In lecture this week we discussed ferromagnets, and did not distinguish them from ferrimagnets or anti-ferromagnets. Using your favorite web search tool, do some research on this topic and let us know which of the following statements about these terms are accurate. Choose the single best answer.

If a portion of tissue has a faster T1 relaxation time scan than its neigbors, how will it typically appear in the MRI image?

In lecture this week, the concept of an external magnetic field was introduced. We did not distinguish between B (sometimes called the induction) and H (the magnetic field strength) because of time limitations in the class, but they are indeed different things. Do some web research on these two quantities, and select which statement below best captures the relationship between these two quantitites.

What are the challenges with moving to smaller bit sizes in magnetic data storage? Choose the single best answer.

For the purposes of MRI T1 contrast agents, what is the ideal shape of a nanoparticle? HINT: Consider the surface.

In Small Talk this week, we met Gary Stinnet who is a graduate student at the Baylor College of Medicine across the street from Rice. What is an example of a biological process he would like to study using cellular imaging made possible through nanoparticle contrast agents?

What can happen to a superparamagnetic nanoparticle as you cool it down? Choose the single best answer.

On slide 13 of this week's lectures, we show an energy barrier to spins flipping; later we discuss this concept as it pertains to nanoparticles. What is this barrier to spin alignment (through either rotation or grain boundary movement) proportional to? Choose the single best answer.

Does a superparamagnet have a remanent magnetization?

In lecture 5, we discussed the adsorption of arsenic (e.g. specifically arsenic oxoanions) onto iron oxide nanoparticles. The number 12 w/w% of arsenic on 12 nm diameter iron oxide nanoparticles was given. What would be the saturation adsorption if the particle sizes dropped to 6 nm diameter? Treat this approximately** You should not have to calculate anything. If you really want to calculate it directly, then use a 5 gm/cm^3 for iron oxide, then apply an arsenic oxide thickness of 4.5 angstroms, assume the density and stoichometry of that layer is like arsenic trioxide - 3.74 gm/cm^3.