Diminishing Arctic sea ice has lasting impacts on global climate

Credit: CC0 Public Domain

As the impacts of climate change are felt around the world, no area is experiencing more drastic changes than the northern polar region. Studies have shown the Arctic is warming at two to three times as fast as the rest of the planet, resulting in a rapid loss of its sea ice volume.

That , declining at an average rate of about 13 percent per decade, is having a long-lasting climatic impact in the Arctic and beyond, according to a new study published this month in Nature Communications.

The research team, led by University at Albany atmospheric scientist Aiguo Dai, analyzed observational data and climate model simulations to show how fluctuations in Arctic sea ice cover are able to amplify multi-decadal variations in not only in the Arctic, but also in the North Atlantic Ocean.

Their results indicate that recent—and future—decreases in sea ice cover have a significant influence on global climate.

“Through our study, we demonstrated for the first time that fluctuations in sea ice-air interactions can greatly enlarge or amplify multi-decadal not only in the Arctic, but also the North Atlantic,” said Dai, a distinguished professor at UAlbany’s Department of Atmospheric and Environmental Sciences.

“As the melting of Arctic sea ice continues, its impacts are likely to be felt even more in coming decades, not only in the Arctic but over the North Atlantic and other regions across the globe,” said Dai. “This is because sea surface temperature anomalies in the North Atlantic can affect atmospheric circulation patterns over Europe, North America, West Africa and South America, leading to temperature and precipitation changes in these regions.”

Sea ice-air interactions

The researchers used publicly available observational data, coupled with two novel climate model simulations carried out through a computer hosted at the UAlbany Data Center. In one simulation, Arctic sea ice cover was allowed to fluctuate freely based on changing climatic conditions, while the other parallel simulation was run without year-to-year sea-ice fluctuations.

When sea ice cover was fixed, multidecadal climate variations were reduced, both in the Arctic and North Atlantic, by 20 to 50 percent. This suggests that sea ice-air interactions play a crucial role in regulating climate variations.

The researchers ran additional simulations using rising carbon dioxide levels by 1 percent per year to further confirm their results. They are currently examining other possible influences of Arctic sea ice, such as on El Nino-Southern Oscillation in the tropical Pacific.

Jiechun Deng, an atmospheric scientist at Nanjing University of Information Science and Technology, worked as a research fellow with Dai at UAlbany from 2018 to 2020. He is the lead author of the study.

“Working with Prof. Dai at UAlbany was a truly inspiring experience,” Deng said. “Our research highlights the crucial role of sea ice-air coupling in amplifying multidecadal variability. In doing so, it contributes to the ongoing debate on the role of sea ice in the recent decadal temperature trend in both Arctic and midlatitudes.”

Arctic amplification

This study is the latest in a series of Nature Communications articles published by Dai and his team over the last several years that focus on changes in the Arctic climate.

In 2019, Dai led a study examining the causes of Arctic Amplification (AA), the term used to describe the Arctic’s warming rates at two to three times the rest of the planet. The climate simulations used for that study showed that additional AA will not diminish until nearly all the Arctic’s sea ice has melted away in the 23rd century.

Further, that study concluded that AA would not exist if surface fluxes were calculated with a fixed sea ice cover, again suggesting that Arctic sea ice loss has profound climatic impacts.

“The take-home message here is that the Arctic region is very important for Earth’s climate and the rapid melting of its sea ice has and will continue to have significant climatic impacts worldwide,” Dai said.



More information:
Jiechun Deng et al, Sea ice–air interactions amplify multidecadal variability in the North Atlantic and Arctic region, Nature Communications (2022). DOI: 10.1038/s41467-022-29810-7

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Hexbyte Glen Cove Researchers design a flexible system that sidesteps copper-protein binding

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The structure of the designed metalloprotein with selective metal binding sites. Credit: Chung-Jui Yu

It may seem counterintuitive to many, but metal ions play a critical role in life, carrying out some of the most important biological processes. Think of hemoglobin—a metalloprotein responsible for carrying oxygen to the body’s organs via red blood cells. Metalloproteins are proteins bound by at least one metal ion. In the case of hemoglobin, that metal is iron.

For metalloproteins to work properly, they must be paired with the correct —hemoglobin can only function with iron Yet, protein-metal binding is normally governed by a strict order, called the Irving-Williams Series, which dictates that should bind to proteins over other metals.

