bluuebunny/crossref_metadata_2025_split huggingface dataset:
When Molecular Probes Meet Self‐Assembly: An Enhanced Quenching Effect
Authors: Ren Chunhua , Wang Huaimin , Mao Duo , Zhang Xiaoli , Fengzhao Qianqi , Shi Yang , Ding Dan , Kong Deling , Wang Ling , Yang Zhimou 
Published: February 2015

AbstractWe demonstrate that the incorporation of one or two amino acids of phenylalanine (F) or 4‐fluoro phenylalanine (fF) will greatly lower the background fluorescence intensities of conventional quenched probes with quenchers. This enhanced quenching effect was due to the synergetic effect of the aggregation caused quenching and the presence of a quencher. Such strategy will not greatly affect the enzyme recognition properties to the probes. We also demonstrated that our self‐assembled nanoprobe with the enhanced quenching effect showed a better performance in cells for the detection of cell apoptosis than the unassembled probes. Our study demonstrates that using molecular self‐assembly can optimize and improve the performance of molecular probes and it provides a simple but very useful strategy to boost the signal‐to‐noise ratios of fluorescence probes.
A Functionalized Ag2S Molecular Architecture: Facile Assembly of the Atomically Precise Ferrocene‐Decorated Nanocluster [Ag74S19(dppp)6(fc(C{O}OCH2CH2S)2)18]
Authors: Liu Yiyi , Khalili Najafabadi Bahareh , Azizpoor Fard Mahmood , Corrigan John F. 
Published: February 2015

AbstractA ferrocene‐based dithiol 1,1′‐[fc(C{O}OCH2CH2SH)2] has been prepared and treated with a AgI salt to form the stable dithiolate compound [fc(C{O}OCH2CH2SAg)2]n (fc=[Fe(η5‐C5H4)2]). This is used as a reagent for the preparation of the nanocluster [Ag74S19(dppp)6(fc(C{O}OCH2CH2S)2)18] which was obtained in good yield (dppp=1,3‐bis(diphenylphosphino)propane).
Ion‐Specific Oil Repellency of Polyelectrolyte Multilayers in Water: Molecular Insights into the Hydrophilicity of Charged Surfaces
Authors: Liu Xiaokong , Leng Chuan , Yu Li , He Ke , Brown Lauren Joan , Chen Zhan , Cho Jinhan , Wang Dayang 
Published: February 2015

AbstractSurface wetting on polyelectrolyte multilayers (PEMs), prepared by alternating deposition of polydiallyldimethylammonium chloride (PDDA) and poly(styrene sulfonate) (PSS), was investigated mainly in water‐solid‐oil systems. The surface‐wetting behavior of as‐prepared PEMs was well correlated to the molecular structures of the uncompensated ionic groups on the PEMs as revealed by sum frequency generation vibrational and X‐ray photoelectron spectroscopies. The orientation change of the benzenesulfonate groups on the PSS‐capped surfaces causes poor water wetting in oil or air and negligible oil wetting in water, while the orientation change of the quaternized pyrrolidine rings on the PDDA‐capped surfaces hardly affects their wetting behavior. The underwater oil repellency of PSS‐capped PEMs was successfully harnessed to manufacture highly efficient filters for oil‐water separation at high flux.
113Cd NMR Experiments Reveal an Unusual Metal Cluster in the Solution Structure of the Yeast Splicing Protein Bud31p
Authors: van Roon Anne‐Marie M. , Yang Ji‐Chun , Mathieu Daniel , Bermel Wolfgang , Nagai Kiyoshi , Neuhaus David 
Published: February 2015

