BENG 2800 Exam Questions
T
T/F PDI generally increases via hydrolysis breakdown of random polymer backbone covalent bonds
b
which of the following best describes PTFE? a) thermoset elastomer b) thermoplastic c) thermoplastic elastomer d) thermoset e) none of the above
a
which of the following materials would NOT be a good candidate for ethylene sterilization? a) low molecular weight PLGA b) commercially pure titanium c) any polymer d) alumina e) bioglass
d
which statement best describes the initial plastic deformation of semi-crystalline polymers consisting of crystalline lamellae connected by amorphous tie chains? a) plastic deformation begins with shear of the crystalline lamellae b) amorphous tie chains and crystalline lamellae shear simultaneously c) separation of crystalline lamellae occurs before the amorphous tie chains d) amorphous tie chains elongate before the crystalline lamellae e) plastic deformation is not significantly related to the crystallinity of a polymer
b
which statement describes the polyurethanes that are thermoplastic elastomers? a) covalently crosslinked back copolymers that cannot be processed with heat b) block copolymers with hard segments and rubbery segments c) branched homopolymers with low Tg d) covalently crosslinked random copolymers that can be processed with heat e) none of the above
d
Atomic Force Microscopy (AFM), Contact Angle, and Electron Spectroscopy for Chemical Analysis (ESCA) are testing methods used for biomaterials. Which of the following statements best describes this testing? a) these tests provide dynamic and static thermal properties b) these tests provide dynamic and static bulk mechanical properties c) these tests provide bulk material compositional analysis d) these measurements are used for surface characterization e) none of the above
c
Differential Scanning Calorimetry (DSC) is used to test thermal properties for a material. Which of the following is true for this method? a) theorizes the atomic bond strength b) measures material the elastic energy c) determines the rate of heat transfer comparing a sample to a reference material d) determines the maximum stress of a material e) calculates deformation energy
c
Nitinol is pseudo equiatomic alloy of which two metals? a) nickel and aluminum b) nickel and iron c) titanium and nickel d) nickel and bronze
d
Nitinol's low temperature phase structure and high temperature phase structure are respectively known as: a) martenite and arborite b) austenite and malachite c) hittite and jebusite d) martensite and austenite
F
T/F biological or cellular interaction with an implanted biomaterial is governed by direct interaction with the material surface
T
T/F both blood coagulation and thrombus breakdown are vital aspects of material hemocompatibility
F
T/F bulk erosion of water-soluble materials more likely results when the rate of water infiltration into the interior of a material is significantly hindered
T
T/F degree of hydrophobicity is generally a critical factor for degradation processes
T
T/F enhancement of biocompatibility of materials is dominated by the area of cell-biomaterial interactions
F
T/F ethylene oxide is toxic, carcinogenic, and not very explosive
T
T/F increasing the molecular weight of a polymer generally increases the strength of a polymer but with the drawback of more difficult processability
F
T/F material compatibility is always binary in nature
T
T/F medical device packaging is an important aspect for sterilization as well as marketing
F
T/F platelets are extremely firm and stable structures that require significant stimulation
F
T/F poly(lactic acid) and poly(glycolic acid) are examples of hydrolytic degradable biopolymers that are FDA pre-approved for medical device applications
T
T/F proteins have the ability to conform to the biomaterial to gain affinity for the material
T
T/F response of proteins to surface can be very dynamic with competition between proteins for surface coverage
d
WintersGel, a lightly crosslinked polymer used for prosthetic applications, is what class of biomaterial polymer? a) expanded fluoropolymer b) amorphous acrylic c) polyurethane block copolymer d) silicone thermosetting elastomer e) none of the above
the formation of a bead means the material is hydrophobic and is not conductive to the aqueous environment of contact lens. Also, since the body is temperature is 37C and therefore greater than 30C, the material would be melted and again not suitable for a contact lens
a 1 mL drop of distilled water is dropped onto a flat plate of a biomaterial and the water droplet is observed to form a bead. The Tm for the biomaterial is found to be 30C. Describe the applicability of using this material for a contact lens
d
a biocompatible substance which is used to replace or assist part of an organ or its tissue, while in intimate contact with living tissue is known as a) biological material b) pharmaceutical c) surrogate material d) biomaterial e) biomedical material
d
a full description of elasticity of a material should include both a) wear the elastic strain b) elastic modulus and maximal elastic elongation c) yield strength and plastic stretchability d) resilience and maximal elastic elongation e) elastic modulus and yield strength
d
a material that is conductive, tough, ductile, and strong best describes what materials? a) polymers b) composites c) ceramics d) metals e) living tissue
