bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcriptomics insights into the genetic regulation of root apical meristem exhaustion and determinate primary root growth in Pachycereus pringlei (Cactaceae)
Authors: Rodriguez-Alonso Gustavo , Matvienko Marta , López-Valle Mayra L. , Lázaro-Mixteco Pedro E. , Napsucialy-Mendivil Selene , Dubrovsky Joseph G. , Shishkova Svetlana
Published: May 2018

Many Cactaceae species exhibit determinate growth of the primary root as a consequence of root apical meristem (RAM) exhaustion. The genetic regulation of this growth pattern is unknown. Here, we de novo assembled and annotated the root apex transcriptome of the Pachycereus pringlei primary root at three developmental stages, with active or exhausted RAM. The assembled transcriptome is robust and comprehensive, and was used to infer a transcriptional regulatory network of the primary root apex. Putative orthologues of Arabidopsis regulators of RAM maintenance, as well as putative lineage-specific transcripts were identified. The transcriptome revealed putative orthologues of most proteins involved in housekeeping processes, hormone signalling, and metabolic pathways. Our results suggest that specific transcriptional programs operate in the root apex at specific developmental time points. Moreover, the transcriptional state of the P. pringlei root apex as the RAM becomes exhausted is comparable to the transcriptional state of cells from the meristematic, elongation, and differentiation zones of Arabidopsis roots along the root axis. We suggest that the transcriptional program underlying the drought stress response is induced during Cactaceae root development, and that lineage-specific transcripts could contribute to RAM exhaustion in Cactaceae.
Role of subsurface ocean in decadal climate predictability over the South Atlantic
Authors: Morioka Yushi , Doi Takeshi , Storto Andrea , Masina Simona , Behera Swadhin K.
Published: May 2018

Decadal climate predictability in the South Atlantic is explored by performing reforecast experiments using a coupled general circulation model with two initialization schemes; one is assimilated with observed sea surface temperature (SST) only, and the other is additionally assimilated with observed subsurface ocean temperature and salinity. The South Atlantic is known to undergo decadal variability exhibiting a meridional dipole of SST anomalies through variations in the subtropical high and ocean heat transport. Decadal reforecast experiments in which only the model SST is initialized with the observation do not predict well the observed decadal SST variability in the South Atlantic, while the other experiments in which the model SST and subsurface ocean are initialized with the observation skillfully predict the observed decadal SST variability, particularly in the Southeast Atlantic. In-depth analysis of upper-ocean heat content reveals that a significant improvement of zonal heat transport in the Southeast Atlantic leads to skillful prediction of decadal SST variability there. These results demonstrate potential roles of subsurface ocean assimilation in the skillful prediction of decadal climate variability over the South Atlantic.
Clathrate Hydrates of Greenhouse Gases in the Presence of Natural Amino Acids: Storage, Transportation and Separation Applications
Authors: Prasad Pinnelli S. R. , Sai Kiran Burla
Published: May 2018

Storage of greenhouse gases in the form of gas hydrates is attractive and is being pursued rigorously in recent times. However, slow formation rate and inefficient water to hydrate conversion are the main hindering factors. In this report, we examine the role of two amino acids (0.5 wt%), l-methionine (l-met) and l-phenylalanine (l-phe) on the formation of gas hydrates using methane (CH4), carbon dioxide (CO2) and their mixtures as guest molecules. Experiments are conducted under non-stirred and isochoric configurations. The hydrate conversion efficiency of both amino acids is identical for hydrates formed with CH4 and mixture of (CO2+CH4). However, the hydrate conversion is significantly less in CO2 hydrates in l-phe system. Addition of amino acids to the water dramatically improved the kinetics of hydrate formation and 90% of maximum gas uptake in hydrate phase occurred in less than an hour. The water to hydrate conversion is also very efficient (>85%) in the presence of amino acids. Therefore, the amino acids containing systems are suitable for storing both CH4 and CO2 gases. The gas hydrates were characterised using powder x-ray diffraction (XRD) and Raman spectroscopic measurements. These measurements indicate the formation of sI hydrates and encasing of gas molecules as guests.
Reward-enhanced encoding improves relearning of forgotten associations
Authors: Miendlarzewska Ewa A. , Ciucci Sara , Cannistraci Carlo V. , Bavelier Daphne , Schwartz Sophie
Published: May 2018

Research on human memory has shown that monetary incentives can enhance hippocampal memory consolidation and thereby protect memory traces from forgetting. However, it is not known whether initial reward may facilitate the recovery of already forgotten memories weeks after learning. Here, we investigated the influence of monetary reward on later relearning. Nineteen healthy human participants learned object-location associations, for half of which we offered money. Six weeks later, most of these associations had been forgotten as measured by a test of declarative memory. Yet, relearning in the absence of any reward was faster for the originally rewarded associations. Thus, associative memories encoded in a state of monetary reward motivation may persist in a latent form despite the failure to retrieve them explicitly. Alternatively, such facilitation could be analogous to the renewal effect observed in animal conditioning, whereby a reward-associated cue can reinstate anticipatory arousal, which would in turn modulate relearning. This finding has important implications for learning and education, suggesting that even when learned information is no longer accessible via explicit retrieval, the enduring effects of a past prospect of reward could facilitate its recovery.
High sample throughput genotyping for estimating C-lineage introgression in the dark honeybee: an accurate and cost-effective SNP-based tool
Authors: Henriques Dora , Browne Keith A. , Barnett Mark W. , Parejo Melanie , Kryger Per , Freeman Tom C. , Muñoz Irene , Garnery Lionel , Highet Fiona , Jonhston J. Spencer , McCormack Grace P. , Pinto M. Alice
Published: May 2018

