Quicker and faster 3-D printers have allowed not just amazing objects to be created, but have started to affect how doctors treat patients.

    We've put together a list of some of the most amazingmedical break throughs made possible with 3-D printing.

Life-Saving Airway

    In 2013, doctors created a new airway for kaiba Gionfriddo, aboy born with an airway that kept collapsing (萎陷). To save his life doctors printed tiny tubes to join together in different shapes and sizes until one finally worked for Kaiba. It was placed in Kaiba's bronchus (支气管) so that it no longer collapsed. Even more remarkably, once the plant was placed it couldstay there. It's designed to eventually be absorbed into the body.

New “Bionic” Hands

    One of the most remarkable ways 3-D printing is now being used is as a way to create prosthetics (假肢). A boy born without an arm named Alex was able to get a new“bionic”hand thanks to it. Last year a college student spent 8 weeks coming up with a special prosthetic design that only cost a few hundred dollars in materials. He said he wanted to create a prosthetic far cheaper than other choices that can run tens of thousands of dollars.

A practice Heart

    In Seattle, doctors have been able to use 3-D printing technology to“practice”risky operations so that they will face fewer surprises in the operating room. Kami Sutton was born with her heart“in the wrong place”. For a recent operation her doctor was able to take many scans of Sutton's heart and print out a model. “Kami's heart is truly one-of-a-kind,”Dr. Stephan Seslar, a heart disease specialist said. “Operating on her without understanding the structure of her heart better could be very dangerous.”

A New Skull

    A U.K. man was able to have part of his skull rebuilt thanks toa 3-D printer. Stephen Power broke his cheek bones in a crash. To help Powerh is doctors instead created 3-D bones all carefully printed in the shape of his face. “This is really the first time we've taken it to this stage, where everything has been planned and modeled in advance — and worked sweetly,”said Adrian Sugar, a doctor.

"Over the years the unthinkable hasbecome thinkable and today we sense we are close to being able to alter humanheredity œ#)." These were the words of David Baltimore of the CaliforniaInstitute of Technology, on December 1st, when he opened a three-day meeting inWashington to discuss the morality and use of human gene editing. Dr Baltimoreis an old hand at these sorts of discussions, for he was also a participant inthe Asilomar conference, in 1975, which brought scientists together to discussa safe way of using the then-new tcchnology of recombinant DNA, and whoserecommendations influenced a generation of biotechnology researchers.

Four decades on, the need for a similarsort of chin-wag has arisen. The InternationalSummit on Human Gene Editing has been held by the national scientific academiesof three countries — America, Britain and China. They are particularlyconcerned about whether gene editing should be used to make heritable changesto the human germ line, something Dr Baltimore described as a deep andtroubling question. Like those of Asilomar, the conclusions of this meetingwill not be binding. But the hope is that, again like Asilomar, a mixture ofcommon sense and peer pressure will create a world in which scientists aretrusted to regulate themselves, rather than having politicians and civilservants do it for them. The meeting is being held against a backdrop of rapidscientific advance, Since 2012 research into a new, easy-to-use editing tool calledCRISPR-Cas9 has blossomed. This technique involves a piece of RNA (a chemicalmessenger, which can be used to recognise a target section of DNA) and anenzyme (酶)called a nuclease that can snip unwanted genes out and paste new ones in.

Public interest was aroused in April,when Chinese scientists announced they had edited genes in non-viable ( 无活力的) humanembryos, and again in November when British researchers said they hadsuccessfully treated a one-year-old girl who had leukaemia ( 白血病),using gene-edited T-cells. T-cells are part of the immune system that attack,among other things, tumour cells. The researchers altered T-cells from ahealthy donor to encourage them to recognise and kill the patient's cancer, tomake them immune to her leukaemia drug, and to ensure they did not attack herhealthy cells.

In another recent development, a firmcalled Edit as Medicine, which is based in Cambridge, Massachusetts, has saidit hopes, in 2017, to start human clinical trials of CRISPR-Cas9 as a treatmentfor a rare genetic form of blindness known as Leber congenital amaurosis (伯氏先天性黑蒙).Though other companies are already testing gene-editing therapies, these employolder, clunkier forms of the technology that seem likely to have lesscommercial potential. Moreover, researchers at the Broad Institute, also inCambridge, said this week that they had made changes to CRISPR-Cas9 whichgreatly reduce the rate of editing errors — one of the main obstacles to thetechnique's medical use.

On the subject of germ-line editing,Eric Lander, the Broad's head, told the meeting it would be useful only in rarecases and said it might be a good idea to "exercise caution? before makingpermanent changes to the gene pool. The need for caution is advice that mightalso be heeded by those pursuing work in animals other than people, and inplants — subjects not being covered by the summit.

    After the sudden loss of her 5-year-old daughter, Elizabeth, Natalia Spencer felt she needed to do something to honor the little girl. That strong wish inspired Spencer to start what she calls a “Walk of Love”, a 6,000-mile trek (长途徒步旅行）along the British coastline.

    “Elizabeth particularly loved the beach and the sea and we visited the seaside a lot. After she passed away, I went to the seaside and it was the first time I had felt some comfort,” Spencer said. “I knew this was what I had to do. It was something I could do and it would somehow make life more bearable.”

    On Valentine's Day, Spencer began walking Durdle Door in Dorset, England, the last beach she took Elizabeth to before she became ill. So far, Spencer has journeyed about 1,500 miles, walking through Dorset, Cornwall, Devon and the entire coast of Wales. Every day, except Saturday, Spencer walks 20 miles. Often locals join her; many times they share stories about losing their own children.

