1,130 research outputs found

    Thermoluminescent dosimetry for LDEF experiment M0006

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    Experiment M0006 on the Long Duration Exposure Facility had as its objective the investigation of space radiation effects on various electronic and optical components, as well as on seed germination. The Grumman Corporate Research Center provided the radiation dosimetric measurements for M0006, comprising the preparation of thermoluminescent dosimeters (TLD) and the subsequent measurement and analysis of flight exposed and control samples. In addition, various laboratory exposures of TLD's with gamma rays and protons were performed to obtain a better understanding of the flight exposures

    IMPACT OF MENTAL HEALTH–RELATED UNPLANNED LOSSES ONBOARD SURFACE SHIPS

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    The Surface Navy is experiencing increased unplanned losses (UPL) each year. In this interpretive study, we received and analyzed data from Naval Surface Forces Pacific Command (CNSP), looking for trends and patterns. Our data covered fiscal years 2019, 2020, 2021, and up to February 2022. The data showed that over the last two years, mental health has overtaken misconduct and drug abuse for the leading cause of UPLs across the Fleet. Upon this discovery, we questioned why mental health UPLs were rising and how we can reduce them. Currently, the term “unplanned loss” is undefined in any instruction. A previous study defined a UPL as “a loss to a command where a Sailor is issued a DD214." However, we believe it should be defined as “any loss of a Sailor from a command that is expected to last greater than 3 weeks.” By defining the term this way, it will allow commands to implement a standard operating procedure and corrective courses of actions to find a replacement Sailor and to account for temporary losses. We believe filling UPLs as quickly as possible will significantly slow down the domino effect of multiple UPLs onboard surface ships. Our research uncovered more question than answers, but we believe our recommendations and future research will greatly benefit the Fleet in the future.Lieutenant, United States NavyLieutenant, United States NavyApproved for public release. Distribution is unlimited

    A model of the spatial tumour heterogeneity in colorectal adenocarcinoma tissue

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    Background There have been great advancements in the field of digital pathology. The surge in development of analytical methods for such data makes it crucial to develop benchmark synthetic datasets for objectively validating and comparing these methods. In addition, developing a spatial model of the tumour microenvironment can aid our understanding of the underpinning laws of tumour heterogeneity. Results We propose a model of the healthy and cancerous colonic crypt microenvironment. Our model is designed to generate synthetic histology image data with parameters that allow control over cancer grade, cellularity, cell overlap ratio, image resolution, and objective level. Conclusions To the best of our knowledge, ours is the first model to simulate histology image data at sub-cellular level for healthy and cancerous colon tissue, where the cells have different compartments and are organised to mimic the microenvironment of tissue in situ rather than dispersed cells in a cultured environment. Qualitative and quantitative validation has been performed on the model results demonstrating good similarity to the real data. The simulated data could be used to validate techniques such as image restoration, cell and crypt segmentation, and cancer grading.BBSRC and University of Warwick Institute of Advanced Study. QNRF grant NPRP 5-1345-1-228

    A stochastic polygons model for glandular structures in colon histology images

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    In this paper, we present a stochastic model for glandular structures in histology images of tissue slides stained with Hematoxylin and Eosin, choosing colon tissue as an example. The proposed Random Polygons Model (RPM) treats each glandular structure in an image as a polygon made of a random number of vertices, where the vertices represent approximate locations of epithelial nuclei. We formulate the RPM as a Bayesian inference problem by defining a prior for spatial connectivity and arrangement of neighboring epithelial nuclei and a likelihood for the presence of a glandular structure. The inference is made via a Reversible-Jump Markov chain Monte Carlo simulation. To the best of our knowledge, all existing published algorithms for gland segmentation are designed to mainly work on healthy samples, adenomas, and low grade adenocarcinomas. One of them has been demonstrated to work on intermediate grade adenocarcinomas at its best. Our experimental results show that the RPM yields favorable results, both quantitatively and qualitatively, for extraction of glandular structures in histology images of normal human colon tissues as well as benign and cancerous tissues, excluding undifferentiated carcinomas

    From Soldier to Student II: Assessing Campus Programs for Veterans and Service Members

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    The United States is in the process of bringing more than 2 million service members home from Iraq and Afghanistan and reducing the size of America's military. Today's veterans are the beneficiaries of the Post-9/11 GI Bill, which has provided unprecedented financial support for attending college. More than 500,000 veterans and their families have utilized Post-9/11 GI Bill benefits since the law's enactment in 2008. Many returning veterans -- as well as service members in the active and reserve components of the armed forces -- will enroll in higher education to enhance their job prospects, achieve career goals, expand their knowledge and skill sets for both personal and career enrichment, and facilitate their transition to civilian life.How well prepared is higher education to serve these new students, and what changes has it made in response to the first wave of Post-9/11 GI Bill recipients on campus? Despite the long history of veterans' education benefits and presence of veteran students on campus, current research is still catching up to the veteran and military student population. This report represents the second assessment of the current state of programs and services for veterans and service members on campuses across the nation, based on survey results from 690 institutions

