bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photoelectroreduction of Building‐Block Chemicals
Authors: Chen Fengjiao , Cui Wei , Zhang Jie , Wang Yeyun , Zhou Junhua , Hu Yongpan , Li Yanguang , Lee Shuit‐Tong 
Published: April 2017

AbstractConventional photoelectrochemical cells utilize solar energy to drive the chemical conversion of water or CO2 into useful chemical fuels. Such processes are confronted with general challenges, including the low intrinsic activities and inconvenient storage and transportation of their gaseous products. A photoelectrochemical approach is proposed to drive the reductive production of industrial building‐block chemicals and demonstrate that succinic acid and glyoxylic acid can be readily synthesized on Si nanowire array photocathodes free of any cocatalyst and at room temperature. These photocathodes exhibit a positive onset potential, large saturation photocurrent density, high reaction selectivity, and excellent operation durability. They capitalize on the large photovoltage generated from the semiconductor/electrolyte junction to partially offset the required external bias, and thereby make this photoelectrosynthetic approach significantly more sustainable compared to traditional electrosynthesis.
Palladium‐Catalyzed Carbonylation of sec‐ and tert‐Alcohols
Authors: Dong Kaiwu , Sang Rui , Liu Jie , Razzaq Rauf , Franke Robert , Jackstell Ralf , Beller Matthias 
Published: April 2017

AbstractA general palladium‐catalyzed synthesis of linear esters directly from sec‐ and tert‐alcohols is described. Compared to the classic Koch–Haaf reaction, which leads to branched products, this new transformation gives the corresponding linear esters in high yields and selectivity. Key for this protocol is the use of an advanced palladium catalyst system with L2 (pytbpx) as the ligand. A variety of aliphatic and benzylic alcohols can be directly used and the catalyst efficiency for the benchmark reaction is outstanding (turnover number up to 89 000).
Total Synthesis of (−)‐Albocycline
Authors: Chatare Vijay K. , Andrade Rodrigo B. 
Published: April 2017

AbstractThe macrolactone natural product (−)‐albocycline is a promising antibiotic candidate for the treatment of both methicillin resistant Staphylococcus aureus (MRSA) and vancomycin‐resistant strains. Herein we report a concise total synthesis of (−)‐albocycline in 14 steps from commercially available methyl (R)‐3‐hydroxybutyrate. Novel key steps include the highly regio‐ and stereoselective reactions of chiral N‐sulfinyl metallodienamines (NSMDs) with aldehydes and the Davis oxaziridine, in addition to the Horner–Wadsworth–Emmons olefination of N‐sulfinyl imines.
Formation of Silver Nanoparticles by Electron Transfer in Peptides and c‐Cytochromes
Authors: Vasylevskyi Serhii I. , Kracht Sonja , Corcosa Paula , Fromm Katharina M. , Giese Bernd , Füeg Michael 
Published: April 2017

AbstractThe reduction of Ag+ ions to Ag0 atoms is a highly endergonic reaction step, only the aggregation to Agn clusters leads to an exergonic process. These elementary chemical reactions play a decisive role if Ag nanoparticles (AgNPs) are generated by electron transfer (ET) reactions to Ag+ ions. We studied the formation of AgNPs in peptides by photoinduced ET, and in c‐cytochromes by ET from their Fe2+/hemes. Our earlier photoinduced experiments in peptides had demonstrated that histidine prevents AgNP formation. We have now observed that AgNPs can be easily synthesized with less‐efficient Ag+‐binding amino acids, and the rate increases in the order lysine<asparagine<aspartate<serine. The ability of Fe2+/hemes of c‐cytochromes to reduce Ag+ to AgNPs was studied in an enzymatic experiment and with living bacteria Geobacter sulfurreducens (Gs).
Synthesis, characterization and application of nano‐CoAl2O4 as an efficient catalyst in the preparation of hexahydroquinolines
Authors: Khazaei Ardeshir , Jafari‐Ghalebabakhani Leila , Ghaderi Esmaeil , Tavasoli Mahsa , Moosavi‐Zare Ahmad Reza 
Published: April 2017

In this work, nano‐CoAl2O4 was prepared and characterized by FT‐IR, energy dispersive X‐ray analysis (EDX), X‐ray diffraction patterns (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM). Nano‐CoAl2O4 was applied for the synthesis of hexahydroquinoline derivatives by the condensation reaction between ethyl acetoacetate, dimedone and various aldehydes. These reactions were carried out at 80 °C under solvent‐free conditions.
Green synthesis of Ni‐Cu‐Zn ferrite nanoparticles using tragacanth gum and their use as an efficient catalyst for the synthesis of polyhydroquinoline derivatives
Authors: Taghavi Fardood Saeid , Ramazani Ali , Golfar Zahra , Joo Sang Woo 
Published: April 2017

