Carmichael, Stephen W.

nema

Abstract This is not an article about the song made famous by the late (great) Don Ho. This is about a breakthrough in the understanding of how micrometer-sized bubbles can be stabilized for long periods of time. This can influence the taste, smell, and consistency of consumer products including food and cosmetics. In two-phase systems, which can include air (as bubbles) suspended within a liquid, the structures of the dispersed (bubbles) and continuous (liquid) phases play a critical role in determining the properties of the material. There is also the function of time in that the microstructure of the dispersed phase continuously evolves toward a state of lower energy by minimizing the surface area between the two phases (referred to as the interfacial area). In the long term, this time evolution diminishes the usefulness of two-phase systems. Emilie Dressaire, Rodney Bee, David Bell, Alex Lips, and Howard Stone have devised a way to stabilize a two-phase system for time periods of a year or longer.

Abstract Light microscopy has many advantages and several disadvantages. One of the advantages is that different wavelengths are perceived as different colors, and with the proper use of dyes, filters, etc. several different structures can be imaged in the same object. One the major disadvantages is that the resolution is limited by the wavelength, a limit known as the diffraction barrier. Several recently-developed techniques have allowed light microscopy to “break” the diffraction barrier, a phenomenon known as “super-resolution.” Lothar Schermelleh, Peter Carlton, Sebastian Haase, Lin Shao, Lukman Winoto, Peter Kner, Brian Burke, Cristina Cardoso, David Agard, Mats Gustafsson, Heinhrich Leonardt, and John Sedat have created a new microscope that not only achieves super-resolution, but creates images in 3 dimensions and multiple colors. Not only that, but preparing specimens to examine with this microscope uses conventional methods, and they claim the microscope is easy to use!

Abstract Embryologic development is a dynamic process that has been previously studied by examining static (usually chemically-fixed) specimens at different time periods and then extrapolating results by assembling a series of static images. Recently, Amy McMahon, Willy Supatto, Scott Fraser, and Angelike Stathopoulos have developed new methods to look at developmental migration patterns in real time. They used an optimized imaging approach and quantitative methods to analyze a two hour period during which gastrulation occurred in the embryos of fruitflies (Drosophila). Specifically, they characterized the complex interactions between cells of the ectoderm and mesoderm by tracking the movements of over 1,500 cells, which involved the analysis of over 100,000 cell positions for each embryo!

Abstract It is relatively infrequent these days for a novel mineral to be discovered in the natural environment (in this context, this implies on the Earth). On the rare events of such a discovery, the new mineral is typically found in milligram quantities. In an article by Ronald Peterson, William Nelson, Bruce Madu, and Herbert Shervell, they describe the discovery of kilograms of a mineral that had only been synthesized previously, but never before detected in the natural environment. As if that were not impressive enough, they went looking for this mineral because they thought it had been observed on Mars!

Abstract It has been appreciated that many invertebrates have morphologic and/or behavioral traits that help them survive by camouflage for predator avoidance or being stealthy predators themselves. The morphologic features that are involved have been described in greater detail as the technology has evolved. Recently, Rebecca Duncan, Kellar Autumn, and Greta Binford have used dissecting microscopes and scanning electron microscopes (SEM) to reveal new details of how certain species of spiders hide themselves by covering themselves with sand, and how the sand particles tenaciously stick to the spiders’ bodies.

Abstract Fluorescence microscopy has revolutionized cell biology. Not only has it increased the spatial resolution with which certain processes are visualized, but it has allowed microscopists to monitor more than one event at a time. One of the remaining challenges is to see how proteins fold and assume their native conformations within living cells. Recently, Nathan Luedtke, Rachel Dexter, Daniel Fried, and Alanna Schepartz have demonstrated a technique to demonstrate these events in situ.

Abstract It was demonstrated 18 years ago that atoms could be manipulated, one at a time, on a surface. Yet only recently has the force required to move an atom been determined. Markus Ternes, Christopher Lutz, Cyrus Hirjibehedin, Franz Giessibl, and Andreas Heinrich, in a technical tour de force, have engineered a microscope that incorporates features of the scanning tunneling microscope (STM) and atomic force microscope (AFM) to accurately quantitate the lateral and vertical forces needed to move a single atom on a surface.

Abstract For the first few centuries of microscopy, spatial resolution was limited by the diffraction barrier. Recently, this barrier has been broken using several different methods. Optical methods that provide better resolution than the diffraction barrier are referred to as super-resolution. Although these techniques have significantly improved resolution in two dimensions (x and y) or in the axial dimension (z), it has not been possible to achieve substantial improvement in all three dimensions simultaneously. A study by Bo Huang, Wenqin Wang, Mark Bates, and Xiaowei Zhuang demonstrated a breakthrough by achieving a spatial resolution that is 10 times better than the diffraction limit in all three dimensions without using sample or optical-beam scanning.

Abstract There are several “molecular machines” that have been devised on a nanometer scale, made from proteins, DNA, and other molecules. A molecular machine is a system that generates physical forces at the atomic level, controlled by an external stimulus. Since all of the proposed circuits connect components linearly, they only communicate with one machine at a time. Now, Anirban Bandyopadhyay and Somobrata Acharya have devised an ingenious device that has the potential to communicate different instructions to many molecular machines simultaneously. They demonstrated that 2,3,5,6-tetramethyl-1–4-benzoquinone (duroquinone; DRQ) can be assembled as 17 identical molecules, one central molecule surrounded radially by 16 others. The central molecule can control the conformation of all the others when switched to one of four logic states by suitable pulses from an atomic sharp needle of a scanning tunneling microscope (STM).