Study sheds new light on materials assembly in confinement

Study sheds new light on materials assembly in confinement
Researchers from Cornell used computer simulations to show how the assembly of vertex-truncated tetrahedra is affected when confined inside a spherical container. The findings offer materials scientists a new method for controlling the assembly structure and characteristics of the resulting material. Credit: Rachael Skye

Cramming multiple pairs of shoes into a vacation suitcase, twisting and flipping them into different arrangements to fit every pair needed, is a familiar optimization problem faced by harried travelers. This same problem is well known to engineers—when given a number of objects with a particular shape, how can they be packed into a container? And which pattern will that packing form?

Unlike the contents of a suitcase, the way in which are packed together can be used to engineer the characteristics of the materials they form; for instance, how light or electricity travel through. Materials scientists have long studied how assembling particles in a confined space can be used as a tool to give materials new abilities, but how particles with unique shapes interact with a barrier remains poorly understood.

A new study by researchers in Cornell University’s Department of Materials Science and Engineering used to show how the assembly of vertex-truncated tetrahedra—a that has four hexagonal faces and four triangular faces—is affected when confined inside a spherical container. The findings, published in the journal Soft Matter, offer materials scientists a new method for controlling the assembly structure and characteristics of the resulting material.

Study sheds new light on materials assembly in confinement
Simulations of 10,000 particles in spherical containers, (a–c) viewed from the outside, and (d–f) as cross sections. Three different shapes are highlighted: Platonic tetrahedra (a and d), space-filling truncated tetrahedra (b and e), and Archimedean truncated tetrahedra (c and f). Coloration corresponds to the local particle environments: blues represent particles that are predominantly vertex-to-vertex, and oranges correspond to predominantly vertex-to-edge. White particles are uncategorized. The simulations show that a wall can change the behavior of particles near it, allowing researchers to selectively assemble different structures. Credit: Rachael Skye

“It used to be that theorists would primarily do simulations with spheres because most particles are roughly spherical, and computationally that was easiest,” said Rachael Skye, doctoral student and first author of the study, “but experimentalists keep coming up with exciting ways to control shape and now they can make like tetrahedra, octahedra, or cubes. With advanced computing power, we can simulate these shapes, but also go further and predict what new, not-yet-synthesized particles might do.”

To help fill the knowledge gap in how these particle shapes assemble in confinement, Skye and the study’s senior author, Julia Dshemuchadse, assistant professor of and engineering, simulated tetrahedral particle assemblies in spherical containers. Each held as few as four particles and as many as 10,000. In each simulation, the container would shrink as much as possible with the programmed number of particles inside it.

“This simulation is mimicking how some colloidal materials are produced, with particles placed inside a liquid droplet which contracts as it evaporates,” said Dshemuchadse.

These particles can fit together in a number of ways, but there are two distinct motifs: aligned, with hexagonal faces adjacent, or anti-aligned, with a hexagonal face adjacent to a triangular one. Each motif drives an overall structure that conforms to the containers’ borders differently.

Study sheds new light on materials assembly in confinement
An example of a colloidal cluster from confined self-assembly in a water-in-oil emulsion droplet, a project led by Friedrich-Alexander University Erlangen-Nürnberg. The Cornell simulations could help control the assembly of future colloidal materials. Credit: Wang, J., Mbah, C.F., Przybilla, T. et al. Magic number colloidal clusters as minimum free energy structures. Nat Commun

“If you have these anti-aligned particles, then you can form flat layers really well and stack infinitely wide, making a really good crystal,” said Dshemuchadse, who added that this motif is favored when simulating large numbers of particles because the larger container size has smaller curvature, “but if you have the particles aligned, the structure can form a curved motif that fits better into a spherical shell. At small numbers of particles, the aligned motif is favored because the smaller containers have large curvatures.”

The findings provide with a method to grow large crystals in systems of particles that do not typically assemble into ordered structures. Other methods of achieving a well-ordered crystal involve techniques such as “seeding” the material with particles constrained in specialized orientations that drive the corresponding structure, but such methods require fabricating new types of particles, which would be less straightforward in an experimental realization of these systems. In contrast, forming crystals on a flat substrate is often the norm, and this study points to how this technique may benefit the resulting structure.

“Colloidal crystals tend to be small and full of defects, but in order for them to be useful in most applications, they need to be fairly large and defect free” Skye said. “The idea is that by choosing your container or wall correctly, you can make a crystal that is much bigger and of better quality than you otherwise could.”

Skye added that in fields such as plasmonics and photonics, this assembly technique can be used to orient the same particle in two different ways, enabling engineers to create devices that have different responses based on the chosen assembly formation.


