Volume 70, Issue 3

The synthesis of a new chromogenic N,N′-phenyltetrazole receptor is reported here. The cationbinding properties of this receptor in solution were investigated by naked-eye colour change, electrochemical methods and UV-Vis spectroscopy in various solvents (CH 3 CN, dimethylsulphoxide (DMSO), DMSO/H 2 O, CH 3 CN/H 2 O and CH 3 CN/MeOH). In addition, the receptor was used as a sensing material in ion-selective membrane electrodes. The selectivity and sensitivity of these electrodes towards alkali, alkali-earth, transition and heavy metal cations in aqueous solution were tested. The relation between the carrier structure and membrane plasticisers was investigated.

Pompe disease, glycosomal storage disorder type II, is caused by a deficiency of lysosomal exo-α- 1,4-glucosidase, which participates in glycogen degradation. Due to the wide variety of its clinical symptoms, this lysosomal storage disorder is difficult to diagnose. The “gold standard” diagnosis of Pompe disease is based on an enzyme activity analysis in leucocytes, dried blood spots or tissues, followed by confirmation through mutational analysis. Screening of many inborn metabolic diseases normally requires also the detection of a specific metabolite. In Pompe disease, high levels of a specific glucose tetrasaccharide, αGlc(1→6)αGlc(1→4)αGlc(1→4)Glc, accumulate in patients’ urine. Some medical laboratories continue to favour traditional 1-dimensional TLC for the analysis of urine oligosaccharides, however, this method has some limitations in its analytical specificity and sensitivity. More modern and robust spectral techniques, including mass spectrometry and NMR spectroscopy, possess many advantages and are increasingly used. Here, the different analytical methods applied in Pompe disease diagnosis are experimentally compared.

The aim of this study was to examine the impact of osmotic pressure, regulated by an addition of different NaCl concentrations, on the production parameters and activity of the enzymes involved in the biosynthesis of erythritol from glycerol by Yarrowia lipolytica yeast. In the bioreactor batchcultures, strain A-3 was able to produce from 25.3 g dm -3 to 84.7 g dm -3 of erythritol from 150 g dm -3 of glycerol depending on the initial osmotic pressure. At the osmolality of 4.2 mol kg -3 or higher, a long lag-phase was observed. An enhancement of the production parameters was observed in a culture with the osmotic pressure maintained at an equal level by a step-wise addition of NaCl. The two-hour exposure of strain A-3 cells to 75 g dm -3 of NaCl resulted in decreased activity of glycerol kinase and glycerol-3-phosphate dehydrogenase by about 78 % and 25 %, respectively. The activity of transketolase and erythrose reductase remained unchanged after the salt addition. It was demonstrated that assimilation of glycerol was effective at lower osmotic pressures and that transketolase and erythrose reductase played a significant role in the erythritol formation in Y. lipolytica.

Two genes coding endo-β-1,4-glucanases were cloned from Trichoderma asperellum PQ34 which was isolated from Thua Thien Hue province, Vietnam. The expression of these genes in Pichia pastoris produced two enzymes with molecular masses of approximately 46 kDa (about 42 kDa of enzymes and 4 kDa of signal peptide). The effects of induction time and temperature, inducer concentration, and culture medium on the endo-β-1,4-glucanase activity were investigated. The results showed that the highest total activities of two endo-β-1,4-glucanases were approximately 4.7 × 10 -8 kat (from Glu1-TA gene) and 7.3 × 10 -8 kat (from Glu2-TA gene) occurred after 4 days of induction using 25 mL L -1 methanol at 30°C when the yeast cells were cultured in a YPL medium.

A series of nickel-modified Y zeolites were prepared for the adsorption of dimethyl sulphide (DMS) in liquid hydrocarbon streams. The adsorption desulphurisation performance was investigated under ambient conditions of nickel-based adsorbents developed by the liquid-phase ion exchange (LPIE) method and the incipient wetness impregnation (IWI) method with and without the ultrasonic aid technique. It was found that the nickel-modified Y zeolite prepared by the IWI method with the ultrasonic aid technique with hydrogen reduction demonstrated a high sulphur capacity of 69.9 mg of S per g of sorbent at a break-through sulphur level of 10 μg g -1 . The sorbents thus prepared were characterised by elemental analysis, XRD, TPR, H 2 chemisorption, pyridine-FTIR, XPS, and SEM. The results showed that a high dispersion of metallic nickel atoms loaded on Y zeolite had an important role in determining the DMS removal capacity and the adsorption behaviour exhibited a pronounced dependence on the metal introduction method.

Liquid penetrations into hydrophobic capillaries are controlled by the adsorption and diffusion of the solute in the vicinity of the moving meniscus. The wetting process of microporous hydrophobic polyvinylidenefluoride (PVDF) and polytetrafluoroethylene (PTFE) membrane was investigated in both sodium dodecyl benzene sulphonate (SDBS) and diethanolamine (DEA) aqueous solutions. The experimental results revealed that wetting both the PVDF and PTFE membranes in SDBS solutions at high concentrations proceeded in two stages: rapid wetting and slow wetting, but this transition in the wetting rate was not observed during the membrane wetting at low SDBS concentration and in DEA solutions. The membrane wetting process was accelerated by increasing the solution temperature.

