New-onset asthma after exposure to the steam system additive 2-diethylaminoethanol. A descriptive study.

PubMed

Gadon, M E; Melius, J M; McDonald, G J; Orgel, D

1994-06-01

Through a leak in the steam heating system, the anticorrosive agent 2-diethylaminoethanol was released into the air of a large office building. Irritative symptoms were experienced by most of the 2500 employees, and 14 workers developed asthma within 3 months of exposure. This study was undertaken to review clinical characteristics of these asthmatics. Environmental exposure monitoring data and medical records were reviewed. Seven of 14 cases were defined as "confirmed" and 7 of 14 as "suspect," using the National Institute for Occupational Safety and Health surveillance case definition of occupational asthma. Spirometry was positive in 4 of 14 of the cases and peak flow testing in 10 of 14. Three cases were diagnosed on the basis of work-related symptoms and physical examination alone. The study suggests that acute exposure to the irritating steam additive 2-diethylaminoethanol was a contributing factor in the development of clinical asthma in this population.

Adult Neuropsychological Performance Following Prenatal and Early Postnatal Exposure to Tetrachloroethylene (PCE)-contaminated Drinking Water

PubMed Central

Janulewicz, Patricia A; White, Roberta F; Martin, Brett M; Winter, Michael R; Weinberg, Janice M; Vieira, Veronica; Aschengrau, Ann

2012-01-01

This population-based retrospective cohort study examined adult performance on a battery of neuropsychological tests in relation to prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water on Cape Cod, Massachusetts. Subjects were identified through birth records from 1969 through 1983. Exposure was modeled using pipe network information from town water departments, a PCE leaching and transport algorithm, EPANet water flow modeling software, and a Geographic Information System (GIS). Results of crude and multivariate analyses among 35 exposed and 28 unexposed subjects showed no association between prenatal and early postnatal exposure and decrements on tests that assess abilities in the domains of omnibus intelligence, academic achievement or language. The results were suggestive of an association between prenatal and early postnatal PCE exposure and diminished performance on tests that assessed abilities in the domains of visuospatial functioning, learning and memory, motor, attention and mood. Because the sample size was small, most findings were not statistically significant. Future studies with larger sample sizes should be conducted to further define the neuropsychological consequences of early developmental PCE exposure. PMID:22522125

Toxicokinetic Study for Investigation of Sex Differences in Internal Dosimetry of Jet Propulsion Fuel 8 (JP-8) in the Laboratory Rat

DTIC Science & Technology

2013-07-26

8 (2000 mg/m 3 ) may have produced transient impairment of rat cochlear outer hair cell function in the absence of noise (Fechter et al., 2010); the...system is a dynamic, non- rebreathing system. In this system, an exposure atmosphere flow rate of approximately 0.5 L/min per open port was maintained...exposure atmosphere flow to the chamber or the exhaust. The outer plenum of the nose-only exposure system carried the animals’ exhaled breath and excess

Development of a prototype flexible radiator system

NASA Technical Reports Server (NTRS)

Hixon, C. W.

1979-01-01

The radiator is a roll-up flexible panel with the transport fluid manifolds located at the ends of the 27 foot length. A total of fifty Teflon flow tubes are sandwiched between the layers of silver wire mesh and sealed in the Teflon film. The transport fluid flows from an inlet manifold through 25 panel flow tubes to the end of the radiator panel into a manifold which directs the fluid into the other 25 flow tubes on its return to the base of the radiator. Deployment/retraction of the flexible radiator panel is by low pressure inflation tubes (one along each side of the panel) which incorporate a flat spring. The spring supplies the retraction force to wind the radiator panel on a drum when the pressure in the inflation tubes is relieved. Room ambient deployment tests of the radiator panel were conducted to verify the inflation tube spring deployment, and retraction capability. The panel underwent a thermal vacuum, solar spectrum exposure test. After approximately 100 hours of solar exposure, post-test inspection revealed no structural or optical properties degraded.

Changes in cochlear blood flow in mice due to loud sound exposure measured with Doppler optical microangiography and laser Doppler flowmetry.

PubMed

Reif, Roberto; Zhi, Zhongwei; Dziennis, Suzan; Nuttall, Alfred L; Wang, Ruikang K

2013-10-01

In this work we determined the contributions of loud sound exposure (LSE) on cochlear blood flow (CoBF) in an in vivo anesthetized mouse model. A broadband noise system (20 kHz bandwidth) with an intensity of 119 dB SPL, was used for a period of one hour to produce a loud sound stimulus. Two techniques were used to study the changes in blood flow, a Doppler optical microangiography (DOMAG) system; which can measure the blood flow within individual cochlear vessels, and a laser Doppler flowmetry (LDF) system; which averages the blood flow within a volume (a hemisphere of ~1.5 mm radius) of tissue. Both systems determined that the blood flow within the cochlea is reduced due to the LSE stimulation.

Enhanced cavitation and heating of flowing polymer- and lipid-shelled microbubbles and phase-shift nanodroplets during focused ultrasound exposures

NASA Astrophysics Data System (ADS)

Zhang, Siyuan; Cui, Zhiwei; Li, Chong; Zhou, Fanyu; Zong, Yujin; Wang, Supin; Wan, Mingxi

2017-03-01

Cavitation and heating are the primary mechanisms of numerous therapeutic applications of ultrasound. Various encapsulated microbubbles (MBs) and phase-shift nanodroplets (NDs) have been used to enhance local cavitation and heating, creating interests in developing ultrasound therapy using these encapsulated MBs and NDs. This work compared the efficiency of flowing polymer- and lipid-shelled MBs and phase-shift NDs in cavitation and heating during focused ultrasound (FUS) exposures. Cavitation activity and temperature were investigated when the solution of polymer- and lipid-shelled MBs and NDs flowed through the vessel in a tissue-mimicking phantom with varying flow velocities when exposed to FUS at various acoustic power levels. The inertial cavitation dose (ICD) for the encapsulated MBs and NDs were higher than those for the saline. Temperature initially increased with increasing flow velocities of the encapsulated MBs, followed by a decrease of the temperature with increasing flow velocities when the velocity was much higher. Meanwhile, ICD showed a trend of increases with increasing flow velocity. For the phase-shift NDs, ICD after the first FUS exposure was lower than those after the second FUS exposure. For the encapsulated MBs, ICD after the first FUS exposure was higher than those after the second FUS exposure. Further studies are necessary to investigate the treatment efficiency of different encapsulated MBs and phase-shift NDs in cavitation and heating.

Acute toxicity of low pH to the brown darter Etheostoma edwini under flow-through conditions

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

Kase, J.; Burnett, M.; Shortelle, A.B.

1995-12-31

The Okaloosa darter, Etheostoma okaloosae, is found exclusively in the Rocky and Boggy Bayou stream systems entering Choctawhatchee Bay, Florida. Due to its limited range and habitat degradation, E. okaloosae was added to the List of Endangered Species in 1973. The Air Force controls several active test areas situated near streams known to contain Okaloosa darters. The possible release and deposition of strong acids such as hydrochloric acid and hydrofluoric acid to stream surface water during some testing activities has raised concerns that the Okaloosa darter population may be adversely affected by episodic pH depression as a result of testingmore » activities. To evaluate the sensitivity of the Okaloosa darter to pH depression, acute toxicity tests using a closely related species, E. edwini, were conducted. Ninety-six hour and 200 min acute pH depression flow-through toxicity tests were performed with surface water collected from the Rocky Bayou stream system. The 96 h test was conducted using six concentrations held at constant pH throughout the duration of the exposure. The 200 min test used an episodic exposure; pH in the exposure chambers were initially dropped and allowed to return to normal. Mortality data obtained during the studies were used to determine the pH depression necessary to cause 50% mortality (LC50) in each scenario. The 96 h and 200 min LC50 values are, respectively, 3.79 and 2.99 s.u. The 200 min LC50 calculations are based on the lowest achieved pH in each exposure during the test. The results of these tests are part of an effort by the Air Force to make risk-based management decision regarding testing activities.« less

Compare ultrasound-mediated heating and cavitation between flowing polymer- and lipid-shelled microbubbles during focused ultrasound exposures.

PubMed

Zhang, Siyuan; Zong, Yujin; Wan, Mingxi; Yu, Xiaojun; Fu, Quanyou; Ding, Ting; Zhou, Fanyu; Wang, Supin

2012-06-01

This paper compares the efficiency of flowing polymer- and lipid-shelled microbubbles (MBs) in the heating and cavitation during focused ultrasound exposures. Temperature and cavitation activity were simultaneously measured as the two types of shelled MBs and saline flowing through a 3 mm diameter vessel in the phantom with varying flow velocities (0-20 cm/s) at different acoustic power levels (0.6-20 W) with each exposure for 5 s. Temperature and cavitation for the lipid-shelled MBs were higher than those for the polymer-shelled MBs. Temperature rise decreased with increasing flow velocities for the two types of shelled MBs and saline at acoustic power 1.5 W. At acoustic power 11.1 W, temperature rise increased with increasing flow velocities for the lipid-shelled MBs. For the polymer-shelled MBs, the temperature rise increased with increasing flow velocities from 3-15 cm/s and decreased at 20 cm/s. Cavitation increased with increasing flow velocity for the two shelled MBs and there were no significant changes of cavitation with increasing flow velocities for saline. These results suggested that lipid-shelled MBs may have a greater efficiency than polymer-shelled MBs in heating and cavitation during focused ultrasound exposures.

Secondary flow measurements and passive tracer dispersion in multi-generational models of conducting airways of the lung

NASA Astrophysics Data System (ADS)

Fresconi, Frank; Prasad, Ajay

2006-11-01

A detailed knowledge of the flow and dispersion within the human respiratory tract is desirable for numerous reasons. Both risk assessments of exposure to toxic particles in the environment and the design of medical delivery systems targeting both lung-specific conditions (asthma, cystic fibrosis, and chronic obstructive pulmonary disease (COPD)) and system-wide ailments (diabetes, cancer, hormone replacement) would profit from such an understanding. The present work features experimental efforts aimed at elucidating the fluid mechanics of the lung. Particle image velocimetry (PIV) and laser induced fluorescence (LIF) measurements of steady and oscillatory flows were undertaken in anatomically accurate models (single and multi-generational) of the conductive region of the lung. PIV results captured primary and secondary velocity fields. LIF allowed visualization of the time-dependent deformation of a passive tracer and also quantified convective dispersion through the usage of a transport profile.

Calcification in Caribbean reef-building corals at high pCO2 levels in a recirculating ocean acidification exposure system.

PubMed

Enzor, Laura A; Hankins, Cheryl; Vivian, Deborah N; Fisher, William S; Barron, Mace G

2018-02-01

Projected increases in ocean p CO 2 levels are anticipated to affect calcifying organisms more rapidly and to a greater extent than other marine organisms. The effects of ocean acidification (OA) have been documented in numerous species of corals in laboratory studies, largely tested using flow-through exposure systems. We developed a recirculating ocean acidification exposure system that allows precise p CO 2 control using a combination of off-gassing measures including aeration, water retention devices, venturi injectors, and CO 2 scrubbing. We evaluated the recirculating system performance in off-gassing effectiveness and maintenance of target p CO 2 levels over an 84-day experiment. The system was used to identify changes in calcification and tissue growth in response to elevated p CO 2 (1000 μatm) in three reef-building corals of the Caribbean: Pseudodiploria clivosa , Montastraea cavernosa , and Orbicella faveolata . All three species displayed an overall increase in net calcification over the 84-day exposure period regardless of p CO 2 level (control +0.28- 1.12 g, elevated p CO 2 +0.18- 1.16 g), and the system was effective at both off-gassing acidified water to ambient p CO 2 levels, and maintaining target elevated p CO 2 levels over the 3-month experiment.

Eruption and emplacement dynamics of a thick trachytic lava flow of the Sancy volcano (France)

NASA Astrophysics Data System (ADS)

Latutrie, Benjamin; Harris, Andrew; Médard, Etienne; Gurioli, Lucia

2017-01-01

A 70-m-thick, 2200-m-long (51 × 106 m3) trachytic lava flow unit underlies the Puy de Cliergue (Mt. Dore, France). Excellent exposure along a 400-m-long and 60- to 85-m-high section allows the flow interior to be accessed on two sides of a glacial valley that cuts through the unit. We completed an integrated morphological, structural, textural, and chemical analysis of the unit to gain insights into eruption and flow processes during emplacement of this thick silicic lava flow, so as to elucidate the chamber and flow dynamic processed that operate during the emplacement of such systems. The unit is characterized by an inverse chemical stratification, where there is primitive lava beneath the evolved lava. The interior is plug dominated with a thin basal shear zone overlying a thick basal breccia, with ramping affecting the entire flow thickness. To understand these characteristics, we propose an eruption model that first involves processes operating in the magma chamber whereby a primitive melt is injected into an evolved magma to create a mixed zone at the chamber base. The eruption triggered by this event first emplaced a trachytic dome, into which banded lava from the chamber base was injected. Subsequent endogenous dome growth led to flow down the shallow slope to the east on which the highly viscous (1012 Pa s) coulée was emplaced. The flow likely moved extremely slowly, being emplaced over a period of 4-10 years in a glacial manner, where a thick (>60-m) plug slid over a thin (5-m-thick) basal shear zone. Excellent exposure means that the Puy de Cliergue complex can be viewed as a case type location for understanding and defining the eruption and emplacement of thick, high-viscosity, silicic lava flow systems.

Structural Analysis of Silicic Lavas Reveals the Importance of Endogenous Flow During Emplacement

NASA Astrophysics Data System (ADS)

Andrews, G. D.; Martens, A.; Isom, S.; Maxwell, A.; Brown, S. R.

2017-12-01

Recent observations of silicic lava flows in Chile strongly suggest sustained, endogeneous flow beneath an insulating carapace, where the flow advances through breakouts at the flow margin. New mapping of vertical exposures around the margin of Obsidian Dome, California, has identified discreet lobe structures in cross-section, suggesting that flow-front breakouts occured there during emplacement. The flow lobes are identified through structural measurements of flow-banding orientation and the stretching directions of vesicles. Newly acquired lidar of the Inyo Domes, including Obsidian Dome, is being analyzed to better understand the patterns of folding on the upper surface of the lavas, and to test for fold vergence patterns that may distinguish between endogenous and exogenous flow.

Small fish models for identifying carcinogens in the aqueous environment

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

Hawkins, W.E.; Overstreet, R.M.; Walker, W.W.

1988-10-01

Contaminants in water and sediments can be carcinogenic to aquatic wildlife as well as humans. Identifying those carcinogens, however, is difficult because they often occur in low concentrations and exert their effects over a large part of the life span of affected organisms. Furthermore, the carcinogens are often components of complex mixtures. Recent studies suggest that laboratory-reared fish species might be well suited for testing water-associated and other carcinogens. Here, we review the principal carcinogen exposure methods that utilize small fish species or can be adapted to utilize small fish species to detect carcinogens in aqueous environments. Emphasis is placedmore » on methods for which the end-point is tumor induction. The methods discussed are dietary exposures, skin painting, embryo microinjection, early life stage (pulse) exposures, static water exposures, flow-through exposures, and controlled field exposures. Early life stage exposures seem to have the greatest utility with regard to carcinogen sensitivity, ease of administration, disposal of test compounds, and economy of materials and effort. For certain types of carcinogens, however, long-term flow-through exposures are probably required. In summary, small fish carcinogenesis models offer an array of methodologies that can be utilized in a variety of combinations depending on compounds tested, exposure parameters employed, and end point sought.« less

Exposure Through Runoff and Ground Water Contamination Differentially Impact Behavior and Physiology of Crustaceans in Fluvial Systems.

PubMed

Steele, Alexandra N; Belanger, Rachelle M; Moore, Paul A

2018-06-19

Chemical pollutants enter aquatic systems through numerous pathways (e.g., surface runoff and ground water contamination), thus associating these contaminant sources with varying hydrodynamic environments. The hydrodynamic environment shapes the temporal and spatial distribution of chemical contaminants through turbulent mixing. The differential dispersal of contaminants is not commonly addressed in ecotoxicological studies and may have varying implications for organism health. The purpose of this study is to understand how differing routes of exposure to atrazine alter social behaviors and physiological responses of aquatic organisms. This study used agonistic encounters in crayfish Orconectes virilis as a behavioral assay to investigate impact of sublethal concentrations of atrazine (0, 40, 80, and 160 µg/L) delivered by methods mimicking ground water and surface runoff influx into flow-through exposure arenas for a total of 23 h. Each experimental animal participated in a dyadic fight trial with an unexposed opponent. Fight duration and intensity were analyzed. Experimental crayfish hepatopancreas and abdominal muscle tissue samples were analyzed for cytochrome P450 and acetylcholinesterase levels to discern mechanism of detoxification and mode of action of atrazine. Atrazine delivered via runoff decreased crayfish overall fight intensity and contrastingly ground water delivery increased overall fight intensity. The behavioral differences were mirrored by increases in cytochrome P450 activity, whereas no differences were found in acetylcholinesterase activity. This study demonstrates that method of delivery into fluvial systems has differential effects on both behavior and physiology of organisms and emphasizes the need for the consideration of delivery pathway in ecotoxicological studies and water-impairment standards.

Dual exposure interferometry. [gas dynamics and flow visualization

NASA Technical Reports Server (NTRS)

Smeets, G.; George, A.

1982-01-01

The application of dual exposure differential interferometry to gas dynamics and flow visualization is discussed. A differential interferometer with Wallaston prisms can produce two complementary interference fringe systems, depending on the polarization of the incident light. If these two systems are superimposed on a film, with one exposure during a phenomenon, the other before or after, the phenomenon will appear on a uniform background. By regulating the interferometer to infinite fringe distance, a resolution limit of approximately lambda/500 can be obtained in the quantitative analysis of weak phase objects. This method was successfully applied to gas dynamic investigations.

Multi-exposure speckle imaging of cerebral blood flow: a pilot clinical study (Conference Presentation)

NASA Astrophysics Data System (ADS)

Richards, Lisa M.; Kazmi, S. M. S.; Olin, Katherine E.; Waldron, James S.; Fox, Douglas J.; Dunn, Andrew K.

2017-03-01

Monitoring cerebral blood flow (CBF) during neurosurgery is essential for detecting ischemia in a timely manner for a wide range of procedures. Multiple clinical studies have demonstrated that laser speckle contrast imaging (LSCI) has high potential to be a valuable, label-free CBF monitoring technique during neurosurgery. LSCI is an optical imaging method that provides blood flow maps with high spatiotemporal resolution requiring only a coherent light source, a lens system, and a camera. However, the quantitative accuracy and sensitivity of LSCI is limited and highly dependent on the exposure time. An extension to LSCI called multi-exposure speckle imaging (MESI) overcomes these limitations, and was evaluated intraoperatively in patients undergoing brain tumor resection. This clinical study (n = 7) recorded multiple exposure times from the same cortical tissue area, and demonstrates that shorter exposure times (≤1 ms) provide the highest dynamic range and sensitivity for sampling flow rates in human neurovasculature. This study also combined exposure times using the MESI model, demonstrating high correlation with proper image calibration and acquisition. The physiological accuracy of speckle-estimated flow was validated using conservation of flow analysis on vascular bifurcations. Flow estimates were highly conserved in MESI and 1 ms exposure LSCI, with percent errors at 6.4% ± 5.3% and 7.2% ± 7.2%, respectively, while 5 ms exposure LSCI had higher errors at 21% ± 10% (n = 14 bifurcations). Results from this study demonstrate the importance of exposure time selection for LSCI, and that intraoperative MESI can be performed with high quantitative accuracy.

Occupational exposure to nitrous oxide - the role of scavenging and ventilation systems in reducing the exposure level in operating rooms.

PubMed

Krajewski, Wojciech; Kucharska, Malgorzata; Wesolowski, Wiktor; Stetkiewicz, Jan; Wronska-Nofer, Teresa

2007-03-01

The aim of this study was to assess the level of occupational exposure to nitrous oxide (N(2)O) in operating rooms (ORs), as related to different ventilation and scavenging systems used to remove waste anaesthetic gases from the work environment. The monitoring of N(2)O in the air covered 35 ORs in 10 hospitals equipped with different systems for ventilation and anaesthetic scavenging. The examined systems included: natural ventilation with supplementary fresh air provided by a pressure ventilation system (up to 6 air changes/h); pressure and exhaust ventilation systems equipped with ventilation units supplying fresh air to and discharging contaminated air outside the working area (more than 10 air changes/h); complete air-conditioning system with laminar air flow (more than 15 air changes/h). The measurements were carried out during surgical procedures (general anaesthesia induced intravenously and maintained with inhaled N(2)O and sevofluran delivered through cuffed endotracheal tubes) with connected or disconnected air scavenging. Air was collected from the breathing zone of operating personnel continuously through the whole time of anaesthesia to Tedlar((R)) bags, and N(2)O concentrations in air samples were analyzed by adsorption gas chromatography/mass spectrometry. N(2)O levels in excess of the occupational exposure limit (OEL) value of 180mg/m(3) were registered in all ORs equipped with ventilation systems alone. The OEL value was exceeded several times in rooms with natural ventilation plus supplementary pressure ventilations and twice or less in those with pressure/exhaust ventilation systems or air conditioning. N(2)O levels below or within the OEL value were observed in rooms where the system of air conditioning or pressure/exhaust ventilation was combined with scavenging systems. Systems combining natural/pressure ventilation with scavenging were inadequate to maintain N(2)O concentration below the OEL value. Air conditioning and an efficient pressure/exhaust ventilation (above 12 air exchanges/h) together with efficient active scavenging systems are sufficient to sustain N(2)O exposure in ORs at levels below or within the OEL value of 180mg/m(3).

Intrathecal Pump Exposure to Electromagnetic Interference: A Report of Device Interrogation following Multiple ECT Sessions.

PubMed

Bicket, Mark C; Hanna, George M

2016-02-01

Intrathecal drug delivery systems represent an increasingly common treatment modality for patients with a variety of conditions, including chronic pain and spasticity. Pumps rely on electronic programming to properly control and administer highly concentrated medications. Electromagnetic interference (EMI) is a known exposure that may cause a potential patient safety issue stemming from direct patient injury, pump damage, or changes to pump operation or flow rate. The objective of our case report was to describe an approach to evaluating a patient with a pump prior to and following exposure to EMI from electroconvulsive therapy (ECT), as well as to document findings from device interrogations associated with this event. Case report. Academic university-based pain management center. We present the case of a patient with an intrathecal pump who underwent multiple exposures to EMI in the form of 42 ECT sessions. Interrogation of the intrathecal drug delivery system revealed no safety issues following ECT sessions. At no time were error messages, unintentional changes in event logs, unintentional changes in pump settings, or evidence of pump stall or over-infusion noted. Communication with multiple entities (patient, family, consulting physicians, and device manufacturer) and maintaining vigilance through device interrogation both before and after EMI exposure are appropriate safeguards to mitigate the risk and detect potential adverse events of EMI with intrathecal drug delivery systems. Given the infrequent reports of device exposure to ECT, best practices may be derived from experience with EMI exposure from magnetic resonance imaging (MRI). Although routine EMI exposure to intrathecal drug delivery systems should be avoided, we describe one patient with repeated exposure to ECT without apparent complication.

Modeling population exposures to silver nanoparticles present in consumer products

NASA Astrophysics Data System (ADS)

Royce, Steven G.; Mukherjee, Dwaipayan; Cai, Ting; Xu, Shu S.; Alexander, Jocelyn A.; Mi, Zhongyuan; Calderon, Leonardo; Mainelis, Gediminas; Lee, KiBum; Lioy, Paul J.; Tetley, Teresa D.; Chung, Kian Fan; Zhang, Junfeng; Georgopoulos, Panos G.

2014-11-01

Exposures of the general population to manufactured nanoparticles (MNPs) are expected to keep rising due to increasing use of MNPs in common consumer products (PEN 2014). The present study focuses on characterizing ambient and indoor population exposures to silver MNPs (nAg). For situations where detailed, case-specific exposure-related data are not available, as in the present study, a novel tiered modeling system, Prioritization/Ranking of Toxic Exposures with GIS (geographic information system) Extension (PRoTEGE), has been developed: it employs a product life cycle analysis (LCA) approach coupled with basic human life stage analysis (LSA) to characterize potential exposures to chemicals of current and emerging concern. The PRoTEGE system has been implemented for ambient and indoor environments, utilizing available MNP production, usage, and properties databases, along with laboratory measurements of potential personal exposures from consumer spray products containing nAg. Modeling of environmental and microenvironmental levels of MNPs employs probabilistic material flow analysis combined with product LCA to account for releases during manufacturing, transport, usage, disposal, etc. Human exposure and dose characterization further employ screening microenvironmental modeling and intake fraction methods combined with LSA for potentially exposed populations, to assess differences associated with gender, age, and demographics. Population distributions of intakes, estimated using the PRoTEGE framework, are consistent with published individual-based intake estimates, demonstrating that PRoTEGE is capable of capturing realistic exposure scenarios for the US population. Distributions of intakes are also used to calculate biologically relevant population distributions of uptakes and target tissue doses through human airway dosimetry modeling that takes into account product MNP size distributions and age-relevant physiological parameters.

Cavitation enhances coagulated size during pulsed high-intensity focussed ultrasound ablation in an isolated liver perfusion system.

PubMed

Zhao, Lu-Yan; Liu, Shan; Chen, Zong-Gui; Zou, Jian-Zhong; Wu, Feng

2016-11-24

To investigate whether cavitation enhances the degree of coagulation during pulsed high-intensity focussed ultrasound (HIFU) in an isolated liver perfusion system. Isolated liver was treated by pulsed HIFU or continuous-wave HIFU with different portal vein flow rates. The cavitation emission during exposure was recorded, and real-time ultrasound images were used to observe changes in the grey scale. The coagulation size was measured and calculated. HIFU treatment led to complete coagulation necrosis and total cell destruction in the target regions. Compared to exposure at a duty cycle (DC) of 100%, the mean volumes of lesions induced by 6 s exposure at DCs of 50% and 10% were significantly larger (P < .01) but were smaller at a DC of 5%. The necrosis volume was negatively related to the perfusion rate in the pulsed HIFU at a DC of 50% for exposure durations of 4 and 6 s, while the perfusion flow rate did not affect the necrosis volume for exposure durations of 1, 2 and 3 s. For increased perfusion flow rates, there was no significant decrease in the cavitation activity for the pulsed-HIFU (P > .05). For continuous-wave HIFU exposure, there was a significant decrease in the necrosis volume and cavitation activity for exposure times of 1, 2, 3, 4, and 6 s with increasing portal perfusion rates. Perfusion flow rates negatively influence cavitation activity and coagulation volume. Ablation is significantly enhanced during pulsed HIFU exposure compared with continuous-wave HIFU.

Influence of Current Velocity on Uranium Adsorption from Seawater Using an Amidoxime-based Polymer Fiber Adsorbent

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

Ladshaw, Austin; Kuo, Li-Jung; Strivens, Jonathan

2017-02-08

Passive adsorption using amidoxime-based polymeric adsorbents is being developed for uranium recovery from seawater. The local oceanic current velocity where the adsorbent is deployed is a key variable in determining locations that will maximize uranium adsorption rates. Two independent experimental approaches using flow-through columns and recirculating flumes were used to assess the influence of linear velocity on uranium uptake kinetics by the adsorbent. Little to no difference was observed in the uranium adsorption rate vs. linear velocity for seawater exposure in flow-through columns. In contrast, adsorption results from seawater exposure in a recirculating flume showed a nearly linear trend withmore » current velocity. The difference in adsorbent performance between columns and flume can be attributed to (i) flow resistance provided by the adsorbent braid in the flume and (ii) enhancement in braid movement (fluttering) with increasing linear velocity.« less

Influence of Current Velocity on Uranium Adsorption from Seawater Using an Amidoxime-Based Polymer Fiber Adsorbent

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

Ladshaw, Austin; Kuo, Li-Jung; Strivens, Jonathan

2017-02-17

Passive adsorption using amidoxime-based polymeric adsorbents is being developed for uranium recovery from seawater. The local oceanic current velocity where the adsorbent is deployed is a key variable in determining locations that will maximize uranium adsorption rates. Two independent experimental approaches using flow-through columns and recirculating flumes were used to assess the influence of linear velocity on uranium uptake kinetics by the adsorbent. Little to no difference was observed in the uranium adsorption rate vs. linear velocity for seawater exposure in flow-through columns. In contrast, adsorption results from seawater exposure in a recirculating flume showed a nearly linear trend withmore » current velocity. The difference in adsorbent performance between columns and flume can be attributed to (i) flow resistance provided by the adsorbent braid in the flume and (ii) enhancement in braid movement (fluttering) with increasing linear velocity.« less

Flow Visualization Studies in the Novacor Left Ventricular Assist System CRADA PC91-002, Final Report

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

Borovetz, H.S.; Shaffer, F.; Schaub, R.

This paper discusses a series of experiments to visualize and measure flow fields in the Novacor left ventricular assist system (LVAS). The experiments utilize a multiple exposure, optical imaging technique called fluorescent image tracking velocimetry (FITV) to hack the motion of small, neutrally-buoyant particles in a flowing fluid.

Emesis, radiation exposure, and local cerebral blood flow in the ferret

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

Tuor, U.I.; Kondysar, M.H.; Harding, R.K.

1988-06-01

We examined the sensitivity of the ferret to emetic stimuli and the effect of radiation exposure near the time of emesis on local cerebral blood flow. Ferrets vomited following the administration of either apomorphine (approx 45% of the ferrets tested) or peptide YY (approx 36% of those tested). Exposure to radiation was a very potent emetic stimulus, but vomiting could be prevented by restraint of the hindquarters of the ferret. Local cerebral blood flow was measured using a quantitative autoradiographic technique and with the exception of several regions in the telencephalon and cerebellum, local cerebral blood flow in the ferretmore » was similar to that in the rat. In animals with whole-body exposure to moderate levels of radiation (4 Gy of /sup 137/Cs), mean arterial blood pressure was similar to that in the control group. However, 15-25 min following irradiation there was a general reduction of local cerebral blood flow ranging from 7 to 33% of that in control animals. These cerebral blood flow changes likely correspond to a reduced activation of the central nervous system.« less

Influence of magnetic field on chemically reactive blood flow through stenosed bifurcated arteries

NASA Astrophysics Data System (ADS)

Hossain, Khan Enaet; Haque, Md. Mohidul

2017-06-01

Dynamic response of mass transfer in chemically reactive blood flow through bifurcated arteries under the stenotic condition is numerically studied in the present of a uniform magnetic field. The blood flowing through the artery is assumed an incompressible, fully developed and Newtonian. The nonlinear unsteady flow phenomena are governed by the Navier-Stokes and concentration equations. All these equations together with the appropriate boundary conditions describing the present biomechanical problem are transformed by using a radial transformation and the numerical results are obtained using a finite difference technique. Effects of stenosed bifurcation and externally applied magnetic field on the blood flow with chemical reaction are discussed with the help of graph. All the flow characteristics are found to be affected by the presence of chemical reaction and exposure of magnetic field of different intensities. Finally some important findings of the problem are concluded in this work.

Survival and growth of newly transformed Lampsilis cardium and Lampsilis siliquoidea in a flow-through, continuous feeding test system

USGS Publications Warehouse

Meinertz, Jeffery R.; Schreier, Theresa M.; Hess, Karina R.; Bartsch, Michelle

2011-01-01

A test system was evaluated for assessing chronic toxicity of waterborne chemicals with early life stage mussels. To determine if the test system could result in ≥80% survival in a control (unexposed) group, fat mucket mussels (Lampsilis siliquoidea Barnes, 1823) and plain pocketbook mussels (L. cardium Rafinesque, 1820) 1 day post transformation were stocked into test chambers (250 mL beakers, water volume, 200 mL, 21 °C, 40 mussels of 1 species per chamber) within a test system constructed for conducting chronic, continuous exposure, flow-through toxicity tests. The test system contained 60 chambers containing silica sand, 30 chambers with L. siliquoidea, and 30 with L. cardium. Each chamber in the continuous feeding system received 1 of 6 food types prepared with concentrated algal products. After 28 days, mussels were harvested from chambers to assess survival and growth. For L. siliquoidea, mean survival ranged from 34 to 80% and mean shell length ranged from 464 to 643 µm. For L. cardium, mean survival ranged from 12 to 66% and mean shell length ranged from 437 to 612 µm. The maximum mean growth rate for L. siliquoidea was 12.7 µm/d and for L. cardium was 11.8 µm/d. When offered a continuous diet of Nannochloropsis, Tetraselmis, and Chlorella for 28 days in the test system, the survival of 1 day post transformation L. siliquoidea was 80%. The test system can be easily enhanced with a pumping system continuously delivering test chemical to the test system's flow stream allowing for chronic toxicity tests with 1 day post transformation mussels.

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

Macauley, J.M.; Clark, J.R.; Pitts, A.R.

Concurrent 12-week laboratory and field studies were conducted to determine toxicity of the suspended particulate phase (SPP) of drilling fluid to Thalassia testudinum and its epiphytes. Test systems were treated once per week to achieve nominal concentrations of 100 mg/L SPP. Chlorophyll content of Thalassia leaves and epiphyte biomass and chlorophyll content were monitored during each test. Laboratory exposures were conducted in 7-L, flow-through (7 L/h) microcosms consisting of Plexiglas cylinders containing intact cores of Thalassia from a local seagrass bed. Field exposures were conducted in water-tight plexiglas chambers (2 m x 2 m x 1.5 m) placed over testmore » plots in a seagrass bed for 24 h during SPP additions. Epiphyte biomass was reduced after 6 weeks of intermittent exposure to SPP in laboratory and field tests. After 12 weeks, epiphyte biomass had increased to densities similar to control values.« less

A Gas Chromatographic System for the Detection of Ethylene Gas Using Ambient Air as a Carrier Gas.

PubMed

Zaidi, Nayyer Abbas; Tahir, Muhammad Waseem; Vellekoop, Michael J; Lang, Walter

2017-10-07

Ethylene gas is a naturally occurring gas that has an influence on the shelf life of fruit during their transportation in cargo ships. An unintentional exposure of ethylene gas during transportation results in a loss of fruit. A gas chromatographic system is presented here for the detection of ethylene gas. The gas chromatographic system was assembled using a preconcentrator, a printed 3D printed gas chromatographic column, a humidity sensor, solenoid valves, and an electrochemical ethylene gas sensor. Ambient air was used as a carrier gas in the gas chromatographic system. The flow rate was fixed to 10 sccm. It was generated through a mini-pump connected in series with a mass flow controller. The metal oxide gas sensor is discussed with its limitation in ambient air. The results show the chromatogram obtained from metal oxide gas sensor has low stability, drifts, and has uncertain peaks, while the chromatogram from the electrochemical sensor is stable and precise. Furthermore, ethylene gas measurements at higher ppb concentration and at lower ppb concentration were demonstrated with the electrochemical ethylene gas sensor. The system separates ethylene gas and humidity. The chromatograms obtained from the system are stable, and the results are 1.2% repeatable in five similar measurements. The statistical calculation of the gas chromatographic system shows that a concentration of 2.3 ppb of ethylene gas can be detected through this system.

Advances in Dynamic Transport of Organic Contaminants in Karst Groundwater Systems

NASA Astrophysics Data System (ADS)

Padilla, I. Y.; Vesper, D.; Alshawabkeh, A.; Hellweger, F.

2011-12-01

Karst groundwater systems develop in soluble rocks such as limestone, and are characterized by high permeability and well-developed conduit porosity. These systems provide important freshwater resources for human consumption and ecological integrity of streams, wetlands, and coastal zones. The same characteristics that make karst aquifers highly productive make them highly vulnerable to contamination. As a result, karst aquifers serve as an important route for contaminants exposure to humans and wildlife. Transport of organic contaminants in karst ground-water occurs in complex pathways influenced by the flow mechanism predominating in the aquifer: conduit-flow dominated systems tend to convey solutes rapidly through the system to a discharge point without much attenuation; diffuse-flow systems, on the other hand, can cause significant solute retardation and slow movement. These two mechanisms represent end members of a wide spectrum of conditions found in karst areas, and often a combination of conduit- and diffuse-flow mechanisms is encountered, where both flow mechanisms can control the fate and transport of contaminants. This is the case in the carbonate aquifers of northern Puerto Rico. This work addresses advances made on the characterization of fate and transport processes in karst ground-water systems characterized by variable conduit and/or diffusion dominated flow under high- and low-flow conditions. It involves laboratory-scale physical modeling and field-scale sampling and historical analysis of contaminant distribution. Statistical analysis of solute transport in Geo-Hydrobed physical models shows the heterogeneous character of transport dynamics in karstic units, and its variability under different flow regimes. Field-work analysis of chlorinated volatile organic compounds and phthalates indicates a large capacity of the karst systems to store and transmit contaminants. This work is part of the program "Puerto Rico Testsite for Exploring Contamination Threats (PRoTECT)" supported by the National Institute of Environmental Health Sciences (NIEHS, Grant Award No. P42ES017198).

Evaluation of Jet Fuel Induced Hearing Loss in Rats

DTIC Science & Technology

2011-10-13

flow of approximately 20 liters per minute (lpm) through the nebulizer. This air flow coupled with the nebulizer nozzle design created an...inch PVC pipe contained the spray pattern. The pipe was initially reduced in size to accept an orifice plate which can be used to measure flow rate...chamber flow . Two drain ports were used to remove residual jet fuel which accumulated after a day‟s exposure. To achieve the 10 1500 mg/m 3

Effect of ventilation velocity on hexavalent chromium and isocyanate exposures in aircraft paint spraying.

PubMed

Bennett, James; Marlow, David; Nourian, Fariba; Breay, James; Feng, Amy; Methner, Mark

2018-03-01

Exposure control system performance was evaluated during aircraft paint spraying at a military facility. Computational fluid dynamics (CFD) modeling, tracer gas testing, and exposure monitoring examined contaminant exposure vs. crossflow ventilation velocity. CFD modeling using the RNG k-ϵ turbulence model showed exposures to simulated methyl isobutyl ketone of 294 and 83.6 ppm, as a spatial average of five worker locations, for velocities of 0.508 and 0.381 m/s (100 and 75 fpm), respectively. In tracer gas experiments, observed supply/exhaust velocities of 0.706/0.503 m/s (136/99 fpm) were termed full-flow, and reduced velocities were termed 3/4-flow and half-flow. Half-flow showed higher tracer gas concentrations than 3/4-flow, which had the lowest time-averaged concentration, with difference in log means significant at the 95% confidence level. Half-flow compared to full-flow and 3/4-flow compared to full-flow showed no statistically significant difference. CFD modeling using these ventilation conditions agreed closely with the tracer results for the full-flow and 3/4-flow comparison, yet not for the 3/4-flow and half-flow comparison. Full-flow conditions at the painting facility produced a velocity of 0.528 m/s (104 fpm) midway between supply and exhaust locations, with the supply rate of 94.4 m 3 /s (200,000 cfm) exceeding the exhaust rate of 68.7 m 3 /s (146,000 cfm). Ventilation modifications to correct this imbalance created a midhangar velocity of 0.406 m/s (80.0 fpm). Personal exposure monitoring for two worker groups-sprayers and sprayer helpers ("hosemen")-compared process duration means for the two velocities. Hexavalent chromium (Cr[VI]) exposures were 500 vs. 360 µg/m 3 for sprayers and 120 vs. 170 µg/m 3 for hosemen, for 0.528 m/s (104 fpm) and 0.406 m/s (80.0 fpm), respectively. Hexamethylene diisocyanate (HDI) monomer means were 32.2 vs. 13.3 µg/m 3 for sprayers and 3.99 vs. 8.42 µg/m 3 for hosemen. Crossflow velocities affected exposures inconsistently, and local work zone velocities were much lower. Aircraft painting contaminant control is accomplished better with the unidirectional crossflow ventilation presented here than with other observed configurations. Exposure limit exceedances for this ideal condition reinforce continued use of personal protective equipment.

Reproducible direct exposure environmental testing of metal-based magnetic media

NASA Technical Reports Server (NTRS)

Sides, Paul J.

1994-01-01

A flow geometry and flow rate for mixed flowing gas testing is proposed. Use of an impinging jet of humid polluted air can provide a uniform and reproducible exposure of coupons of metal-based magnetic media. Numerical analysis of the fluid flow and mass transfer in such as system has shown that samples confined within a distance equal to the nozzle radius on the surface of impingement are uniformly accessible to pollutants in the impinging gas phase. The critical factor is the nozzle height above the surface of impingement. In particular, the uniformity of exposure is less than plus/minus 2% for a volumetric flow rate of 1600 cm(exp 3)/minute total flow with the following specifications: For a one inch nozzle, the height of the nozzle opening above the stage should be 0.177 inches; for a 2 inch nozzle - 0.390 inches. Not only is the distribution uniform, but one can calculate the maximum delivery rate of pollutants to the samples for comparison with the observed deterioration.

The influence of resource strategies on childhood phthalate exposure--the role of REACH in a zero waste society.

PubMed

Lee, Jihyun; Pedersen, Anders Branth; Thomsen, Marianne

2014-12-01

The present study aims to investigate how resource strategies, which intend to reduce waste and increase recycling, influence on human exposure to hazardous chemicals from material recycling. In order to examine the flows of hazardous chemicals in recycled material, a mass flow analysis of plastics and paper at European level, including the flow of phthalates, i.e. di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP), and benzyl-butyl phthalate (BBP), has been performed. The result for the year 2012 shows that 26% of plastic wastes and 60% of paper consumed in Europe were recycled. This corresponds to the finding that approximately 4% of DEHP and BBP and 18% of DBP annual demands in Europe as raw material re-enter the product cycle with recycled plastics and paper. To examine the potential contribution of the phthalate exposure through recycled plastics and paper, a case study assessing the childhood exposures to phthalates from foods packed in recycled paper and plastics has been performed for 2-year-old children in Denmark. The result verifies that an increase in recycled paperboard and PET bottles in food packaging material causes a significant increase in childhood exposure to DBP corresponding to an additional exposure of 0.116-0.355 μg/kg bw/day; up to 18% of the total DBP exposure in Danish 2-year-olds. While most of the DEHP exposure can be explained, more than 50% of DBP and 70% of BBP exposure sources still remain to be identified. Finally, a conceptual framework for a circular economy based on sustainable and clean resource flows is proposed in order to increase material recycling without increasing adverse health effects. Copyright © 2014 Elsevier Ltd. All rights reserved.

Antarctic meteorites

NASA Astrophysics Data System (ADS)

Cassidy, W. A.; Rancitelli, L. A.

1982-04-01

An abundance of meteorites has been discovered on two sites in the Antarctic which may assist in the study of the origins of meteorites and the history of the solar system. Characteristics particular to those meteorites discovered in this region are explained. These specimens, being well preserved due to the climate, have implications in the study of the cosmic ray flux through time, the meteoroid complex in space, and cosmic ray exposure ages. Implications for the study of the Antarctic, particularly the ice flow, are also discussed. Further discoveries of meteorites in this region are anticipated.

Nose-only exposure system

DOEpatents

Cannon, William C.; Bass, Edward W.; Decker, Jr., John R.

1988-01-01

An exposure system for supplying a gaseous material, i.e. an aerosol, gas or a vapor, directly to the noses of experimental animals includes concentric vertical inner and outer manifolds. The outer manifold connects with the necks of a large number of bottles in which the animals are confined with their noses adjacent the bottle necks. Readily detachable small tubes communicate with the inner manifold and extend to the necks of the bottles. The upper end of the outer manifold and the lower end of the inner manifold are closed. Gaseous material is supplied to the upper end of the inner manifold, flows through the small tubes to points adjacent the noses of the individual animals, then is drawn out through the bottom of the outer manifold. The bottles are readily removable and the device can be disassembled, e.g., for cleaning, by removing the bottles, removing the small tubes, and lifting the inner manifold from the outer manifold. The bottles are supported by engagement of their necks with the outer manifold supplemented, if additional support is required, by individual wire cradles. The outer ends of the bottles are closed by plugs, through which pass metal tubes which receive the tails of the animals (usually rodents) and which serve to dissipate body heat. The entire device is mounted for rotation on turntable bearings.

Thoron Mitigation System based on charcoal bed for applications in thorium fuel cycle facilities (part 2): Development, characterization, and performance evaluation.

PubMed

Sudeep Kumara, K; Sahoo, B K; Gaware, J J; Sapra, B K; Mayya, Y S; Karunakara, N

2017-06-01

Exposure due to thoron ( 220 Rn) gas and its decay products in a thorium fuel cycle facility handling thorium or 232 U/ 233 U mixture compounds is an important issue of radiological concern requiring control and mitigation. Adsorption in a flow-through charcoal bed offers an excellent method of alleviating the release of 220 Rn into occupational and public domain. In this paper, we present the design, development, and characterization of a Thoron Mitigation System (TMS) for industrial application. Systematic experiments were conducted in the TMS for examining the 220 Rn mitigation characteristics with respect to a host of parameters such as flow rate, pressure drop, charcoal grain size, charcoal mass and bed depth, water content, and heat of the carrier gas. An analysis of the experimental data shows that 220 Rn attenuation in a flow through charcoal bed is not exponential with respect to the residence time, L/U a (L: bed depth; U a : superficial velocity), but follows a power law behaviour, which can be attributed to the occurrence of large voids due to wall channeling in a flow through bed. The study demonstrates the regeneration of charcoal adsorption capacity degraded due to moisture adsorption, by hot air blowing technique. It is found that the mitigation factor (MF), which is the ratio of the inlet 220 Rn concentration (C in ) to the outlet 220 Rn concentration (C out ), of more than 10 4 for the TMS is easily achievable during continuous operation (>1000 h) at a flow rate of 40 L min -1 with negligible (<1 cm of water column) pressure drop. The Thoron Mitigation System based on adsorption on charcoal bed offers a compact and effective device to remove 220 Rn from affluent air streams in a space constrained domain. The prototype system has been installed in a thorium fuel cycle facility where it is being evaluated for its long-term performance and overall effectiveness in mitigating 220 Rn levels in the workplace. Copyright © 2017 Elsevier Ltd. All rights reserved.

Methods to improve traffic flow and noise exposure estimation on minor roads.

PubMed

Morley, David W; Gulliver, John

2016-09-01

Address-level estimates of exposure to road traffic noise for epidemiological studies are dependent on obtaining data on annual average daily traffic (AADT) flows that is both accurate and with good geographical coverage. National agencies often have reliable traffic count data for major roads, but for residential areas served by minor roads, especially at national scale, such information is often not available or incomplete. Here we present a method to predict AADT at the national scale for minor roads, using a routing algorithm within a geographical information system (GIS) to rank roads by importance based on simulated journeys through the road network. From a training set of known minor road AADT, routing importance is used to predict AADT on all UK minor roads in a regression model along with the road class, urban or rural location and AADT on the nearest major road. Validation with both independent traffic counts and noise measurements show that this method gives a considerable improvement in noise prediction capability when compared to models that do not give adequate consideration to minor road variability (Spearman's rho. increases from 0.46 to 0.72). This has significance for epidemiological cohort studies attempting to link noise exposure to adverse health outcomes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Non-Flow-Through Fuel Cell System Test Results and Demonstration on the SCARAB Rover

NASA Technical Reports Server (NTRS)

Scheidegger, Brianne; Burke, Kenneth; Jakupca, Ian

2012-01-01

This presentation describes the results of the demonstration of a non-flow-through PEM fuel cell as part of a power system on the SCARAB rover at the NASA Glenn Research Center. A 16-cell non-flow-through fuel cell stack from Infinity Fuel Cell and Hydrogen, Inc. was incorporated into a power system designed to act as a range extender by providing power to the SCARAB rover s hotel loads. The power system, including the non-flow-through fuel cell technology, successfully demonstrated its goal as a range extender by powering hotel loads on the SCARAB rover, making this demonstration the first to use the non-flow-through fuel cell technology on a mobile platform.

Bioaccumulation of polycyclic aromatic compounds: 1. Bioconcentration in two marine species and in semipermeable membrane devices during chronic exposure to dispersed crude oil.

PubMed

Baussant, T; Sanni, S; Jonsson, G; Skadsheim, A; Børseth, J F

2001-06-01

Assessing the fate in marine biota of hydrocarbons derived from oil particles that are discharged during exploration and production is of relevant environmental concern. However, a rather complex experimental setup is required to carry out such investigations. In this study, a sophisticated tool, the continuous-flow system (CFS), was used to mimic dispersed oil exposure to marine biota. Polycyclic aromatic hydrocarbon (PAH) uptake was studied in two species, the blue mussel Mytilus edulis and juvenile of the turbot Scophthalmus maximus, and in semipermeable membrane devices (SPMD) exposed to crude oil dispersed in a flow-through system. After an exposure period of 8 to 21 d, elimination in organisms and devices was analyzed for 9 to 10 d following transfer to PAH-free seawater. Principal component analysis (PCA) revealed different PAH patterns. In mussel and SPMD, the PAH profiles were very close to that analyzed in seawater. Slight differences were, however, indicated for large molecules with log Kow above six. Nonachievement of steady-state concentration and bioavailability of PAH in oil droplets may account for these differences. The PAH composition in fish revealed only congeners with two to three aromatic rings. A combination of bioavailability and efficient metabolism of the larger PAH molecules may explain this pattern. The CFS made possible a better understanding of some critical factors governing bioconcentration in marine biota from dispersed oil. Yet the results illustrate that uptake of PAH from exposure to oil particles is complex and that different species may bioconcentrate different molecules depending on factors like life style and metabolic capability to degrade the potential harmful substances. Hence, risk assessment of the actual impact of discharges to marine biota should consider these essential biological and ecological factors.

Artificial blood-flow controlling effects of inhomogeneity of twisted magnetic fields

NASA Astrophysics Data System (ADS)

Nakagawa, Hidenori; Ohuchi, Mikio

2017-06-01

We developed a blood-flow controlling system using magnetic therapy for some types of nervous diseases. In our research, we utilized overlapped extremely low frequency (ELF) fields for the most effective blood-flow for the system. Results showed the possibility that the inhomogeneous region obtained by overlapping the fields at 50 Hz, namely, a desirably twisted field revealed a significant difference in induced electromotive forces at the insertion points of electrodes. In addition, ELF exposures with a high inhomogeneity of the twisted field at 50 Hz out of phase were more effective in generating an induced electromotive difference by approximately 31%, as contrasted with the difference generated by the exposure in phase. We expect that the increase of the inhomogeneity of the twisted field around a blood vessel can produce the most effective electromotive difference in the blood, and also moderately affect the excitable cells relating to the autonomic nervous system for an outstanding blood-flow control in vivo.

Variability of pesticide exposure in a stream mesocosm system: macrophyte-dominated vs. non-vegetated sections.

PubMed

Beketov, Mikhail A; Liess, Matthias

2008-12-01

For flowing water bodies no information is available about patterns of contaminant distribution in flowing water compared to macrophyte-dominated structures. The aim of the study was to examine temporal dynamic and spatial cross-channel variability of pulse exposure of the insecticide thiacloprid in outdoor stream mesocosms. Two distinct cross-channel sections have been considered: macrophyte-dominated littoral and non-vegetated midstream. Median disappearance time ranged from 17 to 43 h (water phase, midstream). We showed that during the exposure pulse (10h) thiacloprid concentrations in the macrophyte-dominated section were 20-60% lower than those in the non-vegetated section. This suggests that spatial variability in contaminant concentrations, particularly in streams containing macrophytes, should be taken into account to enable a more realistic assessment of (i) exposure and associated effects and (ii) mass transport of pesticides and other chemicals into river systems (e.g. losses with surface runoff).

International Space Station (ISS)

NASA Image and Video Library

2003-01-16

In this International Space Station (ISS) onboard photo, Expedition Six Science Officer Donald R. Pettit works to set up the Pulmonary Function in Flight (PuFF) experiment hardware in the Destiny Laboratory. Expedition Six is the fourth and final crew to perform the PuFF experiment. The PuFF experiment was developed to better understand what effects long term exposure to microgravity may have on the lungs. The focus is on measuring changes in the everness of gas exchange in the lungs, and on detecting changes in respiratory muscle strength. It allows astronauts to measure blood flow through the lungs, the ability of the lung to take up oxygen, and lung volumes. Each PuFF session includes five lung function tests, which involve breathing only cabin air. For each planned extravehicular (EVA) activity, a crew member performs a PuFF test within one week prior to the EVA. Following the EVA, those crew members perform another test to document the effect of exposure of the lungs to the low-pressure environment of the space suits. This experiment utilizes the Gas Analyzer System for Metabolic Analysis Physiology, or GASMAP, located in the Human Research Facility (HRF), along with a variety of other Puff equipment including a manual breathing valve, flow meter, pressure-flow module, pressure and volume calibration syringes, and disposable mouth pieces.

Pulmonary Function in Flight (PuFF) Experiment

NASA Technical Reports Server (NTRS)

2003-01-01

In this International Space Station (ISS) onboard photo, Expedition Six Science Officer Donald R. Pettit works to set up the Pulmonary Function in Flight (PuFF) experiment hardware in the Destiny Laboratory. Expedition Six is the fourth and final crew to perform the PuFF experiment. The PuFF experiment was developed to better understand what effects long term exposure to microgravity may have on the lungs. The focus is on measuring changes in the everness of gas exchange in the lungs, and on detecting changes in respiratory muscle strength. It allows astronauts to measure blood flow through the lungs, the ability of the lung to take up oxygen, and lung volumes. Each PuFF session includes five lung function tests, which involve breathing only cabin air. For each planned extravehicular (EVA) activity, a crew member performs a PuFF test within one week prior to the EVA. Following the EVA, those crew members perform another test to document the effect of exposure of the lungs to the low-pressure environment of the space suits. This experiment utilizes the Gas Analyzer System for Metabolic Analysis Physiology, or GASMAP, located in the Human Research Facility (HRF), along with a variety of other Puff equipment including a manual breathing valve, flow meter, pressure-flow module, pressure and volume calibration syringes, and disposable mouth pieces.

Dielectrophoretic Field-Flow Fractionation System for Detection of Aquatic Toxicants

PubMed Central

Pui-ock, Sittisak; Ruchirawat, Mathuros; Gascoyne, Peter

2009-01-01

Dielectrophoretic field-flow fractionation (dFFF) was applied as a contact-free way to sense changes in the plasma membrane capacitances and conductivities of cultured human HL-60 cells in response to toxicant exposure. A micropatterned electrode imposed electric forces on cells in suspension in a parabolic flow profile as they moved through a thin chamber. Relative changes in the dFFF peak elution time, reflecting changes in cell membrane area and ion permeability, were measured as indices of response during the first 150 min of exposure to eight toxicants having different single or mixed modes of action (acrylonitrile, actinomycin D, carbon tetrachloride, endosulfan, N-nitroso-N-methylurea (NMU), paraquat dichloride, puromycin, and styrene oxide). The dFFF method was compared with the cell viability assay for all toxicants and with the mitochondrial potentiometric dye assay or DNA alkaline comet assay according to the mode of action of the specific agents. Except for low doses of nucleic acid-targeting agents (actinomycin D and NMU), the dFFF method detected all toxicants more sensitively than other assays, in some cases up to 105 times more sensitively than the viability approach. The results suggest the dFFF method merits additional study for possible applicability in toxicology. PMID:18788754

Operations planning simulation model extension study. Volume 1: Long duration exposure facility ST-01-A automated payload

NASA Technical Reports Server (NTRS)

Marks, D. A.; Gendiellee, R. E.; Kelly, T. M.; Giovannello, M. A.

1974-01-01

Ground processing and operation activities for selected automated and sortie payloads are evaluated. Functional flow activities are expanded to identify payload launch site facility and support requirements. Payload definitions are analyzed from the launch site ground processing viewpoint and then processed through the expanded functional flow activities. The requirements generated from the evaluation are compared with those contained in the data sheets. The following payloads were included in the evaluation: Long Duration Exposure Facility; Life Sciences Shuttle Laboratory; Biomedical Experiments Scientific Satellite; Dedicated Solar Sortie Mission; Magnetic Spectrometer; and Mariner Jupiter Orbiter. The expanded functional flow activities and descriptions for the automated and sortie payloads at the launch site are presented.

Flows of engineered nanomaterials through the recycling process in Switzerland.

PubMed

Caballero-Guzman, Alejandro; Sun, Tianyin; Nowack, Bernd

2015-02-01

The use of engineered nanomaterials (ENMs) in diverse applications has increased during the last years and this will likely continue in the near future. As the number of applications increase, more and more waste with nanomaterials will be generated. A portion of this waste will enter the recycling system, for example, in electronic products, textiles and construction materials. The fate of these materials during and after the waste management and recycling operations is poorly understood. The aim of this work is to model the flows of nano-TiO2, nano-ZnO, nano-Ag and CNT in the recycling system in Switzerland. The basis for this study is published information on the ENMs flows on the Swiss system. We developed a method to assess their flow after recycling. To incorporate the uncertainties inherent to the limited information available, we applied a probabilistic material flow analysis approach. The results show that the recycling processes does not result in significant further propagation of nanomaterials into new products. Instead, the largest proportion will flow as waste that can subsequently be properly handled in incineration plants or landfills. Smaller fractions of ENMs will be eliminated or end up in materials that are sent abroad to undergo further recovery processes. Only a reduced amount of ENMs will flow back to the productive process of the economy in a limited number of sectors. Overall, the results suggest that risk assessment during recycling should focus on occupational exposure, release of ENMs in landfills and incineration plants, and toxicity assessment in a small number of recycled inputs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pulmonary and Systemic Immune Response to Chronic Lunar Dust Inhalation

NASA Technical Reports Server (NTRS)

Crucian, Brian; Quiriarte, Heather; Nelman, Mayra; Lam, Chiu-wing; James, John T.; Sams, Clarence

2014-01-01

Background: Due to millennia of meteorite impact with virtually no erosive effects, the surface of the Moon is covered by a layer of ultra-fine, reactive Lunar dust. Very little is known regarding the toxicity of Lunar dust on human physiology. Given the size and electrostatic characteristics of Lunar dust, countermeasures to ensure non-exposure of astronauts will be difficult. To ensure astronaut safety during any future prolonged Lunar missions, it is necessary to establish the effect of chronic pulmonary Lunar dust exposure on all physiological systems. Methods: This study assessed the toxicity of airborne lunar dust exposure in rats on pulmonary and system immune system parameters. Rats were exposed to 0, 20.8, or 60.8 mg/m3 of lunar dust (6h/d; 5d/wk) for up to 13 weeks. Sacrifices occurred after exposure durations of 1day, 7 days, 4 weeks and 13 weeks post-exposure, when both blood and lung lavage fluid were collected for analysis. Lavage and blood assays included leukocyte distribution by flow cytometry, electron/fluorescent microscopy, and cytokine concentration. Cytokine production profiles following mitogenic stimulation were performed on whole blood only. Results: Untreated lavage fluid was comprised primarily of pulmonary macrophages. Lunar dust inhalation resulted in an influx of neutrophils and lymphocytes. Although the percentage of lymphocytes increased, the T cell CD4:CD8 ratio was unchanged. Cytokine analysis of the lavage fluid showed increased levels of IL-1b and TNFa. These alterations generally persisted through the 13 week sampling. Blood analysis showed few systemic effects from the lunar dust inhalation. By week 4, the peripheral granulocyte percentage was elevated in the treated rats. Plasma cytokine levels were unchanged in all treated rats compared to controls. Peripheral blood analysis showed an increased granulocyte percentage and altered cytokine production profiles consisting of increased in IL-1b and IL-6, and decreased IL-2 production. Conclusion: Lunar dust inhalation results in significant lung inflammation, and some systemic effects, that does not resolve through 13 weeks. Lunar dust may therefore represent a crew health risk during sortie or long-duration Lunar missions.

[Electromagnetic hazards from electrosurgery--assessment of occupational exposure to electromagnetic field and currents induceed in the body].

PubMed

Gryz, Krzysztof; Karpowicz, Jolanta

2006-01-01

The investigation of the occupational exposure to electromagnetic fields from electrosurgery devices were done (according to the requirements of Polish Standard PN-T-06580:2002). The exposure was evaluated following the criteria established by occupational safety and health regulations. The measurements and evaluation of the currents flowing through the exposed workers body were also conducted following the method and criteria published by IEEE standard and European Directive 2004/40/EC. It was found that in the vicinity of electrosurgical devices, the area of electromagnetic fields to which only workers operating the source of field should be exposed can exist up to the distance of 70 cm from the active electrode and supplying cables. In the case when the cables are placed directly on the surgeon body or long duration of the daily exposure the overexposure of workers can appear (referring to Polish regulations). The current flowing through the arm of surgeon keeping the electrode with electric field of the maximum strength (app. 1000 V/m or higher) can exceed permissible value of 40 mA established by the Directive 2004/40/EC for contact current. The reduction of the surgeon exposure can be reached by the proper positioning of the cables supplying monopolar electrode or by the use of bipolar electrode.

Effect of wood smoke exposure on vascular function and thrombus formation in healthy fire fighters.

PubMed

Hunter, Amanda L; Unosson, Jon; Bosson, Jenny A; Langrish, Jeremy P; Pourazar, Jamshid; Raftis, Jennifer B; Miller, Mark R; Lucking, Andrew J; Boman, Christoffer; Nyström, Robin; Donaldson, Kenneth; Flapan, Andrew D; Shah, Anoop S V; Pung, Louis; Sadiktsis, Ioannis; Masala, Silvia; Westerholm, Roger; Sandström, Thomas; Blomberg, Anders; Newby, David E; Mills, Nicholas L

2014-12-09

Myocardial infarction is the leading cause of death in fire fighters and has been linked with exposure to air pollution and fire suppression duties. We therefore investigated the effects of wood smoke exposure on vascular vasomotor and fibrinolytic function, and thrombus formation in healthy fire fighters. In a double-blind randomized cross-over study, 16 healthy male fire fighters were exposed to wood smoke (~1 mg/m³ particulate matter concentration) or filtered air for one hour during intermittent exercise. Arterial pressure and stiffness were measured before and immediately after exposure, and forearm blood flow was measured during intra-brachial infusion of endothelium-dependent and -independent vasodilators 4-6 hours after exposure. Thrombus formation was assessed using the ex vivo Badimon chamber at 2 hours, and platelet activation was measured using flow cytometry for up to 24 hours after the exposure. Compared to filtered air, exposure to wood smoke increased blood carboxyhaemoglobin concentrations (1.3% versus 0.8%; P < 0.001), but had no effect on arterial pressure, augmentation index or pulse wave velocity (P > 0.05 for all). Whilst there was a dose-dependent increase in forearm blood flow with each vasodilator (P < 0.01 for all), there were no differences in blood flow responses to acetylcholine, sodium nitroprusside or verapamil between exposures (P > 0.05 for all). Following exposure to wood smoke, vasodilatation to bradykinin increased (P = 0.003), but there was no effect on bradykinin-induced tissue-plasminogen activator release, thrombus area or markers of platelet activation (P > 0.05 for all). Wood smoke exposure does not impair vascular vasomotor or fibrinolytic function, or increase thrombus formation in fire fighters. Acute cardiovascular events following fire suppression may be precipitated by exposure to other air pollutants or through other mechanisms, such as strenuous physical exertion and dehydration.

LIFE-CYCLE TOXICITY OF BIS(TRIBUTYLTIN) OXIDE TO THE SHEEPSHEAD MINNOW (CYPRINODON VARIEGATUS)

EPA Science Inventory

The effects of tributyltin (TBT) to the life cycle of the estuarine fish C yprinodon variegatus were examined in a 180-day flow-through exposure. The study was initiated with embryos less than 24 h postfertilization and monitored through hatch, maturation, growth, and reproductio...

A Gas Chromatographic System for the Detection of Ethylene Gas Using Ambient Air as a Carrier Gas

PubMed Central

Zaidi, Nayyer Abbas; Tahir, Muhammad Waseem; Vellekoop, Michael J.; Lang, Walter

2017-01-01

Ethylene gas is a naturally occurring gas that has an influence on the shelf life of fruit during their transportation in cargo ships. An unintentional exposure of ethylene gas during transportation results in a loss of fruit. A gas chromatographic system is presented here for the detection of ethylene gas. The gas chromatographic system was assembled using a preconcentrator, a printed 3D printed gas chromatographic column, a humidity sensor, solenoid valves, and an electrochemical ethylene gas sensor. Ambient air was used as a carrier gas in the gas chromatographic system. The flow rate was fixed to 10 sccm. It was generated through a mini-pump connected in series with a mass flow controller. The metal oxide gas sensor is discussed with its limitation in ambient air. The results show the chromatogram obtained from metal oxide gas sensor has low stability, drifts, and has uncertain peaks, while the chromatogram from the electrochemical sensor is stable and precise. Furthermore, ethylene gas measurements at higher ppb concentration and at lower ppb concentration were demonstrated with the electrochemical ethylene gas sensor. The system separates ethylene gas and humidity. The chromatograms obtained from the system are stable, and the results are 1.2% repeatable in five similar measurements. The statistical calculation of the gas chromatographic system shows that a concentration of 2.3 ppb of ethylene gas can be detected through this system. PMID:28991173

Evaluation of air-liquid interface exposure systems for in vitro ...

EPA Pesticide Factsheets

Exposure of cells to airborne pollutants at the air-liquid interface (ALI) is a more realistic approach than exposures of submerged cells. The published literature, however, describes irreproducible and/or unrealistic experimental conditions using ALI systems. We have compared five ALI systems for their ability to deliver both particulate matter (PM) and gases to cells cultured on porous membrane inserts. The ALI systems use different mechanisms to deliver pollutants to the inserts: diffusion, sedimentation, electrostatic precipitation (ESP), and thermophoresis (THP). We used fluorescent polystyrene latex spheres (PSLs) as a surrogate for PM to assess the efficacy of particle deposition in each system. PM loading in each insert was determined by dissolving the PSLs in ethyl acetate and measuring the fluorescence. Results show that using ESP as an external force enhances deposition of 50-nm PSLs by 5.5-fold and 11-fold for 1-µm PSLs when compared to diffusion alone. Similarly, THP enhances deposition of 50-nm and 1-µm PSLs by 4.5-fold and 2.7-fold, respectively. The interaction of ozone with an indigo dye on the surface of the insert showed that diffusion alone permitted gas-cell interaction. For each system there were various design and operational factors, such as the flow rate, surface materials and flow path geometry that adversely affected performance. Increased flow rates correlated with increased efficacy of the systems to deliver the gas to the inserts.

Uptake and Disposition of Select Pharmaceuticals by Bluegill Exposed at Constant Concentrations in a Flow-Through Aquatic Exposure System.

PubMed

Zhao, Jian-Liang; Furlong, Edward T; Schoenfuss, Heiko L; Kolpin, Dana W; Bird, Kyle L; Feifarek, David J; Schwab, Eric A; Ying, Guang-Guo

2017-04-18

The increasing use of pharmaceuticals has led to their subsequent input into and release from wastewater treatment plants, with corresponding discharge into surface waters that may subsequently exert adverse effects upon aquatic organisms. Although the distribution of pharmaceuticals in surface water has been extensively studied, the details of uptake, internal distribution, and kinetic processing of pharmaceuticals in exposed fish have received less attention. For this research, we investigated the uptake, disposition, and toxicokinetics of five pharmaceuticals (diclofenac, methocarbamol, rosuvastatin, sulfamethoxazole, and temazepam) in bluegill sunfish (Lepomis macrochirus) exposed to environmentally relevant concentrations (1000-4000 ng L -1 ) in a flow-through exposure system. Temazepam and methocarbamol were consistently detected in bluegill biological samples with the highest concentrations in bile of 4, 940, and 180 ng g -1 , respectively, while sulfamethoxazole, diclofenac, and rosuvastatin were only infrequently detected. Over 30-day exposures, the relative magnitude of mean concentrations of temazepam and methocarbamol in biological samples generally followed the order: bile ≫ gut > liver and brain > muscle, plasma, and gill. Ranges of bioconcentration factors (BCFs) in different biological samples were 0.71-3960 and 0.13-48.6 for temazepam and methocarbamol, respectively. Log BCFs were statistically positively correlated to pH adjusted log K ow (that is, log D ow ), with the strongest relations for liver and brain (r 2 = 0.92 and 0.99, respectively), implying that bioconcentration patterns of ionizable pharmaceuticals depend on molecular status, that is, whether a pharmaceutical is un-ionized or ionized at ambient tissue pH. Methocarbamol and temazepam underwent rapid uptake and elimination in bluegill biological compartments with uptake rate constants (K u ) and elimination rate constants (K e ) at 0.0066-0.0330 h -1 and 0.0075-0.0384 h -1 , respectively, and half-lives at 18.1-92.4 h. Exposure to mixtures of diclofenac, methocarbamol, sulfamethoxazole, and temazepam had little or no influence on the uptake and elimination rates, suggesting independent multiple uptake and disposition behaviors of pharmaceuticals by fish would occur when exposed to effluent-influenced surface waters.

Uptake and disposition of select pharmaceuticals by bluegill exposed at constant concentrations in a flow-through aquatic exposure system

USGS Publications Warehouse

Zhao, Jian-Liang; Furlong, Edward T.; Schoenfuss, Heiko L.; Kolpin, Dana W.; Bird, Kyle L.; Feifarek, David J.; Schwab, Eric A.; Ying, Guang-Guo

2017-01-01

The increasing use of pharmaceuticals has led to their subsequent input into and release from wastewater treatment plants, with corresponding discharge into surface waters that may subsequently exert adverse effects upon aquatic organisms. Although the distribution of pharmaceuticals in surface water has been extensively studied, the details of uptake, internal distribution, and kinetic processing of pharmaceuticals in exposed fish have received less attention. For this research, we investigated the uptake, disposition, and toxicokinetics of five pharmaceuticals (diclofenac, methocarbamol, rosuvastatin, sulfamethoxazole, and temazepam) in bluegill sunfish (Lepomis macrochirus) exposed to environmentally relevant concentrations (1000–4000 ng L–1) in a flow-through exposure system. Temazepam and methocarbamol were consistently detected in bluegill biological samples with the highest concentrations in bile of 4, 940, and 180 ng g–1, respectively, while sulfamethoxazole, diclofenac, and rosuvastatin were only infrequently detected. Over 30-day exposures, the relative magnitude of mean concentrations of temazepam and methocarbamol in biological samples generally followed the order: bile ≫ gut > liver and brain > muscle, plasma, and gill. Ranges of bioconcentration factors (BCFs) in different biological samples were 0.71–3960 and 0.13–48.6 for temazepam and methocarbamol, respectively. Log BCFs were statistically positively correlated to pH adjusted log Kow (that is, log Dow), with the strongest relations for liver and brain (r2 = 0.92 and 0.99, respectively), implying that bioconcentration patterns of ionizable pharmaceuticals depend on molecular status, that is, whether a pharmaceutical is un-ionized or ionized at ambient tissue pH. Methocarbamol and temazepam underwent rapid uptake and elimination in bluegill biological compartments with uptake rate constants (Ku) and elimination rate constants (Ke) at 0.0066–0.0330 h–1 and 0.0075–0.0384 h–1, respectively, and half-lives at 18.1–92.4 h. Exposure to mixtures of diclofenac, methocarbamol, sulfamethoxazole, and temazepam had little or no influence on the uptake and elimination rates, suggesting independent multiple uptake and disposition behaviors of pharmaceuticals by fish would occur when exposed to effluent-influenced surface waters.

Characterization of a Head-Only Aerosol Exposure System for Nonhuman Primates

DTIC Science & Technology

2010-01-01

Alicat Scientific). The flow used provided isokinetic sampling, assuming the presence of laminar flow at the filter inlet, so that the chamber...airflow measured at the chamber inlet using a Gilibrator flow meter (Sensidyne LP) was 29.79±0.88L/min (n= 10; CV=2.97%). With both the aerosol

A Microfluidic Interface for the Culture and Sampling of Adiponectin from Primary Adipocytes

PubMed Central

Godwin, Leah A.; Brooks, Jessica C.; Hoepfner, Lauren D.; Wanders, Desiree; Judd, Robert L.; Easley, Christopher J.

2014-01-01

Secreted from adipose tissue, adiponectin is a vital endocrine hormone that acts in glucose metabolism, thereby establishing its crucial role in diabetes, obesity, and other metabolic disease states. Insulin exposure to primary adipocytes cultured in static conditions has been shown to stimulate adiponectin secretion. However, conventional, static methodology for culturing and stimulating adipocytes falls short of truly mimicking physiological environments. Along with decreases in experimental costs and sample volume, and increased temporal resolution, microfluidic platforms permit small-volume flowing cell culture systems, which more accurately represent the constant flow conditions through vasculature in vivo. Here, we have integrated a customized primary tissue culture reservoir into a passively operated microfluidic device made of polydimethylsiloxane (PDMS). Fabrication of the reservoir was accomplished through unique PDMS “landscaping” above sampling channels, with a design strategy targeted to primary adipocytes to overcome issues of positive cell buoyancy. This reservoir allowed three-dimensional culture of primary murine adipocytes, accurate control over stimulants via constant perfusion, and sampling of adipokine secretion during various treatments. As the first report of primary adipocyte culture and sampling within microfluidic systems, this work sets the stage for future studies in adipokine secretion dynamics. PMID:25423362

77 FR 20079 - Self-Regulatory Organizations; NYSE Arca, Inc.; Notice of Filing of Proposed Rule Change Relating...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-03

... dependent, and a majority of annual cash flow is earned during the winter heating season (October through... markets in which they invest), to manage cash flows, to limit exposure to losses due to changes to non-U.S... terms of voting rights, liquidation preference, and distributions. However, rather than receiving cash...

Persistence of baroreceptor control of cerebral blood flow velocity at a simulated altitude of 5000 m.

