Partial solar eclipse from Iceland to India on Tuesday

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A partial solar eclipse in Iraq in 2019. Tuesday’s eclipse is not expected to darken the sky.

A partial solar eclipse will be visible across a swathe of the Northern Hemisphere on Tuesday, with amateur astronomers warned to take care watching the rare phenomenon.

The eclipse will start at 0858 GMT in Iceland and end off the coast of India at 1302 GMT, crossing Europe, North Africa and the Middle East on its way, according to the IMCCE institute of France’s Paris Observatory.

Solar eclipses occur when the Moon passes between the Sun and Earth, casting its shadow down onto our planet.

A total solar eclipse happens when the Moon completely blocks the Sun’s disk, momentarily plunging a portion of the Earth into complete darkness.

However Tuesday’s eclipse is only partial, and the “Moon’s shadow will not touch the surface of the Earth at any point,” the Paris Observatory said in a statement.

The Moon will cover a maximum of 82 percent of the Sun over Kazakhstan, but it will not be enough darken the daylight, Paris Observatory Florent Deleflie said.

“To start getting the sense of darkness in the sky, to perceive a kind of cold light, the Sun needs to be at least 95 percent obscured,” Deleflie told AFP.

Those hoping to watch the eclipse should not look at the Sun directly, even through clouds, to avoid eye damage, according to experts. Protective eyewear should be worn instead.

“We will see that a small piece of the Sun is missing. It won’t be spectacular, but it’s always an event for amateur astronomers—and it can make for beautiful photos,” Deleflie said.

It will be the 16th of the century, and the second of this year.

The next total solar eclipse will cross North America on April 8, 2024, according to NASA.

© 2022 AFP

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New data transmission record set using a single laser and a single optical chip

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Credit: Unsplash/CC0 Public Domain

An international group of researchers from Technical University of Denmark (DTU) and Chalmers University of Technology in Gothenburg, Sweden have achieved dizzying data transmission speeds and are the first in the world to transmit more than 1 petabit per second (Pbit/s) using only a single laser and a single optical chip.

1 petabit corresponds to 1 million gigabits.

In the experiment, the researchers succeeded in transmitting 1.8 Pbit/s, which corresponds to twice the total global Internet traffic. And only carried by the light from one optical source. The light source is a custom-designed optical chip, which can use the light from a single infrared to create a rainbow spectrum of many colors, i.e., many frequencies. Thus, the one frequency (color) of a single laser can be multiplied into hundreds of frequencies (colors) in a single chip.

All the colors are fixed at a specific frequency distance from each other—just like the teeth on a comb—which is why it is called a frequency comb. Each color (or frequency) can then be isolated and used to imprint data. The frequencies can then be reassembled and sent over an optical fiber, thus transmitting data. Even a huge volume of data, as the researchers have discovered.

One single laser can replace thousands

The experimental demonstration showed that a single chip could easily carry 1.8 Pbit/s, which—with contemporary state-of-the-art commercial equipment—would otherwise require more than 1,000 lasers.

Victor Torres Company, professor at Chalmers University of Technology, is head of the research group that has developed and manufactured the chip.

“What is special about this chip is that it produces a frequency comb with ideal characteristics for fiber-optical communications—it has high optical power and covers a broad bandwidth within the spectral region that is interesting for advanced optical communications,” says Victor Torres Company.

Interestingly enough, the chip was not optimized for this particular application.

“In fact, some of the characteristic parameters were achieved by coincidence and not by design,” says Victor Torres Company. “However, with efforts in my team, we are now capable to reverse engineer the process and achieve with high reproducibility microcombs for target applications in telecommunications.”

Enormous potential for scaling

In addition, the researchers created a computational model to examine theoretically the fundamental potential for data transmission with a single chip identical to the one used in the experiment. The calculations showed enormous potential for scaling up the solution.

Professor Leif Katsuo Oxenløwe, Head of the Center of Excellence for Silicon Photonics for Optical Communications (SPOC) at DTU, says:

“Our calculations show that—with the single chip made by Chalmers University of Technology, and a single laser—we will be able to transmit up to 100 Pbit/s. The reason for this is that our solution is scalable—both in terms of creating many frequencies and in terms of splitting the into many spatial copies and then optically amplifying them, and using them as parallel sources with which we can transmit data. Although the comb copies must be amplified, we do not lose the qualities of the comb, which we utilize for spectrally efficient .”

This is how you pack light with data

Packing light with data is known as modulation. Here, the wave properties of light are utilized such as:

  • Amplitude (the height/strength of the waves)
  • Phase (the “rhythm” of the waves, where it is possible to make a shift so that a wave arrives either a little earlier or a little later than expected)
  • Polarization (the directions in which the waves spread).

