Daily Archives: 6 Jan 2021

Biology

How Earth’s Oddest Mammal Got to be so Bizarre? (Biology)

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Often considered the world’s oddest mammal, Australia’s beaver-like, duck-billed platypus exhibits an array of bizarre characteristics: it lays eggs instead of giving birth to live babies, sweats milk, has venomous spurs and is even equipped with 10 sex chromosomes. Now, an international team of researchers led by University of Copenhagen has conducted a unique mapping of the platypus genome and found answers regarding the origins of a few of its stranger features.

It lays eggs, but nurses, it is toothless, has a venomous spur, has webbed feet, fur that glows and has 10 sex chromosomes. Ever since Europeans discovered the platypus in Australia during the late 1700’s, the quirky, duck-billed, semiaquatic creature has baffled scientific researchers.

Modern day researchers are still trying to understand how the platypus — often considered to be the world’s oddest mammal — got to be so unique. Their understandings have now advanced, to a great degree. For the first time, an international team of researchers, led by University of Copenhagen biologists, has mapped a complete platypus genome. The study is published in the scientific journal, Nature.

“The complete genome has provided us with the answers to how a few of the platypus’ bizarre features emerged. At the same time, decoding the genome for platypus is important for improving our understanding of how other mammals evolved — including us humans. It holds the key as to why we and other eutheria mammals evolved to become animals that give birth to live young instead of egg-laying animals,” explains Professor Guojie Zhang of the Department of Biology.

The platypus belongs to an ancient group of mammals — monotremes — which existed millions of years prior to the emergence of any modern-day mammal.

“Indeed, the platypus belongs to the Mammalia class. But genetically, it is a mixture of mammals, birds and reptiles. It has preserved many of its ancestors’ original features — which probably contribute to its success in adapting to the environment they live in,” says Professor Zhang.

Lays eggs, sweats milk and has no teeth

One of the platypus’ most unusual characteristics is that, while it lays eggs, it also has mammary glands used to feed its babies, not through nipples, but by milk — which is sweat from its body.

During our own evolution, we humans lost all three so-called vitellogenin genes, each of which is important for the production of egg yolks. Chickens on the other hand, continue to have all three. The study demonstrates that platypuses still carry one of these three vitellogenin genes, despite having lost the other two roughly 130 million years ago. The platypus continues to lay eggs by virtue of this one remaining gene. This is probably because it is not as dependent on creating yolk proteins as birds and reptiles are, as platypuses produce milk for their young.

In all other mammals, vitellogenin genes have been replaced with casein genes, which are responsible for our ability to produce casein protein, a major component in mammalian milk. The new research demonstrates that the platypus carries casein genes as well, and that the composition of their milk is thereby quite similar to that of cows, humans and other mammals.

“It informs us that milk production in all extant mammal species has been developed through the same set of genes derived from a common ancestor which lived more than 170 million years ago — alongside the early dinosaurs in the Jurassic period,” says Guojie Zhang.

Another trait that makes the platypus so unique is that, unlike the vast majority of mammals, it is toothless. Although this monotremes’ nearest ancestors were toothed, the modern platypus is equipped with two horn plates that are used to mash food. The study reveals that the platypus lost its teeth roughly 120 million years ago, when four of the eight genes responsible for tooth development disappeared.

Only animal with 10 sex chromosomes

Yet another platypus oddity investigated by the researchers was how their sex is determined. Both humans and every other mammal on Earth have two sex chromosomes that determine sex – the X and Y chromosome system in which XX is female and XY is male. The monotremes, however, including our duck-billed friends from Down Under, have 10 sex chromosomes, with five Y and five X chromosomes.

Thanks to the near-complete chromosomal level genomes, researchers can now suggest that these 10 sex chromosomes in the ancestors of the monotremes were organized in a ring form which was later broken away into many small pieces of X and Y chromosomes. At the same time, the genome mapping reveals that the majority of monotreme sex chromosomes have more in common with chickens than with humans. But what it shows, is an evolutionary link between mammals and birds.

PLATYPUS FACTS

  • The platypus is endemic to eastern Australia and Tasmania. It is a protected species and classified by the IUCN as near-threatened.
  • Among the reasons why platypuses are considered mammals: they have mammary glands, grow hair and have three bones in their middle ears. Each trait helps to define a mammal.
  • The platypus belongs to the mammalian order monotreme, so named because monotremes use a singular opening for urination, defecation and sexual reproduction.
  • The animal is an excellent swimmer and spends much of its time hunting for insects and shellfish in rivers.
  • Its distinctive beak is filled with electrical sensors which are used to locate prey in muddy river beds.
  • The male platypus has a venomous spur behind each of its hind legs. The venom is poisonous enough to kill a dog and is deployed when males fight for territory.
  • Another 2020 study demonstrated that platypus fur is fluorescent. The animal’s brown fur reflects a blue-green color when placed under UV light. (source: https://doi.org/10.1515/mammalia-2020-0027)

