bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemotaxonomic and Micromorphological Traits of Satureja montana L. and S. subspicataVis. (Lamiaceae)
Authors: Dunkić Valerija , Kremer Dario , Dragojević Müller Ivna , Stabentheiner Edith , Kuzmić Sunčica , Jurišić Grubešić Renata , Vujić Lovorka , Kosalec Ivan , Randić Marko , Srečec Siniša , Bezić Nada 
Published: December 2012

AbstractSatureja montana and S. subspicata are used as spice, pepper substitute, for preparing tea, juice, and as a medicine. Fourteen populations (seven per species) of Satureja montana L. and S. subspicata Vis. growing in Croatia were examined to determine the chemical composition of the essential oil (analyzed by GC‐FID and GC/MS), the content of macroelements (Na, K, Ca, Mg) and trace elements (B, Fe, Cu, Mn, Zn, Al, Pb, Cr, Cd, Ni, Hg, As) analyzed by ICP‐AES, antioxidant compounds (analyzed by UV/VIS spectrophotometer), and the types and distribution of trichomes (analyzed by scanning electron microscopy). The main constituents of the essential oil were carvacrol and thymol in S. montana (all populations belong to one phenol chemotype), while α‐eudesmol, β‐eudesmol, and spathulenol dominated in S. subspicata (three chemotypes could be distinguished). Both species possess considerably higher quantities of Ca and Mg, and moderate concentrations of K and Na, while Hg and As levels were below the limit of quantification. Non‐glandular trichomes, peltate trichomes, and three types of capitate trichomes were observed on leaves, stem, calyx, and corolla.
Essential‐Oil and Fatty‐Acid Composition, and Antioxidant Activity of Extracts of Ficaria kochii
Authors: Tavakoli Rahmatollah , Mohadjerani Maryam , Hosseinzadeh Rahman , Tajbakhsh Mahmood , Naqinezhad Alireza 
Published: December 2012

AbstractThe essential‐oil and fatty‐acid composition of the aerial parts of Ficaria kochii (Ledeb.) Iranshahr & Rech.f. native to Iran, and the antioxidant activity of various extracts of this plant were examined. The study by GC‐FID and GC/MS analysis of the essential oil resulted in the identification of 61 compounds, representing 86.01% of the total oil composition. Phytol (10.49%), farnesol (7.72%), methyl linoleate (5.57%), and α‐farnesene (4.96%) were the main components. The fatty‐acid composition of the aerial parts of F. kochii was also analyzed by GC/MS. The major components were palmitic acid (25.9%), linolenic acid (25.3%), and linoleic acid (17.5%). Polyunsaturated fatty acids (PUFAs) were found in higher amounts than saturated fatty acids. The possible antioxidant activity of various extracts (prepared by using solvents with different polarity) of the F. kochii aerial parts was evaluated by screening for their 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical‐scavenging activity, FeIII‐reducing power, total antioxidant activity, and inhibitory activity in the linoleic acid‐peroxidation system. H2O proved to be the most efficient solvent for the extraction of antioxidants, as the H2O extract contained the highest amount of phenolic compounds (2.78±0.23 GAE/g dry matter) and also exhibited the strongest antioxidant capacity in all the assays used. The results of the present investigation demonstrated that the aerial parts of F. kochii can be used as natural and safe nutrition supplement in place of synthetic ones.
Chemical Variability of the Leaf Essential Oil of Xylopia aethiopica (Dunal) A.Rich. from Côte d'Ivoire
Authors: Yapi Thierry Acafou , Boti Jean Brice , Ahibo Coffy Antoine , Bighelli Ange , Castola Vincent , Casanova Joseph , Tomi Félix 
Published: December 2012