In other words, if a cell contained equal amounts of different metal ions, most cellular proteins and other components would bind to , clogging up cellular machinery in the process. This is why organisms spend considerable energy keeping very strict controls over how much free copper is present in cells.

Now researchers in the University of California San Diego’s Division of Physical Sciences have reported a new protein-design strategy to sidestep the Irving-Williams Series. The findings were published earlier this week in the journal Nature.

Professor of Chemistry and Biochemistry Akif Tezcan and postdoctoral scholar Tae Su Choi designed a flexible protein that selectively binds other metal ions over copper, paving the way for the design of novel functional proteins and metal sequestration agents. Choi and Tezcan discovered that selective binding to non-copper metals required the artificial protein to present a very specific combination of amino acids and geometries to discriminate against copper. This discovery required an uncommon design approach.

“Protein design typically involves trying to craft a discrete protein structure that can perform a certain function, such as catalysis. This approach is inherently deterministic and follows the sequence of one design-one structure-one function,” stated Tezcan. “Best case scenario, you obtain the structure and function that is designed. However, this approach doesn’t leave much room for the discovery of new design principles or unexpected outcomes, which are potentially more significant than what was originally planned.”

Tezcan and Choi took a probabilistic approach instead. At the outset, their designed protein wasn’t engineered to possess a singular structure that selectively binds to a certain type of metal. They created a flexible system that could arrange itself in multiple ways to bind different metal ions in different geometries. It was this flexibility that led them to an outcome they did not originally plan for.

“In analyzing these systems, we saw that proteins were binding to cobalt and nickel ions ahead of copper, which is not the natural order of things,” stated Choi. “We created an hypothesis and tested new variants. After extensive analysis, we realized we could construct a protein environment where copper was disfavored.”

“This is an example of designing a pathway rather that a target,” explained Tezcan. “I personally think that this is a more exciting way to go about the protein design problem. By incorporating an element of flexibility into the design, we leave open the possibility of different outcomes and new design principles we couldn’t have known beforehand.”

Research on selective binding and design has importance beyond a better understanding of the fundamentals of life. It can also lay the foundation for more efficient processes during environmental remediation, such as when certain metals need to be sequestered in contaminated water. Protein design is also a critical part of pharmaceutical research and development.

“We were intrigued by the question ‘Can we proteins that can selectively bind to metals or have catalytic reactions in ways that evolution has not yet invented?'” said Choi. “Just because biology doesn’t do it, it doesn’t mean it’s not possible.”



More information:
Tae Su Choi et al, Overcoming universal restrictions on metal selectivity by protein design, Nature (2022). DOI: 10.1038/s41586-022-04469-8

Citation:
Researchers design a flexible system that sidesteps copper-protein binding (2022, March 4)
retrieved 5 March 2022
from https://phys.org/news/20

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Hexbyte Glen Cove Nature-inspired coatings could power tiny chemistry labs for medical testing and more

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A newly developed coating that allows for certain liquids to move across surfaces without fluid loss could usher in new advances in a range of fields, including medical testing.

This new coating—created in the DREAM (Durable Repellent Engineered Advanced Materials) Laboratory, led by University of Toronto Engineering Professor Kevin Golovin—was inspired by the natural world.

“Nature has already developed strategies to transport liquids across surfaces in order to survive,” says Mohammad Soltani, researcher in the DREAM Laboratory and lead author of a new paper recently published in Advanced Functional Materials.

“We were inspired by the structural model of natural materials such as cactus leaves or spider silk. Our can directionally transport not only , but also low tension liquids that easily spread on most surfaces.”

The innovation has important implications for microfluidics, a field where small quantities of liquids are transported within tiny channels, often less than a millimetre wide. This technique has many applications, one of them being to miniaturize the standard analytical tests that are currently preformed in chemical laboratories.







New polymer coatings, developed by Professor Kevin Golovin and his team at the University of Toronto, show the precision with which liquids can move across surfaces. Credit: Mohammad Soltani / University of Toronto Engineering

By reducing the quantity of sample and reagents required, and automating protocols for working with them, microfluidics can power lab-on-a-chip devices that offer fast, inexpensive medical tests. Proponents hope this could lead to diagnosing multiple conditions in minutes using only a drop or two of blood.

