, which is a fast depleting resource. Many studies have been undertaken on biodiesel production from various feedstock as a result of its importance. The differences between the physico‐chemical properties of biodiesel and petro‐diesel were considered with the aim of justifying the applicability of biodiesel in compression ignition engines (CIE). It was established that biodiesel has relatively close BTE (brake thermal efficiency) and BSFC (brake specific fuel consumption) values with petro‐diesel, hence, is suitable for CIE operation without any modification. The exhaust from CIE using biodiesel was lower compared to petro‐diesel and this confirms the environmental friendliness of biodiesel. The catalyst being an important substance in the transesterification reaction of vegetable oil/animal fat to produce biodiesel was comprehensively discussed, and heterogeneous catalysts were established to be preferred due to several advantages over homogenous catalysts. This paper reviews biodiesel production, prospects, benefits and challenges as a replacement for petrol diesel.
Rational Design of a β‐Glycosidase with High Regiospecificity for Triterpenoid Tailoring
Authors: Park Sang Jin , Choi Jung Min , Kyeong Hyun‐Ho , Kim Song‐Gun , Kim Hak‐Sung 
Published: February 2015

AbstractTriterpenoids with desired glycosylation patterns have attracted considerable attention as potential therapeutics for inflammatory diseases and various types of cancer. Sugar‐hydrolyzing enzymes with high substrate specificity would be far more efficient than other methods for the synthesis of such specialty triterpenoids, but they are yet to be developed. Here we present a strategy to rationally design a β‐glycosidase with high regiospecificity for triterpenoids. A β‐glycosidase with broad substrate specificity was isolated, and its crystal structure was determined at 2.0 Å resolution. Based on the product profiles and substrate docking simulations, we modeled the substrate binding modes of the enzyme. From the model, the substrate binding cleft of the enzyme was redesigned in a manner that preferentially hydrolyzes glycans at specific glycosylation sites of triterpenoids. The designed mutants were shown to produce a variety of specialty triterpenoids with high purity.
Generations: The old gives way to the new, and the new is too soon the old
Authors: Butman Samuel 
Published: February 2015

Key Points

This report highlights the importance of unique lesion characteristics (ostial RCA) with regard to outcomes
In practice, choosing the correct stent for the right lesion and patient does make a difference
New stent delivery systems, for specific subsets of lesions will continually need to be compared to optimize long‐term outcomes
Metal–Organic Frameworks: New Interlayer Dielectric Materials
Authors: Usman Muhammad , Mendiratta Shruti , Lu Kuang‐Lieh 
Published: February 2015

AbstractSome metal–organic frameworks (MOFs) with low dielectric constants, high thermal/mechanical stabilities, low leakage currents, and good comparability in devices can lead to integrated circuits, in which the MOF can act as an interlayer dielectric (ILD) material with tunable structural properties and high porosity. Based on initial research, in this Highlight, we propose a roadmap that can serve as a starting point for addressing the potential use of MOFs as ILD materials in the microelectronics industry, providing an effective path towards achieving remarkable new applications of dielectric MOFs in the future.
Sterically Hindered Luminescent PtII–Phosphite Complexes for Electroluminescent Devices
Authors: Mydlak Mathias , Yang Cheng‐Han , Polo Federico , Galstyan Anzhela , Daniliuc Constantin G. , Felicetti Michael , Leonhardt Jens , Strassert Cristian A. , De Cola Luisa 
Published: February 2015

