bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel algorithms for the synchronization control of nonlinear systems
Authors: Tomei Patrizio , Verrelli Cristiano Maria 
Published: September 2015

SummaryWe show how the design of repetitive learning controls, which typically require perfect knowledge of the period T characterizing the periodic reference signals to be tracked, can be generalized, through the design of novel recursive add‐on period identifiers, to face sufficiently small period uncertainties in synchronization problems. Exponential period identification is achieved so that the asymptotic convergence properties guaranteed by the classical learning controls are preserved. Simulation results concerning multi‐link robot synchronization tasks are included. Copyright © 2015 John Wiley & Sons, Ltd.
Optimized Synthesis of nTiO2 Using Murraya koenigii Leaf Extract and Its Application in iPP–EPDM Blends
Authors: Shimpi Navinchandra G. , Shirole Sharda , Suryawanshi Yogesh , Mishra Satyendra 
Published: September 2015

ABSTRACTThe present study deals with the green synthesis of titanium dioxide nanoparticles (nTiO2) using Murraya koenigii leaf extract without any catalyst, template, and surfactant. Colloidal nTiO2 were synthesized by reacting aqueous titanium(IV) isopropoxide with M. koenigii leaf extract under controlled ultrasound cavitation. This study significantly deals with (i) the concentration of titanium(IV) isopropoxide, (ii) the concentration of M. koenigii leaf extract, (iii) rate and time of reaction, (iv) intensity and pulse rate of ultrasound, which had been investigated and optimized for the controllable size and shape of nTiO2 particles. The size and shape of nTiO2 particle were confirmed by using transmission electron microscopy, whereas the size was calculated from XRD spectra using Scherer's formula. Moreover, the effect of nTiO2 particle on properties of isotactic polypropylene–ethylene propylene diene monomer (iPP–EPDM) blends was studied. The physical properties (mechanical, thermal, and swelling) were found to be improved significantly with increasing amount of loading of nTiO2 particles. This increment in properties was due to uniform dispersion of nTiO2 particles, which can be clearly observed in FE‐SEM.
N‐Heterocyclic‐Carbene‐Catalysed Diastereoselective Vinylogous Mukaiyama/Michael Reaction of 2‐(Trimethylsilyloxy)furan and Enones
Authors: Wang Ying , Du Guang‐Fen , Xing Fen , Huang Kuo‐Wei , Dai Bin , He Lin 
Published: September 2015

AbstractN‐heterocyclic carbenes have been utilised as highly efficient nucleophilic organocatalysts to mediate vinylogous Mukaiyama/Michael reactions of 2‐(trimethylsilyloxy)furan with enones to afford γ‐substituted butenolides in 44–99 % yield with 3:1–32:1 diastereoselectivity.
Redox‐Modulation der PTEN‐Phosphataseaktivität durch Wasserstoffperoxid und Bisperoxidovanadium‐Komplexe
Authors: Lee Chang‐Uk , Hahne Gernot , Hanske Jonas , Bange Tanja , Bier David , Rademacher Christoph , Hennig Sven , Grossmann Tom N. 
Published: September 2015

