bluuebunny/crossref_metadata_2025_split huggingface dataset:
Self‐Collimation in Photonic Crystals: Applications and Opportunities
Authors: Noori Mina , Soroosh Mohammad , Baghban Hamed 
Published: November 2017

AbstractA comprehensive review considering recent advances in self‐collimation and its applications in optical integration is covered in the current article. Self‐collimation is compared to the conventional technique of photonic bandgap engineering to control the light propagation in photonic crystal‐based structures. It is fully discussed how the self‐collimation phenomenon can be tailored to be independent of the incident angle and polarization. This adds substantial flexibility to the structure to overcome light coupling challenges and simultaneously aids in the omission of bulk and challenging elements, including polarizers and lenses from optical integrated circuits. Additionally, designed structures have the potential to be rescaled to operate in any desired frequency range thanks to the scalability rule in the field of electromagnetics. Moreover, it is shown that one can boost the coupling efficiency by applying an anti‐reflection property to the structure, which provides not only efficient index matching but also the matching between external waves with uniform amplitude and Bloch waves with periodic amplitude.
General and Facile Route to Isomerically Pure Tricyclic Peptides Based on Templated Tandem CLIPS/CuAAC Cyclizations
Authors: Richelle Gaston J. J. , Ori Sumeet , Hiemstra Henk , van Maarseveen Jan H. , Timmerman Peter 
Published: November 2017

AbstractWe report a one‐pot ligation/cyclization technology for the rapid and clean conversion of linear peptides into tricyclic peptides that is based on using tetravalent scaffolds containing two benzyl bromide and two alkyne moieties. These react via CLIPS/CuAAC reactions with cysteines and azides in the peptide. Flexibility in the scaffolds is key to the formation of isomerically pure products as the flexible scaffolds T41 and T42 mostly promote the formation of single isomeric tricycles while the rigid scaffolds T43 and T44 do not yield clean products. There seems to be no limitation to the number and types of amino acids present as 18 canonical amino acids were successfully implemented. We also observed that azides at the peptide termini and cysteine residues in the center gave better results than compounds with the functional groups placed the other way round.
Carbonylative Coupling of Alkyl Zinc Reagents with Benzyl Bromides Catalyzed by a Nickel/NN2 Pincer Ligand Complex
Authors: Andersen Thomas L. , Donslund Aske S. , Neumann Karoline T. , Skrydstrup Troels 
Published: November 2017

AbstractAn efficient catalytic protocol for the three‐component assembly of benzyl bromides, carbon monoxide, and alkyl zinc reagents to give benzyl alkyl ketones is described, and represents the first nickel‐catalyzed carbonylative coupling of two sp3‐carbon fragments. The method, which relies on the application of nickel complexed with an NN2‐type pincer ligand and a controlled release of CO gas from a solid precursor, works well with a range of benzylic bromides. Mechanistic studies suggest the intermediacy of carbon‐centered radicals.
Cobalt‐Catalyzed Diborylation of 1,1‐disubstituted Vinylarenes: A Practical Route to Branchedgem‐Bis(boryl)alkanes
Authors: Teo Wei Jie , Ge Shaozhong 
Published: November 2017

AbstractWe report the first catalytic diborylation of 1,1‐disubstituted vinylarenes with pinacolborane using a cobalt catalyst generated from bench‐stable Co(acac)2and xantphos. A wide range of 1,1‐disubstituted vinylarenes underwent this transformation to produce the correspondinggem‐bis(boryl)alkanes in modest to high yields. This cobalt‐catalyzed reaction can be readily conducted on a gram scale without the use of a dry box and represents a practical and effective approach to prepare a wide range of branchedgem‐bis(boryl)alkanes.
Total Synthesis of (6R,10R,13R,14R,16R,17R,19S,20R,21R,24S, 25S,28S,30S,32R,33R,34R,36S,37S,39R)‐Azaspiracid‐3 Reveals Non‐Identity with the Natural Product
Authors: Kenton Nathaniel T. , Adu‐Ampratwum Daniel , Okumu Antony A. , Zhang Zhigao , Chen Yong , Nguyen Son , Xu Jianyan , Ding Yue , McCarron Pearse , Kilcoyne Jane , Rise Frode , Wilkins Alistair L. , Miles Christopher O. , Forsyth Craig J. 
Published: November 2017

