The Synthesis of B-Hydroxytryptamines

It might be expected that B-hydroxylation of the side chain of tryptamine, 5-hydroxytryptamine (serotonin) and 5-methoxytryptamine would be of biological importance as it is the case with phenylethylamine group of biogenic amines (cf. tyramine-octopamine, dopamine-noradrenaline)

The Synthesis of B-Hydroxytryptamines

It might be expected that B-hydroxylation of the side chain of tryptamine, 5-hydroxytryptamine (serotonin) and 5-methoxytryptamine would be of biological importance as it is the case with phenylethylamine group of biogenic amines (cf. tyramine-octopamine, dopamine-noradrenaline)

Chromatography of Indole Derivatives on Sephadex G-15

The chromatographic · properties of indole derivatives, mainly biogenetically related to the plant growth hormone, indole-3-acetic acid, were studied on Sephadex G-15. The eluents used were 70°/o and 30°/o aqueous methanol, volatile ethylenediamine-acetate buffers of pH 4.2 and 7.4, and distilleo water adjusted to pH 7.4. The adsorption of indole derivatives to Sephadex could be preferentially ascribed to the heterocyclic nucleus which is bound by rt complex formation, as well as by hydrogen and hydrophobic bonding. The presence of a side chain, if subject to the same type of binding forces, results not only in stronger sorption but also in some exclusion in accordance with molecular weight. Furthermore, because of the carboxyl groups contained in Sephadex gels, positively charged compounds are bound by ion exchange, whereas negatively charged ones are acted upon by Donnan ion exclusion forces

Beta-hydroxytryptamines. I. Chemical Synthesis of 3-(2-Amino- 1-hydroxyethyl)indole and 5-Hydroxy-3-(2-amino-l-Hydroxy-ethyl)indole

From indole and 5-benzyloxyindole, respectively, the corresponding chloromethyl 3-indolyl ketones were prepared applying Guignard reaction with chloroacetyl chloride or Vilsmeier reaction with N,N-diethylchloroacetamide. By i. r. and n. m. r. spectroscopy it was proved that identical compounds were obtained in both reactions. After the substitution of the halide with dibenzylamino group and the reduction of the carbonyl group to hydroxyl with lithium alumi.num hydride, benzyl groups were removed by catalytic hydrogenation. 3-(2-Amino-1-hydroxyethy l)indole (beta-hydroxytryptamine) and 5-hydroxy-3-(2-amino-1-hydroxyethyl)indole (beta-hydroxyserotonin) were isolated in the form of crystalline creatinine sulphates. Solubility and satisfying stability in aqueous solutions make these salts suitable for biochemical and pharmaco\u27logical investigations

Zinc Sulfide Tubes Reinforced with Carbon Nanofibers

Zinc sulfide submicron and nanotubes with outer diameters in the range from 100 to 1000 nm were produced through chemical deposition from vapor under argon pressure. The novel process provides formation of ZnS tubes reinforced with carbon nanofibers. This is the first time that the ZnS tubes are grown with fibers during deposition

RECRYSTALLIZATION OF CERAMIC MATERIAL FABRICATED FROM Cd1-xZnxTe.

Binary and ternary A(illegible)B(illegible) compounds are conventionally grown from melt. This technique is very complicated and requires complex equipment to provide high pressures and high temperatures to grow stoichiometric compositions. New opportunities for designing materials used in the infrared technique and ionizing radiation detectors are opened by advantages in nanotechnology. In particular difficulties in Cd{sub 1-x}Zn{sub x}Te with various Zn content are traditionally used in infrared optics and as a material for ionizing radiation detectors. Zn concentration in the nanopowders produced by the new vapor deposition technique varies from x=0.02 to x=0.1, including the composition Cd{sub illegible}Zn{sub illegible}Te, which is the most promising as a material for ionizing radiation detectors working at room temperature without cooling

Magnetic Resonance of the Intrinsic Defects of the Spin-Peierls Magnet CuGeO3

ESR of the pure monocrystals of CuGeO3 is studied in the frequency range 9-75 GHz and in the temperature interval 1.2-25 K. The splitting of the ESR line into several spectral components is observed below 5 K, in the temperature range where the magnetic susceptibility is suppressed by the spin-Peierls dimerization. The analysis of the magnetic resonance signals allows one to separate the signals of the S=1/2- and S=1 defects of the spin-Peierls phase. The value of g-factor of these signals is close to that of the Cu-ion. The additional line of the magnetic resonance is characterized by an anomalous value of the g-factor and by the threshold-like increase of the microwave susceptibility when the microwave power is increasing. The ESR signals are supposingly attributed to two types of the planar magnetic defects, arising at the boundaries of the domains of the spin-Peierls state with the different values of the phase of the dimerization.Comment: LATEX-text, 12 PS-figures, typos corrected, LATEX-style change

Dynamical spin-electric coupling in a quantum dot

Due to the spin-orbital coupling in a semiconductor quantum dot, a freely precessing electron spin produces a time-dependent charge density. This creates a sizeable electric field outside the dot, leading to promising applications in spintronics. The spin-electric coupling can be employed for non-invasive single spin detection by electrical methods. We also consider a spin relaxation mechanism due to long-range coupling to electrons in gates and elsewhere in the system, and find a contribution comparable to, and in some cases dominant over previously discussed mechanisms.Comment: 4 pages, 2 figure

Effect of the spin-orbit interaction on the band structure and conductance of quasi-one-dimensional systems

We discuss the effect of the spin-orbit interaction on the band structure, wave functions and low temperature conductance of long quasi-one-dimensional electron systems patterned in two-dimensional electron gases (2DEG). Our model for these systems consists of a linear (Rashba) potential confinement in the direction perpendicular to the 2DEG and a parabolic confinement transverse to the 2DEG. We find that these two terms can significantly affect the band structure introducing a wave vector dependence to subband energies, producing additional subband minima and inducing anticrossings between subbands. We discuss the origin of these effects in the symmetries of the subband wave functions.Comment: 15 pages including 14 figures; RevTeX; to appear in Phys.Rev.B (15 Nov 1999