Research Notes
Sensors packed in single fiber for harsh environments
By fusing the concepts of active fiber sensors and high-temperature fiber sensors, a team of Swanson School of Engineering researchers has created an all-optical high-temperature sensor for gas flow measurements that operates at record-setting temperatures above 800 degrees Celsius.
Led by Kevin P. Chen, faculty member and the Paul E. Lego Faculty Fellow in the Department of Electrical and Computer Engineering, the team’s technology is expected to find industrial sensing applications in harsh environments ranging from deep geothermal drill cores to the interiors of nuclear reactors to the cold vacuum of space, and it may eventually be extended to many others.
They successfully demonstrated simultaneous flow/temperature sensors at 850 degrees C, which is a 200-degree C improvement on an earlier demonstration of such sensors by researchers at Oak Ridge National Laboratory.
The new approach involves integrating optical heating elements, optical sensors, an energy delivery cable and a signal cable within a single optical fiber. Optical power delivered by the fiber is used to supply energy to the heating element, while the optical sensor within the same fiber measures the heat transfer from the heating element and transmits it back.
Said Chen: “We call it a ‘smart optical fiber sensor powered by in-fiber light.’” The team’s work expands the use of fiber-optic sensors well beyond traditional applications of temperature and strain measurements. “Tapping into the energy carried by the optical fiber enables fiber sensors capable of performing much more sophisticated and multifunctional types of measurements that previously were only achievable using electronic sensors.”
In microgravity situations, for example, it’s difficult to measure the level of liquid hydrogen fuel in tanks because it doesn’t settle at the bottom of the tank. It’s a challenge that requires the use of many electronic sensors — a problem Chen initially noticed years ago while visiting NASA, which was the original inspiration to develop a more streamlined and efficient approach.
“For this type of microgravity situation, each sensor requires wire ‘leads’ to deliver a sensing signal, along with a shared ground wire,” said Chen. “So it means that many leads — often more than 40 — are necessary to get measurements from the numerous sensors. I couldn’t help thinking there must be a better way to do it.”
The team looked to optical-fiber sensors, which are one of the best sensor technologies for use in harsh environments, thanks to their extraordinary multiplexing capabilities and immunity to electromagnetic interference. And they were able to pack many of these sensors into a single fiber to reduce or eliminate the wiring problems associated with having numerous leads.
“Another big challenge we addressed was how to achieve active measurements in fiber,” Chen said. “If you study optical fiber, it’s a cable for signal transmission but one that can also be used for energy delivery — the same optical fiber can deliver both signal and optical power for active measurements. It drastically improves the sensitivity, functionality and agility of fiber sensors without compromising the intrinsic advantages of fiber-optic sensors. That’s the essence of our work.”
Based on the same technology, highly sensitive chemical sensors also can be developed for cryogenic environments. “The optical energy in-fiber can be tapped to locally heated in-fiber chemical sensors to enhance its sensitivity,” Chen said. “In-fiber optical power can also be converted into ultrasonic energy, microwave or other interesting applications because tens or hundreds of smart sensors can be multiplexed within a single fiber. It just requires placing one fiber in the gas flow stream, even in locations with strong magnetic interference.”
Next, the team plans to explore common engineering devices that are often taken for granted and search for ways to enhance them. “For fiber sensors, we typically view the fiber as a signal-carrying cable,” Chen said. “But if you look at it from a fiber sensor perspective, does it really need to be round or a specific size? Is it possible that another size or shape might better suit particular applications? As a superior optical cable, is it also possible to carry other types of energy along the fibers for long-distance and remote sensing?”
The research was published in The Optical Society’s journal Optics Letters.
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Ctr. for Medical Innovation funds eight biomed devices
The Center for Medical Innovation (CMI) awarded grants totaling $100,000 to eight research groups through its 2014 round-1 pilot funding program for early stage medical technology research and development. The latest funding proposals include developing a wireless EEG sensor and signal processing system for enhanced monitoring; a bronchial prosthesis to assist lung cancer survivors after surgical removal, and tinted sutures for external surgery that fade to clear to improve aesthetic features.
CMI, housed in the Swanson school, supports applied technology projects in the early stages of development with “kickstart” funding toward the goal of transitioning the research to clinical adoption. Proposals are evaluated on the basis of scientific merit, technical and clinical relevance, potential health care impact and significance, experience of the investigators, and potential in obtaining further financial investment to translate the particular solution to health care.
