He was asked by a Time reader, "What is the most astounding fact you can share about the universe?" This beautifully edited video by Max Schlickenmeyer highlights Dr. Tyson's answer. Essentially the chemistry that created the atoms and elements of the universe is the same chemistry made us. That is how we are connected to the universe.
His eloquent response is here.
A place to post interesting links about chemical research and applications and connect them with concepts from general chemistry. Especially for students who are wondering where basic chemistry fits in.
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Friday, March 20, 2015
Wednesday, March 18, 2015
Inspiration from Worms and Mussels - A Sutureless Way to Do Surgery
Healing from surgery can be complicated by using sutures in particular parts of our bodies. Depending on the type of material (silk or polymer-based), the immune system can have a reaction, prolonging healing times to as long as 4 months!
So what is a possible alternative that can be easily applied to sensitive tissue and maintain structural integrity long enough for healing? One clever organism that bioengineers are currently studying is the sandcastle worm or Phragmatopoma californica.
Professor of Bioengineering Russell Stewart from the University of California Santa Barbara is currently studying waterproof adhesives that sandcastle worms (and caddisflies) use to create their elaborate constructions. In his research, he has determined that the forces of attraction are electrostatic (oppositely charged ions attracting each other) with some cross-linking between catechol and DOPA polymers.
Articles and Resources of Interest:
*A Blood-Resistant Surgical Glue for Minimally Invasive Repair of Vessels and Heart Defects; by N. Lang, M.J. Pereira, Y. Lee, I. Friehs, N.V. Vasilyev, E.N. Feins, K. Ablasser, E.D. O'Cearbhaill, C. Xu, A. Fabozzo, R. Padera, S. Wasserman, F. Freudenthal, L.S. Ferreira, R. Langer, J.M. Karp, and P.J. del Nido
*Letting Bio-Inspired Solutions Evolve : Q &A with Jeff Karp
So what is a possible alternative that can be easily applied to sensitive tissue and maintain structural integrity long enough for healing? One clever organism that bioengineers are currently studying is the sandcastle worm or Phragmatopoma californica.
By Fred Hayes for the University of Utah [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
Sandworms are typically shy creatures, coming out only to catch microorganisms and grain particles. Their tubules can be found along Baja California and Mexico.
Professor of Bioengineering Russell Stewart from the University of California Santa Barbara is currently studying waterproof adhesives that sandcastle worms (and caddisflies) use to create their elaborate constructions. In his research, he has determined that the forces of attraction are electrostatic (oppositely charged ions attracting each other) with some cross-linking between catechol and DOPA polymers.
Inspired by the worm's ability to create an adhesive that works in water, medical doctor Nora Lang and bioengineers Maria Pereira and Jeffrey Karp at Harvard Medical School teamed up with other scientists to create an adhesive that works in vivo in repairing tiny defects in sensitive tissue.
Exposure of hydrophobic light-activated adhesive polymer (HLAA) to UV light creates crosslinking
(image from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4157752/)
Using a polymer of glycerol and sebacic acid, they exposed the molecules to UV light and created crosslinks. This resulted in a highly flexible material that could be gently applied to very small tears in a carotid artery:
In this carotid artery, a hole was created and then sealed with HLAA polymer. After 24 hours, the seal remained intact.
With its recently tested potential, light-activated liquid polymers may have a place on the surgeon's tray in place of sutures.
*A Blood-Resistant Surgical Glue for Minimally Invasive Repair of Vessels and Heart Defects; by N. Lang, M.J. Pereira, Y. Lee, I. Friehs, N.V. Vasilyev, E.N. Feins, K. Ablasser, E.D. O'Cearbhaill, C. Xu, A. Fabozzo, R. Padera, S. Wasserman, F. Freudenthal, L.S. Ferreira, R. Langer, J.M. Karp, and P.J. del Nido
*Letting Bio-Inspired Solutions Evolve : Q &A with Jeff Karp
Monday, March 2, 2015
Amazing Uses of Bubble Wrap
The next time you toss that bubble wrap from your next package, think of the possible applications for it. What else can you do with air bubbles encased in plastic?
