Bemessung von Grundbauwerken aus Stahlbeton nach DIN 1054 (01.03)

Design of Foundation Construction made of Reinforced Concrete according to DIN 1054 (01.03) Other than the idea given in DIN 1054 (draft november 1976) the scope of the revised draft of january 2003 clearly also refers to the stability as well as the serviceability of construction and structural members concerning ground and foundation work. However, the design concepts proposed in this contribution, do not completely correspond to other regulations of the new “Generation of Standards”, in particular to the rules for the design of concrete structural members (DIN 1045‐1, part 1‐4, DIN 1055‐100, DIN Fachberichte 100‐104). This leads to interpretation possibilities for the interface between both standards. In the following the main features and differences of both standards are introduced and application rules are proposed. Furthermore, the application of the new “Generation of Standards” is presented within the example of a tunnel structure in mining construction. These results are compared to the results according to the standards which have been valid so far (DIN 1045 (07.88), DIN 1054 (11.76), ZTV‐Tunnel part I).     

Localization and map building using laser range sensors in outdoor applications

This paper presents the design of a high accuracy outdoor navigation system based on standard dead reckoning sensors and laser range and bearing information. The data validation problem is addressed using laser intensity information. The beacon design aspect and location of landmarks are also discussed in relation to desired accuracy and required area of operation. The results are important for simultaneous localization and map building applications (SLAM), since the feature extraction and validation are resolved at the sensor level using laser intensity. This facilitates the use of additional natural landmarks to improve the accuracy of the localization algorithm. The modelling aspects to implement SLAM with beacons and natural features are also presented. These results are of fundamental importance because the implementation of the algorithm does not require the surveying of beacons. Furthermore we demonstrate that by using natural landmarks accurate localization can be achieved by only requiring the initial estimate of the position of the vehicle. The algorithms are validated in outdoor environments using a standard utility car retrofitted with the navigation sensors and a 1 cm precision Kinematic GPS used as ground truth. © 2000 John Wiley & Sons, Inc.     

Influence of the component reactivity on the properties of ternary reactive blends Nylon 6/rigid brittle polymer/elastomer

The ternary reactive blend of Nylon 6 matrix with dispersed poly(styrene‐co‐maleic anhydride) and maleated SEBS or EPR represents a toughened system with enhanced strength and, at least, the retained stiffness of the matrix. In the present work, the influence of changed reactivity of dispersed phases, including the application of one or both nonreactive components, on the phase structure and related mechanical behavior is studied. Lowering of the reactivity of the elastomer caused a decrease of blend properties, whereas suitable dilution of SMA by PS brought better properties in comparison with a fully reactive system. With the nonreactive N6/PS/SEBS blend, the formation of blended bicontinuous inclusions causes worsening of toughness. This documents the importance of separate dispersion of both phases for good mechanical behavior in the system studied, which is shown to be assured by application of at least one reactive component. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1597–1603, 2000     

Strukturvariationen durch Reaktionen der Thiocarbonylgruppe

Structural Variations by Reactions of the Thiocarbonyl Group The 2,3‐dihydrothiazol‐2‐thiones 1a—c have been methylated to the 2‐methylsulfanylthiazolium iodides 2a—c , which could be reacted with double activated CH‐acidic compounds like 4‐nitrophenylacetonitrile ( 3 ) to yield 5 and 6a,b , with malonic acid derivatives 7a—c to yield the push pull substituted ketene‐S,N‐acetales 8a—c or with 3‐aminorhoda‐nine derivatives to yield 12a,b . Vinylogous CH‐acidic compounds like 9a—d reacted with 2b to the push‐pull substituted butadienes 10a—d . With p‐phenethidine 2b formed depending on the reaction conditions either the rare structure of an ortho‐dithiocarbonic diester diamide ( 14 ) or the isothiourea 15 . With hydrazino compounds, 16a—c with hydrazono partial structure resulted. Efforts to acylate the unsubstituted nitrogen of 17 with carbonic acid ester derivatives always yielded the S‐acylated products 18 and 20a,b .     

Catalytic Promiscuity of cGAS: A Facile Enzymatic Synthesis of 2′-3′-Linked Cyclic Dinucleotides

Cyclic GMP-AMP synthase (cGAS) is a cytosolic DNA sensor that catalyzes the synthesis of the cyclic GMP-AMP dinucleotide 2′3′-cGAMP. 2′3′-cGAMP functions as inducer for the production of type I interferons. Derivatives of this important second messenger are highly valuable for pharmaceutical applications. However, the production of these analogues requires complex, multistep syntheses. Herein, human cGAS is shown to react with a series of unnatural nucleotides, thus leading to novel cyclic dinucleotides. Most substrate derivatives with modifications at the nucleobase, ribose, and the α-thio phosphate were accepted. These results demonstrate the catalytic promiscuity of human cGAS and its utility for the biocatalytic synthesis of cyclic dinucleotide derivatives.     

Aramid pulp reinforced hydrogenated nitrile butadiene rubber composites with ionic liquid compatibilizers

Although carbon black is an effective reinforcement for most rubbers, its replacement by other fillers would be beneficial. Aramid fibers are used in a range of applications in the rubber industry, providing dimensional stability prior to vulcanization and improving the mechanical properties of the elastomeric product. Nevertheless, their relatively inert surface is an obstacle in the exploitation of their full potential. In this work, two ionic liquids were investigated as compatibilizers in the preparation of hydrogenated nitrile butadiene rubber composites with aramid pulp and carbon black fillers. The materials were characterized using swelling, hardness and tensile tests, differential scanning calorimetry, thermal gravimetric analysis, and infrared spectroscopy. The carbon black-free composite prepared from aramid pulp treated with 1.0 wt% of 1-carboxymethyl-3-methylimidazolium chloride outperformed all other studied materials, presenting a higher modulus at 100% strain (7.31 MPa), while maintaining high strain at break. Thus, ionic liquids were found to potentialize the aramid reinforcement effect in these rubber composites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48702.     

