Funny&Amazing Pics&Facts: сентября 2016

пятница, 30 сентября 2016 г.

WE ARE CLOSER TO CURING ALL DISEASES THAN WE THINK

Breast Cancer Cell

Color-enhanced shot of a breast cancer cell

FOR CANCER CARE, ACCESS TO TREATMENT MAY BE THE BIGGEST OBSTACLE

Last week, Facebook CEO Mark Zuckerberg and his wife Priscilla Chanannounced an ambitious project—to “invest in basic science research with the goal of curing disease.” The couple started by donating $3 billion over 10 years in this initiative, which target four major groups of illnesses: cancer,infectious diseases, as well as heart and neurological diseases.

The desire to ‘cure all disease’ is laudable, and $3 billion is a nice, albeit small amount of money in the grand scheme of medical research funding. However, a really important question we should all be asking is can we really find cures for all diseases? Well, according to scientists, it depends on which ones you’re talking about. But in general, while we might not be there yet, we may be closer in our understanding of the causes of disease than we think.

In the case of infectious disease, the objective to "cure, prevent, and manage” is trickier than it looks. Eric Rubin, an immunology and infectious diseases researcher at Harvard's T.H. Chan School of Public Health, says that pathogens—which are any infectious disease-causing bugs like bacteria, viruses, or other microorganisms—evolve at different rates. The ones that evolve at a slow rate, like the bacterium that causes leprosy or the one that causes Guinea worm disease can be cured. But addressing rapidly evolving pathogens like the flu is far more challenging.

“The influenza virus that infects us every year is different from the influenza virus from last year,” says Rubin, who is “optimistic” about the $3 billion project. “In fact, it’s different from multiple different [flu] viruses circulating at any given time.” Some of those changes are small Rubin says, and in those cases, the immunity we have still protects us. But if the changes are large, then our pre-existing immunity isn’t very good.

That’s not to say rapidly evolving pathogens cannot be moderated, says Rubin. He says that as a pathogen evolves to resist something, it becomes less fit to grow and cause illness.

According to Francis S. Collins, the Director of the National Institutes of Health, while it’s hard to imagine a world where there are no infectious diseases, we can certainly create one where they can be controlled.

“We will not banish infectious disease from Earth but we will have strategies to quickly combat them if they do emerge,” says Collins. “I do think what we can do is to develop an increasingly nimble system to identify the emergence of new infectious disease problems and quickly put in place the kind of prevention and treatment strategies that will be needed. We are already accelerating that pace.”

When it comes to cancer, things are a bit different. With over 100 different types of cancer—each of which impacts individuals differently based on an array of factors including age, sex, racial/ethnic group, and geographic location—the progress being made is significant.

“Even though it’s 200 plus diseases, with the trajectory we are on now, in the next couple of decades, we are going to have a tremendous amount of progress being made in managing [cancer] and for an increasing large number of patients, curing [it],” says Ronald DePinho, president of The University of Texas MD Anderson Cancer Center.

DePinho says he is optimistic in progress being made in preventing, detecting, and treating cancer, but the largest obstacle is the disparity in access in areas of the world where there is a “disparity gap” in access and quality care.

“Cancer will always be with us because advancing age is the most important instigator for the development of cancer. It’ll be with us,” says DePinho. “The biggest issue we’re going to face in cancer is not so much the blueprint to prevent, detect or manage disease, but the access.”

Ultimately the notion of curing disease varies from condition to condition, but Collins says it is a feasible one.

“It’s a bold audacious goal, but I like audacious goals, and I think developing cures for all diseases is certainly something that we could imagine happening in the course of this century,” says Collins. “Whether we would successfully apply those to every person who is afflicted is another question but research ought to be able to tackle everything we see in front of us with all the vigor that we got.”

Jessica Cantlon seeks the origins of numerical thinking

Cognitive neuroscientist Jessica Cantlon wants to find out how humans understand numbers and where that understanding comes from.

Brain scans and behavioral tests add up to explain an intriguing evolutionary question

Jessica Cantlon, 40
Cognitive neuroscientist
University of Rochester

The first time Jessica Cantlon met Kumang at the Seneca Park Zoo, the matriarch orangutan regurgitated her previous meal right into Cantlon’s face. “I was retching,” Cantlon recalls. “It was so gross.” But Cantlon was there to kick off a series of behavioral experiments, and her students, who would be working with Kumang regularly, were watching. “Does anyone have any towels?” she remembers asking, knowing she had to keep her cool.

