Thermal motions and oscillation modes determine the uptake of bacteria in cells

Photo of a membrane bubble with different oscillation modes in the background and experimental scheme in the foreground. Optical tweezers (laser focus in red) bring a thermally fluctuating particle into contact with a membrane bubble (green) until the particle is invaginated into the membrane and taken up.
Graphic Credit: AG Rohrbach

How and with what effort does a bacterium - or a virus - enter a cell and cause an infection? Researchers from Freiburg have now made an important contribution to answering this question: A team led by physicist Prof. Dr. Alexander Rohrbach and his collaborator Dr. Yareni Ayala was able to show how thermal fluctuations of a model bacterium and membrane oscillation modes of a model cell influence the energy with which the model bacteria dock and enter the membrane. The results have just been published in the journal Nature Communications.

Like a sticky piece of candy on a wobbly balloon

“To understand how a bacterium or virus enters a cell, you can imagine a sticky candy on a floppy, wobbly balloon. When a child shakes the rubber balloon around, the candy sticks even tighter to its surface,” said Rohrbach, a professor of -Bio- and Nano-Photonics at the Department of Microsystems Engineering at the University of Freiburg. In his lab, the laser and bio-physicists set up a similar experiment to study the physics of infection processes. The wobbly balloon corresponds to a giant uni-lamellar vesicle (GUV), which serves as a biological model cell. The membrane vesicle is the size of a tiny grain of sand about 20 micrometers in diameter.

COVID-19 conspiracy theories that spread fastest focused on evil, secrecy

Covid 19 Conspiracy Initiated
Image Credit: Dr StClaire

In the early pandemic, conspiracy theories that were shared the most on Twitter highlighted malicious purposes and secretive actions of supposed bad actors behind the crisis, according to an analysis of nearly 400,000 posts. 

In the study, researchers identified commonalities in five of the most popular conspiracy theories: those related to Bill Gates, 5G Networks, vaccinations, QAnon and Agenda 21.

While each theory appears to have a different subject, the social media narratives often overlapped, said Porismita Borah, associate professor in Washington State University’s Murrow College of Communications.

“The conspiracy theories might be using different strategies, but the narratives are often connected,” said Borah, the corresponding author on the study published in the journal New Media and Society. “These theories have a lot in common in that they try to make the stories part of a bigger conspiracy so that if people believe in one conspiracy, then they tend to believe in the other.”

Spinning food processing waste into ‘gold’

Among the waste types analyzed in the study was fried donut waste, a potential candidate for anaerobic fermentation to biogas.
Photo Credit: Pexels

There is money to be made – and potential to reduce greenhouse gas emissions – by finding a second life for the potato peels, fried dough particles, cheese whey and other industrial food-processing waste products that routinely end up in landfills, according to new research.

Scientists have taken the first step at estimating the best large-scale uses for food processing waste, first analyzing its contents and, based on those findings, proposing production opportunities ranging from sustainable fuels, biogas and electricity to useful chemicals and organic fertilizer.

This work is known as valorization, or determining the potential value of something “that is otherwise valueless or even a drain on resources for a company – when you have to spend money to get rid of it,” said Katrina Cornish, senior author of the study and professor of horticulture and crop science and food, agricultural and biological engineering at The Ohio State University. 

“The bioeconomy is becoming much more prevalent as a topic of conversation. In this case, don’t get rid of food waste – make some money from it,” said Cornish, also an Ohio Research Scholar of Bio-Emergent Materials. “Here, we’re putting the base model in place for food manufacturers who are wondering, ‘What can I do with this stuff?’ Our flow chart guides them in a specific direction and prevents them from wasting time trying something we know won’t work.” 

Wolves eliminate deer on Alaskan Island then quickly shift to eating sea otters

Wolves on an Alaskan island caused a deer population to plummet and switched to primarily eating sea otters in just a few years, a finding scientists at Oregon State University and the Alaska Department of Fish and Game believe is the first case of sea otters becoming the primary food source for a land-based predator.

