Posts Tagged ‘science’

By Ashley P. Taylor

During adulthood, the mouse brain manufactures new neurons in several locations, including the hippocampus and the subventricular zone of the forebrain. The hypothalamus, previously identified as an area with an important role in aging, also generates new neurons from neural stem cells. In a study published July 26 in Nature, Dongsheng Cai and his team at the Albert Einstein College of Medicine in New York connect the dots between these two observations, reporting that hypothalamic neural stem cells have widespread effects on the rate of aging in mice.

In what David Sinclair, who studies aging at Harvard Medical School and who was not involved in the work, calls a “Herculean effort,” the researchers “discovered that stem cells in the hypothalamus of the mouse play a role in overall health and life span,” he tells The Scientist.

Cai and his team found that killing hypothalamic neural stem cells accelerates aging, and transplantation of additional neural stem cells into the same brain region slows it down. Further, the stem cells’ anti-aging effects could be reproduced simply by administering the cells’ secreted vesicles, called exosomes, containing microRNAs (miRNAs).

“If this is true for humans, one could imagine a day when we are treated with these small RNAs injected into our bodies or even implanted with new hypothalamic stem cells to keep us younger for longer,” Sinclair adds.

Researchers who study aging have long been searching for a central location that controls the process system-wide. In a 2013 paper, Cai and his team reported aging-associated inflammation in the hypothalamus of the mouse, which they could experimentally manipulate to speed up or slow down various types of aging-related decline, from muscle endurance to cognitive skills.

This study, Cai says, suggested the hypothalamus might be that central locus in control of aging. The researchers wanted to understand more about how this region of the brain drives aging and what role hypothalamic neural stem cells might play in that process, so they undertook a series of experiments.

Age-defying stem cells

The researchers first confirmed that cells bearing protein markers of neural stem cells (Sox2 and Bmi1) were present in the hypothalamus of early-to-middle-aged mice (11 to 16 months old) and that the number of those cells decreased in older mice.

Next, they destroyed neuronal stem cells in the hypothalamus by injecting the third ventricle, adjacent to the hypothalamic region where the stem cells are found, with a lentivirus that converted an administered compound into a toxin in cells expressing the stem-cell marker Sox2. Three or four months later, the researchers compared a variety of aging-related measures, including muscle endurance, coordination, social behaviors, novel object recognition, and cognitive performance, between mice injected with the virus and various control groups of mice that received a brain injection of some sort but in which the toxin could not be produced and the hypothalamic stem cells were consequently not ablated.

The mice in the experimental group lost 70 percent of their hypothalamic stem cells and, based on results of the physiological tests, had accelerated aging. Mice with ablated hypothalamic stem cells also died earlier than control mice.

Next, the researchers implanted middle-aged mice with neural stem cells derived from newborn mice to see if the additional stem cells would slow aging. But the implanted stem cells almost all died, which the researchers believe was a result of the inflammatory environment of the aging hypothalamus. Newborn neuronal stem cells genetically engineered to withstand that environment, on the other hand, did survive, and mice implanted with those cells lived longer and performed better on aging-related measures than control mice.

“What’s cool about this study is that they specifically delete a population of cells in the hypothalamus of the brain . . . and they show pretty striking alterations in whole-body aging,” says Anna Molofsky, a psychiatrist at the University of California, San Francisco, who studies glial cells and whose graduate work focused on neuronal stem cells and aging. “That’s really showing that there’s a mechanism within the brain that’s regulating whole-body organismal aging,” she adds. Molofsky, who was not involved in the work, says that these results support the idea of the hypothalamus as a central regulator of aging.

Anti-aging mechanism

Although neural stem cells are known for their ability to produce new neurons, that doesn’t seem to be their primary method for protecting against aging. The anti-aging effects of these hypothalamic stem cells were visible at around four months—not long enough, the authors write, for significant adult neurogenesis to have taken place.

