Chemical and isotopic characterization of the thermal fluids emerging along the North-Northeastern Greece.

Hydrochemical and isotopic characteristics of fluids from major geothermal fields of middle/low temperature in N/NE Greece are examined [basins: Strymon River (SR), Nestos River Delta (ND), Xanthi-Komotini (XK), Loutros-Feres-Soufli (LFS) and Rhodope Massif]. The geodynamic context is reflected to isotopic/chemical composition of fluids, heat flow values and elevated CO2 concentrations in emitted fluids. B and Li are derived from leaching of the geothermal systems hosting rocks. δ18OH2O, δ18OSO4, δ13CCO2 values and chemical compositions of Cl, B and Li of geothermal discharges suggest two distinct source fluids. Fluids in SR exhibit high B/Cl and Li/Cl ratios, suggesting these constituents are derived from associated magmas of intermediate composition (andesitic rocks). Geothermal discharges in LFS exhibit low B/Cl and Li/Cl ratios, implying acid (rhyolitic) magmatism. δ13CCO2 and CO2/(CO2 + 105He) ratios in the west part, suggest fluids affected by addition of volatiles released from subducted marine sediments. For the eastern systems, these ratios suggest gas encountered in systems issued from mixing of crustal and mantle-derived volatiles. Isotopic geothermometers reflect, for the same direction, equilibrium processes more (LFS, XK) or less (SR) pronounced and discriminate the geothermal field from low to middle [SR, ND (Erasmio)] and middle to high enthalpy [ND (Eratino), LFS, XK].

The peculiar size and temperature dependence of water diffusion in carbon nanotubes studied with 2D NMR diffusion-relaxation D -T 2eff spectroscopy.

It is well known that water inside hydrophobic nano-channels diffuses faster than bulk water. Recent theoretical studies have shown that this enhancement depends on the size of the hydrophobic nanochannels. However, experimental evidence of this dependence is lacking. Here, by combining two-dimensional nuclear magnetic resonance diffusion-relaxation ( D - T 2 e f f ) spectroscopy in the stray field of a superconducting magnet and molecular dynamics simulations, we analyze the size dependence of water dynamics inside Carbon Nanotubes (CNTs) of different diameters ( 1.1 - 6.0 nm), in the temperature range of 265 - 305 K. Depending on the CNT diameter, the nanotube water is shown to resolve in two or more tubular components acquiring different self-diffusion coefficients. Most notably, a favorable CNT diameter range ( 3.0 - 4.5 nm) is experimentally verified for the first time, in which water molecule dynamics at the center of the CNTs exhibits distinctly non-Arrhenius behavior, characterized by ultrafast diffusion and extraordinary fragility, a result of significant importance in the efforts to understand water behavior in hydrophobic nanochannels.

Structural, static and dynamic magnetic properties of dextran coated γ-Fe(2)O(3) nanoparticles studied by (57)Fe NMR, Mössbauer, TEM and magnetization measurements.

The structural and magnetic properties and spin dynamics of dextran coated and uncoated γ-Fe(2)O(3) (maghemite) nanoparticles have been investigated using high resolution transmission electron microscopy (HRTEM), (57)Fe nuclear magnetic resonance (NMR), Mössbauer spectroscopy and dc magnetization measurements. The HRTEM observations indicated a well-crystallized system of ellipsoid-shaped nanoparticles, with an average size of 10 nm. The combined Mössbauer and magnetic study suggested the existence of significant interparticle interactions not only in the uncoated but also in the dextran coated nanoparticle assemblies. The zero-field NMR spectra of the nanoparticles at low temperatures are very similar to those of the bulk material, indicating the same hyperfine field values at saturation in accord with the performed Mössbauer measurements. The T(2) NMR spin-spin relaxation time of the nanoparticles has also been measured as a function of temperature and found to be two orders of magnitude shorter than that of the bulk material. It is shown that the thermal fluctuations in the longitudinal magnetization of the nanoparticles in the low temperature limit may account for the shortening and the temperature dependence of the T(2) relaxation time. Thus, the low temperature NMR results are in accord with the mechanism of collective magnetic excitations, due to the precession of the magnetization around the easy direction of the magnetization at an energy minimum, a mechanism originally proposed to interpret Mössbauer experiments in magnetic nanoparticles. The effect of the surface spins on the NMR relaxation mechanisms is also discussed.

