Protein A carrying monosize PMMA microbeads for the removal of HIgG from human plasma

Protein A-incorporated polymethylmethacrylate (PMMA) microbeads were investigated for specific removal of HIgG from human plasma. The microbeads were prepared by a phase inversion polymerization, and activated by periodate oxidation. Protein A was then incorporated by covalent binding onto these microbeads through hydroxyl groups coming from the stabilizer. The amount of incorporated protein A was controlled by the initial concentrations of protein A in the immobilization medium and pH. The maximum protein A immobilization of 0.615 mg protein A/g PMMA, was observed at a pH of 9.5 corresponding to an initial protein A concentration of 0.1 mg/ml. There was no HIgG adsorption onto the plain PMMA microbeads, while high HIgG adsorptions of up to 32 mg HIgG/g PMMA were achieved with human plasma.     

Drying behaviour of hazelnuts

A diffusion-based drying model has been used to model the single-layer drying of whole hazelnuts (hull, air-gap and kernel). The drying of whole hazelnut was simulated by means of the numerical solution of Fick's second law for a composite solid consisting of an air gap which is between two solid bodies. The Crank–Nicholson implicit numerical method has been applied to solve the diffusion equation with variable mass diffusivity for whole hazelnut. The numerical data so obtained has been presented in the form of a series of curves which represent the drying characteristics of a whole hazelnut. Experimental results from whole hazelnuts were correlated with the theoretical results. A correlation describing the diffusivity of the whole hazelnut with moisture content and temperature was established, when the expression of diffusivity for hazelnut was used. Predicting the drying behaviour of the hazelnut for a known value of initial moisture content, equilibrium moisture and equivalent radius, a good agreement was obtaind between the experimental data and prediction. Whole hazelnut diffusivity was determined at 25–45°C, air velocity 0·2–0·3 ms⁻¹, 60% relative humidity of air, using the theoretical curves that best fit the data. The diffusivity of whole hazelnut was determined as a function of drying air temperature and velocity. © 1998 SCI.     

Production of bacterial cellulose fibers in the presence of effective microorganism

In this study, effective microorganism (EM) was added into fermentation medium in static culture to enhance bacterial cellulose (BC) production by Acetobacter xylinum 23769 strain. According to SEM micrographs, BC pellicles from BC-Baikal EM1 show a smaller diameter and a relatively narrow diameter distribution compared to BC pellicles from Hestrin–Schramm (HS) medium. The BC-HS absorbed 90.5 times its dry weight of water. The water holding capacity increased to 132.5 for BC-Baikal EM1 medium compared to BC-HS. From the FT-IR spectra, BC samples exhibited a similar pattern. The crystalline indices of Baikal EM1-altered BC (66%) were lower than Baikal EM1-free BC (71%).     

A new flavone from antioxidant extracts of Pistacia terebinthus

Acetone and methanol extracts of the fruits of Pistacia terebinthus L. subsp. terebinthus L. were studied for their antioxidant activity by investigating their total phenolic and flavonoid contents, β-carotene bleaching potential, DPPH radical scavenging effect, scavenging activity on superoxide anion radical, reducing power, and metal chelating effect on ferrous ion. Both extracts showed very similar chemical profile by checking on TLC plates, and exhibited high scavenging activity on superoxide anion radical and DPPH radical. Due to these similarities they were combined and fractionated on a silica gel column for their constituents, and the most active three fractions in DPPH assay were purified to afford a new flavone 6′-hydroxyhypolaetin 3′-methyl ether (1) besides a group of known flavonoids apigenin, luteolin, luteolin 7-O-glucoside, quercetin, quercetagetin 3-methyl ether 7-O-glucoside, isoscutellarein 8-O-glucoside. Their structures were established by UV, UV shift reagents, and ¹H NMR spectroscopic techniques. Antioxidant activity of the new flavone was investigated by β-carotene bleaching and DPPH radical scavenging activity methods, and it showed a high activity in the first system, but not so good in the latter.     

Determination of Phthalate Residues in Different Types of Yogurt by Gas Chromatography-Mass Spectrometry and Estimation of Yogurt-Related Intake of Phthalates

Phthalates are potential endocrine-disrupting chemicals, found widely in the environment, and commonly used to make plastics softer and more flexible. Little information is available about the presence of phthalates in yogurt products sold on the world market. This study aimed to develop a sensitive GC-MS method for the determination of selected phthalates in yogurt and residue levels in fruit yogurts together with the packaging materials and to estimate a yogurt-related exposure to phthalates in the Turkish population. Acetonitrile extraction followed by cleanup procedures using different adsorbents yielded relatively clean extracts. The presence as the percent of selected phthalates tested—dibutyl phthalate (DBP), diethylhexyl phthalate (DEHP), dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-octyl phthalate (DNOP), and benzyl butyl phthalate (BBP)—were determined as 76, 70, 70, 54, 20, and 8% of the samples, respectively, for the phthalates, ranging from <LOQ to 1640 μg/kg. The highest concentrations were found in cherry yogurt among the fruit yogurts, while banana and pineapple yogurts contained the least. The results indicate that the estimated daily intakes for phthalates were below tolerable daily intakes.     

Determination of Selected Polychlorinated Biphenyl Residues in Meat Products by QuEChERS Method Coupled with Gas Chromatography–Mass Spectrometry

Polychlorinated biphenyl (PCB) residues in food are an important food safety concern. Simple and sensitive analytical methods are needed to monitor PCB residues and ensure that food is safe for consumption. The aim of this study was to adapt a selective, sensitive, quick, and easy sample treatment for purification of animal fat matrices and to measure the level of PCB28, PCB52, PCB101, PCB118, PCB138, PCB153, and PCB180 in samples of meat products (salami, soudjouk, and sausage) produced in Turkey. The extraction and purification of meat products were performed via the modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method and PCB levels determined by gas chromatography–mass spectrometry. The linearity was satisfactory for all compounds studied, with correlation coefficients ≥0.99. The limits of determination and the limits of quantification were in the range of 0.144–0.382 and 0.479–1.274 ng g^?1, respectively. Recovery at 3 different spiking concentrations was 95.7–101 % and the relative standard deviations were <3.5 %. This validated method was observed to be more economic and eco-friendly, as it uses a smaller volume of extraction solvents that are also less toxic. The validated method was successfully applied to the analysis of selected PCBs in meat products with satisfactory results. The method’s results indicated the presence of PCBs in some of the meat product samples, although the levels were below the maximum residue limit for food products of animal origin in Turkey (40 ng g^?1 of fat), which is in accordance with EU and Turkish levels.     

Dominant Factor in the Collapse of WTC-1

The behavior of the World Trade Center Tower 1 on September 11, 2001 is studied in light of experimental data on the effect of elevated temperature on mechanical properties of structural steel. It is concluded that the damage inflicted by aircraft impact on the insulation of the core framing was the dominant factor in the collapse of the structure.