The authors looked instead for some other factor that might be responsible for the stem cells’ effects. In the hypothalamic neural stem cells, the researchers detected exosomes—secreted vesicles that can contain RNA and proteins—containing a variety of miRNAs, short RNA molecules that inhibit the expression of targeted genes. These exosomes were not present in non-stem cells of the hypothalamus.

To test the effects of the exosomes alone on aging, the researchers purified the vesicles from cultured hypothalamic neural stem cells and transplanted them into middle-aged mice, finding that the exosome-treated mice aged more slowly than vehicle-treated controls. They also found that the exosomes could ameliorate the aging symptoms of mice whose hypothalamic neurons had been ablated.

Cai says microRNAs could be a potential mechanism by which hypothalamic neural stem cells have such wide-ranging effects on aging, yet he believes that neurogenesis may also be involved.

Regardless of the mechanism, Molofsky says, “the medical applications could be pretty profound.” The phenotypes, such as muscle mass and skin thickness, affected by these stem cells are the same ones that cause age-related disease, she notes. “The fact that you can reverse that with a brain-specific modulation, potentially, in a cell type that one could pharmacologically target, I think potentially that could be very profound, assuming that the mouse work translates to humans.”

Y. Zhang et al., “Hypothalamic stem cells control ageing speed partly through exosomal miRNAs,” Nature, doi:10.1038/nature23282, 2017.

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There is a story in the Hebrew Bible that tells of God’s call for the annihilation of the Canaanites, a people who lived in what are now Jordan, Lebanon, Syria, Israel and the Palestinian territories thousands of years ago.

“You shall not leave alive anything that breathes,” God said in the passage. “But you shall utterly destroy them.”

But a genetic analysis published on Thursday has found that the ancient population survived that divine call for their extinction, and their descendants live in modern Lebanon.

“We can see the present-day Lebanese can trace most of their ancestry to the Canaanites or a genetically equivalent population,” said Chris Tyler-Smith, a geneticist with the Wellcome Trust Sanger Institute who is an author of the paper. “They derive just over 90 percent of their ancestry from the Canaanites.”

Dr. Tyler-Smith and an international team of geneticists and archaeologists recovered ancient DNA from bones belonging to five Canaanites retrieved from an excavation site in Sidon, Lebanon, that were 3,650 to 3,750 years old. The team then compared the ancient DNA with the genomes of 99 living people from Lebanon that the group had sequenced. It found that the modern Lebanese people shared about 93 percent of their ancestry with the Bronze Age Sidon samples.

The team published its results in The American Journal of Human Genetics.

“The conclusion is clear,” said Iosif Lazaridis, a geneticist at Harvard who was not involved in the study. “Based on this study it turns out that people who lived in Lebanon almost 4,000 years ago were quite similar to people who lived there today, to the modern Lebanese.”

Marc Haber, a postdoctoral fellow at the Wellcome Trust Sanger Institute in England and lead author on the study, said that compared with other Bronze Age civilizations, not much is known about the Canaanites.

“We know about ancient Egyptians and ancient Greeks, but we know very little about the ancient Canaanites because their records didn’t survive,” he said. Their writings may have been kept on papyrus, which did not stand the test of time as clay did. What is known about the Canaanites is that they lived and traded along the eastern coast of the present-day Mediterranean, a region that was known as the Levant.

“What we see is that since the Bronze Age, this ancestry, or the genetics of the people there, didn’t change much,” Dr. Haber said. “It changed a little, but it didn’t change much and that is what surprised me.”

At first the team was not sure if it would be able to retrieve DNA from the ancient skeletons, which were recovered from the hot and humid excavation site within the last 19 years. Dr. Haber had chosen more than two dozen bones from the site that looked promising and had them investigated for genetic material. It turned out that only five contained ancient DNA. All of those came from the petrous part of the temporal bone, which is the tough part of the skull behind the ear, from five different individuals.

After extracting that DNA, the team members compared it with a database that contained genetic information from hundreds of human populations. They then further compared their results with the genomes of the modern-day Lebanese population sample, which revealed what happened to the ancient Canaanite population.

