bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalytic Zinc Complexes for Phosphate Diester Hydrolysis
Authors: Tirel Emmanuel Y. , Bellamy Zoë , Adams Harry , Lebrun Vincent , Duarte Fernanda , Williams Nicholas H. 
Published: June 2014

AbstractCreating efficient artificial catalysts that can compete with biocatalysis has been an enduring challenge which has yet to be met. Reported herein is the synthesis and characterization of a series of zinc complexes designed to catalyze the hydrolysis of phosphate diesters. By introducing a hydrated aldehyde into the ligand we achieve turnover for DNA‐like substrates which, combined with ligand methylation, increases reactivity by two orders of magnitude. In contrast to current orthodoxy and mechanistic explanations, we propose a mechanism where the nucleophile is not coordinated to the metal ion, but involves a tautomer with a more effective Lewis acid and more reactive nucleophile. This data suggests a new strategy for creating more efficient metal ion based catalysts, and highlights a possible mode of action for metalloenzymes.
Maximum Noble‐Metal Efficiency in Catalytic Materials: Atomically Dispersed Surface Platinum
Authors: Bruix Albert , Lykhach Yaroslava , Matolínová Iva , Neitzel Armin , Skála Tomáš , Tsud Nataliya , Vorokhta Mykhailo , Stetsovych Vitalii , Ševčíková Klára , Mysliveček Josef , Fiala Roman , Václavů Michal , Prince Kevin C. , Bruyère Stéphanie , Potin Valérie , Illas Francesc , Matolín Vladimír , Libuda Jörg , Neyman Konstantin M. 
Published: June 2014

AbstractPlatinum is the most versatile element in catalysis, but it is rare and its high price limits large‐scale applications, for example in fuel‐cell technology. Still, conventional catalysts use only a small fraction of the Pt content, that is, those atoms located at the catalyst’s surface. To maximize the noble‐metal efficiency, the precious metal should be atomically dispersed and exclusively located within the outermost surface layer of the material. Such atomically dispersed Pt surface species can indeed be prepared with exceptionally high stability. Using DFT calculations we identify a specific structural element, a ceria “nanopocket”, which binds Pt2+ so strongly that it withstands sintering and bulk diffusion. On model catalysts we experimentally confirm the theoretically predicted stability, and on real Pt‐CeO2 nanocomposites showing high Pt efficiency in fuel‐cell catalysis we also identify these anchoring sites.
Palladium‐Catalyzed Direct C2 Arylation of N‐Substituted Indoles with 1‐Aryltriazenes
Authors: Liu Can , Miao Tao , Zhang Lei , Li Pinhua , Zhang Yicheng , Wang Lei 
Published: June 2014

AbstractA novel and efficient palladium‐catalyzed C2 arylation of N‐substituted indoles with 1‐aryltriazenes for the synthesis of 2‐arylindoles was developed. In the presence of BF3⋅OEt2 and palladium(II) acetate (Pd(OAc)2), N‐substituted indoles reacted with 1‐aryltriazenes in N,N‐dimethylacetamide (DMAC) to afford the corresponding aryl–indole‐type products in good to excellent yields.
Unprecedented Cobalt‐Catalyzed Isomerization Reactions to Single Skipped 2,4,7‐Trienes Applied in the Synthesis of Urushiol
Authors: Schmidt Anastasia , Hilt Gerhard 
Published: June 2014

AbstractThe cobalt‐catalyzed isomerization of 1,3‐dienes to 2Z,4E‐dienes was realized for the very challenging substrates with an additional double bond in the side chain. An isomerization to the conjugated 3,5,7‐triene derivative was not observed, which is in stark contrast to observations with many other isomerization catalysts. Accordingly, the synthesis of the natural product urushiol, which has a sensitive 2Z,4E,7Z‐triene subunit in the side chain, was investigated. The O‐protected urushiol derivative was generated selectively without isomerization to the conjugated 3,5,7‐triene or Z/E‐isomerization of the double bond at position 7.
Interaction between the SLC19A1 gene and maternal first trimester fever on offspring neural tube defects
Authors: Pei Lijun , Zhu Huiping , Ye Rongwei , Wu Jilei , Liu Jianmeng , Ren Aiguo , Li Zhiwen , Zheng Xiaoying 
Published: June 2014

