阅读理解

    Life-Changing Science Discoveries

    Here's a look at some discoveries that have changed the world. It's impossible to rank their importance, so they're listed in the order they were discovered

Micro-organism

    Before French chemist Louis Pasteur began experimenting with bacteria in the 1860s, people did not know what caused disease. He not only discovered that disease came from micro-organisms, but also realized that bacteria could be killed by heat and disinfectant(消毒剂). This idea caused doctors to wash their hands and disinfect their instruments, which has saved millions of lives.

Penicillin

    Antibiotics are powerful drugs that kill dangerous bacteria in our bodies that make us sick. In 1928, British Alexander Fleming discovered the first antibiotic, penicillin, which he grew in his lab. Without antibiotics, infections like strep throat could be deadly

DNA

    On February 28, 1853, James Watson of the United States and Francis Crick of England made one of the greatest scientific discoveries in history. The two scientists found the structure of DNA. Our genes are made of DNA and determine how things like what color hair and eye we'll have. In 1962, they were awarded the Nobel Prize for this work . The discovery has helped doctors understand diseases and may someday prevent some illnesses like heart disease and cancer.

X-rays

    Wilhelm Roentgen, a German physicist, discovered X-rays in 1895. X-rays go right through some substances, like flesh and wood, but are stopped by others, such as bones and lead. This allows them to be used to see broken bones or explosives inside suitcases, which makes them useful for doctors and security officers. For this discovery, Roentgen was awarded the first-ever Nobel Prize in Physics in 1901.

    US scientists say they have poured cold water on the theory that washing hands with hot water kills more germs (细菌) than unheated water. The small study of 20 people found using water at 15C (59F) left hands as clean as water heated to 38C (100F).

    National Health Service (NHS) recommends that people wash their hands in either cold or warm water. In this study, scientists at Rutgers University-New Brunswick wanted to find out if popular assumptions about the benefits of warm or hot water and official guidance on hot water — given to the food industry in the US — held true. They asked 20 people to wash their hands 20 times each with water that was 15C (59F), 26C (79F) or 38 degrees (100F). Volunteers were also asked to experiment with varying amounts of soap. Before they started the tests, their hands were covered in harmless bugs. Researchers say there was no difference in the amount of bugs removed as the temperature of the water or the amount of soap changed.

    Prof Donald Schaffner said: “People need to feel comfortable when they are washing their hands but as far as effectiveness goes, this study shows us that the temperature of the water used did not matter.”

    However, the researchers accept their study is small and say more extensive work is needed to determine the best ways to remove harmful bacteria.

    In the UK, NHS experts say people can use cold or hot water to wash their hands. They say hands should be washed for at least 20 seconds and stress the importance of using enough soap to cover the whole surface of the hands. Their guidance focuses on rubbing hands together in various ways to make sure each surface of each hand is clean.

    The city of San Francisco is a wonderful tourist attraction that offers many different things to see and do. The best way for a traveler to get a good look at the city is to take one of the many different tours there

    Walk to Tour the City

    When touring the city by walking, you aren't going to walk much. What's more, there are far more benefits. This kind of tour allows you to see as many buildings of the city as possible. A tour of the city on foot usually focuses on a more localized neighborhood level, which can be very interesting in a number of different ways.

    Hit the Waters of San Francisco Bay

    The waters of San Francisco Bay have played an important role in the city's development over the last century. Touring San Francisco from the water is completely unique way for you to see this wonderful city.

    Take a Bus Tour

    If you want to see a wide variety of attractions from all over the city, one of the best things you could do is to book a tour through our company that offers services here. A bus tour of San Francisco is one of the most complete ways to experience the city

    Tour San Francisco From the Air

    While it is one of the most expensive ways to see San Francisco, touring the city from the air is one of the most unique and exciting ways to see the city. Seeing the city from high above allows you to get a full view of the city as tour guides point out attractions from high above. If you do decide to tour San Francisco by air, you'll be creating memories that you won't forget forever.

