Rather than bore the internet with descriptions of what I’ve been up to in dental school, I’ll focus on the interesting aspects of my most recent endeavors. A few weeks ago I took the final (third-level, extra class) amateur radio license exam. It’s a bunch of technical questions about radio circuitry, antenna theory, and other random stuff. You can see what I mean by taking an online practice test! I passed [whew!] and applied for a new call sign (extra class operators can have shorter call signs). The FCC gave me a VD. AJ4VD that is! Yes, my old call sign KJ4LDF has gone out the window as I am now AJ4VD! In morse code, that’s [.- .--- ....- ...- -..]. Speaking of code, I made my first contact in Morse code from my apartment! Let me set the scene for you…

This is the radio I’m using. It’s a Ten-Tec Century 21 HF CW transceiver which puts out ~30W.

I’m using a super-cheap but surprisingly functional homebrew base-loaded vertical antenna! The main vertical element is quarter-inch copper pipe from Home Depot (a couple bucks) cut with 1” to spare from my 10ft ceiling. Therefore, it’s a less-than quarter-wave vertical element, requiring a tuning coil (variable inductor at the base)…

Here you can start to see the tuning coils. Briefly, I scraped a deep gash in the copper pipe such that a big glob of solder would adhere to it, and stuck a wire (yellow, coated) into that solder so it’s a good connection to the pipe. I then started wrapping the wire around a few toilet paper rolls [it's all I could find at the time!] adding tap points (regions of exposed wire) every other turn. This functioned somewhat, but didn’t allow for fine-tuning (pun intended). I therefore scrapped the bottom half of the cardboard cylinder/coil and constructed a slightly more elegant solution…

That’s an Olvaltine container. Yeah, I know, “More chocolaty Olvaltine please!” I used a rotary tool to scrape some measured/templated gashes on each side to give the wire (picture frame hanging wire from Target, 50′ for $1.99) something to rest in. It turned out not to be enough, so I hot-glued the wire into the holes. This gives me a lot of exposed wire space to allow me to “tap” the coil wherever I want. By modifying where I clip onto the coil, I modify the length of wire in the coil that’s used, therefore modifying the inductance of the coil, allowing for some tuning capabilities. Although it has a narrow tuning range, using the current setup I’m able to get my SWR down to 1:1 on 40m (nice!).

I made a couple of contacts since I got the rig last night. First was K4KOR in central TN, who was calling CQ. I replied (slowly), and he came back to me (blazing fast Morse code). I was unable to copy ANYTHING he said (I’m not that good of an auditory decoder yet!) I’m sure he’s incredibly nice and it wasn’t intentional, but I had to give up the QSO. I know he copied my call, and I copied his, but I didn’t copy ANYTHING else he said. Does that count as my first contact? This morning I fired up the rig at 9:15 and heard W4HAY calling CQ from Northeast TN. I replied, stating that I’m new to CW so go slowly, and he was AMAZINGLY nice at sending me code at a snails pace. I was able to copy 90% of what he said, and will consider him my first solid contact! How cool is that?

And, as a closing note, Misia performing “Everything” (my favorite song) in Seoul, Korea:

I realized I never posted video of my finished prime number generator, so here it is. Full details are described on the project page. In brief, the 2-digit display on the left is the last two digits (in base-10, decimal) of a number currently being tested for primeness. This number is also displayed on the bottom red bar above the yellow lights (in base-2, binary). Once proven to be prime (by attempting to divide it by every number between 2 and its square root, every 1000th attempted number shown in yellow lights in binary), it’s loaded onto the top row of red lights (binary) and on the character LCD. N represents the Nth prime, with V representing its value. Half way through the video, the display says that the 16,595,044′th prime (N) equals 306,692,621 (V). Don’t believe it? Check my work.

After drawing this schematic in Inkscape I realized how useful such a design is for a general-purpose prototyping board. I mean, all 6 outputs control LEDs, with pin 13 controlling a LED and a speaker. All 5 inputs are used, taking in a combination of switches, buttons, and a potentiometer. Before you yell at me, yes, I understand that it is a waste to control LEDs directly by output pins and I get that. You could greatly expand the number of LEDs while reducing the number of output pins used by adding in a $2 shift register but since I don’t need it for my project, I’m not adding it! So there! I didn’t include the values of the resister because it depends on your input potential and current. Figure it out yourself. You could be like an electrical engineering student and perform mathematical calculations to determine the proper degree of resistance, or you could be like me and reach into a bag of random resisters and start testing them until you find one that makes the LEDs glow without getting too hot. Qualitative analysis. Nice.

