Search Results (11)

This study explores a disulfide-selective cross-linking strategy for natural rubber (NR) to formulate elastomeric materials with engineering-relevant mechanical properties. A disulfide-containing bismaleimide (BIS) cross-linker was synthesized from cystamine and maleic anhydride and compounded with NR. Three formulations were prepared: control (no inhibitor), CuCl₂-based, and copper(II) methacrylate (CuMA) based compounds, with BIS concentrations ranging from 3.55 to 8.88 phr. Rheological and mechanical testing revealed that CuCl₂ formulations suffered from molecular degradation, poor thermal stability, and mechanical brittleness due to oxidative reactions in the absence of antioxidants. In contrast, CuMA-based compounds exhibited intermediate molecular weights prior to curing, stable thermal behavior, and improved mechanical properties, including enhanced torque and tensile strength, indicating effective cross-linking and partial recyclability. The control formulations also performed reasonably well but did not match the mechanical strength of conventional sulfur-vulcanized NR. The results demonstrate that metal coordination, particularly with CuMA, can modulate disulfide metathesis kinetics and offer a pathway to thermally triggered network rearrangement. Overall, CuMA emerges as a promising candidate for developing high-performance, recyclable rubber materials, while CuCl₂ requires further stabilization strategies. This work establishes a baseline for future recyclability studies and advances the design of dynamic covalent networks in elastomers. Full article

Introduction: Disease knowledge and health literacy are important health competencies that individuals with chronic conditions like Sickle Cell Disease (SCD) need for self-management. This study aimed to: (I) describe and compare SCD knowledge and health literacy levels in adolescents and young adults (AYAs) with SCD in Benin; (II) examine associations between genotype, socio-demographic factors, health literacy, and SCD knowledge; and (III) examine the associations between patients SCD knowledge, health literacy, socio-demographic factors, and (a) frequency of hospitalisations and (b) frequency of occurrence of painful episodes. Methods: AYAs aged 14 to 25 years with SCD attending routine consultations at two Benin clinics—the National Sickle Cell Disease Centre (CPMI-NFED) and the Haematology clinic of the University Teaching Hospital (CUMAS), completed a questionnaire assessing SCD knowledge and health literacy (Health Literacy Measure for Adolescents, HELMA). Results: Most participants had inadequate health literacy: 72.1% at CPMI-NFED and 82.1% at CUMAS, with no significant differences between centres (t = 1.642, p = 0.200). CPMI-NFED participants had higher SCD knowledge than those at CUMAS (t = 4.303, p = 0.038). Higher SCD knowledge (β = 0.466; p < 0.001) and health literacy (β = 5.081; p < 0.001) were associated with older age. Tertiary-level education was associated with higher health literacy (β = 4.286; p = 0.023). Participants with high SCD knowledge experienced fewer painful episodes (IRR = 0.777, p = 0.046), but no significant differences in hospital admissions (IRR = 0.764, p = 0.162). Conclusions: Inadequate health literacy is common in AYAs with SCD in Benin. Having high SCD knowledge may have an impact on the occurrence of painful episodes. Full article

This study applies surveying and representation techniques to analyze the cavities of the Cumae site, an archeological park located in the Phlegraean Fields in the Campania region, providing a documentary basis for monitoring, maintenance, and enhancement efforts. The process core is the comparative management of the numerical models produced employing technologies such as laser scanning, photogrammetry, and structured light scanning, supported by a georeferenced topographical network. The 3D models produced are used for the extraction of ortho-planes and bidimensional drawings of the various cavities from which to initiate the procedures for redesigning and analyzing the entire artifact. Specific research carried out on the Antro della Sibilla enabled a detailed 3D description of the tuff-carved surfaces, helping the interpretation of the manufacture in the optic of consolidation and musealization interventions. The interdisciplinary approach employed, in which historical–archeological, geological–structural, and diagnostic sciences contributed correlatedly, ensures a comprehensive program of data representation. Full article

The food industry generates considerable byproducts that are often discarded and have high contents of usable bioactive compounds. The aim of this study was to characterize the byproducts of camu-camu (Myrciaria dubia) (shell and seed) and guava (Psidium guajava) (shell) production. The extraction and stabilization of the bioactive compounds of camu-camu and guava were also optimized. The variables of ultrasound-assisted extraction (UAE) (shaking time, sonication time and volume–mass ratio) and mechanical shaking-based extraction (MS) (shaking speed, volume–mass ratio and shaking time) were optimized with the surface response method and a Box–Behnken design. The responses studied were total phenolic content (TPC) and antioxidant capacity (AC) evaluated by the degradation of the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) technique and by the ferric reducing antioxidant powder (FRAP) test. For ultrasound-assisted extraction, the optimal sonication time was 15 min for both the M. dubia and P. guajava shells, and the volume–mass ratios were 50 mL/g for the M. dubia shell and 60 mL/g for the P. guajava shell. However, for M. dubia seeds, there was an agitation time of 3 h, a sonication time of 4.4 min and a volume–mass ratio of 50 mL/g. During extraction by mechanical stirring, the optimal volume–mass ratio for both M. dubia seeds and P. guajava shells was 60 mL/g, while for M. dubia shells, it was 50 mL/g. For the shells and seeds of M. dubia and the shells of P. guajava, the optimal stirring times were 2, 6.4 and 7.7 h, respectively, and the optimal stirring speeds were 172.2, 250 and 256.3 rpm, respectively. Under these optimal conditions, the highest total phenolic content (TPC) results were acquired from the cuma-cuma peel (CCP) extract (26.2 mg gallic acid equivalent (GAE)/g sample) obtained by UAE and from guava peel (GP) extract (27.9 mg GAE/g sample) obtained by MS. The optimized models showed that MS was more efficient than UAE for obtaining bioactive compounds from byproducts of M. dubia and P. guajava. However, UAE required much shorter extraction times than MS. In conclusion, the models obtained for the recovery of bioactive compounds could be applied in large-scale industries to fully exploit the byproducts studied. Full article

In this paper, carbon-matrix-supported copper (Cu) and cobaltous oxide (CoO) nanoparticles were obtained by using coordination polymers (CPs) as a precursor. The aqueous solutions of copper methacrylate (CuMA) and cobalt methacrylate (CoMA) were preferentially prepared, which were then mixed with anhydrous ethanol to fabricate dual metal ion coordination polymers (CuMA/CoMA). After calcination under an argon atmosphere, the Cu-CoO/C nanocomposite was obtained. Scanning electron microscope (SEM) and transmission electron microscope (TEM) showed that the material has banded morphology, and the dual functional nanoparticles were highly dispersed in the carbon matrix. The prepared material was used in a heterogeneous Fenton-like reaction, with the aim of replacing traditional ferric catalysts to solve pH constraints and the mass production of ferric slime. The obtained nanocomposite showed excellent catalytic performance on the degradation of methylene blue (MB) at near-neutral conditions; the discoloration efficiency is about 98.5% within 50 min in the presence of 0.15 mmol/mL H₂O₂ and 0.5 mg/mL catalyst. And good reusability was verified via eight cycles. The plausible pathway for MB discoloration and the possible catalytic mechanism was also proposed. Full article

The paper presents the first archaeometric results on a selection of ancient Roman coins (antoniniani) from a treasure found in the Roman necropolis area of ancient Cumae (Southern Italy) during archaeological campaigns by the Centre Jean Bérard. A multi-analytical approach consisting of non-destructive techniques (stereomicroscopy, FESEM-EDS, pXRF, Raman, μ-CT) was implemented on the better-preserved coins of the treasure in order to investigate the chemical composition of the alloy. Chemical analysis showed that the Roman mint prepared the metal with an argentiferous lead–bronze alloy. A group of coins presents a low content of the precious metal, which is in agreement with the financial crisis of the Roman Empire of the third century. Another group of two coins shows a higher silver content, which is in agreement with their issue or with the Mediolanum mint standards. In addition, the external layers of corroded coins were analysed to explore the state of conservation of the patina and to identify the corrosion products. Some typical corrosion patinas due to post-depositional conditions were identified. The mineralogical characterisation of the corrosion products enables us to implement adequate conservation strategies, and the presence of more aggressive patinas suggests immediate interventions. Full article

The paper’s argument is that the specific characteristics of cultural heritage goods help minimise insensitivity to the scope, also known as the embedding effect, of contingent valuation (CV) estimates. This bias happens when estimates of willingness to pay (WTP) do not increase with the quantity of the goods presented, as expected from economic theory. The presence of such effect has been actively debated in the literature since it raises major concerns about the validity of the method itself and its uses within a social cost benefit analysis framework. The research presented in this paper discusses one of the few methodological studies testing the embedding effect within and across samples for cultural heritage goods. The research uses empirical data gathered from three independent and comparable samples focusing on the archaeological park of Campi Flegrei in Italy and two of its components: the Castle of Baia and the archaeological park of Cuma. Findings successfully prove that CV estimates relate to the quantity being valued and could be used with confidence by policy makers concerned with an inclusive, sustainable approach to cultural capital management. Full article

