Use of 201Thallium brain SPECT, image registration, and semi-quantitative analysis in the follow-up of brain tumors

BACKGROUND: Vasodilator drugs are increasingly being discussed as possible antiglaucomatous substances. Aim of the present study is to evaluate, from a hemodynamic point of view, the vasodilator drug isosorbide dinitrate (ISDN) regarding its suitability for glaucoma therapy. METHODS: 20 healthy subjects (mean age: 28 yrs) volunteered to participate in the study. In randomized order, each subject received one tablet containing 40 mg ISDN (sequels) or--in a second trial--one tablet placebo (+500 mg of the analgetic metamizol, respectively, for prophylaxis of nitrate headache). 1 h before as well as 1, 3, 5, and 7 hrs after medication, the following variables were determined using oculo-oscillo-dynamography: systolic ophthalmic artery pressure (SOAP), systolic ocular perfusion pressure (SOPP), ocular pulsation amplitude (OPA) and the product OPA x heart rate (HR). Intraocular pressure (IOP) as well as systolic and diastolic brachial artery pressures (SBAP, DBAP) were also measured. RESULTS: After administration of ISDN (+analgetic), the variables SBAP, SOAP and SOPP were significantly (p = 0.01) lowered compared to placebo (+analgetic), and also the IOP tended to be lower (p = 0.08). The maximum reduction was found 3-5 hrs after medication: SBAP 10.9 mm Hg (9%), SOAP 12.5 mm Hg (14%), SOPP 11.3 mm Hg (14.5%), and IOP 1.5 mm Hg (12%). The relation SOAP vs. SBAP was significantly (p = 0.0004) linear, the correlation coefficient amounted to 0.39. DBAP remained unchanged, HR was increased by 4-7 beats/min (p = 0.08). OPA and the product OPA x HR showed highly significant decreases by maximum values of 44% and 40%, respectively. CONCLUSION: ISDN (+analgetic) caused a reduction of SOAP and SOPP, which can be accounted for by the reduced systolic systemic blood pressure. In addition, there was a decrease of OPA and of the product OPA x HR (a measure of pulsatile ocular blood flow), which finding may be explained by a cardiac stroke volume reduction that is typical for nitrates. Due to these hemodynamic effects and due to the only weak IOP reduction, ISDN does not appear to be suitable for glaucoma therapy.     

Theoretical evaluation of the shape of the deformation zone in the press piercing mill

An analysis of metal deformation in the press piercing mill is presented in the paper. Interpenetration of the groove surface and billet surface was the base of the theoretical solution. Bulging of the material in front of the deformation zone was taken into consideration. The analysis resulted in the determination of strains within the deformation zone. Equations which describe the billet surface were derived and the contact interface was determined.     

Bronchial asthma: do boys or girls have the highest incidence?

The aim of the study was to assess the gender related prevalence of asthma and asthma symptoms in schoolchildren. The survey was performed using standardized ISAAC questionnaire in two age groups: 6-7 yr. (n = 2281; girls 49.7%) and 13-14 yr. (n = 4849; girls 49.8%). It was revealed that in older group the prevalence of ever diagnosed asthma was lower in girls than in boys (2.0% versus 3.3%; odds ratio [OR] = 0.58; p = 0.004). But the prevalence of symptoms: wheeze ever (OR = 1.16; p = 0.056), current wheeze (last 12 mo) (OR = 1.26; p = 0.029), current exercise wheeze (OR = 1.40; p = 0.0008), current night cough (OR = 1.67; p = 0.0001) were higher in girls than in boys. However, in younger group of schoolchildren the prevalence of ever diagnosed asthma and asthma symptoms were higher in boys (5.1% male versus 3.5% female). The girls in comparison to boys revealed lower risk of ever asthma diagnosis (OR = 0.66; p = 0.056) and symptoms: wheeze ever (OR = 0.63; p = 0.0001), current wheeze (OR = 0.69; p = 0.003), current exercise wheeze (OR = 0.59; p = 0.008) and current night cough (OR = 0.70; p = 0.0003).     

Simulation of metal flow and heat transfer during hot rolling of bimetal plates

Coupled thermomechanical finite element model is applied to simulate metal flow and temperature distribution during hot rolling of bimetal plates. Calculations are carried out for various reductions and dimensions of the plates. Two possible versions of the boundary conditions are assumed. The first considers the case when special guides or tensions prevent bending of the sample before entering and after exit from the roll gap. The second allows free bending of the plate on both sides of the mill. Results of calculations include distributions of strain rates, strains, roll pressure, friction forces and temperatures during rolling. Calculated rolling force and torque are compared with the experimental data. Several conclusions regarding the metal flow and heat transfer in various rolling conditions are drawn.     

Validation of Multi‐scale Model Describing Microstructure Evolution in Steels

Properties of deformed steels depend on various microstructure parameters such as distribution of grain size and precipitates. Strain, strain rate and temperature inhomogeneities make quantitative prediction of microstructure difficult but the Finite Element method is able to model these inhomogeneities. Different scales of phenomena occurring in deformed materials are another difficulty in modelling. Microstructure evolution can be described by more realistic methods (e.g. Cellular Automata CA, Monte Carlo), which, on the other hand, are unable to simulate larger samples. Therefore, development of the methods capable of spanning multiple scales became a current challenge. CAFE modelling, which couples FE and CA methods, is the objective of the paper. The model consists of two layers. The micro‐scale layer, simulated by CA, represents microstructure evolution including nucleation and growth of the grains. Evolution of a dislocation density is described for every grain separately by solving differential equation. The FE thermal‐mechanical model is used as a macro‐scale part. Multistage plane strain compression tests for niobium steel are considered. Distributions of initial and final grain size are measured during the tests. The results from the CAFE model are compared to the measurements and to the predictions by a conventional model. The comparisons confirm the capability of the CAFE method to predict flow stress, recrystallized fraction and grain size distribution. Conventional approach gives a good agreement with experiments for an average grain size only.     