biocompatibility is the ability of a material to perform with an appropriate host response in a specific application. Using this metal for heart valve implant causes calcification, which is NOT an appropriate host response. But for another application, for instance, bone implant device, the calcification would be an appropriate response
a metal that leads to calcification hardening would be a deleterious trait as a heart valve replacement. Using the definition of a biocompatibility, briefly explain whether this material should ever be considered as a material for an implant in the body
a and b
a polymer molecular weight distribution with a few fractions of extremely high molecular weight chains will significantly increase which of the following calculations: a) PDI b) Mw c) Mn d) all of the above e) none of the above
c
a polymer reaction that consists of initiation, propagation, and termination is described as a) X-mer + Y-mer --> (X+Y)-mer b) condensation reaction c) chain reaction d) stepwise reaction e) none of the above
d
a polymer sample has a crystallinity of 80%. The density of the amorphous structure of this polymer is 0.85 g/cm^3 whereas the density is 0.98 g/cm^3 for the crystalline structure. Which of the following statements is true? a) the density of the sample is dependent on the density of crystalline structure but independent of the density of the amorphous structure b) the density of the sample is less than 0.85 g/cm^3 c) the density of the sample is independent of the density of both the amorphous and the crystalline structures d) the density of the sample is less than 0.98 g/cm^3 e) the density of the sample is equal to 80% of the density of the amorphous structure
a, c, and e
annealing is a heat treatment to increase ductility and toughness while reducing internal stresses. Which of the following are steps of the process of annealing? a) controlled cooling or "quenching" b) drying thoroughly c) heating to the required temperature d) freezing rapidly e) "soaking" at a maintained temperature
c
bone ingrowth into a porous insert implant that mechanically attaches the bone to the material is known as: a) morphological fixation b) bioactive fixation c) biological fixation d) adsorption fixation e) enhanced mechanical fixation
Advantages: -cold working methods generally add line defects to the materials and make the metal stronger and with better surface finishes (less surface oxidation) -cold working allows for machining to more exact dimensions Disadvantages: -cold working methods require much energy and hence generally more difficult -cold working reduces the ductility of the metal
briefly describe 2 advantages and 2 disadvantages for cold working a metal
1. topography- increased texture means more surface area 2. composition- chemical makeup determines intermolecular forces 3. hydrophobicity- hydrophobic surfaces generally bind more proteins 4. heterogeneity- non-uniformity can result in domains with potentially differing interactions 5. surface potential- potential influences the ions in solutions and the surface
briefly describe 3 of the 5 surface properties that affect interactions with proteins
1. low molecular weight 2. high number of cleavage sites and high functional reactivity 3. low crosslinking, amorphous structure and low Tg (below body temperature) 4. high surface area to volume ratio and hydrophilic nature
briefly describe 4 methods to design a bioeroding polymer with fast hydrolysis
advantage: the large interfacial area provides a site for the cells to growth and the optimal pore size still allows for adequate blood supply disadvantage: the higher the porosity, the lower the overall strength of the bone
briefly describe one advantage and disadvantage for designing a bone implant with large porosity
-the shown aortic aneurysm results from a weakening of the vessel that can eventually rupture. The stent provides a new internal pathway for blood flood reducing the stress on the vessel wall and preventing further bulging -the stent is made from a nitinol wire mesh along with a fabric such as a synthetic ePTFE -the spring-like elasticity of the nitinol will expand the stent. Hence, it has to be implanted by first having contained in a plastic tubing device and then withdrawing the tubing as the stents self expand
briefly describe the following for a thoracic stent medical device: a) primary purpose b) biomaterials c) how it is implanted compared to a typically cardiovascular stent
the primary function concept for a bioerodible polymer is that it functions temporarily in the body until the body no longer the device. As such, the rate of polymer degradation should closely match the rate of the body stress response. For instance, internal dissolving sutures much function with appropriate tensile strength holding the tissue together until its regrowth is inherently strong enough
briefly describe the primary functional concept of designing a bioerodible polymer and include an example
this discovery demonstrated the "bio-tolerability" of foreign materials in the body
briefly describe the significance to biomaterial science by the remains of "Kennewick Man" with an embedded spear point in hip that was not the cause of death
tendons have a great amount of strength due to its supramolecular structural composition of "hierarchical structure". Chains are wound into triple helices and then bound into collagen fibrils and finally into collagen fibers
