The Centers for Disease Control and Prevention (CDC) Radiation Laboratory’s primary mission is to provide laboratory support for an effective and efficient response to public health radiological emergencies. The laboratory has developed methods for several radiological threat agents, including Iridium-192 (Ir-192). Ir-192 can be analyzed via its gamma energy through analytical methods such as High Purity Germanium (HPGe) and its beta energy through Liquid Scintillation Counting (LSC). In this work, we present and compare HPGe and LSC rapid response methods for Ir-192 quantification. Both methods show the reasonable results and can be used in emergency situations. © This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply 2024.

Liquid Scintillation Counting (LSC) gross alpha/beta screening is a valuable tool for providing rapid laboratory response for the analysis of human clinical urine samples during a large-scale radiation incident event. Verification of method performance, as required for clinical laboratory testing, is accomplished by the evaluation of routine, periodic measurements of radioactive spiked samples for quality control, performance testing, and accuracy checks. Radionuclide stability of alpha and beta emitters in urine for LSC analysis is an important consideration. The purpose of this work is to demonstrate optimal preparations and storage conditions of samples used for method verification. © This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply 2024.

Rapid detection and quantification of gross alpha/beta-emitting radionuclides by liquid scintillation counting (LSC) is vital in guiding response to a nuclear or radiological incidents. Liquid scintillation counters use signal pulse shape to discriminate alpha and beta events in samples but require precise optimization to minimize the spillover, or misclassification, of those events. In this study, samples at varying activity levels were analyzed by LSC to determine the effect of activity level, emitter type, and sample matrix on spillover. Analysis proved a matrix effect and a direct correlation of activity level on spillover percentage for both alpha and beta emitting-nuclides. © 2023, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.

The measurement of uranium (U) isotope ratios in urine provides valuable information about the source of U exposure in humans and can be vitally important in a radiological emergency. This method provides rapid and accurate results for 235U/238U at 235U concentrations as low as 0.42 ng/L, which is equivalent to ~ 200 ng/L of total U for a depleted U (DU) at a 235U/238U ratio of ~ 0.002. The results are within 6% of Certified Reference Materials target values and agree with Department of Defense Armed Forces Institute of Pathology inter-laboratory comparison target values with a bias range of -6.9–7.6%. © 2022, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.

CDC designed a rapid HPGe Bioassay Method for (137)Cs, (60)Co, and (192)Ir that is suitable for a public health response to a radiological incident where people may ingest or inhale radionuclides. The method uses a short count time, small sample volume, and a large volume detector and well size. It measures a patient's urine sample collected post-incident. The levels of concern are directly related to the Clinical Decision Guide levels recommended in the National Council of Radiation Protection 161.

A growing number of carbon nanotubes and nanofibers (CNT/F) exposure and epidemiologic studies have utilized 25- and 37-mm open-faced cassettes (OFCs) to assess the inhalable aerosol fraction. It has been previously established that the 37-mm OFC undersamples particles >20 µm in diameter, but the size-selective characteristics of the 25-mm OFC have not yet been fully evaluated. This article describes an experimental study conducted to determine if the 25- and 37-mm OFCs performed with relative equivalence to a reference inhalable aerosol sampler when challenged with CNT/F particles. Side-by-side paired samples were collected within a small Venturi chamber using a 25-mm styrene OFC, 37-mm styrene OFC, 25-mm aluminum OFC, and button inhalable aerosol sampler. Three types of CNT/F materials and an Arizona road dust were used as challenge aerosols for the various sampler configurations. Repeated experiments were conducted for each sampler configuration and material. The OFC samplers operated at flow rates of 2 and 5 L/min. Results showed that the 25-mm OFC performed comparably to the button sampler when challenged with CNT/F aerosols, which was demonstrated in five of the six experimental scenarios with an average error of 21%. Overall, the results of this study indicate that the sampling efficiency of the 25- and 37-mm OFCs adequately followed the ISO/ACGIH/CEN inhalable sampling convention when challenged with CNT/F aerosols. Past exposure and epidemiologic studies that used these OFC samplers can directly compare their results to studies that have used other validated inhalable aerosol samplers. ©, This work was authored as part of the Contributor’s official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.