An investigation of the analytical separation of free urea from its additive compounds with H 3 PO 4 , HNO 3 , CaSO 4 and Ca(H 2 PO 4 ) 2 , based on the solubility in butan-1-ol (n-butanol, n-BuOH), is reported. Several methods were tested in order to obtain the best leaching efficiency and solvent utilisation. The urea content was determined using the spectrophotometric method. A simple qualitative determination of urea was also performed using a special type of urea indicator-paper developed during the study. The phase composition of the examined materials was studied using an X-ray powder diffraction method. The urea adducts with phosphoric and nitric acid were found to be soluble in n-BuOH, in a similar way as with free urea. However, the solubility of the urea adducts with CaSO 4 and Ca(H 2 PO 4 ) 2 differs from the solubility of free urea, affording an effective separation of these compounds. The solubility of free urea under defined experimental conditions was estimated to be (1.432 ± 0.043) g of urea in 100 cm 3 of n-BuOH. The trace solubilities of urea bound in the adducts CaSO 4 · 4CO(NH 2 ) 2 and Ca(H 2 PO 4 ) 2 · 4CO(NH 2 ) 2 were (8.28 ± 0.61) mg and (29.83 ± 0.63) mg of urea in 100 cm 3 of n-BuOH, respectively. Partial decomposition of Ca(H 2 PO 4 ) 2 to CaHPO 4 was observed during the leaching process.

Membrane separation techniques are extensively used in dairy industry both for milk and cheese whey processing. However, cheese whey might still be considered as a problematic waste despite its high content of many valuable substances, such as proteins, lactose or minerals, which can be further used, e.g. in human nutrition, pharmacy or biotechnologies. Another problem, which food technologists have to face, is variable quality, composition and properties of food materials bringing high demands on manufacturing industry. In this paper, filtration kinetics and separation efficiency during purification and fractionation of cheese whey (sweet and salty) from Czech dairies by pilot-plant filtration (Bollene, France) was studied using tubular membranes (Membralox, USA). Various mineral membranes’ cut-offs were tested and all experiments ran in the retentate recycling mode. The obtained mass concentration factors were between 1.9 and 16.5. Steady state fluxes were calculated from the experimental data using a mathematical model. Fine ultrafiltration on a 5 kDa membrane gave steady state fluxes of 14-19 L m -2 h -1 . The coarse pre-filtration on 100 nm, 200 nm or 500 nm membranes showed various permeate fluxes between 22 L m -2 h -1 and 153 L m -2 h -1 . Despite the high pore sizes of the used membranes, lactose was partially rejected by all membranes tested.

The total phenolics and flavonoids, rutin, early, advanced and finalMaillard reaction products, and antioxidative capacity determined against 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) radical cation and superoxide anion radicals were used for the characterization of the quality of novel rye-buckwheat ginger cakes enriched with rutin (quercetin rutinoside). The cakes were prepared substituting 30 % of rye flour by light buckwheat flour or flour from roasted buckwheat dehulled grains and employing a dough fermentation-like incubation step. Enrichment of ginger cakes with rutin showed protective effect on lysine blockage, improved antioxidant properties, inhibited the formation of furosine and free fluorescent compounds thus stimulating the Maillard reaction progress towards melanoidin formation. The loss of the nutritional quality of cakes enriched with rutin was related to the formation of fluorescent compounds linked to protein and carboxymethyllysine at an advanced stage of the Maillard reaction. It can be concluded that free fluorescence intermediatory compounds, carboxymethyllysine and browning are the best chemical markers for the characterization of the quality of this novel type of ginger cakes. This study also indicates that rye-buckwheat ginger cakes enriched with rutin can be recommended for wider consumption since daily consumption of 250 g of these cakes may have a prophylactic or therapeutic effect corresponding to typical pharmacological drugs with rutin as the active component.

Lanthanum sulfophenyl phosphate (LaSPP) was synthesized by m-sulfophenyl phosphonic acid and lanthanum nitrate. UV-Vis spectrophotometry and Fourier-transform infrared spectroscopy indicate that the desired product was obtained and its elementary composition and typical layered structure were determined by energy dispersive X-ray spectroscopy and scanning electron microscopy. Transmission electron microscopy (TEM) proved its typical layered structure and X-ray diffraction spectroscopy indicated its good crystallinity and the interlayer distance of about 15.67 Å , which matches the value obtained by TEM (2.0 nm). Thermogravimetry and differential thermal analysis revealed good thermal stability of LaSPP. Proton conductivity of LaSPP was measured at different temperatures and relative humidities (RH), reaching values of 0.123 S cm -1 at 150°C and 100 % RH. Proton transfer activation energy was 22.52 kJ mol -1 . At 160°C and 50 % RH, the conductivity was 0.096 S cm -1 . In the drying oven, the conductivity retained the value of 1.118 × 10 -2 S cm -1 . The results show that LaSPP is a highly effective inorganic-organic conductor.

