Exercising for 5 minutes a day can reduce the risk of dementia by 41%; brewing tea can remove heavy metals in water | Technology Weekly

Compiled by Zhou Shuyi and Pingsheng

Some antidepressants may worsen cognitive decline in dementia patients

A type of antidepressant (selective serotonin reuptake inhibitor, or SSRI) is associated with faster cognitive decline in people with dementia, according to a study published February 25 in BMC Medicine. The authors suggest that further research is needed to assess differences in risk for dementia among different antidepressant classes.

Antidepressants are widely used in patients with dementia to improve neuropsychiatric symptoms such as anxiety, depression, aggressive behavior and sleep disorders. Sara Garcia Ptacek, the author of the paper, said, "Depressive symptoms can both exacerbate cognitive decline and impair quality of life, so their treatment is crucial. Our findings can help medical staff choose more appropriate antidepressant drugs for patients with dementia."

Between 2007 and 2018, researchers conducted a population-based cohort study in Sweden, including 18,740 patients with dementia with an average age of 78.2 years. The researchers assessed patients' cognitive functions such as orientation and short-term memory using the Mini-Mental State Examination (MMSE). SSRI was the most common antidepressant in the study cohort, accounting for 64.8% of all antidepressant prescriptions.

The results showed that high doses of SSRIs were associated with an increased risk of severe dementia. SSRI intake of more than 1 DDD (defined daily dose, the average dose of commonly prescribed drugs) was associated with an additional decline in cognitive scores of 0.42 points per year. Among them, escitalopram was associated with the fastest cognitive decline, followed by citalopram and sertraline. This association was stronger in patients with severe dementia. The study also found that patients with dementia who took at least one SSRI at the time of diagnosis or thereafter had a higher risk of fractures and all-cause mortality. Compared with women, men had a faster decline in cognitive ability when taking antidepressants.

The authors caution that the severity of dementia in individual patients may independently contribute to cognitive decline, making it difficult to attribute the observed effects solely to antidepressant use. They add that future research is needed to elucidate the interaction between specific antidepressants and the rate of cognitive decline in people with dementia.

Artificial sweeteners may harm blood vessel health

From diet soda to zero-sugar ice cream, artificial sweeteners have been touted as burden-free alternatives to sugar. However, a study published in Cell Metabolism on February 20 shows that a widely used artificial sweetener, aspartame, may have adverse effects on vascular health.

The research team found that aspartame can drive up insulin levels in animals. This change can further promote atherosclerosis, the accumulation of fatty plaques in the arteries. Over time, this accumulation can lead to increased inflammation levels and significantly increase the risk of heart attack and stroke.

The researchers fed mice a diet containing 0.15% aspartame every day for 12 weeks, which is equivalent to three cans of diet soda a day for humans. Compared with mice not fed the sweetener, mice fed aspartame developed larger and more fatty plaques in their arteries and showed higher levels of inflammation, both markers of impaired cardiovascular health.

The experiment showed that after aspartame entered the mice's bodies, the insulin levels in their blood surged. The authors of the paper pointed out that this result is not surprising considering that our mouths, intestines and other tissues are full of sweet taste detection receptors that guide insulin release - aspartame, which is 200 times sweeter than sucrose, seems to trick the receptors into releasing more insulin.

Further studies have shown that increased insulin levels in mice directly promote the formation of fatty plaques in the arteries, indicating that insulin may be an important factor in the relationship between aspartame and cardiovascular health. On this basis, they explored the mechanism by which increased insulin levels lead to the formation of arterial plaques and locked in an immune signaling molecule called CX3CL1. This signaling molecule shows significant activity under the stimulation of insulin, thus playing a key role in the formation of arterial plaques.

"Blood flow within arteries is powerful, and most chemicals are usually quickly washed away when the heart beats," the authors explain. "Surprisingly, however, CX3CL1 is not washed away. It remains firmly attached to the surface of the blood vessel lining, acting like a bait that captures and gathers immune cells as they pass by." Many of these trapped immune cells can cause vascular inflammation.

In the future, the research team plans to verify their findings in humans. They also pointed out that given that vascular inflammation is closely related to a variety of chronic diseases such as stroke, arthritis and diabetes, CX3CL1 is also expected to become a potential therapeutic target for other chronic diseases besides cardiovascular disease.

Study finds that brewing tea can remove heavy metals from water

Drinking tea in moderation is good for your health, and it's not just because of the flavor compounds in it - a new study published in ACS Food Science & Technology on February 25 confirmed that tea can absorb heavy metals such as lead and cadmium when brewed, thereby purifying water quality.

"Tea leaves have a highly active surface, which is a useful property for adsorbent materials and is why they release flavor chemicals quickly into water," said Benjamin Shindel, an author on the paper. "You don't need to do anything else, you just put the tea leaves in water and they will naturally remove the metals."

