Psychology has recently identified itself as a health care profession and codified this change in the bylaws of the American Psychological Association. Although psychologists make a number of contributions to the nation's health--and mental health--the most identifiable activity focuses on treating physical or psychological pathology with psychological interventions. Recently, health care polic...

In simple terms, the wood cell wall is a composite made of a rigid cellulose polymer in a matrix of lignin and the hemicelluloses. The lignin polymer in the middle lamella and S2 layer is thermoplastic; that is, it softens upon heating. The glass transition temperature Tg of the lignin in the matrix is approximately 170°C (338°F). Above the matrix Tg, it is possible to cause the lignin to under...