Self-organization processes in semiconductor under photo-induced Gunn effect

Theoretical investigation of self-organization of non-equilibrium carriers system in n-GaAs under photo-stimulated Gunn effect was performed. It was shown that the behavior of carrier system could be controlled using incident light intensity resulting in different oscillation regimes. Results obtained allow us to predict application ranges for devices working on the phenomena investigated.     

Enhancement of safety and quality of ready-to-cook Asian green mussel using acidic electrolyzed water depuration in combination with sous vide cooking

Emerging technologies were combined to ensure the safety for consumers of Asian green mussel (AGM; Perna viridis). The combination of acidic electrolyzed water (AEW) depuration and sous vide cooking effectively reduced Vibrios while maintaining the quality of mussel. The use of AEW depuration combined with sous vide cooking at 100 °C for 1 min (D/SV-1) provided the yield of mussel meat of 27.22%, maintained the color, and texture properties. It could prevent the oxidation of polyunsaturated fatty acids and caused no changes in patterns of main proteins including paramyosin, actin and tropomyosin. Vibrio parahaemolyticus, V. vulnificus and Shewanella algae in AGM without treatment were 4.12, 3.00 and 3.30 log₁₀ CFU/g, respectively. Those bacterial species were confirmed by MALDI Biotyper® technique. They were potentially inactivated by the selected process. In addition, the next generation sequencing (NGS) based on the 16S rRNA gene revealed a low percentage of V. vulnificus genome (2.72%) and the complete elimination of other naturally existing Vibrios. Overall, AEW depuration of raw mussels, followed by sous vide cooking could be a promising method for the production of safe ready-to-cook Asian green mussels for consumption.Industry relevanceCommon Asian green mussel (AGM; Perna viridis) may represent a risk for public health associated with pathogenic bacteria originating from the aquatic environment. It also deteriorates rapidly within 1–2 days because of its perishable nature, thus losing its market value. To tackle such problems, appropriate pretreatment using acidic electrolyzed water depuration, followed by sous vide cooking under proper conditions could be implemented for safety assurance of ready-to-cook AGM by eliminating both pathogenic and spoilage bacteria. Also, the eating quality could be maintained. As a consequence, the technology developed in the present study could offer an effective solution for ensuring customer safety without compromising eating quality. It could be commercially employed for seafood processing industry, especially for bivalve mollusks, e.g., mussels, scallops, and clams.     

Hydrazine hydrate-induced hydrothermal synthesis of MnFe2O4 nanoparticles dispersed on graphene as high-performance anode material for lithium ion batteries

Herein, a MnFe₂O₄/graphene (MnFe₂O₄/G) nanocomposite has been synthesized via a facile N₂H₄·H₂O-induced hydrothermal method. During the synthesis, N₂H₄·H₂O is employed to not only reduce graphene oxide to graphene, but also prevent the oxidation of Mn²⁺ in alkaline aqueous solution, thus ensuring the formation of MnFe₂O₄/G. Moreover, MnFe₂O₄ nanoparticles (5–20 nm) are uniformly anchored on graphene. MnFe₂O₄/G electrode delivers a large reversible capacity of 768 mA h g⁻¹ at 1 A g⁻¹ after 200 cycles and high rate capability of 517 mA h g⁻¹ at 5 A g⁻¹. MnFe₂O₄/G holds great promise as anode material in practical applications due to the outstanding electrochemical performance combined with the facile synthesis strategy.     

Air-breathing bio-cathodes based on electro-active biochar from pyrolysis of Giant Cane stalks

An innovative low-tech solution to fabricate electro-active biochar (e-biochar) electrodes for bio-electrochemical systems (BES) is proposed. Ligno-cellulosic stalks of Giant Cane (Arundo Donax L.) were subjected to pyrolysis treatment at 900 °C for 1 h. The material kept its original hollow cylindrical shape, rigid morphology and porous texture, as confirmed by 3DX-ray micro-computed tomography. These characteristics are suitable for its use at the air-water interface in BES, as air-breathing bio-cathodes. BET (Brunauer-Emmett-Teller) specific surface area was equal to 114 ± 4 m² g⁻¹, with more than 95% of pores in the microporosity range (pore diameter < 1 nm). Surface electrocatalytic activity was sufficient to sustain oxygen reduction reaction at pH 7, in terms of both onset potential (−0.02 V vs Ag/AgCl) and reduction limiting current density (1 A m⁻²). Electrical resistivity measurements confirmed sufficient conductivity (8.9 × 10⁻³ ± 1 × 10⁻⁴ Ω m) of the material and Raman spectroscopy allowed to estimate a graphitization degree in relation to the I_D/I_G, equal to 2.26. In parallel, the e-biochar were tested as air-exposed bio-cathodes in BES, coupled to carbon cloth bio-anodes. After inoculation with wastewater from swine-farming, current densities were generated in the range of 100–150 mA m⁻², along more than 2 months of operation, under sodium acetate feeding. Confocal laser scanning imaging revealed consistent biofilm formation on the water-side surface of the cathodes, while a nearly-complete absence of it at the air-side.These e-biochar electrodes might open innovative perspectives to scale-up BES for different applications. Here, consistent salts depositions on the material after 70 days of exposure to the wastewater, suggest that e-biochar biocathodes might serve to recycle nutrients to agricultural soils, through minerals-enriched biochar.     

