Gradual degradation in InAs quantum dot lasers on Si and GaAs.

Reliable quantum dot lasers on silicon are a key remaining challenge to successful integrated silicon photonics. In this work, quantum dot (QD) lasers on silicon with and without misfit dislocation trapping layers are aged for 12 000 hours and are compared to QD lasers on native GaAs aged for 8400 hours. The non-trapping-layer (TL) laser on silicon degrades heavily during this time, but much more modest gradual degradation is observed for the other two devices. Electroluminescence imaging reveals relatively uniform gradual dimming for the aged TL laser on silicon. At the same time, we find nanoscale dislocation loop defects throughout the quantum dot-based active region of all three aged lasers via electron microscopy. The Burgers vector of these loops is consistent with . We suggest that the primary source of degradation, however, is the generation and migration of point defects that substantially enhance non-radiative recombination in the active region, the visible symptom of which is the formation of dislocation loops. To prevent this, we propose that laser fabrication should be switched from deeply etched to shallow etch ridges where the active region remains intact near the mesa. Additionally, post-growth annealing and altered growth conditions in the active region should be explored to minimize the grown-in point defect density.

Exposure to Perfluoroalkyl Substances and Associations with Pubertal Onset and Serum Reproductive Hormones in a Longitudinal Study of Young Girls in Greater Cincinnati and the San Francisco Bay Area.

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS), endocrine disrupting chemicals with worldwide exposure, cause changes in mammary gland development in rodents. A few human studies report delay in pubertal events with increasing perfluorooctanoic acid (PFOA) exposure, but to our knowledge none have examined reproductive hormone levels at thelarche. METHODS: In a cohort of Greater Cincinnati (GC) and San Francisco Bay Area (SFBA) girls recruited at 6-8 years of age, clinical examinations were conducted annually or semiannually with sequential Tanner staging. PFAS concentrations were measured in the first serum sample of 704 girls. In 304 GC girls, estradiol (E2), estrone (E1), testosterone (T), and dihydroepiandrosterone sulfate (DHEAS) were measured in serum at four time points around puberty. Relationships between PFAS and age at thelarche, pubarche, and menarche were analyzed using survival and structural equation models. The association between PFAS and reproductive hormones was assessed using linear regression models. RESULTS: Median PFOA serum concentrations in GC (N=353, 7.3 ng/mL) and the SFBA (N=351, 5.8 ng/mL) were higher than in the U.S. POPULATION: In multivariable Cox proportional hazard models [adjusted for race, body mass index (BMI)], increasing serum log-transformed PFOA was associated with a delay in pubarche [hazard ratio (HR)=0.83; 95% CI: 0.70, 0.99] and menarche (HR=0.04; 95% CI: 0.01, 0.25). Structural equation models indicated a triangular relationship between PFOA, BMI percentile, and the age at the pubertal milestone. Increased PFOA had a statistically significant direct effect of delay on all three milestones, as did BMI. Perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDeA), and 2-(N-methyl-perfluorooctane sulfonamido) acetic acid (Me-PFOSA-AcOH) also were associated with later thelarche, and Me-PFOSA-AcOH also with later pubarche. PFOA was inversely associated with DHEAS (p<0.01), E1 (p=0.04), and T (p=0.03) concentrations at 6 months prior to puberty. CONCLUSIONS: PFAS may delay pubertal onset through the intervening effects on BMI and reproductive hormones. The decreases in DHEAS and E1 associated with PFOA represent biological biomarkers of effect consistent with the delay in onset of puberty. https://doi.org/10.1289/EHP11811.

Surface changes observed on a Venusian volcano during the Magellan mission.

Venus has a geologically young surface, but it is unknown whether it has ongoing active volcanism. From 1990 to 1992, the Magellan spacecraft imaged the planet's surface, using synthetic aperture radar. We examined volcanic areas on Venus that were imaged two or three times by Magellan and identified an ~2.2-square-kilometer volcanic vent that changed shape in the 8-month interval between two radar images. Additional volcanic flows downhill from the vent are visible in the second-epoch images, although we cannot rule out that they were present but invisible in the first epoch because of differences in imaging geometry. We interpret these results as evidence of ongoing volcanic activity on Venus.

