Small Amounts Research Articles

Coumarin-Modified Starch Fluorescent Nanoparticles as Sensor of Fe3+ and Zn2+ ions Utilizing Dynamic Quenching and Chelation Mechanisms.

Zinc and iron are two essential trace minerals that play a pivotal role in maintaining optimal health and well-being in the human body. Despite being required in relatively small quantities, their significance can be understated as they participate in a wide array of critical physiological processes such as oxygen transport, DNA synthesis, controlling nutrient availability, etc. Understanding the distribution and behavior of these ions in natural water bodies is essential for assessing water quality, studying ecological processes, and managing environmental impacts. In this study, we have developed a dual fluorescence probe using starch which was functionalized with coumarin derivatives, for efficient detection of Fe3+ and Zn2+ ions. This structure led a self-assembled starch/coumarin (SC) fluorescent nanoparticles with strong fluorescence intensity under ultraviolet light (365nm). The quenching effect of Fe3+ on the SC fluorescent probe enabled efficient specific detection of Fe3+. Furthermore, Zn2+ ions increased fluorescence intensity of coumarin compounds (λemission = 459). This phenomenon occurs when the coumarin compound forms a complex or interacts with the zinc ion, resulting in enhanced fluorescence emission. In summary, the developed fluorescent probe offered a promising approach for sensitive and specific detection of iron and zinc ions in aqueous solutions.

Improved Sequentially Processed Cu(In,Ga)(S,Se)2 by Ag Alloying

Alloying small quantities of silver into Cu(In,Ga)Se2 is shown to improve the efficiency for wide and low bandgap solar cells. Low bandgap industrial Cu(In,Ga)(S,Se)2 absorbers are studied, substituting less than 10% of the copper with silver, using absolute photoluminescence and cathodoluminescence spectroscopy. Silver improves the grain size and promotes the interdiffusion of Ga and In across the depth of the absorber, resulting in a smoother bandgap gradient. However, a certain lateral inhomogeneity is observed near the front and back sides. The nonradiative losses in the bare absorbers are reduced by up to 30 meV.

Nagynyomású hidrogénatmoszférás kemence gyártása szénacélok elridegedésének vizsgálatához

Összefoglalás. A hidrogén tárolása iránti igény egyre növekszik, melynek oka az, hogy a hidrogén mint alternatív energiahordozó jelentős szerepet játszik a szén-dioxidkibocsátás-csökkentési törekvésekben. Azonban, az elridegedési folyamatok körében a hidrogén által előidézett károsodások jelentik a legkomolyabb problémát az acélokra nézve. Kutatómunkánk során egy nagynyomású hidrogénatmoszférás hőkezelésre alkalmas autoklávot terveztünk, majd gyártottunk. Az autoklávban P355 NH minőségű alapanyagból kimunkált szabványos Charpy-féle ütőpróbatesteket hőkezeltünk 150 °C-on, 40 bar túlnyomáson, 200 órán keresztül, tiszta hidrogén atmoszférában. A vizsgálatok eredményei alapján megállapítottuk, hogy a jelentős mértékű elridegedés a hidrogénezési folyamat után sem történt. Summary. The demand for hydrogen storage is growing. The primary reason for this is that hydrogen as an alternative energy carrier is playing a significant role in carbon reduction efforts as a fuel for road and maritime transport. In addition, hydrogen can be seen as a long-term flexible energy storage option. Hydrogen as an energy carrier is expected to play a significant role in residential and industrial use in the future. A first step in this development is the mixing of hydrogen with natural gas in small quantities. Increasing the share of hydrogen would not only reduce CO2 emissions, but would also facilitate the development of different hydrogen production methods and thus reduce production costs. The upper safety limit for hydrogen blending with natural gas is set by the national specification of the natural gas supply, possible material quality restrictions and the tolerance of the most sensitive equipment in the network. For this reason, the maximum allowable hydrogen content in natural gas is generally limited to 2,5%. However, among the embrittlement processes, hydrogen-induced damage is the most serious problem for both non-alloy and low-alloy steels. Atomic hydrogen diffuses in steel at high rates. The diffusion rate is orders of magnitude higher than that of other elements; this is due to the small atomic diameter of hydrogen. To investigate the degradation of different carbon steels in a high-pressure hydrogen atmosphere, a hydrogenation furnace was designed and fabricated at the Department of Materials Science and Engineering at BME. The hydrogenation furnace is the main part of a complex mechanical engineering system, for the operation of which the mechanical, heating, electrical supply, control and gas handling components are indispensable. The entire design process of the furnace was led by József Blücher, Professor Emeritus at BME, with the help of the engineers and technicians working on the project. Standard Charpy impact test specimens were machined from P355 NH grade material to test the embrittlement of carbon steels. The hydrogenation temperature was 150 °C, the internal overpressure in the chamber was 40 bar, the hydrogenation time was 200 hours and the atmosphere was hydrogen gas of purity 5.0. The impact test was carried out at -20, 0 and +20 °C. Based on the results of the tests, it can be concluded that there was no significant degree of degradation both before hydrogenation and after prolonged exposure to hydrogen. It can be concluded that the tube material used as a sample is suitable for operation in a hydrogen medium. Based on the analysis of the burst areas and impact values of the impact test specimens, it was concluded that hydrogen did not cause any observable damage to the test material.

