Write two paper: pathology research paper on emphysema and drug effect research paper on cocaine. Each about 1000 words long, with Harvard style citations, in each should be based on three reliable and easily accessible online sources.

 All diffuse pulmonary diseases can be classified in two big categories: 1. Obstructive disease, characterized by narrowing the air paths at any level followed with increased resistance and consecutive airflow limitation; 2. Restrictive disease, characterized by decreased total lung capacity as a result of decreased expansion of lung parenchyma. [1]
The four major diffuse obstructive disorders are emphysema, chronic bronchitis, bronchiectasis, and asthma. [1, 2]
Emphysema is characterized by abnormal permanent enlargement of the airspaces distal to the terminal bronchioles, accompanied by destruction of their walls without obvious fibrosis. According to Kumar et al. emphysema is classified to its anatomic distribution within the lobule; recall that the acinus is the structure distal to terminal bronchioles, and a cluster of three to five acini is called a lobule. There are four major types of emphysema: 1. Centriacinar (centrolobular), 2. Panacinar (panlobular), 3. distal acinar (paraseptal), and 4. irregular. Centrollobular and panlobural cause clinically significant airway obstruction. Generally, in centrolobular emphysema the upper two-thirds of the lungs is more severely affected than the lower lungs, and histologically there is thinning and destruction of alveolar walls. Terminal and respiratory bronchioles may be deformed because of the loss of septa that help tether these structures in the parenchyma. With the loss of elastic tissue in the surrounding alveolar septa, there is reduced radial traction on the small airways. As a result, they tend to collapse during expiration-an important cause of chronic airflow obstruction in severe emphysema. Current opinion favors emphysema arising as a consequence of two critical imbalances: the protease-antiprotease imbalance and oxidant-antioxidant imbalance. [1, 2, 3]
All this imbalances are observed in smokers, because of the fact that smoking is considered as one of the major risk factors, besides the other, in developing emphysema. In this regard, autopsy studies have documented a much higher incidence of emphysema among cigarette smokers compared