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Biomedical Engineering

The Biomedical Engineering blog is the place for conversation and discussion about topics related to engineering principles of the medical field. Here, you'll find everything from discussions about emerging medical technologies to advances in medical research. The blog's owner, Chelsey H, is a graduate of Rensselaer Polytechnic Institute (RPI) with a degree in Biomedical Engineering.

The Deal with DEET

Posted July 05, 2014 12:00 AM by Chelsey H

One of the worst things about summertime is the increase in mosquitos and other biting, buzzing, and annoying insects. Image Credit

Many of us turn to insect repellent sprays, candles, or lotions to keep the bugs from making us their dinners, but do you know if those products are safe? DEET, a popular insect repellent, is used by an estimated 30 percent of Americans every year, and researchers estimate people around the world put on DEET 200 million times a year.

DEET (N,N-diethyl-meta-toluamide) has been sold to US consumers since the 1950s and was originally developed by the US Army. Here is a great video about DEET.

The Good

DEET has been the focus of dozens of studies, all of which show the product is generally safe and, contrary to many internet reports, does not cause nervous system damage and very rarely causes skin reactions. One study followed women in Thailand who used DEET during pregnancy and found that, not only did the women have less incidences of malaria, but the babies born were healthy and of the same weight, length, and head circumference as babies born to women not using DEET.

British experts say more harm occurs when people use too little DEET and put themselves at risk of harmful insect-borne diseases.

The Bad

As with any chemical there are risks. In concentrations of 50 percent and above (which does not act as a better repellent) DEET has been shown to cause allergic skin reactions and eye irritation. In 2013, 4,000 DEET-related calls were made to poison control centers. Most serious symptoms, such as seizures, slurred speech, coma, and death, occurred in people who ingested DEET, applied it for three or more days in a row, or used products with 95 percent DEET or more.

To Sum It Up

Doctors in countries where people are at a greater risk of insect-borne diseases, such as malaria or West Nile virus, recommend using DEET in concentrations between 20 and 50 percent. They also recommend that in children, seniors, and those with weakened immunity use extra caution when handling DEET.

And there are plenty of ways to avoid mosquitos while also avoiding DEET.

- When you're sitting on a deck or patio, plug in a fan to blow away mosquitoes.

- If you need a repellent, first try plant-based products. If you opt for DEET, use products with appropriate concentrations, such as Off Family-Care Smooth & Dry spray.

- Don't drink as much beer (outside)

What's your solution to keeping the bugs away?

10 comments; last comment on 07/08/2014
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Genome Editing

Posted May 31, 2014 12:00 AM by Chelsey H

Genome editing could provide a powerful new way to study complex brain disorders. The breakthrough use of a genome-tool to create two monkeys with specific genetic mutations demonstrates that the ability to modify targeted genes in primates is a valuable tool in the study of human diseases.

This breakthrough took place last November in Kunming, the capital of China's southwestern Yunnan province. Scientists used a new method of DNA engineering known as CRISPR, to modify fertilized macaque monkey eggs by editing three different genes. The eggs were then implanted into a surrogate macaque mother. Twin females were born in the Yunnan Key Laboratory of Primate Biomedical Research and it was the first time that CRISPR has been used to target genetic modification in primates.

Credits: illustrations by John Macneill

CRISPR was originally developed by researchers in California and Boston over the last several years. It is a breakthrough technology because it allows scientists to make changes to the genome precisely and relatively easily. "The idea that we can modify primates easily with this technology is powerful," says Jennifer Doudna, a professor of molecular and cell biology at the University of California, Berkeley, and a developer of CRISPR.

This breakthrough could lead to powerful new ways to study complex human diseases; however is also poses new ethical dilemmas since the technology could ultimately alter fertilized human eggs to create genetically modified babies (aka "designer babies").

This thought is far removed from the minds of scientists working on CRISPR. They see the potential opportunities to create animals with mutations linked to human disorders, including brain disorders. Many brain disorders, such as autism, schizophrenia, and Alzheimer's disease, are difficult to study in mice. Often times, the psychiatric drugs that appear to work well in mice have not proved successful in human trails and many pharmaceutical companies have scaled back efforts to develop treatments. Therefore, using primates as models for such diseases could be helpful to researchers as a way to identify mutations.

