Anti-depressants’ ‘link to diabetes’

People prescribed anti-depressants should be aware they could be at increased risk of type 2 diabetes, say UK researchers.

The University of Southampton team looked at available medical studies and found evidence the two were linked.


But there was no proof that one necessarily caused the other.

It may be that people taking anti-depressants put on weight which, in turn, increases their diabetes risk, the team told Diabetes Care journal.

Or the drugs themselves may interfere with blood sugar control.

 “Start Quote

These findings fall short of being strong evidence that taking anti-depressants directly increases risk of type 2 diabetes”

Dr Matthew Hobbs of Diabetes UK

Their analysis of 22 studies involving thousands of patients on anti-depressants could not single out any class of drug or type of person as high risk.

Prof Richard Holt and colleagues say more research is needed to investigate what factors lie behind the findings.

And they say doctors should keep a closer check for early warning signs of diabetes in patients who have been prescribed these drugs.

With 46 million anti-depressant prescriptions a year in the UK, this potential increased risk is worrying, they say.

Prof Holt said: “Some of this may be coincidence but there’s a signal that people who are being treated with anti-depressants then have an increased risk of going on to develop diabetes.

“We need to think about screening and look at means to reduce that risk.”

Diabetes is easy to diagnose with a blood test, and Prof Holt says this ought to be part of a doctor’s consultation.

“Diabetes is potentially preventable by changing your diet and being more physically active.

“Physical activity is also good for your mental health so there’s a double reason to be thinking about lifestyle changes.”

Around three million people in the UK are thought to have diabetes, with most cases being type 2.

Dr Matthew Hobbs of Diabetes UK, said: “These findings fall short of being strong evidence that taking anti-depressants directly increases risk of type 2 diabetes. In this review, even the studies that did suggest a link showed only a small effect and just because two things tend to occur together, it doesn’t necessarily mean that one is causing the other.

“But what is clear is that some anti-depressants lead to weight gain and that putting on weight increases risk of type 2 diabetes. Anyone who is currently taking, or considering taking, anti-depressants and is concerned about this should discuss their concerns with their GP.”

Source: BBC

‘Sugar gel’ helps premature babies

A dose of sugar given as a gel rubbed into the inside of the cheek is a cheap and effective way to protect premature babies against brain damage, say experts.

Dangerously low blood sugar affects about one in 10 babies born too early. Untreated, it can cause permanent harm.

Researchers from New Zealand tested the gel therapy in 242 babies under their care and, based on the results, say it should now be a first-line treatment.

Their work is published in The Lancet.

Sugar dose

Dextrose gel treatment costs just over £1 per baby and is simpler to administer than glucose via a drip, say Prof Jane Harding and her team at the University of Auckland.

 “Start Quote

This is a cost effective treatment and could reduce admissions to intensive care services which are already working at high capacity levels”

Andy ColeBliss

Current treatment typically involves extra feeding and repeated blood tests to measure blood sugar levels.

But many babies are admitted to intensive care and given intravenous glucose because their blood sugar remains low – a condition doctors call hypoglycaemia.

The study assessed whether treatment with dextrose gel was more effective than feeding alone at reversing hypoglycaemia.


Neil Marlow, from the Institute for Women’s Health at University College London, said that although dextrose gel had fallen into disuse, these findings suggested it should be resurrected as a treatment.

We now had high-quality evidence that it was of value, he said.

Andy Cole, chief executive of premature baby charity Bliss, said: “This is a very interesting piece of new research and we always welcome anything that has the potential to improve outcomes for babies born premature or sick.

“This is a cost-effective treatment and could reduce admissions to intensive care services, which are already working at high capacity levels.

“While the early results of this research show benefits to babies born with low blood sugars, it is clear there is more research to be done to implement this treatment.”

Source: BBC

Hip replacement death rate halved

Death rates following hip replacement surgery fell by half in England and Wales between 2003 and 2011, a study in The Lancet has found.

