bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of the Nature of the CeO2 Support of the Rh Catalyst on Triggering the Oxidative Reforming of n‐Butane for H2 Production from Ambient Temperature
Authors: Sato Katsutoshi , Adachi Kouhei , Takita Yusaku , Nagaoka Katsutoshi
Published: February 2014

Three Rh catalysts supported on CeO2 with different specific surface areas and redox properties were prepared and evaluated for their ability to trigger the oxidative reforming of n‐butane from ambient temperature (≈300 K). The reference CeO2 catalysts supplied by the Catalyst Society of Japan (JRC‐CEO‐1, ‐3, and ‐4) were used as supports. Temperature‐programmed reduction and O2 titration measurements over the reduced catalysts indicated that a high number of surface CeO2 sites that were reducible below 573 K were present on the Rh/CEO‐3 catalyst; this catalyst had the largest specific surface area, and it generated sufficient heat by oxidizing CeO2−x [ΔH(298 K)=−368 kJ; x=0.5] after H2 reduction at 773 K. Furthermore, the temperature‐programmed reactions revealed that forming fine Rh particles on the high surface area of CEO‐3 lowers the autoignition temperature (498 K) of the oxidative reforming of n‐butane because the number of exposed Rh sites initiating reactions between n‐butane and O2 is large. Thus, the Rh/CEO‐3 catalyst could trigger the oxidative reforming of n‐butane at ambient temperature after H2 reduction at 773 K owing to the heat generated by the spontaneous oxidation of CeO2−x. In contrast, other catalysts could not trigger the reaction after reduction at the same temperature.
Improved Selectivity toward Light Olefins in the Reaction of Toluene with Methanol Over the Modified HZSM‐5 Catalyst
Authors: Bi Yi , Wang Yingli , Wei Yingxu , He Yanli , Yu Zhengxi , Liu Zhongmin , Xu Lei
Published: February 2014

Light olefins and para‐xylene were produced with high selectivity in the reaction of toluene with methanol over a modified HZSM‐5 catalyst. Ordered mesoporous structure and weaker acidic sites led to significant contribution to the selectivity toward para‐xylene. By means of a single‐pulse reaction and the temperature‐programmed surface reaction, it was confirmed that the presence of toluene and as‐produced xylene shortened the reaction induction period and reduced the formation temperature of ethylene and propylene, which was beneficial to improve the selectivity toward light olefins, particularly ethylene.
Rhodium Catalyzed ortho‐Cyanation of Arylphosphates with N‐cyano‐N‐phenyl‐p‐toluenesulfonamide
Authors: Gu Li‐Jun , Jin Cheng , Wang Rui , Ding Hong‐Yan
Published: February 2014

A rhodium‐catalyzed cyanation of chelation assisted CH bonds is described. This process provided a useful method for the preparation of diverse 2‐cyanated arylphosphonate and related compounds in good yields. The reaction tolerates a variety of synthetically important functional groups.
Fe3O4@SiO2–TEMPO as a Magnetically Recyclable Catalyst for Highly Selective Aerobic Oxidation of 5‐Hydroxymethylfurfural into 2,5‐Diformylfuran under Metal‐ and Halogen‐Free Conditions
Authors: Karimi Babak , Mirzaei Hamid M. , Farhangi Elham
Published: February 2014

A highly selective aerobic oxidation of 5‐hydroxymethylfurfural (5‐HMF) into 2,5‐diformylfuran (DFF) by employing a magnetically separable 2,2,6,6‐tetramethylpiperidine‐N‐oxide (TEMPO) catalyst (Fe3O4@SiO2–TEMPO) under metal‐ and halogen‐free conditions is described. Quantitative yields of DFF with excellent selectivities as high as >99 % were achieved under several versatile reaction conditions in a catalytic system consisting of Fe3O4@SiO2–TEMPO as a catalyst, tert‐butyl nitrite as a co‐catalyst, acetic acid as an additive, and toluene as a solvent. The results clearly demonstrate that the present catalytic system for selective conversion of 5‐HMF into DFF is comparable or even superior to the many systems based on transition‐metal catalysts. In addition, the catalyst can be successfully recovered and reused in five consecutive reaction runs by an external magnetic source with keeping its catalytic performance and selectivity.
Tracking “Apolar” NMe4+ Ions within Two Polyoxothiomolybdates that Have the Same Pores: Smaller Clathrate and Larger Highly Porous Clusters in Action
Authors: Korenev Vladimir S. , Boulay Antoine G. , Haouas Mohamed , Bannani Fatma , Fedin Vladimir P. , Sokolov Maxim N. , Terazzi Emmanuel , Garai Somenath , Müller Achim , Taulelle Francis , Marrot Jérôme , Leclerc Nathalie , Floquet Sébastien , Cadot Emmanuel
Published: February 2014

