Tech

In a recent study published in Marine Ecology Progress Series, researchers at California Polytechnic State University revealed that in addition to seasonal changes in winds and ocean temperatures, natural climate cycles greatly influenced the base of the food web at the Cal Poly Pier in San Luis Obispo Bay, an embayment located in Central California in the California Current Large Marine Ecosystem. Like seasons that drive recurring changes in ocean and atmospheric patterns every year, natural climate cycles drive rhythmic changes in these patterns over longer cycles.

The most commonly known natural climate cycle is the El Niño-Southern Oscillation (ENSO), which alters ocean and atmospheric weather patterns over the equatorial Pacific every three to eight years, with cascading effects on global weather patterns. However, along the California coast, other climate cycles such as the Pacific Decadal Oscillation (PDO) and North Pacific Gyre Oscillation (NPGO) can influence local ecosystems on cycles of a few years to a few decades. The study found that while local changes in temperature and nutrients influenced the overall community of phytoplankton that was present in San Luis Obispo Bay throughout the year, the state of these long-term climate cycles, i.e., the up or down points in these oscillating climate patterns, influenced the timing of when different phytoplankton groups appeared or if they appeared at all.

Primary producers such as phytoplankton form the base of the marine food web. These phytoplankton are eaten by small consumers like zooplankton and larval fish. As a result, changes at the base of the food web can affect organisms across multiple trophic levels in marine ecosystems. Researchers at Cal Poly have been collecting seawater samples over the last decade to gain insight into short term (seasonal) and long-term (interannual) changes in the base of the food web

"We care about the different types of phytoplankton because they have different impacts on the ecosystem," said Cal Poly biology professor Alexis Pasulka. "Some types provide better quality food for organisms like larval fish, whereas some types can produce toxins and have negative effects on local ecosystems."

Harmful algal blooms (HABs) are proliferations of aquatic algae that disrupt ecosystems and impair water quality. The environmental impacts of HABs can be sudden, severe and lethal across all levels of aquatic and terrestrial food webs. The types of phytoplankton that more commonly form HABs, dinoflagellates, are often associated with warmer waters that are less mixed by local winds.

"The phytoplankton are responding to changes in environmental conditions driven by the physics and motions of the ocean," said Cal Poly physics professor Ryan Walter. "These changes are not only happening seasonally but also over much longer time scales due to natural climate cycles like ENSO and PDO, as well as climate change due to human activity."

This study highlights that during the warm state of the PDO, i.e., the up in the PDO climate cycle, dinoflagellate blooms appeared more consistently in the fall and sometimes earlier in the seasonal cycle than during the cold state. This warm state of the PDO was characterized by increased surface temperatures and increased stratification (temperature changes with depth), both of which are expected to increase in the future due to global warming. This study may provide a glimpse into the future and a clue as to how the base of the food web and the prevalence of harmful algal blooms might respond to climate change-driven ocean warming.

Plastics are a victim of their own success, so inexpensive, easy to use and versatile that the world is awash in plastic waste. Now researchers from the University of Houston have reported a new method of producing polyolefins - made from hydrocarbons and the most common building block of plastics - structured to address one of the biggest stumbling blocks to plastics recycling.

The process also would allow plastics to be produced from food oils and other natural substances.

Eva Harth, director of the Welch-UH Center for Excellence in Polymer Chemistry, said the process addresses a long-standing need for industrial plastics producers, without requiring a new catalyst or expensive additives. "It's a very simple process," she said.

Harth is a corresponding author for a paper describing the discovery, published in the German journal Angewandte Chemie. Co-authors include co-corresponding author Glen R. Jones, a post-doctoral researcher with the Welch-UH Center, and first author Hatice E. Basburg Alhan, a graduate student at UH.

Polyolefins, and derivative products such as polyethylene and polypropylene, are used for everything from grocery bags to industrial pipes. The qualities of the plastics - rigidity vs. flexibility, for example - are determined in part by a chemical process known as branching: Jones said highly branched polyolefins are used in products that require softness or flexibility, such as grocery bags, while low branching is used to produce rigid plastics.

Traditionally, different catalysts have been required to spark differing levels of branching, Harth said, meaning that only one type of plastic could be produced at a time. "You have to be specific about what material you are after, what type of branching you need," she said.

The new method allows branching to be modulated using a palladium catalyst with varying amounts of added aluminum chloride, which functioned as a Lewis acid; the aluminum chloride - an abundant and inexpensive substance - can be added at different points in the process, allowing the resulting polyolefin to contain differing branching properties.

The new process could address two growing issues faced by plastics producers - how to dispose of plastic waste in an environmentally friendly way, and how to reduce the use of oil and natural gas by instead using food oils and other natural substances.

Current polymers used in everyday materials - grocery bags, milk jugs, toys and medical equipment, for example - won't readily mix when they are melted down for chemical recycling. "These new polymers could sit at the boundary," Jones said, allowing plastics with disparate properties to be more easily recycled.

The process will work with a variety of molecules to produce a polymer, Harth said, suggesting that the concept provides a new platform to produce plastics.

And that platform, she said, could lend itself to producing a variety of functional plastics from natural oils and other molecular sources. "This has exciting sustainability possibilities for the industry."