Although death within 90 days of surgery is rare, mortality decreased from 0.56% to 0.29% in an analysis of more than 400,000 patients.


The researchers said that fitter patients and better physiotherapy could be behind the decrease.

They added that simple treatment options would reduce the risk further.

Researchers from the universities of Bristol, Oxford, East Anglia and Exeter used data from the UK’s joint-replacement database, the National Joint Registry, to look at death rates following this type of surgery.

In their study they found that 1,743 patients died within 90 days of surgery during the eight years.

In 2004, 24,723 patients had hip replacement surgery and 139 of those died within 90 days.

While in 2011, there were 60,727 hip replacement operations carried out and 164 patient deaths.

Quick fix

The reason for the fall in death rates could be down to a number of factors.

The researchers identified the use of a spinal anaesthetic as likely to lead to fewer complications. Specific treatments to stop blood clots after surgery were also linked to a lower risk of death.

We need to concentrate efforts on reducing the risk of death in high risk groups such as those with severe liver disease.”

Prof Ashley BlomUniversity of Bristol

But people are also living longer and patients are recovering more quickly after surgery as a result of better post-operative care. For example, patients are encouraged to get up and start walking around the day after surgery.

The study said: “More recent generations of old people… are generally fitter and less frail than old people at the start of the study.

“Likewise, other aspects of surgery and anaesthesia have improved sufficiently to account for the change in mortality rates.”

The research team noticed that people with certain medical conditions were at a much higher risk of dying following surgery – particularly those with severe liver disease, those who had had a heart attack and those with diabetes and renal disease.

Those patients who died were most likely to be elderly men, they said.


But there were also some unexpected findings. Overweight people (with a body mass index of 25-30) appeared to have a lower risk of death after hip surgery than those patients with a “normal” BMI of 20-25.

Ashley Blom, professor of orthopaedic surgery at the University of Bristol, said: “The finding that overweight people have a lower risk of death is surprising, but has been confirmed by other recent studies, and challenges some of our preconceptions.

“We need to concentrate efforts on reducing the risk of death in high risk groups such as those with severe liver disease.”

But he said that the “dramatic” overall fall in death rates was “extremely good news”.

“It is also very exciting that we can further reduce the risk of post-operative death by adopting relatively simple measures,” Prof Blom said.

A spokesperson from Arthritis Research UK, welcomed the findings.

“This is great news for people in the UK who have osteoarthritis and require hip replacement surgery.

“Although not everyone who has arthritis will need hip replacement surgery, for many people, it’s their only hope to reduce the pain, disability and stiffness associated with the disease.

“There are however always risks associated in having major surgery such as hip replacement surgery, so we advise people to discuss these risks with their surgeon before they decide to have a hip replacement.”

Source: BBC


‘Bottled mucus’ may help gut disease.

Bottled mucus may one day play a role in some gut diseases, according to US researchers.

A study of the slimy lining of the bowels, published in the journal Science, showed mucus had a role in calming the immune system.


The team at Mount Sinai Hospital, in New York, believe it may be useful in diseases in which inflammation runs rampant in the intestines.

The human body naturally produces around a litre of mucus every day.

Researchers at the hospital and Mount Sinai School of Medicine were investigating why the lining of the bowel does not react to the trillions of bacteria which call the human intestines home. Elsewhere in the body, the immune system would launch a brutal attack against such invaders.

The team investigated the interaction between the mucus produced by the intestines and the immune system.

They showed that a mucus was not only acting as barrier between bacteria and immune system, but a component of the mucus was also calming the immune response. Sugars, or glycans, stuck to the a mucus protein called MUC2 were having the effect.

Lead researcher Dr Andrea Cerutti told the BBC: “We were able to show its ability to dampen the immune reaction in a specific type of immune cell, a dendritic cell, which orchestrates the immune response.

“But these are just initial studies; we know very, very little about mucus.”

Mucus treatments?

One area the team think mucus could help in is some bowel problems.

