bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conversion of a Dehalogenase into a Nitroreductase by Swapping its Flavin Cofactor with a 5‐Deazaflavin Analogue
Authors: Su Qi , Boucher Petrina A. , Rokita Steven E. 
Published: June 2017

AbstractNatural and engineered nitroreductases have rarely supported full reduction of nitroaromatics to their amine products, and more typically, transformations are limited to formation of the hydroxylamine intermediates. Efficient use of these enzymes also requires a regenerating system for NAD(P)H to avoid the costs associated with this natural reductant. Iodotyrosine deiodinase is a member of the same structural superfamily as many nitroreductases but does not directly consume reducing equivalents from NAD(P)H, nor demonstrate nitroreductase activity. However, exchange of its flavin cofactor with a 5‐deazaflavin analogue dramatically suppresses its native deiodinase activity and leads to significant nitroreductase activity that supports full reduction to an amine product in the presence of the convenient and inexpensive NaBH4.
Highly Syndiotactic or Isotactic Polyhydroxyalkanoates by Ligand‐Controlled Yttrium‐Catalyzed Stereoselective Ring‐Opening Polymerization of Functional Racemic β‐Lactones
Authors: Ligny Romain , Hänninen Mikko M. , Guillaume Sophie M. , Carpentier Jean‐François 
Published: June 2017

AbstractReported herein is the first stereoselective controlled ROP of a specific family of racemic functional β‐lactones, namely 4‐alkoxymethylene‐β‐propiolactones (BPLORs). This process is catalyzed by an yttrium complex stabilized by a nonchiral tetradentate amino alkoxy bisphenolate ligand {ONOOR′2}2−, which features both a good activity and a high degree of control over the molar masses of the resulting functional poly(3‐hydroxyalkanoate)s. A simple modification of the R′ substituents in ortho and para position on the ligand platform allows for a complete reversal from virtually pure syndioselectivity (Ps up to 0.91 with R′=cumyl) to very high isoselectivity (Pi up to 0.93 with R′=Cl), as supported by DFT insights. This is the first example of a highly isoselective ROP of a racemic chiral β‐lactone.
On the Reaction of Naphthalene Diimides with Fluoride Ions: Acid/Base versus Redox Reactions
Authors: Bélanger‐Chabot Guillaume , Ali Ahmed , Gabbaï François P. 
Published: June 2017

AbstractThe characterization of a naphthalene diimide (NDI) radical anion is presented. Its properties allow a reliable comparison point for other systems involving the NDI radical anion, such as systems claimed to perform the oxidation of the fluoride anion. In addition to reiterating the obvious thermodynamic objections to such an unlikely oxidation, we present several observations that show that the fluoride anion does not act as a one‐electron reducing agent toward the NDI investigated in this work.
Stabilizing Otherwise Unstable Anions with Halogen Bonding
Authors: Zhang Xinxing , Liu Gaoxiang , Ciborowski Sandra , Bowen Kit 
Published: June 2017

AbstractBoth hydrogen bonding (HB) and halogen bonding (XB) are essentially electrostatic interactions, but whereas hydrogen bonding has a well‐documented record of stabilizing unstable anions, little is known about halogen bonding's ability to do so. Herein, we present a combined anion photoelectron spectroscopic and density functional theory study of the halogen bond‐stabilization of the pyrazine (Pz) anion, an unstable anion in isolation due to its neutral counterpart having a negative electron affinity (EA). The halogen bond formed between the σ‐hole on bromobenzene (BrPh) and the lone pair(s) of Pz significantly lowers the energies of the Pz(BrPh)1− and Pz(BrPh)2− anions relative to the neutral molecule, resulting in the emergence of a positive EA for the neutral complexes. As seen through its charge distribution and electrostatic potential analyses, the negative charge on Pz− is diluted due to the XB. Thermodynamics reveals that the low temperature of the supersonic expansion plays a key role in forming these complexes.
A Red‐Light‐Activated Ruthenium‐Caged NAMPT Inhibitor Remains Phototoxic in Hypoxic Cancer Cells
Authors: Lameijer Lucien N. , Ernst Daniël , Hopkins Samantha L. , Meijer Michael S. , Askes Sven H. C. , Le Dévédec Sylvia E. , Bonnet Sylvestre 
Published: June 2017