PubMed

Passino, Claudio; Cencetti, Simone; Spadacini, Giammario; Quintana, Robert; Parker, Daryl; Robergs, Robert; Appenzeller, Otto; Bernardi, Luciano

2007-09-01

To assess the effects of acute exposure to simulated high altitude on baroreflex control of mean cerebral blood flow velocity (MCFV). We compared beat-to-beat changes in RR interval, arterial blood pressure, mean MCFV (by transcranial Doppler velocimetry in the middle cerebral artery), end-tidal CO2, oxygen saturation and respiration in 19 healthy subjects at baseline (Albuquerque, 1779 m), after acute exposure to simulated high altitude in a hypobaric chamber (barometric pressure as at 5000 m) and during oxygen administration (to achieve 100% oxygen saturation) at the same barometric pressure (HOX). Baroreflex control on each signal was assessed by univariate and bivariate power spectral analysis performed on time series obtained during controlled (15 breaths/min) breathing, before and during baroreflex modulation induced by 0.1-Hz sinusoidal neck suction. At baseline, neck suction was able to induce a clear increase in low-frequency power in MCFV (P<0.001) as well as in RR and blood pressure. At high altitude, MCFV, as well as RR and blood pressure, was still able to respond to neck suction (all P<0.001), compared to controlled breathing alone, despite marked decreases in end-tidal CO2 and oxygen saturation at high altitude. A similar response was obtained at HOX. Phase delay analysis excluded a passive transmission of low-frequency oscillations from arterial pressure to cerebral circulation. During acute exposure to high altitude, cerebral blood flow is still modulated by the autonomic nervous system through the baroreflex, whose sensitivity is not affected by changes in CO2 and oxygen saturation levels.

Flows of engineered nanomaterials through the recycling process in Switzerland

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

Caballero-Guzman, Alejandro; Sun, Tianyin; Nowack, Bernd, E-mail: nowack@empa.ch

Highlights: • Recycling is one of the likely end-of-life fates of nanoproducts. • We assessed the material flows of four nanomaterials in the Swiss recycling system. • After recycling, most nanomaterials will flow to landfills or incineration plants. • Recycled construction waste, plastics and textiles may contain nanomaterials. - Abstract: The use of engineered nanomaterials (ENMs) in diverse applications has increased during the last years and this will likely continue in the near future. As the number of applications increase, more and more waste with nanomaterials will be generated. A portion of this waste will enter the recycling system, formore » example, in electronic products, textiles and construction materials. The fate of these materials during and after the waste management and recycling operations is poorly understood. The aim of this work is to model the flows of nano-TiO{sub 2}, nano-ZnO, nano-Ag and CNT in the recycling system in Switzerland. The basis for this study is published information on the ENMs flows on the Swiss system. We developed a method to assess their flow after recycling. To incorporate the uncertainties inherent to the limited information available, we applied a probabilistic material flow analysis approach. The results show that the recycling processes does not result in significant further propagation of nanomaterials into new products. Instead, the largest proportion will flow as waste that can subsequently be properly handled in incineration plants or landfills. Smaller fractions of ENMs will be eliminated or end up in materials that are sent abroad to undergo further recovery processes. Only a reduced amount of ENMs will flow back to the productive process of the economy in a limited number of sectors. Overall, the results suggest that risk assessment during recycling should focus on occupational exposure, release of ENMs in landfills and incineration plants, and toxicity assessment in a small number of recycled inputs.« less

Influence of the pineal gland and melatonin on blood flow and evaporative water loss during heat stress in rats.

PubMed

Harlow, H J

1987-01-01

Plasma melatonin levels of laboratory rats were elevated both during acute heat exposure (43 degrees C for 40 min) and chronic exposure (33 degrees C for 17 days) suggesting a possible correlation between melatonin and thermoregulatory mechanisms. Pinealectomy reduced the nighttime elevation in oxygen consumption and evaporative water loss. In addition, pinealectomized animals exhibited a significantly lower cutaneous evaporative water loss both at night and during the day when exposed to an acute heat exposure of 38 degrees C for 45 min. Pinealectomy elevated the blood pressure over the control group whereas melatonin infusion depressed the blood pressure without altering the cardiac output. This relationship implies an action by melatonin on the peripheral vasculature. In support of this conclusion, melatonin pretreatment tended to dampen the vasopressive effect of infused norepinephrine. These data, therefore, suggest a role of the pineal gland and melatonin in thermoregulation through an influence on the cardiovascular system and evaporative water loss.

Mercury-binding proteins in the slipper limpet, Crepidula fornicata, exposed to increased soluble mercury

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

Harrison, F.L.; Watness, K.; Nelson, D.A.

1987-03-01

Crepidula fornicata were held in a flow-through bioassay system and exposed to sand-filtered seawater to which no soluble mercury (control) was added or to which either 5, 25, or 50 {mu}g l{sup {minus}1} soluble Hg was added. At specific intervals during the 16-week experiment, a group of limpets was removed from each tank; one subgroup was exposed for 48 h to high concentrations of Hg, and another was analyzed for Hg-binding proteins by gel-permeation chromatography and spectrometry. Mortality from exposure to Hg in the 48-Hg acute toxicity tests was related to concentrations of Hg experienced both during the long-term exposuremore » period and the 48-h exposure period. Chronic exposure to low levels of Hg resulted in increased amounts of total Hg in the whole body and in the low-molecular-weight Hg-binding proteins. No evidence was found for increased tolerance of Hg with preexposure.« less

Interchangeable whole-body and nose-only exposure system

DOEpatents

Cannon, W.C.; Allemann, R.T.; Moss, O.R.; Decker, J.R. Jr.

1992-03-31

An exposure system for experimental animals includes a container for a single animal which has a double wall. The animal is confined within the inner wall. Gaseous material enters a first end, flows over the entire animal, then back between the walls and out the first end. The system also includes an arrangement of valve-controlled manifolds for supplying gaseous material to, and exhausting it from, the containers. 6 figs.

Interchangeable whole-body and nose-only exposure system

DOEpatents

Cannon, William C.; Allemann, Rudolph T.; Moss, Owen R.; Decker, Jr., John R.

1992-01-01

An exposure system for experimental animals includes a container for a single animal which has a double wall. The animal is confined within the inner wall. Gaseous material enters a first end, flows over the entire animal, then back between the walls and out the first end. The system also includes an arrangement of valve-controlled manifolds for supplying gaseous material to, and exhausting it from, the containers.

NASA Non-Flow-Through PEM Fuel Cell System for Aerospace Applications

NASA Technical Reports Server (NTRS)

Araghi, Koorosh R.

2011-01-01

NASA is researching passive NFT Proton Exchange Membrane (PEM) fuel cell technologies for primary fuel cell power plants in air-independent applications. NFT fuel cell power systems have a higher power density than flow through systems due to both reduced parasitic loads and lower system mass and volume. Reactant storage still dominates system mass/volume considerations. NFT fuel cell stack testing has demonstrated equivalent short term performance to flow through stacks. More testing is required to evaluate long-term performance.

77 FR 1633 - Bacillus Subtilis Strain CX-9060; Exemption From the Requirement of a Tolerance

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-11

... Classification System (NAICS) codes have been provided to assist you and others in determining whether this... other exposures for which there is reliable information.'' This includes exposure through drinking water... exposure to the pesticide through food, drinking water, and through other exposures that occur as a result...

Hydrothermal Circulation Within and Between Basement Outcrops on a Young Ridge Flank: Numerical Models and Thermal Constraints

NASA Astrophysics Data System (ADS)

Hutnak, M.; Fisher, A. T.; Stauffer, P.; Gable, C. W.

2005-12-01

We use two-dimensional, finite-element models of coupled heat and fluid flow to investigate local and large-scale heat and fluid transport around and between basement outcrops on a young ridge flank. System geometries and properties are based on observations and measurements on the 3.4-3.6 Ma eastern flank of the Juan de Fuca Ridge. A small area of basement exposure (Baby Bare outcrop) experiences focused hydrothermal discharge, whereas a much larger feature (Grizzly Bare outcrop) 50 km to the south is a site of hydrothermal recharge. Observations of seafloor heat flow, subseafloor pressures, and basement fluid geochemistry at and near these outcrops constrain acceptable model results. Single-outcrop simulations suggest that local convection alone (represented by a high Nusselt number proxy) cannot explain the near-outcrop heat flow patterns; rapid through-flow is required. Venting of at least 5 L/s through the smaller outcrop, a volumetric flow rate consistent with earlier estimates based on plume and outcrop measurements, is needed to match seafloor heat flow patterns. Heat flow patterns are more variable and complex near the larger, recharging outcrop. Simulations that include 5-20 L/s of recharge through this feature can replicate first-order trends in the data, but small-scale variations are likely to result from heterogeneous flow paths and vigorous, local convection. Two-outcrop simulations started with a warm hydrostatic initial condition, based on a conductive model, result in rapid fluid flow from the smaller outcrop to the larger outcrop, inconsistent with observations. Flow can be sustained in the opposite (correct) direction if it is initially forced, which generates a hydrothermal siphon between the two features. Free flow simulations maintain rapid circulation at rates consistent with observations (specific discharge of m/yr to tens of m/yr), provided basement permeability is on the order of 10-10 m2 or greater. Lateral flow rates scale inversely with the thickness of the permeable basement layer. The differential pressure needed to drive this circulation, created by the siphon, is on the order of tens to hundreds of kPa, with greater differential pressure needed when basement permeability is lower.

Subchronic JP-8 Jet Fuel Exposure Enhances Vulnerability to Noise-Induced Hearing Loss in Rats

DTIC Science & Technology

2012-01-01

square inch (psi) pressure was attached to the side arm of the Sonomist. At this pressure the spray nozzle developed an air flow of approximately 20...L/min (lpm) through the nebulizer. This air flow coupled with the nebulizer nozzle design created an ultrasonic whistle that aerosolized the droplets...pipe contained the spray pattern. The pipe was reduced in size to accept an orifice plate, which was used to measure flow rate by the pressure drop

Do kinematic metrics of walking balance adapt to perturbed optical flow?

PubMed

Thompson, Jessica D; Franz, Jason R

2017-08-01

Visual (i.e., optical flow) perturbations can be used to study balance control and balance deficits. However, it remains unclear whether walking balance control adapts to such perturbations over time. Our purpose was to investigate the propensity for visuomotor adaptation in walking balance control using prolonged exposure to optical flow perturbations. Ten subjects (age: 25.4±3.8years) walked on a treadmill while watching a speed-matched virtual hallway with and without continuous mediolateral optical flow perturbations of three different amplitudes. Each of three perturbation trials consisted of 8min of prolonged exposure followed by 1min of unperturbed walking. Using 3D motion capture, we analyzed changes in foot placement kinematics and mediolateral sacrum motion. At their onset, perturbations elicited wider and shorter steps, alluding to a more cautious, general anticipatory balance control strategy. As perturbations continued, foot placement tended toward values seen during unperturbed walking while step width variability and mediolateral sacrum motion concurrently increased. Our findings suggest that subjects progressively shifted from a general anticipatory balance control strategy to a reactive, task-specific strategy using step-to-step adjustments. Prolonged exposure to optical flow perturbations may have clinical utility to reinforce reactive, task-specific balance control through training. Copyright © 2017 Elsevier B.V. All rights reserved.

The Bolivar Channel Ecosystem of the Galapagos Marine Reserve: Energy flow structure and role of keystone groups

NASA Astrophysics Data System (ADS)

Ruiz, Diego J.; Wolff, Matthias

2011-08-01

The Bolivar Channel Ecosystem (BCE) is among the most productive zones in the Galapagos Marine Reserve (GMR). It is exposed to relatively cool, nutrient-rich waters of the Cromwell current, which are brought to the photic zone through topographic upwelling. The BCE is characterized by a heterogeneous rocky reef habitat covered by dense algae beds and inhabited by numerous invertebrate and fish species, which represent the food for higher predators including seals and sharks and exploited fish species. In addition, plankton and detritus based food chains channel large amounts of energy through the complex food web. Important emblematic species of the Galapagos archipelagos reside in this area such as the flightless cormorant, the Galapagos penguin and the marine iguanas. A trophic model of BCE was constructed for the habitats < 30 m depth that fringe the west coast of Isabela and east coast of Fernandina islands covering 14% of the total BCE area (44 km 2). The model integrates data sets from sub tidal ecological monitoring and marine vertebrate population monitoring (2004 to 2008) programs of the Charles Darwin Foundation and consists of 30 compartments, which are trophically linked through a diet matrix. Results reveal that the BCE is a large system in terms of flows (38 695 t km - 2 yr - 1 ) comparable to Peruvian Bay Systems of the Humboldt upwelling system. A very large proportion of energy flows from the primary producers (phytoplankton and macro-algae) to the second level and to the detritus pool. Catches are high (54.3 t km - 2 yr - 1 ) and are mainly derived from the second and third trophic levels (mean TL of catch = 2.45) making the fisheries gross efficiency high (0.3%). The system's degree of development seems rather low as indicated by a P/R ratio of 4.19, a low ascendency (37.4%) and a very low Finn's cycling index (1.29%). This is explained by the system's exposure to irregular changes in oceanographic conditions as related to the EL Niño Southern Oscillation. Most important keystone groups of large relative impact over other system compartments are sharks and marine mammals. In addition, the important role of macro-algae, sea stars and urchins, phytoplankton and barracudas should be emphasized for their great contribution to the trophic flows and biomass of the system.

Application of digital interferogram evaluation techniques to the measurement of 3-D flow fields

NASA Technical Reports Server (NTRS)

Becker, Friedhelm; Yu, Yung H.

1987-01-01

A system for digitally evaluating interferograms, based on an image processing system connected to a host computer, was implemented. The system supports one- and two-dimensional interferogram evaluations. Interferograms are digitized, enhanced, and then segmented. The fringe coordinates are extracted, and the fringes are represented as polygonal data structures. Fringe numbering and fringe interpolation modules are implemented. The system supports editing and interactive features, as well as graphic visualization. An application of the system to the evaluation of double exposure interferograms from the transonic flow field around a helicopter blade and the reconstruction of the three dimensional flow field is given.

Modeling of the fate of radionuclides in urban sewer systems after contamination due to nuclear or radiological incidents.

PubMed

Urso, L; Kaiser, J C; Andersson, K G; Andorfer, H; Angermair, G; Gusel, C; Tandler, R

2013-04-01

After an accidental radioactive contamination by aerosols in inhabited areas, the radiation exposure to man is determined by complex interactions between different factors such as dry or wet deposition, different types of ground surfaces, chemical properties of the radionuclides involved and building development as well as dependence on bomb construction e.g. design and geometry. At short-term, the first rainfall is an important way of natural decontamination: deposited radionuclides are washed off from surfaces and in urban areas the resulting contaminated runoff enters the sewer system and is collected in a sewage plant. Up to now the potential exposure caused by this process has received little attention and is estimated here with simulation models. The commercial rainfall-runoff model for urban sewer systems KANAL++ has been extended to include transport of radionuclides from surfaces through the drainage to various discharge facilities. The flow from surfaces is modeled by unit hydrographs, which produce boundary conditions for a system of 1d coupled flow and transport equations in a tube system. Initial conditions are provided by a map of surface contamination which is produced by geo-statistical interpolation of γ-dose rate measurements taking into account the detector environment. The corresponding methodology is implemented in the Inhabited Area Monitoring Module (IAMM) software module as part of the European decision system JRODOS. A hypothetical scenario is considered where a Radiation Dispersal Device (RDD) with Cs-137 is detonated in a small inhabited area whose drainage system is realistically modeled. The transition of deposited radionuclides due to rainfall into the surface runoff is accounted for by different nuclide-specific entrainment coefficients for paved and unpaved surfaces. The concentration of Cs-137 in water is calculated at the nodes of the drainage system and at the sewage treatment plant. The external exposure to staff of the treatment plant is estimated. For Cs-137 radiation levels in the plant are low since wash-off of cesium from surfaces is an ineffective process. Copyright © 2012 Elsevier Ltd. All rights reserved.

Monolithic Integration of a Silicon Nanowire Field-Effect Transistors Array on a Complementary Metal-Oxide Semiconductor Chip for Biochemical Sensor Applications

PubMed Central

Livi, Paolo; Kwiat, Moria; Shadmani, Amir; Pevzner, Alexander; Navarra, Giulio; Rothe, Jörg; Stettler, Alexander; Chen, Yihui; Patolsky, Fernando; Hierlemann, Andreas

2017-01-01

We present a monolithic complementary metal-oxide semiconductor (CMOS)-based sensor system comprising an array of silicon nanowire field-effect transistors (FETs) and the signal-conditioning circuitry on the same chip. The silicon nanowires were fabricated by chemical vapor deposition methods and then transferred to the CMOS chip, where Ti/Pd/Ti contacts had been patterned via e-beam lithography. The on-chip circuitry measures the current flowing through each nanowire FET upon applying a constant source-drain voltage. The analog signal is digitized on chip and then transmitted to a receiving unit. The system has been successfully fabricated and tested by acquiring I−V curves of the bare nanowire-based FETs. Furthermore, the sensing capabilities of the complete system have been demonstrated by recording current changes upon nanowire exposure to solutions of different pHs, as well as by detecting different concentrations of Troponin T biomarkers (cTnT) through antibody-functionalized nanowire FETs. PMID:26348408

Monolithic integration of a silicon nanowire field-effect transistors array on a complementary metal-oxide semiconductor chip for biochemical sensor applications.

PubMed

Livi, Paolo; Kwiat, Moria; Shadmani, Amir; Pevzner, Alexander; Navarra, Giulio; Rothe, Jörg; Stettler, Alexander; Chen, Yihui; Patolsky, Fernando; Hierlemann, Andreas

2015-10-06

We present a monolithic complementary metal-oxide semiconductor (CMOS)-based sensor system comprising an array of silicon nanowire field-effect transistors (FETs) and the signal-conditioning circuitry on the same chip. The silicon nanowires were fabricated by chemical vapor deposition methods and then transferred to the CMOS chip, where Ti/Pd/Ti contacts had been patterned via e-beam lithography. The on-chip circuitry measures the current flowing through each nanowire FET upon applying a constant source-drain voltage. The analog signal is digitized on chip and then transmitted to a receiving unit. The system has been successfully fabricated and tested by acquiring I-V curves of the bare nanowire-based FETs. Furthermore, the sensing capabilities of the complete system have been demonstrated by recording current changes upon nanowire exposure to solutions of different pHs, as well as by detecting different concentrations of Troponin T biomarkers (cTnT) through antibody-functionalized nanowire FETs.

Design of an exposure chamber to test samplers used in the evaluation of personal exposure to nanoparticles

NASA Astrophysics Data System (ADS)

Amin, R.; Izadi, H.; Quémerais, B.

2015-05-01

The aim of this study was to design a laboratory size exposure chamber for the testing of samplers used to collect personal exposure samples for nanoparticles. A polyethylene cylindrical container with a diameter of 42 cm and height of 60 cm was used as the testing chamber. The chamber was divided into 2 parts by an aluminium honey comb. Particles generated using a 1 jet Collison nebulizer (BGI) operating at a flow rate of 4L/min were inserted into the chamber via a tube located near to the top of the chamber. A heater was inserted just after the nebulizer to avoid condensation of water in the tubing, and dilution air, running at 10L/min was inserted just after the heater. As particle charge can dramatically affect sampling a particle neutralizer was attached to the generation system so as to neutralize the particles before they enter the chamber. A diffusion dryer was used to remove any water from the air stream prior to enter the chamber. A fan was used to mix and distribute the generated particles. After generation and mixing, the particles passed through the aluminium honeycomb which is essential to eliminate any turbulent or unwanted air flow. Six sampling ports along with a pressure gauge were placed on the walls 15 cm from the bottom of the chamber. The pressure gauge was added to ensure the desired pressure is achieved during sampling. The sampling ports allowed for the connection of five samplers and sampling pumps as well as the connection of an ultrafine particle counter. The exposure chamber was developed to assess various samplers for carbon nanotubes and cellulose nanocrystals. Results showed that the chamber was working properly and that mixing was sufficiently uniform to test samplers.

Emplacement and dewatering of the world's largest exposed sand injectite complex

NASA Astrophysics Data System (ADS)

Sherry, Timothy J.; Rowe, Christie D.; Kirkpatrick, James D.; Brodsky, Emily E.

2012-08-01

Sandstone injectites form by up or down-section flow of a mobilized sand slurry through fractures in overlying rock. They act as reservoirs and high-permeability conduits through lower permeability rock in hydrocarbon systems. The Yellow Bank Creek Complex, Santa Cruz County, California is the largest known exposure of a sandstone injectite in the world. The complex contains granular textures that record processes of sand slurry flow, multiple pore fluids, and dewatering after emplacement. The injection was initially mobilized from a source containing both water and hydrocarbons. The water-sand slurry reached emplacement depth first, due to lower fluid viscosity. As the sand slurry emplaced, the transition from slurry flow to pore water percolation occurred. This transition resulted in preferred flow channels ˜6 mm wide in which sand grains were weakly aligned (laminae). The hydrocarbon-sand slurry intruded the dewatering sands and locally deformed the laminae. Compaction of the injectite deposit and pore fluid escape caused spaced compaction bands and dewatering pipes which created convolutions of the laminae. The hydrocarbon-rich sand slurry is preserved today as dolomite-cemented sand with oil inclusions. The laminae in this injectite are easily detected due to preferential iron oxide-cementation of the well-aligned sand laminae, and lack of cement in the alternating laminae. Subtle textures like these may develop during sand flow and be present but difficult to detect in other settings. They may explain permeability anisotropy in other sand deposits.

Flood scour monitoring system using fiber Bragg grating sensors

NASA Astrophysics Data System (ADS)

Lin, Yung Bin; Lai, Jihn Sung; Chang, Kuo Chun; Li, Lu Sheng

2006-12-01

The exposure and subsequent undermining of pier/abutment foundations through the scouring action of a flood can result in the structural failure of a bridge. Bridge scour is one of the leading causes of bridge failure. Bridges subject to periods of flood/high flow require monitoring during those times in order to protect the traveling public. In this study, an innovative scour monitoring system using button-like fiber Bragg grating (FBG) sensors was developed and applied successfully in the field during the Aere typhoon period in 2004. The in situ FBG scour monitoring system has been demonstrated to be robust and reliable for real-time scour-depth measurements, and to be valid for indicating depositional depth at the Dadu Bridge. The field results show that this system can function well and survive a typhoon flood.

Effects of Convection During the Photodeposition of Polydiacetylene Thin Films

NASA Technical Reports Server (NTRS)

Frazier, D. O.; Hung, R. J.; Paley, M. S.; Long, Y. T.

1997-01-01

In this work, we describe a preliminary investigation of buoyancy-driven heat transfer during the growth of thin films from solution following exposure to ultraviolet (UV) light. Irradiation of the growth cell occurs at various directions relative to gravitational acceleration. Through numerical computations, the steady-state flow and temperature profiles are simulated during the course of light exposure. Light-induced polymerization accompanies a heat transfer process through a fairly complicated recirculating flow pattern. A scaling analysis shows that buoyancy-driven velocities only reduce by a factor of 10 for gravity levels as low as 10(exp -2)g(sub 0). Paley et al. observe what appears to be gravitationally sensitive particle development and inclusion in thin films using a photodeposition process. From this study it is clear that production of homogeneous thin films would have to occur in the environment of a complicated flow pattern of recirculation with a nonuniform temperature distribution. Indeed, even when irradiation occurs from the top of the cell, the most stable stratified cell orientation, defects remain in our films due to the persistence of buoyancy-driven convection. To achieve homogeneity, minimal scattering centers, and possible molecular order, photodeposition of polymer films by UV light exposure must proceed in a reduced-convection environment. Fluid mechanics simulations are useful for establishing gravitational sensitivity to this recently discovered process (patent # 5,451,433) for preparing thin films having quite promising nonlinear optical characteristics.

Effects of Convection during the Photodeposition of Polydiacetylene Thin Films

NASA Technical Reports Server (NTRS)

Frazier, D. O.; Hung, R. J.; Paley, M. S.; Long, Y. T.

1997-01-01

In this work, we describe a preliminary investigation of buoyancy-driven heat transfer during the growth of thin films from solution following exposure to ultraviolet (UV) light. Irradiation of the growth cell occurs at various directions relative to gravitational acceleration. Through numerical computations, the steady-state flow and temperature profiles are simulated during the course of light exposure. Light-induced polymerization accompanies a heat transfer process through a fairly complicated recirculating flow pattern. A scaling analysis shows that buoyancy-driven velocities only reduce by a factor of 10 for gravity levels as low as 10(exp -2) g(sub 0). Paley et al. observe what appears to be gravitationally sensitive particle development and inclusion in thin films using a photodeposition process. From this study, it is clear that production of homogeneous thin films would have to occur in the environment of a complicated flow pattern of recirculation with a nonuniform temperature distribution. Indeed, even when irradiation occurs from the top of the cell, the most stable stratified cell orientation, defects remain in our films due to the persistence of buoyancy-driven convection. To achieve homogeneity, minimal scattering centers, and possible molecular order, photodeposition of polymer films by UV light exposure must proceed in a reduced-convection environment. Fluid mechanics simulations are useful for establishing gravitational sensitivity to this recently discovered process (patent # 5,451,433) for preparing thin films having quite promising nonlinear optical characteristics.

Chronic toxicity of hydrogen peroxide to Daphnia magna in a continuous exposure, flow-through test system

USGS Publications Warehouse

Meinertz, J.R.; Greseth, Shari L.; Gaikowski, M.P.; Schmidt, L.J.

2008-01-01

A flow-through, continuous exposure test system was developed to expose Daphnia magna to an unstable compound. 35% Perox-Aid?? is a specially formulated hydrogen peroxide (a highly oxidative chemical) product approved for use in U.S. aquaculture and therefore has the potential to be released from aquaculture facilities and pose a risk to aquatic invertebrates. The study objective was to assess the effects of 35% Perox-Aid?? on an aquatic invertebrate by evaluating the survival, growth, production, and gender ratio of progeny from a representative aquatic invertebrate continuously exposed to 35% Perox-Aid??. The study design consisted of 6 treatment groups (10 test chambers each) with target hydrogen peroxide concentrations of 0.0, 0.32, 0.63, 1.25, 2.5, and 5.0??mg L- 1. The study was initiated with < 24-h-old Daphnia (1 daphnid per chamber) that were exposed to hydrogen peroxide for 21??days. Hydrogen peroxide concentrations ??? 1.25??mg L- 1 had no significant effect on Daphnia time to death compared to controls and no significant effect on the time to first brood production and the number of broods produced. Concentrations ??? 0.63??mg L- 1 had no significant effect on the total number of young produced. Concentrations ??? 0.32??mg L- 1 had a negative effect on Daphnia growth. Hydrogen peroxide had no significant effect on the gender ratio of young produced. All second generation Daphnia were female. A continuous discharge of hydrogen peroxide into aquatic ecosystems is not likely to affect cladocerans if the concentration is maintained at ??? 0.63??mg L- 1 for less than 21??days.

EXPOSURE ASSESSMENT MODELING FOR HYDROCARBON SPILLS INTO THE SUBSURFACE

EPA Science Inventory

Hydrocarbons which enter the subsurface through spills or leaks may create serious, long-lived ground-water contamination problems. onventional finite difference and finite element models of multiphase, multicomponent flow often have extreme requirements for both computer time an...

Survivability and Abiotic Reactions of Selected Amino Acids in Different Hydrothermal System Simulators

NASA Astrophysics Data System (ADS)

Chandru, Kuhan; Imai, Eiichi; Kaneko, Takeo; Obayashi, Yumiko; Kobayashi, Kensei

2013-04-01

We tested the stability and reaction of several amino acids using hydrothermal system simulators: an autoclave and two kinds of flow reactors at 200-250 °C. This study generally showed that there is a variation in the individual amino acids survivability in the simulators. This is mainly attributed to the following factors; heat time, cold quenching exposure, metal ions and also silica. We observed that, in a rapid heating flow reactor, high aggregation and/or condensation of amino acids could occur even during a heat exposure of 2 min. We also monitored their stability in a reflow-type of simulator for 120 min at 20 min intervals. The non-hydrolyzed and hydrolyzed samples for this system showed a similar degradation only in the absence of metal ions.

Moisture effects in heat transfer through clothing systems for wildland firefighters.

PubMed

Lawson, Lelia K; Crown, Elizabeth M; Ackerman, Mark Y; Dale, J Douglas

2004-01-01

Wildland firefighters work in unfavourable environments involving both heat and moisture. Moisture in clothing systems worn by wildland firefighters may increase or decrease heat transfer, depending on its source and location in the clothing system, location on the body, timing of application and degree of sorption. In this experiment, 4 outerwear/underwear combinations were exposed to 1 of 5 different conditions varying on amount and location of moisture. The fabric systems were then exposed to either a high-heat-flux flame exposure (83 kW/m(2)) or a low-heat-flux radiant exposure (10 kW/m(2)). Under high-heat-flux flame exposures, external moisture tended to decrease heat transfer through the fabric systems, while internal moisture tended to increase heat transfer. Under low-heat-flux radiant exposures, internal moisture decreased heat transfer through the fabric systems. The nature and extent of such differences was fabric dependent. Implications for test protocol development are discussed.

Timing and nature of alluvial fan development along the Chajnantor Plateau, northern Chile

NASA Astrophysics Data System (ADS)

Cesta, Jason M.; Ward, Dylan J.

2016-11-01

Alluvial systems in the Atacama Desert provide a unique opportunity to elucidate the sedimentary response to climate variability, particularly changes in precipitation, in hyperarid environments. Alluvial fans along the eastern margin of the Salar de Atacama, adjacent to the Chajnantor Plateau in the Atacama Desert of northern Chile, provide an archive of climate-modulated sediment transfer and erosion at an extreme of Earth's climate. Three regional alluvial fan surfaces (Qf1 [oldest] to Qf3 [youngest]) were mapped along the western flank of the Chajnantor Plateau. The alluvial fans were examined with geomorphic and terrestrial cosmogenic 36Cl surface exposure dating methods to define the timing of alluvial fan formation and to determine the role of climatic processes on fan development in a hyperarid environment. Alluvial fans in the study area are comprised of hyperconcentrated flow and boulder-rich debris flow deposits that reflect deposition transitioning between cohesive and noncohesive regimes. Alluvial fan surfaces yield exposure ages that range from 49.6 ± 4.4 to 194 ± 12 ka, while debris flow boulders yield exposure ages ranging from 12.4 ± 2.1 to 229 ± 53 ka. Cosmogenic 36Cl exposure ages indicate that abandonment of alluvial fan surfaces Qf1, Qf2, and Qf3 date to 175 ± 22.6 ka (MIS 6), 134.5 ± 9.18 ka (MIS 6), and 20.07 ± 6.26 ka (MIS 2), respectively. A 36Cl concentration-depth profile through alluvial fan Qf1 suggests a simple depositional history with minimal nuclide inheritance implying relatively rapid aggradation (6 m in ca. 25 kyr) followed by surface abandonment ca. 180-200 ka. Our data support a strong climatic control on alluvial fan evolution in the region, and we propose that the alluvial fans along the margins of the Salar de Atacama form according to the humid model of fan formation.

Determining the effects of a mixture of an endocrine disrupting compound, 17α-ethinylestradiol, and ammonia on fathead minnow (Pimephales promelas) reproduction.

PubMed

Armstrong, Brandon M; Lazorchak, James M; Murphy, Cheryl A; Haring, Herman J; Jensen, Kathleen M; Smith, Mark E

2015-02-01

Aquatic organisms are exposed to a multitude of contaminants and to fully understand the impact of multiple stressors on fish populations, we must first understand the mechanism of action for each toxicant and how the combined effects manifest at the level of the individual. 17α-ethinylestradiol (EE2) has been known to cause adverse reproductive effects including reduced fecundity and fertility, intersex and skewed sex ratios in fish by mimicking naturally produced estrogen at low concentrations. Ammonia can cause adverse reproductive and mortality effects in individual fish through effects or damage to the central nervous system. Both EE2 and ammonia are found in most municipal effluents in various concentrations. A flow-through diluter system was used to test the individual effects of these two contaminants at their respective no observable adverse effect concentration (NOAEC) as well as their combined effects on fathead minnow, (Pimephales promelas) reproduction in a mixture exposure. While neither contaminant nor their mixture altered reproduction in terms of fecundity, their mixture resulted in significant fathead minnow mortality during a 21 d exposure. This study demonstrated the need to consider mixture effects when assessing risk for toxicity testing with multiple stressors. Published by Elsevier Ltd.

Flow-through Fourier transform infrared sensor for total hydrocarbons determination in water.

PubMed

Pérez-Palacios, David; Armenta, Sergio; Lendl, Bernhard

2009-09-01

A new flow-through Fourier transform infrared (FT-IR) sensor for oil in water analysis based on solid-phase spectroscopy on octadecyl (C18) silica particles has been developed. The C18 non-polar sorbent is placed inside the sensor and is able to retain hydrocarbons from water samples. The system does not require the use of chlorinated solvents, reducing the environmental impact, and the minimal sample handling stages serve to ensure sample integrity whilst reducing exposure of the analyst to any toxic hydrocarbons present within the samples. Fourier transform infrared (FT-IR) spectra were recorded by co-adding 32 scans at a resolution of 4 cm(-1) and the band located at 1462 cm(-1) due to the CH(2) bending was integrated from 1475 to 1450 cm(-1) using a baseline correction established between 1485 and 1440 cm(-1) using the areas as analytical signal. The technique, which provides a limit of detection (LOD) of 22 mg L(-1) and a precision expressed as relative standard deviation (RSD) lower than 5%, is considerably rapid and allows for a high level of automation.

Exposure setup to study potential adverse effects at GSM 1800 and UMTS frequencies on the auditory systems of rats.

PubMed

Lopresto, V; Pinto, R; De Vita, A; Mancini, S; Galloni, P; Marino, C; Ravazzani, P; Lovisolo, G A

2007-01-01

To investigate possible biological effects of exposure to electromagnetic (EM) fields at the frequencies of global system for mobile communication (GSM) 1800 system and universal mobile telecommunication system (UMTS) on the auditory system of rats, an exposure setup for in vivo experiments is presented. The study was carried out in the framework of two European research projects. The target of the investigation was the cochlea. A dosimetric study was performed, both numerically and through direct measurements, to assess the interaction of the radiated fields and the dose distribution in the biological target. For the local exposure of rats, a loop antenna operating at the frequency bands of interest was designed, realised and characterised through numerical and experimental dosimetric procedures. Moreover, an exposure apparatus was set up, consisting of three arrays of four loop antennas, placed on three levels, thus allowing simultaneous exposure of 12 rats to give statistical power to the experiments. To isolate the exposure arrays, the setup was assembled by a wooden rack with EM field absorbing panels, inserted among the levels and at the four sides of the rack. Isolation was verified by direct measurements. Two exposure arrays were simultaneously supplied, whereas the third one was used for sham exposure. Blind exposure was achieved through a black box, hiding physical connections to the microwave power supply. During exposure sessions, rats were restrained in special plastic jigs for repeatable positioning, thus assuring the fixed level of dose in the target.

Neural Correlates of Exposure to Traumatic Pictures and Sound in Vietnam Combat Veterans with and without Posttraumatic Stress Disorder: A Positron Emission Tomography Study

PubMed Central

Bremner, J. Douglas; Staib, Lawrence H.; Kaloupek, Danny; Southwick, Steven M.; Soufer, Robert; Charney, Dennis S.

2011-01-01

Background Patients with posttraumatic stress disorder (PTSD) show a reliable increase in PTSD symptoms and physiological reactivity following exposure to traumatic pictures and sounds. In this study neural correlates of exposure to traumatic pictures and sounds were measured in PTSD. Methods Positron emission tomography and H2[15O] were used to measure cerebral blood flow during exposure to combat-related and neutral pictures and sounds in Vietnam combat veterans with and without PTSD. Results Exposure to traumatic material in PTSD (but not non-PTSD) subjects resulted in a decrease in blood flow in medial prefrontal cortex (area 25), an area postulated to play a role in emotion through inhibition of amygdala responsiveness. Non-PTSD subjects activated anterior cingulate (area 24) to a greater degree than PTSD patients. There were also differences in cerebral blood flow response in areas involved in memory and visuospatial processing (and by extension response to threat), including posterior cingulate (area 23), precentral (motor) and inferior parietal cortex, and lingual gyrus. There was a pattern of increases in PTSD and decreases in non-PTSD subjects in these areas. Conclusions The findings suggest that functional alterations in specific cortical and subcortical brain areas involved in memory, visuospatial processing, and emotion underlie the symptoms of patients with PTSD. PMID:10202567

Flow through electrode with automated calibration

DOEpatents

Szecsody, James E [Richland, WA; Williams, Mark D [Richland, WA; Vermeul, Vince R [Richland, WA

2002-08-20

The present invention is an improved automated flow through electrode liquid monitoring system. The automated system has a sample inlet to a sample pump, a sample outlet from the sample pump to at least one flow through electrode with a waste port. At least one computer controls the sample pump and records data from the at least one flow through electrode for a liquid sample. The improvement relies upon (a) at least one source of a calibration sample connected to (b) an injection valve connected to said sample outlet and connected to said source, said injection valve further connected to said at least one flow through electrode, wherein said injection valve is controlled by said computer to select between said liquid sample or said calibration sample. Advantages include improved accuracy because of more frequent calibrations, no additional labor for calibration, no need to remove the flow through electrode(s), and minimal interruption of sampling.

Occupational exposure to plant protection products and health effects in Switzerland: what do we know and what do we need to do?

PubMed

Graczyk, Halshka; Hopf, Nancy B; Mediouni, Zakia; Guseva-Canu, Irina; Sanvido, Olivier; Schmid, Kaspar; Berthet, Aurelie

2018-04-26

There is currently no centralised database on workers' exposures to plant protection products (PPPs) in Switzerland, nor a national register for negative health effects linking them to occupational PPP exposure. This lack of basic data makes it difficult to implement either epidemiological research or prevention campaigns for the agricultural sector. The first objective was to understand the level of information and flow of data on occupational PPP exposures and health effects in the Canton of Vaud, Switzerland. Then, to apply this information to develop recommendations for improving a vigilance system for occupational health effects related to PPP exposure. A mapping study and semistructured stakeholder interviews were conducted to better understand the flow of data on occupational PPP exposures and health effects. A clinical records investigation of workers occupationally exposed to PPPs was undertaken to understand the magnitude of this potential problem. Finally, a workshop brought together relevant stakeholders to discuss recommendations for the way forwards. A lack of data on PPP exposures and associated health effects was revealed. This highlighted important knowledge gaps at different levels of the current institutional information flow system. We found that although there were numerous stakeholders that worked efficiently in their own mandate, there was a clear need for increased collaboration and coordination in order to make use of existing data to promote safer PPP use among agricultural workers in Switzerland. Due to increasing evidence of an association between PPP exposure and health effects, increased collaboration between stakeholders is necessary to develop links between the data sources that already exist. Our study was the first to investigate the health effects linked to PPP exposure among the Swiss agricultural population. The recommendations presented in this paper would help promote a safer and healthier agricultural workforce in Switzerland, as well as the population at large.

20 CFR 652.204 - Must funds authorized under section 7(b) of the Act (the Governor's reserve) flow through the One...

Code of Federal Regulations, 2010 CFR

2010-04-01

... the Act (the Governor's reserve) flow through the One-Stop delivery system? 652.204 Section 652.204... FUNCTIONING OF STATE EMPLOYMENT SERVICES Wagner-Peyser Act Services in a One-Stop Delivery System Environment § 652.204 Must funds authorized under section 7(b) of the Act (the Governor's reserve) flow through the...

Characterization and testing of amidoxime-based adsorbent materials to extract uranium from natural seawater

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

Kuo, Li-Jung; Janke, Christopher James; Wood, Jordana

Extraction of uranium (U) from seawater for use as a nuclear fuel is a significant challenge due to the low concentration of U in seawater (~3.3 ppb) and difficulties to selectively extract U from the background of major and trace elements in seawater. The Pacific Northwest National Laboratory (PNNL) s Marine Sciences Laboratory (MSL) has been serving as a marine test site for determining performance characteristics (adsorption capacity, adsorption kinetics, and selectivity) of novel amidoxime-based polymeric adsorbents developed at Oak Ridge National Laboratory (ORNL) under natural seawater exposure conditions. This report describes the performance of three formulations (38H, AF1, AI8)more » of amidoxime-based polymeric adsorbent produced at ORNL in MSL s ambient seawater testing facility. The adsorbents were produced in two forms, fibrous material (40-100 mg samples) and braided material (5-10 g samples), exposed to natural seawater using flow-through columns and recirculating flumes. All three formulations demonstrated high 56 day uranium adsorption capacity (>3 gU/kg adsorbent). The AF1 formulation had the best uranium adsorption performance, with 56-day capacity of 3.9 g U/kg adsorbent, saturation capacity of 5.4 g U/kg adsorbent, and ~25 days half-saturation time. The two exposure methods, flow-through columns and flumes were demonstrated to produce similar performance results, providing confidence that the test methods were reliable, that scaling up from 10 s of mg quantities of exposure in flow-through columns to gram quantities in flumes produced similar results, and that the manufacturing process produces a homogenous adsorbent. Adsorption kinetics appear to be element specific, with half-saturation times ranging from minutes for the major cations in seawater to 8-10weeks for V and Fe. Reducing the exposure time provides a potential pathway to improve the adsorption capacity of U by reducing the V/U ratio on the adsorbent.« less

Characterization and testing of amidoxime-based adsorbent materials to extract uranium from natural seawater

DOE PAGES

Kuo, Li-Jung; Janke, Christopher James; Wood, Jordana; ...

2015-11-19

Extraction of uranium (U) from seawater for use as a nuclear fuel is a significant challenge due to the low concentration of U in seawater (~3.3 ppb) and difficulties to selectively extract U from the background of major and trace elements in seawater. The Pacific Northwest National Laboratory (PNNL) s Marine Sciences Laboratory (MSL) has been serving as a marine test site for determining performance characteristics (adsorption capacity, adsorption kinetics, and selectivity) of novel amidoxime-based polymeric adsorbents developed at Oak Ridge National Laboratory (ORNL) under natural seawater exposure conditions. This report describes the performance of three formulations (38H, AF1, AI8)more » of amidoxime-based polymeric adsorbent produced at ORNL in MSL s ambient seawater testing facility. The adsorbents were produced in two forms, fibrous material (40-100 mg samples) and braided material (5-10 g samples), exposed to natural seawater using flow-through columns and recirculating flumes. All three formulations demonstrated high 56 day uranium adsorption capacity (>3 gU/kg adsorbent). The AF1 formulation had the best uranium adsorption performance, with 56-day capacity of 3.9 g U/kg adsorbent, saturation capacity of 5.4 g U/kg adsorbent, and ~25 days half-saturation time. The two exposure methods, flow-through columns and flumes were demonstrated to produce similar performance results, providing confidence that the test methods were reliable, that scaling up from 10 s of mg quantities of exposure in flow-through columns to gram quantities in flumes produced similar results, and that the manufacturing process produces a homogenous adsorbent. Adsorption kinetics appear to be element specific, with half-saturation times ranging from minutes for the major cations in seawater to 8-10weeks for V and Fe. Reducing the exposure time provides a potential pathway to improve the adsorption capacity of U by reducing the V/U ratio on the adsorbent.« less

Test and evaluation of constant-flow devices for use in SSN AFFF proportioning systems. Interim report, January-May 1986

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

Williams, F.W.; Back, G.G.; Burns, R.E.

1986-11-04

Constant flow devices, which deliver a constant flow of liquid over a range of upstream and downstream pressures, have been suggested as an alternative to orifice plates for proportioning AFFF in SSN 21 fire-suppression systems. Operational and performance characteristics of two lightweight, inexpensive, commercially available constant-flow devices have significant advantages over orifice plates. Both models tested, however, showed performance degradation when subjected to simulated service conditions. A constant flow device with improved resistance to wear and to AFFF exposure is desirable. Since the constant-flow control devices tested improves proportioning efficiency but do not have optimum characteristics, investigation of improved devicesmore » or methods is recommended.« less

Cooling system having dual suction port compressor

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

Wu, Guolian

2017-08-29

A cooling system for appliances, air conditioners, and other spaces includes a compressor, and a condenser that receives refrigerant from the compressor. The system also includes an evaporator that receives refrigerant from the condenser. Refrigerant received from the condenser flows through an upstream portion of the evaporator. A first portion of the refrigerant flows to the compressor without passing through a downstream portion of the evaporator, and a second portion of the refrigerant from the upstream portion of the condenser flows through the downstream portion of the evaporator after passing through the upstream portion of the evaporator. The second portionmore » of the refrigerant flows to the compressor after passing through the downstream portion of the evaporator. The refrigeration system may be configured to cool an appliance such as a refrigerator and/or freezer, or it may be utilized in air conditioners for buildings, motor vehicles, or other such spaces.« less

Refrigeration system having dual suction port compressor

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

Wu, Guolian

A cooling system for appliances, air conditioners, and other spaces includes a compressor, and a condenser that receives refrigerant from the compressor. The system also includes an evaporator that receives refrigerant from the condenser. Refrigerant received from the condenser flows through an upstream portion of the evaporator. A first portion of the refrigerant flows to the compressor without passing through a downstream portion of the evaporator, and a second portion of the refrigerant from the upstream portion of the condenser flows through the downstream portion of the evaporator after passing through the upstream portion of the evaporator. The second portionmore » of the refrigerant flows to the compressor after passing through the downstream portion of the evaporator. The refrigeration system may be configured to cool an appliance such as a refrigerator and/or freezer, or it may be utilized in air conditioners for buildings, motor vehicles, or other such spaces.« less

Modeling of skin cooling, blood flow, and optical properties in wounds created by electrical shock

NASA Astrophysics Data System (ADS)

Nguyen, Thu T. A.; Shupp, Jeffrey W.; Moffatt, Lauren T.; Jordan, Marion H.; Jeng, James C.; Ramella-Roman, Jessica C.

2012-02-01

High voltage electrical injuries may lead to irreversible tissue damage or even death. Research on tissue injury following high voltage shock is needed and may yield stage-appropriate therapy to reduce amputation rate. One of the mechanisms by which electricity damages tissue is through Joule heating, with subsequent protein denaturation. Previous studies have shown that blood flow had a significant effect on the cooling rate of heated subcutaneous tissue. To assess the thermal damage in tissue, this study focused on monitoring changes of temperature and optical properties of skin next to high voltage wounds. The burns were created between left fore limb and right hind limb extremities of adult male Sprague-Dawley rats by a 1000VDC delivery shock system. A thermal camera was utilized to record temperature variation during the exposure. The experimental results were then validated using a thermal-electric finite element model (FEM).

Effect of Direct Glare on Orbicularis Oculi and Trapezius During Computer Reading.

PubMed

Mork, Randi; Bruenech, Jan Richard; Thorud, Hanne Mari Schiøtz

2016-07-01

Unfavorable visual conditions during computer work may affect development of both eyestrain and musculoskeletal pain in the neck and shoulder area. The aim of the study was to investigate how direct glare affects symptom development, muscle activity, and muscle blood flow in m. orbicularis oculi and m. trapezius during reading on a computer screen. Fifteen healthy young adults with normal binocular vision read text on a computer screen at an optimized computer workplace, 30 minutes with glare exposure and 30 minutes with appropriate lighting. Postural angles were continuously registered. Development of eye symptoms and musculoskeletal pain in the neck and shoulder area were recorded using VAS scales. Muscle activity and muscle blood flow were measured continuously using electromyography and photoplethysmography, respectively. Glare exposure resulted in significantly more pronounced eye pain, increased orbicularis muscle activity, and increased trapezius blood flow compared to reading with appropriate lighting. There were no significant differences in posture between the two light conditions. There were also significant associations between orbicularis oculi activity and both trapezius blood flow and neck pain during both conditions. Results from the current study show that direct glare conditions cause increased eyestrain and orbicularis oculi contraction during reading on a computer screen. This study also indicates that exposure to direct glare affects the trapezius muscle, possibly by an interaction between the visual system, sympathetic nervous system, and head-stabilizing muscles. In addition, there were associations between the use of orbicularis oculi, trapezius blood flow, and development of neck pain independent of the lighting.

Hemolysis in a laminar flow-through Couette shearing device: an experimental study.

PubMed

Boehning, Fiete; Mejia, Tzahiry; Schmitz-Rode, Thomas; Steinseifer, Ulrich

2014-09-01

Reducing hemolysis has been one of the major goals of rotary blood pump development and in the investigational phase, the capability of hemolysis estimation for areas of elevated shear stresses is valuable. The degree of hemolysis is determined by the amplitude of shear stress and the exposure time, but to date, the exact hemolytic behavior at elevated shear stresses and potential thresholds for subcritical shear exposure remain vague. This study provides experimental hemolysis data for a set of shear stresses and exposure times to allow better estimations of hemolysis for blood exposed to elevated shearing. Heparinized porcine blood with a hematocrit of 40% was mechanically damaged in a flow-through laminar Couette shear flow at a temperature of 23°C. Four levels of shear stress, 24, 592, 702, and 842 Pa, were replicated at two exposure times, 54 and 873 ms. For the calculation of the shear stresses, an apparent viscosity of 5 mPas was used, which was verified in an additional measurement of the blood viscosity. The hemolysis measurements were repeated four times, whereby all conditions were measured once within the same day and with blood from the same source. Samples were taken at the inlet and outlet of the shear region and an increase in plasma-free hemoglobin was measured. An index of hemolysis (IH) was thereby calculated giving the ratio of free to total hemoglobin. The results are compared with data from previously published studies using a similar shearing device. Hemolysis was found to increase exponentially with shear stress, but high standard deviations existed at measurements with elevated IH. At short exposure times, the IH remained low at under 0.5% for all shear stress levels. For high exposure times, the IH increased from 0.84% at 592 Pa up to 3.57% at the highest shear stress level. Hemolysis was significant for shear stresses above ∼600 Pa at the high exposure time of 873 ms. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Vascular and Inflammatory Factors in the Pathophysiology of Blast-Induced Brain Injury

PubMed Central

Elder, Gregory A.; Gama Sosa, Miguel A.; De Gasperi, Rita; Stone, James Radford; Dickstein, Dara L.; Haghighi, Fatemeh; Hof, Patrick R.; Ahlers, Stephen T.

2015-01-01

Blast-related traumatic brain injury (TBI) has received much recent attention because of its frequency in the conflicts in Iraq and Afghanistan. This renewed interest has led to a rapid expansion of clinical and animal studies related to blast. In humans, high-level blast exposure is associated with a prominent hemorrhagic component. In animal models, blast exerts a variety of effects on the nervous system including vascular and inflammatory effects that can be seen with even low-level blast exposures which produce minimal or no neuronal pathology. Acutely, blast exposure in animals causes prominent vasospasm and decreased cerebral blood flow along with blood-brain barrier breakdown and increased vascular permeability. Besides direct effects on the central nervous system, evidence supports a role for a thoracically mediated effect of blast; whereby, pressure waves transmitted through the systemic circulation damage the brain. Chronically, a vascular pathology has been observed that is associated with alterations of the vascular extracellular matrix. Sustained microglial and astroglial reactions occur after blast exposure. Markers of a central and peripheral inflammatory response are found for sustained periods after blast injury and include elevation of inflammatory cytokines and other inflammatory mediators. At low levels of blast exposure, a microvascular pathology has been observed in the presence of an otherwise normal brain parenchyma, suggesting that the vasculature may be selectively vulnerable to blast injury. Chronic immune activation in brain following vascular injury may lead to neurobehavioral changes in the absence of direct neuronal pathology. Strategies aimed at preventing or reversing vascular damage or modulating the immune response may improve the chronic neuropsychiatric symptoms associated with blast-related TBI. PMID:25852632

A review of mass and energy flow through a lava flow system: insights provided from a non-equilibrium perspective

NASA Astrophysics Data System (ADS)

Tarquini, Simone

2017-08-01

A simple formula relates lava discharge rate to the heat radiated per unit time from the surface of active lava flows (the "thermal proxy"). Although widely used, the physical basis of this proxy is still debated. In the present contribution, lava flows are approached as open, dissipative systems that, under favorable conditions, can attain a non-equilibrium stationary state. In this system framework, the onset, growth, and demise of lava flow units can be explained as a self-organization phenomenon characterized by a given temporal frequency defined by the average life span of active lava flow units. Here, I review empirical, physical, and experimental models designed to understand and link the flow of mass and energy through a lava flow system, as well as measurements and observations that support a "real-world" view. I set up two systems: active lava flow system (or ALFS) for flowing, fluid lava and a lava deposit system for solidified, cooling lava. The review highlights surprising similarities between lava flows and electric currents, which typically work under stationary conditions. An electric current propagates almost instantaneously through an existing circuit, following the Kirchhoff law (a least dissipation principle). Flowing lavas, in contrast, build up a slow-motion "lava circuit" over days, weeks, or months by following a gravity-driven path down the steepest slopes. Attainment of a steady-state condition is hampered (and the classic thermal proxy does not hold) if the supply stops before completion of the "lava circuit." Although gravity determines initial flow path and extension, the least dissipation principle means that subsequent evolution of mature portions of the active lava flow system is controlled by increasingly insulated conditions.

Detection of early changes in lung cell cytology by flow-systems analysis techniques

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

Steinkamp, J.A.; Hansen, K.M.; Wilson, J.S.

1976-12-01

This report summarizes results of continuing experiments to develop cytological and biochemical indicators for estimating damage to respiratory cells in test animals exposed by inhalation to toxic agents associated with nonnuclear energy production, the specific goal being the application of advanced multiparameter flow-systems technologies to the detection of early atypical cellular changes in lung epithelium. Normal Syrian hamster lung cell samples composed of macrophages, leukocytes, ciliated columnar cells, and epithelial cells were stained with fluorescent dyes specific for different biochemical parameters and were analyzed in liquid suspension as they flowed through a chamber intersecting a laser beam of exciting light.more » Multiple sensors measured the total or two-color fluorescence and light scatter on a cell-by-cell basis. Cellular parameters proportional to optical measurements (i.e., cell size, DNA content, total protein, nonspecific esterase activity, nuclear and cytoplasmic diameters) were displayed as frequency distribution histograms. Lung cell samples were also separated according to various cytological parameters and identified microscopically. The basic operating features of the methodology are discussed briefly, along with specific examples of preliminary results illustrating the initial characterization of exfoliated pulmonary cells from normal hamsters. As the flow technology is adapted further to the analysis of respiratory cells, measurements of changes in physical and biochemical properties as a function of exposure to toxic agents will be performed.« less

Procedure for Evaluating the Effects of 2,450- Megahertz Microwaves upon Streptococcus faecalis and Saccharomyces cerevisiae1

PubMed Central

Lechowich, R. V.; Beuchat, L. R.; Fox, K. I.; Webster, F. H.

1969-01-01

Modifications of a commercial 2,450-megahertz microwave oven were made so that 6 ml of microbial suspension could be exposed to the microwave field for various periods of time. The microorganisms were contained in the central tube of a modified Liebig condenser positioned in the approximate geometric center of the oven cavity. Kerosene at -25 C was circulated through the jacket of the condenser during microwave exposure permitting microwaves to reach the microbial suspension. Flow rates of the kerosene were varied to permit the temperature of the suspension to range from 25 to 55 C during microwave exposure. Conductive heating experiments using similar temperatures were also conducted. A thermocouple-relay system was employed to measure the suspension temperature immediately after the magnetron shutoff. Continuous application of microwaves to suspensions of 108 to 109 Streptococcus faecalis or Saccharomyces cerevisiae per ml appeared to produce no lethal effects other than those produced by heat. Respiration rates of microwave-exposed Scerevisiae were directly related to decreases in viable count produced by increased microwave exposure times. Images PMID:4975450

Exposure Assessment for Carbon Dioxide Gas: Full Shift Average and Short-Term Measurement Approaches.

PubMed

Hill, R Jedd; Smith, Philip A

2015-01-01

Carbon dioxide (CO2) makes up a relatively small percentage of atmospheric gases, yet when used or produced in large quantities as a gas, a liquid, or a solid (dry ice), substantial airborne exposures may occur. Exposure to elevated CO2 concentrations may elicit toxicity, even with oxygen concentrations that are not considered dangerous per se. Full-shift sampling approaches to measure 8-hr time weighted average (TWA) CO2 exposures are used in many facilities where CO2 gas may be present. The need to assess rapidly fluctuating CO2 levels that may approach immediately dangerous to life or health (IDLH) conditions should also be a concern, and several methods for doing so using fast responding measurement tools are discussed in this paper. Colorimetric detector tubes, a non-dispersive infrared (NDIR) detector, and a portable Fourier transform infrared (FTIR) spectroscopy instrument were evaluated in a laboratory environment using a flow-through standard generation system and were found to provide suitable accuracy and precision for assessing rapid fluctuations in CO2 concentration, with a possible effect related to humidity noted only for the detector tubes. These tools were used in the field to select locations and times for grab sampling and personal full-shift sampling, which provided laboratory analysis data to confirm IDLH conditions and 8-hr TWA exposure information. Fluctuating CO2 exposures are exemplified through field work results from several workplaces. In a brewery, brief CO2 exposures above the IDLH value occurred when large volumes of CO2-containing liquid were released for disposal, but 8-hr TWA exposures were not found to exceed the permissible level. In a frozen food production facility nearly constant exposure to CO2 concentrations above the permissible 8-hr TWA value were seen, as well as brief exposures above the IDLH concentration which were associated with specific tasks where liquid CO2 was used. In a poultry processing facility the use of dry ice to quickly freeze product produced a nearly constant CO2 concentration that caused exposures to approach the permissible 8-hr TWA exposure value.

A microfluidic device with multi-valves system to enable several simultaneous exposure tests on Caenorhabditis elegans

NASA Astrophysics Data System (ADS)

Jung, Jaehoon; Nakajima, Masahiro; Masaru, Takeuchi; Huang, Qiang; Fukuda, Toshio

2014-03-01

In this paper, we report on a microfluidic device with a multi-valve system to conduct several exposure tests on Caenorhabditis elegans (C. elegans) simultaneously. It has pneumatic valves and no-moving-parts (NMP) valves. An NMP valve is incorporated with a chamber and enables the unidirectional movement of C. elegans in the chamber; once worms are loaded into the chamber, they cannot exit, regardless of the flow direction. To demonstrate the ability of the NMP valve to handle worms, we made a microfluidic device with three chambers. Each chamber was used to expose worms to Cd and Cu solutions, and K-medium. A pair of electrodes was installed in the device and the capacitance in-between the electrode was measured. When a C. elegans passed through the electrodes, the capacitance was changed. The capacitance change was proportional to the body volume of the worm, thus the body volume change by the heavy metal exposure was measured in the device. Thirty worms were divided into three groups and exposed to each solution. We confirmed that the different solutions induced differences in the capacitance changes for each group. These results indicate that our device is a viable method for simultaneously analyzing the effect of multiple stimuli on C. elegans.

Sealing properties of a self-etching primer system to normal caries-affected and caries-infected dentin.

PubMed

Lee, Kwang-Won; Son, H-H; Yoshiyama, Masatoshi; Tay, Franklin R; Carvalho, Ricardo M; Pashley, David H

2003-09-01

To compare the ability of an experimental antibacterial self-etching primer adhesive system to seal exposure sites in normal, caries-affected and caries-infected human dentin. 30 extracted human third molars were used within 1 month of extraction. 10 intact normal teeth comprised the normal group. 20 teeth with occlusal caries that radiographically extended halfway to the pulp were excavated using caries-detector solution (CDS) and a #4 round carbide bur in a slowspeed handpiece. Half of those teeth were fully excavated free of CDS-stained material without exposing the pulp, and were designated as the caries-affected dentin group. The remaining 10 teeth were excavated as close to the pulp as possible without obtaining an exposure, but whose dentin continued to stain red with CDS; this group was designated as the caries-infected dentin group. The remaining dentin thickness in all of the specimens in the other two groups was then reduced to the same extent as the caries-infected group. Direct exposures of the pulp chamber were made with a 1/4 round bur in the normal dentin or a 25 gauge needle in the other two groups. After measuring the fluid flow through the exposure, the sites were then sealed with an experimental antibacterial fluoride-containing self-etching primer adhesive systems (ABF). Fluid conductance was remeasured every week for 16 weeks. The fluid conductance through the exposure fell 99% in all groups following resin sealing. The seals of normal and caries-affected dentin remained relatively stable over the 16 weeks, while the seals of caries-infected dentin gradually deteriorated, reaching significance at 8 weeks. TEM examination revealed very thin (ca. 0.5 mm) hybrid layers in normal dentin, 3-4 microm thick hybrid layers in caries-affected dentin and 40 microm thick hybrid layers in caries-infected dentin. The tubules of caries-infected dentin were enlarged and filled with bacteria. Resin tags passed around these bacteria in the top 20-40 microm thereby encapsulating them in resin.

Effects of chronic hypoxia on maternal vasodilation and vascular reactivity in guinea pig and ovine pregnancy.

PubMed

White, Margueritte M; Zhang, Lubo

2003-01-01

During pregnancy, exposure to chronic hypoxia is thought to be associated with an increased risk of preeclampsia and fetal intrauterine growth restriction (IUGR). While some studies suggest that this process may be mediated through effects of chronic hypoxia on uterine artery vasodilation and growth, these observations are likely to be species specific and may represent genetic variability in maternal adaptation to hypoxia. This review is a comparative analysis of the effects of chronic hypoxia on vascular reactivity in pregnant and nonpregnant guinea pig and sheep. Data suggest that exposure to chronic hypoxia is associated with enhanced uterine artery blood flow in the sheep, whereas, in the guinea pig, blood flow is decreased.

Human skin in vitro permeation of bentazon and isoproturon formulations with or without protective clothing suit.

PubMed

Berthet, Aurélie; Hopf, Nancy B; Miles, Alexandra; Spring, Philipp; Charrière, Nicole; Garrigou, Alain; Baldi, Isabelle; Vernez, David

2014-01-01

Skin exposures to chemicals may lead, through percutaneous permeation, to a significant increase in systemic circulation. Skin is the primary route of entry during some occupational activities, especially in agriculture. To reduce skin exposures, the use of personal protective equipment (PPE) is recommended. PPE efficiency is characterized as the time until products permeate through material (lag time, Tlag). Both skin and PPE permeations are assessed using similar in vitro methods; the diffusion cell system. Flow-through diffusion cells were used in this study to assess the permeation of two herbicides, bentazon and isoproturon, as well as four related commercial formulations (Basagran(®), Basamais(®), Arelon(®) and Matara(®)). Permeation was measured through fresh excised human skin, protective clothing suits (suits) (Microchem(®) 3000, AgriSafe Pro(®), Proshield(®) and Microgard(®) 2000 Plus Green), and a combination of skin and suits. Both herbicides, tested by itself or as an active ingredient in formulations, permeated readily through human skin and tested suits (Tlag < 2 h). High permeation coefficients were obtained regardless of formulations or tested membranes, except for Microchem(®) 3000. Short Tlag, were observed even when skin was covered with suits, except for Microchem(®) 3000. Kp values tended to decrease when suits covered the skin (except when Arelon(®) was applied to skin covered with AgriSafe Pro and Microgard(®) 2000), suggesting that Tlag alone is insufficient in characterizing suits. To better estimate human skin permeations, in vitro experiments should not only use human skin but also consider the intended use of the suit, i.e., the active ingredient concentrations and type of formulations, which significantly affect skin permeation.

Validation of Noninvasive MOEMS-Assisted Measurement System Based on CCD Sensor for Radial Pulse Analysis

PubMed Central

Malinauskas, Karolis; Palevicius, Paulius; Ragulskis, Minvydas; Ostasevicius, Vytautas; Dauksevicius, Rolanas

2013-01-01

Examination of wrist radial pulse is a noninvasive diagnostic method, which occupies a very important position in Traditional Chinese Medicine. It is based on manual palpation and therefore relies largely on the practitioner′s subjective technical skills and judgment. Consequently, it lacks reliability and consistency, which limits practical applications in clinical medicine. Thus, quantifiable characterization of the wrist pulse diagnosis method is a prerequisite for its further development and widespread use. This paper reports application of a noninvasive CCD sensor-based hybrid measurement system for radial pulse signal analysis. First, artery wall deformations caused by the blood flow are calibrated with a laser triangulation displacement sensor, following by the measurement of the deformations with projection moiré method. Different input pressures and fluids of various viscosities are used in the assembled artificial blood flow system in order to test the performance of laser triangulation technique with detection sensitivity enhancement through microfabricated retroreflective optical element placed on a synthetic vascular graft. Subsequently, the applicability of double-exposure whole-field projection moiré technique for registration of blood flow pulses is considered: a computational model and representative example are provided, followed by in vitro experiment performed on a vascular graft with artificial skin atop, which validates the suitability of the technique for characterization of skin surface deformations caused by the radial pulsation. PMID:23609803

Validation of noninvasive MOEMS-assisted measurement system based on CCD sensor for radial pulse analysis.

PubMed

Malinauskas, Karolis; Palevicius, Paulius; Ragulskis, Minvydas; Ostasevicius, Vytautas; Dauksevicius, Rolanas

2013-04-22

Examination of wrist radial pulse is a noninvasive diagnostic method, which occupies a very important position in Traditional Chinese Medicine. It is based on manual palpation and therefore relies largely on the practitioner's subjective technical skills and judgment. Consequently, it lacks reliability and consistency, which limits practical applications in clinical medicine. Thus, quantifiable characterization of the wrist pulse diagnosis method is a prerequisite for its further development and widespread use. This paper reports application of a noninvasive CCD sensor-based hybrid measurement system for radial pulse signal analysis. First, artery wall deformations caused by the blood flow are calibrated with a laser triangulation displacement sensor, following by the measurement of the deformations with projection moiré method. Different input pressures and fluids of various viscosities are used in the assembled artificial blood flow system in order to test the performance of laser triangulation technique with detection sensitivity enhancement through microfabricated retroreflective optical element placed on a synthetic vascular graft. Subsequently, the applicability of double-exposure whole-field projection moiré technique for registration of blood flow pulses is considered: a computational model and representative example are provided, followed by in vitro experiment performed on a vascular graft with artificial skin atop, which validates the suitability of the technique for characterization of skin surface deformations caused by the radial pulsation.

Sub-lethal glyphosate exposure alters flowering phenology and causes transient male-sterility in Brassica spp

EPA Science Inventory

Herbicide resistance in weedy plant populations can develop through different mechanisms such as gene flow of herbicide resistant transgenes from crop species into compatible weedy species or by natural evolution of herbicide resistance or tolerance following selection pressure. ...

Prevalidation of in vitro continuous flow exposure systems as alternatives to in vivo inhalation safety evaluation experimentations: outcome from MAAPHRI-PCRD5 research program.

PubMed

Morin, Jean-Paul; Hasson, Virginie; Fall, Mamadou; Papaioanou, Eleni; Preterre, David; Gouriou, Frantz; Keravec, Veronika; Konstandopoulos, Athanasios; Dionnet, Frédéric

2008-06-01

Diesel engine emission aerosol-induced toxicity patterns were compared using both in vitro (organotypic cultures of lung tissue) and in vivo experimentations mimicking the inhalation situation with continuous aerosol flow exposure designs. Using liquid media resuspended diesel particles, we show that toxic response pattern is influenced by the presence of tensioactive agent in the medium which alter particle-borne pollutant bioavailability. Using continuous aerosol exposure in vitro, we show that with high sulfur fuel (300ppm) in the absence of oxidation catalysis, particulate matter was the main toxic component triggering DNA damage and systemic inflammation, while a very limited oxidant stress was evidenced. In contrast, with ultra-low sulfur fuel in the presence of strong diesel oxidation catalysis, the specific role of particulate matter is no longer evidenced and the gas phase then becomes the major component triggering strong oxidant stress, increased NO(2) being the most probable trigger. In vivo, plasma tumor necrosis factor alpha (TNFalpha), lung superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activity levels varied in agreement with in vitro observations. Diesel emission treatment with oxycat provokes a marked systemic oxidant stress. Again NO(2) proved to account for a major part of these impacts. In conclusion, similar anti-oxidant responses were observed in in vitro and in vivo experiments after diesel emission aerosol continuous flow exposures. The lung slice organotypic culture model-exposed complex aerosol appears to be a very valuable alternative to in vivo inhalation toxicology experimentations in rodents.

Non-Flow-Through Fuel Cell System Test Results and Demonstration on the SCARAB Rover

NASA Technical Reports Server (NTRS)

Scheidegger, Brianne, T.; Burke, Kenneth A.; Jakupca, Ian J.

2012-01-01

This paper describes the results of the demonstration of a non-flow-through PEM fuel cell as part of a power system on the SCARAB rover. A 16-cell non-flow-through fuel cell stack from Infinity Fuel Cell and Hydrogen, Inc. was incorporated into a power system designed to act as a range extender by providing power to the rover s hotel loads. This work represents the first attempt at a ground demonstration of this new technology aboard a mobile test platform. Development and demonstration were supported by the Office of the Chief Technologist s Space Power Systems Project and the Advanced Exploration System Modular Power Systems Project.

Effects of Pump Pulsation on Hydrodynamic Properties and Dissolution Profiles in Flow-Through Dissolution Systems (USP 4).

PubMed

Yoshida, Hiroyuki; Kuwana, Akemi; Shibata, Hiroko; Izutsu, Ken-Ichi; Goda, Yukihiro

2016-06-01

To clarify the effects of pump pulsation and flow-through cell (FTC) dissolution system settings on the hydrodynamic properties and dissolution profiles of model formulations. Two FTC systems with different cell temperature control mechanisms were used. Particle image velocimetry (PIV) was used to analyze the hydrodynamic properties of test solutions in the flow-through dissolution test cell. Two pulsation pumps (semi-sine, full-sine) and a non-pulsatile pump were used to study the effects of varied flows on the dissolution profiles of United States Pharmacopeia standard tablets. PIV analysis showed periodic changes in the aligned upward fluid flow throughout the dissolution cell that was designed to reduce the temperature gradient during pump pulsation (0.5 s/pulse). The maximum instantaneous flow from the semi-sine pump was higher than that of the full-sine pump under all conditions. The flow from the semi-sine wave pump showed faster dissolution of salicylic acid and prednisone tablets than those from other pumps. The semi-sine wave pump flow showed similar dissolution profiles in the two FTC systems. Variations in instantaneous fluid flow caused by pump pulsation that meets the requirements of pharmacopoeias are a factor that affects the dissolution profiles of tablets in FTC systems.

Medical mitigation model: quantifying the benefits of the public health response to a chemical terrorism attack.

PubMed

Good, Kevin; Winkel, David; VonNiederhausern, Michael; Hawkins, Brian; Cox, Jessica; Gooding, Rachel; Whitmire, Mark

2013-06-01

The Chemical Terrorism Risk Assessment (CTRA) and Chemical Infrastructure Risk Assessment (CIRA) are programs that estimate the risk of chemical terrorism attacks to help inform and improve the US defense posture against such events. One aspect of these programs is the development and advancement of a Medical Mitigation Model-a mathematical model that simulates the medical response to a chemical terrorism attack and estimates the resulting number of saved or benefited victims. At the foundation of the CTRA/CIRA Medical Mitigation Model is the concept of stock-and-flow modeling; "stocks" are states that individuals progress through during the event, while "flows" permit and govern movement from one stock to another. Using this approach, the model is able to simulate and track individual victims as they progress from exposure to an end state. Some of the considerations in the model include chemical used, type of attack, route and severity of exposure, response-related delays, detailed treatment regimens with efficacy defined as a function of time, medical system capacity, the influx of worried well individuals, and medical countermeasure availability. As will be demonstrated, the output of the CTRA/CIRA Medical Mitigation Model makes it possible to assess the effectiveness of the existing public health response system and develop and examine potential improvement strategies. Such a modeling and analysis capability can be used to inform first-responder actions/training, guide policy decisions, justify resource allocation, and direct knowledge-gap studies.

Optimization of camera exposure durations for multi-exposure speckle imaging of the microcirculation

PubMed Central

Kazmi, S. M. Shams; Balial, Satyajit; Dunn, Andrew K.

2014-01-01

Improved Laser Speckle Contrast Imaging (LSCI) blood flow analyses that incorporate inverse models of the underlying laser-tissue interaction have been used to develop more quantitative implementations of speckle flowmetry such as Multi-Exposure Speckle Imaging (MESI). In this paper, we determine the optimal camera exposure durations required for obtaining flow information with comparable accuracy with the prevailing MESI implementation utilized in recent in vivo rodent studies. A looping leave-one-out (LOO) algorithm was used to identify exposure subsets which were analyzed for accuracy against flows obtained from analysis with the original full exposure set over 9 animals comprising n = 314 regional flow measurements. From the 15 original exposures, 6 exposures were found using the LOO process to provide comparable accuracy, defined as being no more than 10% deviant, with the original flow measurements. The optimal subset of exposures provides a basis set of camera durations for speckle flowmetry studies of the microcirculation and confers a two-fold faster acquisition rate and a 28% reduction in processing time without sacrificing accuracy. Additionally, the optimization process can be used to identify further reductions in the exposure subsets for tailoring imaging over less expansive flow distributions to enable even faster imaging. PMID:25071956

Psychophysiological tests and provocation of subjects with mobile phone related symptoms.