The natural distribution of the honeybee (Apis mellifera L.) has been changed by humans in recent decades to such an extent that the formerly widest-spread European subspecies, Apis mellifera mellifera, is threatened by extinction through introgression from highly divergent commercial strains in large tracts of its range. Conservation efforts for A. m. mellifera are underway in multiple European countries requiring reliable and cost-efficient molecular tools to identify purebred colonies. Here, we developed four ancestry-informative SNP assays for high sample throughput genotyping using the iPLEX Mass Array system. Our customized assays were tested on DNA from individual and pooled, haploid and diploid honeybee samples extracted from different tissues using a diverse range of protocols. The assays had a high genotyping success rate and yielded accurate genotypes. Performance assessed against whole-genome data showed that individual assays behaved well, although the most accurate introgression estimates were obtained for the four assays combined (117 SNPs). The best compromise between accuracy and genotyping costs was achieved when combining two assays (62 SNPs). We provide a ready-to-use cost-effective tool for accurate molecular identification and estimation of introgression levels to more effectively monitor and manage A. m. mellifera conservatories.
Anisotropy dependence of the fluctuation spectroscopy in the critical and gaussian regimes in superconducting NaFe1−xCo
x
As single crystals
Authors: Ahmad D. , Choi W. J. , Sóñora D. , Oh Yoon Seok , Mosqueira J. , Park Tuson , Kwon Yong Seung
Published: May 2018

We investigate thermal fluctuations in terms of diamagnetism and magnetotransport in superconducting NaFe1−xCo
x
As single crystals with different doping levels. Results show that in the case of optimal doped and lightly overdoped (x = 0.03, 0.05) crystals the analysis in the critical as well as in the Gaussian fluctuation regions is consistent with the Ginzburg-Landau 3D fluctuation theory. However, in the case of strongly overdoped samples (x ≥ 0.07) the Ullah-Dorsey scaling of the fluctuation induced magnetoconductivity in the critical region confirms that thermal fluctuations exhibit a 3D anisotropic nature only in a narrow temperature region around T
c
(H). This is consistent with the fact that in these samples the fluctuation effects in the Gaussian region above Tc may be described by the Lawrence-Doniach approach. Our results indicate that the anisotropy of these materials increases significantly with the doping level.
Multiscale understanding of tricalcium silicate hydration reactions
Authors: Cuesta Ana , Zea-Garcia Jesus D. , Londono-Zuluaga Diana , De la Torre Angeles G. , Santacruz Isabel , Vallcorba Oriol , Dapiaggi Monica , Sanfélix Susana G. , Aranda Miguel A. G.
Published: May 2018

Tricalcium silicate, the main constituent of Portland cement, hydrates to produce crystalline calcium hydroxide and calcium-silicate-hydrates (C-S-H) nanocrystalline gel. This hydration reaction is poorly understood at the nanoscale. The understanding of atomic arrangement in nanocrystalline phases is intrinsically complicated and this challenge is exacerbated by the presence of additional crystalline phase(s). Here, we use calorimetry and synchrotron X-ray powder diffraction to quantitatively follow tricalcium silicate hydration process: i) its dissolution, ii) portlandite crystallization and iii) C-S-H gel precipitation. Chiefly, synchrotron pair distribution function (PDF) allows to identify a defective clinotobermorite, Ca11Si9O28(OH)2.8.5H2O, as the nanocrystalline component of C-S-H. Furthermore, PDF analysis also indicates that C-S-H gel contains monolayer calcium hydroxide which is stretched as recently predicted by first principles calculations. These outcomes, plus additional laboratory characterization, yielded a multiscale picture for C-S-H nanocomposite gel which explains the observed densities and Ca/Si atomic ratios at the nano- and meso- scales.
Mitochondrial function is impaired in the skeletal muscle of pre-frail elderly
Authors: Andreux Pénélope A. , van Diemen Marcus P. J. , Heezen Maxime R. , Auwerx Johan , Rinsch Chris , Groeneveld Geert Jan , Singh Anurag
Published: May 2018

Aging is accompanied by a gradual decline in both muscle mass and strength over time, which can eventually lead to pathologies, such as frailty and sarcopenia. While these two conditions are well characterized, further investigation of the early biological signs present in pre-frail elderly is still needed to help identify strategies for preventative therapeutic intervention. The goal of the present clinical study was to evaluate the level of mitochondrial (dys)function in a well-defined population of pre-frail elderly (>60 years of age). Pre-frail elderly were compared with an age-matched population of active elderly. Muscle mitochondrial function was assessed in vivo using phosphorus magnetic resonance spectroscopy (31P-MRS) and a comprehensive set of biological biomarkers were measured ex vivo in vastus lateralis muscle biopsies. In pre-frail subjects, phosphocreatine recovery was impaired and mitochondrial respiratory complex protein and activity levels were significantly lower when compared with active elderly. Analysis of microarray data showed that mitochondrial genes were also significantly down-regulated in muscle of pre-frail compared to active elderly. These results show that mitochondrial impairment is a hallmark of pre-frailty development and the onset of decline in muscle function in the elderly.
Rational Discovery of (+) (S) Abscisic Acid as a Potential Antifungal Agent: a Repurposing Approach
Authors: Khedr Mohammed A. , Massarotti Alberto , Mohamed Maged E.
Published: May 2018