Metals dust in workers' homes and potential for take home in the Greater Boston area: Pilot study.

Toxic metals such as lead, cadmium, arsenic, are present at construction worksites. From work, metals can easily, unintentionally be transported to homes of workers, contaminating living spaces and affecting others including children, known as "take-home exposure." Focus has been given to minimizing lead take-home exposure but less is known about other metals. This pilot study aims to better understand the sources and predictors of metals in the home primarily of construction workers (n = 21), but also explore other workers potentially exposed [janitorial (n = 4) and auto repair (n = 2) jobs]. Greater Boston workers were recruited in 2018-2019 through collaboration with community-based organizations and worker unions serving low-income/immigrant workers. During a home visit, a dust vacuum sample was collected, a worker questionnaire was administered, and home observations were performed to determine factors that could affect home metals concentration. Thirty elements were analyzed in the dust via inductively coupled plasma coupled to atomic emission and mass spectrometry. We performed univariable and multivariable models, potential predictive factors, and multivariable mixed-effect regression analyses combining metals. Arsenic, chromium, copper, lead, manganese, nickel, and tin, commonly found in construction, were higher in construction workers' home dust compared to other workers, although not statistically significant. Sociodemographic/work/home-related variables affected home metals dust concentrations. Various work-related factors were associated with higher metal dust levels, for example: no work locker vs. locker (nickel ratio of means or ROM = 4.2, p < 0.05); mixing vs. no mixing work/personal items (nickel ROM = 1.6, p < 0.05); dusty vs. no dusty at work (copper ROM = 3.1, p < 0.05); not washing vs. washing hands after work (manganese ROM = 1.4, p < 0.05); not changing vs. changing clothes after work (cadmium ROM = 6.9, p < 0.05; copper ROM = 3.6, p < 0.05). Mixed effect regression confirmed statistical significance, which suggests a likelihood of metal mixtures carrying a "take-home" potential. Lead home interventions should evaluate other metals exposure reduction.

Expanding Reach of Occupational Health Knowledge: Contributing Subject-Matter Expertise to Wikipedia as a Class Assignment.

The National Institute for Occupational Safety and Health (NIOSH) and several university programs have collaborated on a large effort to expand and improve occupational safety and health content in Wikipedia using a platform developed by Wiki Education. This article describes the initiative, student contributions, and evaluations of this effort by instructors from two universities between 2016 and 2020. The Wiki Education platform allowed instructors to set timelines and track students' progress throughout the semester while students accessed training to best expand health content in Wikipedia. Students chose topics in occupational health based on their interests and by a set of topics deemed as a priority by the "WikiProject Occupational Safety and Health." Students' contributions were peer-reviewed by instructors, NIOSH Wikipedians-in-Residence, and traditional Wikipedians. Students presented their projects in class at the end of the semester. Students from both schools expanded 55 articles, created 8 new articles, and translated 2 articles to Spanish, adding 1270 references; these articles were viewed over 8 million times by May 2020. Feedback received from the implementation suggested that students learned about science communication and digital literacy-providing valuable content on occupational health while reducing misinformation in the public domain. The process of identifying and addressing gaps in occupational health in Wikipedia requires participation and engagement toward improving access to information that otherwise would be restricted to the scientific literature, often behind a paywall. The Wikipedia assignment proved to be an engaging approach for instruction and information literacy. It helped students improve their science communication skills and digital literacy, tools that are likely to be critical for successful communication of science in their future careers.

Factors affecting lead dust in construction workers' homes in the Greater Boston Area.