Low temperature charge and orbital textures in La0.875Sr0.125MnO3.

By using nuclear magnetic resonance techniques we show that for T<30 K the La0.875Sr0.125MnO3 compound displays a nonuniform charge distribution, comprised of two interconnected Mn ion subsystems with different spin, orbital, and charge couplings. The NMR results agree very well with the two spin wave stiffness constants observed at small q values in the spin wave dispersion curves [Phys. Rev. B 67, 214430 (2003)]. This picture is probably related to a yet undetermined charge and orbital superstructure occurring in the ferromagnetic insulating state of the La0.875Sr0.125MnO3 compound.

Purification and analysis of authentic CLIP-170 and recombinant fragments.

We have purified authentic CLIP-170 (cytoplasmic linker protein of 170 kDa) and fragments comprising functional domains of the protein to characterize the structural basis of the function of CLIP-170. Analysis of authentic CLIP-170 and the recombinant fragments by electron microscopy after glycerol spraying/low angle rotary metal shadowing reveals CLIP-170 as a thin, 135-nm-long molecule with two kinks in its central rod domain, which are approximately equally spaced from the two ends of the protein. The central domain consisting of heptad repeats, which is alpha-helical in nature and forms a 2-stranded coiled-coil, mediates dimerization of CLIP-170. The rod domain harbors two kinks, each spaced approximately 37 nm from the corresponding end of the molecule, thus providing mechanical flexibility to the highly elongated molecule. The N-terminal domain of CLIP-170 binds to microtubules in vitro with a stoichiometry of one dimeric head domain per four tubulin heterodimers. Authentic CLIP-170 binds to microtubules with lower stoichiometry, indicating that the rod and tail domains affect microtubule binding of CLIP-170. These results document that CLIP-170 is a highly elongated polar molecule with the microtubule-binding domain and the organelle-interacting domains at opposite ends of the homodimer, thus providing a structural basis for the function of CLIP-170 as a microtubule-organelle linker protein.

CLIP-170 highlights growing microtubule ends in vivo.

A chimera with the green fluorescent protein (GFP) has been constructed to visualize the dynamic properties of the endosome-microtubule linker protein CLIP170 (GFP-CLIP170). GFP-CLIP170 binds in stretches along a subset of microtubule ends. These fluorescent stretches appear to move with the growing tips of microtubules at 0.15-0.4 microm/s, comparable to microtubule elongation in vivo. Analysis of speckles along dynamic GFP-CLIP170 stretches suggests that CLIP170 treadmills on growing microtubule ends, rather than being continuously transported toward these ends. Drugs affecting microtubule dynamics rapidly inhibit movement of GFP-CLIP170 dashes. We propose that GFP-CLIP170 highlights growing microtubule ends by specifically recognizing the structure of a segment of newly polymerized tubulin.

Dynamic localization of CLIP-170 to microtubule plus ends is coupled to microtubule assembly.

CLIP-170 is a cytoplasmic linker protein that localizes to plus ends of microtubules in vivo. In this study, we have characterized the microtubule-binding properties of CLIP-170, to understand the mechanism of its plus end targeting. We show that the NH2-terminal microtubule-interacting domain of CLIP-170 alone localizes to microtubule plus ends when transfected into cells. Association of CLIP-170 with newly-formed microtubules was observed in cells microinjected with biotinylated tubulin, used as a tracer for growing microtubules. Using in vitro assays, association of CLIP-170 with recently polymerized tubulin is also seen. Cross-linking and sedimentation velocity experiments suggest association of CLIP-170 with nonpolymerized tubulin. We conclude from these experiments that the microtubule end targeting of CLIP-170 is closely linked to tubulin polymerization.