Bottom-up construction with a 2D twist could yield novel materials


More information:
Rachael S. Skye et al, Tuning assembly structures of hard shapes in confinement via interface curvature, Soft Matter (2022). DOI: 10.1039/D2SM00545J

Provided by
Cornell University


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Algeria fire crews rein in blazes that left 38 dead

An Algerian woman in front of the ruins of her home, destroyed in a wildfire in the city of El Kala, on August 18, 2022
An Algerian woman in front of the ruins of her home, destroyed in a wildfire in the city of El Kala, on August 18, 2022.

Algerian firefighters on Thursday brought under control a string of forest blazes that have killed at least 38 people including 12 who died in a bus trapped by the flames.

Deadly fires have become an annual scourge in Algeria, where climate change has turned large areas of forest into a tinderbox in the blistering summer months.

Authorities have been accused of being ill-prepared, with few firefighting aircraft available despite record casualties in last year’s blazes and a cash windfall from gas exports amid soaring global energy prices.

Fire service spokesman Farouk Achour told AFP late Thursday that 16 fires were still burning across seven districts but that those in the worst-hit eastern areas, El Tarf and Souk Ahras, were under control.

In Souk Ahras, a large crowd gathered to mourn five members of the same family who perished in the flames.

The justice ministry launched an inquiry after Interior Minister Kamel Beldjoud suggested some of the fires were deliberately started, and authorities on Thursday announced four arrests of suspected arsonists.

At least 38 people have been killed including more than 10 children and 10 firefighters, according to multiple sources, including local journalists and the .

Most were in the El Tarf region near Algeria’s eastern border with Tunisia, an area which has been sweltering in 48 degree Celsius (118 Fahrenheit) heat.

At least 200 more people have suffered burns or respiratory problems, according to various Algerian media.

Forest fires in northern Algeria
Map of Algeria showing burnt zones since August 1.

Algerian television showed people fleeing burning homes, women carrying children in their arms.

A journalist in El Tarf described “scenes of devastation” on the road to El Kala, a northeastern seaport.

“A tornado of fire swept everything away in seconds,” he told AFP by telephone.

An AFP team in El Kala saw burned-out cars, exhausted people and charred trees amid the strong smell of smoke.

A witness, who asked not to be named, said 12 people had burned to death in their bus as they tried to escape when the fire ripped through an animal park.

Takeddine, a worker at the park who declined to give his full name, said staff had helped families with young children to escape as fire surrounded the park.

“Nobody came to help us, neither the fire service nor anyone else,” he told AFP.

One of his colleagues died in the process, he added.

Strong winds accentuated the blazes
Strong winds accentuated the blazes.

Authorities criticised

A medic in El Kala said 72 people had been admitted to the city’s hospital, where nine had died and another nine remained in intensive care.

Associations across Algeria called for donations of money and medical supplies to help the victims.

The service said Thursday afternoon that 1,700 firefighters had been deployed to battle the fires, of which 24 were still raging.

A journalist in the mountainous area of Souk Ahras told AFP that a huge blaze in a forest nearby had sparked panic in the city of half a million people, where nearly 100 women and 17 newborn babies had to be evacuated from a hospital.

The scenes were reminiscent of fires last year which killed at least 90 people and seared 100,000 hectares (247,000 acres) of forest and farmland in the country’s north.

That disaster provoked criticism of authorities over the lack of firefighting aircraft.

Algeria had agreed to buy seven such aircraft from Spanish firm Plysa, but cancelled the contract following a diplomatic row over the Western Sahara in late June, according to specialist website Mena Defense.

Authorities have rented a Russian water bomber, but it broke down and is not expected to be operational again until Saturday, Interior Minister Kamel Beldjoud said.

The civil protection service and the army have access to several firefighting helicopters.

Experts have called for a major effort to bolster the firefighting capacity of Africa's biggest country
Experts have called for a major effort to bolster the firefighting capacity of Africa’s biggest country.

‘The forest is weakened’

Experts have called for a major effort to bolster the firefighting capacity of Africa’s biggest country, which has more than four million hectares of forest.

One specialist, who asked not to be named, told AFP that in the 1980s the country had 22 Grumman aircraft for battling forest fires but that they had been “sold on the cheap, without any alternative solution being proposed”.

Since early August, fires have destroyed more than 800 hectares of forest and 1,800 hectares of woodlands, according to Beldjoud.

On Thursday, Prime Minister Aimene Benabderrahmane defended the government’s response, saying that the country had ordered four new firefighting aircraft—but that they would not be available until December.

He added that had exacerbated the blazes and said authorities were “deploying all their means” to extinguish them.

Retired academic and forestry expert Rafik Baba-Ahmed said in a video published on social media that “winds of over 90 kilometres (55 miles) per hour make the work of water bombers difficult if not impossible”.

He said bad land management had added to the problem.

“Today, the is weakened. It has been chipped away at,” he said.