All survey items reflect some conceptual framework that might or might not be accepted by subgroups with certain personal identities. For example, respondents with certain religious identities may reject the scientific framework of questions about the development of life and origins of the universe since there are competing truth claims between religion and science on these topics. Since the late 1970s, the National Science Foundation has sponsored a series of surveys to gauge public attitudes toward and understanding of science and technology. Items that simultaneously measure knowledge and acceptance of two concepts-evolution and the "big bang"-appear to raise measurement problems for a specific subgroup that rejects the premise of the items. This paper focuses on alternative versions of the survey questions that attempt to remove the effect of religious belief on answers to these items. We investigate two approaches for removing this confounding of knowledge and acceptance. One approach is to ask what scientists think rather than what the respondents believe; the other is to remove "hot-button" features of the question likely to trigger conflicts between the religious and scientific views. We also illustrate how psychometric methods (such as confirmatory factor analysis) can help sort out which version of the questions produces the most valid answers.

Background: Most nursing facilities (NFs) lack methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) surveillance programs due to limited resources and high costs. We investigated the utility of environmental screening of high-touch surfaces in patient rooms as a way to circumvent these challenges. Methods: We compared MRSA and VRE culture data from high-touch surfaces in patients' rooms (14450 samples from 6 NFs) and ranked each site's performance in predicting patient colonization (7413 samples). The best-performing sites were included in a MRSA- and a VRE-specific panel that functioned as a proxy for patient colonization. Molecular typing was performed to confirm available concordant patient-environment pairs. Results: We identified and validated a MRSA panel that consisted of the bed controls, nurse call button, bed rail, and TV remote control. The VRE panel included the toilet seat, bed controls, bed rail, TV remote control, and top of the side table. Panel colonization data tracked patient colonization. Negative predictive values were 89%-92% for MRSA and 82%-84% for VRE. Molecular typing confirmed a strong clonal type relationship in available concordant patient-environment pairs (98% for MRSA, 91% for VRE), pointing to common epidemiological patterns for environmental and patient isolates. Conclusions: Environmental panels used as a proxy for patient colonization and incorporated into facility surveillance protocols can guide decolonization strategies, improve awareness of MRSA and VRE burden, and inform efforts to reduce transmission. Targeted environmental screening may be a viable surveillance strategy for MRSA and VRE detection in NFs.

Risk of inhalation exposure to viable Bacillus anthracis (B. anthracis) spores has primarily been assessed using short-term, stationary sampling methods which may not accurately characterize the concentration of inhalable-sized spores reaching a person's breathing zone. While a variety of aerosol sampling methods have been utilized during previous anthrax responses, no consensus has yet been established for personal air sampling. The goal of this study was to determine the best sampler-filter combination(s) for the collection and extraction of B. anthracis spores. The study was designed to 1) evaluate the performance of four filter types [one mixed cellulose ester, MCE (pore size = 3 microm), two polytetrafluoroethylene, PTFE (1 and 3 microm), and one polycarbonate, PC (3 microm)], and 2) evaluate the best performing filters in two commercially-available inhalable aerosol samplers (IOM and Button). Bacillus thuringiensis kurstaki [Bt(k)], a simulant for B. anthracis, served as the aerosol challenge. The filters were assessed based on criteria such as ability to maintain low pressure drop over an extended sampling period, filter integrity under various environmental conditions, spore collection and extraction efficiencies, ease of loading and unloading the filters into the samplers, cost, and availability. Three of four tested collection filters - except MCE - were found suitable for efficient collection and recovery of Bt(k) spores sampled from dry and humid as well as dusty and clean air environments for up to 8 h. The PC (3 microm) filter was identified as the best performing filter in this study. The PTFE (3 microm) demonstrated a comparable performance, but it is more costly. Slightly higher concentrations were measured with the IOM inhalable sampler which is the preferred sampler's performance criterion when detecting a highly pathogenic agent with no established "safe" inhalation exposure level. Additional studies are needed to address the effects of environmental conditions and spore concentration. The data obtained in this investigation are crucial for future efforts on the development and optimization of a method for assessing inhalation exposure to B. anthracis.

