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Several Series (several + series)
Selected AbstractsMit Schrauben Bewehren , Neue ErgebnisseBAUTECHNIK, Issue 4 2009Martin Trautz Univ.-Prof. Holzbau; Baumechanik; Timber Construction; Structural Mechanics Abstract Selbstbohrende Vollgewindeschrauben ermöglichen wirkungsvolle Verstärkungen und Versteifungen sowie leistungsfähige Fügungen von Holzbauteilen. Dabei werden gezielt die hohe axiale Zugfestigkeit und Dehnsteifigkeit sowie der kontinuierliche Verbund der Schrauben genutzt, um ähnlich einer Bewehrung im Stahlbetonbau die schwachen Tragrichtungen des Holzes senkrecht und schräg zur Faserrichtung zu ertüchtigen. Die Bemessung der verschiedenen Schraubenkonfigurationen kann mit Hilfe der aus dem Stahlbetonbau bekannten Stabwerkmodelle erfolgen, die den inneren Kraftfluss im Bauteil bzw. im Anschluss nachbilden und eine einfache Dimensionierung der Schrauben ermöglichen. In mehreren Versuchsreihen mit Bauteilverstärkungen und -fügungen im Jahr 2007 an der RWTH Aachen konnte die erfolgreiche Anwendung dieses Konstruktionsprinzips gezeigt werden. Darauf aufbauend wurden in einem Fortsetzungsprojekt im Jahr 2008 veränderte und verfeinerte Schraubenkonfigurationen konstruiert und auf ihr Festigkeitsverhalten hin untersucht. Versuche an stahllamellenverstärkten Brettschichtholz-Trägern und biegesteifen Rahmenecken unter positiver und negativer Momentenbelastung zeigten eine hohe Leistungsfähigkeit, die das Potential der Methode nachdrücklich untermauert. Self-tapping screws as reinforcement , new results. Self-tapping continuously threaded screws can be used as elements for reinforcement or joints in timber construction because of their high axial strength and excellent bonding properties. The layout of the reinforcing or joining screws can be derived from strut-and-tiemodels which are common in concrete design and follow the internal flow of forces. Several series of tests in 2007 already showed the high potential of this construction method on various joint details and reinforced timber elements. Based on this success in 2008 further tests were taken out on joints and timber beams with altered and more sophisticated screw configurations. Hereby the load-bearing capacity of timber beams reinforced with steel lamellas and rigid frame corners connected with self-tapping screws was extraordinary and demonstrated once more the high potential of this design method. [source] Synthesis of Aromatase Inhibitors and Dual Aromatase Steroid Sulfatase Inhibitors by Linking an Arylsulfamate Motif to 4-(4H -1,2,4-triazol-4-ylamino)benzonitrile: SAR, Crystal Structures, in,vitro and in,vivo ActivitiesCHEMMEDCHEM, Issue 11 2008Christian Bubert Dr. Abstract 4-(((4-Cyanophenyl)(4H -1,2,4-triazol-4-yl)amino)methyl)phenyl sulfamate (6,a) was the first dual aromatase,sulfatase inhibitor (DASI) reported. Several series of its derivatives with various linker systems between the steroid sulfatase (STS) and the aromatase inhibitory pharmacophores were synthesised and evaluated in JEG-3 cells. The X-ray crystal structures of the aromatase inhibitors, DASI precursors 42,d and 60, and DASI 43,h were determined. Nearly all derivatives show improved in,vitro aromatase inhibition over 6,a but decreased STS inhibition. The best aromatase inhibitor is 42,e (IC50=0.26,nM) and the best DASI is 43,e (IC50,aromatase=0.45,nM, IC50,STS=1200,nM). SAR for aromatase inhibition shows that compounds containing an alkylene- and thioether-based linker system are more potent than those that are ether-, sulfone-, or sulfonamide-based, and that the length of the linker has a limited effect on aromatase inhibition beyond two methylene units. Compounds 43,d,f were studied in,vivo (10,mg,kg,1, single, p.o.). The most potent DASI is 43,e, which inhibited PMSG-induced plasma estradiol levels by 92,% and liver STS activity by 98,% 3,h after dosing. These results further strengthen the concept of designing and developing DASIs for potential treatment of hormone-related cancers. [source] Studies on 4,7-di-substitution effects of one ligand in [Ru(Phen)3]2 with DFT methodJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 4 2002Kangcheng Zheng Abstract Studies on the complex [Ru(phen)3]2+ (phen = 1,10-phenanthroline) and its derivatives with 4,7-di-substitution on one ligand(phen) were carried out using the DFT method at the B3LYP/LanL2DZ level of theory. The trends in the substituent effects caused by the electron-pushing group (OH) and the electron-withdrawing group (F), on the electronic structures and the related properties, for example, the energies and the components of some frontier molecular orbitals, the spectroscopy properties, and the net charge populations of some main atoms of the complexes, etc., have been investigated. The computational results show that the substituents have some interesting effects on the electronic structures and the related properties of the complexes. First, according to the