Br i n g Back an Ex ti n ct Rh i n o Su bsp eci es

CarolineChu

On August 6th, 2022, a new southern white rhino calf was born at the San Diego Zoo Safari Park?s Nikita Rhino Rescue Center. W hile this new m ale calf is of a different subspecies, he m arks the next step in bringing back the northern white rhino from near extinction. The last rem aining m ale northern white rhino died in M arch 2018, and the two rem aining fem ale northern white rhinos live in Kenya, but they are past reproductive age The m other of the new southern white rhino calf at the San Diego Zoo is Livia. She is a first tim e m om , and the successful birth of her calf proves that Livia is able to carry a calf to term and care for the calf This m akes Livia a vitally im portant rhino because she is one of three southern white rhinos at the zoo who could potentially be a surrogate m other for a northern white rhino em bryo.

Not only could Livia be the surrogate, she was also closely studied so that researchers could gain m ore knowledge about the southern white rhino?s reproductive cycle. They collected data on when the reproductive cycle begins as well as the phases. This inform ation will be applied in the future and will allow researchers to be prepared as they plan to im plant a northern white rhino em bryo into a southern white surrogate m other in the hope that the surrogate could give birth to a genetically pure northern white which will provide the foundation for repopulation

The stem cell biologists plan to use northern white rhino tissue from the San Diego Zoo W ildlife Alliance?s ?frozen zoo,?the largest cryobank in the world of anim al cells, to create a northern white em bryo. The cryobank contains skin cells from twelve different northern white rhinos which they believe is enough to create a healthy and genetically diverse rhino population. However, the challenge is that researchers are having to design the em bryo creation process from scratch They even have to design basic steps such as the correct petri dish culture, the nutritional layer of the petri dish that will allow a fertilized egg to grow.

San Diego Zoo W ildlife Alliance researcher Carly Young said that the biologists used protocols developed from the horse, dom estic cat, deer, and even hum ans to create the m aturation m edia for the northern white rhino.

Before anything else, however, scientists have to be certain that their procedure will work correctly in southern white rhinos before they begin using any of their lim ited supply of northern white cells W hile Germ an scientists have already created northern white em bryos using eggs from the two rem aining northern white rhinos, they were unable to successfully transfer em bryos. However, the San Diego Zoo is m aking progress. Two of their rhinos have already gotten pregnant from artificial insem ination which was a first for zoos in North Am erica The insem inations using frozen sperm allowed researchers to learn even m ore about the rhino?s reproductive cycle because the rhinos were trained to have ultrasounds and other health checks, giving researchers the chance to take crucially im portant m easurem ents of the fetus

The northern white rhino skin cell sam ples are stored in nitrogen cooled freezers where stem cell biologists attem pt to get northern white rhino stem cells from these skin sam ples. Stem cells are the m ost basic form of cells and are what all other cells develop from .

However, researchers only have skin cells not stem cells, and this created a m ajor issue. Skin cells, like all other types of adult cells, cannot turn into other kinds of cells once developed However, the inform ation to develop into different types of cells is still in the genetics of the skin cells, so theoretically the researchers could use that to create stem cells.

To access those genes, researchers m ust first perform steps to reset and rem ove all of the cell?s program m ing to return it to a stem cell This process has been perform ed on the cells of other anim als and also hum ans, but never before on rhinos. There are four regulatory m olecules that are known as Yam anaka factors which are needed to reset a skin cell These factors control the way that DNA is copied for translation into other proteins. In 2021, the San Diego Zoo?s researchers were able to create one northern white stem cell from 100,000 skin cells. Since then they have m ade adjustm ents to increase efficiency that allow them to create seven stem cells from 100,000 skin cells, and while this process still has to be optim ized, the fact that they have been able to m ake even one northern white stem cell is im pressive. Since adult stem cells can becom e any cell in the rhino?s body, stem cells allow for the creation of em bryos. W hile researchers have been able to accom plish the creation of em bryos from stem cells in m ice, it has never been done before in rhinos The researchers collected skin cells from the last m ale northern white that was kept at the San Diego Zoo, and using these cells, the biologists were able to develop them into rhino heart cells. The cells, called cardiom yocytes, even expand and contract on the Petri dish naturally. These heart cells are a m ajor source of hope for the im plantation of northern white em bryos into the southern white surrogates

The second step to creating an em bryo is developing the stem cells into prim ordial, the earliest stage of cell developm ent, sperm and eggs The process of turning stem cells into sperm and egg cells is incredibly difficult. It requires sending intracellular signals at the perfect concentration, tim ing, and duration to m ake the stem cells turn into the desired type of cell The intracellular signals could be growth factors or certain chem icals that turn on or off pathways during the cell cycle. The researchers can then use the signals to direct the cell to turn into specific genes Once created, however, keeping stem cells healthy and alive is difficult. If the cells aren? t fed frequently, the growth factor m akes the stem cells m aintain their stem cell state, and then they will break down. The stem cells are also highly sensitive to heat which requires constant m onitoring of the tem perature which m ust rem ain at -321degrees Fahrenheit or else the cells will die. The stem cell biologists have developed the tedious care instructions necessary and have already yielded spectacular results.