Portugal, Spain struggle to control forest fires


© 2022 AFP

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Newly discovered magnetic interactions could lead to novel ways to manipulate electron flow

A breakthrough in magnetic materials research could lead to novel ways to manipulate electron flow with much less energy loss
Graphical representation of the crystal structure of the TbMn6Sn6 material at the atomic level. Here the Mn and Tb atoms appear as blue and green balls, respectively. Lines connecting near neighbors reveal the Mn Kagome and Tb triangular lattices. The magnetism present on this element is represented by arrows located on each individual atom. The magnetic interactions acting within and in-between the different atomic planes are displayed by the square brackets and labeled by the letter “J” with the subscript M and T used to denote the Mn or Tb elements they link. Credit: U.S. Department of Energy Ames National Laboratory

Newly discovered magnetic interactions in the Kagome layered topological magnet TbMn6Sn6 could be the key to customizing how electrons flow through these materials. Scientists from the U.S. Department of Energy’s Ames National Laboratory and Oak Ridge National Laboratory conducted an in-depth investigation of TbMn6Sn6 to better understand the material and its magnetic characteristics. These results could impact future technology advancements in fields such as quantum computing, magnetic storage media, and high-precision sensors.

Kagomes are a type of material whose structure is named after a traditional Japanese basket weaving technique. The weave produces a pattern of hexagons surrounded by triangles and vice-versa. The arrangement of the atoms in Kagome metals reproduces the weaving pattern. This characteristic causes electrons within the material to behave in unique ways.

Solid materials have controlled by the characteristics of their electronic band structure. The band structure is strongly dependent on the geometry of the atomic lattice, and sometimes bands may display special shapes such as cones. These special shapes, called topological features, are responsible for the unique ways electrons behave in these materials. The Kagome structure in particular leads to complex and potentially tunable features in the electronic bands.

Using magnetic atoms to construct the lattice of these materials, such as Mn in TbMn6Sn6, can further help inducing topological features. Rob McQueeney, a scientist at Ames Lab and the project leader, explained that topological materials “have a special property where under the influence of magnetism, you can get currents which flow on the edge of the material, which are dissipationless, which means that the electrons don’t scatter, and they don’t dissipate energy.”

The team set out to better understand the magnetism in TbMn6Sn6 and used calculations and neutron scattering data collected from the Oak Ridge Spallation Neutron Source to conduct their analysis. Simon Riberolles, a postdoc research associate at Ames Lab and member of the project team, explained the experimental technique the team used. The technique involves a beam of neutron particles which is used to test how rigid the magnetic order is. “The nature and strength of the different present in the materials can all be mapped out using this technique,” he said.

They discovered that TbMn6Sn6 has competing interactions between the layers, or what is called frustrated magnetism. “So the system has to make a compromise,” McQueeney said, “Usually what that means is that if you poke at it, you can get it to do different things. But what we found out in this material is that even though those competing interactions are there, there are other interactions that are dominant.”

This is the first detailed investigation of the magnetic properties of TbMn6Sn6 to be published. “In research, it’s always exciting when you figure out you understand something new, or you measure something that has not been seen before, or was understood partially or in a different manner,” Riberolles said.

McQueeney and Riberolles explained that their findings suggest the material could potentially be adjusted for specific , for example by changing the Tb for a different rare earth element, which would change the magnetism of the compound. This fundamental research paves the way for continued advances in Kagome metals discovery.

This research is further discussed in the paper published in Physical Review X.


Magnetism generated in 2D organic material by star-like arrangement of molecules


More information:
S. X. M. Riberolles et al, Low-Temperature Competing Magnetic Energy Scales in the Topological Ferrimagnet TbMn6Sn6, Physical Review X (2022). DOI: 10.1103/PhysRevX.12.021043

Provided by
Ames Laboratory


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Compact QKD system paves the way to cost-effective satellite-based quantum networks

Compact QKD system paves the way to cost-effective satellite-based quantum networks
Researchers experimentally demonstrated a space-to-ground QKD network using a compact QKD terminal aboard the Chinese Space Lab Tiangong-2 and four ground stations. Credit: Cheng-Zhi Peng, University of Science and Technology of China

Researchers report an experimental demonstration of a space-to-ground quantum key distribution (QKD) network using a compact QKD terminal aboard the Chinese Space Lab Tiangong-2 and four ground stations. The new QKD system is less than half the weight of the system the researchers developed for the Micius satellite, which was used to perform the world’s first quantum-encrypted virtual teleconference.

The demonstration represents an important step toward practical QKD based on constellations of small satellites, a setup considered one of the most promising routes to creating a global quantum communication network.

“QKD offers unconditional security by using single photons to encode information between two distant terminals,” said research team member Cheng-Zhi Peng from the University of Science and Technology of China. “The compact system we developed can reduce the cost of implementing QKD by making it possible to use .”