UPDATE: I decided to also post a schematic more representative of the switches I used. Although the above schematic diagram is accurate, each of the switches are actually 2-way switches. Their function is not intended to be on/off (enable/disable), but rather switching between two modes (ie: using the know to adjust frequency or speed). I wanted lighted verification of the state of the pin in either case, rather than a single LED (where on means one thing, off means another thing). More specifically I wanted one LED on when the switch was one way, and a different LED on when the switch was the other way. I accomplished this with a minimum of parts and of ultimate simplicity using the following scheme. Briefly, power is supplied to the switch. If the switch is to the right, the right LED lights up, and the microchip (input pin) gets some of the power and a “high” sate is detected. If the switch is to the left, the left LED lights up, and the microchip (input pin) doesn’t get voltage so its state is “low”. To prevent a floating state (where the pin is connected to nothing, causing unpredictable behavior which makes the pin randomly and sporadically switch between high and low for apparently no reason) the input pin is grounded by a high-impedance resistor. The resister between the 5V and the switch is just to prevent the LEDs from getting too much power. Pretty simple and sweet. The final effect looks awesome, and doesn’t take up any output pins.

note: the “on” and “off” should probably be written as “high” and “low” and simply refer to the presence or absence of significant positive potential being applied to the input pin

As a motion of full disclosure (motivated by my persistent desire to reliably document my life), I present to you my dental application essays! Note that I was accepted into dental school (yay!) at the University of F|0R1D4. Why do I write it like F|0R1D4 instead of spelling it normally? Because would rather not have google associate me (and this essay) with the specific university I will be attending.

Initial essay:

Of all the knowledge and skills that I gained while pursuing my Master of Science degree, it is the experience I gained while conducting independent research that will contribute most to my career as a dentist. A future in dentistry will allow me to utilize my unique combination of talents to help people in need, and I know that the unique combination of my talents, academic potential, social skills, personal motivation, and my desire to serve others will allow me to excel in this profession. However, in order to fully appreciate the unique qualities I possess which set me apart from many other students my age who are pursuing similar goals, it is first necessary to understand how I reached the point where I am today. Although I skipped my senior year of high school to begin college a year early, I found the transition to be an exciting one. Tuition assistance from F|0R1D4’s Bright Futures scholarship program gave me the flexibility to take classes other than those required by my major, without having to endure their financial impact. I was fortunate enough to have taken many courses in subjects I was interested in (including programming classes and math classes through Calculus III), expanding the field of knowledge I possess today. While pursuing my Bachelor of Science in Tennessee, I became very active in the biology and chemistry departments of my university. The more I learned about the intricacies of living systems, the more I became amazed by their complexity. I served as the elected representative for the junior class in Union University’s chapter of the Student Affiliation of the American Chemical Society (SAACS) and I spent many days volunteering in community outreach programs sponsored by the department. However, it was the introduction into independent research that proved to be the most life-changing. While developing my senior biology research project, I became captivated by the process of scientific investigation. I discovered that I was able to combine logic and knowledge with creativity, mixing my new understanding of biology with previous computer and math skills to create truly novel experimental designs. My senior project, “An Improved Assay for Measuring the Effects of Acetylcholine, Caffeine, and Nicotine on the Heart Beat Rate of Larval Triops”, won the faculty-voted award for the best research project of the department in the spring of 2007. Although I intended to begin dental school in the fall of 2007, the admission departments had other plans for my future. Taking my initial rejection in good stride, but still strongly desiring to become a dentist, I decided to expand my knowledge of biology and develop whatever other skills I could by pursuing a graduate degree with the intention of re-applying to dental school. While pursuing a Master of Science in the field of Molecular Biology and Microbiology, I have gained more knowledge than I would ever have imagined. I also obtained valuable experience developing personal relationships in a professional environment, figuring out how to study at a graduate level, and polishing my fine motor skills by performing incredibly small and intricate surgical procedures on animals. Working under the guidance of Dr. Zixi Cheng, I am conducting cardiovascular research via multiple projects simultaneously. The most unique of which is the development of a method to measure the density of immunohistochemically-labeled neurites in thick heart tissue (something that has been previously considered to be impossible) with the goal of assessing the effects of diabetes on the heart and working toward effective treatments. Such research requires me to work with microdissection tools under a surgical microscope, performing intricate and precise procedures on the hearts of living mice. This has enabled me to develop a high degree of eye-hand coordination, familiarity working with microsurgical instruments under high magnification, and a level of fine motor skills that are becoming near those of a seasoned surgeon. It has been my dream for many years to become a dentist, and following acceptance into dental school I will work hard to become a prominent figure in the community and a great example for all those who have similar dreams. My undergraduate and graduate school experiences have both equipped and energized me to pursue a career in dentistry, and the skills I have acquired along the way have prepared me well to pursue my dream of becoming a dentist.

