Electrodeposition of nickel from alkaline NH4OH/NH4Cl buffer solutions

The electrodeposition of nickel on steel and copper from alkaline NH₄OH/NH₄Cl buffer solutions was investigated by cyclic voltammetry (CV), chronopotentiometry (CP), chronoamperometry (CA) as well as an opto-digital microscope, glow-discharge optical emission spectroscopy (GD-OES), XRF, and SEM-EDS techniques. The aim was to obtain Ni coatings from weak alkaline solutions and to optimize the process. The electrolyte composition, pH, temperature as well as current and potential parameters of the process were optimized using the quality of Ni deposit as a criterion. The role of hydrogen evolution in the process was discussed. An influence of Co as an additive was also investigated. It was found that a small amount of Co catalyzes Ni deposition process and improves the quality and color of the deposit. Therefore, in the possible application, the Ni/Co codeposition should be seriously considered. It was also shown that for constant current deposition mode, the width of self-established potential range, revealed at the very beginning of the process by the chronopotentiometric E=f(t) curves, is related to the quality of the coating.     

Textural properties of yogurts with green tea and Pu‐erh tea additive

Set‐style yogurts enriched with green tea or Pu‐erh tea infusions in three concentrations, that is, 5%, 10% and 15% (v/v), and the nonsupplemented yogurts were produced. The obtained cultured milk treatments were subjected to the analyses of acidity, viscoelastic properties, back extrusion parameters, susceptibility to syneresis and instrumental colour analysis. As revealed by the performed HPLC and spectrophotometric studies, the two types of tea differed greatly in their polyphenolic composition which was further reflected in the physicochemical properties of yogurt gels. Results indicate that yogurts varied as regards textural properties depending on the type of tea applied as well as tea concentration. Green tea incorporation, which contained significantly higher amounts of catechins, produced yogurts with increased titratable acidity, better mechanical properties and less susceptible to syneresis, while yogurt gels with Pu‐erh tea were firmer, less elastic and with visible syneresis at higher (10%, 15%) tea concentrations.     

Application of 2D systems to investigation of a process of gas filtration

In the paper, a process of gas filtration described by the 2D system with controls is considered. Sufficient conditions for the existence of optimal process are proved.     

Cholesterol oxides content in selected animal products determined by GC‐MS

The aim of this study was to evaluate the effect of heat treatment of selected animal products on formation of cholesterol oxidation products (COP) and also to determine their content in selected pates and fermented pork sausage which are available on the Polish market. COP content in pates was significantly lower as compared to fermented sausages, and ranged from 39.5 to 43.1 µg/100 g; COP in sausages ranged from 195.8 to 263.4 µg/100 g of product. COP content in pan fried meats, chops, and fish fillets varied from 6.2 to 991.2 µg/100 g products. This paper demonstrates the method for determining the content of COP by the use of selected ion technique with the aid of MS. Practical applications: The method described is useful for the investigation of oxysterols in food matrices. The method is used for the investigation of the presence and content of COP, such as: 7β‐hydroxycholesterol, 5α,6α‐epoxycholesterol, 5β,6β‐epoxycholesterol, 5α‐cholestane‐3β,5β,6β‐triol, 7‐ketocholesterol, and 25‐hydroxycholesterol. The obtained data about COP content in selected animal products and their formation during heat treatment are crucial for creating a reliable database to assess their daily intakes and biological effects in humans.     

Determination of the adulteration of butter

The adulteration of butter is a serious problem due to economic advantages taken by replacing expensive milk fat with cheaper oil without informing the customers. The authentication of milk fat methods include analysis of bulk components, especially triacylglycerols, fatty acids, sterols and tocopherols. Fatty acid and sterol composition was analysed by using GC‐MS. TAG and tocopherol profiles were examined by HPLC with diode array (DAD) and fluorescence detectors (FLDs). In addition, identification of selected TAG of butter fat was conducted by LC‐atmospheric pressure chemical ionisation (APCI)/MS technique. The lipid composition of 16 different butters available on Polish market were investigated. The cholesterol content in butter fat ranged from 176.8 to 264.8 mg/100 g of fat and in two samples of milk fat β‐sitosterol was found. The total saturated fatty acid (SFA) content in milk fat was 67.1–73.5%, monounsaturated fatty acid 24.5–30.5% and polyunsaturated fatty acid was 1.2–2.0%. Abnormalities in fatty acid profiles, e.g. high concentration of linoleic fatty acid, were found in two butters. These abnormalities were also determined in TAG profiles. The examination of tocopherols in butter fat confirmed that two products were adulterated by the addition of plant oils because they contained δ‐tocopherol which is typical for plant origin foodstuffs. The methods described are useful for investigating milk fat adulterations, and the most efficient are analysis of sterols and tocopherols composition. Practical applications: The described methods are useful for investigating adulteration of milk fat. Traditional strategies rely on examination of fatty acids methyl esters and TAG; these methods have some disadvantages. Due to the variability of fatty acid composition of milk fat and because TAG analysis is complex and time consuming, FA analysis is not an efficient approach for butter authentication. The most efficient method for butter authentication is qualitative and quantitative analysis of sterols and tocopherols. This analysis will determine if components of plant origin were used for butter production.     

Characterization of Acidity and Porosity of Zeolite Catalysts by the Equilibrated Thermodesorption of n-Hexane and n-Nonane

Thermodesorption of n-hexane and n-nonane from the acidic and non-acidic zeolites ZSM-5 and Y was studied by means of the thermogravimetric temperature programmed equilibrated desorption (TPED) and quasi-equilibrated temperature programmed desorption and adsorption (QE-TPDA). Micropore volumes determined from the adsorption capacity of n-hexane were close to those determined by N₂ adsorption. Content and strength of acid sites in the acidic zeolites estimated by fitting the Arrhenius equation to the high temperature parts of QE-TPDA profiles of n-hexane attributed to its cracking were in agreement with their acidity characteristics obtained by IR spectroscopy of chemisorbed pyridine. The mesopore volume was determined from the QE-TPDA profiles of n-nonane. Coking observed only for QE-TPDA of n-nonane on H-USY zeolite resulted in blocking the micropores without affecting the mesopores.     

The nanosilica hazard: another variable entity

Silica nanoparticles (SNPs) are produced on an industrial scale and are an addition to a growing number of commercial products. SNPs also have great potential for a variety of diagnostic and therapeutic applications in medicine. Contrary to the well-studied crystalline micron-sized silica, relatively little information exists on the toxicity of its amorphous and nano-size forms. Because nanoparticles possess novel properties, kinetics and unusual bioactivity, their potential biological effects may differ greatly from those of micron-size bulk materials. In this review, we summarize the physico-chemical properties of the different nano-sized silica materials that can affect their interaction with biological systems, with a specific emphasis on inhalation exposure. We discuss recent in vitro and in vivo investigations into the toxicity of nanosilica, both crystalline and amorphous. Most of the in vitro studies of SNPs report results of cellular uptake, size- and dose-dependent cytotoxicity, increased reactive oxygen species levels and pro-inflammatory stimulation. Evidence from a limited number of in vivo studies demonstrates largely reversible lung inflammation, granuloma formation and focal emphysema, with no progressive lung fibrosis. Clearly, more research with standardized materials is needed to enable comparison of experimental data for the different forms of nanosilicas and to establish which physico-chemical properties are responsible for the observed toxicity of SNPs.     

Kinetics of commercial olive oil oxidation: Dynamic differential scanning calorimetry and Rancimat studies

Four samples of olive oil were oxidized under polythermal (dynamic) conditions in the cell of a normal‐pressure differential scanning calorimeter (DSC) and in the Metrohm Rancimat apparatus. The DSC experiments were carried out in an oxygen flow atmosphere using different linearly programmed heating rates in the range of 4–20 °C/min. Through DSC exotherms, the extrapolated onset temperatures were determined and used for the assessment of the thermal‐oxidative stabilities of the samples. Using the Ozawa‐Flynn‐Wall method and the Arrhenius equation, the activation energies (E_a), pre‐exponential factors (Z) and reaction rate constants (k) for oil oxidation under DSC conditions were calculated. The Rancimat measurements of oxidation induction times were carried out under isothermal conditions in an air atmosphere at temperatures from 100 to 140 °C with intervals of 10 °C. Using the Arrhenius‐type correlation between the inverse of the induction times and the absolute temperature of the measurements, E_a, Z, and k for oil oxidation under Rancimat conditions were calculated. The primary kinetic parameters derived from both methods were qualitatively consistent and they help to evaluate the oxidative stabilities of oils at increased temperatures.     

New melamine–formaldehyde–ketone resins. VI. Preparation of filled molding compositions and compression‐molding materials from reactive solvents based on cyclohexanone

The conditions and a method of preparing new molding compositions and filled compression‐molding materials from melamine–formaldehyde–cyclohexanone resins are described. The resins were obtained from melamine solutions in a reactive solvent prepared by the reaction of 1 mol of cyclohexanone with 7 mol of formaldehyde. The fillers were wood powder and sulfite cellulose. The thermal properties of the samples prepared from the compositions were studied with dynamic thermal analysis, thermogravimetry, and differential scanning calorimetry analysis. Selected mechanical properties [Brinell hardness, unnotched impact strength (Charpy method), and bending strength] of the cured resins were also measured. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

γ-Oryzanols of North American Wild Rice (Zizania palustris)

γ-Oryzanol, a natural mixture of ferulic acid esters of triterpene alcohols and sterols, are an important bioactive components present in rice bran oil. In light of the recent increase in the popularity of wild rice among consumers, and the possibility of a direct relationship between γ-oryzanol composition and its bioactivity, the oryzanol profile of major wild rice (Zizania palustris) grown in North America was studied and compared to regular brown rice (Oryza sativa L.). A total of twenty-three γ-oryzanol components were separated, identified and quantified by HPLC coupled to an Orbitrap MS. The distribution of individual γ-oryzanols was similar for all the wild rice but significantly different from those of the regular brown rice. Unlike in the regular brown rice, a significant amount of steryl caffeate and cinnamate were found in the wild rice samples. Generally, the amounts of γ-oryzanol in the wild rice were higher compared to the regular brown rice, 1,352 vs. 688 μg/g. The results from this study showed that wild rice had a more diverse γ-oryzanol composition and the higher amounts compared to the regular brown rice.