Sunday, October 8, 2017

IAQ radio interview with Andrew Streifel U of MN

Andrew Streifel - N. Carlson
I've had the pleasure to work with Andrew Streifel for over 30 years, first as a graduate student and then as a co-worker at the University of Minnesota Department of Environmental Health and Safety.  He is a prolific author of journal articles, an excellent speaker and the go to consultant for hospitals around the world when they are trying to solve a difficult infection control problem.

In the summer of 2017, he was interviewed on IAQ Radio discussing aspects of health care acquired infections, formerly known as nosocomial or hospital acquired infections.  In IAQ Radio Episode 470 Andrew Streifel, he reviewed the major areas of concern including infection sources, sampling methods and case studies of patient infections.

This is a list of just some of the factors mentioned that contribute to health care acquired infections:
  • The clothing worn by guests visiting a patient can be contaminated with spores from the outdoor air.
  • The previous occupant of a patient care room may pass their infection onto the next patient. Therefore, the quality of surface decontamination between patients is critical. 
  • Improper installation of building filters allows outside air to by pass the filters. 
  • A negatively pressurized building can bring in unfiltered air into the patient care area. 
I hope you get a chance to listen to the full interview. It provides many helpful suggestions for investigating health care acquired infections.

Andrew Streifel on IAQ Radio - 1 hour

Sunday, August 13, 2017

Flir-one pro IR camera

Photo of a slot supply diffuser with two small water leaks in blue on the lower right - N. Carlson
I have been pleased with the original FLIR ONE IR cell phone camera attachment and decided to upgrade to the FLIR ONE PRO as the resolution was increased by a factor of four and the upper end of the temperature range increased to 400C.  

Notes: The Android phone adapter is a C connection which has a benefit in that the camera can be orientated front or back.  The attachment will require an adapter for older phones like the Samsung J7 or the S5. The type of adapter will depend on the type of phone.  After my first attempt at purchasing an adaptor failed, I contacted FLIR and they identified the specifications for the adaptor.  I needed an Type C OTG Adapter, USB C Female to Micro USB Male OTG (On the Go) Converter Charging Data Sync Adapter . It cost less than $10. 

Issues: The FLIR ONE app will occasionally freeze up or fail to recognize the attached camera.  This problem has become less common the more I use the camera.  The new FLIR ONE app is better than the original with some helpful videos on areas where the camera may be useful.  The variety of color pallets for viewing the image provides a way of selecting the best color temperature contrast. 

Supply air diffuser with spot temperature read out.  - N. Carlson
There will be more posts in the future as I get to know the instrument better.   

Cherry mold

Mold growth on red cherry - N.Carlson
Never pass up an opportunity to identify mold on food.  I purchased a bag of cherries a couple of days ago at a local grocery store.  The rest of the fruit I examined did not show mold growth.

I used a clear 3M red tartan Scotch tape with 85% lactic acid mixed with a small amount of lacto fuchsin stain. The photos were taken with a Samsung J7 camera using an AmScope microscope.

Growth of Alternaria spp. and Cladosporium spp. taken from a tease tape sample of the cherry - 400x - N. Carlson
This would be a fairly easy mold to identify for an introductory mold class.

Monday, June 5, 2017

Handwashing guidelines for Farms, Fairs, and Fun

Handwashing is important to minimize the spread of  germs when visiting a farm or a petting zoo this summer.  Information below is provided from UMASH and the Minnesota Department of Health. This UMASH site links to a printable pdf of the poster Don't Spread Germs - Wash Your Hands!

Handwashing video of approximately 2 and 1/2 minutes

Friday, June 2, 2017

Sunday, March 12, 2017

Water leak detection with FLIR one IR camera

IR image reveals blue areas noting water damage near bathroom water leak - N. Carlson

Infrared photo to the right of the door - N. Carlson
Part of the base cove has been removed in this photo to check for water damage.  Note that water damage is suggested by the lighter blue color in this FLIR one image in areas further to the right where the base cove has not been removed.

