Analyse des Thermalwassers der Stadt Szeged

Ohne Zusammenfassung     

Metamaterials with negative compressibility — a novel concept with a long history

Metamaterials with negative compressibility are a very promising group of novel materials with a wide variety of potential application. A recent model proposed construction of the structures with three-dimensional negative compressibility by utilizing successive destabilization of stable or metastable states and inducing phase transitions mimicking negative compressibility. Here, we would like to show that similar concept is used by the nature and a nice example of this kind of metamaterial can be seen even in a glass of water.     

Effect of metal ions on corrosion inhibition of pimeloyl-1,5-di-hydroxamic acid for steel in neutral solution

The influence of metal ions on the adsorption process and corrosion inhibition of pimeloyl-1,5-di-hydroxamic acid (C7) on carbon steel surface in neutral solutions has been investigated by surface analytical and electrochemical techniques. Effective corrosion inhibition given by C7 in the presence of Zn²⁺ and Ni²⁺ is believed to be associated with the ability of the hydroxamic acid to form stable slightly soluble complexes with these cations. The influence of the metal ions on the inhibition efficiency is primarily related to the stability constants of C7-cation complexes. Magnesium has no effect on the inhibition performance as it has low stability constant with C7. It was found that the inhibition by C7/cation mixtures depends greatly on the molar ratio and immersion time.     

Synthesis of trans-4,5-epoxy-(E)-2-decenal and its deuterated analog used for the development of a sensitive and selective quantification method based on isotope dilution assay with negative chemical ionization

The volatile compound trans-4,5-epoxy-(E)-2-decenal (1) was synthesized in two steps with good overall yields. The newly developed method is based on trans-epoxidation of (F)-2-octenal with alkaline hydrogen peroxide followed by a Wittig-type chain elongation with the ylide formylmethylene triphenylphosphorane. For the synthesis of [4,5-²H₂]-trans-4,5-epoxy-(E)-2-decenal (d-1), [2,3-²H₂]-(E)-2-octenal was prepared by reduction of 2-octyn-1-ol with lithium aluminum deuteride and subsequent oxidation of [2,3-²H₂]-(E)-2-octen-1-ol with manganese oxide. Compound d-1 was used as internal standard for the quantification of 1 by isotope dilution assay. Among various mass spectrometry (MS) ionization techniques tested, negative chemical ionization with ammonia as reagent gas gave best results with respect to both sensitivity and selectivity. The detection limit was found to be at about 1 pg of the analyte introduced into the gas chromatography-MS system.     

Eliminating Cycles in the Discrete Torus

In this paper we consider the following question: how many vertices of the discrete torus must be deleted so that no topologically nontrivial cycles remain?We look at two different edge structures for the discrete torus. For (? _m ^d )₁, where two vertices in ? _m are connected if their ? ₁ distance is 1, we show a nontrivial upper bound of \(d^{\log_{2}(3/2)}m^{d-1}\approx d^{0.6}m^{d-1}\) on the number of vertices that must be deleted. For (? _m ^d )_∞, where two vertices are connected if their ? _∞ distance is 1, Saks et al. (Combinatorica 24(3):525–530, 2004) already gave a nearly tight lower bound of d(m?1) ^d?1 using arguments involving linear algebra. We give a more elementary proof which improves the bound to m ^d ?(m?1) ^d , which is precisely tight.     

Observation of the radiative transitions between 4d9(2D5/2,3/2)5s2nl and 4d105p(2P

Radiative transitions between the 4d ⁹(² D _5/2,3/2)⁵ s ² nl and 4d ¹⁰5p(² P ₁ ^2,3/2/0 )nl autoionization states of the cadmium atom, representing dielectronic recombination satellites of the laser lines of Cd⁺ ion with λ = 325.0 nm (4d ⁹5s ^{2 2} D _3/2 → 4d ¹⁰5p ² P ₁ ^2/0 ) and λ = 353.6 nm (4d ⁹5s ^{2 2} D _3/2 → 4d ¹⁰5p ² P ₃ ^2/0 ), have been observed for the first time in the regime of electron-ion collisions. The energy dependence of the effective cross sections for the electron-impact excitation of satellite lines has been studied in the interval from 7 to 10 eV. The effective cross sections for the excitation of dielectronic recombination satellites are on the order of ∼10⁻¹⁷ cm², which is comparable with the efficiency of excitation of the main laser lines.     

