bluuebunny/crossref_metadata_2025_split huggingface dataset:
Controlling Second Coordination Sphere Effects in Luminescent Ruthenium Complexes by Means of External Pressure
Authors: Pannwitz Andrea , Poirier Stéphanie , Bélanger‐Desmarais Nicolas , Prescimone Alessandro , Wenger Oliver S. , Reber Christian 
Published: April 2018

AbstractTwo luminescent heteroleptic RuII complexes with a 2,2′‐biimidazole (biimH2) ligand form doubly hydrogen‐bonded salt bridges to 4‐sulfobenzoate anions in single crystals. The structure of one of these cation‐anion adducts shows that the biimH2 ligand is deprotonated. Its 3MLCT luminescence band does not shift significantly under the influence of an external hydrostatic pressure, a behavior typical for these electronic transitions. In contrast, hydrostatic pressure on the other crystalline cation–anion adduct induces a shift of proton density from the peripheral N−H groups of biimH2 towards benzoate, leading to a pronounced redshift of the 3MLCT luminescence band. Such a significant and pressure‐tunable influence from an interaction in the second coordination sphere is unprecedented in artificial small‐molecule‐based systems.
Responsive Self‐Assembly of Supramolecular Hydrogel Based on Zwitterionic Liquid Asymmetric Gemini Guest
Authors: Wu Aoli , Sun Panpan , Sun Na , Zheng Liqiang 
Published: April 2018

AbstractA low‐molecular‐weight supramolecular hydrogel has been fabricated based on host–guest interactions between β‐cyclodextrin (β‐CD) and an asymmetric gemini zwitterionic liquid (ZIL) containing an azobenzene and bis(trifluoromethanesulfonyl)imide. Reversible sol–gel phase transitions were triggered by light and temperature. The binding stoichiometry, mainly noncovalent interactions in the hydrogel, photo‐ and thermoresponsive mechanisms, and mode of inclusion in the complex were studied in detail by NMR spectroscopy, UV/Vis spectroscopy, isothermal titration calorimetry, and control experiments. Interestingly, the β‐CD in the complex can be photo‐manipulated to shuttle along the guest molecule, accompanied by a change in the circular dichroism signals. Reversible switching of the conductivity accompanies the sol–gel phase transition, which demonstrates the stability of the supramolecular hydrogel and its potential application in multi‐stimuli‐responsive electric sensor materials.
Palladium‐Catalyzed Asymmetric Allylic Alkylations of Colby Pro‐Enolates with MBH Carbonates: Enantioselective Access to Quaternary C−F Oxindoles
Authors: Zhu Yi , Mao Yu , Mei Haibo , Pan Yi , Han Jianlin , Soloshonok Vadim A. , Hayashi Tamio 
Published: April 2018

AbstractOwing to the innovative applications of fluorinated compounds in many areas of technology and medicine, methods for the preparation of C−F quaternary fluorine containing compounds are in extremely high demand. Here, we report the discovery of a general procedure for an SN2 reaction catalyzed by Pd/Ding‐SKP‐type ligands, and that occurs between Colby pro‐enolates with MBH carbonates to afford the corresponding products featuring two consecutive stereogenic carbons, including a C−F quaternary stereogenic center. The reactions readily occur at ambient temperatures with high chemical yields and in excellent chemo‐, diastereo‐ and enantioselective manners. This practically attractive stereochemical outcome, coupled with the operational simplicity and structural generality, bodes well for the synthetic application of this process in the preparation of a novel class of biologically relevant fluorine‐containing compounds.
Ion‐Exchangeable Microporous Polyoxometalate Compounds with Off‐Center Dopants Exhibiting Unconventional Luminescence
Authors: Zhou Dan‐Dan , Zhao Qing , Zhu Fu‐Ping , Zhang Zhi‐Gang , Zhou Yang , Yong Zi‐Jun , Ma Ju‐Ping , Kuroiwa Yoshihiro , Moriyoshi Chikako , Fang Yong‐Zheng , Gu Jia‐Li , Shu Jie , Li Zhi‐Yong , Chen Jian‐Mei , Zheng Li‐Rong , Sun Hong‐Tao 
Published: April 2018