Fungal infections are spreading widely worldwide, and the types of treatment are limited due to the lack of diverse therapeutic agents and their associated side effects and toxicity. The discovery of new antifungal classes is vital and critical. We discovered the antifungal activity of abscisic acid through a rational drug design methodology that included the building of homology models for fungal chorismate mutases and a pharmacophore model derived from a transition state inhibitor. Ligand-based virtual screening resulted in some hits that were filtered using molecular docking and molecular dynamic simulations studies. Both in silico methods and in vitro antifungal assays were used as tools to select and validate the abscisic acid repurposing. Abscisic acid inhibition assays confirmed the inhibitory effect of abscisic acid on chorismate mutase through the inhibition of phenylpyruvate production. The repositioning of abscisic acid, the well-known and naturally occurring plant growth regulator, as a potential antifungal agent because of its suggested action as an inhibitor to several fungal chorismate mutases was the main result of this work.
Motion changes response balance between ON and OFF visual pathways
Authors: Luo-Li Gloria , Mazade Reece , Zaidi Qasim , Alonso Jose-Manuel , Freeman Alan W.
Published: May 2018

Humans are faster at detecting dark than light stationary stimuli, a temporal difference that originates early in the visual pathway. Here we show that this difference reverses when stimuli move, making detection faster for moving lights than darks. Human subjects judged the direction of moving edges and bars, and made faster and more accurate responses for light than for dark stimuli. This light/dark asymmetry is greatest at low speeds and disappears at high speeds. In parallel experiments, we recorded responses in the cat visual cortex for moving bars and again find that responses are faster for light bars than for dark bars moving at low speeds. We show that differences in the luminance-response function between ON and OFF pathways can reproduce these findings, and may explain why ON pathways are used for slow-motion image stabilization in many species.
Control of selectivity in hydrosilane-promoted heterogeneous palladium-catalysed reduction of furfural and aromatic carboxides
Authors: Li Hu , Zhao Wenfeng , Saravanamurugan Shunmugavel , Dai Wenshuai , He Jian , Meier Sebastian , Yang Song , Riisager Anders
Published: May 2018

The production of liquid fuels and fine chemicals often involves multi-step reaction processes with selective hydrogenation as one of the key steps. This step most often depends on high-pressure excess hydrogen gas, fossil resources, and newly prepared metallic catalysts. Here we describe an approach to tune activity and selectivity toward transfer hydrogenation of renewable biomass derivatives over commercially available Pd/C using liquid hydrosilane as hydrogen source. The appropriate control of water-doping content, acid type, reaction temperature, and liquid H− donor dosage permits the selective formation of four different value-added products in high yields (≥90%) from bio-based furfural under mild reaction conditions (15–100 °C). Mechanistic insights into the hydrosilane-mediated cascade reactions of furfural are obtained using isotope labeling. The catalyst is recyclable and can selectively reduce an extensive range of aromatic carbonyl compounds to the corresponding alcohols or hydrocarbons in 83–99% yield, typically at 25–40 °C.
Techno-economic and environmental evaluation of producing chemicals and drop-in aviation biofuelsviaaqueous phase processing
Authors: Olcay Hakan , Malina Robert , Upadhye Aniruddha A. , Hileman James I. , Huber George W. , Barrett Steven R. H.
Published: May 2018

Co-produced chemicals can lower the cost of aviation biofuels, and less carbon-intensive hydrogen is needed to reduce their lifecycle emissions.
A dual ammonia-responsive sponge sensor: preparation, transition mechanism and sensitivity
Authors: Guo Jiahong , Bai Zhiwei , Lyu Yonglei , Wang Jikui , Wang Qiang
Published: May 2018

Yellowish and superhydrophobic ammonia-responsive sponge which fabricated by dipping–coating method changes to purple and superhydrophilic when exposed to ammonia condition.
Rational functionalization of reduced graphene oxide with an imidazole group for the electrochemical sensing of bisphenol A – an endocrine disruptor
Authors: Manna Bhaskar
Published: May 2018

An electrochemical bisphenol A sensor has been developed based on its oxidation catalysed by rationally functionalized reduced graphene oxide.
Ruthenium nanoparticles ligated by cholesterol-derived NHCs and their application in the hydrogenation of arenes
Authors: Rakers Lena , Martínez-Prieto Luis M. , López-Vinasco Angela M. , Philippot Karine , van Leeuwen Piet W. N. M. , Chaudret Bruno , Glorius Frank
Published: May 2018

Herein we present ruthenium nanoparticles (Ru-NPs) stabilized with two rigid NHC ligands derived from cholesterol.
Increased rate of solvent diffusion in a prototypical supramolecular gel measured on the picosecond timescale
Authors: Seydel Tilo , Edkins Robert M. , Jones Christopher D. , Foster Jonathan A. , Bewley Robert , Aguilar Juan A. , Edkins Katharina
Published: May 2018

Solvent diffusion in a prototypical supramolecular gel probed by quasi-elastic neutron scattering on the picosecond timescale is faster than that in the respective bulk solvent.
In situ growth of well-ordered NiFe-MOF-74 on Ni foam by Fe2+ induction as an efficient and stable electrocatalyst for water oxidation
Authors: Xing Jiale , Guo Kailu , Zou Zehua , Cai Minmin , Du Jing , Xu Cailing
Published: May 2018

Uniform and well-ordered NiFe-MOF-74 was in situ grown on Ni foam by Fe2+ induction, exhibiting enhanced activity toward the OER with a very low overpotential of 223 mV at a current density of 10 mA cm−2.
An estrogen receptor targeted ruthenium complex as a two-photon photodynamic therapy agent for breast cancer cells
Authors: Zhao Xueze , Li Mingle , Sun Wen , Fan Jiangli , Du Jianjun , Peng Xiaojun
Published: May 2018

In this study, we reported a tamoxifen modified Ru(ii) polypyridyl complex (Ru-tmxf) as an estrogen receptor (ER) targeted photosensitizer.
Influence of particle viscosity on mass transfer and heterogeneous ozonolysis kinetics in aqueous–sucrose–maleic acid aerosol
Authors: Marshall Frances H. , Berkemeier Thomas , Shiraiwa Manabu , Nandy Lucy , Ohm Peter B. , Dutcher Cari S. , Reid Jonathan P.
Published: May 2018