Turtle ant soldiers look like real-life creatures straight out of a Japanese anime film. These tree-dwelling insects scuttle to and fro sporting shiny, adorably oversized heads, which they use to block the entrances of their nests--essentially acting as living doors.

Not all heads are shaped alike: some soldiers have ones that resemble manhole covers and perfectly seal tunnel entrances. Others have square heads, which they assemble into multi-member blockades reminiscent of a Spartan army's overlapping shields. This variety in head shapes reveals more than just another of nature's quirky oddities: it can also shine a light on how species evolve to fill ecological niches. And that evolution, new research published in the Proceedings of the National Academy of Sciences shows, is not always a one-way street toward increasing specialization. Occasionally, it can take a species back to a more-generalist stage.

"Usually, you would think that once a species is specialized, it's stuck in that very narrow niche," says Daniel Kronauer, head of Rockefeller's Laboratory of Social Evolution and Behavior. "But turtle ants are an interesting case of a very dynamic evolutionary trajectory, with a lot of back and forth."

A match made in evolution

Like many other social insects living in colonies, turtle ants specialize for different functions, often evolving exaggerated features suited to their job. For the soldiers, this process has resulted in large heads that come in a variety of shapes.

"There's a whopping four-fold difference between the smallest and largest turtle ant soldier heads," says Scott Powell, a biologist at George Washington University and lead author of the new study. "To help people picture this, I often say that the smallest species is able to sit comfortably on the head of the largest species."

The shape and size of a turtle-ant soldier's head is dictated by the type of tunnel the species in question occupies. The ants don't dig the tunnels themselves, but move into those excavated by wood-boring beetles. And since a hand-me-down tunnel might be too big or too small, Kronauer says, the ants diversify rapidly to be able to occupy it.

The relationship between turtle-ant heads and tunnels can hence offer a uniquely clear insight into natural selection. Researchers can easily compare a trait--head circumference--with the ecological feature it's evolved to adapt to: the nest-entrance size. As Kronauer says, "It's a 1:1 match on the exact same scale."

A dynamic process

To examine the evolutionary journey of various head shapes, the researchers grouped 89 species of turtle ants based on whether soldiers sported a square, dome, disc, or dish-shaped head. They also included a group of turtle-ant species that don't have soldiers. They then examined the evolutionary relationships among these groups using the species' genetic information, which they had previously gathered.

If evolution was a one-way path, the first turtle ants that appeared some 45 million years ago should have lacked soldiers altogether, then gradually evolved toward specialization--starting with the generalist, square-headed soldiers, all the way to those with highly-tailored dish heads.

But the new analysis suggests that this was not the case. Instead, the oldest common ancestor the researchers could trace likely had a square head. That ancestor went on to form a range of species, from ones with no soldiers at all to others with different levels of specialization. In some cases, more specialist species reversed direction over time, evolving back into more generalist head shapes.

The finding nicely shows just how surprisingly flexible nature can be in fitting the shape of an organism to the context of the environment they occupy, Powell says.

"The space that evolution has to play with is actually quite a bit larger than previously thought," Kronauer adds.

GAINESVILLE, Fla. --- Botanist Cody Coyotee Howard compares bulbs to living bunkers. With an underground stockpile of resources, bulbs can hunker down during disasters and spring up faster than other plants when conditions turn balmy.

The bigger the bulb, the more nutrients a plant has in times of need. But bulb size varies widely, even among related species, from the chive's barely-there below-ground organ to softball-sized yellow onions. Howard wondered why.

His curiosity led to one of the first studies of the evolution and ecology of bulb size. In an analysis of more than 2,500 herbarium specimens, representing 115 species, he found two ranges of "optimum" bulb diameter that seem to be driven by natural selection. He also observed that larger bulbs tend to grow in warmer, more stable climates - perhaps because filling a bigger bunker requires favorable conditions over a longer time.

Why does bulb size matter? Besides contributing to a plant's ability to survive, it's a key trait in the garden business and agriculture. Horticulturists know that a plant will reliably flower when its bulb reaches a certain size. Bulb size is also a vital characteristic in crops such as garlic and onions.

"If we understand the evolution behind variation in bulb size, maybe we could manipulate settings to make it work more in our favor," said Howard, a recent University of Florida doctoral graduate in biology. "We do eat these structures, so understanding their evolution is important for horticulture and agriculture. They clearly have a role in how these plants respond to their environment."

Despite living underground, bulbs are not roots, but a reduced stem surrounded by swollen leaf bases.

Howard became interested in bulbs while working at the Huntington Botanical Gardens in Southern California, where he admired the beauty of exotic bulbs from around the world. As a graduate student, he focused on Ledebouria, an African group of bulbs, and began studying bulb evolution more broadly.

He recalled digging up two Ledebouria species growing side by side in Namibia. To his surprise, the smaller plant with thin leaves had the bigger bulb.

"It's not possible to predict bulb size by looking at the above-ground portion of a plant," he said. "And here you had two members of the same genus with different bulb sizes. I was curious about why that might be and wondered how I could look at that on a big scale. Then it was like, 'Ah, collections!'"

