804 research outputs found

    A Long Baseline Laser Strainmeter for the Exploratory Studies Facility at Yucca Mountain

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    This Scientific Investigation Plan (SIP), for work under the second Department of Energy/University and Community College System of Nevada (DOE/UCCSN) Cooperative Agreement (10/01/03), DEFC28- 04RW12232, is intended to cover the laser strainmeter operation and monitoring task being conducted by the University of California, San Diego (UCSD), under the oversight of the Nevada Seismological Laboratory of the University of Nevada-Reno (NSL/UNR). UCSD has carried out the design, engineering, and installation of the east-west laser strainmeter (LSM) currently in place in the Exploratory Studies Facility (ESF) at Yucca Mountain

    Longbase laser strainmeter measurements from the South Ramp of the Yucca Mountain facility

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    Under subcontract (DOE/UCCSN DE-FC28-98NV12081, Task 7) from the Seismological Laboratory of the University of Nevada-Reno, the University of California, San Diego (UCSD), has designed, installed, and operated a laser strainmeter (LSM) in the Exploratory Studies Facility (ESF) at Yucca Mountain, Nevada. This instrument provides precise deformation monitoring of the (proposed) repository block. This document describes the history of the installation, outlines the principles of operation of the system, documents the integral recording and control system and file formats used, and provides information on how QA has been implemented, with the aim of being a self-contained description which could be used (in conjunction with the data files at the TDMS) to understand the measurements made by the LSM. Appendix A gives the unique digital signatures for all data files submitted to the TDMS. The instrument was installed along the south wall of the tunnel, between 69+46 m and 65+41 m (tunnel coordinates). The resulting azimuth (91°) provides good sensitivity to the posited long-term strains from geologic sources. Designing an instrument for the tunnel was a challenge, as was installing it, given the usual, strict local operating procedures; these two elements combined to increase substantially the overall time to completion, though the experience gained has put us in a good position for further work in this setting. We have fully documented (SN) all aspects of the installation, and have complete engineering plans of the LSM available (Appendix B). The instrument began operating to QA standards on 2002:233 (August 21, 2002), and has recorded strain since that time, though with interruptions caused by the very strong shaking from the mining trains, which both caused sizeable gaps in the series and caused the lasers to degrade much more rapidly: both problems have been dealt with successfully. The instrument is producing quality records. Preliminary results from the laser strainmeter suggest that seismic waves and tides cause strains with no obvious anomalous response or nonlinearity; and that air-pressure changes can cause significant strains, with a response that depends on the spatial pattern of pressure applied. With the data so far available, we can constrain the long-term strain rate to be less than 0.2 /z£/yr. A longer-term record should greatly improve this constraint

    Dual Action Additives for Jet A-1: Fuel Dehydrating Icing Inhibitors

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    © 2016 American Chemical Society. A novel approach for protecting jet fuel against the effects of water contamination based upon Fuel Dehydrating Icing Inhibitors (FDII) is presented. This dual-action strategy is predicated on the addition of a fuel-soluble water scavenger that undergoes a kinetically fast hydrolysis reaction with free water to produce a hydrophilic ice inhibitor, thereby further militating against the effects of water crystallization. Criteria for an optimum FDII were identified and then used to screen a range of potential water-scavenging agents, which led to a closer examination of systems based upon exo/endo-cyclic ketals and both endo- and exo-cyclic ortho esters. The ice inhibition properties of the subsequent products of the hydrolysis reaction in Jet A-1 were screened by differential scanning calorimetry. The hydrolysis products of 2-methoxy-2-methyl-1,3-dioxolane demonstrate similar ice inhibition performance to DiEGME over a range of blend levels. The calorific values for the products of hydrolysis were also investigated, and it is clear that there would be a significant fuel saving on use of the additive over current fuel system icing inhibitors. Finally, three promising candidates, 2-methoxy-2-methyl-1,3-dioxolane, 2-methoxy-2-methyl-1,3-dioxane, and 2-methoxy-2,4,5-trimethyl-1,3-dioxolane, were shown to effectively dehydrate Jet A-1 at room temperature over a 2 h period

    The National Childrens Study: Recruitment Outcomes Using the Provider-Based Recruitment Approach

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    In 2009, the National Children’s Study (NCS) Vanguard Study tested the feasibility of household-based recruitment and participant enrollment using a birth-rate probability sample. In 2010, the NCS Program Office launched 3 additional recruitment approaches. We tested whether provider-based recruitment could improve recruitment outcomes compared with household-based recruitment

    Characterization of patients who present with insomnia : is there room for a symptom cluster-based approach?

