Humans and animals need healthy organs to live. Due to medical conditions and accidents, some organs fail to function properly. For these reasons, the medical community has experimented and can now perform successful organ transplants, allowing patients to continue to live their lives. Many countries have medical programs where individuals can donate their organs and tissue (bones, tendons, skin, cornea, etc.) to assist those in need of transplants. These practices and medical miracles have become possible during the last decades. [ILLUSTRATION OMITTED] Almost anyone can sign up to become an organ donor, as no age limit exists. From newborns to senior citizens, the procurement of organs has helped to save many lives. People under the age of 18, however, must have permission from a parent or guardian (Who Can Donate, http://organdonor. gov/donation/who_donate.htm). To become a donor, all an individual has to do is complete a Uniform Donor Card similar to the one shown in Figure 1 (often available as part of a driver's license application) that permits medical teams to harvest organs or tissues when you are about to die or very shortly after death. Few medical exclusions exist, with the exception of HIV, active cancer, and systemic being the only absolute exclusions. Organs and tissues from individuals with other medical conditions will be evaluated by doctors to determine if they are suitable for donation. The key in organ donation is the condition of the organ, not the age. Even though it takes little effort to become an organ donor, many people spend years on the waiting list due to the shortage of organs. [FIGURE 1 OMITTED] Although physicians from earlier times attempted human limb transplants, successful transplants began with the eye cornea and were first reported in 1906 by Edward Zirm, MD (www.ulleb.org/history_of_corneal_transplan. htm). The major drawbacks to early transplants were organ rejections and infections. Research during the 1940s gave scientists a better understanding of the role the immune system played in organ donation. Their discoveries led to the development and use of the first immunosuppressive drugs in the hopes that by suppressing the normal immune reaction, the chances of organ rejection would decrease. However, the first drugs used also killed the patient's bone marrow cells, leaving patients, vulnerable to all kinds of infections (Grace, 296, p. 61). As a result, survival rates were very low. During the 1970s though, transplant success greatly improved as the discovery of the immunosuppressive drug, cyclosporine, solved this problem and transformed the world of organ donation. Produced by a fungus that actually lives in soil, cyclosporine works by only inactivating a person's T-cells, a type of white blood cell involved in the immune response, leaving the remainder of the immune system intact. Few side effects are associated with taking cyclosporine, and those that do occur go away when the patient stops taking the medication. Since the first use of cyclosporine in humans in 1978, survival rates for liver and kidney transplants have doubled, and rejection of heart transplants has been virtually eliminated (Grace, 2006). The increased survival rates due to the use of cyclosporine, however, brought about a new problem with organ donations--lack of organ supply. This Resources in Technology piece will explain organ and tissue transplants currently being performed throughout the medical community. What is Organ Harvesting? Organ harvesting is the taking of a healthy organ from a human body that is dying or clinically dead (Reference.MD, 2007, www.reference.md/files/D019/mD019737.html). Organs and tissue are usually harvested from people who volunteer as organ donors upon their death. The person must be breathing and their heart must be beating; however, they have been medically determined to be brain dead. Organs that can be donated by an individual who has died include the kidneys, liver, heart, lungs, pancreas, and intestines. …
Introduction In this challenge, students will have an opportunity to investigate the challenge of using a watershed area as a site for development, examining the many aspects of this multifaceted problem. [ILLUSTRATION OMITTED] The Watershed The watershed we are going to consider is approximately four square miles in surface area, serving the drinking water needs of approximately 75,000 citizens. The drinking water is obtained from several well fields scattered around the preserve, with well depths ranging from 110-300 feet. This water is then collected and sent to a pumping station that delivers it to an elevated storage facility that then feeds the town. Recently, the town fathers have decided to investigate the possibility of using selected portions of this reserve for development, perhaps in applications that can generate some badly needed revenue for the town and help offset the expenses required to maintain and operate the watershed. The main question, of course, is can this be done without compromising the quality and integrity of the drinking water? The Challenge Obviously, a search of both positive and negative experiences involving watershed development needs to be identified and assessed. What have communities, national and international, done to make productive and safe use of their watershed lands? What have been the major concerns they have raised, and/or solved? Is there long-term information available that documents the impacts or lack of impacts with the development efforts? How did they know which areas of the watershed would be most critical to development, or should be placed off limits ... and why? Perhaps you may want to create a scenario in the form of a paper