Ultrasound guided greater occipital nerve blocks for post-traumatic occipital neuralgia.

Chronic headaches can be debilitating for many patients. They often have a nebulous etiology, unpredictable course, and can be difficult to manage. We describe a post-traumatic headache that began after a motor vehicle collision. The patient sustained multiple injuries including a scalp laceration and bilateral occipital condyle fractures. Oral agents were unable to quell this patient's headaches. The diagnosis of occipital neuralgia was suspected based on history and presentation. Our patient received dramatic relief after ultrasound guided bilateral greater occipital nerve blocks.

Determination of the nature of naphthenic acids present in crude oils using nanospray Fourier transform ion cyclotron resonance mass spectrometry: the continued battle against corrosion.

Recent research has shown that the corrosivity of naphthenic acids is related to their molecular mass and that the "total acid number" (TAN), traditionally used as an indicator of the naphthenic acid content of an oil, is not as reliable as first believed. The presence of naphthenic acids in crude oils leads to the corrosion of oil refinery equipment, with the oil industry incurring costs that will ultimately be passed on to the consumer. With regard to these concerns, mass spectrometry has been increasingly applied to the investigation of the naphthenic acid content of crude oils. To ascertain the nature of the species present, however, it is necessary to utilize an ionization technique that does not result in fragmentation, ensuring the detection only of molecular species which provide useful information about the sample constitution. In the following investigation, negative ion mode nanospray Fourier transform ion cyclotron resonance (FTICR) mass spectrometry has been applied to the analysis of crude oil samples, providing insight into the different acidic species that were present. Use of the negative ion mode to allow the selective observation of the naphthenic acids and the inherent high mass accuracy and ultrahigh resolution of FTICR mass spectrometry ensure that this technique is very well suited to the characterization of naphthenic acids within a crude oil sample. Determination of the nature of the naphthenic acids present provides vital information, such as the acids' sizes and composition, which may be used in the battle against corrosion and also used to fingerprint samples from different oil fields.