X-ray free-electron lasers provide novel opportunities to conduct single particle analysis on nanoscale particles. Coherent diffractive imaging experiments were performed at the Linac Coherent Light Source (LCLS), SLAC National Laboratory, exposing single inorganic core-shell nanoparticles to femtosecond hard-X-ray pulses. Each facetted nanoparticle consisted of a crystalline gold core and a differently shaped palladium shell. Scattered intensities were observed up to about 7 nm resolution. Analysis of the scattering patterns revealed the size distribution of the samples, which is consistent with that obtained from direct real-space imaging by electron microscopy. Scattering patterns resulting from single particles were selected and compiled into a dataset which can be valuable for algorithm developments in single particle scattering research.
Viral protein U (Vpu) is a type-III integral membrane protein encoded by Human Immunodeficiency Virus-1 (HIV- 1). It is expressed in infected host cells and plays several roles in viral progeny escape from infected cells, including down-regulation of CD4 receptors. But key structure/function questions remain regarding the mechanisms by which the Vpu protein contributes to HIV-1 pathogenesis. Here we describe expression of Vpu in bacteria, its purification and characterization. We report the successful expression of PelB-Vpu in Escherichia coli using the leader peptide pectate lyase B (PelB) from Erwinia carotovora. The protein was detergent extractable and could be isolated in a very pure form. We demonstrate that the PelB signal peptide successfully targets Vpu to the cell membranes and inserts it as a type I membrane protein. PelB-Vpu was biophysically characterized by circular dichroism and dynamic light scattering experiments and was shown to be an excellent candidate for elucidating structural models.
Using improv comedy skills to entertain students and keep their attention.
Survey instrument used in Survey of Academic Library Streaming Video Revisited, 2015
Explains the urgent need for libraries to engage in preservation of irreplaceable content on VHS and other obsolete video formats in their collections, and presents a database of titles for which due diligence as required by Section 108 of US Copyright has already been completed.
In spring 2013, the presenters developed a survey on academic library streaming video and distributed it broadly through various discussion and mailing lists.
This is the first large-scale and most comprehensive effort to date to collect data on streaming video funding, licensing, acquisition, and hosting in academic libraries. Its results will provide benchmark data for future explorations of this rapidly expanding approach to video in academic libraries.
Streaming video is becoming a common occurrence on many campuses today. Its fast growth is due in part to the steady growth of online classes and programs. Technology has also played a role in this growth as alternatives for ingesting and accessing content have expanded. Multiple options are now available including in-house approaches, cloud storage, and third party vendors.
This survey collected data on how academic institutions address the day-to-day operations related to streaming video as well as perceived directions for future action.
Survey questions addressed selection and acquisition of video in both hard copy and streaming formats, funding for acquisitions, current and planned hosting interfaces, cataloging and access, and current practice and policy on digitization of hard copy titles for streaming. This session reviews the instrument used, and provides a preliminary look at some of the key data collected.