    Everything changed for Spencer on Nov. 22, 2015. Spencer noticed Elizabeth was ill with what she thought—was a chest infection. But the girl's health worsened rapidly. Doctors diagnosed her with a life-threatening immune condition where the immune cells damage tissue and organ. This caused Elizabeth's organs to shut down and stopped the blood supply to her arms and legs. She was moved to Bristol Children's Hospital where she spent 18 days on life support before passing away on Dec. 10.

    After Elizabeth died, Spencer struggled. She stayed with friends because it felt too hard to live in a house with the memories of Elizabeth. In January, a friend encouraged Spencer to go for a walk and the two ended up at the Gower Peninsula in Wales. That's when she realized she wanted to walk along the coast for her daughter.

    While walking provides Spencer with time to grieve (感到悲痛)，she's also using the trip to raise￡100,000(about $144,000) for the Bristol .Children's Hospital. She admired the doctors and nurses and wanted to raise money to allow another family access to treatment.

    Spencer expects to complete her walk next spring. She'd love to finish on Valentine's Day, but doesn't know if that is realistic.

    Tang Dynasty poets sang for about three centuries in different tones. There were many famous poets living in the Tang period such as Li Bai, Du Fu, Bai Juyi and Li Shangyin. Poems of the Tang Dynasty edited in the Qing Dynasty is a collection of more than 48,900 poem that were written by over 2,200 poets. But it didn't cover all the poems of the Tang Dynasty.

    During the Tang Dynasty, poems were recited when lovers walked under the moonlight. Poems were also recited when soldiers fought on the battlefield. People recited them in the open air or at temple fairs.

    Tang Dynasty poets wrote poems to win fame and also to develop their temperament(性情). They poured out deep feelings for their friends and criticized in injustice in the world through poems.

    In the Tang Dynasty scholars had to be poets. Their readers were not only people of high social position but also common people. Poets recited poems, women singers sang poems and other ranks of people, including old women and children, read Tang poems. This atmosphere affected foreigners who visited the country at that time. As a result, Tang poetry was introduced to some adjacent countries, like Japan and Vietnam.

    Tang poetry is a most brilliant page in the history of ancient Chinese literature. It's a miracle in the cultural history of mankind. The Tang Dynasty was a powerful empire with a vast territory. It inherited(继承)Chinese civilization that went back to ancient times, was combined with the best of other cultures and adopted the benefits of other nations in the world. Tang poetry wasn't the only spiritual wealth created by the Tang Dynasty people. Philosophy and religion, handwriting and painting and music and dance all gained new peaks of development. Tang poetry, however, was the jewel in the crown and its greatest achievement.

    Palema Malhotra and her husband Anil Malhotra have spent the last 25 years buying the waste agricultural land and reforesting it, to return the land to a bio – diverse rainforest for elephants, birds and other creatures.

    The couple owns 300 acres of land in Brahmagiri, India. They have spotted more than 300 kinds of birds as well as many rare and threatened animal species. But, this was not the scene in 1991 when Anil and Pamela came to this part of the country. “When I came here, it was a wasteland. The owner wanted to sell because he couldn't grow coffee or anything else,” says Anil who worked in the real estate（房地产）and restaurant business in the US before moving to India. “For me and Pamela, this was what we were looking for all our life.”

    The couple had a love for nature from their childhood. When the Malhotras came to India, the pollution horrified them. “That was when we decided to do something to reclaim（开垦）the forest in India,” says Anil. “We were not looking for money. Early on, we realized that shortage of fresh water will be a concern for India and the rest of the world. Acquisition, protection and reclamation of forested lands and wildlife habitat, where vital water sources have their origin, is the only way to save ourselves,” explains Anil.

    They sold what they owned in America, bought the first 55 acres and began to grow a forest. Soon they bought the land nearby as well. “Many of the farmers considered their holdings 'wasteland' as very little grew on it and were happy to get money,” says Anil.

    Hunting and poaching（偷猎）was a challenge and often the locals did not understand what this couple was doing, so it required a lot of talking to create awareness. They worked with the forest department to set up camera traps and keep poachers away. “There are times I have fought with poachers,” says Pamela.

This summer has brought ex treme heat and droughts to places around the world. The droughts are leading to serious problems and the effects of the droughts are likely to be felt for years. Droughts aren't new, but Earth's rising temperatures because of global warming are making them much harder to avoid. The drought in the Horn of Africa may be the most serious situation. For several years, the area has had very little rain during the rainy seasons. The dry conditions have killed millions of farm animals and destroyed the crops of farmers.

The drought is causing energy problems in Europe, too. The low water levels have cut the amount of hydroelectric power that can be produced. Some rivers are so low that the heavy boats that carry coal can't travel on them.

Farmers in California and Arizona have been hit particularly hard. California has put limits on water use across the state. Now water is being limited in other places. When there are water limits, farmers aren't able to grow as many crops. That can drive up food prices, and that affects everyone.

China is facing similar problems. The drought has dried up much of the water in the Yangtze River. That has cut the amount of energy produced by the world's largest da m by 40%. China hasn't been able to produce enough energy, since millions of people are using electricity to keep cool. The government is calling on the public to turn off the air conditioner when it is not too hot. The country is trying to make it rain by shooting chemicals into clouds. But this is an uncertain and temporary response.

There are no easy solutions to any of these droughts. It took years to create the climate crisis, and it will take a long time to get it under control. For now, governments and people will need to care fully manage water supplies and other resources to limit the damage as much as possible.