Monday, October 20, 2014

2014 Nobel Prizes Awarded!

The 2014 Nobel Prizes were recently awarded.  Annual Nobel Prizes are awarded for achievement in Physics, Chemistry, Physiology/Medicine, Economics, Literature, and Peace.

The Nobel Prize in Physics was awarded jointly to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura "for the invention of efficient blue light-emitting diodes (LEDs) which has enabled bright and energy-saving white light sources".  While LEDs have existed for half a century, the creation of the blue-emitting LED when combined with either existing red and green LEDs or phosphor excitement allows the production of bright white light that is far brighter and more efficient than previous lighting technology. The development of blue LEDs was a long process, and the laureates’ updated work was presented through a series of publications over the course of 5-10 years. Both a general and a more scientific overview of the technology and its creation can be found at the Nobel Prize website. 
The Nobel Prize in Chemistry was given to Eric Betzig, Stefan W. Hell and William E. Moerner for improving optical microscopy beyond the previously believed limit to the nanometer scale.  This feat was achieved by two independent methods, stimulated emission depletion (STED) microscopy by Stefan W. Hall, and single-electron microscopy by Eric Betzig and William E Moerner. STED creates high-resolution images by detecting fluorescent light with a nanoscale-width laser as all surrounding area is quenched.  Single-electron microscopy works differently, by weakly activating fluorescence randomly throughout the sample, repeating several times and then combining the images to obtain a high-resolution final processed image.  These two methods allow fluorescent visualization of structures such as viruses and individual proteins that were previously too small to resolve.  The physics behind these breakthroughs will surely revolutionize biological microscopy.

The Nobel Prize in Medicine was awarded 50% to John O’Keefe and 25% each to May-Britt Moser and Edvard I. Moser for discovering how our brain is able to orient ourselves and properly position ourselves within the environment.  O’Keefe identified hippocampal “place cells” that provide positional and spacial memory information while the Mosers discovered “grid cells” within the etorhinal cortex that offer directional coordination.  Each of these cells were found to be activated in particular locations and sequences of their respective brain regions and have important roles in understanding spacial memory and navigation.

Since this is a science blog I will not delve deeply into the other prizes, but just to summarize: the Nobel Prize for Economics was awarded to Jean Tirole for describing the framework for proper regulation of financial institutions, the Nobel Prize for Literature went to French author Patrick Modiano "for the art of memory with which he has evoked the most ungraspable human destinies and uncovered the life-world of the occupation", and the Nobel Prize for Peace was given to Kailash Satyarthi and Malala Yousafzai for fighting for children’s rights.  Satyarthi protested against child labor while Yousafzai risked her own life to fight for girls’ right to an education.

Tuesday, August 5, 2014

The (Radioactive) Decay of Western Civilization: Nuclear Physics and the Safety of Nuclear Power

          Nuclear physics and radioactive decay are probably among the most misunderstood scientific topics by the general public.  People have been terrified of nuclear energy since the creation of the nuclear bomb, fear which has only been enhanced both by legitimate disasters such as Chernobyl and the Fukishima Power Plant along with a 60+ year history of films that exaggerate the dangers and misrepresent the science.  Nuclear power plants have a better safety record than the fossil fuel plants that most of our energy currently comes from, while also being more environmentally-friendly.  Many scientists believe that worldwide energy problems could be improved by nuclear power, without the need for investing in newer less efficient technologies, if only they would be accepted by the public.  This post will explain the science behind nuclear power, atomic bombs and radioactive decay, including how they are so often misunderstood by society and the media.

Radioactive Decay
          Radioactive decay is the random breakdown of an atom with an unstable nucleus into a more stable form, releasing energy in the process.  Every radioactive substance has a predictable rate of decay, known as a half life.  The half-life of a radioactive substance is the time that it will take for half of its atoms to decay.  Radioactive decay releases energy, and it is the released energy that is known as radiation.  There are three major types of radiation released from decay: alpha decay, beta decay and gamma decay.  Alpha decay releases an alpha particle, which is essentially a Helium nucleus containing 2 protons and 2 neutrons.  It cannot penetrate materials very deep but is extremely damaging.  Beta decay releases an electron and in contrast to alpha decay, it has greater penetrance but is less harmful.  Gamma decay expels a high-energy photon, which is extremely penetrating while also able to cause DNA damage.  Radioactive decay occurs in all elements of atomic number (number of protons) 83 (bismuth) or greater.  Additionally, radioactive isotopes (varying number of neutrons) naturally exist for many elements under atomic number 83 at a specified ratio in nature.  By utilizing knowledge of the known ratio of these isotopes in nature and their half-life, they are useful for a multitude of processes including archaeological dating, medical imaging, and tracing of biological processes.

