http://www.sciencedirect.com/science/journal/09284931 | An ideal tissue engineering scaffold must be designed from a polymer with an adequate degradation rate. The processing technique must allow for the preparation of 3-D scaffolds with controlled porosity and adequate pore sizes, as well as tissue matching mechanical properties and an appropriate biological response. This communication revises recent work that has been developed in our laboratories with the aim of producing 3-D polymeric structures (from starch-based blends) with adequate properties to be used as scaffolds for bone tissue engineering applications. Several processing methodologies were originally developed and optimised. Some of these methodologies were based on conventional melt-based processing routes, such as extrusion using blowing agents (BA) and compression moulding (combined with particulate leaching). Other developed technologies included solvent casting and particle leaching and an innovative in situ polymerization method. By means of using the described methodologies, it is possible to tailor the properties of the different scaffolds, namely their degradation, morphology and mechanical properties, for several applications in tissue engineering. Furthermore, the processing methodologies (including the blowing agents used in the melt-based technologies) described above do not affect the biocompatible behaviour of starch-based polymers. Therefore, scaffolds obtained from these materials by means of using one of the described methodologies may constitute an important alternative to the materials currently used in tissue engineering.

.K.D Shepherd, 'Development of reflectance spectral libraries for characterization of soil properties', Soil Science Society of America Journal, vol. 66(3), pp.988-998, 2002 | Methods for rapid estimation of soil performance are needed for quantitative assessments of land management problems. We developed a scheme for the use of soil spectral libraries for rapid non-destructive estimation of soil properties based on the use of diffuse reflectance (0.35â??2.5 μm) spectroscopy (DRS). A diverse library of over 1000 archived topsoils from eastern and southern Africa was used to test the approach. Air-dried soil fines were scanned using a portable spectrometer with an artificial light source. Soil properties were calibrated to soil reflectance using multivariate adaptive regression splines, and screening tests were developed for various soil fertility constraints using classification trees. A random sample of one-third of the soils was withheld for validation purposes. Validation r2 values were: exchangeable Ca, 0.88; effective cation-exchange capacity, 0.88; exchangeable Mg, 0.81; organic carbon concentration, 0.80; clay content, 0.80; sand content, 0.76; and soil pH, 0.70. Diagnostic tests for various soil fertility constraints gave positive likelihood ratios for the validation data ranging from 2.7 to 11.4. Calibrations based on a limited number of samples selected from the spectral library provided sufficient predictive accuracy for large-area applications and farm advisory services. We demonstrate how the predictive value of spectral libraries can be iteratively increased through detection of spectral outliers among new samples. The spectral library approach opens up new possibilities for modelling, assessment and management of risk in soil assessments in agricultural, environmental and engineering applications, and provides a coherent framework for linking soil information with multi- and hyperspectral remote-sensing imagery

Three consecutive years of field experiments were carried out to investigate the effect of different root temperatures, induced by the application of mulches on the concentration of sulfur (S) forms (organic-S, total-S and SO24) and Se in different organs of potato plants (roots, tubers, stems and leaves). Four different plastic covers were used (T1: transparent polyethylene; T2: white polyethylene; T3: white and black coextruded polyethylene, and T4: black polyethylene), using uncovered soil as control (T0). The different treatments had a significant effect on mean root temperatures (T0=16ºC, T1=20ºC, T2=23ºC, T3=27ºC and T4=30ºC) and induced a significantly different response in the S forms and Se concentration, showing the T3 treatment (27oC) the greatest concentration of total S and organic S in the stems and leaflets. The Se reached higher levels in the roots and tubers in T3. With regard to possibilities in phytoremediation, it is necessary to control the thermal regime of the soil to optimize the accumulation of elements.

Heat and mass transfer in thin slices of fresh cassava (Manihot esculenta Crantz) were studied. The frying process was described as two stages involving inner vaporization of mainly high available water, which can be transported inside the material, at temperature around the boiling point and inner vaporization of "bound" water at higher temperature depending on water desorption equilibrium. During the first stage, drying rate was controlled by the serial association of both diffusive and convective thermal resistances. During the second stage, temperature gradients decreased and the core temperature followed the corresponding boiling curve (water desorption curve against boiling temperature). Oil uptake depended on the thermal history of the product, characterized by its final water content. Apparent elasticity modulus and color changes were similar for a same final water content. Boiling curves and core temperature measurement are therefore proposed as a means of predicting the development of chip quality during frying.

Polycystic ovary syndrome, which is a complex syndrome, affects approximately 6% of reproductive-age women. Many abnormalities are associated with polycystic ovary syndrome, but confusion still exists about their causation. Diagnosis of polycystic ovary syndrome is by exclusion. Management of the metabolic aspects of polycystic ovary syndrome focuses on minimizing insulin resistance and hyperinsulinemia with diet therapy or insulin-lowering drugs.