News Article | April 23, 2017
China, the world’s rising superpower, is experiencing an explosion of faith. The decades of anti-religious campaigns that followed the 1949 communist takeover are giving way to a spiritual transformation—and among the fastest-growing drivers of that transformation are unregistered churches. Once called “house” or “underground” churches because they were small clandestine affairs, these groups have become surprisingly well-organized, meeting very openly and often counting hundreds of congregants. They’ve helped the number of Protestants soar from about 1 million when the communists took power to at least 60 million today. Of these believers, about two-thirds are not affiliated with government churches. In other words, Protestants in non-government churches outnumber worshippers in government churches two to one. This fascinated me, and I wondered how it happened. Why were these independent churches so effective in appealing to China’s burgeoning middle class? And how do they survive despite government efforts to rein in religious groups not part of government-run places of worship? To find out, I knew it would be important to report from the ground up. If you rely solely on newspaper headlines and human rights reports, you’ll only understand one aspect of a society: its problems. For instance, after reading the recent Freedom House report about intensifying religious persecution under Chinese President Xi Jinping, you may come away with the impression that in China the main story of religion is repression. But any casual visitor to the country can tell you that the number of churches, mosques, and temples has soared in recent years, and that many of them are full. While problems abound, the space for religious expression has grown rapidly, and Chinese believers eagerly grab it as they search for new ideas and values to underpin a society that long ago discarded traditional morality. That’s why I made the southwestern city of Chengdu my second home. Living there for weeks at a time, I followed the progress of Early Rain Reformed Church over the course of a year. This unregistered church has had numerous setbacks and always seems on the verge of being closed down. But it keeps bouncing back, thanks in part to one of the most inspiring preachers I’ve met in any country. When Wang Yi addressed his congregation, he looked like an explorer surveying new horizons. He would grasp his pulpit with both hands, leaning forward on the balls of his feet, his eyes squinting through thick glasses as if focusing on a speck in the distance. He had rosy cheeks and a winning smile, and when he spoke, it was in a strong and forceful voice, his words as clear as his arguments. He had been one of China’s most prominent civil rights lawyers before the government detained or drove most of those people out of their profession. By the time that happened early in the second decade of the 21st century, Wang Yi had already found a new calling. He had converted to Christianity in 2005 and founded Early Rain Reformed Church, quickly establishing himself as one of China’s best-known preachers. His church was independent of government control, but that made it all the more dynamic. Videos of his sermons circulated on social media. His plans, ideas, and ambitions seemed boundless. Protestant Christianity was China’s fastest-growing religion, and Wang Yi was one of its stars. But at times he had been accused of arrogance and talking over people’s heads, of giving theoretical sermons about theological issues that no one could understand. Like most Chinese pastors, he was mostly self-taught in the Bible and tended to bring his lawyer’s argumentative nature to church matters. Tonight, though, was a chance to shine. Behind him on a screen was a picture of a dead woman whom people had come to mourn. Wei Suying, a popular member of the church, known to everyone as Auntie Wei, had died of cancer at age 62. Her daughters testified about how she had persuaded them to convert to Christianity. Both said how it had changed their lives, helping them see through the materialism of contemporary society. They had become better people, less obsessed with money, and more concerned about helping others. A few people began sobbing. Now it was Wang Yi’s turn. A few hours earlier, he had been thinking about how the communists exalt famous people by saying wansui, or long live, like “Long Live Chairman Mao.” Wansui (wan-sway) was a term everyone in China knew. It was almost a prefix before the Communist Party’s name, a formulaic chant meant to guarantee that its rule would never end. Auntie Wei’s death made him realize how much he hated that term. It was an offense to God and to ordinary people like Auntie Wei, whose lives truly deserved exaltation. Talking about this was a bit