AbstractThe chemical composition of 48 essential‐oil samples isolated from the leaves of Xylopia aethiopica harvested in six Ivoirian forests was investigated by GC‐FID and 13C‐NMR analyses. In total, 23 components accounting for 82.5–96.1% of the oil composition were identified. The composition was dominated by the monoterpene hydrocarbons β‐pinene (up to 61.1%) and α‐pinene (up to 18.6%) and the sesquiterpene hydrocarbon germacrene D (up to 28.7%). Hierarchical cluster and principal component analyses allowed the distinction of two groups on the basis of the β‐pinene and germacrene D contents. The chemical composition of the oils of Group I (38 oil samples) was clearly dominated by β‐pinene, while those of Group II (10 samples) were characterized by the association of β‐pinene and germacrene D. The leaves collected in the four inland forests produced β‐pinene‐rich oils (Group I), while the oil samples belonging to Group II were isolated from leaves harvested in forests located near the littoral.
Dipeptides as Leaving Group in the Enzyme‐Catalyzed DNA Synthesis
Authors: Song Xiao‐Ping , Bouillon Camille , Lescrinier Eveline , Herdewijn Piet 
Published: December 2012

AbstractConjugates of 2′‐deoxyadenosine monophosphate with dipeptides have been synthesized and tested as substrates for several polymerases. Although the incorporation efficiency is not very high, it demonstrates that some of these dipeptides can be accommodated in the active site of polymerases and function as leaving groups in the enzymatic synthesis of DNA.
On 3LEZ, a Deep‐Sea Halophilic Protein with in vitro Class‐A β‐Lactamase Activity: Molecular‐Dynamics, Docking, and Reactivity Simulations
Authors: Pietra Francesco 
Published: December 2012

AbstractThis work shows that a deep‐sea protein, 3LEZ, with known in vitro β‐lactamase activity, proved stable, substantially in the conformation detected by X‐ray diffraction of the crystal, when subjected to molecular‐dynamics (MD) simulations under conditions compatible with shallow seas. Docking simulations showed that the β‐lactamase active site S85 of 3LEZ (S70 in Ambler numbering) is the preferential binding pocket for not only β‐lactam antibiotics and inhibitors, but, surprisingly, also for a wide variety of other biologically active compounds in various chemical classes, including marine metabolites. In line with the in vitro β‐lactamase activity, a) affinities on docking β‐lactam antibiotics and inhibitors onto 3LEZ were found to roughly parallel published Km and Ki values, obtained from MichaelisMenten kinetics under room conditions, and b) DFT calculations agreed with experiments that the irreversible reaction of the β‐lactamase inhibitor clavulanic acid with the whole S85 catalytic center of 3LEZ is spontaneous. These observations must be viewed in the light that a) the compounds in other chemical classes showed comparable affinities, and, in some cases, even higher than β‐lactams, for the S85 active site, b) Km and Ki data are not available at the high hydrostatic pressure of the deep sea, where 3LEZ is believed to have evolved, c) an inverse order of affinities for the β‐lactams, with respect to both experimentation and simulations at room conditions, was observed from comparative docking simulations with 3LEZ derived from MD under high hydrostatic pressure. Although MD requires a general assessment for high hydrostatic pressure before c) above is given the same weight as all other observations, this work questions the conclusion that the in vitro determined β‐lactamase activity represents the ecological role of 3LEZ.
Sonication‐Induced Coiled Fibrous Architectures of Boc‐L‐Phe‐L‐Lys(Z)‐OMe
Authors: Afrasiabi Rouzbeh , Kraatz Heinz‐Bernhard 
Published: December 2012

AbstractAn ultra‐short peptide Boc‐L‐Phe‐L‐Lys(Z)‐OMe (Z=carbobenzyloxy) was shown to act as a highly efficient and versatile low molecular weight gelator (LMWG) for a variety of aliphatic and aromatic solvents under sonication. Remarkably, this simple dipeptide is not only able to form coiled fibres but also demonstrates self‐healing and thermal chiroptical switching behaviour. The formation of coiled assemblies was found to be influenced by the nature of the solvent and the presence of an additive. By exploiting these properties it was possible to modulate the macroscopic and microscopic properties of the organogels of this ultra‐short peptide, allowing the formation of highly ordered single‐domain networks of helical fibres with dimeric or alternatively fibre‐bundle morphology. The organogels were characterized by using FTIR, SEM, NMR and circular dichroism (CD) spectroscopy. Interestingly, CD experiments showed that the organogels of Boc‐L‐Phe‐L‐Lys(Z)‐OMe in aromatic solvents exhibit thermal chiroptical switching. This behaviour was hypothesized to stem from changes in the morphology of the gel accompanied by conformational transformation of the gelling agent. The fact that such a small peptide can demonstrate hierarchical assemblies and the possibility of controlling the self‐association is rather intriguing. The self‐healing ability, chiroptical switching and more importantly the formation of helical assemblies by Boc‐L‐Phe‐L‐Lys(Z)‐OMe under sonication, make this dipeptide an interesting example of the self‐assembly ability of ultra‐short peptides.
Mapping the Metal Positions inside Spherical C80 Cages: Crystallographic and Theoretical Studies of Ce2@D5h‐C80 and Ce2@Ih‐C80
Authors: Feng Lai , Suzuki Mitsuaki , Mizorogi Naomi , Lu Xing , Yamada Michio , Akasaka Takeshi , Nagase Shigeru 
Published: December 2012