briefly explain the strength of tendons in the body that are made of collagen fibers from a structural perspective
a
ceramics are used in medical applications such as a) dental implants b) machining c) special applications d) artificial skin
a
cold working strengthens materials by creating a) line defects b) fold defects c) strain lines d) point strain
- thermoplastics are polymers that become soft and moldable when heated the appropriate temperature and then solidify once cooled. On a molecular basis, the thermal energy is breaking enough light secondary bonds to for the macromolecules to rearrange. Reheat and cooling process is often repeatable without significant loss - on the other hand, thermoset polymers are those that cannot be melted when heated. On a molecular, thermosets are highly chemically crosslinked macromolecules that cannot slide past each other with the crosslinking resulting during an irreversible curing reaction
describe both thermoplastic and thermoset polymers an explain their respective attributes on a chain molecular basis`
higher crystalline polymers are generally more ordered, compact and have higher bond secondary bond strength. This leads to the following properties: - glassy, hard, brittle substance with high Young's modulus and low elasticity - generally more hydrophobic with less water infiltration -higher density
describe how/why high crystallinity generally affects the physical properties of hardness, hydrophilicity and density for a polymer
1. packaging is important as well as loading 2. longer processing times 3. humidity and temperature can affect material compatibility 4. contact/diffusion of gas throughout the device 5. toxicity and exclusivity dangers of EO gas
describe three disadvantages for ethylene oxide terminal sterilization
risk management includes mitigating risk. From a materials standpoint, this typically means understanding and reducing risk associate with materials failure such as corrosion, fracture, etc. Essentially this includes designing the risk material for the given function such as a strong metal for a load bearing design rather than a soft polymer
explain how risk management is important to biomaterials
a multi-biomaterial is a medical device that is composed of two or more different materials as parts with separate functions such as artificial hip that has a metal femoral rod stem and a ceramic ball. A composite biomaterial is when two or more materials are blended in a way to create a new material with superior properties than those of the individual components
explain the difference between and multi-biomaterial versus a composite biomaterial within a medical device
b
high density, high purity Al2O3 is used as a biomaterial for moving surfaces of total joint replacement devices. Which of the following statements is NOT a reason for why it is used in this application? a) excellent corrosion resistance b) high surface roughness and large grain dispersion c) high compressive strength d) good biocompatibility e) none of the above
b
hot working of a metal is defined as the temperature being greater than approximately which percent of the melt temperature? a) 10% b) 30% c) 50% d) 70% e) 90%
d
how much water must a hydrogel contain to be considered a super absorbent hydrogel? a) 10% b) 60% c) 85% d) 95%
c
inorganic structures vary between glass, ceramics, and glass-ceramics based on all of the following except: a) processing time b) thermal processing c) wet bulb temperature d) composition of phase structures
1. good corrosion resistance due to stable titanium dioxide (TiO2) layer 2. accepted as "bioinert" with treatment methods to improve osteointegration 3. lower elastic modulus that is a relatively close match with bone tissue in comparison with other metal alloys
list the 3 primary reasons why titanium or titanium alloys are good biomaterials for orthopedics
1. polymers-oxidation 2. ceramics-brittleness 3. metals-corrosion
list the three general classes of materials used as biomaterials and the respective most common problem with each class
d
metal powders are used to create textured surfaces for some orthopedic implants. Heating a metal powder until it coalesces into a solid or porous mass without liquefaction is known as what process? a) hot working b) melting c) annealing d) sintering
a
polyurethanes were originally developed in the 1930s to compete with which of the following materials: a) nylons b) biodegradable polyesters c) silicones d) acrylics e) fluorinated biomaterials
c
radiation accounts for approximately what percent of the terminal sterilization market? a) 10% b) 20% c) 50% d) 60% e) 80%
c
random hydrolytic breakdown of polymer backbone with an initial PDI of 1 would result in which of the following a) decrease in PDI b) increase in molecular weight c) increase in PDI d) increase in crystallinity e) none of the above
a
repeated cycle testing until failure occurs is referred to as: a) fatigue testing b) ultimate strength testing c) breaking strength testing d) failure replication e) destructive analysis
e
stainless steel is an alloy of that is comprised primarily of what metal a) nickel b) titanium c) chromium d) cobalt e) iron
d
