bluuebunny/crossref_metadata_2025_split huggingface dataset:
Smart Anisotropic Wetting Surfaces with Reversed pH‐Responsive Wetting Directions
Authors: Ge Peng , Zhang Jianglei , Liu Yongshun , Wang Shuli , Liu Wendong , Yu Nianzuo , Wu Yuxin , Zhang Junhu , Yang Bai 
Published: May 2018

AbstractSmart pH‐responsive surfaces that could autonomously induce unidirectional wetting of acid and base with reversed directions are fabricated. The smart surfaces, consisting of chemistry‐asymmetric “Janus” silicon cylinder arrays (Si‐CAs), are prepared by precise modification of functional groups on each cylinder unit. Herein, amino and carboxyl groups are chosen as typical pH‐responsive groups, owing to their protonation/deprotonation effect in response to pH of the contacted aqueous solution. One side of the Si‐CAs is modified by poly(2‐(dimethylamino)ethyl methacrylate), while the other side is modified by mixed self‐assembled monolayers of 1‐dodecanethiol and 11‐mercaptoundecanoic acid. On such surfaces, it is observed that acid and base wet in a unidirectional manner toward corresponding directions that are modified by amino or carboxyl groups, which is caused by asynchronous change of wetting property on two sides of the asymmetric structures. The as‐prepared Janus surfaces could regulate the wetting behavior of acid and base and could direct unidirectional wetting of water with reversed directions when the surfaces are treated by strong acid or base. Due to the excellent response capability, the smart surfaces are potential candidates to be applied in sensors, microfluidics, oil/water separation, and smart interfacial design.
Reversible Sodium and Lithium Insertion in Iron Fluoride Perovskites
Authors: Martin Andréa , Doublet Marie‐Liesse , Kemnitz Erhard , Pinna Nicola 
Published: May 2018

AbstractLi‐ion batteries are omnipresent in consumer electronics and are seen as the most promising technology for electric vehicles. Na‐ion batteries have emerged as viable and cheaper alternatives for stationary applications where Li‐ion batteries are too expensive. However, the larger size of sodium ion compared to lithium makes traditional positive materials for Li‐ion batteries not always suitable for the reversible insertion of sodium ions. Herein, a microwave‐assisted solution synthesis of NaFeF3 perovskite nanoparticles from presynthesized rutile FeF2 colloidal particles, sodium ethoxide, and ammonium fluoride is presented. This NaFeF3 material shows a reversible electrochemical activity of 1Na or 1Li per iron with low polarization and excellent capacity retention after 100 cycles. The unexpected reversible insertion of both sodium and lithium ions, herein studied through ex situ and operando X‐ray diffraction measurements, is attributed to a kinetic stabilization of corner‐shared cubic AxFeF3 (A = Li, Na) frameworks along the cycles involving low volume change without high thermodynamic cost as supported by a polymorphism theoretical analysis.
Ruthenium‐Catalyzed Site‐selective Enone Carbonyl Directed ortho‐C−H Activation of Aromatics and Heteroaromatics with Alkenes
Authors: Bakthadoss Manickam , Kumar Polu Vijay 
Published: May 2018

AbstractAn efficient and versatile protocol for enone carbonyl directed ortho C−H activation of aromatics and heteroaromatics with alkenes for the construction of functionalized ortho‐olefinated chalcone derivatives in excellent yields in a regio‐ and stereoselective fashion has been developed for the first time. This general protocol involves chelation assisted oxidative coupling in the presence of ruthenium catalyst through C−H bond activation. This protocol has been further emphasized by the exhibition of functional group tolerance.magnified image
Genome skimming provides new insight into the relationships in Ludwigia section Macrocarpon, a polyploid complex
Authors: Liu Shih‐Hui , Edwards Christine E. , Hoch Peter C. , Raven Peter H. , Barber Janet C. 
Published: May 2018

