Hexbyte Glen Cove Discovered: An easier way to create ‘flexible diamonds’

Hexbyte Glen Cove

Artist’s conception showing how guided diamond nanothread synthesis occurs when the starting material is compressed between the points of two diamonds. This diamond anvil cell is a frequently used tool for bringing matter to extreme pressures and Carnegie scientists have been pioneering leaders in deploying this research technique for decades. Credit: Samuel Dunning

As hard as diamond and as flexible as plastic, highly sought-after diamond nanothreads would be poised to revolutionize our world—if they weren’t so difficult to make.

Recently, a team of scientists led by Carnegie’s Samuel Dunning and Timothy Strobel developed an original technique that predicts and guides the ordered creation of strong, yet flexible, , surmounting several existing challenges. The innovation will make it easier for scientists to synthesize the nanothreads—an important step toward applying the material to practical problems in the future. The work was recently published in the Journal of the American Chemical Society.

Diamond nanothreads are ultra-thin, one-dimensional carbon chains, tens of thousands of times thinner than a human hair. They are often created by compressing smaller carbon-based rings together to form the same type of bond that makes the hardest mineral on our planet.

However, instead of the 3D-carbon lattice found in a normal diamond, the edges of these threads are “capped” with carbon-hydrogen bonds, which make the whole structure flexible.

Dunning explains, “Because the nanothreads only have these bonds in one direction, they can bend and flex in ways that normal diamonds can’t.”

Scientists predict that the unique properties of carbon nanothreads will have a range of useful applications from providing sci-fi-like scaffolding on space elevators to creating ultra-strong fabrics. However, scientists have had a hard time creating enough material to actually test their proposed superpowers.

“If we want to design materials for specific applications,” says Dunning, “it’s essential for us to precisely understand the structure and bonding of the nanothreads we’re making. This thread directing method really allows us to do that.”

One of the biggest challenges is getting the carbon atoms to react in a predictable way. In nanothreads made from benzene and other six-atom rings, each carbon atom can undergo with different neighbors. This leads to many possible reactions competing with one another and many different nanothread configurations. This uncertainty is one of the biggest hurdles scientists face to synthesize nanothreads where the precise chemical structure can be determined.

Dunning’s team determined that adding nitrogen to the ring in place of carbon might help guide the reaction down a predictable pathway. They chose to start their work with pyridazine—a six-atom ring made up of four carbons and two nitrogens—and began working on a computer model. Dunning worked with Bo Chen, Donostia International Physics Center, and Li Zhu, Assistant Professor at Rutgers and Carnegie Alum, to simulate how pyridazine molecules behave at .

“In our system, we use two nitrogen atoms to remove two possible reaction sites from the ring system. This dramatically reduces the number of possible reactions,” says Dunning.

The starting sample of pyridazine—a six atom ring made up of four carbons and two nitrogens—changes under pressure as diamond nanothread formation progresses. The first and last images show that there has been a permanent color change between the samples after thread formation. The images don’t show individual threads, but “bulk” samples of pyridazine during compression, each around 40 microns thick with 180-micron diameters. Credit: Samuel Dunning

After running several computer simulations showing successful nanothread formation at high pressure, they were ready to take the experiment to the lab.

The team took a drop of pyridazine and loaded it into a diamond anvil cell—a device that allows scientists to produce extreme pressures by compressing samples between the tiny tips of more traditional diamonds. Using infrared spectroscopy and X-ray diffraction, they monitored changes in the pyridazine’s chemical structure up to about 300,000 times normal atmospheric pressure looking for the creation of new bonds.

When they saw the bonds forming, they realized they had successfully predicted and created the first pyridazine diamond nanothread in the lab.

“Our reaction pathway produces an incredibly orderly nanothread,” said Dunning. “The ability to incorporate other atoms into the nanothread backbone, guide the reaction, and understand the nanothread’s chemical environment will save researchers invaluable time in developing nanothread technology.”

This process of using these non- to guide the formation of nanothreads, which Dunning calls “thread directing,” is a significant step towards a future where scientists can predictably create these materials and use them for advanced applications. Now that this synthetic strategy has been discovered, Dunning plans to identify and test the many possible nanothread precursors.

He also can’t wait to start putting the pyridazine nanothreads through their paces.

Dunning concluded, “Now that we know we can make this material, we need to start making enough to learn enough to determine mechanical, optical, and electronic properties.”

