bluuebunny/crossref_metadata_2025_split huggingface dataset:
The stone formation in the Memotherm urethral stent implantation area: Is it a rare complication?
Authors: Karaköse Ayhan , Atesci Yusuf Ziya , Aydogdu Ozgu 
Published: March 2014

Recurrent urethral stricture is one of the biggest problems in urology. Urethral stents as an alternative treatment to traditional methods has been used since 1985 in the treatment of urethral strictures. The stone formation in the Memotherm urethral stent implantation area is a rare complication. We report the case of a 67-year-old man who presented a stone in the Memotherm urethral stent implantation area after 6 years from the urethral stent surgery.
Société de l’information et infobésité : perceptions et représentations croisées
Authors: Reibel Marie , Desrochers Nadine 
Published: March 2014

Cette étude qualitative de contenu vise à interroger les concepts de société de l’information et d’infobésité auprès d’un petit groupe d’étudiants par l’entremise d’un questionnaire en ligne. Des représentations artistiques de ces concepts ont été présentées aux répondants afin d’évaluer leurs perceptions. Les résultats obtenus mettent l’accent sur la valeur de l’information, une forte présence de la communauté et révèlent également un rapport au temps singulier. Les données ont été analysées à la lumière d’un cadre conceptuel comprenant quatre auteurs : Daniel Bell, Manuel Castells, Roland Barthes et Lev Manovich.
Adolescent HIV disclosure in Zambia: barriers, facilitators and outcomes
Authors: Mburu Gitau , Hodgson Ian , Kalibala Sam , Haamujompa Choolwe , Cataldo Fabian , Lowenthal Elizabeth D , Ross David 
Published: March 2014

IntroductionAs adolescents living with HIV gain autonomy over their self‐care and begin to engage in sexual relationships, their experiences of being informed about their HIV status and of telling others about their HIV status may affect their ability to cope with having the disease.MethodsIn 2010, we conducted a qualitative study among adolescents aged 10–19 living with HIV in Zambia, and with their parents and health care providers. Through interviews and focus group discussions, we explored the disclosure of HIV status to adolescents living with HIV; adolescents’ disclosure of their status to others; and the impact of both forms of disclosure on adolescents.ResultsOur study identified three main barriers to disclosure of HIV status: local norms that deter parents from communicating with their children about sexuality; fear of HIV stigma; and an underlying presumption that adolescents would not understand the consequences of a HIV diagnosis on their lives and relationships. With regard to adolescents’ disclosure of their HIV status to their sexual partners, our study identified fear of rejection as a common barrier. In rare cases, open family conversations about HIV helped adolescents come to terms with a HIV diagnosis. Findings indicated that disclosure had various outcomes at the individual and interpersonal levels. At the individual level, some adolescents described being anxious, depressed and blaming themselves after being told they had HIV. At the interpersonal level, disclosure created opportunities for adolescents to access adherence support and other forms of psychosocial support from family members and peers. At the same time, it occasionally strained adolescents’ sexual relationships, although it did not always lead to rejection.ConclusionsThere is a need for public health interventions that guide adolescents living with HIV, their parents and families through the disclosure process. Such interventions should help parents to assess and understand the evolving cognitive capacity and maturity of their adolescents in order to determine the appropriate time to inform them of their HIV‐positive status. Such interventions should also mitigate the risk of HIV stigma, as well as local norms that may prevent discussions of sexuality within families. Adolescents who have been informed of their HIV status should be provided with on‐going support to prevent disclosure from negatively affecting their psychological and sexual wellbeing. Further research is needed to explore the potential role of trusted family members in contributing to the disclosure process.
Evidence of deflected super‐Alfvénic electron jet in a reconnection region with weak guide field
Authors: Zhou Meng , Deng Xiaohua , Tang Rongxin , Pang Ye , Xu Xiaojun , Yuan Zhigang , Huang Shiyong 
Published: March 2014

AbstractRecent numerical simulations demonstrated that electron diffusion region develops into two‐scale structure, i.e., the inner electron diffusion region and the outer electron diffusion region. The outer diffusion region is manifested as super‐Alfvénic electron jet embedded in central current sheet. However, the electron jets are deflected from neutral sheet with a weak guide field. In this paper we present the in situ evidence of deflected super‐Alfvénic electron jet in a reconnection region with a weak guide field in the Earth's magnetotail. The electron‐scale jet was detected at about 37 ion inertial lengths from the X line. There was a strong electric field at the jet. The strong electric field at the jet was primarily balanced by Hall electric field, as the intense current was mainly carried by magnetized electrons. Another event in the magnetosheath also supports our conclusion that guide field deflects the electron jet away the neutral sheet.
Bayesian inversion for the filtered flow at the Earth's core‐mantle boundary
Authors: Baerenzung Julien , Holschneider Matthias , Lesur Vincent 
Published: March 2014

