Screening tools to detect lung, heart disease developed by two high school students

Two Michigan high school students, sisters Ilina and Medha Krishen, have developed screening tools using electronic stethoscopes to detect lung and heart disease. The sisters will present their findings at CHEST 2014 in Austin, Texas next week. Credit: The Krishen family

Two Michigan high school students, sisters Ilina and Medha Krishen, have developed screening tools using electronic stethoscopes to detect lung and heart disease. The sisters will present their findings at CHEST 2014 in Austin, Texas next week.

Ilina Krishen became aware of the dangers of smoking and chemical air pollution when she saw the effects of lung disease on family members. Curious to find a way to detect early lung damage in people exposed to noxious air pollutants, Ilina, a high school senior at Port Huron Northern High School in Michigan, developed a screening mechanism using an electronic stethoscope. An electronic stethoscope overcomes the problem of low sound levels by electronically amplifying body sounds, using an electromagnetic diaphragm that captures the diaphragm movement as an electrical signal.

Ilina recruited 16 smokers, 13 firefighters, and 25 nonsmokers for her test. The electronic stethoscope recorded one breath cycle from each volunteer. Frequency peaks were used to analyze the frequency distribution of breath sounds. Differences of peaks above 125 Hz were analyzed.

Ilina found that the number of peaks was significantly higher in smokers and firefighters, even if the firefighters were nonsmokers. She realized that although firefighters wear protective masks when fighting fires, they often do not wear masks when making a second check of the building after the fire is out. "The firefighters are exposed to many poisonous chemicals that remain in the air after the fire has gone out," said Ilina. "Screening with an electronic stethoscope may be able to detect early changes in lung function in individuals without symptoms of lung disease."

Medha Krishen, Ilina's sister and a junior at Port Huron Northern High School, also presented a study that used an electronic stethoscope to screen student athletes for hypertrophic cardiomyopathy (HCM).

Medha studied 13 individuals: 10 with a normal cardiac sports physical and three with a diagnosis for HCM. Heart sounds were recorded in 5-second periods while the athletes were lying down, standing, and after exercise. Frequency peaks of a frequency amplitude plot were analyzed. Studies showed a significant difference in the distribution of frequency peaks in the two groups between the lying down position and after exercise. Normal athletes showed a lower percentage of peaks above 131 Hz after exercise, while the athletes at risk showed a rise in frequency peaks following exercise.

"When I was in fifth grade, a family friend died after exercise, and I always wanted to learn more about how to prevent something like that happening," said Medha. "My study analyzing heart sound frequencies may be a useful technique that school staff could use to screen for HCM."

The sisters are both athletes -- Ilina is a varsity tennis player, and Medha is an accomplished figure skater -- and they take a personal interest in the health of athletes. They are also nonsmokers and hope to encourage others not to smoke. After Ilina completed her study and showed her study subjects the results of her tests "two or three of the smokers have quit smoking, and that makes me feel good," says Ilina.

Source: American College of Chest Physicians

A smart fluorescent antenna for Wi-Fi applications

A charged argon gas in the fluorescent lamp emits Wi-Fi signals. Credit: Faculty of Electrical Engineering, Universiti Teknologi MARA

A new invention uses ionized gas in fluorescent light tubes to transmit Internet wireless frequency signals throughout a building with the aid of already existing electrical wiring.

Due to continuously evolving applications, the electronic communications industry requires high performance and speed efficient systems. However, the physical limitations of microwave devices limits further improvements in current technology. This predicament has led to growing interest in the use of plasma as a conductive element in microwave devices due to their unique and innovative properties, which corresponds with traditional metallic antennas.

Matter exists in four different states: solid, liquid, gas and plasma. Plasma is a type of gas in which the atoms are ionized -- they have both free negatively charged electrons and positively charged ions. These charged particles can be controlled by electromagnetic fields, allowing plasmas to be used as a controllable reactive gas.

This invention employs an ionized gas enclosed in a tube as the conducting element of an antenna. When the gas is electrically charged or ionized to plasma, it becomes conductive and allows radio frequency signals to be transmitted or received. When the gas is not ionized, the antenna element ceases to exit.

The invention features a smart fluorescent antenna with a 3G/3.75G/4G router for Wi-Fi applications. The antenna operates at the 2.4 GHz frequency band, which is suitable for Wi-Fi applications. A commercially available fluorescent tube, measuring 0.61 metres in length by 0.25 metres in diameter, is used as the plasma antenna. The gas inside the tube is a mixture of argon and mercury vapour, in the ratio 9:1. The tube is energized by a 240 V current, provided by a standard AC power supply. A glowing tube indicates that the gas inside the tube has been ionized to plasma and forms a plasma column. In this state, the plasma column becomes highly conductive and can be used as an antenna.

A coupling sleeve is positioned at the lower end of the tube, which is used to connect the plasma tube to the router. The function of the coupling sleeves is to store the electrical charge. When the gas inside the tube is sufficiently ionized into a plasma state, it becomes conductive and allows radio frequency signals to be transmitted or received.

Measurements indicate that the plasma antenna yields a return loss over 10 dB in the 2.23 GHz to 2.58 GHz frequency band. The antenna's ability to operate as either a transmitter or receiver in this particular frequency band was verified through a series of wireless transmission experiments.

The performance of this antenna was measured using the Wi-Fi Received Signal Strength 
Indicator (RSSI) technique. The product was tested for a month in the Universiti Teknologi MARA's High Frequency Antenna Laboratory. Our results show that the signal is stronger and more stable compared to others signals.