Howard relied on plant specimens collected by scientists around the world to carry out his investigation of bulb size. But although he analyzed thousands of plants, he didn't touch a single specimen. Thanks to the ongoing digitization of museum specimens, he could access all the plants he needed from his personal computer.

After drawing up a list of target species, he downloaded digitized specimens from the Global Biodiversity Information Facility, an open-access biological database. He searched specimens for ones that included bulbs and randomly selected a set from each species to measure virtually with ImageJ, an image processing program. Howard generated models of optimum bulb size using a free analytical software called R, and examined how climate data correlated with bulb size.

Instead of a single bell curve for bulb size, as he expected, the model showed two, suggesting that natural selection may favor two ranges of bulb diameter: peaking at about 2 and 4.5 centimeters.

Plants that grow leaves and flowers at separate times also tended to have bigger bulbs, possibly because they depend on their underground resources, rather than growing conditions, to fuel flower production, Howard said.

What began as a side project shined new light on the evolution and ecology of an important but often overlooked plant trait.

Plus, Howard said, "this project didn't cost me anything. People have developed free, user-friendly platforms that make it easy to start answering broadscale questions."

Howard's adviser and study co-author Nico Cellinese, Florida Museum of Natural History associate curator of the UF Herbarium and informatics, said the study "epitomizes the importance of herbarium specimens in general, but also demonstrates how digitized, freely available material can inspire and spearhead studies that lead to interesting results and new perspectives in science."

One plea Howard issued to fellow researchers was to include bulbs when collecting and curating plant specimens. In his search for eligible specimens, he turned up many herbarium sheets with leaves and flowers - but no bulb.

"It's understandable. With trees and shrubs, you can just take a few clippings. Getting a bulb is a much more involved process," he said. "But I wouldn't have been able to do a study like this if someone hadn't collected the entire specimen. We need these structures to be able to fully understand not only bulbous plants, but others with fascinating below-ground structures."

Billions of lightyears away, gigantic clouds of hydrogen gas produce a special kind of radiation, a type of ultraviolet light known as Lyman-alpha emissions. The enormous clouds emitting the light are Lyman-alpha blobs (LABs). LABs are several times larger than our Milky Way galaxy, yet were only discovered 20 years ago. An extremely powerful energy source is necessary to produce this radiation--think the energy output equivalent of billions of our sun--but scientists debate what that energy source could be.

A new study that published on March 9 in Nature Astronomy provides evidence that the energy source is at the center of star-forming galaxies, around which the LABs exist.

The study focuses on Lyman-alpha blob 6 (LAB-6), whose light was emitted 10.7 billion years ago. The collaborative team discovered a unique feature of LAB-6--its hydrogen gas appeared to fall inwards on itself. LAB-6 is the first LAB with strong evidence of this so-called infalling gas signature. The infalling gas was low in abundance of metallic elements, suggesting that the LAB's infalling hydrogen gas originated in the intergalactic medium, rather than from the star-forming galaxy itself.

The amount of infalling gas is too low to power the observed Lyman-alpha emission. The findings provide evidence that the central star-forming galaxy is the primary energy source responsible for Lyman-alpha emission. They also pose new questions about the structure of the LABs.

"This gives us a mystery. We expect there should be infalling gas around star-forming galaxies--they need gas for materials," said Zheng Zheng, associate professor of physics and astronomy at the University of Utah and co-author of the study. Zheng joined the effort of analyzing the data and led the theoretical interpretation with U graduate student Shiyu Nie. "But this seems to be the only Lyman-alpha blob with gas infalling. Why is this so rare?"

The authors used the Very Large Telescope (VLT) at the European Southern Observatory (ESO) and the Atacama Large Millimeter/Submillimeter Array (ALMA) to obtain the data. Lead author Yiping Ao of Purple Mountain Observatory, Chinese Academy of Sciences first observed the LAB-6 system over a decade ago. He knew there was something special about the system even then, based on the extreme size of its hydrogen gas blob. He jumped at the chance to look more closely.

"Luckily, we were able to obtain the data necessary to capture the molecular makeup from ALMA, pinning down the velocity of the galaxy," he said. "The optical telescope VLT from ESO gave us the important spectral light profile of Lyman-alpha emission."

Hydrogen's light reveals its secret

The universe is filled with hydrogen. The hydrogen electron orbits the atom's nucleus on different energy levels. When a neutral hydrogen atom gets blasted with energy, the electron can be boosted to a larger orbit with a higher energy level. Then the electron can jump from one orbit level to another, which produces a photon. When the electron moves to the inner-most orbit from the orbit directly adjacent, it emits a photon with a particular wavelength in the ultraviolet spectrum, called a Lyman-alpha emission. A powerful energy source is required to energize hydrogen enough to produce the Lyman-alpha emission.

The authors discovered the infalling gas feature by analyzing the kinematics of the Lyman-alpha emissions. After the Lyman-alpha photon is emitted, it encounters an environment filled with hydrogen atoms. It crashes into these atoms many times, like a ball moving in a pinball machine, before escaping the environment. This exit makes the emission extend outward over great distances.

All of this bouncing around not only changes the light wave's direction, but also its frequency, as the motion of gas causes a Doppler effect. When gas is outflowing, the Lyman-alpha emission shifts into the longer, redder wavelength. The opposite occurs when gas is inflowing--the Lyman-alpha emission's wavelength appears to get shorter, shifting it into a bluer spectrum.

