951 research outputs found
Structure of spaces of germs of holomorphic functions
Let be a Frechet (resp. Frechet-Hilbert) space. It is shown that (resp. ) if and only if [\Cal H(O_E)]'\in(\Omega) (resp. [\Cal H(O_E)]'\in (DN)). Moreover it is also shown that if and only if \Cal H_b(E')\in (DN). In the nuclear case these results were proved by Meise and Vogt \cite{2}
Antibacterial Effect of Eicosapentaenoic Acid against Bacillus cereus and Staphylococcus aureus: Killing Kinetics, Selection for Resistance, and Potential Cellular Target
Polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA; C20:5n-3), are attracting interest as possible new topical antibacterial agents, particularly due to their potency and perceived safety. However, relatively little is known of the underlying mechanism of antibacterial action of EPA or whether bacteria can develop resistance quickly against this or similar compounds. Therefore, the aim of this present study was to determine the mechanism of antibacterial action of EPA and investigate whether bacteria could develop reduced susceptibility to this fatty acid upon repeated exposure. Against two common Gram-positive human pathogens, Bacillus cereus and Staphylococcus aureus, EPA inhibited bacterial growth with a minimum inhibitory concentration of 64 mg/L, while minimum bactericidal concentrations were 64 mg/L and 128 mg/L for B. cereus and S. aureus, respectively. Both species were killed completely in EPA at 128 mg/L within 15 min at 37 °C, while reduced bacterial viability was associated with increased release of 260-nm-absorbing material from the bacterial cells. Taken together, these observations suggest that EPA likely kills B. cereus and S. aureus by disrupting the cell membrane, ultimately leading to cell lysis. Serial passage of the strains in the presence of sub-inhibitory concentrations of EPA did not lead to the emergence or selection of strains with reduced susceptibility to EPA during 13 passages. This present study provides data that may support the development of EPA and other fatty acids as antibacterial agents for cosmetic and pharmaceutical applications
DEVELOPMENT OF COAXIAL ROTOR MICRO UNMANNED AERIAL VEHICLE
Micro Unmanned Helicopter with ability of takeoff, landing and hovering offeres excellent support tool for missions in indoor environment. In this paper, a review of preliminary studies towards the development of autonomous coaxial helicopter MAV is presented. The paper starts with the statement of coaxial helicoper MAV development. Then, it is continued by the introduction of development of dynamic model for a typical coaxial rotor platform. In the third issues, initial steps in development of sensory system and control system will be dealt with. In brief, an analytical mathematical model has successful derived. This model together with the developed sensor system will act important role towards the full development of the dynamics model as the system identification is carried out
Interaction of sulphonylurea derivatives with vascular ATP-sensitive potassium channels in humans
Design and Topology Optimisation of Tissue Scaffolds
Tissue restoration by tissue scaffolding is an emerging technique with many potential applications. While it is well-known that the structural properties of tissue scaffolds play a critical role in cell regrowth, it is usually unclear how optimal tissue regeneration can be achieved. This thesis hereby presents a computational investigation of tissue scaffold design and optimisation. This study proposes an isosurface-based characterisation and optimisation technique for the design of microscopic architecture, and a porosity-based approach for the design of macroscopic structure. The goal of this study is to physically define the optimal tissue scaffold construct, and to establish any link between cell viability and scaffold architecture. Single-objective and multi-objective topology optimisation was conducted at both microscopic and macroscopic scales to determine the ideal scaffold design. A high quality isosurface modelling technique was formulated and automated to define the microstructure in stereolithography format. Periodic structures with maximised permeability, and theoretically maximum diffusivity and bulk modulus were found using a modified level set method. Microstructures with specific effective diffusivity were also created by means of inverse homogenisation. Cell viability simulation was subsequently conducted to show that the optimised microstructures offered a more viable environment than those with random microstructure. The cell proliferation outcome in terms of cell number and survival rate was also improved through the optimisation of the macroscopic porosity profile. Additionally artificial vascular systems were created and optimised to enhance diffusive nutrient transport. The formation of vasculature in the optimisation process suggests that natural vascular systems acquire their fractal shapes through self-optimisation
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Evaluating Feed Delivery Performance in Scaled Double-Shell Tanks - 14070
The Hanford Tank Operations Contractor (TOC) and the Hanford Waste Treatment and Immobilization Plant (WTP) contractor are both engaged in demonstrating mixing, sampling, and transfer system capability using simulated Hanford High-Level Waste (HLW) formulations. This work represents one of the remaining technical issues with the high-level waste treatment mission at Hanford. The TOCs� ability to adequately mix and sample high-level waste feed to meet the WTP WAC Data Quality Objectives must be demonstrated. The tank mixing and feed delivery must support both TOC and WTP operations. The tank mixing method must be able to remove settled solids from the tank and provide consistent feed to the WTP to facilitate waste treatment operations. Two geometrically scaled tanks were used with a broad spectrum of tank waste simulants to demonstrate that mixing using two rotating mixer jet pumps yields consistent slurry compositions as the tank is emptied in a series of sequential batch transfers. Testing showed that the concentration of slow settling solids in each transfer batch was consistent over a wide range of tank operating conditions. Although testing demonstrated that the concentration of fast settling solids decreased by up to 25% as the tank was emptied, batch-to-batch consistency improved as mixer jet nozzle velocity in the scaled tanks increased
Inverse lift: a signature of the elasticity of complex fluids?
To understand the mechanics of a complex fluid such as a foam we propose a
model experiment (a bidimensional flow around an obstacle) for which an
external sollicitation is applied, and a local response is measured,
simultaneously. We observe that an asymmetric obstacle (cambered airfoil
profile) experiences a downards lift, opposite to the lift usually known (in a
different context) in aerodynamics. Correlations of velocity, deformations and
pressure fields yield a clear explanation of this inverse lift, involving the
elasticity of the foam. We argue that such an inverse lift is likely common to
complex fluids with elasticity.Comment: 4 pages, 4 figures, revised version, submitted to PR
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