bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of the summertime surface energy budget of Larsen C Ice Shelf (Antarctica) as represented in three high‐resolution atmospheric models
Authors: King J. C. , Gadian A. , Kirchgaessner A. , Kuipers Munneke P. , Lachlan‐Cope T. A. , Orr A. , Reijmer C. , van den Broeke M. R. , van Wessem J. M. , Weeks M. 
Published: February 2015

AbstractWe compare measurements of the turbulent and radiative surface energy fluxes from an automatic weather station (AWS) on Larsen C Ice Shelf, Antarctica with corresponding fluxes from three high‐resolution atmospheric models over a 1 month period during austral summer. All three models produce a reasonable simulation of the (relatively small) turbulent energy fluxes at the AWS site. However, biases in the modeled radiative fluxes, which dominate the surface energy budget, are significant. There is a significant positive bias in net shortwave radiation in all three models, together with a corresponding negative bias in net longwave radiation. In two of the models, the longwave bias only partially offsets the positive shortwave bias, leading to an excessive amount of energy available for heating and melting the surface, while, in the third, the negative longwave bias exceeds the positive shortwave bias, leading to a deficiency in calculated surface melt. Biases in shortwave and longwave radiation are anticorrelated, suggesting that they both result from the models simulating too little cloud (or clouds that are too optically thin). We conclude that, while these models may be able to provide some useful information on surface energy fluxes, absolute values of modeled melt rate are significantly biased and should be used with caution. Efforts to improve model simulation of melt should initially focus on the radiative fluxes and, in particular, on the simulation of the clouds that control these fluxes.
Simulating vegetation controls on hurricane‐induced shallow landslides with a distributed ecohydrological model
Authors: Hwang Taehee , Band Lawrence E. , Hales T. C. , Miniat Chelcy F. , Vose James M. , Bolstad Paul V. , Miles Brian , Price Katie 
Published: February 2015

AbstractThe spatial distribution of shallow landslides in steep forested mountains is strongly controlled by aboveground and belowground biomass, including the distribution of root cohesion. While remote sensing of aboveground canopy properties is relatively advanced, estimating the spatial distribution of root cohesion at the forest landscape scale remains challenging. We utilize canopy height information estimated using lidar (light detecting and ranging) technology as a tool to produce a spatially distributed root cohesion model for landslide hazard prediction. We characterize spatial patterns of total belowground biomass based on the empirically derived allometric relationship developed from soil pit measurements in the Coweeta Hydrologic Laboratory, North Carolina. The vertical distribution of roots and tensile strength were sampled at soil pits allowing us to directly relate canopy height to root cohesion and use this model within a distributed ecohydrological modeling framework, providing transient estimates of runoff, subsurface flow, soil moisture, and pore pressures. We tested our model in mountainous southern Appalachian catchments that experienced a number of landslides during the 2004 hurricane season. Slope stability estimates under the assumption of spatially uniform root cohesion significantly underpredicted both the total number of landslides and the number of “false positives,” unfailed areas of the landscape that were predicted to fail. When we incorporate spatially distributed root cohesion, the accuracy of the slope stability forecast improves dramatically. With the growing availability of lidar data that can be used to infer belowground information, these methods may provide a wider utility for improving landslide hazard prediction and forecasting.
Asymmetric Hydroalkoxylation of Non‐Activated Alkenes: Titanium‐Catalyzed Cycloisomerization of Allylphenols at High Temperatures
Authors: Schlüter Johannes , Blazejak Max , Boeck Florian , Hintermann Lukas 
Published: February 2015

AbstractThe asymmetric catalytic addition of alcohols (phenols) to non‐activated alkenes has been realized through the cycloisomerization of 2‐allylphenols to 2‐methyl‐2,3‐dihydrobenzofurans (2‐methylcoumarans). The reaction was catalyzed by a chiral titanium–carboxylate complex at uncommonly high temperatures for asymmetric catalytic reactions. The catalyst was generated by mixing titanium isopropoxide, the chiral ligand (aS)‐1‐(2‐methoxy‐1‐naphthyl)‐2‐naphthoic acid or its derivatives, and a co‐catalytic amount of water in a ratio of 1:1:1 (5 mol % each). This homogeneous thermal catalysis (HOT‐CAT) gave various (S)‐2‐methylcoumarans with yields of up to 90 % and in up to 85 % ee at 240 °C, and in 87 % ee at 220 °C.
Visible‐Light‐Promoted Iminyl‐Radical Formation from Acyl Oximes: A Unified Approach to Pyridines, Quinolines, and Phenanthridines
Authors: Jiang Heng , An Xiaode , Tong Kun , Zheng Tianyi , Zhang Yan , Yu Shouyun 
Published: February 2015

