Untersuchungen zum Zusammenhang von Prolaktin und Dehydroepiandrosteron-sulfat bei Hypophysenpatienten

In dieser retrospektive Studie wurden 87 Patienten (UMR, UKD) mit einem Prolaktinom ausgewertet. Dabei fand ich heraus, dass Prolaktin signifikant mit DHEAS korreliert. Dies geschieht bei beiden Geschlechtern, unabhängig vom BMI und kaum beeinflusst vom Alter. Grund dafür könnte eine direkte Wirkung von Prolaktin auf die NNR sein. Bei Patienten mit intakter HVL-Funktion und/oder Mikroprolaktinom lässt sich ein größerer rs errechnen. Auch bleibt die Korrelation, wenn die PRL-Spiegel therapiebedingt nicht erhöht sind. Zwischen DHEAS und IGF1 besteht jediglich eine altersabhängige Scheinkorrelation

Can CabECO® technology be used for the disinfection of highly faecal-polluted surface water?

In this work, the disinfection of highly faecal-polluted surface water was studied using a new electrochemical cell (CabECO® cell, manufactured by CONDIAS) specifically designed to produce ozone in water with very low conductivity. The disinfection tests were carried out in a discontinuous mode to evaluate the influence of the electrode current charge passed. The effect of the current density was also studied in order to optimize the disinfection conditions and to simultaneously prevent the formation of undesirable by-products (chlorates and perchlorates) during the electrolysis. The results demonstrate that this technology is robust and efficient, and it can suitably disinfect water. During electrolysis, the chloride contained in the water was oxidized to hypochlorite, and this compound was combined with ammonia to form chloramines. Both hypochlorite and chloramines (formed by the well-known break point reaction) promoted persistent disinfection and seemed to be mainly responsible for the disinfection attained during the electrochemical process. Chlorate and perchlorate could also be produced, although the low concentrations of chloride in the tested water made them irrelevant. The removal of the total organic carbon under the applied operating conditions was not very efficient (although it reached 50% in 2 h) and the production of trihalomethanes was very low, below 100 ppb for all tests

Electro-disinfection with BDD-electrodes featuring PEM technology

This work reports the use of a special PEM-electrolyzer equipped with diamond anodes for the highly-efficient disinfection of water preventing the formation of chlorates and perchlorates. The cell is a MIKROZON® cell manufactured by CONDIAS (Itzehoe, Germany) with a very short hydraulic residence time (0.008 s for 90 L h−1, which is the maximum allowable flowrate) and a polymer exchange membrane electrolyte that separates the anode and cathode into a membrane-electrode assembly. This cell can avoid the formation of significant concentrations of chlorates because of the very short contact time between the water and the electrode that prevents the oxidation of hypochlorite by hydroxyl radicals. In this paper, we report tests in which we demonstrate this outstanding performance even in the worst conditions (low flowrate) and we also explain the differences observed in the operation in continuous and discontinuous mode with the same water

Operating the CabECO® membrane electrolytic technology in continuous mode for the direct disinfection of highly fecal-polluted water

In this work, the CabECO® electrochemical cell is evaluated in continuous mode for the disinfection of highly fecal-polluted surface water. Results show that this cell is very efficient in the removal of Total Coliforms and Pseudomonas Aeruginosa and it can achieve decays up to 4-log units when treating 90 L h−1 with a single cell (only 24 cm2 of diamond electrode). Efficiency of the disinfection depends on the current charge applied and neither organo-chlorinated species nor perchlorates are formed at the conditions evaluated. A two-log unit sterilization can be attained with the technology, which shows worse prospects for this application than for disinfection. Electrode’s fouling caused by strongly polluted water may diminish the disinfection efficiency and it can even prevent the use of this technology in those cases

Testing the use of cells equipped with solid polymer electrolytes for electro-disinfection

This work focuses on disinfection of water using electrolysis with boron doped diamond (BDD) coatings and faces this challenge by comparing the performance of two different cells manufactured by CONDIAS GmbH (Izehoe, Germany): CONDIACELL® ECWP and CabECO cells. They are both equipped with diamond electrodes, but the mechanical design is completely different, varying not only by geometry but also by the flow conditions. ECWP is a flow-through cell with perforated electrodes while the CabECO cell is a zero-gap cell with a proton exchange membrane as a solid polymer electrolyte (SPE) separating the anode and cathode. At 0.02 Ah dm−3 both cells attain around 3–5 logs pathogen removal, but design and sizing parameters give an advantage to the CabECO: it can minimize the production of chlorates and perchlorates when operating in a single-pass mode, which becomes a really remarkable point. In this paper, we report tests in which we demonstrate this outstanding performance and we also explain the differences observed in the two cells operating with the same water

Versatile Coordination of Cyclopentadienyl-Arene Ligands and Its Role in Titanium-Catalyzed Ethylene Trimerization

Cationic titanium(IV) complexes with ansa-(η5-cyclopentadienyl,η6-arene) ligands were synthesized and characterized by X-ray crystallography. The strength of the metal-arene interaction in these systems was studied by variable-temperature NMR spectroscopy. Complexes with a C1 bridge between the cyclopentadienyl and arene moieties feature hemilabile coordination behavior of the ligand and consequently are active ethylene trimerization catalysts. Reaction of the titanium(IV) dimethyl cations with CO results in conversion to the analogous cationic titanium(II) dicarbonyl species. Metal-to-ligand backdonation in these formally low-valent complexes gives rise to a strongly bonded, partially reduced arene moiety. In contrast to the η6-arene coordination mode observed for titanium, the more electron-rich vanadium(V) cations [cyclopentadienyl-arene]V(NiPr2)(NC6H4-4-Me)+ feature η1-arene binding, as determined by a crystallographic study. The three different metal-arene coordination modes that we experimentally observed model intermediates in the cycle for titanium-catalyzed ethylene trimerization. The nature of the metal-arene interaction in these systems was studied by DFT calculations.

Mechanistic Elucidation of the Arylation of Non-Spectator N-Heterocyclic Carbenes at Copper Using a Combined Experimental and Computational Approach

CuI(NHC)Br complexes (NHC = N-heterocyclic carbene) undergo a direct reaction with iodobenzene to give 2-arylated benzimidazolium products. The nature of the N-substituent on the NHC ligand influences the reactivity of the CuI(NHC)Br complex toward arylation. N-Benzyl or N-phenyl substituents facilitate arylation, whereas N-mesityl substituents hinder arylation. Density functional theory calculations show that an oxidative addition/reductive elimination pathway involving CuIII species is energetically feasible. A less hindered CuI(NHC)Br complex with N-benzyl groups is susceptible to oxidation reactions to give 1,3-dibenzylbenzimidazolium cations containing a CuIBr anion (various polymorphs). The results described herein are of relevance to C–H functionalization of (benz)azoles