AbstractThe dynamic positions of the dimetallic cluster inside the mid‐sized spherical cages of C80–C82 have been seldom studied, despite the high abundance of M2@C2n (2n=80, 82) species among various endohedral metallofullerenes. Herein, using crystallographic methods, we first unambiguously map the metal positions for both Ce2@D5h‐C80 and Ce2@Ih‐C80, showing how the symmetry or geometrical change in cage structure can influence the motional behavior of the cluster. Inside the D5h cage, the primary cerium sites have been identified along a cage belt of the contiguous hexagons, which suggests the significant influence of such a cage motif on endohedral cluster motion. Further analysis revealed a distorted D5h cage owing to the “punch‐out” effect of cerium atoms. The consequence is the presence of two localized electrostatic potential minima inside the cage of (D5h‐C80)6−, thus reflecting the primary ionic cerium–cage interaction. In contrast, a different motional behavior of Ce2 cluster was observed inside the Ih cage. With the major cerium sites, the molecule of Ce2@Ih‐C80 presented an approximate D2h configuration. With the combined theoretical study, we propose that the additional unidentified influence of NiII(OEP) (OEP=octaethylporphyrin) might be also relevant for the location of cerium sites inside the Ih cage.
A Resin‐Linker‐Vector Approach to Radiopharmaceuticals Containing 18F: Application in the Synthesis of O‐(2‐[18F]‐Fluoroethyl)‐L‐tyrosine
Authors: Topley Amy C. , Isoni Valerio , Logothetis Thomas A. , Wynn Duncan , Wadsworth Harry , Gibson Alex M. R. , Khan Imtiaz , Wells Neil J. , Perrio Cécile , Brown Richard C. D. 
Published: December 2012

AbstractA Resin‐linker‐vector (RLV) strategy is described for the radiosynthesis of tracer molecules containing the radionuclide 18F, which releases the labelled vector into solution upon nucleophilic substitution of a polystyrene‐bound arylsulfonate linker with [18F]‐fluoride ion. Three model linker‐vector molecules 7 a–c containing different alkyl spacer groups were assembled in solution from (4‐chlorosulfonylphenyl)alkanoate esters, exploiting a lipase‐catalysed chemoselective carboxylic ester hydrolysis in the presence of the sulfonate ester as a key step. The linker‐vector systems were attached to aminomethyl polystyrene resin through amide bond formation to give RLVs 8 a–c with acetate, butyrate and hexanoate spacers, which were characterised by using magic‐angle spinning (MAS) NMR spectroscopy. On fluoridolysis, the RLVs 8 a, b containing the longer spacers were shown to be more effective in the release of the fluorinated model vector (4‐fluorobutyl)phenylcarbamic acid tert‐butyl ester (9) in NMR kinetic studies and gave superior radiochemical yields (RCY≈60 %) of the 18F‐labelled vector. The approach was applied to the synthesis of the radiopharmaceutical O‐(2‐[18F]‐fluoroethyl)‐L‐tyrosine ([18F]‐FET), delivering protected [18F]‐FET in >90 % RCY. Acid deprotection gave [18F]‐FET in an overall RCY of 41 % from the RLV.
A New Access Route to Functionalized Cispentacins from Norbornene β‐Amino Acids
Authors: Kiss Loránd , Cherepanova Maria , Forró Enikő , Fülöp Ferenc 
Published: December 2012

