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3-med-tech:uv-mask:uv-disinfect 2009/07/13 20:17 3-med-tech:uv-mask:uv-disinfect 2010/01/20 07:19 current
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====== Protection from Influenza virus ====== ====== Protection from Influenza virus ======
Martin Meyer Weiss, MD, Peter D. Weiss, MD, Danielle E. Weiss, MD, and Joseph B. Weiss, MD\\ Martin Meyer Weiss, MD, Peter D. Weiss, MD, Danielle E. Weiss, MD, and Joseph B. Weiss, MD\\
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===== UV LIGHT ===== ===== UV LIGHT =====
-Wells, working with Escherichia coli, discovered that UV light can sterilize infectious aerosols.24 UV light is electromagnetic radiation with a wavelength shorter than that of visible light. UV light is categorized as consisting of 3 wavelength bands, each of which has different properties. Ninety-nine percent of the UV light that reaches the earth’s surface is UV-A (400–320 nm). UV-B (320–290 nm) is responsible for skin tanning and sunburn and with long exposure may cause skin malignancies and cataracts.24 UV-C (290–100 nm) has the highest energy of the UV light bands.24 The primary germicidal range for UV light is 260 to 254 nm, which is within the UV-C band. The theory behind use of UV light to disinfect air is that respiratory infections may be spread by suspended aerosols.+  UV light can sterilize infectious aerosols.(24)
 +Wells, working with Escherichia coli, discovered that UV light can sterilize infectious aerosols.24 UV light is electromagnetic radiation with a wavelength shorter than that of visible light. UV light is categorized as consisting of 3 wavelength bands, each of which has different properties.
-Unlike the outdoor atmosphere, where aerosols are rapidly diluted, aerosols may remain suspended and, in relative high concentration, trapped within the air of enclosed buildings for long periods of time. To apply UV irradiation in rooms, UV fixtures have been suspended from walls or ceilings and directed horizontally to irradiate only the air above head level, that is, above 6.5 ft. Such fixtures do not expose occupants to UV light. The upper and lower air mixes because of convection currents related to temperature gradients. Even without fans, there is a complete air exchange between the upper and lower air within rooms at a rate of 95 times per hour.25 The germicidal effect of UV light, however, diminishes at humidities greater than 70% and is low at humidities greater than 80%.27 Technical aspects have been described elsewhere.27,28+  UV light ที่ส่งมาถึงโลก เป็น UV-A ถึง 99% 
 +Ninety-nine percent of the UV light that reaches the earth’s surface is UV-A (400–320 nm). UV-B (320–290 nm) is responsible for **skin tanning and sunburn** and with long exposure may cause **skin malignancies and cataracts**.(24)
 +  UV-C มี highest energy of the UV light
 +UV-C (290–100 nm) has the highest energy of the UV light bands.24 The primary germicidal range for UV light is 260 to 254 nm, which is within the UV-C band. The theory behind use of UV light to disinfect air is that respiratory infections may be spread by suspended aerosols.
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 +  ..Aerosols may remain suspended/concentration/trapped... 
 +Unlike the outdoor atmosphere, where aerosols are rapidly diluted, aerosols may remain suspended and, in relative high concentration, trapped within the air **of enclosed buildings for long periods of time.** To apply UV irradiation in rooms, UV fixtures have been suspended from walls or ceilings and directed horizontally to irradiate only the air above head level, that is, above 6.5 ft. Such fixtures do not expose occupants to UV light. The upper and lower air mixes because of convection currents related to temperature gradients. Even without fans, there is a complete air exchange between the upper and lower air within rooms at a rate of 95 times per hour.25 The germicidal effect of UV light, however, diminishes at humidities greater than 70% and is low at humidities greater than 80%.27 Technical aspects have been described elsewhere.27,28
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 +  .studies in 1940s/use of UV light prevent airborne resp infect, \\
Several studies were undertaken in the 1940s to test the use of UV light in preventing airborne respiratory infections, with 1 positive study and 3 negative studies. The positive study involved a measles outbreak at a rural school system.29 The negative studies involved schools and communities where there was much intermingling outside the UV irradiated area and where the majority of the day was spent without exposure to a UV-C–treated environment.30–32 Several studies were undertaken in the 1940s to test the use of UV light in preventing airborne respiratory infections, with 1 positive study and 3 negative studies. The positive study involved a measles outbreak at a rural school system.29 The negative studies involved schools and communities where there was much intermingling outside the UV irradiated area and where the majority of the day was spent without exposure to a UV-C–treated environment.30–32
 +  UV irradiation..in..hospital and nursing home patients.