abstract, but he thought it might work. He stood up to speak, as usual without notes. He started softly, forcing everyone to listen carefully. “Auntie Wei was someone I think it would be fair to call a simple woman. She was a mother and had a hard life. She raised two daughters mostly on her own. Her husband had died young.” One of the daughters began sobbing. People in the church began nodding but caught themselves as Wang Yi continued. “She was not someone who heard the word wansui too often. If she heard it, she would have thought it applied to China, or the Communist Party, or Chairman Mao. Wansui: that’s almost always reserved for them. This is wrong. Wansui, this word, if it belongs to anyone, it belongs to Auntie Wei.” A couple of people looked up startled. “I tell you that she can hear wansui now because she is wansui; she is immortal because of Jesus. It’s not the government that can confer this word. It’s God, and it’s us by how we live our daily lives. It’s the choices we make despite the immoral society we live in. This is what real wansui is. It’s nothing that the Communist Party can provide. It’s something we can make ourselves.” Suddenly people were smiling; this was why they came to Early Rain Reformed Church. It was different from the anodyne churches sponsored by the state. It was warm and direct, but most of all it was relevant. It was for people who didn’t want the status quo, who were searching for alternatives to the life around them. Wang Yi was dressed in a suit, with short cropped hair and an earnest expression—a nice, modern young man, a perfect son-in-law. And yet here he was standing in front of them, telling them directly how to challenge the official way of looking at their country. “Auntie Wei was one of our sisters,” Wang Yi said, winding up his eulogy. “We loved her. But it’s she who possesses eternal life, not the government. She created it for herself by living a good life, by being our sister in the church, and resisting the immorality around her.” Now I could see why Wang Yi had made the choice to become a pastor. When he was a public intellectual, most of his words were censored. But here, speaking to one hundred people in a room, he was contributing to a sense that it was ordinary people who possessed real power in a country where all authority seemed to belong to the state. After the service, a son-in-law of Auntie Wei’s walked up to Wang Yi and did something Chinese almost never do: he hugged him. And Wang Yi, blinking back his own tears, looked bewildered but then happy. This was truly his flock, and he was their pastor. On Ash Wednesday—the beginning of Lent, the solemn 40-day period of fasting and prayer marking the lead-up up to Jesus’s crucifixion and resurrection during Easter—I visited Wang Yi’s church again. Like many religious groups in China, Early Rain operated in a grey area. The church wasn’t banned but also wasn’t permitted by the government. It operated openly but couldn’t buy a plot of land to build a proper church. That forced Early Rain (like hundreds of other unregistered churches across China) to find space in buildings like the River Trust Mansion, a seedy office tower in which it occupied half of the 19th floor. “The police officer comes every week. We don’t want to be stuck in the old underground-church mentality. It’s not healthy.” I saw that Wang Yi was in his office. He looked up and waved me in. As always, he was disarmingly frank. I asked him about his plans to set up a seminary. The idea made me nervous. Had the government approved it? “Well, no, they won’t approve it, but the question is if they’ll shut it down. We don’t think so. They asked us if it’s internal, and we said yes, so they seemed okay with that.” “So the idea is that it’s only to train Early Rain church members,” I said. “But will they go out to preach?” “Definitely; the idea is people from here will become missionaries. They’ll learn here.” “But isn’t this a sensitive year? You know…” I trailed off, wondering if his office was bugged. “You mean the big leadership issue?” Wang asked. “Every year is something special. Last year was some anniversary, and a few years ago were the Olympics. Next year will be something else. Right now the Communist Party is not so stable. We can’t know what is going on inside. They may feel they need quiet at all costs, and we’ll have trouble. Or they could also say that they need quiet so will ignore us; after all, we’re not challenging them. We just trust in God and let Him decide.” As we were talking, a policeman walked in. I thought at first it was just one of the many workers or deliverymen in China who sometimes wear blue uniforms. Then I noticed the insignia. Wang Yi stood up, greeting the officer warmly by name, and quickly led him out. Ten minutes later, Wang Yi returned. “The local police