In this Issue

- Membrane Permeability
  Experiment
- ISE-100 pH Electrode
  Tech Note
- Web resources
- Year-End Equipment
  Discounts
- Updates to the iWorx
  User Area on the Web
- Clearance Items

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The iWorx newsletter is a FREE monthly publication dedicated to sharing teaching laboratory techniques and other useful information with educators in the fields of Anatomy and Physiology. We will also be sending you technical information and info on new developments at iWorx that we feel may be of use to you in your teaching and research activities.

About iWorx
iWorx has everything you need to add excitement and distance learning to any physiology teaching program. Our products include data acquisition hardware, professionally -developed physiology courseware, innovative web tools, and a full selection of transducers, cables, front ends and accessories.

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November 2006

 Experiment:  Membrane Permeability

A cell is the basic unit of life in which the biochemical reactions needed to maintain the life of the organism occur. The enzymes, substrates, and products of these reactions are contained within the cell by a structure known as the cell membrane. There are also organelles within the cell that are separated from the cytoplasm by membranes so that specific reactions can be concentrated within those organelles. The cell membrane is more than just a barrier that separates the contents of the cell from the surrounding environment. The cell membrane regulates the movement of molecules, which could be nutrients or waste products, into or out of a cell. Since some, but not all, particles are allowed to move across cell membranes, membranes are considered to be selectively permeable. The processes by which molecules move across membranes, and the rates at which they do it, are dependent on the type of molecule and its size, electrical charge, and concentration on either side of the membrane. Processes that consume energy are classified as active transport; processes that do no require energy are considered to be forms of passive transport.

In this experiment, students will examine some of the properties of passive transport across a model of a membrane created with dialysis tubing. Each sac created with dialysis tubing will be filled with one of three different solutions, each containing a different set of ions. When each dialysis sac is placed in a beaker of deionized water, ions will move across the membrane. The movement of ions between the dialysis sac and the surrounding water will be indicated by a change in the pH of the water surrounding the dialysis sac.

Download Membrane Permeability experiment.

Download screen optimized or press optimized Membrane Permeability experiment.

ISE-100 pH Electrode

The ISE-100 is an easy-to-use pH electrode that is capable of measuring the acidity of solutions over a pH range of 0 to 12.  The ISE-100 is a combination electrode with both the recording and reference electrodes included in the same housing.  The plastic housing at the end of the electrode protects the glass membrane and reduces the probability of the electrode breaking as it is handled. 

View a Tech Note here.

ISE-100 pH Electrode

ISE-100

pH Electrode

$155

$125

Download the updated settings group for this month’s experiment and the other experiments published in the iWorx Newsletter.

Whether you plan to download any of the experiments announced in recent editions of the iWorx Newsletter or a new copy of the LabScribe Installation CD, you need a password and an ID to access the download sites for these items. 

To register for a new ID and password, please go here.   After you receive confirmation that user account has been activated, return to the same site and click on the Enter link. 

Registered users can log-in here.

To download screen or press optimized copies of the latest lab experiments and Tech Notes published in the iWorx Newsletters, go here and select the lab experiment of interest.

If you plan to use any of the experiments or manuals announced in recent editions of the iWorx Newsletter, you should obtain a copy of the settings group used to configure LabScribe for these experiments.  To download the settings file, right click here and choose "Save Target As" in the Internet Explorer browser or "Save Link As" in the Firefox browser.  Save the file in your LabScribe Folder.  When you launch LabScribe, the settings group will be available from Load Group command in the Settings menu.

The write-ups and the settings files for the blood pressure experiments in the iWorx Physiology Manual have been updated.  The latest version of the LabScribe Installer CD that contains the updates, is available for free on the iWorx Users Area.

Learn more about membranes and membrane permeability by going to the external Web resources page.

On this page we have also accumulated a host of links to informative, external physiology Web sites and conveniently categorized them into major sub categories for easy reference.

  Year-End Special Offer on Select iWorx Equipment
  with Free Shipping

Whether you are planning new physiology lab curricula or replacing worn lab equipment, take advantage of iWorx end of the year equipment promotion with free shipping (North America only).  

Save 20% on a selection of the most widely used stimulators, electrodes, transducers, probes, accessories and Web teaching tools used in iWorx physiology teaching labs.  Go to www.iworx.com/specialoffers to see the full listing, descriptions, and prices of discounted equipment and order today.  Offer ends December 31, 2006.

Updated iWorx User Area on the Web

The iWorx user area on the Web has been updated with new downloads, tech notes, and products updates.  Be sure to visit to see what's new.

Clearance Items

iWorx has a large supply of new and trade-in items at up to 70% discount.  Also check with us about trade in allowances for your older Powerlab or Biopac equipment.  Customers in the U.S. and Canada can order directly online. See specials