Search Results (105)

Fish are nutritionally valuable foods but are also highly perishable, representing a major research focus for the development of effective preservation strategies to delay spoilage while maintaining microbiological acceptability. In this context, edible coatings have gained increasing attention as clean-label tools to extend the shelf life of perishable foods. In this study, an alginate-based emulsion containing oregano essential oil (OEO) was applied to commercial frozen–thawed ready-to-cook (RTC) hake fillets, intentionally selected as a reproducible model system to evaluate coating performance under refrigerated conditions. Coated and uncoated fillets, stored at 4 °C for up to 7 days, were monitored over time for microbiological and physicochemical parameters, including microbial loads, pH, weight loss, and lipid oxidation (TBARS). Compared to uncoated samples, fillets treated with the alginate–OEO emulsion exhibited a marked delay in spoilage-related microbial growth, with a consistent inhibition of Pseudomonas spp. throughout the experimental period, while maintaining microbiological acceptability. Emulsion-based coated fillets also exhibited reduced lipid oxidation, a more uniform surface appearance with only minor visible color changes, and the absence of unpleasant off odors during the refrigerated storage. Overall, the results demonstrate that the alginate–OEO coating could represent an effective strategy for improving the microbiological and oxidative stability of RTC fish fillets under refrigerated conditions, with potential implications for extended shelf life and a reduction in food waste. Full article

In this study, hydroxyapatite (HAp) was obtained from fishbones of four species: gilt-head bream (Sparus aurata), salmon (Salmo salar), hake (Merluccius merluccius), and megrim (Lepidorhombus boscii). Batch adsorption experiments were performed with Cr³⁺, Ni²⁺, and Zn²⁺ ions under different pH conditions (natural, 3, and 11) and contact times (6 and 72 h), which is innovative in this study and allows a unified comparison across species and thermal treatment (non-calcined vs. calcined). Results indicated that non-calcinated materials were particularly effective for Ni²⁺ and Zn²⁺ removal at natural and acidic pH, whereas calcinated samples were more suitable for Cr³⁺ adsorption under alkaline conditions. Given the precipitation of its insoluble hydroxide under alkaline conditions, zinc removal was limited to natural and acidic pH. Among the tested precursors, megrim and hake-derived (non-calcined) HAp exhibited the highest performance, achieving up to 99.99% removal efficiency at 6 h of contact time and 20 °C. The analysis of the used adsorbents confirmed metal incorporation into the HAp lattice with minimal crystallographic disruption. These findings demonstrate the potential of fishbone-derived HAp as an efficient and low-cost adsorbent for heavy metal removal from aqueous systems, while simultaneously contributing to the valorization of fishery waste. Full article

Engineering laboratory courses are essential for developing conceptual understanding and practical skills; however, the time students spend assembling prototypes and troubleshooting wiring issues often reduces opportunities for analysis, programming, and reflective learning. To address this limitation, this study designed and evaluated an integrated STM32-based educational laboratory that consolidates the main peripherals required in a microcontroller course into a single Printed Circuit Board (PCB) platform. A quasi-experimental intervention was implemented with 40 engineering students divided into a control group using traditional STM32 Blue Pill and breadboard connections and an experimental group using the integrated platform. Throughout ten laboratory sessions, data were collected through pre- and post-tests, laboratory logs, and the Motivated Strategies for Learning Questionnaire Short Form (MSLQ-SF). Results showed that the experimental group achieved a Hake normalized learning gain of 40.09% compared with 16.22% in the control group, also showing that it completed the sessions an average of 27 min faster and facilitated a substantial reduction in hardware- and connection-related errors. Significant improvements were also observed in metacognitive and improved motivational and self-regulated learning scores. Overall, the findings indicate that reducing operational barriers in laboratory work enhances both cognitive and motivational learning processes, supporting the adoption of integrated educational hardware to optimize learning outcomes in engineering laboratory courses. Full article

