Category for science

Friday Science Spree 09/13/13

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Friday Science Spree 09/30/11

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Friday Science Spree 09/23/11

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Friday Science Spree 09/16/11

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Friday Science Spree 09/09/11

As always, leave your links in the comments!

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Friday Science Spree 09/02/11

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Chemical Information?

“A month in the laboratory can often save an hour in the library.”
Frank H. Westheimer

A wealth of information exists outside of Google, although both Google and Google Scholar are powerful tools. How do you search for chemistry related information, documents, references, and other literature?

What if you wanted…

  1. to find references related to your current laboratory experiment?
  2. to find references for your writing assignments?
  3. to find references for your research?
  4. to determine if the ‘science’ you are interested in pursuing is already known?
  5. to cultivate new research or project ideas?

Chemical Databases

Many databases exist that allow searching by author, keyword, title, structure, or even reaction! Most provide tools for exporting search results to text files, word docs (or rtf’s), or reference managers (e.g., RefWorks). The library maintains a current list of major resources. Those that I use most often follow (in no particular order):

  1. American Chemical Society (ACS) Publications (pubs.acs.org)
  2. Article1st and WorldCat (search journals and books, respectively – not chemistry specific)
  3. SciFinder Scholar + structure searching (ChemAbstracts search client)
  4. Reaxys + structure/reaction searching
  5. ScienceDirect (not chemistry specific)
  6. Cambridge Crystallographic Data Center (ConQuest – crystal structure search)
  7. Google Scholar (not chemistry specific)

Be careful…

Do not assume that each of these databases is comprehensive! As much as they would like to be the “one stop shop,” each will have omissions or exclusions of some sort. A good strategy is to use multiple searches of multiple databases. Also remember that a single search term is unlikely to provide comprehensive results. Small changes (additional terms, change in case, etc.) may give drastically different results. Remember to always put your search results in context with the ultimate question(s) asked, and that smaller, complementary searches are usually better than attempting one world beating search!

Searches to try… (use multiple databases as appropriate)

Author

  1. DeSimone, Joeseph
  2. Sorensen, Eric
  3. Trofimenko, S.
  4. Rabinovich, Daniel
  5. Riordan, C.

Topic

  1. organometallic (complex)
  2. olefin metathesis
  3. oxidation
  4. olefin oxidation
  5. epoxidation (styrene)
  6. asymmetric oxidation
  7. trispyrazoylborate (synthesis)

Structure

  1. Search using a simple ethylenediamineNi(II) fragment
  2. Search for both nitrito and nitro cobalt complexes, and other metal nitrito/nitro complexes
  3. Consider the salen ligand and derivatives
  4. Consider a fragment of the tris(pyrazolyl)borate ligand using different R groups (e.g., Me, t-Bu, Ph, halogens… use your imagination)

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Friday Science Spree 08/27/10

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Friday Science Spree 02/05/10

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It’s about time to…

It’s about time to throw some credibility to fans of the 2012 apocalypse theory. There is a lot of talk of ancient Mayan calendars, interstellar collisions, and terrestrial polar shifts and while there is minimal scientific relevance to these claims, one cataclysmic event is likely to occur in the next several years. A supernova. Betelgeuse, a star in the Orion constellation is a first magnitude super giant. The size of a star is one of the most important intrinsic features. Bigger stars form faster, live shorter, and die more explosively. Super giants are the last step in a star’s evolution.

All stars start out using hydrogen as nuclear fuel. This hydrogen is fused together to form helium in a very explosive nuclear reaction that “powers” the star. As the hydrogen runs out, the star begins to collapse from a lack of radiative pressure from the core. The collapse of this much mass increases the temperature until the core is hot enough for Helium fusion. This process is repeated as the fuel continues to be consumed, from hydrogen to helium, helium to carbon, carbon to silicon, and silicon to iron. It is at this point that the already explosive reactions become even more cataclysmic. All of the previous fusion reactions release energy, but an iron fusion reaction actually requires energy. This process reverses the radiation pressure which causes a irreversible pull towards the center of mass. At its most compressed state, all electrons in the star are compressed into contact with the nucleus against the strong force. The resulting rebound causes one of the most powerful explosions in the universe a supernova.