Weizhi Ji, who helped lead the effort -, says the Chinese researchers responsible for the birth of the genetically engineered monkeys are still focusing on developing the technology. He goes on to say that considering the dangers, there would be a long way to go before creating humans with CRISPR-edited genomes is possible. Right now, they hope to use the technology to create "efficient animal models for human diseases to improve human health in the future."

Genome Editing

This story is part of a series of 10 Breakthrough Technologies 2014 on MIT Technology Review.

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Wearable Tech To Improve Your Health

Posted May 24, 2014 12:00 AM by Chelsey H

I'm a sucker for cool gadgets and even more so for gadgets that help me track my life. I've been on a health kick lately, and my UP band has been instrumental in keeping me moving (and sleeping) every day.

There are several fitness bands on the market, and I've heard good things about the Fitbit,.but I am currently using the UP by Jawbone. I like it because it's discrete (even stylish) and the information provided by the app is detailed and easy to understand. The UP by Jawbone V2 costs around $100 and is packed with an accelerometer, vibrating motor, and 10 days' worth of battery life before it needs to be recharged. It doesn't have a display other than a few LEDs which indicate what mode the band is in, and it connects to an app through the headphone jack.

It's meant to be worn all day (except when showering or swimming). One of my favorite functions of the UP band is that it can wake you in the morning with a gentle vibration when it senses you're in a light stage of sleep. Another of my favorite features is that is can be connected with workout apps like RunKeeper and MyFitnessPal, so you can see your activity and calorie intake all in one place. But the UP app itself is great! You're able to set goals like how many steps you should take per day and how many hours of sleep per night.

The idea behind the various wearable activity-tracking bands is, generally, to collect a great deal of information about your sleep and activity that you wouldn't otherwise know or have collected in one place. The goal is to give users a gentle nudge to improve their fitness and well-being.

Jeremiah Robison, head of Jawbone's software, is trying to figure out even better ways to prod people. According to an article on Technology Review, this past Thanksgiving-a day when people are less active than normal-Jawbone ran a test with two groups of people who wear UP bands: it left some alone, while it politely manipulated others on the smartphone app by reminding them of their regular daily goal for exercise. Robison says people who received the challenge logged 40 percent more steps.

There are newer versions of the UP band on the market or coming out soon that will be to sync and control more. For example, the newest version of the UP band, UP24, can sync with the thermostat so your house knows when you're home and will adjust the temperature accordingly. It's all in an effort to make this wearable technology more responsive to your needs.

For now, I'm content with seeing how many steps I take per day. It certainly is motivating to try to reach my goal of 10,000!

Do you have a fitness band? Do you think there is a benefit to your health in tracking this information?

9 comments; last comment on 05/30/2014
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Brain Mapping - New Breakthrough Technology

Posted May 11, 2014 5:59 PM by Chelsey H

Brain mapping still sounds like something in a science fiction movie to me, but it has been listed on Technology Review's 10 Breakthrough Technologies 2014. Amazingly accurate brain maps are in fact real.

Neuroscientists try to understand how the brain works on a detailed level. The newest breakthrough in achieving this goal is a high-resolution map that shows tiny structures of the human brain.

This breakthrough, part of Europe's Human Brain Project, took a decade to complete. The international team of researchers sliced a brain into thousands of thin slices and digitally stitched them back together with the help of supercomputers. The process allows the scientists to show details as small as 20 micrometers, roughly the size of many human cells. It is a major step forward in understanding the brain's three-dimensional anatomy.

The team of researchers, led by Katrin Amunts at the J├╝lich Research Centre in Germany, used an MRI machine to image the postmortem brain of a 65 year-old women. The brain was then cut into ultrathin slices. The slices were stained and imaged on a flatbed scanner resulting in a total of 7,404 images. Alan Evans and his coworkers at the Montreal Neurological Institute corrected any defects in the images and aligned each one to its original position in the brain. The final image was a brain model that can be used to scrutinize arrangements of cells and tissues.

In the future, further advances may allow scientists to see the arrangement of cells and nerve fibers inside intact brain tissue at very high resolution. Several techniques are already being developed but the challenges are many. Some of the obstacles include the brain tissue itself: the brain can only be sliced so thin before it becomes too damaged to work with. Another challenge is the large amounts of data associated with additional high resolution images, as computers today can't easily navigate such quantities.

Still, this work is an amazing breakthrough for neuroscientists to better understand how the brain works by studying the anatomy of a brain on a cellular level.


