The mercury is soaring across India, with many places reporting unusually high temperature readings. It may not be possible to link each heat event to climate change, but we know climate change is bringing such anomalies to more areas, and with greater intensity.

We also know climate change is disproportionately affecting society’s most vulnerable members, including those with physical ailments, the elderly, the poor, and the socially and economically marginalised. And we also know climate change has become the basis of a slew of psychological afflictions of its own, including eco-anxiety, eco-paralysis, and solastalgia (a form of emotional or existential distress rendered by environmental changes), together with seeding general concerns in communities worldwide about their livelihoods, future, the future of their children, and their culture.

But let’s not forget that climate change’s multi-dimensional assault on reality as we know it also potentially includes being able to worsen existing mental health conditions.

A dubious distinction

A study published in 2023 in the journal GeoHealth reported that an extreme heat event in the Canadian province of British Columbia in 2021 affected people with schizophrenia more than those with kidney and heart disease. The study’s authors, of the British Columbia Centres for Disease Control and Health Canada, also wrote that people with mental health conditions seem to be at a greater risk of succumbing to heat-related deaths. The stakes were found to be even higher for people diagnosed with schizophrenia, anxiety or bipolar disorder.

During the eight-day extreme heat event in 2021, the province of British Columbia experienced temperatures as high as 40 degrees C when the average temperatures have been around 20 degrees C. The region recorded around 740 excess deaths during this heat wave.

To understand who was affected the most during this event, the researchers compared 1,614 deaths recorded over a month in 2021 with 6,524 deaths recorded in the same time period nine years ago. They analysed the data based on 26 medical conditions, including heart disease, schizophrenia, chronic kidney disease, dementia, depression, Parkinson’s disease, and osteoporosis.

The scientists wrote that they expected to find people with kidney and heart diseases to be most at risk, but were surprised to find that that dubious distinction belonged to people with schizophrenia. In particularly, they reported that 8% of the people surveyed in 2021 were previously diagnosed with schizophrenia as opposed to 2.7% of the people surveyed nine years ago. This was a 200% increase from a summer in which heat waves weren’t recorded.

To be sure, while people with schizophrenia were found to be at greater risk of heat-related distress than those with kidney and heart diseases, the latter weren’t immune: they were at risk as well, just less so.

Dysfunction of the hypothalamus

A closer look at the data revealed that of the 280 people whose deaths were confirmed to be related to heat, 37 people had schizophrenia. “These results show that people with schizophrenia need extra protection, extra support and extra care,” Sarah Henderson, one of the epidemiologists who led the study and the scientific director of Environmental Health Services at the British Columbia Centre for Disease Control, told Science.

The researchers believe one of the main reasons people with schizophrenia were more vulnerable to heat stress could be as a result of the dysfunction of the hypothalamus, a structure embedded deep in the human brain. Its main function is to maintain the homeostasis of the body, i.e. to keep the body in a stable condition that ensures it can carry out its normal function. This means it controls of the body’s temperature, heart rate, hunger, thirst, mood, libido, sleep, and the regulation of hormones.

Certain antipsychotic medications prescribed to people with schizophrenia have also been found to interfere with the hypothalamus’s workings. One side-effects of such drugs has been a tendency to raise the body’s temperature, which when coupled with anomalously high ambient temperatures can rapidly prove fatal.

People with schizophrenia also often have psychotic symptoms such as hallucinations, delusions, disorganised thinking, and memory loss. They may also suffer from anosognosia: a condition in which they’re unable to sense that they’re ill. All this together with comorbidities like diabetes and hypertension can make life very difficult for people with schizophrenia, including potentially interfere with their ability to seek help.

As it happens, marginalisation, lower economic status, and a propensity for loneliness are risk factors for people with schizophrenia, and the same factors can heighten an individual’s vulnerability to heat-related illnesses, as the infamous 1995 Chicago heat event demonstrated.

Yet another tentacle

But for some antipsychotic medicines’ potential to interfere with people’s experience of anomalous ambient heat, scientists have cautioned that they shouldn’t be discontinued or tampered with because these are ‘lifesaving therapies’. They have suggested that the risk factors associated with schizophrenia, including social isolation, should be tackled instead with interventions like counselling and checking in on them regularly.

In a statement issued by the British Columbia Centres for Disease Control, Faydra Aldridge, CEO of the British Columbia Schizophrenia Society, said, “As demonstrated by the recent research, because individuals living with schizophrenia are more susceptible to heat-related illness, it is essential that families and caregivers are aware of the increased risk, identify potential risk factors and take prompt action to help their loved one during a heat wave.”

She added that “educating ourselves to recognise symptoms of heat-related illness and take emergency cooling measures will help ensure everyone’s safety during heat waves.”

One of the defining characteristics of climate change is the nonlinear nature of its effects, i.e. their ability to compound rapidly, affecting several walks of human life both directly and indirectly. The GeoHealth study elucidated one more example of this ability, adding to previous work that has examined its influence on everything from domestic violence to child-trafficking.

Heatstroke is an important condition to know about that can happen when your body overheats and can’t cool down.

What is heatstroke

Heatstroke occurs when the body overheats to an extreme level, leading to a malfunction in its cooling system. Unlike heat exhaustion, which is less severe and typically involves heavy sweating and feeling faint, heatstroke is a critical condition where the body’s temperature regulation fails entirely. In essence, it’s like your body’s internal thermostat going haywire, potentially causing damage to vital organs and even proving fatal if not treated promptly.

