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| Sunday, 6 February 2005 |
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Junior Observer |  |
| News Business Features Editorial
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How sound helps to get images inside the body
The technique is similar to the echolocation (method used to communicate) by bats, whales and dolphins, as well as SONAR used by submarines. The ultrasound machine transmits high-frequency sound pulses into your body using a probe. The sound waves travel into your body and hit a boundary between tissues (e.g. between fluid and soft tissue, soft tissue and bone). Some of the sound waves are reflected back to the probe, while some travel on further, until they reach another boundary and are reflected. The reflected waves are picked up by the probe and relayed to the machine. The machine calculates the distance from the probe to the tissue or organ (boundaries), using the speed of sound in tissue and the time of each echo's return. The machine displays the distances and intensities of the echoes on the screen, forming a two dimensional image.In a typical ultrasound, millions of pulses and echoes are sent and received each second. The probe can be moved along the surface of the body and angled to obtain various views. Different types Ultrasound presents a two dimensional image or "slice" of a three dimensional object. Two types of ultrasound are currently in use, 3D ultrasound imaging and Doppler ultrasound. Major uses Ultrasound has been used in a variety of clinical settings.The main advantage of ultrasound is that certain structures can be observed without using radiation. Ultrasound can also be done much faster than X-rays or other radiographic techniques. Here are some uses for ultrasound: * Cardiology * Examining the inside of the heart to identify abnormal structures or functions * Measuring blood flow through the heart and major blood vessels * Dectecting kidney stones There is also a growing use for ultrasound as a rapid imaging tool for diagnosis in emergency rooms. Dangers There have been many concerns about the safety of ultrasound. This is mainly because ultrasound is energy. However, no proven ill-effects of ultrasound have been documented in studies in either human beings or animals. This said, it should still be used only when absolutely necessary (it is always better to be cautious). The future As with other computer technology, ultrasound machines will most likely get faster and have more memory for storing data. Transducer probes will probably get smaller, and more insertable probes will be developed to get better images of internal organs. Very likely, 3D ultrasound will be more developed and become more popular. The entire ultrasound machine will probably get smaller, perhaps even hand-held for use in the field (e.g. by paramedics or those working in battlefields). One exciting new area of research is the development of ultrasound imaging combined with heads-up/virtual reality-type displays that will allow a doctor to "see" inside you as he/she is performing a minimally invasive or non-invasive procedure. *********** The ultrasound machine A basic ultrasound machine has the following parts: * Transducer probe - probe that sends and receives the sound waves * Central Processing Unit (CPU) - a computer that does all the calculations and contains the electrical power supplies for itself and the transducer probe * Transducer pulse controls - changes the amplitude (breadth), frequency and duration of the pulses emitted from the transducer probe * Display - displays the image from the ultrasound data processed by the CPU * Keyboard/cursor - inputs data and takes measurements from the display * Disk storage device (hard, floppy, CD) - stores the acquired images * Printer - prints the image from the displayed data *********** How the Venus flytrap lures its victims
The plant (Latin name Dionaea muscipula), one of the marvels of nature, has been described by Charles Darwin as "one of the most wonderful in the world". It is able to enclose a fly within its clamshell-shaped leaves in just 100 milliseconds, faster than the blink of an eye. Previous work done by scientists established that the flytrap lures the insect with a smell exuded from the leaves' inner surface. When the fly walks on the surface, it activates a hair trigger and causes closure of the leaf. How exactly this closure is effected baffled scientists for years, as it does not have the nerves and muscles of fast-moving animals. Now, according to a study published in the weekly British science journal, Nature, American and French scientists believe they have explained how the Venus flytrap snaps shut to snare its victims. The answer lies in tensile strength. The plant first bends back its rubbery leaves so that they are convex-shaped, like half a tennis ball that has been flipped inside-out. To close the trap, it releases the tensed-up energy. The leaves instantly flip from convex to concave - as if the half tennis ball has suddenly popped back to its normal shape. Their edges snap together with the insect trapped inside. According to the authors of the study, the closure of the leaves is characterised by the slow storage and release of elastic energy. The researchers were able to model the change in geometry by putting microscopic dots of ultraviolet fluorescent paint on the external surface of the leaves. They then filmed the closure under ultraviolet light, using a high-speed video at 400 frames per second, which showed the leaves' sudden shift from convex to concave when the trap closed. However, the study still has not discovered the phase in between - exactly how the signal is transmitted from the hair trigger to the closure mechanism at such a speed. Source: AFP |
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| Politics | Produced by Lake House |
You might have heard the word ultrasound especially with regard to
medical tests. But do you know what it means? Ultrasound or
ultrasonography is a medical imaging technique that uses high frequency
sound waves and their echoes, to get images inside the body.
The Venus flytrap is not a plant that one would come across regularly.
You may be surprised to hear that it is carnivorous (meat eating). Indeed,
it does feed on small insects which may be unfortunate enough to land on
its leaves.