Premise of the StudyInterpreting relationships within groups containing polyploids, which are frequent in angiosperms, can be greatly assisted by genomic techniques. In this study, we used a genome‐skimming approach to investigate the evolutionary relationships and origins of polyploids in the monophyletic group, Ludwigia section Macrocarpon (Onagraceae), which includes diploid, tetraploid, and hexaploid taxa.MethodsWe sampled all known taxa and ploidy levels in the section and conducted shotgun sequencing. We assembled plastomes, mitochondrial sequences, and completed nuclear ribosomal regions, reconstructed phylogenies, and conducted comparative genomic analyses for plastomes to gain insights into the relationships among studied taxa.Key ResultsWithin the section, results showed that the South American diploid taxa L. bonariensis and L. lagunae were closely related. We reported the first chromosome count (2n = 4× = 32) for L. neograndiflora, which is closely related to the two South American diploid taxa, although its exact origin remains unclear. The samples of the widespread, polyploid taxon L. octovalvis do not form a monophyletic group. Both tetraploid and hexaploid L. octovalvis lineages have originated more than once. At least one tetraploid in the L. octovalvis lineage may have been involved in the origins of hexaploids. One or more extinct/unsampled intermediate tetraploids in the L. octovalvis lineages had also likely been involved in the origins of hexaploids.ConclusionsGenome skimming provided important insights into the complex evolutionary relationships within sect. Macrocarpon, but additional sampling and data from single‐copy nuclear regions are necessary to further elucidate the origins of the polyploids in this section.
Chemo‐enzymatic Total Synthesis of Oxosorbicillinol, Sorrentanone, Rezishanones B and C, Sorbicatechol A, Bisvertinolone, and (+)‐Epoxysorbicillinol
Authors: Sib Anna , Gulder Tobias A. M. 
Published: May 2018

AbstractThe sorbicillinoids are a large family of fungal natural products, many of which possess highly challenging molecular architectures. Depending on their individual structures they exhibit strong biological activities ranging from radical scavenging and anti‐infective properties to cytotoxicity. Despite the resulting strong biomedical potential of these natural products and the interest of synthetic chemists owing to their fascinating structures, many sorbicillinoids are currently not synthetically accessible, thus hampering in‐depth biological characterization and structural diversification. By using recombinant oxidoreductase SorbC and readily accessible sorbicillin‐type synthetic precursors, we have developed enantioselective, one‐pot chemo‐enzymatic routes to a broad range of sorbicillinoids, thereby establishing total syntheses of oxosorbicillinol, sorrentanone, rezishanones B and C, sorbicatechol A, bisvertinolone, and (+)‐epoxysorbicillinol.
Pt(II) complexes immobilized on polymer‐modified magnetic carbon nanotubes as a new platinum drug delivery system
Authors: Tabatabaei Rezaei Seyed Jamal , Hesami Ali , Khorramabadi Hossein , Amani Vahid , Malekzadeh Asemeh Mashhadi , Ramazani Ali , Niknejad Hassan 
Published: May 2018

We combine nanotechnology and chemical synthesis to create a novel multifunctional platinum drug delivery vehicle based on magnetic carbon nanotubes (multiwall carbon nanotubes/Fe3O4@poly(citric acid)/cis‐[(Pt(1,7‐phenanthroline)(DMSO)Cl2)]‐b‐poly(ethylene glycol) (MCNTs/FO@PC/Pt(II)‐b‐PEG)) for targeted cancer therapy. MCNTs/FO@PC/Pt(II)‐b‐PEG was conveniently prepared by conjugating cis‐[Pt(1,7‐phenanthroline)(DMSO)Cl2] complex to MCNTs/FO@PC‐b‐PEG via strong hydrogen‐bonding interactions. In comparison with free cisplatin and Pt(II) complex, MCNTs/FO@PC/Pt(II)‐b‐PEG shows higher solubility in aqueous solution and higher cytotoxicity towards human cervical cancer HeLa cells and human breast cancer MDA‐MB‐231 cells. In vitro release experiments revealed that the platinum drug‐loaded delivery system is relatively stable under physiological conditions (pH = 7.4 and 37 °C) but susceptible to acidic environments (pH = 5.6 and 37 °C) which would trigger the release of loaded drugs. Fluorescence microscopy studies revealed that this magnetic nanohybrid system possesses marked cell‐specific targeting in vitro in the presence of an external magnetic field. The results indicated that the prepared superparamagnetic MCNTs/FO@PC/Pt(II)‐b‐PEG nanohybrid system is a promising candidate for inhibiting the proliferation of cancer cells.
Hyperpolarized NMR Spectroscopy: d‐DNP, PHIP, and SABRE Techniques
Authors: Kovtunov Kirill V. , Pokochueva Ekaterina V. , Salnikov Oleg G. , Cousin Samuel F. , Kurzbach Dennis , Vuichoud Basile , Jannin Sami , Chekmenev Eduard Y. , Goodson Boyd M. , Barskiy Danila A. , Koptyug Igor V. 
Published: May 2018

