bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dinitrogen Activation at Iron and Cobalt Metallalumatranes
Authors: Rudd P. Alex , Planas Nora , Bill Eckhard , Gagliardi Laura , Lu Connie C. 
Published: July 2013

AbstractAnionic cobalt and iron metallalumatranes that bind dinitrogen in an end‐on fashion were prepared and characterized by X‐ray crystallography. Along with literature‐known neutral cobalt and iron metallalumatranes, they form a quartet of low‐valent coordination complexes for comparing dinitrogen activation and functionalization at cobalt versus iron centers. In the anionic metallalumatranes, the metal atoms are proposed to have subvalent oxidation states of –1. The electronic structure of the anionic iron alumatrane, which was probed by electron paramagnetic resonance spectroscopy, Mössbauer spectroscopy, and density functional theory, is most consistent with Fe(–1)→Al(+3). Functionalization of dinitrogen was achieved by reaction of the ferrate alumatrane with 1,2‐bis(chlorodimethylsilyl)ethane and KC8 (1 equiv.) to generate an iron(II) disilylhydrazido complex. The transformation of dinitrogen to disilylhydrazido(2–) is an overall four‐electron process.
Efficient Aldol‐Type Reaction of O‐Protected α‐Hydroxy Aldehydes and N‐Trimethylsilyl Ketene Imines: Synthesis of β,γ‐Dihydroxy‐Nitriles
Authors: Long Sha , Panunzio Mauro , Qin Wenling , Bongini Alessandro , Monari Magda 
Published: July 2013

AbstractAn uncatalyzed aldol‐type reaction of aromatic N‐trimethylsilyl ketene imines with O‐protected α‐trialkylsilyloxy or α‐benzyloxy aldehydes is reported. It is shown that N‐trimethylsilyl ketene imines (SKIs) are essential for the success of this aldol‐type reaction, and that almost complete control of stereochemistry in the formation of the stereocentre vicinal to the stereogenic centre present in the starting aldehyde is seen when these compounds are used. A very high syn stereoselectivity was observed at room temperature, and a reversal of stereoselectivity to favour the formation of the anti product may be achieved at low temperature. Preliminary theoretical calculations support the hypothesis that the aldol‐type reaction is facilitated by the formation of a cyclic transition state, with concomitant silatropic migration from the ketene imine‐nitrogen to the aldehyde oxygen. The catalyst‐free aldol reaction has been applied to aromatic N‐trimethylsilyl ketene imines bearing two different aromatic groups. In these reactions, the diastereoselectivity for the stereocentre arising from aldehyde sp2 carbon remained extremely high, but the stereoselectivity for the formation of the new quaternary stereocentre was unsatisfactory.
Efficient Synthesis of Uracil‐Derived Hexa‐ and Tetrahydropyrido[2,3‐d]pyrimidines
Authors: Tolstoluzhsky Nikita , Nikolaienko Pavlo , Gorobets Nikolay , Van der Eycken Erik V. , Kolos Nadezhda 
Published: July 2013

AbstractA reaction of 6‐amino‐1,3‐dimethyluracil with 3‐(hetero)aroylacrylic acids and their methyl esters leads to hexahydropyrido[2,3‐d]pyrimidine‐5‐carboxylic acids or the corresponding methyl esters in high to excellent yields. One‐pot oxidation of the acid derivatives with CAN is accompanied by decarboxylation to give tetrahydropyrido[2,3‐d]pyrimidines, while oxidation with bromine resulted in the formation of tetrahydropyrido[2,3‐d]pyrimidine‐5‐carboxylic acids. The aromatization of methyl hexahydropyrido[2,3‐d]pyrimidine‐5‐carboxylates was achieved by K2CO3‐mediated air oxidation under ambient conditions.
Experimental determination of fire heat release rate with OC and CDG calorimetry for ventilated compartments fire scenario
Authors: Pretrel H. , Le Saux W. , Audouin L. 
Published: July 2013