ABOUT THE STUDY

  • Advanced gene sequencing technology that combines numerous cutting-edge methods has allowed the research team to map a near-complete genome at the chromosomal level from both the platypus and its cousin, the echidna– the only two currently living types of monotreme animals. The gene data fills in 90 percent of the gaps in previous genetic mappings. Over 96% of the genome sequences are placed in the chromosomes now.
  • The researchers have compared the monotreme genes and genomes from chickens, humans, rats, Tasmanian devils and lizards.
  • In addition to Yang Zhou (lead author) and Guojie Zhang of the University of Copenhagen, the research was carried out by, among others: Linda Shearwin-Whyatt of The University of Adelaide (Australia) and Jing Li of Zhejiang University (China). A complete list of the authors can be found in the research article.
  • The study has just been published in the prestigious scientific journal, Nature.

Reference: Zhou, Y., Shearwin-Whyatt, L., Li, J. et al. Platypus and echidna genomes reveal mammalian biology and evolution. Nature (2021). https://doi.org/10.1038/s41586-020-03039-0

Provided by Faculty of Science – University of Copenhagen

Psychology

Why We Use Our Smartphone at Cafés (Psychology)

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Why do people fiddle with their smartphones when they’re with other people? Researchers have identified three main reasons.

Maybe you’re like us. We’re the folks who are on our smartphones almost all the time, even when we’re with others. We know it annoys a lot of people, but we do it anyway. Why?

Researchers at NTNU have looked at why people in cafés pull out their phones, and how this affects café life. The three main reasons they identified are:

  • to delay or pause a conversation (interaction suspension).
  • to get out of a conversation (deliberately shielding interaction).
  • to share something with others (accessing shareables).

But what does that actually mean?

Interwoven with everything else

The smartphone is the world’s most ubiquitous personal tech gizmo. The vast majority of adults have one.

“This makes the smartphone important, both socially and sociologically,” says Ida Marie Henriksen, a postdoctoral fellow and first author of a new article.

She is affiliated with NTNU’s Department of Interdisciplinary Studies of Culture, and wrote the newly published article with Professor Aksel Tjora and Marianne Skaar, a PhD candidate from the Department of Sociology and Political Science.

The use of smartphones is connected to so many of our activities, both ones we do alone and ones we do with others. We look for tempting cafés online, pay for the bus ticket to the café with it, invite friends to come join us, use the phone to identify the music that the café is playing, and lots of other things.

Smartphones give us even better opportunities to be social. But they also enable us to distance ourselves from others.

Smartphones in the café

The researchers visited with 52 people at cafés in Trondheim, and interviewed them in depth about their mobile phone use and how they interacted with other people.

“We focused exclusively on people who seemed to know each other from before and who met to socialize. In addition, we observed 108 other meetings at a distance, kind of like research flies on the wall,” says Skaar.

“We focused exclusively on people who seemed to know each other from before and who met to socialize.”

By design, cafés are a place where you can be especially social with others. But some people use it instead as a place to hide away with a good drink for a while and keep a suitable distance from people, or as a workplace, preferably with a laptop or tablet in addition to the ubiquitous mobile phone.

So what do the three main types of cell phone use involve?

  1. Suspending interaction

Delaying interaction is what happens when we interrupt a conversation with our café partner to check an email, a phone conversation, a picture on Snapchat or just to make sure we haven’t missed anything on social media the last few minutes.

This is also called “phubbing” (from phone + snubbing), when the phone gets your attention instead of the live person you’re with.

How this behaviour is perceived depends on how the conversation partners understand the situation. You can get annoyed about it and see it as rude. But that’s not necessarily the case.

“How this behaviour is perceived depends on how the conversation partners understand the situation.”

“On the one hand, how you suspend your interaction plays a role. If you explain to the person you’re with why you have to postpone your physical interaction, it’s perceived as more polite than if you just disappear and start “phubbing,” that is, phoning someone else and ignoring the person who’s physically present. At the same time, some people may appreciate a short break from a longer conversation, and using the phone can also be a natural, interwoven part of the social interaction that takes place in the café,” says Tjora.

  1. Deliberately shielding interaction

This is a slightly different, more subtle way of using the phone than suspending interaction exposure.

“When the person you’re with gets busy on their smartphone, the other person in the social setting can pick up their smartphone to demonstrate that they’re busy too and not being involuntarily left to themselves. Or if you’re in a group, you can pick up your phone to avoid a conversation topic by signalling that you are busy. The smartphone offers a break from face-to-face social situations,” says Henriksen.

“Smartphones offer a break from face-to-face social situations.”

Some of us take this a step further by keeping our cell phone in silent mode. Then we can pretend we’ve received an important message or conversation, and that we have to hurry to answer it, maybe even leaving the company we’re sitting with.

You can escape a lot of boring meetings this way. But it’s not exactly pleasant.

  1. Content sharing

This is the more pleasant or useful sharing side of using a phone and can sometimes be almost the opposite of taking a break from interacting.