Lead is a known reproductive, developmental, and neurological toxicant. Workers with a high likelihood of being exposed to lead at work may inadvertently transport lead home from work, known as "take-home exposure." This is concerning for many workers for whom a workplace intervention is not feasible because their worksites and employers often change, rendering centralized strategies insufficient. This study aimed to better understand the connection between lead in the home of workers living with children and work in construction (n = 23), while other occupations were used as a comparison group (janitorial n = 5, autobody n = 2). Thirty workers living in disadvantaged communities in the Greater Boston area were recruited in 2018-2019 through collaboration with non-profits and worker unions with expertise working with low-income or immigrant workers. Construction workers that performed renovations, bridge constructions, welding, metal work, and demolitions were prioritized during recruitment. During a visit to their residences, a worker questionnaire was administered, and observations and a dust vacuumed sample of the home were collected. Factors predicting lead in home dust were explored by a bivariate analysis and a multivariable regression model. We found lead in homes' dust in the range of 20-8,310 ppm. Homes of construction workers generally had higher and more variable lead dust concentrations (mean 775, max 8,300 ppm) than autobody and janitor worker homes combined (mean 296, max 579 ppm). Five of the construction workers' home lead dust concentrations exceeded US guidelines for yard soil in children's play areas of 400 ppm, and were similar to other studies of homes near lead smelters, superfund sites, or in the Boston area in the early 1990s, pointing to disparities relating to work. Results from the multivariable regression model suggest that lead dust in homes of workers was associated with sociodemographic-, home-, and work-related factors, and pointed to overlapping vulnerabilities; however, a larger sample size is needed to verify findings. Results provide evidence that work-related factors are important to consider when assessing home exposures, and that take-home exposures for workers in lead high-risk jobs such as construction may be an important source of exposure in the home prime for public health intervention at work, home, and community levels.

Metals and Particulates Exposure from a Mobile E-Waste Shredding Truck: A Pilot Study.

The US electronics recycling industry has introduced a novel mobile electronic waste (e-waste) shredding truck service to address increasing needs for secure data destruction of e-waste. These trucks can shred small electronics with data security concerns at remote locations for a wide variety of clients. Shredding jobs usually involve hand-feeding electronic waste (e-waste) for 4-10 h day-1, 1-5 days. Shredding of e-waste has been documented as a source of high metal exposures, especially lead and cadmium. However, no studies have been done to assess exposures on mobile e-waste shredding trucks. We conducted a pilot cross-sectional exposure assessment on a mobile e-waste shredding truck performing a 65-min shredding job (truck back door open and no local exhaust ventilation) in the Greater Boston area in 2019. We collected area air and surface wipe samples for metals along with real-time particulate measurements from different locations. The highest metal air concentrations (e.g. 2.9 µg-lead m-3) were found next and 1.8 m away from the shredder operator inside the semi-trailer. Metal surface contamination was highest near the shredder (e.g. 1190 µg-lead 100 cm-2) and extended to other parts of the truck. Near the shredder, the concentration of ultrafine particles was up to 250 000 particles cm-3 and particulate matter 2.5 mm or less in diameter (PM2.5) was up to 171 µg m-3, and neither returned to background levels after 40 min of inactivity. A diesel-electric generator was used to power the shredder and could have contributed to some of the particulate emissions. We found that mobile e-waste shredding trucks are a source of metals and particulates emissions. We recommend the industry adopts better controls for shredding inside trucks, such as local exhaust ventilation with proper filtration and use of personal protective equipment, to protect workers' health and the environment.

Overlapping vulnerabilities in workers of the electronics recycling industry formal sector: A commentary.

Vulnerabilities in workers performing electronics recycling (e-recycling) in the informal sector worldwide have been well documented. However, the growing e-recycling industry in the formal sector still brings many challenges to protect the health of workers and their environment. This commentary aims to draw attention to the overlooked vulnerabilities faced by the workers of the e-recycling industry formal sector in high-income countries and discuss the potential impact on health inequalities experienced by these workers. Expanding the definition of vulnerability, not limited to the biological susceptibility to chemical and physical exposures, the demographic characteristics of workers in the e-recycling formal sector often reveal social groups known to be disadvantaged regarding occupational exposures and health effects, including young workers, immigrant or ethnic minorities, and workers with mental or physical health issues or disabilities. Overlapping structural vulnerabilities of the e-recycling industry stem from its newness, its working conditions, its conditions of employment, and the sociodemographic characteristics of its workforce. This phenomenon in high-income countries is not restricted to the e-recycling industry alone. It is rather a symptom of more generalized macro socioeconomical phenomena. The present challenges are in line with the new gig and green economies and changes in the global market, and their consequences on the solid waste sector. Continued efforts to strengthen the inclusion of social aspects of health into the complex interaction of the structural vulnerabilities met by e-recycling workers will be essential to anticipate and prevent health issues in this essential but still emerging workforce.