AbstractEstablishing the binding topology of structural zinc ions in proteins is an essential part of their structure determination by NMR spectroscopy. Using 113Cd NMR experiments with 113Cd‐substituted samples is a useful approach but has previously been limited mainly to very small protein domains. Here we used 113Cd NMR spectroscopy during structure determination of Bud31p, a 157‐residue yeast protein containing an unusual Zn3Cys9 cluster, demonstrating that recent hardware developments make this approach feasible for significantly larger systems.
Structural Characterization of a Hydroperoxo Nickel Complex and Its Autoxidation: Mechanism of Interconversion between Peroxo, Superoxo, and Hydroperoxo Species
Authors: Rettenmeier Christoph A. , Wadepohl Hubert , Gade Lutz H. 
Published: February 2015

AbstractPincer‐stabilized nickel(I) complexes readily react with molecular oxygen to form dinuclear 1,2‐μ‐peroxo‐bridged nickel(II) complexes, which are the major components of a dynamic equilibrium with the corresponding mononuclear superoxo species. The peroxo complexes further react with hydrogen peroxide to give the corresponding nickel(II) hydroperoxides. One of these hitherto elusive species was characterized by X‐ray diffraction for the first time [O–O bond length: 1.492(2) Å].
Formation of Nickel Sulfide Nanoframes from Metal–Organic Frameworks with Enhanced Pseudocapacitive and Electrocatalytic Properties
Authors: Yu Xin‐Yao , Yu Le , Wu Hao Bin , Lou Xiong Wen (David) 
Published: February 2015

AbstractNanoframe‐like hollow structures with unique three‐dimensional (3D) open architecture hold great promise for various applications. Current research efforts mainly focus on frame‐like noble metals and metal oxides. However, metal sulfides with frame‐like nanostructures have been rarely reported. Starting from metal–organic frameworks (MOFs), we demonstrate a novel structure‐induced anisotropic chemical etching/anion exchange method to transform Ni‐Co Prussian blue analogue (PBA) nanocubes into NiS nanoframes with tunable size. The reaction between Ni‐Co PBA nanocube templates and Na2S in solution leads to the formation of well‐defined NiS nanoframes. The different reactivity between the edges and the plane surface of the Ni‐Co PBA nanocubes is found to be the key factor for the formation of NiS nanoframes. Benefitting from their structural merits including 3D open structure, small size of primary nanoparticles, high specific surface area, and good structural robustness, the as‐derived NiS nanoframes manifest excellent electrochemical performance for electrochemical capacitors and hydrogen evolution reaction in alkaline electrolyte.
Gold‐Catalyzed Cycloaddition Reactions of Ethyl Diazoacetate, Nitrosoarenes, and Vinyldiazo Carbonyl Compounds: Synthesis of Isoxazolidine and Benzo[b]azepine Derivatives
Authors: Pagar Vinayak Vishnu , Liu Rai‐Shung 
Published: February 2015

AbstractGold‐catalyzed cycloadditions of ethyl diazoacetate, nitrosoarenes, and vinyldiazo carbonyl species to yield isoxazolidine derivatives stereoselectively are described. Treatment of these isoxazolidine products with the same catalyst results in a novel 1,2‐H shift/[3,3] rearrangement to give benzo[b]azepine compounds. The mechanism of this skeletal rearrangement is elucidated with deuterium‐labeling experiments.
Nanomolar Inhibitors of the Transcription Factor STAT5b with High Selectivity over STAT5a
Authors: Elumalai Nagarajan , Berg Angela , Natarajan Kalaiselvi , Scharow Andrej , Berg Thorsten 
Published: February 2015

AbstractSrc homology 2 (SH2) domains play a central role in signal transduction. Although many SH2 domains have been validated as drug targets, their structural similarity makes development of specific inhibitors difficult. The cancer‐relevant transcription factors STAT5a and STAT5b are particularly challenging small‐molecule targets because their SH2 domains are 93 % identical on the amino acid level. Here we present the natural product‐inspired development of the low‐nanomolar inhibitor Stafib‐1, as the first small molecule which inhibits the STAT5b SH2 domain (Ki=44 nM) with more than 50‐fold selectivity over STAT5a. The binding site of the core moiety of Stafib‐1 was validated by functional analysis of point mutants. A prodrug of Stafib‐1 was shown to inhibit STAT5b with high selectivity over STAT5a in tumor cells. Stafib‐1 provides the first demonstration that naturally occurring SH2 domains with more than 90 % sequence identity can be selectively targeted with small organic molecules.
Affinity Screening Using Competitive Binding with Fluorine‐19 Hyperpolarized Ligands
Authors: Kim Yaewon , Hilty Christian 
Published: February 2015