“When you take a selfie together, or show pictures of your new girlfriend or kids, or of the house you want to bid on, or the map of where you were on holiday, you’re sharing content,” says Tjora.

“This is the more pleasant or useful sharing side of using a phone and can sometimes be almost the opposite of taking a break from interacting.”

Maybe you have an email, an SMS or a document that you want to show your café partner. That belongs in this category, too. Or when you disagree about what that actor or musician’s name was, and a quick web search can tell you which one of you was right.

Content sharing in a café setting often raises new conversation topics and can enrich the interaction. Sharing is probably also the most socially accepted use of mobile phones.

Other uses

Of course, there are overlapping and grey areas too.

“For example, a mutual understanding can allow those who are meeting to take pictures of the coffee cup at the very beginning of the conversation and perhaps share the picture on social media for uninterested acquaintances. But then they put away their phones, either until a message appears, or perhaps even until the physical meeting comes to an end. If you go to a café to be social, the person with you in real life is the focus,” says Henriksen.

Sometimes there are also situations where café partners jointly agree to check this and that on their phones for a short while, but then put them away and concentrate on each other.

Others use their phone while the café partner is ordering at the counter or going to the toilet, simply to have something to do while the other person is away. This is almost like a kind of addiction, where we constantly have to be doing something and fill in all the breaks. The phone is immediately available, willing and able to satisfy this aversion to silence.

A conclusion, sort of

The smartphone is a tool for signalling interest or distance, but it can also enrich conversations and be used to share experiences with other people than only those who are physically present.

“The smartphone is a tool for signalling interest or distance, but it can also enrich conversations and be used to share experiences.”

“The study dispels the myth that everyone is constantly staring at their screens no matter the occasion, and shows that a form of courtesy with the phone has been established, at least in situations where the social aspect is prioritized,” says Tjora.

“The study dispels the myth that everyone is constantly staring at their screens no matter the occasion.”

“Whatever the reasons, one thing seems certain: smartphones have changed how we behave socially, for better or for worse. But maybe socializing has just become different in a way we need to become conscious of.

Reference: Henriksen, I.M .; Skaar, M .; Tjora, A. The Constitutive Practices of Public Smartphone Use. Societies 2020, 10 (4), 78; https://doi.org/10.3390/soc10040078

Provided by Norwegian Science Tech

Medicine

Gut Microbe May Promote Breast Cancers (Medicine)

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Short-term exposure to B. fragilis toxin leaves lasting impression in cells, increasing the risk for cancer.

A microbe found in the colon and commonly associated with the development of colitis and colon cancer also may play a role in the development of some breast cancers, according to new research from investigators with the Johns Hopkins Kimmel Cancer Center and its Bloomberg~Kimmel Institute for Cancer Immunotherapy. Breast tissue cells exposed to this toxin retain a long-term memory, increasing the risk for disease.

A microbe found in the colon may play a role in the development of some breast cancers. Credit: Adobe Stock

In a series of laboratory experiments, researchers discovered that when enterotoxigenic Bacteroides fragilis (ETBF) was introduced to the guts or breast ducts of mice, it always induced growth and metastatic progression of tumor cells. A description of the work is published in the January 6 issue of the journal Cancer Discovery.

While microbes are known to be present in body sites such as the gastrointestinal tract, nasal passages and skin, breast tissue was considered sterile until recently, says senior study author Dipali Sharma, Ph.D., a professor of oncology at Johns Hopkins Medicine.

The study is a first step to show the involvement of ETBF in breast cancer development, Sharma says. Additional studies are needed to clarify how ETBF moves throughout the body, whether ETBF can be a sole driver to directly trigger the transformation of breast cells in humans, and/or if other microbiota also have cancer-causing activity for breast tissue.

“Despite multiple established risk factors for breast cancer, such as age, genetic changes, radiation therapy and family history, a large number of breast cancers arise in women harboring none of these, indicating the need to look beyond,” Sharma says. “Our study suggests another risk factor, which is the microbiome. If your microbiome is perturbed, or if you harbor toxigenic microbes with oncogenic function, that could be considered an additional risk factor for breast cancer.”

Sharma and colleagues performed several experiments to study the role of ETBF. First, they performed a meta-analysis of clinical data looking at published studies comparing microbial composition among benign and malignant breast tumors and nipple aspirate fluids of breast cancer survivors and healthy volunteers. B. fragilis was consistently detected in all breast tissue samples as well as the nipple fluids of cancer survivors.

In the lab, the team gave the ETBF bacteria by mouth to a group of mice. First, it colonized the gut. Then, within three weeks, the mouse mammary tissue had observable changes usually present in ductal hyperplasia, a precancerous condition. In additional tests, investigators found that hyperplasia-like symptoms also appeared within two to three weeks of injecting ETBF bacteria directly to the teats of mice, and that cells exposed to the toxin always exhibited more rapid tumor progression and developed more aggressive tumors than cells not exposed to the toxin. Breast cells exposed to the toxin for 72 hours retained a memory of the toxin and were able to start cancer development and form metastatic lesions in different mouse models. Investigators also found the Notch1 and beta-catenin cell signaling pathways to be involved in promoting EBFT’s role in breast tissue.