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    Study Objectives: This study examined empirically derived symptom cluster profiles among patients who present with insomnia using clinical data and polysomnography. Methods: Latent profile analysis was used to identify symptom cluster profiles of 175 individuals (63% female) with insomnia disorder based on total scores on validated self-report instruments of daytime and nighttime symptoms (Insomnia Severity Index, Glasgow Sleep Effort Scale, Fatigue Severity Scale, Beliefs and Attitudes about Sleep, Epworth Sleepiness Scale, Pre-Sleep Arousal Scale), mean values from a 7-day sleep diary (sleep onset latency, wake after sleep onset, and sleep efficiency), and total sleep time derived from an in-laboratory PSG. Results: The best-fitting model had three symptom cluster profiles: "High Subjective Wakefulness" (HSW), "Mild Insomnia" (MI) and "Insomnia-Related Distress" (IRD). The HSW symptom cluster profile (26.3% of the sample) reported high wake after sleep onset, high sleep onset latency, and low sleep efficiency. Despite relatively comparable PSG-derived total sleep time, they reported greater levels of daytime sleepiness. The MI symptom cluster profile (45.1%) reported the least disturbance in the sleep diary and questionnaires and had the highest sleep efficiency. The IRD symptom cluster profile (28.6%) reported the highest mean scores on the insomnia-related distress measures (eg, sleep effort and arousal) and waking correlates (fatigue). Covariates associated with symptom cluster membership were older age for the HSW profile, greater obstructive sleep apnea severity for the MI profile, and, when adjusting for obstructive sleep apnea severity, being overweight/obese for the IRD profile. Conclusions: The heterogeneous nature of insomnia disorder is captured by this data-driven approach to identify symptom cluster profiles. The adaptation of a symptom cluster-based approach could guide tailored patient-centered management of patients presenting with insomnia, and enhance patient care

    The role of iron in the pathogenesis of endometriosis: a systematic review

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    Abstract STUDY QUESTION What is the role of iron in the pathophysiology of endometriosis? SUMMARY ANSWER Iron excess is demonstrated wherever endometriotic tissues are found and is associated with oxidative stress, an inflammatory microenvironment and cell damage; the iron-mediated oxidative stress is independently linked to subfertility, symptom severity and malignant transformation. WHAT IS KNOWN ALREADY Iron is found in excess in endometriotic tissues, and multiple mechanisms have been studied and posited to explain this. It is clear that iron excess plays a vital role in promoting oxidative stress and cell damage. The evidence base is large, but no comprehensive reviews exist to summarise our understanding and highlight the overarching themes to further our understanding and suggest future directions of study for the field. STUDY DESIGN, SIZE, DURATION This systematic review with a thematic analysis retrieved studies from the PubMed, Embase, Web of Science and Cochrane Library databases and searches were conducted from inception through to August 2022. Human and animal studies published in the English language were included and identified using a combination of exploded MeSH terms (‘Iron’ and ‘Endometriosis’) and free-text search terms (‘Iron’, ‘Ferric’, ‘Ferrous’, ‘Endometriosis’, ‘Endometrioma’). PARTICIPANTS/MATERIALS, SETTING, METHODS This review was reported in accordance with the PRISMA guidelines. All studies reporting original data concerning the role of iron or iron complexes in the pathophysiology of endometriosis were included. Studies which did not report original data or provided a review of the field were excluded. Bias analysis was completed for each included study by using the Newcastle-Ottawa scoring system. MAIN RESULTS AND THE ROLE OF CHANCE There were 776 records identified and these were screened down to 53 studies which met the eligibility criteria, including 6 animal and 47 human studies, with 3,556 individual participants. Iron excess is demonstrated in various tissues and fluids, including ovarian endometriomas, ovarian follicles, ectopic endometriotic lesions and peritoneal fluid. Markers of oxidative stress are strongly associated with high iron levels, and aberrant expression of iron-transport proteins has been demonstrated. Abnormal resistance to ferroptosis is likely. Iron-mediated oxidative stress is responsible for a pro-inflammatory micro-environment and is linked to subfertility, symptom severity and, possibly, malignant transformation. LIMITATIONS, REASONS FOR CAUTION A minority of the included studies were of objectively low quality with a high-risk of bias and may lead to misleading conclusions. Additionally, multiple studies failed to appropriately characterise the included patients by known confounding variables such as menstrual cycle phase, which may introduce bias to the findings. WIDER IMPLICATIONS OF THE FINDINGS Current literature depicts a central role of aberrant iron mechanics and subsequent oxidative stress in endometriosis. It is likely that iron excess is at least partly responsible for the persistence and proliferation of ectopic endometriotic lesions. As such, iron mechanics represent an attractive target for novel therapeutics, including iron chelators or effectors of the iron-oxidative stress pathway. There are significant gaps in our current understanding, and this review highlights and recommends several topics for further research. These include the role of iron chelation, resistance to ferroptosis, the relationship between iron excess and localised hypoxia, systemic iron pathophysiology in endometriosis, and the role of oxidative stress in malignant transformation. STUDY FUNDING/COMPETING INTEREST(S) J.W and S.P are supported by clinical fellowships at Liverpool University Hospital NHS Foundation trust. No additional funding was requested or required for the completion of this work. C.J.H. is supported by a Wellbeing of Women project grant (RG2137). D.K.H. is supported by a Wellbeing of Women project grant (RG2137) and MRC clinical research training fellowship (MR/V007238/1). The authors have no conflicts of interest to declare. REGISTRATION NUMBER A protocol was prospectively registered with the PROSPERO database in August 2021 (CRD42021272818) </jats:sec
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