Outbreak of Norovirus Illness Among Wildfire Evacuation Shelter Populations - Butte and Glenn Counties, California, November 2018.

The Camp Fire, California's deadliest wildfire, began November 8, 2018, and was extinguished November 25 (1). Approximately 1,100 evacuees from the fire sought emergency shelter. On November 10, acute gastroenteritis (AGE) was reported in two evacuation shelters; norovirus illness was suspected, because it is commonly detected in shelter-associated AGE outbreaks. Norovirus is highly contagious and resistant to several disinfectants. Butte County Public Health Department (BCPHD), assisted by the California Department of Public Health (CDPH), initiated active surveillance to identify cases, confirm the etiology, and assess shelter infection prevention and control (IPC) practices to guide recommendations. During November 8-30, a total of 292 patients with AGE were identified among nine evacuation shelters; norovirus was detected in 16 of 17 unique patient stool specimens. Shelter IPC assessments revealed gaps in illness surveillance, isolation practices, cleaning, disinfection, and handwashing. CDPH and BCPHD collaborated with partner agencies to implement AGE screening, institute isolation protocols and 24-hour cleaning services, and promote proper hand hygiene. During disasters with limited resources, damaged infrastructure, and involvement of multiple organizations, establishing shelter disease surveillance and IPC is difficult. However, prioritizing effective surveillance and IPC at shelter activation is necessary to prevent, identify, and contain outbreaks.

Case-control study of brain and other central nervous system cancer among workers at semiconductor and storage device manufacturing facilities.

OBJECTIVE: This study evaluated the relationship between brain and other central nervous system cancer ('CNS cancer') and exposures at two semiconductor and electronic module manufacturing facilities and at a storage device manufacturing facility. METHODS: The case-control study, nested in a cohort of 126 836 employees, compared 120 CNS cancer cases and 1028 matched controls with respect to employment in 10 process groups and estimated cumulative exposure to 31 known or possible carcinogens. RESULTS: CNS cancer was associated with module manufacturing operations at two facilities. Module manufacturing is a process that begins with production of ceramic substrates followed by attachment of completed semiconductor chips and metal-containing circuitry resulting in a high performing electronic device. Positive associations with the highest tertile of estimated cumulative exposure were found for several chemicals, including 2-butoxyethanol, cyclohexanone, ortho-dichlorobenzene, cadmium, molybdenum, trichloroethylene and vinyl chloride. CONCLUSIONS: Results suggested positive associations between CNS cancer and specific operations and chemicals experienced in the semiconductor and electronic module manufacturing industry. However, lack of external support for these findings precludes a causal interpretation, and the observed associations may have been due to chance.

Eliminating Take-Home Exposures: Recognizing the Role of Occupational Health and Safety in Broader Community Health.

Toxic contaminants inadvertently brought from the workplace to the home, known as take-home or paraoccupational exposures, have often been framed as a problem that arises due to unsanitary worker behavior. This review article conceptualizes take-home exposures as a public health hazard by (i) investigating the history of take-home contaminants and how they have been studied, (ii) arguing that an ecosocial view of the problem is essential for effective prevention, (iii) summarizing key structural vulnerabilities that lead populations to be at risk, and (iv) discussing future research and prevention effort needs. This article reframes take-home exposures as one of many chronic pathways that contributes to persistent health disparities among workers, their families, and communities. Including the role of work in community health will increase the comprehensiveness of prevention efforts for contaminants such as lead and pesticides that contribute to environmental disparities.

Retrospective Exposure Assessment for Semiconductor and Storage Device Manufacturing Facilities.

OBJECTIVE: The aim of this study was to develop exposure estimates for a case-control study of central nervous system cancer in semiconductor and storage device manufacturing workers. METHODS: Over 700,000 records on sample measurements were obtained. Mean exposure intensity was estimated for 31 established/suspected carcinogens (agents of interest) in 10 primary exposure groups over three manufacturing eras. We assigned confidence ratings, based on number/type of measurements, to each estimate. RESULTS: Mean exposures decreased by an order of magnitude over the three manufacturing eras and were below applicable occupational exposure limits for 22 of 31 agents of interest. For 25 agents, at least 70% of the exposures were estimated with high confidence. CONCLUSION: This is the largest comprehensive study of exposures in the semiconductor/storage device industry and the first to include cumulative exposure estimates and measures of confidence in the exposure estimates.