Symptoms

To recognise heat stroke before it escalates, keep an eye out for key warning signs. Kids should be aware of symptoms such as hot, dry skin, confusion, rapid heartbeat, dizziness, and nausea. These symptoms occur when the body’s internal temperature regulation system becomes overwhelmed by the heat. When the body can’t cool down efficiently through sweating, it leads to dehydration and a rise in core body temperature. This, in turn, triggers a cascade of physiological responses, including confusion and an elevated heart rate, as the body struggles to cope with the heat stress.

Keeping yourself hydrated, wearing lighter clothes and using sunscreen is the most common action to beat the heat.

The sun is strongest between 10 am and 4 pm, so plan outdoor activities for the cooler parts of the day, like early mornings or evenings.

Expert advice

We spoke to Prof. Dr. P. Saravanakumar, MD, DNB Pediatrics, PhD, who has been an expert in the field for 17 years. Dr. Saravanakumar’s insights into heatstroke prevention and management are invaluable, particularly during the hot summer months when children are most vulnerable.

While children love playing outside during vacations, they can easily forget to stay hydrated in the heat. This can lead to dehydration, which is the loss of water in the body. Dr. Saravanakumar warns that dehydration can cause:

• Excessive thirst and dry mouth
• Headache and nausea
• Muscle cramps and rashes
• Difficulty breathing (in some cases)

Cold treats and summer changes can worsen dehydration

Dr. Saravanakumar highlights that while children may crave cold drinks and ice cream to quench their thirst, these sugary treats don’t effectively rehydrate them. He emphasises that these choices, along with changes in summer eating habits (like consuming more outside food), can lead to:

Upper respiratory infections: Cold drinks can irritate the throat, potentially increasing susceptibility to coughs, colds, and even tonsillitis.

Stomach problems: Unfamiliar outside food or excessive watermelon consumption in some children can cause stomach aches and diarrhoea, further contributing to dehydration.

Why children are more susceptible to heatstroke

“Body wise, children have more surface area to their body mass than adults. So because the surface area is very high and their skin texture is also softer and thinner, these make the children have a higher risk of exhaustion, sweating, excess evaporation, when compared to adults.”

Higher surface area to body mass ratio

Compared to adults, children have more skin exposed relative to their body size. This larger surface area allows them to heat up faster and lose heat slower.

Research indicates that children sweat less overall than adults, limiting their ability to cool down through sweating, which puts them at a greater risk of overheating. Additionally, their developing bodies have a less efficient system for dissipating heat compared to adults. These factors combine to make children more susceptible to heat-related illnesses, underscoring the importance of proactive measures to prevent heatstroke and ensure their well-being during hot weather.

Taking action

Dr. Saravanakumar outlines the crucial steps to take if you suspect heatstroke in a child:

• Cool the child down: Move them to a shaded or air-conditioned area. Offer cool fluids (not too cold) to drink.
• Evaporative cooling: You can use the evaporation method to further lower their body temperature. This involves using cool, damp cloths or towels on the child’s skin while gently fanning them. Ice packs on the groin, neck, and armpits can also be helpful.
• Seek medical attention: Immediately take the child to a doctor or emergency room.

Stay alert: Monitor the child’s alertness and continue offering fluids orally if they are awake and responsive.

Hydration is key

While there’s no one-size-fits-all water intake recommendation, here’s a general guideline:

Children under 5 years: Aim for 820 ml to 1 litre of fluids per day.

Children up to 13 years: Around 3 litres of fluids per day.

It’s important to offer fluids throughout the day, not just when a child feels thirsty. Water is ideal, but juices and milk can also contribute to hydration. Remember, electrolyte balance is important, so consider incorporating options with some sodium content.

“One interesting pattern observed for the past few years is that earlier heat stroke cases would come only during summer seasons but now it may come any time of the year. This might be an effect of climate change as well. There have been more recent cases of heat exhaustion,” said Dr Saravanakumar

A scientist looks at hypometabolic and hypoperfusion patterns at the single-subject level from a patient suffering from Alzheimer’s disease at the Memory Centre at the Department of Readaptation and Geriatrics of the University Hospital (HUG), in Geneva, Switzerland, June 6, 2023.
| Photo Credit: Reuters

People who carry two copies of the APOE4 gene are virtually guaranteed to develop Alzheimer’s and face symptoms at an earlier age, researchers reported on Monday in a study that could redefine such carriers as having a new genetic form of the mind-wasting disease.

The reclassification could change Alzheimer’s research, diagnosis and approaches to treatment, according to the researchers, whose study was published in the journal Nature Medicine.

“Through these data we are saying that perhaps this is a genetic form of this disease, not merely a risk factor indication,” study co-author Sterling Johnson of the University of Wisconsin’s Alzheimer’s Disease Research Center told reporters in a briefing.

Scientists have known for three decades that people with two copies of APOE4 gene variant have significantly higher risk of developing the disease than people with the most common version of the APOE gene, known as APOE3. About 2% to 3% of the general population, or 15% of people with Alzheimer’s, have two copies of the APOE4 variant.

ō”This study adds compelling data to suggest that people with two copies of this gene are almost guaranteed to develop Alzheimer’s if they live long enough, and that they will develop Alzheimer’s earlier than people without this gene,” said professor Tara Spires-Jones, an Alzheimer’s researcher at the University of Edinburgh who was not involved in the study.

