Effectiveness and quality evaluation of electrical stunning versus chilling in Norway lobsters (Nephrops norvegicus)

In the last decade, public interest in the welfare of decapod crustaceans has increased in many parts of the world. This has led to changes in legislation on methods for slaughter in a number of countries, while in others pressure for regulation changes is growing. Electro-stunning may have the potential for reducing noxious stimuli experienced by crustaceans during slaughter. However, data on activity in the central nervous system (CNS) and product quality-related data (indicative of consumer acceptability) are not available for most of the important decapod crustaceans, including the commercially valuable Norway lobster, Nephrops norvegicus. In this study, recordings of nerve activity showed that electro-stunning can render N. norvegicus rapidly insensible qualifying it as a potential humane slaughter procedure. In contrast, placing lobsters on ice for 30 min did not suppress neural activity. In terms of subsequent shelf life, results at day 7 based on QIM, total bacteria counts, H2S-producing bacteria, muscle pH, TMA and biogenic amines indicate no significant differences between the methods of stunning. From a quality perspective, electro-stunning did shorten the period that the product would be considered fresh (higher K-values up to day 5) and triggered faster melanosis development in the cephalothorax, an effect possibly linked to the increased temperature recorded in this area due to the imposed electrical current. However, no significant differences were detected on the cooked products by a trained sensory taste panel. While shelf life is not affected by the electro-stunning process, care should nevertheless be taken to avoid melanosis development, and the consumer perception of freshness in electro-stunned product should be studied further

Low-Temperature Processed TiOx/Zn1−xCdxS Nanocomposite for Efficient MAPbIxCl1−x Perovskite and PCDTBT:PC70BM Polymer Solar Cells

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).The majority of high-performance perovskite and polymer solar cells consist of a TiO2 electron transport layer (ETL) processed at a high temperature (>450 °C). Here, we demonstrate that low-temperature (80 °C) ETL thin film of TiOx:Zn1−xCdxS can be used as an effective ETL and its band energy can be tuned by varying the TiOx:Zn1−xCdxS ratio. At the optimal ratio of 50:50 (vol%), the MAPbIxCl1−x perovskite and PCBTBT:PC70BM polymer solar cells achieved 9.79% and 4.95%, respectively. Morphological and optoelectronic analyses showed that tailoring band edges and homogeneous distribution of the local surface charges could improve the solar cells efficiency by more than 2%. We proposed a plausible mechanism to rationalize the variation in morphology and band energy of the ETL

Phase behaviour and gravity-directed self assembly of hard convex spherical caps

We investigate the phase behaviour and self-assembly of convex spherical caps using Monte Carlo simulations. This model is used to represent the main features observed in experimental colloidal particles with mushroom-cap shape [Riley et al., Langmuir, 2010, 26, 1648]. The geometry of this non-centrosymmetric convex model is fully characterized by the aspect ratio χ∗ defined as the spherical cap height to diameter ratio. We use NPT Monte Carlo simulations combined with free energy calculations to determine the most stable crystal structures and the phase behaviour of convex spherical caps with different aspect ratios. We find a variety of crystal structures at each aspect ratio, including plastic and dimer-based crystals; small differences in chemical potential between the structures with similar morphology suggest that convex spherical caps have the tendency to form polycrystalline phases rather than crystallising into a single uniform structure. With the exception of plastic crystals observed at large aspect ratios (χ∗ > 0.75), crystallisation kinetics seem to be too slow, hindering the spontaneous formation of ordered structures. As an alternative, we also present a study of directing the self-assembly of convex spherical caps via sedimentation onto solid substrates. This study contributes to show how small changes to particle shape can significantly alter the self-assembly of crystal structures, and how a simple gravity field and a template can substantially enhance the process

