Many people have long   dreamed of being able to fly around as simply as riding a bicycle.

Yet the safety and strength of a flying bike was always a big problem. Over the past 10 years’ developments in technology have moved the dream of personal flying vehicle closer to reality. Now, two groups of inventors say such vehicles may be available very soon .

Grant Stapleton from Malloy Aeronautics says the Hoverbike, which is able to get in and out of small spaces very quickly, will be a truly personal flying vehicle. " It can be moved across continents very quickly because it can be folded and packed, " he adds.

Mr. Stapleton says safety was the company's main concern when developing the Hoverbike, He says the designers solved the safety issue by using overlapping rotors （折叠旋翼）to power the vehicle. The company is testing both a one-third size model and a full-size prototype （原型)）of the Hoverbike.

Inventors say their Hovebike will most likely be used first by the police and emergency rescue teams.

In New Zealand, the Martin Aircraft Company is also testing a full-size prototype of its personal flying bike, called Jetpack. It can fly for more than 30 minutes, up to 1,000 meters high and reach a speed of 74 kilometers per hour.

Peter Coker is the CEO of Martin Aircraft Company. He said Jetpack " is built around safety from the start ” In his words, reliability is the most important part of it. We have safety built into the actual structure itself very similar to a Formula One racing car."

Jetpack uses a gasoline-powered engine that produces two powerful jet streams. Mr. Coker says it also has a parachute （降落伞）that can be used should there be an emergency.

"It opens at a very low altitude and actually saves both the aircraft and the pilot in an emergency," he adds.

A special device (设备) worn on the head that sends electrical charges into the brain may improve the memory abilities of older people. The device may even give them the ability to remember things as well as a person 20 to 30 years younger than them. These are the findings of a study published in Nature Neuroscience earlier this month.

Researchers working on the study found that the age-related damage to working memory can be repaired. This is possible through stimulating (刺激) two important areas of the brain at a special rhythm. Working memory is the information held temporarily for use in immediate activities such as reasoning and decision-making.

42 younger adults aged 20 to 29 and 42 older adults aged 60 to 76 took part in the study. The researchers tested all subjects for their performance in a working memory activity. The findings are still early and only relate to healthy volunteers. But the findings could point to new ways to increase brain operation in older people suffering from diseases that affect these operations, such as dementia and Alzheimer’s patients.

Electroencephalography, or EEG, is a method of observing brain activity. Transcranial alternating current stimulation, or tACS, is the means of sending electrical charges into the brain. Using both EEG and tACS, the scientists stimulated the brains of the group of young and old people. They were able to make small changes to the brainwave connections linked to their working memory.

Without brain stimulation, the older people were slower and less correct in their memories than the younger ones. This was because the younger people had higher levels of connections of certain brain wave rhythms.

Robert Reinhart, a researcher at Boston University, said that when older adults received active brain stimulation, they improved their working-memory test scores to the levels of the younger people. The effect lasted for at least 50 minutes after the stimulation was given.

As a young child, Ann Makosinski would spend hours experimenting with her toys and other everyday objects ar ound her to create her own inventions.

Now a first-year Arts student, Makosinski is a well-known inventor. She won the recent Sustainable Entrepreneurship Award of Excellence, which recognizes creative business solutions to social problems--the same recognition was given to Barack Obama in 2014. Her two inventions—the Hollow Flashlight and the e-Drink—have been causing excitement internationally since their creation.

When Makosinski was 15 years old, she created a flashlight powered by the heat of one's hand. This invention was the result of a 9th grade science project, but her goal was to offer a practical solution to people with unlimited access to power and electricity. “One of my friends from the Philippines told me that she failed school because she had no light to study with at night, so that was kind of the inspiration.” Makosinski explained.

At 12th grade, Makosinski then went on to create the e-Drink. It is a coffee cup that harvests the extra heat of a hot drink while it cools, stores it as electricity in an internal(内置的)battery and makes it available to charge an external device such as a phone, whose life can now be longer by approximately 10 to 30 minutes.

“My favorite part of creating inventions would be when you had the idea and you have to physically build it，and it doesn't work out,” she said. “So you have to figure out different ways to solve it. A lot of times, I'll give up and I’ll come back after a couple of days and I'll take it up again.”

Her advice to other student innovators? “Start now. There’s nothing holding you back. Actually, you can do whatever you want.” Makosinski said，“If you want to make something，follow your heart, then go ahead. If there's something you really want to do, you will make time for it and you will find time in the day to do your   schoolwork.”