Consumer purchasing behaviour towards fish and seafood products: patterns and insights from a sample of international studies

The present systematic review was performed to assess consumer purchasing behaviour towards fish and seafood products in the wide context of developed countries. Web of Science, Scopus, ScienceDirect and Google Scholar engines were used to search the existing literature and a total of 49 studies were identified for inclusion. These studies investigated consumer purchasing behaviour towards a variety of fish and seafood products, in different countries and by means of different methodological approaches. In particular, the review identifies and discusses the main drivers and barriers of fish consumption as well as consumers’ preferences about the most relevant attributes of fish and seafood products providing useful insights for both practitioners and policy makers. Finally, main gaps of the existing literature and possible trajectories for future research are also discussed.

Seafood safety and quality: an analysis of the supply chain in the Sultanate of Oman

The globalization of trade in fish has created many challenges for the developing world specifically with regard to food safety and quality. International organisations have established a good basis for standards in international trade. Whilst these requirements are frequently embraced by the major importers (such as Japan, the EU and the USA), they often impose additional safety requirements and regularly identify batches which fail to meet their strict standards. Creating an effective national seafood control system which meets both the internal national needs as well the requirements for the export market can be challenging. Many countries adopt a dual system where seafood products for the major export markets are subject to tight control whilst the majority of the products (whether for the local market or for more regional trade) are less tightly controlled. With regional liberalization also occurring, deciding on appropriate controls is complex. In the Sultanate of Oman, fisheries production is one of the countries' chief sources of economic revenue after oil production and is a major source of the national food supply. In this paper the structure of the fish supply chain has been analysed and highlighted the different routes operating for the different markets. Although much of the fish are consumed within Oman, there is a major export trade to the local regional markets. Much smaller quantities meet the more stringent standards imposed by the major importing countries and exports to these are limited. The paper has considered the development of the Omani fish control system including the key legislative documents and the administrative structures that have been developed. Establishing modern controls which satisfy the demands of the major importers is possible but places additional costs on businesses. Enhanced controls such as HACCP and other management standards are required but can be difficult to justify when alternative markets do not specify these. These enhanced controls do however provide additional consumer protection and can bring benefits to local consumers. The Omani government is attempting to upgrade the system of controls and has made tremendous progress toward the implementation of HACCP and introducing enhanced management systems into its industrial sector. The existence of strengthened legislative and government support, including subsidies, has encouraged some businesses to implement HACCP. The current control systems have been reviewed and a SWOT analysis approach used to identify key factors for their future development. The study shows that seafood products in the supply chain are often exposed to lengthy handling and distribution process before reaching the consumers, a typical issue faced by many developing countries. As seafood products are often perishable, they safety is compromised if not adequately controlled. The enforcement of current food safety laws in the Sultanate of Oman is shared across various government agencies. Consequently, there is a need to harmonize all regulatory requirements, enhancing the domestic food protection and to continue to work towards a fully risk-based approach in order to compete successfully in the global market.

Nitric oxide detection in cell culture exposed to LPS after Er:YAG laser irradiation

P>Aim To evaluate in vitro the effect of calcium hydroxide [Ca(OH)(2)] and Er:YAG laser on bacterial endotoxin [also known as lipopolysaccharide (LPS)] as determined by nitric oxide (NO) detection in J774 murine macrophage cell line culture. Methodology Samples of LPS solution (50 mu gmL-1), Ca(OH)(2) suspension (25 mg mL-1) and LPS suspension with Ca(OH)(2) were prepared. The studied groups were: I - LPS (control); II - LPS + Ca(OH)(2); III - LPS + Er:YAG laser (15 Hz 140 mJ); IV - LPS + Er:YAG laser (15 Hz 200 mJ); V - LPS + Er:YAG laser (15 Hz 250 mJ), VI - Pyrogen-free water; VII - Ca(OH)(2). Murine macrophage J774 cells were plated and 10 mu L of the samples were added to each well. The supernatants were collected for NO detection by the Griess reaction. Data were analysed statistically by one-way anova and Tukey`s test at 5% significance level. Results The mean and SE (in mu mol L-1) values of NO release were: I - 10.48 +/- 0.58, II - 6.41 +/- 0.90, III - 10.2 +/- 0.60, IV - 8.35 +/- 0.40, V - 10.40 +/- 0.53, VI - 3.75 +/- 0.70, VII - 6.44 +/- 0.60; and the values for the same experiment repeated after 1 week were: I - 21.20 +/- 1.50, II - 9.10 +/- 0.60, III - 19.50 +/- 1.00, IV - 18.50 +/- 0.60, V - 21.30 +/- 0.90, VI - 2.00 +/- 0.20, VII - 6.80 +/- 1.70. There was no significant difference (P > 0.05) between the control and the laser-treated groups (III, IV and V), or comparing groups II, VI and VII to each other (P > 0.05). Group I had significantly higher NO release than group II (P < 0.05). Groups II and VI had similar NO release (P > 0.05). Conclusions Calcium hydroxide inactivated the bacterial endotoxin (LPS) whereas none of the Er:YAG laser parameter settings had the same effectiveness.