More information:
Samuel G. Dunning et al, Solid-State Pathway Control via Reaction-Directing Heteroatoms: Ordered Pyridazine Nanothreads through Selective Cycloaddition, Journal of the American Chemical Society (2022). DOI: 10.1021/jacs.1c12143

Discovered: An easier way to create ‘flexible diamonds’ (2022, March 2)
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Hexbyte Glen Cove Slave room discovered at Pompeii in ‘rare’ find

Hexbyte Glen Cove

The little slave room contains three beds, a ceramic pot and a wooden chest.

Pompeii archaeologists said Saturday they have unearthed the remains of a “slave room” in an exceptionally rare find at a Roman villa destroyed by Mount Vesuvius’ eruption nearly 2,000 years ago.

The little room with three beds, a ceramic pot and a wooden chest was discovered during a dig at the Villa of Civita Giuliana, a suburban villa just a few hundred metres from the rest of the ancient city.

An almost intact ornate Roman chariot was discovered here at the start of this year, and archaeologists said Saturday that the room likely housed slaves charged with maintaining and prepping the chariot.

“This is a window into the precarious reality of people who rarely appear in historical sources, written almost exclusively by men belonging to the elite,” said Pompeii’s director general Gabriel Zuchtriegel.

The “unique testimony” into how “the weakest in the ancient society lived… is certainly one of the most exciting discoveries in my life as an archaeologist,” he said in a press release.

Pompeii was buried in ash when Mount Vesuvius erupted in 79 AD, killing those who hadn’t managed to leave the city in time. They were either crushed by collapsing buildings or killed by thermal shock.

‘Rare insight’

The 16-square metre (170-square feet) room was a cross between a bedroom and a storeroom: as well as three beds—one of which was child sized—there were eight amphorae, stashed in a corner.

The 16-square metre (170-square feet) room was a cross between a bedroom and a storeroom.

The wooden chest held metal and fabric objects that seem to be part of the harnesses of the chariot horses, and a chariot shaft was found resting on one of the beds.

The remains of three horses were found in a stable in a dig earlier this year.

“The room grants us a rare insight into the daily reality of slaves, thanks to the exceptional state of preservation of the room,” the Pompeii archaeological park said.

Experts had been able to make plaster casts of the beds and other objects in perishable materials which left their imprint in the cinerite—the rock made of volcanic ash—that covered them, it said.

Slave ‘family’

The beds were made of several roughly worked wooden planks, which could be adjusted according to the height of the person who used them.

The webbed bases of the beds were made of ropes, covered by blankets.

Two of the beds were around 1.7 metres long, and one measured just 1.4 metres, and may therefore have belonged to a child.

While two were around 1.7 metres long, one measured just 1.4 metres, and may therefore have belonged to a child.

The archaeological park said the three slaves may have been a family.

Archaeologists found several personal objects under the beds, including amphorae for private things, ceramic jugs and what might be a chamber pot.

The room was lit by a small upper window, and there are no traces or wall decorations, just a mark believed to have been left by a lantern hung on a wall.

The excavation is part of a programme launched in 2017 aimed at fighting illegal activity in the area, including tunnel digging to reach artefacts that can be sold on illicit markets.

The Villa of Civita Giuliana had been the target of systematic looting for years. There was evidence some of the “archaeological heritage” in this so-called Slave Room had also been lost to looters, the park said.

Damage by grave robbers in the villa had been estimated so far at almost two million euros ($2.3 million), it added.

© 2021 AFP

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Hexbyte Glen Cove Discovered: How ladybugs stick to surfaces without losing legs at takeoff thumbnail

Hexbyte Glen Cove Discovered: How ladybugs stick to surfaces without losing legs at takeoff

Hexbyte Glen Cove

Figure 1. Ladybird beetle on a glass surface. Its white tarsal setae can be seen in contact with the surface. Credit: National Institute for Materials Science

NIMS, the University of Tokyo and the University of Kiel have jointly ascertained the tarsal adhesion mechanisms employed by ladybird beetles, which had been debated for decades.

Strong adhesives are commonly used to firmly bond materials together. Their use hinders recycling—one of our efforts to build a sustainable society—by making it more difficult to disassemble and sort waste products. Efforts are therefore underway to develop new, environmentally friendly adhesive technologies that have high bonding strength but are also easier to detach. Some scientists in biomimetics have been studying the ability of reptiles and insects to easily walk on ceilings and walls by quickly and repeatedly attaching and detaching their tarsi to and from these surfaces. This research team has been researching and developing new adhesive technologies using the efficient tarsal functions of ladybird beetles as a model. This beetle is capable of walking on glassy, smooth surfaces without slipping despite the fact that the portion of its tarsi which comes into contact with the surface is covered with rigid setae. This portion of the tarsi also secretes fluid. Based on these observations, two potential tarsal adhesion mechanisms had been proposed: a mechanism involving intermolecular forces of attraction between tarsal setae and the walking surface and another mechanism involving the of the secreted tarsal fluid. The debate over which was correct remained unresolved for 40 years.