tensile testing on a "dog-bone" shaped biomaterial sample is performed on an Instron mechanical testing machine and exhibits the following behavior from its initial (1) to intermediate (2) to final stage (3). Which of the following can be considered to be true statements? a) the testing indicates plastic deformation from (1) to (2) and elastic deformation from (2) to (3) b) the testing indicates from plastic deformation from (1) to (2) and from (2) to (3) c) the testing indicates elastic deformation from (1) to (2) and plastic deformation from (2) to (3) d) the testing indicates elastic deformation from (1) to (2) and from (2) to (3) e) the testing indicates neither plastic nor elastic deformation
negative outcomes: the materials and devices led to unanticipated results and complications for the patients as this became a de facto human clinical trial positive outcomes: this practice led to many important discoveries regarding biomaterials and these could be shared with health care and scientific communities. The results helped bring about regulatory approval for human use
the "surgeon hero" such as Sir Harold Ridley with his invention of intraocular lens used available materials as needed to create medical devices. From the class discussions, name one positive and one negative outcome of this bold practice
c
the Polydispersity Index (PDI) is a measure of the ____ of a polymer distribution and is defined by ____ a) disparity, Mn/Mw b) uniformity, Mn/Mw c) uniformity, Mw/Mn d) reactivity, EwiMi e) reactivity, Mw/Mn
e
the bulk mechanical property related to value of the nominal strain required to break a material is known as a) UTS b) resilience c) Elastic Modulus d) elasticity e) ductility
d
the figure depicts the relationship between molecular weight and reaction conversion for which polymerization polymers? a) addition polymers b) chain reaction polymerization c) radical polymerization d) stepwise reaction e) none of the above
c
the following polymer description is an example of a a) a block copolymer b) an alternating copolymer c) a homopolymer d) graft copolymer e) crosslinked polymer
b
the following scheme describes what polymer synthesis where the chain is getting successively longer? a) stepwise reaction b) addition polymer c) polycondensation d) adduction polymer e) none of the above
d
the stress-strain curve time sequence for bioeroding polymers is best described by which of the following? a) hydrophobic bulk erosion b) hydrophilic bulk erosion c) hydrolysis of PLGA d) surface erosion e) none of the above
a
toughness is one property of metals that makes them useful for many biomedical applications. Toughness can be considered a combination of a) strength and ductility/ultimate elongation b) yield strength and ultimate tensile strength c) elongation and wear d) resilience and hardness e) Young's Modulus and Yield Strength
b
very fine grained polycrystalline bioceramics can be made by heating and compressing and then used for load bearing orthopedic joints. Which statement best describes these materials? a) strong and sticky b) smooth and hard c) porous and flexible d) hard and ductile e) none of these
1. biomaterial-blood interactions 2. biomaterial-tissue interactions
what are the two broad categories of material interactions affected by protein adsorption
b
what does it mean to tailor biodegradation in a biomaterial? a) use Tailor's Theorem to calculate the rate b) design the rate of the degradation of a material on purpose c) expand the material to fit the physical constraints d) finding different materials for different bioactive functions
a
what is a fluorinated biomaterial? a) a polymer with repeat unit containing C-F bonds yielding many unique chemical and physical properties that give rise to several biomedical applications b) biomaterial polymer containing both silica and fluorine c) linear chain C-F polymer biomaterial with low molecular weight and poor lubricity d) generally hard, highly-crosslinked thermoset C-F polymers with little creep e) all of the above
c
what is the immediate and early response to injury and of relatively short duration? a) fibrous capsule development b) provisional matric formation c) acute inflammation d) chromic inflammation e) anastomotic hyperplasia
c
what is the maximum number of pathogens to meet regulatory standards for sterility? a) 1/1000 b) 1/100 c) 1/1000000 d) 1/100000 e) 1/10000000
b
what kind of defect does the alloying do to a metal? a) volume defect b) point defect c) mass defect d) line defect
d
which is NOT a disadvantage to Nitinol? a) nickel allergies b) difficult to machine c) unwanted calcification or immunogenic response d) shapememory and super-elasticity
c
which is NOT a general advantageous property of metals? a) high strength and elastic modulus b) thermal conductivity c) low Tm d) electrical conductivity
a, b, and d
which is a true statement regarding engineered natural materials (ENM) a) ENM biomaterials can contain synthetic materials b) ENM biomaterials can be used the same function as their sources or the material can be engineered into a new function based on the properties of the material c) ENM must come from natural sources external to the human body d) ENM include commercial products such as would dressings and sutures
d
which is not one of the five core characteristics of biomaterials science? a) multidisciplinary b) clinical need-driven c) substantial world market d) fabrication e) risk-benefit analysis
d
