Complex Formation of Alkyl-N-iminodiacetic Acids and Hard Metal Ions in Aqueous Solution and Solid State

The calcium(II), iron(III) and chromium(III) alkyl-N-iminodiacetate systems have been studied in aqueous solution with respect to stability, acid-base properties and structure. The calcium(II) ion forms only one weak complex with methyl-N-iminodiacetic acid in water,K-1 = 12.9 (2) mol(-1).dm(3), while iron(III) and chromium(III) form very stable complexes with alkyl-N-iminodiacetic acids. The calcium(II)-methyl-N-iminodiacetate complex is octahedral in the solid state with most probably water in the remaining positions giving a mean Ca-O bond distance of ca. 2.36 angstrom. The iron(III) alkyl-N-iminodiacetate complexes have low solubility due to a strong tendency to form polymeric structures. Depending on pH in the solution at their preparation, the degree of hydrolysis in the resulting compound(s) may differ. In the solid state, the polymeric iron(III) alkyl-N-iminodiacetate compounds seem to have the mean composition Fe2O(C-x-IDA)(5); the mean Fe-O bond distances to the oxo group and the alkyl-N-iminodiacetate ligands are 1.92 and 2.02 angstrom, respectively. In these complexes the nitrogen atoms are bound at much longer bond distances, 0.1-0.2 angstrom, than the carboxylate oxygens. This distribution with short strong Fe-O bonds and much longer and weaker Fe-N bonds is also found in most other structurally characterized iron(III) carboxylated amine/polyamine complexes. The chromium(III) alkyl-N-iminodiacetate complexes are octahedral in both solution and solid state, and the low solubility of the solid compounds indicates a polymeric structure with the ligands bridging chromium(III) ions. Also, chromium(III) binds oxygen atoms in carboxylated amines at significantly shorter distance than the nitrogen stoms. The chromium(III) alkyl-N-iminodiacetate complexes display such slow kinetics at titration with strong base that the back-titration with strong acid shows completely different acid-base properties, thus the acid-base reactions are irreversible

ADHD in international adoptees: a national cohort study

Several investigators have reported an increased frequency of attention/hyperactivity symptoms in international adoptees, though population-based studies are lacking. In this national cohort study, we aimed to determine the prevalence of ADHD medication in international adoptees in Sweden, in comparison to the general population. A further purpose was to study gender, age at adoption and region of origin as predictors of ADHD medication in international adoptees. The study population consisted of all Swedish residents born in 1985–2000 with Swedish-born parents, divided into 16,134 adoptees, and a comparison population of 1,326,090. ADHD medications were identified in the Swedish Prescribed Drug Register during 2006. Logistic regression was used to calculate the odds ratios. The rates of ADHD medication were higher in international adoptees than in the comparison population for both boys (5.3 vs. 1.5% for 10–15-year olds) and girls (2.1 vs. 0.3% for 10–15-year olds). International adoptees from all regions of birth more often consumed ADHD medication compared with the majority population, but the age and sex adjusted odds ratios were particularly high for adoptees from Eastern Europe, Middle East/Africa and Latin America. Adjusting for maternal education and single parenthood increased the odds ratios even further. The risk also increased with higher age at adoption. Adoptees from Eastern Europe have a very high risk for ADHD medication. A structured identification and support programme should be tailored for this group. Adoptees from other regions have a more moderately increased risk, which should be communicated to adoptive parents and to professionals who care for adoptees in their clinical practice

Complex Formation Between Zinc(II) and Alkyl-N-iminodiacetic Acids in Aqueous Solution and Solid State

