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2006

Three-dimensional microfabrication for photonics and biomedical applications, at Macro 2006 - World Polymer Congress (Rio de Janeiro, RJ, Brazil), Sunday, July 16, 2006:
talk_1278.pdf
We use two-photon absorption polymerization to fabricate microstructures containing compounds with interesting properties for optical and biomedical applications. Our investigations open the door to new applications in data storage, waveguides manufacturing, organic LEDs, optical circuitry and scaffold for bio-applications.
Complex microstructures fabricated via two-photon absorption polymerization, at Macro 2006 - 41st Inernational Symposium on Macromolecules (Rio de Janeiro, RG, Brazil), Sunday, July 16, 2006:
talk_1334.pdf
Using acrylic resin and Lucirin TPO-L as photoinitiator, we fabricated complex microstructures via the process of two photon absorption (2PA) polymerization. We measured the 2PA cross-section of Lucirin TPO-L, which is the parameter responsible for the nonlinear process, and the value found is among the ones reported in the literature for common photoinitiators. We also carried out quantum chemistry calculation in order to correlate the nonlinear optical properties of this photoinitiator to its molecular structure.
The scientific approach to teaching: Research as a basis for course design, at 2006 Cottrell Scholars Meeting (Tucson, AZ), Saturday, July 8, 2006:
talk_1211.pdf
Discussions of teaching -- even some publications -- abound with anecdotal evidence. Our intuition often supplants a systematic, scientific approach to finding out what works and what doesn't work. Yet, research is increasingly demonstrating that our gut feelings about teaching are often wrong. In this talk I will discuss some research my group has done on gender issues in science courses and on the effectiveness of classroom demonstrations.
Visualizations and visual illusions: how the mind tricks us, at 2006 Cottrell Scholars Meeting (Tucson, AZ), Friday, July 7, 2006:
talk_1156.pdf
Neurobiology and cognitive psychology have made great progress in understanding how the mind processes information – in particular visual information. The knowledge we can gain from these fields has important implications for the presentation of visual information and student learning.
Interactive Teaching: Turning a Large Lecture into a Seminar, at Symposium on Technology in Undergraduate Education, Harvard University (Cambridge, MA 02138), Friday, June 16, 2006:
talk_1210.pdf
Education is more than just transfer of information, yet that is mostly what happens in large introductory courses -- instructors present material and students take down as many notes as they can. This format tends to reinforce the idea that learning is about acquiring information rather than gaining new ways of thinking. In undergraduate science, however, learning consists primarily of developing new thinking skills; this mismatch between instruction and learning leads to students misunderstanding what science is, as well as frustration for both students and instructors. The problem has a... Read more about Interactive Teaching: Turning a Large Lecture into a Seminar
Femtosecond laser micro and nano engineering for photonics and biology, at 4th International Congress on Laser Advanced Materials Processing (LAMP 2006) (Kyoto, Japan), Tuesday, May 16, 2006:
talk_1190.pdf
The interaction between intense laser pulses and transparent materials is an important research area, both for its intrinsic scientific value and for the technological applications that it feeds. Intense femtosecond pulses enable highly localized material modification in virtually any material, and thus femtosecond lasers are excellent tools for fabricating optical microstructures. Because of the nonlinear interaction between the femtosecond laser pulse and the medium, the interaction is confined to the focal volume, allowing precise machining in three dimensions in the bulk of the sample. In... Read more about Femtosecond laser micro and nano engineering for photonics and biology
Confessions of a converted lecturer, at Science Division Pedagogy Workshop, Hamline University (St. Paul, MN), Friday, May 5, 2006:
talk_1206.pdf
I thought I was a good teacher until I discovered my students were just memorizing information rather than learning to understand the material. Who was to blame? The students? The material? I will explain how I came to the agonizing conclusion that the culprit was neither of these. It was my teaching that caused students to fail! I will show how I have adjusted my approach to teaching and how it has improved my students' performance significantly.
Subcellular surgery and nanoneurosurgery, at Science Division Dinner, Hamline University (St. Paul, MN), Friday, May 5, 2006:
talk_1208.pdf
We use femtosecond laser pulses to manipulate sub-cellular structures inside live and fixed cells. Using only a few nanojoules of laser pulse energy, we are able to selectively disrupt individual mitochondria in live bovine capillary epithelial cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We have also used the technique to micromanipulate the neural network of C. Elegans, a small nematode. Our laser scalpel can snip individual axons without causing any damage to surrounding tissue, allowing us to study the function of individual... Read more about Subcellular surgery and nanoneurosurgery
Wrapping light around a hair, at Optics Physics Class (St. Paul), Friday, May 5, 2006:
talk_1207.pdf
Can light be guided by a fiber whose diameter is much smaller than the wavelength of the light? Can we mold the flow of light on the micrometer scale so it wraps, say, around a hair? Until recently the answer to these questions was ‘no’. We developed a technique for drawing long, free-standing silica wires with diameters down to 50 nm that have a surface smoothness at the atomic level and a high uniformity of diameter. Light can be launched into these silica nanowires by optical evanescent coupling and the wires allow low-loss single-mode operation. They can be bent sharply, making it... Read more about Wrapping light around a hair
Stopping Time, at Kay Malmstrom Lecture in Physics, Hamline University (St. Paul, MN), Friday, May 5, 2006:
talk_1140.pdf
Time is of philosophical interest as well as the subject of mathematical and scientific research. Even though it is a concept familiar to most, the passage of time remains one of the greatest enigmas of the universe. The philosopher Augustine once said: "What then is time? If no one asks me, I know what it is. If I wish to explain it to him who asks me, I do not know." The concept time indeed cannot be explained in simple terms. Emotions, life, and death - all are related to our interpretation of the irreversible flow of time. After a discussion of the concept of time, we will review... Read more about Stopping Time

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