“Genetics has the power to answer questions that historical records or archaeology are not able to answer,” Dr. Haber said.

He said researchers thought that migrations, conquests and the intermixing of Eurasian people — like the Assyrians, Persians or Macedonians — with the Canaanites 3,800 to 2,200 years ago might have contributed to the slight genetic changes seen in modern Lebanese populations. Still, the Lebanese retain most of their ancestral DNA from the Canaanites.

“It confirms the continuity of occupation and rooted tradition we have seen on-site, which was occupied from the 4th millennium B.C. right to the Crusader period,” Claude Doumet-Serhal, an archaeologist and director of the Sidon Excavation who is a co-author on the paper, said in an email.

She said that the archaeologists had found about 160 burials to date at their excavation site, which is in the heart of modern Sidon. They include graves and burials where a person was placed in a large jar, and they date to between 1900 and 1550 B.C. The genetic results further support the archaeological findings.

“We were delighted by the findings,” Dr. Doumet-Serhal said. “We are looking at the Canaanite society through 160 burials and at the same time uncovering a common past for all the people of Lebanon, whatever religion they belong to.”

https://mobile.nytimes.com/2017/07/27/science/ancient-canaanites-bible-lebanon.html?referer=http://m.facebook.com


I’m a Computer Science major in the school of Literature, Science, and the Arts. Eleven months ago, I knew nothing about nuclear engineering. In ten days, I’ll be interning at Sandia National Laboratories in Livermore, CA to work on a Helium-3 well counter. You might be wondering how I ended up here- I know that I am.

By Aditi Rajadhyaksha

I was pretty lost at the beginning of the Fall 2016 semester. I had just decided to major in Computer Science, which I was satisfied with. I enjoyed my Computer Science courses, but I felt out of place. I had just been accepted to the UROP program, which I was apprehensive about because I had heard many stories of friends who ended up with terrible UROP projects and even worse mentors. Boy, I had no idea what I was in for.

Fast forward a month and I’m on Professor Sara Pozzi’s project working with Dr. Patricia Schuster. I don’t know a single thing about nuclear engineering, but the field has always intrigued me, so I’m excited about the prospect of this project. Patricia has explained the project to me, and I sort of understand it, but not really. Luckily, I understand the first coding assignment, so I get to work on that


March 24, 2017. Our first measurement

As the months go by, I start understanding more and more of the project and get engaged in the work. I also start to get an idea of the magnitude of the importance of the field of nuclear engineering.

Rewind a week, then a month, then two months… research is hard. Things take time. Things always take longer than you think they will. Things never work the first time, and, if they do, something’s wrong. Some group members start getting frustrated with the pace of progress. Stress starts building. We were supposed to have stilbene data by the ANS Student Conference in April, but that might not happen.

As the months go by, I start understanding more and more of the project and get engaged in the work. I also start to get an idea of the magnitude of the importance of the field of nuclear engineering.

Rewind a week, then a month, then two months… research is hard. Things take time. Things always take longer than you think they will. Things never work the first time, and, if they do, something’s wrong. Some group members start getting frustrated with the pace of progress. Stress starts building. We were supposed to have stilbene data by the ANS Student Conference in April, but that might not happen.

At the student conference, I start to realize that I really enjoy this work. I’m beginning to think that this is something I could see myself doing for a long time. I mean, I submitted my data to a Science as Art contest held by the university. So, not only do I enjoy the work, but I think it’s art, too.

People respond really well to my ANS student conference talk. This tells me that this work is something that I’m good at. I want to start actively pursuing this.

At the conference, two CVT/DNNG upperclassmen, Evan and Kyle, tell me that they will be working at national laboratories this summer. I have heard about these national laboratories- they do amazing work, the best people in nuclear have worked at them, and Patricia did her graduate work at Sandia National Laboratories. Now I want to work at one really badly. My sights are set on it for my summer 2018 internship. Also, I feel like I’ve been robbed of an award for my talk at the conference. Vengeance starts brewing.