AbstractPTEN ist eine dualspezifische Protein‐Tyrosin‐Phosphatase. Sie ist einer der zentralen Tumorsuppressoren, weshalb eine genaue Regulierung ihrer Aktivität essenziell für die richtige zelluläre Homöostase ist. Die genauen Auswirkungen der Inhibition von PTEN durch reaktive Sauerstoffspezies (z. B. H2O2) und deren strukturelle Folgen sind bisher wenig verstanden. Wichtige Instrumente für das Studium der Wirkung von PTEN‐Inhibition sind Bisperoxidovanadium(bpV)‐Komplexe, mit dem Potenzial für die Behandlung von Nervenverletzungen oder kardialer Ischämie. Allerdings ist ihr Wirkmechanismus unbekannt, was weitere Optimierungen und therapeutische Anwendungen erschwert. Mithilfe der Proteinkristallographie, Massenspektrometrie und NMR‐Spektroskopie untersuchen wir hier die molekularen Grundlagen der PTEN‐Inhibition durch H2O2 und bpV‐Komplexe. Dabei zeigen wir, dass PTEN in beiden Fällen oxidativ inhibiert wird und sich die gleiche intramolekulare Disulfidbrücke bildet. Dies ermöglicht die Reaktivierung von PTEN unter reduzierenden Bedingungen.
Di‐N‐Methylation of Anti‐Gram‐Positive Aminoglycoside‐Derived Membrane Disruptors Improves Antimicrobial Potency and Broadens Spectrum to Gram‐Negative Bacteria
Authors: Benhamou Raphael I. , Shaul Pazit , Herzog Ido M. , Fridman Micha 
Published: September 2015

AbstractThe effect of di‐N‐methylation of bacterial membrane disruptors derived from aminoglycosides (AGs) on antimicrobial activity is reported. Di‐N‐methylation of cationic amphiphiles derived from several diversely structured AGs resulted in a significant increase in hydrophobicity compared to the parent compounds that improved their interactions with membrane lipids. The modification led to an enhancement in antibacterial activity and a broader antimicrobial spectrum. While the parent compounds were either modestly active or inactive against Gram‐negative pathogens, the corresponding di‐N‐methylated compounds were potent against the tested Gram‐negative as well as Gram‐positive bacterial strains. The reported modification offers a robust strategy for the development of broad‐spectrum membrane‐disrupting antibiotics for topical use.
Manganese(I)‐Catalyzed C–H Aminocarbonylation of Heteroarenes
Authors: Liu Weiping , Bang Jonas , Zhang Yujiao , Ackermann Lutz 
Published: September 2015

AbstractA versatile manganese(I) catalyst was employed in CH aminocarbonylation reactions of heteroarenes with aryl as well as with alkyl isocyanates using a removable directing group approach. Detailed experimental mechanistic studies were suggestive of an organometallic CH manganesation step, followed by a rate‐determining migratory insertion.
Understanding P450‐mediated Bio‐transformations into Epoxide and Phenolic Metabolites
Authors: Tomberg Anna , Pottel Joshua , Liu Zhaomin , Labute Paul , Moitessier Nicolas 
Published: September 2015

AbstractAdverse drug reactions are commonly the result of cytochrome P450 enzymes (CYPs) converting the drugs into reactive metabolites. Thus, information about the CYP bioactivation of drugs would not only provide insight into metabolic stability, but also into the potential toxicity. For example, oxidation of phenyl rings may lead to either toxic epoxides or safer phenols. Herein, we demonstrate that the potential to form reactive metabolites is encoded primarily in the properties of the molecule to be oxidized. While the enzyme positions the molecule inside the binding pocket (selects the site of metabolism), the subsequent reaction is only dependent on the substrate itself. To test this hypothesis, we used this observation as a predictor of drug inherent toxicity. This approach was used to successfully identify the formation of reactive metabolites in over 100 drug molecules. These results provide a new perspective on the impact of functional groups on aromatic oxidation of drugs and their effects on toxicity.
Alkali‐Metal‐Mediated Magnesiations of an N‐Heterocyclic Carbene: Normal, Abnormal, and “Paranormal” Reactivity in a Single Tritopic Molecule
Authors: Martínez‐Martínez Antonio J. , Fuentes M. Ángeles , Hernán‐Gómez Alberto , Hevia Eva , Kennedy Alan R. , Mulvey Robert E. , O'Hara Charles T. 
Published: September 2015