Crohn‘s disease, inflammatory bowel disease and ulcerative colitis are all poorly understood diseases, but do have inflammation, a part of the immune response, as a common feature.

Dr Cerutti said mucus was often disrupted in these patients and suggested that it may be possible to use mucus as a treatment.

One vision is to artificially synthesise mucus, although this is not currently possible, or a drug which can stimulate the same effect in the lining of the gut.

Whether such approaches to boost the mucus layer of the guts would help patients with bowel disorders is still unknown.

Mucus is not unique to the digestive system. It lines the lungs and streams out of the nose during a cold.

There is speculation that it could be producing similar immune-calming effects in the respiratory system and may be playing a role in allergies and asthma.

Dr Cerutti said even cancer may be affected by mucus: “Several aggressive tumours, such as colon, ovarian, and breast cancers produce mucus, including MUC2.

“Mucus produced by malignant cells may prevent protective immune responses against the malignant cells.”

Prof Jon Rhodes, from the department of gastroenterology at the University of Liverpool, said: “There’s a massive amount of work in this intriguing paper and it’s fascinating to read.

“To extrapolate this to just swallowing mucus would be hopelessly naive, but what might actually be interesting to speculate is that when the nature of the glycans are better understood it could lead to a very exciting and new type of therapeutic”

Source: BBC

All children offered flu nasal spray

  • Flu is a respiratory illness linked to infection by the influenza virus.
  • Symptoms usually include headache, fever, cough, sore throat, aching muscles and joints.
  • Influenza occurs most often in winter and usually peaks between December and March.
  • The virus was first identified in 1933.
  • There are two main types that cause infection: influenza A and influenza B
  • New strains of the virus are constantly emerging, which is why the flu vaccine should be given each year.

A flu vaccine nasal spray is being offered to every two and three-year-old in Scotland for the first time.

Previously, only children in “at risk” groups were offered the protection.

Scotland’s largest ever immunisation programme was launched by First Minister Alex Salmond, who received the vaccine in a surgery in Aberdeenshire.

He said that as an asthmatic, he gets the injection every year and urged other eligible Scots to get protected before the winter.

A fifth of the Scottish population will be offered a free flu vaccine, including people aged over 65 and those with conditions that put them at greater risk.

For the first time, all two and three-year-olds – about 120,000 children – will be offered the vaccine, as well as 100,000 primary school pupils in health board areas which are taking part in a pilot programme.

The programme will be rolled out to eventually see about one million children aged between two and 17 have the chance to be immunised towards the end of 2015.

The vaccine will take the form of a nasal spray rather than an injection.

Scotland’s senior medical officer said the spray, which is being phased in this autumn and rolled out over the next two years, was more effective in children than injections, as well as simpler to administer.

Speaking after receiving his own vaccine, Mr Salmond said it was better to be safe than sorry.

“As an asthmatic, I get my flu vaccination every year to make sure I’m protected and ready for the winter and I’m delighted to launch this national campaign,” he said.

“It is hugely successful and the existing programme has seen 2,000 fewer hospitalisations and 25,000 fewer GP consultations.

“For the first time this winter we are taking extra precautions to protect families by making sure children are also offered this vital vaccine.”

Senior medical officer Dr Nicola Steedman said every year she sees examples of how devastating flu can be.


She added: “For those with existing health conditions such as asthma, diabetes, heart or liver problems, flu can result in serious complications.

“Furthermore, those who are pregnant or over 65 are also at increased risk of flu and its complications and should be vaccinated to help protect against flu, even if they currently feel healthy and fit.


“Flu can also be very serious for children, particularly the youngest ones who have little or no immunity to the infection, which is why we are rolling out the new childhood flu immunisation programme.”

All two and three-year-olds in England and Wales will be also offered the vaccine this winter. In Wales, children aged 11 to 12 will also be eligible, while children aged between two and 10 in certain areas of England will be offered protection.

Source: BBC

Computer made from tiny carbon tubes.

