AHAPS-functionalized silica nanoparticles do not modulate allergic contact dermatitis in mice

Allergic contact dermatitis (ACD) is a common skin disease in people and may become a potential site of exposure to nanoparticles (NP). Silica nanoparticles (SiO₂-NP) possess a promising potential for various medical and non-medical applications, including normal and diseased skin as target organs. However, it has been shown that negatively charged SiO₂-NP may act as proinflammatory adjuvant in allergic diseases. The effect of topical SiO₂-NP exposure on preexisting ACD has not been studied to date although this reflects a common in vivo situation. Of particular interest are the potential effects of positively charged N-(6-aminohexyl)-aminopropyltrimethoxysilane (AHAPS)-functionalized SiO₂-NP which are promising candidates for delivery systems, including gene delivery into the skin. Here, the effects of such AHAPS-functionalized SiO₂-NP (55 ± 6 nm in diameter) were studied in an oxazolone-induced ACD model in SKH1 mice and compared to ACD mice treated with vehicle only. The clinical course of the disease was assessed by monitoring of the transepidermal water loss (TEWL) and the erythema. In histologic and morphometric analyses, the distribution of particles, the degree of inflammation, epidermal thickness, and the inflammatory infiltrate were characterized and quantified by standard and special histological stains as well as immunohistochemistry for CD3+ lymphocytes. To assess possible systemic effects, serum immunoglobulin E (IgE) was determined by enzyme-linked immunosorbent assay. Following administration of AHAPS-SiO₂-NP for five consecutive days, no effects were observed in all clinical, histologic, morphometric, and molecular parameters investigated. In conclusion, positively charged AHAPS-SiO₂-NP seem not to affect the course of ACD during exposure for 5 days.     

Thermal issues in machine tools

This paper presents a review of the latest research activities and gives an overview of the state of the art in understanding changes in machine tool performance due to changes in thermal conditions (thermal errors of machine tools). The topics are focused on metal cutting machine tools, especially on turning and milling machines as well as machining centres. The topics of the paper thermal issues in machine tools include measurement of temperatures and displacements, especially displacements at the tool centre point, computations of thermal errors of machine tools, and reduction of thermal errors. Computing the thermal errors of machine tools include both, temperature distribution and displacements. Shortly addressed is also to avoid thermal errors with temperature control, the influence of fluids and a short link to energy efficiency of machine tools. The paper presents the summary of research work in the past and current. Research challenges in order to achieve a thermal stable machine tool are discussed. The paper apprehend itself as an update and not a substitution of two published keynote papers of Bryan et al. [28] in 1990 and Weck et al. [199] in 1995.     

Small Pitch Transition-Edge Sensors with Broadband High Spectral Resolution for Solar Physics

We are developing small pitch transition-edge sensor (TES) X-ray detectors optimized for solar astronomy. These devices are fabricated on thick Si substrates with embedded Cu heat-sink layer. We use 35×35?μm² Mo/Au TESs with 4.5?μm thick Au absorbers. We have tested devices with different geometric absorber stem contact areas with the TES and surrounding substrate area. This allows us to investigate the loss of athermal phonons to the substrate. Results show a correlation between the stem contact area and a broadening in the spectral line shape indicative of athermal phonon loss. When the contact area is minimized we have obtained exceptional broadband spectral resolution of 1.28±0.03?eV at an energy of 1.5?keV, 1.58±0.07?eV at 5.9?keV and 1.96±0.08?eV at 8?keV. The linearity in the measured gain scale is understood in the context of the longitudinal proximity effect from the electrical bias leads resulting in transition characteristics that are strongly dependent upon TES size.     

Der Frequenzgang des Wirkungsgrades eisengesehlossener Transformatoren

Ohne ZusammenfassungAuszug aus einer Dissertation der Technischen Hochschule München: Studien an Transformatoren unter besonderer Berücksichtigung ihres Verhaltens bei verschiedenen Frequenzen, 1934.     

