Quantitative determination of tritium in metals and oxides

Metallic samples are analyzed for tritium by heating the sample at 1225 K in a moist oxygen stream. The volatile products are trapped and the tritium is quantitatively determined by scintillation spectroscopy. The method is used to determine less than 1 ppb of tritium in 100-mg samples of lithium, iron, nickel, cerium, plutonium, and plutonium dioxide. Analysis of 18 cuts of a tritium-zirconium, copper foil standard over a 3-yr period showed a tritium content of 45 ppM and a standard deviation of 6 ppM

Longitudinal relationships between subjective fatigue, cognitive function, and everyday functioning in old age

Background: The present study examined the prospective relationships between subjective fatigue, cognitive function, and everyday functioning. Methods: A cohort study with secondary data analysis was conducted using data from 2,781 community-dwelling older adults without dementia who were enrolled to participate in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) randomized intervention trial. Measures included demographic and health information at baseline, and annual assessments of subjective fatigue, cognitive function (i.e. speed of processing, memory, and reasoning), and everyday functioning (i.e. everyday speed and everyday problem-solving) over five years. Results: Four distinct classes of subjective fatigue were identified using growth mixture modeling: one group complaining fatigue some of the time at baseline but most of the time at five-year follow-up (increased fatigue), one complaining fatigue a good bit of the time constantly over time (persistent fatigue), one complaining fatigue most of the time at baseline but some of the time at five-year follow-up (decreased fatigue), and the fourth complaining fatigue some of the time constantly over time (persistent energy). All domains of cognitive function and everyday functioning declined significantly over five years; and the decline rates, but not the baseline levels, differed by the latent class of subjective fatigue. Except for the decreased fatigue class, there were different degrees of significant associations between the decline rates of subjective fatigue and all domains of cognitive function and everyday functioning in other classes of subjective fatigue. Conclusion: Future interventions should address subjective fatigue when managing cognitive and functional abilities in community-dwelling older adults

Prevalence and Correlates of Self-Rated Successful Aging Among Older Women Living With HIV

BACKGROUND: Despite marked gains in longevity attributable to antiretroviral therapy (ART), older women living with HIV (OWLH) experience substantial health challenges, and few studies addressed whether they can achieve successful aging (SA). This is among the first studies examining prevalence and psychosocial correlates of self-rated SA (SRSA) among OWLH and women at risk of HIV. METHODS: The sample included 386 OWLH and 137 HIV-seronegative women enrolled in the Women's Interagency HIV Study (WIHS) who were aged 50 years and older and participated in the "From Surviving to Thriving" (FROST) substudy. The FROST survey included measures of SRSA and positive psychosocial constructs. RESULTS: Participants were on average 57 years (SD = 5.3), 74% African American and 30% unemployed. Among OWLH, 94% were on ART and 73% were virally suppressed. Compared with OWLH, a higher proportion of HIV-seronegative women had an annual income ≤ $6000, no health insurance, and reported lower optimism and health-related quality of life. We found no differences in SRSA prevalence by HIV status: 84% of OWLH and 83% of HIV-seronegative women reported SRSA ≥7 (range = 2-10, higher scores signify better SRSA). Having SRSA ≥7 was associated with higher levels of positive psychosocial characteristics (eg, resilience and optimism) among both OWLH and HIV-seronegative women. CONCLUSIONS: SRSA is achievable among older women with and at risk of HIV despite health complications. Among disadvantaged women, factors other than HIV may be primary drivers of SRSA. Future research is needed to examine determinants of SRSA and to design public health interventions enhancing SA within this population

The effect of finite-range interactions in classical transport theory

The effect of scattering with non-zero impact parameters between consituents in relativistic heavy ion collisions is investigated. In solving the relativistic Boltzmann equation, the characteristic range of the collision kernel is varied from approximately one fm to zero while leaving the mean-free path unchanged. Modifying this range is shown to significantly affect spectra and flow observables. The finite range is shown to provide effective viscosities, shear, bulk viscosity and heat conductivity, with the viscous coefficients being proportional to the square of the interaction range

