|Steamboat Geyser in Yellowstone. By Brocken Inaglory (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons|
Monday, 30 January 2017
In 1901, the world's tallest geyser was discovered by Dr Humphrey Haines on the North Island of New Zealand. He was following up reports of great clouds of steam, and found the Waimangu Geyser near Rotorua. It appeared after an enormous eruption of Mt. Tarawera in 1886. The Waimangu Geyser was the largest geyser in the world and erupted on a 36 hour cycle for four years, hurling black mud and rocks in the air. Waimangu is Maori for "black water." It stopped in 1904 when a landslide changed the local water table. Eruptions would typically reach 600 feet. Some superbursts are known to have reached 1,600 feet (10 times as high as Yellowstone's famous Old Faithful, and which would be higher than the Empire State Building.)
Geyser activity, like all hot spring activity, is caused by surface water gradually seeping down through the ground until it meets rock heated by magma. The geothermally heated water then rises back toward the surface by convection through porous and fractured rocks. Geysers differ from non-eruptive hot springs in their subterranean structure; many consist of a small vent at the surface connected to one or more narrow tubes that lead to underground reservoirs of water and pressure tight rock.
As the geyser fills, the water at the top of the column cools off, but because of the narrowness of the channel, convective cooling of the water in the reservoir is impossible. The cooler water above presses down on the hotter water beneath, not unlike the lid of a pressure cooker, allowing the water in the reservoir to become superheated, i.e. to remain liquid at temperatures well above the standard-pressure boiling point.
Ultimately, the temperatures near the bottom of the geyser rise to a point where boiling begins which forces steam bubbles to rise to the top of the column. As they burst through the geyser's vent, some water overflows or splashes out, reducing the weight of the column and thus the pressure on the water below. With this release of pressure, the superheated water flashes into steam, boiling violently throughout the column. The resulting froth of expanding steam and hot water then sprays out of the geyser vent.
A key requirement that enables a geyser to erupt is a material called geyserite found in rocks nearby the geyser. Geyserite—mostly silicon dioxide (SiO2), is dissolved from the rocks and gets deposited on the walls of the geyser's plumbing system and on the surface. The deposits make the channels carrying the water up to the surface pressure-tight. This allows the pressure to be carried all the way to the top and not be leaked out into the loose gravel or soil that are normally under the geyser fields.
Eventually the water remaining in the geyser cools back to below the boiling point and the eruption ends; heated groundwater begins seeping back into the reservoir, and the whole cycle begins again. The duration of eruptions and time between successive eruptions vary greatly from geyser to geyser; Strokkur in Iceland erupts for a few seconds every few minutes, while Grand Geyser in the United States erupts for up to 10 minutes every 8–12 hours.
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Monday, 23 January 2017
Medical implants like stents, catheters and tubing introduce risk for blood clotting and infection - a perpetual problem for many patients.
Colorado State University engineers offer a potential solution: A specially grown, "superhemophobic" titanium surface that's extremely repellent to blood. The material could form the basis for surgical implants with lower risk of rejection by the body.
|Titanium (mineral concentrate). Public Domain, https://commons.wikimedia.org/w/index.php?curid=323468|
It's an outside-the-box innovation achieved at the intersection of two disciplines: biomedical engineering and materials science. The work, recently published in Advanced Healthcare Materials, is a collaboration between the labs of Arun Kota, assistant professor of mechanical engineering and biomedical engineering; and Ketul Popat, associate professor in the same departments.
Kota, an expert in novel, "superomniphobic" materials that repel virtually any liquid, joined forces with Popat, an innovator in tissue engineering and bio-compatible materials. Starting with sheets of titanium, commonly used for medical devices, their labs grew chemically altered surfaces that act as perfect barriers between the titanium and blood. Their teams conducted experiments showing very low levels of platelet adhesion, a biological process that leads to blood clotting and eventual rejection of a foreign material.
A material "phobic" (repellent) to blood might seem counterintuitive, the researchers say, as often biomedical scientists use materials "philic" (with affinity) to blood to make them biologically compatible. "What we are doing is the exact opposite," Kota said. "We are taking a material that blood hates to come in contact with, in order to make it compatible with blood." The key innovation is that the surface is so repellent, that blood is tricked into believing there's virtually no foreign material there at all.
The undesirable interaction of blood with foreign materials is an ongoing problem in medical research, Popat said. Over time, stents can form clots, obstructions, and lead to heart attacks or embolisms. Often patients need blood-thinning medications for the rest of their lives - and the drugs aren't foolproof.
