Last data update: Sep 16, 2024. (Total: 47680 publications since 2009)
Records 1-30 (of 177 Records) |
Query Trace: Wells J [original query] |
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A case study of shale gas well casing deformation in longwall chain pillars under deep cover
Zhang P , Su D , Van Dyke M , Kim BH . Rock Mech Rock Eng 2024 Shale gas wells located in longwall chain pillars are subject to longwall-induced subsurface ground movements. Longwall mining on either side of the chain pillars can induce deformations in gas well casings. Excessive casing deformations could diminish casing integrity so that intrusive shale gas might leak into the longwall mine jeopardizing mine safety. This study investigated longwall-induced casing deformations of eight shale gas wells in the chain pillars between two adjacent longwall panels in the Pittsburgh coal seam under a cover depth of 314 m. The casing deformations were measured with a 56-arm caliper after each longwall face passed the gas well pad. Casing deformations were detected at ten locations below the surface after first panel mining, and the maximum casing deformation of 1.27 cm occurred at a 184-m depth. After second panel mining, the caliper survey showed that casing deformation locations remained the same, but generally the deformations increased slightly. The maximum deformation at the 184-m depth increased from 1.27 to 1.5 cm. The eight shale gas wells were also modeled by the FLAC3D modeling technique. The casing deformations predicted by the FLAC3D model were compared with the caliper survey results. The modeling predictions were in a good agreement with the caliper measurements in terms of deformation level and locations. The modeling results suggested that the gas well setback distance to the longwall gob would affect casing deformations, and that casing deformations can be minimized if gas wells are located around the center of the abutment pillar. The study showed that longwall-induced casing deformations occur at the same weak/strong rock interfaces after both first and second panel mining. The study also showed that, under deep cover, casing deformations above the coal seam horizon are smaller than those under shallow cover. Under deep cover, the production casing deformations evaluated in this study were demonstrated to be minimized by locating gas wells at the center of the chain pillars and by leaving the production casing uncemented from the surface to below the coal seam. © This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply 2024. |
A one health approach for monitoring antimicrobial resistance: developing a national freshwater pilot effort
Franklin AM , Weller DL , Durso LM , Bagley M , Davis BC , Frye JG , Grim CJ , Ibekwe AM , Jahne MA , Keely SP , Kraft AL , McConn BR , Mitchell RM , Ottesen AR , Sharma M , Strain EA , Tadesse DA , Tate H , Wells JE , Williams CF , Cook KL , Kabera C , McDermott PF , Garland JL . Front Water 2024 6 Antimicrobial resistance (AMR) is a world-wide public health threat that is projected to lead to 10 million annual deaths globally by 2050. The AMR public health issue has led to the development of action plans to combat AMR, including improved antimicrobial stewardship, development of new antimicrobials, and advanced monitoring. The National Antimicrobial Resistance Monitoring System (NARMS) led by the United States (U.S) Food and Drug Administration along with the U.S. Centers for Disease Control and U.S. Department of Agriculture has monitored antimicrobial resistant bacteria in retail meats, humans, and food animals since the mid 1990's. NARMS is currently exploring an integrated One Health monitoring model recognizing that human, animal, plant, and environmental systems are linked to public health. Since 2020, the U.S. Environmental Protection Agency has led an interagency NARMS environmental working group (EWG) to implement a surface water AMR monitoring program (SWAM) at watershed and national scales. The NARMS EWG divided the development of the environmental monitoring effort into five areas: (i) defining objectives and questions, (ii) designing study/sampling design, (iii) selecting AMR indicators, (iv) establishing analytical methods, and (v) developing data management/analytics/metadata plans. For each of these areas, the consensus among the scientific community and literature was reviewed and carefully considered prior to the development of this environmental monitoring program. The data produced from the SWAM effort will help develop robust surface water monitoring programs with the goal of assessing public health risks associated with AMR pathogens in surface water (e.g., recreational water exposures), provide a comprehensive picture of how resistant strains are related spatially and temporally within a watershed, and help assess how anthropogenic drivers and intervention strategies impact the transmission of AMR within human, animal, and environmental systems. |
Alcohol, no ordinary commodity: Policy implications for Canada
Crépault JF , Naimi TS , Rehm J , Shield KD , Wells S , Wettlaufer A , Babor TF . Front Public Health 2024 12 1335865 Alcohol is a favorite psychoactive substance of Canadians. It is also a leading risk factor for death and disability, playing a causal role in a broad spectrum of health and social issues. Alcohol: No Ordinary Commodity is a collaborative, integrative review of the scientific literature. This paper describes the epidemiology of alcohol use and current state of alcohol policy in Canada, best practices in policy identified by the third edition of Alcohol: No Ordinary Commodity, and the implications for the development of effective alcohol policy in Canada. Best practices - strongly supported by the evidence, highly effective in reducing harm, and relatively low-cost to implement - have been identified. Measures that control affordability, limit availability, and restrict marketing would reduce population levels of alcohol consumption and the burden of disease attributable to it. |
Cost-effectiveness of mask mandates on subways to prevent SARS-CoV-2 transmission in the United States