analysis of components of LUMO of the complexes, the electron-withdrawing group (F) can activate the main ligand (the substituted ligand, i.e., 2R-phen) and passivate the coligands, on the contrary, the electron-pushing group (OH) can activate the coligands and passivate the main ligand in the first electronic excited states of complexes. Second, both the electron-pushing group (OH) and the electron-withdrawing group (F) can cause a red shift in the electronic ground bands. Third, the characteristics of the atomic net charge populations on the main ligand can also be analyzed in detail by means of a schematic map expressed by several series of arrowheads based on the law of polarity alternation and the idea of polarity interference. The most negative charges are populated on N1, the next most net negative charges are populated on C3 among the skeleton atoms for the three complexes, etc. The computational results can be better used to explain some experimental phenomena and trends. © 2002 Wiley Periodicals, Inc. J Comput Chem 4: 436,443, 2002; DOI 10.1002/jcc.10038 [source] Liquid-crystalline thermosets by the curing of dimeric liquid-crystalline epoxyimine monomers with 2,4-toluene diisocyanateJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2003David Ribera Abstract We studied the curing processes of several series of dimeric liquid-crystalline epoxyimine monomers with 2,4-toluene diisocyanate (TDI) alone or with added catalytic proportions of 4-(N,N -dimethylamino)pyridine. We obtained isotropic materials or liquid-crystalline thermosets with different degrees of order, which depended on the structures of the monomers. To fix ordered networks, we had to do the curing in two steps when TDI was used alone as the curing agent. However, when a tertiary amine was added in catalytic proportions, the ordered networks were fixed in just one step. In this way, we were able to fix both nematic and smectic mesophases. The significance of the polarization of the mesogen for obtaining liquid-crystalline thermosets was demonstrated. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2521,2530, 2003 [source] Indirect absorption edge of TlGaSe2 crystalsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 5 2006Vytautas Grivickas Abstract Absorption spectra of high-quality layered TlGaSe2 single crystals were measured in a wide temperature range. Results obtained at low temperatures show that the direct excitonic absorption initiating at EGdir = 2.127 eV is perturbed by several series of step-like features inherent for the indirect type transitions. Spectral modelling of these features revealed that: (i) the ground state of indirect exciton, n = 1, has a large Rydberg energy of about 100 meV, and (ii) the enhanced absorption to excited indirect excitonic states, n = 2, 3, exceeds the classical prediction for scaling factors K1ind/n3. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Monodisperse magnetic nanoparticles for biomedical applicationsPOLYMER INTERNATIONAL, Issue 7 2007Chenjie Xu Abstract Magnetic nanoparticles that are superparamagnetic with high saturation moment have great potential for biomedical applications. Solution-phase syntheses have recently been applied to make various kinds of monodisperse magnetic nanoparticles with standard deviation in diameter of less than 10%. However, the surface of these nanoparticles is coated with a layer of hydrocarbon molecules due to the use of lipid-like carboxylic acid and amine in the syntheses. Surface functionalization leads to the formation of water-soluble nanoparticles that can be further modified with various biomolecules. Such functionalization has brought about several series of monodisperse magnetic nanoparticle systems that have shown promising applications in protein or DNA separation, detection and magnetic resonance imaging contrast enhancement. The goal of this mini review is to summarize the recent progress in the synthesis and surface modification of monodisperse magnetic nanoparticles and their applications in biomedicine. Copyright © 2007 Society of Chemical Industry [source] AN ANALYSIS OF MONETARY POLICY SHOCKS IN JAPAN: A FACTOR AUGMENTED VECTOR AUTOREGRESSIVE APPROACH,THE JAPANESE ECONOMIC REVIEW, Issue 4 2007MASAHIKO SHIBAMOTO This paper analyses monetary policy shocks in Japan using a factor augmented vector autoregressive approach. There are three main findings. First, the time lags with which the monetary policy shocks are transmitted vary between the various macroeconomic time series. These include several series that have not been included thus far in standard vector autoregressive analysis, including housing starts and employment indices. Second, a coherent picture of monetary policy effects on the economy is obtained. Third, it is found that monetary policy shocks have a stronger impact on real variables, such as employment and housing starts, than industrial production. [source] Head and Neck Cancer: The Importance of Oxygen ,THE