Improvement of utero-placental perfusion by transcutaneous nerve stimulation (author's transl)

A report is given on 37 patients with a diminished utero-placental perfusion. 12 patients underwent only once, 25 patients daily over 2 to 3 weeks a transcutaneous lumbo-sacral electric nerve stimulation. Both, the 12 patients stimulated only once and the 25 patients with daily stimulation, showed a significant increase of utero-placental perfusion measured by the method of radioisotope placental perfusion. Transcutaneous nerve stimulation (TNS) therefore could be used for therapeutic purpose in cases of placental dysfunction.     

Improvement of accuracy in determining flow stress in hot upsetting tests

Knowledge of correct flow stress curves of steel at high temperatures is of essential importance for reliable plasto-mechanical simulations in materials processing and for an effective planning and designing of industrial hot forming schedules. Error considerations of flow curve determinations allow an estimation of the quality of flow curves. The experiments are performed on a computer controlled servo-hydraulic test maschine. Flow stress errors are calculated as a function of geometry deviations (due to thermal expansion, scaling, predeformation and inaccuracies in specimen geometry), temperature and strain rate deviations. The influence of friction and initial microstructure on flow curves have to be considered. Metal flow can be improved by using a suitable specimen geometry and lubricants. Thermal treatment before testing has to provide a microstructure, similar to the real structure of the material. Different initial microstructures (from varying thermal treatments) influence the overall magnitude of the flow stress curve. Using the flow stress data in a rolling simulation programme the effects on forming loads and torques are analysed.     

Binding of ²³⁹Pu and ⁹⁰Sr to organic colloids in soil solutions: evidence from a field experiment

Colloidal transport has been shown to enhance the migration of plutonium in groundwater downstream from contaminated sites, but little is known about the adsorption of ??Sr and plutonium onto colloids in the soil solution of natural soils. We sampled soil solutions using suction cups, and separated colloids using ultrafiltration to determine the distribution of 23?Pu and ??Sr between the truly dissolved fraction and the colloidal fraction of the solutions of three Alpine soils contaminated only by global fallout from the nuclear weapon tests. Plutonium was essentially found in the colloidal fraction (>80%) and probably associated with organic matter. A significant amount of colloidal ??Sr was detected in organic-rich soil solutions. Our results suggest that binding to organic colloids in the soil solutions plays a key role with respect to the mobility of plutonium in natural alpine soils and, to a lesser extent, to the mobility of ??Sr.     

Testing for a break in persistence under long-range dependencies

Abstract.  We show that tests for a break in the persistence of a time series in the classical I (0)/ I (1) framework have serious size distortions when the actual data-generating process (DGP) exhibits long-range dependencies. We prove that the limiting distribution of a CUSUM of squares-based test depends on the true memory parameter if the DGP exhibits long memory. We propose adjusted critical values for the test and give finite sample response curves that allow easy implementation of the test by the practitioner and also ease in computing the relevant critical values. We furthermore prove the consistency of the test for a simple breakpoint estimator also under long memory. We show that the test has satisfying power properties when the correct critical values are used.     

Verbundlose interne Vorspannung von weitgespannten Plattentragwerken im Hochbau

Internal unbounded Posttensioning in Wide Span Slabs for Building Constructions In order to comply with the needs of robustness and economy to be considered in design and construction, the internal, unbounded posttensioning has been optimized, in a way to install the cables with the minimum necessary amount of work. For this purpose a free system of posttensioning cables has been adopted, in which border uplift forces (in correspondence of the supports) and single or multiple midspan uplift forces are necessary. The deviation forces helps to limit the deflections and cracks. In this paper after some theoretical reflections two innovative practical applications are presented. On the basis of the mechanics of the load bearing behaviour and with three dimensional finite element calculations also the soil‐structure interaction have been taken into account.     

In vitro cytotoxicity of oxide nanoparticles: comparison to asbestos, silica, and the effect of particle solubility

Early indicators for nanoparticle-derived adverse health effects should provide a relative measure for cytotoxicity of nanomaterials in comparison to existing toxicological data. We have therefore evaluated a human mesothelioma and a rodent fibroblast cell line for in vitro cytotoxicity tests using seven industrially important nanoparticles. Their response in terms of metabolic activity and cell proliferation of cultures exposed to 0-30 ppm nanoparticles (microg g(-1)) was compared to the effects of nontoxic amorphous silica and toxic crocidolite asbestos. Solubility was found to strongly influence the cytotoxic response. The results further revealed a nanoparticle-specific cytotoxic mechanism for uncoated iron oxide and partial detoxification or recovery after treatment with zirconia, ceria, or titania. While in vitro experiments may never replace in vivo studies, the relatively simple cytotoxic tests provide a readily available pre-screening method.     

3D‐Printing of High‐κ Thiol‐Ene Resins with Spiro‐Orthoesters as Anti‐Shrinkage Additive

Tri(ethylene glycol) divinyl ether and the spiro‐orthoester 2‐((allyloxy)methy)‐1,4,6‐trioxospiro[4.4]nonane can be formulated in different ratios and crosslinked by thiol‐ene reactions. The spiro‐orthoester is used as anti‐shrinkage additive, enabling shrinkage reduction of up to 39%. Addition of a radical photoinitiator for the thiol‐ene reaction and a cationic photoinitiator for the double ring‐opening of the spiro‐orthoester enables dual‐curing for application in 3D‐printing. The formulation free of the spiro‐orthoester shows gelation during the printing process and, correspondingly, low resolution. The formulations containing the spiro‐orthoester exhibit higher resolutions in the range of 50 µm. The resins containing mixtures of tri(ethylene glycol) divinyl ether and the spiro‐orthoester show permittivities as high as 10⁴. The dielectric loss factor of the resins is in the range of 0.5–7.6, and the conductivity in the range of 1.3?10^?11 to 2.0?10^?11 S cm^?1. These high‐κ materials can be 3D‐printed by digital light processing for the next generation of electronic materials.     

Inhibition of Hepatitis C Replication by Targeting the Molecular Chaperone Hsp90: Synthesis and Biological Evaluation of 4,5,6,7-Tetrahydrobenzo[1,2-d]thiazole Derivatives

Cellular chaperones that belong to the heat-shock protein 90 (Hsp90) family are a prerequisite for successful viral propagation for most viruses. The hepatitis C virus (HCV) uses Hsp90 for maturation, folding, and modification of viral proteins. Based on our previous discovery that marine alkaloid analogues with a 4,5,6,7-tetrahydrobenzo[1,2-d]thiazole-2-amine structure show inhibition of HCV replication and binding to Hsp90, a series of twelve novel compounds based on this scaffold was designed and synthesized. The aim was improved Hsp90 affinity and anti-HCV activity. Through structural optimization, improved binding to Hsp90 and specific HCV inhibition in genotype 1b and 2a replicon models was achieved for three compounds belonging to the newly synthesized series. Furthermore, these compounds efficiently inhibited replication of full-length HCV genotype 2a in a reporter virus RNA assay with IC₅₀ values ranging from 0.03 to 0.6 μm .     

Numerical Analysis of the Impact of Particle Friction on Bed Voidage in Fixed‐Beds

The impact of the static friction coefficient, the initial particle orientation, and the particle height‐to‐diameter ratio on the bed voidage of random packings with a low tube‐to‐particle diameter ratio is investigated for spherical and cylindrical particles using the discrete element method. Based on the numerical results a correlation is proposed to predict the bed voidage as a function of the static friction coefficient and the tube‐to‐particle diameter ratio for spheres, equilateral and non‐equilateral cylinders. This correlation is extended for the use of hollow cylinders.