BackgroundMany studies have indicated that the reduced folate carrier gene (SLC19A1) is associated with an increased risk of neural tube defects (NTDs). However, the interaction between the SLC19A1 gene variant and maternal fever exposure and NTD risk remains unknown. The aim of this study was to investigate whether the risk for NTDs was influenced by the interactions between the SLC19A1 (rs1051266) variant and maternal first trimester fever.MethodsWe investigated the potential interaction between maternal first trimester fever and maternal or offspring SLC19A1 polymorphism through a population‐based case–control study. One hundred and four nuclear families with NTDs and 100 control families with nonmal newborns were included in the study. SLC19A1 polymorphism was determined using polymerase chain reaction–restricted fragment length polymorphism.ResultsMothers who had the GG/GA genotype and first trimester fever had an elevated risk of NTDs (adjusted odds ratio, 11.73; 95% confidence interval, 3.02–45.58) as compared to absence of maternal first trimester fever and AA genotype after adjusting for maternal education, paternal education, and age, and had a significant interactive coefficient (γ = 3.17) between maternal GG/GA genotype and first trimester fever. However, there was no interaction between offspring's GG/GA genotype and maternal first trimester fever (the interactive coefficient γ = 0.97) after adjusting for confounding factors.ConclusionOur findings suggested that the risk of NTDs was potentially influenced by a gene–environment interaction between maternal SLC19A1 rs1051266 GG/GA genotype and first trimester fever. Maternal GG/GA genotype may strengthen the effect of maternal fever exposure on NTD risk in this Chinese population. Birth Defects Research (Part A) 103:3–11, 2015. © 2014 Wiley Periodicals, Inc.
A novel method for simulating insulin mediated GLUT4 translocation
Authors: Jezewski Andrew J. , Larson Joshua J. , Wysocki Beata , Davis Paul H. , Wysocki Tadeusz 
Published: June 2014

ABSTRACTGlucose transport in humans is a vital process which is tightly regulated by the endocrine system. Specifically, the insulin hormone triggers a cascade of intracellular signals in target cells mediating the uptake of glucose. Insulin signaling triggers cellular relocalization of the glucose transporter protein GLUT4 to the cell surface, which is primarily responsible for regulated glucose import. Pathology associated with the disruption of this pathway can lead to metabolic disorders, such as type II diabetes mellitus, characterized by the failure of cells to appropriately uptake glucose from the blood. We describe a novel simulation tool of the insulin intracellular response, incorporating the latest findings regarding As160 and GEF interactions. The simulation tool differs from previous computational approaches which employ algebraic or differential equations; instead, the tool incorporates statistical variations of kinetic constants and initial molecular concentrations which more accurately mimic the intracellular environment. Using this approach, we successfully recapitulate observed in vitro insulin responses, plus the effects of Wortmannin‐like inhibition of the pathway. The developed tool provides insight into transient changes in molecule concentrations throughout the insulin signaling pathway, and may be employed to identify or evaluate potentially critical components of this pathway, including those associated with insulin resistance. In the future, this highly tractable platform may be useful for simulating other complex cell signaling pathways. Biotechnol. Bioeng. 2014;111: 2454–2465. © 2014 Wiley Periodicals, Inc.
Jasmonsäure – ein universelles Pflanzenhormon
Authors: Wasternack Claus , Hause Bettina 
Published: June 2014