"The reason blood clots is because it finds cells in the blood to go to and attach," Popat said. "Normally, blood flows in vessels. If we can design materials where blood barely contacts the surface, there is virtually no chance of clotting, which is a coordinated set of events. Here, we're targeting the prevention of the first set of events."
The researchers analyzed variations of titanium surfaces, including different textures and chemistries, and they compared the extent of platelet adhesion and activation. Fluorinated nanotubes offered the best protection against clotting, and they plan to conduct follow-up experiments.
Growing a surface and testing it in the lab is only the beginning, the researchers say. They want to continue examining other clotting factors, and eventually, to test real medical devices.
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Tuesday, 17 January 2017
Life is a process that originated 3.5 billion years ago. It emerged when the basic components of the cells that we know today, in other words, inanimate chemical molecules, gradually joined, merged, assembled themselves and interacted. At a given moment they became alive, or what amounts to the same thing, they turned into autonomous systems. As the years passed they gradually evolved until achieving their current complexity and diversity. A piece of research by the UPV/EHU is working on the start of this trajectory by studying how the chemical molecules assembled themselves so that life could begin.
|A section of DNA. Zephyris at the English language Wikipedia [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons|
DNA, RNA, proteins, membranes, sugars, …cells are made up of all kinds of components. In biology, and in the studies dealing with the origin of life specifically, it is very common to focus on one of these molecules and put forward hypotheses on how life originated by analysing the specific mechanisms related to it. "Basically, these studies are looking for the 'molecule of life', in other words, they set out to establish which was the most important molecule in making this milestone happen," said Kepa Ruiz-Mirazo, researcher in the Biophysics Unit and of the UPV/EHU's Department of Logic and Philosophy of Science. However, bearing in mind that "life involves activity among a huge variety of molecules and components, a change of approach has been taking place in recent years and research that takes into account various molecules at the same time is gaining strength," he added.
Besides emerging in favour of this fresh approach, Ruiz-Mirazo's group, in collaboration with the University of Montpellier, through an internship of the UPV/EHU PhD student Sara Murillo-Sánchez, has been able to show that interaction exists between some molecules and others. "Our group has expertise in research into membranes that are created in prebiotic environments, in other words, in the study of the dynamics that fatty acids, the precursors of current lipids, may have had.
The Montpellier group for its part specialises in the synthesis of the first peptides. So when the knowledge of each group is put together, and when we experimentally blended the fatty acids and the amino acids, we could see that there was a strong synergy between them."
As they were able to see, the catalysis of the reaction took place when the fatty acids formed compartments. As they are in an aqueous medium, and due to the hydrophobic nature of lipids, they tend to join with each other and form closed compartments; in other words, they take on the function of a membrane; "at that time the membranes obviously weren't biological but chemical ones," explained Ruiz-Mirazo. In their experiments they were able to see that the conditions offered by these membranes are favourable for amino acids. "The Montpellier group had the prebiotic reactions of the formation of dipeptides very well characterised, so they were able to see that this reaction took place more efficiently in the presence of fatty acids," he added.
Besides demonstrating the synergy between fatty acids and amino acids, Ruiz-Mirazo believes it is very important to have conducted the study using basic chemical components, in other words, molecular precursors. "Life emerged out of these basic molecules; therefore, to study its origin we cannot start from the complex phospholipids that are found in today's membranes. We have demonstrated the formation of the first coming together and formation of chains on the basis of molecular precursors. Or to put it another way, we have demonstrated that it is possible to achieve diversity and complexity in biology by starting from chemistry."
In his studies, in addition to the experimental work, Ruiz-Mirazo is working in another two spheres so in the end he is studying the origin of life from three pillars or perspectives: "firstly, we have the experimental field; another is based on theoretical models and computational simulations, which we use to analyse the results obtained in the experiments, and the third is a little broader, because we are studying from the philosophical viewpoint what life is, the influence that the conception held about life exerts on the experimental field, since each conception leads you to carry out a specific type of experiment," he explained. "These three methodologies mutually feed each other: an idea that may emerge in the philosophical analysis leads you to carry out a new simulation, and the results of the simulations mark out the path for designing the experiments. Or the other way round. Most likely we will never manage to find the answer to how life began, but we are working on it: all of us living beings on Earth have the same origin and we want to know how it happened."
