bluuebunny/crossref_metadata_2025_split huggingface dataset:
POSS‐based molecular hybrids with low dielectric constant: Effect of chemical structure and molecular architecture
Authors: Ke Fuyou , Zhang Chao , Guang Shanyi , Xu Hongyao , Lin Naibo 
Published: April 2015

ABSTRACTThree kinds of hybrids with different architectures including dumbbell‐type, bead‐type, and cross‐linked structure, were prepared via the Heck reaction between octavinyl‐polyhedral oligomeric silsesquioxane (OV‐POSS) and different bromo‐substituted aromatic amide monomers. The molecular architecture can be successfully achieved by simply varying the feed ratio of OV‐POSS to monomers. Their structure and properties were characterized by FTIR,1H NMR,29Si NMR, provide the expansion for FTIR and NMR] All the POSS‐based hybrids exhibited good thermal stability and low dielectric constant properties. The relationship between chemical structure, molecular architecture, and the dielectric constant of these hybrids were investigated in detail. The results show that POSS content dominated the low dielectric constant of the hybrids, while the chemical structure of organic chains and molecular architecture also play an important role on the formation of low dielectric constant. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 42292.
Characterization of a Pre‐Trajan Wall by Integrated Geophysical Methods
Authors: Orlando Luciana , Cardarelli Ettore , Cercato Michele , De Donno Giorgio 
Published: April 2015

AbstractThe purpose of this study was to characterize a pre‐Trajan mosaic‐decorated wall structure located beneath the Cryptoporticus of the ‘Baths of Trajan’ complex in Rome. The surveyed wall is 15 m long, 0.9 m wide and 3 to 5 m high. Ground penetrating radar (GPR) and P‐wave seismic refraction tomography profiles were used to reconstruct the wall's inner structure, generate a map of the fractures and to evaluate the seismic velocities of the building materials. The wall was surveyed with horizontally and vertically dense GPR profiles and two seismic lines. The seismic lines and GPR profiles were capable of detecting a discontinuity between brick and travertine materials that compose the wall. The combined interpretation of the two non‐invasive techniques allowed us to locate weak zones and fractures. This rapid, non‐destructive and multi‐parametric approach has proved to be effective for characterizing the current status of the wall and the results will be used by archaeologists to evaluate the wall's integrity and to preserve the structure in the future archaeological excavations. Copyright © 2015 John Wiley & Sons, Ltd.
Selective intraoperative cholangiography and risk of bile duct injury during cholecystectomy
Authors: Törnqvist B , Strömberg C , Akre O , Enochsson L , Nilsson M 
Published: April 2015

Abstract

Background
Whether intraoperative cholangiography can prevent iatrogenic bile duct injury during cholecystectomy remains controversial.

Methods
Data from the national Swedish Registry for Gallstone Surgery, GallRiks (May 2005 to December 2010), were analysed for evidence of iatrogenic bile duct injury during cholecystectomy. Patient- and procedure-related risk factors for bile duct injury with a focus on the rate of intended intraoperative cholangiography were analysed using multivariable logistic regression.

Results
A total of 51 041 cholecystectomies and 747 bile duct injuries (1·5 per cent) were identified; 9008 patients (17·6 per cent) were diagnosed with acute cholecystitis. No preventive effect of intraoperative cholangiography was seen in uncomplicated gallstone disease (odds ratio (OR) 0·97, 95 per cent c.i. 0·74 to 1·25). Operating in the presence (OR 1·23, 1·03 to 1·47) or a history (OR 1·34, 1·10 to 1·64) of acute cholecystitis, and open surgery (OR 1·56, 1·26 to 1·94), were identified as significant risk factors for bile duct injury. The intention to perform intraoperative cholangiography was associated with a reduced risk of bile duct injury in patients with concurrent (OR 0·44, 0·30 to 0·63) or a history of (OR 0·59, 0·35 to 1·00) acute cholecystitis.

