Posts tagged with "rice university"

Fighting Antibiotic Resistance

To combat the rise of drug-resistant bacteria, researchers are examining how one superbug adapts to fight an antibiotic of last resort, hoping to find clues that can prolong the drug’s effectiveness.

At Rice University and the University of Texas Health Science Center at Houston ran experiments to track the biochemical changes that vancomycin-resistant Enterococci (VRE) underwent as they adapted to fight another antibiotic, daptomycin. “We need to get to a stage where we can anticipate how these pathogens will become resistant to antibiotics so we can stay one step ahead of them,” said Rice biochemist Yousif Shamoo, co-author of a study in the journal Antimicrobial Agents and Chemotherapy that found VRE can develop resistance to daptomycin in more than one way. The stakes are high. In 2014, the World Health Organization reported that antibiotic-resistant infections were on pace to kill 10 million people per year worldwide by 2050.

According to the U.S. Centers for Disease Control, VRE is one of the nation’s leading antibiotic resistance threats. The CDC estimated VRE will infect some 20,000 people in the U.S. this year and kill 1,300 of them. Daptomycin, an antibiotic that first became available in 2003, is one of the last drugs doctors can use to fight multidrug-resistant superbugs like VRE, methicillin-resistant Staphylococcus aureus (MRSA) and glycopeptide resistant enterococci (GRE). Unfortunately, health officials documented cases of daptomycin resistance as early as 2005, and the number of cases is on the rise worldwide.

Shamoo said one of the principle findings of the study was that a specific strain of VRE, Enterococcus faecium, has an unusually diverse set of strategies for resisting antibiotics like daptomycin, and that diversity can make treatment of infections even more difficult. “By understanding how these pathogens acquire resistance, we can develop new treatment strategies or new ‘co-drugs’ that target their ability to become resistant,” Shamoo said. Co-drugs that target the evolution of resistance could be administered with antibiotics like daptomycin to both help patients fight off infection and stem the spread of increasingly resistant strains of bacteria in hospitals, he said.

Study lead author Amy Prater, a Ph.D. student who graduated from Rice in July, showed that the same strain of VRE could activate different biochemical pathways to activate up to three strategies, depending upon its environment. Shamoo said the multipronged strategy will make it more difficult for health officials to fight growing daptomycin resistance in VRE, but he said the results help clear up previously confusing experimental findings about VRE resistance, which is a step in the right direction. “If we understand how a pathogen acquires resistance, we can anticipate its next move, and hopefully act beforehand to cut it off,” Shamoo said. “Predictability is the key.”

Shamoo is Rice’s vice provost for research and a professor of biochemistry and cell biology in the Department of BioSciences. Additional co-authors include Heer Mehta and Abigael Kosgei of Rice and William Miller, Truc Tran and Cesar Arias of the UTHealth McGovern Medical School.

Student Invention Gives Patients the Breath of Life

Natalie Dickman squeezed the bag again and again in an effort to revive a victim of cardiac arrest. After a mere 3 minutes, she could squeeze no more. 

“The patient had been down for 30 minutes and there wasn’t much hope, unfortunately,” said the Rice University student, a soon-to-be graduate of the Brown School of Engineering, who was covering a shift with Houston EMS as required by a Rice class in emergency medical techniques. “I was allowed to bag, but they make you switch in EMS settings because they know you won’t be as accurate once you hit that 2-to-3-minute mark. You get really tired.”

She thought about that often over the last year when she and her senior teammates worked at Rice’s Oshman Engineering Design Kitchen (OEDK) to perfect a cost-effective device that automates the compression of manual bag valve masks, which feed fresh air to the lungs of intubated patients. 

The senior capstone design team — bioengineering students Dickman, Carolina De Santiago, Karen Vasquez Ruiz and Aravind Sundaramraj, mechanical engineering and computational and applied mathematics student Tim Nonet and mechanical engineering student Madison Nasteff — is known as “Take a Breather.” 

The team has developed a system that compresses the bags for hours, rather than minutes, with settings to feed the right amount of air to adults, children and infants. The device seems simple — a box with paddles that rhythmically squeeze the bulb a programmed amount – but the engineering behind it is not.