Removal of metal compounds from wastewater using processes where metals can be removed and valuable chemicals recycled is of significant industrial importance. Chelating surfactants are an interesting group of chemicals to be used in such applications. Carboxylated polyamines are a promising group to be used in such processes. To apply carboxylated polyamines as chelating surfactants, detailed knowledge of the solution chemistry, including complex formation, kinetics and structures of pure fundamental systems, is required. In this study zinc(II) alkyl-N-iminodiacetate systems with varying length of the alkyl chain have been studied. Acidic and stability constants have been studied by potentiometry, and the structures of both solids and aqueous solutions have been determined by EXAFS. Zinc(II) forms two strong complexes with alkyl-N-iminodiacetates in aqueous solution. In an attempt to determine the acidic constants of these complexes, the deprotonation of the nitrogen atom in the complex bound ligands, it was observed that this reaction is very slow and no accurate values could be obtained. The bis(alkyl-N-iminodiacetato)zincate(II) complexes take, however, up two protons in the pH region 3-7, which means that this complex is approximately singly protonated in the pH region 3-7 and doubly protonated at pH < 3. The bis(n-hexyl-N-iminodiacetato)zincate(II) complex at pH = 13 has a distorted octahedral configuration with four short strong Zn-O bonds at 2.08(1) angstrom, while the Zn-N bonds are weaker at much longer distance, 2.28(2) angstrom. Similar configurations are also found in most reported structures of zinc(II) complexes with carboxylated amines/polyamines. The singly protonated complex seems to be five-coordinate, with four Zn-O bond distances at ca. 2.03 angstrom, and a single Zn-N bond distance in the range 2.15-2.25 angstrom. The relationship between the structure of the protonated bis(n-hexyl-N-iminodiacetato)zincate(II) complex and the slow kinetics in the region pH = 3-7 are discussed

Analysis of current and alternative phenol based RNA extraction methodologies for cyanobacteria

<p>Abstract</p> <p>Background</p> <p>The validity and reproducibility of gene expression studies depend on the quality of extracted RNA and the degree of genomic DNA contamination. Cyanobacteria are gram-negative prokaryotes that synthesize chlorophyll <it>a </it>and carry out photosynthetic water oxidation. These organisms possess an extended array of secondary metabolites that impair cell lysis, presenting particular challenges when it comes to nucleic acid isolation. Therefore, we used the NHM5 strain of <it>Nostoc punctiforme </it>ATCC 29133 to compare and improve existing phenol based chemistry and procedures for RNA extraction.</p> <p>Results</p> <p>With this work we identify and explore strategies for improved and lower cost high quality RNA isolation from cyanobacteria. All the methods studied are suitable for RNA isolation and its use for downstream applications. We analyse different Trizol based protocols, introduce procedural changes and describe an alternative RNA extraction solution.</p> <p>Conclusion</p> <p>It was possible to improve purity of isolated RNA by modifying protocol procedures. Further improvements, both in RNA purity and experimental cost, were achieved by using a new extraction solution, PGTX.</p

Skapandet av en modernistisk trädgård

Examensarbetet "Skapandet av en modernistisk trädgård" är resultatet av ett samarbete mellan en TRING odlare och en TRING designer som bestämde sig för att arbeta gränsöverskridande och dra nytta av varandras specialområden för att skapa en vacker och hållbar trädgård i modernistisk anda till ett fritidshus i Stora Rör på Öland

A national cohort study of parental socioeconomic status and non-fatal suicidal behaviour-the mediating role of school performance

Background: A link between low parental socioeconomic status and mental health problems in offspring is well established in previous research. The mechanisms that explain this link are largely unknown. The present study investigated whether school performance was a mediating and/or moderating factor in the path between parental socioeconomic status and the risk of hospital admission for non-fatal suicidal behaviour. Methods: A national cohort of 447 929 children born during 1973-1977 was followed prospectively in the National Patient Discharge Register from the end of their ninth and final year of compulsory school until 2001. Multivariate Cox proportional hazards and linear regression analyses were performed to test whether the association between parental socioeconomic status and non-fatal suicidal behaviour was mediated or moderated by school performance. Results: The results of a series of multiple regression analyses, adjusted for demographic variables, revealed that school performance was as an important mediator in the relationship between parental socioeconomic status and risk of non-fatal suicidal behaviour, accounting for 60% of the variance. The hypothesized moderation of parental socioeconomic status-non-fatal suicidal behaviour relationship by school performance was not supported. Conclusions: School performance is an important mediator through which parental socioeconomic status translates into a risk for non-fatal suicidal behaviour. Prevention efforts aimed to reduce socioeconomic inequalities in non-fatal suicidal behaviour among young people will need to consider socioeconomic inequalities in school performance