Ni0.35Cu0.25Zn0.4Fe2O4 MNPs were synthesized using tragacanth gum as biotemplate and Metals nitrate as the metal source by the sol–gel method. The sample was characterized by powder X‐ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and energy dispersive X‐ray analysis (EDX). The nanoparticles exhibit ferromagnetic behaviour at room temperature, with a saturation magnetization of 52.76 emu/g and a coercivity of 80.14 Oe. Thereupon, Ni‐Cu‐Zn ferrite nanoparticles as an efficient catalyst was used for the synthesis of polyhydroquinoline derivatives via multi‐component reactions under microwave irradiation. Simple work‐up, mild reaction conditions, short reaction times, use of an economically convenient catalyst, and excellent product yields are the advantageous features of this method. The catalyst could easily be recycled and reused few times without noticeable decrease in catalytic activity.
Mechanical enhancement of zirconia reinforced polyimine nanocomposites
Authors: Zhang Si , Lv Yanting , Li Jiayi , Liang Song , Liu Zhenning 
Published: April 2017

ABSTRACTPolymeric nanocomposites have demonstrated superior performance in recent decades, combining the advantages of polymer and nanoparticle fillers. However, nanocomposites of polyimine, a neoteric thermoset material, have been rarely investigated. Herein, a series of polyimine nanocomposites reinforced by zirconia (ZrO2) have been fabricated by heat‐pressing under mild conditions. The resultant polyimine nanocomposites show significant enhancements on multiple mechanical properties including tensile strength, toughness, bending strength, and impact strength, whereas the optimal amount of ZrO2 particles for the best performance of a specific property varies. Interestingly, the tensile strength and toughness of the polyimine nanocomposites can be simultaneously increased by 40% and 85%, indicating that the nanocomposites exhibit excellent integration of tensile strength and toughness analogous to natural materials. Hence, a facile and cost‐effective approach to enhance mechanical properties of polyimine has been realized for more applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45183.
Poly(4‐vinylphenol)/tetra‐n‐butylammonium iodide: Efficient organocatalytic system for synthesis of cyclic carbonates from CO2 and epoxides
Authors: Wang Xiangyong , Zhao Yingying , Kodama Koichi , Hirose Takuji 
Published: April 2017

ABSTRACTAn efficient polymer‐based catalytic system of poly(4‐vinylphenol) and tetra‐n‐butylammonium iodide was developed for the synthesis of cyclic carbonates from epoxides and CO2. Owing to the synergistic effects of hydroxyl groups and iodide anions, this commercially available and metal‐free system was highly active for the reaction of various terminal epoxides under environmentally benign conditions, at 25 to 60 °C and atmospheric pressure of CO2, without the use of any organic solvents. The catalyst system can be easily separated by adding ether, and its ability was recovered by treating it with 40% CH3CO2H aq. The recyclability was investigated in detail for three substrates, epichlorohydrin, 1,2‐epoxyhexane, and styrene oxide, using 1H nuclear magnetic resonance analysis. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45189.
Adaptive Backstepping Control of Six‐Phase PMSM Using Functional Link Radial Basis Function Network Uncertainty Observer
Authors: Lin Faa‐Jeng , Chen Shih‐Gang , Sun I‐Fan 
Published: April 2017

AbstractAn adaptive backstepping control (ABSC) using a functional link radial basis function network (FLRBFN) uncertainty observer is proposed in this study to construct a high‐performance six‐phase permanent magnet synchronous motor (PMSM) position servo drive system. The dynamic model of a field‐oriented six‐phase PMSM position servo drive is described first. Then, a backstepping control (BSC) system is designed for the tracking of the position reference. Since the lumped uncertainty of the six‐phase PMSM position servo drive system is difficult to obtain in advance, it is very difficult to design an effective BSC for practical applications. Therefore, an ABSC system is designed using an adaptive law to estimate the required lumped uncertainty in the BSC system. To further increase the robustness of the six‐phase PMSM position servo drive, an FLRBFN uncertainty observer is proposed to estimate the lumped uncertainty of the position servo drive. In addition, an online learning algorithm is derived using Lyapunov stability theorem to learn the parameters of the FLRBFN online. Finally, the proposed position control system is implemented in a 32‐bit floating‐point DSP, TMS320F28335. The effectiveness and robustness of the proposed intelligent ABSC system are verified by some experimental results.
Theoretical insights into the effect of pH values on oxidation processes in the emission of firefly luciferin in aqueous solution
Authors: Hiyama Miyabi , Akiyama Hidefumi , Koga Nobuaki 
Published: April 2017

