Lung exposure of titanium dioxide nanoparticles induces innate immune activation and long-lasting lymphocyte response in the Dark Agouti rat

Nanomaterial of titanium dioxide (TiO2) is manufactured in large-scale production plants, resulting in risks for accidental high exposures of humans. Inhalation of metal oxide nanoparticles in high doses may lead to both acute and long-standing adverse effects. By using the Dark Agouti (DA) rat, a strain disposed to develop chronic inflammation following exposure to immunoactivating adjuvants, we investigated local and systemic inflammatory responses after lung exposure of nanosized TiO2 particles up to 90 days after intratracheal instillation. TiO2 induced a transient response of proinflammatory and T-cell-activating cytokines (interleukin [IL]-1α, IL-1β, IL-6, cytokine-induced neutrophil chemoattractant [CINC]-1, granulocyte-macrophage colony-stimulating factor [GM-CSF], and IL-2) in airways 1-2 days after exposure, accompanied byaninfluxofeosinophilsand neutrophils. Neutrophil numbers remained elevated for 30 days, whereas the eosinophils declined to baseline levels at Day 8, simultaneously with an increase of dendritic cells and natural killer (NK) cells. The innate immune activation was followed by a lymphocyte expansion that persisted throughout the 90-day study. Lymphocytes recruited to the lungs were predominantly CD4+ helper T-cells, but we also demonstrated presence of CD8+T-cells, B-cells, and CD25+T-cells. In serum, we detected both an early cytokine expression at Days 1-2 (IL-2, IL-4, IL-6, CINC-1, IL-10, and interferon-gamma [IFN-γ] and a second response at Day 16 of tumor necrosis factor-alpha (TNF-α), indicating systemic late-phase effects in addition to the local response in airways. In summary, these data demonstrate a dynamic response to TiO2 nanoparticles in the lungs of DA rats, beginning with an innate immune activation of eosinophils, neutrophils, dendritic cells, and NK cells, followed by a long-lasting activation of lymphocytes involved in adaptive immunity. The results have implications for the assessment of risks for adverse and persistent immune stimulation following nanoparticle exposures in sensitive populations

Anteckningar i räknemetodik för småskolan och folkskolan

1:a upplaga

Design and modeling of a self-sufficient shape-memory-actuator

In machine tools several time and position varying heat sources causes complex temperature distributions. The resulting problems are varying thermal deformations which cause a loss of accuracy as well as non optimal drive conditions. An option to deal with that issue is to use structure integrated SM-actuators which use the thermal energy accumulated by machining processes to yield an actuator displacement. That creates a structure inherent control loop. There the shape-memory-elements work as sensing element as well as actuation element. The plant is defined by the thermal and mechanical behaviour of the surrounding structure. Because of the closed loop operation mode, the mechanical design has to deal with questions of stability and parameter adjustment in a control sense. In contrast to common control arrangements this issues can only be influenced by designing the actuator and the structure. To investigate this approach a test bench has been designed. The heat is yielded by a clutch and directed through the structure to the shape memory element. The force and displacement of the actuator are therefore driven directly by process heat. This paper presents a broad mechanical design approach of the test bench as well as the design of the SMactuator. To investigate the thermo-mechanical behaviour of the structure-integrated actuator, a model of the test bench has been developed. The model covers the thermal behaviour of the test bench as well as the thermo-mechanical couplings of the shape memory actuator. The model has been validated by comprehensive measurements

Dreidimensionaler Textilstrukturmaterialkörper und Verfahren zur Herstellung desselben

The body has a pile yarn (3) and a helical spring element co-determining a three dimensional structure and made of shape-memory material e.g. thermal shape-memory alloy, shape-memory polymer and magnetic shape-memory alloy. Another pile yarn (4) i.e. monofilament, is provided adjacent to the former pile yarn. Two textile cover layers (1, 2) are connected with each other and are provided at a distance from each other by the pile yarns. A sensor e.g. pressure- and/or temperature sensor, detects a loading condition and/or rigidity of zones of the body. An independent claim is also included for a method for manufacturing a three dimensional textile structure material body

Control design and experimental validation of an adaptive spindle support for enhanced cutting processes