Chest X-rays are less sensitive than multiple breath washout examinations when it comes to detecting early cystic fibrosis lung disease

Aim: Annual chest X-ray is recommended as routine surveillance to track cystic fibrosis (CF) lung disease. The aim of this study was to investigate the clinical utility of chest X-rays to track CF lung disease. Methods: Children at Gothenburg\u27s CF centre who underwent chest X-rays, multiple breath washouts and chest computed tomography examinations between 1996 and 2016 were included in the study. Chest X-rays were interpreted with Northern Score (NS). We compared NS to lung clearance index (LCI) and structural lung damage measured by computed tomography using a logistic regression model. Results: A total of 75 children were included over a median period of 13\ua0years (range: 3.0-18.0\ua0years). The proportion of children with abnormal NS was significantly lower than the proportion of abnormal LCI up to the age of 4\ua0years (p\ua0&lt;\ua00.05). A normal NS and a normal LCI at age 6\ua0years were associated with a median (10-90th percentile) total airway disease of 1.8% (0.4-4.7%) and bronchiectasis of 0.2% (0.0-1.5%). Conclusion: Chest X-rays were less sensitive than multiple breath washout examinations to detect early CF lung disease. The combined results from both methods can be used as an indicator to perform chest computed tomography less frequently

Aerodynamic and aeroacoustic comparison of optimized high-speed propeller blades

The Boxprop is a high-speed propeller concept intended for aircraft engines, which features blade pairs connected at the tip in order to decrease tip vortex strength, possibly reducing noise and improving aerodynamic performance relative to conventional high-speed propellers. This paper investigates the aerodynamic and aeroacoustic performance of three aerodynamically optimized high speed propellers; a 6-bladed conventional propeller, a 12-bladed conventional propeller, and a 6-bladed Boxprop. Performance results will be be compared for the three designs, with a focus on sectional performance and wake flow characteristics, and will show that the 6-bladed Boxprop performance lies somewhat in-between its 6 and 12-bladed conventional counterparts. The noise level at various observer positions is presented, and shows that the noise roughly follows the values of efficiency for the three propellers, with the Boxprop noise level being higher than the 12-bladed conventional propeller, but lower than the 6-bladed one. The lower blade loading and higher efficiency of the Boxprop relative to the 6-bladed conventional propeller results in slightly lower levels of noise at cruise

Effects of Soil Compaction and Organic Carbon Content on Preferential Flow in Loamy Field Soils

Abstract: Preferential flow and transport through macropores affect plant water use efficiency and enhance leaching of agrochemicals and the transport of colloids, thereby increasing the risk for contamination of groundwater resources. The effects of soil compaction, expressed in terms of bulk density (BD), and organic carbon (OC) content on preferential flow and transport were investigated using 150 undisturbed soil cores sampled from 15 × 15–m grids on two field sites. Both fields had loamy textures, but one site had significantly higher OC content. Leaching experiments were conducted in each core by applying a constant irrigation rate of 10 mm h−1 with a pulse application of tritium tracer. Five percent tritium mass arrival times and apparent dispersivities were derived from each of the tracer breakthrough curves and correlated with texture, OC content, and BD to assess the spatial distribution of preferential flow and transport across the investigated fields. Soils from both fields showed strong positive correlations between BD and preferential flow. Interestingly, the relationships between BD and tracer transport characteristics were markedly different for the two fields, although the relationship between BD and macroporosity was nearly identical. The difference was likely caused by the higher contents of fines and OC at one of the fields leading to stronger aggregation, smaller matrix permeability, and a more pronounced pipe-like pore system with well-aligned macropores