Park J , Joo H , Kim D , Mase S , Christensen D , Maskery BA . PLoS One 2024 19 (5) e0302199 BACKGROUND: Community-based mask wearing has been shown to reduce the transmission of SARS-CoV-2. However, few studies have conducted an economic evaluation of mask mandates, specifically in public transportation settings. This study evaluated the cost-effectiveness of implementing mask mandates for subway passengers in the United States by evaluating its potential to reduce COVID-19 transmission during subway travel. MATERIALS AND METHODS: We assessed the health impacts and costs of subway mask mandates compared to mask recommendations based on the number of infections that would occur during subway travel in the U.S. Using a combined box and Wells-Riley infection model, we estimated monthly infections, hospitalizations, and deaths averted under a mask mandate scenario as compared to a mask recommendation scenario. The analysis included costs of implementing mask mandates and COVID-19 treatment from a limited societal perspective. The cost-effectiveness (net cost per averted death) of mandates was estimated for three different periods based on dominant SARS-CoV-2 variants: Alpha, Beta, and Gamma (November 2020 to February 2021); Delta (July to October 2021); and early Omicron (January to March 2022). RESULTS: Compared with mask recommendations only, mask mandates were cost-effective across all periods, with costs per averted death less than a threshold of $11.4 million (ranging from cost-saving to $3 million per averted death). Additionally, mask mandates were more cost-effective during the early Omicron period than the other two periods and were cost saving in January 2022. Our findings showed that mandates remained cost-effective when accounting for uncertainties in input parameters (e.g., even if mandates only resulted in small increases in mask usage by subway ridership). CONCLUSIONS: The findings highlight the economic value of mask mandates on subways, particularly during high virus transmissibility periods, during the COVID-19 pandemic. This study may inform stakeholders on mask mandate decisions during future outbreaks of novel viral respiratory diseases. |
A survey of state and local practices encouraging pediatric COVID-19 vaccination of children ages 6 months through 11 years
Koneru A , Wells K , Amanda Carnes C , Drumhiller K , Chatham-Stephens K , Melton M , Oliphant H , Hall S , Dennison C , Fiscus M , Vogt T . Vaccine 2024 OBJECTIVE: This report highlights state and local practices for optimizing the pediatric COVID-19 vaccination program for children ages 6 months through 11 years. METHODS: State and local practices designed to optimize pediatric COVID-19 vaccine uptake were identified from a range of sources, including immunization program, CDC, and partner staff; and media stories or program descriptions identified via online searches. RESULTS: A range of practices were identified across different categories: provider-focused practices, school-based practices, jurisdiction or health department-based activities, community-focused practices involving partners, use of vaccination incentives, and Medicaid-related practices. CONCLUSIONS: Immunization programs and stakeholders implemented a variety of practices to meet the challenge of the pediatric COVID-19 vaccination program. The key findings may serve to inform not only the current pediatric COVID-19 vaccination program, but also future outbreak response work and routine immunization activities. |
shinyMBA: a novel R shiny application for quality control of the multiplex bead assay for serosurveillance studies
Matson Z , Cooley G , Parameswaran N , Simon A , Bankamp B , Coughlin MM . Sci Rep 2024 14 (1) 7442 The multiplex bead assay (MBA) based on Luminex xMAP technology can be used as a tool to measure seroprevalence as part of population immunity evaluations to multiple antigens in large-scale serosurveys. However, multiplexing several antigens presents challenges for quality control (QC) assessments of the data because multiple parameters must be evaluated for each antigen. MBA QC parameters include monitoring bead counts and median fluorescence intensity (MFI) for each antigen in plate wells, and performance of assay controls included on each plate. Analyzing these large datasets to identify plates failing QC standards presents challenges for many laboratories. We developed a novel R Shiny application, shinyMBA, to expedite the MBA QC processes and reduce the risk of user error. The app allows users to rapidly merge multi-plate assay outputs to evaluate bead count, MFI, and performance of assay controls using statistical process control charts for all antigen targets simultaneously. The utility of the shinyMBA application and its various outputs are demonstrated using data from 32 synthetic xPONENT files with 3 multiplex antigens and two population serosurveillance studies that evaluated 1200 and 3871 samples, respectively, for 20 multiplexed antigens. The shinyMBA open-source code is available for download and modification at https://github.com/CDCgov/shinyMBA . Incorporation of shinyMBA into Luminex serosurveillance workflows can vastly improve the speed and accuracy of QC processes. |
Surveillance of waterborne disease outbreaks associated with drinking water - United States, 2015-2020
Kunz JM , Lawinger H , Miko S , Gerdes M , Thuneibat M , Hannapel E , Roberts VA . MMWR Surveill Summ 2024 73 (1) 1-23 PROBLEM/CONDITION: Public health agencies in U.S. states, territories, and freely associated states investigate and voluntarily report waterborne disease outbreaks to CDC through the National Outbreak Reporting System (NORS). This report summarizes NORS drinking water outbreak epidemiologic, laboratory, and environmental data, including data for both public and private drinking water systems. The report presents outbreak-contributing factors (i.e., practices and factors that lead to outbreaks) and, for the first time, categorizes outbreaks as biofilm pathogen or enteric illness associated. PERIOD COVERED: 2015-2020. DESCRIPTION OF SYSTEM: CDC launched NORS in 2009 as a web-based platform into which public health departments voluntarily enter outbreak information. Through NORS, CDC collects reports of enteric disease outbreaks caused by bacterial, viral, parasitic, chemical, toxin, and unknown agents as well as foodborne and waterborne outbreaks of nonenteric disease. Data provided by NORS users, when known, for drinking water outbreaks include 1) the number of cases, hospitalizations, and deaths; 2) the etiologic agent (confirmed or suspected); 3) the implicated type of water system (e.g., community or individual or private); 4) the setting of exposure (e.g., hospital or health care facility; hotel, motel, lodge, or inn; or private residence); and 5) relevant epidemiologic and environmental data needed to describe the outbreak and characterize contributing factors. RESULTS: During 2015-2020, public health officials from 28 states voluntarily reported 214 outbreaks associated with drinking water and 454 contributing factor types. The reported etiologies included 187 (87%) biofilm associated, 24 (11%) enteric illness associated, two (1%) unknown, and one (<1%) chemical or toxin. A total of 172 (80%) outbreaks were linked to water from public water systems, 22 (10%) to unknown water systems, 17 (8%) to individual or private systems, and two (0.9%) to other systems; one (0.5%) system type was not reported. Drinking water-associated outbreaks resulted in at least 2,140 cases of illness, 563 hospitalizations (26% of cases), and 88 deaths (4% of cases). Individual or private water systems were implicated in 944 (43%) cases, 52 (9%) hospitalizations, and 14 (16%) deaths.Enteric illness-associated pathogens were implicated in 1,299 (61%) of all illnesses, and 10 (2%) hospitalizations. No deaths were reported. Among these illnesses, three pathogens (norovirus, Shigella, and Campylobacter) or multiple etiologies including these pathogens