#Revving up fluorescence for superfast LEDS Duke university researchers have made fluorescent molecules emit photons of light 1000 times faster than normal--setting a speed record
and making an important step toward realizing superfast light emitting diodes (LEDS) and quantum cryptography.
This year's Nobel prize in physics was awarded for the discovery of how to make blue LEDS allowing everything from more efficient light bulbs to video screens.
While the discovery has had an enormous impact on lighting and displays the slow speed with
which LEDS can be turned on and off has limited their use as a light source in light-based telecommunications.
In an LED atoms can be forced to emit roughly 10 million photons in the blink of an eye.
Modern telecommunications systems however operate nearly a thousand times faster. To make future light-based communications using LEDS practical researchers must get photon-emitting materials up to speed.
In a new study engineers from Duke increased the photon emission rate of fluorescent molecules to record levels by sandwiching them between metal nanocubes and a gold film.
The results appear online October 12 in Nature Photonics. One of the applications we're targeting with this research is said ultrafast LEDS Maiken Mikkelsen an assistant professor of electrical and computer engineering and physics at Duke.
While future devices might not use this exact approach the underlying physics will be crucial. Mikkelsen specializes in plasmonics
which studies the interaction between electromagnetic fields and free electrons in metal. In the experiment her group manufactured 75-nanometer silver nanocubes
and trapped light between them greatly increasing the light's intensity. When fluorescent molecules are placed near intensified light the molecules emit photons at a faster rate through an effect called Purcell enhancement.
The researchers found they could achieve a significant speed improvement by placing fluorescent molecules in a gap between the nanocubes and a thin film of gold.
With the help of co-author David R. Smith the James B. Duke Professor and Chair of Electrical and Computer engineering at Duke they used computer simulations to determine the exact size of the gap needed between the nanocubes
and gold film to optimize the setup. That gap turned out to be just 20 atoms wide.
and make the gaps literally with nanometer precision said Gleb Akselrod a postdoc in Mikkelsen's lab and first author on the study.
They plan to design a system with individual fluorescent molecule placed precisely underneath a single nanocube.
If we can precisely place molecules like this it could be used in many more applications than just fast LEDS said Akselrod.
We could also make fast sources of single photons that could be used for quantum cryptography.
This work was supported by the Lord Foundation of North carolina and the Air force Office of Scientific research (Contract No.
#Getting sharp images from dull detectors Observing the quantum behavior of light is a big part of Alan Migdall's research at the Joint Quantum Institute.
--and sometimes only one photon at a time, using"smart"detectors that can count the number of individual photons in a pulse.
what Migdall calls"stupid"detectors that, when counting the number of photons in a light pulse,
as anything more than zero befuddles these detectors and is considered as number that is known only to be more than zero.
The results of Migdall's new work appear in the journal Applied Physics Letters. Achieving this kind of sharp interference pattern could be valuable for performing a variety of high-precision physics and astronomy measurements.
Because in many measurement environments (such as light coming from astronomical sources) coherent light is not available,
And why use"stupid"detectors? Because they are cheaper to use. The Experiment In the case of coherent light, a coordinated train of waves approach a baffle with two openings (figure, top.
creating a characteristic pattern as recorded by a detector, which is moved back and forth to record the arrival of light at various points.
Each of these two portions of light will strike movable detectors which scan across sideways.
If the detectors could record a whole pattern, they would show that the pattern changes from moment to moment.
if you record not just the instantaneous interference pattern but rather a correlation between the two movable detectors.
when detector 1 observes light at a coordinate x1 how often does detector 2 observe light at a coordinate x2?
Plotting such a set of correlations between the two detectors does result in an interference-like pattern,
the detectors would run into each other. To avoid that a simple partially silvered mirror, commonly called a beam splitter,
That way the two detectors can simultaneously sample the light from virtual positions that can be as close as desired
And what about the use of stupid detectors those for which each"click"denoting an arrival tells us only that more than zero photons have arrived?
so that its limited coherence time is larger than the recovery time of our stupid detectors,
it is possible for the detector to tell us that a specific number of photons were recorded, perhaps 3 or 10,
"In this way, we get dumb detectors to act in a smart way, "says Migdall. This improved counting the number of photons,
or equivalently the intensity of the light at various places at the measuring screen, ensures that the set of correlations between the two detectors does result in an interference-like pattern in those correlations.