PubMed

Wilén, Jonna; Johansson, Amanda; Kalezic, Nebojsa; Lyskov, Eugene; Sandström, Monica

2006-04-01

The aim of the present study was to investigate the effect of exposure to a mobile phone-like radiofrequency (RF) electromagnetic field on persons experiencing subjective symptoms when using mobile phones (MP). Twenty subjects with MP-related symptoms were recruited and matched with 20 controls without MP-related symptoms. Each subject participated in two experimental sessions, one with true exposure and one with sham exposure, in random order. In the true exposure condition, the test subjects were exposed for 30 min to an RF field generating a maximum SAR(1g) in the head of 1 W/kg through an indoor base station antenna attached to a 900 MHz GSM MP. The following physiological and cognitive parameters were measured during the experiment: heart rate and heart rate variability (HRV), respiration, local blood flow, electrodermal activity, critical flicker fusion threshold (CFFT), short-term memory, and reaction time. No significant differences related to RF exposure conditions were detected. Also no differences in baseline data were found between subject groups, except for the reaction time, which was significantly longer among the cases than among the controls the first time the test was performed. This difference disappeared when the test was repeated. However, the cases differed significantly from the controls with respect to HRV as measured in the frequency domain. The cases displayed a shift in low/high frequency ratio towards a sympathetic dominance in the autonomous nervous system during the CFFT and memory tests, regardless of exposure condition. This might be interpreted as a sign of differences in the autonomous nervous system regulation between persons with MP related subjective symptoms and persons with no such symptoms. (c) 2005 Wiley-Liss, Inc.

Effects of oil on internal gas transport, radial oxygen loss, gas films and bud growth in Phragmites australis.

PubMed

Armstrong, Jean; Keep, Rory; Armstrong, William

2009-01-01

Oil pollution of wetlands is a world-wide problem but, to date, research has concentrated on its influences on salt marsh rather than freshwater plant communities. The effects of water-borne light oils (liquid paraffin and diesel) were investigated on the fresh/brackish wetland species Phragmites australis in terms of routes of oil infiltration, internal gas transport, radial O(2) loss (ROL), underwater gas films and bud growth. Pressure flow resistances of pith cavities of nodes and aerenchyma of leaf sheaths, with or without previous exposure to oil, were recorded from flow rates under applied pressure. Convective flows were measured from living excised culms with oiled and non-oiled nodes and leaf sheaths. The effect of oil around culm basal nodes on ROL from rhizome and root apices was measured polarographically. Surface gas films on submerged shoots with and without oil treatment were recorded photographically. Growth and emergence of buds through water with and without an oil film were measured. Internodes are virtually impermeable, but nodes of senesced and living culms are permeable to oils which can block pith cavity diaphragms, preventing flows at applied pressures of 1 kPa, natural convective transport to the rhizome, and greatly decreasing ROL to phyllospheres and rhizospheres. Oil infiltrating or covering living leaf sheaths prevents humidity-induced convection. Oil displaces surface gas films from laminae and leaf sheaths. Buds emerge only a few centimetres through oil and die. Oil infiltrates the gas space system via nodal and leaf sheath stomata, reducing O(2) diffusion and convective flows into the rhizome system and decreasing oxygenation of phyllospheres and rhizospheres; underwater gas exchange via gas films will be impeded. Plants can be weakened by oil-induced failure of emerging buds. Plants will be most at risk during the growing season.

Cold atmospheric pressure air plasma jet for medical applications

NASA Astrophysics Data System (ADS)

Kolb, J. F.; Mohamed, A.-A. H.; Price, R. O.; Swanson, R. J.; Bowman, A.; Chiavarini, R. L.; Stacey, M.; Schoenbach, K. H.

2008-06-01

By flowing atmospheric pressure air through a direct current powered microhollow cathode discharge, we were able to generate a 2cm long plasma jet. With increasing flow rate, the flow becomes turbulent and temperatures of the jet are reduced to values close to room temperature. Utilizing the jet, yeast grown on agar can be eradicated with a treatment of only a few seconds. Conversely, animal studies show no skin damage even with exposures ten times longer than needed for pathogen extermination. This cold plasma jet provides an effective mode of treatment for yeast infections of the skin.

Fault-controlled development of shallow hydrothermal systems: Structural and mineralogical insights from the Southern Andes

NASA Astrophysics Data System (ADS)

Roquer, T.; Arancibia, G.; Rowland, J. V.; Iturrieta, P. C.; Morata, D.; Cembrano, J. M.

2017-12-01

Paleofluid-transporting systems can be recognized as meshes of fracture-filled veins in eroded zones of extinct hydrothermal systems. Here we conducted meso-microstructural analysis and mechanical modeling from two exhumed exposures of the faults governing regional tectonics of the Southern Andes: the Liquiñe-Ofqui Fault System (LOFS) and the Andean Transverse Faults (ATF). A total of 107 fractures in both exposures were analyzed. The ATF specific segment shows two tectonic solutions that can be modeled as Andersonian and non-Andersonian tectonic regimes: (1) shear (mode II/III) failure occurs at differential stresses > 28 MPa and fluid pressures < 40-80% lithostatic in the Andersonian regime; and (2) sporadic hybrid extensional + shear (modes I + II/III) failure occurs at differential stresses < 20 MPa and anomalously high fluid pressures > 85-98% lithostatic in the non-Andersonian regime. Additionally, the LOFS exposure cyclically fails in extension (mode I) or extension + shear (modes I + II/III) in the Andersonian regime, at differential stresses < 28 MPa and fluid pressures > 40-80% lithostatic. In areas of spatial interaction between ATF and LOFS, these conditions might favor: (1) the storage of overpressured fluids in hydrothermal systems associated with the ATF faults, and (2) continuous fluid flow through vertical conduits in the LOFS faults. These observations suggest that such intersections are highly probable locations for concentrated hydrothermal activity, which must be taken into consideration for further geothermal exploration. ACKNOWLEDGEMENTS. PhD CONICYT grants, Centro de Excelencia en Geotermia de los Andes (CEGA-FONDAP/CONICYT Project #15090013), FONDECYT Project #1130030 and Project CONICYT REDES #140036.

Exposure to 1800 MHz radiofrequency electromagnetic radiation induces oxidative DNA base damage in a mouse spermatocyte-derived cell line.

PubMed

Liu, Chuan; Duan, Weixia; Xu, Shangcheng; Chen, Chunhai; He, Mindi; Zhang, Lei; Yu, Zhengping; Zhou, Zhou

2013-03-27

Whether exposure to radiofrequency electromagnetic radiation (RF-EMR) emitted from mobile phones can induce DNA damage in male germ cells remains unclear. In this study, we conducted a 24h intermittent exposure (5 min on and 10 min off) of a mouse spermatocyte-derived GC-2 cell line to 1800 MHz Global System for Mobile Communication (GSM) signals in GSM-Talk mode at specific absorption rates (SAR) of 1 W/kg, 2 W/kg or 4 W/kg. Subsequently, through the use of formamidopyrimidine DNA glycosylase (FPG) in a modified comet assay, we determined that the extent of DNA migration was significantly increased at a SAR of 4 W/kg. Flow cytometry analysis demonstrated that levels of the DNA adduct 8-oxoguanine (8-oxoG) were also increased at a SAR of 4 W/kg. These increases were concomitant with similar increases in the generation of reactive oxygen species (ROS); these phenomena were mitigated by co-treatment with the antioxidant α-tocopherol. However, no detectable DNA strand breakage was observed by the alkaline comet assay. Taking together, these findings may imply the novel possibility that RF-EMR with insufficient energy for the direct induction of DNA strand breaks may produce genotoxicity through oxidative DNA base damage in male germ cells. Crown Copyright © 2013. Published by Elsevier Ireland Ltd. All rights reserved.

Hydro-ball in-core instrumentation system and method of operation

DOEpatents

Tower, Stephen N.; Veronesi, Luciano; Braun, Howard E.

1990-01-01

A hydro-ball in-core instrumentation system employs detector strings each comprising a wire having radiation sensitive balls affixed diametrically at spaced positions therealong and opposite tip ends of which are transportable by fluid drag through interior passageways. In the passageways primary coolant is caused to flow selectively in first and second opposite directions for transporting the detector strings from stored positions in an exterior chamber to inserted positions within the instrumentation thimbles of the fuel rod assemblies of a pressure vessel, and for return. The coolant pressure within the detector passageways is the same as that within the vessel; face contact, disconnectable joints between sections of the interior passageways within the vessel facilitate assembly and disassembly of the vessel for refueling and routine maintenance operations. The detector strings may pass through a very short bend radius thereby minimizing space requirements for the connections of the instrumentation system to the vessel and concomitantly the vessel containment structure. Improved radiation mapping and a significant reduction in potential exposure of personnel to radiation are provided. Both top head and bottom head penetration embodiments are disclosed.

Environmental cold exposure increases blood flow and affects pain sensitivity in the knee joints of CFA-induced arthritic mice in a TRPA1-dependent manner.

PubMed

Fernandes, Elizabeth S; Russell, Fiona A; Alawi, Khadija M; Sand, Claire; Liang, Lihuan; Salamon, Robin; Bodkin, Jennifer V; Aubdool, Aisah A; Arno, Matthew; Gentry, Clive; Smillie, Sarah-Jane; Bevan, Stuart; Keeble, Julie E; Malcangio, Marzia; Brain, Susan D

2016-01-11

The effect of cold temperature on arthritis symptoms is unclear. The aim of this study was to investigate how environmental cold affects pain and blood flow in mono-arthritic mice, and examine a role for transient receptor potential ankyrin 1 (TRPA1), a ligand-gated cation channel that can act as a cold sensor. Mono-arthritis was induced by unilateral intra-articular injection of complete Freund's adjuvant (CFA) in CD1 mice, and in mice either lacking TRPA1 (TRPA1 KO) or respective wildtypes (WT). Two weeks later, nociception and joint blood flow were measured following exposure to 10 °C (1 h) or room temperature (RT). Primary mechanical hyperalgesia in the knee was measured by pressure application apparatus; secondary mechanical hyperalgesia by automated von Frey system; thermal hyperalgesia by Hargreaves technique, and weight bearing by the incapacitance test. Joint blood flow was recorded by full-field laser perfusion imager (FLPI) and using clearance of (99m)Technetium. Blood flow was assessed after pretreatment with antagonists of either TRPA1 (HC-030031), substance P neurokinin 1 (NK1) receptors (SR140333) or calcitonin gene-related peptide (CGRP) (CGRP8-37). TRPA1, TAC-1 and CGRP mRNA levels were examined in dorsal root ganglia, synovial membrane and patellar cartilage samples. Cold exposure caused bilateral primary mechanical hyperalgesia 2 weeks after CFA injection, in a TRPA1-dependent manner. In animals maintained at RT, clearance techniques and FLPI showed that CFA-treated joints exhibited lower blood flow than saline-treated joints. In cold-exposed animals, this reduction in blood flow disappears, and increased blood flow in the CFA-treated joint is observed using FLPI. Cold-induced increased blood flow in CFA-treated joints was blocked by HC-030031 and not observed in TRPA1 KOs. Cold exposure increased TRPA1 mRNA levels in patellar cartilage, whilst reducing it in synovial membranes from CFA-treated joints. We provide evidence that environmental cold exposure enhances pain and increases blood flow in a mono-arthritis model. These changes are dependent on TRPA1. Thus, TRPA1 may act locally within the joint to influence blood flow via sensory nerves, in addition to its established nociceptive actions.

Vertical counterflow evaporative cooler

DOEpatents

Bourne, Richard C.; Lee, Brian Eric; Callaway, Duncan

2005-01-25

An evaporative heat exchanger having parallel plates that define alternating dry and wet passages. A water reservoir is located below the plates and is connected to a water distribution system. Water from the water distribution system flows through the wet passages and wets the surfaces of the plates that form the wet passages. Air flows through the dry passages, mixes with air below the plates, and flows into the wet passages before exiting through the top of the wet passages.

The Advantages of Non-Flow-Through Fuel Cell Power Systems for Aerospace Applications

NASA Technical Reports Server (NTRS)

Hoberecht, Mark; Burke, Kenneth; Jakupca, Ian

2011-01-01

NASA has been developing proton-exchange-membrane (PEM) fuel cell power systems for the past decade, as an upgraded technology to the alkaline fuel cells which presently provide power for the Shuttle Orbiter. All fuel cell power systems consist of one or more fuel cell stacks in combination with appropriate balance-of-plant hardware. Traditional PEM fuel cells are characterized as flow-through, in which recirculating reactant streams remove product water from the fuel cell stack. NASA recently embarked on the development of non-flow-through fuel cell systems, in which reactants are dead-ended into the fuel cell stack and product water is removed by internal wicks. This simplifies the fuel cell power system by eliminating the need for pumps to provide reactant circulation, and mechanical water separators to remove the product water from the recirculating reactant streams. By eliminating these mechanical components, the resulting fuel cell power system has lower mass, volume, and parasitic power requirements, along with higher reliability and longer life. These improved non-flow-through fuel cell power systems therefore offer significant advantages for many aerospace applications.

Reduced-Noise Gas Flow Design Guide Developed as a Noise-Control Design Tool for Meeting Glenn's Hearing Conservation and Community Noise Goals

NASA Technical Reports Server (NTRS)

Cooper, Beth A.

2000-01-01

A Reduced-Noise Gas Flow Design Guide has been developed for the NASA Glenn Research Center at Lewis Field by Nelson Acoustical Engineering of Elgin, Texas. Gas flow systems are a significant contributor to t he noise exposure landscape at Glenn. Because of the power of many of these systems, hearing conservation and community noise are importan t issues. The purpose of the Guide is to allow Glenn engineers and de signers to address noise emission and control at the design stage by using readily available system parameters. Although the Guide was deve loped with Glenn equipment and systems in mind, it is expected to hav e wide application in industry.

Gas Flow Detection System

NASA Technical Reports Server (NTRS)

Moss, Thomas; Ihlefeld, Curtis; Slack, Barry

2010-01-01

This system provides a portable means to detect gas flow through a thin-walled tube without breaking into the tubing system. The flow detection system was specifically designed to detect flow through two parallel branches of a manifold with only one inlet and outlet, and is a means for verifying a space shuttle program requirement that saves time and reduces the risk of flight hardware damage compared to the current means of requirement verification. The prototype Purge Vent and Drain Window Cavity Conditioning System (PVD WCCS) Flow Detection System consists of a heater and a temperature-sensing thermistor attached to a piece of Velcro to be attached to each branch of a WCCS manifold for the duration of the requirement verification test. The heaters and thermistors are connected to a shielded cable and then to an electronics enclosure, which contains the power supplies, relays, and circuit board to provide power, signal conditioning, and control. The electronics enclosure is then connected to a commercial data acquisition box to provide analog to digital conversion as well as digital control. This data acquisition box is then connected to a commercial laptop running a custom application created using National Instruments LabVIEW. The operation of the PVD WCCS Flow Detection System consists of first attaching a heater/thermistor assembly to each of the two branches of one manifold while there is no flow through the manifold. Next, the software application running on the laptop is used to turn on the heaters and to monitor the manifold branch temperatures. When the system has reached thermal equilibrium, the software application s graphical user interface (GUI) will indicate that the branch temperatures are stable. The operator can then physically open the flow control valve to initiate the test flow of gaseous nitrogen (GN2) through the manifold. Next, the software user interface will be monitored for stable temperature indications when the system is again at thermal equilibrium with the test flow of GN2. The temperature drop of each branch from its "no flow" stable temperature peak to its stable "with flow" temperature will allow the operator to determine whether a minimum level of flow exists. An alternative operation has the operator turning on the software only long enough to record the ambient temperature of the tubing before turning on the heaters and initiating GN2 flow. The stable temperature of the heated tubing with GN2 flow is then compared with the ambient tubing temperature to determine if flow is present in each branch. To help quantify the level of flow in the manifolds, each branch will be bench calibrated to establish its thermal properties using the flow detection system and different flow rates. These calibration values can then be incorporated into the software application to provide more detailed flow rate information.

Disposable and removable nucleic acid extraction and purification cartridges for automated flow-through systems

DOEpatents

Regan, John Frederick

2014-09-09

Removable cartridges are used on automated flow-through systems for the purpose of extracting and purifying genetic material from complex matrices. Different types of cartridges are paired with specific automated protocols to concentrate, extract, and purifying pathogenic or human genetic material. Their flow-through nature allows large quantities sample to be processed. Matrices may be filtered using size exclusion and/or affinity filters to concentrate the pathogen of interest. Lysed material is ultimately passed through a filter to remove the insoluble material before the soluble genetic material is delivered past a silica-like membrane that binds the genetic material, where it is washed, dried, and eluted. Cartridges are inserted into the housing areas of flow-through automated instruments, which are equipped with sensors to ensure proper placement and usage of the cartridges. Properly inserted cartridges create fluid- and air-tight seals with the flow lines of an automated instrument.

Infrasound increases intracellular calcium concentration and induces apoptosis in hippocampi of adult rats.

PubMed

Liu, Zhaohui; Gong, Li; Li, Xiaofang; Ye, Lin; Wang, Bin; Liu, Jing; Qiu, Jianyong; Jiao, Huiduo; Zhang, Wendong; Chen, Jingzao; Wang, Jiuping

2012-01-01

In the present study, we determined the effect of infrasonic exposure on apoptosis and intracellular free Ca²⁺ ([Ca²⁺]i) levels in the hippocampus of adult rats. Adult rats were randomly divided into the control and infrasound exposure groups. For infrasound treatment, animals received infrasonic exposure at 90 (8 Hz) or 130 dB (8 Hz) for 2 h per day. Hippocampi were dissected, and isolated hippocampal neurons were cultured. The [Ca²⁺]i levels in hippocampal neurons from adult rat brains were determined by Fluo-3/AM staining with a confocal microscope system on days 1, 7, 14, 21 and 28 following infrasonic exposure. Apoptosis was evaluated by Annexin V-FITC and propidium iodide double staining. Positive cells were sorted and analyzed by flow cytometry. Elevated [Ca²⁺]i levels were observed on days 14 and 21 after rats received daily treatment with 90 or 130 dB sound pressure level (SPL) infrasonic exposure (p<0.01 vs. control). The highest levels of [Ca²⁺]i were detected in the 130 dB SPL infrasonic exposure group. Meanwhile, apoptosis in hippocampal neurons was found to increase on day 7 following 90 dB SPL infrasound exposure, and significantly increased on day 14. Upon 130 dB infrasound treatment, apoptosis was first observed on day 14, whereas the number of apoptotic cells gradually decreased thereafter. Additionally, a marked correlation between cell apoptosis and [Ca²⁺]i levels was found on day 14 and 21 following daily treatment with 90 and 130 dB SPL, respectively. These results demonstrate that a period of infrasonic exposure induced apoptosis and upregulated [Ca²⁺]i levels in hippocampal neurons, suggesting that infrasound may cause damage to the central nervous system (CNS) through the Ca²⁺‑mediated apoptotic pathway in hippocampal neurons.

Development of a Through Tubing (Microhole) Artificial Lift System

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

Steve Bodden

2006-09-30

The goal of this project was to develop a small diameter pump system capable of being deployed through existing production tubing strings in oil/gas wells. The pump system would then pump water up an inner tubing string (likely coil tubing) and allow gas to flow in the annulus between the coil tubing and production tubing. Accomplishing this would allow wells that are currently loaded up (unable to flow at high enough rates to lift the fluid out of the wellbore) to continue to produce additional gas/oil reserves. The project was unable to complete a working test system due to unforeseen complexities in coupling the system components together in part due to the small diameter. Although several of the individual components were sourced and secured, coupling them together and getting electricity to the motor proved technically more difficult than expected. Thus, the project is no longer active due primarily to the complications realized in coupling the components and the difficulties in getting electricity to the submersible motor in a slimhole system. The other problem in finishing this project was the lack of financial resources. When the grant was first applied for it was expected that it would be awarded in early 2004. Since the grant was not actually awarded until the end of August 2004, GPS had basically run out ofmore » $$ and the principle developer (Steve Bodden) had to find a full time job which began in late July 2004. When the grant was finally awarded in late August, it was still hoped that the project could proceed as a part time development but with less financial exposure to the partners in GPS. This became very problematic as it still had many technical obstacles to overcome to get it to the stage of prototype testing.« less

EPA's Sustainable Port Communities: Anticipating Changes in Exposures and a Proposal to Facilitate Resilience through Knowledge Flows (MTS Workshop May 2017)

EPA Science Inventory

Port Communities Face Many Challenges: • Climate change – Sea Level Rise, Extreme Events: “Assets” become Vulnerabilities; Nuisance flooding; Changes in waste water and stormwater capacity; Changes in near-shore ecology and water quality • Port Exp...

Evaluation of tantalum-alloy-clad uranium mononitride fuel specimens from 7500-hour, 1040 C pumped-lithium-loop test

NASA Technical Reports Server (NTRS)

Watson, G. K.

1974-01-01

Simulated nuclear fuel element specimens, consisting of uranium mononitride (UN) fuel cylinders clad with tungsten-lined T-111, were exposed for up to 7500 hr at 1040 C (1900 F) in a pumped-lithium loop. The lithium flow velocity was 1.5 m/sec (5 ft/sec) in the specimen test section. No evidence of any compatibility problems between the specimens and the flowing lithium was found based on appearance, weight change, chemistry, and metallography. Direct exposure of the UN to the lithium through a simulated cladding crack resulted in some erosion of the UN in the area of the defect. The T-111 cladding was ductile after lithium exposure, but it was sensitive to hydrogen embrittlement during post-test handling.

Filter desulfation system and method

DOEpatents

Lowe, Michael D.; Robel, Wade J.; Verkiel, Maarten; Driscoll, James J.

2010-08-10

A method of removing sulfur from a filter system of an engine includes continuously passing an exhaust flow through a desulfation leg of the filter system during desulfation. The method also includes sensing at least one characteristic of the exhaust flow and modifying a flow rate of the exhaust flow during desulfation in response to the sensing.

In hamsters the D1 receptor antagonist SCH23390 depresses ventilation during hypoxia.

PubMed

Schlenker, Evelyn H

2008-01-02

During exposure of animals to hypoxia, brain and blood dopamine levels increase stimulating dopaminergic receptors which influence the integrated ventilatory response to low oxygen. The purpose of the present study is to test the hypothesis that in conscious hamsters, systemic antagonism of D(1) receptors would depress their breathing in air and in response to hypoxic and hypercapnic challenges. Nine male hamsters were treated with saline or 0.25 mg/kg SCH-23390 (SCH), a D(1) receptor antagonist that crosses the blood-brain barrier. Ventilation was determined using the barometric method, and oxygen consumption and CO(2) production were evaluated utilizing the flow-through method. During exposure to air, SCH decreased frequency of breathing. During exposure to hypoxia (10% oxygen in nitrogen), relative to saline, SCH-treated hamsters decreased minute ventilation by decreasing tidal volume and oxygen consumption but not CO(2) production. During exposure to hypercapnia (5% CO(2) in 95% O(2)), frequency of breathing was decreased with SCH, but there was no significant effect on minute ventilation. Relative to saline treatment body temperature was lower in SCH-treated hamsters by 0.6 degrees C. These results demonstrate that in hamsters D(1) receptors can modulate control of ventilation in air and during hypoxia and hypercapnic exposures. Whether D(1) receptors located centrally or on carotid bodies modulate these effects is not clear from this study.

Understanding possible underlying mechanism in declining germicidal efficiency of UV-LED reactor.

PubMed

Lee, Hyunkyung; Jin, Yongxun; Hong, Seungkwan

2018-06-07

Since ultraviolet light emitting diodes (UV-LEDs) have emerged as an alternative light source for UV disinfection systems, enhancement of reactor performance is a demanding challenge to promote its practical application in water treatment process. This study explored the underlying mechanism of the inefficiency observed in flow-through mode UV disinfection tests to improve the light utilization of UV-LED applications. In particular, the disinfection performance of UV-LED reactors was evaluated using two different flow channel types, reservoir and pathway systems, in order to elucidate the impact of physical circumstances on germicidal efficiency as the light profile was adjusted. Overall, a significant reduction in germicidal efficiency was observed when exposure time was prolonged or a mixing chamber was integrated. Zeta analysis revealed that the repulsion rate between microorganisms decreased with UV fluence transfer, and that change might cause the shielding effect of UV delivery to target microorganisms. In line with the above findings, the reduction in efficiency intensified when opportunities for microbial collision increased. Thus, UV induced microbial aggregation was implicated as being a disinfection hindering factor, exerting its effect through uneven UV illumination. Ultimately, the results refuted the prevailing belief that UV has a cumulative effect. We found that the reservoir system achieved worse performance than the pathway system despite it providing 15 times higher UV fluence: the differences in germicidal efficiency were 1-log, 1.4-log and 1.7-log in the cases of P.aeruginosa, E.coli and S.aureus, respectively. Copyright © 2018 Elsevier B.V. All rights reserved.

A bioaccumulation bioassay for freshwater sediments

USGS Publications Warehouse

Mac, Michael J.; Noguchi, George E.; Hesselberg, Robert J.; Edsall, Carol C.; Shoesmith, John A.; Bowker, James D.

1990-01-01

A laboratory bioassay is described for determining the bioavailability of contaminants from freshwater sediments. The bioassay consists of 10-d exposures to whole sediments under flow-through conditions. After testing five species, the fathead minnow (Pimephales promelas) and the earthworm (Lubricus terrestris) were recommended for use in the test. When the availability of polychlorinated biphenyls (PCBs), Hg and Zn from Great Lakes sediments was examined in laboratory exposures, only the PCBs were accumulated. A field validation study demonstrated that the magnitude of accumulation in laboratory exposures was similar to that in organisms caged in the field. A protocol is recommended for using the test as a standardized bioaccumulation bioassay.

Assessing workplace chemical exposures: the role of exposure monitoring.

PubMed

Harper, Martin

2004-05-01

Occupational exposure is the condition of being subjected through employment to a chemical, physical, or biological agent, or to a specific process, practice, behavior, or organization of work. Exposure to a chemical agent is typically the contact of that agent with the outer boundary of a subject, such as the respiratory system, skin, or digestive system. In occupational hygiene we are most concerned with exposure through the respiratory system, although, increasingly we are concerned with the results of dermal exposures, including those exposures to the skin that can be transferred to the mouth and digestive system. This presentation will detail methods available for assessing personal exposures to chemicals through monitoring. The results from monitoring can then be compared to established guidelines and regulations, although this is not the only rationale for making measurements. These monitoring methods are currently used around the world to establish the benchmark hazard from which risk to the worker can be predicted. The presentation will describe the general techniques for assessing exposures to the respiratory system from chemical gases and vapors, chemical dusts, and exposures to the skin from bulk chemicals or chemical contamination of surfaces. For respiratory exposures, direct-reading instruments are available for spot measurements, and for monitoring short-term fluctuations in concentration. However, most standards and regulations are based on time-integrated (time-weighted average) exposures, requiring longer-term integrative methods. Therefore, the specific focus of this review will be the methods available for full work-shift sampling. For gases and vapors this will include taking whole-air samples in canisters or polymer bags, or concentration of chemicals by absorption in liquids or adsorption on solid sorbents, with subsequent chemical analysis. Chemical concentration can take place by pumping air through the sorbing media, or by allowing molecules to diffuse to the sorbent surface. Transfer of the collected chemicals to the analytical instrumentation can be accomplished using solvent displacement and injection, or through the application of heat to bring the collected molecules back into the vapor phase. For particles, the particle size is important as this determines the site of deposition in the lungs, and so time-integrated sampling on filters using various types of size-selective samplers is preferred. Finally, some techniques that have been used to assess the potential for chemical contamination of the skin are presented. Biomonitoring is another tool that can be used to assess exposure, and the results are more relevant to dosimetric considerations than exposure. Biomonitoring is a complex subject worthy of a separate review, and will be considered only briefly here.

Computation of Flow Through Water-Control Structures Using Program DAMFLO.2

USGS Publications Warehouse

Sanders, Curtis L.; Feaster, Toby D.

2004-01-01

As part of its mission to collect, analyze, and store streamflow data, the U.S. Geological Survey computes flow through several dam structures throughout the country. Flows are computed using hydraulic equations that describe flow through sluice and Tainter gates, crest gates, lock gates, spillways, locks, pumps, and siphons, which are calibrated using flow measurements. The program DAMFLO.2 was written to compute, tabulate, and plot flow through dam structures using data that describe the physical properties of dams and various hydraulic parameters and ratings that use time-varying data, such as lake elevations or gate openings. The program uses electronic computer files of time-varying data, such as lake elevation or gate openings, retrieved from the U.S. Geological Survey Automated Data Processing System. Computed time-varying flow data from DAMFLO.2 are output in flat files, which can be entered into the Automated Data Processing System database. All computations are made in units of feet and seconds. DAMFLO.2 uses the procedures and language developed by the SAS Institute Inc.

Flow Cells for Scalable Energy Conversion and Storage

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

Mukundan, Rangachary

2017-10-26

This project is a response to current flow systems that are V-aqueous and not cost effective. It will hopefully enable high energy/ power density flow cells through rational materials and system design.

Bidirectional Pressure-Regulator System

NASA Technical Reports Server (NTRS)

Burke, Kenneth; Miller, John R.

2008-01-01

A bidirectional pressure-regulator system has been devised for use in a regenerative fuel cell system. The bidirectional pressure-regulator acts as a back-pressure regulator as gas flows through the bidirectional pressure-regulator in one direction. Later, the flow of gas goes through the regulator in the opposite direction and the bidirectional pressure-regulator operates as a pressure- reducing pressure regulator. In the regenerative fuel cell system, there are two such bidirectional regulators, one for the hydrogen gas and another for the oxygen gas. The flow of gases goes from the regenerative fuel cell system to the gas storage tanks when energy is being stored, and reverses direction, flowing from the storage tanks to the regenerative fuel cell system when the stored energy is being withdrawn from the regenerative fuel cell system. Having a single bidirectional regulator replaces two unidirectional regulators, plumbing, and multiple valves needed to reverse the flow direction. The term "bidirectional" refers to both the bidirectional nature of the gas flows and capability of each pressure regulator to control the pressure on either its upstream or downstream side, regardless of the direction of flow.

A Comparison of Flow-Through Versus Non-Flow-Through Proton Exchange Membrane Fuel Cell Systems for NASA's Exploration Missions

NASA Technical Reports Server (NTRS)

Hoberecht, Mark A.

2010-01-01

As part of the Exploration Technology Development Program (ETDP) under the auspices of the Exploration Systems Mission Directorate (ESMD), NASA is developing both primary fuel cell power systems and regenerative fuel cell (RFC) energy storage systems within the fuel cell portion of the Energy Storage Project. This effort is being led by the NASA Glenn Research Center (GRC) in partnership with the NASA Johnson Space Center (JSC), Jet Propulsion Laboratory (JPL), NASA Kennedy Space Center (KSC), and industrial partners. The development goals are to improve fuel cell and electrolysis stack electrical performance, reduce system mass, volume, and parasitic power requirements, and increase system life and reliability. A major focus of this effort has been the parallel development of both flow-through and non-flow-through proton exchange membrane (PEM) primary fuel cell power systems. The plan has been, at the appropriate time, to select a single primary fuel cell technology for eventual flight hardware development. Ideally, that appropriate time would occur after both technologies have achieved a technology readiness level (TRL) of six, which represents an engineering model fidelity PEM fuel cell system being successfully tested in a relevant environment. Budget constraints in fiscal year 2009 and beyond have prevented NASA from continuing to pursue the parallel development of both primary fuel cell options. Because very limited data exists for either system, a toplevel, qualitative assessment based on engineering judgement was performed expeditiously to provide guidance for a selection. At that time, the non-flow-through technology was selected for continued development because of potentially major advantages in terms of weight, volume, parasitic power, reliability, and life. This author believes that the advantages are significant enough, and the potential benefits great enough, to offset the higher state of technology readiness of flow-through technology. This paper summarizes the technical considerations which helped form the engineering judgement that led to the final decision.

Estimating Preferential Flow in Karstic Aquifers Using Statistical Mixed Models

PubMed Central

Anaya, Angel A.; Padilla, Ingrid; Macchiavelli, Raul; Vesper, Dorothy J.; Meeker, John D.; Alshawabkeh, Akram N.

2013-01-01

Karst aquifers are highly productive groundwater systems often associated with conduit flow. These systems can be highly vulnerable to contamination, resulting in a high potential for contaminant exposure to humans and ecosystems. This work develops statistical models to spatially characterize flow and transport patterns in karstified limestone and determines the effect of aquifer flow rates on these patterns. A laboratory-scale Geo-HydroBed model is used to simulate flow and transport processes in a karstic limestone unit. The model consists of stainless-steel tanks containing a karstified limestone block collected from a karst aquifer formation in northern Puerto Rico. Experimental work involves making a series of flow and tracer injections, while monitoring hydraulic and tracer response spatially and temporally. Statistical mixed models are applied to hydraulic data to determine likely pathways of preferential flow in the limestone units. The models indicate a highly heterogeneous system with dominant, flow-dependent preferential flow regions. Results indicate that regions of preferential flow tend to expand at higher groundwater flow rates, suggesting a greater volume of the system being flushed by flowing water at higher rates. Spatial and temporal distribution of tracer concentrations indicates the presence of conduit-like and diffuse flow transport in the system, supporting the notion of both combined transport mechanisms in the limestone unit. The temporal response of tracer concentrations at different locations in the model coincide with, and confirms the preferential flow distribution generated with the statistical mixed models used in the study. PMID:23802921

Estimating preferential flow in karstic aquifers using statistical mixed models.

PubMed

Anaya, Angel A; Padilla, Ingrid; Macchiavelli, Raul; Vesper, Dorothy J; Meeker, John D; Alshawabkeh, Akram N

2014-01-01

Karst aquifers are highly productive groundwater systems often associated with conduit flow. These systems can be highly vulnerable to contamination, resulting in a high potential for contaminant exposure to humans and ecosystems. This work develops statistical models to spatially characterize flow and transport patterns in karstified limestone and determines the effect of aquifer flow rates on these patterns. A laboratory-scale Geo-HydroBed model is used to simulate flow and transport processes in a karstic limestone unit. The model consists of stainless steel tanks containing a karstified limestone block collected from a karst aquifer formation in northern Puerto Rico. Experimental work involves making a series of flow and tracer injections, while monitoring hydraulic and tracer response spatially and temporally. Statistical mixed models (SMMs) are applied to hydraulic data to determine likely pathways of preferential flow in the limestone units. The models indicate a highly heterogeneous system with dominant, flow-dependent preferential flow regions. Results indicate that regions of preferential flow tend to expand at higher groundwater flow rates, suggesting a greater volume of the system being flushed by flowing water at higher rates. Spatial and temporal distribution of tracer concentrations indicates the presence of conduit-like and diffuse flow transport in the system, supporting the notion of both combined transport mechanisms in the limestone unit. The temporal response of tracer concentrations at different locations in the model coincide with, and confirms the preferential flow distribution generated with the SMMs used in the study. © 2013, National Ground Water Association.

Exposure effects of levonorgestrel on oogenesis in the fathead minnow (Pimephales promelas).

PubMed

Frankel, Tyler; Yonkos, Lance; Frankel, Jack

2017-12-01

The synthetic progestin levonorgestrel is commonly utilized in human oral contraceptives. It enters the environment as a component of wastewater treatment plant effluent, and has been measured at low ng/L concentrations in surface waters. It has been shown to activate fish androgen receptors, causing the physical masculinization of females, changes in reproductive behavior, and decreases in fecundity. In the present study, the effects of levonorgestrel exposure on early-stage oogenesis in the fathead minnow (Pimephales promelas) was examined. Adult females were exposed to 0, 10, or 100 ng/L levonorgestrel for 14 d using a flow-through exposure system. The ovaries from each female were then removed via dissection and weighed for gonadosomatic index (GSI) calculations, and oocytes from one lobe preserved in Serra's fixative. Total numbers of late-stage vitellogenic oocytes exhibiting a germinal vesicle were then quantified. In a second exposure, blood plasma samples were collected from adult females and analyzed for vitellogenin concentrations using enzyme-linked immunosorbent assay. Females exposed to both concentrations of levonorgestrel developed male secondary sexual characteristics in a dose-dependent manner, and ovaries contained significantly fewer late stage oocytes. Exposure to 100 ng/L of levonorgestrel resulted in decreased GSI and blood plasma vitellogenin concentrations. The results suggest that female exposure to levonorgestrel alone may have profound effects on reproduction in progestin-contaminated environments. Environ Toxicol Chem 2017;36:3299-3304. © 2017 SETAC. © 2017 SETAC.

Bioconcentration and effects of hexabromocyclododecane exposure in crucian carp (Carassius auratus).

PubMed

Dong, Huike; Lu, Guanghua; Yan, Zhenhua; Liu, Jianchao; Yang, Haohan; Nkoom, Matthew

2018-04-01

As a cycloaliphatic brominated flame retardant, hexabromocyclododecane (HBCD) has been widely used in building thermal insulation and fireproof materials. However, there is little information on the bioconcentration as well as effects with respect to HBCD exposure in the aquatic environment. To investigate the bioconcentration of HBCD in tissues (muscle and liver) and its biochemical and behavioural effects, juvenile crucian carp (Carassius auratus) were exposed to different concentrations of technical HBCD (nominal concentrations, 2, 20, 200 μg/L) for 7 days, using a flow-through exposure system. HBCD was found to concentrate in the liver and muscle with a terminal concentration of 0.60 ± 0.22 μg/g lw (lipid weight) and 0.18 ± 0.02 μg/g lw, respectively, at an environmentally-relevant concentration (2 μg/L). The total thyroxine and total triiodothyronine in the fish plasma were lowered as a result of exposure to the HBCD. Acetylcholinesterase activity in the brain was increased, while swimming activity was inhibited and shoaling inclination was enhanced after exposure to 200 μg/L HBCD. Feeding rate was suppressed in the 20 and 200 μg/L treatment groups. In summary, HBCD concentrations 10-100× higher than the current environmentally-relevant exposures induced adverse effects in the fish species tested in this study. These results suggest that increasing environmental concentrations and/or species with higher sensitivity than carp might be adversely affected by HBCD.

Effect of childhood malnutrition on salivary flow and pH.

PubMed

Psoter, Walter J; Spielman, Andrew L; Gebrian, Bette; St Jean, Rudolph; Katz, Ralph V

2008-03-01

While protein-energy malnutrition may have multiple effects on oral tissues and subsequent disease development, reports of the effect of malnutrition on the human salivary glands are sparse. A retrospective cohort study of the effect of early childhood protein-energy malnutrition (EC-PEM) and adolescent nutritional status on salivary flow and pH was conducted with rural Haitian children, ages 11-19 years (n=1017). Malnutrition strata exposure cohorts were based on 1988-1996 weight-for-age records which covered the birth through 5-year-old period for all subjects. Then, data on current anthropometrical defined nutritional status categories, stimulated and unstimulated salivary flow rates, and salivary pH were collected for the same subjects of 11-19 years old during field examinations in the summer of 2005. Multivariate analysis of variance (MANOVA) was used for the analyses. Stimulated and unstimulated salivary flow rates were reduced at statistically significant levels in subjects who had experienced severe malnutrition in their early childhood or who had continuing nutrition stress which resulted in delayed growth, as measured at ages 11-19 years. Salivary pH demonstrated little clinically meaningful variability between malnourished and nonmalnourished groups. This study is the first to report of a continuing effect on diminished salivary gland function into adolescence as a result of early childhood malnutrition (EC-PEM) and suggests that exocrine glandular systems may be compromised for extended periods following EC-PEM, which may have important implications for the body's systemic antimicrobial defences.

Characterization of TCE DNAPL and Dissolved Phase Transport in Karst Media

NASA Astrophysics Data System (ADS)

Carmona, M.; Padilla, I. Y.

2015-12-01

Trichloroethylene (TCE) contaminated sites are a threat to the environment and human health. Of particular concerns is the contamination of karst groundwater systems (KGWSs). Their heterogeneous character, rapid flow through conduits, high permeability zones, and strong storage capacity in the rock porous-matrix pose a high risk of exposure over large areas and temporal scales. To achieve effective remedial actions for TCE removal, it is important to understand and quantify the fate and transport process of trichloroethylene in these systems. This research studies the fate, transport, and distribution of TCE Non-Aqueous Phase Liquids (NAPLs) and associated dissolved species in KGWSs. Experiments are conducted in a karstified limestone physical model, a limestone rock mimicking a saturated confined karst aquifer. After injecting TCE solvent into a steady groundwater flow field, samples are taken spatially and temporally and analyzed for TCE NAPL and dissolved phases. Data analysis shows the rapid detection of TCE NAPL and high aqueous concentrations along preferential pathway, even at distances far away from the injection point. Temporal distribution curves exhibit spatial variations related to the limestone rock heterogeneity. Rapid response to TCE concentrations is associated with preferential flow paths. Slow response with long tailing indicates rate-limited diffusive transport in the rock matrix. Overall, results indicate that karstified limestone has a high capacity to rapidly transport pure and dissolved TCE along preferential flow paths, and to store and slowly release TCE over long periods of time.

Effectiveness of in-room air filtration and dilution ventilation for tuberculosis infection control.

PubMed

Miller-Leiden, S; Lobascio, C; Nazaroff, W W; Macher, J M

1996-09-01

Tuberculosis (TB) is a public health problem that may pose substantial risks to health care workers and others. TB infection occurs by inhalation of airborne bacteria emitted by persons with active disease. We experimentally evaluated the effectiveness of in-room air filtration systems, specifically portable air filters (PAFs) and ceiling-mounted air filters (CMAFs), in conjunction with dilution ventilation, for controlling TB exposure in high-risk settings. For each experiment, a test aerosol was continuously generated and released into a full-sized room. With the in-room air filter and room ventilation system operating, time-averaged airborne particle concentrations were measured at several points. The effectiveness of in-room air filtration plus ventilation was determined by comparing particle concentrations with and without device operation. The four PAFs and three CMAFs we evaluated reduced room-average particle concentrations, typically by 30% to 90%, relative to a baseline scenario with two air-changes per hour of ventilation (outside air) only. Increasing the rate of air flow recirculating through the filter and/or air flow from the ventilation did not always increase effectiveness. Concentrations were generally higher near the emission source than elsewhere in the room. Both the air flow configuration of the filter and its placement within the room were important, influencing room air flow patterns and the spatial distribution of concentrations. Air filters containing efficient, but non-high efficiency particulate air (HEPA) filter media were as effective as air filters containing HEPA filter media.

Effectiveness of In-Room Air Filtration and Dilution Ventilation for Tuberculosis Infection Control.

PubMed

Miller-Leiden, S; Lohascio, C; Nazaroff, W W; Macher, J M

1996-09-01

Tuberculosis (TB) is a public health problem that may pose substantial risks to health care workers and others. TB infection occurs by inhalation of airborne bacteria emitted by persons with active disease. We experimentally evaluated the effectiveness of in-room air filtration systems, specifically portable air filters (PAFs) and ceiling-mounted air filters (CMAFs), in conjunction with dilution ventilation, for controlling TB exposure in high-risk settings. For each experiment, a test aerosol was continuously generated and released into a full-sized room. With the in-room air filter and room ventilation system operating, time-averaged airborne particle concentrations were measured at several points. The effectiveness of in-room air filtration plus ventilation was determined by comparing particle concentrations with and without device operation. The four PAFs and three CMAFs we evaluated reduced room-average particle concentrations, typically by 30% to 90%, relative to a baseline scenario with two air-changes per hour of ventilation (outside air) only. Increasing the rate of air flow recirculating through the filter and/or air flow from the ventilation did not always increase effectiveness. Concentrations were generally higher near the emission source than elsewhere in the room. Both the air flow configuration of the filter and its placement within the room were important, influencing room air flow patterns and the spatial distribution of concentrations. Air filters containing efficient, but non-high efficiency particulate air (HEPA) filter media were as effective as air filters containing HEPA filter media.

Improving the ablation efficiency of excimer laser systems with higher repetition rates through enhanced debris removal and optimized spot pattern.

PubMed

Arba-Mosquera, Samuel; Klinner, Thomas

2014-03-01

To evaluate the reasons for the required increased radiant exposure for higher-repetition-rate excimer lasers and determine experimentally possible compensations to achieve equivalent ablation profiles maintaining the same single-pulse energies and radiant exposures for laser repetition rates ranging from 430 to 1000 Hz. Schwind eye-tech-solutions GmbH and Co. KG, Kleinostheim, Germany. Experimental study. Poly(methyl methacrylate) (PMMA) plates were photoablated. The pulse laser energy was maintained during all experiments; the effects of the flow of the debris removal, the shot pattern for the correction, and precooling the PMMA plates were evaluated in terms of achieved ablation versus repetition rate. The mean ablation performance ranged from 88% to 100%; the variability between the profile measurements ranged from 1.4% to 6.2%. Increasing the laser repetition rate from 430 Hz to 1000 Hz reduced the mean ablation performance from 98% to 91% and worsened the variability from 1.9% to 4.3%. Increasing the flow of the debris removal, precooling the PMMA plates to -18°C, and adapting the shot pattern for the thermal response of PMMA to excimer ablation helped stabilize the variability. Only adapting the shot pattern for the thermal response of PMMA to excimer ablation helped stabilize the mean ablation performance. The ablation performance of higher-repetition-rate excimer lasers on PMMA improved with improvements in the debris removal systems and shot pattern. More powerful debris removal systems and smart shot patterns in terms of thermal response improved the performance of these excimer lasers. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Nonintrusive Flow Rate Determination Through Space Shuttle Water Coolant Loop Floodlight Coldplate

NASA Technical Reports Server (NTRS)

Werlink, Rudolph; Johnson, Harry; Margasahayam, Ravi

1997-01-01

Using a Nonintrusive Flow Measurement System (NFMS), the flow rates through the Space Shuttle water coolant coldplate were determined. The objective of this in situ flow measurement was to prove or disprove a potential block inside the affected coldplate had contributed to a reduced flow rate and the subsequent ice formation on the Space Shuttle Discovery. Flow through the coldplate was originally calculated to be 35 to 38 pounds per hour. This application of ultrasonic technology advanced the envelope of flow measurements through use of 1/4-inch-diameter tubing, which resulted in extremely low flow velocities (5 to 30 pounds per hour). In situ measurements on the orbiters Discovery and Atlantis indicated both vehicles, on the average, experienced similar flow rates through the coldplate (around 25 pounds per hour), but lower rates than the designed flow. Based on the noninvasive checks, further invasive troubleshooting was eliminated. Permanent monitoring using the NFMS was recommended.

Validation of an in vitro exposure system for toxicity assessment of air-delivered nanomaterials

PubMed Central

Kim, Jong Sung; Peters, Thomas M.; O’Shaughnessy, Patrick T.; Adamcakova-Dodd, Andrea; Thorne, Peter S.

2013-01-01

To overcome the limitations of in vitro exposure of submerged lung cells to nanoparticles (NPs), we validated an integrated low flow system capable of generating and depositing airborne NPs directly onto cells at an air–liquid interface (ALI). The in vitro exposure system was shown to provide uniform and controlled dosing of particles with 70.3% efficiency to epithelial cells grown on transwells. This system delivered a continuous airborne exposure of NPs to lung cells without loss of cell viability in repeated 4 h exposure periods. We sequentially exposed cells to air-delivered copper (Cu) NPs in vitro to compare toxicity results to our prior in vivo inhalation studies. The evaluation of cellular dosimetry indicated that a large amount of Cu was taken up, dissolved and released into the basolateral medium (62% of total mass). Exposure to Cu NPs decreased cell viability to 73% (p < 0.01) and significantly (p < 0.05) elevated levels of lactate dehydrogenase, intracellular reactive oxygen species and interleukin-8 that mirrored our findings from subacute in vivo inhalation studies in mice. Our results show that this exposure system is useful for screening of NP toxicity in a manner that represents cellular responses of the pulmonary epithelium in vivo. PMID:22981796

Microchannel array flow analyzer for measurement of whole blood rheology and flow characteristics of leukocytes activated by bacterial stimulation

NASA Astrophysics Data System (ADS)

Kikuchi, Yuji; Fujieda, Sadao; Kikuchi, Hiroko E.

1997-03-01

Microgrooves (width 6, 7, and 8 micrometer, each with length 20, 30, and 40 micrometers, respectively; depth 4.5 micrometers; number 4704 in parallel of one size per chip; chip dimensions 12 multiplied by 12 mm) photofabricated in the surface of a single-crystal silicon substrate were converted to leak-proof microchannels by tightly covering them with an optically flat glass plate. Using the microchannels as a model of physiological capillaries, total flow rate of heparinized whole blood taken from healthy subjects was determined under a constant suction of 20 cmH2O, while flow behavior of blood cells through individual channels was microscopically observed. The apparent viscosity (ratio to that of saline) of whole blood was obtained as 4.7 plus or minus 0.5, 3.7 plus or minus 0.3, and 3.4 plus or minus 0.2 (mean plus or minus SD, n equals 4) for 6, 7, and 8 micrometer width channels, respectively. Normal leukocytes passed, showing a round shape, through the channels much more slowly then erythrocytes, but caused no appreciable interference with passage of erythrocytes. Meanwhile, cells exposed to the chemotactic peptide FMLP (1 - 10 nM) and bacterial cells (Escherichia coli K 12; 6 multiplied by 106/ml) slowed further greatly, showing very irregular shapes, and eventually blocked the channels. Such a response of leukocytes took place immediately after the exposure to FMLP, but it appeared gradually with time after the exposure to the cells.

Development of a multi-exposure speckle imaging for mice brain imaging

NASA Astrophysics Data System (ADS)

Soleimanzad, Haleh; Gurden, Hirac; Pain, Frédéric

2017-02-01

In the last decade, Laser Speckle Contrast Imaging (LSCI) has been proposed and validated for imaging cerebral blood flow at the rodent brain surface in vivo. The technique relies on the calculation of the spatial speckle contrast, which is related to the velocity of scatterers (red blood cells). The implementation of the technique requires a partial craniotomy so that the brain tissues of interest can be illuminated with a laser diode. However, the studies of changes in the microcirculation during disease progression or treatment require longitudinal studies (i.e. imaging is done repeatedly over weeks or even months). Practically, the less invasive way to obtain such data is to image through the thinned skull without a craniotomy. However the presence of static scatterers (skull) will affect the speckle calculation and produce a bias in the estimation of the microcirculation changes. An extension to LSCI, termed Multi-Exposure Speckle Imaging (MESI) was proposed and validated a few years ago that address these limitations. It relies on a model of the speckle contrast as a function of the exposure time and the proportion of static scatterers. Here, we used MESI with the aim of repeatedly imaging the olfactory bulb of mice models of obesity. First, we have developed a MESI set up which was characterized on microfluidic flow phantoms with different flow-rates and channel diameters to simulate blood flow in animal model characteristics. Second, we show that MESI can discriminate flows in the presence of static scatterers and it can measure flow changes consistently. Finally we provide an in vivo validation of the technique in mice with and without a craniotomy.

Sources of metal loads to the Alamosa River and estimation of seasonal and annual metal loads for the Alamosa River basin, Colorado, 1995-97

USGS Publications Warehouse

Ortiz, Roderick F.; Edelmann, Patrick; Ferguson, Sheryl; Stogner, Robert

2002-01-01

Metal contamination in the upper Alamosa River Basin has occurred for decades from the Summitville Mine site, from other smaller mines, and from natural, metal-enriched acidic drainage in the basin. In 1995, the need to quantify contamination from various source areas in the basin and to quantify the spatial, seasonal, and annual metal loads in the basin was identified. Data collection occurred from 1995 through 1997 at numerous sites to address data gaps. Metal loads were calculated and the percentages of metal load contributions from tributaries to three risk exposure areas were determined. Additionally, a modified time-interval method was used to estimate seasonal and annual metal loads in the Alamosa River and Wightman Fork. Sources of dissolved and total-recoverable aluminum, copper, iron, and zinc loads were determined for Exposure Areas 3a, 3b, and 3c. Alum Creek is the predominant contributor of aluminum, copper, iron, and zinc loads to Exposure Area 3a. In general, Wightman Fork was the predominant source of metals to Exposure Area 3b, particularly during the snowmelt and summer-flow periods. During the base-flow period, however, aluminum and iron loads from Exposure Area 3a were the dominant source of these metals to Exposure Area 3b. Jasper and Burnt Creeks generally contributed less than 10 percent of the metal loads to Exposure Area 3b. On a few occasions, however, Jasper and Burnt Creeks contributed a substantial percentage of the loads to the Alamosa River. The metal loads calculated for Exposure Area 3c result from upstream sources; the primary upstream sources are Wightman Fork, Alum Creek, and Iron Creek. Tributaries in Exposure Area 3c did not contribute substantially to the metal load in the Alamosa River. In many instances, the percentage of dissolved and/or total-recoverable metal load contribution from a tributary or the combined percentage of metal load contribution was greater than 100 percent of the metal load at the nearest downstream site on the Alamosa River. These data indicate that metal partitioning and metal deposition from the water column to the streambed may be occurring in Exposure Areas 3a, 3b, and 3c. Metals that are deposited to the streambed probably are resuspended and transported downstream during high streamflow periods such as during snowmelt runoff and rainfall runoff. Seasonal and annual dissolved and totalrecoverable aluminum, copper, iron, and zinc loads> for 1995?97 were estimated for Exposure Areas 1, 2, 3a, 3b, and 3c. During 1995?97, many tons of metals were transported annually through each exposure area. Generally, the largest estimated annual totalrecoverable metal mass for most metals was in 1995. The smallest estimated annual total-recoverable metal mass was in 1996, which also had the smallest annual streamflow. In 1995 and 1997, more than 60 percent of the annual total-recoverable metal loads generally was transported through each exposure area during the snowmelt period. A comparison of the estimated storm load at each site to the corresponding annual load indicated that storms contribute less than 2 percent of the annual load at any site and about 5 to 20 percent of the load during the summer-flow period.

Integrating Address Geocoding, Land Use Regression, and Spatiotemporal Geostatistical Estimation for Groundwater Tetrachloroethylene

PubMed Central

Messier, Kyle P.; Akita, Yasuyuki; Serre, Marc L.

2012-01-01

Geographic Information Systems (GIS) based techniques are cost-effective and efficient methods used by state agencies and epidemiology researchers for estimating concentration and exposure. However, budget limitations have made statewide assessments of contamination difficult, especially in groundwater media. Many studies have implemented address geocoding, land use regression, and geostatistics independently, but this is the first to examine the benefits of integrating these GIS techniques to address the need of statewide exposure assessments. A novel framework for concentration exposure is introduced that integrates address geocoding, land use regression (LUR), below detect data modeling, and Bayesian Maximum Entropy (BME). A LUR model was developed for Tetrachloroethylene that accounts for point sources and flow direction. We then integrate the LUR model into the BME method as a mean trend while also modeling below detects data as a truncated Gaussian probability distribution function. We increase available PCE data 4.7 times from previously available databases through multistage geocoding. The LUR model shows significant influence of dry cleaners at short ranges. The integration of the LUR model as mean trend in BME results in a 7.5% decrease in cross validation mean square error compared to BME with a constant mean trend. PMID:22264162

Integrating address geocoding, land use regression, and spatiotemporal geostatistical estimation for groundwater tetrachloroethylene.

PubMed

Messier, Kyle P; Akita, Yasuyuki; Serre, Marc L

2012-03-06

Geographic information systems (GIS) based techniques are cost-effective and efficient methods used by state agencies and epidemiology researchers for estimating concentration and exposure. However, budget limitations have made statewide assessments of contamination difficult, especially in groundwater media. Many studies have implemented address geocoding, land use regression, and geostatistics independently, but this is the first to examine the benefits of integrating these GIS techniques to address the need of statewide exposure assessments. A novel framework for concentration exposure is introduced that integrates address geocoding, land use regression (LUR), below detect data modeling, and Bayesian Maximum Entropy (BME). A LUR model was developed for tetrachloroethylene that accounts for point sources and flow direction. We then integrate the LUR model into the BME method as a mean trend while also modeling below detects data as a truncated Gaussian probability distribution function. We increase available PCE data 4.7 times from previously available databases through multistage geocoding. The LUR model shows significant influence of dry cleaners at short ranges. The integration of the LUR model as mean trend in BME results in a 7.5% decrease in cross validation mean square error compared to BME with a constant mean trend.

Modeling Patient-Specific Magnetic Drug Targeting Within the Intracranial Vasculature

PubMed Central

Patronis, Alexander; Richardson, Robin A.; Schmieschek, Sebastian; Wylie, Brian J. N.; Nash, Rupert W.; Coveney, Peter V.

2018-01-01

Drug targeting promises to substantially enhance future therapies, for example through the focussing of chemotherapeutic drugs at the site of a tumor, thus reducing the exposure of healthy tissue to unwanted damage. Promising work on the steering of medication in the human body employs magnetic fields acting on nanoparticles made of paramagnetic materials. We develop a computational tool to aid in the optimization of the physical parameters of these particles and the magnetic configuration, estimating the fraction of particles reaching a given target site in a large patient-specific vascular system for different physiological states (heart rate, cardiac output, etc.). We demonstrate the excellent computational performance of our model by its application to the simulation of paramagnetic-nanoparticle-laden flows in a circle of Willis geometry obtained from an MRI scan. The results suggest a strong dependence of the particle density at the target site on the strength of the magnetic forcing and the velocity of the background fluid flow. PMID:29725303

Modeling Patient-Specific Magnetic Drug Targeting Within the Intracranial Vasculature.

PubMed

Patronis, Alexander; Richardson, Robin A; Schmieschek, Sebastian; Wylie, Brian J N; Nash, Rupert W; Coveney, Peter V

2018-01-01

Drug targeting promises to substantially enhance future therapies, for example through the focussing of chemotherapeutic drugs at the site of a tumor, thus reducing the exposure of healthy tissue to unwanted damage. Promising work on the steering of medication in the human body employs magnetic fields acting on nanoparticles made of paramagnetic materials. We develop a computational tool to aid in the optimization of the physical parameters of these particles and the magnetic configuration, estimating the fraction of particles reaching a given target site in a large patient-specific vascular system for different physiological states (heart rate, cardiac output, etc.). We demonstrate the excellent computational performance of our model by its application to the simulation of paramagnetic-nanoparticle-laden flows in a circle of Willis geometry obtained from an MRI scan. The results suggest a strong dependence of the particle density at the target site on the strength of the magnetic forcing and the velocity of the background fluid flow.

Automated high-throughput flow-through real-time diagnostic system

DOEpatents

Regan, John Frederick

2012-10-30

An automated real-time flow-through system capable of processing multiple samples in an asynchronous, simultaneous, and parallel fashion for nucleic acid extraction and purification, followed by assay assembly, genetic amplification, multiplex detection, analysis, and decontamination. The system is able to hold and access an unlimited number of fluorescent reagents that may be used to screen samples for the presence of specific sequences. The apparatus works by associating extracted and purified sample with a series of reagent plugs that have been formed in a flow channel and delivered to a flow-through real-time amplification detector that has a multiplicity of optical windows, to which the sample-reagent plugs are placed in an operative position. The diagnostic apparatus includes sample multi-position valves, a master sample multi-position valve, a master reagent multi-position valve, reagent multi-position valves, and an optical amplification/detection system.

Identifying Coherent Structures in a 3-Stream Supersonic Jet Flow using Time-Resolved Schlieren Imaging

NASA Astrophysics Data System (ADS)

Tenney, Andrew; Coleman, Thomas; Berry, Matthew; Magstadt, Andy; Gogineni, Sivaram; Kiel, Barry

2015-11-01

Shock cells and large scale structures present in a three-stream non-axisymmetric jet are studied both qualitatively and quantitatively. Large Eddy Simulation is utilized first to gain an understanding of the underlying physics of the flow and direct the focus of the physical experiment. The flow in the experiment is visualized using long exposure Schlieren photography, with time resolved Schlieren photography also a possibility. Velocity derivative diagnostics are calculated from the grey-scale Schlieren images are analyzed using continuous wavelet transforms. Pressure signals are also captured in the near-field of the jet to correlate with the velocity derivative diagnostics and assist in unraveling this complex flow. We acknowledge the support of AFRL through an SBIR grant.

Experimental paradigm for in-lab proxy aquatic studies under conditions of static, non flow through chemical exposures

EPA Science Inventory

Endocrine disrupting chemicals (EDCs) such as 17α ethynylestradiol (EE2), 17β estradiol (E2), estrone (E1) and para-nonylphenol (NP) have been measured in wastewater treatment plant effluents, surface waters, sediments and sludge, and have been shown to induce liver-sp...

Velocity lag of solid particles in oscillating gases and in gases passing through normal shock waves

NASA Technical Reports Server (NTRS)

Maxwell, B. R.; Seasholtz, R. G.

1974-01-01

The velocity lag of micrometer size spherical particles is theoretically determined for gas particle mixtures passing through a stationary normal shock wave and also for particles embedded in an oscillating gas flow. The particle sizes and densities chosen are those considered important for laser Doppler velocimeter applications. The governing equations for each flow system are formulated. The deviation from Stokes flow caused by inertial, compressibility, and rarefaction effects is accounted for in both flow systems by use of an empirical drag coefficient. Graphical results are presented which characterize particle tracking as a function of system parameters.

Effect of oxidant concentration, exposure time, and seed particles on secondary organic aerosol chemical composition and yield

NASA Astrophysics Data System (ADS)

Lambe, A. T.; Chhabra, P. S.; Onasch, T. B.; Brune, W. H.; Hunter, J. F.; Kroll, J. H.; Cummings, M. J.; Brogan, J. F.; Parmar, Y.; Worsnop, D. R.; Kolb, C. E.; Davidovits, P.

2015-03-01

We performed a systematic intercomparison study of the chemistry and yields of secondary organic aerosol (SOA) generated from OH oxidation of a common set of gas-phase precursors in a Potential Aerosol Mass (PAM) continuous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH concentrations ranging from 2.0 × 108 to 2.2 × 1010 molec cm-3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH concentrations ranging from 2 × 106 to 2 × 107 molec cm-3 over exposure times of several hours. The OH concentration in the chamber experiments is close to that found in the atmosphere, but the integrated OH exposure in the flow reactor can simulate atmospheric exposure times of multiple days compared to chamber exposure times of only a day or so. In most cases, for a specific SOA type the most-oxidized chamber SOA and the least-oxidized flow reactor SOA have similar mass spectra, oxygen-to-carbon and hydrogen-to-carbon ratios, and carbon oxidation states at integrated OH exposures between approximately 1 × 1011 and 2 × 1011 molec cm-3 s, or about 1-2 days of equivalent atmospheric oxidation. This observation suggests that in the range of available OH exposure overlap for the flow reactor and chambers, SOA elemental composition as measured by an aerosol mass spectrometer is similar whether the precursor is exposed to low OH concentrations over long exposure times or high OH concentrations over short exposure times. This similarity in turn suggests that both in the flow reactor and in chambers, SOA chemical composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors rather than heterogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than measured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed particles are routinely used.

Photonic crystal biosensor microplates with integrated fluid networks for high throughput applications in drug discovery

NASA Astrophysics Data System (ADS)

Choi, Charles J.; Chan, Leo L.; Pineda, Maria F.; Cunningham, Brian T.

2007-09-01

Assays used in pharmaceutical research require a system that can not only detect biochemical interactions with high sensitivity, but that can also perform many measurements in parallel while consuming low volumes of reagents. While nearly all label-free biosensor transducers to date have been interfaced with a flow channel, the liquid handling system is typically aligned and bonded to the transducer for supplying analytes to only a few sensors in parallel. In this presentation, we describe a fabrication approach for photonic crystal biosensors that utilizes nanoreplica molding to produce a network of sensors that are automatically self-aligned with a microfluidic network in a single process step. The sensor/fluid network is inexpensively produced on large surface areas upon flexible plastic substrates, allowing the device to be incorporated into standard format 96-well microplates. A simple flow scheme using hydrostatic pressure applied through a single control point enables immobilization of capture ligands upon a large number of sensors with 220 nL of reagent, and subsequent exposure of the sensors to test samples. A high resolution imaging detection instrument is capable of monitoring the binding within parallel channels at rates compatible with determining kinetic binding constants between the immobilized ligands and the analytes. The first implementation of this system is capable of monitoring the kinetic interactions of 11 flow channels at once, and a total of 88 channels within an integrated biosensor microplate in rapid succession. The system was initially tested to characterize the interaction between sets of proteins with known binding behavior.

Personal Computer System for Automatic Coronary Venous Flow Measurement

PubMed Central

Dew, Robert B.

1985-01-01

We developed an automated system based on an IBM PC/XT Personal computer to measure coronary venous blood flow during cardiac catheterization. Flow is determined by a thermodilution technique in which a cold saline solution is infused through a catheter into the coronary venous system. Regional temperature fluctuations sensed by the catheter are used to determine great cardiac vein and coronary sinus blood flow. The computer system replaces manual methods of acquiring and analyzing temperature data related to flow measurement, thereby increasing the speed and accuracy with which repetitive flow determinations can be made.

Generalized Fluid System Simulation Program (GFSSP) Version 6 - General Purpose Thermo-Fluid Network Analysis Software

NASA Technical Reports Server (NTRS)

Majumdar, Alok; Leclair, Andre; Moore, Ric; Schallhorn, Paul

2011-01-01

GFSSP stands for Generalized Fluid System Simulation Program. It is a general-purpose computer program to compute pressure, temperature and flow distribution in a flow network. GFSSP calculates pressure, temperature, and concentrations at nodes and calculates flow rates through branches. It was primarily developed to analyze Internal Flow Analysis of a Turbopump Transient Flow Analysis of a Propulsion System. GFSSP development started in 1994 with an objective to provide a generalized and easy to use flow analysis tool for thermo-fluid systems.

Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.; Schunk, Richard G.

2011-01-01

An active thermal control system architecture has been modified to include a regenerative heat exchanger (regenerator) inboard of the radiator. Rather than using a radiator bypass valve a regenerative heat exchanger is placed inboard of the radiators. A regenerator cold side bypass valve is used to set the return temperature. During operation, the regenerator bypass flow is varied, mixing cold radiator return fluid and warm regenerator outlet fluid to maintain the system setpoint. At the lowest heat load for stable operation, the bypass flow is closed off, sending all of the flow through the regenerator. This lowers the radiator inlet temperature well below the system set-point while maintaining full flow through the radiators. By using a regenerator bypass flow control to maintain system setpoint, the required minimum heat load to avoid radiator freezing can be reduced by more than half compared to a radiator bypass system.

Sensor Fish Characterization of Fish Passage Conditions through John Day Dam Spillbay 20 with a Modified Flow Deflector

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

Duncan, Joanne P.

Fish passage conditions over a modified deflector in Spillbay 20 at John Day Dam were evaluated by Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers (USACE), Portland District, using Sensor Fish devices. The objectives of the study were to describe and compare passage exposure conditions at two spill discharges, 2.4 and 4.0 thousand cubic feet per second (kcfs), identifying potential fish injury regions within the routes, and to evaluate a low-tailwater condition at the 2.4-kcfs discharge. The study was performed in April 2010 concurrent with HI-Z balloon-tag studies by Normandeau Associates, Inc. Sensor Fish data were analyzedmore » to estimate 1) exposure conditions, particularly exposure to severe collision and shear events; 2) differences in passage conditions between treatments; and 3) relationships to live-fish injury and mortality data estimates. Nearly all Sensor Fish significant events were classified as collisions; the most severe occurred at the gate, on the spillbay chute, or at the deflector transition. Collisions in the gate region were observed only during the 2.4-kcfs discharge, when the tainter gate was open 1.2 ft. One shear event was observed during the evaluation, occurring at the deflector transition during passage at the 2.4-kcfs discharge at low tailwater. Flow quality, computed using the Sensor Fish turbulence index, was best for passage at the low-flow low-tailwater condition as well. The worst flow quality was observed for the 4.0-kcfs test condition. Contrasting the passage exposure conditions, the 2.4-kcfs low-tailwater treatment would be most deleterious to fish survival and well-being.« less

Self-actuated nuclear reactor shutdown system using induction pump to facilitate sensing of core coolant temperature

DOEpatents

Sievers, Robert K.; Cooper, Martin H.; Tupper, Robert B.

1987-01-01

A self-actuated shutdown system incorporated into a reactivity control assembly in a nuclear reactor includes pumping means for creating an auxiliary downward flow of a portion of the heated coolant exiting from the fuel assemblies disposed adjacent to the control assembly. The shutdown system includes a hollow tubular member which extends through the outlet of the control assembly top nozzle so as to define an outer annular flow channel through the top nozzle outlet separate from an inner flow channel for primary coolant flow through the control assembly. Also, a latching mechanism is disposed in an inner duct of the control assembly and is operable for holding absorber bundles in a raised position in the control assembly and for releasing them to drop them into the core of the reactor for shutdown purposes. The latching mechanism has an inner flow passage extending between and in flow communication with the absorber bundles and the inner flow channel of the top nozzle for accommodating primary coolant flow upwardly through the control assembly. Also, an outer flow passage separate from the inner flow passage extends through the latching mechanism between and in flow communication with the inner duct and the outer flow channel of the top nozzle for accommodating inflow of a portion of the heated coolant from the adjacent fuel assemblies. The latching mechanism contains a magnetic material sensitive to temperature and operable to cause mating or latching together of the components of the latching mechanism when the temperature sensed is below a known temperature and unmating or unlatching thereof when the temperature sensed is above a given temperature. The temperature sensitive magnetic material is positioned in communication with the heated coolant flow through the outer flow passage for directly sensing the temperature thereof. Finally, the pumping means includes a jet induction pump nozzle and diffuser disposed adjacent the bottom nozzle of the control assembly and in flow communication with the inlet thereof. The pump nozzle is operable to create an upward driving flow of primary coolant through the pump diffuser and then to the absorber bundles. The upward driving flow of primary coolant, in turn, creates a suction head within the outer flow channel of the top nozzle and thereby an auxiliary downward flow of the heated coolant portion exiting from the upper end of the adjacent fuel assemblies through the outer flow channel to the pump nozzle via the outer flow passage of the latching mechanism and an annular space between the outer and inner spaced ducts of the control assembly housing. The temperature of the heated coolant exiting from the adjacent fuel assemblies can thereby be sensed directly by the temperature sensitive magnetic material in the latching mechanism.

Cyber Situational Awareness through Operational Streaming Analysis

DTIC Science & Technology

2011-04-07

Our system makes use of two specific data sources from network traffic: raw packet data and NetFlow connection summary records (de- scribed below...implemented an operational prototype system using the following two data feeds. a) NetFlow Data: Our system processes the NetFlow records of all...Internet gateway traffic for a large enterprise network. It uses the standard Cisco NetFlow version 5 proto- col, which defines a flow as a

Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing.

PubMed

Donaldsson, Snorri; Falk, Markus; Jonsson, Baldvin; Drevhammar, Thomas

2015-01-01

The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing. Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically. The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance. The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.

Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing

PubMed Central

2015-01-01

Background The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing. Methods Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically. Results The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance. Conclusion The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates. PMID:26192188

Characterization of Carbon Dioxide Washout Measurement Techniques in the Mark-III Space Suit

NASA Technical Reports Server (NTRS)

Norcross, J.; Bekdash, O.; Meginnis, I.

2016-01-01

Providing adequate carbon dioxide (CO2) washout is essential to the reduction of risk in performing suited operations. Long term CO2 exposure can lead to symptoms such as headache, lethargy, dizziness, and in severe cases can lead to unconsciousness and death. Thus maintaining adequate CO2 washout in both ground testing and during in flight EVAs is a requirement of current and future suit designs. It is necessary to understand the inspired CO2 of suit wearers such that future requirements for space suits appropriately address the risk of inadequate washout. Testing conducted by the EVA Physiology Laboratory at the NASA Johnson Space Center aimed to characterize a method for noninvasively measuring inspired oronasal CO2 under pressurized suited conditions in order to better inform requirements definition and verification techniques for future CO2 washout limits in space suits. Prior work conducted by the EPL examined several different wearable, respirator style, masks that could be used to sample air from the vicinity surround the nose and mouth of a suited test subject. Previously published studies utilized these masks, some being commercial products and some novel designs, to monitor CO2 under various exercise and flow conditions with mixed results for repeatability and/or consistency between subjects. Based on a meta-analysis of those studies it was decided to test a nasal cannula as it is a commercially available device that is placed directly in the flow path of the user as they breathe. A nasal cannula was used to sample air inhaled by the test subjects during both rest and exercise conditions. Eight subjects were tasked with walking on a treadmill or operating an arm ergometer to reach target metabolic rates of 1000, 2000, and 3000 BTU/hr. Suit pressure was maintained at 4.3 psid for all tests, with supply flow rates of 6, 4, and 2 actual cubic feet per minute depending on the test condition. Each test configuration was conducted twice with subjects breathing either through their nose only, or however they felt comfortable. By restricting breathing through a single orifice, we are able to more accurately define exactly what flow stream the sampled CO2 is taken from. Oronasal CO2 was monitored using real time infrared gas analyzers fed via sample tubes connected to the nasal cannula within the suit. Two additional sampling tubes were placed at the head and chin of the test subject, in an effort to capture CO2 concentrations across the entire flow stream of the Mark-III vent system (flow path is head to neck). Metabolic rate was calculated via the exhaust CO2 concentration and used to adjust subject workload on either the treadmill or arm ergometer until the target was reached. Forward work will aim to characterize the historically accepted minimum ppCO2 in suit during EVA by repeating this study in the Extravehicular Mobility Unit (EMU) space suit. This will help to define washout requirements for future suits, be they NASA (e.g. Z-2) or Commercial Crew designed. Additionally it is important to determine the functional consequences of CO2 exposure during EVA. Severe CO2 symptoms are a result of very high concentration, acute exposures. While long term, low concentration exposures have been shown to result in slight cognitive decline, symptoms resolve upon quickly returning to nominal concentrations and it remains unknown the impact that minor deficits in cognitive performance can have on EVA performance.

Gravity flow rate of solids through orifices and pipes

NASA Technical Reports Server (NTRS)

Gardner, J. F.; Smith, J. E.; Hobday, J. M.

1977-01-01

Lock-hopper systems are the most common means for feeding solids to and from coal conversion reactor vessels. The rate at which crushed solids flow by gravity through the vertical pipes and valves in lock-hopper systems affects the size of pipes and valves needed to meet the solids-handling requirements of the coal conversion process. Methods used to predict flow rates are described and compared with experimental data. Preliminary indications are that solids-handling systems for coal conversion processes are over-designed by a factor of 2 or 3.