Dr. Juan Fortea of the University of Barcelona and colleagues studied more than 3,000 donated brains from the U.S. National Alzheimer’s Coordinating Center, as well as biological and clinical data on more than 10,000 individuals from three countries.

They found that by age 65, at least 95% of people with two copies of APOE4 – known as homozygotes – had abnormal levels of an Alzheimer’s-related protein called beta amyloid in their spinal fluid, and 75% had positive brain scans for amyloid.

Nearly all APOE4 homozygotes in the study had higher levels of amyloid at age 65 than people who did not carry the risk variant.

The findings suggest APOE4 homozygotes meet the three main criteria for being a genetic disease: nearly everyone with these two variants have Alzheimer’s biology; they develop symptoms at about the same rate; and clinical and biological changes occur in a predictable sequence, the researchers said.

Professor David Curtis of the UCL Genetics Institute, who was not involved in the research, remained unconvinced. “I do not see anything in this paper to justify the claim that carrying two copies of APOE4 represents some ‘distinct genetic form’ of Alzheimer’s disease’,” he said in a statement.

“No matter how many (copies) of APOE4 one carries the underlying disease processes seem similar across cases of Alzheimer’s disease,” he said.

Treatment implications

The findings could have implications for the recently approved Alzheimer’s treatment Leqembi from Eisai and Biogen, a drug that removes amyloid from the brain.

In clinical trials, patients with two copies of the APOE4 variant have much higher rates of brain bleeding and swelling associated with the treatment. Because of this, some centers do not treat these patients, Dr. Reisa Sperling, an Alzheimer’s researcher at Mass General Brigham who worked on the study, said in a briefing with reporters.

The findings suggest they should be treated at a younger age because “we know they’re very, very likely to progress to impairment quickly,” she said.

Dr. Samuel Gandy, an Alzheimer’s researcher at Mount Sinai in New York, said the findings stress the need to enroll APOE4 homozygotes into trials designed to prevent the disease before they develop symptoms. Sperling is conducting one such trial.

Heather Snyder of the Alzheimer’s Association said the findings, if correct, could have significant implications for how disease risk is assessed, how it is studied in clinical trials and how treatments are developed.

The new designation would be for Alzheimer’s that develops later in life. Other genetic forms include Autosomal-dominant Alzheimer’s Disease, which is caused by mutations in three different genes, and Down syndrome.

A key limitation of the study is that it involved mostly people of European ancestry. The team said more study is needed in people of African descent, a population in which APOE4 appears to convey a lower risk of Alzheimer’s disease.

The story so far: In September 2025, NASA’s four-member Artemis crew is scheduled fly around the moon in preparation for the space agency’s mission to land on the moon again. To boost such scientific missions, the White House Office of Science and Technology Policy (OSTP) on April 2, directed its space agency, the National Aeronautics and Space Administration (NASA), to establish a Coordinated Lunar Time (LTC) to standardise cislunar operations with the universal time followed on Earth.

Explaining the move, OSTP Deputy Director for National Security Steve Welby said, “A consistent definition of time among operators in space is critical to successful space situational awareness capabilities, navigation, and communications.”

Speaking about the difference between the passage of time on the moon and Earth, he said, “Time appears to pass more slowly where gravity is stronger, like near celestial bodies. As a result, the length of a second on Earth is different to an observer under different gravitational conditions, such as on the moon.”

The LTC will be the standard to measure cislunar operations — space activities between the moon and Earth — with Coordinated Universal Time (UTC), the global time used to regulate time on Earth. Roping in federal departments like the U.S. Departments of Commerce, Defense, State, and Transportation, the White House has set a deadline of December 31, 2026, for NASA and its international partners to deliver a strategy to implement LTC.

The project falls under the current administration’s National Cislunar Science and Technology Strategy. NASA has been directed to engage with the 39 nations who have signed the Artemis Accords for this project. It is expected to present its consideration of the LTC by December 31, 2024 as part of its Moon-to-Mars Architecture Concept Review cycle.

What is Coordinated Lunar Time (LTC)?

In 2023, the European Space Agency (ESA) launched a project called ‘Moonlight’ to design satellites for astronauts and robotic explorers, which will be used to support NASA’s moon mission ‘Artemis.’ While working on the project, questions arose on setting a single time zone for the moon and how to go about it.

Speaking to the publication Wired, ESA engineer Javier Ventura-Traveset said, “On Earth, we use a 24-hour day based on the planet’s rotation. However, the moon rotates much more slowly – every 29.5 Earth days.” Due to its slow rotation, it would be practical to have less than Earth’s 24 time zones — ideally, a single time zone for the moon would be natural, said Mr. Ventura-Traveset, highlighting that this would be similar to the Coordinated Universal Time (UTC).

The idea for the UTC was formulated in the 1960s. Atomic clocks — devices that measure time based on the vibration of atoms — are known for their extreme accuracy in measuring time. Meanwhile, solar time, calculating by measuring the rotation of Earth on its axis relative to the Sun, is variable in nature. A weighted average of hundreds of atomic clocks produces the International Atomic Time (TAI).

The UTC was designed as a way to accommodate the difference between solar time and atomic time, and is kept within 0.9 seconds of solar time to follow Earth’s rotation variations and within an exact number of seconds of the TAI. Currently, moon missions follow the time of the country which operates the spacecraft, while the International Space station (ISS) runs on the UTC. However, a standardised time for space and the moon is not followed.