OBJECTIVE To determine the typical microbial bioburden (overall bacterial and multidrug-resistant organisms [MDROs]) on high-touch healthcare environmental surfaces after routine or terminal cleaning. DESIGN Prospective 2.5-year microbiological survey of large surface areas (>1,000 cm2). SETTING MDRO contact-precaution rooms from 9 acute-care hospitals and 2 long-term care facilities in 4 states. PARTICIPANTS Samples from 166 rooms (113 routine cleaned and 53 terminal cleaned rooms). METHODS Using a standard sponge-wipe sampling protocol, 2 composite samples were collected from each room; a third sample was collected from each Clostridium difficile room. Composite 1 included the TV remote, telephone, call button, and bed rails. Composite 2 included the room door handle, IV pole, and overbed table. Composite 3 included toileting surfaces. Total bacteria and MDROs (ie, methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci [VRE], Acinetobacter baumannii, Klebsiella pneumoniae, and C. difficile) were quantified, confirmed, and tested for drug resistance. RESULTS The mean microbial bioburden and range from routine cleaned room composites were higher (2,700 colony-forming units [CFU]/100 cm2; ≤1-130,000 CFU/100 cm2) than from terminal cleaned room composites (353 CFU/100 cm2; ≤1-4,300 CFU/100 cm2). MDROs were recovered from 34% of routine cleaned room composites (range ≤1-13,000 CFU/100 cm2) and 17% of terminal cleaned room composites (≤1-524 CFU/100 cm2). MDROs were recovered from 40% of rooms; VRE was the most common (19%). CONCLUSIONS This multicenter bioburden summary provides a first step to determining microbial bioburden on healthcare surfaces, which may help provide a basis for developing standards to evaluate cleaning and disinfection as well as a framework for studies using an evidentiary hierarchy for environmental infection control. Infect Control Hosp Epidemiol 2016;1-7.

There is a need for toxicity tests capable of recognizing indoor environments with compromised air quality, especially in the context of moisture damage. One of the key issues is sampling, which should both provide meaningful material for analyses and fulfill requirements imposed by practitioners using toxicity tests for health risk assessment. We aimed to evaluate different existing methods of sampling indoor particulate matter (PM) to develop a suitable sampling strategy for a toxicological assay. During three sampling campaigns in moisture-damaged and non-damaged school buildings, we evaluated one passive and three active sampling methods: the Settled Dust Box (SDB), the Button Aerosol Sampler, the Harvard Impactor and the National Institute for Occupational Safety and Health (NIOSH) Bioaerosol Cyclone Sampler. Mouse RAW264.7 macrophages were exposed to particle suspensions and cell metabolic activity (CMA), production of nitric oxide (NO) and tumor necrosis factor (TNFalpha) were determined after 24 h of exposure. The repeatability of the toxicological analyses was very good for all tested sampler types. Variability within the schools was found to be high especially between different classrooms in the moisture-damaged school. Passively collected settled dust and PM collected actively with the NIOSH Sampler (Stage 1) caused a clear response in exposed cells. The results suggested the higher relative immunotoxicological activity of dust from the moisture-damaged school. The NIOSH Sampler is a promising candidate for the collection of size-fractionated PM to be used in toxicity testing. The applicability of such sampling strategy in grading moisture damage severity in buildings needs to be developed further in a larger cohort of buildings.

Ambient bioaerosols are ubiquitous in the daily environment and can affect health in various ways. However, few studies have been conducted to comprehensively evaluate personal bioaerosol exposure in occupational and indoor environments because of the complex composition of bioaerosols and the lack of standardized sampling/analysis methods. We conducted a study to determine the most efficient collection/analysis method for the personal exposure assessment of multiple bioaerosols. The sampling efficiencies of three filters and four samplers were compared. According to our results, polycarbonate (PC) filters had the highest relative efficiency, particularly for bacteria. Side-by-side sampling was conducted to evaluate the three filter samplers (with PC filters) and the NIOSH Personal Bioaerosol Cyclone Sampler. According to the results, the Button Aerosol Sampler and the IOM Inhalable Dust Sampler had the highest relative efficiencies for fungi and bacteria, followed by the NIOSH sampler. Personal sampling was performed in a pig farm to assess occupational bioaerosol exposure and to evaluate the sampling/analysis methods. The Button and IOM samplers yielded a similar performance for personal bioaerosol sampling at the pig farm. However, the Button sampler is more likely to be clogged at high airborne dust concentrations because of its higher flow rate (4 L/min). Therefore, the IOM sampler is a more appropriate choice for performing personal sampling in environments with high dust levels. In summary, the Button and IOM samplers with PC filters are efficient sampling/analysis methods for the personal exposure assessment of multiple bioaerosols.

