70 research outputs found

    Experimental investigation of interface states and photovoltaic effects on the scanning capacitance microscopy measurement for p-n junction dopant profiling

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    Controlled polishing procedures were used to produce both uniformly doped and p-n junction silicon samples with different interface state densities but identical oxide thicknesses. Using these samples, the effects of interface states on scanning capacitance microscopy (SCM) measurements could be singled out. SCM measurements on the junction samples were performed with and without illumination from the atomic force microscopy laser. Both the interface charges and the illumination were seen to affect the SCM signal near p-n junctions significantly. SCM p-n junction dopant profiling can be achieved by avoiding or correctly modeling these two factors in the experiment and in the simulation. (c) 2005 American Institute of Physics

    Seprase: An overview of an important matrix serine protease

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    Seprase or Fibroblast Activation Protein (FAP) is an integral membrane serine peptidase, which has been shown to have gelatinase activity. Seprase has a dual function in tumour progression. The proteolytic activity of Seprase has been shown to promote cell invasiveness towards the ECM and also to support tumour growth and proliferation. Seprase appears to act as a proteolytically active 170-kDa dimer, consisting of two 97- kDa subunits. It is a member of the group type II integral serine proteases, which includes dipeptidyl peptidase IV (DPPIV/CD26) and related type II transmembrane prolyl serine peptidases, which exert their mechanisms of action on the cell surface. DPPIV and Seprase exhibit multiple functions due to their abilities to form complexes with each other and to interact with other membrane-associated molecules. Localisation of these protease complexes at cell surface protrusions, called invadopodia, may have a prominent role in processing soluble factors and in the degradation of extracellular matrix components that are essential to the cellular migration and matrix invasion that occur during tumour invasion, metastasis and angiogenesis

    Structural Analysis of Prolyl Oligopeptidases Using Molecular Docking and Dynamics: Insights into Conformational Changes and Ligand Binding

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    Prolyl oligopeptidase (POP) is considered as an important pharmaceutical target for the treatment of numerous diseases. Despite enormous studies on various aspects of POPs structure and function still some of the questions are intriguing like conformational dynamics of the protein and interplay between ligand entry/egress. Here, we have used molecular modeling and docking based approaches to unravel questions like differences in ligand binding affinities in three POP species (porcine, human and A. thaliana). Despite high sequence and structural similarity, they possess different affinities for the ligands. Interestingly, human POP was found to be more specific, selective and incapable of binding to a few planar ligands which showed extrapolation of porcine POP in human context is more complicated. Possible routes for substrate entry and product egress were also investigated by detailed analyses of molecular dynamics (MD) simulations for the three proteins. Trajectory analysis of bound and unbound forms of three species showed differences in conformational dynamics, especially variations in β-propeller pore size, which was found to be hidden by five lysine residues present on blades one and seven. During simulation, β-propeller pore size was increased by ∼2 Å in porcine ligand-bound form which might act as a passage for smaller product movement as free energy barrier was reduced, while there were no significant changes in human and A. thaliana POPs. We also suggest that these differences in pore size could lead to fundamental differences in mode of product egress among three species. This analysis also showed some functionally important residues which can be used further for in vitro mutagenesis and inhibitor design. This study can help us in better understanding of the etiology of POPs in several neurodegenerative diseases

    Life with Birds: an archaeology of war and loss in the suburbs

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    Life with Birds is an investigation of the disjunction between public and private experiences of the Vietnam war and its aftermath. The creative non-fiction component of the thesis juxtaposes historical documents with family stories, photographs and memories in order to situate military history in the home and disrupt the binaries around dominant war tropes, such as the heroic/traumatic binary. It focuses on the everyday, the small scale and the ordinary as worthy of historical and cultural attention and aims to redress the silences and erasures in bureaucracies, archives and within families by reimagining or repopulating them with found materials, a combination of information, observation and guesswork. This lyric methodology was developed using concepts of Toni Morrison’s ‘literary archaeology’, Marianne Hirsch’s ‘postmemory’ and Hélène Cixous’ l’écriture féminine, as well as Claudia Rankine’s deployment of the lyric form in Citizen. The exegesis examines writings and discourses around war in Australia that erase the experiences and legacy of certain war veterans and their families, including mine. In it I discuss the disconnect between national mythologisation and commemoration of Anzac and Vietnam veterans and the lived experiences of veteran families, such as impacts of war trauma, bureaucratic intransigence and veteran health and suicide. This thesis highlights the ongoing negotiations between public and private lives in an attempt to broaden the conversation around the invisible or erased impacts of war in Australia, particularly for women and the children of war veterans

    Calibration of the NBS Calibrated Hot Box

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