Indene epoxidation over immobilized methyltrioxorhenium on MCM-41 silica,fumed silica and aluminosilicate materials

The presented report focuses on the testing of heterogenized methyltrioxorhenium (MTO) in indene epoxidation. A range of mesoporous materials with different SiO₂/Al₂O₃ ratios, namely aluminosilicates type Siral and MCM-41 silica and fumed silica, were used as supports for immobilization of MTO. The tested support materials and prepared catalytic systems exhibited high surface area, well-defined regular structure and narrow pore size distribution of mesopores and therefore represent good quality catalysts for various reactions. The immobilized MTO on various supports was tested for the preparation of 1,2-epoxyindane using two forms of hydrogen peroxide as oxidation agents, namely aqueous solution of hydrogen peroxide and its anhydrous form, urea-hydrogen peroxide. The prepared catalysts were successfully used for the preparation of 1,2-epoxyindane with achieved 100 % selectivities to the desired product at high conversions of indene.     

High‐Pressure Thermal Sterilization: Food Safety and Food Quality of Baby Food Puree

The benefits that high‐pressure thermal sterilization offers as an emerging technology could be used to produce a better overall food quality. Due to shorter dwell times and lower thermal load applied to the product in comparison to the thermal retorting, lower numbers and quantities of unwanted food processing contaminants (FPCs), for example, furan, acrylamide, HMF, and MCPD‐esters could be formed. Two spore strains were used to test the technique; Geobacillus stearothermophilus and Bacillus amyloliquefaciens, over the temperature range 90 to 121 °C at 600 MPa. The treatments were carried out in baby food puree and ACES‐buffer. The treatments at 90 and 105 °C showed that G. stearothermophilus is more pressure‐sensitive than B. amyloliquefaciens. The formation of FPCs was monitored during the sterilization process and compared to the amounts found in retorted samples of the same food. The amounts of furan could be reduced between 81% to 96% in comparison to retorting for the tested temperature pressure combination even at sterilization conditions of F₀‐value in 7 min.     

Influence of Chemical Precleaning on the Plasma Treatment Efficiency of Aluminum by RF Plasma Pencil

This paper is aimed to show the influence of initial chemical pretreatment prior to subsequent plasma activation of aluminum surfaces.The results of our study showed that the state of the topmost surface layer（i.e.the surface morphology and chemical groups）of plasma modified aluminum significantly depends on the chemical precleaning.Commonly used chemicals（isopropanol,trichlorethane,solution of Na OH in deionized water）were used as precleaning agents.The plasma treatments were done using a radio frequency driven atmospheric pressure plasma pencil developed at Masaryk University,which operates in Ar,Ar/O₂ gas mixtures.The effectiveness of the plasma treatment was estimated by the wettability measurements,showing high wettability improvement already after 0.3 s treatment.The effects of surface cleaning（hydrocarbon removal）,surface oxidation and activation（generation of OH groups）were estimated using infrared spectroscopy.The changes in the surface morphology were measured using scanning electron microscopy.Optical emission spectroscopy measurements in the near-to-surface region with temperature calculations showed that plasma itself depends on the sample precleaning procedure.     

Fate of trichothecene mycotoxins during the processing: Milling and baking

Toxic secondary metabolites produced by fungi representing Fusarium genus are common contaminants in cereals worldwide. To estimate the dietary intake of these trichothecene mycotoxins, information on their fate during cereal processing is needed. Up-to-date techniques such as high-performance liquid chromatography (HPLC) coupled with tandem mass spectrometry (LC-MS/MS) was used for the analysis of seven trichothecenes (deoxynivalenol, nivalenol, HT-2 toxin, T-2 toxin, 15- and 3-acetyldeoxynivalenol, and fusarenon-X) in bread production chain (wheat grains, intermediate products collected during milling and baking process, breads). Regardless of whether the grains were naturally infected or artificially inoculated by Fusarium spp. in the field, the fractions obtained from the grain-cleaning procedure contained the highest mycotoxin levels. During milling the highest concentrations of deoxynivalenol were found in the bran, the lowest in the reduction flours. Baking at 210°C for 14 min had no significant effect on deoxynivalenol levels. The rheological properties of dough measured by fermentograph, maturograph, oven rise recorder, and laboratory baking test were carried out, and based on the obtained results the influence of mycotoxin content on rheological behaviour was investigated.     

Fate of trichothecene mycotoxins during the processing: milling and baking

Toxic secondary metabolites produced by fungi representing Fusarium genus are common contaminants in cereals worldwide. To estimate the dietary intake of these trichothecene mycotoxins, information on their fate during cereal processing is needed. Up-to-date techniques such as high-performance liquid chromatography (HPLC) coupled with tandem mass spectrometry (LC-MS/MS) was used for the analysis of seven trichothecenes (deoxynivalenol, nivalenol, HT-2 toxin, T-2 toxin, 15- and 3-acetyldeoxynivalenol, and fusarenon-X) in bread production chain (wheat grains, intermediate products collected during milling and baking process, breads). Regardless of whether the grains were naturally infected or artificially inoculated by Fusarium spp. in the field, the fractions obtained from the grain-cleaning procedure contained the highest mycotoxin levels. During milling the highest concentrations of deoxynivalenol were found in the bran, the lowest in the reduction flours. Baking at 210 degrees C for 14 min had no significant effect on deoxynivalenol levels. The rheological properties of dough measured by fermentograph, maturograph, oven rise recorder, and laboratory baking test were carried out, and based on the obtained results the influence of mycotoxin content on rheological behaviour was investigated.     