In this paper we present an adaptive spindle support that can be used for additional fine positioning movements during machining operations. This is achieved by an overlaid piezo-based hexapodkinematic structure that is mounted between the machine structure and the motor spindle. Here we present the analysis of the spindle support regarding control aspects. The basis is a finite-element-model that was used to determine a state space model of the component. The model was validated by an experimental modal analysis of the structure. Knowing the modal characteristics allows an analysis of the mechanical couplings between the different axes of the spindle support which accordingly enables the design of a controller considering mechanical couplings. For experimental validation the controller was implemented into a rapid prototyping system. The presented results show that during cutting operations the spindle can be moved with high precision within a wide range of frequencies

Formgedächtnismaterialien für die Anwendung im Kraftfahrzeug

Werkstoffe, die in der Lage sind ihre geometrische Grundform durch Einwirkung bestimmter physikalischer Größen in eine eingeprägte alternative Geometrie zu transformieren, nennt man Formgedächtniswerkstoffe. Dabei kann man im Wesentlichen optisch, thermisch und magnetisch induzierte Formgedächtniseffekte unterscheiden. Die entsprechenden Werkstoffe gehören zur Gruppe der aktiven Materialien und befinden sich zum Teil noch in der Grundlagenforschung. Am Fraunhofer IWU in Dresden werden neue Materialien auf ihre Eignung für mechatronische Applikationen im Bereich der Fahrzeugtechnik untersucht. Metallische Formgedächtnislegierungen auf der Basis von NiTi und NiMnGa haben gegenwärtig einen Entwicklungsstand erreicht, der neue Lösungsansätze mit stark vereinfachten mechanischen Strukturen im Einsatzbereich mechatronischer Steller und Antriebe verspricht. Die Auslösung der Aktorwirkung erfolgt bei NiTi-Material mit thermischen Feldern, z.B. durch erwärmte Luft oder direkte elektrische Bestromung. NiMnGa-Materialien benötigen für den Effektaufbau ein magnetisches Feld, z.B. von Elektro- oder Dauermagneten. Im Allgemeinen ist für die Rückformung des Formgedächtnisaktors eine Rückstellkraft erforderlich. Um diese Aufgabe zu lösen, kann die Einbettung des Aktors in ein elastisches Basismaterial mit ausreichend hohem E-Modul erfolgen. Man erhält damit einen Verbundwerkstoff, der auch tragende Funktion übernehmen kann und dabei durch eine elektrische Ansteuerung bezüglich seiner Materialeigenschaften beeinflusst werden kann. Für die Anpassung des aktorischen Kraft-Weg-Verlaufes, der Geometrieänderung und des Umschaltverhaltens muss der Werkstoff entsprechend konditioniert werden. Damit werden die Leistungsfähigkeit und die Lebensdauer des Aktorelementes bestimmt. Die Materialkonditionierung erfolgt durch ein thermomechanisches Training oder mit entsprechenden Technologien, die bereits im Herstellungsprozess der Halbzeuge zum Tragen kommen

Mechatronic options for increasing productivity and accuracy in production

This paper presents mechatronic options to increase the productivity and accuracy in Production. Additional piezo-based components in drive trains can significantly improve the dynamic behaviour of machine tools. In this article we present a piezo-based actuator-sensor-unit that is able to reduce uniaxial vibrations in ball screw driven feed axis of machine tools. Using this component yielded in an increase of the drives controller parameters by more than 100%. Beyond this piezo-based-components also possess to increase the accuracy during milling operations and even allow additional fine positioning movements during machining operations. In this paper we present an adaptive spindle as an example to benefit both. This is achieved by an overlaid piezo-based hexapod-kinematics that is mounted between the machine structure and the motor spindle. Shape Memory Alloys and Phase Change Materials represent another group of active materials that are usable to increase accuracy and dynamics. Concerning thermal machine behaviour they are suitable to compensate thermal deformations. Compared to piezo-based solutions they rather don't need additional energy because the activation energy is supplied by the process

Self-controlling structures using thermal shape memory alloys

Due to their high specific workloads and small spatial requirements, shape memory alloys (SMA) possess an outstanding potential to serve as miniaturized positioning devices in small machines. They provide sensory and actory capabilities, being self-sufficient and a structure inherent control loop. Based on its unique properties we present examples of SMA-actuated applications and methods of modeling systems, in which the material is used to compensate thermal induced strain in machine tool relevant applications and show how the overall system design can be achieved

Chemical Weapons, Ayatollah Khomeini and Islamic Law

Peer reviewe