Peng and researchers from other institutions in China describe their new system and experimental results in Optica. They also found that QKD performance can be boosted by building a network of satellites orbiting at different angles, or inclinations, in relation to the equator.

“Our new work demonstrates the feasibility of a space-ground QKD network based on a compact satellite payload combined with constellations of satellites with different orbit types,” said Peng. “In the near future, this type of QKD system could be used in applications that require high security such as government affairs, diplomacy and finance.”

Compact QKD system paves the way to cost-effective satellite-based quantum networks
The researchers created the compact payload—shown here in ground experiments— that allowed the Tiangong-2 Space Lab to act as a satellite QKD terminal. It included a tracking system, QKD transmitter and a laser communication transmitter. Credit: Cheng-Zhi Peng, University of Science and Technology of China

Shrinking the QKD system

QKD uses the quantum properties of light to generate secure random keys for encrypting and decrypting data. In previous work, the research group demonstrated satellite-to-ground QKD and satellite-relayed intercontinental quantum networks using the Micius satellite. However, the QKD system used aboard that satellite was bulky and expensive. About the size of a large refrigerator, the system weighed around 130 kg and required 130 W of power.

As part of China’s quantum constellation plan, the researchers sought to develop and demonstrate a more practical space-ground QKD network. To do this, they developed a compact payload that allowed the Tiangong-2 Space Lab to act as a satellite QKD terminal. The QKD payload—consisting of a tracking system, QKD transmitter and a laser communication transmitter—weighed around 60 kg, required 80 W of power and measured about the size of two microwave ovens.

“This payload was as integrated as possible to reduce volume, weight and cost while achieving the high performance necessary to support space-to-ground QKD experiments,” said Peng. “It also had to be very durable to withstand harsh conditions such as the severe vibration experienced during launch and the extreme thermal vacuum environment of space.”

The researchers performed a total of 19 QKD experiments during which secure keys were successfully distributed between the Space Lab terminal and four on 15 different days between October 2018 and February 2019. These experiments were conducted at night to avoid the influence of daylight background noise.

The researchers found that the medium (~42°) inclination orbit of the space lab allowed multiple passes over a single ground station in one night, which increased the number of keys that could be generated. They also built a model to compare the performance of satellite-based QKD networks with different orbit types. They found that combining satellites with a medium-inclination orbit like the space lab with a sun-synchronous orbit that travels over the polar regions achieved the best performance.

Compact QKD system paves the way to cost-effective satellite-based quantum networks
Satellite-based QKD transmission could be used to create a highly secure global quantum communication network. Credit: Cheng-Zhi Peng, University of Science and Technology of China

Next steps

The researchers are now working to improve their QKD system by increasing the speed and performance of the QKD system, reducing cost, and exploring the feasibility of daytime satellite-to-ground QKD transmission. “These improvements would allow a practical quantum constellation to be created by launching multiple low-orbit satellites,” said Peng. “The constellation could be combined with a medium-to-high-orbit quantum satellite and fiber-based QKD networks on the ground to create a space-ground-integrated quantum network.”

Although not part of this work, an even smaller quantum satellite developed by Hefei National Laboratory and University of Science and Technology of China and other research institutes in China was successfully launched into space on July 27. This satellite, known as a micro/nano satellite, weighs about a sixth the weight of the Micius satellite and contains a QKD system that is about a third of the size of that demonstrated in the Optica paper. That satellite is designed to carry out real-time satellite-to-ground QKD experiments, representing another important step toward low-cost and practical quantum constellations.


The world’s first integrated quantum communication network


More information:
Yang Li et al, Space–ground QKD network based on a compact payload and medium-inclination orbit, Optica (2022). DOI: 10.1364/OPTICA.458330

Citation:
Compact QKD system paves the way to cost-effective satellite-based quantum networks (2022, August 18)
retrieved 18 August 2022
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Hunting pythons in Florida, for profit and therapy

Enrique Galan is professional hunter helping control the Everglades' python population, estimated to be in the tens of thousands
Enrique Galan is professional hunter helping control the Everglades’ python population, estimated to be in the tens of thousands. .

Enrique Galan is seldom happier than when he disappears deep into the Everglades to hunt down Burmese pythons, an invasive species that has been damaging Florida’s wetland ecosystem for decades.

When not working at his job staging cultural events in Miami, the 34-year-old spends his time tracking down the nocturnal reptiles from Southeast Asia.

He does so as a professional hunter, hired by the Florida Fish and Wildlife Conservation Commission (FWC) to help control the python population, estimated to be in the tens of thousands.

At night, Galan drives slowly for miles on paved roads and gravel tracks, his flashlight playing on grassy verges and tree roots, and the banks of waterways where alligator eyes occasionally glint.

