#New method to generate arbitrary optical pulses The technique which was developed by researchers from the University's Optoelectronics Research Centre (ORC) has potential applications in a number of fields that use pulsed lasers including telecommunications metrology sensing and material processing.
Any application that requires optical pulses typically needs waveforms of a specific repetition rate pulse duration and pulse shape.
It is often challenging to design and manufacture a laser with these parameters exactly as required.
Even when a suitable solution exists the size the complexity and ease of operation of the laser are further critical considerations.
The new method works on a fundamentally different principle to existing pulsed lasers. It relies upon the coherent combination of multiple semiconductor lasers each operating continuous-wave at different precisely defined frequencies (wavelengths.
Through the precise control of the amplitude and phase of each laser's output it is possible to produce complex pulsed optical waveforms with a huge degree of user flexibility.
The key to making the approach work is to phase-lock the semiconductor lasers to an optical frequency comb
which ensures the individual lasers have well-defined mutual coherence. David Wu lead author of the study
and winner of the 2014 Engineering and Physical sciences Research Council (EPSRC) ICT Pioneers award for this work said:
As our new technique is based on a different approach to that currently used it has several distinct features that are relevant in many applications.
First it is easily scalable--by combining a larger number of input lasers shorter or more complicated-shape pulses and/or more power can be obtained.
It can also generate pulses with a very low-level of noise (down to the quantum limit) and very high (greater than one THZ) repetition frequencies.
Finally it consists of miniature and low-cost semiconductor lasers that can be integrated all on the same chip making our pulse generator potentially very compact robust energetically efficient and low-cost.
Dr Radan Slavik who leads the research group added: We believe that this work is likely to be of direct interest to scientists working in virtually any field of optics where pulsed laser sources are used.
We also believe that the concept and phase-locking technology developed could be widely applicable with the broader optics/photonics community y
If hypoglycemia develops in these premature babies and persists for over an hour, it can affect brain development.
and stress would be too great. In a project funded by The swiss National Science Foundation (SNSF),
Empa and the University Hospital Zurich thus teamed up to develop the sensor"Glucolight,""which gages the blood sugar level through the skin,
Although skin sensors already exist, they have to be calibrated before use, which means that the skin's permeability value needs to be known.
In order to establish this, the blood sugar value has to be determined via a blood sample and the glucose concentration on the skin measured.
Based on these readings, the permeability can then be calculated and the sensor calibrated. A different method to previous sensors Glucolight spares the premature babies blood samples
and enables the blood sugar level to be monitored permanently thanks to the sensor's novel measuring technology,
which comprises several parts: A microdialysis measuring head, which was developed at the University Hospital Zurich,
with a"smart"membrane developed at Empa; light sources; a pump; and a microfluidics chip with a fluorometer,
also developed at the University Hospital Zurich. The smart Empa membrane contains special dye molecules, known as spiropyrans.
If UV LIGHT is beamed onto these spiropyran molecules, they alter their chemical structure and become charged (polar).
and pumped through the microfluidics chip, while enzymes are added to trigger a reaction. During the reaction, a fluorescence appears, which the fluorometer measures,
and the computer uses the reading to calculate the glucose concentration. The process is repeated then with UV LIGHT.
The computer then uses these two different readings to calculate the premature baby's blood sugar level.
and the first clinical studies are scheduled at the University Hospital Zurich for 2015. However it could be years before the use of Glucolight becomes standard.
Empa and the University Hospital Zurich are currently in negotiations with partners for the industrial production of the sensor.
For the future, the researchers also envisage the use of Glucolight in other fields, such as diabetes s
#Self-assembled nanotextures create antireflective surface on silicon solar cells Reducing the amount of sunlight that bounces off the surface of solar cells helps maximize the conversion of the sun's rays to electricity,
Now scientists at the U s. Department of energy's Brookhaven National Laboratory show that etching a nanoscale texture onto the silicon material itself creates an antireflective surface that works as well as state-of-the-art thin-film multilayer coatings.
has potential for streamlining silicon solar cell production and reducing manufacturing costs. The approach may find additional applications in reducing glare from windows, providing radar camouflage for military equipment,
and increasing the brightness of light-emitting diodes.""For antireflection applications, the idea is to prevent light
or radio waves from bouncing at interfaces between materials,"said physicist Charles Black, who led the research at Brookhaven Lab's Center for Functional Nanomaterials (CFN), a DOE Office of Science User Facility.