Using methods such as tracking the wolves with GPS collars and analyzing their scat, the researchers found that in 2015 deer were the primary food of the wolves, representing 75% of their diet, while sea otters comprised 25%. By 2017, wolves transitioned to primarily consuming sea otters (57% of their diet) while the frequency of deer declined to 7%. That pattern held through 2020, the end of the study period.

“Sea otters are this famous predator in the near-shore ecosystem and wolves are one of the most famous apex predators in terrestrial systems,” said Taal Levi, an associate professor at Oregon State. “So, it’s pretty surprising that sea otters have become the most important resource feeding wolves. You have top predators feeding on a top predator.”

No link between IVF-assisted conception and school-age childhood development outcomes

Researchers say the study offers important reassurance for clinicians and families.
Photo Credit: Yan Krukau

A comprehensive study of more than 400,000 children - with over 11,000 conceived via in-vitro fertilization (IVF) - has found no link between IVF conception and adverse developmental outcomes for school-age children.

Published today in PLOS Medicine, the study involved collaboration between the three major IVF units in Victoria - Melbourne IVF, Monash IVF and City Fertility Centre, and incorporated data on over 400,000 children born between 2005 and 2013, 11,059 of whom were conceived via IVF.

Led by Dr Amber Kennedy and Dr Anthea Lindquist, the study assessed childhood developmental and educational outcomes using the Australian Early Development Census (AEDC) and the National Assessment Program for Literacy and Numeracy (NAPLAN).

Dr Kennedy said: “We found no difference in performance across the five domains of the AEDC, nor in NAPLAN scores, between children who were born after IVF-assisted conception and those who were conceived without assistance.

Fish sensory organ key to improving navigational skills of underwater robots

Yellow blaze African cichlid
Photo Credit: Sarah Page

Scientists, led by the University of Bristol, have been studying a fish sensory organ to understand cues for collective behavior which could be employed on underwater robots.

This work was centered around the lateral line sensing organ in African cichlid fish, but found in almost all fish species, that enables them to sense and interpret water pressures around them with enough acuity to detect external influences such as neighboring fish, changes in water flow, predators and obstacles.

The lateral line system as a whole is distributed over the head, trunk and tail of the fish. It is comprised of mechanoreceptors (neuromasts) that are either within subdermal channels or on the surface of the skin.

Lead author Elliott Scott of the University of Bristol’s Department of Engineering Mathematics explained: “We were attempting to find out if the different areas of the lateral line - the lateral line on the head versus the lateral line on the body, or the different types of lateral line sensory units such as those on the skin, versus those under it, play different roles in how the fish is able to sense its environment through environmental pressure readings.

Interfering in big decisions friends and family take could violate a crucial moral right, philosopher argues

Two people speaking, sat at a table 
Photo Credit: Charles Deluvio

If you’ve told an adult friend or family member that they should not take a job, not date someone, not try skydiving or not move abroad, you may have violated a crucial moral right to ‘revelatory autonomy’ and ‘self-authorship’, according to a philosopher at Christ’s College, Cambridge.

Dr Farbod Akhlaghi’s study, published in the journal Analysis, is the first of its kind to suggest that we have a moral right to ‘revelatory autonomy’, that is the right to discover for ourselves who we’ll become as a result of making ‘transformative choices’, choices to have experiences that teach us what that experience will be like for us whilst also changing our core preferences, values and desires.

Dr Akhlaghi says: “The ability to see that the person we’ve become is the product of decisions that we made for ourselves is very important.

“I’m not telling people what to do. I’m just highlighting part of what is morally at stake in these very common interactions and trying to develop a framework for us to understand them. I hope some may find this helpful, as these will always be difficult moments for all of us.”

