To make plastics, chemists and chemical engineers must do the following on an industrial scale: 1  Prepare raw materials and monomers. 2  Carry out polymerization reactions. 3  Process the polymers into final polymer resins.  Produce finished products.
Sleep apnea is a serious sleep disorder that occurs when a person's breathing is interrupted during sleep. People with untreated sleep apnea stop breathing repeatedly during their sleep, sometimes hundreds of times. This means the brain -- and the rest of the body -- may not get enough oxygen. There are two types of sleep apnea: Obstructive sleep apnea (OSA): The more common of the two forms of apnea, it is caused by a blockage of the airway, usually when the soft tissue in the back of the throat collapses during sleep.
2. Definition. Complex sleep apnea syndrome (CompSAS) is a form of sleep disordered breathing in which central apneas persist or emerge when obstructive events have disappeared with PAP therapy (see Figure 1).