Cellulose fibres, nanofibrils and microfibrils: The morphological sequence of MFC components from a plant physiology and fibre technology point of view

During the last decade, major efforts have been made to develop adequate and commercially viable processes for disintegrating cellulose fibres into their structural components. Homogenisation of cellulose fibres has been one of the principal applied procedures. Homogenisation has produced materials which may be inhomogeneous, containing fibres, fibres fragments, fibrillar fines and nanofibrils. The material has been denominated microfibrillated cellulose (MFC). In addition, terms relating to the nano-scale have been given to the MFC material. Several modern and high-tech nano-applications have been envisaged for MFC. However, is MFC a nano-structure? It is concluded that MFC materials may be composed of (1) nanofibrils, (2) fibrillar fines, (3) fibre fragments and (4) fibres. This implies that MFC is not necessarily synonymous with nanofibrils, microfibrils or any other cellulose nano-structure. However, properly produced MFC materials contain nano-structures as a main component, i.e. nanofibrils

Anthropometric indicators and response to gonadotrophin for ovulation induction

A total of 111 women with no ultrasonographic findings of polycystic ovarian syndrome were observed between January 1989 and December 1991 in an in-vitro fertilization (IVF) programme. The treatment schedule involved ovulation induction after treatment with a gonadotrophin-releasing hormone (GnRH) agonist, using standard doses of human menopausal gonadotrophin (HMG) for 4 days, and further stepwise increments in dosage as required. Response to the treatment was defined as: (i) presence/absence of one or more follicles > or = 10 mm diameter after 4 days of treatment, and (ii) oocyte retrieval. Three indices of body mass were considered: weight (W) in kg/height (H)2 in metres (Quetelet's index), W/H1.5 (the National Health and Nutrition Examination Survey anthropometric index for women), W0.30/H (ponderal index). Surface area was computed as 0.0235 (H in cm0.422) (W in kg0.515). Women in the upper tertiles of the range of anthropometric indicators more frequently tended to present no follicle > or = 10 mm on day 7. Likewise, oocytes were retrieved less frequently in subjects in the higher tertile than in those in the lower. The odds ratio of a negative response both on day 7 and at the end of treatment increased with the tertiles of body mass indices or surface areas. This study suggests that response to ovulation induction treatment is inversely related to body mass index