Sterlitech Blog

We've previously discussed how the combination of silver and carbon nanotubes can be used to create more efficient water purification filters, now you can see a little bit about how this filter is made thanks to Technology Review and Stanford University. You can read more about the process here.

When counting bacteria as part of epifluorescent microscopy we generally recommend using the black polycarbonate membranes instead of cellulose membranes. This is because the black polycarbonate materials have a uniform pore size and flat surface that will retain all of the bacteria without trapping any inside of the filter. Though cellulose membranes will retain bacteria, it often will become trapped inside of the filter, where it cannot be counted.

Is nothing sacred? In the news today came word that the period table is changing the atomic weights of 10 elements. Instead of being listed as one static value, the atomic weight for these elements will now be displayed as a a range that will more accurately reflect how the elements actually appear in nature.

The change is being made after decades of study and this is the first time in the history of the periodic table that any atomic weights will be altered. Measuring the variance of atomic weights is being used in real world applications for everything from analyzing food purity, to determining which athletes are using performance enhancing drugs!

The elements being changed are: Boron, carbon, chlorine, hydrogen, lithium, nitrogen, oxygen, silicon, sulfur, and thallium.

I hope this doesn't mean we'll have to memorize the table all over again...

You can read more about the change here or here.

We created a handful of brief product videos last week to show you all some of our equipment in operation. First up is the Mini Centrifuge.

...then we have the Magnetic Stirrer. Seen here making some delicious blue water...

...next up is the Benchmark Digital Dry Bath so you can get an idea of how clear the display looks...

...and finally we have the Bactizapper Infrared Micro Sterilizer. It may look small, but don't be fooled, this model can produce temperatures up to 815 C!

Recently one of our customers was interested in testing Legionella bacteria and asked us how our polycarbonate membranes fit into the process mentioned on our website. If you are unfamiliar with Legionella, it is a waterborne pathogen commonly found in aerosolized waters such as cooling towers, showers, and humidifiers, and it is best known as the cause of Legionnaire’s Disease as well as Pontiac Fever. Its name originated from an outbreak that occurred at the 1976 convention of the American Legion in Philadelphia.

There are actually two areas in which membranes are used in regards to Legionella: Sample preparation and point-of-use filtration. For sample preparation the CDC (Centers for Disease Control) recommends using a 0.2 micron, 47mm polycarbonate filter to extract Legionella bacterium from potable water. Non potable water utilizes a direct plating procedure.

Point of use filtration frequently involves a device that attaches to a faucet or showerhead to eliminate Legionella. Such devices have filters built into them, usually made of Nylon or PFT. A few years ago the American Journal of Infection Control conducted a study of these devices and found them to be extremely effective at preventing the spread of waterborne pathogens.

For more information on Legionella testing and guidelines, you can visit:

http://www.cdc.gov/legionella/files/legionellaprocedures-508.pdf
http://www.specialpathogenslab.com/SPL-Advantage/AJICFilterpaper05.pdf

The good people at ASTM (American Society for Testing and Materials) have released their standard for determining the Silt Density Index of water. If you're interested in learning more about it, you can preview the document here. You can also look at our very own SDI test kits here.

We just got blasted with our first winter storm of the year and it was a mean one for Seattle.  Take a look at the video and you can tell that while there are many things we do well here (computer programming, watching soccer), driving around in the snow clearly isn't one of them.  Even our own metro buses can't quite get the hang of it!

Just a reminder, but Sterlitech will be closed this Thursday and Friday for the Thanksgiving holiday (November 25th and 26th. We will open again on Monday the 29th. We wish you all a safe and happy Thanksgiving!

Here is an article that does a great job of explaining what efficiency ratings mean on a filter and how they are calculated, courtesy of the American Filtration & Separation Society.  This is very useful information for filter users and purchasing agents on the practical effects the filter efficiency will have in a real world setting.