661 research outputs found
Tantalum Surgical Clip Presenting As an Intraorbital Foreign Body
This is a Photo Essay and does not have an abstract. Please download the PDF or view the article in HTML
Psychometric Properties of the PSVT:R Outcome Measure: A Preliminary Study of Introductory Engineering Design Graphics
The Purdue Spatial Visualization Tests: Visualization of Rotations (PVST:R)is among the most commonly used measurement instruments to assess spatial ability. This paper presents the preliminary findings of a factor analysis of the PSVT:R given to 335 introductory engineering design graphics students. Psychometric analysis of the student sample data indicated alternate loading patterns, divergent from a single factor solution
Development of a multivariable risk model integrating urinary cell DNA methylation and cell-free RNA data for the detection of significant prostate cancer
Background: Prostate cancer exhibits severe clinical heterogeneity and there is a critical need for clinically implementable tools able to precisely and noninvasively identify patients that can either be safely removed from treatment pathways or those requiring further follow up. Our objectives were to develop a multivariable risk prediction model through the integration of clinical, urine-derived cell-free messenger RNA (cf-RNA) and urine cell DNA methylation data capable of noninvasively detecting significant prostate cancer in biopsy naĂŻve patients. Methods: Post-digital rectal examination urine samples previously analyzed separately for both cellular methylation and cf-RNA expression within the Movember GAP1 urine biomarker cohort were selected for a fully integrated analysis (n = 207). A robust feature selection framework, based on bootstrap resampling and permutation, was utilized to find the optimal combination of clinical and urinary markers in a random forest model, deemed ExoMeth. Out-of-bag predictions from ExoMeth were used for diagnostic evaluation in men with a clinical suspicion of prostate cancer (PSA â„ 4 ng/mL, adverse digital rectal examination, age, or lower urinary tract symptoms). Results: As ExoMeth risk score (range, 0-1) increased, the likelihood of high-grade disease being detected on biopsy was significantly greater (odds ratio = 2.04 per 0.1 ExoMeth increase, 95% confidence interval [CI]: 1.78-2.35). On an initial TRUS biopsy, ExoMeth accurately predicted the presence of Gleason score â„3 + 4, area under the receiver-operator characteristic curve (AUC) = 0.89 (95% CI: 0.84-0.93) and was additionally capable of detecting any cancer on biopsy, AUC = 0.91 (95% CI: 0.87-0.95). Application of ExoMeth provided a net benefit over current standards of care and has the potential to reduce unnecessary biopsies by 66% when a risk threshold of 0.25 is accepted. Conclusion: Integration of urinary biomarkers across multiple assay methods has greater diagnostic ability than either method in isolation, providing superior predictive ability of biopsy outcomes. ExoMeth represents a more holistic view of urinary biomarkers and has the potential to result in substantial changes to how patients suspected of harboring prostate cancer are diagnosed
Diffusive behavior for randomly kicked Newtonian particles in a spatially periodic medium
We prove a central limit theorem for the momentum distribution of a particle
undergoing an unbiased spatially periodic random forcing at exponentially
distributed times without friction. The start is a linear Boltzmann equation
for the phase space density, where the average energy of the particle grows
linearly in time. Rescaling time, the momentum converges to a Brownian motion,
and the position is its time-integral showing superdiffusive scaling with time
. The analysis has two parts: (1) to show that the particle spends
most of its time at high energy, where the spatial environment is practically
invisible; (2) to treat the low energy incursions where the motion is dominated
by the deterministic force, with potential drift but where symmetry arguments
cancel the ballistic behavior.Comment: 55 pages. Some typos corrected from previous versio
A Brownian particle in a microscopic periodic potential
We study a model for a massive test particle in a microscopic periodic
potential and interacting with a reservoir of light particles. In the regime
considered, the fluctuations in the test particle's momentum resulting from
collisions typically outweigh the shifts in momentum generated by the periodic
force, and so the force is effectively a perturbative contribution. The
mathematical starting point is an idealized reduced dynamics for the test
particle given by a linear Boltzmann equation. In the limit that the mass ratio
of a single reservoir particle to the test particle tends to zero, we show that
there is convergence to the Ornstein-Uhlenbeck process under the standard
normalizations for the test particle variables. Our analysis is primarily
