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The correct choice is (b) False

Easy EXPLANATION: False, the major PROBLEM encountered with the sinusoidal type of magnetic field is that the blood vessel and the fluid contained in it act as the secondary coil of a transformer when the probe magnet is excited. As a RESULT, in addition to the induced flow VOLTAGE, there is an induced artefact voltage generally REFERRED to as ‘transformer voltage’.

Right CHOICE is (B) Negative

Explanation: DC amplifiers are generally of the negative FEEDBACK type. They are not practical for very low level applications because of dc drift and poor common-mode REJECTION capabilities. They are used for medium gain applications down to about 1 mV signal levels for full scale.

Right ANSWER is (c) 15 cm/s

The EXPLANATION is: For designing the probe, velocity for the cardiovascular system is taken as 15 cm/s. For non-cannulated probes, a uniform magnetic field over the measuring area is so selected that it has a convenient SHAPE and the SMALLEST size (CUNNINGHAM et al. 1983).

Correct option is (a) dc AMPLIFIERS

The best explanation: AC amplifiers have a limited frequency response and are, therefore, used only for special MEDICAL applications such as electrocardiograph machine. For electrocardiograms, an ac amplifier with SENSITIVITY, giving 0.5 mV/cm, and frequency response up to 1 kHz and an input impedance of 2 to 5 MW is used. For such applications as retinography, EEG and EMG, more sensitive ac amplifiers are required, giving a CHART sensitivity of say 50 mV/cm with a high input impedance of over 10 MW.

Correct CHOICE is (b) bone

The explanation: Biological soft TISSUES are nonlinear, anisotropic, fibrous composites, and a detailed description of their behavior is the subject of active research.Hard tissue, mineralized tissue, and calcified tissue are often used as synonyms for bone when describing the structure and properties of bone or tooth. One can SEPARATE these tissues based on their mode of loading: cartilage is generally LOADED in compression; tendons and LIGAMENTS are loaded in tension, and muscles generate active tension.

Correct option is (c) Rt = RO(1+ɑt)

To EXPLAIN I would SAY: The resistance Rt of a metallic conductor at any temperature t is given by Rt = Ro(1+ɑt). Ro is the resistance at 0*C. ɑ is a temperature COEFFICIENT of resistivity.

Right answer is (b) Laser Doppler

To explain: Laser Doppler flowmetry is a non-invasive technique and SEEMS to offer several advantages like light reproducibility and sensitivity. However, its disadvantages like poor SELECTIVITY, baseline instability and restriction in a site of measurement are still LIMITING FACTORS in its SUCCESSFUL clinical utilization.

Right OPTION is (d) 5 mW

Easy explanation: In principle, light from a low POWER (5 mW) He–Ne laser is coupled into a quartz fibre and transmitted to the skin. The light is reflected from both the non-moving tissues (reference BEAM) and moving red BLOOD cells (Doppler-shifted beam). The two beams are received by a plastic fibre and transmitted BACK to a photo-diode where optical heterodyning takes place.

Right option is (c) Concentration error

The BEST I can explain: There are a NUMBER of errors that may OCCUR in the electronic cell COUNTING technique. Briefly, these errors are categorized as follows:

Aperture Clogging, Uncertainty of Discriminator THRESHOLD, Coincidence Error, Settling Error, Statistical Error, Error in Sample Volume, Error due to Temperature Variation, Biological Factors, Dilution Errors, Error due to External Disturbances.

Correct answer is (c) coulter Counter

The explanation: Blood cell counters, operating on the principle of conductivity change, which occurs each TIME a cell PASSES through an orifice, are generally known as Coulter Counters. The method was patented by Coulter in 1956 and it forms the basis of SEVERAL particle counting instruments manufactured by a number of firms throughout the world.

Right option is (c) thermo-motive

Easy explanation: When two wires of different material are joined TOGETHER at either ends, forming two JUNCTIONS which are maintained at a different temperature, a thermo-motive force is generated causing a current to FLOW around the circuit. This arrangement is CALLED a thermocouple. The junction at a LOWER temperature in the thermocouple is called the reference temperature. The junction at a higher temperature in thermocouple is termed as measuring junction.

Right choice is (d) Laser Doppler Blood Flowmeter

Explanation: A system utilizing the Doppler-shift of monochromatic laser light to measure blood flow in the SKIN is described by Watkins and Holloway (1978). When a laser beam is DIRECTED towards the tissue under study, absorption and scattering take PLACE. Radiation scattered in MOVABLE structures, such as red cells, is shifted in frequency due to the Doppler effect, while radiation scattered in nonmoving soft tissue is unshifted in frequency.

Right option is (c) NMR

For explanation: NUCLEAR magnetic RESONANCE principle offers YET another non-invasive method for the measurement of peripheral blood flow or blood flow in various organs. The method pertains to a quantum mechanical PHENOMENON related to the magnetic energy levels of the nucleus of some elements and their isotopes.

