Pericarditis recurrence is associated with milder electrocardiographic, echocardiographic, and laboratory findings.

Recurrent pericarditis (RP) complicates approximately 30% of acute pericarditis (AP) cases. We sought to compare the prevalence and severity of objective findings seen in patients with RP. A retrospective single-center study during 2010-2019, including 765 patients diagnosed with AP. Clinical, electrocardiographic, echocardiographic, and laboratory findings were extracted from the local electronic health records. Recurrence during follow-up was documented in 134 patients (17.5%), with a median time to recurrence of 101 (± 59-251) days. The median age was 60 years (IQR 45-72), 68% were male. Most patients were defined as having idiopathic\viral pericarditis (64%). The clinical manifestation during the recurrent event of pericarditis was less prominent or attenuated when compared to the initial event-ECG signs (ST elevation 12% vs. 26%; p = 0.006, Knuckle sign 13% vs. 33%; p < 0.001, ST larger in lead L2 than L3 4% vs. 19%; p < 0.001), pericardial effusion moderate and above (11% vs. 30%; p = 0.02), and inflammatory markers (mean peak CRP levels 66 mg/l vs. 97 mg/l; p < 0.001). Similar results were seen in the subgroup of patients defined as having idiopathic\viral pericarditis. Up to 20% of patients who did not have ECG signs or a significant pericardial effusion in their 1st event demonstrated these findings during the recurrence, though still to a lesser extent compared with those who had these signs in their 1st event. The objective findings of AP are less pronounced during recurrent events. Future studies should focus on the role of advanced biomarkers and imaging in defining true RP events.

Pigtail Catheter versus Large Bore Chest Tube for the Management of Spontaneous Pneumothorax in Children: A Retrospective Study.

INTRODUCTION: Pigtail catheter (PGC) insertion due to spontaneous pneumothorax (SPT) in the pediatric population has increased markedly in the last years. However, only few studies examined its efficacy in terms of length of hospitalization, rate of complications, and especially pain management comparing to large bore catheter (LBC) insertion. We sought to compare analgetic drug consumption, efficacy, and complication rate between PGC and LBC in children with SPT. MATERIALS AND METHODS: This is a single-center retrospective study of pediatric patients that were admitted to the Schneider Children's Medical Center between 2013 and 2021 with a diagnosis of SPT. The following data were collected: type of drainage (PGC or LBC), duration of drainage, length of hospitalization, number of X-rays, complication rate, surgery during hospitalization, readmission due to SPT, and pain management. RESULTS: Seventeen PGC and 23 LBC were inserted in our study. No differences were noted in terms of hospitalization length, tube reposition or replacement, and recurrence of SPT between the groups. Patients with PGC underwent less X-rays comparing to the LBC group (3 X-rays vs. 5, median, p < 0.005). Oral analgesic use in terms of length of therapy was significantly lower in the PGC group than in the LBC group (1 vs. 3+ days, median, p < 0.05). There was no major complication in this cohort. CONCLUSION: PGC is an effective, safe, and less painful alternative compared with a LBC for the drainage of SPT in children.

Pulse propagation in the slow and stopped light regime.

Electromagnetic pulse propagation in the slow light regime and near a zero group velocity point is relevant to a plethora of potential applications, and has analogies in numerous other wave systems. Unfortunately, the standard frequency-based formulation for pulse propagation is unsuitable for describing the dynamics in such regimes, due to the divergence of the dispersion coefficients. Moreover, in the presence of absorption, it is not clear how to interpret the propagation dynamics due to the drastic change induced by absorption upon the dispersion curves. As a remedy, we present an alternative momentum-based formulation, which is rapidly converging in these regimes, and naturally suitable for lossy and nonlinear media. It is specialized to a waveguide geometry which provides a significant simplification with respect to existing momentum-based schemes. Doing so, we provide a somewhat alternative, yet intuitive picture of the seeming enhanced absorption and nonlinear response in these regimes, and show that light-matter interactions are not enhanced in the slow/stopped light regimes.

Site-dependent photodissociation of vibronically excited CD(3)NH(2) molecules.

The mechanism of H and D atom loss, following ultraviolet photolysis of methylamine-d(3), CD(3)NH(2), has been studied via electronic action and Doppler spectroscopies. The N-H bond is preferentially cleaved and the yield of both H and D photofragments increases gradually, but differently, as higher vibrational states on the first excited electronic state, A, are accessed, leading to some drop in H/D branching ratios. The average translational energies of the H photofragments are somewhat higher than those of D, implying lower energy content left in the internal degrees of freedom of the CD(3)NH than in the CD(2)NH(2) partner fragment. These results provide evidence for discrimination between the two channels and mechanistic insight into the N-H and C-D bond cleavage.

Quantum tunneling of hydrogen atom in dissociation of photoexcited methylamine.

The probability of hydrogen atom release, following photoexcitation of methylamine, CH(3)NH(2), is found to increase extensively as higher vibrational states on the first excited electronic state are accessed. This behavior is consistent with theoretical calculations, based on the probability of H atom tunneling through an energy barrier on the excited potential energy surface, implying that N-H bond breaking is dominated by quantum tunneling.

Site-dependent photodissociation of vibrationally excited CD3NH2.

The N-H and C-D bond fission in partially deuterated methylamine, CD(3)NH(2), has been investigated using vibrationally mediated photodissociation. Jet-cooled action spectra and Doppler profiles of the H and D photofragments were monitored following approximately 243.1 nm photodissociation of the parent pre-excited to two, three or four N-H stretch quanta. The action spectra were analyzed in terms of simplified local mode/normal mode (LM/NM) and NM models, allowing band assignment and determination of the strong resonances involved in the coupling. The Doppler profiles show that the released H and D photofragments have low translational energy content and that the H is the dominant product, although its yield decreases as higher pre-excited N-H vibrational states are dissociated. The dynamics of the site-dependent bond fission in CD(3)NH(2) is discussed.