Memory-enhancing effects of secreted forms of the beta-amyloid precursor protein in normal and amnestic mice

When administered intracerebroventricularly to mice performing various learning tasks involving either short-term or long-term memory, secreted forms of the beta-amyloid precursor protein (APPs751 and APPs695) have potent memory-enhancing effects and block learning deficits induced by scopolamine. The memory-enhancing effects of APPs were observed over a wide range of extremely low doses (0.05-5,000 pg intracerebroventricularly), blocked by anti-APPs antisera, and observed when APPs was administered either after the first training session in a visual discrimination or a lever-press learning task or before the acquisition trial in an object recognition task. APPs had no effect on motor performance or exploratory activity. APPs695 and APPs751 were equally effective in the object recognition task, suggesting that the memory-enhancing effect of APPs does not require the Kunitz protease inhibitor domain. These data suggest an important role for APPss on memory processes.     

Vom Damaststahl zum Scharsachstahl

Verbesserung der Schwertklingen durch Damaszierung. Nachweis des Übergangs auf eine andere Schmiedetechnik in der Ritterzeit (11. bis 14. Jh.) an Hand von zwölf mittelalterlichen Schwertern, die aus in der Steiermark hergestellten Stählen nach der Gärbtechnik gefertigt wurden. Kennzeichnung des sogenannten Scharsachstahles mit rd. 0,80% C und seine Verarbeitung zu Schwertklingen mit hoher Elastizität.     

Formation and properties of metallic organotin films

Semiconductive and conductive films of metallic appearance are formed by glow discharge of appropriate organometallic compounds. Tetramethyltin is used as a starting compound for the film-forming experiments. The resulting films contain carbon, tin and hydrogen with a carbon-to-tin atomic ratio of 2.5 or less. These films are semiconductors with conductivities between 2 × 10^-1 and $\text{1 × 10}{}^{-2}\text{Ω}{}^{-1}\text{cm}{}^{-1}$. Transmission electron microscopy shows the films to be amorphous. Films of a certain composition are transformed to β-Sn on exposure to an electron beam. Thermal treatment increases the conductivity gradually to values of about $\text{1 × 10}{}^2\text{Ω}{}^{-1}\text{cm}{}^{-1}$.     

The development of peat-oil (POM) and peat-alcohol (PAM) slurries as alternative fuels

The preparation and evaluation of peat/No. 2 fuel oil mixtures (POM) and peat/methanol mixtures (PAM) is described. POM and PAM prepared using North Carolina peat and having varied peat loadings, peat moisture contents, and peat particle sizes have been studied by measuring slurry sedimentation ratios and drain times from sedimentation tubes. The peat moisture content was particularly crucial in forming stable slurries. The effect of a variety of additives at 0.5–1.0 wt.% on sedimentation ratios, drain times, and viscosities was studied. Calorimetric studies of several PAM and POM slurries as well as preliminary combustion tests of POM slurries in a salamander burner are also reported.     

Electron-beam treatment of aromatic hydrocarbons that can be air-stripped from contaminated groundwater. 2. Gas-phase studies

The electron-beam (EB) degradation of volatile aromatics (benzene, toluene, ethylbenzene, xylenes: BTEX) in groundwater strip gas, which in the present work has been modeled by the introduction of the desired aromatic(s) to a stream of air or another gas, such as oxygen, is initiated essentially by the addition of *OH radicals to the aromatic ring, giving rise to hydroxycyclohexadienyl radicals, which form the corresponding peroxyl radicals upon addition of oxygen. As studied in some detail with benzene as a BTEX representative, various reactions of these lead to numerous oxidation products in a cascade of reactions, including the decomposition of products under the prevailing conditions of high turnover of the initial aromatic. Importantly, hydroxycyclohexadienylperoxyl radical formation is partly reversible, and the reactions of the hydroxycyclohexadienyl radicals, which thus have a significant presence in these systems, must therefore also be taken into consideration. In the gas phase, in contrast to the aqueous phase (see Part 1), the reactions of the hydroxycyclohexadienyl radicals lead to oligomeric products that appear to contribute, in addition to ionic clusters, to nucleation for the aerosols observed. Various nitrated products, among them nitrophenols, are observed when air is used for the stripping. However, these studies did not clear the pilot plant stage, since BTEX degradation using a bioreactor carried out in parallel was so successful that the EB technology was judged to be noncompetitive. As for the latter, expensive equipment consisting of a stripper, the EB machine, and an aerosol precipitator would be required. The condensed aerosols are biorefractory and would require further treatment for detoxification.     