AbstractA convergent and stereoselective total synthesis of the previously assigned structure of azaspiracid‐3 has been achieved by a late‐stage Nozaki–Hiyama–Kishi coupling to form the C21−C22 bond with the C20 configuration unambiguously established from l‐(+)‐tartaric acid. Postcoupling steps involved oxidation to an ynone, modified Stryker reduction of the alkyne, global deprotection, and oxidation of the resulting C1 primary alcohol to the carboxylic acid. The synthetic product matched naturally occurring azaspiracid‐3 by mass spectrometry, but differed both chromatographically and spectroscopically.
Exploring Tetrathiafulvalene–Carbon Nanodot Conjugates in Charge Transfer Reactions
Authors: Ferrer‐Ruiz Andrés , Scharl Tobias , Haines Philipp , Rodríguez‐Pérez Laura , Cadranel Alejandro , Herranz M. Ángeles , Guldi Dirk M. , Martín Nazario 
Published: November 2017

AbstractCarbon nanodots (CNDs) were synthesized using low‐cost and biocompatible starting materials such as citric acid/urea, under microwave irradiation, and constant pressure conditions. The obtained pressure‐synthesized CNDs (pCNDs) were covalently modified with photo‐ and electroactive π‐extended tetrathiafulvalene (exTTF) by means of a two‐step esterification reaction, affording pCND‐exTTF. The electronic interactions between the pCNDs and exTTF were investigated in the ground and excited states. Ultrafast pump–probe experiments assisted in corroborating that charge separation governs the deactivation of photoexcited pCND‐exTTF. These size‐regular structures, as revealed by AFM, are stable electron donor–acceptor conjugates of interest for a better understanding of basic processes such as artificial photosynthesis, catalysis, and photovoltaics, involving readily available fluorescent nanodots.
The Narrowest Band Gap Ever Observed in Molecular Ferroelectrics: Hexane‐1,6‐diammonium Pentaiodobismuth(III)
Authors: Zhang Han‐Yue , Wei Zhenhong , Li Peng‐Fei , Tang Yuan‐Yuan , Liao Wei‐Qiang , Ye Heng‐Yun , Cai Hu , Xiong Ren‐Gen 
Published: November 2017

AbstractNarrow band gaps and excellent ferroelectricity are intrinsically paradoxical in ferroelectrics as the leakage current caused by an increase in the number of thermally excited carriers will lead to a deterioration of ferroelectricity. A new molecular ferroelectric, hexane‐1,6‐diammonium pentaiodobismuth (HDA‐BiI5), was now developed through band gap engineering of organic–inorganic hybrid materials. It features an intrinsic band gap of 1.89 eV, and thus represents the first molecular ferroelectric with a band gap of less than 2.0 eV. Simultaneously, low‐temperature solution processing was successfully applied to fabricate high‐quality ferroelectric thin films based on HDA‐BiI5, for which high‐precision controllable domain flips were realized. Owing to its narrow band gap and excellent ferroelectricity, HDA‐BiI5 can be considered as a milestone in the exploitation of molecular ferroelectrics, with promising applications in high‐density data storage and photovoltaic conversion.
Triple Bonds Between Iron and Heavier Group 15 Elements in AFe(CO)3− (A=As, Sb, Bi) Complexes
Authors: Wang Jia‐Qi , Chi Chaoxian , Hu Han‐Shi , Meng Luyan , Luo Mingbiao , Li Jun , Zhou Mingfei 
Published: November 2017