Supplemental essay:

It is often said that a person is the sum of their experiences. To understand more about who I am as a person, why I have the personality that I do, and even why I am applying for dental school, one can look at the experiences I had that shaped me into what I am today. Growing up as a child in a family of dentists I had the unique opportunity to observe all aspects of the profession. Not only was I exposed to discussions of dental procedures and observed first-hand doctor/patient interactions, but I also had the chance to see the intricacies of how a successful practice was run, from maintaining and managing the office environment to developing strong relationships between the dentists and staff members. The importance of education was always emphasized in my family, and as a result I have a strong desire to work hard to make my own academic career a successful one. One of the most interesting features of my personality is that I have a persistent, intense desire to excel at whatever I work on. This inclines me to be drawn toward hobbies, projects, and perhaps even careers that are notoriously difficult, but that have the ability to be mastered. In my early teen years, I enjoyed using computers, but my desire to master the subject pushed me to learn as much about them as possible. After becoming fluent in 11 programming languages, I was able to get a job writing software for a small engineering company that developed GPS tracking devices for fleet vehicles. When I began college, I enjoyed learning math, and my desire to excel pushed me to take (and master) extra courses in the mathematics (through Calculus III). When I began working on a senior biology project as an undergraduate at Union University, my desire to do my best led me to develop something far beyond the requirements of the project, eventually resulting in novel research data that was voted (by faculty) the best of all students. My strengths are my passions, and I become passionate at whatever I work on. I have been studying molecular biology and microbiology for the last two years in graduate school. When I started the Master’s program, I had little knowledge or interest in molecular biology, and knew even less about the intrinsic cardiac nervous system (the subject matter of my thesis). However, after I was given the opportunity to learn the material in the classroom and use my hands to practice delicate operations in the laboratory, my skills increased, my interest heightened, and I became passionate about what I was learning and working on. It is my desire to excel at my work that makes me succeed at whatever I begin to work on, and I look forward to beginning (and eventually succeeding at) my dental career! Obviously, there is much more to dentistry than academics alone. After spending so many years in a college environment, it is easy to become detached from the rest of the world and assume that everybody else sees the world the same way that you do. One of my lifelong desires is to always be able to communicate and relate with the people I work with, and never lose perspective as to the needs of the people around me. I feel fortunate to have had the opportunity to be exposed to different cultures throughout my life. Surprisingly, a great source of experience in communicating with people from every conceivable background was a job I held for approximately two years as a waiter in a restaurant in the F|0R1D4 Mall in Orlando. Although it was not glamorous work, it helped me perfect my communication skills and learn how to relate with and try to please many different types of people from all walks of life. In 2002, I visited China for a few weeks while my family adopted my younger sister Hannah. It was an unforgettable experience that opened my eyes to the needs of the world. I saw first hand that, even near some of the most successful cities of China (Kunming and Guangzhou), absolute poverty prevented many people from obtaining even the most basic medical services. It is easy to look at America and assess its needs, forgetting that there is an entire world in need. My father’s parents (a dentist and a dental hygienist) taught me the importance of dental charity work, both locally and internationally. As a child I would listen to their stories about traveling to Guatemala and Peru helping villagers with their dental needs, working on people who had no ability to pay them back in any way. I always hoped that one day I could become a dentist too, so that I could help people in a similar way. However, one does not have to travel the world to help those in need. My wife’s childhood story is completely different than my own, and getting to know her has really opened my eyes to the needs of the community. Growing up as the daughter of illegal Mexican immigrant with an African-American mother in poor health, having almost nothing, with barely enough money for food (let alone medical and dental services), my wife has opened my eyes to see the world from a completely different perspective. She had never been to the dentist before I met her (a concept that was shocking to my family of dentists!). Getting to know her has opened my eyes as to the way that much of society views many issues, including the field of dentistry. It is a service that is both a need and a luxury – something that must be made more available to all people, but in a way that does not diminish the quality of the work. I know that there is no perfect solution for how to treat all of the people who need dental work but cannot afford it, but that does not mean that we (dentists) can not try to improve the situation. I feel that there is more to being a successful dentist than simply being fiscally productive. I believe that dentists have the ability to make a true impact on the world, because they offer such a valuable service that so many people need. I have no doubt that I possess the skills, desire, and motivation to become a successful dentist, and I look forward attending dental school at the University of F|0R1D4 to help me reach my goal of becoming one. As a dentist, I will strive to continue my family’s legacy of providing quality dental work to those who can afford it, while also offering charity dental services both locally and internationally for those who cannot.

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