bluuebunny/crossref_metadata_2025_split huggingface dataset:
A General and Air‐tolerant Strategy to Conjugated Polymers within Seconds under Palladium(I) Dimer Catalysis
Authors: Magnin Guillaume , Clifton Jamie , Schoenebeck Franziska 
Published: May 2019

AbstractWhile current M0/MII based polymerization strategies largely focus on fine‐tuning the catalyst, reagents and conditions for each and every monomer, this report discloses a single method that allows access to a variety of different conjugated polymers within seconds at room temperature. Key to this privileged reactivity is an air‐ and moisture stable dinuclear PdI catalyst. The method is operationally simple, robust and tolerant to air.
An Industry in Transition: The Chemical Industry and the Megatrends Driving Its Forthcoming Transformation
Authors: Pagliaro Mario 
Published: May 2019

AbstractSignificant product and process innovation is taking place in the chemical industry. Rather than making bold predictions, this Essay emphasizes that this change, due to impact both main segments of the industry, is driven by societal megatrends concerning the environment, health, and energy which permeate societies on a global scale.
Composition design and properties investigation of BPDA/PDA/TFDB co‐polyimide films with low dielectric permittivity
Authors: Li Xiaolan , Lei Huanyu , Guo Jiacong , Wang Jianhua , Qi Shengli , Tian Guofeng , Wu Dezhen 
Published: May 2019

ABSTRACTAiming at fabricating the polyimide (PI) films with low permittivity and excellent comprehensive properties, 2,2′‐bis‐(trifluoromethyl)‐4,4′‐diaminobiphenyl was incorporated into the polyimide backbone composed of 3,3′,4,4′‐biphenyltetracarboxylic dianhydride andp‐phenylenediamine. The introduction of trifluoromethyl (CF3) groups led to a substantial reduction of the PI's permittivity (3.42–2.96). Meanwhile, as‐prepared co‐PI films showed excellent mechanical performance (217.13–238.20 MPa for strength and 3.49–4.90 GPa for modulus), as well as good thermal stability (high glass transition temperature over 354 °C, whereas low thermal expansion coefficient below 10 ppm/K). Structure–property relationship of the PI samples was further established through molecular simulations (MS), which suggested the crucial effects of polarizability per unit volume (α/Vvdw) and free volume on PI permittivity. The computational results were highly consistent with the experimental findings, meaning that MS technique is of guiding importance in copolymer design. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47989.
Structural Investigations on the Interactions between Cytidine Deaminase Human APOBEC3G and DNA
Authors: Yan Xiaoxuan , Lan Wenxian , Wang Chunxi , Cao Chunyang 
Published: May 2019

AbstractHuman APOBEC3G (A3G) inhibits the replication of human immunodeficiency virus‐1 by deaminating cytidine at the 3′‐end in the target motif 5′‐CCC‐3′ in viral cDNA during reverse transcription. It in vitro deaminates two consecutive cytidines in a 3′‐>5′ order. Although a crystal structure of the A3G catalytic domain (A3G‐CD2) with DNA was reported, it is unknown why residues involved in enzymatic reaction are distributed widely. Here, we introduced an iodine atom into the C‐5 position of cytidine (dC6I) in DNA 5′‐ATTC4C5C6IA7ATT‐3′ (TCCC6I). It switches the deamination sequence preference from CCC to TCC, although small dC6I deamination was observed. Solution structures of A3G‐CD2 in complexes with products DNA TCUC6I and TCUU6I indicate that the substrate DNA binds A3G‐CD2 in TCC and CCC modes. The dC6 deamination correlates with the 4th base type. The CCC mode favours dC6 deamination, while the TCC mode results in dC5 deamination. These studies present an extensive basis to design inhibitors to impede viral evolvability.
Effect of Libidibia ferrea bark and seed in maternal reproductive and biochemical outcomes and fetal anomaly in rats
Authors: Pickler Thaisa B. , Lopes Karina P. , Magalhães Stefani A. , Krueger Clarissa M. A. , Martins Milene M. , Filho Valdir Cechinel , Jozala Angela F. , Grotto Denise , Gerenutti Marli 
Published: May 2019

