First World Health Problems

Catalyst VOlume 10

I am a first generation American, as both of my parents immigrated here from Myanmar, a third world country. There had been no occurrence of any Inflammatory Bowel Disease (IBD) in my family, yet I was diagnosed with Ulcerative Colitis at the beginning of my sophomore year of high school. Since IBD is known to be caused by a mix of genetic and environmental factors,^1,2 what specifically triggered me to develop Ulcerative Colitis? Was it the food in America, the air I was exposed to, a combination of the two, or neither of them at all? Did the “environment” of the first world in the United States cause me to develop Ulcerative Colitis?

IBD is a chronic autoimmune disease, characterized by persistent inflammation of the digestive tract and classified into two separate categories: Ulcerative Colitis and Crohn’s Disease.³ Currently, there is no known cure for IBD, as its pathogenesis (i.e. the manner in which it develops) is not fully understood.¹ Interestingly, the incidence of IBD has increased dramatically over the past century.¹ A systematic review by Molodecky et al. showed that the incidence rate of IBD was significantly higher in Western nations. This may be due to better diagnostic techniques or the growth of environmental factors that promote its development. This could also suggest that there may be certain stimuli in first world countries that can trigger pathogenesis in individuals with a genetic predisposition to IBD.

Environmental factors that are believed to affect IBD include smoking, diet, geographic location, social status, stress, and microbes.¹ Smoking has had varying effects on the development of IBD depending on the form; smoking is a key risk factor for Crohn’s Disease, while non-smokers and ex-smokers are usually diagnosed with Ulcerative Colitis.⁴ There have not been many studies investigating the causal relationship between diet and IBD due to the diversity in diet composition.¹ However, since IBD affects the digestive system, diet has long been thought to have some impact on the pathogenesis of the disease.¹ In first world countries, there is access to a larger variety of food, which may impact the prevalence of IBD. People susceptible to the disease in developing countries may have a smaller chance of being exposed to “trigger” foods. In addition, IBD has been found in higher rates in urban areas versus rural areas.^1,4,5 This makes sense, as cities have a multitude of potential disease-inducing environmental factors including pollution, poor sanitation, and microbial exposure. Higher socioeconomic status has also been linked to higher rates of IBD.⁴ This may be partly due to the sedentary nature of white collar work, which has also been linked to increased rates of IBD.¹ Stress used to be viewed as a possible factor in the pathogenesis of IBD, but recent evidence has indicated that it only exacerbates the disease.³ Recent research has focused on the microorganisms in the gut, called gut flora, as they seem to have a vital role in the instigation of IBD.¹ In animal models, it has even been observed that pathogenesis of IBD is not possible in a germ-free environment.¹ The idea of the importance of microorganisms in human health is also linked to the Hygiene Hypothesis.

The Hygiene Hypothesis states that the lack of infections in western countries is the reason for an increasing amount of autoimmune and allergic diseases.⁶ The idea behind the theory is that some infectious agents guard against a wide variety of immune-related disorders.⁶ Animal models and clinical trials have provided some evidence backing the Hygiene Hypothesis, but it is hard to causally attribute the pathogenesis of autoimmune and allergic diseases to a decrease in infections, since first world countries have very different environmental factors than third world countries.⁶

The increasing incidence of IBD in developed countries is not yet fully understood, but recent research points towards a complex combination of environmental and genetic factors. The rise of autoimmune disease diagnoses may also be attributed to better medical equipment and facilities and the tendency of people in more developed countries to regularly get checked by a doctor. There are many difficulties in researching the pathogenesis of IBD including isolating certain environmental factors and obtaining tissue and data from third world countries. However, there is much promising research and it might not be long until we discover a cure for IBD.

References

1. Danese, S. et al. Autoimm Rev 2004, 3.5, 394-400.
2. Podolsky, Daniel K. N Engl J Med 2002,  347.6, 417-29.
3. Mayo Clinic. "Inflammatory Bowel Disease (IBD)." http://www.mayoclinic.org/diseases-conditions/inflammatory-bowel-disease/basics/definition/con-20034908 (accessed Sep. 30, 2016).
4. CDC. "Epidemiology of the IBD." https://www.cdc.gov/ibd/ibd-epidemiology.htm (accessed Oct.17, 2016).
5. Molodecky, N. et al. Gastroenterol 2012, 142.1, n. pag.
6. Okada, H. et. al. Clin Exp Immuno 2010, 160, 1–9.