One advantage of this product is its low cost. The Wi-Fi signal can be transmitted into other rooms using only one router with a splitter cable. The fluorescent tube has dual functionality, thereby reducing the cost of buying additional antennas. Commercial antennas are made from metal elements while this invention uses plasma element as its source of material. Normal antennas can only transmit and receive radio frequencies, while this product not only can be used for transmitting and receiving radio frequency signals, but as a light emitting device as well.

Source: Universiti Teknologi MARA (UiTM)

Electric eels deliver taser-like shocks

News research has discovered that the electric eel delivers Taser-like shocks. Credit: Kenneth Catania, Vanderbilt University

The electric eel -- the scaleless Amazonian fish that can deliver an electrical jolt strong enough to knock down a full-grown horse -- possesses an electroshock system uncannily similar to a Taser.

That is the conclusion of a nine-month study of the way in which the electric eel uses high-voltage electrical discharges to locate and incapacitate its prey. The research was conducted by Vanderbilt University Stevenson Professor of Biological Sciences Kenneth Catania and is described in the article "The shocking predatory strike of the electric eel" published in the Dec. 5 issue of the journal Science.

People have known about electric fish for a long time. The ancient Egyptians used an electric marine ray to treat epilepsy. Michael Faraday used eels to investigate the nature of electricity and eel anatomy helped inspire Volta to create the first battery. Biologists have determined that a six-foot electric eel can generate about 600 volts of electricity -- five times that of a U.S. electrical outlet. This summer scientists at the University of Wisconsin-Madison announced that they had sequenced the complete electric eel genome.

Until now, however, no one had figured out how the eel's electroshock system actually worked. In order to do so, Catania equipped a large aquarium with a system that can detect the eel's electric signals and obtained several eels, ranging up to four feet in length.

As he began observing the eels' behavior, the biologist discovered that their movements are incredibly fast. They can strike and swallow a worm or small fish in about a tenth of a second. So Catania rigged up a high-speed video system that ran at a thousand frames per second so he could study the eel's actions in slow motion.

Catania recorded three different kinds of electrical discharges from the eels: low-voltage pulses for sensing their environment; short sequences of two or three high-voltage millisecond pulses (called doublets or triplets) given off while hunting; and volleys of high-voltage, high-frequency pulses when capturing prey or defending themselves from attack.

He found that the eel begins its attack on free-swimming prey with a high-frequency volley of high-voltage pulses about 10 to 15 milliseconds before it strikes. In the high-speed video, it became apparent that the fish were completely immobilized within three to four milliseconds after the volley hit them. The paralysis was temporary: If the eel didn't immediately capture a fish, it normally regained its mobility after a short period and swam away.

"It's amazing. The eel can totally inactivate its prey in just three milliseconds. The fish are completely paralyzed," said Catania.

These observations raised an obvious question: How do the eels do it? For that, there was no clear answer in the scientific literature.

"I have some friends in law enforcement, so I was familiar with how a Taser works," said Catania. "And I was struck by the similarity between the eel's volley and a Taser discharge. A Taser delivers 19 high-voltage pulses per second while the electric eel produces 400 pulses per second."

The Taser works by overwhelming the nerves that control the muscles in the target's body, causing the muscles to involuntarily contract. To determine if the eel's electrical discharge had the same effect, Catania walled off part of the aquarium with an electrically permeable barrier. He placed a pithed fish on other side of the barrier from the eel and then fed the eel some earthworms, which triggered its electrical volleys. The volleys that passed through the barrier and struck the fish produced strong muscle contractions.

To determine whether the discharges were acting on the prey's motor neurons -- the nerves that control the muscles -- or on the muscles themselves, he placed two pithed fish behind the barrier: one injected with saline solution and other injected with curare, a paralytic agent that targets the nervous system. The muscles of the fish with the saline continued to contract in response to the eel's electrical discharges but the muscle contractions in the fish given the curare disappeared as the drug took effect. This demonstrated that the eel's electrical discharges were acting through the motor neurons just like Taser discharges.

Next Catania turned his attention to the way in which the eel uses electrical signals for hunting. The eel is nocturnal and doesn't have very good eyesight. So it needs other ways to detect hidden prey.

The biologist determined that the closely space doublets and triplets that the eel emits correspond to the electric signal that motor neurons send to muscles to produce an extremely rapid contraction.

"Normally, you or I or any other animal can't cause all of the muscles in our body to contract at the same time. However, that is just what the eel can cause with this signal," Catania said.
Putting together the fact that the eels are extremely sensitive to water movements with the fact that the whole-body muscle contraction causes the prey's body to twitch, creating water movements that the eel can sense, Catania concluded that the eel is using these signals to locate hidden prey.

To test this hypothesis, Catania connected a pithed fish to a stimulator.. He put the fish in a clear plastic bag to protect it from the eel's emissions. He found that when he stimulated the fish to twitch right after the eel emitted one of its signals, the eel would attack. But, when the fish failed to respond to its signal, the eel did not attack. The result supports the idea that the eel uses its electroshock system to force its prey to reveal their location.

"If you take a step back and think about it, what the eel can do is extremely remarkable," said Catania. "It can use its electrical system to take remote control of its prey's body. If a fish is hiding nearby, the eel can force it to twitch, giving away its location, and if the eel is ready to capture a fish, it can paralyze it so it can't escape."

The research was funded by a Pradel Award from the National Academy of Sciences, a Guggenheim fellowship and National Science Foundation grant 0844743.

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Source: Vanderbilt University