Sample records for facepiece particulate respirator

  1. Disclosure and Fit Capability of the Filtering Facepiece Respirator.

    PubMed

    Lofgren, Don J

    2018-05-01

    The filtering facepiece air-purifying respirator is annually purchased in the tens of millions and widely used for worker protection from harmful airborne particulates. The workplace consumers of this safety product, i.e., employers, workers, and safety and health professionals, have assurances of its effectiveness through the respirator certification and disclosure requirements of the National Institute for Occupational Safety and Health. However, the certification of a critical performance requirement has been missing for the approved filtering facepiece respirator since 1995: fit capability. Without this certification, consumers continue to be at risk of purchasing a respirator model that may fit a small percentage of the intended users. This commentary updates and expands an earlier one by this author, addresses the consequences of poorly fitting certified models on the market and lack of disclosure, and calls for further action by National Institute for Occupational Safety and Health to meet the needs and expectations of the consumer.

  2. Field performance measurements of half-facepiece respirators: steel mill operations.

    PubMed

    Myers, W R; Zhuang, Z

    1998-11-01

    Ambient and in-facepiece samples to evaluate the protection provided by negative-pressure, half-facepiece respirators were collected on workers in different areas of a steel mill including a sinter plant and a basic oxygen process shop. Protection was assessed by workplace protection factors (WPF). All the in-facepiece concentrations were dramatically less than the corresponding ambient concentration levels or permissible exposure limits. The geometric mean (GM) ambient and in-facepiece concentrations of iron were found to vary among tasks. Significant differences were also found to occur between the GM ambient exposure levels in which some of the respirators were used. Significant differences in respirator performance as measured by WPF or in-facepiece iron concentration were observed among different brands of respirators. For all job classifications and at all levels of airborne exposure, the fifth percentile estimates for the WPF distributions for each brand of respirator were all greater than 20.

  3. Transfer of bacteriophage MS2 and fluorescein from N95 filtering facepiece respirators to hands: Measuring fomite potential

    PubMed Central

    Brady, Tyler M.; Strauch, Amanda L.; Almaguer, Claudia M.; Niezgoda, George; Shafer, Ronald E.; Yorio, Patrick L.; Fisher, Edward M.

    2017-01-01

    Contact transmission of pathogens from personal protective equipment is a concern within the healthcare industry. During public health emergency outbreaks, resources become constrained and the reuse of personal protective equipment, such as N95 filtering facepiece respirators, may be needed. This study was designed to characterize the transfer of bacteriophage MS2 and fluorescein between filtering facepiece respirators and the wearer’s hands during three simulated use scenarios. Filtering facepiece respirators were contaminated with MS2 and fluorescein in droplets or droplet nuclei. Thirteen test subjects performed filtering facepiece respirator use scenarios including improper doffing, proper doffing and reuse, and improper doffing and reuse. Fluorescein and MS2 contamination transfer were quantified. The average MS2 transfer from filtering facepiece respirators to the subjects’ hands ranged from 7.6–15.4% and 2.2–2.7% for droplet and droplet nuclei derived contamination, respectively. Handling filtering facepiece respirators contaminated with droplets resulted in higher levels of MS2 transfer compared to droplet nuclei for all use scenarios (p = 0.007). MS2 transfer from droplet contaminated filtering facepiece respirators during improper doffing and reuse was greater than transfer during improper doffing (p = 0.008) and proper doffing and reuse (p = 0.042). Droplet contamination resulted in higher levels of fluorescein transfer compared to droplet nuclei contaminated filtering facepiece respirators for all use scenarios (p = 0.009). Fluorescein transfer was greater for improper doffing and reuse (p = 0.007) from droplet contaminated masks compared to droplet nuclei contaminated filtering facepiece respirators and for improper doffing and reuse when compared improper doffing (p = 0.017) and proper doffing and reuse (p = 0.018) for droplet contaminated filtering facepiece respirators. For droplet nuclei contaminated filtering facepiece respirators, the

  4. Comparison of two quantitative fit-test methods using N95 filtering facepiece respirators.

    PubMed

    Sietsema, Margaret; Brosseau, Lisa M

    2016-08-01

    Current regulations require annual fit testing before an employee can wear a respirator during work activities. The goal of this research is to determine whether respirator fit measured with two TSI Portacount instruments simultaneously sampling ambient particle concentrations inside and outside of the respirator facepiece is similar to fit measured during an ambient aerosol condensation nuclei counter quantitative fit test. Sixteen subjects (ten female; six male) were recruited for a range of facial sizes. Each subject donned an N95 filtering facepiece respirator, completed two fit tests in random order (ambient aerosol condensation nuclei counter quantitative fit test and two-instrument real-time fit test) without removing or adjusting the respirator between tests. Fit tests were compared using Spearman's rank correlation coefficients. The real-time two-instrument method fit factors were similar to those measured with the single-instrument quantitative fit test. The first four exercises were highly correlated (r > 0.7) between the two protocols. Respirator fit was altered during the talking or grimace exercise, both of which involve facial movements that could dislodge the facepiece. Our analyses suggest that the new real-time two-instrument methodology can be used in future studies to evaluate fit before and during work activities.

  5. Effect of exhaled moisture on breathing resistance of N95 filtering facepiece respirators.

    PubMed

    Roberge, Raymond J; Bayer, Emily; Powell, Jeffrey B; Coca, Aitor; Roberge, Marc R; Benson, Stacey M

    2010-08-01

    This study evaluated the effect of exhaled moisture on the breathing resistance of three classes of filtering facepiece respirators (FFR) following 4 h of continuous wear at a breathing volume of 40 l min(-1), utilizing an automated breathing and metabolic simulator as a human surrogate. After 4 h, inhalation and exhalation resistance increased by 0.43 and 0.23 mm of H(2)O pressure, respectively, and average moisture retention in the respirators was 0.26 ml. Under ambient conditions similar to those of the current study, and at similar breathing volumes, it is unlikely that exhaled moisture will add significantly to the breathing resistance of filtering facepiece respirators (FFR) over 4 h of use.

  6. 21 CFR 880.6260 - Filtering facepiece respirator for use by the general public in public health medical emergencies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... general public in public health medical emergencies. 880.6260 Section 880.6260 Food and Drugs FOOD AND... Filtering facepiece respirator for use by the general public in public health medical emergencies. (a) Identification. A filtering facepiece respirator for use by the general public in public health medical...

  7. 21 CFR 880.6260 - Filtering facepiece respirator for use by the general public in public health medical emergencies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... general public in public health medical emergencies. 880.6260 Section 880.6260 Food and Drugs FOOD AND... Filtering facepiece respirator for use by the general public in public health medical emergencies. (a) Identification. A filtering facepiece respirator for use by the general public in public health medical...

  8. 21 CFR 880.6260 - Filtering facepiece respirator for use by the general public in public health medical emergencies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... general public in public health medical emergencies. 880.6260 Section 880.6260 Food and Drugs FOOD AND... Filtering facepiece respirator for use by the general public in public health medical emergencies. (a) Identification. A filtering facepiece respirator for use by the general public in public health medical...

  9. 21 CFR 880.6260 - Filtering facepiece respirator for use by the general public in public health medical emergencies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... general public in public health medical emergencies. 880.6260 Section 880.6260 Food and Drugs FOOD AND... Filtering facepiece respirator for use by the general public in public health medical emergencies. (a) Identification. A filtering facepiece respirator for use by the general public in public health medical...

  10. 21 CFR 880.6260 - Filtering facepiece respirator for use by the general public in public health medical emergencies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... general public in public health medical emergencies. 880.6260 Section 880.6260 Food and Drugs FOOD AND... Filtering facepiece respirator for use by the general public in public health medical emergencies. (a) Identification. A filtering facepiece respirator for use by the general public in public health medical...

  11. Evaluation of particulate filtering respirators using inward leakage (IL) or total inward leakage (TIL) testing--Korean experience.

    PubMed

    Han, Don-Hee; Lee, Jinheon

    2005-10-01

    Korean certification regulation for particulate filtering respirators requires inward leakage (IL) or total inward leakage (TIL) testing according to European Standard EN 13274-1, and the standard levels of compliance are similar to those of the European Standard. This study was conducted to evaluate particulate filtering respirators being commercially used in the Korean market using an IL or TIL test and the validity of standard level in Korea. Three half masks and 10 filtering facepieces (two top class, four 1st class and four 2nd class)-a total of 13 brand name respirators-were selected for the test with panels of 10 subjects. Each subject was classified with nine facial dimension grid squares in accordance with face length and lip length. IL or TIL testing was conducted at the laboratory of the 3M Innovation Center in which the experimental instruments and systems were established in compliance with European standards. The testing procedure followed EN 13274-1 (2001). As expected, leakages of half masks were less than those of filtering facepieces and the latter were significantly different among brands. TILs of the 1st class filtering facepieces were found to be much more than those of the 2nd class and the result may cause a wearer to get confused when selecting a mask. The main route leakage for filtering facepieces may not be the filter medium but the face seal. Therefore, it is necessary to develop well-fitting filtering facepieces for Koreans. Because leakages were significantly different for different facial dimensions, a defined test panel for IL or TIL testing according to country or race should be developed. A more precise method to demonstrate fit, for example, fit testing such as in the US regulations, will be needed before IL or TIL testing or when selecting a respirator. Another finding implies that geometric mean of five exercises for IL or TIL may be better than arithmetic mean to establish a standard individual subject mean.

  12. 42 CFR 84.135 - Half-mask facepieces, full facepieces, hoods, and helmets; fit; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Half-mask facepieces, full facepieces, hoods, and... OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.135 Half-mask facepieces, full facepieces, hoods, and helmets; fit; minimum requirements. (a) Half-mask facepieces and full facepieces shall...

  13. 42 CFR 84.198 - Half-mask facepieces, full facepieces, mouthpieces, hoods, and helmets; fit; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Half-mask facepieces, full facepieces, mouthpieces... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.198 Half-mask facepieces, full facepieces, mouthpieces, hoods, and helmets; fit; minimum requirements. (a) Half-mask facepieces...

  14. Nanoparticle filtration performance of NIOSH-certified particulate air-purifying filtering facepiece respirators: evaluation by light scattering photometric and particle number-based test methods.

    PubMed

    Rengasamy, Samy; Eimer, Benjamin C

    2012-01-01

    National Institute for Occupational Safety and Health (NIOSH) certification test methods employ charge neutralized NaCl or dioctyl phthalate (DOP) aerosols to measure filter penetration levels of air-purifying particulate respirators photometrically using a TSI 8130 automated filter tester at 85 L/min. A previous study in our laboratory found that widely different filter penetration levels were measured for nanoparticles depending on whether a particle number (count)-based detector or a photometric detector was used. The purpose of this study was to better understand the influence of key test parameters, including filter media type, challenge aerosol size range, and detector system. Initial penetration levels for 17 models of NIOSH-approved N-, R-, and P-series filtering facepiece respirators were measured using the TSI 8130 photometric method and compared with the particle number-based penetration (obtained using two ultrafine condensation particle counters) for the same challenge aerosols generated by the TSI 8130. In general, the penetration obtained by the photometric method was less than the penetration obtained with the number-based method. Filter penetration was also measured for ambient room aerosols. Penetration measured by the TSI 8130 photometric method was lower than the number-based ambient aerosol penetration values. Number-based monodisperse NaCl aerosol penetration measurements showed that the most penetrating particle size was in the 50 nm range for all respirator models tested, with the exception of one model at ~200 nm size. Respirator models containing electrostatic filter media also showed lower penetration values with the TSI 8130 photometric method than the number-based penetration obtained for the most penetrating monodisperse particles. Results suggest that to provide a more challenging respirator filter test method than what is currently used for respirators containing electrostatic media, the test method should utilize a sufficient number

  15. Characterization of small-to-medium head-and-face dimensions for developing respirator fit test panels and evaluating fit of filtering facepiece respirators with different faceseal design

    PubMed Central

    Lin, Yi-Chun

    2017-01-01

    A respirator fit test panel (RFTP) with facial size distribution representative of intended users is essential to the evaluation of respirator fit for new models of respirators. In this study an anthropometric survey was conducted among youths representing respirator users in mid-Taiwan to characterize head-and-face dimensions key to RFTPs for application to small-to-medium facial features. The participants were fit-tested for three N95 masks of different facepiece design and the results compared to facial size distribution specified in the RFTPs of bivariate and principal component analysis design developed in this study to realize the influence of facial characteristics to respirator fit in relation to facepiece design. Nineteen dimensions were measured for 206 participants. In fit testing the qualitative fit test (QLFT) procedures prescribed by the U.S. Occupational Safety and Health Administration were adopted. As the results show, the bizygomatic breadth of the male and female participants were 90.1 and 90.8% of their counterparts reported for the U.S. youths (P < 0.001), respectively. Compared to the bivariate distribution, the PCA design better accommodated variation in facial contours among different respirator user groups or populations, with the RFTPs reported in this study and from literature consistently covering over 92% of the participants. Overall, the facial fit of filtering facepieces increased with increasing facial dimensions. The total percentages of the tests wherein the final maneuver being completed was “Moving head up-and-down”, “Talking” or “Bending over” in bivariate and PCA RFTPs were 13.3–61.9% and 22.9–52.8%, respectively. The respirators with a three-panel flat fold structured in the facepiece provided greater fit, particularly when the users moved heads. When the facial size distribution in a bivariate RFTP did not sufficiently represent petite facial size, the fit testing was inclined to overestimate the general fit

  16. Characterization of small-to-medium head-and-face dimensions for developing respirator fit test panels and evaluating fit of filtering facepiece respirators with different faceseal design.

    PubMed

    Lin, Yi-Chun; Chen, Chen-Peng

    2017-01-01

    A respirator fit test panel (RFTP) with facial size distribution representative of intended users is essential to the evaluation of respirator fit for new models of respirators. In this study an anthropometric survey was conducted among youths representing respirator users in mid-Taiwan to characterize head-and-face dimensions key to RFTPs for application to small-to-medium facial features. The participants were fit-tested for three N95 masks of different facepiece design and the results compared to facial size distribution specified in the RFTPs of bivariate and principal component analysis design developed in this study to realize the influence of facial characteristics to respirator fit in relation to facepiece design. Nineteen dimensions were measured for 206 participants. In fit testing the qualitative fit test (QLFT) procedures prescribed by the U.S. Occupational Safety and Health Administration were adopted. As the results show, the bizygomatic breadth of the male and female participants were 90.1 and 90.8% of their counterparts reported for the U.S. youths (P < 0.001), respectively. Compared to the bivariate distribution, the PCA design better accommodated variation in facial contours among different respirator user groups or populations, with the RFTPs reported in this study and from literature consistently covering over 92% of the participants. Overall, the facial fit of filtering facepieces increased with increasing facial dimensions. The total percentages of the tests wherein the final maneuver being completed was "Moving head up-and-down", "Talking" or "Bending over" in bivariate and PCA RFTPs were 13.3-61.9% and 22.9-52.8%, respectively. The respirators with a three-panel flat fold structured in the facepiece provided greater fit, particularly when the users moved heads. When the facial size distribution in a bivariate RFTP did not sufficiently represent petite facial size, the fit testing was inclined to overestimate the general fit, thus for small

  17. Cleaning of Filtering Facepiece Respirators Contaminated with Mucin and Staphylococcus aureus

    DTIC Science & Technology

    2012-11-01

    Journal of Infection Control. Document contains color images. Decontamination and reuse of filtering facepiece respirators (FFRs) has been proposed to...in the area of cleaning FFRs. This study evaluates the cleaning of three surgical N95 FFRs by three commercial wipe products as an initial exploration...significantly higher penetration than the other wipe products. The significance of these data to the concept of decontamination and reuse of FFRs will remain

  18. Evaluation of the filtration performance of NIOSH-approved N95 filtering facepiece respirators by photometric and number-based test methods.

    PubMed

    Rengasamy, Samy; Miller, Adam; Eimer, Benjamin C

    2011-01-01

    N95 particulate filtering facepiece respirators are certified by measuring penetration levels photometrically with a presumed severe case test method using charge neutralized NaCl aerosols at 85 L/min. However, penetration values obtained by photometric methods have not been compared with count-based methods using contemporary respirators composed of electrostatic filter media and challenged with both generated and ambient aerosols. To better understand the effects of key test parameters (e.g., particle charge, detection method), initial penetration levels for five N95 model filtering facepiece respirators were measured using NaCl aerosols with the aerosol challenge and test equipment employed in the NIOSH respirator certification method (photometric) and compared with an ultrafine condensation particle counter method (count based) for the same NaCl aerosols as well as for ambient room air particles. Penetrations using the NIOSH test method were several-fold less than the penetrations obtained by the ultrafine condensation particle counter for NaCl aerosols as well as for room particles indicating that penetration measurement based on particle counting offers a more difficult challenge than the photometric method, which lacks sensitivity for particles < 100 nm. All five N95 models showed the most penetrating particle size around 50 nm for room air particles with or without charge neutralization, and at 200 nm for singly charged NaCl monodisperse particles. Room air with fewer charged particles and an overwhelming number of neutral particles contributed to the most penetrating particle size in the 50 nm range, indicating that the charge state for the majority of test particles determines the MPPS. Data suggest that the NIOSH respirator certification protocol employing the photometric method may not be a more challenging aerosol test method. Filter penetrations can vary among workplaces with different particle size distributions, which suggests the need for the

  19. [The aspiratory resistance and filtration penetration of N95 filtering-facepiece respirators used widely in China].

    PubMed

    Wang, Xinyan; Shi, Tingming; Lu, Wei; Qin, Shaoxian; Liu, Yuewei; Tao, Ying; Zhang, Hongge; Chen, Weihong

    2015-01-01

    The objective of this study was to investigate the aspiratory resistance, filtration penetration and their influence factors of N95 filtering-facepiece respirators used widely in China. The total of 6 brands and 21 models of N95 filtering-facepiece respirators which are certified and big sales on the market. The aspiratory resistance and filtration efficiency filter penetration were measured while air pump ran from 10 L/min to 100 L/min using differential pressure gauge and the PortaCount, respectively. The filtration penetrations for 2 of the 21 models were lower than 95%, and the qualified rate for all models was 90.47%. The filtration penetrations gradually decreased when ventilation flow of air pump increased. The negative correlation was observed between filtration penetration and ventilation flow (r(2) = 0.711, P < 0.05). The resistances of all 21 models of N95 respirators met the requirements of the national standard. The aspiratory resistance started to elevate with the increasing of ventilation flow, and a positive correlation between both (r(2) = 0.878, P < 0.05). Significant differences of filtration penetration and aspiratory resistance were observed among between different brands (P < 0.05) although no differences of filtration penetration existed among different models of one brand (P > 0.05). But the differences of the aspiratory resistance among different models of one brand were statistically significant (P < 0.05). The aspiratory resistances of all N95 filtering-facepiece respirators used in this study met the requirements of the national standard. And the qualified ratio of filtration penetration of all models was higher than 90%. The influencing factors of aspiratory resistance included materials, size and ventilation flow. And influencing factors for filtration penetration were materials and ventilation flow.

  20. N95 filtering facepiece respirator deadspace temperature and humidity.

    PubMed

    Roberge, Raymond J; Kim, Jung-Hyun; Benson, Stacey

    2012-01-01

    The objective of this study was to determine the levels of heat and humidity that develop within the deadspace of N95 filtering facepiece respirators (N95 FFR). Seventeen subjects wore two models each of N95 FFR and N95 FFR with an exhalation valve (N95 FFR/EV) while exercising on a treadmill at a low-moderate work rate for 1 and 2 hr in a temperate ambient environment. FFR deadspace temperature and relative humidity were monitored by a wireless sensor housed within the FFR. Each FFR was weighed pre- and post-testing to determine moisture retention. After 1 hr, FFR deadspace temperature and humidity were markedly elevated above ambient levels, and the FFR deadspace mean apparent heat index was 54°C. N95 FFR/EV use resulted in significantly lower deadspace temperatures than N95 FFR (p = 0.01), but FFR deadspace humidity levels were not significantly different (p = 0.32). Compared with the first hour of use, no significant increase in FFR deadspace heat and humidity occurred over the second hour. FFR mean moisture retention was < 0.3 grams over 2 hr. N95 FFR/EV offer a significant advantage in deadspace heat dissipation over N95 FFR at a low-moderate work rate over 1 hr of continuous use but offered no additional benefit in humidity amelioration. Moisture retention in N95 FFR and N95 FFR/EV is minimal after 2 hr of use. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a file containing N95 filtering facepiece respirator deadspace mean RH and temperature recordings for 17 subjects treadmill exercising at 5.6 Km/H over 1 hour.].

  1. Respiratory protection against Mycobacterium tuberculosis: quantitative fit test outcomes for five type N95 filtering-facepiece respirators.

    PubMed

    Lee, Kiyoung; Slavcev, Andrea; Nicas, Mark

    2004-01-01

    In preparing to fit test a large workforce, a respirator program manager needs to initially choose respirators that will fit the greatest proportion of employees and achieve the best fits. This article discusses our strategy in selecting respirators from an initial array of seven NIOSH-certified Type N95 filtering-facepiece devices for a respiratory protection program against Mycobacterium tuberculosis (M. tb) aerosol. The seven respirators were screened based on manufacturer-provided fit test data, comfort, and cost. From these 7 devices, 5 were chosen for quantitative fit testing on 40 subjects who were a convenience sample from a cohort of approximately 30,000 workers scheduled to undergo fit testing. Across the five brands, medium/regular-size respirators fit from 8% to 95% of the subjects; providing another size of the same brand improved the pass rates slightly. Gender was not found to significantly affect fit test pass rates for any respirator brand. Among test panel members, an Aearo Corporation respirator (TC 84A-2630) and a 3M Company respirator (TC 84A-0006) provided the highest overall pass rates of 98% and 90%, respectively. We selected these two brands for fit testing in the larger worker cohort. To date, these two respirators have provided overall pass rates of 98% (1793/1830) and 88% (50/57), respectively, which are similar to the test panel results. Among 1850 individuals who have been fit tested, 1843 (99.6%) have been successfully fitted with one or the other brand. In a separate analysis, we used the test panel pass rates to estimate the reduction in M. tb infection risk afforded by the medium/regular-size of five filtering-facepiece respirators. We posed a low-exposure versus a high-exposure scenario for health care workers and assumed that respirators could be assigned without conducting fit testing, as proposed by many hospital infection control practitioners. Among those who would pass versus fail the fit test, we assumed an average

  2. Gravimetric Measurements of Filtering Facepiece Respirators Challenged With Diesel Exhaust.

    PubMed

    Satish, Swathi; Swanson, Jacob J; Xiao, Kai; Viner, Andrew S; Kittelson, David B; Pui, David Y H

    2017-07-01

    Elevated concentrations of diesel exhaust have been linked to adverse health effects. Filtering facepiece respirators (FFRs) are widely used as a form of respiratory protection against diesel particulate matter (DPM) in occupational settings. Previous results (Penconek A, Drążyk P, Moskal A. (2013) Penetration of diesel exhaust particles through commercially available dust half masks. Ann Occup Hyg; 57: 360-73.) have suggested that common FFRs are less efficient than would be expected for this purpose based on their certification approvals. The objective of this study was to measure the penetration of DPM through NIOSH-certified R95 and P95 electret respirators to verify this result. Gravimetric-based penetration measurements conducted using polytetrafluoroethylene (PTFE) and polypropylene (PP) filters were compared with penetration measurements made with a Scanning Mobility Particle Sizer (SMPS, TSI Inc.), which measures the particle size distribution. Gravimetric measurements using PP filters were variable compared to SMPS measurements and biased high due to adsorption of gas phase organic material. Relatively inert PTFE filters adsorbed less gas phase organic material resulting in measurements that were more accurate. To attempt to correct for artifacts associated with adsorption of gas phase organic material, primary and secondary filters were used in series upstream and downstream of the FFR. Correcting for adsorption by subtracting the secondary mass from the primary mass improved the result for both PTFE and PP filters but this correction is subject to 'equilibrium' conditions that depend on sampling time and the concentration of particles and gas phase hydrocarbons. Overall, the results demonstrate that the use of filters to determine filtration efficiency of FFRs challenged with diesel exhaust produces erroneous results due to the presence of gas phase hydrocarbons in diesel exhaust and the tendency of filters to adsorb organic material. Published by

  3. Development of an Advanced Respirator Fit Test Headform (Postprint)

    DTIC Science & Technology

    2012-11-01

    needed to measure the fit of N95 filtering facepiece respirators (FFRs) for protection studies against viable airborne particles. The objective of...N95 filtering facepiece respirators (FFRs) for pro- tection studies against viable airborne particles. A Static (i.e., non-moving, non-speaking...The N95 class of filtering facepiece respirators (FFRs) is commonly used to re- duce exposure to airborne particles, including oil-free aerosols (dusts

  4. EFFECT OF WEARING AN N95 FILTERING FACEPIECE RESPIRATOR ON SUPEROMEDIAL ORBITAL INFRARED INDIRECT BRAIN TEMPERATURE MEASUREMENTS

    PubMed Central

    DiLeo, Travis; Roberge, Raymond J.; Kim, Jung-Hyun

    2016-01-01

    Purpose To determine any effect of wearing a filtering facepiece respirator on brain temperature. Methods Subjects (n=18) wore a filtering facepiece respirator (FFR) for 1h at rest while undergoing infrared thermography measurements of the superomedial periobital region of the eye, a non-invasive indirect method of brain temperature measurements we termed the superomedial orbital infrared indirect brain temperature (SOIIBT) measurement. Temperature of the facial skin covered by the FFR, infrared temperature measurements of the tympanic membrane and superficial temporal artery region were concurrently measured, and subjective impressions of thermal comfort obtained simultaneously. Results The temperature of the skin under the FFR and subjective impressions of thermal discomfort both increased significantly. The mean tympanic membrane temperature did not increase, and the superficial temporal artery region temperature decreased significantly. The SOIIBT values did not change significantly, but subjects who switched from nasal to oronasal breathing during the study (n=5) experienced a slight increase in the SOIIBT measurements. Conclusions Wearing a FFR for 1h at rest does not have a significant effect on brain temperatures, as evaluated by the SOIIBT measurements, but a change in the route of breathing may impact these measurements. These findings suggest that subjective impressions of thermal discomfort from wearing a FFR under the study conditions are more likely the result of local dermal sensations rather than brain warming. PMID:26759336

  5. 42 CFR 84.205 - Facepiece test; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... respirator will be fitted to the faces of persons having varying facial shapes and sizes. (b) Where the applicant specifies a facepiece size or sizes for the respirator together with the approximate measurement..., pumping with a tire pump into a 28-liter (1 cubic-foot) container. (4) Each wearer shall not detect the...

  6. The effect of simulated air conditions on N95 filtering facepiece respirators performance.

    PubMed

    Ramirez, Joel A; O'Shaughnessy, Patrick T

    2016-07-01

    The objective of this study was to determine the effect of several simulated air environmental conditions on the particle penetration and the breathing resistance of two N95 filtering facepiece respirator (FFR) models. The particle penetration and breathing resistance of the respirators were evaluated in a test system developed to mimic inhalation and exhalation breathing while relative humidity and temperature were modified. Breathing resistance was measured over 120 min using a calibrated pressure transducer under four different temperature and relative humidity conditions without aerosol loading. Particle penetration was evaluated before and after the breathing resistance test at room conditions using a sodium chloride aerosol measured with a scanning mobility particle sizer. Results demonstrated that increasing relative humidity and lowering external temperature caused significant increases in breathing resistance (p < 0.001). However, these same conditions did not influence the penetration or most penetrating particle size of the tested FFRs. The increase in breathing resistance varied by FFR model suggesting that some FFR media are less influenced by high relative humidity.

  7. Comparison of pressure drop and filtration efficiency of particulate respirators using welding fumes and sodium chloride.

    PubMed

    Cho, Hyun-Woo; Yoon, Chung-Sik; Lee, Jin-Ho; Lee, Seung-Joo; Viner, Andrew; Johnson, Erik W

    2011-07-01

    Respirators are used to help reduce exposure to a variety of contaminants in workplaces. Test aerosols used for certification of particulate respirators (PRs) include sodium chloride (NaCl), dioctyl phthalate, and paraffin oil. These aerosols are generally assumed to be worst case surrogates for aerosols found in the workplace. No data have been published to date on the performance of PRs with welding fumes, a hazardous aerosol that exists in real workplace settings. The aim of this study was to compare the performance of respirators and filters against a NaCl aerosol and a welding fume aerosol and determine whether or not a correlation between the two could be made. Fifteen commercial PRs and filters (seven filtering facepiece, two replaceable single-type filters, and six replaceable dual-type filters) were chosen for investigation. Four of the filtering facepiece respirators, one of the single-type filters, and all of the dual-type filters contained carbon to help reduce exposure to ozone and other vapors generated during the welding process. For the NaCl test, a modified National Institute for Occupational Safety and Health protocol was adopted for use with the TSI Model 8130 automated filter tester. For the welding fume test, welding fumes from mild steel flux-cored arcs were generated and measured with a SIBATA filter tester (AP-634A, Japan) and a manometer in the upstream and downstream sections of the test chamber. Size distributions of the two aerosols were measured using a scanning mobility particle sizer. Penetration and pressure drop were measured over a period of aerosol loading onto the respirator or filter. Photos and scanning electron microscope images of clean and exposed respirators were taken. The count median diameter (CMD) and mass median diameter (MMD) for the NaCl aerosol were smaller than the welding fumes (CMD: 74 versus 216 nm; MMD: 198 versus 528 nm, respectively). Initial penetration and peak penetration were higher with the NaCl aerosol

  8. Estimating the Dead Space Volume Between a Headform and N95 Filtering Facepiece Respirator Using Microsoft Kinect.

    PubMed

    Xu, Ming; Lei, Zhipeng; Yang, James

    2015-01-01

    N95 filtering facepiece respirator (FFR) dead space is an important factor for respirator design. The dead space refers to the cavity between the internal surface of the FFR and the wearer's facial surface. This article presents a novel method to estimate the dead space volume of FFRs and experimental validation. In this study, six FFRs and five headforms (small, medium, large, long/narrow, and short/wide) are used for various FFR and headform combinations. Microsoft Kinect Sensors (Microsoft Corporation, Redmond, WA) are used to scan the headforms without respirators and then scan the headforms with the FFRs donned. The FFR dead space is formed through geometric modeling software, and finally the volume is obtained through LS-DYNA (Livermore Software Technology Corporation, Livermore, CA). In the experimental validation, water is used to measure the dead space. The simulation and experimental dead space volumes are 107.5-167.5 mL and 98.4-165.7 mL, respectively. Linear regression analysis is conducted to correlate the results from Kinect and water, and R(2) = 0.85.

  9. Customized design and 3D printing of face seal for an N95 filtering facepiece respirator.

    PubMed

    Cai, Mang; Li, Hui; Shen, Shengnan; Wang, Yu; Yang, Quan

    2018-03-01

    Filtering Facepiece Respirator (FFR) is the most common respirator users in the health care environment utilize for personal protection from outside particles. Comfort and fit are important while wearing an FFR. This paper proposes a novel technology to produce customized face seal design for improving the wearing comfort and fit of FFR wearers. In order to customize the design of face seals, we scanned the faces of three subjects using three-dimensional (3D) laser scanning method. A customized face seal for a 3M 8210 N95 FFR for each headform was designed using reverse engineering technique. Next, the face seal prototypes were fabricated with Acrylonitrile Butadiene Styrene (ABS) plastic using the 3D printing method. A force sensing system based on Arduino Uno R3 was developed, and the force sensor of this system was inserted between the FFR and headform to measure contact pressure. Experimental results showed that the newly designed FFR face seal provided the subjects with an improved contact pressure.

  10. Resistance to synthetic blood penetration of National Institute for Occupational Safety and Health-approved N95 filtering facepiece respirators and surgical N95 respirators

    PubMed Central

    Rengasamy, Samy; Sbarra, Deborah; Nwoko, Julian; Shaffer, Ronald

    2015-01-01

    Background Surgical N95 filtering facepiece respirators (FFRs), certified by the National Institute for Occupational Safety and Health (NIOSH) as a respirator and cleared by the Food and Drug Administration (FDA) as a surgical mask, are often used to protect from the inhalation of infectious aerosols and from splashes/sprays of body fluids in health care facilities. A shortage of respirators can be expected during a pandemic. The availability of surgical N95 FFRs can potentially be increased by incorporating FDA clearance requirements in the NIOSH respirator approval process. Methods Fluid resistance of NIOSH-approved N95 FFRs, and FDA-cleared surgical N95 FFRs and surgical masks was tested using the ASTM F1862 method at 450 and 635 cm/sec velocities and compared with the results from a third-party independent laboratory. Blood penetration through different layers of filter media of masks were also analyzed visually. Results Four N95 FFR models showed no test failures at both velocities. The penetration results obtained in the NIOSH laboratory were comparable to those from the third-party independent laboratory. The number of respirator samples failing the test increased with increasing test velocity. Conclusions The results indicate that several NIOSH-approved N95 FFR models would likely pass FD clearance requirements for resistance to synthetic blood penetration. PMID:26231551

  11. [Respiratory protection provided by N95 filtering facepiece respirators and disposable medicine masks against airborne bacteria in different working environments].

    PubMed

    Lu, W; Zhu, X C; Zhang, X Y; Chen, Y T; Chen, W H

    2016-09-20

    Objective: To determine the relative protection provided by N95 filtering facepiece respirators (FFR) and disposable medicine masks (DMM) against airborne bacteria in different working environments. Methods: The field study was performed with 12 subjects wearing an N95 filtering facepiece respirator and a disposable medicine mask for 1h, respectively. Airborne microorganisms and bacteria samples from both the external (Ce) and the inner (Ci) surface of N95 FFR and DMM are collected. The Ce: Ci ratio was used to calculate the bacterial filtering proportion. Bacterial filtering efficiency (BFE) was measured using the JWL-2A Sampler. Results: The bacterial filtration efficiency of N95 FFR and DMM were 99.93% and 91.53%, respectively. There was significant difference between the two materials ( P <0.05). In summer, airborne bacterial concentration was higher than that in winter. In the same season, airborne bacterial concentration in hospital environment is higher than that in campus. The higher the airborne bacterial concentration, the greater bacterial contaminated on the external surface of the used masks. To all masks used in different working environment, bacterial contamination on the external surface was much greater than the inner surface ( P <0.01). Compared to N95 FFR, DMM had slighter bacterial contamination on the external surface and greater bacterial contamination on the inner surface. However, this difference was not significant ( P >0.05). The bacterial filtering proportion of N95 FFR is higher than DMM. These differences were significant in samples tested in summer ( P <0.05) , but were not significant in samples tested in winter ( P >0.05). Conclusion: Bacterial filtering efficiency of N95 respirator is superior to medicine mask, and this advantage become more obvious in high airborne bacterial concentration levels.

  12. 42 CFR 84.175 - Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Half-mask facepieces, full facepieces, hoods....175 Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements. (a) Half-mask facepieces and full facepieces shall be designed and constructed to fit persons with...

  13. A novel method for designing and fabricating low-cost facepiece prototypes.

    PubMed

    Joe, Paula S; Shum, Phillip C; Brown, David W; Lungu, Claudiu T

    2014-01-01

    In 2010, the National Institute for Occupational Safety and Health (NIOSH) published new digital head form models based on their recently updated fit-test panel. The new panel, based on the 2000 census to better represent the modern work force, created two additional sizes: Short/Wide and Long/Narrow. While collecting the anthropometric data that comprised the panel, additional three-dimensional data were collected on a subset of the subjects. Within each sizing category, five individuals' three-dimensional data were used to create the new head form models. While NIOSH has recommended a switch to a five-size system for designing respirators, little has been done in assessing the potential benefits of this change. With commercially available elastomeric facepieces available in only three or four size systems, it was necessary to develop the facepieces to enable testing. This study aims to develop a method for designing and fabricating elastomeric facepieces tailored to the new head form designs for use in fit-testing studies. This novel method used computed tomography of a solid silicone facepiece and a number of computer-aided design programs (VolView, ParaView, MEGG3D, and RapidForm XOR) to develop a facepiece model to accommodate the Short/Wide head form. The generated model was given a physical form by means of three-dimensional printing using stereolithography (SLA). The printed model was then used to create a silicone mold from which elastomeric prototypes can be cast. The prototype facepieces were cast in two types of silicone for use in future fit-testing.

  14. 42 CFR 84.118 - Half-mask facepieces, full facepieces, and mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.118 Half-mask facepieces, full facepieces, and... reduce the respiratory protective qualities of the gas mask. (c) Half-mask facepieces shall not interfere...

  15. 42 CFR 84.118 - Half-mask facepieces, full facepieces, and mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.118 Half-mask facepieces, full facepieces, and... reduce the respiratory protective qualities of the gas mask. (c) Half-mask facepieces shall not interfere...

  16. 42 CFR 84.118 - Half-mask facepieces, full facepieces, and mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.118 Half-mask facepieces, full facepieces, and... reduce the respiratory protective qualities of the gas mask. (c) Half-mask facepieces shall not interfere...

  17. 42 CFR 84.118 - Half-mask facepieces, full facepieces, and mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.118 Half-mask facepieces, full facepieces, and... reduce the respiratory protective qualities of the gas mask. (c) Half-mask facepieces shall not interfere...

  18. 42 CFR 84.118 - Half-mask facepieces, full facepieces, and mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.118 Half-mask facepieces, full facepieces, and... reduce the respiratory protective qualities of the gas mask. (c) Half-mask facepieces shall not interfere...

  19. Particulate Respirators Functionalized with Silver Nanoparticles Showed Excellent Real-Time Antimicrobial Effects against Pathogens.

    PubMed

    Zheng, Clark Renjun; Li, Shuai; Ye, Chengsong; Li, Xinyang; Zhang, Chiqian; Yu, Xin

    2016-07-05

    Particulate respirators designed to filtrate fine particulate matters usually do not possess antimicrobial functions. The current study aimed to functionalize particulate respirators with silver nanoparticles (nanosilver or AgNPs), which have excellent antimicrobial activities, utilizing a straightforward and effective method. We first enhanced the nanosilver-coating ability of nonwoven fabrics from a particulate respirator through surface modification by sodium oleate. The surfactant treatment significantly improved the fabrics' water wet preference where the static water contact angles reduced from 122° to 56°. Both macroscopic agar-plate tests and microscopic scanning electron microscope (SEM) characterization revealed that nanosilver functionalized fabrics could effectively inhibit the growth of two model bacterial strains (i.e., Staphylococcus aureus and Pseudomonas aeruginosa). The coating of silver nanoparticles would not affect the main function of particulate respirators (i.e., filtration of fine air-borne particles). Nanosilver coated particulate respirators with excellent antimicrobial activities can provide real-time protection to people in regions with severe air pollution against air-borne pathogens.

  20. 42 CFR 84.206 - Particulate tests; respirators with filters; minimum requirements; general.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Particulate tests; respirators with filters... filters; minimum requirements; general. (a) Three respirators with cartridges containing, or having attached to them, filters for protection against particulates will be tested in accordance with the...

  1. 42 CFR 84.206 - Particulate tests; respirators with filters; minimum requirements; general.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Particulate tests; respirators with filters... filters; minimum requirements; general. (a) Three respirators with cartridges containing, or having attached to them, filters for protection against particulates will be tested in accordance with the...

  2. 42 CFR 84.206 - Particulate tests; respirators with filters; minimum requirements; general.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Particulate tests; respirators with filters... filters; minimum requirements; general. (a) Three respirators with cartridges containing, or having attached to them, filters for protection against particulates will be tested in accordance with the...

  3. 42 CFR 84.206 - Particulate tests; respirators with filters; minimum requirements; general.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Particulate tests; respirators with filters... filters; minimum requirements; general. (a) Three respirators with cartridges containing, or having attached to them, filters for protection against particulates will be tested in accordance with the...

  4. 42 CFR 84.206 - Particulate tests; respirators with filters; minimum requirements; general.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Particulate tests; respirators with filters... filters; minimum requirements; general. (a) Three respirators with cartridges containing, or having attached to them, filters for protection against particulates will be tested in accordance with the...

  5. Cardiovascular Benefits of Wearing Particulate-Filtering Respirators: A Randomized Crossover Trial

    PubMed Central

    Shi, Jingjin; Lin, Zhijing; Chen, Renjie; Wang, Cuicui; Yang, Changyuan; Cai, Jing; Lin, Jingyu; Xu, Xiaohui; Ross, Jennifer A.; Zhao, Zhuohui; Kan, Haidong

    2016-01-01

    Background: Practical approaches to protect individuals from ambient particulate matter (PM) are urgently needed in developing countries. Evidence on the health benefits of wearing particulate-filtering respirators is limited. Objectives: We evaluated the short-term cardiovascular health effects of wearing respirators in China. Methods: A randomized crossover trial was performed in 24 healthy young adults in Shanghai, China in 2014. The subjects were randomized into two groups and wore particulate-filtering respirators for 48 hr alternating with a 3-week washout interval. Heart rate variability (HRV) and ambulatory blood pressure (BP) were continuously monitored during the 2nd 24 hr in each intervention. Circulating biomarkers were measured at the end of each intervention. Linear mixed-effect models were applied to evaluate the effects of wearing respirators on health outcomes. Results: During the intervention periods, the mean daily average concentration of PM with an aerodynamic diameter < 2.5 μm (PM2.5) was 74.2 μg/m3. Compared with the absence of respirators, wearing respirators was associated with a decrease of 2.7 mmHg [95% confidence interval (CI): 0.1, 5.2 mmHg] in systolic BP and increases of HRV parameters, including 12.5% (95% CI: 3.8%, 21.2%) in high frequency (HF) power, 10.9% (95% CI: 1.8%, 20.0%) in the root mean square of the successive differences, and 22.1% (95% CI: 3.6%, 40.7%) in the percentage of normal RR intervals with duration > 50 msec different from the previous normal RR interval (pNN50). The presence of respirators was also associated with a decrease of 7.8% (95% CI: 3.5%, 12.1%) in the ratio of low frequency (LF)/HF power. Conclusions: Short-term wearing of particulate-filtering respirators may produce cardiovascular benefits by improving autonomic nervous function and reducing BP. Citation: Shi J, Lin Z, Chen R, Wang C, Yang C, Cai J, Lin J, Xu X, Ross JA, Zhao Z, Kan H. 2017. Cardiovascular benefits of wearing particulate

  6. 42 CFR 84.131 - Supplied-air respirators; required components.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Facepiece, hood, or helmet; (2) Air supply valve, orifice, or demand or pressure-demand regulator; (3) Hand... 42 Public Health 1 2010-10-01 2010-10-01 false Supplied-air respirators; required components. 84... Supplied-Air Respirators § 84.131 Supplied-air respirators; required components. (a) Each supplied-air...

  7. Effect of fit testing on the protection offered by n95 filtering facepiece respirators against fine particles in a laboratory setting.

    PubMed

    Reponen, Tiina; Lee, Shu-An; Grinshpun, Sergey A; Johnson, Erik; McKay, Roy

    2011-04-01

    This study investigated particle-size-selective protection factors (PFs) of four models of N95 filtering facepiece respirators (FFRs) that passed and failed fit testing. Particle size ranges were representative of individual viruses and bacteria (aerodynamic diameter d(a) = 0.04-1.3 μm). Standard respirator fit testing was followed by particle-size-selective measurement of PFs while subjects wore N95 FFRs in a test chamber. PF values obtained for all subjects were then compared to those obtained for the subjects who passed the fit testing. Overall fit test passing rate for all four models of FFRs was 67%. Of these, 29% had PFs <10 (the Occupational Safety and Health Administration Assigned Protection Factor designated for this type of respirator). When only subjects that passed fit testing were included, PFs improved with 9% having values <10. On average, the PFs were 1.4 times (29.5/21.5) higher when only data for those who passed fit testing were included. The minimum PFs were consistently observed in the particle size range of 0.08-0.2 μm. Overall PFs increased when subjects passed fit testing. The results support the value of fit testing but also show for the first time that PFs are dependent on particle size regardless of fit testing status.

  8. Development of a new test system to determine penetration of multi-walled carbon nanotubes through filtering facepiece respirators

    PubMed Central

    Vo, Evanly; Zhuang, Ziqing

    2015-01-01

    Carbon nanotubes (CNTs) are currently used in numerous industrial and biomedical applications. Recent studies suggest that workers may be at risk of adverse health effects if they are exposed to CNTs. A National Institute for Occupational Safety and Health (NIOSH) survey of the carbonaceous nanomaterial industry found that 77% of the companies used respiratory protection. Elastomeric half-mask respirators and filtering facepiece respirators (FFRs) are commonly used. Although numerous respirator filtration studies have been done with surrogate engineered nanoparticles, such as sodium chloride, penetration data from engineered nanoparticles such as CNTs are lacking. The aims of this study were to develop a new CNT aerosol respirator testing system and to determine multi-walled CNT (MWCNT) penetration through FFRs. A custom-designed CNT aerosol respirator testing system (CNT-ARTS) was developed which was capable of producing a sufficient amount of airborne MWCNTs for testing of high efficiency FFRs. The size distribution of airborne MWCNTs was 20–10,000 nm, with 99% of the particles between 25 and 2840 nm. The count median diameter (CMD) was 209 nm with a geometric standard deviation (GSD) of 1.98. This particle size range is similar to those found in some work environments (particles ≤6000 nm). The penetration of MWCNTs through six tested FFR models at two constant flow rates of 30 and 85 LPM was determined. Penetration at 85 LPM (0.58–2.04% for N95, 0.15–0.32% for N99, and 0.007–0.009% for P100 FFRs) was greater compared with the values at 30 LPM (0.28–1.79% for N95, 0.10–0.24% for N99, and 0.005–0.006% for P100 FFRs). The most penetrating particle size through all six tested FFR models was found to be in the range of 25–130 nm and 35–200 nm for the 30-LPM and 85-LPM flow rates, respectively. PMID:26166842

  9. Capture of 0.1-μm aerosol particles containing viable H1N1 influenza virus by N95 filtering facepiece respirators.

    PubMed

    Harnish, Delbert A; Heimbuch, Brian K; Balzli, Charles; Choe, Melanie; Lumley, April E; Shaffer, Ronald E; Wander, Joseph D

    2016-01-01

    Nosocomial infections pose an escalating threat to both patients and healthcare workers (HCWs). A widely recommended device for individual respiratory protection, the N95 filtering facepiece respirator (FFR) has been shown to provide efficient filtration of inert particles larger and smaller than the nominal most-penetrating particle size (MPPS) range, 0.03-0.3 μm. Humans generate respiratory aerosols in the MPPS range, suggesting that short-range disease transmission could occur via small infectious particles. Data presented here show that the N95 FFR will afford a significant measure of protection against infectious particles as small as a bare H1N1 influenza virion, and that the capture mechanism does not discriminate in favor of, or against, biological particles.

  10. Evaluation of Microwave Steam Bags for the Decontamination of Filtering Facepiece Respirators

    PubMed Central

    Fisher, Edward M.; Williams, Jessica L.; Shaffer, Ronald E.

    2011-01-01

    Reusing filtering facepiece respirators (FFRs) has been suggested as a strategy to conserve available supplies for home and healthcare environments during an influenza pandemic. For reuse to be possible, used FFRs must be decontaminated before redonning to reduce the risk of virus transmission; however, there are no approved methods for FFR decontamination. An effective method must reduce the microbial threat, maintain the function of the FFR, and present no residual chemical hazard. The method should be readily available, inexpensive and easily implemented by healthcare workers and the general public. Many of the general decontamination protocols used in healthcare and home settings are unable to address all of the desired qualities of an efficient FFR decontamination protocol. The goal of this study is to evaluate the use of two commercially available steam bags, marketed to the public for disinfecting infant feeding equipment, for FFR decontamination. The FFRs were decontaminated with microwave generated steam following the manufacturers' instructions then evaluated for water absorption and filtration efficiency for up to three steam exposures. Water absorption of the FFR was found to be model specific as FFRs constructed with hydrophilic materials absorbed more water. The steam had little effect on FFR performance as filtration efficiency of the treated FFRs remained above 95%. The decontamination efficacy of the steam bag was assessed using bacteriophage MS2 as a surrogate for a pathogenic virus. The tested steam bags were found to be 99.9% effective for inactivating MS2 on FFRs; however, more research is required to determine the effectiveness against respiratory pathogens. PMID:21525995

  11. Facepiece Material Survey

    DTIC Science & Technology

    1990-07-01

    be the best selection to meet the facepiece criteria. Accession For NTIS GRA&I DTIC TAB I] Unannounced 13 Just ifcatio By Distribution/ Availability...considered the most important factor in material selection . HD and GD resistance were recently reported for a broad range of elastomers. 1 While these...not be an issue. The concept of multiple strippable layers does not appear feasible for the facepiece. This concept calls for incorporating

  12. 40 CFR 721.10077 - 3H-1,2,4-Triazol-3-one, 1,2-dihydro-.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-fitting respirator equipped with N100 (if aerosols absent), R100, or P100 filters (either half- or full... Efficiency Particulate Air (HEPA) filters; powered air-purifying respirator equipped with a tight-fitting facepiece (either half- or full-face) and HEPA filters; and supplied-air respirator operated in pressure...

  13. 40 CFR 721.10077 - 3H-1,2,4-Triazol-3-one, 1,2-dihydro-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-fitting respirator equipped with N100 (if aerosols absent), R100, or P100 filters (either half- or full... Efficiency Particulate Air (HEPA) filters; powered air-purifying respirator equipped with a tight-fitting facepiece (either half- or full-face) and HEPA filters; and supplied-air respirator operated in pressure...

  14. 40 CFR 721.10077 - 3H-1,2,4-Triazol-3-one, 1,2-dihydro-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-fitting respirator equipped with N100 (if aerosols absent), R100, or P100 filters (either half- or full... Efficiency Particulate Air (HEPA) filters; powered air-purifying respirator equipped with a tight-fitting facepiece (either half- or full-face) and HEPA filters; and supplied-air respirator operated in pressure...

  15. 40 CFR 721.10077 - 3H-1,2,4-Triazol-3-one, 1,2-dihydro-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-fitting respirator equipped with N100 (if aerosols absent), R100, or P100 filters (either half- or full... Efficiency Particulate Air (HEPA) filters; powered air-purifying respirator equipped with a tight-fitting facepiece (either half- or full-face) and HEPA filters; and supplied-air respirator operated in pressure...

  16. Fit Assessment of N95 Filtering-Facepiece Respirators in the U.S. Centers for Disease Control and Prevention Strategic National Stockpile.

    PubMed

    Bergman, Michael; Zhuang, Ziqing; Brochu, Elizabeth; Palmiero, Andrew

    National Institute for Occupational Safety and Health (NIOSH)-approved N95 filtering-facepiece respirators (FFR) are currently stockpiled by the U.S. Centers for Disease Control and Prevention (CDC) for emergency deployment to healthcare facilities in the event of a widespread emergency such as an influenza pandemic. This study assessed the fit of N95 FFRs purchased for the CDC Strategic National Stockpile. The study addresses the question of whether the fit achieved by specific respirator sizes relates to facial size categories as defined by two NIOSH fit test panels. Fit test data were analyzed from 229 test subjects who performed a nine-donning fit test on seven N95 FFR models using a quantitative fit test protocol. An initial respirator model selection process was used to determine if the subject could achieve an adequate fit on a particular model; subjects then tested the adequately fitting model for the nine-donning fit test. Only data for models which provided an adequate initial fit (through the model selection process) for a subject were analyzed for this study. For the nine-donning fit test, six of the seven respirator models accommodated the fit of subjects (as indicated by geometric mean fit factor > 100) for not only the intended NIOSH bivariate and PCA panel sizes corresponding to the respirator size, but also for other panel sizes which were tested for each model. The model which showed poor performance may not be accurately represented because only two subjects passed the initial selection criteria to use this model. Findings are supportive of the current selection of facial dimensions for the new NIOSH panels. The various FFR models selected for the CDC Strategic National Stockpile provide a range of sizing options to fit a variety of facial sizes.

  17. Fit Assessment of N95 Filtering-Facepiece Respirators in the U.S. Centers for Disease Control and Prevention Strategic National Stockpile

    PubMed Central

    Bergman, Michael; Zhuang, Ziqing; Brochu, Elizabeth; Palmiero, Andrew

    2016-01-01

    National Institute for Occupational Safety and Health (NIOSH)-approved N95 filtering-facepiece respirators (FFR) are currently stockpiled by the U.S. Centers for Disease Control and Prevention (CDC) for emergency deployment to healthcare facilities in the event of a widespread emergency such as an influenza pandemic. This study assessed the fit of N95 FFRs purchased for the CDC Strategic National Stockpile. The study addresses the question of whether the fit achieved by specific respirator sizes relates to facial size categories as defined by two NIOSH fit test panels. Fit test data were analyzed from 229 test subjects who performed a nine-donning fit test on seven N95 FFR models using a quantitative fit test protocol. An initial respirator model selection process was used to determine if the subject could achieve an adequate fit on a particular model; subjects then tested the adequately fitting model for the nine-donning fit test. Only data for models which provided an adequate initial fit (through the model selection process) for a subject were analyzed for this study. For the nine-donning fit test, six of the seven respirator models accommodated the fit of subjects (as indicated by geometric mean fit factor > 100) for not only the intended NIOSH bivariate and PCA panel sizes corresponding to the respirator size, but also for other panel sizes which were tested for each model. The model which showed poor performance may not be accurately represented because only two subjects passed the initial selection criteria to use this model. Findings are supportive of the current selection of facial dimensions for the new NIOSH panels. The various FFR models selected for the CDC Strategic National Stockpile provide a range of sizing options to fit a variety of facial sizes. PMID:26877587

  18. Application of direct-reading and elemental carbon analysis methods to measure mass-based penetration of carbon nanotubes through elastomeric half-face and filtering facepiece respirators.

    PubMed

    Vo, Evanly; Zhuang, Ziqing; Birch, Eileen; Birch, Quinn

    2016-01-01

    The aim of this study was to apply a direct-reading aerosol instrument method and an elemental carbon (EC) analysis method to measure the mass-based penetration of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) through elastomeric half-mask respirators (EHRs) and filtering facepiece respirators (FFRs). For the direct-reading aerosol instrument method, two scanning mobility particle sizer/aerodynamic particle sizer systems were used to simultaneously determine the upstream (outside respirator) and downstream (inside respirator) test aerosols. For the EC analysis method, upstream and downstream CNTs were collected on filter cassettes and then analyzed using a thermal-optical technique. CNT mass penetrations were found in both methods to be within the associated efficiency requirements for each type and class of the respirator models that were tested. Generally, the penetrations of SWCNTs and MWCNTs had a similar trend with penetration being the highest for the N95 EHRs, followed by N95 FFRs, P100 EHRs, and P100 FFRs. This trend held true for both methods; however, the CNT penetration determined by the direct-reading aerosol instrument method (0.009-1.09% for SWCNTs and 0.005-0.21% for MWCNTs) was greater relative to the penetration values found through EC analysis method (0.007-0.69% for SWCNTs and 0.004-0.13% for MWCNTs). The results of this study illustrate considerations for how the methods can be used to evaluate penetration of morphologically complex materials through FFRs and EHRs.

  19. 42 CFR 84.179 - Non-powered air-purifying particulate respirators; filter identification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...; filter identification. 84.179 Section 84.179 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH...-purifying particulate respirators; filter identification. (a) The respirator manufacturer, as part of the application for certification, shall specify the filter series and the filter efficiency level (i.e., “N95...

  20. 42 CFR 84.179 - Non-powered air-purifying particulate respirators; filter identification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...; filter identification. 84.179 Section 84.179 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH...-purifying particulate respirators; filter identification. (a) The respirator manufacturer, as part of the application for certification, shall specify the filter series and the filter efficiency level (i.e., “N95...

  1. 42 CFR 84.179 - Non-powered air-purifying particulate respirators; filter identification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...; filter identification. 84.179 Section 84.179 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH...-purifying particulate respirators; filter identification. (a) The respirator manufacturer, as part of the application for certification, shall specify the filter series and the filter efficiency level (i.e., “N95...

  2. 42 CFR 84.179 - Non-powered air-purifying particulate respirators; filter identification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...; filter identification. 84.179 Section 84.179 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH...-purifying particulate respirators; filter identification. (a) The respirator manufacturer, as part of the application for certification, shall specify the filter series and the filter efficiency level (i.e., “N95...

  3. 42 CFR 84.179 - Non-powered air-purifying particulate respirators; filter identification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...; filter identification. 84.179 Section 84.179 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH...-purifying particulate respirators; filter identification. (a) The respirator manufacturer, as part of the application for certification, shall specify the filter series and the filter efficiency level (i.e., “N95...

  4. 46 CFR Appendix E to Subpart C to... - Respirator Fit Tests

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... provides the most comfortable fit. Each respirator represents a different size and shape and, if fitted and... only a preliminary review and must not constitute the subject's formal training on respirator use. (c... projects under the facepiece or otherwise interferes with a satisfactory fit must be altered or removed. (j...

  5. 46 CFR Appendix E to Subpart C to... - Respirator Fit Tests

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... provides the most comfortable fit. Each respirator represents a different size and shape and, if fitted and... only a preliminary review and must not constitute the subject's formal training on respirator use. (c... projects under the facepiece or otherwise interferes with a satisfactory fit must be altered or removed. (j...

  6. 42 CFR 84.1135 - Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements. 84.1135 Section 84.1135 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED...

  7. 42 CFR 84.1135 - Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements. 84.1135 Section 84.1135 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED...

  8. 42 CFR 84.1135 - Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements. 84.1135 Section 84.1135 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED...

  9. 42 CFR 84.1135 - Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements. 84.1135 Section 84.1135 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED...

  10. 42 CFR 84.1135 - Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements. 84.1135 Section 84.1135 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED...

  11. Respirator use and its impact on particulate matter exposure in aluminum manufacturing facilities.

    PubMed

    Liu, Sa; Noth, Elizabeth; Eisen, Ellen; Cullen, Mark R; Hammond, Katharine

    2018-05-31

    Objectives As part of a large epidemiologic study of particulate health effect, this study aimed to report respirator use among total particulate matter (TPM) samples collected in a major aluminum manufacturing company from 1966‒2013 and evaluate the impact of respirator-use adjustment on exposure estimation. Methods Descriptive analyses were performed to evaluate respirator use across facilities and by facility type and job. Protection factors were applied to TPM measurements for recorded respirator use. Estimated TPM exposure for each job ‒ before and after respirator-use adjustment ‒ were compared to assess the impact of adjustment on exposure estimation. Results Respirator use was noted for 37% of 12 402 full-shift personal TPM samples. Measured TPM concentration ranged from less than detectable to 8220 mg/m3, with arithmetic mean, median and standard deviation being 10.6, 0.87 and 130 mg/m 3 , respectively. Respirators were used more often in smelting facilities (52% of TPM measurements) than in fabricating (17%) or refinery facilities (28%) (P<0.01). Sixty-two percent of jobs in smelting facilities were subject to respirator-use adjustment, whereas it was 20% and 70% in fabricating and refinery facilities, respectively. Applying protection factors to TPM measurements significantly reduced estimated job mean TPM exposures and changed exposure categories in these facilities, with larger impact in smelting than fabricating facilities. Conclusions Respirator use varied by time, facility and job. Adjusting respirator use resulted in differential impact in smelting and fabricating facilities, which will need to be incorporated into ongoing epidemiologic studies accordingly.

  12. Anti-Fog Solution for Air-Purifying Respirator Lenses

    DTIC Science & Technology

    2010-06-01

    INTRODUCTION Fogging of respirator and protective eyewear lenses occurs when water vapor condenses on the surface of the lens. Topical coatings, such as... safety goggles and six full-facepiece APRs to create 12 Snellen visual acuity conditions. The foils were calibrated during prior unpublished human

  13. Performance of Facepiece Respirators and Surgical Masks Against Surgical Smoke: Simulated Workplace Protection Factor Study.

    PubMed

    Gao, Shuang; Koehler, Richard H; Yermakov, Michael; Grinshpun, Sergey A

    2016-06-01

    Surgical smoke generated during electrocautery contains toxins which may cause adverse health effects to operating room (OR) personnel. The objective of this study was to investigate the performance of surgical masks (SMs), which are routinely used in ORs, more efficient N95 surgical mask respirator (SMRs) and N100 filtering facepiece respirator (FFRs), against surgical smoke. Ten subjects were recruited to perform surgical dissections on animal tissue in a simulated OR chamber, using a standard electrocautery device, generating surgical smoke. Six respiratory protective devices (RPDs) were tested: two SMs, two SMRs, and two N100 FFRs [including a newly developed faceseal (FS) prototype]. Fit testing was conducted before the experiment. Each subject was then exposed to the surgical smoke while wearing an RPD under the tests. Concentrations inside (C in) and outside (C out) of the RPD were measured by a particle size spectrometer. The simulated workplace protection factor (SWPF) was determined by the ratio of C out and C in for each RPD-wearing subject. For the SMs, the geometric means of SWPFtotal (based on the total aerosol concentration) were 1.49 and 1.76, indicating minimal protection. The SWPFtotal values of the SMRs and N100 FFRs were significantly higher than those of the SMs: for the two SMRs, the SWPFtotal were 208 and 263; for the two N100s, the SWPFtotal values were 1,089 and 2,199. No significant difference was observed between either the two SMs or the two SMRs. The SWPFtotal for the novel FS prototype N100 FFR was significantly higher than the conventional N100 FFR. The correlation between SWPFtotal and fit factor (FF) determined for two N95 SMRs was not significant. SMs do not provide measurable protection against surgical smoke. SMRs offer considerably improved protection versus SMs, while the N100 FFRs showed significant improvement over the SMRs. The FS prototype offered a higher level of protection than the standard N100 FFR, due to a tighter

  14. Penetration of Combustion Aerosol Particles Through Filters of NIOSH-Certified Filtering Facepiece Respirators (FFRs).