The authors of this paper used the ALMA observation to locate the expected wavelength of the Lyman-alpha emission from the Earth's prospective, if there were no bouncing effect for the Lyman-alpha photons. With the VLT observation, they found that Lyman-alpha emission from this blob shifts into shorter wavelength, implying gas inflow. They used models to analyze the spectrum data and study the kinematics of hydrogen gas.

The infalling gas narrows down Lyman-alpha radiation's origin

LABs are associated with gigantic galaxies that are forming stars at a rate of hundreds to thousands of solar mass per year. Giant halos of Lyman-alpha emissions surround these galaxies, forming the Lyman-alpha gas blobs hundreds of thousands of light years across with power equivalent of about 10 billion suns. The movement within the gas blobs can tell you something about the state of the galaxy.

Infalling gas can originate several different ways. It could be the second stage of a galactic fountain--if massive stars die, they explode and push gas outward, which later falls inwards. Another option is a cold stream--there are filaments of hydrogen floating between celestial objects that can be pulled into the center of potential well, creating the infalling gas feature.

The authors' model suggests that the infalling gas in this LAB comes from the latter scenario. They analyzed the shape of the Lyman-alpha light profile, which indicates very little metallic dust. In astronomy, metals are anything heavier than helium. Stars produce the majority of the heavy elements in the universe—when they pulsate or explode, they spread metallic elements across interstellar space.

"If the gas had come from this galaxy, you should see more metals. But this one, there weren't a lot of metals," said Zheng. "The indication is that the gas isn't contaminated with elements from this star formation."

Additionally, their model indicates that the surrounding gas only produces the energy power equivalent of two solar masses per year, much too low for the amount for the observed Lyman-alpha emission.

The findings provide strong evidence that the star-forming galaxy is the major contributor of the Lyman-alpha emission, while the infalling gas acts to shape its spectral profile. However, it doesn't completely answer the question.

"There may still be other possibilities," said Ao. "If the galaxy has a super massive black hole in the center, it can emit energetic photons that could travel far enough to produce the emission."

In future studies, the authors want to tease apart the complicated gas dynamics to figure out why infalling gas is rare for LABs. The inflowing gas could depend on the orientation of the system, for example. They also want to build more realistic models to understand the movements of the Lyman-alpha emission photons as they crash into atoms.

What we learn through our senses drives how knowledge is sorted in our brains, according to research recently published in JNeurosci.

When we take a bite of an apple, we learn that "apples taste sweet" the same way we learn much of the information we know -- through a sensory experience. The brain stores such information in groups of neurons according to broad categories, like food and places. But, how does the brain store abstract knowledge that spans multiple categories, like "Granny Smith apples come from Australia"?

Scott Fairhall employed functional magnetic resonance imaging to monitor the brain activity of healthy adults while they answered questions about words from one of three categories - food, famous people, and cities. When participants thought about the tastiness of food, a part of the brain called the insula became active. When they thought about the region the food came from, the insula plus areas involved in spatial perception activated.

The brain relies on regions involved in taste whenever we think about food, even when taste is irrelevant information. Supplementing this knowledge with information from a group of neurons storing a different category of information allows complex knowledge that spans categories -- such as the origin of Granny Smith apples.

Below please find a summary of new article that will be published in the next issue of Annals of Internal Medicine. The summary is not intended to substitute for the full article as a source of information. This information is under strict embargo and by taking it into possession, media representatives are committing to the terms of the embargo not only on their own behalf, but also on behalf of the organization they represent.

1. New branded PrEP not worth the high cost compared with generic formulation

Abstract: http://annals.org/aim/article/doi/10.7326/M19-3478
Editorial: http://annals.org/aim/article/doi/10.7326/M20-0799
URL goes live when the embargo lifts

A newly approved drug for HIV pre-exposure prophylaxis (or PrEP) may undermine efforts to expand access to HIV prevention for the nation's most vulnerable populations, experts say. Findings from a cost-effectiveness study are published in Annals of Internal Medicine and will be presented at the Conference on Retroviruses and Opportunistic Infections (CROI) meeting in Boston.

PrEP, a pill taken once a day, reduces the risk of HIV infection via sex or injection drug use by up to 99 percent. Since 2012, there has been one FDA-approved PrEP formulation, the combination of tenofovir/emtricitabine (F/TDF). The availability of a less expensive generic formulation later this year is highly anticipated, as it may help to expand access to PrEP to some of the most difficult-to-reach segments of the at-risk population. Enthusiasm is tempered, however, by the introduction of a pricey new branded formulation, emtricitabine/tenofovir alafenamide (F/TAF), which was recently approved for PrEP in MSM. Determining the cost-effectiveness of F/TAF versus generic F/TDF is important for clinical decision-making and policymakers.

