Author Archives: Srinivas Chakravarty

World Thinnest Micro Lens Discovered, to Revolutionize Nanotech Applications

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Australian researchers have created the world’s thinnest lens, thousand times thinner than a human hair, which will revolutionize the nanotechnology frontiners into new smartphones, medical devices and miniature cameras.

Led by Yuerui Larry Lu from ANU Research School of Engineering, they discovered the potential of the molybdenum disulphide crystal which fits in the requirement to produce future lenses for visual devices.

“This type of material is the perfect candidate for future flexible displays,” said Dr Lu, leader of Nano-Electro-Mechanical System (NEMS) Laboratory in the ANU Research School of Engineering.

“We will also be able to use arrays of micro lenses to mimic the compound eyes of insects.”

The 6.3-nanometre lens outshines previous ultra-thin flat lenses, made from 50-nanometre thick gold nano-bar arrays, known as a metamaterial.

Molybdenum disulphide survives at high temperatures, is a lubricant, a good semiconductor and can emit photons too with capability of manipulating the flow of light in atomic scale opens an exciting avenue towards unprecedented miniaturisation of optical components and the integration of advanced optical functionalities, he explained.

Yuerui Lu, who received his Ph.D. degree from Cornell University, the school of Electrical and Computer Engineering, in 2012, joined the Australian National University as research fellow and lecturer under the Future Engineering Research Leadership Fellowship.

In October 2015, he was promoted to Senior Lecturer at the ANU. His research interests include MEMS/NEMS sensors and actuators, nano-manufacturing technologies, renewable energy harvesting, biomedical novel devices, nano-materials, nano-electronics, etc.

Molybdenum disulphide, known as chalcogenide glasses with flexible electronic characteristics can eb made from high-technology components. The team has created lens from a crystal 6.3-nanometres thick – 9 atomic layers – which they had peeled off a larger piece of molybdenum disulphide with sticky tape before creating a 10-micron radius lens, using a focussed ion beam to shave off the layers atom by atom, until they had the dome shape of the lens.

The team discovered that single layers of molybdenum disulphide, 0.7 nanometres thick, had remarkable optical properties, appearing to a light beam to be 50 times thicker, at 38 nanometres. This property, known as optical path length, determines the phase of the light and governs interference and diffraction of light as it propagates.

Then Assistant Professor Zongfu Yu at the University of Wisconsin, Madison, developed a simulation and showed that light was bouncing back and forth many times inside the high refractive index crystal layers before passing through. Molybdenum disulphide crystal’s refractive index, the property that quantifies the strength of a material’s effect on light, has a high value of 5.5.

Molybdenum disulphide crystal can be compared to a diamond, whose high refractive index causes its sparkle, is only 2.4, and water’s refractive index is 1.3.

This study is published in the Nature serial journal Light: Science and Applications.

Researchers Reveal Mechanism that Impairs Blood Flow with Aging

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The Physiological Society’s Journal of Physiology recently published a study led by Erika Boerman, identifying an age-related cause of arterial dysfunction.

 

 

With the world’s elderly population expected to double by 2050, understanding cardiovascular disease, the No. 1 cause of death worldwide, is often highlighted and now University of Missouri researchers have identified an age-related cause of arterial dysfunction, a finding that could lead to future treatments.

“Aging affects everyone and causes changes throughout our bodies,” said Erika Boerman, a post-doctoral fellow in the Department of Medical Pharmacology and Physiology at the MU School of Medicine and lead author of the study. “We found that older arteries had a significantly lower number of sensory nerves in the tissues surrounding them and they were less sensitive to an important neurotransmitter responsible for dilation.”

Boerman’s study focused on mesenteric arteries ― a type of artery that supplies blood to the small intestines ― of mice that were 4 months and 24 months old. These ages correspond to humans in their early 20s and mid-60s, respectively. Without stimulation, the diameter of the blood vessels of both younger and older mice was approximately the same. However, when stimulated to induce dilation, differences between the age groups became apparent.

“The younger arteries dilated as expected,” Boerman said. “However, when we performed the same stimulation to the arteries of older mice, the vessels did not dilate. When we examined the presence of sensory nerves, we noted a 30 percent decrease in the amount surrounding the older arteries compared to the younger arteries.”

Additionally, the researchers found that even when purposefully exposing older mesenteric arteries to defined amounts of the neurotransmitter calcitonin gene-related peptide, or CGRP, the arteries’ ability to dilate was greatly reduced.

“Poor neurotransmitter function and a reduced presence of sensory nerves surrounding older vessels lead to age-related dysfunction of mesenteric arteries,” Boerman said. “The importance of this discovery is that if we can identify why this happens to mesenteric arteries, it may be possible to prevent the same thing from happening to other blood vessels throughout the body.”

