4 ms·

Well if the first one is a no, then the second one is obviously a no since that method isn't used. Find more on virus measurement methods here: https://www.camb

Well if the first one is a no, then the second one is obviously a no since that method isn't used. Find more on virus measurement methods here: https://www.cambridge.org/core/journals/parasitology/article/sizes-of-viruses-and-the-methods-employed-in-their-estimation/BA71C94D73307F5CA7C63753135507F9 https://www.cambridge.org/core/journals/parasitology/article...

DoctorOetker 7y ago
"this" in the second sentence refers to droplet size regardless of measurement method. I have asked for the SARS-CoV-II droplet size distribution many times before, for example here: https://news.ycombinator.com/item?id=22519323 https://news.ycombinator.com/item?id=22519323
- thatcat 7y ago
  The droplet size distribution would be for saliva, covid19 would effect this less than say cough velocity or other variables. The volume of fluid produced does seem to change with illness and influenza may increase the total volume produced in a cough with 63% of the particles in the size range of 0.35 to 10 μm as measured by a laser spectrometer in an influenza infected patient. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4676262/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4676262/
  - DoctorOetker 7y ago
    what I mean is that droplets produced in the lung are not necessary saliva, and droplets produced in the nose, .... all have varying viscosities depending on flu or cold, dry cough or not, ... think about what you are saying, how could what you say be true, and some diseases be more air borne than others? if a pathogen can trigger specific immune responses that result in runny noses, or blocked noses it has some control over the viscosity of different types of mucous our body produces... so has this droplet size distribution been measured for covid-19?
    - thatcat 7y ago
      I mean it's not completely senseless to compare unknown psd to known psd of sick people. It just seems that as a diagnostic metric it doesn't seem to give you much new information and would be too error prone. My thoughts were about fluid dynamics and what causes a particle with a mass greater than air to become airborne in the first place - force of updraft jet on surface area overcomes the force of weight, right? So that'd be determined by the velocity of the air flow and the properties of the fluids interacting. So you'd have to first either measure velocity of the ejection or make an estimate and you'd pick a sensor to measure the different particle sizes. Those sensors typically only give a range of particles as output such as <2.5u, <10u, etc in ppm. You'd be forced to group the distribution into discreet intervals and accept more inherent sensor error. Then you have a non-homogeneous fluid with insoluble solids in it launched at variable velocities each time so you probably would need multiple samples (how many to overcome this variance? Can you do it with out over powering your analysis?). Whether the data was useful would depend on some really good designs that minimize the variance of the samples. It would be an interesting experiment, but I doubt you would find statistically significant results between the different illnesses based on runny noses vs blocked noses viscosity change. I don't think you really need to though because runny or blocked nose is already a diagnostic symptom that doesn't require particle size distribution to determine.

DoctorOetker 7y ago

"this" in the second sentence refers to droplet size regardless of measurement method. I have asked for the SARS-CoV-II droplet size distribution many times before, for example here: https://news.ycombinator.com/item?id=22519323 https://news.ycombinator.com/item?id=22519323

thatcat 7y ago
The droplet size distribution would be for saliva, covid19 would effect this less than say cough velocity or other variables. The volume of fluid produced does seem to change with illness and influenza may increase the total volume produced in a cough with 63% of the particles in the size range of 0.35 to 10 μm as measured by a laser spectrometer in an influenza infected patient. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4676262/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4676262/
- DoctorOetker 7y ago
  what I mean is that droplets produced in the lung are not necessary saliva, and droplets produced in the nose, .... all have varying viscosities depending on flu or cold, dry cough or not, ... think about what you are saying, how could what you say be true, and some diseases be more air borne than others? if a pathogen can trigger specific immune responses that result in runny noses, or blocked noses it has some control over the viscosity of different types of mucous our body produces... so has this droplet size distribution been measured for covid-19?
  - thatcat 7y ago
    I mean it's not completely senseless to compare unknown psd to known psd of sick people. It just seems that as a diagnostic metric it doesn't seem to give you much new information and would be too error prone. My thoughts were about fluid dynamics and what causes a particle with a mass greater than air to become airborne in the first place - force of updraft jet on surface area overcomes the force of weight, right? So that'd be determined by the velocity of the air flow and the properties of the fluids interacting. So you'd have to first either measure velocity of the ejection or make an estimate and you'd pick a sensor to measure the different particle sizes. Those sensors typically only give a range of particles as output such as <2.5u, <10u, etc in ppm. You'd be forced to group the distribution into discreet intervals and accept more inherent sensor error. Then you have a non-homogeneous fluid with insoluble solids in it launched at variable velocities each time so you probably would need multiple samples (how many to overcome this variance? Can you do it with out over powering your analysis?). Whether the data was useful would depend on some really good designs that minimize the variance of the samples. It would be an interesting experiment, but I doubt you would find statistically significant results between the different illnesses based on runny noses vs blocked noses viscosity change. I don't think you really need to though because runny or blocked nose is already a diagnostic symptom that doesn't require particle size distribution to determine.