By changing these properties, you create signals. The signals can be translated into either ones or zeros—and thus utilized as data signals.

Reduces Internet power consumption

The researchers’ solution bodes well for the future power consumption of the Internet.

“In other words, our solution provides a potential for replacing hundreds of thousands of the lasers located at Internet hubs and data centers, all of which guzzle power and generate heat. We have an opportunity to contribute to achieving an Internet that leaves a smaller climate footprint,” says Leif Katsuo Oxenløwe.

Even though the researchers have broken the petabit barrier for a single laser source and a single chip in their demonstration, there is still some development work ahead before the solution can be implemented in our current communication systems, according to Leif Katsuo Oxenløwe.

“All over the world, work is being done to integrate the laser source in the optical chip, and we’re working on that as well. The more components we can integrate in the chip, the more efficient the whole transmitter will be, i.e., laser, comb-creating chip, data modulators, and any amplifier elements. It will be an extremely efficient optical transmitter of data signals,” says Leif Katsuo Oxenløwe.

The research is published in Nature Photonics.

More information:
A. A. Jørgensen et al, Petabit-per-second data transmission using a chip-scale microcomb ring resonator source, Nature Photonics (2022). DOI: 10.1038/s41566-022-01082-z

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Fully mature hair follicles grown in cultures

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A representative long sprouting hair follicle generated from hair follicloids after an extended period of culture. Credit: Yokohama National University

A team of researchers from Japan studying the processes of hair follicle growth and hair pigmentation has successfully generated hair follicles in cultures. Their in vitro hair follicle model adds to the understanding of hair follicle development which could contribute to development of useful applications in treating hair loss disorders, animal testing, and drug screenings.

Their findings were published in Science Advances on October 21.

As an embryo develops, interactions occur between the outer layer of skin called the epidermal layer and the connective tissue called mesenchyme. These interactions work kind of like a messenger system to trigger morphogenesis. Morphogenesis is the process in an organism where cells are organized into tissues and organs.

During the last several decades, scientists have explored the crucial mechanisms related to hair follicle development using animal models. Because fully understanding these mechanisms for hair follicle development remains challenging, hair follicle morphogenesis has not been successfully reproduced in a laboratory culture dish.

More recently cultures have received widespread attention. Organoids are tiny, simple versions of an organ—scientists produce and use them to study tissue and organ development and pathology in a laboratory culture dish. “Organoids were a promising tool to elucidate the mechanisms in hair follicle morphogenesis in vitro,” said Tatsuto Kageyama, an assistant professor with the faculty of engineering at Yokohama National University.

The research team fabricated hair follicle organoids by controlling the structure generated from the two types of embryonic cells using quite a low concentration of extracellular matrices. The is the framework in the body that provides structure for cells and tissue. The extracellular matrices adjusted the spacing between the two types of embryonic cells from a dumbbell-shape to core-shell configuration. Newly formed hair follicles with typical features emerged in core-shell-shape groups. These core-shell-shape groups increase the between two cell regions to enhance the mechanisms that contribute to hair follicle growth.

The organoid culture system the research team developed generated hair follicles and hair shafts with almost 100 percent efficiency. The hair follicle organoids produced fully mature hair follicles with long hair shafts (approximately 3 mm length on 23 days of culture). As this growth occurred, the researchers could monitor hair follicle morphogenesis and hair pigmentation in vitro and understand the signaling pathways involved in the processes.

The researchers examined the feasibility of hair follicle organoids for drug screening and . Then they added a melanocyte-stimulating drug, that plays a key role in producing hair color pigmentation, into the culture medium. With the addition of this drug, the researchers significantly improved the hair pigmentation of the hair-like fibers. Furthermore, by transplanting the hair follicle organoids, they achieved efficient hair follicle regeneration with repeating hair cycles. They believe the in vitro hair follicle model could prove valuable for better understanding of hair follicle induction, for evaluating hair pigmentation and hair growth drugs, and for regenerating hair follicles.

The researchers’ findings could also prove to be relevant to other and contribute to the understanding of how physiological and pathological processes develop. Looking ahead to future research, the team plans to optimize their organoid culture system with . “Our next step is to use cells from human origin, and apply for drug development and regenerative medicine,” said Junji Fukuda, a professor with the faculty of engineering at Yokohama National University.

Their future research could eventually open up new research avenues for the development of fresh treatment strategies for hair loss disorders, such as androgenic alopecia that is common in both men and women.

More information:
Tatsuto Kageyama et al, Reprogramming of three-dimensional microenvironments for in vitro hair follicle induction, Science Advances (2022). DOI: 10.1126/sciadv.add4603.

Provided by
Yokohama National University

Fully mature hair follicles grown in cultures (2022, October 21)
retrieved 22 October 2022

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