AbstractThe synthesis of luminescent polyoxometalates (POMs) typically relies on the assembly of POM ligands with rare earth or transition metals, placing significant constraints on the composition, structure, and hence the luminescence properties of the resultant systems. Herein, we show that the ion‐exchange strategy can be used for the synthesis of novel POM‐based luminescent materials. We demonstrate that introducing bismuth ions into an ion‐exchangeable, microporous POM compound yields an unconventional system luminescing in the near‐infrared region. Experimental characterization, coupled with quantum chemical calculations, confirms that bismuth ions site‐specifically occupy an off‐center site in the lattice, and have an asymmetric coordination geometry unattainable by other means, thus giving rise to peculiar emission. Our findings offer an effective strategy for the synthesis of POM‐based luminescent materials, and the design concept may potentially be adapted to the creation of POM‐based systems with other functionalities.
Combining ROC curves using MAMSE weighted distributions
Authors: Plante Jean‐François , Débordès Jean‐Baptiste 
Published: April 2018

AbstractThe receiver operating characteristic (ROC) curve can be used to evaluate the properties of a diagnostic test from the distribution of a variable on the healthy and diseased populations. The minimum averaged mean squared error (MAMSE) weights were developed to handle data from different sources by adjusting the relative contribution of each data source. The authors use the MAMSE weights to infer the ROC curve of a diagnostic test based on raw data from multiple studies. The proposed estimates are consistent and Monte Carlo simulations show favourable finite sample performance. The method is illustrated in a case study where progesterone level is used to detect ectopic pregnancies and abortions from other natural causes. The Canadian Journal of Statistics 46: 298–315; 2018 © 2018 Statistical Society of Canada
Long Periodic Structure of a Room‐Temperature Ionic Liquid by High‐Pressure Small‐Angle X‐Ray Scattering and Wide‐Angle X‐Ray Scattering: 1‐Decyl‐3‐Methylimidazolium Chloride
Authors: Abe Hiroshi , Hamaya Nozomu , Koyama Yoshihiro , Kishimura Hiroaki , Takekiyo Takahiro , Yoshimura Yukihiro , Wakabayashi Daisuke , Funamori Nobumasa , Matsuishi Kiyoto 
Published: April 2018

AbstractThe Bragg reflections of 1‐decyl‐3‐methylimidazolium chloride ([C10mim][Cl]), a room‐temperature ionic liquid, are observed in a lowly scattered wavevector (q) region using high‐pressure (HP) small‐angle X‐ray scattering methods. The HP crystal of [C10mim][Cl] was characterized by an extremely long periodic structure. The peak position at the lowest q (1.4 nm−1) was different from that of the prepeak observed in the liquid state (2.3 nm−1). Simultaneously, Bragg reflections at high‐q were detected using HP wide‐angle X‐ray scattering. The longest lattice constant was estimated to be 4.3 nm using structural analysis. The crystal structure of HP differed from that of the low‐temperature (LT) crystal and the LT liquid crystal. With increasing pressure, Bragg reflections in the high‐q component became much broader, and were accompanied by phase transition, although those in the low‐q component were observed to be relatively sharp.
Implementing and Quantifying the Shape‐Memory Effect of Single Polymeric Micro/Nanowires with an Atomic Force Microscope
Authors: Fang Liang , Gould Oliver E. C. , Lysyakova Liudmila , Jiang Yi , Sauter Tilman , Frank Oliver , Becker Tino , Schossig Michael , Kratz Karl , Lendlein Andreas 
Published: April 2018

AbstractThe implementation of shape‐memory effects (SME) in polymeric micro‐ or nano‐objects currently relies on the application of indirect macroscopic manipulation techniques, for example, stretchable molds or phantoms, to ensembles of small objects. Here, we introduce a method capable of the controlled manipulation and SME quantification of individual micro‐ and nano‐objects in analogy to macroscopic thermomechanical test procedures. An atomic force microscope was utilized to address individual electro‐spun poly(ether urethane) (PEU) micro‐ or nanowires freely suspended between two micropillars on a micro‐structured silicon substrate. In this way, programming strains of 10±1% or 21±1% were realized, which could be successfully fixed. An almost complete restoration of the original free‐suspended shape during heating confirmed the excellent shape‐memory performance of the PEU wires. Apparent recovery stresses of σmax,app=1.2±0.1 and 33.3±0.1 MPa were obtained for a single microwire and nanowire, respectively. The universal AFM test platform described here enables the implementation and quantification of a thermomechanically induced function for individual polymeric micro‐ and nanosystems.
Multi‐Scale Responses of Liquid Crystals Triggered by Interfacial Assemblies of Cleavable Homopolymers
Authors: Kim Young‐Ki , Huang Yuran , Tsuei Michael , Wang Xin , Gianneschi Nathan C. , Abbott Nicholas L. 
Published: April 2018