Conclusion
Any proposed protective effect of intraoperative cholangiography was restricted to patients with (or a history of) acute cholecystitis.
A Stable Chemical SUMO1–Ubc9 Conjugate Specifically Binds as a Thioester Mimic to the RanBP2–E3 Ligase Complex
Authors: Sommer Stefanie , Ritterhoff Tobias , Melchior Frauke , Mootz Henning D. 
Published: April 2015

AbstractUbiquitin and ubiquitin‐like (Ubl) modifiers such as SUMO are conjugated to substrate proteins by E1, E2, and E3 enzymes. In the presence of an E3 ligase, the E2∼Ubl thioester intermediate becomes highly activated and is prone to chemical decomposition, thus making biochemical and structural studies difficult. Here we explored a stable chemical conjugate of the E2 enzyme from the SUMO pathway, Ubc9, with its modifier SUMO1 as a structural analogue of the Ubc9∼SUMO1 thioester intermediate, by introducing a triazole linkage by biorthogonal click chemistry. The chemical conjugate proved stable against proteolytic cleavage, in contrast to a Ubc9–SUMO1 isopeptide analogue obtained by auto‐SUMOylation. Triazole‐linked Ubc9–SUMO1 bound specifically to the preassembled E3 ligase complex RanBP2/RanGAP1*SUMO1/Ubc9, thus suggesting that it is a suitable thioester mimic. We anticipate interesting prospects for its use as a research tool to study protein complexes involving E2 and E3 enzymes.
Predicting the transition from juvenile delinquency to adult criminality: Gender‐specific influences in two high‐risk samples
Authors: Rhoades Kimberly A. , Leve Leslie D. , Eddy J. Mark , Chamberlain Patricia 
Published: April 2015

AbstractBackgroundMost juvenile offenders desist from offending as they become adults, but many continue and ultimately enter the adult corrections system. There has been little prospective examination of which variables may predict the latter transition, particularly for women.AimsOur aim was to find out, for men and women separately, what variables identifiable in adolescent offenders predict their continuation of offending into adult life.MethodsParticipants were 61 male and 81 female youths who had been referred from the juvenile justice system for chronic delinquency and recruited into randomised controlled trials comparing Multidimensional Treatment Foster Care with group care (‘treatment as usual’). All participants had attained adulthood by the time of our study. We first examined gender differences in childhood risk factors and then used Cox proportional‐hazards models to estimate the relationship of potential risk factors to first adult arrest.ResultsResults indicated that, for men, juvenile justice referrals alone predicted risk of any first adult arrest as well as arrest for felony arrest specifically. Each additional juvenile referral increased the risk of any adult arrest by 9% and of adult felony arrest by 8%. For women, family violence, parental divorce and cumulative childhood risk factors, but not juvenile justice referrals, were significant predictors of adult arrest. Each additional childhood risk factor increased the risk of adult arrest by 21%. Women who experienced parental divorce were nearly three times more likely to be arrested as an adult, and those who experienced family violence 2.5 times more so than those without such experiences.Conclusions and implications for practiceWe found preliminary evidence of gender differences in childhood risk factors for adult offending, and, thus potentially, for the development and use of interventions tailored differently for girls and boys and young men and young women to reduce their risk of becoming adult recidivists. Copyright © 2015 John Wiley & Sons, Ltd.
Synthesis of Phospholane–Phosphoramidite Ligands and their Application in Asymmetric Catalysis
Authors: Hammerer Tim , Leitner Walter , Franciò Giancarlo 
Published: April 2015

AbstractA set of phospholane–phosphoramidite ligands, which possess four elements of chirality, has been synthesized through a modular diastereoselective process. The ligands were applied in the Rh‐catalyzed asymmetric CC hydrogenation of several functionalized olefins with enantioselectivities of up to 99 % ee and a turnover frequency of up to 12 000 h−1, in the Rh‐catalyzed hydroformylation of vinyl arenes with enantioselectivities of up to 79 % ee, and in the Ir‐catalyzed asymmetric CN hydrogenation of different aryl imines with enantioselectivities of up to 79 % ee.
Vanadium Pentoxide Nanorods Anchored to and Wrapped with Graphene Nanosheets for High‐Power Asymmetric Supercapacitors
Authors: Li Ge , Wang Xiaolei , Hassan Fathy M. , Li Matthew , Batmaz Rasim , Xiao Xingcheng , Yu Aiping 
Published: April 2015

AbstractAsymmetric lithium‐ion supercapacitors have been obtaining great attention, owing to their significantly increased energy density. However, transition‐metal‐oxide‐based electrode materials with poor conductivity and sluggish electrode kinetics often sacrifice power performance and cycling stability. Herein, we report the in situ growth of V2O5 nanorods on highly conductive graphene sheets as anode materials with high specific capacitance and excellent rate capability, which is mainly attributed to the intimate contact between the nanorods and graphene sheets. The asymmetric supercapacitor based on graphene/V2O5 composites and activated carbon is fabricated and evaluated, where a high energy density of approximately 50 Wh kg−1 can be achieved at a power density of 136.4 W kg−1, as well as long cycling stability. This work provides an effective and efficient method for the fabrication of high‐performance asymmetric supercapacitors.
Ruthenium‐Catalyzed Oxidative Coupling of Primary Amines with Internal Alkynes through CH Bond Activation: Scope and Mechanistic Studies
Authors: Ruiz Sara , Villuendas Pedro , Ortuño Manuel A. , Lledós Agustí , Urriolabeitia Esteban P. 
Published: April 2015