Porous polypropylene membranes were coated with plasma polymerized titanium isopropoxide in a 75 kHz plasma reactor. It was noted that the presence of air in the plasma chamber increased the amount of deposited polymer. Selection of the process parameters enabled obtaining membranes with up to 300 μg cm -2 of polymerized titanium isopropoxide. Deposition of the titanium oxide layer resulted in the reduction of permeate flux but it significantly improved the membrane photocleaning ability. The recovery index reached the level of 95 % for membranes with the highest amount of the titanium oxide deposit.

The autoignition technique using glycine as fuel and related nitrate salts as an oxidiser is able to produce zinc aluminate spinel. The precursors were synthesised with lean and rich fuel at pH of 7.0 and the materials so obtained were calcined at various temperatures ranging from 600-1200°C. The autoignition process of precursors was studied by the simultaneous thermo-gravimetric and differential thermal analyses to determine the ignition mechanism. The calcined powders were characterised by X-ray diffraction, Brunauer-Emmett-Teller technique and transmission electron microscopy. The product contains nano-sized particles with an average size of approximately 20 nm. The XRD patterns showed the formation of ZnO in the powder obtained by the fuel-rich precursor and calcined at 600°C which disappears at 800°C due to solid-state reaction and proper crystallisation after heat treatment. The results presented here can be useful in manufacturing nano and micro-sized ZnAl 2 O 4 on an industrial scale using the combustion technique.

In this study, the preparation of poloxamer 188-coated poly(butyl cyanoacrylate) colloidal nanospheres of controlled size distribution and their physicochemical characterisation were investigated and their cytotoxic effects in cervical carcinoma (HeLa) cells evaluated. The nanoparticles were prepared by controlled emulsion polymerisation of butyl cyanoacrylate in an aqueous medium containing poloxamer 188 as an amphiphilic non-ionic colloidal stabiliser. The colloids thus obtained were characterised by scanning electron microscopy, dynamic and electrophoretic light-scattering, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. The average size of the particles could be finely controlled within an interval between 220 nm and 290 nm by varying the concentration of the precursor and citric acid in the polymerisation medium. The particle zeta-potentials in phosphate-buffered saline were approximately -4.5 mV. FTIR and NMR data confirmed the expected composition of nanoparticles and the complete precursor polymerisation. In-vitro studies with cervical carcinoma (HeLa) cells demonstrated the dose-dependent cytotoxicity of nanoparticles (IC50 ≈ 30 μg mL -1 ). Observations by phase contrast and fluorescence microscopy revealed that at cytotoxic concentrations (40 μg mL -1 ) nanoparticles induced changes in cell morphology and chromatin fragmentation. The colloidal stabiliser (poloxamer 188) alone was not cytotoxic at the applied concentrations.

A novel chelating surfactant denoted as sodium N-lauroyl ethylenediamine triacetate (N-LED3A) with both surface activity and chelation functions was studied for phenanthrene (PHE) solubilisation ability. The critical micelle concentration (CMC) of N-LED3A was measured, and the effects of the initial N-LED3A concentration, temperature, pH value and coexisting ions (Na + , Ca 2+ and Cu 2+ ) on PHE solubilisation by N-LED3A were investigated. The results demonstrated that PHE solubility was efficiently enhanced by N-LED3A, especially with N-LED3A concentrations above the CMC, which was 707 mg L -1 when measured at 25°C. The temperature influenced the apparent PHE solubility slightly and the apparent solubility of PHE was significantly affected by the pH. Na + and Ca 2+ were shown to increase the PHE solubility, while Ca 2+ exhibited a better promoting ability than Na + . A suitable quantity of Cu 2+ could significantly enhance the solubilisation capacities of N-LED3A at pH 5. The mechanism of the interaction between Cu 2+ and N-LED3A was further confirmed by Fourier transform infrared spectroscopy (FTIR). These results reveal that Cu 2+ can be chelated with N-LED3A to form a chelate complex. The results implied that N-LED3A had the potential to remediate soils contaminated by both organics and heavy metals.

In the present work, the density, ρ, refractive index, n D , and dynamic viscosity, η, for four binary solutions containing ionic liquids [C n mim]X (C n mim = 1-alkyl-3-methylimidazolium; n = 6, 8; X = Cl, Br) and ethylene glycol (EG) were investigated at temperatures of 288.15-333.15 K and at ambient pressure. In addition, the excess molar volume, V E m , was calculated and correlated using the Redlich-Kister polynomial equation. The temperature effect on the density of the binary systems studied was expressed by a linear two-parameter equation. The variation in density, refractive index, and viscosity with the composition was described by polynomial equations. The influence of carbon chain-length and the anion of the ionic liquids, and the influence of the temperature on the physicochemical properties of the binary systems can be explained by comparison of the experimental results.