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Biomedical Engineering

The organelle responsible for producing most of the cell's ATP is the:

Which of the following is NOT a connective tissue?

The sodium-potassium pump transports:

Programmed cell death that occurs without provoking inflammation is called:

DNA replication takes place during which phase of the cell cycle?

A gain-of-function mutation converting a normal gene that promotes cell division into a cancer-driving gene produces a:

Which immunoglobulin class is the only one that crosses the human placenta?

The antibody class produced first and in greatest amount during a primary immune response is:

Immunity acquired by injecting ready-made antibodies is:

T lymphocytes mature in the:

Glucose entering a cell through a GLUT carrier down its concentration gradient without ATP is an example of:

Steroid hormones differ from peptide hormones in that they:

The visible precipitation of a soluble antigen by its antibody occurs optimally at:

Serum differs from plasma in that serum lacks:

The normal life span of a human erythrocyte is about:

Which leukocyte is the most numerous in normal peripheral blood?

Erythropoietin, the hormone stimulating red cell production, is secreted mainly by the:

The extrinsic pathway of coagulation is initiated by:

The laboratory test used to monitor the intrinsic pathway of coagulation is the:

Which clotting factor cross-links fibrin to stabilise the clot?

Citrate and EDTA prevent blood from clotting in a specimen tube because they:

A blood-contacting biomaterial surface such as a catheter or dialysis membrane primarily triggers:

In DNA, adenine pairs with thymine by how many hydrogen bonds?

The start codon of translation, which also codes for methionine, is:

In the polymerase chain reaction, the enzyme that extends the primers at about 72 degrees Celsius is:

The blotting technique used to detect a specific protein is called:

The resting membrane potential of a typical neuron is approximately:

Rapid depolarisation during a nerve action potential is caused by:

Saltatory conduction occurs in myelinated fibres because the impulse:

That a nerve impulse either occurs at full amplitude or not at all is known as:

The neurotransmitter released at the human neuromuscular junction is:

Calcium released from the sarcoplasmic reticulum initiates contraction by binding to:

In the spinal cord, the dorsal (posterior) root carries:

Which part of the brain contains the respiratory and vasomotor centres?

The chief function of the middle-ear ossicles is to:

High-frequency sounds are detected at which part of the basilar membrane?

The greatest part of the refractive power of the human eye is provided by the:

Myopia (short sight) is corrected by which type of spectacle lens?

The region of the retina giving the sharpest vision, packed with cones and containing no rods, is the:

Cardiac output is calculated as:

The natural pacemaker of the heart is the:

The QRS complex of the electrocardiogram represents:

If blood pressure is 120/80 mmHg, the mean arterial pressure is approximately:

According to Poiseuille's law, halving the radius of a vessel increases its resistance by a factor of:

The Frank-Starling law of the heart states that:

Coronary blood flow to the left ventricle occurs mainly during:

Surfactant, which reduces alveolar surface tension, is secreted by:

Which lung volume cannot be measured by simple spirometry?

Vital capacity is the sum of:

An inhaled foreign body is more likely to enter the right main bronchus because it is:

The most powerful normal stimulus to increase ventilation is a rise in:

The oxygen-haemoglobin dissociation curve shifts to the right when there is:

The structural and functional unit of the kidney is the:

The normal glomerular filtration rate in a healthy adult is approximately:

Which substance's clearance is equal to the glomerular filtration rate and is therefore the reference standard?

Plasma albumin does not normally appear in the glomerular filtrate mainly because:

Approximately what proportion of the glomerular filtrate is reabsorbed in the proximal convoluted tubule?

Glucose appears in the urine when the plasma concentration exceeds the renal threshold of about:

Antidiuretic hormone concentrates the urine by:

The hyperosmotic gradient of the renal medulla is created chiefly by the:

Which hormone secreted by the kidney stimulates red blood cell production?

Urine passes from the renal pelvis to the bladder principally by:

Reflux of urine from the bladder back into the ureter is normally prevented by:

The micturition reflex is integrated at which level of the spinal cord?