AbstractBackgroundUnhealthy pregnant women living in underdeveloped regions are usually treated by traditional healers, inadvertent of the potential toxic effects of plant‐derivative substances. Thus, we investigated whether exposure to a hydroalcoholic extract of bark and seed of Libidibia ferrea during pregnancy results in fetotoxicity and maternal toxicity. The main constituents of both extracts were analyzed by High Performance Liquid Chromatography (HPLC).MethodsPregnant rats were divided into three groups: control (C), group exposed to extract of bark (Lfb—1.0 g/kg/day), and group exposed to extract of the seed (Lfs—1.0 g/kg/day). Biochemical parameters, reproductive capacity, morphological effects in the offspring were analyzed.ResultsHPLC fingerprint confirmed the presence of ellagic in both bark and seed extracts, and the absence of detectable concentrations of gallic and catechin. Fetuses exposed to L. ferrea extracts presented shorter mean lengths for head and body sections when compared to those in C and exhibited visceral and skeletal anomalies. Pregnant rats exposed to Lfs extracts show alterations in serum creatinine levels and yield amniotic fluid with abnormal biochemical composition.ConclusionBark or seed extracts of L. ferrea do not exhibit safety level compatible to be used in the gestational period.
Simultaneous determination of eight flavonoids in Sedum sarmentosum Bunge from different areas by UHPLC with triple quadrupole MS/MS
Authors: Jiang Zhitao , Wang Xue , Wang Jianchun , Liu Chundi , Pan Jinhuo 
Published: May 2019

AbstractSedum sarmentosum Bunge (SSB) is a traditional Chinese herbal medicine containing multiple components that has been extensively used clinically to treat chronic viral hepatitis and some inflammatory diseases. Total flavonoids are major pharmacologically active components of SSB. To gain a deeper understanding of SSB resources, we analyzed eight chemical constituents in 33 batches of SSB from 11 regions in China. An accurate, precise and sensitive ultra‐high‐performance liquid chromatography coupled with triple quadrupole electrospray tandem mass spectrometry method was developed for the determination of eight flavonoids in SSB. Under the optimized chromatographic conditions, good separation for the eight target components was obtained on an Agilent Zobax SB C18 (50 × 2.1 mm, 5 μm) column within 4 min. The established methods were validated with good linearity (r ≥ 0.9988), precision (RSD ≤ 2.68%), stability (1.43–3.28%) and repeatability (1.14–2.89%). Moreover, the average recoveries were 95.91–100.68%, and the RSDs were 1.50–3.80%. In addition, the analytical conditions of UPLC–ESI–MS/MS provided better sensitivity with a shorter analysis time when compared with the HPLC–DAD method. Hierarchical clustering analysis and principal component analysis were performed to estimate and classify these samples based on the contents of the eight chemical constituents. This study provided the theoretical basis and scientific evidence for the development and utilization of SSB resources.
Eleven New Triterpenoid Glycosides from the Roots of Ilex asprella
Authors: Huang Xiao‐Jun , Wen Si , Guan Xi‐Feng , Wu Zhen‐Long , Li Man‐Mei , Fan Chun‐Lin , Zhang Qing‐Wen , Chan Ging , Wang Ying , Ye Wen‐Cai 
Published: May 2019

AbstractAsprellosides A‐K, nine new ursane‐type triterpenoid glycosides (1–9), and two new oleanane‐type triterpenoid glycosides (10 and 11), including six rare sulfated triterpenoid glycosides, were isolated from the roots of Ilex asprella. Their structures were determined on the basis of comprehensive spectroscopic analysis and chemical methods. Among these compounds, asprelloside B (2) and asprelloside C (3) are the first examples of triterpenoid glycosides bearing a rare 3,4‐O‐disulfo‐xylopyranosyl residue. All the saponins isolated showed no significant effects against respiratory syncytial virus (RSV) and lipopolysaccharide‐induced nitric oxide production in Raw264.7 macrophages.
Controlling the Optoelectronic Properties of Pyrene by Regioselective Lewis Base‐Directed Electrophilic Aromatic Borylation
Authors: Vanga Mukundam , Lalancette Roger A. , Jäkle Frieder 
Published: May 2019

