BE/B Eng Bachelor of Engineering Bachelor of Biomedical Engineering 3 — Questions and Answers
Question 1: Which material property is most critical when selecting a polymer for a long-term implantable cardiovascular device?
- High water absorption rate
- Biostability and resistance to degradation in vivo (Correct answer)
- High degree of biodegradability
- Low modulus of elasticity matching cortical bone
Correct answer: Biostability and resistance to degradation in vivo
Long-term cardiovascular implants require materials that are biostable—resistant to hydrolysis, oxidation, and enzymatic degradation—to maintain mechanical integrity over years of use.
Question 2: In a clinical trial for a novel medical device, what is the purpose of a 'control group'?
- To receive the maximum experimental dose of the device being tested
- To provide a baseline for comparison so that the device's effect can be isolated (Correct answer)
- To validate the device's software algorithm in a laboratory setting
- To ensure regulatory compliance with ISO 14971 risk management standards
Correct answer: To provide a baseline for comparison so that the device's effect can be isolated
A control group receives a standard treatment, placebo, or sham procedure, allowing researchers to attribute observed differences in outcomes specifically to the experimental device.
Question 3: A piezoelectric sensor used in an ultrasound transducer converts energy between which two domains?
- Thermal energy and electrical energy
- Mechanical energy (pressure) and electrical energy (Correct answer)
- Magnetic energy and acoustic energy
- Chemical energy and optical energy
Correct answer: Mechanical energy (pressure) and electrical energy
Piezoelectric materials generate an electrical voltage when mechanically deformed (direct effect) and deform when a voltage is applied (converse effect), enabling both transmission and reception of ultrasound waves.
Question 4: What is 'hemolysis' and why is it a critical concern in the design of blood-contacting devices?
- Clot formation on device surfaces, which can occlude blood flow
- The destruction of red blood cells with release of hemoglobin, indicating device-induced blood damage (Correct answer)
- An inflammatory response characterized by white blood cell adhesion to a device surface
- Protein adsorption to a device surface that triggers coagulation cascades
Correct answer: The destruction of red blood cells with release of hemoglobin, indicating device-induced blood damage
Hemolysis is the rupture of red blood cells, releasing hemoglobin into plasma; in blood-contacting devices like pumps and oxygenators, shear stress from fluid dynamics can cause this damage, impairing oxygen transport.
Question 5: In the context of the Hodgkin-Huxley model, what do the variables 'm', 'h', and 'n' represent?
- Membrane capacitance, ion channel resistance, and leak conductance
- Activation and inactivation gating variables for Na⁺ channels and activation gating for K⁺ channels (Correct answer)
- Myelination factor, saltatory conduction velocity, and node density
- Maximum conductance values for sodium, potassium, and chloride
Correct answer: Activation and inactivation gating variables for Na⁺ channels and activation gating for K⁺ channels
In the Hodgkin-Huxley model, 'm' and 'h' are voltage- and time-dependent gating variables governing sodium channel activation and inactivation, respectively, while 'n' governs potassium channel activation.
Question 6: Which imaging modality uses radiofrequency pulses and a strong magnetic field rather than ionizing radiation to generate images?
- Computed Tomography (CT)
- Positron Emission Tomography (PET)
- Magnetic Resonance Imaging (MRI) (Correct answer)
- Fluoroscopy
Correct answer: Magnetic Resonance Imaging (MRI)
MRI uses a strong static magnetic field to align nuclear spins and radiofrequency pulses to perturb them; the signal emitted during relaxation is used to construct images without exposing the patient to ionizing radiation.
Question 7: According to Darcy's Law applied to biological tissues, which parameter describes the resistance of a tissue to fluid flow?
- Hydraulic conductivity (Correct answer)
- Diffusion coefficient
- Partition coefficient
- Osmotic reflection coefficient
Correct answer: Hydraulic conductivity
Hydraulic conductivity (or hydraulic permeability) quantifies how easily fluid passes through a porous medium like tissue under a pressure gradient; lower values indicate greater resistance to flow.
BE/B Eng Bachelor of Engineering Bachelor of Biomedical Engineering 3
Which material property is most critical when selecting a polymer for a long-term implantable cardiovascular device?