The first computer built entirely with carbon nanotubes has been unveiled, opening the door to a new generation of digital devices.

“Cedric” is only a basic prototype but could be developed into a machine which is smaller, faster and more efficient than today’s silicon models.

Nanotubes have long been touted as the heir to silicon’s throne, but building a working computer has proven awkward.


The breakthrough by Stanford University engineers is published in Nature.

Cedric is the most complex carbon-based electronic system yet realised.

So is it fast? Not at all. It might have been in 1955.

Cedric’s vital statistics

  • 1 bit processor
  • Speed: 1 kHz
  • 178 transistors
  • 10-200 nanotubes per transistor
  • 2 billion carbon atoms
  • Turing complete
  • Multitasking
  • 100 microns – width of human hair
  • 10 microns – water droplet
  • 8 microns – transistors in Cedric
  • 625 nanometres (nm) – wavelength of red light
  • 20-450 nm – single viruses
  • 22 nm latest silicon chips
  • 9 nm – smallest carbon nanotube chip
  • 6 nm – cell membrane
  • 1 nm – single carbon nanotube
  • _70097572_handholdingcntwafer

How small is a carbon computer chip?

The computer operates on just one bit of information, and can only count to 32.

“In human terms, Cedric can count on his hands and sort the alphabet. But he is, in the full sense of the word, a computer,” says co-author Max Shulaker.

“There is no limit to the tasks it can perform, given enough memory”.

In computing parlance, Cedric is “Turing complete”. In principle, it could be used to solve any computational problem.

It runs a basic operating system which allows it to swap back and forth between two tasks – for instance, counting and sorting numbers.

And unlike previous carbon-based computers, Cedric gets the answer right every time.



“People have been talking about a new era of carbon nanotube electronics, but there have been few demonstrations. Here is the proof,” said Prof Subhasish Mitra, lead author on the study.

The Stanford team hope their achievement will galvanise efforts to find a commercial successor to silicon chips, which could soon encounter their physical limits.

Carbon nanotubes (CNTs) are hollow cylinders composed of a single sheet of carbon atoms.

They have exceptional properties which make them ideal as a semiconductor material for building transistors, the on-off switches at the heart of electronics.

For starters, CNTs are so thin – thousands could fit side-by-side in a human hair – that it takes very little energy to switch them off.

“Think of it as stepping on a garden hose. The thinner the pipe, the easier it is to shut off the flow,” said HS Philip Wong, co-author on the study.

Continue reading the main story

How small is a carbon computer chip?

  • 100 microns – width of human hair
  • 10 microns – water droplet
  • 8 microns – transistors in Cedric
  • 625 nanometres (nm) – wavelength of red light
  • 20-450 nm – single viruses
  • 22 nm latest silicon chips
  • 9 nm – smallest carbon nanotube chip
  • 6 nm – cell membrane
  • 1 nm – single carbon nanotube

But while single-nanotube transistors have been around for 15 years, no-one had ever put the jigsaw pieces together to make a useful computing device.

So how did the Stanford team succeed where others failed? By overcoming two common bugbears which have bedevilled carbon computing.

First, CNTs do not grow in neat, parallel lines. “When you try and line them up on a wafer, you get a bowl of noodles,” says Mitra.

The Stanford team built chips with CNTs which are 99.5% aligned – and designed a clever algorithm to bypass the remaining 0.5% which are askew.

They also eliminated a second type of imperfection – “metallic” CNTs – a small fraction of which always conduct electricity, instead of acting like semiconductors that can be switched off.

To expunge these rogue elements, the team switched off all the “good” CNTs, then pumped the remaining “bad” ones full of electricity – until they vaporised. The result is a functioning circuit.

The Stanford team call their two-pronged technique “imperfection-immune design”. Its greatest trick? You don’t even have to know where the imperfections lie – you just “zap” the whole thing.

“These are initial necessary steps in taking carbon nanotubes from the chemistry lab to a real environment,” said Supratik Guha, director of physical sciences for IBM’s Thomas J Watson Research Center.