Step three is fertilizing the egg with the sperm , both created from stem cells, to create an em bryo. The first requirem ent for fertilizing an egg is to have an alive and m ature egg and sperm However, scientists m ust now create the perfect environm ent for the egg to grow because the egg wouldn? t be inside of the ovaries The scientists have to learn to recreate the ovarian environm ent?s ?Goldilocks Zone?which is a perfect tem perature, horm one and nutrient concentrations, and ratio of gasses such as carbon dioxide and oxygen that allows the eggs to grow. To find this rare Goldilocks Zone, the scientists first experim ented with southern white rhino eggs The team at the zoo had previously only had access to eggs harvested after a southern white had passed away, and these eggs were not as healthy as those from living rhinos. In M arch 2020, the team m ade great progress and was able to successfully harvest 22 live eggs They achieved a 50%m aturation rate and produced an em bryo in an im pressive first attem pt.

The fourth step, the im plantation of the northern white em bryo, is where southern white rhinos like Livia com e into play. The fetus will grow and develop in the wom b of the southern white. This step, although it m ay sound sim ple, also presents m ajor challenges. The wom b has a dynam ic nature, and in order to support a growing fetus, the em bryo and the wom b have to be in sync with one another.

The researchers used ultrasounds to learn how to synchronize the wom b and the fetus The rhinos were trained to willingly participate in the ultrasounds The zookeepers have perform ed over 1,000 ultrasounds and have gained significant am ounts of data about the reproductive system .

The data was used to learn when in their cycle rhinos are m ost likely to accept an em bryo transfer Researchers have also developed a series of horm one treatm ents which increase a rhino?s likelihood of accepting an em bryo by inducing ovulation within 48 hours. As a sign of the researcher?s new discoveries, in 2019 two southern whites were artificially insem inated and gave birth to healthy calves. Livia has now joined them as possible surrogates for the northern white rhino em bryo.

The technology being developed for the northern white rhinos could even be applied for other endangered anim al species Oliver Ryder, the San Diego Zoo?s director of conservation genetics, places an im portance on the creation of ?a global network of frozen zoos?such as the one in San Diego because having skin cells of every species is like an insurance policy Should anything happen to the population of a species, there is the potential to bring the species back from frozen skin sam ples. This new em bryo im plantation research holds the secret to reviving a lost species as well as preventing others from going extinct

Bibliography

Dance, Am ber "San Diego's Frozen Zoo Offers Hope for Endangered Species around the World " Knowable M agazine Sm ithsonian M agazine, www.sm ithsonianm ag.com /science-nature/san-diegos-frozen-zoo-180971276/. Accessed 27 Oct. 2022

Rogers, Peter. "Northern W hite Rhino: Resurrecting an Extinct Species in Four Steps." Big Think, 22 M ar 2022, bigthink com /life/resurrection-deextinction-northern-white-rhino/ Accessed 28 Oct 2022

Schm iedeberg, Renee "A New Hope: Southern W hite Rhino Calf Born at San Diego Zoo Safari Park " NBC 7 San Diego, NBC Universal M edia, 23 Aug 2022, www.nbcsandiego.com /news/local/a-new-hope-southern-white-rhino-calfborn-at-san-diego-zoo-safari-park/3029120/. Accessed 25 Oct. 2022.

Three sum m ers ago, I was sitting with m y sister in our backyard, m indlessly watching Youtube? when we both saw a video of a com m ercially sold ?Sisyphus Table? It was m esm erizing: a circular coffee table with a bed of sand underneath a glass top. A m etal m arble would then effortlessly glide through the sand, being pulled by a m otorized m agnet underneath the table, leaving an intricate geom etric trail behind We were both captivated and just needed to get one, so we went to their website. The $2000 price tag im m ediately ended our hopes of ever getting one. But I thought: If I can? t buy one? why not build one?

Just one sm all problem ? I knew alm ost nothing about engineering, woodworking or really any skill needed to tackle such a project However, I blindly progressed forwards. I first needed wood for the table?s base, but plywood was too expensive so I went dum pster diving down m y street until I found a usable piece of wood I then watched Youtube tutorials on how to cut the wood into a circle using a table saw, and eventually how to program an Arduino to control Nem a-17 stepper m otors. Over the next few years, I went through m ultiple design iterations and eventually settled where the project is now? so let m e give you a quick rundown of how it works.