The correct option is (c) A three-colour flying spot-scanner

For explanation I would say: Miller (1976) describes a differential WHITE blood cell classifier based upon a three-colour flying spot-scanner approach. It utilizes RECOGNITION PARAMETERS based on the principle of geometrical probability FUNCTIONS, which are generated at high speed in a dedicated computer.

Correct choice is (c) 34-50 sec

The EXPLANATION: All the directly MEASURED parameters are measured in triplicate and the average results are displayed. All the 14 parameters are obtained from 1 ML of whole blood in 34–50 s depending on the number of PLATELETS present.

Correct ANSWER is (d) repeatability

Explanation: ABILITY of the sensor to repeat a measurement when put back in the same environment is called repeatability. The threshold of the TRANSDUCER is the smallest change in measurant that will result in a measurable change in the transducer output. The region in which the output does not change with an INCREASE in input is called saturation.

The correct OPTION is (b) CEPSTRUM coefficient and Dynamic time warping

To explain I would say: This algorithm may also be used for arrhythmia detection by SIMPLY checking the difference of R-R wave intervals through signal feature extraction comparison for a CERTAIN period of time. Jen and Hwang proposed a new algorithm using cepstrum coefficient and the dynamic time warping techniques to obtain the long term ECG signal feature and EXTRACT the meaningful information hiding in the QRS complex.

Right option is (d) higher capacitance

Explanation: To ACHIEVE the low frequency response required for medical applications, the amplifier MUST have large values of coupling capacitance.The response should be down to LESS than one hertz which is a very frequent requirement. In all RC-coupled amplifiers, low frequency response is limited by the reluctance of the coupling capacitors.

The CORRECT option is (c) STRAIN gauge

To explain: Strain gauge transducer is an active transducer. Its working PRINCIPLE is based on change in RESISTANCE. Ultrasonic transducers need power to operate. So do the IR sensors and DOPPLER effect transducers.

Correct option is (c) Electromagnetic Blood Flowmeter

Easy explanation: The most commonly used instrument for the measurement of blood FLOW is of the electromagnetic type. With this type of instrument, blood flow can be measured in intact blood VESSELS without cannulation and under conditions which would otherwise be impossible. However, this method REQUIRES that the blood VESSEL be EXPOSED so that the flow head or the measuring probe can be put across it.

Right ANSWER is (b) Ultrasonic

The best I can EXPLAIN: Ultrasonic is a non-invasive technique to measure blood VELOCITY in a PARTICULAR vessel from the surface of the body. It is based on the analysis of echo signals from the erythrocytes in the vascular structures. Because of the Doppler effect, the frequency of these echo signals changes relative to the frequency which the probe transmits.

Right option is (d) Setting of the threshold level control

For EXPLANATION: The calibration factor is constant for GIVEN aperture SIZE, electrolyte resistivity and amplifier gain setting. It is USED for the conversion of threshold settings to particle VOLUMES or their cube roots to equivalent spherical diameters.

The correct option is (d) RHYTHM definition

The explanation: In automated arrhythmia monitoring SYSTEM, Rhythm definition is PERFORMED after the Ventricular fibrillation detection. Rhythm definition is also performed after the beat labeling and ATRIAL fibrillation detection in automated arrhythmia monitoring and analysis system.

The CORRECT choice is (a) True

For explanation I would SAY: It is True. BONES are living tissues. hey also are responsible for the production of blood cells and act a MINERAL reservoir in the body. They keep GROWING. They also play the role of protection of internal soft organs like the brain is protected by skull and lungs and heart by the rib cage.

The CORRECT choice is (d) HIGH pass filter

Best explanation: Low pass filter amplifies signals below a certain FREQUENCY. High pass filter amplifies signal above a certain frequency. Band pass filter amplifies FREQUENCIES within a certain band. Band stop filter amplifies all the frequencies except those in a certain band.

Right answer is (b) resistance temperature detector

For explanation I would SAY: It is a passive SENSOR and requires CURRENT excitation to produce an OUTPUT voltage. RTD has very low temperature coefficient.RTD stands for Resistance Temperature Device. Voltage drop across RTD is much LARGER than the thermocouple output voltage.

The correct answer is (C) 106

To explain I would say: The preamplifier USED by Goodman (1969(a)) has a CMRR of 106 dB (200,000 : 1) with a common mode input impedance of 150 MW. The preamplifier GAIN is of the order of 1000. The preamplifier also must incorporate the facility for ‘probe balance’ by which signals in phase with the magnet current can be selected to balance background voltages in phase with flow voltages.