AbstractPtII complexes with one bulky, sterically demanding, tertiary phosphite ancillary ligand and a coordinating chromophore are herein presented. The phosphite ligand, tris(2,4‐di‐tert‐butylphenyl) acts as a bidentate ligand coordinating the platinum ion through the central phosphorus atom and a cyclometalating carbon atom of one of the substituents. The two free phenoxy moieties lie above and below the coordination plane, leading to steric hindrance that avoids aggregation and provides solubility in organic solvents. The other two coordination sites on the central metal ion are occupied by a chromophoric ligand, which is responsible for the energy of the luminescent excited state. This separation of functions, on the two coordinated ligands, allows the use of a wider range of luminophores with good luminescent properties, maintaining the control of the intermolecular interactions with the non‐chromophoric ligand. Based on this approach we were able to achieve a bright deep blue emission (λ=444 nm, Φem=0.38) from a complex with a tailored ligand, which was then used for the fabrication of an electroluminescent device. In addition commercially available luminophores were also employed to synthesize green emitters.
On the Radical Nature of Iron‐Catalyzed Cross‐Coupling Reactions
Authors: Hedström Anna , Izakian Zakieh , Vreto Irma , Wallentin Carl‐Johan , Norrby Per‐Ola 
Published: February 2015

AbstractThe radical nature of iron‐catalyzed cross‐coupling between Grignard reagents and alkyl halides has been studied by using a combination of competitive kinetic experiments and DFT calculations. In contrast to the corresponding coupling with aryl halides, which commences through a classical two‐electron oxidative addition/reductive elimination sequence, the presented data suggest that alkyl halides react through an atom‐transfer‐initiated radical pathway. Furthermore, a general iodine‐based quenching methodology was developed to enable the determination of highly accurate concentrations of Grignard reagents, a capability that facilitates and increases the information output of kinetic investigations based on these substrates.
Access to New Endoperoxide Derivatives by Electrochemical Oxidation of Substituted 3‐Azabicyclo[4.1.0]hept‐4‐enes
Authors: Nuter Frédérick , Dimé Abdou Khadre Djily , Chen Cheng , Bounaadja Lotfi , Mouray Elisabeth , Florent Isabelle , Six Yvan , Buriez Olivier , Marinetti Angela , Voituriez Arnaud 
Published: February 2015

AbstractA series of substituted 3‐azabicyclo[4.1.0]hept‐4‐ene derivatives were prepared and analysed by cyclic voltammetry. Preparative aerobic electrochemical oxidation reactions were then carried out. Three original endoperoxides were isolated, characterised and subjected to antimalarial and cytotoxicity activity assays.
High Excimer‐State Emission of Perylene Bisimides and Recognition of Latent Fingerprints
Authors: Wang Ke‐Rang , Yang Zi‐Bo , Li Xiao‐Liu 
Published: February 2015

AbstractHigh excimer‐state emission in the H‐type aggregate of a novel asymmetric perylene bisimide derivative, 6, with triethyleneglycol chains and lactose functionalization was achieved in water. Furthermore, its application for enhancing the visualization of transfer latent fingerprints from glass slides to the poly(vinylidene fluoride) (PVDF) membrane was explored, which showed clear images of the latent fingerprint in daylight and under 365 nm ultraviolet illumination.
The Correlation of Electrochemical Measurements and Molecular Junction Conductance Simulations in β‐Strand Peptides
Authors: Horsley John R. , Yu Jingxian , Abell Andrew D. 
Published: February 2015

AbstractUnderstanding the electronic properties of single peptides is not only of fundamental importance, but it is also paramount to the realization of peptide‐based molecular electronic components. Electrochemical and theoretical studies are reported on two β‐strand‐based peptides, one with its backbone constrained with a triazole‐containing tether introduced by Huisgen cycloaddition (peptide 1) and the other a direct linear analogue (peptide 2). Density functional theory (DFT) and non‐equilibrium Green’s function were used to investigate conductance in molecular junctions containing peptides 3 and 4 (analogues of 1 and 2). Although the peptides share a common β‐strand conformation, they display vastly different electronic transport properties due to the presence (or absence) of the side‐bridge constraint and the associated effect on backbone rigidity. These studies reveal that the electron transfer rate constants of 1 and 2, and the conductance calculated for 3 and 4, differ by approximately one order of magnitude, thus providing two distinctly different conductance states and what is essentially a molecular switch. A definitive correlation of electrochemical measurements and molecular junction conductance simulations is demonstrated using two different charge transfer techniques. This study furthers our understanding of the electronic properties of peptides at the molecular level, which provides an opportunity to fine‐tune their molecular orbital energies through suitable structural manipulation.
Site‐Selective and Metal‐Free Aliphatic CH Oxidation Enabled Synthesis of [5,24,25‐D3]‐(25S)‐Δ7‐Dafachronic acid
Authors: Liu Weilong , Li Xiangke , Chen Jie , Li Tiemei , Dong Mengqiu , Lei Xiaoguang 
Published: February 2015

