400 research outputs found

    Applied Radiation and Isotopes Monte Carlo Verification of Output Correction Factors for a TrueBeam STx linac

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    The recent publication of the new code of practice IEAA/AAPM TRS-483 introduces the use of output correction factors to correct the changes in detector response in relative dosimetry of small photon beams. In TRS-483, average correction factors are reported for several detectors at 6 and 10 MV with and without attening. These correction factors were determined by Monte Carlo simulation or experimental measurements using several linacs of di erent brands and vendors. The goal of this work was to validate the output correction factors reported in TRS-483 for a 6 MV (with and without attening lter) of a TrueBeam STx® linac with Monte Carlo simulation for four radiation detectors employed in the dosimetry of small photon beams and whose output correction factors were determined using di erent radiation source than TrueBeam STx®: PTW®31010, PTW®31016, IBA®CC-01, and IBA®SFD. The results show that Monte Carlo calculated output factors, and those reported in the code of practice TRS-483 fully agree within 1%. The use of generic correction factors for a TrueBeam STx® and the detectors studied in this work is adequate for small dosimetry static beams within the uncertainties of Monte Carlo calculations and output correction factors reported in TRS-483. Key words: TRS-483, Monte Carlo simulation, output correction factors, detector model, Phase Space File, Latent Varianc

    Using Connected Vehicle Data to Reassess Dilemma Zone Performance of Heavy Vehicles

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    The rate of fatalities at signalized intersections involving heavy vehicles is nearly five times higher than for passenger vehicles in the US. Previous studies in the US have found that heavy vehicles are twice as likely to violate a red light compared with passenger vehicles. Current technologies leverage setback detection to extend green time for a particular phase and are based upon typical deceleration rates for passenger cars. Furthermore, dilemma zone detectors are not effective when the max out time expires and forces the onset of yellow. This study proposes the use of connected vehicle (CV) technology to trigger force gap out (FGO) before a vehicle is expected to arrive within the dilemma zone limit at max out time. The method leverages position data from basic safety messages (BSMs) to map-match virtual waypoints located up to 1,050 ft in advance of the stop bar. For a 55 mph approach, field tests determined that using a 6 ft waypoint radius at 50 ft spacings would be sufficient to match 95% of BSM data within a 5% lag threshold of 0.59 s. The study estimates that FGOs reduce dilemma zone incursions by 34% for one approach and had no impact for the other. For both approaches, the total dilemma zone incursions decreased from 310 to 225. Although virtual waypoints were used for evaluating FGO, the study concludes by recommending that trajectory-based processing logic be incorporated into controllers for more robust support of dilemma zone and other emerging CV applications

    Reporting Framework for Arterial-Level Traffic Signal Performance Measures Estimated from Connected Vehicle Trajectory Data

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    Traffic signal performance measures based on connected vehicle (CV) trajectory data can provide practitioners actionable information on the operational state of their systems. Agencies need visualization tools that can enable them to quickly assess arterial-level performance by time-of-day (TOD) to identify challenges and opportunities. This document presents a framework to report four signal performance measures over a corridor for all relevant movements, including traditional Highway Capacity Manual (HCM) level of service (LOS), arrivals on green (AOG), split failures (SF), and downstream blockage (DSB). The reporting framework can provide up to 3,072 performance data points per intersection since it provides information for eight different movements and four performance measures for every 15-minute period over 24 hours. To demonstrate implementation, 14 reports displaying performance estimations for 12 corridors, located in 11 different states, are presented. This reporting approach can facilitate the determination of possible mitigation strategies by contrasting operational conditions between movements by TOD

