scholarly journals Influencing Trend and Extent of Combined Exposure Levels of Total Arsenic and Inorganic Arsenic on Arsenic Methylation Capacity Among University Students: Findings from Bayesian Analysis Using Kernel Machine Regression

2021 ◽  
Author(s):  
Rui Jiang ◽  
Qing Zhang ◽  
Dongmei Ji ◽  
Tingting Jiang ◽  
Yuan Hu ◽  
...  
Keyword(s):  
University Students ◽  
Inorganic Arsenic ◽  
Exposure Level ◽  
Combined Exposure ◽  
Single Exposure ◽  
Specific Level ◽  
Kernel Machine ◽  
Methylation Capacity ◽  
Kernel Machine Regression ◽  
Exposure Levels

Abstract The arsenic (As) methylation capacity is an important determinant of the susceptibility to arsenic-related diseases. Total As (TAs) or inorganic As (iAs) was reported to associate with As methylation capacity individually, however, influencing trend and extent of their combined exposure levels on methylation capacity remains poorly understood. We measured urinary concentrations of iAs, monomethylarsonic (MMA), and dimethylarsinic (DMA) acids using HPLC-HG-AFS, and calculated the primary (PMI: (MMA+DMA)/TAs) and secondary (SMI: DMA/(MMA+DMA)) methylation capacity indexes in 209 university students in Hefei, China, a non-As endemic area. Subjects were given with a standardized questionnaire to inquire their sociodemographic characteristics. Bayesian kernal machine regression (BKMR) analysis was used to estimate the association of lnTAs and lniAs levels with methylation indices (ln%MMA, ln%DMA, lnPMI, lnSMI). The median concentration of iAs, MMA and DMA was 1.22, 0.92 and 12.17 μg/L, respectively; the proportions of iAs, MMA and DMA were 8.76%, 6.13% and 84.84%, respectively. Females had higher %DMA and lower %MMA, while males had lower %DMA and higher %MMA. The combined levels of lnTAs and lniAs showed monotonic decrease in change of ln%DMA and lnSMI other than ln%MMA, additionally, change in ln%PMI was decreased only when levels of lnTAs and lniAs were larger than their 60th percentiles compared to they were at 50th percentile. With regard to single exposure level, the lnTAs showed positive correlation with ln%DMA, lnPMI, lnSMI when lniAs was set at a specific level; while lniAs showed negative correlation with ln%DMA, lnPMI, lnSMI when lnTAs was set at a specific level; and all the dose-response relationships were nonlinear. Our results suggested that combined levels of TAs and iAs played an important role in reducing As methylation capacity, expecially iAs; and the reduction only occured when TAs and iAs were up to a certain combined level.

scholarly journals Repeated Noise Exposure Does Not Reach Hazardous Levels During Total Joint Arthroplasty

2020 ◽  
Vol 185 (9-10) ◽  
pp. e1551-e1555
Author(s):  
Sean E Slaven ◽  
Benjamin M Wheatley ◽  
Daniel L Christensen ◽  
Sameer K Saxena ◽  
Robert J McGill
Keyword(s):  
Noise Exposure ◽  
Weighted Average ◽  
Sound Level ◽  
Health Concern ◽  
Exposure Level ◽  
Total Knee ◽  
Time Weighted Average ◽  
Exposure Levels ◽  
Occupational Standards ◽  
Level Meter

Abstract Introduction Noise exposure is an occupational health concern for certain professions, especially military servicemembers and those using power tools on a regular basis. The purpose of this study was to quantify noise exposure during total hip arthroplasty (THA) and total knee arthroplasty (TKA) cases compared to the recommended standard for occupational noise exposure. Materials and Methods A sound level meter was used to record cumulative and peak noise exposure levels in 10 primary THA and 10 primary TKA surgeries, as well as 10 arthroscopy cases as controls. Measurements at the distance of the surgeon were taken in all cases. In TKA cases, measurements were taken at 3 feet and 8 feet from the surgeon, to simulate the position of the anesthetist and circulating nurse, respectively. Results Time-weighted average was significantly higher in THA (64.7 ± 5.2 dB) and TKA (64.5 ± 6.8 dB) as compared to arthroscopic cases (51.1 ± 7.5 dB, P < 0.001) and higher at the distance of the surgeon (64.5 ± 6.8 dB) compared to the anesthetist (52.9 ± 3.8 dB) and the circulating nurse (54.8 ± 11.2 dB, P = 0.006). However, time-weighted average was below the recommended exposure level of 85 dB for all arthroplasty cases. Peak levels did not differ significantly between surgery type or staff role, and no values above the ceiling limit of 140 dB were recorded. Surgeon’s daily noise dose percentage per case was 1.78% for THA and 2.04% for TKA. Conclusion Noise exposure in THA and TKA was higher than arthroscopic cases but did not exceed occupational standards. A daily dose percentage of approximately 2% per case indicates that repeated noise exposure likely does not reach hazardous levels in modern arthroplasty practice.

