Friday, May 30, 2014

Week One Day Four: The Chickie Buffer

After starting the ICP- OES, I created 5 mL samples including 50 uL of the samples provided that consist of DNA with 1 mM Cobalt2+ and varied amounts of Sodium+ ions dissolved in a solution of KCl and Tris. The samples had sodium amounts from 0 to 80 mM. The samples were run with the calibration of cobalt, sodium and phosphorus that were created previously. I had the chance to modify the method for this run from the method used yesterday. The ICP was then put on standby for Monday and I have several graphs to make on Monday based on the data from today's run. Hopefully I can put a few of them in on Monday once they are completed.


I almost forgot to mention a revelation I had while Prof. Andresen was explaining the physics (mostly thermo) behind what we are attempting to do. For over ten years, studies have been undertaken to determine why, under certain conditions that I don't remember exactly, DNA will attract another DNA even though they are both negatively charged. The Poisson- Boltzmann equation fits what is observed except for the attraction part. In lab, we are trying to evaluate what is causing this attraction. This leads to my revelation, Prof. Andresen explained this to me today and all I thought about was a scene in Chasing Liberty (a movie about the president's daughter on an adventure in Europe) and the part where the president's daughter was a "Chickie buffer (that) negates the potential for man-touching-man discomfort" so that the two guys in the movie could hug with her between them. So this summer, I am trying to find the chickie buffer!

Week 1 Day 4

Today I delved into some LabVIEW code that we will be using for our magnetic tweezers setup. We identified the sub VIs pertaining to motor control and basically figured out how they work. We also identified possibilities for future motor control.

Thursday, May 29, 2014

Summer 2014: Magnets, DNA, and Fun!

Abby and Steve hard at work in our newly created student office!
The summer has begun with two great new students (and the same old professor). We have a couple of great projects going on this summer from building a new instrument from the ground up to continuing our quest to understand the physics behind DNA packing! (In fact they have gotten some posts in ahead of me below.)

Week 1 Days 1/2/3

Day 1
I began by familiarizing myself with the programming language LabVIEW. I had done a little bit of programming before this, mostly in MATLAB and java. LabVIEW is very different than these other languages, in that it is a graphical (visual) programming language. Instead of the code being written, it looks like a circuit diagram. LabVIEW has several advantages over traditional programming languages is that there is no real compiler. Errors also tend to be easy to find as the interface won't even let you run the code if there is an error present, and shows you the error. I made several simple programs from a tutorial that introduced LabVIEW concepts. Such programs include one that determines whether or not to hire someone based on their grade, a conversion of a numbered grade to a letter grade, and a decision maker based on a machine's running temperature.

Fig 1: This is an example of the decision maker program. The top shows the front panel of LabVIEW, which displays the output of the code. The bottom is the block diagram, the code itself. For an input temperature and current machine speed, the code determines if the machine is running too hot. If it is not running too hot, it allows the machine to speed up.

Day 2
I continued my familiarization with LabVIEW by writing several programs that created a sine signal and then applied noise to it. One program filtered the noise out and produced a filtered sine signal and displayed both the unfiltered and filtered signal for the user. Another allowed the user to create an rms form of the sine wave and displayed a table of the rms measurements for the user. I also created a program which allowed the user to save data and selected data points of peak to peak measurements of the filtered sine wave to a text file.
Fig 2: This program creates a sine signal and then adds noise to it. The unfiltered sine signal is displayed for the user graphically in the front panel. The signal is then filtered and displayed for the user. The code displays a warning signal to the user for peak to peak measurements of the filtered signal that are above a threshold. The user also has the option to press a button on the front panel that allows them to save certain data points to a text file.
Day 3
I read several papers on the principles and design of a magnetic tweezers (MT) experimental apparatus. I discovered that multiple methods exist for the tracking of the beads used in MT applications. I also familiarized myself with the physics behind MT.

Week One: Day Three

I started up the ICP with help from Prof. Andresen, including putting new tubing on the Peristaltic pump. I ran a calibration set for 50mL solutions comprising of 0-500ppb of Na, Co, and P for a total of six calibrations. These were also used as the samples. In the afternoon, I read through the software manual and then Prof. Andresen and I reprocessed the samples from the morning and reviewed the data.