Crude credit: The political economy of natural resource booms and sovereign debt management

Oil, gas, and minerals have notoriously adverse effects on institutional quality. But when global liquidity is high, risk-tolerant investors are more willing to lend to all borrowers, even resource-rich countries with low-quality institutions. Despite the availability of cheaper credit during commodity booms, we argue that countries do not increase current borrowing to mitigate future revenue shortfalls during commodity busts. Instead, they rely on resource windfalls to meet their current financing needs, fearing they would otherwise forfeit national policy discretion to global financial markets. We leverage primary evidence from extensive field research across five Latin American countries to show that national economic officials (i.e. finance ministers and central bank governors) are wary of high indebtedness, after past commodity booms ended in cycles of lofty spending, borrowing, and default. For sovereign borrowers, high bond market indebtedness often reduces government discretion over economic policy, whereas windfalls increase it; all else equal, governments will favor the latter. Using data on 22 Latin American and Caribbean countries from 1996 to 2020, we find that governments issue bonds less frequently, in smaller amounts, as their oil and gas production or GDP share from resource rents increases. These findings make an important contribution to our understanding of how commodity cycles affect global capital markets: sovereign borrowers do not fully leverage commodity booms to expand their fiscal space to finance more spending over time.

Catalyst or Obstacle? Green innovation and total factor energy efficiency

Catalyst or Obstacle? Green innovation and total factor energy efficiency

Enhancement of work place comfort through the use of soft landscape

The work environment has been shown to have a great influence on employees’ physical and mental state, as such employers try as much as possible to provide a comfortable working environment. However, recent studies have shown that the work environment is no longer as comfortable as it used to be due to heat gain from the increasing use of hard landscape features and neglect of soft landscape features in the work environment. This has resulted in stress causing both mild and severe health conditions for employees. Thus, this study aims to analyze the use of soft landscape in enhancing users' comfort with the view of reducing stress and health-related issues in the work environment. The paper adopted a mixed method using observation checklists, structured interviews, questionnaires, and case studies. A total of eighteen office complexes were selected to describe the existing situation as related to most office complexes and to also gain insight into the subject matter as already applied to life situations. Structured interviews and questionnaires were also conducted with occupants of the buildings and professionals to hear their perceptions and expectations of their work environment. Results showed that 20 percent of the offices give proper consideration to the use of soft landscapes in the work environment, and 40 percent give inconsiderable attention to soft landscapes while making use of them in small quantities solely for improving the aesthetical value of the building. In comparison, the remaining 40 percent do not consider landscape use as a means of improving comfort in the work environment. Findings also revealed that 80 percent of office buildings give major consideration to parking space using hard landscapes without a proper blend of soft landscapes after building design which hurts occupant comfort. The research concluded that the incorporation of soft landscape elements both within the building using recesses and protrusions and on the building walls through the use of exoskeleton and climbers while incorporating trees, shrubs, flowers, hedges and water around the building can have these required effects on employee’s comfort.