SEM analysis of enamel surface treated by Er : YAG laser: Influence of irradiation distance

Background: Depending on the distance of laser tip to dental surface a specific morphological pattern should be expected. However, there have been limited reports that correlate the Er:YAG irradiation distance with dental morphology. Purpose: To assess the influence of Er:YAG laser irradiation distance on enamel morphology, by means of scanning electron microscopy (SEM). Methods: Sixty human third molars were employed to obtain discs (congruent to 1 mm thick) that were randomly assigned to six groups (n = 10). Five groups received Er:YAG laser irradiation (80 mJ/2 Hz) for 20 s, according to the irradiation distance: 11, 12, 14, 16, or 17 mm. and the control group was treated with 37% phosphoric acid for 15 s. The laser-irradiated discs were bisected. One hemi-disc was separated for superficial analysis without subsequent acid etching, and the other one, received the phosphoric acid for 15 s. Samples were prepared for SEM. Results: Laser irradiation at 11 and 12 min provided an evident ablation of enamel, with evident fissures and some fused areas. At 14, 16 and 17 mm the superficial topography was flatter than in the other distances. The subsequent acid etching on the lased-surface partially removed the disorganized tissue. Conclusions: Er:YAG laser in defocused mode promoted slight morphological alterations and seems more suitable for enamel conditioning than focused irradiation. The application of phosphoric acid on lased-enamel surface, regardless of the irradiation distance, decreased the superficial irregularities.

Shear strength of the bond to primary dentin: influence of Er:YAG laser irradiation distance

The aim of this study was to assess in vitro the influence of Er:YAG laser irradiation distance on the shear strength of the bond between an adhesive restorative system and primary dentin. A total of 60 crowns of primary molars were embedded in acrylic resin and mechanically ground to expose a flat dentin surface and were randomly assigned to six groups (n = 10). The control group was etched with 37% phosphoric acid. The remaining five groups were irradiated (80 mJ, 2 Hz) at different irradiation distances (11, 12, 16, 17 and 20 mm), followed by acid etching. An adhesive agent (Single Bond) was applied to the bonding sites, and resin cylinders (Filtek Z250) were prepared. The shear bond strength tests were performed in a universal testing machine (0.5 mm/min). Data were submitted to statistical analysis using one-way ANOVA and the Kruskal-Wallis test (p < 0.05). The mean shear bond strengths were: 7.32 +/- 3.83, 5.07 +/- 2.62, 6.49 +/- 1.64, 7.71 +/- 0.66, 7.33 +/- 0.02, and 9.65 +/- 2.41 MPa in the control group and the groups irradiated at 11, 12, 16, 17, and 20 mm, respectively. The differences between the bond strengths in groups II and IV and between the bond strengths in groups II and VI were statistically significant (p < 0.05). Increasing the laser irradiation distance resulted in increasing shear strength of the bond to primary dentin.

Study of DNA damage with a new system for irradiation of samples in a nuclear reactor

In this paper, we report results of a quantitative analysis of the effects of neutrons on DNA, and, specifically, the production of simple and double breaks of plasmid DNA in aqueous solutions with different concentrations of free-radical scavengers. The radiation damage to DNA was evaluated by electrophoresis through agarose gels. The neutron and gamma doses were measured separately with thermoluminescent detectors. In this work, we have also demonstrated usefulness of a new system for positioning and removing samples in channel BH#3 of the IEA-R1 reactor at the Instituto de Pesquisas Energeticas e Nucleares (Brazil) without necessity of interrupting the reactor operation. (C) 2010 Elsevier Ltd. All rights reserved.

