Adaptive Optimisation of Illumination Beam Profiles in Fluorescence Microscopy

Wide-field fluorescence microscope techniques such as single/selective plane illumination microscope (SPIM) are typically configured to image large regions of a sample at once. Here the illumination beam provides uniform excitation of several biological features across the region, `sliced' to a thickness of between 5-10 microns. In this paper we propose a simple alteration to the optical configuration of a SPIM by switching the light-sheet- forming cylindrical lens with a spatial light modulator. This has the potential to adaptively reconfigure the light sheet geometry to improve the optical sectioning of specific biological features, rather than the thicker sectioning of several features at once across a larger observation field-of-view. We present a prototype version of such a system, referred to as an Adaptive-SPIM (A-SPIM) system. We then suggest that the direct recording of illumination beam shapes within the working microscope system can better facilitate the analysis and subsequent re-configuration of the illumination beam to a specific geometry, and summarise the design and operation of a device that we have developed specifically for this purpose. We finally present reconstructed quantitative three dimensional flux maps of illumination beams from three microscope configurations taken using this miniature high-dynamic range beam profiling device, comparing the beam geometry of a regular SPIM system with our prototype A-SPIM system, and suggesting future improvements

Arab Siege of Egyptian Babylon : a Classic Study in Islamic Expansion of the 7th Century

The fall of the Byzantine Fortress of Babylon in 641ce allowed invading Arab armies to move beyond the Lower Nile region of Egypt and ultimately conquer the whole of the province from the Byzantines, effectively ending centuries of almost totally uninterrupted Roman rule. The paper examines this pivotal moment in Islamic history in order to identify four salient features of early Islamic expansion: the struggle of the early caliphate for power and authority; the role of religion; the development of an organized and effective military; the nature of early Islamic approaches to warfare and foreign policy

Patient-reported depression measures in cancer: a meta-review

The patient-reported depression measures that perform best in oncology settings have not yet been identified. We did a meta-review to integrate the findings of reviews of more than 50 depression measures used in adults with, or recovering from, any type of cancer. We searched Medline, PsycINFO, Embase, and grey literature from 1999 to 2014 to identify 19 reviews representing 372 primary studies. 11 reviews were rated as being of high quality (defined as meeting at least 20 criteria in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement). The Hospital Anxiety Depression Scale (HADS) was the most thoroughly evaluated measure, but was limited by cutpoint variability. The HADS had moderate screening utility indices and was least recommended in advanced cancer or palliative care. The Beck Depression Inventory was more generalisable across cancer types and disease stages, with good indices for screening and case finding. The Center for Epidemiologic Studies Depression Scale was the best-weighted measure in terms of responsiveness. This meta-review provides a comprehensive overview of the strengths and limitations of available depression measures. It can inform the choice of the best measure for specific settings and purposes

Confined nanorods: jamming due to helical buckling

We investigate a longitudinally loaded elastic nanorod inside a cylindrical channel and show within the context of classical elasticity theory that the Euler buckling instability leads to a helical postbuckling form of the rod within the channel. The local pitch of the confined helix changes along the channel and so does the longitudinal force transmitted along the rod, diminishing away from the loaded end. This creates a possibility of jamming of the nanorod within the channel.Comment: 8 pages, 8 figure

Energy and Economy: Recognizing High-Energy Modernity as a Historical Period

This introduction to Economic Anthropology’s special issue on “Energy and Economy” argues that we might find inspiration for a much more engaged and public anthropology in an unlikely place—19th century evolutionist thought. In addition to studying the particularities of energy transitions, which anthropology does so well, a more engaged anthropology might also broaden its temporal horizons to consider the nature of the future “stage” into which humanity is hurtling in an era of resource depletion and climate change. Net energy (EROEI), or the energy “surplus” on which we build and maintain our complex societal arrangements, is a key tool for anthropologists as we bring our trademark cross-cultural, ethnographically grounded knowledge and perspectives to bear in examining the complex interplay of material infrastructures, energy flows, social organization, and culture. We are now mindful of the always already cultural nature of such circuitry and interactions—in ways obviously unavailable to our nineteenth-century forebears. And yet even as our energy futures are neither predetermined nor inevitable, neither are they as unfettered by material constraints as many have come to think. A robust anthropology of energy informed by awareness of the energetic basis of the historically specific moment in which we find ourselves seems poised to help us get beyond the developmentalist ideas of Morgan and Tylor and to overcome a seeming inability to think comprehensively about the human predicament in simultaneously general and particular terms. We have a chance in the space now opening to get beyond the antinomies—materialist—mentalist, infrastructure—superstructure, agency—structure, objective—subjective, and so on—that dominated much of twentieth-century anthropology

Prospectus, October 27, 1999

https://spark.parkland.edu/prospectus_1999/1027/thumbnail.jp

Quantitative High Dynamic Range Beam Proling for Fluorescence Microscopy

Modern developmental biology relies on optically-sectioning uorescence microscope techniques to produce non-destructive in-vivo images of developing specimens at high resolution in three dimensions. As optimal performance of these techniques is reliant on the three-dimensional (3-D) intensity prole of the illumination employed, the ability to directly record and analyze these proles is of great use to the uorescence microscopist or instrument builder. Though excitation beam proles can be measured indirectly using a sample of uorescent beads and recording the emission along the microscope detection path, we demonstrate an alternative approach where a miniature camera sensor is used directly within the illumination beam. Measurements taken using our approach are solely concerned with the illumination optics as the detection optics are not involved. We present a miniature beam proling device and high dynamic range ux reconstruction algorithm that together are capable of accurately reproducing quantitative 3-D ux maps over a large focal volume. Performance of this beam proling system is veried within an optical test bench and demonstrated for uorescence microscopy by proling the low NA illumination beam of a single plane illumination microscope. The generality and success of this approach showcases a widely- exible beam amplitude diagnostic tool for use within the life sciences

Adaptive optimisation of illumination beam profiles in fluorescence microscopy

Wide-field fluorescence microscope techniques such as single/selective plane illumination microscope (SPIM) are typically configured to image large regions of a sample at once. Here the illumination beam provides uniform excitation of several biological features across the region, `sliced' to a thickness of between 5-10 microns. In this paper we propose a simple alteration to the optical configuration of a SPIM by switching the light-sheet- forming cylindrical lens with a spatial light modulator. This has the potential to adaptively reconfigure the light sheet geometry to improve the optical sectioning of specific biological features, rather than the thicker sectioning of several features at once across a larger observation field-of-view. We present a prototype version of such a system, referred to as an Adaptive-SPIM (A-SPIM) system. We then suggest that the direct recording of illumination beam shapes within the working microscope system can better facilitate the analysis and subsequent re-configuration of the illumination beam to a specific geometry, and summarise the design and operation of a device that we have developed specifically for this purpose. We finally present reconstructed quantitative three dimensional flux maps of illumination beams from three microscope configurations taken using this miniature high-dynamic range beam profiling device, comparing the beam geometry of a regular SPIM system with our prototype A-SPIM system, and suggesting future improvements