Since Betelgeuse is near the end of its life as a super giant it is due to supernova in the next several years. When this happens, the resulting explosion will be approximately 10,000 times brighter than our sun, though it will be very distant. The supernova will last for several months, up to even a year. The brightness will block out every star in the night sky and will even be brighter than the moon. It will even be visible in the daytime. The extreme distance will limit any detrimental effects here on Earth (whether it be radiation or charged particles), preventing any poorly done future Hollywood movies. It won’t end the world, but having two suns in the sky will sure look cool.

See Also: http://stars.astro.illinois.edu/sow/betelgeuse.html

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Friday Science Spree 01/29/10

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Friday Science Spree 01/22/10

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Controversial Fat Injections to Improve Breast Reconstruction. Is Beauty Worth the Risks?

womanbraALY_450x413wOne’s breast shape may not always be as perfect as those seen in the Victoria Secret catalogue; however, when you’re paying $10,000.00 for them, they better come pretty darn close. Many doctors are toying with the controversial issue of using fat injections to fix unexpected and uncontrollable errors in breast augmentation such as dimpling, wrinkles, or unsymmetrical contouring. Proponents claim fat injections make breasts softer, smoother, and more natural looking. Another appealing aspect of fat injections is that doctors use the patients’ own fat deposits found in commonly unflattering areas like the thighs and stomach. “Patients were uniformly satisfied with the results, as well as the side benefit of abdominal ‘liposuction’,” said Gregory R. Scott, MD, a plastic surgeon with Kaiser Permanente Medical Center, San Diego, California.

The allure of this procedure is dramatically curtailed when one thinks about the risks such as infection, and the amount of healing time needed. The American Society of Plastic and Reconstructive Surgeons (ASPRS) strongly condemns the use of fat injections for breast enlargement, warning that the procedure may hamper the detection of early breast cancer. This is because the fat can calcify and interfere with mammogram results, causing it to be mistaken as cancerous tissue. Also, benign palpable cysts can form in the field of the fat transfer, potentially causing more shape deformity. A 1998 Journal of Japan Society of Aesthetic Surgery article on lipo-injection induced tumor (LIT), reported that 24 cases of LIT were diagnosed between April, 1996 and April, 1998. It is also uncertain how much fat is required to adequately reshape the breast or how much of that fat will be absorbed by the body. The ASPRS cautions that fat injections may offer only temporary benefits as the fat can potentially die, causing scar tissue in the area of injection. It is estimated 70% of the fat is absorbed by the body after six months; thus, those who decide to have the procedure should be aware that injections must be repeated regularly to maintain the desired result. Fat is absorbed if it does not develop its own blood supply; however, if the fat does develop a blood supply, it becomes a living tissue and can grow if a patient gains weight or shrink if she loses weight. In a study conducted with 42 patients, the amount of fat transferred to the breast ranged from 30 to 180mL, suggesting this procedure may not even be possible for patients without adequate available fat.

We are faced with the issue of artificial enhancements. Is the quest for beauty really worth the risk? In 2007, alone, there were nearly 348,000 breast augmentation procedures and more than 57,000 breast reconstructions performed. These high numbers prove that there is no breast gain without pain, which is why so many women are buying into artificial enhancements. Thus, our society’s relentless search for beauty perfection ensures that breast augmentation procedures as well as fat injection techniques will only get better with time and will likely stay in demand.

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Can traveling on airlines with liquids soon be possible?

confiscated items-wDepending on how frequently you travel, you may or may not have experienced the many inconveniences of going through airport security. Considering that I travel approximately 2200 miles to get to Villanova, I fall into the former category. One of these inconveniences is the restriction of carrying liquids onto commercial airlines. There are several techniques (e.g., nuclear magnetic spectroscopy) that could be employed to screen liquids as to whether or not they could be used as potential explosives. However, these techniques are usually too expensive or require too much time to be implemented in airports. Fortunately, a BBC article is reporting that German scientists have developed a quick technique that could be used to test for potentially dangerous liquids, thus making the ban on carrying liquids through airport security unnecessary. The proposed technique is called Hilbert spectroscopy and involves using a very wide spectrum of light to identify liquids that could be mixed to form an explosive or that have already been mixed. When baggage is X-rayed in airport security, measurements are usually confused by the packaging and other items inside the bag. The new technique manages to get around this problem by using the wider range of frequencies.

“The trick, they say, is to use a “nanoelectronic” device known as a Josephson junction. This allows the frequencies of light reflected from a sample to be quickly added up. This in turn provides a chemical “fingerprint” of the item being analyzed.”