AbstractThe oxidative coupling of primary amines with internal alkynes catalyzed by Ru complexes is presented as a general atom‐economy methodology with a broad scope of applications in the synthesis of N‐heterocycles. Reactions proceed through regioselective CH bond activation in 15 minutes under microwave irradiation or in 24 hours with conventional heating. The synthesis of 2,3,5‐substituted pyridines, benzo[h]isoquinolines, benzo[g]isoquinolines, 8,9‐dihydro‐benzo[de]quinoline, 5,6,7,8‐tetrahydroisoquinolines, pyrido[3,4g]isoquinolines, and pyrido[4,3g]isoquinolines is achievable depending on the starting primary amine used. DFT calculations on a benzylamine substrate support a reaction mechanism that consists of acetate‐assisted CH bond activation, migratory‐insertion, and CN bond formation steps that involve 28–30 kcal mol−1. The computational study is extended to additional substrates, namely, 1‐naphthylmethyl‐, 2‐methylallyl‐, and 2‐thiophenemethylamines.
Aminorhodamine (ARh): A Bichromophore with Three Emission Bands in Low Temperature Glasses
Authors: Sørensen Thomas Just , Kilså Kristine , Laursen Bo W. 
Published: April 2015

AbstractAt first glance, aminorhodamine (ARh) is a typical pH responsive fluorescent, rhodamine‐type dye. However, hidden under the typical rhodamine absorption band, ARh has another electronic transition of similar energy, but polarized orthogonal to that of the rhodamine chromophore. This transition—assigned to an arylpyrylium type chromophore contained in the system—is responsible for the sensor action of the dye. ARh is non‐fluorescent, while protonation of a donor amino group turn on a strong rhodamine‐type emission. At low temperature in frozen solution emission from both electronic subsystems of ARh are observed. In order to achieve more complete understanding of the photophysical mechanisms in this type of fluorescent probes, ARh and its protonated counterpart HARh were studied by absorption and fluorescence spectroscopy, computational chemistry, and at low temperatures in solid solution. Results from fluorescence anisotropy and time‐resolved fluorescence spectra establish a bichromophore model and suggest that a remarkable weak coupling between the two nearly isoenergetic excited states in ARh enables the dual emission. All the complicated properties observed for ARh was accounted for by a bichromophore model describing the electronic system of ARh as a bichromophore constituted by a rhodamine and an arylpyrylium subsystem.
A New Simple Chromo‐fluorogenic Probe for NO2 Detection in Air
Authors: Juárez L. Alberto , Costero Ana M. , Sancenón Félix , Martínez‐Máñez Ramón , Parra Margarita , Gaviña Pablo 
Published: April 2015

AbstractA new chromo‐fluorogenic probe, consisting of a biphenyl derivative containing both a silylbenzyl ether and a N,N‐dimethylamino group, for NO2 detection in the gas phase has been developed. A clear colour change from colourless to yellow together with an emission quenching was observed when the probe reacted with NO2. A limit of detection to the naked eye of about 0.1 ppm was determined and the system was successfully applied to the detection of NO2 in realistic atmospheric conditions.
Enantiogroup‐Differentiating Biocatalytic Reductions of Prochiral Cs‐Symmetrical Dicarbonyl Compounds to meso Compounds
Authors: Skoupi Marc , Vaxelaire Carine , Strohmann Carsten , Christmann Mathias , Niemeyer Christof M. 
Published: April 2015

AbstractThe stereoselective reduction of symmetrical prochiral dicarbonyl compounds bearing enantiotopic carbonyl groups yields several stereogenic centers in one step. In a proof‐of‐concept study, a new approach is described for the enzymatic desymmetrization of 5‐nitrononane‐2,8‐dione via sequential biocatalytic reduction steps utilizing ketoreductases to yield all possible diastereomers of 5‐nitrononane‐2,8‐diol.
Enantioseparation on Riboflavin Derivatives Chemically Bonded to Silica Gel as Chiral Stationary Phases for HPLC
Authors: Kumano Daisuke , Iwahana Soichiro , Iida Hiroki , Shen Chengshuo , Crassous Jeanne , Yashima Eiji 
Published: April 2015