AbstractThe intensity of NMR signals can be enhanced by several orders of magnitude by using various techniques for the hyperpolarization of different molecules. Such approaches can overcome the main sensitivity challenges facing modern NMR/magnetic resonance imaging (MRI) techniques, whilst hyperpolarized fluids can also be used in a variety of applications in material science and biomedicine. This Focus Review considers the fundamentals of the preparation of hyperpolarized liquids and gases by using dissolution dynamic nuclear polarization (d‐DNP) and parahydrogen‐based techniques, such as signal amplification by reversible exchange (SABRE) and parahydrogen‐induced polarization (PHIP), in both heterogeneous and homogeneous processes. The various new aspects in the formation and utilization of hyperpolarized fluids, along with the possibility of observing NMR signal enhancement, are described.
Information‐theoretic multistage sampling framework for medical audits
Authors: Musal Muzaffer , Ekin Tahir 
Published: May 2018

AbstractThe sampling resource allocation decisions for medical audits of outpatient procedures are crucial and challenging because of the large payment amounts and heterogeneity of the claims. A number of frameworks are utilized to help auditors address the trade‐offs between efficiency and cost while having valid overpayment amount estimates. As a potential improvement, this paper presents a novel information‐theoretic multistage sampling framework. In particular, we propose an iterative stratified sampling method that uses Lindley's entropy measure to evaluate the expected amount of information. We use US Medicare Part B claims outpatient payment data and investigate the versatility of the framework for different overpayment scenarios and resource allocation designs. The proposed method results in reasonable coverage and lower estimation errors for the proportion of overpaid claims and overpayment recovery amounts. Our sampling method is shown to outperform the current stratification method of practice, ie, Neyman allocation, for many scenarios. The framework also can be used to make probability statements on variables of interest, such as the number of overpaid claims.
Copper nanoclusters as fluorescence‐quenching probes for the quantitative analysis of total iodine
Authors: Cao Xueling , Li Xin , Liu Faxian , Luo Yanan , Yu Liying 
Published: May 2018

AbstractTannic acid‐coated copper nanoclusters (CuNCs@TA) were synthesized and used quantitatively to analyze iodine in kelp. Compared with other methods for iodine detection, the proposed method showed excellent performance. The iodine‐induced linear decrease in the fluorescence intensity of CuNCs@TA allowed the quantitative detection of iodine in the range 20–100 μM, and the limit of detection for iodine was 18 nM. The probe can be used for the determination of iodine in real samples with reliable and accurate results. Modified Stern–Volmer equation and thermodynamic calculation studies were used to discuss the quenching mechanism.
Proline Fingerprint in Intrinsically Disordered Proteins
Authors: Murrali Maria Grazia , Piai Alessandro , Bermel Wolfgang , Felli Isabella C. , Pierattelli Roberta 
Published: May 2018