The inner m echanism uses two stepper m otors. One slides the m agnet back and forth on an axis using a ball screw linear actuator, and the other m otor rotates the entire axis around the center of the table. By using this approach, the m agnet can reach any point within the circle. The m echanism relies on polar coordinates, where instead of using X and Y coordinates like you would in a 3-D printer or CNC, you specify an angle and a distance from the origin, where each m otor corresponds to either value. The m otors them selves are Nem a-17 stepper m otors, which rotate in very sm all increm ents and are controlled by TM C2209 stepper m otor drivers. The stepper m otor drivers are then controlled by the ?brains?of the table, the ESP32. The ESP32 is a super inexpensive m icrocontroller akin to an Arduino, except it runs with Bluetooth Low Energy and W i-Fi built in! Using this wireless connectivity, I was able to create a m obile app using Flutter, Google?s m ulti platform app developm ent fram ework.

The app uses Bluetooth to connect the table to W i-Fi along with short actions such as pausing or playing the current design. W i-Fi is used to upload and download different track designs to and from the table with an H TTP web server. But enough with the boring technical jargon, let's talk about actually building the table.

I?ve gotten m any parts off of Am azon, and learned how to use them through online resources But som e parts of the table I had to build m yself. This is where the Innovation Lab cam e in to help m e W hen I started working on this project, I was not yet a student at Westm inster and had little to no access to proper tools and equipm ent. However, since I started m y current year, I?ve been able to utilize m any different parts of the lab. I laser cut a 345-tooth wooden gear to use for rotating the central axis I also had to 3D-print a couple parts to support the ball screw axis, house the m agnet, or m ount the rotational m otor.

One m ain goal I had in m ind while designing this project was ease of use I could have probably finished the table m any m onths earlier if I had gone with a sim pler approach by elim inating wireless features, scrapping the m obile app, and just reading files directly off of a m anually-loaded SD card. But I wanted to create som ething as close to perfect as I could so that I could be proud of it. It has been very difficult, but I?ve designed it so that even m y grandm other could use it.

Looking back three years ago at m y sister and I m arveling at the joys of art and engineering, it?s m otivating to see how far I?ve com e M y favorite part of this project has been being able to see things slowly com e together? but I?m not quite finished just yet. I still have to actually build the whole exterior of the table as I?ve only really finished the inner m echanism , program m ing, connectivity, and the m obile app. However, I have really enjoyed working on the project so far and it has given m e a m uch greater understanding and appreciation for STEM . I?m looking forward to continuing working on the table, and can? t wait to see what it will eventually becom e.

Max Scholle

FDM ax is m y custom -built 3D printer. Since Septem ber, I?ve been working to fabricate m y personalized design with m y own hands, and the experience has been as rewarding as it?s been fun Constructing FDM ax gave m e a chance to create a m achine with features com m only overlooked on the m arket, and m ore im portantly, the project taught m e invaluable lessons that proved vital to m ake it all possible

Over the two years that I owned a 3D printer, I learned plenty about how 3D printers work. I got m y first 3D printer for m y 13th birthday, and I had alm ost no idea how to operate and m aintain it by m yself. Nonetheless, I quickly learned the skills and m echanics of 3D printing, and m y 3D printer becam e one of the m ost fun and interesting things I owned. But by the tim e I turned 15, I wanted som ething better. M y Anycubic M ega S 3D printer was great, but I wanted a m achine that I could m odify, upgrade, and connect to other things, som ething that the proprietary design didn? t seem to provide. Conveniently enough, that was when I started m y tim e at Westm inster, which offered m e the resources I needed to pursue this idea

Advantages

FDM ax is m eant to im prove on all of the areas in which I noticed m y Anycubic M ega S was lacking, taking inspiration from existing products. It isn? t just Fused Deposition M odeling ? it?s Fused Deposition M ax-im ized! FDM ax offers these awesom e features to nam e a few, things that you won? t find in lots of the 3D printers on the m arket:

- Vertical bed: M any 3D printers on the m arket have beds that m ove back and forth to serve as the y-axis, but that m eans that their footprint depth is alm ost twice their bed length! FDM ax has a bed that only m oves up and down, so y-m otion m akes no contribution to the footprint.