Calibration of Fluxset sensors for the measurement of spatially strongly inhomogeneous magnetic fields

A procedure developed for the calibration of a magnetic sensor in spatially strongly inhomogeneous magnetic field is presented in this paper. Assuming that the sensor is linear and it does not significantly disturb the magnetic field to be measured, its output signal is approximated as the weighted sum of the field values calculated theoretically around the sensor. The weighting coefficients are obtained by finding the best fit of the actual experimental output and the theoretical prediction of the measured field in the least square sense. Using the presented procedure, sensors can be calibrated for the measurement of spatially strongly inhomogeneous magnetic fields, consequently such sensors can be applied to get the field distribution map of inhomogeneous fields.     

Rescue of Vasopressin Synthesis in Magnocellular Neurons of the Supraoptic Nucleus Normalises Acute Stress-Induced Adrenocorticotropin Secretion and Unmasks an Effect on Social Behaviour in Male Vasopressin-Deficient Brattleboro Rats

The relevance of vasopressin (AVP) of magnocellular origin to the regulation of the endocrine stress axis and related behaviour is still under discussion. We aimed to obtain deeper insight into this process. To rescue magnocellular AVP synthesis, a vasopressin-containing adeno-associated virus vector (AVP-AAV) was injected into the supraoptic nucleus (SON) of AVP-deficient Brattleboro rats (di/di). We compared +/+, di/di, and AVP-AAV treated di/di male rats. The AVP-AAV treatment rescued the AVP synthesis in the SON both morphologically and functionally. It also rescued the peak of adrenocorticotropin release triggered by immune and metabolic challenges without affecting corticosterone levels. The elevated corticotropin-releasing hormone receptor 1 mRNA levels in the anterior pituitary of di/di-rats were diminished by the AVP-AAV-treatment. The altered c-Fos synthesis in di/di-rats in response to a metabolic stressor was normalised by AVP-AAV in both the SON and medial amygdala (MeA), but not in the central and basolateral amygdala or lateral hypothalamus. In vitro electrophysiological recordings showed an AVP-induced inhibition of MeA neurons that was prevented by picrotoxin administration, supporting the possible regulatory role of AVP originating in the SON. A memory deficit in the novel object recognition test seen in di/di animals remained unaffected by AVP-AAV treatment. Interestingly, although di/di rats show intact social investigation and aggression, the SON AVP-AAV treatment resulted in an alteration of these social behaviours. AVP released from the magnocellular SON neurons may stimulate adrenocorticotropin secretion in response to defined stressors and might participate in the fine-tuning of social behaviour with a possible contribution from the MeA.     

Synthesis of Sucrose-HDI Cooligomers: New Polyols for Novel Polyurethane Networks

Sucrose-1,6-hexamethylene diisocyanate (HDI) cooligomers were synthesized and used as new polyols for poly(ε-caprolactone) (PCL)-based polyurethanes. The polyaddition reaction of sucrose and HDI was monitored by MALDI-TOF MS. It was found that by selecting appropriate reaction conditions, mostly linear oligomer chains containing 16 sucrose units could be obtained. For the synthesis of polyurethane networks, prepolymers were prepared by the reaction of poly(ε-caprolactone) (PCL, 10 kg/mol) with HDI or 4,4′-methylene diphenyl diisocyanate (MDI) and were reacted with sucrose-HDI cooligomers. The so-obtained sucrose-containing polyurethanes were characterized by means of attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FT IR), swelling, mechanical (uniaxial tensile tests) and differential scanning calorimetry (DSC).