The ozonolysis kinetics of viscous aerosol particles containing maleic acid are studied. Kinetic fits are constrained by measured particle viscosities.
An investigation on the second-order nonlinear optical response of cationic bipyridine or phenanthroline iridium(iii) complexes bearing cyclometallated 2-phenylpyridines with a triphenylamine substituent
Authors: Hierlinger Claus , Cordes David B. , Slawin Alexandra M. Z. , Colombo Alessia , Dragonetti Claudia , Righetto Stefania , Roberto Dominique , Jacquemin Denis , Zysman-Colman Eli , Guerchais Véronique
Published: May 2018

A novel cationic Ir(iii) complex, characterized by a large NLO response, can be incorporated into a polymeric film leading to a good second-harmonic generation.
Boosting energy harvesting performance in (Ba,Ca)(Ti,Zr)O3 lead-free perovskites through artificial control of intermediate grain size
Authors: Yan Xiaodong , Zheng Mupeng , Sun Shengjun , Zhu Mankang , Hou Yudong
Published: May 2018

In this study, (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCTZ) lead-free ceramics with enhanced energy density were prepared by two-step sintering.
Correction: The side effects of platinum-based chemotherapy drugs: a review for chemists
Authors: Oun Rabbab , Moussa Yvonne E. , Wheate Nial J.
Published: May 2018

Correction for ‘The side effects of platinum-based chemotherapy drugs: a review for chemists’ by Rabbab Oun et al., Dalton Trans., 2018, 47, 6645–6653.
Investigation on the hygroscopicity of oxalic acid and atmospherically relevant oxalate salts under sub- and supersaturated conditions
Authors: Boreddy Suresh K. R. , Kawamura Kimitaka
Published: May 2018

Oxalic acid (OxA) is an end product in the oxidation of many organic compounds, and therefore is ubiquitous in the atmosphere and is often the most abundant organic species in ambient aerosols.
Roles of 2-oxoglutarate oxygenases and isopenicillin N synthase in β-lactam biosynthesis
Authors: Rabe Patrick , Kamps Jos J. A. G. , Schofield Christopher J. , Lohans Christopher T.
Published: May 2018

The 2OG oxygenases and IPNS contribute to the great structural diversity of β-lactam natural products, employing some remarkable mechanisms.
Porous metal–organic frameworks based on 3,6-bis(4-benzoic acid)-N-(4-benzoic acid)carbazole for HPLC separation of small organic molecules
Authors: Chen Dong-Hui , Zhuo Chao , Wen Yue-Hong , Lin Ling , Zhang Yu-Xiao , Hu Sheng-Min , Fu Rui-Biao , Wu Xin-Tao
Published: May 2018

A stable porous MOF with a controllable particle size can be used as an HPLC situational phase for small organic molecule separations.
Conjugated polymer-based carbonaceous films as binder-free carbon electrodes in supercapacitors
Authors: Matsushita Satoshi , Yan Bairu , Matsui Takanori , Kim Je-Deok , Akagi Kazuo
Published: May 2018

A facile preparation method for carbonaceous film electrodes was developed using conjugated polymer films as precursors via a morphology-retaining carbonization process.
Fabrication and characterization of a folic acid-bound 5-fluorouracil loaded quantum dot system for hepatocellular carcinoma targeted therapy
Authors: Shi Xiaoxin , He Dongxiu , Tang Guotao , Tang Qian , Xiong Runde , Ouyang Hu , Yu Cui-yun
Published: May 2018

In the present study, we covalently coupled folic acid (FA) and 5-fluorouracil acetic acid (FUA) on the surface of quantum dots (QDs) to produce a tumor targeting drug delivery system, FA-QDs-FUA.
An amperometric glucose biosensor based on PEDOT nanofibers
Authors: Çetin Merih Zeynep , Camurlu Pinar
Published: May 2018

A low cost, robust approach for the production of glucose biosensors was achievedviasimple electrospinning and chemical vapor polymerization techniques.
Insight into mineralizer modified and tailored scorodite crystal characteristics and leachability for arsenic-rich smelter wastewater stabilization
Authors: Sun Yonggang , Yao Qi , Zhang Xin , Yang Hongling , Li Na , Zhang Zhongshen , Hao Zhengping
Published: May 2018

The addition of appropriate mineralizers is a potentially effective strategy for the control of crystal growth, and could be used in the disposal and stabilization of arsenic-rich non-ferrous effluents.
Magnetic extractant with an Fe3O4@SiO2 core and aqueous ammonia coating for microextraction of petroleum acids
Authors: Zhu Gang-Tian , Liu Fei , He Sheng , He Xiao-Mei , Zhu Shu-Kui , Feng Yu-Qi
Published: May 2018

Custom-made magnetic aqueous ammonia was prepared for rapid and selective extraction of petroleum acids.
Fabrication of gold nanowires in micropatterns using block copolymers
Authors: Kim Ye Chan , Kim So Youn
Published: May 2018

In this work, we introduce a facile method for fabricating well-aligned gold nanowires in a desired microstructure by combining the shear alignment of block copolymer (BCP) cylinders with a conventional lithography process.
Hydrothermal synthesis and characterization of novel yellow pigments based on V5+ doped BiPO4 with high near-infrared reflectance
Authors: Ding Cheng , Han Aijun , Ye Mingquan , Zhang Yu , Yao Lingyun , Yang Jiling
Published: May 2018