Two nanosized polyoxothiometalates were synthesized based on linking oxomolybdate building blocks with {Mo2O2S2}2+ groups. Remarkably, both compounds are formed selectively primarily upon changing the related concentrations in a logical way; they exhibit common structural features based on the same {Mo9O6S3}‐type pores, which result in connections between {Mo6O21} pentagons and {Mo2O2S2}2+ linkers. Whereas the much larger spherical Mo132‐type Keplerate contains twenty pores, the smaller Mo63‐type cluster remarkably contains only two. The two compounds and a similar Keplerate exhibit interesting supramolecular properties related to interactions with the unusual predominantly apolar NMe4+ cations. Structural characterization of the Mo63‐type compound reveals in the solid state a clathrate‐like species that contains four NMe4+ cations embedded in two types of structurally well‐adapted pockets. Related NMR spectroscopic investigations in solution using NMe4+ as the NMR spectroscopic probe are in agreement with the solid‐state description. 1H NMR spectroscopic experiments (1D variable‐temperature, 2D total correlation spectroscopy (TOCSY), exchange spectroscopy (EXSY), and diffusion‐ordered spectroscopy (DOSY)) feature firmly immobilized and mobile NMe4+ ions in relationship with the type of host–guest arrangements. The use of the 1H NMR DOSY spectroscopic methodology has been successfully applied to track the interactions of the NMe4+ cations with the {Mo9O6S3} pores of a sulfurated Keplerate, thereby allowing the first quantitative analysis of this type of plugging process. The stability constant K=(210±20) mol−1 L is discussed related to the character of the process.
Design of Thermally Stable Amine–Imine Nickel Catalyst Precursors for Living Polymerization of Ethylene: Effect of Ligand Substituents on Catalytic Behavior and Polymer Properties
Authors: Hu Haibin , Zhang Lei , Gao Haiyang , Zhu Fangming , Wu Qing
Published: February 2014

Nickel complexes bearing amine–imine ligands with various backbone substituents were synthesized and employed as ethylene polymerization catalysts on activation with Et2AlCl. The substituent on the backbone carbon atom of the amine moiety is decisive for the living nature of ethylene polymerization. A bulky amine–imine nickel precursor with a tert‐butyl group on the carbon atom of the amine group can polymerize ethylene in a living fashion at an elevated temperature of 65 °C, which is the highest temperature of living polymerization of ethylene with late transition‐metal catalysts. The wide applicable temperature range for living polymerization and sensitivity of the branch structure of the polyethylene to temperature enable precise synthesis of di‐ and triblock polyethylenes featuring different branched segments by sequential tuning of the polymerization temperature.
Mechanistic Studies of Hoveyda–Grubbs Metathesis Catalysts Bearing S‐, Br‐, I‐, and N‐coordinating Naphthalene Ligands
Authors: Grudzień Krzysztof , Żukowska Karolina , Malińska Maura , Woźniak Krzysztof , Barbasiewicz Michał
Published: February 2014

Derivatives of the Hoveyda–Grubbs complex bearing S‐, Br‐, I‐, and N‐coordinating naphthalene ligands were synthesized and characterized with NMR and X‐ray studies. Depending on the arrangement of the coordinating sites on the naphthalene core, the isomeric catalysts differ in activity in model metathesis reactions. In particular, complexes with the RuCH bond adjacent to the second aromatic ring of the ligand suffer from difficulties experienced on their preparation and initiation. The behavior most probably derives from steric hindrance around the double bond and repulsive intraligand interactions, which result in abnormal chemical shifts of benzylidene protons observed with 1H NMR. Furthermore EXSY studies revealed that the halogen‐chelated ruthenium complexes display an equilibrium, in which major cis‐Cl2 structures are accompanied with small amounts of isomeric forms. In general, contents of the minor forms, measured at 80 °C, correlate with the observed activity trends of the catalysts, although some exceptions complicate the mechanistic picture. We assume that for the family of halogen‐chelated metathesis catalysts the initiation mechanism starts with the cis‐Cl2⇌trans‐Cl2 isomerization, although further steps may become rate‐limiting for selected systems.
Preparation and Unique Electrical Behaviors of Monodispersed Hybrid Nanorattles of Metal Nanocores with Hairy Electroactive Polymer Shells
Authors: Cai Tao , Zhang Bin , Chen Yu , Wang Cheng , Zhu Chun Xiang , Neoh Koon‐Gee , Kang En‐Tang
Published: February 2014

A versatile template‐assisted strategy for the preparation of monodispersed rattle‐type hybrid nanospheres, encapsulating a movable Au nanocore in the hollow cavity of a hairy electroactive polymer shell (Au@air@PTEMA‐g‐P3HT hybrid nanorattles; PTEMA: poly(2‐(thiophen‐3‐yl)ethyl methacrylate; P3HT: poly(3‐hexylthiophene), was reported. The Au@silica core‐shell nanoparticles, prepared by the modified Stöber sol–gel process on Au nanoparticle seeds, were used as templates for the synthesis of Au@silica@PTEMA core‐double shell nanospheres. Subsequent oxidative graft polymerization of 3‐hexylthiophene from the exterior surface of the Au@silica@PTEMA core‐double shell nanospheres allowed the tailoring of surface functionality with electroactive P3HT brushes (Au@silica@PTEMA‐g‐P3HT nanospheres). The Au@air@ PTEMA‐g‐P3HT hybrid nanorattles were obtained after etching of the silica interlayer by HF. The as‐prepared nanorattles were dispersed into an electrically insulating polystyrene matrix and for the first time used to fabricate nonvolatile memory devices. As a result, unique electrical behaviors, including insulator behavior, write‐once‐read‐many‐times and rewritable memory effects, and conductor behavior as well, were observed in the Al/Au@air@PTEMA‐g‐P3HT+PS/ITO (ITO: indium‐tin oxide) sandwich thin‐film devices.
Alkyne/Alkene/Allene‐Induced Disproportionation of Cationic Gold(I) Catalyst
Authors: Kumar Manish , Jasinski Jacek , Hammond Gerald B. , Xu Bo
Published: February 2014

The first detailed experimental study of the deactivation of cationic gold was conducted, and the influence of each component in the reaction system (substrate, counterion, solvent) on the decay process was examined. It was found that a substrate (alkyne/allene/alkene)‐induced disproportionation of gold(I) may play a key role in the decay process. Our mechanism is supported by kinetic, XPS, voltammetry studies, and high‐resolution ESI‐MS data.
Supramolecular Polymers Self‐Assembled from trans‐Bis(pyridine) Dichloropalladium(II) and Platinum(II) Complexes
Authors: Chen Mingming , Wei Chengsha , Tao Jiaojiao , Wu Xibo , Huang Ningdong , Zhang Guobin , Li Liangbin
Published: February 2014