AbstractSteroid hormones play significant roles in both worms and mammalians. (25S)‐Δ7‐Dafachronic acid (Δ7‐DA, 1) is a member of the dafachronic acid hormonal series that regulates both development and lifespan of C. elegans. Despite its importance, effective tools for the illumination of its mode of action are lacking. Herein, we report an efficient synthesis of trideuterated Δ7‐DA, [5,24,25‐D3]‐(25S)‐Δ7‐dafachronic acid ([D3]‐Δ7‐DA, 2), as a useful chemical tool for subsequent biological studies. Key steps for this bioinspired synthesis approach include site‐selective aliphatic CH oxidation mediated by methyl(trifluoromethyl)dioxirane (TFDO), and the iridium/phosphine‐oxazoline‐catalyzed late‐stage asymmetric deuterium reduction.
Synthesis and Characterization of a Cu14 Hydride Cluster Supported by Neutral Donor Ligands
Authors: Nguyen Thuy‐Ai D. , Goldsmith Bryan R. , Zaman Homaira T. , Wu Guang , Peters Baron , Hayton Trevor W. 
Published: February 2015

AbstractThe copper hydride clusters [Cu14H12(phen)6(PPh3)4][X]2 (X=Cl or OTf; OTf=trifluoromethanesulfonate, phen=1,10‐phenanthroline) are obtained in good yields by the reaction of [(Ph3P)CuH]6 with phen, in the presence of a halide or pseudohalide source. The complex [Cu14H12(phen)6(PPh3)4][Cl]2 reacts with CO2 in CH2Cl2, in the presence of excess Ph3P, to form the formate complex [(Ph3P)2Cu(κ2‐O2CH)], along with [(phen)(Ph3P)CuCl].
A partially linear single‐index transformation model and its nonparametric estimation
Authors: Ding Xiaobo , Zhou Xiao‐Hua , Wang Qihua 
Published: February 2015

AbstractIn this paper, we consider the nonparametric estimation of the partially linear single‐index transformation model, where the transformation function, single‐index function and error distribution are all completely unknown. We first use the minimum average variance estimation method to estimate the regression coefficients, and then propose a new incorporated local linear regression estimator for the derivative function of the single‐index function. Accordingly by integration we can obtain the estimator of the single‐index function. Finally we propose a constrained least square estimator for the transformation function, where basis function approximation is employed and cross validation method is proposed to select suitable sets of basis functions. Asymptotical properties of the estimators are established. Simulation studies show that our proposed estimators work well. A real‐world data analysis of total health care charges was used to illustrate the proposed procedure. The Canadian Journal of Statistics 43: 97–117; 2015 © 2015 Statistical Society of Canada
In Vivo Targeting through Click Chemistry
Authors: Brudno Yevgeny , Desai Rajiv M. , Kwee Brian J. , Joshi Neel S. , Aizenberg Michael , Mooney David J. 
Published: February 2015

AbstractTargeting small molecules to diseased tissues as therapy or diagnosis is a significant challenge in drug delivery. Drug‐eluting devices implanted during invasive surgery allow the controlled presentation of drugs at the disease site, but cannot be modified once the surgery is complete. We demonstrate that bioorthogonal click chemistry can be used to target circulating small molecules to hydrogels resident intramuscularly in diseased tissues. We also demonstrate that small molecules can be repeatedly targeted to the diseased area over the course of at least one month. Finally, two bioorthogonal reactions were used to segregate two small molecules injected as a mixture to two separate locations in a mouse disease model. These results demonstrate that click chemistry can be used for pharmacological drug delivery, and this concept is expected to have applications in refilling drug depots in cancer therapy, wound healing, and drug‐eluting vascular grafts and stents.
The Unexpected Mechanism Underlying the High‐Valent Mono‐Oxo‐Rhenium(V) Hydride Catalyzed Hydrosilylation of CN Functionalities: Insights from a DFT Study
Authors: Wang Jiandi , Wang Wenmin , Huang Liangfang , Yang Xiaodi , Wei Haiyan 
Published: February 2015

