Reaching a Vapor Sensitivity of 0.01 Parts Per Quadrillion in the Screening of Large Volume Freight

The feasibility of detecting explosives in the atmosphere at concentrations as low as 0.01 ppq hinges on the poorly known question of what interfering species exist at these or higher concentrations. To clarify the issue, hundreds of samples of ambient air, either clean or <i>loaded</i> with explosives (from lightly contaminated environments) have been collected in fiberglass/stainless steel filters coated with Tenax-GR, thermally desorbed at variable temperature, and ionized with Cl^– via secondary electrospray (SESI). They are analyzed with a narrow-band mobility filter (SEADM’s P5 DMA) and a triple quadrupole mass spectrometer (Sciex’s 5500), configured in series to transmit precursor and fragment ions of the explosives Nitroglycerin, PETN, RDX, and TNT. Blanks were sampled outdoors at a rural site (Boecillo, Valladolid, Spain), and <i>loads</i> were sampled at diverse locations. For RDX and TNT, atmospheric background inhibits detection below 1 part/trillion (ppt) without mobility filtering. This interference was drastically reduced by the DMA, allowing detection up to 1 part/quadrillion (ppq). Further sensitivity increase was achieved by scanning over a mobility region several percent around that of the target explosive, to separate various isobaric compounds by Gaussian deconvolution. (i) All four MS/MS channels analyzed exhibit several background peaks within the narrow mobility intervals investigated. At least one of these interferents is much stronger than the instrument background at the explosive’s mobility, making DMA separation most helpful. (ii) For Nitroglycerin and PETN the combined filtering techniques have not lowered ambient chemical noise down to 0.01 ppq. (iii) Interferents are greatly reduced for TNT and RDX, resulting in minimal chemical noise: 322 blank tests for RDX yielded <i>mean</i> signal of 0.0012 ppq and standard deviation σ = 0.0035 ppq (<i>mean + 3σ</i> detection limit of 0.01 ppq)

Diet-Induced Changes in n-3- and n-6-Derived Endocannabinoids and Reductions in Headache Pain and Psychological Distress.

Omega-3 and omega-6 fatty acids are biosynthetic precursors of endocannabinoids with antinociceptive, anxiolytic, and neurogenic properties. We recently reported that targeted dietary manipulation-increasing omega-3 fatty acids while reducing omega-6 linoleic acid (the H3-L6 intervention)-reduced headache pain and psychological distress among chronic headache patients. It is not yet known whether these clinical improvements were due to changes in endocannabinoids and related mediators derived from omega-3 and omega-6 fatty acids. We therefore used data from this trial (N = 55) to investigate 1) whether the H3-L6 intervention altered omega-3- and omega-6-derived endocannabinoids in plasma and 2) whether diet-induced changes in these bioactive lipids were associated with clinical improvements. The H3-L6 intervention significantly increased the omega-3 docosahexaenoic acid derivatives 2-docosahexaenoylglycerol (+65%, P < .001) and docosahexaenoylethanolamine (+99%, P < .001) and reduced the omega-6 arachidonic acid derivative 2-arachidonoylglycerol (-25%, P = .001). Diet-induced changes in these endocannabinoid derivatives of omega-3 docosahexaenoic acid, but not omega-6 arachidonic acid, correlated with reductions in physical pain and psychological distress. These findings demonstrate that targeted dietary manipulation can alter endocannabinoids derived from omega-3 and omega-6 fatty acids in humans and suggest that 2-docosahexaenoylglycerol and docosahexaenoylethanolamine could have physical and/or psychological pain modulating properties. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01157208) PERSPECTIVE: This article demonstrates that targeted dietary manipulation can alter endocannabinoids derived from omega-3 and omega-6 fatty acids and that these changes are related to reductions in headache pain and psychological distress. These findings suggest that dietary interventions could provide an effective, complementary approach for managing chronic pain and related condition