Said Alan D. Hirschman, CMI executive director: “This early-stage interdisciplinary research helps to develop highly specific biomedical technologies through a proven strategy of linking UPMC’s clinicians and surgeons with the Swanson school’s engineering faculty.”
The awards went to:
• Pamela Moalli, obstetrics, gynecology and reproductive sciences, School of Medicine; Jeffrey Vipperman, mechanical engineering and materials science, Swanson school, and Alan Rosenbaum, resident physician, obstetrics and gynecology, Magee Womens Hospital, to design, build and test an improved morcellation device for laparoscopic surgery, preventing the accidental release of cancerous tissue into the body.
• Salah Al-Zaiti, acute and tertiary care, School of Nursing; Clifton Callaway, emergency medicine, School of Health and Rehabilitation Science, and Ervin Sejdic and Amro El-Jaroudi, electrical and computer engineering, Swanson school, for development of a system for rapid, accurate pre-hospital management of myocardial infarction patients through the use of novel ECG signal processing techniques.
• Stephen P. Emery, obstetrics, gynecology and reproductive sciences, School of Medicine, and Youngjae Chun, industrial engineering, Swanson school, for development of a fluid drainage shunt for in-utero treatment of fetal hydrocephalus.
• Steven D. Abramowitch, bioengineering, Swanson school, and Pamela Moalli, to design, build and perform in vivo testing of a new class of surgical meshes for treatment of pelvic organ prolapse without the complications of currently marketed devices.
• Two medicine faculty, Parthasarathy D. Thirumala in neurological surgery and neurology and Jeffrey Balzer in neurosurgery, and two Swanson school faculty, Di Gao in chemical and petroleum engineering, and Mingui Sun, bioengineering and electrical engineering, to design, build and test a wireless EEG sensor and signal processing system for use in emergency medicine, critical care and ambulatory monitoring.
• J. Peter Rubin, plastic surgery, medicine, and Eric J. Beckman, chemical and petroleum engineering, Swanson school, for development and testing of a new suture that is highly visible during placement and becomes transparent during patient recovery, thereby improving aesthetic outcomes.
• Charles Sfeir, oral biology, dental medicine, and two Swanson school faculty, Andrew Brown, bioengineering, and Steven Little, chemical and petroleum engineering, for development of a resorbable barrier membrane for faster and lower cost guided bone regeneration (GBR) in periodontal applications.
• Cardiothoracic surgery faculty James D. Luketich and Arjun Pennathur, visiting faculty Diane Strollo and research fellow Valentino Bianco, in medicine, and Swanson school faculty William J. Federspiel in bioengineering and chemical/petroleum engineering, for development of a prosthesis to prevent bronchial kinking after removal of one or more lobes of the lung, helping lung cancer patients avoid post-surgical complications that impact recovery and quality of life.
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Pitt to test Innova Dash electric car
Pitt is one of four universities test-driving the Innova Dash University Electric Vehicle (UEV).
Beginning this month, Pitt will be testing the tiny, two-seat car in collaboration with Internet2, a national consortium of institutions looking to solve common technology challenges.
Pitt researchers will be testing four UEVs, studying how they could help reduce the campus carbon footprint by collecting massive amounts of data from the car’s sensors. The yearlong project also is designed to raise awareness of the “Internet of Things,” a concept used to describe electronic communication between devices such as electric cars and Pitt’s data-collection devices independent of people.
The UEV is a zero-emissions electronic vehicle company, a variation on European micro-car technology, sized between motorcycles and compact vehicles. With a maximum speed of 35 mph and an estimated 100-mile range per charge, the Dash plugs into any standard garage 240-volt outlet at the cost of less than 25 cents a day to operate.
Ervin Sejdic, electrical and computer engineering faculty member in the Swanson school, is leading the UEV effort at Pitt. He believes that one of the most significant areas of research will be “energy optimal routing.” What’s the best way to drive the UEV in general? What are the optimal situations in which to accelerate or brake? How powerfully or how softly should the ideal driver press on the accelerator?
Computing Services and Systems Development (CSSD) and Parking, Transportation and Services each will use one UEV. The Swanson School of Engineering will use two.
Brian Stengel, CSSD, is the project manager/outreach coordinator. Marlin Mickle, emeritus faculty member in electrical and computer engineering, is an adviser on the project.
Colorado State University, the University of Washington and the University of Wisconsin also are testing the Innova Dash.
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Sex hormone levels increase women’s heart disease risk
As hormone levels change during the transition to menopause, the quality of a woman’s cholesterol carriers degrades, leaving her at greater risk for heart disease, researchers at the Graduate School of Public Health have discovered.