which is not significant regarding material surface properties? a) surfaces have unique reactivity b) the surface is inevitable different from bulk c) the mass of material that makes up the surface zone is very small d) macroscopic testing methods determine mechanical behavior e) surfaces molecules can exhibit considerable mobility
c
which level of structure is most important in distinguishing the material categories metallic, ceramic, and polymer? a) macroscopic bulk properties b) synthetic purity c) chemical bonding between atoms and/or molecules d) surface properties e) length of molecular chains in materials
e
which of the following are factors that affect protein adsorption? a) blood type/composition b) surface hydrophobicity c) surface charge d) protein concentration e) all of the above
b and e
which of the following are main sources for radiation sterilization? a) ethylene oxide b) Co^60 gamma c) uranium d) alpha rays e) electron beam
a, b, c, and d
which of the following are steps towards the processing of a metal? a) mining the natural ores and metal oxides b) final cleaning and sterilizing c) fabricating into specific shapes d) surface treatments e) genetic altering
a
which of the following best describes hydrogels? a) a water insoluble 3D network of polymeric chains that are crosslinked by chemical or physical bonds b) they are used for their soft hydrophobic nature that mimics soft tissue c) they contain less than 10% water d) none of the above
b
which of the following best describes poly(methyl methacrylate) PMMA generally known as acrylic? a) it is a true silica glass b) it is amorphous and atactic c) it is a soft thermoset elastomer d) it is a highly oxygen permeable e) all of the above
d
which of the following best describes the Silly Putty? a) thermoplastic acrylic b) crosslinked fluoropolymer c) thermoset polyurethane d) viscoelastic silicone
a and d
which of the following can be considered disadvantages for cobalt-60 radiation sterilization? a) free radicals may cause crosslinking in some biomedical polymers b) it requires high temperature and steam c) radiation exposure has very limited penetration d) may not kill all microbes such as resistant viruses e) generates high amounts of ozone
d
which of the following characteristics of a property is more important in regards to biological interaction for a medical device implant? a) bulk properties b) ionic bonding forces c) microstructure and grain boundary defects d) surface properties e) stress-strain mechanical properties
d
which of the following is NOT a basis benefit of natural biomaterials? a) potentially abundant and inexpensive b) potential enhanced biocompatibility from recognition of material c) unique properties that are difficult to synthesize d) lot-to-lot consistency
e
which of the following is NOT a biomedical application for degradable or resorbable biomaterials a) orthopedic devices b) tissue engineering scaffolding c) drug delivering devices d) dissolving sutures e) hydrolytic pacemakers
b
which of the following is NOT a challenge of using hydrogels? a) mechanical strength based on degree of swelling b) soft hydrophilic nature mimics soft tissue c) difficult in handling based on strength and lubricity d) difficulty with precise drug loading and release based on swelling
b
which of the following is NOT a challenging associated with using a hydrogel? a) can be mechanically weak based on degree of swelling b) returns to its original shape when a certain temperature is reached c) difficulty in handling based on strength and lubricity d) difficulty with precise drug loading and release
d
which of the following is NOT a common method of testing blood mentioned? a) ISO 10993-4 tests b) in vivo c) ex vivo d) ex vitro e) in vitro
b
which of the following is NOT a method for improving mechanical strength for metals? a) alloying b) melting c) grain size refining d) cold working
e
which of the following is NOT a method used for sterilization? a) Co^60 radiation b) steam autoclaving c) hydrogen peroxide d) ethylene oxide e) electrophoresis
b and e
which of the following is NOT a significant metal or metal alloy used as a biomaterial? a) commercially pure titanium b) tricalcium phosphate c) 316L stainless steel d) cobalt-chromium e) alumina
b
which of the following is NOT a tissue or cellular host response to injury? a) wound healing b) blood thinning c) foreign body reaction d) inflammation e) granulation tissue
d
which of the following is NOT an area that Biomaterials Science traditionally has emphasized? a) material synthesis b) material characterization c)host-material interaction d) material history
b
which of the following is NOT an important hemocompatibility characteristic from Virchow's triad? a) blood chemistry/characteristics b) tissue encapsulation c) flow regime d) material surface characteristics e) none of the above
a
which of the following is NOT one of the four basic concepts that define biocompatibility? a) chemical effects b) toxicology c) mechanical effects d) reactions to extrinsic organisms e) cell-biomaterial interactions
d
which of the following is NOT one of the four main types of resolutions the body has a foreign body response: a) extrusion b) resorption c) integration d) intrusion e) encapsulation
b and c