-Supporters of UV irradiation argue that UV can be expected to work only at the site where it is applied, and thus, is practical only for those who will be largely confined to a single site, such as hospital and nursing home patients.24 There is some evidence to support this position. McClean, in 1957, installed UV lights in the main building of the Livermore (Calif) Veterans Affairs Hospital.33 Of 209 patients in that building, the incidence of influenza was 2%. In comparison, in 396 patients living in neighboring, unirradiated control buildings, the incidence was 19%.+Supporters of UV irradiation argue that UV can be expected to work only at the site where it is applied, and thus, is practical only for those who will be largely confined to a single site, such as hospital and nursing home patients.24 
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 +  1957,UV lights in..Hospital. incidence 2%. vs 19%
-Although the practical clinical use of UV light as a means for disinfecting the air of respiratory viruses and bacteria is uncertain, the virucidal and bactericidal action, per se, is not in dispute. In vitro studies clearly demonstrate UV light to inactivate 99.99% of influenza virus aerosols.34 UV irradiation is used commercially in wastewater and drinking water treatment35 and is used to pasteurize fruit juices. Mercury vapor lamps emitting UV-C are routinely used to sterilize work areas and equipment in medical facilities and laboratories. UV-C has been found to be effective in sterilizing blood products.36 The application of UV light as a bioterrorism defense has been raised elsewhere.37+There is some evidence to support this position. McClean, in 1957, installed UV lights in the main building of the Livermore (Calif) Veterans Affairs Hospital.33 Of 209 patients in that building, the incidence of influenza was 2%. In comparison, in 396 patients living in neighboring, unirradiated control buildings, the incidence was 19%. 
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 +  In vitro UV light inactivate 99.99% influenza virus aerosols.
-The energy required for germicidal action, as well as adverse effects, is a product of radiation intensity and time. A few seconds of high-intensity radiation, or several hours of low-intensity radiation, may produce the same net amount of radiation and germicidal action.38 Flooding a room above a height of 6.5 ft with high-intensity UV radiation has been found to keep skin and eye exposure well within the safety range.39+Although the practical clinical use of UV light as a means for disinfecting the air of respiratory viruses and bacteria is uncertain, the virucidal and bactericidal action, per se, is not in dispute. In vitro studies clearly demonstrate UV light to inactivate 99.99% of influenza virus aerosols.34  
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 +  UV used in wastewater/drinking water/pasteur fruit juices
-At germicidal UV wavelengths, adjacent thymine bases dimerize, rendering viral or bacterial DNA and RNA incapable of replication.40 Germicidal lamps typically emit UV-C at 16 000 μW s/cm2.41 Solar UV-C is held to be completely absorbed by the atmosphere’s ozone and does not reach the earth’s surface.42,43 Recent evidence, however, demonstrates that UV-C does, in fact, penetrate through the atmosphere to sea level, at an intensity of .004 μW s/cm2 (2.4 × 10_7 J/cm2 over 60 s).44+UV irradiation is used commercially in wastewater and drinking water treatment35 and is used to pasteurize fruit juices.  
