PENETRATION OF RADIOACTIVE ISOPROPYL METHYLPHOSPHONOFLUORIDATE (SARIN) VAPOR THROUGH SKIN

1960 ◽  
Vol 38 (9) ◽  
pp. 935-944 ◽  
Author(s):  
M. K. McPhail ◽  
P. A. Adie
Keyword(s):  
Exposure Time ◽  
Vapor Concentration ◽  
Constant Concentration ◽  
Time Required

Studies have been made of the penetration of sarin (isopropyl methylphosphonofluoridate) tagged with P32 through the skin of rabbits. Sarin vapor at a constant concentration was passed through a plastic cup attached to the clipped bellies of rabbits. Using different sizes of cups it has been found that the L(ct)50 (concentration × exposure time required to kill 50% of the animals exposed) decreased as the exposure area was increased. From these experiments it was possible to determine how absorption through skin varies with area exposed, vapor concentration, and exposure time and to find the approximate 'ct' necessary to kill a rabbit for any area of skin exposed.

PENETRATION OF RADIOACTIVE ISOPROPYL METHYLPHOSPHONOFLUORIDATE (SARIN) VAPOR THROUGH SKIN

1960 ◽  
Vol 38 (1) ◽  
pp. 935-944
Author(s):  
M. K. McPhail ◽  
P. A. Adie
Keyword(s):  
Exposure Time ◽  
Vapor Concentration ◽  
Constant Concentration ◽  
Time Required

Studies have been made of the penetration of sarin (isopropyl methylphosphonofluoridate) tagged with P32 through the skin of rabbits. Sarin vapor at a constant concentration was passed through a plastic cup attached to the clipped bellies of rabbits. Using different sizes of cups it has been found that the L(ct)50 (concentration × exposure time required to kill 50% of the animals exposed) decreased as the exposure area was increased. From these experiments it was possible to determine how absorption through skin varies with area exposed, vapor concentration, and exposure time and to find the approximate 'ct' necessary to kill a rabbit for any area of skin exposed.

Efficacy of a combined system of copper and silver and free chlorine for inactivation of Naegleria fowleri amoebas in water

1995 ◽  
Vol 31 (5-6) ◽  
pp. 119-122 ◽  
Author(s):  
J. M. Cassells ◽  
M. T. Yahya ◽  
C. P. Gerba ◽  
J. B. Rose
Keyword(s):  
Synergistic Effect ◽  
Exposure Time ◽  
Silver Ions ◽  
Free Chlorine ◽  
Log10 Reduction ◽  
Naegleria Fowleri ◽  
Combined System ◽  
Water Ph ◽  
Nægleria Fowleri ◽  
Time Required

Electrolytically generated copper and silver ions (400:40 and 800:80 μg/l) were evaluated, separately and combined with 1.0 mg/l free chlorine, for their efficacy in reducing the viable numbers of Naegleria fowleri amoebas in water (pH 7.3 and 23-25°C). Inactivation rates (k = log10 reduction/min) and T99 values (exposure time required to achieve a 99% or a 2 log10 reduction) of the disinfectants were determined. Copper and silver alone, at ratio of 400:40 to 800:80 μg/l caused no significant inactivation of N. fowleri even after 72 hours of exposure (k = 0.00017 and 0.00013, respectively). Addition of 1.0 mg/l free chlorine to water which contained 400:40 or 800:80 μg/l copper and silver resulted in enhanced inactivation rates (k = 0.458 and 0.515, respectively) compared to either chlorine alone (k = 0.33) or the metals alone. Water containing 800:80 μg/l copper and silver with 1.0 mg/l chlorine showed a T99 value of 3.9 minutes, while chlorine alone showed a T99 of 6.1 minutes. Enhanced inactivation of N. fowleri by a combined system of free chlorine and copper and silver may be attributed to the different mechanism that each disinfectant utilizes in inactivating the amoebas, and may suggest a synergistic effect.

scholarly journals Survival of Spacecraft-Associated Microorganisms under Simulated Martian UV Irradiation