But hang on – what if, say, Intel, or another chip company, called up and said “I want a billion of these”. Could Cedric be scaled up and factory-produced?

In principle, yes: “There is no roadblock”, says Franz Kreupl, of the Technical University of Munich in Germany.

“If research efforts are focused towards a scaled-up (64-bit) and scaled-down (20-nanometre transistor) version of this computer, we might soon be able to type on one.”

Shrinking the transistors is the next challenge for the Stanford team. At a width of eight microns (8,000 nanometres) they are much fatter than today’s most advanced silicon chips.

But while it may take a few years to achieve this gold standard, it is now only a matter of time – there is no technological barrier, says Shulaker.

“In terms of size, IBM has already demonstrated a nine-nanometre CNT transistor.

“And as for manufacturing, our design is compatible with current industry processes. We used the same tools as Intel, Samsung or whoever.

“So the billions of dollars invested into silicon has not been wasted, and can be applied for CNTs.”

For 40 years we have been predicting the end of silicon. Perhaps that end is now in sight.

Source: BBC

Satellite measures ‘quake island’.

The “quake island” that rose from the sea off Pakistan this week is pictured clearly in a new satellite image.

It was acquired by the French Pleiades high-resolution Earth-observing system, and has enabled scientists to map the muddy mound’s precise dimensions.


It is almost circular – 175.7m on the long axis and 160.0m on the short axis, giving a total area of 22,726 sq m.

The island, sited near the town of Gwadar, came up after the 7.7-magnitude tremor in the region.

Scientists say the intense shaking likely disturbed previously stable sediments and gas at the sea floor, which then oozed to the surface rather like a mud volcano.

The feature is not expected to persist. The ocean will erode the soft sediments, like it has with similar quake islands in the past.

The Gwadar mound is reported to be the fourth in the region since 1945, and the third during the last 15 years.


Pleiades is primarily a French national space project. It comprises two satellites that can resolve features on the ground as small as 50cm across.

The pair were built by Astrium, Europe’s largest space company; the imaging instrument was supplied by Thales Alenia Space (France).

Pleiades has both a civilian and a military role, and a number of European countries (Austria, Belgium, Spain and Sweden) have part-funded the project to get access to the pictures.

UC Davis researchers find how viral infection disrupts neural development in offspring, increasing risk of autism.

Activating a mother’s immune system during her pregnancy disrupts the development of neural cells in the brain of her offspring and damages the cells’ ability to transmit signals and communicate with one another, researchers with the UC Davis Center for Neuroscience and Department of Neurology have found. They said the finding suggests how maternal viral infection might increase the risk of having a child with autism spectrum disorder or schizophrenia.

The research, “MHCI Requires MEF2 Transcription Factors to Negatively Regulate Synapse Density during Development and in Disease,” is published in the Journal of Neuroscience.


The study’s senior author is Kimberley McAllister, professor in the Center for Neuroscience with appointments in the departments of Neurology and Neurobiology, Physiology and Behavior, and a researcher with the UC Davis MIND Institute.

“This is the first evidence that neurons in the developing brain of newborn offspring are altered by maternal immune activation,” McAllister said. “Until now, very little has been known about how maternal immune activation leads to autism spectrum disorder and schizophrenia-like pathophysiology and behaviors in the offspring.”

The study was conducted in mice and rats and compared the brains of the offspring of rodents whose immune systems had been activated and those of animals whose immune systems had not been activated. The pups of animals that were exposed to viral infection had much higher brain levels of immune molecules known as the major histocompatibility complex I (MHCI) molecules.

“This is the first evidence that MHCI levels on the surface of young cortical neurons in offspring are altered by maternal immune activation,” McAllister said.

The researchers found that the high MHCI levels impaired the ability of the neurons from the newborn mice’s brains to form synapses, the tiny gaps separating brain cells through which signals are transmitted. Earlier research has suggested that ASD and schizophrenia may be caused by changes in the development of connections in the brain, especially the cerebral cortex.

