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71.
Andrea Harrer Peter Wipfler Georg Pilz Katrin Oppermann Elisabeth Haschke-Becher Shahrzad Afazel J?rg Kraus Eugen Trinka Johann Sellner 《International journal of molecular sciences》2015,16(9):21832-21845
Fingolimod, an oral sphingosine 1-phosphate (S1P) receptor modulator, is approved for the treatment of relapsing forms of multiple sclerosis (MS). The interference with S1P signaling leads to retention particularly of chemokine receptor-7 (CCR7) expressing T cells in lymph nodes. The immunological basis of varicella zoster virus (VZV) infections during fingolimod treatment is unclear. Here, we studied the dynamics of systemic and intrathecal immune responses associated with symptomatic VZV reactivation including cessation of fingolimod and initiation of antiviral therapy. Key features in peripheral blood were an about two-fold increase of VZV-specific IgG at diagnosis of VZV reactivation as compared to the previous months, a relative enrichment of effector CD4+ T cells (36% versus mean 12% in controls), and an accelerated reconstitution of absolute lymphocytes counts including a normalized CD4+/CD8+ ratio and reappearance of CCR7+ T cells. In cerebrospinal fluid (CSF) the lymphocytic pleocytosis and CD4+/CD8+ ratios at diagnosis of reactivation and after nine days of fingolimod discontinuation remained unchanged. During this time CCR7+ T cells were not observed in CSF. Further research into fingolimod-associated VZV reactivation and immune reconstitution is mandatory to prevent morbidity and mortality associated with this potentially life-threatening condition. 相似文献
72.
Zhirong Liao Dragos Axinte Maxime Mieszala Rachid M’Saoubi Johann Michler Mark Hardy 《CIRP Annals》2018,67(1):109-112
Whilst gamma prime (γ′) phase is the strengthening phase in Ni-based superalloys its influence on machining has been seldom investigated. This paper reports for the first time on the effect of γ′ upon machining of Ni-based superalloys when cutting with parameters yielding different cutting temperature intervals which lead to strengthening/softening effects on the workpiece (sub)surface. In-depth XRD, SEM/FIB, EBSD analysis and unique micro-pillar testing in the workpiece superficial layers indicated that with the increase of γ′ fraction the grain plastic deformation significantly decreased, while specific cutting energy can switch from low to high values influenced by the real cutting temperature. 相似文献
73.
74.
Patrick Huber Kurt Kratzer Tobias Huber Michael Kleiser Johann Kollegger 《Beton- und Stahlbetonbau》2016,111(11):706-715
Assessment of the shear strength of an existing post‐tensioned concrete bridge with a low amount of shear reinforcement – First application of the ”Flexural Shear Crack“ model in practice In recent years it was reported several times, that within a static assessment according to current standards the shear strength of post‐tensioned bridges, which were built in Austria before 1989, cannot be fulfilled any more. However, test results prove, that especially prestressed structures have additional load bearing capacities, which cannot be reproduced with current calculation models. In the framework of a pilot project a new developed shear model (Flexural Shear Crack Model) was used. In this paper the approach as well as the main results of a statical reevaluation of an existing post‐tensioned road bridge at the Tauern Autobahn A10 will be presented. 相似文献
75.
Alois Vorwagner Stefan L. Burtscher Günter Grass Johann Kollegger 《Beton- und Stahlbetonbau》2010,105(1):9-18
Oberflächig geklebte Kohlefaserlamellen (CFK) werden seit vielen Jahren zur Bauteilverstärkung eingesetzt. Die hohe Festigkeit dieser Lamellen kann aufgrund der begrenzten Zugkapazität des Betons nicht zur Gänze ausgenutzt werden. Eingeschlitzte CFK Lamellen hingegen bieten wesentliche Vorteile, die zusammen mit Vorspannung noch weiter optimiert werden können. Für den Vorspannvorgang wurde eine spezielle Verankerung, auf Basis der Composite Wedge Technik, entwickelt, die einfaches und rasches Vorspannen erlaubt. Die Verankerung ist zudem nur 8 kg schwer, was besonders vorteilhaft beim Hantieren an der Tragwerksunterseite ist. Nach dem Vorspannen wird die Verankerung entfernt, die permanente Verankerung der Lamellenenden wird durch nachträgliches Verkleben gewährleistet. Es verbleiben keine Stahlteile im oder am Bauwerk. So zeichnet sich die Konstruktion durch geringen Wartungsaufwand und hohe Dauerhaftigkeit aus. Die Effizienz der entwickelten Systeme wurde an vorgespannten Plattenstreifen experimentell untersucht. In den Untersuchungen konnte die Funktionsfähigkeit nachgewiesen werden. Strengthening using Prestressed Near Surface Mounted Strips Exernally bonded carbon fiber reinforced plastic (CFRP) strips are used since several years for strengthening of structures. The high strength of the strips cannot be exploited in most applications. Near surface mounted strips offer several advantages, which allow for further optimization together with prestressing. For the prestressing action a special anchoring device, based on the Composite Wedge Principle, was developed, which allows a simple and quick prestressing procedure. Additionally the anchorage weighs only 8 kg, which is especially beneficial when manipulations on the lower surface of the structure are necessary. The anchorage will be removed after prestressing and the permanent anchorage of the ends of the strips will be established by bond. No steel parts remain in the structure, after completing the strengthening. This results in low maintenance and a high durability. The efficiency of the developed systems and the prestressed plate strips was examined experimentally. In these investigations a perfect functionality could be demonstrated. 相似文献
76.