    PubMed

    Gao, Shuang; Kim, Jinyong; Yermakov, Michael; Elmashae, Yousef; He, Xinjian; Reponen, Tiina; Grinshpun, Sergey A

    2015-01-01

    Filtering facepiece respirators (FFRs) are commonly worn by first responders, first receivers, and other exposed groups to protect against exposure to airborne particles, including those originated by combustion. Most of these FFRs are NIOSH-certified (e.g., N95-type) based on the performance testing of their filters against charge-equilibrated aerosol challenges, e.g., NaCl. However, it has not been examined if the filtration data obtained with the NaCl-challenged FFR filters adequately represent the protection against real aerosol hazards such as combustion particles. A filter sample of N95 FFR mounted on a specially designed holder was challenged with NaCl particles and three combustion aerosols generated in a test chamber by burning wood, paper, and plastic. The concentrations upstream (Cup) and downstream (Cdown) of the filter were measured with a TSI P-Trak condensation particle counter and a Grimm Nanocheck particle spectrometer. Penetration was determined as (Cdown/Cup) ×100%. Four test conditions were chosen to represent inhalation flows of 15, 30, 55, and 85 L/min. Results showed that the penetration values of combustion particles were significantly higher than those of the "model" NaCl particles (p < 0.05), raising a concern about applicability of the N95 filters performance obtained with the NaCl aerosol challenge to protection against combustion particles. Aerosol type, inhalation flow rate and particle size were significant (p < 0.05) factors affecting the performance of the N95 FFR filter. In contrast to N95 filters, the penetration of combustion particles through R95 and P95 FFR filters (were tested in addition to N95) were not significantly higher than that obtained with NaCl particles. The findings were attributed to several effects, including the degradation of an N95 filter due to hydrophobic organic components generated into the air by combustion. Their interaction with fibers is anticipated to be similar to those involving "oily" particles

  15. 42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... respirator, pressure-demand class; minimum requirements. 84.157 Section 84.157 Public Health PUBLIC HEALTH... test; Type C supplied-air respirator, pressure-demand class; minimum requirements. (a) The static... the facepiece shall not fall below atmospheric at inhalation airflows less than 115 liters (4 cubic...

  16. 42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... respirator, pressure-demand class; minimum requirements. 84.157 Section 84.157 Public Health PUBLIC HEALTH... test; Type C supplied-air respirator, pressure-demand class; minimum requirements. (a) The static... the facepiece shall not fall below atmospheric at inhalation airflows less than 115 liters (4 cubic...

  17. Modeling the filtration ability of stockpiled filtering facepiece

    NASA Astrophysics Data System (ADS)

    Rottach, Dana R.

    2016-03-01

    Filtering facepiece respirators (FFR) are often stockpiled for use during public health emergencies such as an infectious disease outbreak or pandemic. While many stockpile administrators are aware of shelf life limitations, environmental conditions can lead to premature degradation. Filtration performance of a set of FFR retrieved from a storage room with failed environmental controls was measured. Though within the expected shelf life, the filtration ability of several respirators was degraded, allowing twice the penetration of fresh samples. The traditional picture of small particle capture by fibrous filter media qualitatively separates the effect of inertial impaction, interception from the streamline, diffusion, settling, and electrostatic attraction. Most of these mechanisms depend upon stable conformational properties. However, common FFR rely on electrets to achieve their high performance, and over time heat and humidity can cause the electrostatic media to degrade. An extension of the Langevin model with correlations to classical filtration concepts will be presented. The new computational model will be used to predict the change in filter effectiveness as the filter media changes with time.

  18. Effects of respirators under heat/work conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    James, R.; Dukes-Dobos, F.; Smith, R.

    Physiological responses and perceived strain of five unacclimatized male subjects were studied. The subjects were exposed to heat during an exercise task and were evaluated while wearing half and full facepiece, cartridge-type, air-purifying respirators, and without a respirator. The exercise consisted of walking on a treadmill for a period of 1 hour in a controlled environmental chamber at each of two different energy expenditure levels (200 and 400 kcal/hr)(approx. = 58 and 116 Watts) and two different heat exposures (air temperatures of 25/sup 0/C and 43.3./sup 0/C). The results indicated that wearing a full facepiece respirator imposed significant physiological strainmore » added to that caused by the heat and workloads used in the study. Five of the six physiological measures show this increased physiological strain: (1) heart rate; (2) minute ventilation; (3) oxygen consumption; (4) energy expenditure; and (5) oral temperature. There was no detectable effect on sweat rate. Although subjective ratings indicated more discomfort with increasing physiological strain, the observed correlations between such measures were low (T/sub b/ < .60). The net consequence of the significant effects indicates that workers' tolerance to moderate or high levels of work under hot conditions while wearing a respirator is reduced. The reduction is more pronounced when wearing a full mask than when wearing a half mask. Changes in respirator design which minimize respiratory dead space are suggested to alleviate this problem. Otherwise, prevention of excessive physiological strain from respirator use when working at moderate or higher levels at hot job sites could necessitate more rest breaks or limiting work time under such conditions.« less

  19. 42 CFR 84.75 - Half-mask facepieces, full facepieces, mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.75 Half-mask facepieces, full... which shall not reduce the respiratory protective qualities of the apparatus. (c) Apparatus with...

  20. 42 CFR 84.75 - Half-mask facepieces, full facepieces, mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.75 Half-mask facepieces, full... which shall not reduce the respiratory protective qualities of the apparatus. (c) Apparatus with...

  1. 42 CFR 84.75 - Half-mask facepieces, full facepieces, mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.75 Half-mask facepieces, full... which shall not reduce the respiratory protective qualities of the apparatus. (c) Apparatus with...

  2. 42 CFR 84.75 - Half-mask facepieces, full facepieces, mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.75 Half-mask facepieces, full... which shall not reduce the respiratory protective qualities of the apparatus. (c) Apparatus with...

  3. 42 CFR 84.75 - Half-mask facepieces, full facepieces, mouthpieces; fit; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.75 Half-mask facepieces, full... which shall not reduce the respiratory protective qualities of the apparatus. (c) Apparatus with...

  4. Challenge of N95 Filtering Facepiece Respirators with Viable H1N1 Influenza Aerosols

    PubMed Central

    Harnish, Delbert A.; Heimbuch, Brian K.; Husband, Michael; Lumley, April E.; Kinney, Kimberly; Shaffer, Ronald E.; Wander, Joseph D.

    2015-01-01

    OBJECTIVE Specification of appropriate personal protective equipment for respiratory protection against influenza is somewhat controversial. In a clinical environment, N95 filtering facepiece respirators (FFRs) are often recommended for respiratory protection against infectious aerosols. This study evaluates the ability of N95 FFRs to capture viable H1N1 influenza aerosols. METHODS Five N95 FFR models were challenged with aerosolized viable H1N1 influenza and inert polystyrene latex particles at continuous flow rates of 85 and 170 liters per minute. Virus was assayed using Madin-Darby canine kidney cells to determine the median tissue culture infective dose (TCID50). Aerosols were generated using a Collison nebulizer containing H1N1 influenza virus at 1 × 108 TCID50/mL. To determine filtration efficiency, viable sampling was performed upstream and downstream of the FFR. RESULTS N95 FFRs filtered 0.8-µm particles of both H1N1 influenza and inert origins with more than 95% efficiency. With the exception of 1 model, no statistically significant difference in filtration performance was observed between influenza and inert particles of similar size. Although statistically significant differences were observed for 2 models when comparing the 2 flow rates, the differences have no significance to protection. CONCLUSIONS This study empirically demonstrates that a National Institute for Occupational Safety and Health–approved N95 FFR captures viable H1N1 influenza aerosols as well as or better than its N95 rating, suggesting that a properly fitted FFR reduces inhalation exposure to airborne influenza virus. This study also provides evidence that filtration efficiency is based primarily on particle size rather than the nature of the particle’s origin. PMID:23571366

  5. 42 CFR 84.1157 - Chemical cartridge respirators with particulate filters; performance requirements; general.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Chemical cartridge respirators with particulate filters; performance requirements; general. 84.1157 Section 84.1157 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES...

  6. 42 CFR 84.1157 - Chemical cartridge respirators with particulate filters; performance requirements; general.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Chemical cartridge respirators with particulate filters; performance requirements; general. 84.1157 Section 84.1157 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES...

  7. 42 CFR 84.1157 - Chemical cartridge respirators with particulate filters; performance requirements; general.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Chemical cartridge respirators with particulate filters; performance requirements; general. 84.1157 Section 84.1157 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES...

  8. 42 CFR 84.1157 - Chemical cartridge respirators with particulate filters; performance requirements; general.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Chemical cartridge respirators with particulate filters; performance requirements; general. 84.1157 Section 84.1157 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES...

  9. 42 CFR 84.1157 - Chemical cartridge respirators with particulate filters; performance requirements; general.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Chemical cartridge respirators with particulate filters; performance requirements; general. 84.1157 Section 84.1157 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES...

  10. Efficiency of Respirator Filter Media against Diesel Particulate Matter: A Comparison Study Using Two Diesel Particulate Sources.

    PubMed

    Burton, Kerrie A; Whitelaw, Jane L; Jones, Alison L; Davies, Brian

    2016-07-01

    Diesel engines have been a mainstay within many industries since the early 1900s. Exposure to diesel particulate matter (DPM) is a major issue in many industrial workplaces given the potential for serious health impacts to exposed workers; including the potential for lung cancer and adverse irritant and cardiovascular effects. Personal respiratory protective devices are an accepted safety measure to mitigate worker exposure against the potentially damaging health impacts of DPM. To be protective, they need to act as effective filters against carbon and other particulates. In Australia, the filtering efficiency of respiratory protective devices is determined by challenging test filter media with aerosolised sodium chloride to determine penetration at designated flow rates. The methodology outlined in AS/NZS1716 (Standards Australia International Ltd and Standards New Zealand 2012. Respiratory protective devices. Sydney/Wellington: SAI Global Limited/Standards New Zealand) does not account for the differences between characteristics of workplace contaminants like DPM and sodium chloride such as structure, composition, and particle size. This study examined filtering efficiency for three commonly used AS/NZS certified respirator filter models, challenging them with two types of diesel emissions; those from a diesel generator and a diesel engine. Penetration through the filter media of elemental carbon (EC), total carbon (TC), and total suspended particulate (TSP) was calculated. Results indicate that filtering efficiency assumed by P2 certification in Australia was achieved for two of the three respirator models for DPM generated using the small diesel generator, whilst when the larger diesel engine was used, filtering efficiency requirements were met for all three filter models. These results suggest that the testing methodology specified for certification of personal respiratory protective devices by Standards Australia may not ensure adequate protection for

  11. Electrostatic N-95 respirator filter media efficiency degradation resulting from intermittent sodium chloride aerosol exposure.

    PubMed

    Moyer, E S; Bergman, M S

    2000-08-01

    The effects of intermittently loading small masses of sodium chloride aerosol on the filtration efficiency of N-95 filtering facepiece respirators was investigated. The National Institute for Occupational Safety and Health (NIOSH) certifies that N-95 respirators must provide at least 95 percent filtration efficiency against a sodium chloride aerosol challenge as per the respirator certification (42 CFR 84) test criteria. N-95 respirators are specified for protection against solid and water-based particulates (i.e., non-oil aerosols). New N-95 respirators from three different manufacturers were loaded with 5 +/- 1 mg of sodium chloride aerosol one day a week, over a period of weeks. Aerosol loading and penetration measurements were performed using the TSI 8130 Filter Tester. Respirators were stored uncovered on an office desktop outside the laboratory. To investigate environmental and temporal effects of filters being stored without sodium chloride exposure, control respirators were stored on the desk for various lengths of time before being initiated into weekly testing. For all manufacturers' respirators, the controls showed similar initial penetrations on their day of initiation (day zero) to those of the study samples on day zero. As the controls were tested weekly, they showed similar degradation rates to those of the study samples. Results show that some of the manufacturers' models had penetrations of greater than 5 percent when intermittently exposed to sodium chloride aerosol. It is concluded that intermittent, low-level sodium chloride aerosol loading of N-95 respirators has a degrading effect on filter efficiency. This reduction in filter efficiency was not accompanied by a significant increase in breathing resistance that would signal the user that the filter needs to be replaced. Furthermore, it was noted that the effect of room storage time prior to initial exposure was much less significant.

  12. Penetration of Fiber Versus Spherical Particles Through Filter Media and Faceseal Leakage of N95 Filtering Facepiece Respirators with Cyclic Flow

    PubMed Central

    Cho, Kyungmin Jacob; Turkevich, Leonid; Miller, Matthew; McKay, Roy; Grinshpun, Sergey A.; Ha, KwonChul; Reponen, Tiina

    2015-01-01

    This study investigated differences in penetration between fibers and spherical particles through faceseal leakage of an N95 filtering facepiece respirator. Three cyclic breathing flows were generated corresponding to mean inspiratory flow rates (MIF) of 15, 30, and 85 L/min. Fibers had a mean diameter of 1 μm and a median length of 4.9 μm (calculated aerodynamic diameter, dae = 1.73 μm). Monodisperse polystyrene spheres with a mean physical diameter of 1.01 μm (PSI) and 1.54 μm (PSII) were used for comparison (calculated dae = 1.05 and 1.58 μm, respectively). Two optical particle counters simultaneously determined concentrations inside and outside the respirator. Geometric means (GMs) for filter penetration of the fibers were 0.06, 0.09, and 0.08% at MIF of 15, 30, and 85 L/min, respectively. Corresponding values for PSI were 0.07, 0.12, and 0.12%. GMs for faceseal penetration of fibers were 0.40, 0.14, and 0.09% at MIF of 15, 30, and 85 L/min, respectively. Corresponding values for PSI were 0.96, 0.41, and 0.17%. Faceseal penetration decreased with increased breathing rate for both types of particles (p ≤ 0.001). GMs of filter and faceseal penetration of PSII at an MIF of 30 L/min were 0.14% and 0.36%, respectively. Filter penetration and faceseal penetration of fibers were significantly lower than those of PSI (p < 0.001) and PSII (p < 0.003). This confirmed that higher penetration of PSI was not due to slightly smaller aerodynamic diameter, indicating that the shape of fibers rather than their calculated mean aerodynamic diameter is a prevailing factor on deposition mechanisms through the tested respirator. In conclusion, faceseal penetration of fibers and spherical particles decreased with increasing breathing rate, which can be explained by increased capture by impaction. Spherical particles had 2.0–2.8 times higher penetration through faceseal leaks and 1.1–1.5 higher penetration through filter media than fibers, which can be attributed to

  13. Penetration of fiber versus spherical particles through filter media and faceseal leakage of N95 filtering facepiece respirators with cyclic flow.

    PubMed

    Cho, Kyungmin Jacob; Turkevich, Leonid; Miller, Matthew; McKay, Roy; Grinshpun, Sergey A; Ha, KwonChul; Reponen, Tiina

    2013-01-01

    This study investigated differences in penetration between fibers and spherical particles through faceseal leakage of an N95 filtering facepiece respirator. Three cyclic breathing flows were generated corresponding to mean inspiratory flow rates (MIF) of 15, 30, and 85 L/min. Fibers had a mean diameter of 1 μm and a median length of 4.9 μm (calculated aerodynamic diameter, d(ae) = 1.73 μm). Monodisperse polystyrene spheres with a mean physical diameter of 1.01 μm (PSI) and 1.54 μm (PSII) were used for comparison (calculated d(ae) = 1.05 and 1.58 μm, respectively). Two optical particle counters simultaneously determined concentrations inside and outside the respirator. Geometric means (GMs) for filter penetration of the fibers were 0.06, 0.09, and 0.08% at MIF of 15, 30, and 85 L/min, respectively. Corresponding values for PSI were 0.07, 0.12, and 0.12%. GMs for faceseal penetration of fibers were 0.40, 0.14, and 0.09% at MIF of 15, 30, and 85 L/min, respectively. Corresponding values for PSI were 0.96, 0.41, and 0.17%. Faceseal penetration decreased with increased breathing rate for both types of particles (p ≤ 0.001). GMs of filter and faceseal penetration of PSII at an MIF of 30 L/min were 0.14% and 0.36%, respectively. Filter penetration and faceseal penetration of fibers were significantly lower than those of PSI (p < 0.001) and PSII (p < 0.003). This confirmed that higher penetration of PSI was not due to slightly smaller aerodynamic diameter, indicating that the shape of fibers rather than their calculated mean aerodynamic diameter is a prevailing factor on deposition mechanisms through the tested respirator. In conclusion, faceseal penetration of fibers and spherical particles decreased with increasing breathing rate, which can be explained by increased capture by impaction. Spherical particles had 2.0-2.8 times higher penetration through faceseal leaks and 1.1-1.5 higher penetration through filter media than fibers, which can be attributed to

  14. 77 FR 68784 - Standard Test Procedures Approval Process for Respirators To Be Used in Wildland Fire-Fighting...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-16

    ... regulations allow. Because manufacturers have not yet developed respiratory protection for this occupational...-approved filtering facepiece respirators which are not designed for this use, or no respiratory protection... respiratory protective devices designed for the inhalation hazards of this occupational setting. On July 10...

  15. Respirable particulate monitoring with remote sensors. (Public health ecology: Air pollution)

    NASA Technical Reports Server (NTRS)

    Severs, R. K.

    1974-01-01

    The feasibility of monitoring atmospheric aerosols in the respirable range from air or space platforms was studied. Secondary reflectance targets were located in the industrial area and near Galveston Bay. Multichannel remote sensor data were utilized to calculate the aerosol extinction coefficient and thus determine the aerosol size distribution. Houston Texas air sampling network high volume data were utilized to generate computer isopleth maps of suspended particulates and to establish the mass loading of the atmosphere. In addition, a five channel nephelometer and a multistage particulate air sampler were used to collect data. The extinction coefficient determined from remote sensor data proved more representative of wide areal phenomena than that calculated from on site measurements. It was also demonstrated that a significant reduction in the standard deviation of the extinction coefficient could be achieved by reducing the bandwidths used in remote sensor.

  16. [Filtering facepieces: effect of oily aerosol load on penetration through the filtering material].

    PubMed

    Plebani, Carmela; Listrani, S; Di Luigi, M

    2010-01-01

    Electrostatic filters are widely used in applications requiring high filtration efficiency and low pressure drop. However various studies showed that the penetration through electrostatic filters increases during exposure to an aerosol flow. This study investigates the effects of prolonged exposure to an oily aerosol on the penetration through filtering facepieces available on the market. Some samples of FFP1, FFP2 and FFP3 filtering facepieces were exposed for 8 hours consecutively to a paraffin oil polydisperse aerosol. At the end of the exposure about 830 mg of paraffin oil were deposited in the facepiece. All the examined facepieces showed penetration values that increased with paraffin oil load while pressure drop values were substantially the same before and after exposure. The measured maximum penetration values did not exceed the maximum penetration values allowed by the European technical standards, except in one case. According to the literature, 830 mg of oil load in a facepiece is not feasible in workplaces over an eight- hour shift. However, the trend of the penetration versus exposure mass suggests that if the load increases, the penetration may exceed the maximum allowed values. For comparison a mechanical filter was also studied. This showed an initial pressure drop higher than FFP2 filtering facepieces characterized by comparable penetration values. During exposure the pressure drop virtually doubled while penetration did not change. The increase in penetration with no increase in pressure drop in the analyzed facepieces indicates that it is necessary to comply with the information supplied by the manufacturer that restricts their use to a single shift.

  17. Effect of Pregnancy Upon Facial Anthropometrics and Respirator Fit Testing.

    PubMed

    Roberge, Raymond J; Kim, Jung-Hyun; Palmiero, Andrew; Powell, Jeffrey B

    2015-01-01

    Workers required to wear respirators must undergo additional respirator fit testing if a significant change in body weight occurs. Approximately 10% of working women of reproductive age will be pregnant and experience a significant change in weight, yet the effect of pregnancy-associated weight gain on respirator fit is unknown. Cephalo-facial anthropometric measurements and quantitative fit testing of N95 filtering facepiece respirators (N95 FFR) of 15 pregnant women and 15 matched, non-pregnant women were undertaken for comparisons between the groups. There were no significant differences between pregnant and non-pregnant women with respect to cephalo-facial anthropometric measurements or N95 FFR quantitative fit tests. Healthy pregnant workers, who adhere to the recommended weight gain limits of pregnancy, are unlikely to experience an increase in cephalo-facial dimensions that would mandate additional N95 FFR fit testing above that which is normally required on an annual basis.

  18. Comfort and exertion while using filtering facepiece respirators with exhalation valve and an active venting system among male military personnel.

    PubMed

    Seng, Melvin; Wee, Liang En; Zhao, Xiahong; Cook, Alex R; Chia, Sin Eng; Lee, Vernon J

    2017-07-06

    This study aimed to determine if disposable filtering facepiece respirators (FFRs), with exhalation valve (EV) and a novel active venting system (AVS), provided greater perceived comfort and exertion when compared to standard N95 FFRs without these features among male military personnel performing prolonged essential outdoor duties. We used a randomised open-label controlled crossover study design to compare three FFR options: (a) standard FFR; (b) FFR with EV; and (c) FFR with EV+AVS. Male military personnel aged between 18 and 20 years completed a questionnaire at the beginning (baseline), after two hours of standardised non-strenuous outdoor duty and after 12 hours of duty divided into two-hour work-rest cycles. Participants rated the degree of discomfort, exertion and symptoms using a five-point Likert scale. The association between outcomes and the types of FFR was assessed using a multivariate ordered probit mixed-effects model. For a majority of the symptoms, study participants rated FFR with EV and FFR with EV+AVS with significantly better scores than standard FFR. Both FFR with EV and FFR with EV+AVS had significantly less discomfort (FFR with EV+AVS: 91.1%; FFR with EV: 57.6%) and exertion (FFR with EV+AVS: 83.5%; FFR with EV: 34.4%) than standard FFR. FFR with EV+AVS also had significantly better scores for exertion (53.4%) and comfort (39.4%) when compared to FFR with EV. Usage of FFR with EV+AVS resulted in significantly reduced symptoms, discomfort and exertion when compared to FFR with EV and standard FFR.

  19. The effect of facial expressions on respirators contact pressures.

    PubMed

    Cai, Mang; Shen, Shengnan; Li, Hui

    2017-08-01

    This study investigated the effect of four typical facial expressions (calmness, happiness, sadness and surprise) on contact characteristics between an N95 filtering facepiece respirator and a headform. The respirator model comprised two layers (an inner layer and an outer layer) and a nose clip. The headform model was comprised of a skin layer, a fatty tissue layer embedded with eight muscles, and a skull layer. Four typical facial expressions were generated by the coordinated contraction of four facial muscles. After that, the distribution of the contact pressure on the headform, as well as the contact area, were calculated. Results demonstrated that the nasal clip could help make the respirator move closer to the nose bridge while causing facial discomfort. Moreover, contact areas varied with different facial expressions, and facial expressions significantly altered contact pressures at different key areas, which may result in leakage.

  20. Commentary Considerations for Recommending Extended Use and Limited Reuse of Filtering Facepiece Respirators in Health Care Settings

    PubMed Central

    Fisher, Edward M.; Shaffer, Ronald E.

    2015-01-01

    Public health organizations, such as the Centers for Disease Control and Prevention (CDC), are increasingly recommending the use of N95 filtering facepiece respirators (FFRs) in health care settings. For infection control purposes, the usual practice is to discard FFRs after close contact with a patient (“single use”). However, in some situations, such as during contact with tuberculosis patients, limited FFR reuse (i.e., repeated donning and doffing of the same FFR by the same person) is practiced. A related practice, extended use, involves wearing the same FFR for multiple patient encounters without doffing. Extended use and limited FFR reuse have been recommended during infectious disease outbreaks and pandemics to conserve FFR supplies. This commentary examines CDC recommendations related to FFR extended use and limited reuse and analyzes available data from the literature to provide a relative estimate of the risks of these practices compared to single use. Analysis of the available data and the use of disease transmission models indicate that decisions regarding whether FFR extended use or reuse should be recommended should continue to be pathogen- and event-specific. Factors to be included in developing the recommendations are the potential for the pathogen to spread via contact transmission, the potential that the event could result in or is currently causing a FFR shortage, the protection provided by FFR use, human factors, potential for self-inoculation, the potential for secondary exposures, and government policies and regulations. While recent findings largely support the previous recommendations for extended use and limited reuse in certain situations, some new cautions and limitations should be considered before issuing recommendations in the future. In general, extended use of FFRs is preferred over limited FFR reuse. Limited FFR reuse would allow the user a brief respite from extended wear times, but increases the risk of self-inoculation and

  1. Analysis of respirable particulate exposure and its effect to public health around lead smelter and e-waste processing industry in West Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Marselina, M.; Roosmini, D.; Salami, I. R. S.; Ayu A, M.; Cahyadi, W.

    2016-03-01

    Respirable particulate exposure strongly affects human health, especially for children who lived around industrial area. This study was conducted to evaluate the effect of respirable particulate exposure to lung capacity of children. Study location in this study was Parung Panjang District, area of lead smelter industry and also in Astana Anyar District, area of e-waste processing industry. Thirty children were involved in Astana Anyar District and also thirty children in Parung Panjang District. The control groups were also studied in both areas. Predicted average daily intake (ADD) of respirable particulate was estimated and lung or respiration condition of children was measured by using spirometer. The lung condition of respondents was estimated by FEV1.0 and FVC values. As the result, the predicted ADD of children in lead smelter area is 3 times higher than the predicted ADD of children in e-waste processing area. It was correlated positively with the higher PM2.5 concentration in Parung Panjang District than the PM2.5 concentration in Astana Anyar District. Metals concentration in Parung Panjang was also measured with X-Ray Fluorescence (XRF) in this study and it was clearly state that metals concentration in location study were higher than metals concentration in control area.

  2. Quantitative exposure matrix for asphalt fume, total particulate matter, and respirable crystalline silica among roofing and asphalt manufacturing workers.

    PubMed

    Fayerweather, William E; Trumbore, David C; Johnson, Kathleen A; Niebo, Ronald W; Maxim, L Daniel

    2011-09-01

    This paper summarizes available data on worker exposures to asphalt fume (soluble fraction), total particulate matter, and respirable crystalline silica (quartz) [hereinafter RCS] over a 30-year period in Owens Corning's asphalt production and roofing manufacturing plants. For the period 1977 through 2006, the air-monitoring database contains more than 1,400 personal samples for asphalt fume (soluble fraction), 2,400 personal samples for total particulate, and 1,300 personal samples for RCS. Unique process-job categories were identified for the asphalt production and roofing shingle manufacturing plants. Quantitative exposures were tabulated by agent, process-job, and calendar period to form an exposure matrix for use in subsequent epidemiologic studies of the respiratory health of these workers. Analysis of time trends in exposure data shows substantial and statistically significant exposure reductions for asphalt fume (soluble fraction), total particulate matter, and respirable crystalline silica at Owens Corning plants. Cumulative distribution plots for the most recent sampling period (2001-2006) show that 95% of the asphalt fume (soluble fraction) measurements were less than 0.25 mg/m3; 95% of the total particulate measurements were less than 2.2 mg/m3; and 95% of the RCS measurements were less than 0.05 mg/m3. Several recommendations are offered to improve the design of future monitoring efforts.

  3. 42 CFR 84.174 - Respirator containers; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Air-Purifying Particulate Respirators § 84.174 Respirator containers; minimum requirements. (a) Except... contamination of respirators which are not removed, and to prevent damage to respirators during transit. ...

  4. Workplace field testing of the pressure drop of particulate respirators using welding fumes.

    PubMed

    Cho, Hyun-Woo; Yoon, Chung-Sik

    2012-10-01

    In a previous study, we concluded that respirator testing with a sodium chloride aerosol gave a conservative estimate of filter penetration for welding fume aerosols. A rapid increase in the pressure drop (PD) of some respirators was observed as fumes accumulated on the filters. The present study evaluated particulate respirator PD based on workplace field tests. A field PD tester was designed and validated using the TSI 8130 Automatic Filter Tester, designed in compliance with National Institute for Occupational and Safety and Health regulation 42 CFR part 84. Three models (two replaceable dual-type filters and one replaceable single-type filter) were evaluated against CO(2) gas arc welding on mild steel in confined booths in the workplace. Field tests were performed under four airborne concentrations (27.5, 15.4, 7.9, and 2.1 mg m(-3)). The mass concentration was measured by the gravimetric method, and number concentration was monitored using P-Trak (Model 8525, TSI, USA). Additionally, photos and scanning electron microscopy-energy dispersive X-ray spectroscopy were used to visualize and analyze the composition of welding fumes trapped in the filters. The field PD tester showed no significant difference compared with the TSI tester. There was no significant difference in the initial PD between laboratory and field results. The PD increased as a function of fume load on the respirator filters for all tested models. The increasing PD trend differed by models, and PD increased rapidly at high concentrations because greater amount of fumes accumulated on the filters in a given time. The increase in PD as a function of fume load on the filters showed a similar pattern as fume load varied for a particular model, but different patterns were observed for different models. Images and elemental analyses of fumes trapped on the respirator filters showed that most welding fumes were trapped within the first layer, outer web cover, and second layer, in order, while no fumes

  5. Polycyclic aromatic hydrocarbons and their molecular diagnostic ratios in urban atmospheric respirable particulate matter

    NASA Astrophysics Data System (ADS)

    del Rosario Sienra, María; Rosazza, Nelson G.; Préndez, Margarita

    2005-06-01

    Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) in Santiago de Chile city were evaluated to study particulate PAHs profiles during cold and spring weather periods. Urban atmospheric particulate matter PM10 was collected using High Volume PM10 samplers. Fifteen samples of 24 h during austral winter and 20 samples of 24 h during spring, 2000 were collected at two sampling sites (North-East and Central areas of the city) whose characteristics were representative of the prevailing conditions. Seventeen PAHs were quantified and total PAHs concentration ranged from 1.39 to 59.98 ng m -3, with a seasonal variation (winter vs. spring ratio) from 0.5 to 12.6 ng m -3. Molecular diagnostic ratios were used to characterize and identify PAHs emission sources such as combustion and biogenic emissions. Results showed that the major sources of respirable organic aerosol PM10 in Santiago are mobile and stationary ones.

  6. Particle Size-Selective Assessment of Protection of European Standard FFP Respirators and Surgical Masks against Particles-Tested with Human Subjects

    PubMed Central

    Hwang, Dong-Chir; Li, He-Yi; Tsai, Chieh-Fu; Chen, Chun-Wan; Chen, Jen-Kun

    2016-01-01

    This study was conducted to investigate the protection of disposable filtering half-facepiece respirators of different grades against particles between 0.093 and 1.61 μm. A personal sampling system was used to particle size-selectively assess the protection of respirators. The results show that about 10.9% of FFP2 respirators and 28.2% of FFP3 respirators demonstrate assigned protection factors (APFs) below 10 and 20, which are the levels assigned for these respirators by the British Standard. On average, the protection factors of FFP respirators were 11.5 to 15.9 times greater than those of surgical masks. The minimum protection factors (PFs) were observed for particles between 0.263 and 0.384 μm. No significant difference in PF results was found among FFP respirator categories and particle size. A strong association between fit factors and protection factors was found. The study indicates that FFP respirators may not achieve the expected protection level and the APFs may need to be revised for these classes of respirators. PMID:27195721

  7. 42 CFR 84.76 - Facepieces; eyepieces; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Facepieces; eyepieces; minimum requirements. 84.76 Section 84.76 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

  8. 42 CFR 84.76 - Facepieces; eyepieces; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Facepieces; eyepieces; minimum requirements. 84.76 Section 84.76 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

  9. 42 CFR 84.76 - Facepieces; eyepieces; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Facepieces; eyepieces; minimum requirements. 84.76 Section 84.76 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

  10. 42 CFR 84.76 - Facepieces; eyepieces; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Facepieces; eyepieces; minimum requirements. 84.76 Section 84.76 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

  11. 42 CFR 84.76 - Facepieces; eyepieces; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Facepieces; eyepieces; minimum requirements. 84.76 Section 84.76 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

  12. Comparison of performance of three different types of respiratory protection devices.

    PubMed

    Lawrence, Robert B; Duling, Matthew G; Calvert, Catherine A; Coffey, Christopher C

    2006-09-01

    Respiratory protection is offered to American workers in a variety of ways to guard against potential inhalation hazards. Two of the most common ways are elastomeric N95 respirators and N95 filtering-facepiece respirators. Some in the health care industry feel that surgical masks provide an acceptable level of protection in certain situations against particular hazards. This study compared the performance of these types of respiratory protection during a simulated workplace test that measured both filter penetration and face-seal leakage. A panel of 25 test subjects with varying face sizes tested 15 models of elastomeric N95 respirators, 15 models of N95 filtering-facepiece respirators, and 6 models of surgical masks. Simulated workplace testing was conducted using a TSI PORTACOUNT Plus model 8020, and consisted of a series of seven exercises. Six simulated workplace tests were performed with redonning of the respirator/mask occurring between each test. The results of these tests produced a simulated workplace protection factor (SWPF). The geometric mean (GM) and the 5th percentile values of the SWPFs were computed by category of respiratory protection using the six overall SWPF values. The level of protection provided by each of the three respiratory protection types was compared. The GM and 5th percentile SWPF values without fit testing were used for the comparison, as surgical masks were not intended to be fit tested. The GM values were 36 for elastomeric N95 respirators, 21 for N95 filtering-facepiece respirators, and 3 for surgical masks. An analysis of variance demonstrated a statistically significant difference between all three. Elastomeric N95 respirators had the highest 5th percentile SWPF of 7. N95 filtering-facepiece respirators and surgical masks had 5th percentile SWPFs of 3 and 1, respectively. A Fisher Exact Test revealed that the 5th percentile SWPFs for all three types of respiratory protection were statistically different. In addition, both

  13. 42 CFR 84.124 - Facepiece tests; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Facepiece tests; minimum requirements. 84.124 Section 84.124 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks...

  14. 42 CFR 84.124 - Facepiece tests; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Facepiece tests; minimum requirements. 84.124 Section 84.124 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks...

  15. 42 CFR 84.124 - Facepiece tests; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Facepiece tests; minimum requirements. 84.124 Section 84.124 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks...

  16. 42 CFR 84.119 - Facepieces; eyepieces; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Facepieces; eyepieces; minimum requirements. 84.119 Section 84.119 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks...

  17. 42 CFR 84.119 - Facepieces; eyepieces; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Facepieces; eyepieces; minimum requirements. 84.119 Section 84.119 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks...

  18. 42 CFR 84.124 - Facepiece tests; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Facepiece tests; minimum requirements. 84.124 Section 84.124 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks...

  19. 42 CFR 84.119 - Facepieces; eyepieces; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Facepieces; eyepieces; minimum requirements. 84.119 Section 84.119 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks...

  20. 42 CFR 84.119 - Facepieces; eyepieces; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Facepieces; eyepieces; minimum requirements. 84.119 Section 84.119 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks...

  1. 42 CFR 84.119 - Facepieces; eyepieces; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Facepieces; eyepieces; minimum requirements. 84.119 Section 84.119 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks...

  2. 42 CFR 84.124 - Facepiece tests; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Facepiece tests; minimum requirements. 84.124 Section 84.124 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks...

  3. Respirator Performance against Nanoparticles under Simulated Workplace Activities

    PubMed Central

    Vo, Evanly; Zhuang, Ziqing; Horvatin, Matthew; Liu, Yuewei; He, Xinjian; Rengasamy, Samy

    2017-01-01

    Filtering facepiece respirators (FFRs) and elastomeric half-mask respirators (EHRs) are commonly used by workers for protection against potentially hazardous particles, including engineered nanoparticles. The purpose of this study was to evaluate the performance of these types of respirators against 10–400 nm particles using human subjects exposed to NaCl aerosols under simulated workplace activities. Simulated workplace protection factors (SWPFs) were measured for eight combinations of respirator models (2 N95 FFRs, 2 P100 FFRs, 2 N95 EHRs, and 2 P100 EHRs) worn by 25 healthy test subjects (13 females and 12 males) with varying face sizes. Before beginning a SWPF test for a given respirator model, each subject had to pass a quantitative fit test. Each SWPF test was performed using a protocol of six exercises for 3 min each: (i) normal breathing, (ii) deep breathing, (iii) moving head side to side, (iv) moving head up and down, (v) bending at the waist, and (vi) a simulated laboratory-vessel cleaning motion. Two scanning mobility particle sizers were used simultaneously to measure the upstream (outside the respirator) and downstream (inside the respirator) test aerosol; SWPF was then calculated as a ratio of the upstream and downstream particle concentrations. In general, geometric mean SWPF (GM-SWPF) was highest for the P100 EHRs, followed by P100 FFRs, N95 EHRs, and N95 FFRs. This trend holds true for nanoparticles (10–100 nm), larger size particles (100–400 nm), and the ‘all size’ range (10–400 nm). All respirators provided better or similar performance levels for 10–100 nm particles as compared to larger 100–400 nm particles. This study found that class P100 respirators provided higher SWPFs compared to class N95 respirators (P<0.05) for both FFR and EHR types. All respirators provided expected performance (i.e. fifth percentile SWPF > 10) against all particle size ranges tested. PMID:26180261

  4. An Evaluation of Sharp Cut Cyclones for Sampling Diesel Particulate Matter Aerosol in the Presence of Respirable Dust

    PubMed Central

    Cauda, Emanuele; Sheehan, Maura; Gussman, Robert; Kenny, Lee; Volkwein, Jon

    2015-01-01

    Two prototype cyclones were the subjects of a comparative research campaign with a diesel particulate matter sampler (DPMS) that consists of a respirable cyclone combined with a downstream impactor. The DPMS is currently used in mining environments to separate dust from the diesel particulate matter and to avoid interferences in the analysis of integrated samples and direct-reading monitoring in occupational environments. The sampling characteristics of all three devices were compared using ammonium fluorescein, diesel, and coal dust aerosols. With solid spherical test aerosols at low particle loadings, the aerodynamic size-selection characteristics of all three devices were found to be similar, with 50% penetration efficiencies (d50) close to the design value of 0.8 µm, as required by the US Mine Safety and Health Administration for monitoring occupational exposure to diesel particulate matter in US mining operations. The prototype cyclones were shown to have ‘sharp cut’ size-selection characteristics that equaled or exceeded the sharpness of the DPMS. The penetration of diesel aerosols was optimal for all three samplers, while the results of the tests with coal dust induced the exclusion of one of the prototypes from subsequent testing. The sampling characteristics of the remaining prototype sharp cut cyclone (SCC) and the DPMS were tested with different loading of coal dust. While the characteristics of the SCC remained constant, the deposited respirable coal dust particles altered the size-selection performance of the currently used sampler. This study demonstrates that the SCC performed better overall than the DPMS. PMID:25060240

  5. The effect of high-efficiency particulate air respirator design on occupational health: a pilot study balancing risks in the real world.

    PubMed

    Eck, E K; Vannier, A

    1997-02-01

    To quantify specific factors believed to increase healthcare worker (HCW) risk for contaminated sharps injuries (eg, visibility, communication, and range of motion); to quantify the degree to which respirators of various designs impacted those same factors; and to assess HCW opinions about the suitability of selected respirators with respect to patient care and user compliance criteria. Sharps injury data from seven hospitals were analyzed to determine the potential contribution of visibility, communication, and range of motion to reported injuries. Healthcare workers representing various clinical specialties and physical characteristics were examined at baseline and while wearing five different respirators to quantify the impact of respirator design on visibility, communication, and range of motion. Healthcare workers were interviewed and completed a survey assessing each respirator. Hospital and ambulatory-care settings. Population-based and convenience sample. Communication, visibility, and range of motion were found to affect contaminated sharps injuries significantly. Selected high-efficiency particulate air (HEPA) respirators were found to have a negative impact on each of these variables. Healthcare workers involved in the study also reported compliance criteria problems with selected HEPA respirators, which may effect implementation of respiratory precautions adversely. Current HEPA respirators, because of their design, potentially increase the risk of bloodborne pathogen exposure through sharps injuries. We conclude that mandating respirators without regard to the potential impact of their design to the sharps injuries may be counterproductive to HCW safety, because they may increase, rather than decrease, overall occupational risk to HCWs.

  6. 42 CFR 84.136 - Facepieces, hoods, and helmets; eyepieces; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... (a) Facepieces, hoods, and helmets shall be designed and constructed to provide adequate vision which... suitable material which does not interfere with the vision of the wearer. (2) Shields shall be mounted and...

  7. 42 CFR 84.136 - Facepieces, hoods, and helmets; eyepieces; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... (a) Facepieces, hoods, and helmets shall be designed and constructed to provide adequate vision which... suitable material which does not interfere with the vision of the wearer. (2) Shields shall be mounted and...

  8. N95 respirator use during advanced pregnancy.

    PubMed

    Roberge, Raymond J; Kim, Jung-Hyun; Powell, Jeffrey B

    2014-10-01

    To determine the physiological and subjective effects of wearing an N95 filtering facepiece respirator (N95 FFR) in advanced stages of pregnancy. Healthy pregnant women (n = 22) and nonpregnant women (n = 22) had physiological and subjective measurements taken with and without wearing an N95 FFR during exercise and postural sedentary activities over a 1-hour period. There were no differences between the pregnant and nonpregnant women with respect to heart rate, respiratory rate, oxygen saturation, transcutaneous carbon dioxide level, chest wall temperature, aural temperature, and subjective perceptions of exertion and thermal comfort. No significant effect on fetal heart rate was noted. Healthy pregnant women wearing an N95 FFR for 1 hour during exercise and sedentary activities did not exhibit any significant differences in measured physiological and subjective responses compared with nonpregnant women. Published by Elsevier Inc.

  9. The use of high-efficiency particulate air-filter respirators to protect hospital workers from tuberculosis. A cost-effectiveness analysis.

    PubMed

    Adal, K A; Anglim, A M; Palumbo, C L; Titus, M G; Coyner, B J; Farr, B M

    1994-07-21

    After outbreaks of multidrug-resistant tuberculosis, the Centers for Disease Control and Prevention proposed the use of respirators with high-efficiency particulate air filters (HEPA respirators) as part of isolation precautions against tuberculosis, along with a respiratory-protection program for health care workers that includes medical evaluation, training, and tests of the fit of the respirators. Each HEPA respirator costs between $7.51 and $9.08, about 10 times the cost of respirators currently used. We conducted a cost-effectiveness analysis using data from the University of Virginia Hospital on exposure to patients with tuberculosis and rates at which the purified-protein-derivative (PPD) skin test became positive in hospital workers. The costs of a respiratory-protection program were based on those of an existing program for workers dealing with hazardous substances. During 1992, 11 patients with documented tuberculosis were admitted to our hospital. Eight of 3852 workers (0.2 percent) had PPD tests that became positive. Five of these conversions were believed to be due to the booster phenomenon; one followed unprotected exposure to a patient not yet in isolation; the other two occurred in workers who had never entered a tuberculosis isolation room. These data suggest that it will take more than one year for the use of HEPA respirators to prevent a single conversion of the PPD test. Assuming that one conversion is prevented per year, however, it would take 41 years at out hospital to prevent one case of occupationally acquired tuberculosis, at a cost of $1.3 million to $18.5 million. Given the effectiveness of currently recommended measures to prevent nosocomial transmission of tuberculosis, the addition of HEPA respirators would offer negligible protective efficacy at great cost.

  10. 42 CFR 84.1136 - Facepieces, hoods, and helmets; eyepieces; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Facepieces, hoods, and helmets; eyepieces; minimum requirements. 84.1136 Section 84.1136 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

  11. 42 CFR 84.1136 - Facepieces, hoods, and helmets; eyepieces; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Facepieces, hoods, and helmets; eyepieces; minimum requirements. 84.1136 Section 84.1136 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

  12. 42 CFR 84.1136 - Facepieces, hoods, and helmets; eyepieces; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Facepieces, hoods, and helmets; eyepieces; minimum requirements. 84.1136 Section 84.1136 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

  13. 42 CFR 84.1136 - Facepieces, hoods, and helmets; eyepieces; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Facepieces, hoods, and helmets; eyepieces; minimum requirements. 84.1136 Section 84.1136 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

  14. 42 CFR 84.1136 - Facepieces, hoods, and helmets; eyepieces; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Facepieces, hoods, and helmets; eyepieces; minimum requirements. 84.1136 Section 84.1136 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

  15. 42 CFR 84.130 - Supplied-air respirators; description.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... material to protect the window(s) of facepieces, hoods, and helmets which do not unduly interfere with the wearer's vision and permit easy access to the external surface of such window(s) for cleaning. (c) Type..., glass, woven wire, sheet metal, or other suitable material to protect the window(s) of facepieces, hoods...

  16. A Novel Algorithm for Determining Contact Area Between a Respirator and a Headform

    PubMed Central

    Lei, Zhipeng; Yang, James; Zhuang, Ziqing

    2016-01-01

    The contact area, as well as the contact pressure, is created when a respiratory protection device (a respirator or surgical mask) contacts a human face. A computer-based algorithm for determining the contact area between a headform and N95 filtering facepiece respirator (FFR) was proposed. Six N95 FFRs were applied to five sizes of standard headforms (large, medium, small, long/narrow, and short/wide) to simulate respirator donning. After the contact simulation between a headform and an N95 FFR was conducted, a contact area was determined by extracting the intersection surfaces of the headform and the N95 FFR. Using computer-aided design tools, a superimposed contact area and an average contact area, which are non-uniform rational basis spline (NURBS) surfaces, were developed for each headform. Experiments that directly measured dimensions of the contact areas between headform prototypes and N95 FFRs were used to validate the simulation results. Headform sizes influenced all contact area dimensions (P < 0.0001), and N95 FFR sizing systems influenced all contact area dimensions (P < 0.05) except the left and right chin regions. The medium headform produced the largest contact area, while the large and small headforms produced the smallest. PMID:24579752

  17. A novel algorithm for determining contact area between a respirator and a headform.

    PubMed

    Lei, Zhipeng; Yang, James; Zhuang, Ziqing

    2014-01-01

    The contact area, as well as the contact pressure, is created when a respiratory protection device (a respirator or surgical mask) contacts a human face. A computer-based algorithm for determining the contact area between a headform and N95 filtering facepiece respirator (FFR) was proposed. Six N95 FFRs were applied to five sizes of standard headforms (large, medium, small, long/narrow, and short/wide) to simulate respirator donning. After the contact simulation between a headform and an N95 FFR was conducted, a contact area was determined by extracting the intersection surfaces of the headform and the N95 FFR. Using computer-aided design tools, a superimposed contact area and an average contact area, which are non-uniform rational basis spline (NURBS) surfaces, were developed for each headform. Experiments that directly measured dimensions of the contact areas between headform prototypes and N95 FFRs were used to validate the simulation results. Headform sizes influenced all contact area dimensions (P < 0.0001), and N95 FFR sizing systems influenced all contact area dimensions (P < 0.05) except the left and right chin regions. The medium headform produced the largest contact area, while the large and small headforms produced the smallest.

  18. Health Outcomes of Exposure to Biological and Chemical Components of Inhalable and Respirable Particulate Matter.

    PubMed

    Morakinyo, Oyewale Mayowa; Mokgobu, Matlou Ingrid; Mukhola, Murembiwa Stanley; Hunter, Raymond Paul

    2016-06-14

    Particulate matter (PM) is a key indicator of air pollution and a significant risk factor for adverse health outcomes in humans. PM is not a self-contained pollutant but a mixture of different compounds including chemical and biological fractions. While several reviews have focused on the chemical components of PM and associated health effects, there is a dearth of review studies that holistically examine the role of biological and chemical components of inhalable and respirable PM in disease causation. A literature search using various search engines and (or) keywords was done. Articles selected for review were chosen following predefined criteria, to extract and analyze data. The results show that the biological and chemical components of inhalable and respirable PM play a significant role in the burden of health effects attributed to PM. These health outcomes include low birth weight, emergency room visit, hospital admission, respiratory and pulmonary diseases, cardiovascular disease, cancer, non-communicable diseases, and premature death, among others. This review justifies the importance of each or synergistic effects of the biological and chemical constituents of PM on health. It also provides information that informs policy on the establishment of exposure limits for PM composition metrics rather than the existing exposure limits of the total mass of PM. This will allow for more effective management strategies for improving outdoor air quality.

  19. Health Outcomes of Exposure to Biological and Chemical Components of Inhalable and Respirable Particulate Matter

    PubMed Central

    Morakinyo, Oyewale Mayowa; Mokgobu, Matlou Ingrid; Mukhola, Murembiwa Stanley; Hunter, Raymond Paul

    2016-01-01

    Particulate matter (PM) is a key indicator of air pollution and a significant risk factor for adverse health outcomes in humans. PM is not a self-contained pollutant but a mixture of different compounds including chemical and biological fractions. While several reviews have focused on the chemical components of PM and associated health effects, there is a dearth of review studies that holistically examine the role of biological and chemical components of inhalable and respirable PM in disease causation. A literature search using various search engines and (or) keywords was done. Articles selected for review were chosen following predefined criteria, to extract and analyze data. The results show that the biological and chemical components of inhalable and respirable PM play a significant role in the burden of health effects attributed to PM. These health outcomes include low birth weight, emergency room visit, hospital admission, respiratory and pulmonary diseases, cardiovascular disease, cancer, non-communicable diseases, and premature death, among others. This review justifies the importance of each or synergistic effects of the biological and chemical constituents of PM on health. It also provides information that informs policy on the establishment of exposure limits for PM composition metrics rather than the existing exposure limits of the total mass of PM. This will allow for more effective management strategies for improving outdoor air quality. PMID:27314370

  20. Effects of respirator ambient air cooling on thermophysiological responses and comfort sensations.

    PubMed

    Caretti, David M; Barker, Daniel J

    2014-01-01

    This investigation assessed the thermophysiological and subjective impacts of different respirator ambient air cooling options while wearing chemical and biological personal protective equipment in a warm environment (32.7 ± 0.4°C, 49.6 ± 6.5% RH). Ten volunteers participated in 90-min heat exposure trials with and without respirator (Control) wear and performed computer-generated tasks while seated. Ambient air cooling was provided to respirators modified to blow air to the forehead (FHC) or to the forehead and the breathing zone (BZC) of a full-facepiece air-purifying respirator using a low-flow (45 L·min(-1)) mini-blower. An unmodified respirator (APR) trial was also completed. The highest body temperatures (TTY) and least favorable comfort ratings were observed for the APR condition. With ambient cooling over the last 60 min of heat exposure, TTY averaged 37.4 ± 0.6°C for Control, 38.0 ± 0.4°C for APR, 37.8 ± 0.5°C for FHC, and 37.6 ± 0.7°C for BZC conditions independent of time. Both the FHC and BZC ambient air cooling conditions reduced facial skin temperatures, reduced the rise in body temperatures, and led to more favorable subjective comfort and thermal sensation ratings over time compared to the APR condition; however statistical differences among conditions were inconsistent. Independent of exposure time, average breathing apparatus comfort scores with BZC (7.2 ± 2.5) were significantly different from both Control (8.9 ± 1.4) and APR (6.5 ± 2.2) conditions when ambient cooling was activated. These findings suggest that low-flow ambient air cooling of the face under low work rate conditions and mild hyperthermia may be a practical method to minimize the thermophysiological strain and reduce perceived respirator discomfort.

  1. Evaluation of the user seal check on gross leakage detection of 3 different designs of N95 filtering facepiece respirators.

    PubMed

    Lam, Simon C; Lui, Andrew K F; Lee, Linda Y K; Lee, Joseph K L; Wong, K F; Lee, Cathy N Y

    2016-05-01

    The use of N95 respirators prevents spread of respiratory infectious agents, but leakage hampers its protection. Manufacturers recommend a user seal check to identify on-site gross leakage. However, no empirical evidence is provided. Therefore, this study aims to examine validity of a user seal check on gross leakage detection in commonly used types of N95 respirators. A convenience sample of 638 nursing students was recruited. On the wearing of 3 different designs of N95 respirators, namely 3M-1860s, 3M-1862, and Kimberly-Clark 46827, the standardized user seal check procedure was carried out to identify gross leakage. Repeated testing of leakage was followed by the use of a quantitative fit testing (QNFT) device in performing normal breathing and deep breathing exercises. Sensitivity, specificity, predictive values, and likelihood ratios were calculated accordingly. As indicated by QNFT, prevalence of actual gross leakage was 31.0%-39.2% with the 3M respirators and 65.4%-65.8% with the Kimberly-Clark respirator. Sensitivity and specificity of the user seal check for identifying actual gross leakage were approximately 27.7% and 75.5% for 3M-1860s, 22.1% and 80.5% for 3M-1862, and 26.9% and 80.2% for Kimberly-Clark 46827, respectively. Likelihood ratios were close to 1 (range, 0.89-1.51) for all types of respirators. The results did not support user seal checks in detecting any actual gross leakage in the donning of N95 respirators. However, such a check might alert health care workers that donning a tight-fitting respirator should be performed carefully. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  2. 30 CFR 57.5044 - Respirators.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Respirators. 57.5044 Section 57.5044 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter...

  3. 30 CFR 57.5044 - Respirators.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Respirators. 57.5044 Section 57.5044 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter...

  4. 30 CFR 57.5044 - Respirators.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Respirators. 57.5044 Section 57.5044 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter...

  5. 30 CFR 57.5044 - Respirators.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Respirators. 57.5044 Section 57.5044 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter...

  6. 30 CFR 57.5044 - Respirators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Respirators. 57.5044 Section 57.5044 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter...

  7. Halogenated flame-retardant concentrations in settled dust, respirable and inhalable particulates and polyurethane foam at gymnastic training facilities and residences.

    PubMed

    La Guardia, Mark J; Hale, Robert C

    2015-06-01

    Halogenated flame-retardants (FRs) are used in a wide array of polymer-containing products. Animal studies and structure-activity modeling exercises suggest that FR exposure may result in detrimental toxicological effects. Workers with extended contact with such polymers (e.g., electronic dismantlers, carpet installers and aircraft personnel) have previously been observed to exhibit elevated body burdens of FRs, e.g., polybrominated diphenyl ethers (PBDEs). Recently, elevated PBDE blood levels were also reported in a non-occupational exposure group, gymnasts. These levels were hypothesized to be related to the large volumes of FR-treated polyurethane foam in gymnastics facilities. To further our understanding of workers' potential exposure, we analyzed FR concentrations in indoor dust and size-fractionated air particulates (respirable (<4 μm) and inhalable (>4 μm)) from gymnastic studios. Values were compared to samples from the homes of coaches employed at these facilities. Polyurethane foam blocks (i.e., pit foam) were also analyzed to characterize potential FR sources. FRs examined included those used to flame-retard polyurethane foam: 8 PBDE congeners, two brominated components of Firemaster 550 (2-ethylhexyl 2, 3, 4, 5-tetrabromobenzoate (TBB) and bis(2-ethylhexyl) 3, 4, 5, 6-tetrabromophthalate (TBPH)) and three chlorinated organophosphates (tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP) and tris(1,3-dichloro-2-propyl) phosphate (TDCPP)). Several additional FRs not used in polyurethane were also evaluated. These have also been detected in indoor dust and air and may also lead to adverse health effects. These include: BDE-183 and its replacement product (1, 2-bis(2, 4, 6-tribromophenoxy) ethane (BTBPE), two congeners of the deca-BDE formulation (BDE-206, -209) and their replacement decabromodiphenyl ethane (DBDPE) and hexabromocyclododecane (α-, β-, γ-HBCD), and tetrabromobisphenol-A (TBBPA)). Pit foam contained multiple

  8. Correlation of Respirator Fit Measured on Human Subjects and a Static Advanced Headform

    PubMed Central

    Bergman, Michael S.; He, Xinjian; Joseph, Michael E.; Zhuang, Ziqing; Heimbuch, Brian K.; Shaffer, Ronald E.; Choe, Melanie; Wander, Joseph D.

    2015-01-01

    This study assessed the correlation of N95 filtering face-piece respirator (FFR) fit between a Static Advanced Headform (StAH) and 10 human test subjects. Quantitative fit evaluations were performed on test subjects who made three visits to the laboratory. On each visit, one fit evaluation was performed on eight different FFRs of various model/size variations. Additionally, subject breathing patterns were recorded. Each fit evaluation comprised three two-minute exercises: “Normal Breathing,” “Deep Breathing,” and again “Normal Breathing.” The overall test fit factors (FF) for human tests were recorded. The same respirator samples were later mounted on the StAH and the overall test manikin fit factors (MFF) were assessed utilizing the recorded human breathing patterns. Linear regression was performed on the mean log10-transformed FF and MFF values to assess the relationship between the values obtained from humans and the StAH. This is the first study to report a positive correlation of respirator fit between a headform and test subjects. The linear regression by respirator resulted in R2 = 0.95, indicating a strong linear correlation between FF and MFF. For all respirators the geometric mean (GM) FF values were consistently higher than those of the GM MFF. For 50% of respirators, GM FF and GM MFF values were significantly different between humans and the StAH. For data grouped by subject/respirator combinations, the linear regression resulted in R2 = 0.49. A weaker correlation (R2 = 0.11) was found using only data paired by subject/respirator combination where both the test subject and StAH had passed a real-time leak check before performing the fit evaluation. For six respirators, the difference in passing rates between the StAH and humans was < 20%, while two respirators showed a difference of 29% and 43%. For data by test subject, GM FF and GM MFF values were significantly different for 40% of the subjects. Overall, the advanced headform system has

  9. Method development study for APR cartridge evaluation in fire overhaul exposures.

    PubMed

    Anthony, T Renée; Joggerst, Philip; James, Leonard; Burgess, Jefferey L; Leonard, Stephen S; Shogren, Elizabeth S

    2007-11-01

    In the US, firefighters do not typically wear respiratory protection during overhaul activities, although fitting multi-gas or chemical, biological, radiological and nuclear cartridges to supplied air respirator facepieces has been proposed to reduce exposures. This work developed a method to evaluate the effectiveness of respirator cartridges in smoke that represents overhaul exposures to residential fires. Chamber and penetration concentrations were measured for 91 contaminants, including aldehydes, polynuclear aromatic hydrocarbons, hydrocarbons and methyl isothiocyanate, along with total and respirable particulates. These laboratory tests generated concentrations in the range of field-reported exposures from overhaul activities. With limited tests, no styrene, benzene, acrolein or particulates were detected in air filtered by the respirator cartridge, yet other compounds were detected penetrating the respirator. Because of the complexity of smoke, an exposure index was determined for challenge and filtered air to determine the relative risk of the aggregate exposure to respiratory irritants. The primary contributors to the irritant exposure index in air filtered by the respirator were formaldehyde and acetaldehyde, with total hydrocarbons contributing only 1% to the irritant index. Respirator cartridges were adequate to minimize firefighter exposures to aggregate respiratory irritants if the American Conference of Governmental Industrial Hygienists ceiling limit for formaldehyde is used (0.3 ppm) but not if National Institute for Occupational Safety and Health Recommended Exposure Limit (NIOSH REL) (0.1 ppm) is used, where three of five concentrations in filtered air exceeded the NIOSH REL. Respirator certification allows 1 ppm of formaldehyde to pass through it when challenged at 100 ppm, which may not adequately protect workers to current short-term exposure/ceiling limits. The method developed here recommends specific contaminants to measure in future work

  10. Achieving 'excellent' indoor air quality in commercial offices equipped with air-handling unit--respirable suspended particulate.

    PubMed

    Lam, K S; Chan, F S; Fung, W Y; Lui, B S S; Lau, L W L

    2006-04-01

    A study was carried out to investigate the feasibility of achieving ultra low respirable suspended particulates (RSP) in commercial offices without major modification of existing ventilation systems by enhancing the particulates removal efficiency of existing central ventilation systems. Four types of filters which include pre-filters, cartridge filters, bag filters and high efficiency particulates air (HEPA) filters were tested in a commercial building in Causeway Bay. The results show that an RSP objective of <20 microg/m3 could be met by removing RSP from both the return air and outdoor air supply simultaneously. This level of performance is classed as 'excellent' by the Hong Kong Government, Environmental Protection Department. Filters with efficiency that exceed 80% placed both in the return air and outdoor air were sufficient to meet the objective. It is not necessary to install HEPA filters to achieve the 'excellent' class. The outdoor air filter has great influence on the steady state indoor RSP concentration while the effective cleaning rate is governed by the return air filter. Higher efficiency filters increased the static drop but the volume flow of the air fan was not affected significantly. The additional cost incurred was <5% of the existing operation cost. This paper reports a field study of RSP control for an indoor office environment. The results are directly applicable to building service engineering in the design of ventilation systems using air-handling units. Field observations indicated that indoor RSP in an office environment could be suppressed below 20 microg/m3 within 1 h by the simultaneous filtration of outdoor air and return air. Outdoor air filtration has a great influence on the steady state indoor concentration and return air filtration governs the cleaning rate. It is believed that the results of this study could be extended to the cleaning of other indoor pollutants such as volatile organic compounds.

  11. 40 CFR 721.10581 - Brominated polyurethane prepolymers of methylene diphenyl diisocyanate (MDI) (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., tight-fitting half-face respirator equipped with N100 (if oil aerosols absent), R100, or P100 filters. (B) NIOSH-certified air-purifying, tight-fitting full-face respirator equipped with N100 (if oil...-certified powered air-purifying respirator equipped with a tight-fitting facepiece (either half-face or full...

