Risikofaktoren und Prävention aggressiven Verhaltens von Kindern und Jugendlichen

Contrary to often very simplified explanatory approaches published in the media, the ongoing research takes into account a multi-causal framework and different developmental processes with respect to the causes of aggressive behavior. Meanwhile, a bio-psycho-social model has been established which broadly describes the conditions correlating with the development of aggressive behavior. In addition to the developmental risk and the protective factors listed in this model, situative factors such as provocation, special incentives, ownership of weapons and other provoking factors are also decisive. In accordance with the broad range of developmental and triggering factors, numerous interventions and most of all preventive programs are suggested to reduce aggressive behavior. One of the most intensively evaluated and internationally known prevention programs is “Faustlos” (“without fists”). This article outlines evaluation outcomes, content and structure of the Faustlos-curriculum. The text also summarizes the risk and protective factors for aggressive behavior in children and adolescents. (DIPF/Orig.)Im Gegensatz zu den teilweise sehr vereinfachenden Erklärungsansätzen in den Medien, ist bezüglich der Ursachen für aggressives Verhalten von einem multikausalen Bedingungsgefüge und unterschiedlichen Entwicklungsverläufen aggressiven Verhaltens auszugehen. Für eine umfassende Beschreibung der Bedingungen, die mit der Entstehung aggressiven Verhaltens korrelieren, hat sich inzwischen ein bio-psycho-soziales Modell etabliert. Neben den hier aufgeführten ursächlichen Risiko- und Schutzfaktoren sind für das Auftreten aggressiver Verhaltensweisen auch situative Faktoren wie Provokationen, spezielle Anreize, Waffenbesitz und andere auslösende Momente entscheidend. Entsprechend der breiten Palette ursächlicher und auslösender Faktoren werden zur Eindämmung aggressiven Verhalten vielfältige Interventions- und v.a. Präventionsmaßnahmen vorgeschlagen. Eines der am intensivsten evaluierten und international sehr verbreiteten Präventionsprogramme ist „Faustlos“. Im vorliegenden Artikel werden Evaluationsergebnisse, Inhalte und Struktur des Faustlos-Programms beschrieben, und es werden die Risiko- und Schutzfaktoren aggressiven Verhaltens von Kindern und Jugendlichen zusammenfassend dargestellt. (DIPF/Orig.

Tachycardia: The hidden cardiovascular risk factor in uncomplicated arterial hypertension

Early detection and management of elevated blood pressure is crucial in reducing the burden of cardiovascular disease (CVD). The importance of an absolute risk assessment and patient risk stratification has been highlighted in the European hypertension guidelines since 2003. Amongst numerous risk factors influencing patient prognosis, elevated heart rate (HR) has been indicated as important predictor of future risk of hypertension, coronary heart disease, sudden cardiac death, heart failure, CVD, stroke, total cancer and mortality. Given that resting HR can be easily determined in clinical practice and modified by lifestyle changes as well as beta-blocker therapy, it seems reasonable that lowering resting HR should be a potential target to reduce disease burden and premature mortality. However, there is a lack of outcome studies of HR lowering in tachycardia-related hypertension. This review outlines the underlying mechanisms of early course hypertension pathophysiology with the critical role of the sympathetic nervous system activation, the prognostic significance of fast HR and the mechanistic rationale for the use of non-pharmacological approaches and/or highly long-acting cardioselective beta-blockers with some consideration given to betaxolol properties

Optical measurements on thermal convection processes inside thermal energy storages during stand-by periods

Thermal energy storages (TES) are increasingly important for storing energy from renewable energy sources. TES that work with liquid storage materials are used in their most efficient way by stratifying the storage fluid by its thermal density gradient. Mixing of the stratification layers during stand-by periods decreases the thermal efficiency of the TES. Tank sidewalls, unlike the often poorly heat-conducting storage fluids, promote a heat flux from the hot to the cold layer and lead to thermal convection. In this experimental study planar particle image velocimetry (PIV) measurements and background-oriented schlieren (BOS) temperature measurements are performed in a model experiment of a TES to characterise the influence of the thermal convection on the stratification and thus the storage efficiency. The PIV results show two vertical, counter-directed wall jets that approach in the thermocline between the stratification layers. The wall jet in the hot part of the thermal stratification shows compared to the wall jet in the cold region strong fluctuations in the vertical velocity, that promote mixing of the two layers. The BOS measurements have proven that the technique is capable of measuring temperature fields in thermally stratified storage tanks. The density gradient field as an intermediate result during the evaluation of the temperature field can be used to indicate convective structures that are in good agreement to the measured velocity fields

A combined velocity and temperature measurement with an LED and a low-speed camera