AbstractThe inverse problem of determining the flow at the Earth's core‐mantle boundary according to an outer core magnetic field and secular variation model has been investigated through a Bayesian formalism. To circumvent the issue arising from the truncated nature of the available fields, we combined two modeling methods. In the first step, we applied a filter on the magnetic field to isolate its large scales by reducing the energy contained in its small scales, we then derived the dynamical equation, referred as filtered frozen flux equation, describing the spatiotemporal evolution of the filtered part of the field. In the second step, we proposed a statistical parametrization of the filtered magnetic field in order to account for both its remaining unresolved scales and its large‐scale uncertainties. These two modeling techniques were then included in the Bayesian formulation of the inverse problem. To explore the complex posterior distribution of the velocity field resulting from this development, we numerically implemented an algorithm based on Markov chain Monte Carlo methods. After evaluating our approach on synthetic data and comparing it to previously introduced methods, we applied it to a magnetic field model derived from satellite data for the single epoch 2005.0. We could confirm the existence of specific features already observed in previous studies. In particular, we retrieved the planetary scale eccentric gyre characteristic of flow evaluated under the compressible quasi‐geostrophy assumption although this hypothesis was not considered in our study. In addition, through the sampling of the velocity field posterior distribution, we could evaluate the reliability, at any spatial location and at any scale, of the flow we calculated. The flow uncertainties we determined are nevertheless conditioned by the choice of the prior constraints we applied to the velocity field.
Cloud‐precipitation‐radiation‐dynamics interaction in global climate models: A snow and radiation interaction sensitivity experiment
Authors: Li J.‐L. F. , Lee W.‐L. , Waliser D. E. , David Neelin J. , Stachnik Justin P. , Lee Tong 
Published: March 2014

AbstractConventional global climate models (GCMs) often consider radiation interactions only with small‐particle/suspended cloud mass, ignoring large‐particle/falling and convective core cloud mass. We characterize the radiation and atmospheric circulation impacts of frozen precipitating hydrometeors (i.e., snow), using the National Center for Atmospheric Research coupled GCM, by conducting sensitivity experiments that turn off the radiation interaction with snow. The changes associated with the exclusion of precipitating hydrometeors exhibit a number differences consistent with biases in CMIP3 and CMIP5 (Coupled Model Intercomparison Project Phase 3 and Phase 5), including more outgoing longwave flux at the top of atmosphere and downward shortwave flux at the surface in the heavily precipitating regions. Neglecting the radiation interaction of snow increases the net radiative cooling near the cloud top with the resulting increased instability triggering more convection in the heavily precipitating regions of the tropics. In addition, the increased differential vertical heating leads to a weakening of the low‐level mean flow and an apparent low‐level eastward advection from the warm pool resulting in moisture convergence south of the Intertropical Convergence Zone and north of the South Pacific Convergence Zone (SPCZ). This westerly bias, with effective warm and moist air transport, might be a contributing factor in the model's northeastward overextension of the SPCZ and the concomitant changes in sea surface temperatures, upward motion, and precipitation. Broader dynamical impacts include a stronger local meridional overturning circulation over the middle and east Pacific and commensurate changes in low and upper level winds, large‐scale ascending motion, with a notable similarity to the systematic bias in this region in CMIP5 upper level zonal winds.
Polymer‐Supported Electron‐Rich Oxime Palladacycle as an Efficient Heterogeneous Catalyst for the Suzuki Coupling Reaction
Authors: Cho Hong‐Jun , Jung Sungwon , Kong Saerom , Park Sung‐Jun , Lee Sang‐Myung , Lee Yoon‐Sik 
Published: March 2014