resulted in 1,225 (94%) cases. The drinking water source was identified most often (n = 34; 7%) as the contributing factor in enteric disease outbreaks. When water source (e.g., groundwater) was known (n = 14), wells were identified in 13 (93%) of enteric disease outbreaks.Most biofilm-related outbreak reports implicated Legionella (n = 184; 98%); two nontuberculous mycobacteria (NTM) (1%) and one Pseudomonas (0.5%) outbreaks comprised the remaining. Legionella-associated outbreaks generally increased over the study period (14 in 2015, 31 in 2016, 30 in 2017, 34 in 2018, 33 in 2019, and 18 in 2020). The Legionella-associated outbreaks resulted in 786 (37%) of all illnesses, 544 (97%) hospitalizations, and 86 (98%) of all deaths. Legionella also was the outbreak etiology in 160 (92%) public water system outbreaks. Outbreak reports cited the premise or point of use location most frequently as the contributing factor for Legionella and other biofilm-associated pathogen outbreaks (n = 287; 63%). Legionella was reported to NORS in 2015 and 2019 as the cause of three outbreaks in private residences (2). INTERPRETATION: The observed range of biofilm and enteric drinking water pathogen contributing factors illustrate the complexity of drinking water-related disease prevention and the need for water source-to-tap prevention strategies. Legionella-associated outbreaks have increased in number over time and were the leading cause of reported drinking water outbreaks, including hospitalizations and deaths. Enteric illness outbreaks primarily linked to wells represented approximately half the cases during this reporting period. This report enhances CDC efforts to estimate the U.S. illness and health care cost impacts of waterborne disease, which revealed that biofilm-related pathogens, NTM, and Legionella have emerged as the predominant causes of hospitalizations and deaths from waterborne- and drinking water-associated disease. PUBLIC HEALTH ACTION: Public health departments, regulators, and drinking water partners can use these findings to identify emerging waterborne disease threats, guide outbreak response and prevention programs, and support drinking water regulatory efforts. |
Nitrate exposure from drinking water and dietary sources among Iowa farmers using private wells
Skalaban TG , Thompson DA , Madrigal JM , Blount BC , Espinosa MM , Kolpin DW , Deziel NC , Jones RR , Freeman LB , Hofmann JN , Ward MH . Sci Total Environ 2024 170922 Nitrate levels are increasing in water resources across the United States and nitrate ingestion from drinking water has been associated with adverse health risks in epidemiologic studies at levels below the maximum contaminant level (MCL). In contrast, dietary nitrate ingestion has generally been associated with beneficial health effects. Few studies have characterized the contribution of both drinking water and dietary sources to nitrate exposure. The Agricultural Health Study is a prospective cohort of farmers and their spouses in Iowa and North Carolina. In 2018-2019, we assessed nitrate exposure for 47 farmers who used private wells for their drinking water and lived in 8 eastern Iowa counties where groundwater is vulnerable to nitrate contamination. Drinking water and dietary intakes were estimated using the National Cancer Institute Automated Self-Administered 24-Hour Dietary Assessment tool. We measured nitrate in tap water and estimated dietary nitrate from a database of food concentrations. Urinary nitrate was measured in first morning void samples in 2018-19 and in archived samples from 2010 to 2017 (minimum time between samples: 2 years; median: 7 years). We used linear regression to evaluate urinary nitrate concentrations in relation to total nitrate, and drinking water and dietary intakes separately. Overall, dietary nitrate contributed the most to total intake (median: 97 %; interquartile range [IQR]: 57-99 %). Among 15 participants (32 %) whose drinking water nitrate concentrations were at/above the U.S. Environmental Protection Agency MCL (10 mg/L NO(3)-N), median intake from water was 44 % (IQR: 26-72 %). Total nitrate intake was the strongest predictor of urinary nitrate concentrations (R(2) = 0.53). Drinking water explained a similar proportion of the variation in nitrate excretion (R(2) = 0.52) as diet (R(2) = 0.47). Our findings demonstrate the importance of both dietary and drinking water intakes as determinants of nitrate excretion. |
CDC COVID-19 vaccination program: Healthcare provider compliance with COVID-19 vaccine requirements and recommendations
Surtees TC , Granade CJ , Wells C , Banks M , Lucas P , Graitcer SB . Vaccine 2023 The COVID-19 Vaccination Provider Oversight (CVPO) program was implemented by the Centers for Disease Control and Prevention (CDC) to ensure the proper management and administration of COVID-19 vaccines by healthcare providers participating in the CDC COVID-19 Vaccination Program. As part of the CVPO program, the 64 CDC-funded immunization program awardees conducted site visits with participating healthcare providers. We evaluated healthcare provider adherence to CVPO program requirements between May 2021 and May 2023. CVPO program site visit data was collected using a REDCap database. The proportion of site visits conducted by U.S. Department of Health and Human Services (HHS) region was calculated. Chi-square statistics for healthcare provider compliance with CVPO program requirements were presented to assess variation in compliance by provider type. The proportion of healthcare providers receiving a site visit ranged from 7.9 % to 37.2 % across HHS regions. Healthcare provider compliance was high for COVID-19 vaccine preparation, administration, and error reporting categories (>90 %). Healthcare provider compliance was lowest for vaccine storage and handling and reporting requirements (79.9 % and 82.6 %, respectively). Public health providers demonstrated significantly higher overall compliance as compared to all other included healthcare provider types (p-value < 0.05). The observed high healthcare provider compliance, coupled with thorough follow-up efforts by awardees to address any non-compliance concerns, highlights the success of jurisdictions supporting healthcare providers with proper vaccine management, administration, and safety procedures. Further research can strengthen vaccine storage, handling, and administration practices for future widespread vaccination efforts. |
2022 American College of Rheumatology Guideline for Exercise, Rehabilitation, Diet, and Additional Integrative Interventions for Rheumatoid Arthritis
