Zur Analyse von Triglyceriden

Analysis of Triglycerides Only recently the analytic of triglycerides of natural fats and oils has found in HPLC an adaquate method. By means of HPLC it is possible to separate the glycerides of the fat with respect to partition number (PN) and to analyse the collected fractions by GLC with respect to carbon number (CN). This procedure yields a complete basis for calculation of the composition of triglyceride groups which are characterized by their carbon number and number of double bonds (e.g. C54:1). If the analytical data of each fraction are completed with the fatty acid composition, the fatty acid combination of the single triglycerides and their distribution can likely be characterized. This method was applied to triglyceride analysis of LOBRA oil. The obtained results are reported.     

Coulometric Titration of Iodine Values in Fats and Oils

Standard methods for the determination of iodine values of oils involve direct addition of halogen elements to the double bond. Since the reaction proceeds slowly there is a risk of substitution. A direct coulometrical titration method has been investigated.     

Regeneration of platinum-metal-based catalysts with carboxyphosphines as extractants

Separation of platinum-metal-based homogeneous catalysts was achieved by their conversion to complexes of functionalized phosphines of the general formulae R_3-n P[(CH₂) _x CO₂H)] _n , R = Me, Et, Ph,n = 1, 2, 3,x = 1, 2, and [(HO₂CCH₂)PCH₂]₂, followed by extraction of the complexes into aqueous phase. This approach to regeneration of platinum metals from reaction mixtures after carrying out homogeneously catalyzed reactions was demonstrated on 11 examples of various types of reactions with Ru, Rh, Pd, Os, Ir and Pt compounds as catalysts.     

Electrodeposition of CuNiW alloys: thin films,nanostructured multilayers and nanowires

Electrodeposition operating conditions were determined for the deposition of copper–nickel–tungsten alloys and compositionally, multilayered deposits. Multilayered alloys with one layer rich in Cu and the other layer rich in NiW were fabricated as both thin films and nanowires. The electrolyte contained 0.6 M Na₃C₆H₅O₇, 0.2 M Na₂WO₄, 0.3 M NiSO₄ and variable CuSO₄ concentration at a pH of 8 adjusted with ammonium hydroxide at 70 ± 2 °C. The deposit composition and current efficiency were characterized using rotating cylinder electrodes with and without a Hull configuration. Addition of Cu(II) to the electrolyte lowered the tungsten partial current density and hence the W wt% in the deposit. Thin film multilayered alloys, with a modulation in composition, were fabricated with pulse current deposition and conditions to selectively etch one layer was determined with a view towards fabricating nanotemplates. Nanowires with modulated composition were also demonstrated, electrodeposited into alumina nanoporous templates. However, the nanowire deposition was confounded by the formation of oxide during the modulation, and results herein recommend that the potential of the more noble step be more negative than −0.9 V versus SCE to avoid this situation, despite metallic alloy formation in unrecessed electrodes.     

Aneurysm of the splenic artery

The authors evaluate in the submitted paper the results of surgical treatment of embolization into the bifurcation of the abdominal artery at the Second Surgical Clinic in Brno during 1990-1996. A total of 5 patients was involved whereby in all a cardiac cause of the embolization was obvious. The authors deal also with the time which has elapsed between the development of complaints and surgery, the type of anaesthesia, average length of operation. The operation is implemented concurrently by two teams as antero- and retrograde simultaneous bi-transfemoral embolectomy. The authors emphasize the importance of the metabolic condition of the patient as well as cardiac and renal functions before, during and after surgery. They consider the application of peroperative haemodialysis essential. During the postoperative period it is important to find the objective cause of the cardiac deficiency and treat it. Their results--a 40% mortality are comparable with those of other specialized departments. By comparison with a similar group treated at the same department twenty years previously the authors find a decline in the incidence of this disease and explain this phenomenon by an increased number of cardiosurgical operations in this area.     

Electrodeposition of FeCoNiCu nanowires

Electrodeposition of FeCoNiCu/Cu nanometric, compositionally modulated alloy nanowires is presented. Pure Cu nanowires and Co-rich FeCoNiCu alloy nanowires were deposited from a single electrolyte. A double potential pulse scheme was used for multilayer deposition and significant anodic dissolution was observed during the low potential pulse. Galvanostatic triple pulses with a relaxation period were developed to minimize the local pH rise inside the nanopores during fabrication of the layered FeCoNiCu/Cu nanowires.     

Development of an Electrodeposited Nanomold from Compositionally Modulated Alloys

Electrodeposited multilayers of NiCu/Cu and NiFeCu/Cu were examined for nanoimprinting applications. Layer sizes on the order of 100 nm were deposited and the copper layer etched. Current efficiency and layer composition of electrolytes having different pH values were examined utilizing a rotating disk electrode. Due to large grain growth in the NiCu/Cu system, the bilayers resulted in a macroscopic waviness of the layers. Adding Fe in a small concentration successfully produced straight layers. As an example of the replication technique, the metal multilayer-etched stamp was used to cast the multilayer image in rubber and emboss it in Teflon^®.     

Verfahren zur selbsttätigen Chlorierung für die Ermittlung der oxydischen Einschlüsse in einem Chrom-Nickel-Stahl mit rd. 18% Cr und 8% Ni

Übersicht über das Schrifttum. Beschreibung und Arbeitsweise des Gerätes. Erprobung an Rückständen aus einem Stahl mit 0,10% C, 17,5% Cr, 1,6% Mo, 14,0% Ni, 0,7% Nb, 0,26% Ti und 0,3% W. Verhalten von Eisenoxyd und Manganoxyd bei längerer Chlorierungsdauer. Anwendung auf Stähle mit 18% Cr und 8% Ni sowie 18% Cr und 10% Ni, mit und ohne Molybdän, Niob und Titan, die zum Teil unter Argon, im Vakuum und im Elektronenstrahlofen umgeschmolzen waren.     

HPLC of triglycerides

Triglyceride separation was investigated on a reverse phase high performance liquid chromatography (HPLC) column using two different solvent systems. Complete separation of model compounds differing by two methylene groups was achieved. Partial or complete separation was also observed in critical pairs; for example, the different types of triglycerides consisting of palmitic and oleic acids. This observation was confirmed on natural oils (coconut oil, palm kernel oil).     

Melectin: a novel antimicrobial peptide from the venom of the cleptoparasitic bee Melecta albifrons

A novel antimicrobial peptide designated melectin was isolated from the venom of the cleptoparasitic bee Melecta albifrons. Its primary sequence was established as H-Gly-Phe-Leu-Ser-Ile-Leu-Lys-Lys-Val-Leu-Pro-Lys-Val-Met-Ala-His-Met-Lys-NH(2) by Edman degradation and ESI-QTOF mass spectrometry. Synthetic melectin exhibited antimicrobial activity against both gram-positive and -negative bacteria and it degranulated rat peritoneal mast cells, but its hemolytic activity was low. The CD spectra of melectin measured in the presence of trifluoroethanol and sodium dodecyl sulfate showed a high content alpha-helices, which indicates that melectin can adopt an amphipathic alpha-helical secondary structure in an anisotropic environment such as the bacterial cell membrane. To envisage the role of the proline residue located in the middle of the peptide chain on biological activity and secondary structure, we prepared several melectin analogues in which the Pro11 residue was either replaced by other amino acid residues or was omitted. The results of biological testing suggest that a Pro kink in the alpha-helical structure of melectin plays an important role in selectivity for bacterial cells. In addition, a series of N- and C-terminal-shortened analogues was synthesized to examine which region of the peptide is related to antimicrobial activity.