scholarly journals Evaluación de niveles de exposición electromagnética causados por las estaciones base de Telefonía Móvil Celular [Assessment for electromagnetic exposure level caused by cellular mobile transmitting antennas in base station]

2014 ◽  
Author(s):  
Walder de Jesús Canova García
Keyword(s):  
Electromagnetic Field ◽  
Base Station ◽  
Base Stations ◽  
Exposure Level ◽  
Field Exposure ◽  
Palabras Clave ◽  
Exposure Levels ◽  
Mobile Base Station ◽  
Cellular Mobile ◽  
Mobile Base

Resumen El creciente número de estaciones base de telefonía móvil celular alrededor de sectores residenciales o tránsito de personas, causa preocupación en la comunidad sobre si la radiación de campos electromagnéticos puedan causar riesgos en la salud. Internacionalmente existen estándares que establecen límites a las diversas fuentes de campos electromagnéticos para garantizar que se minimizan los riesgos en la salud. Cada país adopta dentro de su legislación algún estándar o recomendación y exige su cumplimiento a los operadores de estaciones de telecomunicaciones, por ejemplo en Colombia rige el decreto 195 de 2005. El artículo presenta una evaluación, basados en mediciones técnicas en el 2010, para obtener los niveles de exposición a campos electromagnéticos generados por las antenas instaladas en las estaciones base de telefonía móvil. Luego aparece el procedimiento general de mediciones, donde incluye el plan ejecutorial de mediciones, la configuración de la instrumentación y la caracterización de los lugares y puntos de medición. Por último, los resultados medidos en algunos lugares, donde las antenas de transmisión cumplían con la normativa adoptada en Colombia. Palabras Clave: Exposición a campos Electromagnéticos, Estaciones base de Telefonía móvil celular, Mediciones de banda angosta.   Abstract The growth of installations of transmitting antennas on base stations surrounding residential spaces or person traffic causes concerns in the community, about whether the radiation of electromagnetic fields of transmitting antennas in mobile base station can generate health risk. Over the world, there are standards that establish maximum levels permitted to different electromagnetic field sources to accomplish security ranges for health risks. Each country adopts in their legislation some international standard and requires to telecommunication operators stations for its compliance. In Colombian, the decree 195 of 2005 is still valid. This article shows an assessment, based on technical measurements developed in 2010, to acquire the electromagnetic field exposure levels generated by transmitting antennas installed on Mobile Base Station. This assessment includes the measurement system procedure: plan of measurement, instrumental configuration, and characterization of measurement places. Finally, here presents the measured results in some places, which exposure levels satisfied the adopted legislation in Colombia. Keywords: Electromagnetic Field Exposure, Mobile Base Stations, Narrowband Measurement.

scholarly journals Modeling the health effects of time-varying complex environmental mixtures: Mean field variational Bayes for lagged kernel machine regression

2018 ◽  
Vol 29 (4) ◽  
pp. e2504 ◽  
Author(s):  
Shelley H. Liu ◽  
Jennifer F. Bobb ◽  
Birgit Claus Henn ◽  
Lourdes Schnaas ◽  
Martha M. Tellez-Rojo ◽  
...  
Keyword(s):  
Health Effects ◽  
Mean Field ◽  
Variational Bayes ◽  
Time Varying ◽  
Kernel Machine ◽  
Kernel Machine Regression ◽  
Environmental Mixtures

Abstract 077: In Utero Exposure To Metal Mixtures And Offspring Blood Pressure: An Analysis Of The Boston Birth Cohort Using Bayesian Kernel Machine Regression