Interestingly, when it was created in 1957 by engineers Alfred Fielding and Marc Chavannes, the original plan was to cover walls with a 3-dimensional textured pattern:
Only three years later it was discovered to be a superb packing material. Bubble wrap itself is made of low-density polyethylene (LDPE), a polymer of ethylene monomers that has some branching.
Branching around polyethylene reduces strands of it to pack closely, and this decreases its density.
More recently, other amazing uses for bubble wrap have emerged. One example is from Bradley Hart, an artist in New York who injects different colors of paint into the bubbles to create portraits and landscapes:
Is there a place for bubble wrap in a chemistry lab? Most definitely! Professor George Whitesides and colleagues from Harvard University came up with some clever applications. Because the material is so cheap (about 60 cents per square meter) and the same area can have up to 5000 bubbles, the team discovered that the bubbles can safely hold liquid samples. This lead to a number of experiments testing the reliability of these plastic bubble holders:
A bubble can act as an electrochemical cell! Here 2 carbon electrodes are used to measure the current from different concentrations of ferrocyanide.
Interestingly, when it was created in 1957 by engineers Alfred Fielding and Marc Chavannes, the original plan was to cover walls with a 3-dimensional textured pattern:
Only three years later it was discovered to be a superb packing material. Bubble wrap itself is made of low-density polyethylene (LDPE), a polymer of ethylene monomers that has some branching.
Branching around polyethylene reduces strands of it to pack closely, and this decreases its density.
Images from http://faculty.uscupstate.edu/llever/Polymer%20Resources/Topology.htm by David Whisnant
More recently, other amazing uses for bubble wrap have emerged. One example is from Bradley Hart, an artist in New York who injects different colors of paint into the bubbles to create portraits and landscapes:
Is there a place for bubble wrap in a chemistry lab? Most definitely! Professor George Whitesides and colleagues from Harvard University came up with some clever applications. Because the material is so cheap (about 60 cents per square meter) and the same area can have up to 5000 bubbles, the team discovered that the bubbles can safely hold liquid samples. This lead to a number of experiments testing the reliability of these plastic bubble holders:
Bubbles of Allura Red and rhodamine B dye - a test to see if liquid reagents can be stored and tested for absorbance measurements.
Image from dx.doi.org/10.1021/ac501206m; Anal. Chem. 2014, 86, 7478-7485.
Samples of E. coli grown in yeast and tryptone medium. Bubbles can be used to grow colonies of bacteria and microorganisms.
Image from dx.doi.org/10.1021/ac501206m; Anal. Chem. 2014, 86, 7478-7485.
A bubble can act as an electrochemical cell! Here 2 carbon electrodes are used to measure the current from different concentrations of ferrocyanide.
According to Professor Whitesides, bubble wrap can be repurposed to carry out a few chemistry and biology experiments in labs that normally cannot afford conventional test tubes and petri dishes.
Can you think of other unusual applications for bubble wrap? Test it out!
For further reading:
Adaptive Use of Bubble Wrap for Storing Liquid Samples and Performing Analytical Assays; David K. Bwambok, Dionysios C. Christodouleas, Stephen A. Morin, Heiko Lange, Scott T. Phillips, and George M. Whitesides; dx.doi.ord/10.1021/ac501206m; Anal. Chem. 2014, 86, 7478-7485.
Saturday, February 21, 2015
The Power of Transesterification - Making Biodiesel and Turning an Organic Network into Glass
You may not have heard of transesterification but probably heard about the compound this reaction produces: biodiesel. As a general reaction, it involves taking an ester and an alcohol and changing them into a different ester and alcohol.
You can think of this as transforming one ester into another. In the synthesis of biodiesel, transesterification typically starts with a fat which is a triester molecule. After reacting with methanol and a catalyst, a high yield of methyl esters or biodiesel can be collected.
You can think of this as transforming one ester into another. In the synthesis of biodiesel, transesterification typically starts with a fat which is a triester molecule. After reacting with methanol and a catalyst, a high yield of methyl esters or biodiesel can be collected.
