Direct tracking of H2 roaming reaction in real time.

Roaming is an unconventional type of molecular reaction where fragments, instead of immediately dissociating, remain weakly bound due to long-range Coulombic interactions. Due to its prevalence and ability to form new molecular compounds, roaming is fundamental to photochemical reactions in small molecules. However, the neutral character of the roaming fragment and its indeterminate trajectory make it difficult to identify experimentally. Here, we introduce an approach to image roaming, utilizing intense, femtosecond IR radiation combined with Coulomb explosion imaging to directly reconstruct the momentum vector of the neutral roaming H2, a precursor to H 3 + formation, in acetonitrile, CH3CN. This technique provides a kinematically complete picture of the underlying molecular dynamics and yields an unambiguous experimental signature of roaming. We corroborate these findings with quantum chemistry calculations, resolving this unique dissociative process.

Broadband infrared confocal imaging for applications in additive manufacturing.

We address new measurement challenges relating to 3D printing in metal powder using the powder bed fusion technique. Using a combination of confocal microscopy principles and fast, sensitive mid-infrared collection techniques, we present a compact and versatile method of measuring and analyzing broadband thermal emissions from the vicinity of the molten metal pool during the additive manufacturing process. We demonstrate the benefits of this instrumentation and potential for scientific research as well as in situ monitoring. Our compact microscope collection optics can be implemented in various powder bed fusion machines under vacuum or inert atmospheric environments to enable extensions such as multi-color pyrometry or spectroscopic studies of additive manufacturing processes.

A comparison of medication side effect reports by panic disorder patients with and without concomitant cognitive behavior therapy.

OBJECTIVE: The authors assessed whether adding cognitive behavior therapy (CBT) to imipramine for patients with panic disorder decreased the severity of side effects and dropouts from side effects. METHOD: Data were analyzed for 172 panic disorder patients who were randomly assigned to receive imipramine alone, imipramine plus CBT, or placebo. Mixed-effects models were used to assess longitudinal differences among the treatment groups with respect to side effect burden and dropout rates during the acute, maintenance, and follow-up phases of treatment. RESULTS: Patients treated with imipramine plus CBT experienced less severe fatigue/weakness, dry mouth, and sweating and had a lower rate of dropout due to side effects compared with those treated with imipramine only. CONCLUSIONS: The addition of CBT to medication treatment with imipramine was associated with less severe side effects and fewer dropouts due to perceived side effects than treatment with imipramine alone.