AbstractVarious electron‐rich oxime palladacycle resins designed as heterogeneous catalysts were employed for the Suzuki coupling reaction of aryl halides with arylboronic acids. The electron‐richness of the oxime ligand was controlled by the substituted alkoxy groups. Evaluation based on the electronic effect of the catalysts revealed that the alkoxy‐substituted oxime palladacycle resins showed better catalytic activity than palladated Kaiser oxime resin in the Suzuki coupling reactions and that the catalytic activity of oxime palladacycle resins increased as the electron‐richness of oxime ligand increased. The most electron‐rich oxime palladacycle resin exhibited an excellent catalytic performance for the synthesis of both biaryl and heterobiaryl compounds, despite its heterogeneous system. As a practical application of the catalyst, a valsartan precursor was synthesized in high yield under mild conditions. The electron‐rich oxime resin could also be reused for up to 5 cycles while maintaining good catalytic activity in the Suzuki coupling reaction.magnified image
Adhesive Catalyst Immobilization of Palladium Nanoparticles on Cotton and Filter Paper: Applications to Reusable Catalysts for Sequential Catalytic Reactions
Authors: Nishikata Takashi , Tsutsumi Hironori , Gao Lei , Kojima Keisuke , Chikama Katsumi , Nagashima Hideo 
Published: March 2014

AbstractPalladium nanoparticles dispersed in ammonium salts of hyperbranched polystyrenes are adhesively immobilized on the surface of cotton or filter papers by simply heating with dicarboxylic acids or halide anions. The resulting Pd@cotton and Pd@filter paper behave as reusable catalysts; in particular, Pd@filter paper is useful as catalyst for application to sequential cross‐coupling and hydrogenation reactions to produce several different products with just one piece of the paper catalyst.magnified image
Sodium Nitrite‐Catalyzed Aerobic Oxidative Csp2Csp3 Coupling: Direct Construction of the 4‐Aryldihydroisoquinolinone Moiety
Authors: Su Bo , Deng Meng , Wang Qingmin 
Published: March 2014

AbstractA bioinspired approach for the construction of the 4‐aryldihydroisoquinolinone moiety via direct oxidative Csp2Csp3 coupling has been developed, which uses inexpensive sodium nitrite as catalyst and environmentally benign oxygen in the air as terminal oxidant.magnified image
New Palladium‐Catalyzed Domino Reaction with Intramolecular Ring Closure of an N‐(2‐Chloro‐3‐heteroaryl)arylamide: First Synthesis of Oxazolo[4,5‐b]pyrazines
Authors: Demmer Charles S. , Hansen Jacob C. , Kehler Jan , Bunch Lennart 
Published: March 2014

AbstractThe synthesis of novel planar heterocycles is at the heart of basic research as such scaffolds constitute key building blocks in important diverse areas of research: drug discovery, material sciences, and pesticides. The well‐known benzoxazole is often contained in drug candidates but tweaking its lipophilicity and target interaction points are often desired. In this respect, the oxazolo[4,5‐b]pyrazine is an attractive heterocyclic scaffold as it possesses increased water solubility as well as two additional hydrogen bonding acceptors. We here report a new Pd(II)‐catalyzed domino reaction comprising the first Pd(II)‐assisted intramolecular cyclization of an N‐(2‐chloro‐3‐heteroaryl)arylamide and validate its value by application to the first synthesis of 2‐substituted oxazolo[4,5‐b]pyrazines. We demonstrate that a bidentate phosphorus ligand as well as the presence of an aromatic nitrogen atom is required for the domino reaction to proceed. The robustness of the methodology is confirmed by the synthesis of 23 2‐substituted oxazolo[4,5‐b]pyrazine analogues in good‐to‐high yields and containing both electron‐withdrawing as well as electron‐donating substituents on the reacting arylamide.magnified image
Nickel‐Catalyzed Regio‐ and Stereoselective Reductive Coupling of Oxa‐ and Azabicyclic Alkenes with Enones and Electron‐Rich Alkynes
Authors: Mannathan Subramaniyan , Cheng Chien‐Hong 
Published: March 2014

AbstractA nickel‐catalyzed regio‐ and stereoselective reductive coupling of oxa‐ and azabicyclic alkenes with activated alkenes and electron‐rich alkynes is described. Thus, 7‐oxabenzonorbornadienes underwent reductive coupling with various vinyl ketones such as ethyl, methyl, propyl and α‐methyl‐substituted vinyl ketones, in the presence of a nickel(II) iodide (NiI2), zinc (Zn), and water catalyst system in acetonitrile at 50 °C for 14 h to afford 2‐alkylnaphthalenes in good to excellent yields. Under similar reaction conditions, 7‐azabenzonorbornadiene derivatives provided cis‐2‐alkyl‐1,2‐dihydronaphthalene derivatives in high yields. On the other hand, the nickel(II) iodide, tris(4‐fluorophenyl)phoshine [P(4‐FC6H4)3] and zinc catalyst system successfully catalyzed the reductive coupling reaction of electron‐rich alkynes, with 7‐aza‐ and 7‐oxabenzonorbornadienes to give cis‐2‐alkenyl‐1,2‐dihydronaphthalene derivatives in good to excellent yields. In the reaction, a mild reducing agent (zinc) and simple hydrogen source (water) were used.magnified image
Reversible P(III)/P(V) Redox: Catalytic Aza‐Wittig Reaction for the Synthesis of 4(3H)‐Quinazolinones and the Natural Product Vasicinone
Authors: Wang Long , Wang Ying , Chen Min , Ding Ming‐Wu 
Published: March 2014