2005 ◽  
Vol 71 (12) ◽  
pp. 8147-8156 ◽  
Author(s):  
David A. Newcombe ◽  
Andrew C. Schuerger ◽  
James N. Benardini ◽  
Danielle Dickinson ◽  
Roger Tanner ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Exposure Time ◽  
Bacillus Pumilus ◽  
Space Station ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Uv Spectrum ◽  
Rrna Gene Sequencing ◽  
Time Required ◽  
Associated Surfaces

ABSTRACT Spore-forming microbes recovered from spacecraft surfaces and assembly facilities were exposed to simulated Martian UV irradiation. The effects of UVA (315 to 400 nm), UVA+B (280 to 400 nm), and the full UV spectrum (200 to 400 nm) on the survival of microorganisms were studied at UV intensities expected to strike the surfaces of Mars. Microbial species isolated from the surfaces of several spacecraft, including Mars Odyssey, X-2000 (avionics), and the International Space Station, and their assembly facilities were identified using 16S rRNA gene sequencing. Forty-three Bacillus spore lines were screened, and 19 isolates showed resistance to UVC irradiation (200 to 280 nm) after exposure to 1,000 J m−2 of UVC irradiation at 254 nm using a low-pressure mercury lamp. Spores of Bacillus species isolated from spacecraft-associated surfaces were more resistant than a standard dosimetric strain, Bacillus subtilis 168. In addition, the exposure time required for UVA+B irradiation to reduce the viable spore numbers by 90% was 35-fold longer than the exposure time required for the full UV spectrum to do this, confirming that UVC is the primary biocidal bandwidth. Among the Bacillus species tested, spores of a Bacillus pumilus strain showed the greatest resistance to all three UV bandwidths, as well as the total spectrum. The resistance to simulated Mars UV irradiation was strain specific; B. pumilus SAFR-032 exhibited greater resistance than all other strains tested. The isolation of organisms like B. pumilus SAFR-032 and the greater survival of this organism (sixfold) than of the standard dosimetric strains should be considered when the sanitation capabilities of UV irradiation are determined.

Learning Space in Virtual Environments

2011 ◽  
pp. 135-149
Author(s):  
M. Kyritsis ◽  
S. R. Gulliver ◽  
S. Morar
Keyword(s):  
Environmental Factors ◽  
Virtual Environment ◽  
Exposure Time ◽  
Spatial Layout ◽  
Spatial Knowledge ◽  
Learning Space ◽  
Training Time ◽  
Individual User ◽  
Spatial Knowledge Acquisition ◽  
Time Required

Learning the spatial layout of an environment is essential in application domains including military and emergency personnel training. Traditionally, whilst learning space from a Virtual Environment (VE), identical training time was used for all users - a one size fits all approach to exposure / training time. This chapter, however, identifies both environmental and individual user differences that influence the training time required to ensure effective virtual environment spatial knowledge acquisition (SKA). We introduce the problem of contradicting literature in the area of SKA, and discuss how the amount of exposure time given to a person during VE training is responsible for the feasibility of SKA. We then show how certain individual user differences, as well as environmental factors, impact on the required exposure time that a particular person needs within a specific VE. Individual factors discussed include: the importance of knowledge and experience; the importance of gender; the importance of aptitude and spatial orientation skills; and the importance of cognitive styles. Environmental factors discussed include: Size, Spatial layout complexity and landmark distribution. Since people are different, a one-size fits all approach to training time does not seem logical. The impact of this research domain is important to VE training in general, however within service and military domains ensuring appropriate spatial training is critical in order to ensure that disorientation does not occur in a life / death scenario.

