Geometric Quantization of Topological Gauge Theories

We study the symplectic quantization of Abelian gauge theories in $2+1$ space-time dimensions with the introduction of a topological Chern-Simons term.Comment: 13 pages, plain TEX, IF/UFRJ/9

Fragment-Based Identification of Ligands for Bromodomain-Containing Factor 3 of Trypanosoma Cruzi

The Trypanosoma cruzi (T. cruzi) parasite is the cause of Chagas disease, a neglected disease endemic in South America. The life cycle of the T. cruzi parasite is complex and includes transitions between distinct life stages. This change in phenotype (without a change in genotype) could be controlled by epigenetic regulation, and might involve the bromodomain-containing factors 1-5 (TcBDF1-5). However, little is known about the function of the TcBDF1-5. Here we describe a fragment-based approach to identify ligands for T. cruzi bromodomain-containing factor 3 (TcBDF3). We expressed a soluble construct of TcBDF3 in E. coli, and used this to develop a range of biophysical assays for this protein. Fragment screening identified twelve compounds that bind to the TcBDF3 bromodomain. Based on this screen, we developed functional ligands containing a fluorescence or 19F reporter group, and a photo-crosslinking probe for TcBDF3. These tools compounds will be invaluable in future studies on the function of TcBDF3 and will provide insight into the biology of T. cruzi

Fragment-Based Identification of Ligands for Bromodomain-Containing Factor 3 of Trypanosoma cruzi

The Trypanosoma cruzi (T. cruzi) parasite is the cause of Chagas disease, a neglected disease endemic in South America. The life cycle of the T. cruzi parasite is complex and includes transitions between distinct life stages. This change in phenotype (without a change in genotype) could be controlled by epigenetic regulation, and might involve the bromodomain-containing factors 1–5 (TcBDF1–5). However, little is known about the function of the TcBDF1–5. Here we describe a fragment-based approach to identify ligands for T. cruzi bromodomain-containing factor 3 (TcBDF3). We expressed a soluble construct of TcBDF3 in E. coli, and used this to develop a range of biophysical assays for this protein. Fragment screening identified 12 compounds that bind to the TcBDF3 bromodomain. On the basis of this screen, we developed functional ligands containing a fluorescence or 19F reporter group, and a photo-crosslinking probe for TcBDF3. These tool compounds will be invaluable in future studies on the function of TcBDF3 and will provide insight into the biology of T. cruzi

The measurement of visual acuity in children: an evidence-based update

Over the past decade, a number of large clinical trials have provided important information relating to the reliability and repeatability of commonly used paediatric tests of vision and their role in the diagnosis and management of paediatric ocular diseases. The aim of this review is to summarise recent findings on the use of paediatric visual acuity tests in clinical practice and to discuss the validity and accuracy of visual acuity measurements in infants and young children. We provide a broad overview of the benefits and challenges of measuring visual acuity in children and then discuss age-appropriate tests for measuring visual acuity in infants through to school-age children. We also discuss normative values for visual acuity in each age group and, where possible, provide comparisons of results between tests with a particular focus on the importance of optotype design. </p