Urinary tract infections are far more common in women mainly because:

Bone is strongest when loaded in:

The Young's modulus of cortical bone in the longitudinal direction is approximately:

Wolff's law states that:

A spiral fracture of the tibia indicates that the bone was loaded principally in:

Most human joints act as third-class levers, which means that:

During normal walking, the hip joint reaction force is approximately:

The 'toe region' at the start of the stress-strain curve of a ligament corresponds to:

Which property describes the increase in strain of a tendon held under a constant load over time?

The greatest force a skeletal muscle can develop occurs during:

Blood is described as a non-Newtonian fluid because its viscosity:

The single most important determinant of whole-blood viscosity is the:

The Fahraeus-Lindqvist effect describes the fact that the apparent viscosity of blood:

In the design of a blood pump or prosthetic heart valve, regions of very high wall shear stress are avoided chiefly because they cause:

When a cylinder is unrolled (opened in rope form), what shape is formed?

How many transistors does a class B push-pull amplifier use?

In which region does a class B amplifier operate?

Which quantity remains constant (same) throughout a series circuit?

In a star (Y) connected three-phase system, what is the relationship between line voltage (Vₗ) and phase voltage (Vₚₕ)?

What is the primary advantage of CMOS logic technology?

What type of feedback do oscillators use to sustain oscillations?

Which theorem gives the condition for maximum power transfer from a source to a load?

According to Ohm's Law, which relationship is correct?

Three equal resistors in series dissipate 10 W. How much power do they dissipate when connected in parallel (same supply voltage)?

A semiconductor is primarily used for:

Two copper wires of the same length have cross-sectional area ratio 1 : 4. What is the ratio of their resistances (small : large)?

A wire has resistance 40 Ω. Another wire of the same length has 4× the cross-sectional area. What is the resistance of the second wire?

The Superposition Theorem is NOT applicable to which type of circuit analysis?

The current through a capacitor is known as:

A bridge rectifier operating at 50 Hz produces an output of:

An inductor and resistor are connected in series and a DC voltage V is applied. At steady state, what is the current?

Three resistors each of 2 Ω are connected in delta. What is the equivalent resistance between any two terminals?

A 1 Ω resistor is connected in parallel with a 3 Ω resistor. What is the equivalent resistance?

What is the Standing Wave Ratio (SWR) when the reflection coefficient is 0.8?

A transmission line has Z₀ = 50 Ω and termination impedance Za = 75 Ω. What is the SWR and reflection coefficient?

Biocompatibility is best defined as the ability of a material to:

A material that forms a direct chemical bond with bone tissue is described as:

The direct structural and functional connection between living bone and the surface of a load-bearing implant is called:

Which surface analysis technique provides elemental composition together with the chemical bonding state of the outermost few nanometres?

A low water contact angle on a biomaterial surface indicates that the surface is:

The technique that gives three-dimensional surface topography at nanometre resolution and can operate in liquid is:

Which of the following is the principal disadvantage of ceramics as load-bearing biomaterials?

The mismatch in elastic modulus between a metallic implant and bone leads to:

Which class of biomaterial carries the specific risk of disease transmission and batch-to-batch variability?

Surface analysis is emphasised over bulk analysis in biomaterials because:

The series of international standards governing the biological evaluation of medical devices is:

A limitation common to most electron- and ion-based surface techniques when applied to biomaterials is that they:

Which property would be considered the single most important requirement for a material used in a blood-contacting catheter?

The letter L in 316L stainless steel indicates:

Which implant alloy has an elastic modulus closest to that of cortical bone?

The corrosion resistance of titanium implants is due to:

Placing a stainless steel bone plate with titanium screws risks:

Corrosion occurring in the oxygen-depleted, acidified space beneath a screw head is called:

Nitinol is used in self-expanding stents because of its:

In the collagen triple helix, which amino acid must occupy every third position?

A deficiency of vitamin C weakens collagen because vitamin C is required for:

The collagen type found predominantly in hyaline cartilage is:

Glutaraldehyde crosslinking of a bioprosthetic heart valve improves durability but has the drawback of:

Which glycosaminoglycan is non-sulphated and is not covalently attached to a protein core?