Cantlon’s deliberate nature and whatever-it-takes attitude have served her well. As a cognitive neuroscientist at the University of Rochester in New York, she investigates numerical thinking with some of the most unpredictable and often difficult study subjects: nonhuman primates, including orangutans, baboons and rhesus macaques, and — most remarkably — children as young as age 3. Both groups participate in cognitive tests that require them, for example, to track relative quantities as researchers sequentially add items to cups and to distinguish between quantities of assorted dots on touch screens. The kids also go into the functional MRI scanner where, in a feat impressive to parents everywhere, they lie completely still for 20 to 30 minutes so Cantlon and colleagues can get pictures of their brains.

“She takes steps carefully, and she thinks very hard about where she is going,” says Daniel Ansari, a developmental cognitive neuroscientist at the University of Western Ontario in London, Canada, who is familiar with Cantlon’s work. “She goes for the big questions and big methodological challenges.”

The central question in Cantlon’s research is: How do humans understand numbers and where does that understanding come from? Sub-questions include: What are the most primitive mathematical concepts? What concepts do humans and other primates share? Are these shared concepts the foundation for fancier forms of mathematical reasoning? In addressing these questions, Cantlon draws on a wide range of methods. “Very few people can combine work on cognitive skills — studies from the point of view of behavior — with imaging work in very young children, and very few people do that same combination in nonhuman primates,” says Elissa Newport, who chaired the brain and cognitive sciences department at Rochester for more than a decade and now leads the Center for Brain Plasticity and Recovery at Georgetown University.

As a graduate student, Cantlon determined that neuroimaging studies would add an independent source of data to the cognitive questions under exploration in Elizabeth Brannon’s lab at Duke University. So she identified collaborators and taught herself functional MRI. “By the time she graduated, she had something like four dissertations' worth of work,” says Brannon, now of the University of Pennsylvania.

In the years since, Cantlon has identified a type of “protocounting” in baboons; they can keep tabs on approximate quantities of peanuts as researchers increase those quantities (SN Online: 5/17/15). In her most attention-grabbing work, Cantlon studied activity in the brains of children while they watched Sesame Street clips that dealt with number concepts — an unexpected success that proved everyday, relatively unaltered stimuli can yield meaningful data. An ongoing study in Cantlon’s lab seeks to find out how monkeys, U.S. kids and adults, and the Tsimané people of Bolivia, who have little formal education, distinguish between quantities. Do they determine the number of dots presented on the computer screen or do they rely on a proxy such as the total area covered by the dots?

The work explores how the brain understands everyday concepts, but it could also inform strategies in math education. “If we understand the fundamental nature of the human brain and mind, that might give us a better insight into how to communicate number concepts to kids,” Cantlon says.

Growing up outside of Chicago, Cantlon enjoyed digging deep into a topic and becoming an expert. She and a friend turned themselves into ice skating superfans one summer, reading up on the Olympic skaters and checking videos out of the local library. In another project, Cantlon decided to learn everything possible about the price of gold. When she moved to a school where she could no longer take Latin, she taught and tested herself. Despite the fact that neither of her parents went to college, no one ever questioned that Cantlon would go. She studied anthropology as an undergraduate at Indiana University in Bloomington. “I was interested in the question of where we come from,” Cantlon says. “I was interested in studying people.”

Sabina, an olive baboon, participates in tests that help reveal how primates understand quantities.

During college, she went on an archaeological dig in Belize and studied lemurs in Madagascar. For a year after graduation, she observed mountain gorillas in Rwanda, detailing their behavior every 10 minutes. “What they were thinking was something that was constantly on my mind,” she says. “‘How are we similar? Are you thinking what I’m thinking?’” Though she might have succeeded in any number of careers, she wanted exploration to be a big part of her life: “I don’t think doing a less exotic type of work would have been as satisfying.”

Today, Cantlon, who at age 40 recently earned tenure, doesn’t spend much time in the field. And even in the lab, she leaves much of the data collection to her graduate students and research assistants. “At this point, we are a well-oiled system,” she says, referring to the brain scan studies on kids.

To make the kids comfortable, Cantlon’s team does trial runs in a mock scanner, describing it as a spaceship and providing “walkie-talkies” for any necessary communication. To keep them interested, the researchers treat it as a team activity and offer a ton of positive reinforcement, with prizes including Lego sets and a volcano-making kit. The kids receive pictures of their brains, which typically interest the parents most. The older of Cantlon’s two daughters, a 5-year-old extrovert named Cloe, has participated in behavioral tests and will no doubt be excited for her first brain scan.

