Local Section Meetings

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Numerical simulation of film-cooled ablative rocket nozzles

The objective of this research effort was to evaluate the impact of incorporating an additional cooling port downstream between the injector and nozzle throat in the NASA Fast Track chamber. A numerical model of the chamber was developed for the analysis. The analysis did not model ablation but instead correlated the initial ablation rate with the initial nozzle wall temperature distribution. The results of this study provide guidance in the development of a potentially lighter, second generation ablative rocket nozzle which maintains desired performance levels

Civility and Academic Freedom: Who Defines the Former (and How) May Imperil Rights to the Latter

An alarming occurrence in academia involves the discipline of faculty, under the guise of violating civility or collegiality codes, for engaging in what should be protected academic free speech. This often occurs when unprincipled and/or corporate-minded administrators seek to punish or dissuade faculty from challenging or questioning their decisions or policy initiatives, or for speaking up about policy violations or lack of due process. The ambiguity of terms such as civility and collegiality, when selectively defined by administrators, can be used to stifle, dissuade or punish academic free speech. Ways to identify and address these problems are presented

Effect of lutein and antioxidant dietary supplementation on contrast sensitivity in age-related macular disease:A randomized controlled trial

Objective: The aim of the study is to determine the effect of lutein combined with vitamin and mineral supplementation on contrast sensitivity in people with age-related macular disease (ARMD). Design: A prospective, 9-month, double-masked randomized controlled trial. Setting: Aston University, Birmingham, UK and a UK optometric clinical practice. Subjects: Age-related maculopathy (ARM) and atrophic age-related macular degeneration (AMD) participants were randomized (using a random number generator) to either placebo (n = 10) or active (n=15) groups. Three of the placebo group and two of the active group dropped out. Interventions: The active group supplemented daily with 6 mg lutein combined with vitamins and minerals. The outcome measure was contrast sensitivity (CS) measured using the Pelli-Robson chart, for which the study had 80% power at the 5% significance level to detect a change of 0.3log units. Results: The CS score increased by 0.07 ± 0.07 and decreased by 0.02 ± 0.18 log units for the placebo and active groups, respectively. The difference between these values is not statistically significant (z = 0.903, P = 0.376). Conclusion: The results suggest that 6 mg of lutein supplementation in combination with other antioxidants is not beneficial for this group. Further work is required to establish optimum dosage levels

Evidence for bimodal fission in the heaviest elements

We have measured the mass and kinetic-energy partitioning in the spontaneous fission of five heavy nuclides: /sup 258/Fm, /sup 259/Md, /sup 260/Md /sup 258/No, and /sup 260/(104). Each was produced by heavy-ion reactions with either /sup 248/Cm, /sup 249/Bk, or /sup 254/Es targets. Energies of correlated fragments from the isotopes with millisecond half lives, /sup 258/No and /sup 260/(104), were measured on-line by a special rotating-wheel instrument, while the others were determined off-line after mass separation. All fissioned with mass distributions that were symmetric. Total-kinetic-energy distributions peaked near either 200 or 235 MeV. Surprisingly, because only a single Gaussian energy distribution had been observed previously in actinide fission, these energy distributions were skewed upward or downward from the peak in each case, except for /sup 260/(104), indicating a composite of two energy distributions. We were able to fit accurately two Gaussian curves to the gross energy distributions from the four remaining nuclides. From the multiple TKE distributions and the shapes of the mass distributions, we conclude that there is a low-energy fission component with liquid-drop characteristics which is admixed with a much higher-energy component due to closed fragment shells. We now have further evidence for this conclusion from measurements of the neutron multiplicity in the spontaneous fission of /sup 260/Md. 25 refs., 9 figs

An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

Polychlorinated Biphenyl Sorption and Availability in Field-Contaminated Sediments†

Traditional and new relationships of polychlorinated biphenyl (PCB) distribution among the solid phases, the free aqueous phase, and biolipids are comprehensively reviewed using seven well-characterized freshwater and marine sediments polluted with PCBs. The traditional relationship relating free aqueous concentration and biolipid concentration to sediment total organic carbon, compound octanol−water partitioning coefficient, and solid-phase contaminant concentration overestimates measured free aqueous concentrations and biolipid concentrations by mean factors of 8 and 33, respectively. By contrast, relationships based on measured free aqueous phase concentrations or the PCB mass fraction desorbed from sediment provide reasonable predictions of biolipid concentrations. Solid-phase concentration-based predictions perform better when sorption to amorphous organic matter and black carbon (BC) is distinguished. Contrary to previously published relationships, BC sorption appears to be linear for free aqueous PCB-congener concentrations in the picogram to microgram per liter range

Stigma experienced by people living with HIV who are on methadone maintenance treatment and have symptoms of common mental disorders in Hanoi, Vietnam: a qualitative study

