Hexbyte Glen Cove Sustainable optical fibers developed from methylcellulose thumbnail

Hexbyte Glen Cove Sustainable optical fibers developed from methylcellulose

Hexbyte Glen Cove

Schematic illustration of a light coupled optical fibre and photographs of methylcellulose-based optical fibers under ambient light and UV light. Credit: Ville Hynninen and Nonappa

Researchers from Tampere University and Aalto University have developed optical fibers from methylcellulose, a commonly used cellulose derivative. The finding opens new avenues to short-distance optical fibers using sustainable and environmentally benign fiber processing. The finding was published in the journal Small.

The state-of-the-art silica glass optical fibers can carry over tens of kilometers with very low optical loss and provide high-capacity communication networks. However, their brittleness, low stretchability and energy intensiveness make them less suitable for local short-range applications and devices such as automotive, digital home appliances, fabrics, laser surgery, endoscopy and implantable devices based on optical fibers. The sustainable solution to these may be found within biopolymer-based optical fibers.

“The wide availability of cellulosic raw materials provides an excellent opportunity to unravel the hidden potential of renewable materials for through sustainable fiber processing routes,” says Associate Professor Nonappa, whose research team at Tampere University is developing biopolymer-based optical fibers for short-distance applications.

Conventionally, the polymer or plastic optical fibers are used for short-distance applications, but their processing may involve relatively high temperatures and the use of hazardous chemical treatment.

“By using methylcellulose hydrogel, we have shown that optical fibers can be produced at room temperature using a simple extrusion method without any chemical crosslinkers. The resulting fibers are highly transparent, mechanically robust, flexible and show low optical loss,” Nonappa states.

Biopolymer-based optical fibers suitable for multifunctional sensors

In addition to pure light signal transmission, the methylcellulose optical fibers can be feasibly modified and functionalized.

“The allows straightforward addition of various molecules and nanoparticles without compromising the or light propagation abilities of the fibers making them suitable for multifunctional sensors,” says doctoral researcher Ville Hynninen, the first author of the paper.

For example, incorporating an extremely low mass fraction of protein-coated gold nanoclusters produced luminescent optical fibers, and acted also as a fiber-based toxic metal ion sensor.

Overall, the presented results and the abundance of cellulosic derivatives and raw materials encourage further research and optimization of cellulose-derived optical components and devices.

“Luminescent Gold Nanocluster-Methylcellulose Composite Optical Fibers with Low Attenuation Coefficient and High Photostability” was published in Small.



More information:
Ville Hynninen et al. Luminescent Gold Nanocluster‐Methylcellulose Composite Optical Fibers with Low Attenuation Coefficient and High Photostability, Small (2021). DOI: 10.1002/smll.202005205

Journal information:
Small


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Sustainable optical fibers developed from methylcellulose (2021, January 28)
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Hexbyte Glen Cove CERN's latest LS2 Report: Beams circulate in the PS Booster thumbnail

Hexbyte Glen Cove CERN’s latest LS2 Report: Beams circulate in the PS Booster

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A view of the PS Booster after its metamorphosis. Credit: CERN

If you follow CERN on social media, you probably saw back in December that the first beam had been injected into the PS Booster (PSB), thus connecting the machine for the first time to the new Linac4.

This is a crucial milestone for the LHC Injectors Upgrade (LIU) project and an extraordinary accomplishment for all the teams involved in the PSB metamorphosis. “We changed almost everything in the Booster during LS2; it is basically a new accelerator that we turned on at the beginning of December. It was a remarkable achievement and a testament to the excellent preparatory work done by all equipment groups to see that practically everything was working as expected,” says Bettina Mikulec, who leads the operations team for the PS Booster and Linac4.

But the commissioning of the booster is not as easy as turning on a TV. It is a lengthy and ongoing process. “In December, the brand-new state-of-the-art injection system was commissioned progressively and low-intensity beams were first guided to the very entrance of the accelerator, then injected into each one of the booster’s four rings,” explains Gian Piero Di Giovanni, LIU project leader for the PS Booster. “We managed to have circulating systematically for several hundred milliseconds, which is already a great success.”

The PS Booster is made up of four superposed synchrotron rings that are fed by Linac4. Depending on the beam schemes “requested” by the accelerators downstream, only some or all of the four rings receive beams.

Still, many settings have to be refined, and the operators must take ownership of their new machine. “The theoretical model developed for the upgraded booster now gives a better description of the machine. This allows us to be precise in our tuning, and to get the most out of the ,” adds Mikulec.