The current measurement method for occupational exposure to wood dust is by gravimetric analysis and is thus non-specific. In this work, diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) for the analysis of only the wood component of dust was further evaluated by analysis of the same samples between two laboratories. Field samples were collected from six wood product factories using 25-mm glass fiber filters with the Button aerosol sampler. Gravimetric mass was determined in one laboratory by weighing the filters before and after aerosol collection. Diffuse reflection mid-infrared spectra were obtained from the wood dust on the filter which is placed on a motorized stage inside the spectrometer. The metric used for the DRIFTS analysis was the intensity of the carbonyl band in cellulose and hemicellulose at ~1735cm-1. Calibration curves were constructed separately in both laboratories using the same sets of prepared filters from the inhalable sampling fraction of red oak, southern yellow pine, and western red cedar in the range of 0.125-4mg of wood dust. Using the same procedure in both laboratories to build the calibration curve and analyze the field samples, 62.3% of the samples measured within 25% of the average result with a mean difference between the laboratories of 18.5%. Some observations are included as to how the calibration and analysis can be improved. In particular, determining the wood type on each sample to allow matching to the most appropriate calibration increases the apparent proportion of wood dust in the sample and this likely provides more realistic DRIFTS results.

BACKGROUND: Although working smoke alarms halve deaths in residential fires, many households do not keep alarms operational. We tested whether theory-based education increases alarm operability. METHODS: Randomised multiarm trial, with a single arm randomly selected for use each day, in low-income neighbourhoods in Maryland, USA. Intervention arms: (1) Full Education combining a health belief module with a social-cognitive theory module that provided hands-on practice installing alarm batteries and using the alarm's hush button; (2) Hands-on Practice social-cognitive module supplemented by typical fire department education; (3) Current Norm receiving typical fire department education only. Four hundred and thirty-six homes recruited through churches or by knocking on doors in 2005-2008. Follow-up visits checked alarm operability in 370 homes (85%) 1-3.5 years after installation. Main outcome measures: number of homes with working alarms defined as alarms with working batteries or hard-wired and number of working alarms per home. Regressions controlled for alarm status preintervention; demographics and beliefs about fire risks and alarm effectiveness. RESULTS: Homes in the Full Education and Practice arms were more likely to have a functioning smoke alarm at follow-up (OR=2.77, 95% CI 1.09 to 7.03) and had an average of 0.32 more working alarms per home (95% CI 0.09 to 0.56). Working alarms per home rose 16%. Full Education and Practice had similar effectiveness (p=0.97 on both outcome measures). CONCLUSIONS: Without exceeding typical fire department installation time, installers can achieve greater smoke alarm operability. Hands-on practice is key. Two years after installation, for every three homes that received hands-on practice, one had an additional working alarm. TRIAL REGISTRATION NUMBER: http://www.clinicaltrials.gov number NCT00139126.

Emerging concerns regarding the toxicity of inhaled wood dust support the need for techniques to quantitate wood content of mixed industrial dusts. The diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis technique was applied to the determination of wood content of 181 inhalable dust samples (geometric mean concentration: 0.895mg/m(3); geometric standard deviation: 2.73) collected from six wood product industry factories using 25 mm glass fibre filters with the Button aerosol sampler. Prior to direct DRIFTS analysis the filter samples were treated with ethyl acetate and re-deposited uniformly. Standards ranging from 125 mcg to 4000 mcg were prepared for red oak, southern yellow pine, and red cedar and used for quantitation of samples depending upon the wood materials present at a given factory. The oak standards spectra were quantitated by linear regression of response in Kubelka-Munk units at 1736 cm(-1), whereas the pine standards and the cedar standards spectra were quantitated by polynomial regression of response in log 1/R units at 1734 cm(-1), with the selected wavenumbers corresponding to stretching vibration of free C=O from cellulose and hemicelluloses. For one factory which used both soft- and hard-woods, a separate polynomial standard curve was created by proportionally combining the oak and pine standards polynomial regression equations based on response (log 1/R) at 1734 cm(-1). The analytical limits of detection were approximately 52 mcg of oak, 20 mcg of pine, 30 mcg of cedar, and 16 mcg of mixed oak and pine for the factory with mixed woods. Overall, the average of dry wood dust percentage of inhalable dust was approximately 56% and the average dry wood dust weight was 0.572 mg for the Button samples. Across factories, there were statistically significant differences (p<0.001) for the percentage of dry wood dust in inhalable dust with factory averages ranging from 33.5 to 97.6%.