- CoreXY design: M ost Cartesian 3D printers are built with one axis that m ust carry the m otor for another. This results in m ore work having to be done by the printer as it m oves, and therefore less speed and m ore wear W ith CoreXY, an innovative belt design allows all m otors to rem ain stationary, so the m oving parts are as lightweight as possible. (To understand the CoreXY theory, see this website that has helped m e: https://corexy com /)

- Interchangeable toolhead: 3D printers typically have a hotend, which is what m elts the filam ent and lets it flow onto the m odel However, the m otion and precision that a 3D printer offers shouldn? t be restrained to just 3D m odels; I intend for FDM ax to have plug-and-play tools in later stages, including laser engravers and even pencils, to fully take advantage of its capabilities

- Enclosure: Less-expensive 3D printers are often open-air printers, having no walls around them . H aving no walls is fine for printing in PLA (a type of plastic filam ent), but it quickly poses issues with other m aterials. W ith TPU, as I?ve observed firsthand, an open-air 3D printer releases awful fum es And with ABS, which is very sensitive to tem perature differences, the air around the m odel is too cold, causing the m odel to curl. H aving an enclosure serves to insulate the m odel and contain terrible fum es

- Integrated Raspberry Pi: W ith a Raspberry Pi, m y 3D printer would have nearly lim itless capabilities. Prim arily, it would be W iFi enabled via OctoPi, a beautiful and incredibly useful platform through which I can rem otely m onitor m y 3D printer and operate it without the need for SD cards or a connected PC Additionally, FDM ax will have a webcam , 7-inch LCD screen, and m ulticolor LED lights. Yes, FDM ax will have style!

Process

I began m ajor construction of m y new 3D printer in Septem ber (shown to the right) Originally, I intended for there to be a m eter of build length to m ake a truly m axim ized build volum e W ith the desire to im prove as m uch as possible from m y old 3D printer, I continued work on this through the winter. Som ething was terribly wrong, though.

By February, I realized that I needed to change m y approach to construction. This wasn? t new; finding what m aterials and m ethods worked best for m easuring, com bining, constructing, and realizing ideas took years of trial and error The big lesson I learned in February was that for large projects, a com prehensive design is vital for success W hen I started construction, I knew a solid design would be necessary, but I realized in February that even a bulletproof-sounding plan can topple if it?s incom plete M y lack of foresight had caught up with m e, and com pletion becam e im possible, specifically with the belt system . That?s when I began to design m ore thoroughly in an Onshape assem bly, and I did it right All of the design fit together and included the things I wanted to include, and I just needed to build it, no questions asked I finished m y design in M arch

After disassem bling the partly-built 3D printer, I im m ediately began work on the fresh new concept. Unfortunately, m y process was heavily delayed because the 3D printers in the lab weren? t operational, so I couldn? t m ake m y parts Yes, it takes a 3D printer to m ake a 3D printer

I started by creating the bed assem bly In the picture to the left, I have the com pleted bed assem bly with the Onshape design in the background The bed assem bly had two Z-steppers and carried the bed, which slid along four rails and two screws.

After the bed assem bly, I built the fram e. The fram e m ade it start to look like a real 3D printer! After securing all of the 2020 extrusions (m etal bars) together, I put the bed assem bly into place The m ost satisfying part of m aking things is when two separate pieces fit together perfectly. The fram e and bed are shown to the right.

W ith a bit m ore work, I added three m ore stepper m otors to control the XY m otion and the extrusion. After a slight design m odification (because I didn? t want to pay $15 for longer screws), I fabricated the XY gantry, the part that carries the nozzle To com plete the m otion m echanism s, I added the CoreXY belts All of the m echanism s m oved properly

I started by creating the bed assem bly In the picture to the left, I have the com pleted bed assem bly with the Onshape design in the background The bed assem bly had two Z-steppers and carried the bed, which slid along four rails and two screws.

After the bed assem bly, I built the fram e The fram e m ade it start to look like a real 3D printer! After securing all of the 2020 extrusions (m etal bars) together, I put the bed assem bly into place The m ost satisfying part of m aking things is when two separate pieces fit together perfectly. The fram e and bed are shown to the left W ith a bit m ore work, I added three m ore stepper m otors to control the XY m otion and the extrusion. After a slight design m odification (because I didn? t want to pay $15 for longer screws), I fabricated the XY gantry, the part that carries the nozzle To com plete the m otion m echanism s, I added the CoreXY belts All of the m echanism s m oved properly.

FDM ax has reached a m ilestone recently since its m otion features have m ostly been com pleted, and because of m y im proved process, it happened in a fraction of the tim e it took for the first m odel. The next step is the electronics panel, which will house the power regulator and m ainboard. That will be followed by flashing the firm ware to the board, and after som e m ore testing, I presum e, FDM ax will be fully operational. M y goal is to have the m ajority of the work done by the end of M ay.

Overall, this 3D printer project has been successful. The project offered a great opportunity to practice innovation in a com plex m achine, and personally, it taught m e a valuable lesson about the role of design in the m aking process. 3D printing has been a fun hobby and inspiration for m e, and I?m glad that I?ve been able to m ake a thoughtful contribution The project still continues, and if all goes right, it will be an incredible vision com e to life.