Researchers from Massachusetts General Hospital and Yale School of Public Health reviewed published research and data obtained from recently completed clinical trials to evaluate the cost-effectiveness of F/TAF for PrEP and to identify the highest possible price premium that branded F/TAF could command, even under the very best of circumstances, over generic F/TDF. The authors intentionally overstated the adverse clinical and economic consequences of generic F/TDF, inflating rates of bone and kidney disease incidence, assuming that all fractures would require surgical repair and that all cases of kidney disease would require dialysis and be irreversible. They found that even when they positioned branded F/TAF in the most favorable light possible, there was no plausible scenario under which F/TAF for PrEP would be a cost-effective alternative to generic F/TDF. According to the researchers, these findings suggest that branded F/TAF is not worth the high cost. They warn that if branded F/TAF drives out generic F/TDF and inhibits acceptability, access, and uptake, of the scale-up of PrEP in vulnerable populations, could stall, and F/TAF could end up causing more avoidable HIV transmissions than it prevents.

PHOENIX -- A study by researchers at Mayo Clinic in Arizona published in the the Journal of Clinical Investigation has found that obesity is not only implicated in chronic diseases such as diabetes, but also in sudden-onset diseases such as pancreatitis.

"In our study, we were able to demonstrate that fat within the belly is rapidly degraded during acute pancreatitis, but not during diverticulitis, despite inflammation," says Vijay Singh, M.B.B.S., a Mayo Clinic gastroenterologist.
Dr. Singh says while both diseases present with sudden belly pain and account for about 300,000 cases annually in the U.S., the rapid fat degradation that occurs in pancreatitis is triggered by a

pancreatic enzyme called PNLIP. This enzyme can form fatty acids that cause vital body systems like circulation, kidney and lung functions to fail. Dr. Singh says this multisystem failure is much more common in acute pancreatitis than in diverticulitis.

Dr. Singh says obesity, which increases belly fat, also can worsen acute pancreatitis. He says this highlights the role of obesity not just in the development chronic diseases such as diabetes, but also in the development of sudden-onset diseases such as pancreatitis.

Dr. Singh says the study also found that unsaturated fats, such as oleic acid contained in olive oil and recommended by the Food and Drug Administration as being safer for human consumption, actually increase the risk of organ failure. At the same time, PNLIP, the enzyme in the pancreas that breaks down stored fat in fat cells was not abundant in cells specialized for fat storage.

"Our findings open the door to new therapeutic targets to treat pancreatitis and thereby prevent organ failure," says Dr. Singh. "By inhibiting PNLIP, we may be able to prevent severe pancreatitis, avoid prolonged hospitalizations and save lives."

Mayo Clinic researchers involved in this study include:

Dr. Singh

Douglas Faigel, M.D.

Norio Fukami, M.D.

Rahul Pannala, M.D.

Doral Lam-Himlin, M.D.

Ann McCullough, M.D.

Dr. Singh reports no conflicts of interest.

Sea turtles around the world are threatened by marine plastic debris, mostly through ingestion and entanglement. Now, researchers reporting in the journal Current Biology on March 9 have new evidence to explain why all that plastic is so dangerous for the turtles: they mistake the scent of stinky plastic for food.

"We found that loggerhead sea turtles respond to odors from biofouled plastics in the same way they respond to food odorants, suggesting that turtles may be attracted to plastic debris not only by the way it looks, but by the way it smells," says Joseph Pfaller of the University of Florida, Gainesville. "This 'olfactory trap' might help explain why sea turtles ingest and become entangled in plastic so frequently."

Biofouling refers to the accumulation of microbes, algae, plants, and small animals on wet surfaces, which occurs to plastics in the ocean.

It has long been thought that sea turtles see plastics and visually mistake them for prey, such as jellyfish. But Pfaller and colleagues realized that little was known about the sensory mechanisms that might attract sea turtles to plastic.

In addition, study co-author Matt Savoca (@DJShearwater) of Stanford University's Hopkins Marine Station had shown that airborne odorants used by marine predators to locate good places to find food also emanate from marine-conditioned or biofouled plastic debris. So, they asked, what could that mean for sea turtles?

To find out, the researchers enlisted 15 young, captive-reared loggerhead turtles. They delivered a series of airborne odorants through a pipe in an experimental arena and recorded their reactions on video. The odors they tested included deionized water and clean plastic as controls along with the turtle's food, which contains fish and shrimp meal and biofouled plastic.

The behavioral studies found that sea turtles responded to biofouled plastic in the same way they responded to their food. Compared to control odors, the turtles kept their nares out of the water more than three times longer to get a good whiff.

"We were surprised that turtles responded to odors from biofouled plastic with the same intensity as their food," Pfaller said. "We expected them to respond to both to a greater extent than the control treatments, but the turtles know the smell of their food since they've been smelling and eating it in captivity for 5 months. I expected their responses to food to be stronger."

He says future studies are needed to better understand what chemicals were emitted from the plastics to pique the turtles' interest and how waterborne odorants might come into play. But the new findings show that plastics of all kinds will present problems for sea turtles and other marine animals.

"The plastic problem in the ocean is more complex than plastic bags that look like jellyfish or the errant straw stuck in a turtle's nose," Pfaller said. "These are important and troubling pieces to the puzzle, and all plastics pose dangers to turtles."

The ocean is getting too loud even for crabs. Normally, shore crabs (Carcinus maenas) can slowly change their shell color to blend in with the rocky shores in which they live, but recent findings show that prolonged exposure to the sounds of ships weakens their camouflaging powers and leaves them more open to attack. The work, appearing March 9 in the journal Current Biology, illustrates how man-made undersea noise can turn common shore crabs into sitting ducks for potential predators.

