Bored? Try Pharyngula or Doonesbury. Including my favourite Doonesbury ever... or FREE SF ebooks from Baen Books. Or you might like to play with fractal edges in the Mandelbrot set.

I can't and won't write about everything. Here are some links to good things by other people.

is a brilliant starting place for almost anything.... Use it! A reference source that you know to be sometimes wrong will help you to develop your research skills.

In an attempt to make myself entirely redundant, I have recorded some of my plenaries.

I'm still playing around with formats but I'm going to try and make both a full rerun of the powerpoint with voiceover as well as sound-only podcast.

Preliminary feedback on these things has been positive. Please let me know if you find them useful and if so, do you prefer the podcast or the powerpoint?

There are a few glitches on some of the powerpoints where the conversion software can't handle my animations. I've figured out workrounds for most of them and I will fix them when I get time...

This lecture deals with the things that saliva is good for. In short, buffering (and the importance of flow rate), lubrication, antibacterial activity and a teeny-tiny bit of digestion. The causes and effects of xersotomia are also considered.

An indroduction to neurophysiology for dental students.

A resource for dental student elective projects.

This presentation is a so far unique because you can actually see me lecturing. I really should try harder to stand still.

Talking Head Podcasts Too weird?

To save for iPod, right-click and "save target as". To listen, click the play button. To be weird, click all the play buttons.

Space for more....

Calculate free calcium concentration from total calcium, buffer concentration and the concentrations of other ions. An extreme resurrection. The algorhythms that underlie this software were created to run on a calculator way back in 1979.

Look at the fractal border of the Mandelbrot set using javascript and HTML.

Enter any three from weight, volume, formula weight and concentration and the software will calculate the fourth

Calculate Student's 't' value and the probability that two means are significantly different

Works only with MSIE. I will update this one soon.

Play with the Nernst and Goldman equations. Works only with MSIE because it needs VML. Unlikely to be updated. To see what this software can really do ... click model and then select action potential from the preset menu.

Pretend you have a patch clamp amplifier, a cell membrane and channel blocking drugs..... Works only with MSIE because it needs VML to plot graphs. Unlikely to be updated. Also available as a truly ancient download

Sums is a An arithmetic and times table tester, aimed at the 6-10 age group. It has lots of silly graphics to (try to) make the arithmetic less boring. The zip file contains everything you need. Extract it to any folder and then double click setup.exe.

Probe is a precision teaching tool. If you've never heard of precision teaching then you probably don't need the program. Designed for dyslexic children. The zip file contains everything you need. Extract it to any folder and then double click setup.exe.

FirstWordz is a point and click word processor. The top half of the screen is a very simple word processor. The lower half has a load of pictures. Click on a picture and the appropriate word gets added to your text. You can customise FirstWordz by adding your own pictures and creating your own lists of words. This program was designed with dyslexic children and beginning readers/writers of any age. The zip file contains everything you need. Extract it to any folder and then double click setup.exe.

All the usual disclaimers apply. If you can contrive a way of damaging yourself or your PC with my software then it is your fault and your responsibility. I would however have an academic interest in hearing how you managed it!

The nernst and goldman equations are mathematical descriptions of the membrane potential. So what? Well, membrane potential is critically important to the wellbeing of cells (and ultimately therefore of yourself). The membrane potential is an important driving force for secondary active transport in all cells and it underlies the action potential, which is what makes nerves and muscles work. It is impossible to genuinely understand any of these processes without knowing about the Nernst and Goldman equations.

The Nernst equation may be used to calculate the electrical potential (Pd) across a membrane when this membrane is permeable to a single ion.

Where: R = Universal gas constant (8.31441 J/mol/K); T = Absolute temperature (K); Z = valence; F = Faraday constant (96484.56 C/mol); ln = natural log; i = intracellular; o = extracellular

At body temperature, the Nernst equation may be simplified for a monovalent ion thus:

Where: log = log to base 10

The Goldman software will run the Nernst equation for potassium (K+). It is conceptually much easier to set ion levels and immediately see the effects on Pd than it is to stare at equations. In most animal cells, the dominant membrane conductance is to K+ so the Nernst equation for K+ is a sensible approximation of the membrane potential.

Truth be told, the Nernst equation does not give a very good estimate of membrane potential (it has other uses) becuse cells are permeable other ions. In many cells, in addition to the K⁺ conductance, the Na⁺ and Cl^- conductances are also important. The Goldman equation calculates membrane potential using the relative permeability (Pion) and the concentration gradient of all three ions.

Where: R = Universal gas constant (8.31441 J/mol/K; T = Absolute temperature (K); F = Faraday constant (96484.56 C/mol); ln = natural log; i = intracellular; o = extracellular

At body temperature, the Goldman equation may be simplified thus:

Where: log = log to base 10

If you find the Nernst Equation hard to swallow then the Goldman Equation is impossible. The Goldman software also runs the Goldman Equation and allows you to see first hand the effects of changing ion concentrations and even more importantly the effect of changing relative permeability on membrane potential.

The Goldman software also has some modelling capabilities. Choose any constant on the equation and then pick a time for it to change.... and how you want it to change.... run the software and see what happens. I have modelled the action potential as a demo.

Go ahead.... play

This is a bit of a weird one. The original version of the software was writen under DOS to accompany a series of Physiology Honours BSc. tutorials about membrane potential and voltage-clamps. A voltage clamp is an amplifier with appropriate feedback circuits that will hold any given potential across a membrane or other resistor. A patch-clamp amplifier is a voltage-clamp. If you voltage clamp a cell membrane to any potential other than its natural membrane potential then current will flow. The current will be carried by ions. Which ions will depend on the relative permability of the membrane to the ions and also on their concentration inside and outside the cell. If this sounds to you like a cross between the Goldman Equation and Ohms law then go to the top of the class. The Voltage Clamp software uses the Goldman Equation and Ohms law to figure out how much current will flow and what ion species will carry it. When you do real patch-clamp experiments all you can measure is total current... but you can set intra- and extra- cellular ion concentrations.... and you can use channel blockers (set permeability to 0). It is therefore usually possible to figure out what is carrying the current that you are measuring... The Voltage Clamp software can also be used to make testable predictions for patch-clamp experiments.

The original DOS version of the software has long since been retired... to be replaced by a version written for Windows 3.0 in 1992. This version is available for download because, incredibly, it works under Windows XP. The webware version is a lot easier to use.