Development of matrix patches for transdermal delivery of a highly lipophilic antiestrogen

The aim of this study was to develop matrix-type transdermal systems (TDSs) containing the highly lipophilic (log P = 5.82) antiestrogen (AE) and the permeation enhancers propylene glycol and lauric acid. For that purpose, permeation of AE from various adhesive matrices through excised skin of hairless mice was evaluated. It was found that pretreatment of the skin with permeation enhancers raised the transdermal flux of subsequently applied antiestrogen. Highest steady-state transdermal fluxes (1.1 µg cm^-2 h^-1) were obtained from Gelva®, polyacrylate adhesive, followed by 0.55 µg cm^-2 h^-1 from Oppanol® polyisobutylene, 0.31 µg cm^-2 h^-1 from BIO-PSA® silicone, and 0.12 µg cm^-2 h^-1 from Sekisui polyacrylate matrices. In order to develop TDS with high content of fluid permeation enhancer propylene glycol, two different strategies were investigated. One strategy was the addition of hydroxypropyl cellulose (HPC) as thickening agent to Gelva matrices. This allowed for propylene glycol loading levels of up to 30%, resulting in transdermal AE fluxes of 0.09 µg cm^-2 h^-1. On the other hand, a fleece-laminated backing foil was loaded with the described permeation enhancer formulation and laminated with polyacrylate adhesive layer, resulting in transdermal AE fluxes of 0.06 µg cm^-2 h^-1. However, application of these TDSs on skin pretreated with permeation enhancers raised the fluxes to 2.6 µg cm^-2 h^-1 from Gelva/HPC and 0.46 µg cm^-2 h^-1 from fleece/Sekisui.     

An effective quantum potential for particle–particle interactions in three-dimensional semiconductor device simulations

The classical Coulomb potential and force can be calculated efficiently using fast multi-pole methods. Effective quantum potentials, however, describe the physics of electron transport in semiconductors more precisely. Such an effective quantum potential was derived previously for the interaction of an electron with a barrier for use in particle-based Monte Carlo semiconductor device simulators. The method is based on a perturbation theory around thermodynamic equilibrium and leads to an effective potential scheme in which the size of the electron depends upon its energy and which is parameter-free. Here we extend the method to electron-electron interactions and show how the effective quantum potential can be evaluated efficiently in the context of many-body problems. Finally several examples illustrate how the momentum of the electrons changes the classical potential.     

Excessive cross-linking of caseins by microbial transglutaminase and its impact on physical properties of acidified milk gels

By varying cross-linking intensity, the effect of microbial transglutaminase on acid gels made from casein solution and raw milk was studied. To avoid any impact of heating, N-ethylmaleimide was used for enzyme inactivation after appropriately checking its efficiency. Up to a specific degree of oligomerisation gel stiffness and firmness increased and tan δ, time at gelation onset and syneresis decreased. Above approximately 70% and 25% of cross-linked protein in casein solution and raw milk, respectively, these parameters showed an opposite behaviour, and weak gels with high syneresis were obtained. Substrate differences, such as preferred cross-linking of adjoining κ-caseins on the surface of the micelle enhanced the effect of steric hindrance in raw milk and impaired proper rearrangements upon acidification at a much lower level of oligomerised protein. It is mainly dimeric and trimeric casein that successfully contributed to the enhanced properties of milk protein gels.