A series of new yellow pigments was synthesized (BiP1−xVxO4), coatings colored with synthesized pigments have high NIR solar reflectance.
Investigation of crystal structure, microstructure and low temperature magnetic behavior of Ce4+ and Zn2+ co-doped barium hexaferrites (BaFe12O19)
Authors: Tanwar Khagesh , Gyan Deepankar Sri , Gupta Prashant , Pandey Shukdev , OmParkash OmParkash , Kumar Devendra
Published: May 2018

Preparation of Ce–Zn substituted barium hexaferrites and investigation of their magnetic behavior in low temperature regime (2–300 K).
On how ancillary ligand substitution affects the charge carrier dynamics in dye-sensitized solar cells
Authors: Shahroosvand Hashem , Abaspour Saeid , Pashaei Babak , Bideh Babak Nemati
Published: May 2018

With respect to N3, S3 which contained a phenTz (1,10-phenanthroline 5-tetrazole) ancillary ligand showed outstanding improvements in molar extinction coefficient (ε) as well as increases in power conversion efficiency (PCE) and incident photon-to-electron conversion efficiency (IPCE).
Charge transport in germanium doped phosphorene nanoribbons
Authors: Azizi Maryam , Ghavami Badie
Published: May 2018

New two dimensional structures containing phosphorus and germanium atoms are introduced for nanoelectronic applications.
Low-temperature, simple and efficient preparation of perovskite solar cells using Lewis bases urea and thiourea as additives: stimulating large grain growth and providing a PCE up to 18.8%
Authors: Hsieh Cheng-Ming , Liao Yung-Sheng , Lin Yan-Ru , Chen Chih-Ping , Tsai Cheng-Min , Wei-Guang Diau Eric , Chuang Shih-Ching
Published: May 2018

We demonstrated that urea can be used as an efficient additive for perovskite solar cells with a remarkable performance of 18.8%.
Combining transition metals and transient directing groups for C–H functionalizations
Authors: Bhattacharya Trisha , Pimparkar Sandeep , Maiti Debabrata
Published: May 2018

This review is about the momentous evolution of transient directing group assisted C–H functionalizations promoted by three major second row transition metals.
Visible-light-induced C(sp3)–H activation for a C–C bond forming reaction of 3,4-dihydroquinoxalin-2(1H)-one with nucleophiles using oxygen with a photoredox catalyst or under catalyst-free conditions
Authors: Akula Pavan Sudheer , Hong Bor-Cherng , Lee Gene-Hsiang
Published: May 2018

A convenient photocatalyzed coupling reaction of 4-alkyl-3,4-dihydroquinoxalin-2(1H)-one with a variety of nucleophiles was developed with a household compact fluorescent light. The synthesis of natural product cephalandole A was also demonstrated.
Isobutane/2-butene alkylation catalyzed by Brønsted–Lewis acidic ionic liquids
Authors: Liu Shiwei , Tan Shuang , Bian Bing , Yu Hailong , Wu Qiong , Liu Zhiguo , Yu Fengli , Li Lu , Yu Shitao , Song Xiuyan , Song Zhanqian
Published: May 2018

The alkylation reaction of isobutane with 2-butene to yield C8-alkylates was performed using Brønsted–Lewis acidic ionic liquids (ILs) comprising various metal chlorides (ZnCl2, FeCl2, FeCl3, CuCl2, CuCl, and AlCl3) on the anion.
Tailoring the reducibility and catalytic activity of CuO nanoparticles for low temperature CO oxidation
Authors: Zedan Abdallah F. , Mohamed Assem T. , El-Shall M. Samy , AlQaradawi Siham Y. , AlJaber Amina S.
Published: May 2018

Copper oxide (CuO) nanoparticles of tailored reducibility could be used as inexpensive, efficient and durable catalysts for CO oxidation at low temperature.
Optimized inkjet-printed silver nanoparticle films: theoretical and experimental investigations
Authors: Mypati Sreemannarayana , Dhanushkodi Shankar R. , McLaren Michael , Docoslis Aristides , Peppley Brant A. , Barz Dominik P. J.
Published: May 2018

Systematic study of printing scheme and sintering time and temperature on the conductivity of silver flims on glass.
Diasteroselective multi-component assemblies from dynamic covalent imine condensation and metal-coordination chemistry: mechanism and narcissistic stereochemistry self-sorting
Authors: Badetti Elena , Carmo dos Santos Nadia Alessandra , Scaramuzzo Francesca A. , Bravin Carlo , Wurst Klaus , Licini Giulia , Zonta Cristiano
Published: May 2018

Enantio narcissistic self-assembly is observed in a multi-metallic structure used as stereodynamic probe for CD measurements.
Hydrodynamic interaction induced breakdown of the state properties of active fluids
Authors: Chen Yen-Fu , Wang Zhengjia , Chu Kang-Ching , Chen Hsuan-Yi , Sheng Yu-Jane , Tsao Heng-Kwong
Published: May 2018

The mechanical pressure of active fluids in which swimmers are modeled by soft run-and-tumble spheres is investigated by dissipative particle dynamics simulations.
Interconnected metal oxide CNT fibre hybrid networks for current collector-free asymmetric capacitive deionization
Authors: Santos Cleis , Lado Julio J. , García-Quismondo Enrique , Rodríguez Inés V. , Hospital-Benito Daniel , Palma Jesús , Anderson Marc A. , Vilatela Juan J.
Published: May 2018

A novel current collector-free electrode for capacitive deionization to treat brackish water, with low energy consumption and exceptional desalination properties directly linked to the nanoparticle metal oxide/carbon nanotube fibre network morphology.
Core–shell CuPd@Pd tetrahedra with concave structures and Pd-enriched surface boost formic acid oxidation
Authors: Chen Yifan , Yang Yifan , Fu Gengtao , Xu Lin , Sun Dongmei , Lee Jong-Min , Tang Yawen
Published: May 2018

