Specific coil noise induced by magnetic matter at phase transition temperature

It was found that a polycrystalline gadolinium sample forming part of a closed magnetic loop threading a coil induced substantial coil noise when its temperature corresponded to the transition temperature of gadolinium.     

NMR-Untersuchung der Wasser/Methanol-L?sungen des Formaldehyds

Ohne Zusammenfassung     

Potential of pulsating point charge in warm isotropic plasma

An expression for the potential of a pulsating point charge in a warm isotropic plasma known from previous work is derived in an independent way. This approach offers a possibility to calculate the plasma response as a Laplace instead of Fourier integral and may give some insight even into problems without spherical symmetry.     

Heteroelectrocyclic reaction of 4‐azido‐3‐hydrazonoalkyl‐quinolines to 2‐arylaminopyrazolo[4,3‐c]quinolones

4‐Azido‐3‐acylquinolones 4 obtained from 4‐hydroxy derivatives 1 via tosylates 3 or chlorides 5, reacted with arylhydrazines 6 to generate 4‐azido‐3‐hydrazonoalkylquinolines 7. Thermolysis of 7 gave ring closure products which were assigned to 2‐arylaminopyrazolo[4,3‐c]quinolones 10. The thermal decomposition conditions of the azides 4 and 7 were studied by differential scanning calorimetry (DSC).     

Fröhlich coherent states: Implications for thermal sensitivity of cells

The inactivation rate of cells induced by heat in biological systems exhibits significant variations. The Fröhlich hypothesis of coherent vibrations is used to explain the observed differences between thermal sensitivities of malignant cells and their healthy counterparts. The resistance of the cellular membrane to the thermal fluctuations, pore creation, and membrane permeability increase may depend on the coherent state energy. A higher membrane permeability results in a lower cell survival rate when heated to the hyperthermic range.     

Structure of intermetallic phases in Al-free galvannealed zinc coatings

Galvannealed coatings of thickness of (20–40) μm were prepared on the ultra low carbon (ULC) steel substrate. Metalography analysis was carried out to obtain the phase composition of coatings. Coatings were then transfered onto a polyacrylate foil. Transmission spectra yielding all the positions of iron within the coating thickness were measured. The doublet of zeta phase occured only after short annealing times, lower annealing temperatures and longer dipping times. Parameters of three sites of delta phase were observed to approach equilibrium values at higher annealing temperatures and longer annealing times. These changes are ascribed to diffusion transformations in the coatings during annelaing. Presented at International Colloquium “M?ssbauer Spectroscopy in Materials Science”, Všemina, Czech Republic, June 1–4, 2004.     

Predicting Collagen Triple Helix Stability through Additive Effects of Terminal Residues and Caps

Collagen model peptides (CMPs) consisting of proline-(2S,4R)-hydroxyproline-glycine (POG) repeats have provided a breadth of knowledge of the triple helical structure of collagen, the most abundant protein in mammals. Predictive tools for triple helix stability have, however, lagged behind since the effect of CMPs with different frames ([POG]_n, [OGP]_n, or [GPO]_n) and capped or uncapped termini have so far been underestimated. Here, we elucidated the impact of the frame, terminal functional group and its charge on the stability of collagen triple helices. Combined experimental and theoretical studies with frame-shifted, capped and uncapped CMPs revealed that electrostatic interactions, strand preorganization, interstrand H-bonding, and steric repulsion at the termini contribute to triple helix stability. We show that these individual contributions are additive and allow for the prediction of the melting temperatures of CMP trimers.     

Thermally Induced Chemiluminescence of Barley Leaves

Abstract— An unconventional band in the thermoluminescence glow curve of barley leaves at about +50°C was examined. In contrast to bands usually observed around +50°C, this band (designated as CL) is not related to photosynthetic electron transport in photosystem II. The appearance of the CL band (1) requires previous freezing of the sample, (2) is not influenced by light excitation and (3) depends on the presence of oxygen. In pure oxygen the glow curves for both leaves and chloroplast suspension exhibit three maxima at about +40°C, +65°C and +90°C. Based on the emission spectra of the CL band and measurements with etiolated leaves, we suppose that the majority of emission corresponding to the CL band originates from chlorophyll. A lipoxygenase inhibitor, butylated hydroxytoluene, and sodium azide decrease the intensity of the CL band. We propose that the mechanism leading to emission of the CL band involves thermally stimulated production of an active oxygen species that results in lipid peroxidation.     

Spectral characterization of chlorophyll fluorescence in barley leaves during linear heating. Analysis of high-temperature fluorescence rise around 60 degrees C

The spectral characteristics of chlorophyll fluorescence and absorption during linear heating of barley leaves within the range 25-75 degreesC (fluorescence temperature curve, FTC) were studied. Leaves with various content of light harvesting complexes (green, Chl b-less chlorina f2 and intermittent light grown) revealing different types of FTC were used. Differential absorption, emission and excitation spectra documented four characteristic phases of the FTC. The initial two FTC phases (a rise in the 46-49 degreesC region and a subsequent decrease to about 55 degreesC) mostly reflected changes in the fluorescence quantum yield peaking at about 685 nm. A steep second fluorescence rise at 55-61 degreesC was found to originate from a short-wavelength Chl a spectral form (emission maximum at 675 nm) causing a gradual blue shift of the emission spectra. In this temperature range, a clear correspondence of the blue shift in the emission and absorption spectra was found. We suggest that the second fluorescence rise in FTC reflects a weakening of the Chl a-protein interaction in the thylakoid membrane.