The students used a $25, off-the-shelf motor and $5 microcontroller to power and program the rack-and-pinion device made primarily of plastic parts 3D-printed at the OEDK. They hope their use of inexpensive materials and the growing availability of 3D printers will make their machines easy to repair on-site.

They anticipate the device, which cost them $117 in parts to build, will be most useful in low-resource hospitals or during emergencies when there aren’t enough portable ventilators to meet the need. 

Dr. Rohith Malya, an assistant professor of emergency medicine at Baylor College of Medicine, brought the problem to the OEDK after witnessing family members at the Kwai River Christian Hospital in Thailand, where he is director of emergency medical services, squeezing intubation bags for hours on end to keep loved ones alive. 

“There is no reliable ventilation,” said Malya, who spends a month at the hospital every year. “Once we intubate somebody, the family has to bag the patient. But the family will get tired after a day and say, ‘They’re not getting better right now, just pull the tube and see what happens.’ And then the patient dies.”

Malya previously worked with Rice engineering students to develop a syringe regulating pump, and did not hesitate to bring a new idea to the OEDK. 

“The bag mask is ubiquitous, like the syringe,” he said. “Nothing has challenged it for 80 years. It’s stood the test of time, it’s reliable and it’s simple. And now we’re adding a modification to the original device so families don’t have to make those decisions.

“This will broaden the access to mechanical ventilation to a tremendous part of the world that doesn’t have typical ventilators,” said Malya, who plans to take the proof-of-concept device to Thailand for field testing next spring. 

The device is much smaller than the sophisticated ventilators found in American hospitals and portable versions used in emergency situations. Critically, it has to be able to operate for long stretches. In its most recent test, the team ran the device for more than 11 hours without human intervention.  

The students expect another Rice team will build a more robust version next year, and hope it will eventually be manufactured for use in low-resource and emergency settings. They anticipate a better-sealed and filtered box will be more suitable for hot, dusty environments, and said future designs should include more sophisticated controls.

For its efforts this year, the team won two prizes at the school’s annual Engineering Design Showcase, the Willy Revolution Award for Outstanding Innovation and the best interdisciplinary engineering design award. But the real payoff would be seeing the device further developed and deployed around the world. 

“If they can get it working fully in that kind of environment, this will be saving lives,” Nasteff said.

Rice U. Device Would Help Fix Fractured Bones

Threading a needle is hard, but at least you can see it. Think about how challenging it must be to thread a screw through a rod inside a bone in someone’s leg.

Rice University seniors at the Brown School of Engineering set out to help doctors simplify the process of repairing fractured long bones in an arm or leg by inventing a mechanism that uses magnets to set things right.

The students who call themselves Drill Team Six chose the project pitched by Rice alumnus Dr. Ashvin Dewan, an orthopedic surgeon at Houston Methodist Hospital, to simplify a procedure by which titanium rods are placed inside broken bones to make them functional once more. For its efforts, the team won the top prize, the Excellence in Engineering Award, at the school’s annual

Engineering Design Showcase.  

The student team — bioengineering majors Babs Ogunbanwo, Takanori Iida, Byung-UK Kang and Hannah Jackson and mechanical engineering majors Will Yarinsky and Ian Frankel — learned from Dewan that surgeons require many X-rays to locate pre-drilled 5 millimeter holes in the rod. The holes allow them to secure the rod to the bone fragments and hold them together.

The surgery typically requires doctors to insert the long rod with a guide wire inside into the end of the bone, drilling through marrow to align the fractured fragments. With that done, they depend on X-rays, their experience and, if necessary, a bit of trial and error to drill long surgical screws through one side of the bone, thread it through the rod and secure it to the other side.

“We want to reduce the amount of X-rays, the surgeon’s time, the operating room time, the setup time, everything,” Yarinsky said.

The Rice team would make the wire adjacent to the holes magnetic, because neither skin nor bone hinder a magnetic field

“That way, the magnets hold their position and we can do the location process,” Frankel said. “Once we’ve found them and secured the rod, we remove the wire and the magnets with it.”

