Effect of post preparation on the apical seal of teeth obturated with plastic thermafil obturators

The effect of post canal preparation on the apical seal of endodontically obturated teeth with plastic Thermafil obturators was studied in vitro. Fifty-four extracted human maxillary anterior teeth were divided into four experimental and two control groups. Two groups were obturated with lateral condensation or plastic Thermafil obturator techniques; this was followed by post space preparation. Two groups were obturated as described above except that post space was not prepared. Apical leakage was determined with the use of 2% methylene blue dye solution at an absolute pressure of 75 mm Hg. There were no statistically significant differences between any of the groups. The clinical implication of these findings is discussed.     

Estimation of the amount of tropospheric ozone in a cloudy sky by ground-based Fourier-transform infrared emission spectroscopy

The problem of retrieving minor concentrations of constituents by ground-based Fourier-transform infrared emission spectroscopy is addressed by means of the concept of differential optical emission spectroscopy in analogy to the concept of differential optical absorption spectroscopy. Using the prominent nu(3) ozone feature at 1043 cm(-1), we show that the strength of the spectral signature depends not only on the amount of ozone but also on the atmospheric thermal structure. This dependence can be described by a rather accurate approximation, which was used to construct a simple diagram to estimate the amount of column ozone between the instrument site and a cloud deck as well as to determine the detection limit. The detection limit is shown to depend on cloud base height. For a given thermal lapse rate it was found that the lower the detection limit, the higher the cloud base altitude. However, as shown in a case study with variable cloud base height, the concept fails for semitransparent clouds. Multiple scattering of the emitted radiation within the clouds yielded a path enhancement that simulated an enhanced amount of constituent. The path enhancement was estimated to be 2.4-4 km at 1000 cm(-1) for low-level clouds, equivalent to an enhancement factor of 6-21. The multiple scattering effect has considerable consequences for ground-based as well as for nadir satellite retrieval techniques in cloudy skies.     

"Healthometer"--an instrument for self-distributed health screening and prevention in the population

In the ongoing expansion of medical systems toward prevention and health promotion, primary care is increasingly recognized as a key vehicle and agent. In order to establish a comprehensive health dialogue in the population, there is a need for innovative instruments corresponding to the information and linked media revolution that this shift is a part of. Based upon the experiences of the Department of Preventive Medicine in Malm?, Sweden, a self-mediated, interactive health testing and promotion instrument called "healthometer" has been developed and tested for feasibility. The instrument uses a special variety of a quintile-distributed visual analog scale with the thermometer as reference and allows: (a) easy summation and averaging of single or different aggregates of the test items as a "wellness" profile and score with emphasis upon the positive aspects of health, and (b) recognition against this on the whole favorable background of the weak points motivating further action. The instrument, which can be distributed on paper or electronic medium, supports participation and insight in the initial stages of a directed individual health program for the continuation of which the utilization of professional counsel is stimulated.     

Effect of stereoregularity and solvent upon molecular motion and structure of stereoregular poly(methyl methacrylates) in solution. 13C and 1H n.m.r. relaxation study

Spin-lattice relaxation times T₁ of ¹³C and ¹H nuclei, as well as nuclear Overhauser enhancement (NOE) values of stereoregular poly(methyl methacrylates) (PMMA) in CD₃CN and CDCl₃ were measured. Analysis of these data has shown that the mobility of PMMA in solution is affected by stereoregularity of PMMA and by solvent. Comparison of ¹³C and ¹H n.m.r. relaxation data has further shown that the solvent affects also the local conformational structure of stereoregular PMMA in solution; this conclusion is supported by preliminary measurements of infra-red spectra. Based on this finding, the effect of solvent upon formation of the ordered structure of the so-called stereocomplex of PMMA is discussed.     

