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81.
Venkat N. Vangaveti Venkatesh M. Shashidhar Catherine Rush Usman H. Malabu Roy R. Rasalam Fiona Collier Bernhard T. Baune Richard L. Kennedy 《Lipids》2014,49(12):1181-1192
Macrophage apoptosis, a key process in atherogenesis, is regulated by oxidation products, including hydroxyoctadecadienoic acids (HODEs). These stable oxidation products of linoleic acid (LA) are abundant in atherosclerotic plaque and activate PPARγ and GPR132. We investigated the mechanisms through which HODEs regulate apoptosis. The effect of HODEs on THP‐1 monocytes and adherent THP‐1 cells were compared with other C18 fatty acids, LA and α‐linolenic acid (ALA). The number of cells was reduced within 24 hours following treatment with 9‐HODE (p < 0.01, 30 μM) and 13 HODE (p < 0.01, 30 μM), and the equivalent cell viability was also decreased (p < 0.001). Both 9‐HODE and 13‐HODE (but not LA or ALA) markedly increased caspase‐3/7 activity (p < 0.001) in both monocytes and adherent THP‐1 cells, with 9‐HODE the more potent. In addition, 9‐HODE and 13‐HODE both increased Annexin‐V labelling of cells (p < 0.001). There was no effect of LA, ALA, or the PPARγ agonist rosiglitazone (1μM), but the effect of HODEs was replicated with apoptosis‐inducer camptothecin (10μM). Only 9‐HODE increased DNA fragmentation. The pro‐apoptotic effect of HODEs was blocked by the caspase inhibitor DEVD‐CHO. The PPARγ antagonist T0070907 further increased apoptosis, suggestive of the PPARγ‐regulated apoptotic effects induced by 9‐HODE. The use of siRNA for GPR132 showed no evidence that the effect of HODEs was mediated through this receptor. 9‐HODE and 13‐HODE are potent—and specific—regulators of apoptosis in THP‐1 cells. Their action is PPARγ‐dependent and independent of GPR132. Further studies to identify the signalling pathways through which HODEs increase apoptosis in macrophages may reveal novel therapeutic targets for atherosclerosis. 相似文献
82.
Jiri Hajek Tomas Jurena Bernhard Baier Arash Bagherzadeh Tom Schnick Quido Smejkal 《化学,工程师,技术》2015,87(7):991-997
Calcination of diatomite is an expensive process frequently resulting in products with unpredictable structure. Alternatively, calcination in swirling flow is an energy‐saving option. Computational fluid dynamics modeling of an experimental calcination process unit is presented. Experimental results and systematic collection of process data were used to define boundary condition for steady‐state and transient simulation runs. The comparison of experimental and simulation results shows the complexity of the calcination process. The results can be used for further process optimization. 相似文献
83.
MA‐NOTMP: A Triazacyclononane Trimethylphosphinate Based Bifunctional Chelator for Gallium Radiolabelling of Biomolecules 下载免费PDF全文
Sophie Poty Dr. Pauline Désogère Dr. Jakub Šimeček Dr. Claire Bernhard Dr. Victor Goncalves Dr. Christine Goze Dr. Frédéric Boschetti Dr. Johannes Notni Prof. Dr. Hans J. Wester Prof. Dr. Franck Denat 《ChemMedChem》2015,10(9):1475-1479
In the past few years, gallium‐68 has demonstrated significant potential as a radioisotope for positron emission tomography (PET), and the optimization of chelators for gallium coordination is a major goal in the development of radiopharmaceuticals. Methylaminotriazacyclononane trimethylphosphinate (MA‐NOTMP), a new C‐functionalized triazacyclononane derivative with phosphinate pendant arms, presents excellent coordination properties for 68Ga (low ligand concentration, labelling at low pH even at room temperature). A “ready‐to‐be‐grafted” bifunctional chelating agent (p‐NCS‐Bz‐MA‐NOTMP) was prepared to allow 68Ga labelling of sensitive biological vectors. Conjugation to a bombesin(7–14) derivative was performed, and preliminary in vitro experiments demonstrated the potential of MA‐NOTMP in the development of radiopharmaceuticals. This new chelator is therefore of major interest for labelling sensitive biomolecules, and further in vivo experiments will soon be performed. 相似文献
84.
Bernhard Ostrick Maximilian Fleischer Hans Meixner 《Journal of the American Ceramic Society》1997,80(8):2153-2156
Simultaneous Hall and conductivity measurements were performed in situ between 650° and 1050°C on n-type semiconducting BaSnO3 ceramics. The variation of the Hall mobility and the Hall carrier density as a function of oxygen partial pressure between 102 and 105 Pa and of temperature was investigated. At temperatures below 900°C the conductivity exhibits a dependence on temperature and oxygen partial pressure which is mainly determined by variations of the Hall mobility. Above 900°C most of the significant dependence is due to a variation in carrier density. Furthermore, a simple defect model assuming doubly ionized oxygen vacancies and acceptor impurities is discussed for BaSnO3 . 相似文献
85.