"Prior work had shown that ship noise can be stressful for shore crabs, so in this study, we wanted to address how that stress might affect behaviors they rely on for survival," says first author Emily Carter, a graduate from the University of Exeter. Unlike frogs or bats, who use sound to communicate or hunt, crabs don't primarily use sound to interact with each other. However, this study demonstrates that noise pollution can still affect important shore crab survival behaviors like the ability to camouflage and quickly respond to danger.

Carter placed dark-shelled juvenile shore crabs into white tanks. Within the tanks, crabs were exposed to the underwater sounds of a cruise ship, container ship, and oil tanker. As a control, other crabs listened to natural water sounds--played either quietly, or loud at a similar amplitude to the ship noise. Over 8 weeks, the crabs exposed to ship noise lightened their color to match their tanks only half as much as those which heard ambient water alone (both quiet and loud). Carter believes this reduced change in color demonstrates the unique effect of ship noise pollution on crab camouflage.

"Color change in shore crabs is a slow, energetically costly process that's controlled by hormones that activate specialized pigment cells across their shell," says Carter. "Stress consumes energy and disrupts hormone balance, so we believe that the stress caused by ship noise either drains the crabs of the energy required to change color properly or disrupts the balance of hormones necessary to make that change." The crabs also grew and molted much more slowly, showing that ship noise impacts multiple aspects of shore crab physiology.

What's more is that when crabs were subjected to a simulated shore bird attack, those that heard ship noise didn't run and hide as they would normally. "About half of the crabs exposed to ship noise did not respond to the attack at all, and the ones that did were slow to hide themselves," says Carter. "Similar to how people have trouble concentrating when stressed, the nature of their response indicates that they couldn't process what was happening, as if that awareness and decision-making ability just wasn't there."

In noise pollution research, the sounds of ships and other forms of man-made noise are typically studied for their effects on animals who directly use sound. Here, Carter, co-author Tom Tregenza, professor of evolutionary ecology at the University of Exeter, and senior author Martin Stevens, professor of sensory and evolutionary ecology at the University of Exeter, show that the noise pollution field should also consider behaviors based on their importance to survival rather than whether they have a direct link with noise.

"This work shows how processes like color change, which are not directly linked to acoustics, can still be affected by noise and how even animals like crabs are impacted by noise pollution--not just species that actively use sound, such as many fish or mammals," says Stevens.

To expand upon this research, Stevens' lab is investigating how multiple stressors, including that of noise pollution and warming oceans, could work synergistically to disrupt the coloration and behavior of marine organisms.

Colour-changing crabs struggle to camouflage themselves when exposed to noise from ships, new research shows.

Shore crabs - the most common on UK shores - can change colour to match their surroundings.

But University of Exeter scientists have discovered that crabs exposed hourly to ship noise change colour half as quickly. As a result, they don't match the background as closely.

Ship noise also affected the crabs' behaviour. Shore crabs, often found in rock pools, usually stay still or scuttle for cover if a predator approaches, but ship noise disrupted these abilities.

Natural ocean sounds played as loudly as ship noise had no effect on crab camouflage or behaviour, the study found.

"Ship noise is a major source of underwater sound pollution," said Emily Carter, who led the study as part of her MRes at Exeter's Penryn Campus in Cornwall.

"Previous studies have often focussed on how this affects species that rely on sound.

"Shore crabs don't depend heavily on sound - so our finding that noise affects their behaviour and ability to camouflage themselves suggests ship noise might affect a very wide range of species."

The study focussed on juvenile shore crabs, which change colour gradually and can make more dramatic changes when they moult (shedding their shell as they grow).

Professor Martin Stevens, of Exeter's Sensory Ecology and Evolution group, added: "Our study shows that humans and noise pollution can substantially affect features of animals such as their colouration that are crucial to survival.

"If crabs are less well concealed, and less likely to run away, they are more likely to get eaten by predators."

The crabs in the study were housed in one of three tanks, and were exposed either to quiet underwater sounds, an hourly recording of a ship passing (played to simulate the ship being about 200 metres away) or an hourly loud occurrence of underwater sounds.

The crabs were all dark-shelled at the start. After eight weeks in the white-bottomed tanks, all had become paler.

However, those exposed to ship noise only changed around half as much as those in the other tanks, leaving them much less camouflaged.

When exposed to a predator (simulated by an artificial bird) more than 85% of crabs exposed to quiet or loud natural sounds responded by rushing for cover.

The crabs exposed to ship noise responded normally when the noise wasn't being played - but during noise episodes, about half responded more slowly than usual and the other half didn't respond at all.

"The size and strength of adult shore crabs mean they have other defences, but juveniles rely heavily on concealment and are attacked by many predators, from fish to birds - so a reduction in their camouflage ability and anti-predator behaviour could be a big problem," said Carter.

"Previous studies have suggested that a lot of energy may be used during colour change, and stress is also thought to be costly in terms of energy.

"So, the most likely explanation for our findings is that the stress caused by ship noise means crab don't have as much energy to devote to camouflage."

