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Going

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首先预祝大家国庆小长假吃好，喝好，玩好的同时，也学好！上周二的科技贴，有看到大家留言，说科技文章好难啊，读了两遍也没有看懂~~承认确实是有些难度，不过受刺激和接受锻炼还是在阅读小分队比较好，你会发现锻炼到一定程度之后再看GMAT阅读文章，心里竟然不那么害怕啦，文章读起来也不是特别特别的难！大家加油！本次所有内容，有的Session长，有的Session短，总体算来是正常的哈，Obstacle同时作为科普给大家，Enjoy：）

Part I: Speaker

Yeast Coaxed To Make Morphine

Genetically manipulated yeast can produce morphine, which could help get around the problems with poppy crops, which include climate, disease and war. Karen Hopkin reports.

Yeast. They already participate in producing some of the most popular pain-killing substances around: beer and wine. Now, scientists have engineered yeast that can also make one of the most powerful analgesics: morphine. Their work is in the journal Nature Chemical Biology. [Kate Thodey, Stephanie Galanie and Christina D. Smolke, A microbial biomanufacturing platform for natural and semisynthetic opioids]

Opiates like morphine and codeine are essential for treating severe pain. But making these meds isn’t easy. All are derived from opium poppies, and tens to hundreds of thousands of tons are needed to meet global needs. The crops can also be affected by climate, disease and even political turmoil in the countries where the plants are grown, which further limits commercial production.

To get around these potential challenges, researchers have turned to yeast, an organism that can be grown easily on industrial scales.

The scientists inserted into yeast cells a handful of genes isolated from the opium poppy. These genes encode the enzymes the plants use to produce opiates. After tweaking the system to adjust the relative amounts of the enzymes, the researchers could feed their yeast a precursor chemical called thebaine, and get pure morphine in return.

The yeast can’t yet make opiates from scratch. But with a bit more effort and a few more enzymes, yeast may produce painkillers that are prescription-strength.

Source: Scientific America

http://www.scientificamerican.com/podcast/episode/yeast-coaxed-to-make-morphine/

[Rephrase 1, 1:29]

Going

Part II: Speed

Balancing the excitation and inhibition tightrope in depression
By Bethany Brookshire，September 25, 2014

[Time 2]
Isaac Newton famously showed that in physics, every action has an equal and opposite reaction. A similar push-and-pull of positive and negative inputs also exists in our brains. Brain cells can send out excitatory chemical signals, and they can also receive inhibitory chemical signals, putting the brakes on further signaling.

This delicate balance of excitation and inhibition allows our brains to function normally and to react to the world around us. A new study shows that the same neurons contribute excitatory and inhibitory chemical signals in a brain area linked with how we process disappointment, and that antidepressants might be able to change this delicate molecular dance and stop some of the negative thought cycles associated with depression. But while the work finds an association, it’s not yet proof that the balance of these chemicals holds the key to relieving depressive symptoms.

The study, published September 19 in Science, focuses on the lateral habenula. This tiny area makes up the “stalk” connecting the pineal gland to the rest of the brain. It receives inputs from areas of the brain important in reward and emotional processing, including the basal ganglia.

Some areas of the brain appear to specialize in predicting rewards, showing increases in activity in response to enjoyable things such as food, sex or drugs. Activity in these areas lets us know when things are about to get good. But for every high there is a low. The lateral habenula is thought to play a role in how we process negative events: Getting a lemon on the slot machine again or the empty inbox on your dating site. Studies in monkeys and other animals have shown that increased activity in the habenula is linked to depressive behaviors, and treatment with antidepressants decreases this activity. In addition, a study in rats and a 2009 case study in a human patient showed that deep-brain stimulation in the lateral habenula could relieve symptoms of depression.
[322 words]

[Time 3]
Steven Shabel, a neuroscientist at the University of California, San Diego, wanted to know how antidepressants might be changing the lateral habenula. He and his colleagues performed a series of experiments in rats and mice, targeting the neurons that send signals into the brain area. Shabel inserted light-activated protein channels into neurons heading from the reward-related areas of the basal ganglia toward the lateral habenula.  He then used a technique called electrophysiology to carefully impale single cells with a small glass pipette, gaining access to the electrically sensitive cell membrane. Shabel could then shine light onto the cell, activating the light-sensitive protein channel and causing electrically charged ions to rush into or out of the cell. The rush of ions causes chemical messengers to be released from one cell to another. With this access to the cell membrane, Shabel could hold the cell at different electrical potentials, keeping the electrical charge higher or lower than the electrical charge outside the cell. At different potentials, different amounts of ions go rushing in and out of the membrane, stimulating the release of different chemicals.

At some potentials, the cells released the excitatory signaling molecule glutamate. At others, he watched the same cell release the inhibitory signaling molecule GABA. Further studies confirmed that the same cell was releasing both excitatory and inhibitory signals into the lateral habenula.

The lateral habenula is dominated by excitatory activity, but there is a small amount of inhibitory activity that holds the excitation in check. The excitatory activity is particularly increased during times of disappointment. “The excitatory signals dominate,” Shabel notes. “The inhibitory signals appear to limit the excitation. We think in a live animal this might limit the disappointment signal.”
[283 words]

[Time 4]
Other studies have shown that the small amount of inhibitory activity decreases even further in animal models of depression. Without that small inhibitory check, the excitation overwhelms the habenula, and may lead to constant feelings of disappointment. So Shabel and his colleagues wanted to see if antidepressant treatment might alter the balance of excitatory and inhibitory signals. They administered two weeks of antidepressants to normal mice and to a rat model of depression, and found that the inhibitory signals to the lateral habenula increased.

“It’s known that antidepressants can reduce people’s processing of negative events,” Shabel says. “So we think this might be one mechanism for how they do that.” If higher activity in the habenula is a sign of increased experience of negative events, increasing inhibition to that area could help combat some of the symptoms of depression. But Shabel cautions “there are a lot of experiments that still need to be done.”

Thomas Hahn, a computational neuroscientist at the Bernstein Center for Computational Neuroscience in Mannheim, Germany, notes that the methods were “expertly done.” But he cautions that while the study shows the signals coming into the lateral habenula from reward-related areas, it doesn’t show anything going out. Without data coming out of the habenula, Hahn notes, it’s impossible to tell how the inputs are affecting the area. “One should not forget that the lateral habenula gets numerous other inputs,” he says. “So it’s not clear that a bit more [inhibitory signaling] would do the job” of controlling all the inputs going in to the area.

And while the study shows that antidepressant treatment can change the excitatory and inhibitory balance, it does not show what effect this has on behavior. While the authors did use doses of antidepressants that have been effective in other animals and in other laboratories, they didn’t do any behavioral studies of depressive behavior to go with their studies of the habenula. Catherine Belzung, a neuroscientist at the University of Tours in France, says that while the paper is “certainly important,” without behavior or depression-related biomarkers, “the data presented are not causal.”

Shabel says his next goal is to “look at disappointment in rodents, to see if the pathway is affecting behavior. The idea is then to look at whether antidepressants do decrease the responses in the habenula, and how that affects the animal’s behavior.” If the behavioral studies are promising, he hopes that eventually scientists might find drugs that specifically alter activity in habenula to treat depression. But in the meantime, more studies are needed to understand the delicate chemical push and pull that underlies how we experience life’s disappointments.
[439 words]

Source: Science News
https://www.sciencenews.org/blog/scicurious/balancing-excitation-and-inhibition-tightrope-depression

Gut bacteria may prevent food allergies

Microbes block food from seeping into bloodstream, mouse study shows
by Meghan Rosen,August 26, 2014

[Time 5]
Peanuts can drive people’s immune systems nuts, but gut microbes could offer some protection. Mice harboring Clostridia bacteria in their guts are less sensitive to the notoriously allergenic legumes than mice without the microbes, researchers report August 25 in the Proceedings of the National Academy of Sciences.

For years scientists have suspected that some gut bacteria curb food allergies, and that killing these good guys could bring trouble. But no one knew which microbes helped or how exactly they worked.

Cathryn Nagler of the University of Chicago and colleagues treated some mice with antibiotics to wipe out the animals’ gut bacteria, and then triggered an allergy-like response to peanut particles. Peanuts revved up the germ-free animals’ immune systems — but mice with normal gut bacteria didn’t have the bad reaction.

Giving germ-free mice a dose of Clostridia bacteria made the animals more like their counterparts with normal gut flora. The microbes encourage mouse cells to make mucus that helps seal up the intestines, keeping food particles from slipping into the bloodstream and riling up the immune system, the researchers found.

Humans also harbor Clostridia, so boosting these bacteria’s numbers with probiotics — living cultures of bacteria in yogurt and other foods — may help prevent or treat food allergies in people, Nagler’s team suggests.
[211 words]

Source: Science News
https://www.sciencenews.org/article/gut-bacteria-may-prevent-food-allergies

Recovery time from surgery foretold
Presence of certain immune cells suggests easy return to health
by Nathan Seppa, September 24, 2014

[Time 6]
Blood samples taken from patients after surgery might reveal who is destined for a quick rebound, Stanford University researchers report in the Sept. 24 Science Translational Medicine. A comparison of 32 people, with an average age of 60, recovering from a hip replacement found that an immune-cell “signature” might predict a patient’s recovery course.

The immune system responds to surgery as it would to any trauma. First-responder cells called monocytes rush to the scene, triggering inflammation. But too much inflammation slows recovery. While combing through blood samples taken after surgery, the researchers noticed that certain versions of cells called CD14+ monocytes seemed to contribute to a better recovery. In patients who ended up recovering quickly, these cells limited the activity of three molecules broadly associated with inflammation within the first 24 hours after surgery.

Many factors probably underlie the variability in recovery time among surgery patients, and coauthor Martin Angst, an anesthesiologist, says the cell signature analysis can explain about half of the puzzle. It was able to predict which patients were bound for good recoveries — with less fatigue, pain or functional impairment — only 40 to 60 percent of the time.
[191 words]

Source:Science News
https://www.sciencenews.org/article/recovery-time-surgery-foretold

Going

Part III: Obstacle

Top 10 things you might not know about stars
By Larry Sessions in BLOGS | SPACE on Sep 18, 2014

[Paraphrase 7]
Here’s a collection of 10 unexpected, intriguing facts about the stars of our universe – including our sun – that you probably didn’t know!

1. Every star you see in the night sky is bigger and brighter than our sun. Of the 5,000 or so stars brighter than magnitude 6, only a handful of very faint stars are approximately the same size and brightness of our sun and the rest are all bigger and brighter. Of the 500 or so that are brighter than 4th magnitude (which includes essentially every star visible to the unaided eye from a urban location), all are intrinsically bigger and brighter than our sun, many by a large percentage. Of the brightest 50 stars visible to the human eye from Earth, the least intrinsically bright is Alpha Centauri, which is still more than 1.5 times more luminous than our sun, and cannot be easily seen from most of the Northern Hemisphere.

2. You can’t see millions of stars on a dark night. Despite what you may hear in TV commercials, poems and songs, you cannot see a million stars … anywhere. There simply are not enough close enough and bright enough. On a really exceptional night, with no Moon and far from any source of lights, a person with very good eyesight may be able to see 2000-2500 stars at any one time. (Counting even this small number still would be difficult.). So the next time you hear someone claim to have seen a million stars in the sky, just appreciate it as artistic license or exuberant exaggeration – because it isn’t true!

3. Red hot and cool ice blue – NOT! We are accustomed to referring to things that are red as hot and those that are blue as cool. This is not entirely unreasonable, since a red, glowing fireplace poker is hot and ice, especially in glaciers and polar regions, can have a bluish cast. But we say that only because our everyday experience is limited. In fact, heated objects change color as their temperature changes, and red represents the lowest temperature at which a heated object can glow in visible light. As it gets hotter, the color changes to white and ultimately to blue. So the red stars you see in the sky are the “coolest” (least hot), and the blue stars are the hottest!

4. Stars are black bodies. A black body is an object that absorbs 100 percent of all electromagnetic radiation (that is, light, radio waves and so on) that falls on it. A common image here is that of a brick oven with the interior painted black and the only opening a small window. All light that shines through the window is absorbed by the interior of the oven and none is reflected outside the oven. It is a perfect absorber. As it turns out, this definition of being perfect absorbers suits stars very well! However, this just says that a blackbody absorbs all the radiant energy that hits it, but does not forbid it from re-emitting the energy. In the case of a star, it absorbs all radiation that falls on it, but it also radiates back into space much more than it absorbs. Thus a star is a black body that glows with great brilliance! (An even more perfect black body is a black hole, but of course, it appears truly black, and radiates no light.)

5. There are no green stars. Although there are scattered claims for stars that appear green, including Beta Librae (Zuben Eschamali), most observers do not see green in any stars except as an optical effect from their telescopes, or else an idiosyncratic quirk of personal vision and contrast. Stars emit a spectrum (“rainbow”) of colors, including green, but the human eye-brain connection mixes the colors together in a manner that rarely if ever comes out green. One color can dominate the radiation, but within the range of wavelengths and intensities found in stars, greens get mixed with other colors, and the star appears white. For stars, the general colors are, from lower to higher temperatures, red, orange, yellow, white and blue. So as far as the human eye can tell, there are no green stars.

6. Our sun is a green star. That being said, the sun is a “green” star, or more specifically, a green-blue star, whose peak wavelength lies clearly in the transition area on the spectrum between blue and green.  This is not just an idle fact, but is important because the temperature of a star is related to the color of its most predominate wavelength of emission. (Whew!) In the sun’s case, the surface temperature is about 5,800 K, or 500 nanometers, a green-blue. However, as indicated above, when the human eye factors in the other colors around it, the sun’s apparent color comes out a white or even a yellowish white.

7. Our sun is a dwarf star. We are accustomed to think of the sun as a “normal” star, and in many respects, it is. But did you know that it is a “dwarf” star? You may have heard of a “white dwarf,” but that is not a regular star at all, but the corpse of a dead star. Technically, as far as “normal” stars go (that is, astronomical objects that produce their own energy through sustained and stable hydrogen fusion), there are only “dwarfs,” “giants” and “supergiants.” The giants and supergiants represent the terminal (old age) stages of stars, but the vast majority of stars, those in the long, mature stage of evolution (Main Sequence) are all called “dwarfs.” There is quite a bit of range in size here, but they are all much smaller than the giants and supergiants. So technically, the sun is a dwarf star, sometimes called “Yellow Dwarf” in contradiction to the entry above!

8. Stars don’t twinkle. Stars appear to twinkle (“scintillate”), especially when they are near the horizon. One star, Sirius, twinkles, sparkles and flashes so much some times that people actually report it as a UFO. But in fact, the twinkling is not a property of the stars, but of Earth’s turbulent atmosphere. As the light from a star passes through the atmosphere, especially when the star appears near the horizon, it must pass through many layers of often rapidly differing density. This has the effect of deflecting the light slightly as it were a ball in a pinball machine. The light eventually gets to your eyes, but every deflection causes it to change slightly in color and intensity. The result is “twinkling.” Above the Earth’s atmosphere, stars do not twinkle.

9. You can see 20 quadrillion miles, at least. On a good night, you can see about 19,000,000,000,000,000 miles, easily. That’s 19 quadrillion miles, the approximate distance to the bright star Deneb in Cygnus. which is prominent in the evening skies of Fall and Winter. Deneb is bright enough to be seen virtually anywhere in the Northern hemisphere, and in fact from almost anywhere in the inhabited world. There is another star, Eta Carina, that is a little more than twice as far away, or about 44 quadrillion miles. But Eta Carina is faint, and not well placed for observers in most of the Northern hemisphere. Those are stars, but both the Andromeda Galaxy and the Triangulum Galaxy are also visible under certain conditions, and are roughly 15 and 18 quintillion miles away! (One quintillion is 10^18!)

10. Black holes don’t suck. Many writers frequently describe black holes as “sucking” in everything around them. And it is a common worry among the ill-informed that the so-far hypothetical “mini” black holes that may be produced by the Large Hadron Collider would suck in everything around them in an ever increasing vortex that would consume the Earth! “Say it ain’t so, Joe!” Well, I am not Shoeless Joe Jackson, but it ain’t so. In the case of the LHC, it isn’t true for a number of reasons, but black holes in general do not “suck.”
This not just a semantic distinction, but one of process and consequence as well. The word “suck” via suction, as in the way vacuum cleaners work, is not how black holes attract matter. In a vacuum cleaner, the fan produces a partial vacuum (really, just a slightly lower pressure) at the floor end of the vacuum, and regular air pressure outside, being greater, pushes the air into it, carrying along loose dirt and dust.
In the case of black holes, there is no suction involved. Instead, matter is pulled into the black hole by a very strong gravitational attraction. In one way of visualizing it, it really is a bit like falling into a hole, but not like being hoovered into it. Gravity is a fundamental force of Nature, and all matter has it. When something is pulled into a black hole, the process is more like being pulled into like a fish being reeled in by an angler, rather than being pushed along like a rafter inexorably being dragged over a waterfall.
The difference may seem trivial, but from a physical standpoint it is fundamental.
So black holes don’t suck, but they are very cool. Actually, they are cold. Very, very cold. But that’s a story for another time.
[1544 words]

Source: Earth Sky
http://earthsky.org/space/ten-things-you-may-not-know-about-stars

MAGGIEHE1993

沙发耶~~~~~~~~~~~~~
谢谢going棒棒的文章~~~ 涨姿势了有木有~~~~~~~~
--------------------------------------------
Obstacle: 10 things you might not know about stars
          Every star you see in the sky is bigger and brighter than our sun.
          You can't see millions of stars on a dark night.
          In fact the stars appear to be red are the coolest and the stars appear to blue are the hottest.
          Stars are black bodies which absorbs 100 percent of all electromagnetic radiation that falls on it.
          There are no green stars because our human eyes tend to mix different colors of lights.
          Our sun is a green star because its surface temperature allows it to radiate green-blue light.
          Our sun is a dwarf star.
          Stars don't twinkle. Yet they appear to twinkle is because the effect of our earth atmosphere.
          You can see 20 quadrillion miles at least because stars that are so far away from us radiate lights that can
          be seen by us.
          Black holes don't suck.

TINGYI-2014

3'24 2'07 2'07  3'07 2'04 2'09  12'59
Very interesting contents! Thank you!

古月小破烂

time 2 2’26
       reaction of brain about good thing or bad. opposite reaction.
time 3 2’13
        use mice and rats to do the experiment, and get result that the same cell release both excitatory and inhibitory signal.
time 4 3’08
         experiment about if antidepressant treatment alter the balance
         result that it can influence rat but still need further research
time 5 1’30
         test about peanut and gut microbe prevent the food allergies.
time 6 1’15
          during surgery and see problem
obstacle 9’16
          10 things about star we don’t know before

soun0218

T2: 4:02
Brain cells can send out the chemical signals and also receive the positive and negative chemical signals.
There is a subject called h could send out the negative chemical signals and stimulate the behavior of people.

T3: 3:05

T4:4:14
The other subject can cause the antidepression

T5:2:47
Some people found that gut bacteria is bad for our immune system, but according to recent experiment, gut bacteria can prevent food allergy.

T6: 1:58
A immune cell called signature can predict the recovery time of people.

O1: 10:49
The article indicates 10 things we don`t know about the stars, such as stars color and size, observation distance, black hole, ect.

AXIXI

[Time2-- 1:51] The balance of excitation and inhibition in brains linked with depression. Studies in monkeys and human patients showed that the activity in habenula is linked to depressive behaviors.
-----------------------------------
[Time3--2:04 ] Steven Shabel performed several experiments and concluded that the same cell was releasing both excitatory and inhibitory signals into the lateral habenula.
-----------------------------------
[Time4--3:14 ] The studies show that antidepressants can reduce the creatures' depression. But more further studies are needed to understand that how chemical antidepressants effect animal's behavior.
-----------------------------------
[Time5-- 1:44] A study about mibrobes that curb food allergies might help peple prevent food allergies.
-----------------------------------
[Time6--1:23 ] A study found that cells called CD14++ monocytes help patients to a better recovery.
-----------------------------------
[Obstacle--10:10 ] There are 10 unexpected ideas about the stars.
1. Every star is much bigger and brighter than our sun.
2. The visible stars in dark night may be 2000-2500 stars, not millions of stars.
3. The red stars are cooler than the blue stars.
4. Stars are black bodies.
5. As far as the human eye can tell, there are no green stars.
6. Our sun's color comes out a white or a yellowish white, but actually our sun is a green star.
7. Sun is a dwarf star.
8. Stars do not twinkle.
9. We can see 20 quadrillion miles.
10. Black holes do not suck, but has a very strong gravitational attraction.

-----------------------------------

sufangfang27

Thank you very much!
--------------------------------
10.1
Speed
time2.3.4
01.57.95
01.46.66
02.49.32
160w/m
"A famous theory:every action has an equal and opposite reaction
A new experiment focus on two opposite way of depression:conclusion→detailed experiment.
Other experiment in this field.
Futher direction of the study:in disappointment"

time5
01.32.08
140w/m
"Gut bacteria may prevent food allergies
result-experiment procedure-advice"

time6
01.15.98
152w/m
"an immune-cell “signature” might predict a patient’s recovery course
introduce the topic→procedure→conclusion"

Obstacles
10.16.29
150w/m
"Top 10 things you might not know about stars
those 10 things are all well concluded in the first sentence of each paragragh.
"

丝袜奶茶

just several people are ahead of me, not dozen people.
Guess I'm ahead of the game.lalalalalala
time 2 3 4
Thesis: discuss if people can use  inhibitory to ease bubenula
strucuture: background about brain function-habenula triggers depression-ways to test it(ion membrace stimulate different chemical)-inhibitory may solve the problem-quastionaire about the new method
time 5 0122
some bateria in guts can lower the allergy rate
time 6 0200
cell associalte with the inflammation, which can make the patient recovery sooner
obstacle: 0800
10 things about stars.
man, you need to talk with my buddy Hawkins about black hole DON"T suck