AbstractHeteronuclear transition‐metal–main‐group‐element carbonyl complexes of AsFe(CO)3−, SbFe(CO)3−, and BiFe(CO)3− were produced by a laser vaporization supersonic ion source in the gas phase, and were studied by mass‐selected IR photodissociation spectroscopy and advanced quantum chemistry methods. These complexes have C3v structures with all of the carbonyl ligands bonded on the iron center, and feature covalent triple bonds between bare Group 15 elements and Fe(CO)3−. Chemical bonding analyses on the whole series of AFe(CO)3− (A=N, P, As, Sb, Bi, Mc) complexes indicate that the valence orbitals involved in the triple bonds are hybridized 3d and 4p atomic orbitals of iron, leading to an unusual (dp–p) type of transition‐metal–main‐group‐element multiple bonding. The σ‐type three‐orbital interaction between Fe 3d/4p and Group 15 np valence orbitals plays an important role in the bonding and stability of the heavier AFe(CO)3− (A=As, Sb, Bi) complexes.
A Vinyl Sulfone‐Based Fluorogenic Probe Capable of Selective Labeling of PHGDH in Live Mammalian Cells
Authors: Pan Sijun , Jang Se‐Young , Liew Si Si , Fu Jiaqi , Wang Danyang , Lee Jun‐Seok , Yao Shao Q. 
Published: November 2017

AbstractChemical probes are powerful tools for interrogating small molecule‐target interactions. With additional fluorescence Turn‐ON functionality, such probes might enable direct measurements of target engagement in live mammalian cells. DNS‐pE (and its terminal alkyne‐containing version DNS‐pE2) is the first small molecule that can selectively label endogenous 3‐phosphoglycerate dehydrogenase (PHGDH) from various mammalian cells. Endowed with an electrophilic vinyl sulfone moiety that possesses fluorescence‐quenching properties, DNS‐pE/DNS‐pE2 became highly fluorescent only upon irreversible covalent modification of PHGDH. With an inhibitory property (in vitro Ki=7.4 μm) comparable to that of known PHGDH inhibitors, our probes thus offer a promising approach to simultaneously image endogenous PHGDH activities and study its target engagement in live‐cell settings.
Stereochemical Definition of the Natural Product (6R,10R,13R, 14R,16R,17R,19S,20S,21R,24S,25S,28S,30S,32R,33R,34R,36S,37S,39R)‐Azaspiracid‐3 by Total Synthesis and Comparative Analyses
Authors: Kenton Nathaniel T. , Adu‐Ampratwum Daniel , Okumu Antony A. , McCarron Pearse , Kilcoyne Jane , Rise Frode , Wilkins Alistair L. , Miles Christopher O. , Forsyth Craig J. 
Published: November 2017

AbstractThe previously accepted structure of the marine toxin azaspiracid‐3 is revised based upon an original convergent and stereoselective total synthesis of the natural product. The development of a structural revision hypothesis, its testing, and corroboration are reported. Synthetic (6R,10R,13R,14R,16R,17R,19S,20S,21R,24S,25S,28S,30S,32R, 33R,34R,36S,37S,39R)‐azaspiracid‐3 chromatographically and spectroscopically matched naturally occurring azaspiracid‐3, whereas the previously assigned 20R epimer did not.
Uncatalyzed, Regioselective Oxidation of Saturated Hydrocarbons in an Ambient Corona Discharge
Authors: Ayrton Stephen T. , Jones Rhys , Douce David S. , Morris Mike R. , Cooks R. Graham 
Published: November 2017

AbstractAtmospheric pressure chemical ionization (APCI) in air or in nitrogen with just traces of oxygen is shown to yield regioselective oxidation, dehydrogenation, and fragmentation of alkanes. Ozone is produced from ambient oxygen in situ and is responsible for the observed ion chemistry, which includes partial oxidation to ketones and C−C cleavage to give aldehydes. The mechanism of oxidation is explored and relationships between ionic species produced from individual alkanes are established. Unusually, dehydrogenation occurs by water loss. Competitive incorporation into the hydrocarbon chain of nitrogen versus oxygen as a mode of ionization is also demonstrated.
Total Syntheses of Daphenylline, Daphnipaxianine A, and Himalenine D
Authors: Chen Yu , Zhang Wenhao , Ren Lu , Li Jian , Li Ang 
Published: November 2017

