50 resultados para COBALT 60
Resumo:
The Indo-Pacific warm pool houses the largest zone of deep atmospheric convection on Earth and plays a critical role in global climate variations. Despite the region’s importance, changes in Indo-Pacific hydroclimate on orbital timescales remain poorly constrained. Here we present high-resolution geochemical records of surface runoff and vegetation from sediment cores fromLake Towuti, on the island of Sulawesi in central Indonesia, that continuously span the past 60,000 y.We show that wet conditions and rainforest ecosystems on Sulawesi present during marine isotope stage 3 (MIS3) and the Holocene were interrupted by severe drying between ∼33,000 and 16,000 y B.P. when Northern Hemisphere ice sheets expanded and global temperatures cooled. Our record reveals little direct influence of precessional orbital forcing on regional climate, and the similarity between MIS3 and Holocene climates observed in Lake Towuti suggests that exposure of the Sunda Shelf has a weaker influence on regional hydroclimate and terrestrial ecosystems than suggested previously. We infer that hydrological variability in this part of Indonesia varies strongly in response to high-latitude climate forcing, likely through reorganizations of the monsoons and the position of the intertropical convergence zone. These findings suggest an important role for the tropical western Pacific in amplifying glacial–interglacial climate variability.
Resumo:
n einer Festschrift für Helmut Schlichtherle, der die Pfahlbauforschung in Deutschland ganz wesentlich mitgeprägt hat, berichten 50 seiner Fachkollegen aus Frankreich, der Schweiz, Deutschland und Slowenien über aktuelle Ergebnisse der Siedlungsarchäologie. Die Beiträge befassen sich in erster Linie mit der Vernetzung von Siedlungen und deren ökonomischen Grundlagen, aber auch mit der Herstellung und sozialen Funktion von herausragenden Artefakten. Thematisiert wird auch die Frage nach den Anfängen hierarchischer Siedlungssysteme. Der zeitliche Rahmen erstreckt sich von den frühesten Bauernkulturen bis zur Völkerwanderungszeit. Mit dem Buch wird für die Siedlungsarchäologie ein Werk vorgelegt, das sowohl neue Erkenntnisse vorbringt als auch Perspektiven für die zukünftige Forschung aufzeigt. Es wird in den Fachbibliotheken der Universitäten, Denkmalämter und Museen unverzichtbar sein .
Resumo:
The preferred type of post-remission therapy (PRT) in patients with acute myeloid leukemia (AML) in first complete remission (CR1) is a subject of continued debate, especially in patients at higher risk of nonrelapse mortality (NRM), including patients >40 years of age. We report results of a time-dependent multivariable analysis of allogenic hematopoietic stem cell transplantation (alloHSCT) (n=337) versus chemotherapy (n=271) or autologous HSCT (autoHSCT) (n=152) in 760 patients aged 40-60 years with AML in CR1. Patients receiving alloHSCT showed improved overall survival (OS) as compared with chemotherapy (respectively, 57±3% vs 40±3% at 5 years, P<0.001). Comparable OS was observed following alloHSCT and autoHSCT in patients with intermediate-risk AML (60±4 vs 54±5%). However, alloHSCT was associated with less relapse (hazard ratio (HR) 0.51, P<0.001) and better relapse-free survival (RFS) (HR 0.74, P=0.029) as compared with autoHSCT in intermediate-risk AMLs. AlloHSCT was applied following myeloablative conditioning (n=157) or reduced intensity conditioning (n=180), resulting in less NRM, but comparable outcome with respect to OS, RFS and relapse. Collectively, these results show that alloHSCT is to be preferred over chemotherapy as PRT in patients with intermediate- and poor-risk AML aged 40-60 years, whereas autoHSCT remains a treatment option to be considered in patients with intermediate-risk AML.Leukemia advance online publication, 23 December 2014; doi:10.1038/leu.2014.332.