Professor Tom Tregenza, of the University of Exeter, said: "We already knew that noise can be disruptive to marine animals, but a breakthrough from this study is to show that the racket ships make is much more disruptive than natural noise, even if the natural noise is equally loud."

What The Study Did: The risk of physical and sexual violence faced by gay, lesbian, bisexual and questioning U.S. high schoolers was quantified in this observational study that used pooled data from a survey conducted every two years by the Centers for Disease Control and Prevention.

Author: Theodore L. Caputi, M.P.H., of Harvard Medical School, Cambridge Health Alliance in Cambridge, Massachusetts, is the corresponding author.

To access the embargoed study:  Visit our For The Media website at this link https://media.jamanetwork.com/ 

(doi:10.1001/jamapediatrics.2019.6291)

Editor's Note: The article includes funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

A world-first study, led by Australia's Monash University, has patented a new filtration technique that could slash lithium extraction times.

The research team has developed a synthetic MOF-based membrane that can filter lithium ions in an ultra-fast and highly selective manner.

Preliminary studies have shown this technology has a lithium recovery rate of approximately 90 per cent.

An international research team has pioneered and patented a new filtration technique that could one day slash lithium extraction times and change the way the future is powered.

The world-first study, published today in the prestigious international journal Nature Materials, presents findings that demonstrate the way in which Metal-Organic Framework (MOF) channels can mimic the filtering function, or 'ion selectivity', of biological ion channels embedded within a cell membrane.

Inspired by the precise filtering capabilities of a living cell, the research team has developed a synthetic MOF-based ion channel membrane that is precisely tuned, in both size and chemistry, to filter lithium ions in an ultra-fast, one-directional and highly selective manner.

This discovery, developed by researchers at Monash University, CSIRO, the University of Melbourne and the University of Texas at Austin, opens up the possibility to create a revolutionary filtering technology that could substantially change the way in which lithium-from-brine extraction is undertaken.

This technology received a worldwide patent in 2019. Energy Exploration Technologies, Inc. (EnergyX) has since executed a worldwide exclusive licence to commercialise the technology.

"Based on this new research, we could one day have the capability to produce simple filters that will take hours to extract lithium from brine, rather than several months to years," said Professor Huanting Wang, co-lead research author and Professor of Chemical Engineering at Monash University.

"Preliminary studies have shown that this technology has a lithium recovery rate of approximately 90 percent - a substantial improvement on 30 percent recovery rate achieved through the current solar evaporation process."

Professor Benny Freeman from the McKetta Department of Chemical Engineering at The University of Texas at Austin, said: "Thanks to the international, interdisciplinary and collaborative team involved in this research, we are discovering new routes to very selective separation membranes.

"We are both enthusiastic and hopeful that the strategy outlined in this paper will provide a clear roadmap for resource recovery and low energy water purification of many different molecular species."

Associate Professor (Jefferson) Zhe Liu from The University of Melbourne said: "The working mechanism of the new MOF-based filtration membrane is particularly interesting, and is a delicate competition between ion partial dehydration and ion affinitive interaction with the functional groups distributed along the MOF nanochannels.

"There is significant potential of designing our MOF-based membrane systems for different types of filtration applications, including for use in lithium-from-brine extraction."

CSIRO and Monash University Associate Professor Matthew Hill said: "We're pleased that our international research collaboration has made a breakthrough that could improve the supply of lithium. This is important for enabling electric vehicles and grid integration of renewable energy sources."

"It's truly an honour to work with such brilliant scientists at all these organisations," said Teague Egan, Founder and CEO of EnergyX.

"This breakthrough invention will literally change the way lithium is produced and how we power our future."

Lithium-from-brine extraction is most common in the Lithium Triangle - a region of the Andes bordering Argentina, Bolivia and Chile, which holds roughly half of the world's lithium reserves - and some sites across the USA.

With the majority of Australia's lithium produced from the mineral spodumene, the new technique could spur on the investigation of Australia's salt lakes for potential lithium production options.

HOUSTON - (March 9, 2020) - A novel system to amplify gene expression signals could be a game-changer for scientists who study the regulatory processes in cells that are central to all life.

The Rice University lab of bioscientist Laura Segatori has developed a versatile gene signal amplifier that can do a better job of detecting the expression of target genes than current methods.

Ultimately, the researchers hope the two-module system will simplify the diagnosis of diseases like Alzheimer's, diabetes and some cancers characterized by distinctive patterns of protein expression. They said it could also enable cell-based therapies by which diseased cells could make their own medicine at the point of need.

Their work is described in Nature Chemical Biology.

The first module is part of a string of synthetic genetic code added to the DNA of a mammalian cell via CRISPR-Cas9 editing. Once integrated adjacent to a target gene, the code enables a genetic circuit that monitors the gene and, whenever the gene produces a protein, the circuit also emits a green fluorescent protein (GFP). The circuit is designed to amplify the GFP signal and enable detection of very small changes in the target gene that are not always possible with current tools.

When the gene is inactive, the second module based on an antibody first found in camels stops production of the fluorescent protein and degrades any GFPs in the vicinity. The combination gives researchers a strong "on-off" signal that is also sensitive to the dynamics of expression of the target gene. When gene expression increases, the circuit activates expression of GFP and at the same time inhibits expression of negative regulators of GFP, such as the nanobody.

