O2 partitioning of sulfur oxidizing bacteria drives acidity and thiosulfate distributions in mining waters.

The acidification of water in mining areas is a global environmental issue primarily catalyzed by sulfur-oxidizing bacteria (SOB). Little is known about microbial sulfur cycling in circumneutral pH mine tailing impoundment waters. Here we investigate biological sulfur oxidation over four years in a mine tailings impoundment water cap, integrating aqueous sulfur geochemistry, genome-resolved metagenomics and metatranscriptomics. The microbial community is consistently dominated by neutrophilic, chemolithoautotrophic SOB (relative abundances of ~76% in 2015, ~55% in 2016/2017 and ~60% in 2018). Results reveal two SOB strategies alternately dominate across the four years, influencing acid generation and sulfur speciation. Under oxic conditions, novel Halothiobacillus drive lower pH conditions (as low as 4.3) and lower [S2O32-] via the complete Sox pathway coupled to O2. Under anoxic conditions, Thiobacillus spp. dominate in activity, via the incomplete Sox and rDSR pathways coupled to NO3-, resulting in higher [S2O32-] and no net significant acidity generation. This study provides genomic evidence explaining acidity generation and thiosulfate accumulation patterns in a circumneutral mine tailing impoundment and has significant environmental applications in preventing the discharge of sulfur compounds that can impact downstream environments. These insights illuminate opportunities for in situ biotreatment of reduced sulfur compounds and prediction of acidification events using gene-based monitoring and in situ RNA detection.

Examining the Association of Food Insecurity and Being Up-to-Date for Breast and Colorectal Cancer Screenings.

BACKGROUND: Food insecurity (FI) has been associated with poor access to health care. It is unclear whether this association is beyond that predicted by income, education, and health insurance. FI may serve as a target for intervention given the many programs designed to ameliorate FI. We examined the association of FI with being up-to-date to colorectal cancer and breast cancer screening guidelines. METHODS: Nine NCI-designated cancer centers surveyed adults in their catchment areas using demographic items and a two-item FI questionnaire. For the colorectal cancer screening sample (n = 4,816), adults ages 50-75 years who reported having a stool test in the past year or a colonoscopy in the past 10 years were considered up-to-date. For the breast cancer screening sample (n = 2,449), female participants ages 50-74 years who reported having a mammogram in the past 2 years were up-to-date. We used logistic regression to examine the association between colorectal cancer or breast cancer screening status and FI, adjusting for race/ethnicity, income, education, health insurance, and other sociodemographic covariates. RESULTS: The prevalence of FI was 18.2% and 21.6% among colorectal cancer and breast cancer screening participants, respectively. For screenings, 25.6% of colorectal cancer and 34.1% of breast cancer participants were not up-to-date. In two separate adjusted models, FI was significantly associated with lower odds of being up-to-date with colorectal cancer screening [OR, 0.7; 95% confidence interval (CI), 0.5-0.99)] and breast cancer screening (OR, 0.6; 95% CI, 0.4-0.96). CONCLUSIONS: FI was inversely associated with being up-to-date for colorectal cancer and breast cancer screening. IMPACT: Future studies should combine FI and cancer screening interventions to improve screening rates.

Injustice Appraisal, but not Pain Catastrophizing, Mediates the Relationship Between Perceived Ethnic Discrimination and Depression and Disability in Low Back Pain.

Despite growing evidence of significant racial disparities in the experience and treatment of chronic pain, the mechanisms by which these disparities manifest have remained relatively understudied. The current study examined the relationship between past experiences of racial discrimination and pain-related outcomes (self-rated disability and depressive symptomatology) and tested the potential mediating roles of pain catastrophizing and perceived injustice related to pain. Analyses consisted of cross-sectional path modeling in a multiracial sample of 137 individuals with chronic low back pain (Hispanics: n = 43; blacks: n = 43; whites: n = 51). Results indicated a positive relationship between prior discriminatory experiences and severity of disability and depressive symptoms. In mediation analyses, pain-related appraisals of injustice, but not pain catastrophizing, were found to mediate these relationships. Notably, the association between discrimination history and perceived injustice was significantly stronger in black and Hispanic participants and was not statistically significant in white participants. The findings suggest that race-based discriminatory experiences may contribute to racial disparities in pain outcomes and highlight the specificity of pain-related, injustice-related appraisals as a mechanism by which these experiences may impair physical and psychosocial function. Future research is needed to investigate temporal and causal mechanisms suggested by the model through longitudinal and clinical intervention studies. PERSPECTIVE: More frequent prior experiences of racial discrimination are associated with greater depressive symptomatology and pain-related disability in individuals with chronic low back pain. These associations are explained by the degree of injustice perception related to pain, but not pain catastrophizing, and were stronger among black and Hispanic participants.

