Quantum leap on film

Jumping electrons: Using a combination of scanning tunneling microscopy and laser spectroscopy with attosecond pulses, Max Planck researchers have filmed electrons in PTCDA molecules arranged next to each other. The position of two molecules are made visible by graphical models. One electron at a time switches back and forth between a higher-energy state and a lower-energy state. The blue coloring stands for a low electron density and the red for a high one. The electron is initially in the energetically higher state. This can be recognized by the relatively high proportion with low electron density (blue). Excited by a laser, it then jumps back and forth between the higher-energy and lower-energy states. The lower-energy state can be recognized by the generally more even distribution of electron density (green, yellow, and orange). After about 1.4 femtoseconds (three images), the electron once again reaches the higher-energy state.
Credit:  Manish Garg / MPI for Solid State Research

An ultra-fast microscope combines atomic spatial and temporal resolution and thus enables unprecedented insights into the dynamics of electrons in molecules

In order to better understand (and possibly control) fast chemical reactions, it is necessary to study the behavior of electrons as precisely as possible – in both space and time. However, up to now, microscopy methods have delivered only either spatially or temporally sharp images. By cleverly combining established techniques of tunneling microscopy and laser spectroscopy, a team led by Klaus Kern, Director at the Max Planck Institute for Solid State Research in Stuttgart, has now overcome these obstacles. Using their atomic quantum microscope, they can make the movement of electrons in individual molecules visible.

It is essential not only for understanding biological processes (e.g. plant photosynthesis) to map the electron dynamics in molecules but also for many technical applications such as the development of solar cells or new types of electronic components. Until now, imaging methods have sometimes delivered images that are difficult to reproduce – or even contradictory. This is because they cannot map the fast electrons directly but rather must resort to techniques that can only reconstruct the behavior of the electrons.

Molecular machine in the nanocontainer

Lars Schäfer from Theoretical Chemistry examined a nanocreis with colleagues from South Korea. Credit: Ruhr University Bochum / Marquard

What a toy: A tiny gyro that has space in a cell and can be controlled from the outside.

The theoretical chemists Dr. have a molecular gyroscope that can be controlled remotely by light. Chandan Das and Prof. Dr. Lars Schäfer from the Ruhr University Bochum (RUB) constructed together with an international team at the Institute for Basic Science in South Korea. In addition, they managed to characterize the rotary movements of this synthetic nanomachine with computer simulations. The authors describe their results in the journal Chem.

Navigation of aircraft or satellites

Machines that are enclosed in a cage or housing can have interesting properties. You can convert any energy supplied into programmed functions. One such system is the mechanical gyroscope. This toy fascinates with its constant rotation. Gyroscopes are also used in practice, for example in navigation systems of aircraft or satellites and in wireless computer mice. "What makes these gyroscopes so advantageous is not only the rotor, but also the housing, which aligns the rotor in a certain direction and protects it from obstacles," says Lars Schäfer.

At the molecular level, many proteins work as biological nanomachines. They are present in every biological cell and perform precise and programmed actions or functions, also within a limited environment. The machines can be controlled by external stimuli. "In the laboratory, the synthesis and characterization of such complex structures and functions in an artificial molecular system is a major challenge," said Schäfer.

Study shows how temperate rainforests can aid the fight against climate change

Fenced livestock enclosures at the edge of oak woodland at Piles Copse where efforts are ongoing to encourage woodland expansion.
Credit: Thomas Murphy University of Plymouth

There is global recognition that woodland expansion could be one of the most effective solutions in the fight against climate change.

However, new research has shown that the level of growth needed to produce the number of trees required by UK targets is unlikely to be achieved through natural means alone.

Environmental scientists and ecologists at the University of Plymouth showed that browsing behavior by livestock is a major determinant of the expansion and connection of fragmented UK upland oak woodlands – so-called ‘temperate rainforests.

The study, focused on Dartmoor in South West England, found the presence of livestock led to far fewer oak saplings surviving. When saplings did survive, they were smaller and in poorer condition, and seldom lived beyond eight years old without protection.

Interestingly, however, disturbance by grazing livestock may not be all bad and its precise impact may depend on surrounding plant species.

