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Batman: Arkham Origins
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Scientists Report First Success in Cloning Human Stem Cells
It’s been 17 years since Dolly the sheep was cloned from a mammary cell. And now scientists applied the same technique to make the first embryonic stem cell lines from human skin cells.
Ever since Ian Wilmut, an unassuming embryologist working at the Roslin Institute just outside of Edinburgh stunned the world by cloning the first mammal, Dolly, scientists have been asking – could humans be cloned in the same way? Putting aside the ethical challenges the question raised, the query turned out to involve more wishful thinking than scientific success. Despite the fact that dozens of other species have been cloned using the technique, called nuclear transfer, human cells have remained stubbornly resistant to the process.
Until now. Shoukhrat Mitalipov, a professor at Oregon Health & Science University and his colleagues report in the journal Cell that they have successfully reprogrammed human skin cells back to their embryonic state. The purpose of the study, however, was not to generate human clones but to produce lines of embryonic stem cells. These can develop into muscle, nerve, or other cells that make up the body’s tissues. The process, he says, took only a few months, a surprisingly short period to reach such an important milestone.
Nuclear transfer involves inserting a fully developed cell – in Mitalipov’s study, the cells came from the skin of fetuses – into the nucleus of an egg, and then manipulating the egg to start dividing, a process that normally only occurs after it has been fertilized by a sperm. After several days, the ball of cells that results contains a blanket of embryonic stem cells endowed with the genetic material of the donor skin cell, which have the ability to generate every cell type from that donor. In Dolly’s case, those cells were allowed to continue developing into an embryo that was then transferred to a ewe to produce a cloned sheep. But Mitalipov says his process with the human cells isn’t designed to generate a human clone, but rather just to create the embryonic stem cells. These could then be manipulated to create heart, nerve or other cells that can repair or treat disease.
“I think this is a really important advance,” says Dieter Egli, an investigator at the New York Stem Cell Foundation. “I have a very high confidence that versions of this technique will work very well; it’s something that the field has been waiting for.” Egli is among the handful of scientists who have been working to perfect the technique with human cells and in 2011, succeeded in producing human stem cells, but with double the number of chromosomes. In 2004, Woo Suk Hwang, a veterinary scientist at Seoul National University, claimed to have succeeded in achieving the feat, but later admitted to faking the data. Instead of generating embryonic stem cell lines via nuclear transfer, Hwang’s group produced the stem cells from days-old embryos, a technique that had already been established by James Thomson at University of Wisconsin in 1998.
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X-ray vision tracks lightning bursts
Blink and you’ve missed it. Researchers in the US have captured the world’s first X-ray images of lightning, by creating a special camera that can capture radiation at 10 million frames per second. They presented their new findings at the American Geophysical Union (AGU) Fall Meeting in San Francisco and they say that this new view of lightning could help to solve some of the mysteries of this spectacular natural phenomenon.
The research was carried out at the International Center for Lightning Research and Testing, located in Florida. It is one of the few sites in world where lightning is initiated and studied under controlled conditions. By firing rockets with trailing wires into thunder clouds, scientists are able to generate electric fields that are large enough to trigger bolts of lightning, which then propagate back down towards the rocket launch tower.
Joseph Dwyer and colleagues at the Florida Institute of Technology became interested in the fact that lightning emits X-rays as it propagates through the air, a phenomenon that was only noted in the past decade. But given that X-ray sources in lightning travel through the Earth’s atmosphere at velocities approaching the speed of light, it is difficult to catch them on camera before they disappear. In addition, they cannot be imaged with standard mirrors and lenses because huge amounts of material are required to prevent X-rays and gamma rays from entering through the sides of a camera.
Dwyer’s team has created a customized camera that has 30 detectors made from a combination of sodium iodide and photomultiplier tubes, each measuring 3 × 3 inch. The device, which is approximately the size of a standard refrigerator, is also equipped with a 3 inch pinhole aperture, and can record X-rays at 10 million frames per second. “This is actually a very old technique for making images, like that seen in a camera obscura,” Dwyer says.
During July and August this year, Dwyer’s team studied four rocket-triggered lightning flashes at the Florida test site. Each flash lasted for approximately two seconds and the resulting sequences of images revealed that X-rays emerged primarily from the vicinity of the lightning tip as it propagated towards the Earth. As the lightning crashed into the control tower it also triggered large bursts of gamma radiation, which were also captured by the camera.
“For the first time we’re catching a glimpse of lightning in the X-ray emission,” says Dwyer. “We’re seeing lightning as Superman would see it with his X-ray vision”.
Credit: James Dacey/physicsworld.com
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LotR 30 day challenge | Favourite Location: Minas Morgul
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