168 research outputs found

    Scaling by 5 on a 1/4-Cantor Measure

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    Each Cantor measure (\mu) with scaling factor 1/(2n) has at least one associated orthonormal basis of exponential functions (ONB) for L^2(\mu). In the particular case where the scaling constant for the Cantor measure is 1/4 and two specific ONBs are selected for L^2(\mu), there is a unitary operator U defined by mapping one ONB to the other. This paper focuses on the case in which one ONB (\Gamma) is the original Jorgensen-Pedersen ONB for the Cantor measure (\mu) and the other ONB is is 5\Gamma. The main theorem of the paper states that the corresponding operator U is ergodic in the sense that only the constant functions are fixed by U.Comment: 34 page

    Augmented realityā€“assisted microsurgical resection of brain arteriovenous malformations: illustrative case

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    Background: Arteriovenous malformations (AVMs) of the brain are vessel conglomerates of feeding arteries and draining veins that carry a risk of spontaneous and intraoperative rupture. Augmented reality (AR)-assisted neuronavigation permits continuous, real-time, updated visualization of navigation information through a heads-up display, thereby potentially improving the safety of surgical resection of AVMs. Observations: The authors report a case of a 37-year-old female presenting with a 2-year history of recurrent falls due to intermittent right-sided weakness and increasing clumsiness in the right upper extremity. Magnetic resonance imaging, magnetic resonance angiography, and cerebral angiography of the brain revealed a left parietal Spetzler-Martin grade III AVM. After endovascular embolization of the AVM, microsurgical resection using an AR-assisted neuronavigation system was performed. Postoperative angiography confirmed complete obliteration of arteriovenous shunting. The postsurgical course was unremarkable, and the patient remains in excellent health. Lessons: Our case describes the operative setup and intraoperative employment of AR-assisted neuronavigation for AVM resection. Application of this technology may improve workflow and enhance patient safety

    Global biomarkers of oxidative stress and fractures: a matched case-control study

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    BackgroundEvidence for a relationship between oxidative stress and osteoporotic fractures in humans is limited. Fluorescent oxidation products (FlOPs, excitation/emission wavelengths 320/420nm denoted FlOP_320; 360/420nm [FlOP_360]; and 400/475nm [FlOP_400]) are global biomarkers of oxidative stress, and reflect oxidative damage to proteins, phospholipids, and nucleic acids. We investigated the association between FlOPs and a recent osteoporotic fracture.MethodsWe conducted a case-control study in a Chinese population aged 50 years or older. A recent osteoporotic fracture in the cases was confirmed by x-ray. Cases were matched with community-based non-fracture controls (1:2 ratio) for age (Ā± 4 years) and sex. In addition, we conducted a sensitivity unmatched case-control study which included all fracture cases and all eligible non-fracture controls prior to matching. Plasma FlOPs were measured with a fluorescent microplate reader. We used unconditional logistic regression to analyze the association between FlOPs (per 1-SD increase in logarithmic scale) and fracture; odds ratios (OR) and 95% confidence intervals (95% CI) were reported.ResultsForty-four cases and 88 matched controls (mean age: 68.2 years) were included. After covariate adjustment (i.e., body mass index, physical activity, and smoking), higher FlOP_360 (OR = 1.85; 95% CI = 1.03 ā€“ 3.34) and FlOP_400 (OR = 13.29; 95% CI = 3.48 ā€“ 50.69) levels, but not FlOP_320 (OR = 0.56; 95% CI = 0.27 ā€“ 1.15), were associated with increased fracture risk. Subgroup analyses by fracture site and unmatched case-control study found comparable associations of FlOP_360 and FlOP_400 with hip and non-hip fractures.ConclusionsHigher FlOP_360 and FlOP_400 levels were associated with increased risk of fracture, and this association was comparable for hip and non-hip fractures. Prospective studies are warranted to confirm this finding

    972-107 L-Arginine Decreases Infarct Size in Rats Exposed to Environmental Tobacco Smoke

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    We previously showed that environmental tobacco smoke (ETS) increased myocardial infarct size in a rat model of ischemia and reperfusion. If reduced reperfusion was caused by endothelial cell damage and increased vascular tone, we postulated that L-arginine (ARG) would increase nitric oxide and better protect the heart. 60 rats were randomly divided into 4 groups: ETS or Control (C) with and without ARG (2.25% ARG in drinking water). The ETS groups were exposed (4 Marlboro cigarettes per 15 minutes. 6 hours a day) for 6 weeks. During ETS-exposure, average air nicotine, carbon monoxide and total particulate concentrations were 1304 Ī¼g/m3, 78 ppm and 31 mg/m3, respectively. After 6 weeks, all rats were subjected to 35 min LAD occlusion (0) and 120 min reperfusion, with hemodynamic monitoring via the carotid artery. Aortic rings were harvested to evaluate vascular reactivity. Infarct size (infarct mass/risk area x 100%) decreased significantly in the ETS with ARG group compared to the ETS without ARG group. There were no significant differences among groups in heart rate (HR), systolic pressure (SP), and rate pressure product. Tlere were positive correlations between infarct size and heart rates from baseline to reperfusion 120 min (r = 0.4-0.6. p = 0.01-0.001). There was no relationship between vascular reactivity and infarct size.GroupNo. of RatsInf/LV (%)Inf/RA (%)0-35ā€™HR (beats/m)0-35'SP (mmHg)Max Relax (%)C1125Ā±351Ā±6408Ā±11120Ā±784Ā±11C+ ARG1025Ā±252Ā±3415Ā±10103Ā±11112Ā±15ETS1034Ā±464Ā±6427Ā±16108Ā±8128Ā±16ETS + ARG1122Ā±3*42Ā±6*410Ā±17106Ā±10127Ā±18Values are MeansĀ±SEM*p<0.05, p values from two-way ANOVAConclusionL-arginine decreases myocardial infarct size after ischemia and reperfusion in ETS-exposed rats. This effect does not appear to be secondary to alterations in hemodynamics