officer. He comes every week to get the list of those who attended church. We give them this information; we have nothing to hide, and the congregants are okay with that too. In fact, it’s a precondition for joining our church. You have to give your name, address, and contact information and be willing for us to share it with the authorities. We don’t want to be stuck in the old underground-church mentality. It’s not healthy.” He pointed to a whiteboard on the wall, which was covered with notes and numbers. “There’s the figure for the Sunday morning service: 222. And the afternoon: 92. So the total was 314. We can only seat around 220, so that’s why we have the second service.” “It’s hardly celebrated here at all,” he said. “We had this break in our history—you know, the missionaries being expelled in 1949 and then the anti-religious campaigns—so a lot has been lost. A lot of people don’t really know too much about Lent. We had a service trying to reintroduce the idea and explain it.” Like Early Rain, many Chinese churches are looking abroad for inspiration. They want all the traditions and import them as a package, assembling them like a model airplane. Wang Yi’s church reminded me of The Missionary’s Curse, a book by the British scholar Henrietta Harrison. She traces the history of Cave Gully, a village in northern China that converted to Catholicism in the late 17th century, when local businesspeople heard of the faith in Beijing and brought it back home. They acquired prayer books and some fragmentary knowledge but no systematic understanding of the faith. The result was something highly indigenized. God was seen as another version of the Chinese concept of heaven, or tian. Worship of Mary was conflated with worship of popular female deities in northern China, such as the Buddhist goddess of mercy, Guanyin. The Ten Commandments were a kind of moral formula, familiar to local people through Confucian texts. Western missionaries who tried to correct these practices were rebuffed. But by the 19th century, China was opening up. Rail, telegraph, steamships, and other technological innovations created the first era of globalization. Catholics in Cave Gully realized that they were part of something bigger—a global Catholic Church with rules and standard theological interpretations. Soon, people looked to Rome for benchmarks of how to be a good Catholic. In other words, the opposite of indigenization took place. The religion started with the familiar—respect for a supreme deity, a popular female goddess, moral rules—but moved beyond these easily digested universal manifestations of religion to uniquely Catholic ideas, such as the supremacy of the pope. This history is reflected in Wang Yi and the congregation of Early Rain. They also long to be part of a global movement—something orthodox, standard, and authentic, and not “indigenous.” Harrison sees this as applying not only to Christians but to Chinese society as a whole: As contact increases, international norms and standards seep in. Just as people want to be “real” Christians, they also yearn for a country that is truly committed to human rights, rule of law, and justice. They long for authenticity. Early Rain’s annual meeting was held on a Saturday, on the last full moon before the Spring Festival. Over the past year, the congregation had supported the families of political prisoners and Chengdu’s homeless while trying to balance the needs of its own poor members. It had founded a seminary that was helping its own members deepen their understanding of Christianity and also training dozens of pastors from across China. It had held an inspiring Christmas service despite government harassment. And the church had formed an alliance with two other Reformed churches in Chengdu. Quietly, Wang Yi had traveled farther afield, too, making preliminary contacts across China in hopes of forming a loose coalition of like-minded, urban-based churches. I had been wondering how long he could continue preaching before he would get in trouble. It wasn’t really his sermons that made me wonder. Instead, it was that his church was a parallel realm outside the party’s control. It had its own nursery school, day care, seminary, and elementary school—all located on this floor in the River Trust Mansion that it owned. It handled its own finances, rejecting all foreign money. It held its own elections and annual meetings—just like the government’s, but more transparent. The meeting was efficient and informative, with half a dozen people giving presentations on different aspects of the church. We heard from subcommittees that handled youth work, education, legal affairs, and finances. All of them had PowerPoint presentations and spoke quickly, confidently, and firmly—not unlike the lists, plans, and goals presented by the