Taurine-mediated gene transcription and cell membrane permeability reinforced co-production of bioethanol and Monascus azaphilone pigments for a newly isolated Monascus purpureus

BackgroundTaurine, a semi-essential micronutrient, could be utilized as a sulfur source for some bacteria; however, little is known about its effect on the accumulation of fermentation products. Here, it investigated the effect of taurine on co-production of bioethanol and Monascus azaphilone pigments (MonAzPs) for a fungus.ResultsA newly isolated fungus of 98.92% identity with Monascus purpureus co-produced 23.43 g/L bioethanol and 66.12, 78.01 and 62.37 U/mL red, yellow and orange MonAzPs for 3 d in synthetic medium (SM). Taurine enhanced bioethanol titer, ethanol productivity and ethanol yield at the maximum by 1.56, 1.58 and 1.60 times than those of the control in corn stover hydrolysates (CSH), and red, yellow and orange MonAzPs were raised by 1.24, 1.26 and 1.29 times, respectively. Taurine was consumed extremely small quantities for M. purpureus and its promotional effect was not universal for the other two biorefinery fermenting strains. Taurine intensified the gene transcription of glycolysis (glucokinase, phosphoglycerate mutase, enolase and alcohol dehydrogenase) and MonAzPs biosynthesis (serine hydrolases, C-11-ketoreductase, FAD-dependent monooxygenase, 4-O-acyltransferase, deacetylase, NAD(P)H-dependent oxidoredutase, FAD-dependent oxidoredutase, enoyl reductase and fatty acid synthase) through de novo RNA-Seq assays. Furthermore, taurine improved cell membrane permeability through changing cell membrane structure by microscopic imaging assays.ConclusionsTaurine reinforced co-production of bioethanol and MonAzPs by increasing gene transcription level and cell membrane permeability for M. purpureus. This work would offer an innovative, efficient and taurine-based co-production system for mass accumulation of the value-added biofuels and biochemicals from lignocellulosic biomass.

Effects of d-allose on anti-brain edema effects and reduction of tumor necrosis factor-alpha and interleukin-6 in the water intoxication model

BackgroundRare sugars, which exist only in very small quantities in nature, have recently attracted attention for their various biological functions in medicine. Among them, d-allose is known to have cytoprotective effects by antioxidant effects. In this study, we investigated whether the antioxidant effects of d-allose reduce brain edema in a water intoxication model of cytotoxic brain edema. Methods: Mice were injected intraperitoneally with distilled water (10 % of body weight) to create a model of brain edema. d-allose was administered orally at 400 mg/kg 30 min before the model was created. Two hours later, the degree of brain edema was measured by the dry-weight method to determine whether d-allose reduced brain edema. As an index of antioxidant effects, we measured changes over time in inflammatory cytokines (tumor necrosis factor-alpha, interleukin-6) induced by the water intoxication model, and whether d-allose reduced inflammatory cytokines 4 h after model creation. Results: Administration of d-allose significantly suppressed brain edema formation of the water-intoxication model. And it significantly reduced inflammatory cytokines (tumor necrosis factor-alpha, interleukin-6). These results suggest that the antioxidant effect of d-allose exerts an anti-inflammatory effect and reduces brain edema.

Effect of cardiolipin on the lamellarity and elongation of liposomes hydrated in PBS

Lamellarity and shape are important factors in the formation of vesicles and determine their role in biological systems and pharmaceutical applications. Cardiolipin (CL) is a major lipid in many biological membranes and exerts a great influence on their structural organization due to its particular structure and physico-chemical properties. Here, we used small-angle X-ray and neutron scattering to study the effects of CL with different acyl chain lengths and saturations (CL14:0, CL18:1, CL18:2) on vesicle morphology and lamellarity in membrane models containing mixtures of phosphatidylcholine and phosphatidylethanolamine with different acyl chain lengths and saturations (C14:0 and C 18:1). Measurements were performed in the presence of Phosphate Buffer Saline (PBS), at 37°C, to better reflect physiological conditions, which resulted in strong effects on vesicle morphology, depending on the type and amount of CL used. The presence of small quantities of CL (from 2.5%) reduced inter-membrane correlations and increased perturbation of the membrane, an effect which is enhanced in the presence of matched shorter saturated acyl chains, and mainly unilamellar vesicles (ULV) are formed. In extruded vesicles, employed for SANS experiments, flattened vesicles are observed partly due to the hypertonic effect of PBS, but also influenced by the type of CL added.Our experimental data from SAXS and SANS revealed a strong dependence on CL content in shaping the membrane microstructure, with an apparent optimum in the PC:CL mixture in terms of promoting reduced correlations, preferred curvature and elongation. However, the use of PBS caused distinct differences from previously published studies in water in terms of vesicle shape, and highlights the need to investigate vesicle formation under physiological conditions in order to be able to draw conclusions about membrane formation in biological systems.