The booster currently receives beams from Linac4 at the energy of 160 MeV; its job is to accelerate them up to 2 GeV. “The ‘s new radiofrequency acceleration system is currently being commissioned. Once this crucial step is completed, we will be able to accelerate protons in the machine,” says Di Giovanni. This should happen in the coming weeks. In March, the first beams will then be extracted from the Booster into the PS. But that is another story.



Citation:
CERN’s latest LS2 Report: Beams circulate in the PS Booster (2021, January 28)
retrieved 28 January 2021
from https://phys.org/news/2021-01-cern-latest-ls2-circulate-ps.html

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Hexbyte Glen Cove Genome-editing tool TALEN outperforms CRISPR-Cas9 in tightly packed DNA

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Credit: CC0 Public Domain

Researchers used single-molecule imaging to compare the genome-editing tools CRISPR-Cas9 and TALEN. Their experiments revealed that TALEN is up to five times more efficient than CRISPR-Cas9 in parts of the genome, called heterochromatin, that are densely packed. Fragile X syndrome, sickle cell anemia, beta-thalassemia and other diseases are the result of genetic defects in the heterochromatin.

The researchers report their findings in the journal Nature Communications.

The study adds to the evidence that a broader selection of genome-editing tools is needed to target all parts of the genome, said Huimin Zhao, a professor of chemical and biomolecular engineering at the University of Illinois Urbana-Champaign who led the new research.

“CRISPR is a very powerful tool that led to a revolution in ,” Zhao said. “But it still has some limitations.”

CRISPR is a bacterial molecule that detects invading viruses. It can carry one of several enzymes, such as Cas-9, that allow it to cut viral genomes at specific sites. TALEN also scans DNA to find and target specific genes. Both CRISPR and TALEN can be engineered to target to fight disease, improve crop plant characteristics or for other applications.

Zhao and his colleagues used single-molecule fluorescence microscopy to directly observe how the two genome-editing tools performed in living mammalian cells. Fluorescent-labeled tags enabled the researchers to measure how long it took CRISPR and TALEN to move along the DNA and to detect and cut target sites.

“We found that CRISPR works better in the less-tightly wound regions of the genome, but TALEN can access those genes in the heterochromatin region better than CRISPR,” Zhao said. “We also saw that TALEN can have higher editing efficiency than CRISPR. It can cut the DNA and then make changes more efficiently than CRISPR.”

TALEN was as much as five times more efficient than CRISPR in multiple experiments.

The findings will lead to improved approaches for targeting various parts of the genome, Zhao said.

“Either we can use TALEN for certain applications, or we could try to make CRISPR work better in the heterochromatin,” he said.



More information:
“TALEN outperforms Cas9 in editing heterochromatin target sites” Nature Communications (2021). DOI: 10.1038/s41467-020-20672-5

Citation:
Genome-editing tool TALEN outperforms CRISPR-Cas9 in tightly packed DNA (2021, January 27)
retrieved 27 January 2021
from https://phys.org/news/2021-01-genome-editing-tool-talen-outperforms-crispr-cas9.html

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Hexbyte Glen Cove Carbon-chomping soil bacteria may pose hidden climate risk

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Soil on a chip experiments conducted by Princeton researchers mimic the interactions between soils, carbon compounds and soil bacteria, producing new evidence that large carbon molecules can potentially escape the soil much faster than previously thought. In this microscopy image, soil bacteria (red) grow around aggregates of glucose (green) that stick to pores in a transparent synthetic clay. Credit: Judy Q. Yang

Much of the earth’s carbon is trapped in soil, and scientists have assumed that potential climate-warming compounds would safely stay there for centuries. But new research from Princeton University shows that carbon molecules can potentially escape the soil much faster than previously thought. The findings suggest a key role for some types of soil bacteria, which can produce enzymes that break down large carbon-based molecules and allow carbon dioxide to escape into the air.

More carbon is stored in soil than in all the planet’s plants and atmosphere combined, and soil absorbs about 20% of human-generated carbon emissions. Yet, factors that affect carbon storage and release from soil have been challenging to study, placing limits on the relevance of soil carbon models for predicting climate change. The new results help explain growing evidence that large carbon molecules can be released from soil more quickly than is assumed in common models.

“We provided a new insight, which is the surprising role of biology and its linkage to whether carbon remains stored” in soil, said coauthor Howard Stone, the Donald R. Dixon ’69 and Elizabeth W. Dixon Professor of Mechanical and Aerospace Engineering.