AbstractFluorine‐19 NMR and hyperpolarization form a powerful combination for drug screening. Under a competitive equilibrium with a selected fluorinated reporter ligand, the dissociation constant (KD) of other ligands of interest is measurable using a single‐scan Carr–Purcell–Meiboom–Gill (CPMG) experiment, without the need for a titration. This method is demonstrated by characterizing the binding of three ligands with different affinities for the serine protease trypsin. Monte Carlo simulations show that the highest accuracy is obtained when about one‐half of the bound reporter ligand is displaced in the binding competition. Such conditions can be achieved over a wide range of affinities, allowing for rapid screening of non‐fluorinated compounds when a single fluorinated ligand for the binding pocket of interest is known.
Cobalt(III)‐Catalyzed Directed CH Coupling with Diazo Compounds: Straightforward Access towards Extended π‐Systems
Authors: Zhao Dongbing , Kim Ju Hyun , Stegemann Linda , Strassert Cristian A. , Glorius Frank 
Published: February 2015

AbstractThe first highly efficient and scalable cobalt‐catalyzed directed CH functionalization with carbene precursors is presented. This methodology provides a modular route towards a new class of conjugated polycyclic hydrocarbons with tunable emission wavelengths both in solution and in the solid state.
Organoaluminum‐Mediated Direct Cross‐Coupling Reactions
Authors: Minami Hiroki , Saito Tatsuo , Wang Chao , Uchiyama Masanobu 
Published: February 2015

AbstractWe present a direct cross‐coupling reaction between arylaluminum compounds (ArAlMe2⋅LiCl) and organic halides RX (R=aryl, alkenyl, alkynyl; X=I, Br, and Cl) without any external catalyst. The reaction takes place smoothly, simply upon heating, thereby enabling the efficient and chemo‐/stereoselective formation of biaryl, alkene, and alkyne coupling products with broad functional group compatibility.
Synthesis of Well‐Defined Adenosine Diphosphate Ribose Oligomers
Authors: Kistemaker Hans A. V. , Lameijer Lucien N. , Meeuwenoord Nico J. , Overkleeft Herman S. , van der Marel Gijsbert A. , Filippov Dmitri V. 
Published: February 2015

AbstractThe post‐translational modification of proteins that is known as adenosine diphosphate ribosylation (ADPr) regulates a wide variety of important biological processes, such as DNA‐damage repair and cellular metabolism. This modification is also involved in carcinogenesis and the process of aging. Therefore, a better understanding of the function of ADP‐ribosylation is crucial for the development of novel therapeutics. To facilitate the elucidation of the biology of ADPr, the availability of well‐defined fragments of poly(ADP‐ribose) is essential. Herein we report a solid‐phase synthetic approach for the preparation of ADP‐ribose oligomers of exactly defined length. The methodology is exemplified by the first reported synthesis of an ADP‐ribose dimer and trimer.
Dehydrogenative Homocoupling of Terminal Alkenes on Copper Surfaces: A Route to Dienes
Authors: Sun Qiang , Cai Liangliang , Ding Yuanqi , Xie Lei , Zhang Chi , Tan Qinggang , Xu Wei 
Published: February 2015