More research is needed to understand why aging affects sensory nerve distribution and neurotransmitter performance. However, identifying this new mechanism of vascular dysfunction opens the door for future studies that could eventually lead to the treatment of health issues such as stroke and cardiovascular disease.

The study was published in The Physiological Society’s Journal of Physiology.

Crocodiles Set to Face Extinction, Says Australian Researcher

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An estuarine crocodile, also known as a “saltie”.

Many of the world’s 27 species of crocodylians will soon be either totally or locally extinct due to human population expansion and intensive land-use for agriculture depleting the water bodies, which provide succour to crocs, said a University of Queensland researcher.

Emeritus Professor Gordon Grigg of UQ says the fact that these reptiles had survived millions of years was no good owing to current rate of human expansion and encroachment of natural resources. “The current human population level and its magnitude and rate of resource consumption are unprecedented,” Professor Grigg said.

Only those crocs living in remote wetland habitats in which humans see no benefit may survive into the future, he said. Some crocodylians might have already become extinct if not for active conservation management undertaken in the second half of the 20th Century.

“For some species, the incentive for conserving them has been the commercial value of their hides, but that is dependent upon its use in high fashion garments and accessories, and that is a somewhat fragile foundation,” he said.

On flip side, the rising temperatures and sea levels may turn a more positive note for crocodylians, as it may create more habitat that will be suitable for any species to survive the human onslaught, he said wryly.

The largest living crocodiles, the estuarine or saltwater crocodile (Crocodylus porosus), are found in Northern Australia and can grow to six metres and weigh more than 900 kilograms.

Professor Grigg said estuarine crocodiles, also known as Indo-Pacific crocodiles or “salties”, were one of the luckier species because human populations across Australia’s north were unlikely to increase significantly in the next few decades.  They might be among the survivors.

Professor Grigg and illustrator and biologist David Kirshner, in their recent book, Biology and Evolution of Crocodylians, reviewed the biology of the crocodiles, alligators, caimans and gharials, and also discusses the great diversity of their gigantic extinct ancestors, some of which were probably warm-blooded.

Missing Mobile Phone? Don’t Let it Take Over as Phobia!

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Apple’s iPhone 6

Call it missing mobile phone phobia or nomophobia or just another day of anxiety when you miss your device at home or office.

Scientists from Iowa State University have identified four dimensions of the phobia after a survey conducted on participants, who responded on a scale of one (strongly disagree) to seven (strongly agree).

More to do with the fear of losing connectedness with friends and family or not being able to access information, the fear of remaining incommunicado even for few hours haunts majority of them.

Initially the researchers interviewed nine students and based on their responses, developed a questionnaire which was given to 301 students.

Research student Caglar Yildirim at the Iowa State University (ISU) and Ana-Paula Correia, an associate professor in ISU’s School of Education finally came out with a set of four dimensions to detect the most-prevalent modern-day phenomenon that is often taking the shape of phobia.

Based on the score, the researchers said the higher scores corresponded to greater nomophobia severity, and vice versa. The team findings have been published in the journal Computers in Human Behavior.

Here are the sample questions in the questionnaire:

— “I would feel uncomfortable without constant access to information through my smartphone”

— “I would be annoyed if I could not look information up on my smartphone when I wanted to do so”.

“Being unable to get the news on my smartphone would make me nervous” or
“I would be annoyed if I could not use my smartphone and/or its capabilities when I wanted to do so”.

— “Running out of battery in my smartphone would scare me”

— “If I were to run out of credits or hit my monthly data limit, I would panic” and
“If I did not have a data signal or could not connect to Wi-Fi, then I would constantly check to see if I had a signal or could find a Wi-Fi network”.

Here are some typical answers from the participants:

— “If I could not use my smartphone, I would be afraid of getting stranded somewhere”.

— “If I could not check my smartphone for a while, I would feel a desire to check it”.

To a question as to how they would react if they did not have their smartphone with them, they responded with statements like:

— “I would feel anxious because I could not instantly communicate with my family and/or friends”

— “I would feel nervous because I would not be able to receive text messages and calls.”

Life Expectancy: Indian women live longer than men

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Life expectancy has escalated to a great extent since 1990 as people even in poor nations are living longer than ever, though many of them struggling with sickness and age-old ailments, finds a new study.

In India, between 1990 and 2013, life expectancy for men and women has elevated by 6.9 years and 10.3 years, respectively.

Photo Credit: Pedro Ribeiro Simões

This new study was conducted in 188 countries by an international research team working on a project called “Global Burden of Disease” and headed by Institute for Health Metrics and Evaluation (IHME) at the University of Washington.

Owing to the deterioration of mortality and illness rates due to HIV/AIDS and malaria in the last ten years, health has enhanced to a great deal across the globe. Apart from this, meeting contagious, maternal, newborn and nutritive conditions, effectively has also added to the enhancement.

Nevertheless, healthy life expectancy (HALE) at birth hasn’t seen much improvement, thus; making those who live longer live sicker.

Theo Vos, the professor of IHME as well as who lead the study said albeit health has seen a global advancement it’s time that “more effective ways” to treat and combat disorders and diseases are discovered.

The study discovered that global life expectancy and healthy life expectancy for both genders escalated by 6.2 years and 5.4 years, respectively. However, in comparison to the life expectancy that increased from 65.3 in 1990 to 71.5 in 2013, healthy life expectancy didn’t see a drastic leap with 56.9 in 1990 to 62.3 in 2013.

Majority of the evaluated nations showed “significant and positive” healthy life expectancy changes. However, Belize, Botswana and Syria didn’t show drastic changes in HALE in 2013 as compared to 1990 with the first two nations, showing regression of 2 and 1.3 years, respectively.

In other cases, countries like Paraguay, Belarus and South Africa saw a deterioration in healthy life expectancy. For instance, places like Swaziland and Lesotho in Africa and South Africa, respectively, saw healthy life expectancy drop in individuals born in 2013 as compared to them who were born 20 years before.

People of Cambodia and Nicaragua showed gripping escalation between 1990 and 2013 with 13.9 and 14.7 years, respectively.

Nonetheless, Ethiopia was pin-pointed as one of the nations that have been giving massive efforts to make sure that their country people live both healthier and longer. For instance, in 1990, the healthy life expectancy of an Ethiopian was 40.8 years, but by 2013 with 13.5 years leap, it saw over a two-fold increase to 54.3 years.

Christopher Murray, who is the IHME director said albeit “income and education” play important roles in ensuring proper health, it doesn’t “tell the full story,” adding that weighing both healthy life expectancy and health loss on each sides at country level will facilitate “guide policies” in ensuring longer and healthier lives in every nook and cranny of the world.

Italy, Spain, Norway, Switzerland and Israel showed the lowest rates of health loss. With 42 years, in 2013, Lesotho recorded the lowest healthy life expectancy whereas with 73.4 years, Japan recorded the highest healthy life expectancy.

The findings have been published in the August 27 issue of the journal “The Lancet”.

According to the World Health Organization (WHO), Europe showed stagnation in showing better life expectancy during the 1990s, but after 1990 when life expectancy increased by 6 years around the world, Europe also saw some increase.

On the other hand, African nations have been showing a drop in life expectancy due to being plagued by HIV/AIDS, but now with the accessibility of antiretroviral therapy, the rates have seen an escalation. For instance, in 2000, standard life expectancy at birth was 50 years, but it saw an 8 year leap in 2013.

WHO further informed that high-income nations showed greater life expectancy at 60 years of age with expectation of the individual, living another 23 years in comparison to low-income and lower-middle income nations, which showed 17 more years of life expectancy.

India Ready with ‘Comprehensive’ Plan on INDCs Ahead of Paris Meet: Javadekar

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The Minister of State for Environment, Forest and Climate Change (Independent Charge), Shri Prakash Javadekar addressing a Press Conference on Intended Nationally Determined Contributions (INDCs), in New Delhi on August 24, 2015. The Secretary, Environment, Forests and Climate Change, Shri Ashok Lavasa and the Director General (M&C), Press Information Bureau, Shri A.P. Frank Noronha are also seen. (PIB Photo).

India’s environment minister Prakash Javadekar has reiterated India’s stand on compliance with the Climate Change agreements in the past and to forge ahead with its comprehensive plan at the Paris Summit to be held in December this year.

The minsiter said India is finalizing its draft proposal before the crucial UN climate change conference in Paris and unlike most other countries whose ‘Intended Nationally Determined Contributions’ (INDCs) reflect only mitigation measures, India will have two different templates — one for adaptation and the other for mitigation apart from technology and capacity build up, Javadekar said.

Wrapping up an 8-month effort, the minister said “We are at an advanced stage of preparing our INDC… We have been engaged in this exercise and widest consultations have taken place with all ministries, state governments, research institutes, industry, think tanks and many organisations.”

Javadekar said all elements will be part of India’s INDCs, including efforts for mitigation, adaptation, finance, technology and capacity building, he said preparing for the final draft. He said India’s INDCs reflect the mandate of United Nations Framework Convention on Climate Change (UNFCCC).

However, India is still a latecomer in terms of submission of its INDCs as the US, China and the European Union countries have already submitted their INDCs. Some of the projects undertaken by the ministry of forests and environment will figure in the INDCs, it is learnt.

But India has made it evident in all global gatherings that “Developed world would now have to walk the talk and will have to provide green climate fund to the developing world.”