directed towards bounding the perturbative effect of the periodic potential on
the particle's momentum.Comment: 60 pages. We reorganized the article and made a few simplifications
of the conten
The glacial geomorphology of the western cordilleran ice sheet and Ahklun ice cap, Southern Alaska
During the late Wisconsinan, Southern Alaska was covered by two large ice masses; the western arm of the Cordilleran Ice Sheet and the Ahklun Mountains Ice Cap. Compared to the other ice sheets that existed during this period (e.g. the British-Irish, Laurentide and Fennoscandian ice sheets), little is known about the geomorphology they left behind. This limits our understanding of their flow pattern and retreat. Here we present systematic mapping of the glacial geomorphology of the two ice masses which existed in Southern Alaska. Due to spatially variable data availability, mapping was conducted using digital elevation models and satellite images of varying resolutions. Offshore, we map the glacial geomorphology using available bathymetric data. For the first time, we document >5000 subglacial lineations, recording ice flow direction. The distribution of moraines is presented, as well as features related to glacial meltwater drainage patterns (eskers and meltwater channels). Prominent troughs were also mapped on Alaska's continental shelf. This map provides the data required for a glacial inversion of these palaeo-ice masses
Be-10 age constraints on latest Pleistocene and Holocene cirque glaciation across the western United States
Paleoclimate: A rocky reworking of Holocene glaciology New dating of glacially-deposited rocks substantially revises our understanding of the waxing and waning of ice since the last glacial maximum. Glaciologists have long thought that moraines throughout the western United States represent âneoglacialâ advances about 6,000 years ago. Now, a multi-institution team led by Shaun Marcott at the University of Wisconsin-Madison has found â using cosmogenic isotopes â that these terminal deposits left by advancing glaciers are instead 9,000 to 15,000 years old. The research advances prior work by using absolute, not relative ages, and documents that glaciers retreated after the last glacial maximum ~ 21,000 years ago, fluctuated locally throughout much of the Holocene, and re-advanced during the Little Ice Age of a few hundred years ago. Glacial advances that might have occurred during the neoglacial were wiped away by the more extensive glaciations of the Little Ice Age
Nonclassic lipoid congenital adrenal hyperplasia masquerading as familial glucocorticoid deficiency
Context: Familial glucocorticoid deficiency (FGD) is an autosomal recessive disorder resulting from resistance to the action of ACTH on the adrenal cortex. Affected individuals are deficient in cortisol and, if untreated, are likely to succumb to hypoglycemia and/or overwhelming infection. Mutations of the ACTH receptor (MC2R) and the melanocortin 2 receptor accessory protein (MRAP), FGD types 1 and 2 respectively, account for approximately 45% of cases.
Objective: A locus on chromosome 8 has previously been linked to the disease in three families, but no underlying gene defect has to date been identified.
Design: The study design comprised single-nucleotide polymorphism genotyping and mutation detection.
Setting: The study was conducted at secondary and tertiary referral centers.
Patients: Eighty probands from families referred for investigation of the genetic cause of FGD participated in the study.
Interventions: There were no interventions.
Results: Analysis by single-nucleotide polymorphism array of the genotype of one individual with FGD previously linked to chromosome 8 revealed a large region of homozygosity encompassing the steroidogenic acute regulatory protein gene, STAR. We identified homozygous STAR mutations in this patient and his affected siblings. Screening of our total FGD patient cohort revealed homozygous STAR mutations in a further nine individuals from four other families.
Conclusions: Mutations in STAR usually cause lipoid congenital adrenal hyperplasia, a disorder characterized by both gonadal and adrenal steroid deficiency. Our results demonstrate that certain mutations in STAR (R192C and the previously reported R188C) can present with a phenotype indistinguishable from that seen in FGD
Common Representation of Information Flows for Dynamic Coalitions
We propose a formal foundation for reasoning about access control policies
within a Dynamic Coalition, defining an abstraction over existing access
control models and providing mechanisms for translation of those models into
information-flow domain. The abstracted information-flow domain model, called a
Common Representation, can then be used for defining a way to control the
evolution of Dynamic Coalitions with respect to information flow
Regulation of T-Cell Apoptosis by Sequences Encoded at the Luca-15 Candidate Tumour Suppressor Locus
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