“We would reproduce something like Coordinated Universal Time so astronauts could follow a 24-hour cycle as they do on the International Space Station,” Mr. Ventura-Traveset told Wired. However, he added that it will be out of sync with the moon’s light and dark periods (due to its slow rotation, the moon faces away or towards the Sun for long periods of time), and that it wouldn’t be sensible to have a weeks-long “day” followed by a weeks-long “night.” 

The White House’s Celestial Time Standardization policy seeks to assign a time standard to each celestial body and its surrounding space environment, first focusing on the lunar surface and missions operating in cislunar space. It outlines the four features such a time standard must possess:

1. Traceability to UTC: Lunar Time is analogous to Terrestrial Time on Earth (TAI+ 32.184 seconds). Similar to Terrestrial Time, Lunar Time may be set through an ensemble of clocks on the moon. This time standard, i.e., LTC may directly employ or distribute the UTC offsets required to maintain both local time and UTC time within tolerance limits.
2. Scalability beyond the Earth-Moon system: Conversion of LTC to UTC for operations involving interactions with Earth will be possible by using the above approach to set the LTC. This approach is also extensible to space environments beyond the Earth-Moon system (for example, for Mars).
3. Accuracy for precision navigation and science: The LTC will give users in cislunar space a reference time standard near the gravitational environment in which they operate. Space assets can synchronise with each other with precision for navigation.
4. Resilience to loss of contact with Earth: The reference time – LTC – must survive independently when contact to Earth is lost.

Unlike Earth, the moon will have only one time zone and daylight saving will be unnecessary, the Smithsonian magazine estimates.

Why is LTC needed?

Previous moon missions involved astronauts visiting the lunar surface, completing their work and flying home. However, with space agencies across the world aiming to establish a permanent human presence on the moon, LTC is required, Mr. Ventura-Traveset said. “Up to now, when you have a mission on the moon, you would always synchronise with a time zone on Earth. But now we will have many missions in the future, and having a common reference time is really needed,” he said.

According The Scientific American, the pressing need for LTC is due to the plan to create a dedicated global satellite navigation system (GNSS) for the moon by 2030. This system will function similar to how the Global positioning system (GPS) and other navigation networks work on Earth.

Moon missions of various agencies will need an official lunar time to communicate with Earth-based stations and each other. “All this has to trace to one kind of a time reference, otherwise you have chaos and things do not work together,” ESA engineer Jörg Hahn said to The Scientific American.

Commercial operations on lunar surface involving transactions and logistics will be more reliable with the LTC, the OSTP says.

Issues in defining and implementing LTC

The process of defining lunar time is complicated by the effect of the moon’s gravitational pull. As per special relativity theory, due to the weaker gravitational pull of the moon, a clock on the moon would run faster than one on Earth, explains Patrizia Tavella, Head of Time department at the International Bureau of Weights and Measures in Sèvres, France, in an interview with The Scientific American. “A clock’s speed would also change depending on its position on the lunar surface, because of the moon’s rotation,” she adds.

NASA aerospace engineer Cheryl Gramling estimates that any clock on the moon would gain 56 microseconds over 24 hours. Per an estimate by The Scientific American, at least three master clocks which tick at the moon’s natural pace must be installed. The output of these three clocks coupled with an algorithm is expected to generate a more accurate time standard.

“Most importantly, lunar time will have to be practical for astronauts there (ISS),” ESA’s strategic planning head Bernhard Hufenbach said to the Smithsonian magazine. Each lunar day lasts as long as 29.5 Earth days. With the Artemis Programme aiming for a lunar landing as early as 2026, it needs to consider how to adapt to this challenge for a long-duration stay.

“But having established a working time system for the moon, we can go on to do the same for other planetary destinations,” said Mr. Hufenbach, alluding to setting time standards for other nearby celestial bodies like Mars.

In November 2022, the need for a unified lunar time was voiced globally by space agencies and academic organizations at an ESA meeting in Noordwijk, the Netherlands. Most participants agreed on “a common lunar reference time,” but debated if a single organisation should set and maintain time on the moon.

Apart from the US, several countries have lunar ambitions. China has stated that it will put its astronauts on the moon by 2030, while India plans to land in 2040. In January, Japan became the fifth country to land a spacecraft on the moon, after US, Russia, India and China. However, India is the only one to land a spacecraft near the lunar south pole.

“U.S. leadership in defining a suitable standard will benefit all spacefaring nations,” the OSTP stated. Getting consensus on LCT should be easier for the U.S due to the involvement of the Artemis Accord nations. However, two of its biggest space rivals – China and Russia – have not signed the accords, posing hurdles.

Representative Fna C1 and Fna C2 strains co-cultured with human colon cancer cells. The grid shows the results of computational analysis of confocal imaging. Independent masks for cancer epithelial cells (grey), and intracellular bacterial cells (Fna C1 green, Fna C2 lavender) were generated. The masks were used to calculate the percent of cancer cells with intracellular Fna. The scale bar is 20 μm.
| Photo Credit: Zepeda-Rivera, M., Minot, S.S., Bouzek, H. et al. A distinct Fusobacterium nucleatum clade dominates the colorectal cancer niche. Nature 628, 424–432 (2024).