In 2020, a dairy farm in northwest Germany reported several cows with severe respiratory disease, fever, and reduced milk production. Multiple direct and indirect diagnostic methods were used to identify the cause of the disease. However, the pathogens detected could not be correlated with the severity of the clinical symptoms, so further diagnostic steps were taken. Blood and nasal swab samples were examined using next-generation sequencing (NGS) as part of a metagenomic analysis. For the first time in Germany, Hepacivirus bovis genotype 2 was detected. Real-time RT-PCR assays confirmed the presence of BovHepV genotypes 1 and 2 in the herd between 2020 and 2023. Analyses of complete and partial genome sequences demonstrated the presence of different virus variants in the herd over several years. In addition, the sequence data indicated that cattle can be reinfected with viruses belonging either to different BovHepV subtypes or to the same subtype. Although no direct link could be established between the detection of bovine hepaciviruses and the observed clinical symptoms, the PCR and sequence data obtained provide valuable insights into the epidemiology and pathogenesis of BovHepV infections. Full article

This study examines the impact of a Science–Technology–Society–Environment (STSE) educational intervention on the teaching of acid–base reactions to 11th-grade students (n = 17). The didactic sequence combined laboratory experiments, real-data analysis, and an interdisciplinary role-play debate, designed to connect chemical concepts with pressing socio-environmental challenges such as ocean acidification, acid rain, and acid mine drainage. Data collection included a pre- and post-test on environmental awareness and semi-structured interviews, enabling the assessment of both conceptual learning and attitudinal change. Significant conceptual gains were observed, with five of eleven test items reaching a normalized Hake gain ≥ 0.70, alongside increased environmental awareness. Qualitative findings further revealed that students valued the real-world context and interdisciplinary integration, reporting enhanced motivation, civic responsibility, and a more meaningful engagement with science. Overall, the results suggest that STSE-based chemistry instruction not only strengthens students’ understanding of acid–base equilibria but also fosters sustainability competencies essential for responsible and informed citizenship in the 21st century. Full article

Opioid overdoses in the United States remain a significant public health concern. Opioid use disorder (OUD) is stigmatized, exacerbating negative health outcomes. Reducing stigma in healthcare, including in pharmacies, is critical. The “Let’s Talk Stigma” program was collaboratively developed with two schools of pharmacy, a local health department, and individuals with lived drug use experience. It aimed to reduce OUD-related stigma among pharmacists, pharmacy technicians, student pharmacists, and other allied health professionals. The program included six core components: a podcast, continuing education, a standardized curriculum for student pharmacists, training for pharmacy technicians and medical assistants, pharmacy outreach by student pharmacists, and partnerships with chain pharmacies. The anti-stigma podcast reached a global audience with nearly 22,000 listens, while local sessions engaged over 5000 individuals. These initiatives were integrated into Doctor of Pharmacy curricula, with student pharmacists distributing stigma-reduction kits in local pharmacies. A mixed-methods approach, incorporating qualitative data from participant reflections and quantitative data from surveys, podcast analytics, and attendance records, was used for program evaluation. Participants reported increased awareness of stigma, improved attitudes, and greater professional responsibility to reduce stigma. The program successfully leveraged partnerships, flexible delivery methods, and inclusion of people with lived drug use experience in its design. Full article

The high incidence of anthropogenic impacts in the Mediterranean basin raises concerns on the health and quality of commercial fish species. This study aims to evaluate the health status of the European hake, Merluccius merluccius, from three areas of the Catalan coast (NW Mediterranean Sea) with different anthropogenic impacts (i.e., chemical pollution, litter, …) and assess if hake could serve as a sentinel species. We measured biomarkers of chemical exposure including B-esterases, antioxidant enzymes (GST, GR, GPx, CAT), biotransformation markers (EROD), lipid peroxidation, and macro-parasite assemblages. Hake showed, generally, a good health status across all areas with homogeneous patterns for most parameters. Tissue-specific differences included elevated gonadal cholinesterases and higher brain and hepatic carboxylesterase activities in the south, and increased hepatic EROD but lower lipid peroxidation in the central Barcelona area. Parasite assemblages were dominated by Digenea, Cestoda, and Nematoda, with higher cestode prevalence in both central and south zones. In summary, despite a greater prevalence of environmental pollution in the central region, there was a homogeneous pattern in hake health indicators throughout the three studied fishing zones. These results establish a baseline for hake health in Mediterranean waters and suggest that the species’ high mobility and wide depth range may limit its utility to detect local-scale pollution impacts, though it may serve as a regional-scale bioindicator. Full article

