Author Archives: Brock Tice

My New Home Network

In the last week or so I’ve finished setting up my home network. It includes

  • A Linksys WRT54GL
  • A Linksys NSLU2
  • A LaCie 500GB external disk
  • A Motorola SurfBoard cable modem

The WRT54GL is running a custom Linux firmware (DD-WRT), which allows me to tweak all kinds of settings (including radio power), log in with SSH, and if I solder an SD card onto the motherboard, load all sorts of additional software. The management software is much nicer than what it comes with.

The NSLU2 is also running a custom linux firmware (OpenSlug). It’s somewhat Debian-like. I added a 1GB memory stick to one of its USB ports, and hooked up the LaCie 500GB external disk to the other. The operating system resides on the 1GB memory stick, while I serve files, run backups, and serve iTunes music (with mt-daapd) from the 500GB drive. The iTunes music shows up as a shared library on the macs, available for streaming. The custom firmware also allows the use of a usb hub. Once I get one, I’m probably going to hook the printer up to it, and use it for print serving as well.

The cable modem doesn’t do much. It just hooks us up to the ‘net. Here’s a picture of the set-up. Notice the penguin in a slug suit on the NSLU2 (because the devices are referred to as slugs).

Home network

MIT Tech Review Article on Stem Cell Differentiation Control

Biosingularity links today to an article in the MIT Technology Review on the state of science with regard to directing differentiation of stem cells into more specific types and tissues. This is of course an area that has been under study for a while. It’s essential to our potential ability to engineer replacement tissues. At the heart of the issue is what makes cells — which each have the entire blueprint for your body — develop into particular types, at the level of DNA transcription.  While the pathways and molecules involved have been under investigation with some fruitful results, this is a major step in that people are beginning to integrate all of the information that’s been discovered, with an aim toward total deliberate control of cell development.

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Article Review: Role of ATP-Regulated Potassium Channels … [in] Ischemia by Furukawa et al.

Another long title. The whole thing is below.

Hubmed Page: Role of Cardiac ATP-Regulated Potassium Channels in Differential Responses of Endocardial and Epicardial Cells to Ischemia

This 8-page article quantifies in great detail the ATP sensitivity of ATP-regulated potassium channels, often referred to as IK(ATP). As the article shows by many references, it’s known that the epicardium of the heart is more sensitive to lack of oxygen (and therefore metabolic energy in the form of adenosine triphosophate — ATP) than then endocardium of the heart. The authors of this study first measured currents from ATP-regulated potassium channels in the presence of CN– (cyanide, which blocks the generation of ATP), and then more directly pulled off patches of cell membrane with ATP-regulated potassium channels, and tested them in the presence of varying concentrations of ATP. In both cases, action potentials (the way in which cardiac cells ‘fire’ to initiate contraction and signal each other) were shortened more in the epicardial patches than in those from the endocardium. The degree to which this shortening occurred and at what concentrations is well-documented in the article.
The results of this study are clear, well-presented, and extremely useful in modeling ischemia in the heart. It’s a long read, with a ton of experimental detail, but the results are worth slogging through all of that. This fundamental article on ATP-regulated potassium channels is a must-read for anyone wanting to study ischemia and infarction in the heart.