Precise Alkali Supply during and after Growth for High‐Performance Low Bandgap (Ag,Cu)InSe2 Solar Cells

Alkali treatments are crucial for low bandgap (Ag,Cu)InSe2 (ACIS) and Cu(In,Ga)Se2‐based solar cell performance. Traditionally, Ag‐alloying of CIS (ACIS) is grown on soda‐lime glass (SLG) at temperatures exceeding 500 °C, resulting in uncontrolled alkali diffusion from the substrate and variable photovoltaic properties. A substrate‐independent low‐bandgap ACIS growth process is introduced and the impact of controlled supplies of NaF and RbF alkali fluorides before and after absorber growth through precursor layers and post‐deposition treatments (PDT) are investigated. NaF and RbF precursor layers enhance carrier lifetimes and doping density, outperforming the previous SLG‐dependent strategy. Even small quantities of RbF significantly enhance device performance, while specific NaF amount during deposition are necessary to limit grain growth and achieve high doping densities and lifetimes. A certain density of grain boundaries appears crucial for high doping levels. Although subsequent NaF post‐deposition treatment (PDT) does not provide additional benefits with sufficient Na during growth, RbF‐PDT remains crucial. The best performance is achieved with a combination of NaF and RbF precursor layers along with RbF‐PDT, resulting in over 19% efficiency, 605 mV open‐circuit voltage (VOC), 73% fill factor (FF), a carrier density of 3 × 1016 cm−3, and a 700 ns lifetime. This approach supports high‐efficiency ACIS solar cell advancement, particularly for thin‐film tandem photovoltaic devices.

Construction of an organic iron phosphate/graphite carbon nitride hybrid system for improved fire safety of epoxy resin

Enhancing the fire safety of epoxy resin (EP) is crucial due to its widespread but inherent flammability, necessitating the integration of additive flame retardants (FRs) that are effective in small quantities and exhibit efficient flame retardancy. This study constructed a novel, efficient FR by synthesizing organic iron phosphate (ATMP-Fe) and loading it on graphitic carbon nitride (g-C3N4). The resulting hybrid flame retardant (ATMP-Fe/g-C3N4) was added to EP in minimal amount to bolster its flame retardancy and safety features. Incorporating a mere 3 wt% of ATMP-Fe/g-C3N4 into EP significantly improved its flame retardancy and thermal stability. This was evidenced by an increase in the limiting oxygen index from 25.5% for EP to 30.1%, achieving a V-1 rating in the UL-94 test, and producing a 22.0 wt% char residue. Moreover, there was a substantial reduction in peak heat release rate, total heat release, and total smoke production by 36.3%, 27.5%, and 39.3%, respectively. The reduction in pyrolysis products, along with the formation of a dense and stable char layer facilitated by the synergistic effects of phosphorus and iron elements, significantly improved the fire safety of EP. Additionally, the enhanced hydrophobicity, mechanical properties, and electrical conductivity of the EP/3ATMP-Fe/g-C3N4 composite suggested potential for wider application of EP in various fields.

The Organizational Structure, Conduct, and Outcomes of Coimbatore and Erode District Companies Using Different Sugar Substitutes

According to a study on market performance, producers will still receive a higher percentage of the profit even if they sell on a larger scale than other actors. The price difference for ten kilograms of sugar was calculated to be Rs. 100. Still, a lot of consumers choose to pay more for sugar in retail establishments when they buy it in smaller amounts rather than in bulk.  Even if the price difference for ten kilograms of sugar is only Rs. 90, the producer is making a sizable profit margin, according to a market performance analysis. Simple percentage and averages were worked out to assess the general characteristics such as age and experience of the intermediaries and consumers.  However, in this instance, the producer sells in larger numbers, either through the market or directly to the wholesaler, enabling them to keep a considerable portion of the earnings from their products. A market performance analysis indicates that the producer will share in the profit margin at a higher rate than other chain participants. Because 20 kilograms of palm sugar can be made from 60 liters of palmyrah tree sap, his production expenses will match farmers profit margin.

