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The world that we live in is filled with sounds, some are comforting and some could be jarring too. But what if the constant noise surrounding us is doing us more harm than we realize? There has been immense research that shows that noise is not just a nuisance, but a silent killer and affects our health in ways we do not even know. There are associations of sound causing heart attacks, type 2 diabetes, and dementia.
Noise is seen as an annoyance, but it effects can go beyond what we imagine. When we hear a sound, it travels through the ear to the brain. This is where it gets processed by the amygdala. It is a region that is responsible for emotional responses. This also triggers a stress response- our heart rate increases, our blood pressure rises, and stress hormones like cortisol flood our system.
This response is also designed to help us react to immediate threats. Especially, if we hear the sound of a predator approaching. However, when we are exposed to constant noise, this response is triggered repeatedly and could compel us to live in a long-term anxious state.
Many studies including Harvard Health and theAmerican College of Cardiology have found associations of noise with health problems including putting a person at a higher risk of cardiovascular diseases such as heart strokes, attacks, and high blood pressure. The constant activation of the stress response can take a toll on the body, increasing inflammation and making it harder for the heart and circulatory system to function properly. Over time, this can lead to serious health conditions like heart disease and diabetes.
Even more troubling, research suggests that noise pollution may contribute to mental health issues. Studies have found a strong connection between exposure to noise and disturbed sleep, which in turn can cause anxiety, depression, and cognitive decline. The World Health Organization estimates that noise contributes to around 12,000 premature deaths annually across Europe alone. This invisible threat, however, is often overlooked because the effects are gradual and cumulative.
One of the most insidious aspects of noise pollution is its impact on sleep. Even when we are asleep, our bodies are not fully immune to the effects of sound. Our ears never fully “turn off,” meaning that even faint noises can disrupt our sleep cycle. Research has shown that people who live in noisy environments—whether near busy roads, airports, or urban centers—often experience fragmented sleep, leading to fatigue and a weakened immune system. Over time, this chronic lack of restful sleep can lead to significant health problems, including an increased risk of developing cognitive disorders such as dementia.
As cities continue to grow, noise pollution is becoming more widespread. Traffic noise, in particular, is one of the most common and harmful sources. The rise of urbanization means more cars, buses, and trains, all of which contribute to an ever-increasing din. This urban soundscape is often relentless, with little respite for those living within it. In densely populated cities, people are exposed to high decibel levels, which can exceed safe thresholds for heart health. In many cases, the sheer volume of sound is not just unpleasant; it’s dangerous.
The solution is not as simple as reducing noise in our immediate surroundings, though efforts to reduce traffic noise and limit industrial sounds are essential. Some cities have taken steps to create quieter spaces by converting busy roads into pedestrian zones or installing noise barriers. These measures have shown to have a positive impact on public health, with research suggesting that even small reductions in noise can prevent premature deaths and improve overall well-being.
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While doctors across the world recommend ensuring that fluoride and other protective minerals make up your toothpaste, your body produces its very own amino acid that protect your entire dental cavity.
Arginine, an amino acid that is already present in saliva, can turn bacteria from damaging to protective in your mouth, a study has found.
When sugars from food are broken down by the many bacteria living in the mouth, acids are produced that gradually damage tooth enamel and lead to cavities. This is known as dental caries. Over time, this acid dissolves tooth enamel and causes cavities.
However, researchers at Aarhus University in Denmark have discovered that regular arginine treatment can significantly reduced the overall acidity levels in the mouth and prevent tooth decay.
Yumi Del Rey, microbiologist at Aarhus, said: ""Our results revealed differences in acidity of the biofilms, with the ones treated with arginine being significantly more protected against acidification caused by sugar metabolism."
Volunteers were then asked to instructed to dip the dentures in a sugar solution for 5 minutes, immediately followed by distilled water (as placebo) or arginine for 30 minutes, one on each side. This was to be repeated three times a day, with arginine treatment done on the same side each time.
Sebastian Schlafer, professor at the Department of Dentistry and Oral Health, explained: "The aim was to investigate the impact of arginine treatment on the acidity, type of bacteria, and the carbohydrate matrix of biofilms from patients with active caries."
After 4 days of this process, the biofilms were developed and the dentures were removed for detailed analysis. The researchers compared dental plaques grown on customized dentures on both sides of each participant's mouth using a special pH-sensitive dye called C-SNARF-4.
Additionally, the team also began to look into how arginine might be reducing acidity, by taking stock of which bacteria and sugars were present in each sample.
Biofilms treated with arginine showed lower levels of a sugar called fucose, while another sugar, galactose, was concentrated towards the outer surface of the biofilm, meaning both sugars were away from the tooth enamel.
After analyzing the DNA of bacteria present, the researchers found that arginine treatment significantly reduced a specific population of Streptococcus bacteria known to produce acid, while slightly increasing other bacterial strains that can metabolize arginine.
The scientists noted that while more research is needed into the arginine's effectiveness, the amino acid could be a promising new addition to oral hygiene products such as toothpaste or mouthwash.
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Covid is returning, as the National Health Service, NHS UK warned that there has been a "bounce back" in respiratory viruses this winter, along with COVID too on the rise. While UK was already struggling with flu and norovirus on the rise, cases of COVID have also risen. The latest data from the UK Health and Security Agency (UKHSA) show that the number of patients in hospital beds with COVID per day has risen from 0.87 per 100,000, as compared with 0.77 per 100,000 the previous week.