Processing sequence and the properties of vinyl compounds

Acid-base interaction parameters were measured by inverse gas chromatography over broad temperature ranges for Poly(vinyl chloride), plasticizer, and CaCO₃ fillers. Mixing was performed by three routes. In one, all components were added simultaneously, while in others two of the components were premixed, the third ingredient being added subsequently. Mixing was carried on to equilibrium torque readings. The energy requirement for mixing was found to depend on the interaction balance among the components, and to vary with the procedure selected. Minimum requirement was associated with the simultaneous introduction of all ingredients. Higher energies were needed in sequential mixing schemes, presumably because equilibrium partitioning of components was hindered in these instances. Initial mechanical properties of the compounds did not vary greatly with preparation procedure, but upon aging, mechanical property variations became quite evident. Component repartitioning, driven by shifting interaction balances at aging and at test (room) temperatures are cited as responsible. The kinetics of attaining equilibrium mechanical properties also were found to vary with mixing procedure and to respond to the interaction balance concept.     

Mitochondrial Toxicity Associated with Imatinib and Sorafenib in Isolated Rat Heart Fibers and the Cardiomyoblast H9c2 Cell Line

Tyrosine kinase inhibitors (TKIs) are associated with cardiac toxicity, which may be caused by mitochondrial toxicity. The underlying mechanisms are currently unclear and require further investigation. In the present study, we aimed to investigate in more detail the role of the enzyme complexes of the electron transfer system (ETS), mitochondrial oxidative stress, and mechanisms of cell death in cardiac toxicity associated with imatinib and sorafenib. Cardiac myoblast H9c2 cells were exposed to imatinib and sorafenib (1 to 100 µM) for 24 h. Permeabilized rat cardiac fibers were treated with both drugs for 15 min. H9c2 cells exposed to sorafenib for 24 h showed a higher membrane toxicity and ATP depletion in the presence of galactose (favoring mitochondrial metabolism) compared to glucose (favoring glycolysis) but not when exposed to imatinib. Both TKIs resulted in a higher dissipation of the mitochondrial membrane potential in galactose compared to glucose media. Imatinib inhibited Complex I (CI)- and CIII- linked respiration under both conditions. Sorafenib impaired CI-, CII-, and CIII-linked respiration in H9c2 cells cultured with glucose, whereas it inhibited all ETS complexes with galactose. In permeabilized rat cardiac myofibers, acute exposure to imatinib and sorafenib decreased CI- and CIV-linked respiration in the presence of the drugs. Electron microscopy showed enlarged mitochondria with disorganized cristae. In addition, both TKIs caused mitochondrial superoxide accumulation and decreased the cellular GSH pool. Both TKIs induced caspase 3/7 activation, suggesting apoptosis as a mechanism of cell death. Imatinib and sorafenib impaired the function of cardiac mitochondria in isolated rat cardiac fibers and in H9c2 cells at plasma concentrations reached in humans. Both imatinib and sorafenib impaired the function of enzyme complexes of the ETS, which was associated with mitochondrial ROS accumulation and cell death by apoptosis.     

Lipid,sterol and fatty acid composition of antarctic krill (Euphausia superba Dana)

The lipid classes, fatty acids of total and individual lipids and sterols of Antarctic krill (Euphausia superba Dana) from two areas of the Antarctic Ocean were analyzed by thin layer chromatography (TLC), gas liquid chromatography (GLC) and gas liquid chromatography/mass spectrometry (GLC/MS). Basic differences in the lipid composition of krill from the Scotia Sea (caught in Dec. 1977) and krill from the Gerlache Strait (caught in Mar. 1981) were not observed. The main lipid classes found were: phosphatidylcholine (PC) (33–36%), phosphatidylethanolamine (PE) (5–6%), triacylglycerol (TG) (33–40%), free fatty acids (FFA) (8–16%) and sterols (1.4–1.7%). Wax esters and sterol esters were present only in traces. More than 50 fatty acids could be identified using GLC/MS, the major ones being 14∶0, 16∶0, 16∶1(n−7), 18∶1(n−9), 18∶1(n−7), 20∶5(n−3) and 22∶6(n−3). Phytanic acid was found in a concentration of 3% of total fatty acids. Short, medium-chain and hydroxy fatty acids (C≤10) were not detectable. The sterol fraction consisted of cholesterol, desmosterol and 22-dehydrocholesterol.     

Electrochemical studies on nanofiller incorporated poly(vinylidene fluoride–hexafluoropropylene) (PVdF–HFP) composite electrolytes for lithium batteries

Composite polymer electrolytes (CPE), comprising poly(vinylidene fluoride–hexafluoropropylene) (PVdF–HFP), aluminum oxyhydroxide, (AlO[OH] _n – of 40 nm and 7 μm) as filler and LiN(C₂F₅SO₂)₂ or LiClO₄ as lithium salt were prepared using a solution casting technique. The membranes were subjected to XRD, impedance spectroscopy, compatibility and transport number studies. The incorporation of nanofiller greatly enhanced the ionic conductivity and the compatibility of the composite polymer electrolyte. The electrochemical properties of CPE with nano sized fillers are better than those of micron size. Charge- discharge studies of Li Cr_0.01Mn_1.99O₄/CPE/Li cells were made at 70 °C and are discussed.