Analytical verification of waterborne chemical treatment regimens in hatchery raceways

USGS Publications Warehouse

Rach, J.J.; Ramsay, R.T.

2000-01-01

Chemical therapy for control and prevention of fish diseases is a necessary and common practice in aquaculture. Many factors affect the accuracy of a chemical treatment application, such as the functioning of the chemical delivery system, calculation of chemical quantities to be delivered, water temperature, geometry of the culture unit, inlet-outlet structure, the influence of aerators, wind movement, and measurement of water volumes and flow rates. Three separate trials were conducted at the Osceola Fish Hatchery, a facility of the Wisconsin Department of Natural Resources, evaluating the accuracy of flow-through hydrogen peroxide treatments applied to 1, 3, or 9 raceways that were connected in series. Raceways were treated with 50 or 75 ??L/L of hydrogen peroxide for 30 min. Chemical concentrations were determined titrimetrically. The target treatment regimen was not realized in any of the applications. Chemical concentrations dropped and exposure times increased with each additional raceway treated in series. Single introduction of a therapeutant to more than three raceways in series is not recommended. Factors that interfered with the accuracy of the treatments were culture unit configuration, aeration, and flow rates. Several treatment modifications were identified that would result in more accurate chemical treatments.

Water Contaminant Mitigation in Ionic Liquid Propellant

NASA Technical Reports Server (NTRS)

Conroy, David; Ziemer, John

2009-01-01

Appropriate system and operational requirements are needed in order to ensure mission success without unnecessary cost. Purity requirements applied to thruster propellants may flow down to materials and operations as well as the propellant preparation itself. Colloid electrospray thrusters function by applying a large potential to a room temperature liquid propellant (such as an ionic liquid), inducing formation of a Taylor cone. Ions and droplets are ejected from the Taylor cone and accelerated through a strong electric field. Electrospray thrusters are highly efficient, precise, scaleable, and demonstrate low thrust noise. Ionic liquid propellants have excellent properties for use as electrospray propellants, but can be hampered by impurities, owing to their solvent capabilities. Of foremost concern is the water content, which can result from exposure to atmosphere. Even hydrophobic ionic liquids have been shown to absorb water from the air. In order to mitigate the risks of bubble formation in feed systems caused by water content of the ionic liquid propellant, physical properties of the ionic liquid EMI-Im are analyzed. The effects of surface tension, material wetting, physisorption, and geometric details of the flow manifold and electrospray emitters are explored. Results are compared to laboratory test data.

Improved radiation dose efficiency in solution SAXS using a sheath flow sample environment

PubMed Central

Kirby, Nigel; Cowieson, Nathan; Hawley, Adrian M.; Mudie, Stephen T.; McGillivray, Duncan J.; Kusel, Michael; Samardzic-Boban, Vesna; Ryan, Timothy M.

2016-01-01

Radiation damage is a major limitation to synchrotron small-angle X-ray scattering analysis of biomacromolecules. Flowing the sample during exposure helps to reduce the problem, but its effectiveness in the laminar-flow regime is limited by slow flow velocity at the walls of sample cells. To overcome this limitation, the coflow method was developed, where the sample flows through the centre of its cell surrounded by a flow of matched buffer. The method permits an order-of-magnitude increase of X-ray incident flux before sample damage, improves measurement statistics and maintains low sample concentration limits. The method also efficiently handles sample volumes of a few microlitres, can increase sample throughput, is intrinsically resistant to capillary fouling by sample and is suited to static samples and size-exclusion chromatography applications. The method unlocks further potential of third-generation synchrotron beamlines to facilitate new and challenging applications in solution scattering. PMID:27917826

System and method for reducing combustion dynamics in a combustor

DOEpatents

Uhm, Jong Ho; Johnson, Thomas Edward; Zuo, Baifang; York, William David

2013-08-20

A system for reducing combustion dynamics in a combustor includes an end cap having an upstream surface axially separated from a downstream surface, and tube bundles extend through the end cap. A diluent supply in fluid communication with the end cap provides diluent flow to the end cap. Diluent distributors circumferentially arranged inside at least one tube bundle extend downstream from the downstream surface and provide fluid communication for the diluent flow through the end cap. A method for reducing combustion dynamics in a combustor includes flowing fuel through tube bundles that extend axially through an end cap, flowing a diluent through diluent distributors into a combustion chamber, wherein the diluent distributors are circumferentially arranged inside at least one tube bundle and each diluent distributor extends downstream from the end cap, and forming a diluent barrier in the combustion chamber between at least one pair of adjacent tube bundles.

Locomotive Recalibration and Prism Adaptation of Children and Teens in Immersive Virtual Environments.

PubMed

Adams, Haley; Narasimham, Gayathri; Rieser, John; Creem-Regehr, Sarah; Stefanucci, Jeanine; Bodenheimer, Bobby

2018-04-01

As virtual reality expands in popularity, an increasingly diverse audience is gaining exposure to immersive virtual environments (IVEs). A significant body of research has demonstrated how perception and action work in such environments, but most of this work has been done studying adults. Less is known about how physical and cognitive development affect perception and action in IVEs, particularly as applied to preteen and teenage children. Accordingly, in the current study we assess how preteens (children aged 8-12 years) and teenagers (children aged 15-18 years) respond to mismatches between their motor behavior and the visual information presented by an IVE. Over two experiments, we evaluate how these individuals recalibrate their actions across functionally distinct systems of movement. The first experiment analyzed forward walking recalibration after exposure to an IVE with either increased or decreased visual flow. Visual flow during normal bipedal locomotion was manipulated to be either twice or half as fast as the physical gait. The second experiment leveraged a prism throwing adaptation paradigm to test the effect of recalibration on throwing movement. In the first experiment, our results show no differences across age groups, although subjects generally experienced a post-exposure effect of shortened distance estimation after experiencing visually faster flow and longer distance estimation after experiencing visually slower flow. In the second experiment, subjects generally showed the typical prism adaptation behavior of a throwing after-effect error. The error lasted longer for preteens than older children. Our results have implications for the design of virtual systems with children as a target audience.

Ultraviolet-B radiation mobilizes uranium from uranium-dissolved organic carbon complexes in aquatic systems, demonstrated by asymmetrical flow field-flow fractionation.

PubMed

Nehete, Sachin Vilas; Christensen, Terje; Salbu, Brit; Teien, Hans-Christian

2017-05-05

Humic substances have a tendency to form complexes with metal ions in aquatic medium, impacting the metal mobility, decreasing bioavailability and toxicity. Ultraviolet-B (UV-B) radiation exposure degrades the humic substance, changes their molecular weight distribution and their metal binding capacity in aquatic medium. In this study, we experimented the effect of UV-B radiation on the uranium complexed with fulvic acids and humic acids in a soft water system at different pH, uranium concentrations and radiant exposure. The concentration and distribution of uranium in a complexed form were investigated by asymmetrical flow field-flow fractionation coupled to multi detection technique (AsFlFFF-UV-ICP-MS). The major concentration of uranium present in complexes was primarily associated with average and higher molecular weight fulvic and humic acids components. The concentration of uranium in a complexed form increased with increasing fulvic and humic acid concentrations as well as pH of the solution. The higher molecular weight fraction of uranium was degraded due to the UV-B exposure, transforming about 50% of the uranium-dissolved organic carbon complexes into low molecular weight uranium species in complex form with organic ligands and/or free form. The result also suggests AsFlFFF-UV-ICP-MS to be an important separation and detection technique for understanding the interaction of radionuclides with dissolved organic matter, tracking size distribution changes during degradation of organic complexes for understanding mobility, bioavailability and ecosystem transfer of radionuclides as well as metals. Copyright © 2017 Elsevier B.V. All rights reserved.

Chronic toxicity of erythromycin thiocyanate to Daphnia magna in a flow-through, continuous exposure test system

USGS Publications Warehouse

Meinertz, J.R.; Schreier, Theresa M.; Bernardy, J.A.

2011-01-01

Approval of a new animal drug application for AQUAMYCIN 100?? (erythromycin thiocyanate; ET) to treat freshwater salmonid species with bacterial kidney disease is being pursued in the US. As part of the approval process, ETs impact on an aquatic environment had to be described in an environmental assessment. The environmental assessment was lacking data to characterize the effect ET would have on a chronically exposed aquatic invertebrate organism. A major step to fulfilling the environmental assessment was completed after conducting a comprehensive study continuously exposing Daphnia magna to ET for 21 days. Results indicated that the no observable effect concentration for ET was 179 ??g/L. ?? 2011 Springer Science+Business Media, LLC (outside the USA).

Characterization of a Latent Virus-Like Infection of Symbiotic Zooxanthellae▿

PubMed Central

Lohr, Jayme; Munn, Colin B.; Wilson, William H.

2007-01-01

A latent virus-like agent, which we designated zooxanthella filamentous virus 1 (ZFV1), was isolated from Symbiodinium sp. strain CCMP 2465 and characterized. Transmission electron microscopy and analytical flow cytometry revealed the presence of a new group of distinctive filamentous virus-like particles after exposure of the zooxanthellae to UV light. Examination of thin sections of the zooxanthellae revealed the formation and proliferation of filamentous virus-like particles in the UV-induced cells. Assessment of Symbiodinium sp. cultures was used here as a model to show the effects of UV irradiance and induction of potential latent viruses. The unique host-virus system described here provides insight into the role of latent infections in zooxanthellae through environmentally regulated viral induction mechanisms. PMID:17351090

Characterization of a latent virus-like infection of symbiotic zooxanthellae.

PubMed

Lohr, Jayme; Munn, Colin B; Wilson, William H

2007-05-01

A latent virus-like agent, which we designated zooxanthella filamentous virus 1 (ZFV1), was isolated from Symbiodinium sp. strain CCMP 2465 and characterized. Transmission electron microscopy and analytical flow cytometry revealed the presence of a new group of distinctive filamentous virus-like particles after exposure of the zooxanthellae to UV light. Examination of thin sections of the zooxanthellae revealed the formation and proliferation of filamentous virus-like particles in the UV-induced cells. Assessment of Symbiodinium sp. cultures was used here as a model to show the effects of UV irradiance and induction of potential latent viruses. The unique host-virus system described here provides insight into the role of latent infections in zooxanthellae through environmentally regulated viral induction mechanisms.

Investigations into the Effect of Current Velocity on Amidoxime-Based Polymeric Uranium Adsorbent Performance

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

Gill, Gary A.; Kuo, Li-Jung; Strivens, Jonathan E.

2015-12-01

The Fuel Resources Program at the U.S. Department of Energy’s (DOE), Office of Nuclear Energy (DOE-NE) is developing adsorbent technology to extract uranium from seawater. This technology is being developed to provide a sustainable and economically viable supply of uranium fuel for nuclear reactors (DOE, 2010). Among the key environmental variables to understand for adsorbent deployment in the coastal ocean is what effect flow-rates or linear velocity has on uranium adsorption capacity. The goal is to find a flow conditions that optimize uranium adsorption capacity in the shortest exposure time. Understanding these criteria will be critical in choosing a locationmore » for deployment of a marine adsorbent farm. The objective of this study was to identify at what linear velocity the adsorption kinetics for uranium extraction starts to drop off due to limitations in mass transport of uranium to the surface of the adsorbent fibers. Two independent laboratory-based experimental approaches using flow-through columns and recirculating flumes for adsorbent exposure were used to assess the effect of flow-rate (linear velocity) on the kinetic uptake of uranium on amidoxime-based polymeric adsorbent material. Time series observations over a 56 day period were conducted with flow-through columns over a 35-fold range in linear velocity from 0.29 to 10.2 cm/s, while the flume study was conducted over a narrower 11-fold range, from 0.48 to 5.52 cm/s. These ranges were specifically chosen to focus on the lower end of oceanic currents and expand above and below the linear velocity of ~ 2.5 cm/s adopted for marine testing of adsorbent material at PNNL.« less

Noise exposure is increased with neonatal helmet CPAP in comparison with conventional nasal CPAP.

PubMed

Trevisanuto, D; Camiletti, L; Doglioni, N; Cavallin, F; Udilano, A; Zanardo, V

2011-01-01

in adults, noninvasive ventilation via a helmet is associated with significantly greater noise than nasal and facial masks. We hypothesized that noise exposure could be increased with neonatal helmet continuous positive airway pressure (CPAP) in comparison with conventional nasal CPAP (nCPAP). Our primary objective was to compare the noise intensity produced by a neonatal helmet CPAP and a conventional nCPAP system. Furthermore, we aimed to evaluate the effect of the gas flow rate and the presence of the humidifier and the filter on noise levels during neonatal helmet CPAP treatment. in this bench study, noise intensity was measured in the following settings: helmet CPAP, nCPAP, incubator and the neonatal intensive care unit. In helmet CPAP, noise measurements were performed at different gas flow rates (8, 10 and 12 l/min), while in nCPAP, the flow rate was 8 l/min. For both CPAP systems, the level of pressure was maintained constant at 5 cmH(2) O. during neonatal helmet CPAP, the median (interquartile range) noise levels were significantly higher than those during nCPAP: 70.0 dB (69.9-70.4) vs. 62.7 dB (62.5-63.0); P<0.001. In the helmet CPAP, the noise intensities changed with increasing flow rate and with the presence of a humidifier or a filter. noise intensities generated by the neonatal helmet CPAP were significantly higher than those registered while using a conventional nCPAP system. In the helmet, the noise intensity depends on the gas flow rate, and the presence of a humidifier and a filter in the system. 2010 The Acta Anaesthesiologica Scandinavica Foundation.

The impact of fluid advection on gas hydrate stability: Investigations at sites of methane seepage offshore Costa Rica

NASA Astrophysics Data System (ADS)

Crutchley, G. J.; Klaeschen, D.; Planert, L.; Bialas, J.; Berndt, C.; Papenberg, C.; Hensen, C.; Hornbach, M. J.; Krastel, S.; Brueckmann, W.

2014-09-01

Fluid flow through marine sediments drives a wide range of processes, from gas hydrate formation and dissociation, to seafloor methane seepage including the development of chemosynthetic ecosystems, and ocean acidification. Here, we present new seismic data that reveal the 3D nature of focused fluid flow beneath two mound structures on the seafloor offshore Costa Rica. These mounds have formed as a result of ongoing seepage of methane-rich fluids. We show the spatial impact of advective heat flow on gas hydrate stability due to the channelled ascent of warm fluids towards the seafloor. The base of gas hydrate stability (BGHS) imaged in the seismic data constrains peak heat flow values to ∼60 mW m and ∼70 mW m beneath two separate seep sites known as Mound 11 and Mound 12, respectively. The initiation of pronounced fluid flow towards these structures was likely controlled by fault networks that acted as efficient pathways for warm fluids ascending from depth. Through the gas hydrate stability zone, fluid flow has been focused through vertical conduits that we suggest developed as migrating fluids generated their own secondary permeability by fracturing strata as they forced their way upwards towards the seafloor. We show that Mound 11 and Mound 12 (about 1 km apart on the seafloor) are sustained by independent fluid flow systems through the hydrate system, and that fluid flow rates across the BGHS are probably similar beneath both mounds. 2D seismic data suggest that these two flow systems might merge at approximately 1 km depth, i.e. much deeper than the BGHS. This study provides a new level of detail and understanding of how channelled, anomalously-high fluid flow towards the seafloor influences gas hydrate stability. Thus, gas hydrate systems have good potential for quantifying the upward flow of subduction system fluids to seafloor seep sites, since the fluids have to interact with and leave their mark on the hydrate system before reaching the seafloor.

Alpha adrenergic regulation of celiac blood flow and plasma catecholamine response during acute heat stress in fed cockerels.

PubMed

Bottje, W G; Harrison, P C

1986-08-01

Hubbard cockerels with chronically implanted electromagnetic blood flow probes on the celiac artery were used to establish a relationship between changes in postprandial celiac mean blood flow (MBF) and plasma catecholamines during a acute heat exposure. Five min after the elevation of ambient temperature from 25 to 37 C, there were concomitant reductions (P less than .05) in celiac MBF, norepinephrine (NE), and heart rate (HR). After 50 min of heat stress, rectal temperature (Tr), respiratory rate (RR), plasma epinephrine (E), and celiac vascular resistance (CVR) were significantly greater (P less than .05) than preheat stress thermoneutral control values. During the thermoneutral recovery period, all parameters returned to values comparable to preheat exposure control with the exception of NE, which tended (P less than .1) to remain lower. To determine the role of the sympathetic nervous system in regulating postprandial celiac MBF during acute heat exposure, chronically instrumented cockerels were infused with phenoxybenzamine, an alpha-adrenergic receptor-blocking agent. Alpha-receptor blockade attenuated both postprandial intestinal hyperemia under thermoneutral conditions as well as the heat-induced reduction of postprandial celiac MBF. The results of these studies implicate the sympathetic nervous system in the regulation of postprandial celiac MBF in heat-stressed cockerels and indicate a possible alpha-adrenergic-mediated mechanism involved in postprandial intestinal hyperemia.

Modeling the changes in the concentration of aromatic hydrocarbons from an oil-coated gravel column

NASA Astrophysics Data System (ADS)

Jung, Jee-Hyun; Kang, Hyun-Joong; Kim, Moonkoo; Yim, Un Hyuk; An, Joon Geon; Shim, Won Joon; Kwon, Jung-Hwan

2015-12-01

The performance of a lab-scale flow-through exposure system designed for the evaluation of ecotoxicity due to oil spills was evaluated. The system simulates a spill event using an oil-coated gravel column through which filtered seawater is passed and flows into an aquarium containing fish embryos of olive flounder ( Paralichthys olivaceus) and spotted sea bass ( Lateolabrax maculates). The dissolved concentrations of individual polycyclic aromatic hydrocarbons (PAHs) in the column effluent were monitored and compared with theoretical solubilities predicted by Raoult's law. The effluent concentrations after 24 and 48 h were close to the theoretical predictions for the higher molecular weight PAHs, whereas the measured values for the lower molecular weight PAHs were lower than predicted. The ratios of the concentration of PAHs in flounder embryos to that in seawater were close to the lipid-water partition coefficients for the less hydrophobic PAHs, showing that equilibrium was attained between embryos and water. On the other hand, 48 h were insufficient to attain phase equilibrium for the more hydrophobic PAHs, indicating that the concentration in fish embryos may be lower than expected by equilibrium assumption. The results indicate that the equilibrium approach may be suitable for less hydrophobic PAHs, whereas it might overestimate the effects of more hydrophobic PAHs after oil spills because phase equilibrium in an oil-seawater-biota system is unlikely to be achieved. The ecotoxicological endpoints that were affected within a few days are likely to be influenced mainly by moderately hydrophobic components such as 3-ring PAHs.

Hydrologic Analysis of Fort Leonard Wood, Missouri

DTIC Science & Technology

2015-08-01

of water available to FLW from the Roubidoux Creek drainage . In this case, because water is lost to the groundwater system while flowing through...taken from the Roubidoux Creek drainage . Roubidoux Creek is intermittent, and the stream loses water to the groundwater system as it flows through...13 Figure 5. FLW drainage divide

Operating manual for the digital data-collection system for flow-control structures

USGS Publications Warehouse

Rorabaugh, J.I.; Rapp, W.L.

1986-01-01

This manual was written to help the user operate and maintain the digital data collection system for flow control structures. The system is used to measure daily discharge through river control dams. These dams commonly have tainter gates which are raised and lowered to keep the upper pool level relatively constant as the river flow changes. In order to measure the flow through such a structure, the positions of the tainter gates and the headwater and tailwater elevations must be known. From these data, the flow through the structure can be calculated. A typical digital data collection system is shown. Digitizing devices are mounted on the hoisting mechanism of each gate, as well as at the headwater and tailwater gages. Data from these digitizers are then routed by electrical cables to a central console where they are displayed and recorded on paper tape. If the dam has locks, a pressure-sensitive switch located in the lock activates a counter in the console which keeps track of the number of times the lock is drained and filled. (USGS)

Application of optical correlation techniques to particle imaging velocimetry

NASA Technical Reports Server (NTRS)

Wernet, Mark P.; Edwards, Robert V.

1988-01-01

Pulsed laser sheet velocimetry yields nonintrusive measurements of velocity vectors across an extended 2-dimensional region of the flow field. The application of optical correlation techniques to the analysis of multiple exposure laser light sheet photographs can reduce and/or simplify the data reduction time and hardware. Here, Matched Spatial Filters (MSF) are used in a pattern recognition system. Usually MSFs are used to identify the assembly line parts. In this application, the MSFs are used to identify the iso-velocity vector contours in the flow. The patterns to be recognized are the recorded particle images in a pulsed laser light sheet photograph. Measurement of the direction of the partical image displacements between exposures yields the velocity vector. The particle image exposure sequence is designed such that the velocity vector direction is determined unambiguously. A global analysis technique is used in comparison to the more common particle tracking algorithms and Young's fringe analysis technique.

Indolic uremic solutes enhance procoagulant activity of red blood cells through phosphatidylserine exposure and microparticle release.

PubMed

Gao, Chunyan; Ji, Shuting; Dong, Weijun; Qi, Yushan; Song, Wen; Cui, Debin; Shi, Jialan

2015-10-28

Increased accumulation of indolic uremic solutes in the blood of uremic patients contributes to the risk of thrombotic events. Red blood cells (RBCs), the most abundant blood cells in circulation, may be a privileged target of these solutes. However, the effect of uremic solutes indoxyl sulfate (IS) and indole-3-acetic acid (IAA) on procoagulant activity (PCA) of erythrocyte is unclear. Here, RBCs from healthy adults were treated with IS and IAA (mean and maximal concentrations reported in uremic patients). Phosphatidylserine (PS) exposure of RBCs and their microparticles (MPs) release were labeled with Alexa Fluor 488-lactadherin and detected by flow cytometer. Cytosolic Ca(2+) ([Ca(2+)]) with Fluo 3/AM was analyzed by flow cytometer. PCA was assessed by clotting time and purified coagulation complex assays. We found that PS exposure, MPs generation, and consequent PCA of RBCs at mean concentrations of IS and IAA enhanced and peaked in maximal uremic concentrations. Moreover, 128 nM lactadherin, a PS inhibitor, inhibited over 90% PCA of RBCs and RMPs. Eryptosis or damage, by indolic uremic solutes was due to, at least partially, the increase of cytosolic [Ca(2+)]. Our results suggest that RBC eryptosis in uremic solutes IS and IAA plays an important role in thrombus formation through releasing RMPs and exposing PS. Lactadherin acts as an efficient anticoagulant in this process.

Detection of early changes in lung cell cytology by flow-systems analysis techniques. Progress report, October 1, 1976--June 30, 1977. [Damage induced by exposure to toxic agents associated with production of synthetic fuels from oil shale and coal

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

Steinkamp, J.A.; Hansen, K.M.; Wilson, J.S.

1977-07-01

This report summarizes results of continuing experiments to develop cytological and biochemical indicators for estimating damage to respiratory tract cells in animals exposed to toxic agents associated with production of synthetic fuels from oil shale and coal, the specific goal being the application of advanced flow-systems technologies to the detection of early atypical cellular changes in lung epithelium. The objectives of the program during the past 6 months were: to develop standard methods for lavaging lungs of several rodent species (hamster, rat, and mouse) to increase cell yield; initiate oil shale exposures in hamsters and rats; study the effects ofmore » macrophage mobility in the presence of oil shale; and determine the effects of different fixatives on lung cell morphology using electron microscopy. To develop standard methods for lavaging the respiratory tract of test animals, experiments were devised to increase cell yield with minimal debris and blood. Proteolytic enzymes such as trypsin were also tested but produced excessive amounts of fibrinated blood. Experimental animals were exposed to raw and spent oil shale particulates to determine if changes in lung cell differential counts and/or atypical cellular changes were noted. Since the multiparameter cell separator system was inoperative during this reporting period due to major modifications, including the addition of an uv krypton laser, emphasis was primarily on cytological techniques. As the flow-systems instrumentation becomes fully operational during the next month, automated analysis of respiratory tract cells and measurement of physical and biochemical properties as a function of exposure to toxic agents will continue.« less

RSDL decontamination of human skin contaminated with the nerve agent VX.

PubMed

Thors, L; Lindberg, S; Johansson, S; Koch, B; Koch, M; Hägglund, L; Bucht, A

2017-03-05

Dermal exposure to low volatile organophosphorus compounds (OPC) may lead to penetration through the skin and uptake in the blood circulation. Skin decontamination of toxic OPCs, such as pesticides and chemical warfare nerve agents, might therefore be crucial for mitigating the systemic toxicity following dermal exposure. Reactive skin decontamination lotion (RSDL) has been shown to reduce toxic effects in animals dermally exposed to the nerve agent VX. In the present study, an in vitro flow-through diffusion cell was utilized to evaluate the efficacy of RSDL for decontamination of VX exposed to human epidermis. In particular, the impact of timing in the initiation of decontamination and agent dilution in water was studied. The impact of the lipophilic properties of VX in the RSDL decontamination was additionally addressed by comparing chemical degradation in RSDL and decontamination efficacy between the VX and the hydrophilic OPC triethyl phosphonoacetate (TEPA). The epidermal membrane was exposed to 20, 75 or 90% OPC diluted in deionized water and the decontamination was initiated 5, 10, 30, 60 or 120min post-exposure. Early decontamination of VX with RSDL, initiated 5-10min after skin exposure, was very effective. Delayed decontamination initiated 30-60min post-exposure was less effective but still the amount of penetrated agent was significantly reduced, while further delayed start of decontamination to 120min resulted in very low efficacy. Comparing RSDL decontamination of VX with that of TEPA showed that the decontamination efficacy at high agent concentrations was higher for VX. The degradation mechanism of VX and TEPA during decontamination was dissected by 31 P NMR spectroscopy of the OPCs following reactions with RSDL and its three nucleophile components. The degradation rate was clearly associated with the high pH of the specific solution investigated; i.e. increased pH resulted in a more rapid degradation. In addition, the solubility of the OPC in RSDL also influenced the degradation rate since the degradation of VX was significantly faster when the NMR analysis was performed in the organic solvent acetonitrile compared to water. In conclusion, we have applied the in vitro flow-through diffusion cell for evaluation of skin decontamination procedures of human epidermis exposed to OPCs. It was demonstrated that early decontamination is crucial for efficient mitigation of epidermal penetration of VX and that almost complete removal of the nerve agent from the skin surface is possible. Our data also indicate that the pH of RSDL together with the solubility of OPC in RSDL are of primary importance for the decontamination efficacy. Copyright © 2017 Elsevier B.V. All rights reserved.

Do environmental factors affect male fathead minnow (Pimephales promelas) response to estrone? Part 1. Dissolved oxygen and sodium chloride.

PubMed

Feifarek, D J; Shappell, N W; Schoenfuss, H L

2018-01-01

Laboratory exposures indicate that estrogens and their mimics can cause endocrine disruption in male fishes, yet while studies of resident fish populations in estrogen-polluted waters support these findings, biomarker expression associated with field versus laboratory exposure to estrogenic endocrine disruptors (EDs) often differ dramatically. Two of the environmental parameters often found to vary in dynamic aquatic ecosystems were chosen (dissolved oxygen [DO] and sodium chloride concentrations) to assess their potential impact on ED exposure. In separate experiments, male fathead minnows (Pimephales promelas) were exposed to estrone (E1) a natural ED, under either two concentrations of DO, or two concentrations of sodium chloride, in a laboratory flow-through system. Morphological and hematological parameters were assessed. While vitellogenin concentrations were elevated with exposure to estrone (29 to 390ng/L), the effect on other indices were variable. Estrone exposure altered SSC, blood glucose, hematocrit, and hepatic and gonado-somatic index in 1 of 4 experiments, while it decreased body condition factor in 3 of 4 experiments. At the concentrations tested, no main effect differences (P<0.05) were found associated with DO or sodium chloride treatments, except in one experiment low DO resulted in a decrease in secondary sex characteristic score (SSC). The combination of DO or sodium chloride and E1 altered blood glucose in one experiment each. These results indicate the variability of fathead minnow response to estrone, even within the confines of controlled laboratory conditions. Published by Elsevier B.V.

Exercise Thermoregulation in Men after One and 24-hours of 6 Degree Head-Down Tilt

NASA Technical Reports Server (NTRS)

Ertl, A. C.; Dearborn, A. S.; Weldhofer, A. R.; Bernauer, E. M.; Greenleaf, J. E.

1998-01-01

Exercise thermoregulation exercise is dependent on heat loss by increased skin blood flow (convective and conductive heat loss) and through enhanced sweating (evaporative heat loss). Reduction of plasma volume (PV), increased plasma osmolality, physical deconditioning, and duration of exposure to simulated and actual microgravity reduces the ability to thermoregulate during exercise.

Effect of oxidant concentration, exposure time, and seed particles on secondary organic aerosol chemical composition and yield

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

Lambe, A. T.; Chhabra, P. S.; Onasch, T. B.

We performed a systematic intercomparison study of the chemistry and yields of secondary organic aerosol (SOA) generated from OH oxidation of a common set of gas-phase precursors in a Potential Aerosol Mass (PAM) continuous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH concentrations ranging from 2.0 × 10 8 to 2.2 × 10 10 molec cm -3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH concentrations ranging from 2 × 10 6 to 2 × 10 7 molec cm -3 over exposure times of severalmore » hours. The OH concentration in the chamber experiments is close to that found in the atmosphere, but the integrated OH exposure in the flow reactor can simulate atmospheric exposure times of multiple days compared to chamber exposure times of only a day or so. In most cases, for a specific SOA type the most-oxidized chamber SOA and the least-oxidized flow reactor SOA have similar mass spectra, oxygen-to-carbon and hydrogen-to-carbon ratios, and carbon oxidation states at integrated OH exposures between approximately 1 × 10 11 and 2 × 10 11 molec cm -3 s, or about 1–2 days of equivalent atmospheric oxidation. This observation suggests that in the range of available OH exposure overlap for the flow reactor and chambers, SOA elemental composition as measured by an aerosol mass spectrometer is similar whether the precursor is exposed to low OH concentrations over long exposure times or high OH concentrations over short exposure times. This similarity in turn suggests that both in the flow reactor and in chambers, SOA chemical composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors rather than heterogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than measured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed particles are routinely used.« less

Effect of oxidant concentration, exposure time, and seed particles on secondary organic aerosol chemical composition and yield

DOE PAGES

Lambe, A. T.; Chhabra, P. S.; Onasch, T. B.; ...

2015-03-18

We performed a systematic intercomparison study of the chemistry and yields of secondary organic aerosol (SOA) generated from OH oxidation of a common set of gas-phase precursors in a Potential Aerosol Mass (PAM) continuous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH concentrations ranging from 2.0 × 10 8 to 2.2 × 10 10 molec cm -3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH concentrations ranging from 2 × 10 6 to 2 × 10 7 molec cm -3 over exposure times of severalmore » hours. The OH concentration in the chamber experiments is close to that found in the atmosphere, but the integrated OH exposure in the flow reactor can simulate atmospheric exposure times of multiple days compared to chamber exposure times of only a day or so. In most cases, for a specific SOA type the most-oxidized chamber SOA and the least-oxidized flow reactor SOA have similar mass spectra, oxygen-to-carbon and hydrogen-to-carbon ratios, and carbon oxidation states at integrated OH exposures between approximately 1 × 10 11 and 2 × 10 11 molec cm -3 s, or about 1–2 days of equivalent atmospheric oxidation. This observation suggests that in the range of available OH exposure overlap for the flow reactor and chambers, SOA elemental composition as measured by an aerosol mass spectrometer is similar whether the precursor is exposed to low OH concentrations over long exposure times or high OH concentrations over short exposure times. This similarity in turn suggests that both in the flow reactor and in chambers, SOA chemical composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors rather than heterogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than measured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed particles are routinely used.« less

Shallow Groundwater Movement in the Skagit River Delta Area, Skagit County, Washington

USGS Publications Warehouse

Savoca, Mark E.; Johnson, Kenneth H.; Fasser, Elisabeth T.

2009-01-01

Shallow groundwater movement in an area between the lower Skagit River and Puget Sound was characterized by the U.S. Geological Survey to assist Skagit County and the Washington State Department of Ecology with the identification of areas where water withdrawals from existing and new wells could adversely affect streamflow in the Skagit River. The shallow groundwater system consists of alluvial, lahar runout, and recessional outwash deposits composed of sand, gravel, and cobbles, with minor lenses of silt and clay. Upland areas are underlain by glacial till and outwash deposits that show evidence of terrestrial and shallow marine depositional environments. Bedrock exposures are limited to a few upland outcrops in the southwestern part of the study area, and consist of metamorphic, sedimentary, and igneous rocks. Water levels were measured in 47 wells on a quarterly basis (August 2007, November 2007, February 2008, and May 2008). Measurements from 34 wells completed in the shallow groundwater system were used to construct groundwater-level and flow-direction maps and perform a linear-regression analysis to estimate the overall, time averaged shallow groundwater-flow direction and gradient. Groundwater flow in the shallow groundwater system generally moves in a southwestward direction away from the Skagit River and toward the Swinomish Channel and Skagit Bay. Local groundwater flow towards the river was inferred during February 2008 in areas west and southwest of Mount Vernon. Water-level altitudes varied seasonally, however, and generally ranged from less than 3 feet (August 2007) in the west to about 15 feet (May 2008) in the east. The time-averaged, shallow groundwater-flow direction derived from regression analysis, 8.5 deg south of west, was similar to flow directions depicted on the quarterly water-level maps. Seasonal changes in groundwater levels in most wells in the Skagit River Delta follow a typical pattern for shallow wells in western Washington. Water levels rise from October through March, when precipitation is high, and decline from April through September, when precipitation is lower. Groundwater levels in wells along the eastern margin of the study area also are likely influenced by stage on the Skagit River. Water levels in these wells remained elevated through April, and did not seem to begin to decline until the end of May in response to declining river stage. Groundwater levels in a well equipped with a continuous water-level recorder exhibited periodic fluctuations that are characteristic of ocean tides. This well is less than 1 mile east of the tidally influenced Swinomish Channel, and exhibited water-level fluctuations that correspond closely to predicted tidal extremes obtained from a tide gage near La Conner, Washington.

Sterilization/disinfection using reduced-pressure plasmas: some differences between direct exposure of bacterial spores to a discharge and their exposure to a flowing afterglow

NASA Astrophysics Data System (ADS)

Moisan, M.; Levif, P.; Séguin, J.; Barbeau, J.

2014-07-01

The use of plasma for sterilization or disinfection offers a promising alternative to conventional steam or chemical approaches. Plasma can operate at temperatures less damaging to some heat-sensitive medical devices and, in contrast to chemicals, can be non-toxic and non-polluting for the operator and the environment, respectively. Direct exposure to the gaseous discharge (comprising an electric field and ions/electrons) or exposure to its afterglow (no E-field) can both be envisaged a priori, since these two methods can achieve sterility. However, important issues must be considered besides the sterility goal. Direct exposure to the discharge, although yielding a faster inactivation of microorganisms, is shown to be potentially more aggressive to materials and sometimes subjected to the shadowing effect that precludes the sterilization of complex-form items. These two drawbacks can be successfully minimized with an adequate flowing-afterglow exposure. Most importantly, the current paper shows that direct exposure to the discharge can lead to the dislodgment and release of viable microorganisms from their substratum. Such a phenomenon could be responsible for the recontamination of sterilized devices as well as possible contamination of the ambient surroundings, additionally yielding an erroneous over-appreciation of the inactivation efficiency. The operation of the N2-O2 flowing afterglow system being developed in our group is such that there are no ions and electrons left in the process chamber (late-afterglow regime) in full contrast with their presence in the discharge. The dislodgment and release of spores could be attributed, based on the literature, to their electrostatic charging by electrons, leading to an (outward) electrostatic stress that exceeds the adhesion of the spores on their substrate.

Effect of cadmium exposure on hepatopancreas and gills of the estuary mud crab (Scylla paramamosain): Histopathological changes and expression characterization of stress response genes.

PubMed

Zhu, Qi-Hui; Zhou, Zhong-Kai; Tu, Dan-Dan; Zhou, Yi-Lian; Wang, Cong; Liu, Ze-Peng; Gu, Wen-Bin; Chen, Yu-Yin; Shu, Miao-An

2018-02-01

Cadmium (Cd) is a heavy metal that accumulates easily in organisms and causes several detrimental effects, including tissue damage. Cd contamination from anthropogenic terrestrial sources flows into rivers, and through estuaries to the ocean. To evaluate the toxic effects of Cd on estuary crustaceans, we exposed the mud crab Scylla paramamosain to various Cd concentrations (0, 10.0, 20.0, and 40.0mg/L) for 24h. We also exposed mud crabs to a fixed Cd concentration (20.0mg/L) for various periods of time (0, 6, 12, 24, 48, and 72h). We observed that after exposure to Cd, the surfaces of the gill lamellae were wrinkled, and the morphologies of the nuclei and mitochondria in the hepatopancreas were altered. We analyzed the expression profiles of 36 stress-related genes after Cd exposure, including those encoding metallothioneins, heat shock proteins, apoptosis-related proteins, and antioxidant proteins, with quantitative reverse transcription PCR. We found that exposure to Cd altered gene expression, and that some genes might be suitable bioindicators of Cd stress. Gene expression profiles were organ-, duration-, and concentration-dependent, suggesting that stress-response genes might be involved in an innate defense system for handling heavy metal exposure. To the best of our knowledge, this study is the first one of histopathology and stress-response gene expression pattern of Scylla paramamosain after Cd exposure. Our work could increase our understanding of the effect of environmental toxins on estuary crustaceans. Copyright © 2017 Elsevier B.V. All rights reserved.

Bioconvection in Second Grade Nanofluid Flow Containing Nanoparticles and Gyrotactic Microorganisms

NASA Astrophysics Data System (ADS)

Khan, Noor Saeed

2018-04-01

The bioconvection in steady second grade nanofluid thin film flow containing nanoparticles and gyrotactic microorganisms is considered using passively controlled nanofluid model boundary conditions. A real-life system evolves under the flow and various taxis. The study is initially proposed in the context of gyrotactic system, which is used as a key element for the description of complex bioconvection patterns and dynamics in such systems. The governing partial differential equations are transformed into a system of ordinary ones through the similarity variables and solved analytically via homotopy analysis method (HAM). The solution is expressed through graphs and illustrated which show the influences of all the parameters.

Electrical system for a motor vehicle

DOEpatents

Tamor, Michael Alan

1999-01-01

In one embodiment of the present invention, an electrical system for a motor vehicle comprises a capacitor, an engine cranking motor coupled to receive motive power from the capacitor, a storage battery and an electrical generator having an electrical power output, the output coupled to provide electrical energy to the capacitor and to the storage battery. The electrical system also includes a resistor which limits current flow from the battery to the engine cranking motor. The electrical system further includes a diode which allows current flow through the diode from the generator to the battery but which blocks current flow through the diode from the battery to the cranking motor.

Electrical system for a motor vehicle

DOEpatents

Tamor, M.A.

1999-07-20

In one embodiment of the present invention, an electrical system for a motor vehicle comprises a capacitor, an engine cranking motor coupled to receive motive power from the capacitor, a storage battery and an electrical generator having an electrical power output, the output coupled to provide electrical energy to the capacitor and to the storage battery. The electrical system also includes a resistor which limits current flow from the battery to the engine cranking motor. The electrical system further includes a diode which allows current flow through the diode from the generator to the battery but which blocks current flow through the diode from the battery to the cranking motor. 2 figs.

Bioconvection in Second Grade Nanofluid Flow Containing Nanoparticles and Gyrotactic Microorganisms

NASA Astrophysics Data System (ADS)

Khan, Noor Saeed

2018-06-01

The bioconvection in steady second grade nanofluid thin film flow containing nanoparticles and gyrotactic microorganisms is considered using passively controlled nanofluid model boundary conditions. A real-life system evolves under the flow and various taxis. The study is initially proposed in the context of gyrotactic system, which is used as a key element for the description of complex bioconvection patterns and dynamics in such systems. The governing partial differential equations are transformed into a system of ordinary ones through the similarity variables and solved analytically via homotopy analysis method (HAM). The solution is expressed through graphs and illustrated which show the influences of all the parameters.

Assessing effects of a mining and municipal sewage effluent mixture on fathead minnow (Pimephales promelas) reproduction using a novel, field-based trophic-transfer artificial stream.

PubMed

Rickwood, Carrie J; Dubé, Monique G; Weber, Lynn P; Lux, Sarah; Janz, David M

2008-01-31

The Junction Creek watershed, located in Sudbury, ON, Canada receives effluent from three metal mine wastewater treatment plants, as well as a municipal wastewater (MWW) discharge. Effects on fish have been documented within the creek (decreased egg size and increased metal body burdens). It has been difficult to identify the cause of the effects observed due to the confounded nature of the creek. The objectives of this investigation were to assess the: (1) effects of a mine effluent and municipal wastewater (CCMWW) mixture on fathead minnow (FHM; Pimephales promelas) reproduction in an on-site artificial stream and (2) importance of food (Chironomus tentans) as a source of exposure using a trophic-transfer system. Exposures to CCMWW through the water significantly decreased egg production and spawning events. Exposure through food and water using the trophic-transfer system significantly increased egg production and spawning events. Embryos produced in the trophic-transfer system showed similar hatching success but increased incidence and severity of deformities after CCMWW exposure. We concluded that effects of CCMWW on FHM were more apparent when exposed through the water. Exposure through food and water may have reduced effluent toxicity, possibly due to increased nutrients and organic matter, which may have reduced metal bioavailability. More detailed examination of metal concentrations in the sediment, water column, prey (C. tentans) and FHM tissues is recommended to better understand the toxicokinetics of potential causative compounds within the different aquatic compartments when conducting exposures through different pathways.

Hyperspectral imaging flow cytometer

DOEpatents

Sinclair, Michael B.; Jones, Howland D. T.

2017-10-25

A hyperspectral imaging flow cytometer can acquire high-resolution hyperspectral images of particles, such as biological cells, flowing through a microfluidic system. The hyperspectral imaging flow cytometer can provide detailed spatial maps of multiple emitting species, cell morphology information, and state of health. An optimized system can image about 20 cells per second. The hyperspectral imaging flow cytometer enables many thousands of cells to be characterized in a single session.

Systems and methods for analyzing liquids under vacuum

DOEpatents

Yu, Xiao-Ying; Yang, Li; Cowin, James P.; Iedema, Martin J.; Zhu, Zihua

2013-10-15

Systems and methods for supporting a liquid against a vacuum pressure in a chamber can enable analysis of the liquid surface using vacuum-based chemical analysis instruments. No electrical or fluid connections are required to pass through the chamber walls. The systems can include a reservoir, a pump, and a liquid flow path. The reservoir contains a liquid-phase sample. The pump drives flow of the sample from the reservoir, through the liquid flow path, and back to the reservoir. The flow of the sample is not substantially driven by a differential between pressures inside and outside of the liquid flow path. An aperture in the liquid flow path exposes a stable portion of the liquid-phase sample to the vacuum pressure within the chamber. The radius, or size, of the aperture is less than or equal to a critical value required to support a meniscus of the liquid-phase sample by surface tension.

Flow-Control Systems Proof of Concept for Snowmelt Runoff at McMurdo Station, Antarctica

DTIC Science & Technology

2017-01-01

flows in the channels. However, the weirs became nonfunctional under high and surge flows. Experimental settling basins were constructed to... Results ................................................................................................................ 22 4.1 Flow and sediment...Runoff from the wa- tershed results almost exclusively from snowmelt, which passes through McMurdo via a system of drainage ditches, gullies, and

A hybrid solution using computational prediction and measured data to accurately determine process corrections with reduced overlay sampling

NASA Astrophysics Data System (ADS)

Noyes, Ben F.; Mokaberi, Babak; Mandoy, Ram; Pate, Alex; Huijgen, Ralph; McBurney, Mike; Chen, Owen

2017-03-01

Reducing overlay error via an accurate APC feedback system is one of the main challenges in high volume production of the current and future nodes in the semiconductor industry. The overlay feedback system directly affects the number of dies meeting overlay specification and the number of layers requiring dedicated exposure tools through the fabrication flow. Increasing the former number and reducing the latter number is beneficial for the overall efficiency and yield of the fabrication process. An overlay feedback system requires accurate determination of the overlay error, or fingerprint, on exposed wafers in order to determine corrections to be automatically and dynamically applied to the exposure of future wafers. Since current and future nodes require correction per exposure (CPE), the resolution of the overlay fingerprint must be high enough to accommodate CPE in the overlay feedback system, or overlay control module (OCM). Determining a high resolution fingerprint from measured data requires extremely dense overlay sampling that takes a significant amount of measurement time. For static corrections this is acceptable, but in an automated dynamic correction system this method creates extreme bottlenecks for the throughput of said system as new lots have to wait until the previous lot is measured. One solution is using a less dense overlay sampling scheme and employing computationally up-sampled data to a dense fingerprint. That method uses a global fingerprint model over the entire wafer; measured localized overlay errors are therefore not always represented in its up-sampled output. This paper will discuss a hybrid system shown in Fig. 1 that combines a computationally up-sampled fingerprint with the measured data to more accurately capture the actual fingerprint, including local overlay errors. Such a hybrid system is shown to result in reduced modelled residuals while determining the fingerprint, and better on-product overlay performance.

QIVIVE Approaches to Evaluate Interindividual Toxicokinetic Variability

EPA Science Inventory

Toxicokinetic (TK) variability across life-stages and populations can significantly impact the amount of chemical available systemically to elicit an effect despite similar external exposures. This variability is driven by physiologic (e.g., liver weights, blood flow rates, etc.)...

Stochastic Flow Cascades

NASA Astrophysics Data System (ADS)

Eliazar, Iddo I.; Shlesinger, Michael F.

2012-01-01

We introduce and explore a Stochastic Flow Cascade (SFC) model: A general statistical model for the unidirectional flow through a tandem array of heterogeneous filters. Examples include the flow of: (i) liquid through heterogeneous porous layers; (ii) shocks through tandem shot noise systems; (iii) signals through tandem communication filters. The SFC model combines together the Langevin equation, convolution filters and moving averages, and Poissonian randomizations. A comprehensive analysis of the SFC model is carried out, yielding closed-form results. Lévy laws are shown to universally emerge from the SFC model, and characterize both heavy tailed retention times (Noah effect) and long-ranged correlations (Joseph effect).

Lighting system with thermal management system

DOEpatents

Arik, Mehmet; Weaver, Stanton Earl; Stecher, Thomas Elliot; Seeley, Charles Erklin; Kuenzler, Glenn Howard; Wolfe, Jr., Charles Franklin; Utturkar, Yogen Vishwas; Sharma, Rajdeep; Prabhakaran, Satish; Icoz, Tunc

2015-02-24

Lighting systems having unique configurations are provided. For instance, the lighting system may include a light source, a thermal management system and driver electronics, each contained within a housing structure. The light source is configured to provide illumination visible through an opening in the housing structure. The thermal management system is configured to provide an air flow, such as a unidirectional air flow, through the housing structure in order to cool the light source. The driver electronics are configured to provide power to each of the light source and the thermal management system.

Lighting system with thermal management system

DOEpatents

Arik, Mehmet; Weaver, Stanton Earl; Stecher, Thomas Elliot; Seeley, Charles Erklin; Kuenzler, Glenn Howard; Wolfe, Jr., Charles Franklin; Utturkar, Yogen Vishwas; Sharma, Rajdeep; Prabhakaran, Satish; Icoz, Tunc

2015-08-25

Lighting systems having unique configurations are provided. For instance, the lighting system may include a light source, a thermal management system and driver electronics, each contained within a housing structure. The light source is configured to provide illumination visible through an opening in the housing structure. The thermal management system is configured to provide an air flow, such as a unidirectional air flow, through the housing structure in order to cool the light source. The driver electronics are configured to provide power to each of the light source and the thermal management system.

Lighting system with thermal management system

DOEpatents

Arik, Mehmet; Weaver, Stanton; Stecher, Thomas; Seeley, Charles; Kuenzler, Glenn; Wolfe, Jr., Charles; Utturkar, Yogen; Sharma, Rajdeep; Prabhakaran, Satish; Icoz, Tunc

2013-05-07

Lighting systems having unique configurations are provided. For instance, the lighting system may include a light source, a thermal management system and driver electronics, each contained within a housing structure. The light source is configured to provide illumination visible through an opening in the housing structure. The thermal management system is configured to provide an air flow, such as a unidirectional air flow, through the housing structure in order to cool the light source. The driver electronics are configured to provide power to each of the light source and the thermal management system.

Lighting system with thermal management system

DOEpatents

Arik, Mehmet; Weaver, Stanton Earl; Stecher, Thomas Elliot; Seeley, Charles Erklin; Kuenzler, Glenn Howard; Wolfe, Jr, Charles Franklin; Utturkar, Yogen Vishwas; Sharma, Rajdeep; Prabhakaran, Satish; Icoz, Tunc

2016-10-11

Lighting systems having unique configurations are provided. For instance, the lighting system may include a light source, a thermal management system and driver electronics, each contained within a housing structure. The light source is configured to provide illumination visible through an opening in the housing structure. The thermal management system is configured to provide an air flow, such as a unidirectional air flow, through the housing structure in order to cool the light source. The driver electronics are configured to provide power to each of the light source and the thermal management system.

Processing the Army’s Wartime Replacements: The Preferred CONUS Replacement Center Concept.

DTIC Science & Technology

1987-12-01

Replacement System. The first model, the macro model, was a network flow model which was used to analyze the flow of replacements from their source through...individual CRCs. Through the analysis of the macro model, recommendations were made on how the CRC system should be configured in terms of size, location

Rate dependent fractionation of sulfur isotopes in through-flowing systems

NASA Astrophysics Data System (ADS)

Giannetta, M.; Sanford, R. A.; Druhan, J. L.

2017-12-01

The fidelity of reactive transport models in quantifying microbial activity in the subsurface is often improved through the use stable isotopes. However, the accuracy of current predictions for microbially mediated isotope fractionations within open through-flowing systems typically depends on nutrient availability. This disparity arises from the common application of a single `effective' fractionation factor assigned to a given system, despite extensive evidence for variability in the fractionation factor between eutrophic environments and many naturally occurring, nutrient-limited environments. Here, we demonstrate a reactive transport model with the capacity to simulate a variable fractionation factor over a range of microbially mediated reduction rates and constrain the model with experimental data for nutrient limited conditions. Two coupled isotope-specific Monod rate laws for 32S and 34S, constructed to quantify microbial sulfate reduction and predict associated S isotope partitioning, were parameterized using a series of batch reactor experiments designed to minimize microbial growth. In the current study, we implement these parameterized isotope-specific rate laws within an open, through-flowing system to predict variable fractionation with distance as a function of sulfate reduction rate. These predictions are tested through a supporting laboratory experiment consisting of a flow-through column packed with homogenous porous media inoculated with the same species of sulfate reducing bacteria used in the previous batch reactors, Desulfovibrio vulgaris. The collective results of batch reactor and flow-through column experiments support a significant improvement for S isotope predictions in isotope-sensitive multi-component reactive transport models through treatment of rate-dependent fractionation. Such an update to the model will better equip reactive transport software for isotope informed characterization of microbial activity within energy and nutrient limited environments.

An Insidious Mode of Oxidative Degradation in a SiC-SiC Composite

NASA Technical Reports Server (NTRS)

Ogbuji, Linus U. J. T.

1997-01-01

The oxidative durability of a SiC-SiC composite with Hi-Nicalon fiber and BN interphase was investigated at 800 C (where pesting is known to occur in SiC-SiC composites) for exposure durations of up to 500 hours and in a variety of oxidant mixes and flow rates, ranging from quasi-stagnant room air, through slow flowing O2 containing 30-90% H2O, to the high-velocity flame of a burner rig. Degradation of the composite was determined from residual strength and fracture strain in post-exposure mechanical tests and correlated with microstructural evidence of damage to fiber and interphase. The severest degradation of composite behavior was found to occur in the bumer rig, and is shown to be connected with the high oxidant velocity and substantial moisture content, as well as a thin sublayer of carbon indicated to form between fiber and interphase during composite processing.

USE OF NETWORK MODELS FOR ESTIMATING EXPOSURE OF CONSUMERS TO CONTAMINANTS IN DRINKING WATER DISTRIBUTION SYSTEMS

EPA Science Inventory

The presence of contaminants in a drinking water distribution system can result in exposure of consumers to contaminated water. Whether the contaminants result from waterborne outbreaks that accidentally enter the system or through purposeful acts, the movement of the resulting ...

Plant uprooting by flow as a fatigue mechanical process

NASA Astrophysics Data System (ADS)

Perona, Paolo; Edmaier, Katharina; Crouzy, Benoît

2015-04-01

In river corridors, plant uprooting by flow mostly occurs as a delayed process where flow erosion first causes root exposure until residual anchoring balances hydrodynamic forces on the part of the plant that is exposed to the stream. Because a given plant exposure time to the action of the stream is needed before uprooting occurs (time-to-uprooting), this uprooting mechanism has been denominated Type II, in contrast to Type I, which mostly affect early stage seedlings and is rather instantaneous. In this work, we propose a stochastic framework that describes a (deterministic) mechanical fatigue process perturbed by a (stochastic) process noise, where collapse occurs after a given exposure time. We test the model using the experimental data of Edmaier (2014) and Edmaier et al. (submitted), who investigated vegetation uprooting by flow in the limit of low plant stem-to-sediment size ratio by inducing parallel riverbed erosion within an experimental flume. We first identify the proper timescale and lengthscale for rescaling the model. Then, we show that it describes well all the empirical cumulative distribution functions (cdf) of time-to-uprooting obtained under constant riverbed erosion rate and assuming additive gaussian process noise. By this mean, we explore the level of determinism and stochasticity affecting the time-to-uprooting for Avena sativa in relation to root anchoring and flow drag forces. We eventually ascribe the overall dynamics of the Type II uprooting mechanism to the memory of the plant-soil system that is stored by root anchoring, and discuss related implications thereof. References Edmaier, K., Uprooting mechansims of juvenile vegetation by flow erosion, Ph.D. thesis, EPFL, 2014. Edmaier, K., Crouzy, B. and P. Perona. Experimental characterization of vegetation uprooting by flow. J. of Geophys. Res. - Biogeosci., submitted

40 CFR 202.10 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... exhaust system gas flow so as to discharge the exhaust gas and acoustic energy to the atmosphere without passing through the entire length of the exhaust system, including all exhaust system sound attenuation... system means the system comprised of a combination of components which provides for enclosed flow of...

Synthesis, characterization and cytotoxic evaluation of chitosan nanoparticles: in vitro liver cancer model

NASA Astrophysics Data System (ADS)

Loutfy, Samah A.; Alam El-Din, Hanaa M.; Elberry, Mostafa H.; Allam, Nanis G.; Hasanin, M. T. M.; Abdellah, Ahmed M.

2016-09-01

To evaluate the cytotoxic effect of chitosan nanoparticles (CS-NPs) on an in vitro human liver cancer cell model (HepG2) and their possible application as a drug delivery system, we synthesized water-soluble CS-NPs, investigated their properties and extensively evaluated their cytotoxic activity on the cellular and molecular levels. A human liver cancer cell line was used as a model of human liver cancer. The CS-NPs were characterized using transmission electron microscopy, Fourier transform infrared spectroscopy, and zeta analysis. The cytotoxic effects of the CS-NPs on HepG2 cells were monitored by sulforhodamine B colorimetric assays for cytotoxicity screening and flow cytometric analysis. Molecular investigations including DNA fragmentation and the expression of some apoptotic genes on the transcriptional RNA level were conducted. Treatment of HepG2 with different concentrations of 150 nm diameter CS-NPs did not show alteration of cell morphology after 24 h of cell exposure. Also, when cells were treated with 100 μg ml-1 of CS-NPs, 12% of them were killed and IC50 reached 239 μg ml-1 after 48 h of cell exposure. Flow cytometry evaluation of the CS-NPs revealed mild accumulation in the G2/M phase followed by cellular DNA fragmentation after 48 h of cell exposure. Extensive evaluation of the cytotoxic effect of the CS-NPs showed messenger RNA (mRNA) apoptotic gene expression (p53, Bak, Caspase3) after 24 h of cell exposure with no expression of the mRNA of the caspase 3 gene after 48 h of cell exposure, suggesting the involvement of an intrinsic apoptotic caspase-independent pathway by increasing the exposure time of 100 μg ml-1 of the CS-NPs. The engineered CS-NPs were controlled to a 150 nm size and charges of 40 mV and a concentration of 100 μg ml-1 revealed a genotoxic effect on HepG2 after 48 h of cell exposure through intrinsic apoptotic caspase-independent mechanisms. Further quantitative analysis on the molecular and protein levels is still required to confirm the impact of chitosan size and time on genotoxic effect before reaching a final conclusion and starting its biomedical application.

Comparison of secondary organic aerosol formed with an aerosol flow reactor and environmental reaction chambers: effect of oxidant concentration, exposure time and seed particles on chemical composition and yield

NASA Astrophysics Data System (ADS)

Lambe, A. T.; Chhabra, P. S.; Onasch, T. B.; Brune, W. H.; Hunter, J. F.; Kroll, J. H.; Cummings, M. J.; Brogan, J. F.; Parmar, Y.; Worsnop, D. R.; Kolb, C. E.; Davidovits, P.

2014-12-01

We performed a systematic intercomparison study of the chemistry and yields of SOA generated from OH oxidation of a common set of gas-phase precursors in a Potential Aerosol Mass (PAM) continuous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH concentrations ranging from 2.0×108 to 2.2×1010 molec cm-3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH concentrations ranging from 2×106 to 2×107 molec cm-3 over exposure times of several hours. The OH concentration in the chamber experiments is close to that found in the atmosphere, but the integrated OH exposure in the flow reactor can simulate atmospheric exposure times of multiple days compared to chamber exposure times of only a day or so. A linear correlation analysis of the mass spectra (m=0.91-0.92, r2=0.93-0.94) and carbon oxidation state (m=1.1, r2=0.58) of SOA produced in the flow reactor and environmental chambers for OH exposures of approximately 1011 molec cm-3 s suggests that the composition of SOA produced in the flow reactor and chambers is the same within experimental accuracy as measured with an aerosol mass spectrometer. This similarity in turn suggests that both in the flow reactor and in chambers, SOA chemical composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors, rather than heterogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than measured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed particles are routinely used.

In-vitro evidence for efficacy of antimicrobial mouthrinses

PubMed Central

Pan, Pauline C.; Harper, Scott; Ricci-Nittel, Danette; Lux, Renate; Shi, Wenyuan

2010-01-01

SUMMARY Objectives The objective of this study was to compare the antimicrobial activity of commercially available antiseptic mouthrinses against saliva-derived plaque biofilms in static and flow-through biofilm systems in vitro. Methods Nine mouthrinses were tested in a recirculating flow-through biofilm model (RFTB) with viability assessment by ATP bioluminescence. In addition, five mouthrinses were evaluated in a batch chamber slide biofilm (BCSB) model, using live- dead staining and confocal laser scanning microscopy. Results In the RFTB model, essential oil (EO) and chlorhexidine (CHX)-containing rinses showed equivalent antimicrobial activity and were more effective than a range of cetyl pyridinium chloride (CPC1) formulations. In the BCSB model, twice-daily mouthrinse exposure demonstrated that the EO rinse was significantly more effective than rinses containing amine and stannous fluorides, a combination of CPC/CHX and CPC2. EO showed biofilm kill comparable to the CHX rinse. Conclusions The present studies have shown that mouthrinses vary significantly in their capability to kill plaque biofilm bacteria in BCSB and RFTB models. The EO mouthrinse demonstrated superior antiplaque biofilm activity to AFSF, CPC/CHX, and CPC rinses and comparable activity to CHX. The methods tested may be of value for the in-vitro screening of antiseptic rinses with different modes of antimicrobial action. PMID:20621239

Using an Emergency Department Syndromic Surveillance System to Evaluate Reporting of Potential Rabies Exposures, Illinois, 2013-2015.

PubMed

Bemis, Kelley; Frias, Mabel; Patel, Megan Toth; Christiansen, Demian

Mandatory reporting of potential rabies exposures and initiation of postexposure prophylaxis (PEP) allow local health authorities to monitor PEP administration for errors. Our objectives were to use an emergency department (ED) syndromic surveillance system to (1) estimate reporting compliance for exposure to rabies in suburban Cook County, Illinois, and (2) initiate interventions to improve reporting and reassess compliance. We queried ED records from 45 acute care hospitals in Cook County and surrounding areas from January 1, 2013, through June 30, 2015, for chief complaints or discharge diagnoses pertaining to rabies, PEP, or contact with a wild mammal (eg, bat, raccoon, skunk, fox, or coyote). We matched patients with ≥1 ED visit for potential rabies exposure to people with potential rabies exposure reported to the Cook County Department of Public Health. We considered nonmatches to have unreported exposures. We then initiated active surveillance in July 2015, disseminated education on reporting requirements in August and September 2015, and reassessed reporting completeness from July 2015 through February 2016. Of 248 patients with rabies-related ED visits from January 2013 through June 2015, 63 (25.4%) were reported. After interventions were implemented to increase reporting compliance, 53 of 98 (54.1%) patients with rabies-related ED visits from July 2015 through February 2016 were reported. Patients with ED visits for potential rabies exposure were twice as likely to be reported postintervention than preintervention (risk ratio = 2.1; 95% CI, 1.6-2.8). The volume of potential rabies exposure cases reported to the health department from July 2015 through February 2016 increased by 252% versus the previous year. Potential rabies exposures and PEP initiation are underreported in suburban Cook County. ED syndromic surveillance records can be used to estimate reporting compliance and conduct active surveillance.

77 FR 21670 - Acibenzolar-S-

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-11

.../Exposure Analysis Modeling System and Screening Concentration in Ground Water (SCI-GROW) models, the... Classification System (NAICS) codes have been provided to assist you and others in determining whether this... reliable information.'' This includes exposure through drinking water and in residential settings, but does...

75 FR 40745 - Cyazofamid; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-14

... Model/Exposure Analysis Modeling System (PRZM/EXAMS) model for surface water and the Screening... listed in this unit could also be affected. The North American Industrial Classification System (NAICS... there is reliable information.'' This includes exposure through drinking water and in residential...

Simultaneous blood flow and blood oxygenation measurements using a combination of diffuse speckle contrast analysis and near-infrared spectroscopy

NASA Astrophysics Data System (ADS)

Seong, Myeongsu; Phillips, Zephaniah; Mai, Phuong Minh; Yeo, Chaebeom; Song, Cheol; Lee, Kijoon; Kim, Jae Gwan

2016-02-01

A combined diffuse speckle contrast analysis (DSCA)-near-infrared spectroscopy (NIRS) system is proposed to simultaneously measure qualitative blood flow and blood oxygenation changes in human tissue. The system employs an optical switch to alternate two laser sources at two different wavelengths and a CCD camera to capture the speckle image. Therefore, an optical density can be measured from two wavelengths for NIRS measurements and a speckle contrast can be calculated for DSCA measurements. In order to validate the system, a flow phantom test and an arm occlusion protocol for arterial and venous occlusion were performed. Shorter exposure times (<1 ms) show a higher drop (between 50% and 66%) and recovery of 1/KS2 values after occlusion (approximately 150%), but longer exposure time (3 ms) shows more consistent hemodynamic changes. For four subjects, the 1/KS2 values dropped to an average of 82.1±4.0% during the occlusion period and the average recovery of 1/KS2 values after occlusion was 109.1±0.8%. There was also an approximately equivalent amplitude change in oxyhemoglobin (OHb) and deoxyhemoglobin (RHb) during arterial occlusion (max RHb=0.0085±0.0024 mM/DPF, min OHb=-0.0057±0.0044 mM/DPF). The sensitivity of the system makes it a suitable modality to observe qualitative hemodynamic trends during induced physiological changes.

Carbon disulfide exposure and neurotoxic sequelae among viscose rayon workers

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

Aaserud, O.; Hommeren, O.J.; Tvedt, B.

1990-01-01

In Norway's only viscose rayon plant, carbon disulfide (CS2) concentrations in ambient air usually were between 30 and 50 mg/m3 during the first 23 years of production. From 1970/1971 until the factory was closed in 1982, corresponding values were 10-25 mg/m3. Through all of these years, high peak exposures of CS2 and H2S occurred. In 1986, 16 of the 24 men still at work in 1982 and with at least 10 years' experience in the spinning room agreed to participate in this study. Clinical neurological examination demonstrated abnormalities in 15; neuropsychological tests showed impairments of probable organic origin in 14.more » Thirteen had cerebral atrophy demonstrated by cerebral computed tomography (CT). Electromyography (EMG) was abnormal in six, neurography in 11. Regional cerebral blood flow measurements indicated flow asymmetries in eight, whereas Doppler investigation of the extracranial carotid and vertebral arteries, electroencephalography (EEG), and evoked response investigations were mostly normal. Based on these results and the exposure data, a diagnosis of CS2-induced encephalopathy was reached in eight workers; another six had an encephalopathy in which CS2 exposure was regarded as a partial cause. Correspondingly, seven had a neuropathy probably caused by CS2 exposure alone; in three others, CS2 was found to be the partial cause of a neuropathy. This indicates that long-term, relatively moderate exposure to CS2 in association with high peak exposures to CS2 and H2S involves a substantial risk of developing neurotoxic disease.« less

Brief Exposure to Secondhand Smoke Reversibly Impairs Endothelial Vasodilatory Function

PubMed Central

2014-01-01

Introduction: We sought to determine the effects of brief exposures to low concentrations of tobacco secondhand smoke (SHS) on arterial flow-mediated dilation (FMD, a nitric oxide-dependent measure of vascular endothelial function), in a controlled animal model never before exposed to smoke. In humans, SHS exposure for 30min impairs FMD. It is important to gain a better understanding of the acute effects of exposure to SHS at low concentrations and for brief periods of time. Methods: We measured changes in FMD in rats exposed to a range of real-world levels of SHS for durations of 30min, 10min, 1min, and 4 breaths (roughly 15 s). Results: We observed a dose-response relationship between SHS particle concentration over 30min and post-exposure impairment of FMD, which was linear through the range typically encountered in smoky restaurants and then saturated at higher concentrations. One min of exposure to SHS at moderate concentrations was sufficient to impair FMD. Conclusions: Brief SHS exposure at real-world levels reversibly impairs FMD. Even 1min of SHS exposure can cause reduction of endothelial function. PMID:24302638

Granular flow through an aperture: influence of the packing fraction.

PubMed

Aguirre, M A; De Schant, R; Géminard, J-C

2014-07-01

For the last 50 years, the flow of a granular material through an aperture has been intensely studied in gravity-driven vertical systems (e.g., silos and hoppers). Nevertheless, in many industrial applications, grains are horizontally transported at constant velocity, lying on conveyor belts or floating on the surface of flowing liquids. Unlike fluid flows, that are controlled by the pressure, granular flow is not sensitive to the local pressure but rather to the local velocity of the grains at the outlet. We can also expect the flow rate to depend on the local density of the grains. Indeed, vertical systems are packed in dense configurations by gravity, but, in contrast, in horizontal systems the density can take a large range of values, potentially very small, which may significantly alter the flow rate. In the present article, we study, for different initial packing fractions, the discharge through an orifice of monodisperse grains driven at constant velocity by a horizontal conveyor belt. We report how, during the discharge, the packing fraction is modified by the presence of the outlet, and we analyze how changes in the packing fraction induce variations in the flow rate. We observe that variations of packing fraction do not affect the velocity of the grains at the outlet, and, therefore, we establish that flow-rate variations are directly related to changes in the packing fraction.

Granular flow through an aperture: Influence of the packing fraction

NASA Astrophysics Data System (ADS)

Aguirre, M. A.; De Schant, R.; Géminard, J.-C.

2014-07-01

For the last 50 years, the flow of a granular material through an aperture has been intensely studied in gravity-driven vertical systems (e.g., silos and hoppers). Nevertheless, in many industrial applications, grains are horizontally transported at constant velocity, lying on conveyor belts or floating on the surface of flowing liquids. Unlike fluid flows, that are controlled by the pressure, granular flow is not sensitive to the local pressure but rather to the local velocity of the grains at the outlet. We can also expect the flow rate to depend on the local density of the grains. Indeed, vertical systems are packed in dense configurations by gravity, but, in contrast, in horizontal systems the density can take a large range of values, potentially very small, which may significantly alter the flow rate. In the present article, we study, for different initial packing fractions, the discharge through an orifice of monodisperse grains driven at constant velocity by a horizontal conveyor belt. We report how, during the discharge, the packing fraction is modified by the presence of the outlet, and we analyze how changes in the packing fraction induce variations in the flow rate. We observe that variations of packing fraction do not affect the velocity of the grains at the outlet, and, therefore, we establish that flow-rate variations are directly related to changes in the packing fraction.

Fluidized bed heat treating system

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

Ripley, Edward B; Pfennigwerth, Glenn L

Systems for heat treating materials are presented. The systems typically involve a fluidized bed that contains granulated heat treating material. In some embodiments a fluid, such as an inert gas, is flowed through the granulated heat treating medium, which homogenizes the temperature of the heat treating medium. In some embodiments the fluid may be heated in a heating vessel and flowed into the process chamber where the fluid is then flowed through the granulated heat treating medium. In some embodiments the heat treating material may be liquid or granulated heat treating material and the heat treating material may be circulatedmore » through a heating vessel into a process chamber where the heat treating material contacts the material to be heat treated. Microwave energy may be used to provide the source of heat for heat treating systems.« less

Occupational radiation Exposure at Agreement State-Licensed Materials Facilities, 1997-2010

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

U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research

The purpose of this report is to examine occupational radiation exposures received under Agreement State licensees. As such, this report reflects the occupational radiation exposure data contained in the Radiation Exposure Information and Reporting System (REIRS) database, for 1997 through 2010, from Agreement State-licensed materials facilities.

Sample environment for in situ synchrotron XRD measurements for CO2 interaction with subsurface materials

NASA Astrophysics Data System (ADS)

Elbakhshwan, M.; Gill, S.; Weidner, R.; Ecker, L.

2017-12-01

Sequestration of CO2 in geological formations requires a deep understanding of its interaction with the cement-casing components in the depleted oil and gas wells. Portland cement is used to seal the wellbores; however it tends to interact with the CO2. Therefore it is critical to investigate the wellbore integrity over long term exposure to CO2. Studies showed that, CO2 leakage is due to the flow through the casing-cement microannulus, cement-cement fractures, or the cement-caprock interface. The objective of this work is to gain a better understanding of the dissolution process of the cement-casing in the CO2 flow channels alongside with the carbonation reactions at the interfaces using XRF, XANES and X-ray tomography techniques. In this study, a synthetic wellbore system, consisting of cement with an embedded rectangular length of steel casing that had grooves to accommodate fluid flow, was used to investigate the casing-cement microannulus through core-flood experiments. The objective of this work is to gain a better understanding of the dissolution process of the cement-casing in the CO2 flow channels alongside with the carbonation reactions at the interfaces using a sample environment designed and built for in situ X-ray diffraction in the National Synchrotron Light Source II (NSLS II). The formation of carbonate phases at cement -fluid and cement-steel/fluid interfaces will be monitored in real time. Samples may be exposed to super critical CO2 at pressures above 1100 psi and temperatures around 50°C. The reaction cell is built from hastealloy to provide corrosion resistance, while the experimental temperature and pressure are controlled with thermocouples and pressure vessel.

System and method for improving performance of a fluid sensor for an internal combustion engine

DOEpatents

Kubinski, David [Canton, MI; Zawacki, Garry [Livonia, MI

2009-03-03

A system and method for improving sensor performance of an on-board vehicle sensor, such as an exhaust gas sensor, while sensing a predetermined substance in a fluid flowing through a pipe include a structure for extending into the pipe and having at least one inlet for receiving fluid flowing through the pipe and at least one outlet generally opposite the at least one inlet, wherein the structure redirects substantially all fluid flowing from the at least one inlet to the sensor to provide a representative sample of the fluid to the sensor before returning the fluid through the at least one outlet.

Computer aided approximation of flow rate through systemic-pulmonary arterial shunts (SPAS).

PubMed

Vennemann, Peter; Montag, Michael; Peters, Franz; Merzkirch, Wolfgang

2012-02-22

The discrimination of flow rates through bronchial arteries that are affected by pathological SPAS today still happens solely qualitatively. A reproducible quantification of flow rates, however, would enable the comprehension of phenomena like the intensified shunt perfusion seen in cases of chronic inflammations or the characterization of SPAS that may cause cardiovascular problems. A computational program is developed, that allows the modeling of individual bronchial arteries on the basis of the information provided by angiography. Angiographic images are available from the standard clinical assessment of SPAS. The flow through continuous and geometrically measurable vessel segments and SPAS is given by the law of Hagen-Poiseuille. The discharge through healthy branches is calculated by means of allometric scaling laws. The simulation results are verified by flow experiments in artificial vessel networks made of glass and PE tubing. The experimental set-up mimics realistic, pulsating pressure and flow conditions. When applied to the artificial vessel networks, the model described herein provides results for the volumetric flow rate that differ from values measured in laboratory experiments by <6%. The computer model is also applied to real angiographic images. Due to inaccuracies during the deduction of the geometry and due to necessary simplifications of the model, we expect significant deviations between calculated and real flow rates in bronchial systems. Nevertheless, the presented method enables the physician to objectively estimate the order of magnitude of volumetric flow through individual SPAS fairly independently from his experience and without the need of measurements additional to the mandatory angiography.

Experimental proof of faster-is-slower in systems of frictional particles flowing through constrictions.