Two structurally similar trans‐bis(pyridine) dichloropalladium(II)‐ and platinum(II)‐type complexes were synthesized and characterized. They both self‐assemble in n‐hexane to form viscous fluids at lower concentrations, but form metallogels at sufficient concentrations. The viscous solutions were studied by capillary viscosity measurements and UV/Vis absorption spectra monitored during the disassembly process indicated that a metallophilic interaction was involved in the supramolecular polymerization process. For the two supramolecular assemblies, uncommon continuous porous networks were observed by using SEM and TEM revealed that they were built from nanofibers that fused and crosslinked with the increase of concentration. The xerogels of the palladium and platinum complexes were carefully studied by using synchrotron radiation WAXD and EXAFS. The WAXD data show close stacking distances driven by π–π and metal–metal interactions and an evident dimer structure for the platinum complex was found. The coordination bond lengths were extracted from fitting of the EXAFS data. Moreover, close PtII–PtII (PdII–PdII) and PtCl (PdCl) interactions proposed from DFT calculations in the reported oligo(phenylene ethynylene) (OPE)‐based palladium(II) pyridyl supramolecular polymers were also confirmed by using EXAFS. The PtII–PtII interaction is more feasible for supramolecular interaction than the PdII–PdII interaction in our simple case.
Transformation of a Cp*–Iridium(III) Precatalyst for Water Oxidation when Exposed to Oxidative Stress
Authors: Zuccaccia Cristiano , Bellachioma Gianfranco , Bortolini Olga , Bucci Alberto , Savini Arianna , Macchioni Alceo
Published: February 2014

The reaction of [Cp*Ir(bzpy)NO3] (1; bzpy=2‐benzoylpyridine, Cp*=pentamethylcyclopentadienyl anion), a competent water‐oxidation catalyst, with several oxidants (H2O2, NaIO4, cerium ammonium nitrate (CAN)) was studied to intercept and characterize possible intermediates of the oxidative transformation. NMR spectroscopy and ESI‐MS techniques provided evidence for the formation of many species that all had the intact Ir–bzpy moiety and a gradually more oxidized Cp* ligand. Initially, an oxygen atom is trapped in between two carbon atoms of Cp* and iridium, which gives an oxygen–Ir coordinated epoxide, whereas the remaining three carbon atoms of Cp* are involved in a η3 interaction with iridium (2 a). Formal addition of H2O to 2 a or H2O2 to 1 leads to 2 b, in which a double MeCOH functionalization of Cp* is present with one MeCOH engaged in an interaction with iridium. The structure of 2 b was unambiguously determined in the solid state and in solution by X‐ray single‐crystal diffractometry and advanced NMR spectroscopic techniques, respectively. Further oxidation led to the opening of Cp* and transformation of the diol into a diketone with one carbonyl coordinated at the metal (2 c). A η3 interaction between the three non‐oxygenated carbons of “ex‐Cp*” and iridium is also present in both 2 b and 2 c. Isolated 2 b and mixtures of 2 a–c species were tested in water‐oxidation catalysis by using CAN as sacrificial oxidant. They showed substantially the same activity than 1 (turnover frequency values ranged from 9 to 14 min−1).
Identification and Synthesis of Macrolide Pheromones of the Grain Beetle Oryzaephilus Surinamensis and the Frog Spinomantis Aglavei
Authors: Hötling Susann , Haberlag Birte , Tamm Matthias , Collatz Jana , Mack Patrick , Steidle Johannes L. M. , Vences Miguel , Schulz Stefan
Published: February 2014

Macrolide lactones, the so called cucujolides derived from unsaturated fatty acids, are aggregation pheromones of cucujid grain beetles. Thirty years ago, Oehlschlarger et al. showed that (3Z,6Z)‐dodeca‐3,6‐dien‐11‐olide (4) and the respective 12‐olide (7) attract the sawtoothed grain beetle Oryzaephilus surinamensis, whereas (5Z,8Z,13R)‐tetradeca‐5,8‐dien‐13‐olide (5) increases the response synergistically. The frass of this beetle is attractive for its parasitoid Cephalonomia tarsalis, which potentially can be used for pest control. A GC/MS analysis of attractive frass showed the presence of 5, together with an unknown isomer. Cucujolide V was tentatively identified also in the femoral glands, pheromone‐releasing structures, of the Madagascan mantelline frog Spinomantis aglavei. Therefore, a new route to synthesize doubly unsaturated macrolides allowing the flexible attachment of the side chain was developed. A straightforward method to obtain Z configured macrolides involves ring‐closing alkyne metathesis (RCAM) followed by Lindlar‐catalyzed hydrogenation. This methodology was extended to homoconjugated diene macrolides by using RCAM after introduction of one Z configured double bond in the precursor by Wittig reaction. A tungsten benzylidyne complex was used as the catalyst in the RCAM reaction, which afforded the products in high yield at room temperature. With the synthetic material at hand, the unknown isomer was identified as the new natural product (5Z,8Z,12R)‐tetradeca‐5,8‐dien‐12‐olide, cucujolide X (8). Furthermore, the route also allowed the synthesis of cucujolide V in good yield. The natural products were identified by the synthesis of enantiomerically pure or enriched material and gas chromatography on chiral phases. The new macrolide (R)‐8 proved to be biologically active, attracting female O. surinamensis, but no males. The synthetic material allowed the identification of (R)‐5 in both the beetle and the frog.
One‐Pot Synthesis of Pd‐Loaded SnO2 Yolk–Shell Nanostructures for Ultraselective Methyl Benzene Sensors
Authors: Hong Young Jun , Yoon Ji‐Wook , Lee Jong‐Heun , Kang Yun Chan
Published: February 2014

