Their study titled “Network Connectivity Changes Following Long-Term Cocaine Use and Abstinence,” was highlighted by the editor of Journal of Neuroscience in “This Week in The Journal.” The findings show that continued cocaine use affects how crucial neural networks communicate with one another in the brain, including the default mode network (DMN), the salience network (SN), and the lateral cortical network (LCN).

“The disrupted communication between the DMN and SN can make it harder to focus, control impulses, or feel motivated without the drug,” said Li-Ming Hsu, PhD, assistant professor of radiology and lead author on the study. “Essentially, these changes can impact how well they respond to everyday situations, making recovery and resisting cravings more challenging.”

Hsu led this project during his postdoctoral tenure at the Center for Animal MRI in the Biomedical Research Imaging Center and the Department of Neurology. The work provides new insights into the brain processes that underlie cocaine addiction and creates opportunities for the development of therapeutic approaches and the identification of an imaging marker for cocaine use disorders.

The brain operates like an orchestra, where each instrumentalist has a special role crucial for creating a coherent piece of music. Specific parts of the brain need to work together to complete a task. The DMN is active during daydreams and reflections, the SN is crucial for attentiveness, and the CEN, much like a musical conductor, plays a role in our decision-making and problem-solving.

The research was motivated by observations from human functional brain imaging studies suggesting chronic cocaine use alters connectivity within and between the major brain networks. Researchers needed a longitudinal animal model to understand the relationship between brain connectivity and the development of cocaine dependence, as well as changes during abstinence.

Researchers employed a rat model to mimic human addiction patterns, allowing the models to self-dose by nose poke. Paired with advanced neuroimaging techniques, the behavioral approach enables a deeper understanding of the brain’s adaptation to prolonged drug use and highlights how addictive substances can alter the functioning of critical brain networks.

Hsu’s research team used functional MRI scans to explore the changes in brain network dynamics on models that self-administrated cocaine. Over a period of 10 days followed by abstinence, researchers observed significant alterations in network communication, particularly between the DMN and SN.

These changes were more pronounced with increased cocaine intake over the 10 days of self-administration, suggesting a potential target for reducing cocaine cravings and aiding those in recovery. The changes in these networks’ communication could also serve as useful imaging biomarkers for cocaine addiction.

The study also offered novel insights into the anterior insular cortex (AI) and retrosplenial cortex (RSC). The former is responsible for emotional and social processing; whereas, the latter controls episodic memory, navigation, and imagining future events. Researchers noted that there was a difference in coactivity between these two regions before and after cocaine intake. This circuit could be a potential target for modulating associated behavioral changes in cocaine use disorders.

“Prior studies have demonstrated functional connectivity changes with cocaine exposure; however, the detailed longitudinal analysis of specific brain network changes, especially between the anterior insular cortex (AI) and retrosplenial cortex (RSC), before and after cocaine self-administration, and following extended abstinence, provides new insights,” said Hsu.

Scientists from Tohoku University have investigated whether the early atmospheric conditions on Mars had the potential to foster the formation of biomolecules — organic compounds essential for biological processes. Their findings, published in Scientific Reports, offer intriguing insights into the plausibility of Mars harboring life in its distant past.

Today, Mars presents a harsh environment characterized by dryness and extreme cold, but geological evidence hints at a more hospitable past. About 3.8-3.6 billion years ago, the planet probably had a temperate climate, sustained by the warming properties of gases like hydrogen. In such an environment, Mars may have had liquid water, a key ingredient for life as we know it.

The researchers investigated whether formaldehyde could have formed in the early Martian environment. Formaldehyde is a simple organic compound that plays a crucial role as a precursor for the formation of vital biomolecules through purely chemical or physical processes. These biomolecules, like amino acids and sugars, serve as the fundamental building blocks for proteins and RNA, essential components of life.

Using an advanced computer model, the team simulated the potential atmospheric composition of early Mars to explore the potential for formaldehyde production. The model was built with the assumption that the atmosphere was rich in carbon dioxide, hydrogen, and carbon monoxide. Their simulations suggest that the ancient Martian atmosphere could have provided a continuous supply of formaldehyde which would have potentially led to the creation of various organic compounds. This raises the intriguing possibility that the organic materials detected on the Martian surface could have originated from atmospheric sources, particularly during the planet’s two earliest geological periods.

“Our research provides crucial insights into the chemical processes that may have occurred on ancient Mars, offering valuable clues to the possibility of past life on the planet,” says Shungo Koyama, lead author of the study. By revealing that there were conditions favorable for the formation of bio molecules, the research broadens our understanding of the planet’s ancient capacity to sustain life.

Next, the team plans to analyze geological data gathered by NASA’s Martian rovers, with the aim of increasing their understanding of organic materials present early in the planet’s history. By comparing the expected carbon isotopes of ancient formaldehyde with data from Martian samples, they hope to get a better picture of the processes that shaped the planet’s organic chemistry

Traditional industrial production of H₂O₂ via the anthraquinone process using hydrogen and oxygen, is highly energy-intensive. This approach employs toxic solvents and expensive noble-metal catalysts, and generates substantial waste from side reactions. In contrast, photocatalytic production of H₂O₂ from oxygen and water offers an energy-efficient, mild and clean route. Most importantly, it addresses the common drawbacks of existing photocatalytic systems, such as low activity, heavy use of additional alcohol sacrificial donors, and the necessity for pure oxygen gas input.