In clinical studies, the investigators have started looking for microbiome changes among breast cancer patients to see how this impacts tumor progression and response to therapy. Meanwhile, Sharma says, “we definitely should try to maintain a healthy microbiome, including eating a healthy diet and exercising, and maintaining the correct body mass index.”

Down the road, screening for microbiome changes could be as simple as stool sample tests, said lead author Sheetal Parida, a postdoctoral fellow at Johns Hopkins Medicine. “This is just one indicator, and we think there will be multiple,” she said. “If we find additional bacteria responsible for cancer development, we can easily look at the stool and check for those. Women at high risk of developing breast cancer might have a high population of some of these.”

The work was supported by the National Cancer Institute (grants R01CA204555 and CA183804), the Breast Cancer Research Foundation, and Bloomberg Philanthropies.

Study co-authors were Shaoguang Wu, Sumit Siddarth, Guannan Wang, Nethaji Muniraj, Arumugam Nagalingam, Christina Hum, Panagiotis Mistriotis, Haiping Hao, C. Conover Talbot Jr., Konstantinos Konstantopoulos, Kathleen L. Gabrielson and Cynthia L. Sears.

Provided by Johns Hopkins Medicine

Medicine

New Evidence: Effects of Huntington’s Disease Mutation May begin in Childhood (Medicine)

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The neurodevelopmental hypothesis of Huntington’s disease (HD) suggests its origins are rooted in childhood when the mutant gene that causes HD begins to affect both brain and body growth and development, reports the Journal of Huntington’s Disease.

There is growing evidence to support the hypothesis that there is a neurodevelopmental component to the late-onset neurodegeneration occurring in the brain of huntingtin gene (HTT gene) mutation carriers, and that this increased susceptibility to brain cell death begins during childhood. Experts discuss the evidence that the HTT gene mutation affects brain and body growth based on a unique study of children at risk for HD, the Kids-HD study, in a review paper and accompanying research article published in the Journal of Huntington’s Disease.

Theories of the etiology of Huntington’s disease. © Journal of Huntington’s Disease.

The classic concept is that Huntington’s disease is caused by toxic mutant huntingtin (mHTT) acting over time on mature brain cells. However, there is growing evidence for an alternative theory in which mHTT has an effect on brain development and that this altered development plays a vital role in the later degenerative process. This theory is based on the notion that wild-type huntingtin (HTT) function plays a role in normal brain development.

“Although the gene was discovered in 1993, we still don’t have a good understanding of what causes HD – how does the mutant gene cause brain cells to become ‘sick’ then die?” noted lead investigator Peg C. Nopoulos, MD, Department of Psychiatry, Department of Pediatrics, and Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, IA, USA. “The neurodevelopmental hypothesis is a relatively new way of thinking about the disease and can help focus research efforts in a new direction. This review and the accompanying study are important in reshaping our ideas about how we view the nature and timing of preventive treatment for HD and the factors that contribute to disease.”

The neurodevelopmental hypothesis of HD posits that the disease-causing gene mutation affects development of a specific region or specific brain circuit. These cells are abnormal in their growth; however, they are compensated for early in life. Therefore, despite abnormal development, there are no overt symptoms. The abnormally developed cells remain in a “mutant steady state.” These cells are then vulnerable to dysfunction and degeneration later in life when they are subjected to stresses and strains, either normal (programmed synaptic elimination during puberty or through the aging process) or pathological (toxic effects of mHTT). In the end, the disease pathology results in neural degeneration with its accompanying cognitive and motor deficits.

The two papers focus on the most recent findings from Kids-HD, a unique brain imaging study of children aged six to 18 years old at risk for HD because they have a parent or grandparent with HD. The review discusses the effects of mHTT on brain development and the study evaluates the effect of mHTT on body development.

According to the authors, there is evidence in children as young as 6 who carry a mutation in the HTT gene, that production of mHTT alters the growth and development of the striatum and related circuitry. The gene contains a sequence of three DNA bases – cytosine-adenine-guanine (CAG) – repeated multiple times. The developmental changes appear to be influenced by the CAG repeat length and occur well before onset of symptoms of the disease. Deficits may then be compensated for by increased activity in other brain circuits, particularly those involving the cerebellum, and are manifest only when compensatory systems are no longer working.

The body development analysis used data from the 186 children in the Kids-HD study. Investigators applied simple measures of growth – height, weight, and the combined BMI measure – to compare changes in two groups – those who carried the CAG repeat expansion mutation in the HTT gene and those who did not.

Around puberty the study began to show an altered trajectory of growth in HTT gene mutation carriers. The pace at which their BMI increased slowed over time so that at by about 17 years old, that group had substantially lower BMI than the group without the gene mutation. Boys with the gene mutation tended to be taller than the control group, but with lower weight; girls with the gene mutation tended to be around the same height, but lower in weight.