AbstractGiven that pyrene represents one of the most versatile chromophores, the development of new selective routes for its functionalization and tuning of its emission properties is highly desirable. Pyrene‐based BN Lewis pair (LP)‐functionalized polycyclic aromatic hydrocarbons (PAHs) were prepared by regioselective Lewis base‐directed electrophilic aromatic substitution. The requisite 1,6‐dipyridylpyrene ligands were accessed by Suzuki–Miyaura cross‐coupling of 1,6‐bis(pinacolatoboryl)pyrenes with 2‐bromopyridine derivatives. Subsequent electrophilic borylation with BCl3 in the presence of AlCl3 and 2,6‐di‐tert‐butylpyridine as a hindered base produced the dichloroborane complexes, which were then in situ reacted with diphenyl or diethyl zinc. The presence or absence of alkyl chains in the 3,8‐positions of the pyrene moiety determined the position of the B−C bond formation (2,7 in the non‐K region versus 5,10 in the K region) and thereby also the size of the BN heterocycle (five‐ versus six‐membered). The impact of the regioisomeric borylation on the electrochemical, photophysical and structural properties was investigated and the conclusions supported by theoretical calculations. The rapid synthesis of derivatives that are borylated in the K region also suggests strong potential for the development of pyrene derivatives that are otherwise difficult to access.
A symmetric lattice‐based wideband wide phase range digital phase shifter topology
Authors: Avci Celal , Gunes Ece Olcay , Yarman Binboga Siddik 
Published: May 2019

SummaryIn this paper, a novel digital phase shifter topology that achieves wideband and wide phase range is proposed. Wide frequency band operation is accomplished employing symmetrical all‐pass lattice structures. Compact phase shifter size is obtained utilizing the miniaturized microwave monolithic integrated circuit (MMIC) design implementation technology. Therefore, resulting phase shifter units are suitable for various communication systems such as radar and cellular communication smart antenna arrays. This paper provides complete design equations together with design algorithm for the selected phase shift and the center frequency. Design algorithm is developed on MatLab environment. The proposed phase shifting circuit is implemented employing the commercially available 0.18‐μm silicon CMOS technology. The new phase shifter topology provides 00 to 3600 phase shift range over X‐band, even beyond.
Sex ratio at mating does not modulate age fitness effects in Drosophila melanogaster
Authors: Sultanova Zahida , Carazo Pau 
Published: May 2019

AbstractUnderstanding the effects of male and female age on reproductive success is vital to explain the evolution of life history traits and sex‐specific aging. A general prediction is that pre‐/postmeiotic aging processes will lead to a decline in the pre‐ and postcopulatory abilities of both males and females. However, in as much the sexes have different strategies to optimize their fitness, the decline of reproductive success late in life can be modulated by social context, such as sex ratio, in a sex‐specific manner. In this study, we used Drosophila melanogaster to investigate whether sex ratio at mating modulates age effects on male and female reproductive success. As expected, male and female age caused a decrease in reproductive success across male‐biased and female‐biased social contexts but, contrary to previous findings, social context did not modulate age‐related fitness decline in either of the two sexes. We discuss these results in the light of how sex ratio might modulate pre‐/postcopulatory abilities and the opportunity for inter‐ and intrasexual competition in D. melanogaster, and generally suggest that social context effects on these processes are likely to be species specific.
Cytogeography and chromosomal variation of the endemic East Asian herb Lycoris radiata
Authors: Liu Kun , Meng Weiqi , Zheng Lu , Wang Lida , Zhou Shoubiao 
Published: May 2019

AbstractInformation on the spatial distribution of cytotypes and karyotype variation in plants is critical for studies of the origin and evolution of polyploid complexes. Here, the spatial distribution of cytological races and intraspecific variation in the karyotype of Lycoris radiata, an endemic species to East Asia, is investigated. Conventional karyotype analysis methods were used to determine ploidy level and karyotypical characteristics in 2,420 individuals from 114 populations of L. radiata nearly covering the whole distribution areas in China. Of 114 populations studied, 52 (45.61%), 58 (50.88%), and 4 (3.51%) are diploid, triploid, and mixoploid populations, respectively, with 1,224, 1,195, and 1 individuals being diploid, triploid, and tetraploid, respectively. The triploid possesses a much wider distribution range than the diploid, with the former almost occupying the entire range of this complex species in East Asia and the latter distributing in the middle and east regions of China. Triploids tend to occur at high altitudes, and the relationship between the ploidy and altitude is significantly positive but low (r2 = 0.103, p < 0.01). About 98.6% of examined bulbs have a common karyotype consisting of 22 or 33 acrocentric (A) chromosomes. Some aberrant chromosomes which should be generated from A‐type chromosome have been found including metacentrics (m), small metacentrics (m′), and B‐type chromosome. The results can provide a fundamental cytogeographic data for further studies on the evolutionary origins and adaptive divergences of polyploids, especially the triploid, within L. radiata using molecular and/or ecological methods in the future.
Effects of forest types on leaf functional traits and their interrelationships of Pinus massoniana coniferous and broad‐leaved mixed forests in the subtropical mountain, Southeastern China
Authors: Qin Juan , Shangguan Zhouping 
Published: May 2019