AbstractHerein the sodium alkylmagnesium amide [Na4Mg2(TMP)6(nBu)2] (TMP=2,2,6,6‐tetramethylpiperidide), a template base as its deprotonating action is dictated primarily by its 12 atom ring structure, is studied with the common N‐heterocyclic carbene (NHC) IPr [1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene]. Remarkably, magnesiation of IPr occurs at the para‐position of an aryl substituent, sodiation occurs at the abnormal C4 position, and a dative bond occurs between normal C2 and sodium, all within a 20 atom ring structure accommodating two IPr2−. Studies with different K/Mg and Na/Mg bimetallic bases led to two other magnesiated NHC structures containing two or three IPr− monoanions bound to Mg through abnormal C4 sites. Synergistic in that magnesiation can only work through alkali‐metal mediation, these reactions add magnesium to the small cartel of metals capable of directly metalating a NHC.
CH Oxidation of Ingenanes Enables Potent and Selective Protein Kinase C Isoform Activation
Authors: Jin Yehua , Yeh Chien‐Hung , Kuttruff Christian A. , Jørgensen Lars , Dünstl Georg , Felding Jakob , Natarajan Swaminathan R. , Baran Phil S. 
Published: September 2015

AbstractIngenol derivatives with varying degrees of oxidation were prepared by two‐phase terpene synthesis. This strategy has allowed access to analogues that cannot be prepared by semisynthesis from natural ingenol. Complex ingenanes resulting from divergent CH oxidation of a common intermediate were found to interact with protein kinase C in a manner that correlates well with the oxidation state of the ingenane core. Even though previous work on ingenanes has suggested a strong correlation between potential to activate PKCδ and induction of neutrophil oxidative burst, the current study shows that the potential to activate PKCβII is of key importance while interaction with PKCδ is dispensable. Thus, key modifications of the ingenane core allowed PKC isoform selectivity wherein PKCδ‐driven activation of keratinocytes is strongly reduced or even absent while PKCβII‐driven activation of neutrophils is retained.
Lanthanum histidine with pentaerythritol and zinc stearate as thermal stabilizers for poly(vinyl chloride)
Authors: Li Mei , Duan Cheng , Wang Haiou , Liu Zhaogang , Wang Mitang , Hu Yanhong 
Published: September 2015

ABSTRACTLanthanum histidine [La(His)2·(NO3)·2H2O or La(His)2] was synthesized via the reaction of histidine and lanthanum nitrate, and it was investigated as a stabilizer for poly(vinyl chloride) (PVC). The results show that La(His)2 exhibited a stabilizing effect on PVC as a long‐term stabilizer because it prolonged the stability time of PVC to 76 min, which was about 24 times longer than the stability time of the pure PVC. The stabilizing effect of La(His)2 as a costabilizer with pentaerythritol (Pe) and zinc stearate (ZnSt2) was also studied. The results show that the use of La(His)2 with Pe or Pe/ZnSt2 improved the stability time of PVC. La(His)2/Pe/ZnSt2 provided PVC with a good initial color and long‐term stability, and when it was prepared at mass ratios of 0.8:2.4:0.8 and 1.6:1.6:0.8, the stability times of PVC were improved to 86 and 88 min, respectively. As a nontoxic stabilizer, La(His)2/Pe/ZnSt2 has the potential to replace the toxic stabilizers widely used in PVC manufacturing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42878.
Laccase‐catalyzed synthesis of conducting polyaniline‐lignosulfonate composite
Authors: Zhang Ya , Dong Aixue , Fan Xuerong , Wang Qiang , Zhang Ying , Yu Yuanyuan , Cavaco‐Paulo Artur 
Published: September 2015