Psychosocial Mechanisms of Self-rated Successful Aging with HIV: A Structural Equation Model

This study tested a conceptual psychosocial model of self-rated successful aging (SRSA) with HIV. Our sample (n = 356) included older women living with HIV (OWLH): average age 56.5 years, 73% Black. SRSA was assessed using a research-based 10-point scale (higher scores = better outcomes). We conducted adjusted structural equation modeling. The global model included two latent variables—protective attributes (composite of positive psychosocial factors: resilience, personal mastery, optimism, spirituality) and psychological distress (composite of negative psychosocial factors: anxiety, depression, loneliness, internalized HIV-related stigma). The model showed good fit (χ2(58) = 76, p = 0.06; RMSEA = 0.03; CFI = 0.99). Increased protective attributes were associated with improved SRSA both directly and mediated by improved coping with stress. While psychological distress did not have a direct effect on SRSA, it was indirectly associated with worsened SRSA via diminished protective attributes and via decreased coping with stress. Findings suggest the need for interventions enhancing positive and mitigating negative psychosocial factors in OWLH

Class-Based Antiretroviral Exposure and Cognition Among Women Living with HIV

Neurologic complications of the human immunodeficiency virus (HIV) are common in treated individuals, and toxicity of certain antiretroviral therapies (ART) may contribute to cognitive impairment. We investigated exposures to specific ART and cognition among women living with HIV (WLWH). Virologically suppressed (viral load <200 copies/mL during at least two semi-annual visits) WLWH and age/race matched HIV-seronegative controls enrolled in the Women's Interagency HIV Study who completed at least two biennial cognitive assessments were included. Analysis of WLWH was restricted to those with exposure to the drug class of interest and a nucleoside reverse transcriptase inhibitor (NRTI) backbone. Generalized estimating equations were used to evaluate repeated measures of cognition over time in association with ART class exposure. Among 1,242 eligible WLWH, 20% (n = 247) had isolated drug exposure to non-nucleoside reverse transcriptase inhibitors (NNRTI), 18% (n = 219) to protease inhibitors (PIs), and 6% (n = 79) to integrase inhibitors with a NRTI backbone. Cognitive assessments were performed at a median of 3 biennial visits {IQR 2-4 visits}. At the index assessment, 21% of WLWH demonstrated global cognitive impairment versus 29% at their last cognitive assessment. In multivariable analyses adjusted for hypertension, depression, diabetes mellitus, history of AIDS-defining illness, alcohol use, number of medications, and time on ART, WLWH exposed to NNRTIs demonstrated verbal learning improvements (mean T-score change 1.3, p = .020) compared to other treated women. Compared to HIV-seronegative women, WLWH exposed to PIs had worse verbal learning (mean T-score difference -2.62, p = .002) and verbal memory performance (mean T-score difference -1.74, p = .032) at baseline. Compared to HIV-seronegative women, WLWH exposed to PIs had improvements in verbal learning (mean T-score slope difference 0.36, p = .025) and verbal memory (mean T-score slope difference 0.32, p = .042). The index T-score and slope of change in the T-score were similar among other treated groups and the HIV-seronegative group. We noted emerging trends in cognition in WLWH exposed to specific drug classes. Ongoing study of this relatively young group is important to characterize long-term cognitive outcomes and effect of antiretrovirals as treatment guidelines evolve

Factors Predicting Detrimental Change in Declarative Memory Among Women With HIV: A Study of Heterogeneity in Cognition