AbstractAn efficient and simple new stereocontrolled access route to novel disubstituted cispentacin derivatives with multiple stereogenic centers from norbornene β‐lactam has been developed. The synthesis involves olefinic bond functionalization by dihydroxylation followed by oxidative ring cleavage and transformation of the dialdehyde intermediate through a Wittig reaction.
Concise Synthesis of Well‐Defined Linear and Branched Oligothiophenes with Nickel‐Catalyzed Regiocontrolled Cross‐Coupling of 3‐Substituted Thiophenes by Catalytically Generated Magnesium Amide
Authors: Tanaka Shota , Tanaka Daiki , Tatsuta Go , Murakami Kohei , Tamba Shunsuke , Sugie Atsushi , Mori Atsunori 
Published: December 2012

AbstractThe synthesis of linear and branched oligothiophenes of well‐defined structures is performed with regioselective deprotonation of 3‐substituted thiophenes and nickel‐catalyzed cross‐coupling of the thus formed metalated species with a bromothiophene. The reaction of 3‐hexylthiophene with EtMgCl and 2,2,6,6‐tetramethylpiperidine (TMP‐H, 10 mol %) induces the metalation selectively at the 5‐position by use of the catalytically generated hindered magnesium amide (TMPMgCl) and the subsequent reaction of a 2‐halo‐3‐hexylthiophene (bromide or chloride) in the presence of a nickel catalyst affords a head‐to‐tail (HT)‐type dimer. By repeating the same sequence, the linear oligothiophene up to a 4‐mer is synthesized in good yield. The reaction of 3‐hexylthiophene with 2,3‐dibromothiophene also takes place to afford a branched oligothiophene 3‐mer in quantitative yield. The obtained 3‐mer is also metalated at the sterically less‐hindered position in a regioselective manner furnishing a 7‐mer in >99 % yield after a further coupling reaction with 2,3‐dibromothiophene. These dendrimers react with several multifunctionalized organic electrophiles, leading to a variety of branched oligothiophenes.
Comparison of Two‐Fluid and Discrete Particle Modeling of Dense Gas‐Particle Flows in Gas‐Fluidized Beds
Authors: Wang Junwu , van der Hoef Martin A. , Kuipers J. A. M. 
Published: December 2012

AbstractBoth two‐fluid models embedding the kinetic theory of granular flow for particulate phase stress (TFM) and discrete particle models (DPM) are widely used for the numerical simulation of gas fluidization. In this study, a detailed comparison between results obtained from both TFM and DPM is reported, including axial and radial solid concentration profiles, solids circulation patterns, pressure drop and its standard deviation and granular temperature. It was shown that good agreement can be obtained even in cases of low restitution coefficient, which suggests the possible applicability of kinetic theory of granular flow beyond its nominal range of validity and clearly indicates that the continuum treatment of the solids phase in TFM provides a good approximation of its discrete nature.
Novel, Rotary Oscillated, Scalable Single‐Use Bioreactor Technology for the Cultivation of Animal Cells
Authors: Kauling Jörg , Brod Helmut , Jenne Marc , Waldhelm Annette , Langer Uwe , Bödeker Berthold 
Published: December 2012

AbstractThe BaySHAKE® single‐use bioreactor is based on the motion principle of rotary oscillation of a polyhedral container. This fundamental working principle facilitates mixing and oxygen transfer to animal cell cultures in a simple, robust and cost‐efficient single‐use system without internal moving parts. In‐depth hydrodynamic characterization shows that the bioreactor provides mixing and oxygen transfer in a low‐shear environment over a range of scales up to several cubic meters. A biological comparison of novel single‐use technology in scales from 50 to 1000 L with the re‐usable standard deep‐tank technology in scales from 10 to 200 L confirms the technical feasibility and shows good biological equivalence for the production of monoclonal antibodies by CHO cells.
Herstellung moderner Grippeimpfstoffe
Authors: Genzel Yvonne , Frensing Timo , Reichl Udo 
Published: December 2012