But current microfluidic devices have a key limitation: they can only effectively handle liquids with high surface tension, such as water. This property, also known as cohesion, means that the has a greater tendency to stick to itself than to the sides of the channel it is being transported through.

High surface tension liquids form discrete droplets that can be moved around independently, like raindrops on window glass. Cohesion can even be exploited to pull the liquid droplets along the channel through a process known as .

By contrast, low surface tension liquids, such as alcohols and other solvents, tend to stick to the sides of the channels, and can currently be transported for only about 10 millimetres before the droplet disintegrates. Capillary action no longer applies, so this transport requires an external force, such as magnetism or heat, to move the droplets.

The new coating enables low surface tension liquids to be transported over distances of over 150 millimetres without losing any of the liquid, about 15 times longer than currently possible.







Credit: University of Toronto

The technology uses two newly developed polymer coatings, one of which is more liquid-repellent than the other. Both are composed of liquid-like polymer brushes. The more repellent coating acts as a background, surrounding the less repellent and creating tiny channels along the surface. The channels allow for the liquids to move in a desired pattern or direction without losing any of the liquid during transport or requiring additional energy input.

“Polymer brush coatings reduce the fluid friction and allow the droplets to be transported passively,” says Soltani, “Less friction means more energy is available to transport the liquid. We then create a driving force by designing the channels with specific patterns.”

The ability to transport low surface tension liquids without loss will allow for advancements in lab-on-a-chip devices. Using these unique coatings, researchers have the ability to transport liquids over a longer range, move multiple liquids at the same time along a precise pathway and even merge and split droplets—all without losing any volume or experiencing cross-contamination.

This technology will also help limit waste in research labs. With no residue left behind on the surface of the device and therefore no risk of cross-contamination, researchers can use the same devices over and over again.

“We’re looking at using this technology for microfluidics bioassays, as this is an area where every drop of liquid is precious,” says Golovin. “Our findings also have great potential to advance point-of-care diagnostics, such as liver or kidney disease, where biological marker screening is often performed in non-aqueous media.”



More information:
Mohammad Soltani et al, Lossless, Passive Transportation of Low Surface Tension Liquids Induced by Patterned Omniphobic Liquidlike Polymer Brushes, Advanced Functional Materials (2021). DOI: 10.1002/adfm.202107465

Citation:
Nature-inspired coatings could power tiny chemistry labs for medical testing and more (2021, October 22)
retrieved 24 October 2021
from https://phys.org/news/2021-10-nature-inspired-coatings-power-tiny-chemistry.html

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Hexbyte Glen Cove Black Americans are most likely to experience fatal police violence thumbnail

Hexbyte Glen Cove Black Americans are most likely to experience fatal police violence

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Credit: Pixabay/CC0 Public Domain

More than 55% of deaths from police violence in the USA from 1980-2018 were misclassified or unreported in official vital statistics reports according to a new study in The Lancet. The highest rate of deaths from police violence occurred for Black Americans, who were estimated to be 3.5 times more likely to experience fatal police violence than white Americans.

Researchers estimate that the US National Vital Statistics System (NVSS), the government system that collates all in the USA, failed to accurately classify and report more than 17,000 deaths as being caused by during the 40-year study period.

“Recent high-profile police killings of Black people have drawn worldwide attention to this urgent public health crisis, but the magnitude of this problem can’t be fully understood without . Inaccurately reporting or misclassifying these deaths further obscures the larger issue of systemic racism that is embedded in many US institutions, including law enforcement. Currently, the same government responsible for this violence is also responsible for reporting on it. Open-sourced data is a more reliable and comprehensive resource to help inform policies that can prevent police violence and save lives,” says co-lead author Fablina Sharara of the Institute for Health Metrics and Evaluation (IHME), University of Washington School of Medicine, USA.

To examine the extent of under-reporting, researchers compared NVSS data to three non-governmental, open-source databases on police violence: Fatal Encounters, Mapping Police Violence, and The Counted. These databases collate information from news reports and public record requests. When compared, the researchers’ new estimates highlight the extent to which deaths from police violence are under-reported in the NVSS and the disproportionate effect of police violence on Black, Hispanic, and Indigenous people in the USA.