Importantly, although the gene mutation carriers were roughly 30 years from the expected time of onset of the disease, the mutant HTT gene had already affected their growth and development. This work is important because it suggests that the mutation is altering the body even before the onset of neurological disease in midlife.

Gene therapy trials are currently underway to evaluate the effectiveness of drugs to slow disease progression in affected individuals, and future trials will ultimately aim to prevent disease onset by delivery of gene therapy to gene mutation carriers – those with mHTT, but no symptoms.

“Gene therapy trials are finally here. However, interfering with a gene responsible for brain development early in life must be done with an abundance of caution,” commented Dr. Nopoulos. “Understanding how mHTT affects brain development is vital in the context of planning disease prevention therapies.”

HD is a fatal genetic neurodegenerative disease that causes the progressive breakdown of nerve cells in the brain. An estimated 250,000 people in the United States are either diagnosed with, or at risk for, the disease. Symptoms include personality changes, mood swings and depression, forgetfulness and impaired judgment, unsteady gait, and involuntary movements (chorea). Every child of an HD parent has a 50% chance of inheriting the gene. Patients usually survive 10 – 20 years after diagnosis.

Reference: Tereshchenko, Alexander et al. ‘Developmental Trajectory of Height, Weight, and BMI in Children and Adolescents at Risk for Huntington’s Disease: Effect of mHTT on Growth’. 1 Jan. 2020 : 245 – 251. https://content.iospress.com/articles/journal-of-huntingtons-disease/jhd200407

Provided by IOS Press

Medicine

Liver Cancer Cells Manipulate Stromal Cells Involved in Fibrosis to Promote Tumor Growth (Medicine)

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Researchers led by Osaka University find that liver cancer cells cause local liver cells to produce a growth factor that enhances tumor growth.

Hepatocellular carcinoma (HCC), frequently seen in patients with liver cirrhosis caused by alcohol abuse or chronic viral hepatitis, is the most common form of liver cancer worldwide. As such, it is the third-most common cause of cancer-related death and has a notoriously poor prognosis. At present, surgery is the most effective treatment for HCC, but is only successful in the 10%-20% of cases where cancer cells have not spread beyond the liver.

The interaction between tumor cells and stellate cells in tumor microenvironment © Osaka University

Given the lack of treatment options for HCC, a group of researchers led by Osaka University decided to focus on specific cells and processes that occur in the area around liver tumors in the hope of finding a novel target for drug development.

The results of their study were published in a recent issue of Gastroenterology.

“Hepatic stellate cells (HSCs) are normal liver cells that play a role in the formation of scar tissue in response to liver damage,” explains co-author of the study Hayato Hikita. “High levels of activated HSCs have been reported in the tumor microenvironment and are associated with a poor prognosis in HCC patients. However, no one had examined the interaction between HSCs and cancer cells in the liver.”

The liver tumor growth was attenuated by knockout Atg7 or GDF15 in hepatic stellate cells. © Osaka University

When the researchers cultured liver cancer cells together with HSCs, they observed a significant increase in the number of cancer cells, suggesting that the HSCs somehow promoted cancer cell growth. Interestingly though, inhibition of autophagy (a cellular process primarily designed to remove damaged or unwanted cellular components) in the HSCs prevented the proliferation of cancer cells.

Using a mouse model of liver cancer and an analysis of gene expression, the researchers made the startling discovery that the cancer cells actually induced autophagy in the HSCs, which in turn caused the HSCs to secrete a protein called GDF15, which promoted tumor growth.

GDF15 positive hepatic stellate cells exist in human hepatocellular carcinoma. © Osaka University

“When we examined liver samples from HCC patients with and without tumors, we found that the tumor tissue samples had much higher levels of GDF15,” says senior author Tetsuo Takehara. “Most importantly though, when we then examined the association between GDF15 expression and clinical outcome, we found that patients with higher levels of GDF15 had a poorer prognosis than those with only low levels of GDF15 expression, which really highlighted the role of GDF15 in HCC progression.”

Building on the findings of this study, novel therapies targeting GDF15 expression by HSCs are an exciting new prospect for the treatment of HCC.

The article, “Hepatic stellate cells in hepatocellular carcinoma promote tumor growth via growth differentiation factor 15 production,” was published in Gastroenterology at DOI: https://doi.org/10.1053/j.gastro.2020.12.015

Provided by Osaka University

About Osaka University

Osaka University was founded in 1931 as one of the seven imperial universities of Japan and is now one of Japan’s leading comprehensive universities with a broad disciplinary spectrum. This strength is coupled with a singular drive for innovation that extends throughout the scientific process, from fundamental research to the creation of applied technology with positive economic impacts. Its commitment to innovation has been recognized in Japan and around the world, being named Japan’s most innovative university in 2015 (Reuters 2015 Top 100) and one of the most innovative institutions in the world in 2017 (Innovative Universities and the Nature Index Innovation 2017). Now, Osaka University is leveraging its role as a Designated National University Corporation selected by the Ministry of Education, Culture, Sports, Science and Technology to contribute to innovation for human welfare, sustainable development of society, and social transformation.