The National Institute for Occupational Safety and Health (NIOSH) investigators compared methods for collecting personal breathing zone (PBZ) air samples for particulates during abrasive blasting at a shipyard. Abrasive blasting is the cleaning or finishing of surfaces by the use of an abrasive carried in a strong current of air. The U.S. government has provided regulatory requirements and guidelines for ventilation, enclosures, and personal protective equipment during abrasive blasting [NIOSH 1987; OSHA 2012a]. However, current Occupational Safety and Health Administration (OSHA) sampling and analytical methods can overestimate worker exposures to airborne metals and other particulate contaminants during abrasive blasting [NIOSH 1994; NIOSH 1998; OSHA 2012b]. | Shielding the 37-mm filter cassette inlet to exclude non-inhalable particles, mounting the PBZ air sampler behind the employee's head to protect the sampler from rebounding abrasive materials, and using the Institute of Medicine inhalable dust sampler, have been proposed as alternatives to assess exposure. All were found to be impractical or ineffective in abrasive blasting environments [NIOSH 1994, 1998]. Sampling simultaneously inside and outside the employees' abrasive blast hood has shown that the lower air concentrations inside the abrasive blast hood produce less overloading of the 37-mm cassettes [NIOSH 1998]; however, sampling inside PPE is not accepted by OSHA for compliance purposes [OSHA 2012a, b]. | Aizenberg et al. [2000] used a Button Aerosol Sampler® (BAS) (part number 225–360, SKC Inc., Eighty Four, Pennsylvania) with a prototype shield to evaluate PBZ exposures during abrasive blasting operations. The investigators reported that the protective shield prevented non-inhalable particles from overloading the filter and did not interfere with sampling smaller particles; however, the researchers did not determine whether the prototype protective shield altered the collection efficiency of the BAS. Following the Aizenberg et al. [2000] study, SKC Inc. designed a snap-on dome-shaped stainless steel protective secondary shield for use with the BAS when sampling during abrasive blasting (Abrasive Blasting Sampler for Heavy Metals kit, part number 225–367, SKC Inc., Eighty Four, Pennsylvania). This shield differed in size, shape, and screen opening from the prototype screen tested by Aizenberg et al. [2000]. Due to uncertainty about possible effects that shielding may have on the performance characteristics of the BAS, the objectives of this evaluation were to: (1) compare the commercially available BAS (with and without the shield) with the conventional 37-mm cassette sampler in an abrasive blasting environment and (2) evaluate whether the protective shield designed for the BAS prevented inertia-driven particles from entering and possibly overloading the sampler [NIOSH 2012a].

Recent recommendations for wood dust sampling include sampling according to the inhalable convention of International Organization for Standardization (ISO) 7708 (1995) Air quality-particle size fraction definitions for health-related sampling. However, a specific sampling device is not mandated, and while several samplers have laboratory performance approaching theoretical for an 'inhalable' sampler, the best choice of sampler for wood dust is not clear. A side-by-side field study was considered the most practical test of samplers as laboratory performance tests consider overall performance based on a wider range of particle sizes than are commonly encountered in the wood products industry. Seven companies in the wood products industry of the Southeast USA (MS, KY, AL, and WV) participated in this study. The products included hardwood flooring, engineered hardwood flooring, door skins, shutter blinds, kitchen cabinets, plywood, and veneer. The samplers selected were 37-mm closed-face cassette with ACCU-CAP, Button, CIP10-I, GSP, and Institute of Occupational Medicine. Approximately 30 of each possible pairwise combination of samplers were collected as personal sample sets. Paired samplers of the same type were used to calculate environmental variance that was then used to determine the number of pairs of samples necessary to detect any difference at a specified level of confidence. Total valid sample number was 888 (444 valid pairs). The mass concentration of wood dust ranged from 0.02 to 195 mg m(-3). Geometric mean (geometric standard deviation) and arithmetic mean (standard deviation) of wood dust were 0.98 mg m(-3) (3.06) and 2.12 mg m(-3) (7.74), respectively. One percent of the samples exceeded 15 mg m(-3), 6% exceeded 5 mg m(-3), and 48% exceeded 1 mg m(-3). The number of collected pairs is generally appropriate to detect a 35% difference when outliers (negative mass loadings) are removed. Statistical evaluation of the nonsimilar sampler pair results produced a finding of no significant difference between any pairing of sampler type. A practical consideration for sampling in the USA is that the ACCU-CAP is similar to the sampler currently used by the Occupational Safety and Health Administration for purposes of demonstrating compliance with its permissible exposure limit for wood dust, which is the same as for Particles Not Otherwise Regulated, also known as inert dust or nuisance dust (Method PV2121).