Operation of the CAPRICE electron cyclotron resonance ion source applying frequency tuning and double frequency heating

The properties of the electromagnetic waves heating the electrons of the ECR ion sources (ECRIS) plasma affect the features of the extracted ion beams such as the emittance, the shape, and the current, in particular for higher charge states. The electron heating methods such as the frequency tuning effect and the double frequency heating are widely used for enhancing the performances of ECRIS or even for the routine operation during the beam production. In order to better investigate these effects the CAPRICE ECRIS has been operated using these techniques. The ion beam properties for highly charged ions have been measured with beam diagnostic tools. The reason of the observed variations of this performance can be related to the different electromagnetic field patterns, which are changing inside the plasma chamber when the frequency is varying.     

Flächendatenbank für die hydrogeologische Karte im bayerischen Bodeninformationssystem

The hydrogeological survey of Bavaria has recently been intensified in order to produce a countrywide hydrogeological map at the scale of 1:50,000 by 2015. The spatial data will be seamfree, reflect the 3D-character of hydrogeological maps and comprehensive search functions will be available for the whole dataset. A spatial database was designed which incorporates the complex relations of rock and groundwater bodies. The underlying relational data model integrates the following main object types: propagation of the upper aquifers and surface layers, rock bodies, structural surfaces together with point data and fault lines, groundwater bodies as well as groundwater surfaces together with point data and the distribution of different types of groundwater potential. The database was developed as an ArcGISextension using the Geodatabase as a relational database. The application of this system supports the mapping process and guarantees a consistent data structure. After integration into the Bavarian Soil Information System, the hydrogeological spatial data will be available for the users in a searchable format.     

Tensile and fatigue behaviour of wrought magnesium alloys AZ31 and AZ61

The mechanical behaviour of two hot rolled magnesium alloys, namely the AZ31 and AZ61, has been evaluated experimentally under both monotonic and cyclic loading. Both longitudinal (L) and long transverse (LT) directions were evaluated. The tensile behaviour of the L and LT directions is similar and differs only in the offset 0.2% yield strength for both materials. This difference is attributed to the angular spread of basal poles toward the rolling direction and is more pronounced for the case of AZ31. A distinct hardening response is obvious in both directions. Twinning formation was observed; it is more pronounced in the longitudinal direction while the fracture mode is intergranular and equiaxed facets are present in the fracture surfaces of the specimens. The S–N curves exhibit a smooth transition from the low to high cycle fatigue regime. AZ61 exhibits an overall better fatigue behaviour compared to AZ31. A transgranular crack initiation mode is observed in all tested specimens while the propagation of the cracks is characterized as intergranular.     

Amperometric response from the glycolytic versus the pentose phosphate pathway in Saccharomyces cerevisiae cells

The two main metabolic pathways involved in sugar metabolism, i.e., the pentose phosphate pathway (PPP) and the glycolytic pathway (GP), were amperometrically monitored using a double-mediator system composed of menadione and ferricyanide. With the use of the Saccharomyces cerevisiae deletion mutant, EBY44, lacking the gene encoding for the branch point enzyme phosphoglucose isomerize, selective amperometric monitoring of the PPP, mainly producing NADPH, and the GP, mainly producing NADH, could be achieved. It was found that the bioelectrocatalytic current was primarily originating from NADPH. This conclusion was supported by metabolite flux analysis, confirming that, in the presence of menadione, the cells increase the rate of NADPH-producing reactions although these processes might be detrimental to cell survival. The higher rate of in vivo NADPH-dependent menadione reduction can be ascribed to the fact that the intracellular NADPH/NADP(+) ratio is much higher than NADH/NAD(+) as well as that the former ratio is more tightly controlled. This tight control over the cofactor ratios is lost upon cell disintegration as observed from spectrophotometric assays using crude cell extract, and amperometric investigations of permeabilized cells indicate a higher rate of NADH- than NADPH-dependent menadione reduction. These in vitro experiments show a higher activity of NADH-dependent than NADPH-dependent menadione-reducing dehydrogenases in S. cerevisiae cells.