  12. Respiratory protection from isocyanate exposure in the autobody repair and refinishing industry.

    PubMed

    Liu, Youcheng; Stowe, Meredith H; Bello, Dhimiter; Woskie, Susan R; Sparer, Judy; Gore, Rebecca; Youngs, Fred; Cullen, Mark R; Redlich, Carrie A

    2006-05-01

    This study, part of the Survey of Painters and Repairers of Auto bodies by Yale (SPRAY), evaluated the effectiveness of respiratory protection against exposure to aliphatic polyisocyanates. A total of 36 shops were assessed for respiratory protection program completeness; 142 workers were measured for respirator fit factor (FF) using PortaCount Plus respirator fit tester. Twenty-two painters from 21 shops were sampled using NIOSH method 5525 to determine the workplace protection factor (WPF) of negative pressure, air-purifying half-facepiece respirators equipped with organic vapor cartridges and paint prefilters during spray-painting and priming activities. Only 11 shops (30%) had written respiratory protection programs. Eighty percent of all fit tested workers passed the test on the first try with FF >or= 100, and 92% passed the second test after respirator use training. Overall geometric mean (GM) FF was 1012 for all fit tested workers. Significant differences on pass rate (92% vs. 72%) and on FF (1990 vs. 736) were found between previously fit tested workers vs. nontested workers. Twenty-nine WPF samples were collected. The outside facepiece GM concentration of total isocyanate group (NCO) was 378.4 micro g NCO/m(3) with 96% concentrations exceeding the U.K. short-term exposure limit, 70 micro g NCO/m(3), but no in-facepiece concentrations exceeded the limit. The GM WPF of total NCO was 319 (GSD 4) and the 5th percentile was 54. WPF of total NCO was positively correlated with the duration of painting task. FF positively correlated with WPF when FF was 450. We conclude that negative pressure, air-purifying half-facepiece respirators equipped with organic vapor cartridges and paint prefilters provide effective protection against isocyanate exposure in spray and priming operations if workers are properly trained and fitted.

  13. 42 CFR 84.181 - Non-powered air-purifying particulate filter efficiency level determination.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Non-powered air-purifying particulate filter...-purifying particulate filter efficiency level determination. (a) Twenty filters of each non-powered air-purifying particulate respirator model shall be tested for filter efficiency against: (1) A solid sodium...

  14. 42 CFR 84.181 - Non-powered air-purifying particulate filter efficiency level determination.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Non-powered air-purifying particulate filter...-purifying particulate filter efficiency level determination. (a) Twenty filters of each non-powered air-purifying particulate respirator model shall be tested for filter efficiency against: (1) A solid sodium...

  15. 42 CFR 84.181 - Non-powered air-purifying particulate filter efficiency level determination.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Non-powered air-purifying particulate filter...-purifying particulate filter efficiency level determination. (a) Twenty filters of each non-powered air-purifying particulate respirator model shall be tested for filter efficiency against: (1) A solid sodium...

  16. 42 CFR 84.181 - Non-powered air-purifying particulate filter efficiency level determination.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Non-powered air-purifying particulate filter...-purifying particulate filter efficiency level determination. (a) Twenty filters of each non-powered air-purifying particulate respirator model shall be tested for filter efficiency against: (1) A solid sodium...

  17. 42 CFR 84.181 - Non-powered air-purifying particulate filter efficiency level determination.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Non-powered air-purifying particulate filter...-purifying particulate filter efficiency level determination. (a) Twenty filters of each non-powered air-purifying particulate respirator model shall be tested for filter efficiency against: (1) A solid sodium...

  18. 40 CFR 721.10607 - Aliphatic diisocyanate, homopolymer, alkanol-blocked (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-purifying, tight-fitting half-face respirator equipped with N100 (if oil aerosols absent), R100, or P100 filters. (B) NIOSH-certified air-purifying, tight-fitting full-face respirator equipped with N100 (if oil...-certified powered air-purifying respirator equipped with a tight-fitting facepiece (either half-face or full...

  19. 40 CFR 721.10572 - Benzamide, N-[[4- [(cyclopropylamino)carbonyl] phenyl]sulfonyl]-2-methoxy-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-fitting half-face respirator equipped with N100 (if oil aerosols absent), R100, or P100 filters. (B) NIOSH-certified air-purifying, tight-fitting full-face respirator equipped with N100 (if oil aerosols absent...-purifying respirator equipped with a tight-fitting facepiece (either half-face or full-face) and HEPA...

  20. Organic fuels for respiration in tropical river systems

    NASA Astrophysics Data System (ADS)

    Ward, N.; Keil, R. G.; Richey, J. E.; Krusche, A. V.; Medeiros, P. M.

    2011-12-01

    Watershed-derived organic matter is thought to provide anywhere from 30-90% of the organic matter in rivers (e.g. Hernes et al 2008; Spencer et al 2010). The most abundant biochemicals on land are cellulose, hemicelluloses, and lignin. Combined, they represent as much as 80% of the biomass in a typical forest and as much as 60% of the biomass in a typical field (natural or crop)(Bose et al 2009; Bridgeman et al., 2007; Hu and Zu 2006; Martens et al 2004). They are often assumed to be refractory and hard to degrade, but this assumption is at odds with virtually all observations: soils and marine sediments are not accumulating vast amounts of these compounds (Hedges and Oades, 1997), and degradation experiments suggest that cellulose, hemicelluloses and lignin are reactive and likely to be important fuels for respiration (Benner, 1991; Haddad et al, 1992; Dittmar et al, 2001; Otto and Simpson, 2006). During several trips to the lower Amazon River, incubation experiments were performed in which the biological degradation of lignin phenols was observed in order to assess the contribution of microbial respiration of terrestrially-derived macromolecules to gross respiration and CO2 gas evasion rates. Both particulate and dissolved lignin concentrations decreased by ~40% after being incubated in the dark for 5-7 days, indicating a turnover time of the entire lignin pool of 12-18 days. These results shift the paradigm that lignocellulose derived OM is highly recalcitrant, and indicate that microbial respiration of lignocellulose may play a larger role in total respiration rates/CO2 outgassing than previously thought. A simple mass balance calculation was done to test whether microbial degradation alone could explain the lignin data observed in the field. First, a theoretical particulate lignin concentration for Macapa was calculated based on the observed data at Obidos. The measured rate of particulate lignin degradation was multiplied by the transit time of water from

  1. Respiratory source control using a surgical mask: An in vitro study.

    PubMed

    Patel, Rajeev B; Skaria, Shaji D; Mansour, Mohamed M; Smaldone, Gerald C

    2016-07-01

    Cough etiquette and respiratory hygiene are forms of source control encouraged to prevent the spread of respiratory infection. The use of surgical masks as a means of source control has not been quantified in terms of reducing exposure to others. We designed an in vitro model using various facepieces to assess their contribution to exposure reduction when worn at the infectious source (Source) relative to facepieces worn for primary (Receiver) protection, and the factors that contribute to each. In a chamber with various airflows, radiolabeled aerosols were exhaled via a ventilated soft-face manikin head using tidal breathing and cough (Source). Another manikin, containing a filter, quantified recipient exposure (Receiver). The natural fit surgical mask, fitted (SecureFit) surgical mask and an N95-class filtering facepiece respirator (commonly known as an "N95 respirator") with and without a Vaseline-seal were tested. With cough, source control (mask or respirator on Source) was statistically superior to mask or unsealed respirator protection on the Receiver (Receiver protection) in all environments. To equal source control during coughing, the N95 respirator must be Vaseline-sealed. During tidal breathing, source control was comparable or superior to mask or respirator protection on the Receiver. Source control via surgical masks may be an important adjunct defense against the spread of respiratory infections. The fit of the mask or respirator, in combination with the airflow patterns in a given setting, are significant contributors to source control efficacy. Future clinical trials should include a surgical mask source control arm to assess the contribution of source control in overall protection against airborne infection.

  2. Respiratory source control using a surgical mask: An in vitro study

    PubMed Central

    Patel, Rajeev B.; Skaria, Shaji D.; Mansour, Mohamed M.; Smaldone, Gerald C.

    2016-01-01

    ABSTRACT Cough etiquette and respiratory hygiene are forms of source control encouraged to prevent the spread of respiratory infection. The use of surgical masks as a means of source control has not been quantified in terms of reducing exposure to others. We designed an in vitro model using various facepieces to assess their contribution to exposure reduction when worn at the infectious source (Source) relative to facepieces worn for primary (Receiver) protection, and the factors that contribute to each. In a chamber with various airflows, radiolabeled aerosols were exhaled via a ventilated soft-face manikin head using tidal breathing and cough (Source). Another manikin, containing a filter, quantified recipient exposure (Receiver). The natural fit surgical mask, fitted (SecureFit) surgical mask and an N95-class filtering facepiece respirator (commonly known as an “N95 respirator”) with and without a Vaseline-seal were tested. With cough, source control (mask or respirator on Source) was statistically superior to mask or unsealed respirator protection on the Receiver (Receiver protection) in all environments. To equal source control during coughing, the N95 respirator must be Vaseline-sealed. During tidal breathing, source control was comparable or superior to mask or respirator protection on the Receiver. Source control via surgical masks may be an important adjunct defense against the spread of respiratory infections. The fit of the mask or respirator, in combination with the airflow patterns in a given setting, are significant contributors to source control efficacy. Future clinical trials should include a surgical mask source control arm to assess the contribution of source control in overall protection against airborne infection. PMID:26225807

  3. Inward Leakage Variability between Respirator Fit Test Panels – Part I. Deterministic Approach

    PubMed Central

    Zhuang, Ziqing; Liu, Yuewei; Coffey, Christopher C.; Miller, Colleen; Szalajda, Jonathan

    2015-01-01

    Inter-panel variability has never been investigated. The objective of this study was to determine the variability between different anthropometric panels used to determine the inward leakage (IL) of N95 filtering facepiece respirators (FFRs) and elastomeric half-mask respirators (EHRs). A total of 144 subjects, who were both experienced and non-experienced N95 FFR users, were recruited. Five N95 FFRs and five N95 EHRs were randomly selected from among those models tested previously in our laboratory. The PortaCount Pro+ (without N95-Companion) was used to measure IL of the ambient particles with a detectable size range of 0.02 to 1 μm. The Occupational Safety and Health Administration standard fit test exercises were used for this study. IL test were performed for each subject using each of the 10 respirators. Each respirator/subject combination was tested in duplicate, resulting in a total 20 IL tests for each subject. Three 35-member panels were randomly selected without replacement from the 144 study subjects stratified by the National Institute for Occupational Safety and Health bivariate panel cell for conducting statistical analyses. The geometric mean (GM) IL values for all 10 studied respirators were not significantly different among the three randomly selected 35-member panels. Passing rate was not significantly different among the three panels for all respirators combined or by each model. This was true for all IL pass/fail levels of 1%, 2%, and 5%. Using 26 or more subjects to pass the IL test, all three panels had consistent passing/failing results for pass/fail levels of 1% and 5%. Some disagreement was observed for the 2% pass/fail level. Inter-panel variability exists, but it is small relative to the other sources of variation in fit testing data. The concern about inter-panel variability and other types of variability can be alleviated by properly selecting: pass/fail level (IL 1–5%); panel size (e.g., 25 or 35); and minimum number of subjects

  4. Characterization of airborne and bulk particulate from iron and steel manufacturing facilities.

    PubMed

    Machemer, Steven D

    2004-01-15

    Characterization of airborne and bulk particulate material from iron and steel manufacturing facilities, commonly referred to as kish, indicated graphite flakes and graphite flakes associated with spherical iron oxide particles were unique particle characteristics useful in identifying particle emissions from iron and steel manufacturing. Characterization of airborne particulate material collected in receptor areas was consistent with multiple atmospheric release events of kish particles from the local iron and steel facilities into neighboring residential areas. Kish particles deposited in nearby residential areas included an abundance of graphite flakes, tens of micrometers to millimeters in size, and spherical iron oxide particles, submicrometer to tens of micrometers in size. Bulk kish from local iron and steel facilities contained an abundance of similar particles. Approximately 60% of blast furnace kish by volume consisted of spherical iron oxide particles in the respirable size range. Basic oxygen furnace kish contained percent levels of strongly alkaline components such as calcium hydroxide. In addition, concentrations of respirable Mn in airborne particulate in residential areas and at local iron and steel facilities were approximately 1.6 and 53 times the inhalation reference concentration of 0.05 microg/m3 for chronic inhalation exposure of Mn, respectively. Thus, airborne release of kish may pose potential respirable particulate, corrosive, or toxic hazards for human health and/or a corrosive hazard for property and the environment.

  5. 40 CFR 721.9719 - Tris carbamoyl triazine (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the requirements for § 721.63(a)(4): (A) Air purifying, tight-fitting half-face respirator equipped... filter (N100 if oil aerosols are absent, R100, or P100); (B) Air purifying, tight-fitting full-face...) filter; powered air-purifying respirator equipped with tight-fitting facepiece (either half-face or full...

  6. Numerical studies on the performance of an aerosol respirator with faceseal leakage

    NASA Astrophysics Data System (ADS)

    Zaripov, S. K.; Mukhametzanov, I. T.; Grinshpun, S. A.

    2016-11-01

    We studied the efficiency of a facepiece filtering respirator (FFR) in presence of a measurable faceseal leakage using the previously developed model of a spherical sampler with porous layer. In our earlier study, the model was validated for a specific filter permeability value. In this follow-up study, we investigated the effect of permeability on the overall respirator performance accounting for the faceseal leakage. The Total Inward Leakage (TIL) was calculated as a function of the leakage-to-filter surface ratio and the particle diameter. A good correlation was found between the theoretical and experimental TIL values. The TIL value was shown to increase and the effect of particle size on TIL to decrease as the leakage-to- filter surface ratio grows. The model confirmed that within the most penetrating particle size range (∼50 nm) and at relatively low leakage-to-filter surface ratios, an FFR performs better (TIL is lower) when the filter has a lower permeability which should be anticipated as long as the flow through the filter represents the dominant particle penetration pathway. An increase in leak size causes the TIL to rise; furthermore, under certain leakage-to-filter surface ratios, TIL for ultrafine particles becomes essentially independent on the filter properties due to a greater contribution of the aerosol flow through the faceseal leakage. In contrast to the ultrafine fraction, the larger particles (e.g., 800 nm) entering a typical high- or medium-quality respirator filter are almost fully collected by the filter medium regardless of its permeability; at the same time, the fraction penetrated through the leakage appears to be permeability- dependent: higher permeability generally results in a lower pressure drop through the filter which increases the air flow through the filter at the expense of the leakage flow. The latter reduces the leakage effect thus improving the overall respiratory protection level. The findings of this study provide

  7. Clinician Beliefs and Attitudes Regarding Use of Respiratory Protective Devices and Surgical Masks for Influenza

    PubMed Central

    Pillai, Satish K.; Beekmann, Susan E.; Babcock, Hilary M.; Pavia, Andrew T.; Koonin, Lisa M.; Polgreen, Philip M.

    2015-01-01

    While influenza transmission is thought to occur primarily by droplet spread, the role of airborne spread remains uncertain. Understanding the beliefs and attitudes of infectious disease physicians regarding influenza transmission and respiratory and barrier protection preferences can provide insights into workplace decisions regarding respiratory protection planning. Physicians participating in the Infectious Diseases Society of America’s Emerging Infections Network were queried in November 2013 to determine beliefs and attitudes on influenza transmission. A subset of physicians involved in their facility’s respiratory protection decision making were queried about respirator and surgical mask choices under various pandemic scenarios; availability of, and challenges associated with, respirators in their facility; and protective strategies during disposable N95 shortages. The majority of 686 respondents (98%) believed influenza transmission occurs frequently or occasionally via droplets; 44% of respondents believed transmission occurs via small particles frequently (12%) or occasionally (32%). Among the subset of respondents involved in respiratory protection planning at their facility, over 90% preferred surgical masks during provision of non-aerosol-generating patient care for seasonal influenza. However, for the same type of care during an influenza pandemic, two-thirds of respondents opted for disposable N95 filtering facepiece respirators. In settings where filtering facepiece (disposable) N95 respirators were in short supply, preferred conservation strategies included extended use and reuse of disposable N95s. Use of reusable (elastomeric facepiece) respirator types was viewed less favorably. While respondents identified droplets as the primary mode of influenza transmission, during a high-severity pandemic scenario there was increased support for devices that reduced aerosol-based transmission. Use of potentially less familiar respirator types may

  8. Particle loading time and humidity effects on the efficiency of an N95 filtering facepiece respirator model under constant and inhalation cyclic flows.

    PubMed

    Mahdavi, Alireza; Haghighat, Fariborz; Bahloul, Ali; Brochot, Clothilde; Ostiguy, Claude

    2015-06-01

    It is necessary to investigate the efficiencies of filtering facepiece respirators (FFRs) exposed to ultrafine particles (UFPs) for long periods of time, since the particle loading time may potentially affect the efficiency of FFRs. This article aims to investigate the filtration efficiency for a model of electrostatic N95 FFRs with constant and 'inhalation-only' cyclic flows, in terms of particle loading time effect, using different humidity conditions. Filters were exposed to generated polydisperse NaCl particles. Experiments were performed mimicking an 'inhalation-only' scenario with a cyclic flow of 85 l min(-1) as the minute volume [or 170 l min(-1) as mean inhalation flow (MIF)] and for two constant flows of 85 and 170 l min(-1), under three relative humidity (RH) levels of 10, 50, and 80%. Each test was performed for loading time periods of 6h and the particle penetration (10-205.4nm in electrical mobility diameter) was measured once every 2h. For a 10% RH, the penetration of smaller size particles (<80nm), including the most penetrating particle size (MPPS), decreased over time for both constant and cyclic flows. For 50 and 80% RH levels, the changes in penetration were typically observed in an opposite direction with less magnitude. The penetrations at MPPS increased with respect to loading time under constant flow conditions (85 and 170 l min(-1)): it did not substantially increase under cyclic flows. The comparison of the cyclic flow (85 l min(-1) as minute volume) and constant flow equal to the cyclic flow minute volume indicated that, for all conditions the penetration was significantly less for the constant flow than that of cyclic flow. The comparison between the cyclic (170 l min(-1) as MIF) and constant flow equal to cyclic flow MIF indicated that, for the initial stage of loading, the penetrations were almost equal, but they were different for the final stages of the loading time. For a 10% RH, the penetration of a wide range of sizes was observed

  9. Particulate face masks for protection against airborne pathogens - one size does not fit all: an observational study.

    PubMed

    Winter, Susan; Thomas, Jane H; Stephens, Dianne P; Davis, Joshua S

    2010-03-01

    To determine the proportion of hospital staff who pass fit tests with each of three commonly used particulate face masks, and factors influencing preference and fit test results. Observational study. 50 healthy hospital staff volunteers in an 18-bed general intensive care unit in an Australian teaching hospital. Participants were administered a questionnaire about mask use and their preferred mask and underwent qualitative fit-testing with each of three different particulate masks: Kimberly-Clark Tecnol FluidShield N95 particulate filter respirator (KC), 3M Flat Fold 9320 particulate respirator and 3M 8822 particulate respirator with exhalation valve. Participants who failed fittesting were trained in correct mask donning, and fittesting was repeated. Proportion of participants who passed the fit test for each mask and the effect of training. The proportion of participants who passed a fit test was low for all three masks tested (KC, 16%; flat fold, 28%; and valved, 34%). Rates improved after training: the first mask tested fitted in 18% of participants pre-training and 40% post-training (P = 0.02). None of the masks fitted for 28% of participants. There were no significant predictors of fit-test results. A large proportion of individuals failed a fit test with any given mask, and we were not able to identify any factors that predicted mask fit in individuals. Training on mask use improved the rates of adequate fit. Hospitals should carry a range of P2 masks, and should conduct systematic P2 mask training and fit-testing programs for all staff potentially exposed to airborne pathogens.

  10. Development of an Advanced Respirator Fit-Test Headform

    PubMed Central

    Bergman, Michael S.; Zhuang, Ziqing; Hanson, David; Heimbuch, Brian K.; McDonald, Michael J.; Palmiero, Andrew J.; Shaffer, Ronald E.; Harnish, Delbert; Husband, Michael; Wander, Joseph D.

    2015-01-01

    Improved respirator test headforms are needed to measure the fit of N95 filtering facepiece respirators (FFRs) for protection studies against viable airborne particles. A Static (i.e., non-moving, non-speaking) Advanced Headform (StAH) was developed for evaluating the fit of N95 FFRs. The StAH was developed based on the anthropometric dimensions of a digital headform reported by the National Institute for Occupational Safety and Health (NIOSH) and has a silicone polymer skin with defined local tissue thicknesses. Quantitative fit factor evaluations were performed on seven N95 FFR models of various sizes and designs. Donnings were performed with and without a pre-test leak checking method. For each method, four replicate FFR samples of each of the seven models were tested with two donnings per replicate, resulting in a total of 56 tests per donning method. Each fit factor evaluation was comprised of three 86-sec exercises: “Normal Breathing” (NB, 11.2 liters per min (lpm)), “Deep Breathing” (DB, 20.4 lpm), then NB again. A fit factor for each exercise and an overall test fit factor were obtained. Analysis of variance methods were used to identify statistical differences among fit factors (analyzed as logarithms) for different FFR models, exercises, and testing methods. For each FFR model and for each testing method, the NB and DB fit factor data were not significantly different (P > 0.05). Significant differences were seen in the overall exercise fit factor data for the two donning methods among all FFR models (pooled data) and in the overall exercise fit factor data for the two testing methods within certain models. Utilization of the leak checking method improved the rate of obtaining overall exercise fit factors ≥100. The FFR models, which are expected to achieve overall fit factors ≥ 100 on human subjects, achieved overall exercise fit factors ≥ 100 on the StAH. Further research is needed to evaluate the correlation of FFRs fitted on the StAH to

  11. Effectiveness of dust control methods for crystalline silica and respirable suspended particulate matter exposure during manual concrete surface grinding.

    PubMed

    Akbar-Khanzadeh, Farhang; Milz, Sheryl A; Wagner, Cynthia D; Bisesi, Michael S; Ames, April L; Khuder, Sadik; Susi, Pam; Akbar-Khanzadeh, Mahboubeh

    2010-12-01

    Concrete grinding exposes workers to unacceptable levels of crystalline silica dust, known to cause diseases such as silicosis and possibly lung cancer. This study examined the influence of major factors of exposure and effectiveness of existing dust control methods by simulating field concrete grinding in an enclosed workplace laboratory. Air was monitored during 201 concrete grinding sessions while using a variety of grinders, accessories, and existing dust control methods, including general ventilation (GV), local exhaust ventilation (LEV), and wet grinding. Task-specific geometric mean (GM) of respirable crystalline silica dust concentrations (mg/m³ for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled-grinding, while GV was off/on, were 0.17/0.09, 0.57/0.13, 1.11/0.44, and 23.1/6.80, respectively. Silica dust concentrations (mg/m³ using 100-125 mm (4-5 inch) and 180 mm (7 inch) grinding cups were 0.53/0.22 and 2.43/0.56, respectively. GM concentrations of silica dust were significantly lower for (1) GV on (66.0%) vs. off, and (2) LEV:HEPA- (99.0%), LEV:Shop-vac- (98.1%) or wet- (94.4%) vs. uncontrolled-grinding. Task-specific GM of respirable suspended particulate matter (RSP) concentrations (mg/m³ for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled grinding, while GV was off/on, were 1.58/0.63, 7.20/1.15, 9.52/4.13, and 152/47.8, respectively. GM concentrations of RSP using 100-125 mm and 180 mm grinding cups were 4.78/1.62 and 22.2/5.06, respectively. GM concentrations of RSP were significantly lower for (1) GV on (70.2%) vs. off, and (2) LEV:HEPA- (98.9%), LEV:Shop-vac- (96.9%) or wet- (92.6%) vs. uncontrolled grinding. Silica dust and RSP were not significantly affected by (1) orientation of grinding surfaces (vertical vs. inclined); (2) water flow rates for wet grinding; (3) length of task-specific sampling time; or, (4) among cup sizes of 100, 115 or 125 mm. No combination of factors or control methods reduced an 8-hr exposure level to below the

  12. Recommended test methods and pass/fail criteria for a respirator fit capability test of half-mask air-purifying respirators

    PubMed Central

    Zhuang, Ziqing; Bergman, Michael; Lei, Zhipeng; Niezgoda, George; Shaffer, Ronald

    2017-01-01

    This study assessed key test parameters and pass/fail criteria options for developing a respirator fit capability (RFC) test for half-mask air-purifying particulate respirators. Using a 25-subject test panel, benchmark RFC data were collected for 101 National Institute for Occupational Safety and Health-certified respirator models. These models were further grouped into 61 one-, two-, or three-size families. Fit testing was done using a PortaCount® Plus with N95-Companion accessory and an Occupational Safety and Health Administration-accepted quantitative fit test protocol. Three repeated tests (donnings) per subject/respirator model combination were performed. The panel passing rate (PPR) (number or percentage of the 25-subject panel achieving acceptable fit) was determined for each model using five different alternative criteria for determining acceptable fit. When the 101 models are evaluated individually (i.e., not grouped by families), the percentages of models capable of fitting >75% (19/25 subjects) of the panel were 29% and 32% for subjects achieving a fit factor ≥100 for at least one of the first two donnings and at least one of three donnings, respectively. When the models are evaluated grouped into families and using >75% of panel subjects achieving a fit factor ≥100 for at least one of two donnings as the PPR pass/fail criterion, 48% of all models can pass. When >50% (13/25 subjects) of panel subjects was the PPR criterion, the percentage of passing models increased to 70%. Testing respirators grouped into families and evaluating the first two donnings for each of two respirator sizes provided the best balance between meeting end user expectations and creating a performance bar for manufacturers. Specifying the test criterion for a subject obtaining acceptable fit as achieving a fit factor ≥100 on at least one out of the two donnings is reasonable because a majority of existing respirator families can achieve an PPR of >50% using this criterion

  13. Recommended test methods and pass/fail criteria for a respirator fit capability test of half-mask air-purifying respirators.

    PubMed

    Zhuang, Ziqing; Bergman, Michael; Lei, Zhipeng; Niezgoda, George; Shaffer, Ronald

    2017-06-01

    This study assessed key test parameters and pass/fail criteria options for developing a respirator fit capability (RFC) test for half-mask air-purifying particulate respirators. Using a 25-subject test panel, benchmark RFC data were collected for 101 National Institute for Occupational Safety and Health-certified respirator models. These models were further grouped into 61 one-, two-, or three-size families. Fit testing was done using a PortaCount® Plus with N95-Companion accessory and an Occupational Safety and Health Administration-accepted quantitative fit test protocol. Three repeated tests (donnings) per subject/respirator model combination were performed. The panel passing rate (PPR) (number or percentage of the 25-subject panel achieving acceptable fit) was determined for each model using five different alternative criteria for determining acceptable fit. When the 101 models are evaluated individually (i.e., not grouped by families), the percentages of models capable of fitting >75% (19/25 subjects) of the panel were 29% and 32% for subjects achieving a fit factor ≥100 for at least one of the first two donnings and at least one of three donnings, respectively. When the models are evaluated grouped into families and using >75% of panel subjects achieving a fit factor ≥100 for at least one of two donnings as the PPR pass/fail criterion, 48% of all models can pass. When >50% (13/25 subjects) of panel subjects was the PPR criterion, the percentage of passing models increased to 70%. Testing respirators grouped into families and evaluating the first two donnings for each of two respirator sizes provided the best balance between meeting end user expectations and creating a performance bar for manufacturers. Specifying the test criterion for a subject obtaining acceptable fit as achieving a fit factor ≥100 on at least one out of the two donnings is reasonable because a majority of existing respirator families can achieve an PPR of >50% using this criterion

  14. Natural organic matter as electron acceptor: experimental evidence for its important role in anaerobic respiration

    NASA Astrophysics Data System (ADS)

    Lau, Maximilian Peter; Sander, Michael; Gelbrecht, Jörg; Hupfer, Michael

    2014-05-01

    Microbial respiration is a key driver of element cycling in oxic and anoxic environments. Upon depletion of oxygen as terminal electron acceptor (TEA), a number of anaerobic bacteria can employ alternative TEA for intracellular energy generation. Redox active quinone moieties in dissolved organic matter (DOM) are well known electron acceptors for microbial respiration. However, it remains unclear whether quinones in adsorbed and particulate OM accept electrons in a same way. In our studies we aim to understand the importance of natural organic matter (NOM) as electron acceptors for microbial energy gain and its possible implications for methanogenesis. Using a novel electrochemical approach, mediated electrochemical reduction and -oxidation, we can directly quantify reduced hydroquinone and oxidized quionone moieties in dissolved and particulate NOM samples. In a mesocosm experiment, we rewetted sediment and peat soil and followed electron transfer to the inorganic and organic electron acceptors over time. We found that inorganic and organic electron acceptor pools were depleted over the same timescales. More importantly, we showed that organic, NOM-associated electron accepting moieties represent as much as 21 40% of total TEA inventories. These findings support earlier studies that propose that the reduction of quinone moieties in particulate organic matter competitively suppresses methanogenesis in wetland soils. Our results indicate that electron transfer to organic, particulate TEA in inundated ecosystems has to be accounted for when establishing carbon budgets in and projecting greenhouse gas emissions from these systems.

  15. SYSTEMIC TRANSLOCATION OF PARTICULATE MATTER-ASSOCIATED METALS FOLLOWING A SINGLE INTRATRACHEAL INSTILLATION IN RATS

    EPA Science Inventory

    Respirable ambient particulate matter (PM) exposure has been associated with an increased risk of cardiovascular disease. Direct translocation of PM associated metals from the lungs into systemic circulation may be partly responsible. We measured elemental content of lungs, pla...

  16. 42 CFR 84.170 - Non-powered air-purifying particulate respirators; description.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... inhalation pressure to draw the ambient air through the air-purifying filter elements (filters) to remove... classified into three series, N-, R-, and P-series. The N-series filters are restricted to use in those workplaces free of oil aerosols. The R- and P-series filters are intended for removal of any particulate that...

  17. 42 CFR 84.170 - Non-powered air-purifying particulate respirators; description.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... inhalation pressure to draw the ambient air through the air-purifying filter elements (filters) to remove... classified into three series, N-, R-, and P-series. The N-series filters are restricted to use in those workplaces free of oil aerosols. The R- and P-series filters are intended for removal of any particulate that...

  18. 42 CFR 84.170 - Non-powered air-purifying particulate respirators; description.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... inhalation pressure to draw the ambient air through the air-purifying filter elements (filters) to remove... classified into three series, N-, R-, and P-series. The N-series filters are restricted to use in those workplaces free of oil aerosols. The R- and P-series filters are intended for removal of any particulate that...

  19. 42 CFR 84.170 - Non-powered air-purifying particulate respirators; description.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... inhalation pressure to draw the ambient air through the air-purifying filter elements (filters) to remove... classified into three series, N-, R-, and P-series. The N-series filters are restricted to use in those workplaces free of oil aerosols. The R- and P-series filters are intended for removal of any particulate that...

  20. 42 CFR 84.170 - Non-powered air-purifying particulate respirators; description.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... inhalation pressure to draw the ambient air through the air-purifying filter elements (filters) to remove... classified into three series, N-, R-, and P-series. The N-series filters are restricted to use in those workplaces free of oil aerosols. The R- and P-series filters are intended for removal of any particulate that...

  1. Impact of Mining Waste on Airborne Respirable Particulates in Northeastern Oklahoma, United States

    EPA Science Inventory

    Atmospheric dispersion of particles from mine waste is potentially an important route of human exposure to metals in communities close to active and abandoned mining areas. In this study, we assessed sources of mass and metal concentrations in two size fractions of respirable pa...

  2. High diversity of fungi in air particulate matter.

    PubMed

    Fröhlich-Nowoisky, Janine; Pickersgill, Daniel A; Després, Viviane R; Pöschl, Ulrich

    2009-08-04

    Fungal spores can account for large proportions of air particulate matter, and they may potentially influence the hydrological cycle and climate as nuclei for water droplets and ice crystals in clouds, fog, and precipitation. Moreover, some fungi are major pathogens and allergens. The diversity of airborne fungi is, however, not well-known. By DNA analysis we found pronounced differences in the relative abundance and seasonal cycles of various groups of fungi in coarse and fine particulate matter, with more plant pathogens in the coarse fraction and more human pathogens and allergens in the respirable fine particle fraction (<3 microm). Moreover, the ratio of Basidiomycota to Ascomycota was found to be much higher than previously assumed, which might also apply to the biosphere.

  3. Comparative inflammatory effects of differential particulate matter species in an OVA-sensitization and challenge model

    EPA Science Inventory

    Exposure to respirable ambient particulate matter (APM) provokes allergic immunity that may also occur on exposure to environmental diesel exhaust particles (eDEP) or emission source DEP (cDEP). Our hypothesis tested whether APM, eDEP or cDEP provide immune adjuvancy in an antige...

  4. Association of expired nitric oxide with occupational particulate exposure.

    PubMed Central

    Kim, Jee Young; Wand, Matthew P; Hauser, Russ; Mukherjee, Sutapa; Herrick, Robert F; Christiani, David C

    2003-01-01

    Particulate air pollution has been associated with adverse respiratory health effects. This study assessed the utility of expired nitric oxide to detect acute airway responses to metal-containing fine particulates. Using a repeated-measures study design, we investigated the association between the fractional concentration of expired nitric oxide (F(E)NO) and exposure to particulate matter with an aerodynamic mass median diameter of less than or equal to 2.5 micro m (PM(2.5)) in boilermakers exposed to residual oil fly ash and metal fumes. Subjects were monitored for 5 days during boiler repair overhauls in 1999 (n = 20) or 2000 (n = 14). The Wilcoxon median baseline F(E)NO was 10.6 ppb [95% confidence interval (CI): 9.1, 12.7] in 1999 and 7.4 ppb (95% CI: 6.7, 8.0) in 2000. The Wilcoxon median PM(2.5) 8-hr time-weighted average was 0.56 mg/m(3) (95% CI: 0.37, 0.93) in 1999 and 0.86 mg/m(3) (95% CI: 0.65, 1.07) in 2000. F(E)NO levels during the work week were significantly lower than baseline F(E)NO in 1999 (p < 0.001). A significant inverse exposure-response relationship between log-transformed F(E)NO and the previous workday's PM(2.5) concentration was found in 1999, after adjusting for smoking status, age, and sampling year. With each 1 mg/m(3) incremental increase in PM(2.5) exposure, log F(E)NO decreased by 0.24 (95% CI: -0.38, -0.10) in 1999. The lack of an exposure-response relationship between PM(2.5) exposure and F(E)NO in 2000 could be attributable to exposure misclassification resulting from the use of respirators. In conclusion, occupational exposure to metal-containing fine particulates was associated with significant decreases in F(E)NO in a survey of workers with limited respirator usage. PMID:12727593

  5. Respirable Uranyl-Vanadate Containing Particulate Matter Derived from a Legacy Uranium Mine Site Exhibits Potentiated Cardiopulmonary Toxicity.

    PubMed

    Zychowski, Katherine E; Kodali, Vamsi; Harmon, Molly; Tyler, Christina; Sanchez, Bethany; Ordonez Suarez, Yoselin; Herbert, Guy; Wheeler, Abigail; Avasarala, Sumant; Cerrato, José M; Kunda, Nitesh K; Muttil, Pavan; Shuey, Chris; Brearley, Adrian; Ali, Abdul-Mehdi; Lin, Yan; Shoeb, Mohammad; Erdely, Aaron; Campen, Matthew J

    2018-04-05

    Exposure to windblown particulate matter (PM) arising from legacy uranium (U) mine sites in the Navajo Nation may pose a human health hazard due to their potentially high metal content, including U and vanadium (V). To assess the toxic impact of PM derived from Claim 28 (a priority U mine) compared to background PM, and consider the putative role of metal species U and V. Two representative sediment samples from Navajo Nation sites (Background PM and Claim 28 PM) were obtained, characterized in terms of chemistry and morphology, and fractioned to the respirable (≤10μm) fraction. Mice were dosed with either PM sample, uranyl acetate or vanadyl sulfate via aspiration (100µg), with assessments of pulmonary and vascular toxicity 24h later. PM samples were also examined for in vitro effects on cytotoxicity, oxidative stress, phagocytosis, and inflammasome induction. Claim 28 PM10 was highly enriched with U and V and exhibited a unique nanoparticle ultrastructure compared to background PM10. Claim 28 PM10 exhibited enhanced pulmonary and vascular toxicity relative to background PM10. Both U and V exhibited complementary pulmonary inflammatory potential, with U driving a classical inflammatory cytokine profile (elevated IL-1β, TNFα, KC/GRO) while V preferentially induced a different cytokine pattern (elevated IL-5, IL-6, IL-10). Claim 28 PM10 was more potent than background PM10 in terms of in vitro cytotoxicity, impairment of phagocytosis, and oxidative stress responses. Resuspended PM10 derived from U mine waste exhibit greater cardiopulmonary toxicity than background dusts. Rigorous exposure assessment is needed to gauge the regional health risks imparted by these unremediated sites.

  6. THE ASSOCIATION OF EXPOSURE TO PARTICULATE MATTER AND RELATED AIR POLLUTANTS WITH SPECIFIC HEALTH EFFECTS IN HEALTHY HIGHWAY PATROL OFFICERS

    EPA Science Inventory

    Estimated exposures to ambient respirable particulate matter (PM) and related co-pollutants have been statistically associated with mortality and morbidity in epidemiological studies conducted throughout the world. Although some subpopulations (e.g., asthmatics; elderly, pulmonar...

  7. The Respiratory Protection Effectiveness Clinical Trial (ResPECT): a cluster-randomized comparison of respirator and medical mask effectiveness against respiratory infections in healthcare personnel.

    PubMed

    Radonovich, Lewis J; Bessesen, Mary T; Cummings, Derek A; Eagan, Aaron; Gaydos, Charlotte; Gibert, Cynthia; Gorse, Geoffrey J; Nyquist, Ann-Christine; Reich, Nicholas G; Rodrigues-Barradas, Maria; Savor-Price, Connie; Shaffer, Ronald E; Simberkoff, Michael S; Perl, Trish M

    2016-06-02

    Although N95 filtering facepiece respirators and medical masks are commonly used for protection against respiratory infections in healthcare settings, more clinical evidence is needed to understand the optimal settings and exposure circumstances for healthcare personnel to use these devices. A lack of clinically germane research has led to equivocal, and occasionally conflicting, healthcare respiratory protection recommendations from public health organizations, professional societies, and experts. The Respiratory Protection Effectiveness Clinical Trial (ResPECT) is a prospective comparison of respiratory protective equipment to be conducted at multiple U.S. study sites. Healthcare personnel who work in outpatient settings will be cluster-randomized to wear N95 respirators or medical masks for protection against infections during respiratory virus season. Outcome measures will include laboratory-confirmed viral respiratory infections, acute respiratory illness, and influenza-like illness. Participant exposures to patients, coworkers, and others with symptoms and signs of respiratory infection, both within and beyond the workplace, will be recorded in daily diaries. Adherence to study protocols will be monitored by the study team. ResPECT is designed to better understand the extent to which N95s and MMs reduce clinical illness among healthcare personnel. A fully successful study would produce clinically relevant results that help clinician-leaders make reasoned decisions about protection of healthcare personnel against occupationally acquired respiratory infections and prevention of spread within healthcare systems. The trial is registered at clinicaltrials.gov, number NCT01249625 (11/29/2010).

  8. Determination of exposure to respirable quartz in the stone crushing units at Azendarian-West of Iran.

    PubMed

    Bahrami, Abdul Rahman; Golbabai, Faridah; Mahjub, Hossien; Qorbani, Farshid; Aliabadi, Mohsan; Barqi, Mohamadali

    2008-08-01

    The purpose of this study is to describe the personal exposure to respirable dust and quartz and in stone crushing units located at west of Iran. A size of 40 personal samples and 40 stationary samples were obtained and analysis was done by X-ray diffraction (XRD). The results of personal sampling were shown the concentrations of respirable dust exposure level in workers of process, hopper and drivers were 1.90, 2.22, 1.41 times greater than Occupational Safety and Health Administration permissible exposure limit (OSHA PEL). The average value of total dust and respirable dust emission from stationary sources was 9.46 mg/m(3), 1.24 mg/m(3) respectively, showing that 13.8 % of total dust is respirable. The efficiency of local exhaust ventilation (LEV) to control of particles inside of industrial units was greater than 99%. It is concluded from this research the particulate generated from stone crushing activities contain a significant amount of respirable particle. The amount of free silica in stone quartz is 85 to 97 percent that emission of particles effect to health workers. LEV has important effect in the removal of silica particles in stone crushing units. The worker of hoppers still exposed to silica more than standard limits.

  9. Health and respirable particulate (PM10) air pollution: a causal or statistical association?

    PubMed Central

    Gamble, J F; Lewis, R J

    1996-01-01

    Numerous studies have reported weak but statistically significant acute health effects of particulate air pollution. The associations are observed at levels below the current U.S. standard of 150 micrograms/m3 (24 hr). Health effects include acute increased mortality from cardiopulmonary conditions and acute morbidity such as hospital admissions for related diseases. We reviewed recent epidemiology studies to evaluate whether criteria for causality are met, and we conclude that they are not. The weak associations are as likely to be due to confounding by weather, copollutants, or exposure misclassification as by ambient particulate matter (PM). The results from the same metropolitan areas are inconsistent, and PM explains such a small amount of the variability in mortality/morbidity that the association has little practical significance. Finally, experimental chamber studies of susceptible individuals exposed to PM concentrations well above 150 micrograms/m3 provide no evidence to support the morbidity/mortality findings. None of the criteria for establishing causality of the PM/mortality hypothesis are clearly met at ambient concentrations common in many U.S. cities. Images p838-a Figure 1. PMID:8875158

  10. Respirable dust and respirable silica exposure in Ontario gold mines.

    PubMed

    Verma, Dave K; Rajhans, Gyan S; Malik, Om P; des Tombe, Karen

    2014-01-01

    A comprehensive survey of respirable dust and respirable silica in Ontario gold mines was conducted by the Ontario Ministry of Labor during 1978-1979. The aim was to assess the feasibility of introducing gravimetric sampling to replace the assessment method which used konimeters, a device which gave results in terms of number of particles per cubic centimeter (ppcc) of air. The study involved both laboratory and field assessments. The field assessment involved measurement of airborne respirable dust and respirable silica at all eight operating gold mines of the time. This article describes the details of the field assessment. A total of 288 long-term (7-8 hr) personal respirable dust air samples were collected from seven occupational categories in eight gold mines. The respirable silica (α-quartz) was determined by x-ray diffraction method. The results show that during 1978-1979, the industry wide mean respirable dust was about 1 mg/m(3), and the mean respirable silica was 0.08 mg/m(3.)The mean% silica in respirable dust was 7.5%. The data set would be useful in future epidemiological and health studies, as well as in assessment of workers' compensation claims for occupational diseases such as silicosis, chronic obstructive pulmonary disease (COPD), and autoimmune diseases such as renal disease and rheumatoid arthritis.

  11. Real-time non-invasive detection of inhalable particulates delivered into live mouse airways.

    PubMed

    Donnelley, Martin; Morgan, Kaye S; Fouras, Andreas; Skinner, William; Uesugi, Kentaro; Yagi, Naoto; Siu, Karen K W; Parsons, David W

    2009-07-01

    Fine non-biological particles small enough to be suspended in the air are continually inhaled as we breathe. These particles deposit on airway surfaces where they are either cleared by airway defences or can remain and affect lung health. Pollutant particles from vehicles, building processes and mineral and industrial dusts have the potential to cause both immediate and delayed health problems. Because of their small size, it has not been possible to non-invasively examine how individual particles deposit on live airways, or to consider how they behave on the airway surface after deposition. In this study, synchrotron phase-contrast X-ray imaging (PCXI) has been utilized to detect and monitor individual particle deposition. The in vitro detectability of a range of potentially respirable particulates was first determined. Of the particulates tested, only asbestos, quarry dust, fibreglass and galena (lead sulfate) were visible in vitro. These particulates were then examined after delivery into the nasal airway of live anaesthetized mice; all were detectable in vivo but each exhibited different surface appearances and behaviour along the airway surface. The two fibrous particulates appeared as agglomerations enveloped by fluid, while the non-fibrous particulates were present as individual particles. Synchrotron PCXI provides the unique ability to non-invasively detect and track deposition of individual particulates in live mouse airways. With further refinement of particulate sizing and delivery techniques, PCXI should provide a novel approach for live animal monitoring of airway particulates relevant to lung health.

  12. A comparison of total inward leakage measured using sodium chloride (NaCl) and corn oil aerosol methods for air-purifying respirators.

    PubMed

    Rengasamy, Samy; Zhuang, Ziqing; Niezgoda, George; Walbert, Gary; Lawrence, Robert; Boutin, Brenda; Hudnall, Judith; Monaghan, William P; Bergman, Michael; Miller, Colleen; Harris, James; Coffey, Christopher

    2018-05-21

    The International Organization for Standardization (ISO) standard 16900-1:2014 specifies the use of sodium chloride (NaCl) and corn oil aerosols, and sulfur hexafluoride gas for measuring total inward leakage (TIL). However, a comparison of TIL between different agents is lacking. The objective of this study was to measure and compare TIL for respirators using corn oil and NaCl aerosols. TIL was measured with 10 subjects donning two models of filtering facepiece respirators (FFRs) including FFP1, N95, P100, and elastomeric half-mask respirators (ERs) in NaCl and corn oil aerosol test chambers, using continuous sampling methods. After fit testing with a PortaCount (TSI, St. Paul, MN) using the Occupational Safety and Health Administration (OSHA) protocol, five subjects were tested in the NaCl chamber first and then in the corn oil chamber, while other subjects tested in the reverse order. TIL was measured as a ratio of mass-based aerosol concentrations in-mask to the test chamber, while the subjects performed ISO 16900-1-defined exercises. The concentration of NaCl aerosol was measured using two flame photometers, and corn oil aerosol was measured with one light scattering photometer. The same instruments were used to measure filter penetration in both chambers using a Plexiglas® setup. The size distribution of aerosols was determined using a scanning mobility particle sizer and charge was measured with an electrometer. Filter efficiency was measured using an 8130 Automated Filter Tester (TSI). Results showed the geometric mean TIL for corn oil aerosol for one model each of all respirator categories, except P100, were significantly (p<0.05) greater than for NaCl aerosol. Filter penetration in the two test chambers showed a trend similar to TIL. The count median diameter was ∼82 nm for NaCl and ∼200 nm for corn oil aerosols. The net positive charge for NaCl aerosol was relatively larger. Both fit factor and filter efficiency influence TIL measurement. Overall

  13. PM 2.5 Airborne Particulates Near Frac Sand Operations.

    PubMed

    Walters, Kristin; Jacobson, Jeron; Kroening, Zachary; Pierce, Crispin

    2015-11-01

    The rapid growth of hydraulic fracturing for oil and gas extraction in the U.S. has led to 135 active "frac" sand mines, processing plants, and rail transfer stations in Wisconsin. Potential environmental health risks include increased truck traffic, noise, ecosystem loss, and groundwater, light, and air pollution. Emitted air contaminants include fine particulate matter (PM2.5) and respirable crystalline silica. Inhalation of fine dust particles causes increased mortality, cardiovascular disease, lung disease, and lung cancer. In the authors' pilot study, use of a filter-based ambient particulate monitor found PM2.5 levels of 5.82-50.8 µg/m3 in six 24-hour samples around frac sand mines and processing sites. Enforcement of the existing U.S. Environmental Protection Agency annual PM2.5 standard of 12 µg/m3 is likely to protect the public from silica exposure risks as well. PM2.5 monitoring around frac sand sites is needed to ensure regulatory compliance, inform nearby communities, and protect public health.

  14. Size and chemical characterization of airborne particulate matter in Spokane

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Haller, L.; Claiborn, C.; Westberg, H.

    1996-12-31

    Recent health effects studies suggest that the present air quality standard for aerosols, which is based upon respirable particles, does not adequately protect public health; Thus the standard is currently under review. In July, 1994, a comprehensive study was initiated in Spokane to study the relationship between various size fractions and chemical components of atmospheric aerosol and health effects. This study is one of the most comprehensive particulate matter studies conducted to date, and is one of a limited number of studies that have been conducted in the and west, where presumably a significant portion of the aerosol will bemore » derived from geological materials. Continuous fine and coarse particulate matter measurements are made at two location (one is in industrial area, and the other in residential area). At the residential site, particulate matter smaller than 1.0 {mu}m, and ultra fine particles are also continuously monitored, and analyzed for a variety of chemical species including elemental components, ionic species, soluble iron, elemental and organic carbon and acidity. Preliminary results indicate that the windblown dust enhances both the fine and coarse fractions of particulate matter in Spokane. Seasonal trends in chemical composition and size characterization will be examined. The relationships between the 24-hour average values and peak hourly values, as well as differences between weekday and weekend levels, will also be discussed.« less

  15. Effects of MERV 16 filters and routine work practices on enclosed cabs for reducing respirable dust and DPM exposures in an underground limestone mine

    PubMed Central

    Noll, J.D.; Cecala, A.B.; J.A.Organiscak; Rider, J.P.

    2015-01-01

    An effective technique to minimize miners’ respirable dust and diesel exposure on mobile mining equipment is to place mine operators in enclosed cabs with designed filtration and pressurization systems. Many factors affect the performance of these enclosed cab systems, and one of the most significant factors is the effectiveness of the filtration system. High-efficiency particulate air (HEPA)-type filters are typically used because they are highly efficient at capturing all types and sizes of particles, including those in the submicron range such as diesel particulate matter (DPM). However, in laboratory tests, minimum efficiency reporting value (MERV) 16 filters have proven to be highly efficient for capturing DPM and respirable dust. Also, MERV 16 filters can be less restrictive to cab airflow and less expensive than HEPA filters. To verify their effectiveness in the field, MERV 16 filters were used in the enclosed cab filtration system on a face drill and roof bolting mining machine and tested at an underground limestone mine. Test results showed that DPM and respirable dust concentrations were reduced by more than 90% when the cabs were properly sealed. However, when the cab door was opened periodically throughout the shift, the reduction efficiency of the MERV 16 filters was reduced to 80% on average. PMID:26236044

  16. Fogging formulations for fixation of particulate contamination in ductwork and enclosures

    DOEpatents

    Maresca, Jr., Joseph W.; Kostelnik, Lori M.; Kriskivich, James R.; Demmer, Rick L.; Tripp, Julia L.

    2015-09-08

    A method and an apparatus using aqueous fixatives for fogging of ventilation ductwork, enclosures, or buildings containing dust, lint, and particulates that may be contaminated by radionuclides and other dangerous or unsafe particulate contaminants, which method and apparatus are capable of (1) obtaining full coverage within the ductwork and (2) penetrating and fixing the lint, dust and large particles present in the ductwork so that no airborne particles are released during or after the application of the fixative. New aqueous fogging solutions outperform conventional glycerin-based solutions. These aqueous solutions will fog using conventional methods of application and contain a surfactant to aid wetting and penetration of the lint and dust, a binder to stabilize loose or respirable particles, and an agent to aid in fogging and enhance adhesiveness. The solutions are safe and easy to use.

  17. Ultrafine and respirable particle exposure during vehicle fire suppression.

    PubMed

    Evans, Douglas E; Fent, Kenneth W

    2015-10-01

    Vehicle fires are a common occurrence, yet few studies have reported exposures associated with burning vehicles. This article presents an assessment of firefighters' potential for ultrafine and respirable particle exposure during vehicle fire suppression training. Fires were initiated within the engine compartment and passenger cabins of three salvaged vehicles, with subsequent water suppression by fire crews. Firefighter exposures were monitored with an array of direct reading particle and air quality instruments. A flexible metallic duct and blower drew contaminants to the instrument array, positioned at a safe distance from the burning vehicles, with the duct inlet positioned at the nozzle operator's shoulder. The instruments measured the particle number, active surface area, respirable particle mass, photoelectric response, aerodynamic particle size distributions, and air quality parameters. Although vehicle fires were suppressed quickly (<10 minutes), firefighters may be exposed to short duration, high particle concentration episodes during fire suppression, which are orders of magnitude greater than the ambient background concentration. A maximum transient particle concentration of 1.21 × 10(7) particles per cm(3), 170 mg m(-3) respirable particle mass, 4700 μm(2) cm(-3) active surface area and 1400 (arbitrary units) in photoelectric response were attained throughout the series of six fires. Expressed as fifteen minute time-weighted averages, engine compartment fires averaged 5.4 × 10(4) particles per cm(3), 0.36 mg m(-3) respirable particle mass, 92 μm(2) cm(-3) active particle surface area and 29 (arbitrary units) in photoelectric response. Similarly, passenger cabin fires averaged 2.04 × 10(5) particles per cm(3), 2.7 mg m(-3) respirable particle mass, 320 μm(2) cm(-3) active particle surface area, and 34 (arbitrary units) in photoelectric response. Passenger cabin fires were a greater potential source of exposure than engine compartment fires. The

  18. Ultrafine and respirable particle exposure during vehicle fire suppression

    PubMed Central

    Fent, Kenneth W.

    2015-01-01

    Vehicle fires are a common occurrence, yet few studies have reported exposures associated with burning vehicles. This article presents an assessment of firefighters’ potential for ultrafine and respirable particle exposure during vehicle fire suppression training. Fires were initiated within the engine compartment and passenger cabins of three salvaged vehicles, with subsequent water suppression by fire crews. Firefighter exposures were monitored with an array of direct reading particle and air quality instruments. A flexible metallic duct and blower drew contaminants to the instrument array, positioned at a safe distance from the burning vehicles, with the duct inlet positioned at the nozzle operator’s shoulder. The instruments measured the particle number, active surface area, respirable particle mass, photoelectric response, aerodynamic particle size distributions, and air quality parameters. Although vehicle fires were suppressed quickly (<10 minutes), firefighters may be exposed to short duration, high particle concentration episodes during fire suppression, which are orders of magnitude greater than the ambient background concentration. A maximum transient particle concentration of 1.21 × 107 particles per cm3, 170 mg m−3 respirable particle mass, 4700 μm2 cm−3 active surface area and 1400 (arbitrary units) in photoelectric response were attained throughout the series of six fires. Expressed as fifteen minute time-weighted averages, engine compartment fires averaged 5.4 × 104 particles per cm3, 0.36 mg m−3 respirable particle mass, 92 μm2 cm−3 active particle surface area and 29 (arbitrary units) in photoelectric response. Similarly, passenger cabin fires averaged 2.04 × 105 particles per cm3, 2.7 mg m−3 respirable particle mass, 320 μm2 cm−3 active particle surface area, and 34 (arbitrary units) in photoelectric response. Passenger cabin fires were a greater potential source of exposure than engine compartment fires. The wind direction

  19. Characterization of Carbon Particulates in the Exit Flow of a Plasma Pyrolysis Assembly (PPA) Reactor

    NASA Technical Reports Server (NTRS)

    Green, Robert D.; Meyer, Marit E.; Agui, Juan H.; Berger, Gordon M.; Vijayakumar, R.; Abney, Morgan B.; Greenwood, Zachary

    2015-01-01

    The ISS presently recovers oxygen from crew respiration via a Carbon Dioxide Reduction Assembly (CRA) that utilizes the Sabatier chemical process to reduce captured carbon dioxide to methane (CH4) and water. In order to recover more of the hydrogen from the methane and increase oxygen recovery, NASA Marshall Space Flight Center (MSFC) is investigating a technology, plasma pyrolysis, to convert the methane to acetylene. The Plasma Pyrolysis Assembly (or PPA), achieves 90% or greater conversion efficiency, but a small amount of solid carbon particulates are generated as a side product and must be filtered before the acetylene is removed and the hydrogen-rich gas stream is recycled back to the CRA. In this work, we present the experimental results of an initial characterization of the carbon particulates in the PPA exit gas stream. We also present several potential options to remove these carbon particulates via carbon traps and filters to minimize resupply mass and required downtime for regeneration.

  20. Development of emission factors for particulate matter in a school

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Scheff, P.A.; Paulius, V.; Conroy, L.M.

    1999-07-01

    Schools have complex indoor environments which are influenced by many factors such as number of occupants, building design, office equipment, cleaning agents, and school activities. Like large office buildings, school environments may be adversely influenced by deficiencies in ventilation which may be due to improper operation of HVAC systems, attempts at energy efficiency that limit the supply of outdoor air, or remodeling of building components. Most importantly, children spend up to a third of their time in these structures, and thus it is desirable to better understand the environmental quality in these buildings. A middle school (grades 6 to 8)more » in a residential section of Springfield, IL was selected for this baseline indoor air quality survey. The school was characterized as having no health complaints, good maintenance schedules, and did not contain carpeting within the classrooms or hallways. The focus of this paper is on the measurements of air quality in the school. The development of emission factors for particulate matter is also discussed. Four indoor locations including the Cafeteria, a Science Classroom, an Art Classroom, and the Lobby outside of the main office, and one outdoor location were sampled for various environmental comfort and pollutant parameters for one week in February of 1997. Integrated samples (8 hour sampling time) for respirable and total particulate matter, and short-term measurements of bioaerosols (two minute samples, three times per day) on three consecutive days were collected at each of the indoor and outdoor sites. Continuous measurements of carbon dioxide, carbon monoxide, temperature and humidity were logged at all locations for five days. Continuous measurements of respirable particulate matter were also collected in the Lobby area. Detailed logs of occupant activity were also collected at each indoor monitoring location throughout the study. Total particle concentrations ranged from 29 to 177 {micro}g/m{sup 3} in

  1. Simulation and evaluation of respirator faceseal leaks using computational fluid dynamics and infrared imaging.

    PubMed

    Lei, Zhipeng; Yang, James; Zhuang, Ziqing; Roberge, Raymond

    2013-05-01

    This paper presents a computational fluid dynamics (CFD) simulation approach for the prediction of leakage between an N95 filtering facepiece respirator (FFR) and a headform and an infrared camera (IRC) method for validating the CFD approach. The CFD method was used to calculate leak location(s) and 'filter-to-faceseal leakage' (FTFL) ratio for 10 headforms and 6 FFRs.The computational geometry and leak gaps were determined from analysis of the contact simulation results between each headform-N95 FFR combination. The volumetric mesh was formed using a mesh generation method developed by the authors. The breathing cycle was described as a time-dependent profile of the air velocity through the nostril. Breathing air passes through both the FFR filter medium and the leak gaps. These leak gaps are the areas failing to achieve a seal around the circumference of the FFR. The CFD approach was validated by comparing facial temperatures and leak sites from IRC measurements with eight human subjects. Most leaks appear at the regions of the nose (40%) and right (26%) and left cheek (26%) sites. The results also showed that, with N95 FFR (no exhalation valves) use, there was an increase in the skin temperature at the region near the lip, which may be related to thermal discomfort. The breathing velocity and the viscous resistance coefficient of the FFR filter medium directly impacted the FTFL ratio, while the freestream flow did not show any impact on the FTFL ratio. The proposed CFD approach is a promising alternative method to study FFR leakage if limitations can be overcome.

  2. Nosepiece respiration monitor

    NASA Technical Reports Server (NTRS)

    Lavery, A. L.; Long, L. E.; Rice, N. E.

    1968-01-01

    Comfortable, inexpensive nosepiece respiration monitor produces rapid response signals to most conventional high impedance medical signal conditioners. The monitor measures respiration in a manner that produces a large signal with minimum delay.

  3. Respirator Fact Sheet

    MedlinePlus

    ... the respirator. If I have the right cartridges/filters for a certain hazard, and my mask fits, ... use and maintenance are essential. Will my cartridge/filter and respirator mask protect forever? Cartridges, filters, and ...

  4. Inflation with air via a facepiece for facilitating insertion of a nasogastric tube: a prospective, randomised, double-blind study.

    PubMed

    Gupta, D; Agarwal, A; Nath, S S; Goswami, D; Saraswat, V; Singh, P K

    2007-02-01

    Insertion of a nasogastric tube is a routine procedure but during anaesthesia it is often difficult and time consuming. One hundred and sixty adults undergoing elective surgery under general anaesthesia were randomly divided into two groups. After induction of anaesthesia, neuromuscular blockade and tracheal intubation, a nasogastric tube was inserted through the nose with the head of the patient in the neutral position, either with or without prior inflation with air via a facepiece attached to a self-inflating bag applied firmly with the face. Insertion of the nasogastric tube was successful in 75/78 (96%) following inflation compared with 54/80 (68%) without inflation (p<0.001). In four patients receiving inflation, a fibreoptic endoscope was passed as far as the upper oesophageal sphincter; this revealed opening of the upper oesophageal sphincter during inflation.

  5. Filter penetration and breathing resistance evaluation of respirators and dust masks.

    PubMed

    Ramirez, Joel; O'Shaughnessy, Patrick

    2017-02-01

    The primary objective of this study was to compare the filter performance of a representative selection of uncertified dust masks relative to the filter performance of a set of NIOSH-approved N95 filtering face-piece respirators (FFRs). Five different models of commercially available dust masks were selected for this study. Filter penetration of new dust masks was evaluated against a sodium chloride aerosol. Breathing resistance (BR) of new dust masks and FFRs was then measured for 120 min while challenging the dust masks and FFRs with Arizona road dust (ARD) at 25°C and 30% relative humidity. Results demonstrated that a wide range of maximum filter penetration was observed among the dust masks tested in this study (3-75% at the most penetrating particle size (p < 0.001). The breathing resistances of the unused FFRs and dust masks did not vary greatly (8-13 mm H 2 O) but were significantly different (p < 0.001). After dust loading there was a significant difference between the BR caused by the ARD dust layer on each FFR and dust mask. Microscopic analysis of the external layer of each dust mask and FFR suggests that different collection media in the external layer influences the development of the dust layer and therefore affects the increase in BR differently between the tested models. Two of the dust masks had penetration values < 5% and quality factors (0.26 and 0.33) comparable to those obtained for the two FFRs (0.23 and 0.31). However, the remaining three dust masks, those with penetration > 15%, had quality factors ranging between 0.04-0.15 primarily because their initial BR remained relatively high. These results indicate that some dust masks analysed during this research did not have an expected very low BR to compensate for their high penetration.