In April, I find out that I’ve been accepted as a summer CVT undergraduate fellow. I am ecstatic! I will get to continue working on this project that I have gotten really into. And I will get to continue working with Patricia. And I win an award for the best poster in my session at the UROP symposium. More evidence that I am good at what I am doing and that my passion for it is being conveyed to others.

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I started the summer with three goals:
1.Take measurements of the stilbene organic scintillator detector.
2.Give an award-winning talk at the INMM conference.
3.Learn how to drive (this is something that they do not teach you when you grow up in New York City).

My CVT internship began with the MCNP-PoliMi workshop. That was exciting for me because I had never been exposed to MCNP prior to this and had heard a lot about it. I was able to become familiar with the program and meet people that had traveled far distances to Ann Arbor for this workshop.

Throughout the internship, I continued working on my temperature dependence of organic scintillator detectors project. We took measurements of the stilbene organic scintillator detector and a plastic organic scintillator detector along with the EJ-309 liquid organic scintillator detector again. I improved upon and wrote new data analysis scripts in Python.

Then, it was time for the INMM conference! It was an amazing opportunity and an amazing conference. I met a lot of people, exchanged several business cards, and heard a lot of interesting talks. I especially enjoyed hearing some of the policy talks because that’s something I don’t normally get to hear about.

The best was hearing Sieg Hecker’s talk. It was an honor. Hearing about his experiences after the Cold War and hearing him talk about the current state of nuclear policy and weapons showed me the importance of this work. I left inspired.

I spent a lot of time at the national lab exhibits because I have a one-track mind, and that mind was set on getting contacts at national labs in order to secure myself an internship for summer 2018. I also met with some companies that are also doing impressive and groundbreaking work, so those are other places to pursue for next summer.

I presented my work. It was a great experience because I got to hear suggestions and answer questions from audience members and present my work to some CVT and DNNG members for the first time. I was also the only undergraduate presenter from the DNNG and in my session, which I’m proud of.

I met my judge during a social event. I asked him what I did well and how to improve. He told me that I had the best slides by far and that I had the best presentation material. He said that I held myself well on stage and had great poise and public speaking skills. However, he was disappointed that I read from my notes when presenting. He said that he knew that I knew the information and did not need those notes.

This information is invaluable. For the future, I know what I do well, and I know where to improve. Hopefully, next year when I implement the judge’s advice I can win an award!

But best of all, Patricia scored me an internship at Sandia National Laboratories starting in August. She introduced me to Dr. Scott Kiff, who, after hearing about the work I did during the year and during my CVT internship, offered me a position to work on his well counter project for five weeks. As you know, this is a dream come true for me. I get to work on a new project at a national lab, learn about well counters, and get a taste for what it would be like to work at Sandia at Livermore. I will get to meet new people there and network and hopefully earn a position there next summer. I also want to obtain some of the new organic glass scintillator material that was just developed there to characterize its temperature dependence. And the best part is that Professor Pozzi agreed to fund me. It really can’t get any better than this.

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I was lost at the beginning of this year. And I really didn’t know what I was getting into when I sent that email to Patricia asking to hear about her UROP project. Little did I know it would be a life-changing experience in which I would find my place and my passion.

For so long I’ve had such a hard time finding something that I really enjoy in a place where I feel like I really belong. I spent countless hours trying to come up with a passion for myself when writing my college essays, when selecting my freshman year classes, when pondering potential careers. Today I realize that I have finally found it. I’ve found something that I do well and that I love doing and that I feel passionate about with a group of some of the nicest and smartest people that I have ever met.

I watched my friends take jobs in marketing and finance and at big commercial tech companies and struggled to do the same. Those jobs didn’t appeal to me because they didn’t help anything or anybody. In fact, many of those jobs seem to make life harder for people. I guess it was the altruist that my parents and family raised in me that told me that I didn’t belong in one of those professions doing that work.