Being a developing nation, India has maintained its “Common but Differentiated Responsibility” approach to global climate change and sought the developed world to pay the developing world or poorer nations like India and defer the carbon tax model for some more time.

The UN has been insisting on a “realistic” trajectory to mobilize $100 billion per year by 2020 that was pledged by developed countries in 2009 – with resources above and beyond official development assistance (ODA).

The UN Green Climate Fund has remained a lukewarm effort without funds.

Imagine World Map Without Humans, Here It Is!

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An interesting study by Arhus University in Spain has come out with a world map sans humans and how it would have shaped the animal world on Earth, if man had not appeared about 100,000 years ago.

 

The fact that the greatest diversity of large mammals is found in Africa reflects past human activities – and not climatic or other environmental constraints. This is determined in a new study, which presents what the world map of mammals would look like if modern man (Homo sapiens) had never existed.

In a world without humans, most of northern Europe would probably now be home to not only wolves, Eurasian elk (moose) and bears, but also animals such as elephants and rhinoceroses.

This is demonstrated in a new study conducted by researchers from Aarhus University, Denmark. In a previous analysis, they have shown that the mass extinction of large mammals during the Last Ice Age and in subsequent millennia (the late-Quaternary megafauna extinction) is largely explainable from the expansion of modern man (Homo sapiens) across the world.

In this follow-up study, they investigate what the natural worldwide diversity patterns of mammals would be like in the absence of past and present human impacts, based on estimates of the natural distribution of each species according to its ecology, biogeography and the current natural environmental template. They provide the first estimate of how the mammal diversity world map would have appeared without the impact of modern man.

“Northern Europe is far from the only place in which humans have reduced the diversity of mammals – it’s a worldwide phenomenon. And, in most places, there’s a very large deficit in mammal diversity relative to what it would naturally have been”, says Professor Jens-Christian Svenning, Department of Bioscience, Aarhus University, who is one of the researchers behind the study.

Antarctic Detector Confirms Cosmic Neutrino Sighting

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IMAGE: A A HIGH-ENERGY NEUTRINO EVENT OF THE NORTHERN SKY SUPERIMPOSED ON A VIEW OF THE ICECUBE LAB AT THE SOUTH POLE.(CREDIT: ICECUBE COLLABORATION)

Researchers using the IceCube Neutrino Observatory have sorted through the billions of subatomic particles that zip through its frozen cubic-kilometer-sized detector each year to gather powerful new evidence in support of 2013 observations confirming the existence of cosmic neutrinos.

In the new study, the detection of 21 ultra high-energy muons — secondary particles created on the very rare occasions when neutrinos interact with other particles –provides independent confirmation of astrophysical neutrinos from our galaxy as well as cosmic neutrinos from sources outside the Milky Way.

The observations were reported in the journalPhysical Review Letters by the IceCube Collaboration, which called the data an “unequivocal signal” for astrophysical neutrinos, ultra high-energy particles that have traversed space unimpeded by stars, planets, galaxies, magnetic fields or clouds of interstellar dust — phenomena that, at very high energies, significantly attenuate more mundane particles like photons.

Because they have almost no mass and no electric charge, neutrinos can be very hard to detect and are only observed indirectly when they collide with other particles to create muons, telltale secondary particles.

The IceCube Collaboration, a large international consortium headquartered at the University of Wisconsin-Madison, has taken on the huge challenge of sifting through a mass of observations to identify perhaps a few dozen of the highest-energy neutrinos that have traveled from sources in the Milky Way and beyond our galaxy.

 

“Looking for muon neutrinos reaching the detector through the Earth is the way IceCube was supposed to do neutrino astronomy and it has delivered,” explains Francis Halzen, a UW-Madison professor of physics and the principal investigator of IceCube. “This is as close to independent confirmation as one can get with a unique instrument.”

Between May 2010 and May 2012, IceCube recorded more than 35,000 neutrinos. However, only about 20 of those neutrino events were clocked at energy levels indicative of astrophysical or cosmic sources.

 

But while the new observations confirm the existence of astrophysical neutrinos and the means to detect them using the IceCube Observatory, actual point sources of high-energy neutrinos remain to be identified.

Albrecht Karle, a UW-Madison professor of physics and a senior author of the Physical Review Letters report, notes that while the neutrino-induced tracks recorded by the IceCube detector have a good pointing resolution, within less than a degree, the IceCube team has not observed a significant number of neutrinos emanating from any single source.

 

IceCube is based at the Wisconsin IceCube Particle Astrophysics Center (WIPAC) at UW-Madison. The observatory was built with major support from the National Science Foundation as well as support from partner funding agencies worldwide. More than 300 physicists and engineers from the United States, Germany, Sweden, Belgium, Switzerland, Japan, Canada, New Zealand, Australia, the United Kingdom, Korea and Denmark are involved in the project.