  6. Long-term exposure to residential ambient fine and coarse particulate matter and incident hypertension in post-menopausal women.

    PubMed

    Honda, Trenton; Eliot, Melissa N; Eaton, Charles B; Whitsel, Eric; Stewart, James D; Mu, Lina; Suh, Helen; Szpiro, Adam; Kaufman, Joel D; Vedal, Sverre; Wellenius, Gregory A

    2017-08-01

    Long-term exposure to ambient particulate matter (PM) has been previously linked with higher risk of cardiovascular events. This association may be mediated, at least partly, by increasing the risk of incident hypertension, a key determinant of cardiovascular risk. However, whether long-term exposure to PM is associated with incident hypertension remains unclear. Using national geostatistical models incorporating geographic covariates and spatial smoothing, we estimated annual average concentrations of residential fine (PM 2.5 ), respirable (PM 10 ), and course (PM 10-2.5 ) fractions of particulate matter among 44,255 post-menopausal women free of hypertension enrolled in the Women's Health Initiative (WHI) clinical trials. We used time-varying Cox proportional hazards models to evaluate the association between long-term average residential pollutant concentrations and incident hypertension, adjusting for potential confounding by sociodemographic factors, medical history, neighborhood socioeconomic measures, WHI study clinical site, clinical trial, and randomization arm. During 298,383 person-years of follow-up, 14,511 participants developed incident hypertension. The adjusted hazard ratios per interquartile range (IQR) increase in PM 2.5 , PM 10 , and PM 10-2.5 were 1.13 (95% CI: 1.08, 1.17), 1.06 (1.03, 1.10), and 1.01 (95% CI: 0.97, 1.04), respectively. Statistically significant concentration-response relationships were identified for PM 2.5 and PM 10 fractions. The association between PM 2.5 and hypertension was more pronounced among non-white participants and those residing in the Northeastern United States. In this cohort of post-menopausal women, ambient fine and respirable particulate matter exposures were associated with higher incidence rates of hypertension. These results suggest that particulate matter may be an important modifiable risk factor for hypertension. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Health effects of ambient levels of respirable particulate matter (PM) on healthy, young-adult population

    NASA Astrophysics Data System (ADS)

    Shaughnessy, William J.; Venigalla, Mohan M.; Trump, David

    2015-12-01

    There is an absence of studies that define the relationship between ambient particulate matter (PM) levels and adverse health outcomes among the young and healthy adult sub-group. In this research, the relationship between exposures to ambient levels of PM in the 10 micron (PM10) and 2.5 micron (PM2.5) size fractions and health outcomes in members of the healthy, young-adult subgroup who are 18-39 years of age was examined. Active duty military personnel populations at three strategically selected military bases in the United States were used as a surrogate to the control group. Health outcome data, which consists of the number of diagnoses for each of nine International Classification of Diseases, 9th Revision (ICD-9) categories related to respiratory illness, were derived from outpatient visits at each of the three military bases. Data on ambient concentrations of particulate matter, specifically PM10 and PM2.5, were obtained for these sites. The health outcome data were correlated and regressed with the PM10 and PM2.5 data, and other air quality and weather-related data on a daily and weekly basis for the period 1998 to 2004. Results indicate that at Fort Bliss, which is a US Environmental Protection Agency designated non-attainment area for PM10, a statistically significant association exists between the weekly-averaged number of adverse health effects in the young and healthy adult population and the corresponding weekly-average ambient PM10 concentration. A least squares regression analysis was performed on the Fort Bliss data sets indicated that the health outcome data is related to several environmental parameters in addition to PM10. Overall, the analysis estimates a .6% increase in the weekly rate of emergency room visits for upper respiratory infections for every 10 μg/m3 increase in the weekly-averaged PM10 concentration above the mean. The findings support the development of policy and guidance opportunities that can be developed to mitigate exposures

  8. Community airborne particulate matter from mining for sand used as hydraulic fracturing proppant.

    PubMed

    Peters, Thomas M; O'Shaughnessy, Patrick T; Grant, Ryan; Altmaier, Ralph; Swanton, Elizabeth; Falk, Jeffrey; Osterberg, David; Parker, Edith; Wyland, Nancy G; Sousan, Sinan; Stark, Aimee Liz; Thorne, Peter S

    2017-12-31

    Field and laboratory studies were conducted to evaluate the impact of proppant sand mining and processing activities on community particulate matter (PM) concentrations. In field studies outside 17 homes within 800m of sand mining activities (mining, processing, and transport), respirable (PM 4 ) crystalline silica concentrations were low (<0.4μg/m 3 ) with crystalline silica detected on 7 samples (2% to 4% of mass). In long-term monitoring at 6 homes within 800m of sand mining activities, the highest daily mean PM concentrations observed were 14.5μg/m 3 for PM 2.5 and 37.3μg/m 3 for PM 10 , although infrequent (<3% of time), short-term elevated PM concentrations occurred when wind blew over the facility. In laboratory studies, aerosolized sand was shown to produce respirable-sized particles, containing 6% to 19% crystalline silica. Dispersion modeling of a mine and processing facility indicated that PM 10 can exceed standards short distances (<40m) beyond property lines. Lastly, fence-line PM and crystalline silica concentrations reported to state agencies were substantially below regulatory or guideline values, although several excursions were observed for PM 10 when winds blew over the facility. Taken together, community exposures to airborne particulate matter from proppant sand mining activities at sites similar to these appear to be unlikely to cause chronic adverse health conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Soil Respiration And Respiration Partitioning In An Oak-Savannah With A History Of Fertilization

    NASA Astrophysics Data System (ADS)

    Morris, K. A.; Nair, R.; Schrumpf, M.; Migliavacca, M.

    2017-12-01

    Soil respiration is a combination of autotrophic and heterotrophic components. These components have different controls and structurally complex ecosystems such as oak-savannahs offer an opportunity to study strongly contrasting conditions (ie., soil from under trees versus open areas) in an environment with similar soil mineralogy and climatic patterns. To measure respiration coming from plant roots, fungal hyphae, and free-living microbes we established stations of soil cores comprised of three selectively permeable meshes under tree canopies and in open grassy areas of a Holm Oak (Quercus ilex) savannah in Extremadura, Spain. Large plots of this ecosystem had previously been fertilized as part of a stoichiometeric imbalance study (in 2015). Stations were installed in Dec. 2016 within four plots; control, N added, P added, and N+P added. Respiration from cores was measured in campaigns at key phenological stages with a portable Li-Cor 8100A unit. Six months after installation > 50% of soil respiration was attributable to free-living microbes. There is a persistent effect of the prior fertilization, resulting in increased soil respiration in open areas regardless of fertilizer type, while respiration from under tree canopies had a varied response. Soil under tree canopies showed distinct sensitivity to stoichiometric imbalance, meaning that addition of N or P alone either did not change respiration or decreased it slightly, while N+P stimulated respiration. We determined that respiration from free-living microbes is a major component of soil respiration even in the most active plant growing season. However, because of the lag between the time of fertilization and the time of measurement, it not possible to say whether treatment responses are due solely to nutrient status of the soil or whether changes in plant biomass and species composition also play a role. Additional work planned at the site will shed light on this uncertainty as well as the contribution of

  10. Does the increased air humidity affect soil respiration and carbon stocks?

    NASA Astrophysics Data System (ADS)

    Kukumägi, Mai; Celi, Luisella; Said-Pullicino, Daniel; Kupper, Priit; Sõber, Jaak; Lõhmus, Krista; Kutti, Sander; Ostonen, Ivika

    2013-04-01

    Climate manipulation experiments at ecosystem-scale enable us to simulate, investigate and predict changes in carbon balance of forest ecosystems. Considering the predicted increase in air humidity and precipitation for northern latitudes, this work aimed at investigating the effect of increased air humidity on soil respiration, distribution of soil organic matter (SOM) among pools having different turnover times, and microbial, fine root and rhizome biomass. The study was carried out in silver birch (Betula pendula Roth.) and hybrid aspen (Populus tremula L. × P. tremuloides Michx.) stands in a Free Air Humidity Manipulation (FAHM) experimental facility containing three humidified (H; on average 7% above current ambient levels since 2008) and three control (C) plots. Soil respiration rates were measured monthly during the growing season using a closed dynamic chamber method. Density fractionation was adopted to separate SOM into two light fractions (free and aggregate-occluded particulate organic matter, fPOM and oPOM respectively), and one heavy fraction (mineral-associated organic matter, MOM). The fine root and rhizome biomass and microbial data are presented for silver birch stands only. In 2011, after 4 growing seasons of humidity manipulation soil organic carbon contents were significantly higher in C plots than H plot (13.5 and 12.5 g C kg-1, respectively), while soil respiration tended to be higher in the latter. Microbial biomass and basal respiration were 13 and 14% higher in H plots than in the C plots, respectively. Twice more fine roots of trees were estimated in H plots, while the total fine root and rhizome biomass (tree + understory) was similar in C and H plots. Fine root turnover was higher for both silver birch and understory roots in H plots. Labile SOM light fractions (fPOM and oPOM) were significantly smaller in H plots with respect to C plots (silver birch and hybrid aspen stands together), whereas no differences were observed in the

  11. The Diesel Exhaust in Miners Study: III. Interrelations between respirable elemental carbon and gaseous and particulate components of diesel exhaust derived from area sampling in underground non-metal mining facilities.

    PubMed

    Vermeulen, Roel; Coble, Joseph B; Yereb, Daniel; Lubin, Jay H; Blair, Aaron; Portengen, Lützen; Stewart, Patricia A; Attfield, Michael; Silverman, Debra T

    2010-10-01

    Diesel exhaust (DE) has been implicated as a potential lung carcinogen. However, the exact components of DE that might be involved have not been clearly identified. In the past, nitrogen oxides (NO(x)) and carbon oxides (CO(x)) were measured most frequently to estimate DE, but since the 1990s, the most commonly accepted surrogate for DE has been elemental carbon (EC). We developed quantitative estimates of historical exposure levels of respirable elemental carbon (REC) for an epidemiologic study of mortality, particularly lung cancer, among diesel-exposed miners by back-extrapolating 1998-2001 REC exposure levels using historical measurements of carbon monoxide (CO). The choice of CO was based on the availability of historical measurement data. Here, we evaluated the relationship of REC with CO and other current and historical components of DE from side-by-side area measurements taken in underground operations of seven non-metal mining facilities. The Pearson correlation coefficient of the natural log-transformed (Ln)REC measurements with the Ln(CO) measurements was 0.4. The correlation of REC with the other gaseous, organic carbon (OC), and particulate measurements ranged from 0.3 to 0.8. Factor analyses indicated that the gaseous components, including CO, together with REC, loaded most strongly on a presumed 'Diesel exhaust' factor, while the OC and particulate agents loaded predominantly on other factors. In addition, the relationship between Ln(REC) and Ln(CO) was approximately linear over a wide range of REC concentrations. The fact that CO correlated with REC, loaded on the same factor, and increased linearly in log-log space supported the use of CO in estimating historical exposure levels to DE.

  12. The Diesel Exhaust in Miners Study: III. Interrelations between Respirable Elemental Carbon and Gaseous and Particulate Components of Diesel Exhaust derived from Area Sampling in Underground Non-metal Mining Facilities

    PubMed Central

    Vermeulen, Roel; Coble, Joseph B.; Yereb, Daniel; Lubin, Jay H.; Blair, Aaron; Portengen, Lützen; Stewart, Patricia A.; Attfield, Michael; Silverman, Debra T.

    2010-01-01

    Diesel exhaust (DE) has been implicated as a potential lung carcinogen. However, the exact components of DE that might be involved have not been clearly identified. In the past, nitrogen oxides (NOx) and carbon oxides (COx) were measured most frequently to estimate DE, but since the 1990s, the most commonly accepted surrogate for DE has been elemental carbon (EC). We developed quantitative estimates of historical exposure levels of respirable elemental carbon (REC) for an epidemiologic study of mortality, particularly lung cancer, among diesel-exposed miners by back-extrapolating 1998–2001 REC exposure levels using historical measurements of carbon monoxide (CO). The choice of CO was based on the availability of historical measurement data. Here, we evaluated the relationship of REC with CO and other current and historical components of DE from side-by-side area measurements taken in underground operations of seven non-metal mining facilities. The Pearson correlation coefficient of the natural log-transformed (Ln)REC measurements with the Ln(CO) measurements was 0.4. The correlation of REC with the other gaseous, organic carbon (OC), and particulate measurements ranged from 0.3 to 0.8. Factor analyses indicated that the gaseous components, including CO, together with REC, loaded most strongly on a presumed ‘Diesel exhaust’ factor, while the OC and particulate agents loaded predominantly on other factors. In addition, the relationship between Ln(REC) and Ln(CO) was approximately linear over a wide range of REC concentrations. The fact that CO correlated with REC, loaded on the same factor, and increased linearly in log–log space supported the use of CO in estimating historical exposure levels to DE. PMID:20876234

  13. REGULATORY MECHANISMS OF CELLULAR RESPIRATION

    PubMed Central

    Barron, E. S. Guzman; Nelson, Leonard; Ardao, Maria Isabel

    1948-01-01

    Oxidizing agents of sulfhydryl groups such as iodosobenzoate, alkylating agents such as iodoacetamide, and mercaptide-forming agents such as cadmium chloride, mercuric chloride, p-chloromercuribenzoate, sodium arsenite, and p-carboxyphenylarsine oxide, added in small concentrations to a suspension of sea urchin sperm produced an increase in respiration. When the concentration was increased there was an inhibition. These effects are explained by postulating the presence in the cells of two kinds of sulfhydryl groups: soluble sulfhydryl groups, which regulate cellular respiration, and fixed sulfhydryl groups, present in the protein moiety of enzymes. Small concentrations of sulfhydryl reagents combine only with the first, thus producing an increase in respiration; when the concentration is increased, the fixed sulfhydryl groups are also attacked and inhibition of respiration is the consequence. Other inhibitors of cell respiration, such as cyanide and urethanes, which do not combine with —SH groups, did not stimulate respiration in small concentration. PMID:18891144

  14. Interpreting, measuring, and modeling soil respiration

    Treesearch

    Michael G. Ryan; Beverly E. Law

    2005-01-01

    This paper reviews the role of soil respiration in determining ecosystem carbon balance, and the conceptual basis for measuring and modeling soil respiration. We developed it to provide background and context for this special issue on soil respiration and to synthesize the presentations and discussions at the workshop. Soil respiration is the largest component of...

  15. Establishing aeolian particulate 'fingerprints' in an airport environment using magnetic measurements and SEM/EDAX

    NASA Astrophysics Data System (ADS)

    Jones, Sue; Hoon, Stephen R.; Richardson, Nigel; Bennett, Michael

    2016-04-01

    The significant increase in global air travel which has occurred during the last fifty years has generated growing concern regarding the potential impacts associated with increasing emissions of particulate matter (PM) from aviation activity on health and the environment. PM within the airport environment, in particular, may be derived from a wide range of potential sources including aircraft; vehicles; ground support equipment and buildings. In order to investigate and remediate potential problem sources, it is important to be able to identify characteristic particulate 'fingerprints' which would allow source attribution, particularly respirable particulates. To date the identification of such 'fingerprints' has remained elusive but remains a key research priority for the aviation industry (Webb et al, 2008). In previous PM studies, environmental magnetism has been used as a successful technique for discriminating between different emission types and particulate sources in both urban and industrial environments (e.g. Hunt et al 1984; Lecoanet et al 2003, Jones et al 2015). Environmental magnetism is a non-destructive and relatively rapid technique involving the use of non-directional, rock magnetic measurements to characterise the mineral magnetic properties of natural and anthropogenic materials. In other studies scanning electron microscopy (SEM) has also been used as an effective characterisation technique for the investigation of grain size and morphology of PM derived from vehicle emissions (e.g. Bucko et al 2010) and fossil fuel combustion sources (Kim et al 2009). In this study, environmental magnetic measurements and SEM/EDAX have been used to characterise dusts from specific aircraft sources including engines, brakes and tyres. Furthermore, these methods have also been applied to runway (both hard and grass covered surfaces), taxiway and apron dusts collected during extensive environmental sampling at Manchester International Airport, UK in order to

  16. Nitrogen controls spatial and temporal variability of substrate-induced respiration within seven years of bare fallow

    NASA Astrophysics Data System (ADS)

    Meyer, Nele; Bornemann, Ludger; Welp, Gerhard; Amelung, Wulf

    2015-04-01

    Bare fallow management goes along with lacking supply of new C sources; yet, little is known on the spatio-temporal controls of microbial adaptation processes. Here we hypothesized that microbial activity parameters decline upon bare fallow but that their spatial patterns are increasingly controlled by nutrient status as fallow management proceeds. To test these hypotheses, we investigated spatial and temporal patterns of substrate-induced respiration (SIR) and basal respiration curves in an arable field after 1, 3, and 7 years of bare fallow but with large within-field heterogeneity of physicochemical soil parameters. The analyses comprised the contents of SOC, mineral nitrogen (Nmin), particulate organic matter (POM), texture of the fine earth, and the proportion of rock fragments as well as basal respiration and several SIR fitting parameters (microbial biomass, microbial growth rates, peak respiration rates, cumulative CO2 release) each with and without additions of mineral N and P. We also repeated substrate (i.e. glucose) additions following the first SIR measurement. The results revealed that most respiration parameters like basal respiration, microbial biomass, and growth rates showed no or inconsistent responses to spatial and temporal patterns of basic soil properties like SOC, Nmin or texture. However, bare fallow changed the shape of the SIR curves; it developed two distinct microbial growth peaks at advanced stages of fallow, i.e. a delayed CO2 release. Likewise, the maximum respiration rate during the first growth phase declined during 7 years of fallow by 47% but its spatial distribution was always correlated with Nmin contents (r = 0.43 - 0.79). The nutrient additions suggested that these changes in SIR curves were caused by N deficiency; the first peak increased after N additions while the second growth phase diminished. Intriguingly, a repeated glucose addition had a similar effect on the SIR curves as the glucose+N addition. Thus, N deficiency

  17. Tobacco Smoke: Involvement of Reactive Oxygen Species and Stable Free Radicals in Mechanisms of Oxidative Damage, Carcinogenesis and Synergistic Effects with Other Respirable Particles

    PubMed Central

    Valavanidis, Athanasios; Vlachogianni, Thomais; Fiotakis, Konstantinos

    2009-01-01

    Tobacco smoke contains many toxic, carcinogenic and mutagenic chemicals, as well as stable and unstable free radicals and reactive oxygen species (ROS) in the particulate and the gas phase with the potential for biological oxidative damage. Epidemiological evidence established that smoking is one of the most important extrinsic factor of premature morbidity and mortality. The objective of this study was to investigate oxidative and carcinogenic mechanisms of tobacco and synergistic action with other respirable particles in the respiratory system of smokers. Electron Paramagnetic Resonance (EPR) and spin-trapping techniques were used to study stable free radicals in the cigarette tar, and unstable superoxide anion (O2•−) and hydroxyl (HO•) radicals in the smoke Results showed that the semiquinone radical system has the potential for redox recycling and oxidative action. Further, results proved that aqueous cigarette tar (ACT) solutions can generate adducts with DNA nucleobases, particularly the mutagenic 8-hydroxy-2’-deoxyguanosine (a biomarker for carcinogenesis). Also, we observed synergistic effects in the generation of HO•, through the Fenton reaction, with environmental respirable particles (asbestos fibres, coal dust, etc.) and ambient particulate matter (PM), such as PM10, PM2.5 and diesel exhaust particles (DEP). The highest synergistic effects was observed with the asbestos fibres (freshly grounded), PM2.5 and DEP. Finally, we discuss results from our previous study of conventional cellulose acetate filters and “bio-filters” with hemoglobin impregnated activated carbon, which showed that these filters do not substantially alter the free radical content of smoke in the particulate and in the gaseous phase. PMID:19440393

  18. Tobacco smoke: involvement of reactive oxygen species and stable free radicals in mechanisms of oxidative damage, carcinogenesis and synergistic effects with other respirable particles.

    PubMed

    Valavanidis, Athanasios; Vlachogianni, Thomais; Fiotakis, Konstantinos

    2009-02-01

    Tobacco smoke contains many toxic, carcinogenic and mutagenic chemicals, as well as stable and unstable free radicals and reactive oxygen species (ROS) in the particulate and the gas phase with the potential for biological oxidative damage. Epidemiological evidence established that smoking is one of the most important extrinsic factor of premature morbidity and mortality. The objective of this study was to investigate oxidative and carcinogenic mechanisms of tobacco and synergistic action with other respirable particles in the respiratory system of smokers. Electron Paramagnetic Resonance (EPR) and spin-trapping techniques were used to study stable free radicals in the cigarette tar, and unstable superoxide anion (O2 (*-)) and hydroxyl (HO(*)) radicals in the smoke Results showed that the semiquinone radical system has the potential for redox recycling and oxidative action. Further, results proved that aqueous cigarette tar (ACT) solutions can generate adducts with DNA nucleobases, particularly the mutagenic 8-hydroxy-2'-deoxyguanosine (a biomarker for carcinogenesis). Also, we observed synergistic effects in the generation of HO(*), through the Fenton reaction, with environmental respirable particles (asbestos fibres, coal dust, etc.) and ambient particulate matter (PM), such as PM(10), PM(2.5) and diesel exhaust particles (DEP). The highest synergistic effects was observed with the asbestos fibres (freshly grounded), PM(2.5) and DEP. Finally, we discuss results from our previous study of conventional cellulose acetate filters and "bio-filters" with hemoglobin impregnated activated carbon, which showed that these filters do not substantially alter the free radical content of smoke in the particulate and in the gaseous phase.

  19. Mesozooplankton production, grazing and respiration in the Bay of Bengal: Implications for net heterotrophy

    NASA Astrophysics Data System (ADS)

    Fernandes, Veronica; Ramaiah, N.

    2016-03-01

    Mesozooplankton samples were collected from the mixed layer along a central (along 88°E) and a western transect in the Bay of Bengal during four seasons covered between 2001 and 2006 in order to investigate spatio-temporal variability in their biomass. At these stations, grazing and respiration rates were measured from live zooplankton hauled in from the surface during December 2005. Akin to the mesozooplankton "paradox" in the central and eastern Arabian Sea, biomass in the mixed layer was more or less invariant in the central and western Bay of Bengal, even as the chl a showed marginal temporal variation. By empirical equation, the mesozooplankton production rate calculated to be 70-246 mg C m- 2 d- 1 is on par with the Arabian Sea. Contrary to the conventional belief, mesozooplankton grazing impact was up to 83% on primary production (PP). Low PP coupled with very high zooplankton production (70% of PP) along with abundant bacterial production (50% of the PP; Ramaiah et al., 2009) is likely to render the Bay of Bengal net heterotrophic, especially during the spring intermonsoon. Greater estimates of fecal pellet-carbon egestion by mesozooplankton compared to the average particulate organic carbon flux in sediment traps, implies that much of the matter is recycled by heterotrophic communities in the mixed layer facilitating nutrient regeneration for phytoplankton growth. We also calculated that over a third of the primary production is channelized for basin-wide zooplankton respiration that accounts for 52 Mt C annually. In the current scenario of global warming, if low (primary) productive warm pools like the Bay of Bengal continue to be net heterotrophic, negative implications like enhanced emission of CO2 to the atmosphere, increased particulate flux to the deeper waters and greater utilization of dissolved oxygen resulting in expansion of the existing oxygen minimum zone are imminent.

  20. Hybrid respiration-signal conditioner

    NASA Technical Reports Server (NTRS)

    Rinard, G. A.; Steffen, D. A.; Sturm, R. E.

    1979-01-01

    Hybrid impedance-pneumograph and respiration-rate signal conditioner element of hand-held vital signs monitor measures changes in impedance of chest during breathing cycle and generates analog respiration signal as output along with synchronous square wave that can be monitored by breath-rate processor.

  1. Lung Function in Rural Guatemalan Women Before and After a Chimney Stove Intervention to Reduce Wood Smoke Exposure: Results From the Randomized Exposure Study of Pollution Indoors and Respiratory Effects and Chronic Respiratory Effects of Early Childhood Exposure to Respirable Particulate Matter Study.

    PubMed

    Guarnieri, Michael; Diaz, Esperanza; Pope, Daniel; Eisen, Ellen A; Mann, Jennifer; Smith, Kirk R; Smith-Sivertsen, Tone; Bruce, Nigel G; Balmes, John R

    2015-11-01

    COPD is the third most frequent cause of death globally, with much of this burden attributable to household biomass smoke exposure in developing countries. As biomass smoke exposure is also associated with cardiovascular disease, lower respiratory infection, lung cancer, and cataracts, it presents an important target for public health intervention. Lung function in Guatemalan women exposed to wood smoke from open fires was measured throughout the Randomized Exposure Study of Pollution Indoors and Respiratory Effects (RESPIRE) stove intervention trial and continued during the Chronic Respiratory Effects of Early Childhood Exposure to Respirable Particulate Matter (CRECER) cohort study. In RESPIRE, early stove households received a chimney woodstove at the beginning of the 18-month trial, and delayed stove households received a stove at trial completion. Personal exposure to wood smoke was assessed with exhaled breath carbon monoxide (CO) and personal CO tubes. Change in lung function between intervention groups and as a function of wood smoke exposure was assessed using random effects models. Of 306 women participating in both studies, acceptable spirometry was collected in 129 early stove and 136 delayed stove households (n = 265), with a mean follow-up of 5.6 years. Despite reduced wood smoke exposures in early stove households, there were no significant differences in any of the measured spirometric variables during the study period (FEV1, FVC, FEV1/FVC ratio, and annual change) after adjustment for confounding. In these young Guatemalan women, there was no association between lung function and early randomization to a chimney stove or personal wood smoke exposure. Future stove intervention trials should incorporate cleaner stoves, longer follow-up, or potentially susceptible groups to identify meaningful differences in lung function.

  2. [Dark respiration of terrestrial vegetations: a review].

    PubMed

    Sun, Jin-Wei; Yuan, Feng-Hui; Guan, De-Xin; Wu, Jia-Bing

    2013-06-01

    The source and sink effect of terrestrial plants is one of the hotspots in terrestrial ecosystem research under the background of global change. Dark respiration of terrestrial plants accounts for a large fraction of total net carbon balance, playing an important role in the research of carbon cycle under global climate change. However, there is little study on plant dark respiration. This paper summarized the physiological processes of plant dark respiration, measurement methods of the dark respiration, and the effects of plant biology and environmental factors on the dark respiration. The uncertainty of the dark respiration estimation was analyzed, and the future hotspots of related researches were pointed out.

  3. Contribution of bacterial respiration to plankton respiration from 50°N to 44°S in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    García-Martín, E. E.; Aranguren-Gassis, M.; Hartmann, M.; Zubkov, M. V.; Serret, P.

    2017-11-01

    Marine bacteria play an important role in the global cycling of carbon and therefore in climate regulation. However, the paucity of direct measurements means that our understanding of the magnitude and variability of bacterial respiration in the ocean is poor. Estimations of respiration in the 0.2-0.8 μm size-fraction (considered as bacterial respiration), total plankton community respiration, and the contribution of bacterial respiration to total plankton community respiration were made along two latitudinal transects in the Atlantic Ocean (ca. 50°N-44°S) during 2010 and 2011. Two different methodologies were used: determination of changes in dissolved O2 concentration after standard 24 h dark bottle incubations, and measurements of in vivo reduction of 2-(ρ-iodophenyl)-3-(ρ-nitrophenyl)-5phenyl tetrazolium salt (INT). There was an overall significant correlation (r = 0.44, p < 0.0001, n = 90) between the rates of community respiration estimated by both methods. Depth-integrated community respiration varied as much as threefold between regions. Maximum rates occurred in waters of the western European shelf and Patagonian shelf, and minimum rates in the North and South oligotrophic gyres. Depth-integrated bacterial respiration followed the same pattern as community respiration. There was a significantly higher cell-specific bacterial respiration in the northern subtropical gyre than in the southern subtropical gyre which suggests that bacterial carbon turnover is faster in the northern gyre. The relationships between plankton respiration and physicochemical and biological variables were different in different years. In general, INTT was correlated to both chlorophyll-a and bacterial abundance, while INT0.2-0.8 was only correlated with bacterial abundance. However, in 2010 INTT and INT0.2-0.8 were also correlated with temperature and primary production while in 2011 they were correlated with nitrate + nitrite concentration. The bacterial contribution to depth

  4. Does Short-term Litter Input Manipulation Affect Soil Respiration and the Carbon-isotopic Signature of Soil Respired CO2

    NASA Astrophysics Data System (ADS)

    Cheng, X.; Wu, J.

    2016-12-01

    Global change greatly alters the quality and quantity of plant litter inputs to soils, and further impacts soil organic matter (SOM) dynamics and soil respiration. However, the process-based understanding of how soil respiration may change with future shift in litter input is not fully understood. The Detritus Input and Removal Treatment (DIRT) experiment was conducted in coniferous forest (Platycladus orientalis (Linn.) Franco) ecosystem of central China to investigate the impact of above- and belowground litter input on soil respiration and the carbon-isotopic signature of soil respired CO2. Short-term (1-2 years) litter input manipulation significantly affected soil respiration, based on annual flux values, soil respiration was 31.9%, 20.5% and 37.2% lower in no litter (NL), no root (NR) and no input (NRNL), respectively, compared to control (CK). Whereas double litter (DL) treatment increased soil respiration by 9.1% compared to CK. The recalcitrance index of carbon (RIC) and the relative abundance of fungi increased under litter removal or root exclusion treatment (NL, NR and NRNL) compared to CK. Basal soil respiration was positively related to liable C and microbial biomass and negatively related to RIC and fungi to bacteria (F: B) ratio. The carbon-isotopic signature of soil respired CO2 enriched under litter removal and no input treatment, and slightly depleted under litter addition treatment compared to CK. Our results suggest that short-term litter input manipulation can affect the soil respiration by altering substrate availability and microbial community structure, and also impact the carbon-isotopic signature of soil respired CO2 possibly duo to change in the component of soil respiration and soil microclimate.

  5. Effects of respirator use on worker performance

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cardarelli, R.

    1995-03-01

    In 1993, EPRI funded Yankee Atomic Electric Company to examine the effects of respirator use on worker efficiency. Phase I of Yankee`s effort was to develop a study design to determine respirator effects. Given success in Phase I, a larger population will be tested to determine if a stasitically significant respirator effect on performance can be measured. This paper summarizes the 1993 EPRI/Yankee Respirator Effects of Pilot Study, and describes the study design for the 1994 EPRI/Yankee Respirator Study to be conducted at the Oyster Creek Nuclear Power Plant. Also described is a summary of respirator effect studies that havemore » been conducted during the last ten (10) years.« less

  6. Respiratory source control using surgical masks with nanofiber media.

    PubMed

    Skaria, Shaji D; Smaldone, Gerald C

    2014-07-01

    Potentially infected individuals ('source') are sometimes encouraged to use face masks to reduce exposure of their infectious aerosols to others ('receiver'). To improve compliance with Respiratory Source Control via face mask and therefore reduce receiver exposure, a mask should be comfortable and effective. We tested a novel face mask designed to improve breathability and filtration using nanofiber filtration. Using radiolabeled test aerosols and a calibrated exposure chamber simulating source to receiver interaction, facepiece function was measured with a life-like ventilated manikin model. Measurements included mask airflow resistance (pressure difference during breathing), filtration, (mask capture of exhaled radiolabeled test aerosols), and exposure (the transfer of 'infectious' aerosols from the 'source' to a 'receiver'). Polydisperse aerosols were measured at the source with a mass median aerodynamic diameter of 0.95 µm. Approximately 90% of the particles were <2.0 µm. Tested facepieces included nanofiber prototype surgical masks, conventional surgical masks, and for comparison, an N95-class filtering facepiece respirator (commonly known as an 'N95 respirator'). Airflow through and around conventional surgical face mask and nanofiber prototype face mask was visualized using Schlieren optical imaging. Airflow resistance [ΔP, cmH2O] across sealed surgical masks (means: 0.1865 and 0.1791 cmH2O) approached that of the N95 (mean: 0.2664 cmH2O). The airflow resistance across the nanofiber face mask whether sealed or not sealed (0.0504 and 0.0311 cmH2O) was significantly reduced in comparison. In addition, 'infected' source airflow filtration and receiver exposure levels for nanofiber face masks placed on the source were comparable to that achieved with N95 placed on the source; 98.98% versus 82.68% and 0.0194 versus 0.0557, respectively. Compared to deflection within and around the conventional face masks, Schlieren optical imaging demonstrated enhanced

  7. Particulate matter in cigarette smoke increases ciliary axoneme beating through mechanical stimulation.

    PubMed

    Navarrette, Chelsea R; Sisson, Joseph H; Nance, Elizabeth; Allen-Gipson, Diane; Hanes, Justin; Wyatt, Todd A

    2012-06-01

    The lung's ability to trap and clear foreign particles via the mucociliary elevator is an important mechanism for protecting the lung against respirable irritants and microorganisms. Although cigarette smoke (CS) exposure and particulate inhalation are known to alter mucociliary clearance, little is known about how CS and nanoparticles (NPs) modify cilia beating at the cytoskeletal infrastructure, or axonemal, level. We used a cell-free model to introduce cigarette smoke extract (CSE) and NPs with variant size and surface chemistry to isolated axonemes and measured changes in ciliary motility. We hypothesized that CSE would alter cilia beating and that alterations in ciliary beat frequency (CBF) due to particulate matter would be size- and surface chemistry-dependent. Demembranated axonemes were isolated from ciliated bovine tracheas and exposed to adenosine triphosphate (ATP) to initiate motility. CBF was measured in response to 5% CSE, CSE filtrate, and carboxyl-modified (COOH), sulphate (SO(4))-modified (sulfonated), or PEG-coated polystyrene (PS) latex NPs ranging in size from 40 nm to 500 nm. CSE concentrations as low as 5% resulted in rapid, significant stimulation of CBF (p<0.05 vs. baseline control). Filtering CSE through a 0.2-μm filter attenuated this effect. Introduction of sulphate-modified PS beads ~300 nm in diameter resulted in a similar increase in CBF above baseline ATP levels. Uncharged, PEG-coated beads had no effect on CBF regardless of size. Similarly, COOH-coated particles less than 200 nm in diameter did not alter ciliary motility. However, COOH-coated PS particles larger than 300 nm increased CBF significantly and increased the number of motile points. These data show that NPs, including those found in CSE, mechanically stimulate axonemes in a size- and surface chemistry-dependent manner. Alterations in ciliary motility due to physicochemical properties of NPs may be important for inhalational lung injury and efficient drug delivery of

  8. Basic study on the most relaxing respiration period in children to aid the development of a respiration-leading stuffed toy.

    PubMed

    Uratani, Hiroki; Yoshino, Kohzoh; Ohsuga, Mieko

    2014-01-01

    Following natural disasters, accidents, and shocking incidents, some children experience post-traumatic stress disorder (PTSD). The respiration control method, which relaxes the body and mind, may efficiently prevent PTSD. Therefore, we developed a stuffed toy that leads children's respiration using the up-and-down movement of the abdomen to help them relax. We investigated the most appropriate respiration period for children's relaxation. Data from studies on heart rate variability (HRV) biofeedback training suggest that breathing at the respiration period at which HRV is the highest is effective for improving chronic diseases. Therefore, we measured the relationship between the respiration period and physiological indices, including HRV. The participants were 10 children aged 5-12 years. HRV was the highest at a 10-12-s respiration period in all 10 children. However, the most suitable respiration period for smooth breathing and relaxation was different from that at which HRV is the highest. Therefore, the most relaxing respiration periods for children need to be determined by indices other than HRV.

  9. An intelligent FFR with a self-adjustable ventilation fan.

    PubMed

    Zhou, Song; Li, Hui; Shen, Shengnan; Li, Siyu; Wang, Wei; Zhang, Xiaotie; Yang, James

    2017-11-01

    This article presents an intelligent Filtering Facepiece Respirator (FFR) with a self-adjustable ventilation fan for improved comfort. The ventilation fan with an intelligent control aims to reduce temperature, relative humidity, and CO 2 concentrations inside the facepiece. Compared with a previous version of the FFR, the advantage of this new FFR is the intelligent control of the fan's rotation speed based on the change in temperature and relative humidity in the FFR dead space. The design of the control system utilizes an 8-bit, ultra-low power STC15W404AS microcontroller (HongJin technology, Shenzhen, China), and adopts a high-precision AM2320 device (AoSong electronic, Guangzhou, China) as temperature and relative humidity sensor so that control of temperature and relative humidity is realized in real time within the FFR dead space. The ventilation fan is intelligently driven and runs on a rechargeable lithium battery with a power-save mode that provides a correspondingly longer operational time. Meanwhile, the design is simplistic. Two experiments were performed to determine the best location to place the fan.

  10. Changes in soil respiration components and their specific respiration along three successional forests in the subtropics

    DOE PAGES

    Han, Tianfeng; Liu, Juxiu; Wang, Gangsheng; ...

    2016-01-16

    1.Understanding how soil respiration components change with forest succession is critical for modelling and predicting soil carbon (C) processes and its sequestration below-ground. The specific respiration (a ratio of respiration to biomass) is increasingly being used as an indicator of forest succession conceptually based on Odum's theory of ecosystem development. However, the hypothesis that specific soil respiration declines with forest succession remains largely untested. 2.We used a trenching method to partition soil respiration into heterotrophic respiration and autotrophic respiration (R H and R A) and then evaluated the specific R H and specific R A in three successional forests inmore » subtropical China. 3.Our results showed a clear seasonality in the influence of forest succession on R H, with no significant differences among the three forests in the dry season but a higher value in the old-growth forest than the other two forests in the wet season. R A in the old-growth forest tended to be the highest among the three forests. Both the specific R H and specific R A decreased with the progressive maturity of three forests. 4.Lastly, our results highlight the importance of forest succession in determining the variation of R H in different seasons. With forest succession, soil microbes and plant roots become more efficient to conserve C resources, which would result in a greater proportion of C retained in soils.« less

  11. Thoracic and respirable particle definitions for human health risk assessment.

    PubMed

    Brown, James S; Gordon, Terry; Price, Owen; Asgharian, Bahman

    2013-04-10

    Particle size-selective sampling refers to the collection of particles of varying sizes that potentially reach and adversely affect specific regions of the respiratory tract. Thoracic and respirable fractions are defined as the fraction of inhaled particles capable of passing beyond the larynx and ciliated airways, respectively, during inhalation. In an attempt to afford greater protection to exposed individuals, current size-selective sampling criteria overestimate the population means of particle penetration into regions of the lower respiratory tract. The purpose of our analyses was to provide estimates of the thoracic and respirable fractions for adults and children during typical activities with both nasal and oral inhalation, that may be used in the design of experimental studies and interpretation of health effects evidence. We estimated the fraction of inhaled particles (0.5-20 μm aerodynamic diameter) penetrating beyond the larynx (based on experimental data) and ciliated airways (based on a mathematical model) for an adult male, adult female, and a 10 yr old child during typical daily activities and breathing patterns. Our estimates show less penetration of coarse particulate matter into the thoracic and gas exchange regions of the respiratory tract than current size-selective criteria. Of the parameters we evaluated, particle penetration into the lower respiratory tract was most dependent on route of breathing. For typical activity levels and breathing habits, we estimated a 50% cut-size for the thoracic fraction at an aerodynamic diameter of around 3 μm in adults and 5 μm in children, whereas current ambient and occupational criteria suggest a 50% cut-size of 10 μm. By design, current size-selective sample criteria overestimate the mass of particles generally expected to penetrate into the lower respiratory tract to provide protection for individuals who may breathe orally. We provide estimates of thoracic and respirable fractions for a variety of

  12. Thoracic and respirable particle definitions for human health risk assessment

    PubMed Central

    2013-01-01

    Background Particle size-selective sampling refers to the collection of particles of varying sizes that potentially reach and adversely affect specific regions of the respiratory tract. Thoracic and respirable fractions are defined as the fraction of inhaled particles capable of passing beyond the larynx and ciliated airways, respectively, during inhalation. In an attempt to afford greater protection to exposed individuals, current size-selective sampling criteria overestimate the population means of particle penetration into regions of the lower respiratory tract. The purpose of our analyses was to provide estimates of the thoracic and respirable fractions for adults and children during typical activities with both nasal and oral inhalation, that may be used in the design of experimental studies and interpretation of health effects evidence. Methods We estimated the fraction of inhaled particles (0.5-20 μm aerodynamic diameter) penetrating beyond the larynx (based on experimental data) and ciliated airways (based on a mathematical model) for an adult male, adult female, and a 10 yr old child during typical daily activities and breathing patterns. Results Our estimates show less penetration of coarse particulate matter into the thoracic and gas exchange regions of the respiratory tract than current size-selective criteria. Of the parameters we evaluated, particle penetration into the lower respiratory tract was most dependent on route of breathing. For typical activity levels and breathing habits, we estimated a 50% cut-size for the thoracic fraction at an aerodynamic diameter of around 3 μm in adults and 5 μm in children, whereas current ambient and occupational criteria suggest a 50% cut-size of 10 μm. Conclusions By design, current size-selective sample criteria overestimate the mass of particles generally expected to penetrate into the lower respiratory tract to provide protection for individuals who may breathe orally. We provide estimates of thoracic and

  13. 42 CFR 84.250 - Vinyl chloride respirators; description.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Vinyl chloride respirators; description. 84.250... Respirators § 84.250 Vinyl chloride respirators; description. Vinyl chloride respirators, including all... escape from vinyl chloride atmospheres containing adequate oxygen to support life, are described...

  14. Mitochondrial respiration is sensitive to cytoarchitectural breakdown.

    PubMed

    Kandel, Judith; Angelin, Alessia A; Wallace, Douglas C; Eckmann, David M

    2016-11-07

    An abundance of research suggests that cellular mitochondrial and cytoskeletal disruption are related, but few studies have directly investigated causative connections between the two. We previously demonstrated that inhibiting microtubule and microfilament polymerization affects mitochondrial motility on the whole-cell level in fibroblasts. Since mitochondrial motility can be indicative of mitochondrial function, we now further characterize the effects of these cytoskeletal inhibitors on mitochondrial potential, morphology and respiration. We found that although they did not reduce mitochondrial inner membrane potential, cytoskeletal toxins induced significant decreases in basal mitochondrial respiration. In some cases, basal respiration was only affected after cells were pretreated with the calcium ionophore A23187 in order to stress mitochondrial function. In most cases, mitochondrial morphology remained unaffected, but extreme microfilament depolymerization or combined intermediate doses of microtubule and microfilament toxins resulted in decreased mitochondrial lengths. Interestingly, these two particular exposures did not affect mitochondrial respiration in cells not sensitized with A23187, indicating an interplay between mitochondrial morphology and respiration. In all cases, inducing maximal respiration diminished differences between control and experimental groups, suggesting that reduced basal respiration originates as a largely elective rather than pathological symptom of cytoskeletal impairment. However, viability experiments suggest that even this type of respiration decrease may be associated with cell death.

  15. 42 CFR 84.130 - Supplied-air respirators; description.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Supplied-air respirators; description. 84.130... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.130 Supplied-air respirators; description. Supplied-air respirators, including all completely...

  16. 42 CFR 84.130 - Supplied-air respirators; description.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Supplied-air respirators; description. 84.130... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.130 Supplied-air respirators; description. Supplied-air respirators, including all completely...

  17. 42 CFR 84.197 - Respirator containers; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Respirator containers; minimum requirements. 84.197... Cartridge Respirators § 84.197 Respirator containers; minimum requirements. Respirators shall be equipped with a substantial, durable container bearing markings which show the applicant's name, the type and...

  18. 42 CFR 84.134 - Respirator containers; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Respirator containers; minimum requirements. 84.134... Respirators § 84.134 Respirator containers; minimum requirements. Supplied-air respirators shall be equipped with a substantial, durable container bearing markings which show the applicant's name, the type and...

  19. Particulate matter analysis at elementary schools in Curitiba, Brazil.

    PubMed

    Avigo, Devanir; Godoi, Ana F L; Janissek, Paulo R; Makarovska, Yaroslava; Krata, Agnieszka; Potgieter-Vermaak, Sanja; Alfoldy, Balint; Van Grieken, René; Godoi, Ricardo H M

    2008-06-01

    The particulate matter indoors and outdoors of the classrooms at two schools in Curitiba, Brazil, was characterised in order to assess the indoor air quality. Information concerning the bulk composition was provided by energy-dispersive x-ray fluorescence (EDXRF). From the calculated indoor/outdoor ratios and the enrichment factors it was observed that S-, Cl- and Zn-rich particles are of concern in the indoor environment. In the present research, the chemical compositions of individual particles were quantitatively elucidated, including low-Z components like C, N and O, as well as higher-Z elements, using automated electron probe microanalysis low Z EPMA. Samples were further analysed for chemical and morphological aspects, determining the particle size distribution and classifying them according to elemental composition associations. Five classes were identified based on major elemental concentrations: aluminosilicate, soot, organic, calcium carbonate and iron-rich particles. The majority of the respirable particulate matter found inside of the classroom was composed of soot, biogenic and aluminosilicate particles. In view of the chemical composition and size distribution of the aerosol particles, local deposition efficiencies in the human respiratory system were calculated revealing the deposition of soot at alveolar level. The results showed that on average 42% of coarse particles are deposited at the extrathoracic level, whereas 24% are deposited at the pulmonary region. The fine fraction showed a deposition rate of approximately 18% for both deposition levels.

  20. Can we distinguish autotrophic respiration from heterotrophic respiration in a field site using high temporal resolution CO2 flux measurements?

    NASA Astrophysics Data System (ADS)

    Biro, Beatrice; Berger, Sina; Praetzel, Leandra; Blodau, Christian

    2016-04-01

    The processes behind C-cycling in peatlands are important to understand for assessing the vulnerability of peatlands as carbon sinks under changing climate conditions. Especially boreal peatlands are likely to underlie strong alterations in the future. It is expected that C-pools that are directly influenced by vegetation and water table fluctuations can be easily destabilized. The CO2 efflux through respiration underlies autotrophic and heterotrophic processes that show different feedbacks on changing environmental conditions. In order to understand the respiration fluxes better for more accurate modelling and prognoses, the determination of the relative importance of different respiration sources is necessary. Earlier studies used e.g. exfoliation experiments, incubation experiments or modelling approaches to estimate the different respiration sources for the total ecosystem respiration (Reco). To further the understanding in this topic, I want to distinguish autotrophic and heterotrophic respiration using high temporal resolution measurements. The study site was selected along a hydrological gradient in a peatland in southern Ontario (Canada) and measurements were conducted from May to September 2015 once per month. Environmental controls (water table, soil temperature and soil moisture) that effect the respiration sources were recorded. In my study I used a Li-COR 6400XT and a Los Gatos greenhouse gas analyzer (GGA). Reco was determined by chamber flux measurements with the GGA, while simultaneously CO2 respiration measurements on different vegetation compartments like roots, leaves and mosses were conducted using the Li-COR 6400XT. The difference between Reco and autotrophic respiration equals heterotrophic respiration. After the measurements, the vegetation plots were harvested and separated for all compartments (leaves, roots, mosses, soil organic matter), dried and weighed. The weighted respiration rates from all vegetation compartments sum up to

  1. A distinct seasonal pattern of the ratio of soil respiration to total ecosystem respiration in a spruce-dominated forest

    Treesearch

    E.A. Davidson; A.D. Richardson; K.E. Savage; D.Y. Hollinger

    2006-01-01

    Annual budgets and fitted temperature response curves for soil respiration and ecosystem respiration provide useful information for partitioning annual carbon budgets of ecosystems, but they may not adequately reveal seasonal variation in the ratios of these two fluxes. Soil respiration (Rs) typically contributes 30-80% of...

  2. Occupational Exposure to Respirable Dust, Respirable Crystalline Silica and Diesel Engine Exhaust Emissions in the London Tunnelling Environment.

    PubMed

    Galea, Karen S; Mair, Craig; Alexander, Carla; de Vocht, Frank; van Tongeren, Martie

    2016-03-01

    Personal 8-h shift exposure to respirable dust, diesel engine exhaust emissions (DEEE) (as respirable elemental carbon), and respirable crystalline silica of workers involved in constructing an underground metro railway tunnel was assessed. Black carbon (BC) concentrations were also assessed using a MicroAeth AE51. During sprayed concrete lining (SCL) activities in the tunnel, the geometric mean (GM) respirable dust exposure level was 0.91mg m(-3), with the highest exposure measured on a back-up sprayer (3.20mg m(-3)). The GM respirable crystalline silica concentration for SCL workers was 0.03mg m(-3), with the highest measurement also for the back-up sprayer (0.24mg m(-3)). During tunnel boring machine (TBM) activities, the GM respirable dust concentration was 0.54mg m(-3). The GM respirable elemental carbon concentration for all the TBM operators was 18 µg m(-3); with the highest concentration measured on a segment lifter. The BC concentrations were higher in the SCL environment in comparison to the TBM environment (daily GM 18-54 µg m(-3) versus 3-6 µg m(-3)). This small-scale monitoring campaign provides additional personal data on exposures experienced by underground tunnel construction workers. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  3. Clinical pulmonary function and industrial respirator wear

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Raven, P.B.; Moss, R.F.; Page, K.

    1981-12-01

    This investigation was the initial step in determining a clinical pulmonary test which could be used to evaluate workers as to their suitability to industrial respirator wear. Sixty subjects, 12 superior, 37 normal, and 11 moderately impaired with respect to lung function tests were evaluated with a battery of clinical pulmonary tests while wearing an industrial respirator. The respirator was a full-face mask (MSA-Ultravue) demand breathing type equipped with an inspiratory resistance of 85mm H/sub 2/O at 85 L/min air flow and an expiratory resistance of 25mm H/sub 2/O at 85 L/min air flow. Comparisons of these tests were mademore » between the three groups of subjects both with and without a respirator. It appears that those lung tests which measure the flow characteristics of the lung especially those that are effort dependant are more susceptible to change as a result of respirator wear. Hence, the respirator affects the person with superior lung function to a greater degree than the moderately impaired person. It was suggested that the clinical test of 15 second maximum voluntary ventilations (MVV./sub 25/) may be the test of choice for determining worker capability in wearing an industrial respirator.« less

  4. Frost Induces Respiration and Accelerates Carbon Depletion in Trees.

    PubMed

    Sperling, Or; Earles, J Mason; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A

    2015-01-01

    Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC) availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0 °C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq.) cm(-3) yr(-1) on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics.

  5. Frost Induces Respiration and Accelerates Carbon Depletion in Trees

    PubMed Central

    Sperling, Or; Earles, J. Mason; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A.

    2015-01-01

    Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC) availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0°C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq.) cm-3 yr-1 on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics. PMID:26629819

  6. 42 CFR 84.191 - Chemical cartridge respirators; required components.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Chemical cartridge respirators; required components... Chemical Cartridge Respirators § 84.191 Chemical cartridge respirators; required components. (a) Each chemical cartridge respirator described in § 84.190 shall, where its design requires, contain the following...

  7. 42 CFR 84.191 - Chemical cartridge respirators; required components.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Chemical cartridge respirators; required components... Chemical Cartridge Respirators § 84.191 Chemical cartridge respirators; required components. (a) Each chemical cartridge respirator described in § 84.190 shall, where its design requires, contain the following...

  8. 42 CFR 84.191 - Chemical cartridge respirators; required components.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Chemical cartridge respirators; required components... Chemical Cartridge Respirators § 84.191 Chemical cartridge respirators; required components. (a) Each chemical cartridge respirator described in § 84.190 shall, where its design requires, contain the following...

  9. 42 CFR 84.191 - Chemical cartridge respirators; required components.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Chemical cartridge respirators; required components... Chemical Cartridge Respirators § 84.191 Chemical cartridge respirators; required components. (a) Each chemical cartridge respirator described in § 84.190 shall, where its design requires, contain the following...

  10. 42 CFR 84.191 - Chemical cartridge respirators; required components.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Chemical cartridge respirators; required components... Chemical Cartridge Respirators § 84.191 Chemical cartridge respirators; required components. (a) Each chemical cartridge respirator described in § 84.190 shall, where its design requires, contain the following...

  11. Ammonium excretion and oxygen respiration of tropical copepods and euphausiids exposed to oxygen minimum zone conditions

    NASA Astrophysics Data System (ADS)

    Kiko, Rainer; Hauss, Helena; Buchholz, Friedrich; Melzner, Frank

    2016-04-01

    Calanoid copepods and euphausiids are key components of marine zooplankton communities worldwide. Most euphausiids and several copepod species perform diel vertical migrations (DVMs) that contribute to the export of particulate and dissolved matter to midwater depths. In vast areas of the global ocean, and in particular in the eastern tropical Atlantic and Pacific, the daytime distribution depth of many migrating organisms corresponds to the core of the oxygen minimum zone (OMZ). At depth, the animals experience reduced temperature and oxygen partial pressure (pO2) and an increased carbon dioxide partial pressure (pCO2) compared to their near-surface nighttime habitat. Although it is well known that low oxygen levels can inhibit respiratory activity, the respiration response of tropical copepods and euphausiids to relevant pCO2, pO2, and temperature conditions remains poorly parameterized. Further, the regulation of ammonium excretion at OMZ conditions is generally not well understood. It was recently estimated that DVM-mediated ammonium supply could fuel bacterial anaerobic ammonium oxidation - a major loss process for fixed nitrogen in the ocean considerably. These estimates were based on the implicit assumption that hypoxia or anoxia in combination with hypercapnia (elevated pCO2) does not result in a down-regulation of ammonium excretion. We exposed calanoid copepods from the Eastern Tropical North Atlantic (ETNA; Undinula vulgaris and Pleuromamma abdominalis) and euphausiids from the Eastern Tropical South Pacific (ETSP; Euphausia mucronata) and the ETNA (Euphausia gibboides) to different temperatures, carbon dioxide and oxygen levels to study their survival, respiration and excretion rates at these conditions. An increase in temperature by 10 °C led to an approximately 2-fold increase of the respiration and excretion rates of U. vulgaris (Q10, respiration = 1.4; Q10, NH4-excretion = 1.6), P. abdominalis (Q10, respiration = 2.0; Q10, NH4-excretion = 2.4) and

  12. Characterization of particulate-bound PAHs in rural households using different types of domestic energy in Henan Province, China.

    PubMed

    Wu, Fuyong; Liu, Xueping; Wang, Wei; Man, Yu Bon; Chan, Chuen Yu; Liu, Wenxin; Tao, Shu; Wong, Ming Hung

    2015-12-01

    The concentrations and composition of sixteen PAHs adsorbed to respirable particulate matter (PM10≤10 μm) and inhalable particulate matter (PM2.5≤2.5 μm) were determined during autumn and winter in rural households of Henan Province, China, which used four types of domestic energy [crop residues, coal, liquid petroleum gas (LPG) and electricity] for cooking and heating. The present results show that there were significantly (p<0.05) seasonal variations of particulate-bound PAHs in the rural households. The daily mean concentrations of particulate-bound PAHs in the kitchens, sitting rooms and outdoors were apparently higher in winter than those in autumn, except those in the kitchens using coal. The present study also shows that there were obvious variations of particulate-bound PAHs among the four types of domestic energy used in the rural households. The households using LPG for cooking can, at least in some circumstances, have higher concentrations of PAHs in the kitchens than using crop residues or electricity. In addition, using coal in the sitting rooms seemed to result in apparently higher concentrations of particulate-bound PAHs than using the other three types of domestic energy during winter. The most severe contamination occurred in the kitchens using LPG in winter, where the daily mean concentrations of PM2.5-bound PAHs were up to 762.5±931.2 ng m(-3), indicating that there was serious health risk of inhalation exposure to PAHs in the rural households of Henan Province. Rural residents' exposure to PM2.5-bound PAHs in kitchens would be roughly reduced by 69.8% and 85.5% via replacing coal or crop residues with electricity in autumn. The pilot research would provide important supplementary information to the indoor air pollution studies in rural area. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Organic speciation of size-segregated atmospheric particulate matter

    NASA Astrophysics Data System (ADS)

    Tremblay, Raphael

    Particle size and composition are key factors controlling the impacts of particulate matter (PM) on human health and the environment. A comprehensive method to characterize size-segregated PM organic content was developed, and evaluated during two field campaigns. Size-segregated particles were collected using a cascade impactor (Micro-Orifice Uniform Deposit Impactor) and a PM2.5 large volume sampler. A series of alkanes and polycyclic aromatic hydrocarbons (PAHs) were solvent extracted and quantified using a gas chromatograph coupled with a mass spectrometer (GC/MS). Large volume injections were performed using a programmable temperature vaporization (PTV) inlet to lower detection limits. The developed analysis method was evaluated during the 2001 and 2002 Intercomparison Exercise Program on Organic Contaminants in PM2.5 Air Particulate Matter led by the US National Institute of Standards and Technology (NIST). Ambient samples were collected in May 2002 as part of the Tampa Bay Regional Atmospheric Chemistry Experiment (BRACE) in Florida, USA and in July and August 2004 as part of the New England Air Quality Study - Intercontinental Transport and Chemical Transformation (NEAQS - ITCT) in New Hampshire, USA. Morphology of the collected particles was studied using scanning electron microscopy (SEM). Smaller particles (one micrometer or less) appeared to consist of solid cores surrounded by a liquid layer which is consistent with combustion particles and also possibly with particles formed and/or coated by secondary material like sulfate, nitrate and secondary organic aerosols. Source apportionment studies demonstrated the importance of stationary sources on the organic particulate matter observed at these two rural sites. Coal burning and biomass burning were found to be responsible for a large part of the observed PAHs during the field campaigns. Most of the measured PAHs were concentrated in particles smaller than one micrometer and linked to combustion sources

  14. Cross-correlation of heartbeat and respiration rhythms

    NASA Astrophysics Data System (ADS)

    Capurro, A.; Malta, C. P.; Diambra, L.; Contreras, P.; Migliaro, E. R.

    2005-10-01

    The cross-correlation function between respiration and heart beat interval series shows that during metronomized breathing the heart beat follows the respiration more closely than during spontaneous breathing. We reproduced the heart beat interval modulations during metronomized breathing using a biophysical model of the sinoatrial node excited by an input signal formed by the recorded respiration. In the case of spontaneous breathing, a good agreement with the experimental data was obtained only by using an input signal formed by the sum of the recorded respiration and a realization of correlated noise. Metronomized breathing refers to the situation where a subject breathes following the rhythm of a metronome.

  15. BOREAS TE-5 Soil Respiration Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Ehleriinger, Jim; Brooks, J. Renee; Flanagan, Larry

    2000-01-01

    The BOREAS TE-5 team collected measurements in the NSA and SSA on gas exchange, gas composition, and tree growth. Soil respiration data were collected from 26-May-94 to 07-Sep-94 in the BOREAS NSA and SSA to compare the soil respiration rates in different forest sites using a LI-COR 6200 soil respiration chamber (model 6299). The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distrobuted Activity Archive Center (DAAC).

  16. 42 CFR 84.190 - Chemical cartridge respirators: description.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Chemical cartridge respirators: description. 84.190... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.190 Chemical cartridge respirators: description. (a) Chemical cartridge...

  17. 42 CFR 84.190 - Chemical cartridge respirators: description.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Chemical cartridge respirators: description. 84.190... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.190 Chemical cartridge respirators: description. (a) Chemical cartridge...

  18. 42 CFR 84.190 - Chemical cartridge respirators: description.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Chemical cartridge respirators: description. 84.190... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.190 Chemical cartridge respirators: description. (a) Chemical cartridge...

  19. 42 CFR 84.190 - Chemical cartridge respirators: description.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Chemical cartridge respirators: description. 84.190... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.190 Chemical cartridge respirators: description. (a) Chemical cartridge...

  20. 42 CFR 84.190 - Chemical cartridge respirators: description.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Chemical cartridge respirators: description. 84.190... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.190 Chemical cartridge respirators: description. (a) Chemical cartridge...

  1. RESPIRATION AND INTENSITY DEPENDENCE OF PHOTOSYNTHESIS IN CHLORELLA

    PubMed Central

    Brackett, Frederick S.; Olson, Rodney A.; Crickard, Robert G.

    1953-01-01

    1. Respiration changes as a result of illumination. 2. In the absence of glucose or other supply of substrate, respiration decays in the dark showing at least two types—a fast decay in a few minutes and a slow decay lasting hours. 3. Respiratory response to illumination is delayed. 4. Intermittent illumination (in the absence of glucose, etc.) produces a periodic variation in respiration with a delay or phase lag. 5. Periodic variation of respiration may produce a higher average value in the dark than in the light due to the lag and depending upon the period of intermittent illumination. 6. Based upon average respiration values our data confirm the Kok effect. 7. Interpolated values of respiration, however, result in photosynthetic rates which are linearly dependent upon intensity of illumination. 8. Thus the quantum efficiency is found to be independent of intensity, over the wide range of intensities investigated. PMID:13035068

  2. What controls respiration rate in stored sugarbeet roots

    USDA-ARS?s Scientific Manuscript database

    Although respiration is estimated to be responsible for 60 to 80% of the sucrose lost during storage, the mechanisms by which sugarbeet roots regulate their respiration rate are unknown. In plants, respiration rate is regulated by (1) available respiratory capacity, (2) cellular energy status, (3) ...

  3. An Evaluation of an Aftermarket Local Exhaust Ventilation Device for Suppressing Respirable Dust and Respirable Crystalline Silica Dust from Powered Saws

    PubMed Central

    Garcia, Alberto; Jones, Erica; Echt, Alan S.; Hall, Ronald M.