which of the following is NOT true regarding alginates use as an engineered natural material? a) alginate is a polysaccharide that can be crosslinked into hydrogels b) cells adhere readily to the surfaces of engineered alginate materials c) alginates break down enzymatically because they are foreign to mammalian cells d) alginates do not break down enzymatically because they are foreign to mammalian cells e) stiffness and elasticity can be altered by a degree of crosslinking
a
which of the following is a general advantage of silicones? a) silicones have a wide temperature range stability with a very low Tg b) silicones are always hydrophilic implants and are quickly coated with proteins c) silicones are thermoplastic materials d) silicones are extremely stable in high acidity environments e) all of the above
d
which of the following is a general characteristic of ceramics compared to metals? a) high conductivity b) high ductility c) easy machining d) high brittleness d) all of the above
e
which of the following is a mechanism for physical breakdown of a biopolymer? a) cleavage of internally located covalent bonds in a polymer backbone b) breaking of crosslinking bonds between polymer chains c) side chains reactions d) breaking of end backbone linkages in a polymer backbone e) cleavage of secondary bonds in the polymer network
e
which of the following is a protein property that affects surface interactions? a) size b) charge c) hydrophobicity d) stability e) all of the above
c
which of the following is a typical disadvantage of Nitinol? a) it is difficult to sterilize b) it cannot hold its shape and is not a good material to be used in the body, especially as a stent c) machining is possible but tool wear is excessive and it must be cold processed d) it may elicit unwanted calcification or unwanted immunogenic responses
e
which of the following is an advantage of e-beam sterilization? a) generates high amounts of ozone b) generates high amounts of radioactive material c) free radicals may alter the biomaterial d) no free radicals are involved e) it can be turned on and off
d
which of the following is not considered a factor of biocompatibility? a) toxicology b) extrinsic organisms c) cell biomaterial interactions d) cost efficiency e) mechanical effects
b
which of the following is true for physical crosslinking of a hydrogel rather than chemical crosslinking a) polymer chains are covalently bonded into a 3D network b) generally weaker and with more reversible chain interactions c) typically more resistive to harsh environments d) network or disordered chains held together by associative forces such as molecular entanglements, hydrophobic interactions and hydrogen bonding
d
which of the following polyesters has the fastest hydrolysis degradation? a) 100% PLA b) 100% PGA c) 75:25 PLGA copolymer d) 50:50 PLGA copolymer e) all have the same hydrolysis rates
c
which of the following processing methods weakens a metal? a) adding planar defects to decrease the grain size b) alloying with a secondary metal casting compressive strain crystal distortion c) increasing porosity through casting voids d) introducing precipitates to add volumetric defects in a metal e) all of the above
d
which of the following statements best describes a polymer with the following composition A-B-B-A-A-A-B-A-A-B-A-A-B-A-A-A a) homopolymer b) branched homopolymer c) block copolymer d) random copolymer e) random crosslinked polymer
c
which of the following statements best describes the mechanism for killing microbes by ethylene oxide, a highly toxic cyclic ether gas used for industrial terminal sterilization? a) competitive adsorption suffocation b) hydration of DNA carboxylic acid groups c) alkylation of DNA amine groups d) DNA scission by oxidizing free radicals e) secondary electron bombardment
b and c
which of the following statements is true about the field of biomaterials? a) the modern field of biomaterials started in the 1980s b) some crude biomaterials have been successfully used in history in various ways c) biomaterials science is a convergence that integrates the basic sciences of material science, biology, chemistry, and physics d) the field of biomaterials is a narrow field with exact definitions of a biomaterial e) a biomaterial is successful only if its use in the body enhances the biological function beyond its natural function
d
which of these is NOT a general problem with hydrogels? a) they are mechanically weak based on a degree of swelling b) they are difficult to sterilize c) it is hard for exact drug loading d) they return to their original shape when a certain temperature is reached
a
which property would NOT be desired for a metal used to make the ball section of a hip joint? a) high ductility (indicates plastic deformation rather than high strength) b) high compressive strength c) low friction d) long wear life d) none of the above
a
why are the crystalline structures important for giving the bulk properties and function of a metal? a) it provides a basis for understanding how the atomic structures react to the material stresses b) because there are very few regions c) because the point defects in metals include vacancies d) the crystalline regions only form 2D structures
c
why is fatigue testing important? a) to calculate glass transition temperatures b) to determine heat and rate c) to determine the lifetime of a material d) to determine how a liquid behaves e) to determine surface wettability