Right choice is (c) platinium

For explanation: In actual practice, the electromagnetic flowmeter transducer (Wyatt, 1984) is a tube of non-magnetic MATERIAL to ensure that the magnetic flux does not bypass the flowing LIQUID and go into the WALLS of the tube. The tube is made of a conducting material and generally has an insulating LINING to PREVENT short circuiting of the induced emf. The induced emf is picked up by point electrodes made from stainless steel or platinum.

Right option is (a) Less than 1%

Best explanation: SETTLING Error: This error arises due to the settling of the PARTICLES in the SOLUTION, with the result that the measurements SHOW a decreasing tendency with time. If the readings are taken within 4–5 min., the settling error is less than 1%.

The correct choice is (b) Frequency DOMAIN analysis

Explanation: Ventricular fibrillation is USUALLY DETECTED by frequency domain analysis.It can be distinguished from noise by appropriately designing band-pass filters.The system is characterized as a narrow-band, LOW frequency signal with energy concentrated in a band around 5-6 HZ.

Correct choice is (c) If it is LESS than 85% of the predicted interval

The best I can explain: In timing CLASSIFICATION, the observed R-R interval is compared to an ESTIMATE of the expected R-R interval. An R-R interval will be declared premature if it is less than 85% of the predicted interval. SIMILARLY, an R-R interval is long if it is greater than 110% of the predicted value.

Right option is (b) Photo diode

Explanation: In principle, light from a LOW power (5 mW) He–Ne laser is coupled into a quartz fibre and TRANSMITTED to the skin. The light is reflected from both the non-moving TISSUES (reference beam) and moving red blood cells (Doppler-shifted beam). The TWO beams are received by a plastic fibre and transmitted back to a photo-diode where optical heterodyning TAKES place.

Right option is (b) 1 to 8.2 mm

To explain: Iron CORED electromagnets are used in PROBES having a diameter between 1 to 8.2 mm, and air cored electromagnets are used in diameters above 8.2 mm. Cannulated probes for extracorporeal use can have greater field strengths and MAGNET size as the constraint of small size is no longer PRESENT.

Correct option is (c) 30

The explanation: The preamplifier used by Goodman (1969(a)) has a CMRR of 106 dB (200,000 : 1) with a common mode input impedance of 150 MW. The preamplifier gain is of the order of 1000. The preamplifier also must incorporate the FACILITY for ‘probe balance’ by which signals in phase with the magnet current can be selected to balance background voltages in phase with flow voltages. A calibrating signal of 30 mV amplitude can be CONNECTED to the preamplifier with an input SELECTOR switch.

Right choice is (b) False

To explain: False, The operating principle UNDERLYING all electromagnetic type flowmeters is based upon Faraday’s law of electromagnetic induction which STATES that when a conductor is moved at right angles through a magnetic FIELD in a direction at right angles both to the magnetic field and its LENGTH, an emf is INDUCED in the conductor. In the flowmeter, an electromagnetic assembly provides the magnetic field placed at right angles to the blood vessel in which the flow is to be measured.

The CORRECT answer is (d) 10000

Explanation: With some instruments, a correction CHART is available to allow the correct number to be determined. Under a total count of 10,000 pulses, PRIMARY coincidence is NEGLIGIBLE and can be IGNORED.

The correct CHOICE is (c) passing to the skin

Explanation: This TERM generally USED with the type of surgical instrument to be used. It is also used to describe the interaction of rehabilitation DEVICES. Transcutaneous means passing to the skin.

The correct option is (d) Cathode Ray Oscilloscope

The EXPLANATION: Cathode ray oscilloscopes are widely used for the display of waveforms ENCOUNTERED in the medical field. These waveforms can be recorded from the CRO SCREEN by running a photographic film through a recording camera fixed in front of the screen. Recorders are either of the single channel TYPE or of the type which record several channels simultaneously.

Correct ANSWER is (b) Photodetector

The BEST I can explain: The photodetector functions as a square law DEVICE and gives out current, which is proportional to the intensity of the incident light and, therefore, to the frequency of beating of the shifted and unshifted signals. The light falling on the photodetector is an optically MIXED signal involving a Doppler-shifted signal back scattered from the moving red blood cells with the ‘reference’ signal reflected from the non-moving skin surface.

Right option is (c) He-Ne

For EXPLANATION: In principle, LIGHT from a low power (5 mW) He–Ne laser is coupled into a quartz fibre and transmitted to the skin. The light is reflected from both the non-moving tissues (reference beam) and moving red blood cells (Doppler-shifted beam). The two beams are received by a plastic fibre and transmitted BACK to a photo-diode where optical heterodyning takes PLACE.

The correct option is (c) diameter of BLOOD vessel

Easiest explanation: The magnitude of the voltage picked up is directly PROPORTIONAL to the strength of the magnetic FIELD, the diameter of the blood vessel and the VELOCITY of blood flow, i.e. e = CHVd, where e = induced voltage, H = strength of the magnetic field, V = velocity of blood flow, d = diameter of the blood vessel and C = constant of proportionality.