But this field is different. As I learned from being at the INMM Conference and listening to Sieg Hecker’s talk, this work matters so much to everybody. The work that I do can help countless people, and has the potential to even save the planet. This makes me feel like I’m doing really important work, which in turn pushes me to work harder and produce better and better work every day.

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I started the summer with three goals:
1.Take measurements of the stilbene organic scintillator detector.
2.Give an award-winning talk at the INMM conference.
3.Learn how to drive.

I took measurements of the stilbene organic scintillator detector, and I learned how to drive. I am still working towards winning an award, and I am coming closer every day.

I am very excited to start this new project at Sandia. This will help me work towards my goals of excelling in this field and contributing to the safety of the United States and the world.

At the end of this internship, I know two things for sure: 1. I am the luckiest person in the world. 2. That well counter has no idea what’s coming for it.

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Thank you to Patricia Schuster, who has done so much for me. From teaching me everything I know about nuclear engineering, to pushing me to give talks and be a better researcher, to advocating for me to the DNNG and CVT, to getting me the CVT internship, to getting me the position at Sandia, and for being there for me when it gets hard to be a woman in engineering. She has been instrumental in helping me find my passion and my purpose and in making me the researcher, nuclear engineer and data scientist that I am today.

https://itsinterestingdotcom.wordpress.com/wp-admin/post-new.php

That warm, fuzzy feeling you get when you’re being generous or charitable happens when the brain areas involved in generosity and in happiness synchronise.

No one likes a Scrooge. It’s been shown that generous people make more popular partners, and researchers have also honed in on the brain areas linked to generosity.

But fundamentally, being generous means spending resources – be they time, energy or money – on another person that you could be spending on yourself. According to conventional economic theory, this is very surprising: prioritising others over yourself might leave you with fewer resources.

Now neuroscientists have pinpointed how generosity is linked to happiness on a neural level, in a study in the journal Nature Communications.

In a study of 50 people, half were given the task of thinking about how they’d like to spend 100 Swiss Francs (£80) on themselves over the next four weeks. The other half were told to think about how they’d like to spend it on someone else – for example, a partner, friend or relative. They took a test to measure their subjective level of happiness before and after the experiment.

The people who were told to spend the money on others had a bigger mood boost than the group who had planned more treats for themselves.

Immediately after this test, the participants took part in another one. They were put in an fMRI scanner and their brain activity was measured while they were asked questions about how to distribute money between themselves and someone else they knew.

They were given the chance to accept offers such as giving their chosen person a present of 15 Swiss Francs even if it cost them 20 Francs. The people who had been in the ‘generous’ group in the first experiment tended to be more generous in this activity.

The decisions people made in the experiment weren’t just hypothetical, they had real consequences.

“The people were told that one of those options would be randomly chosen and then realised. So, for example they would have to pay 20 Francs and we would send other person the 15 Francs with a letter explaining why they were receiving it,” study author Soyoung Park of the University of Lübeck, Germany, told IBTimes UK.

The scans revealed the brain areas that were most active during the acts of generosity. The area associated with generosity – the temporo-parietal junction – and an area associated with happiness – the ventral striatum – both lit up particularly strongly during the fMRI scans. In addition, the activity of the two regions synchronised.

People tend not to realise how happy generous giving will make them, the researchers conclude.

“In everyday life, people underestimate the link between generosity and happiness and therefore overlook the benefits of prosocial spending. When asked, they respond that they assume there would be a greater increase in happiness after spending money on themselves and after spending greater amounts of money,” the authors write in the study.

“Our study provides behavioural and neural evidence that supports the link between generosity and happiness. Our results suggest that, for a person to achieve happiness from generous behaviour, the brain regions involved in empathy and social cognition need to overwrite selfish motives in reward-related brain regions. These findings have important implications not only for neuroscience but also for education, politics, economics and health.”

http://www.ibtimes.co.uk/warm-glow-you-get-generosity-real-scientific-phenomenon-1629891

By Dan Taylor

It’s a tiny little animal, but it is virtually impossible to kill, and scientists think it may one day outlive us. It’s the tardigrade, also known as the water bear, and these minuscule animals may not look like much, but they’re a lot tougher than we fragile humans are, the University of Oxford said in a statement after publishing a new paper on the animal.