AbstractWe describe two water‐soluble ruthenium complexes, [1]Cl2 and [2]Cl2, that photodissociate to release a cytotoxic nicotinamide phosphoribosyltransferase (NAMPT) inhibitor with a low dose (21 J cm−2) of red light in an oxygen‐independent manner. Using a specific NAMPT activity assay, up to an 18‐fold increase in inhibition potency was measured upon red‐light activation of [2]Cl2, while [1]Cl2 was thermally unstable. For the first time, the dark and red‐light‐induced cytotoxicity of these photocaged compounds could be tested under hypoxia (1 % O2). In skin (A431) and lung (A549) cancer cells, a 3‐ to 4‐fold increase in cytotoxicity was found upon red‐light irradiation for [2]Cl2, whether the cells were cultured and irradiated with 1 % or 21 % O2. These results demonstrate the potential of photoactivated chemotherapy for hypoxic cancer cells, in which classical photodynamic therapy, which relies on oxygen activation, is poorly efficient.
Diazirines as Potential Molecular Imaging Tags: Probing the Requirements for Efficient and Long‐Lived SABRE‐Induced Hyperpolarization
Authors: Shen Kun , Logan Angus W. J. , Colell Johannes F. P. , Bae Junu , Ortiz Gerardo X. , Theis Thomas , Warren Warren S. , Malcolmson Steven J. , Wang Qiu 
Published: June 2017

AbstractDiazirines are an attractive class of potential molecular tags for magnetic resonance imaging owing to their biocompatibility and ease of incorporation into a large variety of molecules. As recently reported, 15N2‐diazirine can be hyperpolarized by the SABRE‐SHEATH method, sustaining both singlet and magnetization states, thus offering a path to long‐lived polarization storage. Herein, we show the generality of this approach by illustrating that the diazirine tag alone is sufficient for achieving excellent signal enhancements with long‐lasting polarization. Our investigations reveal the critical role of Lewis basic additives, including water, on achieving SABRE‐promoted hyperpolarization. The application of this strategy to a 15N2‐diazirine‐containing choline derivative demonstrates the potential of 15N2‐diazirines as molecular imaging tags for biomedical applications.
Trifluoroacetic Anhydride Promoted Copper(I)‐Catalyzed Interrupted Click Reaction: From 1,2,3‐Triazoles to 3‐Trifluoromethyl‐Substituted 1,2,4‐Triazinones
Authors: Wu Wei , Wang Junwen , Wang Yukang , Huang Yangjie , Tan Yingfei , Weng Zhiqiang 
Published: June 2017

AbstractA copper(I)‐catalyzed interrupted click reaction in the presence of trifluoroacetic anhydride has been developed, wherein an N‐trifluoroacetyl group is used to accelerate the ring‐opening of the putative 5‐copper(I) triazolide intermediate. Under the optimized reaction conditions, a broad range of azides and alkynes were found to participate in this transformation, thus affording 3‐trifluoromethyl‐substituted 1,2,4‐triazinones in moderate to excellent yields. The reaction has proven to be compatible with a variety of electron‐withdrawing and electron–donating groups, halogens, and nitrogen‐ and sulfur‐containing heterocycles, as well as pharmaceutically relevant molecules.
People Wait Longer when the Alternative is Risky: The Relation Between Preferences in Risky and Inter‐temporal Choice
Authors: Luckman Ashley , Donkin Chris , Newell Ben R. 
Published: June 2017

AbstractIn two experiments, we demonstrate that despite indicating indifference when probed about risk or delay in isolation, when forced to explicitly trade‐off between the two, participants prefer delayed over risky rewards. This pattern of findings sets a boundary condition for any common utility‐based comparison process involving both risk and delay. Furthermore, this change from indifference‐in‐isolation to delay‐preference‐in‐a‐trade‐off strengthens as reward amount increases. Exploratory modeling results suggest that the shift in preference can be explained by allowing for different discount rates for delay‐only choices compared with when delay is in competition with risk. This explanation is better than one in which probability weighting is different between risk‐only choices and risks considered in the presence of a delay. Together, the empirical and modeling work lays a path for future investigations of why and when people's evaluation of the properties of risky and delayed choices vary as a function of the alternatives on offer. Copyright © 2017 John Wiley & Sons, Ltd.
How Does Explicit Versus Implicit Risk Information Influence Adolescent Risk‐Taking Engagement?
Authors: Osmont Anaïs , Moutier Sylvain , Simon Grégory , Bouhours Lison , Houdé Olivier , Cassotti Mathieu 
Published: June 2017