AbstractHomocouplings of hydrocarbon groups including alkynyl (sp1), alkyl (sp3), and aryl (sp2) have recently been investigated on surfaces with the interest of fabricating novel carbon nanostructures/nanomaterials and getting fundamental understanding. Investigated herein is the on‐surface homocoupling of an alkenyl group which is the last elementary unit of hydrocarbons. Through real‐space direct visualization (scanning tunneling microscopy imaging) and density functional theory calculations, the two terminal alkenyl groups were found to couple into a diene moiety on copper surfaces, and is contrary to the common dimerization products of alkenes in solution. Furthermore, detailed DFT‐based transition‐state searches were performed to unravel this new reaction pathway.
Electrochemically Mediated Atom Transfer Radical Polymerization from a Substrate Surface Manipulated by Bipolar Electrolysis: Fabrication of Gradient and Patterned Polymer Brushes
Authors: Shida Naoki , Koizumi Yuki , Nishiyama Hiroki , Tomita Ikuyoshi , Inagi Shinsuke 
Published: February 2015

AbstractWe report the first ever use of electrochemically mediated atom transfer radical polymerization (eATRP) employing a bipolar electrochemical method for the fabrication of both gradient and patterned polymer brushes. A potential gradient generated on a bipolar electrode allowed the formation of a concentration gradient of a CuI polymerization catalyst through the one‐electron reduction of CuII, resulting in the gradient growth of poly(NIPAM) brushes from an initiator‐modified substrate surface set close to a bipolar electrode. These polymer brushes could be fabricated in three‐dimensional gradient shapes with control over thickness, steepness, and modified area by varying the electrolytic conditions. Moreover, by site‐selective application of potential during bipolar electrolysis, a polymer brush with a circular pattern was successfully formed. Polymerization was achieved using both a polar monomer (NIPAM) and a nonpolar monomer (MMA) with the eATRP system.
New Insights into the Hexaphenylethane Riddle: Formation of an α,o‐Dimer
Authors: Uchimura Yasuto , Takeda Takashi , Katoono Ryo , Fujiwara Kenshu , Suzuki Takanori 
Published: February 2015

AbstractUpon reduction of a 1H‐cyclobuta[de]naphthalene‐4,5‐diylbis(diarylmethylium) species, a new CC bond is formed between the Cα and Cortho atoms of the two chromophores, which presents an unprecedented coupling pattern for the dimerization of two trityl units. By attaching an annulated cyclobutane ring at the opposite peri position of the naphthalene core, the distance between the Cα carbon atoms was elongated beyond the limit of σ‐bond formation through “scissor effects”. The suppression of CαCα bond formation, which would lead to hexaphenylethane‐type compounds, is key to the first successful isolation of the α,o‐adducts. The 5‐diarylmethylene‐6‐triarylmethyl‐1,3‐cyclohexadiene unit in the α,o‐adducts is stable, and isomerization of the cyclohexadiene unit into an aromatic system was not observed. The newly formed CαCortho bond was cleaved upon two‐electron oxidation to regenerate the dicationic dye.
Establishing marine protected areas through bottom‐up processes: insights from two contrasting initiatives in Chile
Authors: Oyanedel Rodrigo , Marín Andrés , Castilla Juan Carlos , Gelcich Stefan 
Published: February 2015