AbstractTo elucidate the emission process of firefly d‐luciferin oxidation across the pH range of 7–9, we identified the emission process by comparison of the potential and free‐energy profiles for the formation of the firefly substrate and emitter, including intermediate molecules such as d‐luciferyl adenylate, 4‐membered dioxetanone, and their deprotonated chemical species. From these relative free energies, it is observed that the oxidation pathway changes from d‐luciferin → deprotonated d‐luciferyl adenylate → deprotonated 4‐membered dioxetanone → oxyluciferin to deprotonated d‐luciferin → deprotonated d‐luciferyl adenylate → deprotonated 4‐membered dioxetanone → oxyluciferin with increasing pH value. This indicates that deprotonation on 6′OH occurs during the formation of dioxetanone at pH 7–8, whereas luciferin in the reactant has a 6′OH‐deprotonated form at pH 9.
Targeting Conformational Activation of CDK2 Kinase
Authors: Pellerano Morgan , Tcherniuk Sergey , Perals Corine , Ngoc Van Thi Nhu , Garcin Elsa , Mahuteau‐Betzer Florence , Teulade‐Fichou Marie‐Paule , Morris May C. 
Published: April 2017

AbstractCyclin‐dependent kinases constitute attractive pharmacological targets for cancer therapeutics, yet inhibitors in clinical trials target the ATP‐binding pocket of the CDK and therefore suffer from limited selectivity and emergence of resistance. The more recent development of allosteric inhibitors targeting conformational plasticity of protein kinases offers promising perspectives for therapeutics. In particular tampering with T‐loop dynamics of CDK2 kinase would provide a selective means of inhibiting this kinase, by preventing its conformational activation. To this aim we engineered a fluorescent biosensor that specifically reports on conformational changes of CDK2 activation loop and is insensitive to ATP or ATP‐competitive inhibitors, which constitutes a highly sensitive probe for identification of selective T‐loop modulators. This biosensor was successfully applied to screen a library of small chemical compounds leading to discovery of a family of quinacridine analogs, which potently inhibit cancer cell proliferation, and promote accumulation of cells in S phase and G2. These compounds bind CDK2/ Cyclin A, inhibit its kinase activity, compete with substrate binding, but not with ATP, and dock onto the T‐loop of CDK2. The best compound also binds CDK4 and CDK4/Cyclin D1, but not CDK1. The strategy we describe opens new doors for the discovery of a new class of allosteric CDK inhibitors for cancer therapeutics.
Carboxymethyl β‐cyclodextrin as chiral selector in capillary electrophoresis: Enantioseparation of 16 basic chiral drugs and its chiral recognition mechanism associated with drugs' structural features
Authors: Fang Linlin , Du Yueying , Hu Xiaoyu , Luo Linda , Guo Xin , Guo Xingjie , Yu Jia 
Published: April 2017

AbstractHerein we present the enantioseparation of 10 cardiovascular agents and six bronchiectasis drugs including propranolol, carteolol, metoprolol, atenolol, pindolol, esmolol, bisoprolol, bevantolol, arotinolol, sotalol, clenbuterol, procaterol, bambuterol, tranterol, salbutamol and terbutaline sulfate using carboxymethyl‐β‐cyclodextrin (CM‐β‐CD) as chiral selector. To our knowledge, there is no literature about using CM‐β‐CD for separating carteolol, esmolol, bisoprolol, bevantolol, arotinolol, procaterol, bambuterol and tranterol. During the course of work, changes in pH, CM‐β‐CD concentration, buffer type and concentration were studied in relation to chiral resolution. Excellent enantiomeric separations were obtained for all 16 compounds, especially for procaterol. An impressive resolution value, up to 17.10, was obtained. In particular, most of them achieved rapid separations within 20 min. Given the fact that enantioseparation results rely on analytes' structural characters, the possible separation mechanisms were discussed. In addition, in order to obtain faster separation for propranolol enantiomers in practical application, the effective length of capillary was innovatively shortened from 45 to 30 cm. After the validation, the method was successfully applied to the enantiomeric purity determination of propranolol in the formulation of drug substances.
Swallowing safety in Parkinson's disease after zona incerta deep brain stimulation
Authors: Sundstedt Stina , Holmén Lina , Rova Elin , Linder Jan , Nordh Erik , Olofsson Katarina 
Published: April 2017