AbstractNMR spectroscopy is one of the main techniques used for high‐resolution studies of intrinsically disordered proteins (IDPs), permitting mapping of the structural and dynamic features of all the amino acids constituting the polypeptide at atomic resolution. Only proline residues are less straightforward to characterize because they lack any amide proton, thus rendering them not directly visible in the commonly used 2D 1H,15N correlation experiments. However, proline residues are highly abundant in IDPs and can mediate important functions. In this work we present an easy and effective way to obtain fingerprints of proline residues in IDPs at high resolution.
Protein Regulation by Intrinsically Disordered Regions: A Role for Subdomains in the IDR of the HIV‐1 Rev Protein
Authors: Faust Ofrah , Grunhaus Dana , Shimshon Odelia , Yavin Eylon , Friedler Assaf 
Published: May 2018

AbstractIntrinsically disordered regions (IDRs) in proteins are highly abundant, but they are still commonly viewed as long stretches of polar, solvent‐accessible residues. Here we show that the disordered C‐terminal domain (CTD) of HIV‐1 Rev has two subregions that carry out two distinct complementary roles of regulating protein oligomerization and contributing to stability. We propose that this takes place through a delicate balance between charged and hydrophobic residues within the IDR. This means that mutations in this region, as well as the known mutations in the structured region of the protein, can affect protein function. We suggest that IDRs in proteins should be divided into subdomains similarly to structured regions, rather than being viewed as long flexible stretches.
Analysis of CO2 Emission and Economic Feasibility for a Heat‐Integrated Air Separation System
Authors: Cong Lin , Chang Liang , Liu Xinggao , Deng Xiaogang , Chen Honglong 
Published: May 2018

AbstractCryogenic air separation is a high‐energy consumption process and contributes significantly to greenhouse gas emissions. Reduction potentials of the CO2 emissions for both the full‐tower heat‐integrated air separation columns (F‐HIASC) and the top‐tower heat‐integrated air separation columns (T‐HIASC) are investigated. The optimization models of the minimum CO2 emissions are further proposed. The unit CO2 emissions of F‐HIASC and T‐HIASC can be decreased significantly compared to the conventional air separation columns (CASC). Furthermore, the capital cost and total annual cost are analyzed so as to evaluate properly the economic feasibility of HIASC. The results demonstrate that the total annual costs of F‐HIASC and T‐HIASC are much lower than that of CASC.
Enhanced SO2 Capture Performance of MnO2 by Doping with Alkali Metal Ions for Diesel Emission Control
Authors: Liu Xuecheng , Chen Lintao , Qi Gaoxiang 
Published: May 2018

AbstractGrowing concern about sulfur dioxide (SO2) emission from diesel exhaust causing a serious threat to the environment and human health necessitated enhanced desulfurization materials for dry desulfurization filters. MnO2 was modified with various alkali metal ions by impregnation to strengthen its SO2 capture capacity. The prepared materials were characterized by various technologies. Their SO2 capture capacities were measured by thermogravimetry, and the sulfate reaction mechanism was also evaluated. The results confirm that the SO2 capture performance of MnO2 could be significantly enhanced by doping with alkali metals. The prepared Li‐doped MnO2 has good SO2 trap capacity with improved absorbance being 64 % higher than that of MnO2. The grain model can be applied to explain the sulfate reaction mechanism between Li‐doped MnO2 and SO2. The activation energy was calculated by the grain model equations.
Mechanistic Insights into Selective Oxidation of Polyaromatic Compounds using RICO Chemistry
Authors: Nowicka Ewa , Hickey Niamh W. , Sankar Meenakshisundaram , Jenkins Robert L. , Knight David W. , Willock David J. , Hutchings Graham J. , Francisco Manuel , Taylor Stuart H. 
Published: May 2018