The ability of articular cartilage to resist compressive load derives principally from:

Heparin is used to coat blood-contacting devices because it:

The polymer used as the bearing surface in total hip and knee replacements is:

Polymethyl methacrylate bone cement presents which particular hazard during implantation?

Which polymer degrades in vivo by hydrolysis and is therefore used for resorbable sutures and fixation pins?

The glass transition temperature is important in selecting a medical polymer because it determines:

Expanded PTFE is preferred to solid PTFE for vascular grafts because it:

Ceramics are described by Weibull statistics rather than a single strength value because:

The Ca/P molar ratio of stoichiometric hydroxyapatite is:

Bioglass 45S5 bonds to bone because in body fluid it:

Which material is used for the leaflets and components of mechanical heart valves because of its thromboresistance and wear resistance?

Zirconia is tougher than alumina principally because of:

For a unidirectional fibre composite loaded along the fibre direction, the modulus is given by:

Increasing the filler content of a dental restorative composite principally serves to:

A carbon-fibre-reinforced PEEK bone plate is attractive compared with a stainless steel plate because it is:

The principal purpose of surface modification of a biomaterial is to:

A plasma is best described as:

In a cold (non-thermal) plasma:

Treating a polymer surface with an oxygen plasma generally:

A plasma using a fluorine-containing gas such as CF4 is used to make a surface:

The loss of hydrophilicity of a plasma-treated polymer surface over the following days is called:

Hydroxyapatite is most commonly applied to a titanium hip stem by:

Ion implantation is attractive as a surface treatment because it:

Which surface property would be deliberately maximised for the porous region of a cementless hip stem?

Grafting polyethylene glycol chains onto a device surface is done principally to:

Plasma-enhanced chemical vapour deposition is preferred to conventional CVD for polymer substrates because it:

A practical limitation shared by most plasma surface treatments is that they:

A silane coupling agent is used to:

The tripeptide sequence most widely grafted onto biomaterial surfaces to promote cell adhesion is:

Which immobilization method is the simplest and mildest but suffers from leaching of the biomolecule?

Covalent immobilization of an enzyme has the principal disadvantage that:

Entrapping cells in calcium alginate beads has which main limitation?

Microencapsulation of pancreatic islet cells in a semipermeable membrane is designed to:

The binding pair most commonly exploited for orientated affinity immobilization is:

A polyethylene glycol spacer arm is introduced between a support and an immobilized enzyme in order to:

In a classic glucose biosensor, the immobilized biological recognition element is:

Which support material is essential when the transducer of a biosensor is electrochemical?

Crosslinking enzymes to one another with glutaraldehyde without a support has the drawback of:

The main reason for immobilizing heparin on the surface of a dialysis membrane is to:

Correct orientation is particularly critical when immobilizing an antibody because:

Compared with releasing a growth factor into the tissue, immobilizing it on a scaffold offers the advantage of:

The very first event to occur when a biomaterial is implanted in tissue is:

The Vroman effect describes the:

Which adsorbed plasma protein most strongly promotes platelet adhesion to a device surface?

The histological hallmark of the foreign body reaction is the presence of:

A thick fibrous capsule around an implanted glucose sensor is a problem chiefly because it:

Late aseptic loosening of a total hip replacement is most often caused by:

Healthy vascular endothelium resists thrombosis partly by secreting:

Cells attach to the extracellular matrix and to RGD-modified surfaces through receptors called:

Regenerated cellulose haemodialysis membranes were largely abandoned because they:

Phosphorylcholine coatings improve blood compatibility because they:

The concept that host tissue cells and bacteria compete to colonise an implant surface is known as:

Bacteria within a mature biofilm are difficult to eradicate mainly because:

The organism most classically associated with biofilm infection of catheters and prosthetic devices is:

How many NOT gates are required to build a 2:1 Multiplexer?

How many 2-input NAND gates are contained in a standard 7400 TTL IC?

In TTL logic, what is the input voltage range for a logic LOW (active LOW level)?

When an invalid BCD code (1010–1111) is detected and auto-corrected, what value is added?