Background: Stigma around human immunodeficiency virus (HIV), injection drug use (IDU), and mental health disorders can be co-occurring and have different impacts on the well-being of people living with HIV (PWH) who use drugs and have mental health disorders. This stigma can come from society, health professionals, and internalized stigma. A person who has more than one health condition can experience overlapping health-related stigma and levels of stigma which can prevent them from receiving necessary support and healthcare, serving to intensify their experience with stigma. This study investigates HIV, drug use, and mental health stigmas in three dimensions (social, internalized, and professional) around PWH on methadone maintenance treatment (MMT) who have common mental disorders (CMDs) including depression, anxiety, and stress-related disorders in Hanoi, Vietnam.Please check and confirm whether corresponding author's email id is correctly identified.The cooresponding author's email is correct Methods: We conducted semi-structured, in-depth interviews (IDIs) (n = 21) and two focus group discussions (FGDs) (n = 10) with PWH receiving MMT who have CMD symptoms, their family members, clinic health care providers, and clinic directors. We applied thematic analysis using NVIVO software version 12.0, with themes based on IDI and FGD guides and emergent themes from interview transcripts. Results: The study found evidence of different stigmas towards HIV, IDU, and CMDs from the community, family, health care providers, and participants themselves. Community and family members were physically and emotionally distant from patients due to societal stigma around illicit drug use and fears of acquiring HIV. Participants often conflated stigmas around drug use and HIV, referring to these stigmas interchangeably. The internalized stigma around having HIV and injecting drugs made PWH on MMT hesitant to seek support for CMDs. These stigmas compounded to negatively impact participants’ health. Conclusions: Strategies to reduce stigma affecting PWH on MMT should concurrently address stigmas around HIV, drug addiction, and mental health. Future studies could explore approaches to address internalized stigma to improve self-esteem, mental health, and capacities to cope with stigma for PWH on MMT. Trial registration: NCT04790201, available at clinicaltrials.gov

New Fragment Separation Technology for Superheavy Element Research

This project consisted of three major research areas: (1) development of a solid Pu ceramic target for the MASHA separator, (2) chemical separation of nuclear decay products, and (3) production of new isotopes and elements through nuclear reactions. There have been 16 publications as a result of this project, and this collection of papers summarizes our accomplishments in each of the three areas of research listed above. The MASHA (Mass Analyzer for Super-Heavy Atoms) separator is being constructed at the U400 Cyclotron at the Flerov Laboratory of Nuclear Reactions in Dubna, Russia. The purpose of the separator is to physically separate the products from nuclear reactions based on their isotopic masses rather than their decay characteristics. The separator was designed to have a separation between isotopic masses of {+-}0.25 amu, which would enable the mass of element 114 isotopes to be measured with outstanding resolution, thereby confirming their discovery. In order to increase the production rate of element 114 nuclides produced via the {sup 244}Pu+{sup 48}Ca reaction, a new target technology was required. Instead of a traditional thin actinide target, the MASHA separator required a thick, ceramic-based Pu target that was thick enough to increase element 114 production while still being porous enough to allow reaction products to migrate out of the target and travel through the separator to the detector array located at the back end. In collaboration with UNLV, we began work on development of the Pu target for MASHA. Using waste-form synthesis technology, we began by creating zirconia-based matrices that would form a ceramic with plutonium oxide. We used samarium oxide as a surrogate for Pu and created ceramics that had varying amounts of the starting materials in order to establish trends in material density and porosity. The results from this work are described in more detail in Refs. [1,4,10]. Unfortunately, work on MASHA was delayed in Russia because it was found that the efficiency of transporting products from the target chamber to the detector array was much too low for applications in heavy element experiments where production rates are on the order of one atom per day or less. Work continues on the MASHA separator, and once the efficiency has been improved, we plan to continue our work on the Pu target for future element 114 experiments. Due to the delays of the MASHA separator, work on establishing the identity of heavy element species produced through nuclear reactions focused instead on chemical separations. In particular, element 115 decays through a series of alpha decays, terminating with an element 105 isotope with a long half-life ({approx} 1 day). By chemically separating the element 105 daughter and observing its subsequent fission decay, the identity of the original parent nucleus can be established through the genetic correlation of the initial series of alpha decays. Chemical separations of element 105 were developed in Switzerland, Russia, and at LLNL. Over the course of two experiments, reaction products from the {sup 243}Am+{sup 48}Ca reaction were collected in a copper block and subsequently processed for chemical separation of the Group Five elements [8,9,13,15]. The Group Five elements were initially separated from the Group Four species, and then the samples were sub-divided into tantalum and niobium fractions. All of the fission events were observed in the tantalum fractions, which implied that element 105 behaved more like tantalum under the chemical conditions of these experiments. These experiments were very successful, and not only demonstrated that chemical separation could be performed on single atoms of interest, but also lent proof to the identity of the parent nucleus as element 115. Subsequent analysis of the alpha spectra taken during the experiment further prove that the fission events observed during the two experiments came from element 105 as the decay daughter of element 115 and could not attributed to interference from other background species [16]. The final aspect of this project was the production of new isotopes and elements. All of the experiments were performed in Dubna at the U400 Cyclotron and the results are described in more detail in Refs. [2,3,5-8,11,12,14]. The first experiments were designed to establish the decay properties of isotopes of elements 112, 114, and 116 [5]. Because these isotopic signatures were established through these initial experiments, the discovery of element 118 [11] was possible, since the 118 nuclides decayed into these previously studied isotopes. This was the first successful report of the discovery of element 118, which was reported by the media to a large extent. The last experiment that was performed for this project was the production and detection of a new isotope of element 113 [14]