Nuclear Fission
          Nuclear fission is very often confused with radioactive decay.  While both involve the release of energy due to nuclear degradation, the two processes are unrelated.  Nuclear fission is usually instigated by bombardment with neutrons and results in the release of two large fragments of somewhat unpredictable size along with neutrons and massive amounts of energy. Unlike radioactive decay which is a controlled spontaneous process occurring at regular intervals that releases defined smaller particles (alpha, beta), nuclear fission only occurs spontaneously at extremely low rates in certain heavy elements (can theoretically occur in elements above atomic number 92, but only realistically observed above atomic number 231), and is typically induced through man-made reactions in only a select group of isotopes.  Isotopes that are able to undergo fission upon bombardment with a high energy neutron (even at low probability) are fissionable, while isotopes that can easily fission with lower-energy neutrons are fissile.  Nuclear fuel for energy reactors or bombs typically utilizes Uranium (U)-235, U-233, Plutonium (Pu)-239 and Pu-241.  These nuclides are all fissile isotopes that are capable of sustaining a chain reaction of neutron release and capture, are relatively abundant and are radioactively stable.

Wednesday, July 16, 2014

The Importance of Fixing Science Education

I have a guest post that I wrote for Scouse Science Alliance, an excellent blog run by PhD students at the University of Liverpool in the UK.

My post talks about the future of science education, primarily in the USA but also its impact internationally.  Improving science education and literacy is something I care greatly about (hence this blog), so please check it out here.

While you are over there, check out the rest of their blog, they have some great features aimed at a non-academic audience including opinion pieces, featured scientist of the month and highlighted recent scientific discoveries of interest.

Wednesday, April 30, 2014

Don’t STAP Believing: When Scientific Breathroughs Really Are Too Good To Be True

    I was recently asked to write a guest post for The Biology Blog about the recent STAP stem cell controversy.  The Biology Blog has over 3700 likes on Facebook and over 6600 followers on Twitter.  It features commentary on a regular basis about recent research papers, general scientific discussion and more.  I recommend checking it out!

    To learn about the saga of the recent publications on Stimulus-Triggered Acquisition of Pluripotency (STAP) cells and my personal view on the situation, check out my post here.

Wednesday, January 1, 2014

Children of the Corn (Syrup): Is High Fructose Corn Syrup Actually Worse Than Sugar?

          In the United States, high fructose corn syrup (HFCS) is often used as a sweetener in place of cane sugar in both food and beverages.  Many consumers are concerned about the relative health effects of HFCS compared to sugar, and the increased consumption of HFCS in western nations such as the US is associated with a greater prevalence of poor health outcomes such as type II diabetes.  This concern has caused a recent campaign to replace HFCS with cane sugar in popular foods and beverages, such as the increase in popularity of HFCS-free Mexican Coke.  As with Genetically Modified Organisms, health fears over HFCS have created an irrational fervor among the general public, even among educated individuals.  I have therefore attempted to provide a (mostly) unbiased, rational summary of existing data on the subject to promote better-educated personal decisions on dietary choices.

General Background on HFCS
The chemical process for creating HFCS was first invented in 1957 and was later optimized for industrial scale production by Dr. Yoshiyuki Takasaki in the late 1960s-1970.  HFCS is now the leading sweetener (and #1 source of calories) in the US due to many factors, including tariffs on foreign sugar, subsidies to corn farmers, and industrial benefits of its liquid state.  HFCS is produced by isolating glucose-rich corn syrup and  enzymatically converting some of the glucose into fructose. Two primary types of HFCS exist: HFCS-42 (42% fructose/53% glucose) and HFCS-55 (55% fructose/42% glucose).  HFCS-55 is typically used in soft drinks and other beverages, while HFCS-42 is often used in processed foods and baked goods.  It is important to note that despite the name, HFCS in both forms maintains close to a 50% ratio of fructose, similar to that in sucrose (with glucose) and honey (with dextrose).  Fructose and glucose exist independently together in solution as HFCS while sucrose contains covalently linked glucose and fructose molecules that are only separated upon metabolism.

Research Studies
          One of the most cited studies suggesting a relationship between HFCS consumption and negative health outcomes was published by Bray et al in 2004, which stated that “the increased use of HFCS in the United States mirrors the rapid increase in obesity”.  The study also claimed that fructose is metabolized differently than glucose, leading to increased fat production in the liver and reduced insulin release.  Additionally, reduced insulin levels decrease secretion of leptin (in agreement with another paper), which induces satiety and restricts hunger.  In strong criticism of these conclusions was a sternly worded report debunking the association between obesity and HFCS.  The report argued that increased overall caloric intake is more likely the cause of increasing obesity rates, evidenced by the fact that HFCS use in the US has actually remained stable over the past 15 years despite ever increasing obesity rates, while the ratio of HFCS consumption does not actually correlate with obesity worldwide (Figure 1).

(John White, Am J Clin Nutr 2008)