Rosatom and the Ministry of Scientific Research and Technological Innovations of the Republic of Congo have signed a Memorandum of Understanding (MoU) on cooperation in the peaceful uses of nuclear energy. World-nuclear-news.org
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Geiger Readings for Feb 16, 2017
Ambient office = 56 nanosieverts per hourAmbient outside = 165 nanosieverts per hourSoil exposed to rain water = 162 nanosieverts per hourGarlic bulb from Central Market = 107 nanosieverts per hourTap water = 59 nanosieverts per hourFilter water = 52 nanosieverts per hour -
Researchers Use Organ-On-A-Chip To Study Radiation Damage To Gastrointestinal Tract
Nuclear radiation exposure from nuclear power plant accidents affects relatively few people. On the other hand, radiation treatment for cancer is widespread. It is important that we learn all we can about how radiation harms human beings, so we can find ways to repair the damage if possible. Animal models of radiation damage are not very useful in assessing radiation damage to humans but medical ethics prevent experimenting on people. Now a group of researchers have found a new way to improve our knowledge of the effects of radiation on human beings.
Researchers from the Wyss Institute for Biologically Inspired Engineering at Harvard University, Instituto Superior Técnico (IST, Portugal), Boston Children’s Hospital, and Harvard Medical School (HMS) have just published a study on their use of what is called an “organ-on-a-chip” to assess radiation damage to the human gastrointestinal tract.
An organ-on-a-chip is a “multi-channel 3-D microfluidic cell culture chip that simulates the activities, mechanics and physiological response of entire organs and organ systems.” (Wikipedia) The chip used by the researchers is transparent and contains two parallel microchannels which are separated by a porous extracellular matrix membrane. One of the channels is coated with epithelial cells from the lining of a human intestine. The other channel is lined with human endothelial cells that are similar to the cells lining blood vessels. The researchers refer to this type of organ-on-a-chip as a Gut Chip
Cell cultural media is injected into each of the channels. There are side chambers located long both of the channels. A suction is periodically applied to these side chambers to stretch the cells lining the channels. This is done to imitate the motions of a human intestine as food move through it. The cells in the channels spontaneously form intestinal villus-like structures and surface microvilli that serve to expand the cell surface area for nutrient exchange.
The researchers subjected the Gut Chip to eight Grays of radiation. A Gray is a measure of radiation absorption. An eight Gray dose is known to cause damage to the gastrointestinal tract of a human being. The Gut Chip showed a variety of indicators of cellular damage. These included cell death, generation of free radicals, double stranded DNA breaks, membrane lipids damage, loss of microvilli structure, and disruption of junctions between the protective mucous lining of the intestine and the nearby cells.
The endothelial cells in the Gut Chip showed more damage from the radiation than the epithelial cells. In the endothelial cells, the peak of cell death occurred twenty-four hours from the exposure while the epithelial cells showed peak cell death after forty eight hours. The conclusion drawn from these results is that the endothelium is more sensitive to radiation than the epithelium.
A coauthor of the study said, “This finding helps explain why other models of the human gut that don’t include endothelial cells generally fail to mimic the gut’s response to radiation injury. More studies are needed to confirm the link between endothelial and epithelial cell responses, but we think that free radicals generated by endothelial cell damage will prove to be the driving force behind epithelial cell damage, and this could serve as a target for future anti-radiation therapeutics.”
In the next stage of the research, the scientists injected dimethyloxaloylglycine (DMOG) into the Gut Chip before they exposed it to radiation. DMOG a drug known to protect animals against radiation damage in the gut by promoting the production of two proteins. The DMOG significantly reduced cell death, free radicals, lipid degredation and microvillus injury in both channels of the Gut Chip.
One of the researchers said, “Now that we have successfully tested a potential drug candidate in a human organ system, our goal is to use this chip to identify new radioprotective drugs by physiologically mimicking radiation damage in the gut.”
Another researcher said, “The grand vision for the future of this technology is to link different Organ Chips into a fully personalized body-on-chips model, where we’d be able to take cells from a patient and test which medicines will best protect all their organs from radiation, either higher doses from nuclear events or lower doses from off-target cancer treatment.”
The Founding Director of the Wyss Institute said, “This research marks an important advance bringing us closer to realizing our goal of creating clinically relevant chips for each major organ system that can help predict and prevent disease, and importantly, it meets a longstanding need for more human-relevant models of radiation toxicity that can be used to develop appropriate countermeasure therapies, which was the challenge raised by the Food and Drug Administration (FDA) when they funded our work.”
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Geiger Readings for Feb 15, 2017
Ambient office = 140 nanosieverts per hourAmbient outside = 79 nanosieverts per hourSoil exposed to rain water = 82 nanosieverts per hourYellow bell pepper from Central Market = 93 nanosieverts per hourTap water = 127 nanosieverts per hourFilter water = 103 nanosieverts per hour -
Nuclear Weapons 345 – Chinese Researchers Create Beam Of Tantalum-181 For Nuclear Weapons Research
I have blogged before about China’s nuclear arsenal and nuclear protocols. Basically, the Chinese have a few hundred nuclear warheads and various delivery options. They have chosen to maintain enough nuclear weapons to discourage anyone from attacking them with nuclear weapons but have a policy of not being the first to use nuclear weapons in a conflict. Since the deterioration of relations between Russia and the U.S., some parties in China believe that the Chinese arsenal should be expanded, and their nuclear policies revised.