Fluorine containing self‐crosslinking acrylic latexes with reduced flammability and their application as polymer binders for heterogeneous cation‐exchange membranes

In this study, self‐crosslinking core–shell latexes comprising copolymerized perfluorethyl groups and a novel flame retardant based on phosphazene derivative were prepared by the semi‐continuous non‐seeded emulsion polymerization of 2,2,2‐trifluorethyl methacrylate, methyl methacrylate, butyl acrylate, methacrylic acid, and hexaallylamino‐cyclo‐triphosphazene as main monomers. For interfacial crosslinking, diacetone acrylamide was copolymerized into the shell layer of latex particles to provide sites for subsequent reaction with adipic acid dihydrazide. The heterogeneous cation‐exchange membranes were obtained by dispersing commercial strong acid cation‐exchange resin powder in the latex binder and casting the mixture followed by keto‐hydrazide crosslinking reaction. It was found that the increased concentration of fluorine atoms and phosphazene units in the macromolecular structure of interfacially crosslinked emulsion polymers resulted in a significant enhancement of their flame resistance and shape stability in aqueous environment. Moreover, the easily prepared heterogeneous cation‐exchange membranes based on latexes with higher amounts of fluorine and phosphazene units were shown to exhibit satisfactory physicochemical and electrochemical properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45467.     

AFM imaging and analysis of local mechanical properties for detection of surface pattern of functional groups

In this work we evaluate the applicability of different atomic force microscopy (AFM) modes, such as Phase Shift Imaging, Atomic Force Acoustic Microscopy (AFAM) and Force Spectroscopy, for mapping of the distribution pattern of low-molecular-weight biomimetic groups on polymer biomaterial surfaces. Patterns with either random or clustered spatial distribution of bioactive peptide group derived from fibronectin were prepared by surface deposition of functional block copolymer nano-colloids and grafted with RGDS peptide containing the sequence of amino acids arginine–glycine–aspartic acid–serine (conventionally labeled as RGDS) and carrying biotin as a tag. The biotin-tagged peptides were labeled with 40 nm streptavidin-modified Au nanospheres. The peptide molecules were localized through the detection of bound Au nanospheres by AFM, and thus, the surface distribution of peptides was revealed. AFM techniques capable of monitoring local mechanical properties of the surface were proved to be the most efficient for identification of Au nano-markers. The efficiency was successfully demonstrated on two different patterns, i.e. random and clustered distribution of RGDS peptides on structured surface of the polymer biomaterial.     

Fate of trichothecene mycotoxins during the processing: milling and baking.

Toxic secondary metabolites produced by fungi representing Fusarium genus are common contaminants in cereals worldwide. To estimate the dietary intake of these trichothecene mycotoxins, information on their fate during cereal processing is needed. Up-to-date techniques such as high-performance liquid chromatography (HPLC) coupled with tandem mass spectrometry (LC-MS/MS) was used for the analysis of seven trichothecenes (deoxynivalenol, nivalenol, HT-2 toxin, T-2 toxin, 15- and 3-acetyldeoxynivalenol, and fusarenon-X) in bread production chain (wheat grains, intermediate products collected during milling and baking process, breads). Regardless of whether the grains were naturally infected or artificially inoculated by Fusarium spp. in the field, the fractions obtained from the grain-cleaning procedure contained the highest mycotoxin levels. During milling the highest concentrations of deoxynivalenol were found in the bran, the lowest in the reduction flours. Baking at 210 degrees C for 14 min had no significant effect on deoxynivalenol levels. The rheological properties of dough measured by fermentograph, maturograph, oven rise recorder, and laboratory baking test were carried out, and based on the obtained results the influence of mycotoxin content on rheological behaviour was investigated.     

αV Integrin Expression and Localization in Male Germ Cells

Integrins are transmembrane receptors that facilitate cell adhesion and cell–extracellular matrix communication. They are involved in the sperm maturation including capacitation and gamete interaction, resulting in successful fertilization. αV integrin belongs to the integrin glycoprotein superfamily, and it is indispensable for physiological spermiogenesis and testosterone production. We targeted the gene and protein expression of the αV integrin subunit and described its membrane localization in sperm. Firstly, in mouse, we traced αV integrin gene expression during spermatogenesis in testicular fraction separated by elutriation, and we detected gene activity in spermatogonia, spermatocytes, and round spermatids. Secondly, we specified αV integrin membrane localization in acrosome-intact and acrosome-reacted sperm and compared its pattern between mouse, pig, and human. Using immunodetection and structured illumination microscopy (SIM), the αV integrin localization was confined to the plasma membrane covering the acrosomal cap area and also to the inner acrosomal membrane of acrosome-intact sperm of all selected species. During the acrosome reaction, which was induced on capacitated sperm, the αV integrin relocated and was detected over the whole sperm head. Knowledge of the integrin pattern in mature sperm prepares the ground for further investigation into the pathologies and related fertility issues in human medicine and veterinary science.     

Characterization of Molecular Structure of Emulsion Acrylic Microgels: Exploring the Impact of Molar Mass on Coating Properties of Self-Cross-Linkable Latexes

Self-cross-linkable latexes of core–shell microgel particles were synthesized by the emulsion polymerization of acrylic monomers. The molar mass of copolymers forming the shell layer was gradually reduced by isooctyl 3-mercaptopropionate included in the synthesis of the shell layers. The molar mass distribution of latex particles was determined using size exclusion chromatography and asymmetric flow field-flow fractionation, respectively, both separation methods being coupled with a multiangle light scattering detector. The results confirmed theoretical predictions and described empirically the effects of molar mass of the shell layer copolymer on decreasing the minimum film-forming temperature and influencing the end-use properties of coatings.