IR photo of same wall with a different color contrast - N. Carlson

Infrared imaging helps explain location of fungal growth on exterior wall

Flir One infrared image of exterior wall Feb 2017 - N. Carlson
The blue and purple colored areas are colder than the yellow and red areas on this infrared photo taken with a FLIR One infrared camera attached to a Samsung cellphone.

Dark areas of mold growth on an exterior sheetrock wall.
The space was used to store books and other materials.  The interior relative humidity was measured at 46%.  This allowed for condensation on the metal roof deck and for the equilibrium relative humidity on the sheetock over the metal studs to be greater than 70%. 

Energy collecting windows - U of Minnesota research

Luminescent Solar Concentrator - Steven Shimizu

Current silicon solar cells have an efficiency of 25%.  These cells are opaque (do not allow light to transmit through). Please see Standard silicon solar cell parameters (PV

In a luminescent solar collector, the quantum silicon dots embedded or painted on transparent glass reflect light to the perimeter of the glass where solar collectors convert the light into energy.  This allows a window in a building to also work as a solar collector. Because silica is not an element in short supply, this allows for low cost and low efficiency (2.5 to 5%) solar energy collection. 
The U of M Brief publication article on Energy Collecting Windows now a Step Closer to Reality 
describes the process researchers used to construct the window based solar collectors. The abstract,
Highly efficient luminescent solar concentrators based on earth-abundant indirect-bandgap silicon quantum dots provides more information.  

The Clean Energy Institute lists resources and materials needed to construct a Luminescent Solar Concentrator.

Windows that collect solar energy - 2 min.

Sunday, December 25, 2016

Reasonable cost mycology microscope

I am currently setting up a small micro lab at home as I am taking care of someone on medical leave.  I wanted to find a reasonably good quality microscope that allowed me to read samples but cost less than $1000.  I settled on an AmScope T720 40X-1000X Plan Infinity Kohler Laboratory Trinocular Compound Microscope from Amazon and purchased it with regular shipping for less than $600. 

The trinocular scope has a 10x eyepiece with 4x 10x 20x 40x and 100x Plan nose pieces.  I stayed away from the 20x eyepiece on other models as any magnification without oil over 400x tends to be a bit blurry.  The 200x magnification really speeds up a scan of the field with a bit more clarity than the 10x and more area than the 400x,  The LED light works well as does the stage operation. I may later purchase a digital camera for the top mounted lens.

One minor issue with the scope.  It does not maintain perfect focus when transitioning between different magnifications.  On the plus side it has eye correction adjustments for both eyepieces.  The field of vision is good and the ergonomics of the scope is sound even though I chose not to pay for a model with a tilting eye piece.

Alternaria spp. and Penicillium spp. spores 200x - N.Carlson

The above photo was taken with a Samsung Galaxy S-5 smart phone through the eyepiece of the microscope with magnification at 200x.  This is definitely good enough to pick out spores during an initial scan of both and Air-o-cell cassette trace or a tease tape sample. This was a tease tape sample taken from a swab. 

Friday, November 25, 2016

Foldscope kickstarter program

Foldscope microscope -

Foldscope has launched a Kickstarter program for its next round of origami foldable microscopes with a 140x lens.  Sign up at Foldscope Kickstarter to purchase the microscope.  The lower cost sponsorships are no longer available.  Microscopes in lots of 20 can still be obtained for less than $2 per scope.  The current low cost project is $30 for a teacher's kit.  It includes 20 microscopes plus a teacher microscope with case.  The cost for shipping will vary depending on the location. 

I recently used this Foldscope in the field as part of a mold investigation.  I magnetically attached a Foldscope  to a Samsung S-5 cellphone.  The researcher and our Facilities Management representative could then view the magnified image of the mold Cladosporium spp. growing on the supply diffuser.  

Supply diffuser with suspected mold growth.

Original Foldscope image unmagnified

Foldscope image of Cladosporium spp. magnified and enhanced with Adobe Photoshop Elements 12.