Self-assembly of complex systems: hexagonal building blocks are better

Professor Erwin Frey
Photo Credit: © Benjamin Asher / Ludwig-Maximilians-Universität München

Complex systems in nature, like their synthetic counterparts in technology, comprise a large number of small components that assemble of their own accord through molecular interactions. Gaining a better understanding of the principles and mechanisms of this self-assembly is important for the development of new applications in domains such as nanotechnology and medicine.

Professor Erwin Frey, Chair of Statistical and Biological Physics at LMU and member of the ORIGINS Excellence Cluster, and his research fellow Dr. Florian Gartner has now investigated an aspect of self-assembly that has received little attention before now: What role do the shape and the number of possible bonds between particles play? As the researchers report in the journal Physical Review X, their results show that hexagonal morphologies – in other words, six-sided structures – such as molecules with six binding sites are ideal for self-assembly.

Drug shows promise for slowing progression of rare, painful genetic disease

A CT angiography scan of a person with ACDC disease showing abnormal calcification of the blood vessels in the legs and feet.
Image Credit: Courtesy of National Institutes of Health

A drug used to treat certain bone diseases shows promise for slowing the progression of a rare, painful genetic condition that causes excessive calcium buildup in the arteries, known as arterial calcification due to deficiency of CD73 (ACDC). These results are from a first-in-human clinical trial supported by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health. The study, published in the journal Vascular Medicine, could lead to the first effective treatment for the rare disease.

ACDC, which has no known cure, often targets the arteries of the legs and can make walking painful and difficult. It can also affect the joints of the hands, causing pain and deformities. In severe cases, the condition can lead to potential limb loss. Symptoms of the disease often begin in the late teens and 20s. An extremely rare disease, it is believed to affect only about 20 people worldwide and has an estimated prevalence of less than 1 in 1 million. Previous studies have identified the gene for ACDC disease and the biochemical mechanism behind it. More recent studies by the NHLBI research team identified an existing drug, called etidronate, as a potential treatment for ACDC based on disease models in animals and human cells.

Pressure determines which embryonic cells become ‘organizers’

 Tooth epithelium (cell surface; yellow) and mesenchyme (cell surface; magenta). Proliferating cells (cyan) expand the tissue, generating a mechanical pressure at the tissue center that drives the formation of the main tooth signaling center or organizer, the enamel knot.
Photo Credit Neha Pincha Shroff and Pengfei Xu

A collaboration between research groups at the University of California, TU Dresden in Germany and Cedars-Sinai Guerin Children’s in Los Angeles has identified a mechanism by which embryonic cells organize themselves to send signals to surrounding cells, telling them where to go and what to do. While these signaling centers have been known to science for a while, how individual cells turn into organizers has been something of a mystery.

Until now. In a paper published in the journal Nature Cell Biology, the researchers find that cells are literally pressed into becoming organizers.

“We were able to use microdroplet techniques to figure out how the buildup of mechanical pressure affects organ formation,” said co-corresponding author Otger Campàs, former associate professor of mechanical engineering at UC Santa Barbara, who is currently managing director, professor and chair of tissue dynamics at the Physics of Life Excellence Cluster of TU Dresden.

Discovery could end global amphibian pandemic

Panamanian golden frog
Photo Credit: Brian Gratwicke/U.S. Fish & Wildlife Service

A fungus devastating frogs and toads on nearly every continent may have an Achilles heel. Scientists have discovered a virus that infects the fungus, and that could be engineered to save the amphibians.

The fungus, Batrachochytrium dendrobatidis or Bd, ravages the skin of frogs and toads, and eventually causes heart failure. To date it has contributed to the decline of over 500 amphibian species, and 90 possible extinctions including yellow-legged mountain frogs in the Sierras and the Panamanian golden frog. 

A new paper in the journal Current Biology documents the discovery of a virus that infects Bd, and which could be engineered to control the fungal disease.

The UC Riverside researchers who found the virus are excited about the implications of their discovery. In addition to helping them learn about how fungal pathogens rise and spread, it offers the hope of ending what they call a global amphibian pandemic. 