A continuous, single‐step, and large‐scale preparation of Pd‐catalyst‐loaded SnO2 yolk–shell spheres is demonstrated. These nanostructures show an unusually high response and selectivity to methyl benzenes, such as xylene and toluene, with very low cross‐responses to various interfering gases, making them suitable for precise monitoring of indoor air quality.
Azocinoindole Synthesis by a Gold(I)‐Catalyzed Ring Expansion of 2‐Propargyl‐β‐Tetrahydrocarboline
Authors: Zhang Lei , Chang Lina , Hu Hongwen , Wang Huaqin , Yao Zhu‐Jun , Wang Shaozhong
Published: February 2014

A new methodology taking advantage of gold(I)‐catalyzed ring expansion has been developed to assemble tricyclic 1H‐azocino[5,4‐b]indoles from 2‐propargyl‐β‐tetrahydrocarbolines. The azocinoindoles were obtained in moderate to excellent yields; the structure of which was established by X‐ray crystallographic analysis. A mechanism involving regioselective intramolecular hydroarylation, [1,2]‐alkenyl migration and carbon–carbon bond‐fragmentation was proposed.
A Versatile and Stereocontrolled Total Synthesis of Dihydroxylated Docosatrienes Containing a Conjugated E,E,Z‐Triene
Authors: Dayaker Gandrath , Durand Thierry , Balas Laurence
Published: February 2014

A versatile strategy featuring a Colvin rearrangement, hydrozirconation, a Sonogashira cross‐coupling reaction and a Z‐selective Wittig olefination, was successfully developed for the construction of a conjugated E,E,Z‐triene subunit, flanked on both sides by two Z‐allylic hydroxyl groups. This chemical pattern is found in many endogenous lipid metabolites such as maresin 1 (MaR1), neuroprotectin D1 (NPD1), and its aspirin triggered‐isomer AT‐NPD1, which not only counter‐regulate inflammation but also actively orchestrate (at nanomolar doses) the resolution and termination program of acute inflammation while promoting wound healing, return to homeostasis and neuroprotection. Unlike previous approaches, the advantages of the present strategy are obvious, as it allows us to modify the nonpolar tail, the carboxylated head or both ends of the molecule without repeating the whole synthetic sequence (about 26–34 steps according to the literature). Thus, the first total syntheses of NPD1 methyl ester epimer (which can also be considered as an enantiomer of AT‐NPD1) and its n‐3 docosapentaenoic acid derived analogue were achieved from a highly functionalized and late advanced pivotal intermediate. This innovative route may be easily adapted to gain access to other dihydroxylated metabolites and analogues of polyunsaturated fatty acids containing a conjugated E,E,Z‐triene subunit. Different epimers/diastereoisomers may be obtained by purchasing the suitable optically pure (S)‐ and/or (R)‐1,2,4‐butanetriol(s) as a chiral pool for both stereogenic centers.
Covalently Linked 5,15‐Diazaporphyrin Dimers: Promising Scaffolds for a Highly Conjugated Azaporphyrin π System
Authors: Matano Yoshihiro , Fujii Daisuke , Shibano Tarou , Furukawa Ko , Higashino Tomohiro , Nakano Haruyuki , Imahori Hiroshi
Published: February 2014

The first examples of β–β directly linked, acetylene‐bridged, and butadiyne‐bridged 5,15‐diazaporphyrin dimers have been prepared by palladium‐catalyzed coupling reactions of nickel(II) and copper(II) complexes of 3‐bromo‐10,20‐dimesityl‐5,15‐diazaporphyrin (mesityl=2,4,6‐trimethylphenyl). The effects of the linking modes and meso‐nitrogen atoms on the structural, optical, electrochemical, and magnetic properties of the distributed π systems were investigated by using X‐ray crystallography, UV/Vis absorption spectroscopy, DFT calculations, cyclic voltammetry, and ESR spectroscopy. Both the electronic and steric effects of the meso‐nitrogen atoms play an important role in the highly coplanar geometry of the directly linked dimers. The direct β–β linkage produces enhanced π conjugation and electron‐spin coupling between the two diazaporphyrin units.
Study on Distribution Features of Crustal Magnetic Anomalies Around Eastern Himalayan Syntaxis
Authors: Guo‐Fa KANG , Guo‐Ming GAO , Chun‐Hua BAI , Tian‐Yuan WANG , Yi‐Mi WANG , Teng ZHU
Published: February 2014