AbstractThe catalytic aza‐Wittig reaction based on a phosphine/phosphine oxide catalytic cycle is reported. The by‐product triphenylphosphine oxide (Ph3PO) was reducedin situto triphenylphosphine (Ph3P) with good chemselectivity so that the aza‐Wittig reaction can be accomplished by using merely a catalytic amount of triphenylphosphine. The reaction has been demonstrated in an efficient synthesis of 4(3H)‐quinazolinones and the natural product (S)‐vasicinone in high yields, by using a catalytic amount of triphenylphosphine (5%) and the tetramethyldisiloxane/titanium tetraisopropoxide [TMDS/Ti(O‐i‐Pr)4] reductant system (81–95% yields and >99%ee).magnified image
Does affective organizational commitment and experience of meaning at work predict risk of disability pensioning? An analysis of register‐based outcomes using pooled data on 40,554 observations in four occupational groups
Authors: Clausen Thomas , Burr Hermann , Borg Vilhelm 
Published: March 2014

AbstractBackgroundThe aim of this study is to investigate whether experience of meaning at work (MAW) and affective organizational commitment (AOC) predict risk of disability pensioning in four occupational groups.MethodsSurvey data from 40,554 individuals were fitted to a national register (DREAM) containing information on payments of disability pension. Using multi‐adjusted Cox‐regression, observations were followed in the DREAM‐register to assess risk of disability pensioning.ResultsLow levels of MAW significantly increased risk of disability pensioning during follow‐up referencing high levels of MAW. Respondents with medium levels of AOC had a significantly reduced risk of disability pensioning, when compared to respondents with high levels of AOC. Furthermore, results indicate an interaction effect between AOC and MAW in predicting risk of disability pension.ConclusionsAOC and MAW are significantly associated with risk of disability pensioning. Promoting MAW and managing AOC in contemporary workplaces may contribute towards reducing risk of disability pensioning. Am. J. Ind. Med. 57:709–717, 2014. © 2014 Wiley Periodicals, Inc.
Copper(I) Iodide Catalyzed Aerobic Oxidative CN and CS bond formations through CH Activation: Synthesis of Functionalized Imidazo[1,2‐a]pyridines
Authors: Mohan Darapaneni Chandra , Rao Sadu Nageswara , Ravi Chitrakar , Adimurthy Subbarayappa 
Published: March 2014

AbstractCopper(I) iodide catalyzed oxidative synthesis of imidazo[1,2‐a]pyridines through CH activation of methyl ketones in water is reported. One‐pot, three‐component coupling reactions for the synthesis of sulfenylimidazo [1,2‐a]pyridines have also been developed from readily available methyl ketones, amino pyridines, and diphenyl disulphide.
Repairing the Thiol‐Ene Coupling Reaction
Authors: Povie Guillaume , Tran Anh‐Tuan , Bonnaffé David , Habegger Jacqueline , Hu Zhaoyu , Le Narvor Christine , Renaud Philippe 
Published: March 2014

AbstractThiol‐ene coupling (TEC) reactions emerged as one of the most useful processes for coupling different molecular units under reaction mild conditions. However, TEC reactions involving weak CH bonds (allylic and benzylic fragments) are difficult to run and often low yielding. Mechanistic studies demonstrate that hydrogen‐atom transfer processes at allylic and benzylic positions are responsible for the lack of efficiency of the radical‐chain process. These competing reactions cannot be prevented, but reported herein is a method to repair the chain process by running the reaction in the presence of triethylborane and catechol. Under these reaction conditions, a unique repair mechanism leads to an efficient chain reaction, which is demonstrated with a broad range of anomeric O‐allyl sugar derivatives including mono‐, di‐, and tetrasaccharides bearing various functionalities and protecting groups.
Genetically Encoding Photoswitchable Click Amino Acids in Escherichia coli and Mammalian Cells
Authors: Hoppmann Christian , Lacey Vanessa K. , Louie Gordon V. , Wei Jing , Noel Joseph P. , Wang Lei 
Published: March 2014

