Dynamics of cluster-forming hub-filament systems: The case of the high-mass star-forming complex Monoceros R2.

CONTEXT: High-mass stars and star clusters commonly form within hub-filament systems. Monoceros R2 (hereafter Mon R2), at a distance of 830 pc, harbors one of the closest such systems, making it an excellent target for case studies. AIMS: We investigate the morphology, stability and dynamical properties of the Mon R2 hub-filament system. METHODS: We employ observations of the 13CO and C18O 1→0 and 2→1 lines obtained with the IRAM-30m telescope. We also use H2 column density maps derived from Herschel dust emission observations. RESULTS: We identified the filamentary network in Mon R2 with the DisPerSE algorithm and characterized the individual filaments as either main (converging into the hub) or secondary (converging to a main filament) filaments. The main filaments have line masses of 30-100 M ⊙ pc-1 and show signs of fragmentation, while the secondary filaments have line masses of 12-60 M ⊙ pc-1 and show fragmentation only sporadically. In the context of Ostriker's hydrostatic filament model, the main filaments are thermally supercritical. If non-thermal motions are included, most of them are trans-critical. Most of the secondary filaments are roughly transcritical regardless of whether non-thermal motions are included or not. From the morphology and kinematics of the main filaments, we estimate a mass accretion rate of 10-4-10-3 M ⊙ yr-1 into the central hub. The secondary filaments accrete into the main filaments with a rate of 0.1-0.4×10-4 M ⊙ yr-1. The main filaments extend into the central hub. Their velocity gradients increase towards the hub, suggesting acceleration of the gas.We estimate that with the observed infall velocity, the mass-doubling time of the hub is ~ 2:5 Myr, ten times larger than the free-fall time, suggesting a dynamically old region. These timescales are comparable with the chemical age of the Hii region. Inside the hub, the main filaments show a ring- or a spiral-like morphology that exhibits rotation and infall motions. One possible explanation for the morphology is that gas is falling into the central cluster following a spiral-like pattern.

Two years' experience with inspiration breath-hold in liver SBRT.

•The workflow of inspiration breath-hold SBRT for liver metastases is described.•Inspiration breath-hold in liver SBRT is feasible for 95% of the patients.•An individual margin recipe for inspiration breath-hold liver SBRT is explained.•Margin reduction of 10 mm using inspiration breath-hold compared to free breathing.

Postmortem changes in brain catecholamine enzymes.

Postmortem changes in the activities of tyrosine hydroxylase, dopa decarboxylase, and dopamine-beta-hydroxylase were examined in various areas of rat brain. Tyrosine hydroxylase activity decreased in an exponential fashion with a half-time of two to four hours in caudate-putamen, substantia nigra, and locus ceruleus. Dopa decarboxylase activity remained within 20% of control values at five hours in these areas, but then decreased precipitously. Dopamine-beta-hydroxylase activity remained within 20% of control for at least 20 hours after death.

Modification of neutrophil functions by naftifine.

Naftifine (NF), a topical antimycotic agent, is highly active in vitro and in vivo against a wide range of pathogenic fungi. NF inhibits human polymorphonuclear leucocyte (PMN) chemotaxis. Following stimulation with zymosan-activated serum, 85-97% of the PMNs exhibited detectable membrane ruffling and polarity. In contrast, NF-treated PMNs did not exhibit such chemotactic factor-induced shape changes. We also analysed the effect of NF on PMN superoxide anion (O2-) and chemiluminescence (CL) production, as a measure of respiratory burst activity. Stimulation of PMNs pre-incubated with NF (37 degrees C for 30 min at 1-150 micrograms/ml) by FMLP, PMA and zymosan resulted in a dose-dependent inhibition in PMN CL. Doses of NF which depressed chemotaxis, inhibited CL and diminished O2- production in a statistically significant manner (P < 0.05-0.001). In conclusion, NF alters membrane-related responses in PMNs, and this alteration may be associated with a change in PMN morphology. Binding of NF to PMN membrane sterol, with a subsequent alteration in membrane configuration, is the most likely cause of the inhibition of PMN function. The data collectively document biochemical and morphological differences between control and NF-treated PMNs as determined by stimulus-specific CL and O2- generation and membrane shape change. Such differences may account, in part, for its efficacy in inflammatory fungal skin diseases.

Effect of naftifine on neutrophil adhesion.

Effective methods of fungal treatment involve reduction in fungal infections and host inflammatory responses. Naftifine (NF), a topical antifungal agent, is highly active in vitro and in vivo against a wide range of pathogenic fungi. Additionally NF has been shown to inhibit polymorphonuclear leukocyte (PMN) chemotaxis and respiratory burst activity in an irreversible dose-dependent and time-dependent manner. Since leukocyte adherence to endothelia is believed to be one of the initial crucial events in the recruitment of circulating leukocytes to the site of inflammation, we have investigated the in vitro effect of NF on PMN adherence to nylon fiber, BSA-coated glass chamber or polystyrene, and endothelial monolayers via three adherence assays. All three assays demonstrated a statistically significant reduction (p < 0.01-0.001) in PMN adherence to the respective media. In particular, NF (at 30-60 micrograms/ml) significantly inhibited PMN adherence to endothelial monolayers (p < 0.01) as measured spectrophotometrically by the uptake of rose bengal stain. Therefore, NF inhibits PMN adherence to endothelia in our in vitro model system. This inhibition may constitute part of the anti-inflammatory effect of NF.