Preparation of stable Pd nanoparticles with tunable size for multiple immunolabeling in biomedicine

Stable Pd nanoparticles (PdNP) with a tunable size (3-15 nm) were synthesized by controlled chemical reduction of PdCl₂ with sodium citrate in water. The morphology of PdNP was characterized by transmission electron microscopy, while their stability in solution was verified by quasi-elastic light scattering and small-angle X-ray scattering. Intensive stirring of reacting mixture played a vital role in achieving reproducible particle sizes. Controlled changes of pH and initial concentrations were employed in fine-tuning particle size distributions. Finally, 10 nm PdNP were conjugated with goat anti-mouse IgG antibody as proved by electrophoresis (SDS-PAGE) and used for ultrastructural immunolabeling, which confirmed suitability of PdNP for multiple immunolabeling in biomedicine.     

The perfluoroalkyl substances (PFASs) contamination of fruits and vegetables

Fruit and vegetables play a major role in human nutrition due to richness of nutrients, dietary fibre, and phytochemicals. As dietary intake is identified as one of the dominant exposure pathways to perfluoroalkyl substances (PFASs), a cross-sectional study involving determination of their levels in food of plant origin has been conducted. Locally-grown and imported fruit and vegetable samples, collected in 2016 were inspected for 10 perfluoroalkyl acids (PFAAs) using QuEChERS as sample pre-treatment procedure followed by micro-HPLC-MS/MS. Three of 10 target analytes, perfluorobutanoic acid (PFBA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS) were quantitatively determined. The detection frequency for PFASs across the 55 samples analysed was less than 10%. The major contributor of the total PFASs concentration in the investigated group was PFBA for which the concentration, reported only for banana, apple and orange samples, was 50.740 ng g^?1 ww. The most often detected compound was PFOA. The origin and growing region are possible factors with the potential to influence PFASs distribution profile and their levels in food.     

Polylactide composites with waste cotton fibers: Thermal and mechanical properties

Recently, agricultural by‐products, for instance, corn husks, oat husks, or cocoa shells, have gained attention as a source of cellulose fibers and fillers because they can save the land and other natural resources required to grow fiber crops. It has to be noted, however, that textile processing, for example, shearing, is also a source of waste fibers. Our study focuses on utilization of waste cotton fibers, amassed during shearing of textiles, as a filler for polylactide (PLA). PLA composites with 10–30 wt% of waste cotton fibers were prepared and their thermal and mechanical properties were studied. The composite with 30 wt% of fibers exhibited markedly higher storage and loss moduli as compared with neat PLA; at 25°C the storage moduli increased by 53% whereas the loss modulus increased by 76%. In addition, the yield strength was slightly improved, by 11% at 25°C. Although the composites were thermally less stable than neat PLA, their 5% weight loss temperature remained high, about 300°C. POLYM. COMPOS., 35:747–751, 2014. © 2013 Society of Plastics Engineers     

Optimization of the QuEChERS Method for Determination of Pesticide Residues in Chicken Liver Samples by Gas Chromatography-Mass Spectrometry

The goal of this research was to evaluate the application of Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method for the determination of organochlorine, organophosphate, and carbamate pesticides in fatty animal matrices such as liver of chicken obtained from National Research Institute of Animal Production in Balice (Poland). Pesticides extraction effectiveness was evaluated at two different spiking levels (0.010 and 0.020 mg kg^?1) and efficiency of the dispersive solid-phase extraction (d-SPE) clean-up step was evaluated by comparison adding different d-SPE sorbent combinations (PSA?+?GCB, PSA?+?C₁₈, PSA?+?SAX, and PSA?+?NH₂). The analysis of pesticide residues was performed by gas chromatography ion trap mass spectrometry (GC/IT-MS). The linear relation was observed from 0 to 400 ng mL^?1 and the determination coefficient R ²?>?0.997 in all instances for all target analytes. Better recoveries were obtained in samples at 0.020 mg kg^?1 spiking level. The recoveries were in the range 70–120 %, with relative standard deviation (RSD) values lower than 15 % at 0.020 mg kg^?1 spiking level for most pesticides. Similar recovery ratios were obtained with the four different combinations of sorbents tested in the clean-up step, with better precision when the (PSA?+?SAX) combination was tested. Limits of detection (LODs) ranged from 0.001 to 0.005 mg kg^?1 and limits of quantification (LOQs) ranged from 0.003 to 0.015 mg kg^?1. The proposed method was successfully applied analyzing pesticide residues in real chicken liver samples; detectable pesticide residues were observed, but in all of the cases, the contamination level was lower than the default maximum residue levels (MRLs) set by European Union (EU), Regulation (EC) N 396/2005.     