So while seeing an interference pattern could not be accomplished with dumb detectors, it could be accomplished by engineering the properties of the light source to accommodate the lack of ability of the detectors
and then accumulating a pattern of correlation between two detectors. Considering that the incoming light has a wavelength of 800 nm,
the pattern is sharper by a factor of 20 or more from what you would expect
#Computerized surveillance system quickly detects disease outbreaks among preschoolers A web-based system that allows preschools
and child care centers to report illnesses to local public health departments could improve the detection of disease outbreaks
according to University of Michigan research to be presented Saturday, Oct 11 at the American Academy of Pediatrics (AAP) National Conference & Exhibition in San diego. Researchers who designed the biosurveillance system will describe how it can be used to track illness trends
and improve public health response to outbreaks during a presentation at 2: 09 p m. PDT in Marina Ballroom Salon E at the San diego Marriott Marquis."For example,
if certain child care centers are reporting the beginning of stomach flu (vomiting and diarrhea), other centers can start taking steps to thoroughly clean to kill any viruses before symptoms occur
or before a major outbreak takes place, "says Andrew N. Hashikawa, M d.,F. A a. P.,a pediatric emergency physician at the University of Michigan's C. S. Mott Children's Hospital.
In addition, if child care providers see that larger centers in their community are reporting flu-like illness,
they can use the data to emphasize to parents the need to have immunized their children against influenza sooner rather than later,
says Hashikawa, who also is assistant professor in the Department of Emergency Medicine, Division of Pediatric Emergency Medicine, at the University of Michigan Medical school.
Children under age 5 generally become sick earlier and more frequently than school-aged children and adults because their immune systems are underdeveloped.
Previously some public health departments have found that school absenteeism as a marker for illness was delayed imprecise
"However, child care or preschool absences are typically more likely to be associated with illness and most young children continue to need child care for most of the year,
Most public health departments do not electronically track influenza or stomach illnesses in preschools and child care centers settings."
"Most illness reporting methods used by many public health departments are based slow, paper and inefficient, "says Hashikawa.
They entered data on illness type and symptoms in seven categories commonly seen in preschoolers:
fever, influenza-like illness, pink eye, stomach illnesses (gastroenteritis), cold or respiratory symptoms, ear infections and rash.
Researchers sent data electronically to the public health department weekly or more frequently if spikes in illness cases were seen.
Results showed centers reported 188 individual episodes of illness from Dec 10, 2013, through March 28, 2014.
The most common illnesses reported were gastroenteritis (37 percent), fever (31 percent), cold (17 percent) and influenza (3 percent.
Data also revealed an unusually large increase in gastroenteritis cases during a two-day period,
"Preliminary data suggest that using the online biosurveillance in child care centers and preschools gives us an earlier detection
and warning system because the younger children appeared to become sick first compared to middle school
and high school aged children within the community,"says Hashikawa a
#Sensor invented that uses radio waves to detect subtle changes in pressure Stanford engineers have invented a wireless pressure sensor that has already been used to measure brain pressure in lab mice with brain injuries.
The underlying technology has such broad potential that it could one day be used to create skin-like materials that can sense pressure leading to prosthetic devices with the electronic equivalent of a sense of touch.
A nine-member research team led by Chemical engineering Professor Zhenan Bao detailed two medical applications of this technology in Nature Communications.
In one simple demonstration they used this wireless pressure sensor to read a team member's pulse without touching him.
In a more complex application they used this wireless device to monitor the pressure inside the skull of a lab mouse an achievement that could one day lead to better ways to treat human brain injuries.
Bao's wireless sensor is made by placing a thin layer of specially designed rubber between two strips of copper.
The copper strips act like radio antennas. The rubber serves as an insulator. The technology involves beaming radio waves through this simple antenna-and-rubber sandwich.
When the device comes under pressure the copper antennas squeeze the rubber insulator and move infinitesimally closer together.
That tiny change in proximity alters the electrical characteristics of the device. Radio waves passing through the two antennas slow down in terms of frequency.
When pressure is relaxed the copper antennas move apart and the radio waves accelerate in frequency.
The engineers proved that this effect was measurable giving them a way to gauge the pressure exerted on the device by tracking the frequency of radio waves passing through the device.
Former Stanford graduate students Lisa Chen and Benjamin C-K Tee designed and modeled the physics behind the device
and calibrated the pressure sensor in simple laboratory tests. Alex Chortos graduate student in the department of materials science and engineering made the wireless device more robust and reusable.