Magnetoresistance oscillations in triple quantum wells under microwave irradiation

The interference of magneto-intersubband oscillations and microwave-induced resistance oscillations is studied in high-density triple quantum wells. We give an introduction into magnetotransport in trilayer systems and focus on photoresistance measurements. The power and frequency dependence of the observed magnetoresistance oscillations can be described by the inelastic mechanism of photoresistance, generalized to the three-subband case. (C) 2009 Elsevier B.V. All rights reserved.

MAGNETORESISTANCE OSCILLATIONS IN DOUBLE QUANTUM WELLS UNDER MICROWAVE IRRADIATION

We report in detail oscillatory magnetoresistance in double quantum wells under microwave irradiation. The experimental investigation contains measurements of frequency, power and temperature dependence. In theory, the observed interference oscillations are explained in terms of the influence of subband coupling on the frequency-dependent photoinduced part of the electron distribution function. Thus, the magnetoresistance shows the interference of magneto-intersubband and conventional microwave induced resistance oscillations.

X-ray and gamma irradiation effects on dipole defects in CaF2 : La, Yb, Al

Impurity-interstitial dipoles in calcium fluoride solutions with Al3+, Yb3+ and La3+ fluorides were studied using the thermally stimulated depolarization current (TSDC) technique. The dipolar complexes are formed by substitutional trivalent ions in Ca2+ sites and interstitial fluorine in nearest neighbor sites. The relaxations observed at 150 K are assigned to dipoles nnR(S)(3+)- F-i(-) (R-S = La or Yb). The purpose of this work is to study the processes of energy storage in the fluorides following X-ray and gamma irradiation. Computer modelling techniques are used to obtain the formation energy of dipole defects. (C) 2007 Elsevier Ltd. All rights reserved.

TL dosimetry of natural quartz sensitized by heat-treatment and high dose irradiation

The aim of this paper is to report the sensitization of the TL peak appearing at 270 degrees C in the glow curve of natural quartz by using the combined effect of heat-treatments and irradiation with high gamma doses. For this, thirty discs with 6 x 1 mm(2) were prepared from plates parallell to a rhombolledral crystal face. The specimens were separated into four lots according to its TL read out between 160 and 320 degrees C. One lot was submitted to gamma doses of Co-60 radiation starting at 2 kGy and going up until a cumulative dose of 25 kGy. The other three lots were initially heal-treated at 500, 800 and 1000 degrees C and then irradiated with a single dose of 25kGy. The TL response of each lot was determined as a function of test-doses ranging from 0.1 to 30 mGy. As a result, it was observed that heat-treatments themselves did not produce the strong peak at 270 degrees C that was observed after the administration of high gamma doses. This peak is associated with the optical absorption band appearing at 470 rim which is due to the formation of [AlO4]degrees acting as electron-hole recombination centers. The formation of the 270 degrees C peak was preliminary analyzed in relation to aluminum- and oxygen-vacancy-related centers found in crystalline quartz. (C) 2008 Elsevier Ltd. All rights reserved.

Does the TL supralinearity occur during irradiation in alkali halides?

In the last ten to fifteen years, there has been a predominant belief that the linear-supralinear-sublinear behaviour of the TL response of alkali halides to the radiation dose necessarily occurs in the heating stage for TL reading. It is based on the assumption that coloration in these crystals grows linear-sublinearly with the dose during irradiation. Since both colour centre and TL centre are based on the same point defects the TL response should also grow linear-sublinearly with dose. In 1950, half a dozen authors showed that the coloration of F-centres in KCl takes place in two stages, the second one being responsible for non-linear behaviour. In this paper, we show that indeed in NaCl both F-centre and TL grow linear-supralinear-sublinearly with the dose during irradiation.

Photo-irradiation effects on the surface morphology of poly(p-phenylene vinylene) films

In this work, we have studied the surface morphology of photo-irradiated poly(p-phenylene vinylene) (PPV) thin films by using atomic force microscopy (AFM). We have analyzed the first-order statistical parameters, the height distribution and the distance between selected peaks. The second-order statistical analysis was introduced calculating the auto-covariance function to determine the correlation length between heights. We have observed that the photo-irradiation process produces a surface topology more homogeneous and isotropic such as a normal surface. In addition, the polymer surface irradiation can be used as a new methodology to obtain materials optically modified. (C) 2009 Elsevier B.V. All rights reserved.