AbstractNoch immer werden 95 % der verfügbaren Grippeimpfstoffdosen mit Hilfe von Hühnereiern hergestellt. Spätestens seit der H1N1‐Influenza‐Pandemie von 2009 ist vielen Menschen jedoch bewusst geworden, dass es im Ernstfall schwierig sein kann, Impfstoffe rechtzeitig und in ausreichender Menge bereitzustellen. Insbesondere ist es wichtig, alternative Herstellungsverfahren weiter zu verbessern oder neue Methoden zu entwickeln. Die hier vorgestellten zellkulturbasierten Prozesse stellen eine vielversprechende Möglichkeit dar, skalierbare und robuste Produktionsverfahren zu etablieren. Es ist davon auszugehen, dass das volle Potential dieser Prozesse bei weitem noch nicht ausgeschöpft ist und durch weitere verfahrenstechnische Maßnahmen, vor allem aber auch durch eine gezielte Optimierung der biologischen Systeme, erhebliche Ausbeutesteigerungen und Produktverbesserungen möglich sind.
Iron(II) α‐Aminopyridine Complexes and Their Catalytic Activity in Oxidation Reactions: A Comparative Study of Activity and Ligand Decomposition
Authors: Lenze Matthew , Martin Erin T. , Rath Nigam P. , Bauer Eike B. 
Published: December 2012

AbstractNew well‐defined FeII complexes bearing bi‐ and tridentate α‐aminopyridine ligands were synthesized, and their catalytic activity in the oxidation of hydrocarbons and alcohols utilizing peroxide oxidants was investigated. The tridendate bis(picolyl)amine ligand 6 and its benzylated analogue 7 were converted into complexes [FeII(6)2]OTf2 (96 %, X‐ray; OTf=CF3SO3−) and [FeII(7)2]OTf2 (90 %). The bidentate aminopyridine ligand 8 was converted into [FeII(8)2(OTf)2] (93 %, X‐ray). The new complexes are catalytically active in the oxidation of secondary alcohols and benzylic methylene groups to the corresponding ketones, of toluene to benzaldehyde, and of cyclohexene to cyclohexene oxide (3 mol % catalyst, tBuOOH (4 equiv), RT, 2–6 h, 28 to 85 % yield of isolated product). The catalytic oxidation of cyclohexane with ROOH (R=H, tBu) to an alcohol/ketone mixture with low ratio revealed that these oxidations follow largely a radical mechanism, except when [FeII(6)2]OTf2 was employed and H2O2 was added slowly. Together with known bi‐ and tetradendate iron complexes, a comparative study showed slight reactivity differences for the newly prepared complexes, with the highest observed for [FeII(6)2]OTf2 and [FeII(7)2]OTf2. The reaction of the new complexes with peroxides was followed over time by UV/Visible spectroscopy; this revealed a fast reaction between the two reactants within minutes. Ligand‐decomposition pathways were investigated, and revealed that the NCH2 units of the complexes are rapidly oxidized to the corresponding amides NCO. The iron complex [FeII(6)2]OTf2 showed no decrease in catalytic activity and a moderate decrease in selectivity when first subjected to oxidative conditions similar to those employed in catalysis. Thus, oxidative ligand deterioration had a marginal effect on the catalytic activity of the iron complex [FeII(6)2]OTf2.
Synthesis of Chalcogenidoimidodiphosphinato–RhI Complexes and DFT Investigation of Their Catalytic Activation in Olefin Hydroformylation
Authors: Grigoropoulos Alexios , Maganas Dimitrios , Symeonidis Dimitrios , Giastas Petros , Cowley Andrew R. , Kyritsis Panayotis , Pneumatikakis Georgios 
Published: December 2012

