570 research outputs found

    Cancer-Related Fatigue Trajectory and Biological Correlates of Acute Lymphoblastic Leukemia Patients During Chemotherapy

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    Pediatric recruitment included a patient with acute lymphocytic leukemia. Blood chemistry and blood indices were analyzed and the patient reported physical, mental, and emotional statuses in a PROMIS questionnaire. At baseline, week 1, week 2, and week 3 Fatigue fluctuated over time while there was a decrease in anxiety, pain, and depression. Suspected fatigue biomarkers were not quantified

    SuperCDMS Detector Readout Cryogenic Hardware

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    SuperCDMS employs 1‐inch thick germanium crystals operated below 50mK in a dilution cryostat. Each detector produces ionization and phonon signals. Ionization signals are amplified by JFETs operating at 150K within an assembly mounted on the 4K cryostat stage. These high impedance signals are carried to the FETs by superconducting “vacuum coaxes” which minimize thermal conductivity, stray capacitance, and microphonics. Transition edge sensors produce low‐impedance phonon signals, amplified by SQUID arrays mounted on a 600mK stage. Detectors are mounted in a six‐sided wiring configuration called a “tower”, which carries signals from 40mK to 4K. A flex circuit 3 meters in length carries amplified signals for each detector from 4K to a vacuum bulkhead. We describe the methods used to support the detectors, wiring and amplifier elements at various thermal stages, minimizing electrical noise and thermal loads

    Evaluating effects of chemical weathering and surface contamination on the in situ provenance analysis of building stones in the Cuzco region of Peru with portable XRF

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    As the only type of instrument capable of determining artifact geochemistry in a wide variety of settings, portable X-Ray Fluorescence (PXRF) may be frequently utilized as probably the best option for collecting data when removal of objects in part or in whole is unfeasible. However, using PXRF in circumstances where sample selection and preparation diverge from standards developed for lab-based instrumentation requires assessing the impact of new and potentially limiting factors to establish the validity of the method in these new contexts. Here we examine the effects of surface contamination and chemical weathering on the ability to assess provenance of igneous building stones used in the Cuzco region of Peru. Surface contamination was assessed through comparing low-impact cleaning methods on diorite and andesite blocks, and weathering was examined by comparing weathered vs. fresh surfaces of samples from two andesite quarries. In general, the lightest elements were most impacted by contamination and weathering while measurements of many of the heavier elements commonly used in provenance studies were relatively unaffected. Concentrations of Pb and Zn were problematic in the urban context of Cuzco because of pollution. Ability to determine provenance of building stones within those limitations (i.e., the validity of this application of PXRF) was demonstrated in a preliminary study by comparing measurements from uncleaned, exposed building stones in the region to fresh quarry samples

    The Cryogenic Dark Matter Search (CDMS) experiment: Results, status and perspective

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    The Cryogenic Dark Matter Search experiment (CDMS) is using Phonon+Ionization detectors to search for Dark Matter in the form of Weakly Interactive Massive Particles (WIMPs). We report on new results from the operation of CDMS five “towers” at Soudan underground laboratory. With new and more massive detectors, SuperCDMS project has been started since March 2009. We report on the current status of SuperCDMS and its perspective

    SuperCDMS Detector Fabrication Advances

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    For its dark matter search the SuperCDMS collaboration has developed new Ge detectors using the same athermal phonon sensors and ionization measurement technology of CDMS II but with larger mass, superior sensor performance and increased fabrication efficiency. The improvements in fabrication are described, a comparison of CDMS II and SuperCDMS detector production yield is reported, and future scalability addressed

    The Cryogenic Dark Matter Search (CDMS) : Present Status and Future

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    The CDMS collaboration utilizes Ge detectors for their Weakly Interacting Massive Particle (WIMP) search at the Soudan mine, Minnesota. The final data run of CDMS II is complete and a detector upgrade for SuperCDMS has commenced. A SuperTower of five 1‐inch thick Ge crystals has been installed and undergoing commissioning. Its surface‐event rejection capability should allow SuperCDMS to continue to run background free for the next proposed phases: 15 kg Ge deployment at Soudan, and up to 150 kg Ge deployment at SNOLAB. Recent detector advances to allow a 1 tonne Ge experiment are also discussed

    Bulk and Surface Charge Collection: CDMS Detector Performance and Design Implications