PubMed

Pastor, José M; Garcimartín, Angel; Gago, Paula A; Peralta, Juan P; Martín-Gómez, César; Ferrer, Luis M; Maza, Diego; Parisi, Daniel R; Pugnaloni, Luis A; Zuriguel, Iker

2015-12-01

The "faster-is-slower" (FIS) effect was first predicted by computer simulations of the egress of pedestrians through a narrow exit [D. Helbing, I. J. Farkas, and T. Vicsek, Nature (London) 407, 487 (2000)]. FIS refers to the finding that, under certain conditions, an excess of the individuals' vigor in the attempt to exit causes a decrease in the flow rate. In general, this effect is identified by the appearance of a minimum when plotting the total evacuation time of a crowd as a function of the pedestrian desired velocity. Here, we experimentally show that the FIS effect indeed occurs in three different systems of discrete particles flowing through a constriction: (a) humans evacuating a room, (b) a herd of sheep entering a barn, and (c) grains flowing out a 2D hopper over a vibrated incline. This finding suggests that FIS is a universal phenomenon for active matter passing through a narrowing.

Two-axis direct fluid shear stress sensor

NASA Technical Reports Server (NTRS)

Bajikar, Sateesh (Inventor); Scott, Michael A. (Inventor); Adcock, Edward E. (Inventor)

2011-01-01

A micro sized multi-axis semiconductor skin friction/wall shear stress induced by fluid flow. The sensor design includes a shear/strain transduction gimble connected to a force collecting plate located at the flow boundary surface. The shear force collecting plate is interconnected by an arm to offset the tortional hinges from the fluid flow. The arm is connected to the shear force collecting plate through dual axis torsional hinges with piezoresistive torsional strain gauges. These gauges are disposed on the tortional hinges and provide a voltage output indicative of applied shear stress acting on the force collection plate proximate the flow boundary surface. Offsetting the torsional hinges creates a force concentration and resolution structure that enables the generation of a large stress on the strain gauge from small shear stress, or small displacement of the collecting plate. The design also isolates the torsional sensors from exposure to the fluid flow.

Rapid Induction of Therapeutic Hypothermia Using Transnasal High Flow Dry Air

PubMed Central

Chava, Raghuram; Raghavan, Madhavan Srinivas; Halperin, Henry; Maqbool, Farhan; Geocadin, Romergryko; Quinones-Hinojosa, Alfredo; Kolandaivelu, Aravindan; Rosen, Benjamin A.

2017-01-01

Early induction of therapeutic hypothermia (TH) is recommended in out-of-hospital cardiac arrest (CA); however, currently no reliable methods exist to initiate cooling. We investigated the effect of high flow transnasal dry air on brain and body temperatures in adult porcine animals. Adult porcine animals (n = 23) under general anesthesia were subject to high flow of transnasal dry air. Mouth was kept open to create a unidirectional airflow, in through the nostrils and out through the mouth. Brain, internal jugular, and aortic temperatures were recorded. The effect of varying airflow rate and the air humidity (0% or 100%) on the temperature profiles were recorded. The degree of brain cooling was measured as the differential temperature from baseline. A 10-minute exposure of high flow dry air caused rapid cooling of brain and gradual cooling of the jugular and the aortic temperatures in all animals. The degree of brain cooling was flow dependent and significantly higher at higher airflow rates (0.8°C ± 0.3°C, 1.03°C ± 0.6°C, and 1.3°C ± 0.7°C for 20, 40, and 80 L, respectively, p < 0.05 for all comparisons). Air temperature had minimal effect on the brain cooling over 10 minutes with similar decrease in temperature at 4°C and 30°C. At a constant flow rate (40 LPM) and temperature, the degree of cooling over 10 minutes during dry air exposure was significantly higher compared to humid air (100% saturation) (1.22°C ± 0.35°C vs. 0.21°C ± 0.12°C, p < 0.001). High flow transnasal dry air causes flow dependent cooling of the brain and the core temperatures in intubated porcine animals. The mechanism of cooling appears to be evaporation of nasal mucus as cooling is mitigated by humidifying the air. This mechanism may be exploited to initiate TH in CA. PMID:27635468

Rapid Induction of Therapeutic Hypothermia Using Transnasal High Flow Dry Air.

PubMed

Chava, Raghuram; Zviman, Menekhem; Raghavan, Madhavan Srinivas; Halperin, Henry; Maqbool, Farhan; Geocadin, Romergryko; Quinones-Hinojosa, Alfredo; Kolandaivelu, Aravindan; Rosen, Benjamin A; Tandri, Harikrishna

2017-03-01

Early induction of therapeutic hypothermia (TH) is recommended in out-of-hospital cardiac arrest (CA); however, currently no reliable methods exist to initiate cooling. We investigated the effect of high flow transnasal dry air on brain and body temperatures in adult porcine animals. Adult porcine animals (n = 23) under general anesthesia were subject to high flow of transnasal dry air. Mouth was kept open to create a unidirectional airflow, in through the nostrils and out through the mouth. Brain, internal jugular, and aortic temperatures were recorded. The effect of varying airflow rate and the air humidity (0% or 100%) on the temperature profiles were recorded. The degree of brain cooling was measured as the differential temperature from baseline. A 10-minute exposure of high flow dry air caused rapid cooling of brain and gradual cooling of the jugular and the aortic temperatures in all animals. The degree of brain cooling was flow dependent and significantly higher at higher airflow rates (0.8°C ± 0.3°C, 1.03°C ± 0.6°C, and 1.3°C ± 0.7°C for 20, 40, and 80 L, respectively, p < 0.05 for all comparisons). Air temperature had minimal effect on the brain cooling over 10 minutes with similar decrease in temperature at 4°C and 30°C. At a constant flow rate (40 LPM) and temperature, the degree of cooling over 10 minutes during dry air exposure was significantly higher compared to humid air (100% saturation) (1.22°C ± 0.35°C vs. 0.21°C ± 0.12°C, p < 0.001). High flow transnasal dry air causes flow dependent cooling of the brain and the core temperatures in intubated porcine animals. The mechanism of cooling appears to be evaporation of nasal mucus as cooling is mitigated by humidifying the air. This mechanism may be exploited to initiate TH in CA.

MODELING AIR FLOW DYNAMICS IN RADON MITIGATION SYSTEMS: A SIMPLIFIED APPROACH

EPA Science Inventory

The paper refines and extends an earlier study--relating to the design of optimal radon mitigation systems based on subslab depressurization-- that suggested that subslab air flow induced by a central suction point be treated as radial air flow through a porous bed contained betw...

Personal cooling air filtering device

DOEpatents

Klett, James [Knoxville, TN; Conway, Bret [Denver, NC

2002-08-13

A temperature modification system for modifying the temperature of fluids includes at least one thermally conductive carbon foam element, the carbon foam element having at least one flow channel for the passage of fluids. At least one temperature modification device is provided, the temperature modification device thermally connected to the carbon foam element and adapted to modify the temperature of the carbon foam to modify the temperature of fluids flowing through the flow channels. Thermoelectric and/or thermoionic elements can preferably be used as the temperature modification device. A method for the reversible temperature modification of fluids includes the steps of providing a temperature modification system including at least one thermally conductive carbon foam element having flow channels and at least one temperature modification device, and flowing a fluid through the flow channels.

Effect of cabin ventilation rate on ultrafine particle exposure inside automobiles.

PubMed

Knibbs, Luke D; de Dear, Richard J; Morawska, Lidia

2010-05-01

We alternately measured on-road and in-vehicle ultrafine (<100 nm) particle (UFP) concentration for 5 passenger vehicles that comprised an age range of 18 years. A range of cabin ventilation settings were assessed during 301 trips through a 4 km road tunnel in Sydney, Australia. Outdoor air flow (ventilation) rates under these settings were quantified on open roads using tracer gas techniques. Significant variability in tunnel trip average median in-cabin/on-road (I/O) UFP ratios was observed (0.08 to approximately 1.0). Based on data spanning all test automobiles and ventilation settings, a positive linear relationship was found between outdoor air flow rate and I/O ratio, with the former accounting for a substantial proportion of variation in the latter (R(2) = 0.81). UFP concentrations recorded in-cabin during tunnel travel were significantly higher than those reported by comparable studies performed on open roadways. A simple mathematical model afforded the ability to predict tunnel trip average in-cabin UFP concentrations with good accuracy. Our data indicate that under certain conditions, in-cabin UFP exposures incurred during tunnel travel may contribute significantly to daily exposure. The UFP exposure of automobile occupants appears strongly related to their choice of ventilation setting and vehicle.

A mid-infrared flow-through sensor for label-free monitoring of enzyme inhibition.

PubMed

Armenta, S; Tomischko, W; Lendl, B

2008-12-01

Label-free monitoring of acetylcholinesterase (AChE) activity was achieved with a mid-infrared flow-through sensor. The flow-through sensor comprised agarose beads, carrying covalently immobilized AChE, which were placed in a temperature-controlled (37 degrees C) CaF(2) flow cell with an optical path of 60 mum. The sensor was incorporated into a computer-controlled sequential injection (SI) system for automated liquid handling. Different mixtures of enzyme substrate acetylcholine (ACh) and inhibitor (tacrine) were prepared and fed into the flow-through sensor. The flow was stopped as soon as the prepared mixtures reached the sensor. Enzymatic hydrolysis of ACh by AChE was directly monitored as it took place in the flow-through sensor. The inhibition effect of tacrine was calculated from the reaction-induced spectral changes, revealing an important decrease in the activity of AChE, approaching zero when the inhibitor concentration is high enough. The developed mid-infrared flow-through sensor is flexible and can be used to study the inhibitor activity of different target molecules as well as different enzymes.

76 FR 70890 - Fenamidone; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-16

.../models/water/index.htm . Based on the Pesticide Root Zone Model/Exposure Analysis Modeling System (PRZM... listed in this unit could also be affected. The North American Industrial Classification System (NAICS... there is reliable information.'' This includes exposure through drinking water and in residential...

Relationship between changes in the cochlear blood flow and disorder of hearing function induced by blast injury in guinea pigs.

PubMed

Chen, Wei; Wang, Jianmin; Chen, Jing; Chen, Jichuan; Chen, Zhiqiang

2013-01-01

The auditory system is the most susceptible to damages from blast waves. Blast injuries always lead to varying degrees of hearing impairment. Although a disorder of the cochlear blood flow (CoBF) has been considered to be related to many pathological processes of the auditory system and to contribute to various types of hearing loss, changes in the CoBF induced by blast waves and the relationship between such changes and hearing impairment are undefined. To observe the changes in the cochlear microcirculation after exposure to an explosion blast, investigate the relationship between changes in the CoBF and hearing impairment and subsequently explore the mechanism responsible for the changes in the CoBF, we detected the perfusion of the cochlear microcirculation and hearing threshold shift after exposure to an explosion blast. Then, an N-nitro-L-arginine-methyl ester (L-NAME, NO synthase inhibitor) solution and artificial perilymph were applied to the round window (RW) of the cochlea before the blast exposure, followed by an evaluation of the CoBF and hearing function. The results indicated that the changes in the CoBF were correlated to the strength of the blast wave. The cochlear blood flow significantly increased when the peak value of the blast overpressure was greater than approximately 45 kPa, and there was no significant change in the cochlear blood flow when the peak value of the blast overpressure was less than approximately 35 kPa. Following local administration of the NO synthase inhibitor L-NAME, the increase in the CoBF induced by the blast was inhibited, and this reduction was significantly associated with the hearing threshold.

Recolonization of laser-ablated bacterial biofilm.

PubMed

Nandakumar, Kanavillil; Obika, Hideki; Utsumi, Akihiro; Toshihiko, Ooie; Yano, Tetsuo

2004-01-20

The recolonization of laser-ablated bacterial monoculture biofilm was studied in the laboratory by using a flow-cytometer system. The marine biofilm-forming bacterium Pseudoalteromonas carrageenovora was used to develop biofilms on titanium coupons. Upon exposure to a low-power pulsed irradiation from an Nd:YAG laser, the coupons with biofilm were significantly reduced both in terms of total viable count (TVC) and area cover. The energy density used for a pulse of 5 ns was 0.1 J/cm(2) and the durations of irradiation exposure were 5 and 10 min. When placed in a flow of dilute ZoBell marine broth medium (10%) the laser-destructed bacterial film in a flow-cytometer showed significant recovery over a period of time. The flow of medium was regulated at 3.2 ml/min. The increase in area cover and TVC, however, was significantly less than that observed for nonirradiated control (t-test, P< 0.05). The coupons were observed for biofilm area cover and TVC at different intervals (3, 6, and 9 h) after irradiation. While the biofilm in the control coupon at the end of 9 h of exposure showed 95.6 +/- 4.1% cover, the 5- and 10-min irradiated samples after 9 h showed 60.3 +/- 6.5 and 37.4 +/- 12.1% area cover, respectively. The reduced rate of recolonization compared to control was thought be due to the lethal and sublethal impacts of laser irradiation on bacteria. This observation thus provided data on the online recolonization speed of biofilm, which is important when considering pulsed laser irradiation as an ablating technique of biofilm formation and removal in natural systems. Copyright 2003 Wiley Periodicals, Inc.

Experimental and modeling study of thermal exposure of a self-contained breathing apparatus (SCBA).

PubMed

Donnelly, Michelle K; Yang, Jiann C

2015-08-01

An experimental apparatus designed to study firefighter safety equipment exposed to a thermal environment was developed. The apparatus consisted of an elevated temperature flow loop with the ability to heat the air stream up to 200°C. The thermal and flow conditions at the test section were characterized using thermocouples and bi-directional probes. The safety equipment examined in this study was a self-contained breathing apparatus (SCBA), including a facepiece and an air cylinder. The SCBA facepiece was placed on a mannequin headform and coupled to a breathing simulator that was programmed with a prescribed breathing pattern. The entire SCBA assembly was placed in the test section of the flow loop for these thermal exposure experiments. Three air stream temperatures, 100°C, 150°C, and 200°C, were used with the average air speed at the test section set at 1.4m/s and thermal exposure durations up to 1200 s. Measurements were made using type-K bare-bead thermocouples located in the mannequin's mouth and on the outer surface of the SCBA cylinder. The experimental results indicated that increasing the thermal exposure severity and duration increased the breathing air temperatures supplied by the SCBA. Temperatures of breathing air from the SCBA cylinder in excess of 60°C were observed over the course of the thermal exposure conditions used in most of the experiments. A mathematical model for transient heat transfer was developed to complement the thermal exposure experimental study. The model took into consideration forced convective heat transfer, quasi-steady heat conduction through the composite layers of the SCBA cylinder wall, the breathing pattern and action of the breathing simulator, and predicted air temperatures from the thermally exposed SCBA cylinder and temperatures at the outer surface of the SCBA cylinder. Model predictions agreed reasonably well with the experimental measurements. Published by Elsevier Ltd.

Universal chemiluminescence flow-through device based on directed self-assembly of solid-state organic chromophores on layered double hydroxide matrix.

PubMed

Wang, Zhihua; Teng, Xu; Lu, Chao

2013-02-19

In this work, a universal chemiluminescence (CL) flow-through device suitable for various CL resonance energy transfer (CRET) systems has been successfully fabricated. Highly efficient CRET in solid-state photoactive organic molecules can be achieved by assembling them on the surface of layered double hydroxides (LDHs). We attribute these observations to the suppression of the intermolecular π-π stacking interactions among aromatic rings and the improvement of molecular orientation and planarity in the LDH matrix, enabling a remarkable increase in fluorescence lifetime and quantum yield of organic molecules. Under optimal conditions, using peroxynitrous acid-fluorescein dianion (FLUD) as a model CRET system, trace FLUD (10 μM) was assembled on the surface of LDHs. Peroxynitrous acid/nitrite could be assayed in the range of 1.0-500 μM, and the detection limit for peroxynitrous acid/nitrite (S/N = 3) was 0.6 μM. This CL flow-through device exhibited operational stability, high reproducibility, and long lifetime. While LDHs were immobilized in a flow-through device in the absence of FLUD, the detection limit for peroxynitrous acid/nitrite was 100 μM. On the other hand, FLUD at the same concentration can not enhance the CL intensity of peroxynitrous acid system. This fabricated CL flow-through column has been successfully applied to determine nitrite in sausage samples with recoveries of 98-102%. These satisfactory results demonstrated that our studies pave a novel way toward flow-through column-based CRET using solid-state organic molecules as acceptors for signal amplification.

Elimination of active species crossover in a room temperature, neutral pH, aqueous flow battery using a ceramic NaSICON membrane

NASA Astrophysics Data System (ADS)

Allcorn, Eric; Nagasubramanian, Ganesan; Pratt, Harry D.; Spoerke, Erik; Ingersoll, David

2018-02-01

Flow batteries are an attractive technology for energy storage of grid-scale renewables. However, performance issues related to ion-exchange membrane (IEM) fouling and crossover of species have limited the success of flow batteries. In this work we propose the use of the solid-state sodium-ion conductor NaSICON as an IEM to fully eliminate active species crossover in room temperature, aqueous, neutral pH flow batteries. We measure the room temperature conductivity of NaSICON at 2.83-4.67 mS cm-1 and demonstrate stability of NaSICON in an aqueous electrolyte with conductivity values remaining near 2.5 mS cm-1 after 66 days of exposure. Charge and discharge of a full H-cell battery as well as symmetric cycling in a flow battery configuration using NaSICON as an IEM in both cases demonstrates the capability of the solid-state IEM. Extensive analysis of aged cells through electrochemical impedance spectroscopy (EIS) and UV-vis spectroscopy show no contaminant species having crossed over the NaSICON membrane after 83 days of exposure, yielding an upper limit to the permeability of NaSICON of 4 × 10-10 cm2 min-1. The demonstration of NaSICON as an IEM enables a wide new range of chemistries for application to flow batteries that would previously be impeded by species crossover and associated degradation.

Elimination of active species crossover in a room temperature, neutral pH, aqueous flow battery using a ceramic NaSICON membrane

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

Allcorn, Eric; Nagasubramanian, Ganesan; Pratt, III, Harry D.

Flow batteries are an attractive technology for energy storage of grid-scale renewables. However, performance issues related to ion-exchange membrane (IEM) fouling and crossover of species have limited the success of flow batteries. In this work we propose the use of the solid-state sodium-ion conductor NaSICON as an IEM to fully eliminate active species crossover in room temperature, aqueous, neutral pH flow batteries. We measure the room temperature conductivity of NaSICON at 2.83–4.67 mS cm –1 and demonstrate stability of NaSICON in an aqueous electrolyte with conductivity values remaining near 2.5 mS cm –1 after 66 days of exposure. Charge andmore » discharge of a full H-cell battery as well as symmetric cycling in a flow battery configuration using NaSICON as an IEM in both cases demonstrates the capability of the solid-state IEM. Extensive analysis of aged cells through electrochemical impedance spectroscopy (EIS) and UV–vis spectroscopy show no contaminant species having crossed over the NaSICON membrane after 83 days of exposure, yielding an upper limit to the permeability of NaSICON of 4 × 10 –10 cm 2 min –1. As a result, the demonstration of NaSICON as an IEM enables a wide new range of chemistries for application to flow batteries that would previously be impeded by species crossover and associated degradation.« less

Elimination of active species crossover in a room temperature, neutral pH, aqueous flow battery using a ceramic NaSICON membrane

DOE PAGES

Allcorn, Eric; Nagasubramanian, Ganesan; Pratt, III, Harry D.; ...

2018-01-04

Flow batteries are an attractive technology for energy storage of grid-scale renewables. However, performance issues related to ion-exchange membrane (IEM) fouling and crossover of species have limited the success of flow batteries. In this work we propose the use of the solid-state sodium-ion conductor NaSICON as an IEM to fully eliminate active species crossover in room temperature, aqueous, neutral pH flow batteries. We measure the room temperature conductivity of NaSICON at 2.83–4.67 mS cm –1 and demonstrate stability of NaSICON in an aqueous electrolyte with conductivity values remaining near 2.5 mS cm –1 after 66 days of exposure. Charge andmore » discharge of a full H-cell battery as well as symmetric cycling in a flow battery configuration using NaSICON as an IEM in both cases demonstrates the capability of the solid-state IEM. Extensive analysis of aged cells through electrochemical impedance spectroscopy (EIS) and UV–vis spectroscopy show no contaminant species having crossed over the NaSICON membrane after 83 days of exposure, yielding an upper limit to the permeability of NaSICON of 4 × 10 –10 cm 2 min –1. As a result, the demonstration of NaSICON as an IEM enables a wide new range of chemistries for application to flow batteries that would previously be impeded by species crossover and associated degradation.« less

Extrapolation of systemic bioavailability assessing skin absorption and epidermal and hepatic metabolism of aromatic amine hair dyes in vitro

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

Manwaring, John, E-mail: manwaring.jd@pg.com; Rothe, Helga; Obringer, Cindy

Approaches to assess the role of absorption, metabolism and excretion of cosmetic ingredients that are based on the integration of different in vitro data are important for their safety assessment, specifically as it offers an opportunity to refine that safety assessment. In order to estimate systemic exposure (AUC) to aromatic amine hair dyes following typical product application conditions, skin penetration and epidermal and systemic metabolic conversion of the parent compound was assessed in human skin explants and human keratinocyte (HaCaT) and hepatocyte cultures. To estimate the amount of the aromatic amine that can reach the general circulation unchanged after passagemore » through the skin the following toxicokinetically relevant parameters were applied: a) Michaelis–Menten kinetics to quantify the epidermal metabolism; b) the estimated keratinocyte cell abundance in the viable epidermis; c) the skin penetration rate; d) the calculated Mean Residence Time in the viable epidermis; e) the viable epidermis thickness and f) the skin permeability coefficient. In a next step, in vitro hepatocyte K{sub m} and V{sub max} values and whole liver mass and cell abundance were used to calculate the scaled intrinsic clearance, which was combined with liver blood flow and fraction of compound unbound in the blood to give hepatic clearance. The systemic exposure in the general circulation (AUC) was extrapolated using internal dose and hepatic clearance, and C{sub max} was extrapolated (conservative overestimation) using internal dose and volume of distribution, indicating that appropriate toxicokinetic information can be generated based solely on in vitro data. For the hair dye, p-phenylenediamine, these data were found to be in the same order of magnitude as those published for human volunteers. - Highlights: • An entirely in silico/in vitro approach to predict in vivo exposure to dermally applied hair dyes • Skin penetration and epidermal conversion assessed in human skin explants and HaCaT • Systemic metabolism was modeled using hepatocyte cultures. • Toxicokinetically relevant parameters were applied to estimate systemic exposure. • There was a good agreement between in vitro and in vivo data.« less

Kinetics of Death of Bacterial Spores at Elevated Temperatures

PubMed Central

Wang, Daniel I-C.; Scharer, Jeno; Humphrey, Arthur E.

1964-01-01

The kinetics of death of Bacillus stearothermophilus spores (FS 7954) suspended in phosphate buffer (pH 7) were studied over a temperature range of 127.2 to 143.8 C and exposure times of 0.203 to 4.150 sec. These short exposure were achieved by use of a tubular flow reactor in which a suspension of spores was injected into a hot flowing stream at the entrance of the reactor. Thermal equilibria of the suspension with the hot stream was achieved within 0.0006 sec. After flow through a fixed length of reactor, the stream containing the spores was cooled by flash vaporization and then assayed for viable count. The death rate data were fitted by a logarithmic expression. However, logarithmic death rate was only approximated in the tail or high-kill regions of exposure. Death rate constants obtained from this portion of the data were found to correlate by Arrhenius as well as Absolute Reaction Rate Theory relationships. Thermal-death time curves were found to correlate the data rather poorly. The activation energy and frequency constant for an Arrhenius relationship fit of the data were found to be 83.6 kcal/gmole and 1047.2 min-1, respectively. The standard enthalpy and entropy changes for an Absolute Reaction Rate Theory relationship fit of the data were found to be 84.4 kcal/gmole and 157 cal/gmole-K, respectively. PMID:14215978

Advanced in Visualization of 3D Time-Dependent CFD Solutions

NASA Technical Reports Server (NTRS)

Lane, David A.; Lasinski, T. A. (Technical Monitor)

1995-01-01

Numerical simulations of complex 3D time-dependent (unsteady) flows are becoming increasingly feasible because of the progress in computing systems. Unfortunately, many existing flow visualization systems were developed for time-independent (steady) solutions and do not adequately depict solutions from unsteady flow simulations. Furthermore, most systems only handle one time step of the solutions individually and do not consider the time-dependent nature of the solutions. For example, instantaneous streamlines are computed by tracking the particles using one time step of the solution. However, for streaklines and timelines, particles need to be tracked through all time steps. Streaklines can reveal quite different information about the flow than those revealed by instantaneous streamlines. Comparisons of instantaneous streamlines with dynamic streaklines are shown. For a complex 3D flow simulation, it is common to generate a grid system with several millions of grid points and to have tens of thousands of time steps. The disk requirement for storing the flow data can easily be tens of gigabytes. Visualizing solutions of this magnitude is a challenging problem with today's computer hardware technology. Even interactive visualization of one time step of the flow data can be a problem for some existing flow visualization systems because of the size of the grid. Current approaches for visualizing complex 3D time-dependent CFD solutions are described. The flow visualization system developed at NASA Ames Research Center to compute time-dependent particle traces from unsteady CFD solutions is described. The system computes particle traces (streaklines) by integrating through the time steps. This system has been used by several NASA scientists to visualize their CFD time-dependent solutions. The flow visualization capabilities of this system are described, and visualization results are shown.

Impaired cerebral microcirculation induced by ammonium chloride in rats is due to cortical adenosine release.

PubMed

Bjerring, Peter Nissen; Bjerrum, Esben Jannik; Larsen, Fin Stolze

2018-06-01

Liver failure results in hyperammonaemia, impaired regulation of cerebral microcirculation, encephalopathy, and death. However, the key mediator that alters cerebral microcirculation remains unidentified. In this study we show that topically applied ammonium significantly increases periarteriolar adenosine tone on the brain surface of healthy rats and is associated with a disturbed microcirculation. Cranial windows were prepared in anaesthetized Wistar rats. The flow velocities were measured by speckle contrast imaging and compared before and after 30 min of exposure to 10 mM ammonium chloride applied on the brain surface. These flow velocities were compared with those for control groups exposed to artificial cerebrospinal fluid or ammonium plus an adenosine receptor antagonist. A flow preservation curve was obtained by analysis of flow responses to a haemorrhagic hypotensive challenge and during stepwise exsanguination. The periarteriolar adenosine concentration was measured with enzymatic biosensors inserted in the cortex. After ammonium exposure the arteriolar flow velocity increased by a median (interquartile range) of 21.7% (23.4%) vs. 7.2% (10.2%) in controls (n = 10 and n = 6, respectively, p <0.05), and the arteriolar surface area increased. There was a profound rise in the periarteriolar adenosine concentration. During the hypotensive challenge the flow decreased by 27.8% (14.9%) vs. 9.2% (14.9%) in controls (p <0.05). The lower limit of flow preservation remained unaffected, 27.7 (3.9) mmHg vs. 27.6 (6.4) mmHg, whereas the autoregulatory index increased, 0.29 (0.33) flow units per millimetre of mercury vs. 0.03 (0.21) flow units per millimetre of mercury (p <0.05). When ammonium exposure was combined with topical application of an adenosine receptor antagonist, the autoregulatory index was normalized. Vasodilation of the cerebral microcirculation during exposure to ammonium chloride is associated with an increase in the adenosine tone. Application of a specific adenosine receptor antagonist restores the regulation of the microcirculation. This indicates that adenosine could be a key mediator of the brain dysfunction seen during hyperammonaemia and is a potential therapeutic target. In patients with liver failure, disturbances in brain function are caused in part by ammonium toxicity. In our project we studied how ammonia, through adenosine release, affects the blood flow in the brain of rats. In our experimental model we demonstrated that the detrimental effect of ammonia on blood flow regulation was counteracted by blocking the adenosine receptors in the brain. With this observation we identified a novel potential treatment target. If we can confirm our findings in a future clinical study, this might help patients with liver failure and the severe condition called hepatic encephalopathy. Copyright © 2018 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Controlling allergens in animal rooms by using curtains.

PubMed

Krohn, Thomas C; Itter, Gabi; Fosse, Richard; Hansen, Axel K

2006-05-01

The reduction and control of allergens in the animal facility is important for staff working with laboratory animals. This study was designed to evaluate the efficiency of perforated Makrolon curtains in front of racks as a method to reduce the amount of allergen in the animal room. The experimental situation we studied provides some information regarding allergen disposition in animal rooms but is clearly artificial and does not reflect a typical, 'real-world' environment in terms of preventing exposure of workers to allergens. Plastic curtains with holes were placed in front of racks, and a corridor between the racks and a curtain was present. The room was ventilated with air, which was blown into the room through the middle of the corridor, flowing downstream and passing through the holes in the curtain. This set-up resulted in air flow from the corridor through the curtain. Air samples were collected from sites in the corridor and behind the curtain. The samples were analyzed for the allergen Mus m1, and the amount of allergen was calculated. The results show air flow from the aisle through the holes in the curtains and through the racks behind the curtains, and this flow keeps allergen behind the curtains and prevents its spread from the cages into the aisle. The present study shows that the use of curtains in front of the cage racks is an efficient way to prevent spread of allergens from rodent cages to the entire animal room.

Systems for column-based separations, methods of forming packed columns, and methods of purifying sample components

DOEpatents

Egorov, Oleg B.; O'Hara, Matthew J.; Grate, Jay W.; Chandler, Darrell P.; Brockman, Fred J.; Bruckner-Lea, Cynthia J.

2000-01-01

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Systems For Column-Based Separations, Methods Of Forming Packed Columns, And Methods Of Purifying Sample Components

DOEpatents

Egorov, Oleg B.; O'Hara, Matthew J.; Grate, Jay W.; Chandler, Darrell P.; Brockman, Fred J.; Bruckner-Lea, Cynthia J.

2006-02-21

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Systems For Column-Based Separations, Methods Of Forming Packed Columns, And Methods Of Purifying Sample Components.

DOEpatents

Egorov, Oleg B.; O'Hara, Matthew J.; Grate, Jay W.; Chandler, Darrell P.; Brockman, Fred J.; Bruckner-Lea, Cynthia J.

2004-08-24

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Flow through the nasal cavity of the spiny dogfish, Squalus acanthias

NASA Astrophysics Data System (ADS)

Timm-Davis, L. L.; Fish, F. E.

2015-12-01

The nasal cavity of spiny dogfish is a blind capsule with no internal connection to the oral cavity. Water is envisioned to flow through the cavity in a smooth, continuous flow pattern; however, this assumption is based on previous descriptions of the morphology of the olfactory cavity. No experimentation on the flow through the internal nasal cavity has been reported. Morphology of the head of the spiny dogfish ( Squalus acanthias) does not suggest a close external connection between the oral and nasal systems. However, dye visualization showed that there was flow through the nasal apparatus and from the excurrent nostril to the mouth when respiratory flows were simulated. The hydrodynamic flow through the nasal cavity was observed from flow tank experiments. The dorsum of the nasal cavity of shark heads from dead animals was exposed by dissection and a glass plate was glued over of the exposed cavity. When the head was placed in a flow, dye was observed to be drawn passively into the cavity showing a complex, three-dimensional hydrodynamic flow. Dye entered the incurrent nostril, flowed through the nasal lamellae, crossed over and under the nasal valve, and circulated around the nasal valve before exiting the excurrent nostril. When the nasal valve was removed, the dye became stagnant and back flowed out through the incurrent nostril. The single nasal valve has a hydrodynamic function that organizes a coherent flow of water through the cavity without disruption. The results suggest that the morphology of the nasal apparatus in concert with respiratory flow and ambient flows from active swimming can be used to draw water through the olfactory cavity of the shark.

Technology of forced flow and once-through boiling: A survey. [pressure distribution

NASA Technical Reports Server (NTRS)

Poppendieck, H. F.; Sabin, C. M.

1975-01-01

Representative boiling heat transfer and pressure drop information obtained primarily from past NASA and AEC programs is presented which is applicable to forced flow and once-through boiler systems. The forced convection boiler has a number of advantages: little possibility of flow mal-distribution; heat transfer characteristics are usually consistent; and conductances are predictable, so that higher heat fluxes may be employed with safety (which leads to more compact, lighter weight equipment). It was found that in gas-fired systems particularly, the controlling heat transfer resistance may be on the hot side, so that increased fluxes would require extended surfaces. If in a power generation system the working fluid is very expensive, a forced flow boiler can be designed especially for small holdup volume. If the fluid is temperature sensitive, the boiling side wall temperatures can be tailored to maintain maximum heat transfer rates without overheating the fluid. The forced flow and once-through configurations may be the only type which can satisfy a specific need (such as the automotive Rankine cycle power plant design having a very short time-response boiler).

Design and demonstration of a pumpless 14 compartment microphysiological system.

PubMed

Miller, Paula G; Shuler, Michael L

2016-10-01

We describe a human "Body-on-a-chip" device (or microphysiological system) that could be used to emulate drug distribution, metabolism, and action in the body. It is based upon a physiologically based pharmacokinetic-pharmacodynamic (PBPK-PD) model, where multiple chambers representing different organs are connected with fluidic channels to mimic multi-organ interactions within the body. Here we describe a pumpless 14 chamber (13 organs) microfluidic cell culture device that provides a separation between barrier and nonbarrier types of cell cultures. Our barrier chamber layer (skin, GI tract, and lung) allows for direct access and/or exposures to chemical or biological reagents forcing these reagents to pass through a barrier of cells established on a microfabricated membrane before exposing the nonbarrier tissue chambers (fat, kidney, heart, adrenal glands, liver, spleen, pancreas, bone marrow, brain, muscle) or entering the microfluidic circulation within the device. Our nonbarrier tissue chambers were created as three-dimensional configurations by resuspending cells in hydrogel (PGMatrix). We used cell lines to represent five of these organs (barrier lines-A549 [lung] and Caco2 [GI]) (nonbarrier lines-HepG2 C3A [liver], Meg01 [bone marrow], and HK2 [kidney]). The dimensions of our straight duct-like channels to each organ chamber were designed to provide the appropriate flow of a culture medium. The organ volumes and organ flow rates that have been reported for an average human male were used to estimate the desired fluid retention times in each organ chamber. The flow through the channels was induced by gravity on a custom programmed rocker platform which enabled pumpless operation and minimized bubble entrapment. The purpose of this paper is to describe the design and operation of a 14 chamber multi-organ system representing 13 tissues/organs with both barrier and nonbarrier tissue chambers and to study the interactive responses among the various cell lines. We demonstrate that five different cell lines survived with high viability (above 85%) for 7 days. We compared the individual observed flow rates to the compartments to the desired or estimated flow rates. This work demonstrates the feasibility of constructing, operating and maintaining a simple, gravity-driven, multi-organ microphysiological system with the capability of measuring cellular functions such as CYP1A1 and CYP3A4 activities, albumin release, urea, maintenance of tight junctions, and presence of surfactant for a sustained period. Biotechnol. Bioeng. 2016;113: 2213-2227. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Influence of vascular network design on gas transfer in lung assist device technology.

PubMed

Bassett, Erik K; Hoganson, David M; Lo, Justin H; Penson, Elliot J N; Vacanti, Joseph P

2011-01-01

Blood oxygenators are vital for the critically ill, but their use is limited to the hospital setting. A portable blood oxygenator or a lung assist device for ambulatory or long-term use would greatly benefit patients with chronic lung disease. In this work, a biomimetic blood oxygenator system was developed which consisted of a microfluidic vascular network covered by a gas permeable silicone membrane. This system was used to determine the influence of key microfluidic parameters-channel size, oxygen exposure length, and blood shear rate-on blood oxygenation and carbon dioxide removal. Total gas transfer increased linearly with flow rate, independent of channel size and oxygen exposure length. On average, CO(2) transfer was 4.3 times higher than oxygen transfer. Blood oxygen saturation was also found to depend on the flow rate per channel but in an inverse manner; oxygenation decreased and approached an asymptote as the flow rate per channel increased. These relationships can be used to optimize future biomimetic vascular networks for specific lung applications: gas transfer for carbon dioxide removal in patients with chronic obstructive pulmonary disease or oxygenation for premature infants requiring complete lung replacement therapy.

The effect of in vitro exposure to tributyltin on the immune competence of Chinook salmon (Oncorhynchus tshawytscha) leukocytes.

PubMed

Misumi, Ichiro; Yada, Takashi; Leong, Jo-Ann C; Schreck, Carl B

2009-02-01

We evaluated the direct effects of in vitro exposures to tributyltin (TBT), a widely used biocide, on the cell-mediated immune system of Chinook salmon (Oncorhynchus tshawytscha). Splenic and pronephric leukocytes isolated from juvenile Chinook salmon were exposed to TBT (0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6 mg/l) in cell cultures for 24 h. Effects of TBT on cell viability, induction of apoptosis, and mitogenic responses were measured by flow cytometry. Splenic and pronephric leukocytes in the presence of TBT experienced a concentration-dependent decrease in viability in cell cultures. Apoptosis was detected as one of the mechanisms of cell death after TBT exposure. In addition, pronephric lymphocytes exhibited a greater sensitivity to TBT exposure than pronephric granulocytes. The functional ability of splenic B-cells to undergo blastogenesis upon lipopolysaccharide stimulation was also significantly inhibited in the presence of 0.05, 0.07, or 0.10 mg/l of TBT in the cell cultures. Flow cytometric assay using a fluorescent conjugated monoclonal antibody against salmon surface immunoglobulin was employed for the conclusive identification of B-cells in the Chinook salmon leukocytes. Our findings suggest that adverse effects of TBT on the function or development of fish immune systems could lead to an increase in disease susceptibility and its subsequent ecological implications.

Atmospheric pressure flow reactor: Gas phase chemical kinetics under tropospheric conditions without wall effects

NASA Technical Reports Server (NTRS)

Koontz, Steven L. (Inventor); Davis, Dennis D. (Inventor)

1991-01-01

A flow reactor for simulating the interaction in the troposphere is set forth. A first reactant mixed with a carrier gas is delivered from a pump and flows through a duct having louvers therein. The louvers straighten out the flow, reduce turbulence and provide laminar flow discharge from the duct. A second reactant delivered from a source through a pump is input into the flowing stream, the second reactant being diffused through a plurality of small diffusion tubes to avoid disturbing the laminar flow. The commingled first and second reactants in the carrier gas are then directed along an elongated duct where the walls are spaced away from the flow of reactants to avoid wall interference, disturbance or turbulence arising from the walls. A probe connected with a measuring device can be inserted through various sampling ports in the second duct to complete measurements of the first and second reactants and the product of their reaction at selected XYZ locations relative to the flowing system.

Atlantic water flow through the Faroese Channels

NASA Astrophysics Data System (ADS)

Hansen, Bogi; Poulsen, Turið; Margretha Húsgarð Larsen, Karin; Hátún, Hjálmar; Østerhus, Svein; Darelius, Elin; Berx, Barbara; Quadfasel, Detlef; Jochumsen, Kerstin

2017-11-01

Through the Faroese Channels - the collective name for a system of channels linking the Faroe-Shetland Channel, Wyville Thomson Basin, and Faroe Bank Channel - there is a deep flow of cold waters from Arctic regions that exit the system as overflow through the Faroe Bank Channel and across the Wyville Thomson Ridge. The upper layers, in contrast, are dominated by warm, saline water masses from the southwest, termed Atlantic water. In spite of intensive research over more than a century, there are still open questions on the passage of these waters through the system with conflicting views in recent literature. Of special note is the suggestion that there is a flow of Atlantic water from the Faroe-Shetland Channel through the Faroe Bank Channel, which circles the Faroes over the slope region in a clockwise direction. Here, we combine the observational evidence from ship-borne hydrography, moored current measurements, surface drifter tracks, and satellite altimetry to address these questions and propose a general scheme for the Atlantic water flow through this channel system. We find no evidence for a continuous flow of Atlantic water from the Faroe-Shetland Channel to the Faroe Bank Channel over the Faroese slope. Rather, the southwestward-flowing water over the Faroese slope of the Faroe-Shetland Channel is totally recirculated within the combined area of the Faroe-Shetland Channel and Wyville Thomson Basin, except possibly for a small release in the form of eddies. This does not exclude a possible westward flow over the southern tip of the Faroe Shelf, but even including that, we estimate that the average volume transport of a Circum-Faroe Current does not exceed 0.5 Sv (1 Sv = 106 m3 s-1). Also, there seems to be a persistent flow of Atlantic water from the western part of the Faroe Bank Channel into the Faroe-Shetland Channel that joins the Slope Current over the Scottish slope. These conclusions will affect potential impacts from offshore activities in the region and they imply that recently published observational estimates of the transport of warm water towards the Arctic obtained by different methods are incompatible.

77 FR 10962 - Flazasulfuron; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-24

.../water/index.htm . Based on the Pesticide Root Zone Model/Exposure Analysis Modeling System (PRZM/EXAMS... Classification System (NAICS) codes have been provided to assist you and others in determining whether this... reliable information.'' This includes exposure through drinking water and in residential settings, but does...

Human and bovine viruses in the Milwaukee River Watershed: hydrologically relevant representation and relations with environmental variables

USGS Publications Warehouse

Corsi, Steven R.; Borchardt, M. A.; Spencer, S. K.; Hughes, Peter E.; Baldwin, Austin K.

2014-01-01

To examine the occurrence, hydrologic variability, and seasonal variability of human and bovine viruses in surface water, three stream locations were monitored in the Milwaukee River watershed in Wisconsin, USA, from February 2007 through June 2008. Monitoring sites included an urban subwatershed, a rural subwatershed, and the Milwaukee River at the mouth. To collect samples that characterize variability throughout changing hydrologic periods, a process control system was developed for unattended, large-volume (56–2800 L) filtration over extended durations. This system provided flow-weighted mean concentrations during runoff and extended (24-h) low-flow periods. Human viruses and bovine viruses were detected by real-time qPCR in 49% and 41% of samples (n = 63), respectively. All human viruses analyzed were detected at least once including adenovirus (40% of samples), GI norovirus (10%), enterovirus (8%), rotavirus (6%), GII norovirus (1.6%) and hepatitis A virus (1.6%). Three of seven bovine viruses analyzed were detected including bovine polyomavirus (32%), bovine rotavirus (19%), and bovine viral diarrhea virus type 1 (5%). Human viruses were present in 63% of runoff samples resulting from precipitation and snowmelt, and 20% of low-flow samples. Maximum human virus concentrations exceeded 300 genomic copies/L. Bovine viruses were present in 46% of runoff samples resulting from precipitation and snowmelt and 14% of low-flow samples. The maximum bovine virus concentration was 11 genomic copies/L. Statistical modeling indicated that stream flow, precipitation, and season explained the variability of human viruses in the watershed, and hydrologic condition (runoff event or low-flow) and season explained the variability of the sum of human and bovine viruses; however, no model was identified that could explain the variability of bovine viruses alone. Understanding the factors that affect virus fate and transport in rivers will aid watershed management for minimizing human exposure and disease transmission.

System and method for reducing combustion dynamics in a combustor

DOEpatents

Uhm, Jong Ho; Johnson, Thomas Edward; Zuo, Baifang; York, William David

2015-09-01

A system for reducing combustion dynamics in a combustor includes an end cap having an upstream surface axially separated from a downstream surface, and tube bundles extend from the upstream surface through the downstream surface. A divider inside a tube bundle defines a diluent passage that extends axially through the downstream surface, and a diluent supply in fluid communication with the divider provides diluent flow to the diluent passage. A method for reducing combustion dynamics in a combustor includes flowing a fuel through tube bundles, flowing a diluent through a diluent passage inside a tube bundle, wherein the diluent passage extends axially through at least a portion of the end cap into a combustion chamber, and forming a diluent barrier in the combustion chamber between the tube bundle and at least one other adjacent tube bundle.

[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.

Material handling robot system for flow-through storage applications

NASA Astrophysics Data System (ADS)

Dill, James F.; Candiloro, Brian; Downer, James; Wiesman, Richard; Fallin, Larry; Smith, Ron

1999-01-01

This paper describes the design, development and planned implementation of a system of mobile robots for use in flow through storage applications. The robots are being designed with on-board embedded controls so that they can perform their tasks as semi-autonomous workers distributed within a centrally controlled network. On the storage input side, boxes will be identified by bar-codes and placed into preassigned flow through bins. On the shipping side, orders will be forwarded to the robots from a central order processing station and boxes will be picked from designated storage bins following proper sequencing to permit direct loading into trucks for shipping. Because of the need to maintain high system availability, a distributed control strategy has been selected. When completed, the system will permit robots to be dynamically reassigned responsibilities if an individual unit fails. On-board health diagnostics and condition monitoring will be used to maintain high reliability of the units.

Trophic transfer potential of aluminium oxide nanoparticles using representative primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia).

PubMed

Pakrashi, Sunandan; Dalai, Swayamprava; Chandrasekaran, Natarajan; Mukherjee, Amitava

2014-07-01

The transfer of nanoparticles through the food chain can lead to bioaccumulation and biomagnification resulting in a long term negative impact on the ecosystem functions. The primary objective of this study was evaluation of aluminium oxide nanoparticles transfer from primary producers to primary consumers. A simple set up consisting of a primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia) was used. Here, C. ellipsoides were exposed to the varying concentrations of the nanoparticles ranging from 20 to 120μg/mL (196 to 1176μM) for 48h and the infested algal cells were used as the feed to C. dubia. The bioaccumulation of the nanoparticles into the daphnids was noted and the biomagnification factors were computed. The exposure was noted to cause subtle alterations in the feeding behaviour of the daphnids. This might have long term consequences in the energy flow through the food chain. The reproductive behaviour of the daphnids remained unaffected upon exposure to nanoparticle infested algal feed. Distinct observations at ultra-structural scale using transmission electron microscopy provided visual evidences for the disrupted feeding behaviour upon exposure to nanoparticle treated algae. Internalization of nanoparticle like inclusion bodies in the intracellular space of algae was also detected. The findings were further substantiated by a detailed analysis of hydrodynamic stability, bioavailability and dissolution of ions from the nanoparticles over the exposure period. Altogether, the study brings out the first of its kind of observation of trophic transfer potential/behaviour of aluminium oxide nanoparticles and its probable impacts on the energy flow in the fresh water aquatic ecosystem. Copyright © 2014 Elsevier B.V. All rights reserved.

Turnover Time

EPA Science Inventory

Ecosystems contain energy and materials such as carbon, nitrogen, phosphorus, and water, and are open to their flow-through. Turnover time refers to the amount of time required for replacement by flow-through of the energy or substance of interest contained in the system, and is ...

Triple loop heat exchanger for an absorption refrigeration system

DOEpatents

Reimann, Robert C.

1984-01-01

A triple loop heat exchanger for an absorption refrigeration system is disclosed. The triple loop heat exchanger comprises portions of a strong solution line for conducting relatively hot, strong solution from a generator to a solution heat exchanger of the absorption refrigeration system, conduit means for conducting relatively cool, weak solution from the solution heat exchanger to the generator, and a bypass system for conducting strong solution from the generator around the strong solution line and around the solution heat exchanger to an absorber of the refrigeration system when strong solution builds up in the generator to an undesirable level. The strong solution line and the conduit means are in heat exchange relationship with each other in the triple loop heat exchanger so that, during normal operation of the refrigeration system, heat is exchanged between the relatively hot, strong solution flowing through the strong solution line and the relatively cool, weak solution flowing through the conduit means. Also, the strong solution line and the bypass system are in heat exchange relationship in the triple loop heat exchanger so that if the normal flow path of relatively hot, strong solution flowing from the generator to an absorber is blocked, then this relatively, hot strong solution which will then be flowing through the bypass system in the triple loop heat exchanger, is brought into heat exchange relationship with any strong solution which may have solidified in the strong solution line in the triple loop heat exchanger to thereby aid in desolidifying any such solidified strong solution.

Development of a thermal-hydraulics experimental system for high Tc superconductors cooled by liquid hydrogen

NASA Astrophysics Data System (ADS)

Tatsumoto, H.; Shirai, Y.; Shiotsu, M.; Hata, K.; Kobayashi, H.; Naruo, Y.; Inatani, Y.; Kato, T.; Futakawa, M.; Kinoshita, K.

2010-06-01

A thermal-hydraulics experimental system of liquid hydrogen was developed in order to investigate the forced flow heat transfer characteristics in the various cooling channels for wide ranges of subcoolings, flow velocities, and pressures up to supercritical. A main tank is connected to a sub tank through a hydrogen transfer line with a control valve. A channel heater is located at one end of the transfer line in the main tank. Forced flow through the channel is produced by adjusting the pressure difference between the tanks and the valve opening. The mass flow rate is measured from the weight change of the main tank. For the explosion protection, electrical equipments are covered with a nitrogen gas blanket layer and a remote control system was established. The first cryogenic performance tests confirmed that the experimental system had satisfied with the required performances. The forced convection heat transfer characteristics was successfully measured at the pressure of 0.7 MPa for various flow velocities.

A novel methanol sensor based on gas-penetration through a porous polypyrrole-coated polyacrylonitrile nanofiber mat.

PubMed

Jun, Tae-Sun; Ho, Thi Anh; Rashid, Muhammad; Kim, Yong Shin

2013-09-01

In this work, we propose a novel chemoresistive gas sensor operated under a vertical analyte flow passing through a permeable sensing membrane. Such a configuration is different from the use of a planar sensor implemented under a conventional horizontal flow. A highly porous core-shell polyacrylonitrile-polypyrrole (PAN@PPy) nanofiber mat was prepared as the sensing element via electrospinning and two-step vapor-phase polymerization (VPP). Various analysis methods such as SEM, TEM, FT-IR and XPS measurements were employed in order to characterize structural features of the porous sensing mat. These analyses confirmed that very thin (ca. 10 nm) conductive PPy sheath layers were deposited by VPP on electrospun PAN nanofibers with an average diameter of 258 nm. Preliminary results revealed that the gas penetration-type PAN@PPy sensor had a higher sensor response and shorter detection and recovery times upon exposure to methanol analyte when compared with a conventional horizontal flow sensor due to efficient and fast analyte transfer into the sensing layer.

Upper Rio Grande water operations model: A tool for enhanced system management

Treesearch

Gail Stockton; D. Michael Roark

1999-01-01

The Upper Rio Grande Water Operations Model (URGWOM) under development through a multi-agency effort has demonstrated capability to represent the physical river/reservoir system, to track and account for Rio Grande flows and imported San Juan flows, and to forecast flows at various points in the system. Testing of the Rio Chama portion of the water operations model was...

The right wing of the LEFT airplane

NASA Technical Reports Server (NTRS)

Powell, Arthur G.

1987-01-01

The NASA Leading-Edge Flight Test (LEFT) program addressed the environmental issues which were potential problems in the application of Laminar Flow Control (LFC) to transport aircraft. These included contamination of the LFC surface due to dirt, rain, insect remains, snow, and ice, in the critical leading-edge region. Douglas Aircraft Company designed and built a test article which was mounted on the right wing of the C-140 JetStar aircraft. The test article featured a retractable leading-edge high-lift shield for contamination protection and suction through perforations on the upper surface for LFC. Following a period of developmental flight testing, the aircraft entered simulated airline service, which included exposure to airborne insects, heavy rain, snow, and icing conditions both in the air and on the ground. During the roughly 3 years of flight testing, the test article has consistently demonstrated laminar flow in cruising flight. The experience with the LEFT experiment was summarized with emphasis on significant test findings. The following items were discussed: test article design and features; suction distribution; instrumentation and transition point reckoning; problems and fixes; system performance and maintenance requirements.

The relationship of temperature rise to specific absorption rate and current in the human leg for exposure to electromagnetic radiation in the high frequency band.

PubMed

Wainwright, P R

2003-10-07

Of the biological effects of human exposure to radiofrequency and microwave radiation, the best-established are those due to elevation of tissue temperature. To prevent harmful levels of heating, restrictions have been proposed on the specific absorption rate (SAR). However, the relationship between SAR and temperature rise is not an invariant, since not only the heat capacity but also the efficiency of heat dissipation varies between different tissues and exposure scenarios. For small enough SAR, the relationship is linear and may be characterized by a 'heating factor' deltaT/SAR. Under whole-body irradiation the SAR may be particularly high in the ankles due to the concentration of current flowing through a relatively small cross-sectional area. In a previous paper, the author has presented calculations of the SAR distribution in a human leg in the high frequency (HF) band. In this paper, the heating factor for this situation is derived using a finite element approximation of the Pennes bioheat equation. The sensitivity of the results to different blood perfusion rates is investigated, and a simple local thermoregulatory model is applied. Both time-dependent and steady-state solutions are considered. Results confirm the appropriateness of the ICNIRP reference level of 100 mA on current through the leg, but suggest that at higher currents significant thermoregulatory adjustments to muscle blood flow will occur.

Code System to Calculate Tornado-Induced Flow Material Transport.

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

ANDRAE, R. W.

1999-11-18

Version: 00 TORAC models tornado-induced flows, pressures, and material transport within structures. Its use is directed toward nuclear fuel cycle facilities and their primary release pathway, the ventilation system. However, it is applicable to other structures and can model other airflow pathways within a facility. In a nuclear facility, this network system could include process cells, canyons, laboratory offices, corridors, and offgas systems. TORAC predicts flow through a network system that also includes ventilation system components such as filters, dampers, ducts, and blowers. These ventilation system components are connected to the rooms and corridors of the facility to form amore » complete network for moving air through the structure and, perhaps, maintaining pressure levels in certain areas. The material transport capability in TORAC is very basic and includes convection, depletion, entrainment, and filtration of material.« less

Effects of L-glutamine supplementation on maternal and fetal hemodynamics in gestating ewes exposed to alcohol

PubMed Central

Sawant, Onkar B.; Ramadoss, Jayanth; Hankins, Gary D.; Wu, Guoyao

2014-01-01

Not much is known about effects of gestational alcohol exposure on maternal and fetal cardiovascular adaptations. This study determined whether maternal binge alcohol exposure and L-glutamine supplementation could affect maternal-fetal hemodynamics and fetal regional brain blood flow during the brain growth spurt period. Pregnant sheep were randomly assigned to one of four groups: saline control, alcohol (1.75–2.5 g/kg body weight), glutamine (100 mg/kg body weight) or alcohol + glutamine. A chronic weekend binge drinking paradigm between gestational days (GD) 99 and 115 was utilized. Fetuses were surgically instrumented on GD 117 ± 1 and studied on GD 120 ± 1. Binge alcohol exposure caused maternal acidemia, hypercapnea, and hypoxemia. Fetuses were acidemic and hypercapnic, but not hypoxemic. Alcohol exposure increased fetal mean arterial pressure, whereas fetal heart rate was unaltered. Alcohol exposure resulted in ~40 % reduction in maternal uterine artery blood flow. Labeled microsphere analyses showed that alcohol induced >2-fold increases in fetal whole brain blood flow. The elevation in fetal brain blood flow was region-specific, particularly affecting the developing cerebellum, brain stem, and olfactory bulb. Maternal L-glutamine supplementation attenuated alcohol-induced maternal hypercapnea, fetal acidemia and increases in fetal brain blood flow. L-Glutamine supplementation did not affect uterine blood flow. Collectively, alcohol exposure alters maternal and fetal acid–base balance, decreases uterine blood flow, and alters fetal regional brain blood flow. Importantly, L-glutamine supplementation mitigates alcohol-induced acid–base imbalances and alterations in fetal regional brain blood flow. Further studies are warranted to elucidate mechanisms responsible for alcohol-induced programming of maternal uterine artery and fetal circulation adaptations in pregnancy. PMID:24810329

Effects of L-glutamine supplementation on maternal and fetal hemodynamics in gestating ewes exposed to alcohol.

PubMed

Sawant, Onkar B; Ramadoss, Jayanth; Hankins, Gary D; Wu, Guoyao; Washburn, Shannon E

2014-08-01

Not much is known about effects of gestational alcohol exposure on maternal and fetal cardiovascular adaptations. This study determined whether maternal binge alcohol exposure and L-glutamine supplementation could affect maternal-fetal hemodynamics and fetal regional brain blood flow during the brain growth spurt period. Pregnant sheep were randomly assigned to one of four groups: saline control, alcohol (1.75-2.5 g/kg body weight), glutamine (100 mg/kg body weight) or alcohol + glutamine. A chronic weekend binge drinking paradigm between gestational days (GD) 99 and 115 was utilized. Fetuses were surgically instrumented on GD 117 ± 1 and studied on GD 120 ± 1. Binge alcohol exposure caused maternal acidemia, hypercapnea, and hypoxemia. Fetuses were acidemic and hypercapnic, but not hypoxemic. Alcohol exposure increased fetal mean arterial pressure, whereas fetal heart rate was unaltered. Alcohol exposure resulted in ~40 % reduction in maternal uterine artery blood flow. Labeled microsphere analyses showed that alcohol induced >2-fold increases in fetal whole brain blood flow. The elevation in fetal brain blood flow was region-specific, particularly affecting the developing cerebellum, brain stem, and olfactory bulb. Maternal L-glutamine supplementation attenuated alcohol-induced maternal hypercapnea, fetal acidemia and increases in fetal brain blood flow. L-Glutamine supplementation did not affect uterine blood flow. Collectively, alcohol exposure alters maternal and fetal acid-base balance, decreases uterine blood flow, and alters fetal regional brain blood flow. Importantly, L-glutamine supplementation mitigates alcohol-induced acid-base imbalances and alterations in fetal regional brain blood flow. Further studies are warranted to elucidate mechanisms responsible for alcohol-induced programming of maternal uterine artery and fetal circulation adaptations in pregnancy.

Effects of chronic pollution and water flow intermittency on stream biofilms biodegradation capacity.

PubMed

Rožman, Marko; Acuña, Vicenç; Petrović, Mira

2018-02-01

A mesocosm case study was conducted to gain understanding and practical knowledge on biofilm emerging contaminants biodegradation capacity under stressor and multiple stressor conditions. Two real life scenarios: I) biodegradation in a pristine intermittent stream experiencing acute pollution and II) biodegradation in a chronically polluted intermittent stream, were examined via a multifactorial experiment using an artificial stream facility. Stream biofilms were exposed to different water flow conditions i.e. permanent and intermittent water flow. Venlafaxine, a readily biodegradable pharmaceutical was used as a measure of biodegradation capacity while pollution was simulated by a mixture of four emerging contaminants (erythromycin, sulfisoxazole, diclofenac and imidacloprid in addition to venlafaxine) in environmentally relevant concentrations. Biodegradation kinetics monitored via LC-MS/MS was established, statistically evaluated, and used to link biodegradation with stress events. The results suggest that the effects of intermittent flow do not hinder and may even stimulate pristine biofilm biodegradation capacity. Chronic pollution completely reduced biodegradation in permanent water flow experimental treatments while no change in intermittent streams was observed. A combined effect of water flow conditions and emerging contaminants exposure on biodegradation was found. The decrease in biodegradation due to exposure to emerging contaminants is significantly greater in streams with permanent water flow suggesting that the short and medium term biodegradation capacity in intermittent systems may be preserved or even greater than in perennial streams. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatial distribution of damage around faults in the Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah: A mechanical analog for faulting in pyroclastic deposits on Mars

USGS Publications Warehouse

Okubo, Chris H.

2012-01-01

Volcanic ash is thought to comprise a large fraction of the Martian equatorial layered deposits and much new insight into the process of faulting and related fluid flow in these deposits can be gained through the study of analogous terrestrial tuffs. This study identifies a set of fault-related processes that are pertinent to understanding the evolution of fault systems in fine-grained, poorly indurated volcanic ash by investigating exposures of faults in the Miocene-aged Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah. The porosity and granularity of the host rock are found to control the style of localized strain that occurs prior to and contemporaneous with faulting. Deformation bands occur in tuff that was porous and granular at the time of deformation, while fractures formed where the tuff lost its porous and granular nature due to silicic alteration. Non-localized deformation of the host rock is also prominent and occurs through compaction of void space, including crushing of pumice clasts. Significant off-fault damage of the host rock, resembling fault pulverization, is recognized adjacent to one analog fault and may reflect the strain rate dependence of the resulting fault zone architecture. These findings provide important new guidelines for future structural analyses and numerical modeling of faulting and subsurface fluid flow through volcanic ash deposits on Mars.

Extracting uranium from seawater: Promising AI series adsorbents

DOE PAGES

Das, Sadananda; Oyola, Y.; Mayes, Richard T.; ...

2015-11-10

A series of adsorbent (AI10 through AI17) were successfully developed at ORNL by radiation induced graft polymerization (RIGP) of acrylonitrile (AN) and vinylphosphonic acid (VPA) (at different mole/mole ratios) onto high surface area polyethylene fiber, with higher degree of grafting which ranges from 110 300%. The grafted nitrile groups were converted to amidoxime groups by reaction with 10 wt% hydroxylamine at 80 C for 72 hours. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8 ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged frommore » 171-187 g-U/kg-ads irrespective of %DOG. The performance of the adsorbents for uranium adsorption in natural seawater was also carried out using flow-through-column at Pacific Northwest National Laboratory (PNNL). The three hours KOH conditioning was better for higher uranium uptake than one hour. The adsorbent AI11 containing AN and VPA at the mole ration of 3.52, emerged as the potential candidate for higher uranium adsorption (3.35 g-U/Kg-ads.) after 56 days of exposure in the seawater in the flow-through-column. The rate vanadium adsorption over uranium was linearly increased throughout the 56 days exposure. The total vanadium uptake was ~5 times over uranium after 56 days.« less

Extracting uranium from seawater: Promising AI series adsorbents

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

Das, Sadananda; Oyola, Y.; Mayes, Richard T.

A series of adsorbent (AI10 through AI17) were successfully developed at ORNL by radiation induced graft polymerization (RIGP) of acrylonitrile (AN) and vinylphosphonic acid (VPA) (at different mole/mole ratios) onto high surface area polyethylene fiber, with higher degree of grafting which ranges from 110 300%. The grafted nitrile groups were converted to amidoxime groups by reaction with 10 wt% hydroxylamine at 80 C for 72 hours. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8 ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged frommore » 171-187 g-U/kg-ads irrespective of %DOG. The performance of the adsorbents for uranium adsorption in natural seawater was also carried out using flow-through-column at Pacific Northwest National Laboratory (PNNL). The three hours KOH conditioning was better for higher uranium uptake than one hour. The adsorbent AI11 containing AN and VPA at the mole ration of 3.52, emerged as the potential candidate for higher uranium adsorption (3.35 g-U/Kg-ads.) after 56 days of exposure in the seawater in the flow-through-column. The rate vanadium adsorption over uranium was linearly increased throughout the 56 days exposure. The total vanadium uptake was ~5 times over uranium after 56 days.« less

Tributyltin and triphenyltin induce spermatogenesis in ovary of female abalone, Haliotis gigantea.

PubMed

Horiguchi, T; Kojima, M; Kaya, M; Matsuo, T; Shiraishi, H; Morita, M; Adachi, Y

2002-01-01

Two-month flow-through exposure experiments of tributyltin (TBT) and triphenyltin (TPhT) were conducted with abalone, Haliotis gigantea. Nominal concentrations of 100 ng TBT/l and 100 ng TPhT/l caused significant spermatogenesis in ovaries of exposed females. There were also significantly more contracted primary oocytes observed in females exposed to either TBT or TPhT than controls. The incidence of two types of unknown cells was also significant in females exposed to TPhT. No significant histological changes were observed in testis of exposed males. This ovarian spermatogenesis caused by TBT and/or TPhT resembles gastropod imposex. Remarkably high concentrations of TBT and TPhT were observed in the head (including central nervous system ganglia), compared to muscles concentrations. Accumulation of TBT and TPhT in the head may disturb reproductive hormonal regulators through neuropeptides released from ganglia. This, as well as possible aromatase inhibition, may be one of the inducers for spermatogenesis in the abalone ovaries.

Impairment of the reproductive potential of male fathead minnows by environmentally relevant exposures to 4-nonylphenolf

USGS Publications Warehouse

Schoenfuss, H.L.; Bartell, S.E.; Bistodeau, T.B.; Cediel, R.A.; Grove, K.J.; Zintek, Larry; Lee, K.E.; Barber, L.B.

2008-01-01

The synthetic organic compound 4-nonylphenol (NP) has been detected in many human-impacted surface waters in North America. In this study, we examined the ability of NP to alter reproductive competence in male fathead minnows after a 28 day flow-through exposure in a range of environmentally relevant concentrations bracketing the U.S. Environmental Protection Agency toxicity-based NP chronic exposure criterion of 6.1 ??g NP/L. Exposure to NP at and above the EPA chronic exposure criterion resulted in an induction of plasma vitellogenin (VTG) within 14 days. However, 7 days after the cessation of exposure, VTG concentrations had dropped more than 50% and few males expressed VTG above the detection threshold. All of the morphological endpoints, including gonadosomatic index, hepatosomatic index, secondary sexual characters, and histopathology, were unaltered by all NP treatments. However, when NP-exposed male fish were allowed to compete with control males for access to nest sites and females, most treatments altered the reproductive competence of exposed males. At lower NP concentrations, exposed males out-competed control males, possibly by being primed through the estrogenic NP exposure in a fashion similar to priming by pheromones released from female fathead minnows. At higher NP exposure concentrations, this priming effect was negated by the adverse effects of the exposure and control males out-competed treated males. Results of this study indicate the complexity of endocrine disrupting effects and the need for multiple analysis levels to assess the effects of these compounds on aquatic organisms. ?? 2007 Elsevier B.V. All rights reserved.

Modeling hospital surgical delivery process design using system simulation: optimizing patient flow and bed capacity as an illustration.

PubMed

Kumar, Sameer

2011-01-01

It is increasingly recognized that hospital operation is an intricate system with limited resources and many interacting sources of both positive and negative feedback. The purpose of this study is to design a surgical delivery process in a county hospital in the U.S where patient flow through a surgical ward is optimized. The system simulation modeling is used to address questions of capacity planning, throughput management and interacting resources which constitute the constantly changing complexity that characterizes designing a contemporary surgical delivery process in a hospital. The steps in building a system simulation model is demonstrated using an example of building a county hospital in a small city in the US. It is used to illustrate a modular system simulation modeling of patient surgery process flows. The system simulation model development will enable planners and designers how they can build in overall efficiencies in a healthcare facility through optimal bed capacity for peak patient flow of emergency and routine patients.

AUGMENTATION OF MUSCLE BLOOD FLOW BY ULTRASOUND CAVITATION IS MEDIATED BY ATP AND PURINERGIC SIGNALING

PubMed Central

Belcik, J. Todd; Davidson, Brian P.; Xie, Aris; Wu, Melinda D.; Yadava, Mrinal; Qi, Yue; Liang, Sherry; Chon, Chae Ryung; Ammi, Azzdine Y.; Field, Joshua; Harmann, Leanne; Chilian, William M.; Linden, Joel; Lindner, Jonathan R.

2017-01-01

Background Augmentation of tissue blood flow by therapeutic ultrasound is thought to rely on convective shear. Microbubble contrast agents that undergo ultrasound-mediated cavitation markedly amplify these effects. We hypothesized that purinergic signalling is responsible for shear-dependent increases in muscle perfusion during therapeutic cavitation. Methods Unilateral exposure of the proximal hindlimb of mice (with or without ischemia produced by iliac ligation) to therapeutic ultrasound (1.3 MHz, mechanical index 1.3) was performed for ten minutes after intravenous injection of 2×108 lipid microbubbles. Microvascular perfusion was evaluated by low-power contrast ultrasound perfusion imaging. In vivo muscle ATP release and in vitro ATP release from endothelial cells or erythrocytes were assessed by a luciferin-luciferase assay. Purinergic signalling pathways were assessed by studying interventions that either (1) accelerated ATP degradation; (2) inhibited P2Y receptors, adenosine receptors, or KATP channels; or (3) inhibited downstream signalling pathways involving endothelial nitric oxide synthase (eNOS) or prostanoid production (indomethacin). Augmentation in muscle perfusion by ultrasound cavitation was assessed in a proof-of-concept clinical trial in 12 subjects with stable sickle cell disease (SCD). Results Therapeutic ultrasound cavitation increased muscle perfusion by 7-fold in normal mice, reversed tissue ischemia for up to 24 hrs in the murine model of peripheral artery disease, and doubled muscle perfusion in patients with SCD. Augmentation in flow extended well beyond the region of ultrasound exposure. Ultrasound cavitation produced a nearly 40-fold focal and sustained increase in ATP, the source of which included both endothelial cells and erythrocytes. Inhibitory studies indicated that ATP was a critical mediator of flow augmentation that acts primarily through either P2Y receptors or through adenosine produced by ectonucleotidase activity. Combined indomethacin and inhibition of eNOS abolished the effects of therapeutic ultrasound, indicating downstream signalling through both NO and prostaglandins. Conclusions Therapeutic ultrasound using microbubble cavitation to increase muscle perfusion relies on shear-dependent increases in ATP which can act through a diverse portfolio of purinergic signalling pathways. These events can reverse hindlimb ischemia in mice for >24 hours, and increase muscle blood flow in patients with sickle cell disease. Clinical Trial Registration NCT01566890 (https://clinicaltrials.gov/ct2/show/NCT01566890) PMID:28174191

77 FR 4248 - Cyazofamid; Pesticide Tolerances for Emergency Exemptions

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-27

.../water/index.htm . Based on the Pesticide Root Zone Model/Exposure Analysis Modeling System (PRZM/EXAMS... Classification System (NAICS) codes have been provided to assist you and others in determining whether this... reliable information.'' This includes exposure through drinking water and in residential settings, but does...

System and method for reducing combustion dynamics in a combustor

DOEpatents

Uhm, Jong Ho; Ziminsky, Willy Steve; Johnson, Thomas Edward; Srinivasan, Shiva; York, William David

2016-11-29

A system for reducing combustion dynamics in a combustor includes an end cap that extends radially across the combustor and includes an upstream surface axially separated from a downstream surface. A combustion chamber is downstream of the end cap, and tubes extend from the upstream surface through the downstream surface. Each tube provides fluid communication through the end cap to the combustion chamber. The system further includes means for reducing combustion dynamics in the combustor. A method for reducing combustion dynamics in a combustor includes flowing a working fluid through tubes that extend axially through an end cap that extends radially across the combustor and obstructing at least a portion of the working fluid flowing through a first set of the tubes.

Experimental exposure to methylformate and its neurobehavioral effects.

PubMed

Sethre, T; Läubli, T; Berode, M; Hangartner, M; Krueger, H

2000-08-01

The aim of the study was to investigate the acute effects of experimental methylformate exposure on the nervous system. In an exposure chamber, 20 subjects were exposed to methylformate at 100 ppm [Swiss maximum allowable concentration (MAC)] for 8 h. The same number of subjects with the same ages (between 20 and 30 years), gender and education level (university) were examined by the same procedure as a control group. The subjects did not know if they were exposed or not. Three times (morning, noon, evening) during these 8 h, mood [Profile of Mood States (POMS)], neurobehavioral performance (reaction, Stroop, nonverbal learning, determination, tracking; Wiener Test System), vision (visual acuity, contrast sensitivity, color sensitivity) and postural sway were tested. During an undemanding test (POMS) and a demanding performance task (determination test), pulse, electromyography (EMG) of the forehead and of the neck were recorded. In the morning and evening spirometry [forced vital capacity (FVC), forced one-second expiration volume (FEV), medium expiration flow (MEF) and peak expiration flow (PEF)] and the odor perception threshold were measured. In the evening, in the exposed group, fatigue was significantly increased and the EMG of the forehead during a demanding task showed a different development during exposure. The other tests showed no significant solvent effect, but 16 of 43 test parameters showed a significant effect of time. The results of this study indicate a possible effect of methylformate exposure on the subjective feeling of fatigue after 8 h exposure at 100 ppm in young and healthy subjects, without measurable impairment of neurobehavioral performance. We assume that a similar effect in normal work, combined with a heavy workload and shift work, can lead to an impairment of productivity, and increase the risk of accidents.

Local exhaust ventilation for the control of welding fumes in the construction industry--a literature review.

PubMed

Flynn, Michael R; Susi, Pam

2012-08-01

Arc welding is a common unit operation in the construction industry, where frequent changes in location and welding position make it more difficult to control fume exposures than in industries where fixed locations are the norm. Welders may be exposed to a variety of toxic airborne contaminants including manganese (Mn) and hexavalent chromium (CrVI). Local exhaust ventilation (LEV) is a well-known engineering control for welding fumes but has not been adopted widely in the construction industry. This literature review presents data on the performance of a variety of LEV systems for welding fume control from the construction (five references), shipyard (five references), and other industries. The studies indicate that LEV can reduce fume exposures to total particulate, Mn, and CrVI to levels below currently relevant standards. Field studies suggest that 40-50% or more reduction in exposure is possible with portable or fixed LEV systems relative to natural ventilation but that correct positioning of the hood and adequate exhaust flow rates are essential. Successful implementation of extraction guns for gas metal arc welding (GMAW) and flux core arc welding has been demonstrated, indicating that a successful balance between extraction airflow and shielding gas requirements is possible. Work practices are an important part of achieving successful control of fume exposures; in particular, positioning the hood close to the arc, checking exhaust flow rates, and avoiding the plume. Further research is needed on hood size effects for controlling welding fume with portable LEV systems and identifying and overcoming barriers to LEV use in construction.

Principles of Sociology in Systems Engineering

NASA Technical Reports Server (NTRS)

Watson, Michael D.; Andrews, James G.; Larsen, Jordan A.