He charges $13 an hour and an additional fee per python found: $50 if it’s up to four feet (1.2 meters), and $25 more for each additional foot.

But on this August night, he has an extra motivation.

The FWC has been holding a 10-day python-hunting contest, with 800 people participating. The prize is $2,500 for whoever finds and kills the most pythons in each of the categories—professional and amateur hunter.

And Galan would love to win that money to celebrate the arrival of Jesus, his newborn baby.

Burmese pythons, originally brought to the United States as pets, have become a threat to the Everglades since humans released t
Burmese pythons, originally brought to the United States as pets, have become a threat to the Everglades since humans released them into the wild in the late 1970s.

Pets released into wild

Burmese pythons, originally brought to the United States as pets, have become a threat to the Everglades since humans released them into the wild in the late 1970s.

The snake has no , and feeds on other reptiles, birds, and mammals such as raccoons and white-tailed deer.

“They’re an amazing predator,” says Galan in admiration.

Specimens in the Everglades average between six and nine feet long, but finding them at night in the wetland of more than 1.5 million acres (607,000 hectares) takes skill and patience.

Galan has a trained eye, as well as the courage and determination needed for the job. After two unsuccessful nights, he spots a shadow on the shoulder of Highway 41: he jumps out of his truck and lunges at the animal, a baby Burmese python.

Grabbing it behind the head to avoid being bitten, he puts it in a cloth bag and ties it with a knot. He will kill it hours later with a BB gun.

A few miles further on, a huge python slithers across the tarmac. Galan again bolts from his truck but this time the snake escapes into the grass, leaving behind a strong musky scent, a defense mechanism.

  • Hired by the Florida Fish and Wildlife Conservation Commission (FWC), Enrique Galan searches for Burmese pythons, in Everglades
    Hired by the Florida Fish and Wildlife Conservation Commission (FWC), Enrique Galan searches for Burmese pythons, in Everglades National Park, Florida on August 8, 2022.
  • At night, hunters drive slowly for miles on paved roads and gravel tracks, his flashlight playing on grassy verges and tree root
    At night, hunters drive slowly for miles on paved roads and gravel tracks, his flashlight playing on grassy verges and tree roots, and the banks of waterways.
  • The Everglades National Park at dusk
    The Everglades National Park at dusk.

Therapy for some

Galan took an online training course before hunting pythons, but says he learned everything he knows from Tom Rahill, a 65-year-old who founded the Swamp Apes association 15 years ago to help war veterans deal with traumatic memories through hunting.

For a few hours, Rahm Levinson, an Iraq war veteran suffering from post-traumatic stress disorder, hunts with Rahill and Galan.

“It really helped me through a lot of stuff struggling at home,” he said.

“I can’t sleep at night and having someone to go out at 12 o’clock, two o’clock in the morning, and catch pythons is something productive and good.”

Galan is proud to participate in a project that has eliminated more than 17,000 pythons since 2000.

“One of the best things that I get out of it is the amount of beauty that I’m just surrounded by. If you just look closely, open your eyes and observe, you’ll see a lot of magic here.”


Calling all snake hunters—Florida opens registration for this year’s Python Challenge


© 2022 AFP

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Snow research fills gap in understanding Arctic climate

Dogs lying in the middle of the road after sunrise at Kewa Pueblo, in no hurry to start the day
Statistical models based on several seasons of field research on the distribution of snow in Alaska are leading to a deeper understanding of changing hydrology, topography and vegetation dynamics in the Arctic and sub-Arctic. Credit: Los Alamos National Laboratory

Comprehensive data from several seasons of field research in the Alaskan Arctic will address uncertainties in Earth-system and climate-change models about snow cover across the region and its impacts on water and the environment.

“Snow cover and its distribution affects not only the Arctic but global energy balances, and thus how it is changing is critically important for understanding how future global climate will shift,” said Katrina Bennett, lead author of the paper in The Cryosphere. Bennett is principal investigator at Los Alamos National Laboratory for the Department of Energy’s Next Generation Ecosystem Experiment Arctic project. “Our statistical model fills in the gap in understanding the of snow.”

The research found that spatial distribution depends most heavily on vegetation, elevation and , such as stream banks and benches—areas of topographic variability where shrubs grow and snow accumulates.

Based on random-forest machine learning, the characterizes the spatial pattern of the end-of-winter snow distribution and identifies the key factors controlling the spatial distribution. The model also predicts the snow distribution for the local study sites and can be generalized across the region.

Bennett said the analysis will be useful in validating physically based permafrost hydrology models, such as the Advanced Terrestrial Simulator developed at Los Alamos. The work will also help validate and provide improved snow redistribution representation in the land surface model within the Department of Energy’s Energy Exascale Earth System Model.

