Ultrasonic whispers

Ultrasonic whispers


A group of Chinese-American scientists at the University of Pennsylvania has figured out a way to deliver audio (music, podcasts and so on) right into your ear, without you having to wear earbuds or headphones, even as those around you cannot hear any of it.

The challenge of delivering audible content to a targeted listener has flummoxed sound engineers but a breakthrough, which still requires some fine-tuning, has been achieved.

Suppose you want to listen to a podcast. The audio file is stored in the car’s stereo system. The stereo system converts the podcast’s regular audio waves into ultrasonic signals — these signals are inaudible because they’re too high-pitched for human ears. However, the ultrasonic waves are so carefully aimed that they cross each other right where your head is — and they become audible sounds.

As long as your head — and ear — is in the ‘audio bubble’, you will hear the podcast. If you move your head, you will hear nothing.

The sound quality isn’t perfect yet. The scientists are working with machine learning techniques to improve the technology, according to a PNAS paper. Yun Jing, who led the research, believes that the technology has some interesting applications, ranging from home theatres to device-free communications.

Some caution that ultrasounds may harm your ear — but that’s another matter.

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Published on June 1, 2025



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Can hospital visits help predict the risk of suicide?

Can hospital visits help predict the risk of suicide?


TIMELY AID: Healthcare settings play a critical role in suicide prevention
| Photo Credit:
Abdullah Durmaz

Death by suicide is not only a tragic loss of life but also leaves a searing impact on families.

A paper published late last year in the NPJ Mental Health journal showed that probability and machine-learning models built using logistic regression and random forest concepts can predict suicide risk better than existing methods.

A logistic regression estimates the probability of an event occurring, while a random forest model is a machine-learning algorithm that uses an ensemble of ‘decision trees’ to make predictions.

Researcher Roy Adams and others used electronic health record data in the US to test these models, which were able to predict suicide risk 83 per cent of the time, as compared with 64 per cent in the case of the screening methods currently used in the West. A 50 per cent success is as good as leaving things to chance.

The authors emphasise that healthcare settings play a critical role in suicide prevention, noting that about 72 per cent of suicide attempts and 50 per cent of suicide deaths happened within 90 days of contact with the health system. This, they say, highlights the scope for intervention within these settings.

Age factor

The study analysed health record data from over 3,31,000 visits by more than 16,000 adults to American-Indian health service providers between 2017 and 2021. In this period, there were 417 suicide attempts and 37 deaths by suicide.

The study found that suicide attempt or death was associated with younger age, a diagnosis of depression, anxiety, bipolar disorder, post-traumatic stress disorder or suicidal ideation, a diagnosis related to alcohol, cannabis or other substance abuse, and a past positive screen for intimate partner violence, suicide risk or depression.

Though the study was intended to help reduce suicide risk among American-Indian and Alaska Native populations, the approach could well apply to India, which has the highest number of suicides in the world and needs timely and targeted interventions to help save lives.

Deaths by suicide increased from 9.9 per one lakh population in India to 10.4 between 2017 and 2019, and then further to 12.4 by 2022, according to the National Crime Records Bureau data. The latest data show that nearly 34 per cent of suicides was in the 15-30 age group.

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Published on June 1, 2025



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Future of data centres: It’s all in the DNA

Future of data centres: It’s all in the DNA


Imagine a large data centre of this kind: it has no semiconductor chips, it consumes no energy, its land footprint is small, and yet it stores far more information than any of today’s hyperscale data centres. Instead of semiconductors, it has hundreds of vials holding a liquid — an aqueous solution of DNA molecules.

Sounds far-fetched, like science fiction? Think again. Later this month, an interesting conference is to be held at the Sarbonne University, Paris, titled ‘Storage and computing with DNA, 2025’. If you break it down to its components — DNA storage and DNA computing — you are looking at a fascinating future of information technology, one built without semiconductors and with only factory-made DNA.

Storing data — and, by extension, computing — in the form of DNA is not a new idea. As a concept, it has been around for over half a century and, as a technology, for a dozen years. As a group of Chinese scientists note in a paper published in Synthetic and Systems Biology, the idea of using DNA for data storage was outlined independently by two scientists — Norbert Wiener of the US and Mikhail Neiman (erstwhile USSR) — almost at the same time at the release of IBM’s first hard disk in the 1960s.

Evolving technology

In 2012, a team led by George Church, a professor of genetics at Harvard Medical School and a founding core faculty member of the Wyss Institute, successfully encoded his book Regenesis: How synthetic biology will reinvent nature and ourselves into DNA. This project demonstrated the potential of DNA as a high-density, long-term data storage medium. In 2020, at the University of Texas at Austin, a research team that included scientist Stephen Jones and molecular biologist Ilya Finkelstein encoded the novel The Wonderful Wizard of Oz into DNA. They developed an advanced error-correction method for accurate retrieval of data even under harsh conditions.

Information storage is all about coding. In the past, messages transmitted using Morse code involved the use of dots and dashes to represent the letters of the alphabet — so, for instance, you have three dots for ‘s’; three dashes for ‘o’; and a combination of three dots, three dashes, and three dots for ‘SOS’.

In the computing era, coding involves combinations of zeroes and ones.

Coding using DNA molecules relies on their twisted ladder structure, where sugars and phosphate molecules form the rails, and pairs of nucleotides — adenine (A), thymine (T), cytosine (C) and guanine (G) — form the rungs. The nucleotides can stand in for the dots and dashes in Morse code, since A will only pair with T, and C only with G. Information can be stored as combinations of A-Ts and C-Gs. Since DNA can be synthesised, you can make any DNA of your choice to store data.

As such, DNA storage is not futuristic, but an evolving technology. The problem essentially has to do with the cost of synthesising DNA — $3,500 for 1 megabyte of information, according to one estimate. However, the cost is coming down, as is the ease of synthesising DNA. People are even talking of bench-top DNA synthesisers, the size of a mini fridge.

So, are we looking at an era of ‘DNA data centres’?

Karthik Raman, Professor of Data Science and AI, Department of Biotechnology, IIT-Madras, says it is “definitely possible” although a lot more work is needed.

The proof-of-concept has been established, he says.

Microsoft, which plans to spend $80 billion to build data centres in 2025, has been working on DNA data centres for some years. “Using DNA to archive data is an attractive possibility because it is extremely dense — up to about 1 exabyte per cubic millimetre,” Microsoft said a decade ago. “While this is not practical yet due to the current state of DNA synthesis and sequencing, these technologies are improving quite rapidly with advances in the biotech industry.”

Perhaps the “not practical yet” factor still holds. While DNA synthesising is getting cheaper (sequencing is already very cheap), there are other concerns, such as lack of accuracy — there is a one per cent chance that a nucleotide combination may not represent the data correctly. And one must also factor in the energy involved in synthesising DNA, though it is likely to be far less than what current data centres consume.

DNA computing

If DNA storage is here, can ‘DNA computing’ be far behind? However, the concept of a liquid computer powered by DNA is still an emerging one. A recent article speculates on the development of a DNA-powered supercomputer capable of (say) 100 billion tasks at once.

DNA storage and computing is the ‘watch this space’ area of technology, whose implications are unimaginable.

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Published on June 1, 2025



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Efficient effluent treatment through photocatalysis

Efficient effluent treatment through photocatalysis


The release of industrial chemical waste into waterbodies is a global concern; the approach to tackling this has generally involved the use of catalytic materials that rely on sunlight to drive chemical reactions. However, most photocatalysts are difficult to reuse, limiting their practicality in largescale applications. Further, these catalysts require ultraviolet (UV) light to drive the conversions, which necessitates dedicated UV sources, adding to the complexity and cost of the system.

A team of researchers at NIT-Rourkela, led by Prof Subhankar Paul of the Biotechnology and Medical Engineering department, has developed an innovative photocatalyst system.

The system combines iron-doped nano-titania with graphene oxide and immobilises the compound on specially designed spherical concrete beads.

These beads are made from green concrete using coal fly ash derived zeolite, a sustainable approach that repurposes industrial waste and offers high mechanical strength, porosity and absorption capacity. This composite material uses sunlight to break down toxic pollutants in wastewater efficiently.

The photocatalyst beads can be added to the wastewater reservoir, exposed to sunlight and easily removed once the water treatment is complete.

Since the developed technology does not rely on external energy sources, it can be used easily in rural and resource- constrained areas.