    Extraction of Vehicle CAN Bus Data for Roadway Condition Monitoring

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    Obtaining timely information across the state roadway network is important for monitoring the condition of the roads and operating characteristics of traffic. One of the most significant challenges in winter roadway maintenance is identifying emerging or deteriorating conditions before significant crashes occur. For instance, almost all modern vehicles have accelerometers, anti-lock brake (ABS) and traction control systems. This data can be read from the Controller Area Network (CAN) of the vehicle, and combined with GPS coordinates and cellular connectivity, can provide valuable on-the-ground sampling of vehicle dynamics at the onset of a storm. We are rapidly entering an era where this vehicle data can provide an agency with opportunities to more effectively manage their systems than traditional procedures that rely on fixed infrastructure sensors and telephone reports. This data could also reduce the density of roadway weather information systems (RWIS), similar to how probe vehicle data has reduced the need for micro loop or side fire sensors for collecting traffic speeds

    Bioactive Withanolides from Withania obtusifolia

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    Seven withanolides were isolated from the leaves of Withania obtusifolia. Of these, one was new [obtusifonolide (1)], five were new to the species [sitoindoside IX (2), 6a-chloro-5ß-hydroxy withaferin A (3), isowithanone (4), 2,3-dihydro-3-ethoxywithaferin A (5), and daturataturin A (6)], and one was reported previously from W. obtusifolia [withaferin A (7)]. The structures were elucidated using a set of spectroscopic and spectrometric techniques. Compounds (1–7) were evaluated for cytotoxicity against a human cancer cell panel and for antimicrobial activity in an array of bacteria and fungi. Compound 7 showed cytotoxic activity against the MDA-MB-435 (human melanoma) and SW-620 (human colon cancer) cell lines with IC50 values of 1.7 and 0.3 µM, respectively. The in vitro activity of 7 on 17ß-hydroxysteroid dehydrogenase and 5a-reductase was also investigated

    Connected Vehicle Corridor Deployment and Performance Measures for Assessment

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    In November 2016, the American Association of State Highway and Transportation Officials (AASHTO) announced the Signal Phase and Timing (SPaT) challenge to state and local agencies to kick start infrastructure deployments for V2I communications. The challenge involved the deployment of Dedicated Short Range Communication (DSRC) infrastructure with SPaT broadcasts (current intersection signal light phase) on at least 20 signalized intersections in all of the 50 states by 2020. Although the roadmap for agencies to partner with the automotive industry is still evolving, it is important for Indiana to not only support the SPaT challenge, but also identify mutually beneficial opportunities for INDOT to partner with the automotive industry as Indiana has the second largest automotive related Gross Domestic Product (GDP) in the country. During this study, connected traffic signal infrastructure was deployed at several locations around the state. The West Lafayette corridor SPaT message deployment was done using both traditional Dedicated Short Range Communication (DSRC) as well cellular communication. This report details the deployment locations, the various public and private sector stakeholders that were engaged during the field testing, and several vehicle-infrastructure communication experiments that were used to evaluate connected vehicle use cases. The findings of this research were as follows: The team successfully demonstrated use cases for placing virtual vehicle detection calls to a traffic signal controller using SPaT messages and evaluated latency. The team developed a scalable methodology for characterizing the probability of a traffic signal phase changing by time of day. This methodology of using agency traffic signal data for green light prediction and engine shut down at red lights is particularly useful to the automotive industry. The team successfully demonstrated that split failures, reduced roadway friction and hard braking events can be identified on the vehicle and transmitted to an agency. This enhanced probe data information is particularly valuable to agencies for identifying traffic signal timing problems, segments impacted by winter weather and location where drivers are encountering roadway conditions required hard braking. DSRC provides the lowest latency communication, but in general commercial cellular interface between vehicles and infrastructure provided acceptable latency for most use cases. For most applications, the team believes a commercial cellular interface between vehicles and infrastructure is the most scalable and feasible for an agency to maintain

