Professor Hendrik Dietz by Becca Landry

    Professor Hendrik Dietz holds the position of Full Professor for Biophysics at the Technische Universität München (Technical University of Munich) where he is also the Principal Director of the Laboratory for Molecular Design. He has an extensive educational background, having graduated with degrees in Physics from Universität Paderborn in Germany, Universidad de Zaragoza in Spain, and Ludwig-Maximilians-Universität München in Germany, with a thesis in “Mechanik des Grün Fluoreszierenden Proteins” (Mechanics of Green Fluorescent Protein) from the latter. He also earned his doctorate in Physics from where he works now with the thesis “Mechanische Anisotropie einer Proteinstruktur in Einzelmolekülexperimenten” (Mechanical Anisotropy of a Protein Structure in Single-molecule Experiments). 

    I chose to write this prompt about Dietz after finding an article about his recent research. In that project, he and other physicists created DNA origami molecular rotors in an effort to recreate the molecular machinery of life and its efficiency in rotation. DNA origami is done by “sequence-programmable DNA self-assembly” where many base pairs are lined up and put into a solution to form a 3-D structure independently given their code, and structures are confirmed via cryo electron microscopy. This electrical motor rotates by applying an alternating current electric field. Future ideas with this work include looking into using chemical fuel to power the rotation, or alternatively, researching the use of rotation to “drive uphill chemical synthesis.” His lab is also working on creating structures, again using DNA as building blocks, to trap viruses within the body to prevent the infection from spreading. They are currently performing in vivo efficacy tests to better understand how to apply this new technology to contain infection in mice. 

Sources:

https://www.youtube.com/watch?v=sdeu2XGcKyU&t=1425s 

https://www.dietzlab.org/ 

https://physicstoday.scitation.org/do/10.1063/PT.6.1.20220818a/full/

Elon Musk by Eric Goodney

 

How velocity controls erosion and deposition at the Chenango River

Recently, I visited a spot on the Chenango River, about 15 minutes from Colgate, as a TA for a geology class. While the students were making observations about the river, I too began to take note of its key feature. One thing in particular that stood out to me was the velocity of the river. The Chenango River is a meandering river (is made of sinuous repeating curves) and therefore the velocity is not constant in the streambed. Instead, the velocity of the channel is dependent on how much resistance (by friction force) is acting upon the water. 

At the Chenango River, I noticed that the water moved the fastest in the center of the channel. This is because the water is the deepest and experiences less resistance. In addition, the curves or bends that characterize a meandering river create a series of point bars and cut banks based on the velocity of the water. On the outer curve, the banks are highly eroded (creating a cut bank) because the velocity is the highest. The Hjulstrom diagram shows that erosion of larger grain sizes occurs at higher velocities. On the inner curve, point bars form by the deposition of sediment at lower velocities. The Hjulstrom curve shows a relationship between velocity and grain size where the velocity of the water decreases and therefore the grain size also decreases. The decreasing velocity causes the deposition of large grain sizes on the inner curve creating a point bar.

The theoretically highest final velocity gained from Colgate Hill

    One of the things that most of us have to do every day is make our way up Colgate’s hill. It is a somewhat strenuous endeavor, and since I like to bike to class it has become a bit of a hassle. However, what makes it worth it to me is the thrill of the ride down. As gravity takes the reigns, you are sent speeding down the twisting roads of campus, all the way until you reach the bottom at James C. Colgate Hall. Ever since I started taking physics, I have always wondered: “What if I threw caution to the wind and never braked during my descent? How fast would I truly be going and how many injuries would I get if I fell?” So after discovering this outlet to share my findings, I started my journey to figure out the speed I could theoretically obtain on this otherwise mundane drive down a regular old hill.

The first idea that came to mind when I was pondering over the aforementioned questions was a simple one. Just time yourself going down the hill, and never use the brakes. Then just use the kinematic equation vf=v0+at. With a= 9.8m/s2 and V0= 0 m/s, then plugging in time to figure out the final velocity. However, there lies a single brutal flaw in this plan, I, like many physicists, value my safety and do not want to become a red smear on the road. So, I pivoted to the much safer and mathematically strenuous idea of using forces to calculate the final velocity.

The first thing I did was set up a situation and gather the data needed for the calculations. Using Google Maps, I found that the highest point on campus that had the data I needed was the Coop, and the lowest point at the end of the hill was James C. Colgate Hall. So I created the route and found the distance and height of the trip. Shown below.

Using this data I could create a diagram showcasing the forces present on the trip, Which I have shown below

We can use trigonometry to find some values, mainly ΘF, ΘS, Fgx and Fgy.

We also know that Fg=mg, therefore we can make the equations

Fgx=mgsinΘF

Fgy=mgcosΘA

We can also find ΘA since ΘA and ΘS make a 90º angle, which makes ΘA=2.87º. Notice how it is the same as ΘF, this is true for all problems like this. 

We can assume that Fn will have the same magnitude as Fgy thanks to Newton’s third law(Every action has an equal and opposite reaction), just in the opposite direction.