plot plan of a mythical watershed where you can show the location of well fields, water-pumping station and associated facilities, access points via dirt roads, and other geographical features so the students have a visual tool around which to base their discussions and ideas. [ILLUSTRATION OMITTED] Stimulate discussion about the kinds of revenue-generating investments that could be considered for location in the watershed. From a list of these options, students can base some vs. or advantages vs. disadvantages types of discussions or evaluation matrices using a spreadsheet form of display--a technique engineers and land-use planners often use. Here are some items for your list of development options: * Golf course * Condominium housing * Solar and wind systems to generate electricity * Nature center with tour facilities * Conference center * Ornamental tree nursery * Firewood sale center [ILLUSTRATION OMITTED] As students consider the pros and cons of these and other potential uses they identify, it is important they not only consider the possible land-area impacts, but the related impacts these developments might present, such as: * The need to build roads or provide parking * Opening the watershed areas to human activities * Potential chemical spills onto the ground * Soil erosion * Water drainage or runoff changes * Disturbance to once pristine areas * Impact on wildlife and habitat changes * Controlling access to parts of the watershed * Policing or patrols required * Need to apply deicing compounds during winter * Application of fertilizers or pesticides * Illegal dumping of materials * Poaching of animals [ILLUSTRATION OMITTED] All of these are valid concerns for assessment and evaluation. …
Introduction One of the most significant technological issues of the 21st Century is finding a way to fulfill our energy demands without destroying the environment through global warming and climate change. Worldwide human population is on the rise, and with it, the demand for more energy in pursuit of a higher quality of life. In the meantime, as we use up our fossil fuel energy supplies, the quality of our environment is diminishing. By finding a way to provide clean, sustainable, environmentally friendly energy, we can reduce greenhouse gas emissions and help reverse the negative trends afflicting our planet (Sweet, 2006). One very promising technology that is currently being utilized and is continually being improved is the hydrogen fuel cell (HFC). It is an energy-conversion device that converts hydrogen fuel into usable electricity. HFC technology has the potential to help satisfy the rapidly growing energy demands of the world, and in turn, improve the quality of our environment. With this kind of potential, research and development in HFC technology continues to produce viable energy alternatives through the combined efforts of many scientists, engineers, and technologists (Borowitz, 1999). The aim of this article is to provide an overview of HFC technology, and with it, a description of its simplicity in design and functionality. In addition, a rationale for HFC content and several strategies for teaching about this exciting technology are presented. What is a Hydrogen Fuel Cell? An HFC is an electrochemical device that acts to convert chemical energy directly into electrical energy. The entire electrochemical conversion process is accomplished cleanly and efficiently without the use of any moving parts. During the process, a fuel of hydrogen-rich compounds is converted into electricity in the form of direct current that can be used much like a battery, as long as the fuel is supplied to the cell. A combination of fuel cells can be connected in series or parallel circuits in order to increase electrical voltage or current output. Stacking cells together in series or parallel creates what is termed a fuel-cell stack. A variety of fuel cell designs are being pursued and developed for a wide variety of applications. Many of these designs have already been implemented and continue to gain acceptance as effective means of providing electrical power. The multitude of HFC designs are classified by the type of electrolyte that they employ. Electrolyte types determine how the HFC functions, specifically, the temperature range at which they operate, the catalysts they utilize, the fuel they require, and other factors upon which they depend (USDOE, 2007; Hoogers, 2003). Of all currently utilized HFC designs, the Proton Exchange Membrane (PEM) fuel cell can serve as the focus of beginning HFC instruction, "because of [its] simplicity, viability, quick start-up, and ability to be utilized in almost any conceivable application, from powering a cell phone to a locomotive" (Sammes, 2006, p. 27). The PEM fuel cell functions through the use of a specially designed and produced polymer that acts to create a voltage difference with the addition of hydrogen fuel and oxygen (Basu, 2007; Hoogers, 2003; Sammes, 2006). A complete breakdown of the PEM fuel cell can be seen in Figure 1, illustrating the simplicity of its components in both design and functionality. [FIGURE 1 OMITTED] How do Hydrogen Fuel Cells Function? PEM fuel cells run on hydrogen and oxygen and produce only electricity, water, and excess heat as by-products of their operation. The production of electricity happens through an electrochemical process known in science as an oxidation-reduction (redox) reaction, which takes place at the anode and cathode of the fuel cell. In this type of reaction, what actually occurs are two simultaneous half reactions. At the anode of the fuel cell, hydrogen is being oxidized (losing electrons), and at the cathode, oxygen is being reduced (gaining electrons). …