AbstractPflanzen müssen gegen vielfältige biotische und abiotische Umwelteinflusse eine Abwehr aufbauen. Aber gleichzeitig müssen sie wachsen und sich vermehren. Jasmonate sind neben anderen Hormonen ein zentrales Signal bei der Etablierung von Abwehrmechanismen, aber auch Signal von Entwicklungsprozessen wie Blüten‐ und Trichombildung, sowie der Hemmung von Wachstum. Biosynthese und essentielle Komponenten der Signaltransduktion von JA und seinem biologisch aktiven Konjugat JA‐Ile sind gut untersucht. Der Rezeptor ist ein Proteinkomplex, der “JA‐Ile‐Wahrnehmung” mit proteasomalem Abbau von Repressorproteinen verbindet. Dadurch können positiv agierende Transkriptionsfaktoren wirksam werden und vielfältige Genexpressionsänderungen auslösen. Dies betrifft die Bildung von Abwehrproteinen, Enzymen der JA‐Biosynthese und Sekundärstoffbildung, und Proteinen von Signalketten und Entwicklungsprozessen. Die Kenntnisse zur JA‐Ile‐Wirkung werden in Landwirtschaft und Biotechnologie genutzt.
Discovery of Protein Disulfide Isomerase P5 Inhibitors that Reduce the Secretion of MICA from Cancer Cells
Authors: Horibe Tomohisa , Torisawa Aya , Okuno Yukiko , Kawakami Koji 
Published: June 2014

AbstractIn order to regulate the activity of P5, which is a member of the protein disulfide isomerase family, we screened a chemical compound library for P5‐specific inhibitors, and identified two candidate compounds (anacardic acid and NSC74859). Interestingly, anacardic acid inhibited the reductase activity of P5, but did not inhibit the activity of protein disulfide isomerase (PDI), thiol‐disulfide oxidoreductase ERp57, or thioredoxin. NSC74859 inhibited all these enzymes. When we examined the effects of these compounds on the secretion of soluble major histocompatibility complex class‐I‐related gene A (MICA) from cancer cells, anacardic acid was found to decrease secretion. In addition, anacardic acid was found to reduce the concentration of glutathione up‐regulated by the anticancer drug 17‐demethoxygeldanamycin in cancer cells. These results suggest that anacardic acid can both inhibit P5 reductase activity and decrease the secretion of soluble MICA from cancer cells. It might be a novel and potent anticancer treatment by targeting P5 on the surface of cancer cells.
Biosynthesis of Nudicaulins: A 13CO2‐Pulse/Chase Labeling Study with Papaver nudicaule
Authors: Tatsis Evangelos C. , Eylert Eva , Maddula Ravi Kumar , Ostrozhenkova Elena , Svatoš Aleš , Eisenreich Wolfgang , Schneider Bernd 
Published: June 2014

AbstractNudicaulins are unique alkaloids responsible for the yellow color of the petals of some papaveraceaous plants. To elucidate the unknown biosynthetic origin of the skeleton, a 13CO2‐pulse/chase experiment was performed with growing Papaver nudicaule plants. 13C NMR analysis revealed more than 20 multiple 13C‐enriched isotopologues in nudicaulins from the petals of 13CO2‐labeled plants. The complex labeling pattern was compared with the isotopologue composition of a kaempferol derivative that was isolated from petals of the same 13CO2‐labeled plants. The deconvolution of the labeling profiles indicated that the nudicaulin scaffold is assembled from products or intermediates of indole metabolism, the phenylpropanoid pathway, and the polyketide biosynthesis. Naringenin‐type compounds and tryptophan/tryptamine are potential substrates for the condensation reaction finally generating the aglycone skeleton of nudicaulins.
Synthesis of Platinum Nanoparticles by using Molybdenum Disulfide as a Template and its Application to Enzyme‐like Catalysis
Authors: Duan Kaiyue , Du Yongling , Feng Qingliang , Ye Xiaoliang , Xie Hong , Xue Muyin , Wang Chunming 
Published: June 2014

