The method is to extract from the crushed plant with diluted sulfuric acid, which is a stronger acid than meconic acid, but not so strong to react with alkaloid molecules. The extraction is performed in many steps (one amount of crushed plant is extracted at least six to ten times, so practically every alkaloid goes into the solution). From the solution obtained at the last extraction step, the alkaloids are precipitated by either ammonium hydroxide or sodium carbonate. The last step is purifying and separating morphine from other opium alkaloids. The somewhat similar Gregory process was developed in the United Kingdom during the Second World War, which begins with stewing the entire plant, in most cases save the roots and leaves, in plain or mildly acidified water, then proceeding through steps of concentration, extraction, and purification of alkaloids. Other methods of processing "poppy straw" (i.e., dried pods and stalks) use steam, one or more of several types of alcohol, or other organic solvents. The poppy straw methods predominate in Continental Europe and the British Commonwealth, with the latex method in most common use in India. The latex method can involve either vertical or horizontal slicing of the unripe pods with a two-to five-bladed knife with a guard developed specifically for this purpose to the depth of a fraction of a millimetre and scoring of the pods can be done up to five times.
Clinical research
Overview
Although there is ongoing clinical research examining the potential health effects of qigong, there is little financial or medical incentive to support high-quality research, and still only a limited number of studies meet accepted medical and scientific standards of randomized controlled trials (RCTs). Clinical research concerning qigong has been conducted for a wide range of medical conditions, including bone density, cardiopulmonary effects, physical function, falls and related risk factors, quality of life, immune function, inflammation, hypertension, pain, and cancer treatment. Systematic reviews
A 2009 systematic review on the effect of qigong exercises on reducing pain concluded that "the existing trial evidence is not convincing enough to suggest that internal qigong is an effective modality for pain management. "A 2010 systematic review of the effect of qigong exercises on cancer treatment concluded "the effectiveness of qigong in cancer care is not yet supported by the evidence from rigorous clinical trials." A separate systematic review that looked at the effects of qigong exercises on various physiological or psychological outcomes found that the available studies were poorly designed, with a high risk of bias in the results. Therefore, the authors concluded, "Due to limited number of RCTs in the field and methodological problems and high risk of bias in the included studies, it is still too early to reach a conclusion about the efficacy and the effectiveness of qigong exercise as a form of health practice adopted by the cancer patients during their curative, palliative, and rehabilitative phases of the cancer journey.