England BR , Smith BJ , Baker NA , Barton JL , Oatis CA , Guyatt G , Anandarajah A , Carandang K , Chan KK , Constien D , Davidson E , Dodge CV , Bemis-Dougherty A , Everett S , Fisher N , Fraenkel L , Goodman SM , Lewis J , Menzies V , Moreland LW , Navarro-Millan I , Patterson S , Phillips LR , Shah N , Singh N , White D , AlHeresh R , Barbour KE , Bye T , Guglielmo D , Haberman R , Johnson T , Kleiner A , Lane CY , Li LC , Master H , Pinto D , Poole JL , Steinbarger K , Sztubinski D , Thoma L , Tsaltskan V , Turgunbaev M , Wells C , Turner AS , Treadwell JR . Arthritis Rheumatol 2023 75 (8) 1299-1311 OBJECTIVE: To develop initial American College of Rheumatology (ACR) guidelines on the use of exercise, rehabilitation, diet, and additional interventions in conjunction with disease-modifying antirheumatic drugs (DMARDs) as part of an integrative management approach for people with rheumatoid arthritis (RA). METHODS: An interprofessional guideline development group constructed clinically relevant Population, Intervention, Comparator, and Outcome (PICO) questions. A literature review team then completed a systematic literature review and applied the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to rate the certainty of evidence. An interprofessional Voting Panel (n = 20 participants) that included 3 individuals with RA achieved consensus on the direction (for or against) and strength (strong or conditional) of recommendations. RESULTS: The Voting Panel achieved consensus on 28 recommendations for the use of integrative interventions in conjunction with DMARDs for the management of RA. Consistent engagement in exercise received a strong recommendation. Of 27 conditional recommendations, 4 pertained to exercise, 13 to rehabilitation, 3 to diet, and 7 to additional integrative interventions. These recommendations are specific to RA management, recognizing that other medical indications and general health benefits may exist for many of these interventions. CONCLUSION: This guideline provides initial ACR recommendations on integrative interventions for the management of RA to accompany DMARD treatments. The broad range of interventions included in these recommendations illustrates the importance of an interprofessional, team-based approach to RA management. The conditional nature of most recommendations requires clinicians to engage persons with RA in shared decision-making when applying these recommendations. |
A network model analysis of an unconventional gas well breach above an underground coal mine
Dougherty H , Watkins E , Kimutis R . Min Metall Explor 2023 Gas wells have often intersected mining resources, but unconventional shale well drilling has more recently challenged mines to balance the risk of interaction due to higher pressures and larger quantities of gas. Full extraction mining, such as the longwall method, induces ground movement that may influence the casings if wells are drilled within the mining area. The possibility of a casing shear would lead to the risk of unplanned gas migration into the mine. This has the potential to quickly overcome the ventilation system and reach the explosive range which, if ignited, can have catastrophic consequences on the health and safety of underground workers. The utilization of network software to model mine ventilation is a common practice in the mining industry as a predictive tool for planning and monitoring and can assist with a well breach scenario over a large mining area. This work focuses on a well breach in between two longwall panels after second panel mining with gas entering primarily through the gobs of the adjacent longwall panels. Applying the network software Ventsim, a gob zone and ventilation network were created to better understand the distribution of gas within the mine and the limitations and effectiveness of a ventilation system. The model shows both a transient flow simulation and steady state concentrations throughout the mine ventilation system. Using a standard Pittsburgh coal seam longwall ventilation scheme, we find that the system can dilute a significant inflow of up to 700 cfm of methane. © 2023, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply. |
Improved mosquito housing and saliva collection method enhances safety while facilitating longitudinal assessment of individual mosquito vector competence for arboviruses
Ledermann JP , Burns PL , Perinet LC , Powers AM , Byers NM . Vector Borne Zoonotic Dis 2023 24 (1) 55-63 Background: Assessing the potential for mosquitoes to transmit medically important arboviruses is essential for understanding their threat to human populations. Currently, vector competence studies are typically performed by collecting saliva using a glass capillary tube system which involves sacrificing the mosquito at the time of saliva collection allowing only a single data point. These techniques also require handling infected mosquitoes and glass capillaries, constituting a safety risk. Materials and Methods: To improve the efficiency and safety of assessing vector competence, a novel containment and saliva collection approach for individually housed mosquitoes was developed. The improved housing, allowing longitudinal tracking of individual mosquitoes, consists of a 12-well Corning polystyrene plate sealed with a three-dimensional printed lid that holds organdy netting firmly against the rims of the wells. Results: This method provides excellent mosquito survival for five species of mosquitoes, with at least 79% of each species tested surviving for more than 2 weeks, comparable to the carton survival rates of ≥76%. When the plate housing system was used to assess vector infection, replication of West Nile virus (WNV) in mosquito tissues was similar to traditional containment mosquito housing. Mosquito saliva was collected using either blotting paper pads or traditional glass capillaries to assay viral transmission. The blotting paper collection showed similar or better sensitivity than the capillary method; in addition, longitudinal saliva samples could be collected from individual mosquitoes housed in the 12-well plates. Conclusions: The improved housing and saliva collection technique described herein provides a safer and more informative method for determining vector competence in mosquitoes. |
Strengthening the reporting of genetic association studies (STREGA): an extension of the strengthening the reporting of observational studies in epidemiology (STROBE) statement.
Little J , Higgins JP , Ioannidis JP , Moher D , Gagnon F , von Elm E , Khoury MJ , Cohen B , Davey-Smith G , Grimshaw J , Scheet P , Gwinn M , Williamson RE , Zou GY , Hutchings K , Johnson CY , Tait V , Wiens M , Golding J , van Duijn C , McLaughlin J , Paterson A , Wells G , Fortier I , Freedman M , Zecevic M , King R , Infante-Rivard C , Stewart AF , Birkett N . J Clin Epidemiol 2009 62 (6) 597-608.e4 Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information in the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence, the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association (STREGA) studies initiative builds on the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modeling haplotype variation, Hardy-Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data, and the volume of data issues that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed, but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct, or analysis. |
STrengthening the REporting of Genetic Association studies (STREGA): an extension of the STROBE Statement.