AbstractA unified strategy involving visible‐light‐induced iminyl‐radical formation has been established for the construction of pyridines, quinolines, and phenanthridines from acyl oximes. With fac‐[Ir(ppy)3] as a photoredox catalyst, the acyl oximes were converted by 1 e− reduction into iminyl radical intermediates, which then underwent intramolecular homolytic aromatic substitution (HAS) to give the N‐containing arenes. These reactions proceeded with a broad range of substrates at room temperature in high yield. This strategy of visible‐light‐induced iminyl‐radical formation was successfully applied to a five‐step concise synthesis of benzo[c]phenanthridine alkaloids.
Observation of Diastereotopic Signals in 15N NMR Spectroscopy
Authors: Alkorta Ibon , Dardonville Christophe , Elguero José 
Published: February 2015

AbstractThe first example in the literature of a compound showing anisochronous 15N atoms resulting from diastereotopicity is described. Racemic 1,3‐dimethyl‐2‐phenyloctahydro‐1H‐benzimidazole was prepared and studied by 1H, 13C and 15N NMR spectroscopy. If convenient conditions were used (monitored by theoretical calculations of 2JN‐H spin–spin coupling constants), two 15N NMR signals were observed and corresponded to the diastereotopic atoms. GIAO/density‐functional calculations of chemical shifts were not only in good agreement with the experimental values but also served as prediction tools. This study suggests that 15N NMR spectroscopy could be used to probe chirality.
Active Sites and Mechanisms for Direct Oxidation of Benzene to Phenol over Carbon Catalysts
Authors: Wen Guodong , Wu Shuchang , Li Bo , Dai Chunli , Su Dang Sheng 
Published: February 2015

AbstractThe direct oxidation of benzene to phenol with H2O2 as the oxidizer, which is regarded as an environmentally friendly process, can be efficiently catalyzed by carbon catalysts. However, the detailed roles of carbon catalysts, especially what is the active site, are still a topic of debate controversy. Herein, we present a fundamental consideration of possible mechanisms for this oxidation reaction by using small molecular model catalysts, Raman spectra, static secondary ion mass spectroscopy (SIMS), DFT calculations, quasi in situ ATR‐IR and UV spectra. Our study indicates that the defects, being favorable for the formation of active oxygen species, are the active sites for this oxidation reaction. Furthermore, one type of active defect, namely the armchair configuration defect was successfully identified.
Identification of Structure–Activity Relationships from Screening a Structurally Compact DNA‐Encoded Chemical Library
Authors: Franzini Raphael M. , Ekblad Torun , Zhong Nan , Wichert Moreno , Decurtins Willy , Nauer Angela , Zimmermann Mauro , Samain Florent , Scheuermann Jörg , Brown Peter J. , Hall Jonathan , Gräslund Susanne , Schüler Herwig , Neri Dario 
Published: February 2015

AbstractMethods for the rapid and inexpensive discovery of hit compounds are essential for pharmaceutical research and DNA‐encoded chemical libraries represent promising tools for this purpose. We here report on the design and synthesis of DAL‐100K, a DNA‐encoded chemical library containing 103 200 structurally compact compounds. Affinity screening experiments and DNA‐sequencing analysis provided ligands with nanomolar affinities to several proteins, including prostate‐specific membrane antigen and tankyrase 1. Correlations of sequence counts with binding affinities and potencies of enzyme inhibition were observed and enabled the identification of structural features critical for activity. These results indicate that libraries of this type represent a useful source of small‐molecule binders for target proteins of pharmaceutical interest and information on structural features important for binding.
NiS Hollow Spheres for High‐Performance Supercapacitors and Non‐Enzymatic Glucose Sensors
Authors: Wei Chengzhen , Cheng Cheng , Zhao Junhong , Wang Yan , Cheng Yanyan , Xu Yazhou , Du Weimin , Pang Huan 
Published: February 2015