An immunoassay for ochratoxin A without the mycotoxin

Phage display peptide libraries allow the selection of new molecules capable of mimicking the structural and functional features of native proteins or chemicals. This technology can be applied to developing new reagents, which may serve as the surrogate of the original objects. In order to screen peptides capable of mimicking ochratoxin A (OTA) in the interaction with anti-OTA monoclonal antibody (McAb) and establish the immunoassay for OTA, an anti-OTA McAb was used as the target for panning-elution selection from a phage random seven-peptide library. After four rounds of panning, 11 phages were found to be able to mimic OTA in binding with the antibody. Enzyme-linked Immunosorbent Assay (ELISA) for detecting OTA was established with the phages. In the most sensitive assay, the linear range of the inhibition curve was 200–8000 pg/ml; the detection limit was 150 pg/ml. The inserted peptide sequences were deduced by DNA sequencing. The common amino acid residue sequence was IR(V)PMV(L)XX (X is any amino acid residues), which was verified by two synthesized peptides. The results demonstrated that those phage peptides could be used as the surrogate of OTA to establish the immunoassay.     

Occurrence of deoxynivalenol (vomitoxin) in beer in Turkey detected by HPLC

The objective of this study was to investigate the deoxynivalenol (DON) contamination/level in beer consumed Turkey using high performance liquid chromatography (HPLC) with UV–visible detector at 220 nm. An acetonitrile–water (21 + 4, v/v) extract of samples first was cleaned up on a column packed with alumina–celite–charcoal (0.50 g + 0.25 g + 0.60 g) and the cartridge was washed with acetonitrile–water (21 + 4, v/v) for column condition and C₁₈ solid-phase extraction column was used for second clean up. The minimum detectable amount for the DON was 125 μg/l (2.5 ng injected). A total of 50 commercially available beer samples, collected from markets. None of the samples contained any detectable amount of DON. The recoveries for beer with the known amounts of DON (1 ppm) were 83.2% (SD 5.44, n = 5). This is a pioneering study performed in beer samples consumed in Turkey for the presence of DON.     

Determination of lactoferrin in bovine milk,colostrum and infant formulas by optical biosensor analysis

An automated, rapid, sensitive and label-free biosensor-based immunoassay for lactoferrin in bovine milk utilising surface plasmon resonance (SPR) optical detection is described. Lactoferrin content is estimated from its specific interaction with an anti-bovine lactoferrin antibody immobilised on the sensor surface in a direct- binding assay format. Samples are prepared for analysis by direct dilution into buffer. Analysis conditions, including ligand immobilisation, flow-rate, contact time and regeneration have been defined and non-specific binding considerations evaluated. Performance parameters include a working range of 0–1000 ng mL⁻¹, a method-detection limit of 19.9 μg mL⁻¹ in undiluted milk, overall instrument response RSD_R of 3.50%, a mean inter-assay RSD_R of 10.8% for milk and surface stability over ca 500 samples. The technique was applied to the measurement of lactoferrin content of consumer milks, colostrum and infant formulas, and temporal change during early bovine lactation.     

热风干燥和微波干燥对草鱼肉品质的影响

目的 研究微波干燥和热风干燥对草鱼片品质的影响。方法 采用50℃热风干燥和400 W微波干燥对草鱼片进行干燥, 对草鱼片干燥过程中水分含量、质构、色度、脂肪及蛋白质相对含量等进行表征。借助气相色谱-质谱法(gas chromatography-mass spectrometry, GC-MS)研究不同干燥条件对草鱼片挥发性物质的影响。结果 两种干燥过程中草鱼片水分含量下降, 硬度增加, 亮度降低, 同时鱼肉蛋白质和脂肪的相对湿基含量增加。其中, 热风干燥时间6~8 h, 微波干燥时间4~5 min的草鱼片硬度和咀嚼性较大、弹性适中、红度值(a*)较大。两种干燥方式中草鱼片挥发性物质的种类和含量均增加, 微波干燥和热风干燥共分别检出52种和36种挥发性物质。微波干燥产生了较多的醛类、不饱和醇类、酮类物质, 对鱼肉风味有较大影响。结论 400 W微波干燥较50℃热风干燥更适用于实际加工过程中的快速干燥工艺, 且能够较好的改善鱼肉风味。     

Functional gels from bovine blood proteins as fat substitutes and potential carriers of heme iron

We evaluated technological and physicochemical properties and infrared spectra of heat-induced hydrogels (HGs) and emulgels (EGs) obtained from a composite gellant (DFM) of freeze-dried bovine plasma and red cell fraction. Results showed that 10% W/W of DFM is enough to produce gels of adequate self-support, with syneresis ranging from 3 to 11% and 6–13%, for HGs and EGs, respectively. The color differences were perceptible in all cases, and the opacity related to the assembly of the networks increased with the amount of DMF in both gels. Heat-induced gelation led to heme iron (HFe) retention efficiency higher than 89.45 ± 0.19%. Also, lipid oxidation levels in the EGs were lower than the threshold value. We concluded that 10% of DMF allowed obtaining appropriate gels for their use as fat substitutes and potential heme iron vehicles in food products. However, bioavailability studies are required to better understand their behavior under digestive conditions.Industrial relevanceCurrently, a low proportion of slaughterhouse blood is aimed at human consumption. Plasma is the most widely used fraction of bovine blood, while the red cell fraction has little application for human consumption, despite its incredible nutritional value. Therefore, the results of this study represent a promising alternative for the use of the red cell fraction, which could be applied to the preparation of highly absorbed iron-enriched foods, useful in the prevention or treatment of iron-deficiency anemia. The iron-enriched gels of our study could be used as fat substitutes in the design of low-fat or improved lipid-profile food matrixes (including baked goods and meat products), which implies adding value to a by-product of slaughterhouses and a potential benefit for the industry of reformulated food products.