English for Bio-Medical Engineers (self-study competence development). Учебное пособие

Condenser Lens: The purpose of the condenser lens is to focus the light onto the specimen. Condenser lenses are most useful at the highest powers (400X and above). Microscopes with in stage condenser lenses render a sharper image than those with no lens (at 400X). If your microscope has a maximum power of 400X, you will get the maximum benefit by using a condenser lenses rated at 0.65 NA or greater. 0.65 NA condenser lenses may be mounted in the stage and work quite well. A big advantage to a stage mounted lens is that there is one less focusing item to deal with. If you go to 1000X then you should have a focusable condenser lens with an N.A. of 1.25 or greater. Most 1000X microscopes use 1.25 Abbe condenser lens systems. The Abbe condenser lens can be moved up and down. It is set very close to the slide at 1000X and moved further away at the lower powers.

Diaphragm or Iris: Many microscopes have a rotating disk under the stage. This diaphragm has different sized holes and is used to vary the intensity and size of the cone of light that is projected upward into the slide. There is no set rule regarding which setting to use for a particular power. Rather, the setting is a function of the transparency of the specimen, the degree of contrast you desire and the particular objective lens in use.

How to Focus Your Microscope: The proper way to focus a microscope is to start with the lowest power objective lens first and while looking from the side, crank the lens down as close to the specimen as possible without touching it. Now, look through the eyepiece lens and focus upward only until the image is sharp. If you can't get it in focus, repeat the process again. Once the image is sharp with the low power lens, you should be able to simply click in the next power lens and do minor adjustments with the focus knob. If your microscope has a fine focus adjustment, turning it a bit should be all that's necessary. Continue with subsequent objective lenses and fine focus each time.

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7.4 Text D. Surgical Microscopes in Ophthalmology

7.4.1 Memorize the following words and word-groups from the texts of the unit:

7.4.2 Read the following words and word-groups:

eye procedure, outpatient, corneal correction, vitreous humor, surgery, posterior segment, challenge, retina, clouding of the lens, high-intensity transmission optics, coaxial expandable, requirements.

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7.4.3 Read and translate the text using the dictionary. Be ready to speak on the topic.

Ophthalogy

Figure 9 – Surgical Ophthalmology – microsurgery on the eye

Surely, vision is the most important of a person's five senses. Accordingly, the variety of eye procedures extends from routine outpatient corneal correction to complex operations on the retina and vitreous humor.

Surgery on the posterior segment presents special challenges for the surgeon and the microscope. Because the retina is highly light-sensitive, only low level illumination is allowed. This means that the optics have to work very efficiently. TheLeica Low Light concept – with direct halogen illumination and high-intensity transmission optics – provides the necessary contrast ratio for retina procedures.

Efficient operation ensures the patient's comfort and well-being. Operations in the anterior segment are often done on an outpatient basis. To ensure the cataract patient's comfort, operating the microscope must be intuitive and reliable in every phase of surgery. Leica’s coaxial double beam stereo illumination and OttoFlex™ II finally provide a stable red reflex, even with difficult anatomical conditions (e.g. small pupils or advanced clouding of the lens).

Leica microscopes are modular and expandable. They meet the specific requirements of educational institutions and small clinics with limited space in their operating rooms.

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Figure 10 – Operations in the anterior segment of patient's eye

Figure 11 – a) Leica M844 F40 / F20Premium class in ophthalmic surgery; b) Leica M822 F40 / F20The Ultimate Red Reflex Surgical Microscope

Figure 12 – a) Leica M620 F20Easy-to-use, high-quality ophthalmic microscope; b) Leica DI C800Digital Imaging Color Module for Ophthalmology

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7.5 Text E. Operation microscope 10960 (1)

7.5.1 Memorize the following words and word-groups from the texts of the unit:

7.5.2 Read the following words and word-groups:

surgeons, fatigue, delicate operations, optional accessories, application, high efficiency, diagonal base, pentagonal, counterbalance mechanism, adjustable, horizontal arm, filament, finger, detachable, protection caps, hygiene, emergency, manipulate.

7.5.3 Read and translate the text using the dictionary. Be ready to speak on the topic.

Inami &Co.,LTD

No. 24-2 Hongo 3-chome

Bunkyo-ku,Tokyo 113, Japan

Tel.(03) 814-5916 FAX.(03) 814-3334

Telex.02723147 HINAMI I

CABLE ADDRESS.HONGOINAMI TOKYO

® TRADE MARK OF INAMI &Co.,LTD

Application The new INAMI Operation Microscope provides surgeons with a finely focused clear and sharp image, minimizing fatigue during delicate operations. Combined with a variety of optional accessories, it offers wide applications with high efficiency.