The bacteria known as Fusobacterium nucleatum live in the human mouth and are rarely found elsewhere. But in cases of cancer of the colon or the rectum, the bacteria are found in tumours in the gut, where they help cancer cells escape from the immune system and spread to other parts of the body.

In a new study, a group of researchers from the Fred Hutchinson Cancer Center in the U.S. has identified a distinct subtype of the bacterium that’s found in relatively greater quantities in colorectal cancer (CRC) tumours.

CRC is the seventh most common type of cancer in India, where the number of cases rose by 20% from 2004 to 2014. Worldwide, the overall CRC incidence has declined but, experts wrote in the journal Science last year, the incidence of age-adjusted early-onset CRC “has risen at an alarming rate of 2-4% in many countries, with even sharper increases in individuals younger than 30 years.”

According to the team’s experiments, described in a paper in Naturein March, some genetic factors could be boosting Fusobacterium’s ability to associate with cancers of the gut. The team also showed that when mice were infected with this type of Fusobacterium, their intestines developed precancerous formations called adenomas.

Experts said the study’s findings could be used in future to develop tests to detect CRC early and develop targeted treatment options.

A clade of its own

The researchers began by culturing Fusobacterium bacteria collected from 130 human CRC tumours in the laboratory. Then they mapped the entire genetic composition of the isolated bacteria and found that out of the four known Fusobacterium nucleatum subspecies, only Fusobacterium nucleatum animalis (Fna) was significantly associated with CRC tumours.

Individual members of the same species have slightly different DNA. Pangenomic analysis helps researchers map all the genes in a species as well as those parts of the genome that some but not all members of the species have. This part is called the accessory genome. The members of a species can be further subclassified depending on the accessory genomes they have.

In their analysis, the researchers found Fna has the smallest core genome (the part that all members of the species have), indicating there could be different subtypes of Fna. In response, they traced the evolutionary history of the bacteria by tracing the changes in its genes. This analysis revealed that Fna, instead of being one homogenous group, is composed of bacteria from two different evolutionary lineages.

Scientists call a group of life-forms belonging to one evolutionary lineage a clade. Thus, the researchers had identified two different clades of Fna: they called these Fna C1 and Fna C2. They further found Fna C2 bacteria are significantly associated with CRC tumours and that they have extra genetic factors to help them in this regard.

Colonising the gut

Both physical and genetic differences between the two clades seemed to contribute to Fna C2 bacteria’s ability to associate with CRC tumours. Physically, the Fna C2 bacteria looked longer and thinner than Fna C1 bacteria. Such differences can affect how bacteria are able to live in host tissue as well as evade the body’s immune system, the authors wrote in their paper.

Genetically, Fna C2 bacteria had genes required to munch two compounds for energy in the human gut: ethanolamine and 1,2-propanediol. These genes were missing in Fna C1. So the researchers concluded Fna C2 bacteria’s ability to associate with CRC tumours was at least partly contingent on them “having increased nutrient scavenging mechanisms and enhanced metabolic potential”.

The researchers validated their findings by analysing genomes present in more than 1,200 human stool samples, roughly half of which were from people with CRC while others were from healthy individuals. They found that the Fna genes required to metabolise ethanolamine and 1,2-propanediol were more enriched in stool samples from CRC patients than in samples from people without CRC.

Mouth to gut

Scientists previously believed Fusobacterium bacteria could go from the mouth to the gut by infecting the bloodstream when, say, someone brushed their gums too hard or during routine dental procedures. The authors of the new Nature paper pitched a new route: that the bacteria could have descended through the gastrointestinal tract to reach the colon.

Bacteria don’t usually take this path because they can’t survive the highly acidic environment of the stomach.

But the researchers found Fna C2 could. These bacteria could grow in more acidic conditions than could Fna C1 bacteria — and they also had specific genes that could resist the effects of acids. These genes came online when the acidity was comparable to that of stomach acid.

In mice as in humans

Next, the researchers investigated whether Fna C2 could induce the development of tumours in the gut. For this, they introduced Fna C1 bacteria in the inflamed guts of some mice and Fna C2 bacteria in the inflamed guts of others. (These mice are a common animal model used to investigate conditions that also affect humans.) They found a significantly higher incidence of adenomas in the intestines the mice treated with Fna C2 bacteria.

They also noted that the intestines of Fna C2-treated mice had different metabolic profiles — changes consistent with previously reported associations between differential metabolite levels and tumour progression.

“Overall, our results demonstrate the ability of Fna C2, but not Fna C1, to metabolically affect the intestinal milieu towards” conditions conducive to CRC, the authors wrote.

Finally, the researchers tested their hypotheses in a cohort of human patients. Working with CRC tissue and non-cancerous tissues from the same individual, the authors confirmed that Fna C2 was the only Fusobacterium subtype enriched in CRC tissues. They found similar results in stool samples from those with CRC but not in those from healthy individuals.

Long road to clinical trials

According to Neetu Kalra, a cancer therapeutics researcher at Azim Premji University, Bhopal, “The study presents promising prospects for the advancements of microbial cellular therapies, which involve the use of modified bacterial strains to directly administer treatments into tumours.”

Varun Aggarwala is an assistant professor at Jio Institute, Mumbai, who also works on faecal transplants for infectious and inflammatory bowel diseases. He called the study “comprehensive” and said “studies like this provide a solid foundation for the broader community to design targeted microbial interventions and diagnostics for CRC.”