AbstractLeaf functional traits are widely used to detect and explain adaptations that enable plants to live under various environmental conditions. This study aims to determine the difference in leaf functional traits among four forest types of Pinus massoniana coniferous and broad‐leaved mixed forests by leaf morphological, nutrients, and stoichiometric traits in the subtropical mountain, Southeastern China. Our study indicated that the evergreen conifer species of P. massoniana had higher leaf dry matter content (LDMC), leaf C content, C/N and C/P ratios, while the three deciduous broad‐leaved species of L. formosana, Q. tissima, and P. strobilacea had higher specific leaf area (SLA), leaf N, leaf P nutrient contents, and N/P ratio in the three mixed forest types. The results showed that the species of P. massoniana has adapted to the nutrient‐poor environment by increasing their leaf dry matter for higher construction costs thereby reducing water loss and reflects a resource conservation strategy. In contrast, the three species of L. formosana, Q. tissima, and P. strobilacea exhibited an optimized resource acquisition strategy rather than resource conservation strategy in the subtropical mountain of southeastern China. Regarding the four forest types, the three mixed forest types displayed increased plant leaf nutrient contents when compared to the pure P. massoniana forest, especially the P. massoniana–L. formosana mixed forest type (PLM). Overall, variation in leaf functional traits among different forest types may play an adaptive role in the successful survival of plants under diverse environments because leaf functional traits can lead to significant effects on leaf function, especially for their acquisition of nutrients and use of light. The results of this study are beneficial to reveal the changes in plant leaf functional traits at the regional scale, which will provide a foundation for predicting changes in leaf traits and adaptation in the future environment.
Effect of local infiltration with oxytocin on hemodynamic response to surgical incision and postoperative pain in patients having open laparoscopic surgery under general anesthesia
Authors: Zayas‐González Hector , González‐Hernández Abimael , Manzano‐García Alfredo , Hernández‐Rivero Donaciano , García‐Cuevas Marco Antonio , Granados‐Mortera Juan Carlos , Vaca‐Aguirre Liliana , Flores‐Fierro Sergio , Martínez-Lorenzana Guadalupe , Condés‐Lara Miguel 
Published: May 2019

AbstractBackgroundPreemptive analgesia encompasses different perioperative interventions that have the final aim of decreasing postoperative pain and improving recovery. Recently, peripheral analgesic effects of oxytocinergic modulation have been suggested. In this regard, we tested the potential analgesic effects of subcutaneous oxytocin (OT) infiltration in patients submitted to laparoscopic cholecystectomy.MethodsThirty patients with similar general characteristics and medical physical conditions were evaluated. The patients were assigned by simple random selection to one of three groups: (a) OT group (n = 10), which received preincisional subcutaneous OT (4 µg/4 ml saline) in the surgical sites for trocar placements; (b) Lidocaine group (n = 10), which received subcutaneous lidocaine 1% (4 ml) in the surgical sites; and (c) Control group (n = 10), which did not receive any treatment. Then we measured the effect of those treatments on the hemodynamic variations produced as responses to the surgical incisions and trocar insertions (open port placements using the Hasson technique). Moreover, we assessed the intensity of postoperative pain with the visual analogue scale during recovery and 24 hr after surgery.ResultsHemodynamic parameters were stable in both intervention groups (subcutaneous OT and lidocaine) during the surgical incisions and trocar placements, whereas a most likely sympathetic activation due to trocar insertions (open port placements) was not blunted in the placebo group. Furthermore, postoperative pain was diminished in both OT and lidocaine groups when compared to the control group.ConclusionsPreincisional subcutaneous OT administration reduced the hemodynamic response produced by the latter. Furthermore, OT also diminished postoperative pain.
Hydrothermal Syntheses of NiO−GO Nanocomposite on 3D Nickel Foam as a Support for Pt Nanoparticles and its Superior Electrocatalytic Activity towards Methanol Oxidation
Authors: Kamyabi Mohammad Ali , Mohammadian Hoda , Jadali Salma , Moharramnezhad Mohsen 
Published: May 2019