Little J , Higgins JP , Ioannidis JP , Moher D , Gagnon F , von Elm E , Khoury MJ , Cohen B , Davey-Smith G , Grimshaw J , Scheet P , Gwinn M , Williamson RE , Zou GY , Hutchings K , Johnson CY , Tait V , Wiens M , Golding J , van Duijn C , McLaughlin J , Paterson A , Wells G , Fortier I , Freedman M , Zecevic M , King R , Infante-Rivard C , Stewart A , Birkett N . Ann Intern Med 2009 150 (3) 206-15 Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information into the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association studies (STREGA) initiative builds on the STrengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modeling haplotype variation, Hardy-Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data, and issues of data volume that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct, or analysis. |
Strengthening the reporting of genetic association studies (STREGA): an extension of the STROBE Statement.
Little J , Higgins JP , Ioannidis JP , Moher D , Gagnon F , von Elm E , Khoury MJ , Cohen B , Davey-Smith G , Grimshaw J , Scheet P , Gwinn M , Williamson RE , Zou GY , Hutchings K , Johnson CY , Tait V , Wiens M , Golding J , van Duijn C , McLaughlin J , Paterson A , Wells G , Fortier I , Freedman M , Zecevic M , King R , Infante-Rivard C , Stewart A , Birkett N . Hum Genet 2009 125 (2) 131-51 Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information in the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association studies (STREGA) initiative builds on the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modeling haplotype variation, Hardy-Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data, and the volume of data issues that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct, or analysis. |
STrengthening the REporting of Genetic Association Studies (STREGA): an extension of the STROBE statement.
Little J , Higgins JP , Ioannidis JP , Moher D , Gagnon F , von Elm E , Khoury MJ , Cohen B , Davey-Smith G , Grimshaw J , Scheet P , Gwinn M , Williamson RE , Zou GY , Hutchings K , Johnson CY , Tait V , Wiens M , Golding J , van Duijn C , McLaughlin J , Paterson A , Wells G , Fortier I , Freedman M , Zecevic M , King R , Infante-Rivard C , Stewart A , Birkett N . PLoS Med 2009 6 (2) e22 Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information in the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association studies (STREGA) initiative builds on the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modelling haplotype variation, Hardy-Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data, and the volume of data issues that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct, or analysis. |
Strengthening the reporting of genetic association studies (STREGA): an extension of the STROBE statement.
Little J , Higgins JP , Ioannidis JP , Moher D , Gagnon F , von Elm E , Khoury MJ , Cohen B , Davey-Smith G , Grimshaw J , Scheet P , Gwinn M , Williamson RE , Zou GY , Hutchings K , Johnson CY , Tait V , Wiens M , Golding J , van Duijn C , McLaughlin J , Paterson A , Wells G , Fortier I , Freedman M , Zecevic M , King R , Infante-Rivard C , Stewart A , Birkett N . Eur J Epidemiol 2009 24 (1) 37-55 Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information in the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association studies (STREGA) initiative builds on the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modeling haplotype variation, Hardy-Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data, and the volume of data issues that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct, or analysis. |
STrengthening the REporting of Genetic Association studies (STREGA)--an extension of the STROBE statement.
Little J , Higgins JP , Ioannidis JP , Moher D , Gagnon F , von Elm E , Khoury MJ , Cohen B , Davey-Smith G , Grimshaw J , Scheet P , Gwinn M , Williamson RE , Zou GY , Hutchings K , Johnson CY , Tait V , Wiens M , Golding J , van Duijn C , McLaughlin J , Paterson A , Wells G , Fortier I , Freedman M , Zecevic M , King R , Infante-Rivard C , Stewart A , Birkett N . Eur J Clin Invest 2009 39 (4) 247-66 Making sense of rapidly evolving evidence on genetic associations is crucial to making genuine advances in human genomics and the eventual integration of this information in the practice of medicine and public health. Assessment of the strengths and weaknesses of this evidence, and hence the ability to synthesize it, has been limited by inadequate reporting of results. The STrengthening the REporting of Genetic Association studies (STREGA) initiative builds on the STrengthening the Reporting of OBservational Studies in Epidemiology (STROBE) Statement and provides additions to 12 of the 22 items on the STROBE checklist. The additions concern population stratification, genotyping errors, modelling haplotype variation, Hardy-Weinberg equilibrium, replication, selection of participants, rationale for choice of genes and variants, treatment effects in studying quantitative traits, statistical methods, relatedness, reporting of descriptive and outcome data and the volume of data issues that are important to consider in genetic association studies. The STREGA recommendations do not prescribe or dictate how a genetic association study should be designed, but seek to enhance the transparency of its reporting, regardless of choices made during design, conduct or analysis. |
Respiratory and intestinal epithelial cells exhibit differential susceptibility and innate immune responses to contemporary EV-D68 isolates (preprint)