This research team recently succeeded in measuring the thickness of the tarsal fluid layer formed between the setal tips of a ladybird beetle and the glass surface on which the beetle was placed, under the presumption that this thickness indicates the strength of the intermolecular of attraction between the tarsi and the surface. To make this measurement, the team first formed an AuPd particle layer 10 to 20 nm in thickness on the glass surface. The beetle was then placed on the coated surface and allowed to secrete tarsal fluid. The tarsal fluid was then instantaneously frozen while the beetle’s legs were still resting on the coated surface. The legs were then detached from the surface and the height of the AuPd particle layer filled with the frozen tarsal fluid was measured under a Cryo-SEM microscope. As a result, the thickness of the tarsal layer (i.e., the distance between the setal tips of the beetle and the glass ) was found to be sufficiently narrow for intermolecular forces of attraction to act effectively. The team then measured traction forces of ladybird beetles walking on the surfaces of various substrates using a combination of biomimetic and materials science techniques in order to determine the relative contributions of intermolecular forces and other adhesion forces. Intermolecular forces are known to be correlated with work of adhesion (WA), the amount of energy required to separate two connected surfaces of different materials. The correlation between WA and traction forces was therefore examined by fitting experimental data into a mathematical formula describing the relationship between these two parameters. As a result, the tarsal adhesion force of the beetle was found to be correlated with WA, indicating that intermolecular forces (i.e., van der Waals forces) are the primary force involved in the tarsal adhesion of ladybird beetles.

In future studies, the team plans to apply these results to the development of artificial structures capable of attaching and detaching themselves to and from various substrates. These structures may be used in the feet of disaster relief robots capable of traveling on various surfaces in a manner similar to ladybird beetles. They also may be integrated into devices designed to replace parts within high-precision equipment.

This research was published in the April 8, 2021 issue of Scientific Reports.

More information:
Naoe Hosoda et al, Evidence for intermolecular forces involved in ladybird beetle tarsal setae adhesion, Scientific Reports (2021). DOI: 10.1038/s41598-021-87383-9

Discovered: How ladybugs stick to surfaces without losing legs at takeoff (2021, June 23)
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Hexbyte Glen Cove Newly discovered Miocene biome sheds light on rainforest evolution thumbnail

Hexbyte Glen Cove Newly discovered Miocene biome sheds light on rainforest evolution

Hexbyte Glen Cove

Selected plant taxa from the Zhangpu biota. Credit: NIGPAS

An international research group led by Prof. Wang Bo and Prof. Shi Gongle from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) has collected approximately 25,000 fossil-containing amber samples and about 5,000 fossil plants in Zhangpu County, Fujian Province, southeast China from 2010 to 2019.

Their findings were published in Science Advances on April 30.

The Zhangpu biota, including amber biota and co-occurring megafossils, is the richest tropical seasonal biota discovered so far. It reveals that extraordinary species diversity existed within a 14.7 million-year-old tropical rainforest and sheds light on the evolution of the rainforest.

Diverse winged fruits of Dipterocarpaceae and legumes, as well as leaves of 78 different broadleaf trees show that tropical seasonal rainforests extended further north than today, offering an insight into what changes might take place in a future warmer world if ecosystems are able to adapt.

The Zhangpu amber biota contains a diverse, exquisitely preserved fossil arthropod fauna and abundant botanical and other inclusions such as fungi, snails, and even feathers. Botanical inclusions include bryophytes (liverworts and mosses) and flowering plants.

Arthropod inclusions cover an impressive array of more than 250 families including various spiders, mites, millipedes, and at least 200 families of insects in 20 orders. The extremely high variety of arthropods renders the Zhangpu amber biota one of the world’s four richest, along with the widely known Cretaceous Burmese amber biota (> 568 families), Eocene Baltic amber biota (> 550 families), and Miocene Dominican amber biota (205 families).

Representative inclusions in Zhangpu amber. Credit: NIGPAS

The insect fauna in Zhangpu amber include many ants, bees, lacewings, stick insects, termites, and grasshoppers that are today restricted to tropical Southeast Asia and/or New Guinea.

“The most unexpected finding is that the high diversity of ants and springtails all belong to living genera. In addition, the vast majority of previously identified insects in Zhangpu amber, such as bark lice, grasshoppers, beetles, and bees, also belong to living genera,” said Prof. Wang.