The Chinese Academy of Sciences (CAS) just reported on an experiment carried out at the Heavy Ion Research Facility (HIRF) in Lanzhou. The HIRF fired a superheated beam of tantalum 181, a radioactive isotope of tantalum. The CAS said that the experiment was important to “meet a critical strategic demand of China’s national defense”.
One of the researchers said that it was very difficult to create a high-quality, high-output tantalum beam because tantalum melts at about three thousand degrees Celsius. It has been a problem to isolate the tantalum and generate a particle beam that was large enough to conduct experiments. Tantalum is almost as heavy as gold and they needed to use advanced magnetic technology to impart high velocity to the ions as well as control their movements.
A professor of nuclear science at Beijing Normal University who was not involved in the tantalum project said that the experiment was likely carried out to further the development of nuclear devices that contained tantalum. This type of nuclear weapons is called a “salted bomb.” The name is derived from the mediaeval practice of spreading salt on land in conquered nations. The salt prevented the growth of crops and, essentially, killed the land.
A salted bomb containing tantalum would release a cloud of radioactive isotopes much bigger than that released by a similar bomb without tantalum. The salted bomb cloud would spread over a larger area than the cloud from a conventional nuclear bomb. The fallout from a tantalum bomb would render the land uninhabitable for months. Cobalt has also been tested in previous salted bombs developed by Britain.
The professor went on to say, “The most likely application that I can think of [for the tantalum acceleration experiment] is in nuclear research. By generating a powerful beam of tantalum ions, we can observe how the metal interacts with other elements and change form in high-speed collisions. It simulates what will happen in a real nuclear reaction.”
China has expanded and modernized it nuclear arsenal in the past few years. It is dedicated to attaining the highest level of deterrence with the fewest nuclear weapons possible. They may feel that the development of salted bombs could assist in that goal.
Leo Szilard, a pioneer of nuclear weapons, first suggested the idea of salted bombs. He feared that their widespread use could poison so much of the Earth’s surface that the human race would not be able to survive. Some nuclear authorities have suggested that salted bombs could make a good doomsday device that a nation could threaten to detonate if they were attacked with nuclear weapons. There is great concern that a nuclear war could bring the end of human civilization. The use of salted bombs might guarantee it.
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Geiger Readings for Feb 14, 2017
Ambient office = 59 nanosieverts per hourAmbient outside = 114 nanosieverts per hourSoil exposed to rain water = 126 nanosieverts per hourCarrot from Central Market = 140 nanosieverts per hourTap water = 71 nanosieverts per hourFilter water = 49 nanosieverts per hour -
Nuclear Weapons 344 – Researchers At George Mason University Are Creating A Computer Model Of Public Behavior Following A Nuclear Strike On Manhattan
There have been books, movies and TV shows about the detonation of nuclear weapons in major urban centers. Much of the drama in such shows lies in how people react and cope after the attack. Now scientists are working on a huge computer simulation to try and better understand exactly how people would really react if they survived a nearby nuclear detonation.
The U.S. Defense Threat Reduction Agency (DTRA) is “…a combat support agency whose goal is to reduce the threat posed by weapons of mass destruction.” It’s parent agency is the U.S. Department of Defense. The DTRA awarded a grant of about half a million dollars to the Center for Social Complexity (CSC) last May. The CSC is located at George Mason University. The GMU is “…a specialized venue for pursuing interdisciplinary advanced research, discoveries, and inventions that support exploration and analysis of human social phenomena. The Center subscribes to the philosophy of exploiting synergistic interactions between purely theoretical and applied policy research.”
The purpose of the grant is to fund a study to develop a sophisticated computer simulation of how twenty million people would react in the first thirty days after a nuclear attack on New York City. The three-year project will follow millions of software agents as they make decisions and move around the simulated area as their needs, surroundings and social networks dictate. It is expected that most of them would stay near where they were when the bomb hit, follow emergency instructions and take care of injured people nearby.
William Kennedy, the lead researcher on the grant, said in an interview that the first step would be to do basic research and generate text descriptions on how the people, the infrastructure and the environment would be affected by the blast. Then they will begin to translate the descriptions into computer programs. His group has already created other computer models of natural disasters in similar-sized areas. They will be using an open source computer simulation program called MASON that was created at GMU for most of the modeling.
The research group is studying public responses to natural disasters in the U.S. over the past hundred years. Their model will be based on the detonation of a relatively small nuclear warhead of about ten kilotons of TNT in Manhattan. This is about the size of the bomb dropped on Hiroshima at the end of World War II. It is also about the size on the warheads that North Korea are testing.
The individual software agents are designed to act like people usually do in a major disaster. Their first priority is always to find and help other members of their family if they are nearby when the bomb hits. If they are at work, they will help and cooperate with people they work with. If they are in the midst of strangers, they will tend to form ad hoc “families” and work together. After the detonation, they will try to get out of their current area to find food, water and shelter.
The researchers are currently working on maps of New York City that contain infrastructure that the software agents might interact with including police stations, fire departments, government buildings, commercial establishments, road, bridges, schools, hospitals, etc. It is assumed that a small detonation at ground level will leave communication networks intact, so cell phones and land lines will be available.
Psychological effect such as fear, terror, depression, etc. will be included in the modeled behavior as well as physical injuries. Behavior will be modeled at five-minute intervals for the first few hours after the attack, then it will move on to modeling at fifteen-minute intervals. Considerable computational power will be required. The terms of the grant require that the researchers provide published papers and academic advancement of the two Ph.D candidates involved in the study.