“Ultimately, it will increase our understanding of changing hydrology, topography and vegetation dynamics in the Arctic and sub-Arctic,” Bennett said.

Seasons in the snow

The multi-institutional research team, which included members from Los Alamos, University of Alaska Fairbanks, Lawrence Berkeley National Laboratory, Oak Ridge National Laboratory and University of Wisconsin–Madison, conducted snow surveys in the spring months of 2017–2019 at two small sites on the Seward Peninsula.

“We want to gratefully acknowledge Mary’s Igloo, Sitnasuak and Council Native Corporation for their guidance and for allowing us to conduct our research on their traditional lands,” Bennett said.

The focused on collecting end-of-winter snow-depth and snow-density measurements to calculate the amount of water contained within the snowpack. Those measurements characterize the impacts of on water and temperature better than snow-depth measurements do.

To create a model of snow distribution, the team estimated landscape factors for topography, vegetation and wind, and then quantified their impacts on snow distribution using three statistical models.


Investigating the dynamics that reshape permafrost environments


More information:
Katrina E. Bennett et al, Spatial patterns of snow distribution in the sub-Arctic, The Cryosphere (2022). DOI: 10.5194/tc-16-3269-2022

Citation:
Snow research fills gap in understanding Arctic climate (2022, August 17)
retrieved 17 August 2022
from https://phys.org/news/2022-08-gap-arctic-climate.html

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Technique for ready-to-use cells in research demonstrated

Technique for ready-to-use cells in research demonstrated by University of Warwick and Cryologyx
Credit: University of Warwick

A new technique for freezing cells for use in biomedical research, based on polymer technology developed at the University of Warwick, has been validated in study, paving the way for faster results for scientists in their research.

Cells attached as monolayers (grown on plastic) are used in , toxicology, biomaterials and in all . However, they cannot be cryopreserved whilst attached to this plastic, creating a major bottleneck.

University of Warwick technology now allows cells to be stored frozen attached to the plastic, and are “ready to use” direct from the freezer removing a significant bottleneck in the drug discovery process.

The ability to freeze and bank cells as monolayers has taken a major step forward, solving a long-term problem in the paper “Assay-Ready Cryopreserved Cell Monolayers Enabled by Macromolecular Cryoprotectants” published by the University of Warwick’s Department of Chemistry and Warwick Medical School, working with the biotech Cryologyx Ltd. Crucial to this is polymer technology developed over the last decade at the University of Warwick.

When discovering new drugs, or understanding fundamental cell biology, most cells are studied whilst attached to tissue culture plastic (adherent cells). Ideally, researchers would just take cells out of the freezer, thaw them, and then use them. However, current cryopreservation technologies only allow cells to be stored in suspension—researchers must thaw, and then grow, the cells for 7–14 days before use. This is inefficient and means researchers and industry spend more time growing the cells, than studying them.

The GibsonGroup, working with Cryologyx, have solved this long-standing problem using their macromolecular cryoprotectant technology—CryoShield. The cryoprotectants protects the cells against cold stress, meaning the cells can be taken from the freezer, thawed and in less than 24 hours rather than the two weeks currently required, then are ready to use.

This impressive data represents a step-change in cryopreservation and will facilitate the discovery of new drugs, identify toxic compounds, screen for viruses and much more. This work has been supported by a European Research Council Proof of Concept grant awarded to Professor Matthew Gibson, to translate their team’s research from the lab to industry, as well as by InnovateUK, the Biotechnology and Biological Sciences Research Council and Cryologyx Ltd.

Professor Matthew Gibson who holds a joint appointment between the Department of Chemistry and Warwick Medical School at the University of Warwick and is a co-founder of Cryologyx comments that “cryopreservation is fundamental to so much modern bioscience and medicine but using current technologies, once you thaw the cells you can spend two weeks working before you actually get your data. We have a mission to make the process easier—so you can decide to do an experiment on Monday, and have the data by the end of Tuesday. This would save costs and time in drug discovery.

“Our core technology are macromolecular cryoprotectants—polymers which protect the cells from cold stress. We are really excited to be able to do the science, but also translate this into our spin-out company who are developing the assay-ready .”

Dr. Thomas Congdon who is CEO and co-founder of Cryologyx says that “CryoLogyx works directly with cell biologists, in university research groups, and SMEs, to large biotech and pharma companies. Across the board they are excited at the potential that cryopreserved cell monolayers have for accelerating research and revolutionizing how they work and what they can achieve in the lab.”

“We are incredibly proud to collaborate on the research being carried out at University of Warwick. This work shows that three of the most used cell lines in the world can be made truly assay-ready. It is a great achievement with the potential to save researchers incalculable hours in lab and reduces the cost of drug discovery programs by tens, if not hundreds, of millions of pounds.”

The research was published in Biomacromolecules.