Scanning electron microscope image of black tea leaves, magnified 300 times. The wrinkled surface of the tea leaves increases the adsorption area. | Vinayak P. David Group/Northwestern University

The new study explored the effects of different types of tea leaves, tea bags, and brewing methods on the adsorption of heavy metals. The results showed that black tea can reduce the concentration of all tested heavy metal ions, including lead, chromium, and cadmium. The longer the brewing time and the higher the water temperature, the better the adsorption effect. Brewing black tea for 5 minutes can reduce the concentration of lead ions in water by about 15%. In addition, broken tea has a better adsorption effect than whole tea leaves. The effects of black tea, green tea, and white tea are better than chamomile tea, rooibos tea, and oolong tea. Cellulose tea bags are better than cotton and nylon tea bags.

Professor Michelle Francl of Bryn Mawr College in the United States warned, "If you are worried about heavy metals in your water, don't think drinking tea will solve the problem." However, she added that the research "suggests some interesting directions" that will help develop practical methods to remove pollutants from water, which is an urgent need in many parts of the world.

Mars once had beaches and oceans

Mars may have once been a place with drenching sunshine, soft sandy beaches and gentle ocean waves, according to a new study published in PNAS on February 24.

A large number of studies based on remote sensing images have previously found typical flowing water features such as dry riverbeds, alluvial fans and deltas on the surface of Mars, indicating that there may have been a large amount of liquid water in the history of Mars. However, there has been controversy over whether there was an ancient ocean in the northern lowlands of Mars. This is mainly because the ancient coastline height distribution inferred from remote sensing data is inconsistent, and the impact, weathering and reshaping processes that the surface of Mars has experienced over the past 4 billion years have obscured direct surface evidence.

Schematic diagram of the formation process of the underground inclined sedimentary terrain at the landing site of "Zhurong". A, layered structure formed by tidal action; B, as the ancient coastline retreated, liquid water disappeared and sedimentation stopped. Subsequently, long-term physical and chemical weathering changed the properties of rocks and minerals, forming the Martian surface layer, resulting in the sediments being covered by the current Martian surface soil.

An international research team used data from the Zhurong Mars rover to identify a series of reflectors with dips of 6°-20° at depths of 10-35 meters underground, which are continuously distributed over 1.3 kilometers and all tilted toward the northern lowlands. These structures are highly consistent with the characteristics of Earth's coastal sediments, and their consistency and physical properties exclude other causes such as aeolian sand piles, lava tubes or river alluvial deposits. The large-scale presence of these sediments indicates that wind-wave-driven coastal transport provides a stable net inflow of sediment to the coastline and forms a coastline foreset layer, a structure that can only be formed in a persistent and stable large-scale water environment, rather than just a local and short-lived meltwater phenomenon. This study not only provides key underground evidence of the existence of an ancient ocean on the northern plains of Mars, but also reveals that Mars once experienced a long period of warm and humid climate, which means that Mars has maintained temperature and pressure conditions suitable for the existence of liquid water for a long time.

An artist's impression of Mars 3.6 billion years ago. The blue area shows the now-vanished Deuteronilus ancient ocean and coastline. Orange star: Vulcan rover landing site; yellow star: Perseverance rover landing site. | Robert Citron

The authors of the paper said that the greatest significance of this discovery is that it extends the evidence of liquid water on Mars from the remote polar regions to the mid- and low-latitude regions that are more suitable for human activities. If there was an ocean here, then with climate change, a large amount of water may have been sealed in the form of underground ice, providing the possibility of water resource utilization for future Mars bases.

Exercising for 5 minutes a day can reduce the risk of dementia by 41%

A new study from Johns Hopkins University in the United States found that about 35 minutes of moderate to vigorous intensity exercise per week can reduce the risk of dementia in middle-aged and elderly people by 41%.

The research team published a paper in the Journal of the American Medical Directors Association, saying that they used data from a large long-term survey in the UK to analyze the association between the exercise habits of nearly 90,000 adults and the risk of dementia within a few years, and came to the above conclusion. Most of these people were over 50 years old and used sports bracelets to record their exercise time between 2013 and 2015. During the average 4.4 years of follow-up survey, 735 people were diagnosed with dementia.

The analysis showed that the longer the daily exercise, the greater the reduction in dementia risk. Compared with no exercise at all, exercising for 35 to 70 minutes a week can reduce the risk of dementia by 60%, 70 to 140 minutes by 63%, and more than 140 minutes by 69%. The researchers said this means that even if a person only exercises for 5 minutes a day, it will have a significant effect.