A research team led by Professor JIANG Donglin from the NUS Department of Chemistry has developed a new type of photocatalyst for the efficient artificial photosynthesis of H₂O₂ from water and air. The researchers constructed hexavalent covalent organic frameworks (COFs) in which the skeleton is designed to be donor-acceptor π columns for high-rate photo-induced charge generation and catalytic active sites. In parallel, the pore is engineered with hydraulically sensitivetrigonal microporous channels for immediate delivery of reactants water and oxygen. As a result, these hexavalent COFs produce H₂O₂ spontaneously and efficiently from water and atmospheric air when exposed to visible light in both batch and flow reactors. Under laboratory conditions, the COFs demonstrate a quantum efficiency of 17.5 per cent under visible light at 420 nm in batch reactors. This system can be developed to construct self-cleaning surfaces and for disinfection treatments.

The research findings were published in the journal Nature Catalysis on 13 February 2024.

Prof Jiang said, “In this work, we successfully addressed a key and common issue in photocatalysts, electrocatalysts and heterogeneous catalysts, which is the efficient supply of charges and mass to catalytic sites. Our focus on precise structural design at the atomic level to explore both the skeletons and pores of COFs has led to the creation of an artificial photosynthesis system for H₂O₂ production, achieving unprecedented photocatalytic efficiency.”

“Combustion remains a source of air pollution across the world, both indoors and outdoors. We found that cooking on your gas stove produces large amounts of small nanoparticles that get into your respiratory system and deposit efficiently,” said Brandon Boor, an associate professor in Purdue’s Lyles School of Civil Engineering, who led this research.

Based on these findings, the researchers would encourage turning on a kitchen exhaust fan while cooking on a gas stove.

The study, published in the journal PNAS Nexus, focused on tiny airborne nanoparticles that are only 1-3 nanometers in diameter, which is just the right size for reaching certain parts of the respiratory system and spreading to other organs.

Recent studies have found that children who live in homes with gas stoves are more likely to develop asthma. But not much is known about how particles smaller than 3 nanometers, called nanocluster aerosol, grow and spread indoors because they’re very difficult to measure.

“These super tiny nanoparticles are so small that you’re not able to see them. They’re not like dust particles that you would see floating in the air,” Boor said. “After observing such high concentrations of nanocluster aerosol during gas cooking, we can’t ignore these nano-sized particles anymore.”

Using state-of-the-art air quality instrumentation provided by the German company GRIMM AEROSOL TECHNIK, a member of the DURAG GROUP, Purdue researchers were able to measure these tiny particles down to a single nanometer while cooking on a gas stove in a “tiny house” lab. They collaborated with Gerhard Steiner, a senior scientist and product manager for nano measurement at GRIMM AEROSOL.

Called the Purdue zero Energy Design Guidance for Engineers (zEDGE) lab, the tiny house has all the features of a typical home but is equipped with sensors for closely monitoring the impact of everyday activities on a home’s air quality. With this testing environment and the instrument from GRIMM AEROSOL, a high-resolution particle size magnifier — scanning mobility particle sizer (PSMPS), the team collected extensive data on indoor nanocluster aerosol particles during realistic cooking experiments.

This magnitude of high-quality data allowed the researchers to compare their findings with known outdoor air pollution levels, which are more regulated and understood than indoor air pollution. They found that as many as 10 quadrillion nanocluster aerosol particles could be emitted per kilogram of cooking fuel — matching or exceeding those produced from vehicles with internal combustion engines.

This would mean that adults and children could be breathing in 10-100 times more nanocluster aerosol from cooking on a gas stove indoors than they would from car exhaust while standing on a busy street.

“You would not use a diesel engine exhaust pipe as an air supply to your kitchen,” said Nusrat Jung, a Purdue assistant professor of civil engineering who designed the tiny house lab with her students and co-led this study.

Purdue civil engineering PhD student Satya Patra made these findings by looking at data collected in the tiny house lab and modeling the various ways that nanocluster aerosol could transform indoors and deposit into a person’s respiratory system.

The models showed that nanocluster aerosol particles are very persistent in their journey from the gas stove to the rest of the house. Trillions of these particles were emitted within just 20 minutes of boiling water or making grilled cheese sandwiches or buttermilk pancakes on a gas stove.

Even though many particles rapidly diffused to other surfaces, the models indicated that approximately 10 billion to 1 trillion particles could deposit into an adult’s head airways and tracheobronchial region of the lungs. These doses would be even higher for children — the smaller the human, the more concentrated the dose.

The nanocluster aerosol coming from the gas combustion also could easily mix with larger particles entering the air from butter, oil or whatever else is cooking on the gas stove, resulting in new particles with their own unique behaviors.