The researchers experimentally reduced MHCI to normal levels in neurons from offspring following maternal immune activation.

“Remarkably, synapse density returned to normal levels in those neurons,” McAllister said.

“These results indicate that maternal immune activation does indeed alter connectivity during prenatal development, causing a profound deficit in the ability of cortical neurons to form synapses that is caused by changes in levels of MHCI on the neurons,” she said.

MHCI did not work alone to limit the development of synapses. In a series of experiments, the UC Davis researchers determined that MHCI interacted with calcineurin and myocyte enhancer factor-2 (Mef2), a protein that is a critical determinant of neuronal specialization.

MHCI, calcineurin and Mef2 form a biological signaling pathway that had not been previously identified. McAllister’s team showed that in the offspring of the maternal immune activation mothers, this novel signaling pathway was much more active than it was in the offspring of non-MIA animals.

“This finding provides a potential mechanism linking maternal immune activation to disease-linked behaviors,” McAllister said.

It also is a mechanism that may help McAllister and other scientists to develop diagnostic tests and eventually therapies to improve the lives of individuals with these neurodevelopmental disorders.


As dengue is a deadly disease with more than 90% mortality in untreated cases, no established treatment so far till date.

It’s just symptomatic, iv fluids, anti pyretic and platelet transfusion.

As an ardent fan of Ayurveda and also a medical doctor i had seen more than 500 cases of dengue.

This Ayurveda so called cure is just a supplement therapy, not a 100% cure.

Readers are advised to use in with the standard treatment modality.

Pawpaw  (Papaya) Leaf Juice Is A Natural Cure For Dengue Fever

Two (2) pieces of raw Pawpaw (Papaya) leaves. Clean the leaves and pound and squeeze with a filter cloth. You will only get one tablespoon of juice per leaf. So, take two (2) tablespoons of Pawpaw (Papaya) leaf juice once a day. Do not boil, or cook, or rinse the leaves with hot water, as it will lose its strength. Use only the leafy part of the Pawpaw (Papaya) plant, and not the stem or sap. The juice is very bitter, and you have to swallow it. But it works.
Simple and Effective – blend the leaves, squeeze the juice, drink immediately.
Case Studies:
1. Male student was in a critical condition in the intensive care unit, when his blood platelet count dropped to 15, after a blood transfusion of 15-litres. The boy’s father was so worried that he sought a friend’s recommendation, and his son was saved. He gave his son the raw juice of the Pawpaw (Papaya) leaves. From a platelet count of 45 (after a blood transfusion of 20-litres), and after drinking the raw Pawpaw (Papaya) leaf juice, his platelet count jumped instantly to 135. Even the doctors and nurses were surprised. After two days in hospital, the boy was discharged.
2. Adult female had a very serious case of Dengue Fever, her platelet count had dropped to 28,000 after 3 days in hospital, and water had started to fill up her lungs, causing difficulty with breathing. She was only 32 years old. Her doctor said there was no cure for Dengue Fever, and she’d just have to wait for her body’s immune system to build up resistance against the Dengue Fever, and fight its own battle. She’d already had two blood transfusions, and her platelet count continued to drop since the first day she was admitted to hospital. Fortunately, her mother-in-law heard that Pawpaw (Papaya) Juice would help to reduce the fever. She got some leaves, pounded them, and squeezed the juice out for her. The next day, her platelet count started to increase, and her fever subsided. The Pawpaw (Papaya) Juice was fed to her, and she recovered after three days. Amazing, but true.
3. It’s believed that the body is overheated when suffering from Dengue Fever, and that Pawpaw (Papaya) Juice has a cooling effect. Thus, it helps to reduce the level of heat in the patient’s body, and the fever then goes away.
4. Pawpaw (Papaya) Juice has also been proven to have beneficial effects on sore throats, or when suffering from heat exhaustion (or overheating).

