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Pseudomonas aeruginosa SEM

Scientists turn bacteria as an instrument for measuring fluid speeds

A group of researchers from Princeton University has detected bacteria which has the ability to find the speed of fluids in motion. There are many different types of cells which can sense flow similar to the skin cells in human beings. The research has been published in Nature journal.

Zemer Gitai, a biology professor and a senior author on the research paper of Princeton’s Edwin Grant Conklin University said that they have discovered that bacteria can also be used for detecting speed and also added that there’s an application where we can use the bacteria as a flow sensor and we can know the speed in real time. Pseudomonas aeruginosa is that bacteria which have a built-in speedometer.

Pseudomonas is the bacteria which is responsible for health issues and healthcare-related infections per year and this ubiquitous pathogen is found in and on the bodies, in the soil, in the streams of water and throughout the hospitals. This bacteria was found as a serious threat in the centre for disease control and prevention.

Gitai said that chemical disinfection is used instead of scrubbing in some hospitals since pseudomonas loves to grow in pipes. Pseudomonas is said to be surrounded by flowing fluids like the bloodstream, the urinary tract, the gastrointestinal tract as well as in the lungs or in plumbing systems or in medical equipment too like catheters which is one of the primary vectors used for post-surgical infections. Gitai also added that they have found something new about pseudomonas that they can also detect the flow and respond to it and they can change their attitude too.

A postdoctoral research associate in Gitai’s lab, Joseph Sanfilippo and a 2017 graduate alumnus Alexander Lorestani are the main authors on this paper. They together found out that the bacteria can detect the nearby flow of the genes too and those genes are known as fro which stands for flow-regulated operon. Sanfilippo said that fro is tuned as per the speed and it’s not just a switch to on and off but it’s more like a dimmer switch than a light switch.

The researchers created a link between the fro and gene so that they can see in the microscope and thus ended up creating visual speedometer and it is visualized using the light of the flow that is the brighter the glow the faster the flow and Gitai said that they found out something interesting that the speed range matched with the fluids present in the bloodstream of urinary tract.

The scientists found out that the rate of flow in average sized human veins are about 100 per second and they also found that the fro was not able to detect flows below 8 per second but it responded to the flow between 40 and 400 per-second and stay above that.

Speed of light measurement device

Scientists develop techniques to manipulate speed of light

A group of researchers at the University of Central Florida have developed a technique to be able to control the velocity of light. Through this technique they can not only increase the speed of light pulse and decrease it, but they can also make it travel backwards. The results were published in Nature Communications.

This finding is a significant step in the research which can someday lead to the development of highly efficient optical communication techniques. The problems of data congestion and information loss can also be handled with this result. Currently, networks use congestion control and congestion avoidance techniques to avoid these problems. More and more devices are going online everyday and advanced techniques like these will be of prime importance in the future. With fall in the prices of data consumption, people in developing countries are getting easier access to data like never before.

There have been many attempts in the past to control the speed of light. For example, light was passed through different media to adjust the speed. The major breakthrough in this experiment is that speed of light can be adjusted in the open for the first time, without using any pass-through media to increase or decrease its speed.

Ayman Abouraddy, professor in UCF’s College of Optics and Photonics who is also a co-author of this study remarked that this is the first clear demonstration of controlling the speed of the light and this will open up many areas of possibilities not explored before. This is done in a simple, reliable and repetitive way which is an important aspect.

Scientists could speed up the light upto 30 times of its normal speed, reduce to half of the speed of light and also make the pulse travel backwards. The researchers managed to develop the technique with the help of a special device called as the phase-only spatial light modulator (SLM). This helps to combine the space and time properties of light, thus making it possible to manipulate the velocity of light.

SLM was used to sculpt the spatio-temporal spectrum in an efficient manner and thus modify the group velocity. When the researchers manipulated the spatial and temporal degrees of freedom simultaneously, they found out that the group velocities were varying arbitrarily, sometimes more than the speed of light and sometimes less. They were also propagating in the forward direction away from the source and even travelling backward.

The mixing of the two main properties of light was essential to the success and scientists hope that these results can be used in a fruitful way in the future.