AbstractWe report the total syntheses of daphenylline (1), daphnipaxianine A (5), and himalenine D (6), three Daphniphyllum alkaloids from the calyciphylline A subfamily. A pentacyclic triketone was prepared by using atom‐transfer radical cyclization and the Lu [3+2] cycloaddition as key steps. Inspired by the proposed biosynthetic relationship between 1 and another calyciphylline A type alkaloid, we developed a ring‐expansion/aromatization/aldol cascade to construct the tetrasubstituted benzene moiety of 1. The versatile triketone intermediate was also elaborated into 5 and 6 through a C=C bond migration/aldol cyclization approach.
CD4+ and B Lymphocyte Expression Quantitative Traits at Rheumatoid Arthritis Risk Loci in Patients With Untreated Early Arthritis
Authors: Thalayasingam Nishanthi , Nair Nisha , Skelton Andrew J. , Massey Jonathan , Anderson Amy E. , Clark Alexander D. , Diboll Julie , Lendrem Dennis W. , Reynard Louise N. , Cordell Heather J. , Eyre Stephen , Isaacs John D. , Barton Anne , Pratt Arthur G. 
Published: November 2017

ObjectiveRheumatoid arthritis (RA) is a genetically complex disease of immune dysregulation. This study sought to gain further insight into the genetic risk mechanisms of RA by conducting an expression quantitative trait locus (eQTL) analysis of confirmed genetic risk loci in CD4+ T cells and B cells from carefully phenotyped patients with early arthritis who were naive to therapeutic immunomodulation.MethodsRNA and DNA were isolated from purified B and/or CD4+ T cells obtained from the peripheral blood of 344 patients with early arthritis. Genotyping and global gene expression measurements were carried out using Illumina BeadChip microarrays. Variants in linkage disequilibrium (LD) with non‐HLA RA single‐nucleotide polymorphisms (defined as r2 ≥ 0.8) were analyzed, seeking evidence of cis‐ or trans‐eQTLs according to whether the associated probes were or were not within 4 Mb of these LD blocks.ResultsGenes subject to cis‐eQTL effects that were common to both CD4+ and B lymphocytes at RA risk loci were FADS1, FADS2, BLK, FCRL3, ORMDL3, PPIL3, and GSDMB. In contrast, those acting on METTL21B, JAZF1, IKZF3, and PADI4 were unique to CD4+ lymphocytes, with the latter candidate risk gene being identified for the first time in this cell subset. B lymphocyte–specific eQTLs for SYNGR1 and CD83 were also found. At the 8p23 BLK–FAM167A locus, adjacent genes were subject to eQTLs whose activity differed markedly between cell types; in particular, the FAM167A effect displayed striking B lymphocyte specificity. No trans‐eQTLs approached experiment‐wide significance, and linear modeling did not identify a significant influence of biologic covariates on cis‐eQTL effect sizes.ConclusionThese findings further refine the understanding of candidate causal genes in RA pathogenesis, thus providing an important platform from which downstream functional studies, directed toward particular cell types, may be prioritized.
Polyoxometalate and Resin‐Derived P‐Doped Mo2C@N‐Doped Carbon as a Highly Efficient Hydrogen‐Evolution Reaction Catalyst at All pH Values
Authors: Yan Gang , Feng Xiaojia , Khan Shifa Ullah , Xiao Liguang , Xi Wenguang , Tan Huaqiao , Ma Yuanyuan , Zhang Lunan , Li Yangguang 
Published: November 2017