He added that future research should track the gut and oral microbiome of high-risk individuals and their tumour microbiome after a CRC diagnosis to understand how certain strains of bacteria can cause cancer.

Similarly, Dr. Kalra said studies to come could look at the “colonisation timeline” of Fna C2 bacteria: the CRC stage at which the bacteria become associated with the tumours. “If colonisation occurs early,” she explained, “it could facilitate early CRC diagnosis”.

On the flip side, she also said developing a drug that could selectively target Fna C2 bacteria without affecting Fna C1 or other gut bacteria “presents a significant challenge”.

Sayantan Datta is a science journalist and a faculty member at Krea University. They tweet at @queersprings.

The story so far: For those trying to look inside the human body without surgery, magnetic resonance imaging is an indispensable tool. The underlying techniques were worked out in the early 1970s; later the same decade, Paul Lauterbur and Peter Mansfield refined them to pave the way for their commercial use. For these efforts, they were awarded the medicine Nobel Prize in 2003, speaking to the significance of the technique and its place in modern medical diagnostics.

What is magnetic resonance imaging?

Magnetic resonance imaging (MRI) is used to obtain images of soft tissues within the body. Soft tissue is any tissue that hasn’t become harder through calcification. It is a non-invasive diagnostic procedure widely used to image the brain, the cardiovascular system, the spinal cord and joints, various muscles, the liver, arteries, etc.

Its use is particularly important in the observation and treatment of certain cancers, including prostate and rectal cancer, and to track neurological conditions including Alzheimer’s, dementia, epilepsy, and stroke. Researchers have also used MRI scans of changes in blood flow to infer the way the activity of neurons is changing in the brain; in this form, the technique is called functional MRI.

Because of the MRI technique’s use of strong magnetic fields, individuals with embedded metallic objects (like shrapnel) and metallic implants, including pacemakers, may not be able to undergo MRI scans. In fact, if they have a credit card in their pocket, the magnetic fields will wipe its magnetic strip!

How does MRI work?

An MRI procedure reveals an image of a body part using the hydrogen atoms in that part. A hydrogen atom is simply one proton with one electron around it. These atoms are all spinning, with axes pointing in random directions.  Hydrogen atoms are abundant in fat and water, which are present almost throughout the body.

An MRI machine has four essential components. The machine itself looks like a giant donut. The hole in the centre, called the bore, is where the person whose body is to be scanned is inserted. Inside the donut is a powerful superconducting magnet whose job is to produce a powerful and stable magnetic field around the body. Once the body part to be scanned is at the centre of the bore, the magnetic field is switched on.

Each hydrogen atom has a powerful magnetic moment, which means in the presence of a magnetic field, the atom’s spin axis will point along the field’s direction. The superconducting magnet applies a magnetic field down the centre of the machine, such that the axes of roughly half of the hydrogen atoms in the part to be scanned are pointing one way and the other half are pointing the other way. This matching is almost exact: in around a million atoms, only a handful remain unmatched — i.e. a small population of ‘excess’ atoms pointing one way or the other.

The machine’s third component is a device that emits a radiofrequency pulse at the part under the scanner. When the pulse is ‘on’, only the small population of ‘excess’ atoms absorbs the radiation and gets excited. When the pulse goes ‘off’, these atoms emit the absorbed energy and return to their original, lower energy states. The frequency of pulse the ‘excess’ atoms have to absorb is called the Larmor frequency. Its value depends on the strength of the magnetic field and the type of tissue in which the atoms are present.

The fourth and final component, a detector, receives the emissions and converts them to signals, which are sent to a computer that uses them to recreate two- or three-dimensional images of that part of the body.

What are the pros of MRI?

After the big, powerful magnetic field comes on, the MRI machine activates three magnets that produce smaller magnetic fields that are weaker than the main field by about 80-times, if not more. These fields also have a gradient, i.e. they’re not uniform. These fields interfere with the main field at the part to be scanned such that the resulting field highlights very specific portions, which can be the focus of the scan.

By turning the gradient magnets on and off in specific sequences, the MRI machine can thus scan portions that are just a few millimetres wide. The sequences can also be organised such that the machine scans different parts of the individual’s body without asking them to move inside the bore.

In fact, because of the way the machine is built and the magnets are organised inside it, an MRI scan can practically image the body from all useful directions and, if required, in very small increments.

When the ‘excess’ atoms emit the energy they’d absorbed to return to their lower energy states, the return happens over a duration called the T1 relaxation time. The hydrogen atoms in water have different values of T1 depending on the tissue in which they’re present. An MRI machine exploits this fact to show different tissues in different shades of grey. Clinicians may also inject an individual with a contrast agent — typically a gadolinium-based compound — that lowers the T1 time in some tissues, improving their visibility in an MRI scan.

Finally, researchers have deeply investigated the effects of strong magnetic fields on the body. MRI scans don’t pose any threats; once the magnetic fields are taken away, the atoms in the scanned part don’t remain affected. There is no long-term harm associated with scans. However, a scan’s effects on pregnant women aren’t as well-studied, so many scanning facilities simply refuse such appointments.

What are the cons of MRI?

MRI machines are expensive: depending on the specifications, including the strength of the magnetic fields and the imaging quality, they cost from a few tens of lakh rupees to a few crores. Diagnostic facilities pass this cost on to its patients. Based on the clinical requirements, scans often cost Rs 10,000 or more each — a sizeable sum in India, especially for those without insurance, and more so for those required to get multiple MRI scans.

