Ranjith Pathegama Gamage

Modelling of intact and jointed mudstone samples under uniaxial and triaxial compression

Rock mass is a highly complex entity where the strength and deformation behaviour can be significantly affected by its secondary structures such as joints, fissures and bedding planes. Whilst many research works have been conducted to study the behaviour of a specific rock mass, a thorough understanding of its strength and deformation behaviour incorporating different joint sets has not been established. In this study, a comprehensive numerical modelling using a three-dimensional distinct element code, 3DEC, was undertaken to study the strength and deformation behaviour of a mudstone, locally found in Melbourne, in unconfined and confined states. The initial unconfined model established for intact mudstone was calibrated against the well-established laboratory-based empirical strength relationships and subsequently compared with some strength test data available for field samples. The intact unconfined model was then extended to study the strength behaviour in the confined state. The results obtained from this confined intact model were compared with existing strength criteria and were found in good agreement. The confined model was extended further to investigate the effects of joint sets and dip angles on the rock mass strength and deformation behaviour by incorporating two different joint configurations (one-joint and two-joint) with varying dip angles (0°–90°). This study found that the rock mass strength in a confined state varied significantly between the two joint configurations.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), first reported case from Sri Lanka

Disrupted-In-Schizophrenia (DISC1) is a candidate susceptibility gene for major psychiatric diseases including schizophrenia, depression and bipolar disorder, while biological roles of the DISC1 protein have not yet been fully explained. In the present study, a 129 substrain-specific 25-bp deletion in exon 6 of Disc1 that introduces a termination codon at exon 7 and abolishes production of the full-length protein was transferred to the C57BL/6J genetic background. We used behavioral assays to assess Disc1-deficient mice for depression-like behaviors. Immobility time in the forced swimming test and the tail suspension test was comparable between wildtype and Disc1-null mice. Brain sections of Disc1-deficient mice were examined in the microscopy. Gross brain morphology appeared normal in Disc1-null mice. Immunofluorescent staining was performed to compare the expression pattern of DISC1-related proteins in wild-type and Disc1-deficient mice. Further analysis of mice carrying the 129 substrain-derived deletion variant might help to explain how DISC1 variation contributes to susceptibility in humans.