Solved

Passage Bone Growth and Remodeling During Fracture Healing Are Often Slow

Question 57

Multiple Choice

Passage
Bone growth and remodeling during fracture healing are often slow and have potentially poor outcomes, including malunion or nonunion at the fracture site.  Magnesium bone implants can aid in bone formation and safely biodegrade in the body according to the following reaction:Mg(s) + 2H2O(l) → Mg(OH) 2(s) + H2(g) Reaction 1  Corrosion of magnesium metal in aqueous mediumHowever, magnesium metal tends to degrade too quickly and forms hydrogen gas pockets in the body.  Corrosion is slowed as the metal naturally forms a protective layer of magnesium hydroxide in a process called passivation.  Magnesium hydroxide is less soluble than magnesium metal, and its dissolution is described by the endothermic reaction:
Passage Bone growth and remodeling during fracture healing are often slow and have potentially poor outcomes, including malunion or nonunion at the fracture site.  Magnesium bone implants can aid in bone formation and safely biodegrade in the body according to the following reaction:Mg(s) + 2H<sub>2</sub>O(l) → Mg(OH) <sub>2</sub>(s) + H<sub>2</sub>(g) <strong>Reaction 1</strong>  Corrosion of magnesium metal in aqueous mediumHowever, magnesium metal tends to degrade too quickly and forms hydrogen gas pockets in the body.  Corrosion is slowed as the metal naturally forms a protective layer of magnesium hydroxide in a process called passivation.  Magnesium hydroxide is less soluble than magnesium metal, and its dissolution is described by the endothermic reaction: <strong>Reaction 2</strong>  Solubility equilibrium of Mg(OH) <sub>2</sub> in water at 25°CAlthough passivation slows down the corrosion rate, it must be slowed even further to adequately facilitate bone reformation.Researchers are interested in the differences in the corrosion rates of magnesium metal protected by different biocompatible coatings.  They compared 10-mm magnesium disks coated with compounds of various cation and anion combinations, with solubility results shown in Table 1.  The coated disks were immersed in simulated body fluid (SBF) at room temperature for 50 hours.<strong>Table 1</strong>  Solubility for Biocompatible Inorganic Salts Given in mmol/100mL of Pure Water at 25°C Adapted from Huan ZG, Leeflang MA, Zhou J, Fratila-apachitei LE, Duszczyk J. In vitro degradation behavior and cytocompatibility of Mg-Zn-Zr alloys. J Mater Sci Mater Med. 2010;21(9) :2623-35. -Throughout the experiment, researchers monitored the amount of magnesium that dissolved at various time points.  Which of the following is NOT a valid test for the rate of magnesium corrosion? A) Periodically measure the volume of H<sub>2</sub> gas evolved from the reaction. B) Periodically measure the mass of the magnesium disks. C) Periodically measure Mg<sup>2+</sup> concentration in the SBF using elemental analysis techniques. D) Periodically measure the amount of OH<sup>−</sup> produced by titrating the beaker contents with HCl. Reaction 2  Solubility equilibrium of Mg(OH) 2 in water at 25°CAlthough passivation slows down the corrosion rate, it must be slowed even further to adequately facilitate bone reformation.Researchers are interested in the differences in the corrosion rates of magnesium metal protected by different biocompatible coatings.  They compared 10-mm magnesium disks coated with compounds of various cation and anion combinations, with solubility results shown in Table 1.  The coated disks were immersed in simulated body fluid (SBF) at room temperature for 50 hours.Table 1  Solubility for Biocompatible Inorganic Salts Given in mmol/100mL of Pure Water at 25°C
Passage Bone growth and remodeling during fracture healing are often slow and have potentially poor outcomes, including malunion or nonunion at the fracture site.  Magnesium bone implants can aid in bone formation and safely biodegrade in the body according to the following reaction:Mg(s) + 2H<sub>2</sub>O(l) → Mg(OH) <sub>2</sub>(s) + H<sub>2</sub>(g) <strong>Reaction 1</strong>  Corrosion of magnesium metal in aqueous mediumHowever, magnesium metal tends to degrade too quickly and forms hydrogen gas pockets in the body.  Corrosion is slowed as the metal naturally forms a protective layer of magnesium hydroxide in a process called passivation.  Magnesium hydroxide is less soluble than magnesium metal, and its dissolution is described by the endothermic reaction: <strong>Reaction 2</strong>  Solubility equilibrium of Mg(OH) <sub>2</sub> in water at 25°CAlthough passivation slows down the corrosion rate, it must be slowed even further to adequately facilitate bone reformation.Researchers are interested in the differences in the corrosion rates of magnesium metal protected by different biocompatible coatings.  They compared 10-mm magnesium disks coated with compounds of various cation and anion combinations, with solubility results shown in Table 1.  The coated disks were immersed in simulated body fluid (SBF) at room temperature for 50 hours.<strong>Table 1</strong>  Solubility for Biocompatible Inorganic Salts Given in mmol/100mL of Pure Water at 25°C Adapted from Huan ZG, Leeflang MA, Zhou J, Fratila-apachitei LE, Duszczyk J. In vitro degradation behavior and cytocompatibility of Mg-Zn-Zr alloys. J Mater Sci Mater Med. 2010;21(9) :2623-35. -Throughout the experiment, researchers monitored the amount of magnesium that dissolved at various time points.  Which of the following is NOT a valid test for the rate of magnesium corrosion? A) Periodically measure the volume of H<sub>2</sub> gas evolved from the reaction. B) Periodically measure the mass of the magnesium disks. C) Periodically measure Mg<sup>2+</sup> concentration in the SBF using elemental analysis techniques. D) Periodically measure the amount of OH<sup>−</sup> produced by titrating the beaker contents with HCl. Adapted from Huan ZG, Leeflang MA, Zhou J, Fratila-apachitei LE, Duszczyk J. In vitro degradation behavior and cytocompatibility of Mg-Zn-Zr alloys. J Mater Sci Mater Med. 2010;21(9) :2623-35.
-Throughout the experiment, researchers monitored the amount of magnesium that dissolved at various time points.  Which of the following is NOT a valid test for the rate of magnesium corrosion?


A) Periodically measure the volume of H2 gas evolved from the reaction.
B) Periodically measure the mass of the magnesium disks.
C) Periodically measure Mg2+ concentration in the SBF using elemental analysis techniques.
D) Periodically measure the amount of OH− produced by titrating the beaker contents with HCl.

Correct Answer:

verifed

Verified

Unlock this answer now
Get Access to more Verified Answers free of charge

Related Questions

Q52: The reactivity of three oxides mixed in

Q53: Passage<br>Umami is one of five basic tastes

Q54: Which chemical properties below are those of

Q55: The conjugate acid of the dihydrogen orthosilicate

Q56: Passage<br>The alkaline-earth metals are a highly reactive

Q58: Passage<br>The radiopharmaceutical 2-deoxy-2-(<sup>18</sup>F)fluoro-D-glucose (abbreviated as <sup>18</sup>F-FDG) is

Q59: When comparing single, double, and triple covalent

Q60: Passage<br>Household cleaners commonly contain either ammonia (NH<sub>3</sub>)

Q61: Passage<br>Living organisms that require oxygen to respire

Q62: Passage<br>Within the renal system, two buffers operate