These costs are compounded by the discomfort of using the machine. While it’s an advantage that an individual inside the bore doesn’t have to move for the machine to scan different parts, the individual is actually expected to lie still for tens of minutes, until the scan is complete. If the individual moves, the resulting image will be distorted and the scan will have to be repeated. The problem is exacerbated if the individual is claustrophobic (although some ‘open-bore’ MRI machine designs can alleviate this issue).

Generating a magnetic field of strength 1 tesla or more — as the main magnet does — is no mean feat. To do so, a heavy current is passed through coils of wire made of a superconducting material. When the setup is cooled with liquid helium, the wires become superconducting and the current passing through them plus the geometry of the wires produces a strong magnetic field. While the wires don’t lose any energy as heat — which a non-superconducting material would — maintaining the setup is energy-intensive, which is expensive.

Further, the switching of such heavy currents within the machine, as the gradient coils are operated in sequence, means the machine produces loud noises when operating. This can be an additional source of discomfort for the individual.

Salil Gupte, President, Boeing India and South Asia, with Meghraj M., Sathvik Poojary and Sanjana S. who won the Boeing National Aeromodelling Competition 2024. The team is from Nitte Mahalinga Adyanthaya Memorial (NMAM) Institute of Technology, Karkala in Udupi district of Karnataka.
| Photo Credit: Special Arrangement

A team from Nitte Mahalinga Adyanthaya Memorial (NMAM) Institute of Technology, Karkala in Udupi district of Karnataka, won the ninth annual Boeing National Aeromodelling Competition, which attracted more than 2,350 students from 855 institutions in India.

This year, the competition saw an increase in female participation, with 28% of women participating in the final rounds.

Forty-four finalists from 13 teams made it to the finale that was held in Bengaluru. The team comprising Meghraj M., Sathvik Poojary and Sanjana S. from NMAM Institute of Technology were declared winners of the competition.

The zonal rounds of the competition were held in IIT Kanpur, IIT Bombay, IIT Kharagpur, and IIT Madras. The top 13 teams travelled to Bengaluru for the final round, which was hosted by R.V. College of Engineering.

In addition, 60 students from Shishu Mandir and Building Blocks schools were invited for a learning session on the sidelines of the competition to help encourage and promote awareness, knowledge, and exposure to aviation and aeromodelling.

The Boeing National Aeromodelling Competition for students across India is sponsored by aircraft manufacturer Boeing, and organised in association with IIT Bombay, IIT Kanpur, IIT Kharagpur, IIT Madras, and R.V. College of Engineering.

The competition started as an annual event in 2013 to provide a nationwide platform for students who have a keen interest in aerospace engineering and related fields. The competition allows them to demonstrate their skills and creativity in designing, building, and flying fixed-wing aircraft models of different types and sizes.

Salil Gupte, President, Boeing India and South Asia, said, “Over its nine editions, the Boeing National Aeromodelling Competition has become an inspirational platform that complements the aspirations of India’s young aviation enthusiasts. I congratulate the participants and winners for their disruptive ideas that show that the possibilities are limitless in aviation, and I thank our partners for helping build an ecosystem of learning and innovation in aviation.”

“All animals are equal, but some are more equal than others” — this line from George Orwell’s 1945 classic ‘Animal Farm’ perfectly describes how bias operates in human societies.

In a study published in May last year, psychologists explored how people subconsciously evaluate different racial groups. They screened responses from more than 60,000 participants belonging to four groups: ‘white’, ‘blacks’, ‘Hispanics’, and ‘Asians’ (67% of them lived in the U.S.)

Using a psychological test called an implicit association test (IAT), scientists found stark differences in participants’ explicit statements from their implicit beliefs. While everyone verbally said they believed in the equality of all races, they also harboured implicit biases in favour of socially advantaged groups. This bias was also universal, irrespective of the racial identity of the participants.

The IAT is built on the premise that if two things — words, concepts, events, etc. — have co-occurred in our experience over and over again, we put those two things together very quickly. The test includes a series of quick-fire rounds to sort words related to concepts (e.g. “thin”, “fat”, “white”, “black”, etc.) and assessments (“good” or “bad”) into categories. A participant’s score is based on the time taken to sort words when concepts and assessments are combined. For example, if test subjects combine “white” with “good” faster than they do “white” with “bad”, the test suggests they have an implicit bias favouring white people.

The brain’s shifting criteria

That all humans are equal is a scientific fact established by modern genetics. However, the history of humankind is replete with people from one cultural or social group treating those from others as if they are less than human — a phenomenon called pseudo-speciation. The basis of this deep-seated tendency in people continues to be the focus of intense research efforts in psychology and neuroscience.

Many recent studies have found that our brains process information about in-groups (i.e. “us”) and out-groups (“them”) differently. In particular, a study published on March 18, 2024, in Frontiers in Psychology reported that, bizarrely, the criteria our brains use to categorise others as “us” or “them” shift constantly. Researchers asked half of a group of young, white participants to describe how they — as white people — differed from black individuals. They asked the other half to describe how they differed from old persons. In this way, the researchers drew the participants’ attention to specific aspects of their own social identity (“white” or “young”) and to perceived differences from the respective outgroups.