Supported by the National Institutes of Health (NIH), the research was done using an advanced method to characterize cholesterol carriers in the blood. Results were published in the Journal of Lipid Research.
Said lead investigator Samar R. El Khoudary, faculty member in epidemiology: “The results call for further research to evaluate the menopause-related dynamic changes in sex hormones on the quality of cholesterol carriers over time, as well as increased emphasis on the importance of healthy diet and exercise for women undergoing menopause. Higher levels of HDL, or what we know as ‘good’ cholesterol, may not always be as protective as we had thought before.”
El Khoudary explained that normal levels of LDL, or “bad” cholesterol, do not imply normal cholesterol levels in all individuals. Rather, quality of cholesterol carriers may provide more accurate information about risk related to levels of cholesterol.
“We found that lower levels of estradiol, one of the main hormonal changes that mark menopause, are associated with low-quality cholesterol carriers, which have been found to predict risk for heart disease,” she said. “Our results suggest that there may be value in using advanced testing methods to evaluate changes in cholesterol carriers’ quality in women early in menopause so that doctors can recommend appropriate diet and lifestyle changes.”
Cholesterol travels through the bloodstream in small particles called lipoproteins, or cholesterol carriers. Conventional blood tests show the amount of cholesterol carried by these lipoproteins, rather than the characteristics of the lipoproteins themselves. There are two major types of lipoproteins: high-density lipoprotein (HDL), which helps keep cholesterol from building up in the arteries, and low density lipoprotein (LDL), the main source of cholesterol buildup and blockage in the arteries. Research studies have shown that the characteristics of LDL and HDL particles, including the number and size of these particles, significantly predict risk of heart disease.
Previous studies evaluating the associations between sex hormones and cardiovascular disease as women went through menopause looked only at cholesterol measured through conventional blood tests. El Khoudary and her colleagues used nuclear magnetic resonance spectroscopy to measure the size, distribution and concentration of lipoproteins that carry cholesterol in the blood.
The Pitt team found that as estrogen levels fall, women have higher concentrations of low-quality, smaller, denser LDL and HDL particles, which are associated with greater risk of heart disease. The conventional blood tests often don’t pick up on such a nuance in particle size.
The study evaluated 120 women from Pittsburgh who were enrolled in the Study of Women’s Health Across the Nation (SWAN). The women were an average of 50 years old and not on hormone replacement therapy.
SWAN is an ongoing study of the biological, physical, psychological and social changes in more than 3,000 middle-aged women who were recruited at seven sites across the U.S. The goal is to help scientists, health care providers and women learn how mid-life experiences affect health and quality of life during aging.
“As a woman transitions to menopause, many biological changes take place that can put her at greater risk of many conditions, including osteoporosis and heart disease,” said El Khoudary. “Our most recent study underscores the importance of having clinicians aware of these risk factors and prepared to work with their patient to help her best mitigate these risks.”
El Khoudary is collaborating with other scientists to identify funding to study a larger sample of women over time to definitively tie changes in hormone levels and the quality of cholesterol carriers with heart disease.
Additional Pitt authors on this study were Maria M. Brooks, Rebecca C. Thurston and Karen A. Matthews.
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Unhappy marriages pose cardiovascular disease risk
The affairs of the heart may actually affect the affairs of the heart in ways previously not understood.
Noted Thomas Kamarck, faculty member in psychology in the Dietrich School of Arts and Sciences: “Growing evidence suggests that the quality and patterns of one’s social relationships may be linked with a variety of health outcomes, including heart disease.”
He is an author of a new study that correlates unhappy marital interaction with thicker carotid arteries and a higher risk of cardiovascular disease.
“The contribution of this study is in showing that these sorts of links may be observed even during the earliest stages of plaque development [in the carotid artery],” Kamarck said, “and that these observations may be rooted not just in the way that we evaluate our relationships in general but in the quality of specific social interactions with our partners as they unfold during our daily lives.”
Nataria Joseph, who recently completed a postdoctoral fellowship under Kamarck, is the lead author of the paper, published in Psychosomatic Medicine. Given the size of the effect in the study and the relationship between carotid artery plaque and disease, Joseph’s findings indicate that those with marital interactions light on the positive may have an 8.5 percent greater risk of suffering heart attack or stroke than those with a surfeit of good feelings.
The study included 281 healthy, employed, middle-aged adults who were married or living with a partner in a marital-like relationship. Their interactions were monitored hourly over the course of four days, with the partners rating their interactions as positive or negative.