Abstractα‐NiS and β‐NiS hollow spheres were successfully synthesized via the Kirkendall effect under different hydrothermal conditions. The obtained α‐NiS and β‐NiS hollow spheres were evaluated as electrode materials for supercapacitors. Importantly, the α‐NiS hollow sphere electrode has a large specific capacitance (562.3 F g−1 at 0.60 A g−1) and good cycling property (maintaining about 97.5 % at 2.4 A g−1 after 1000 cycles). Furthermore, the as‐prepared α‐NiS and β‐NiS hollow spheres were successfully applied to construct electrochemical glucose sensors. Especially, the α‐NiS hollow spheres exhibit a good sensitivity (155 μA mM−1 cm−2), low detection limit (0.125 μM), and a wide linear range.
Paravalvular leak closure after transcatheter aortic valve replacement: Technical challenges and clinical utility
Authors: Feldman Ted 
Published: February 2015

Key Points

Post TAVR PVL closure with low profile vascular plugs is feasible, even for the relatively longer frame of the CoreValve device.
Device closure for PVL may be successful even after post‐dilatation and valve‐in‐valve have failed.
The low profile of the AVP4, which can pass through 4‐5F diagnostic catheters, makes this approach practical.
© 2014 Wiley Periodicals, Inc.
Bifunctional Cyclam‐Based Ligands with Phosphorus Acid Pendant Moieties for Radiocopper Separation: Thermodynamic and Kinetic Studies
Authors: Paúrová Monika , Havlíčková Jana , Pospíšilová Aneta , Vetrík Miroslav , Císařová Ivana , Stephan Holger , Pietzsch Hans‐Jürgen , Hrubý Martin , Hermann Petr , Kotek Jan 
Published: February 2015

AbstractTwo macrocyclic ligands based on cyclam with trans‐disposed N‐methyl and N‐(4‐aminobenzyl) substituents as well as two methylphosphinic (H2L1) or methylphosphonic (H4L2) acid pendant arms were synthesised and investigated in solution. The ligands form stable complexes with transition metal ions. Both ligands show high thermodynamic selectivity for divalent copper over nickel(II) and zinc(II)—K(CuL) is larger than K(Ni/ZnL) by about seven orders of magnitude. Complexation is significantly faster for the phosphonate ligand H4L2, probably due to the stronger coordination ability of the more basic phosphonate groups, which efficiently bind the metal ion in an “out‐of‐cage” complex and thus accelerate its “in‐cage” binding. The rate of CuII complexation by the phosphinate ligand H2L1 is comparable to that of cyclam itself and its derivatives with non‐coordinating substituents. Acid‐assisted decomplexation of the copper(II) complexes is relatively fast (τ1/2=44 and 42 s in 1 M aq. HClO4 at 25 °C for H2L1 and H4L2, respectively). This combination of properties is convenient for selective copper removal/purification. Thus, the title ligands were employed in the preparation of ion‐selective resins for radiocopper(II) separation. Glycidyl methacrylate copolymer beads were modified with the ligands through a diazotisation reaction. The separation ability of the modified polymers was tested with cold copper(II) and non‐carrier‐added 64Cu in the presence of a large excess of both nickel(II) and zinc(II). The experiments exhibited high overall separation efficiency leading to 60–70 % recovery of radiocopper with high selectivity over the other metal ions, which were originally present in 900‐fold molar excess. The results showed that chelating resins with properly tuned selectivity of their complexing moieties can be employed for radiocopper separation.
Design, Synthesis and Biological Evaluation of Novel N‐(4‐([2,2′:5′,2′′‐Terthiophen]‐5‐yl)‐2‐methylbut‐3‐yn‐2‐yl) Benzamide Derivatives
Authors: Zhu Youquan , Zhang Haili , Wang Danyang , Li Lei , Xu Han , Li Huabin , Ma Yuan 
Published: February 2015