ABSTRACTEnzymatic polymerization of aniline was first performed in lignosulfonate (LGS) template system. High‐redox‐potential catalyst laccase, isolated from Aspergillus, was used as a biocatalyst in the synthesis of conducting polyaniline/lignosulfonate (PANI‐ES‐LGS) complex using atmospheric oxygen as the oxidizing agent. The linear templates (LGS), also serving as the dopants, could facilitate the directional alignment of the monomer and improve the solubility of the conducting polymer. The process of the polymerization was monitored using UV‐Vis spectroscopy, by which the conditions for laccase‐catalyzed synthesis of PANI‐ES‐LGS complex were also optimized. The structure characterizations and solubility of the complex were carried out using corresponding characterization techniques respectively. The PANI‐ES‐LGS suspensions obtained was used as coating for cotton with a conventional padder to explore the applications of the complex. The variable optoelectronic properties of the coated cotton were confirmed by cyclic voltammetry and color strength test. The molecular weight changes of LGS treated by laccase were also studied to discuss the mechanism of laccase catalyzed aniline polymerization in LGS template system. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42941.
An efficient thermostable organophosphate hydrolase and its application in pesticide decontamination
Authors: Del Giudice Immacolata , Coppolecchia Rossella , Merone Luigia , Porzio Elena , Carusone Teresa Maria , Mandrich Luigi , Worek Franz , Manco Giuseppe 
Published: September 2015

ABSTRACTIn vitro evolution of enzymes represents a powerful device to evolve new or to improve weak enzymatic functions. In the present work a semi‐rational engineering approach has been used to design an efficient and thermostable organophosphate hydrolase, starting from a lactonase scaffold (SsoPox from Sulfolobus solfataricus). In particular, by in vitro evolution of the SsoPox ancillary promiscuous activity, the triple mutant C258L/I261F/W263A has been obtained which, retaining its inherent stability, showed an enhancement of its hydrolytic activity on paraoxon up to 300‐fold, achieving absolute values of catalytic efficiency up to 105 M−1s−1. The kinetics and structural determinants of this enhanced activity were thoroughly investigated and, in order to evaluate its potential biotechnological applications, the mutant was tested in formulations of different solvents (methanol or ethanol) or detergents (SDS or a commercial soap) for the cleaning of pesticide‐contaminated surfaces. Biotechnol. Bioeng. 2016;113: 724–734. © 2015 Wiley Periodicals, Inc.
Enzymatic pretreatment of low‐grade oils for biodiesel production
Authors: Nordblad Mathias , Pedersen Anders K. , Rancke‐Madsen Anders , Woodley John M. 
Published: September 2015

ABSTRACTThe alkaline process for making biodiesel (fatty acid methyl esters, or FAME) is highly efficient at the transesterification of glycerides. However, its performance is poor when it comes to using oil that contain significant amounts of free fatty acids (FFA). The traditional approach to such feedstocks is to employ acid catalysis, which is slow and requires a large excess of methanol, or to evaporate FFA and convert that in a separate process. An attractive option would be to convert the FFA in oil feedstocks to FAME, before introducing it into the alkaline process. The high selectivity of enzyme catalysis makes it a suitable basis for such a pretreatment process. In this work, we present a characterization of the pretreatment of high‐FFA rapeseed oil using immobilized Candida antarctica lipase B (Novozym 435), focused on the impact of initial FFA and methanol concentration. Based on experimental results, we have identified limitations for the process in terms of FFA concentration in the feedstock and make suggestions for process operation. It was found that, using 5% catalyst and 4% methanol at 35°C, the FFA concentration could be reduced to 0.5% within an hour for feedstock containing up to 15% FFA. Further, the reaction was observed to be under kinetic control, in that the biocatalyst converts FFA (and FAME) at a much higher rate than glyceride substrates. There is thus, both a minimum and a maximum reaction time for the process to achieve the desired concentration of FFA. Finally, an assessment of process stability in a continuous packed bed system indicates that as much as 15 m3 oil could potentially be pretreated by 1 kg of biocatalyst at the given process conditions. Biotechnol. Bioeng. 2016;113: 754–760. © 2015 Wiley Periodicals, Inc.
Chiral Ammonium Aryloxides: Efficient Multipurpose Basic Organocatalysts
Authors: Godemert Jérémy , Oudeyer Sylvain , Levacher Vincent 
Published: September 2015

