Interstitial effects of B addition on the metamagnetic transition and magnetocaloric effect in tetragonal Cu2Sb-type Mn1.95Cu0.05Sb alloys

Mn_1.95Cu_0.05SbB_x (x = 0, 0.06 and 0.1) alloys had been prepared and B interstitial effects on metamagnetic transition were studied. The metamagnetic transition temperature was reduced and thermal hysteresis was widened by higher B concentration. The saturation magnetization and the magnetic entropy change were increased by moderate amount of B addition. However, too high B composition led into the sluggish metamagnetic transition. By relating with crystallographic structure, our results further indicated that the electron density of the atoms at MnⅡ position plays critical role on influencing the metamagnetic transition in tetragonal Cu₂Sb-type Mn_1.95Cu_0.05Sb alloys.     

Metals in organic and conventional wheat flours determined by an optimised and validated ICP‐MS method

This study was undertaken (i) to optimise and validate a suitable method for multi‐element determination in cereal products and (ii) to evaluate multi‐element content differences in commercially available conventional vs. organic wheat flours. Presented ICP‐MS method is simple and accurate for the determination of eighteen elements in cereal food. Obtained results show differences in metal content between conventional and organic wheat flours and confirm that both types of production are well within the toxicological safety limits regarding the metal contents. The significant differences among conventional vs. organic wheat flours were obtained for As, Cd, Cr, Fe, Mg, Mo, Ni and V. Toxic metals (Al, As, Cd and Pb) input was higher in conventional compared with organic wheat flours. However, further and long‐term research is needed to clearly underline the effects of organic agricultural practice on the quality of food products.     

An investigation of the electrical transport properties of graphene-oxide thin films

The electrical transport properties of graphene-oxide (GO) thin films were investigated. The GO was synthesized by a modified Hummers method and was characterized by X-ray diffraction and UV-visible spectroscopy. The thin film of GO was made on a Si/SiO₂ substrate by drop-casting. The surface morphology of the GO film was analyzed by using scanning electron microscopy and atomic force microscopy techniques. Temperature dependent resistance and current-voltage measurements were studied using four-terminal method at various temperatures (120, 150, 175, 200, 250 and 300 K) and their charge transport followed the 3D variable range hopping mechanism which was well supported by Raman spectra analysis. The presence of various functional groups in GO were identified by using high resolution X-ray photo electron (XPS) and Fourier transform infra red (FT-IR) spectroscopic techniques. Graphene-oxide thin film field effect transistor devices show p-type semiconducting behavior with a hole mobility of 0.25 cm² V⁻¹ s⁻¹ and 0.59 cm² V⁻¹ s⁻¹ when measured in air and vacuum respectively.     

Organic whey as a source of Lactobacillus strains with selected technological and antimicrobial properties

Twenty‐five strains, isolated from raw, non‐pasteurised, organic whey samples, were identified phenotypically and genotypically. Biochemical tests were performed, and enzyme profiles, antibiotic resistance and antimicrobial properties were investigated. Sixteen strains were identified as genus Lactobacillus. Based on 16S rDNA gene sequence, the strains were identified as Lb. plantarum and Lb. fermentum. All of the strains had β‐galactosidase activity, and some of them reduced nitrate content. All strains utilised carbohydrates. The tested strains were characterised by low or average lipolytic and esterolytic activity. Moreover, the strains showed low proteolytic activity which is advantageous for their use as starter cultures for foods with low protein content. Strains Lb. fermentum S20, SM1, SM3, S2R and Lb. plantarum SM5 produced harmful N‐acetyl‐β‐glucosaminidase; moreover, the strain S20 produced also β‐glucuronidase. None of the strains produced α‐chymotrypsin. In phenotypic studies, most of the test strains were susceptible to gentamicin, ampicillin, tetracycline, chloramphenicol, penicillin and erythromycin. Strains Lb. plantarum S1 and Lb. fermentum S4, S7, S8, S10, SM1 and SM3 did not possess any transfer resistance genes. Antagonistic activity of the culture LAB strains was assessed as high or moderate in relation to the indicator strains, with the greatest zones of inhibition for E.coli and the smallest for L. monocytogenes ATCC 15313. This study reveals that the LAB strains isolated from organic whey have high potential for food application. Some strains of species Lb. fermentum (S4, S7, S8, S10) have been identified as the best candidates.     

Synthesis and properties of sulfonated poly(arylene ether ketone sulfone) containing amino groups/functional titania inorganic particles hybrid membranes for fuel cells

In this work, the organic-inorganic hybrid membranes were prepared. The synthesis and properties of the hybrid membranes were investigated. The sulfonated poly(arylene ether ketone sulfone) containing amino groups (Am-SPAEKS) was synthesized by nucleophilic polycondensation. The sol-gel method was used to prepared functional titania inorganic particles (L-TiO₂). The ¹H NMR and FT-IR were performed to verified the structure of Am-SPAEKS and L-TiO₂. The organic-inorganic hybrid membranes showed both good thermal stabilities and mechanical properties than that of Am-SPAEKS. The L-Am-15% membrane exhibited the highest Young's modulus (2262.71 MPa) and Yield stress (62.09 MPa). The distribution of L-TiO₂ particles was revealed by SEM. Compared to Am-SPAEKS, the hybrid membranes showed higher proton conductivities. The L-Am-15% exhibited the highest proton conductivity of 0.0879 S cm⁻¹ at 90 °C. The results indicate that the organic-inorganic hybrid membranes have potential for application in proton exchange membrane fuel cells.     