Fire the Lasers

Catalyst Volume 10

Imagine a giant solar harvester flying in geosynchronous orbit, which using solar energy, beams radiation to a single point 36, 000 km away. It would look like a space weapon straight out of Star Wars. Surprisingly, this concept might be the next so-called “moonshot” project that humanity needs to move forward. In space-based solar power generation, a solar harvester in space like the one discussed above would generate DC current from solar radiation using photovoltaic cells, and then convert it into microwaves. These microwaves would then be beamed to a rectifying antenna (or a rectenna) on the ground, which would convert them back into direct current (DC). Finally, a converter would change the DC energy to AC to be supplied into the grid.¹

With ever-increasing global energy consumption and rising concerns of climate change due to the burning of fossil fuels, there has been increasing interest in alternative energy sources. Although renewable energy technology is improving every year, its current energy capacity is not enough to obviate the need for fossil fuels. Currently, wind and solar sources have capacity factors (a ratio of an energy source’s actual output over a period of time to its potential output) of around 34 and 26 percent, respectively. In comparison, nuclear and coal sources have capacity factors of 90 and 70 percent, respectively.² Generation of energy using space solar power satellites (SSPSs) could pave the path humanity needs to move towards a cleaner future. Unlike traditional solar power, which relies on favorable weather conditions, SSPSs would allow continuous, green energy generation.

Although space-based solar power (SBSP) might sound pioneering, scientists have been flirting with the idea since Dr. Peter Glaser introduced the concept in 1968. Essentially, SBSP systems can be characterized by three elements: a large solar collector in geostationary orbit fitted with reflective mirrors, wireless transmission via microwave or laser, and a receiving station on Earth armed with rectennas.³ Such an implementation would require complete proficiency in reliable space transportation, efficient power generation and capture, practical wireless transmission of power, economical satellite design, and precise satellite-antenna calibration systems. Collectively, these goals might seem insurmountable, but taken separately, they are actually feasible. Using the principles of optics, scientists are optimizing space station design to maximize energy collection.⁴ There have been advancements in rectennas that allow the capture of even weak, ambient microwaves.⁵ With the pace of advancement speeding up every year, it’s easy to feel like the future of renewable energy is rapidly approaching. However, these advancements will be limited to literature if there are no global movements to utilize SBSP.

Japan Aerospace Exploration Agency (JAXA) has taken the lead in translating SBSP from the page to the launch pad. Due to its lack of fossil fuel resources and the 2011 incident at the Fukushima Daiichi nuclear plant, Japan, in desperate need of alternative energy sources, has proposed a 25-year technological roadmap to the development of a one-gigawatt SSPS station. To accomplish this incredible feat, Japan plans on deploying a 10,000 metric ton solar collector that would reside in geostationary orbit around Earth.⁶ Surprisingly, the difficult aspect is not building and launching the giant solar collector; it’s the technical challenge of transmitting the energy back to earth both accurately and efficiently. This is where JAXA has focused its research.

Historically, wireless power transmission has been accomplished via laser or microwave transmissions. Laser and microwave radiation are similar in many ways, but when it comes down to which one to use for SBSP, microwaves are a clear winner. Microwaves have longer wavelengths (usually lying between five and ten centimeters) than those of lasers (which often are around one micrometer), and are thus better able to penetrate Earth’s atmosphere.⁷ Accordingly, JAXA has focused on optimizing powerful and accurate microwave generation. JAXA has developed kW-class high-power microwave power transmission using phased, synchronized, power-transmitting antenna panels. Due to current limitations on communication technologies, JAXA has also developed advanced retrodirective systems, which allow high-accuracy beam pointing.⁸ In 2015, JAXA was able to deliver 1.8 kilowatts accurately to a rectenna 55 meters away which, according to JAXA, is the first time that so much power has been transmitted with any appreciable precision . Although this may seem insignificant compared to the 36,000 km transmissions required for a satellite in geosynchronous orbit, this is huge achievement for mankind. It demonstrates that large scale wireless transmission is a realistic option to power electric cars, transmission towers, and even satellites. JAXA,continuing on its roadmap, plans to conduct the first microwave power transmission in space by 2018.

Although the challenges ahead for space based solar power generation are enormous in both economic and technical terms, the results could be revolutionary. In a manner similar to the introduction of coal and oil, practical SBSP systems would completely alter human civilization. With continuous green energy generation, SBSP systems could solve our energy conflicts and allow progression to next phase of civilization. If everything goes well, air pollution and oil spills may merely be bygones.

References

1. Sasaki, S. IEEE Spec. 2014, 51, 46-51.
2. EIA (U.S. Energy Information Administration). www.eia.gov/electricity/monthly (accessed     Oct. 29, 2016).
3. Wolfgang, S. Acta Astro. 2004, 55, 389-399.
4. Yang, Y. et al. Acta Astro. 2016, 121, 51-58.
5. Wang, R. et al. IEEE Trans. Micro. Theo. Tech. 2014, 62, 1080-1089.
6. Sasaki, S. Japan Demoes Wireless Power Transmission for Space-Based Solar Farms. IEEE Spectrum [Online], March 16, 2015. http://spectrum.ieee.org/ (accessed Oct. 29, 2016).
7. Summerer, L. et al. Concepts for wireless energy transmission via laser. Europeans Space Agency (ESA)-Advanced Concepts Team [Online], 2009. https://www.researchgate.net/profile/Leopold_Summerer/ (accessed Oct. 29, 2016).
8. Japan Space Exploration Agency. Research on Microwave Wireless Power Transmission Technology. http://www.ard.jaxa.jp/eng/research/ssps/hmi-mssps.html (accessed Oct. 29, 2016).