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The Need for Climate-Friendly Refrigerants & Technologies

Posted on Apr 28, 2017 in Blog

1,1,1,2-tetrafluoroethane/R-134aEver since the development of vapor-compression refrigeration in the early 20th century, chemists have constantly been tinkering to find more efficient and cost-effective refrigerants. Until the late 1980’s, the most common refrigerants were chlorofluorocarbons, or CFCs. CFCs are organic compounds made up of carbon, chlorine, and fluorine (derived from methane, ethane, and propane), and are best known by their DuPont brand name: Freon. However, CFCs were found to be contributing to the depletion of the ozone layer, and in 1987 the multi-national Montreal Protocol on Substances that Deplete the Ozone Layer was agreed upon, which involved phasing out CFCs as refrigerants.

As CFCs were phased out throughout the 1990s, their primary replacements as refrigerant were hydrofluorocarbons, or HFCs. HFCs contain hydrogen atoms instead of the chlorine atoms found in CFCs. One of the most prolific HFCs, 1,1,1,2-tetrafluoroethane (known more commonly as R-134a), is used by Powers Scientific in all our refrigerated chambers. HFCs are an upgrade over CFCs in that they are much less destructive to the ozone layer. However, they are not a perfect solution. As concerns about climate change continue to grow, HFCs have come under scrutiny for their global warming potential (GWP). As the levels of HFCs in the atmosphere continue to increase, so does the climate risk. To keep this emergent environmental danger in check, world leaders met in Rwanda last October to make a deal to lower HFC usage. They agreed to lower the worldwide usage of HFCs by 80-85% by 2047.

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Minimizing Water Loss in Plants Through Genetics

Posted on Mar 30, 2017 in Blog

cactusPhotosynthesis, the driver for all plant life on earth, requires three things: water, carbon dioxide and sunlight. Carbon dioxide and sunlight are in plentiful supply across the earth, but water can be much more difficult to come by in certain areas. Of course, a scarce water supply does not mean that plants can’t survive – many plant species can do just fine in very dry climates. One of the key principles for plants to grow in these areas is to conserve as much water as possible. Most plants bring carbon dioxide into their system by opening their stomata (pores, usually in the of leaves or stems, that control oxygen and carbon dioxide exchange) during the day to fuel photosynthesis. However, opening the stomata during the day is grossly water inefficient. Evaporation from the heat of the sun’s rays leads to massive amounts of water loss.

To combat the evaporative losses, the best thing to do would be to keep the stomata closed during the day and and then open them for carbon dioxide intake at night when the temperate is lower. However, the main hurdle to this approach is that the entire point of bringing carbon dioxide into the plant is so that it can be used in photosynthesis. Since photosynthesis requires light, bringing in carbon dioxide at night would be useless for most plants. However, some plants have figured out a way around this problem. The process is referred to as crassulacean acid metabolism, or CAM, which is named for the family of plants in which it was first studied, i.e., the Crassulaceae plant family. (note that CAM stands for how Crassulaceae metabolize acid, NOT how “crassulacean acid” is metabolized.)

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Trying to Turn Back the Aging Clock

Posted on Mar 2, 2017 in Blog

Epigenetic nucleosome structureDNA is fundamental for carrying genetic instructions for the growth and development of all known living organisms. However, DNA is not the sole tool for implementing genetic instructions. Epigenetic marks are cellular features that are made up of various amino acid and protein groups that can modify proteins within a cell. These epigenetic marks are not governed by the genetic code, but are nevertheless capable of influencing the way genes are expressed. The buildup of these epigenetic marks in our cells has been suspected as a driving factor of the aging process.

What if there was a way to strip these epigenetic marks from cells? Would that allow us to effectively reset the aging clock? A recent article in Science News talks about how researchers are working on answering that question through experiments on genetically engineered mice. The research took mice that had been genetically engineered to express two important characteristics. The first trait necessary was to show the same premature aging patterns as mice used as models to study Hutchinson Gilford Progeria Syndrome. The second required trait was the ability for the mice to produce four specific proteins when given an externally-controllable trigger. These proteins – Oct4, Sox2, Klf4, and c-Myc – or OSKM for short, are also known as “Yamanaka factors” after the Nobel prize-winning Shinya Yamanaka, who discovered that these proteins could turn adult cells into induced pluripotent stem cells (iPS cells).

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Engineering Plants to Survive Salt

Posted on Jan 27, 2017 in Blog

saltAccording to the United Nations, over 12 million hectares of arable land are lost to drought and desertification every year. 12 million hectares is approximately the land area of Louisiana, and represents the potential loss of up to 20 million tons of grain that could have been grown in these areas. Salinity is also a huge problem for agriculture: nearly 25% of the irrigated land in the world now is now plagued by overly salty soil. These salt-filled soils are caused by factors like poor irrigation practices and saltwater intrusion from rising sea levels.

Most plant species, including essentially all farmed crops, are referred to as glycophytes. Glycophytes are not salt-tolerant and are damaged easily in high salinity environments. High salt concentrations in these species disrupt vital internal processes, eventually leading to the death of the plant. Their only defenses against salt are physical and chemical barriers in the root systems, but these features can only keep out low levels of salt. However, a few plant species (perhaps only 2% or so), are considered halophytes. Halophytes (literally: “salt plants”) are plants that can survive in high-salinity environments. Halophytes include species such as mangroves, quinoa, and Arabidopsis thaliana, a plant commonly used in genetic research. For comparison, crop plants like beans and rice can tolerate around 1-3 grams of salt per liter of water, while Salicornia bigelovii (dwarf glasswort, a halophyte) can flourish in water with salt concentrations as high as 70 grams per liter!

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Possible Dangers of Cool White LED Lights in Animal Research

Posted on Dec 22, 2016 in Blog

sun UV imageThe light of the sun fuels all life on Earth. Of course, with the massive amount of electromagnetic energy the sun delivers to the planet, there are going to be some dangerous side effects. For example, the toxic effects of ultraviolet (UV) light are well established. Short-wave (i.e., UVB and UVC) radiation in particular is known to cause damage to DNA, which leads to skin cancer in humans as well as having lethal effects on other animals and microorganisms. However, the potentially harmful effects of visible spectrum light on organisms are not as extensively studied. It is possible that certain wavelengths of visible light can be more harmful than UV light to some animals, insects in particular. It is even possible that for insects, short-wave visible light in the blue part of the spectrum could be more harmful than UV light.

A 2014 study looked at the effects of different wavelengths of visible light on the development of Drosophila melanogaster and other insects. The researchers found that blue light from LEDs (with wavelengths in the range of 440-467 nm) caused up to a 100% mortality rate for the flies before their adult emergence. The mortality rates when exposed to blue light were significantly higher compared to when the flies where exposed to LEDs delivering light at longer wavelengths on the visible spectrum. Additionally, the blue-light mortality rates were even higher than those from exposure to UV light! This was the first study to show that irradiation with visible light can be lethal to animals as complex as insects.

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