[en] The paper discusses one of the promising approaches for the synthesis of graphene formed at the interface in the Langmuir bath. The results of the investigation of the formation of pyren monolayers (both initial elements of graphene) and a mixture of pyrene and arachidic acid are presented. It is shown how the mechanical characteristics of a monolayer change when pyrene is added to a mixture with arachidic acid: the rigidity of the monolayer increases and the compression modulus decreases. Also studied the hypothesis that arachidic acid can act as a single crystal substrate on which it is possible to form an ordered layer of pyrene. (paper)

[en] A highly oriented crystalline metal-organic framework (MOF) nanofilm array was prepared and used for surface-assisted laser desorption ionization mass spectrometry (SALDI-MS) for determination of small molecules. The MOF nanofilm was characterized using scanning/transmission electron microscopy, X-ray diffraction, and ultraviolet-visible spectroscopy. Different small molecules (anthracene, n-eicosanoic acid, Rhodamine B) were successfully determined by this MOF nanofilm array with limits of detection (LOD) between 0.1–5 ng·mL⁻¹ and limits of quantification (LOQ) between 1 and 10 ng·mL⁻¹. Compared to previously reported MOF-based SALDI-MS, this array exhibits better reproducibility (3.3–5.2%) and recovery (89–105%). The intensity of the MS peak remains the same after 25 repeated cycles. This indicates good repeatability. This MOF nanofilm-based SALDI-MS array can be used for determination of fatty acid and Rhodamine B in real samples with good recovery (83–106%).

[en] Radioimmunoassay is the most widely used method for determination of eicosanoids in biological material. Although this technique is, in principle, simple, radioimmunological data generally require extensive validation procedures. Here some examples for such methods are presented with special emphasis on the determination of cysteinyl-leukotrienes. (author)

[en] Deuterated lipoxygenase and cyclooxygenase derivatives of eicosatetraenoic acid (arachidonic acid) and their metabolites are indispensable tools for organic trace analysis, biomedical studies, and mechanistic investigations on the corresponding endogenous (unlabelled) eicosanoids. Methods for the preparation of deuterated eicosanoids are reviewed. (author)

[en] Eicosanoids is a collective term for prostaglandins, thromboxanes, leucotrienes asnd various hydroxy and hydroperoxy fatty acids. This brief overview considers major findings on the role of eicosanoids in the expression and modification of radiation damage, with special emphasis on its therapeutic potential. (UK)

[en] Langmuir-Blodgett (LB) films formed of some organic dyes, namely 3,4,9,10-tetra-(n-alkoxy-carbonyl)-perylenes, and their mixtures with arachidic acid have been studied. The electronic absorption and fluorescence spectra were recorded. The results obtained have led to conclusions about formation of self-aggregates of dye molecules at the air-solid substrate interface. The absorption spectra have indicated that in the ground state some fraction of J-aggregates can be formed, whereas the fluorescence spectra have been dominated by the emission from excimer states

[en] 5-hydroxyeicosatetraenoic acid (5-HETE) lactone was converted to omega-aminopropylamide and coupled to BSA using 1,5-difluoro-2,4-dinitrobenzene as a coupling agent. Antibodies were developed by immunizing rabbits with 5-HETE-BSA conjugate for 11 months with monthly boosters. The antiplasma at 1 to 800 dilution bound 35% of the total radioactivity of the tritiated 5-HETE (150 Ci/mmole). The detection limit of the RIA (one SE of the buffer control) was 19 picogram. The antiplasma showed the greatest cross reactivity (0.24%) with LTB₄ among compounds tested (arachidonic acid, diarachidonyl phosphatidyl choline, linoleic acid, dilinoeyl phosphatidyl choline, linolenic acid, LTB₄, 5,12-diHETE, 5,15-diHETE, 15-HETE, 12-HETE, TXB₂ and other major prostaglandins). When the ethanol extract of rat macrophages (peritoneal), stimulated by Calcium ionophore, was injected into HPLC and each fraction was assayed for 5-HETE by RIA, there was only one immunoreactive peak which appeared at fractions corresponding to the elution time of 5-HETE standard. RIA for LTB₄ showed that the sample also contained LTB₄ and 12-HETE. Thus, this antiplasma can be used to monitor 5-HETE, which is a relatively stable relic of arachidonic acid metabolism via 5-lipoxygenase pathway, synthesized from the endogenous precursor in various biological samples

[en] A significant difference in retention time between unlabeled and the corresponding multi-tritium-labeled eicosanoid has been observed in the high performance liquid chromatography (HPLC) analysis of 11 eicosanoids. Variations in retention time range from 3-7%, depending on the separation conditions as well as the number and position of the tritium substitution. Multi-tritium-labeled eicosanoids were eluted earlier than the corresponding unlabeled eicosanoid in reversed phase HPLC, whereas no isotope effect was seen with ¹⁴C- and ³H₂-eicosanoids. Considerations must be given to this tritium isotope effect whenever both multi-tritium-labeled and unlabeled eicosanoids are used for HPLC cochromatography or recovery studies. (author)

[en] A catalase monolayer adsorbed on a layer of arachidic acid deposited on a solid support was irradiated with 100 keV electrons simulating the conditions of electron microscopic imaging. Effective doses were calculated taking into account the angular and energy distribution of backscattered electrons. Enzymatic inactivation was chosen as the criterion for damage and was monitored by a rapid and quantifiable but nevertheless sensitive assay. Dose-response curves revealed that inactivation is a one-hit--multiple-target phenomenon, which is consistent with biochemical evidence for a cooperative function of subunits. The experimentally determined target size coincides fairly well with both calculated cross sections for inelastic interactions based on the atomic composition of catalase and with calculated cross sections for ionizing events based on the chemical bonds involved. This legitimates both types of calculations even for complex biomolecules

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