Preventing reflections requires controlling an abrupt change in"refractive index, "a property that affects how waves such as light propagate through a material.
This occurs at the interface where two materials with very different refractive indices meet, for example at the interface between air and silicon.
Adding a coating with an intermediate refractive index at the interface eases the transition between materials
and reduces the reflection, Black explained.""The issue with using such coatings for solar cells, "he said,
"is that we'd prefer to fully capture every color of the light spectrum within the device,
"We set out to recreate moth eye patterns in silicon at even smaller sizes using methods of nanotechnology,
The scientists started by coating the top surface of a silicon solar cell with a polymer material called a"block copolymer,
"which can be made to self-organize into an ordered surface pattern with dimensions measuring only tens of nanometers.
The self-assembled pattern served as a template for forming posts in the solar cell like those in the moth eye using a plasma of reactive gases-a technique commonly used in the manufacture of semiconductor electronic circuits.
The resulting surface nanotexture served to gradually change the refractive index to drastically cut down on reflection of many wavelengths of light simultaneously, regardless of the direction of light impinging on the solar cell."
Solar cells textured in this way outperform those coated with a single antireflective film by about 20 percent,
whether there are economic advantages to assembling silicon solar cells using our method, compared to other, established processes in the industry,
"We have all these experts around who can help you solve your problems.""Using a combination of computational modeling, electron microscopy,
"On a flat surface, this layer is so thin that its effect is explained minimal Matt Eisaman of Brookhaven's Sustainable energy Technologies Department and a professor at Stony Brook University."
"But on the nanopatterned surface, with the thin oxide layer surrounding all sides of the nanotexture,
including glass and plastic, for antiglare windows and coatings for solar panels. This research was supported by the DOE Office of Science e
#Connection between childhood adversity psychiatric disorders seen at cellular level Mitochondria convert molecules from food into energy that can be used by cells
Telomere shortening is also a measure of advanced cellular aging. Recent studies have examined the possible connection between mitochondria
and psychiatric disorders but the research is limited very and no prior work has examined the relationship of MITOCHONDRIAL DNA to psychosocial stress.
We are interested in these relationships because there is now clear evidence that stress exposure and psychiatric conditions are associated with inflammation
and health conditions like diabetes and heart disease. Identifying the changes that occur at a cellular level due to these psychosocial factors allows us to understand the causes of these poor health conditions
and possibly the overall aging process. said Audrey Tyrka MD Phd Director of the Laboratory for Clinical and Translational Neuroscience at Butler Hospital and Associate professor of Psychiatry and Human Behavior at Brown University.
Tyrka and fellow researchers recruited 299 healthy adults from the community for the study. Participants completed diagnostic interviews to assess psychiatric disorder diagnosis
and assess childhood adversities including parental loss and childhood abuse and neglect. Participants were categorized into four groups based upon the presence
or absence of childhood adversity and the presence or absence of lifetime depressive anxiety or substance use disorders.
Using standard techniques researchers extracted DNA from whole blood samples for each participant and quantified telomere length
These effects were seen in individuals with major depression depressive disorders and anxiety disorders as well as those with parental loss and childhood maltreatment.
These findings indicate that childhood stress and some psychiatric disorders are linked to important cellular changes that may represent advanced cellular aging.
Understanding this biology is necessary to move toward better treatment and prevention options for stress-related psychiatric and medical conditions
and may shed light on the aging process itself. said Dr. Tyrka also the director of research for Butler Hospital l
#Technique reveals age of planetary materials The key to understanding the geologic history of the Solar system is knowing the ages of planetary rocks.
and in field environments here On earth,"said lead author Dr. F. Scott Anderson.""Furthermore, in addition to obtaining dates,
#New cancer-fighting strategy would harden cells to prevent metastasis Existing cancer therapies are geared toward massacring tumor cells
This is a novel approach to cancer therapy that we believe could fight the disease with less potential for side effects
and drug resistance than many current drugs says Douglas Robinson Ph d. a professor of cell biology in the Institute for Basic Biomedical sciences at Johns hopkins university School of medicine.
We think the new screening system we devised will help identify drugs for many other diseases as well.
Since changes in cell shape figure into conditions from cancer to chronic obstructive pulmonary disease to degenerative nerve diseases compounds that affect cells shape could turn out to stall disease progress.
and began working on a screen for molecules that tweak cell shape. Most drug screens look for an effect on a specific biochemical pathway that has been linked to disease;
by contrast Surcel explains this screen is based on the end result for a whole cell--in this case the amoeba Dictyostelium
which closely resembles a number of mammalian cell types. After treating the cells with a molecule Robinson's team looked for out-of-the-ordinary numbers of cells with two or more nuclei.