“Frogs control bad insects, crop pests, and mosquitoes. If their populations all over the world collapse, it could be devastating,” said UCR microbiology doctoral student and paper author Mark Yacoub. 

“They’re also the canary in the coal mine of climate change. As temperatures get warmer, UV light gets stronger, and water quality gets worse, frogs respond to that. If they get wiped out, we lose an important environmental signal,” Yacoub said. 

Pollen is a promising sustainable tool in the bone regeneration process

Scientists have used pollen to grow hydroxyapatite capsules, so the mineral can better support bone regeneration
Photo Credit: Alex Jones

A study has shown pollen grains can be used as green templates for producing biomaterials, showcasing their potential to support drug delivery and bone regeneration.

With an increasingly ageing population, bone fractures are becoming more common. Bone is generally able to self-repair but if the fracture is too big or the person affected too fragile, as for example people with osteoporosis, the use of bone fillers can help.

Hydroxyapatite (HAp) is an inorganic mineral present in human bone and teeth, which can be used to support bone regeneration. It makes up somewhere between 65 per cent and 70 per cent of the weight of human bone. Healthcare professionals often use synthetic and natural HAp when carrying out bone repair treatments.

A team at the University of Portsmouth has worked with international colleagues to explore sustainable ways to improve the process. 

They examined the feasibility of using pollen grains as bio-templates for growing calcium phosphate minerals in the lab - particularly hydroxyapatite (HAp) and β-tricalcium phosphate (TCP), which are types of calcium phosphate used for bone repair.

Kapitza-Dirac effect used to show temporal evolution of electron waves

Time dependent interference fringes from the ultrafast Kapitza Dirac Effect. An electron wave packet is exposed to two counterpropagating ultrashort laser pulses. The time span from back to front is 10 pico seconds.
Illustration Credit: © Goethe University Frankfurt

One of the most fundamental interactions in physics is that of electrons and light. In an experiment at Goethe University Frankfurt, scientists have now managed to observe what is known as the Kapitza-Dirac effect for the first time in full temporal resolution. This effect was first postulated over 90 years ago, but only now are its finest details coming to light. 

It was one of the biggest surprises in the history of science: In the early days of quantum physics around 100 years ago, scholars discovered that the particles which make up our matter always behave like waves. Just as light can scatter at a double slit and produce scattering patterns, electrons can also display interference effects. In 1933, the two theorists Piotr Kapitza and Paul Dirac proved that an electron beam is even diffracted from a standing light wave (due to the particles' properties) and that interference effects as a result of the wave properties are to be expected. 

A German-Chinese team led by Professor Reinhard Dörner from Goethe University Frankfurt has succeeded in using this Kapitza-Dirac effect to visualize even the temporal evolution of the electron waves, known as the electrons' quantum mechanical phase. The researchers have now presented their results in the journal Science. 

In the evolution of walking, the hip bone connected to the rib bones

New reconstruction of the skeleton of Tiktaalik roseae, a 375-million-year-old fossil fish. In a new study, researchers used micro-CT imaging to reveal vertebrae and ribs of the fish that were previously hidden beneath rock. The new reconstruction shows that the fish’s ribs likely attached to its pelvis, an innovation thought to be crucial to supporting the body and for the eventual evolution of walking.
Photo Credit: Thomas Stewart / Pennsylvania State University
(CC BY-NC-ND 4.0 DEED)

Before the evolution of legs from fins, the axial skeleton — including the bones of the head, neck, back and ribs — was already going through changes that would eventually help our ancestors support their bodies to walk on land. A research team including a Penn State biologist completed a new reconstruction of the skeleton of Tiktaalik, the 375-million-year-old fossil fish that is one of the closest relatives to limbed vertebrates. The new reconstruction shows that the fish’s ribs were likely attached to its pelvis, an innovation thought to be crucial to supporting the body and for the eventual evolution of walking.

A paper describing the new reconstruction, which used microcomputed tomography (micro-CT) to scan the fossil and reveal vertebrae and ribs of the fish that were previously hidden beneath rock, appeared in the journal Proceedings of the National Academy of Sciences.

