Impact Fracture of Composite and Homogeneous Nanoagglomerates

It is not yet clear on whether the fracture characteristics of structured composite capsules and homogeneous nanoagglomerates differ significantly under impact loading conditions. Experimental measurement of impact fracture properties of such small agglomerates is difficult, due to the length and time scales associated with this problem. Using computer simulations, here we show that nanoagglomerates are subjected to normal impact loading fracture within a few nanoseconds in a brittle manner. The restitution coefficient of the nanoagglomerates varies nonlinearly with initial kinetic energy. The fracture of nanoagglomerates does not always happen at the moment when they experience the maximum wall force, but occurs after a time lag of a few nanoseconds as characterised by impact survival time (IST) and IST index. IST is dependant on the initial kinetic energy, mechanical and geometric properties of the nanoagglomerates. For identical geometries of the capsules, IST index is higher for capsules with a soft shell than for these with a hard shell, an indication of the enhanced ability of the soft nanocapsules to dissipate impact energy. The DEM simulations reported here based on theories of contact mechanics provide fundamental insights on the fracture behaviour of agglomerates—at nanoscale, the structure of the agglomerates significantly influences their breakage behaviour

A survey on the occurrence of resistance to anthelmintics of gastrointestinal nematodes of goats in Mozambique

A survey to study the extent of anthelmintic resistance was conducted in Maputo and Gaza, two of the ten provinces of Mozambique, during February and March 1999. A total of 12 flocks, six in Maputo and six in Gaza, was surveyed. The faecal egg count reduction test was used to assess the efficacy of three anthelmintics most often used in Mozambique, namely albendazole fenbendazole and levamisole. The degree of resistance was calculated using two different methods, and varied according to the method used. Using the formula of Coles, Bauer, Borgsteede, Geerts, Klei, Taylor and Waller (1992), resistance to the benzimidazoles was detected in one flock in Maputo and one in Gaza, and to levamisole in three flocks in Maputo and one in Gaza. When the formula of Dash, Hall and Barger (1988) was used, however, resistance to the benzimidazoles was detected in only one flock in Maputo, and no resistance to levamisole was detected. The 12 farms surveyed were too few for conclusions to be made on the prevalence of anthelmintic resistance in goats in Mozambique as a whole. Therefore, an extensive survey at national level is needed. This study gives evidence, however, that anthelmintic resistance in nematode parasites of goats is an emerging problem, to which special attention should be paid.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Swedish International Development and Cooperation Agency (SIDA).mn201

Exploring Ligand Binding to Calcitonin Gene-Related Peptide Receptors

Class B1 G protein-coupled receptors (GPCRs) are important targets for many diseases, including cancer, diabetes, and heart disease. All the approved drugs for this receptor family are peptides that mimic the endogenous activating hormones. An understanding of how agonists bind and activate class B1 GPCRs is fundamental for the development of therapeutic small molecules. We combined supervised molecular dynamics (SuMD) and classic molecular dynamics (cMD) simulations to study the binding of the calcitonin gene-related peptide (CGRP) to the CGRP receptor (CGRPR). We also evaluated the association and dissociation of the antagonist telcagepant from the extracellular domain (ECD) of CGRPR and the water network perturbation upon binding. This study, which represents the first example of dynamic docking of a class B1 GPCR peptide, delivers insights on several aspects of ligand binding to CGRPR, expanding understanding of the role of the ECD and the receptor-activity modifying protein 1 (RAMP1) on agonist selectivity