Spitzer-MIPS survey of the young stellar content in the Vela Molecular Cloud-D

A new, unbiased Spitzer-MIPS imaging survey (~1.8 square degs) of the young stellar content of the Vela Molecular Cloud-D is presented. The survey is complete down to 5mJy and 250mJy at 24micron (mu) and 70mu, respectively. 849 sources are detected at 24mu and 52 of them also have a 70mu counterpart. The VMR-D region is one that we have already partially mapped in dust and gas millimeter emission, and we discuss the correlation between the Spitzer compact sources and the mm contours. About half of the 24mu sources are located inside the region delimited by the 12CO(1-0) contours (corresponding to only one third of the full area mapped with MIPS) with a consequent density increase of about 100% of the 24mu sources [four times for 70mu ones] moving from outside to inside the CO contours. About 400 sources have a 2MASS counterpart. So we have constructed a Ks vs. Ks-[24] diagram and identified the protostellar population. We find an excess of Class I sources in VMR-D in comparison with other star forming regions. This result is reasonably biased by the sensitivity limits, or, alternatively, may reflect a very short lifetime (<=10^6yr) of the protostellar content in this cloud. The MIPS images have identified embedded cool objects in most of the previously identified starless cores; in addition, there are 6 very young, possibly Class 0 objects identified. Finally we report finding of the driving sources for a set of five out of six very compact protostellar jets previously discovered in near-infrared images.Comment: 29 pages, 14 figures. To appear in Ap.

Structural Variations in the Complete Series of Lanthanoid Complexes of a Calix[4]arene Trisamide

Lanthanoid picrate (pic) complexes of 5,11,17,23-tetra-tert-butyl-25-hydroxy-26,27,28-tris(diethylcarbamoylmethoxy)calix[4]arene (LH) have been synthesised and structurally characterised, to complete this series for all lanthanoids (other than promethium). From cerium to lutetium, three structural types are observed: Type I, [Ln(L)(O,O'-pic)](pic), Ln = Ce-Dy; Type II, [Ln(L)(O-pic)](pic), Ln = Tb, Ho; Type III, [Ln(L)(HOEt)](pic)2, Ln = Er-Lu. With lanthanum, three different ten-coordinate complexes were characterised; [Ln(L)(O,O'-pic)(HOEt)](pic), [Ln(L)(O,O'-pic)(OH2)](pic), and [Ln(L)(O,O'-pic)(HOMe)](pic). The crystallisation of Type I and II observed for terbium shows that the stability of the different structures are sensitively poised at the transition points. Nevertheless, the structures show that the vacant space in the coordination sphere left by the trisamide L tends to reduce across the series as expected. It is occupied by a bidentate picrate anion and unidentate solvent molecule with lanthanum, a bidentate picrate anion for cerium to dysprosium (Type I), a unidentate picrate anion for terbium and holmium (Type II), and finally a unidentate solvent molecule from erbium to lutetium (Type III). The coordination number thus reduces from 10 to 8 across the series

Microencapsulated sorbic acid and nature-identical compounds reduced Salmonella Hadar and Salmonella Enteritidis colonization in experimentally infected chickens

ABSTRACT The reduction of Salmonella prevalence in broilers is a priority in European Union agricultural policies because treatment with antibiotics is forbidden by Regulation (EC) 2160/2003. Two trials were conducted to evaluate the efficacy of a microencapsulated blend of sorbic acid and nature-identical compounds (i.e., chemically synthesized botanicals; SAB) on the reduction of the cecal prevalence and contents of Salmonella enterica serovars Hadar and Enteritidis in experimentally infected chickens. In the first trial, 125 one-day-old Lohmann specific-pathogen-free chickens were assigned to one of the following treatments: negative control (not challenged and not treated), positive control (challenged and not treated), SAB0.3, SAB1, or SAB5 (challenged and treated with the microencapsulated blend included in the feed at 0.03, 0.1, or 0.5%, respectively). At 30 d of age, birds were infected with 106 cfu of Salmonella Hadar, and after 5, 10, or 20 d postinfection, 5, 10, and 10 birds per treatment, respectively, were killed and the cecal contents and liver and spleen samples were analyzed for Salmonella Hadar. In the second trial, 100 one-day-old Ross 708 chickens were assigned to 1 of 5 treatments: control (not treated), SAB0.3, SAB1, SAB2, or SAB5 (treated with the blend included in the feed at 0.03, 0.1, 0.2, or 0.5%, respectively). At 7 d of age, the birds were challenged with 105 cfu of Salmonella Enteritidis, and after 7, 14, or 24 d after challenge, 5, 5, and 10 birds per treatment, respectively, were killed and cecal contents were analyzed for Salmonella Enteritidis. Results showed that in the early stage of infection Salmonella prevalence was high in both studies, whereas at the end of the observation periods, the blends at 0.03, 0.1, and 0.5 in the challenge with Salmonella Hadar and at 0.2 and 0.5% in the challenge with Salmonella Enteritidis significantly reduced (by 2 log10 cfu) the cecal content of Salmonella. This study showed that intestinal delivery of microencapsulated sorbic acid and nature-identical compounds can result in a 100-fold reduction of Salmonella at the intestinal level in broilers at slaughter age

The 2008 outburst in the young stellar system ZCMa: I. Evidence of an enhanced bipolar wind on the AU-scale

Accretion is a fundamental process in star formation. Although the time evolution of accretion remains a matter of debate, observations and modelling studies suggest that episodic outbursts of strong accretion may dominate the formation of the protostar. Observing young stellar objects during these elevated accretion states is crucial to understanding the origin of unsteady accretion. ZCMa is a pre-main-sequence binary system composed of an embedded Herbig Be star, undergoing photometric outbursts, and a FU Orionis star. The Herbig Be component recently underwent its largest optical photometric outburst detected so far. We aim to constrain the origin of this outburst by studying the emission region of the HI Brackett gamma line, a powerful tracer of accretion/ejection processes on the AU-scale in young stars. Using the AMBER/VLTI instrument at spectral resolutions of 1500 and 12 000, we performed spatially and spectrally resolved interferometric observations of the hot gas emitting across the Brackett gamma emission line, during and after the outburst. From the visibilities and differential phases, we derive characteristic sizes for the Brackett gamma emission and spectro-astrometric measurements across the line, with respect to the continuum. We find that the line profile, the astrometric signal, and the visibilities are inconsistent with the signature of either a Keplerian disk or infall of matter. They are, instead, evidence of a bipolar wind, maybe partly seen through a disk hole inside the dust sublimation radius. The disappearance of the Brackett gamma emission line after the outburst suggests that the outburst is related to a period of strong mass loss rather than a change of the extinction along the line of sight. Based on these conclusions, we speculate that the origin of the outburst is an event of enhanced mass accretion, similar to those occuring in EX Ors and FU Ors.Comment: Accepted for publication in Astronomy and Astrophysics Letter

One-step assembly of Re(I) tricarbonyl 2-pyridyltetrazolato metallacalix[3]arene with aqua emission and reversible three-electron oxidation

The reaction of 2-pyridyltetrazolate with [Re(CO)5X] (X = Cl, Br) yielded the formation of an unexpected cyclic metallacalix[3]-arene, as revealed by X-ray structural studies, characterised by aqua emission and reversible three-electron oxidation

A Fluorine-18 Radiolabeling Method Enabled by Rhenium(I) Complexation Circumvents the Requirement of Anhydrous Conditions

Azeotropic distillation is typically required to achieve fluorine-18 radiolabeling during the production of positron emission tomography (PET) imaging agents. However, this time-consuming process also limits fluorine-18 incorporation, due to radioactive decay of the isotope and its adsorption to the drying vessel. In addressing these limitations, the fluorine-18 radiolabeling of one model rhenium(I) complex is reported here, which is significantly improved under conditions that do not require azeotropic drying. This work could open a route towards the investigation of a simplified metal-mediated late-stage radiofluorination method, which would expand upon the accessibility of new PET and PET-optical probes

The status of PD-L1 and tumor-infiltrating immune cells predict resistance and poor prognosis in BRAFi-treated melanoma patients harboring mutant BRAFV600

In the present study, we have provided clinical evidence of the predictive and prognostic relevance of tumoral PD-L1 expression and density of immune cell infiltration in BRAFV600-mutated metastatic melanoma patients treated with BRAF inhibitor