Website: https://resou.osaka-u.ac.jp/en

Quantum Mechanics

The World’s First Integrated Quantum Communication Network (Quantum)

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Chinese scientists have established the world’s first integrated quantum communication network, combining over 700 optical fibers on the ground with two ground-to-satellite links to achieve quantum key distribution over a total distance of 4,600 kilometers for users across the country. The team, led by Jianwei Pan, Yuao Chen, Chengzhi Peng from the University of Science and Technology of China in Hefei, reported in Nature their latest advances towards the global, practical application of such a network for future communications.

Chinese scientists have established the world’s first integrated quantum communication network, combining over 700 optical fibers on the ground with two ground-to-satellite links to achieve quantum key distribution over a total distance of 4,600 kilometers for users across the country. © University of science and technology of China

Unlike conventional encryption, quantum communication is considered unhackable and therefore the future of secure information transfer for banks, power grids and other sectors. The core of quantum communication is quantum key distribution (QKD), which uses the quantum states of particles–e.g. photons–to form a string of zeros and ones, while any eavesdropping between the sender and the receiver will change this string or key and be noticed immediately. So far, the most common QKD technology uses optical fibers for transmissions over several hundred kilometers, with high stability but considerable channel loss. Another major QKD technology uses the free space between satellites and ground stations for thousand-kilometer-level transmissions. In 2016, China launched the world’s first quantum communication satellite (QUESS, or Mozi/Micius) and achieved QKD with two ground stations which are 2,600 km apart. In 2017, an over 2,000-km-long optical fiber network was completed for QKD between Beijing and Shanghai.

Using trusted relays, the ground-based fiber network and the satellite-to-ground links were integrated to serve more than 150 industrial users across China, including state and local banks, municipal power grids, and e-government websites. “Our work shows that quantum communication technology is sufficiently mature for large-scale practical applications,” said Jianwei Pan, Professor of USTC. Similarly, a global quantum communication network can be established if national quantum networks from different countries are combined, and if universities, institutions and companies come together to standardize related protocols, hardware, etc., he added.

In the last couple of years, the team extensively tested and improved the performance of different parts of the integrated network. For instance, with an increased clock rate and more efficient QKD protocol, the satellite-to-ground QKD now has an average key generation rate of 47.8 kilobits per second, which is 40 times higher than the previous rate. The researchers have also pushed the record for ground-based QKD to beyond 500 km using a new technology called twin-field QKD (TF-QKD).

Next up, the team will further expand the network in China and with their international partners from Austria, Italy, Russia and Canada. They also aim to develop small-scale, cost-efficient QKD satellites and ground-based receivers, as well as medium and high earth orbit satellites to achieve all-time, ten-thousand-km-level QKD.

Their work was supported by the National Development and Reform Commission of China, the provincial/municipal government of Shandong, Anhui, and Shanghai, China Banking Regulatory Commission, the Chinese Academy of Sciences, the Ministry of Science and Technology of China, and the National Science Foundation of China.

Reference: http://dx.doi.org/10.1038/s41586-020-03093-8

Provided by University of Science and Technology of China

Earth Science

Will Global Warming Bring a Change in the Winds? Dust From the Deep Sea Provides a Clue (Earth Science)

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Westerlies moved poleward in the past, as they are doing now.

The westerlies–or westerly winds–play an important role in weather and climate both locally and on a global scale, by influencing precipitation patterns, impacting ocean circulation and steering tropical cyclones. So, finding a way to assess how they will change as the climate warms is crucial.

Image of a dust plume leaving China and crossing the Korean Peninsula and Japan. Researchers studied the dust deposited in ancient ocean sediments in order to understand how wind patterns in this area have shifted in the past. Their findings provide a better understanding of how the winds may change in the future. © SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

Typically, the westerlies blow from west to east across the planet’s middle latitudes. But scientists have noticed that over the last several decades, these winds are changing, migrating poleward. Research suggests this is because of climate change. But, scientists have been debating whether the poleward movement of the westerlies will continue as temperatures and atmospheric carbon dioxide (CO2) increase further under future warming scenarios. It’s been difficult to resolve this scientific question because our knowledge of the westerlies in past warm climates has until now been limited.

In a paper published January 6 in Nature, climate researchers from Columbia University’s Lamont-Doherty Earth Observatory describe a new method of tracking the ancient history of the westerly winds–a proxy for what we may experience in a future warming world. The lead author, Lamont graduate student Jordan Abell and his advisor, Gisela Winckler, developed a way to apply paleoclimatology–the study of past climate–to the question of the behavior of the westerly winds, and found evidence suggesting that atmospheric circulation patterns will change with climate warming.

The finding represents a breakthrough in our understanding of how the winds changed in the past, and how they may continue to change in the future.

