用一段英文描述疫情下的奉献的具体事例（提及姓名）

John Smith is a nurse who works in a hospital in the city. During the coronavirus pandemic, John has been working tirelessly to ensure the safety of his patients. He has worked long hours and taken on extra shifts to make sure that everyone receives the care they need. Despite his own fatigue, John continues to show up every day with a smile on his face and determination in his heart. His dedication is an example of true selflessness and courage during these difficult times.