AbstractRuthenium‐ion‐catalyzed oxidation (RICO) of polyaromatic hydrocarbons (PAHs) has been studied in detail using experimental and computational approaches to explore the reaction mechanism. DFT calculations show that regioselectivity in these reactions can be understood in terms of the preservation of aromaticity in the initial formation of a [3+2] metallocycle intermediate at the most‐isolated double bond. We identify two competing pathways: C−C bond cleavage leading to a dialdehyde and C‐H activation followed by H migration to the RuOx complex to give diketones. Experimentally, the oxidation of pyrene and phenanthrene has been carried out in monophasic and biphasic solvent systems. Our results show that diketones are the major product for both phenanthrene and pyrene substrates. These diketone products are shown to be stable under our reaction conditions so that higher oxidation products (acids and their derivatives) are assigned to the competing pathway through the dialdehyde. Experiments using 18O‐labelled water do show incorporation of oxygen from the solvents into products, but this may take place during the formation of the reactive RuO4 species rather than directly during PAH oxidation. When the oxidation of pyrene is carried out using D2O, a kinetic isotope effect (KIE) is observed implying that water is involved in the rate‐determining step leading to the diketone products.
Polymorphism, Weak Interactions and Phase Transitions in Chalcogen–Phosphorus Heterocycles
Authors: Camacho Paula Sanz , Stanford Martin W. , McKay David , Dawson Daniel M. , Athukorala Arachchige Kasun S. , Cordes David B. , Slawin Alexandra M. Z. , Woollins J. Derek , Ashbrook Sharon E. 
Published: May 2018

AbstractA series of P−E‐containing heterocycles (E=chalcogen) with aromatic backbones were synthesised and characterised by single‐crystal and powder XRD, microanalysis and mass spectrometry. Solution‐ and solid‐state 31P and 77Se NMR spectroscopy revealed significant differences between the NMR parameters in solution and in the solid state, related to conformational changes in the molecules. Many compounds were shown to exhibit a number of different polymorphic structures (identified by single‐crystal XRD), although the bulk material studied by solid‐state NMR spectroscopy often contained just one major polymorph. For the unoxidised heterocycles, the presence of weak intermolecular J couplings was also investigated by DFT calculations.
Reactivity of 3,3,3‐Trifluoropropyne at Rhodium Complexes: Development of Hydroboration Reactions
Authors: von Hahmann Cortney N. , Talavera Maria , Xu Conghui , Braun Thomas 
Published: May 2018

AbstractThe rhodium compounds [Rh(C≡CCF3)(PEt3)3] (2), fac‐[RhH(C≡CCF3)2(PEt3)3] (3), and fac‐[Rh{(E)‐CH=CHCF3}(C≡CCF3)2(PEt3)3] (4) were synthesized by reactions of the rhodium(I) complexes [Rh(H)(PEt3)3] (1) and [Rh(Bpin)(PEt3)3] (5, HBpin=pinacolborane) with the alkyne 3,3,3‐trifluoropropyne. Reactivity studies of [Rh(C≡CCF3)(PEt3)3] (2) were performed with CO and 13CO to form [Rh(C≡CCF3)(CO)(PEt3)3] (7) and subsequently trans‐[Rh(C≡CCF3)(CO)(PEt3)2] (8) as well as the labeled derivatives. Using 1–4 as catalysts, hydroboration reactions selectively afforded borylated building blocks.
A Highly Stable Two‐Dimensional Copper(II) Organic Framework for Proton Conduction and Ammonia Impedance Sensing
Authors: Sun Zhibing , Yu Shihang , Zhao Lili , Wang Jifeng , Li Zifeng , Li Gang 
Published: May 2018