ABSTRACTThis research deals with the experimental determination of the heat release rate (HRR) of fires in mechanically ventilated compartments based on oxygen consumption (OC) and carbon dioxide generation (CDG) calorimetry. It proposes formulations for fire in force‐ventilated compartments on the same basis as the relations established for hood calorimetry in an open atmosphere but considering inertia and unsteady behavior of the fire via the time variation mass of O2 and CO2 in the compartment. The value of the new formulations of HRR has been tested in two series of propane gas fire experiments performed in a large‐scale facility. The first series involves a fire scenario with one compartment, and the second series, a fire scenario with three compartments connected to each other by doorways. In the first test series, the OC and CDG formulations for HRR are assessed. In the second test series, the OC and CDG formulations are presented with two approaches to definition of the control volume: approach involving three rooms and the flow rate in the ventilation network and approach involving only the fire room and the flow rate through the doorways. On the basis of the fire experiments considered, the most accurate method (accuracy to within 10%) for determining the HRR is the CDG formulation with approach for the control volume without considering the flow rates at the doorways. This analysis points out the different features of each method (OC and CDG) and thoroughly discusses their advantages and drawbacks. The overall analysis allows guidelines to be formulated for fire HRR calculation in confined and ventilated compartments. Copyright © 2013 John Wiley & Sons, Ltd.
High‐order detached eddy simulation, zonal LES and URANS of cavity and labyrinth seal flows
Authors: Jefferson‐Loveday Richard J. , Nagabhushana Rao V. , Tyacke James C. , Tucker Paul G. 
Published: July 2013

SUMMARYHybrid numerical large eddy simulation (NLES), detached eddy simulation (DES) and URANS methods are assessed on a cavity and a labyrinth seal geometry. A high sixth‐order discretization scheme is used and is validated using the test case of a two‐dimensional vortex. The hybrid approach adopts a new blending function. For the URANS simulations, the flow within the cavity remains steady, and the results show significant variation between models. Surprisingly, low levels of resolved turbulence are observed in the cavity for the DES simulation, and the cavity shear layer remains two dimensional. The hybrid RANS–NLES approach does not suffer from this trait.For the labyrinth seal, both the URANS and DES approaches give low levels of resolved turbulence. The zonal Hamilton–Jacobi approach on the other had given significantly more resolved content. Both DES and hybrid RANS–NLES give good agreement with the experimentally measured velocity profiles. Again, there is significant variation between the URANS models, and swirl velocities are overpredicted. Copyright © 2013 John Wiley & Sons, Ltd.
An investigation of the role of sedimentation for stratospheric solar radiation management
Authors: Benduhn F. , Lawrence M. G. 
Published: July 2013

AbstractGravitational settling has been considered to be one of the limiting factors to stratospheric aerosol lifetime and therefore to the practicability and effectiveness of stratospheric solar radiation management (S‐SRM, which is one of the approaches being considered for planetary‐scale geoengineering or climate engineering). Given the property of numerical diffusion that is associated with sedimentation as a transport process on a discretized global grid, it is important to represent this process as accurately as possible. In this paper, newly developed sedimentation schemes are presented and validated against an analytical solution. Sensitivity studies with an aerosol chemistry general circulation model are conducted with monodisperse aerosol particles of fixed size and follow two main aims: first, to evaluate the relevance of sedimentation for the aerosol lifetime and distribution in the stratosphere as a function of particle size, and second, to explore the influence of numerical diffusion on these patterns. The relevance of sedimentation is explored further with respect to other relevant particle properties, such as shape and density. It is shown that the role of sedimentation in determining stratospheric particle lifetime is a complex function of all particle properties combined. Especially with respect to sulfate aerosol, the influence of sedimentation is conditioned by the temporal evolution of particle size. Although large enough particles for considerable sedimentation mediated removal are observed in the context of volcanic eruptions, it seems uncertain whether secondary particles of an equivalent size would be obtained in the context of S‐SRM, pointing to the need for an accurate representation of aerosol growth dynamics.
Characterization of a new pathovar of Agrobacterium vitis causing banana leaf blight in China
Authors: Huang Siliang , Long Mengling , Fu Gang , Lin Shanhai , Qin Liping , Hu Chunjin , Cen Zhenlu , Lu Jie , Li Qiqin 
Published: July 2013

AbstractA new banana leaf blight was found in Nanning city, China, during a 7‐year survey (2003–2009) of the bacterial diseases on banana plants. Eight bacterial strains were isolated from affected banana leaves, and identified as an intraspecific taxon of Agrobacterium vitis based on their 16S rDNA sequence similarities with those of 37 randomly selected bacterial strains registered in GenBank database. The representative strain Ag‐1 was virulent on banana leaves and shared similar growth and biochemical reactions with the reference strain IAM14140 of A. vitis. The strains causing banana leaf blight were denominated as A. vitis pv. musae. The traditional A. vitis strains virulent to grapevines were proposed to be revised as A. vitis pv. vitis. This is the first record of a new type of A. vitis causing banana leaf blight in China.
Modal‐based goal‐oriented error assessment for timeline‐dependent quantities in transient dynamics
Authors: Verdugo F. , Parés N. , Díez P. 
Published: July 2013