Carotid artery thickness also was measured. Those partners reporting more negative interactions were found to have thicker carotids. Joseph says that these associations could not be accounted for by other behavioral or biological risk factors and also were independent of marital interaction frequency, nonmarital social interaction or personality factors. The findings were consistent across age, sex, race and education level.
There are limitations to the study, Joseph said, because it is a cross-sectional study with all the data collected at one point in time. Causality, therefore, has not been proven, though a strong correlation has been established.
“What it does show,” she said, “is that health care providers should look at relationships as a point of assessment. They are likely to promote health or place health at risk.”
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Less toxic HIV drugs may improve life expectancy
While bringing new drugs to market is important for increasing life expectancy in younger people with HIV, lowering the toxicity of those drugs may have an even greater health impact on all HIV patients, a Pitt analysis revealed.
The research, supported by the National Science Foundation (NSF) and NIH and published in the journal PLOS ONE, used a computer simulation to examine what would happen if guidelines for starting HIV treatment took into account the rate of new drug development and the toxicity of those drugs.
Said senior author Mark Roberts of public health’s Department of Health Policy and Management: “The side effects of treatment remain one of the primary reasons that HIV drug regimens are discontinued. By decreasing the toxicity and side effects of HIV drugs, you increase the amount of time that patients can stay on that lifesaving treatment regimen. Some side effects, such as increased cardiovascular risk, also cause problems that directly contribute to premature mortality.”
The simulation, which built upon a model developed at New York University School of Medicine, found that if new HIV drugs are less toxic than existing drugs, those new drugs will increase the patient’s quality-adjusted life expectancy by as much as 11 percent, or more than three years.
“Quality-adjusted life years” and “quality-adjusted life expectancy” are measures that analysts use to determine the value of different medical actions. For example, a potentially lifesaving drug that was highly toxic and left a patient debilitated would have a lower value than a lifesaving drug that didn’t have such side effects.
New HIV drugs are approved for market nearly twice a year and recently revised World Health Organization guidelines on the initiation of HIV treatment recommend that, with this rate of drug development, all HIV patients start treatment before their immune system is significantly compromised.
The Pitt researchers’ simulation backed this recommendation, finding that, even at current drug toxicity levels, young people with HIV add nearly two years to their lives by initiating HIV treatment regimens soon after infection.
Antiretroviral therapy for HIV typically consists of the combination of at least three drugs that help control HIV. However, over time, these drugs become less effective.
In younger patients, doctors have tended to wait longer to start antiretroviral therapy because those patients will have to be on the drugs the longest in order to live an average lifespan. As such, they’ll need the drugs to be effective longer and have fewer side effects.
“This availability of new drugs means that as the drugs a patient is on become less effective, doctors can adjust the therapy to use a new, more effective drug,” said Roberts. “And if that new drug has a low toxicity and is well-tolerated by the patient, then they are more likely to take it regularly so that it is as effective as possible.”
Other researchers on this study were Andrew J. Schaefer, industrial engineering in the Swanson school, and faculty from Clemson University, New York University and the University of Chile.
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$1.8 million grant to build ECG database, study CPR
Pitt researchers have received $1.8 million from the National Heart, Lung and Blood Institute (NHLBI) to create a database of electrocardiogram (ECG) information that could one day be used to better guide real-time decision-making during cardiopulmonary resuscitation (CPR) for cardiac arrest. The database would be the largest repository of its kind and could lead to new ways to evaluate CPR and patient outcomes.
Said lead investigator James Menegazzi, emergency medicine: “We will make use of this information to better understand how the quality of CPR might change the ECG patterns, and then link that to the outcomes of the patient all the way to discharge. If we can see what works best, we can further refine CPR interventions and save more lives.”
Nearly 351,000 Americans experience a sudden cardiac arrest outside the hospital, and fewer than 7 percent survive to hospital discharge. Many of those patients suffer from ventricular fibrillation (VF), a condition in which erratic contraction of the cardiac muscle of the ventricles in the heart impairs the pumping of blood to the lungs and the body. VF is a common cause of cardiac arrest and typically is treated with defibrillation, or a shock, to correct the rhythm, which can look like irregular waves or spikes on the ECG.
The multicenter study will examine data from 10,000 ECG reports collected by the Resuscitation Outcomes Consortium (ROC), a clinical research network funded by the NHLBI. The research team has created a data management and analytic platform that converts ECG information into a uniform format, which will allow them to identify and measure waveform differences and assess which VF episodes respond better to defibrillation than others.