From High Accuracy to High Efficiency in Simulations of Processing of Dual-Phase Steels

Searching for a compromise between computing costs and predictive capabilities of metal processing models is the objective of this work. The justification of using multiscale and simplified models in simulations of manufacturing of DP steel products is discussed. Multiscale techniques are described and their applications to modeling annealing and stamping are shown. This approach is costly and should be used in specific applications only. Models based on the JMAK equation are an alternative. Physical simulations of the continuous annealing were conducted for validation of the models. An analysis of the computing time and predictive capabilities of the models allowed to conclude that the modified JMAK equation gives good results as far as prediction of volume fractions after annealing is needed. Contrary, a multiscale model is needed to analyze the distributions of strains in the ferritic-martensitic microstructure. The idea of simplification of multiscale models is presented, as well.     

Supramolecular associations of poly(ketanil)s with sulfonic acid derivatives of benzenetricarboxamide via Brönsted acid–base interactions: Preparation,spectroscopic morphological and thermal investigations

Supramolecular aggregations have been obtained via ionic self-assembly of conjugated poly(ketanil)s and sulfonic acid derivatives of benzenetricarboxamides. To achieve this goal a new protonating molecule has been synthesized which is a derivative of 1,3,5-benzenetricarboxamide with sulfonic acid group at each of its ends. 1,3,5-benzenetricarboxamides of C₃ symmetry tend to form ordered supramolecular aggregations via π-stacking and this property is retained in their sulfonic acid derivative. Because of their Brönsted acid nature the new molecules can additionally associate conjugated polymers with basic centers such as poly(ketanil)s. Depending on the processing solvent used (MC or DMA) 1,3,5- the sulfonic acid derivative of benzenetricarboxamide and its associations with poly(ketanil)s form aggregations of spherullite-like or feather-like morphologies as evidenced by polarized optical microscopy and atomic force microscopy. The similarity of this supramolecular organization is also corroborated by DSC studies which in both cases show endothermic type transitions of the same origin. The supramolecular acid–base associations are semi-crystalline in nature and exhibit good mechanical properties at room temperature because of a rather low T_g, in the vicinity of 300 K. This unusual lowering of T_g by ca. 90 K as compared to the case of poly(ketanil)s in their basic form is caused by the plasticizing effect of the protonating agent. Finally polyketanil–1,3,5-benzenetricarboxamide sulfonic acid derivatives show tunable photoluminescence which depends on the solvent and SO₃H/CN molar ratio.     

Content of trichodiene and analysis of fungal volatiles (electronic nose) in wheat and triticale grain naturally infected and inoculated with Fusarium culmorum

Four groups of cereal kernels were analyzed in terms of their volatile metabolite contents using GC/MS and the electronic nose. Analyses were conducted on 36 triticale breeding lines and 22 wheat breeding lines. Grain came from field samples inoculated with Fusarium culmorum and simultaneous non-inoculated samples-controls. All sample groups contained significantly varied levels of trichodiene (TRICH), a precursor for the formation of fusarium metabolites, with approx. two times higher concentration recorded in triticale. In inoculated samples TRICH concentration for wheat was on average six times higher and for triticale eight times higher than in non-inoculated samples. In the course of analysis using the electronic nose in tested groups of grain differences were observed in the profiles of detected volatile compounds. This resulted in a statistically significant distribution of investigated samples into four objects.     

Chemisorption of C3 hydrocarbons on cobalt silica supported Fischer–Tropsch catalysts

Chemisorption of propene and propane was studied in a pulse reactor over a series of cobalt silica-supported Fischer–Tropsch catalysts. It was shown that interaction of propene with cobalt metal particles resulted in its rapid autohydrogenation. The reaction consists in a part of the propene being dehydrogenated to surface carbon and CH_x chemisorbed species; hydrogen atoms released in the course of propene dehydrogenation are then involved in hydrogenation of remaining propene molecules to propane at 323–423 K or in propene hydrogenolysis to methane and ethane at temperatures higher than 423 K. The catalyst characterization suggests that propene chemisorption over cobalt catalysts is primarily a function of the density of cobalt surface metal sites. A correlation between propene chemisorption and Fischer–Tropsch reaction rate was observed over a series of cobalt silica-supported catalysts. No propane chemisorption was observed at 323–373 K over cobalt silica-supported catalysts. Propane autohydrogenolysis was found to proceed at higher temperatures, with methane being the major product of this reaction over cobalt catalysts. Hydrogen for propane autohydrogenolysis is probably provided by adsorbed CH_x species formed via propane dehydrogenation. Propene and propane chemisorption is dramatically reduced upon the catalyst exposure to synthesis gas (H₂/CO = 2) at 323–473 K. Our results suggest that cobalt metal particles are probably completely covered by carbon monoxide molecules under the conditions similar to Fischer–Tropsch synthesis and thus, most of cobalt surface sites are not available for propene and propane chemisorption.