AbstractObjectivesThe objective of this study was to examine swallowing function in patients with Parkinson's disease before and after caudal zona incerta deep brain (cZI DBS) surgery. The aims were to examine the effect of cZI DBS on swallowing safety regarding liquid and solid food, as well as to identify the effect of cZI DBS on body mass index (BMI) and specific items from part II of the Unified Parkinson's Disease Rating Scale (UPDRS).Materials and MethodsThe median age of the 14 patients was 57 years (range 46–71), with a median disease duration of 6 years (range 2–13). The present sample is an extension of a previous report, into which six additional patients have been added. Fiber endoscopic examinations of swallowing function, measures of BMI, and evaluation of UPDRS part II items were made before and 12 months after surgery, with and without activated DBS.ResultsThere were no significant changes due to cZI DBS regarding penetration/aspiration, pharyngeal residue or premature spillage (p > .05). Median BMI increased by +1.1 kg/m2 12 months after surgery (p = .01, r = .50). All reported specific symptoms from the UPDRS part II were slight or mild. A significant improvement regarding handling of utensils was seen 12 months postoperatively (p = .03, r = −.42).ConclusionsCaudal zona incerta DBS was found not to have a negative impact on swallowing safety. A significant increase in postoperative weight was observed, and speech seemed to be slightly negatively affected, whereas handling of utensils was improved with cZI DBS.
Constructive approach for smoke plume animation using turbulent toroidal vortices
Authors: Khorloo Oyundolgor , Altantsetseg Enkhbayar 
Published: April 2017

AbstractIn this paper, we propose an efficient approach for generating plausible smoke animation at interactive rates. Among a wide range of smoke animation approaches, our proposed approach simulates the behavior of gaseous phenomena such as turbulent smoke from a steam locomotive. Our method uses existing techniques for simulating smoke animation based on a particle system and extends them by introducing a simple yet efficient toroidal vortex to describe a more complex and turbulent behavior. The key idea is that vortex flows generated by torus‐type smoke primitives are passively advected in a wind field to describe the turbulent flow of smoke.
Structure‐Based Design of a New Scaffold for Cell‐Penetrating Peptidic Inhibitors of the Histone Demethylase PHF8
Authors: Dorosz Jerzy , Olsen Lars , Seger Signe Teuber , Steinhauer Cornelia , Bouras Giorgos , Helgstrand Charlotte , Wiuf Anders , Gajhede Michael 
Published: April 2017

AbstractThe histone demethylase PHF8 catalyzes demethylation of mono‐ and di‐methylated Lys9 on histone H3 (H3K9me1/2), and is a transcriptional activator involved in the development and cancer. Affinity and specificity of PHF8 towards H3K9me2 is affected by interaction with both the catalytic domain and a PHD reader domain. The latter specifically recognizes tri‐methylated Ly4 on histone H3. A fragment of the histone H3 tail with tri‐methylated Lys4 was used as a template for the structure‐based design of a cyclic, cell‐penetrating peptide that exhibits micromolar binding affinity to PHF8 in biochemical assays. The inhibitor has significantly lower affinity towards KDM2 enzymes (the phylogenetically closest subfamily), and to KDM3 and KDM6 subfamilies. Selectivity is only marginal towards an enzyme from the KDM4 family, which shares histone tail specificity with PHF8. It is a substrate of KDM5B, thus implying that the free N terminus is not part of the KDM5 enzyme substrate recognition machinery. The cyclic peptide's ability to penetrate cells is achieved by incorporation of a sequence derived from HIV Tat. The derived cyclic peptide can be used as a starting compound in the search for potent and selective PHF8 inhibitors.
Scope of the Thermal Ring‐Expansion Reaction of Boroles with Organoazides
Authors: Braunschweig Holger , Celik Mehmet Ali , Dellermann Theresa , Frenking Gernot , Hammond Kai , Hupp Florian , Kelch Hauke , Krummenacher Ivo , Lindl Felix , Mailänder Lisa , Müssig Jonas H. , Ruppert Annika 
Published: April 2017

AbstractElectronic and steric factors have been investigated in the thermal ring expansion of boroles with organic azides, a reaction that provides access to highly arylated 1,2‐azaborinines, BN analogues of benzene. Reactions of a variety of boroles and organic azides demonstrate that the synthetic method is quite general in furnishing 1,2‐azaborinines, but the respective reaction rates reveal a strong dependence on the substituents on the two reactants. The products have been characterized by UV/Vis, electrochemical, NMR, and X‐ray diffraction methods, clarifying their constitutions and highlighting substituent effects on the electronic structure of the 1,2‐azaborinines. Furthermore, analysis of several possible mechanistic pathways for 1,2‐azaborinine formation, as studied by DFT, revealed that a two‐step mechanism involving azide–borole adduct formation and nitrene insertion is favored.
Lanthanide Ions Coupled with Photoinduced Electron Transfer Generate Strong Reduction Potentials from Visible Light
Authors: Meyer Andreas Uwe , Slanina Tomáš , Heckel Alexander , König Burkhard 
Published: April 2017