    2015-01-01

    The objective of this study was to quantify the respirable dust and respirable silica exposures of roofing workers using an electric powered circular saw with an aftermarket local exhaust ventilation attachment to cut concrete roofing tiles. The study was conducted to determine whether the local exhaust ventilation attachment was able to control respirable dust and respirable silica exposure below occupational exposure limits. Time-integrated filter samples and direct reading respirable dust concentrations were evaluated. The local exhaust ventilation consisted of a shroud attached to the cutting plane of the saw; the shroud was then connected to a small electric axial fan, which is intended to collect dust at the point of generation. All sampling was conducted with the control in use. Roofers are defined as those individuals who solely lay tiles. Cutters/roofers are defined as those workers who operate the powered saw to cut tiles and also lay tiles. Respirable dust from this evaluation ranged from 0.13 to 6.59 milligrams per cubic meter (mg/m3) with a geometric mean of 0.38 mg/m3 for roofers and from 0.45 to 3.82 mg/m3 with a geometric mean of 1.84 mg/m3 for cutters/roofers. Cutters/roofers usually handle areas close to crevices, edges, or tips of the roof whereas roofers handle areas where complete tiles can be placed. The respirable dust exposures for all cutters/roofers indicated concentrations exceeding the Occupational Safety and Health Administration’s (OSHA) permissible exposure limit (PEL) for respirable dust containing silica; it was also exceeded for some of the roofers. The respirable silica concentrations ranged from 0.04 to 0.15 mg/m3 with an average of 0.09 mg/m3 for roofers, and from 0.13 to 1.21 mg/m3 with an average of 0.48 mg/m3 for cutters/roofers. As with respirable dust, the respirable silica exposures to cutters/roofers were higher than the exposures for roofers. PMID:25148513

  4. An evaluation of an aftermarket local exhaust ventilation device for suppressing respirable dust and respirable crystalline silica dust from powered saws.

    PubMed

    Garcia, Alberto; Jones, Erica; Echt, Alan S; Hall, Ronald M

    2014-01-01

    The objective of this study was to quantify the respirable dust and respirable silica exposures of roofing workers using an electric-powered circular saw with an aftermarket local exhaust ventilation attachment to cut concrete roofing tiles. The study was conducted to determine whether the local exhaust ventilation attachment was able to control respirable dust and respirable silica exposure below occupational exposure limits (OELs). Time-integrated filter samples and direct reading respirable dust concentrations were evaluated. The local exhaust ventilation consisted of a shroud attached to the cutting plane of the saw; the shroud was then connected to a small electric axial fan, which is intended to collect dust at the point of generation. All sampling was conducted with the control in use. Roofers are defined as those individuals who only lay tiles. Cutters/roofers are defined as those workers who operate the powered saw to cut tiles and also lay tiles. Respirable dust from this evaluation ranged from 0.13 to 6.59 milligrams per cubic meter (mg/m(3)) with a geometric mean of 0.38 mg/m(3) for roofers and from 0.45 to 3.82 mg/m(3) with a geometric mean of 1.84 mg/m(3) for cutters/roofers. Cutters/roofers usually handle areas close to crevices, edges, or tips of the roof whereas roofers handle areas where complete tiles can be placed. The respirable dust exposures for all cutters/roofers indicated concentrations exceeding the Occupational Safety and Health Administration's (OSHA) permissible exposure limit (PEL) for respirable dust containing silica; it was also exceeded for some of the roofers. The respirable silica concentrations ranged from 0.04 to 0.15 mg/m(3) with a geometric mean of 0.09 mg/m(3) for roofers, and from 0.13 to 1.21 mg/m(3) with a geometric mean of 0.48 mg/m(3) for cutters/roofers. As with respirable dust, the respirable silica exposures for cutters/roofers were higher than the exposures for roofers.

  5. Improving respiration measurements with gas exchange analyzers.

    PubMed

    Montero, R; Ribas-Carbó, M; Del Saz, N F; El Aou-Ouad, H; Berry, J A; Flexas, J; Bota, J

    2016-12-01

    Dark respiration measurements with open-flow gas exchange analyzers are often questioned for their low accuracy as their low values often reach the precision limit of the instrument. Respiration was measured in five species, two hypostomatous (Vitis Vinifera L. and Acanthus mollis) and three amphistomatous, one with similar amount of stomata in both sides (Eucalyptus citriodora) and two with different stomata density (Brassica oleracea and Vicia faba). CO 2 differential (ΔCO 2 ) increased two-fold with no change in apparent R d , when the two leaves with higher stomatal density faced outside. These results showed a clear effect of the position of stomata on ΔCO 2 . Therefore, it can be concluded that leaf position is important to guarantee the improvement of respiration measurements increasing ΔCO 2 without affecting the respiration results by leaf or mass units. This method will help to increase the accuracy of leaf respiration measurements using gas exchange analyzers. Copyright © 2016 Elsevier GmbH. All rights reserved.

  6. 42 CFR 84.125 - Particulate tests; canisters containing particulate filters; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... filters; minimum requirements. 84.125 Section 84.125 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF... RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.125 Particulate tests; canisters containing particulate filters; minimum requirements. Gas mask canisters containing filters for protection against particulates (e.g...

  7. 42 CFR 84.125 - Particulate tests; canisters containing particulate filters; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... filters; minimum requirements. 84.125 Section 84.125 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF... RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.125 Particulate tests; canisters containing particulate filters; minimum requirements. Gas mask canisters containing filters for protection against particulates (e.g...

  8. 42 CFR 84.125 - Particulate tests; canisters containing particulate filters; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... filters; minimum requirements. 84.125 Section 84.125 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF... RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.125 Particulate tests; canisters containing particulate filters; minimum requirements. Gas mask canisters containing filters for protection against particulates (e.g...

  9. 42 CFR 84.125 - Particulate tests; canisters containing particulate filters; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... filters; minimum requirements. 84.125 Section 84.125 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF... RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.125 Particulate tests; canisters containing particulate filters; minimum requirements. Gas mask canisters containing filters for protection against particulates (e.g...

  10. 42 CFR 84.125 - Particulate tests; canisters containing particulate filters; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... filters; minimum requirements. 84.125 Section 84.125 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF... RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84.125 Particulate tests; canisters containing particulate filters; minimum requirements. Gas mask canisters containing filters for protection against particulates (e.g...

  11. Quantifying soil respiration at landscape scales. Chapter 11

    Treesearch

    John B. Bradford; Michael G. Ryan

    2008-01-01

    Soil CO2, efflux, or soil respiration, represents a substantial component of carbon cycling in terrestrial ecosystems. Consequently, quantifying soil respiration over large areas and long time periods is an increasingly important goal. However, soil respiration rates vary dramatically in space and time in response to both environmental conditions...

  12. Photosynthesis and Respiration in a Jar.

    ERIC Educational Resources Information Center

    Buttner, Joseph K.

    2000-01-01

    Describes an activity that reduces the biosphere to a water-filled jar to simulate the relationship between cellular respiration, photosynthesis, and energy. Allows students in high school biology and related courses to explore quantitatively cellular respiration and photosynthesis in almost any laboratory setting. (ASK)

  13. Antibiotic efficacy is linked to bacterial cellular respiration

    PubMed Central

    Lobritz, Michael A.; Belenky, Peter; Porter, Caroline B. M.; Gutierrez, Arnaud; Yang, Jason H.; Schwarz, Eric G.; Dwyer, Daniel J.; Khalil, Ahmad S.; Collins, James J.

    2015-01-01

    Bacteriostatic and bactericidal antibiotic treatments result in two fundamentally different phenotypic outcomes—the inhibition of bacterial growth or, alternatively, cell death. Most antibiotics inhibit processes that are major consumers of cellular energy output, suggesting that antibiotic treatment may have important downstream consequences on bacterial metabolism. We hypothesized that the specific metabolic effects of bacteriostatic and bactericidal antibiotics contribute to their overall efficacy. We leveraged the opposing phenotypes of bacteriostatic and bactericidal drugs in combination to investigate their activity. Growth inhibition from bacteriostatic antibiotics was associated with suppressed cellular respiration whereas cell death from most bactericidal antibiotics was associated with accelerated respiration. In combination, suppression of cellular respiration by the bacteriostatic antibiotic was the dominant effect, blocking bactericidal killing. Global metabolic profiling of bacteriostatic antibiotic treatment revealed that accumulation of metabolites involved in specific drug target activity was linked to the buildup of energy metabolites that feed the electron transport chain. Inhibition of cellular respiration by knockout of the cytochrome oxidases was sufficient to attenuate bactericidal lethality whereas acceleration of basal respiration by genetically uncoupling ATP synthesis from electron transport resulted in potentiation of the killing effect of bactericidal antibiotics. This work identifies a link between antibiotic-induced cellular respiration and bactericidal lethality and demonstrates that bactericidal activity can be arrested by attenuated respiration and potentiated by accelerated respiration. Our data collectively show that antibiotics perturb the metabolic state of bacteria and that the metabolic state of bacteria impacts antibiotic efficacy. PMID:26100898

  14. Nutrients and temperature additively increase stream microbial respiration

    Treesearch

    David W. P. Manning; Amy D. Rosemond; Vladislav Gulis; Jonathan P. Benstead; John S. Kominoski

    2017-01-01

    Rising temperatures and nutrient enrichment are co‐occurring global‐change drivers that stimulate microbial respiration of detrital carbon, but nutrient effects on the temperature dependence of respiration in aquatic ecosystems remain uncertain. We measured respiration rates associated with leaf litter, wood, and fine benthic organic matter (FBOM) across...

  15. Single-Frequency Ultrasound-Based Respiration Rate Estimation with Smartphones.

    PubMed

    Ge, Linfei; Zhang, Jin; Wei, Jing

    2018-01-01

    Respiration monitoring is helpful in disease prevention and diagnosis. Traditional respiration monitoring requires users to wear devices on their bodies, which is inconvenient for them. In this paper, we aim to design a noncontact respiration rate detection system utilizing off-the-shelf smartphones. We utilize the single-frequency ultrasound as the media to detect the respiration activity. By analyzing the ultrasound signals received by the built-in microphone sensor in a smartphone, our system can derive the respiration rate of the user. The advantage of our method is that the transmitted signal is easy to generate and the signal analysis is simple, which has lower power consumption and thus is suitable for long-term monitoring in daily life. The experimental result shows that our system can achieve accurate respiration rate estimation under various scenarios.

  16. 42 CFR 84.253 - Chemical-cartridge respirators; requirements and tests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Chemical-cartridge respirators; requirements and... DEVICES Special Use Respirators § 84.253 Chemical-cartridge respirators; requirements and tests. (a... for chemical-cartridge respirators prescribed in Subpart L of this part are applicable to replaceable...

  17. 42 CFR 84.253 - Chemical-cartridge respirators; requirements and tests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Chemical-cartridge respirators; requirements and... DEVICES Special Use Respirators § 84.253 Chemical-cartridge respirators; requirements and tests. (a... for chemical-cartridge respirators prescribed in Subpart L of this part are applicable to replaceable...

  18. Global spatiotemporal distribution of soil respiration modeled using a global database

    NASA Astrophysics Data System (ADS)

    Hashimoto, S.; Carvalhais, N.; Ito, A.; Migliavacca, M.; Nishina, K.; Reichstein, M.

    2015-07-01

    The flux of carbon dioxide from the soil to the atmosphere (soil respiration) is one of the major fluxes in the global carbon cycle. At present, the accumulated field observation data cover a wide range of geographical locations and climate conditions. However, there are still large uncertainties in the magnitude and spatiotemporal variation of global soil respiration. Using a global soil respiration data set, we developed a climate-driven model of soil respiration by modifying and updating Raich's model, and the global spatiotemporal distribution of soil respiration was examined using this model. The model was applied at a spatial resolution of 0.5°and a monthly time step. Soil respiration was divided into the heterotrophic and autotrophic components of respiration using an empirical model. The estimated mean annual global soil respiration was 91 Pg C yr-1 (between 1965 and 2012; Monte Carlo 95 % confidence interval: 87-95 Pg C yr-1) and increased at the rate of 0.09 Pg C yr-2. The contribution of soil respiration from boreal regions to the total increase in global soil respiration was on the same order of magnitude as that of tropical and temperate regions, despite a lower absolute magnitude of soil respiration in boreal regions. The estimated annual global heterotrophic respiration and global autotrophic respiration were 51 and 40 Pg C yr-1, respectively. The global soil respiration responded to the increase in air temperature at the rate of 3.3 Pg C yr-1 °C-1, and Q10 = 1.4. Our study scaled up observed soil respiration values from field measurements to estimate global soil respiration and provide a data-oriented estimate of global soil respiration. The estimates are based on a semi-empirical model parameterized with over one thousand data points. Our analysis indicates that the climate controls on soil respiration may translate into an increasing trend in global soil respiration and our analysis emphasizes the relevance of the soil carbon flux from soil to

  19. Plant growth and respiration re-visited: maintenance respiration defined – it is an emergent property of, not a separate process within, the system – and why the respiration : photosynthesis ratio is conservative

    PubMed Central

    Thornley, John H. M.

    2011-01-01

    Background and Aims Plant growth and respiration still has unresolved issues, examined here using a model. The aims of this work are to compare the model's predictions with McCree's observation-based respiration equation which led to the ‘growth respiration/maintenance respiration paradigm’ (GMRP) – this is required to give the model credibility; to clarify the nature of maintenance respiration (MR) using a model which does not represent MR explicitly; and to examine algebraic and numerical predictions for the respiration:photosynthesis ratio. Methods A two-state variable growth model is constructed, with structure and substrate, applicable on plant to ecosystem scales. Four processes are represented: photosynthesis, growth with growth respiration (GR), senescence giving a flux towards litter, and a recycling of some of this flux. There are four significant parameters: growth efficiency, rate constants for substrate utilization and structure senescence, and fraction of structure returned to the substrate pool. Key Results The model can simulate McCree's data on respiration, providing an alternative interpretation to the GMRP. The model's parameters are related to parameters used in this paradigm. MR is defined and calculated in terms of the model's parameters in two ways: first during exponential growth at zero growth rate; and secondly at equilibrium. The approaches concur. The equilibrium respiration:photosynthesis ratio has the value of 0·4, depending only on growth efficiency and recycling fraction. Conclusions McCree's equation is an approximation that the model can describe; it is mistaken to interpret his second coefficient as a maintenance requirement. An MR rate is defined and extracted algebraically from the model. MR as a specific process is not required and may be replaced with an approach from which an MR rate emerges. The model suggests that the respiration:photosynthesis ratio is conservative because it depends on two parameters only whose

  20. Thawing permafrost increases old soil and autotrophic respiration in tundra: partitioning ecosystem respiration using δ(13) C and ∆(14) C.

    PubMed

    Hicks Pries, Caitlin E; Schuur, Edward A G; Crummer, Kathryn G

    2013-02-01

    Ecosystem respiration (Reco ) is one of the largest terrestrial carbon (C) fluxes. The effect of climate change on Reco depends on the responses of its autotrophic and heterotrophic components. How autotrophic and heterotrophic respiration sources respond to climate change is especially important in ecosystems underlain by permafrost. Permafrost ecosystems contain vast stores of soil C (1672 Pg) and are located in northern latitudes where climate change is accelerated. Warming will cause a positive feedback to climate change if heterotrophic respiration increases without corresponding increases in primary production. We quantified the response of autotrophic and heterotrophic respiration to permafrost thaw across the 2008 and 2009 growing seasons. We partitioned Reco using Δ(14) C and δ(13) C into four sources-two autotrophic (above - and belowground plant structures) and two heterotrophic (young and old soil). We sampled the Δ(14) C and δ(13) C of sources using incubations and the Δ(14) C and δ(13) C of Reco using field measurements. We then used a Bayesian mixing model to solve for the most likely contributions of each source to Reco . Autotrophic respiration ranged from 40 to 70% of Reco and was greatest at the height of the growing season. Old soil heterotrophic respiration ranged from 6 to 18% of Reco and was greatest where permafrost thaw was deepest. Overall, growing season fluxes of autotrophic and old soil heterotrophic respiration increased as permafrost thaw deepened. Areas with greater thaw also had the greatest primary production. Warming in permafrost ecosystems therefore leads to increased plant and old soil respiration that is initially compensated by increased net primary productivity. However, barring large shifts in plant community composition, future increases in old soil respiration will likely outpace productivity, resulting in a positive feedback to climate change. © 2012 Blackwell Publishing Ltd.

  1. [The development of a respiration and temperature monitor].

    PubMed

    Du, X; Wu, B; Liu, Y; He, Q; Xiao, J

    2001-12-01

    This paper introduces the design of a monitoring system to measure the respiration and temperature of a body with an 8Xc196 single-chip microcomputer. This system can measure and display the respiration wave, respiration frequency and the body temperature in real-time with a liquid crystal display (LCD) and give an alarm when the parameters are beyond the normal scope. In addition, this device can provide a 24 hours trend graph of the respiration frequency and the body temperature parameters measured. Data can also be exchanged through serial communication interfaces (RS232) between the PC and the monitor.

  2. Enhancement in in vitro anti-angiogenesis activity and cytotoxicity in lung cancer cell by pectin-PVP based curcumin particulates.

    PubMed

    Gaikwad, Dinanath; Shewale, Rajnita; Patil, Vinit; Mali, Dipak; Gaikwad, Uday; Jadhav, Namdeo

    2017-11-01

    The aim of this work was to prepare pectin-poly (vinyl pyrrolidone) [PVP] based curcumin particulates to enhance the anticancer potential of curcumin, solubility and allow its localized controlled release. Pectin-PVP based curcumin particulates (PECTIN-PVP CUR) were prepared by spray drying technique in different ratios and were evaluated for surface morphology, micromeritics, flowability, particle size, drug content, in vitro dissolution, inhalable fraction, anti-angiogenesis/angiolysis and cytotoxicity. Results of micromeritic properties, Carr's index, Hausner's ratio and angle of repose were satisfactory. The batch CP3 was considered as optimum, due to excellent flowability, acceptable aggregation and enhanced solubility. The particle size and size distribution data of selected batch CP3 showed 90% of curcumin particulates having size less than 2.74μm, which may deposit to lungs. Twin Impinger studies showed that 29% of respirable fraction was generated, which could be directly delivered to lungs. The in vitro dissolution data showed many fold increase in dissolution rate. Angiolytic activity and MTT assay of PECTIN-PVP CUR have demonstrated enhancement in the anti-tumor potential, compared to curcumin alone. Altogether, PECTIN-PVP CUR were found suitable for local delivery and enhance its anticancer potential of curcumin. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Single-Frequency Ultrasound-Based Respiration Rate Estimation with Smartphones

    PubMed Central

    Wei, Jing

    2018-01-01

    Respiration monitoring is helpful in disease prevention and diagnosis. Traditional respiration monitoring requires users to wear devices on their bodies, which is inconvenient for them. In this paper, we aim to design a noncontact respiration rate detection system utilizing off-the-shelf smartphones. We utilize the single-frequency ultrasound as the media to detect the respiration activity. By analyzing the ultrasound signals received by the built-in microphone sensor in a smartphone, our system can derive the respiration rate of the user. The advantage of our method is that the transmitted signal is easy to generate and the signal analysis is simple, which has lower power consumption and thus is suitable for long-term monitoring in daily life. The experimental result shows that our system can achieve accurate respiration rate estimation under various scenarios. PMID:29853985

  4. Velocity-amplified microbial respiration rates in the lower Amazon River: Amazon River respiration

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ward, Nicholas D.; Sawakuchi, Henrique O.; Neu, Vania

    Most measurements of respiration rates in large tropical rivers do not account for the influence of river flow conditions on microbial activity. We developed a ship-board spinning incubation system for measuring O2 drawdown under different rotation velocities and deployed the system along the lower Amazon River during four hydrologic periods. Average respiration rates in incubation chambers rotated at 0.22 and 0.66 m s-1 were 1.4 and 2.4 times higher than stationary chambers, respectively. On average, depth-integrated respiration rates in chambers spun at 0.22 and 0.66 m s-1 accounted for 64 ± 22% and 104 ± 36% of CO2 outgassing rates,more » respectively, in mainstem sites. Continuous measurements of in situ pCO2 were also made along with cross-channel profiles of river velocity. A positive correlation between river velocity and pCO2 was observed along the lower river (r2=0.67-0.96) and throughout a tidal cycle.« less

  5. Respiration from the organ level to the stand

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sprugel, D.G.; Ryan, M.G.; Brooks, J.R.

    1995-07-01

    The status of efforts to estimate respiration of conifers varies sharply from one tissue to another. There have been numerous measurements of foliage respiration in conifers, but relatively few measurements of within-stand variation in reference to parameters that might be used for scaling. However, a number of logical models for scaling have been proposed (e.g., light, age, or N) and general directions for future research seem well established. There are far fewer measurements of woody-tissue respiration that might be useful for scaling, but some consensus seems to have developed that the use of sapwood biomass and growth rates as indicesmore » may provide the key to scaling woody-tissue respiration up to the stand level. Root respiration is still bogged down by a plurality of methods, each of which seems to have some serious disadvantages, so that even the nature of within-stand variation is poorly known. Successful and believable scaling of root respiration from tissue-specific measurements to the stand level seems to be far in the future. Finally, proxy measurements such as litterfall and N concentration can and have been used to estimate respiration for whole stands without measuring tissue-specific rates at all, but all of these techniques require assumptions that need further testing before they will be generally accepted.« less

  6. Respirable dust measured downwind during rock dust application.

    PubMed

    Harris, M L; Organiscak, J; Klima, S; Perera, I E

    2017-05-01

    The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH's Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners' exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device.

  7. Kuwaiti oil fires—Particulate monitoring

    NASA Astrophysics Data System (ADS)

    Husain, Tahir; Amin, Mohamed B.

    The total suspended particulate (TSP) matters using a high-volume sampler and inhalable particulate matters using PM-10 samplers were collected at various locations in the Eastern Province of Saudi Arabia during and after the Kuwaiti oil fires. The collected samples were analysed for toxic metals and oil hydrocarbon concentrations including some carcinogenic organic compounds in addition to gravimetric analysis. The concentration values of particulate matters were determined on a daily basis at Dhahran. Abqaiq, Rahima, Tanajib and Jubail locations. The analyses of the filters show a high concentration of the inhalable particulate at various locations, especially when north or northwest winds were blowing. It was found that the inhalable particulate concentration exceeded the Meteorology and Environmental Protection Administration (MEPA) permissible limit of 340 μg m- 3 at most of these locations during May-October 1991. A trend between the total suspended particulate and inhalable particulate measured concurrently at the same locations was observed and a regression equation was developed to correlate PM-10 data with the total suspended particulate data.

  8. Constraining Night Time Ecosystem Respiration by Inverse Approaches

    NASA Astrophysics Data System (ADS)

    Juang, J.; Stoy, P. C.; Siqueira, M. B.; Katul, G. G.

    2004-12-01

    Estimating nighttime ecosystem respiration remains a key challenge in quantifying ecosystem carbon budgets. Currently, nighttime eddy-covariance (EC) flux measurements are plagued by uncertainties often attributed to poor mixing within the canopy volume, non-turbulent transport of CO2 into and out of the canopy, and non-stationarity and intermittency. Here, we explore the use of second-order closure models to estimate nighttime ecosystem respiration by mathematically linking sources of CO2 to mean concentration profiles via the continuity and the CO2 flux budget equation modified to include thermal stratification. By forcing this model to match, in a root-mean squared sense, the nighttime measured mean CO2 concentration profiles within the canopy the above ground CO2 production and forest floor respiration can be estimated via multi-dimensional optimization techniques. We show that in a maturing pine and a mature hardwood forest, these optimized CO2 sources are (1) consistently larger than the eddy covariance flux measurements above the canopy, and (2) agree well with chamber-based measurements. We also show that by linking the optimized nighttime ecosystem respiration to temperature measurements, the estimated annual ecosystem respiration from this approach agrees well with biometric estimates, at least when compared to eddy-covariance methods conditioned on a friction velocity threshold. The difference between the annual ecosystem respiration obtained by this optimization method and the friction-velocity thresholded night-time EC fluxes can be as large as 700 g C m-2 (in 2003) for the maturing pine forest, which is about 40% of the ecosystem respiration. For 2001 and 2002, the annual ecosystem respiration differences between the EC-based and the proposed approach were on the order of 300 to 400 g C m-2.

  9. Thermal adaptation of heterotrophic soil respiration in laboratory microcosms.

    Treesearch

    Mark A. Bradford; Brian W. Watts; Christian A. Davies

    2010-01-01

    Respiration of heterotrophic microorganisms decomposing soil organic carbon releases carbon dioxide from soils to the atmosphere. In the short term, soil microbial respiration is strongly dependent on temperature. In the long term, the response of heterotrophic soil respiration to temperature is uncertain. However, following established evolutionary tradeoffs, mass-...

  10. Respirators: Air Purifying, Self-Study, Course 40723

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chochoms, Michael

    Respirators: Air Purifying Self-Study (COURSE 40723) is designed for Los Alamos National Laboratory (LANL) workers, support services subcontractors, and other LANL subcontractors who work under the LANL Respiratory Protection Program (RPP). This course also meets the air-purifying respirators (APRs) retraining requirement.

  11. EPA Extends Comment Period for Draft Label Revisions on Respirators

    EPA Pesticide Factsheets

    Extending Comment Period for Draft Label Revisions on Respirators, Bring the respirator descriptions on pesticide labels into conformance with the current National Institute for Occupational Safety and Health (NIOSH) respirator language

  12. Down-regulation of respiration in pear fruit depends on temperature.

    PubMed

    Ho, Quang Tri; Hertog, Maarten L A T M; Verboven, Pieter; Ambaw, Alemayehu; Rogge, Seppe; Verlinden, Bert E; Nicolaï, Bart M

    2018-04-09

    The respiration rate of plant tissues decreases when the amount of available O2 is reduced. There is, however, a debate on whether the respiration rate is controlled either by diffusion limitation of oxygen or through regulatory processes at the level of the transcriptome. We used experimental and modelling approaches to demonstrate that both diffusion limitation and metabolic regulation affect the response of respiration of bulky plant organs such as fruit to reduced O2 levels in the surrounding atmosphere. Diffusion limitation greatly affects fruit respiration at high temperature, but at low temperature respiration is reduced through a regulatory process, presumably a response to a signal generated by a plant oxygen sensor. The response of respiration to O2 is time dependent and is highly sensitive, particularly at low O2 levels in the surrounding atmosphere. Down-regulation of the respiration at low temperatures may save internal O2 and relieve hypoxic conditions in the fruit.

  13. 20 CFR 410.462 - Presumption relating to respirable disease.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Presumption relating to respirable disease... Pneumoconiosis § 410.462 Presumption relating to respirable disease. (a) Even though the existence of... was employed for 10 years or more in the Nation's coal mines and died from a respirable disease, it...

  14. 20 CFR 410.462 - Presumption relating to respirable disease.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Presumption relating to respirable disease... Pneumoconiosis § 410.462 Presumption relating to respirable disease. (a) Even though the existence of... was employed for 10 years or more in the Nation's coal mines and died from a respirable disease, it...

  15. Shrubs stimulate heterotrophic respiration in arctic soils

    NASA Astrophysics Data System (ADS)

    Phillips, C. A.; Wurzburger, N.

    2016-12-01

    The response of arctic ecosystems to global change will have critical effects on future climate. Climate warming has already triggered the expansion of shrubs across tundra, raising questions about how shrubs will affect ecosystem carbon balance. Shrub litter quality and mycorrhizal symbionts may accelerate the activity of soil microorganisms that facilitate the release of large stores of soil carbon. We investigated how shrubs affect the activity of soil microorganisms by creating soil mesocosms from areas with and without shrub species as dominants of the plant community in arctic Alaska. We hypothesized that relative to their non-shrub counterparts, heterotrophic respiration of shrub soils would: (1) be greater, (2) demonstrate greater response to additions of shrub litter, and (3) be less nutrient limited. We created mesocosms with root-free soils at constant moisture and temperature, and quantified basal heterotrophic soil respiration rates, and the response of respiration to litter and nutrient inputs in a series of laboratory experiments inputs. (1) We found that the presence of shrubs generally produced higher rates of basal soil respiration in both horizons, suggesting that shrubs stimulate microbial activity. (2) Litter addition increased respiration across both horizons with no differences in response between shrub and non-shrub soils. (3) N additions did not increase heterotrophic respiration, but P and N+P additions induced a short respiratory pulse in all soils, suggesting mild P limitation. Collectively, these findings provide evidence that shrubs stimulate heterotrophic microbial activity to enhance carbon loss, but generate new questions about the mechanisms driving these patterns.

  16. Respirable particles and carcinogens in the air of delaware hospitality venues before and after a smoking ban.

    PubMed

    Repace, James

    2004-09-01

    How do the concentrations of indoor air pollutants known to increase risk of respiratory disease, cancer, heart disease, and stroke change after a smoke-free workplace law? Real-time measurements were made of respirable particle (RSP) air pollution and particulate polycyclic aromatic hydrocarbons (PPAH), in a casino, six bars, and a pool hall before and after a smoking ban. Secondhand smoke contributed 90% to 95% of the RSP air pollution during smoking, and 85% to 95% of the carcinogenic PPAH, greatly exceeding levels of these contaminants encountered on major truck highways and polluted city streets. This air-quality survey demonstrates conclusively that the health of hospitality workers and patrons is endangered by tobacco smoke pollution. Smoke-free workplace laws eliminate that hazard and provide health protection impossible to achieve through ventilation or air cleaning.

  17. Watershed-Scale Heterogeneity of the Biophysical Controls on Soil Respiration

    NASA Astrophysics Data System (ADS)

    Riveros, D. A.; Pacific, V. J.; McGlynn, B. L.; Welsch, D. L.; Epstein, H. E.; Muth, D. J.; Marshall, L.; Wraith, J.

    2006-12-01

    Large gaps exist in our understanding of the variability of soil respiration response to changing hydrologic conditions across spatial and temporal scales. Determining the linkages between the hydrologic cycle and the biophysical controls of soil respiration from the local point, to the plot, to the watershed scale is critical to understanding the dynamics of net ecosystem CO2 exchange (NEE). To study the biophysical controls of soil respiration, we measured soil CO2 concentration, soil CO2 flux, dissolved CO2 in stream water, soil moisture, soil temperature, groundwater dynamics, and precipitation at 20-minute intervals throughout the growing season at 4 sites and at weekly intervals at 62 sites covering the range of topographic position, slope, aspect, land cover, and upslope accumulated area conditions in a 555-ha subalpine watershed in central Montana. Our goal was to quantify watershed-scale heterogeneity in soil CO2 concentrations and surface efflux and gain understanding of the biophysical controls on soil respiration. We seek to improve our ability to evaluate and predict soil respiration responses to a dynamic hydrologic cycle across multiple temporal and spatial scales. We found that time lags between biophysical controls and soil respiration can occur from hourly to daily scales. The sensitivity of soil respiration to changes in environmental conditions is controlled by the antecedent soil moisture and by topographic position. At the watershed scale, significant differences in soil respiration exist between upland (dry) and lowland (wet) sites. However, differences in the magnitude and timing of soil respiration also exist within upland settings due to heterogeneity in soil temperature, soil moisture, and soil organic matter. Finally, we used a process-based model to simulate respiration at different times of the year across spatial locations. Our simulations highlight the importance of autotrophic and heterotrophic respiration (production) over

  18. Effects of simulated warming on soil respiration to XiaoPo lake

    NASA Astrophysics Data System (ADS)

    Zhao, Shuangkai; Chen, Kelong; Wu, Chengyong; Mao, Yahui

    2018-02-01

    The main flux of carbon cycling in terrestrial and atmospheric ecosystems is soil respiration, and soil respiration is one of the main ways of soil carbon output. This is of great significance to explore the dynamic changes of soil respiration rate and its effect on temperature rise, and the correlation between environmental factors and soil respiration. In this study, we used the open soil carbon flux measurement system (LI-8100, LI-COR, NE) in the experimental area of the XiaoPo Lake wetland in the Qinghai Lake Basin, and the Kobresia (Rs) were measured, and the soil respiration was simulated by simulated temperature (OTC) and natural state. The results showed that the temperature of 5 cm soil was 1.37 °C higher than that of the control during the experiment, and the effect of warming was obvious. The respiration rate of soil under warming and natural conditions showed obvious diurnal variation and monthly variation. The effect of warming on soil respiration rate was promoted and the effect of precipitation on soil respiration rate was inhibited. Further studies have shown that the relationship between soil respiration and 5 cm soil temperature under the control and warming treatments can be described by the exponential equation, and the correlation analysis between the two plots shows a very significant exponential relationship (p < 0.001). The warming treatment not only increased the Q10 value of soil respiration rate, but also increased the sensitivity of soil respiration rate. The relationship between soil respiration and soil moisture can be explained by the quadratic linear equation (p < 0.05). It can be concluded that under the condition of sufficient rainfall, the soil temperature is the main influencing factor of soil respiration in this region.

  19. How much work is expended for respiration?

    PubMed

    Johnson, A T

    1993-01-01

    The rate of work expended to move air in the respiratory system has been determined for five different airflow waveshapes, a non-linear respiratory model and five exercise levels. As expected, the rectangular waveshape was the most efficient. Model conditions were then changed one a time: (i) starting lung volume was allowed to vary, (ii) exhalation flow limitation was added, (iii) respiration was considered to be a metabolic burden determining part of the ventilation requirement and (iv) a respirator mask was added. Although there is no direct work advantage to varying initial lung volume, such volume changes appear to be dictated by the asymmetry of lung recoil pressure about the lung relaxation volume; allowing the work of respiration to become a metabolic burden clearly shows why respiratory waveforms change from rest to exercise; and, adding a respirator imposes a severe respiratory burden on the wearer engaging in moderate, heavy and very heavy exercise.

  20. Do Tree Stems Recapture Respired CO2?

    NASA Astrophysics Data System (ADS)

    Hilman, B.; Angert, A.

    2016-12-01

    Tree stem respiration is an important, yet not well understood, component of the terrestrial carbon cycle. Predicting how trees as whole organisms respond to changes in climate and atmospheric CO2 requires understanding of the variability in the fraction of assimilated carbon allocated to respiration, versus the allocation to growth, damage repair, and to rhizosphere symbionts. Here we used the ratio of CO2 efflux/O2 influx (Apparent Respiratory Quotient, ARQ) to study stem respiration. The ARQ in trees stems is predicted to be 1.0, as a result of carbohydrates metabolism. Lower than 1.0 ARQ values may indicate a local assimilation of respired CO2, or dissolution and transport of CO2 in the xylem stream. We measured stems ARQ in 16 tree species at tropical, Mediterranean and temperate ecosystems using stem chambers and in-vitro incubations. The CO2 and O2 were measured by a system we developed, which is based on an IRGA and a Fuel-cell O2 analyzer (Hilman and Angert 2016). We found typical values of ARQ in the range of 0.4-0.8. Since incubations of detach stem tissues yielded similar ARQ values, and since the influence of natural variations in the transpiration stream on ARQ was found to be small, we conclude that the removal of the respired CO2 is not via dissolution in the xylem stream. Using 13C labeling, dark fixation of stem tissues was detected, which is most probably phosphoenolpyruvate carboxylase (PEPC) mediated. Hence, we suggest that in-stem dark fixation of respired CO2 to organic acids (e.g. malate) affects the outgoing efflux. Further research should determine if these organic acids are transported to the canopy, stored in the stem, or transported to the roots to serve as exudates. Hilman B, Angert A (2016) Measuring the ratio of CO2 efflux to O2 influx in tree stem respiration. Tree Physiol 2016, doi: 10.1093/treephys/tpw057

  1. 20 CFR 718.303 - Death from a respirable disease.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Death from a respirable disease. 718.303... Death from a respirable disease. (a)(1) If a deceased miner was employed for ten or more years in one or more coal mines and died from a respirable disease, there shall be a rebuttable presumption that his or...

  2. 30 CFR 70.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Respirable dust standard when quartz is present. When the respirable dust in the mine atmosphere of the... concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active... average concentration of respirable dust in the mine atmosphere associated with that mechanized mining...

  3. 30 CFR 70.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Respirable dust standard when quartz is present. When the respirable dust in the mine atmosphere of the... concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active... average concentration of respirable dust in the mine atmosphere associated with that mechanized mining...

  4. 30 CFR 70.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Respirable dust standard when quartz is present. When the respirable dust in the mine atmosphere of the... concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active... average concentration of respirable dust in the mine atmosphere associated with that mechanized mining...

  5. 30 CFR 70.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Respirable dust standard when quartz is present. When the respirable dust in the mine atmosphere of the... concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active... average concentration of respirable dust in the mine atmosphere associated with that mechanized mining...

  6. Breathing simulator of workers for respirator performance test

    PubMed Central

    YUASA, Hisashi; KUMITA, Mikio; HONDA, Takeshi; KIMURA, Kazushi; NOZAKI, Kosuke; EMI, Hitoshi; OTANI, Yoshio

    2014-01-01

    Breathing machines are widely used to evaluate respirator performance but they are capable of generating only limited air flow patterns, such as, sine, triangular and square waves. In order to evaluate the respirator performance in practical use, it is desirable to test the respirator using the actual breathing patterns of wearers. However, it has been a difficult task for a breathing machine to generate such complicated flow patterns, since the human respiratory volume changes depending on the human activities and workload. In this study, we have developed an electromechanical breathing simulator and a respiration sampling device to record and reproduce worker’s respiration. It is capable of generating various flow patterns by inputting breathing pattern signals recorded by a computer, as well as the fixed air flow patterns. The device is equipped with a self-control program to compensate the difference in inhalation and exhalation volume and the measurement errors on the breathing flow rate. The system was successfully applied to record the breathing patterns of workers engaging in welding and reproduced the breathing patterns. PMID:25382381

  7. Breathing simulator of workers for respirator performance test.

    PubMed

    Yuasa, Hisashi; Kumita, Mikio; Honda, Takeshi; Kimura, Kazushi; Nozaki, Kosuke; Emi, Hitoshi; Otani, Yoshio

    2015-01-01

    Breathing machines are widely used to evaluate respirator performance but they are capable of generating only limited air flow patterns, such as, sine, triangular and square waves. In order to evaluate the respirator performance in practical use, it is desirable to test the respirator using the actual breathing patterns of wearers. However, it has been a difficult task for a breathing machine to generate such complicated flow patterns, since the human respiratory volume changes depending on the human activities and workload. In this study, we have developed an electromechanical breathing simulator and a respiration sampling device to record and reproduce worker's respiration. It is capable of generating various flow patterns by inputting breathing pattern signals recorded by a computer, as well as the fixed air flow patterns. The device is equipped with a self-control program to compensate the difference in inhalation and exhalation volume and the measurement errors on the breathing flow rate. The system was successfully applied to record the breathing patterns of workers engaging in welding and reproduced the breathing patterns.

  8. Historical climate controls soil respiration responses to current soil moisture.

    PubMed

    Hawkes, Christine V; Waring, Bonnie G; Rocca, Jennifer D; Kivlin, Stephanie N

    2017-06-13

    Ecosystem carbon losses from soil microbial respiration are a key component of global carbon cycling, resulting in the transfer of 40-70 Pg carbon from soil to the atmosphere each year. Because these microbial processes can feed back to climate change, understanding respiration responses to environmental factors is necessary for improved projections. We focus on respiration responses to soil moisture, which remain unresolved in ecosystem models. A common assumption of large-scale models is that soil microorganisms respond to moisture in the same way, regardless of location or climate. Here, we show that soil respiration is constrained by historical climate. We find that historical rainfall controls both the moisture dependence and sensitivity of respiration. Moisture sensitivity, defined as the slope of respiration vs. moisture, increased fourfold across a 480-mm rainfall gradient, resulting in twofold greater carbon loss on average in historically wetter soils compared with historically drier soils. The respiration-moisture relationship was resistant to environmental change in field common gardens and field rainfall manipulations, supporting a persistent effect of historical climate on microbial respiration. Based on these results, predicting future carbon cycling with climate change will require an understanding of the spatial variation and temporal lags in microbial responses created by historical rainfall.

  9. Particulate Air Pollution: The Particulars

    ERIC Educational Resources Information Center

    Murphy, James E.

    1973-01-01

    Describes some of the causes and consequences of particulate air pollution. Outlines the experimental procedures for measuring the amount of particulate materials that settles from the air and for observing the nature of particulate air pollution. (JR)

  10. Resazurin as a Proxy for Estimating Stream Respiration

    NASA Astrophysics Data System (ADS)

    Gonzalez Pinzon, R. A.; Haggerty, R.; Argerich, A.; Briggs, M.; Lautz, L. K.; Lemke, D.; Hare, D. K.

    2010-12-01

    Hydrologic retention in stream ecosystems favors the reactions of solutes and nutrients in metabolically active transient storage (MATS) zones. These zones are hot spots where metabolic activity is expected to contribute significantly to ecosystem respiration. We compare the results of a series of coinjections of resazurin (Raz) as a redox sensitive tracer, and NaCl as a conservative tracer to investigate the function of MATS zones. Raz is a dye that undergoes an irreversible reduction to resorufin (Rru) when exposed to aerobic respiration. To characterize the transformation of Raz we measured the BTC of the tracers at the boundary conditions, and during plateau concentrations we sampled the longitudinal profile of surface water. We also used the two-station diel technique to quantify gross primary production (GPP) and community respiration (CR) within the reaches. Injections have been performed in streams with different morphology, streambed composition, and riparian vegetation in Oregon-USA (WS 1 and WS 3 in the HJ Andrews Forest LTER, and Drift Creek), Spain (Riera de Santa Fe del Montseny, Catalonia) and Wyoming-USA (Cherry Creek). The results support the idea that under different ranges of community respiration, the transformation of Raz to Rru is a proxy for quantifying MATS, characterizing spatial heterogeneity in respiration rates, and ultimately, could be used to estimate ecosystem respiration in environments where direct measurement is challenging.

  11. Abnormal mitochondrial respiration in failed human myocardium.

    PubMed

    Sharov, V G; Todor, A V; Silverman, N; Goldstein, S; Sabbah, H N

    2000-12-01

    Chronic heart failure (HF) is associated with morphologic abnormalities of cardiac mitochondria including hyperplasia, reduced organelle size and compromised structural integrity. In this study, we examined whether functional abnormalities of mitochondrial respiration are also present in myocardium of patients with advanced HF. Mitochondrial respiration was examined using a Clark electrode in an oxygraph cell containing saponin-skinned muscle bundles obtained from myocardium of failed explanted human hearts due to ischemic (ICM, n=9) or idiopathic dilated (IDC, n=9) cardiomyopathy. Myocardial specimens from five normal donor hearts served as controls (CON). Basal respiratory rate, respiratory rate after addition of the substrates glutamate and malate (V(SUB)), state 3 respiration (after addition of ADP, V(ADP)) and respiration after the addition of atractyloside (V(AT)) were measured in scar-free muscle bundles obtained from the subendocardial (ENDO) and subepicardial (EPI) thirds of the left ventricular (LV) free wall, interventricular septum and right ventricular (RV) free wall. There were no differences in basal and substrate-supported respiration between CON and HF regardless of etiology. V(ADP)was significantly depressed both in ICM and IDC compared to CON in all the regions studied. The respiratory control ratio, V(ADP)/V(AT), was also significantly decreased in HF compared to CON. In both ICM and IDC, V(ADP)was significantly lower in ENDO compared to EPI. The results indicate that mitochondrial respiration is abnormal in the failing human heart. The findings support the concept of low myocardial energy production in HF via oxidative phosphorylation, an abnormality with a potentially impact on global cardiac performance. Copyright 2000 Academic Press.

  12. Diesel exhaust particulate material expression of in vitro genotoxic activities when dispersed into a phospholipid component of lung surfactant

    NASA Astrophysics Data System (ADS)

    Shi, X. C.; Keane, M. J.; Ong, T. M.; Harrison, J. C.; Slaven, J. E.; Bugarski, A. D.; Gautam, M.; Wallace, W. E.

    2009-02-01

    Bacterial mutagenicity and mammalian cell chromosomal and DNA damage in vitro assays were performed on a diesel exhaust particulate material (DPM) standard in two preparations: as an organic solvent extract, and as an aqueous dispersion in a simulated pulmonary surfactant. U.S. National Institute for Standards and Technology DPM SRM 2975 expressed mutagenic activity in the Salmonella reversion assay, and for in vitro genotoxicity to mammalian cells as micronucleus induction and as DNA damage in both preparations: as an acetone extract of the DPM mixed into dimethylsulfoxide, and as a mixture of whole DPM in a dispersion of dipalmitoyl phosphatidyl choline. Dispersion in surfactant was used to model the conditioning of DPM depositing on the deep respiratory airways of the lung. DPM solid residue after acetone extraction was inactive when assayed as a surfactant dispersion in the micronucleus induction assay, as was surfactant dispersion of a respirable particulate carbon black. In general, a given mass of the DPM in surfactant dispersion expressed greater activity than the solvent extract of an equal mass of DPM.

  13. Discharge modulates stream metabolism dependence on fine particulate organic carbon in a Mediterranean WWTP-influenced stream

    NASA Astrophysics Data System (ADS)

    Drummond, J. D.; Bernal, S.; Meredith, W.; Schumer, R.; Martí Roca, E.

    2017-12-01

    Waste water treatment plant (WWTP) effluents constitute point source inputs of fine sediment, nutrients, carbon, and microbes to stream ecosystems. A range of responses to these inputs may be observed in recipient streams, including increases in respiration rates, which augment CO2 emissions to the atmosphere. Yet, little is known about which fractions of organic carbon (OC) contribute the most to stream metabolism in WWTP-influenced streams. Fine particulate OC (POC) represents ca. 40% of the total mass of OC in river networks, and is generally more labile than dissolved OC. Therefore, POC inputs from WWTPs could contribute disproportionately to higher rates of heterotrophic metabolism by stream microbial communities. The aim of this study was to investigate the influence of POC inputs from a WWTP effluent on the metabolism of a Mediterranean stream over a wide range of hydrologic conditions. We hypothesized that POC inputs would have a positive effect on respiration rates, and that the response to POC availability would be larger during low flows when the dilution capacity of the recipient stream is negligible. We focused on the easily resuspended fine sediment near the sediment-water interface (top 3 cm), as this region is a known hot spot for biogeochemical processes. For one year, samples of resuspended sediment were collected bimonthly at 7 sites from 0 to 800 m downstream of the WWTP point source. We measured total POC, organic matter (OM) content (%), and the associated metabolic activity of the resuspended sediment using the resazurin-resorufin smart tracer system as a proxy for aerobic ecosystem respiration. Resuspended sediment showed no difference in total POC over the year, while the OM content increased with decreasing discharge. This result together with the decreasing trend of total POC observed downstream of the point source during autumn after a long dry period, suggests that the WWTP effluent was the main contributor to stream POC. Furthermore

  14. Seasonality of temperate forest photosynthesis and daytime respiration.

    PubMed

    Wehr, R; Munger, J W; McManus, J B; Nelson, D D; Zahniser, M S; Davidson, E A; Wofsy, S C; Saleska, S R

    2016-06-30

    Terrestrial ecosystems currently offset one-quarter of anthropogenic carbon dioxide (CO2) emissions because of a slight imbalance between global terrestrial photosynthesis and respiration. Understanding what controls these two biological fluxes is therefore crucial to predicting climate change. Yet there is no way of directly measuring the photosynthesis or daytime respiration of a whole ecosystem of interacting organisms; instead, these fluxes are generally inferred from measurements of net ecosystem-atmosphere CO2 exchange (NEE), in a way that is based on assumed ecosystem-scale responses to the environment. The consequent view of temperate deciduous forests (an important CO2 sink) is that, first, ecosystem respiration is greater during the day than at night; and second, ecosystem photosynthetic light-use efficiency peaks after leaf expansion in spring and then declines, presumably because of leaf ageing or water stress. This view has underlain the development of terrestrial biosphere models used in climate prediction and of remote sensing indices of global biosphere productivity. Here, we use new isotopic instrumentation to determine ecosystem photosynthesis and daytime respiration in a temperate deciduous forest over a three-year period. We find that ecosystem respiration is lower during the day than at night-the first robust evidence of the inhibition of leaf respiration by light at the ecosystem scale. Because they do not capture this effect, standard approaches overestimate ecosystem photosynthesis and daytime respiration in the first half of the growing season at our site, and inaccurately portray ecosystem photosynthetic light-use efficiency. These findings revise our understanding of forest-atmosphere carbon exchange, and provide a basis for investigating how leaf-level physiological dynamics manifest at the canopy scale in other ecosystems.

  15. Root Zone Respiration on Hydroponically Grown Wheat Plant Systems

    NASA Technical Reports Server (NTRS)

    Soler-Crespo, R. A.; Monje, O. A.

    2010-01-01

    Root respiration is a biological phenomenon that controls plant growth and physiological development during a plant's lifespan. This process is dependent on the availability of oxygen in the system where the plant is located. In hydroponic systems, where plants are submerged in a solution containing vital nutrients but no type of soil, the availability of oxygen arises from the dissolved oxygen concentration in the solution. This oxygen concentration is dependent on the , gas-liquid interface formed on the upper surface of the liquid, as given by Henry's Law, depending on pressure and temperature conditions. Respiration rates of the plants rise as biomass and root zone increase with age. The respiration rate of Apogee wheat plants (Triticum aestivum) was measured as a function of light intensity (catalytic for photosynthesis) and CO2 concentration to determine their effect on respiration rates. To determine their effects on respiration rate and plant growth microbial communities were introduced into the system, by Innoculum. Surfactants were introduced, simulating gray-water usage in space, as another factor to determine their effect on chemical oxygen demand of microbials and on respiration rates of the plants. It is expected to see small effects from changes in CO2 concentration or light levels, and to see root respiration decrease in an exponential manner with plant age and microbial activity.

  16. Direct reading of electrocardiograms and respiration rates

    NASA Technical Reports Server (NTRS)

    Wise, J. P.

    1969-01-01

    Technique for reading heart and respiration rates is more accurate and direct than the previous method. Index of a plastic calibrated card is aligned with a point on the electrocardiogram. Complexes are counted as indicated on the card and heart or respiration rate is read directly from the appropriate scale.

  17. Thinning but not understory removal increased heterotrophic respiration and total soil respiration in Pinus massoniana stands.

    PubMed

    Lei, Lei; Xiao, Wenfa; Zeng, Lixiong; Zhu, Jianhua; Huang, Zhilin; Cheng, Ruimei; Gao, Shangkun; Li, Mai-He

    2018-04-15

    Quantifying soil respiration (R s ) and its components [autotrophic respiration (R a ) and heterotrophic respiration (R h )] in relation to forest management is vital to accurately evaluate forest carbon balance. Thus, R s , R a , and R h were continuously monitored from November 2013 to November 2016 in Pinus massoniana forests subjected to four different management practices in China. We hypothesized that understory removal and thinning decrease R a and R h and thus R s , and these decreases will change with time following UR and thinning. Mean values of R s , R a , and R h in light thinned plots (LT=15% of tree basal area thinned) and heavily thinned plots (HT=70% of tree basal area thinned) were significantly higher than in control (CK) and understory removal plots (UR). The annual R h /R s ratio ranged from 58% to 70% across all treatments, and this ratio was significantly higher in HT and LT than in UR and CK. Only HT significantly increased soil temperature. Soil temperature could better explain R h (R 2 =0.69-0.96) than R a (R 2 =0.51-0.86). HT and LT increased Q 10 for both R a and R h , except for R h in UR. Soil moisture content (W; %) was significantly higher in HT than in other treatments, but W had limited effects on soil respiration in that rain-rich subtropical China. This result suggests that global warming alone, or in combination with clear-cutting or canopy tree thinning will markedly increase soil heterotrophic respiration and thus the total soil CO 2 emission. To get firewood for local people and to reduce soil CO 2 emissions under global warming, canopy trees are needed to be protected and understory shrubs may be allowed to be used in the subtropical China. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Pitch based foam with particulate

    DOEpatents

    Klett, James W.

    2001-01-01

    A thermally conductive, pitch based foam composite having a particulate content. The particulate alters the mechanical characteristics of the foam without severely degrading the foam thermal conductivity. The composite is formed by mixing the particulate with pitch prior to foaming.

  19. Moisture Limitations Dominate the Seasonality of Heterotrophic Respiration in the Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Konings, A. G.; Bloom, A. A.; Liu, J.; Parazoo, N.; Schimel, D.; Bowman, K. W.

    2016-12-01

    Heterotrophic respiration is the dominant process causing the loss of soil organic carbon, the largest stock of carbon on earth. Temperature, soil moisture, substrate availability, and soil microbial composition can all affect the rate of heterotrophic respiration. Without isotopic or root-specific measurements, it can be difficult to separate the total soil respiration into autotrophic and heterotrophic respiration. As a result, the large-scale variability and seasonality of heterotrophic respiration remains unknown, especially outside the mid-latitudes. In this study, we use remote-sensing based observational constraints to estimate heterotrophic respiration at large scales. We combine net ecosystem exchange estimates from atmospheric inversions of the Carbon Monitoring System-Flux project (CMS-Flux) with a recently derived optimally-scaled GPP dataset based on satellite-observed solar-induced fluorescence variations to estimate total ecosystem respiration. The ecosystem respiration is then separated into autotrophic and heterotrophic components based on a spatially-varying carbon use efficiency retrieved in a model-data fusion framework (CARDAMOM). The three datasets are combined into a Bayesian framework to derive the uncertainty distribution of global heterotrophic respiration allowing only physically realistic solutions (appropriate signs for all fluxes), In most Southern Hemisphere regions where precipitation and temperature are anti-correlated (e.g. dry African woodlands, Sahel, Southern India, etc..), the seasonality of heterotrophic respiration follows precipitation, not temperature. This results in an apparent anti-correlation between heterotrophic respiration and temperature. By comparison, a data-constrained terrestrial ecosystem model that does not simulate an effect of soil moisture on heterotrophic respiration did not show this anti-correlation. Data-driven heterotrophic respiration estimates such as those presented here may be used to benchmark

  20. Electrical diesel particulate filter (DPF) regeneration

    DOEpatents

    Gonze, Eugene V; Ament, Frank

    2013-12-31

    An exhaust system that processes exhaust generated by an engine includes a diesel particulate filter (DPF) that is disposed downstream of the engine and that filters particulates from the exhaust. An electrical heater is disposed upstream of the DPF and selectively heats the exhaust to initiate combustion of the particulates within the exhaust as it passes therethrough. Heat generated by combustion of the particulates induces combustion of particulates within the DPF.

  1. 30 CFR 57.11059 - Respirable atmosphere for hoist operators underground.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Respirable atmosphere for hoist operators... NONMETAL MINES Travelways and Escapeways Escapeways-Underground Only § 57.11059 Respirable atmosphere for... be provided with a respirable atmosphere completely independent of the mine atmosphere. This...

  2. 30 CFR 57.11059 - Respirable atmosphere for hoist operators underground.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Respirable atmosphere for hoist operators... NONMETAL MINES Travelways and Escapeways Escapeways-Underground Only § 57.11059 Respirable atmosphere for... be provided with a respirable atmosphere completely independent of the mine atmosphere. This...

  3. 30 CFR 57.11059 - Respirable atmosphere for hoist operators underground.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Respirable atmosphere for hoist operators... NONMETAL MINES Travelways and Escapeways Escapeways-Underground Only § 57.11059 Respirable atmosphere for... be provided with a respirable atmosphere completely independent of the mine atmosphere. This...

  4. 30 CFR 57.11059 - Respirable atmosphere for hoist operators underground.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Respirable atmosphere for hoist operators... NONMETAL MINES Travelways and Escapeways Escapeways-Underground Only § 57.11059 Respirable atmosphere for... be provided with a respirable atmosphere completely independent of the mine atmosphere. This...

  5. Assessing SOC labile fractions through respiration test, density-size fractionation and thermal analysis - A comparison of methods

    NASA Astrophysics Data System (ADS)

    Soucemarianadin, Laure; Cécillon, Lauric; Chenu, Claire; Baudin, François; Nicolas, Manuel; Savignac, Florence; Barré, Pierre

    2017-04-01

    Soil organic matter (SOM) is the biggest terrestrial carbon reservoir, storing 3 to 4 times more carbon than the atmosphere. However, despite its major importance for climate regulation SOM dynamics remains insufficiently understood. For instance, there is still no widely accepted method to assess SOM lability. Soil respiration tests and particulate organic matter (POM) obtained by different fractionation schemes have been used for decades and are now considered as classical estimates of very labile and labile soil organic carbon (SOC), respectively. But the pertinence of these methods to characterize SOM turnover can be questioned. Moreover, they are very time-consuming and their reproducibility might be an issue. Alternate ways of determining the labile SOC component are thus well-needed. Thermal analyses have been used to characterize SOM among which Rock-Eval 6 (RE6) analysis of soil has shown promising results in the determination of SOM biogeochemical stability (Gregorich et al., 2015; Barré et al., 2016). Using a large set of samples of French forest soils representing contrasted pedoclimatic conditions, including deep samples (up to 1 m depth), we compared different techniques used for SOM lability assessment. We explored whether results from soil respiration test (10-week laboratory incubations), SOM size-density fractionation and RE6 thermal analysis were comparable and how they were correlated. A set of 222 (respiration test and RE6), 103 (SOM fractionation and RE6) and 93 (respiration test, SOM fractionation and RE6) forest soils samples were respectively analyzed and compared. The comparison of the three methods (n = 93) using a principal component analysis separated samples from the surface (0-10 cm) and deep (40-80 cm) layers, highlighting a clear effect of depth on the short-term persistence of SOC. A correlation analysis demonstrated that, for these samples, the two classical methods of labile SOC determination (respiration and SOM fractionation

  6. Transcriptional regulation of respiration in yeast metabolizing differently repressive carbon substrates.

    PubMed

    Fendt, Sarah-Maria; Sauer, Uwe

    2010-02-18

    Depending on the carbon source, Saccharomyces cerevisiae displays various degrees of respiration. These range from complete respiration as in the case of ethanol, to almost complete fermentation, and thus very low degrees of respiration on glucose. While many key regulators are known for these extreme cases, we focus here on regulators that are relevant at intermediate levels of respiration. We address this question by linking the functional degree of respiration to transcriptional regulation via enzyme abundances. Specifically, we investigated aerobic batch cultures with the differently repressive carbon sources glucose, mannose, galactose and pyruvate. Based on 13C flux analysis, we found that the respiratory contribution to cellular energy production was largely absent on glucose and mannose, intermediate on galactose and highest on pyruvate. In vivo abundances of 40 respiratory enzymes were quantified by GFP-fusions under each condition. During growth on the partly and fully respired substrates galactose and pyruvate, several TCA cycle and respiratory chain enzymes were significantly up-regulated. From these enzyme levels and the known regulatory network structure, we determined the probability for a given transcription factor to cause the coordinated expression changes. The most probable transcription factors to regulate the different degrees of respiration were Gcr1p, Cat8p, the Rtg-proteins and the Hap-complex. For the latter three ones we confirmed their importance for respiration by quantifying the degree of respiration and biomass yields in the corresponding deletion strains. Cat8p is required for wild-type like respiration, independent of its known activation of gluconeogenic genes. The Rtg-proteins and the Hap-complex are essential for wild-type like respiration under partially respiratory conditions. Under fully respiratory conditions, the Hap-complex, but not the Rtg-proteins are essential for respiration.

  7. Temperature response of soil respiration largely unaltered with experimental warming.

    PubMed

    Carey, Joanna C; Tang, Jianwu; Templer, Pamela H; Kroeger, Kevin D; Crowther, Thomas W; Burton, Andrew J; Dukes, Jeffrey S; Emmett, Bridget; Frey, Serita D; Heskel, Mary A; Jiang, Lifen; Machmuller, Megan B; Mohan, Jacqueline; Panetta, Anne Marie; Reich, Peter B; Reinsch, Sabine; Wang, Xin; Allison, Steven D; Bamminger, Chris; Bridgham, Scott; Collins, Scott L; de Dato, Giovanbattista; Eddy, William C; Enquist, Brian J; Estiarte, Marc; Harte, John; Henderson, Amanda; Johnson, Bart R; Larsen, Klaus Steenberg; Luo, Yiqi; Marhan, Sven; Melillo, Jerry M; Peñuelas, Josep; Pfeifer-Meister, Laurel; Poll, Christian; Rastetter, Edward; Reinmann, Andrew B; Reynolds, Lorien L; Schmidt, Inger K; Shaver, Gaius R; Strong, Aaron L; Suseela, Vidya; Tietema, Albert

    2016-11-29

    The respiratory release of carbon dioxide (CO 2 ) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific attention in recent decades, the overall response of soil respiration to anticipated climatic warming remains unclear. We synthesize the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3,800 observations representing 27 temperature manipulation studies, spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation of soil respiration to experimental warming in several major biome types, contrary to the results from multiple single-site studies. Moreover, across all nondesert biomes, respiration rates with and without experimental warming follow a Gaussian response, increasing with soil temperature up to a threshold of ∼25 °C, above which respiration rates decrease with further increases in temperature. This consistent decrease in temperature sensitivity at higher temperatures demonstrates that rising global temperatures may result in regionally variable responses in soil respiration, with colder climates being considerably more responsive to increased ambient temperatures compared with warmer regions. Our analysis adds a unique cross-biome perspective on the temperature response of soil respiration, information critical to improving our mechanistic understanding of how soil carbon dynamics change with climatic warming.