“Tiktaalik was discovered in 2004, but key parts of its skeleton were unknown,” said Tom Stewart, assistant professor of biology in the Eberly College of Science at Penn State and one of the leaders of the research team. “These new high-resolution micro-CT scans show us the vertebrae and ribs of Tiktaalik and allow us to make a full reconstruction of its skeleton, which is vital to understanding how it moved through the world.”

Repurposed Cancer Drugs May Improve Tuberculosis Treatment

Mycobacterium tuberculosis bacteria.
Image Credit: NIAID, NIH

Researchers have identified a combination of existing cancer drugs that may improve treatment for tuberculosis.

In a study conducted in rabbits and led by Harvard Medical School researchers at Massachusetts General Hospital, the repurposed drugs enhanced delivery of antibacterial medications that target tuberculosis-causing bacteria.

Although it is often overlooked in industrialized countries such as the United States, tuberculosis remains one of the deadliest diseases globally, causing millions of deaths every year.

Sometimes, patients die even after being treated, either because tuberculosis bacteria develop resistance to antibacterial drugs or because the ability to deliver medications to infected lung tissue is poor.

To address the latter challenge, researchers repurposed a pair of cancer drugs already approved by the U.S. Food and Drug Administration. The drugs were originally designed to enhance drug delivery to cancer cells by improving the structure and function of blood vessels around tumors, which can be compromised in cancer.

Research Finds Dairy Farmers Receptive to Methane-Reducing Seaweed Feed

New research led by the University of New Hampshire examines the receptiveness of organic dairy farmers across Maine to pay an average of 64 cents more per cow per day to use methane-reducing seaweed-based feed to their cows, similar to those shown here.
Photo Credit: University of New Hampshire

New England’s dairy industry continues to evolve in response to significant market challenges that include a decreased demand for milk and higher production and land costs. However, there is also ongoing evidence that organic dairy farming can provide environmental benefits — such as reducing methane emissions — which could further differentiate their products as well as help qualify farms for new government initiatives to reduce methane through innovative management practices. Researchers from the University of New Hampshire collaborated with researchers in Maine to find evidence that nearly half of organic dairy farmers would be willing to pay a little extra for methane-reducing seaweed feed but would only consider if it was cost effective, aligned with existing feeding practices and would qualify them for government policies and subsidies.     

“Dairy farmers aim to run their farms as lucrative enterprises,” said Andre Brito, associate professor of dairy cattle nutrition and management and a scientist at UNH’s New Hampshire Agricultural Experiment Station. “The additional cost would require serious considerations, as well as more data and an effective implementation of carbon markets in the future.” 

Scientists release new insight about Southern Ring Nebula

The Southern Ring Nebula, or NGC 3132, was one of the first objects observed by the James Webb Space Telescope.
Image Credit: NASA/ESA/CSA/STScI  

Planetary nebulae have been studied for centuries, but astronomers are getting new looks and a better understanding of the structures and compositions of these gaseous remnants of dying stars thanks to the ability to study objects at multiple wavelengths and dimensions.

The Southern Ring Nebula, or NGC 3132, is one such object. Rochester Institute of Technology Chester F. Carlson Center for Imaging Science and School of Physics and Astronomy Professor Joel Kastner and his team used Submillimeter Array (SMA) mapping to take a closer look at the nebula, which was one of the first cosmic objects observed by the James Webb Space Telescope soon after its deployment in 2022. The researchers found that most of the molecular gas in the nebula actually lies in an enormous, expanding ring, and further, that the nebula has a second, nearly perpendicular, expanding ring. The research findings were recently published in The Astrophysical Journal. Kastner is the founding director of RIT’s Laboratory for Multiwavelength Astrophysics.

Inspired by the JWST infrared images, which dramatically reveal how hydrogen gas in molecular form threads through the Southern Ring, Kastner and the team used SMA radio-wavelength mapping to measure both the distribution on the sky and the precise velocities of carbon monoxide gas in the nebula. The measurements establish which regions of the Southern Ring Nebula are moving toward and away from us, revealing the two rings. The team’s new SMA results support previous findings that the nebula’s present form is the result of interactions between the dying star and one or possibly two companion stars.