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Thinking in the Bubble:   How to Detect Land Mines

By Shlomo Maital

Writing in the Hebrew daily Haaretz, today, Ruth Schuster reports on a clever creative invention by Hebrew University scientists.

   The problem: undetected land mines.

   “Land mines are the scourge of the survivor. They lurk in the soil for years and even generations after the fighting ends. Up to 20,000 people a year are wounded or killed after stumbling on hidden mines, and there has been no safe way for man or beast to detect them. According to Hebrew University, more than 100 million land mines remain buried around the world. Metal detectors do fine with traditional mines, but plastic ones elude them.”

A huge number of ideas to detect and clear mines have been tried. Here are a few:

Mine detection techniques have remained as pedestrian as they were in World War II: soldiers with sticks and serendipity; dogs, who do get killed; and pigs (a talent discovered by a kibbutznik in Israel). The most noteworthy advance in decades had been recognizing the mine-sniffing talents of the African pouched rat.

Now come Hebrew University of Jerusalem scientists, with a truly creative idea, thinking out of the box, or in the bubble or beads:   Bubbles with bacteria that glow blue when they detect vapors emitted by land mines.. even tiny amounts of the gas, and all mines emit such vapors.

       “Inspired by an idea that was first conceptualized in 1999, the scientists engineered   bacteria that fluoresce when they come into contact with these vapors. The human mine detectors don’t have to keep the bacteria on a leash: they can monitor and react remotely. Nor are the bacteria free-range: they are encapsulated in beads that are scattered across the suspect land. The scientists tested the system with a laser-based scanning system, and the mines were found.”

     Prof. Shimshon Belkin was responsible for genetically engineering the bacterial sensors.   The research was published recently in the leading journal Nature.

The World’s Most Incredible Invention

By Shlomo Maital   


Thanks to an outstanding BBC World Service program, “Discovery”, I have new appreciation for what must be the greatest invention ever:  Nature’s invention of photosynthesis, as a lucky accident through evolution.

   The word itself comes from two Greek roots meaning “light” (phos) and “putting together” (“synthesis”).  Plants use light energy from the sun, together with water and carbon dioxide, to produce two vital things:  carbohydrates, e.g. glucose, and oxygen.  The process is mediated and catalyzed by green chlorophyll.  What happens is:  six carbon dioxide molecules combine with six water molecules, using solar energy aided by chlorophyll, to make one glucose molecule and six oxygen molecules:

     6CO2 +    6H2O  =    C6H12O6 +   6O2  

     Photosynthesis does two things for life on earth: It provides all the organic compounds, and most of the food energy needed for life,   and it maintains atmospheric oxygen levels.  

   The rate at which photosynthesis captures solar energy is incredible:  130 terawatts, which is six times greater than the total power consumption of the human race

   We humans are incredibly arrogant.  But to date, we have nothing that comes close to photosynthesis, as a way of capturing solar energy and storing it as food energy.  Photovoltaic cells are a joke in comparison.  If we humans could store energy as plants can, we could produce power at night, when usage is nil, and use it during the day, thus almost halving our daytime production capacity.  But we can’t.  Only Nature can. 

   And just think – photosynthesis originated as an accident of evolution, one that just happened to work nicely, and that made possible life on earth. 

   Now, THAT’s an innovation!

Blog entries written by Prof. Shlomo Maital

Shlomo Maital
April 2017
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