When the engineers sought collaborators to test the device in potentially useful applications H.-S. Philip Wong a professor of electrical engineering connected them with Victor Tse a neurosurgeon and consulting associate professor at Stanford School of medicine.
Tse tested the wireless pressure sensor as a tool for managing patients with severe brain trauma.
The most devastating problem in such cases is brain swelling. Currently physicians diagnose brain swelling with imaging techniques such as CT SCANS or by monitoring intracranial pressure (ICP) directly.
ICP monitoring is done traditionally using probes that penetrate the skull and are linked to an external monitor via a cable.
In addition to the possibility of the cable being pulled out or dislodged this cumbersome solution carries the risk of infection.
Measuring ICP using cables become particularly challenging when patients are moved within the hospital or transported to other facilities.
In experiments on laboratory mice Tse used radio waves to probe Bao's wireless sensor allowing him to monitor changes in intracranial pressure continuously.
Our team is now considering how to incorporate this device into a catheter that could siphon out cerebral spinal fluid
whenever there is an increase in ICP Tse said. On a slightly different tack his team is thinking about how to retool the wireless sensor
so that it could be placed in the eye socket. There it could be used to measure pressure in the eye socket a relatively easy-to-obtain surrogate for tracking intracranial pressure on the brain.
In a separate effort Dr. Michael Mcconnell a professor of cardiovascular medicine used the device to take a wireless pulse reading as a proof of principle that the technology could be applied to pressures having to do with blood circulation.
For Bao this is the latest in a series of experiments that capitalize on a simple
Simple as it may seem her lab discovered that creating a pyramid-shaped layer of rubber instead of a flat mat gave the individual rubber molecules more freedom to flatten out and then spring back into shape.
By putting this pyramid-shaped rubber layer between the copper antennas this team of engineers was able to exploit the subtle interactions of radio waves
and consumes no energy until readings are being made she said. In the short term we hope to use devices like this to track packages
most are prescribed for outpatient acute respiratory tract infections. Because antibiotic prescribing is often inappropriate Jeffrey S. Gerber M d. Ph d. of Children's Hospital of Philadelphia
and colleagues recently conducted a randomized trial of an outpatient antimicrobial stewardship intervention that found a nearly 50 percent relative reduction in prescribing rates for broad-spectrum antibiotics according to background information in the article.
To assess the durability of this intervention the researchers followed antibiotic prescribing across intervention and control sites after termination of audit and feedback.
The randomized trial was conducted within 18 community-based pediatric primary care practices using a common electronic health record.
The intervention included clinician education comprising a 1-hour review of current prescribing guidelines for the targeted conditions;
Following termination of audit and feedback however prescribing of broad-spectrum antibiotics increased over time reverting to above-baseline levels After restandardization of the data set for the additional 18 months of data antibiotic prescribing increased from 16.7 percent
These data suggest that audit and feedback was a vital element of this intervention and that antimicrobial stewardship requires continued active efforts to sustain initial improvements in prescribing.
One protein directs epigenetic players Every single human cell contains every single human gene. But depending on the cell only some of these genes need to be expressed or turned on.
When one of these wrong genes is turned on by mistake the result can be rampant cell growth--cancer.
Now scientists know that there are tiny proteins--epigenetic proteins--that sit atop the genetic code inside cells.
Now UNC researchers discovered that one gene-regulating protein called Bre1 must be maintained in the proper amount for other epigenetic players to do their jobs properly.
This supporting staff provides the script and cues for what the genes are supposed to say
All this supporting staff is part of epigenetics--epi meaning on or above--a field that focuses on the environment and the players that allow our genes to act.
I think epigenetics is a new frontier of cancer research says Brian Strahl Ph d. a professor of biochemistry and biophysics in the UNC School of medicine.
We can now sequence the entire genome of a cancer cell and what we're finding is that many cancers have mutations in the epigenetic machinery.
We're not just finding this in cancer cell lines in the lab but in cancer patients.
The director's cutstrahl who's a member of the UNC Lineberger Comprehensive Cancer Center said major questions surround how histones wrap up the DNA into chromatin--a structure that allows
or denies access to the genetic information inside our cells. This is what Strahl studies. His goal is to figure out precisely how histones contribute to basic biological functions
and in turn contribute to cancers and other diseases. Adding a twist to this idea however is the fact that not every histone is the same.