A gas stove’s exhaust fan would likely redirect these nanoparticles away from your respiratory system, but that remains to be tested.

“Since most people don’t turn on their exhaust fan while cooking, having kitchen hoods that activate automatically would be a logical solution,” Boor said. “Moving forward, we need to think about how to reduce our exposure to all types of indoor air pollutants. Based on our new data, we’d advise that nanocluster aerosol be considered as a distinct air pollutant category.”

This study was supported by a National Science Foundation CAREER award to Boor. Additional financial support was provided by the Alfred P. Sloan Foundation’s Chemistry of Indoor Environments program through an interdisciplinary collaboration with Philip Stevens, a professor in Indiana University’s Paul H. O’Neill School of Public and Environmental Affairs in Bloomington.

According to the Ancient Greek philosopher Pythagoras, ‘consonance’ — a pleasant-sounding combination of notes — is produced by special relationships between simple numbers such as 3 and 4. More recently, scholars have tried to find psychological explanations, but these ‘integer ratios’ are still credited with making a chord sound beautiful, and deviation from them is thought to make music ‘dissonant’, unpleasant sounding.

But researchers from Cambridge University, Princeton and the Max Planck Institute for Empirical Aesthetics, have now discovered two key ways in which Pythagoras was wrong.

Their study, published in Nature Communications, shows that in normal listening contexts, we do not actually prefer chords to be perfectly in these mathematical ratios.

“We prefer slight amounts of deviation. We like a little imperfection because this gives life to the sounds, and that is attractive to us,” said co-author, Dr Peter Harrison, from Cambridge University’s Faculty of Music and Director of its Centre for Music and Science.

The researchers also found that the role played by these mathematical relationships disappears when you consider certain musical instruments that are less familiar to Western musicians, audiences and scholars. These instruments tend to be bells, gongs, types of xylophones and other kinds of pitched percussion instruments. In particular, they studied the ‘bonang’, an instrument from the Javanese gamelan built from a collection of small gongs.

“When we use instruments like the bonang, Pythagoras’s special numbers go out the window and we encounter entirely new patterns of consonance and dissonance,” Dr Harrison said.

“The shape of some percussion instruments means that when you hit them, and they resonate, their frequency components don’t respect those traditional mathematical relationships. That’s when we find interesting things happening.”

“Western research has focused so much on familiar orchestral instruments, but other musical cultures use instruments that, because of their shape and physics, are what we would call ‘inharmonic’.

The researchers created an online laboratory in which over 4,000 people from the US and South Korea participated in 23 behavioural experiments. Participants were played chords and invited to give each a numeric pleasantness rating or to use a slider to adjust particular notes in a chord to make it sound more pleasant. The experiments produced over 235,000 human judgments.

The experiments explored musical chords from different perspectives. Some zoomed in on particular musical intervals and asked participants to judge whether they preferred them perfectly tuned, slightly sharp or slightly flat. The researchers were surprised to find a significant preference for slight imperfection, or ‘inharmonicity’. Other experiments explored harmony perception with Western and non-Western musical instruments, including the bonang.

Instinctive appreciation of new kinds of harmony

The researchers found that the bonang’s consonances mapped neatly onto the particular musical scale used in the Indonesian culture from which it comes. These consonances cannot be replicated on a Western piano, for instance, because they would fall between the cracks of the scale traditionally used.

“Our findings challenge the traditional idea that harmony can only be one way, that chords have to reflect these mathematical relationships. We show that there are many more kinds of harmony out there, and that there are good reasons why other cultures developed them,” Dr Harrison said.

Importantly, the study suggests that its participants — not trained musicians and unfamiliar with Javanese music — were able to appreciate the new consonances of the bonang’s tones instinctively.

“Music creation is all about exploring the creative possibilities of a given set of qualities, for example, finding out what kinds of melodies can you play on a flute, or what kinds of sounds can you make with your mouth,” Harrison said.

“Our findings suggest that if you use different instruments, you can unlock a whole new harmonic language that people intuitively appreciate, they don’t need to study it to appreciate it. A lot of experimental music in the last 100 years of Western classical music has been quite hard for listeners because it involves highly abstract structures that are hard to enjoy. In contrast, psychological findings like ours can help stimulate new music that listeners intuitively enjoy.”

Exciting opportunities for musicians and producers

Dr Harrison hopes that the research will encourage musicians to try out unfamiliar instruments and see if they offer new harmonies and open up new creative possibilities.

“Quite a lot of pop music now tries to marry Western harmony with local melodies from the Middle East, India, and other parts of the world. That can be more or less successful, but one problem is that notes can sound dissonant if you play them with Western instruments.

“Musicians and producers might be able to make that marriage work better if they took account of our findings and considered changing the ‘timbre’, the tone quality, by using specially chosen real or synthesised instruments. Then they really might get the best of both worlds: harmony and local scale systems.”

Harrison and his collaborators are exploring different kinds of instruments and follow-up studies to test a broader range of cultures. In particular, they would like to gain insights from musicians who use ‘inharmonic’ instruments to understand whether they have internalised different concepts of harmony to the Western participants in this study.