Germ cell xenotransplantation is a promising tool for enhancing aquaculture production and supporting the conservation of declining fish species. A major limitation is the reliable identification of germ stem cells, which remains challenging due to the scarcity of validated molecular markers. This study assessed the suitability of different immunohistochemical approaches for identifying ovarian germ stem cells (OGSCs) in three Mediterranean species of commercial interest: European hake (Merluccius merluccius), meagre (Argyrosomus regius), and flathead grey mullet (Mugil cephalus). Among the antibodies tested (anti-OCT4, anti-VASA, anti-Sox2), only anti-VASA and anti-Sox2 labeled cells with morphological features consistent with OGSCs, although staining intensity, specificity, and cross-reactivity with early oocytes varied across species. In parallel, preliminary protocols for OGSC isolation and in vitro proliferation were developed for European hake and meagre. Enzymatic dissociation with collagenase, followed by Ficoll-Paque density separation and culture in Leibovitz’s L-15 medium supplemented with 2% fetal bovine serum at 25 °C, resulted in the highest OGSC recovery and detectable increases in proliferating cells. A sequential pre-plating step enhanced enrichment in meagre but caused substantial cell loss in hake. Overall, this study provides a comparative evaluation of female germline stem cell markers in these species, contributing to future surrogate reproduction and germplasm conservation strategies. Full article

Accurate determination of the target strength (TS) of a fish species is essential for estimating the biomass of fish stocks using acoustic technology. This study estimated the daytime in situ target strength of Pacific hake (Merluccius productus) at 38 kHz using echosounder data collected during hake biomass acoustic-trawl surveys and research cruises conducted from 2009 to 2019 by U.S. and Canadian scientists. The intercept term for the 20-log TS regression over fish length at 38 kHz, $b_{20}$ was found to be −67.9 dB re 1 m² (CI: −68.09, −67.72), closely aligning with the currently used value of −68 dB in biomass assessments. Applying the revised $b_{20}$ value of −67.9 dB in past stock assessments suggests that biomass estimates would be underestimated by less than 3%, which is well within the typical uncertainty range of fish stock assessments. Full article

The shelf life of perishable foods is traditionally determined by microbiological, chemical, and sensory analyses, which are well-established and reliable. However, these methods can be time-consuming and resource-intensive, and they may not fully account for unexpected storage deviations, such as temperature fluctuations or equipment failures. Smart films emerge as a promising alternative, enabling rapid, visual, and low-cost food quality monitoring. This study developed smart films based on zein/gelatin/cellulose nanocrystals (Z/G/CNC) functionalized with alizarin (AL, 0–3% w/w), produced by casting (12.5% zein, 12.5% gelatin, and 5% CNC w/w). The films were characterized for morphological, physicochemical, thermal, and spectroscopic properties, chromatic response at pH 3–11, activity against Escherichia coli and Staphylococcus aureus, and applicability in monitoring Merluccid hake fillets. The incorporation of AL reduced water solubility, increased water vapor permeability and contact angle, imparted a more intense orange coloration, and improved thermal resistance. AL also increased thickness and elongation at break while reducing tensile strength and Young’s modulus. All films exhibited excellent UV-blocking capacity (<1% transmittance). Noticeable color changes were observed, with the Z/G/CNC/AL1 film being the most sensitive to pH variations. During Merluccid hake storage, ΔE values exceeded 3 within 72 h, with a color change from orange to purple, correlating with fillet pH (8.14) and total volatile basic nitrogen (TVB-N) (24.73 mg/100 g). These findings demonstrate the potential of the developed films as biodegradable sensors for smart packaging of perishable foods. Full article

The present study reports the outcome of an experimental study of organic vapor trailing edge flows. As a working fluid, the organic vapor Novec 649 was used under representative pressure and temperature conditions for organic Rankine cycle (ORC) turbine applications characterized by values of the fundamental derivative of gas dynamics below unity. An idealized vane configuration was placed in the test section of a closed-loop organic vapor wind tunnel. The effect of the Reynolds number was assessed independently from the Mach number by charging the closed wind tunnel. The airfoil surface roughness and the trailing edge shape were evaluated by experimenting with different test blades. The flow and the loss behavior were obtained using Pitot probes, static wall pressure taps, and background-oriented schlieren (BOS) optics. Isentropic exit Mach numbers up to 1.5 were investigated. Features predicted via a simple flow model proposed by Denton and Xu in 1989 were observed for organic vapor flows. Still, roughness affected the downstream loss behavior significantly due to shockwave boundary-layer interactions and flow separation. The new experimental results obtained for this organic vapor are compared with correlations from the literature and available loss data. Full article