In a paper published Jan. 27 in Nature Communications, the researchers, led by former postdoctoral fellow Judy Q. Yang, developed “soil on a chip” experiments to mimic the interactions between soils, carbon compounds and soil bacteria. They used a synthetic, transparent clay as a stand-in for clay components of soil, which play the largest role in absorbing carbon-containing molecules.

The “chip” was a modified microscope slide, or a microfluidic device, containing silicone-walled channels half a centimeter long and several times the width of a human hair (about 400 micrometers). Inlet and outlet tubes at each end of the channels allowed the researchers to inject the synthetic clay solution, followed by suspensions containing carbon molecules, bacteria or enzymes.

After coating the channels with the see-through clay, the researchers added fluorescently labeled sugar molecules to simulate carbon-containing nutrients that leak from plants’ roots, particularly during rainfall. The experiments enabled the researchers to directly observe carbon compounds’ locations within the clay and their movements in response to fluid flow in real time.

Both small and large sugar-based molecules stuck to the synthetic clay as they flowed through the device. Consistent with current models, were easily dislodged, while larger ones remained trapped in the clay.

When the researchers added Pseudomonas aeruginosa, a common soil bacterium, to the soil-on-a-chip device, the bacteria could not reach the nutrients lodged within the clay’s small pores. However, the enzyme dextranase, which represents enzymes released by certain soil bacteria, could break down the nutrients within the synthetic clay and make smaller sugar molecules available to fuel bacterial metabolism. In the environment, this could lead large amounts of CO2 to be released from soil into the atmosphere.

The researchers coated this microfluidic device with see-through clay, then added fluorescently labeled sugar molecules and visualized the sorption and release of carbon from clay under a microscope. Credit: Judy Q. Yang

Researchers have often assumed that larger carbon compounds are protected from release once they stick to clay surfaces, resulting in long-term carbon storage. Some recent field studies have shown that these compounds can detach from clay, but the reason for this has been mysterious, said lead author Yang, who conducted the research as a postdoctoral fellow at Princeton and is now an assistant professor at the University of Minnesota.

“This is a very important phenomenon, because it’s suggesting that the carbon sequestered in the soil can be released [and play a role in] future climate change,” said Yang. “We are providing direct evidence of how this carbon can be released—we found out that the enzymes produced by bacteria play an important role, but this has often been ignored by climate modeling studies” that assume clay protects carbon in soils for thousands of years.

The study sprang from conversations between Stone and coauthor Ian Bourg, an assistant professor of civil and environmental engineering and the High Meadows Environmental Institute. Stone’s lab has used microfluidic devices to study the properties of synthetic fibers and bacterial biofilms, while Bourg has expertise in the surface geochemistry of clay minerals—which are thought to contribute most to soil carbon storage due to their fine-scale structure and surface charges.

Stone, Bourg and their colleagues realized there was a need to experimentally test some of the assumptions in widely used models of carbon storage. Yang joined Stone’s group to lead the research, and also collaborated with Xinning Zhang, an assistant professor of geosciences and the High Meadows Environmental Institute who investigates the metabolisms of bacteria and their interactions with the soil environment.

Jinyun Tang, a research scientist in the climate sciences department at Lawrence Berkeley National Laboratory, noted that in recent years he and others have observed the degradation of large carbon molecules in soils and hypothesized that it was mediated by biologically produced enzymes.

The Princeton team’s observations “provide a very strong support to our hypothesis,” said Tang, who was not involved in the study. He added that the study’s technique could also be used to explore such questions as “Will the reversible interaction between small-size carbon molecules and particles induce carbon starvation to the microbes and contribute to carbon stabilization? And how do such interactions help maintain microbial diversity in soil? It is a very exciting start.”

Future studies will test whether bacteria in the model system can release their own enzymes to degrade large carbon molecules and use them for energy, releasing CO2 in the process.

While the carbon stabilization Tang described is possible, the newly discovered phenomenon could also have the opposite effect, contributing to a positive feedback loop with the potential to exacerbate the pace of climate change, the study’s authors said. Other experiments have shown a “priming” effect, in which increases in small sugar in soil lead to release of , which may in turn cause bacteria to grow more quickly and release more enzymes to further break down larger , leading to still further increases in bacterial activity.



More information:
Nature Communications (2021). DOI: 10.1038/s41467-020-20798-6

Citation:
Carbon-chomping soil bacteria may pose hidden climate risk (2021, January 27)
retrieved 27 January 2021
from https://phys.org/news/2021-01-carbon-chomping-soil-bacteria-pose-hidden.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes on