LiF enhanced nucleation of the low temperature microcrystalline silicon prepared by plasma enhanced chemical vapour deposition

A 15-nm lithium fluoride (LiF) thin film evaporated on glass substrate is shown to enhance the nucleation of microcrystalline Si grown by plasma enhanced chemical vapour deposition at the amorphous/microcrystalline boundary conditions. The effect is more pronounced at low substrate temperatures, nucleation density being 10 times higher at ∼ 80 °C. The effect is ascribed to the ionic chemical nature of LiF, the low work function material used in organic electronic devices, and we propose its use for micro patterning crystalline Si regions in otherwise amorphous Si film.     

Compressive creep of Fe3Al-type iron aluminide with Zr additions

High-temperature creep of a Fe₃Al-type iron aluminide alloyed by zirconium was studied in the temperature range 873–1073 K. The alloy contained (wt.%) 31.5% Al, 3.5% Cr, 0.25% Zr, 0.19% C (Fe balance). It was tested in two states: (i) as received after hot rolling and (ii) heat treated (1423 K/2 h/air). Creep tests were performed in compression at constant load with stepwise loading: in each step, the load was changed to a new value after steady state creep rate had been established. Stress exponent and activation energy of the creep rate were determined and possible creep mechanisms were discussed in terms of the threshold stress concept. A rapid fall of the stress exponent and of the threshold stress with the increasing temperature indicates that creep is impeded by the presence of precipitates only at temperature 873 K. The results were compared with the results of long-term creep tests in tension performed recently on the same alloy. __________ Translated from Problemy Prochnosti, No. 1, pp. 117–120, January–February, 2008.     

Fuzzy model for the prediction of unconfined compressive strength of rock samples

A data driven approach to the modeling of unconfined compressive strength of rock samples is presented. Fuzzy logic approach is used to represent a nonlinear relationship as a smooth concatenation of local linear submodels. The partitioning of the input space into fuzzy regions, represented by the individual rules, is obtained through fuzzy clustering. The numerical results are compared with a conventional statistical (multi-linear) model. It is shown that the fuzzy model is not only more accurate but as opposed to other black-box approaches (such as neural networks), it also provides some insight into the nonlinear relationship represented by the model.     

Edible mushroom (Agaricus bisporus) lectin, which reversibly inhibits epithelial cell proliferation, blocks nuclear localization sequence-dependent nuclear protein import

The Galbeta1-3GalNAcalpha (TF antigen)-binding lectin (ABL) from the common edible mushroom (Agaricus bisporus) has a potent anti-proliferative effect without any apparent cytotoxicity. This unusual combination of properties prompted investigation of its mechanism of action. In contrast to soluble lectin, agarose-immobilized, and hence noninternalizable ABL had no effect on proliferation of HT29 colon cancer cells. Electron microscopy of HT29 cells incubated with fluorescein- and gold-conjugated ABL showed internalization of the lectin into endocytotic vesicles and multivesicular bodies. Confocal microscopy showed perinuclear accumulation of fluorescein isothiocyanate-conjugated lectin, which also inhibits HT29 cell proliferation, raising the possibility that the lectin might interfere with nuclear pore function. Transport of heat shock protein 70 into the nucleus in response to heat shock was blocked by preincubation of HT29 cells for 6 h with 40 micrograms/ml ABL. In digitonin-permeabilized cells, nuclear uptake of bovine albumin conjugated to a nuclear localization sequence (NLS)-containing peptide was also inhibited by a 15-min preincubation with 40-100 micrograms/ml ABL. In contrast, serum-stimulated nuclear translocation of mitogen-activated protein kinase, which is NLS-independent, was not affected by pretreatment of cells with the lectin. These results suggest that the anti-proliferative effect of ABL is likely to be a consequence of the lectin trafficking to the nuclear periphery, where it blocks NLS-dependent protein uptake into the nucleus.     