This technology has the potential to treat industrial effluents, municipal wastewater and contaminated natural water sources.

“As the global concerns over water pollution continue to grow, this NIT- Rourkela innovation provides a timely and sustainable response to address the challenge,” says a press release from the institute.

Eco-safe lubrication

Lubrication reduces friction and wear in machinery, ensuring efficiency and longevity. Conventional mineral or synthetic oil-based lubricants pose environmental risks, driving the demand for sustainable alternatives. Scientists at the Institute of Advanced Study in Science and Technology (IASST), Guwahati, have developed an environmentally friendly lubricant formulation that significantly enhances friction reduction, wear resistance and overall performance. The lubricant has been developed by integrating surface-modified graphitic carbon nitride into bio-based castor oil.

This advancement offers a sustainable alternative to conventional lubricants, addressing both efficiency and environmental concerns.

A study of friction, lubrication and wear of interacting surfaces in relative motion (tribological evaluations) demonstrated remarkable improvements — reduction of friction by around 54 per cent and decrease of wear volume by 60.02 per cent compared to castor oil alone. The lubricant also exhibited a higher load-bearing capacity and greater thermal stability, with the oxidation onset temperature rising from 320 degree C to 339 degree C, demonstrating the efficiency of the lubricating formulation. Further, toxicity assessments confirm minimal formation of free radicals (thereby curbing secondary reactions), making the formulation safe for environmentally sensitive applications.

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Published on June 1, 2025



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Why even BSNL wants to take a nuclear plunge

Why even BSNL wants to take a nuclear plunge


CROSSED LINES: With its telecom business tottering, State-owned BSNL eyes options
| Photo Credit:
SUBRAMANIUM S

The adage “small is beautiful” is finding new relevance in India’s nuclear energy sector, drawing in even rank outsiders to explore the technology. Bharat Sanchar Nigam Ltd (BSNL), the State-owned telecom giant, which is tottering in its own business, has expressed interest in the field.

Yes, you read it right. BSNL wants to take a nuclear plunge.

BSNL is among several entities responding to a ‘request for proposal’ (RFP) issued by the Nuclear Power Corporation of India Ltd (NPCIL) for setting up two 220 MW Bharat Small Reactors (BSRs) as captive power units.

In its response, BSNL submitted several queries, including whether reactors of capacity below 220 MW can be installed, the minimum land requirement, the feasibility of using urban land for the plant, entitlement to carbon credits and potential government funding support.

Terms of business

NPCIL clarified that the proposed reactor capacity is fixed at 220 MW, and land requirements are detailed in the RFP. The suitability of city sites would be evaluated by the Atomic Energy Regulatory Board (AERB). Regarding funding, NPCIL stated that financing is the responsibility of the project developer, while it remained silent on carbon credit entitlements.

For now, BSNL and others interested in smaller capacities will have to wait. India is still developing next-generation technologies, like the 50 MW Bharat Small Modular Reactor (BSMR), a 5 MW (approximately 2 MWe) gas-cooled micro modular reactor (GCMMR), and other innovations, as part of its broader goal of achieving 100 GW of nuclear power by 2047.

India Inc’s interest

Meanwhile, the RFP has drawn interest from a wide spectrum of India’s public and private sector groups/corporates, including the Indian Railways (via REMC Ltd), Tata, Reliance, Adani, Aditya Birla, Torrent, Vedanta, Godrej, JSW, ITC and BHEL.

Nearly 687 queries have been submitted.

Some of the key issues raised include:

Transfer of ownership of the nuclear asset to NPCIL for a token amount of ₹1, and its implications on financing and taxation.

The RFP’s reliance on data from a 15-year-old 2×200 MW plant in Rajasthan, which cost ₹2,361.81 crore, for project cost estimation (NPCIL responded that updated data would be shared after the signing of a non-disclosure agreement).

Reduction of the exclusion zone from 1 km to 0.5 km, and its utilisation (NPCIL clarified that the land could be used for solar/wind power projects, subject to hazard assessments and regulatory approval).

High cost of operations and maintenance, including the need for developers to meet the cost of spent fuel management, even though the fuel remains the Department of Atomic Energy’s property.

Expertise fee of 60 paise per kWh payable to NPCIL.