"Being able to monitor gene expression with high sensitivity is really important for a variety of biomedical applications," Segatori said. "It's important to have a detection system that is sensitive to even small changes in gene expression, which are often biologically relevant. It is also critical to a detection system that provides good dynamic resolution so we can follow gene expression dynamics, which are typically a key determinant of cell behavior.

"That's what our gene signal amplifier essentially does," she said. "We developed a genetic circuit that, first of all, we can link to any gene in the chromosome, thus generating a tool that recapitulates the chromosomal context with all the associated complexity of regulation. We don't have any type of extrachromosomal reporters. This approach provides a sensitive way to monitor all the regulatory and epigenetic mechanisms that regulate gene expression.

"Then we developed a method to amplify the signal so we're able to monitor really small changes in expression," she said. "It's very robust and stable and has high dynamic resolution."

The system can be adapted to potentially monitor any cellular gene, Segatori said. "We can create multiplex reporter systems for monitoring group of genes that are relevant to the development of a certain disease or that provide a comprehensive readout for a certain signaling pathway or phenotype," she said.

The team demonstrated the method on a variety of cells and generated a multiplex reporter to monitor markers associated with three signaling pathways that respond to stress in a mammalian cell's endoplasmic reticulum. They found the circuit enhanced the fluorescent signal enough to detect even small changes in expression.

The second module, a NanoDeg circuit introduced by the Rice lab in 2017, is a post-translation control that gives the system its wide dynamic range, Segatori said. "Under basal conditions, the circuit expresses not only a transcriptional regulator that inhibits expression of GFP but also NanoDeg molecules that degrade any GFP present in the system, so the cell goes completely dark," she said. "And we can tune the system to adapt it to detection of genes with different basal expression by using appropriate doses of inducers of the circuit components."

Experiments confirmed that integrating the system into the cell's chromosome does not affect the expression of target genes.

As part of the study, the lab also developed a mathematical model researchers can use to customize the amplifier platform to monitor any target gene and predict the optimal doses of small-molecule inducers used to regulate gene expression.

Segatori and her team are working to enhance the platform, primarily developed by Rice graduate student and lead author Carlos Origel Marmolejo, to treat disease.

"There is a great interest currently in developing cell therapies that are feedback-responsive," Segatori said. "Our platform could allow production of therapeutics in response to detection of gene expression signatures relevant to a certain disease or environmental condition."

PULLMAN, Wash. - A breakthrough into splitting water into its parts could help make renewable energy pay off, even when the sun isn't shining and the wind isn't blowing.

Using solar and wind power when it is available for water splitting, a process that uses electricity to split H2O into hydrogen and oxygen, offers a way to store energy in the form of hydrogen fuel.

Currently the most popular system used for water splitting, or water electrolysis, relies on precious metals as catalysts, but a collaborative research team, including scientists from Los Alamos National Laboratory and Washington State University, has developed a system that uses less expensive and more abundant materials. They describe the advance in a paper published in Nature Energy on March 9.

"The current water electrolysis system uses a very expensive catalyst. In our system, we use a nickel-iron based catalyst, which is much cheaper, but the performance is comparable," said Yu Seung Kim, a research scientist at Los Alamos National Laboratory and corresponding author on the paper.

Most water splitting today is conducted using a piece of equipment called a proton exchange membrane water electrolyzer, which generates hydrogen at a high production rate. It's expensive, and works under very acidic conditions, requiring precious metal catalysts such as platinum and iridium as well as corrosion-resistant metal plates made of titanium.

The research team worked to solve this problem by splitting water under alkaline, or basic, conditions with an anion exchange membrane electrolyzer. This type of electolyzer does not need a catalyst based on precious metals. In fact, a team led by Yuehe Lin, professor at WSU's School of Mechanical and Materials Engineering, created a catalyst based on nickel and iron, elements that are less expensive and more abundant in the environment.

Lin's team shared their development with Kim at Los Alamos, whose team in turn developed the electrode binder to use with the catalyst. The electrode binder is a hydroxide conducting polymer that binds catalysts and provides a high pH environment for fast electrochemical reactions.

The combination of the Los Alamos-developed electrode binder and WSU's catalyst boosted the hydrogen production rate to nearly ten times the rate of previous anion exchange membrane electrolyzers, making it comparable with the more expensive proton exchange membrane electrolyzer.

About 10 million metric tons of hydrogen are currently produced in the United States every year, mostly by using natural gas in a process called natural gas reforming, according to the U.S. Department of Energy. Hydrogen produced from a water splitting process that is powered by electricity from renewable energy holds many economic and environmental benefits, Lin said.

"Water splitting is a clean technology, but you need electricity to do it," said Lin, who is also a corresponding author on the paper. "Now we have a lot of renewable energy, wind and solar power, but it is intermittent. For example, at night we can't use solar, but if during the day, we can use extra energy to convert it into something else, like hydrogen, that's very promising."

The global hydrogen generation market is expected reach $199.1 billion by 2023. Potential markets for hydrogen energy include everything from mass energy conversion and power grid management to fuel cells for cars. Lin estimates that there are approximately 600 wind farms in the United States ready for direct connections to water electrolysis systems.