New directives of the European Union require operators of waste-to-energy (WTE) plants to report the amount of electricity that is produced from renewable sources in the waste feed. Until now, the standard method to determine the portion of renewable electricity is sorting the wastes into defined fractions of fossil organic and biogenic waste components and determining the lower heating value of these fractions. Out of it the amount of electricity production from renewables is calculated. This practice is labor and cost intensive. Therefore, it is usually carried out once a year which provides only a snapshot analysis of limited significance. This paper proposes a method to calculate the portion of electricity produced from renewable materials in waste continuously by solving a set of equations. All data required are either available from literature or from operating data routinely measured in WTE plants. The advantages are statistically derived uncertainty of the result, temporal resolution of the result down to daily mean values, low implementation efforts, and virtually no operational costs. An example of the implementation of the method to a 60 000 tons per year WTE plant is given. 相似文献
77.
78.
A copolymer comprising of 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS®) and itaconic acid (molar ratio 1 : 0.32) was synthesized by aqueous free radical polymerization and probed as high temperature retarder for oil well cement. Characteristic properties of the copolymer including molar masses (Mw and Mn), polydispersity index and anionic charge amount were determined. The copolymer possesses a Mw of ~ 2 × 105 g/mol and is highly anionic. HT/HP consistometer tests confirmed effectiveness of the retarder at temperatures up to 200°C. The working mechanism of NaAMPS®‐co‐itaconic acid was found to rely exclusively on its huge calcium binding capacity (5 g calcium/g copolymer). It reduces the amount of freely dissolved, nonbound calcium ions present in cement pore solution and thus hinders the growth of cement hydrates because of lack of calcium. The value for the calcium binding capability is 46 times higher than the stoichiometric amount per ? COO? functionality. Consequently, calcium also coordinates to other donor atoms present in the retarder. NaAMPS®‐co‐itaconic acid also adsorbs onto cement, as was evidenced by TOC analysis of cement filtrates, zeta potential measurement and decreased rheology of cement pastes. However, adsorption plays no role in the retarding mechanism of this copolymer. Combination of NaAMPS®‐co‐itaconic acid retarder with a common CaAMPS®‐co‐NNDMA fluid loss additive (FLA) revealed that competitive adsorption on cement between these two admixtures occurs. The retarder fills interstitial adsorption sites on cement located between those occupied by the larger FLA molecules. In consequence, fewer amounts of CaAMPS®‐co‐NNDMA can adsorb and its effectiveness is reduced. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
79.
The secondary diamine 1,3,5,7-tetrahydro[1,2c:4,5c'] benzodipyrrole (3) and 1,2,4,5-tetrabromomethylbenzene (1) form a polymeric ionene with spirane structure through a repetitive alkylation reaction. The structure of the product could be proven by13C-NMR spectroscopy by comparison with suitable reference compounds. Solutions in aqueous methanol exhibit a typical polyelectrolyte effect. Variation of the counterions produces sufficient solubility in organic solvents. From the crystal structure of a similar model compound one can conclude that the synthesized polymer has a rod-like shape. 相似文献
80.
For dynamically measuring position in three degrees of freedom laser tracking systems are well known. Up to now no possibility to measure also orientation using the same laser beam has been known. We present a technique to incorporate orientation measurement into a laser tracking system that requires only minor changes in the existing hardware. The method is based on the analysis of an image of the reflected laser beam intensity distribution. In this image the edges of a slightly modified retroreflector represent a function of the orientation of the end-effector holding the retroreflector. It is shown that from this image the orientation can be determined uniquely and in real time.
A laser tracking system including position and orientation measurement constitutes an instrument to accurately determine robot performance as well as to acquire hints on how to improve robot models and control algorithms. 相似文献