AbstractAcetylated and/or 3,5‐dimethylphenylcarbamated riboflavins were prepared and the resulting riboflavin derivatives as well as natural riboflavin were regioselectively immobilized on silica gel through chemical bonding at the 5’‐O‐ or 3‐N‐position of the riboflavin to develop novel chiral stationary phases (CSPs) for enantioseparation by high‐performance liquid chromatography (HPLC). The chiral recognition abilities of the obtained CSPs were significantly dependent on the structures of the riboflavin derivatives, the position of the chemical bonding on the silica gel, and the structures of the racemic compounds. The CSPs bonded at the 5’‐O‐position on the silica gel tended to well separate helicene derivatives, while the CSPs bonded at the 3‐N‐position composed of acetylated and 3,5‐dimethylphenylcarbamated riboflavins showed a better resolving ability toward helicene derivatives and bulky aromatic racemic alcohols, respectively, and some of them were completely separated into the enantiomers. The observed difference in the chiral recognition abilities of these riboflavin‐based CSPs is discussed based on the difference in their structures, including the substituents of riboflavin and the positions immobilized on the silica gel. Chirality 27:507–517, 2015. © 2015 Wiley Periodicals, Inc.
Long‐term neuroplasticity of the face primary motor cortex and adjacent somatosensory cortex induced by tooth loss can be reversed following dental implant replacement in rats
Authors: Avivi‐Arber Limor , Lee Jye‐Chang , Sood Mandeep , Lakschevitz Flavia , Fung Michelle , Barashi‐Gozal Maayan , Glogauer Michael , Sessle Barry J. 
Published: April 2015

AbstractTooth loss is common, and exploring the neuroplastic capacity of the face primary motor cortex (face‐M1) and adjacent primary somatosensory cortex (face‐S1) is crucial for understanding how subjects adapt to tooth loss and their prosthetic replacement. The aim was to test if functional reorganization of jaw and tongue motor representations in the rat face‐M1 and face‐S1 occurs following tooth extraction, and if subsequent dental implant placement can reverse this neuroplasticity. Rats (n = 22) had the right maxillary molar teeth extracted under local and general anesthesia. One month later, seven rats had dental implant placement into healed extraction sites. Naive rats (n = 8) received no surgical treatment. Intracortical microstimulation (ICMS) and recording of evoked jaw and tongue electromyographic responses were used to define jaw and tongue motor representations at 1 month (n = 8) or 2 months (n = 7) postextraction, 1 month postimplant placement, and at 1–2 months in naive rats. There were no significant differences across study groups in the onset latencies of the ICMS‐evoked responses (P > 0.05), but in comparison with naive rats, tooth extraction caused a significant (P < 0.05) and sustained (1–2 months) decreased number of ICMS‐defined jaw and tongue sites within face‐M1 and ‐S1, and increased thresholds of ICMS‐evoked responses in these sites. Furthermore, dental implant placement reversed the extraction‐induced changes in face‐S1, and in face‐M1 the number of jaw sites even increased as compared to naive rats. These novel findings suggest that face‐M1 and adjacent face‐S1 may play a role in adaptive mechanisms related to tooth loss and their replacement with dental implants. J. Comp. Neurol. 523:2372–2389, 2015. © 2015 Wiley Periodicals, Inc.
Correlation between Energy and Spatial Distribution of Intragap Trap States in the TiO2 Photoanode of Dye‐Sensitized Solar Cells
Authors: Wang Yi , Wu Dapeng , Fu Li‐Min , Ai Xi‐Cheng , Xu Dongsheng , Zhang Jian‐Ping 
Published: April 2015

AbstractThe energy and spatial distribution of intragap trap states of the TiO2 photoanode of dye‐sensitized solar cells and their impact on charge recombination were investigated by means of time‐resolved charge extraction (TRCE) and transient photovoltage (TPV). The photoanodes were built from TiO2 nanospheroids with different aspect ratios, and the TRCE results allowed differentiation of two different types of trap states, that is, deep and shallow ones at the surface and in the bulk of the TiO2 particles, respectively. These trap states exhibit distinctly different characteristic energy with only a slight variation in the particle size, as derived from the results of the density of states. Analyses of the size‐dependent TPV kinetics revealed that in a moderate photovoltage regime of about 375–625 mV, the dynamics of electron recombination are dominated by shallow trap states in the bulk, which can be well accounted for by the mechanism of multiple‐trap‐limited charge transport.
Mechanochemical Sensing: A Biomimetic Sensing Strategy
Authors: Shrestha Prakash , Mandal Shankar , Mao Hanbin 
Published: April 2015