Freeman MC , Wells AI , Ciomperlik-Patton J , Myerburg MM , Anstadt J , Coyne C . bioRxiv 2021 2021.01.05.425225 Enterovirus D68 (EV-D68) has been implicated in outbreaks of severe respiratory illness and acute flaccid myelitis (AFM) and is detected in patient respiratory samples and from stool and wastewater, suggesting both respiratory and enteric routes of transmission. Here, we used a panel of EV-D68 isolates, including a historical isolate and multiple contemporary isolates from AFM outbreak years, to define the dynamics of viral replication and the host response to infection in primary human airway cells and stem cell-derived enteroids. We show that some recent EV-D68 isolates have decreased sensitivity to acid and temperature compared with an earlier isolate and that the respiratory, but not intestinal, epithelium induces a robust type III interferon (IFN) response that restricts infection. Our findings define the differential responses of the respiratory and intestinal epithelium to contemporary EV-D68 isolates and suggest that some isolates have the potential to target both the human airway and gastrointestinal tracts.Competing Interest StatementThe authors have declared no competing interest. |
2022 American College of Rheumatology Guideline for exercise, rehabilitation, diet, and additional integrative interventions for rheumatoid arthritis
England BR , Smith BJ , Baker NA , Barton JL , Oatis CA , Guyatt G , Anandarajah A , Carandang K , Chan KK , Constien D , Davidson E , Dodge CV , Bemis-Dougherty A , Everett S , Fisher N , Fraenkel L , Goodman SM , Lewis J , Menzies V , Moreland LW , Navarro-Millan I , Patterson S , Phillips LR , Shah N , Singh N , White D , AlHeresh R , Barbour KE , Bye T , Guglielmo D , Haberman R , Johnson T , Kleiner A , Lane CY , Li LC , Master H , Pinto D , Poole JL , Steinbarger K , Sztubinski D , Thoma L , Tsaltskan V , Turgunbaev M , Wells C , Turner AS , Treadwell JR . Arthritis Care Res (Hoboken) 2023 75 (8) 1603-1615 OBJECTIVE: To develop initial American College of Rheumatology (ACR) guidelines on the use of exercise, rehabilitation, diet, and additional interventions in conjunction with disease-modifying antirheumatic drugs (DMARDs) as part of an integrative management approach for people with rheumatoid arthritis (RA). METHODS: An interprofessional guideline development group constructed clinically relevant Population, Intervention, Comparator, and Outcome (PICO) questions. A literature review team then completed a systematic literature review and applied the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to rate the certainty of evidence. An interprofessional Voting Panel (n = 20 participants) that included 3 individuals with RA achieved consensus on the direction (for or against) and strength (strong or conditional) of recommendations. RESULTS: The Voting Panel achieved consensus on 28 recommendations for the use of integrative interventions in conjunction with DMARDs for the management of RA. Consistent engagement in exercise received a strong recommendation. Of 27 conditional recommendations, 4 pertained to exercise, 13 to rehabilitation, 3 to diet, and 7 to additional integrative interventions. These recommendations are specific to RA management, recognizing that other medical indications and general health benefits may exist for many of these interventions. CONCLUSION: This guideline provides initial ACR recommendations on integrative interventions for the management of RA to accompany DMARD treatments. The broad range of interventions included in these recommendations illustrates the importance of an interprofessional, team-based approach to RA management. The conditional nature of most recommendations requires clinicians to engage persons with RA in shared decision-making when applying these recommendations. |
Large-Format Additive Manufacturing and Machining Using High-Melt-Temperature Polymers. Part I: Real-Time Particulate and Gas-Phase Emissions
Stefaniak AB , Bowers LN , Martin SB Jr , Hammond DR , Ham JE , Wells JR , Fortner AR , Knepp AK , du Preez S , Pretty JR , Roberts JL , du Plessis JL , Schmidt A , Duling MG , Bader A , Virji MA . J Chem Health Saf 2021 28 (3) 190-200 The literature on emissions during material extrusion additive manufacturing with 3-D printers is expanding; however, there is a paucity of data for large-format additive manufacturing (LFAM) machines that can extrude high-melt-temperature polymers. Emissions from two LFAM machines were monitored during extrusion of six polymers: acrylonitrile butadiene styrene (ABS), polycarbonate (PC), high-melt-temperature polysulfone (PSU), poly(ether sulfone) (PESU), polyphenylene sulfide (PPS), and Ultem (poly(ether imide)). Particle number, total volatile organic compound (TVOC), carbon monoxide (CO), and carbon dioxide (CO(2)) concentrations were monitored in real-time. Particle emission rate values (no./min) were as follows: ABS (1.7 × 10(11) to 7.7 × 10(13)), PC (5.2 × 10(11) to 3.6 × 10(13)), Ultem (5.7 × 10(12) to 3.1 × 10(13)), PPS (4.6 × 10(11) to 6.2 × 10(12)), PSU (1.5 × 10(12) to 3.4 × 10(13)), and PESU (2.0 to 5.0 × 10(13)). For print jobs where the mass of extruded polymer was known, particle yield values (g(-1) extruded) were as follows: ABS (4.5 × 10(8) to 2.9 × 10(11)), PC (1.0 × 10(9) to 1.7 × 10(11)), PSU (5.1 × 10(9) to 1.2 × 10(11)), and PESU (0.8 × 10(11) to 1.7 × 10(11)). TVOC emission yields ranged from 0.005 mg/g extruded (PESU) to 0.7 mg/g extruded (ABS). The use of wall-mounted exhaust ventilation fans was insufficient to completely remove airborne particulate and TVOC from the print room. Real-time CO monitoring was not a useful marker of particulate and TVOC emission profiles for Ultem, PPS, or PSU. Average CO(2) and particle concentrations were moderately correlated (r (s) = 0.76) for PC polymer. Extrusion of ABS, PC, and four high-melt-temperature polymers by LFAM machines released particulate and TVOC at levels that could warrant consideration of engineering controls. LFAM particle emission yields for some polymers were similar to those of common desktop-scale 3-D printers. |