AbstractThis work reports the design and fabrication of a proton conductive 2D metal–organic framework (MOF), [Cu(p‐IPhHIDC)]n (1) (p‐IPhH3IDC=2‐(p‐N‐imidazol‐1‐yl)‐phenyl‐1 H‐imidazole‐4,5‐dicarboxylic acid) as an advanced ammonia impedance sensor at room temperature and 68–98 % relative humidity (RH). MOF 1 shows the optimized proton conductivity value of 1.51×10−3 S cm−1 at 100 °C and 98 % RH. Its temperature‐dependent and humidity‐dependent proton conduction properties have been explored. The large amount of uncoordinated carboxylate groups between the layers plays a vital role in the resultant conductivity. Distinctly, the fabricated MOF‐based sensor displays the required stability toward NH3, enhanced sensitivity, and notable selectivity for NH3 gas. At room temperature and 68 % RH, it gives a remarkable gas response of 8620 % to 130 ppm NH3 gas and lower detection limit of 2 ppm towards NH3 gas. It is also found that the gas response of the ammonia sensor increases linearly with the increase of NH3 gas concentration under 68–98 % RH and room temperature. Moreover, the sensor indicates excellent reversibility and selectivity toward NH3 versus N2, H2, O2, CO, CO2, benzene, and MeOH. Based on structural analyses, activation energy calculations, water and NH3 vapor absorptions, and PXRD determinations, proton conduction and NH3 sensing mechanisms are suggested.
A Novel Linking Strategy of Using 9,10‐Dihydroacridine to Construct Efficient Host Materials for Red Phosphorescent Organic Light‐Emitting Diodes
Authors: Liu Xiang‐Yang , Ma Yu‐Yang , Zhang Wenjuan , Song Bo , Ding Lei , Fung Man‐Keung , Fan Jian 
Published: May 2018

AbstractThree novel 9,10‐dihydroacridine derivatives, 4′‐(10‐methyl‐9,9‐diphenyl‐9,10‐dihydroacridin‐4‐yl)[1,1′‐biphenyl]‐4‐carbonitrile (MeAcPhCN), 4′‐(9,9,10‐triphenyl‐9,10‐dihydroacridin‐4‐yl)[1,1′‐biphenyl]‐4‐carbonitrile (PhAcPhCN), and 5‐[4‐(9,9,10‐triphenyl‐9,10‐dihydroacridin‐4‐yl)phenyl]picolinonitrile (MeAcPyCN), were prepared by the attachment of [1,1′‐biphenyl]‐4‐carbonitrile or 5‐phenylpicolinonitrile to the 4‐position of 9,10‐dihydroacridine. This special linking strategy limited the conjugation length, maintained the triplet energy, and inhibited the intermolecular charge‐transfer (ICT) characteristics of these compounds. Notably, the enhanced accepting strength of the picolinonitrile segment relative to that of benzonitrile led to relatively strong ICT characteristics, a low energy gap, and a low triplet energy for MeAcPyCN. The thermal, photophysical, electrochemical, and electroluminescent properties of these host materials were studied systematically. Consequently, (acetylacetonato)bis(2‐methyldibenzo[f,h]quinoxaline)iridium(III) [Ir(MDQ)2(acac)]‐based red phosphorescent organic light‐emitting diodes (PHOLEDs) were fabricated with these three host materials. As a result, the device hosted by MeAcPhCN showed good device performance with a maximum external quantum efficiency of 20.5 %.
Synthesis of Dihydroxyalkynyl and Dihydroxyalkyl Nucleotides as Building Blocks or Precursors for Introduction of Diol or Aldehyde Groups to DNA for Bioconjugations
Authors: Krömer Matouš , Bártová Kateřina , Raindlová Veronika , Hocek Michal 
Published: May 2018

Abstract(3,4‐Dihydroxybut‐1‐ynyl)uracil, ‐cytosine and −7‐deazaadenine 2′‐deoxyribonucleoside triphosphates (dNTPs) were prepared by direct aqueous Sonogashira cross‐coupling of halogenated dNTPs with dihydroxybut‐1‐yne and converted to 3,4‐dihydroxybutyl dNTPs through catalytic hydrogenation. Sodium periodate oxidative cleavage of dihydroxybutyl‐dUTP gave the desired aliphatic aldehyde‐linked dUTP, whereas the oxidative cleavage of the corresponding deazaadenine dNTP gave a cyclic aminal. All dihydroxyalkyl or ‐alkynyl dNTPs and the formylethyl‐dUTP were good substrates for DNA polymerases and were used for synthesis of diol‐ or aldehyde‐linked DNA. The aldehyde linked DNA was used for the labelling or bioconjugations through hydrazone formation or reductive aminations.