Objective: Statistical techniques used to study cognitive function in HIV typically yield normative estimates and can mask the heterogeneity in cognitive trajectories over time. We applied a novel statistical approach to identify clusters of individuals with distinct patterns of change in declarative memory in HIV-seropositive (HIV+) and HIV-seronegative (HIV−) women. Methods: 1731 women from the Women’s Interagency HIV Study, a multi-center, prospective cohort study, completed the Hopkins Verbal Learning Test-Revised (HLVT-R) at >2 visits. To derive subgroups with similar patterns of decline by HIV-serostatus, we used a mixed-effects framework that modeled the trajectory of multiple declarative memory outcomes over time, while simultaneously clustering individuals. Results: Of the 1731 participants, 1149 were HIV+ (70% Black/African American [AA]; 30% White/Other [W/O]) and 582 were HIV− (68% AA; 32% W/O). Race stratification was necessary to optimize clustering. Among HIV+AA’s, four subgroups emerged: a subgroup with minimal decline, two with accelerated decline, and one with stable but low performance. In HIV− AA, three subgroups emerged: one with minimal decline and two with accelerated decline. In multivariable-adjusted models among HIV+, individuals with accelerated decline were less educated (P < 0.001) and more likely to have a history of depression (P < 0.001) versus those with minimal decline. Similar subgroups were identified in W/O HIV+ and W/O HIV− participants. Conclusion: We identified clinically meaningful subgroups of women with distinct phenotypes of declarative memory decline, which depend on race and HIV-serostatus using a data driven approach. Identification of underlying mechanisms and risk factors contributing to the observed differences are warranted. More broadly our modeling approach could be other populations to identify risk factors for accelerated cognitive decline and to personalize interventions

Socioeconomic, Psychosocial, and Clinical Factors Associated with Employment in Women with HIV in the United States: A Correlational Study

Employment is a social determinant of health, and women living with HIV (WLWH) are often underemployed. This correlational study examined the socioeconomic, psychosocial, and clinical factors associated with employment among WLWH (n = 1,357) and women at risk for HIV (n = 560). Descriptive and inferential statistics were used to evaluate factors associated with employment status. Employment was associated (p ≤.05) with better socioeconomic status and quality of life (QOL), less tobacco and substance use, and better physical, psychological, and cognitive health. Among WLWH, employment was associated (p ≤.05) with improved adherence to HIV care visits and HIV RNA viral suppression. Using multivariable regression modeling, differences were found between WLWH and women at risk for HIV. Among WLWH, household income, QOL, education, and time providing childcare remained associated with employment in adjusted multivariable analyses (R2=.272, p &lt;.001). A better understanding of the psychosocial and structural factors affecting employment is needed to reduce occupational disparities among WLWH

Patterns and Predictors of Cognitive Function Among Virally Suppressed Women With HIV

Cognitive impairment remains frequent and heterogeneous in presentation and severity among virally suppressed (VS) women with HIV (WWH). We identified cognitive profiles among 929 VS-WWH and 717 HIV-uninfected women from 11 Women's Interagency HIV Study sites at their first neuropsychological (NP) test battery completion comprised of: Hopkins Verbal Learning Test-Revised, Trail Making, Symbol Digit Modalities, Grooved Pegboard, Stroop, Letter/Animal Fluency, and Letter-Number Sequencing. Using 17 NP performance metrics (T-scores), we used Kohonen self-organizing maps to identify patterns of high-dimensional data by mapping participants to similar nodes based on T-scores and clustering those nodes. Among VS-WWH, nine clusters were identified (entropy = 0.990) with four having average T-scores ≥45 for all metrics and thus combined into an “unimpaired” profile (n = 311). Impaired profiles consisted of weaknesses in: (1) sequencing (Profile-1; n = 129), (2) speed (Profile-2; n = 144), (3) learning + recognition (Profile-3; n = 137), (4) learning + memory (Profile-4; n = 86), and (5) learning + processing speed + attention + executive function (Profile-5; n = 122). Sociodemographic, behavioral, and clinical variables differentiated profile membership using Random Forest models. The top 10 variables distinguishing the combined impaired vs. unimpaired profiles were: clinic site, age, education, race, illicit substance use, current and nadir CD4 count, duration of effective antiretrovirals, and protease inhibitor use. Additional variables differentiating each impaired from unimpaired profile included: depression, stress-symptoms, income (Profile-1); depression, employment (Profile 2); depression, integrase inhibitor (INSTI) use (Profile-3); employment, INSTI use, income, atazanavir use, non-ART medications with anticholinergic properties (Profile-4); and marijuana use (Profile-5). Findings highlight consideration of NP profile heterogeneity and potential modifiable factors contributing to impaired profiles