AbstractPlatinum nanoparticles were synthesized with molybdenum disulfide (MoS2) as a template through a facile hydrothermal method. The as‐prepared nanocomposites (Pt‐MoS2) were characterized by TEM, HRTEM, electrochemical impedance spectroscopy, and X‐ray photoelectron spectroscopy, and they were then used to fabricate a biosensor for enzyme‐like catalysis of hydrogen peroxide (H2O2). The electrochemical activity for the reduction reactions of H2O2 was evaluated in N2‐saturated phosphate buffer solution. The cyclic voltammetry and amperometry results demonstrated that the biosensor modified by the nanocomposites exhibited a fast amperometric response and excellent electrocatalytic activity for reduction of H2O2 with a wide linear range from 0.004 to 48.5 mM and a low detection limit of 0.001 mM at 3σ. Thus, the present work indicates that Pt nanoparticles can be synthesized on the surface of few‐layer MoS2 owing to interfacial PtS bonds and that the composites show a clear enhancement in the catalytic activity relative to that of the platinum nanoparticles alone. This method provides a new way to prepare metal nanoparticles for extensive applications in the field of catalysis.
Chiral Organoborane Lewis Pairs Derived from Pyridylferrocene
Authors: Chen Jiawei , Lalancette Roger A. , Jäkle Frieder 
Published: June 2014

AbstractIn an effort to develop a new class of redox‐active chiral Lewis pairs, pyridine and borane moieties with different steric and electronic properties were introduced onto a planar chiral 1,2‐disubstituted ferrocene framework. Metathesis of lithiated, stannylated, or mercuriated pyridylferrocenes with boron halides afforded (pR)‐2‐[bis(pentafluorophenyl)boryl]‐1‐(3,5‐dimethylpyrid‐2‐yl)ferrocene (4‐Pf), (pR)‐2‐[dimesitylboryl]‐1‐(3,5‐dimethylpyrid‐2‐yl)ferrocene (4‐Mes), (pS)‐2‐(bis(pentafluorophenyl)boryl)‐1‐(2‐trimethylsilylpyrid‐6‐yl)ferrocene (5‐Pf), or (pS)‐2‐[dimesitylboryl]‐1‐(2‐trimethylsilylpyrid‐6‐yl)ferrocene (5‐Mes). The borylated products were analyzed by multinuclear NMR spectroscopy, HRMS, and single‐crystal X‐ray diffraction. Chiral HPLC and optical‐rotation measurements were employed to assess the stereoselectivity of the borylation process and to establish the correct stereochemical assignments. The strength of the B–N interactions were investigated in solution and in the solid state. Compounds 4‐Pf and 4‐Mes formed robust ‘closed’ BN heterocyclic systems that proved to be perfectly stable to air and moisture, whereas 5‐Pf established a dynamic equilibrium, in which the BN heterocycle was observed exclusively at room temperature, but opened up at high temperature according to 19F NMR exchange spectroscopy data. As a consequence, 5‐Pf reacted readily with a molecule of water to generate a ring‐opened pyridinium borate. The combination of bulky borane and bulky pyridyl groups in 5‐Mes led to a completely ‘open’ frustrated Lewis pair system with uncomplexed pyridine and borane groups, even at room temperature. Electrochemical studies were performed and the effect of preparative ferrocene oxidation on the structural features was also explored.
1,10‐Phenanthroline and Non‐Symmetrical 1,3,5‐Triazine Dipicolinamide‐Based Ligands For Group Actinide Extraction
Authors: Bisson Julia , Dehaudt Jérémy , Charbonnel Marie‐Christine , Guillaneux Denis , Miguirditchian Manuel , Marie Cécile , Boubals Nathalie , Dutech Guy , Pipelier Muriel , Blot Virginie , Dubreuil Didier 
Published: June 2014

AbstractThe synthesis and evaluation of new extractants for spent nuclear fuel reprocessing are described. New bitopic ligands constituted of phenanthroline and 1,3,5‐triazine cores functionalized by picolinamide groups were designed. Synthetic routes were investigated and optimized to obtain twelve new polyaza‐heterocyclic ligands. In particular, an efficient and versatile methodology was developed to access non‐symmetric 2‐substituted‐4,6‐di(6‐picolin‐2‐yl)‐1,3,5‐triazines from the 1,3,5‐triazapentadiene precursor in the presence of anhydride reagents. Extraction studies showed the ability of both ligand series to extract and separate actinides selectively at different oxidation states (UVI, NpV,VI, AmIII, CmIII, and PuIV) from an acidic solution (3 M HNO3). Phenanthroline‐based ligands show the most promising efficiency for use in the group actinide extraction (GANEX) process due to a higher number of donor nitrogen atoms and a suitable pre‐organization of the dipicolinamide‐1,10‐phenanthroline architecture.
Ring Opening and Bidentate Coordination of Amidinate Germylenes and Silylenes on Carbonyl Dicobalt Complexes: The Importance of a Slight Difference in Ligand Volume
Authors: Cabeza Javier A. , García‐Álvarez Pablo , Pérez‐Carreño Enrique , Polo Diego 
Published: June 2014