Circulation ◽  
2021 ◽  
Vol 143 (Suppl_1) ◽  
Author(s):  
Mingyu Zhang ◽  
Tiange Liu ◽  
Guoying Wang ◽  
Jessie P Buckley ◽  
Eliseo Guallar ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Birth Cohort ◽  
In Utero ◽  
Linear Regression Models ◽  
Metal Mixtures ◽  
Kernel Machine ◽  
American Academy Of Pediatrics ◽  
Kernel Machine Regression ◽  
The Individual ◽  
Antioxidant Effects

Background: In utero exposure to metals lead (Pb), cadmium (Cd), and mercury (Hg) may be associated with higher childhood systolic blood pressure (SBP), while trace elements manganese (Mn) and selenium (Se) may have protective, antioxidant effects that modify metal-SBP associations. No study has examined how in utero co-exposure to these metals affect offspring SBP. Objectives: To examine the individual and joint effects of in utero exposure to Cd, Pb, Hg, Mn, and Se on offspring SBP. Methods: We used data from the Boston Birth Cohort (enrolled 2002-2013). We measured metals in maternal red blood cells collected 24-72 hours after delivery. We calculated child age-, sex-, and height-specific SBP percentile per 2017 American Academy of Pediatrics guidelines. We used linear regression models to estimate associations of each metal, and Bayesian kernel machine regression (BKMR) to examine metal co-exposures, with child SBP between 3 to 15 years of age. Results: Our analytic sample comprised 1194 mother-child pairs (61% Black, 20% Hispanic). Hg and Pb were not associated with child SBP. Se and Mn were inversely associated with child SBP: each log2(Se) and log2(Mn) increment was associated with a 6.23 (95% CI: 0.96-11.51) and a 2.62 (95% CI: 0.04-5.20) percentile lower child SBP, respectively. BKMR models showed similar results ( Panel A ). While Cd was not overall associated with child SBP, there was an antagonistic interaction between Cd and Mn (P-interaction = 0.036): the association of Mn and lower child SBP was stronger with higher levels of Cd ( Panel B ). Consistent with this finding, in utero exposure to cigarette smoke (a major source of Cd) modified the association of Mn and child SBP: among children born mothers who smoked cigarette in pregnancy, each log2(Mn) increment was associated with a 10.09 (95% CI: 2.15-18.03) percentile lower SBP ( Panel C ). Conclusion: Optimizing in utero Se levels, as well as Mn levels in pregnant women who had high Cd or smoked during pregnancy, may protect offspring from developing high BP during childhood.

METHODOLOGICAL FOUNDATIONS FOR SUBSTANTIATING SAFE LEVELS OF EXPOSURE TO ARTIFICIAL NANOMATERIALS (FOR EXAMPLE, CARBON NANOTUBES)

2021 ◽  
Author(s):  
G.A. Timerbulatova ◽  
◽  
Keyword(s):  
Carbon Nanotubes ◽  
Harmful Effect ◽  
Exposure Level ◽  
In Vivo Experiments ◽  
World Markets ◽  
Dose Concentration ◽  
Exposure Levels ◽  
Planning Of Experiments

Abstract: The unique physicochemical properties of carbon nanotubes allow them to be used in many fields. The global nanomaterials market is growing every year. An important step in introducing products to the domestic and world markets is to determine the safe exposure levels of CNTs. Establishing a corporate standard can serve as a preliminary stage before the approval of a state hygiene standard. Justification of the corporate standard is carried out in in vitro and in vivo experiments. The planning of experiments should be carried out taking into account the target organ under the influence of CNT - the respiratory system. The recommended dose / concentration range for experiments should include doses / concentrations derived from calculated and literature data. A necessary step is to obtain homogeneous dispersions in which CNTs become bioavailable for biological systems. During in vitro and in vivo experiments, the exposure level is determined at which no harmful effect is observed and / or the lowest level of exposure at which there is a harmful effect on the cell culture / respiratory tract of animals.

scholarly journals Occupational exposure and markers of genetic damage, systemic inflammation and lung function: a Danish cross-sectional study among air force personnel