Histological analyses of thermal effect caused by 1.2 W diode laser irradiation at rat periodontal pockets

The aim of this in vivo study was to evaluate the thermal effects caused by 810 nm 1.2 W diode laser irradiation of periodontal tissues. Despite all data available concerning the laser application for periodontal treatment, one of the most relevant challenges is to prevent the harmful tissue heating induced by different clinical protocols. Periodontal pockets were induced at molars in 96 rats. Several irradiation powers under CW mode were investigated: 0, 400, 600, 800, 1000, 1200 mW. The pockets were irradiated using a 300 A mu m frontal illumination fiber. The animals were killed at 4 or 10 days after irradiation. The mandible was surgically removed and histologically processed. The histological sections stained with H/E demonstrated that irradiation parameters up to 1000 mW were thermally safe for the periodontal tissues. The sections stained with Brown & Brenn technique evidenced bacteria in the periodontal tissues. Consequently, the diode laser irradiation as a unique treatment was not capable to eliminate bacteria of the biofilm present in the pockets. According to the methodology used here, it was concluded that the thermal variation promoted by a diode laser can cause damage to periodontal tissues depending on the energy density used. The 1.2 W diode laser irradiation itself does not control the bacteria present in the biofilm of the periodontal pockets without mechanical action. The knowledge of proper high intensity laser parameters and methods of irradiation for periodontal protocols may prevent any undesirable thermal damage to the tissues.

Effect of power densities and irradiation times on the degree of conversion and temperature increase of a microhybrid dental composite resin

The different parameters used for the photoactivation process provide changes in the degree of conversion (DC%) and temperature rise (TR) of the composite resins. Thus, the purpose of this study was to evaluate the DC (%) and TR of the microhybrid composite resin photoactivated by a new generation LED. For the KBr pellet technique, the composite resin was placed into a metallic mould (1-mm thickness and 4-mm diameter) and photoactivated as follows: continuous LED LCU with different power density values (50-1000 mW/cm(2)). The measurements for the DC (%) were made in a FTIR Spectrometer Bomen (model MB-102, Quebec-Canada). The spectroscopy (FTIR) spectra for both uncured and cured samples were analyzed using an accessory for the diffuse reflectance. The measurements were recorded in the absorbance operating under the following conditions: 32 scans, 4-cm(-1) resolution, and a 300 to 4000-cm(-1) wavelength. The percentage of unreacted carbon-carbon double bonds (% C=C) was determined from the ratio of the absorbance intensities of aliphatic C=C (peak at 1638 cm(-1)) against an internal standard before and after the curing of the specimen: aromatic C-C (peak at 1608 cm-1). For the TR, the samples were made in a metallic mould (2-mm thickness and 4-mm diameter) and photoactivated during 5, 10, and 20 s. The thermocouple was attached to the multimeter to allow the temperature readings. The DC (%) and TR were calculated by the standard technique and submitted to ANOVA and Tukey`s test (p < 0.05). The degree of conversion values varied from 35.0 (+/- 1.3) to 45.0 (+/- 2.4) for 5 s, 45.0 (+/- 1.3) to 55.0 (+/- 2.4) for 10 s, and 47.0 (+/- 1.3) to 52.0 (+/- 2.4) for 20 s. For the TR, the values ranged from 0.3 (+/- 0.01) to 5.4 (+/- 0.11)degrees C for 5 s, from 0.5 (+/- 0.02) to 9.3 (+/- 0.28)degrees C for 10 s, and from 1.0 (+/- 0.06) to 15.0 (+/- 0.95)degrees C for 20 s. The power densities and irradiation times showed a significant effect on the degree of conversion and temperature rise.

Surface modification and crystallization of the BaO-B2O3-SiO2 glassy system using CO2 laser irradiation

The surface modification and crystallization process of BaO-B2O3-SiO2 glass compositions when exposed to CO2 laser irradiation was evaluated as a function of the laser power, irradiation time and surface condition. The glass surface was modified by the application of laser power exceeding 0.40 W and an irradiation time of more than 300 s. Micro-Raman and X-ray diffraction measurements revealed at high laser power the formation of beta-BaB2O4 (beta-BBO) crystalline phase. The crystallization of the irradiated region was enhanced when beta-BBO micrometer sized particles were dispersed on the surface of the glass sample. The intensity of the second harmonic generation observed in the crystallized region was found to depend mainly on the condition of the glassy surface prior to glass irradiation. (C) 2007 Elsevier B.V. All rights reserved.