Brain Mapping

12 comments; last comment on 05/12/2014
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Coffee Helping with Hydration?

Posted March 24, 2014 12:00 AM by Chelsey H
Pathfinder Tags: coffee hydration. drinking Water

We talk a lot about coffee on CR4. Maybe it's because there are always new studies discussing the benefits of the drink or maybe it's because we like to talk about what we know….and on CR4, we know coffee. But did you know that coffee may actually help with hydration?

A study released by the University of Birmingham in the U.K. focused on busting the myth that coffee causes dehydration. Fifty male coffee drinkers (habitually consuming 3-6 cups per day) participated in two trials during which all physical activity, as well as food and fluid intake was controlled. Participants consumed either 4x200mL of coffee or water and total body water was calculated pre- and post- trial. At the end of the trial there were no significant changes (or differences) in total body water, urine volume, or body mass measurement. Image Credit

The study shows that caffeine has no influence on hydration status. According to Douglas Casa of the University of Connecticut, the coffee didn't "prompt the body to pee (or flush out) more fluid."

According to Sophie Killer, a doctoral research at Birmingham, "It's well understood that if you drink coffee habitually you can develop a tolerance to the potential diuretic effects of coffee". And for that I am grateful because as much as I try to increase the amount of water I drink, it's still easier to opt for coffee as a delicious afternoon pick-me-up.

Now this isn't an excuse to substitute all water for coffee, since too much coffee can lead to jitters and plain water has some pretty amazing health benefits; but, a daily coffee habit won't lead to dehydration.

Another interesting fact is that most people lose their tolerance after 4 days without coffee.

Do you have a coffee tolerance? Do you know of any other benefits of drinking coffee?

16 comments; last comment on 04/21/2014
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Daylight Savings Time and You

Posted March 16, 2014 10:00 AM by Chelsey H
Pathfinder Tags: Daylight saving time DST sleep

On a Sunday every March and every November at 2 a.m. clocks around the world are changed for what seems like no good reason. I always remember it as "Spring forward, Fall back".

Daylight saving time (DST) was enacted in the U.S. during World War I as a way to decrease energy use since people would go to bed earlier when it was dark out and wake up earlier as it got lighter earlier.

While there is still some debate as to whether or not it actually saves energy (with a strong vote towards the negative) there is evidence that the time-switch has negative health effects. Perhaps the most obvious is that it affects people's sleeping patterns. An earlier "bed-time" means people are restless at night and therefore tired during the day, decreasing productivity. Even more troubling, during the first week of DST (in the late winter) there is a spike in heart attacks, according to a study in the American Journal of Cardiology. According to the study, this is because losing an hour of sleep increases stress and provides less time to recover at night. Heart attacks decrease at the end of daylight saving time (when we gain the hour back). Image Credit

DST has also been linked to an increase in deadly car crashes and accidents at work. Cognitive effects have been observed as well; a 2011 study in Journal of Neuroscience, Psychology, and Economics found that students in counties where DST was observed had SAT scores 2 percent lower than those of students who didn't have to spring forward or fall back. I officially have a new excuse for my SAT scores.

All of these effects can be attributed to our body's internal circadian rhythm. This molecular cycle is responsible for regulating when we feel awake and when we are tired, as well as hunger and hormone production schedules. Since DST is ultimately effecting how much light we get, our natural clocks go out of whack. The feeling is similar to being jet lagged. Image Credit

But it's tough to say who DST is actually benefitting.

DST has been shown to increase residential electricity demand (especially in the fall when heating costs increase) and decrease work force productivity, but retailers and the golfing industry love the extra sunlight!

Supporters of DST claim that the extra hour in the summer reduces the amount of television watched and increases outside activities like jogging and walking. However, being off of your circadian rhythm can increase the risk of obesity, sleep disorders, diabetes, and even mental health issues.

Most people do adjust to the change in a couple of days; for night owls and those who are chronically sleep deprived (guilty) it can take a full week to catch up.

Now that you've had a week to adjust, what do you think about DST?


Daylight Saving Time is Bad for Your Health

Daylight Saving Time: Bad for Your Health, Not Good for Much Else

Is tinkering with time bad for your health?

Daylight Saving Time 2014: When Does It Begin? And Why?

16 comments; last comment on 03/18/2014
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