Sabrina Reich Dr. Hans Wolfgang Hoeffken Dr. Bettina Rosche Dr. Bettina M. Nestl Prof. Dr. Bernhard Hauer 《Chembiochem : a European journal of chemical biology》2012,13(16):2400-2407
The crystal structure of the “ene” nicotinamide‐dependent cyclohexenone reductase (NCR) from Zymomonas mobilis (PDB ID: 4A3U) has been determined in complex with acetate ion, FMN, and nicotinamide, to a resolution of 1.95 Å. To study the activity and enantioselectivity of this enzyme in the bioreduction of activated α,β‐unsaturated alkenes, the rational design methods site‐ and loop‐directed mutagenesis were applied. Based on a multiple sequence alignment of various members of the Old Yellow Enzyme family, eight single‐residue variants were generated and investigated in asymmetric bioreduction. Furthermore, a structural alignment of various ene reductases predicted four surface loop regions that are located near the entrance of the active site. Four NCR loop variants, derived from loop‐swapping experiments with OYE1 from Saccharomyces pastorianus, were analysed for bioreduction. The three enzyme variants, P245Q, D337Y and F314Y, displayed increased activity compared to wild‐type NCR towards the set of substrates tested. The active‐site mutation Y177A demonstrated a clear influence on the enantioselectivity. The loop‐swapping variants retained reduction efficiency, but demonstrated decreased enzyme activity compared with the wild‐type NCR ene reductase enzyme. 相似文献
86.
Guang Mei Wu Bernhard Schartel Malte Kleemeier Andreas Hartwig 《Polymer Engineering and Science》2012,52(3):507-517
Tetraphenylphosphonium modified layered silicate epoxy nanocomposite (EP/TPPMMT) combined with low‐melting silicate glass, Ceepree (CP) is investigated by thermal analysis, flammability tests and cone calorimeter at different heat fluxes. Adding CP and TPPMMT does not change the pyrolysis apart from increasing inorganic residue. The total heat evolved (THE) is changed insignificantly, as neither relevant additional carbonaceous charring nor flame inhibition occurs. However, flame retardancy is clearly observed due to an inorganic‐carbonaceous surface protection layer. The peak heat released rate (PHRR) is reduced by around 32–42% when 5 wt% TPPMMT is added, and 51–63% when 10 wt% CP is added. PHRR reduction less than expected is observed when both additives are combined. The reduction is greater than that achieved by using TPPMMT but less than when only CP is used. The morphology of fire residue is investigated by scanning electron microscope on different length scales and turns out to be the key to understanding the efficiency of flame retardancy. The fire residue of EP/CP shows a layered structure, whereas separated columns limit the barrier properties for EP/5%TPPMMT on the micrometer scale. Columns dominating the fire residue structure of EP/5%TPPMMT/10%CP deteriorate the fire retardancy, whereas a more integral structure at the top of the residue causes the improvement over EP/5%TPPMMT. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers 相似文献
87.
Daniela Mileva René Androsch Evgeny Zhuravlev Christoph Schick Bernhard Wunderlich 《Polymer》2012,53(2):277-282
Differential fast scanning chip calorimetry has been employed to study nucleation/ordering during annealing the glass of quenched isotactic polypropylene. Initially non-ordered samples were annealed below the glass transition temperature for different periods of time, and the change of structure during isothermal annealing was then analyzed by monitoring the exchange of latent heat on heating. Primary result of this work is the proof of homogeneous nucleation of ordering and mesophase formation in the glassy state. It is suggested that only local non-cooperative mobility of molecular segments is required to form small, ordered domains, and that the classical nucleation theory, which restricts nucleation of the crystallization/ordering process of polymers to temperatures between the equilibrium melting temperature and the glass transition temperature, needs modification. 相似文献
88.
ABSTRACT: : We report that porous silicon acoustic Bragg reflectors and AlN-based transducers can be successfully combined and processed in a commercial solidly mounted resonator production line. The resulting device takes advantage of the unique acoustic properties of porous silicon in order to form a monolithically integrated bulk acoustic wave resonator. 相似文献
89.
J Amonkosolpan D Wolverson B Goller S Polisski D Kovalev M Rollings MD Grogan TA Birks 《Nanoscale research letters》2012,7(1):397
ABSTRACT: Silicon nanoparticles of three types (oxide-terminated silicon nanospheres, micron-sized hydrogen-terminated porous silicon grains and micron-size oxide-terminated porous silicon grains) were incorporated into silica aerogels at the gel preparation stage. Samples with a wide range of concentrations were prepared, resulting in aerogels that were translucent (but weakly coloured) through to completely opaque for visible light over sample thicknesses of several millimetres. The photoluminescence of these composite materials and of silica aerogel without silicon inclusions was studied in vacuum and in the presence of molecular oxygen in order to determine whether there is any evidence for non-radiative energy transfer from the silicon triplet exciton state to molecular oxygen adsorbed at the silicon surface. No sensitivity to oxygen was observed from the nanoparticles which had partially H-terminated surfaces before incorporation and so we conclude that the silicon surface has become substantially oxidised. Finally, the FTIR and Raman scattering spectra of the composites were studied in order to establish the presence of crystalline silicon; by taking the ratio of intensities of the silicon and aerogel Raman bands, we were able to obtain a quantitative measure of the silicon nanoparticle concentration independent of the degree of optical attenuation. 相似文献
90.
Böhm M Kühl T Hardes K Coch R Arkona C Schlott B Steinmetzer T Imhof D 《ChemMedChem》2012,7(2):326-333
Tridegin, a 66‐mer peptide isolated from the leech Haementeria ghilianii, is a potent inhibitor of the coagulation factor XIIIa. This paper describes the chemical synthesis of tridegin by two different strategies—solid‐phase assembly and native chemical ligation—both followed by oxidation in solution phase. Tridegin and truncated analogues were examined for their activity and revealed a particular importance of the C‐terminal region of the parent peptide. Based on these studies a minimal sequence required for factor XIIIa inhibition could be identified. Our data revealed that the glutamine residue at position 52 (Q52) of tridegin most likely binds to the active site of factor XIIIa and was therefore suggested to react with the enzyme. The function of the N‐terminal region is also discussed, as the isolated C‐terminal segment of tridegin lost its inhibitory activity rapidly in the presence of factor XIIIa, whereas this was not the case for the full‐length inhibitor. 相似文献