And you are not alone: 90% of us use light-emitting electronic devices, such as smartphones and laptops, in the hour before bed, despite the fact that such behaviour is associated with symptoms of insomnia. The obvious solution is to ditch the technology, but people rarely heed this advice.

Knowing that individuals with insomnia are also unlikely to change their ways, researchers from Columbia University Medical Center tested a method to reduce the adverse effects of evening ambient light exposure, while still allowing use of blue light-emitting devices. Their findings will be published in the January issue of Journal of Psychiatric Research.

Blocking blue light

Smartphones, tablets and other light-emitting devices are lit by LEDs, which have a peak wavelength in the blue portion of the spectrum. Blue light at night suppresses melatonin and increases alertness; the use of amber-tinted lenses that block blue light mitigates these effects.

The Columbia team, led by Ari Shechter, PhD, assistant professor of medical sciences, reasoned that selectively blocking blue light in the hours before bedtime would lead to improved sleep in individuals with insomnia.

To test their theory, the researchers recruited 14 individuals with an insomnia diagnosis to take part in a small study. For seven consecutive nights, participants wore wrap-around frames with amber-tinted lenses that blocked blue light or with clear placebo lenses for two hours before bedtime. Four weeks later, participants repeated the protocol with the other set of glasses.

The researchers found that participants got around 30 minutes extra sleep when they wore the amber lenses compared to the clear lenses. In self-reported sleep surveys, participants also reported greater duration, quality, and soundness of sleep, and an overall reduction in insomnia severity.

An affordable solution

These findings are consistent with prior studies showing a benefit of blue-light-blocking lenses in improving sleep, but should be replicated in larger controlled studies, Shechter said.

“Now more than ever we are exposing ourselves to high amounts of blue light before bedtime, which may contribute to or exacerbate sleep problems,” Shechter said. “Amber lenses are affordable and they can easily be combined with other established cognitive and behavioural techniques for insomnia management.”

Many smartphones screens can now be adjusted to emit amber instead of blue light, and Shechter said these settings should help to improve sleep. “I do recommend using the amber setting on smartphones at night, in addition to manually reducing the brightness levels. But blue light does not only come from our phones. It is emitted from televisions, computers, and importantly, from many light bulbs and other LED light sources that are increasingly used in our homes because they are energy-efficient and cost-effective,” he said.

“The glasses approach allows us to filter out blue-wavelength light from all these sources, which might be particularly useful for individuals with sleep difficulties.”

The use of amber lenses also appeared to reduce blood pressure in the study’s participants (these data are published in the September issue of Sleep Medicine). “Insomnia is often characterized by physiologic hyperarousal, which may account for the relationship between poor sleep and cardiovascular risk,” Dr Shechter explained. “Going forward, it will be interesting to examine whether this blue-light blocking approach can be useful for improving cardiovascular outcomes like hypertension in individuals with poor sleep.”

• For more on this topic see our articles Is too much artificial light at night making us sick? and Are we sleep-deprived or just darkness-deprived?

Chief among these is that we are still uncertain of the impacts of nanoparticles in the human body and the environment and that it can be difficult to detect the presence of these toxins with conventional testing.

In a recent study, researchers at the University of Missouri claim to have developed a reliable method for detecting silver nanoparticles in fresh produce and other food products.

“More than 1,000 products on the market are nanotechnology-based products,” said Mengshi Lin, associate professor of food science in the MU College of Agriculture, Food and Natural Resources.

“This is a concern because we do not know the toxicity of the nanoparticles. Our goal is to detect, identify and quantify these nanoparticles in food and food products and study their toxicity as soon as possible.”

Complex technology

Lin and his colleagues used a combination of tests in their study: transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and inductively coupled plasma optical emission spectrometry (ICP-OES)

If it sounds like a mouthful of technology it is – but the properties of nanoparticles are such that no one single test will accurately tell us if they are present, how many are there, what their size, shape and structure is and how deeply the particles have penetrated the food. All of this data is important in understanding their potential toxicity.

You can’t rinse nanoparticles away

With this armoury of technology the research team studied the residue and penetration of silver nanoparticles on pear skin. First, the scientists immersed the pears in a silver nanoparticle solution similar to pesticide application. The pears were then washed and rinsed repeatedly.

Results showed that four days after the treatment and rinsing, silver nanoparticles were still attached to the skin, and the smaller particles were able to penetrate the skin and reach the pear pulp.