Individuals with immunodeficiency at high risk of mortality following SARS-CoV-2 infection

Patients with primary and secondary immunodeficiency are at higher risk of mortality following SARS-CoV-2 infection compared with the general population, according to a new study led by the University of Birmingham.

The COVID-19 pandemic has disproportionately affected individuals with primary immunodeficiency (PID) and secondary immunodeficiency (SID). These conditions arise when the immune system’s ability to fight infectious disease is compromised or entirely absent as a result of genetic mutations (PID) or other factors, such as immunosuppressive drugs, blood cancers or chemotherapy (SID).

In a significant national effort, and the largest study of its kind to date, the United Kingdom Primary Immunodeficiency Network (UKPIN) collated the outcomes of individuals with PID and SID following infection and treatment for COVID-19.

This retrospective study, published in the journal Clinical & Experimental Immunology, aims to better understand the risk of severe disease and death following SARS-CoV-2 infection in patients with primary or secondary immunodeficiency. The outcomes of 310 individuals from across the United Kingdom were reported to a UKPIN case series between March 2020 and July 2021.

The team found that 45.8% of patients with PID or SID were hospitalized with COVID-19, a significantly higher rate than for the UK general population, and died up to 26 years younger than the median age of death from COVID-19 in the UK. The risk of dying in patients with primary or secondary immunodeficiency was also higher than the general population, varying between subgroups of these conditions. For example, 16.3% of individuals with primary immunodeficiency receiving immunoglobulin replacement and 27.2% with secondary immunodeficiency died from infection during the first three waves of the SARS-CoV-2 pandemic in the UK.

Hubble Captures Chameleon Cloud I

Image Credit: NASA, ESA, K. Luhman and T. Esplin (Pennsylvania State University), et al., and ESO; Processing: Gladys Kober (NASA/Catholic University of America)
Hi-Res Zoomable Image

This NASA Hubble Space Telescope image captures one of three segments that comprise a 65-light-year wide star-forming region named the Chamaeleon Cloud Complex. The segment in this Hubble composite image, called Chamaeleon Cloud I (Cha I), reveals dusty-dark clouds where stars are forming, dazzling reflection nebulae glowing by the light of bright-blue young stars, and radiant knots called Herbig-Haro objects.

Herbig-Haro objects are bright clumps and arcs of interstellar gas shocked and energized by jets expelled from infant “protostars” in the process of forming. The white-orange cloud at the bottom of the image hosts one of these protostars at its center. Its brilliant white jets of hot gas are ejected in narrow torrents from the protostar’s poles, creating the Herbig-Haro object HH 909A.

Modern Day Gold Rush Turns Pristine Rainforests into Heavily Polluted Mercury Sinks

Illegal gold miners use mercury to bind gold particles, then separate the two metals by burning gold-mercury pellets in open fire ovens, releasing clouds of highly toxic mercury particles into the atmosphere.
Credit – Melissa Marchese

If you had to guess which part of the world has the highest levels of atmospheric mercury pollution, you probably wouldn’t pick a patch of pristine Amazonian rainforest. Yet, that’s exactly where they are.

In a new study appearing in the journal Nature Communications, an international team of researchers show that illegal gold mining in the Peruvian Amazon is causing exceptionally high levels of atmospheric mercury pollution in the nearby Los Amigos Biological Station.

One stand of old-growth pristine forest was found to harbor the highest levels of mercury ever recorded, rivaling industrial areas where mercury is mined. Birds from this area have up to twelve times more mercury in their systems than birds from less polluted areas.

The spread of mercury pollution from gold mining has primarily been studied in aquatic systems. In this study, a team of researchers led by Jacqueline Gerson, who completed this research as part of her Ph.D. at Duke, and Emily Bernhardt, professor of Biology, provide the first measurements of terrestrial inputs, storage and impact of atmospheric mercury to forests and measurements of methylmercury, the most toxic form of mercury.

Illegal miners separate gold particles from river sediments using mercury, which binds to gold, forming pellets large enough to be caught in a sieve. Atmospheric mercury is released when these pellets are burned in open fire ovens. The high temperature separates the gold, which melts, from the mercury, which goes up in smoke. This mercury smoke ends up being washed into the soil by rainfall, deposited onto the surface of leaves, or absorbed directly into the leaves’ tissues.

