A model for self-assembling circuits with voltage-controlled growth

The circuit tile assembly model (cTAM) consists of a voltage source and resistive circuit tiles, configured as a voltage divider, that attach to form resistive ladders or grids if the voltage on the boundary is greater than or equal to a threshold. The model produces a family of circuits whose composition and properties change with time. As growth proceeds, the voltage decreases until it no longer exceeds a threshold, which causes growth to cease. This is referred to as self-controlled growth, because the properties of the assembly itself are the primary determinant in controlling the extent of the assembly. The model augments tile assembly models, which are programmable through specific chemical interactions, with an alternative electrical mechanism. The ladder and grid assemblies have bounded size and unique shape that are determined by parameters from the electrical network. Using the harmonicity of the electric potential, the shape of the grid assembly is shown to be symmetric around the main diagonal. Finally, two models of growth, differentiated by whether the voltage is measured before or after attachment, are equivalent. The model and analysis have potential application to self-assembly of nanostructures, as well as to networks whose structure changes over time.     

Effect of Processing on Anti-nutritional Factors of Red Kidney Bean (Phaseolus vulgaris) Grains

The effect of different processing methods (soaking in water or solutions of sodium bicarbonate, citric acid, soaking plus cooking, and germination) on anti-nutritional factors (phytic acid, total polyphenols, tannins, and hydrocyanic acid) of red kidney bean was studied. The anti-nutritional factors were reduced significantly (P < 0.001) with processing techniques. Cyanide contents were most effectively (25%) reduced by cooking after soaking in sodium bicarbonate solution, followed by germination. The most drastic effect was noted on tannin contents. Cooking after soaking in either citric acid or sodium bicarbonate solutions almost eliminated it. However, simple soaking in water did not result in any reduction in tannin contents. Reduction in total polyphenols was 78.7% with cooking after soaking in sodium bicarbonate solution. Phytic acid contents were reduced only with germination treatment (42.6%), while the other treatments did not bring about any large reduction.     

Thermal healing of the sub-surface damage layer in sapphire

The sub-surface damage layer formed by mechanical polishing of sapphire is known to reduce the mechanical strength of the processed sapphire and to degrade the performance of sapphire based components. Thermal annealing is one of the methods to eliminate the sub-surface damage layer. This study focuses on the mechanism of thermal healing by studying its effect on surface topography of a- and c-plane surfaces, on the residual stresses in surface layers and on the thickness of the sub-surface damage layer. An atomically flat surface was developed on thermally annealed c-plane surfaces while a faceted roof-top topography was formed on a-plane surfaces. The annealing resulted in an improved crystallographic perfection close to the sample surface as was indicated by a noticeable decrease in X-ray rocking curve peak width. Etching experiments and surface roughness measurements using white light interferometry with sub-nanometer resolution on specimens annealed to different extents indicate that the sub-surface damage layer of the optically polished sapphire is less than 3 μm thick and it is totally healed after thermal treatment at 1450 °C for 72 h.     

Eu–Co substituted Sr-hexaferrites for recording media and microwave devices

Journal of Materials Science: Materials in Electronics - Among ferrites materials, M-type hexaferrites are very important due to their excellent technological applications. In the present...     

Production of biodegradable rods of polycaprolactone/olanzapine for potential application in treatment of Schizophrenia

Olanzapine (OLZ) is a commonly antipsychotic used to treat schizophrenia, a mental illness, with fewer side effects when compared with other drugs of the same class. It is commercialized mainly as oral tablets and orally disintegrating tablets. However, this drug oral bioavailability is affected by the first pass effect and low solubility in water. This requires high daily doses that can cause more side effects and poor treatment compliance. Also, the frequency of frequency of tablet intake is commonly related to patients' abandonment of schizophrenia treatment. So, the development of implantable biomaterials for OLZ delivery can be an alternative to solve both problems, since this material can, potentially, be used subcutaneously in less frequent administrations, thus the treatment has a greater chance of success. Therefore, the objective of this work was to produce polycaprolactone (PCL) rods incorporated with OLZ by hot-melt extrusion technique. The rods were characterized by different techniques, which showed an amount of 6.78 ± 0.56 mg of OLZ per rod. The in vitro release studies were performed and they showed a controlled release of the drug that followed the Higuchi's model. These results indicated that the PCL/OLZ rods have potential application in the schizophrenia treatment.     

Agro-residues for enhanced production of bio-colorants: a feasible approach for dyeing and surface coating of leather

Clean Technologies and Environmental Policy - There is a growing demand for eco-friendly and non-toxic dyes that can be used to impart color to a wide variety of materials. Synthetic dyes are known...     

Effect of vitamin E (Tri E<Superscript>®</Superscript>) on antioxidant enzymes and DNA damage in rats following eight weeks exercise

Background

Exercise is beneficial to health, but during exercise the body generates reactive oxygen species (ROS) which are known to result in oxidative stress. The present study analysed the effects of vitamin E (Tri E^®) on antioxidant enzymes; superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (Cat) activity and DNA damage in rats undergoing eight weeks exercise.

Methods

Twenty four Sprague-Dawley rats (weighing 320-370 gm) were divided into four groups; a control group of sedentary rats which were given a normal diet, second group of sedentary rats with oral supplementation of 30 mg/kg/d of Tri E^®, third group comprised of exercised rats on a normal diet, and the fourth group of exercised rats with oral supplementation of 30 mg/kg/d of Tri E^®. The exercising rats were trained on a treadmill for 30 minutes per day for 8 weeks. Blood samples were taken before and after 8 weeks of the study to determine SOD, GPx, Cat activities and DNA damage.

Results

SOD activity decreased significantly in all the groups compared to baseline, however both exercised groups showed significant reduction in SOD activity as compared to the sedentary groups. Sedentary control groups showed significantly higher GPx and Cat activity compared to baseline and exercised groups. The supplemented groups, both exercised and non exercised groups, showed significant decrease in Cat activity as compared to their control groups with normal diet. DNA damage was significantly higher in exercising rats as compared to sedentary control. However in exercising groups, the DNA damage in supplemented group is significantly lower as compared to the non-supplemented group.

Conclusions

In conclusion, antioxidant enzymes activity were generally reduced in rats supplemented with Tri E^® probably due to its synergistic anti-oxidative defence, as evidenced by the decrease in DNA damage in Tri E^® supplemented exercise group.

     

Design of dental implants,influence on the osteogenesis and fixation

The fixation and the bone ingrowth at the interface of porous cylindrical implants (total porosity of 37% and average pores diameter of 480 microm) were compared in vivo to rough cylindrical implants (R (a) = 5.3 microm), both of commercially pure titanium, made by powder metallurgy. The implants were inserted into the tibias of 20 rabbits and the animals were sacrificed 4 and 8 weeks after surgery. The percentage of bone-implant contact observed in porous implant was significantly larger than in the rough ones for all of sacrifice periods, respectively, 57% vs. 46% after 4 weeks, and 59% vs. 50% after 8 weeks. The mechanical tests showed a significant increase in the shear strength of the porous implants for the two analyzed periods, 4 and 8 weeks (14 and 20 MPa), when compared with rough ones (4 and 13 MPa). These results suggest that porous implants improve the contact at the implant-bone interface and increase the fixation to the bone, improving the osseointegration. Thus, the porous implant might be an alternative to dental implant in less favorable conditions, and appear to be better fixed to bone, offering promising alternatives.