AbstractIn this study, we theoretically investigated the mechanism underlying the high‐valent mono‐oxo‐rhenium(V) hydride Re(O)HCl2(PPh3)2 (1) catalyzed hydrosilylation of CN functionalities. Our results suggest that an ionic SN2‐Si outer‐sphere pathway involving the heterolytic cleavage of the SiH bond competes with the hydride pathway involving the CN bond inserted into the ReH bond for the rhenium hydride (1) catalyzed hydrosilylation of the less steric CN functionalities (phenylmethanimine, PhCH=NH, and N‐phenylbenzylideneimine, PhCH=NPh). The rate‐determining free‐energy barriers for the ionic outer‐sphere pathway are calculated to be ∼28.1 and 27.6 kcal mol−1, respectively. These values are slightly more favorable than those obtained for the hydride pathway (by ∼1–3 kcal mol−1), whereas for the large steric CN functionality of N,1,1‐tri(phenyl)methanimine (PhCPh=NPh), the ionic outer‐sphere pathway (33.1 kcal mol−1) is more favorable than the hydride pathway by as much as 11.5 kcal mol−1. Along the ionic outer‐sphere pathway, neither the multiply bonded oxo ligand nor the inherent hydride moiety participate in the activation of the SiH bond.
Oxidation‐State Analysis of Ceria by X‐ray Photoelectron Spectroscopy
Authors: Allahgholi Aschkan , Flege J. Ingo , Thieß Sebastian , Drube Wolfgang , Falta Jens 
Published: February 2015

AbstractThree different methods to determine the oxide‐phase concentration in mixed cerium oxide by hard X‐ray photoelectron spectroscopy are applied and quantitatively compared. Synchrotron‐based characterization of the O 1s region was used as a benchmark to introduce a method based on the weighted superposition of the Ce 3d spectra of the pure Ce3+ and Ce4+ phases, which was shown to lead to reliable and highly accurate determination of the mean oxidation state in mixed cerium oxides. The results obtained reveal a linear relation between the third distinct final state (u′′′) satellite peak intensity of the Ce4+ phase and the Ce4+ concentration by proper inclusion of Ce3+‐related plasmon satellite peaks, which contradicts previous claims of nonlinear behavior. In contrast, quantitative conventional peak‐fitting procedures were shown to be well suited for the Ce 2p region due to its relatively simple structure. Additional satellite features observed in the Ce 3d spectrum of CeO2 were proposed to originate from plasmon contributions.
Modification of the Optical Spectrum of Cytosine by the Formation of an Ordered Monolayer of Molecules at a Au(110)/Electrolyte Interface
Authors: Bowfield Andrew , Smith Caroline I. , Mansley Christopher P. , Weightman Peter 
Published: February 2015

AbstractAn analysis of the reflection anisotropy spectrum (RAS) of an ordered monolayer of cytosine adsorbed at a Au(110)/electrolyte interface is found to contain optical contributions from both the substrate and the cytosine. The spectrum of cytosine in an aqueous environment is significantly broadened by the interaction between the molecule and the Au(110). Successful simulations of the Au(110)/cytosine interface consisting of two additional molecular transitions, which sit in the middle of previously observed molecular absorption bands, are produced by an empirical Lorentzian transition model that is consistent with previous theoretical and experimental studies. While this analysis alone cannot determine the number of π→π* dipole transitions, it confirms that the only cytosine transitions that contribute to the optical response of the Au(110)/cytosine interface are located in the plane of the molecule, which is vertical to the gold surface with the long axis along the [1$\bar 1$0] direction.