Image from Dogpatch Biofuels
A few years ago this reaction was discovered to be highly useful in taking an organic polymeric network and turning it into a resin that has the hardness of glass, the ability to be reshaped, and is recyclable. Researchers Damien Montarnal, Mathieu Capelot, François Tournilhac, and Ludwik Leibler from Laboratoire Matiere Molle et Chimie in Paris, France modified bisphenol A diglycidyl ether with some di- and tricarboxylic acids to create an organic polymeric network with ester and alcohol functional groups.
Credit: Cyril Fresillon/CNRS
The stoichiometry and reversibility of this reaction allow the number of ester and alcohol groups to remain the same. The flexibility in changing how cross-links are formed enables this material to adopt various complex shapes.
For further reading, check out:
*Silica-Like Malleable Materials from Permanent Organic Networks by Damien Montarnal, Mathieu Capelot, François Tournilhac, and Ludwik Leibler; Science 18 November 2011: Vol. 334 no. 6058 pp. 965-968; DOI: 10.1126/science.1212648
Wednesday, February 18, 2015
Chemistry in a Work of Art - Light Spectra by Bev Precious
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| Light Spectra by Bev Precious, an aluminum and dichroic glass sculpture in the foyer of the chemistry building at UW-Madison (photo by Jeff Miller) |
The creation of dichroic glass involves a process called electron beam physical vapor deposition, where 10,000 V of electricity are concentrated in an electron beam and vaporizes a mixture of quartz and metal oxides of titanium, chromium, aluminum, zirconium, or magnesium. This mixture vapor is eventually deposited onto a glass surface and can be applied a layer at a time. Layer thicknesses are precisely controlled to allow multiple colors to be produced on the same glass.
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Image from Center for Nanoscale Science and Engineering
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Geodesic pattern glass from CBS
Dichroic glass has the special property of transmitting light of one color and reflecting light in a different color. Hence as you walk around a dichroic sculpture, you would see different colors evolve at different angles of observation.
Friday, February 13, 2015
How to Get More Out of Wood Waste - Breaking Down Lignin to Get Useful Aromatic Compounds
Lignin makes up almost a third of our planet's organic carbon and is a large waste component in paper processing. Research efforts have been focused on breaking this difficult material down and use its components for other useful purposes. The research team of Alireza Rahimi, Arne Ulbrich, Joshua J. Coon, and Shannon Stahl at UW-Madison have figured out a way to break down lignin.
How does this relate to what we’ve
learned in general chemistry?
Lignin
makes up almost a third of our planet’s organic carbon and is a large waste
component in paper processing. Research efforts have been focused on breaking
this difficult material down and use its components for other useful purposes.
The research team of Alireza Rahimi,
Arne Ulbrich,
Joshua J. Coon & Shannon S. Stahl at UW-Madison have figured out a way to
break down lignin. One of the first steps is the chemical oxidation of a secondary
alcohol group into a ketone, which is a key step in being able to break it down into smaller and potentially useful aromatic molecules.
Lignin (from popular or aspen)
Article:
Formic-acid-induced depolymerization of oxidized lignin to aromatics; Alireza
Rahimi,
Arne Ulbrich,
Joshua J. Coon & Shannon S. Stahl (researchers at UW-Madison Depts. Of
Chemistry and Biochemistry); Nature 515, 249–252 (13 November
2014) doi:10.1038/nature13867
Monday, February 9, 2015
Amino Acid in Watermelon Juice Relieves Muscle Soreness : L-Citrulline
Most amino acids have a chiral center with carboxylic acid and amine functional groups.
Researchers M. P. Tarazona-Diaz, F. Alacid, M. Carrasco, I. Martinez, and E. Aguayo tested the efficacy of L-citrulline on muscle soreness vs. a placebo. For a small group of young male volunteers in an ergometer exercise test, there was determined to be no significant difference in blood lactate concentration during the activity. But after 24 hours, recovery from delayed onset muscle soreness improved subsequent to ingesting 500. mL of natural and enriched watermelon juice.
Watermelon contains an amino acid known as L-citrulline which is also known to be an intermediate in the urea cycle, a biochemical pathway in the liver that enables the body to convert ammonia waste into urea which eventually is eliminated via the kidneys.
L-citrulline
The name comes from citrullus, meaning "watermelon". (http://en.wikipedia.org/wiki/Citrulline)
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