Comprehension and perceptions of study participants upon receiving perfluoroalkyl substance exposure biomarker results.

BACKGROUND: Measurement of environmental biomarkers in biomedia is increasingly used as a method of exposure characterization in human population studies. Reporting the results of biomarker measurements back to study participants has been controversial, including questions of ethics and whether the study participants would want to receive and would understand the results. METHODS: Recently we mailed individual measurements of two serum biomarkers, perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) to participants in three exposure studies of persons living in the Ohio River Valley, of whom 60 were parents of children who had been sampled. Many had serum concentrations of PFOA above the US population 95th percentile value. Reporting forms used in the three studies were somewhat different (either tables or charts for comparison to US population values) and varied in complexity. With all reports, we included information about concentrations of PFOA and PFOS in the general population, and a survey designed to ascertain the opinions of the study participants about the information they received. RESULTS: Approximately 33% (273/821) returned the survey, and of those, 96% reported that they were pleased that we had sent them the report. Most (86%) responded that the results were easy to understand and the enclosed fact sheet was helpful in answering questions (87%). Regarding the amount of information, most felt that we provided the "right amount" (78%) but some "too much" (7%) and some "too little" (15%). The majority (53%) were surprised at their serum concentrations. Of those with serum values > 13.0 ng/mL, 74% responded that they thought their serum concentration was "high", but only 22% of those with serum concentrations ≤5.6 responded that their concentration was "low". Surprisingly, many talked to no one about their levels; those who did were most likely to discuss the report with family members. CONCLUSIONS: Reporting back individual environmental biomarker results is generally well received by study participants, and those with high concentrations perceived them to be high. Questions remain as to why study participants did not discuss their results with others.

Comparison of the near field/far field model and the advanced reach tool (ART) model V1.5: exposure estimates to benzene during parts washing with mineral spirits.

The Advanced Reach Tool V1.5 (ART) is a mathematical model for occupational exposures conceptually based on, but implemented differently than, the "classic" Near Field/Far Field (NF/FF) exposure model. The NF/FF model conceptualizes two distinct exposure "zones"; the near field, within approximately 1m of the breathing zone, and the far field, consisting of the rest of the room in which the exposure occurs. ART has been reported to provide "realistic and reasonable worst case" estimates of the exposure distribution. In this study, benzene exposure during the use of a metal parts washer was modeled using ART V1.5, and compared to actual measured workers samples and to NF/FF model results from three previous studies. Next, the exposure concentrations expected to be exceeded 25%, 10% and 5% of the time for the exposure scenario were calculated using ART. Lastly, ART exposure estimates were compared with and without Bayesian adjustment. The modeled parts washing benzene exposure scenario included distinct tasks, e.g. spraying, brushing, rinsing and soaking/drying. Because ART can directly incorporate specific types of tasks that are part of the exposure scenario, the present analysis identified each task's determinants of exposure and performance time, thus extending the work of the previous three studies where the process of parts washing was modeled as one event. The ART 50th percentile exposure estimate for benzene (0.425ppm) more closely approximated the reported measured mean value of 0.50ppm than the NF/FF model estimates of 0.33ppm, 0.070ppm or 0.2ppm obtained from other modeling studies of this exposure scenario. The ART model with the Bayesian analysis provided the closest estimate to the measured value (0.50ppm). ART (with Bayesian adjustment) was then used to assess the 75th, the 90th and 95th percentile exposures, predicting that on randomly selected days during this parts washing exposure scenario, 25% of the benzene exposures would be above 0.70ppm; 10% above 0.95ppm; and 5% above 1.15ppm. These exposure estimates at the three different percentiles of the ART exposure distribution refer to the modeled exposure scenario not a specific workplace or worker. This study provides a detailed comparison of modeling tools currently available to occupational hygienists and other exposure assessors. Possible applications are considered.

Polyfluoroalkyl substance exposure in the Mid-Ohio River Valley, 1991-2012.

