Search results for "X-Ray"

YSOs in DROXO (Deep rho Oph XMM obs.)

2011

X-rays from very young stars are powerful probes to investigate the mechanisms at work in the very first stages of the star formation and the origin of X-ray emission in very young stars. We present results from a 500ks long observation of the rho Ophiuchi cloud with a XMM-Newton large program named DROXO, aiming at studying the X-ray emission of deeply embedded young stellar objects (YSOs). Cone search capability for table J/A+A/519/A34/tablea1 (List of sources detected in the DROXO EPIC images) Cone search capability for table J/A+A/519/A34/tablea3 (ISOCAM YSOs (Bontemps et al. 2001, J/A+A/372/173) undetected in the DROXO field of view)

Chandra X-ray observation of Gum 31

2014

Gum 31 is a prominent, but still rather poorly studied HII region around the stellar cluster NGC 3324 at the northwestern periphery of the Carina nebula complex. Our aim was to reveal and characterize the young stellar population in Gum 31. An X-ray survey is the only efficient way to identify young stars in this region with extremely high galactic field-star contamination that can avoid the strong biases of infrared excess selected samples of disk-bearing young stars. We used the Chandra observatory to perform a deep (70ks) X-ray observation of the Gum 31 region and detected 679 X-ray point sources. This extends and complements the X-ray survey of the central Carina nebula regions performe…

XMM Optical Monitor Survey of TMC

2007

The Optical Monitor (OM) on-board XMM-Newton obtained optical/ultraviolet data for the XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST), simultaneously with the X-ray detectors. With the XEST OM data, we study the optical and ultraviolet properties of TMC members, and to perform correlative studies between the X-ray and OM light curves. In particular, we aim to determine whether accretion plays a significant role in the optical/ultraviolet and X-ray emissions. The Neupert effect in stellar flares is also investigated. Coordinates, average count rates and magnitudes were extracted from OM images, together with light curves with low time resolution (a few kiloseconds). For a fe…

DOSY NMR, X-ray Structural and Ion-Mobility Mass Spectrometric Studies on Electron-Deficient and Electron-Rich M6L4 Coordination Cages.

2015

A novel modular approach to electron-deficient and electron-rich M6L4 cages is presented. From the same starting compound, via a minor modulation of the synthesis route, two C3-symmetric ligands L1 and L2 with different electronic properties are obtained in good yield. The trifluoro-triethynylbenzene-based ligand L1 is more electron-deficient than the well-known 2,4,6-tri(4-pyridyl)-1,3,5-triazine, while the trimethoxy-triethynylbenzene-based ligand L2 is more electron-rich than the corresponding benzene analogue. Complexation of the ligands with cis-protected square-planar [(dppp)Pt(OTf)2] or [(dppp)Pd(OTf)2] corner-complexes yields two electron-deficient (1a and 1b) and two electron-rich …

Ion pair recognition by ditopic crown ether based bis-urea and uranyl salophen receptors

2016

Eco-friendly cavity-containing iron oxides prepared by mild routes as very efficient catalysts for the total oxidation of VOCs

2018

Iron oxides (FeOx) are non-toxic, non-expensive and environmentally friendly compounds, which makes them good candidates for many industrial applications, among them catalysis. In the present article five catalysts based on FeOx were synthesized by mild routes: hydrothermal in subcritical and supercritical conditions (Fe-HT, Few200, Few450) and solvothermal (Fe-ST1 and Fe-ST2). The catalytic activity of these catalysts was studied for the total oxidation of toluene using very demanding conditions with high space velocities and including water and CO2 in the feed. The samples were characterized by X-ray diffraction (XRD), scanning and high-resolution transmission electron microscopy (SEM and…

Thiourea Based Tritopic Halogen Bonding Acceptors

2023

Series of thiourea based tritopic receptor molecules were synthesized to be used as building blocks for halogen-bonded assemblies. Here 16 new receptor molecules were synthesized from two different 2,4,6-trialkyl-1,3,5-tris(bromomethyl)benzene starting materials via tris(isothiocyanatomethyl)benzene intermediates. The alkyl substituents in the benzene ring showed to be important for isothiocyanate group formation instead of competing thiocyanate group. The synthesis route allowed us to synthesize the isothiocyanate intermediates and further the receptor molecules without typically used and highly toxic thiophosgene. Synthesized receptor molecules were used to study their halogen bond accept…

Local Structure Studies of Ti for SrTi16O3 and SrTi18O3 by Advanced X-ray Absorption Spectroscopy Data Analysis

2015

Strontium titanate is a model quantum paraelectric in which in the region of dominating quantum statistics the ferroelectric instability is inhibited due to nearly complete compensation of the harmonic contribution into ferroelectric soft mode frequency by the zero-point motion contribution. The enhancement of atomic masses by the substitution of 18O for 16O decreases the zero-point atomic motion and low-T ferroelectricity in SrTi18O3 is realized. In this study we report on the local structure of Ti in SrTi16O3 and SrTi18O3 by Ti K-edge extended x-ray absorption fine structure measurements in temperature range 6 – 300 K.

Crystallization and preliminary crystallographic analysis of the major capsid proteins VP16 and VP17 of bacteriophage P23-77.

2012

The major capsid proteins VP16 and VP17 of bacteriophage P23-77 have been crystallized using both recombinant and purified virus and preliminary diffraction analyses have been performed.

Synthesis of a Novel Hydrazone of Thieno[2,3-d]pyrimidine Clubbed with Ninhydrin: X-ray Crystal Structure and Computational Investigations

2023

The novel hydrazone-containing thieno[2,3-d]pyrimidine, namely, N′-(1,3-dioxo-1,3-dihydro-2H-inden-2-ylidene)-2-(4-oxo-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-3(4H)-yl)acetohydrazide 4 was synthesized in a very good yield from the reaction of the triketoester 1 or ninhydrin 2 with the exocyclic acetohydrazide 3 in methanol. Good-quality crystals of 4 were obtained by recrystallization of the compound from the DMF/MeOH solvent mixture. The target product 4 crystallized in the triclinic crystal system and P-1 space group. The topology analysis of molecular packing indicated that the H…H (30.4%), O…H (22.0%) and H…C (17.0%) contacts are the most dominant i…