Opportunities for plant-derived enhancers for iron,zinc, and calcium bioavailability: A review

Understanding of the mechanism of interactions between dietary elements, their salts, and complexing/binding ligands is vital to manage both deficiency and toxicity associated with essential element bioavailability. Numerous mineral ligands are found in both animal and plant foods and are known to exert bioactivity via element chelation resulting in modulation of antioxidant capacity or micobiome metabolism among other physiological outcomes. However, little is explored in the context of dietary mineral ligands and element bioavailability enhancement, particularly with respect to ligands from plant-derived food sources. This review highlights a novel perspective to consider various plant macro/micronutrients as prospective bioavailability enhancing ligands of three essential elements (Fe, Zn, and Ca). We also delineate the molecular mechanisms of the ligand-binding interactions underlying mineral bioaccessibility at the luminal level. We conclude that despite current understandings of some of the structure–activity relationships associated with strong mineral–ligand binding, the physiological links between ligands as element carriers and uptake at targeted sites throughout the gastrointestinal (GI) tract still require more research. The binding behavior of potential ligands in the human diet should be further elucidated and validated using pharmacokinetic approaches and GI models.     

Improving the functional properties of fish gelatin by conjugation with the water-soluble fraction of bitter almond gum

Food Science and Biotechnology - Maillard-based conjugation may be a useful way of improving the functional properties of food biopolymers. In this study, covalent attachment of fish gelatin (FG)...     

Enhanced piezoelectric properties and temperature stability of Bi4Ti3O12-based Aurivillius ceramics via W/Nb substitution

Bi₄Ti₃O₁₂ (BIT), a typical Aurivillius ceramics with high Curie temperature (T_c ? 675 °C), has great potential for high temperature applications. This work provides an effective method of inducing structure distortion, relieving the tetragonal strain of the TiO₆ octahedron and decreasing the concentration of oxygen vacancies to improve the piezoelectricity and temperature stability of BIT ceramics. Bi₄Ti_2.98W_0.01Nb_0.01O₁₂ possesses an optimum piezoelectric coefficient (d₃₃) of 32 pC/N, a high T_c of 655 °C and a large resistivity of 3 × 10⁶ Ω·cm at 500 °C. The maximum d₃₃ reported here is approximately quadruple than that of pure BIT (?7 pC/N). Moreover, the d₃₃ of W/Nb co-doped BIT and the in-situ temperature stability of the compression-mode sensor present a highly stable characteristic in the range of 25–600 °C. These results imply that W/Nb-modified BIT ceramics is a promising candidate for application at high temperatures of up to 600 °C.     

Interesting magnetic properties observed in the 4f ferromagnet NdRu2

We have investigated dc magnetization, magneto-transport and magnetostriction of C15 Laves phase 4f ferromagnetic compound NdRu₂ as a function of temperature and applied magnetic field. We find that the magnetic properties of this compound can not be explained within a simple model based on localized magnetic moment even though Nd based compounds and alloys are usually considered as localized magnetic moment systems. Our experimental results on temperature dependence of magnetization, electrical resistivity and magnetoresistance suggest the existence of spin fluctuations in the paramagnetic state of NdRu₂. This compound shows unusually high and non-linear forced magnetostriction. We conjecture the hybridization of Nd 4f states with valence electrons as one of the possibilities for explaining the experimental results.     

Crystal structure and thermoelectric properties of Cu2Cd1−xZnxSnSe4 solid solutions

Cu₂Cd_1–xZn_xSnSe₄ solid solutions were synthesized, and their phase constitutions and thermoelectric properties were investigated. The solid solutions crystallized in the stannite-type structure for Zn contents x up to 0.65 and in the kesterite-type structure for 0.7 ≤ x ≤ 1.0. The lattice parameter a and cell volume V of the compounds decreased linearly with increasing x for both the stannite-type (0 ≤ x ≤ 0.65) and the kesterite-type (0.7 ≤ x ≤ 1) structures. The lattice parameter c decreased with increasing x for the compounds with the kesterite-type structure but increased for the compounds with the stannite-type structure. The c/a ratio increased with increasing Zn content, which indicated an weakening of the lattice distortion. The Seebeck coefficient tended to decrease with increasing Zn content, whereas the electrical conductivity and thermal conductivity increased. The figure of merit ZT increased with increasing x over the composition range of 0 ≤ x ≤ 0.60 and then fluctuated with a further increase in x. A maximum ZT of 0.23 was achieved for Cu₂Cd_0.4Zn_0.6SnSe₄ at 720 K.