Search Results (159)

Closed-cell phenolic foam (PF) insulation is widely assumed to exhibit monotonically increasing thermal conductivity after cutting, driven by progressive blowing agent release. This study reports a previously uncharacterized behavior: a consistent decrease–minimum–rebound pattern in the days to weeks after cutting, defined here as the transient thermal conductivity minimum (TTCM). Using n-pentane-blown PF foam, thermal conductivity and mass were tracked under standard (23 °C) and accelerated aging conditions (70 °C, 110 °C; slicing per KS M ISO 11561), complemented by gas chromatography–flame ionization detection (GC-FID), attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FT-IR), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), and scanning electron microscopy (SEM). TTCM reductions of 3.8–16.7% were observed across all closed-cell specimens; a reference PF foam with cell-wall micro-perforations showed no TTCM, establishing intact closed-cell structure as a prerequisite. The mechanism is attributed to redistribution of dissolved n-pentane from the polymer matrix into the cell gas phase, thermodynamically favored by the proximity of n-pentane’s boiling point (36.07 °C) to the heat flow meter (HFM) hot plate temperature (33 °C). In the post-TTCM phase, thermal conductivity rises progressively as n-pentane is displaced by air; the rate of this rise is strongly dependent on diffusion path length. These results establish two mechanistically distinct aging stages and identify their respective governing factors. Full article

Titanium and titanium alloys have been widely used in clinical implants such as dental implants due to their high strength and corrosion resistance. However, their inherent biological inertness and mismatch with the elastic modulus of human bone tissue restrict bone healing and reconstruction. In this study, pure titanium was first modified by micro-arc oxidation (MAO), and then a biodegradable soybean protein isolate (SPI)/polylactic acid (PLA)–polycaprolactone (PCL) composite coating was prepared by using the spin-coating method. The coating was systematically characterized by scanning electron microscopy (SEM), an energy spectrometer (EDS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and atomic force microscopy (AFM), confirming that the composite coating was successfully prepared. An evaluation of the physical and chemical properties showed that the introduction of SPI significantly improved the hydrophilicity, surface roughness and adhesion to the substrate of the coating, regulated the degradation rate, and reduced the elastic modulus to the range of 10–30 GPa, which matches human bone tissue. At the same time, it enhanced corrosion resistance. In vitro MC3T3-E1 osteoblast experiments showed that the coating containing 50% SPI showed better cell compatibility, adhesion ability and osteogenic inducibility, and all groups had good blood compatibility. The SPI/PLA–PCL composite coating effectively improves the biological activity of the pure titanium surface and provides a feasible strategy for the surface modification of titanium implants and bone defect repair. Full article

Relatively low-cost titanium carbide (TiC) materials and metal matrix composites (MMC) are proposed for waste-to-hydrogen conversion. Two types of steels are used as bases prepared from EN 10088 flat products, namely X2CrTi12 (1.4512, AISI 409) and X5CrNi18-10 (1.4301, AISI 304). TiC is mixed with TRIBALOY^® T-800 alloy in powder form and applied via laser-directed energy deposition (DED-LB) over the substrates. For the powder mixture, Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) are performed. The raw materials are investigated for the processes that occur in them under heating. After the solidification of the molten mixture, grinding and polishing are performed to achieve a thin layer. The studies of the obtained MMC include interface zone assessment, hardness and Young’s modulus distribution, microstructural analysis, and visual defect evaluation. Advanced sensors for acoustic emission (AE) and Electrical Contact Resistance (ECR) provided characterization together with micro-scratch testing. The use of photoluminescence spectroscopy is proposed for the new composite materials. The electron transfer pathway can be studied with time-resolved spectroscopy. Renewable energy production by breaking down waste into hydrogen-rich syngas can be achieved through pyrolysis, followed by steam reforming and purification. The obtained novel materials show promising application solutions with increased durability, corrosion, and wear resistance. Full article

Non-destructive diagnostic approaches play a crucial role in cultural heritage studies by enabling the assessment of artworks’ conservation conditions without causing damage. This work presents the case study of the tempera painting Cristo in Trono, by Domenico Morelli and Paolo Vetri, located in Amalfi (SA, Italy). A multi-analytical approach combining portable and non-invasive techniques was employed. Hygrometric tomography revealed anomalous surface moisture values (up to 23 units) along the edges and wooden joints, identifying areas requiring particular attention during conservation. Infrared reflectography (IR-R) detected preparatory drawings, compositional changes, and evidence of previous restoration interventions. X-ray fluorescence spectroscopy (XRF) identified the elemental composition of the pigments, indicating the use of cinnabar (or vermilion), ultramarine (or lapis lazuli), ochres, lead white (Biacca), and brass (Orone) for the golden background. Multivariate statistical analysis of the XRF data (PCA and HCA) revealed compositional heterogeneity and chemically distinct areas within apparently similar chromatic regions. Micro-invasive analyses complemented these results by providing information on the stratigraphy and material composition. Fourier-transform infrared (FT-IR) spectroscopy identified polyvinyl acetate (PVA), attributed to previous restoration treatments and associated with the yellowing of lead white, together with protein-based binders. Microscopic observations revealed the woven structure of the support, pigment-layer cracking, and degradation features, while the interaction of the brass with atmospheric agents and marine chlorides was found to be responsible for the alteration of the original golden background to a greenish-gold hue. The lower part of the canvas exhibited the most severe deterioration, resulting from higher moisture levels, unsuitable past restoration treatments, and prolonged exposure to humidity, atmospheric pollutants, and marine aerosols, highlighting the importance of integrated diagnostic investigations for planning effective conservation and restoration strategies. Full article

ZIF-8-modified micro-arc oxidation (MAO) coatings have attracted considerable attention for improving the corrosion resistance of aluminum alloys, owing to their combined barrier and chemical protection effects. In this work, ZIF-8/MAO composite coatings were fabricated via in situ solvothermal growth, and the effects of solvothermal temperature and time on coating evolution and corrosion performance were systematically investigated. The coatings were characterized by field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The results show that increasing the solvothermal temperature promotes ZIF-8 formation, which may be related to enhanced coordination reactions and particle growth. Prolonging the solvothermal time induces a transition from ZnO-dominated coatings at 8 h to ZIF-8-dominated structures at 16–24 h, whereas unconverted ZnO is still detected after prolonged growth. The in situ-grown ZIF-8 particles cover the MAO surface and contribute to the sealing of surface micropores and cracks, forming a more compact composite barrier structure. The reduced coating performance at 220 °C or after 32 h may be associated with excessive particle refinement, local structural imperfections, or reduced coating integrity under prolonged or high-temperature solvothermal conditions. Electrochemical impedance spectroscopy (EIS) results reveal that the composite coating exhibits a charge transfer resistance more than one order of magnitude higher than that of the bare MAO coating, indicating significantly enhanced barrier protection. These findings demonstrate that in situ-grown ZIF-8 is an effective strategy for improving the corrosion resistance of MAO coatings on aluminum alloys. Full article

Micro- and nanoplastics (MNPs) are emerging environmental contaminants of increasing relevance to human health. Growing evidence suggests that, following ingestion, inhalation, or, less convincingly, dermal exposure, MNPs may cross biological barriers, enter lymphatic and vascular compartments, and reach the liver. Owing to portal blood flow, sinusoidal architecture and Kupffer cell activity, the liver appears to be one of the principal sites of early particle sequestration. Human biomonitoring, ex vivo and postmortem studies have detected MNPs in blood and multiple organs, including the liver, although the currently available evidence remains limited and methodologically heterogeneous. Their identification relies on multistep analytical procedures that integrate sample pretreatment with FTIR, Raman spectroscopy, LD-IR, Py-GC-MS and supplementary imaging methods. However, each of these techniques presents significant limitations, particularly in the analysis of nanoplastics. Experimental studies indicate that MNPs may induce hepatic injury through oxidative stress, mitochondrial impairment, endoplasmic reticulum stress, inflammation, DNA damage, dysregulated lipid metabolism and disruption of the gut–liver axis, consequently contributing to steatosis, cholestatic anomalies and fibrosis. Consequently, MNPs should be considered potential contributors to liver pathology, although more comprehensive human data are still required. Full article

