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1.
Several models have been developed in order to categorize the numerous expressions that people use in order to describe their emotional experiences. The focus of the present study is on one of these theoretical classifications proposed by Pekrun (1992) specifically concerning emotions which are directly related to learning and achievement in mathematics. In his model, emotions are classified according to their valence (positive vs. negative) and their level of activation. In testing the assumptions of this model, we investigated students' enjoyment, anxiety, anger and boredom experienced before, during, and after the completion of a math test. Correspondence analyses which were used to generate a graphical illustration of structural interrelationships between these emotions provide empirical support for the theoretical classification. 相似文献
2.
L. Goetz E. Sabbioni E. Marafante J. Edel-Rade C. Birattari M. Bonardi 《Journal of Radioanalytical and Nuclear Chemistry》1981,67(1):183-192
Carrier-free201+202Tl have been produced in the cyclotron by (p, xn) reactions on mercury targets and used as a trcer for thallium in metallobiochemistry
of heavy metal pollution. The separation of201+202Tl radioisotopes from Hg involved a solvent extraction method leading to labelled univalent Tl(I) ions. This radioactive solution
was used to prepare different201+202Tl labelled compounds such as inorganic Tl(III) ions and organic dimethylthallium. Quality controls have been applied directly
on the different radioactive solutions immediately before their administrations to rats in order to ensure that thallium had
the chemical form expected. A summary of the main results concerning different aspects of the metabolic investigations on
rats such as absorption, retention, excretion, transplacental transport and influence of the different chemical forms of thallium
on its metabolism is also reported. 相似文献
3.
Frederick J. Goetz 《Journal of heterocyclic chemistry》1967,4(1):80-84
A definite tautomeric relationship has been found between 2-arylbenzothiazolines (I) and 2-(benzylideneamino)thiophenols (II). In a reaction characteristic of the closed ring structure (I), 2-arylbenzothiazolines were oxidized in high yield with benzoyl peroxide to the corresponding 2-arylbenzothiazoles (III). Reactions characteristic of the open ring structure (II) include the formation of the potassium salt of the open ring structure (IV) by reaction of 2-arylbenzothiazolines with potassium t-butoxide in toluene and oxidation of 2-arylbenzothiazolines to bis-[2-(benzylideneamino)phenyl] disulfides (V) by hydrogen peroxide in methanol. 相似文献
4.
Singh SB Ball RG Bills GF Cascales C Gibbs JB Goetz MA Hoogsteen K Jenkins RG Liesch JM Lingham RB Silverman KC Zink DL 《The Journal of organic chemistry》1996,61(22):7727-7737
Farnesyl-protein transferase (FPTase) is an enzyme responsible for the farnesylation of Ras protein. Farnesylation is required for cell-transforming activity in several tumor-types, and therefore, inhibition of FPTase activity may be a potential target for anticancer drugs. Our continued search for novel inhibitors led to the isolation of a number of bicyclic resorcinaldehyde cyclohexanone derivatives named here cylindrols A(1) to A(4), cylindrols B and B(1), and a number of known compounds, from Cylindrocarpon lucidum. The compounds were isolated by bioassay-guided separation using Sephadex LH-20, silica gel, and reverse phase HPLC. Structures were elucidated by extensive application of 2D NMR and X-ray crystallography. The determination of absolute stereochemistry was accomplished by CD measurements. Chemical transformations of the most abundant compound resulted in a number of key derivatives which were critical for the evaluation of structure activity relationship. These compounds are members of ascochlorin family and showed a wide range of inhibitory activity (0.7 &mgr;M to >140 &mgr;M) against FPTase. The FPTase activity was noncompetitive with respect to both substrates. Isolation, structures, chemical transformations, and FPTase activity are discussed in detail. 相似文献
5.
6.
The reaction of isatoic anhydrides with the anion derived from ethyl o-fluorobenzoylacetate to furnish [1]benzopyrano-[3,2-c]quinolines is described. An analogous reaction with 3-azaisatoic anhydride furnishes 1b , or with tricyclic anhydride 3 , system 4 is isolated. Spectral data is also discussed. 相似文献
7.
The reaction of 2-chloronicotinonitrile with N-methylmethanesulfonamide and subsequent treatment with base furnished the novel pyrido[2,3-c]-1,2-thiazine ring system 7 . Spectrally, it was determined that the predominant tautomer in solution was the 4-amino form 7a . Acidic hydrolysis of 7 furnished the 4-oxo tautomer 8b , compound 8b was alkylated on oxygen with 1-bromopentane in the presence of sodium hydride. Reaction of 8b with isocyanates occurs at the 3 position to produce carboxanilides 10 . Spectral characteristics of these compounds are also discussed. 相似文献
8.
Phytochemistry of genus Gentiana, XXIV. New C-glycosylflavones from the leaves of Gentiana asclepiadea L. p-Hydroxybenzoyl-2″-isoorientin-4′-O-β-D-glucoside ( 1 ) was isolated from the leaves of Gentiana asclepiadea L. by means of column chromatography. This is the first occurrence in nature of a p-hydroxybenzoate of isoorientin. p-Hydroxybenzoyl-2″-isoorientin ( 2 ) was also shown to be present in the same plant. 相似文献
9.
Goetz E. Hardtmann Gabor Koletar Oskar R. Pfister 《Journal of heterocyclic chemistry》1975,12(3):565-572
Three methods for the preparation of N-substituted 2H-3,1-benzoxazine-2,4(1H)diones (isatoic anhydrides) (1) utilizing 2-chloro-, 2-nitrobenzoic acids and N-unsubstituted isatoic anhydrides as starting materials, are described. 相似文献
10.
Petra Krystek Jutta Tentschert Yacine Nia Benedicte Trouiller Laurent Noël Mario E. Goetz Arnaud Papin Andreas Luch Thierry Guérin Wim H. de Jong 《Analytical and bioanalytical chemistry》2014,406(16):3853-3861
Nanosized titanium dioxide (TiO2) is one of the most interesting and valuable nanomaterials for the construction industry but also in health care applications, food, and consumer goods, e.g., cosmetics. Therefore, the properties associated with this material are described in detail. Despite its widespread use, the analytical determination and characterization of nanosized metal oxides is not as straightforward as the comparatively easy-to-detect metallic nanoparticles (e.g., silver or gold). This study presents the method development and the results of the determination of tissue titanium (Ti) levels after treatment of rats with the nanosized TiO2. Total Ti levels were chosen to evaluate the presence and distribution of TiO2 nanoparticles. A procedure consisting of incubation with a mixture of nitric acid (HNO3) and hydrofluoric acid (HF), and heating was developed to digest tissues and TiO2 nanomaterials in order to determine the total Ti content by inductively coupled plasma mass spectrometry (ICPMS). For the inter-laboratory comparison, altogether four laboratories analyzed the same samples upon digestion using the available ICPMS equipment. A major premise for any toxicokinetic study is the possibility to detect the chemical under investigation in biological samples (tissues). So, the study has to be performed with a dose high enough to allow for subsequent tissue level measurement of the chemical under investigation. On the other hand, dose of the chemical applied should not induce over toxicity in the animal as this may affect its absorption, distribution, metabolism, and excretion. To determine a non-toxic TiO2 dosage, an acute toxicity study in rats was performed, and the organs obtained were evaluated for the presence of Ti by ICPMS. Despite the differences in methodology and independent of the sample preparation and the ICPMS equipment used, the results obtained for samples with Ti concentrations >4 μg Ti/g tissue agreed well. Figure
Major Ti concentrations in micrograms per gram of organ as determined by different laboratories. 相似文献