64 research outputs found
Clinical commissioning of intensity-modulated proton therapy systems: Report of AAPM Task Group 185
Proton therapy is an expanding radiotherapy modality in the United States and worldwide. With the number of proton therapy centers treating patients increasing, so does the need for consistent, high-quality clinical commissioning practices. Clinical commissioning encompasses the entire proton therapy system\u27s multiple components, including the treatment delivery system, the patient positioning system, and the image-guided radiotherapy components. Also included in the commissioning process are the x-ray computed tomography scanner calibration for proton stopping power, the radiotherapy treatment planning system, and corresponding portions of the treatment management system. This commissioning report focuses exclusively on intensity-modulated scanning systems, presenting details of how to perform the commissioning of the proton therapy and ancillary systems, including the required proton beam measurements, treatment planning system dose modeling, and the equipment needed
A mathematical model of the metabolic and perfusion effects on cortical spreading depression
Cortical spreading depression (CSD) is a slow-moving ionic and metabolic
disturbance that propagates in cortical brain tissue. In addition to massive
cellular depolarization, CSD also involves significant changes in perfusion and
metabolism -- aspects of CSD that had not been modeled and are important to
traumatic brain injury, subarachnoid hemorrhage, stroke, and migraine.
In this study, we develop a mathematical model for CSD where we focus on
modeling the features essential to understanding the implications of
neurovascular coupling during CSD. In our model, the sodium-potassium--ATPase,
mainly responsible for ionic homeostasis and active during CSD, operates at a
rate that is dependent on the supply of oxygen. The supply of oxygen is
determined by modeling blood flow through a lumped vascular tree with an
effective local vessel radius that is controlled by the extracellular potassium
concentration. We show that during CSD, the metabolic demands of the cortex
exceed the physiological limits placed on oxygen delivery, regardless of
vascular constriction or dilation. However, vasoconstriction and vasodilation
play important roles in the propagation of CSD and its recovery. Our model
replicates the qualitative and quantitative behavior of CSD --
vasoconstriction, oxygen depletion, extracellular potassium elevation,
prolonged depolarization -- found in experimental studies.
We predict faster, longer duration CSD in vivo than in vitro due to the
contribution of the vasculature. Our results also help explain some of the
variability of CSD between species and even within the same animal. These
results have clinical and translational implications, as they allow for more
precise in vitro, in vivo, and in silico exploration of a phenomenon broadly
relevant to neurological disease.Comment: 17 pages including 9 figures, accepted by PLoS On
A multi-disciplinary commentary on preclinical research to investigate vascular contributions to dementia
Although dementia research has been dominated by Alzheimer's disease (AD), most dementia in older people is now recognised to be due to mixed pathologies, usually combining vascular and AD brain pathology. Vascular cognitive impairment (VCI), which encompasses vascular dementia (VaD) is the second most common type of dementia. Models of VCI have been delayed by limited understanding of the underlying aetiology and pathogenesis. This review by a multidisciplinary, diverse (in terms of sex, geography and career stage), cross-institute team provides a perspective on limitations to current VCI models and recommendations for improving translation and reproducibility. We discuss reproducibility, clinical features of VCI and corresponding assessments in models, human pathology, bioinformatics approaches, and data sharing. We offer recommendations for future research, particularly focusing on small vessel disease as a main underpinning disorder
A Multi-disciplinary Commentary on Preclinical Research to investigate Vascular Contributions to Dementia
Although dementia research has been dominated by Alzheimer's disease (AD), most dementia in older people is now recognised to be due to mixed pathologies, usually combining vascular and AD brain pathology. Vascular cognitive impairment (VCI), which encompasses vascular dementia (VaD) is the second most common type of dementia. Models of VCI have been delayed by limited understanding of the underlying aetiology and pathogenesis. This review by a multidisciplinary, diverse (in terms of sex, geography and career stage), cross-institute team provides a perspective on limitations to current VCI models and recommendations for improving translation and reproducibility. We discuss reproducibility, clinical features of VCI and corresponding assessments in models, human pathology, bioinformatics approaches, and data sharing. We offer recommendations for future research, particularly focusing on small vessel disease as a main underpinning disorder.</p
The Eighteenth Data Release of the Sloan Digital Sky Surveys: Targeting and First Spectra from SDSS-V
The eighteenth data release of the Sloan Digital Sky Surveys (SDSS) is the
first one for SDSS-V, the fifth generation of the survey. SDSS-V comprises
three primary scientific programs, or "Mappers": Milky Way Mapper (MWM), Black
Hole Mapper (BHM), and Local Volume Mapper (LVM). This data release contains
extensive targeting information for the two multi-object spectroscopy programs
(MWM and BHM), including input catalogs and selection functions for their
numerous scientific objectives. We describe the production of the targeting
databases and their calibration- and scientifically-focused components. DR18
also includes ~25,000 new SDSS spectra and supplemental information for X-ray
sources identified by eROSITA in its eFEDS field. We present updates to some of
the SDSS software pipelines and preview changes anticipated for DR19. We also
describe three value-added catalogs (VACs) based on SDSS-IV data that have been
published since DR17, and one VAC based on the SDSS-V data in the eFEDS field.Comment: Accepted to ApJ
The eighteenth data release of the Sloan Digital Sky Surveys : targeting and first spectra from SDSS-V
The eighteenth data release of the Sloan Digital Sky Surveys (SDSS) is the first one for SDSS-V, the fifth generation of the survey. SDSS-V comprises three primary scientific programs, or "Mappers": Milky Way Mapper (MWM), Black Hole Mapper (BHM), and Local Volume Mapper (LVM). This data release contains extensive targeting information for the two multi-object spectroscopy programs (MWM and BHM), including input catalogs and selection functions for their numerous scientific objectives. We describe the production of the targeting databases and their calibration- and scientifically-focused components. DR18 also includes ~25,000 new SDSS spectra and supplemental information for X-ray sources identified by eROSITA in its eFEDS field. We present updates to some of the SDSS software pipelines and preview changes anticipated for DR19. We also describe three value-added catalogs (VACs) based on SDSS-IV data that have been published since DR17, and one VAC based on the SDSS-V data in the eFEDS field.Publisher PDFPeer reviewe
Open data from the third observing run of LIGO, Virgo, KAGRA and GEO
The global network of gravitational-wave observatories now includes five
detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600.
These detectors collected data during their third observing run, O3, composed
of three phases: O3a starting in April of 2019 and lasting six months, O3b
starting in November of 2019 and lasting five months, and O3GK starting in
April of 2020 and lasting 2 weeks. In this paper we describe these data and
various other science products that can be freely accessed through the
Gravitational Wave Open Science Center at https://gwosc.org. The main dataset,
consisting of the gravitational-wave strain time series that contains the
astrophysical signals, is released together with supporting data useful for
their analysis and documentation, tutorials, as well as analysis software
packages.Comment: 27 pages, 3 figure
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The 16th Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17)
The 16th Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17)
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