AbstractThe ability to reversibly control protein structure and function with light would offer high spatiotemporal resolution for investigating biological processes. To confer photoresponsiveness on general proteins, we genetically incorporated a set of photoswitchable click amino acids (PSCaas), which contain both a reversible photoswitch and an additional click functional group for further modifications. Orthogonal tRNA‐synthetases were evolved to genetically encode PSCaas bearing azobenzene with an alkene, keto, or benzyl chloride group in E. coli and in mammalian cells. After incorporation into calmodulin, the benzyl chloride PSCaa spontaneously generated a covalent protein bridge by reacting with a nearby cysteine residue through proximity‐enabled bioreactivity. The resultant azobenzene bridge isomerized in response to light, thereby changing the conformation of calmodulin. These genetically encodable PSCaas will prove valuable for engineering photoswitchable bridges into proteins for reversible optogenetic regulation.
The Isolation and Characterization of a Rhodacycle Intermediate Implicated in Metal‐Catalyzed Reactions of Alkylidenecyclopropanes
Authors: Inglesby Phillip A. , Bacsa John , Negru Daniela E. , Evans P. Andrew 
Published: March 2014

AbstractThe isolation and characterization of a rhodacycle intermediate implicated in rhodium‐catalyzed reactions of alkylidenecyclopropanes (ACPs) is described. The structure of the metallacycle was unambiguously determined by X‐ray crystallography and is catalytically competent in the rhodium‐catalyzed carbocyclization and ene‐cycloisomerization reactions of ACPs. This work represents a rare example of the isolation of a metallacycle in a metal‐catalyzed higher‐order carbocyclization reaction and thereby provides important insight into the ligand requirements for the insertion of π‐components. Furthermore, it serves as a convenient synthon for the development of challenging higher‐order carbocyclization reactions, as exemplified by the reaction with an activated allene.
Self‐assembled Dynamic 3D Fingerprints in Liquid‐Crystal Coatings Towards Controllable Friction and Adhesion
Authors: Liu Danqing , Broer Dirk J. 
Published: March 2014

AbstractChiral‐nematic polymer network coatings form a “fingerprint” texture through self‐assembly. For this purpose the molecular helix of the coating is oriented parallel to the substrate. The coating has a flat surface but when actuated by light in the presence of a copolymerized azobenzene compound, 3D fingerprint structures appear in the coating. The helix forms protrusions at the positions where the molecules are aligned parallel to the surface and withdraws at the positions where the orientation is perpendicular. This process proceeds rapidly and is reversible, that is, the fingerprint‐shaped protrusions disappear when the light is switched off. The texture in the on‐state resembles that of a human fingerprint and is used to manipulate the gripping friction of a robotic finger. The friction coefficient drops by a factor of four to five when the fingerprint switched on because of reduced surface contacts.
Oxidative Cross‐Coupling of Allenyl Ketones and Organoboronic Acids: Expeditious Synthesis of Highly Substituted Furans
Authors: Xia Ying , Xia Yamu , Ge Rui , Liu Zhen , Xiao Qing , Zhang Yan , Wang Jianbo 
Published: March 2014

AbstractAllenyl ketones are employed as coupling partners in palladium‐catalyzed oxidative cross‐coupling reactions with organoboronic acids. This reaction constitutes an efficient methodology for the synthesis of highly substituted furan derivatives. Palladium‐carbene migratory insertion is proposed as the key step in this transformation.
Aerobic Damage to [FeFe]‐Hydrogenases: Activation Barriers for the Chemical Attachment of O2
Authors: Kubas Adam , De Sancho David , Best Robert B. , Blumberger Jochen 
Published: March 2014

Abstract[FeFe]‐hydrogenases are the best natural hydrogen‐producing enzymes but their biotechnological exploitation is hampered by their extreme oxygen sensitivity. The free energy profile for the chemical attachment of O2 to the enzyme active site was investigated by using a range‐separated density functional re‐parametrized to reproduce high‐level ab initio data. An activation free‐energy barrier of 13 kcal mol−1 was obtained for chemical bond formation between the di‐iron active site and O2, a value in good agreement with experimental inactivation rates. The oxygen binding can be viewed as an inner‐sphere electron‐transfer process that is strongly influenced by Coulombic interactions with the proximal cubane cluster and the protein environment. The implications of these results for future mutation studies with the aim of increasing the oxygen tolerance of this enzyme are discussed.