2017-01-01

Systems engineering involves both the integration of the system and the integration of the disciplines which develop and operate the system. Integrating the disciplines is a sociological effort to bring together different groups, often with different terminology, to achieve a common goal, the system. The focus for the systems engineer is information flow through the organization, between the disciplines, to ensure the system is developed and operated with all relevant information informing system decisions. Robert K. Merton studied the sociological principles of the sciences and the sociological principles he developed apply to systems engineering. Concepts such as specification of ignorance, common terminology, opportunity structures, role-sets, and the reclama (reconsideration) process are all important sociological approaches that should be employed by the systems engineer. In bringing the disciplines together, the systems engineer must also be wary of social ambivalence, social anomie, social dysfunction, insider-outsider behavior, unintended consequences, and the self-fulfilling prophecy. These sociological principles provide the systems engineer with key approaches to manage the information flow through the organization as the disciplines are integrated and share their information. This also helps identify key sociological barriers to information flow through the organization. This paper will discuss this theoretical basis for the application of sociological principles to systems engineering.

Photoinduced toxicity of fluoranthene to northern leopard frogs (Rana pipiens)

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

Monson, P.D.; Call, D.J.; Cox, D.A.

1999-02-01

Rana pipiens larvae were exposed for 48 h in a flow-through system to clean water or five concentrations of the phototoxic polycyclic aromatic hydrocarbon (PAH) fluoranthene. Following this uptake period, the larvae were divided into four groups: one for immediate tissue residue analysis, a second for residue analysis following 48 h of depuration in clean water, and two for a 48-h exposure in clean water to ultraviolet (UV) light at two different levels. At the highest treatment, mean intensity was 8.12 {+-} 0.19 {times} 10{sup 2} {micro}W/cm{sup 2}, whereas at a lower treatment the UVA intensity was 4.45 {+-} 0.05more » {times} 10{sup 2} {micro}W/cm{sup 2}. Larval frogs bioaccumulated fluoranthene in direct proportion to the water exposure concentrations, with initial whole-body PAH concentrations of 1.48, 3.53, 4.85, 11.3, and 18.7 {micro}g/g at the five treatment levels. No mortality of the animals occurred during the 48-h uptake phase. When the frogs were placed in clean water, the fluoranthene was rapidly depurated, with up to 80% lost in 48 h. Exposure to UV light following fluoranthene exposure significantly enhanced toxicity of the PAH. Median time to death decreased as the product of UVA light intensity and fluoranthene body residue increased. For larval R. Pipiens, sufficient tissue residues of fluoranthene were bioaccumulated within 48 h, at water exposure concentrations in the range of 2 to 10 {micro}g/L, to be lethal when combined with a UVA exposure simulating a fraction of summertime, midday sunlight in northern latitudes.« less

Efficacy of Ultraviolet (UV-C) Light in a Thin-Film Turbulent Flow for the Reduction of Milkborne Pathogens.

PubMed

Crook, Jennifer A; Rossitto, Paul V; Parko, Jared; Koutchma, Tatiana; Cullor, James S

2015-06-01

Nonthermal technologies are being investigated as viable alternatives to, or supplemental utilization, with thermal pasteurization in the food-processing industry. In this study, the effect of ultraviolet (UV)-C light on the inactivation of seven milkborne pathogens (Listeria monocytogenes, Serratia marcescens, Salmonella Senftenberg, Yersinia enterocolitica, Aeromonas hydrophila, Escherichia coli, and Staphylococcus aureus) was evaluated. The pathogens were suspended in ultra-high-temperature whole milk and treated at UV doses between 0 and 5000 J/L at a flow rate of 4300 L/h in a thin-film turbulent flow-through pilot system. Of the seven milkborne pathogens tested, L. monocytogenes was the most UV resistant, requiring 2000 J/L of UV-C exposure to reach a 5-log reduction. The most sensitive bacterium was S. aureus, requiring only 1450 J/L to reach a 5-log reduction. This study demonstrated that the survival curves were nonlinear. Sigmoidal inactivation curves were observed for all tested bacterial strains. Nonlinear modeling of the inactivation data was a better fit than the traditional log-linear approach. Results obtained from this study indicate that UV illumination has the potential to be used as a nonthermal method to reduce microorganism populations in milk.

One step bioconversion of waste precious metals into Serratia biofilm-immobilized catalyst for Cr(VI) reduction.

PubMed

Yong, P; Liu, W; Zhang, Z; Beauregard, D; Johns, M L; Macaskie, L E

2015-11-01

For reduction of Cr(VI) the Pd-catalyst is excellent but costly. The objectives were to prove the robustness of a Serratia biofilm as a support for biogenic Pd-nanoparticles and to fabricate effective catalyst from precious metal waste. Nanoparticles (NPs) of palladium were immobilized on polyurethane reticulated foam and polypropylene supports via adhesive biofilm of a Serratia sp. The biofilm adhesion and cohesion strength were unaffected by palladization and catalytic biofilm integrity was also shown by magnetic resonance imaging. Biofilm-Pd and mixed precious metals on biofilm (biofilm-PM) reduced 5 mM Cr(VI) to Cr(III) when immobilized in a flow-through column reactor, at respective flow rates of 9 and 6 ml/h. The lower activity of the latter was attributed to fewer, larger, metal deposits on the bacteria. Activity was lost in each case at pH 7 but was restored by washing with 5 mM citrate solution or by exposure of columns to solution at pH 2, suggesting fouling by Cr(III) hydroxide product at neutral pH. A 'one pot' conversion of precious metal waste into new catalyst for waste decontamination was shown in a continuous flow system based on the use of Serratia biofilm to manufacture and support catalytic Pd-nanoparticles.

Effects of single low-temperature sauna bathing in patients with severe motor and intellectual disabilities

NASA Astrophysics Data System (ADS)

Iiyama, Junichi; Matsushita, Kensuke; Tanaka, Nobuyuki; Kawahira, Kazumi

2008-07-01

We have previously reported that thermal vasodilation following warm-water bathing and low-temperature sauna bathing (LTSB) at 60 °C for 15 min improves the cardiac function in patients with congestive heart failure. Through a comparative before-and-after study, we studied the hemodynamic and clinical effects of single exposure to LTSB in cerebral palsy (CP) patients who usually suffer from chilled extremities and low cardiac output. The study population comprised 16 patients ranging between 19 and 53 years with severe motor and intellectual disabilities. Noninvasive methods were used to estimate the systemic and peripheral circulatory changes before and after LTSB. Using blood flow velocity analysis, the pulsatile and resistive indexes of the peripheral arteries of the patients’ lower limbs were calculated. Following LTSB, the patients’ deep body temperature increased significantly by 1°C. Their heart rates increased and blood pressure decreased slightly. The total peripheral resistance decreased by 11%, and the cardiac output increased by 14%. There was significant improvement in the parameters that are indicative of the peripheral circulatory status, including the skin blood flow, blood flow velocity, pulsatile index, and resistive index. Numbness and chronic myalgia of the extremities decreased. There were no adverse side effects. Thus, it can be concluded that LTSB improves the peripheral circulation in CP patients.

Effects of single low-temperature sauna bathing in patients with severe motor and intellectual disabilities.

PubMed

Iiyama, Junichi; Matsushita, Kensuke; Tanaka, Nobuyuki; Kawahira, Kazumi

2008-07-01

We have previously reported that thermal vasodilation following warm-water bathing and low-temperature sauna bathing (LTSB) at 60 degrees C for 15 min improves the cardiac function in patients with congestive heart failure. Through a comparative before-and-after study, we studied the hemodynamic and clinical effects of single exposure to LTSB in cerebral palsy (CP) patients who usually suffer from chilled extremities and low cardiac output. The study population comprised 16 patients ranging between 19 and 53 years with severe motor and intellectual disabilities. Noninvasive methods were used to estimate the systemic and peripheral circulatory changes before and after LTSB. Using blood flow velocity analysis, the pulsatile and resistive indexes of the peripheral arteries of the patients' lower limbs were calculated. Following LTSB, the patients' deep body temperature increased significantly by 1 degrees C. Their heart rates increased and blood pressure decreased slightly. The total peripheral resistance decreased by 11%, and the cardiac output increased by 14%. There was significant improvement in the parameters that are indicative of the peripheral circulatory status, including the skin blood flow, blood flow velocity, pulsatile index, and resistive index. Numbness and chronic myalgia of the extremities decreased. There were no adverse side effects. Thus, it can be concluded that LTSB improves the peripheral circulation in CP patients.

Human respiration at rest in rapid compression and at high pressures and gas densities

NASA Technical Reports Server (NTRS)

Gelfand, R.; Lambertsen, C. J.; Strauss, R.; Clark, J. M.; Puglia, C. D.

1983-01-01

The ventilation (V), end-tidal PCO2 (PACO2), and CO2 elimination rate were determined in men at rest breathing CO2-free gas over the pressure range 1-50 ATA and the gas density range 0.4-25 g/l, during slow and rapid compressions, at stable elevated ambient pressures and during slow decompressions. Progressive increase in pulmonary gas flow resistance due to elevation of ambient pressure and inspired gas density to the He-O2 equivalent of 5000 feet of seawater was found to produce a complex pattern of change in PACO2. It was found that as both ambient pressure and pulmonary gas flow resistance were progressively raised, PACO2 at first increased, went through a maximum, and then declined towards values near the 1 ATA level. It is concluded that this pattern of PACO2 change results from the interaction on ventilation of the increase in pulmonary resistance due to the elevation of gas density with the increase in respiratory drive postulated as due to generalized central nervous system excitation associated with exposure to high hydrostatic pressure. It is suggested that a similar interaction exists between increased gas flow resistance and the increase in respiratory drive related to nitrogen partial pressure and the resulting narcosis.

Characterizing Microbe-Environment Interactions Through Experimental Evolution: The Autonomous Adaptive Directed Evolution Chamber

NASA Astrophysics Data System (ADS)

Ibanez, C. R.; Blaich, J.; Owyang, S.; Storrs, A.; Moffet, A.; Wong, N.; Zhou, J.; Gentry, D.

2015-12-01

We are developing a laboratory system for studying micro- to meso-scale interactions between microorganisms and their physicochemical environments. The Autonomous Adaptive Directed Evolution Chamber (AADEC) cultures microorganisms in controlled,small-scale geochemical environments. It observes corresponding microbial interactions to these environments and has the ability to adjust thermal, chemical, and other parameters in real time in response to these interactions. In addition to the sensed data, the system allows the generation of time-resolved ecological, genomic, etc. samples on the order of microbial generations. The AADEC currently houses cultures in liquid media and controls UVC radiation, heat exposure, and nutrient supply. In a proof-of-concept experimental evolution application, it can increase UVC radiation resistance of Escherichia coli cultures by iteratively exposing them to UVC and allowing the surviving cells to regrow. A baseline characterization generated a million fold resistance increase. This demonstration uses a single-well growth chamber prototype, but it was limited by scalability. We have expanded upon this system by implementing a microwell plate compatible fluidics system and sensor housing. This microwell plate system increases the diversity of microbial interactions seen in response to the geochemical environments generated by the system, allowing greater control over individual cultures' environments and detection of rarer events. The custom microfluidic card matches the footprint of a standard microwell plate. This card enables controllable fluid flow between wells and introduces multiple separate exposure and sensor chambers, increasing the variety of sensors compatible with the system. This gives the device control over scale and the interconnectedness of environments within the system. The increased controllability of the multiwell system provides a platform for implementing machine learning algorithms that will autonomously adjust geochemical environmental parameters.

Derivative financial instruments and nonprofit health care providers.

PubMed

Stewart, Louis J; Owhoso, Vincent

2004-01-01

This article examines the extent of derivative financial instrument use among US nonprofit health systems and the impact of these financial instruments on their cash flows, reported operating results, and financial risks. Our examination is conducted through a case study of New Jersey hospitals and health systems. We review the existing literature on interest rate derivative instruments and US hospitals and health systems. This literature describes the design of these derivative financial instruments and the theoretical benefits of their use by large health care provider organizations. Our contribution to the literature is to provide an empirical evaluation of derivative financial instruments usage among a geographically limited sample of US nonprofit health systems. We reviewed the audited financial statements of the 49 community hospitals and multi-hospital health systems operating in the state of New Jersey. We found that 8 percent of New Jersey's nonprofit health providers utilized interest rate derivatives with an aggregate principle value of $229 million. These derivative users combine interest rate swaps and caps to lower the effective interest costs of their long-term debt while limiting their exposure to future interest rate increases. In addition, while derivative assets and liabilities have an immaterial balance sheet impact, derivative related gains and losses are a material component of their reported operating results. We also found that derivative usage among these four health systems was responsible for generating positive cash flows in the range of 1 percent to 2 percent of their total 2001 cash flows from operations. As a result of our admittedly limited samples we conclude that interest rate swaps and caps are effective risk management tools. However, we also found that while these derivative financial instruments are useful hedges against the risks of issuing long-term financing instruments, they also expose derivative users to credit, contract termination and interest rate volatility risks. In conclusion, we find that these financial instruments can also generate negative as well as positive cash flows and have both a positive and negative impact on reported operating results.

Microfluidic control of droplet formation from stable emulsions formed by aqueous two-phase systems

NASA Astrophysics Data System (ADS)

Teixeira, Alyne G.; Tsai, Meng-Chiao; Frampton, John P.

2018-02-01

Aqueous two-phase systems (ATPSs) form from the thermodynamic separation of two dissolved incompatible solutes, such as two polymers, a polymer and a salt, and a polymer and a surfactant. At most supercritical concentrations, ATPS emulsions can be formed by vigorous mixing. These emulsions typically settle into distinct layers in minutes to hours. However, it is also possible to choose ATPS compositions with extremely long settling times that resemble stable emulsions. Here, we generated stable emulsions from a polyethylene glycol (PEG)-dextran ATPS by selecting ATPS compositions at the extreme ends of the tie lines connecting the binodal curve delineating phase-separating compositions. Droplets of PEG in a continuous dextran phase did not coalesce appreciably over the course of several days when stored in a conical tube or syringe. However, upon exposure to laminar flow conditions in a microfluidic channel, droplets were observed to coalesce. Through microscopic characterization of droplet volume, an increase in droplet size and decrease in overall droplet number was observed as a function of channel distance, suggesting a progressive droplet merging phenomenon. This novel approach to control droplet size by encouraging coalescence of stable emulsions under laminar flow in a microfluidic channel enables the production of droplets ranging from fL to several pL, which may enable various future biotechnology applications.

Measurement of the initial phase of ozone decomposition in water and wastewater by means of a continuous quench-flow system: application to disinfection and pharmaceutical oxidation.

PubMed

Buffle, Marc-Olivier; Schumacher, Jochen; Salhi, Elisabeth; Jekel, Martin; von Gunten, Urs

2006-05-01

Due to a lack of adequate experimental techniques, the kinetics of the first 20s of ozone decomposition in natural water and wastewater is still poorly understood. Introducing a continuous quench-flow system (CQFS), measurements starting 350 ms after ozone addition are presented for the first time. Very high HO. to O3 exposures ratios (Rct=integralHO.dt/integralO3dt) reveal that the first 20s of ozonation present oxidation conditions that are similar to ozone-based advanced oxidation processes (AOP). The oxidation of carbamazepine could be accurately modeled using O3 and HO. exposures measured with CQFS during wastewater ozonation. These results demonstrate the applicability of bench scale determined second-order rate constants for wastewater ozonation. Important degrees of pharmaceutical oxidation and microbial inactivation are predicted, indicating that a significant oxidation potential is available during wastewater ozonation, even when ozone is entirely decomposed in the first 20s.

The preservation of ancient solar wind particles buried beneath lunar basalt flows as determined through heat transfer modeling

NASA Astrophysics Data System (ADS)

Rumpf, M. E.; Fagents, S. A.; Crawford, I. A.; Joy, K. H.

2009-12-01

The ever-changing environment on the Earth’s surface has erased any record of the early solar system. However, the antiquity of lunar surface combined with its negligible atmosphere and magnetosphere would have created conditions favorable for the preservation of ancient solar wind particles, galactic cosmic ray particles, and material that originated on other bodies in the inner solar system. Ancient particles emplaced in the regolith and subsequently buried beneath mare lava flows may have been preserved from subsequent bombardment provided the volatiles survived heat introduced by the lava flow. Discovery and extraction of such particles will aid in the advancement of several current solar system exploration goals, including studying the record of solar wind gases and investigating ancient atmospheric compositions on Earth and other inner planets. It has been shown that different volatile species will be released from the regolith when heated to specific temperature ranges between 573 and 973 K. We have developed a finite-volume numerical model that simulates heat transfer between a mare lava flow and the underlying regolith, to predict the preservation potential of ancient particles within layered deposits in the lunar maria. Results show that a 1 m thick basalt flow initially at 1500 K will heat an underlying regolith deposit to release implanted volatile species buried to a depth of 3.7 to 28 cm beneath the regolith surface; pristine samples would be preserved beneath these depths. At the estimated regolith formation rate of ~5 mm/Ma during the peak of mare volcanism (~3.6-3.8 Ga), an exposure time exceeding 7.4 to 56 Ma would be required prior to burial by the ensuing lava flow. Heating depths and required regolith formation times scale in direct proportion to the thickness of the overlying flow. Emplacement of multiple flow units over several hundred Ma would create intercalated stacks of lavas and regolith units, which could be radiometrically dated to provide a time series of the variability in intensity and composition of the solar wind. Suitable locations include Oceanus Procellarum, which contains numerous lava units ranging in age from 3.5-1.2 Ga. Extraction of implanted volatiles of a range of ages would require drilling through perhaps tens of meters of flow units and intervening paleoregoliths, which in turn indicates the need for tens to hundreds of km surface mobility and the provision for adequate sample collection and return. Detection of suitable paleoregolith deposits would be aided by tools such as ground penetrating radar. Although it may be argued that long-range robotic rover and sample return missions could tackle this objective, we propose that the complexity of the task is most readily addressed by a sortie-class human expedition to key sites in the lunar maria.

Does Waterborne Exposure Explain Effects Caused by Neonicotinoid-Contaminated Plant Material in Aquatic Systems?

PubMed

Englert, Dominic; Zubrod, Jochen P; Link, Moritz; Mertins, Saskia; Schulz, Ralf; Bundschuh, Mirco

2017-05-16

Neonicotinoids are increasingly applied on trees as protection measure against insect pests. Consequently, neonicotinoids are inevitably transferred into aquatic environments either via spray drift or surface runoff or (due to neonicotinoids' systemic nature) via senescent leaves. There particularly leaf-shredding invertebrates may be exposed to neonicotinoids through both the water phase and the consumption of contaminated leaves. In 7 day bioassays (n = 30), we examined ecotoxicological differences between these two exposure scenarios for an amphipod and an insect nymph with their feeding rate as the response variable. Organisms either experienced waterborne neonicotinoid (i.e., imidacloprid, thiacloprid, and acetamiprid) exposure only or a combined exposure (waterborne and dietary) through both the consumption of contaminated leaves and neonicotinoids leaching from leaves into water. The amphipod (7 day EC 50 s from 0.3 to 8.4 μg/L) was more sensitive than the insect nymph (7 day EC 50 s from 7.0 to 19.4 μg/L). Moreover, for both species, concentration-response models derived from water concentrations indicated higher effects under the combined exposure. Together with the observed inability of shredders to avoid neonicotinoid-contaminated leaves, our results emphasize the relevance of dietary exposure (e.g., via leaves) for systemic insecticides. Thus, it would be prudent to consider dietary exposure during the registration of systemic insecticides to safeguard ecosystem integrity.

Vaporizing particle velocimeter

NASA Technical Reports Server (NTRS)

Weinstein, Leonard M. (Inventor)

1992-01-01

A velocimeter measures flow characteristics of a flow traveling through a chamber in a given direction. Tracer particles are entrained in the flow and a source of radiant energy produces an output stream directed transversely to the chamber, having a sufficient intensity to vaporize the particles as they pass through the output stream. Each of the vaporized particles explodes to produce a shock wave and a hot core, and a flow visualization system tracks the motion of the hot cores and shock waves to measure the velocity of each tracer particle and the temperature of the flow around the tracer.

Evaluation of an ARPS-based canopy flow modeling system for use in future operational smoke prediction efforts

Treesearch

M. T. Kiefer; S. Zhong; W. E. Heilman; J. J. Charney; X. Bian

2013-01-01

Efforts to develop a canopy flow modeling system based on the Advanced Regional Prediction System (ARPS) model are discussed. The standard version of ARPS is modified to account for the effect of drag forces on mean and turbulent flow through a vegetation canopy, via production and sink terms in the momentum and subgrid-scale turbulent kinetic energy (TKE) equations....

Patent ductus arteriosus: patho-physiology, hemodynamic effects and clinical complications.

PubMed

Capozzi, Giovanbattista; Santoro, Giuseppe

2011-10-01

During fetal life, patent arterial duct diverts placental oxygenated blood from the pulmonary artery into the aorta by-passing lungs. After birth, decrease of prostacyclins and prostaglandins concentration usually causes arterial duct closure. This process may be delayed, or may even completely fail in preterm infants with arterial duct still remaining patent. If that happens, blood flow by-pass of the systemic circulation through the arterial duct results in pulmonary overflow and systemic hypoperfusion. When pulmonary flow is 50% higher than systemic flow, a hemodynamic "paradox" results, with an increase of left ventricular output without a subsequent increase of systemic output. Cardiac overload support neuro-humoral effects (activation of sympathetic nervous system and renin-angiotensin system) that finally promote heart failure. Moreover, increased pulmonary blood flow can cause vascular congestion and pulmonary edema. However, the most dangerous effect is cerebral under-perfusion due to diastolic reverse-flow and resulting in cerebral hypoxia. At last, blood flow decreases through the abdominal aorta, reducing perfusion of liver, gut and kidneys and may cause hepatic failure, renal insufficiency and necrotizing enterocolitis. Conclusions Large patent arterial duct may cause life-threatening multi-organ effects. In pre-term infant early diagnosis and timely effective treatment are cornerstones in the prevention of cerebral damage and long-term multi-organ failure.

Fiber-optic system for checking the acoustical parameters of gas-turbine engine flow-through passages

NASA Astrophysics Data System (ADS)

Vinogradov, Vasiliy Y.; Morozov, Oleg G.; Nureev, Ilnur I.; Kuznetzov, Artem A.

2015-03-01

In this paper we consider the integrated approach to development of the aero-acoustical methods for diagnostics of aircraft gas-turbine engine flow-through passages by using as the base the passive fiber-optic and location technologies.

DynaMiTES - A dynamic cell culture platform for in vitro drug testing PART 1 - Engineering of microfluidic system and technical simulations.

PubMed

Mattern, Kai; Beißner, Nicole; Reichl, Stephan; Dietzel, Andreas

2018-05-01

Conventional safety and efficacy test models, such as animal experiments or static in vitro cell culture models, can often not reliably predict the most promising drug candidates. Therefore, a novel microfluidic cell culture platform, called Dynamic Micro Tissue Engineering System (DynaMiTES), was designed to allow online analysis of drugs permeating through barrier forming tissues under dynamic conditions combined with monitoring of the transepithelial electrical resistance (TEER) by electrodes optimized for homogeneous current distribution. A variety of pre-cultivated cell culture inserts can be integrated and exposed to well controlled dynamic micro flow conditions, resulting in a tightly regulated exposure of the cells to tested drugs, drug formulations and shear forces. With these qualities, the new system can provide more relevant information compared to static measurements. As a first in vitro model, a three-dimensional hemicornea construct consisting of human keratocytes (HCK-Ca) and epithelial cells (HCE-T) was successfully tested in the DynaMiTES. Thereby, we were able to demonstrate the functionality and cell compatibility of this new organ on chip test platform. The modular design of the DynaMiTES allows fast adaptation suitable for the investigation of drug permeation through other important cellular barriers. Copyright © 2017. Published by Elsevier B.V.

Reprint of "Potential seminal transport of pharmaceuticals to the conceptus".

PubMed

Scialli, Anthony R; Bailey, Graham; Beyer, Bruce K; Bøgh, Ingrid Brück; Breslin, William J; Chen, Connie L; DeLise, Anthony M; Hui, Julia Y; Moffat, Graeme J; Stewart, Jane; Thompson, Kary E

2016-01-01

Small molecule pharmaceutical products are assumed to reach concentrations in semen similar to those in blood plasma. Exposure modeling for these small-molecule products in humans assumes a daily dose of 5mL of semen and 100% absorption from the vagina with distribution to the conceptus through the maternal systemic circulation. Monoclonal antibody drugs are present in semen at concentrations about 2% or less of those in blood, and the modeling used for small molecules will over-estimate the possibility of conceptus exposure to immunoglobulins. It is not known whether peptide products reach semen, but in general peptide medications are destroyed by vaginal peptidases, and conceptus exposure is predicted to be minimal. Theoretical exposure routes to pharmaceuticals that might result in exposure of the conceptus greater than that of maternal systemic exposures include direct access through the cervical canal, adsorption to sperm for carriage into the oocyte, and direct delivery from the vaginal veins or lymphatics to the uterine artery. There is some evidence for direct access to the uterus for progesterone, terbutaline, and danazol, but the evidence does not involve exposures during pregnancy in most instances. Studies in mice, rats, rabbits, and monkeys do not suggest that exposure to small molecule pharmaceuticals in semen imposes risks to the conceptus beyond those that can be predicted using modeling of systemic maternal exposure. Monoclonal antibody and peptide exposure in semen does not pose a significant risk to the conceptus. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Potential seminal transport of pharmaceuticals to the conceptus.

PubMed

Scialli, Anthony R; Bailey, Graham; Beyer, Bruce K; Bøgh, Ingrid Brück; Breslin, William J; Chen, Connie L; DeLise, Anthony M; Hui, Julia Y; Moffat, Graeme J; Stewart, Jane; Thompson, Kary E

2015-12-01

Small molecule pharmaceutical products are assumed to reach concentrations in semen similar to those in blood plasma. Exposure modeling for these small-molecule products in humans assumes a daily dose of 5mL of semen and 100% absorption from the vagina with distribution to the conceptus through the maternal systemic circulation. Monoclonal antibody drugs are present in semen at concentrations about 2% or less of those in blood, and the modeling used for small molecules will over-estimate the possibility of conceptus exposure to immunoglobulins. It is not known whether peptide products reach semen, but in general peptide medications are destroyed by vaginal peptidases, and conceptus exposure is predicted to be minimal. Theoretical exposure routes to pharmaceuticals that might result in exposure of the conceptus greater than that of maternal systemic exposures include direct access through the cervical canal, adsorption to sperm for carriage into the oocyte, and direct delivery from the vaginal veins or lymphatics to the uterine artery. There is some evidence for direct access to the uterus for progesterone, terbutaline, and danazol, but the evidence does not involve exposures during pregnancy in most instances. Studies in mice, rats, rabbits, and monkeys do not suggest that exposure to small molecule pharmaceuticals in semen imposes risks to the conceptus beyond those that can be predicted using modeling of systemic maternal exposure. Monoclonal antibody and peptide exposure in semen does not pose a significant risk to the conceptus. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

A model for closing the inviscid form of the average-passage equation system

NASA Technical Reports Server (NTRS)

Adamczyk, J. J.; Mulac, R. A.; Celestina, M. L.

1985-01-01

A mathematical model is proposed for closing or mathematically completing the system of equations which describes the time average flow field through the blade passages of multistage turbomachinery. These equations referred to as the average passage equation system govern a conceptual model which has proven useful in turbomachinery aerodynamic design and analysis. The closure model is developed so as to insure a consistency between these equations and the axisymmetric through flow equations. The closure model was incorporated into a computer code for use in simulating the flow field about a high speed counter rotating propeller and a high speed fan stage. Results from these simulations are presented.

Quasi-one-dimensional compressible flow across face seals and narrow slots. 2: Computer program

NASA Technical Reports Server (NTRS)

Zuk, J.; Smith, P. J.

1972-01-01

A computer program is presented for compressible fluid flow with friction across face seals and through narrow slots. The computer program carries out a quasi-one-dimensional flow analysis which is valid for laminar and turbulent flows under both subsonic and choked flow conditions for parallel surfaces. The program is written in FORTRAN IV. The input and output variables are in either the International System of Units (SI) or the U.S. customary system.

Buildings operations and ETS exposure.

PubMed Central

Spengler, J D

1999-01-01

Mechanical systems are used in buildings to provide conditioned air, dissipate thermal loads, dilute contaminants, and maintain pressure differences. The characteristics of these systems and their operations h implications for the exposures of workers to environmental tobacco smoke (ETS) and for the control of these exposures. This review describes the general features of building ventilation systems and the efficacy of ventilation for controlling contaminant concentrations. Ventilation can reduce the concentration of ETS through dilution, but central heating, ventilating, and air conditioning (HVAC) can also move air throughout a building that has been contaminated by ETS. An understanding of HVAC systems is needed to develop models for exposures of workers to ETS. Images Figure 1 Figure 2 Figure 3 PMID:10375293

Groundwater Flow Systems at the Nevada Test Site, Nevada: A Synthesis of Potentiometric Contours, Hydrostratigraphy, and Geologic Structures

USGS Publications Warehouse

Fenelon, Joseph M.; Sweetkind, Donald S.; Laczniak, Randell J.

2010-01-01

Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulic-head distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial-volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial-volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial-volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions throughout the study area are dominantly south-southwest with some local deviations. Vertical hydraulic gradients between aquifer types are downward throughout most of the study area; however, flow from the alluvial-volcanic aquifer into the underlying carbonate aquifer, where both aquifers are present, is believed to be minor because of an intervening confining unit. Limited exchange of water between aquifer types occurs by diffuse flow through the confining unit, by focused flow along fault planes, or by direct flow where the confining unit is locally absent. Interflow between regional aquifers is evaluated and mapped to define major flow paths. These flow paths delineate tributary flow systems, which converge to form intermediate and regional flow systems. The implications of these flow systems in controlling transport of radionuclides away from the underground test areas at the Nevada Test Site are briefly discussed. Additionally, uncertainties in the delineation of aquifers, the development of potentiometric contours, and the identification of flow systems are identified and evaluated. Eleven tributary flow systems and three larger flow systems are mapped in the Nevada Test Site area. Flow systems within the alluvial-volcanic aquifer dominate the western half of the study area, whereas flow systems within the carbonate aquifer are most prevalent in the southeastern half of the study area. Most of the flow in the regional alluvial-volcanic aquifer that moves through the underground testing area on Pahute Mesa is discharged to the land surface at springs and seeps in Oasis Valley. Flow in the regional carbonate aquifer is internally compartmentalized by major geologic structures, primarily thrust faults, which constrain flow into separate corridors. Contaminants that reach the regional carbonate aquifer from testing areas in Yucca and Frenchman Flats flow toward downgradient discharge areas through the Alkali Flat-Furnace Creek Ranch or Ash Meadows flow systems and their tributaries.

μ-PIV measurements of the ensemble flow fields surrounding a migrating semi-infinite bubble.

PubMed

Yamaguchi, Eiichiro; Smith, Bradford J; Gaver, Donald P

2009-08-01

Microscale particle image velocimetry (μ-PIV) measurements of ensemble flow fields surrounding a steadily-migrating semi-infinite bubble through the novel adaptation of a computer controlled linear motor flow control system. The system was programmed to generate a square wave velocity input in order to produce accurate constant bubble propagation repeatedly and effectively through a fused glass capillary tube. We present a novel technique for re-positioning of the coordinate axis to the bubble tip frame of reference in each instantaneous field through the analysis of the sudden change of standard deviation of centerline velocity profiles across the bubble interface. Ensemble averages were then computed in this bubble tip frame of reference. Combined fluid systems of water/air, glycerol/air, and glycerol/Si-oil were used to investigate flows comparable to computational simulations described in Smith and Gaver (2008) and to past experimental observations of interfacial shape. Fluorescent particle images were also analyzed to measure the residual film thickness trailing behind the bubble. The flow fields and film thickness agree very well with the computational simulations as well as existing experimental and analytical results. Particle accumulation and migration associated with the flow patterns near the bubble tip after long experimental durations are discussed as potential sources of error in the experimental method.

CONCENTRATION-RESPONSE ASSESSMENT OF CHEMICAL EFFECTS ON SYNAPTOGENESIS USING A HIGH CONTENT IMAGE ANALYSIS-BASED SCREENING ASSAY

EPA Science Inventory

Functional connectivity of the nervous system is dependent upon the development of synapses: i.e. specialized cell-cell contacts which facilitate the unidirectional flow of fast neurotransmission. Prenatal and/or early postnatal exposure to chemicals which disrupt synaptogenesis ...

Large volume flow-through scintillating detector

DOEpatents

Gritzo, Russ E.; Fowler, Malcolm M.

1995-01-01

A large volume flow through radiation detector for use in large air flow situations such as incinerator stacks or building air systems comprises a plurality of flat plates made of a scintillating material arranged parallel to the air flow. Each scintillating plate has a light guide attached which transfers light generated inside the scintillating plate to an associated photomultiplier tube. The output of the photomultiplier tubes are connected to electronics which can record any radiation and provide an alarm if appropriate for the application.

Marine floc strength and breakup response in turbulent flow

NASA Astrophysics Data System (ADS)

Rau, Matthew; Ackleson, Steven; Smith, Geoffrey

2017-11-01

The effect of turbulence on marine floc formation and breakup is studied experimentally using a recirculating breakup facility. Flocs of bentonite clay particles are grown in a large, stirred aggregation tank of salt water (salinity of 10 ppt) before being subjected to fully-developed pipe flow. Pipe flow conditions range from laminar to turbulent with dissipation rates up to 2.1 m2/s3. Particle size distributions are measured through in-situ sampling of the small-angle forward volume scattering function and through microscopic imaging. Floc size is compared before and after exposure to turbulence and found to be a strong function of the dissipation rate of turbulent kinetic energy. Hydrodynamic conditions within the aggregation tank have a large influence on overall floc strength; flocs formed with stirred aggregation resist breakup compared to flocs formed without stirring. Floc shape and structure statistics are quantified through image analysis and the results are discussed in relation to the measured floc breakup response. Finally, the relevance of these findings to quantifying and predicting marine floc dynamics and the eventual fate of particles in the ocean is presented. The authors thank the National Research Council Postdoctoral Program for their support of this work.

Heating and cooling system for an on-board gas adsorbent storage vessel

DOEpatents

Tamburello, David A.; Anton, Donald L.; Hardy, Bruce J.; Corgnale, Claudio

2017-06-20

In one aspect, a system for controlling the temperature within a gas adsorbent storage vessel of a vehicle may include an air conditioning system forming a continuous flow loop of heat exchange fluid that is cycled between a heated flow and a cooled flow. The system may also include at least one fluid by-pass line extending at least partially within the gas adsorbent storage vessel. The fluid by-pass line(s) may be configured to receive a by-pass flow including at least a portion of the heated flow or the cooled flow of the heat exchange fluid at one or more input locations and expel the by-pass flow back into the continuous flow loop at one or more output locations, wherein the by-pass flow is directed through the gas adsorbent storage vessel via the by-pass line(s) so as to adjust an internal temperature within the gas adsorbent storage vessel.

Sequential geophysical and flow inversion to characterize fracture networks in subsurface systems

DOE PAGES

Mudunuru, Maruti Kumar; Karra, Satish; Makedonska, Nataliia; ...

2017-09-05

Subsurface applications, including geothermal, geological carbon sequestration, and oil and gas, typically involve maximizing either the extraction of energy or the storage of fluids. Fractures form the main pathways for flow in these systems, and locating these fractures is critical for predicting flow. However, fracture characterization is a highly uncertain process, and data from multiple sources, such as flow and geophysical are needed to reduce this uncertainty. We present a nonintrusive, sequential inversion framework for integrating data from geophysical and flow sources to constrain fracture networks in the subsurface. In this framework, we first estimate bounds on the statistics formore » the fracture orientations using microseismic data. These bounds are estimated through a combination of a focal mechanism (physics-based approach) and clustering analysis (statistical approach) of seismic data. Then, the fracture lengths are constrained using flow data. In conclusion, the efficacy of this inversion is demonstrated through a representative example.« less

Sequential geophysical and flow inversion to characterize fracture networks in subsurface systems

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

Mudunuru, Maruti Kumar; Karra, Satish; Makedonska, Nataliia

Subsurface applications, including geothermal, geological carbon sequestration, and oil and gas, typically involve maximizing either the extraction of energy or the storage of fluids. Fractures form the main pathways for flow in these systems, and locating these fractures is critical for predicting flow. However, fracture characterization is a highly uncertain process, and data from multiple sources, such as flow and geophysical are needed to reduce this uncertainty. We present a nonintrusive, sequential inversion framework for integrating data from geophysical and flow sources to constrain fracture networks in the subsurface. In this framework, we first estimate bounds on the statistics formore » the fracture orientations using microseismic data. These bounds are estimated through a combination of a focal mechanism (physics-based approach) and clustering analysis (statistical approach) of seismic data. Then, the fracture lengths are constrained using flow data. In conclusion, the efficacy of this inversion is demonstrated through a representative example.« less

Scattering matrix elements of biological particles measured in a flow through system: theory and practice.

PubMed

Sloot, P M; Hoekstra, A G; van der Liet, H; Figdor, C G

1989-05-15

Light scattering techniques (including depolarization experiments) applied to biological cells provide a fast nondestructive probe that is very sensitive to small morphological differences. Until now quantitative measurement of these scatter phenomena were only described for particles in suspension. In this paper we discuss the symmetry conditions applicable to the scattering matrices of monodisperse biological cells in a flow cytometer and provide evidence that quantitative measurement of the elements of these scattering matrices is possible in flow through systems. Two fundamental extensions to the theoretical description of conventional scattering experiments are introduced: large cone integration of scattering signals and simultaneous implementation of the localization principle to account for scattering by a sharply focused laser beam. In addition, a specific calibration technique is proposed to account for depolarization effects of the highly specialized optics applied in flow through equipment.

A locally conservative stabilized continuous Galerkin finite element method for two-phase flow in poroelastic subsurfaces

NASA Astrophysics Data System (ADS)

Deng, Q.; Ginting, V.; McCaskill, B.; Torsu, P.

2017-10-01

We study the application of a stabilized continuous Galerkin finite element method (CGFEM) in the simulation of multiphase flow in poroelastic subsurfaces. The system involves a nonlinear coupling between the fluid pressure, subsurface's deformation, and the fluid phase saturation, and as such, we represent this coupling through an iterative procedure. Spatial discretization of the poroelastic system employs the standard linear finite element in combination with a numerical diffusion term to maintain stability of the algebraic system. Furthermore, direct calculation of the normal velocities from pressure and deformation does not entail a locally conservative field. To alleviate this drawback, we propose an element based post-processing technique through which local conservation can be established. The performance of the method is validated through several examples illustrating the convergence of the method, the effectivity of the stabilization term, and the ability to achieve locally conservative normal velocities. Finally, the efficacy of the method is demonstrated through simulations of realistic multiphase flow in poroelastic subsurfaces.

Investigation of Coronal Leakage of Root Fillings after Smear Layer Removal with EDTA or Er,Cr:YSGG Laser through Capillary Flow Porometry

PubMed Central

Vergauwen, Tom Edgard Maria; Michiels, Rafaël; Torbeyns, Dries; Meire, Maarten; De Moor, Roeland Jozef Gentil

2014-01-01

No studies have been performed evaluating the marginal seal of root fillings after direct exposure of root canal (RC) walls to Er,Cr:YSGG laser irradiation. Therefore, 75 root filled teeth (5 × 15–cold lateral condensation) were analyzed for through-and-through leakage (TTL) using capillary flow porometry (CFP). The cleaning protocol determined the experimental groups: (1) irrigation with NaOCl 2.5% and EDTA 17% or standard protocol (SP), (2) SP + Er,Cr:YSGG lasing (dried RC), (3) NaOCl 2.5% + Er,Cr:YSGG lasing (dried RC), (4) SP + Er,Cr:YSGG lasing (wet RC), and (5) NaOCl 2.5% + Er,Cr:YSGG lasing (wet RC). Groups 6 to 10 consisted of the same filled teeth with resected apices. Resection was performed after the first CFP measurement. CFP was used to assess minimum, mean flow, and maximum pore diameters after 48 h. Statistics were performed using nonparametric tests (P > 0.05). Additional three roots per group were submitted to SEM of the RC walls. TTL was observed in all groups without statistically significant differences between the different groups for minimum, mean, and maximum pore diameter (P > 0.05). In this study, the use of EDTA and/or Er,Cr:YSGG laser did not reduce through-and-through leakage in nonresected and resected roots. PMID:24696685

Contaminant concentration versus flow velocity: drivers of biodegradation and microbial growth in groundwater model systems.

PubMed

Grösbacher, Michael; Eckert, Dominik; Cirpka, Olaf A; Griebler, Christian

2018-06-01

Aromatic hydrocarbons belong to the most abundant contaminants in groundwater systems. They can serve as carbon and energy source for a multitude of indigenous microorganisms. Predictions of contaminant biodegradation and microbial growth in contaminated aquifers are often vague because the parameters of microbial activity in the mathematical models used for predictions are typically derived from batch experiments, which don't represent conditions in the field. In order to improve our understanding of key drivers of natural attenuation and the accuracy of predictive models, we conducted comparative experiments in batch and sediment flow-through systems with varying concentrations of contaminant in the inflow and flow velocities applying the aerobic Pseudomonas putida strain F1 and the denitrifying Aromatoleum aromaticum strain EbN1. We followed toluene degradation and bacterial growth by measuring toluene and oxygen concentrations and by direct cell counts. In the sediment columns, the total amount of toluene degraded by P. putida F1 increased with increasing source concentration and flow velocity, while toluene removal efficiency gradually decreased. Results point at mass transfer limitation being an important process controlling toluene biodegradation that cannot be assessed with batch experiments. We also observed a decrease in the maximum specific growth rate with increasing source concentration and flow velocity. At low toluene concentrations, the efficiencies in carbon assimilation within the flow-through systems exceeded those in the batch systems. In all column experiments the number of attached cells plateaued after an initial growth phase indicating a specific "carrying capacity" depending on contaminant concentration and flow velocity. Moreover, in all cases, cells attached to the sediment dominated over those in suspension, and toluene degradation was performed practically by attached cells only. The observed effects of varying contaminant inflow concentration and flow velocity on biodegradation could be captured by a reactive-transport model. By monitoring both attached and suspended cells we could quantify the release of new-grown cells from the sediments to the mobile aqueous phase. Studying flow velocity and contaminant concentrations as key drivers of contaminant transformation in sediment flow-through microcosms improves our system understanding and eventually the prediction of microbial biodegradation at contaminated sites.

Development of an on-line exposure system to determine freshly produced diesel engine emission-induced cellular effects.

PubMed

Oostingh, Gertie J; Papaioannou, Eleni; Chasapidis, Leonidas; Akritidis, Theofylaktos; Konstandopoulos, Athanasios G; Duschl, Albert

2013-09-01

Diesel engine emission particle filters are often placed at exhaust outlets to remove particles from the exhaust. The use of filters results in the exposure to a reduced number of nanometer-sized particles, which might be more harmful than the exposure to a larger number of micrometer-sized particles. An in vitro exposure system was established to expose human alveolar epithelial cells to freshly generated exhaust. Computer simulations were used to determine the optimal flow characteristics and ensure equal exposure conditions for each well of a 6-well plate. A selective particle size sampler was used to continuously deliver diesel soot particles with different particle size distributions to cells in culture. To determine, whether the system could be used for cellular assays, alterations in cytokine production and cell viability of human alveolar A549 cells were determined after 3h on-line exposure followed by a 21-h conventional incubation period. Data indicated that complete diesel engine emission slightly affected pre-stimulated cells, but naive cells were not affected. The fractions containing large or small particles never affected the cells. The experimental set-up allowed a reliable exposure of the cells to the complete exhaust fraction or to the fractions containing either large or small diesel engine emission particles. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pilot Study for UVA-LED Disinfection of Escherichia coli in Water for Space and Earth Applications

NASA Technical Reports Server (NTRS)

Ragolta, Carolina

2010-01-01

To test the efficacy of UVA-LED disinfection, a solution of Escherichia coli was pumped through a modified drip flow reactor at a flow rate of 1 ml/min. The experiment was conducted in a controlled environment chamber to ensure that temperature did not cause disinfection. The reactor featured three wells with different treatments: UVA-LED irradiation, UVA-LEDs with Ti02, and UVA-LEDs with nanosilver. Samples from each well were taken throughout a 340 hour period, inactivated, assayed, and analyzed for E. coli disinfection. Results of the duplicate experiments indicated longer exposure times are needed for UVA-LED disinfection of E. coli in water. Further research would consider a longer sampling period and different test conditions, such as increased contact area and various flow rates.

System for ranking relative threats of U.S. volcanoes

USGS Publications Warehouse

Ewert, J.W.

2007-01-01

A methodology to systematically rank volcanic threat was developed as the basis for prioritizing volcanoes for long-term hazards evaluations, monitoring, and mitigation activities. A ranking of 169 volcanoes in the United States and the Commonwealth of the Northern Mariana Islands (U.S. volcanoes) is presented based on scores assigned for various hazard and exposure factors. Fifteen factors define the hazard: Volcano type, maximum known eruptive explosivity, magnitude of recent explosivity within the past 500 and 5,000 years, average eruption-recurrence interval, presence or potential for a suite of hazardous phenomena (pyroclastic flows, lahars, lava flows, tsunami, flank collapse, hydrothermal explosion, primary lahar), and deformation, seismic, or degassing unrest. Nine factors define exposure: a measure of ground-based human population in hazard zones, past fatalities and evacuations, a measure of airport exposure, a measure of human population on aircraft, the presence of power, transportation, and developed infrastructure, and whether or not the volcano forms a significant part of a populated island. The hazard score and exposure score for each volcano are multiplied to give its overall threat score. Once scored, the ordered list of volcanoes is divided into five overall threat categories from very high to very low. ?? 2007 ASCE.

Hydrogeologic Framework and Ground Water in Basin-Fill Deposits of the Diamond Valley Flow System, Central Nevada

USGS Publications Warehouse

Tumbusch, Mary L.; Plume, Russell W.

2006-01-01

The Diamond Valley flow system, an area of about 3,120 square miles in central Nevada, consists of five hydrographic areas: Monitor, Antelope, Kobeh, and Diamond Valleys and Stevens Basin. Although these five areas are in a remote part of Nevada, local government officials and citizens are concerned that the water resources of the flow system eventually could be further developed for irrigation or mining purposes or potentially for municipal use outside the study area. In order to better understand the flow system, the U.S. Geological Survey in cooperation with Eureka, Lander, and Nye Counties and the Nevada Division of Water Resources, is conducting a multi-phase study of the flow system. The principal aquifers of the Diamond Valley flow system are in basin-fill deposits that occupy structural basins comprised of carbonate rocks, siliciclastic sedimentary rocks, igneous intrusive rocks, and volcanic rocks. Carbonate rocks also function as aquifers, but their extent and interconnections with basin-fill aquifers are poorly understood. Ground-water flow in southern Monitor Valley is from the valley margins toward the valley axis and then northward to a large area of discharge by evapotranspiration (ET) that is formed south of a group of unnamed hills near the center of the valley. Ground-water flow from northern Monitor Valley, Antelope Valley, and northern and western parts of Kobeh Valley converges to an area of ground-water discharge by ET in central and eastern Kobeh Valley. Prior to irrigation development in the 1960s, ground-water flow in Diamond Valley was from valley margins toward the valley axis and then northward to a large discharge area at the north end of the valley. Stevens Basin is a small upland basin with internal drainage and is not connected with other parts of the flow system. After 40 years of irrigation pumping, a large area of ground-water decline has developed in southern Diamond Valley around the irrigated area. In this part of Diamond Valley, flow is from valley margins toward the irrigated area. In northern Diamond Valley, flow appears to remain generally northward to the large discharge area. Subsurface flow through mountain ranges has been identified from Garden Valley (outside the study area) through the Sulphur Springs Range to Diamond Valley and from southeastern Antelope Valley through the Fish Creek Range to Little Smoky Valley (outside the study area). In both cases, the flow is probably through carbonate rocks. Ground-water levels in the Diamond Valley flow system have changed during the past 40 years. These changes are the result of pumpage for irrigation, municipal, domestic, and mining uses, mostly in southern Diamond Valley, and annual and longer-term variations in precipitation in undeveloped parts of the study area. A large area of ground-water decline that underlies an area about 10 miles wide and 20 miles long has developed in the basin-fill aquifer of southern Diamond Valley. Water levels beneath the main part of the irrigated area have declined as much as 90 feet. In undeveloped parts of the study area, annual water-level fluctuations generally have been no more than a few feet.

An Improved Model for a Once-through Counter-Cross-Flow Waste Heat Recovery Unit

DTIC Science & Technology

1983-09-01

RAnkine Cycle Energy Recovery (RACER) system. As conceived, the RACER system will be an unfired waste heat recovery system designed to convert waste... heater to arrive at the feedwater inlet. For the given geometry and flow conditions, the model will calcu- late the water inlet temperature consistent...when given feedwater inlet temperature, steam outlet tempera- ture, operating pressure, inlet and outlet gas conditions and gas flow rate. In this

Comparison of short-term chronic and chronic silver toxicity to fathead minnows in unamended and sodium chloride-amended waters.

PubMed

Naddy, Rami B; Rehner, Anita B; McNerney, Gina R; Gorsuch, Joseph W; Kramer, James R; Wood, Chris M; Paquin, Paul R; Stubblefield, William A

2007-09-01

The chronic (early life stage [ELS]) and short-term chronic (STC) toxicity of silver (as silver nitrate) to fathead minnows (FHM) was determined concurrently in flow-through exposures (33 volume additions/d). Paired ELS (approximately 30 d) and STC (7 d) studies were conducted with and without the addition of 60 mg/L Cl (as NaCl). The paired studies in unamended water were later repeated using standard flow conditions (9 volume additions/d). The purpose of the paired studies was to determine if short-term chronic endpoints can be used to predict effects in ELS studies. For each experiment, a "split-chamber" design (organisms were held in a common exposure chamber) allowed the direct comparison between short-term and chronic exposures. It appeared that the chronic toxicity of silver was mitigated to some extent by NaCl addition. The maximum acceptable toxicant concentration for growth in the ELS study was 0.53 microg dissolved Ag/L under standard flow conditions. Early life stage and STC endpoints in all three studies typically agreed within a factor of two. Whole-body sodium and silver concentrations measured in individual fathead minnows during these studies showed an increase in silver body burdens and a decrease in sodium concentration. These results indicate that the STC study could be used as a surrogate test to estimate chronic toxicity and that the mechanism of chronic silver toxicity may be the same as for acute toxicity.

Emergency core cooling system

DOEpatents

Schenewerk, William E.; Glasgow, Lyle E.

1983-01-01

A liquid metal cooled fast breeder reactor provided with an emergency core cooling system includes a reactor vessel which contains a reactor core comprising an array of fuel assemblies and a plurality of blanket assemblies. The reactor core is immersed in a pool of liquid metal coolant. The reactor also includes a primary coolant system comprising a pump and conduits for circulating liquid metal coolant to the reactor core and through the fuel and blanket assemblies of the core. A converging-diverging venturi nozzle with an intermediate throat section is provided in between the assemblies and the pump. The intermediate throat section of the nozzle is provided with at least one opening which is in fluid communication with the pool of liquid sodium. In normal operation, coolant flows from the pump through the nozzle to the assemblies with very little fluid flowing through the opening in the throat. However, when the pump is not running, residual heat in the core causes fluid from the pool to flow through the opening in the throat of the nozzle and outwardly through the nozzle to the assemblies, thus providing a means of removing decay heat.

The influence of pH on biotite dissolution and alteration kinetics at low temperature

USGS Publications Warehouse

Acker, James G.; Bricker, O.P.

1992-01-01

Biotite dissolution rates in acidic solutions were determined in fluidized-bed reactors and flowthrough columns. Biotite dissolution rates increased inversely as a linear function of pH in the pH range 3-7, where the rate order n = -0.34. Biotite dissolved incongruently over this pH range, with preferential release of magnesium and iron from the octahedral layer. Release of tetrahedral silicon was much greater at pH 3 than at higher pH. Iron release was significantly enhanced by low pH conditions. Solution compositions from a continuous exposure flow-through column of biotite indicated biotite dissolves incongruently at pH 4, consistent with alteration to a vermiculite-type product. Solution compositions from a second intermittent-flow column exhibited elevated cation release rates upon the initiation of each exposure to solution. The presence of strong oxidizing agents, the mineral surface area, and sample preparation methodology also influenced the dissolution or alteration kinetics of biotite. ?? 1992.

Effect of high altitude exposure on the hemodynamics of the bidirectional Glenn physiology: modeling incremented pulmonary vascular resistance and heart rate.

PubMed

Vallecilla, Carolina; Khiabani, Reza H; Sandoval, Néstor; Fogel, Mark; Briceño, Juan Carlos; Yoganathan, Ajit P

2014-06-03

The considerable blood mixing in the bidirectional Glenn (BDG) physiology further limits the capacity of the single working ventricle to pump enough oxygenated blood to the circulatory system. This condition is exacerbated under severe conditions such as physical activity or high altitude. In this study, the effect of high altitude exposure on hemodynamics and ventricular function of the BDG physiology is investigated. For this purpose, a mathematical approach based on a lumped parameter model was developed to model the BDG circulation. Catheterization data from 39 BDG patients at stabilized oxygen conditions was used to determine baseline flows and pressures for the model. The effect of high altitude exposure was modeled by increasing the pulmonary vascular resistance (PVR) and heart rate (HR) in increments up to 80% and 40%, respectively. The resulting differences in vascular flows, pressures and ventricular function parameters were analyzed. By simultaneously increasing PVR and HR, significant changes (p <0.05) were observed in cardiac index (11% increase at an 80% PVR and 40% HR increase) and pulmonary flow (26% decrease at an 80% PVR and 40% HR increase). Significant increase in mean systemic pressure (9%) was observed at 80% PVR (40% HR) increase. The results show that the poor ventricular function fails to overcome the increased preload and implied low oxygenation in BDG patients at higher altitudes, especially for those with high baseline PVRs. The presented mathematical model provides a framework to estimate the hemodynamic performance of BDG patients at different PVR increments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quantitative, depth-resolved determination of particle motion using multi-exposure, spatial frequency domain laser speckle imaging.

PubMed

Rice, Tyler B; Kwan, Elliott; Hayakawa, Carole K; Durkin, Anthony J; Choi, Bernard; Tromberg, Bruce J

2013-01-01

Laser Speckle Imaging (LSI) is a simple, noninvasive technique for rapid imaging of particle motion in scattering media such as biological tissue. LSI is generally used to derive a qualitative index of relative blood flow due to unknown impact from several variables that affect speckle contrast. These variables may include optical absorption and scattering coefficients, multi-layer dynamics including static, non-ergodic regions, and systematic effects such as laser coherence length. In order to account for these effects and move toward quantitative, depth-resolved LSI, we have developed a method that combines Monte Carlo modeling, multi-exposure speckle imaging (MESI), spatial frequency domain imaging (SFDI), and careful instrument calibration. Monte Carlo models were used to generate total and layer-specific fractional momentum transfer distributions. This information was used to predict speckle contrast as a function of exposure time, spatial frequency, layer thickness, and layer dynamics. To verify with experimental data, controlled phantom experiments with characteristic tissue optical properties were performed using a structured light speckle imaging system. Three main geometries were explored: 1) diffusive dynamic layer beneath a static layer, 2) static layer beneath a diffuse dynamic layer, and 3) directed flow (tube) submerged in a dynamic scattering layer. Data fits were performed using the Monte Carlo model, which accurately reconstructed the type of particle flow (diffusive or directed) in each layer, the layer thickness, and absolute flow speeds to within 15% or better.

A modular Human Exposure Model (HEM) framework to ...

EPA Pesticide Factsheets

Life Cycle Impact Analysis (LCIA) has proven to be a valuable tool for systematically comparing processes and products, and has been proposed for use in Chemical Alternatives Analysis (CAA). The exposure assessment portion of the human health impact scores of LCIA has historically focused on far-field sources (environmentally mediated exposures) while research has shown that use related exposures, (near-field exposures) typically dominate population exposure. Characterizing the human health impacts of chemicals in consumer products over the life cycle of these products requires an evaluation of both near-field as well far-field sources. Assessing the impacts of the near-field exposures requires bridging the scientific and technical gaps that currently prevent the harmonious use of the best available methods and tools from the fields of LCIA and human health exposure and risk assessment. The U.S. EPA’s Chemical Safety and Sustainability LC-HEM project is developing the Human Exposure Model (HEM) to assess near-field exposures to chemicals that occur to various populations over the life cycle of a commercial product. The HEM will be a publically available, web-based, modular system which will allow for the evaluation of chemical/product impacts in a LCIA framework to support CAA. We present here an overview of the framework for the modular HEM system. The framework includes a data flow diagram of in-progress and future planned modules, the definition of each mod

Images and Spectra of Time Dependent Two Component Advective Flow in Presence of Outflows

NASA Astrophysics Data System (ADS)

Chatterjee, Arka; Chakrabarti, Sandip K.; Ghosh, Himadri; Garain, Sudip K.

2018-05-01

Two Component Advective Flow (TCAF) successfully explains the spectral and temporal properties of outbursting or persistent sources. Images of static TCAF with Compton cloud or CENtrifugal pressure supported Boundary Layer (CENBOL) due to gravitational bending of photons have been studied before. In this paper, we study time dependent images of advective flows around a Schwarzschild black hole which include cooling effects due to Comptonization of soft photons from a Keplerian disks well as the self-consistently produced jets and outflows. We show the overall image of the disk-jet system after convolving with a typical beamwidth. A long exposure image with time dependent system need not show the black hole horizon conspicuously, unless one is looking at a soft state with no jet or the system along the jet axis. Assuming these disk-jet configurations are relevant to radio emitting systems also, our results would be useful to look for event horizons in high accretion rate Supermassive Black Holes in Seyfert galaxies, RL Quasars.

Experimental Testing and Modeling of a Pneumatic Regolith Delivery System for ISRU

NASA Technical Reports Server (NTRS)

Santiago-Maldonado, Edgardo; Dominquez, Jesus A.; Mantovani, James G.

2011-01-01

Excavating and transporting planetary regolith are examples of surface activities that may occur during a future space exploration mission to a planetary body. Regolith, whether it is collected on the Moon, Mars or even an asteroid, consists of granular minerals, some of which have been identified to be viable resources that can be mined and processed chemically to extract useful by-products, such as oxygen, water, and various metals and metal alloys. Even the depleted "waste" material from such chemical processes may be utilized later in the construction of landing pads and protective structures at the site of a planetary base. One reason for excavating and conveying planetary regolith is to deliver raw regolith material to in-situ resource utilization (ISRU) systems. The goal of ISRU is to provide expendable supplies and materials at the planetary destination, if possible. An in-situ capability of producing mission-critical substances such as oxygen will help to extend the mission and its success, and will greatly lower the overall cost of a mission by either eliminating, or significantly reducing, the need to transport the same expendable materials from the Earth. In order to support the goals and objectives of present and future ISRU projects, NASA seeks technology advancements in the areas of regolith conveying. Such systems must be effective, efficient and provide reliable performance over long durations while being exposed to the harsh environments found on planetary surfaces. These conditions include contact with very abrasive regolith particulates, exposure to high vacuum or dry (partial) atmospheres, wide variations in temperature, reduced gravity, and exposure to space radiation. Regolith conveying techniques that combine reduced failure modes and low energy consumption with high material transfer rates will provide significant value for future space exploration missions to the surfaces of the moon, Mars and asteroids. Pneumatic regolith conveying has demonstrated itself to be a viable delivery system through testing under terrestrial and reduced gravity conditions in recent years. Modeling and experimental testing have been conducted at NASA Kennedy Space Center to study and advance pneumatic planetary regolith delivery systems in support of NASA's ISRU project. The goal of this work is to use the model to predict solid-gas flow patterns in reduced gravity environments for ISRU inlet gas line allowing the eductor inlet gas flow to vary and depend on the flow pattern developed at the eductor as inferred by the experimental observations.

A Student Diffusion Activity

ERIC Educational Resources Information Center

Kutzner, Mickey; Pearson, Bryan

2017-01-01

Diffusion is a truly interdisciplinary topic bridging all areas of STEM education. When biomolecules are not being moved through the body by fluid flow through the circulatory system or by molecular motors, diffusion is the primary mode of transport over short distances. The direction of the diffusive flow of particles is from high concentration…

Optimal-mass-transfer-based estimation of glymphatic transport in living brain

NASA Astrophysics Data System (ADS)

Ratner, Vadim; Zhu, Liangjia; Kolesov, Ivan; Nedergaard, Maiken; Benveniste, Helene; Tannenbaum, Allen

2015-03-01

It was recently shown that the brain-wide cerebrospinal fluid (CSF) and interstitial fluid exchange system designated the `glymphatic pathway' plays a key role in removing waste products from the brain, similarly to the lymphatic system in other body organs . It is therefore important to study the flow patterns of glymphatic transport through the live brain in order to better understand its functionality in normal and pathological states. Unlike blood, the CSF does not flow rapidly through a network of dedicated vessels, but rather through para-vascular channels and brain parenchyma in a slower time-domain, and thus conventional fMRI or other blood-flow sensitive MRI sequences do not provide much useful information about the desired flow patterns. We have accordingly analyzed a series of MRI images, taken at different times, of the brain of a live rat, which was injected with a paramagnetic tracer into the CSF via the lumbar intrathecal space of the spine. Our goal is twofold: (a) find glymphatic (tracer) flow directions in the live rodent brain; and (b) provide a model of a (healthy) brain that will allow the prediction of tracer concentrations given initial conditions. We model the liquid flow through the brain by the diffusion equation. We then use the Optimal Mass Transfer (OMT) approach to derive the glymphatic flow vector field, and estimate the diffusion tensors by analyzing the (changes in the) flow. Simulations show that the resulting model successfully reproduces the dominant features of the experimental data. Keywords: inverse problem, optimal mass transport, diffusion equation, cerebrospinal fluid flow in brain, optical flow, liquid flow modeling, Monge Kantorovich problem, diffusion tensor estimation

Heterogeneity of Multimedia Exposures to Neurotoxic Elements (Al, As, Cd, Pb, Mn, and Hg) in Breastfed Infants from Porto Velho, Brazil.

PubMed

Bastos, Wanderley R; Vieira, Solange M; Manzatto, Ângelo G; Dórea, José G; Rubira, Marcelo C; de Souza, Victor Francisco P; da Costa Junior, Walkimar A; Souza Bastos, Maria T

2017-10-01

Infant exposure to neurotoxic elements is a public health issue that needs monitoring with regard to breast milk composition. We studied six neurotoxic elements in breast milk samples at different stages of lactation in mothers from Porto Velho, Brazil. We used a flow-injection mercury system (FIMS) to determine total Hg concentrations and an inductively coupled plasma optical emission spectrometer (ICP-OES) to determine the concentrations of Al, As, Cd, Pb, and Mn in 106 donors of a human milk bank. Association rules analyses were applied to determine the pattern of binary and ternary mixtures of the measured exposants. The metal concentration was mostly below the limit of detection (LOD) for Cd (99%), Pb (84%), and Hg (72%), and it was above the LOD for As (53%), Mn (60%), and Al (82%), respectively. Median concentrations (dry weight) of Al, As, Hg, Mn, and Pb were 1.81 μg/g, 13.8 ng/g, 7.1 ng/g, 51.1 ng/g, and 0.43 μg/g, respectively. Al is singly the most frequent element to which infants are exposed. Occurring binary combination (> LOD) was 56% for Al-Mn, 41% for Al-As, 22% for Al-Hg, and 13% for Al-Pb. In 100% of neonates, exposure to Al-ethylmercury (EtHg) occurred through immunization with thimerosal-containing vaccines (TCV). Association rules analysis revealed that Al was present in all of the multilevel combinations and hierarchical levels and that it showed a strong link with other neurotoxic elements (especially with Mn, As, and Hg). (a) Nursing infants are exposed to combinations of neurotoxicants by different routes, dosages, and at different stages of development; (b) In breastfed infants, the binary exposures to Al and total Hg can occur through breast milk and additionally through TCV (EtHg and Al); (c) The measured neurotoxic elements were found at low frequencies in breast milk and at concentrations that pose no public health concerns for milk banking.

Optimal-mass-transfer-based estimation of glymphatic transport in living brain.

PubMed

Ratner, Vadim; Zhu, Liangjia; Kolesov, Ivan; Nedergaard, Maiken; Benveniste, Helene; Tannenbaum, Allen

2015-02-21

It was recently shown that the brain-wide cerebrospinal fluid (CSF) and interstitial fluid exchange system designated the 'glymphatic pathway' plays a key role in removing waste products from the brain, similarly to the lymphatic system in other body organs 1,2 . It is therefore important to study the flow patterns of glymphatic transport through the live brain in order to better understand its functionality in normal and pathological states. Unlike blood, the CSF does not flow rapidly through a network of dedicated vessels, but rather through para-vascular channels and brain parenchyma in a slower time-domain, and thus conventional fMRI or other blood-flow sensitive MRI sequences do not provide much useful information about the desired flow patterns. We have accordingly analyzed a series of MRI images, taken at different times, of the brain of a live rat, which was injected with a paramagnetic tracer into the CSF via the lumbar intrathecal space of the spine. Our goal is twofold: (a) find glymphatic (tracer) flow directions in the live rodent brain; and (b) provide a model of a (healthy) brain that will allow the prediction of tracer concentrations given initial conditions. We model the liquid flow through the brain by the diffusion equation. We then use the Optimal Mass Transfer (OMT) approach 3 to derive the glymphatic flow vector field, and estimate the diffusion tensors by analyzing the (changes in the) flow. Simulations show that the resulting model successfully reproduces the dominant features of the experimental data.

Critical care nursing: Embedded complex systems.

PubMed

Trinier, Ruth; Liske, Lori; Nenadovic, Vera

2016-01-01

Variability in parameters such as heart rate, respiratory rate and blood pressure defines healthy physiology and the ability of the person to adequately respond to stressors. Critically ill patients have lost this variability and require highly specialized nursing care to support life and monitor changes in condition. The critical care environment is a dynamic system through which information flows. The critical care unit is typically designed as a tree structure with generally one attending physician and multiple nurses and allied health care professionals. Information flow through the system allows for identification of deteriorating patient status and timely interventionfor rescue from further deleterious effects. Nurses provide the majority of direct patient care in the critical care setting in 2:1, 1:1 or 1:2 nurse-to-patient ratios. The bedside nurse-critically ill patient relationship represents the primary, real-time feedback loop of information exchange, monitoring and treatment. Variables that enhance information flow through this loop and support timely nursing intervention can improve patient outcomes, while barriers can lead to errors and adverse events. Examining patient information flow in the critical care environment from a dynamic systems perspective provides insights into how nurses deliver effective patient care and prevent adverse events.

Experimental and analytical studies of flow through a ventral and axial exhaust nozzle system for STOVL aircraft

NASA Technical Reports Server (NTRS)

Esker, Barbara S.; Debonis, James R.

1991-01-01

Flow through a combined ventral and axial exhaust nozzle system was studied experimentally and analytically. The work is part of an ongoing propulsion technology effort at NASA Lewis Research Center for short takeoff, vertical landing (STOVL) aircraft. The experimental investigation was done on the NASA Lewis Powered Lift Facility. The experiment consisted of performance testing over a range of tailpipe pressure ratios from 1 to 3.2 and flow visualization. The analytical investigation consisted of modeling the same configuration and solving for the flow using the PARC3D computational fluid dynamics program. The comparison of experimental and analytical results was very good. The ventral nozzle performance coefficients obtained from both the experimental and analytical studies agreed within 1.2 percent. The net horizontal thrust of the nozzle system contained a significant reverse thrust component created by the flow overturning in the ventral duct. This component resulted in a low net horizontal thrust coefficient. The experimental and analytical studies showed very good agreement in the internal flow patterns.

Segmented heat exchanger

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

Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron

2010-12-14

A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least amore » portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.« less

Behind the scene with the fathead team: Part II. In-lab flow through exposures and “omics” to complement effects based monitoring in the Duluth-Superior Harbor.

EPA Science Inventory

As part of a research team focused on aquatic toxicity testing using fathead minnows as a model species, this presentation is the second of a three-part series, giving an overview of the types of field and laboratory studies as well as sample processing our team conducts at the U...

Evaluation of strobe lights to reduce turbine entrainment of juvenile steelhead (Oncorhynchus mykiss) at Cowlitz Falls Dam, Washington

USGS Publications Warehouse

Kock, Tobias J.; Evans, Scott D.; Liedtke, Theresa L.; Rondorf, Dennis W.; Kohn, Mike

2009-01-01

We conducted a radiotelemetry evaluation to determine if strobe lights could be used to decrease turbine entrainment of juvenile steelhead (Oncorhynchus mykiss) at Cowlitz Falls Dam, Washington. We found that radio-tagged juvenile steelhead approached and entered two spillbays (one lighted, one unlighted) in equal proportions. However, the presence of strobe lights was associated with decreased spillbay residence time of juvenile steelhead and increased passage through induction slots (secondary turbine intakes located upstream of the ogee on the spillway). Mean residence time of tagged fish inside the lighted spillbay was 14 min compared to 62 min inside the unlighted spillbay. Radio-tagged steelhead passed through induction slots at a higher proportion in the lighted spillbay (55%) than in the unlighted spillbay (26%). Recent studies have suggested that strobe lights can induce torpor in juvenile salmonids. We believe that strobe light exposure affected fish in our study at a location where they were susceptible to high flows thereby reducing mean residence time and increasing the proportion of tagged fish entering induction slots in the lighted spillbay. Our results suggest that factors such as deployment location, exposure, and flow are important variables that should be considered when evaluating strobe lights as a potential fish-deterring management tool.

Flow cytometry, morphometry and histopathology as biomarkers of benzo[a]pyrene exposure in brown bullheads (ameiurus nebulosus)

USGS Publications Warehouse

Grady, Andrew W.; McLaughlin, Ronald M.; Caldwell, Charles W.; Schmitt, Christopher J.; Stalling, David L.

1992-01-01

Brown bullheads were given a single intraperitoneal dose of 0, 5, 25 or 125 mg kg−1 benzo[a]pyrene (BaP), a carcinogenic polycyclic aromatic hydrocarbon, and evaluated over 18 months. Flow cytometric analyses of hepatocyte DNA content indicated an increase in DNA synthesis in BaP-exposed fish prior to day 14 post-exposure. Thereafter, all flow cytometric variables returned to initial levels. Histopathological evaluation of livers from fish sampled at 18 months revealed significant differences among treatments in the amount of hepatic macrophage ceroid pigmentation and basophilic staining intensity. No neoplasms or changes in blood cell DNA content were detected. Significant morphometric variations existed among fish, but differences between sexes overshadowed differences attributable to dose. Flow cytometry yielded no evidence of long-term DNA alterations from a single exposure to BaP; however, the differences detected by DNA analysis shortly after the toxic event suggest that flow cytometric cell cycle analysis may be useful for documenting continuing exposures.

Admitting Syrian Refugees: Is The Threat of Islamic State Infiltration Justified

DTIC Science & Technology

2017-06-01

operatives through electronic media , and risking exposure during the vetting process is unnecessary when easier means of access are available. 14...refugee program are unrealistic. The Islamic State recruits Western operatives through electronic media , and risking exposure during the vetting...Treasury Enforcement Communications System UNHCR United Nations High Commissioner for Refugees USCIS United States Citizenship and Immigration

A method of calibrating wind velocity sensors with a modified gas flow calibrator

NASA Technical Reports Server (NTRS)

Stump, H. P.

1978-01-01

A procedure was described for calibrating air velocity sensors in the exhaust flow of a gas flow calibrator. The average velocity in the test section located at the calibrator exhaust was verified from the mass flow rate accurately measured by the calibrator's precision sonic nozzles. Air at elevated pressures flowed through a series of screens, diameter changes, and flow straighteners, resulting in a smooth flow through the open test section. The modified system generated air velocities of 2 to 90 meters per second with an uncertainty of about two percent for speeds below 15 meters per second and four percent for the higher speeds. Wind tunnel data correlated well with that taken in the flow calibrator.

Ground-water flow in the New Jersey Coastal Plain

USGS Publications Warehouse

Martin, Mary

1998-01-01

Ground-water flow in 10 aquifers and 9 intervening confining units of the New Jersey Coastal Plain was simulated as part of the Regional Aquifer System Analysis. Data on aquifer and confining unit characteristics and on pumpage and water levels from 1918 through 1980 were incorporated into a multilayer finite-difference model. The report describes the conceptual hydrogeologic model of the unstressed flow systems, the methods and approach used in simulating flow, and the results of the simulations.

Microfluidic Device for Sequential Injection and Flushing of Solutions and its Application to Immunosensing

NASA Astrophysics Data System (ADS)

Nashida, Norihiro; Suzuki, Hiroaki

A microfluidic system with injecting and flushing functions was developed. In the system, hydrophilic flow channels have a dry-film photoresist layer which facilitates the introduction of solutions from four injection ports. The injection and flushing of solutions are controlled by valves operated by electrowetting. The valves consist of gold working electrodes in the flow channels or a through-hole in the glass substrate. Solutions can be sequentially introduced through the injection ports into a reaction chamber and flushed through a valve in the through-hole. Necessary immunoassay steps can be conducted on the chip, and a target antibody can be detected electrochemically.