AbstractThis review summarizes the recent developments in chiral quaternary ammonium aryloxides as flexible organocatalysts that are able to act as both a Brønsted and Lewis base. A particular class of ammonium aryloxides, namely betaines, has emerged as an efficient class of catalysts. The performance of betaines stems mainly from the intramolecular nature of these ammonium ion pairs, leading to highly reactive catalytic species with a high level of organization. The above‐mentioned catalysts have been successfully applied to a wide range of asymmetric chemical transformations, including Mukaiyama aldol reactions, tandem Michael addition/lactonization sequences, trifluoromethylation reactions, aza‐Henry reactions, silyl enolates protonation reactions, and Steglich‐type rearrangements, with a high level of enantioselectivity.
Exploration of the Chiral Recognition of Sugar‐Based Diindolylmethane Receptors: Anion and Receptor Structures
Authors: Granda Jarosław M. , Jurczak Janusz 
Published: September 2015

AbstractIn this study, we have conducted a systematic investigation of the chiral recognition of carboxylic anions by D‐glucuronic acid/diindolylmethane receptors. We investigate the influence of the anion structure on chiral recognition in the diindolylmethane/glucuronic acid‐based receptor 1 a. We found that presence of an additional hydrogen‐bond donor at the α position to the carboxylic function is essential for effective chiral differentiation in these systems. Furthermore, we present a synthetic procedure that allows for the synthesis of sugar‐decorated receptors that possess a modified substituent at the anomeric position. Four new receptors 1 b–e have been synthesized, and their chiral‐discrimination ability toward model carboxylates is studied. The obtained results show that the chiral recognition of these receptors can be fine‐tuned by incorporation of a proper substituent into the receptor structure.
Multiple‐Stimuli Responsive Luminescent Gels Based on Cholesterol Containing Benzothiadiazole Fluorophores
Authors: Sun Huibin , Liu Shujuan , Zhao Qiang , Huang Wei 
Published: September 2015

AbstractTwo new fluorescent organogelators based on cholesterol containing benzothiadiazole group have been designed and synthesized. Three methods for gels preparation have been presented, such as heating‐cooling process, ultrasonic treatment and mixed solvents under room temperature. For both of the gels, their states and emission colors exhibit striking changes upon addition of Hg2+. The gelation properties, structural characteristics and fluorescence of the gels were studied by FT‐IR, UV‐Vis absorption and PL spectra. The underlying mechanism of gelation property was studied by X‐ray diffraction combined with theoretical calculation, and the important role of π‐ π interactions in forming the gels has been proved.
Bromine/para‐Toluenesulfonic Acid‐Catalyzed Synthesis of 3,3‐Bis(indole‐3‐yl)indoline‐2‐(1H)‐ones by Condensing Indoles with Isatins
Authors: Huang Wenzhong , Nang Lingli , Li Xiangguang , Yuan Lin , Ma Yinhai , Liang Deqiang 
Published: September 2015

AbstractUnder the catalysis of only 3 mol% of Br2 at room temperature, indoles reacted
rapidly with isatins to form biologically important 3,3‐bis(indole‐3‐yl)indoline‐2‐(1H)‐ones with high efficiency and
wide substrate scope. Moreover, we demonstrated that p‐toluenesulfonic acid (TsOH) could serve as a surrogate to
catalyze this transformation.
N‐Heterocyclic Carbene‐Catalysed Direct Synthesis of Cyano Esters via Cyanation‐Esterification Reaction of α‐Keto Esters
Authors: Zhang Jie , Wang Ying , Du Guangfen , Gu Cheng‐Zhi , Dai Bin 
Published: September 2015