Examination of the Polymorphism of Piroxicam in Connection with the Preparation of a New “Soft-Patch” Type Pharmaceutical Dosage Form

The influence of different solvents (propylene glycol, glycerol, ethanol), as well as different technological procedures (melting, rapid and slow cooling), on the formation of polymorphous piroxicam modifications was examined in the course of the elaboration of a “soft-patch” type of semisolid pharmaceutical dosage form. The thermodynamical behavior, some physicochemical properties (such as melting point, dissolution rate), and infrared (IR) spectrum of the formed (needle and cubic) crystal modifications were studied, and the possibilities of their formation and their avoidance were examined.     

Antifungal activity of lauric acid derivatives against Aspergillus niger

The antifungal effects of lauric acid and four lauric acid derivatives (monolauroylglycerol, D-laurate A, T-laurate A, 6-O-lauroysucrose) were tested on the spore germination and the growth rate of Aspergillus niger DMF 0801. The results showed that the tested substances varied in their antifungal activity and they also confirmed the relation of the structure of tested substances and their antifungal effects. Monolauroylglycerol at concentration level between 0.2 and 1.8 mmol l^-1 caused the highest inhibition of spore outgrowths whereas 6-O-lauroysucrose at concentration between 0.05 and 1.8 mmol l^-1 did not exhibit inhibition of spore germination. The inhibition of colony growth rate was detected mainly at presence of 6-O-lauroysucrose.     

Mixing of solids in different mixing devices

Mixing of powders is a common operation in any industry. Most powders are known to be cohesive, many agglomerate spontaneously when exposed to humid atmosphere or elevated storage temperature. Agitation of the powder (especially powders with different bulk densities) may result in migration of smaller particles downwards and of larger ones upwards. Another problem is segregation whose main cause is the difference in particle size, density shape and resilience. There are standard mixing devices, such as drum tumblers or Turbula mixers. Alternate device type used is the static mixer of Kenics type. Static mixers save energy, disable segregation and effect particle migration. In this paper, static mixers, as devices for powder mixing, are tested as well as Turbula and V-shaped drum mixer, since those devices are commonly used for powder blending in industry. Mixtures that were blended by means of those three devices were made out of the model material, quartz sand, in different component ratios (20:80 and 30:70). The results were statistically calculated and graphically presented. Cohesion indexes were measured with Powder Flow Analyser to see the effect of material flow on the mixture quality. The results obtained by those three devices, the particle size effect and cohesion indexes, bring us to the conclusion that static mixers could be used for mixing of powders, but their shape, number of mixing elements and the mixer length should be adapted for each mixture separately, experimentally and mathematically, through modelling of the system.     

Genetic-demographic processes in urban populations of the Ukraine in the 1990's. Marriage structure of the Kharkov population

The characteristics of marriages contracted in 1993 in two districts of the city of Khar'kov were studied. The age, education, occupation, ethnicity, and birthplace of the spouses were recorded. The genetic demographic parameters of the marriage structure were compared to the results of a similar study performed in 1985. It was found that since 1985, the average age of marriage and the educational level of spouses had increased, while the ethnic diversity and coefficients of contingency by the spouses' ethnicity and profession had decreased. The contingency coefficient for the birthplace has increased. The causes and genetic consequences of these changes are discussed.     

Distribution of T-bands and telomeric (TTAGGG)n nucleotide repeats on chromosomes of Bos taurus

Distribution of T-bands on mitotic chromosomes of Bos taurus was studied. Association of T-bands with telomeres and enrichment of T-bands with genes, with a known localization is described. After THA-banding on the chromosomes of cattle, telomeric and pericentromeric regions of all autosomes showed bright fluorescence. The exception was for chromosome 7, which did not have telomeric T-bands. Interstitial T-bands were detected only on chromosomes 7, 16, and Y (7q13, 7q15, 7q22, 7q24, 16q21, and Yp12). A total proportion of centromeric, telomeric, and interstitial T-bands was 11.19, 9.97, and 2.02% of the length of the haploid chromosome set, respectively. By means of fluorescent in situ hybridization (FISH), the presence of the telomeric repeat (TTAGGG)n was shown not only in telomeric regions of all autosome, but also in all pericentromeric regions. The obtained data are indicative of the specificity of T-banding on the chromosomes of Bos taurus.