Design and Modeling of a Liquid Lithium LiMIT Loop

NASA Astrophysics Data System (ADS)

Szott, Matthew; Christenson, Michael; Stemmley, Steven; Ahn, Chisung; Andruczyk, Daniel; Ruzic, David

2017-10-01

The use of flowing liquid lithium in plasma facing components has been shown to reduce erosion and thermal stress damage, prolong device lifetime, decrease edge recycling, reduce impurities, and increase plasma performance, all while providing a clean and self-healing surface. The Liquid Metal Infused Trench (LiMIT) system has proven the concept of controlled thermoelectric magnetohydrodynamic-driven lithium flow for use in fusion relevant conditions, through tests at UIUC, HT-7, and Magnum PSI. As the use of liquid lithium in fusion devices progresses, emphasis must now be placed on full systems integration of flowing liquid metal concepts. The LiMIT system will be upgraded to include a full liquid lithium loop, which will pump lithium into the fusion device, utilize TEMHD to drive lithium through the vessel, and remove lithium for filtration and degassing. Flow control concepts recently developed at UIUC - including wetting control, dryout control, and flow velocity control - will be tested in conjunction in order to demonstrate a robust system. Lithium loop system requirements, designs, and modeling work will be presented, along with plans for installation and testing on the HIDRA device at UIUC. This work is supported by DOE/ALPS DE-FG02-99ER54515.

Effect of heat transfer on rotating electroosmotic flow through a micro-vessel: haemodynamical applications

NASA Astrophysics Data System (ADS)

Sinha, A.; Mondal, A.; Shit, G. C.; Kundu, P. K.

2016-08-01

This paper theoretically analyzes the heat transfer characteristics associated with electroosmotic flow of blood through a micro-vessel having permeable walls. The analysis is based on the Debye-Hückel approximation for charge distributions and the Navier-Stokes equations are assumed to represent the flow field in a rotating system. The velocity slip condition at the vessel walls is taken into account. The essential features of the rotating electroosmotic flow of blood and associated heat transfer characteristics through a micro-vessel are clearly highlighted by the variation in the non-dimensional flow velocity, volumetric flow rate and non-dimensional temperature profiles. Moreover, the effect of Joule heating parameter and Prandtl number on the thermal transport characteristics are discussed thoroughly. The study reveals that the flow of blood is appreciably influenced by the elctroosmotic parameter as well as rotating Reynolds number.

Reorganization of Ice Sheet Flow Patterns in Arctic Canada Prior to the Mid-Pleistocene Transition

NASA Astrophysics Data System (ADS)

Refsnider, K. A.; Miller, G. H.

2010-12-01

The Foxe sector of the Laurentide Ice Sheet (LIS) experienced a complex and dynamic interplay between cold-based, non-erosive ice on uplands, fast-moving outlet glaciers that carved deep fiords through the Arctic Cordillera, and even more erosive ice streams that occupied larger straits and sounds, transporting ice from the Foxe Dome to calving margins in Baffin Bay and the Labrador Sea. The high topography of Baffin Island forms a broad barrier to the flow of ice to these calving margins and gradually has been dissected since the onset of Northern Hemisphere glaciation. However, evidence for the evolution of LIS erosion and basal thermal regime patterns during successive glaciations is poorly preserved in the geologic record. We use a new approach utilizing published till geochemistry and cosmogenic radionuclide (CRN) data to constrain the development of the fiorded coastline and the distribution of cold-based ice across central Baffin Island in both spatial and temporal domains over many glacial-interglacial cycles. The combination of till geochemistry data, which is used to characterize till weathering, and modeled CRN burial-exposure histories provides strong evidence for a shift in basal thermal regimes across the interior plateaux of Baffin Island between 1.9 and 1.2 Ma. While it may be coincidence that this time interval abuts the onset of the mid-Pleistocene transition (MPT), it has been hypothesized that changes in subglacial conditions were potentially an important mechanism in altering LIS dynamics across the MPT. Prior to this time, ice was likely wet-based and erosive across the majority of the Baffin Island interior, but by 1.9-1.2 Ma, some parts of the landscape became perpetually covered by cold-based ice during glaciations, a pattern that persisted through the last glacial cycle. The modern fiord system also must have developed by this time, and preferential channeling of ice flow into major fiords may have been sufficient to effectively shut off ice flow across the landscape between outlet glaciers. These results imply that there was a major shift in the basal thermal regime across the northeastern LIS, and the subsequent expansion of cold-based ice and the concentration of ice flow in fewer outlet systems across this region may help explain the cause of the MPT from 41- to 100-kyr glacial cycles.

Iodine Hall Thruster Propellant Feed System for a CubeSat

NASA Technical Reports Server (NTRS)

Polzin, Kurt A.; Peeples, Steven

2014-01-01

The components required for an in-space iodine vapor-fed Hall effect thruster propellant management system are described. A laboratory apparatus was assembled and used to produce iodine vapor and control the flow through the application of heating to the propellant reservoir and through the adjustment of the opening in a proportional flow control valve. Changing of the reservoir temperature altered the flowrate on the timescale of minutes while adjustment of the proportional flow control valve changed the flowrate immediately without an overshoot or undershoot in flowrate with the requisite recovery time associated with thermal control systems. The flowrates tested spanned a range from 0-1.5 mg/s of iodine, which is sufficient to feed a 200-W Hall effect thruster.

Effects of developmental lead exposure on the hippocampal methylome: Influences of sex and timing and level of exposure.

PubMed

Singh, G; Singh, V; Wang, Zi-Xuan; Voisin, G; Lefebvre, F; Navenot, J-M; Evans, B; Verma, M; Anderson, D W; Schneider, J S

2018-06-15

Developmental lead (Pb) exposure results in persistent cognitive/behavioral impairments as well as an elevated risk for developing a variety of diseases in later life. Environmental exposures during development can result in a variety of epigenetic changes, including alterations in DNA methylation, that can influence gene expression patterns and affect the function and development of the nervous system. The present promoter-based methylation microarray profiling study explored the extent to which developmental Pb exposure may modify the methylome of a brain region, hippocampus, known to be sensitive to the effects of Pb exposure. Male and female Long Evans rats were exposed to 0 ppm, 150 ppm, 375 ppm, or 750 ppm Pb through perinatal exposures (gestation through lactation), early postnatal exposures (birth through weaning), or long-term postnatal exposures (birth through postnatal day 55). Results showed a significant contribution of sex to the hippocampal methylome and effects of Pb exposure level, with non-linear dose response effects on methylation. Surprisingly, the developmental period of exposure contributed only a small amount of variance to the overall data and gene ontology (GO) analysis revealed the largest number of overrepresented GO terms in the groups with the lowest level of exposure. The highest number of significant differentially methylated regions was found in females exposed to Pb at the lowest exposure level. Our data reinforce the significant effect that low level Pb exposure may have on gene-specific DNA methylation patterns in brain and that this occurs in a sex-dependent manner. Copyright © 2018 Elsevier B.V. All rights reserved.

Room air monitor for radioactive aerosols

DOEpatents

Balmer, D.K.; Tyree, W.H.

1987-03-23

A housing assembly for use with a room air monitor for simultaneous collection and counting of suspended particles includes a casing containing a combination detector-preamplifier system at one end, a filter system at the other end, and an air flow system consisting of an air inlet formed in the casing between the detector-preamplifier system and the filter system and an air passageway extending from the air inlet through the casing and out the end opposite the detector-preamplifier combination. The filter system collects suspended particles transported directly through the housing by means of the air flow system, and these particles are detected and examined for radioactivity by the detector-preamplifier combination. 2 figs.

Role of Autonomic Reflex Arcs in Cardiovascular Responses to Air Pollution Exposure

PubMed Central

Hazari, Mehdi S.; Farraj, Aimen K.

2016-01-01

The body responds to environmental stressors by triggering autonomic reflexes in the pulmonary receptors, baroreceptors, and chemoreceptors to maintain homeostasis. Numerous studies have shown that exposure to various gases and airborne particles can alter the functional outcome of these reflexes, particularly with respect to the cardiovascular system. Modulation of autonomic neural input to the heart and vasculature following direct activation of sensory nerves in the respiratory system, elicitation of oxidative stress and inflammation, or through other mechanisms is one of the primary ways that exposure to air pollution affects normal cardiovascular function. Any homeostatic process that utilizes the autonomic nervous system to regulate organ function might be affected. Thus, air pollution and other inhaled environmental irritants have the potential to alter both local airway function and baro-and chemoreflex responses, which modulate autonomic control of blood pressure and detect concentrations of key gases in the body. While each of these reflex pathways causes distinct responses, the systems are heavily integrated and communicate through overlapping regions of the brainstem to cause global effects. This short review summarizes the function of major pulmonary sensory receptors, baroreceptors, and carotid body chemoreceptors and discusses the impacts of air pollution exposure on these systems. PMID:25123706

Developmental cigarette smoke exposure II: Hippocampus proteome and metabolome profiles in adult offspring.

PubMed

Neal, Rachel E; Jagadapillai, Rekha; Chen, Jing; Webb, Cindy; Stocke, Kendall; Greene, Robert M; Pisano, M Michele

2016-10-01

Exposure to cigarette smoke during development is linked to neurodevelopmental delays and cognitive impairment including impulsivity, attention deficit disorder, and lower IQ. Utilizing a murine experimental model of "active" inhalation exposure to cigarette smoke spanning the entirety of gestation and through human third trimester equivalent hippocampal development [gestation day 1 (GD1) through postnatal day 21 (PD21)], we examined hippocampus proteome and metabolome alterations present at a time during which developmental cigarette smoke exposure (CSE)-induced behavioral and cognitive impairments are evident in adult animals from this model system. At six month of age, carbohydrate metabolism and lipid content in the hippocampus of adult offspring remained impacted by prior exposure to cigarette smoke during the critical period of hippocampal ontogenesis indicating limited glycolysis. These findings indicate developmental CSE-induced systemic glucose availability may limit both organism growth and developmental trajectory, including the capacity for learning and memory. Copyright © 2016 Elsevier Inc. All rights reserved.

Assessment of Quantum Dot Penetration into Skin in Different Species Under Different Mechanical Actions

NASA Astrophysics Data System (ADS)

Monteiro-Riviere, N. A.; Zhang, L. W.

Skin penetration is one of the major routes of exposure for nanoparticles to gain access to a biological system. QD nanoparticles have received a great deal of attention due to their fluorescent characteristics and potential use in medical applications. However, little is known about their permeability in skin. This study focuses on three types of quantum dots (QD) with different surface coatings and concentrations on their ability to penetrate skin. QD621 (polyethylene glycol coated, PEG) was studied for 24 h in porcine skin flow-through diffusion cells. QD565 and QD655 coated with carboxylic acid were studied for 8 and 24 h in flow-through diffusion cells with flexed, tape stripped and abraded rat skin to determine if these mechanical actions could perturb the barrier and affect penetration. Confocal microscopy depicted QD621 penetration through the uppermost layers of the stratum corneum (SC) and fluorescence was found in the SC and near hair follicles. QD621 were found in the intercellular lipid layers of the SC by transmission electron microscopy (TEM). QD565 and 655 with flexed and tape-stripped skin did not show penetration; only abraded skin showed penetration in the viable dermal layers. In all QD studies, inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis for cadmium (Cd) and fluorescence for QD did not detect Cd or fluorescence signal in the perfusate at any time point, concentration or type of QD. These results indicate that porcine skin penetration of QD621 is minimal and limited primarily to the outer SC layers, while QD565 and 655 penetrated into the dermis of abraded skin. The anatomical complexity of skin and species differences should be taken into consideration when selecting an animal model to study nanoparticle absorption/penetration. These findings are of importance to risk assessment for nanoscale materials because it indicates that if skin barrier is altered such as in wounds, scrapes, or dermatitis conditions could affect nanoparticle penetration deeper into the dermal layers and skin is an important organ and can serve as a potential route of exposure and should not be overlooked.

Reconstructing Magmatic-Hydrothermal Systems via Geologic Mapping of the Tilted, Cross-sectional Exposures of the Yerington District, Nevada

NASA Astrophysics Data System (ADS)

Dilles, J. H.; Proffett, J. M.

2011-12-01

The Jurassic Yerington batholith was cut by Miocene to recent normal faults and tilted ~90° west (Proffett, 1977). Exposures range from the volcanic environment to ~6 km depth in the batholith. Magmatic-hydrothermal fluids derived from the Luhr Hill granite and associated porphyry dikes produced characteristic porphyry copper mineralization and rock alteration (K-silicate, sericitic, and advanced argillic) in near-vertical columnar zones above cupolas on the deep granite. In addition, saline brines derived from the early Mesozoic volcanic and sedimentary section intruded by the batholith were heated and circulated through the batholith producing voluminous sodic-calcic and propylitic alteration. The magnetite-copper ore body at Pumpkin Hollow is hosted in early Mesozoic sedimentary rocks in the contact aureole of the batholith, and appears to be an IOCG type deposit produced where the sedimentary brines exited the batholith. Although many advances in understanding of Yerington have been made by lab-based geochronology and geochemistry studies, the first order igneous and hydrothermal features were recognized first in the 1960s and 1970s and are best documented by geological mapping at a variety of scales ranging from 1:500 to 1:24,000. The Anaconda technique of mapping mine benches, trenches, and drill cores was perfected here (Einaudi, 1997), and other techniques were used for surface exposures. The geologic and hydrothermal alteration maps establish that hydrothermal alteration accompanied each of several porphyry dike intrusions, and affected more than 100 km3 of rock. Both zonation in alteration mineralogy and vein orientations allow reconstruction of source areas and >5 km-long flow-paths of hydrothermal fluids through the batholith and contact aureole.

Intrinsically safe moisture blending system

DOEpatents

Hallman Jr., Russell L.; Vanatta, Paul D.

2012-09-11

A system for providing an adjustable blend of fluids to an application process is disclosed. The system uses a source of a first fluid flowing through at least one tube that is permeable to a second fluid and that is disposed in a source of the second fluid to provide the adjustable blend. The temperature of the second fluid is not regulated, and at least one calibration curve is used to predict the volumetric mixture ratio of the second fluid with the first fluid from the permeable tube. The system typically includes a differential pressure valve and a backpressure control valve to set the flow rate through the system.

Influence of metabolism in skin on dosimetry after topical exposure

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

Bronaugh, R.L.; Collier, S.W.; Macpherson, S.E.

1994-12-01

Metabolism of chemicals occurs in skin and therefore should be taken into account when one determines topical exposure dose. Skin metabolism is difficult to measure in vivo because biological specimens may also contain metabolites from other tissues. Metabolism in skin during percutaneous absorption can be studied with viable skin in flow-through diffusion cells. Several compounds metabolized by microsomal enzymes in skin (benzo[a]pyrene and 7-ethoxycoumarin) penetrated human and hairless guinea pig skin predominantly unmetabolized. However, compounds containing a primary amino group (p-aminobenzoic acid, benzocaine, and azo color reduction products) were substrates for acetyltransferase activity in skin and were substantially metabolized duringmore » absorption. A physiologically based pharmacokinetic model has been developed with an input equation, allowing modeling after topical exposure. 14 refs., 3 figs., 4 tabs.« less

Axial static mixer

DOEpatents

Sandrock, H.E.

1982-05-06

Static axial mixing apparatus includes a plurality of channels, forming flow paths of different dimensions. The axial mixer includes a flow adjusting device for adjustable selective control of flow resistance of various flow paths in order to provide substantially identical flows through the various channels, thereby reducing nonuniform coating of interior surfaces of the channels. The flow adjusting device may include diaphragm valves, and may further include a pressure regulating system therefor.

Personal medical electronic devices and walk-through metal detector security systems: assessing electromagnetic interference effects.

PubMed

Guag, Joshua; Addissie, Bisrat; Witters, Donald

2017-03-20

There have been concerns that Electromagnetic security systems such as walk-through metal detectors (WTMDs) can potentially cause electromagnetic interference (EMI) in certain active medical devices including implantable cardiac pacemakers and implantable neurostimulators. Incidents of EMI between WTMDs and active medical devices also known as personal medical electronic devices (PMED) continue to be reported. This paper reports on emission measurements of sample WTMDs and testing of 20 PMEDs in a WTMD simulation system. Magnetic fields from sample WTMD systems were characterized for emissions and exposure of certain PMEDs. A WTMD simulator system designed and evaluated by FDA in previous studies was used to mimic the PMED exposures to the waveform from sample WTMDs. The simulation system allows for controlled PMED exposure enabling careful study with adjustable magnetic field strengths and exposure duration, and provides flexibility for PMED exposure at elevated levels in order to study EMI effects on the PMED. The PMED samples consisted of six implantable cardiac pacemakers, six implantable cardioverter defibrillators (ICD), five implantable neurostimulators, and three insulin pumps. Each PMED was exposed in the simulator to the sample WTMD waveforms using methods based on appropriate consensus test standards for each of the device type. Testing the sample PMEDs using the WTMD simulator revealed EMI effects on two implantable pacemakers and one implantable neurostimulator for exposure field strength comparable to actual WTMD field strength. The observed effects were transient and the PMEDs returned to pre-exposure operation within a few seconds after removal from the simulated WTMD exposure fields. No EMI was observed for the sample ICDs or insulin pumps. The findings are consistent with earlier studies where certain sample PMEDs exhibited EMI effects. Clinical implications were not addressed in this study. Additional studies are needed to evaluate potential PMED EMI susceptibilities over a broader range of security systems.

Steroid Androgen Exposure during Development Has No Effect on Reproductive Physiology of Biomphalaria glabrata.

PubMed

Kaur, Satwant; Baynes, Alice; Lockyer, Anne E; Routledge, Edwin J; Jones, Catherine S; Noble, Leslie R; Jobling, Susan

2016-01-01

Gastropod mollusks have been proposed as alternative models for male reproductive toxicity testing, due to similarities in their reproductive anatomy compared to mammals, together with evidence that endocrine disrupting chemicals can cause effects in some mollusks analogous to those seen in mammals. To test this hypothesis, we used the freshwater pulmonate snail, Biomphalaria glabrata, for which various genetic tools and a draft genome have recently become available, to investigate the effects of two steroid androgens on the development of mollusk secondary sexual organs. Here we present the results of exposures to two potent androgens, the vertebrate steroid; 5α-dihydrotestosterone (DHT) and the pharmaceutical anabolic steroid; 17α-methyltestosterone (MT), under continuous flow-through conditions throughout embryonic development and up to sexual maturity. Secondary sexual gland morphology, histopathology and differential gene expression analysis were used to determine whether steroid androgens stimulated or inhibited organ development. No significant differences between tissues from control and exposed snails were identified, suggesting that these androgens elicited no biologically detectable response normally associated with exposure to androgens in vertebrate model systems. Identifying no effect of androgens in this mollusk is significant, not only in the context of the suitability of mollusks as alternative model organisms for testing vertebrate androgen receptor agonists but also, if applicable to other similar mollusks, in terms of the likely impacts of androgens and anti-androgenic pollutants present in the aquatic environment.

Steroid Androgen Exposure during Development Has No Effect on Reproductive Physiology of Biomphalaria glabrata

PubMed Central

Lockyer, Anne E.; Routledge, Edwin J.; Jones, Catherine S.; Noble, Leslie R.; Jobling, Susan

2016-01-01

Gastropod mollusks have been proposed as alternative models for male reproductive toxicity testing, due to similarities in their reproductive anatomy compared to mammals, together with evidence that endocrine disrupting chemicals can cause effects in some mollusks analogous to those seen in mammals. To test this hypothesis, we used the freshwater pulmonate snail, Biomphalaria glabrata, for which various genetic tools and a draft genome have recently become available, to investigate the effects of two steroid androgens on the development of mollusk secondary sexual organs. Here we present the results of exposures to two potent androgens, the vertebrate steroid; 5α-dihydrotestosterone (DHT) and the pharmaceutical anabolic steroid; 17α-methyltestosterone (MT), under continuous flow-through conditions throughout embryonic development and up to sexual maturity. Secondary sexual gland morphology, histopathology and differential gene expression analysis were used to determine whether steroid androgens stimulated or inhibited organ development. No significant differences between tissues from control and exposed snails were identified, suggesting that these androgens elicited no biologically detectable response normally associated with exposure to androgens in vertebrate model systems. Identifying no effect of androgens in this mollusk is significant, not only in the context of the suitability of mollusks as alternative model organisms for testing vertebrate androgen receptor agonists but also, if applicable to other similar mollusks, in terms of the likely impacts of androgens and anti-androgenic pollutants present in the aquatic environment. PMID:27448327

Method of controlling temperature of a thermoelectric generator in an exhaust system

DOEpatents

Prior, Gregory P; Reynolds, Michael G; Cowgill, Joshua D

2013-05-21

A method of controlling the temperature of a thermoelectric generator (TEG) in an exhaust system of an engine is provided. The method includes determining the temperature of the heated side of the TEG, determining exhaust gas flow rate through the TEG, and determining the exhaust gas temperature through the TEG. A rate of change in temperature of the heated side of the TEG is predicted based on the determined temperature, the determined exhaust gas flow rate, and the determined exhaust gas temperature through the TEG. Using the predicted rate of change of temperature of the heated side, exhaust gas flow rate through the TEG is calculated that will result in a maximum temperature of the heated side of the TEG less than a predetermined critical temperature given the predicted rate of change in temperature of the heated side of the TEG. A corresponding apparatus is provided.

Death Valley regional groundwater flow system, Nevada and California-Hydrogeologic framework and transient groundwater flow model

USGS Publications Warehouse

Belcher, Wayne R.; Sweetkind, Donald S.

2010-01-01

A numerical three-dimensional (3D) transient groundwater flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the groundwater flow system and previous less extensive groundwater flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect groundwater flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley regional groundwater flow system (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the groundwater flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural groundwater discharge occurring through evapotranspiration (ET) and spring flow; the history of groundwater pumping from 1913 through 1998; groundwater recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were provided by acquiring additional data, by reevaluating existing data using current technology and concepts, and by refining earlier interpretations to reflect the current understanding of the regional groundwater flow system. Groundwater flow in the Death Valley region is composed of several interconnected, complex groundwater flow systems. Groundwater flow occurs in three subregions in relatively shallow and localized flow paths that are superimposed on deeper, regional flow paths. Regional groundwater flow is predominantly through a thick Paleozoic carbonate rock sequence affected by complex geologic structures from regional faulting and fracturing that can enhance or impede flow. Spring flow and ET are the dominant natural groundwater discharge processes. Groundwater also is withdrawn for agricultural, commercial, and domestic uses. Groundwater flow in the DVRFS was simulated using MODFLOW-2000, the U.S. Geological Survey 3D finitedifference modular groundwater flow modeling code that incorporates a nonlinear least-squares regression technique to estimate aquifer parameters. The DVRFS model has 16 layers of defined thickness, a finite-difference grid consisting of 194 rows and 160 columns, and uniform cells 1,500 meters (m) on each side. Prepumping conditions (before 1913) were used as the initial conditions for the transient-state calibration. The model uses annual stress periods with discrete recharge and discharge components. Recharge occurs mostly from infiltration of precipitation and runoff on high mountain ranges and from a small amount of underflow from adjacent basins. Discharge occurs primarily through ET and spring discharge (both simulated as drains) and water withdrawal by pumping and, to a lesser amount, by underflow to adjacent basins simulated by constant-head boundaries. All parameter values estimated by the regression are reasonable and within the range of expected values. The simulated hydraulic heads of the final calibrated transient mode

Mercury flow through an Asian rice-based food web.

PubMed

Abeysinghe, Kasun S; Qiu, Guangle; Goodale, Eben; Anderson, Christopher W N; Bishop, Kevin; Evers, David C; Goodale, Morgan W; Hintelmann, Holger; Liu, Shengjie; Mammides, Christos; Quan, Rui-Chang; Wang, Jin; Wu, Pianpian; Xu, Xiao-Hang; Yang, Xiao-Dong; Feng, Xinbin

2017-10-01

Mercury (Hg) is a globally-distributed pollutant, toxic to humans and animals. Emissions are particularly high in Asia, and the source of exposure for humans there may also be different from other regions, including rice as well as fish consumption, particularly in contaminated areas. Yet the threats Asian wildlife face in rice-based ecosystems are as yet unclear. We sought to understand how Hg flows through rice-based food webs in historic mining and non-mining regions of Guizhou, China. We measured total Hg (THg) and methylmercury (MeHg) in soil, rice, 38 animal species (27 for MeHg) spanning multiple trophic levels, and examined the relationship between stable isotopes and Hg concentrations. Our results confirm biomagnification of THg/MeHg, with a high trophic magnification slope. Invertivorous songbirds had concentrations of THg in their feathers that were 15x and 3x the concentration reported to significantly impair reproduction, at mining and non-mining sites, respectively. High concentrations in specialist rice consumers and in granivorous birds, the later as high as in piscivorous birds, suggest rice is a primary source of exposure. Spiders had the highest THg concentrations among invertebrates and may represent a vector through which Hg is passed to vertebrates, especially songbirds. Our findings suggest there could be significant population level health effects and consequent biodiversity loss in sensitive ecosystems, like agricultural wetlands, across Asia, and invertivorous songbirds would be good subjects for further studies investigating this possibility. Copyright © 2017 Elsevier Ltd. All rights reserved.

Permeation Resistance of Chlorinated Polyethylene Against Hydrazine Fuels

NASA Technical Reports Server (NTRS)

Waller, J. M.; Williams, J. H.

1999-01-01

The permeation resistance of chlorinated polyethylene (CPE) used in chemical protective clothing against the aerospace fuels hydrazine, monomethylhydrazine (MMH), and uns-dimethylhydrazine (UDMH) was determined by measuring breakthrough times and time-averaged vapor transmission rates using an ASTM F 739 permeation cell. Two exposure scenarios were simulated: a 2 hour (h) fuel vapor exposure, and a liquid fuel "splash" followed by a 2 h vapor exposure. To simulate internal suit pressure during operation, a positive differential pressure of 0.3 in. water (75 Pa) on the collection side of the permeation apparatus was used. Breakthrough was observed after exposure to liquid MMH, and to vapor and liquid UDMH. No breakthrough was observed after exposure to vapor and liquid hydrazine, or vapor MMH. A model was then used to calculate propellant concentrations inside a totally encapsulating chemical protective suit based on the ASTM permeation data obtained in the present study. Concentrations were calculated under conditions of fixed vapor transmission rate, variable breathing air flow rate, and variable splash exposure area. Calculations showed that the maximum allowable permeation rates of hydrazine fuels through CPE were of the order of 0.05 to 0.08 ng sq cm/min for encapsulating suits with low breathing air flow rates (of the order of 5 scfm or 140 L/min). Above these permeation rates, the 10 parts per billion (ppb) threshold limit value time - weighted average could be exceeded for chemical protective suits having a CPE torso. To evaluate suit performance at ppb level concentrations, use of a sensitive analytical method such as cation exchange high performance liquid chromatography with amperometric detection was found to be essential.

Measurement of Flow Patterns and Dispersion in the Human Airways

NASA Astrophysics Data System (ADS)

Fresconi, Frank E.; Prasad, Ajay K.

2006-03-01

A detailed knowledge of the flow and dispersion within the human respiratory tract is desirable for numerous reasons. Both risk assessments of exposure to toxic particles in the environment and the design of medical delivery systems targeting both lung-specific conditions (asthma, cystic fibrosis, and chronic obstructive pulmonary disease (COPD)) and system-wide ailments (diabetes, cancer, hormone replacement) would profit from such an understanding. The present work features experimental efforts aimed at elucidating the fluid mechanics of the lung. Particle image velocimetry (PIV) and laser induced fluorescence (LIF) measurements of oscillatory flows were undertaken in anatomically accurate models (single and multi-generational) of the conductive region of the lung. PIV results captured primary and secondary velocity fields. LIF was used to determine the amount of convective dispersion across an individual generation of the lung.

Effect of streptavidin-biotin on endothelial vasoregulation and leukocyte adhesion.

PubMed

Chan, Bernard P; Reichert, William M; Truskey, George A

2004-08-01

The current study examines whether the adhesion promoting arginine-glycine-aspartate-streptavidin mutant (RGD-SA) also affects two important endothelial cell (EC) functions in vitro: vasoregulation and leukocyte adhesion. EC adherent to surfaces via fibronectin (Fn) or Fn plus RGD-SA were subjected to laminar shear flow and media samples were collected over a period of 4h to measure the concentration of nitric oxide (NO), prostacyclin (PGI(2)), and endothelin-1 (ET-1). Western blot analysis was used to quantify the levels of endothelial-derived nitric oxide synthase (eNOS) and cyclooxygenase II (COX II). In a separate set of experiments, fluorescent polymorphonuclear leukocyte (PMN) adhesion to EC was quantified for EC with and without exposure to flow preconditioning. When cell adhesion was supplemented with the SA-biotin system, flow-induced production of NO and PGI(2) increased significantly relative to cells adherent on Fn alone. Previous exposure of EC to shear flow also significantly decreased PMN attachment to SA-biotin supplemented EC, but only after 2h of exposure to shear flow. The observed decrease in PMN-EC adhesion was negated by NG-nitro-L-arginine methyl ester (L-NAME), an antagonist of NO synthesis, but not by indomethacin, an inhibitor to PGI(2) synthesis, indicating the induced effect of PMN-EC interaction is primarily NO-dependent. Results from this study suggest that the use of SA-biotin to supplement EC adhesion encourages vasodilation and PMN adhesion in vitro under physiological shear-stress conditions. We postulate that the presence of SA-biotin more efficiently transmits the shear-stress signal and amplifies the downstream events including the NO and PGI(2) release and leukocyte-EC inhibition. These results may have ramifications for reducing thrombus-induced vascular graft failure.

Detection of early changes in lung-cell cytology by flow-systems analysis techniques. Progress report, January 1--June 30, 1976

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

Steinkamp, J. A.; Hansen, K. M.; Wilson, J. S.

1976-08-01

This report summarizes results of preliminary experiments to develop cytological and biochemical indicators for estimating damage to respiratory epithelium exposed to toxic agents associated with the by-products of nonnuclear energy production using advanced flow-systems cell-analysis technologies. Since initiation of the program one year ago, progress has been made in obtaining adequate numbers of exfoliated lung cells from the Syrian hamster for flow analysis; cytological techniques developed on human exfoliated gynecological samples have been adapted to hamster lung epithelium for obtaining single-cell suspensions; and lung-cell samples have been initially characterized based on DNA content, total protein, nuclear and cytoplasmic size, andmore » multiangle light-scatter measurements. Preliminary results from measurements of the above parameters which recently became available are described in this report. As the flow-systems technology is adapted further to analysis of exfoliated lung cells, measurements of changes in physical and biochemical cellular properties as a function of exposure to toxic agents will be performed.« less

Confined Floodplain Dynamics on Semi-Arid Systems

NASA Astrophysics Data System (ADS)

Entwistle, N. S.

2017-12-01

Many watercourses across southern Africa are characterised by a bedrock influenced `macro-channel' created as a result of geologically recent fluvial incision into ancient planation surfaces. The rivers of the Kruger National Park in Mpumalanga Province, South Africa are no exception, displaying a varied set of channel types within a bedrock template. Contemporary flows are largely contained within the confines of this `macro-channel' and a diverse valley bottom morphology and ecology has developed in response to this flow regime coupled with intermittent fine sediment delivery from the catchment. Aerial imagery and field monitoring of the impact of two cyclone driven extreme flows and subsequent recovery phases suggests that flood impact is spatially variable with bedrock exposure greatest along watercourses already severely impacted by previous events. Subsequent system development has been characterised by the redistribution and vegetative colonisation of unconsolidated sandy sediment over bedrock. On less impacted systems vegetative induced recovery has, in contrast, been rapid with many of the species present displaying significant resilience to extreme flows forming residual pockets which are subsequently developing alongside embryonic morphologic recovery. Using these observations a model of valley bottom recovery is presented.

Personal exposure to dust and endotoxin in Robusta and Arabica coffee processing factories in Tanzania.

PubMed

Sakwari, Gloria; Mamuya, Simon H D; Bråtveit, Magne; Larsson, Lennart; Pehrson, Christina; Moen, Bente E

2013-03-01

Endotoxin exposure associated with organic dust exposure has been studied in several industries. Coffee cherries that are dried directly after harvest may differ in dust and endotoxin emissions to those that are peeled and washed before drying. The aim of this study was to measure personal total dust and endotoxin levels and to evaluate their determinants of exposure in coffee processing factories. Using Sidekick Casella pumps at a flow rate of 2l/min, total dust levels were measured in the workers' breathing zone throughout the shift. Endotoxin was analyzed using the kinetic chromogenic Limulus amebocyte lysate assay. Separate linear mixed-effects models were used to evaluate exposure determinants for dust and endotoxin. Total dust and endotoxin exposure were significantly higher in Robusta than in Arabica coffee factories (geometric mean 3.41 mg/m(3) and 10 800 EU/m(3) versus 2.10 mg/m(3) and 1400 EU/m(3), respectively). Dry pre-processed coffee and differences in work tasks explained 30% of the total variance for total dust and 71% of the variance for endotoxin exposure. High exposure in Robusta processing is associated with the dry pre-processing method used after harvest. Dust and endotoxin exposure is high, in particular when processing dry pre-processed coffee. Minimization of dust emissions and use of efficient dust exhaust systems are important to prevent the development of respiratory system impairment in workers.

NEURODEVELOPMENTAL EFFECTS OF ENVIRONMENTAL EXPOSURES

EPA Science Inventory

Neurodevelopmental Effects of Environmental Exposures
Sherry G. Selevan, Pauline Mendola, Deborah C. Rice (US EPA, Washington,
DC)

The nervous system starts development early in gestation and continues to develop through adolescence. Thus, critical windows of vuln...

Exposure to ultrafine particles, intracellular production of reactive oxygen species in leukocytes and altered levels of endothelial progenitor cells.

PubMed

Jantzen, Kim; Møller, Peter; Karottki, Dorina Gabriela; Olsen, Yulia; Bekö, Gabriel; Clausen, Geo; Hersoug, Lars-Georg; Loft, Steffen

2016-06-01

Exposure to particles in the fine and ultrafine size range has been linked to induction of low-grade systemic inflammation, oxidative stress and development of cardiovascular diseases. Declining levels of endothelial progenitor cells within systemic circulation have likewise been linked to progression of cardiovascular diseases. The objective was to determine if exposure to fine and ultrafine particles from indoor and outdoor sources, assessed by personal and residential indoor monitoring, is associated with altered levels of endothelial progenitor cells, and whether such effects are related to leukocyte-mediated oxidative stress. The study utilized a cross sectional design performed in 58 study participants from a larger cohort. Levels of circulating endothelial progenitor cells, defined as either late (CD34(+)KDR(+) cells) or early (CD34(+)CD133(+)KDR(+) cells) subsets were measured using polychromatic flow cytometry. We additionally measured production of reactive oxygen species in leukocyte subsets (lymphocytes, monocytes and granulocytes) by flow cytometry using intracellular 2',7'-dichlorofluoroscein. The measurements encompassed both basal levels of reactive oxygen species production and capacity for reactive oxygen species production for each leukocyte subset. We found that the late endothelial progenitor subset was negatively associated with levels of ultrafine particles measured within the participant residences and with reactive oxygen species production capacity in lymphocytes. Additionally, the early endothelial progenitor cell levels were positively associated with a personalised measure of ultrafine particle exposure and negatively associated with both basal and capacity for reactive oxygen species production in lymphocytes and granulocytes, respectively. Our results indicate that exposure to fine and ultrafine particles derived from indoor sources may have adverse effects on human vascular health. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Fluid inclusions and biomarkers in the Upper Mississippi Valley zinc-lead district; implications for the fluid-flow and thermal history of the Illinois Basin

USGS Publications Warehouse

Rowan, E. Lanier; Goldhaber, Martin B.

1996-01-01

The Upper Mississippi Valley zinc-lead district is hosted by Ordovician carbonate rocks at the northern margin of the Illinois Basin. Fluid inclusion temperature measurements on Early Permian sphalerite ore from the district are predominantly between 90?C and I50?C. These temperatures are greater than can be explained by their reconstructed burial depth, which was a maximum of approximately 1 km at the time of mineralization. In contrast to the temperatures of mineral formation derived from fluid inclusions, biomarker maturities in the Upper Mississippi Valley district give an estimate of total thermal exposure integrated over time. Temperatures from fluid inclusions trapped during ore genesis with biomarker maturities were combined to construct an estimate of the district's overall thermal history and, by inference, the late Paleozoic thermal and hydrologic history of the Illinois Basin. Circulation of groundwater through regional aquifers, given sufficient flow rates, can redistribute heat from deep in a sedimentary basin to its shallower margins. Evidence for regional-scale circulation of fluids is provided by paleomagnetic studies, regionally correlated zoned dolomite, fluid inclusions, and thermal maturity of organic matter. Evidence for igneous acti vity contemporaneous with mineralization in the vicinity of the Upper Mississippi Valley district is absent. Regional fluid and heat circulation is the most likely explanation for the elevated fluid inclusion temperatures (relative to maximum estimated burial depth) in the Upper Mississippi Valley district. One plausible driving mechanism and flow path for the ore-forming fluids is groundwater recharge in the late Paleozoic Appalachian-Ouachita mountain belt and northward flow through the Reelfoot rift and the proto- Illinois Basin to the Upper Mississippi Valley district. Warm fluid flowing laterally through Cambrian and Ordovician aquifers would then move vertically upward through the fractures that control sphalerite mineralization in the Upper Mississippi Valley district. Biomarker reactant-product measurements on rock extracts from the Upper Mississippi Valley district define a relatively low level ofthermal maturity for the district, 0.353 for sterane and 0.577 for hopane. Recently published kinetic constants permit a time-temperature relationship to be determined from these biomarker maturities. Numerical calculations were made to simulate fluid heat flow through the fracture-controlled ore zones of the Thompson-Temperly mine and heat transfer to the adjacent rocks where biomarker samples were collected. Calculations that combine the fluid inclusion temperatures and the biomarker constraints on thermal maturity indicate that the time interval during which mineralizing fluids circulated through the Upper Mississippi Valley district is on the order of 200,000 years. Fluid inclusion measurements and thermal maturities from biomarkers in the district reflect the duration of peak temperatures resulting from regional fluid circulation. On the basis of thermal considerations, the timing of fluorite mineralization in southern Illinois, and the northward-decreasing pattern of fluorine enrichment in sediments, we hypothesize that the principal flow direction was northward through the Cambrian and Ordovician aquifers of the Illinois Basin. A basin-scale flow system would result in mass transport (hydrocarbon migration, transport of metals in solution) and energy (heat) transport, which would in turn drive chemical reactions (for example, maturation of organic matter, mineralization, diagenetic reactions) within the Illinois Basin and at its margins.

Simultaneous determination of androgenic and estrogenic endpoints in the threespine stickleback (Gasterosteus aculeatus) using quantitative RT-PCR.

PubMed

Hogan, Natacha S; Wartman, Cheryl A; Finley, Megan A; van der Lee, Jennifer G; van den Heuvel, Michael R

2008-12-11

A method to evaluate the expression of three hormone responsive genes, vitellogenin (estrogens), spiggin (androgens), and an androgen receptor (ARbeta) using real-time PCR in threespine stickleback is presented. Primers were designed from previously characterised spiggin and ARbeta sequences, while a homology cloning strategy was used to isolate a partial gene sequence for stickleback vitellogenin (Vtg). Spiggin mRNA was significantly higher in kidneys of field-caught males compared to females by greater than five orders of magnitude while ARbeta levels were only 1.4-fold higher in males. Female fish had four order of magnitude higher liver Vtg expression than wild-captured males. To determine the sensitivity of these genes to induction by hormones, male and female sticklebacks were exposed to 1, 10 and 100 ng/L of methyltestosterone (MT) or estradiol (E2) in a flow-through exposure system for 7 days. Spiggin induction in females, and Vtg induction in males were both detectable at 10 ng/L of MT and E2, respectively. MT exposure did not induce ARbeta expression in the kidneys of female stickleback. In vitro gonadal steroid hormones production was measured in testes and ovaries of exposed stickleback to compare gene expression endpoints to an endpoint of hormonal reproductive alteration. Reduction in testosterone production in ovaries at all three MT exposure concentrations, and ovarian estradiol synthesis at the 100 ng/L exposure were the only effects observed in the in vitro steroidogenesis for either hormone exposure. Application of these methods to assess both androgenic, estrogenic, and anti-steroidogenic properties of environmental contaminants in a single fish species will be a valuable tool for identifying compounds causing reproductive dysfunction in fishes.

SIMPLIFIED MODELING OF AIR FLOW DYNAMICS IN SSD RADON MITIGATION SYSTEMS FOR RESIDENCES WITH GRAVEL BEDS

EPA Science Inventory

In an attempt to better understand the dynamics of subslab air flow, the report suggests that subslab air flow induced by a central suction point be treated as radial air flow through a porous bed contained between two impermeable disks. (NOTE: Many subslab depressurization syste...

Waveguide detection of right-angle-scattered light in flow cytometry

DOEpatents

Mariella, Jr., Raymond P.

2000-01-01

A transparent flow cell is used as an index-guided optical waveguide. A detector for the flow cell but not the liquid stream detects the Right-Angle-Scattered (RAS) Light exiting from one end of the flow cell. The detector(s) could view the trapped RAS light from the flow cell either directly or through intermediate optical light guides. If the light exits one end of the flow cell, then the other end of the flow cell can be given a high-reflectivity coating to approximately double the amount of light collected. This system is more robust in its alignment than the traditional flow cytometry systems which use imaging optics, such as microscope objectives.

Assessment of velocity fields through open-channel flows with an empiric law.

PubMed

Bardiaux, J B; Vazquez, J; Mosé, R

2008-01-01

Most sewer managers are currently confronted with the evaluation of the water discharges, that flow through their networks or go to the discharge system, i.e. rivers in the majority of cases. In this context, the Urban Hydraulic Systems laboratory of the ENGEES is working on the relation between velocity fields and metrology assessment through a partnership with the Fluid and Solid Mechanics Institute of Strasbourg (IMFS). The responsibility is clearly to transform a velocity profile measurement, given by a Doppler sensor developed by the IMFS team, into a water discharge evaluation. The velocity distribution in a cross section of the flow in a channel has attracted the interests of many researchers over the years, due to its practical applications. In the case of free surface flows in narrow open channels the maximum velocity is below the free surface. This phenomenon, usually called "dip-phenomenon", amongst other things, raises the problem of the area explored in the section of measurements. The work presented here tries to create a simple relation making possible to associate the flow with the velocity distribution. This step allows to insert the sensor position into the flow calculation.

A stock-flow consistent input-output model with applications to energy price shocks, interest rates, and heat emissions

NASA Astrophysics Data System (ADS)

Berg, Matthew; Hartley, Brian; Richters, Oliver

2015-01-01

By synthesizing stock-flow consistent models, input-output models, and aspects of ecological macroeconomics, a method is developed to simultaneously model monetary flows through the financial system, flows of produced goods and services through the real economy, and flows of physical materials through the natural environment. This paper highlights the linkages between the physical environment and the economic system by emphasizing the role of the energy industry. A conceptual model is developed in general form with an arbitrary number of sectors, while emphasizing connections with the agent-based, econophysics, and complexity economics literature. First, we use the model to challenge claims that 0% interest rates are a necessary condition for a stationary economy and conduct a stability analysis within the parameter space of interest rates and consumption parameters of an economy in stock-flow equilibrium. Second, we analyze the role of energy price shocks in contributing to recessions, incorporating several propagation and amplification mechanisms. Third, implied heat emissions from energy conversion and the effect of anthropogenic heat flux on climate change are considered in light of a minimal single-layer atmosphere climate model, although the model is only implicitly, not explicitly, linked to the economic model.

Development of a 0.1 μm linewidth fabrication process for x-ray lithography with a laser plasma source

NASA Astrophysics Data System (ADS)

Bobkowski, Romuald; Fedosejevs, Robert; Broughton, James N.

1999-06-01

A process has been developed for the purpose of fabricating 0.1 micron linewidth interdigital electrode patterns based on proximity x-ray lithography using a laser-plasma source. Such patterns are required in the manufacture of surface acoustic wave devices. The x-ray lithography was carried out using emission form a Cu plasma produced by a 15Hz, 248nm KrF excimer laser. A temporally multiplexed 50ps duration seed pulse was used to extract the KrF laser energy producing a train of several 50ps pulses spaced approximately 2ns apart within each output pulse. Each short pulse within the train gave the high focal spot intensity required to achieve high efficiency emission of keV x-rays. The first stage of the overall process involves the fabrication of x-ray mask patterns on 1 micron thick Si3N4 membranes using 3-beam lithography followed by gold electroplating. The second stage involves x-ray exposure of a chemically amplified resist through the mask patterns to produce interdigital electrode patterns with 0.1 micron linewidth. Helium background gas and thin polycarbonate/aluminum filters are employed to prevent debris particles from the laser-plasma source form reaching the exposed sample. A computer control system fires the laser and monitors the x-ray flux from the laser-plasma source to insure the desired x-ray exposure is achieved at the resist. In order to reduce diffusion effects in the chemically amplified resist during the post exposure bake the temperature had to be reduced from that normally used. Good reproduction of 0.1 micron linewidth patterns into the x-ray resist was obtained once the exposure parameters and post exposure bake were optimized. A compact exposure station using flowing helium at atmospheric pressure has also been developed for the process, alleviating the need for a vacuum chamber. The details of the overall process and the compact exposure station will be presented.

A simple and cost-effective molecular diagnostic system and DNA probes synthesized by light emitting diode photolithography

NASA Astrophysics Data System (ADS)

Oleksandrov, Sergiy; Kwon, Jung Ho; Lee, Ki-chang; Sujin-Ku; Paek, Mun Cheol

2014-09-01

This work introduces a novel chip to be used in the future as a simple and cost-effective method for creating DNA arrays using light emission diode (LED) photolithography. The DNA chip platform contains 24 independent reaction sites, which allows for the testing of a corresponding amount of patients' samples in hospital. An array of commercial UV LEDs and lens systems was combined with a microfluidic flow system to provide patterning of 24 individual reaction sites, each with 64 independent probes. Using the LED array instead of conventional laser exposure systems or micro-mirror systems significantly reduces the cost of equipment. The microfluidic system together with microfluidic flow cells drastically reduces the amount of used reagents, which is important due to the high cost of commercial reagents. The DNA synthesis efficiency was verified by fluorescence labeling and conventional hybridization.

Ground-water flow paths and traveltime to three small embayments within the Peconic Estuary, eastern Suffolk County, New York

USGS Publications Warehouse

Schubert, Christopher E.

1999-01-01

The Peconic Estuary, at the eastern end of Long Island, has been plagued by a recurrent algal bloom that has caused the severe decline of local marine resources. Although the onset, duration, and cessation of the bloom remain unpredictable, ground-water discharge has been shown to affect surface-water quality in the western part of the estuary. Results from a study on the North Fork of Long Island indicate that local hydrogeologic factors cause differences in ground-water age and characteristics of discharge to the estuary. The need for information on the local patterns and rates of ground-water discharge to the Peconic Estuary prompted analysis of ground-water flow paths and traveltime to three small embayments within the estuary.Meetinghouse Creek, near the west end of the North Fork; Sag Harbor Cove, in the central part of the South Fork; and West Neck Bay, on Shelter Island.Ground-water-flow models were developed, and particle-tracking procedures were applied to the results of each model, to define the flow paths and traveltime of ground water to the three embayments. The steady-state flow models represent the two-dimensional ground-water-flow system along a vertical section through the uplands of each embayment and simulate long-term hydrologic conditions. The particle-tracking procedure used model-generated ground-water levels and flow rates to calculate the water-particle pathlines and times-of-travel through each flow system from the point of entry (recharge) to the point of exit at streams, the shore, or subsea-discharge areas.Results for the Meetinghouse Creek study area indicate that about 50 percent of the total recharge that enters the system flows southward to Meetinghouse Creek; half of this amount discharges as base flow to the fresh-water reach of the creek, and half as shoreline underflow to the estuarine reach. About 85 percent of the total discharge to Meetinghouse Creek has flowed entirely within the upper glacial aquifer, and about 15 percent has flowed through the Magothy aquifer. The average age of all ground water discharged to Meetinghouse Creek is about 60 years; the average age of base flow to the freshwater reach of the creek is about 7 years, and the average age of shoreline underflow to the estuarine reach is about 120 years. The results for the Sag Harbor Cove study area indicate that about 30 percent of the total recharge that enters the system flows northward to Sag Harbor Cove; about half of this amount discharges as shoreline underflow, and half as subsea underflow. About 40 percent of the total discharge to Sag Harbor Cove has flowed entirely within the upper glacial aquifer, and about 60 percent has flowed through the Pleistocene marine clay unit, Pleistocene(?) sand unit, or Magothy aquifer. The average age of all ground water discharged to Sag Harbor Cove is about 110 years; the average age of shoreline underflow is about 25 years, and the average age of subsea underflow is about 190 years.Results for the West Neck Bay study area indicate that about 65 percent of the total recharge that enters the system flows westward to West Neck Bay; virtually all of this amount discharges as shoreline underflow, but a negligible percentage discharges as subsea underflow. Virtually all discharge to West Neck Bay has flowed entirely within the upper glacial aquifer, although a minor amount has flowed through the Pleistocene marine clay unit. The average age of shoreline underflow to West Neck Bay is about 15 years, and the average age of subsea underflow is about 1,800 years.Ground water that discharges to streams and the shores represented in the models is mostly relatively young water that has flowed entirely within the shallow zones of the flow systems, whereas ground water that discharges to the subsea-discharge areas is mostly old water that has flowed through the deep zones. Data obtained from these models allows evaluation of each embayment.s vulnerability to contaminants introduced at the water table and can guide the development of source-area-protection strategies for the corresponding watersheds.

Self-Contained Automated Methodology for Optimal Flow Control

NASA Technical Reports Server (NTRS)

Joslin, Ronald D.; Gunzburger, Max D.; Nicolaides, Roy A.; Erlebacherl, Gordon; Hussaini, M. Yousuff

1997-01-01

This paper describes a self-contained, automated methodology for active flow control which couples the time-dependent Navier-Stokes system with an adjoint Navier-Stokes system and optimality conditions from which optimal states, i.e., unsteady flow fields and controls (e.g., actuators), may be determined. The problem of boundary layer instability suppression through wave cancellation is used as the initial validation case to test the methodology. Here, the objective of control is to match the stress vector along a portion of the boundary to a given vector; instability suppression is achieved by choosing the given vector to be that of a steady base flow. Control is effected through the injection or suction of fluid through a single orifice on the boundary. The results demonstrate that instability suppression can be achieved without any a priori knowledge of the disturbance, which is significant because other control techniques have required some knowledge of the flow unsteadiness such as frequencies, instability type, etc. The present methodology has been extended to three dimensions and may potentially be applied to separation control, re-laminarization, and turbulence control applications using one to many sensors and actuators.

Mechanisms of Orthostatic Tolerance Improvement Following Artificial Gravity Exposure Differ Between Men and Women

NASA Technical Reports Server (NTRS)

Evans, J. M.; Stenger, M. B.; Ferguson, C. R.; Ribiero, L. C.; Zhang, Q.; Moore, F. B.; Serrador, J.; Smith, J. D.; Knapp, C. F.

2014-01-01

We recently determined that a short exposure to artificial gravity (AG) improved the orthostatic tolerance limit (OTL) of cardiovascularly deconditioned subjects. We now seek to determine the mechanisms of that improvement in these hypovolemic men and women. Methods. We determined the orthostatic tolerance limit (OTL) of 9 men and 8 women following a 90 min exposure to AG compared to 90 min of head down bed rest (HDBR). In both cases (21 days apart), subjects were made hypovolemic (low salt diet plus 20 mg intravenous furosemide). Orthostatic tolerance was determined from a combination of head up tilt and increasing lower body negative pressure until presyncope. Mean values and correlations with OTL were determined for heart rate, blood pressure, stroke volume, cardiac output and peripheral resistance (Finometer), cerebral artery blood velocity (DWL), partial pressure of carbon dioxide (Novametrics) and body segmental impedance (UFI THRIM) were measured during supine baseline, during OTL to presyncope and during supine recovery Results. Orthostatic tolerance of these hypovolemic subjects was significantly greater on the day of AG exposure than on the HDBR day. Regression of OTL on these variables identified significant relationships on the HDBR day that were not evident on the AG day: resting TPR correlated positively while resting cerebral flow correlated negatively with OTL. On both days, women's resting stroke volume correlated positively with orthostatic tolerance. Higher group mean values of stroke volume and cerebral artery flow and lower values of blood pressure, peripheral vascular and cerebrovascular resistance both at control and during OTL testing were observed on the AG day. Even though regression of OTL on resting stroke volume was significant only in women, presyncopal stroke volume reached the same level on each day of study for both men and women while the OTL test lasted 30% longer in men and 22% longer in women. Cerebral artery flow appeared to follow stroke volume and absolute values of cerebral flow did not correlate with the development of presyncope. Women responded to AG exposure with elevated cerebral flow at resting control and throughout the OTL test, implying a loss of autoregulation in deconditioned (hypovolemic) women following AG exposure. Conclusions. Before countermeasures to space flight cardiovascular deconditioning are established, gender differences in cardiovascular responses to orthostatic stress, in general, and to orthostatic stress following exposure to artificial gravity, in particular, need to be determined. Since, in both men and women, a single, acute bout of AG exposure improved orthostatic tolerance, the feasibility of short exposures to AG during longer spaceflights or prior to entry into a gravity (Earth or Mars) environment, should be explored. Given the known beneficial effects of AG on other organ systems, the present study indicates that the positive effects of AG on cardiac stroke volume make AG a likely candidate for maintaining cardiovascular conditioning.

Capsule injection system for a hydraulic capsule pipelining system

DOEpatents

Liu, Henry

1982-01-01

An injection system for injecting capsules into a hydraulic capsule pipelining system, the pipelining system comprising a pipeline adapted for flow of a carrier liquid therethrough, and capsules adapted to be transported through the pipeline by the carrier liquid flowing through the pipeline. The injection system comprises a reservoir of carrier liquid, the pipeline extending within the reservoir and extending downstream out of the reservoir, and a magazine in the reservoir for holding capsules in a series, one above another, for injection into the pipeline in the reservoir. The magazine has a lower end in communication with the pipeline in the reservoir for delivery of capsules from the magazine into the pipeline.

WATER PROCESS SYSTEM FLOW DIAGRAM FOR MTR, TRA603. SUMMARY OF ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

WATER PROCESS SYSTEM FLOW DIAGRAM FOR MTR, TRA-603. SUMMARY OF COOLANT FLOW FROM WORKING RESERVOIR TO INTERIOR OF REACTOR'S THERMAL SHIELD. NAMES TANK SECTIONS. PIPE AND DRAIN-LINE SIZES. SHOWS DIRECTION OF AIR FLOW THROUGH PEBBLE AND GRAPHITE BLOCK ZONE. NEUTRON CURTAIN AND THERMAL COLUMN DOOR. BLAW-KNOX 3150-92-7, 3/1950. INL INDEX NO. 531-0603-51-098-100036, REV. 6. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Continuation Power Flow with Variable-Step Variable-Order Nonlinear Predictor

NASA Astrophysics Data System (ADS)

Kojima, Takayuki; Mori, Hiroyuki

This paper proposes a new continuation power flow calculation method for drawing a P-V curve in power systems. The continuation power flow calculation successively evaluates power flow solutions through changing a specified value of the power flow calculation. In recent years, power system operators are quite concerned with voltage instability due to the appearance of deregulated and competitive power markets. The continuation power flow calculation plays an important role to understand the load characteristics in a sense of static voltage instability. In this paper, a new continuation power flow with a variable-step variable-order (VSVO) nonlinear predictor is proposed. The proposed method evaluates optimal predicted points confirming with the feature of P-V curves. The proposed method is successfully applied to IEEE 118-bus and IEEE 300-bus systems.

Non-Darcy flow of water through woodchip media

USDA-ARS?s Scientific Manuscript database

A denitrifying bioreactor is a system where a carbon substrate (commonly woodchips) is used to reduce nitrate concentration in water flow. Knowledge of intrinsic permeability of woodchip media in different types of this system is of great importance for design and modeling. For many years, water flo...

3D Sedimentological and geophysical studies of clastic reservoir analogs: Facies architecture, reservoir properties, and flow behavior within delta front facies elements of the Cretaceous Wall Creek Member, Frontier Formation, Wyoming

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

Christopher D. White

2009-12-21

Significant volumes of oil and gas occur in reservoirs formed by ancient river deltas. This has implications for the spatial distribution of rock types and the variation of transport properties. A between mudstones and sandstones may form baffles that influence productivity and recovery efficiency. Diagenetic processes such as compaction, dissolution, and cementation can also alter flow properties. A better understanding of these properties and improved methods will allow improved reservoir development planning and increased recovery of oil and gas from deltaic reservoirs. Surface exposures of ancient deltaic rocks provide a high-resolution view of variability. Insights gleaned from these exposures canmore » be used to model analogous reservoirs, for which data is sparser. The Frontier Formation in central Wyoming provides an opportunity for high-resolution models. The same rocks exposed in the Tisdale anticline are productive in nearby oil fields. Kilometers of exposure are accessible, and bedding-plane exposures allow use of high-resolution ground-penetrating radar. This study combined geologic interpretations, maps, vertical sections, core data, and ground-penetrating radar to construct geostatistical and flow models. Strata-conforming grids were use to reproduce the observed geometries. A new Bayesian method integrates outcrop, core, and radar amplitude and phase data. The proposed method propagates measurement uncertainty and yields an ensemble of plausible models for calcite concretions. These concretions affect flow significantly. Models which integrate more have different flow responses from simpler models, as demonstrated an exhaustive two-dimensional reference image and in three dimensions. This method is simple to implement within widely available geostatistics packages. Significant volumes of oil and gas occur in reservoirs that are inferred to have been formed by ancient river deltas. This geologic setting has implications for the spatial distribution of rock types (\\Eg sandstones and mudstones) and the variation of transport properties (\\Eg permeability and porosity) within bodies of a particular rock type. Both basin-wide processes such as sea-level change and the autocyclicity of deltaic processes commonly cause deltaic reservoirs to have large variability in rock properties; in particular, alternations between mudstones and sandstones may form baffles and trends in rock body permeability can influence productivity and recovery efficiency. In addition, diagenetic processes such as compaction, dissolution, and cementation can alter the spatial pattern of flow properties. A better understanding of these properties, and improved methods to model the properties and their effects, will allow improved reservoir development planning and increased recovery of oil and gas from deltaic reservoirs. Surface exposures of ancient deltaic rocks provide a high resolution, low uncertainty view of subsurface variability. Patterns and insights gleaned from these exposures can be used to model analogous reservoirs, for which data is much sparser. This approach is particularly attractive when reservoir formations are exposed at the surface. The Frontier Formation in central Wyoming provides an opportunity for high resolution characterization. The same rocks exposed in the vicinity of the Tisdale anticline are productive in nearby oil fields, including Salt Creek. Many kilometers of good-quality exposure are accessible, and the common bedding-plane exposures allow use of shallow-penetration, high-resolution electromagnetic methods known as ground-penetrating radar. This study combined geologic interpretations, maps, vertical sections, core data, and ground-penetrating radar to construct high-resolution geostatistical and flow models for the Wall Creek Member of the Frontier Formation. Stratal-conforming grids were use to reproduce the progradational and aggradational geometries observed in outcrop and radar data. A new, Bayesian method integrates outcrop--derived statistics, core observations of concretions, and radar amplitude and phase data. The proposed method consistently propagates measurement uncertainty through the model-building process, and yields an ensemble of plausible models for diagenetic calcite concretions. These concretions have a statistically significant on flow. Furthermore, neither geostatistical data from the outcrops nor geophysical data from radar is sufficient: models which integrate these data have significantly different flow responses. This was demonstrated both for an exhaustive two-dimensional reference image and in three dimensions, using flow simulations. This project wholly supported one PhD student and part of the education of an additional MS and PhD student. It helped to sponsor 6 refereed articles and 8 conference or similar presentations.« less

The effects of vasoactive agents on flow through saphenous vein grafts during lower-extremity peripheral vascular surgery.

PubMed

Maslow, Andrew D; Bert, Arthur; Slaiby, Jeffrey; Carney, William; Marcaccio, Edward

2007-06-01

The purpose of this study was to assess the effects of hemodynamic alterations on vein graft flow during peripheral vascular surgery. It was hypothesized that vasopressors can be administered without compromising flow through the vein grafts. Tertiary care center, university medical center. Randomized placebo-controlled double-blinded study. The effects of phenylephrine, epinephrine, milrinone, intravenous fluid, and placebo on newly constructed peripheral vein grafts were assessed in 60 patients (12 patients in each of 5 groups). Systemic and central hemodynamics were measured by using intra-arterial and pulmonary artery catheters. Vein graft flow was measured by using a transultrasonic flow probe (Transultrasonic Inc, Ithaca, NY). Phenylephrine increased systemic mean blood pressure (mBP) (68.2-94.0 mmHg, p < 0.01), systemic vascular resistance (SVR) (1,091-1,696 dynes x sec x cm(-5), p < 0.001), and vein graft flow (39.5-58.9 mL/min, p < 0.01), whereas cardiac output remained unchanged. Epinephrine resulted in increased cardiac output (4.4-6.9 L/min, p < 0.01) and mBP (72.7-89.1 mmHg, p < 0.01), whereas vein graft flow was reduced in 6 of 12 patients. Intravenous fluid administration resulted in a relatively smaller increase in graft flow (37.6-46.0 mL/min, p < 0.05), an increase in cardiac output, and an insignificant decrease in SVR. Other treatments had either little or no effect on vein graft flow. The study hypothesis was partly supported. Although both phenylephrine and epinephrine increased blood pressure, only the former increased vein graft flow in all patients. In conjunction with increases in graft flow after fluid administration, these data suggest that factors affecting vein graft flow are not just simply related to systemic hemodynamics.

Joint NOAA/NWS/USGS prototype debris flow warning system for recently burned areas in Southern California

USGS Publications Warehouse

Restrepo, P.; Jorgensen, D.P.; Cannon, S.H.; Costa, J.; Laber, J.; Major, J.; Martner, B.; Purpura, J.; Werner, K.

2008-01-01

Debris flows, also known as mudslides, are composed gravity-driven mixtures of sediment and water that travel through steep channels, over open hillslopes, and the like. Addressing this issue, US Geological Survey (USGS) and NOAA have established a debris-flow warning system that has the ability to monitor and forecast precipitation and issue timely weather hazard warning. In 2005, this joint NOAA-USGS prototype debris-flow warning system was issued in Southern California and as a result, it has provided valuable information to emergency managers in affected communities.

A Computer Simulation of Audience Exposure in a Mass Media System: The United Nations Information Campaign in Cincinnati, 1947-1948.

ERIC Educational Resources Information Center

Kramer, John Francis

A simulation of Cincinnati mass media system predicts frequency and reach of flow of messages from known facts taken from census statistics, newspaper and radio audience studies, and a content analysis of the press relevant to attitudes and opinions measured by NORC survey of the effects of a public information campaign on the United Nations made…

Analysis of systems hardware flown on LDEF. Results of the systems special investigation group

NASA Technical Reports Server (NTRS)

Dursch, Harry W.; Spear, W. Steve; Miller, Emmett A.; Bohnhoff-Hlavacek, Gail L.; Edelman, Joel

1992-01-01

The Long Duration Exposure Facility (LDEF) was retrieved after spending 69 months in low Earth orbit (LEO). LDEF carried a remarkable variety of mechanical, electrical, thermal, and optical systems, subsystems, and components. The Systems Special Investigation Group (Systems SIG) was formed to investigate the effects of the long duration exposure to LEO on systems related hardware and to coordinate and collate all systems analysis of LDEF hardware. Discussed here is the status of the LDEF Systems SIG investigation through the end of 1991.

Analysis of systems hardware flown on LDEF. Results of the systems special investigation group

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

Dursch, H.W.; Spear, W.S.; Miller, E.A.

1992-04-01

The Long Duration Exposure Facility (LDEF) was retrieved after spending 69 months in low Earth orbit (LEO). LDEF carried a remarkable variety of mechanical, electrical, thermal, and optical systems, subsystems, and components. The Systems Special Investigation Group (Systems SIG) was formed to investigate the effects of the long duration exposure to LEO on systems related hardware and to coordinate and collate all systems analysis of LDEF hardware. Discussed here is the status of the LDEF Systems SIG investigation through the end of 1991.

Analysis of the Electrohydrodynamic Flow in a Symmetric System of Electrodes by the Method of Dynamic Current-Voltage Characteristics

NASA Astrophysics Data System (ADS)

Stishkov, Yu. K.; Zakir'yanova, R. E.

2018-04-01

We have solved the problem of injection-type through electrohydrodynamic (EHD) flow in a closed channel. We have considered a model of a liquid with four types of ions. It is shown that a through EHD flow without internal vortices in the electrode gap is formed for the ratio 2 : 1 of the initial injection current from the electrodes in the channel. The structure of the flow in different parts of the channel and the integral characteristics of the flow have been analyzed. It is shown that for a quadratic function of injection at the electrodes, the current-voltage characteristic of the flow is also quadratic.

Atomizing, continuous, water monitoring module

DOEpatents

Thompson, C.V.; Wise, M.B.

1997-07-08

A system for continuously analyzing volatile constituents of a liquid is described. The system contains a pump for continuously pumping the liquid to be tested at a predetermined flow rate into an extracting container through a liquid directing tube having an orifice at one end and positioned to direct the liquid into the extracting container at a flow rate sufficient to atomize the liquid within the extracting container. A continuous supply of helium carrier gas at a predetermined flow rate is directed through a tube into the extracting container and co-mingled with the atomized liquid to extract the volatile constituents contained within the atomized liquid. The helium containing the extracted volatile constituents flows out of the extracting container into a mass spectrometer for an analysis of the volatile constituents of the liquid. 3 figs.

Atomizing, continuous, water monitoring module

DOEpatents

Thompson, Cyril V.; Wise, Marcus B.

1997-01-01

A system for continuously analyzing volatile constituents of a liquid is described. The system contains a pump for continuously pumping the liquid to be tested at a predetermined flow rate into an extracting container through a liquid directing tube having an orifice at one end and positioned to direct the liquid into the extracting container at a flow rate sufficient to atomize the liquid within the extracting container. A continuous supply of helium carrier gas at a predetermined flow rate is directed through a tube into the extracting container and co-mingled with the atomized liquid to extract the volatile constituents contained within the atomized liquid. The helium containing the extracted volatile constituents flows out of the extracting container into a mass spectrometer for an analysis of the volatile constituents of the liquid.

Apparatus for moving a pipe inspection probe through piping

DOEpatents

Zollinger, W.T.; Appel, D.K.; Lewis, G.W.

1995-07-18

A method and apparatus are disclosed for controllably moving devices for cleaning or inspection through piping systems, including piping systems with numerous piping bends therein, by using hydrostatic pressure of a working fluid introduced into the piping system. The apparatus comprises a reservoir or other source for supplying the working fluid to the piping system, a launch tube for admitting the device into the launcher and a reversible, positive displacement pump for controlling the direction and flow rate of the working fluid. The device introduced into the piping system moves with the flow of the working fluid through the piping system. The launcher attaches to the valved ends of a piping system so that fluids in the piping system can recirculate in a closed loop. The method comprises attaching the launcher to the piping system, supplying the launcher with working fluid, admitting the device into the launcher, pumping the working fluid in the direction and at the rate desired so that the device moves through the piping system for pipe cleaning or inspection, removing the device from the launcher, and collecting the working fluid contained in the launcher. 8 figs.

Apparatus for moving a pipe inspection probe through piping

DOEpatents

Zollinger, W. Thor; Appel, D. Keith; Lewis, Gregory W.

1995-01-01

A method and apparatus for controllably moving devices for cleaning or inspection through piping systems, including piping systems with numerous piping bends therein, by using hydrostatic pressure of a working fluid introduced into the piping system. The apparatus comprises a reservoir or other source for supplying the working fluid to the piping system, a launch tube for admitting the device into the launcher and a reversible, positive displacement pump for controlling the direction and flow rate of the working fluid. The device introduced into the piping system moves with the flow of the working fluid through the piping system. The launcher attaches to the valved ends of a piping system so that fluids in the piping system can recirculate in a closed loop. The method comprises attaching the launcher to the piping system, supplying the launcher with working fluid, admitting the device into the launcher, pumping the working fluid in the direction and at the rate desired so that the device moves through the piping system for pipe cleaning or inspection, removing the device from the launcher, and collecting the working fluid contained in the launcher.

Health risk represented by inhaling polycyclic aromatic hydrocarbons (PAH) during daily commuting involving using a high traffic flow route in Bogotá.

PubMed

Pachón, Jorge E; Sarmiento, Hugo; Hoshiko, Tomomi

2013-01-01

Assessing the risk to health by inhaling particles and particle-bound PAH during daily commuting along a high traffic flow route/corridor in Bogotá. A van was equipped with a PAS2000 photo-electric sensor for real-time measurement of particle-bound PAH and a Dust Trakfor monitoring PM10 concentration; it drove along typical commuting routes in the city. Exposure to particles and particle-bound PAH was assessed by using an inhalation intake model. A similar trend was observed for both PM10 and PAH concentration, indicating that traffic was the same source for both contaminants. Extreme PM10 and PAH inhalation concentrations were recorded every time direct bus and microbus emissions were measured by the van. Inhalation model results indicated that exposure was significantly greater when using a venues having mixed traffic use (i.e. buses, microbuses, passenger vehicles, motorcycles) compared to using roads where the TransMilenio system (articulated buses) had been implemented. The results may support evaluating bus drivers, commuters and bike users' exposure to toxic compounds in the city.

Methods and systems for fabricating high quality superconducting tapes

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

Majkic, Goran; Selvamanickam, Venkat

An MOCVD system fabricates high quality superconductor tapes with variable thicknesses. The MOCVD system can include a gas flow chamber between two parallel channels in a housing. A substrate tape is heated and then passed through the MOCVD housing such that the gas flow is perpendicular to the tape's surface. Precursors are injected into the gas flow for deposition on the substrate tape. In this way, superconductor tapes can be fabricated with variable thicknesses, uniform precursor deposition, and high critical current densities.

[Development of automatic urine monitoring system].

PubMed

Wei, Liang; Li, Yongqin; Chen, Bihua

2014-03-01

An automatic urine monitoring system is presented to replace manual operation. The system is composed of the flow sensor, MSP430f149 single chip microcomputer, human-computer interaction module, LCD module, clock module and memory module. The signal of urine volume is captured when the urine flows through the flow sensor and then displayed on the LCD after data processing. The experiment results suggest that the design of the monitor provides a high stability, accurate measurement and good real-time, and meets the demand of the clinical application.

Freshwater in situ toxicity testing: Daphnia magna, Ceriodaphnia dubia, Pimephales promelas, Hyalella azteca and Chironomus tentans

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

Burton, G.A. Jr.

The use of traditional laboratory toxicity test species in field exposures have proven to be a valuable assessment tool for monitoring effluent, water, sediment and storm water quality. Mimicking fluctuating exposures of stressors with associated interactions with differing physico-chemical variables is difficult. In situ exposures are conducted for similar time periods measuring similar response endpoints as in more traditional laboratory tests. However, organisms are transferred to the field and exposed in various types of test chambers. The author has observed responses which are similar and which are significantly different from simultaneous laboratory exposures. Temperature, dissolved oxygen, suspended solids, natural light,more » flow, and predation may affect in situ responses, but are often removed from laboratory exposures. The strengths and weaknesses observed with these test systems over the past few years will be reviewed.« less

Spatial distribution of pulmonary blood flow in dogs in increased force environments

NASA Technical Reports Server (NTRS)

Greenleaf, J. F.; Ritman, E. L.; Chevalier, P. A.; Sass, D. J.; Wood, E. H.

1978-01-01

Spatial distribution of pulmonary blood flow during 2- to 3-min exposures to 6-8 Gy acceleration was studied, using radioactive microspheres in dogs, and compared to previously reported 1 Gy control distributions. Isotope distributions were measured by scintiscanning individual 1-cm-thick cross sections of excised, fixed lungs. Results indicate: (1) the fraction of cardiac output traversing left and right lungs did not change systematically with the duration and magnitude of acceleration; but (2) the fraction is strongly affected by the occurrence or absence of fast deep breaths, which cause an increase or decrease, respectively, in blood flow through the dependent lung; and (3) Gy acceleration caused a significant increase in relative pulmonary vascular resistance (PVR) in nondependent and dependent regions of the lung concurrent with a decrease in PVR in the midsagittal region of the thorax.

Historical View on Lead: Guidelines and Regulations.

PubMed

Pohl, Hana R; Ingber, Susan Z; Abadin, Henry G

2017-04-10

Lead has been used in many commodities for centuries. As a result, human exposure has occurred through the production and use of these lead-containing products. For example, leaded gasoline, lead-based paint, and lead solder/pipes in water distribution systems have been important in terms of exposure potential to the general population. Worker exposures occur in various industrial activities such as lead smelting and refining, battery manufacturing, steel welding or cutting operations, printing, and construction. Some industrial locations have also been a source of exposure to the surrounding communities. While the toxicity of relatively high lead exposures has been recognized for centuries, modern scientific studies have shown adverse health effects at very low doses, particularly in the developing nervous system of fetuses and children. This chapter reflects on historical and current views on lead toxicity. It also addresses the development and evolution of exposure prevention policies. As discussed here, these lead policies target a variety of potential exposure routes and sources. The changes reflect our better understanding of lead toxicity. The chapter provides lead-related guidelines and regulations currently valid in the U. S. and in many countries around the world. The reader will learn about the significant progress that has been made through regulations and guidelines to reduce exposure and prevent lead toxicity.

USE OF SEMI-PERMEABLE MEMBRANE DEVICES TO MONITOR POLLUTANTS IN WATER AND ASSESS THEIR EFFECTS: A LABORATORY TEST AND FIELD VERIFICATION. (U915464)

EPA Science Inventory

Uptake of eight pesticides of different classes (organochlorines, synthetic pyrethroids, dinitroanilines, amides) by semi-permeable membrane devices (SPMDs) was studied in a laboratory continuous-flow system. After 20 days of exposure, membrane concentration factors were in th...