Water jet vacuum cooling system for improving the quality of multiflora honey from bee (Apis dorsata Fabricus) in Indonesia

Honey has great benefits to humans, both as medicine and food. It contains glucose, fructose and water in addition to small quantities of proteins, minerals, organic acids, and vitamins. Vacuum cooling is a rapid cooling technique based on the principle of evaporation, which lowers the boiling point of water based on the vacuum pressure inside a cooler room. A prototype vacuum-cooling jet water system was used to process the honey. Raw honey obtained from the forests of Riau was used in the present study. This study aimed to determine the effect of jet water vacuum cooling with variations in volume (V/V), capacity (12.5%, 25%, and 50%) on the quality of honey (Apis dorsata Fabricus) to accelerate the cooling process and preserve product quality. The cooling mechanical analysis parameters reviewed included the processing time and the lowest maximum pressure. The parameters of the quality of honey observed included moisture content, viscosity, density and total dissolved solids. As a result, the vacuum cooling process can suppress damage to the quality of honey owing to the heating process. At the cooling time and lowest maximum pressure value, the mechanical aspects of the water jet system vacuum cooling process showed the maximum results. The water contents of 12.5% (V/V), 25% (V/V) and 50% (V/V) filling were 13.69%, 12.89%, and 14.25%, respectively. The viscosities at 12.5% (V/V), 25% (V/V) and 50% (V/V) filling were 2.604 Pa.s, 2.355 Pa.s, and 1.644 Pa.s, respectively. Density with 12.5% (V/V), 25% (V/V) and 50% (V/V) filling were 1.52 g/cm3, 1.53 g/cm3 and 1.50 g/cm3, respectively. Total dissolved solid values of honey with 12.5 % (V/V), 25 % (V/V), and 50 % (V/V) fillings were 78.16%, 78.16% and 77.66%, respectively. Water jet vacuum cooling with a 25% chamber volume capacity accelerates honey with the best total dissolved solids, density and moisture content. Vacuum cooling can be used to improve product quality, shorten handling time, extend product shelf life and improve security. Key words: honey, pressure, vacuum cooling, density, moisture content, viscosity

Effect of functional fillers in solvent‐free polyurethane adhesives: Processing and characterization

AbstractThe present work is focused on the study of polyurethane adhesives in the presence of functional fillers (encapsulated enzymes) intended to make them degradable. This is part of a general strategy aiming to recycle multilayer films for packaging, at their end of life, by means of separating the constituent layers as a result of adhesives degradation. Primarily, it was found that the presence of small quantities of functional filler greatly affects both, the quality of the coating process and the kinetics of the adhesive curing. The former, because of the dependency on particle size distribution, leads to high variations in thickness and mechanical properties of multilayers and, the latter, because of a significant catalytic effect (higher curing rates). Indeed, an assessment of the adhesives' kinetics by rheology showed that the pot‐life and the cross‐over point (G′ = G″) for the enzyme‐containing system were obtained three times faster in comparison to the control formulation. These findings were also confirmed by differential scanning calorimetry measurements. On the other hand, by reducing and homogenizing the filler's particle size using separated sieved material (≤50 μm), improvements in coating control as well as in the quality and final properties of the multilayers were evidenced.Highlights Recycling multilayer plastic films for flexible packaging. Encapsulated enzymes to degrade the polyurethane adhesive in specific conditions. The presence of functional fillers affects the coating process. Process optimization to ensure the coating quality control.

Evaluation of Thermoplastic Starch Contamination in the Mechanical Recycling of High-Density Polyethylene

This research highlights the importance of addressing bioplastic contamination in recycling processes to ensure the quality of recycled material and move towards a more sustainable circular economy. Polyethylene (PE) is a conventional plastic commonly used in packaging for which large amounts of waste are produced; therefore, PE is generally recycled and has an established recycling process. However, the contamination of biodegradable polymers in the PE waste stream could impact recycling. This study, therefore, focuses on polyethylene (PE) that has been polluted with a commercial thermoplastic starch polymer (TPS), as both materials are used to produce plastic films and bags, so cross-contamination is very likely to occur in waste separation. To achieve this, recycled PE was blended with small quantities of the commercial TPS and processed through melt extrusion and injection molding, and it was further characterized. The results indicate that the PE-TPS blend lacks miscibility, evidenced by deteriorated microstructure and mechanical properties. In addition, the presence of the commercial TPS affects the thermal stability, oxidation, and color of the recycled PE.

Calorimetry of amorphous calcium carbonate is correlated with its lithification and durability as synthetic stone—implications for CO2 storage and utilization

The properties of amorphous calcium carbonate (ACC) and its transformations to crystalline polymorphs are frequently studied in aqueous systems and in small quantities. In this study, synthetic calcium carbonate stones are created from bulk ACC and crystalline polymorphs, which were precipitated from gaseous CO2, at a gradient of end pH. Some of the ACCs hardened into stones which are durable against an abrasion and impact test, while some of the ACCs create fragile, friable stones. When ACCs which transform to durable stones and those which transform into fragile stones were subject to calorimetry, significant differences were observed. These stones, synthesized from gaseous CO2, can be used as a storage reservoir for utilized CO2 in construction and other infrastructure applications.