Health concerns

“The penetration of silver nanoparticles is dangerous to consumers because they have the ability to relocate in the human body after digestion,” Lin said. “Therefore, smaller nanoparticles may be more harmful to consumers than larger counterparts.”

According to the researchers the use of silver nanoparticles could harm the human body. When ingested, nanoparticles pass into the blood and lymph system, circulate through the body and reach potentially sensitive sites such as the spleen, brain, liver and heart.

More study is needed, they conclude, to better understand the contamination and penetration of different types of nanoparticles on other fruit, crops and agricultural products.

For the small study, which appears in the journal Cyberpsychology, Behavior and Social Networking, researchers at Michigan State University surveyed 319 people on their media use and mental health.

Participants were asked how many hours per week they used two or more of the primary forms of media, which include television, music, cell phones, text messaging, computer and video games, web surfing and others. For the mental health survey, the researchers used well-established measures, although the results do not reflect a clinical diagnosis.

Digital multitasking on the rise

While overall media use among American youth has increased 20% in the past decade, the amount of time spent multitasking with media spiked 120% during that period, the researchers noted.

Things are not much different in the UK.  According to a 2010 Ofcom report, TV, radio and internet take up nearly half our waking lives. One reason for this is the rise in ownership of smart phones which increased by 81% between May 2009 and May 2010, along with the rise of social networks which now account for 23% of all time spent online, compared to 9% in 2007.

The report also found that media multitasking is most popular with 16-24 year olds, with 29% of them using different types of media simultaneously, to cram nine and a half hours of media use into six and a half hours of actual time. Amazingly 12% of over 55s also practised media multitasking.

Looking for cause and effect

“We don’t know whether the media multitasking is causing symptoms of depression and social anxiety, or if it’s that people who are depressed and anxious are turning to media multitasking as a form of distraction from their problems,” said lead author Mark Becker, an assistant professor of psychology at Michigan State University.

On the other hand, depressed or anxious people may be turning to media multitasking to help them deal with their problems.It could also serve as a warning sign that a youngster is becoming depressed or anxious.

Becker added that future research needed to focus on cause and effect.

The findings that have been recently published in the international journal Nanomedicine have health and safety implications for the manufacture, use and ultimate disposal of nanotechnology products and materials.

Many sources of nanoparticles

Environmental pollution including carbon particles emitted by car exhaust, smoking and long term inhalation of dust of various origins have been recognised as risk factors causing chronic inflammation of the lungs. The link between smoking and autoimmune diseases such as rheumatoid arthritis has also been established.

This new research now raises serious concerns in relation to similar risks caused by nanotechnology products which if not handled appropriately may contribute to the generation of new types of airborne pollutants causing risks to global health.

Researchers at Trinity College Dublin’s School of Medicine investigated whether there was a common underlying mechanism contributing to the development of autoimmune diseases in human cells following their exposure to a wide range of nanoparticles containing different physical and chemical properties.

A two pronged approach

The scientists applied a wide range of nanomaterials including ultrafine carbon black, carbon nanotubes and silicon dioxide particles of different sizes, ranging from 20 to 400 nanometres, to human cells derived from the lining of the airway passages, and to the cells of so-called phagocytic origin − those cells that are most frequently exposed to the inhaled foreign particles or are tasked with cleaning up our body from them.

At the same time, collaborating researchers from the Health Effects Laboratory Division, National Institute for Occupational Safety & Health, in West Virginia conducted studies in mice exposed to chronic inhalation of air contaminated with single walled carbon nanotubes.

Triggering autoimmune reactions

The result was clear and convincing: all types of nanoparticles in both the TCD and US study were causing an identical response in human cells and in the lungs of mice, manifesting in the specific transformation of the amino acid arginine into the molecule called citrulline which can lead to the development of autoimmune conditions such as rheumatoid arthritis.

Human proteins which incorporate this modified amino acid as building blocks, can no longer function properly and are subject to destruction and elimination by the bodily defence system.

Once programmed to get rid of citrullinated proteins, the immune system can start attacking its own tissues and organs, causing the autoimmune processes that can result in rheumatoid arthritis.

Commenting on the significance of the findings, lead researcher Professor of Molecular Medicine, Yuri Volkov of Trinity college says: “The research establishes a clear link between autoimmune diseases and nanoparticles. Preventing or interfering with the resulting citrullination process looks therefore as a promising target for the development of future preventative and therapeutic approaches in rheumatoid arthritis and possibly other autoimmune conditions.”