Search results for "SPECT"
showing 10 items of 28650 documents
Calidad de la farmacoterapia y seguridad de los pacientes en hemodiálisis tratados con estimulantes eritropoyéticos
2008
Objective: To assess an interdisciplinary programme for the improvement of pharmacotherapy quality and patient safety in patients with chronic renal disease who are treated with erythropoiesis-stimulating agents. Method: Observational, longitudinal study. Retrospective analysis (period A) and prospective analysis (period B) following implementation of the programme for haemoglobin values and monthly erythropoiesis- stimulating agent dosage. The proportion of patients with haemoglobin values within the target range (10-5-12.5 g/dl) and those with values above the safety limit (≥ 12.5g/dl) were compared every four months and the average percentage of time with haemoglobin values within the ta…
Der Zerfall des 2,4-sec100Nb
1972
The nuclide100Nb was produced by irradiation of enriched100Mo targets with 14 MeV-neutrons, and its decay properties were investigated employing scintillation and semiconductor spectrometers and coincidence techniques. A half-life of 2.4±0.3 sec and aQ β-value of 5.8±0.2 MeV were found. From 27 gamma-rays, 20 transitions, representing 95% of the observed gamma-ray intensity, could be placed in a decay scheme comprising 10 excited states of100Mo.
NMR Spectroscopic and quantum chemical characterization of the (E)- and (Z)- isomers of the penta-1,3-dienyl-2-cation
2003
Dilute solutions of the (E )− and (Z )− isomers of pent-1,3-dienyl-2-cations (1) were obtained from reaction of 4-chloro-1,2-pentadiene (2) with SbF5 in SO2ClF/SO2F2 at −135 °C using high-vacuum co-condensation techniques. The experimental NMR spectra of the mixture of the two isomers were compared with quantum chemical 13C NMR chemical shift calculations at HF-SCF, MP2, CCSD and CCSD(T) levels using MP2/tzp geometries. Quantum chemical shift calculations were performed with a tzp basis (9s5p1d/5s3p1d) for carbon and a dz basis (4s/2s) for hydrogen using gauge-including atomic orbitals (GIAOs). The HF-SCF calculations deviate significantly for the positively charged carbon atoms of the ally…
In-beam study of the 128, 130Xe nuclei
1981
Abstract The level structure of 128,130Xe has been studied in the (α, 2nγ) and (3He, 3nγ) reactions on enriched Te targets using in-beam γ-ray spectroscopic methods. For both nuclei the existing information about positive-parity level structure was enriched and many new negative-parity two-quasiparticle states were observed. Isomeric states with the half-lives of 63 ± 12 ns in 128 Xe and 4.8 ± 0.5 ns in 130 Xe were found. For collective positive-parity states the interacting boson model, and calculations based on Bohr hamiltonian were compared with the experimental data.
Determination of90Sr in environmental samples with resonance ionization spectroscopy in collinear geometry
1994
A new, fast technique for trace analysis of the radioactive isotopes89Sr and90Sr in environmental samples has been developed. Conventional mass separation is combined with resonance ionization spectroscopy in collinear geometry, which provides high selectivity and sensitivity. In addition, a chemical separation procedure for sample preparation has been developed. The described technique was used to determine the90Sr content in ≈ 870 m3 air samples collected near Munich during and shortly after the Chernobyl reactor accident in April 1986. The content of90Sr was measured to be 1.4 mBq per m3, corresponding to 1.6 × 109 atoms of90Sr per sample. This value is in good agreement with the results…
Future Aspects of Positron Spectroscopy
1987
In the first week of this conference experimentalists made us familiar with the features of the positron peaks observed in the collision of very heavy ions with atoms. We learned that these peaks are not understandable in terms of known positron production mechanisms like monoenergetic pair decay of excited nuclear levels or the proposed spontaneous positron production in superheavy atoms. In addition, theorists told us that, at present, also the interpretation that the positron peak structures originate from the decay of a previously not observed neutral particle is in contradiction to well-known experimental facts. Some of you may have, in addition, become confused by the results of the t…
β-decay of 35Ca
1999
Abstract The β-decay of the T z =− 5 2 nucleus 35 Ca was studied at the LISE3 spectrometer at GANIL. The 35 Ca decay scheme was deduced from its β-delayed proton emission into the ground and excited states of 34 Ar and from its β-delayed two-proton emission. The 35 Ca half-life was determined to be 25.7±0.2 ms. The measured transition strength function B(GT) is compared to results obtained from large-scale sd-shell model calculations.
Model compound synthesis for the structure determination of new unknown planar aromatic compounds originating from pulp mill
1991
Abstract Several model compounds have been synthesized for verification of the structures of new unknown planar aromatic compounds (UPACs) observed in high-resolution gas chromatography/low-resolution mass spectrometry analyses of the polychlorodibenzodioxins (PCDDs) and polychlorodibenzofurans (PCDFs) in pulp mill products, effluents, sediments and mussels. The mass spectra of synthetic alkyl polychlorodibenzofurans (C6-PCDFs) were different, but those of alkyl polychlorobibenzyls (C5-PCBBs) were very similar compared to the spectra of UPACs.
Crystal structures, infrared-spectra, and thermal behavior of calcium hydrogenselenite monohydrate, Ca(HSeO3)2 · H2O, and dicalcium diselenite bis(hy…
1986
Abstract Calcium hydrogenselenite monohydrate and dicalcium diselenite bis(hydrogenselenite) were synthesized and their crystal structures determined. Crystal data for Ca(HSeO3)2 · H2O: a = 6.911(2), b = 7.369(2), c = 6.739(2) A, α = 90.51(3)°, β = 90.93(3)°, γ = 107.46(2)°, V = 327.3(2) A3, space group P 1 (No. 2), dcalcd = 3.19 M gm−3, Z = 2, and R = 0.036 for 1503 reflections. Data for Ca2(HSeO3)2(Se2O5): a = 14.719(4), b = 7.059(2), c = 11.793(2) A, β = 117.96(2)°, V = 1082.3(4) A3, space group C2 c (No. 15), dcalcd = 3.52 Mg m−3, Z = 4, and R = 0.047 for 1251 reflections. Both structures form a three-dimensional network. The coordination polyhedron around calcium is a monocapped trigon…
Outer and inner coordination sphere chemistry of polyazacyclophane platinum(II) complexes. Crystal structure of [PtBr4]2(H4L1) · H2O (L1 = 2,6,9,13-t…
1997
Abstract The interaction of PtCl42− with the new azaparacyclophane 2,5,8,11-tetraaza[12]paracyclophane (L2) has been studied by 1H, 13C and 195Pt NMR spectroscopy. Three different complexes are detected as a function of pH, all of them presenting cis-arrangement of nitrogen donors and chloride anions. In the first one, formed at acidic pH, the central nitrogen atoms of the macrocyclic are coordinating to Pt(II) while the benzylic nitrogens remain protonated. Deprotonation of these nitrogens brings about a reorganisation of the complex, and the platinum is then coordinated by one benzylic nitrogen and the consecutive nitrogen in the macrocycle. This process can be monitored by NMR. Finally, …