Feel free to write

Email id: /

Please share your views.

Honest comments and suggestions are always welcome.


Water glides freely across ‘nanodrapes’ made from the world’s thinnest material.

Engineering researchers at Rensselaer Polytechnic Institute have developed a new drape made from graphene—the thinnest material known to science—which can enhance the water-resistant properties of materials with rough surfaces.

These “nanodrapes” are less than a nanometer thick, chemically inert, and provide a layer of protection without changing the properties of the underlying material. The team of researchers, led by Rensselaer Professor Nikhil Koratkar, demonstrated how droplets of water encounter significantly less friction when moving across a surface covered with a nanodrape.

This innovation holds the potential to benefit lab-on-chip devices, high-throughput assays, self-cleaning surfaces, and many other applications requiring the motion of liquid drops onsolid surfaces.

“Graphene nanodrapes are the thinnest, most sheer drapes we can imagine. Other than providing a barrier against water, these drapes are optically transparent and cause minimal changes to the topology of the underlying surface,” said Koratkar, the John A. Clark and Edward T. Crossan Professor of Engineering at Rensselaer. “We found this ultrasheer drape prevents the penetration of water into textured surfaces, which has interesting and potentially important technological implications for many applications in micro- and nanofluidics.”

Drops of water can get easily stuck or “pinned” to a material with a nanotextured rough surface. When the droplet falls onto the material, the energy from the fall pushes out or displaces the tiny amounts of air trapped in the textured surface. Once in this pinned state, it is difficult to unpin the droplet and move it around the surface.

Covering the surface with an impermeable graphene drape, however, prevents a droplet from getting pinned to the surface. The nanodrape creates a barrier that prevents the water drop from penetrating into and displacing the air from the textured surface. Instead, the droplet sits on top of the drape, with reduced friction between them, which in turn makes it easier to move the droplet around on the surface, Koratkar said. While helping to minimize this friction, the ultrasheer nanodrape causes minimal disruption to the underlying surface.

The square nanodrapes measure several inches in length, and once applied to a surface are only detectable with a powerful microscope. Koratkar and the research team dropped small amounts of water on a surface of copper nanorods, and the same surface covered with a nanodrape. Water dropped on the bare surface spread out to form large flat drops indicative of a hydrophilic surface, while water dropped on nanodraped surfaces formed a much rounder or spherical drop indicative of a water-repellant or hydrophobic surface. The researchers also used high-speed cameras to observe and measure the shape of the drops as they impacted the surface, spread out, contracted, and finally settled. Once settled, the wettability of the surface was characterized by measuring the angle at which the liquid drop contacted the solid surface.

Koratkar said the water-resistant properties are apparent after the application of a single nanodrape, but the properties are enhanced with the addition of a few additional layers. Nanometer-size cracks and wrinkles likely form in the first layer as it is applied and settles onto the surface. The second and subsequent layers likely suffer from fewer defects, and help to cover up defects on the first layer.

Koratkar and his research team create the nanodrapes by growing graphene—a single layer of carbon atoms arranged like a nanoscale chicken-wire fence—on top of a copper substrate. They then coat the graphene with a polymer film, and use weak acids to remove or etch away the copper, which leaves the polymer layer with the graphene film underneath floating on the top of the liquid acids. The polymer layer with graphene sheet is then transferred to a surface, and the polymer layer is gently washed away using acetone. What remains is a single-carbon-atom thick, ultra-sheer, impermeable graphene drape.

This study is the latest from Koratkar, whose research is positioned at the intersections of nanotechnology, energy, and sustainability. His work has focused on the synthesis, characterization, and application of nanoscale material systems, including graphene. His research group uses different techniques to investigate ways of incorporating these materials into various composites, coatings, and device applications.

Results of the study were published earlier this year by the journal ACS Nano in the paper “Graphene Drape Minimizes the Pinning and Hysteresis of Water Drops on Nanotextured Rough Surfaces.”