NPCIL will be the plant operator under the Civil Liability for Nuclear Damage Act, 2010, and will handle compliance through insurance or financial security, reimbursable by the promoter.

Low plant load factor (PLF) of 68.5 per cent mentioned in the RFP (NPCIL stated this is expected to be revised to 72.5 per cent, and actual performance is likely to be higher, based on historical data).

NPCIL also clarified that project promoters may propose multiple locations across different States; additionally, an amendment to the Electricity Rules to allow captive consumption of nuclear power is under consideration.

It will be interesting to see how many of the business groups will go ahead, even as some argue that the RFP conditions are loaded in favour of NPCIL.

(The writer is a senior business journalist based in Chennai)

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Published on June 1, 2025



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Dr M R Srinivasan, renowned nuclear scientist, passes away at 95

Dr M R Srinivasan, renowned nuclear scientist, passes away at 95


Around the time the India-US civil nuclear agreement was being hammered out, this writer was witness to an unusual incident, at a meeting organised by the Triplicane Cultural Academy, Chennai, on the agreement. Two tall individuals, both highly accomplished in their fields, got into a heated personal exchange on the dais, in full view of the audience. One was the celebrated bureaucrat, B S Raghavan; the other was Dr M R Srinivasan, former Chairman, Atomic Energy Commission. The two had never met before. Raghavan was completely against the proposed agreement with the US, fearing “swarms of inspectors” from the US nosing around India’s nuclear power plants. Srinivasan, the principal speaker of the evening, on the other hand, was fully in favor of the agreement. 

As Raghavan was speaking, Srinivasan fidgeted uneasily and smiled, as though saying, “oh, this man does not understand the nuclear deal”, but as Raghavan went on and on, Srinivasan got visibly angry and told the speaker to stop, and not to try to hijack the proceedings. Raghavan told Srinivasan that he was 80 and “standing next to God” and had no desire to hog the limelight and continued with his speech. 

When Raghavan finished his speech and took his seat, Srinivasan gave him a friendly smile, shook hands with him and said, “we like to spar, don’t we?” 

This incident gives a glimpse into the mind of Malur Ramasamy Srinivasan (and indeed of Bahukutumbi Srinivasa Raghavan) who breathed his last this morning, at the ripe age of 95. (Raghavan passed away last year.) Srinivasan, who was as affable as he was intensely intellectual, was not one given to impulsive fulminations, but he could not stand someone try to stop a development that he believed was in India’s favor. On that evening, his love for his country got the better of his cool. 

Immense contributions

From the time Srinivasan joined the Department of Atomic Energy in 1955, as a young man of 25, armed with a fresh PhD in physics from McGill University, Montreal, Canada, till his technical superannuation as the Chairman of Atomic Energy Commission in 1990, his contributions were everywhere in the nuclear energy space. He was, for instance, involved in the building India’s first nuclear reactor, Apsara. Though after his retirement, Srinivasan took up residence in the pristine hills of Ooty, Tamil Nadu, (where he continued to live till his passing today), he was actively involved in public life for many years, such as Member, (erstwhile) Planning Commission (1996-98) and Member, National Security Advisory Board (2002-04 and 2006-08). 

Much of what we see in India’s nuclear energy sector today owes its existence to Srinivasan. Kamlesh Nilkanth Vyas, another former Chairman of AEC, observes that Srinivasan contributed immensely to India’s nuclear energy program in its formative years, working alongside the legendary nuclear scientist, Dr Homi Bhabha. In 1974, Srinivasan was appointed as Director, Power Projects Engineering Division, Department of Atomic Energy; he successfully lobbied for converting the division into Nuclear Power Board, which later, in 1987, became the Nuclear Power Corporation of India Ltd, with Srinivasan as its Founder-Chairman. Vyas told businessline today Srinivasan was involved in thinking behind India and Russia for setting up nuclear power plants in India—the 2×1000 MW Kudankulam Nuclear Power Plant is a result of that thinking. 

Srinivasan is survived by his wife Geetha and their daughter, Sharada. Srinivasan, a recipient of several awards and honours, was recognised for his services by the government of India, which gave him the Padma Vibhushan award, the country’s second highest civilian award, in 2015. 

 

Published on May 20, 2025



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