Consumption of raw brown onions variably modulate plasma lipid profile and lipoprotein oxidation in pigs fed a high‐fat diet

This study was undertaken to determine the effects of two commercially available brown onion varieties, ‘Cavalier’ and ‘Destiny’, supplemented at two different levels, on blood lipid and oxidative status using the pig as a model. Twenty‐five female cross‐bred pigs were allocated to one of five dietary treatments that consisted of a high‐fat control diet with no onion added, a low onion dose of 10 g onion MJ^?1 DE and a high dose of 25 g onion MJ^?1 DE for each variety of onion. Supplementation with ‘Destiny’ onion resulted in a 21% (p < 0.05) reduction in the averaged fasted and postprandial plasma triacylglyceride (TG) measurements taken over the six‐week period in comparison with the control pigs. The average fasting and postprandial plasma cholesterol concentrations were significantly reduced by 5.5 and 12.4% in pigs that consumed the low and high dose of ‘Destiny’ onion, respectively (p < 0.010), while ‘Cavalier’ was only effective at lowering cholesterol levels by 10% at the lower dose of supplementation. Inhibition in the rate of serum lipoprotein oxidation, measured as lag time, was increased by 23% (p < 0.05) in plasma obtained from pigs that consumed ‘Cavalier’ compared with the control and ‘Destiny’ onion diets. These data indicate that onion consumption level may provide a dietary means of manipulating some of the risk indices associated with coronary heart disease, but the responses varied with type and dose of onion. Copyright © 2004 Society of Chemical Industry     

Review of recent applications and research progress in hybrid and combined microwave-assisted drying of food products: Quality properties

Abstract

The growing concerns over product quality have increased demand for high quality dried food products and encouraged researchers to explore and producers of such products to implement novel microwave (MW)-assisted drying methods. This paper presents a critical review of the key principles and drawbacks of MW-assisted drying as well as needs for future research. In this article, recent research into application of microwaves as an alternative heat source, applications and progress in hybrid MW-assisted drying that rely on various drying media and combined two or three stages of MW-assisted drying for the preservation of food products is reviewed critically. The effect of different MW-assisted drying methods, conditions and initial pretreatments on the thermophysical properties, color, nutritional value and rehydration potential of dried food products is discussed in detail along with the discussion on how the material properties evolve and change in structure, color, and composition during MW-assisted drying and recent attempts at mathematical modeling of these changes made for different fruits and vegetables. It should be noted that most of the published results were obtained in laboratory-scale dryers. Pilot-scale testing is needed to bridge the gap between laboratory research and industrial applications to fulfill the potential for novel hybrid and combined MW-assisted drying methods and to expand their role in food processing.     

Structural and pharmacological characterization of phenylalanine-based AMPA receptor antagonists at kainate receptors

Continued efforts into the discovery of ligands that target ionotropic glutamate receptors (iGluRs) are important for studies of the physiological roles of the various iGluR subtypes as well as for the search for drugs that can be used in the treatment of diseases of the central nervous system. A new series of phenylalanine derivatives that target iGluRs was reported to bind AMPA receptors. Herein we report our studies of these compounds at the kainate receptors GluK1-3. Several compounds bind with micromolar affinity at GluK1 and GluK3, but do not bind GluK2. The crystal structure of the most potent compound in the ligand binding domain of GluK1 revealed different modes of binding to GluK1 and GluA2, due primarily to residues Ser741 (GluK1) and Met729 (GluA2). The compound was shown to be slightly more potent at GluK1 than at AMPA receptors and to induce a domain closure similar to that observed in GluK1 structures with partial agonists.     

Impact of Selected Chemical Characteristics of Cold-Pressed Oils on their Oxidative Stability Determined Using the Rancimat and Pressure Differential Scanning Calorimetry Method

In this study, 27 market and edible cold-pressed oils from 10 different oilseeds were analysed. Oxidative stability and the chemical composition of oils were evaluated. The oils were investigated for their primary quality, fatty acid composition, total phenolic content and antioxidant activity. Rancimat and pressure differential scanning calorimetry (PDSC) were used to assess oils oxidative stability. Principal component analysis (PCA) was conducted to determinate impact of selected chemical characteristics on tested oils’ oxidative stability in accelerated modes. PCA indicated that none of the chemical compounds correlated strongly with the oils’ oxidative stability determined by the Rancimat method. Correlation coefficients describing the impact of different chemical compounds on induction time determined using the Rancimat method were between r = ?0.54 (C18:3) to r = 0.62 (chlorophyll pigments). Oxidative stability of oils determined using the Rancimat and pressure differential scanning calorimetry (PDSC) were characterised by low correlation (r = 0.66). According to the statistical analyses, oils were divided into four groups, which depend on the method of oxidative stability evaluation did not differ.