The Potsdam Magnetic Model of the Earth (POMME6.2) is used to investigate the spatial distribution of crustal magnetic anomalies around eastern Himalayan syntaxis and their decay with altitude. In order to study the different scales of magnetic anomalies, the two‐dimensional wavelet transform method is employed to decompose the ground magnetic anomalies. The relationship between magnetic anomaly and geological structure is also discussed. The results show that the distribution of crustal magnetic anomalies over study area is considerably non‐uniform. Relatively strong negative magnetic anomalies are distributed over Himalaya‐Eastern Syntaxis‐Longmen Mountains‐Daba Mountains, whereas positive magnetic anomalies are present over Sichuan Basin, with weaker magnetic anomalies over other regions. The eastern Himalaya syntaxis has important impact on magnetic anomalies around. All crustal magnetic anomalies over Eastern Syntaxis and the surrounding regions are medium‐ and short‐wavelength positive/negative ones superposed onto a negative or weak magnetic anomaly setting. These meso‐ and micro‐scale magnetic anomalies are generated from magnetic materials in the upper and middle crust, with strikes basically consistent with geological structures. Along Jinshajiang‐Honghe Fault Belt, there is a sharp weak magnetic anomaly belt. Longmenshan Fault Belt, Lijiang‐Xiaojinhe Fault Belt and Honghe Fault Belt are transitional zones between strong and weak magnetic anomalies. The east‐west magnetic anomalies in the central Tibetan Plateau exhibited arc shape in the dome of Eastern Syntaxis. The banded lumpy magnetic anomalies over the central Tibetan Plateau and Central Yunnan massif have the same decay rule.
Calculation of Coupling Coefficients for Component‐Type Borehole Strain Observations
Authors: Ling‐Kong ZHANG , An‐Fu NIU
Published: February 2014

Based on the mechanical model for strain measurement in double bushing boreholes, we deduce formulae of two coupling coefficients (A, B) of each strain component under plane stress state. This provides a basis for further determining values and directions of maximum and minimum principal strains of the crustal strain field, and has some significance for carrying out borehole strain observations of earthquakes, volcanoes and plate boundaries. Using a two‐ring model and the complex variable function method, we calculate the c (area strain response coefficient) and d (shear strain response factor), and demonstrate that there exist relationships c = 2A and d = 2B. And the variation curves of both are identical. Their physical meanings are coupling coefficients in the borehole for measurement of plane strain and shear strain in crust.
Long‐Period Tides and Global Earthquake Energy Release
Authors: Chao‐Di XIE , Xiao‐Ping WU , Xing‐Lin LEI , Wei MAO , Nan SUN
Published: February 2014

Using USGS global catalog of M ≥ 5.0 earthquakes between 1850 and 2012, a time series of global seismic energy is set up. The wavelet transform is applied to these time series in order to analyze their quasi‐period characteristics. The results show that the time series of global seismic energy contains three quasi‐periodicity components of 9‐year, 19‐year and 45‐year, and the 45‐year quasi periodicity is most prominent. Combined with the physical background of the periodicities of tidal forces, the correlations between long‐period tidal forces and quasi periodicity of seismic energy release are discussed. Quasi‐period component related to short‐periodic tides is not found in global seismic energy release.
Tau interconverts between diffusive and stable populations on the microtubule surface in an isoform and lattice specific manner
Authors: McVicker Derrick P. , Hoeprich Gregory J. , Thompson Andrew R. , Berger Christopher L.
Published: February 2014

It has been demonstrated that Tau exists on the microtubule lattice in both diffusing and static populations, but how this may relate to Tau function is currently unclear. Tau isoforms are developmentally regulated and have been shown to have disparate effects on microtubule polymerization, the ability to bind microtubules, and the ability to inhibit kinesin. It has also been shown that Tau is sensitive to microtubule stabilizing agents and the ability to affect the persistence length of microtubules and to inhibit kinesin can be altered by stabilizing microtubules with various nucleotide analogs. Given these observations, it is likely the behavior of Tau is dictated by both the isoform of Tau and by structural changes in the microtubule lattice. In the present study, we use single molecule imaging to examine the behavior of the three‐repeat short (3RS) isoform and the four‐repeat long (4RL) isoform on different microtubule tracks stabilized with either paclitaxel or guanylyl‐(α,β)‐methylene‐diphosphate (GMPCPP). On paclitaxel‐stabilized microtubules, we find 3RS‐Tau favors the static conformation and forms complexes consisting of 2–3 molecules, while 4RL‐Tau predominantly exists as a single molecule equally distributed between the static and diffusing populations. However, on GMPCPP‐stabilized microtubules both isoforms favor the diffusing conformation and do not form static complexes composed of more than one Tau molecule. We find both isoforms of Tau interconvert between static and diffusing populations on the microtubule surface, and the equilibrium between these two states depends on both the isoform of Tau and the structure of the underlying microtubule lattice. © 2014 Wiley Periodicals, Inc.
Phosphorylation of α‐tubulin by protein kinase C stimulates microtubule dynamics in human breast cells
Authors: De Shatarupa , Tsimounis Areti , Chen Xiangyu , Rotenberg Susan A.
Published: February 2014

Protein kinase C (PKC) engenders motility through phosphorylation of α‐tubulin at Ser‐165 in nontransformed MCF‐10A cells. Live cell imaging explored the impact of PKC‐mediated phosphorylation on microtubule (MT) dynamics. MTs fluorescently labeled with GFP‐α‐tubulin were treated with diacylglycerol (DAG)‐lactone (a membrane‐permeable PKC activator), or cotransfected with a pseudophosphorylated S165D‐α6‐tubulin mutant. Each condition increased the dynamicity of MTs by stimulating the rate and duration of the growth phase and decreasing the frequency of catastrophe. In MDA‐MB‐231 metastatic breast cells where the intrinsic PKC activity is high, these MT growth parameters were also high but could be suppressed by expression of phosphorylation‐resistant S165N‐α6‐tubulin or by treatment with a pan‐PKC inhibitor (bis‐indoleylmaleimide). Subcellular fractionation and immunofluorescence of MCF‐10A cells showed that phosphorylation (via DAG‐lactone) or pseudophosphorylation of α6‐tubulin increased its partitioning into MTs as compared to controls, and produced longer, more stable MTs. Following expression of the plus‐end binding protein GFP‐EB1, DAG‐lactone accelerated the formation and increased the number of nascent MTs. Expression of S165D‐α6‐tubulin promoted Rac1 activation and Rac1‐dependent cell motility. These findings call attention to PKC‐mediated phosphorylation of α‐tubulin as a novel mechanism for controlling the dynamics of MTs that result in cell movement. © 2014 Wiley Periodicals, Inc.
Iron‐loaded PLLA nanoparticles as highly efficient intracellular markers for visualization of mesenchymal stromal cells by MRI
Authors: Vernikouskaya I. , Fekete N. , Bannwarth M. , Erle A. , Rojewski M. , Landfester K. , Schmidtke‐Schrezenmeier G. , Schrezenmeier H. , Rasche V.
Published: February 2014