  8. Temperature response of soil respiration largely unaltered with experimental warming

    USGS Publications Warehouse

    Carey, Joanna C.; Tang, Jianwu; Templer, Pamela H.; Kroeger, Kevin D.; Crowther, Thomas W.; Burton, Andrew J.; Dukes, Jeffrey S.; Emmett, Bridget; Frey, Serita D.; Heskel, Mary A.; Jiang, Lifen; Machmuller, Megan B.; Mohan, Jacqueline; Panetta, Anne Marie; Reich, Peter B.; Reinsch, Sabine; Wang, Xin; Allison, Steven D.; Bamminger, Chris; Bridgham, Scott; Collins, Scott L.; de Dato, Giovanbattista; Eddy, William C.; Enquist, Brian J.; Estiarte, Marc; Harte, John; Henderson, Amanda; Johnson, Bart R.; Steenberg Larsen, Klaus; Luo, Yiqi; Marhan, Sven; Melillo, Jerry M.; Penuelas, Josep; Pfeifer-Meister, Laurel; Poll, Christian; Rastetter, Edward B.; Reinmann, Andrew B.; Reynolds, Lorien L.; Schmidt, Inger K.; Shaver, Gaius R.; Strong, Aaron L.; Suseela, Vidya; Tietema, Albert

    2016-01-01

    The respiratory release of carbon dioxide (CO2) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific attention in recent decades, the overall response of soil respiration to anticipated climatic warming remains unclear. We synthesize the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3,800 observations representing 27 temperature manipulation studies, spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation of soil respiration to experimental warming in several major biome types, contrary to the results from multiple single-site studies. Moreover, across all nondesert biomes, respiration rates with and without experimental warming follow a Gaussian response, increasing with soil temperature up to a threshold of ∼25 °C, above which respiration rates decrease with further increases in temperature. This consistent decrease in temperature sensitivity at higher temperatures demonstrates that rising global temperatures may result in regionally variable responses in soil respiration, with colder climates being considerably more responsive to increased ambient temperatures compared with warmer regions. Our analysis adds a unique cross-biome perspective on the temperature response of soil respiration, information critical to improving our mechanistic understanding of how soil carbon dynamics change with climatic warming.

  9. Temperature response of soil respiration largely unaltered with experimental warming

    PubMed Central

    Carey, Joanna C.; Tang, Jianwu; Templer, Pamela H.; Kroeger, Kevin D.; Crowther, Thomas W.; Burton, Andrew J.; Dukes, Jeffrey S.; Emmett, Bridget; Frey, Serita D.; Heskel, Mary A.; Jiang, Lifen; Machmuller, Megan B.; Mohan, Jacqueline; Panetta, Anne Marie; Reich, Peter B.; Reinsch, Sabine; Wang, Xin; Allison, Steven D.; Bamminger, Chris; Bridgham, Scott; de Dato, Giovanbattista; Eddy, William C.; Enquist, Brian J.; Estiarte, Marc; Harte, John; Henderson, Amanda; Johnson, Bart R.; Luo, Yiqi; Marhan, Sven; Melillo, Jerry M.; Peñuelas, Josep; Pfeifer-Meister, Laurel; Poll, Christian; Rastetter, Edward; Reinmann, Andrew B.; Reynolds, Lorien L.; Schmidt, Inger K.; Shaver, Gaius R.; Strong, Aaron L.; Suseela, Vidya; Tietema, Albert

    2016-01-01

    The respiratory release of carbon dioxide (CO2) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific attention in recent decades, the overall response of soil respiration to anticipated climatic warming remains unclear. We synthesize the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3,800 observations representing 27 temperature manipulation studies, spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation of soil respiration to experimental warming in several major biome types, contrary to the results from multiple single-site studies. Moreover, across all nondesert biomes, respiration rates with and without experimental warming follow a Gaussian response, increasing with soil temperature up to a threshold of ∼25 °C, above which respiration rates decrease with further increases in temperature. This consistent decrease in temperature sensitivity at higher temperatures demonstrates that rising global temperatures may result in regionally variable responses in soil respiration, with colder climates being considerably more responsive to increased ambient temperatures compared with warmer regions. Our analysis adds a unique cross-biome perspective on the temperature response of soil respiration, information critical to improving our mechanistic understanding of how soil carbon dynamics change with climatic warming. PMID:27849609

  10. Respiratory Protection Toolkit: Providing Guidance Without Changing Requirements-Can We Make an Impact?

    PubMed

    Bien, Elizabeth Ann; Gillespie, Gordon Lee; Betcher, Cynthia Ann; Thrasher, Terri L; Mingerink, Donna R

    2016-12-01

    International travel and infectious respiratory illnesses worldwide place health care workers (HCWs) at increasing risk of respiratory exposures. To ensure the highest quality safety initiatives, one health care system used a quality improvement model of Plan-Do-Study-Act and guidance from Occupational Safety and Health Administration's (OSHA) May 2015 Hospital Respiratory Protection Program (RPP) Toolkit to assess a current program. The toolkit aided in identification of opportunities for improvement within their well-designed RPP. One opportunity was requiring respirator use during aerosol-generating procedures for specific infectious illnesses. Observation data demonstrated opportunities to mitigate controllable risks including strap placement, user seal check, and reuse of disposable N95 filtering facepiece respirators. Subsequent interdisciplinary collaboration resulted in other ideas to decrease risks and increase protection from potentially infectious respiratory illnesses. The toolkit's comprehensive document to evaluate the program showed that while the OSHA standards have not changed, the addition of the toolkit can better protect HCWs. © 2016 The Author(s).

  11. Reductions in the variations of respiration signals for respiratory-gated radiotherapy when using the video-coaching respiration guiding system

    NASA Astrophysics Data System (ADS)

    Lee, Hyun Jeong; Yea, Ji Woon; Oh, Se An

    2015-07-01

    Respiratory-gated radiation therapy (RGRT) has been used to minimize the dose to normal tissue in lung-cancer radiotherapy. The present research aims to improve the regularity of respiration in RGRT by using a video-coached respiration guiding system. In the study, 16 patients with lung cancer were evaluated. The respiration signals of the patients were measured by using a realtime position management (RPM) respiratory gating system (Varian, USA), and the patients were trained using the video-coaching respiration guiding system. The patients performed free breathing and guided breathing, and the respiratory cycles were acquired for ~5 min. Then, Microsoft Excel 2010 software was used to calculate the mean and the standard deviation for each phase. The standard deviation was computed in order to analyze the improvement in the respiratory regularity with respect to the period and the displacement. The standard deviation of the guided breathing decreased to 48.8% in the inhale peak and 24.2% in the exhale peak compared with the values for the free breathing of patient 6. The standard deviation of the respiratory cycle was found to be decreased when using the respiratory guiding system. The respiratory regularity was significantly improved when using the video-coaching respiration guiding system. Therefore, the system is useful for improving the accuracy and the efficiency of RGRT.

  12. Hydrocarbon-enhanced particulate filter regeneration via microwave ignition

    DOEpatents

    Gonze, Eugene V.; Brown, David B.

    2010-02-02

    A regeneration method for a particulate filter includes estimating a quantity of particulate matter trapped within the particulate filter, comparing the quantity of particulate matter to a predetermined quantity, heating at least a portion of the particulate filter to a combustion temperature of the particulate matter, and introducing hydrocarbon fuel to the particulate filter. The hydrocarbon fuel facilitates combustion of the particulate matter to regenerate the particulate filter.

  13. Global variability in leaf respiration in relation to climate and leaf traits

    NASA Astrophysics Data System (ADS)

    Atkin, Owen K.

    2015-04-01

    Leaf respiration plays a vital role in regulating ecosystem functioning and the Earth's climate. Because of this, it is imperative that that Earth-system, climate and ecosystem-level models be able to accurately predict variations in rates of leaf respiration. In the field of photosynthesis research, the F/vC/B model has enabled modellers to accurately predict variations in photosynthesis through time and space. By contrast, we lack an equivalent biochemical model to predict variations in leaf respiration. Consequently, we need to rely on phenomenological approaches to model variations in respiration across the Earth's surface. Such approaches require that we develop a thorough understanding of how rates of respiration vary among species and whether global environmental gradients play a role in determining variations in leaf respiration. Dealing with these issues requires that data sets be assembled on rates of leaf respiration in biomes across the Earth's surface. In this talk, I will use a newly-assembled global database on leaf respiration and associated traits (including photosynthesis) to highlight variation in leaf respiration (and the balance between respiration and photosynthesis) across global gradients in growth temperature and aridity.

  14. Temporal changes of soil respiration under different tree species.

    PubMed

    Akburak, Serdar; Makineci, Ender

    2013-04-01

    Soil respiration rates were measured monthly (from April 2007 to March 2008) under four adjacent coniferous plantation sites [Oriental spruce (Picea orientalis L.), Austrian pine (Pinus nigra Arnold), Turkish fir (Abies bornmulleriana L.), and Scots pine (Pinus sylvestris L.)] and adjacent natural Sessile oak forest (Quercus petraea L.) in Belgrad Forest-Istanbul/Turkey. Also, soil moisture, soil temperature, and fine root biomass were determined to identify the underlying environmental variables among sites which are most likely causing differences in soil respiration. Mean annual soil moisture was determined to be between 6.3 % and 8.1 %, and mean annual temperature ranged from 13.0°C to 14.2°C under all species. Mean annual fine root biomass changed between 368.09 g/m(2) and 883.71 g/m(2) indicating significant differences among species. Except May 2007, monthly soil respiration rates show significantly difference among species. However, focusing on tree species, differences of mean annual respiration rates did not differ significantly. Mean annual soil respiration ranged from 0.56 to 1.09 g C/m(2)/day. The highest rates of soil respiration reached on autumn months and the lowest rates were determined on summer season. Soil temperature, soil moisture, and fine root biomass explain mean annual soil respiration rates at the highest under Austrian pine (R (2) = 0.562) and the lowest (R (2) = 0.223) under Turkish fir.

  15. Prototype sampling system for measuring workplace protection factors for gases and vapors.

    PubMed

    Groves, William A; Reynolds, Stephen J

    2003-05-01

    A prototype sampling system for measuring respirator workplace protection factors (WPFs) was developed. Methods for measuring the concentration of contaminants inside respirators have previously been described; however, these studies have typically involved continuous sampling of aerosols. Our work focuses on developing an intermittent sampling system designed to measure the concentration of gases and vapors during inspiration. This approach addresses two potential problems associated with continuous sampling: biased results due to lower contaminant concentrations and high humidity in exhaled air. The system consists of a pressure transducer circuit designed to activate a pair of personal sampling pumps during inspiration based on differential pressure inside the respirator. One pump draws air from inside the respirator while the second samples the ambient air. Solid granular adsorbent tubes are used to trap the contaminants, making the approach applicable to a large number of gases and vapors. Laboratory testing was performed using a respirator mounted on a headform connected to a breathing machine producing a sinusoidal flow pattern with an average flow rate of 20 L/min and a period of 3 seconds. The sampling system was adjusted to activate the pumps when the pressure inside the respirator was less than -0.1 inch H(2)O. Quantitative fit-tests using human subjects were conducted to evaluate the effect of the sampling system on respirator performance. A total of 299 fit-tests were completed for two different types of respirators (half- and full-facepiece) from two different manufacturers (MSA and North). Statistical tests showed no significant differences between mean fit factors for respirators equipped with the sampling system versus unmodified respirators. Field testing of the prototype sampling system was performed in livestock production facilities and estimates of WPFs for ammonia were obtained. Results demonstrate the feasibility of this approach and will be

  16. Electrically heated particulate filter restart strategy

    DOEpatents

    Gonze, Eugene V [Pinckney, MI; Ament, Frank [Troy, MI

    2011-07-12

    A control system that controls regeneration of a particulate filter is provided. The system generally includes a propagation module that estimates a propagation status of combustion of particulate matter in the particulate filter. A regeneration module controls current to the particulate filter to re-initiate regeneration based on the propagation status.

  17. 30 CFR 57.5075 - Diesel particulate records.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Diesel particulate records. 57.5075 Section 57..., Radiation, Physical Agents, and Diesel Particulate Matter Diesel Particulate Matter-Underground Only § 57.5075 Diesel particulate records. (a) The table entitled “Diesel Particulate Matter Recordkeeping...

  18. 30 CFR 57.5075 - Diesel particulate records.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Diesel particulate records. 57.5075 Section 57..., Radiation, Physical Agents, and Diesel Particulate Matter Diesel Particulate Matter-Underground Only § 57.5075 Diesel particulate records. (a) The table entitled “Diesel Particulate Matter Recordkeeping...

  19. 29 CFR 1910.134 - Respiratory protection.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... impact and penetration. High efficiency particulate air (HEPA) filter means a filter that is at least 99... as a high efficiency particulate air (HEPA) filter, or an air-purifying respirator equipped with a... frequency of respirator use (including use for rescue and escape); (C) The expected physical work effort; (D...

  20. 29 CFR 1910.134 - Respiratory protection.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... impact and penetration. High efficiency particulate air (HEPA) filter means a filter that is at least 99... as a high efficiency particulate air (HEPA) filter, or an air-purifying respirator equipped with a... frequency of respirator use (including use for rescue and escape); (C) The expected physical work effort; (D...

  1. 29 CFR 1910.134 - Respiratory protection.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... impact and penetration. High efficiency particulate air (HEPA) filter means a filter that is at least 99... as a high efficiency particulate air (HEPA) filter, or an air-purifying respirator equipped with a... frequency of respirator use (including use for rescue and escape); (C) The expected physical work effort; (D...

  2. Hybrid respiration in the denitrifying mitochondria of Fusarium oxysporum.

    PubMed

    Takaya, Naoki; Kuwazaki, Seigo; Adachi, Yoshiaki; Suzuki, Sawako; Kikuchi, Tomoko; Nakamura, Hiro; Shiro, Yoshitsugu; Shoun, Hirofumi

    2003-04-01

    Induction of the mitochondrial nitrate-respiration (denitrification) system of the fungus Fusarium oxysporum requires the supply of low levels of oxygen (O(2)). Here we show that O(2) and nitrate (NO(3)(-)) respiration function simultaneously in the mitochondria of fungal cells incubated under hypoxic, denitrifying conditions in which both O(2) and NO(3)(-) act as the terminal electron acceptors. The NO(3)(-) and nitrite (NO(2)(-)) reductases involved in fungal denitrification share the mitochondrial respiratory chain with cytochrome oxidase. F. oxysporum cytochrome c(549) can serve as an electron donor for both NO(2)(-) reductase and cytochrome oxidase. We are the first to demonstrate hybrid respiration in respiring eukaryotic mitochondria.

  3. Respiration in Aquatic Insects.

    ERIC Educational Resources Information Center

    MacFarland, John

    1985-01-01

    This article: (1) explains the respiratory patterns of several freshwater insects; (2) describes the differences and mechanisms of spiracular cutaneous, and gill respiration; and (3) discusses behavioral aspects of selected aquatic insects. (ML)

  4. Dynamic characteristics of soil respiration in Yellow River Delta wetlands, China

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Luo, Xianxiang; Jia, Hongli; Zheng, Hao

    2018-02-01

    The stable soil carbon (C) pool in coastal wetlands, referred to as "blue C", which has been extensively damaged by climate change and soil degradation, is of importance to maintain global C cycle. Therefore, to investigate the dynamic characteristics of soil respiration rate and evaluate C budgets in coastal wetlands are urgently. In this study, the diurnal and seasonal variation of soil respiration rate in the reed wetland land (RL) and the bare wetland land (BL) was measured in situ with the dynamic gas-infrared CO2 method in four seasons, and the factors impacted on the dynamic characteristics of soil respiration were investigated. The results showed that the diurnal variation of soil respiration rate consistently presented a "U" curve pattern in April, July, and September, with the maximum values at 12:00 a.m. and the minimum values at 6:00 a.m. In the same season, the diurnal soil respiration rate in RL was significantly greater than those in BL (P < 0.05). In April, July, and September, the mean diurnal soil respiration rate was 0.14, 0.42, and 0.39 μmol m-2 s-1 in RL, 0.05, 0.22, 0.13, and 0.01 μmol m-2 s-1 in BL, respectively. Soil surface temperature was the primary factor that influenced soil respiration, which was confirmed by the exponential positive correlation between the soil respiration rate and soil surface temperature in BL and RL (P < 0.05). In addition, the high salinity of soils suppressed soil respiration, confirming by the significantly negative correlation between soil respiration rate and the content of soluble salt. These results will be useful for understanding the mechanisms underlying soil respiration and elevating C sequestration potential in the coastal wetlands.

  5. Respiratory Source Control Using Surgical Masks With Nanofiber Media

    PubMed Central

    Skaria, Shaji D.; Smaldone, Gerald C.

    2014-01-01

    Background: Potentially infected individuals (‘source’) are sometimes encouraged to use face masks to reduce exposure of their infectious aerosols to others (‘receiver’). To improve compliance with Respiratory Source Control via face mask and therefore reduce receiver exposure, a mask should be comfortable and effective. We tested a novel face mask designed to improve breathability and filtration using nanofiber filtration. Methods: Using radiolabeled test aerosols and a calibrated exposure chamber simulating source to receiver interaction, facepiece function was measured with a life-like ventilated manikin model. Measurements included mask airflow resistance (pressure difference during breathing), filtration, (mask capture of exhaled radiolabeled test aerosols), and exposure (the transfer of ‘infectious’ aerosols from the ‘source’ to a ‘receiver’). Polydisperse aerosols were measured at the source with a mass median aerodynamic diameter of 0.95 µm. Approximately 90% of the particles were <2.0 µm. Tested facepieces included nanofiber prototype surgical masks, conventional surgical masks, and for comparison, an N95-class filtering facepiece respirator (commonly known as an ‘N95 respirator’). Airflow through and around conventional surgical face mask and nanofiber prototype face mask was visualized using Schlieren optical imaging. Results: Airflow resistance [ΔP, cmH2O] across sealed surgical masks (means: 0.1865 and 0.1791 cmH2O) approached that of the N95 (mean: 0.2664 cmH2O). The airflow resistance across the nanofiber face mask whether sealed or not sealed (0.0504 and 0.0311 cmH2O) was significantly reduced in comparison. In addition, ‘infected’ source airflow filtration and receiver exposure levels for nanofiber face masks placed on the source were comparable to that achieved with N95 placed on the source; 98.98% versus 82.68% and 0.0194 versus 0.0557, respectively. Compared to deflection within and around the conventional face

  6. Ozone removal capability of a welding fume respirator containing activated charcoal.

    PubMed

    Johnston, A R; Dyrud, J F; Shih, Y T

    1989-09-01

    Development of air purifying respirators for protection against ozone has been slowed by concerns about oxidation of charcoal and other available sorbents. The suitability of a charcoal sorbent for low concentrations of ozone was evaluated as a part of the development of a half-mask air purifying respirator designed for welding fumes and ozone. Testing of the respirator confirmed that charcoal can be a suitable sorbent for low levels of ozone. Where the respirator is properly selected, fit tested, and worn, respirator use against welding fumes and ozone at concentrations not exceeding 10 times the permissible exposure limit had been recommended.

  7. BACTERIAL RESPIRATION OF ARSENIC AND SELENIUM. (R826105)

    EPA Science Inventory

    Abstract

    Oxyanions of arsenic and selenium can be used in microbial anaerobic respiration as terminal electron acceptors. The detection of arsenate and selenate respiring bacteria in numerous pristine and contaminated environments and their rapid appearance in enrichme...

  8. Soil Respiration in Semiarid Temperate Grasslands under Various Land Management

    PubMed Central

    Hou, Xiangyang; Schellenberg, Michael P.

    2016-01-01

    Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures) on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17μmol.m−2.s−1) and clipping (2.06μmol.m−2.s−1) than under grazing (1.65μmol.m−2.s−1) over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP). Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP) and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content) and biotic (ANPP and BNPP) factors regulate soil respiration in the semiarid temperate grassland of northern China. PMID:26808376

  9. Historical climate controls soil respiration responses to current soil moisture

    PubMed Central

    Waring, Bonnie G.; Rocca, Jennifer D.; Kivlin, Stephanie N.

    2017-01-01

    Ecosystem carbon losses from soil microbial respiration are a key component of global carbon cycling, resulting in the transfer of 40–70 Pg carbon from soil to the atmosphere each year. Because these microbial processes can feed back to climate change, understanding respiration responses to environmental factors is necessary for improved projections. We focus on respiration responses to soil moisture, which remain unresolved in ecosystem models. A common assumption of large-scale models is that soil microorganisms respond to moisture in the same way, regardless of location or climate. Here, we show that soil respiration is constrained by historical climate. We find that historical rainfall controls both the moisture dependence and sensitivity of respiration. Moisture sensitivity, defined as the slope of respiration vs. moisture, increased fourfold across a 480-mm rainfall gradient, resulting in twofold greater carbon loss on average in historically wetter soils compared with historically drier soils. The respiration–moisture relationship was resistant to environmental change in field common gardens and field rainfall manipulations, supporting a persistent effect of historical climate on microbial respiration. Based on these results, predicting future carbon cycling with climate change will require an understanding of the spatial variation and temporal lags in microbial responses created by historical rainfall. PMID:28559315

  10. Microbial Iron Respiration Can Protect Steel from Corrosion

    PubMed Central

    Dubiel, M.; Hsu, C. H.; Chien, C. C.; Mansfeld, F.; Newman, D. K.

    2002-01-01

    Microbiologically influenced corrosion (MC) of steel has been attributed to the activity of biofilms that include anaerobic microorganisms such as iron-respiring bacteria, yet the mechanisms by which these organisms influence corrosion have been unclear. To study this process, we generated mutants of the iron-respiring bacterium Shewanella oneidensis strain MR-1 that were defective in biofilm formation and/or iron reduction. Electrochemical impedance spectroscopy was used to determine changes in the corrosion rate and corrosion potential as a function of time for these mutants in comparison to the wild type. Counter to prevailing theories of MC, our results indicate that biofilms comprising iron-respiring bacteria may reduce rather than accelerate the corrosion rate of steel. Corrosion inhibition appears to be due to reduction of ferric ions to ferrous ions and increased consumption of oxygen, both of which are direct consequences of microbial respiration. PMID:11872499

  11. BOREAS TE-2 Wood Respiration Data

    NASA Technical Reports Server (NTRS)

    Ryan, Michael G.; Lavigne, Michael; Hall, Forrest G. (Editor); Papagno, Andrea (Editor)

    2000-01-01

    The BOREAS TE-2 team collected several data sets in support of its efforts to characterize and interpret information on the respiration of the foliage, roots, and wood of boreal vegetation. This data set contains measurements of wood respiration conducted in the NSA during the growing season of 1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  12. BOREAS TE-2 Foliage Respiration Data

    NASA Technical Reports Server (NTRS)

    Ryan, Michael G.; Hall, Forrest G. (Editor); Lavigne, Michael; Papagno, Andrea (Editor)

    2000-01-01

    The BOREAS TE-2 team collected several data sets in support of its efforts to characterize and interpret information on the respiration of the foliage, roots, and wood of boreal vegetation. This data set contains measurements of foliar respiration conducted in the NSA during the growing season of 1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  13. Glycolysis-respiration relationships in a neuroblastoma cell line.

    PubMed

    Swerdlow, Russell H; E, Lezi; Aires, Daniel; Lu, Jianghua

    2013-04-01

    Although some reciprocal glycolysis-respiration relationships are well recognized, the relationship between reduced glycolysis flux and mitochondrial respiration has not been critically characterized. We concomitantly measured the extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) of SH-SY5Y neuroblastoma cells under free and restricted glycolysis flux conditions. Under conditions of fixed energy demand ECAR and OCR values showed a reciprocal relationship. In addition to observing an expected Crabtree effect in which increasing glucose availability raised the ECAR and reduced the OCR, a novel reciprocal relationship was documented in which reducing the ECAR via glucose deprivation or glycolysis inhibition increased the OCR. Substituting galactose for glucose, which reduces net glycolysis ATP yield without blocking glycolysis flux, similarly reduced the ECAR and increased the OCR. We further determined how reduced ECAR conditions affect proteins that associate with energy sensing and energy response pathways. ERK phosphorylation, SIRT1, and HIF1a decreased while AKT, p38, and AMPK phosphorylation increased. These data document a novel intracellular glycolysis-respiration effect in which restricting glycolysis flux increases mitochondrial respiration. Since this effect can be used to manipulate cell bioenergetic infrastructures, this particular glycolysis-respiration effect can practically inform the development of new mitochondrial medicine approaches. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Diurnal variations in, and influences on, concentrations of particulate and dissolved arsenic and metals in the mildly alkaline Wallkill River, New Jersey, USA

    USGS Publications Warehouse

    Barringer, J.L.; Wilson, T.P.; Szabo, Z.; Bonin, J.L.; Fischer, J.M.; Smith, N.P.

    2008-01-01

    Diurnal variations in particulate and dissolved As and metal concentrations were observed in mildly alkaline water from a wetlands site on the Wallkill River in northwestern New Jersey. The site, underlain by glacial sediments over dolomite bedrock, is 10 km downstream from a mined area of the Franklin Marble, host to Zn ores, also As and Mn minerals. In mid-September 2005, maxima and minima in dissolved-oxygen-concentration and pH, typically caused by photosynthesis and respiration, occurred at 2000 and 0800 hours. Concentrations of dissolved As (1.52-1.95 ??g/L) peaked at dusk (2000 hours), whereas dissolved Mn and Zn concentrations (76.5-96.9 and 8.55-12.8 ??g/L, respectively) were lowest at dusk and peaked at 1000 hours. These opposing cycles probably reflect sorption and desorption of As (an anion), and Mn and Zn (cations) as pH varied throughout the 24-h period. Doubly-peaked cycles of B, Cl, SO4, and nutrients also were observed; these may result from upstream discharges of septic-system effluent. Both recoverable amd particulate Al, Fe, Mn, and Zn concentrations peaked between 0200 and 0600 hours. The particulate metals cycle, with perturbations at 0400 hours, may be influenced by biological activity. ?? 2007 Springer-Verlag.

  15. Diurnal variations in, and influences on, concentrations of particulate and dissolved arsenic and metals in the mildly alkaline Wallkill River, New Jersey, USA

    NASA Astrophysics Data System (ADS)

    Barringer, Julia L.; Wilson, Timothy P.; Szabo, Zoltan; Bonin, Jennifer L.; Fischer, Jeffrey M.; Smith, Nicholas P.

    2008-01-01

    Diurnal variations in particulate and dissolved As and metal concentrations were observed in mildly alkaline water from a wetlands site on the Wallkill River in northwestern New Jersey. The site, underlain by glacial sediments over dolomite bedrock, is 10 km downstream from a mined area of the Franklin Marble, host to Zn ores, also As and Mn minerals. In mid-September 2005, maxima and minima in dissolved-oxygen-concentration and pH, typically caused by photosynthesis and respiration, occurred at 2000 and 0800 hours. Concentrations of dissolved As (1.52-1.95 μg/L) peaked at dusk (2000 hours), whereas dissolved Mn and Zn concentrations (76.5-96.9 and 8.55-12.8 μg/L, respectively) were lowest at dusk and peaked at 1000 hours. These opposing cycles probably reflect sorption and desorption of As (an anion), and Mn and Zn (cations) as pH varied throughout the 24-h period. Doubly-peaked cycles of B, Cl, SO4, and nutrients also were observed; these may result from upstream discharges of septic-system effluent. Both recoverable amd particulate Al, Fe, Mn, and Zn concentrations peaked between 0200 and 0600 hours. The particulate metals cycle, with perturbations at 0400 hours, may be influenced by biological activity.

  16. Comparing organic versus conventional soil management on soil respiration.

    PubMed

    Mátyás, Bence; Chiluisa Andrade, Maritza Elizabeth; Yandun Chida, Nora Carmen; Taipe Velasco, Carina Maribel; Gavilanes Morales, Denisse Estefania; Miño Montero, Gisella Nicole; Ramirez Cando, Lenin Javier; Lizano Acevedo, Ronnie Xavier

    2018-01-01

    Soil management has great potential to affect soil respiration. In this study, we investigated the effects of organic versus conventional soil management on soil respiration.  We measured the main soil physical-chemical properties from conventional and organic managed soil in Ecuador. Soil respiration was determined using alkaline absorption according to Witkamp.  Soil properties such as organic matter, nitrogen, and humidity, were comparable between conventional and organic soils in the present study, and in a further analysis there was no statically significant correlation with soil respiration. Therefore, even though organic farmers tend to apply more organic material to their fields, but this did not result in a significantly higher CO2 production in their soils in the present study.

  17. Comparing organic versus conventional soil management on soil respiration

    PubMed Central

    Mátyás, Bence; Chiluisa Andrade, Maritza Elizabeth; Yandun Chida, Nora Carmen; Taipe Velasco, Carina Maribel; Gavilanes Morales, Denisse Estefania; Miño Montero, Gisella Nicole; Ramirez Cando, Lenin Javier; Lizano Acevedo, Ronnie Xavier

    2018-01-01

    Soil management has great potential to affect soil respiration. In this study, we investigated the effects of organic versus conventional soil management on soil respiration.  We measured the main soil physical-chemical properties from conventional and organic managed soil in Ecuador. Soil respiration was determined using alkaline absorption according to Witkamp.  Soil properties such as organic matter, nitrogen, and humidity, were comparable between conventional and organic soils in the present study, and in a further analysis there was no statically significant correlation with soil respiration. Therefore, even though organic farmers tend to apply more organic material to their fields, but this did not result in a significantly higher CO2 production in their soils in the present study. PMID:29623193

  18. 30 CFR 70.300 - Respiratory equipment; respirable dust.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Respiratory equipment; respirable dust. 70.300... SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES Respiratory Equipment § 70.300 Respiratory equipment; respirable dust. Respiratory equipment approved by NIOSH under 42 CFR part 84 shall be...

  19. 30 CFR 70.300 - Respiratory equipment; respirable dust.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Respiratory equipment; respirable dust. 70.300... SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES Respiratory Equipment § 70.300 Respiratory equipment; respirable dust. Respiratory equipment approved by NIOSH under 42 CFR part 84 shall be...

  20. 30 CFR 70.300 - Respiratory equipment; respirable dust.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Respiratory equipment; respirable dust. 70.300... SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES Respiratory Equipment § 70.300 Respiratory equipment; respirable dust. Respiratory equipment approved by NIOSH under 42 CFR part 84 shall be...

  1. 30 CFR 70.300 - Respiratory equipment; respirable dust.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Respiratory equipment; respirable dust. 70.300... SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES Respiratory Equipment § 70.300 Respiratory equipment; respirable dust. Respiratory equipment approved by NIOSH under 42 CFR part 84 shall be...

  2. 30 CFR 70.300 - Respiratory equipment; respirable dust.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Respiratory equipment; respirable dust. 70.300... SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES Respiratory Equipment § 70.300 Respiratory equipment; respirable dust. Respiratory equipment approved by NIOSH under 42 CFR part 84 shall be...

  3. 21 CFR 892.1970 - Radiographic ECG/respirator synchronizer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic ECG/respirator synchronizer. 892.1970 Section 892.1970 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1970 Radiographic ECG/respirator...

  4. Control of denitrification in a septage-treating artificial wetland: the dual role of particulate organic carbon.

    PubMed

    Hamersley, M Robert; Howes, Brian L

    2002-10-01

    We examined the factors controlling organic carbon (C) cycling and its control of nitrogen (N) removal via denitrification in an aerated artificial wetland treating highly concentrated wastewater to nutrient-removal standards. Processing of organic material by the septage-treating wetland affected the biological reactivity (half-life, or t1/2) of organic C pools through microbial degradation and gravity fractionation of the influent septage. Primary sedimentation fractionated the initial septage material (t1/2 = 8.4d) into recalcitrant waste solids (t1/2 = 16.7d) and highly labile supernatant (t1/2 = 5.0d), allowing this reactive fraction to be further degraded during treatment in aerobic wetland tanks until a less labile material (t1/2 = 7.3d) remained. Organic C contributions from in situ fixation by nitrifying bacteria or algae in these tanks were small, about 1% of the C degradation rate. In the aerated tanks, denitrification was correlated with particulate organic C loading rates, although the average C required (0.35 mg C L(-1)h(-1)) to support denitrification was only 12% of the total C respiration rate (2.9 mg C L(-1)h(-1)). Additions of plant litter (2.5g C L(-1)) to the aerated tanks under normal operating conditions doubled denitrification rates to 0.58 mg N L(-1)h(-1), and reduced effluent nitrate levels by half, from 12.7 to 6.4 mg N L(-1). However, C degradation within the plant litter (0.15mg C L(-1)h(-1)) was sufficient to have accounted for only 35% of the additional denitrification. Evidence from laboratory and full-scale plant litter additions as well as process monitoring indicates that the stimulation of denitrification is due to the respiration-driven formation of anaerobic microsites within particulate organic C. In this aerated highly C-loaded septage-treating wetland, anaerobic microsite, rather than C substrate availability limits denitrification.

  5. Controls on Ecosystem and Root Respiration in an Alaskan Peatland

    NASA Astrophysics Data System (ADS)

    McConnell, N. A.; McGuire, A. D.; Harden, J. W.; Kane, E. S.; Turetsky, M. R.

    2010-12-01

    Boreal ecosystems cover 14% of the vegetated surface on earth and account for 25-30% of the world’s soil carbon (C), mainly due to large carbon stocks in deep peat and frozen soil layers. While peatlands have served as historical sinks of carbon, global climate change may trigger re-release of C to the atmosphere and may turn these ecosystems into net C sources. Rates of C release from a peatland are determined by regional climate and local biotic and abiotic factors such as vegetation cover, thaw depth, and peat thickness. Soil CO2 fluxes are driven by both autotrophic (plant) respiration and heterotrophic (microbial) respiration. Thus, changes in plant and microbial activity in the soil will impact CO2 emissions from peatlands. In this study, we explored environmental and vegetation controls on ecosystem respiration and root respiration in a variety of wetland sites. The study was conducted at the Alaskan Peatland Experiment (APEX; www.uoguelph.ca/APEX) sites in the Bonanza Creek Experimental Forest located 35 km southwest of Fairbanks Alaska. We measured ecosystem respiration, root respiration, and monitored a suite of environmental variables along a vegetation and soil moisture gradient including a black spruce stand with permafrost, a shrubby site with permafrost, a tussock grass site, and a herbaceous open rich fen. Within the rich fen, we have been conducting water table manipulations including a control, lowered, and raised water table treatment. In each of our sites, we measured total ecosystem respiration using static chambers and root respiration by harvesting roots from the uppermost 20 cm and placing them in a root cuvette to obtain a root flux. Ecosystem respiration (ER) on a μmol/m2/sec basis varied across sites. Water table was a significant predictor of ER at the lowered manipulation site and temperature was a strong predictor at the control site in the rich fen. Water table and temperature were both significant predictors of ER at the raised

  6. Airborne particulate discriminator

    DOEpatents

    Creek, Kathryn Louise [San Diego, CA; Castro, Alonso [Santa Fe, NM; Gray, Perry Clayton [Los Alamos, NM

    2009-08-11

    A method and apparatus for rapid and accurate detection and discrimination of biological, radiological, and chemical particles in air. A suspect aerosol of the target particulates is treated with a taggant aerosol of ultrafine particulates. Coagulation of the taggant and target particles causes a change in fluorescent properties of the cloud, providing an indication of the presence of the target.

  7. Insulin resistance in HIV-infected youth is associated with decreased mitochondrial respiration.

    PubMed

    Takemoto, Jody K; Miller, Tracie L; Wang, Jiajia; Jacobson, Denise L; Geffner, Mitchell E; Van Dyke, Russell B; Gerschenson, Mariana

    2017-01-02

    To identify relationships between insulin resistance (IR) and mitochondrial respiration in perinatally HIV-infected youth. Case-control study. Mitochondrial respiration was assessed in perinatally HIV-infected youth in Tanner stages 2-5, 25 youth with IR (IR+) and 50 without IR (IR-) who were enrolled in the Pediatric HIV/AIDS Cohort Study. IR was defined as a homeostatic model of assessment for IR value at least 4.0. A novel, high-throughput oximetry method was used to evaluate cellular respiration in peripheral blood mononuclear cells. Unadjusted and adjusted differences in mitochondrial respiration markers between IR+ and IR- were evaluated, as were correlations between mitochondrial respiration markers and biochemical measurements. IR+ and IR- youth were similar on age, sex, and race/ethnicity. Mean age was 16.5 and 15.6 years in IR+ and IR-, respectively. The IR+ group had significantly higher mean BMI and metabolic analytes (fasting glucose, insulin, cholesterol, triglycerides, and venous lactate and pyruvate) compared with the IR-. Mitochondrial respiration markers were, on average, lower in the IR+ compared with IR-, including basal respiration (417.5 vs. 597.5 pmol, P = 0.074), ATP production (11 513 vs. 15 202 pmol, P = 0.078), proton leak (584.6 vs. 790.0 pmol, P = 0.033), maximal respiration (1815 vs. 2399 pmol, P = 0.025), and spare respiration capacity (1162 vs. 2017 pmol, P = 0.032). Nonmitochondrial respiration did not differ by IR status. The results did not change when adjusted for age. HIV-infected youth with IR have lower mitochondrial respiration markers when compared to youth without IR. Disordered mitochondrial respiration may be a potential mechanism for IR in this population.

  8. Void/particulate detector

    DOEpatents

    Claytor, Thomas N.; Karplus, Henry B.

    1985-01-01

    Voids and particulates are detected in a flowing stream of fluid contained in a pipe by a detector which includes three transducers spaced about the pipe. A first transducer at a first location on the pipe transmits an ultrasonic signal into the stream. A second transducer detects the through-transmission of the signal at a second location and a third transducer at a third location upstream from the first location detects the back-scattering of the signal from any voids or particulates. To differentiate between voids and particulates a fourth transducer is positioned at a fourth location which is also upstream from the first location. The back-scattered signals are normalized with the through-transmission signal to minimize temperature fluctuations.

  9. Soil Respiration and Student Inquiry: A Perfect Match

    ERIC Educational Resources Information Center

    Hoyt, Catherine Marie; Wallenstein, Matthew David

    2011-01-01

    This activity explores the cycling of carbon between the atmosphere (primarily as CO[subscript 2]) and biomass in plants, animals, and microscopic organisms. Students design soil respiration experiments using a protocol that resembles current practice in soil ecology. Three methods for measuring soil respiration are presented. Student-derived…

  10. 30 CFR 72.700 - Respiratory equipment; respirable dust.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Respiratory equipment; respirable dust. 72.700... SAFETY AND HEALTH HEALTH STANDARDS FOR COAL MINES Miscellaneous § 72.700 Respiratory equipment; respirable dust. (a) Respiratory equipment approved by NIOSH under 42 CFR part 84 shall be made available to...

  11. Boreal and temperate trees show strong acclimation of respiration to warming.

    PubMed

    Reich, Peter B; Sendall, Kerrie M; Stefanski, Artur; Wei, Xiaorong; Rich, Roy L; Montgomery, Rebecca A

    2016-03-31

    Plant respiration results in an annual flux of carbon dioxide (CO2) to the atmosphere that is six times as large as that due to the emissions from fossil fuel burning, so changes in either will impact future climate. As plant respiration responds positively to temperature, a warming world may result in additional respiratory CO2 release, and hence further atmospheric warming. Plant respiration can acclimate to altered temperatures, however, weakening the positive feedback of plant respiration to rising global air temperature, but a lack of evidence on long-term (weeks to years) acclimation to climate warming in field settings currently hinders realistic predictions of respiratory release of CO2 under future climatic conditions. Here we demonstrate strong acclimation of leaf respiration to both experimental warming and seasonal temperature variation for juveniles of ten North American tree species growing for several years in forest conditions. Plants grown and measured at 3.4 °C above ambient temperature increased leaf respiration by an average of 5% compared to plants grown and measured at ambient temperature; without acclimation, these increases would have been 23%. Thus, acclimation eliminated 80% of the expected increase in leaf respiration of non-acclimated plants. Acclimation of leaf respiration per degree temperature change was similar for experimental warming and seasonal temperature variation. Moreover, the observed increase in leaf respiration per degree increase in temperature was less than half as large as the average reported for previous studies, which were conducted largely over shorter time scales in laboratory settings. If such dampening effects of leaf thermal acclimation occur generally, the increase in respiration rates of terrestrial plants in response to climate warming may be less than predicted, and thus may not raise atmospheric CO2 concentrations as much as anticipated.

  12. Global Soil Respiration: Interaction with Environmental Variables and Response to Climate Change

    NASA Astrophysics Data System (ADS)

    Jian, J.; Steele, M.

    2016-12-01

    Background, methods, objectivesTerrestrial ecosystems take up around 1.7 Pg C per year; however, the role of terrestrial ecosystems as a carbon sink may change to carbon source by 2050, as a result of positive feedback of soil respiration response to global warming. Nevertheless, limited evidence shows that soil carbon is decreasing and the role of terrestrial ecosystems is changing under warming. One possibility is the positive feedback may slow due to the acclimation of soil respiration as a result of decreasing temperature sensitivity (Q10) with warming. To verify and quantify the uncertainty in soil carbon cycling and feedbacks to climate change, we assembled soil respiration observations from 1961 to 2014 from 724 publications into a monthly global soil respiration database (MSRDB), which included 13482 soil respiration measurements together with 38 other ancillary measurements from 538 sites. Using this database we examined macroscale variation in the relationship between soil respiration and air temperature, precipitation, leaf area index and soil properties. We also quantified global soil respiration, the sources of uncertainty, and its feedback to warming based on climate region-oriented models with variant Q10function. Results and ConclusionsOur results showed substantial heterogeneity in the relationship between soil respiration and environmental factors across different climate regions. For example, soil respiration was strongly related to vegetation (via leaf area index) in colder regions, but not in tropical region. Only in tropical and arid regions did soil properties explain any variation in soil respiration. Global annual mean soil respiration from 1961 to 2014 was estimated to be 72.41 Pg C yr-1 based on monthly global soil respiration database, 25 Pg lower than estimated based on yearly soil respiration database. By using the variable Q10 models, we estimated that global soil respiration increased at a rate of 0.03 Pg C yr-1 from 1961 to 2014

  13. Alterations in Respiration Rate and Glycolytic Intermediates in Wounded Sugarbeet Roots

    USDA-ARS?s Scientific Manuscript database

    Wounding of sugarbeet roots causes an increase in respiration rate, which contributes to postharvest sucrose losses. Although respiration is estimated to cause 60 to 80% of postharvest sucrose losses, the mechanisms that regulate respiration rate in wounded sugarbeet roots are not well know. To id...

  14. 30 CFR 71.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere... 20%, Therefore, the average concentration of respirable dust in the mine atmosphere associated with...

  15. 30 CFR 71.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere... 20%, Therefore, the average concentration of respirable dust in the mine atmosphere associated with...

  16. 30 CFR 71.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere... 20%, Therefore, the average concentration of respirable dust in the mine atmosphere associated with...

  17. 30 CFR 71.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere... 20%, Therefore, the average concentration of respirable dust in the mine atmosphere associated with...

  18. 30 CFR 71.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere... 20%, Therefore, the average concentration of respirable dust in the mine atmosphere associated with...

  19. Silicosis: Learn the Facts!

    MedlinePlus

    ... during water tank construction. He wore a charcoal filter respirator while sandblasting, but it was the wrong ... properly fitted and selected respirator (e.g. particulate filter or airline supplied air respirator) designated for protection ...

  20. Bioturbation enhances the aerobic respiration of lake sediments in warming lakes.

    PubMed

    Baranov, Viktor; Lewandowski, Jörg; Krause, Stefan

    2016-08-01

    While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m(2) was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming. © 2016 The Authors.

  1. Bioturbation enhances the aerobic respiration of lake sediments in warming lakes

    PubMed Central

    Krause, Stefan

    2016-01-01

    While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m2 was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming. PMID:27484649

  2. Evaluation of the impact of storm event inputs on levels of gross primary production and respiration in a drinking water reservoir

    NASA Astrophysics Data System (ADS)

    Samal, N. R.; Pierson, D. C.; Staehr, P. A.; Pradhanang, S. M.; Smith, D. G.

    2013-12-01

    Episodic inputs of dissolved and particulate material during storm events can have important effects on lake and reservoir ecosystem function and also impact reservoir drinking water quality. We evaluate the impacts of storm events using vertical profiles of temperature, dissolved oxygen, turbidity, conductivity and chlorophyll automatically collected at 6 hour intervals in Ashokan Reservoir, which is a part of the New York City drinking water supply. Storm driven inputs to the reservoir periodically result in large input of suspended sediments that result in reservoir turbidity levels exceeding 25 NTU, and substantial reductions in the euphotic depth. Dissolved materials associated with these same storms would be expected to stimulate bacterial production. This study involves the use of a conceptual model to calculate depth specific estimates of gross primary production (GPP) and ecosystem respiration (R) using three years of data that included 777 events that increased reservoir turbidity levels to over 25 NTU. Using data from before, during and after storm events, we examine how the balance between GPP and R is influenced by storm related increases in turbidity and dissolved organic matter, which would in turn influence light attenuation and bacterial production. Key words: metabolism, primary production, GPP, respiration, euphotic depth, storm event, reservoir

  3. BOREAS TE-2 Root Respiration Data

    NASA Technical Reports Server (NTRS)

    Ryan, Michael G.; Lavigne, Michael; Hall, Forrest G. (Editor); Papagno, Andrea (Editor)

    2000-01-01

    The BOREAS TE-2 team collected several data sets in support of its efforts to characterize and interpret information on the respiration of the foliage, roots, and wood of boreal vegetation. This data set includes means of tree root respiration measurements on roots having diameters ranging from 0 to 2 mm conducted in the NSA during the growing season of 1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  4. Measuring priming using 14C of respired CO2: effects on respiration source pools and interactions with warming

    NASA Astrophysics Data System (ADS)

    Hopkins, F. M.; Trumbore, S.

    2011-12-01

    The role of substrate availability on soil carbon turnover is a critical unknown in predicting future soil carbon stocks. Substrate composition and availability can be altered by land cover change, warming, and nitrogen deposition, which can in turn affect soil carbon stocks through the priming effect. In particular, little is understood about the interaction between warming and changing substrate concentration. We examined the interactions between global change factors and the priming effect using sucrose addition to incubations of soils from two forest Free Air CO2 Enrichment (FACE) sites (Duke and Aspen). In addition to the in situ global change manipulations conducted at these sites, the CO2 fertilization procedure over the decade-long experiment labeled soil carbon pools with fossil-derived carbon (depleted in 14C relative to the background isotope content of soil carbon), allowing us to determine the effect of priming on respiration of soil carbon substrates of different ages. Thus, we used the carbon-13 signature of sucrose-derived CO2 to account for losses of substrate C, and the carbon-14 signature to partition fluxes of soil-derived CO2 between pre-FACE (> 10 y) and FACE derived (< 10 y) carbon sources. At both sites, we observed a positive priming effect-an increase in the rate of soil carbon derived respiration due to sucrose addition. However, the effect of substrate addition on respiratory source pools, as measured by 14C of respiration, varied greatly. At Duke FACE, we observed an increase in 14C content of CO2 of primed soil carbon, whereas at Aspen, we observed no difference. The amount of CO2 released by priming increased with temperature, but was proportionally similar to the amount of increase in basal respiration rates (no differences in Q10). At Duke, both warming and priming served to increase the 14C of respiration, whereas only warming changed 14C of respiration at Aspen. Despite similar overall carbon stocks, differences in the source of

  5. Changes in mitochondrial respiration in the human placenta over gestation.

    PubMed

    Holland, Olivia J; Hickey, Anthony J R; Alvsaker, Anna; Moran, Stephanie; Hedges, Christopher; Chamley, Lawrence W; Perkins, Anthony V

    2017-09-01

    Placental mitochondria are subjected to micro-environmental changes throughout gestation, in particular large variations in oxygen. How placental mitochondrial respiration adapts to changing oxygen concentrations remains unexplored. Additionally, placental tissue is often studied in culture; however, the effect of culture on placental mitochondria is unclear. Placental tissue was obtained from first trimester and term (laboured and non-laboured) pregnancies, and selectively permeabilized to access mitochondria. Respirometry was used to compare respiration states and substrate use in mitochondria. Additionally, explants of placental tissue were cultured for four, 12, 24, 48, or 96 h and respiration measured. Mitochondrial respiration decreased at 11 weeks compared to earlier gestations (p = 0.05-0.001), and mitochondrial content increased at 12-13 weeks compared to 7-10 weeks (p = 0.042). In term placentae, oxidative phosphorylation (OXPHOS) through mitochondrial complex IV (p < 0.001), the relative proportion of OXPHOS CI (p < 0.001), the total capacity of the respiratory system (p = 0.003), and mitochondrial content (p < 0.001) were higher compared to first trimester. Respiration was increased (p ≤ 0.006-0.001) in laboured compared to non-laboured placenta. After four hours of culture, respiration was depressed compared to fresh tissue from the same placenta and continued to decline with time in culture. Markers of apoptosis were increased, while markers of autophagy, mitochondrial biogenesis, and mitochondrial membrane potential were decreased after four hours of culture. Respiration and mitochondrial content alter over gestation/with labour. Decreased respiration at 11 weeks and increased mitochondrial content at 12-13 weeks may relate to onset of maternal blood flow, and increased respiration as a result of labour may be an adaptation to ischaemia-reperfusion. At term, mitochondria were more susceptible to changes in respiratory function

  6. Interpreting diel hysteresis between soil respiration and temperature

    Treesearch

    C. Phillips; N. Nickerson; D. Risk; B.J. Bond

    2011-01-01

    Increasing use of automated soil respiration chambers in recent years has demonstrated complex diel relationships between soil respiration and temperature that are not apparent from less frequent measurements. Soil surface flux is often lagged from soil temperature by several hours, which results in semielliptical hysteresis loops when surface flux is plotted as a...

  7. Supporting aspartate biosynthesis is an essential function of respiration in proliferating cells

    PubMed Central

    Sullivan, Lucas B.; Gui, Dan Y.; Hosios, Aaron M.; Bush, Lauren N.; Freinkman, Elizaveta; Vander Heiden, Matthew G.

    2015-01-01

    Summary Mitochondrial respiration is important for cell proliferation, however the specific metabolic requirements fulfilled by respiration to support proliferation have not been defined. Here we show that a major role of respiration in proliferating cells is to provide electron acceptors for aspartate synthesis. This finding is consistent with the observation that cells lacking a functional respiratory chain are auxotrophic for pyruvate, which serves as an exogenous electron acceptor. Further, the pyruvate requirement can be fulfilled with an alternative electron acceptor, alpha-ketobutyrate, which provides cells neither carbon nor ATP. Alpha-ketobutyrate restores proliferation when respiration is inhibited, suggesting that an alternative electron acceptor can substitute for respiration to support proliferation. We find that electron acceptors are limiting for producing aspartate, and supplying aspartate enables proliferation of respiration deficient cells in the absence of exogenous electron acceptors. Together, these data argue a major function of respiration in proliferating cells is to support aspartate synthesis. PMID:26232225

  8. Supporting Aspartate Biosynthesis Is an Essential Function of Respiration in Proliferating Cells.

    PubMed

    Sullivan, Lucas B; Gui, Dan Y; Hosios, Aaron M; Bush, Lauren N; Freinkman, Elizaveta; Vander Heiden, Matthew G

    2015-07-30

    Mitochondrial respiration is important for cell proliferation; however, the specific metabolic requirements fulfilled by respiration to support proliferation have not been defined. Here, we show that a major role of respiration in proliferating cells is to provide electron acceptors for aspartate synthesis. This finding is consistent with the observation that cells lacking a functional respiratory chain are auxotrophic for pyruvate, which serves as an exogenous electron acceptor. Further, the pyruvate requirement can be fulfilled with an alternative electron acceptor, alpha-ketobutyrate, which provides cells neither carbon nor ATP. Alpha-ketobutyrate restores proliferation when respiration is inhibited, suggesting that an alternative electron acceptor can substitute for respiration to support proliferation. We find that electron acceptors are limiting for producing aspartate, and supplying aspartate enables proliferation of respiration deficient cells in the absence of exogenous electron acceptors. Together, these data argue a major function of respiration in proliferating cells is to support aspartate synthesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Chemical speciation of respirable suspended particulate matter during a major firework festival in India.

    PubMed

    Sarkar, Sayantan; Khillare, Pandit S; Jyethi, Darpa S; Hasan, Amreen; Parween, Musarrat

    2010-12-15

    Ambient respirable particles (PM ≤ 10 μm, denoted by PM(10)) were characterized with respect to 20 elements, 16 polycyclic aromatic hydrocarbons (PAHs), elemental and organic carbon (EC and OC) during a major firework event-the "Diwali" festival in Delhi, India. The event recorded extremely high 24-h PM(10) levels (317.2-616.8 μg m(-3), 6-12 times the WHO standard) and massive loadings of Ba (16.8 μg m(-3), mean value), K (46.8 μg m(-3)), Mg (21.3 μg m(-3)), Al (38.4 μg m(-3)) and EC (40.5 μg m(-3)). Elemental concentrations as high as these have not been reported previously for any firework episode. Concentrations of Ba, K, Sr, Mg, Na, S, Al, Cl, Mn, Ca and EC were higher by factors of 264, 18, 15, 5.8, 5, 4, 3.2, 3, 2.7, 1.6 and 4.3, respectively, on Diwali as compared to background values. It was estimated that firework aerosol contributed 23-33% to ambient PM(10) on Diwali. OC levels peaked in the post-Diwali samples, perhaps owing to secondary transformation processes. Atmospheric PAHs were not sourced from fireworks; instead, they correlated well with changes in traffic patterns indicating their primary source in vehicular emissions. Overall, the pollutant cocktail generated by the Diwali fireworks could be best represented with Ba, K and Sr as tracers. It was also found that chronic exposure to Diwali pollution is likely to cause at least a 2% increase in non-carcinogenic hazard index (HI) associated with Al, Mn and Ba in the exposed population. Copyright © 2010 Elsevier B.V. All rights reserved.

  10. Respirable concrete dust--silicosis hazard in the construction industry.

    PubMed

    Linch, Kenneth D

    2002-03-01

    Concrete is an extremely important part of the infrastructure of modern life and must be replaced as it ages. Many of the methods of removing, repairing, or altering existing concrete structures have the potential for producing vast quantities of respirable dust. Since crystalline silica in the form of quartz is a major component of concrete, airborne respirable quartz dust may be produced during construction work involving the disturbance of concrete, thereby producing a silicosis hazard for exposed workers. Silicosis is a debilitating and sometimes fatal lung disease resulting from breathing microscopic particles of crystalline silica. Between 1992 and 1998, the National Institute for Occupational Safety and Health (NIOSH) made visits to construction projects where concrete was being mechanically disturbed in order to obtain data concerning respirable crystalline silica dust exposures. The construction activities studied included: abrasive blasting, concrete pavement sawing and drilling, and asphalt/concrete milling. Air samples of respirable dust were obtained using 10-mm nylon cyclone pre-separators, 37-mm polyvinyl chloride (PVC) filters, and constant-flow pumps calibrated at 1.7 L/min. In addition, high-volume respirable dust samples were obtained on 37-mm PVC filters using 1/2" metal cyclones (Sensidyne model 18) and constant-flow pumps calibrated at 9.0 L/min. Air sample analysis included total weight gain by gravimetric analysis according to NIOSH Analytical Method 600 and respirable crystalline silica (quartz and cristobalite) using x-ray diffraction, as per NIOSH Analytical Method 7500. For abrasive blasting of concrete structures, the respirable crystalline silica (quartz) concentration ranged up to 14.0 mg/m3 for a 96-minute sample resulting in an eight-hour time-weighted average (TWA) of 2.8 mg/m3. For drilling concrete highway pavement the respirable quartz concentrations ranged up to 4.4 mg/m3 for a 358-minute sample, resulting in an eight-hour TWA

  11. Fatal injuries in the United States involving respirators, 1984-1995.

    PubMed

    Suruda, Anthony; Milliken, William; Stephenson, Dale; Sesek, Richard

    2003-04-01

    There is little published information concerning the epidemiology of fatal injuries involving respiratory protection. We compiled a case series from U.S. Occupational Safety and Health Administration investigation reports from 1984 through 1995. For the 12-year period there were 41 incidents resulting in 45 deaths due to asphyxiation or chemical poisoning while wearing a respirator. There were 23 deaths related to airline respirators, 17 deaths involving use of negative pressure (air purifying) respirators, and 5 deaths involving self-contained breathing apparatus. Among the 23 deaths involving airline respirators, 15 were associated with compatible connection couplings for breathable air and inert gases. Three workers with beards died who wore tight-fitting respirators in an atmosphere that was immediately dangerous to life and health. Most of the fatalities involved regulatory and procedural violations, and would have been prevented by proper training and compliance with existing regulations. The information concerning the victims was limited but it did not appear that medical screening would have prevented any of the deaths.

  12. Effect of test exercises and mask donning on measured respirator fit.

    PubMed

    Crutchfield, C D; Fairbank, E O; Greenstein, S L

    1999-12-01

    Quantitative respirator fit test protocols are typically defined by a series of fit test exercises. A rationale for the protocols that have been developed is generally not available. There also is little information available that describes the effect or effectiveness of the fit test exercises currently specified in respiratory protection standards. This study was designed to assess the relative impact of fit test exercises and mask donning on respirator fit as measured by a controlled negative pressure and an ambient aerosol fit test system. Multiple donnings of two different sizes of identical respirator models by each of 14 test subjects showed that donning affects respirator fit to a greater degree than fit test exercises. Currently specified fit test protocols emphasize test exercises, and the determination of fit is based on a single mask donning. A rationale for a modified fit test protocol based on fewer, more targeted test exercises and multiple mask donnings is presented. The modified protocol identified inadequately fitting respirators as effectively as the currently specified Occupational Safety and Health Administration (OSHA) quantitative fit test protocol. The controlled negative pressure system measured significantly (p < 0.0001) more respirator leakage than the ambient aerosol fit test system. The bend over fit test exercise was found to be predictive of poor respirator fit by both fit test systems. For the better fitting respirators, only the talking exercise generated aerosol fit factors that were significantly lower (p < 0.0001) than corresponding donning fit factors.

  13. Tai Chi training reduced coupling between respiration and postural control.

    PubMed

    Holmes, Matthew L; Manor, Brad; Hsieh, Wan-hsin; Hu, Kun; Lipsitz, Lewis A; Li, Li

    2016-01-01

    In order to maintain stable upright stance, the postural control system must account for the continuous perturbations to the body's center-of-mass including those caused by spontaneous respiration. Both aging and disease increase "posturo-respiratory synchronization;" which reflects the degree to which respiration affects postural sway fluctuations over time. Tai Chi training emphasizes the coordination of respiration and bodily movements and may therefore optimize the functional interaction between these two systems. The purpose of the project was to examine the effect of Tai Chi training on the interaction between respiration and postural control in older adults. We hypothesized that Tai Chi training would improve the ability of the postural control system to compensate for respiratory perturbations and thus, reduce posturo-respiratory synchronization. Participants were recruited from supportive housing facilities and randomized to a 12-week Tai Chi intervention (n=28; 86 ± 5 yrs) or educational-control program (n=34, 85 ± 6 yrs). Standing postural sway and respiration were simultaneously recorded with a force plate and respiratory belt under eyes-open and eyes-closed conditions. Posturo-respiratory synchronization was determined by quantifying the variation of the phase relationship between the dominant oscillatory mode of respiration and corresponding oscillations within postural sway. Groups were similar in age, gender distribution, height, body mass, and intervention compliance. Neither intervention altered average sway speed, sway magnitude or respiratory rate. As compared to the education-control group, however, Tai Chi training reduced posturo-respiratory synchronization when standing with eyes open or closed (p<0.001). Tai Chi training did not affect traditional parameters of standing postural control or respiration, yet reduced the coupling between respiration and postural control. The beneficial effects of Tai Chi training may therefore stem in part

  14. Tai Chi training reduced coupling between respiration and postural control

    PubMed Central

    Holmes, Matthew L; Manor, Brad; Hsieh, Wan-hsin; Hu, Kun; Lipsitz, Lewis A; Li, Li

    2015-01-01

    In order to maintain stable upright stance, the postural control system must account for the continuous perturbations to the body’s center-of-mass including those caused by spontaneous respiration. Both aging and disease increase “posturo-respiratory synchronization;” which reflects the degree to which respiration affects postural sway fluctuations over time. Tai Chi training emphasizes the coordination of respiration and bodily movements and may therefore optimize the functional interaction between these two systems. The purpose of the project was to examine the effect of Tai Chi training on the interaction between respiration and postural control in older adults. We hypothesized that Tai Chi training would improve the ability of the postural control system to compensate for respiratory perturbations and thus, reduce posturo-respiratory synchronization. Participants were recruited from supportive housing facilities and randomized to a 12-week Tai Chi intervention (n=28; 86±5yrs) or educational-control program (n=34, 85±6yrs). Standing postural sway and respiration were simultaneously recorded with a force plate and respiratory belt under eyes-open and eyes-closed conditions. Posturo-respiratory synchronization was determined by quantifying the variation of the phase relationship between the dominant oscillatory mode of respiration and corresponding oscillations within postural sway. Groups were similar in age, gender distribution, height, body mass, and intervention compliance. Neither intervention altered average sway speed, sway magnitude or respiratory rate. As compared to the education-control group, however, Tai Chi training reduced posturo-respiratory synchronization when standing with eyes open or closed (p<0.001). Tai Chi training did not affect traditional parameters of standing postural control or respiration, yet reduced the coupling between respiration and postural control. The beneficial effects of Tai Chi training may therefore stem in part

  15. Small ecosystem engineers as important regulators of lake's sediment respiration.

    NASA Astrophysics Data System (ADS)

    Baranov, Victor; Lewandowski, Joerg; Krause, Stefan; Romeijn, Paul

    2016-04-01

    Although shallow lakes are covering only about 1.5% of the land surface of the Earth, they are responsible for sequestration of carbon amounts similar or even larger than those sequestered in all marine sediments. One of the most important drivers of the carbon sequestration in lakes is sediment respiration. Especially in shallow lakes, bioturbation, i.e. the biogenic reworking of the sediment matrix and the transport of fluids within the sediment, severely impacts on sediment respiration. Widespread freshwater bioturbators such as chironomid larvae (Diptera, Chironomidae) are building tubes in the sediment and actively pump water through their burrows (ventilation). In the present work we study how different organism densities and temperatures (5-30°C) impact on respiration rates. In a microcosm experiment the bioreactive resazurin/resorufin smart tracer system was applied for quantifying the impacts of different densities of Chironomidae (Diptera) larvae (0, 1000, 2000 larvae/m2) on sediment respiration. Tracer transformation rates (and sediment respiration) were correlated with larval densities with highest transformation rates occurring in microcosms with highest larval densities. Respiration differences between defaunated sediment and sediment with 1000 and 2000 larvae per m2 was insignificant at 5 °C, and was progressively increasing with rising temperatures. At 30 °C respiration rates of sediment with 2000 larvae per m2 was 4.8 times higher than those of defaunated sediment. We interpret this as an effect of temperature on larval metabolic and locomotory activity. Furthermore, bacterial communities are benefiting from the combination of the high water temperatures and bioirrigation as bacterial community are able to maintain high metabolic rates due to oxygen supplied by bioirrigation. In the context of global climate change that means that chironomid ecosystem engineering activity will have a profound and increasing impact on lake sediment respiration

  16. Occupational Exposure to Respirable Crystalline Silica. Final rule.

    PubMed

    2016-03-25

    The Occupational Safety and Health Administration (OSHA) is amending its existing standards for occupational exposure to respirable crystalline silica. OSHA has determined that employees exposed to respirable crystalline silica at the previous permissible exposure limits face a significant risk of material impairment to their health. The evidence in the record for this rulemaking indicates that workers exposed to respirable crystalline silica are at increased risk of developing silicosis and other non-malignant respiratory diseases, lung cancer, and kidney disease. This final rule establishes a new permissible exposure limit of 50 micrograms of respirable crystalline silica per cubic meter of air (50 [mu]g/m\\3\\) as an 8-hour time-weighted average in all industries covered by the rule. It also includes other provisions to protect employees, such as requirements for exposure assessment, methods for controlling exposure, respiratory protection, medical surveillance, hazard communication, and recordkeeping. OSHA is issuing two separate standards--one for general industry and maritime, and the other for construction--in order to tailor requirements to the circumstances found in these sectors.