Therefore:

Fn=-Fgy.

We can calculate all of these forces right now, but to simplify things later, we will refrain from doing so.

The only force that is left to calculate is Ffr, which according to our textbook is:

Fgx-µkFn=Fr

Unfortunately, µk for my bike is different than the gravitational constant given in our textbook for rubber on asphalt because my bike uses wheels, which are affected by rolling friction. After much research into rolling friction or rolling resistance, I have decided to spare you the details, and instead, use a coefficient found online for bike tires on asphalt(0.004)1.

We can then calculate my bike’s acceleration using the simple equation:

Fgx-Ffr=max.

By plugging in all our knowns we are left with the formula:

mgsinΘF-µk(mgcosΘA)=max

Since every part of the equation has mass(m) in it, we can cancel out mass and get this equation, which is why I refrained from calculating anything earlier.

gsinΘF-µk(gcosΘA)=ax

Plugging in our values with ΘF and ΘA =2.87º and µk=0.004. We get an acceleration of

0.45m/s2!

This at first glance seems a bit small, but consider that this is over a 900meter distance, and we can use the kinetic equation Vf2=V02+2a(Δx).

Assuming an initial velocity of 0, we get a final velocity of

28.5m/s!

For reference, 28.5m/s is equivalent to 63.7 mph!

63.7mph is something you would be more likely to see on a major freeway, not from some random hill on a college campus, and a fall from that speed would leave you with more than just a scratch.

So if you were to take anything from this Physics journey, Make sure you keep your brakes in top condition and wear a helmet!

Displacement and velocity of running by Eric Goodney

 One of my favorite things to do in my free time is to exercise, with my favorite activities during the summer months being running and cycling. After completing the first full week of Physics 111, I have become more aware of the physics involved in my activities and have even become surprised regarding certain statistics. Here is a screenshot of a run I did this summer from strava, an app that tracks physical activity. This particular loop took place at the beach in York Maine.

I started my run at my beach house located in the bottom left corner of the strava map. I then ran along Long Sands beach and took a sharp right to head toward Nubble Lighthouse. Once at the tip of the peninsula, I turned around and headed back home.

I am now able to better understand the physics of this activity. I now realize that some statistics of my run are not so impressive. Having learned that displacement is the change in position, my run had a displacement of zero miles since my final and initial positions were the same. Consequently, my run had an average velocity of zero miles per hour due to average velocity being defined as the change in displacement over time.

I have also realized that even if I had ended my run at Nubble Lighthouse, the magnitude of my displacement would be less than the distance I traveled. This makes sense visually, looking at the map, as my distance traveled took place roughly over the shape of two sides of a triangle, whereas my displacement would have been the hypotenuse of that triangle.

I look forward to learning more physics to describe other activities I enjoy, like alpine ski racing. I hope to learn how the force of gravity, friction, and the normal force are involved in skiing down a slope.

Professor Alicia El Haj

 

Professor Alicia El Haj currently holds a position in the Healthcare Technology Institute in the Institute of Translational Medicine at Birmingham University as an Interdisciplinary Professor of Cell Engineering. She earned her Masters at the University of Manchester and a Ph.D. at the University of Aberdeen. She had previously served as the founding Director of the Institute of Science & Technology in Medicine at Keele University Medical School. Additionally, Professor El Haj is the Director of MICA Biosystem, Ltd. which takes in vitro pharma screening tools and stem cell control systems and adapts them for clinical use, among many other previous and current leadership roles she holds. With all of these accomplishments, she earned a Royal Society Merit Award in 2014 and the MRC Suffrage Award in 2015 for her role in leading women in STEM. Professor El Haj is fighting gender imbalances in the larger STEM field, working towards a healthier workplace environment, increasing the visibility of women and their achievements through an online database, and creating an equitable platform for professional development. She does this through the Women in Medical Physics and Biomedical Engineering (WiMPBME) Task Group, under the International Union of Physical and Engineering Scientists in Medicine, which was established in 2014 to coordinate tasks and projects internationally, supporting women in medical physics and biomedical engineering. 

Professor El Haj is interested in aspects of cell and tissue engineering and regenerative medicine and strives to move innovative new cell-based therapies to the clinic, including biomechanics, bioreactors, and imaging systems. Her most current research project is titled “SHIFT: Shaping Innovative Designs for Sustainable Tissue Engineering Products” which aims to use green chemistry principles to minimize the research's environmental impact. The objective of this project is to design several devices consisting of natural-based, scalable constructs that enhance angiogenesis (the development of new blood vessels) to treat widespread chronic pathologies, such as large defects in bone and cartilage, and the treatment of chronic wounds. 

https://www.keele.ac.uk/pharmacy-bioengineering/ourpeople/aliciaelhaj/ 

https://research.birmingham.ac.uk/en/persons/alicia-el-haj 

https://link.springer.com/article/10.1007/s12553-022-00658-7 

https://cordis.europa.eu/project/id/101008041