BACKGROUND: Industrial discharges of perfluorooctanoic acid (PFOA) to the Ohio River, contaminating water systems near Parkersburg, WV, were previously associated with nearby residents' serum PFOA concentrations above US general population medians. Ohio River PFOA concentrations downstream are elevated, suggesting Mid-Ohio River Valley residents are exposed through drinking water. OBJECTIVES: Quantify PFOA and 10 other per- and polyfluoroalkyl substances (PFAS) in Mid-Ohio River Valley resident sera collected between 1991 and 2013 and determine whether the Ohio River and Ohio River Aquifer are exposure sources. METHODS: We measured eleven PFAS in 1608 sera from 931 participants. Serum PFOA concentration and water source associations were assessed using linear mixed-effects models. We estimated between-sample serum PFOA using one-compartment pharmacokinetics for participants with multiple samples. RESULTS: In serum samples collected as early as 1991, PFOA (median = 7.6 ng/mL) was detected in 99.9% of sera; 47% had concentrations greater than US population 95th percentiles. Five other PFAS were detected in greater than 82% of samples; median other PFAS concentrations were similar to the US general population. Serum PFOA was significantly associated with water source, sampling year, age at sampling, tap water consumption, pregnancy, gravidity and breastfeeding. Serum PFOA was 40-60% lower with granular activated carbon (GAC) use. Repeated measurements and pharmacokinetics suggest serum PFOA peaked 2000-2006 for participants using water without GAC treatment; where GAC was used, serum PFOA concentrations decreased from 1991 to 2012. CONCLUSIONS: Mid-Ohio River Valley residents appear to have PFOA, but not other PFAS, serum concentrations above US population levels. Drinking water from the Ohio River and Ohio River Aquifer, primarily contaminated by industrial discharges 209-666 km upstream, is likely the primary exposure source. GAC treatment of drinking water mitigates, but does not eliminate, PFOA exposure.

Headache Disorders May Be a Risk Factor for the Development of New Onset Hypothyroidism.

OBJECTIVE: To determine whether headache disorders are a risk factor for the development of new onset hypothyroidism. BACKGROUND: Past studies have reported associations between headache disorders and hypothyroidism, but the directionality of the association is unknown. METHODS: This was a longitudinal retrospective cohort study using data from the Fernald Medical Monitoring Program (FMMP). Residents received physical examinations and thyroid function testing every 3 years during the 20 year program. Residents were excluded from the cohort if there was evidence of past thyroid disease or abnormal thyroid function tests at the first office visit. A diagnosis of a headache disorder was established by self-report of "frequent headaches," use of any headache-specific medication, or a physician diagnosis of a headache disorder. The primary outcome measure was new onset hypothyroidism defined as the initiation of thyroid replacement therapy or TSH ≥ 10 without thyroid medication. A Cox survival analysis with time dependent variables were used for the model. Headache disorders, age, sex, body mass index, income, smoking, narcotic use, and hypothyroidism-producing medications were independent variables in the model. RESULTS: Data from 8412 residents enrolled in the FMMP were used in the current study. Headache disorders were present in about 26% of the residents and new onset hypothyroidism developed in ∼7%. The hazard ratio for the development of new onset hypothyroidism was 1.21 (95% CI = 1.001, 1.462) for those with headache disorders. CONCLUSIONS: Headache disorders may be associated with an increased risk for the development of new onset hypothyroidism.

Gaseous and Particulate Content of Laser Hair Removal Plume.