  17. Aerosol penetration through respirator exhalation valves.

    PubMed

    Bellin, P; Hinds, W C

    1990-10-01

    Exhalation valves are a critical component of industrial respirators. They are designed to permit minimal inward leakage of air contaminants during inhalation and provide low resistance during exhalation. Under normal conditions, penetration of aerosol through exhalation valves is minimal. The exhalation valve is, however, a vulnerable component of a respirator and under actual working conditions may become dirty or damaged to the point of causing significant leakage. Aerosol penetration was measured for normal exhalation valves and valves compromised by paint or fine copper wires on the valve seat. Penetration increased with increasing wire diameter. A wire 250 microns in diameter allowed greater than 1% penetration into the mask cavity. Dirt or paint accumulated on the exhalation valve allowed a similar level of penetration. Work rate had little effect on observed penetration. Penetration decreased significantly with increasing aerosol particle size. The amount of material on the valve or valve seat necessary for significant (greater than 0.5%) inward leakage in a half-mask respirator could be readily observed by careful inspection of the exhalation valve and its seat in good lighting conditions.

  18. Escherichia coli attachment to model particulates: The effects of bacterial cell characteristics and particulate properties.

    PubMed

    Liang, Xiao; Liao, Chunyu; Soupir, Michelle L; Jarboe, Laura R; Thompson, Michael L; Dixon, Philip M

    2017-01-01

    E. coli bacteria move in streams freely in a planktonic state or attached to suspended particulates. Attachment is a dynamic process, and the fraction of attached microorganisms is thought to be affected by both bacterial characteristics and particulate properties. In this study, we investigated how the properties of cell surfaces and stream particulates influence attachment. Attachment assays were conducted for 77 E. coli strains and three model particulates (ferrihydrite, Ca-montmorillonite, or corn stover) under environmentally relevant conditions. Surface area, particle size distribution, and total carbon content were determined for each type of particulate. Among the three particulates, attachment fractions to corn stover were significantly larger than the attachments to 2-line ferrihydrite (p-value = 0.0036) and Ca-montmorillonite (p-value = 0.022). Furthermore, attachment to Ca-montmorillonite and corn stover was successfully modeled by a Generalized Additive Model (GAM) using cell characteristics as predictor variables. The natural logarithm of the net charge on the bacterial surface had a significant, positive, and linear impact on the attachment of E. coli bacteria to Ca-montmorillonite (p-value = 0.013), but it did not significantly impact the attachment to corn stover (p-value = 0.36). The large diversities in cell characteristics among 77 E. coli strains, particulate properties, and attachment fractions clearly demonstrated the inadequacy of using a static parameter or linear coefficient to predict the attachment behavior of E. coli in stream water quality models.

  19. 30 CFR 90.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... quartz is present. When the respirable dust in the mine atmosphere of the active workings to which a Part... average concentration of respirable dust in the mine atmosphere during each shift to which a Part 90 miner...%. Therefore, the average concentration of respirable dust in the mine atmosphere associated with that Part 90...

  20. 30 CFR 90.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... quartz is present. When the respirable dust in the mine atmosphere of the active workings to which a Part... average concentration of respirable dust in the mine atmosphere during each shift to which a Part 90 miner...%. Therefore, the average concentration of respirable dust in the mine atmosphere associated with that Part 90...

  1. 30 CFR 90.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... quartz is present. When the respirable dust in the mine atmosphere of the active workings to which a Part... average concentration of respirable dust in the mine atmosphere during each shift to which a Part 90 miner...%. Therefore, the average concentration of respirable dust in the mine atmosphere associated with that Part 90...

  2. 30 CFR 90.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... quartz is present. When the respirable dust in the mine atmosphere of the active workings to which a Part... average concentration of respirable dust in the mine atmosphere during each shift to which a Part 90 miner...%. Therefore, the average concentration of respirable dust in the mine atmosphere associated with that Part 90...

  3. 30 CFR 90.101 - Respirable dust standard when quartz is present.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... quartz is present. When the respirable dust in the mine atmosphere of the active workings to which a Part... average concentration of respirable dust in the mine atmosphere during each shift to which a Part 90 miner...%. Therefore, the average concentration of respirable dust in the mine atmosphere associated with that Part 90...

  4. Differential soil respiration responses to changing hydrologic regimes

    Treesearch

    Vincent J. Pacific; Brian L. McGlynn; Diego A. Riveros-Iregui; Howard E. Epstein; Daniel L. Welsch

    2009-01-01

    Soil respiration is tightly coupled to the hydrologic cycle (i.e., snowmelt and precipitation timing and magnitude). We examined riparian and hillslope soil respiration across a wet (2005) and a dry (2006) growing season in a subalpine catchment. When comparing the riparian zones, cumulative CO2 efflux was 33% higher, and peak efflux occurred 17 days earlier during the...

  5. Targeting mitochondrial respiration as a therapeutic strategy for cervical cancer.

    PubMed

    Tian, Shenglan; Chen, Heng; Tan, Wei

    2018-05-23

    Targeting mitochondrial respiration has been documented as an effective therapeutic strategy in cancer. However, the impact of mitochondrial respiration inhibition on cervical cancer cells are not well elucidated. Using a panel of cervical cancer cell lines, we show that an existing drug atovaquone is active against the cervical cancer cells with high profiling of mitochondrial biogenesis. Atovaquone inhibited proliferation and induced apoptosis with varying efficacy among cervical cancer cell lines regardless of HPV infection, cellular origin and their sensitivity to paclitaxel. We further demonstrated that atovaquone acts on cervical cancer cells via inhibiting mitochondrial respiration. In particular, atovaquone specifically inhibited mitochondrial complex III but not I, II or IV activity, leading to respiration inhibition and energy crisis. Importantly, we found that the different sensitivity of cervical cancer cell lines to atovaquone were due to their differential level of mitochondrial biogenesis and dependency to mitochondrial respiration. In addition, we demonstrated that the in vitro observations were translatable to in vivo cervical cancer xenograft mouse model. Our findings suggest that the mitochondrial biogenesis varies among patients with cervical cancer. Our work also suggests that atovaquone is a useful addition to cervical cancer treatment, particularly to those with high dependency on mitochondrial respiration. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. Respirators, internal dose, and Oyster Creek

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Michal, R.

    1996-06-01

    This article looks at the experience of Oyster Creek in relaxing the requirements for the use of respirators in all facets of plant maintenance, on the overall dose received by plant maintenance personnel. For Roger Shaw, director of radiological controls for three years at GPU Nuclear Corporation`s Oyster Creek nuclear plant the correct dose balance is determined on a job-by-job basis: Does the job require a respirator, which is an effective means of decreasing worker inhalation of airborne radioactive particles? Will wearing a respirator slow down a worker, consequently increasing whole body radiation exposure by prolonging the time spent inmore » fields of high external radiation? How does respiratory protection affect worker safety and to what degree? While changes to the Nuclear Regulatory Commission`s 10CFR20 have updated the radiation protection requirements for the nuclear industry, certain of the revisions have been directed specifically at reducing worker dose, Shaw said. {open_quotes}It basically delineates that dose is dose,{close_quotes} Shaw said, {open_quotes}regardless of whether it is acquired externally or internally.{close_quotes} The revision of Part 20 changed the industry`s attitude toward internal dose, which had always been viewed negatively. {open_quotes}Internal dose was always seen as preventable by wearing respirators and by using engineering techniques such as ventilation control and decontamination,{close_quotes} Shaw said, {open_quotes}whereas external dose, although reduced where practical, was seen as a fact of the job.{close_quotes}« less

  7. Soil respiration across a permafrost transition zone: spatial structure and environmental correlates

    NASA Astrophysics Data System (ADS)

    Stegen, James C.; Anderson, Carolyn G.; Bond-Lamberty, Ben; Crump, Alex R.; Chen, Xingyuan; Hess, Nancy

    2017-09-01

    Soil respiration is a key ecosystem function whereby shifts in respiration rates can shift systems from carbon sinks to sources. Soil respiration in permafrost-associated systems is particularly important given climate change driven permafrost thaw that leads to significant uncertainty in resulting ecosystem carbon dynamics. Here we characterize the spatial structure and environmental drivers of soil respiration across a permafrost transition zone. We find that soil respiration is characterized by a non-linear threshold that occurs at active-layer depths greater than 140 cm. We also find that within each season, tree basal area is a dominant driver of soil respiration regardless of spatial scale, but only in spatial domains with significant spatial variability in basal area. Our analyses further show that spatial variation (the coefficient of variation) and mean-variance power-law scaling of soil respiration in our boreal system are consistent with previous work in other ecosystems (e.g., tropical forests) and in population ecology, respectively. Comparing our results to those in other ecosystems suggests that temporally stable features such as tree-stand structure are often primary drivers of spatial variation in soil respiration. If so, this provides an opportunity to better estimate the magnitude and spatial variation in soil respiration through remote sensing. Combining such an approach with broader knowledge of thresholding behavior - here related to active layer depth - would provide empirical constraints on models aimed at predicting ecosystem responses to ongoing permafrost thaw.

  8. Bioirrigation impacts on sediment respiration and microbial metabolic activity

    NASA Astrophysics Data System (ADS)

    Baranov, V. A.; Lewandowski, J.; Romeijn, P.; Krause, S.

    2015-12-01

    Some bioturbators build tubes in the sediment and pump water through their burrows (ventilation). Oxygen is transferred through the burrow walls in the adjacent sediment (bioirrigation). Bioirrigation is playing a pivotal role in the mediation of biogeochemical processes in lake sediments and has the potential to enhance nutrient cycling. The present study investigates the impact of bioirrigation on lake sediment metabolism, respiration rates and in particular, the biogeochemical impacts of bioirrigation intensity as a function of organism density. We therefore apply the bioreactive Resazurin/Resorufin smart tracer system for quantifying the impact of different densities of Chironomidae (Diptera) larvae (0-2112 larvae/m2) on lake sediment respiration in a microcosm experiment. Tracer decay has been found to be proportional to the amount of the aerobic respiration at the sediment-water interface. Tracer transformation was in good agreement with Chironomidae density (correlation, r=0.9). Tracer transformation rates (and sediment respiration) were found to be correlated to Chironomidae density, with highest transformation rates observed in the microcosms with highest density of 2112 larvae/m2. This relationship was not linear though, with sediment respiration rates at the highest larvae densities declining from the linear trend predicted from lower and intermediate larvae density-respiration relationships. We interpret this effect as a density dependent suppression of the Chironomid's metabolic activity. The observations of this study have implications for eutrophied lakes with high densities of bioirrigators. Despite high density of bioirrigirrigating benthos, mineralization of the organic matter in such habitats would likely be lower than in lakes with intermediate densities of the bioturbators.

  9. Foliar and ecosystem respiration in an old-growth tropical rain forest

    Treesearch

    Molly A. Cavaleri; Steven F. Oberbauer; Michael G. Ryan

    2008-01-01

    Foliar respiration is a major component of ecosystem respiration, yet extrapolations are often uncertain in tropical forests because of indirect estimates of leaf area index (LAI).A portable tower was used to directly measure LAI and night-time foliar respiration from 52 vertical transects throughout an old-growth tropical rain forest in Costa Rica. In this study, we (...

  10. Estimating Daytime Ecosystem Respiration to Improve Estimates of Gross Primary Production of a Temperate Forest

    PubMed Central

    Sun, Jinwei; Wu, Jiabing; Guan, Dexin; Yao, Fuqi; Yuan, Fenghui; Wang, Anzhi; Jin, Changjie

    2014-01-01

    Leaf respiration is an important component of carbon exchange in terrestrial ecosystems, and estimates of leaf respiration directly affect the accuracy of ecosystem carbon budgets. Leaf respiration is inhibited by light; therefore, gross primary production (GPP) will be overestimated if the reduction in leaf respiration by light is ignored. However, few studies have quantified GPP overestimation with respect to the degree of light inhibition in forest ecosystems. To determine the effect of light inhibition of leaf respiration on GPP estimation, we assessed the variation in leaf respiration of seedlings of the dominant tree species in an old mixed temperate forest with different photosynthetically active radiation levels using the Laisk method. Canopy respiration was estimated by combining the effect of light inhibition on leaf respiration of these species with within-canopy radiation. Leaf respiration decreased exponentially with an increase in light intensity. Canopy respiration and GPP were overestimated by approximately 20.4% and 4.6%, respectively, when leaf respiration reduction in light was ignored compared with the values obtained when light inhibition of leaf respiration was considered. This study indicates that accurate estimates of daytime ecosystem respiration are needed for the accurate evaluation of carbon budgets in temperate forests. In addition, this study provides a valuable approach to accurately estimate GPP by considering leaf respiration reduction in light in other ecosystems. PMID:25419844

  11. Ammonium excretion and oxygen respiration of tropical copepods and euphausiids exposed to oxygen minimum zone conditions

    NASA Astrophysics Data System (ADS)

    Kiko, R.; Hauss, H.; Buchholz, F.; Melzner, F.

    2015-10-01

    Calanoid copepods and euphausiids are key components of marine zooplankton communities worldwide. Most euphausiids and several copepod species perform diel vertical migrations (DVMs) that contribute to the export of particulate and dissolved matter to midwater depths. In vast areas of the global ocean, and in particular in the eastern tropical Atlantic and Pacific, the daytime distribution depth of many migrating organisms corresponds to the core of the oxygen minimum zone (OMZ). At depth, the animals experience reduced temperature and oxygen partial pressure (pO2) and an increased carbon dioxide partial pressure (pCO2) compared to their near-surface nighttime habitat. Although it is well known that low oxygen levels can inhibit respiratory activity, the respiration response of tropical copepods and euphausiids to relevant pCO2, pO2 and temperature conditions remains poorly parameterized. Further, the regulation of ammonium excretion at OMZ conditions is generally not well understood. It was recently estimated that DVM-mediated ammonium supply considerably fuels bacterial anaerobic ammonium oxidation - a major loss process for fixed nitrogen in the ocean. These estimates were based on the implicit assumption that hypoxia or anoxia in combination with hypercapnia (elevated pCO2) does not result in a downregulation of ammonium excretion. Here we show that exposure to OMZ conditions can result in strong depression of respiration and ammonium excretion in calanoid copepods and euphausiids from the Eastern Tropical North Atlantic and the Eastern Tropical South Pacific. These physiological responses need to be taken into account when estimating DVM-mediated fluxes of carbon and nitrogen into OMZs.

  12. Glycolysis Is Dynamic and Relates Closely to Respiration Rate in Stored Sugarbeet Roots

    PubMed Central

    Megguer, Clarice A.; Fugate, Karen K.; Lafta, Abbas M.; Ferrareze, Jocleita P.; Deckard, Edward L.; Campbell, Larry G.; Lulai, Edward C.; Finger, Fernando L.

    2017-01-01

    Although respiration is the principal cause of the loss of sucrose in postharvest sugarbeet (Beta vulgaris L.), the internal mechanisms that control root respiration rate are unknown. Available evidence, however, indicates that respiration rate is likely to be controlled by the availability of respiratory substrates, and glycolysis has a central role in generating these substrates. To determine glycolytic changes that occur in sugarbeet roots after harvest and to elucidate relationships between glycolysis and respiration, sugarbeet roots were stored for up to 60 days, during which activities of glycolytic enzymes and concentrations of glycolytic substrates, intermediates, cofactors, and products were determined. Respiration rate was also determined, and relationships between respiration rate and glycolytic enzymes and metabolites were evaluated. Glycolysis was highly variable during storage, with 10 of 14 glycolytic activities and 14 of 17 glycolytic metabolites significantly altered during storage. Changes in glycolytic enzyme activities and metabolites occurred throughout the 60 day storage period, but were greatest in the first 4 days after harvest. Positive relationships between changes in glycolytic enzyme activities and root respiration rate were abundant, with 10 of 14 enzyme activities elevated when root respiration was elevated and 9 glycolytic activities static during periods of unchanging respiration rate. Major roles for pyruvate kinase and phosphofructokinase in the regulation of postharvest sugarbeet root glycolysis were indicated based on changes in enzymatic activities and concentrations of their substrates and products. Additionally, a strong positive relationship between respiration rate and pyruvate kinase activity was found indicating that downstream TCA cycle enzymes were unlikely to regulate or restrict root respiration in a major way. Overall, these results establish that glycolysis is not static during sugarbeet root storage and that changes

  13. Influence of menhaden oil on mitochondrial respiration in BHE rats.

    PubMed

    Kim, M J; Berdanier, C D

    1989-11-01

    The effects of corn or menhaden oil and thyroxine treatment on hepatic mitochondrial respiration was studied. BHE rats were fed a 64% sucrose, 6% corn, or menhaden oil diet until they were 60-70 days of age. Succinate-supported mitochondrial respiration was studied at 3 degrees C intervals from 4 to 40 degrees C. Upper and lower activation energies and transition temperatures were determined through the calculation of Arrhenius plot. Menhaden oil plus daily thyroxine injection resulted in higher and lower activation energies than the other treatments. This combined treatment also resulted in lower state 3 and higher state 4 respiration rates and tighter coupling of respiration to ATP synthesis. These effects were thought to be due to the effect this treatment combination had on membrane fluidity.

  14. Particulate residue separators for harvesting devices

    DOEpatents

    Hoskinson, Reed L.; Kenney, Kevin L.; Wright, Christopher T.; Hess, John R.

    2010-06-29

    A particulate residue separator and a method for separating a particulate residue stream may include a plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams which are formed by the harvesting device and which travel, at least in part, along the plenum and in a direction of the second, exhaust end; and a baffle assembly which is located in partially occluding relation relative to the plenum, and which substantially separates the first and second particulate residue air streams.

  15. ESTIMATING ROOT RESPIRATION IN SPRUCE AND BEECH: DECREASES IN SOIL RESPIRATION FOLLOWING GIRDLING

    EPA Science Inventory

    A study was undertaken to follow seasonal fluxes of CO2 from soil and to estimate the contribution of autotrophic (root + mycorrhizal) to total soil respiration (SR) in a mixed stand of European beech (Fagus sylvatica) and Norway spruce (Picea abies) near Freising, Germany. Matu...

  16. Respiration patterns of resting wasps (Vespula sp.)

    PubMed Central

    Käfer, Helmut; Kovac, Helmut; Stabentheiner, Anton

    2013-01-01

    We investigated the respiration patterns of wasps (Vespula sp.) in their viable temperature range (2.9–42.4 °C) by measuring CO2 production and locomotor and endothermic activity. Wasps showed cycles of an interburst–burst type at low ambient temperatures (Ta < 5 °C) or typical discontinuous gas exchange patterns with closed, flutter and open phases. At high Ta of >31 °C, CO2 emission became cyclic. With rising Ta they enhanced CO2-emission primarily by an exponential increase in respiration frequency, from 2.6 mHz at 4.7 °C to 74 mHz at 39.7 °C. In the same range of Ta CO2 release per cycle decreased from 38.9 to 26.4 μl g−1 cycle−1. A comparison of wasps with other insects showed that they are among the insects with a low respiratory frequency at a given resting metabolic rate (RMR), and a relatively flat increase of respiratory frequency with RMR. CO2 emission was always accompanied by abdominal respiration movements in all open phases and in 71.4% of the flutter phases, often accompanied by body movements. Results suggest that resting wasps gain their highly efficient gas exchange to a considerable extent via the length and type of respiration movements. PMID:23399474

  17. Effects of bioirrigation of non-biting midges (Diptera: Chironomidae) on lake sediment respiration

    PubMed Central

    Baranov, Viktor; Lewandowski, Jörg; Romeijn, Paul; Singer, Gabriel; Krause, Stefan

    2016-01-01

    Bioirrigation or the transport of fluids into the sediment matrix due to the activities of organisms such as bloodworms (larvae of Diptera, Chironomidae), has substantial impacts on sediment respiration in lakes. However, previous quantifications of bioirrigation impacts of Chironomidae have been limited by technical challenges such as the difficulty to separate faunal and bacterial respiration. This paper describes a novel method based on the bioreactive tracer resazurin for measuring respiration in-situ in non-sealed systems with constant oxygen supply. Applying this new method in microcosm experiments revealed that bioirrigation enhanced sediment respiration by up to 2.5 times. The new method is yielding lower oxygen consumption than previously reported, as it is only sensitive to aerobic heterotrophous respiration and not to other processes causing oxygen decrease. Hence it decouples the quantification of respiration of animals and inorganic oxygen consumption from microbe respiration in sediment. PMID:27256514

  18. Effects of bioirrigation of non-biting midges (Diptera: Chironomidae) on lake sediment respiration.

    PubMed

    Baranov, Viktor; Lewandowski, Jörg; Romeijn, Paul; Singer, Gabriel; Krause, Stefan

    2016-06-03

    Bioirrigation or the transport of fluids into the sediment matrix due to the activities of organisms such as bloodworms (larvae of Diptera, Chironomidae), has substantial impacts on sediment respiration in lakes. However, previous quantifications of bioirrigation impacts of Chironomidae have been limited by technical challenges such as the difficulty to separate faunal and bacterial respiration. This paper describes a novel method based on the bioreactive tracer resazurin for measuring respiration in-situ in non-sealed systems with constant oxygen supply. Applying this new method in microcosm experiments revealed that bioirrigation enhanced sediment respiration by up to 2.5 times. The new method is yielding lower oxygen consumption than previously reported, as it is only sensitive to aerobic heterotrophous respiration and not to other processes causing oxygen decrease. Hence it decouples the quantification of respiration of animals and inorganic oxygen consumption from microbe respiration in sediment.

  19. Effects of bioirrigation of non-biting midges (Diptera: Chironomidae) on lake sediment respiration

    NASA Astrophysics Data System (ADS)

    Baranov, Viktor; Lewandowski, Jörg; Romeijn, Paul; Singer, Gabriel; Krause, Stefan

    2016-06-01

    Bioirrigation or the transport of fluids into the sediment matrix due to the activities of organisms such as bloodworms (larvae of Diptera, Chironomidae), has substantial impacts on sediment respiration in lakes. However, previous quantifications of bioirrigation impacts of Chironomidae have been limited by technical challenges such as the difficulty to separate faunal and bacterial respiration. This paper describes a novel method based on the bioreactive tracer resazurin for measuring respiration in-situ in non-sealed systems with constant oxygen supply. Applying this new method in microcosm experiments revealed that bioirrigation enhanced sediment respiration by up to 2.5 times. The new method is yielding lower oxygen consumption than previously reported, as it is only sensitive to aerobic heterotrophous respiration and not to other processes causing oxygen decrease. Hence it decouples the quantification of respiration of animals and inorganic oxygen consumption from microbe respiration in sediment.

  20. Automatic patient respiration failure detection system with wireless transmission

    NASA Technical Reports Server (NTRS)

    Dimeff, J.; Pope, J. M.

    1968-01-01

    Automatic respiration failure detection system detects respiration failure in patients with a surgically implanted tracheostomy tube, and actuates an audible and/or visual alarm. The system incorporates a miniature radio transmitter so that the patient is unencumbered by wires yet can be monitored from a remote location.

  1. [Soil respiration and carbon balance in wheat field under conservation tillage].

    PubMed

    Zhang, Sai; Wang, Long-Chang; Huang, Zhao-Cun; Jia, Hui-Juan; Ran, Chun-Yan

    2014-06-01

    In order to study the characteristics of carbon sources and sinks in the winter wheat farmland ecosystem in southwest hilly region of China, the LI6400-09 respiratory chamber was adopted in the experiment conducted in the experimental field in Southwest University in Chongqing. The soil respiration and plant growth dynamics were analyzed during the growth period of wheat in the triple intercropping system of wheat-maize-soybean. Four treatments including T (traditional tillage), R (ridge tillage), TS (traditional tillage + straw mulching), and RS (ridge tillage + straw mulching) were designed. Root biomass regression (RR) and root exclusion (RE) were used to compare the contribution of root respiration to total soil respiration. The results showed that the average soil respiration rate was 1.71 micromol x (m2 x s)(-1) with a variation of 0.62-2.91 micromol x (m2 x s)(-1). Significant differences in soil respiration rate were detected among different treatments. The average soil respiration rate of T, R, TS and RS were 1.29, 1.59, 1.99 and 1.96 micromol x (m2 x s)(-1), respectively. R treatment did not increase the soil respiration rate significantly until the jointing stage. Straw mulching treatment significantly increased soil respiration, with a steadily high rate during the whole growth period. During the 169 days of growth, the total soil respiration was 2 266.82, 2799.52, 3 483.73 and 3 443.89 kg x hm(-2) while the cumulative aboveground biomasses were 51 800.84, 59 563.20, 66 015.37 and 7 1331.63 kg x hm(-2). Compared with the control, the yield of R, TS and RS increased by 14.99%, 27.44% and 37.70%, respectively. The contribution of root respiration to total soil respiration was 47.05% by RBR, while it was 53.97% by RE. In the early growth period, the carbon source was weak. The capacity of carbon sink started to increase at the jointing stage and reached the maximum during the filling stage. The carbon budget of wheat field was 5 924.512, 6743.807, 8350

  2. Fine root morphological traits determine variation in root respiration of Quercus serrata.

    PubMed

    Makita, Naoki; Hirano, Yasuhiro; Dannoura, Masako; Kominami, Yuji; Mizoguchi, Takeo; Ishii, Hiroaki; Kanazawa, Yoichi

    2009-04-01

    Fine root respiration is a significant component of carbon cycling in forest ecosystems. Although fine roots differ functionally from coarse roots, these root types have been distinguished based on arbitrary diameter cut-offs (e.g., 2 or 5 mm). Fine root morphology is directly related to physiological function, but few attempts have been made to understand the relationships between morphology and respiration of fine roots. To examine relationships between respiration rates and morphological traits of fine roots (0.15-1.4 mm in diameter) of mature Quercus serrata Murr., we measured respiration of small fine root segments in the field with a portable closed static chamber system. We found a significant power relationship between mean root diameter and respiration rate. Respiration rates of roots<0.4 mm in mean diameter were high and variable, ranging from 3.8 to 11.3 nmol CO2 g(-1) s(-1), compared with those of larger diameter roots (0.4-1.4 mm), which ranged from 1.8 to 3.0 nmol CO2 g(-1) s(-1). Fine root respiration rate was positively correlated with specific root length (SRL) as well as with root nitrogen (N) concentration. For roots<0.4 mm in diameter, SRL had a wider range (11.3-80.4 m g(-1)) and was more strongly correlated with respiration rate than diameter. Our results indicate that a more detailed classification of fine roots<2.0 mm is needed to represent the heterogeneity of root respiration and to evaluate root biomass and root morphological traits.

  3. Development of a Molecular System for Studying Microbial Arsenate Respiration

    NASA Astrophysics Data System (ADS)

    Saltikov, C. W.; Newman, D. K.

    2002-12-01

    The toxic element arsenic is a major contaminant of many groundwaters and surface waters throughout the world. Arsenic enrichment is primarily of geological origin resulting from weathering processes and geothermal activity. Not surprisingly, microorganisms inhabiting anoxic arsenic-contaminated environments have evolved to exploit arsenate during respiration. Numerous bacteria have been isolated that use arsenate as a terminal electron acceptor for respiratory growth. The diversity of this metabolism appears to be widespread throughout the microbial tree of life, suggesting respiratory arsenate reduction is ancient in origin. Yet little is known about the molecular mechanisms for how these organisms respire arsenate. We have developed a model system in Shewanella trabarsenatis, strain ANA-3, a facultative anaerobe that respires arsenate and tolerates high concentrations of arsenite (10 mM). Through loss-of-function studies, we have identified genes involved in both arsenic resistance and arsenate respiration. The genes that confer resistance to arsenic are homologous to the well-characterized ars operon of E. coli. However, the respiratory arsenate reductase is predicted to encode a novel protein that shares homologous regions (~ 40 % similarity) to molybdopterin anaerobic reductases specific for DMSO, thiosulfate, nitrate, and polysulfide. I will discuss our emerging model for how strain ANA-3 respires arsenate and the relationship between arsenite resistance and arsenate respiration. I will also highlight the relevance of this type of analysis for biogeochemical studies.

  4. Redefinition and global estimation of basal ecosystem respiration rate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yuan, Wenping; Luo, Yiqi; Li, Xianglan

    2011-10-13

    Basal ecosystem respiration rate (BR), the ecosystem respiration rate at a given temperature, is a common and important parameter in empirical models for quantifying ecosystem respiration (ER) globally. Numerous studies have indicated that BR varies in space. However, many empirical ER models still use a global constant BR largely due to the lack of a functional description for BR. In this study, we redefined BR to be ecosystem respiration rate at the mean annual temperature. To test the validity of this concept, we conducted a synthesis analysis using 276 site-years of eddy covariance data, from 79 research sites located atmore » latitudes ranging from ~3°S to ~70°N. Results showed that mean annual ER rate closely matches ER rate at mean annual temperature. Incorporation of site-specific BR into global ER model substantially improved simulated ER compared to an invariant BR at all sites. These results confirm that ER at the mean annual« less

  5. High- and low-pressure pneumotachometers measure respiration rates accurately in adverse environments

    NASA Technical Reports Server (NTRS)

    Fagot, R. J.; Mc Donald, R. T.; Roman, J. A.

    1968-01-01

    Respiration-rate transducers in the form of pneumotachometers measure respiration rates of pilots operating high performance research aircraft. In each low pressure or high pressure oxygen system a sensor is placed in series with the pilots oxygen supply line to detect gas flow accompanying respiration.

  6. Creating the Chemistry in Cellular Respiration Concept Inventory (CCRCI)

    NASA Astrophysics Data System (ADS)

    Forshee, Jay Lance, II

    Students at our institution report cellular respiration to be the most difficult concept they encounter in undergraduate biology, but why students find this difficult is unknown. Students may find cellular respiration difficult because there is a large amount of steps, or because there are persistent, long-lasting misconceptions and misunderstandings surrounding their knowledge of chemistry, which affect their performance on cellular respiration assessments. Most studies of cellular respiration focus on student macro understanding of the process related to breathing, and matter and energy. To date, no studies identify which chemistry concepts are most relevant to students' development of an understanding of the process of cellular respiration or have developed an assessment to measure student understanding of them. Following the Delphi method, the researchers conducted expert interviews with faculty members from four-year, masters-, and PhD-granting institutions who teach undergraduate general biology, and are experts in their respective fields of biology. From these interviews, researchers identified twelve chemistry concepts important to understanding cellular respiration and using surveys, these twelve concepts were refined into five (electron transfer, energy transfer, thermodynamics (law/conservation), chemical reactions, and gradients). The researchers then interviewed undergraduate introductory biology students at a large Midwestern university to identify their knowledge and misconceptions of the chemistry concepts that the faculty had identified previously as important. The CCRCI was developed using the five important chemistry concepts underlying cellular respiration. The final version of the CCRCI was administered to n=160 introductory biology students during the spring 2017 semester. Reliability of the CCRCI was evaluated using Cronbach's alpha (=.7) and split-half reliability (=.769), and validity of the instrument was assessed through content validity

  7. Basics of Sterile Compounding: Particulate Matter.

    PubMed

    Akers, Michael J

    2017-01-01

    This article focuses on the requirements for particulate matter in sterile products. Topics include particles and quality, particulate matter standards (large- and small-volume injectables), development of the small-volume injectable test, electronic (light obscuration) and microscope testing, and special requirements for particulate matter in biopharmaceutical preparations. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

  8. 20 CFR 718.303 - Death from a respirable disease.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Death from a respirable disease. 718.303... OR DEATH DUE TO PNEUMOCONIOSIS Presumptions Applicable to Eligibility Determinations § 718.303 Death... death was due to pneumoconiosis. (2) Under this presumption, death shall be found due to a respirable...

  9. Evaluation of the Survivability of Microorganisms Deposited on Filtering Respiratory Protective Devices under Varying Conditions of Humidity

    PubMed Central

    Majchrzycka, Katarzyna; Okrasa, Małgorzata; Skóra, Justyna; Gutarowska, Beata

    2016-01-01

    Bioaerosols are common biological factors in work environments, which require routine use of filtering respiratory protective devices (FRPDs). Currently, no studies link humidity changes in the filter materials of such devices, during use, with microorganism survivability. Our aim was to determine the microclimate inside FRPDs, by simulating breathing, and to evaluate microorganism survivability under varying humidity conditions. Breathing was simulated using commercial filtering facepiece respirators in a model system. Polypropylene melt-blown nonwoven fabrics with moisture contents of 40%, 80%, and 200%, were used for assessment of microorganisms survivability. A modified AATCC 100-2004 method was used to measure the survivability of ATCC and NCAIM microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albicans and Aspergillus niger. During simulation relative humidity under the facepiece increased after 7 min of usage to 84%–92% and temperature increased to 29–30 °C. S. aureus survived the best on filter materials with 40%–200% moisture content. A decrease in survivability was observed for E. coli and C. albicans when mass humidity decreased. We found that B. subtilis and A. niger proliferated for 48–72 h of incubation and then died regardless of the moisture content. In conclusion, our tests showed that the survivability of microorganisms on filter materials depends on the amount of accumulated moisture and microorganism type. PMID:26742049

  10. Methods of separating particulate residue streams

    DOEpatents

    Hoskinson, Reed L [Rigby, ID; Kenney, Kevin L [Idaho Falls, ID; Wright, Christopher T [Idaho Falls, ID; Hess, J Richard [Idaho Falls, ID

    2011-04-05

    A particulate residue separator and a method for separating a particulate residue stream may include an air plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams that are formed by the harvesting device and that travel, at least in part, along the air plenum and in a direction of the second, exhaust end; and a baffle assembly that is located in partially occluding relation relative to the air plenum and that substantially separates the first and second particulate residue air streams.

  11. Combined exposure of diesel exhaust particles and respirable Soufrière Hills volcanic ash causes a (pro-)inflammatory response in an in vitro multicellular epithelial tissue barrier model.

    PubMed

    Tomašek, Ines; Horwell, Claire J; Damby, David E; Barošová, Hana; Geers, Christoph; Petri-Fink, Alke; Rothen-Rutishauser, Barbara; Clift, Martin J D

    2016-12-12

    There are justifiable health concerns regarding the potential adverse effects associated with human exposure to volcanic ash (VA) particles, especially when considering communities living in urban areas already exposed to heightened air pollution. The aim of this study was, therefore, to gain an imperative, first understanding of the biological impacts of respirable VA when exposed concomitantly with diesel particles. A sophisticated in vitro 3D triple cell co-culture model of the human alveolar epithelial tissue barrier was exposed to either a single or repeated dose of dry respirable VA (deposited dose of 0.26 ± 0.09 or 0.89 ± 0.29 μg/cm 2 , respectively) from Soufrière Hills volcano, Montserrat for a period of 24 h at the air-liquid interface (ALI). Subsequently, co-cultures were exposed to co-exposures of single or repeated VA and diesel exhaust particles (DEP; NIST SRM 2975; 0.02 mg/mL), a model urban pollutant, at the pseudo-ALI. The biological impact of each individual particle type was also analysed under these precise scenarios. The cytotoxic (LDH release), oxidative stress (depletion of intracellular GSH) and (pro-)inflammatory (TNF-α, IL-8 and IL-1β) responses were assessed after the particulate exposures. The impact of VA exposure upon cell morphology, as well as its interaction with the multicellular model, was visualised via confocal laser scanning microscopy (LSM) and scanning electron microscopy (SEM), respectively. The combination of respirable VA and DEP, in all scenarios, incited an heightened release of TNF-α and IL-8 as well as significant increases in IL-1β, when applied at sub-lethal doses to the co-culture compared to VA exposure alone. Notably, the augmented (pro-)inflammatory responses observed were not mediated by oxidative stress. LSM supported the quantitative assessment of cytotoxicity, with no changes in cell morphology within the barrier model evident. A direct interaction of the VA with all three cell types of

  12. Combined exposure of diesel exhaust particles and respirable Soufrière Hills volcanic ash causes a (pro-)inflammatory response in an in vitro multicellular epithelial tissue barrier model

    USGS Publications Warehouse

    Tomašek, Ines; Horwell, Claire J.; Damby, David; Barošová, Hana; Geers, Christoph; Petri-Fink, Alke; Rothen-Rutishauser, Barbara; Clift, Martin J. D.

    2016-01-01

    BackgroundThere are justifiable health concerns regarding the potential adverse effects associated with human exposure to volcanic ash (VA) particles, especially when considering communities living in urban areas already exposed to heightened air pollution. The aim of this study was, therefore, to gain an imperative, first understanding of the biological impacts of respirable VA when exposed concomitantly with diesel particles.MethodsA sophisticated in vitro 3D triple cell co-culture model of the human alveolar epithelial tissue barrier was exposed to either a single or repeated dose of dry respirable VA (deposited dose of 0.26 ± 0.09 or 0.89 ± 0.29 μg/cm2, respectively) from Soufrière Hills volcano, Montserrat for a period of 24 h at the air-liquid interface (ALI). Subsequently, co-cultures were exposed to co-exposures of single or repeated VA and diesel exhaust particles (DEP; NIST SRM 2975; 0.02 mg/mL), a model urban pollutant, at the pseudo-ALI. The biological impact of each individual particle type was also analysed under these precise scenarios. The cytotoxic (LDH release), oxidative stress (depletion of intracellular GSH) and (pro-)inflammatory (TNF-α, IL-8 and IL-1β) responses were assessed after the particulate exposures. The impact of VA exposure upon cell morphology, as well as its interaction with the multicellular model, was visualised via confocal laser scanning microscopy (LSM) and scanning electron microscopy (SEM), respectively.ResultsThe combination of respirable VA and DEP, in all scenarios, incited an heightened release of TNF-α and IL-8 as well as significant increases in IL-1β, when applied at sub-lethal doses to the co-culture compared to VA exposure alone. Notably, the augmented (pro-)inflammatory responses observed were not mediated by oxidative stress. LSM supported the quantitative assessment of cytotoxicity, with no changes in cell morphology within the barrier model evident. A direct interaction of the VA with all

  13. Forest thinning and soil respiration in a ponderosa pine plantation in the Sierra Nevada.

    PubMed

    Tang, Jianwu; Qi, Ye; Xu, Ming; Misson, Laurent; Goldstein, Allen H

    2005-01-01

    Soil respiration is controlled by soil temperature, soil water, fine roots, microbial activity, and soil physical and chemical properties. Forest thinning changes soil temperature, soil water content, and root density and activity, and thus changes soil respiration. We measured soil respiration monthly and soil temperature and volumetric soil water continuously in a young ponderosa pine (Pinus ponderosa Dougl. ex P. Laws. & C. Laws.) plantation in the Sierra Nevada Mountains in California from June 1998 to May 2000 (before a thinning that removed 30% of the biomass), and from May to December 2001 (after thinning). Thinning increased the spatial homogeneity of soil temperature and respiration. We conducted a multivariate analysis with two independent variables of soil temperature and water and a categorical variable representing the thinning event to simulate soil respiration and assess the effect of thinning. Thinning did not change the sensitivity of soil respiration to temperature or to water, but decreased total soil respiration by 13% at a given temperature and water content. This decrease in soil respiration was likely associated with the decrease in root density after thinning. With a model driven by continuous soil temperature and water time series, we estimated that total soil respiration was 948, 949 and 831 g C m(-2) year(-1) in the years 1999, 2000 and 2001, respectively. Although thinning reduced soil respiration at a given temperature and water content, because of natural climate variability and the thinning effect on soil temperature and water, actual cumulative soil respiration showed no clear trend following thinning. We conclude that the effect of forest thinning on soil respiration is the combined result of a decrease in root respiration, an increase in soil organic matter, and changes in soil temperature and water due to both thinning and interannual climate variability.

  14. [Comparison of soil respiration in natural Castanopsis carlesii forest and plantation forest].

    PubMed

    Wu, Jun-Jun; Yang, Zhi-Jie; Weng, Fa-Jin; Liu, Xiao-Fei; Chen, Chao-Qi; Lin, Wei-Sheng; Wang, Xiao-Hong; Chen, Tan

    2014-06-01

    By using the Li-8100 open soil carbon flux system, the dynamic change of soil respiration rate in natural Castanopsis carlesii and plantation of Castanopsis carlesii forests in Geshikao Nature Reserve in Fujian Province of China were measured from January 2011 to December 2011, with the relationship between the dynamic changes and the relation affecting factors analyzed. The monthly variation of soil respiration in the two types of forests were both single-peaked,with the peaks appeared in early June [7.03 micromol x (m2 x s) (-1)] andlate July [5.12 micromol x (m2 x s)(-1)], respectively. The average annual soil respiration rates of the two forests were 3.74 micromol x (m2 x s)(-1) and 3.05 micromol x (m2 x s)(-1), respectively, showing significant difference. Soil temperature was the main factor affecting soil respiration, explaining 80.1% and 81.0% of the monthly variation of soil respiration. There was a significant positive correlation between the soil respiration rate and soil moisture content in natural Castanopsis carlesii forest, but lower correlation in plantation of Castanopsis carlesii forest. The soil respiration had extremely significant correlation with the litterfall mass of the current month and the month before. The Q10 values of soil respiration in natural Castanopsis carlesii and plantation of Castanopsis carlesii forests were 1.86 and 2.01, and the annual CO2 fluxes were 14.34 t x (hm2 x a)(-1) and 11.18 t x (hm2 x a)(-1), respectively. The soil respiration declined by 22.03% after natural forest was changed to plantation forest.

  15. Observed Home Dampness and Mold Are Associated with Sustained Spikes in Personal Exposure to Particulate Matter Less than 10 μm in Diameter in Exacerbation-Prone Children with Asthma.

    PubMed

    Dutmer, Cullen M; Schiltz, Allison M; Freeman, Kristy L; Christie, Matthew J; Cerna, Juana A; Cho, Seung-Hyun; Chartier, Ryan T; Thornburg, Jonathan W; Hamlington, Katharine L; Crooks, James L; Fingerlin, Tasha E; Schwartz, David A; Liu, Andrew H

    2018-04-01

    particulate matter less than 10 μm in diameter during sustained spike exposures that occurred when participants were home (normalized by total duration of sustained spike exposures) was associated with cumulative drips/leaks/wet areas (r 2  = 0.27; P = 0.004), mold/mildew (r 2  = 0.15; P = 0.04), and water damage/moisture/mold (r 2  = 0.14; P = 0.04). Other measures of exposure to particulate matter less than 10 μm in diameter from personal or stationary monitors were not associated with home dampness or mold indicators. Although mold exposure was not directly quantified in the respirable aerosol in this study, observations of home dampness and mold were associated with sustained spikes in respirable particulate matter less than 10 μm in diameter that was measured by wearable real-time monitors. In our cohort of at-risk children, this finding could imply that mold may exert respiratory health effects via sustained spikes in exposure and help to guide future studies and interventions to reduce these spikes and improve asthma outcomes.

  16. Primary productivity (PP) in the North Pacific Subtropical Gyre: Understanding drivers of variability via 14C-tracer incubations and PP diagnosed via the diurnal cycle of particulate carbon.

    NASA Astrophysics Data System (ADS)

    White, A. E.; Letelier, R. M.

    2016-02-01

    The rate of primary production (PP) in the ocean is a fundamental step in the ocean's food web and biological carbon pump. For more than 50 years oceanographers have relied primarily on estimates of PP based on in vitro measurements of 14CO2 uptake rates. Yet, it is difficult to reconcile PP rates measured in vitro with in situ rates. Here we present diurnal cycles of optically-derived particulate organic carbon (POC) and particle size distributions measured over a series of cruises in the North Pacific relative to traditional 14C-based PP measurements. We have calculated net PP from the daytime increase in optically-derived particulate organic carbon (POC) and the sum of respiration, grazing and sinking from the nighttime POM decrease. Comparison of optically derived NPP to parallel 12-hr 14C incubations are highly significant. The variability in productivity measurements over daily to seasonal to annual time-scales are discussed relative to predominant chemical, physical and climactic forcing.

  17. Phenophases alter the soil respiration-temperature relationship in an oak-dominated forest

    Treesearch

    Jared L. DeForest; Askoo Noormets; Steve G. McNulty; Ge Sun; Gwen Teeney; Jiquan Chen

    2006-01-01

    Soil respiration (SR) represents a major component of forest ecosystem respiration and is influenced seasonally by environmental factors such as temperature, soil moisture, root respiration, and litter fall. Changes in these environmental factors correspond with shifts in plant phenology. In this study, we examined the relationship between canopy phenophases @re-growth...

  18. Utah Regional Differences in Respirator Use and Fit Testing among Pesticide Applicators.

    PubMed

    Pate, Michael L; Beard, F Richard; Hall, Kelsey

    2017-01-26

    The purpose of this study was to determine regional differences within Utah in response to piloting a mobile respirator training and fit assessment program for pesticide applicators. The objectives were to describe worker perceptions of respirator use and training experiences. Pilot trainings were offered in two southern counties and two northern counties of Utah. A total of 141 individuals completed the post-training questionnaire regarding use and fit testing experience with respirators as well as perceptions of the benefits to protecting respiratory health. The majority of respondents were male (95.7%, f = 112). The proportion of participants in the southern counties who had respirator training experience (61.0%, f = 25) was not significantly higher (2 = 3.763, df = 1, p = 0.05) than the proportion of participants in the northern counties (43.0%, f = 43). Three-fourths (73.5%, f = 72) of participants in the northern counties agreed that they expect to wear a respirator in dusty conditions, while two-thirds (61.0%, f = 25) of participants in the southern counties agreed that they expect to wear a respirator in dusty conditions. The results indicated that more training should be done to improve perceptions and beliefs about using respirators. A high priority for this population will be identification of comfortable respirator options as well as communicating the importance of proper fit testing. Copyright© by the American Society of Agricultural Engineers.

  19. Automatic respiration tracking for radiotherapy using optical 3D camera

    NASA Astrophysics Data System (ADS)

    Li, Tuotuo; Geng, Jason; Li, Shidong

    2013-03-01

    Rapid optical three-dimensional (O3D) imaging systems provide accurate digitized 3D surface data in real-time, with no patient contact nor radiation. The accurate 3D surface images offer crucial information in image-guided radiation therapy (IGRT) treatments for accurate patient repositioning and respiration management. However, applications of O3D imaging techniques to image-guided radiotherapy have been clinically challenged by body deformation, pathological and anatomical variations among individual patients, extremely high dimensionality of the 3D surface data, and irregular respiration motion. In existing clinical radiation therapy (RT) procedures target displacements are caused by (1) inter-fractional anatomy changes due to weight, swell, food/water intake; (2) intra-fractional variations from anatomy changes within any treatment session due to voluntary/involuntary physiologic processes (e.g. respiration, muscle relaxation); (3) patient setup misalignment in daily reposition due to user errors; and (4) changes of marker or positioning device, etc. Presently, viable solution is lacking for in-vivo tracking of target motion and anatomy changes during the beam-on time without exposing patient with additional ionized radiation or high magnet field. Current O3D-guided radiotherapy systems relay on selected points or areas in the 3D surface to track surface motion. The configuration of the marks or areas may change with time that makes it inconsistent in quantifying and interpreting the respiration patterns. To meet the challenge of performing real-time respiration tracking using O3D imaging technology in IGRT, we propose a new approach to automatic respiration motion analysis based on linear dimensionality reduction technique based on PCA (principle component analysis). Optical 3D image sequence is decomposed with principle component analysis into a limited number of independent (orthogonal) motion patterns (a low dimension eigen-space span by eigen-vectors). New

  20. 20 CFR 718.303 - Death from a respirable disease.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false Death from a respirable disease. 718.303... DISABILITY OR DEATH DUE TO PNEUMOCONIOSIS Presumptions Applicable to Eligibility Determinations § 718.303 Death from a respirable disease. (a)(1) If a deceased miner was employed for ten or more years in one or...

  1. 20 CFR 718.303 - Death from a respirable disease.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false Death from a respirable disease. 718.303... DISABILITY OR DEATH DUE TO PNEUMOCONIOSIS Presumptions Applicable to Eligibility Determinations § 718.303 Death from a respirable disease. (a)(1) If a deceased miner was employed for ten or more years in one or...

  2. The Intrinsic Temperature Sensitivity of Ecosystem Respiration as Explained by Thermodynamics

    NASA Astrophysics Data System (ADS)

    Woods, K. D.; Arcus, V. L.; Schipper, L. A.; Schwalm, C.

    2016-12-01

    Biological processes exhibit thermal optima; a range within which processes such as photosynthesis and respiration reach a maximum rate. The response of these processes to temperature is well observed in the field and lab experiments, but is poorly captured or explained by widely used Arrhenius equations and Q10 constants. Both Arrhenius and Q10-based explanations of respiration misleadingly project an exponential increase in rate with temperature and rely on concepts such as enzyme denaturation to explain decreases at higher temperatures. This explanation is problematic in that it ignores observed declines which are far below experimental observations of enzyme denaturation. Here, we present a novel theory which explains the intrinsic temperature dependence of plant, soil, and ecosystem respiration based on the thermodynamics of enzyme-catalysed reactions. MacroMolecular Rate Theory (MMRT) allows for the calculation of thermal optima for respiration and photosynthesis (an important input substrate for respiration), as well as for the calculation of the curvature of response which defines temperatures where changes in rates are maximal. To test this theory, we used the recently released FLUXNET2015 dataset which is comprised of 165 sites and 23 years of data. We accounted for the effect of water through partial correlation analysis and extracted the temperature signal of respiration and photosynthesis to fit MacroMolecular Rate Theory. Across ecosystems and biomes, photosynthesis and respiration rates maximized at 7-18oC and 15-27oC respectively. At 16-25oC, and 26-36oC rates photosynthesis and respiration declined. These points, and this method for explaining changes in these processes are important for understanding and predicting net ecosystem carbon gain or loss. They demonstrate temperatures where the sign and magnitude of carbon exchange undergoes important shifts, holding important implications for future carbon cycling.

  3. Replacement of filters for respirable quartz measurement in coal mine dust by infrared spectroscopy.

    PubMed

    Farcas, Daniel; Lee, Taekhee; Chisholm, William P; Soo, Jhy-Charm; Harper, Martin

    2016-01-01

    The objective of this article is to compare and characterize nylon, polypropylene (PP), and polyvinyl chloride (PVC) membrane filters that might be used to replace the vinyl/acrylic co-polymer (DM-450) filter currently used in the Mine Safety and Health Administration (MSHA) P-7 method (Quartz Analytical Method) and the National Institute for Occupational Safety and Health (NIOSH) Manual of Analytical Methods 7603 method (QUARTZ in coal mine dust, by IR re-deposition). This effort is necessary because the DM-450 filters are no longer commercially available. There is an impending shortage of DM-450 filters. For example, the MSHA Pittsburgh laboratory alone analyzes annually approximately 15,000 samples according to the MSHA P-7 method that requires DM-450 filters. Membrane filters suitable for on-filter analysis should have high infrared (IR) transmittance in the spectral region 600-1000 cm(-1). Nylon (47 mm, 0.45 µm pore size), PP (47 mm, 0.45 µm pore size), and PVC (47 mm, 5 µm pore size) filters meet this specification. Limits of detection and limits of quantification were determined from Fourier transform infrared spectroscopy (FTIR) measurements of blank filters. The average measured quartz mass and coefficient of variation were determined from test filters spiked with respirable α-quartz following MSHA P-7 and NIOSH 7603 methods. Quartz was also quantified in samples of respirable coal dust on each test filter type using the MSHA and NIOSH analysis methods. The results indicate that PP and PVC filters may replace the DM-450 filters for quartz measurement in coal dust by FTIR. PVC filters of 5 µm pore size seemed to be suitable replacement although their ability to retain small particulates should be checked by further experiment.

  4. A KINETIC ANALYSIS OF THE ENDOGENOUS RESPIRATION OF BAKERS' YEAST

    PubMed Central

    Stier, T. J. B.; Stannard, J. N.

    1936-01-01

    The process of endogenous respiration of two strains of bakers' yeast, Saccharomyces cerevisiae, was examined kinetically. The rate of respiration with respect to time in a non-nutrient medium was found to exhibit two phases: (a) a period of constant rate of O2 consumption and CO2 production (R.Q. = 1) characteristic of cells with ample concentrations of stored material; (b) a first order decline in rate of respiration with respect to time, where the rate was proportional to the concentration of some substrate, S. (R.Q. = 1 throughout second phase.) The nature of this substrate was reexamined and the evidence summarized confirms the notion that it is a carbohydrate, probably glycogen. These phases of endogenous respiration were shown to depend upon the age of the culture and the amount of substrate available. PMID:19872942

  5. Significance of heme-based respiration in meat spoilage caused by Leuconostoc gasicomitatum.

    PubMed

    Jääskeläinen, Elina; Johansson, Per; Kostiainen, Olli; Nieminen, Timo; Schmidt, Georg; Somervuo, Panu; Mohsina, Marzia; Vanninen, Paula; Auvinen, Petri; Björkroth, Johanna

    2013-02-01

    Leuconostoc gasicomitatum is a psychrotrophic lactic acid bacterium (LAB) which causes spoilage in cold-stored modified-atmosphere-packaged (MAP) meat products. In addition to the fermentative metabolism, L. gasicomitatum is able to respire when exogenous heme and oxygen are available. In this study, we investigated the respiration effects on growth rate, biomass, gene expression, and volatile organic compound (VOC) production in laboratory media and pork loin. The meat samples were evaluated by a sensory panel every second or third day for 29 days. We observed that functional respiration increased the growth (rate and yield) of L. gasicomitatum in laboratory media with added heme and in situ meat with endogenous heme. Respiration increased enormously (up to 2,600-fold) the accumulation of acetoin and diacetyl, which are buttery off-odor compounds in meat. Our transcriptome analyses showed that the gene expression patterns were quite similar, irrespective of whether respiration was turned off by excluding heme from the medium or mutating the cydB gene, which is essential in the respiratory chain. The respiration-based growth of L. gasicomitatum in meat was obtained in terms of population development and subsequent development of sensory characteristics. Respiration is thus a key factor explaining why L. gasicomitatum is so well adapted in high-oxygen packed meat.

  6. Soil respiration in different agricultural and natural ecosystems in an arid region.

    PubMed

    Lai, Liming; Zhao, Xuechun; Jiang, Lianhe; Wang, Yongji; Luo, Liangguo; Zheng, Yuanrun; Chen, Xi; Rimmington, Glyn M

    2012-01-01

    The variation of different ecosystems on the terrestrial carbon balance is predicted to be large. We investigated a typical arid region with widespread saline/alkaline soils, and evaluated soil respiration of different agricultural and natural ecosystems. Soil respiration for five ecosystems together with soil temperature, soil moisture, soil pH, soil electric conductivity and soil organic carbon content were investigated in the field. Comparing with the natural ecosystems, the mean seasonal soil respiration rates of the agricultural ecosystems were 96%-386% higher and agricultural ecosystems exhibited lower CO(2) absorption by the saline/alkaline soil. Soil temperature and moisture together explained 48%, 86%, 84%, 54% and 54% of the seasonal variations of soil respiration in the five ecosystems, respectively. There was a significant negative relationship between soil respiration and soil electrical conductivity, but a weak correlation between soil respiration and soil pH or soil organic carbon content. Our results showed that soil CO(2) emissions were significantly different among different agricultural and natural ecosystems, although we caution that this was an observational, not manipulative, study. Temperature at the soil surface and electric conductivity were the main driving factors of soil respiration across the five ecosystems. Care should be taken when converting native vegetation into cropland from the point of view of greenhouse gas emissions.

  7. BOREAS TE-2 Continuous Wood Respiration Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Papagno, Andrea (Editor); Ryan, Michael G.; Lavigne, Michael

    2000-01-01

    The BOREAS TE-2 team collected several data sets in support of its efforts to characterize and interpret information on the respiration of the foliage, roots, and wood of boreal vegetation. This data set contains measurements of wood respiration measured continuously (about once per hour) in the NSA during the growing season of 1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  8. Effect of Simvastatin, Coenzyme Q10, Resveratrol, Acetylcysteine and Acetylcarnitine on Mitochondrial Respiration.

    PubMed

    Fišar, Z; Hroudová, J; Singh, N; Kopřivová, A; Macečková, D

    2016-01-01

    Some therapeutic and/or adverse effects of drugs may be related to their effects on mitochondrial function. The effects of simvastatin, resveratrol, coenzyme Q10, acetylcysteine, and acetylcarnitine on Complex I-, Complex II-, or Complex IV-linked respiratory rate were determined in isolated brain mitochondria. The protective effects of these biologically active compounds on the calcium-induced decrease of the respiratory rate were also studied. We observed a significant inhibitory effect of simvastatin on mitochondrial respiration (IC50 = 24.0 μM for Complex I-linked respiration, IC50 = 31.3 μM for Complex II-linked respiration, and IC50 = 42.9 μM for Complex IV-linked respiration); the inhibitory effect of resveratrol was found at very high concentrations (IC50 = 162 μM for Complex I-linked respiration, IC50 = 564 μM for Complex II-linked respiration, and IC50 = 1454 μM for Complex IV-linked respiration). Concentrations required for effective simvastatin- or resveratrol-induced inhibition of mitochondrial respiration were found much higher than concentrations achieved under standard dosing of these drugs. Acetylcysteine and acetylcarnitine did not affect the oxygen consumption rate of mitochondria. Coenzyme Q10 induced an increase of Complex I-linked respiration. The increase of free calcium ions induced partial inhibition of the Complex I+II-linked mitochondrial respiration, and all tested drugs counteracted this inhibition. None of the tested drugs showed mitochondrial toxicity (characterized by respiratory rate inhibition) at drug concentrations achieved at therapeutic drug intake. Resveratrol, simvastatin, and acetylcarnitine had the greatest neuroprotective potential (characterized by protective effects against calcium-induced reduction of the respiratory rate).

  9. Modeling pulsed soil respiration in an African savanna ecosystem

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fan, Zhaosheng; Neff, Jason C.; Hanan, Niall P.