Resumo:
New coordination polymers [M(Pht)(4-MeIm)2(H2O)]n (M=Co (1), Cu (2); Pht2−=dianion of o-phthalic acid; 4-MeIm=4-methylimidazole) have been synthesized and characterized by IR spectroscopy, X-ray crystallography, thermogravimetric analysis and magnetic measurements. The crystal structures of 1 and 2 are isostructural and consist of [M(4-MeIm)2(H2O)] building units linked in infinite 1D helical chains by 1,6-bridging phthalate ions which also act as chelating ligands through two O atoms from one carboxylate group in the case of 1. In complex 1, each Co(II) atom adopts a distorted octahedral N2O4 geometry being coordinated by two N atoms from two 4-MeIm, three O atoms of two phthalate residues and one O atom of a water molecule, whereas the square-pyramidal N2O3 coordination of the Cu(II) atom in 2 includes two N atoms of N-containing ligands, two O atoms of two carboxylate groups from different Pht, and a water molecule. An additional strong O–H⋯O hydrogen bond between a carboxylate group of the phthalate ligand and a coordinated water molecule join the 1D helical chains to form a 2D network in both compounds. The thermal dependences of the magnetic susceptibilities of the polymeric helical Co(II) chain compound 1 were simulated within the temperature range 20–300 K as a single ion case, whereas for the Cu(II) compound 2, the simulations between 25 and 300 K, were made for a linear chain using the Bonner–Fisher approximation. Modelling the experimental data of compound 1 with MAGPACK resulted in: g=2.6, |D|=62 cm−1. Calculations using the Bonner–Fisher approximation gave the following result for compound 2: g=2.18, J=–0.4 cm−1.
Resumo:
Three new coordination polymers [M(Pht)(1-MeIm)2]n (where M=Cu (1), Zn (2), Co (3); Pht2−=dianion of o-phthalic acid; 1-MeIm=1-methylimidazole) and two compounds [M(1-MeIm)6](HPht)2 · 2H2O (M=Co (4), Ni (5)) have been synthesized and characterized by X-ray crystallography. The structures of 1–3 (2 is isostructural to 3) consist of [M(1-MeIm)2] building units connected by 1,6-bridging phthalate ions to form infinite chains. In complex 1, each copper(II) center adopts a square coordination mode of N2O2 type by two O atoms from different phthalate ions and two N atoms of 1-MeIm, whereas in 3 two independent metal atoms are tetrahedrally (N2O2) coordinated to a pair of Pht ligands and a pair of 1-MeIm molecules. There are only van der Waals interactions between the chains in 1, while the three-dimensional network in 3 is assembled by C–H⋯O contacts. In contrast to polymers 1–3 the structures of 4 and 5 (complexes are also isostructural) are made up of the [M(1-MeIm)6]2+ cation, two hydrogen phthalate anions (HPht−) and two H2O solvate molecules. The coordination around each metal(II) atom is octahedral with six nitrogen atoms of 1-MeIm. Extended hydrogen bonding networks embracing the solvate water molecules and a phthalate residue as well as the weak C–H⋯O interactions stabilize the three-dimensional structures. Magnetic studies clearly show that the magnetic ions do not interact with each other. Furthermore, in compound 4 we have another example of a highly anisotropic Co2+ ion with a rhombic g-tensor and large zero-field-splitting. The complexes were also characterized by IR and 1H NMR spectroscopy, thermogravimetric analysis, and all data are discussed in the terms of known structures.
Resumo:
The crystal structure of the first one-dimensional hetero-metallic compound containing thiocyanate as bridging ligands,{[Cu(cyclam)][Co(NCS)4]}n, has been determined, togetherwith a preliminary study of the magnetic properties.
Resumo:
BACKGROUND: In clinical practise the high dose ACTH stimulation test (HDT) is frequently used in the assessment of adrenal insufficiency (AI). However, there is uncertainty regarding optimal time-points and number of blood samplings. The present study compared the utility of a single cortisol value taken either 30 or 60 minutes after ACTH stimulation with the traditional interpretation of the HDT. METHODS: Retrospective analysis of 73 HDT performed at a single tertiary endocrine centre. Serum cortisol was measured at baseline, 30 and 60 minutes after intravenous administration of 250 µg synthetic ACTH1-24. Adrenal insufficiency (AI) was defined as a stimulated cortisol level <550 nmol/l. RESULTS: There were twenty patients (27.4%) who showed an insufficient rise in serum cortisol using traditional HDT criteria and were diagnosed to suffer from AI. There were ten individuals who showed insufficient cortisol values after 30 minutes, rising to sufficient levels at 60 minutes. All patients revealing an insufficient cortisol response result after 60 minutes also had an insufficient result after 30 minutes. The cortisol value taken after 30 minutes did not add incremental diagnostic value in any of the cases under investigation compared with the 60 minutes' sample. CONCLUSIONS: Based on the findings of the present analysis the utility of a cortisol measurement 30 minutes after high dose ACTH injection was low and did not add incremental diagnostic value to a single measurement after 60 minutes.