Thawing permafrost can accelerate global warming

Outcrop of Yedoma sediments with the thick ice masses underlain by river sediments exposed on an arm of the Lena River in the river delta.
Credit: Janet Rethemeyer

Thawing permafrost in the Arctic could be emitting greenhouse gases from previously unaccounted-for carbon stocks, fueling global warming. That is the result of a study conducted by a team of geologists led by Professor Dr Janet Rethemeyer at the University of Cologne’s Institute of Geology and Mineralogy, together with colleagues from the University of Hamburg and the Helmholtz Centre Potsdam – GFZ German Research Centre for Geosciences. In the Siberian Arctic, the research team determined the origin of carbon dioxide released from permafrost that is thousands of years old. This research endeavor is part of the German-Russian research endeavor ‘Kopf – Kohlenstoff im Permafrost’, funded by the German Federal Ministry of Education and Research (BMBF). The paper ‘Sources of CO2 Produced in Freshly Thawed Pleistocene-Age Yedoma Permafrost’ has now appeared in Frontiers in Earth Science.

Global climate change is causing temperatures to rise sharply, especially in the Arctic. Among other things, higher temperatures are causing more and more permafrost soils, which have been frozen for thousands of years, to thaw. Particularly affected is so-called ‘yedoma’ permafrost, which is widespread in areas that were not covered by ice sheets during the last ice age. Yedoma contains up to 80 per cent ice and is therefore also called ice complex. The ground ice can thaw very abruptly, causing the bedrock to collapse and erode. Such processes, known as thermokarst, make carbon previously stored in the frozen ground accessible to microorganisms, which break it down and release it as carbon dioxide and methane. The greenhouse gas release amplifies global warming, which is known as permafrost-carbon feedback.

New species of 'incredibly rare' insect discovered

The newly discovered leafhopper Phlogis kibalensis
Credit: Dr Alvin Helden, Anglia Ruskin University 

An Anglia Ruskin University (ARU) scientist has discovered a new species that belongs to a group of insects so rare that its closest relative was last seen in 1969.

Dr Alvin Helden found the new species of leafhopper, which he has named Phlogis kibalensis, during field work with students in the rainforest of the Kibale National Park in western Uganda, and the discovery has been announced in the journal Zootaxa.

The new species, which has a distinctive metallic sheen, pitted body, and, in common with most leafhoppers, uniquely-shaped male reproductive organs – in this case partially leaf-shaped – belongs to a group, or genus, called Phlogis.

Prior to this new discovery, the last recorded sighting of a leafhopper from this rare genus was in Central African Republic in 1969.

A 3D View of an Atmospheric River

Features in Earth’s atmosphere, spawned by the heat of the Sun and the rotation of the Earth, transport water and energy around the globe. Clouds and precipitation shown here are from NASA’s MERRA-2 reanalysis, a retrospective blend of a weather model and conventional and satellite observations.

Video: NASA's Scientific Visualization Studio
Final Editing and Conversion: Scientific Frontline

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Invisible machine-readable labels that identify and track objects

Caption:MIT scientists built a user interface that facilitates the integration of common tags (QR codes or ArUco markers used for augmented reality) with the object geometry to make them 3D printable as InfraredTags.
Credits: Photos courtesy of MIT CSAIL.

If you download music online, you can get accompanying information embedded into the digital file that might tell you the name of the song, its genre, the featured artists on a given track, the composer, and the producer. Similarly, if you download a digital photo, you can obtain information that may include the time, date, and location at which the picture was taken. That led Mustafa Doga Dogan to wonder whether engineers could do something similar for physical objects. “That way,” he mused, “we could inform ourselves faster and more reliably while walking around in a store or museum or library.”

The idea, at first, was a bit abstract for Dogan, a 4th-year PhD student in the MIT Department of Electrical Engineering and Computer Science. But his thinking solidified in the latter part of 2020 when he heard about a new smartphone model with a camera that utilizes the infrared (IR) range of the electromagnetic spectrum that the naked eye can’t perceive. IR light, moreover, has a unique ability to see through certain materials that are opaque to visible light. It occurred to Dogan that this feature, in particular, could be useful.