Monitoring of the fate of cells after injection appears paramount for the further development of cell therapies. In this context magnetic resonance imaging (MRI) is increasing in relevance owing to its unique tissue visualization properties. For assessment of cell trafficking and homing, the cells have to be labeled to become MR visible. The rather low sensitivity of MRI demands dedicated intracellular markers with high payloads of MR contrast agents for ensuring sensitive detection of local cell aggregations. In the presented work the application of custom‐designed nanometer‐sized iron oxide loaded poly‐(l‐lactide) (iPLLA) nanoparticles was investigated. The particles were synthesized by the mini‐emulsion process and evaluated for labeling of mesenchymal stromal cells (MSCs). The efficient cellular uptake and long intracellular retention times of the particles as well as their nontoxicity are demonstrated. The average cellular iron content was 55 pg iron per cell. Further incorporation of, for example, fluorescent dye enables the generation of multireporter particles, providing the great potential for multimodal imaging. The efficiency of these nanoparticles as MRI contrast agent was evaluated in vitro using relaxation rate mapping, yielding relaxivities r2 = 273.3, r2* = 545.1 mm−1 s−1 at 3 T and r2 = 415.7, r2* = 872.3 mm−1 s−1 at 11.7 T. The high r2* relaxivity of the iPLLA nanoparticles enabled visualization of a single labeled cell in vitro at 50‐µm spatial resolution. In vivo evaluation in a rat injury model revealed the potential of the iPLLA particles to efficiently label MSCs for MRI monitoring of ~20 000–40 000 injected cells at 11.7 T. In conclusion the presented work demonstrates the applicability of iPLLA particles as efficient intracellular marker for MSC labeling for monitoring the fate of the cells by MRI. Copyright © 2014 John Wiley & Sons, Ltd.
Multimodal cell tracking of a spontaneous metastasis model: comparison between MRI, electron paramagnetic resonance and bioluminescence
Authors: Danhier Pierre , De Preter Géraldine , Magat Julie , Godechal Quentin , Porporato Paolo E. , Jordan Bénédicte F. , Feron Olivier , Sonveaux Pierre , Gallez Bernard
Published: February 2014

MRI cell tracking is a promising technique for tracking various cell types in living animals. Usually, cells are incubated with iron oxides so that the particles are taken up before the cells are injected in vivo. In the present study, we aimed to monitor migration of luciferase‐expressing mouse renal cancer cells (RENCA‐luc) after intrarenal or intrasplenic injection. These cells were labelled using Molday Ion Rhodamine B (MIRB) fluorescent superparamagnetic iron oxide particles. Their fate after injection was first assessed using ex vivo X‐band electron paramagnetic resonance (EPR) spectroscopy. This biodistribution study showed that RENCA‐luc cells quickly colonized the lungs and the liver after intrarenal and intrasplenic injection, respectively. Bioluminescence imaging (BLI) studies confirmed that this cell line preferentially metastasized to these organs. Early tracking of labelled RENCA‐luc cells in the liver using high‐field MRI (11.7 T) was not feasible because of a lack of sensitivity. MRI of MIRB‐labelled RENCA‐luc cells after injection in the left kidney was then performed. T2‐ and T2*‐weighted images showed that the labelled cells induced hypointense signals at the injection site. Nevertheless, the hypointense regions tended to disappear after several days, mainly owing to dilution of the MIRB iron oxides with cell proliferation. In conclusion, EPR is well adapted to ex vivo analysis of tissues after cell tracking experiments and allows short‐term monitoring of metastasizing cells. MRI is a suitable tool for checking labelled cells at their injection site, but dilution of the iron oxides owing to cell division remains a major limitation. BLI remains the most suitable technique for long‐term monitoring of metastatic cells. Copyright © 2014 John Wiley & Sons, Ltd.
A fast implementation of the first fit contiguous partitioning strategy for cubic topologies
Authors: Pascual Jose A. , Miguel‐Alonso Jose , Lozano Jose A.
Published: February 2014

In this paper, we propose and evaluate improved first fit (IFF), a fast implementation of the first fit contiguous partitioning strategy. It has been devised to accelerate the process of finding contiguous partitions in space‐shared parallel computers in which the nodes are arranged forming multidimensional cubic networks. IFF uses system status information to drastically reduce the cost of finding partitions with the requested shape. The use of this information, i combined with the early detection of zones where requests cannot be allocated, remarkably improves the search speed in large networks. An exhaustive set of simulation‐based experiments have been carried out to test IFF against other algorithms implementing the same partitioning strategy. Results, using synthetic and real workloads, show that IFF can be several orders of magnitude faster than competitor algorithms. Copyright © 2013 John Wiley & Sons, Ltd.
IR Probes of Protein Microenvironments: Utility and Potential for Perturbation
Authors: Adhikary Ramkrishna , Zimmermann Jörg , Dawson Philip E. , Romesberg Floyd E.
Published: February 2014