Concave CuPd@Pd tetrahedra are synthesized via a facile l-proline-mediated strategy, exhibiting remarkably improved electrocatalytic performance for formic acid oxidation.
Zr-MOFs-incorporated thin film nanocomposite Pebax 1657 membranes dip-coated on polymethylpentyne layer for efficient separation of CO2/CH4
Authors: Mozafari Mohammad , Abedini Reza , Rahimpour Ahmad
Published: May 2018

Using thin film nanocomposite (TFN) membranes is an effective method to obtain high CO2/CH4 separation performance as compared to traditional mixed matrix membranes (MMMs).
A Matrixed Speech-in-Noise Test to Discriminate Favorable Listening Conditions by Means of Intelligibility and Response Time Results
Authors: Visentin Chiara , Prodi Nicola
Published: May 2018

Purpose

The primary aim of this study was to develop and examine the potentials of a new speech-in-noise test in discriminating the favorable listening conditions targeted in the acoustical design of communication spaces. The test is based on the recognition and recall of disyllabic word sequences. A secondary aim was to compare the test with current speech-in-noise tests, assessing its benefits and limitations.

Method

Young adults (19–40 years old), self-reporting normal hearing, were presented with the newly developed Words Sequence Test (WST; 16 participants, Experiment 1) and with a consonant confusion test and a sentence recognition test (Experiment 2, 36 participants randomly assigned to the 2 tests). Participants performing the WST were presented with word sequences of different lengths (from 2 up to 6 words). Two listening conditions were selected: (a) no noise and no reverberation, and (b) reverberant, steady-state noise (Speech Transmission Index: 0.47). The tests were presented in a closed-set format; data on the number of words correctly recognized (speech intelligibility, IS) and the response times (RTs) were collected (onset RT, single words' RT).

Results

It was found that a sequence composed of 4 disyllabic words ensured both the full recognition score in quiet conditions and a significant decrease in IS results when noise and reverberation degraded the speech signal. RTs increased with the worsening of the listening conditions and the number of words of the sequence. The greatest onset RT variation was found when using a sequence of 4 words. In the comparison with current speech-in-noise tests, it was found that the WST maximized the IS difference between the selected listening conditions as well as the RT increase.

Conclusions

Overall, the results suggest that the new speech-in-noise test has good potentials in discriminating conditions with near-ceiling accuracy. As compared with current speech-in-noise tests, it appears that the WST with a 4-word sequence allows for a finer mapping of the acoustical design target conditions of public spaces through accuracy and onset RT data.
Characterization of gamma-ray burst prompt emission spectra down to soft X-rays
Authors: Oganesyan G. , Nava L. , Ghirlanda G. , Celotti A.
Published: May 2018

Detection of prompt emission by Swift-XRT provides a unique tool to study how the prompt spectrum of gamma-ray bursts (GRBs) extends down to the soft X-ray band. This energy band is particularly important for prompt emission studies, since it is towards low energies that the observed spectral shape is in disagreement with the synchrotron predictions. Unfortunately, the number of cases where XRT started observing the GRB location during the prompt phase is very limited. In this work, we collect a sample of 34 GRBs and perform joint XRT+BAT spectral analysis of prompt radiation, extending a previous study focused on the 14 brightest cases. Fermi-GBM observations are included in the analysis when available (11 cases), allowing the characterization of prompt spectra from soft X-rays to MeV energies. In 62% of the spectra, the XRT data reveal a hardening of the spectrum, well described by introducing an additional, low-energy power-law segment (with index α1) into the empirical fitting function. The break energy below which the spectrum hardens has values between 3 keV and 22 keV. A second power-law (α2) describes the spectrum between the break energy and the peak energy. The mean values of the photon indices are 〈α1〉 = −0.51 (σ = 0.24) and 〈α2〉 = −1.56 (σ = 0.26). These are consistent, within one σ, with the synchrotron values in fast cooling regime. As a test, if we exclude XRT data from the fits we find typical results: the spectrum below the peak energy is described by a power law with 〈α〉 = −1.15. This shows the relevance of soft X-ray data in revealing prompt emission spectra consistent with synchrotron spectra. Finally, we do not find any correlation between the presence of the X-ray break energy and the flux, fluence, or duration of the prompt emission.
Parsec-scale jets driven by high-mass young stellar objects
Authors: Fedriani R. , Caratti o Garatti A. , Coffey D. , Garcia Lopez R. , Kraus S. , Weigelt G. , Stecklum B. , Ray T. P. , Walmsley C. M.
Published: May 2018

Context. Protostellar jets in high-mass young stellar objects (HMYSOs) play a key role in the understanding of star formation and provide us with an excellent tool to study fundamental properties of HMYSOs.

Aims. We aim at studying the physical and kinematic properties of the near-infrared (NIR) jet of IRAS 13481-6124 from au to parsec scales.

Methods. Our study includes NIR data from the Very Large Telescope instruments SINFONI, CRIRES, and ISAAC. Information about the source and its immediate environment is retrieved with SINFONI. The technique of spectro-astrometry is performed with CRIRES to study the jet on au scales. The parsec-scale jet and its kinematic and dynamic properties are investigated using ISAAC.