Menegazzi and his team will examine ECG and clinical data from the ROC to identify associations between specific VF patterns and clinical presentations, CPR quality and patient survival rates.
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Aggressive, docile spiders have biological roles
Colin Wright, a PhD student in the Department of Biological Sciences in the Dietrich school, co-authored a paper published in the Proceedings of the National Academy of Sciences delineating spiders’ roles within their colonies.
Spiders’ specializations (caregiver or hunter-warrior) aren’t determined by size or physical structure, as is the case with ants, but by their personalities. While most spiders are solitary, a few species, such as Anelosimus studiosus (found in Tennessee, among other places), live in groups.
Wright and mentor Jonathan Pruitt, faculty member in behavioral ecology, with a colleague at the College of Coastal Georgia, separated the docile spiders from the aggressive by observing how much space they demanded from fellow colony members. Aggressive females demand more space than docile ones.
The team ran the spiders through a series of tests, examining their performance in colony defense, prey capture, parenting skills and web repair. The aggressive cohort was great at defending the web, capturing prey and repairing their web. But they were awful parents.
Said Wright: “We didn’t know what the docile spiders did. Were they just freeloaders?” They were the ones who were capable of rearing large numbers of offspring.
In a separate study, Pruitt also created all docile, all aggressive, and mixed colonies of spiders. The docile colonies died out first; no one was there to protect them from “parasite” spiders that picked off their young and stole their prey. The colony of all aggressors died off second, as they became cannibalistic toward their young. However, the mixed group thrived.
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Telephone depression coaching aids cardiac patients
Screening for depression and then providing a telephone-delivered, nurse-led collaborative-care intervention following coronary artery bypass graft (CABG) surgery not only improves health-related quality of life, physical functioning and mood symptoms, but also lowers medical costs and is highly cost-effective compared to doctors’ usual care, according to School of Medicine researchers.
This analysis of the NIH-funded Bypassing the Blues trial was published in General Hospital Psychiatry.
According to Bruce L. Rollman, faculty member in medicine, psychiatry and clinical and translational science and the study’s principal investigator, while previous research showed this collaborative-care model to be effective for treating post-CABG depression, the latest study establishes the business case to policy makers and insurers for widespread adoption.
Said Rollman: “One of the holy grails in mental health services research is to demonstrate that treating a common mental health condition such as depression is not only effective and cost-effective, but is also cost-saving. This is the first trial to demonstrate all three outcomes. We now know that screening for and then providing effective depression treatment to medically complex patients with cardiovascular disease is very likely to pay for itself.”
A recent American Heart Association science advisory recommends routine screening and treatment of depression in patients with cardiac disease, he noted.
Researchers examined Medicare and private medical insurance claims data for 189 trial participants. After incorporating the $460 average cost to deliver the intervention that included nurse and supervising physician time, patients randomly assigned to the intervention had $2,068 lower median claims costs at one year after bypass surgery compared to those who received their doctors’ usual care ($16,126 vs. $18,194). The intervention also was highly cost-effective, producing more quality-adjusted life-years (QALY), a measure analysts use to determine the value of different medical actions, while significantly lowering medical claims costs by $9,889 per additional QALY generated.
About 400,000 CABG surgeries are performed annually in the U.S., and studies indicate approximately one in five patients who undergo the procedure experiences clinical depression. Extending this $2,068 savings to all depressed post-CABG patients has the potential to save over $165 million in medical claims in the first year following surgery, said Rollman.
The collaborative-care model involves care managers who follow an evidence-based treatment protocol under the supervision of a primary care physician. The team systematically contacts patients to monitor their mood symptoms and recommends appropriate adjustments in treatment. Although team-based collaborative care for depression has yet to be widely adopted, it is increasingly being provided by integrated health care systems through patient-centered medical homes supported by payment reforms under the Affordable Care Act.
Collaborators on this study included Julie M. Donohue, Mark S. Roberts and Aiju Men of the Department of Health Policy and Management in the Graduate School of Public Health; Bea Herbeck Belnap of the Center for Research on Health Care; Charles F. Reynolds III, faculty member in geriatric psychiatry, neurology, behavioral and community health sciences, and clinical and translational science; Fanyin He, a graduate student researcher at UPMC, and a faculty member at Weill Cornell Medical College.
The research was supported by the Fine Foundation and by the National Heart Lung and Blood Institute of NIH.
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