For added stability, the stand's 700mm diagonal base is pentagonally shaped with

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five caster legs, plus a counterbalance mechanism is incorporated at the end of the arm that sits at the top of the 1,400mm high vertical shaft. The latter allows for free up and down movement of the binocular arm which can be precisely positioned at the desired point with only a minimum of force. The horizontal arm is 400mm long with 3200 rotation, while the counterbalanced one is 560mm and rotates 2800.

Focusing is motorized for trouble free operation merely stepping on the foot pedal. Its range is total 40mm, or 20mm each for the UP and DOWN movements (at the speed of 2mm per second. Total magnifications are adjustable in five steps. Most control knobs to be manipulated with one's fingers have detachable protection caps to permit easy sterilization for enhanced hygiene.

Main illuminator employs two sets of bright and cool 15V 150W halogen lamps: one is used for actual illumination, and the other is a spare in case of emergency. Its lighting is guided to the optical head through a fiber optic cable. Should the filament of the lamp in use be blown during surgery, the illumination source can be immediately switched to the other lamp by pulling off the light guide and attaching it to the second lamp. Further, replacement of the burnt lamp after the surgical process is very simple.

Innovations A Rich Variety Of Optional Accessories Further Extends Functional Ability. Any kind of surgical situation can be satisfied by combining the necessary parts selected from a wide array of optional accessories. With appropriate adaptors, image recording and or monitoring on a TV screen through a still or video camera is also possible.

7.5.4 Speak on the main principles of surgical microscope operation using the information given in the texts of Unit 7.

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8 Unit 8. Laser Technology

8.1 Text A. Laser and its applications

8.1.1 Memorize the following words and word-groups from the texts of the unit:

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8.1.2 Read the following words and word-groups:

mysterious, sword of heat, amplification, emission of radiation, sophisticated, to vaporize, heat – resistant, thermonuclear reaction, Physicists, to disintegrate, vibrating, simultaneously, encyclopedia Britannica, satellites, subsequently.

8.1.3 Read and translate the text using the dictionary. Be ready to speak on the

topic.

In the ‘War of Worlds” written before the turn of the century H. Wells told a fantastic story of how Martians almost invaded our Earth. Their weapon was a mysterious “sword of heat”. Today Wells’ sword of heat has come to reality in the laser. The name stands for light amplification by stimulated emission of radiation.

Laser, one of the most sophisticated invention of man, produces an intensive beam of light of a very pure single colour. It represents the fulfillment of one of the mankind’s oldest dreams of technology to provide a light beam intensive enough to vaporize the hardest and most heat - resistant materials. It can indeed make lead run like water, or, when focused, it can vaporize any substance on earth. There is no material unamenable to laser treatment and by the end of 2000 laser will have become one of the main technological tools.

The applications of laser in industry and science are so many and so varied as to suggest magic. Scientists in many countries are working at a very interesting problem: combining the two big technological discoveries of the second half of the 20-th century - laser and thermonuclear reaction - to produce a practically limitless source of energy.

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Physicists of this country have developed large laser installations to conduct physical experiments in heating thermonuclear fuel with laser beams. There also exists an idea to use laser for solving the problem of controlled thermonuclear reaction. The laser beam must heat the fuel to the required temperature so quickly that the plasma does not have time to disintegrate.

According to current estimates, the duration of the pulse has to be approximately a thousand - millionth of the second. The light capacity of this pulse would be dozens of times greater that the capacity of all the world’s power plants. To meet such demands in practice scientists and engineers must work hard as it is clear that a lot of difficulties are to be encountered, on route.

The laser’s most important potential may be its use in communications, the intensity of a laser can be rapidly changed to encode very complex signals. In principle, one laser beam, vibrating a billion times faster than ordinary radio waves, could carry the radio, TV and telephone messages of the world simultaneously. In just a fraction of a second, for example, one laser beam could transmit the entire text of the encyclopedia Britannica.

Besides, there are projects to use lasers for long distance communication and for transmission of energy to space stations, to the surface of the Moon or to planets in the solar system. Projects have also been suggested to place laser aboard Earth satellites nearer to the Sun in order to transform the solar radiation into laser beams, with this transformed energy subsequently transmitted to the Earth or to other space bodies. These projects have not yet been put into effect, because of the great technological difficulties to be overcome and therefore the great cost involved. But here is no doubt that in time these projects will be realized and the laser beam will begin operating in outer space as well.

8.1.4 Look through the text and answer the questions.

1What is this text about?

2What does the word “Laser” mean?

3What is laser: is it a device or some phenomenon?

4Who was the first to write about laser?

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