Large-Format Additive Manufacturing and Machining Using High-Melt-Temperature Polymers. Part II: Characterization of Particles and Gases
Stefaniak AB , Bowers LN , Martin SB Jr , Hammond DR , Ham JE , Wells JR , Fortner AR , Knepp AK , du Preez S , Pretty JR , Roberts JL , du Plessis JL , Schmidt A , Duling MG , Bader A , Virji MA . J Chem Health Saf 2021 28 (4) 268-278 Extrusion of high-melt-temperature polymers on large-format additive manufacturing (LFAM) machines releases particles and gases, though there is no data describing their physical and chemical characteristics. Emissions from two LFAM machines were monitored during extrusion of acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) polymers as well as high-melt-temperature Ultem (poly(ether imide)), polysulfone (PSU), poly(ether sulfone) (PESU), and polyphenylene sulfide (PPS) polymers. Filter samples of particles were collected for quantification of elements and bisphenol A and S (BPA, BPS) and visualization of morphology. Individual gases were quantified on substance-specific media. Aerosol sampling demonstrated that concentrations of elements were generally low for all polymers, with a maximum of 1.6 mg/m(3) for iron during extrusion of Ultem. BPA, an endocrine disruptor, was released into air during extrusion of PC (range: 0.4 ± 0.1 to 21.3 ± 5.3 μg/m(3)). BPA and BPS (also an endocrine disruptor) were released into air during extrusion of PESU (BPA, 2.0-8.7 μg/m(3); BPS, 0.03-0.07 μg/m(3)). Work surfaces and printed parts were contaminated with BPA (<8-587 ng/100 cm(2)) and BPS (<0.22-2.5 ng/100 cm(2)). Gas-phase sampling quantified low levels of respiratory irritants (phenol, SO(2), toluene, xylenes), possible or known asthmagens (caprolactam, methyl methacrylate, 4-oxopentanal, styrene), and possible occupational carcinogens (benzene, formaldehyde, acetaldehyde) in air. Characteristics of particles and gases released by high-melt-temperature polymers during LFAM varied, which indicated the need for polymer-specific exposure and risk assessments. The presence of BPA and BPS on surfaces revealed a previously unrecognized source of dermal exposure for additive manufacturing workers using PC and PESU polymers. |
Community resources for contaminants of concern in private wells
Hubbard B , Sabogal R , Zarate-Bermudez M . J Environ Health 2023 85 (7) 36-39 In the U.S., approximately one in five water samples collected from private wells were found to be contaminated with at least one chemical at levels high enough to harm health. Given that one in eight U.S. residents obtain their water from a private well, access to safe drinking water is vital. Many private wells are not routinely tested for contaminants, which can be microbiological, chemical, or radiological. Environmental health practitioners serve as a valuable resource, helping their communities to increase well testing, identify contaminants of concern, and understand well water testing results. This month’s column highlights the work of the Centers for Disease Control and Prevention to improve drinking water in private wells. |
Feasibility of a selective epoxidation technique for use in quantification of peracetic acid in air samples collected on sorbent tubes
Walsh CM , Jackson SR , Baughman NN , Ham JE , Wells JR . J Chem Health Saf 2022 29 (4) 378-386 Peracetic acid is a disinfection agent used in medical and food processing facilities, and occupational exposures have been documented. To facilitate characterization of daily occupational exposures, the current work describes the development of a personal sampling technique to quantify the peracetic acid concentration in air samples. Peracetic acid atmospheres were generated in 100 L Teflon chambers, and samples were collected on 350 mg XAD-7 solid sorbent tubes for 4 h at a flow rate of 250 mL/min using a personal sampling pump. Indirect measurement of peracetic acid was achieved by desorption from the sorbent and subsequent treatment with cyclohexene to initiate an epoxidation reaction, formally known as the Prilezhaev reaction. The epoxidation product, cyclohexene oxide, was quantified by gas chromatography-mass spectrometry. The reaction enabled quantification of peracetic acid with high specificity over the common co-contaminants hydrogen peroxide and acetic acid, which were introduced in 10-fold and 100-fold excess to challenge the reaction. The technique also demonstrated an overall estimate of bias and precision of 11 and 8%, respectively, and a limit of detection of 60 ppbv was estimated. Preliminary storage experiments indicate that unreacted peracetic acid is stable on the sorbent tubes for 72 h when stored at -20 °C following collection. Overall, the specificity of the reaction and capability to sample for longer time periods than current methods, in addition to the use of safer personal sampling materials, demonstrate the utility of this technique for peracetic acid measurement in air. © 2022 Elsevier Inc.. All rights reserved. |
Dialysis Water Supply Faucet as Reservoir for Carbapenemase-Producing Pseudomonas aeruginosa
Prestel C , Moulton-Meissner H , Gable P , Stanton RA , Glowicz J , Franco L , McConnell M , Torres T , John D , Blackwell G , Yates R , Brown C , Reyes K , McAllister GA , Kunz J , Conners EE , Benedict KM , Kirby A , Mattioli M , Xu K , Gualandi N , Booth S , Novosad S , Arduino M , Halpin AL , Wells K , Walters MS . Emerg Infect Dis 2022 28 (10) 2069-2073 During June 2017-November 2019, a total 36 patients with carbapenem-resistant Pseudomonas aeruginosa harboring Verona-integron-encoded metallo-β-lactamase were identified in a city in western Texas, USA. A faucet contaminated with the organism, identified through environmental sampling, in a specialty care room was the likely source for infection in a subset of patients. |
MaHPIC malaria systems biology data from Plasmodium cynomolgi sporozoite longitudinal infections in macaques.