AbstractA new type of P‐doped Mo2C coated by N‐doped carbon (P‐Mo2C@NC) has been successfully prepared by calcining a mixture of H3[PMo12O40] polyoxometalates (POMs) and urea‐formaldehyde resin under an N2 atmosphere. Urea‐formaldehyde resin not only serves as the carbon source to ensure carbonization but also facilitates the uniform distribution of POM precursors, which efficiently avoid the aggregation of Mo2C particles at high temperatures. TEM analysis revealed that the average diameter of the Mo2C particles was about 10 nm, which is coated by a few‐layer N‐doped carbon sheet. The as‐prepared P‐Mo2C@NC displayed excellent hydrogen‐evolution reaction (HER) performance and long‐term stability in all pH environments. To reach a current density of 10 mA cm−2, only 109, 159, and 83 mV were needed for P‐Mo2C@NC in 0.5 m H2SO4 (pH 0), 0.1 m phosphate buffer (pH 7), and 1 m KOH (pH 14), respectively. This could provide a high‐yield and low‐cost method to prepare uniform nanosized molybdenum carbides with highly efficient and stable HER performance.
Robust Optimal Control of Nonlinear Systems With System Disturbance During Feedback Disruption
Authors: Oh Sang‐Young , Choi Ho‐Lim 
Published: November 2017

AbstractIn this paper, a robust optimal control problem of nonlinear systems with system disturbance during feedback disruption is considered. This is an extended work of previous time‐delay optimal control results, by adding external disturbance in the considered system. It is shown that there exists an optimal input signal which keeps the performance error within the specified bound for the longest time. Then, it is shown that such an optimal input signal can be approximated by an implementable bang‐bang input signal in terms of control performance. Two examples are given for illustration.
Robust Control of Permanent Magnet Synchronous Machine Based on Passivity Theory
Authors: Mocanu Razvan , Onea Alexandru 
Published: November 2017

AbstractThis paper presents a robust control strategy for a Permanent Magnet Synchronous Machine (PMSM) based on passivity theory. Pre‐control terms ensure robustness to variation of parameters. The nominal electrical and mechanical dynamics are treated separately and a cascade structure is obtained. A comparative analysis is done in Matlab‐Simulink with a Simple Adaptive Control (SAC) strategy in terms of settling time, stationary error, time response and energy efficiency. Improvements of the proposed Passivity Based Control (PBC) strategy are shown in comparison with some other PBC controllers.
The adenosine A2A receptor agonist, CGS 21680, attenuates a probabilistic reversal learning deficit and elevated grooming behavior in BTBR mice
Authors: Amodeo Dionisio A. , Cuevas Laura , Dunn Jeffrey T. , Sweeney John A. , Ragozzino Michael E. 
Published: November 2017

Restricted interests and repetitive behaviors (RRBs) are a defining feature of autism spectrum disorder (ASD). To date there are limited options for treating this core symptomology. Treatments that stimulate adenosine A2A receptors may represent a promising approach for reducing RRBs in ASD. This is because A2A receptors are expressed on striatal neurons of the basal ganglia indirect pathway. Under activation of this pathway has been associated with RRBs while activation of A2A receptors leads to increased activity of the indirect basal ganglia pathway. The present studies investigated whether acute, systemic treatment with CGS21680, an A2A receptor agonist attenuates elevated self‐grooming and a probabilistic reversal learning deficit in the BTBR T+ Itpr3tf/J (BTBR) mouse model of idiopathic autism. The effects of this treatment were also investigated in C57BL/6J (B6) mice as a comparison strain. Using a spatial reversal learning test with 80/20 probabilistic feedback, comparable to one in which ASD individuals exhibit deficits, CGS 21680 (0.005 and 0.01mg/kg) attenuated a reversal learning deficit in BTBR mice. Enhancement in probabilistic reversal learning performance resulted from CGS 21680 improving the consistent maintenance of new adaptive behavioral choice patterns after reversal. CGS 21680 at 0.01 mg, but not 0.005 mg, also reduced self‐grooming behavior in BTBR mice. CGS 21680 did not affect self‐grooming or reversal learning in B6 mice. These findings demonstrate that A2A receptor agonists may be a promising receptor target in the treatment of RRBs in ASD. Autism Res 2018, 11: 223–233. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.Lay SummaryThe present experiments determined whether the drug, CGS 21680, that facilitates activation of adenosine A2A receptors in the brain, would reduce repetitive and inflexible behaviors in the BTBR mouse model of idiopathic autism. CGS 21680 treatment in BTBR mice reduced repetitive and inflexible behaviors. In the control C57BL/6J (B6) mouse strain, CGS 21680 did not affect performance. These findings suggest that stimulation of brain adenosine A2A receptors may be a promising therapeutic strategy in ASD.
A detailed characterization of congenital defects and mortality following moderate X‐ray doses during neurulation
Authors: Craenen Kai , Verslegers Mieke , Buset Jasmine , Baatout Sarah , Moons Lieve , Benotmane Mohammed Abderrafi 
Published: November 2017