AbstractAdolescents have been shown to be more likely to engage in risky behaviors in daily life. Many studies have indicated that adolescents could make advantageous choices when they receive explicit information but could fail to choose advantageously when they are not informed about risks. The current study aimed to examine the influence of explicit risk information (i.e., when risk information is directly available) versus implicit risk information (i.e., when risk information has to be learned from feedback) on risk‐taking engagement, in order to clarify whether the enhanced risk‐taking observed in decision making under ambiguity in adolescents results from either a greater exploration of ambiguous situations (i.e., a higher ambiguity tolerance) or a specific difficulty associated with learning based on previous choices' outcomes. Adolescents and young adults completed a new adaptation of the Balloon Analogue Risk Task. They were required to accumulate as many points as possible by inflating balloons associated with variable break points and avoiding explosions. This adaptation involved a manipulation of the information level with two conditions, an “informed” condition and a “noninformed” condition, in which the participants had to learn the matching of colors with balloons' resistances based on feedback. The results demonstrated that providing explicit risk information allows adolescents to be as efficient as adults at the end of the game. In contrast, adolescents failed to adjust risk‐taking to the balloon resistance in the noninformed condition. These findings critically suggest that this failure reflects a specific impairment of feedback‐based learning ability but not a global excess of risk‐taking during adolescence. Copyright © 2017 John Wiley & Sons, Ltd.
Simple measures to prevent a massive upper gastrointestinal bleed
Authors: Bansal Raghav , Vyas Neil , Companioni Rafael Antonio Ching , Rajnish Ishita , Salehi Ilnaz 
Published: June 2017

Key Clinical MessageNasogastric (NG) tube is frequently used in clinical practice for a variety of indications; however, NG tubes are not without risks, and there are a multitude of gastrointestinal complications that are associated with their use. Simple precautions can help prevent these NG tube‐related injuries.
Cobalt Phosphonates as Precatalysts for Water Oxidation: Role of Pore Size in Catalysis
Authors: Saha Jony , Chowdhury Debarati Roy , Jash Priyajit , Paul Amit 
Published: June 2017

AbstractWe report a simple approach for the synthesis of cobalt phosphonate (CoOP) nanocages with two distinct types of pore diameters by utilizing a novel tetra‐constituent assembly of CoCl2⋅6 H2O, nitrilotris(methylene)triphosphonic acid (NMPA), F127 surfactant, and polyvinyl alcohol (PVA, co‐surfactant). Transmission electron microscopy images revealed the formation of large nanocages in spheres (pore diameter: 20–60 nm) and the existence of narrow micro/mesopores (pore diameter: 1.5–5 nm) on their walls. Brunauer–Emmett–Teller adsorption/desorption experiments led to the observation of dual porosity and indicated that the contribution of micro/mesopores increased gradually with increasing concentration of PVA during synthesis from CoOP‐0 to CoOP‐15 (where the number gives the wt % of PVA used in CoOP synthesis). These materials acted as precatalysts for heterogeneous water oxidation at pH 13.9 (1 m KOH) and electrochemical studies revealed that the reactivity improved remarkably with increasing contribution of narrow micro/mesopores. Among these catalysts, the best catalyst (CoOP‐15) exhibited an overpotential of 380 mV and turnover frequency of 1.6×10−2 s−1. The improvement of reactivity was due to significant enhancement of electrochemically accessible surface area with increasing contribution of narrow micro/mesopores, which facilitated contact between the catalyst and water molecules by improving mass transport inside the nanomaterials. Hence, this study suggests narrow micro/mesopores are beneficial towards enhancement of water oxidation catalysis.
Unearthing [3‐(Dimethylamino)propyl]aluminium(III) Complexes as Novel Atomic Layer Deposition (ALD) Precursors for Al2O3: Synthesis, Characterization and ALD Process Development
Authors: Mai Lukas , Gebhard Maximilian , de los Arcos Teresa , Giner Ignacio , Mitschker Felix , Winter Manuela , Parala Harish , Awakowicz Peter , Grundmeier Guido , Devi Anjana 
Published: June 2017

AbstractIdentification and synthesis of intramolecularly donor‐stabilized aluminium(III) complexes, which contain a 3‐(dimethylamino)propyl (DMP) ligand, as novel atomic layer deposition (ALD) precursors has enabled the development of new and promising ALD processes for Al2O3 thin films at low temperatures. Key for this promising outcome is the nature of the ligand combination that leads to heteroleptic Al complexes encompassing optimal volatility, thermal stability and reactivity. The first ever example of the application of this family of Al precursors for ALD is reported here. The process shows typical ALD like growth characteristics yielding homogeneous, smooth and high purity Al2O3 thin films that are comparable to Al2O3 layers grown by well‐established, but highly pyrophoric, trimethylaluminium (TMA)‐based ALD processes. This is a significant development based on the fact that these compounds are non‐pyrophoric in nature and therefore should be considered as an alternative to the industrial TMA‐based Al2O3 ALD process used in many technological fields of application.
α‐Unsubstituted Pyrroles by NHC‐Catalyzed Three‐Component Coupling: Direct Synthesis of a Versatile Atorvastatin Derivative
Authors: Fleige Mirco , Glorius Frank 
Published: June 2017