SUMMARYThis article presents a new approach to assess the error in specific quantities of interest in the framework of linear elastodynamics. In particular, a new type of quantities of interest (referred as timeline‐dependent quantities) is proposed. These quantities are scalar time‐dependent outputs of the transient solution, which are better suited to time‐dependent problems than the standard scalar ones, frozen in time. The proposed methodology furnishes error estimates for both the standard scalar and the new timeline‐dependent quantities of interest. The key ingredient is the modal‐based approximation of the associated adjoint problems, which allows efficiently computing and storing the adjoint solution.The approximated adjoint solution is readily post‐processed to produce an enhanced solution, requiring only one spatial post‐process for each vibration mode and using the time‐harmonic hypothesis to recover the time dependence. Thus, the proposed goal‐oriented error estimate consists in injecting this enhanced adjoint solution into the residual of the direct problem. The resulting estimate is very well suited for transient dynamic simulations because the enhanced adjoint solution is computed before starting the forward time integration of the direct problem. Thus, the cost of the error estimate at each time step is very low. Copyright © 2013 John Wiley & Sons, Ltd.
Graphene and graphite oxide based composites for application in energy systems
Authors: Singh Arvinder , Chandra Amreesh 
Published: July 2013

AbstractGraphene composites with metal or ceramics are being widely investigated for applications in electronic and energy devices. In this paper, we report the chemical synthesis of graphene and graphite oxide (GO)/ZnO‐Ag composites for application in energy storage devices, viz., supercapacitors (SCs). Results of surface modification and morphological studies carried out using Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) data are discussed. The electrochemical performance of these electrode materials in SCs have been investigated using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge‐discharge techniques. Performance of the GO/ZnO‐Ag composite has been compared with that of the pure graphene in terms of achievable energy and power density. Results show that opening of the GO sheets with ZnO spacer allows storage of more charge than achievable in pure graphene. Silver acts as a catalyst to enhance electrochemically active sites in the electrode material as well as helps in maintaining reasonable electronic conductivity. This is an important feature for the development of high performance SCs since GO/ZnO‐Ag composite is a low‐cost reproducible material in comparison to graphene.
Site‐dependent excited state absorption in Ce‐doped CaGa2S4 single crystal
Authors: Uchiki Hisao , Honma Shinsaku , Tanaka Kunihiko , Hidaka Chiharu , Takizawa Takeo 
Published: July 2013

AbstractExcited state absorption (ESA) by Ce3+ ions in the 5d1 lowest excited state in Ce‐doped CaGa2S4 single crystal was investigated by nanosecond two‐pulse pump‐CW probe spectroscopy. The first pump pulse of 425 nm excited the 4f ground state electron to the 5d1 first excited state and the second pump pulse of 589 nm was introduced at 13 ns after the first pump in order to selectively excite the 5d1 state. Transient intensity change of the CW probe of a diode laser of 780 nm was observed. Temporal behavior of photoluminescence intensity by the 5d1 to 4f state transition was also observed under excitation of the same two‐pulse pump.The experimental results can be explained by the model of site‐dependent excited state absorption. The photoluminescence is generated from the 5d1 states of Ce3+ at two sites with different decay time, whereas the excited state absorption takes place mainly from Ce3+ at one site as well as metastable Ce2+. The model predicts that optical gain by the 5d1 to 4f transition can be achieved by Ce3+ at the other site if the populations at both the 5d1 state of Ce3+ at the site resulting in ESA and Ce2+ can be bleached by simultaneous secondary optical pumping with an IR (e.g. Nd:YAG) laser. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
One‐move convertible nominative signature in the standard model
Authors: Liu Dennis Y. W. , Wong Duncan S. 
Published: July 2013