The Sesame Street study was in part inspired by a paper by Uri Hasson, a neuroscientist at Princeton University who imaged the brains of volunteers while they watched The Good, the Bad and the Ugly. To better understand brain development, Cantlon wanted to see how brain activity compared in kids and adults exposed to math in a natural way. Of particular interest was a region called the intraparietal sulcus, or IPS, thought to play a role in symbolic number processing. The results, reported in PLOS Biology in 2013, showed that kids with IPS activity more closely resembling adults’ activity performed better on mathematical aptitude tests.

“It was the clearest, cleanest — did not have to come out this way — result,” Cantlon says.

Cantlon is notable for her diverse set of tools, says Steve Piantadosi, a computational neuroscientist and colleague at Rochester. “But she has something which is even more powerful than that. If you have different hypotheses and you want to come up with the perfect experiment that distinguishes them, that is something she is very good at thinking about. She is a great combination of critical and creative.”

To add another methodological approach, Cantlon next plans to collaborate with Piantadosi to develop computational models that explain the operations the brain performs as it counts or compares quantities. She would also like to add data analyses from wild primates into the mix. When researchers talk about the evolution of a primitive number sense, they often speak about foraging activity — identifying areas of the forest with more food, for example. But Cantlon wonders whether social interactions also require some basic understanding of quantities.

As for a recent question from a colleague about what risky project she’ll pursue now that she has tenure, Cantlon says nothing in particular comes to mind: “I feel like we’ve been doing the crazy things all along.”

Citations

J. Cantlon et al. The origins of counting algorithms. Psychological Science. Vol. 26, June 2015. doi: 10.1177/0956797615572907.
J. Cantlon and R. Li. Neural activity during natural viewing ofSesame Street statistically predicts test scores in early childhood. PLOS Biology. Published online January 3, 2013. doiI: 10.1371/journal.pbio.1001462.
U. Hasson et al. Intersubject synchronization of cortical activity during natural vision. Science. Vol. 303, March 12, 2004. doi: 10.1126/science.1089506.
A. Strandburg-Peshkin et al. Shared decision-making drives collective movement in wild baboons. Science. Vol. 348, June 19, 2015. doi: 10.1126/science.aaa5099.

Выявлен биомаркер старения

Резюме. Речь идет о метилировании ДНК, возникающем в результате естественного процесса старения

От чего зависит продолжительность жизни? Почему некоторые люди, ведущие здоровый образ жизни, не доживают даже до пожилого возраста? В ходе нового исследования ученые из 7 стран под руководством доктора Стива Хорватса (Steve Horvath) из Калифорнийского университета в Лос-Анджелесе (University of California, Los Angeles — UCLA), США, оценивали изменения человеческой ДНК, ассоциированные с возрастом. Они получили доказательства того, что продолжительность жизни в большей степени зависит от биологического возраста, чем паспортного. Результаты работы опубликованы в журнале «Aging».

В ходе работы ученые проанализировали более чем 13 тыс. образцов ДНК, полученных от жителей США и Европы, с применением различных молекулярных методов, включающих оценку «эпигенетических часов», по методике, разработанной в 2013 г., которая заключается в подсчете участков метилирования ДНК, возникающих в результате естественного процесса, происходящего с течением времени. Сравнивая паспортный и биологический возраст участников, определенный с помощью «эпигенетических часов», ученые высказывали предположения о продолжительности жизни каждого из них. Оказалось, что результаты, полученные с помощью данного метода, отличаются высокой степенью достоверности, даже после учета других известных факторов риска, таких как возраст, пол, отношение к курению, индекс массы тела и наличие хронических патологий. В то же время ученые выявили, что у 5% населения биологический возраст увеличивается значительно быстрее, чем у их сверстников, что приводит к сокращению продолжительности жизни и повышает вероятность смерти в любом возрасте на 50%.

Авторы исследования полагают, что полученные предварительные выводы могут служить объяснением того, почему некоторые люди умирают в молодом возрасте, даже придерживаясь здорового образа жизни, правильно питаясь, регулярно занимаясь спортом и избегая пагубных привычек. Несомненно, особенности поведения существенно влияют на продолжительность жизни, но естественные процессы старения не прекращаются в любых условиях. Однако следует помнить, что такие факторы, как курение, сахарный диабет и высокое артериальное давление, повышают риск преждевременной смерти более ощутимо, чем скорость эпигенетического старения.

Ученые долго искали биомаркеры биологического старения. Они заметили, что в гериатрии всегда бросается в глаза несоответствие между паспортным возрастом человека и его физическим состоянием. Теперь можно рассматривать процессы метилирования ДНК в качестве биомаркера биологического возраста, и исследователи надеются, что, если в будущем им удастся доказать, что именно эти процессы ускоряют старение, следующим шагом будет разработка стратегии по их замедлению для увеличения продолжительности жизни. Однако точная роль эпигенетических изменений в процессах старения остается неизвестной. Исследователи сегодня еще не могут ответить на вопросы о том, ассоциированы ли данные изменения с возрастом и риском смерти у людей пожилого возраста или же они способствуют развитию каких-либо патологий, а может быть, и вовсе противостоят прогрессированию хронических заболеваний. Для ответа на эти вопросы необходимо проведение дополнительных исследований.

Согласно данным, предоставленным специалистами Всемирной организации здравоохранения, к 2017 г. впервые в истории человечества во всем мире число лиц старше 65 лет будет превышать количество тех, которые еще не достигли 5-летнего возраста. К 2050 г. доля мирового населения ≥60 лет увеличится вдвое (с 11 до 22%). Ученые отмечают, что многие страны окажутся плохо подготовленными к высокому уровню различных хронических заболеваний и инвалидности, характерных для людей пожилого возраста. Следовательно, важной целью, которую ставят перед собой сегодня специалисты, является поиск механизмов, позволяющих поддерживать здоровье у людей старшего возраста. Метод анализа «эпигенетических часов» может быть использован для оценки эффективности предлагаемых подходов, направленных на замедление процессов старения.

University of California, Los Angeles (UCLA), Health Sciences (2016) Epigenetic clock predicts life expectancy. ScienceDaily, Sep. 28 (http://www.sciencedaily.com/releases/2016/09/160928141035.htm).

Юлия Котикович

Why the ROSETTA Spacecraft Had to Die

ESA/Rosetta/MPS for OSIRIS Team

The Rosetta orbiter's final resting place

SLOW-MO SUICIDE

By Sarah Fecht

Rest in peace, Rosetta. The comet-chasing European spacecraft descended to its death this morning in a controlled crash, after a two-year mission to explore a duck-shaped comet as it approached the sun.

Despite the Philae lander's botched landing in 2014, the Rosetta mission's orbiter went on to accomplish great things, and this morning it gave the mission the soft landing originally intended for Philae. The orbiter touched down at a nice and easy pace of about two miles per hour.

https://twitter.com/ESA_Rosetta/status/781825101113200640/photo/1

‏@ESA_Rosetta

From #67P with love: a last image, taken 51 metres before #CometLanding #MissionComplete http://ow.ly/lbmc304IADE 

European Space Agency scientists knew they would have to pull the plug sometime. Rosetta's job was to monitor changes in Comet 67P/Churyumov-Gerasimenko as its orbit brought it closer to the sun, heating it up and causing gas and dust to poof off. Now the comet's path has brought it away from the sun and it's getting colder and darker. Rosetta's solar panels were no longer getting sufficient sunlight to keep the spacecraft warm and powered-up enough to function. Communications were also becoming more difficult.

Battered from comet dust and radiation, and running low on the fuel that would keep it in orbit, Rosetta's death dive provided a treasure trove of new data about the comet. The slow-motion plummet allowed Rosetta to sample gas and dust closer to the surface than ever before, and onboard cameras snapped pictures of the "goose bumps" lining the pits in the region of Rosetta's final resting place. These 3-foot-wide lumps are believed to be the remains of the gunk that clumped together to form the comet back in the early days of the solar system.

Rosetta crash-landed in a 430-foot-wide pit known as Deir el-Medina. It sent back its last photograph from a distance of about 167 feet.

https://twitter.com/ESA_Rosetta/status/781825922647355392/photo/1

‏@ESA_Rosetta

#MissionComplete #CometLanding

Rosetta's signal was lost on impact.

To date, scientists have only sorted through about five percent of all the data from the ROSINA instrument, which measured the composition of the comet's surroundings. So although the mission is over, we'll still be learning about Rosetta's findings for months to come.

четверг, 29 сентября 2016 г.

Phil Baran finds simple recipes for complex molecules

Chemist Phil Baran draws on artistry and creativity to efficiently synthesize molecules that could improve people’s lives.

Chemist’s philosophy is to closely mimic how molecules are produced in nature

Phil Baran, 39
Chemist
Scripps Research Institute

This is not chemist Phil Baran’s first rodeo: It’s clear that he has done media interviews before. In his Scripps Research Institute office perched above a golf course along the Pacific Ocean in La Jolla, Calif., he is at ease, helpful and patient answering basic questions — why is it important to develop a new way to make a carbon-carbon bond? — as well as opining about how chemists would be better off going after more private research funding, why mentorship is still the best model for science training and his sense that the public (unjustly) thinks of chemistry as a bad word. People take for granted the many products that we rely on every day, he says. At 39, Baran is still young but already experienced and accomplished enough (he has been a tenured professor with his own lab for more than a decade) to be wary of the breathless attention journalists and prizes can bring.

That attention has come in many forms, notably a MacArthur Fellowship (worth $625,000) in 2013 and more than a dozen other awards, the most recent one from the New York Academy of Sciences. He’s been featured in write-ups in Forbes, Chemical & Engineering News, Chemistry World magazine and The Scientist, among others. He travels often, consulting with a long list of Big Pharma companies. His lab has a blog,Open Flask, and he has cowritten an e-textbook aimed at research chemists. He is frequently mentioned on organic chemistry insider blogs and appears to have his own devoted internet troll (a sure sign of fame). He has even been featured in a local fashion shoot for Modern Luxury. Reporters often call him for comments on other people’s work. But when I met him in his office this summer, he didn’t dwell on any of this.

What Baran wants to talk about is chemistry. “Phil is extraordinarily passionate about his science,” says Andrew G. Myers, a synthetic chemist at Harvard University. “It is clear that he is driven by his love of chemistry.”
Baran’s specialty is designing sophisticated chemical routes to concoct large, complex molecules from scratch, or from commercially available starter materials. It’s like cooking, but much more precise and finicky. His field, known as total synthesis, largely targets natural molecules first isolated from plants or other organisms. Such molecules are used in everything from fragrances and flavorings to pesticides, and they are hugely important in the drug development pipeline.
Most such molecules are easier and cheaper to extract from their natural sources than to make in the lab. But in some cases the plants might be rare (as was the case with the Pacific yew tree that produces the anticancer drug Taxol) or yield small amounts insufficient even for testing. Synthetic techniques also enable scientists to create closely related derivatives of a natural molecule, which may prove more useful than the original. A few decades ago, total synthesis targeted natural molecules as a tour de force of pure chemical prowess, earning accolades and advancing techniques but concocting pathways too complicated and costly to be practical. Baran’s work represents a shift in the field.
“I’m less interested in proving that something can be made chemically,” Baran says. “We want to invent new chemistry that will be useful.”
The lab is Baran’s element. It’s a calling, he says, what he can’t wait to get back to. “I have always found playing with chemicals an escape of sorts,” he says. He doesn’t recall ever being that interested in science as a child, and was not a motivated student until he found science as a high school sophomore, taking an astronomy class at a local community college in Florida, where he grew up. While simultaneously earning his high school diploma and an associate’s degree, and working long hours at Friendly’s, he took high school chemistry, where his teacher indulged his interest in reactions by letting him drop in to the lab and do experiments. “I liked mixing things and making new forms of matter. It was really cool,” Baran says.
As an undergraduate, he studied with chemist David Schuster at New York University, where he would spend long hours in the lab, and chemistry became more important to him than breathing oxygen, he says. “There was no end goal. I was more like an artist.” He did, however, become fluent in the language of molecules. From there, he got a spot in the Ph.D. program at Scripps, where he worked in the lab of synthetic chemist K.C. Nicolaou, a giant in the field. “I was an animal,” Baran says. “I had a singular purpose.” It wasn’t until his third or fourth year of graduate school that he even went to the beach.
Earning his doctorate at 24, he did a postdoc with another star of organic synthesis, E.J. Corey, a Nobel laureate at Harvard. “As a graduate student, you get paid to play in the sandbox, essentially. You are starting to correlate reality with your imagination,” Baran says. “But as a postdoc, you have real responsibility. You have to translate ideas in your head to things in the hood.”
That responsibility jumped again when, at age 25, Baran returned to Scripps to run his own lab. “It’s exhilarating and also terrifying.” Managing and funding a team, and dealing with not just your own lab failures but other people’s, that was new and challenging to someone who had lived for the chemistry itself. Now, the focus is on “sustaining the momentum,” Baran says. “I’m constantly thinking about what’s next.”
He claims he works less now than he once did, but he’s still at the lab 12 hours a day during the week, and half a day on Saturday. Surrounded by drawings made by his three young children, an old-fashioned candy dispenser filled with jelly beans and a sleek black desk, he prints out just a few of his team’s recent papers.Science, Nature, Science. A whiteboard covers the wall across from his desk — it’s littered with drawings of chemical structures, reaction designs as well as cartoons, including one of a Santa Claus the size of a fire hydrant. None of this hides Baran’s intensity. “His productivity is nothing short of remarkable,” Myers says.
Many of his team’s more than 100 papers describe quicker routes to synthesizing a molecule. He and colleagues have cooked up ingenol, a molecule whose derivatives have antitumor potential, in 14 steps and were among the first to synthesize the technically complex palau’amine in 25.
Baran does this by a kind of high-risk, fearless approach to reactions, says his postdoc Joel Smith — instead of designing elaborate chemical routes filled with detours, added to protect one part of a molecule while changing another, for example, he looks for more direct paths. “He’s looking for something creative, what he calls ‘powerful,’” says Smith, who has been working on making thapsigargin, an intimidating-looking molecule made previously in a 42-step synthesis, in a new 11-step protocol.

Phil Baran and his team found a way to synthesize the molecule phorbol in 19 steps, rather than the more than 40 typically required.

P. BARAN

In another example, Baran’s team found a new way to make phorbol, a molecule chemists have known about for more than 80 years. For the last 40 years, they’ve struggled to build it efficiently. Last April in Nature, Baran’s group reported a route that would create the complex molecule in just 19 steps — a huge improvement over the 40 to 52 steps scientists had needed before. Like most products first isolated from plants or other natural sources, phorbol is gangly, a jungle gym of a molecule with a basic structure of carbon dotted with other chemical groups, and (to a synthetic chemist) a disturbing number of oxygens in inconvenient spots. But molecules related to phorbol are of great interest to pharmaceutical companies.
Drawing inspiration from biological systems, Baran’s team relied on a new strategy, based on a two-step technique used to successfully synthesize ingenol in 2013. It involves first building the carbon skeleton (in phorbol’s case, that’s 20 atoms) and then adding the oxygens — mimicking the way that natural enzymes build the molecule within plants. The result still doesn’t compete with natural product isolation in terms of yield, but the strategy will be helpful for creating related molecules.
His philosophy, outlined in 2010 in a well-known Journal of Organic Chemistry paper on what he and coauthor Tanja Gaich call “ideality,” is to hew closely to the way that nature makes molecules. Sometimes this means recombining older techniques in new ways or inventing new chemical strategies. In January inScience, for example, he reported on a new technique to add “spring-loaded” carbon-carbon and carbon-nitrogen bonds to certain kinds of ringed molecules important for drug discovery. In May, also in Science, Baran’s team described a way to use alkyl carboxylic acids, cheap starting materials that are easy to work with, to introduce new carbon-carbon bonds to complex molecules.
Baran says he wants to choose targets for synthesis that have the most potential to help people, which is why so much of his work is now done in collaboration with companies like Pfizer, Bristol-Myers Squibb and the Danish firm LEO Pharma. Like many in his field, he’s drawn to solving real-world problems. But it’s also obvious that Baran finds the creativity of synthetic chemistry the biggest draw. “Total synthesis is a venture into partly unknown territory,” he says. “It’s like building a house while trying to juggle and play chess in 15 dimensions all at the same time.”

Citations

S. Kawamura et al. Nineteen-step total synthesis of (+)-phorbol.Nature. Vol. 532, April 7, 2016. doi:10.1038/nature17153.
T. Gaich and P.S. Baran. Aiming for ideal synthesis.The Journal of Organic Chemistry. Vol. 75, June 2010, p. 4657-4673. doi: 10.1021/jo1006812.
R. Gianatassio et al. Strain-release animation. Science. Vol. 351, Jan. 15, 2016, p. 241-246. doi: 10.1126/science.aad6252.
T. Qin et al. A general alkyl-alkyl cross-coupling enabled by redox-active esters and alkylzinc reagents. Science. Vol. 352, May 13, 2016. doi: 10.1126/science.aaf6123.

среда, 28 сентября 2016 г.

Models - 3

Алеся Кафельникова

Sara Sampaio