Microstructure and mechanical properties of hard Acrocomia mexicana fruit shell.

Fruit and nut shells can exhibit high hardness and toughness. In the peninsula of Yucatan, Mexico, the fruit of the Cocoyol palm tree (Acrocomia mexicana) is well known to be very difficult to break. Its hardness has been documented since the 1500 s, and is even mentioned in the popular Maya legend The Dwarf of Uxmal. However, until now, no scientific studies quantifying the mechanical performance of the Cocoyol endocarp has been found in the literature to prove or disprove that this fruit shell is indeed "very hard". Here we report the mechanical properties, microstructure and hardness of this material. The mechanical measurements showed compressive strength values of up to ~150 and ~250 MPa under quasi-static and high strain rate loading conditions, respectively, and microhardness of up to ~0.36 GPa. Our findings reveal a complex hierarchical structure showing that the Cocoyol shell is a functionally graded material with distinctive layers along the radial directions. These findings demonstrate that structure-property relationships make this material hard and tough. The mechanical results and the microstructure presented herein encourage designing new types of bioinspired superior synthetic materials.

[New dietetic recommendations in diabetes mellitus: the implications in enteral nutrition]. / Nuevas recomendaciones dietéticas en diabetes mellitus: implicaciones en nutrición enteral.

In diabetes mellitus there are qualitative and quantitative alterations in the lipid metabolism, which contribute to ischaemic heart disease. The monounsaturated fatty acids (MUFA) may favorably influence the cardiovascular risk factors, and they could replace the saturated fats, in detriment of polyunsaturated fatty acids (PUFA) and carbohydrates (CHO). A series of studies have been done, always on NIDDM patients, which have given rise to reconsidering the dietary recommendations in diabetes mellitus: There is no change in the contribution of proteins (10-20% of the caloric intake), saturated fats (< 10% of the caloric intake), dietary cholesterol (< 300 mg/day), PUFA (10% of the caloric intake), fibre (20-35 g/day), and sodium (< 2.4 g/day), however, the caloric distribution of MUFA and CHO is not defined, but is left up to the judgement of the physician. Enteral nutrition has a series of special characteristics which influence the blood glucose levels of the diabetic patient, as well as having different objectives. In the few published studies, the influence on plasma lipids of an enteral diet rich in MUFA is similar to that published for the oral diets. With respect to the blood glucose, this was less than with the standard formulae, especially in diabetics treated with insulin. In conclusion, we can for see a change of course in the international recommendations on "the diet of the diabetic", even though these may be very slight for the time being.(ABSTRACT TRUNCATED AT 250 WORDS)

[The glycemic response to a test breakfast of an enteral diet with fiber and a high starch content in diabetics treated with insulin and oral antidiabetics]. / Respuesta glucémica a un desayuno de prueba con una dieta enteral con fibra y alto contenido en almidón en diabéticos tratados con insulina y antidiabéticos orales.

An enteral nutrition preparation appeared recently on the Spanish market specifically for diabetic patients. It is a normocaloric and normoproteic formula of low osmolarity, rich in soluble fibre and slow-absorption carbohydrates such as fructose and starch, following the classic norms of the American Diabetics Association. The glycemic response was examined at 0, 30, 60 and 120 minutes following the ingestion of 250 cc of Precitene Diabet as breakfast for 40 diabetic patients, half treated with oral antidiabetic substances (DMado) and the other half with insulin (DMins). In both groups, the greatest glycemic increase was at 60 minutes. In the DMado patients, the increase at 60 minutes (70 mg/dl) was not significantly different from that considered by Skyler as acceptable. The same occurred at 120 minutes (40 mg/dl). In the DMins patients, the glycemic increase at 60 minutes was 27 +/- 29 mg/dl, more than that considered acceptable by Skyler (p 0.0006). After 120 minutes this difference was also greater than the acceptable level, by 41 +/- 38 mg/dl (p 0.0002). In conclusion, it may be considered that, for DMado patients, glycemic control remains within the postprandial limits considered to be "acceptable" so that no treatment modification is felt necessary in the administration of enteral nutrition with Precitene Diabet. The glycemic response in the DMins patients was higher than "acceptable", calling for rapid insulin supplements to their habitual NPH insulin doses.

[Bilateral nodular hyperplasia of the adrenal glands; diagnostic problems]. / Hiperplasia nodular suprarrenal bilateral; problemas en el diagnóstico.

Bilateral adrenal nodular hyperplasia (BAND) is rarely presented as a cause of Cushing Syndrome. The pathogenicity of the disease is unknown and it does not present either symptoms or specific signs, furthermore, its steroid dynamic is atypical and the morphologic tests are not conclusive. The clinical stories of six BAND-diagnosed patients in our Department have been reviewed with the aim of unifying the criteria of the preoperative diagnosis with regard to treatment, comparing our results with literature's wider series. The results from both studies demonstrate an hypophyseal dependence together with some others showing a adrenal autonomy. Thus, our conclusions perpetuate the pathogenic question about BAND (whether is an adrenal primary disfunction or a secondary effect caused by hypophyseal ACTH hypersecretion?) and we point out the usefulness of radioisotopic gammagraphy and abdominal-TAC, since usually they show the bilaterality of the injury at adrenal level.