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 +  sterilize: work areas/equipment/bloodProducts/bioterrorism defense
 +Mercury vapor lamps emitting UV-C are routinely used to sterilize work areas and equipment in medical facilities and laboratories. UV-C has been found to be effective in sterilizing blood products.36 The application of UV light as a bioterrorism defense has been raised elsewhere.37
-It has long been a puzzle why, in temperate climates, influenza occurs in epidemics only in the winter months,45 why epidemics cease before all those susceptible have been infected, and why influenza outbreaks have occurred simultaneously in geographic sites great distances from each other, where direct contact between those sites was not possible.3 The mystery has been such that 1 reputable journal has published a theory arguing for viruses from space, via cosmic dust, as being responsible for influenza epidemics.46 
 +The energy required for germicidal action, as well as adverse effects, is a product of radiation intensity and time. A few seconds of high-intensity radiation, or several hours of low-intensity radiation, may produce the same net amount of radiation and germicidal action.38 Flooding a room above a height of 6.5 ft with high-intensity UV radiation has been found to keep skin and eye exposure well within the safety range.39
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-The very minute amount of UV-C reaching the ground is likely insufficient to have a deleterious action on viral DNA and probably does not account for the seasonal occurrence of epidemics in the temperate climates. UV-B also has antiviral activity—much weaker than UV-C—but makes up 1% of the light spectrum that penetrates the earth’s atmosphere. As such, it is exponentially more abundant than UV-C at ground level, by 6 orders of magnitude. A decrease in UV-B levels (from air pollution) has been theorized to be a factor in the avian influenza epidemic.47+  viral or bacterial DNA and RNA incapable of replication. 
 + 
 +At germicidal UV wavelengths, adjacent thymine bases dimerize, rendering viral or bacterial DNA and RNA incapable of replication.40  
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 +\\ 
 +  Germicidal lamps emit UV-C at 16 000 μW s/cm2.  
 + 
 +Germicidal lamps typically emit UV-C at 16 000 μW s/cm2.41 Solar UV-C is held to be completely absorbed by the atmosphere’s ozone and does not reach the earth’s surface.42,43  
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 +\\ 
 +  UV-C penetrate to sea level, intensity .004 μW s/cm2 (2.4 × 10_7 J/cm2 over 60 s) 
 +Recent evidence, however, demonstrates that UV-C does, in fact, penetrate through the atmosphere to sea level, at an intensity of .004 μW s/cm2 (2.4 × 10_7 J/cm2 over 60 s).44 
 + 
 + 
 +It has long been a puzzle why, in temperate climates, influenza occurs in epidemics only in the winter months,45 why epidemics cease before all those susceptible have been infected, and why influenza outbreaks have occurred simultaneously in geographic sites great distances from each other, where direct contact between those sites was not possible.3 The mystery has been such that 1 reputable journal has published a theory arguing for viruses from space, via cosmic dust, as being responsible for influenza epidemics.46 
 +\\ 
 +\\ 
 +  decrease in UV-B levels (from air pollution)..avianflu  The very minute amount of UV-C reaching the ground is likely insufficient to have a deleterious action on viral DNA and probably does not account for the seasonal occurrence of epidemics in the temperate climates. UV-B also has antiviral activity—much weaker than UV-C—but makes up 1% of the light spectrum that penetrates the earth’s atmosphere. As such, it is exponentially more abundant than UV-C at ground level, by 6 orders of magnitude. A decrease in UV-B levels (from air pollution) has been theorized to be a factor in the avian influenza epidemic.47
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===== CONCLUSIONS ===== ===== CONCLUSIONS =====
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 +  Block and Burn = Mask and UV !!!
 +  attacking virus in environment, rather than in the patient.
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The modalities proposed in this article, face masks and UV-C light, are clearly an inferior strategy compared with an effective vaccine and antiviral agents for influenza A. What is offered here is a plan B, should plan A fail. The tactic proposed is one of “block and burn”—masks to block and UV irradiation to burn the viral pathogen. The focus is on attacking the virus in the environment, rather than in the patient. The modalities proposed in this article, face masks and UV-C light, are clearly an inferior strategy compared with an effective vaccine and antiviral agents for influenza A. What is offered here is a plan B, should plan A fail. The tactic proposed is one of “block and burn”—masks to block and UV irradiation to burn the viral pathogen. The focus is on attacking the virus in the environment, rather than in the patient.
3-med-tech/uv-mask/uv-disinfect.1247491024.txt.gz · Last modified: 2009/07/13 20:17 by admin
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