The Bay of Naples, Italy, is renowned for its archaeological heritage. However, this heritage is threatened by the combination of weathering and the biological activity of microorganisms. Fungi are among the major agents of microbial deterioration of cultural heritage since they can cause cracks and lesions in monuments due to the penetrating force of their hyphae. Such biodeterioration may weaken the stone structures and threaten the longevity of these culturally important monuments. To address this, we collected, identified, and maintained in culture filamentous fungi that colonize the external surface of monuments at five important archaeological sites near Naples, namely Cuma, Ercolano, Nola, Oplonti, and Pompei. We isolated a total of 27 fungal taxa, all of which can be cultivated in the laboratory, and form a part of our reference collection. Many of the described fungal taxa we found belong to groups that are involved in stone biodeterioration and can thus be considered as model organisms for in vitro studies. These results emphasize the importance of identifying and cultivating fungal stock cultures for non-invasive studies on biodeterioration. Our newly developed reference collection represents a useful resource that is available to other researchers to rapidly identify potentially hazardous fungi on other monuments. Full article

Pancratium maritimum (Amaryllidaceae) is a bulbous geophyte growing on coastal sands. In this study, we investigated changes in concentrations of metabolites in the root and leaf tissue of P. maritimum in response to mild salt stress. Changes in concentrations of osmolytes, glutathione, sodium, mineral nutrients, enzymes, and other compounds in the leaves and roots were measured at 0, 3, and 10 days during a 10-day exposure to two levels of mild salt stress, 50 mM NaCl or 100 mM NaCl in sandy soil from where the plants were collected in dunes near Cuma, Italy. Sodium accumulated in the roots, and relatively little was translocated to the leaves. At both concentrations of NaCl, higher values of the concentrations of oxidized glutathione disulfide (GSSG), compared to reduced glutathione (GSH), in roots and leaves were associated with salt tolerance. The concentration of proline increased more in the leaves than in the roots, and glycine betaine increased in both roots and leaves. Differences in the accumulation of organic osmolytes and electron donors synthesized in both leaves and roots demonstrate that osmoregulatory and electrical responses occur in these organs of P. maritimum under mild salt stress. Full article

Natural hazards threaten many archaeological sites in the world; therefore, susceptibility analysis is essential to reduce their impacts and support site fruition by visitors. In this paper, rockfall susceptibility analysis of the western slope of the Cumae Mount in the Cumae Archaeological Site (Phlegraean Fields, Naples), already affected by rockfall events, is described as support to a management plan for fruition and site conservation. Being the first Greek settlement in southern Italy, the site has great historical importance and offers unique historical elements such as the Cumaean Sibyl’s Cave. The analysis began with a 3D modeling of the slope through digital terrestrial photogrammetry, which forms a basis for a geomechanical analysis. Digital discontinuity measurements and cluster analysis provide data for kinematic analysis, which pointed out the planar, wedge and toppling failure potential. Subsequently, a propagation-based susceptibility analysis was completed into a GIS environment: it shows that most of the western sector of the site is susceptible to rockfall, including the access course, a segment of the Cumana Railroad and its local station. The work highlights the need for specific mitigation measures to increase visitor safety and the efficacy of filed-based digital reconstruction to support susceptibility analysis in rockfall prone areas. Full article

Archeological sites close to coastal volcanic-sedimentary aquifers are threatened by groundwater contaminated by natural and anthropogenic processes. The paper reports on a hydrogeological, chemical (major, minor and trace elements) and isotopic (δD-H₂O, δ¹⁸O-H₂O, δ¹⁵N-NO₃, δ¹⁸O-NO₃, δ¹¹B, ²²²Rn) survey of groundwater at the Cumae archaeological site, which is located in the coastal north-western sector of the volcanic district of Phlegraean Fields (southern Italy), where groundwater flooding phenomena occur. Results show the presence of a complex coastal volcanic-sedimentary aquifer system where groundwater quality is influenced mainly by: (i) aquifer lithology and localized ascent of magmatic fluids along buried volcano-tectonic discontinuities, (ii) mixing of groundwater, deep mineralized fluids and seawater during groundwater pumping, and (iii) nitrate contamination >50 mg/L from non-point agricultural sources. Moreover, δD and δ¹⁸O point toward fast recharge from seasonal precipitations, while the isotopic ratios of N and O in nitrate reveal the contribution of mineral and organic fertilizers as well as leakage from septic tanks. Results can assist the local archaeological authority for the safeguarding and management of the archaeological heritage of the Cumae site. Full article