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Comment by Dr. Krishna Kumari Challa on December 26, 2022 at 8:58am

Researchers use quantum mechanics to see objects without looking at them

We see the world around us because light is being absorbed by specialized cells in our retina. But can vision happen without any absorption at all—without even a single particle of light? Surprisingly, the answer is yes.

Imagine that you have a camera cartridge that might contain a roll of photographic film. The roll is so sensitive that coming into contact with even a single photon would destroy it. With our everyday classical means there is no way  to know whether there's film in the cartridge, but in the quantum world it can be done. Anton Zeilinger, one of the winners of the 2022 Nobel Prize in Physics, was the first to experimentally implement the idea of an interaction-free experiment using optics.

Now, in a study exploring the connection between the quantum and classical worlds,  researchers have discovered a new and much more effective way to carry out interaction-free experiments. They used transmon devices—superconducting circuits that are relatively large but still show quantum behavior—to detect the presence of microwave pulses generated by classical instruments. Their research was recently published in Nature Communications.

Quantum coherence refers to the possibility that an object can occupy two different states at the same time—something that quantum physics allows for. However, quantum coherence is delicate and easily collapses, so it wasn't immediately obvious that the new protocol would work. To the research  team's pleasant surprise, the first runs of the experiment showed a marked increase in detection efficiency. They went back to the drawing board several times, ran theoretical models confirming their results, and double-checked everything. The effect was definitely there. They also also demonstrated that even very low-power microwave pulses can be detected efficiently using their protocol.

The experiment also showed a new way in which quantum devices can achieve results that are impossible for classical devices—a phenomenon known as quantum advantage. Researchers generally think that achieving quantum advantage will require quantum computers with many qubits, but this experiment demonstrated genuine quantum advantage using a relatively simpler setup.

Shruti Dogra et al, Coherent interaction-free detection of microwave pulses with a superconducting circuit, Nature Communications (2022). DOI: 10.1038/s41467-022-35049-z

Comment by Dr. Krishna Kumari Challa on December 24, 2022 at 1:24pm

Mitochondrial transplant shows promise In a world first, six children with rare disorders caused by deletions in the genomes of their mitochrondria — the cellular compartments essential for energy generation — have been successfully treated with donor mitochondria from their m.... Doctors transferred healthy mitochondria into the children’s haematopoietic stem cells, which give rise to the body’s blood cells. After the treatment, tests showed that some of the children were stronger and had reached healthier weights, and caregivers said they spent more time awake and in play. “These are very soft measures that are hard to report, but we did see major improvements to the quality of life in almost all of these children,” says paediatric haematologist Elad Jacoby, who led the study. A clinical trial of the approach, known as mitochondrial augmentation therapy, is expected to start next year. https://www.science.org/doi/10.1126/scitranslmed.abo3724

Comment by Dr. Krishna Kumari Challa on December 24, 2022 at 1:14pm

Identifying pathways to slow cardiac aging

Cardiovascular disease is the leading cause of death worldwide, and is caused in part by age-related cardiac structural dysfunction. A team of bioengineers published a paper in Nature Aging on Dec. 22 that helps advance our understanding of how hearts age, and sheds light on a possible pathway to slow cardiac aging.

The researchers used fruit flies to show that Lamin C, a protein responsible for maintaining the structural integrity of heart cells' nuclei, declines as flies age. This study uncovered that Lamin decline is responsible for the age-induced structural remodeling in fruit fly hearts, and it could be a potential target to slow down, or even help reverse, cardiac aging in humans.

The team then quantified this change by segmenting and measuring nuclear stiffness with atomic force microscopy. This is when they discovered that cardiomyocyte nuclei stiffen during natural aging; after running a genetic anlysis, the researchers found that the expression of nuclear lamins decreases as flies age.

The team was able to verify that these results also applied to mice and primates. This indicates that a role for Lamins may apply to human heart aging as well, which could have tremendous therapeutic value, as targeting lamin-stimulating pathways could potentially help avoid this cardiac aging-related mechanical change.

Natalie J. Kirkland et al, Age-dependent Lamin changes induce cardiac dysfunction via dysregulation of cardiac transcriptional programs, Nature Aging (2022). DOI: 10.1038/s43587-022-00323-8

Comment by Dr. Krishna Kumari Challa on December 23, 2022 at 1:53pm

Male and Female Stem Cells Derived from One Donor in Scientific First

Studying otherwise identical XY, XX, X0, and XXY pluripotent stem cells will allow researchers to investigate sex-based differences in greater depth.

Scientists have developed a new line of stem cells—all derived from the same person—that can be used to study sex differences without the confounds of interpersonal genetic differences.

Human induced pluripotent stem cells (hiPSCs), which are cells taken from a person that are then reprogrammed to abandon their current roles and return to a stem cell–like state, have become valuable tools not only for therapeutic purposes but also for probing the genetic mechanisms underlying cell behavior and disease. However, findings drawn from stem cell studies may not be broadly applicable, as the fact that all cells in a given line share the same genetic sequence makes it difficult to generalize discoveries, especially when it comes to investigating potential sex differences.