BackgroundBoth epidemiological and animal studies have previously indicated a link between in utero radiation exposure and birth defects such as microphthalmos, anophthalmos, and exencephaly. However, detailed knowledge on embryonic radiosensitivity during different stages of neurulation is limited, especially in terms of neural tube defect and eye defect development.MethodsTo assess the most radiosensitive stage during neurulation, pregnant C57BL6/J mice were X‐irradiated (0.5 Gy or 1.0 Gy) at embryonic days (E)7, E7.5, E8, E8.5, or E9. Next, the fetuses were scored macroscopically for various defects and prenatal resorptions/deaths were counted. In addition, cranial skeletal development was ascertained using the alcian‐alizarin method. Furthermore, postnatal/young adult survival was followed until 5 weeks (W5) of age, after X‐irradiation at E7.5 (0.1 Gy, 0.5 Gy, or 1.0 Gy). In addition, body and brain weights were registered at adult age (W10) following X‐ray exposure at E7.5 (0.1 Gy, 0.5 Gy).ResultsSeveral malformations, including microphthalmos and exencephaly, were most evident after irradiation at E7.5, with significance starting respectively at 0.5 Gy and 1.0 Gy. Prenatal mortality and weight were significantly affected in all irradiated groups. Long‐term follow‐up of E7.5 irradiated animals revealed a reduction in survival at 5 weeks of age after high dose exposure (1.0 Gy), while lower doses (0.5 Gy, 0.1 Gy) did not affect brain and body weight at postnatal week 10.ConclusionsWith this study, we gained more insight in radiosensitivity throughout neurulation, and offered a better defined model to further study radiation‐induced malformations and the underlying mechanisms.
Genetic susceptibility to thalidomide embryopathy in humans: Study of candidate development genes
Authors: Gomes Julia do Amaral , Kowalski Thayne Woycinck , Fraga Lucas Rosa , Tovo‐Rodrigues Luciana , Sanseverino Maria Teresa Vieira , Schuler‐Faccini Lavínia , Vianna Fernanda Sales Luiz 
Published: November 2017

AbstractThalidomide is a drug used worldwide for several indications, but the molecular mechanisms of its teratogenic property are not fully understood. Studies in animal models suggest the oxidative stress, the inhibition of angiogenesis, and the binding to E3‐ubiquitin ligase complex as mechanisms by which thalidomide can change the expression of genes important to embryonic development. In this study, seven polymorphisms in genes related to development (FGF8, FGF10, BMP4, SHH, TP53, TP63, and TP73) were analyzed in people with thalidomide embryopathy (TE) and compared to people without malformations. The sample consisted of 36 people with TE and 135 unrelated and nonsyndromic people who had their DNA genotyped by PCR real‐time. Although no allelic or genotypic differences were observed between the groups, we hypothesized that other regions in these genes and related genes may play an important role in thalidomide teratogenesis, which is known to have a genetic contribution. Identifying such molecular mechanisms is essential for the development of a molecule that will be analogue to thalidomide but safe enough to avoid the emergence of new cases of TE.