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Tuesday, 10 January 2017
Who doesn’t love fireworks at New Year? Yet whilst fireworks are undoubtedly a spectacle, they can also have a negative effect on the environment. Take a look at the graphic below, to discover some of the issues that they can cause.
|Source: Compound Interest|
So that’s the science, but what about the history? Who first invented the firework?
The earliest documentation of fireworks dates back to 7th century China (time of the Tang Dynasty), where they were invented. The fireworks were used to accompany many festivities. It is thus a part of the culture of China and had its origin there; eventually it spread to other cultures and societies.
The art and science of firework making has developed into an independent profession. In China, pyrotechnicians were respected for their knowledge of complex techniques in mounting firework displays. Chinese people originally believed that the fireworks could expel evil spirits and bring about luck and happiness.
During the Song Dynasty (960–1279), many of the common people could purchase various kinds of fireworks from market vendors, and grand displays of fireworks were also known to be held. In 1110, a large fireworks display in a martial demonstration was held to entertain Emperor Huizong of Song (r. 1100–1125) and his court. A record from 1264 states that a rocket-propelled firework went off near the Empress Dowager Gong Sheng and startled her during a feast held in her honor by her son Emperor Lizong of Song (r. 1224–1264).
Rocket propulsion was common in warfare, as evidenced by the Huolongjing compiled by Liu Bowen (1311–1375) and Jiao Yu (fl. c. 1350–1412). In 1240 the Arabs acquired knowledge of gunpowder and its uses from China. A Syrian named Hasan al-Rammah wrote of rockets, fireworks, and other incendiaries, using terms that suggested he derived his knowledge from Chinese sources, such as his references to fireworks as "Chinese flowers".
With the development of chinoiserie in Europe, Chinese fireworks began to gain popularity around the mid-17th century. Lev Izmailov, ambassador of Peter the Great, once reported from China: "They make such fireworks that no one in Europe has ever seen." In 1758, the Jesuit missionary Pierre Nicolas le Chéron d'Incarville, living in Beijing, wrote about the methods and composition on how to make many types of Chinese fireworks to the Paris Academy of Sciences, which revealed and published the account five years later. His writings would be translated in 1765, resulting in the popularization of fireworks and further attempts to uncover the secrets of Chinese fireworks.
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Wednesday, 4 January 2017
A new study by researchers from the UCSF Benioff Children's Hospital Research Institute (CHORI) shows that a modest 4 milligrams of extra zinc a day in the diet can have a profound, positive impact on cellular health that helps fight infections and diseases. This amount of zinc is equivalent to what biofortified crops like zinc rice and zinc wheat can add to the diet of vulnerable, nutrient deficient populations.
The study, published in the American Journal of Clinical Nutrition, was led by CHORI Senior Scientist Janet King, PhD. King and her team are the first to show that a modest increase in dietary zinc reduces oxidative stress and damage to DNA.
|Zinc Acetate. By Chemical interest (Own work (Original text: self-made)) [Public domain], via Wikimedia Commons|
"We were pleasantly surprised to see that just a small increase in dietary zinc can have such a significant impact on how metabolism is carried out throughout the body," says King. "These results present a new strategy for measuring the impact of zinc on health and reinforce the evidence that food-based interventions can improve micronutrient deficiencies worldwide."
Zinc is ubiquitous in our body and facilitates many functions that are essential for preserving life. It plays a vital role in maintaining optimal childhood growth, and in ensuring a healthy immune system. Zinc also helps limit inflammation and oxidative stress in our body, which are associated with the onset of chronic cardiovascular diseases and cancers.
Around much of the world, many households eat polished white rice or highly refined wheat or maize flours, which provide energy but do not provide enough essential micronutrients such as zinc. Zinc is an essential part of nearly 3,000 different proteins, and it impacts how these proteins regulate every cell in our body. In the absence of sufficient zinc, our ability to repair everyday wear and tear on our DNA is compromised.
In the randomized, controlled, six-week study the scientists measured the impact of zinc on human metabolism by counting DNA strand breaks. They used the parameter of DNA damage to examine the influence of a moderate amount of zinc on healthy living. This was a novel approach, different from the commonly used method of looking at zinc in the blood or using stunting and morbidity for assessing zinc status.
According to King, these results are relevant to the planning and evaluation of food-based solutions for mitigating the impact of hidden hunger and malnutrition. King believes that biofortification can be a sustainable, long-term solution to zinc deficiency.
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