(C) 2011 American Institute of Physics. [doi:10.1063/1.3651392]“
“It is common for crude oil from wells to be accompanied by gas and water because of the presence Birinapant of natural surfactants in the oil that stabilize the associated water. This causes foaming during processing in gas/oil separators because of the constant agitation and shear forces, which reduce the efficiency of the process and require chemical control by the addition of defoaming additives, or antifoams. In this work, we evaluated the chemical and physicochemical properties of commercial antifoam products based on silicone polyethers along with their efficiency
in inhibiting foaming and water/oil (W/O) phase separation. The commercial surfactants were characterized by NMR spectroscopy, size exclusion chromatography, determination of solubility in different solvents, and measurement of the surface and interfacial tensions. A method to test the formation of foam in oil was used to mimic the operating conditions in gas/oil separators. Finally, tests were performed with the addition of aliquots of the additive solutions (30% p/v) in oil to evaluate their efficiency in breaking up the foam under different conditions. The results show that the most polar additive (SL2)
was the most efficient in breaking up the foam. Additive SP1, which formed a heterogeneous phase find more in the oil, was also an efficient foam inhibitor and helped to separate these phases. The antifoam tests showed that these additives did not stabilize W/O emulsions, so they could be used in gravitational separation tanks in the field. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012″
“Illness perceptions of health care professionals selleck chemicals are likely to affect patient care. This study describes the illness perceptions of two groups of health care staff toward epilepsy and psychogenic nonepileptic seizures (PNES). Sixty-one health care professionals (30 emergency care [EC] and 31 neuroscience ward [NW] staff) who regularly see patients with seizures completed the adapted Illness Perception Questionnaire Revised (IPQ-R) and the Symptom Attribution Question
for epilepsy and PNES. Respondents reported a poorer understanding of PNES than of epilepsy (P<0.001), thought epilepsy was a more chronic condition (P=0.001/P<0.001) and that patients with PNES had more “”personal control”" of their seizures (P=0.014/P<0.001). Staff from both departments identified psychological causes as most important for PNES (P<0.001). EC staff also attributed PNES to behavioral issues or alcohol. The Illness Perception Questionnaire Revised and Symptom Attribution Question demonstrated important differences in attitudes of health care staff toward epilepsy and PNES. The findings illustrate why some patients with PNES have traumatic encounters with health care professionals. (C) 2011 Elsevier Inc. All rights reserved.