AbstractMetal ions can have beneficial effects on photoinduced electron transfer. Merging such metal‐ion‐coupled electron transfer (MCET) with consecutive photoinduced electron transfer (conPET) enables the one‐electron reduction of chlorobenzene with blue light in the presence of diisopropylethylamine as an electron donor. The presence of the metal ions extends the substrate scope of the photoredox catalysis to extreme reduction potentials (beyond −3 V vs. SCE).
Rapid Access to Nitrogenous Heterobicycles via RhIII‐Catalyzed Isomerization from Alkynes to Allenes
Authors: Nakamura Itaru , Takeda Keisuke , Sato Yoshinori , Terada Masahiro 
Published: April 2017

AbstractWe show that N‐alkynylnitrones are efficiently converted to nitrogenous heterobicyclic compounds with a nitrogen atom at the bridgehead position by using a RhIII‐catalyst. Our mechanistic studies suggest that the reaction proceeds via an allene intermediate, which is generated in situ through RhIII‐catalyzed isomerization of the alkyne group.
Induction of Axial Chirality in 8‐Arylquinolines through Halogenation Reactions Using Bifunctional Organocatalysts
Authors: Miyaji Ryota , Asano Keisuke , Matsubara Seijiro 
Published: April 2017

AbstractThe enantioselective syntheses of axially chiral heterobiaryls were accomplished through the aromatic electrophilic halogenation of 3‐(quinolin‐8‐yl)phenols with bifunctional organocatalysts that control the molecular conformations during successive halogenations. Axially chiral quinoline derivatives, which have rarely been synthesized in an enantioselective catalytic manner, were afforded in moderate‐to‐good enantioselectivities through bromination, and an analogous protocol also enabled enantioselective iodination. In addition, this catalytic reaction, which allows enantioselective control through the use of mono‐ortho‐substituted substrates, allowed the asymmetric synthesis of 8‐arylquinoline derivatives bearing two different halogen groups in high enantioselectivities.
Cyclization of Ynamide‐Tethered 1,3,8‐Triynes
Authors: Sabbasani Venkata R. , Lee Hyunjin , Xie Peipei , Xia Yuanzhi , Lee Daesung 
Published: April 2017

AbstractA facile thermal cyclization of ynamide‐tethered 1,3,8‐triynes to form a 3,5,6,7‐tetrahydro‐1H‐pyrano[3,4‐c]pyridine skeleton is described. Although the mechanism of this unusual reaction has yet to be defined, the formation of either a strained keteniminium or a biradical intermediate followed by a 1,5‐hydride or ‐hydrogen shift is tentatively proposed as the key elementary steps in the reaction sequence. Appropriate electronic activation at the carbon center donating a hydride or hydrogen is crucial for successful cyclization.
Impact of Acid‐Reducing Agents on the Pharmacokinetics of Palbociclib, a Weak Base With pH‐Dependent Solubility, With Different Food Intake Conditions
Authors: Sun Wan , Klamerus Karen J. , Yuhas Lisa M. , Pawlak Sylvester , Plotka Anna , O'Gorman Melissa , Kirkovsky Leonid , Kosa Maha , Wang Diane 
Published: April 2017

AbstractPalbociclib free base capsule is a weak base drug with highly pH‐dependent solubility. In vitro and in vivo studies evaluated the impact of acid‐reducing agents on exposure of palbociclib and determined whether the impact, if any, can be mitigated by food. A drug‐drug interaction study (study 1) was conducted first under fasted conditions and showed that coadministration of multiple doses of the proton‐pump inhibitor rabeprazole substantially reduced palbociclib mean area under the concentration‐time curve from time 0 to infinity and maximum observed plasma concentration by 62% and 80%, respectively. In vitro assessment suggested that the presence of bile salt mixed micelles to mimic the fed state can significantly enhance the solubility of palbociclib. Subsequently, study 2 was conducted under fed conditions and demonstrated that coadministration of rabeprazole decreased palbociclib maximum observed plasma concentration by 41% but had limited impact on area under the concentration‐time curve from 0 to infinity (13% decrease). This study also showed that the histamine‐2 receptor antagonist famotidine and local antacid with staggered dosing had no impact on palbociclib exposure under fed conditions. Food intake effectively mitigated the impact of acid‐reducing agents on palbociclib exposure. Palbociclib free base capsule should be taken with food, and acid‐reducing agent use does not need to be avoided.