government during its springtime meetings of parliament. But what they also wanted was passion, and this could only be offered by Wang Yi. They had heard the nuts and bolts, but they needed a vision. “If we’re thrown out of Chengdu, we’re going to get back on the bus and reenter the city.” Wang Yi’s speech ended the meeting. The key for the coming year, he said, was growth. This would only be possible by splitting the church and moving some of the congregants to a new home. Right now, Early Rain had to turn away about 70 for lack of space. Those people would found a new church in the city’s center, near Sichuan University. This was a classic church-planting technique that was outlined in books that the seminary had studied last summer. The books had been published in the United States and translated into Chinese and were now being used as a template. Wang Yi and his deputies had discussed this for many months and decided it was a way also to protect Early Rain. If the mother church were to be closed, then the southern branch could keep going. The church, Wang Yi said, had to grow because Chengdu was growing too. Rural China was emptying out. So growth had to take place here, in big cities that were becoming regional and even international hubs. As always, his lecture had a pedagogical flare: He loved to explain, and the audience loved to learn. Wang Yi described how cities have always played a big role in Christian history—the city on the hill referred to by Jesus and founders of new Christian communities through the ages. “Ever since I was little, I thought that the city was my dream. But why do we want to live in cities?” In the Bible, Wang Yi continued, cities are sometimes shown to be bad; Babylon, for example, was the epitome of worldly sin. But cities are also places for people to better themselves and develop their potential. “I’ll use one word: ‘opportunities.’ What sorts of opportunities? Hope is one. When I was growing up, we used to say, ‘Hong Kong, Hong Kong, why are you so fragrant?’ “It represented capitalism, reform, and opening. It was the goal of every Chinese city to be like Hong Kong. Especially people like me who are from small towns and come to a big city, they want to stay. They also come for culture, for justice, and for generosity. People don’t go to a village to get an education. They go to the city—to the schools or the bookstores. Petitioners don’t go to a village to appeal for help; they go to the city. Beggars come to the city. They don’t go to the countryside. “Entering the city is what Jesus did in Jerusalem. Entering the city is entering a place of justice, of generosity, and of spreading the Gospel. It’s a place of hope. And it’s why we’re in the city here, and growing here. “In the Acts of the Apostles, when Paul was in Lystra spreading the Gospel, what happened? Some people wanted to worship him, thinking he was Zeus. But some stoned him almost to death, and when they thought he wasn’t breathing, they threw him out of the city. But he got up and went back into the city. This line really shocked me. It’s from chapter 14, verse 20: ‘He got up and went back into the city.’ He was thrown out of the city, but he reentered it. “So if we’re thrown out of Chengdu, we’re going to get back on the bus and reenter the city. And the goal isn’t because of opportunities, or culture, but it’s because it is the city that has the chance for peace, for generosity, and for the Gospel. God wants us to be in this city.” I looked around the room. About half the congregation had closed their eyes but had light smiles on their faces, listening to a vision. It was a prophecy of struggle—of perhaps being closed by the government, but also of determination, hope, and victory. Wang Yi stood before them, looking out on his congregation, confident and firm. Then he made his pitch, his claim for them to think of their hometown as more than just another city, but that it and their lives were the center of a great movement. “Earlier today, some disciples asked me what was the main theme of today? I said it’s ‘Entering the city.’ And they said, ‘Well, aren’t we already in Chengdu? Why do we need to enter the city?’ The answer is we need to keep entering the city. The city is the history of humanity’s hope for the future. There’s the city of God and the city of man. In the past it was Babylon, or New York, or Hong Kong, or Chengdu. “When we talk to brothers and sisters, we should ask them, why are you in Chengdu? What sorts of dreams have brought you here? And what are our dreams? We are creating a Jerusalem. This is the city on the hill. For us, Chengdu is this city.” This article has been adapted from Ian Johnson’s book, The Souls of China: The Return of Religion After Mao. Read more from The Atlantic: This article was originally published on The Atlantic.