Weighting Nonprobability and Probability Sample Surveys in Describing Cancer Catchment Areas.

BACKGROUND: The Population Health Assessment initiative by NCI sought to enhance cancer centers' capacity to acquire, aggregate, and integrate data from multiple sources, as well as to plan, coordinate, and enhance catchment area analysis activities. METHODS: Key objectives of this initiative are pooling data and comparing local data with national data. A novel aspect of analyzing data from this initiative is the methodology used to weight datasets from sites that collected both probability and nonprobability samples. This article describes the methods developed to weight data, which cancer centers collected with combinations of probability, and nonprobability sampling designs. RESULTS: We compare alternative weighting methods in particular for the hybrid probability and nonprobability sampling designs employed by different cancer centers. We also include comparisons of local center data with national survey data from large probability samples. CONCLUSIONS: This hybrid approach to calculating statistical weights can be implemented both within cancer centers that collect both probability and nonprobability samples with common measures. Aggregation can also apply to cancer centers that share common data elements, and target similar populations, but differ in survey sampling designs. IMPACT: Researchers interested in local versus national comparisons for cancer surveillance and control outcomes should consider various weighting approaches, including hybrid approaches, when analyzing their data.

Satisfaction With Work-Family Balance Mediates the Relationship Between Workplace Social Support and Depression Among Hospice Nurses.

PURPOSE: The purpose of this study was to investigate the relationship between social support (from personal and workplace sources) and psychological distress (depression, anxiety, and stress symptoms), as well as to examine the mediating role of satisfaction with work-family balance among hospice nurses. DESIGN AND METHOD: A cross-sectional study design was utilized with a sample of 90 hospice nurses from the southern United States. Participants completed online surveys, including (a) the Depression, Anxiety, and Stress Scale (DASS-21), (b) loosely adapted items from the Affectivity, Burnout, and Absenteeism Scales, and (c) Satisfaction with Work-Family Balance Scale. FINDINGS: Workplace social support, not personal social support, was associated with lower psychological distress, and satisfaction with work-family balance mediated the relationship between workplace social support and depression symptoms, a component of psychological distress. CONCLUSIONS: Hospice nurses' social support in the workplace and their satisfaction with the balance between their work and family lives play a role in supporting their mental health. CLINICAL RELEVANCE: Hospice nurses may benefit from programs fostering the creation of workplace-based interpersonal relationships.

VALIDATION OF ULTRASOUND AS A NONINVASIVE TOOL TO MEASURE SUBCUTANEOUS FAT DEPTH IN LEATHERBACK SEA TURTLES (DERMOCHELYS CORIACEA).

Leatherback turtles (Dermochelys coriacea) undergo substantial cyclical changes in body condition between foraging and nesting. Ultrasonography has been used to measure subcutaneous fat as an indicator of body condition in many species but has not been applied in sea turtles. To validate this technique in leatherback turtles, ultrasound images were obtained from 36 live-captured and dead-stranded immature and adult turtles from foraging and nesting areas in the Pacific and Atlantic oceans. Ultrasound measurements were compared with direct measurements from surgical biopsy or necropsy. Tissue architecture was confirmed histologically in a subset of turtles. The dorsal shoulder region provided the best site for differentiation of tissues. Maximum fat depth values with the front flipper in a neutral (45-90°) position demonstrated good correlation with direct measurements. Ultrasound-derived fat measurements may be used in the future for quantitative assessment of body condition as an index of health in this critically endangered species.

Assessing microbial competition in a hydrogen-based membrane biofilm reactor (MBfR) using multidimensional modeling.