AbstractOn the basis of the principle of combination of active groups, a series of novel N‐(4‐([2,2′:5′,2′′‐terthiophen]‐5‐yl)‐2‐methylbut‐3‐yn‐2‐yl) benzamide derivatives were designed, synthesized and systematically evaluated for their antiviral activity against tobacco mosaic virus (TMV). The bioassay results showed that most of these compounds displayed good anti‐TMV activity, and some of them exhibited higher antiviral activity than commercial Ningnanmycin. Especially, compound 8e with excellent anti‐TMV activity (inactivation activity, 92.3%/500 µg·mL−1; curative activity, 85.7%/500 µg·mL−1 and protection activity, 64.7%/500 µg·mL−1) emerged as a potential inhibitor of plant virus TMV. Quantitative structure‐activity relationship studies proved that the van der Waals volume (V) and electronic parameter (∑(∑σo+σp) and ∑σm) for the substituent R1 were very important for antiviral activities in this class of compounds.
Ephrin‐as are required for the topographic mapping but not laminar choice of physiologically distinct RGC types
Authors: Sweeney Neal T. , James Kiely N. , Sales Emily C. , Feldheim David A. 
Published: February 2015

ABSTRACTIn the retinocollicular projection, the axons from functionally distinct retinal ganglion cell (RGC) types form synapses in a stereotypical manner along the superficial to deep axis of the superior colliculus (SC). Each lamina contains an orderly topographic map of the visual scene but different laminae receive inputs from distinct sets of RGCs, and inputs to each lamina are aligned with the others to integrate parallel streams of visual information. To determine the relationship between laminar organization and topography of physiologically defined RGC types, we used genetic and anatomical axon tracing techniques in wild type and ephrin‐A mutant mice. We find that adjacent RGCs of the same physiological type can send axons to both ectopic and normal topographic locations, supporting a penetrance model for ephrin‐A independent mapping cues. While the overall laminar organization in the SC is unaffected in ephrin‐A2/A5 double mutant mice, analysis of the laminar locations of ectopic terminations shows that the topographic maps of different RGC types are misaligned. These data lend support to the hypothesis that the retinocollicular projection is a superimposition of a number of individual two‐dimensional topographic maps that originate from specific types of RGCs, require ephrin‐A signaling, and form independently of the other maps. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 584–593, 2015
Probing diversity within subpopulations of locomotor‐related V0 interneurons
Authors: Griener Anna , Zhang Wei , Kao Henry , Wagner Christine , Gosgnach Simon 
Published: February 2015

ABSTRACTThe V0 interneuronal population is derived from Dbx1 expressing progenitors. Initial studies on these interneurons in the mouse spinal cord demonstrated that they project commissural axons and are involved in coordinating left‐right alternation during locomotion. Subsequent work has indicated that the V0 population can be divided into genetically distinct ventral (V0V) and dorsal (V0D) subpopulations, and experimental evidence suggests that each is responsible for left‐right alternation at different locomotor speeds. In this study, we perform a series of experiments to probe the location and connectivity of these subpopulations in neonatal mice and demonstrate that they are more diverse than previously predicted. While the distribution of either subpopulation remains consistent along the extent of the lumbar spinal cord, a cluster of V0D cells lateral to the central canal receive substantial input from primary afferents. Retrograde tracing and activity dependent labeling experiments demonstrate that a group of V0 interneurons located in this same region preferentially project axons towards contralateral motoneurons via an oligosynaptic pathway, and are active during fictive locomotion. Our results suggest that this subset of V0 interneurons may be primarily responsible for coordination of left‐right alternation during locomotion. Furthermore these experiments indicate that while genetic identity is one determinant of the function of a neuron during locomotion, the specific position in which the cell is located may also play a key role. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 1189–1203, 2015
Aqueous Complexation of YIII, LaIII, NdIII, SmIII, EuIII, and YbIII with Some Heterocyclic Substituted β‐Diketones
Authors: Petrov Alexander I. , Lutoshkin Maxim A. , Taydakov Ilya V. 
Published: February 2015