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria Helena Guerra Andersen ◽  
Anne Thoustrup Saber ◽  
Marie Frederiksen ◽  
Per Axel Clausen ◽  
Camilla Sandal Sejbaek ◽  
...  
Keyword(s):  
Occupational Exposure ◽  
Lung Function ◽  
Air Force ◽  
Systemic Inflammation ◽  
Reference Group ◽  
Exposed Group ◽  
Exposure Level ◽  
Genetic Damage ◽  
Job Functions ◽  
Exposure Levels

AbstractAir force ground crew personnel are potentially exposed to fuels and lubricants, as raw materials, vapours and combustion exhaust emissions, during operation and maintenance of aircrafts. This study investigated exposure levels and biomarkers of effects for employees at a Danish air force military base. We enrolled self-reported healthy and non-smoking employees (n = 79) and grouped them by exposure based on job function, considered to be potentially exposed (aircraft engineers, crew chiefs, fuel operators and munition specialists) or as reference group with minimal occupational exposure (avionics and office workers). We measured exposure levels to polycyclic aromatic hydrocarbons (PAHs) and organophosphate esters (OPEs) by silicone bands and skin wipes (PAHs only) as well as urinary excretion of PAH metabolites (OH-PAHs). Additionally, we assessed exposure levels of ultrafine particles (UFPs) in the breathing zone for specific job functions. As biomarkers of effect, we assessed lung function, plasma levels of acute phase inflammatory markers, and genetic damage levels in peripheral blood cells. Exposure levels of total PAHs, OPEs and OH-PAHs did not differ between exposure groups or job functions, with low correlations between PAHs in different matrices. Among the measured job functions, the UFP levels were higher for the crew chiefs. The exposure level of the PAH fluorene was significantly higher for the exposed group than the reference group (15.9 ± 23.7 ng/g per 24 h vs 5.28 ± 7.87 ng/g per 24 h, p = 0.007), as was the OPE triphenyl phosphate (305 ± 606 vs 19.7 ± 33.8 ng/g per 24 h, p = 0.011). The OPE tris(1,3-dichlor-2-propyl)phosphate had a higher mean in the exposed group (60.7 ± 135 ng/g per 24 h) compared to the reference group (8.89 ± 15.7 ng/g per 24 h) but did not reach significance. No evidence of effects for biomarkers of systemic inflammation, genetic damage or lung function was found. Overall, our biomonitoring study show limited evidence of occupational exposure of air force ground crew personnel to UFPs, PAHs and OPEs. Furthermore, the OH-PAHs and the assessed biomarkers of early biological effects did not differ between exposed and reference groups.

scholarly journals Ecotoxicological Effect of Single and Combined Exposure of Carbamazepine and Cadmium on Female Danio rerio: A Multibiomarker Study

2019 ◽  
Vol 9 (7) ◽  
pp. 1362 ◽  
Author(s):  
Chunhong Shi ◽  
Yide He ◽  
Jiaxin Liu ◽  
Yue Lu ◽  
Yuting Fan ◽  
...  
Keyword(s):  
Endocrine Disruption ◽  
Danio Rerio ◽  
Antioxidant Systems ◽  
Aquatic Environments ◽  
Toxicity Profile ◽  
Combined Exposure ◽  
Single Exposure ◽  
Aquatic Vertebrates ◽  
Ecotoxicological Effect ◽  
Environmental Relevance

In aquatic environments, organisms are exposed to mixtures of pollutants which may change the toxicity profile of each contaminant, compared to its toxicity alone. Carbamazepine (CBZ) and cadmium (Cd) are among the pollutants that co-occur in aquatic environments. To date, most research about their toxicity towards aquatic vertebrates is based on single exposure experiments. The present study aims to evaluate single and combined effects of CBZ and Cd on biomarkers in female Danio rerio (zebrafish) by exposing them to environmentally relevant concentrations of these two pollutants for ten days. Four kinds of biomarkers involved in antioxidant systems, energy metabolism, nervous system, and endocrine disruption, respectively, were studied. Our research results coincided with those of former studies in single exposure experiments. However, the combined exposure of CBZ and Cd exerted different responses from other studies in which these two contaminants were examined alone in zebrafish. The present study evidenced the need to conduct more coexposure studies to enhance the environmental relevance of these experimental results.

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