AbstractA nominative signature (NS) is a non‐self‐authenticating signature that is jointly generated by a signer (or a nominator) and a user (or a nominee), but once generated, its validity can only be determined by the user. No one else including the signer can tell the signature's validity unless the user confirms or disavows so, whereas the user cannot cheat either. One‐move NS is an efficient type of NS that requires the signer to send only one message to the user during the signature generation stage. Currently, there exists only one one‐move NS scheme that is proven secure in the standard model, and is convertible, that is, the user can transform a nominative signature to a publicly verifiable standard signature without the signer's aid. However, the number of elements in the keys of both signer and user grows linearly with the value of the security parameter. In this paper, we propose a new one‐move NS which is convertible, can be proven secure in the standard model, and also has a constant number of elements in the keys of both the signer and the user. We apply the Boneh–Boyen short standard signature in a novel way to build this nominative signature scheme. We show that this new scheme achieves the best performance among all the schemes proven secure in the standard model, and its security relies only on the standard q‐strong Diffie–Hellman and decisional Diffie–Hellman assumptions. Finally, we will present a generic construction by utilizing a secure standard signature scheme and a secure encryption scheme. Copyright © 2013 John Wiley & Sons, Ltd.
Posttraumatic Stress Symptoms and Cortisol Regulation in Mothers of Very Preterm Infants
Authors: Habersaat Stephanie , Borghini Ayala , Nessi Jennifer , Pierrehumbert Blaise , Forcada‐Guex Margarita , Ansermet François , Müller‐Nix Carole 
Published: July 2013

AbstractPrevious studies have found that mothers of very preterm infants often report symptoms of posttraumatic stress, which has been related to cortisol dysregulation. However, the exact nature of this association is not clear and can be different regarding the predominance of some specific symptoms of posttraumatic stress, as suggested by a recent model. The objective of the present study is to assess the association between diurnal salivary cortisol and posttraumatic stress symptoms in mothers of very preterm infants. Seventy‐four mothers of very preterm infants were included in the study. Mothers' cortisol regulation and posttraumatic stress symptoms were evaluated 12 months after child theoretical term (40 weeks of gestation). Results showed an association between higher re‐experiencing symptoms and flatter cortisol slopes. These results may help to understand differences found in studies assessing the relation between severity of posttraumatic stress and cortisol levels, by supporting the symptoms' theory. Copyright © 2013 John Wiley & Sons, Ltd.
Klinik und Genetik des familiären Brust- und Eierstockkrebses
Authors: Meindl A. , Rhiem K. , Engel C. , Ditsch N. , Kast K. , Hahnen E. , Schmutzler R.K. 
Published: July 2013

Zusammenfassung
Während mit der Entdeckung der Hochrisikogene „breast cancer 1“ (BRCA1) und „breast cancer 2“ (BRCA2) in den Jahren 1994/1995 die Erforschung des hereditären Mamma- und Ovarialkarzinoms zunächst beendet schien, belegen neuere Ergebnisse, dass das hereditäre Mamma- und Ovarialkarzinom eine extreme genetische Heterogenität aufweist. Die genetisch definierten Subtypen zeigen außerdem eine unterschiedliche phänotypische Ausprägung hinsichtlich der histopathologischen Charakteristika, des Krankheitsverlaufs und des Therapieansprechens. Dies erfordert eine Einbettung der Gendiagnostik in ein strukturiertes und standardisiertes Betreuungskonzept, das es erlaubt prospektive Daten zur Tumorinzidenz und zum Verlauf zu erfassen sowie in prospektiven Studien die Wertigkeit der verschiedenen diagnostischen, präventiven und neuen therapeutischen Optionen zu validieren. Das deutsche Konsortium widmet sich dieser Aufgabenstellung, um den betreffenden Familien effiziente Präventions- und Interventionsstrategien anbieten zu können. Dabei kommt der Zusammenarbeit mit der Selbsthilfe (http://www.BRCA-Netzwerk.de) mittlerweile eine große Bedeutung zu, die uns immer wieder vor Augen hält, wie wichtig es ist, den in diesem Artikel aufgeworfenen Fragestellungen nachzugehen.
Morbus Huntington und Huntington-ähnliche Erkrankungen
Authors: Nguyen H.P. 
Published: July 2013