    Posterior Vitreous Detachment and the Posterior Hyaloid Membrane

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    PURPOSE: Despite posterior vitreous detachment being a common ocular event affecting most individuals in an aging population, there is little consensus regarding its precise anatomic definition. We investigated the morphologic appearance and molecular composition of the posterior hyaloid membrane to determine whether the structure clinically observed enveloping the posterior vitreous surface after posterior vitreous detachment is a true basement membrane and to postulate its origin. Understanding the relationship between the vitreous (in both its attached and detached state) and the internal limiting membrane of the retina is essential to understanding the cause of rhegmatogenous retinal detachment and vitreoretinal interface disorders, as well as potential future prophylactic and treatment strategies. DESIGN: Clinicohistologic correlation study. PARTICIPANTS: Thirty-six human donor globes. METHODS: Vitreous bodies identified to have posterior vitreous detachment were examined with phase-contrast microscopy and confocal microscopy after immunohistochemically staining for collagen IV basement membrane markers, in addition to extracellular proteins that characterize the vitreoretinal junction (fibronectin, laminin) and vitreous gel (opticin) markers. The posterior retina similarly was stained to evaluate the internal limiting membrane. Findings were correlated to the clinical appearance of the posterior hyaloid membrane observed during slit-lamp biomicroscopy after posterior vitreous detachment and compared with previously published studies. MAIN OUTCOME MEASURES: Morphologic appearance and molecular composition of the posterior hyaloid membrane. RESULTS: Phase-contrast microscopy consistently identified a creased and distinct glassy membranous sheet enveloping the posterior vitreous surface, correlating closely with the posterior hyaloid membrane observed during slit-lamp biomicroscopy in patients with posterior vitreous detachment. Immunofluorescent confocal micrographs demonstrated the enveloping membranous structure identified on phase-contrast microscopy to show positive stain results for type IV collagen. Immunofluorescence of the residual intact internal limiting membrane on the retinal surface also showed positive stain results for type IV collagen. CONCLUSIONS: The results of this study provide immunohistochemical evidence that the posterior hyaloid membrane is a true basement membrane enveloping the posterior hyaloid surface. Because this membranous structure is observed only after posterior vitreous detachment, the results of this study indicate that it forms part of the internal limiting membrane when the vitreous is in its attached state

    Development of Low-Cost Micromanipulation Systems for Small Extraterrestrial Samples

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    The analysis of microscale to mm-scale astromaterials often involves the transfer of samples from storage or collection substrates to analytical substrates. These transfers are accomplished by hand (via tweezers or fine-tipped needles) or by utilizing micromanipulation instruments. Freehand manipulation of small particles is extremely challenging due to involuntary hand tremors on the order of 100m and due to the triboelectric charging induced by frequent contact between the manipulation tool and the support substrate. Months or years of practice may be required before an investigator develops the necessary experience to confidently transfer a 10-20m particle in this manner. Handling even mm-sized particles with fine-tipped tweezers can be challenging, due to the inability to precisely control the force with which grains are being held. Mechanical, hydraulic, and motorized/electrical micromanipulators enable the precise handling of microscale samples and are often utilized in laboratories where frequent small sample preparation is required. However, the price of such instruments (~ 10,000to10,000 to 100,000) makes them cost-prohibitive for some institutions. Graduate students or early-career scientists interested in conducting research on interplanetary dust particles, Itokawa particles returned by Hayabusa, or future samples returned by OSIRIS-REx or Hayabusa2 may experience difficulty in justifying the expense of a micromanipulator to their advisors or principle investigators. Johnson Space Centers Astromaterials Acquisition and Curation Office and the Lunar and Planetary Institute conduct annual training for early career scientists and for investigators that require experience with handling of small extraterrestrial samples. In support of this training, we have been developing low-cost mechanical alternatives to expensive micromanipulators that training participants can implement in their respective facilities

    Deep Burn Develpment of Transuranic Fuel for High-Temperature Helium-Cooled Reactors - July 2010

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    The DB Program Quarterly Progress Report for April - June 2010, ORNL/TM/2010/140, was distributed to program participants on August 4. This report discusses the following: (1) TRU (transuranic elements) HTR (high temperature helium-cooled reactor) Fuel Modeling - (a) Thermochemical Modeling, (b) 5.3 Radiation Damage and Properties; (2) TRU HTR Fuel Qualification - (a) TRU Kernel Development, (b) Coating Development, (c) ZrC Properties and Handbook; and (3) HTR Fuel Recycle - (a) Recycle Processes, (b) Graphite Recycle, (c) Pyrochemical Reprocessing - METROX (metal recovery from oxide fuel) Process Development
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