Results. The SINFONI spectra in H and K bands are rich in emission lines that are mainly associated with ejection and accretion processes. Spectro-astrometry is applied to the Brγ line, and for the first time, to the Brα line, revealing their jet origin with milliarcsecond-scale photocentre displacements (11−15 au). This allows us to constrain the kinematics of the au-scale jet and to derive its position angle (~216°). ISAAC spectroscopy reveals H2 emission along the parsec-scale jet, which allows us to infer kinematic and dynamic properties of the NIR parsec-scale jet. The mass-loss rate inferred for the NIR jet is Ṁejec ~ 10−4 M⊙ yr−1 and the thrust is Ṗ ~ 10−2 M⊙ yr−1 km s−1, which is roughly constant for the formation history of the young star. A tentative estimate of the ionisation fraction is derived for the massive jet by comparing the radio and NIR mass-loss rates. An ionisation fraction ≲8% is obtained, which means that the bulk of the ejecta is traced by the NIR jet and that the radio jet only delineates a small portion of it.
Detection of 40–48 GHz dust continuum linear polarization towards the Class 0 young stellar object IRAS 16293–2422
Authors: Liu Hauyu Baobab , Hasegawa Yasuhiro , Ching Tao-Chung , Lai Shih-Ping , Hirano Naomi , Rao Ramprasad
Published: May 2018

Aims. The aims of this work are to test the feasibility of observing dust polarization at frequencies lower than 50 GHz, which is the optically thinner part of the modified black body spectrum, and to clarify whether or not the polarization mechanism is identical or similar to that for (sub)millimeter observations.

Methods. We performed the new Karl G. Jansky Very Large Array (JVLA) full polarization observations at 40–48 GHz (6.3–7.5 mm) towards the nearby (d= 147 ± 3.4 pc) Class 0 young stellar object (YSO) IRAS 16293–2422, and compared these with the previous Submillimeter Array (SMA) observations. We observed the quasar J1407+2827, which is weakly polarized and can be used as a leakage term calibrator for <9 GHz observations, to gauge the potential residual polarization leakage after calibration.

Results. We did not detect Stokes Q, U, and V intensities from the observations of J1407+2827, and constrain (3σ) the residual polarization leakage after calibration to be ≲0.3%. Limited by thermal noise, we only detected linear polarization from one of the two binary components of our target source, IRAS 16293–2422 B. The measured polarization percentages range from less than one percent to a few tens of percent. The derived polarization position angles from our observations are in excellent agreement with those detected from the previous observations of the SMA, implying that on the spatial scale we are probing (~50–1000 au), the physical mechanisms for polarizing the continuum emission do not vary significantly over the wavelength range of ~0.88–7.5 mm.

Conclusions. We hypothesize that the observed polarization position angles trace the magnetic field, which converges from large scale to an approximately face-on rotating accretion flow. In this scenario, magnetic field is predominantly poloidal on >100 au scales, and becomes toroidal on smaller scales. However, this interpretation remains uncertain due to the high dust optical depths at the central region of IRAS 16293–2422 B and the uncertain temperature profile. We suggest that dust polarization at wavelengths comparable or longer than 7 mm may still trace interstellar magnetic field. Future sensitive observations of dust polarization in the fully optically thin regime will have paramount importance for unambiguously resolving the magnetic field configuration.
From thermal dissociation to condensation in the atmospheres of ultra hot Jupiters: WASP-121b in context
Authors: Parmentier Vivien , Line Mike R. , Bean Jacob L. , Mansfield Megan , Kreidberg Laura , Lupu Roxana , Visscher Channon , Désert Jean-Michel , Fortney Jonathan J. , Deleuil Magalie , Arcangeli Jacob , Showman Adam P. , Marley Mark S.
Published: May 2018

Context.A new class of exoplanets has emerged: the ultra hot Jupiters, the hottest close-in gas giants. The majority of them have weaker-than-expected spectral features in the 1.1−1.7μm bandpass probed by HST/WFC3 but stronger spectral features at longer wavelengths probed bySpitzer. This led previous authors to puzzling conclusions about the thermal structures and chemical abundances of these planets.

Aims.We investigate how thermal dissociation, ionization, H−opacity, and clouds shape the thermal structures and spectral properties of ultra hot Jupiters.

Methods.We use the SPARC/MITgcm to model the atmospheres of four ultra hot Jupiters and discuss more thoroughly the case of WASP-121b. We expand our findings to the whole population of ultra hot Jupiters through analytical quantification of the thermal dissociation and its influence on the strength of spectral features.

Results.We predict that most molecules are thermally dissociated and alkalies are ionized in the dayside photospheres of ultra hot Jupiters. This includes H2O, TiO, VO, and H2but not CO, which has a stronger molecular bond. The vertical molecular gradient created by the dissociation significantly weakens the spectral features from H2Owhile the 4.5μm CO feature remains unchanged. The water band in the HST/WFC3 bandpass is further weakened by the continuous opacity of the H−ions. Molecules are expected to recombine before reaching the limb, leading to order of magnitude variations of the chemical composition and cloud coverage between the limb and the dayside.

Conclusions.Molecular dissociation provides a qualitative understanding of the lack of strong spectral features of water in the 1−2μm bandpass observed in most ultra hot Jupiters. Quantitatively, our model does not provide a satisfactory match to the WASP-121b emission spectrum. Together with WASP-33b and Kepler-33Ab, they seem the outliers among the population of ultra hot Jupiters, in need of a more thorough understanding.
Meningismus
Authors: Topka Helge
Published: May 2018

Die klinische Prüfung des Meningismus stellt ein wichtiges Element der neurologischen Untersuchung in der Notfallsituation dar. Wenngleich die technische Durchführung keine erheblichen Anforderungen stellt, ist die Interpretation schwieriger. Entgegen weitläufiger Ansicht ist der Meningismus weder sehr sensitiv noch spezifisch für die Meningitis oder eine Subarachnoidalblutung. Die korrekte Interpretation erfordert eine sorgfältige Würdigung von Begleitsymptomen und -befunden.
Immuntherapie mit Checkpoint-Inhibitoren beim lokal fortgeschrittenen und metastasierten Urothelzellkarzinom
Authors: Miller Kurt , Gschwend Jürgen , Merseburger Axel , Retz Margitta , Stenzl Arnulf
Published: May 2018