Across all races and states in the USA, researchers estimate that NVSS data failed to report 17,100 deaths from police violence out of 30,800 total deaths from 1980-2018 (the most recent years of available NVSS data), accounting for 55.5% of all deaths from police violence during this period. Using a predictive model, researchers also estimated the total number of deaths from police violence in the USA, for all races/ethnicities and all states for 2019, estimating an additional 1,190 deaths, bringing the total number of deaths from police violence from 1980-2019 to 32,000.  

Black Americans experienced fatal police violence at a rate 3.5 times higher than white Americans, according to this analysis, with nearly 60% of these deaths misclassified in the NVSS (5,670 unreported deaths from police violence out of 9,540 estimated deaths). From the 1980s to the 2010s, rates of police violence increased by 38% for all races (with 0.25 deaths from police violence per 100,000 person-years in the 1980s as compared to 0.34 deaths from police violence per 100,000 person-years in the 2010s).

Compared to the deaths recorded in the new analysis, NVSS also missed 56% (8,540 deaths out of 15,200) of deaths of non-Hispanic white people, 33% (281 deaths out of 861) of non-Hispanic people of other races, and 50% (2,580 deaths out of 5,170) of Hispanic people of any race.

Deaths due to police violence were significantly higher for men of any race or ethnicity than women, with 30,600 deaths in men and 1,420 deaths in women from 1980 to 2019.

Previous studies covering shorter time periods have found similar rates of racial disparities, as well as significant under-reporting of police killings in official statistics. This new study is one of the longest study periods to date to address this topic.

The authors call for increased use of open-source data-collection initiatives to allow researchers and policymakers to document and highlight disparities in police violence by race, ethnicity, and gender, allowing for targeted, meaningful changes to policing and public safety that will prevent loss of life.

Additionally, the researchers point out that because many medical examiners or coroners are embedded within police departments, there can be substantial conflicts of interest that could disincentivize certifiers from indicating police violence as a cause of . Managing these conflicts of interest in addition to improved training and clearer instructions for physicians and medical examiners on how to document police violence in text fields on death certificates could improve reporting and reduce omissions and implicit biases that cause misclassifications.

“Our recommendation to utilize open-source data collection is only a first step. As a community we need to do more. Efforts to prevent police violence and address systemic racism in the USA, including body cameras that record interactions of police with civilians along with de-escalation training and implicit bias training for police officers, for example, have largely been ineffective. As our data show, fatal police violence rates and the large racial disparities in police killings have either remained the same or increased over the years. Policymakers should look to other countries, such Norway and the UK, where police forces have been de-militarized and use evidence-based strategies to find effective solutions that prioritize public safety and community-based interventions to reduce fatal police violence,” says co-lead author Eve Wool of the Institute for Health Metrics and Evaluation (IHME), University of Washington School of Medicine, USA.

The authors acknowledge some limitations in the study. This paper does not calculate or address non-fatal injuries attributed to police violence, which is critical to understanding the full burden of police violence in the USA and should be examined in future studies. The data also do not include police officers killed by civilians, police violence in USA territories, or residents who may have been harmed by military police in the USA or abroad. Because the researchers relied on death certificates, which only allow for a binary designation of sex, they were unable to identify non-cisgender people, potentially masking the disproportionately high rates of violence against trans people, particularly Black trans people.  The authors note that the intersectionality of gender, race/ethnicity, sexual orientation, and other identities and the relationship to fatal police violence should be studied in the future.

A Lancet Editorial adds, “The study is a potential turning point for improving national estimates of fatalities from police violence by incorporating non-governmental open-source data to correct NVSS data…Better data is one aspect of a public health approach; introducing harm-reduction policies is another. Policing in the USA follows models of hostile, racialised interactions between civilians and armed agents of the state. Marginalised groups are more likely to be criminalized through the war on drugs or homelessness. Reducing hostile or violent interactions between police and civilians, particularly those who are most vulnerable overall, is a forceful case for investment in other areas of community-based health and support systems, including housing, food access, substance use treatment, and emergency medical services. Strategies to lower fatalities from must include demilitarisation of , but with the broader call to demilitarize society by, for example, restricting access to firearms…Police forces too must take greater responsibility for police-involved injuries and deaths. Such changes are long overdue.”


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