Search results for "amine"
showing 10 items of 7299 documents
Within and between firm trends in job polarization : the roles of globalization and technology
2019
AbstractWe analyze occupational polarization within and across firms using a census of matched employer–employee panel data from Finland in the period of 2000–2014. As in most industrialized countries, the Finnish occupational distribution has polarized over the last decades. Using decomposition analysis, we find that jobs involving low-level service tasks increase mostly through the entry dynamics, while the high-level abstract task share increases largely within continuing firms. Worker-level occupational mobility points to some skill upgrading within continuing firms, while labor force entry and retirement contribute the polarizing trend. Instrumental variables (IVs) regressions confirm …
Studies on the Correlation of Putrescine and Potassium Contents in the Needles of Spruce Trees
1995
Summary The correlation between the polyamine putrescine and the nutritional element potassium was examined in Picea abies trees at numerous natural stands in Germany. The amounts of potassium and putrescine in needles was analyzed and a linear negative correlation between the K + and putrescine contents was found, which is significant in the bulk of all stands as well as in subsets. The negative correlation becomes even more pronounced when only sites situated over 600 m with trees older than 60 years are included. While former investigations were concerned with experimental conditions of potassium concentrations in soil or nutrient solutions, the data presented here derive from natural ha…
Investigations on the Polyamine Content of Spruce Needles Relative to the Occurrence of Novel Forest Decline
1991
Summary Levels of free polyamines were monitored in needles of spruce trees [ Picea abies (L.) Karst.] during the course of two vegetation periods at five natural sites. The putrescine concentration in needles of damaged spruce trees was significantly higher than in needles of undamaged trees. This is e.g. impressively proved by the putrescine/spermidine-ratio. While undamaged trees show nearly similar putrescine and spermidine concentrations, damaged trees have five- to tenfold higher putrescine levels depending on the increasing state of damage. Thus, the content of putrescine in needles can be used as a qualified biochemical damage indicator of spruce trees. The physiological effects of …
Strongly-coupled PbS QD solids by doctor blading for IR photodetection
2016
Solution-processed QD solids are emerging as a novel concept for high-performance optoelectronic devices. In this work, doctor blading is proposed for the fabrication of strongly-coupled QD solids from a PbS nanoink for photodetection at telecom wavelengths. The key step of this procedure is the solid-state ligand exchange, which reduces the interparticle distance and increases the carrier mobility in the resulting strongly-coupled QD solid. This is accomplished by replacing the original long oleylamine molecules by shorter molecules like 3-mercaptopropionic acid, as confirmed by FTIR, TGA and XPS. Further, a detailed investigation with XPS confirms the air-stability of the QD solids and th…
2,3-Dihydro-3-methyl-2-nitrimino-1,3-thiazole
2000
The title compound ¿alternatively, 3-methyl-2-[oxido(oxo)hydrazono]-2,3-dihydro-1,3-thiazole¿, C(4)H(5)N(3)O(2)S, was obtained by methylation of N-(2-thiazolyl)nitramine. The molecule lies on a mirror plane and the thiazole ring is planar, regular in shape and aromatic. The S atom participates in the aromatic sextet via an electron pair on the 3p(z) orbital. In the crystal, the molecules are arranged in parallel layers, bound to each other by weak C-H.O and C-H.N hydrogen bonds and by S.O dipolar interactions, with an interlayer separation of 3.23 A.
Structural and vibrational study of the tautomerism of histamine free-base in solution.
2003
Infrared and Raman spectroscopy in H(2)O and D(2)O and quantum Density Functional calculations were used to determine the structure of histamine free-base in aqueous solution. A quantum mechanical study of the tautomeric equilibrium of histamine free-base in solution was performed at the 6-311G level. Electronic correlation energies were included by using the hybrid functional B3LYP. The solvent was simulated as a continuum characterized by a dielectric constant, and the quantum system (solute) was placed in an ellipsoidal cavity. Solute-solvent electrostatic interaction was calculated by means a multipolar moment expansion introduced in the Hamiltonian. Four relevant histamine conformation…
A new neuraminic acid derivative and three types of glycopeptides isolated from the Cuvierian tubules of the sea cucumber Holothuria forskali
1973
The Cuvierian tubules of Holothuria forskali Della Chiaje, a sea cucumber found in the Adriatic Sea, were investigated with regard to their carbohydrate moieties. From a Pronase digest of these tubules three types of carbohydrate units were isolated and characterized. 1. A high-molecular-weight glycopeptide fraction was shown to contain sulphated polyfucose, galactosamine, a uronic acid and a previously unknown neuraminic acid derivative. The sulphate was shown by i.r. analysis to be present as an O-ester. The carbohydrate unit was linked O-glycosidically to threonine and serine residues in the polypeptide chain. The hitherto unknown neuraminic acid derivative (Hf-neuraminic acid) was resis…
Detection of primary DNA damage in Chlamydomonas reinhardtii by means of modified microgel electrophoresis.
1997
The assessment of genotoxic potential in surface water requires test methods, among which are those that detect initial DNA damage in organisms of aquatic biocenosis. The microgel electrophoresis (MGE) "comet assay" was applied to a ubiquitous unicellular green alga (Chlamydomonas reinhardtii) to detect DNA damage caused by genotoxins. For this, the test protocol described by Singh NP et al. [Exp Cell Res 175: 184-191, 1988] was modified. Major modifications were the use of alkaline lysis buffer with ionic detergents and the reduction of preincubation and electrophoresis times. Short-time exposure of Chlamydomonas to the well-known genotoxicants 4-nitroquinoline-1-oxide (4-NQO), N-nitrosodi…
Lateral Habenula contribution in nicotine addiction: Focus on dopamine, GABA and serotonin interactions
2011
Compelling evidence has shown a pivotal role of dopaminergic function in drug addiction. Recently, the Habenula (Hb) has attracted a great deal of attention as another target for nicotine in the brain because of its role in regulating dopamine (DA), gamma-aminobutyric acid (GABA) and serotonin (5-HT) systems. Nicotine acts binding to acetylcholine receptors that are widely distributed in the brain. Interestingly, the receptor subtypes that mediate nicotine withdrawal responses are highly expressed in the Hb. Moreover, the block of habenular nicotinic receptors in animals chronically treated with nicotine enhances withdrawal responses once nicotine is discontinued. Furthermore, it has been s…
Preconcentration and speciation of chromium in waters using solid-phase extraction and atomic absorption spectrometry
2000
Abstract A method for the preconcentration and speciation of chromium was developed. After formation of an anionic compound with ethylenediaminetetraacetic acid (CrY − ), Cr (VI) and Cr (III) are retained on a strong anionic phase (SAX) and controlled elution with 0.5 M NaCl permits their speciation. The retention and elution conditions were optimised, and interferences due to the presence of other ions such as Mg(II), Mn(II), Sn(II), Fe(III), Ba(II), Al(III), Ca(II), chloride, iodine, bromide, fluoride, sulphate, phosphate, bicarbonate and nitrate were studied. The detection limits were 0.4 μg l −1 and 1.1 μg l −1 for Cr(III) and Cr(VI), respectively, and reproducibility was 9%. The result…