Oxidative desaturation of α-linolenic,linoleic, and stearic acids by human liver microsomes

The desaturation of stearic, linoleic, and α-linolenic acids by human liver microsomes were studied. The microsomes were isolated from liver biopsies obtained during operations. It was shown that human liver microsomes are able to desaturate 1-¹⁴C-α-linolenic acid to octadeca-6,9,12,15-tetraenoic acid; 1-¹⁴C-linoleic acid to γ-linolenic acid; and 1-¹⁴C-stearic acid to oleic acid in the same system described in the rat. However, the desaturation activity obtained was low compared to other mammals. This effect was attributed to fasting, premedication, or the anaesthesia.     

Echtzeit-Suchprozessor-Architekturen

This paper deals with design and implementation of a random access dual ported memory with a sustained bandwidth of 100 MByte/s. Data blocks can be stored and retained in arbitrary order. This goal is achieved by a specialized scarch-processor based on Field Programmable Gate Arrays (FPGAs). The main advantage is the hardware-implemented search in alphabetical search trees which garantees the real-time behaviour. The concept is extendable to other applications affording data-buffering with extremly high bandwidth.     

Investigation of the atomic-scale friction and energy dissipation in diamond using molecular dynamics

We have used molecular dynamics simulations to examine friction when two diamond (111) surfaces are placed in sliding contact. The essence of atomic-scale friction was shown to be the mechanical excitation (in the form of vibrational and rotational energy) of the interface lattice layers upon sliding. This excitation was propagated to the rest of the lattice, and eventually dissipated as heat. In general, this excitation increases with increasing applied load; therefore, the atomic-scale friction also increases with load. Flexible hydrocarbon species, chemically bound to the diamond surface, can lead to a significant reduction of mechanical excitation upon sliding at high loads, leading to lower friction. In addition to clarifying the effects of chemically-bound hydrocarbon groups on atomic-scale friction at diamond interfaces, these simulations might also yield insight into more complicated systems, e.g. Langmuir-Blodgett films, and aid in the design of low-friction coatings.     

DIAGENETIC HISTORY OF LATE PALAEOCENE POTENTIAL CARBONATE RESERVOIR ROCKS, KOPET-DAGH BASIN, NE IRAN

The Upper Palaeocene (Thanetian) Chehel-Kaman Formation in the Kopet-Dagh Basin of NE Iran is principally composed of carbonates with minor siliciclastics and evaporites. Six stratigraphic sections were measured and more than 1,000 samples were collected for petrographic analysis, together with analyses of carbon and oxygen isotopes and trace element content. Four major carbonate lithofacies (and 13 subfacies) have been identified in previous studies and are interpretd in terms of deposition in a shallow-marine environment.
The petrographic analyses indicate that the Chehel-Kaman Formation carbonates have undergone a complex diagenetic history which includes compaction, cementation, micritization, dissolution, silicification, dolomitization, neomorphism and fracturing. δ¹⁸O and δ¹³C values in Chehel-Kaman Formation limestones range between +0.8 and -15.1%₀ PDB, and -2.82 and +3.5%₀ PDB, respectively. These variations are interpreted to reflect meteoric and burial diagenetic processes. Variations in trace-element concentrations (Fe and Mn increased while Na decreased) also indicated the effects of meteoric flushing. The limestones appear to have been formed at about 28°C.
Chehel-Kaman Formation dolomites were divided into d1 (finely-crystalline) and d2 (coarsely-crystalline) types. Petrographic and geochemical results indicated that the d1 dolomites formed under sabkha conditions from a parental solution at around 26°C, while d2 dolomites formed during burial diagenesis with much hotter pore fluids (around 72°C). The paragenetic sequence indicates that primary porosity decreased during early stages of diagenesis, although secondary porosity was subsequently created improving the reservoir quality of the carbonates.