ASSEMBLY OF COLLOIDAL MESOPHASES AND SUBSTITUTIONALLY DISORDERED PHASES FOR PHOTONICS

Colloidal mesophases are materials that exhibit spontaneous ordering with characteristics between those of crystalline and glassy photonic solids. The study of these partial order photonic mesophases is critical to advancing a new paradigm for photonic structures, with large photonic band gap and negative refraction properties that can be realized via low cost self-assembly. It is well known that photonic crystals dramatically alter the dispersion relations and the spatial power distribution of electromagnetic modes in dielectric materials with a periodic refractive index. Photonic glasses provide control over light diffusion via the optical resonances of building blocks with short-range positional order. New concepts suggest certain types of disorder support photonic band gap properties. This behavior has been predicted in arrangements whose structure factor S(k) tends toward zero as |k| approaches zero including hyperuniform disordered, quasicrystals, and semi-regular tilings. The substitutionally disordered shape-binary phases and single component mesophases, which are the subject of this work, satisfy the structure factor criteria for bandgap formation and their study lies at the frontier of manipulating disorder for colloid-based photonics. Shape-binary mixtures of spheres and peanut-shaped particles (spheres and cut-spheres) are self-organized into substitutionally disordered phases using wedge-cell confinement. The particles are compatible with lobes sizes within ten percent of each other. Particle shape templates are sacrificed to obtain hollow silica shells. This design minimizes segregation between the two particle shape populations by reducing density mismatch. Using fast confocal microscopy, five distinct phases are found between one and two integral layers for the mixture of spheres and peanut-shaped particles: 1(hexagonal) 1β (buckled) 2•(square) 2I (hexagonal) 2II (hexagonal). This sequence is similar to that of single component hard spheres and hard dimers with the addition of major axis orientations for the dimers. For the mixture of spheres and cut-spheres, eight distinct phases are observed: 1_r (hexagonal) 1S_I (side) 1S_II (rotator) 1B (buckled) 2• (square) 2_r (hexagonal) 2S_I (side) 2S_II (rotator). The descriptive sequence is similar to that of pure cut-spheres. The substitutional disorder follows from the Hume-Rothery rules for atomic isomorphous phases. Monte Carlo simulations establish the ideal phases and the phase diagram for the pure dimers and shape mixtures

HOUSEKEEPING GENES ANALYSIS OF FOODBORNE PATHOGENIC BACTERIA Vibrio parahaemolyticus ISOLATED FROM AQUATIC BIRDS IN THAILAND

Background: Vibrio parahaemolyticus is one of the leading causative agent of foodborne disease. Infection is caused by consumption of undercooked contaminated seafood. V. parahaemolyticus is commonly found in crustacean species and marine environment. Presence of this organism in avian host has been previously reported, however genetic analysis of avian V. parahaemolyticus is required for molecular epidemiological study of this organism. The aim of this study was to determine genetic profile of V. parahaemolyticus isolated from fecal aquatic bird samples by modified Multilocus Sequence Typing (MLST) method. Methods: Three housekeeping genes fragments (dnaE, gyrB and pntA) of total 18 V. parahaemolyticus isolates from fecal aquatic bird samples at Bangpoo resort, Samut Prakarn province, Thailand, during 2016-2017, were amplified by using conventional PCR for nucleotide sequencing. Nucleotide sequences were analyzed and phylogenetic tree were constructed by MEGA 7.0 software. Comparative genetic analysis of avian isolates from Thailand and worldwide isolates were performed by using information from MLST database of V. parahaemolyticus ( https://pubmlst.org /vparahaemolyticus/). Results: Three housekeeping genes of 18 isolates were successfully amplified and purified for nucleotide sequencing. Phylogenetic tree analysis of concatenated nucleotide sequences indicated that 18 Thai avian isolates were genetically diverse. Five isolates (MUVP 9, 11, 22, 23 and 24) represented identical genetic profile with clinical isolates from China, India, Japan and Peru. Other examined isolates were closely related to environmental isolates from China and United Kingdom. These resultsshowed that aquatic birds are natural reservoir of V. parahaemolyticus strains with multiple genetic background. Conclusion: This study indicated that aquatic birds possessed potentially pathogenic V. parahaemolyticus and may play a role in transmission of this organism across the countries. &nbsp

Anti-Icing Property of Superhydrophobic Nanostructured Brass via Deposition of Silica Nanoparticles and Nanolaser Treatment

Ice accumulation on brass surfaces can lead to heat transfer inefficiency, equipment degradation, and potential accidents. To address this issue, superhydrophobic surface technology is utilized. This work aims to develop superhydrophobic nanostructured brass surfaces using the combination of nanolaser ablation and the deposition of silica nanoparticles to achieve the anti-icing property. Four distinct types of brass surfaces namely, the bare surface (BS), the lasered surface (LS), the coated surface (CS), and the coated-lasered surface (CLS) were prepared. The anti-icing performances of the fabricated samples including the effects of the surface structure, the droplet size, and the surface temperature were investigated and evaluated. The results showed that the delayed icing time increased with the increases in the apparent contact angle, the droplet size, and the surface temperature. When the apparent contact angle increased, the contact area between the droplet and the cooling substrate reduced, leading to the longer delayed icing time. With the deposition of silica nanoparticles and nanolaser treatment, CLS achieved the greatest apparent contact angle of 164.5°, resulting in the longest delayed icing time under all experimental conditions. The longest delayed icing time on CLS recorded in this study was 2584 s, which was 575%, 356%, and 27% greater than those on BS, LS, and CS, respectively. The study also revealed that the surface structure played a more crucial role in achieving the anti-icing property when compared to the surface temperature or the droplet size. The shortest delayed icing time on CLS at the lowest surface temperature and at the smallest droplet size was longer than those on BS and LS at all conditions. The results were also discussed in relation to a heat transfer model. The findings of this research can serve as an avenue for advancing knowledge on heat transfer enhancement and energy efficiency