NHS national medical director Professor Meghana Pandit said: “It’s clear that the worst is far from over for the NHS this winter, with hospitals again experiencing a rise in patients admitted with flu and other respiratory virus cases last week.”
Since the pandemic, there have been many variants of COVID. The virus has continued to evolve. Two new variants that caused the spike in cases in autumn were XFG, known as Stratus, and NB.1.1, known as Nimbus.
Stratus: It is a subvariant of Omicron variant and made of previous variants LF.7 and LP.8.1.2. It was first detected in a sample on January 27, 2025. Whereas, Nimbus was first detected on January 22, 2025. It also originated from the same omicron variant, which was the reason for spike in 2023.
The World Health Organization (WHO) describes stratus as a "variant under monitoring" after several countries in South East Asia reported a rise in new cases and hospitalizations with this variant being detected.
Among studies that focused on how symptoms appear together, fatigue stood out as the most consistently reported issue. It often occurred alone or alongside problems such as muscle and joint pain, brain fog, or breathlessness. Other symptom pairings that appeared frequently included loss of smell and taste, anxiety with depression, and various forms of musculoskeletal pain.
When researchers classified patients based on affected organ systems, respiratory problems were the most widespread, seen in about 47% of long COVID patients. Neurological symptoms followed at 31%, while gastrointestinal issues were reported by 28%. The authors stressed that these percentages reflect how often these clusters appeared within long COVID cases studied, not how common they are in the general population.
A smaller number of studies sorted patients by how severe their symptoms were, dividing them into mild, moderate, or severe categories using symptom scores, symptom counts, or quality-of-life measures. Three studies used clinical indicators for classification, including abnormal triglyceride levels and signs of restricted lung function on imaging.
As per the Centers for Disease Control and Prevention (CDC), here are the common COVID symptoms:
CDC says, look out for these signs:
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While the National Capital is dealing with cold wave, the air quality also continues to worsen. In several parts of Delhi, the air quality reached severe category. The Indian Meteorological Department (IMD) also issued an Orange alert on Tuesday for cold wave. Dense fog also engulfed the city, with air pollution or the particulate matter being trapped in the air, turning the fog into smog.
The condition of air pollution in Delhi has remained concerning and the levels have spiked to 20 to 30 times above the safety levels recommended by the World Health Organization or the WHO. Many studies, including the official website of the Environmental Protection Agency (EPA), US notes that the small particulate matter found in the air pollution is directly linked to health problems. "Small particles less than 10 micrometers in diameter pose the greatest problems, because they can get deep into your lungs, and some may even get into your bloodstream," notes EPA.
The government is pursuing "smog eating" surfaces to deal with the pollution problem in Delhi. While it may sound like a strange thing in India, not to the world. In fact, in the Netherlands these were used to reduce local nitrogen oxide or the NO concentrations in the air, rather than greenhouse gas concentrations.
Smog usually contains a mixture of hydrocarbons, ozone, oxides of nitrogen and sulphur, and particulates. The pollution is caused by both photochemical reactions that involve sunlight, unburned hydrocarbons and nitrogen oxides, along with high concentrations of particulate matter, especially from vehicle exhaust, construction dust and biomass burning.
Environment Minister Manjinder Singh Sirsa announced "smog eating" surface as part of its pollution control plan, for which the government has also signed an MoU with IIT Madras.
The smog eating surfaces will be public surfaces coated with photocatalytic materials like titanium dioxide or TiO2 that is used to degrade pollutants.
The Deccan Herald quoted Dr Pradeep Singh, professor and head at the School of Advanced Chemical Sciences, Shoolini University, who explained: Photocatalytic materials are basically semiconductors. Substances like TiO2₂or zinc oxide are typically used as photocatalysts. When light falls on these semiconductor catalysts, electrons within them jump from one energy level to another, creating a hole. These photocatalytic holes and electrons subsequently form free radicals, which have strong oxidizing properties and can break down certain air pollutants with which they interact."
Smog contains mainly nitric oxide, nitrogen dioxide, sulphur dioxide, ozone, and particulate matter. When all of these interact with photocatalytic materials, gaseous pollutants convert into less harmful compounds, such as nitrogen oxides become nitrates or decompose into ions. This process is also known as pollutant mineralization.
Fun Fact: It was in 2017, when scientists in Italy developed a type of photocatalytic cement that could absorb pollutants and convert it into harmless salts. Palazzo Italia in Milan, opened in 2015, was the first building to use the cement.
As per Dr Ashish Moon, Head of the Civil Department at Smt Radhikatai Pandav College of Engineering, Nagpur, the impact depends on environmental conditions. He explained that titanium dioxide can locally reduce certain gaseous pollutants like nitrogen oxides under ideal conditions, rather than absorbing up to 50 percent of all harmful gases.
He also co-authored a paper in 2021, titled: Detailed Case Study on Smog Eating Tile, where he noted, "It is better to use it in liquid form than a powder. I have not come across any harmful interactions between TiO2 and particles or gases in the air." However, he also points out that how it will work in Delhi will depend on its weather conditions and atmosphere. "There should be enough UV light for the nanoparticles to activate," he said.
Will this arrangement really work? That is yet to see, although a 2023 Spanish study found that although this measure showed some improvement, but it only yielded a modest reduction in ambient NO2. We are yet to see how well it will work in Delhi and its neighboring city's pollution problem.
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