The effects of diet and carcinogen on the natural killer cell activity of sprague dawley rats.

This study was conducted to determine if dietary fat and/or administration of 7,12 dimethylbenz((alpha))anthracene (DMBA) to Sprague Dawley rats affected the natural killer cell activity of these animals.There was no difference in the level of inhibitory activity of NK cells from rats on a low fat diet compared to rats on the high fat diet, when the R(, 2)T(, 2) tumor cell line was used as the target cell.The proliferative activity of NK cells was generally higher in rats on the high fat diet compared to rats on the low fat diet. NK-induced inhibition of YAC-1 cell proliferation correlated inversely with the proliferative activity of the NK cells. Some of the rats fed high fat diets had NK cells whose proliferative activity was approximately twice that of rats fed low fat diets, and whose corresponding inhibitory activity against YAC-1 tumor cells was one-half that of rats on low fat diets.The inhibitory activity of NK cells was dependent on the quantity of fat in the diet of the rats from which these cells were obtained. Rats which were fed a 20% corn oil diet (high fat) generally had lower levels of inhibitory activity against YAC-1 tumor cells compared to rats fed a diet containing 2% linoleic acid (low fat). While choline deficiency or treatment with DMBA did not alter NK cell activity in either dietary group, the combination of both factors caused a significant reduction in NK cell activity when rats were maintained on a high fat diet.The incorporation of ('3)H-thymidine into YAC-1 tumor cells was inhibited when Percoll separated, rat spleen cell fractions, and unseparated spleen cells were cultured with YAC-1 tumor cells.NK cell activity was not constant during the period of study, but tended to display cyclic responses, particularly in rats in the high fat diet.While the ability of NK cells to inhibit proliferation of YAC-1 tumor cells in vitro was diet dependent, the inability to show diet dependency on the ability of NK cells to inhibit the proliferation of R(, 2)T(, 2) tumor cells in vitro did not necesssarily rule out an in vivo role for NK cells in the resistance of rats to DMBA-induced tumors

Surface Modifications in Adhesion and Wetting

Advances in surface modification are changing the world. Changing surface properties of bulk materials with nanometer scale coatings enables inventions ranging from the familiar non-stick frying pan to advanced composite aircraft. Nanometer or monolayer coatings used to modify a surface affect the macro-scale properties of a system; for example, composite adhesive joints between the fuselage and internal frame of Boeing\u27s 787 Dreamliner play a vital role in the structural stability of the aircraft. This dissertation focuses on a collection of surface modification techniques that are used in the areas of adhesion and wetting. Adhesive joints are rapidly replacing the familiar bolt and rivet assemblies used by the aerospace and automotive industries. This transition is fueled by the incorporation of composite materials into aircraft and high performance road vehicles. Adhesive joints have several advantages over the traditional rivet, including, significant weight reduction and efficient stress transfer between bonded materials. As fuel costs continue to rise, the weight reduction is accelerating this transition. Traditional surface pretreatments designed to improve the adhesion of polymeric materials to metallic surfaces are extremely toxic. Replacement adhesive technologies must be compatible with the environment without sacrificing adhesive performance. Silane-coupling agents have emerged as ideal surface modifications for improving composite joint strength. As these coatings are generally applied as very thin layers (\u3c50 nm), it is challenging to characterize their material properties for correlation to adhesive performance. We circumvent this problem by estimating the elastic modulus of the silane-based coatings using the buckling instability formed between two materials of a large elastic mismatch. The elastic modulus is found to effectively predict the joint strength of an epoxy/aluminum joint that has been reinforced with silane coupling agents. This buckling technique is extended to investigate the effects of chemical composition on the elastic modulus. Finally, the effect of macro-scale roughness on silane-reinforced joints is investigated within the framework of the unresolved problem of how to best characterize rough surfaces. Initially, the fractal dimension is used to characterize grit-blasted and sanded surfaces. It is found that, contrary to what has been suggested in the literature, the fractal dimension is independent of the roughening mechanism. Instead, the use of an anomalous diffusion coefficient is proposed as a more effective way to characterize a rough surface. Surface modification by preparation of surface energy gradients is then investigated. Materials with gradients in surface energy are useful in the areas of microfluidics, heat transfer and protein adsorption, to name a few. Gradients are prepared by vapor deposition of a reactive silane from a filter paper source. The technique gives control over the size and shape of the gradient. This surface modification is then used to induce droplet motion through repeated stretching and compression of a water drop between two gradient surfaces. This inchworm type motion is studied in detail and offers an alternative method to surface vibration for moving drops in microfluidic devices. The final surface modification considered is the application of a thin layer of rubber to a rigid surface. While this technique has many practical uses, such as easy release coatings in marine environments, it is applied herein to enable spontaneous healing between a rubber surface and a glass cover slip. Study of the diffusion controlled healing of a blister can be made by trapping an air filled blister between a glass cover slip and a rubber film. Through this study we find evidence for an interfacial diffusion process. This mechanism of diffusion is likely to be important in many biological systems