AbstractThe cyanation‐esterification reaction of α‐keto esters catalysed by N‐heterocyclic carbenes (NHCs) is developed. Under the catalysis of 10 mol% 1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene, aromatic and aliphatic α‐keto esters reacted with ethyl cyanoformate or acetyl cyanide to produce the corresponding cyano esters with a tetrasubstituted carbon center in high yields.
Synthesis and Biological Activity of Novel Furan/Thiophene and Piperazine‐Containing (Bis)1,2,4‐triazole Mannich Bases
Authors: Wang Baolei , Shi Yanxia , Zhan Yizhou , Zhang Liyuan , Zhang Yan , Wang Lizhong , Zhang Xiao , Li Yonghong , Li Zhengming , Li Baoju 
Published: September 2015

AbstractSeries of novel furan/thiophene and piperazine‐containing 1,2,4‐triazole Mannich bases and bis(1,2,4‐triazole) Mannich bases have been conveniently synthesizedviaMannich reaction with triazole Schiff bases, various piperazine derivatives, and formaldehyde as intermediates in good yields. Their structures were characterized by melting points,1H NMR,13C NMR, IR and elemental analysis. The preliminary bioassay showed that most compounds exhibited significantin vitroandin vivofungicidal activity against several test plant fungi. Among 32 new compounds, the trifluoromethyl‐containing compounds showed superior activity than the methyl‐containing ones. Several compounds, such asF8,F9,F10,G5,H7,H8,I3andI4, were comparable with some commercial fungicides against different fungi during the present study and could be further structurally optimized. Meanwhile, several compounds showed good herbicidal activity againstBrassica campestrisat 100 µg/mL and KARI inhibitory activity at 200 µg/mL. However, compounds exhibited poor insecticidal activity against oriental armyworm at 200 µg/mL in the preliminary studies. The research results will provide useful information for the design and discovery of new agrochemicals with novel heterocyclic structures.
Sulfonated Graphene Synthesizedviaa Green Route and Its Capacitive Properties
Authors: Zhou Wen , Han Gaoyi , Xiao Yaoming , Chang Yunzhen , Li Miaoyu , Zhang Yuyu 
Published: September 2015

AbstractAn environmentally friendly approach is presented to synthesize sulfonated reduced graphene oxide (S‐rGO) by usingL‐ascorbic acid (L‐AA) and aryl diazonium salt of sulfanilic acid. The preparation conditions have been optimized in order to obtain isolated and conductive S‐rGO, and the products have been characterized by Ultraviolet‐Visible spectroscopy, Fourier transformed infrared spectroscopy, Raman, X‐ray photoelectron spectroscopy and X‐ray powder diffraction and electrochemical methods. The results show that the S‐rGO sheets possess excellent water‐solubility and high electrical conductivity, which implies that the oxygen‐containing functional groups have been removed and conjugated sp2network has been restored. What's more, the electrochemical measurements reveal that the capacitive performance of the S‐rGO has been improved compared with the graphene oxide (GO) and the reduced graphene oxide (rGO, reduced byL‐AA). The optimum S‐rGO exhibits a specific capacitance of 205 F·g−1and good cycling stability (3.9% decreasing after 10000 cycles), which are better than those for graphene oxide (109 F·g−1and decreasing 6.6% after 10000 cycles) and rGO (139 F·g−1and decreasing 11.3% after 10000 cycling). This approach proves a new route to improve the capacitive properties of rGO.
DBU‐Promoted Trifluoromethylation of Aryl Iodides with Difluoromethyltriphenylphosphonium Bromide
Authors: Wei Yun , Yu Liuying , Lin Jinhong , Zheng Xing , Xiao Jichang 
Published: September 2015

AbstractDBU‐promoted trifluoromethylation of aryl iodides with difluoromethyltriphenylphosphonium bromide (DFPB) in the presence of copper source is described. In this transformation, DBU not only acts as base to deprotonate the difluoromethyl group in DFPB to generate difluoromethylene phosphonium ylide Ph3P+CF2−, but also converts the difluorocarbene generated from ylide Ph3P+CF2− into trifluoromethyl anion, finally resulting in the trifluoromethylation of aryl iodides. The reactions proceeded smoothly to afford expected products in moderate to good yields.