A variety of IR‐active moieties with absorptions that are distinct from those of proteins have been developed as probes of local protein environments, including carbon‐deuterium bonds (CD), cyano groups (CN), and azides (N3); however, no systematic analysis of their utility in a protein has been published. Previously, we characterized the N‐terminal Src homology 3 domain of the murine adapter protein Crk‐II (nSH3) with CD bonds site‐selectively incorporated throughout, and showed that it is relatively rigid and electrostatically heterogeneous and that it thermally unfolds under equilibrium conditions via a simple two‐state mechanism. We now report the synthesis and characterization of eight variants of nSH3 with CN and/or N3 probes at five of the same positions. In agreement with previous studies, the position‐dependent spectra suggest that both probes are predominantly sensitive to hydration, and not to their local electrostatic environments. Importantly, both probes also tend to significantly perturb the protein if they are not incorporated at surface‐exposed positions. Thus, unlike CD labels, which are both sensitive to their environment and non‐perturbative, CN and N3 probes should be used with caution.
Quantitative analysis of F‐actin redistribution in astrocytoma cells treated with candidate pharmaceuticals
Authors: Lockett Stephen , Verma Chrissie , Brafman Alla , Gudla Prabhakar , Nandy Kaustav , Mimaki Yoshihiro , Fuchs Philip L. , Jaja Joseph , Reilly Karlyne M. , Beutler John , Turbyville Thomas J.
Published: February 2014

Actin fibers (F‐actin) control the shape and internal organization of cells, and generate force. It has been long appreciated that these functions are tightly coupled, and in some cases drive cell behavior and cell fate. The distribution and dynamics of F‐actin is different in cancer versus normal cells and in response to small molecules, including actin‐targeting natural products and anticancer drugs. Therefore, quantifying actin structural changes from high resolution fluorescence micrographs is necessary for further understanding actin cytoskeleton dynamics and phenotypic consequences of drug interactions on cells. We applied an artificial neural network algorithm, which used image intensity and anisotropy measurements, to quantitatively classify F‐actin subcellular features into actin along the edges of cells, actin at the protrusions of cells, internal fibers and punctate signals. The algorithm measured significant increase in F‐actin at cell edges with concomitant decrease in internal punctate actin in astrocytoma cells lacking functional neurofibromin and p53 when treated with three structurally‐distinct anticancer small molecules: OSW1, Schweinfurthin A (SA) and a synthetic marine compound 23'‐dehydroxycephalostatin 1. Distinctly different changes were measured in cells treated with the actin inhibitor cytochalasin B. These measurements support published reports that SA acts on F‐actin in NF1−/− neurofibromin deficient cancer cells through changes in Rho signaling. Quantitative pattern analysis of cells has wide applications for understanding mechanisms of small molecules, because many anti‐cancer drugs directly or indirectly target cytoskeletal proteins. Furthermore, quantitative information about the actin cytoskeleton may make it possible to further understand cell fate decisions using mathematically testable models. Published 2014 Wiley Periodicals Inc.
Quantitative absorption cytometry for measuring red blood cell hemoglobin mass and volume
Authors: Schonbrun Ethan , Malka Roy , Di Caprio Giuseppe , Schaak Diane , Higgins John M.
Published: February 2014

We present an optical system, called the quantitative absorption cytometer (QAC), to measure the volume and hemoglobin mass of red blood cells flowing through a microfluidic channel. In contrast to clinical hematology analyzers, where cells are sphered in order for both volume and hemoglobin to be measured accurately, the QAC measures cells in their normal physiological shape. Human red blood cells are suspended in a refractive index‐matching absorbing buffer, driven through a microfluidic channel, and imaged using a transmission light microscope onto a color camera. A red and a blue LED illuminate cells and images at each color are used to independently retrieve cell volume and hemoglobin mass. This system shows good agreement with red blood cell indices retrieved by a clinical hematology analyzer and in fact measures a smaller coefficient of variation of hemoglobin concentration. In addition to cell indices, the QAC returns height and mass maps of each measured cell. These quantitative images are valuable for analyzing the detailed morphology of individual cells as well as statistical outliers found in the data. We also measured red blood cells in hypertonic and hypotonic buffers to quantify the correlation between volume and hemoglobin mass under osmotic stress. Because this method is invariant to cell shape, even extremely nonspherical cells in hypertonic buffers can be measured accurately. © 2014 International Society for Advancement of Cytometry
Sensory system development influences the ontogeny of eyeblink conditioning
Authors: Goldsberry Mary E. , Elkin Magdalyn E. , Freeman John H.
Published: February 2014

A rate‐limiting factor in the ontogeny of auditory eyeblink conditioning (EBC) is the development of sensory inputs to the pontine nucleus. One possible way to facilitate the emergence of EBC would be to use a conditioned stimulus (CS) that activates an earlier‐developing sensory system. The goal of the current study was to investigate whether using a vibration CS would facilitate the ontogeny of delay EBC relative to an auditory CS. Rat pups received six sessions of delay EBC or unpaired training using either a tone or vibration CS on postnatal day (P)14–15, 17–18, 21–22, or 24–25. Conditioning with a vibration CS resulted in rapid learning as early as P17–18, whereas conditioning with a tone CS did not result in rapid conditioning until after P17–18. Control experiments verified that the differences in EBC were due to CS‐specific sensory properties. The results suggest that the ontogeny of EBC depends on sensory system development. © 2014 Wiley Periodicals, Inc. Dev Psychobiol 56: 1244–1251, 2014.
Classification systems for lower extremity amputation prediction in subjects with active diabetic foot ulcer: a systematic review and meta‐analysis
Authors: Monteiro‐Soares M. , Martins‐Mendes D. , Vaz‐Carneiro A. , Sampaio S. , Dinis‐Ribeiro M.
Published: February 2014

Aim

We systematically review the available systems used to classify diabetic foot ulcers in order to synthesize their methodological qualitative issues and accuracy to predict lower extremity amputation, as this may represent a critical point in these patients' care.