Importance: Potentially harmful chemicals are released when tissues are vaporized. Laser hair removal (LHR) causes heating and often vaporization of hairs, producing both a signature malodorous plume and visible particulates. Objective: To characterize the chemical composition and quantify the ultrafine particle content of the plume generated during LHR. Design, Setting, and Participants: In the laser center of a large academic hospital, discarded terminal hairs from the trunk and extremities were collected from 2 adult volunteers. The hair samples were sealed in glass gas chromatography chambers and treated with a laser. The laser plume was analyzed by gas chromatography-mass spectrometry (GC-MS). During LHR treatment, two 6-L negative pressure canisters were used to capture 30 seconds of laser plume, and a portable condensation particle counter was used to measure ultrafine particulates (<1 µm). Ultrafine particle concentrations were measured within the treatment room, within the waiting room, and outside the building. Main Outcomes and Measures: The chemical content of the laser plume was analyzed with GC-MS and screened for aerosolized toxins using Environmental Protection Agency-certified methods. The ambient concentration of ultrafine particles during LHR was measured by condensation particle counters. Results: Analysis with GC-MS identified 377 chemical compounds. Sixty-two of these compounds, of which 13 are known or suspected carcinogens and more than 20 are known environmental toxins, exhibited strong absorption peaks. During LHR, the portable condensation particle counters documented an 8-fold increase compared with the ambient room baseline level of ultrafine particle concentrations (ambient room baseline, 15 300 particles per cubic centimeter [ppc]; LHR with smoke evacuator, 129 376 ppc), even when a smoke evacuator was in close proximity (5.0 cm) to the procedure site. When the smoke evacuator was turned off for 30 seconds, there was a more than 26-fold increase in particulate count compared with ambient baseline levels (ambient baseline, 15 300 ppc; LHR without smoke evacuator for 30 seconds, 435 888 ppc). Conclusions and Relevance: These findings establish the concern that the burning-hair plume often present during LHR should be considered a biohazard, warranting the use of smoke evacuators, good ventilation, and respiratory protection, especially for health care workers with prolonged exposure to LHR plume.

Improving safety climate through a communication and recognition program for construction: a mixed methods study.

OBJECTIVES: This study aimed to evaluate the efficacy of a safety communication and recognition program (B-SAFE), designed to encourage improvement of physical working conditions and hazard reduction in construction. METHODS: A matched pair cluster randomized controlled trial was conducted on eight worksites (four received the B-SAFE intervention, four served as control sites) for approximately five months per site. Pre- and post-exposure worker surveys were collected at all sites (N=615, pre-exposure response rate of 74%, post-exposure response rate of 88%). Multi-level mixed effect regression models evaluated the effect of B-SAFE on safety climate as assessed from surveys. Focus groups (N=6-8 workers/site) were conducted following data collection. Transcripts were coded and analyzed for thematic content using Atlas.ti (version 6). RESULTS: The mean safety climate score at intervention sites, as measured on a 0-50 point scale, increased 0.5 points (1%) between pre- and post-B-SAFE exposure, compared to control sites that decreased 0.8 points (1.6%). The intervention effect size was 1.64 (3.28%) (P-value=0.01) when adjusted for month the worker started on-site, total length of time on-site, as well as individual characteristics (trade, title, age, and race/ethnicity). At intervention sites, workers noted increased levels of safety awareness, communication, and teamwork compared to control sites. CONCLUSIONS: B-SAFE led to many positive changes, including an improvement in safety climate, awareness, teambuilding, and communication. B-SAFE was a simple intervention that engaged workers through effective communication infrastructures and had a significant, positive effect on worksite safety.

Hypercholesterolemia with consumption of PFOA-laced Western diets is dependent on strain and sex of mice.

Perfluorooctanoic acid (PFOA) is a man-made surfactant with a number of industrial applications. It has a long half-life environmentally and biologically. Past studies suggest a direct relationship between plasma cholesterol and PFOA serum concentrations in humans and an inverse one in rodents fed standard rodent chow, making it difficult to examine mechanisms responsible for the potential PFOA-induced hypercholesterolemia and altered sterol metabolism. To examine dietary modification of PFOA-induced effects, C57BL/6 and BALB/c mice were fed PFOA in a fat- and cholesterol-containing diet. When fed these high fat diets, PFOA ingestion resulted in marked hypercholesterolemia in male and female C57BL/6 mice and less robust hypercholesterolemia in male BALB/c mice. The PFOA-induced hypercholesterolemia appeared to be the result of increased liver masses and altered expression of genes associated with hepatic sterol output, specifically bile acid production. mRNA levels of genes associated with sterol input were reduced only in C57BL/6 females, the mice with the greatest increase in plasma cholesterol levels. Strain-specific PFOA-induced changes in cholesterol concentrations in mammary tissues and ovaries paralleled changes in plasma cholesterol levels. mRNA levels of sterol-related genes were reduced in ovaries of C57BL/6 but not in BALB/c mice and not in mammary tissues. Our data suggest that PFOA ingestion leads to hypercholesterolemia in mice fed fat and cholesterol and effects are dependent upon the genetic background and gender of the mice with C57BL/6 female mice being most responsive to PFOA.