Oxygen Processing of Hg and Tl Based Cuprate Superconductors

The effect that oxygen stoichiometry has on the physical properties of high critical temperature superconductors is well documented. For a general understanding of the conditions necessary for processing high critical temperature superconducting materials, phase equilibrium diagrams have been quite useful; however, such diagrams provide no information concerning the time required to oxygenate superconducting structures. In this paper, we present experimental results that clearly demonstrate the relationships among phase equilibrium diagrams, oxygen diffusion coefficients and grain sizes with the time required to adequately oxygenate high critical temperature superconducting materials and device structures. While oxygen processing of the high critical temperature superconductor, YBa₂Cu₃O_7–, is emphasized throughout this paper, the concepts and relationships discussed herein, in general, can be applied to the oxygen processing of other high critical temperature superconductors including the Hg and TI based systems.where the investigations were conducted has been transferred to the U.S. Army Research LaboratoryD.M. Pierce: Work performed while a National Research Council Associate     

Experimental investigation on heat transfer from a heated rod with a helically wrapped wire inside a square vertical channel to water at supercritical pressures

A supercritical water heat transfer test section has been built at Xi’an Jiaotong University to study the heat transfer from a 10 mm rod inside a square vertical channel with a wire-wrapped helically around it as a spacer. The test section is 1.5 m long and the wire pitch 200 mm. Experimental conditions included pressures of 23–25 MPa, mass fluxes of 500–1200 kg/m² s, heat fluxes of 200–800 kW/m², and inlet temperatures of 300–400 °C. Wall temperatures were measured with thermocouples at various positions near the rod surface. The experimental Nusselt numbers were compared with those calculated by empirical correlations for smooth tubes. The Jackson correlation showed better agreement with the test data compared with the Dittus-Boelter correlation but overpredicted the Nusselt numbers almost within the whole range of experimental conditions. Both correlations cannot predict the heat transfer accurately when deterioration occurred at low mass flux and relatively high heat flux in the pseudocritical region. Comparison of experimental data at two different supercritical pressures showed that the heat transfer was more enhanced at the lower supercritical pressure but the deterioration was more likely to occur at the higher pressure, meaning increased safety. Based on a comparison with an identical channel without the helical wrapped wire, it was found that the wire spacer does not enhance the heat transfer significantly under normal heat transfer conditions, but it contributes to the improvement of the heat transfer in the pseudocritical region and to a downstream shift of the onset of the deterioration. The Jackson buoyancy criterion is found to be valid and works well in predicting the onset of heat transfer deterioration occurring in the experiments without wire.     

Pulsed‐Magnetic Hot Joining ‐ New Solutions for Modern Lightweight Structures

To further significantly reduce the car weight, new and innovative production technologies are necessary which allow to join aluminium and – in the future – magnesium profiles. Then it will be possible to connect components made of aluminium or magnesium base alloy with steel parts to one group. Such a new technology is pulsed‐magnetic joining. In order to lower the process forces necessary for pulsed‐magnetic joining of high strength aluminium alloys and in order to establish a technologically useful forming of magnesium alloys, joining at increased temperatures appears to be a viable solution. As part of the research a tool for pulsed‐magnetic hot joining has been developed that combines the processes of heating by induction and pulsed‐magnetic joining. The applicability and the potentials of the tool have been demonstrated with hot joining of aluminium and magnesium profiles. The combination of the techniques allows for the first time to join magnesium profiles with forming by using pulsed‐magnetic forming at high temperatures. Regarding aluminium the combination of the techniques allows a significant reduction of the magnetic pressure that is necessary for the forming process; it thereby increases the operating life of the tools.     

Emotions over time: Synchronicity and development of subjective, physiological, and facial affective reactions to music.

Most people are able to identify basic emotions expressed in music and experience affective reactions to music. But does music generally induce emotion? Does it elicit subjective feelings, physiological arousal, and motor reactions reliably in different individuals? In this interdisciplinary study, measurement of skin conductance, facial muscle activity, and self-monitoring were synchronized with musical stimuli. A group of 38 participants listened to classical, rock, and pop music and reported their feelings in a two-dimensional emotion space during listening. The first entrance of a solo voice or choir and the beginning of new sections were found to elicit interindividual changes in subjective feelings and physiological arousal. Quincy Jones' "Bossa Nova" motivated movement and laughing in more than half of the participants. Bodily reactions such as "goose bumps" and "shivers" could be stimulated by the "Tuba Mirum" from Mozart's Requiem in 7 of 38 participants. In addition, the authors repeated the experiment seven times with one participant to examine intraindividual stability of effects. This exploratory combination of approaches throws a new light on the astonishing complexity of affective music listening. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of friction on the material flow during precision forging of helical gears

At the Institute of Metal forming and Metal forming machine tools (IFUM), University of Hannover, helical gearwheels are produced from cylindrical billets using single state precision forging processes. For a process integrated heat treatment, the workpiece materials need to be carburized already before the forming operation. Thus, in contrast to conventional manufacture, an inhomogeneous case depth distribution is obtained resulting from the material flow during forming. A numerical process simulation with the finite element method (FEM) enables to predict this distribution along the shape of the teeth. The performed experimental and numerical investigations illustrate the influence of friction conditions on the material flow and thus its influence on the case depth distribution.