AbstractBottom‐up participatory processes to create and manage no‐take marine protected areas have been proposed as a way to scale‐up marine conservation and deal with the lack of support and compliance of top‐down conservation approaches. However, bottom‐up conservation does not always lead to positive outcomes, thus it is increasingly important to understand the conditions that determine the establishment and implementation of these initiatives.Establishment and implementation processes were compared empirically for two contrasting bottom‐up no‐take marine protected areas that have been developing under the same political setting, however, one has been successful and the other has stalled.Using mixed methods, stakeholders' (a) motivations to participate in the no‐take marine protected area initiatives, (b) communication, support and information flow networks, (c) perceived participation, and (d) satisfaction with the establishment process of the bottom‐up no‐take marine protected areas, were assessed.Non‐significant differences were found between the two initiatives in terms of stakeholders' motivations to create a no‐take marine protected area.Significant differences were found in stakeholders' communication, support and information flow networks, in addition to differences in participation, and satisfaction with the establishment and implementation process.Results highlight that for the implementation and consolidation of bottom‐up no‐take marine protected areas initiatives, common interests do not necessarily lead to common action, partnerships will not emerge automatically in response to potential benefits.Understanding disparities in participation, information sharing and communication are key aspects which must be considered for creating and supporting successful marine protected areas based on bottom‐up participatory processes.Copyright © 2015 John Wiley & Sons, Ltd.
Operational interactions between South American sea lions and gillnet fishing in southern Brazil
Authors: Machado Rodrigo , Ott Paulo Henrique , Moreno Ignacio Benites , Danilewicz Daniel , Tavares Maurício , Crespo Enrique Alberto , Siciliano Salvatore , Rosa De Oliveira Larissa 
Published: February 2015

Abstract

This study describes operational interactions between coastal gillnet fishing and South American sea lions (Otaria flavescens) off the southern Brazilian coast.
In total, 263 onboard surveys were carried out during three periods between 1992 and 2012 in fishing boats from two harbours on the northern coast of Rio Grande do Sul State: Passo de Torres (29°19'S; 49°43'W) and Imbé (29°58'S; 50°07'W).
Interactions of South American sea lions were observed in 116 (24.0%) out of 484 fishing operations. These interactions were more frequent in fishing boats from Passo de Torres (frequency of occurrence FO = 42.8%) than those from Imbé (FO = 14.8%; P < 0.001) and during autumn and winter months.
Interactions between South American sea lions and fishing activities with fixed bottom gillnets in Imbé were most frequent during period III of the study (2011/2012) (FO = 52.0%; P = 0.032).
These results demonstrated that interactions are not as high as reported/complained about by the local fishermen who tend to exaggerate the impact of these interactions.
It is suggested that reduced fish stock and increased fishing effort during recent decades is raising the frequency of encounters with South American sea lions during fishing activities off the southern Brazilian coast. Therefore, the implementation of fishery management measures that reduce fishing effort and that integrate environmental education programmes are essential to reduce conflicts between fishing activities and the sea lions in the region.
Copyright © 2015 John Wiley & Sons, Ltd.
Analysis of fine‐scale daily movement patterns of juvenile Pristis pectinata within a nursery habitat
Authors: Hollensead Lisa D. , Grubbs R. Dean , Carlson John K. , Bethea Dana M. 
Published: February 2015

Abstract

Habitat use studies can be used to investigate ecological and behavioural patterns of animals and serve as useful tools for conservation planners. However, specific habitats essential to survival can be difficult to determine for highly mobile marine animals, especially when these species are rare or endangered.
Active acoustic tracking telemetry was used to determine daily activity spaces and rates of movement of juvenile smalltooth sawfish (Pristis pectinata) in critical habitat areas of south‐west Florida, USA.
Activity space size and rates of movement were positively related with the size of the area where the animal was tracked. Overall, activity spaces were small and ranged from 0.07–0.17 km2 using 95% minimum convex polygons, 0.01–0.16 km2 based on 50% kernel density estimates (KDE), and 0.08–0.68 km2 based on 95% KDE. Rates of movement ranged from 2.4 to 6.1 m min–1.
There were no detectable differences in activity space or rates of movement between ebb and flood tide or high or low tide. Activity space decreased and rates of movement increased at night, possibly related to nocturnal foraging behaviour or predator avoidance. Comparisons of tracked animal locations and random locations suggested there was selection for those habitats in close proximity to mangrove shoreline.
Though daily activity spaces were small, juvenile smalltooth sawfish did exhibit a daily expansion in activity space over the monitoring period.
Copyright © 2015 John Wiley & Sons, Ltd.
Micro‐ and Nano‐Technologies for Lipid Bilayer‐Based Ion‐Channel Functional Assays
Authors: Hirano‐Iwata Ayumi , Ishinari Yutaka , Yamamoto Hideaki , Niwano Michio 
Published: February 2015

