Holding the large and heavy "brick" cellphone he's credited with inventing 50 years ago, Martin Cooper talks about the future.

Little did he know when he made the first call on a New York City street from a heavy Motorola prototype(原型) that our world would come to be encapsulated on a sleek glass sheath where we search, connect, like and buy.

Cooper says he is an optimist. He believes that advances in mobile technology will continue to transform lives but he is worried about risks smartphones pose to privacy and young people.

"My most negative opinion is we don't have any privacy anymore because everything about us is now recorded someplace and accessible to somebody who has enough intense desire to get it," the 94-year-old said in an interview in Barcelona at MWC, the Mobile World Congress, the world's biggest wireless trade show, where he was getting a lifetime award.

Cooper sees a dark side to the advances, including the risk to children. One idea, he said, is to have "various Internets intended for different audiences."

Cooper made the first public call from a handheld portable telephone on a Manhattan street on April 3,1973, using a prototype device his team at Motorola had started designing just five months earlier.

Cooper used the Dyna-TAC phone to famously call his opponent at Bell Labs, owned by AT&T. It was literally the world's first brick phone, weighing 2.5 pounds and measuring 11 inches.

Cooper spent the best part of the next decade working to bring a commercial version of the device to market.

The call helped kick-start the cellphone revolution (革命).

Cooper said he's "not crazy" about the shape of modern smartphones. He thinks they will develop so that they'll be "distributed on your body," possibly as sensors "measuring your health at all times."

Batteries, he said, might be replaced by human energy. The body makes energy from food, he argues, so it could possibly also power a phone. Instead of holding the phone in the hand, for example, the device could be placed under the skin.

Concrete has served as the foundation stone of the construction industry for hundreds of years. However, the process of producing concrete is one of the most environmentally unfriendly processes in the world. In the process, not only is carbon dioxide（二氧化碳）released into the air by the energy used to heat the limestone, but the limestone itself also gives out a huge amount of the element. 

Luckily, a number of start-ups throughout the world are using creative thinking to make the construction industry a whole lot more friendly for the planet. 

A Canadian company called CarbonCure, has found a way to inject（注入）concrete with carbon dioxide itself. Not only does this trap the carbon dioxide into the concrete, keeping it from running away into the atmosphere, but it also creates a super strong material called calcium carbonate, which reduces the total amount of concrete that needs to be used. 

California-based Brimstone, is creating carbon-negative concrete by doing away with limestone entirely and instead using silicate rock, a material that does not release carbon dioxide when heated. Instead, the process produces magnesium（镁）, which absorbs carbon dioxide, as the basis for their concrete. 

Additionally, researchers at Australia's RMIT University have recently released a study showing that adding coffee grounds instead of sand to concrete could make it much stronger, reducing both the amount of sand used, as well as the amount of concrete that would need to be used in the final product. 

The biggest barrier at this point is convincing members of the industry that the new types of concrete are safe to be used, according to Stacy Smedley, director at a nonprofit focused on decarbonizing construction. 

Hopefully these new solutions to the environmental problems of concrete will soon be widely adopted. Given the significant part the construction industry has in releasing carbon dioxide into the atmosphere, great improvements can be made when more environmentally-friendly materials are used. 

This International Women's Day, we're celebrating four women who changed the face of science forever.

Anandibai Joshee, born in 1865 in India, became India's first woman physician with a medical degree. After graduation from a Woman's Medical College, she accepted an offer from the governor minister of Kolhapur in India to serve as "Lady Doctor of Kolhapur". She died at 21 from tuberculosis. Despite her short life, Joshee's accomplishments were unprecedented for an Indian woman, and her achievements open the door for other Indian women to quickly follow.

Mamie Clark, an American social psychologist, specialized in child development in black children. In 1946, Clark and Kenneth founded the only mental health organization for black children in New York. Clark was awarded the American Association of University achievement award in 1973, and ten years later the National Coalition of 100 Black Women awarded her the Candace Award for humanitarianism.

Geochemist Katsuko Saruhashi was born in Tokyo in 1920. Saruhashi became the first woman elected to the Science Council of Japan, the first woman to win the Miyake Prize for Geochemistry, and the first woman recipient of an award from the Society of Sea Water Science in Japan. In 1981, she founded the Saruhashi Prize, a prize awarded annually to a female role model in science.

Born in Los Angeles, California, Ochoa was the first Latina woman to fly in space as part of the crew of the shuttle Discovery in 1993. In 1990, Ochoa was selected to astronaut candidacy as part of a group of twenty-three NASA astronauts, and became an astronaut a year later. Her first spaceflight was aboard Discovery as a mission specialist and lasted nine days, in which the crew conducted scientific experiments and deployed a research satellite to study the solar corona.