Sediment cores like the one shown here, drilled from the bottom of the ocean, contain records of past climate conditions within their layers. Dust in cores collected by the research vessel JOIDES Resolution and stored at Texas A&M University helped to reveal changing patterns in the westerly winds. © Jordan Abell/Lamont-Doherty Earth Observatory

By using dust in ancient, deep sea sediments as an indirect tracer of wind, the researchers were able to reconstruct wind patterns that occurred three to five million years ago. Knowing that winds–in this case the westerlies–transport dust from desert regions to faraway locations, the authors examined cores from the North Pacific Ocean. This area is downwind from Eastern Asia, one of the largest dust sources today and a known dust-generating region for the past several million years. By measuring the dust in cores from two different sites thousands of kilometers apart, the researchers were able to map changes in dust, and in turn the westerly winds.

“We could immediately see the patterns. The data are so clear. Our work is consistent with modern observations, and suggests that wind patterns will change with climate warming,” said Abell.

They found that during the warm parts of the Pliocene (a period three to five million years ago, when the Earth was about two to four degrees Celsius warmer than today but had approximately the same concentration of CO2 in the air as we do now), the westerlies, globally, were located closer towards the poles than during the colder intervals afterwards.

The researchers found that during the warm parts of the Pliocene (3-5 million years ago), the westerlies were located closer to the poles. The image on the right shows how the westerlies moved toward the equator during colder intervals afterward. Recent observations indicate that as the planet warms due to climate change, the westerlies are once again shifting poleward. © Abell et al., Nature 2021

“By using the Pliocene as an analogue for modern global warming, it seems likely that the movement of the westerlies towards the poles observed in the modern era will continue with further human-induced warming,” explained Winckler.

The movement of these winds have huge implications for storm systems and precipitation patterns. And while this research does not indicate exactly where it will rain more or less, it confirms that the wind and precipitation patterns will change with climate warming.

“In the Earth history record, tracking down movements of wind and how they’ve changed, that’s been elusive because we didn’t have a tracer for it,” said Winckler. “Now we do.”

Provided by Earth Institute at Columbia University

Medicine

Statins May Protect the Heart from Chemotherapy Treatment of Early Breast Cancer (Medicine)

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Research Highlights:

  • Women who take statins, the common cholesterol-lowering medication, during chemotherapy with anthracyclines for early-stage breast cancer are half as likely to require emergency department visits or hospitalization for heart failure in the 5 years after chemotherapy.
  • There was also evidence that women taking statins may have a lower risk of heart failure after receiving the breast cancer medication trastuzumab.
  • Anthracyclines are an effective treatment for many women with breast cancer, however, it has an increased risk of heart muscle damage, which has limited their use.
  • Researchers say statin use should be encouraged in women starting potentially heart-toxic treatments for early-stage breast cancer if they already have indications to takethem for heart disease prevention. However, clinical trials are still needed to determine whether all women with breast cancer should be prescribed statins during chemotherapy that may harm the heart.

Statins, common cholesterol-lowering medications, may protect women’s hearts from damage caused during chemotherapy for early-stage breast cancer, according to new research published today in the Journal of the American Heart Association, an open access journal of the American Heart Association.

“Two types of cancer medications, anthracyclines and trastuzumab, are effective treatments for many women with breast cancer, however, the risk of heart muscle damage has limited their use, particularly in women who are at higher risk for heart problems because of their age or other medical issues,” said Husam Abdel-Qadir, M.D., Ph.D., lead author of the study, assistant professor of medicine at the University of Toronto’s Institute of Health Policy, Management and Evaluation, and a cardiologist at Women’s College Hospital and the Peter Munk Cardiac Centre, part of the University Health Network in Toronto.

“The mechanisms for these medications are essential to kill breast cancer cells, however, these processes can also damage the cells of the heart muscle, leading to weakening of the heart,” he said.

Previous small studies have suggested that women taking statins may have less heart muscle damage from these types of chemotherapy. The exact mechanisms of how statins protect against the cardiac cell damage remains unknown. It is believed that statins have antioxidative and anti-inflammatory actions.

For the current study, researchers used several administrative health databases in Ontario, Canada, to review the occurrence of heart failure in women ages 66 and older who received anthracyclines or trastuzumab for newly diagnosed early-stage breast cancer between 2007 and 2017. Each woman already taking statins was matched with a peer who was not taking statins as well as a variety of medical and social background factors. The two groups were compared to understand how many required hospitalizations or an emergency room visit for heart failure within the five years after chemotherapy. None had previously been diagnosed with heart failure.

Researchers found:

  • In the 666 pairs of women (median age 69) treated with anthracyclines, those taking statins were 55% less likely to be treated at the hospital for heart failure (1.2% vs. 2.9%).
  • In the 390 pairs of women (median age 71) treated with trastuzumab, those taking statins were 54% less likely to be treated at the hospital for heart failure (2.7% vs. 3.7%), a trend that did not reach statistical significance.

“Our findings support the idea that statins may be a potential intervention for preventing heart failure in patients receiving chemotherapy with anthracyclines and potentially trastuzumab,” Abdel-Qadir said.

This observational study found an association but cannot conclude that there is a cause-and-effect relationship between taking statins and a lower risk of heart failure.