Calculated Interaction of Sprays With Large-Scale Buoyant Flows

1984 ◽  
Vol 106 (2) ◽  
pp. 310-317 ◽  
Author(s):  
R. L. Alpert
Keyword(s):  
Large Scale ◽  
Fire Suppression ◽  
Computer Time ◽  
Vapor Concentration ◽  
Numerical Techniques ◽  
Buoyant Jet ◽  
Numerical Predictions ◽  
Vapor Cloud ◽  
Lift Off ◽  
Time Required

Turbulent, recirculating gas flows resulting from interactions of water droplet sprays with large-scale buoyancy sources are difficult to predict without the use of numerical techniques, especially when spray-induced gas motion is considered. One such flow occurs when a negatively buoyant methane cloud, generated during LNG spills in a wind, is dispersed by a line water spray. Numerical predictions of the ratio of average methane vapor concentration downwind of the line spray to the upwind value correlate as a function of the ratio of methane momentum in the vapor cloud to water momentum in the spray. Warming of the cloud, which occurs when small drops in the spray freeze, leads to the production of positive cloud buoyancy and the possibility of cloud lift off from the ground. Numerical calculations have also been used to predict how a near-ceiling, downward-directed spray interacts with an opposed, buoyant jet issuing from floor level. Recirculating gas motion induced by droplet trajectories is again an important part of the problem. This opposed spray-plume arrangement, which is important in the process of fire suppression by automatic sprinklers, allows the effectiveness of spray cooling of the near-ceiling environment to be determined as a function of droplet injection characteristics. Because of the excessive amounts of computer time required for the solution of both turbulent, buoyant flow problems, it is concluded that much more efficient numerical techniques are needed.

Effect of Dry Heat, Direct Flame, and Straw Burning on Seed Germination of Weed Species Found in Lowbush Blueberry Fields

2016 ◽  
Vol 30 (1) ◽  
pp. 263-270 ◽  
Author(s):  
Scott N. White ◽  
Nathan S. Boyd
Keyword(s):  
Seed Germination ◽  
Exposure Time ◽  
Heat Exposure ◽  
Seed Viability ◽  
Weed Species ◽  
Dry Heat ◽  
Lowbush Blueberry ◽  
Weed Seeds ◽  
Straw Burning ◽  
Time Required

Experiments were conducted to determine the effects of dry heat, direct flame, and straw burning on germination of several weed species from lowbush blueberry fields. Dry heat experiments were designed as factorial arrangements of temperature (100, 200, and 300 C in experiment 1 and room temperature, 100, 200, and 300 C in experiment 2) and exposure time (0, 5, 10, 20, 40, and 80 s in experiment 1 and 2, 5, 10, and 20 s in experiment 2) to determine the exposure time required to reduce germination for each temperature. Susceptibility to dry heat varied across species tested, but germination of spreading dogbane, meadow salsify, fireweed, and hair fescue seeds collected from lowbush blueberry fields in Nova Scotia, Canada generally declined exponentially as a function of duration of heat exposure at the temperatures tested. Germination decreased more rapidly at higher temperatures in all species, although the duration of heat exposure required to reduce germination by 50 and 90% varied across temperatures and species. Exposure of seeds to direct flame rapidly reduced germination, with less than 1 s of exposure required to reduce seed germination of witchgrass, spreading dogbane, and meadow salsify by > 90%. Straw burning did not consistently reduce germination of hair fescue or winter bentgrass, indicating that a surface burn occurring above weed seeds may not be consistently effective at reducing seed viability. These results provide important estimates of the temperature and exposure times required to reduce viability of weed seeds in lowbush blueberry fields and suggest that thermal technologies that expose weed seeds to direct flame will be the most consistent in reducing seed viability.

scholarly journals Comparison Between Single-Aperture and Multi-Aperture Approaches to Computer Correction of Images

2020 ◽  
Vol 237 ◽  
pp. 06003
Author(s):  
Vadim Dudorov ◽  
Anna Eremina
Keyword(s):  
Numerical Simulation ◽  
Exposure Time ◽  
Image Synthesis ◽  
Short Exposure ◽  
Small Scale ◽  
Short Exposure Time ◽  
Observation Systems ◽  
Order Of Magnitude ◽  
Single Aperture ◽  
Time Required

The effectiveness of the reconstruction of images formed by single- and multi-aperture systems and distorted by an atmospheric turbulence is analyzed in this work. Based on numerical simulation, we show that the use of multi-aperture observation systems for the computer correction of atmospheric distortions under anisoplanar conditions can significantly reduce the exposure time. Main distortions are well corrected during image synthesis for a short exposure time, which corresponds to a “frozen” turbulence. The time required for the correction of residual small-scale distortions is an order of magnitude shorter than in the case of synthesis of long-exposure images with the use of traditional single-aperture observation systems.