These results suggest that Asian rainforest insect communities have remained stable since the middle Miocene (at least 15 million years ago). It also highlights that tropical rainforests act as museums of biological diversity at the generic level. The relative ecological stability of such “megathermal” environments facilitates the continued accumulation of species diversity and makes them even more precious than previously realized.

The Zhangpu amber biota is unique because the samples are not commercially extracted and consequently the species census is minimally skewed by human selective bias. Moreover, its precise age is well-constrained by radioisotopic dating and the associated plant compression/impression fossils allow quantitative reconstruction of the ancient climate.

Ecological reconstruction of the Zhangpu biota. Credit: NIGPAS

Compared to the modern climate of Zhangpu, the most notable difference is that the middle Miocene climate had a warmer winter, leading to a relatively stable temperature throughout the year.

In scenarios of global warming, winter warming is commonly more pronounced than summer warming, and has larger and more widespread effects on terrestrial and marine ecosystems. It reduces “winterkills” and is beneficial for reproduction and growth of tropical animals and plants.

“Winter warming is likely to have been a major driver of the northern expansion of the megathermal biota in South China during the Mid-Miocene Climatic Optimum,” said Prof. Shi.

More information:
“The mid-Miocene Zhangpu biota reveals an outstandingly rich rainforest biome in East Asia” Science Advances (2021). DOI: 10.1126/sciadv.abg0625

Newly discovered Miocene biome sheds light on rainforest evolution (2021, April 30)
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Hexbyte Glen Cove Key steps discovered in production of critical immune cell thumbnail

Hexbyte Glen Cove Key steps discovered in production of critical immune cell

Hexbyte Glen Cove

dendritic cells stained by PS100 was found in corneal epithelium. Credit: Zhiguo.he

WEHI researchers have uncovered a process cells use to fight off infection and cancer that could pave the way for precision cancer immunotherapy treatment.

Through gaining a better understanding of how this process works, researchers hope to be able to determine a way of tailoring immunotherapy to better fight .

Led by Dr. Dawn Lin and Dr. Shalin Naik and published in Nature Cell Biology, the research provides new insight into the way cells adapt to fight .

This research lays the foundation for future studies into the body’s response to environmental stressors, such as injury, infection or cancer, at a single cell level.

Flt3L hormone plays vital role in fighting off infection

Dendritic cells are that activate ‘killer’ T cells, which are vital for clearing viral infections, such as COVID-19, but also for triggering a response to cancers such as melanoma and bowel cancer.

The Flt3L hormone can increase dendritic cell numbers, helping the immune system to fight off cancer and infection.

Dr. Naik and his team studied developing immune cells at a single cell level to gain a deeper understanding of how the body uses these cells to trigger immune responses.

“There is one type of dendritic cell that the body uses to fight some infections and cancer. The Flt3L hormone increases numbers of this particular dendritic cell. We know quite well how the dendritic cell fights the cancer, but we don’t know how the Flt3L hormone increases the numbers of those dendritic cells,” he said

Single-cell barcoding provides vital clues to how dendritic cells function

Researchers used a single-cell ‘barcoding’ technique to uncover what happened when dendritic cells multiplied.

“By using cellular barcoding—where we insert short synthetic DNA sequences, we call barcodes inside cells—we were able to determine which cells produced dendritic cells in pre-clinical models,” Dr. Naik said.

“As a result of this research, we now better understand the actions of the Flt3L hormone that is currently used in cancer immunotherapy trials, and how it naturally helps the body fight cancer and infection. This is a first step to design better precision immunotherapy treatments for cancer.”

Using single cell technology to improve immunotherapy treatment

This research answers a 50-year-long question as to what causes a stem cell to react in response to immense stress, such as infection or inflammation.

“We have known that the Flt3L hormone increases the number of for decades but now there is a focus on applying this knowledge to cancer immunotherapy and potentially to infection immunotherapy as well,” Dr. Naik said.

“The next stage in our research is to create ‘dendritic cell factories’ using our new knowledge, to produce millions to billions of these infection fighting and then use those in immunotherapy treatments.”

“These findings are a vital first step to improving treatments for patients, to help them better fight cancer and infection.”

More information:
Dawn S. Lin et al. Single-cell analyses reveal the clonal and molecular aetiology of Flt3L-induced emergency dendritic cell development, Nature Cell Biology (2021). DOI: 10.1038/s41556-021-00636-7

Key steps discovered in production of critical immune cell (2021, March 2)
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