The key advantage of using the Josephson junction is that it spans the low and high frequency ranges covered by significantly more expensive devices. The scientists responsible for the new technique have conceded that further developments are necessary to refine their approach but they are confident that the technique can be applied to security screening. If this technique is implemented, frequent travelers may be spared one less inconvenience. I, for one, would very much like to see this technique widely adopted.

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Greenhouse gases and arctic methane hydrate

methane hydrateWith all the focus on global warming and greenhouse gases the question becomes how much of it has been caused by humans? NOAA researchers have discovered a large source of methane in the Arctic Ocean floor. Methane is a greenhouse gas that has been found to be close to 25 times more effective at trapping heat than carbon dioxide. This newly discovered source is just north of Norway and methane is constantly bubbling up from the ocean floor. Researchers say that a gradual warming of the regional ocean current has caused the temperature sensitive methane hydrate to break down and discharge gas from the seabed.

Methane hydrate typically forms beneath the seabed and is stable at depths below 300 meters. Scientists have collected sonar images of at least 250 plumes of methane gas rising from the ocean floor; these plumes are especially concentrated in the portion of the Gulf Stream that moves Atlantic seawater to the Arctic Ocean. This area has warmed by about 1 degree Celsius over the past 30 years causing the a decrease in the depth where hydrate is stable to 396 meters. It is believed that glacial cycles have been driven by hydrate formation and disintegration, and the resultant released methane in the atmosphere triggered climate-feedback effects. As our ability to study the ocean has grown, researchers have documented about 90 different oceanic locations of methane hydrate that are estimated to contain as much as 63,000 gigatons or more of carbon.

Similar methane deposits have been found in the ocean surrounding northern Alaska. There, scientists have paired with Coast Guard Arctic flights using a C-130 maritime surveillance aircraft. Since 2007 these flights have been carrying air-sampling instruments on the twice-monthly flights out of Kodiak over the Brooks Range to Barrow in the Arctic Circle. One of the airplane windows was replaced with an air inlet that is connected to onboard instrumentation that measures greenhouse gases and ozone in real time. These air samples are also stored and later analyzed in a lab in Boulder. Hopefully, this analysis will give scientists more insight into the distribution of many pollutants and trace gases.

Could this natural source of methane be a root cause of global warming?

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The second law isn’t just slowly killing you in PChem, but slowly killing the universe…

Black-holeThe second law of thermodynamics states that the entropy of the universe is increasing. Black holes contribute to the entropy of the universe by breaking down matter into more disordered states. Previous studies on a black hole’s effect on the entropy of the galaxy have only been done on smaller black holes. Recently, Australian scientists have looked into the effects of supermassive black holes on entropy. They discovered that the previously predicted value for the effects of the supermassive black holes to be much less then what they really are. When entropy in the universe is maximized heat flow would no longer exist.

“in the case of the universe, Egan says, ‘we’d like to know [when and] if the entropy will eventuallyreach a maximum value, marking the end of all dissipative processes, including life.’ Physicists have dubbed that maximum entropy ‘heat death.’”

While the universe is closer to ‘heat death’ than previously estimated it still far from reaching its maximum entropy. Others note that if entropy is concentrated in these supermassive black holes, then the remainder of the universe should be at a lower entropy and further away from ‘heat death.’

[via usnews & world report]

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Lists of some of my science related feeds… [updated]

Chemistry journals I ‘try’ to keep up with (every two weeks or monthly):

  1. Accounts of Chemical Research | RSS
  2. Crystal Growth & Design | RSS
  3. Inorganic Chemistry | RSS
  4. Chemical Society Reviews | RSS
  5. Dalton Transactions | RSS
  6. Angewandte Chemie | RSS

And other science related feeds I review (every week or so):

  1. Cosmic Variance | RSS
  2. Innovation | RSS
  3. Next Big Future | RSS
  4. Nobel Intent | RSS
  5. Science Blogs Select | RSS
  6. Slate Magazine – Science | RSS
  7. Bad Science | RSS [update]

What are you reading online (science related of course). Leave a link and why you read it in the comments!

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Duplicating nature in the lab

If you need further justification for research, check out this piece over at wired

But although nature can make a remarkably wide variety of chemicals — far more than the best molecule-making robots — it does not always deliver them in bulk. [wired]

I especially like the conversion of cocaine to an ion-channel blocker found in poison dart frogs. Good stuff!

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