Monoterpene oxidation in an oxidative flow reactor: SOA yields and the relationship between bulk gas-phase properties and organic aerosol growth

NASA Astrophysics Data System (ADS)

Friedman, B.; Link, M.; Farmer, D.

2016-12-01

We use an oxidative flow reactor (OFR) to determine the secondary organic aerosol (SOA) yields of five monoterpenes (alpha-pinene, beta-pinene, limonene, sabinene, and terpinolene) at a range of OH exposures. These OH exposures correspond to aging timescales of a few hours to seven days. We further determine how SOA yields of beta-pinene and alpha-pinene vary as a function of seed particle type (organic vs. inorganic) and seed particle mass concentration. We hypothesize that the monoterpene structure largely accounts for the observed variance in SOA yields for the different monoterpenes. We also use high-resolution time-of-flight chemical ionization mass spectrometry to calculate the bulk gas-phase properties (O:C and H:C) of the monoterpene oxidation systems as a function of oxidant concentrations. Bulk gas-phase properties can be compared to the SOA yields to assess the capability of the precursor gas-phase species to inform the SOA yields of each monoterpene oxidation system. We find that the extent of oxygenated precursor gas-phase species corresponds to SOA yield.

Optimization of valve opening process for the suppression of impulse exhaust noise

NASA Astrophysics Data System (ADS)

Li, Jingxiang; Zhao, Shengdun

2017-02-01

Impulse exhaust noise generated by the sudden impact of discharging flow of pneumatic systems has significant temporal characteristics including high sound pressure and rapid sound transient. The impulse noise exposures are more hazardous to hearing than the energy equivalent uniform noise exposures. This paper presents a novel approach to suppress the peak sound pressure as a major indicator of impulsiveness of the impulse exhaust noise by an optimization of the opening process of valve. Relationships between exhaust flow and impulse noise are described by thermodynamics and noise generating mechanism. Then an optimized approach by controlling the valve opening process is derived under a constraint of pre-setting exhaust time. A modified servo-direct-driven valve was designed and assembled in a typical pneumatic system for the verification experiments comparing with an original solenoid valve. Experimental results with groups of initial cylinder pressures and pre-setting exhaust times are shown to verify the effects of the proposed optimization. Some indicators of energy-equivalent and impulsiveness are introduced to discuss the effects of the noise suppressions. Relationship between noise reduction and exhaust time delay is also discussed.

Optimal-mass-transfer-based estimation of glymphatic transport in living brain

PubMed Central

Zhu, Liangjia; Kolesov, Ivan; Nedergaard, Maiken; Benveniste, Helene; Tannenbaum, Allen

2016-01-01

It was recently shown that the brain-wide cerebrospinal fluid (CSF) and interstitial fluid exchange system designated the ‘glymphatic pathway’ plays a key role in removing waste products from the brain, similarly to the lymphatic system in other body organs1,2. It is therefore important to study the flow patterns of glymphatic transport through the live brain in order to better understand its functionality in normal and pathological states. Unlike blood, the CSF does not flow rapidly through a network of dedicated vessels, but rather through para-vascular channels and brain parenchyma in a slower time-domain, and thus conventional fMRI or other blood-flow sensitive MRI sequences do not provide much useful information about the desired flow patterns. We have accordingly analyzed a series of MRI images, taken at different times, of the brain of a live rat, which was injected with a paramagnetic tracer into the CSF via the lumbar intrathecal space of the spine. Our goal is twofold: (a) find glymphatic (tracer) flow directions in the live rodent brain; and (b) provide a model of a (healthy) brain that will allow the prediction of tracer concentrations given initial conditions. We model the liquid flow through the brain by the diffusion equation. We then use the Optimal Mass Transfer (OMT) approach3 to derive the glymphatic flow vector field, and estimate the diffusion tensors by analyzing the (changes in the) flow. Simulations show that the resulting model successfully reproduces the dominant features of the experimental data. PMID:26877579

Habenula and interpeduncular nucleus differentially modulate predator odor-induced innate fear behavior in rats.

PubMed

Vincenz, Daniel; Wernecke, Kerstin E A; Fendt, Markus; Goldschmidt, Jürgen

2017-08-14

Fear is an important behavioral system helping humans and animals to survive potentially dangerous situations. Fear can be innate or learned. Whereas the neural circuits underlying learned fear are already well investigated, the knowledge about the circuits mediating innate fear is still limited. We here used a novel, unbiased approach to image in vivo the spatial patterns of neural activity in odor-induced innate fear behavior in rats. We intravenously injected awake unrestrained rats with a 99m-technetium labeled blood flow tracer (99mTc-HMPAO) during ongoing exposure to fox urine or water as control, and mapped the brain distribution of the trapped tracer using single-photon emission computed tomography (SPECT). Upon fox urine exposure blood flow increased in a number of brain regions previously associated with odor-induced innate fear such as the amygdala, ventromedial hypothalamus and dorsolateral periaqueductal grey, but, unexpectedly, decreased at higher significance levels in the interpeduncular nucleus (IPN). Significant flow changes were found in regions monosynaptically connected to the IPN. Flow decreased in the dorsal tegmentum and entorhinal cortex. Flow increased in the habenula (Hb) and correlated with odor effects on behavioral defensive strategy. Hb lesions reduced avoidance of but increased approach to the fox urine while IPN lesions only reduced avoidance behavior without approach behavior. Our study identifies a new component, the IPN, of the neural circuit mediating odor-induced innate fear behavior in mammals and suggests that the evolutionarily conserved Hb-IPN system, which has recently been implicated in cued fear, also forms an integral part of the innate fear circuitry. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Martian sedimentary deposits

NASA Technical Reports Server (NTRS)

Dehon, Rene

1992-01-01

The objectives are characterization of flow through outflow channels, sedimentation associated with Martian outflow systems, and documentation of Martian lakes. Over the period of the grant much, but not all, of the study centered on the Maja Valles outflow. Maja served as an example in which the effects of multiple channel routing and ponding could be studied. Maja Valles also served as the test case for calculating flow through an outflow system. Applying the lessons learned in Maja Valles and comparisons and contrast required a scrutiny of other channels.

CityWaterBalance: Track Flows of Water Through an Urban System

EPA Science Inventory

CityWaterBalance provides a reproducible workflow for studying an urban water system. The network of urban water flows and storages can be modeled and visualized. Any city may be modeled with preassembled data, but data for US cities can be gathered via web services using this p...

Flow cytometry analysis of hormone receptors on human peripheral blood mononuclear cells to identify stress-induced neuroendocrine effects

NASA Technical Reports Server (NTRS)

Meehan, R. T.

1986-01-01

Understanding the role of circulating peptide hormones in the pathogenesis of space-flight induced disorders would be greatly facilitated by a method which monitors chronic levels of hormones and their effects upon in vivo cell physiology. Single and simultaneous multiparameter flow cytometry analysis was employed to identify subpopulations of mononuclear cells bearing receptors for ACTH, Endorphin, and Somatomedin-C using monoclonal antibodies and monospecific antisera with indirect immunofluorescence. Blood samples were obtained from normal donors and subjects participating in decompression chamber studies (acute stress), medical student academic examination (chronic stress), and a drug study (Dexamethasone). Preliminary results indicate most ACTH and Endorphin receptor positive cells are monocytes and B-cells, exhibit little diurnal variation but the relative percentages of receptor positive cells are influenced by exposure to various stressors and ACTH inhibition. This study demonstrates the capability of flow cytometry analysis to study cell surface hormone receptor regulation which should allow insight into neuroendocrine modulation of the immune and other cellular systems during exposure to stress or microgravity.

Dynamic Microenvironment Induces Phenotypic Plasticity of Esophageal Cancer Cells Under Flow

NASA Astrophysics Data System (ADS)

Calibasi Kocal, Gizem; Güven, Sinan; Foygel, Kira; Goldman, Aaron; Chen, Pu; Sengupta, Shiladitya; Paulmurugan, Ramasamy; Baskin, Yasemin; Demirci, Utkan

2016-12-01

Cancer microenvironment is a remarkably heterogeneous composition of cellular and non-cellular components, regulated by both external and intrinsic physical and chemical stimuli. Physical alterations driven by increased proliferation of neoplastic cells and angiogenesis in the cancer microenvironment result in the exposure of the cancer cells to elevated levels of flow-based shear stress. We developed a dynamic microfluidic cell culture platform utilizing eshopagael cancer cells as model cells to investigate the phenotypic changes of cancer cells upon exposure to fluid shear stress. We report the epithelial to hybrid epithelial/mesenchymal transition as a result of decreasing E-Cadherin and increasing N-Cadherin and vimentin expressions, higher clonogenicity and ALDH positive expression of cancer cells cultured in a dynamic microfluidic chip under laminar flow compared to the static culture condition. We also sought regulation of chemotherapeutics in cancer microenvironment towards phenotypic control of cancer cells. Such in vitro microfluidic system could potentially be used to monitor how the interstitial fluid dynamics affect cancer microenvironment and plasticity on a simple, highly controllable and inexpensive bioengineered platform.

Multiphysics and Thermal Response Models to Improve Accuracy of Local Temperature Estimation in Rat Cortex under Microwave Exposure

PubMed Central

Kodera, Sachiko; Gomez-Tames, Jose; Hirata, Akimasa; Masuda, Hiroshi; Arima, Takuji; Watanabe, Soichi

2017-01-01

The rapid development of wireless technology has led to widespread concerns regarding adverse human health effects caused by exposure to electromagnetic fields. Temperature elevation in biological bodies is an important factor that can adversely affect health. A thermophysiological model is desired to quantify microwave (MW) induced temperature elevations. In this study, parameters related to thermophysiological responses for MW exposures were estimated using an electromagnetic-thermodynamics simulation technique. To the authors’ knowledge, this is the first study in which parameters related to regional cerebral blood flow in a rat model were extracted at a high degree of accuracy through experimental measurements for localized MW exposure at frequencies exceeding 6 GHz. The findings indicate that the improved modeling parameters yield computed results that match well with the measured quantities during and after exposure in rats. It is expected that the computational model will be helpful in estimating the temperature elevation in the rat brain at multiple observation points (that are difficult to measure simultaneously) and in explaining the physiological changes in the local cortex region. PMID:28358345

Augmentation of Muscle Blood Flow by Ultrasound Cavitation Is Mediated by ATP and Purinergic Signaling.

PubMed

Belcik, J Todd; Davidson, Brian P; Xie, Aris; Wu, Melinda D; Yadava, Mrinal; Qi, Yue; Liang, Sherry; Chon, Chae Ryung; Ammi, Azzdine Y; Field, Joshua; Harmann, Leanne; Chilian, William M; Linden, Joel; Lindner, Jonathan R

2017-03-28

Augmentation of tissue blood flow by therapeutic ultrasound is thought to rely on convective shear. Microbubble contrast agents that undergo ultrasound-mediated cavitation markedly amplify these effects. We hypothesized that purinergic signaling is responsible for shear-dependent increases in muscle perfusion during therapeutic cavitation. Unilateral exposure of the proximal hindlimb of mice (with or without ischemia produced by iliac ligation) to therapeutic ultrasound (1.3 MHz, mechanical index 1.3) was performed for 10 minutes after intravenous injection of 2×10 8 lipid microbubbles. Microvascular perfusion was evaluated by low-power contrast ultrasound perfusion imaging. In vivo muscle ATP release and in vitro ATP release from endothelial cells or erythrocytes were assessed by a luciferin-luciferase assay. Purinergic signaling pathways were assessed by studying interventions that (1) accelerated ATP degradation; (2) inhibited P2Y receptors, adenosine receptors, or K ATP channels; or (3) inhibited downstream signaling pathways involving endothelial nitric oxide synthase or prostanoid production (indomethacin). Augmentation in muscle perfusion by ultrasound cavitation was assessed in a proof-of-concept clinical trial in 12 subjects with stable sickle cell disease. Therapeutic ultrasound cavitation increased muscle perfusion by 7-fold in normal mice, reversed tissue ischemia for up to 24 hours in the murine model of peripheral artery disease, and doubled muscle perfusion in patients with sickle cell disease. Augmentation in flow extended well beyond the region of ultrasound exposure. Ultrasound cavitation produced an ≈40-fold focal and sustained increase in ATP, the source of which included both endothelial cells and erythrocytes. Inhibitory studies indicated that ATP was a critical mediator of flow augmentation that acts primarily through either P2Y receptors or adenosine produced by ectonucleotidase activity. Combined indomethacin and inhibition of endothelial nitric oxide synthase abolished the effects of therapeutic ultrasound, indicating downstream signaling through both nitric oxide and prostaglandins. Therapeutic ultrasound using microbubble cavitation to increase muscle perfusion relies on shear-dependent increases in ATP, which can act through a diverse portfolio of purinergic signaling pathways. These events can reverse hindlimb ischemia in mice for >24 hours and increase muscle blood flow in patients with sickle cell disease. URL: http://clinicaltrials.gov. Unique identifier: NCT01566890. © 2017 American Heart Association, Inc.

Effects of nonylphenol and ethinylestradiol on copper redhorse (Moxostoma hubbsi), an endangered species.

PubMed

Maltais, Domynick; Roy, Robert L

2014-10-01

The copper redhorse, Moxostoma hubbsi, is an endangered species endemic to Quebec. The presence of contaminants, in particular endocrine disrupting chemicals (EDCs), in its habitat has been advanced as partly responsible for the reproductive difficulties encountered by the species. In the present study, immature copper redhorse were exposed to the estrogenic surfactant nonylphenol (NP; 1, 10 and 50µg/l) and the synthetic estrogen 17α-ethinylestradiol (EE2; 10ng/l) for 21 days in a flow-through system. The endpoints investigated included general health indicators (hepatosomatic index and hematocrit), thyroid hormones, sex steroids, brain aromatase activity, plasma and mucus vitellogenin (VTG), cytochrome P4501A protein expression and ethoxyresorufin-O-deethylase activity, heat shock protein 70 (HSP70) and muscle acetylcholinesterase. Exposure to 10ng EE2/l significantly increased brain aromatase activity. Exposure to 50µg NP/l resulted in a significant reduction of plasma testosterone concentrations and a significant induction of hepatic HSP70 protein expression. NP at 50µg/l also induced plasma and mucus VTG. The presence of elevated VTG levels in the surface mucus of immature copper redhorse exposed to NP, and its correlation to plasma VTG, supports the use of mucus VTG as a non-invasive biomarker to evaluate copper redhorse exposure to EDCs in the environment and contribute to restoration efforts of the species. The results of the present study indicate that exposure to high environmentally relevant concentrations of NP and EE2 can affect molecular endpoints related to reproduction in the copper redhorse. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

Microfog lubrication for aircraft engine bearings

NASA Technical Reports Server (NTRS)

Rosenlieb, J. W.

1976-01-01

An analysis and system study was performed to provide design information regarding lubricant and coolant flow rates and flow paths for effective utilization of the lubricant and coolant in a once through bearing oil mist (microfog) and coolant air system. Both static and dynamic tests were performed. Static tests were executed to evaluate and calibrate the mist supply system. A total of thirteen dynamic step speed bearing tests were performed using four different lubricants and several different mist and air supply configurations. The most effective configuration consisted of supplying the mist and the major portion of the cooling air axially through the bearing. The results of these tests have shown the feasibility of using a once through oil mist and cooling air system to lubricate and cool a high speed, high temperature aircraft engine mainshaft bearing.

Modeling flows and concentrations of nine engineered nanomaterials in the Danish environment.

PubMed

Gottschalk, Fadri; Lassen, Carsten; Kjoelholt, Jesper; Christensen, Frans; Nowack, Bernd

2015-05-22

Predictions of environmental concentrations of engineered nanomaterials (ENM) are needed for their environmental risk assessment. Because analytical data on ENM-concentrations in the environment are not yet available, exposure modeling represents the only source of information on ENM exposure in the environment. This work provides material flow data and environmental concentrations of nine ENM in Denmark. It represents the first study that distinguishes between photostable TiO₂ (as used in sunscreens) and photocatalytic TiO₂ (as used in self-cleaning surfaces). It also provides first exposure estimates for quantum dots, carbon black and CuCO₃. Other ENM that are covered are ZnO, Ag, CNT and CeO₂. The modeling is based for all ENM on probability distributions of production, use, environmental release and transfer between compartments, always considering the complete life-cycle of products containing the ENM. The magnitude of flows and concentrations of the various ENM depends on the one hand on the production volume but also on the type of products they are used in and the life-cycles of these products and their potential for release. The results reveal that in aquatic systems the highest concentrations are expected for carbon black and photostable TiO₂, followed by CuCO₃ (under the assumption that the use as wood preservative becomes important). In sludge-treated soil highest concentrations are expected for CeO₂ and TiO₂. Transformation during water treatments results in extremely low concentrations of ZnO and Ag in the environment. The results of this study provide valuable environmental exposure information for future risk assessments of these ENM.

Evaluation of a high framerate multi-exposure laser speckle contrast imaging setup

NASA Astrophysics Data System (ADS)

Hultman, Martin; Fredriksson, Ingemar; Strömberg, Tomas; Larsson, Marcus

2018-02-01

We present a first evaluation of a new multi-exposure laser speckle contrast imaging (MELSCI) system for assessing spatial variations in the microcirculatory perfusion. The MELSCI system is based on a 1000 frames per second 1-megapixel camera connected to a field programmable gate arrays (FPGA) capable of producing MELSCI data in realtime. The imaging system is evaluated against a single point laser Doppler flowmetry (LDF) system during occlusionrelease provocations of the arm in five subjects. Perfusion is calculated from MELSCI data using current state-of-the-art inverse models. The analysis displayed a good agreement between measured and modeled data, with an average error below 6%. This strongly indicates that the applied model is capable of accurately describing the MELSCI data and that the acquired data is of high quality. Comparing readings from the occlusion-release provocation showed that the MELSCI perfusion was significantly correlated (R=0.83) to the single point LDF perfusion, clearly outperforming perfusion estimations based on a single exposure time. We conclude that the MELSCI system provides blood flow images of enhanced quality, taking us one step closer to a system that accurately can monitor dynamic changes in skin perfusion over a large area in real-time.

Active noise reduction in aviation helmets during a military jet trainer test flight.

PubMed

Pääkkönen, R; Kuronen, P; Korteoja, M

2001-01-01

Cockpit noise measurements were carried out in a two-seat jet trainer. For the continuous time and frequency analyses a two-channel tape-recording system was constructed of two miniature microphones connected through an amplifier to a digital tape-recorder. The analysed and averaged noise exposure including radio communication was 80-81 dB when the ANC system was on and 84-89 dB when the ANC system was off. For the conventional flight helmet the same noise exposure was 86 dB, and the noise exposure in the cockpit was 104-106 dB. The effect of the ANC system on the averaged noise exposure (L(Aeq8min)) was an improvement of 4-8 dB over the noise attenuation of the same helmets when the ANC system was off. Both ANC systems worked properly during the test flights. No severe ringing or voice circulation was found except during extreme vibration.

Static and kinetic studies of calmodulin and melittin complex.

PubMed

Itakura, M; Iio, T

1992-08-01

Ca2+ binding to calmodulin triggers conformational change of the protein which induces exposure of hydrophobic surfaces. Melittin has been believed to bind to Ca(2+)-bound calmodulin through the exposed hydrophobic surfaces. However, tryptophan fluorescence measurements and gel chromatography experiments with the melittin-calmodulin system revealed that melittin bound to calmodulin at zero salt concentration even in the absence of Ca2+; addition of salt removed melittin from Ca(2+)-free calmodulin. This means not only the hydrophobic interaction but also the electrostatic interaction contributes to the melittin-calmodulin binding. The fluorescence stopped-flow studies of the dissociation reaction of melittin-calmodulin complex revealed that Ca2+ removal from the complex induced a conformational change of calmodulin, resulting in reduction of the hydrophobic interaction between melittin and calmodulin, but the electrostatic interaction kept melittin still bound to calmodulin for a subsecond lag period, after which melittin dissociated from calmodulin. The fluorescence stopped-flow experiments on the dissociation reaction of complex of melittin and tryptic fragment(s) of calmodulin revealed that the lag period of the melittin dissociation reaction was attributable to the interaction between the C-terminal half of calmodulin and the C-terminal region of melittin.

Dilute Acid and Autohydrolysis Pretreatment

NASA Astrophysics Data System (ADS)

Yang, Bin; Wyman, Charles E.

Exposure of cellulosic biomass to temperatures of about 120-210°C can remove most of the hemicellulose and produce cellulose-rich solids from which high glucose yields are possible with cellulase enzymes. Furthermore, the use of dilute sulfuric acid in this pretreatment operation can increase recovery of hemicellulose sugars substantially to about 85-95% of the maximum possible versus only about 65% if no acid is employed. The use of small-diameter tubes makes it possible to employ high solids concentrations similar to those preferred for commercial operations, with rapid heat-up, good temperature control, and accurate closure of material balances. Mixed reactors can be employed to pretreat larger amounts of biomass than possible in such small-diameter tubes, but solids concentrations are limited to about 15% or less to provide uniform temperatures. Pretreatment of large amounts of biomass at high solids concentrations is best carried out using direct steam injection and rapid pressure release, but closure of material balances in such “steam gun” devices is more difficult. Although flow of water alone or containing dilute acid is not practical commercially, such flow-through configurations provide valuable insight into biomass deconstruction kinetics not possible in the batch tubes, mixed reactors, or steam gun systems.

Reserves and trade jointly determine exposure to food supply shocks

NASA Astrophysics Data System (ADS)

Marchand, P.; Carr, J. A.; Dell'Angelo, J.; Fader, M.; Gephart, J.; Kummu, M.; Magliocca, N. R.; Porkka, M.; Puma, M. J.; Ratajczak, Z.; Rulli, M. C.; Seekell, D.; Suweis, S. S.; Tavoni, A.; D'Odorico, P.

2016-12-01

While a growing proportion of global food consumption is obtained through international trade, there is an ongoing debate on whether this increased reliance on trade benefits or hinders food security, and specifically, the ability of global food systems to absorb shocks due to local or regional losses of production. This paper introduces a model that simulates the short-term response to a food supply shock originating in a single country, which is partly absorbed through domestic reserves and consumption, and partly transmitted through the adjustment of trade flows. By applying the model to publicly-available data for the cereals commodity group over a 17-year period, we find that differential outcomes of supply shocks simulated through this time period are driven not only by the intensification of trade, but as importantly by changes in the distribution of reserves. Our analysis also identifies countries where trade dependency may accentuate the risk of food shortages from foreign production shocks; such risk could be reduced by increasing domestic reserves or importing food from a diversity of suppliers that possess their own reserves. This simulation-based model provides a framework to study the short-term, non-linear and out-of-equilibrium response of trade networks to supply shocks, and could be applied to specific scenarios of environmental or economic perturbations.

Reserves and Trade Jointly Determine Exposure to Food Supply Shocks

NASA Technical Reports Server (NTRS)

Marchand, Philippe; Carr, Joel A.; Dell'Angelo, Jampel; Fader, Marianela; Gephart, Jessica A.; Kummu, Matti; Magliocca, Nicholas; Porkka, Miina; Puma, Michael J.; Zak, Ratajczak

2016-01-01

While a growing proportion of global food consumption is obtained through international trade, there is an ongoing debate on whether this increased reliance on trade benefits or hinders food security, and specifically, the ability of global food systems to absorb shocks due to local or regional losses of production. This paper introduces a model that simulates the short-term response to a food supply shock originating in a single country, which is partly absorbed through decreases in domestic reserves and consumption, and partly transmitted through the adjustment of trade flows. By applying the model to publicly-available data for the cereals commodity group over a 17 year period, we find that differential outcomes of supply shocks simulated through this time period are driven not only by the intensification of trade, but as importantly by changes in the distribution of reserves. Our analysis also identifies countries where trade dependency may accentuate the risk of food shortages from foreign production shocks; such risk could be reduced by increasing domestic reserves or importing food from a diversity of suppliers that possess their own reserves. This simulation-based model provides a framework to study the short-term, nonlinear and out-of-equilibrium response of trade networks to supply shocks, and could be applied to specific scenarios of environmental or economic perturbations.

Reserves and trade jointly determine exposure to food supply shocks

NASA Astrophysics Data System (ADS)

Marchand, Philippe; Carr, Joel A.; Dell'Angelo, Jampel; Fader, Marianela; Gephart, Jessica A.; Kummu, Matti; Magliocca, Nicholas R.; Porkka, Miina; Puma, Michael J.; Ratajczak, Zak; Rulli, Maria Cristina; Seekell, David A.; Suweis, Samir; Tavoni, Alessandro; D'Odorico, Paolo

2016-09-01

While a growing proportion of global food consumption is obtained through international trade, there is an ongoing debate on whether this increased reliance on trade benefits or hinders food security, and specifically, the ability of global food systems to absorb shocks due to local or regional losses of production. This paper introduces a model that simulates the short-term response to a food supply shock originating in a single country, which is partly absorbed through decreases in domestic reserves and consumption, and partly transmitted through the adjustment of trade flows. By applying the model to publicly-available data for the cereals commodity group over a 17 year period, we find that differential outcomes of supply shocks simulated through this time period are driven not only by the intensification of trade, but as importantly by changes in the distribution of reserves. Our analysis also identifies countries where trade dependency may accentuate the risk of food shortages from foreign production shocks; such risk could be reduced by increasing domestic reserves or importing food from a diversity of suppliers that possess their own reserves. This simulation-based model provides a framework to study the short-term, nonlinear and out-of-equilibrium response of trade networks to supply shocks, and could be applied to specific scenarios of environmental or economic perturbations.

Operating Room Environment Control. Part A: a Valve Cannister System for Anesthetic Gas Adsorption. Part B: a State-of-the-art Survey of Laminar Flow Operating Rooms. Part C: Three Laminar Flow Experiments

NASA Technical Reports Server (NTRS)

Meyer, J. S.; Kosovich, J.

1973-01-01

An anesthetic gas flow pop-off valve canister is described that is airtight and permits the patient to breath freely. Once its release mechanism is activated, the exhaust gases are collected at a hose adapter and passed through activated coal for adsorption. A survey of laminar air flow clean rooms is presented and the installation of laminar cross flow air systems in operating rooms is recommended. Laminar flow ventilation experiments determine drying period evaporation rates for chicken intestines, sponges, and sections of pig stomach.

Flow-induced 2D protein crystallization: characterization of the coupled interfacial and bulk flows.

PubMed

Young, James E; Posada, David; Lopez, Juan M; Hirsa, Amir H

2015-05-14

Two-dimensional crystallization of the protein streptavidin, crystallizing below a biotinylated lipid film spread on a quiescent air-water interface is a well studied phenomenon. More recently, 2D crystallization induced by a shearing interfacial flow has been observed at film surface pressures significantly lower than those required in a quiescent system. Here, we quantify the interfacial and bulk flow associated with 2D protein crystallization through numerical modeling of the flow along with a Newtonian surface model. Experiments were conducted over a wide range of conditions resulting in a state diagram delineating the flow strength required to induce crystals for various surface pressures. Through measurements of the velocity profile at the air-water interface, we found that even in the cases where crystals are formed, the macroscopic flow at the interface is well described by the Newtonian model. However, the results show that even in the absence of any protein in the system, the viscous response of the biotinylated lipid film is complicated and strongly dependent on the strength of the flow. This observation suggests that the insoluble lipid film plays a key role in flow-induced 2D protein crystallization.

Effect of flow rate and temperature on transmembrane blood pressure drop in an extracorporeal artificial lung.

PubMed

Park, M; Costa, E L V; Maciel, A T; Barbosa, E V S; Hirota, A S; Schettino, G de P; Azevedo, L C P

2014-11-01

Transmembrane pressure drop reflects the resistance of an artificial lung system to blood transit. Decreased resistance (low transmembrane pressure drop) enhances blood flow through the oxygenator, thereby, enhancing gas exchange efficiency. This study is part of a previous one where we observed the behaviour and the modulation of blood pressure drop during the passage of blood through artificial lung membranes. Before and after the induction of multi-organ dysfunction, the animals were instrumented and analysed for venous-venous extracorporeal membrane oxygenation, using a pre-defined sequence of blood flows. Blood flow and revolutions per minute (RPM) of the centrifugal pump varied in a linear fashion. At a blood flow of 5.5 L/min, pre- and post-pump blood pressures reached -120 and 450 mmHg, respectively. Transmembrane pressures showed a significant spread, particularly at blood flows above 2 L/min; over the entire range of blood flow rates, there was a positive association of pressure drop with blood flow (0.005 mmHg/mL/minute of blood flow) and a negative association of pressure drop with temperature (-4.828 mmHg/(°Celsius). These associations were similar when blood flows of below and above 2000 mL/minute were examined. During its passage through the extracorporeal system, blood is exposed to pressure variations from -120 to 450 mmHg. At high blood flows (above 2 L/min), the drop in transmembrane pressure becomes unpredictable and highly variable. Over the entire range of blood flows investigated (0-5500 mL/min), the drop in transmembrane pressure was positively associated with blood flow and negatively associated with body temperature. © The Author(s) 2014.

Thermal effects on bacterial bioaerosols in continuous air flow.

PubMed

Jung, Jae Hee; Lee, Jung Eun; Kim, Sang Soo

2009-08-01

Exposure to bacterial bioaerosols can have adverse effects on health, such as infectious diseases, acute toxic effects, and allergies. The search for ways of preventing and curing the harmful effects of bacterial bioaerosols has created a strong demand for the study and development of an efficient method of controlling bioaerosols. We investigated the thermal effects on bacterial bioaerosols of Escherichia coli and Bacillus subtilis by using a thermal electric heating system in continuous air flow. The bacterial bioaerosols were exposed to a surrounding temperature that ranged from 20 degrees C to 700 degrees C for about 0.3 s. Both E. coli and B. subtilis vegetative cells were rendered more than 99.9% inactive at 160 degrees C and 350 degrees C of wall temperature of the quartz tube, respectively. Although the data on bacterial injury showed that the bacteria tended to sustain greater damage as the surrounding temperature increased, Gram-negative E. coli was highly sensitive to structural injury but Gram-positive B. subtilis was slightly more sensitive to metabolic injury. In addition, the inactivation of E. coli endotoxins was found to range from 9.2% (at 200 degrees C) to 82.0% (at 700 degrees C). However, the particle size distribution and morphology of both bacterial bioaerosols were maintained, despite exposure to a surrounding temperature of 700 degrees C. Our results show that thermal heating in a continuous air flow can be used with short exposure time to control bacterial bioaerosols by rendering the bacteria and endotoxins to a large extent inactive. This result could also be useful for developing more effective thermal treatment strategies for use in air purification or sterilization systems to control bioaerosols.

Control System for Bearingless Motor-generator

NASA Technical Reports Server (NTRS)

Kascak, Peter E. (Inventor); Jansen, Ralph H. (Inventor); Dever, Timothy P. (Inventor)

2008-01-01

A control system for an electromagnetic rotary drive for bearingless motor-generators comprises a winding configuration comprising a plurality of individual pole pairs through which phase current flows, each phase current producing both a lateral force and a torque. A motor-generator comprises a stator, a rotor supported for movement relative to the stator, and a control system. The motor-generator comprises a winding configuration supported by the stator. The winding configuration comprises at least three pole pairs through which phase current flows resulting in three three-phase systems. Each phase system has a first rotor reference frame axis current that produces a levitating force with no average torque and a second rotor reference frame axis current that produces torque.

Control system for bearingless motor-generator

NASA Technical Reports Server (NTRS)

Jansen, Ralph H. (Inventor); Dever, Timothy P. (Inventor); Kascak, Peter E. (Inventor)

2010-01-01

A control system for an electromagnetic rotary drive for bearingless motor-generators comprises a winding configuration comprising a plurality of individual pole pairs through which phase current flows, each phase current producing both a lateral force and a torque. A motor-generator comprises a stator, a rotor supported for movement relative to the stator, and a control system. The motor-generator comprises a winding configuration supported by the stator. The winding configuration comprises at least three pole pairs through which phase current flows resulting in three three-phase systems. Each phase system has a first rotor reference frame axis current that produces a levitating force with no average torque and a second rotor reference frame axis current that produces torque.

The STRONG STAR Multidisciplinary PTSD Research Consortium

DTIC Science & Technology

2013-09-01

prenatal corticosterone exposure mimics the effects of prenatal stress on adult brain stress response systems and fear extinction behavior...stress, prenatal corticosterone reduced TH mRNA, suggesting that prenatal stress produces its effects on TH mRNA through a mechanism dependent on...Exogenous prenatal corticosterone exposure mimics the effects of prenatal stress on adult brain stress response systems and fear extinction behavior

The effects of exercise on blood flow with reference to the human cardiovascular system: a finite element study

NASA Technical Reports Server (NTRS)

Sud, V. K.; Srinivasan, R. S.; Charles, J. B.; Bungo, M. W.

1992-01-01

This paper reports on a theoretical investigation into the effects of vasomotion on blood through the human cardiovascular system. The finite element method has been used to analyse the model. Vasoconstriction and vasodilation may be effected either through the action of the central nervous system or autoregulation. One of the conditions responsible for vasomotion is exercise. The proposed model has been solved and quantitative results of flows and pressures due to changing the conductances of specific networks of arterioles, capillaries and venules comprising the arms, legs, stomach and their combinations have been obtained.

Method of producing monolithic ceramic cross-flow filter

DOEpatents

Larsen, D.A.; Bacchi, D.P.; Connors, T.F.; Collins, E.L. III

1998-02-10

Ceramic filter of various configuration have been used to filter particulates from hot gases exhausted from coal-fired systems. Prior ceramic cross-flow filters have been favored over other types, but those previously have been assemblies of parts somehow fastened together and consequently subject often to distortion or delamination on exposure hot gas in normal use. The present new monolithic, seamless, cross-flow ceramic filters, being of one-piece construction, are not prone to such failure. Further, these new products are made by a novel casting process which involves the key steps of demolding the ceramic filter green body so that none of the fragile inner walls of the filter is cracked or broken. 2 figs.

Method of producing monolithic ceramic cross-flow filter

DOEpatents

Larsen, David A.; Bacchi, David P.; Connors, Timothy F.; Collins, III, Edwin L.

1998-01-01

Ceramic filter of various configuration have been used to filter particulates from hot gases exhausted from coal-fired systems. Prior ceramic cross-flow filters have been favored over other types, but those previously horn have been assemblies of parts somehow fastened together and consequently subject often to distortion or delamination on exposure hot gas in normal use. The present new monolithic, seamless, cross-flow ceramic filters, being of one-piece construction, are not prone to such failure. Further, these new products are made by novel casting process which involves the key steps of demolding the ceramic filter green body so that none of the fragile inner walls of the filter is cracked or broken.

Control of flow through a vapor generator

DOEpatents

Radcliff, Thomas D.

2005-11-08

In a Rankine cycle system wherein a vapor generator receives heat from exhaust gases, provision is made to avoid overheating of the refrigerant during ORC system shut down while at the same time preventing condensation of those gases within the vapor generator when its temperature drops below a threshold temperature by diverting the flow of hot gases to ambient and to thereby draw ambient air through the vapor generator in the process. In one embodiment, a bistable ejector is adjustable between one position, in which the hot gases flow through the vapor generator, to another position wherein the gases are diverted away from the vapor generator. Another embodiment provides for a fixed valve ejector with a bias towards discharging to ambient, but with a fan on the downstream side of said vapor generator for overcoming this bias.

Ecosystem effects of environmental flows: Modelling and experimental floods in a dryland river

USGS Publications Warehouse

Shafroth, P.B.; Wilcox, A.C.; Lytle, D.A.; Hickey, J.T.; Andersen, D.C.; Beauchamp, Vanessa B.; Hautzinger, A.; McMullen, L.E.; Warner, A.

2010-01-01

Successful environmental flow prescriptions require an accurate understanding of the linkages among flow events, geomorphic processes and biotic responses. We describe models and results from experimental flow releases associated with an environmental flow program on the Bill Williams River (BWR), Arizona, in arid to semiarid western U.S.A. Two general approaches for improving knowledge and predictions of ecological responses to environmental flows are: (1) coupling physical system models to ecological responses and (2) clarifying empirical relationships between flow and ecological responses through implementation and monitoring of experimental flow releases. We modelled the BWR physical system using: (1) a reservoir operations model to simulate reservoir releases and reservoir water levels and estimate flow through the river system under a range of scenarios, (2) one- and two-dimensional river hydraulics models to estimate stage-discharge relationships at the whole-river and local scales, respectively, and (3) a groundwater model to estimate surface- and groundwater interactions in a large, alluvial valley on the BWR where surface flow is frequently absent. An example of a coupled, hydrology-ecology model is the Ecosystems Function Model, which we used to link a one-dimensional hydraulic model with riparian tree seedling establishment requirements to produce spatially explicit predictions of seedling recruitment locations in a Geographic Information System. We also quantified the effects of small experimental floods on the differential mortality of native and exotic riparian trees, on beaver dam integrity and distribution, and on the dynamics of differentially flow-adapted benthic macroinvertebrate groups. Results of model applications and experimental flow releases are contributing to adaptive flow management on the BWR and to the development of regional environmental flow standards. General themes that emerged from our work include the importance of response thresholds, which are commonly driven by geomorphic thresholds or mediated by geomorphic processes, and the importance of spatial and temporal variation in the effects of flows on ecosystems, which can result from factors such as longitudinal complexity and ecohydrological feedbacks. ?? Published 2009.

78 FR 33744 - Sedaxane; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-05

.... The following list of North American Industrial Classification System (NAICS) codes is not intended to... the data supporting the petition, EPA has corrected commodity definitions and recommended additional... exposure through drinking water and in residential settings, but does not include occupational exposure...

VASCULAR AND THROMBOGENIC EFFECTS OF PULMONARY EXPOSURE TO LIBBY AMPHIBOLE

EPA Science Inventory

Acute pulmonary injury and chronic disease can impact the systemic vasculature through the release of inflammogenic and vasoactive mediators from the lung into the circulation. Exposure to Libby amphibole (LA) asbestos is associated with increased human cardiovascular mortality a...

Data system for multiplexed water-current meters

NASA Technical Reports Server (NTRS)

Ramsey, C. R.

1977-01-01

Flow rates at 32 flood plain locations are measured simultaneously by single digital logic unit with high noise immunity. Water flowing through pygmy current meters rotates element that closes electrical contact once every resolution, so flow rate is measured by counting number of closures in time interval.

InfuShield: a shielded enclosure for administering therapeutic radioisotope treatments using standard syringe pumps

PubMed Central

Pratt, Brenda E.; Chittenden, Sarah J.; Murray, Iain S.; Causer, Louise; Grey, Matthew J.; Gear, Jonathan I.; Du, Yong; Flux, Glenn D.

2017-01-01

The administration of radionuclide therapies presents significant radiation protection challenges. The aim of this work was to develop a delivery system for intravenous radioisotope therapies to substantially moderate radiation exposures to staff and operators. A novel device (InfuShield) was designed and tested before being used clinically. The device consists of a shielded enclosure which contains the therapeutic activity and, through the hydraulic action of back-to-back syringes, allows the activity to be administered using a syringe pump external to the enclosure. This enables full access to the pump controls while simultaneously reducing dose to the operator. The system is suitable for use with all commercially available syringe pumps and does not require specific consumables, maximising both the flexibility and economy of the system. Dose rate measurements showed that at key stages in an 131I mIBG treatment procedure, InfuShield can reduce dose to operators by several orders of magnitude. Tests using typical syringes and infusion speeds show no significant alteration in administered flow rates (maximum of 1.2%). The InfuShield system provides a simple, safe and low cost method of radioisotope administration. PMID:28187040

Portable Fluorescence Imaging System for Hypersonic Flow Facilities

NASA Technical Reports Server (NTRS)

Wilkes, J. A.; Alderfer, D. W.; Jones, S. B.; Danehy, P. M.

2003-01-01

A portable fluorescence imaging system has been developed for use in NASA Langley s hypersonic wind tunnels. The system has been applied to a small-scale free jet flow. Two-dimensional images were taken of the flow out of a nozzle into a low-pressure test section using the portable planar laser-induced fluorescence system. Images were taken from the center of the jet at various test section pressures, showing the formation of a barrel shock at low pressures, transitioning to a turbulent jet at high pressures. A spanwise scan through the jet at constant pressure reveals the three-dimensional structure of the flow. Future capabilities of the system for making measurements in large-scale hypersonic wind tunnel facilities are discussed.

A Perspective on the Toxicity of Low Concentrations of Petroleum-Derived Polycyclic Aromatic Hydrocarbons to Early Life Stages of Herring and Salmon

PubMed Central

Page, David S.; Chapman, Peter M.; Landrum, Peter F.; Neff, Jerry; Elston, Ralph

2012-01-01

This article presents a critical review of two groups of studies that reported adverse effects to salmon and herring eggs and fry from exposure to 1 μg/L or less of aqueous total polycyclic aromatic hydrocarbons (TPAH), as weathered oil, and a more toxic aqueous extract of “very weathered oil.” Exposure media were prepared by continuously flowing water up through vertical columns containing gravel oiled at different concentrations of Prudhoe Bay crude oil. Uncontrolled variables associated with the use of the oiled gravel columns included time- and treatment-dependent variations in the PAH concentration and composition in the exposure water, unexplored toxicity from other oil constituents/degradation products, potential toxicity from bacterial and fungal activity, oil droplets as a potential contaminant source, inherent differences between control and exposed embryo populations, and water flow rate differences. Based on a review of the evidence from published project reports, peer-reviewed publications, chemistry data in a public database, and unpublished reports and laboratory records, the reviewed studies did not establish consistent dose (concentration) response or causality and thus do not demonstrate that dissolved PAH alone from the weathered oil resulted in the claimed effects on fish embryos at low μg/L TPAH concentrations. Accordingly, these studies should not be relied on for management decision-making, when assessing the risk of very low–level PAH exposures to early life stages of fish. PMID:22754275

Making Sense of Dynamic Systems: How Our Understanding of Stocks and Flows Depends on a Global Perspective

ERIC Educational Resources Information Center

Fischer, Helen; Gonzalez, Cleotilde

2016-01-01

Stocks and flows (SF) are building blocks of dynamic systems: Stocks change through inflows and outflows, such as our bank balance changing with withdrawals and deposits, or atmospheric CO[subscript 2] with absorptions and emissions. However, people make systematic errors when trying to infer the behavior of dynamic systems, termed SF failure,…

TNF-α inhibition using etanercept prevents noise-induced hearing loss by improvement of cochlear blood flow in vivo.

PubMed

Arpornchayanon, Warangkana; Canis, Martin; Ihler, Friedrich; Settevendemie, Claudia; Strieth, Sebastian

2013-08-01

Exposure to loud noise can impair cochlear microcirculation and cause noise-induced hearing loss (NIHL). TNF-α signaling has been shown to be activated in NIHL and to control spiral modiolar artery vasoconstriction that regulates cochlear microcirculation. It was the aim of this experimental study to analyse the effects of the TNF-α inhibitor etanercept on cochlear microcirculation and hearing threshold shift in NIHL in vivo. After assessment of normacusis using ABR, loud noise (106 dB SPL, 30 minutes) was applied on both ears in guinea pigs. Etanercept was administered systemically after loud noise exposure while control animals received a saline solution. In vivo fluorescence microscopy of strial capillaries was performed after surgical exposure of the cochlea for microcirculatory analysis. ABR measurements were derived from the contralateral ear. Guinea pigs (n = 6, per group). Compared to controls, cochlear blood flow in strial capillary segments was significantly increased in etanercept-treated animals. Additionally, hearing threshold was preserved in animals receiving the TNF-α inhibitor in contrast to a significant threshold raising in controls. TNF-α inhibition using etanercept improves cochlear microcirculation and protects hearing levels after loud noise exposure and appears as a promising treatment strategy for human NIHL.

A three-dimensional numerical model of predevelopment conditions in the Death Valley regional ground-water flow system, Nevada and California

USGS Publications Warehouse

D'Agnese, Frank A.; O'Brien, G. M.; Faunt, C.C.; Belcher, W.R.; San Juan, C.

2002-01-01

In the early 1990's, two numerical models of the Death Valley regional ground-water flow system were developed by the U.S. Department of Energy. In general, the two models were based on the same basic hydrogeologic data set. In 1998, the U.S. Department of Energy requested that the U.S. Geological Survey develop and maintain a ground-water flow model of the Death Valley region in support of U.S. Department of Energy programs at the Nevada Test Site. The purpose of developing this 'second-generation' regional model was to enhance the knowledge an understanding of the ground-water flow system as new information and tools are developed. The U.S. Geological Survey also was encouraged by the U.S. Department of Energy to cooperate to the fullest extent with other Federal, State, and local entities in the region to take advantage of the benefits of their knowledge and expertise. The short-term objective of the Death Valley regional ground-water flow system project was to develop a steady-state representation of the predevelopment conditions of the ground-water flow system utilizing the two geologic interpretations used to develop the previous numerical models. The long-term objective of this project was to construct and calibrate a transient model that simulates the ground-water conditions of the study area over the historical record that utilizes a newly interpreted hydrogeologic conceptual model. This report describes the result of the predevelopment steady-state model construction and calibration. The Death Valley regional ground-water flow system is situated within the southern Great Basin, a subprovince of the Basin and Range physiographic province, bounded by latitudes 35 degrees north and 38 degrees 15 minutes north and by longitudes 115 and 118 degrees west. Hydrology in the region is a result of both the arid climatic conditions and the complex geology. Ground-water flow generally can be described as dominated by interbasinal flow and may be conceptualized as having two main components: a series of relatively shallow and localized flow paths that are superimposed on deeper regional flow paths. A significant component of the regional ground-water flow is through a thick Paleozoic carbonate rock sequence. Throughout the flow system, ground water flows through zones of high transmissivity that have resulted from regional faulting and fracturing. The conceptual model of the Death Valley regional ground-water flow system used for this study is adapted from the two previous ground-water modeling studies. The three-dimensional digital hydrogeologic framework model developed for the region also contains elements of both of the hydrogeologic framework models used in the previous investigations. As dictated by project scope, very little reinterpretation and refinement were made where these two framework models disagree; therefore, limitations in the hydrogeologic representation of the flow system exist. Despite limitations, the framework model provides the best representation to date of the hydrogeologic units and structures that control regional ground-water flow and serves as an important information source used to construct and calibrate the predevelopment, steady-state flow model. In addition to the hydrogeologic framework, a complex array of mechanisms accounts for flow into, through, and out of the regional ground-water flow system. Natural discharges from the regional ground-water flow system occur by evapotranspiration, springs, and subsurface outflow. In this study, evapotranspiration rates were adapted from a related investigation that developed maps of evapotranspiration areas and computed rates from micrometeorological data collected within the local area over a multiyear period. In some cases, historical spring flow records were used to derive ground-water discharge rates for isolated regional springs. For this investigation, a process-based, numerical model was developed to estimat

Assessment of Mitigation Systems on Vapor Intrusion ...

EPA Pesticide Factsheets

Vapor intrusion is the migration of subsurface vapors, including radon and volatile organic compounds (VOCs), in soil gas from the subsurface to indoor air. Vapor intrusion happens because there are pressure and concentration differentials between indoor air and soil gas. Indoor environments are often negatively pressurized with respect to outdoor air and soil gas (for example, from exhaust fans or the stack effect), and this pressure difference allows soil gas containing subsurface vapors to flow into indoor air through advection. In addition, concentration differentials cause VOCs and radon to migrate from areas of higher to lower concentrations through diffusion, which is another cause of vapor intrusion. Current practice for evaluating the vapor intrusion pathway involves a multiple line of evidence approach based on direct measurements in groundwater, external soil gas, subslab soil gas, and/or indoor air. No single line of evidence is considered definitive, and direct measurements of vapor intrusion can be costly, especially where significant spatial and temporal variability require repeated measurements at multiple locations to accurately assess the chronic risks of long-term exposure to volatile organic compounds (VOCs) like chloroform, perchloroethylene (PCE), and trichloroethylene (TCE).

Characterization and Testing of Amidoxime-Based Adsorbent Materials to Extract Uranium from Natural Seawater

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

Kuo, Li-Jung; Janke, Christopher J.; Wood, Jordana R.

Extraction of uranium (U) from seawater for use as a nuclear fuel is a significant challenge due to the low concentration of U in seawater (~3.3 ppb) and difficulties to selectively extract U from the background of major and trace elements in seawater. The Pacific Northwest National Laboratory (PNNL)’s Marine Sciences Laboratory (MSL) has been serving as a marine test site for determining performance characteristics (adsorption capacity, adsorption kinetics, and selectivity) of novel amidoxime-based polymeric adsorbents developed at Oak Ridge National Laboratory (ORNL) under natural seawater exposure conditions. This manuscript describes the performance of three formulations (38H, AF1, AI8) ofmore » amidoxime-based polymeric adsorbents produced at ORNL in MSL’s ambient seawater testing facility. The adsorbents were produced in two forms, fibrous material (40-100 mg samples) and braided material (5-10 g samples), and exposed to natural seawater using flow-through columns and recirculating flumes. All three formulations demonstrated high 56 day uranium adsorption capacity (>3 g U/kg adsorbent). The AF1 formulation had the best uranium adsorption performance, with a 56 day capacity of 3.9 g U/ kg adsorbent, a saturation capacity of 5.4 g U/kg adsorbent, and ~25 days half-saturation time. The two exposure methods, flowthrough columns and flumes, were demonstrated to produce similar performance results, providing confidence that the test methods were reliable, that scaling up from 10’s of mg quantities of exposure in flow-through columns to gram quantities in flumes produced similar results, and confirm that the manufacturing process produces a homogeneous adsorbent. Adsorption kinetics appear to be element specific, with half-saturation times ranging from minutes for the major cations in seawater, to 8-10 weeks for V and Fe. Reducing the exposure time provides a potential pathway to improve the adsorption capacity of U by reducing the V/U ratio on the adsorbent.« less

Laboratory Experiments and Modeling for Interpreting Field Studies of Secondary Organic Aerosol Formation Using an Oxidation Flow Reactor

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

Jimenez, Jose-Luis

2016-02-01

This grant was originally funded for deployment of a suite of aerosol instrumentation by our group in collaboration with other research groups and DOE/ARM to the Ganges Valley in India (GVAX) to study aerosols sources and processing. Much of the first year of this grant was focused on preparations for GVAX. That campaign was cancelled due to political reasons and with the consultation with our program manager, the research of this grant was refocused to study the applications of oxidation flow reactors (OFRs) for investigating secondary organic aerosol (SOA) formation and organic aerosol (OA) processing in the field and laboratorymore » through a series of laboratory and modeling studies. We developed a gas-phase photochemical model of an OFR which was used to 1) explore the sensitivities of key output variables (e.g., OH exposure, O 3, HO 2/OH) to controlling factors (e.g., water vapor, external reactivity, UV irradiation), 2) develop simplified OH exposure estimation equations, 3) investigate under what conditions non-OH chemistry may be important, and 4) help guide design of future experiments to avoid conditions with undesired chemistry for a wide range of conditions applicable to the ambient, laboratory, and source studies. Uncertainties in the model were quantified and modeled OH exposure was compared to tracer decay measurements of OH exposure in the lab and field. Laboratory studies using OFRs were conducted to explore aerosol yields and composition from anthropogenic and biogenic VOC as well as crude oil evaporates. Various aspects of the modeling and laboratory results and tools were applied to interpretation of ambient and source measurements using OFR. Additionally, novel measurement methods were used to study gas/particle partitioning. The research conducted was highly successful and details of the key results are summarized in this report through narrative text, figures, and a complete list of publications acknowledging this grant.« less

Direct Visualization of Mucus Production by the Cold-Water Coral Lophelia pertusa with Digital Holographic Microscopy

PubMed Central

Zetsche, Eva-Maria; Baussant, Thierry; Meysman, Filip J. R.; van Oevelen, Dick

2016-01-01

Lophelia pertusa is the dominant reef-building organism of cold-water coral reefs, and is known to produce significant amounts of mucus, which could involve an important metabolic cost. Mucus is involved in particle removal and feeding processes, yet the triggers and dynamics of mucus production are currently still poorly described because the existing tools to study these processes are not appropriate. Using a novel microscopic technique—digital holographic microscopy (DHM)–we studied the mucus release of L. pertusa under various experimental conditions. DHM technology permits μm-scale observations and allows the visualization of transparent mucoid substances in real time without staining. Fragments of L. pertusa were first maintained in flow-through chambers without stressors and imaged with DHM, then exposed to various stressors (suspended particles, particulate food and air exposure) and re-imaged. Under non-stressed conditions no release of mucus was observed, whilst mucus strings and sheaths were produced in response to suspended particles (activated charcoal and drill cuttings sediment) i.e. in a stressed condition. Mucus strings and so-called ‘string balls’ were also observed in response to exposure to particulate food (brine shrimp Artemia salina). Upon air-exposure, mucus production was clearly visible once the fragments were returned to the flow chamber. Distinct optical properties such as optical path length difference (OPD) were measured with DHM in response to the various stimuli suggesting that different mucus types are produced by L. pertusa. Mucus produced to reject particles is similar in refractive index to the surrounding seawater, suggesting that the energy content of this mucus is low. In contrast, mucus produced in response to either food particle addition or air exposure had a higher refractive index, suggesting a higher metabolic investment in the production of these mucoid substances. This paper shows for the first time the potential of DHM technology for the detection, characterization and quantification of mucus production through OPD measurements in L. pertusa. PMID:26840074

78 FR 25523 - Acceptance of Noise Exposure Map Notice for Oakland County International Airport, Pontiac, Michigan

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-01

... Utilization, Table D5, Runway Utilization By Category of Aircraft; Figure D3, INM Flight Tracks, West Flow, Figure D4, INM Flight Tracks, East Flow. The Future NEM is located in Figure D6, Future Noise Exposure... Assumptions for Future Conditions, 2021. The Flight Tracks depicted in Figure D3, INM Flight Tracks, West Flow...

Flow through PCR module of BioBriefcase

NASA Astrophysics Data System (ADS)

Arroyo, E.; Wheeler, E. K.; Shediac, R.; Hindson, B.; Nasarabadi, S.; Vrankovich, G.; Bell, P.; Bailey, C.; Sheppod, T.; Christian, A. T.

2005-11-01

The BioBriefcase is an integrated briefcase-sized aerosol collection and analysis system for autonomous monitoring of the environment, which is currently being jointly developed by Lawrence Livermore and Sandia National Laboratories. This poster presents results from the polymerase chain reaction (PCR) module of the system. The DNA must be purified after exiting the aerosol collector to prevent inhibition of the enzymatic reaction. Traditional solid-phase extraction results in a large loss of sample. In this flow-through system, we perform sample purification, concentration and amplification in one reactor, which minimizes the loss of material. The sample from the aerosol collector is mixed with a denaturation solution prior to flowing through a capillary packed with silica beads. The DNA adheres to the silica beads allowing the environmental contaminants to be flushed to waste while effectively concentrating the DNA on the silica matrix. The adhered DNA is amplified while on the surface of the silica beads, resulting in a lower limit of detection than an equivalent eluted sample. Thus, this system is beneficial since more DNA is available for amplification, less reagents are utilized, and contamination risks are reduced.

Hydrogeologic investigations of the Sierra Vista subwatershed of the Upper San Pedro Basin, Cochise County, southeast Arizona

USGS Publications Warehouse

Pool, Donald R.; Coes, Alissa L.

1999-01-01

The hydrogeologic system in the Sierra Vista subwatershed of the Upper San Pedro Basin in southeastern Arizona was investigated for the purpose of developing a better understanding of stream-aquifer interactions. The San Pedro River is an intermittent stream that supports a narrow corridor of riparian vegetation. Withdrawal of ground water will result in reduced discharge from the basin through reduced base flow and evapotranspiration; however, the rate and location of reduced discharge are uncertain. The investigation resulted in better definition of distributions of silt and clay in the regional aquifer; changes in seasonal precipitation, runoff, and base flow in the San Pedro River; sources of base flow; and regional water-level changes. Regional ground-water flow is separated into deep-confined and shallow-unconfined systems by silt and clay. Precipitation, runoff, and base flow declined at the Charleston streamflow-gaging station from 1936 through 1997 for the months of June through October. Base flow at the Charleston station during 1996 and 1997 was primarily supplied by ground water recharged near the San Pedro River during recent major runoff and by minor contributions from the regional aquifer. The decline in base flow, about 2 cubic feet per second, has several probable causes including declining runoff and recharge near the river during June through October and increased interception of ground-water flow to the river by wells and phreatophytes. Water levels in wells throughout the regional aquifer generally declined at rates of 0.2 to 0.5 feet per year between 1940 and the mid-1980's, which corresponded with a period of below-average winter precipitation. Water levels in wells in the Fort Huachuca and Sierra Vista areas declined at rates that were faster than regional rates of decline through 1998 and caused diversion of ground-water flow that would have discharged along perennial stream reaches.

DNA Damage, Cell Cycle Arrest, and Apoptosis Induction Caused by Lead in Human Leukemia Cells

PubMed Central

Yedjou, Clement G.; Tchounwou, Hervey M.; Tchounwou, Paul B.

2015-01-01

In recent years, the industrial use of lead has been significantly reduced from paints and ceramic products, caulking, and pipe solder. Despite this progress, lead exposure continues to be a significant public health concern. The main goal of this research was to determine the in vitro mechanisms of lead nitrate [Pb(NO3)2] to induce DNA damage, apoptosis, and cell cycle arrest in human leukemia (HL-60) cells. To reach our goal, HL-60 cells were treated with different concentrations of Pb(NO3)2 for 24 h. Live cells and necrotic death cells were measured by the propidium idiode (PI) assay using the cellometer vision. Cell apoptosis was measured by the flow cytometry and DNA laddering. Cell cycle analysis was evaluated by the flow cytometry. The result of the PI demonstrated a significant (p < 0.05) increase of necrotic cell death in Pb(NO3)2-treated cells, indicative of membrane rupture by Pb(NO3)2 compared to the control. Data generated from the comet assay indicated a concentration-dependent increase in DNA damage, showing a significant increase (p < 0.05) in comet tail-length and percentages of DNA cleavage. Data generated from the flow cytometry assessment indicated that Pb(NO3)2 exposure significantly (p < 0.05) increased the proportion of caspase-3 positive cells (apoptotic cells) compared to the control. The flow cytometry assessment also indicated Pb(NO3)2 exposure caused cell cycle arrest at the G0/G1 checkpoint. The result of DNA laddering assay showed presence of DNA smear in the agarose gel with little presence of DNA fragments in the treated cells compared to the control. In summary, Pb(NO3)2 inhibits HL-60 cells proliferation by not only inducing DNA damage and cell cycle arrest at the G0/G1 checkpoint but also triggering the apoptosis through caspase-3 activation and nucleosomal DNA fragmentation accompanied by secondary necrosis. We believe that our study provides a new insight into the mechanisms of Pb(NO3)2 exposure and its associated adverse health effects. PMID:26703663

DNA Damage, Cell Cycle Arrest, and Apoptosis Induction Caused by Lead in Human Leukemia Cells.

PubMed

Yedjou, Clement G; Tchounwou, Hervey M; Tchounwou, Paul B

2015-12-22

In recent years, the industrial use of lead has been significantly reduced from paints and ceramic products, caulking, and pipe solder. Despite this progress, lead exposure continues to be a significant public health concern. The main goal of this research was to determine the in vitro mechanisms of lead nitrate [Pb(NO₃)₂] to induce DNA damage, apoptosis, and cell cycle arrest in human leukemia (HL-60) cells. To reach our goal, HL-60 cells were treated with different concentrations of Pb(NO₃)₂ for 24 h. Live cells and necrotic death cells were measured by the propidium idiode (PI) assay using the cellometer vision. Cell apoptosis was measured by the flow cytometry and DNA laddering. Cell cycle analysis was evaluated by the flow cytometry. The result of the PI demonstrated a significant (p < 0.05) increase of necrotic cell death in Pb(NO₃)₂-treated cells, indicative of membrane rupture by Pb(NO₃)₂ compared to the control. Data generated from the comet assay indicated a concentration-dependent increase in DNA damage, showing a significant increase (p < 0.05) in comet tail-length and percentages of DNA cleavage. Data generated from the flow cytometry assessment indicated that Pb(NO₃)₂ exposure significantly (p < 0.05) increased the proportion of caspase-3 positive cells (apoptotic cells) compared to the control. The flow cytometry assessment also indicated Pb(NO₃)₂ exposure caused cell cycle arrest at the G₀/G₁ checkpoint. The result of DNA laddering assay showed presence of DNA smear in the agarose gel with little presence of DNA fragments in the treated cells compared to the control. In summary, Pb(NO₃)₂ inhibits HL-60 cells proliferation by not only inducing DNA damage and cell cycle arrest at the G₀/G₁ checkpoint but also triggering the apoptosis through caspase-3 activation and nucleosomal DNA fragmentation accompanied by secondary necrosis. We believe that our study provides a new insight into the mechanisms of Pb(NO₃)₂ exposure and its associated adverse health effects.

Cooling system for a nuclear reactor

DOEpatents

Amtmann, Hans H.

1982-01-01

A cooling system for a gas-cooled nuclear reactor is disclosed which includes at least one primary cooling loop adapted to pass coolant gas from the reactor core and an associated steam generator through a duct system having a main circulator therein, and at least one auxiliary cooling loop having communication with the reactor core and adapted to selectively pass coolant gas through an auxiliary heat exchanger and circulator. The main and auxiliary circulators are installed in a common vertical cavity in the reactor vessel, and a common return duct communicates with the reactor core and intersects the common cavity at a junction at which is located a flow diverter valve operative to effect coolant flow through either the primary or auxiliary cooling loops.

Contamination and restoration of groundwater aquifers.

PubMed Central

Piver, W T

1993-01-01

Humans are exposed to chemicals in contaminated groundwaters that are used as sources of drinking water. Chemicals contaminate groundwater resources as a result of waste disposal methods for toxic chemicals, overuse of agricultural chemicals, and leakage of chemicals into the subsurface from buried tanks used to hold fluid chemicals and fuels. In the process, both the solid portions of the subsurface and the groundwaters that flow through these porous structures have become contaminated. Restoring these aquifers and minimizing human exposure to the parent chemicals and their degradation products will require the identification of suitable biomarkers of human exposure; better understandings of how exposure can be related to disease outcome; better understandings of mechanisms of transport of pollutants in the heterogeneous structures of the subsurface; and field testing and evaluation of methods proposed to restore and cleanup contaminated aquifers. In this review, progress in these many different but related activities is presented. PMID:8354172

The Effect of Atrazine on Louisiana Gulf Coast Estuarine Phytoplankton.

PubMed

Starr, Alexis V; Bargu, Sibel; Maiti, Kanchan; DeLaune, Ronald D

2017-02-01

Pesticides may enter water bodies in areas with a high proportion of agricultural land use through surface runoff, groundwater discharge, and erosion and thus negatively impact nontarget aquatic organisms. The herbicide atrazine is used extensively throughout the Midwest and enters the Mississippi River through surface runoff and groundwater discharge. The purpose of this study was to determine the extent of atrazine contamination in Louisiana's estuaries from Mississippi River water under different flow and nutrient regimes (spring and summer) and its effect on the biomass and oxygen production of the local phytoplankton community. The results showed that atrazine was consistently present in these systems at low levels. Microcosm experiments exposed to an atrazine-dilution series under low and high nutrient conditions to determine the phytoplankton stress response showed that high atrazine levels greatly decreased phytoplankton biomass and oxygen production. Phytoplankton exposed to low and moderate atrazine levels under high nutrient conditions were able to recover after an extended acclimation period. Communities grown under high nutrient conditions grew more rapidly and produced greater levels of oxygen than the low nutrient treatment groups, thus indicating that atrazine exposure may induce a greater stress response in phytoplankton communities under low-nutrient conditions. The native community also experienced a shift from more sensitive species, such as chlorophytes, to potentially more resilient species such as diatoms. The phytoplankton response to atrazine exposure at various concentrations can be especially important to greater trophic levels because their growth and abundance can determine the potential productivity of the entire ecosystem.

Transport of environmental tracers through a karst system with a thick unsaturated zone

NASA Astrophysics Data System (ADS)

Geyer, Tobias; Sültenfuss, Jürgen; Eichinger, Florian; Sauter, Martin

2010-05-01

The transport of the environmental tracers tritium (3H), krypton-85 (85Kr) and helium (3He) in a karst system is investigated. Differences between mean tracer ages determined in spring water are explained by slow percolation of water through the thick unsaturated zone reflecting the importance of slow and diffuse unsaturated flow processes in these systems. Mean tracer ages on the Gallusquelle spring (Swabian Alb) were determined with lumped parameter modeling and decrease in the following order: 3H >> 85Kr > 3He. Since 3H is part of the water molecule it enters a karst system via precipitation, i.e. the mean 3H age is a measure of water flow through the whole karst system, including the unsaturated and saturated zone. The mean 85Kr age and 3H/3He age are measures of time since groundwater recharge arrived at the water table. Therefore our results indicate a long travel time of 3H through the unsaturated zone of the karst system. The interpretation is supported by a two-dimensional numerical simulation of flow and transport in a fissured matrix block that contains a thick unsaturated zone (ca. 100 m) and is drained by a conduit. Transport simulation is performed in the sense of backtracking, i.e. the flow field is reversed, and the boundary conditions are adapted accordingly. At any position in the model domain, the time required for a water molecule to reach the outlet is estimated corresponding to the "life expectancy" (Cornaton and Perrochet 2006), i.e. the life expectancy on the outlet is zero. The simulation of life expectancy of water in the matrix block shows (1) the importance of heterogeneities for interpretation of groundwater ages, (2) the location of stagnant zones in areas of low hydraulic permeability and/or low hydraulic gradient and (3) that flow through unsaturated fissured matrix blocks may cause a considerable travel time of water through a karst system. The travel time of water from the recharge area to the discharge point for the shown example is about 15 years with a travel time of water through the unsaturated zone of 10 years (Geyer 2008). This result reflects the variation of estimated ages for different tracers sampled at the Gallusquelle spring. Additionally, we demonstrate that depending on boundary conditions, the unsaturated zone of a karst system may provide a large water storage since the porous matrix can be expected to be close to saturation and the volume fraction of fissures and conduits is small. Literature Cornaton, F., Perrochet, P. (2006): Ground-water age, life expectancy and transit time distributions in advective-dispersive systems: 1. Generalized reservoir theory. - Advances in Water Resources 29 (9): 1267-1291. Geyer, T. (2008): Characterisation of flow and transport in karst aquifers at catchment scale, Ph.D. diss., Georg-August-Universität Göttingen, 103 pp.

Concentric Split Flow Filter

NASA Technical Reports Server (NTRS)

Stapleton, Thomas J. (Inventor)

2015-01-01

A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

Method of treating emissions of a hybrid vehicle with a hydrocarbon absorber and a catalyst bypass system

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

Roos, Bryan Nathaniel; Gonze, Eugene V; Santoso, Halim G

A method of treating emissions from an internal combustion engine of a hybrid vehicle includes directing a flow of air created by the internal combustion engine when the internal combustion engine is spinning but not being fueled through a hydrocarbon absorber to collect hydrocarbons within the flow of air. When the hydrocarbon absorber is full and unable to collect additional hydrocarbons, the flow of air is directed through an electrically heated catalyst to treat the flow of air and remove the hydrocarbons. When the hydrocarbon absorber is not full and able to collect additional hydrocarbons, the flow of air ismore » directed through a bypass path that bypasses the electrically heated catalyst to conserve the thermal energy stored within the electrically heated catalyst.« less

Bioconcentration of endosulfan in different body tissues of estuarine organisms under sublethal exposure

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

Rajendran, N.; Venugopalan, V.K.

1991-01-01

The organochlorine pesticide endosulfan is applied in the agricultural fields as liquid in India. Investigations have revealed the occurrence and distribution of endosulfan in both biotic and abiotic components of Vellar estuary. The results from static bioassay studies revealed that fishes were more susceptible to the organochlorine pesticides than mollusks. Though the available information on the uptake of endosulfan by the estuarine organisms are limited to whole body tissues, no attempt has been made to find out the extent of uptake of pesticides by the different body tissues of the estuarine organisms. Hence the present study was planned to determinemore » the bioconcentration of endosulfan in different tissues of fishes Mugil cephalus, Mystus gulio, oyster Crassostrea madrasensis and clam Katelysia opima based on the measured concentration of endosulfan in the experimental medium of the continuous flow through system for a period of 10 d.« less

Cellular recovery from exposure to sub-optimal concentrations of AB toxins that inhibit protein synthesis.

PubMed

Cherubin, Patrick; Quiñones, Beatriz; Teter, Ken

2018-02-06

Ricin, Shiga toxin, exotoxin A, and diphtheria toxin are AB-type protein toxins that act within the host cytosol and kill the host cell through pathways involving the inhibition of protein synthesis. It is thought that a single molecule of cytosolic toxin is sufficient to kill the host cell. Intoxication is therefore viewed as an irreversible process. Using flow cytometry and a fluorescent reporter system to monitor protein synthesis, we show a single molecule of cytosolic toxin is not sufficient for complete inhibition of protein synthesis or cell death. Furthermore, cells can recover from intoxication: cells with a partial loss of protein synthesis will, upon removal of the toxin, increase the level of protein production and survive the toxin challenge. Thus, in contrast to the prevailing model, ongoing toxin delivery to the cytosol appears to be required for the death of cells exposed to sub-optimal toxin concentrations.

Understanding pesticides in California's Delta

USGS Publications Warehouse

Kuivila, Kathryn; Orlando, James L.

2012-01-01

The Sacramento-San Joaquin River Delta (Delta) is the hub of California’s water system and also an important habitat for imperiled fish and wildlife. Aquatic organisms are exposed to mixtures of pesticides that flow through the maze of Delta water channels from sources including agricultural, landscape, and urban pest-control applications. While we do not know all of the effects pesticides have on the ecosystem, there is evidence that they cause some damage to organisms in the Delta. Decades of USGS research have provided a good understanding of when, where, and how pesticides enter the Delta. However, pesticide use is continually changing. New field studies and methods are needed so that scientists can analyze which pesticides are present in the Delta, and at what concentrations, enabling them to estimate exposure and ultimate effects on organisms. Continuing research will provide resource managers and stakeholders with crucial information to manage the Delta wisely.

Exposure to Synthetic Gray Water Inhibits Amoeba Encystation and Alters Expression of Legionella pneumophila Virulence Genes

PubMed Central

Lu, Jingrang; Ashbolt, Nicholas J.

2014-01-01

Water conservation efforts have focused on gray water (GW) usage, especially for applications that do not require potable water quality. However, there is a need to better understand environmental pathogens and their free-living amoeba (FLA) hosts within GW, given their growth potential in stored gray water. Using synthetic gray water (sGW) we examined three strains of the water-based pathogen Legionella pneumophila and its FLA hosts Acanthamoeba polyphaga, A. castellanii, and Vermamoeba vermiformis. Exposure to sGW for 72 h resulted in significant inhibition (P < 0.0001) of amoebal encystation versus control-treated cells, with the following percentages of cysts in sGW versus controls: A. polyphaga (0.6 versus 6%), A. castellanii (2 versus 62%), and V. vermiformis (1 versus 92%), suggesting sGW induced maintenance of the actively feeding trophozoite form. During sGW exposure, L. pneumophila culturability decreased as early as 5 h (1.3 to 2.9 log10 CFU, P < 0.001) compared to controls (Δ0 to 0.1 log10 CFU) with flow cytometric analysis revealing immediate changes in membrane permeability. Furthermore, reverse transcription-quantitative PCR was performed on total RNA isolated from L. pneumophila cells at 0 to 48 h after sGW incubation, and genes associated with virulence (gacA, lirR, csrA, pla, and sidF), the type IV secretion system (lvrB and lvrE), and metabolism (ccmF and lolA) were all shown to be differentially expressed. These results suggest that conditions within GW may promote interactions between water-based pathogens and FLA hosts, through amoebal encystment inhibition and alteration of bacterial gene expression, thus warranting further exploration into FLA and L. pneumophila behavior in GW systems. PMID:25381242

Exposure to synthetic gray water inhibits amoeba encystation and alters expression of Legionella pneumophila virulence genes.

PubMed

Buse, Helen Y; Lu, Jingrang; Ashbolt, Nicholas J

2015-01-01

Water conservation efforts have focused on gray water (GW) usage, especially for applications that do not require potable water quality. However, there is a need to better understand environmental pathogens and their free-living amoeba (FLA) hosts within GW, given their growth potential in stored gray water. Using synthetic gray water (sGW) we examined three strains of the water-based pathogen Legionella pneumophila and its FLA hosts Acanthamoeba polyphaga, A. castellanii, and Vermamoeba vermiformis. Exposure to sGW for 72 h resulted in significant inhibition (P < 0.0001) of amoebal encystation versus control-treated cells, with the following percentages of cysts in sGW versus controls: A. polyphaga (0.6 versus 6%), A. castellanii (2 versus 62%), and V. vermiformis (1 versus 92%), suggesting sGW induced maintenance of the actively feeding trophozoite form. During sGW exposure, L. pneumophila culturability decreased as early as 5 h (1.3 to 2.9 log10 CFU, P < 0.001) compared to controls (Δ0 to 0.1 log10 CFU) with flow cytometric analysis revealing immediate changes in membrane permeability. Furthermore, reverse transcription-quantitative PCR was performed on total RNA isolated from L. pneumophila cells at 0 to 48 h after sGW incubation, and genes associated with virulence (gacA, lirR, csrA, pla, and sidF), the type IV secretion system (lvrB and lvrE), and metabolism (ccmF and lolA) were all shown to be differentially expressed. These results suggest that conditions within GW may promote interactions between water-based pathogens and FLA hosts, through amoebal encystment inhibition and alteration of bacterial gene expression, thus warranting further exploration into FLA and L. pneumophila behavior in GW systems. Copyright © 2015, American Society for Microbiology. All Rights Reserved.