Freezing cells made safer thanks to new polymer


More information:
Ruben M. F. Tomás et al, Assay-ready Cryopreserved Cell Monolayers Enabled by Macromolecular Cryoprotectants, Biomacromolecules (2022). DOI: 10.1021/acs.biomac.2c00791

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Technique for ready-to-use cells in research demonstrated (2022, August 17)
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US cuts water supply for some states, Mexico as drought bites

The huge Lake Mead, which was formed by the damming of the Colorado River, is at historically low levels
The huge Lake Mead, which was formed by the damming of the Colorado River, is at historically low levels.

Water supplies to some US states and Mexico will be cut to avoid “catastrophic collapse” of the Colorado River, Washington officials said Tuesday, as a historic drought bites.

More than two decades of well below have left the river—the lifeblood of the western United States—at critical levels, as human-caused climate change worsens the natural drought cycle.

Despite years of warnings and a deadline imposed by Washington, states that depend on the river have not managed to agree on a plan to cut their usage, and on Tuesday, the federal government said it was stepping in.

“In order to avoid a catastrophic collapse of the Colorado River System and a future of uncertainty and conflict, in the Basin must be reduced,” said Tanya Trujillo, assistant secretary for and science at the US Interior Department.

Arizona’s allocation from the river will fall by 21 percent in 2023, while Nevada will get eight percent less. Mexico’s allotment will drop by seven percent.

California, the biggest user of the river’s water and the most populous of the western states, will not be affected next year.

The Colorado River rises in the Rocky Mountains and snakes its way through Colorado, Utah, Arizona, Nevada, California and northern Mexico, where it empties into the Gulf of California.

It is fed chiefly by snowpack at high altitudes, which melts slowly throughout the warmer months.

But reduced precipitation and the higher temperatures caused by humanity’s unchecked burning of fossil fuels means less snow is falling, and what snow exists, is melting faster.

As a consequence, there is not as much water in the river that supplies tens of millions of people and countless acres of farmland.

Plants grow from an exposed lakebed drying out during low water levels due to the western drought on June 28, 2022, on Lake Mead
Plants grow from an exposed lakebed drying out during low water levels due to the western drought on June 28, 2022, on Lake Mead along the Colorado River in Boulder City, Nevada.

The states that use the water have been locked in negotiations over how to slash usage, but missed a Monday deadline to cut a deal, so Washington stepped in.

Officials in upstream states hit out Tuesday at what they saw as an unfair settlement, with California exempted from any cuts.

“It is unacceptable for Arizona to continue to carry a disproportionate burden of reductions for the benefit of others who have not contributed,” said a statement by Tom Buschatzke, director of the state’s Department of Water Resources and Ted Cooke, general manager of the Central Arizona Project.

Climate change

Deputy Interior Secretary Tommy Beaudreau said his department—which oversees US —was “using every resource available to conserve water and ensure that irrigators, Tribes and adjoining communities receive adequate assistance.”

“The worsening drought crisis impacting the Colorado River Basin is driven by the effects of climate change, including and low precipitation,” he said.

“In turn, severe drought conditions exacerbate wildfire risk and ecosystems disruption, increasing the stress on communities and our landscapes.”

The western United States is suffering under a drought that is now in its 23rd year, the worst episode in more than 1,000 years.

That has left swathes of the country dry and vulnerable to hotter, faster and more destructive wildfires.

Communities served by the Colorado River, including Los Angeles, have been ordered to save water, with unpopular restrictions in place on outdoor watering.

Those restrictions are unevenly adhered to, with some lawns—especially in the plushest parts of Los Angeles and its surroundings—still remarkably green.


Deadline looms for western states to cut Colorado River use


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US cuts water supply for some states, Mexico as drought bites (2022, August 17)
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Chicken bones and snail shells help archaeologists to date ancient town’s destruction

Chicken bones and snail shells help archaeologists to date ancient town’s destruction
Spring 107 BC destruction layer of the Seleucid settlement of Tell Izṭ abba. Credit: German-Israeli Tell Izṭabba ̣Excavation Project

According to new research, the combined analysis of animal and plant remains, as well as written evidence, is leading to more precise dating of archaeological finds. “We can now often determine not only the year, but also the season. This allows us to reconstruct the events that produced the finds much more precisely,” say archaeologists Prof. Dr. Achim Lichtenberger from the Cluster of Excellence “Religion and Politics” at the University of Münster and his Tel Aviv University colleague Prof. Oren Tal.

“The destruction of the Greek town Tell Iẓṭabba in present-day Israel by a military campaign waged by the Hasmoneans, a Judean ruling dynasty in the 2nd and 1st centuries BC, has so far been dated to between 111 and 107 BC,” say Lichtenberger and Tal. “More recent research dates it to 108/107 BC, based on coin finds and the siege of the city of Samaria at the same time. Now, using our multi-proxy approach that makes use of several , we can for the first time date the events with certainty to the of 107 BC.”