AbstractA practical one‐pot cascade reaction protocol provides direct access to valuable 1,2,4‐trisubstituted pyrroles. The process involves an N‐heterocyclic carbene (NHC)‐catalyzed Stetter‐type hydroformylation using glycolaldehyde dimer as a novel C1 building‐block, followed by a Paal‐Knorr condensation with primary amines. The reaction makes use of simple and commercially available starting‐materials and catalyst, an important feature regarding applicability and utility. Low catalyst loading under mild reaction conditions afforded a variety of 1,2,4‐substituted pyrroles in a transition‐metal‐free reaction with high step economy and good yields. This methodology is applied in the synthesis of a versatile Atorvastatin precursor, in which a variety of modifications at the pyrrole core structure are possible.
Understanding the relationship between the Centers for Medicare and Medicaid Services' Hospital Compare star rating, surgical case volume, and short‐term outcomes after major cancer surgery
Authors: Kaye Deborah R. , Norton Edward C. , Ellimoottil Chad , Ye Zaojun , Dupree James M. , Herrel Lindsey A. , Miller David C. 
Published: June 2017

BACKGROUNDBoth the Centers for Medicare and Medicaid Services' (CMS) Hospital Compare star rating and surgical case volume have been publicized as metrics that can help patients to identify high‐quality hospitals for complex care such as cancer surgery. The current study evaluates the relationship between the CMS' star rating, surgical volume, and short‐term outcomes after major cancer surgery.METHODSNational Medicare data were used to evaluate the relationship between hospital star ratings and cancer surgery volume quintiles. Then, multilevel logistic regression models were fit to examine the association between cancer surgery outcomes and both star rankings and surgical volumes. Lastly, a graphical approach was used to compare how well star ratings and surgical volume predicted cancer surgery outcomes.RESULTSThis study identified 365,752 patients undergoing major cancer surgery for 1 of 9 cancer types at 2,550 hospitals. Star rating was not associated with surgical volume (P < .001). However, both the star rating and surgical volume were correlated with 4 short‐term cancer surgery outcomes (mortality, complication rate, readmissions, and prolonged length of stay). The adjusted predicted probabilities for 5‐ and 1‐star hospitals were 2.3% and 4.5% for mortality, 39% and 48% for complications, 10% and 15% for readmissions, and 8% and 16% for a prolonged length of stay, respectively. The adjusted predicted probabilities for hospitals with the highest and lowest quintile cancer surgery volumes were 2.7% and 5.8% for mortality, 41% and 55% for complications, 12.2% and 11.6% for readmissions, and 9.4% and 13% for a prolonged length of stay, respectively. Furthermore, surgical volume and the star rating were similarly associated with mortality and complications, whereas the star rating was more highly associated with readmissions and prolonged length of stay.CONCLUSIONSIn the absence of other information, these findings suggest that the star rating may be useful to patients when they are selecting a hospital for major cancer surgery. However, more research is needed before these ratings can supplant surgical volume as a measure of surgical quality. Cancer 2017;123:4259–4267. © 2017 American Cancer Society.
Ferromagnetism and Half‐Metallicity in Atomically Thin Holey Nitrogenated Graphene Based Systems
Authors: Choudhuri Indrani , Pathak Biswarup 
Published: June 2017

AbstractMetal‐free half‐metallicity has been the subject of immense research focus in the field of spintronic devices. By using density functional theoretical (DFT) calculations, atomically thin holey nitrogenated graphene (C2N) based systems are studied for possible spintronic applications. Ferromagnetism is observed in all the C‐doped holey nitrogenated graphene. Interestingly, the holey nitrogenated graphene (C2N) based system shows strong half‐metallicity with a Curie temperature of approximately 297 K when a particular C‐doping concentration is reached. It shows a strong half‐metallicity compared with any metal‐free systems studied to date. Thus, such carbon nitride based systems can be used for a 100 % spin polarized current. Furthermore, such C‐doped systems show excellent dynamical, thermal, and mechanical properties. Thus, we predict a metal‐free planar ferromagnetic half‐metallic holey nitrogenated graphene based system for room‐temperature spintronic devices.
Antigen presenting cell‐targeted proinsulin expression converts insulin‐specific CD8+ T‐cell priming to tolerance in autoimmune‐prone NOD mice
Authors: Reeves Peta L. S. , Rudraraju Rajeev , Wong F. Susan , Hamilton‐Williams Emma E. , Steptoe Raymond J. 
Published: June 2017