AbstractThis paper deals with spectrophotometric investigation on complexation of YIII, LaIII, NdIII, SmIII, EuIII, and YbIII metal ions with six heterocyclic substituted β‐diketones. The stability constants of 36 monocomplex species was determined in aqueous solutions at 298 K and I = 0.25; it lay in the range from 5.14 to 9.76 logarithmic units. The influence of the natures of the metal and ligand on the stability constant along with the dependence of the stability constant on an ionic potential (z/r) was studied and is discussed. The acid–base, tautomeric, and dimeric equilibriums of the studied substituted β‐diketones have been investigated using UV/Vis and 1H NMR spectroscopy. Also, ab initio calculations of electronic structures of metal aquacomplex species, anions of β‐diketones, and their complex species have been carried out.
Beyond diazomethane: Alternative approaches to analyzing non‐esterified fatty acids
Authors: Potter Greg , Budge Suzanne M. , Speers R. Alex 
Published: February 2015

In many branches of lipid science, researchers are interested in non‐esterified fatty acid (NEFA) content and composition. For many years, diazomethane was the reagent of choice to selectively derivatize and then detect NEFA due to its highly specific methylation of the carboxylic acid functional group. While the activity of this derivatizing reagent is very defined, it is dangerous and can be difficult to obtain. In this brief review, we have compiled a collection of methods which allow for the detection of NEFA and hydroxy NEFA without the use of diazomethane. We have concentrated on methods that employ three distinct approaches of selective quantification/extraction, purification from total lipids and derivatization techniques.Chemical reactions that occur during selective extraction of NEFA using a quaternary ammonium salt (a) and the later pyrolytic derivatization when the mixture is placed in the hot injection port of a GC (b).
Protectin DX, a double lipoxygenase product from DHA, inhibits the production of both inflammatory cytokines and reactive oxygen species in human retinal pigment epithelium cells
Authors: Dai Yining , Zhao Chan , Liang Xiaofang , Dai Rongping , Dong Fangtian 
Published: February 2015

Oxidative stress and inflammation in retinal pigment epithelium (RPE) play important roles in the development of age‐related macular degeneration (AMD). Docosahexaenoic acid (22:6, n‐3, DHA) is highly concentrated in RPE and can be converted into the active oxygenate derivative protectin DX (PDX). The current study explored the effects of PDX on RPE cells under oxidative stress. Pretreatment with PDX significantly inhibited t‐BH‐induced reactive oxygen species (ROS) production and increased intracellular total antioxidant capability (T‐AOC) and superoxide dismutase (SOD) activity in RPE cells. Furthermore, PDX pretreatment greatly suppressed the t‐BH‐induced excessive secretion of tumor necrosis factor‐α (TNF‐α) and vascular endothelial growth factor‐A (VEGF‐A). Interestingly, peroxisome proliferator‐activated receptor‐γ coactivator‐1α (PGC‐1α), a key regulator of enzymes that detoxify ROS, was induced by PDX pretreatment, suggesting a possible mechanism that explains the antioxidant effects of PDX in RPE cells.Practical applications: DHA is highly concentrated in human RPE and photoreceptor cells. It remains controversial whether DHA can reduce the risk of progression to advanced AMD. The current study investigated the anti‐inflammatory and antioxidant effects of PDX on oxidative stress‐induced RPE cells. These results suggest the potential application of active oxygenated DHA derivatives in the prevention and treatment of AMD and other oxidative stress‐related retina diseases, such as diabetic retinopathy.DHA is highly concentrated in RPE and can be converted into the active oxygenate derivative protectin DX (PDX). Pretreatment with PDX significantly inhibited production of t‐BH‐induced reactive oxygen species (ROS) and increased capability of intracellular total antioxidant (T‐AOC) and activity of superoxide dismutase (SOD) in RPE cells. Furthermore, PDX pretreatment greatly suppressed t‐BH‐induced excessive secretion of tumor necrosis factor‐α (TNF‐α) and vascular endothelial growth factor‐A (VEGF‐A). Interestingly, peroxisome proliferator‐activated receptor‐γ coactivator‐1α (PGC‐1α), a key regulator of enzymes that detoxify ROS, was shown to be up‐regulated by PDX pretreatment, suggesting a possible mechanism underlying the antioxidant effects of PDX in RPE cells.