17 research outputs found
Method of separating a particle mixture using a biphasic system
Abstract of GB 2363999 (A) A method of separating a particle mixture comprising first and second types of particle which differ chemically from each other, using a biphasic fluid system comprising a relatively dense first fluid and a relatively less dense second fluid, said fluids being substantially insoluble in each other. The particles PM to be separated and the two fluids are introduced into a separation chamber 10; the content of said chamber is allowed to settle to form an interface between said fluids; particles at the bulk interface are separated from particles near the bottom of the separation chamber - part of the settled material is discharged from 10 as a first stream H1 (denser fluid enriched with second-type of particles) into separation chamber 20, part of inter-phase material discharged as second stream L1 (less dense fluid enriched with first-type of particles) into separation chamber 30. The method is characterised in that:at least the first fluid is a liquid; each particle can be found at the interface between said fluids in the absence of said other particle; the amount of particle mixture introduced into the separation chamber is chosen such that the ratio between the surface area of an interface formed when only the two fluids are present in the separation chamber while at rest and the smallest area occupied by the particles while in contact with a flat surface is & 1.Applied Science
Ovarian Stimulation for In Vitro Fertilization and Long-term Risk of Breast Cancer
Item does not contain fulltextIMPORTANCE: Previous studies of breast cancer risk after in vitro fertilization (IVF) treatment were inconclusive due to limited follow-up. OBJECTIVE: To assess long-term risk of breast cancer after ovarian stimulation for IVF. DESIGN, SETTING, AND PARTICIPANTS: Historical cohort (OMEGA study) with complete follow-up through December 2013 for 96% of the cohort. The cohort included 19,158 women who started IVF treatment between 1983 and 1995 (IVF group) and 5950 women starting other fertility treatments between 1980 and 1995 (non-IVF group) from all 12 IVF clinics in the Netherlands. The median age at end of follow-up was 53.8 years for the IVF group and 55.3 years for the non-IVF group. EXPOSURES: Information on ovarian stimulation for IVF, other fertility treatments, and potential confounders was collected from medical records and through mailed questionnaires. MAIN OUTCOMES AND MEASURES: Incidence of invasive and in situ breast cancers in women who underwent fertility treatments was obtained through linkage with the Netherlands Cancer Registry (1989-2013). Breast cancer risk in the IVF group was compared with risks in the general population (standardized incidence ratios [SIRs]) and the non-IVF group (hazard ratios [HRs]). RESULTS: Among 25,108 women (mean age at baseline, 32.8 years; mean number of IVF cycles, 3.6), 839 cases of invasive breast cancer and 109 cases of in situ breast cancer occurred after a median follow-up of 21.1 years. Breast cancer risk in IVF-treated women was not significantly different from that in the general population (SIR, 1.01 [95% CI, 0.93-1.09]) and from the risk in the non-IVF group (HR, 1.01 [95% CI, 0.86-1.19]). The cumulative incidences of breast cancer at age 55 were 3.0% for the IVF group and 2.9% for the non-IVF group (P = .85). The SIR did not increase with longer time since treatment (>/=20 years) in the IVF group (0.92 [95% CI, 0.73-1.15]) or in the non-IVF group (1.03 [95% CI, 0.82-1.29]). Risk was significantly lower for those who underwent 7 or more IVF cycles (HR, 0.55 [95% CI, 0.39-0.77]) vs 1 to 2 IVF cycles and after poor response to the first IVF cycle (HR, 0.77 [95% CI, 0.61-0.96] for /=4 collected oocytes). CONCLUSIONS AND RELEVANCE: Among women undergoing fertility treatment in the Netherlands between 1980 and 1995, IVF treatment compared with non-IVF treatment was not associated with increased risk of breast cancer after a median follow-up of 21 years. Breast cancer risk among IVF-treated women was also not significantly different from that in the general population. These findings are consistent with absence of a significant increase in long-term risk of breast cancer among IVF-treated women
The disparity of priapulid, archaeopriapulid and palaeoscolecid worms in the light of new data
Priapulids and their extinct relatives, the archaeopriapulids and palaeoscolecids, are vermiform, carnivorous ecdysozoans with an armoured, extensible proboscis. These worms were an important component of marine communities during the Palaeozoic, but were especially abundant and diverse in the Cambrian. Today, they comprise just seven genera in four families. Priapulids were among the first groups used to test hypotheses concerning the morphological disparity of Cambrian fossils relative to the extant fauna. A previous study sampled at the generic level, concluding that Cambrian genera embodied marginally less morphological diversity than their extant counterparts. Here, we sample predominantly at the species level and include numerous fossils and some extant forms described in the last fifteen years. Empirical morphospaces for priapulids, archaeopriapulids and palaeoscolecids are relatively insensitive to changes in the taxon or character sample: their overall form has altered little, despite the markedly improved sampling. Cambrian and post-Cambrian genera occupy adjacent rather than broadly overlapping regions of these spaces, and Cambrian species still show lower morphological disparity than their post-Cambrian counterparts. Crucially, the significance of this difference has increased with improved taxon sampling over research time. In contrast with empirical morphospaces, the phylogeny of priapulids, archaeopriapulids and palaeoscolecids derived from morphological characters is extremely sensitive to details of taxon sampling and the manner in which characters are weighted. However, the extant Priapulidae and Halicryptidae invariably resolve as sister families, with this entire clade subsequently being sister group to the Maccabeidae. In our most inclusive trees, the extant Tubiluchidae are separated from these other living taxa by a number of small, intervening fossil clades