We've already learned that the histone proteins found at the sites of genes can be modified chemically with a variety of small chemical tags that either promote
or further prevent access to our genetic information--our DNA. And this access or denial ultimately affects genes
so they are activated either or not. These chemical tags come from a variety of sources--mainly the food we eat the chemicals in the environment that gets inside us through our skin
and lungs for example and the various biological chemicals that simply make us tick. Proper nutrients for instance allow for the formation of chemical tags to direct the histones to activate genes in the proper ways.
Nasty environmental stuff such as cigarette smoke can mess up the epigenetic machinery. Yet these chemical tags are not ultimately in charge of the genes.
Another layer of proteins above the histones are responsible for putting on the chemical tags. Something has to ensure that these chemical tags on histones are regulated properly to ensure that the tags are only present on the right genes at the right time Strahl said.
Strahl and graduate student Glenn Wozniak focused on one of the proteins that add these chemical tags--a protein called Bre1
which keeps one tag--ubiquitin--in check. In a sense Bre1 hires ubiquitin; it allows ubiquitin to do its job.
Ubiquitin is known to help a histone open up the cell's chromatin to expose genes for activation.
what had been an epigenetic mystery. Scientific literature on Bre1 had been mixed. Some studies indicated that Bre1 had a role as a tumor suppressor Strahl said.
Other studies showed that it's a cancer promoter. So there's been conflicting evidence about all of this.
Now we know. If there's too little Bre1 the gene won't turn on. This could turn off the genes that protect the cell from cancer.
If there's too much Strahl said. Then the genes might not turn off. This could also trigger cancer development.
When you think about it Bre1 could be a really good target for a cancer drug Strahl said.
The above story is provided based on materials by University of North carolina School of medicine. The original article was written by Mark Derewicz.
Blocking STAT3 could help cancer patients in two ways The STAT transcription factors are involved in the development of many forms of cancer.
so drugs targeting STAT3 could be used in cancer therapy. However STAT3 is also important in the development of the immune system.
Dagmar Gotthardt and colleagues at the Vetmeduni Vienna now show that blocking STAT3 in cells of the immune system actually leads to increased anti-tumour immunity.
Anti-STAT3 therapy may thus be highly promising. The so-called Signal Transducers and Activators of Transcription or STATS are key components of many different signalling pathways.
Not surprisingly then when something goes wrong with their regulation the consequences can be severe and many types of cancer are known to be associated with increased activities of one or more STAT protein.
Considerable efforts are going into developing inhibitors of STAT3 for use in cancer therapy but it is unclear
The intriguingly named Natural Killer (NK) cells represent the first line of defence against viruses and cancer to
The issue has been tackled by Dagmar Gotthardt and colleagues in the Institute of Pharmacology and Toxicology of the University of Veterinary medicine Vienna (Vetmeduni Vienna.
Surprisingly the loss of STAT3 in NK cells of the mouse led not to a decrease but to an increase in killing activity against melanoma cells and leukemia cells.
The decrease in metastasis caused by melanoma cells was especially dramatic and confirmed that NK cells lacking STAT3 are extremely efficient killers of tumour cells.
thus help cancer patients in two ways both stopping the cancer cells from dividing and helping the patients'NK cells to fight them more efficiently.
#Scientists create mimic of good cholesterol to fight heart disease, stroke Scientists at The Scripps Research Institute (TSRI) have created a synthetic molecule that mimics oodcholesterol
a condition where plaque buildup in the arteries can cause heart attacks and strokes. therosclerosis is the number one killer in the developed world,
said TSRI Professor M. Reza Ghadiri, senior author of the new study with TSRI Assistant professor of Chemistry Luke Leman. his research clears a big step toward clinical implementation of new therapies.
Good vs. Bad Cholesterol To combat atherosclerosis, researchers are looking for new ways to target
and remove low-density lipoprotein (LDL) cholesterol (commonly known as adcholesterol) from the body. Though the body needs some LDL to stay healthy, high levels lead to dangerous plaque buildups.
A Surprising Finding In collaboration with Linda Curtiss, formerly a faculty member at TSRI, and Bruce Maryanoff, formerly at Johnson & johnson and currently a visiting scholar at TSRI, the researchers tested this synthetic peptide in a mouse model prone to atherosclerosis.
The team originally used the synthetic peptide in an experiment the researchers thought was a gamble.
and a 50 percent reduction in the size of plaque lesions in their hearts. e were surprised definitely at the results in the oral feeding studies,
Many cholesterol treatments currently in development rely on an injection, not a pill. With the option of an orally effective peptide, Ghadiri believes researchers are closer to developing an accessible new therapy for atherosclerosis.