That’s why a team of scientists set out to create a new platform for studying genetic sex differences. 

To develop such a model, the team obtained cells from a repository that had been taken from someone with an unusual case of Klinefelter syndrome, a rare genetic condition that affects roughly 1 in 500 boys in which they’re born with an extra copy of the X chromosome, resulting in an XXY genetic makeup. What made this person even more unusual—and ideal for Reubinoff’s vision—is that, in addition to the 47XXY cells characteristic of the condition, they also had a large number of 46XY cells, a phenomenon known as a mosaic phenotype. As the study, published on November 24 in Stem Cell Reports, describes, the variety of cells taken from the Klinefelter patient allowed the team to generate 46XX, 46XY, 45X0, and 47XXY hiPSCs that are otherwise genetically identical. This means that any observable differences among them—related, for example, to disease risk factors or response to a pharmaceutical—can almost definitely be attributed to genetic sex differences.

When you study individuals, and you compare males to females and you find differences, you cannot differentiate whether they stem from the chromosomal differences or hormonal differences. This model is unique because it allows you to differentiate between chromosomal effects and hormonal effects.

https://www.cell.com/stem-cell-reports/fulltext/S2213-6711(22)00513-6?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2213671122005136%3Fshowall%3Dtrue#%20

https://www.the-scientist.com/news-opinion/male-and-female-stem-cel...

Comment by Dr. Krishna Kumari Challa on December 23, 2022 at 12:47pm

Are elephants afraid of mice?

Mythbusters explore the myth of whether elephants are afraid of mice.

Comment by Dr. Krishna Kumari Challa on December 23, 2022 at 12:25pm

Microplastics deposited on the seafloor have tripled in 20 years

The total amount of microplastics deposited on the bottom of oceans has tripled in the past two decades with a progression that corresponds to the type and volume of consumption of plastic products by society.

This is the main conclusion of a recent study.

Despite the seafloor being considered the final sink for microplastics floating on the sea surface, the historical evolution of this pollution source in the sediment compartment, and particularly the sequestration and burial rate of smaller microplastics on the ocean floor, is unknown. This new study, published in the journal Environmental Science and Technology, shows that microplastics are retained unaltered in marine sediments, and that the microplastic mass sequestered in the seafloor mimics the global plastic production from 1965 to 2016.

Specifically, the results show that, since 2000, the amount of plastic particles deposited on the seafloor has tripled and that, far from decreasing, the accumulation has not stopped growing mimicking the production and global use of these materials.

Researchers explains that the sediments analyzed have remained unaltered on the seafloor since they were deposited decades ago. This has allowed them to see how, since the 1980s, but especially in the past two decades, the accumulation of polyethylene and polypropylene particles from packaging, bottles and food films has increased, as well as polyester from synthetic fibers in clothing fabrics.

The amount of these three types of particles reaches 1.5mg per kilogram of sediment collected, with polypropylene being the most abundant, followed by polyethylene and polyester. Despite awareness campaigns  on the need to reduce single-use plastic, data from annual marine sediment records show that we are still far from achieving this. Policies at the global level in this regard could contribute to improving this serious problem.

The degradation status of the buried particles was investigated, and it was found that, once trapped in the seafloor, they no longer degrade, either due to lack of erosion, oxygen, or light.

Laura Simon-Sánchez et al, Can a Sediment Core Reveal the Plastic Age? Microplastic Preservation in a Coastal Sedimentary Record, Environmental Science & Technology (2022). DOI: 10.1021/acs.est.2c04264

Comment by Dr. Krishna Kumari Challa on December 23, 2022 at 11:59am

Meta-optics: The disruptive technology you didn't see coming

Robots and autonomous cars will have eyes that see much more than the human eye is capable of, a review of the growing field of meta-optics has found.

Meta-optics is advancing science and technology far beyond the 3,000-year-old optical paradigm that we rely on for the visual human-machine interface, such as through cameras in our mobile phones, the lenses in microscopes, drones, and telescopes. Optical components are the technology bottleneck that meta-optics aims to transform, bringing the stuff of science-fiction stories into everyday devices. The field, which blossomed after the early 2000s thanks to the conceptualization of a material with negative refractive index that could form a perfect lens, has grown rapidly in the last five years and now sees around 3000 publications a year. This accelerating volume of research is impossible for scientists and technologists to navigate, which prompted Nature Photonics to commission a review from leaders in meta-optics research.

They found the field was on the verge of industrial disruption.

The biggest driver for the meta-optics field comes from integrating meta-optical elements and devices into optical systems, offering consumer optoelectronics applications. Importantly, meta-optical systems enable novel applications not conceivable before, adding to so-called Industry 4.0. Such applications include the Internet of Things, autonomous cars, wearable devices, augmented reality and remote sensing. The importance of the technology is shown by the large-scale investment from big industry players such as Apple, Google, and Samsung, who have been hiring graduates and investing in the field, especially to develop vision applications.

