The Chemical Biology of Phosphoinositide 3‐Kinases

Since its discovery in the late 1980s, phosphoinositide 3‐kinase (PI3K), and its isoforms have arguably reached the forefront of signal transduction research. Regulation of this lipid kinase, its functions, its effectors, in short its entire signaling network, has been extensively studied. PI3K inhibitors are frequently used in biochemistry and cell biology. In addition, many pharmaceutical companies have launched drug‐discovery programs to identify modulators of PI3Ks. Despite these efforts and a fairly good knowledge of the PI3K signaling network, we still have only a rudimentary picture of the signaling dynamics of PI3K and its lipid products in space and time. It is therefore essential to create and use novel biological and chemical tools to manipulate the phosphoinositide signaling network with spatial and temporal resolution. In this review, we discuss the current and potential future tools that are available and necessary to unravel the various functions of PI3K and its isoforms.     

Aero-mechanical optimisation of a structural fan outlet guide vane

The aero-mechanical optimisation of a fan outlet guide vane (OGV) in the bypass duct of a modern turbofan engine is presented. The purpose of the described outlet guide vane arrangement is to remove the swirl from the flow coming from the fan and to connect the engine core structurally with the bypass duct and the engine mounts respectively. For that reason the outlet guide vanes have to fulfill aerodynamic requirements—such as low pressure loss and large working range and turning of the absolute flow to 0 degree—as well as the structural requirement to withstand the engine loads in all operating conditions. Such an arrangement has the advantage, that additional struts downstream of the fan outlet guide vane become obsolete, which is beneficial for the engine length and weight and hence the engine specific fuel consumption. At the same time the structural and aerodynamic requirements on such an outlet guide vane are intuitively contradictory. Therefore the design is more complex than for a conventional purely aerodynamic guide vane. To achieve the different requirements the conventional iterative design process has been replaced by a multi-disciplinary approach, which delivers an aero-mechanically optimised fan outlet guide vane geometry based on aerodynamic and mechanical boundary conditions and constraints. The prescribed boundary conditions are the structural load cases (flight conditions) and the aerodynamic inlet and outlet conditions for the fan design point. In addition an existing bypass duct geometry is used to get a valid comparison with a conventionally designed outlet guide vane/strut arrangement. In the structural optimisation, carried out as a parameter study, the effect of several geometrical parameters is investigated using the software ABAQUS. The aerodynamic optimisation is performed using the 2D-CFD-solver MISES on individual profile sections such that a minimum pressure loss and a maximum working range is achieved. For that purpose the profile shape is modified freely taking into account the constraints from the structural optimisation. A 3D-RANS-CFD analysis of the optimised vane and the comparison with the conventional vane/strut arrangement confirmed the improved performance of the chosen design approach and showed a significant reduction in pressure loss (ΔP/D) of nearly 20% compared to the conventional OGV/strut arrangement, leading to an SFC reduction of about 0.5%.     

Modelling and Characterisation of the Texture Development in the Fusion Zone of An Austenitic Weld

The relation between texture and microstructure and the macroscopic solidification direction has been investigated for an austenitic 316L stainless steel weld. The fusion zone has been characterised by EBSD. Texture development has been simulated by thermal Finite Element Analysis coupled with a simple model of preferential <100>‐oriented solidification following the solidification direction. The thermal part is validated by means of thermocouple measurements at several locations on the specimen. The predicted texture is in very good agreement with the measured one.     

Experimental fire analysis of steel‐to‐timber connections using dowels and nails

The paper describes and discusses the results of an extensive testing programme on the structural behaviour of timber connections under ISO‐fire. The results of reference tests performed at normal temperature are also presented. From the variety of timber connections multiple shear steel‐to‐timber connections with dowels and slotted‐in steel plates and connections with steel side plates and annular ringed shank nails were experimentally studied. Particular attention was given to the analysis of the efficiency of different strategies in order to increase the fire resistance of the timber connections. The test results showed that unprotected multiple shear steel‐to‐timber connections with dowels designed for normal temperature reached a fire resistance of about 30 min. A reduction of the load level applied during the fire did not lead to a significant increase of the fire resistance. By increasing the side timber members as well as the end distance of the dowels by 40 mm the connections reached a fire resistance of more than 70 min. Connections protected by timber boards or gypsum plasterboards showed a fire resistance of around 60 min. Thus, from a fire design point of view these strategies were favourable in order to increase the fire resistance of the connections significantly. Unprotected connections with steel side plates and annular ringed shank nails failed already after about 12 min due to large deformations of the nails and the steel side plates directly exposed to fire. By protecting the steel side plates using an intumescent paint the fire resistance of the connections was increased to around 30 min. The test results enlarged the experimental background of timber connections in fire significantly. Copyright © 2009 John Wiley & Sons, Ltd.     

Herausforderungen im modernen Tagebaubetrieb

The article gives ideas for the further development of planning and operation in surface mining. The key role play integrated approaches, like integrated mine planning considering the cutting resistances, integrated planning and operation, integration of exploration, extraction and processing, and integrated consideration of environmental impacts, e.g. geohydrochemical aspects in dumping. The integration approach to consolidate separate processes can contribute to discover new potentials to guarantee safety, environmental acceptability, public acceptance and economy of the system as a whole. Important bricks in these developments are efficient navigation systems, which are today widely accessible, like GPS, sensors to identify process controlling parameters, e.g. rock characteristics for selective mining and dumping, and powerful information technologies for data storage and processing. Additional topics are new developments in mining machines, mining technologies and automation, which are mentioned only in general, on the example of new cutting tool design.     

Linearity of a Silicon Photodiode at 30 MHz and Its Effect on Heterodyne Measurements

The effect of optical irradiance on the linearity of a Si photodiode was studied. These results are compared for light modulated at 30 MHz and at dc as the optical irradiance was varied over a 9 decade range. We discuss how these results affect the use of this detector as a heterodyne receiver. As the optical irradiance varied from 10⁻² to 10⁺³ mW/cm², while maintaining constant total power, the photocurrent was constant to about 1%, but as the power density increased further, the photocurrent increased about 13%. At the highest densities that we could achieve, about 6×10⁷ mW/cm² there was only slight evidence of the onset of saturation. These results are of importance in our work to use optical heterodyne detection to measure filter transmittances over a wide dynamic range. The results provide guidelines for achieving maximum accuracy when using this particular diode as an optical heterodyne receiver.     

The Striped Mouse (Rhabdomys pumilio) From the Succulent Karoo, South Africa: A Territorial Group-Living Solitary Forager With Communal Breeding and Helpers at the Nest.

The authors studied the striped mouse (Rhabdomys pumilio) in the semiarid succulent karoo of South Africa. Mice forage alone, but they live in groups that share a common nest. Groups consist of 1 to 4 breeding females, 1 to 2 breeding males, and their offspring of both sexes, which remain in their natal group even after reaching adulthood, participating in territorial defense and nest building without showing signs of reproductive activity. Interactions are typically amicable and take place inside or in front of the nest. In contrast, encounters with mice from other groups are aggressive. Group living in the succulent karoo is possibly due to ecological constraints imposed by habitat saturation because of a year-round stable food supply as well as associated benefits of philopatry. (PsycINFO Database Record (c) 2010 APA, all rights reserved)