Remote Activation of H-H Bonds by Platinum in Dilute Alloy Catalysts.

With heterogeneous catalysts, chemical promotion takes place at their surfaces. Even in the case of single-atom alloys, where small quantities of a reactive metal are dispersed within the main host, it is assumed that both elements are exposed and available to bond with the reactants. Here, we show, on the basis of in situ X-ray absorption spectroscopy data, that in alloy catalysts made from Pt highly diluted in Cu the Pt atoms are located at the inner interface between the metal nanoparticles and the silica support instead. Kinetic experiments indicated that these catalysts still display better selectivity for the hydrogenation of unsaturated aldehydes to unsaturated alcohols than the pure metals. Density functional theory calculations corroborated the stability of Pt at the metal-support interface and explained the catalytic performance as being due to a remote lowering of the activation barrier for the dissociation of H2 at Cu sites by the internal Pt atoms.

Fluorescent Labeling of a Target Protein with an Alkyl Diazirine Photocrosslinker Bearing a Cinnamate Moiety.

A novel fluorogenic alkyl diazirine photocrosslinker bearing an o-hydroxycinnamate moiety has been developed for identification of the targets of bioactive molecules. The o-hydroxycinnamate moiety can be converted to the corresponding 7-hydroxycoumarin derivative, which should be created on the interacting site within the photocaptured target protein. The label yield and fluorescence intensity have been immensely improved in comparison with our previous aromatic crosslinkers to facilitate target identification in small quantities.

Utilizing Data Mining Techniques to Analysis Changes in Purchase Behavior of Batik’s Customers

Sales transaction data contains rich information potentially used to support company competitiveness. However, interpreting and utilizing transaction data in developing marketing strategies remains a challenge, even for big companies. Therefore, this research aims to develop marketing strategies using data mining techniques. A medium-sized company focusing on producing and selling traditional motif clothes (batik) will be used as a case study. The negative sales trend is the biggest issue currently faced by the company. Hypothetically, this problem is caused by imported products sold at lower prices or changing consumer behavior after pandemic covid. Currently, the company only implements simple analysis of its transaction data. The analysis of transaction data, conducted through five data mining stages, yielded a shift from purchasing small quantities to larger quantities, increased purchases during the final week of each month, and increased purchases on religious occasions. Furthermore, the analysis revealed that 31.29% of all transactions were attributed to loyal consumers, and 192 customers exhibited in Cluster 1 (high transaction quantities and high transaction values). Further investigation also revealed that customers categorized as loyal customers and Cluster 1 have different behaviors that can be used to develop further customer relationship programs. Future research can be conducted by employing data mining techniques to study the organization's assortment of products. Management discussions reveal that changes in consumer buying behavior extend to the selection of items and batik themes.

Living in the shore: changes in coastal resource intensification during the Mesolithic in northern Iberia

Recent research on human exploitation of molluscs, echinoderms and crustaceans during the Mesolithic in the Cantabrian region (northern Iberia) has shown significant variability in the intensity of the use of coastal resources by the last hunter-fisher-gatherers throughout the ~ 4000-year expanse of the Mesolithic (10,700 – 6,700 cal BP). Previous studies have proposed hypotheses related to demographic changes to explain intensification events. In this paper we aim to unravel whether climatic and environmental changes, or other social factors, such as demography, were involved in the increase in the use of marine resources at certain times. We employed species representation, quantification and biometric analysis of the shell assemblages from the El Toral III archaeological site (Asturias, northern Iberia) to identify patterns in shell exploitation throughout the stratigraphic sequence. To establish the chronology and distinguish occupation phases of the site, we employed Bayesian modelling of radiocarbon measurements. Faunal results show that marine gastropods such as limpets of the Patella genus and topshells Phorcus lineatus (da Costa, 1778) were the most exploited species, while bivalves, echinoids and crustaceans were present in smaller quantities. The comparison of the results for El Toral III with other Mesolithic sites in the region reveals significant temporal differences in the intensity of collection of marine shell species. Results showed that intensification processes are not clearly related to climate change but to other social factors, such as demography, suggesting that intensification and relaxation in shell collection events were strategies adopted depending on the needs of the human groups at different times.