DeBarry JD , Nural MV , Pakala SB , Nayak V , Warrenfeltz S , Humphrey J , Lapp SA , Cabrera-Mora M , Brito CFA , Jiang J , Saney CL , Hankus A , Stealey HM , DeBarry MB , Lackman N , Legall N , Lee K , Tang Y , Gupta A , Trippe ED , Bridger RR , Weatherly DB , Peterson MS , Jiang X , Tran V , Uppal K , Fonseca LL , Joyner CJ , Karpuzoglu E , Cordy RJ , Meyer EVS , Wells LL , Ory DS , Lee FE , Tirouvanziam R , Gutiérrez JB , Ibegbu C , Lamb TJ , Pohl J , Pruett ST , Jones DP , Styczynski MP , Voit EO , Moreno A , Galinski MR , Kissinger JC . Sci Data 2022 9 (1) 722 Plasmodium cynomolgi causes zoonotic malarial infections in Southeast Asia and this parasite species is important as a model for Plasmodium vivax and Plasmodium ovale. Each of these species produces hypnozoites in the liver, which can cause relapsing infections in the blood. Here we present methods and data generated from iterative longitudinal systems biology infection experiments designed and performed by the Malaria Host-Pathogen Interaction Center (MaHPIC) to delve deeper into the biology, pathogenesis, and immune responses of P. cynomolgi in the Macaca mulatta host. Infections were initiated by sporozoite inoculation. Blood and bone marrow samples were collected at defined timepoints for biological and computational experiments and integrative analyses revolving around primary illness, relapse illness, and subsequent disease and immune response patterns. Parasitological, clinical, haematological, immune response, and -omic datasets (transcriptomics, proteomics, metabolomics, and lipidomics) including metadata and computational results have been deposited in public repositories. The scope and depth of these datasets are unprecedented in studies of malaria, and they are projected to be a F.A.I.R., reliable data resource for decades. |
Evaluating vacant middle seats and masks as Coronavirus exposure reduction strategies in aircraft cabins using particle tracer experiments and computational fluid dynamics simulations.
Bennett JS , Mahmoud S , Dietrich W , Jones B , Hosni M . Eng Rep 2022 e12582 Aircraft cabins have high-performance ventilation systems, yet typically hold many persons in close proximity for long durations. The current study estimated airborne virus exposure and infection reductions when middle seats are vacant compared to full occupancy and when passengers wear surgical masks in aircraft. Tracer particle data reported by U.S. Transportation Command (TRANSCOM) and CFD simulations reported by Boeing were used along with NIOSH data, to build nonlinear regression models with particle exposure and distance from particle source as variables. These models that estimate exposure at given distances from the viral source were applied to evaluate exposure reductions from vacant middle seats. Reductions averaged 54% for the seat row where an infectious passenger is located and 36% for a 24-row cabin containing one infectious passenger, with middle seats vacant. Analysis of the TRANSCOM data showed that universal masking (surgical masks) reduced exposures by 62% and showed masking and physical distancing provide further reductions when practiced together. For a notional scenario involving 10 infectious passengers, compared with no intervention, masking, distancing, and both would prevent 6.2, 3.8, and 7.6 secondary infections, respectively, using the Wells–Riley equation. These results suggest distancing alone, masking alone, and these practiced together reduce SARS CoV-2 exposure risk in increasing order of effectiveness, when an infectious passenger is present. © 2022 The Authors. Engineering Reports published by John Wiley & Sons Ltd. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. |
Keep your water safe with resources from the Centers for Disease Control and Prevention
Curtiss E , Hils J , Rokisky JJr . J Environ Health 2022 84 (10) 42-43 People in the U.S. have access to some | of the safest public drinking water supplies in the world (Centers for Disease | Control and Prevention [CDC], 2021a). Environmental health professionals are one of | the key groups that help make drinking water safe. They also help make water safe for | communities that depend on private wells, | residents in buildings with complex water systems, and swimmers who exercise regularly in | pools. The Water, Food, and Environmental | Health Services Branch (WFEHSB) within the | Centers for Disease Control and Prevention | (CDC) supports environmental health professionals with tools and resources to strengthen | safe water for community health (Table 1) |
Rockmass permeability induced by longwall mining under deep cover: Potential gas inflow from a sheared gas well
Khademian Z , Ajayi KM , Schatzel SJ , Esterhuizen GS , Kim BH . Min Metall Explor 2022 39 (4) 1465-1473 The stability of shale gas wells drilled through current and future coal reserves can be compromised by ground deformations due to nearby longwall mining. Depending on the longwall-induced rockmass permeability, the high-pressure explosive gas from the damaged well may reach mine workings and overwhelm the mine ventilation systems. This study uses geomechanical models to estimate the rockmass permeability induced by mining. A two-panel longwall model of a deep, 341-m-cover mining site in southwestern Pennsylvania is constructed in 3DEC to explicitly model the rockmass by a discrete fracture network (DFN) technique. Stress-induced fracture apertures and permeabilities are calculated across the model and are validated against permeability measurements. A fracture flow code (FFC) is developed to use these results to predict potential inflow to the mine should a gas well breach occur. One hundred DFN realizations are simulated, and the results show that for a gas pressure of 2.4 MPa, the average of the predicted inflow rates to this deep-cover mine is 0.006 m3/s, significantly lower than the average inflow of 0.22 m3/s for a shallow-cover mine (145-m deep) studied in the previous work (Khademian, et al. 2021). The result can help assess the potential hazards of a shale gas well breach for mine safety and evaluate the ventilation requirements to mitigate the risk. © 2022, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply. |
Identifying longwall-induced fracture zone height through core drilling
Van Dyke MA , Zhang P , Dougherty H , Su D , Kim BH . Min Metall Explor 2022 39 (4) 1345-1355 The National Institute for Occupational Safety and Health (NIOSH) has been evaluating longwall mining-induced strata fractures and their impacts on casing stability of Marcellus shale gas wells located in longwall pillars. To understand the extent of overburden fractures after longwall mining, NIOSH researchers drilled a post-mining corehole into the fractured strata above the Pittsburgh coal seam longwall gob. Knowing the extent of the fracture zone height will help gas operators minimize the hazards of drilling into longwall gobs. The core was retrieved from the surface down to the top of the gob void. Various fractures were encountered varying from 35 to 64°, depending on lithologic type and relative closeness to the gob. The longwall panel dimension was 457-m wide and 3657-m long, in which the total fracture zone height was found to be at 141 m and the hydraulic connected fracture zone at 87.7 m above the top of the Pittsburgh seam. In addition to core drilling through the gob, FLAC3D modeling was also used to simulate the formation of fracture zone and the orientations of longwall-induced fractures. This study provides much-needed evidence on the fracture zone of Pittsburgh seam longwall gobs to help gas operators avoid potential hazards associated with drilling through highly fractured zones in longwall gobs. © 2022, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply. |
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