“This study does not conclusively prove statins are protective,” Abdel-Qadir said. “However, this study builds on the body of evidence suggesting that they may have benefits. For women with breast cancer who meet established indications for taking a statin, they should ideally continue taking it throughout their chemotherapy treatment. Women who do not have an indication for a statin should ask their health care team if they can join a clinical trial studying the benefits of statins in protecting against heart muscle damage during chemotherapy. Otherwise, they should focus on measures to optimize their cardiovascular health before, during and after chemotherapy.”

Findings from this study in older women may not be generalizable to younger women or to those at low cardiovascular risk who do not meet current indications for a statin. Because the populations are similar in terms of demographics, these results from Canada are likely generalizable to women in the United States. Other limitations include that the study is a retrospective analysis that relied on administrative data, and the researchers could not account for potentially important factors that were not available, including the heart’s pumping ability and heart biomarkers.

Provided by American Heart Association

Astronomy

Accelerated Expansion of the Universe Is Due To Spacetime Vorticity (Cosmology /Astronomy)

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Babur Mirza and colleagues presented a general relativistic mechanism for accelerated cosmic expansion and the Hubble’s constant. They showed that spacetime vorticity coupled to the magnetic field density in galaxies causes the galaxies to recede from one another at a rate equal to the Hubble’s constant.

Accelerated expansion of the universe, as observed, for example, in the cosmological redshift measurements using type-Ia supernovae (SNe Ia) as standard candles, implies the need for an expansion energy effective at least up to the Mpc scale. A number of independent observations (including the SNe Ia redshift, the Hubble’s constant measurements, the cosmic microwave background (CMB), baryon acoustic oscillations, and various cosmological probes), have measured the contributions of matter and the cosmological constant to the energy density of the universe, providing an accurate measurement of the cosmic acceleration. However the amount of energy for this acceleration implies a hidden or dark form of energy which is approximately three times of the observed gravitational mass-energy density in the universe.

Within Einstein’s general theory of relativity, the observed expansion rate can be accounted for by including a cosmological constant, whose origin remains somewhat mysterious. In this context various mechanisms have been postulated, including new forms of hypothetical particles, or modifications of the Newtonian-Einsteinian law of gravitation at large distances, among others. However these theories are specialized in the sense that they fail to account for other observed features of the universe, such as the high degree of isotropy in CMB, or even some feature of the expansion, such as the correct value of the Hubble’s constant.

Now, Babur and colleagues in their work showed that the specific form of the cosmological constant, hence cosmic acceleration, which can be described by spacetime vorticity, is generated by galactic rotations. They showed that this vorticity coupled to the local (galactic) magnetic field provides the requisite push (repulsive energy) causing the individual galaxies to recede at an accelerated rate. They are therefore led to an oscillatory universe, where expansion and conversely contraction rate is determined by local spacetime vorticity, rather than global geometry (curvature) of the spacetime.

“To recapitulate we remark that, within the above model of the accelerated expansion of the universe, local spacetime vorticity and magnetic field energy generation within galaxies and galactic clusters act as the feedback mechanism for expansion. Thus, contrary to some recent suggestions that accelerated expansion must imply a violation of the law of conservation of energy, we see that energy conservation remains strictly valid not only locally but globally as well. The continued universal acceleration depends on the energy generation within galaxies, which in turn is determined by accretion rate in galactic nuclei.”, said Babur.

Friends, conversion of matter-energy density into the magnetic field energy under such conditions can only take a finite amount of time, hence the magnetic field driven acceleration cannot continue indefinitely for a finite total mass. Since the acceleration aB ∼ B’², where B’² is the magnetic energy density per unit volume, they saw that with the decreasing feedback magnetic field, universal acceleration after reaching an maximum will gradually decrease. With the decrease of Magnetic energy generation via accretion, a gradual deacceleration under gravitational attraction is likely to cause cosmic contraction. They therefore proposed that they have an oscillatory universe, where magneto-vorticity coupling rather than global spacetime curvature causes the expansion and contraction phases.

According to Babur, “A very high degree of entropy must have existed at the early stage of the universe, as inferred from the Planckian shape of the CMB radiation. This raises the paradox for other cosmological models, since entropy should decrease closer to the initial singularity (big bang). Our model implies that this must be so due to the expansion started before the cross-over R = Rs, where Rs is Schwarzschild singularity. Subsequently, as this expansion (inflation) stops, and matter formation starts, expansion under spacetime vorticity must now cause matter entropy to gradually increase with time. As deduced in our paper, this explains the high isotropy and the Planckian profile of the CMB spectrum, carrying the imprint of this initial inflation over R > Rs.”

Reference: Babur M. Mirza, “Can accelerated expansion of the universe be due to spacetime vorticity?”, Modern Physics Letters A, Vol. 33, No. 40, 1850240 (2018). https://www.worldscientific.com/doi/abs/10.1142/S0217732318502401 https://doi.org/10.1142/S0217732318502401

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