AbstractLiquid crystals (LCs) offer the basis of stimuli‐responsive materials that can amplify targeted molecular events into macroscopic outputs. However, general and versatile design principles are needed to realize the full potential of these materials. To this end, we report the synthesis of two homopolymers with mesogenic side chains that can be cleaved upon exposure to either H2O2(polymerP1) or UV light (polymerP2). Optical measurements reveal that the polymers dissolve in bulk LC and spontaneously assemble at nematic LC‐aqueous interfaces to impose a perpendicular orientation on the LCs. Subsequent addition of H2O2to the aqueous phase or exposure of the LC to UV was shown to trigger a surface‐driven ordering transition to a planar orientation and an accompanying macroscopic optical output. Differences in the dynamics of the response to each stimulus are consistent with sequential processing ofP1at the LC‐aqueous interface (H2O2) and simultaneous transformation ofP2within the LC (UV). The versatility of the approach is demonstrated by creating stimuli‐responsive LCs as films or microdroplets, and by dissolving mixtures ofP1andP2into LCs to create LC materials that respond to two stimuli. Overall, our results validate a simple and generalizable approach to the rational design of polymers that can be used to program stimuli‐responsiveness into LC materials.
Conducting Polymer/Ionic Liquid Composite Modified Carbon Paste Electrode for the Determination of Carbaryl in Real Samples
Authors: Salih Fatima Ezzahra , Oularbi Larbi , Halim El , Elbasri Miloud , Ouarzane Aicha , El Rhazi Mama 
Published: April 2018

AbstractA new method has been described for carbaryl determination using a simple electrochemical sensor. The unique properties of poly‐pPhenylenediamine and ionic liquid were exploited to fabricate carbon paste electrode modified with composite based on conducting polymer/ionic liquid. Electrode surface characterization was performed by electrochemical methods (cyclic voltammetry and electrochemical impedance spectroscopy) and by scanning electron microscopy. Differential pulse voltammetry was employed for the detection of carbaryl in acetate buffer solution. Different parameters affecting the carbaryl response were optimized such as ionic liquid amounts, cycle number of polymerization and monomer concentration, pH, and accumulation time. Under the optimum experimental conditions, a linear response was obtained between 0.5 and 200 μmol/L, with detection limit of 0.09 μmol/L. The developed sensor offered satisfactory results for carbaryl detection in spring water and fruit samples.
Microchip electrophoresis separation of a panel of preterm birth biomarkers
Authors: Nielsen Anna V. , Nielsen Jacob B. , Sonker Mukul , Knob Radim , Sahore Vishal , Woolley Adam T. 
Published: April 2018

AbstractPreterm birth (PTB) is responsible for over one million infant deaths annually worldwide. Often, the first and only indication of PTB risk is the onset of early labor. Thus, there is an urgent need for an early PTB risk diagnostic that is inexpensive, reliable, and robust. Here, we describe the development of a microchip electrophoresis (μCE) method for separating a mixture of six PTB protein and peptide biomarkers present in maternal blood serum. μCE devices were photografted with a poly(ethylene glycol) diacrylate surface coating to regulate EOF and reduce nonspecific analyte adsorption. Separation conditions including buffer pH, buffer concentration, and applied electric field were varied to improve biomarker peak resolution while minimizing deleterious effects like Joule heating. In this way, it was possible to separate six PTB biomarkers, the first μCE separation of this biomarker panel. LODs were also measured for each of the six PTB biomarkers. In the future, this μCE separation can be integrated with upstream maternal blood serum sample preparation steps to yield a complete PTB risk diagnosis microdevice.
An enhanced bioindicator for calorimetric monitoring of prophage‐activating chemicals in the trace concentration range
Authors: Xu Juan , Jiang Feng‐Lei , Liu Yi , Kiesel Bärbel , Maskow Thomas 
Published: April 2018

