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Biomedical subjects

L Heinrich

Publications and source records attributed to L Heinrich.

6 recordsLinked to original sources

A Pentacoordinated Di-N-carboxamido-dithiolato-O-sulfinato-iron(III) Complex Related to the Metal Site of Nitrile Hydratase.

Postcoordination oxidation by dioxygen of one of the thiolate groups in a pentadentate N(2)S(3) ligand results in an iron(III) complex with two N-carboxamido, two thiolato, and one O-sulfinato ligands (see the CAMERON representation). This novel mixed coordination is similar to that determined for the inactive form of the nitrile hydratase from Rhodococcus sp. N-771, but differs by the O versus S binding of the sulfinato ligand.

Journal Article↗

Direct observation of the anchoring process during the adsorption of fibrinogen on a solid surface by force-spectroscopy mode atomic force microscopy.

Atomic force microscopy in a force-spectroscopy mode has been used to investigate the kinetics of the adsorption process of fibrinogen molecules on a silica surface. An original "approach/retraction" cycle of the tip/surface was used for this purpose. Fibrinogen molecules were adsorbed on the atomic force microscopy tip and were brought into contact with the silica surface for different interaction times varying from 5 to 2,000 ms. Multiple consecutive ruptures were observed. The mean number of ruptures nr per cycle increases steadily with the interaction time as well as the mean strength fr which varies from 300 pN for 5 ms to 1,400 pN for 2,000 ms. The minimal interaction time for a fibrinogen molecule to bind strongly to a silica surface during an adsorption process appears to lie between 50 and 200 ms. The histograms of the distances between two consecutive ruptures in one cycle exhibit maxima around 20-25 nm. This length is comparable to the characteristic distance between D and E globules of one fibrinogen molecule and suggests that fibrinogen molecules mainly adsorb through their D and E globules.

Fibrinogen↗

[Determination of phenols in coffee].

The structure and quantity of phenols, occurring in two different roasted Robusta coffees and in four samples of roast coffee, were investigated. Identification and quantification were carried out after special extraction procedures and clean-up methods by gas chromatography/mass spectrometry. The quantities of 35 phenols investigated ranged from below 0.1 mg/kg to more than 1000 mg/kg. Sixteen phenols were identified in coffee for the first time.

Coffee↗

[Occurrence of phenols in coffee melanoidins].

Compounds with higher molecular weights in roast coffee were separated by means of adsorption chromatography followed by gel chromatography which yielded seven fractions of different molecular weights. These were tested sensorially and degraded by Curie point pyrolysis high-resolution gas chromatography/mass spectrometry (HRGC/MS) about 100 products, among them 33 phenols, were found. The products were compared with fragments formed via model pyrolysis experiments on chlorogenic acid.

Chromatography, Gel↗

Causal attributions, sanctions, and normal mood variations.

The causal-locus hypothesis (CLH) asserts that persons making internal attributions for failure and external attributions for success experience more negative postoutcome moods than persons making the opposite attributions. Three experiments assessed the CLH. Although outcomes consistently affected moods and attributions, attributions did not affect moods. Significant correlations consistent with the CLH were also infrequently obtained. Another theory, the sanctioned-object hypothesis (SOH), was proposed for understanding how causal attributions lead to mood changes. This hypothesis asserts that the application of positive or negative sanctions to objects in the perceptual field is a central determinant of mood and that attributions affect mood when their content and salience activate sanctioning processes. A fourth experiment evaluated the competing theories. The results supported the SOH but not the CLH. The findings are discussed in terms of their implications for understanding mood variations and the effects that moods have on the construction of attributions and for adopting methodological alternatives that may be valuable for future laboratory research studying mood variations.

Affective Symptoms↗