You are currently browsing the daily archive for June 17th, 2009.
Global Warming Impacts in Every Corner of the United States
“This report is a game-changer,” said Administrator Jane Lubchenco of the National Oceanic and Atmospheric Administration. “Much of the foot-dragging in addressing climate change is in the perception that climate change is a ways down the road and only occurring in remote parts of the planet.
“Climate change is happening now. It’s happening in our own backyards, and … it affects you and the things you care about.”
New Glimpse of Life’s Puzzling Origins
The origins of life on Earth bristle with puzzle and paradox. Which came first, the proteins of living cells or the genetic information that makes them? How could the metabolism of living things get started without an enclosing membrane to keep all the necessary chemicals together? But if life started inside a cell membrane, how did the necessary nutrients get in?
From Time to Oprah to Iran: Twitter Comes of Age
Twitter’s real-time messages of 140 characters or less have attracted attention before — most notably with eye-witness accounts during the November attacks on Mumbai — but nothing like the focus of the past days and weeks.
How I Learned to Stop Worrying and Encourage Internet Surfing in Class
I did have a secret weapon in the classroom. There was a switch that could turn all the monitors off, so they couldn’t surf if I wanted to lecture. So when I went into class on the first day, I was prepared to use The Switch whenever I needed the students’ attention. But at the end of the term, I had only used The Switch during days when other students were giving formal presentations (and I wanted the presenters to have a polite audience). When I was teaching, I just left their monitors working the entire time. And it was fine.
Dylan is getting closer (we hope) to figuring out some of the conditions necessary for SERS of lysozyme and bovine serum albumin (BSA). On Monday we figured out that a lot of what we were seeing in our spectra were bands from the phosphate buffer [1]. That’s what happens when you do control experiments! Since then, we decided to stop using the buffer and use DI water as our solvent.
Now Dylan has several (ok, lots) of spectra with broad bands that match up with the solid state lysozyme Raman spectrum we have (which matches up exactly with all the published spectra except one!). We aren’t sure why the bands are as broad as they are. One hypothesis is that our colloids have broad size distribution and we are observing a bulk average of many different SERS active sites. We plan to make more colloids and aim for a narrower extinction spectrum, which would indicate a more monodisperse colloid. Failing that, we may try core-shell nanoparticles, starting with an Au seed.
Dylan has also tried making Ag colloids using borohydride as the reducing agent [2]. The initial results looked good, but after storing them they aggregated. With colloids, cleanliness is very important.
[1] I think this is also in some published spectra too, not necessarily assigned correctly. More on that later.
[2] This is one of the several “Lee and Meisel” preps. Moral – if a paper says “Lee and Meisel method”, it could be one of up to four different preps for silver colloids. Reviewers need to tell authors to be more specific.
I’ve updated the Group page to include everyone I’ve worked with over the summer since I started at Coastal Carolina University in 1996. If we worked together and your name isn’t there, let me know and I’ll add you!
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