Digital gas mass flow controllers

该提案要求拨款购买气体流量控制器，这是一种可以精确调节流入实验装置的气体（氧气，二氧化碳和氮气）数量的仪器。这些控制器连接到压缩气体储罐，压缩气体储罐向控制器提供气体流入。气体的流入是根据输送到控制器的压力而不是根据气体的实际数量或体积来调节的。然后对控制器进行设置，使从控制器流出的气体按照每分钟流出的气体量严格而准确地调节。该设备将用于研究控制两栖动物呼吸的机制。两栖动物的呼吸很有趣也很重要，因为与人类和其他哺乳动物不同，两栖动物不能连续呼吸。相反，他们表现出一种不连续的呼吸模式，称为间歇性呼吸。这种类型的呼吸包括将4-8次呼吸分组为离散的发作，由称为呼吸暂停的无呼吸期分开（长度可达几分钟）。虽然间歇性呼吸在两栖动物中是正常的，但在人类中却是不正常和病态的。人类在睡眠中表现出这种呼吸模式，要么是由于气道阻塞（阻塞性睡眠呼吸暂停），要么是由于大脑中调节连续呼吸的区域异常（中枢性睡眠呼吸暂停）。人类的呼吸暂停与心脏病发作或中风等心血管疾病的风险增加有关。这项研究将检查两栖动物大脑内导致间歇性呼吸产生的机制，并可能导致对人类大脑相关呼吸疾病的深入了解。为此，我们通过实验操纵大脑不同区域的神经化学系统（通过注射各种药物），观察呼吸是如何变化的。由于不同水平的氧气和二氧化碳可以自己改变呼吸（不操纵大脑神经化学物质），所以我们必须在实验中使用气体流量控制器来控制气体水平。

This proposal is requesting funding to purchase gas flow controllers which are instruments that allow for the precise regulation of the amount of gas (oxygen, carbon dioxide and nitrogen) that flows into an experimental set-up. These controllers are connected to tanks of compressed gases which provide the controller with an inflow of gas. The inflow of gas is regulated in terms of the pressure delivered to the controller but not in terms of the actual quantity or volume of gas. The controller is then set such that the outflow of gas from the controller is tightly and accurately regulated in terms of the volume of out-flowing gas per minute. The research that this equipment will support examines mechanisms involved in controlling breathing in amphibians. Amphibian breathing is interesting and important because, unlike humans and other mammals, amphibians do not breathe continuously. Rather, they display a discontinuous pattern of breathing called episodic breathing. This type of breathing involves the grouping of 4-8 breaths into discrete episodes separated by periods of no breathing called apneas (which can be several minutes in length). While episodic breathing is normal in amphibians, it is abnormal and pathological in humans. Humans can display this pattern of breathing during sleep either due to an obstruction of the airway (obstructive sleep apnoea) or due to abnormalities in the areas of the brain that regulate continuous breathing (central sleep apnoea). Apnoea in humans is associated with increased risk for cardiovascular disease such as heart attack or stroke. This research will examine the mechanisms within the amphibian brain that lead to the production of episodic breathing and may lead to insight into brain-related breathing disorders in humans. To do this, we experimentally manipulate neurochemical systems in various regions of the brain (by injecting various drugs) and observe how breathing changes. Since different levels of oxygen and carbon dioxide can alter breathing on their own (without manipulating brain neurochemicals) it is essential that we control the gas levels in an experiment using the gas flow controllers.