The researchers also reported no signs of increased inflammation in the blood or toxicity after 10 weeks of the peptide treatment.
Future Studies Point to Gut Ghadiri and his team are now investigating exactly how the synthetic peptide works in the intestines
and the possibility that it interacts with beneficial microbes. The researchers believe that finding new targets in the gastrointestinal tract could lead to new therapies for many more diseases. hat one of the fun things in scienceow we get to follow up on these different avenues,
said Leman. In addition to Ghadiri, Leman, Zhao, Curtiss and Maryanoff, other contributors to the study, n vivo efficacy of HDL-like nanolipid particles containing multivalent peptide mimetics of apolipoprotein A-1,
Because his son had a fever the doctors at the clinic put him on first one
and then a second antibiotic while they worked on a diagnosis. They soon learned his son's appendix had burst
Things moved so fast he was septic before he was symptomatic for appendicitis Kinch said.
His son was moved to an academic medical center where he had surgery and was put on four newer antibiotics.
Stunningly the two that worked were the older drugs he had been given at the clinic. I can only assume that
if we had gone straight to the academic medical center he might not have survived Kinch said. It's not that my son had had extensive exposure to antibiotics Kinch explained carefully.
The institute was picking the therapeutic areas that would be their focus. They were considering various exotic diseases
and I said'Antibiotics.''Antibiotics are crashingin his last position as managing director of the Center for Molecular Discovery at Yale university Kinch had assembled a huge database of information about drug discovery and development in the pharmaceutical industry.
He has been able to excavate story after story from this storehouse of data. The crash of antibiotics is one of the best known and scariest
since losing antibiotics would force changes in almost every area of medical practice. In an article in Drug Discovery Today Kinch summarized the financial constraints that have led to the current crisis in antibiotic supply.
The number of antibiotics available for clinical use Kinch said has declined to 96 from a peak of 113 in 2000.
because they're too toxic or because they've been replaced by new versions of the same drug.
which is now dominated by small companies such as Cubist Pharmaceuticals formed in 1992 specifically to focus on drugs for resistant bacterial infections that could have higher price points.
They include for example an acne medication and a treatment for anthrax developed for use in case of a bioterrorist attack.
One reason pharmaceutical companies are said withdrawing Kinch is that our patent law squeezes them for time.
Because of rising resistance doctors hold new antibiotics in reserve using them only in cases of dire need.
If you've got this vancomycin-like situation where the drug is sitting on a shelf--quite literally sitting on a shelf--how is a company going to make its money back?
It is now 30 percent below 2009 levels in constant dollars. Since the NIH has fallen victim to congressional gridlock people in the biomedical community are starting to organize on their own.
The group Kinch helped found the Institute for Life sciences Collaboration recently convened an expert panel at the United nations to discuss the need for innovative partnerships
and financing models to deal with antibiotic resistance. One popular idea is de-linkage or finding a way to disconnect the costs of development from the sale of pills.
Some have suggested that large prizes of $1 billion or more be offered for the development of new drugs
which would then be sold for modest prices by other companies. The Infectious diseases Society of America (ISDA) has launched a 10 x 20 initiative
whose goal is to create global antibacterial drug research-and-development enterprise with the power in the short-term to develop 10 new safe and effective antibiotics by 2020.
Britain is offering a prize of £10 million called the Longitude Prize 2014 (after the prize once offered for an accurate way to determine the longitude of ships at sea) for a rapid test that would allow health professionals to identify bacteria quickly
Newly arrived at Washington University in St louis Kinch is just beginning to think about the role the university might play in redefining its role.
He points out that the university excels in biomedical research but is losing brilliant ideas in the Valley of Death between the lab and the market.
Led by Provost and Executive Vice chancellor H. Holden Thorp Phd an enterpreneurship team has been convened to redefine what the university does with biomedical discoveries after the peer-reviewed articles are in print.
One of the university's assets is School of medicine research with the human microbiome the trillions of organisms that live in our guts many performing beneficial tasks such as digesting food and fighting off infections.
Work the microbiome was pioneered by Washington University scientists led by Jeffrey Gordon MD the Dr. Robert J. Glaser Distinguished University Professor and director of the Center for Genome Sciences and Systems Biology.
and development in part because they underpin every part of modern medical practice from surgery to cancer treatment and pretty much everything in between.
The above story is provided based on materials by Washington University in St louis. The original article was written by Diana Lutz.
Overtext Web Module V3.0 Alpha
Copyright Semantic-Knowledge, 1994-2011