But the authors note that beyond vision, the non-traditional characteristics of meta-optics could also be used for light sails, LiFi and thermal management. These characteristics come from meta-optics' use of surfaces patterned with regular nanoscale structures, in contrast with the traditional optics of mirrors and lenses. The result is miniature components that scatter and manipulate light in ways that would have astounded Isaac Newton. The first commercial components using these properties are already on the market, with companies such as Metalenz, NILT technologies and Meta Materials Inc delivering flat metalenses, polarization imaging, microscopy and biosensing. These devices also enable access to properties of light that the human eye cannot detect—polarization and phase, for example, and even can be used to engineer, manipulate and quantum states of light, that could be employed for quantum imaging, sensing and communications.

Dragomir Neshev, Enabling smart vision with metasurfaces, Nature Photonics (2022). DOI: 10.1038/s41566-022-01126-4. www.nature.com/articles/s41566-022-01126-4

https://phys.org/news/2022-12-meta-optics-disruptive-technology-did...

Comment by Dr. Krishna Kumari Challa on December 23, 2022 at 11:20am

Researchers use 3D bioprinting to create eye tissue

Scientists used patient stem cells and 3D bioprinting to produce eye tissue that will advance understanding of the mechanisms of blinding diseases. The research team from the National Eye Institute (NEI), part of the National Institutes of Health, printed a combination of cells that form the outer blood-retina barrier—eye tissue that supports the retina's light-sensing photoreceptors. The technique provides a theoretically unlimited supply of patient-derived tissue to study degenerative retinal diseases such as age-related macular degeneration (AMD).

We know that AMD starts in the outer blood-retina barrier. However, mechanisms of AMD initiation and progression to advanced dry and wet stages remain poorly understood due to the lack of physiologically relevant human models.

The outer blood-retina barrier consists of the retinal pigment epithelium (RPE), separated by Bruch's membrane from the blood-vessel rich choriocapillaris. Bruch's membrane regulates the exchange of nutrients and waste between the choriocapillaris and the RPE. In AMD, lipoprotein deposits called drusen form outside Bruch's membrane, impeding its function. Over time, the RPE break down leading to photoreceptor degeneration and vision loss.

Researchers combined three immature choroidal cell types in a hydrogel: pericytes and endothelial cells, which are key components of capillaries; and fibroblasts, which give tissues structure. The scientists then printed the gel on a biodegradable scaffold. Within days, the cells began to mature into a dense capillary network.

On day nine, the scientists seeded retinal pigment epithelial cells on the flip side of the scaffold. The printed tissue reached full maturity on day 42. Tissue analyses and genetic and functional testing showed that the printed tissue looked and behaved similarly to native outer blood-retina barrier. Under induced stress, printed tissue exhibited patterns of early AMD such as drusen deposits underneath the RPE and progression to late dry stage AMD, where tissue degradation was observed. Low oxygen induced wet AMD-like appearance, with hyperproliferation of choroidal vessels that migrated into the sub-RPE zone. Anti-VEGF drugs, used to treat AMD suppressed this vessel overgrowth and migration and restored tissue morphology.

Researchers  are using printed blood-retina barrier models to study AMD, and they are experimenting with adding additional cell types to the printing process, such as immune cells, to better recapitulate native tissue.

Kapil Bharti, Bioprinted 3D outer retina barrier uncovers RPE-dependent choroidal phenotype in advanced macular degeneration, Nature Methods (2022). DOI: 10.1038/s41592-022-01701-1. www.nature.com/articles/s41592-022-01701-1

Comment by Dr. Krishna Kumari Challa on December 22, 2022 at 12:11pm

The physical intelligence of ant and robot collectives

Researchers took inspiration from ants to design a team of relatively simple robots that can work collectively to perform complex tasks using only a few basic parameters.

https://techxplore.com/news/2022-12-physical-intelligence-ants-robo...

Comment by Dr. Krishna Kumari Challa on December 22, 2022 at 11:35am

Study finds birds build hanging-nests to protect offspring from nest invaders

A new study has found that birds build hanging-nests, particularly those with extended entrance tunnels, to help protect offspring against nest invaders like snakes and parasitic cuckoos.

Researchers examined the relationship between nest design and the length of time offspring spend in the nest before fledging across species of weaverbirds and icterids, two bird families renowned for their complex woven nests. They found that species building the most elaborate nests, particularly those with long entrance tunnels, produce offspring with longer developmental periods.

Nests with longer entrance tunnels are more effective at hindering access by nest invaders than shorter tunnels and thereby limits the exposure of developing offspring to nest invaders.

Researchers suggest that the complex structural features in these nests do indeed play a role in protecting offspring from predators and brood parasites. They find the consistency of these findings "striking" given that highly elaborate nests have evolved independently in the weaverbirds and icterids.

Sally Street et al, Convergent evolution of elaborate nests as structural defences in birds, Proceedings of the Royal Society B: Biological Sciences (2022). DOI: 10.1098/rspb.2022.1734. royalsocietypublishing.org/doi … .1098/rspb.2022.1734

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