Zusammenfassung
Der M. Huntington (Huntington-Chorea, Huntington disease, HD) ist die Hauptursache für eine hereditäre Chorea und ist gekennzeichnet durch die klinische Trias aus Bewegungsstörung, psychiatrischen Auffälligkeiten und kognitiven Leistungseinbußen. Neben der HD gibt es mehrere Erkrankungen, die mit einem HD-Phänotyp einhergehen und klinisch nur schwer von der HD zu unterscheiden sind, die sog. HD-ähnlichen Erkrankungen. Diese seltenen Erkrankungen wurden als HD-“like“(L)1 bis HDL4 bezeichnet. Mittlerweile sind pathogene Mutationen im Prionprotein(PRNP)-Gen (HDL1), im „Junctophilin“-3(JPH3)-Gen (HDL2) und im TATA-box-bindendes-Protein(TBP)-Gen (Synonym SCA17, HDL4) identifiziert worden. Darüber hinaus gibt es eine Reihe von Erkrankungen, die gelegentlich mit einem HD-Phänotyp imponieren, auch wenn i. d. R. andere Symptome vorherrschen. Diese Erkrankungen (u. a. spinozerebelläre Ataxien (SCA), dentatorubrale-pallidoluysiale Atrophie (DRPLA), Neuroferritinopathie, Chorea-Akanthozytose, benigne Chorea) müssen differenzialdiagnostisch in Betracht gezogen werden, wenn die HD bei einem Indexpatienten mit typischer Symptomatik molekulargenetisch nicht bestätigt werden kann. In diesem Artikel wird daher eine Übersicht über die wichtigsten Erkrankungen gegeben, die mit einem HD-Phänotyp in der Klinik vorstellig werden können. Zudem werden diagnostische Indikatoren aufgezeigt, die bei der Differenzialdiagnose helfen könnten.
A retrospective case series of suicide attempts leading to hospice admission
Authors: Fairman Nathan , Irwin Scott A. 
Published: July 2013

AbstractObjective:This investigation sought to systematically identify and characterize a cohort of patients treated in hospice for life-limiting injuries sustained in a suicide attempt that was not immediately lethal.Method:We developed a case series of all completed suicides in a large, community-based hospice, from 2004 through 2010. Clinical documentation and county medical examiner reports were used to identify those deaths that resulted from a suicide attempt made prior to hospice admission. Cases were characterized in terms of basic demographic variables, the temporal sequence of events in the transition from hospital care to hospice, the mechanism of injury and medical complications, the presence of mental illness, and family involvement in decision making.Results:Out of a total of 20,887 hospice deaths during the study period, 8 deaths resulted from an incomplete suicide attempt made prior to hospice admission. Subjects were nearly all male (6/8), and 46 years old on average; substantially younger than the general hospice population. Drug overdose was the most common method of suicide (5/8), and irreversible anoxic brain injury was the main medical complication. The majority of subjects (6/8) had evidence of serious mental illness. Most cases were complicated by estranged family relationships; however, family members were involved in end-of-life decision making for nearly all patients.Significance of results:Whereas a failed suicide attempt leading to hospice appears to be a relatively rare event, patients in this population appear unique in several regards. Further study may serve to better characterize this group and prepare hospice agencies and clinicians for caring for this unique population.
Coevolution with phages does not influence the evolution of bacterial mutation rates in soil
Authors: Gómez Pedro , Buckling Angus 
Published: July 2013

Abstract
Coevolution with phages drive the evolution of high bacterial mutation rates in vitro, but the relevance of this finding to natural populations is unclear. Here, we investigated how coevolution affects mutation rate evolution in soil, in the presence and absence of the rest of the natural microbial community. Although mutation rate on average increased threefold, neither coevolving phages nor the rest of natural community significantly affected mutation rates. Our results suggest that features of the soil over and above directly interacting organisms constrain the evolution of strong mutators, helping to explain their relatively low frequency compared with some laboratory and clinical settings.
Nuclear phosphatidylinositol-5-phosphate regulates ING2 stability at discrete chromatin targets in response to DNA damage
Authors: Bua Dennis J. , Martin Gloria Mas , Binda Olivier , Gozani Or 
Published: July 2013

AbstractING2 (inhibitor of growth family member 2) is a component of a chromatin-regulatory complex that represses gene expression and is implicated in cellular processes that promote tumor suppression. However, few direct genomic targets of ING2 have been identified and the mechanism(s) by which ING2 selectively regulates genes remains unknown. Here we provide evidence that direct association of ING2 with the nuclear phosphoinositide phosphatidylinositol-5-phosphate (PtdIns(5)P) regulates a subset of ING2 targets in response to DNA damage. At these target genes, the binding event between ING2 and PtdIns(5)P is required for ING2 promoter occupancy and ING2-associated gene repression. Moreover, depletion of PtdIns(5)P attenuates ING2-mediated regulation of these targets in the presence of DNA damage. Taken together, these findings support a model in which PtdIns(5)P functions as a sub-nuclear trafficking factor that stabilizes ING2 at discrete genomic sites.