AbstractViruses that infect bacteria (bacteriophages) can either lyse bacteria directly or integrate their genome into the bacterial genome. In the latter case, the viral genome (called prophage) remains dormant, and both phages and bacteria are able to survive in this state. But the silent prophages can be reactivated by, e.g., chemicals, accompanied by the release of substantial quantities of phage particles that further infect other phage‐sensitive bacteria, thus harming ecosystems or technical systems by way of a viral bloom. Recently, a calorimetric method was developed to monitor the prophage‐activating properties of chemicals. The method evaluates the difference in the metabolic heat of the Escherichia coli bioindicator with (λ+) and without (λ−) lambda prophages under the influence of the test substances. Simulations and experiments clearly demonstrate that the sensitivity of the test can be significantly improved, when a customized mixture of λ+ and λ− E. coli strains is used for enhanced bioindication. Hence, the new method mirrors a common situation in nature, where bacteria with and without prophages coexist. In summary, a monitoring method is suggested that provides quick results (after few hours) and offers both the option for automation with low workload (requires only a few minutes) and usage of commercially available instruments.
Suppressing the Voltage Decay and Enhancing the Electrochemical Performance of Li1.2Mn0.54Co0.13Ni0.13O2 by Multifunctional Nb2O5 Coating
Authors: Pan Wei , Peng Wenjie , Yan Guochun , Guo Huajun , Wang Zhixing , Li Xinhai , Gui Weihua , Wang Jiexi , Chen Ning 
Published: April 2018

AbstractThis study focuses on suppressing the voltage decay and improving the electrochemical performance of Li‐rich and manganese‐based (LRM) material by Nb2O5 coating, which is realized by an effective soft‐chemical route using a mixture of ethanol and water as co‐solvent. After Nb2O5 coating, the resulted material demonstrates superior electrochemical performance as cathode material for LIBs. Particularly, it shows an excellent capacity retention of 98 % after 200 cycles at 1 C (1 C=250 mA g−1). Voltage decay within cycling is also obviously suppressed by Nb2O5 coating. Moreover, it exhibits superior rate capacities, delivering 189 and 152 mAh g−1 at high current densities of 2 and 5 C, respectively. The improved electrochemical performance of Nb2O5 coated sample can be attributed to that Nb2O5 can suppress the phase transformation and voltage decay by acting as not only a fast ion conductor to accelerate the lithium ion diffusion at the cathode/electrolyte interface, but also an inert protective layer to reduce the direct contact between the cathode and electrolyte.
Signal strength and spectral efficiency in heterogeneous ultradense networks
Authors: Liu Qiaoshou , Zhang Zhongpei , Shi Jiangpan 
Published: April 2018

AbstractTo meet the rapid data growth requirements of mobile users, heterogeneous ultradense networks improve the spatial reuse efficiency of spectrum resources through the ultradense deployment of small base stations (SBSs) in a given area in the forthcoming fifth‐generation mobile communication networks. It has become one of research hotspots that solve this problem in the recent years. Using the stochastic geometry, the cumulative distribution function and the probability density function of distance from user to its kth closest SBS are derived in this paper. Furthermore, the means of received signal strength from the users' kth closest base station and the mean of signal‐to‐interference‐plus‐noise ratio are derived. The expression of the relationship between spectral efficiency and the density of the SBSs is presented. Finally, The results show that the signal‐to‐interference‐plus‐noise ratio is inversely proportional to the density of SBSs in the 1‐tier ultradense networks. In the 2‐tier heterogeneous ultradense networks, the spectral efficiency of the base station increases first and then decreases with the increasing of the density of SBSs. Moreover, allocating more spectrum resource to SBSs will increase the area spectral efficiency when the number of SBS is far more than the number of macro base stations.
A hierarchical clustering method for dimension reduction in joint analysis of multiple phenotypes
Authors: Liang Xiaoyu , Sha Qiuying , Rho Yeonwoo , Zhang Shuanglin 
Published: April 2018

