188 research outputs found

    Near-IR wide field-of-view Huygens metalens for outdoor imaging applications

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    The ongoing effort to implement compact and cheap optical systems is the main driving force for the recent flourishing research in the field of optical metalenses. Metalenses are a type of metasurface, used for focusing and imaging applications, and are implemented based on the nanopatterning of an optical surface. The challenge faced by metalens research is to reach high levels of performance, using simple fabrication methods suitable for mass-production. In this paper we present a Huygens nanoantenna based metalens, designed for outdoor photographic/surveillance applications in the near-infra-red. We show that good imaging quality can be obtained over a field-of-view (FOV) as large as +/-15 degrees. This first successful implementation of metalenses for outdoor imaging applications is expected to provide insight and inspiration for future metalens imaging applications

    How good is your metalens? Experimental verification of metalens performance criterion

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    A metric for evaluation of overall metalens performance is presented. It is applied to determination of optimal operating spectral range of a metalens, both theoretically and experimentally. This metric is quite general and can be applied to the design and evaluation of future metalenses, particularly achromatic metalenses

    Patterns of Cost for Patients Dying in the Intensive Care Unit and Implications for Cost Savings of Palliative Care Interventions.

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    BACKGROUND: Terminal intensive care unit (ICU) stays represent an important target to increase value of care. OBJECTIVE: To characterize patterns of daily costs of ICU care at the end of life and, based on these patterns, examine the role for palliative care interventions in enhancing value. DESIGN: Secondary analysis of an intervention study to improve quality of care for critically ill patients. SETTING/PATIENTS: 572 patients who died in the ICU between 2003 and 2005 at a Level-1 trauma center. METHODS: Data were linked with hospital financial records. Costs were categorized into direct fixed, direct variable, and indirect costs. Patterns of daily costs were explored using generalized estimating equations stratified by length of stay, cause of death, ICU type, and insurance status. Estimates from the literature of effects of palliative care interventions on ICU utilization were used to simulate potential cost savings under different time horizons and reimbursement models. MAIN RESULTS: Mean cost for a terminal ICU stay was 39.3K ± 45.1K. Direct fixed costs represented 45% of total hospital costs, direct variable costs 20%, and indirect costs 34%. Day of admission was most expensive (mean 9.6K ± 7.6K); average cost for subsequent days was 4.8K ± 3.4K and stable over time and patient characteristics. CONCLUSIONS: Terminal ICU stays display consistent cost patterns across patient characteristics. Savings can be realized with interventions that align care with patient preferences, helping to prevent unwanted ICU utilization at end of life. Cost modeling suggests that implications vary depending on time horizon and reimbursement models

    "The ripples are big": Storying the impact of doping in sport beyond the sanctioned athlete

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    Objective: The purpose of this paper was to extend current doping research efforts by shifting the focus away from a doping-user perspective to examine the experiences of elite athletes that have been personally affected by other athletes doping behaviours. Design: This research works within the interpretive paradigm, adopting relativist ontology and transactional/subjectivist epistemology. Method: Conversational interviews were conducted with ‘competitive’ (N = 2) and ‘retired’ (N = 2) elite Track and Field athletes from multiple countries. In order to communicate the findings in a way that captures the complexity of the issue, whilst also appealing to the athletes this issue affects, creative non-fiction stories were used to present the findings. Results: Two stories were created; one incorporating the ‘competitive’ athletes’ experiences and one presenting the ‘retired’ athletes’ accounts. The stories detail financial, emotional, and relational implications stemming from others’ use of performance enhancing drugs. Critically, the impact is not ephemeral; the retired athletes detailed the long-term implications of their experiences. Meanwhile, the competitive athletes suggest that given the current state of sport, they regularly have to defend their status as ‘clean athletes’. Thus, the ripples of doping in sport appear to be far reaching and enduring. Conclusions: Incorporating a novel mode of knowledge production within the doping literature, the stories presented here demonstrate elite athletes’ candid accounts of being impacted by others’ doping behaviours in sport. This study also emphasises the value of adopting novel and creative approaches to data collection and representation within the field of doping research

    Predictors of Time to Death After Terminal Withdrawal of Mechanical Ventilation in the ICU