[Various metabolic effects in total parenteral feeding using a carbohydrate combination and amino-acid solution in the pre- and postoperative phase]. / Einige Stoffwechselwirkungen bei totaler parenteraler Ernährung mit einer Kohlenhydratkombinations- und Aminosäurenlösung in der prä- und postoperativen Phase.

Ten metabolically healthy patients who had undergone gastric resection were fed intravenously from the preoperative to the 5th postoperative day. After the 24-hour preoperative infusion period the concentration of cholesterol, free fatty acids and alkaline phosphatase dropped significantly. So did the concentration of uric acid. During the postoperative period cholesterol and uric acid continued to fall. The concentration of free fatty acids remained low all the postoperative days. From the second postoperative day on the triglycerides rose continuously. Serum glutamic oxalacetic transaminase and serum lactic dehydrogenase reached their highest level on the first postoperative day. On the same day the alkaline phosphatase dropped to the lowest level. Five patients had a rise of total bilirubin up to 1.1 mg/100 at the end of the infusion period.

[Metabolic behavior in pre, intra, and postoperative total parenteral feeding with a carbohydrate combination and amino acid solution]. / Stoffwechselverhalten bei prä-, intra- und postoperativer totaler parenteraler Ernährung mit einer Kohlenhydratkombinations- und Aminosäurenlösung.

Ten metabolically healthy patients who had undergone gastric resection were fed intravenously from the preoperative to the 5th postoperative day. No metabolic alternations were observed by using a low dosis of 0.12 mg/kg.h of glucose, fructose and xylitol in combination with amino acids. We were able to limit the so-called postaggressive syndrome by eliminating the fasting state. These results were proven by evaluating the most important metabolic parameters like triglycerides, free fatty acids, lactate and by measuring the carbohydrate-nitrogen balances.

[Spontaneous cholecysto-gastric fistula with massive gastrointestinal bleeding. Endoscopic diagnosis and concrement extraction]. / Spontane cholezysto-gastrische Fistel mit massiver gastrointestinaler Blutung. Endoskopische Diagnose und Konkrementextraktion

A case of spontaneous cholecysto-gastric fistula is reported with penetration of a gallstone into the stomach leading to massive haemorrhage of gastric mucosa. The gallstone was removed endoscopically, the immanent complication of gallstone ileus could be eliminated. Mucosal bleeding was stopped by conservative methods, and thus enough time was won for optimal preparation for the ensuing operation. The problems of preoperative diagnosis are mentioned, also rate and early complications of spontaneous bilio-digestive fistulae and their poor prognosis concerning the increased letality at operation.

[Coronary-angiographic demonstration of the dilating effect of dipyridamole on coronary arteries and its inhibition by caffeine (author's transl)]. / Koronarangiographischer Nachweis der Dilatation der Koronararterien durch Dipyridamol und ihre Hemmung durch Coffein

Selective coronary cineangiographies are performed repeatedly in 13 mongrel dogs. The contrast medium itself has no demonstrable dilating effect upon the vessels. After the first injection of 0.2 mg/kg of dipyridamole the left anterior coronary artery is significantly (p less than 0.001) dilated, which is in contrast to some results described in literature. Immediately after an injection of high doses of caffeine (10 mg/kg) the previously enlarged coronary diameter decreases significantly (p less than 0.001). During the action of caffeine subsequent infections of dipyridamole result in a very small, or no change in coronary diameter. The coronary-dilating effect of dipyridamole can be inhibited by high doses of caffeine (10 mg/kg).

[Electric and mechanic gastric activity under insulin, penta-gastrin, carbachol and food ingestion in the wakeful dog]. / Elektrische und mechanische Magenaktivität unter Insulin, Pentagastrin, Carbachol und Nahrungsaufnahme am wachen Hund

The effect of insulin, pentagastrin, carbachol and feeding on the electrical and mechanical activity of the stomach was examined in the conscious dog. In these experiments vagal stimulation, a gastric hormone, a parasympathetic agent and distention elecited a similar stimulation of electrical and mechanical activity. The activation occurred in case of insulin only after sufficient lowering of the blood glucose level, in case of the other tested stimulants after a few minutes.