“We came across chicken leg bones in the dwellings destroyed by the Hasmoneans. Analyzing them revealed residues containing medullary bone deposits in the marrow that served to produce eggshells during the laying season in spring. This indicates that the chickens were slaughtered in spring,” explain Achim Lichtenberger and Oren Tal. “We also discovered the shells of field snails, which were often eaten at this time of year.” Botanical examinations of the remnants of flowers on the floors of the dwellings reveal that these plants flowered in spring.

Analysis of the objects is always accompanied by analysis of written evidence: “The contemporary Hebrew scroll of Megillat Ta’anit about the Hasmonean conquest, also known as the Scroll of Fasting, reports the expulsion of the inhabitants in the Hebrew month of Sivan, which corresponds to our May/June.”

‘Only the multiplicity of analytical methods makes precise statements possible’

“From an archaeological point of view, this makes spring the season of destruction,” says Lichtenberger and Tal, which underlines previous findings on Hellenistic warfare, as military offensives usually took place in spring and early summer.

“The individual data taken on their own would not justify determining such a clear ,” emphasizes Lichtenberger, who, together with his colleague Oren Tal and an interdisciplinary team comprising natural scientists, is leading a research project on the archaeology of the Hellenistic settlement Tell Iẓṭabba, in ancient Nysa-Scythopolis, a Greek city in the ancient Near East. “Only by taking an overall view of the results from all analytical methods can we provide more precise information about the time of the destruction of Tell Iẓṭabba, and thus about the course of the Hasmonean campaign.” The finds must therefore be interpreted in the light of the seasons.

The research was published in Antiquity.


Easternmost Roman aqueduct discovered in Armenia


More information:
Oz Rittner et al, For everything there is a season: more than a year of destruction at Seleucid Tell Izṭ abba (Israel), Antiquity (2022). doi.org/10.15184/aqy.2022.92

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Antiquity

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Chicken bones and snail shells help archaeologists to date ancient town’s destruction (2022, August 16)
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Understanding a new college student’s experience

college
Credit: CC0 Public Domain

The W-Curve Model was first proposed in 1963 to explain adjustment to culture shock. Starting college is a culture shock for many young people. It is often the first time students are away from home for an extended period.

Freshman year is known for , but it also presents various challenges. Each new college student’s experience is unique. Parents should be aware of the predictable adjustment pattern to help students navigate difficult times.

The five stages of the W-Curve Model explain students’ level of comfort, satisfaction and effectiveness during each stage:

1. Honeymoon: The excitement stage

Often starting before students arrive at college, the honeymoon stage is full of excitement, stimulation and curiosity. There’s increased enthusiasm to meet new people, and many are intriguing.

Students desire independence and tend to lack homesickness during the first few days or weeks of college. New students are bombarded with events and activities, keeping the excitement level high.

2. Culture shock: Reality sets in

At this stage, students may start to compare their expectations of college with reality. The differences that felt new and exciting start to feel isolating and overwhelming.

Students may feel lost and confused, noticing that the excitement of living on their own has worn off. Often, students will compare their experiences to others, finding that academic demands are more complex than anticipated.

Feeling homesick may lead students to wish to return home more often.

3. Initial adjustment: Settling into the demands of college life

College gets better as students begin to manage experiences from shock. This can include making friends outside of their initial connections, developing a routine, gaining confidence in academic and social abilities, and finding one’s roommate less bothersome.

This is when students start to reconnect to what they like about themselves and the new culture of college.

4. Mental isolation: Comparing home and college

After students go home during an academic break, they may not feel as comfortable at home as they used to. Students may feel distressed at changes or events at home during their absence. This leads them to feel unsure about where they belong and miss the comfort that home used to provide. Beliefs and values are challenged as students attempt to find their place in the world.

At this time, peer conflicts may increase, and students may have a more tough time with roommates. Students in dating relationships that started in may have an increasingly hard time after seeing their partner during a break.

5. Acceptance and integration: Finally, balance emerges

Students develop stronger ties to fellow and faculty, get more involved in campus life, and understand how to succeed academically. Students often start referring to campus as their home and feel like a part of the culture. Roommate issues are addressed, and dependence on hometown connections begins to lessen. Students start to feel like an old hand at living the college life.

Making the first year of college a success

The first year at college is not always easy. Being aware of the predictable adjustment pattern can make the transition less intimidating. If college is too overwhelming, help is always available, whether it’s talking to a friend, family member, resident adviser, professor or a mental health professional. Understanding the W-Curve Model can help support their student’s success in .


Time off after high school makes college less likely


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The W-Curve Model: Understanding a new college student’s experience (2022, August 16)
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