Dementia, represented by Alzheimer's disease, is one of the main reasons for the decline in the quality of life of the elderly, and there is currently no effective treatment. The medical community has previously proposed that a healthy lifestyle can help prevent dementia, but it is not clear what the minimum amount of exercise is to produce a significant effect. (Xinhua News Agency)

Brain-computer interface that can "co-evolve" with the brain

In a paper published in Nature Electronics on February 17, researchers developed a new brain-computer interface solution based on memristor brain-like computing chips, achieving long-term, stable, efficient, and high-precision EEG decoding and brain-computer co-evolution.

Traditional brain-computer interfaces face two major challenges: the human brain is a complex dynamic system, and EEG signals have strong variability, which makes the long-term mutual adaptability between the brain and the machine weak and the working performance seriously degrades over time; at the same time, with the expansion of application scenarios, the number of channels for EEG signal acquisition has increased dramatically, and the decoding algorithm has become more complex, bringing huge challenges to efficient and real-time EEG processing.

The team developed a 128Kb memristor chip as an adaptive EEG decoder and built a complete brain-computer interface system. The memristor chip adopts a single-step decoding strategy, which reduces the computational complexity by 6.5 times and reduces the impact of the non-ideal characteristics of the memristor on the computational accuracy. Compared with the traditional CPU solution, the normalized decoding speed of the memristor chip solution is increased by 2 orders of magnitude and the energy consumption is reduced by 3 orders of magnitude. The team also developed an interactive update framework, using error-related potential (ErrP) as the brain's feedback signal for the memristor decoding results. During the experiment, new samples are dynamically accumulated to update the memristor decoder, so that it can co-evolve and adapt to the dynamically changing brain signals. In a human-computer interaction experiment involving ten subjects and lasting an average of six hours, the decoding accuracy of the brain-computer interface with co-evolution capability was about 20% higher than that of the traditional interface. In this experiment, the contribution ratio of the brain and the decoder showed dynamic changes: in the early stage, the decoder was mainly updated adaptively, and as time went on, the brain's contribution gradually increased, and finally reached a dynamic balance between the two, demonstrating the process of brain-computer co-evolution.

Using a new brain-computer interface, real-time brain-controlled drone flight | Nature Electronics

The researchers said: "This study proposed the concept of brain-computer co-evolution for the first time. By utilizing the high energy efficiency of memristors, which integrates storage and computing and conductance in-situ updating, adaptive EEG decoding based on brain-like chips has made breakthrough progress in hardware efficiency and decoding accuracy. It is not only suitable for various brain-computer interface systems, but can also be expanded to other application fields such as neural regulation, motor rehabilitation, and virtual reality."

AI industry observations of the week

The Lancet Digital Health: "AI-assisted screening has significantly improved cancer detection rates and has crossed the critical point of changing breast cancer screening practices, and double-reading may become history."

The MASAI trial is the world's first randomized controlled trial evaluating AI-assisted mammography, which was conducted in the Swedish Breast Cancer Screening Program. A new study analyzed 105,915 participants in the MASAI trial and found that compared with the standard two-person reading of radiologists, AI-assisted screening increased the cancer detection rate by 29% (6.4 cases per 1,000 people vs. 5.0 cases per 1,000 people, P=0.0021), and the early detection rate of invasive cancer increased by 24%; the recall rate and false positive rate increased slightly, but not significantly. In addition, the AI-assisted strategy also reduced the workload of doctors in reading films by 44.3%.

Microsoft CEO Satya Nadella: "If we say this is like the Industrial Revolution, then we need to achieve Industrial Revolution-like growth. ... We claim to have achieved some AGI (general artificial intelligence) milestones, but in my opinion, this is just a meaningless numbers game. The real benchmark should be: the world economy grows at a rate of 10%."

Nadella said in a February 19 podcast interview that he is tired of the hype surrounding AGI.

xAI: “Grok 3 is now available for free (until our servers crash).”

On February 20, Elon Musk's AI company xAI stated on social media X that its artificial intelligence Grok 3 will be open to all users for free.

Anthropic: "Claude 3.7 Sonnet shows particularly significant improvements in programming and front-end web development."

On February 25, Anthropic released the world's first "hybrid reasoning model" Claude 3.7 Sonnet, which can provide near-instant responses and also display detailed step-by-step thinking processes, thereby improving performance in mathematics, physics, instruction following, programming, etc. In addition, the Claude Code command-line tool launched simultaneously can help developers complete a series of engineering tasks, supporting operations such as searching and editing code, running tests, and submitting code to GitHub.

OpenAI CEO Sam Altman: "The good news is that this is the first model that makes me feel like I'm talking to a thoughtful person. There were several times when I leaned back in my chair and was amazed at the truly useful advice I could get from the AI. The bad news is that this model is big and expensive."

On February 27, OpenAI released a research preview of GPT-4.5, calling it OpenAI's largest and best chat model to date. With the help of unsupervised learning, GPT-4.5's interactive experience is more natural, more knowledgeable, more considerate, and shows a higher "emotional intelligence".

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