How a Blister Heals

We use experiments to study the dynamics of the healing of a blister, a localized bump in a thin elastic layer that is adhered to a soft substrate everywhere except at the bump. We create a blister by gently placing a glass cover slip on a PDMS substrate. The pressure jump across the elastic layer drives fluid flow through micro-channels that form at the interface between the layer and the substrate; these channels coalesce at discrete locations as the blister heals and eventually disappear at a lower critical radius. The spacing of the channel follows a simple scaling law that can be theoretically justified, and the kinetics of healing is rate limited by fluid flow, but with a non-trivial dependence on the substrate thickness that likely arises due to channelization. Our study is relevant to a variety of soft adhesion scenarios

Regional Collective Action Wraps Up

After four years, the Regional Collective Action Programme has come to an end. In this final issue of Collective Action News, we report on how Regional Collective Action activities have supported the work of the Consortium and the CRPs. The Regional Collective Action Programme has been described by Carlos Seré, Director General of the International Livestock Research Institute (ILRI), which has hosted the Programme since its inception in 2007, as ‘a bold experiment that achieved considerable success in promoting collaborative action in eastern and southern Africa that has now been overtaken by the process of CGIAR reform’. Many of the activities started under the Programme have now been incorporated into the CGIAR Consortium and the CGIAR Research Programmes (CRPs)

Strategies for Writing a Self-Study and Conducting a Site Review

This presentation will include a discussion of the principle components of a department self-study and provide examples from two departments (English and Fine and Performing Arts). The specific self-study structure we developed is especially beneficial for small university campuses that may need to justify programs or budgetary expenditures

Spatial analyses for policy evaluation of the rural world: Portuguese agriculture in the last decade

This paper aims to contribute to the understanding of structural land use changes that are occurring in rural environments, by using novel methodologies related to Geographic Information Systems (GIS). The land use change analysis developed in this study is associated with a pre-selected set of policy issues, that is, it offers a retrospective view of the application of the Common Agricultural Policy (CAP) for the Portuguese situation. The evaluation of the respective impacts from a spatial perspective raises questions such as: 1) What are the trade-offs of rural activity in different sectors and regions? 2) How do such trade-offs cope with urban proximity?, and 3) Which activities or strategies are best able to balance the needs of rural and urban communities. Methodologically, our work identifies the land use change for the period 1990 – 2000 by comparing the databases CORINE Land Cover 90 and CORINE Land Cover 2000. Further, in order to detect those sectors that, at national or regional level, have taken more advantage of the CAP support, we present a new model, which also takes into account as a major assumption the proximity of rural areas to the nearest towns. The scope of this paper is twofold: addressing a specific problem concerning the effectiveness of the CAP, it develops an extensive empirical and methodological framework able to serve as a model-policy lesson for the rural/agricultural European future

Testing potential new sites for optical telescopes in Australia

In coming years, Australia may find the need to build new optical telescopes to continue local programmes, contribute to global survey projects, and form a local multi-wavelength connection for the new radio telescopes being built. In this study, we refine possible locations for a new optical telescope by studying remotely sensed meteorological infrared data to ascertain expected cloud coverage rates across Australia, and combine these data with a digital elevation model using a geographic information system. We find that the best sites within Australia for building optical telescopes are likely to be on the highest mountains in the Hamersley Range in northwest Western Australia, while the MacDonnell Ranges in the Northern Territory may also be appropriate. We believe that similar seeing values to Siding Spring should be obtainable and with significantly more observing time at the identified sites. We expect to find twice as many clear nights as at current telescope sites. These sites are thus prime locations for future on-site testing