AbstractThe reactions of [Co2(CO)8] with one equiv of the benzamidinate (R2bzam) group‐14 tetrylenes [M(R2bzam)(HMDS)] (HMDS=N(SiMe3)2; 1: M=Ge, R=iPr; 2: M=Si, R=tBu; 3: M=Ge, R=tBu) at 20 °C led to the monosubstituted complexes [Co2{κ1MM(R2bzam)(HMDS)}(CO)7] (4: M=Ge, R=iPr; 5: M=Si, R=tBu; 6: M=Ge, R=tBu), which contain a terminal κ1M–tetrylene ligand. Whereas the Co2Si and Co2Ge tert‐butyl derivatives 5 and 6 are stable at 20 °C, the Co2Ge isopropyl derivative 4 evolved to the ligand‐bridged derivative [Co2{μ‐κ2Ge,N‐Ge(iPr2bzam)(HMDS)}(μ‐CO)(CO)5] (7), in which the Ge atom spans the CoCo bond and one arm of the amidinate fragment is attached to a Co atom. The mechanism of this reaction has been modeled with the help of DFT calculations, which have also demonstrated that the transformation of amidinate‐tetrylene ligands on the dicobalt framework is negligibly influenced by the nature of the group‐14 metal atom (Si or Ge) but is strongly dependent upon the volume of the amidinate NR groups. The disubstituted derivatives [Co2{κ1MM(R2bzam)(HMDS)}2(CO)6] (8: M=Ge, R=iPr; 9: M=Si, R=tBu; 10: M=Ge, R=tBu), which contain two terminal κ1M–tetrylene ligands, have been prepared by treating [Co2(CO)8] with two equiv of 1–3 at 20 °C. The IR spectra of 8–10 have shown that the basicity of germylenes 1 and 3 is very high (comparable to that of trialkylphosphanes and 1,3‐diarylimidazol‐2‐ylidenes), whereas that of silylene 2 is even higher.
Catalytic Self‐Propulsion of Supramolecular Capsules Powered by Polyoxometalate Cargos
Authors: del Mercato Loretta L. , Carraro Mauro , Zizzari Alessandra , Bianco Monica , Miglietta Ruggero , Arima Valentina , Viola Ilenia , Nobile Concetta , Sorarù Antonio , Vilona Debora , Gigli Giuseppe , Bonchio Marcella , Rinaldi Rosaria 
Published: June 2014

AbstractMulticompartment, spherical microcontainers were engineered through a layer‐by‐layer polyelectrolyte deposition around a fluorescent core while integrating a ruthenium polyoxometalate (Ru4POM), as molecular motor, vis‐à‐vis its oxygenic, propeller effect, fuelled upon H2O2 decomposition. The resulting chemomechanical system, with average speeds of up to 25 μm s−1, is amenable for integration into a microfluidic set‐up for mixing and displacement of liquids, whereby the propulsion force and the resulting velocity regime can be modulated upon H2O2‐controlled addition.
Extending Documentation‐Based Models towards an Efficient Integration into Commercial Process Simulators
Authors: Merchan Victor Alejandro , Tolksdorf Gregor , Kraus Robert , Wozny Günter 
Published: June 2014

AbstractIn this contribution an extension of the principle of modeling in the documentation level towards the model integration in process modeling tools is presented. The definition of documentation‐based, problem‐specific interfaces allows a highly specific code generation of customized user models, including physical property calls and port definitions, while keeping the model development at a tool‐independent level. Two case studies concerning the rigorous model development and simulation of multiphase liquid systems show the potential of this approach.
High‐Throughput Multiplexing Gas Chromatography
Authors: Siegle Alexander F. , Trapp Oliver 
Published: June 2014