AbstractIn this project, Pt/NiO−GO nanocatalyst is grown on nickel foam (NF) and, its catalytic activity towards electrochemical oxidation of methanol in acidic media is studied. The first step is devoted to the synthesis of NiO−GO support by a hydrothermal method. Then Pt nanoparticles (∼34.3 nm) are electrodeposited on this supporting material. Hydrothermal and electrochemical deposition conditions are optimized. Surface of modified NF was inspected for physical characterization and Chemical composition by some techniques such as field emission scanning electron microscopy (FESEM), energy‐dispersive X‐ray spectra (EDS), and X‐ray diffraction (XRD). In the electrochemical section, the catalytic performance of Pt/NiO−GO/NF towards methanol oxidation is investigated by cyclic voltammetry and chronoamperometry measurements. The electrochemical impedance spectroscopy (EIS) is elected to deliberate charge transfer resistance on the catalyst surface. Mass activity, electrochemical surface area (ECSA) and durability of prepared catalysts are compared with commercial Pt/C. Deliberations prove the superiority of Pt/NiO−GO/NF towards methanol oxidation in acidic media. The Superior quality of synthesized nanocatalyst that is attributed to the synergetic effect of the NiO−GO support material and Pt nanoparticles, indicate that Pt/NiO−GO/NF can be successfully used as the anode in the direct methanol fuel cell (DMFC).
Polyion Detection via All‐solid‐contact Paper‐based Polyion‐sensitive Polymeric Membrane Electrodes
Authors: Ferguson Stephen A. , Meyerhoff Mark E. 
Published: May 2019

AbstractThe first all‐solid‐contact paper‐based single‐use polyion‐sensitive ion‐selective electrodes (ISEs) are described. These polyion‐sensitive ISEs are fabricated using cellulose filter paper coated with a carbon ink conductive layer. A polyanion sensing membrane is cast on a section of the coated paper and the sensor is insulated, resulting in a disposable, single‐use device. Various polyanions are shown to yield large negative potentiometric responses when using these disposable devices for direct polyanion detection. These new sensors are further demonstrated to be useful in indirect polycation detection when polycations (i. e., polyquaterniums (PQs)) are titrated with polyanionic dextran sulfate (DS). Titrations monitored using these paper‐based, all‐solid‐contact devices yield endpoints proportional to the given PQ concentration present in the test sample.
Development of a Surfactant/Platinum Composite for Sensitive Cardio‐selective Beta Blocker Detection and their Theoretical Studies
Authors: Zahid Anum , Bakirhan Nurgul K. , Karadurmuş Leyla , Shah Afzal , Ozkan Sibel A. 
Published: May 2019

AbstractAn electrooxidative behavior of beta‐blocker drug esmolol was thoroughly investigated by using glassy carbon electrode modified with sodium dodecyl sulfate‐based platinum nanoparticles. The designed nanosensor exhibited remarkable electro‐catalytic effect by dramatically boosting the signal of the esmolol as compared to the bare electrode with detection limit up to picomolar. The effects of pH, scan rate, temperature, deposition potential, deposition time, effect of electrolyte and interfering agents were investigated to optimize conditions for getting intense signal of the analyte. Under optimized experimental conditions, a linear calibration plot for esmolol with a detection limit of 60 pM was obtained. The analyte sensing ability of the modified electrode was supported by the application of theoretical studies that showed favorable interaction between sodium dodecyl sulfate/platinum nanoparticles composite and esmolol. In this study, our aim was to developed a nanosensor for the sensitive detection of esmolol by electrochemical assay. We tried a lot of different modification style and modifiers for creating a sensitive nanosensor for esmolol. This nanosensor can be applied to the esmolol in serum sample without using any further separation, evaporation or precipitation steps. Application could apply in serum sample to test accuracy of our sensor and method. The high recovery results were observed in serum study.
Electrochemical Characterization and Voltammetric Determination of Benzoyl Derivatives of Phenobarbital Using Glassy Carbon Electrode
Authors: Mezentseva Olga , Slepchenko Galina , Filimonov Victor , Mikheeva Elena , Arbit Galina 
Published: May 2019

AbstractThe electrochemical behavior of a number of benzoyl barbiturates was studied using a glassy carbon electrode (GCE). The kinetics of the electrode process is determined, the contribution of physical adsorption to the electrochemical process is estimated, and the mechanism of the possible electrochemical reaction is proposed. It is shown that the electrochemical reduction potentials of benzoyl phenobarbital derivatives are determined by the LUMO energies, calculated by the B3LYP 6‐311+G method. It is established that the process is quasi‐reversible, complicated by adverse reactions. The influence of halogen type and its position in the benzoyl residue of the studied substances on the analytical signal is established. The effective values of the dissociation constants of various forms of benzoyl derivatives were calculated using the example of halonal, for which the values 3.16 ⋅ 10−8 and 6.31 ⋅ 10−12, respectively, were found.