Assessing the participant responses with IAT, the researchers found that directing participants’ attention to different facets of their in-group identity was sufficient to change their intergroup bias. That is, the participants’ preferences changed depending on whether their brains used age or race to classify others.

Bias is learned

Neuroimaging studies have corroborated such findings from psychology research, and have clarified that information-processing in the brain is different depending on whether it pertains to “us” or to “them”.

Brain regions that activate in response to the direct experience of pain as well as empathy for the pain of others include parts of the anterior cingulate cortex and insula. The first report showing this selective processing was published more than a decade ago. Participants were shown images of others in distress (e.g. people affected by natural disasters) and non-painful situations (e.g. people out on a picnic). Images of their brains showed lower activation in these brain regions when those in distress belonged to racial groups different from the participants.

Since then, several other studies have substantiated these findings. Depending on the context, this differential processing could be harmless, lead to subtle forms of in-group favouritism or, in extreme cases, to intergroup violence.

Bias doesn’t exist at birth. It is a learned response built on cultural associations together with the brain’s biology. Yet preferential bias towards in-group members doesn’t mean an individual will be hostile towards out-group members. Factors that lead to hostility include the notion of associating an out-group with a threat. Uncertain circumstances — such as those we witnessed during the pandemic — can also heighten mistrust towards the outgroup.

The biology behind “facts of life”

Neuroimaging studies that have explored the basis of intergroup threats have highlighted the role of a specific brain region called the amygdala. An almond-shaped region situated deep in the brain, the amygdala is central to detecting threats and fear-based learning. Imaging studies have shown the amygdala activates to a greater degree when the source of threat is from an out-group member.

In one 2020 study, psychologists imaged the brains of white, non-Muslim participants as they watched short videos of Muslim males with stereotypical appearances threatening their in-group and found this activated the amygdala more, as expected. This study was unique because it also included videos of reconciliatory statements — and watching them activated a very different neural circuit, involving different parts of the cortex, which are higher brain regions that control impulses and regulate emotions. The amygdala being activated by something perceived as a threat is an automatic part of information processing in the brain. But cortical activation implies more of a cognitive effort.

We need more research to better understand neural processing, particularly the extent to which these results are generalisable. A better understanding of the human brains in the context of intergroup threats can also shed light on ways to improve reconciliation.

Whenever you hear social and/or cultural narratives presented as a “fact of life” — that, say, “they are bad people” — and find yourself getting sucked into it, remember that somewhere behind this statement is a misappropriated bit of brain biology. Being aware of our own biology can make us more informed, especially when faced with narratives that arouse rather than inform.

Dr. Reeteka Sud is a neuroscientist by training and a senior scientist at the Center for Brain and Mind, Department of Psychiatry, NIMHANS, Bengaluru.

Evolution is often thought to take over hundreds or thousands of years. But a recent study has found a species of frog which has evolved over within about 25 years. The adaptation was spurred by salt. Researchers collected wood frog eggs from nine populations and allowed them to hatch into tadpoles. Whether populations of tadpoles from more salt-polluted waters had evolved higher salt tolerance was studied. Tadpoles collected from the saltiest wetland experienced a notably longer time until death when exposed to salt than the eight other populations collected from other areas with varying levels of salt, suggesting an evolved tolerance. Frog populations collected from ponds with low and intermediate salt concentrations exhibited similar tolerance curves over a 96-hour exposure. However, the population from a pond with the highest salt concentration exhibited a much higher tolerance. The results provide further evidence that some species of freshwater organisms can evolve tolerance to increasing salinisation, although it may only occur under relatively high concentrations and without trade-offs in growth, development, or behaviour.

Evidence from archaeological sites in the medieval English city of Winchester shows that English red squirrels once served as an important host for Mycobacterium leprae strains that caused leprosy in people according to a study published in the journal Current Biology.

Leprosy is one of the oldest recorded diseases in human history and is still prevalent to this day in Asia, Africa, and South America. “For thousands of years, humans were thought to be the only natural host of M. leprae until the discovery of M. leprae in several wild animals in recent decades, such as armadillos and, more recently, red squirrels and chimpanzees,” the authors write. While scientists have traced the evolutionary history of the mycobacterium that causes it, how it may have spread to people from animals in the past was not known beyond some hints that red squirrels in England may have served as a host.

In the new study, the researchers studied 25 human and 12 squirrel samples to look for M. leprae at two archaeological sites in Winchester. The city was well known for its leprosarium (a hospital for people with leprosy) and connections to the fur trade. In the Middle Ages, squirrel fur was widely used to trim and line garments. Many people also raised them as pets.

The researchers sequenced and reconstructed four genomes representing medieval strains of M. leprae, including one from a red squirrel. An analysis to understand their relationships found that all of them belonged to a single branch on the M. leprae family tree. They also showed a close relationship between the squirrel strain and a newly constructed one isolated from the remains of a medieval person, says a release. The study found that the medieval squirrel strain is more closely related to human strains from medieval Winchester than to modern squirrel strains from England, indicating that the infection was circulating between people and animals in the Middle Ages in a way that hadn’t been detected before.

“These findings on the natural reservoir of M. leprae indicated that M. laprae circulates in more wild animals than we suspected, and zoonotic infection may contribute to the epidemic of leprosy. Therefore, it is inevitable that leprosy epidemics can persist for a long time in the future, and we should remain vigilant against the spread of M. leprae between humans and wildlife,” they write.