Checkpoint-Inhibitoren haben in der bislang limitierten Therapie des Urothelzellkarzinoms eine neue Ära eingeleitet. Dies spiegelt sich in der aktuellen S3-Leitlinie zum Harnblasenkarzinom derzeit noch nicht wider. Da es sich bei der Krebsimmuntherapie um ein neues Therapieprinzip handelt, stellen sich gegenwärtig Fragen für den Praxisalltag: Auf welchen Daten beruhen die Zulassungen der einzelnen Wirkstoffe? Wie verändern sich die Therapiealgorithmen? Worauf muss beim Therapiemanagement geachtet werden? Welche Nebenwirkungen können auftreten, wie lassen sie sich erkennen und behandeln? Die vorliegende Publikation verfolgt das Ziel, diese Fragen zu beantworten.
Synthesis of Substituted Indole-3-carboxylates by Iron(II)-Catalyzed Domino Isomerization of 3-Alkyl/aryl-4-aryl-5-methoxyisoxazoles
Authors: Khlebnikov Alexander , Bodunov Vladimir , Galenko Ekaterina , Galenko Alexey , Novikov Mikhail
Published: May 2018

The iron(II)-catalyzed domino isomerization of 3-alkyl/aryl-4-arylisoxazoles provides a selective access to a wide range of structurally diverse highly substituted indole-3-carboxylates. The operational simplicity, high atom efficiency, and the use of stable starting materials and an inexpensive and low-toxicity catalyst are some of the attractive features of this tandem double ring-opening–ring-closure strategy.
Proline-Glycine Dipeptidic Derivatives of Chiral Phosphoramides as Organocatalysts for the Enantiodivergent Aldol Reaction of Aryl Aldehydes and Isatins with Cyclohexanone in the Presence of Water
Authors: Juaristi Eusebio , Cruz-Hernández Carlos , Hernández-González Perla
Published: May 2018

The synthesis of several novel organocatalysts derived from (R)- and (S)-proline-glycine dipeptides and incorporating a chiral phosphoramide fragment was accomplished. These chiral compounds catalyze the enantioselective aldol addition reaction of cyclohexanone to prochiral aryl aldehydes and isatins in the presence of water. These chiral organocatalysts represent some of the few proline-derived compounds capable to catalyze aldol-type addition of cyclohexanone to isatins, a C–C bond forming transformation for which chiral primary amines are usually more successful. Additionally, these phosphoramide-containing catalysts afforded excellent results in the addition of cyclohexanone to aryl aldehydes, as anticipated by the presence of the proline moiety. The present report includes a detailed evaluation of the new multifunctional catalysts that are able to afford either enantiomer of the chiral product by adequate selection of the configuration of the proline residue.
Nickel-Catalyzed Transformation of Aryl 2-Pyridyl Ethers via Cleavage of the Carbon–Oxygen Bond: Synthesis of Mono-α-arylated­ Ketones
Authors: Wang Zhong-Xia , Li Jing
Published: May 2018

The nickel/IPr-catalyzed reaction of aryl 2-pyridyl ethers with propiophenone and acetophenone derivatives via C–OPy bond cleavage is performed in the presence of t-BuOLi to give mono-α-arylated ketones in moderate yields. The method is suitable for electron-rich and electron-poor ethers as well as heteroaryl ethers and tolerates a range of active functional groups.
α-Alkylation of N–C Axially Chiral Quinazolinone Derivatives Bearing Various ortho-Substituted Phenyl Groups: Relation between Diastereoselectivity and the ortho-Substituent
Authors: Kitagawa Osamu , Matsuoka Mizuki , Iida Asumi
Published: May 2018

2-Ethylquinazolin-4-one derivatives bearing various ortho-substituted phenyl groups were revealed to possess a stable C–N axially chiral structure at ambient temperature. The reactions of alkyl halides with the anionic species prepared from these quinazolinones were systematically explored. The α-alkylation reactions proceeded with diastereoselectivities ranging from 1:1 to >50:1, depending upon the steric bulk of the ortho-substituent, to afford products having the elements of axial and central chirality in high yields (85–98%).
Cationic Bismuth Compounds in Organic Synthesis and Catalysis: New Prospects for CH Activation
Authors: Lichtenberg Crispin , Ritschel Benedikt
Published: May 2018

Well-defined cationic bismuth complexes, [Bi(NR2)Ln]+, based on simple, monodentate, monoanionic amide ligands have recently been reported (R = Me, iPr, etc.). The unusual reactivity patterns of these species are highlighted, with a focus on a recently reported double CH activation reaction. Mechanistic aspects and the impact of charge on reactivity are discussed. These results are compared with literature-known strategies in bismuth-mediated CH activations, and their potential implications for future research in the field are outlined.

1 Introduction

2 Bismuth-Mediated CH Activation

3 Cationic Bismuth Complexes

4 Cationic Bismuth Amides for CH Activation

5 Conclusion
One-Pot Synthesis of α-Substituted Acrylates
Authors: Matziari Magdalini , Xie Yixin
Published: May 2018

A simple and efficient synthetic method towards α-substituted acrylic esters has been developed using the Horner–Wadsworth–Emmons (HWE) reaction with HCHO after alkylation of phosphonoacetates in a one-pot reaction. This method allows the smooth introduction of various side-chains, such as natural amino acids and other biologically relevant substituents. The use of mild conditions, inexpensive reagents, short reaction times and simple work-up and purification steps provides an effective and general alternative to cumbersome multistep and low-yielding procedures described to date.