    2015-01-01

    Savannas cover 60% of the African continent and play an important role in the global carbon (C) emissions from fire and land use. To better characterize the biophysical controls over soil respiration in these settings, half-hourly observations of volumetric soil-water content, temperature, and the concentration of carbon dioxide (CO2) at different soil depths were continually measured from 2005 to 2007 under trees ("sub-canopy") and between trees ("inter-canopy") in a savanna vegetation near Skukuza, Kruger National Park, South Africa. The measured soil climate and CO2 concentration data were assimilated into a process-based model that estimates the CO2 production and flux withmore » coupled dynamics of dissolved organic C (DOC) and microbial biomass C. Our results show that temporal and spatial variations in CO2 flux were strongly influenced by precipitation and vegetation cover, with two times greater CO2 flux in the subcanopy plots (similar to 2421 g CO2 m(-2) yr(-1)) than in the inter-canopy plots (similar to 1290 g CO2 m(-2) yr(-1)). Precipitation influenced soil respiration by changing soil temperature and moisture; however, our modeling analysis suggests that the pulsed response of soil respiration to precipitation events (known as "Birch effect") is a key control on soil fluxes at this site. At this site, "Birch effect" contributed to approximately 50% and 65% of heterotrophic respiration or 20% and 39% of soil respiration in the sub-canopy and inter-canopy plots, respectively. These results suggest that pulsed response of respiration to precipitation events is an important component of the C cycle of savannas and should be considered in both measurement and modeling studies of carbon exchange in similar ecosystems. (C) 2014 Elsevier B.V. All rights reserved.« less

  10. Evaluation of respiration-correlated digital tomosynthesis in lung.

    PubMed

    Santoro, Joseph; Kriminski, Sergey; Lovelock, D Michael; Rosenzweig, Kenneth; Mostafavi, Hassan; Amols, Howard I; Mageras, Gig S

    2010-03-01

    Digital tomosynthesis (DTS) with a linear accelerator-mounted imaging system provides a means of reconstructing tomographic images from radiographic projections over a limited gantry arc, thus requiring only a few seconds to acquire. Its application in the thorax, however, often results in blurred images from respiration-induced motion. This work evaluates the feasibility of respiration-correlated (RC) DTS for soft-tissue visualization and patient positioning. Image data acquired with a gantry-mounted kilovoltage imaging system while recording respiration were retrospectively analyzed from patients receiving radiotherapy for non-small-cell lung carcinoma. Projection images spanning an approximately 30 degrees gantry arc were sorted into four respiration phase bins prior to DTS reconstruction, which uses a backprojection, followed by a procedure to suppress structures above and below the reconstruction plane of interest. The DTS images were reconstructed in planes at different depths through the patient and normal to a user-selected angle close to the center of the arc. The localization accuracy of RC-DTS was assessed via a comparison with CBCT. Evaluation of RC-DTS in eight tumors shows visible reduction in image blur caused by the respiratory motion. It also allows the visualization of tumor motion extent. The best image quality is achieved at the end-exhalation phase of the respiratory motion. Comparison of RC-DTS with respiration-correlated cone-beam CT in determining tumor position, motion extent and displacement between treatment sessions shows agreement in most cases within 2-3 mm, comparable in magnitude to the intraobserver repeatability of the measurement. These results suggest the method's applicability for soft-tissue image guidance in lung, but must be confirmed with further studies in larger numbers of patients.

  11. Soil respiration response to experimental disturbances over 3 years

    Treesearch

    Amy Concilio; Siyan Ma; Soung-Ryoul Ryu; Malcolm North; Jiquan Chen

    2006-01-01

    Soil respiration is a major pathway for carbon cycling in terrestrial ecosystems yet little is known about its response to natural and anthropogenic disturbances. This study examined soil respiration response to prescribed burning and thinning treatments in an old-growth, mixed-conifer forest on the western slope of the Sierra Nevada Mountains. Experimental treatments...

  12. Effect of time, temperature, and slicing on respiration rate of mushrooms.

    PubMed

    Iqbal, T; Rodrigues, F A S; Mahajan, P V; Kerry, J P

    2009-08-01

    Respiration rate measurement considering the effects of cutting, temperature, and storage time are important for the shelf life study and modified atmosphere-packaging design of fresh-cut produce. This study investigates in the respiration rate of fresh whole and sliced mushrooms at 0, 4, 8, 12, 16, and 20 degrees C under ambient atmosphere and different storage times. The O(2) consumption rate increased with temperature and ranged from 22.13 to 102.41 mL/(kg.h) and 28.87 to 143.22 mL/(kg.h) for whole and sliced mushrooms, respectively, in the temperature range tested. Similar trend was observed for CO(2) production rate. Slicing of mushrooms increased the respiration rate by 30% at 0 degrees C and 40% at 20 degrees C indicating that the mushrooms are not as sensitive to the stress caused by cutting as other fresh produce. Storage time affected both respiration rate of whole and sliced mushrooms and this effect was prominent at higher temperatures. The respiration rates increased initially for some time, then decreased and reached steady state value at 12, 16, and 20 degrees C. A 2nd-order polynomial equation was used to fit the respiration rate data as a function of time at each temperature tested.

  13. Leaf respiration ( GlobResp) - global trait database supports Earth System Models

    DOE PAGES

    Wullschleger, Stan D.; Warren, Jeffrey; Thornton, Peter E.

    2015-03-20

    Here we detail how Atkin and his colleagues compiled a global database (GlobResp) that details rates of leaf dark respiration and associated traits from sites that span Arctic tundra to tropical forests. This compilation builds upon earlier research (Reich et al., 1998; Wright et al., 2006) and was supplemented by recent field campaigns and unpublished data.In keeping with other trait databases, GlobResp provides insights on how physiological traits, especially rates of dark respiration, vary as a function of environment and how that variation can be used to inform terrestrial biosphere models and land surface components of Earth System Models. Althoughmore » an important component of plant and ecosystem carbon (C) budgets (Wythers et al., 2013), respiration has only limited representation in models. Seen through the eyes of a plant scientist, Atkin et al. (2015) give readers a unique perspective on the climatic controls on respiration, thermal acclimation and evolutionary adaptation of dark respiration, and insights into the covariation of respiration with other leaf traits. We find there is ample evidence that once large databases are compiled, like GlobResp, they can reveal new knowledge of plant function and provide a valuable resource for hypothesis testing and model development.« less

  14. 40 CFR 60.422 - Standards for particulate matter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards for particulate matter. 60... Manufacture § 60.422 Standards for particulate matter. On or after the date on which the performance test... sulfate dryer, particulate matter at an emission rate exceeding 0.15 kilogram of particulate per megagram...

  15. 40 CFR 60.422 - Standards for particulate matter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards for particulate matter. 60... Manufacture § 60.422 Standards for particulate matter. On or after the date on which the performance test... sulfate dryer, particulate matter at an emission rate exceeding 0.15 kilogram of particulate per megagram...

  16. 40 CFR 60.422 - Standards for particulate matter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards for particulate matter. 60... Manufacture § 60.422 Standards for particulate matter. On or after the date on which the performance test... sulfate dryer, particulate matter at an emission rate exceeding 0.15 kilogram of particulate per megagram...

  17. 40 CFR 60.422 - Standards for particulate matter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards for particulate matter. 60... Manufacture § 60.422 Standards for particulate matter. On or after the date on which the performance test... sulfate dryer, particulate matter at an emission rate exceeding 0.15 kilogram of particulate per megagram...

  18. Cytochrome and Alternative Pathway Respiration in Green Algae 1

    PubMed Central

    Weger, Harold G.; Guy, Robert D.; Turpin, David H.

    1990-01-01

    Inhibitor titration curves and discrimination against 18O2 by mitochondrial respiration in three strains of green algae (Selenastrum minutum [Naeg.] Collins, and two strains of Chlamydomonas reinhardtii Dangeard) with differing respiratory capabilities were determined. Discrimination for cytochrome pathway respiration ranged from 19.89 to 20.43%. Discrimination for alternative pathway respiration by wild-type C. reinhardtii (measured in the presence of KCN) was 25.46%, while discrimination values for a cytochrome oxidase deficient mutant of C. reinhardtii ranged from 24.24 to 24.96%. In the absence of KCN, the alternative pathway was not engaged in wild-type C. reinhardtii, the only algal strain that possessed both cytochrome and alternative pathway capacities. PMID:16667462

  19. Mechanisms of respiration intensification of rat pancreatic acini upon carbachol-induced Ca(2+) release.

    PubMed

    Manko, B O; Manko, V V

    2013-08-01

    Acetylcholine as one of the main secretagogues modulates mitochondrial functions in acinar pancreacytes, presumably due to increase in ATP hydrolysis or Ca(2+) transport into mitochondria. The aim of this work was to investigate the mechanisms of carbachol (CCh) action on respiration and oxidative phosphorylation of isolated pancreatic acini. Respiration of intact or permeabilized rat pancreatic acini was studied at 37 °C using a Clark oxygen electrode. Respiration rate of isolated acini in rest was 0.27 ± 0.01 nmol O2 s(-1) 10(-6) cells. Addition of 10 μM CCh into respiration chamber evoked biphasic stimulation of respiration. Rapid increase of respiration by 20.1% lasted for approx. 1 min, followed by decrease to level by 11.5% higher than control. Addition of 1 μm CCh caused monophasic increase by 11.5%. Preincubation (5 min) with 1 or 10 μm CCh elevated respiration rate by 12.5 or 11.2% respectively. FCCP prevented the effect of CCh. Preincubation with 1 (but not 10) μm CCh increased FCCP-uncoupled respiration rate. Thapsigargin slightly elevated respiration, but ryanodine did not. Application of 2-aminoethoxydiphenyl borate or ruthenium red prevented the effects of CCh on respiration, while oligomycin abolished them. Preincubation with 1 μm CCh prior to cell permeabilization increased respiration rate at pyruvate+malate oxidation, but not at succinate oxidation. In contrast, preincubation with 10 μm CCh decreased pyruvate+malate oxidation. Medium CCh dose (1 μm) intensifies respiration and oxidative phosphorylation of acinar pancreacytes by feedforward mechanism via Ca(2+) transport into mitochondria and activation of Ca(2+) /ADP-sensitive mitochondrial dehydrogenases. Prolonged action of high CCh dose (10 μm) might impair mitochondrial functions. © 2013 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  20. Gastrocnemius mitochondrial respiration: are there any differences between men and women?

    PubMed

    Thompson, Jonathan R; Swanson, Stanley A; Casale, George P; Johanning, Jason M; Papoutsi, Evlampia; Koutakis, Panagiotis; Miserlis, Dimitrios; Zhu, Zhen; Pipinos, Iraklis I

    2013-11-01

    Work on human and mouse skeletal muscle by our group and others has demonstrated that aging and age-related degenerative diseases are associated with mitochondrial dysfunction, which may be more prevalent in males. There have been, however, no studies that specifically examine the influence of male or female sex on human skeletal muscle mitochondrial respiration. The purpose of this study was to compare mitochondrial respiration in the gastrocnemius of adult men and women. Gastrocnemius muscle was obtained from male (n = 19) and female (n = 11) human subjects with healthy lower-extremity musculoskeletal and arterial systems and normal ambulatory function. All patients were undergoing operations for the treatment of varicose veins in their legs. Mitochondrial respiration was determined with a Clark electrode in an oxygraph cell containing saponin-skinned muscle bundles. Complex I-, II-, III-, and IV-dependent respiration was measured individually and normalized to muscle weight, total protein content, and citrate synthase (CS, index of mitochondrial content). Male and female patients had no evidence of musculoskeletal or arterial disease and did not differ with regard to age, race, body mass index, or other clinical characteristics. Complex I-, II-, III-, and IV-dependent respiration normalized to muscle weight, total protein content, and CS did not statistically differ for males compared with females. Our study evaluates, for the first time, gastrocnemius mitochondrial respiration of adult men and women who have healthy musculoskeletal and arterial systems and normal ambulatory function. Our data demonstrate there are no differences in the respiration of gastrocnemius mitochondria between men and women. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Amplification and dampening of soil respiration by changes in temperature variability

    USGS Publications Warehouse

    Sierra, C.A.; Harmon, M.E.; Thomann, E.; Perakis, S.S.; Loescher, H.W.

    2011-01-01

    Accelerated release of carbon from soils is one of the most important feed backs related to anthropogenically induced climate change. Studies addressing the mechanisms for soil carbon release through organic matter decomposition have focused on the effect of changes in the average temperature, with little attention to changes in temperature vari-ability. Anthropogenic activities are likely to modify both the average state and the variability of the climatic system; therefore, the effects of future warming on decomposition should not only focus on trends in the average temperature, but also variability expressed as a change of the probability distribution of temperature.Using analytical and numerical analyses we tested common relationships between temperature and respiration and found that the variability of temperature plays an important role determining respiration rates of soil organic matter. Changes in temperature variability, without changes in the average temperature, can affect the amount of carbon released through respiration over the long term. Furthermore, simultaneous changes in the average and variance of temperature can either amplify or dampen there release of carbon through soil respiration as climate regimes change. The effects depend on the degree of convexity of the relationship between temperature and respiration and the magnitude of the change in temperature variance. A potential consequence of this effect of variability would be higher respiration in regions where both the mean and variance of temperature are expected to increase, such as in some low latitude regions; and lower amounts of respiration where the average temperature is expected to increase and the variance to decrease, such as in northern high latitudes.

  2. Airborne particulate in Varanasi over middle Indo-Gangetic Plain: variation in particulate types and meteorological influences.

    PubMed

    Murari, Vishnu; Kumar, Manish; Mhawish, Alaa; Barman, S C; Banerjee, Tirthankar

    2017-04-01

    The variation in particulate mass and particulate types (PM 2.5 and PM 10 ) with respect to local/regional meteorology was analyzed from January to December 2014 (n = 104) for an urban location over the middle Indo-Gangetic Plain (IGP). Both coarser (mean ± SD; PM 10 161.3 ± 110.4 μg m -3 , n = 104) and finer particulates (PM 2.5 81.78 ± 66.4 μg m -3 ) revealed enormous mass loading with distinct seasonal effects (range: PM 10 12-535 μg m -3 ; PM 2.5 8-362 μg m -3 ). Further, 56% (for PM 2.5 ) to 81% (for PM 10 ) of monitoring events revealed non-attainment national air quality standard especially during winter months. Particulate types (in terms of PM 2.5 /PM 10 0.49 ± 0.19) also exhibited temporal variations with high PM 2.5 loading particularly during winter (0.62) compared to summer months (0.38). Local meteorology has clear distinguishing trends in terms of dry summer (March to June), wet winter (December to February), and monsoon (July to September). Among all the meteorological variables (average temperature, rainfall, relative humidity (RH), wind speed (WS)), temperature was found to be inversely related with particulate loading (r PM10 -0.79; r PM2.5 -0.87) while RH only resulted a significant association with PM 2.5 during summer (r PM10 0.07; r PM2.5 0.55) and with PM 10 during winter (r PM10 0.53; r PM2.5 0.24). Temperature, atmospheric boundary layer (ABL), and RH were cumulatively recognized as the dominant factors regulating particulate concentration as days with high particulate loading (PM 2.5 >150 μg m -3 ; PM 10 >260 μg m -3 ) appeared to have lower ABL (mean 660 m), minimum temperature (<22.6 °C), and high RH (∼79%). The diurnal variations of particulate ratio were mostly insignificant except minor increases during night having a high wintertime ratio (0.58 ± 0.07) over monsoon (0.34 ± 0.05) and summer (0.30 ± 0.07). Across the region, atmospheric visibility appeared to be inversely associated with

  3. Determination of pressure drop across activated carbon fiber respirator cartridges.

    PubMed

    Balanay, Jo Anne G; Lungu, Claudiu T

    2016-01-01

    Activated carbon fiber (ACF) is considered as an alternative adsorbent to granular activated carbon (GAC) for the development of thinner, lighter, and efficient respirators because of their larger surface area and adsorption capacities, thinner critical bed depth, lighter weight, and fabric form. This study aims to measure the pressure drop across different types of commercially available ACFs in respirator cartridges to determine the ACF composition and density that will result in acceptably breathable respirators. Seven ACF types in cloth (ACFC) and felt (ACFF) forms were tested. ACFs in cartridges were challenged with pre-conditioned constant air flow (43 LPM, 23°C, 50% RH) at different compositions (single- or combination-ACF type) in a test chamber. Pressure drop across ACF cartridges were obtained using a micromanometer, and compared among different cartridge configurations, to those of the GAC cartridge, and to the NIOSH breathing resistance requirements for respirator cartridges. Single-ACF type cartridges filled with any ACFF had pressure drop measurements (23.71-39.93 mmH2O) within the NIOSH inhalation resistance requirement of 40 mmH2O, while those of the ACFC cartridges (85.47±3.67 mmH2O) exceeded twice the limit due possibly to the denser weaving of ACFC fibers. All single ACFF-type cartridges had higher pressure drop compared to the GAC cartridge (23.13±1.14 mmH2O). Certain ACF combinations (2 ACFF or ACFC/ACFF types) resulted to pressure drop (26.39-32.81 mmH2O) below the NIOSH limit. All single-ACFF type and all combination-ACF type cartridges with acceptable pressure drop had much lower adsorbent weights than GAC (≤15.2% of GAC weight), showing potential for light-weight respirator cartridges. 100% ACFC in cartridges may result to respirators with high breathing resistance and, thus, is not recommended. The more dense ACFF and ACFC types may still be possibly used in respirators by combining them with less dense ACFF materials and/or by

  4. 42 CFR 84.137 - Inhalation and exhalation valves; check valves; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY... constructed to allow airflow toward the facepiece only shall be provided in the connections to the facepiece...

  5. 42 CFR 84.137 - Inhalation and exhalation valves; check valves; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY... constructed to allow airflow toward the facepiece only shall be provided in the connections to the facepiece...

  6. Contribution of aboveground plant respiration to carbon cycling in a Bornean tropical rainforet

    NASA Astrophysics Data System (ADS)

    Katayama, Ayumi; Tanaka, Kenzo; Ichie, Tomoaki; Kume, Tomonori; Matsumoto, Kazuho; Ohashi, Mizue; Kumagai, Tomo'omi

    2014-05-01

    Bornean tropical rainforests have a different characteristic from Amazonian tropical rainforests, that is, larger aboveground biomass caused by higher stand density of large trees. Larger biomass may cause different carbon cycling and allocation pattern. However, there are fewer studies on carbon allocation and each component in Bornean tropical rainforests, especially for aboveground plant respiration, compared to Amazonian forests. In this study, we measured woody tissue respiration and leaf respiration, and estimated those in ecosystem scale in a Bornean tropical rainforest. Then, we examined carbon allocation using the data of soil respiration and aboveground net primary production obtained from our previous studies. Woody tissue respiration rate was positively correlated with diameter at breast height (dbh) and stem growth rate. Using the relationships and biomass data, we estimated woody tissue respiration in ecosystem scale though methods of scaling resulted in different estimates values (4.52 - 9.33 MgC ha-1 yr-1). Woody tissue respiration based on surface area (8.88 MgC ha-1 yr-1) was larger than those in Amazon because of large aboveground biomass (563.0 Mg ha-1). Leaf respiration rate was positively correlated with height. Using the relationship and leaf area density data at each 5-m height, leaf respiration in ecosystem scale was estimated (9.46 MgC ha-1 yr-1), which was similar to those in Amazon because of comparable LAI (5.8 m2 m-2). Gross primary production estimated from biometric measurements (44.81 MgC ha-1 yr-1) was much higher than those in Amazon, and more carbon was allocated to woody tissue respiration and total belowground carbon flux. Large tree with dbh > 60cm accounted for about half of aboveground biomass and aboveground biomass increment. Soil respiration was also related to position of large trees, resulting in high soil respiration rate in this study site. Photosynthesis ability of top canopy for large trees was high and leaves for

  7. Metabolic changes associated with elevated respiration rate in stored sugarbeet roots after injury

    USDA-ARS?s Scientific Manuscript database

    Although respiration is estimated to cause 60 to 80% of the sucrose loss that occurs during storage, the mechanisms controlling sugarbeet root respiration rate are unknown. Previous research suggested that sugarbeet root respiration was limited by the availability of respiratory substrates, which a...

  8. Glycolysis is dynamic and relates closely to respiration rate in stored sugarbeet roots

    USDA-ARS?s Scientific Manuscript database

    Although respiration is the principal cause of postharvest sugarbeet (Beta vulgaris L.) sucrose loss, the internal mechanisms that control sugarbeet root respiration have not been established. Available evidence, however, indicates that respiration is likely to be controlled by the availability of r...

  9. Identification of anaerobic selenate-respiring bacteria from aquatic sediments.

    PubMed

    Narasingarao, Priya; Häggblom, Max M

    2007-06-01

    The diversity population of microorganisms with the capability to use selenate as a terminal electron acceptor, reducing it to selenite and elemental selenium by the process known as dissimilatory selenate reduction, is largely unknown. The overall objective of this study was to gain an in-depth understanding of anaerobic biotransformation of selenium in the environment, particularly anaerobic respiration, and to characterize the microorganisms catalyzing this process. Here, we demonstrate the isolation and characterization of four novel anaerobic dissimilatory selenate-respiring bacteria enriched from a variety of sources, including sediments from three different water bodies in Chennai, India, and a tidal estuary in New Jersey. Strains S5 and S7 from India, strain KM from the Meadowlands, NJ, and strain pn1, categorized as a laboratory contaminant, were all phylogenetically distinct, belonging to various phyla in the bacterial domain. The 16S rRNA gene sequence shows that strain S5 constitutes a new genus belonging to Chrysiogenetes, while strain S7 belongs to the Deferribacteres, with greater than 98% 16S rRNA gene similarity to Geovibrio ferrireducens. Strain KM is related to Malonomonas rubra, Pelobacter acidigallici, and Desulfuromusa spp., with 96 to 97% 16S rRNA gene similarity. Strain pn1 is 99% similar to Pseudomonas stutzeri. Strains S5, S7, and KM are obligately anaerobic selenate-respiring microorganisms, while strain pn1 is facultatively anaerobic. Besides respiring selenate, all these strains also respire nitrate.

  10. Electrically heated particulate filter propagation support methods and systems

    DOEpatents

    Gonze, Eugene V [Pinckney, MI; Ament, Frank [Troy, MI

    2011-06-07

    A control system that controls regeneration of a particulate filter is provided. The system generally includes a regeneration module that controls current to the particulate filter to initiate combustion of particulate matter in the particulate filter. A propagation module estimates a propagation status of the combustion of the particulate matter based on a combustion temperature. A temperature adjustment module controls the combustion temperature by selectively increasing a temperature of exhaust that passes through the particulate filter.

  11. Soil respiration across a permafrost transition zone: spatial structure and environmental correlates

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stegen, James C.; Anderson, Carolyn G.; Bond-Lamberty, Ben

    Soil respiration is a key ecosystem function whereby shifts in respiration rates can shift systems from carbon sinks to sources. Soil respiration in permafrost-associated systems is particularly important given climate change driven permafrost thaw that leads to significant uncertainty in resulting ecosystem carbon dynamics. Here we characterize the spatial structure and environmental drivers of soil respiration across a permafrost transition zone. We find that soil respiration is characterized by a non-linear threshold that occurs at active-layer depths greater than 140 cm. We also find that within each season, tree basal area is a dominant driver of soil respiration regardless of spatial scale, but onlymore » in spatial domains with significant spatial variability in basal area. Our analyses further show that spatial variation (the coefficient of variation) and mean-variance power-law scaling of soil respiration in our boreal system are consistent with previous work in other ecosystems (e.g., tropical forests) and in population ecology, respectively. Comparing our results to those in other ecosystems suggests that temporally stable features such as tree-stand structure are often primary drivers of spatial variation in soil respiration. If so, this provides an opportunity to better estimate the magnitude and spatial variation in soil respiration through remote sensing. Finally, combining such an approach with broader knowledge of thresholding behavior – here related to active layer depth – would provide empirical constraints on models aimed at predicting ecosystem responses to ongoing permafrost thaw.« less

  12. Soil respiration across a permafrost transition zone: spatial structure and environmental correlates

    DOE PAGES

    Stegen, James C.; Anderson, Carolyn G.; Bond-Lamberty, Ben; ...

    2017-09-28

    Soil respiration is a key ecosystem function whereby shifts in respiration rates can shift systems from carbon sinks to sources. Soil respiration in permafrost-associated systems is particularly important given climate change driven permafrost thaw that leads to significant uncertainty in resulting ecosystem carbon dynamics. Here we characterize the spatial structure and environmental drivers of soil respiration across a permafrost transition zone. We find that soil respiration is characterized by a non-linear threshold that occurs at active-layer depths greater than 140 cm. We also find that within each season, tree basal area is a dominant driver of soil respiration regardless of spatial scale, but onlymore » in spatial domains with significant spatial variability in basal area. Our analyses further show that spatial variation (the coefficient of variation) and mean-variance power-law scaling of soil respiration in our boreal system are consistent with previous work in other ecosystems (e.g., tropical forests) and in population ecology, respectively. Comparing our results to those in other ecosystems suggests that temporally stable features such as tree-stand structure are often primary drivers of spatial variation in soil respiration. If so, this provides an opportunity to better estimate the magnitude and spatial variation in soil respiration through remote sensing. Finally, combining such an approach with broader knowledge of thresholding behavior – here related to active layer depth – would provide empirical constraints on models aimed at predicting ecosystem responses to ongoing permafrost thaw.« less

  13. Soil Respiration in Different Agricultural and Natural Ecosystems in an Arid Region

    PubMed Central

    Lai, Liming; Zhao, Xuechun; Jiang, Lianhe; Wang, Yongji; Luo, Liangguo; Zheng, Yuanrun; Chen, Xi; Rimmington, Glyn M.

    2012-01-01

    The variation of different ecosystems on the terrestrial carbon balance is predicted to be large. We investigated a typical arid region with widespread saline/alkaline soils, and evaluated soil respiration of different agricultural and natural ecosystems. Soil respiration for five ecosystems together with soil temperature, soil moisture, soil pH, soil electric conductivity and soil organic carbon content were investigated in the field. Comparing with the natural ecosystems, the mean seasonal soil respiration rates of the agricultural ecosystems were 96%–386% higher and agricultural ecosystems exhibited lower CO2 absorption by the saline/alkaline soil. Soil temperature and moisture together explained 48%, 86%, 84%, 54% and 54% of the seasonal variations of soil respiration in the five ecosystems, respectively. There was a significant negative relationship between soil respiration and soil electrical conductivity, but a weak correlation between soil respiration and soil pH or soil organic carbon content. Our results showed that soil CO2 emissions were significantly different among different agricultural and natural ecosystems, although we caution that this was an observational, not manipulative, study. Temperature at the soil surface and electric conductivity were the main driving factors of soil respiration across the five ecosystems. Care should be taken when converting native vegetation into cropland from the point of view of greenhouse gas emissions. PMID:23082234

  14. Powder and particulate production of metallic alloys

    NASA Technical Reports Server (NTRS)

    Grant, N. J.

    1982-01-01

    Developments of particulate metallurgy of alloyed materials where the final products is a fully dense body are discussed. Particulates are defined as powders, flakes, foils, silvers, ribbons and strip. Because rapid solidification is an important factor in particulate metallurgy, all of the particulates must have at least one dimension which is very fine, sometimes as fine as 10 to 50 microns, but move typically up to several hundred microns, provided that the dimension permits a minimum solidification rate of at least 100 K/s.

  15. Electrically heated particulate filter embedded heater design

    DOEpatents

    Gonze, Eugene V.; Chapman, Mark R.

    2014-07-01

    An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine and wherein an upstream surface of the particulate filter includes machined grooves. A grid of electrically resistive material is inserted into the machined grooves of the exterior upstream surface of the PF and selectively heats exhaust passing through the grid to initiate combustion of particulates within the PF.

  16. Apnea Detection Method for Cheyne-Stokes Respiration Analysis on Newborn

    NASA Astrophysics Data System (ADS)

    Niimi, Taiga; Itoh, Yushi; Natori, Michiya; Aoki, Yoshimitsu

    2013-04-01

    Cheyne-Stokes respiration is especially prevalent in preterm newborns, but its severity may not be recognized. It is characterized by apnea and cyclical weakening and strengthening of the breathing. We developed a method for detecting apnea and this abnormal respiration and for estimating its malignancy. Apnea was detected based on a "difference" feature (calculated from wavelet coefficients) and a modified maximum displacement feature (related to the respiratory waveform shape). The waveform is calculated from vertical motion of the thoracic and abdominal region during respiration using a vision sensor. Our proposed detection method effectively detects apnea (sensitivity 88.4%, specificity 99.7%).

  17. Acclimation and soil moisture constrain sugar maple root respiration in experimentally warmed soil.

    PubMed

    Jarvi, Mickey P; Burton, Andrew J

    2013-09-01

    The response of root respiration to warmer soil can affect ecosystem carbon (C) allocation and the strength of positive feedbacks between climatic warming and soil CO2 efflux. This study sought to determine whether fine-root (<1 mm) respiration in a sugar maple (Acer saccharum Marsh.)-dominated northern hardwood forest would adjust to experimentally warmed soil, reducing C return to the atmosphere at the ecosystem scale to levels lower than that would be expected using an exponential temperature response function. Infrared heating lamps were used to warm the soil (+4 to +5 °C) in a mature sugar maple forest in a fully factorial design, including water additions used to offset the effects of warming-induced dry soil. Fine-root-specific respiration rates, root biomass, root nitrogen (N) concentration, soil temperature and soil moisture were measured from 2009 to 2011, with experimental treatments conducted from late 2010 to 2011. Partial acclimation of fine-root respiration to soil warming occurred, with soil moisture deficit further constraining specific respiration rates in heated plots. Fine-root biomass and N concentration remained unchanged. Over the 2011 growing season, ecosystem root respiration was not significantly greater in warmed soil. This result would not be predicted by models that allow respiration to increase exponentially with temperature and do not directly reduce root respiration in drier soil.

  18. Respiration climacteric in tomato fruits elucidated by constraint-based modelling.

    PubMed

    Colombié, Sophie; Beauvoit, Bertrand; Nazaret, Christine; Bénard, Camille; Vercambre, Gilles; Le Gall, Sophie; Biais, Benoit; Cabasson, Cécile; Maucourt, Mickaël; Bernillon, Stéphane; Moing, Annick; Dieuaide-Noubhani, Martine; Mazat, Jean-Pierre; Gibon, Yves

    2017-03-01

    Tomato is a model organism to study the development of fleshy fruit including ripening initiation. Unfortunately, few studies deal with the brief phase of accelerated ripening associated with the respiration climacteric because of practical problems involved in measuring fruit respiration. Because constraint-based modelling allows predicting accurate metabolic fluxes, we investigated the respiration and energy dissipation of fruit pericarp at the breaker stage using a detailed stoichiometric model of the respiratory pathway, including alternative oxidase and uncoupling proteins. Assuming steady-state, a metabolic dataset was transformed into constraints to solve the model on a daily basis throughout tomato fruit development. We detected a peak of CO 2 released and an excess of energy dissipated at 40 d post anthesis (DPA) just before the onset of ripening coinciding with the respiration climacteric. We demonstrated the unbalanced carbon allocation with the sharp slowdown of accumulation (for syntheses and storage) and the beginning of the degradation of starch and cell wall polysaccharides. Experiments with fruits harvested from plants cultivated under stress conditions confirmed the concept. We conclude that modelling with an accurate metabolic dataset is an efficient tool to bypass the difficulty of measuring fruit respiration and to elucidate the underlying mechanisms of ripening. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  19. Modelling the influence of time and temperature on the respiration rate of fresh oyster mushrooms.

    PubMed

    Azevedo, Sílvia; Cunha, Luís M; Fonseca, Susana C

    2015-12-01

    The respiration rate of mushrooms is an important indicator of postharvest senescence. Storage temperature plays a major role in their rate of respiration and, therefore, in their postharvest life. In this context, reliable predictions of respiration rates are critical for the development of modified atmosphere packaging that ultimately will maximise the quality of the product to be presented to consumers. This work was undertaken to study the influence of storage time and temperature on the respiration rate of oyster mushrooms. For that purpose, oyster mushrooms were stored at constant temperatures of 2, 6, 10, 14 and 18 ℃ under ambient atmosphere. Respiration rate data were measured with 8-h intervals up to 240 h. A decrease of respiration rate was found after cutting of the carpophores. Therefore, time effect on respiration rate was modelled using a first-order decay model. The results also show the positive influence of temperature on mushroom respiration rate. The model explaining the effect of time on oyster mushroom's respiration rate included the temperature dependence according to the Arrhenius equation, and the inclusion of a parameter describing the decrease of the respiration rate, from the initial time until equilibrium. These yielded an overall model that fitted well to the experimental data. Moreover, results show that the overall model is useful to predict respiration rate of oyster mushrooms at different temperatures and times, using the initial respiration rate of mushrooms. Furthermore, predictive modelling can be relevant for the choice of an appropriate packaging system for fresh oyster mushrooms. © The Author(s) 2014.

  20. Measurement and Modeling of Respiration Rate of Tomato (Cultivar Roma) for Modified Atmosphere Storage.

    PubMed

    Kandasamy, Palani; Moitra, Ranabir; Mukherjee, Souti

    2015-01-01

    Experiments were conducted to determine the respiration rate of tomato at 10, 20 and 30 °C using closed respiration system. Oxygen depletion and carbon dioxide accumulation in the system containing tomato was monitored. Respiration rate was found to decrease with increasing CO2 and decreasing O2 concentration. Michaelis-Menten type model based on enzyme kinetics was evaluated using experimental data generated for predicting the respiration rate. The model parameters that obtained from the respiration rate at different O2 and CO2 concentration levels were used to fit the model against the storage temperatures. The fitting was fair (R2 = 0.923 to 0.970) when the respiration rate was expressed as O2 concentation. Since inhibition constant for CO2 concentration tended towards negetive, the model was modified as a function of O2 concentration only. The modified model was fitted to the experimental data and showed good agreement (R2 = 0.998) with experimentally estimated respiration rate.

  1. Pinus sylvestris switches respiration substrates under shading but not during drought.

    PubMed

    Fischer, Sarah; Hanf, Stefan; Frosch, Torsten; Gleixner, Gerd; Popp, Jürgen; Trumbore, Susan; Hartmann, Henrik

    2015-08-01

    Reduced carbon (C) assimilation during prolonged drought forces trees to rely on stored C to maintain vital processes like respiration. It has been shown, however, that the use of carbohydrates, a major C storage pool and apparently the main respiratory substrate in plants, strongly declines with decreasing plant hydration. Yet no empirical evidence has been produced to what degree other C storage compounds like lipids and proteins may fuel respiration during drought. We exposed young scots pine trees to C limitation using either drought or shading and assessed respiratory substrate use by monitoring the respiratory quotient, δ(13) C of respired CO2 and concentrations of the major storage compounds, that is, carbohydrates, lipids and amino acids. Only shaded trees shifted from carbohydrate-dominated to lipid-dominated respiration and showed progressive carbohydrate depletion. In drought trees, the fraction of carbohydrates used in respiration did not decline but respiration rates were strongly reduced. The lower consumption and potentially allocation from other organs may have caused initial carbohydrate content to remain constant during the experiment. Our results suggest that respiratory substrates other than carbohydrates are used under carbohydrate limitation but not during drought. Thus, respiratory substrate shift cannot provide an efficient means to counterbalance C limitation under natural drought. © 2015 The Authors New Phytologist © 2015 New Phytologist Trust.

  2. Pinus sylvestris switches respiration substrates under shading but not during drought

    NASA Astrophysics Data System (ADS)

    Hartmann, Henrik; Fischer, Sarah; Hanf, Stefan; Frosch, Torsten; Poppp, Jürgen; Trumbore, Susan

    2015-04-01

    Reduced carbon assimilation during prolonged drought forces trees to rely on stored carbon to maintain vital processes like respiration. It has been shown, however, that the use of carbohydrates, a major carbon storage pool and main respiratory substrate in plants, strongly declines with deceasing plant hydration. Yet, no empirical evidence has been produced to what degree other carbon storage compounds like lipids and proteins may fuel respiration during drought. We exposed young scots pine trees to carbon limitation using either drought or shading and assessed respiratory substrate use by monitoring the respiratory quotient, δ13C of respired CO2and concentrations of the major storage compounds, i.e. carbohydrates (COH), lipids and amino acids. Generally, respiration was dominated by the most abundant substrate. Only shaded trees shifted from carbohydrate-dominated to lipid-dominated respiration and showed progressive carbohydrate depletion. In drought trees respiration was strongly reduced and fueled with carbohydrates from also strongly reduced carbon assimilation. Initial COH content was maintained during drought probably due to reduced COH mobilization and use and the maintained COH content may have prevented lipid catabolism via sugar signaling. Our results suggest that respiratory substrates other than carbohydrates are used under carbohydrate limitation but not during drought. Thus, respiratory substrate change cannot provide an efficient means to counterbalance carbon limitation under natural drought.

  3. Electrically heated particulate filter using catalyst striping

    DOEpatents

    Gonze, Eugene V; Paratore, Jr., Michael J; Ament, Frank

    2013-07-16

    An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine. A grid of electrically resistive material is applied to an exterior upstream surface of the PF and selectively heats exhaust passing through the grid to initiate combustion of particulates within the PF. A catalyst coating is applied to the PF that increases a temperature of the combustion of the particulates within the PF.

  4. Widespread inhibition of day-time ecosystem respiration and implications for eddy-covariance flux partitioning

    NASA Astrophysics Data System (ADS)

    Keenan, T. F.

    2017-12-01

    Global terrestrial ecosystems absorb about a third of anthropogenic emissions each year, due to the difference between two key processes: photosynthesis and respiration. Despite the importance of these two processes at the global scale, no direct measurement exists of either. Eddy-covariance (EC) measurements have been widely used as the closest `quasi-direct' observation, and the resulting estimates have been used to produce global budgets of photosynthesis and respiration. Recent research, however, suggests that current estimates may be biased by up to 25%, as the methods used to partition observed net carbon fluxes to photosynthesis and respiration do not take into account any inhibition of leaf respiration in light. Yet the prevalence of light-inhibition of leaf respiration remains debated, and impacts on global estimates of photosynthesis and respiration unquantified. Here, we use novel approaches to estimate the extent of light-inhibition across the global FLUXNET EC network, and find strong evidence for an inhibition effect on ecosystem respiration, which varies by season and plant functional type. We develop partitioning methods that allow for inhibition, and find that that diurnal patterns of ecosystem respiration might be markedly different than previously thought. The results call for the reevaluation of global terrestrial carbon cycle models, and also suggest that current global budgets of photosynthesis and respiration may be biased on the order of magnitude of anthropogenic fossil fuel emissions.

  5. Cheyne-Stokes respiration in patients with congestive heart failure: causes and consequences.

    PubMed

    Lorenzi-Filho, Geraldo; Genta, Pedro R; Figueiredo, Adelaide C; Inoue, Daniel

    2005-08-01

    Cheyne-Stokes respiration is a form of periodic breathing in which central apneas and hypopneas alternate with periods of hyperventilation, producing a waxing and waning pattern of tidal volume. This review focuses on the causes and consequences of Cheyne-Stokes respiration in patients with congestive heart failure, in whom the prevalence is strikingly high and ranges from 30% to 50%. Several factors have been implicated in the genesis of Cheyne-Stokes respiration, including low cardiac output and recurrent hypoxia. The key pathophysiological mechanism triggering Cheyne-Stokes respiration is hyperventilation and low arterial CO2 (PaCO2) that when below the apneic threshold triggers a central apnea. Hyperventilation is associated with pulmonary congestion, and Cheyne-Stokes respiration is more prone to occur during sleep, when the respiratory system is mainly dependent on chemical control. It is associated with recurrent dips in oxygen saturation and arousals from sleep, with oscillations in blood pressure and heart rate, sympathetic activation and increased risk of ventricular tachycardia. Cheyne-Stokes respiration is an independent marker of poor prognosis and may participate in a vicious cycle, further stressing the failing heart.

  6. The significance of respiration timing in the energetics estimates of free-ranging killer whales (Orcinus orca).

    PubMed

    Roos, Marjoleine M H; Wu, Gi-Mick; Miller, Patrick J O

    2016-07-01

    Respiration rate has been used as an indicator of metabolic rate and associated cost of transport (COT) of free-ranging cetaceans, discounting potential respiration-by-respiration variation in O2 uptake. To investigate the influence of respiration timing on O2 uptake, we developed a dynamic model of O2 exchange and storage. Individual respiration events were revealed from kinematic data from 10 adult Norwegian herring-feeding killer whales (Orcinus orca) recorded with high-resolution tags (DTAGs). We compared fixed O2 uptake per respiration models with O2 uptake per respiration estimated through a simple 'broken-stick' O2-uptake function, in which O2 uptake was assumed to be the maximum possible O2 uptake when stores are depleted or maximum total body O2 store minus existing O2 store when stores are close to saturated. In contrast to findings assuming fixed O2 uptake per respiration, uptake from the broken-stick model yielded a high correlation (r(2)>0.9) between O2 uptake and activity level. Moreover, we found that respiration intervals increased and became less variable at higher swimming speeds, possibly to increase O2 uptake efficiency per respiration. As found in previous studies, COT decreased monotonically versus speed using the fixed O2 uptake per respiration models. However, the broken-stick uptake model yielded a curvilinear COT curve with a clear minimum at typical swimming speeds of 1.7-2.4 m s(-1) Our results showed that respiration-by-respiration variation in O2 uptake is expected to be significant. And though O2 consumption measurements of COT for free-ranging cetaceans remain impractical, accounting for the influence of respiration timing on O2 uptake will lead to more consistent predictions of field metabolic rates than using respiration rate alone. © 2016. Published by The Company of Biologists Ltd.

  7. Inhibitory Effects of Respiration Inhibitors on Aflatoxin Production

    PubMed Central

    Sakuda, Shohei; Prabowo, Diyan Febri; Takagi, Keiko; Shiomi, Kazuro; Mori, Mihoko; Ōmura, Satoshi; Nagasawa, Hiromichi

    2014-01-01

    Aflatoxin production inhibitors, which do not inhibit the growth of aflatoxigenic fungi, may be used to control aflatoxin without incurring a rapid spread of resistant strains. A respiration inhibitor that inhibits aflatoxin production was identified during a screening process for natural, aflatoxin-production inhibitors. This prompted us to evaluate respiration inhibitors as potential aflatoxin control agents. The inhibitory activities of four natural inhibitors, seven synthetic miticides, and nine synthetic fungicides were evaluated on aflatoxin production in Aspergillus parasiticus. All of the natural inhibitors (rotenone, siccanin, aptenin A5, and antimycin A) inhibited fungal aflatoxin production with IC50 values around 10 µM. Among the synthetic miticides, pyridaben, fluacrypyrim, and tolfenpyrad exhibited strong inhibitory activities with IC50 values less than 0.2 µM, whereas cyflumetofen did not show significant inhibitory activity. Of the synthetic fungicides, boscalid, pyribencarb, azoxystrobin, pyraclostrobin, and kresoxim-methyl demonstrated strong inhibitory activities, with IC50 values less than 0.5 µM. Fungal growth was not significantly affected by any of the inhibitors tested at concentrations used. There was no correlation observed between the targets of respiration inhibitors (complexes I, II, and III) and their IC50 values for aflatoxin-production inhibitory activity. This study suggests that respiration inhibitors, including commonly used pesticides, are useful for aflatoxin control. PMID:24674936

  8. Shallow snowpack inhibits soil respiration in sagebrush steppe through multiple biotic and abiotic mechanisms

    DOE PAGES

    Tucker, Colin L.; Tamang, Shanker; Pendall, Elise; ...

    2016-05-01

    In sagebrush steppe, snowpack may govern soil respiration through its effect on multiple abiotic and biotic factors. Across the Intermountain West of the United States, snowpack has been declining for decades and is projected to decline further over the next century, making the response of soil respiration to snowpack a potentially important factor in the ecosystem carbon cycle. In this study, we evaluated the direct and indirect roles of the snowpack in driving soil respiration in sagebrush steppe ecosystems by taking advantage of highway snowfences in Wyoming to manipulate snowpack. An important contribution of this study is the use ofmore » Bayesian modeling to quantify the effects of soil moisture and temperature on soil respiration across a wide range of conditions from frozen to hot and dry, while simultaneously accounting for biotic factors (e.g., vegetation cover, root density, and microbial biomass and substrate-use diversity) affected by snowpack. Elevated snow depth increased soil temperature (in the winter) and moisture (winter and spring), and was associated with reduced vegetation cover and microbial biomass carbon. Soil respiration showed an exponential increase with temperature, with a temperature sensitivity that decreased with increasing seasonal temperature (Q 10 = 4.3 [winter], 2.3 [spring], and 1.7 [summer]); frozen soils were associated with unrealistic Q 10 approximate to 7989 due to the liquid-to-ice transition of soil water. Soil respiration was sensitive to soil water content; predicted respiration under very dry conditions was less than 10% of respiration under moist conditions. While higher vegetation cover increased soil respiration, this was not due to increased root density, and may reflect differences in litter inputs. Microbial substrate-use diversity was negatively related to reference respiration (i.e., respiration rate at a reference temperature and optimal soil moisture), although the mechanism remains unclear. Lastly, this

  9. Shallow snowpack inhibits soil respiration in sagebrush steppe through multiple biotic and abiotic mechanisms

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tucker, Colin L.; Tamang, Shanker; Pendall, Elise

    In sagebrush steppe, snowpack may govern soil respiration through its effect on multiple abiotic and biotic factors. Across the Intermountain West of the United States, snowpack has been declining for decades and is projected to decline further over the next century, making the response of soil respiration to snowpack a potentially important factor in the ecosystem carbon cycle. In this study, we evaluated the direct and indirect roles of the snowpack in driving soil respiration in sagebrush steppe ecosystems by taking advantage of highway snowfences in Wyoming to manipulate snowpack. An important contribution of this study is the use ofmore » Bayesian modeling to quantify the effects of soil moisture and temperature on soil respiration across a wide range of conditions from frozen to hot and dry, while simultaneously accounting for biotic factors (e.g., vegetation cover, root density, and microbial biomass and substrate-use diversity) affected by snowpack. Elevated snow depth increased soil temperature (in the winter) and moisture (winter and spring), and was associated with reduced vegetation cover and microbial biomass carbon. Soil respiration showed an exponential increase with temperature, with a temperature sensitivity that decreased with increasing seasonal temperature (Q 10 = 4.3 [winter], 2.3 [spring], and 1.7 [summer]); frozen soils were associated with unrealistic Q 10 approximate to 7989 due to the liquid-to-ice transition of soil water. Soil respiration was sensitive to soil water content; predicted respiration under very dry conditions was less than 10% of respiration under moist conditions. While higher vegetation cover increased soil respiration, this was not due to increased root density, and may reflect differences in litter inputs. Microbial substrate-use diversity was negatively related to reference respiration (i.e., respiration rate at a reference temperature and optimal soil moisture), although the mechanism remains unclear. Lastly, this

  10. Effects of long-term microgravitation exposure on cell respiration of the rat musculus soleus fibers.

    PubMed

    Veselova, O M; Ogneva, I V; Larina, I M

    2011-07-01

    Cell respiration of the m. soleus fibers was studied in Wistar rats treated with succinic acid and exposed to microgravitation for 35 days. The results indicated that respiration rates during utilization of endogenous and exogenous substrates and the maximum respiration rate decreased in animals subjected to microgravitation without succinate treatment. The respiration rate during utilization of exogenous substrate did not increase in comparison with that on endogenous substrates. Succinic acid prevented the decrease in respiration rate on endogenous substrates and the maximum respiration rate. On the other hand, the respiration rate on exogenous substrates was reduced in vivarium control rats receiving succinate in comparison with intact control group. That could indicate changed efficiency of complex I of the respiratory chain due to reciprocal regulation of the tricarbonic acid cycle.

  11. Micromechanics for particulate reinforced composites

    NASA Technical Reports Server (NTRS)

    Murthy, Pappu L. N.; Goldberg, Robert K.; Mital, Subodh K.

    1996-01-01

    A set of micromechanics equations for the analysis of particulate reinforced composites is developed using the mechanics of materials approach. Simplified equations are used to compute homogenized or equivalent thermal and mechanical properties of particulate reinforced composites in terms of the properties of the constituent materials. The microstress equations are also presented here to decompose the applied stresses on the overall composite to the microstresses in the constituent materials. The properties of a 'generic' particulate composite as well as those of a particle reinforced metal matrix composite are predicted and compared with other theories as well as some experimental data. The micromechanics predictions are in excellent agreement with the measured values.

  12. Evaluation of breathing patterns for respiratory-gated radiation therapy using the respiration regularity index

    NASA Astrophysics Data System (ADS)

    Cheong, Kwang-Ho; Lee, MeYeon; Kang, Sei-Kwon; Yoon, Jai-Woong; Park, SoAh; Hwang, Taejin; Kim, Haeyoung; Kim, KyoungJu; Han, Tae Jin; Bae, Hoonsik

    2015-01-01

    Despite the considerable importance of accurately estimating the respiration regularity of a patient in motion compensation treatment, not to mention the necessity of maintaining that regularity through the following sessions, an effective and simply applicable method by which those goals can be accomplished has rarely been reported. The authors herein propose a simple respiration regularity index based on parameters derived from a correspondingly simplified respiration model. In order to simplify a patient's breathing pattern while preserving the data's intrinsic properties, we defined a respiration model as a cos4( ω( t) · t) wave form with a baseline drift. According to this respiration formula, breathing-pattern fluctuation could be explained using four factors: the sample standard deviation of respiration period ( s f ), the sample standard deviation of amplitude ( s a ) and the results of a simple regression of the baseline drift (slope as β, and standard deviation of residuals as σ r ) of a respiration signal. The overall irregularity ( δ) was defined as , where is a variable newly-derived by using principal component analysis (PCA) for the four fluctuation parameters and has two principal components ( ω 1, ω 2). The proposed respiration regularity index was defined as ρ = ln(1 + (1/ δ))/2, a higher ρ indicating a more regular breathing pattern. We investigated its clinical relevance by comparing it with other known parameters. Subsequently, we applied it to 110 respiration signals acquired from five liver and five lung cancer patients by using real-time position management (RPM; Varian Medical Systems, Palo Alto, CA). Correlations between the regularity of the first session and the remaining fractions were investigated using Pearson's correlation coefficient. Additionally, the respiration regularity was compared between the liver and lung cancer patient groups. The respiration regularity was determined based on ρ; patients with ρ < 0.3 showed

  13. Influence of continuous mining arrangements on respirable dust exposures

    PubMed Central

    Beck, T. W.; Organiscak, J. A.; Pollock, D. E.; Potts, J. D.; Reed, W. R.

    2017-01-01

    In underground continuous mining operations, ventilation, water sprays and machine-mounted flooded-bed scrubbers are the primary means of controlling respirable dust exposures at the working face. Changes in mining arrangements — such as face ventilation configuration, orientation of crosscuts mined in relation to the section ventilation and equipment operator positioning — can have impacts on the ability of dust controls to reduce occupational respirable dust exposures. This study reports and analyzes dust concentrations measured by the Pittsburgh Mining Research Division for remote-controlled continuous mining machine operators as well as haulage operators at 10 U.S. underground mines. The results of these respirable dust surveys show that continuous miner exposures varied little with depth of cut but are significantly higher with exhaust ventilation. Haulage operators experienced elevated concentrations with blowing face ventilation. Elevated dust concentrations were observed for both continuous miner operators and haulage operators when working in crosscuts driven into or counter to the section airflow. Individual cuts are highlighted to demonstrate instances of minimal and excessive dust exposures attributable to particular mining configurations. These findings form the basis for recommendations for lowering face worker respirable dust exposures. PMID:28529441

  14. Assessment of patients' experience of discomforts during respirator therapy.

    PubMed

    Bergbom-Engberg, I; Haljamäe, H

    1989-10-01

    Patients (n = 158) who had been respirator-treated and who could remember the treatment were retrospectively (after greater than 2 months) interviewed about their experiences. Of all patients, 47% had felt anxiety and/or fear during the treatment. These feelings were intimately related to the experience of agony/panic (p less than .001) and insecurity (p less than .001). Inability to talk and communicate was found to be the dominating reason (p less than .001) for evoking such feelings and also made it difficult for the patients to sleep and rest (p less than .05); no correlation to pain was found. Difficulties to synchronize with the respirator in connection with suctioning also caused feelings of anxiety/fear (p less than .01), agony/panic (p less than .01), and insecurity (p less than .001). Even as long as 4 yr after respirator treatment, most patients (90%) who remember the treatment still recall the situation as unpleasant and stress-evoking. The isolation due to communication difficulties was a greater problem than direct airway-related nursing care activities. This relationship between communication difficulties and severe emotional reactions should be considered in the nursing care of respirator-treated patients.

  15. Partitioning Ecosystem Respiration Using Stable Carbon Isotopes in a Mixed C3 Annual Grassland

    NASA Astrophysics Data System (ADS)

    Tu, K. P.

    2001-12-01

    The stable carbon isotope ratio (δ 13C) of respired CO2 has been used to partition soil respiration into root and microbial components by exploiting the different δ 13C signals from C3 plants growing in a previously C4 dominated system (Rouchette, Angers and Flanagan 1999). We extend this approach and present data that attempts to partition ecosystem respiration using δ 13C analyses of all of the ecosystem compartments in a mixed C3 annual grassland that has not experienced recent C4 inputs. From December 2000 to February 2001 we measured δ 13C-CO2 respired from leaves, roots and sieved soil collected from a winter-active grassland near Ione, California. Two-source mixing models were used to calculate the contribution of each source to total system respiration by comparing their isotope signals to those from whole ecosystem respiration and soil surface efflux. Isotope ratios were measured on 10mL air samples in septum-capped vials using a Finnigan MAT Delta PlusXL IRMS/Gas Bench II interfaced to an autosampler (after Tu et al. 2001). The vials were filled with sample air in the field using a double-holed needle connected in a closed loop to a LI-6200 IRGA and a bottle containing the isolated samples (leaf, root, sieved soil, etc.). Leaves were clipped at ground level and roots and soil were separated by sieving soil cores. Sample δ 13CO2 signatures were determined by plotting the change in δ 13C against the inverse of CO2 concentration. On average, CO2 respired from sieved soil (-27.4o/oo+/-1.4) was slightly more depleted than that from leaves (-27.2o/oo+/-0.5), but much more depleted than the whole ecosystem (-24.9o/oo+/-0.6), the soil surface efflux (-23.8o/oo+/-0.9), and plant roots (-20.5o/oo+/-0.8). Based on these isotope values, leaf respiration comprised 33% of ecosystem respiration with 36% from roots and 31% from soil microbial respiration. Thus, over two-thirds of ecosystem respiration was autotrophic (plant-based) in origin with roughly one

  16. Characterization of the respiration-induced yeast mitochondrial permeability transition pore.

    PubMed

    Bradshaw, Patrick C; Pfeiffer, Douglas R

    2013-12-01

    When isolated mitochondria from the yeast Saccharomyces cerevisiae oxidize respiratory substrates in the absence of phosphate and ADP, the yeast mitochondrial unselective channel, also called the yeast permeability transition pore (yPTP), opens in the inner membrane, dissipating the electrochemical gradient. ATP also induces yPTP opening. yPTP opening allows mannitol transport into isolated mitochondria of laboratory yeast strains, but mannitol is not readily permeable through the yPTP in an industrial yeast strain, Yeast Foam. The presence of oligomycin, an inhibitor of ATP synthase, allowed for respiration-induced mannitol permeability in mitochondria from this strain. Potassium (K+) had varied effects on the respiration-induced yPTP, depending on the concentration of the respiratory substrate added. At low respiratory substrate concentrations K+ inhibited respiration-induced yPTP opening, while at high substrate concentrations this effect diminished. However, at the high respiratory substrate concentrations, the presence of K+ partially prevented phosphate inhibition of yPTP opening. Phosphate was found to inhibit respiration-induced yPTP opening by binding a site on the matrix space side of the inner membrane in addition to its known inhibitory effect of donating protons to the matrix space to prevent the pH change necessary for yPTP opening. The respiration-induced yPTP was also inhibited by NAD, Mg2+, NH4 + or the oxyanion vanadate polymerized to decavanadate. The results demonstrate similar effectors of the respiration-induced yPTP as those previously described for the ATP-induced yPTP and reconcile previous strain-dependent differences in yPTP solute selectivity. Copyright © 2013 John Wiley & Sons, Ltd.

  17. Respiration, oxidative phosphorylation, and uncoupling protein in Candida albicans.

    PubMed

    Cavalheiro, R A; Fortes, F; Borecký, J; Faustinoni, V C; Schreiber, A Z; Vercesi, A E

    2004-10-01

    The respiration, membrane potential (Deltapsi), and oxidative phosphorylation of mitochondria in situ were determined in spheroplasts obtained from Candida albicans control strain ATCC 90028 by lyticase treatment. Mitochondria in situ were able to phosphorylate externally added ADP (200 microM) in the presence of 0.05% BSA. Mitochondria in situ generated and sustained stable mitochondrial Deltapsi respiring on 5 mM NAD-linked substrates, 5 mM succinate, or 100 microM N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride plus 1 mM ascorbate. Rotenone (4 microM) inhibited respiration by 30% and 2 micro M antimycin A or myxothiazole and 1 mM cyanide inhibited it by 85%. Cyanide-insensitive respiration was partially blocked by 2 mM benzohydroxamic acid, suggesting the presence of an alternative oxidase. Candida albicans mitochondria in situ presented a carboxyatractyloside-insensitive increase of Deltapsi induced by 5 mM ATP and 0.5% BSA, and Deltapsi decrease induced by 10 microM linoleic acid, both suggesting the existence of an uncoupling protein. The presence of this protein was subsequently confirmed by immunodetection and respiration experiments with isolated mitochondria. In conclusion, Candida albicans ATCC 90028 possesses an alternative electron transfer chain and alternative oxidase, both absent in animal cells. These pathways can be exceptional targets for the design of new chemotherapeutic agents. Blockage of these respiratory pathways together with inhibition of the uncoupling protein (another potential target for drug design) could lead to increased production of reactive oxygen species, dysfunction of Candida mitochondria, and possibly to oxidative cell death.

  18. Redefinition and global estimation of basal ecosystem respiration rate

    NASA Astrophysics Data System (ADS)

    Yuan, Wenping; Luo, Yiqi; Li, Xianglan; Liu, Shuguang; Yu, Guirui; Zhou, Tao; Bahn, Michael; Black, Andy; Desai, Ankur R.; Cescatti, Alessandro; Marcolla, Barbara; Jacobs, Cor; Chen, Jiquan; Aurela, Mika; Bernhofer, Christian; Gielen, Bert; Bohrer, Gil; Cook, David R.; Dragoni, Danilo; Dunn, Allison L.; Gianelle, Damiano; Grünwald, Thomas; Ibrom, Andreas; Leclerc, Monique Y.; Lindroth, Anders; Liu, Heping; Marchesini, Luca Belelli; Montagnani, Leonardo; Pita, Gabriel; Rodeghiero, Mirco; Rodrigues, Abel; Starr, Gregory; Stoy, Paul C.

    2011-12-01

    Basal ecosystem respiration rate (BR), the ecosystem respiration rate at a given temperature, is a common and important parameter in empirical models for quantifying ecosystem respiration (ER) globally. Numerous studies have indicated that BR varies in space. However, many empirical ER models still use a global constant BR largely due to the lack of a functional description for BR. In this study, we redefined BR to be ecosystem respiration rate at the mean annual temperature. To test the validity of this concept, we conducted a synthesis analysis using 276 site-years of eddy covariance data, from 79 research sites located at latitudes ranging from ˜3°S to ˜70°N. Results showed that mean annual ER rate closely matches ER rate at mean annual temperature. Incorporation of site-specific BR into global ER model substantially improved simulated ER compared to an invariant BR at all sites. These results confirm that ER at the mean annual temperature can be considered as BR in empirical models. A strong correlation was found between the mean annual ER and mean annual gross primary production (GPP). Consequently, GPP, which is typically more accurately modeled, can be used to estimate BR. A light use efficiency GPP model (i.e., EC-LUE) was applied to estimate global GPP, BR and ER with input data from MERRA (Modern Era Retrospective-Analysis for Research and Applications) and MODIS (Moderate resolution Imaging Spectroradiometer). The global ER was 103 Pg C yr -1, with the highest respiration rate over tropical forests and the lowest value in dry and high-latitude areas.

  19. Dynamics of enhanced mitochondrial respiration in female compared with male rat cerebral arteries.

    PubMed

    Rutkai, Ibolya; Dutta, Somhrita; Katakam, Prasad V; Busija, David W

    2015-11-01

    Mitochondrial respiration has never been directly examined in intact cerebral arteries. We tested the hypothesis that mitochondrial energetics of large cerebral arteries ex vivo are sex dependent. The Seahorse XFe24 analyzer was used to examine mitochondrial respiration in isolated cerebral arteries from adult male and female Sprague-Dawley rats. We examined the role of nitric oxide (NO) on mitochondrial respiration under basal conditions, using N(ω)-nitro-l-arginine methyl ester, and following pharmacological challenge using diazoxide (DZ), and also determined levels of mitochondrial and nonmitochondrial proteins using Western blot, and vascular diameter responses to DZ. The components of mitochondrial respiration including basal respiration, ATP production, proton leak, maximal respiration, and spare respiratory capacity were elevated in females compared with males, but increased in both male and female arteries in the presence of the NOS inhibitor. Although acute DZ treatment had little effect on mitochondrial respiration of male arteries, it decreased the respiration in female arteries. Levels of mitochondrial proteins in Complexes I-V and the voltage-dependent anion channel protein were elevated in female compared with male cerebral arteries. The DZ-induced vasodilation was greater in females than in males. Our findings show that substantial sex differences in mitochondrial respiratory dynamics exist in large cerebral arteries and may provide the mechanistic basis for observations that the female cerebral vasculature is more adaptable after injury. Copyright © 2015 the American Physiological Society.

  20. Radio Frequency Sensing of Particulate Matter Accumulation on a Gasoline Particulate Filter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Parks, James; Prikhodko, Vitaly Y.; Sappok, Alex

    Filter Sensing Technology’s radio frequency (RF) sensor for particulate filter on-board diagnostics (OBD) was studied on a lean gasoline engine at the National Transportation Research Center (NTRC) at Oak Ridge National Laboratory (ORNL). The response of the RF sensor to particulate matter (PM) or “soot” accumulation on the gasoline particulate filter (GPF) installed in the engine exhaust was evaluated. In addition, end plugs of the GPF were purposely removed, and subsequent changes to the RF sensor measured soot loading on the GPF were characterized. Results from the study showed that the RF sensor can accurately measure soot accumulation on amore » GPF; furthermore, the predicted decreased soot accumulation due to plug removal was detected by the RF sensor. Overall, the studies were short and preliminary in nature; however, clearly, the RF sensor demonstrated the capability of measuring GPF soot loading at a level suitable for use in lean gasoline engine emission control OBD and control.« less

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