The membrane biofilm reactor (MBfR) is a novel technology that safely delivers hydrogen to the base of a denitrifying biofilm via gas-supplying membranes. While hydrogen is an effective electron donor for denitrifying bacteria (DNB), it also supports sulfate-reducing bacteria (SRB) and methanogens (MET), which consume hydrogen and create undesirable by-products. SRB and MET are only competitive for hydrogen when local nitrate concentrations are low, therefore SRB and MET primarily grow near the base of the biofilm. In an MBfR, hydrogen concentrations are greatest at the base of the biofilm, making SRB and MET more likely to proliferate in an MBfR system than a conventional biofilm reactor. Modeling results showed that because of this, control of the hydrogen concentration via the intramembrane pressure was a key tool for limiting SRB and MET development. Another means is biofilm management, which supported both sloughing and erosive detachment. For the conditions simulated, maintaining thinner biofilms promoted higher denitrification fluxes and limited the presence of SRB and MET. The 2-d modeling showed that periodic biofilm sloughing helped control slow-growing SRB and MET. Moreover, the rough (non-flat) membrane assembly in the 2-d model provided a special niche for SRB and MET that was not represented in the 1-d model. This study compared 1-d and 2-d biofilm model applicability for simulating competition in counter-diffusional biofilms. Although more computationally expensive, the 2-d model captured important mechanisms unseen in the 1-d model.

Multidimensional modeling of biofilm development and fluid dynamics in a hydrogen-based, membrane biofilm reactor (MBfR).

A two-dimensional, particle-based biofilm model coupled with mass transport and computational fluid dynamics was developed to simulate autotrophic denitrification in a spiral-wound membrane biofilm reactor (MBfR), where hydrogen is supplied via hollow-fiber membrane fabric. The spiral-wound configuration consists of alternating layers of plastic spacer net and membrane fabric that create rows of flow channels, with the top and bottom walls comprised of membranes. The transversal filaments of the spacer partially obstruct the channel flow, producing complex mixing and shear patterns that require multidimensional representation. This study investigated the effect of hydrogen and nitrate concentrations, as well as spacer configuration, on biofilm development and denitrification fluxes. The model results indicate that the cavity spacer filaments, which rest on the bottom membranes, cause uneven biofilm growth. Most biofilm resided on the bottom membranes, only in the wake of the filaments where low shear zones formed. In this way, filament configuration may help achieve a desired biofilm thickness. For the conditions tested in this study, the highest nitrate fluxes were attained by minimizing the filament diameter and maximizing the filament spacing. This lowered the shear stress at the top membranes, allowing for more biofilm growth. For the scenarios studied, biomass limitation at the top membranes hindered performance more significantly than diffusion limitation in the thick biofilms at the bottom membranes. The results also highlighted the importance of two-dimensional modeling to capture uneven biofilm growth on a substratum with geometrical complexity.

Underwater hearing in the loggerhead turtle (Caretta caretta): a comparison of behavioral and auditory evoked potential audiograms.

The purpose of this study was to compare underwater behavioral and auditory evoked potential (AEP) audiograms in a single captive adult loggerhead sea turtle (Caretta caretta). The behavioral audiogram was collected using a go/no-go response procedure and a modified staircase method of threshold determination. AEP thresholds were measured using subdermal electrodes placed beneath the frontoparietal scale, dorsal to the midbrain. Both methods showed the loggerhead sea turtle to have low frequency hearing with best sensitivity between 100 and 400 Hz. AEP testing yielded thresholds from 100 to 1131 Hz with best sensitivity at 200 and 400 Hz (110 dB re. 1 µPa). Behavioral testing using 2 s tonal stimuli yielded underwater thresholds from 50 to 800 Hz with best sensitivity at 100 Hz (98 dB re. 1 µPa). Behavioral thresholds averaged 8 dB lower than AEP thresholds from 100 to 400 Hz and 5 dB higher at 800 Hz. The results suggest that AEP testing can be a good alternative to measuring a behavioral audiogram with wild or untrained marine turtles and when time is a crucial factor.

The membrane biofilm reactor (MBfR) for water and wastewater treatment: principles, applications, and recent developments.

The membrane biofilm reactor (MBfR), an emerging technology for water and wastewater treatment, is based on pressurized membranes that supply a gaseous substrate to a biofilm formed on the membrane's exterior. MBfR biofilms behave differently from conventional biofilms due to the counter-diffusion of substrates. MBfRs are uniquely suited for numerous treatment applications, including the removal of carbon and nitrogen when oxygen is supplied, and reduction of oxidized contaminants when hydrogen is supplied. Major benefits include high gas utilization efficiency, low energy consumption, and small reactor footprints. The first commercial MBfR was recently released, and its success may lead to the scale-up of other applications. MBfR development still faces challenges, including biofilm management, the design of scalable reactor configurations, and the identification of cost-effective membranes. If future research and development continue to address these issues, the MBfR may play a key role in the next generation of sustainable treatment systems.