A screen of thousands of molecules turned up 25 with the effect the team was looking for Further studies revealed that one of them 4-HAP affected myosin II a building block of the cell skeleton.
In collaboration with another Johns Hopkins lab led by Robert Anders M d. Ph d. an associate professor of pathology Robinson's group identified changes in the amount of myosin II in pancreatic cancer cells as they spread from the original
tumor into other areas of the body a crucial step in progression of the disease. The research team tested 4-HAP on lab-grown pancreatic cancer cells
The drug is already in use in some countries as a treatment for jaundice so if it shows success against pancreatic cancer it could potentially make it to market relatively quickly Robinson says.
#Scientists invent system to improve effectiveness of cancer surgery With the goal of making it easier for surgeons to detect malignant tissue during surgery
and hopefully reduce the rate of cancer recurrence, scientists have invented a new imaging system that causes tumors to ight upwhen a hand-held laser is directed at them. surgeon goal during cancer surgery is to remove the tumor,
as well as enough surrounding tissue to ensure that malignant cells are not left behind, said Aaron Mohs, Ph d,
. assistant professor of regenerative medicine at Wake Forest Baptist Medical center and a co-inventor of the system. ut how do they know when theye removed enough tissue?
Our goal is to provide better real-time information to guide the surgery. Published online ahead of print in IEEE Transactions on Biomedical engineering (TBME),
Mohs and co-authors report on their prototype system that combines a fluorescent dye that localizes in tumors with a real-time imaging system that allows the surgeon to simply view a screen to distinguish between normal tissue and the ightedmalignant tissue.
In both mice and companion dogs with tumors, the scientists found that the fluorescent dye accumulated at higher levels in tumors than in the surrounding tissue
and the system was able to detect a distinct boundary between normal and tumor tissue.
Canine tumors are known to be similar to human tumors in architecture and canines get the same types of tumors as humans.
The scientists are working to further develop the system so it can be evaluated in human patients.
Current technology allows cancer surgeons to scan tumors prior to surgery with magnetic resonance imaging and other systems.
However, to scan the tumor during surgery involves moving the patient from the operating table and into the machinery hich prolongs the surgery. eing able to quickly scan a tumor during surgery to visualize tumor tissue from non-tumor tissue is an unmet clinical need,
said Mohs. athology techniques that examine tumor tissue during surgery can take up to 20 minutes
and they focus on the tissue removed during surgery, not the tissue that remains in the body.
In TBME, the authors noted that the ideal system would find tumor boundaries with high sensitivity,
have minimal impact on operative time and surgical technique, present findings in an intuitive manner and avoid the use of ionizing radiation or a specialized imaging environment, such as MRI machines.
The system, invented by Mohs, Michael C. Mancini at Spectropath Inc, . and Shuming Nie with Emory University and Georgia Institute of technology, combines two types of imaging.
A surgeon-controlled laser can be directed at any area of interest. In addition an imaging system with three cameras sits above the surgical field.
The images recorded by both systems are processed to display a composite image. Using this system,
a surgeon would scan the tumor prior to surgery to determine its boundaries. The tumor would then be removed surgically
and the area would be scanned re to assess for any remaining malignant tissue. If diseased tissue is found,
it would be removed, and the process would be repeated until diseased tissue could no longer be detected. In the prototype system reported in TBME,
the scientists used indocyanine green dye as the source of fluorescence. They noted that future studies will focus on higher performance fluorescent dyes
and nanoparticles that can be targeted to specific tumors. Recently, Mohs was awarded a $1. 37 million research grant from the National Institute of Biomedical Imaging
and Bioengineering for a project to optimize the system and to test it in rodents.
Under the four-year project, Mohsteam will develop nanoparticles based on hyaluronic acid, a substance naturally present in the human body.
These nanoparticles will have the ability to entrap near infrared fluorescent dyes. The research will investigate invasive ductal carcinoma, the most common type of breast cancer.
Under the project, the researchers will focus on optimizing the loading of the dye, determining how fluorescence can be activated
and performing studies in rodents to evaluate safety and whether disease recurrence is reduced. Members of the research team
all from Wake Forest Baptist, are: Edward Levine, M d.,Surgical Sciences Oncology; Frank Marini, Ph d,
. and Graca Almeida Porada, M d.,Ph d.,Institute for Regenerative medicine; Ralph D'Agostino, Ph d.,Biostatistics; and King Li, M d.,Division of Radiologic Science.
Grant Number: 1r01eb019449-01) Co-authors on the TBME paper, in addition to the inventors, were James M. Provenzale, M d.,Duke university Medical center and Emory University;
and Corey F. Saba, D. V. M.,Karen K. Cornell, D. V. M.,Ph d, . and Elizabeth W. Howerth, D. V. M.,Ph d.,University of Georgia. Media Contacts:
Karen Richardson, krchrdsn@wakehealth. edu,(336) 716-4453) or Main Number (336) 716-4587. Wake Forest Baptist Medical center (www. wakehealth. edu) is recognized a nationally academic medical center in Winston-salem, N c,
. with an integrated enterprise including educational and research facilities, hospitals, clinics, diagnostic centers and other primary and specialty care facilities serving 24 counties in northwest North carolina and southwest
Virginia. Its divisions are Wake Forest Baptist Health, a regional clinical system with close to 175 locations, 900 physicians and 1, 000 acute care beds;
Wake Forest School of medicine, an established leader in medical education and research; and Wake Forest Innovations,
which promotes the commercialization of research discoveries and operates Wake Forest Innovation Quarter, an urban research and business park specializing in biotechnology, materials science and information technology.
Wake Forest Baptist clinical, research and educational programs are ranked annually among the best in the country by U s. News & World Report u
#New antibodies for cancer treatment A research team at Aarhus University i Denmark has developed ten new antibodies that can possibly be used in the battle against cancer.
They work by inhibiting the body's blood vessel formation close to the tumour which is thereby cut off from oxygen and nutrient supply.
Up to now the researchers have tested some of the antibodies on mice and in the laboratory they have succeeded in using them to stop the development of malignant tumours.
The antibodies we've found prevent a cancer tumour from growing. They appear to work perfectly in the laboratory
and this means of course that they've got incredibly interesting therapeutic potential that we'll investigate further.
However we're still quite early in the experimental stage says Associate professor Peter Kristensen. He is the main architect behind the new antibodies
but he stresses that the results are preliminary. The antibodies neutralise the effects of signal substances released by carcinoma cells to get blood vessels to replicate
thus cutting off the blood supply to the tumour. A cancer tumour deprived of oxygen and nutrients becomes dormant
and is made thereby harmless. If it receives a supply from the bloodstream however it grows
and spreads and the researchers appear to be able to prevent this deadly process. They are among the world's leading specialists in developing artificial antibodies for cancer treatment
and in recent years they have worked on compositions of genes for a collection of several billion new types of antibodies.
To date they have identified actually ten that appear to be able to impede the development of cancer.
A small number of therapeutic antibodies already exist some of which have the same effect as the antibodies developed by the Aarhus University researchers.
However the existing antibodies are extremely expensive to produce. The new antibodies are easier to extract
and they also appear to be more effective because they hit other--and possibly stronger--signal molecules from the cancer cells.
The demand for therapeutic antibodies for cancer treatment is steadily increasing. In 2013 alone worldwide sales amounted to more than DKK 340 billion.
The art of finding a needle in a haystackestablishing an extensive library of artificial antibodies is no major research achievement in itself.
The difficulty is singling out the few that work and this is something the Aarhus University researchers are good at.
We've got a large library of antibodies that can supplement the body's own fight against disease.
The major engineering challenge is identifying the ones that are relevant regarding the specific purpose. In this case we've found those that have an inhibitory effect on blood vessel formation
and this is crucial for our better understanding of disease mechanisms and possibly developing new forms of therapy says Associate professor Kristensen.
The researchers isolated their antibodies from a library consisting of billions of different antibodies and they subsequently analysed the ability of the individual antibodies to inhibit blood vessel formation.
This sounds like incredibly extensive laboratory work and it would have been far from possible just a few years ago.
However they used a biological technology for this purpose that they developed and published in Nature Protocols three years ago.
It helps them to identify and extract the antibodies with specific binding properties regarding the surface proteins in blood vessel cells.
In the coming years the researchers will work on gaining a more in depth understanding of the ten antibodies.
We're at the stage where we've identified some antibodies that bind something or other that makes blood vessel replication behave differently.
In the coming years we'll study how they behave in different test systems. This will provide us with insight that can be valuable in the long term
when developing new cancer drugs says Associate professor Kristensen n
#Laser-generated surface structures create extremely water-repellent self-cleaning metals Super-hydrophobic materials are desirable for a number of applications such as rust prevention anti-icing or even in sanitation uses.
However as Rochester's Chunlei Guo explains most current hydrophobic materials rely on chemical coatings. In a paper published today in Journal of Applied Physics Guo
and his colleague at the University's Institute of Optics Anatoliy Vorobyev describe a powerful and precise laser-patterning technique that creates an intricate pattern of micro
-and nanoscale structures to give the metals their new properties. This work builds on earlier research by the team in which they used a similar laser-patterning technique that turned metals black.
Guo states that using this technique they can create multifunctional surfaces that are not only super-hydrophobic but also highly-absorbent optically.
Guo adds that one of the big advantages of his team's process is that the structures created by our laser on the metals are intrinsically part of the material surface.
That means they won't rub off. And it is these patterns that make the metals repel water.
The material is so strongly water-repellent the water actually gets bounced off. Then it lands on the surface again gets bounced off again
and then it will just roll off from the surface said Guo professor of optics at the University of Rochester.
That whole process takes less than a second. The materials Guo has created are much more slippery than Teflon--a common hydrophobic material that often coats nonstick frying pans.
Unlike Guo's laser-treated metals the Teflon kitchen tools are not super-hydrophobic. The difference is that to make water to roll off a Teflon coated material you need to tilt the surface to nearly a 70-degree angle before the water begins to slide off.
You can make water roll off Guo's metals by tilting them less than five degrees. As the water bounces off the super-hydrophobic surfaces it also collects dust particles
and takes them along for the ride. To test this self-cleaning property Guo and his team took ordinary dust from a vacuum cleaner
and dumped it onto the treated surface. Roughly half of the dust particles were removed with just three drops of water.
It took only a dozen drops to leave the surface spotless. Better yet it remains completely dry.
Guo is excited by potential applications of super-hydrophobic materials in developing countries. It is this potential that has piqued the interest of the Bill and Melinda Gates Foundation
which has supported the work. In these regions collecting rain water is vital and using super-hydrophobic materials could increase the efficiency without the need to use large funnels with high-pitched angles to prevent water from sticking to the surface says Guo.
A second application could be creating latrines that are cleaner and healthier to use. Latrines are a challenge to keep clean in places with little water.
By incorporating super-hydrophobic materials a latrine could remain clean without the need for water flushing.
But challenges still remain to be addressed before these applications can become a reality Guo states.
It currently takes an hour to pattern a 1 inch by 1 inch metal sample
but ultra-short laser pulses to change the surface of the metals. A femtosecond laser pulse lasts on the order of a quadrillionth of a second
Guo is keen to stress that this same technique can give rise to multifunctional metals. Metals are naturally excellent reflectors of light.
That's why they appear to have a shiny luster. Turning them black can therefore make them very efficient at absorbing light.
The combination of light-absorbing properties with making metals water repellent could lead to more efficient solar absorbers--solar absorbers that don't rust
Guo's team is now planning on focusing on increasing the speed of patterning the surfaces with the laser as well as studying how to expand this technique to other materials such as semiconductors
or dielectrics opening up the possibility of water repellent electronics. Funding was provided by the Bill & Melinda Gates Foundation and the United states Air force Office of Scientific research h
#First public lighting system that runs on solar and wind energy This system developed after four years of research is designed for inter-urban roads motorways urban parks and other public areas.
and is fitted with a solar panel a wind turbine and a battery. The turbine runs at a speed of 10 to 200 revolutions per minute (rpm)
and has a maximum output of 400 watts (W). The developers'aim is to make the lighting system even more environmentally efficient so work is being done on a second prototype generator that runs at a lower speed (10 to 60 rpm
and has a lower output (100 W). An electronic control system manages the flow of energy between the solar panel the wind turbine the battery and the light.
It takes very little wind to produce energy. The generator that has been developed can start working at a wind speed of only 1. 7 metres per second (m/s)
whereas current wind turbines need more than 2. 5 m/s says Ramon Bargall. This low intensity can provide six nights of electricity without wind
or sun he adds. To date Eolgreen has signed agreements with the port of Huelva and the municipal authorities of Sant Boi de Llobregat Girona and several towns in Andalusia.
In the course of 2015 the company plans to produce 700 of these street lights s
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