What is the terminal (reset) state of a MOD-10 (decade) counter?

What is the minimum number of flip-flops (memory blocks) required to build a MOD-6 ripple counter?

An SR flip-flop is also called a:

A JK flip-flop with J = 1 and K = 1 is clocked at 20 kHz. What is the output waveform and its frequency?

What is the duty cycle of an ideal astable multivibrator?

Which of the following is NOT a valid operation of flip-flops?

The TRAP interrupt in 8085 microprocessor is:

Small-Scale Integration (SSI) refers to ICs with how many transistors?

In VHDL, a signal that represents a bus (multi-bit connection) is declared as:

In VHDL, the primary design unit that represents a hardware block's interface (ports and generics) is called:

The shadow mask technique is used in:

Left-shifting an unsigned binary number by 1 bit is equivalent to:

The expression x << 3 is equivalent to:

Which logic gate is commonly used for parity checking and overflow detection?

The principal disadvantage of a mechanical prosthetic heart valve compared with a bioprosthesis is the:

The material used for the leaflets of a modern bileaflet mechanical heart valve is:

Structural failure of a glutaraldehyde-fixed bioprosthetic valve occurs principally through:

Synthetic vascular grafts of less than 6 mm diameter fail mainly because of:

Which material is used for a self-expanding carotid or peripheral artery stent?

The drug carried by a drug-eluting coronary stent acts to:

In the pacemaker code VVI, the third letter indicates that the pacemaker is:

A DDD pacemaker is chosen in preference to a VVI pacemaker mainly because it:

Pacemaker leads are frequently steroid-eluting at the electrode tip in order to:

An inferior vena cava filter is indicated principally when a patient with venous thromboembolism:

The intra-aortic balloon pump inflates:

Helium is used to drive the intra-aortic balloon because it:

In a patient with a modern continuous-flow left ventricular assist device, the commonest site of infection is the:

The bearing surface material in the great majority of total hip and knee replacements is:

PMMA bone cement fixes an implant to bone principally by:

For bone ingrowth into a cementless porous-coated implant to occur rather than fibrous tissue formation, micromotion must be kept below about:

Large-head metal-on-metal hip bearings were largely withdrawn because of:

Increasing the diameter of the femoral head in a hip replacement with a polyethylene liner:

The principal cause of late aseptic loosening of a hip replacement is:

A ceramic-on-ceramic hip bearing offers the advantage of:

Compared with the hip, the knee is mechanically more demanding to replace because its motion involves:

In a posterior-stabilised total knee replacement, the function of the posterior cruciate ligament is replaced by:

Increasing the conformity of a knee articulation lowers contact stress but has the drawback of:

Malalignment of the mechanical axis by a few degrees after total knee replacement is important because it causes:

Gentamicin is sometimes added to PMMA bone cement in order to:

Titanium alloy is preferred for a cementless femoral stem rather than cobalt-chromium mainly because of its:

The preferred material for a long-term indwelling urinary catheter is:

The balloon of a Foley catheter should be inflated with:

A catheter of size 18 French has an external diameter of:

The single most effective measure to reduce catheter-associated urinary tract infection is:

The curled ends of a double-J ureteral stent serve to:

Encrustation of urinary catheters and stents is caused principally by:

The mineral that forms the bulk of catheter encrustation and infection stones is:

A ureteral stent left in place and forgotten for a year is likely to:

Vesico-ureteric reflux may occur in a patient with a double-J stent because the stent:

Silver alloy coating of a urinary catheter is intended to:

A Coude tip catheter is used particularly when:

Polypropylene mid-urethral slings and pelvic meshes have become the subject of regulatory restriction mainly because of:

An artificial urinary sphincter consists of:

The commonest complication of breast implant surgery is:

A breast implant capsule that is firm, visibly distorted and painful is classified as Baker grade:

Cohesive silicone gel is preferred to older liquid gel because it:

BIA-ALCL, a rare lymphoma arising in the implant capsule, has been associated particularly with:

The great practical advantage of hyaluronic acid over permanent dermal fillers is that it:

The most serious complication of facial dermal filler injection is:

A bluish discoloration of the skin after hyaluronic acid filler placed too superficially is called:

Integra, the classic dermal regeneration template, consists of:

The principal limitation of cultured epidermal autograft in a massive burn is that it:

The gold standard for permanent coverage of a full-thickness burn remains:

Resorbable plates and screws are preferred to titanium for craniofacial fixation in young children because they:

A patient-specific cranioplasty implant is most commonly produced by:

In midface and mandibular fracture reconstruction, the reference used to guide reduction is the:

The commonest late complication after implantation of an intraocular lens is:

A square posterior optic edge on a modern intraocular lens serves to:

Which intraocular lens material should be avoided in an eye that may later require silicone oil tamponade?

The power of an intraocular lens is calculated principally from measurements of:

The original intraocular lens material, suggested by the observation that Perspex fragments were well tolerated in pilots' eyes, was:

Intrastromal corneal ring segments are implanted principally to treat:

The principal engineering difficulty with a keratoprosthesis is:

An Ahmed glaucoma valve differs from a Baerveldt implant in that it:

The commonest cause of late failure of a glaucoma drainage device is:

A porous hydroxyapatite orbital implant is preferred to a smooth PMMA sphere because it:

A retinal prosthesis can restore some visual perception only when:

Current retinal prostheses provide vision that is best described as:

An ophthalmic viscosurgical device such as a hyaluronic acid preparation is used during cataract surgery to:

The three essential components of the tissue engineering triad are:

Induced pluripotent stem cells are attractive for tissue engineering because they:

An ideal tissue engineering scaffold should have a porosity of:

For bone tissue engineering, the pore size generally regarded as optimal for cell ingrowth and vascularisation is about:

The degradation rate of a scaffold should ideally be:

Which fabrication technique produces fibres of a diameter comparable to natural extracellular matrix fibrils?

In the basic procedure of tissue engineering, cells are released from a tissue biopsy by:

Dynamic seeding under perfusion is preferred to static seeding because it gives:

The principal function of a perfusion bioreactor in tissue engineering is to:

The single greatest obstacle to engineering thick tissues and solid organs is:

Which tissue has been most successfully engineered and brought into clinical use?

A decellularised donor organ is attractive as a scaffold because it retains:

Mechanical loading is applied to a tissue-engineered tendon or cartilage construct in a bioreactor because:

The continuous spectrum of X-rays produced when electrons are decelerated by the target nuclei is called:

Approximately what percentage of the kinetic energy of the electrons striking the anode is converted into X-rays?

The maximum photon energy in an X-ray beam produced at 100 kVp is:

The line focus principle allows an X-ray tube to have:

The anode heel effect results in radiation intensity that is:

The principal advantage of a rotating anode over a stationary anode is:

Doubling the mAs while keeping kVp constant will:

Total filtration of at least 2.5 mm aluminium equivalent is required above 70 kVp in order to:

The half-value layer of an X-ray beam is a measure of its:

Subject contrast in a radiograph arises principally from differences in:

A grid with a ratio of 12:1 compared with one of 5:1 will:

The use of a radiographic grid becomes appropriate when the body part exceeds about:

Radiation-induced cancer is classified as which type of biological effect?

The Hounsfield unit value of water is defined as:

A region of interest on a CT image measures -100 HU. The tissue is most likely:

Increasing the window width on a CT display will:

In a third-generation CT scanner:

A concentric ring artefact on a CT image is characteristic of:

The technology that made continuous-rotation helical scanning possible is the:

Pitch in helical CT is defined as:

Compared with simple back-projection, filtered back-projection:

Iterative reconstruction is increasingly used in CT principally because it:

If the mAs is quadrupled in a CT acquisition, image noise will be:

Cupping artefact and dark streaks between two dense bones are caused by:

Assigning an intermediate Hounsfield value to a voxel that contains two different tissues is called:

The CT dose descriptor that accounts for the length of the region scanned is:

The nucleus imaged in routine clinical MRI is:

The Larmor frequency of protons in a 1.5 tesla magnet is approximately:

T1 relaxation is defined as the time taken for the longitudinal magnetisation to recover to:

A T2-weighted image is produced using:

On a T1-weighted image, cerebrospinal fluid appears:

Which sequence is used to suppress the signal from cerebrospinal fluid and reveal periventricular lesions?