Tardigrades have been known to survive the toughest conditions possible, including extreme heat, temperatures just barely above absolute zero, and even the vacuum of space. They’re known as the toughest critter on the planet, and this new study claims that they may very well be the last survivors of Earth, still kicking even after all the other creatures on Earth – including us – have perished.

And the tardigrade has lived for a very long time, certainly longer than the million years or so we’ve been around. Scientists have found tardigrade specimens in sediments that are dated between 100 and 520 million years old, so they’ve been around since the dinosaurs.

The full statement from the university follows below.

The world’s most indestructible species, the tardigrade, an eight-legged micro-animal, also known as the water bear, will survive until the Sun dies, according to a new Oxford University collaboration.

The new study published in Scientific Reports, has shown that the tiny creatures, will survive the risk of extinction from all astrophysical catastrophes, and be around for at least 10 billion years – far longer than the human race.

Although much attention has been given to the cataclysmic impact that an astrophysical event would have on human life, very little has been published around what it would take to kill the tardigrade, and wipe out life on this planet.

The research implies that life on Earth in general, will extend as long as the Sun keeps shining. It also reveals that once life emerges, it is surprisingly resilient and difficult to destroy, opening the possibility of life on other planets.

Tardigrades are the toughest, most resilient form of life on earth, able to survive for up to 30 years without food or water, and endure temperature extremes of up to 150 degrees Celsius, the deep sea and even the frozen vacuum of space. The water-dwelling micro animal can live for up to 60 years, and grow to a maximum size of 0.5mm, best seen under a microscope. Researchers from the Universities of Oxford and Harvard, have found that these life forms will likely survive all astrophysical calamities, such as an asteroid, since they will never be strong enough to boil off the world’s oceans.

Three potential events were considered as part of their research, including; large asteroid impact, and exploding stars in the form of supernovae or gamma ray bursts.

Asteroids

There are only a dozen known asteroids and dwarf planets with enough mass to boil the oceans (2×10^18 kg), these include (Vesta 2×10^20 kg) and Pluto (10^22 kg), however none of these objects will intersect the Earth’s orbit and pose a threat to tardigrades.

Supernova

In order to boil the oceans an exploding star would need to be 0.14 light-years away. The closest star to the Sun is four light years away and the probability of a massive star exploding close enough to Earth to kill all forms of life on it, within the Sun’s lifetime, is negligible.

Gamma-Ray bursts

Gamma-ray bursts are brighter and rarer than supernovae. Much like supernovas, gamma-ray bursts are too far away from earth to be considered a viable threat. To be able to boil the world’s oceans the burst would need to be no more than 40 light-years away, and the likelihood of a burst occurring so close is again, minor.

Dr Rafael Alves Batista, Co-author and Post-Doctoral Research Associate in the Department of Physics at Oxford University, said: ‘Without our technology protecting us, humans are a very sensitive species. Subtle changes in our environment impact us dramatically. There are many more resilient species’ on earth. Life on this planet can continue long after humans are gone.

‘Tardigrades are as close to indestructible as it gets on Earth, but it is possible that there are other resilient species examples elsewhere in the universe. In this context there is a real case for looking for life on Mars and in other areas of the solar system in general. If Tardigrades are earth’s most resilient species, who knows what else is out there.’

Dr David Sloan, Co-author and Post-Doctoral Research Associate in the Department of Physics at Oxford University, said: ‘A lot of previous work has focused on ‘doomsday’ scenarios on Earth – astrophysical events like supernovae that could wipe out the human race. Our study instead considered the hardiest species – the tardigrade. As we are now entering a stage of astronomy where we have seen exoplanets and are hoping to soon perform spectroscopy, looking for signatures of life, we should try to see just how fragile this hardiest life is. To our surprise we found that although nearby supernovae or large asteroid impacts would be catastrophic for people, tardigrades could be unaffected. Therefore it seems that life, once it gets going, is hard to wipe out entirely. Huge numbers of species, or even entire genera may become extinct, but life as a whole will go on.’

In highlighting the resilience of life in general, the research broadens the scope of life beyond Earth, within and outside of this solar system. Professor Abraham Loeb, co-author and chair of the Astronomy department at Harvard University, said: ‘It is difficult to eliminate all forms of life from a habitable planet. The history of Mars indicates that it once had an atmosphere that could have supported life, albeit under extreme conditions. Organisms with similar tolerances to radiation and temperature as tardigrades could survive long-term below the surface in these conditions. The subsurface oceans that are believed to exist on Europa and Enceladus, would have conditions similar to the deep oceans of Earth where tardigrades are found, volcanic vents providing heat in an environment devoid of light. The discovery of extremophiles in such locations would be a significant step forward in bracketing the range of conditions for life to exist on planets around other stars.’

Chinese scientists have teleported an object from Earth to a satellite orbiting 300 miles away in space, in a demonstration that has echoes of science fiction.

The feat sets a new record for quantum teleportation, an eerie phenomenon in which the complete properties of one particle are instantaneously transferred to another – in effect teleporting it to a distant location.

Scientists have hailed the advance as a significant step towards the goal of creating an unhackable quantum internet.

“Space-scale teleportation can be realised and is expected to play a key role in the future distributed quantum internet,” the authors, led by Professor Chao-Yang Lu from the University of Science and Technology of China, wrote in the paper.

The work may bring to mind Scotty beaming up the Enterprise crew in Star Trek, but there is no prospect of humans being able to materialise instantaneously at remote locations any time soon. The teleportation effect is limited to quantum-scale objects, such as fundamental particles.

In the experiment, photons were beamed from a ground station in Ngari in Tibet to China’s Micius satellite, which is in orbit 300 miles above Earth.

The research hinged on a bizarre effect known as quantum entanglement, in which pairs of particles are generated simultaneously meaning they inhabit a single, shared quantum state. Counter-intuitively, this twinned existence continues, even when the particles are separated by vast distances: any change in one will still affect the other.

Scientists can exploit this effect to transfer information between the two entangled particles. In quantum teleportation, a third particle is introduced and entangled with one of the original pair, in such a way that its distant partner assumes the exact state of the third particle.

For all intents and purposes, the distant particle takes on the identity of the new particle that its partner has interacted with.

Quantum teleportation could be harnessed to produce a new form of communication network, in which information would be encoded by the quantum states of entangled photons, rather than strings of 0s and 1s. The huge security advantage would be that it would be impossible for an eavesdropper to measure the photons’ states without disturbing them and revealing their presence.

Ian Walmsley, Hooke professor of experimental physics at Oxford University, said the latest work was an impressive step towards this ambition. “This palpably indicates that the field isn’t limited to scientists sitting in their labs thinking about weird things. Quantum phenomena actually have a utility and can really deliver some significant new technologies.”

Scientists have already succeeded in creating partially quantum networks in which secure messages can be sent over optical fibres. However, entanglement is fragile and is gradually lost as photons travel through optical fibres, meaning that scientists have struggled to get teleportation to work across large enough distances to make a global quantum network viable.

The advantage of using a satellite is that the particles of light travel through space for much of their journey. Last month, the Chinese team demonstrated they could send entangled photons from space to Earth. The latest work does the reverse: they sent photons from the mountaintop base to the satellite as it passed directly overhead.

Transmitting into space is more difficult as turbulence in the Earth’s atmosphere can cause the particles to deviate, and when this occurs at the start of their journey they can end up further off course.

The latest paper, published on the Arxiv website, describes how, more than 32 days, the scientists sent millions of photons to the satellite and achieved teleportation in 911 cases.

“This work establishes the first ground-to-satellite up-link for faithful and ultra-long-distance quantum teleportation, an essential step toward global-scale quantum internet,” the team write.

A number of teams, including the European Space Agency and Canadian scientists, have similar quantum-enabled satellites in development, but the latest results suggest China is leading the way in this field.

https://www.theguardian.com/science/2017/jul/12/scotty-can-you-beam-me-up-scientists-teleport-photons-300-miles-into-space#img-1

By Emily Underwood

Viewed under a microscope, your tongue is an alien landscape, studded by fringed and bumpy buds that sense five basic tastes: salty, sour, sweet, bitter, and umami. But mammalian taste buds may have an additional sixth sense—for water, a new study suggests. The finding could help explain how animals can tell water from other fluids, and it adds new fodder to a centuries-old debate: Does water have a taste of its own, or is it a mere vehicle for other flavors?

Ever since antiquity, philosophers have claimed that water has no flavor. Even Aristotle referred to it as “tasteless” around 330 B.C.E. But insects and amphibians have water-sensing nerve cells, and there is growing evidence of similar cells in mammals, says Patricia Di Lorenzo, a behavioral neuroscientist at the State University of New York in Binghamton. A few recent brain scan studies also suggest that a region of human cortex responds specifically to water, she says. Still, critics argue that any perceived flavor is just the after-effect of whatever we tasted earlier, such as the sweetness of water after we eat salty food.

“Almost nothing is known” about the molecular and cellular mechanism by which water is detected in the mouth and throat, and the neural pathway by which that signal is transmitted to the brain, says Zachary Knight, a neuroscientist at the University of California, San Francisco. In previous studies, Knight and other researchers have found distinct populations of neurons within a region of the brain called the hypothalamus that can trigger thirst and signal when an animal should start and stop drinking. But the brain must receive information about water from the mouth and tongue, because animals stop drinking long before signals from the gut or blood could tell the brain that the body has been replenished, he says.

In an attempt to settle the debate, Yuki Oka, a neuroscientist at the California Institute of Technology in Pasadena, and colleagues searched for water-sensing taste receptor cells (TRCs) in the mouse tongue. They used genetic knockout mice to look for the cells, silencing different types of TRCs, then flushing the rodents’ mouths with water to see which cells responded. “The most surprising part of the project” was that the well-known, acid-sensing, sour TRCs fired vigorously when exposed to water, Oka says. When given the option of drinking either water or a clear, tasteless, synthetic silicone oil, rodents lacking sour TRCs took longer to choose water, suggesting the cells help to distinguish water from other fluids.

Next, the team tested whether artificially activating the cells, using a technique called optogenetics, could drive the mice to drink water. They bred mice to express light-sensitive proteins in their acid-sensing TRCs, which make the cells fire in response to light from a laser. After training the mice to drink water from a spout, the team replaced the water with an optic fiber that shone blue light on their tongues. When the mice “drank” the blue light, they acted as though they were tasting water, Oka says. Some thirsty mice licked the light spout as many as 2000 times every 10 minutes, the team reports this week in Nature Neuroscience.

The rodents never learned that the light was just an illusion, but kept drinking long after mice drinking actual water would. That suggests that although signals from TRCs in the tongue can trigger drinking, they don’t play a role in telling the brain when to stop, Oka says.

More research is needed to precisely determine how the acid-sensing taste buds respond to water, and what the mice experience when they do, Oka says. But he suspects that when water washes out saliva—a salty, acidic mucus—it changes the pH within the cells, making them more likely to fire.

The notion that one of the ways animals detect water is by the removal of saliva “makes a lot of sense,” Knight says. But it is still only one of many likely routes for sensing water, including temperature and pressure, he adds.

The “well-designed, intriguing” study also speaks to a long-standing debate over the nature of taste, Di Lorenzo says. When you find a counterexample to the dominant view that there are only five basic taste groups, she says, “it tells you you need to go back to the drawing board.”

http://www.sciencemag.org/news/2017/05/scientists-discover-sixth-sense-tongue-water