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    Little information exists about the expected time to death after terminal withdrawal of mechanical ventilation. We sought to determine the independent predictors of time to death after withdrawal of mechanical ventilation. METHODS: We conducted a secondary analysis from a cluster randomized trial of an end-of-life care intervention. We studied 1,505 adult patients in 14 hospitals in Washington State who died within or shortly after discharge from an ICU following terminal withdrawal of mechanical ventilation (August 2003 to February 2008). Time to death and its predictors were abstracted from the patients' charts and death certificates. Predictors included demographics, proxies of severity of illness, life-sustaining therapies, and International Classification of Diseases, 9th ed., Clinical Modification codes. RESULTS: The median (interquartile range [IQR]) age of the cohort was 71 years (58-80 years), and 44% were women. The median (IQR) time to death after withdrawal of ventilation was 0.93 hours (0.25-5.5 hours). Using Cox regression, the independent predictors of a shorter time to death were nonwhite race (hazard ratio [HR], 1.17; 95% CI, 1.01-1.35), number of organ failures (per-organ HR, 1.11; 95% CI, 1.04-1.19), vasopressors (HR, 1.67; 95% CI, 1.49-1.88), IV fluids (HR, 1.16; 95% CI, 1.01-1.32), and surgical vs medical service (HR, 1.29; 95% CI, 1.06-1.56). Predictors of longer time to death were older age (per-decade HR, 0.95; 95% CI, 0.90-0.99) and female sex (HR, 0.86; 95% CI, 0.77-0.97). CONCLUSIONS: Time to death after withdrawal of mechanical ventilation varies widely, yet the majority of patients die within 24 hours. Subsequent validation of these predictors may help to inform family counseling at the end of life.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85787/1/Cooke - Predictors of time to death after withdrawal.pd

    Role of RecA and the SOS Response in Thymineless Death in Escherichia coli

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    Thymineless death (TLD) is a classic and enigmatic phenomenon, documented in bacterial, yeast, and human cells, whereby cells lose viability rapidly when deprived of thymine. Despite its being the essential mode of action of important chemotherapeutic agents, and despite having been studied extensively for decades, the basic mechanisms of TLD have remained elusive. In Escherichia coli, several proteins involved in homologous recombination (HR) are required for TLD, however, surprisingly, RecA, the central HR protein and activator of the SOS DNA–damage response was reported not to be. We demonstrate that RecA and the SOS response are required for a substantial fraction of TLD. We show that some of the Rec proteins implicated previously promote TLD via facilitating activation of the SOS response and that, of the roughly 40 proteins upregulated by SOS, SulA, an SOS–inducible inhibitor of cell division, accounts for most or all of how SOS causes TLD. The data imply that much of TLD results from an irreversible cell-cycle checkpoint due to blocked cell division. FISH analyses of the DNA in cells undergoing TLD reveal blocked replication and apparent DNA loss with the region near the replication origin underrepresented initially and the region near the terminus lost later. Models implicating formation of single-strand DNA at blocked replication forks, a SulA-blocked cell cycle, and RecQ/RecJ-catalyzed DNA degradation and HR are discussed. The data predict the importance of DNA damage-response and HR networks to TLD and chemotherapy resistance in humans

    Chromatin- and Transcription-Related Factors Repress Transcription from within Coding Regions throughout the Saccharomyces cerevisiae Genome

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    Previous studies in Saccharomyces cerevisiae have demonstrated that cryptic promoters within coding regions activate transcription in particular mutants. We have performed a comprehensive analysis of cryptic transcription in order to identify factors that normally repress cryptic promoters, to determine the amount of cryptic transcription genome-wide, and to study the potential for expression of genetic information by cryptic transcription. Our results show that a large number of factors that control chromatin structure and transcription are required to repress cryptic transcription from at least 1,000 locations across the S. cerevisiae genome. Two results suggest that some cryptic transcripts are translated. First, as expected, many cryptic transcripts contain an ATG and an open reading frame of at least 100 codons. Second, several cryptic transcripts are translated into proteins. Furthermore, a subset of cryptic transcripts tested is transiently induced in wild-type cells following a nutritional shift, suggesting a possible physiological role in response to a change in growth conditions. Taken together, our results demonstrate that, during normal growth, the global integrity of gene expression is maintained by a wide range of factors and suggest that, under altered genetic or physiological conditions, the expression of alternative genetic information may occur
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