Material and Methods

Two investigators searched, in EBSCO, ISI, PubMed and SCOPUS databases, and independently selected studies published until May 2013 and reporting prognostic accuracy and/or reliability of specific systems for patients with diabetic foot ulcer in order to predict lower extremity amputation.

Results

We included 25 studies reporting a prevalence of lower extremity amputation between 6% and 78%. Eight different diabetic foot ulcer descriptions and seven prognostic stratification classification systems were addressed with a variable (1–9) number of factors included, specially peripheral arterial disease (n = 12) or infection at the ulcer site (n = 10) or ulcer depth (n = 10). The Meggitt–Wagner, S(AD)SAD and Texas University Classification systems were the most extensively validated, whereas ten classifications were derived or validated only once. Reliability was reported in a single study, and accuracy measures were reported in five studies with another eight allowing their calculation. Pooled accuracy ranged from 0.65 (for gangrene) to 0.74 (for infection).

Conclusion

There are numerous classification systems for diabetic foot ulcer outcome prediction, but only few studies evaluated their reliability or external validity. Studies rarely validated several systems simultaneously and only a few reported accuracy measures. Further studies assessing reliability and accuracy of the available systems and their composing variables are needed. Copyright © 2014 John Wiley & Sons, Ltd.
Monitoring drug markets in the Internet age and the evolution of drug monitoring systems in Australia
Authors: Burns Lucy , Roxburgh Amanda , Bruno Raimondo , Van Buskirk Joe
Published: February 2014

In Australia, drug monitoring systems have been in place for more than a decade allowing for the measurement of ongoing trends in drug use and the detection of new drugs. The Drug Trends Unit at the National Drug and Alcohol Research Centre monitors drugs through four separate systems. The Illicit Drug Reporting System (IDRS) measures the price, purity, and availability of drugs that are primarily injected. The Ecstasy and Related Drugs Reporting System (EDRS) monitors psychostimulants that are used recreationally. The National Illicit Drugs Indicator Project (NIDIP) analyzes indicator data including drug‐related hospitalizations and deaths. Finally, the Drugs and Emerging Technologies Project (DNeT) analyzes the role of the Internet in the procurement and use of novel psychoactive substances. This paper provides an overview of each component of the system, demonstrating how the system has evolved over time. Copyright © 2014 John Wiley & Sons, Ltd.
Disease‐specific health status as a predictor of mortality in patients with heart failure: a systematic literature review and meta‐analysis of prospective cohort studies
Authors: Mastenbroek Mirjam H. , Versteeg Henneke , Zijlstra Wobbe P. , Meine Mathias , Spertus John A. , Pedersen Susanne S.
Published: February 2014

Aims

Some, but not all, studies have shown that patient‐reported health status, including symptoms, functioning, and health‐related quality of life, provides additional information to traditional clinical factors in predicting prognosis in heart failure patients. To evaluate the overall evidence, the association of disease‐specific health status on mortality in heart failure was examined through a systematic review and meta‐analysis.

Methods and results

Prospective cohort studies that assessed the independent association of disease‐specific health status with mortality in heart failure were selected. Searching PubMed (until March 2013) resulted in 17 articles in the systematic review and 17 studies in the meta‐analysis. About half of the studies reported a significant relationship between disease‐specific health status and mortality in heart failure, while the remainder found no association. A larger sample size increased the chance of identification of a significant association. The results of the meta‐analysis (including studies using a dichotomized heart failure‐specific health status variable as predictor) showed that heart failure patients reporting poor disease‐specific health status had a 39% increased risk of dying [hazard ratio 1.39 (1.25–1.54)] when compared with patients experiencing moderate or good disease‐specific health status.

Conclusion

Patient‐reported health status was an independent risk indicator for mortality in heart failure patients and may facilitate the identification of patients at high risk for poor prognosis above and beyond traditional risk variables. These findings suggest that patient‐reported health status should be routinely assessed in determining prognosis, as this information cannot be captured from patients' medical records.
Restoration of innate immune activation accelerates Th1‐cell priming and protection following pulmonary mycobacterial infection
Authors: Lai Rocky , Jeyanathan Mangalakumari , Shaler Christopher R. , Damjanovic Daniela , Khera Amandeep , Horvath Carly , Ashkar Ali A. , Xing Zhou
Published: February 2014

The immune mechanisms underlying delayed induction of Th1‐type immunity in the lungs following pulmonary mycobacterial infection remain poorly understood. We have herein investigated the underlying immune mechanisms for such delayed responses and whether a selected innate immune‐modulating strategy can accelerate Th1‐type responses. We have found that, in the early stage of pulmonary infection with attenuated Mycobacterium tuberculosis (M.tb H37Ra), the levels of infection in the lung continue to increase logarithmically until days 14 and 21 postinfection in C57BL/6 mice. The activation of innate immune responses, particularly DCs, in the lung is delayed. This results in a delay in the subsequent downstream immune responses including the migration of antigen‐bearing DCs to the draining lymph node (dLN), the Th1‐cell priming in dLN, and the recruitment of Th1 cells to the lung. However, single lung mucosal exposure to the TLR agonist FimH postinfection is able to accelerate protective Th1‐type immunity via facilitating DC migration to the lung and draining lymph nodes, enhancing DC antigen presentation and Th1‐cell priming. These findings hold implications for the development of immunotherapeutic and vaccination strategies and suggest that enhancement of early innate immune activation is a viable option for improving Th1‐type immunity against pulmonary mycobacterial diseases.