The MRI sequence that detects acute cerebral infarction within minutes of onset is:

Spatial localisation in MRI is achieved by:

The central region of k-space predominantly determines the image's:

Gadolinium-based contrast agents make enhancing tissue appear bright on T1-weighted images because they:

Gadolinium contrast should be used with particular caution in patients with:

A 180 degree refocusing pulse is used in a spin echo sequence in order to:

The most serious immediate physical hazard in the MRI environment is:

The speed of sound assumed by a diagnostic ultrasound machine in soft tissue is:

An echo returns 13 microseconds after the pulse was transmitted. The reflecting interface lies at a depth of approximately:

Coupling gel is essential in ultrasound scanning because:

Increasing the transducer frequency from 3 MHz to 10 MHz will:

The backing (damping) block behind the piezoelectric element serves to:

Axial resolution in ultrasound is equal to:

Bright echoes appearing deep to a fluid-filled cyst are an example of:

Which imaging mode displays the motion of a structure along a single line against time?

The Doppler shift is zero when the angle between the ultrasound beam and the direction of blood flow is:

For accurate quantitative velocity measurement in Doppler ultrasound, the angle of insonation should be kept below:

Aliasing in pulsed-wave Doppler occurs when the Doppler shift exceeds:

Power Doppler differs from colour Doppler in that it:

The mechanical index displayed on an ultrasound machine indicates the likelihood of:

In a digital image, the number of grey levels available is determined by the:

Computed radiography uses an imaging plate made of:

In a computed radiography reader, the imaging plate is scanned by a red laser and emits:

Direct conversion digital radiography detectors use:

The principal workflow advantage of DR over CR is that DR:

Dose creep in digital radiography refers to:

Detective quantum efficiency describes how well a detector:

In digital subtraction angiography, the mask image is:

The universal standard governing the format and exchange of medical images is:

Which system holds patient scheduling, worklists and radiology reports rather than the images themselves?

A DICOM file differs from an ordinary image file in that it also contains:

A major practical benefit of PACS in a country with difficult geography such as Nepal is:

Diagnostic display monitors in a PACS must be calibrated to:

The unit of radioactivity, equal to one disintegration per second, is the:

Which radionuclide accounts for the great majority of diagnostic nuclear medicine studies?

Technetium-99m is obtained in the hospital by elution of a generator containing:

The photon energy emitted by technetium-99m is:

Which type of radiation is of no use for imaging because it is stopped within a fraction of a millimetre of tissue?

The two photons detected in PET are produced by:

PET has much higher sensitivity than SPECT principally because it:

The commonest PET radiopharmaceutical, a glucose analogue trapped inside metabolically active cells, is:

The component of a gamma camera that determines its spatial resolution and rejects photons not travelling in the required direction is the:

The scintillation crystal of a conventional gamma camera is made of:

The pulse height analyser in a gamma camera is used to:

If a radionuclide has a physical half-life of 6 hours and a biological half-life of 3 hours, its effective half-life is:

The principal advantage of hybrid PET/CT over PET alone is that the CT provides:

The typical amplitude of a surface electroencephalogram signal is:

Silver/silver chloride is the preferred material for biopotential electrodes because it is:

The most important amplifier characteristic for rejecting 50 Hz mains interference in an ECG is a high:

The driven right-leg circuit in an electrocardiograph is used to:

The current that may cause ventricular fibrillation when applied directly to the heart through an intracardiac catheter is as little as:

At a standard paper speed of 25 mm/s, one small 1 mm square of ECG paper represents:

According to Einthoven's law, the relationship between the bipolar limb leads is:

Alpha rhythm in the electroencephalogram has a frequency of:

EEG electrodes are positioned according to the:

A transducer that requires no external excitation because it generates its own output is:

The gauge factor of a metal foil strain gauge is approximately:

A linear variable differential transformer measures displacement with the advantage of: