Spectral and Thermal Studies of Light Lanthanide Complexes with 4-Methoxy-3-nitrobenzoic Acid

4-Methoxy-3-nitrobenzoates of light lanthanides with a metal to ligand ratio of 1:3 have been obtained as hydrated salts. They have colours typical of Ln3+ ions (Pr-green, Nd-pink, Sm-cream, and La, Ce, Eu and Gd-white). The carboxylate group appears to be a bidentate chelating ligand. 4-Methoxy-3-nitrobenzoates of light lanthanides are crystalline compounds. During heating in air, they decompose explosively. Therefore, their thermal stability was studied in the temperature range 273–523 K. The complexes dehydrate in one or three steps. The solubilities of complexes were measured in water at 293 K. They are in the order of 10–4 mol dm–3

Variable stars in the field of the old open cluster NGC 2243

We report results of photometric monitoring of the NGC 2243 field in V and $I$ filters. Two W~UMa-type systems and three detached eclipsing binaries were discovered. Both contact systems are likely members of the cluster. One of detached binaries - variable V1 - has a period P=1.188 day. This variable is located at the cluster's turnoff in the color-magnitude diagram. Determination of parameters for components of V1 can provide direct information about properties of turnoff stars in NGC 2243 as well as to allow direct determination of cluster's distance. A background RR Lyr variable was found in the monitored field. The reddening of NGC 2243 is estimated at E(V-I)=0.10\pm 0.04 based on the V-I color exhibited by this star at minimum light. The observed distribution of colors for the background halo stars shows a cutoff at (V-I)\approx 0.60 what implies $E(V-I)\leq 0.12$ for the cluster.Comment: 18 pages, uuencoded postscript, includes 9 figures. Submitted to A&

Spectral and Thermal Studies of Light Lanthanide Complexes with 4-Methoxy-3-nitrobenzoic Acid

4-Methoxy-3-nitrobenzoates of light lanthanides with a metal to ligand ratio of 1:3 have been obtained as hydrated salts. They have colours typical of Ln3+ ions (Pr-green, Nd-pink, Sm-cream, and La, Ce, Eu and Gd-white). The carboxylate group appears to be a bidentate chelating ligand. 4-Methoxy-3-nitrobenzoates of light lanthanides are crystalline compounds. During heating in air, they decompose explosively. Therefore, their thermal stability was studied in the temperature range 273–523 K. The complexes dehydrate in one or three steps. The solubilities of complexes were measured in water at 293 K. They are in the order of 10–4 mol dm–3

A Case of Extensive Infl ammatory Changes (Osteomyelitis) in an Infant’s Skeleton from the Medieval Burial Ground (11th–12th c) in Wawrzeńczyce (Near Krakow)

The aim of this study was to diagnose and describe extensive infl ammatory changes in a child’s skeleton from Wawrzeńczyce, (the medieval period). The aim of the analysis was to determine the nature of the infl ammatory changes and their etiology by means of macroscopic techniques as well as X-ray analysis. The tests revealed that the individual suffered from a hematogenous multifocal osteitis. This condition might have been a result of an acute or sub-acute osteitis, and the untreated form of osteomyelitis might have contributed to the infection of the entire developing organism, leading to death

Test measurements of thoron concentration using two ionization chambers AlphaGUARD vs. radon monitor RAD7

The experiment aiming at testing the possibility of using AlphaGUARD monitors based on an ionization chamber for thoron measurements is presented. A single AlphaGUARD monitor working in the flow mode was applied to measure thoron concentration in the radon-free atmosphere. The sensitivity (correction factors) of the monitor to thoron was estimated by comparison with a RAD7 portable detector (Durridge Company), based on spectrometric analysis, in the thoron, radon-free atmosphere in a calibration chamber. This depends on the applied flow rate and changes from 8% for the flow rate of 0.3 dm3/min to 36% for 1 dm3/min. It was also revealed that the sensitivity of the monitor to thoron in the diffusion mode is equal to ca. 5% and may be neglected. The method involving two Alpha-GUARD monitors working in two different modes (diffusion and flow) at the same time may be used to evaluate radon and thoron concentration in the natural environmental conditions where usually both isotopes appear together. In this method thoron concentration is estimated as the difference of results obtained from two AlphaGUARD monitors multiplied by the correction factor corresponding to the applied flow rate. The devices based on spectrometric analysis, e.g. RAD7 seem to be a better tool for thoron measurements in the environmental conditions

Investigation of the influence of chamber construction parameters on radon exhalation rate

Radon exhalation from ground is a process dependent on the emanation and migration of radon through ambient air. Most studies on radon exhalation from soil were performed regarding the influence of meteorological and soil parameters. As radon exhalation rate can be affected by the internal properties of the sample, it may also be influenced by the exhalation chamber geometry such as volume-to-area (V/S) ratio or other construction parameters. The measurements of radon exhalation from soil were made using different constructions of accumulation chamber and two types of radon monitors: RAD7 (Durridge) and AlphaGUARD PQ2000PRO (Genitron). The measurements were performed on one site in two locations and approximately at the same time. The first tests did not show the correlations of exhalation rate values and the chamber's construction parameters and their geometrical dimensions. However, when examining the results, it seems that there are still too many factors that might have affected the process of radon exhalation. The future experiments are planned to be conducted in controlled laboratory conditions