    Criteria for the use of omics-based predictors in clinical trials.

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    The US National Cancer Institute (NCI), in collaboration with scientists representing multiple areas of expertise relevant to 'omics'-based test development, has developed a checklist of criteria that can be used to determine the readiness of omics-based tests for guiding patient care in clinical trials. The checklist criteria cover issues relating to specimens, assays, mathematical modelling, clinical trial design, and ethical, legal and regulatory aspects. Funding bodies and journals are encouraged to consider the checklist, which they may find useful for assessing study quality and evidence strength. The checklist will be used to evaluate proposals for NCI-sponsored clinical trials in which omics tests will be used to guide therapy

    Criteria for the use of omics-based predictors in clinical trials: explanation and elaboration

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    Abstract High-throughput ā€˜omicsā€™ technologies that generate molecular profiles for biospecimens have been extensively used in preclinical studies to reveal molecular subtypes and elucidate the biological mechanisms of disease, and in retrospective studies on clinical specimens to develop mathematical models to predict clinical endpoints. Nevertheless, the translation of these technologies into clinical tests that are useful for guiding management decisions for patients has been relatively slow. It can be difficult to determine when the body of evidence for an omics-based test is sufficiently comprehensive and reliable to support claims that it is ready for clinical use, or even that it is ready for definitive evaluation in a clinical trial in which it may be used to direct patient therapy. Reasons for this difficulty include the exploratory and retrospective nature of many of these studies, the complexity of these assays and their application to clinical specimens, and the many potential pitfalls inherent in the development of mathematical predictor models from the very high-dimensional data generated by these omics technologies. Here we present a checklist of criteria to consider when evaluating the body of evidence supporting the clinical use of a predictor to guide patient therapy. Included are issues pertaining to specimen and assay requirements, the soundness of the process for developing predictor models, expectations regarding clinical study design and conduct, and attention to regulatory, ethical, and legal issues. The proposed checklist should serve as a useful guide to investigators preparing proposals for studies involving the use of omics-based tests. The US National Cancer Institute plans to refer to these guidelines for review of proposals for studies involving omics tests, and it is hoped that other sponsors will adopt the checklist as well.http://deepblue.lib.umich.edu/bitstream/2027.42/134536/1/12916_2013_Article_1104.pd

    Impact of American Joint Committee on Cancer Eighth Edition clinical stage and smoking history on oncologic outcomes in human papillomavirusā€associated oropharyngeal squamous cell carcinoma

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    BackgroundThe purpose of this study was to evaluate the AJCC eighth edition clinical staging system for human papillomavirus (HPV)ā€associated oropharyngeal squamous cell carcinoma and to further understand how clinical stage and smoking history affect oncologic outcomes. The purpose of this study was to present the understanding of how clinical stage and smoking history affect oncologic outcomes in human papillomavirus (HPV)ā€associated oropharyngeal squamous cell carcinoma (SCC) is critical for selecting patients for treatment deintensification.MethodsKaplanā€Meier and Cox regression were used to evaluate overall survival (OS), locoregional recurrenceā€free survival (LRFS), and distant recurrenceā€free survival (DRFS). Concordance statistics (Cā€indices) were used to compare discriminating ability.ResultsThe OS and DRFS but not LRFS were significantly distributed using the American Joint Committee on Cancer (AJCC) seventh and eighth editions criteria. The Cā€indices for OS, LRFS, and DRFS were 0.57, 0.54, and 0.60, respectively, using the AJCC seventh edition, and 0.63, 0.53, and 0.65, respectively, using the AJCC eighth edition. On multivariate analysis, 1ā€‰+ā€‰packā€year smoking history correlated with OS (hazard ratio [HR] 1.96; 95% confidence interval [CI] 1.2ā€3.1; Pā€‰<ā€‰.01) but not LRFS or DRFS.ConclusionThese results support implementation of the AJCC eighth edition for HPVā€associated oropharyngeal SCC. Clinical stage may be more important than smoking history in selection for deintensification.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148352/1/hed25336_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148352/2/hed25336.pd
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