AbstractDie Anwendung von Informationstechnologie in der Gaschromatographie wird vorgestellt. Multiplexing‐Gaschromatographie steigert Auslastungsgrad, Signal/Rausch‐Verhältnis und ermöglicht außergewöhnlich hohe Probendurchsätze. Parameter wie Sequenzlänge, Modulationsintervall sowie Anzahl wiederholter Injektionen im Hochdurchsatzmodus bestimmen die Leistungsfähigkeit dieser Methode. Die vorgestellte Technik eröffnet neue Perspektiven in der Prozessanalytik durch kontinuierliche Überwachung eines chemischen Prozesses bei gleichzeitiger Analyse aller vorhandenen Analyte.
Synthesis and Biological Evaluation of Papain‐Family Cathepsin L‐Like Cysteine Protease Inhibitors Containing a 1,4‐Benzodiazepine Scaffold as Antiprotozoal Agents
Authors: Ettari Roberta , Pinto Andrea , Tamborini Lucia , Angelo Ilenia C. , Grasso Silvana , Zappalà Maria , Capodicasa Natale , Yzeiraj Laura , Gruber Esther , Aminake Makoah N. , Pradel Gabriele , Schirmeister Tanja , De Micheli Carlo , Conti Paola 
Published: June 2014

AbstractNovel papain‐family cathepsin L‐like cysteine protease inhibitors endowed with antitrypanosomal and antimalarial activity were developed, through an optimization study of previously developed inhibitors. In the present work, we studied the structure–activity relationships of these derivatives, with the aim to develop new analogues with a simplified and more synthetically accessible structure and with improved antiparasitic activity. The structure of the model compounds was significantly simplified by modifying or even eliminating the side chain appended at the C3 atom of the benzodiazepine scaffold. In addition, a simple methylene spacer of appropriate length was inserted between the benzodiazepine ring and the 3‐bromoisoxazoline moiety. Several rhodesain and falcipain‐2 inhibitors displaying single‐digit micromolar or sub‐micromolar antiparasitic activity against one or both parasites were identified, with activities that were one order of magnitude more potent than the model compounds.
Anticancer Ruthenium(III) Complex KP1019 Interferes with ATP‐Dependent Ca2+Translocation by Sarco‐Endoplasmic Reticulum Ca2+‐ATPase (SERCA)
Authors: Sadafi Fabrizio‐Zagros , Massai Lara , Bartolommei Gianluca , Moncelli Maria Rosa , Messori Luigi , Tadini‐Buoninsegni Francesco 
Published: June 2014

AbstractSarco‐endoplasmic reticulum Ca2+‐ATPase (SERCA), a P‐type ATPase that sustains Ca2+transport and plays a major role in intracellular Ca2+homeostasis, represents a therapeutic target for cancer therapy. Here, we investigated whether ruthenium‐based anticancer drugs, namely KP1019 (indazolium [trans‐tetrachlorobis(1H‐indazole)ruthenate(III)]), NAMI‐A (imidazolium [trans‐tetrachloro(1H‐imidazole)(S‐dimethylsulfoxide)ruthenate(III)]) and RAPTA‐C ([Ru(η6‐p‐cymene)dichloro(1,3,5‐triaza‐7‐phosphaadamantane)]), and cisplatin (cis‐diammineplatinum(II) dichloride) might act as inhibitors of SERCA. Charge displacement by SERCA adsorbed on a solid‐supported membrane was measured after ATP or Ca2+concentration jumps. Our results show that KP1019, in contrast to the other metal compounds, is able to interfere with ATP‐dependent translocation of Ca2+ions. An IC50value of 1 μMwas determined for inhibition of calcium translocation by KP1019. Conversely, it appears that KP1019 does not significantly affect Ca2+binding to the ATPase from the cytoplasmic side. Inhibition of SERCA at pharmacologically relevant concentrations may represent a crucial aspect in the overall pharmacological and toxicological profile of KP1019.