LARYNGOSCOPE, Issue 5 2000David J. Terris MD Abstract Objectives To use recently introduced polarographic technology to characterize the distribution of oxygenation in solid tumors, explore the differences between severe hypoxia and true necrosis, and evaluate the ability to predict treatment outcomes based on tumor oxygenation. Study Design Prospective, nonrandomized trial of patients with advanced head and neck cancer, conducted at an academic institution. Methods A total of 63 patients underwent polarographic oxygen measurements of their tumors. Experiment 1 was designed to determine whether a gradient of oxygenation exists within tumors by examining several series of measurements in each tumor. Experiment 2 was an analysis of the difference in data variance incurred when comparing oxygen measurements using oxygen electrodes of two different sizes. Experiment 3 compared the proportion of tumor necrosis to the proportion of very low (,2.5 mm Hg) polarographic oxygen measurements. Experiment 4 was designed to explore the correlation between oxygenation and treatment outcomes after nonsurgical management. Results No gradient of oxygenation was found within cervical lymph node metastases from head and neck squamous cell carcinomas (P > .9). Tumor measurements achieved with larger (17 ,m) electrodes displayed smaller variances than those obtained with smaller (12 ,m) electrodes, although this difference failed to reach statistical significance (P = .60). There was no correlation between tumor necrosis and the proportion of very low (,2.5 mm Hg) oxygen measurements. There was a nonsignificant trend toward poorer locoregional control and overall survival in hypoxic tumors. Conclusions Hypoxia exists within cervical lymph node metastases from head and neck squamous carcinomas, but the hypoxic regions are distributed essentially randomly. As expected, measurements of oxygen achieved with larger electrodes results in lowered variance, but with no change in overall tumor mean oxygen levels. Polarographic oxygen measurements are independent of tumor necrosis. Finally, oxygenation as an independent variable is incapable of predicting prognosis, probably reflecting the multifactorial nature of the biological behavior of head and neck cancers. [source] Crystal Structure Analysis and in Silico pKa Calculations Suggest Strong pKa Shifts of Ligands as Driving Force for High-Affinity Binding to TGTCHEMBIOCHEM, Issue 4 2009Tina Ritschel Abstract Expandedlin -benzoguanines exhibit binding affinities to tRNA-guanine transglycosylase (TGT) in the low-nanomolar range. A significant pKa shift is observed for the inhibitors moving from aqueous solution to protein environment. The protonation of the inhibitor facilitates a charge-assisted hydrogen bond in the protein,ligand complex. A novel ligand series is presented to inhibit tRNA-guanine transglycosylase (TGT), a protein with a significant role in the pathogenicity mechanism of Shigella flexneri, the causative agent of Shigellosis. The enzyme exchanges guanine in the wobble position of tRNAAsn,Asp,His,Tyr against a modified base. To prevent the base-exchange reaction, several series of inhibitors have already been designed, synthesized, and tested. One aim of previous studies was to address a hydrophobic pocket with different side chains attached to the parent skeletons. Disappointingly, no significant increase in binding affinity could be observed that could be explained by the disruption of a conserved water cluster. The ligand series examined in this study are based on the known scaffold lin -benzoguanine. Different side chains were introduced leading to 2-amino- lin -benzoguanines, which address a different pocket of the protein and avoid disruption of the water cluster. With the introduction of an amino group in the 2-position, a dramatic increase in binding affinity can be experienced. To explain this significant gain in binding affinity, Poisson,Boltzmann calculations were performed to explore pKa changes of ligand functional groups upon protein binding, they can differ significantly on going from aqueous solution to protein environment. For all complexes, a permanent protonation of the newly designed ligands is suggested, leading to a charge-assisted hydrogen bond in the protein,ligand complex. This increased strength in hydrogen bonding takes beneficial effect on binding affinity of the ligands, resulting in low-nanomolar binders. Crystal structures and docking emphasize the importance of the newly created charge-assisted hydrogen bond. A detailed analysis of the crystal structures in complex with substituted 2-amino- lin -benzoguanines indicate pronounced disorder of the attached side chains addressing the ribose 33 binding pocket. Docking suggests multiple orientations of these side chains. Obviously, an entropic advantage of the residual mobility experienced by these ligands in the bound state is beneficial and reveals an overall improved protein binding. [source] | |||||||||||||