The exterior mechanism is a brace that can be securely attached to the arm or leg with Velcro. A mounted sensor can then be moved along the stiff, 3D-printed carbon-fiber rods or around the limb until it locates the magnet. Then, the angle of the sensor can be adjusted. As each of the three degrees of freedom come into alignment with the target, a “virtual LED” lights up on a graphic display wired to the sensor. Then, the sensor is removed and a drill keyed to the mechanism inserted.

“We do the angular part because the rod is not in the center of the leg, and the hole is not necessarily perpendicular to the surface,” Yarinsky said. “The rod is about 10 to 20 millimeters thick and has a hole on one side and a hole on the other. We don’t want to hit the first hole at an angle where we miss the second

and don’t go all the way through.”

Working at Rice’s Oshman Engineering Design Kitchen (OEDK), the team tested its device on a mannequin leg and what it called a “wooden leg,” a frame that allowed for mounting the rod with its magnetized wire and checking the accuracy of their system.

Before it can be used by clinicians, the team said the device will require Food and Drug Administration approval.

“I’m very impressed with what the team put together,” said Dewan, who earned a bioengineering degree at Rice in 2005. “Where we ended up is completely different from what we imagined, but kudos to these guys. They went through many different proposals and ideas and ended up running with the one that seemed most promising.”

Having been through the senior capstone process at Rice himself, Dewan was particularly impressed with how the program has grown.

“The OEDK got off the ground a few years after I graduated, and at that point, senior design projects were isolated to individual projects,” Dewan said. “I didn’t work with mechanical or other engineering disciplines.

“I love the way they have a multidisciplinary approach to tackling problems,” he said.  “I think it’s much more of a real-world experience for them.”

Sabia Abidi, a lecturer in bioengineering, served as the team’s adviser, and it was sponsored by Chuck and Sharon Fox. ­­

AUTOMATED CAR DANGERS

Warning: Automated cars and their operators fail to detect dangers

Automated cars are becoming more common, but they still require drivers to react to dangers that aren’t detected by an automated system. New research from Rice University and Texas Tech University has found that drivers often fail to spot hazards missed by automated vehicles, and it only gets worse the longer drivers ride in them.

 

The study, “Driver Vigilance in Automated Vehicles: Effects of Demands on Hazard Detection Performance,” will appear in an upcoming edition of Human Factors. 

 

The researchers examined the behavior of 60 licensed drivers operating an automated car in a simulator. Participants were told that due to the automation, they would not need to operate the steering wheel, brake pedal or accelerator pedal. They were instructed to monitor the roadway for vehicles that were stopped dangerously at intersections and intruding into the driver’s lane, which constituted a hazard that automated vehicles could not detect. Participants also had to distinguish between vehicles that were safely stopped and dangerously stopped at intersections.
 

The drivers’ accuracy dropped between 7 and 21 percent over the 40-minute simulation. Even in the first 10 minutes the success rate was, at best, close to 88 percent, suggesting that all drivers missed at least some hazards.

 

So why did this happen?

 

Pat DeLucia, a professor of psychological sciences at Rice and the study’s co-author, said that one possibility is that people get used to cars doing the driving and become complacent. Coupled with previous research that indicated people are terrible at monitoring for hazards that only happen every once in a while, and that over time their ability to respond decreases, the new study “suggests that this phenomenon of difficulty monitoring effectively over time extends to monitoring an automated car,” DeLucia said. 

 

“The bottom line is, until automated driving systems are completely reliable and can respond in all situations, the driver must stay alert and be prepared to take over,” said Eric Greenlee, an assistant professor of psychological sciences at Texas Tech and the study’s lead author. “And this research clearly shows that is not happening, and gets worse as time passes.” 

 

The researchers hope this work will add to the growing body of research about the safety of automated cars. 

 

“These vehicles have a lot to offer, but we’re a long way from being able to detect everything going on,” the researchers wrote. “Until that day comes, we hope this research will raise awareness about the limitations of automated cars and their operators.” 

 

The study was co-authored by David Newton, a graduate student at Texas Tech.