    Integration of Probe Data Tools into TMC Operations

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    With the advent of probe data, there is a need to virtualize many of the Traffic Management Center (TMC) tools used for analyzing work zones, severe crashes, winter operations, moving maintenance operations, and providing dashboards characterizing overall system mobility. Traditional tools have evolved over the past several years and it is important to develop training materials and make them more accessible to a broad range of Indiana Department of Transportation (INDOT) users and other stakeholder. Over the past several years, agencies have used probe data, mainly 1-minute aggregated segment-based probe data to assess and manage roadways. This study extended traditional segment-based probe data concepts to include enhanced trajectory-based connected vehicle (CV) data, which provides anonymous individual vehicle waypoints at a reporting interval of 3 seconds within a 1.5-meter fidelity radius. The study discusses some of the near-term opportunities, nationwide scalability, and some of the limitations of trajectory data for managing roadways and infrastructure assessment. The tools developed in this study will assist INDOT and other stakeholders in visualizing interstate queues, identifying back-of-queue hard braking events and crashes, identifying alternate diversions during incidents and road closures, enhancing agile management of work zones, estimating traffic signal performance measures without infrastructure investment, and understanding the impact of construction diversions on traffic signals performance

    Chemoinformatic Expedition of the Chemical Space of Fungal Products

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    Aim: Fungi are valuable resources for bioactive secondary metabolites. However, the chemical space of fungal secondary metabolites has been studied only on a limited basis. Herein, we report a comprehensive chemoinformatic analysis of a unique set of 207 fungal metabolites isolated and characterized in a USA National Cancer Institute funded drug discovery project. Results: Comparison of the molecular complexity of the 207 fungal metabolites with approved anticancer and nonanticancer drugs, compounds in clinical studies, general screening compounds and molecules Generally Recognized as Safe revealed that fungal metabolites have high degree of complexity. Molecular fingerprints showed that fungal metabolites are as structurally diverse as other natural products and have, in general, drug-like physicochemical properties. Conclusion: Fungal products represent promising candidates to expand the medicinally relevant chemical space. This work is a significant expansion of an analysis reported years ago for a smaller set of compounds (less than half of the ones included in the present work) from filamentous fungi using different structural properties

    Scaffold Diversity of Fungal Metabolites

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    Many drug discovery projects rely on commercial compounds to discover active leads. However, current commercial libraries, with mostly synthetic compounds, access a small fraction of the possible chemical diversity. Natural products, in contrast, possess a vast structural diversity and have proven to be an outstanding source of new drugs. Several chemoinformatic analyses of natural products have demonstrated their diversity and structural complexity. However, to our knowledge, the scaffold content and structural diversity of fungal secondary metabolites have never been studied. Herein, the scaffold diversity of 223 fungal metabolites was measured and compared to the diversity of approved drugs and commercial libraries for HTS containing natural, synthetic, and semi-synthetic compounds. In addition, the global diversity of the fungal isolates was assessed and compared to other reference data sets using Consensus Diversity Plots, a chemoinformatic tool recently developed. It was concluded that fungal secondary metabolites are cyclic systems with few ramifications and more diverse than the commercial libraries with natural products and semi-synthetic compounds. The fungal metabolites data set was one of the most structurally diverse, containing a large proportion of different and unique scaffolds not found in the other compound data sets including ChEMBL. Therefore, fungal metabolites offer a rich source of molecules suited for identifying diverse candidates for drug discovery

    Innovative Ventures for Student Mobility of the Americas

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    The project “Innovative Ventures for student mobility in the Americas” was generally aim to generate a channel for the exchange of students at West Virginia University (WVU) United States and the National University of Asunción (UNA) of Paraguay. the methodology used in the screening process was through a public tender, using psychometric tests, individual interviews and an essay about the interests of students. the main results obtained were the mobility of students, research in the area environmental, international experience, cultural learning, knowledge about environmental and energy scenarios for the US and Paraguay and interaction of student groups and community institutions. It is concluded based on the reports of students and assessment coordinators from both universities that experience helped broaden the vision of future professionals and to target in the medium term; perform master’s degrees and specializations in universities abroad. It is recommended that the A further promote exchange innovative projects aimed at international accreditation so as to establish the exchange of undergraduate and graduate for the benefit of the university and the country
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