Global study of hypoxia in rivers shows it is more prevalent than previously thought

High-frequency sensors deployed in streams, such as those being installed by Joanna Blaszczak in a stream in Montana, can provide continuous data that captures night-time hypoxic conditions.
Photo Credit: Malgosia Blaszczak.

New research led by University of Nevada, Reno Assistant Professor Joanna Blaszczak shows hypoxia in rivers and streams is generally much more prevalent across the globe than previously thought. Hypoxia is low or depleted oxygen levels in surface waters that can be harmful to aquatic species and can in some cases increase production of harmful greenhouse gases from rivers.

The research, published recently in the journal Limnology and Oceanography Letters, compiles over 118 million readings of dissolved oxygen and temperature taken from over 125,000 locations in rivers across six continents and 93 countries and spanning over 100 years, from 1900 to 2018. Hypoxia, defined in this study as dissolved oxygen concentrations below 2 milligrams per liter, was detected in rivers and streams in 53 countries, with 12.6% of all locations exhibiting at least one hypoxic measurement.

“Hypoxia in coastal waters and lakes is widely recognized as a detrimental environmental issue, yet we have lacked a comparable understanding of hypoxia in rivers,” Blaszczak, with the University’s College of Agriculture, Biotechnology & Natural Resources, said. “While 12.6% might not seem like a huge percentage, previously it was generally thought that occurrences of hypoxia in rivers and streams were exceedingly rare. Having shown presence of hypoxia in one of every eight river locations with data is definitely a game changer in terms of how we need to think of and give attention to the issue of hypoxia in rivers and streams.”

Lockheed Martin Announces Successful First Flight Of F-16 Block 70 Aircraft

F-16 Block 70 first flight
Photo Credit: Lockheed Martin Corporation

Lockheed Martin today announced the successful first flight of the F-16 Block 70 at its Greenville, South Carolina site. 

The flight occurred Jan. 24 at 9:17 a.m. ET, with Lockheed Martin test pilots Dwayne "Pro" Opella and Monessa "Siren" Balzhiser at the helm. Total flight time was approximately 50 minutes and included airworthiness checks, such as engine, flight control and fuel system checks, as well as basic aircraft handling. 

"Today's successful flight is a testament of the hard work, dedication and commitment to our customers and their missions," said OJ Sanchez, vice president, Integrated Fighter Group, which includes the F-16 program. "This milestone demonstrates Lockheed Martin's commitment to advancing this program and getting this much-needed aircraft and its advanced 21st Century Security capabilities to the warfighter."

This F-16 Block 70 jet is the first of 16 jets to be delivered to Bahrain. Six countries have selected Block 70/72 aircraft. In addition to the current official backlog of 128 jets to-date to be built in Greenville, Jordan last year signed a Letter of Offer and Acceptance (LOA) for eight jets and last week signed an additional LOA for four more jets. Lockheed Martin has received a contract to begin Jordan's long-lead activities. Bulgaria has also signed an LOA for an additional eight jets for its fleet. Once these are finalized, the backlog will increase to 148.

Plasma thrusters used on satellites could be much more powerful

The chamber where prof. Benjamin Jorns’ team tests the new Hall plasma thruster at the PEPL lab on the University of Michigan’s North Campus.
Photo Credit: Marcin Szczepanski/Lead Multimedia Storyteller, University of Michigan College of Engineering

It was believed that running more propellant through a Hall thruster would wreck its efficiency, but new experiments suggest they might power a crewed mission to Mars

It was believed that Hall thrusters, an efficient kind of electric propulsion widely used in orbit, need to be large to produce a lot of thrust. Now, a new study from the University of Michigan suggests that smaller Hall thrusters can generate much more thrust—potentially making them candidates for interplanetary missions.

“People had previously thought that you could only push a certain amount of current through a thruster area, which in turn translates directly into how much force or thrust you can generate per unit area,” said Benjamin Jorns, U-M associate professor of aerospace engineering who led the new Hall thruster study to be presented at the AIAA SciTech Forum in National Harbor, Maryland, today.