AbstractIon channel proteins provide gated pores that allow ions to passively flow across cell membranes. Owing to their crucial roles in regulating transmembrane ion flow, ion channel proteins have attracted the attention of pharmaceutical investigators as drug targets for use in the studies of both therapeutics and side effects. In this review, we discuss the current technologies that are used in the formation of ion channel‐integrated bilayer lipid membranes (BLMs) in microfabricated devices as a potential platform for next‐generation drug screening systems. Advances in BLM fabrication methodology have allowed the preparation of BLMs in sophisticated formats, such as microfluidic, automated, and/or array systems, which can be combined with channel current recordings. A much more critical step is the integration of the target channels into BLMs. Current technologies for the functional reconstitution of ion channel proteins are presented and discussed. Finally, the remaining issues of the BLM‐based methods for recording ion channel activities and their potential applications as drug screening systems are discussed.
Fluorescent probe for detection of Cu2+ using core‐shell CdTe/ZnS quantum dots
Authors: Bian Wei , Wang Fang , Zhang Hao , Zhang Lin , Wang Li , Shuang Shaomin 
Published: February 2015

AbstractCore‐shell CdTe/ZnS quantum dots capped with 3‐mercaptopropionic acid (MPA) were successfully synthesized in aqueous medium by hydrothermal synthesis. These quantum dots have advantages compared to traditional quantum dots with limited biological applications, high toxicity and tendency to aggregate. The concentration of Cu2+ has a significant impact on the fluorescence intensity of quantum dots (QDs), therefore, a rapid sensitive and selective fluorescence probe has been proposed for the detection of Cu2+ in aqueous solution. Under optimal conditions, the fluorescence intensity of CdTe/ZnS QDs was linearly proportional to the concentration of Cu2+ in the range from 2.5 × 10–9 M to 17.5 × 10–7 M with the limit of 1.5 × 10–9 M and relative standard deviation of 0.23%. The quenching mechanism is static quenching with recoveries of 97.30–102.75%. Copyright © 2015 John Wiley & Sons, Ltd.
Proteopedia: Rossmann fold: A beta‐alpha‐beta fold at dinucleotide binding sites
Authors: Hanukoglu Israel 
Published: February 2015

AbstractThe Rossmann fold is one of the most common and widely distributed super‐secondary structures. It is composed of a series of alternating beta strand (β) and alpha helical (α) segments wherein the β‐strands are hydrogen bonded forming a β‐sheet. The initial beta‐alpha‐beta (βαβ) fold is the most conserved segment of Rossmann folds. As this segment is in contact with the ADP portion of dinucleotides such as FAD, NAD, and NADP it is also called as an "ADP‐binding βαβ fold". The Proteopedia entry on the Rossmann fold (Available at: http://proteopedia.org/w/Rossmann_fold) was generated to illustrate several structural aspects of super families of FAD and NAD(P) binding proteins: (1) The coenzymes FAD and NAD(P) share the basic adenosine diphosphate (ADP) structure. (2) The βαβ fold motif that is common to both FAD and NAD(P) binding enzymes accommodates the common ADP component of these two coenzymes. (3) In both FAD and NAD(P) binding sites, the tight turn between the first β‐strand and the α‐helix is in contact with the two phosphate groups of ADP. (4) This hairpin curve includes the first two conserved glycines (Gly‐x‐Gly) that allow the sharp turn of the polypeptide backbone. (5) The two β‐strands of the βαβ fold may constitute the core of a larger β‐sheet that may include up to seven β‐strands generally in parallel orientation. (6) The structures of segments between additional strands vary greatly and may be composed of a variety of structures such as multiple short helices or coils. © 2015 by The International Union of Biochemistry and Molecular Biology, 43(3):206–209, 2015.