Microfluidic devices are governed by three-dimensional velocity and temperature fields, and their boundary conditions are often unknown. Therefore, a measurement technique is often desired to measure both fields in a volume. With astigmatism particle tracking velocimetry (APTV) combined with luminescence lifetime imaging, the temperature and all velocity components in a volume can be measured with one optical access. While the three-dimensional particle position is determined by evaluating the shape of the corresponding particle image, the temperature measurement relies on estimating the temperature-dependent luminescence lifetime derived from particle images on two subsequent image captures shortly after the photoexcitation. For this, typically a high-energetic pulsed laser is required to ensure a high signal-to-noise ratio. However, it can also cause additional heating of the fluid. We show that this problem is solved by replacing the pulsed laser with an LED. To compensate for the lower power provided by the LED, we adapted the timing schedule and vastly extended the illumination time and the exposure time for both image captures. In addition, we were able to replace the typically used high-speed camera with an ordinary double-frame camera. In this way, very low measurement uncertainties on all measured quantities can be achieved while keeping the temperature of the fluid unaffected. Random errors dominate within the two focal planes of APTV, yielding a standard deviation of the temperature of individual particles of about 1 only. The measurement error caused by the movement of tracer particles during the much longer illumination and exposure time were found to be acceptable when the measured velocity is low. With the circumvention of light-source induced heating and the lower cost of hardware devices, the adapted approach is a suitable measurement technique for microfluidic related research

Die Rolle Dendritischer Zellen bei der Induktion der Experimentellen Autoimmun-Enzephalomyelitis

In dieser Arbeit werden Mäuse zur aktiven Induktion der Experimentellen autoimmunen Enzephalomyelitis (EAE) mit einem Myelinantigen s.c. immunisiert. Hierfür wird das Myelin Oligodendroglia Glykoprotein (MOG) in Komplettem Freund’schen Adjuvans (Complete Freund’s adjuvans, CFA) mit zusätzlichen Anteilen hitzeinaktivierter Mykobakterien (M. tuberculosis, MT) emulgiert. Zusätzlich wird den Tieren Pertussis Toxin (PT) i.p. injiziert. Nach etwa zehn bis zwölf Tagen entwickeln die Tiere aufsteigende Lähmungserscheinungen. Die Aktivierung autoreaktiver T-Zellen stellt den initialen Schritt zur Auslösung der Autoimmunerkrankung dar. Da in vivo die antigenspezifische Aktivierung naiver T-Zellen ausschließlich über Dendritische Zellen (DZ) vermittelt wird, spielen DZ vermutlich auch bei der EAE-Induktion eine entscheidende Rolle. Zur Charakterisierung der Aktivierungsbedingungen, unter welchen in vitro generierte DZ in der Lage sind, nach Antigenbeladung und Injektion die EAE auszulösen, wurden zunächst DZ aus Knochenmarksvorläuferzellen generiert und mit MT oder PT inkubiert. Dies führte zur Produktion proinflammatorischer Zytokine wie TNF und IL-12, zusätzlich wurde das regulatorische Zytokin IL-10 produziert. Die Beladung dieser DZ mit MOG und die anschließende Immunisierung von Mäusen durch s.c. Injektion resultierte in einer starken TH1-Immunantwort mit deutlicher Proliferation der CD4+ T-Zellen und massiver IFN-g Produktion, jedoch dem Fehlen einer klinischen EAE. Die Untersuchung zeigte, dass eine primäre T-Zellantwort gegen das Myelinantigen induziert wurde, diese jedoch nicht zum Ausbruch von Autoimmunität ausreichte. Beim Vergleich der Immunisierung durch CFA mit der mittels DZ, wurden Unterschiede in der Menge der induzierten Zytokine bei gleicher Proliferation festgestellt. So konnten nach CFA-Immunisierung höhere Mengen des inflammatorischen Zytokins IFN-g und deutlich niedrigere Mengen des regulatorischen Zytokins IL-10 im Vergleich zur DZ-Immunisierung gemessen werden. Die gesteigerte Produktion von IL-10 nach DZ-Immunisierung deutete auf die Induktion regulatorischer T-Zellen hin, die in der Lage sind, die TH1-induzierte EAE komplett zu unterdrücken. Bemühungen, mit der gezielten i.p. Injektion von IFN-g, IL-12, LPS oder CpG, die Produktion von IFN-g zu steigern und IL-10 zu senken, gelangen zwar, führten jedoch nicht zur Induktion der EAE. Mit der Verwendung IL-10-gendefizienter Mäuse und der Depletion regulatorischer T-Zellen durch Verwendung des Antikörpers PC61 und der anschließenden DZ-Immunisierung wurde schließlich eine direkte Abhängigkeit der EAE-induktion von der Abwesenheit oder Inaktivität regulatorischer T-Zellen widerlegt. Die Induktion von Autoimmunität nach DZ-Immunisierung gelang bisher im Hepatitis- und Myokarditismodell (SACHER et al. 2002; ERIKSSON et al. 2003), womit der Blut-Hirn-Schranke (BHS) als natürliche Barriere eine Sonderstellung zukommt. Die vorliegende Arbeit zeigt, dass die DZ-Immunisierung IL-12 transgener Mäuse die Entwicklung der typischen Ataxien nach zehn Tagen induzierte. Folglich werden nach DZ-Immunisierung autoreaktive TH1-Zellen induziert, welche nach Eintritt ins ZNS in der Lage sind Lähmungserscheinungen durch Schädigung der Myelinscheide hervorzurufen. Neuere Forschungsergebnisse, unter anderem von CUA et al. (2003) und Langrish et al. (2005), heben die Bedeutung von IL-23 und IL-17 für den Aktivierungsweg der EAE hervor. Zukünftige Untersuchungen hinsichtlich dieser Zytokine basierend auf dem hier entwickelten DZ-Immunisierungsmodell wären von Interesse

