The effect of hydration on the biomechanical properties of fibrin and fibrin-agarose (FA) tissue-like hydrogels is reported. Native hydrogels with approximately 99.5% of water content and hydrogels with water content reduced until 90% and 80% by means of plastic compression (nanostructuration) were generated. The biomechanical properties of the hydrogels were investigated by tensile, compressive, and shear tests. Experimental results indicate that nanostructuration enhances the biomechanical properties of the hydrogels. This improvement is due to the partial draining of the water that fills the porous network of fibers that the plastic compression generates, which produces a denser material, as confirmed by scanning electron microscopy. Results also indicate that the characteristic compressive and shear parameters increase with agarose concentration, very likely due to the high water holding capacity of agarose, which reduces the compressibility and gives consistency to the hydrogels. However, results of tensile tests indicate a weakening of the hydrogels as agarose concentration increases, which evidences the anisotropic nature of these biomaterials. Interestingly, we found that by adjusting the water and agarose contents it is possible to tune the biomechanical properties of FA hydrogels for a broad range, within which the properties of many native tissues fall.

Grain yield of barley (Hordeum vulgare L.) is influenced by several yield components and also by the duration of the vegetative and grain‐filling periods. Path‐coefficient analyses, based on an ontogenetic diagram, were conducted to study the relationships among grain yield, yield components, and duration of the vegetative and grain‐filling periods. Nine genotypes (including seven near‐isogenic lines) of spring barley varying in heading dates and several morphological traits were grown during the 1987 and 1988 seasons in two environments in the province of Granada in southern Spain. Grain‐yield variations between environments and from year to year depended mainly on two yield components, the number of spikes per square meter and the number of kernels per spike. The average kernel weight had a negligible effect on grain yield. The number of spikes per square meter had a considerable negative influence on kernels per spike but contributed positively to both the length of the grain‐filling period and the average kernel weight. The duration of the vegetative period had a positive influence on the kernels per spike and a negative influence on the length of the grain‐filling period. A lengthening of the grain‐filling period induced an increase in kernels per spike but did not significantly modify the average kernel weight. The path diagram also indicated that variations in the kernels per spike do not significantly influence kernel weight.

For the first time the influence of the chirality of the gel fibers in protein crystallogenesis has been studied. Enantiomeric hydrogels 1 and 2 were tested with model proteins lysozyme and glucose isomerase and a formamidase extracted from B. cereus. Crystallization behaviour and crystal quality of these proteins in both hydrogels are presented and compared.

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