    We are a travel agency providing high-quality services and discounts. For more information, please click here.

Tests have shown robots can diagnose heart problems in as little as four seconds, as a review of artificial intelligence (AI) finds machines are now as good at spotting illness as doctors.

Analyzing a patient's heart function on a cardiac MRI (心脏磁共振成像) scan currently takes doctors around 13 minutes. But a new trial by University College London (UCL) showed an AI program could read the scans in less time with equal accuracy. There are approximately 150,000 such scans performed in the UK each year, and researchers estimate that fully using AI to read them could save 54 clinician-days (临床天数) at each cardiac centre per year. So it can make up for the shortage of doctors.

It is hoped that AI where computer systems are able to learn from data to identify new patterns with minimal human intervention will transform medicine by helping doctors spot diseases such as heart disease and cancer faster and earlier. However, most scans are still read by specially trained doctors.

Dr Charlotte Manisty, who led the UCL research, said, "Cardiovascular MRI offers in- comparable image quality for assessing heart structure and function. However, current manual analysis remains basic and outdated. Automated machine techniques offer the potential to change this and completely improve efficiency and accuracy, and we look forward to further research that could confirm the superiority to human analysis."

She added, "Our dataset of patients with a range of heart disease who received scans enabled us to demonstrate that the greatest sources of measurement errors arise from human factors. This indicates that automated techniques are at least as good as humans, with the potential soon to be 'super-human'—transforming clinical and research measurement precision."

Professor Alastair Denniston said, "Within those handful of high-quality studies, we found that by deep learning AI could indeed detect disease ranging from cancer to eye disease as accurately as health professionals. But it's important to note that it did not absolutely exceed human professional diagnosis. "

Accines (疫苗) may soon make their first film appearance. Led by expert Maria A. Croyle, researchers have developed a thin sheet that preserves vaccines for long periods without refrigeration. This means the carefully cooled small bottles now used to ship vaccines could potentially be replaced by lightweight films that can be mailed in an envelope and stored on a shelf.

Croyle's laboratory began developing the technology in 2007. Inspired by amber's ability to preserve the DNA of insects, the researchers set out to create their own version of the substance by mixing "a lot of sugar and a little bit of salt, much like hard candy," Croyle explains. The vaccine-containing film is administered by mouth—sweet news for many who dislike needles.

The film is tailored to suit each specific vaccine candidate and provide a protective coating. "We've learned over time that the key to really stabilizing whatever the film holds is to have it intermixed with all the components," Croyle says, adding that the process is quick and uses affordable, standard equipment. "We really wanted to come up with something that would be transferable to developing countries."

Immunization(免疫) programs depend heavily on keeping vaccines cold(2℃-8℃) as they are transported, sometimes over thousands of kilometers to far-away locations. Delivery can be difficult and costly, and transport disruptions can cause the vaccines to be ineffective.

But this new product can store live viruses, bacteria and antibodies for several months at 20℃. In a paper published in Science Advances, the scientists show that the live viruses in one vaccine were preserved in the film even after 36 months. They also find that a flu vaccine suspended in their film compares favourably with a traditional flu shot(流感预防针). "The study demonstrates early proof of concept for an exciting platform for vaccine product development," says Lisa Rohan, a pharmacologist, who was not involved in the study. She also notes that each vaccine type would need a custom formulation(配方) for future stages of development.

Finding partners to mass-produce for clinical trials is the researchers' most pressing problem, Croyle says. They are also exploring packaging methods to keep their films stable up to 40℃.

Size is a major advantage—a letter-sized sheet of the film can carry more than 500 doses(剂) of vaccine, about 1⁄900 the weight of the same amount of traditional doses. By making it easier and cheaper to ship and preserve vaccines efficiently, Croyle says, the technology could vastly improve immunization rates the world over, particularly in middle- to low- income countries.