AbstractExisting biosensors employ two major components: analyte recognition and signal transduction. Although specificity is achieved through analyte recognition, sensitivity is usually enhanced through a chemical amplification stage that couples the two main units in a sensor. Although highly sensitive, the extra chemical amplification stage complicates the sensing protocol. In addition, it separates the two elements spatiotemporally, reducing the real‐time response of the biosensor. In this review, we discuss the new mechanochemical biosensors that employ mechanochemical coupling strategies to overcome these issues. By monitoring changes in the mechanical properties of a single‐molecule template upon analyte binding, single‐molecule sensitivity is reached. As chemical amplification becomes unnecessary in this single‐molecule mechanochemical sensing (SMMS) strategy, real‐time sensing is achieved.
Theoretical Computer‐Aided Mutagenic Study on the Triple Green Fluorescent Protein Mutant S65T/H148D/Y145F
Authors: Armengol Pau , Gelabert Ricard , Moreno Miquel , Lluch José M. 
Published: April 2015

AbstractGreen fluorescent protein (GFP) mutant S65T/H148D has been proposed to host a photocycle that involves an excited‐state proton transfer between the chromophore (Cro) and the Asp148 residue and takes place in less than 50 fs without a measurable kinetic isotope effect. It has been suggested that the interaction between the unsuspected Tyr145 residue and the chromophore is needed for the ultrafast sub‐50 fs rise in fluorescence. To verify this, we have performed a computer‐aided mutagenic study to introduce the additional mutation Y145F, which eliminates this interaction. By means of QM/MM molecular dynamics simulations and time‐dependent density functional theory studies, we have assessed the importance of the Cro–Tyr145 interaction and the solvation of Asp148 and shown that in the triple mutant S65T/H148D/Y145F a significant loss in the ultrafast rise of the Stokes‐shifted fluorescence should be expected.
Coordination‐Resolved Spectrometrics of Local Bonding and Electronic Dynamics of Au Atomic Clusters, Solid Skins, and Oxidized Foils
Authors: Yu Wang , Bo Maolin , Huang Yongli , Wang Yan , Li Can , Sun Chang Q. 
Published: April 2015

AbstractBy using combination of bond‐order–length–strength (BOLS) correlation, the tight‐binding (TB) approach, and zone‐selective photoelectron spectroscopy (ZPS), we were able to resolve local bond relaxation and the associated 4f7/2 core‐level shift of Au atomic clusters, Au(100, 110, 111) skins, and Au foils exposed to ozone for different lengths of time. In addition to quantitative information, such as local bond length, bond energy, binding‐energy density, and atomic cohesive energy, the results confirm our predictions that bond‐order deficiency shortens and stiffens the bond between undercoordinated atoms, which results in local densification and quantum entrapment of bonding electrons. The entrapment perturbs the Hamiltonian, and hence, shifts the core‐level energy accordingly. ZPS also confirms that oxidation enhances the effect of atomic undercoordination on the positive 4f7/2 energy shift, with the associated valence electron polarization contributing to the catalytic ability of undercoordinated Au atoms.
Solventless Formation of G‐Quartet Complexes Based on Alkali and Alkaline Earth Salts on Au(111)
Authors: Zhang Chi , Wang Likun , Xie Lei , Kong Huihui , Tan Qinggang , Cai Liangliang , Sun Qiang , Xu Wei 
Published: April 2015

AbstractTemplate cations have been extensively employed in the formation, stabilization and regulation of structural polymorphism of G‐quadruplex structures in vitro. However, the direct addition of salts onto solid surfaces, especially under ultra‐high‐vacuum (UHV) conditions, to explore the feasibility and universality of the formation of G‐quartet complexes in a solventless environment has not been reported. By combining UHV‐STM imaging and DFT calculations, we have shown that three different G‐quartet‐M (M: Na/K/Ca) complexes can be obtained on Au(111) using alkali and alkaline earth salts as reactants. We have also identified the driving forces (intra‐quartet hydrogen bonding and electrostatic ionic bonding) for the formation of these complexes and quantified the interactions involved. Our results demonstrate a novel route to fabricate G‐quartet‐related complexes on solid surfaces, providing an alternative feasible way to bring metal elements to surfaces for constructing metal–organic systems.