Learning Space in Virtual Environments

2011 ◽  
pp. 216-230
Author(s):  
M. Kyritsis ◽  
S. R. Gulliver ◽  
S. Morar
Keyword(s):  
Environmental Factors ◽  
Virtual Environment ◽  
Exposure Time ◽  
Spatial Layout ◽  
Spatial Knowledge ◽  
Learning Space ◽  
Training Time ◽  
Individual User ◽  
Spatial Knowledge Acquisition ◽  
Time Required

Learning the spatial layout of an environment is essential in application domains including military and emergency personnel training. Traditionally, whilst learning space from a Virtual Environment (VE), identical training time was used for all users - a one size fits all approach to exposure / training time. This chapter, however, identifies both environmental and individual user differences that influence the training time required to ensure effective virtual environment spatial knowledge acquisition (SKA). We introduce the problem of contradicting literature in the area of SKA, and discuss how the amount of exposure time given to a person during VE training is responsible for the feasibility of SKA. We then show how certain individual user differences, as well as environmental factors, impact on the required exposure time that a particular person needs within a specific VE. Individual factors discussed include: the importance of knowledge and experience; the importance of gender; the importance of aptitude and spatial orientation skills; and the importance of cognitive styles. Environmental factors discussed include: Size, Spatial layout complexity and landmark distribution. Since people are different, a one-size fits all approach to training time does not seem logical. The impact of this research domain is important to VE training in general, however within service and military domains ensuring appropriate spatial training is critical in order to ensure that disorientation does not occur in a life / death scenario.

scholarly journals Tetrabenazine in treatment of hyperkinetic movement disorders: an observational study

2016 ◽  
Vol 10 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Rita Miguel ◽  
Marcelo D. Mendonça ◽  
Raquel Barbosa ◽  
Filipa Ladeira ◽  
Tânia Lampreia ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Exposure Time ◽  
Movement Disorders ◽  
Tic Disorders ◽  
The Other ◽  
Tolerability Profile ◽  
Discontinuation Rate ◽  
Meaningful Improvement ◽  
Minimal Dose ◽  
Time Required

Background: Tetrabenazine (TBZ) is commonly used in hyperkinetic movement disorders. In this retrospective study, we aimed to assess the TBZ effectiveness and adverse events (AEs) in Huntington disease (HD), vascular chorea, tics, dystonia, tardive oromandibular (OM) dyskinesia and other tardive syndromes (TS). Methods: Qualitative analysis of clinical response was used to estimate TBZ effectiveness. TBZ-associated AE frequency and subsequent discontinuation rate were used to estimate tolerability; the tolerability profile was measured through the TBZ minimal dose and exposure time required to elicit AEs. Results: Of 108 included patients, 87% had a clinically meaningful improvement sustained over a period of 40 months. TBZ-responder rate ranged from 100% in HD to 62.5% and 77.1% in tic disorders and OM dyskinesia, respectively ( p < 0.001). TBZ-associated AE frequency ranged from 40.9% in other TS and 41.7% in vascular chorea and HD, to 60% in OM dyskinesia ( p < 0.001). The most common AEs were Parkinsonism (51.8%) and psychiatric disorders (25%). The ‘other AEs’ category (mainly somnolence) presented the shortest minimal exposure time (3 months). AE-eliciting dose differed from 18.8 mg and 25 mg in tics and tardive disorders, to 75 mg in HD ( p = 0.003). Patients with AEs were tendentiously older at TBZ initiation ( p = 0.022). Conclusions: TBZ proved an effective and relatively well tolerated treatment in hyperkinetic disorders, with excellent results in HD. AEs were more common in OM dyskinesia, which may be related to higher age at TBZ initiation. TBZ-associated somnolence and Parkinsonism were more frequent during the titration and maintenance periods, respectively.

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