AbstractType 1 diabetes (T1D) results from autoimmune destruction of insulin‐producing pancreatic β cells. Therapies need to incorporate strategies to overcome the genetic defects that impair induction or maintenance of peripheral T‐cell tolerance and contribute to disease development. We tested whether the enforced expression of an islet autoantigen in antigen‐presenting cells (APC) counteracted peripheral T‐cell tolerance defects in autoimmune‐prone NOD mice. We observed that insulin‐specific CD8+ T cells transferred to mice in which proinsulin was transgenically expressed in APCs underwent several rounds of division and the majority were deleted. Residual insulin‐specific CD8+ T cells were rendered unresponsive and this was associated with TCR downregulation, loss of tetramer binding and expression of a range of co‐inhibitory molecules. Notably, accumulation and effector differentiation of insulin‐specific CD8+ T cells in pancreatic lymph nodes was prominent in non‐transgenic recipients but blocked by transgenic proinsulin expression. This shift from T‐cell priming to T‐cell tolerance exemplifies the tolerogenic capacity of autoantigen expression by APC and the capacity to overcome genetic tolerance defects.
Capillary electrophoresis and nanomaterials – Part I: Capillary electrophoresis of nanomaterials
Authors: Adam Vojtech , Vaculovicova Marketa 
Published: June 2017

AbstractNanomaterials are in analytical science used for a broad range of purposes, covering the area of sample pretreatment as well as separation, detection, and identification of target molecules. This part of the review covers capillary electrophoresis (CE) of nanomaterials and focuses on the application of CE as a method for characterization used during nanomaterial synthesis and modification as well as the monitoring of their properties and interactions with other molecules. The heterogeneity of the nanomaterial family is extremely large. Depending on different definitions of the term Nanomaterial/Nanoparticle, the group may cover metal and polymeric nanoparticles, carbon nanomaterials, liposomes and even dendrimers. Moreover, these nanomaterials are usually subjected to some kind of surface modification or functionalization, which broadens the diversity even more. Not only for purposes of verification of nanomaterial synthesis and batch‐to‐batch quality check, but also for determination the polydispersity and for functionality characterization on the nanoparticle surface, has CE offered very beneficial capabilities. Finally, the monitoring of interactions between nanomaterials and other (bio)molecules is easily performed by some kind of capillary electromigration technique.
Evaluating morphological estimates of the aerodynamic roughness of debris covered glacier ice
Authors: Quincey Duncan , Smith Mark , Rounce David , Ross Andrew , King Owen , Watson Cameron 
Published: June 2017

AbstractAerodynamic roughness length (z0), the height above the ground surface at which the extrapolated horizontal wind velocity profile drops to zero, is one of the most poorly parameterised elements of the glacier surface energy balance equation. Microtopographic methods for estimating z0 have become prominent in the literature in recent years, but are rarely validated against independent measures and are yet to be comprehensively analysed for scale or data resolution dependency. Here, we present the results of a field investigation conducted on the debris covered Khumbu Glacier during the post‐monsoon season of 2015. We focus on two sites. The first is characterised by gravels and cobbles supported by a fine sandy matrix. The second comprises cobbles and boulders separated by voids. Vertical profiles of wind speed recorded by a tower comprising five cup anemometers and deployed over both sites enable us to derive measurements of aerodynamic roughness that reflect their observed surface characteristics (0.0184 m and 0.0243 m, respectively). At the second site, z0 also varied through time following snowfall (0.0055 m) and during its subsequent melt (0.0129 m), showing the importance of fine resolution topography for near‐surface airflow. To compare the wind profile data with microtopographic methods, we conducted structure from motion multi‐view stereo (SfM‐MVS) surveys across each patch and calculated z0 using three previously published approaches. The fully three‐dimensional cloud‐based approach is shown to be most stable across different scales and these z0 values are most correct in relative order when compared with the wind tower data. Popular profile‐based methods perform less well providing highly variable values across different scales and when using data of differing resolution. These findings hold relevance for all studies using microtopographic methods to estimate aerodynamic roughness lengths, including those in non‐glacial settings. Copyright © 2017 John Wiley & Sons, Ltd.