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    The Cryogenic Dark Matter Search (CDMS) searches for Weakly Interacting Massive Particles (WIMPs) with cryogenic germanium particle detectors. These detectors discriminate between nuclear‐recoil candidate and electron‐recoil background events by collecting both phonon and ionization energy from interactions in the crystal. Incomplete ionization collection results in the largest background in the CDMS detectors as this causes electron‐recoil background interactions to appear as false candidate events. Two primary causes of incomplete ionization collection are suface and bulk charge trapping. Recent work has been focused on reducing surface trapping through the modification of fabrication methods for future detectors. Analyzing data taken with test devices shows that hydrogen passivation of the amorphous silicon blocking layer does not reduce the effects of surface trapping. Other data shows that the iron‐ion implantation used to lower the critical temperature of the tungsten transition‐edge sensors increases surface trapping, causing a degradation of the ionization collection. Using selective implantation on future detectors may improve ionization collection for events near the phonon side detector surface. Bulk trapping is minimized by neutralizing ionized lattice impurities. Detector investigations at testing facilities and at the experimental site in Soudan, MN have provided methods to optimize the neutralization process and monitor running conditions to maintain maximal ionization collection

    Piloted Simulation Assessment of the Impact of Flexible Structures on Handling Qualities of Generic Supersonic Aircraft

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    The NASA Langley Research Center Cockpit Motion Facility (CMF) was used to conduct a piloted simulation assessment of the impact of flexible structures on flying qualities. The CMF was used because of its relatively high bandwidth, six degree-of-freedom motion capability. Previous studies assessed and attempted to mitigate the effects of multiple dynamic aeroservoelastic modes (DASE). Those results indicated problems existed, but the specific cause and effect was difficult to ascertain. The goal of this study was to identify specific DASE frequencies, damping ratios, and gains that cause degradation in handling qualities. A generic aircraft simulation was developed and designed to have Cooper-Harper Level 1 handling qualities when flown without DASE models. A test matrix of thirty-six DASE modes was implemented. The modes had frequencies ranging from 1 to 3.5 Hz and were applied to each axis independently. Each mode consisted of a single axis, frequency, damping, and gain, and was evaluated individually by six subject pilots with test pilot backgrounds. Analysis completed to date suggests that a number of the DASE models evaluated degrade the handling qualities of this class of aircraft to an uncontrollable condition

    Addressing cervical cancer disparities in Texas: Expansion of a community-based prevention initiative for medically underserved populations

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    Although cervical cancer is preventable, significant disparities exist in access to screening and prevention services. In medically underserved areas (MUAs) of Texas, these rates are 55% higher compared to the remainder of the US. In 2019, we expanded a multicomponent, comprehensive program to improve cervical cancer prevention in partnership with 13 clinics and mobile vans in MUAs of Texas. Our multicomponent intervention program consists of community education and patient navigation coupled with a training/mentoring program for local medical providers to perform diagnostic procedures and treatment for patients with abnormal screening results. Hands-on training courses to learn these skills are coupled with biweekly telementoring conferences using Project ECHOÂź (Extension for Community Healthcare Outcomes). This program was implemented in 2015 and expanded to other MUAs in Texas in 2019. From March 2019 to August 2022, 75,842 individuals were educated about cervical cancer screening and HPV vaccination. A total of 44,781 women underwent screening for cervical cancer, and 2,216 underwent colposcopy and 264 underwent LEEP. High-grade cervical dysplasia was diagnosed in 658 individuals and invasive cervical cancer in 33 individuals. We trained 22 providers to perform colposcopy and/or LEEP. In addition, 78 Project ECHO telementoring sessions were held with an average of 42 attendees per session, with 72 individual patient cases discussed. Our comprehensive community-based prevention initiative for medically underserved populations has led to a significant number of individuals undergoing cervical cancer screening in MUAs, as well as improved access to colposcopy and LEEP services

    Measuring vertebrate telomeres: applications and limitations

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    Telomeres are short tandem repeated sequences of DNA found at the ends of eukaryotic chromosomes that function in stabilizing chromosomal end integrity. In vivo studies of somatic tissue of mammals and birds have shown a correlation between telomere length and organismal age within species, and correlations between telomere shortening rate and lifespan among species. This result presents the tantalizing possibility that telomere length could be used to provide much needed information on age, ageing and survival in natural populations where longitudinal studies are lacking. Here we review methods available for measuring telomere length and discuss the potential uses and limitations of telomeres as age and ageing estimators in the fields of vertebrate ecology, evolution and conservation
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