On the application of neural networks for temperature field measurements using thermochromic liquid crystals

This study presents an investigation regarding the applicability of neural networks for temperature measurements using thermochromic liquid crystals (TLCs) and discusses advantages as well as disadvantages of common calibration approaches. For the characterization of the measurement technique, the dependency of the color of the TLCs on the temperature as well as on the observation angle and, therefore, on the position within the field of view of a color camera is analyzed in detail. In order to consider the influence of the position within the field of view on the color, neural networks are applied for the calibration of the temperature measurements. In particular, the focus of this study is on analysis of the error of temperature measurement for different network configurations as well as training methods, yielding a mean absolute deviation and a mean standard deviation in the range of 0.1 K for instantaneous measurements. On the basis of a comparison of this standard deviation to that of two further calibration approaches, it is shown that neural networks are suited for temperature measurements via the color of TLCs. Finally, the applicability of this measurement technique is illustrated at an exemplary temperature measurement in a horizontal plane of a Rayleigh-Bénard cell with large aspect ratio, which clearly shows the emergence of convective flow patterns by means of the temperature field

Stereoscopic PIV measurements using low-cost action cameras

Recently, large progress was made in the development towards low-cost PIV (Particle Image Velocimetry) for industrial and educational applications. This paper presents the use of two low-cost action cameras for stereoscopic planar PIV. A continuous wave laser or alternatively an LED was used for illumination and pulsed by a frequency generator. A slight detuning of the light pulsation and camera frame rate minimizes systematic errors by the rolling shutter effect and allows for the synchronization of both cameras by postprocessing without the need of hardware synchronization. The setup was successfully qualified on a rotating particle pattern in a planar and stereoscopic configuration as well as on the jet of an aquarium pump. Since action cameras are intended to be used at outdoor activities, they are small, very robust and work autarkic. In conjunction with the synchronization and image pre-processing scheme presented herein, those cameras enable stereoscopic PIV in harsh environments and even on moving experiments

Long-time experimental investigation of turbulent superstructures in Rayleigh-Bénard convection by noninvasive simultaneous measurements of temperature and velocity fields

Large-scale mean patterns in Rayleigh-Bénard convection, also referred to as turbulent superstructures, have mainly been studied by means of numerical simulations so far, but experimental investigations are still rare. However, the analysis of turbulent superstructures, which are of great importance due to their effect on the local transport of heat and momentum, require both numerical and experimental data. Therefore, within the scope of this study measurements were performed in the horizontal mid plane and in a horizontal plane closer to the top of a Rayleigh-Bénard cell with an aspect ratio of [Gamma]=l/h=25, thereby showing the initial formation of turbulent superstructures and their long-time rearrangement. The turbulent superstructures are investigated experimentally by noninvasive simultaneous measurements of temperature and velocity fields, using the color signal of thermochromic liquid crystals (TLCs) for the evaluation of the temperature and their temporal displacement for the determination of all three velocity components in the measurement planes via stereoscopic particle image velocimetry (stereo-PIV). Applying this measuring technique it is demonstrated that the time-averaging of instantaneous temperature and velocity fields uncovers the turbulent superstructures in both fields. Furthermore, the combination of the temperature and velocity data is used to characterize the local heat flux quantified by the local Nusselt number, which confirms that the turbulent superstructures strongly enhance the heat transfer in Rayleigh-Bénard convection