Zur Oxydationsreaktion von Magnetit

Verlauf des Oxydationsvorganges von Magnetiten verschiedener Herkunft. Ergebnisse der gravimetrischen und der Differentialthermoanalyse sowie der Röntgenstrukturuntersuchung. Sättigungsmagnetisierung des oxydierten Magnetits. Mößbauerspektren des Magnetits bei verschiedenen Oxydationsgraden. Einflüsse auf den Mechanismus und die Kinetik des Oxydationsvorganges des Magnetits.     

Occurrence of ochratoxin A-producing fungi in grapes grown in Italy

A study was carried out to investigate fungi present on grapes grown in Italy. Aspergillus and Penicillium spp. isolates were identified and studied in vitro, and their ability to produce ochratoxin A (OA) was investigated. The survey involved nine vineyards, three located in northern Italy and six located in southern Italy. In 1999 and 2000, bunches of grapes at different growth stages were collected from all nine vineyards, and berry samples were placed in moist chambers and incubated. The resultant fungal colonies were then transferred to petri dishes containing Czapek yeast agar and incubated at 25 degrees C for 7 days; the fungal isolates were identified and then cultivated in liquid Czapek yeast medium and evaluated for their ability to produce OA. During the survey, 508 isolates were collected, with 477 belonging to Aspergillus spp. and 31 belonging to Penicillium spp. Among the aspergilli, species of the Fumigati, Circumdati, and Nigri sections were identified, with species of the Nigri section (464 isolates) largely predominating; for species of the Nigri section, 108 isolates were uniseriate, 270 were biseriate, and 86 were identified as Aspergillus carbonarius. Black aspergilli isolated over the 2 years of the study showed a very similar pattern. On average, the biseriates represented about 60% of the isolates collected in both years and were followed by uniseriates (21%) and A. carbonarius (19%). The most toxigenic strains proved to be those of A. carbonarius; about 60% of these isolates were OA producers and produced the highest levels of OA. A. carbonarius was more frequent in the south, but in both areas the percentages of OA-producing isolates remained the same.     

Work Satisfaction,Causes, and Sources of Job Stress and Specific Ways of Coping: A Case Study of White‐Collar Outsourcing Service Employees

This study investigated work‐related stresses in the business outsourcing service environment. Eighty‐six white‐collar professionals who occupied low‐level managerial positions in a business accounting outsourcing company took part in the field study. The derived scales for the sources of stress, work satisfaction, and coping with stress had different structure than those contained in the original occupational stress indicator scale of Cooper, Sloan, and Williams (1988). The study results also illustrate that the observed sources of work stress perceived by white‐collar employees of the outsourcing firm are unique to this occupational group and specific to this sector of business activity. Future research efforts will focus on comparative analysis of work stress in outsourcing companies across different cultures. © 2013 Wiley Periodicals, Inc.     

Properties of \text{max-}* fuzzy relation equations

We extend the result of Zhang et al. (J Fuzzy Math 14:53, 2006), who discussed the finite fuzzy relation equations with max–min and max–prod composition. In this article, the $\text{max-}*$ composition is used for wide family of operations $*$ . In particular, families of solutions of two relation equations are compared.     

The density of truth in monadic fragments of some intermediate logics

This paper is an attempt to count the proportion of tautologies of some intermediate logics among all formulas. Our interest concentrates especially on Medvedev’s logic and its fragment over language with one propositional variable.     

Effect of microgels on the viscoelastic properties of poly(dimethylvinylsiloxanes)

The course of dynamic viscosity η′ and modulus of elasticity G′ curves versus frequency of oscillations f was compared for poly(dimethylvinylsiloxanes) (PDMVS) samples of similar weight-average molecular weights containing 0.1–0.2% by weight of microgels and free of microgels. It was found that the presence of microgels considerably changes the viscoelastic properties of PDMVS, particularly in the low-frequency range. Only for samples with microgels a linear course of the above-mentioned curves is observed. The content of microgels was determined by the light scattering method, whereas the η′ and G′ versus f values were obtained with the use of the Weissenberg rheogoniometer.     

Pathophysiology of the Different Clinical Phenotypes of Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP)

Chronic inflammatory demyelinating polyneuropathy (CIDP) is the most common form of autoimmune polyneuropathy. It is a chronic disease and may be monophasic, progressive or recurrent with exacerbations and incomplete remissions, causing accumulating disability. In recent years, there has been rapid progress in understanding the background of CIDP, which allowed us to distinguish specific phenotypes of this disease. This in turn allowed us to better understand the mechanism of response or non-response to various forms of therapy. On the basis of a review of the relevant literature, the authors present the current state of knowledge concerning the pathophysiology of the different clinical phenotypes of CIDP as well as ongoing research in this field, with reference to key points of immune-mediated processes involved in the background of CIDP.     

Adsorption properties of carbonized polyacrylonitrile deposited on γ-alumina and silica gel by precipitation polymerization

The precipitation polymerization method was used for the deposition of various contents of polyacrylonitrile on two oxide-type supports (γ-alumina and silica gel). The synthesized materials were characterized by thermal analysis performed in inert and oxidizing atmospheres. The mechanism of polyacrylonitrile decomposition was proposed. In order to gain effective adsorbents of volatile organic compounds the polyacrylonitrile/support composites were carbonized at elevated temperatures. The texture and morphology of the calcined materials were examined by low-temperature sorption of N₂ and scanning electron microscopy, respectively. An influence of thermal treatment conditions and carbonaceous species loading on adsorption capacity of methyl-ethyl ketone vapour was also determined. Attenuated total reflection Fourier transform infrared spectroscopy measurements revealed that the ladder-type polyacrylonitrile species formed above 250 °C and stable up to about 350–400 °C are the most effective sites for methyl-ethyl ketone sorption. The carbonaceous species dispersion was found to be an additional factor influencing the adsorption capacity of the carbonized polyacrylonitrile/support composites.     

Optimization of Multilayer Films Composed of Chitosan and Low-Methoxy Amidated Pectin as Multifunctional Biomaterials for Drug Delivery

Polyelectrolyte multilayers (PEMs) based on polyelectrolyte complex (PEC) structures are recognized as interesting materials for manufacturing functionalized coatings or drug delivery platforms. Difficulties in homogeneous PEC system development generated the idea of chitosan (CS)/low-methoxy amidated pectin (LM PC) multilayer film optimization with regard to the selected variables: the polymer ratio, PC type, and order of polymer mixing. Films were formulated by solvent casting method and then tested to characterize CS/LM PC PECs, using thermal analysis, Fourier transform infrared spectroscopy (FTIR), turbidity, and zeta potential measurements. The internal structure of the films was visualized by using scanning electron microscopy. Analysis of the mechanical and swelling properties enabled us to select the most promising formulations with high uniformity and mechanical strength. Films with confirmed multilayer architecture were indicated as a promising material for the multifunctional systems development for buccal drug delivery. They were also characterized by improved thermal stability as compared to the single polymers and their physical mixtures, most probably as a result of the CS–LM PC interactions. This also might indicate the potential protective effect on the active substances being incorporated in the PEC-based films.     

Retention of mineral constituents in frozen brassicas depending on the method of preliminary processing of the raw material and preparation of frozen products for consumption

The content of ash, P, K, Ca, Mg, Na, Fe, Zn, Mn, Cu, Cr and Ni was determined in four species of brassicas: Brussels sprouts, broccoli, and green and white cauliflowers. The investigation covered the raw material, the material blanched or cooked before freezing and frozen products after 12 months of refrigerated storage and prepared for consumption. Frozen products were obtained by the traditional method of freezing the blanched material or by the modified method of freezing the cooked material. The processing of vegetables before freezing (washing, grinding, blanching or cooking) caused statistically significant decreases in most constituents analysed. Blanching did not basically change the content of sodium and calcium; or that of chromium in both types of cauliflower; copper and nickel in white cauliflower; and nickel and phosphorus in Brussels sprouts. Cooking in brine, however, caused increases in the content of ash, sodium and calcium in white cauliflower, decreases in the content of potassium and iron and, in some species, of the remaining constituents. In comparison with the traditional method, a greater content of most analysed elements was found in frozen products obtained by the modified technology and prepared for consumption. However, no significant differences were noted in the level of chromium in all the samples; in the level of calcium in broccoli and green cauliflower; of nickel in broccoli; of nickel, copper and zinc in white cauliflower; and of copper in green cauliflower.