Background/Objectives: The overuse and misuse of antibiotics has contributed significatively to the growing problem of the emergence and spread of antibiotic resistance genes among bacteria, posing a serious global challenge to the treatment of bacterial infectious diseases. For these reasons, there is a current and growing interest in the development of effective alternative or complementary strategies to antibiotic therapy for the prevention of fish diseases, which are mainly based on the use of probiotics—in particular, those belonging to the Lactic Acid Bacteria (LAB) group. In this context, the aim of the present study was to characterise, evaluate the genetic diversity and assess the safety of candidate probiotic LAB strains for aquaculture isolated from faeces and intestines of European hakes (Merluccius merluccius, L.) caught in the Northeast Atlantic Ocean (Ireland). Methods: The direct antimicrobial activity of the LAB isolates was tested by the Stab-On-Agar method against key ichthyopathogens. Subsequently, their taxonomic classification and genetic diversity were determined by 16SrDNA sequencing and Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR), respectively. To ensure the in vitro safety of the LAB isolates, their biofilm-forming ability was assessed by a microtiter plate assay; their sensitivity to major antibiotics used in aquaculture, human and veterinary medicine by a broth microdilution method and their haemolytic and gelatinase activity by microbiological assays. Results: All LAB isolates were biofilm producers and susceptible to chloramphenicol, oxytetracycline, flumequine and amoxicillin. A total of 30 isolates (85.7%) were resistant to at least one of the tested antibiotics. None of the 35 LAB isolates showed haemolytic or proteolytic activity. Conclusions: Among the isolated strains, five LAB strains exhibiting the highest antimicrobial activity against aquaculture-relevant ichthyopathogens, taxonomically identified as Streptococcus salivarius, Enterococcus avium and Latilactobacillus sakei, were selected for further characterisation as potential probiotic candidates to promote sustainable aquaculture. To our knowledge, this is the first study to report that hake intestines and faeces represent viable ecological niches for the isolation of LAB strains with antimicrobial activity. Full article

Technological advances continually reduce the effort to digitally transform health-related activities such as rehabilitation and training. Exemplary systems use tracking and vital sign monitoring to assess physical condition and training progress. This paper presents a system for body stability training and coordination evaluation, using cost-efficient tracking and monitoring solutions. It implements the use case of app-guided back posture tracking on the ICAROS Pro training device via SteamVR Tracking 2.0, with pulse and respiration rate monitoring via Zephyr BioHarness 3.0. A longitudinal study on training effects with 20 subjects was conducted, involving a representative procedure created with a sports manager. Posture errors served as the main progress indicator, and pulse and respiration rates as co-indicators. Outcomes suggest the system’s capabilities to foster comprehension of effects and steering of exercises. Further, a secondary study presents a self-developed VR-based exergame demo for future system expansion. The Empatica EmbracePlus smartwatch was used as an alternative for vital sign acquisition. The user experiences of five subjects gathered via a survey highlight its motivating and entertaining character. For both the main and secondary studies, a thorough discussion elaborates on potentials and current limitations. The developed training system can serve as template and be adjusted for further use cases, and the exergame’s reception revealed prospective extension directions. Software components are available via GitHub. Full article

In this study, the real-time shelf life of frozen fillets of two different types of fish, tuna (Thunnus albacares) and hake (Merluccius hubbsi), was studied, simulating a bulk system sale. A glaze treatment was used on all the samples at the beginning, and during the 60-day storage period, the glaze was reapplied at regular intervals on half of the samples (“glazed”), while the other half was not re-glazed (“control”). To assess the quality changes in the two products, the peroxide value (PV), total volatile basic nitrogen (TVB-N), biogenic amines and volatile composition were determined every twenty days. Our results showed that both the glazed and control products did not exceed the legal limits of 35 mg/100 g of TVB-N and 100 mg/kg of histamine. In the hake fillets, in particular, glazing reduced the alteration phenomena associated with oxidative processes. In contrast, because of the high initial thickness of the glazing layer (20% of the weight of the frozen product), the reapplication of glazing during the storage period did not lead to any significant differences between the glazed and control tuna fillets. In conclusion, the different fishes’ compositions affect their conservation after the freezing process, which was improved by means of glazing in the case of the hake fillets. Full article