News Article | April 18, 2017
Last April, for example, Sichuan University scientists announced that they had used CRISPR to program T cells from the immune system of a person with lung cancer to kill tumor cells (Nature 2016, DOI: 10.1038/nature.2016.20988). And late last year, a UC Berkeley team reported harnessing the technology to correct the genetic mutation responsible for sickle cell anemia in stem cells from patients with the disease (Sci. Transl. Med. 2016, DOI: 10.1126/scitranslmed.aaf9336). Eventually, Doudna; Emmanuelle Charpentier, now the director of the Max Planck Institute for Infection Biology; and coworkers discovered that CRISPRs help bacteria fight viral infection. Bacteria snag bits of an invading virus’s RNA and tuck them into CRISPRs, the team found. If the virus strikes again, these modified CRISPRs bind to the pathogen’s DNA, signaling to the enzyme Cas9 to come and dice up the foreign genetic material. The researchers realized they could harness this machinery to cut and paste target DNA fragments at will, as long as they introduced the appropriate designer RNA sequences. What started as a small project “aimed at something seemingly unrelated … led to a very different direction,” Doudna said during the Kavli keynote address on April 3 at the ACS national meeting in San Francisco. C&EN caught up with Doudna at the meeting to discuss the importance of curiosity-driven basic research and her outlook for CRISPR. The convergence of chemistry with other disciplines to tackle interesting problems in science is exciting. More and more, I see chemists using gene editing to make precise changes to molecules, such as proteins. That allows them to connect discoveries made using purified biomolecules outside cells—enzymes reacting in lab vessels, for instance—to what you would find in a living organism. That’s really amazing. With better chemical understanding of the way these enzymes operate, it will be possible to use them in ways that they don’t seem to be deploying in nature. The ability to make changes to the DNA of plant cells also opens up opportunities both in research and in solving problems in agriculture. That includes helping plants defend themselves against infection, drought, and other climate-change-related issues from a chemical perspective. With CRISPR, you understand the precise changes that you’re making to DNA—at the level of individual base pairs—rather than randomly introducing changes by exposing plant seeds to chemicals that cause DNA mutations. In drug discovery, one of the big challenges for chemists is determining the targets of small molecules. Now, you can potentially very rapidly figure out the targets by using CRISPR to query cells on a genomewide scale. You can disrupt certain genes and then ask if cells are still susceptible to the small molecules. I’m excited about that as an important research application but also as a practical way of doing drug discovery. We can do gene editing on cells ex vivo—meaning outside the organism—and the edited cells can then be reintroduced to the body, which gets around the challenge of drug delivery. For clinical use, we’ll probably see treatments like this that involve immune cells in the blood first, since they can be collected outside the body. In agriculture, we’ve already begun seeing products that have been created using precision gene editing. That brings up a bunch of regulatory challenges. The U.S. Department of Agriculture has decided that plant products created using CRISPR that don’t introduce foreign DNA are not considered genetically modified, which has led to lots of discussion. In other countries, the regulation of GMO plants is different, so I think people are being pushed to reevaluate how these are defined based on the opportunities we now have with CRISPR. Where we’ll likely see advancements being made is in deploying CRISPR to do more specific kinds of things. One is using it not to cleave DNA directly but to make a direct chemical modification to DNA, whether it’s changing one nucleotide base into another one or adding a methyl group. CRISPR has made possible genetic changes in individual organisms and even made it possible to pass along changes to offspring. This raises ethical concerns, particularly regarding human embryo or germ-line editing that might lead to permanent changes in the DNA that can be passed on to future generations. I’ve been actively involved in discussing these issues. As scientists, we need to explain what we’re doing and why we’re doing it, not dictating how these discoveries and technologies should be used. We need to participate in those conversations with the public. This is important, especially now, when there’s a lot of questioning about scientific knowledge, the value of facts, and how scientific data are used to help governments make decisions about regulations and funding. In February, the U.S. Patent & Trademark Office upheld patents awarded to the Broad Institute of Massachusetts Institute of Technology and Harvard University for the use of CRISPR in eukaryotic cells. About a month later, the European Patent Office announced plans to award a patent to the University of California that covers a wide range of CRISPR uses. How do you see the patent battle playing out in the years ahead? Patents around important technologies typically are complicated. It takes a while to sort them out, and CRISPR is no different. Honestly, I think it will take a while before the patent situation is resolved in different countries. The exciting thing for me is that we’re seeing rapid deployment of the CRISPR technology both in academic settings and in companies. That’s leading to real advances for various diseases. There are exciting uses in agriculture and in fundamental research. None of that is being hampered by the current patent situation. CORRECTION: This Q&A was updated on April 21, 2017, to correct the affiliation of the team that used CRISPR to fix the genetic mutation responsible for sickle cell anemia in patients’ stem cells. It is UC Berkeley, not Stanford.
News Article | April 27, 2017
Since its inception, MMAAP foundation has awarded over 40 Fellowship and Project grants to support the work of exceptional physician scientists and investigators with the vision, drive and dedication to find new and innovative ways towards advancements in the targeted medical fields. These outstanding award recipients represent more than 20 prestigious Chinese medical institutions including Peking Union Medical College Hospital, Xijing Hospital, the Fourth Military Medical University, Peking University Institute of Hematology, West China Hospital, Sichuan University, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, and others. "The visionary leadership of MMAAP Foundation Chairman and Founder, Howard P. Milstein, has brought together and funded exchanges between outstanding researchers, medical talent, and institutions in these regions," said Sean X. Leng, MD, PhD, President of MMAAP Foundation. "The 2017 recipients are among the most talented investigators in their fields and our support of their work is vital to both furthering medical research and strengthening relations between the U.S. and China." Grant applications were evaluated through a two-step peer review process according to the National Institute of Health standard. Panels of Chinese and U.S. experts in their respective fields jointly reviewed all proposals, and finalists were submitted for approval by MMAAP Foundation. The U.S. panels in Geriatrics, Skin Disease, Hematology, Reproductive Medicine, and Translational Medicine include members of the American Geriatrics Society, Medical Advisory Committee of American Skin Association, New York Blood Center, Jones Foundation for Reproductive Medicine, as well as members of other leading U.S. institutions in each field. The mission of Milstein Medical Asian American Partnership Foundation (MMAAP Foundation) is to improve world health by developing mutually beneficial partnerships between the U.S. and China, as well as greater Asia. Working with some of the premier health organizations in the world, MMAAP Foundation brings together and funds exchanges among the best research, medical talent, and institutions in the regions. This strategy is a high priority for MMAAP Foundation's founder Howard P. Milstein. MMAAP Foundation is a 501(c) (3) non-profit organization. For more than 50 years, the Milstein family has been actively involved in health-related and medical philanthropy. MMAAP Foundation builds upon this distinguished history in five areas: Senior Healthcare, Skin Disease and Melanoma, Reproductive Biology, Blood Research, and Translational Medicine. MMAAP Foundation works in close collaboration with other medical organizations supported by the Milstein family, including American Skin Association, Milstein Melanoma Research Program at The Rockefeller University, Howard and Georgeanna Jones Foundation for Reproductive Medicine, New York Blood Center, and the Program for Translational Chemical Biology at New York-Presbyterian Hospital/Weill Cornell Medical Center. For more information, please visit MMAAP Foundation's website at www.mmaapf.org. To view the original version on PR Newswire, visit:http://www.prnewswire.com/news-releases/milstein-medical-asian-american-partnership-foundation-announces-2017-fellowship-and-project-awards-300447740.html
Fu Z.,Sichuan University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012
The s-wave pion-kaon (πK) scattering lengths at zero momentum are calculated in lattice QCD with sufficiently light u/d quarks and strange quark at its physical value by the finite size formula. The light quark masses correspond to m π=0.330-0.466GeV. In the Asqtad improved staggered fermion formulation, we measure the πK four-point correlators for both the isospin I=1/2 and 3/2 channels, and analyze the lattice simulation data at the next-to-leading order in the continuum three-flavor chiral perturbation theory, which enables a simultaneous extrapolation of πK scattering lengths at the physical point. We adopt a technique with the moving wall sources without gauge fixing to obtain substantiable accuracy; moreover, for the I=1/2 channel, we employ the variational method to isolate the contamination from the excited states. Extrapolating to the physical point yields the scattering lengths as m πa 3/2=-0.0512(18) and m πa 1/2=0.1819(35) for the I=3/2 and 1/2 channels, respectively. Our simulation results for πK scattering lengths are in agreement with the experimental reports and theoretical predictions, and can be comparable with other lattice simulations. These simulations are carried out with MILC N f=2+1 flavor gauge configurations at lattice spacing 0.15fm. © 2012 American Physical Society.
Fu Z.,Sichuan University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012
A proposal by Lüscher enables us to extract the elastic scattering phases from two-particle energy spectrum in a cubic box using lattice simulations. Rummukainen and Gottlieb further extend it to the moving frame, which is devoted to the system of two identical particles. In this work, we generalize Rummukainen-Gottlieb's formula to the generic two-particle states where two particles are explicitly distinguishable, namely, the masses of the two particles are different. Their relations with the elastic scattering phases of two-particle energy spectrum in the continuum are obtained for both C 4v and C 2v symmetries. Our analytical results will be very helpful for the study of some resonances, such as kappa, vector kaon, and so on. © 2012 American Physical Society.
Wu J.,Sichuan University |
Xiao D.,Sichuan University |
Zhu J.,Sichuan University
Chemical Reviews | Year: 2015
High-performance lead-free piezoceramics have become an international research frontier in the fields of high technology and new materials. (K,Na)NbO3 (KNN) has become one of the most extensively investigated piezoelectric systems. Researchers have reviewed the advances o f KNN-based materials from d ifferent viewpoints, greatly accelerating research progress. Rodel and co-researchers reviewed the phase structure and electrical properties of KNN-based materials by analyzing different processing techniques and chemical modifications. Panda reviewed the effects of additives on the electrical properties of KNN-based materials. In 2009, Xiao et al. reviewed the composition design and property modification of KNN- and BNT-based ceramics by considering their recent publications. Enhanced piezoelectric activity was observed in PZT materials with a Zr/Ti ratio of 52:48 owing to the structural changes going from tetragonal to rhombohedral via an intermediary monoclinic phase. Researchers have confirmed that potassium-sodium niobate lead-free piezoceramics will be a promising lead-free materials for actuator applications.
Wang J.,Sichuan University |
Liu X.,Sichuan University |
Feng X.,Sichuan University
Chemical Reviews | Year: 2011
The Strecker reaction was first documented by the German chemist Adolph Strecker (1822-1871) in 1850. Strecker reactions using chiral aldehyde- or ketone derived imines can be found in many natural product syntheses of specific structures, this strategy tends to be extremely specific and highly structure-dependent. Cainelli and co-researchers reported the asymmetric Strecker reaction of N-substituted aldimines derived from the O-protected (2S)-lactic aldehydes. Cativiela and co-workers studied the diastereoselective Strecker reaction of chiral aldimines derived from protected D-glyceraldehydes. The best results were obtained when the reactions were carried out at room temperature in CH2Cl2 in the absence of a Lewis acid. In 1994, Reetz et al. reported the highly diastereoselective Strecker reaction of three classes of N-protected aldimines derived from chiral N,N-dibenzylamino aldehydes, which could be prepared from the corresponding enantiopure α-amino acids.
Yao J.,University of Sichuan |
Yang M.,University of Sichuan |
Duan Y.,University of Sichuan |
Duan Y.,Sichuan University
Chemical Reviews | Year: 2014
The combination of fluorescence and nanomaterials has developed into an emerging research area: fluorescent nanoparticles. Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology and have attracted increasing interest for bioanalytical labeling applications in recent years. The emerging development and innovation of luminescent nanoparticles (NP) with unique optical properties, yet complicated surface chemistry, paves new roads for fluorescence imaging and sensing as well as for in vitro and in vivo labeling in cells, tissues, and organisms. The labeling procedure can be straightforward provided that suitable functional groups are available on the target analyte. However, it can be difficult to reach a low detection limit in fluorescence detection due to the limited extinction coefficients or quantum yields of traditional organic dyes and also low dye-to-reporter molecule labeling ratio.
Yang C.,Sichuan University |
Inoue Y.,Osaka University
Chemical Society Reviews | Year: 2014
Supramolecular photochirogenesis is a rapidly growing interdisciplinary area of science at the boundary of photochemistry, asymmetric synthesis and supramolecular chemistry. The major advantage of supramolecular photochirogenesis over the conventional molecular one is entropic in origin, being achieved by preorganizing substrate(s) in the ground state and manipulating subsequent photochemical transformation by weak but non-transient interactions in chiral supramolecular media. The chirality transfer often becomes more efficient through the cooperative non-covalent interactions and the confinement by host in both ground and excited states. Thus, all of the ground- and excited-state events, including complexation stoichiometry and affinity, chiroptical properties, photophysical behaviour and photochemical reactivity, jointly play pivotal roles in supramolecular photochirogenesis. This may appear to cause complication but in reality expands the range of manipulable factors and available experimental/theoretical tools for elucidating the mechanism and controlling photochirogenic processes both thermodynamically and kinetically, from which some new concepts/methodologies unique to supramolecular photochemistry, such as non-sensitizing catalytic photochirogenesis and wavelength-controlled photochirogenesis, have already been developed. In this review, we will discuss the recent progress and future perspective of supramolecular photochirogenesis. This journal is © the Partner Organisations 2014.
Liu X.,Sichuan University |
Lin L.,Sichuan University |
Feng X.,Sichuan University
Accounts of Chemical Research | Year: 2011
Homochiral catalysts that can effect asymmetric transformations are invaluable in the production of optically active molecules. Researchers are actively pursuing the design of new ligands and organocatalysts by exploiting concepts derived from the application of bifunctional and C2- symmetric catalysts. Many homochiral catalysts containing amines, ethers, alcohols, and phosphines as electron-pair donors have been successfully developed.Amine N-oxides are highly polar substances. Despite their pronounced capacity as electron-pair donors, N-oxides have been underutilized in asymmetric reactions; they have only made a visible impact on the field in the preceding decade. Systematic studies have instead largely focused on pyridine- or quinoline-based scaffolds in organosilicon and coordination chemistry. The application of chiral tertiary amine N-oxides has not been widely pursued because of the difficulty of controlling the chirality at the tetrahedral nitrogen of the N-oxide moiety. In this Account, we outline the design of a new family of C2-symmetric N,N′-dioxides from readily available chiral amino acids. We then discuss the application of these chiral amine N-oxides as useful metal ligands and organocatalysts for asymmetric reactions.The high nucleophilicity of the oxygen in N-oxides is ideal for organocatalytic reactions that rely on nucleophilic activation of organosilicon reagents. These catalysts have been successfully applied in the asymmetric addition of trimethylsilylcyanide to aldehydes, ketones, aldimines, and ketimines, with good yields and excellent enantioselectivities. Asymmetric organocatalytic chlorination of β-ketoesters with N-chlorosuccinimide has also been achieved through hydrogen bond activation.The molecular framework of these N,N′-dioxides, with their multiple O-donors, also serves as a new tetradentate ligand that can coordinate a range of metal ions, including Cu(I), Cu(II), Ni(II), Mg(II), Fe(II), Co(II), In(III), Sc(III), La(III), Y(III), Nd(III), and others. These versatile metal complexes are efficient catalysts for a variety of asymmetric reactions. Asymmetric cycloadditions have been achieved with these chiral Lewis acid catalysts. We have also found success with asymmetric nucleophilic additions to C=O or C=N bonds; substrates include 3-substituted 2-oxindoles, alkenes, enamides, enecarbamates, diazoacetate esters, nitroalkanes, glycine Schiff bases, and phosphate. Notably, the first catalytic asymmetric Roskamp reaction was realized, which was successful because of the high efficiency of the catalyst. Asymmetric conjugate additions between α,β-unsaturated compounds and nucleophiles such as nitroalkane, malonate, thioglycolate, and indoles have been accomplished. The first asymmetric haloamination of chalcones was discovered, and the reaction proceeded with high regio- and enantioselectivity. In some cases, we were able to reduce the catalyst loading to just 0.01-0.05 mol % while maintaining excellent outcomes.Some particularly interesting phenomena were observed over the course of the research. These include a remarkable amplification of the asymmetry in a sulfa-Michael reaction, as well as the reversal of enantioselectivity after alteration of the central metal or the subunits of the ligand in two other reactions. These unusual results have facilitated a deeper understanding of the catalytic mechanism. © 2011 American Chemical Society.