ABSTRACTGenome‐wide association studies (GWAS) have become a very effective research tool to identify genetic variants of underlying various complex diseases. In spite of the success of GWAS in identifying thousands of reproducible associations between genetic variants and complex disease, in general, the association between genetic variants and a single phenotype is usually weak. It is increasingly recognized that joint analysis of multiple phenotypes can be potentially more powerful than the univariate analysis, and can shed new light on underlying biological mechanisms of complex diseases. In this paper, we develop a novel variable reduction method using hierarchical clustering method (HCM) for joint analysis of multiple phenotypes in association studies. The proposed method involves two steps. The first step applies a dimension reduction technique by using a representative phenotype for each cluster of phenotypes. Then, existing methods are used in the second step to test the association between genetic variants and the representative phenotypes rather than the individual phenotypes. We perform extensive simulation studies to compare the powers of multivariate analysis of variance (MANOVA), joint model of multiple phenotypes (MultiPhen), and trait‐based association test that uses extended simes procedure (TATES) using HCM with those of without using HCM. Our simulation studies show that using HCM is more powerful than without using HCM in most scenarios. We also illustrate the usefulness of using HCM by analyzing a whole‐genome genotyping data from a lung function study.
Late Carboniferous adakitic porphyries in the Huangliangzi pluton, West Junggar (Xinjiang), NW China: Petrogenesis and their tectonic implications
Authors: Duan Fenghao , Li Yongjun , Yang Gaoxue , Zhi Qian , Li Yuhang , Tao XiaoYang , Gao JunBao , Chen RongGuang 
Published: April 2018

Late Carboniferous to Early Permian granitic rocks are widely distributed in the Western Junggar (Xinjiang, NW China), but their petrogenesis and tectonic contexts remain controversial. In this paper, we present new zircon U–Pb age, major element, trace element data for the Huangliangzi pluton from the southern West Junggar. The pluton mainly consists of granodiorite porphyry, biotite monzonitic granite porphyry, and quartz monzonite diorite porphyry. Laser‐ablation inductively‐coupled mass‐spectrometry (LA‐ICP‐MS) zircon U–Pb obtained the age of 321.7 ± 1.3 Ma, indicating the granodiorite porphyry was emplaced in the early Late Carboniferous, coeval with abundant magmatic rocks in the region. Geochemically, these rocks are moderately peraluminous high‐K calc‐alkalic and characterized by relatively high SiO2 (64.31–66.69 wt.%), Al2O3 (15.82–16.73 wt.%), and Sr (379–489 ppm) contents and low MgO (1.08–2.46 wt.%; Mg# = 39–55), Y (7.61–9.64 ppm), and Yb (0.95–1.23 ppm) contents, along with positive Eu anomalies (Eu/Eu* = 1.01–1.34) and high Sr/Y (47.7–57.1) ratios. These are compositional features of adakites that are commonly assumed to have been produced through partial melting of subducted oceanic crust. In addition, the adakitic rocks are relatively enriched in light rare‐earth elements (LREEs), large ion lithophile elements (LILEs: e.g., Rb, Ba, Sr, and K), and depleted in high‐field‐strength elements (HFSEs: e.g., Nb, Ta, and Ti) and are also characterized by high εNd(t) value and low initial (87Sr/86Sr)i ratio. The most plausible mechanism for the Huangliangzi adakitic porphyries is the partial melting of subducted oceanic crust interacting with a mantle wedge. Combined with the geological setting and previous studies, therefore, we suggest that the southern West Junggar was in a subduction‐dominated island‐arc setting in the early Late Carboniferous, and multistage subduction–accretionary orogeny may be the main mechanism for the difference between the north and the south subduction duration in the Western Junggar.
External laryngeal nerve landmarks revisited
Authors: Ortega Consuelo , Maranillo Eva , McHanwell Steve , Sañudo Jose , Vázquez‐Osorio Teresa 
Published: April 2018

ABSTRACTBackgroundBecause external laryngeal nerve (ELN) iatrogenic damage is frequent during neck surgery, its precise localization has been highly recommended. This study analyzes the different surgical landmarks previously proposed and the anatomy of the collateral and terminal branches of the ELN.MethodsThe necks of 157 (77 men and 80 women) human adult embalmed cadavers were examined. The ELN origin, length, and relationship to different landmarks were recorded and results statistically compared with those previously reported.ResultsThe ELN is located deep to the ascending pharyngeal vein in 100% of patients. In most patients, it crosses the carotid axis at the thyroid artery origin level (47% of patients), passes medial to it (89% of patients), and shows an intramuscular trajectory through the inferior constrictor of the pharynx (80% of patients).ConclusionThe ELN position, in relation to classical landmarks, is highly variable. The most reliable relationships are those with the ascending pharyngeal vein or with the superior thyroid artery.