Neue elektrische Quantenmaße mit weltweiter Gültigkeit ab 01. 01. 1990

New Electrical Quantum Measures with Worldwide Validity after 01. 01. 1990 After 01. 01. 1990, new and uniform quantum measures will be internationally valid for maintaining and disseminating the units of electrical voltage, the volt, and of electrical resistance, the ohm. This means that the Josephson voltage standard and the von-Klitzing Standard will finally supersede the highest-order standards of classical physics. The paper describes the new situation and discusses the advantages and disadvantages of quantum measures, their relation to the fundamental constants and the International System of Units.     

Measurements of the polarization of protons from deuteron photodisintegration for photon energies between 282 and 405 MeV

The polarization of protons from deuteron photodisintegration has been measured at the proton lab. angles 60° and 80° for photon energies between 282 and 405 MeV. Carbon was taken as analyzer. The asymmetry was observed with optical spark chambers. The effective analyzing power of the experimental arrangement has been determined by a Monte-Carlo-calculation. For the proton lab. angel 60° the polarization increases from ?0.16 (Basel convention) at a photon energy of 282 MeV to ?0.51 at 405 MeV.     

Three-dimensional snow images by MR microscopy

MR microscopy technique was introduced to visualize and quantify the three-dimensional structure of snowpack. Since the NMR signal from the ice was week, we looked at the air space instead filling with dodecane or aniline doped with iron acetylacetonate. Four types of snow were tested: ice spheres, large rounded poly crystals, small rounded mono-crystals and depth hoar crystals. A specific specimen-cooling system was developed to keep the temperature below 0 degrees C. In the experiments 0.5 to 2 h were necessary to accumulate the signals enough to obtain a 3D micro-image; the image matrix 128(3), voxel size (200 microm)3 or 256(3) (120 microm)3. Comparison with the 2D data using the conventional section plane method was also carried out and MR microscopy is proved to be a very useful method to visualize the microstructure of snowpack.     

Constructing isothermal curvature line coordinates on surfaces which admit them

Isothermic parameterizations are synonyms of isothermal curvature line parameterizations, for surfaces immersed in Euclidean spaces. We provide a method of constructing isothermic coordinate charts on surfaces which admit them, starting from an arbitrary chart. One of the primary applications of this work consists of numerical algorithms for surface visualization.     

A fitting procedure for palaeodose from old sandstone using IRSL

In the dating studies of old samples using the Infrared Stimulated Luminescence (IRSL), the validity of the curve-fitting employed is of critical importance. So, in this study, a new fitting procedure was suggested for obtaining the age of the old geological sample. IRSL technique was applied using multiple-aliquot procedure to feldspar isolated from sample. The paleodose results obtained, using linear and polynomial fitting, were (67.98±2) Gy, (30.49±2) Gy and 322.03 Gy from the suggested fitting procedure. After application of this procedure the age was found to be 551.4 ka. This work was supported by Karaelmas University under the project numbered 98-101-009-01.     

Surprising Magnetic Behavior of Cobalt(II) Ion in Recently Prepared Macrocycle Complexes. Distortion <Emphasis Type="BoldItalic">versus</Emphasis> Intermolecular Antiferromagnetic Exchange Interactions

The magnetic moment of the Co²⁺ ion in the newly reported macrocycle complex is analysed for various situations. It is realized that in order to obtain the observed magnetic moment, either some irrelevant parameters or some intermolecular antiferromagnetic interactions must be included in the magnetic Hamiltonian. It is suggested that the complex behaves as a largely distorted octahedron.     

Trabecular bone volume fraction measurements of a large number of subjects using a compact MRI

Trabecular bone volume fraction (TBVF) and speed of sound (SOS) were measured for the right calcanei of 416 female volunteers. The TBVF was measured with a compact MRI developed in our laboratory. The SOS was measured with a commercial quantitative ultrasound system. It was observed that the correlation coefficient between TBVF and SOS and that between TBVF and age varied depending on the location of region of interest (ROI) in the calcaneus. As a result, an optimum circular ROI with a diameter of 20 mm was determined so that the correlation coefficients were maximized. In the optimum ROI, transverse relaxation time (T₂) of the bone marrow protons of the calcaneus was found to be concentrated in a narrow range over the subjects. This result suggested that a 50% scan time reduction in the TBVF measurements could be made by skipping the T₂ correction procedure.     

Novel CeO2–CuO-decorated enzymatic lactate biosensors operating in low oxygen environments

The detection of the lactate level in blood plays a key role in diagnosis of some pathological conditions including cardiogenic or endotoxic shocks, respiratory failure, liver disease, systemic disorders, renal failure, and tissue hypoxia. Here, we described for the first time the use of a novel mixed metal oxide solution system to address the oxygen dependence challenge of first generation amperometric lactate biosensors. The biosensors were constructed using ceria-copper oxide (CeO₂–CuO) mixed metal oxide nanoparticles for lactate oxidase immobilization and as electrode material. The oxygen storage capacity (OSC, 492 μmol-O₂/g) of these metal oxides has the potential to reduce the oxygen dependency, and thus eliminate false results originated from the fluctuations in the oxygen concentration. In an effort to compare the performance of our novel sensor design, ceria nanoparticle decorated lactate sensors were also constructed. The enzymatic activity of the sensors were tested in oxygen-rich and oxygen-lean solutions. Our results showed that the OSC of the electrode material has a big influence on the activity of the biosensors in oxygen-lean environments. While the CeO₂ containing biosensor showed an almost 21% decrease in the sensitivity in a O₂-depleted solution, the CeO₂–CuO containing electrode, with a higher OSC value, experienced no drop in sensitivity when moving from oxygen-rich to oxygen-lean conditions. The CeO₂–CuO decorated sensor showed a high sensitivity (89.3 ± 4 μA mM⁻¹ cm⁻²), a wide linear range up to 0.6 mM, and a low limit of detection of 3.3 μM. The analytical response of the CeO₂–CuO decorated sensors was studied by detecting lactate in human serum with good selectivity and reliability. The results revealed that CeO₂–CuO containing sensors are promising candidates for continuous lactate detection.     

Half-sandwich ruthenium(II) complexes containing 4-substituted aniline derivatives: structural characterizations and catalytic properties in transfer hydrogenation of ketones

Transition Metal Chemistry - Four half-sandwich Ru(II) complexes (1)–(4) with the general formulae [Ru(η6-p-cymene)(L)Cl2] were synthesized by the reaction of one equivalent of the...     

Hormone and microorganism treatments in the cultivation of saffron (Crocus sativus L.) plants

The difficult cultivation of the saffron plant (Crocus Sativus L.) make the spice of the same name made from its dried stigmas very valuable. It is estimated that some 75,000 blossoms or 225,000 hand-picked stigmas are required to make a single pound of saffron, which explains why it is the world's most expensive spice. The aim of this study was to identify ways of increasing the fertility and production of saffron. For this purpose, the treatment of saffron bulbs with a synthetic growth hormone--a mixture of Polystimulins A6 and K--and two different microorganism based materials--biohumus or vermicompost and Effective Microorganisms (EM)--in four different ways (hormone alone, biohumus alone, EM alone and EM+biohumus) was investigated to determine whether these treatments have any statistically meaningful effects on corms and stigmas. It has been shown that EM + biohumus was the most effective choice for improved saffron cultivation.