AbstractThe synthesis and spectroscopic characterization of [Rh{R2P(S)NP(S)R2‐S,S′}(cod)] [cod = 1,5‐cyclooctadiene; R = Ph (1), iPr (4)], [Rh{Ph2P(S)NP(S)Ph2‐S,S′}(CO)2] (2) and [Rh{Ph2P(S)NP(S)Ph2‐S,S′}(CO)(PPh3)] (3) is described. The crystal structures of complexes 1 and 3 are also presented. The synthesized RhI complexes are essentially not catalytically active against olefin hydroformylation, in contrast to the previously reported complex [Rh{Ph2P(O)NPPh2‐P,O}(CO)(PPh3)] (6). Differences in the catalytic activity were interpreted with the aid of a well‐defined DFT‐based protocol involving relativistic effects and dispersion correction. The steric and electronic effects of the RhI coordination environment with respect to their activation by H2 are discussed. The results demonstrate that the presence of the more electronegative oxygen atom in the RhI coordination sphere polarizes the H–H bond and promotes its heterolytic cleavage, thereby leading to the formation of a RhI–monohydride complex in which the oxygen atom of the ligand is protonated.
Two Types of Polyoxometalates Based on Circular P8W48 Cluster Units and Different Inclusions of Tetralanthanide and Octamanganese Centers
Authors: Huang Ling , Cheng Lin , Fang Wei‐Hui , Wang Sa‐Sa , Yang Guo‐Yu 
Published: December 2012

AbstractTwo types of new polyoxometalates (POMs) based on circular P8W48 clusters with different tetralanthanide (Ln) clusters and octamanganese centers, [K(H2O)2]4[K4(μ‐H2O)4(H2O)4]2{[Ln2(μ‐OH)4(H2O)x]2(H24P8W48O184)}·yH2O [Ln = Nd (1), Sm (2), Tb (3)] and [K(H2O)2]4[K4(μ‐H2O)8]2[K(H2O)]8{[Mn8(H2O)16](H4P8W48O184)}·36H2O (4) have been synthesized under hydrothermal conditions and characterized by single‐crystal X‐ray diffraction, elemental analysis, IR spectroscopy, thermogravimetry (TG), and powder XRD. Compounds 1–3 are the first series of Ln‐containing P8W48‐based POMs that use P2W12O4814– as the precursor; previously known P8W48‐based POMs used P8W48O18440– as the precursor. In 4, eight manganese ions were incorporated. Owing to the different radii of the Ln and Mn ions, the four large Ln ions are divided into two {Ln2} clusters located on two sides of the cavity of the P8W48 wheel in 1–3, but the eight small manganese ions in 4 only bond to the inside of the P8W48 wheel and do not form manganese clusters. The magnetic properties of 3 are discussed.
Trilacunary Keggin‐Type POMs as Versatile Building Blocks for Lanthanoid Silicotungstates
Authors: Ni Lubin , Spingler Bernhard , Weyeneth Stephen , Patzke Greta R. 
Published: December 2012

AbstractThree new lanthanoid‐substituted polyoxotungstates based on open Wells–Dawson fragments {[Ln2(H2O)7SiW18O66]10– [Ln = EuIII (Eu‐1 and Eu‐2), TbIII (Tb‐1)]} and a new sandwich‐type polyoxometalate constituted of Keggin‐type monolacunary anions {[Eu(α‐SiW11O39)2]13– (Eu‐3)} were obtained from the trilacunary Keggin POM Na10[SiW9O34]·23 H2O and lanthanoid salts as precursors. All compounds were comprehensively characterized by inductively coupled plasma (ICP) and thermogravimetric analyses and by FT‐IR and UV/Vis spectroscopy, as well as by powder X‐ray diffraction (PXRD) and single‐crystal X‐ray diffraction. Eu‐1 and Tb‐1 exhibit 3D architectures of dimeric [Ln2(H2O)7SiW18O66]10– units connected through LnIII linkers, whereas Eu‐2 displays a 2D sheet‐like framework. Eu‐3 exists in two enantiomeric forms, due to the C2 symmetry of the central square‐antiprismatic EuO8 polyhedron. The structure‐directing influence of the Ln cations on the emerging POM architectures is investigated in detail. Photoluminescence of Eu‐1, Eu‐2, Eu‐3 and Tb‐1 can be ascribed to the characteristic emissions of the EuIII and TbIII cations, respectively. The electrochemical properties of all compounds were investigated by cyclic voltammetry in sodium acetate buffer solution as supporting electrolyte. The magnetic susceptibility of Tb‐1 was studied in the temperature range between 5 and 300 K and indicated paramagnetic behavior.