Weighted Kolmogrov–Smirnov type tests for grouped Rayleigh data

We consider goodness of fit tests for the Rayleigh distribution with grouped data. New Kolmogrov–Smirnov type tests are suggested and compared with the traditional chi-square and likelihood ratio tests. The results show that some of the suggested tests have a good power performance as compared with the traditional ones.     

Synthesis and immunomodulatory activity of some novel amino acid germinates

Amino acid germanate compounds are synthesized by the chemical reaction of germanium dioxide with a selected amino acid in the presence of an alkali medium at a suitable elevated temperature. Amino acids included in the novel synthesis include histidine, methionine and glutathione. The study evaluated their effects on induction of interleukin-12 and interferon-γl in Swiss albino Webster rats. The new germanium compounds, especially bis-methionino germanate, are considered as good interferon inducer that significantly enhance the immunologic function.     

On the correlation between order parameter, superconducting volume fraction and critical current density in R: 123 superconductors

Resistivity and low field ac susceptibility measurements are made on R: 123 superconducting samples with different rare earth elements R. The order parameter dimensionality OPD is deduced from resistivity versus temperature plot using the Aslamazov and Larkin expression, while the analysis of the temperature dependence of ac susceptibility is done employing Beans’ critical state model and with the help of the Ravi expression. With increasing R, the critical temperatures T_c are nearly kept constant (∼90 K), while the crossover temperatures T_o are shifted to lower values. Moreover, the superconducting order parameter OPD is shifted toward 2D behavior. On the other hand, the values of superconducting volume fraction f_g decrease with increasing ac field amplitude H_m for all samples and it is higher in Er: 123 sample than in Nd: 123 sample. Although the values of critical current density J_c at the peak temperature T_m are nearly unchanged with increasing R, the values of J_c(T), at T<T_m and T>T_m, are found to be dependent on the chosen R. The correlation between the above calculated parameters against R is also mentioned.     

Studies on the scandium distribution in organs of fattened chicken by neutron activation analysis

Tissues samples of chicken /blood, liver, spleen, fat, pancreas, kidney, lung, breast muscle, brain, femur, faeces, egg yolk, white of egg/, were analyzed for scandium concentration. ScCl₃ was applied intravenously /1 mg kg^–1 body weight/. High scandium concentrations were found in the liver /34. 35 ppm/, spleen /15.46 ppm/, and lung /15.52 ppm/ three days after application. This experiment shows that accumulation of scandium occurs in the yolk of egg but not in the white of the egg.     

Barrier to internal rotation in 2,3- and 3,3-difluoropropenal and their methyl derivatives

The conformational stability and structure of 2,3-dimethylpropenal, 2,3-difluoropropenal and their 3,3-dimethyl and 3,3-difluoro derivatives were investigated utilizing ab initio calculations with 3-21G and 6-31G basis sets. For 2,3-dimethylpropenal and 3,3-difluoropropenal the s-trans was predicted to be the low-energy form. In the case of 3,3-dimethylpropenal and 2,3-difluoropropenal the s-cis was predicted by both levels of calculation to be the more stable conformer. Full optimization was performed at the transition states and the barriers to internal rotation were calculated. Methyl and fluorine substitution were found to significantly increase the barrier to interconversion in propenal. The relative change in the barrier depends on the position and the type of the substituent. The trans to cis barrier in 2,3-dimethylpropenal was calculated to be about 3 kcal mol⁻¹ greater than that in 3,3-dimethylpropenal, while the cis to trans barrier in 2,3-difluoropropenal was predicted to be about 7 kcal mol⁻¹ higher than the corresponding one in 3-3-difluoropropenal.     

Instrumental neutron activation analysis for determination of europium distribution in fattened chicken

From the decay of their most intense -ray, /or rays/, the half-lives of²⁴Na,³¹Si,⁴⁹Ca,⁵²V,¹³⁹Ba,¹⁴²Pr,¹⁵³Sm,¹⁵⁹Gd,¹⁶⁵Dy,¹⁶⁶Ho,¹⁷⁵Yb,¹⁸⁷W,²³³Th and²³⁹U have been redetermined.     

Cellulosic nanoparticles from alfa fibers (<Emphasis Type="Italic">Stipa tenacissima)</Emphasis>: extraction procedures and reinforcement potential in polymer nanocomposites

The microstructure and chemical composition of alfa (Stipa tenacissima) were investigated. The polysaccharide and lignin contents were around 70 and 20 wt%, respectively. From the bleached and delignified fibers, two types of nanosized cellulosic particles were extracted, namely cellulose nanocrystals and microfibrillated cellulose (MFC). The former correspond typically to the elementary crystallite units of the cellulose fibers, with a rod-like morphology and an aspect ratio of about 20. The latter, mechanically disintegrated from oxidized bleached fibres, presents an entangled fibrillar structure with widths in the range 5-20 nm. The reinforcing potential of the ensuing nanoparticles was investigated by casting a mixture of acrylic latex and aqueous dispersion of cellulose nanoparticles. Thermo-mechanical analysis revealed a huge enhancement of the stiffness above the glass transition of the matrix. Significant differences in the mechanical reinforcing capability of the nanoparticles were reported.     

A novel route to prepare highly surface active nanogel particles based on nonaqueous emulsion polymerization

The motivation of the current work has stemmed from the fact that the selection of suitable stabilizers for nonaqueous emulsions is still challenging because of lack of general knowledge about the underlying stabilization mechanisms. The preparation and surface activity of new amphiphilic gel nanoparticles in organic solvents were investigated. A new bifunctional surfmer was prepared by reacting polyoxyethylene 4‐nonyl‐2‐propylene‐phenol nonionic reactive surfactant with maleic anhydride followed by esterification with poly(ethylene glycol). This surfmer was used as stabilizer to prepare amphiphilic crosslinked N‐isopropylacrylamide (NIPAm) and 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) copolymer nanogel on the basis of nonaqueous radical copolymerization temperature modified method in the presence of toluene and formamide (FA) as solvents and N, N‐methylene bisacrylamide as a crosslinker. The chemical structure of the prepared nanogels was determined by Fourier transform infrared spectroscopy analyses. The morphologies of the prepared nanogels were detected by transmission electron microscopy and scanning electron microscopy techniques. The surface tension of colloidal NIPAm/AMPS dispersions was measured in FA as functions of surface age (time), temperature, and the morphology of the NIPAm/AMPS nanogels. The NIPAm/AMPS nanogels reduced the surface tension of FA from 58.2 to about 30.2 mN/m at 25°C, and a little increase in the surface tension was observed at 40°C. The prepared nanogels show great reduction in interfacial tension values between FA and styrene. The NIPAm/AMPS dispersions exhibited high surface activity and used as stabilizers to prepare crosslinked styrene‐co‐AMPS microgel in the presence of divinylbenzene and FA as organic solvents based on nonaqueous emulsion crosslinking polymerization technique. Copyright © 2013 John Wiley & Sons, Ltd.