The study presents an approach to the synthesis of micro- and nano-sized biosilica from rice husk ash (RHA) and describes its effective incorporation into cementitious composites for 3D concrete printing (3DCP). It is demonstrated that the calcination of rice husk at 700 °C, followed by sonochemical treatment, leads to the formation of a nanoscale silica phase with high pozzolanic reactivity. X-ray powder diffraction (XRD), infrared spectroscopy (IR), differential thermogravimetric analysis (DTG), and scanning electron microscopy (SEM) show that the incorporation of nano-biosilica (NBS) into the cementitious composites accelerates the hydration process through a nucleation effect and pozzolanic reaction. This, in turn, densifies the hardened cement microstructure and improves compressive strength significantly. Laboratory 3D concrete printing tests demonstrate that adding 1.72 wt.% NBS improves shape retention, decreases layer slump, and improves interlayer bond strength. The results indicate the viability of rice husk ash-derived biosilica as a supplementary cementitious material (SCM) in 3DCP due to its positive influence on the concrete mortar properties and parameters. Full article

With the shortage of natural aggregates and the massive accumulation of iron tailings (ITs) solid waste restricting the sustainable development of asphalt pavement engineering, replacing natural aggregates with ITs has become a promising low-carbon solution with prominent economic and social benefits. However, the poor interfacial adhesion between ITs and asphalt severely restricts the engineering application of tailings, and the micro-interaction mechanism at their interface still lacks systematic clarification, which is the key research gap addressed in this work. Different from conventional macro road performance tests, this study innovatively combined molecular dynamics (MD) simulation with microscopic characterization, including Fourier transform infrared spectroscopy (FT-IR) and atomic force microscopy (AFM), to comprehensively reveal the interfacial interaction mechanism between ITs and asphalt at the molecular and microscales. The results indicate that asphalt molecules exhibit higher aggregation concentration and diffusivity on Al₂O₃ and Fe₂O₃ surfaces than on SiO₂ surfaces, proving stronger interfacial interaction between asphalt and iron-rich oxide minerals. Moderate temperature optimizes the adhesion performance of asphalt with Al₂O₃ and Fe₂O₃, while the interfacial bonding of asphalt on CaCO₃ and SiO₂ weakens as temperature rises. The silane coupling agent KH-550 can effectively react with acidic minerals, SiO₂ minerals in ITs, which significantly increases the concentration, diffusion coefficient, and distribution uniformity of asphalt molecules at the interface. FT-IR results verify that the combination of ITs and asphalt mainly relies on physical adsorption without generating new chemical bonds. AFM tests further confirm that alkaline minerals improve the surface roughness of asphalt mastic, and KH-550 greatly enhances the micro-adhesion force of the interface. The novelty of this work lies in clarifying the mechanism of typical mineral components in ITs and revealing the modification enhancement law of silane coupling agent and alkali minerals at the micro level. This study provides a scientific theoretical support for the high-value engineering utilization of ITs in asphalt pavement, and offers a reference for optimizing the interfacial modification design of solid waste aggregate. Full article

Non-obstructive azoospermia (NOA), a severe male infertility condition with impaired or absent sperm production, is treated by microsurgical testicular sperm extraction (micro-TESE), whose success depends on identifying seminiferous tubules with active spermatogenesis. To address this challenge, we demonstrate that mid-infrared photothermal (MIP) microscopy can provide label-free molecular signatures to distinguish different NOA subtypes in patient tissues. We applied MIP microscopy and MIP-guided IR spectroscopy to testicular tissues from obstructive azoospermia (normal spermatogenesis) and idiopathic NOA (abnormal spermatogenesis) patients. Tissue classification was performed using a Singular Value Decomposition–Random Forest (SVD-RF) pipeline. MIP imaging revealed distinct lipid distribution and reduced lipid content in NOA tissues compared to normal spermatogenic tissues. Using SVD to extract spectroscopic features and RF for classification, we achieved 94.03% accuracy in distinguishing testicular tissues as normal spermatogenesis or three pathological subtypes of idiopathic NOA. These findings demonstrate MIP microscopy as an effective tool for characterizing the spermatogenic potential of seminiferous tubules based on their molecular composition, potentially facilitating improved sperm retrieval strategies. Full article

Lunar meteorites provide access to a geographically unconstrained record of the Moon, offering key insights into crustal diversity and interior evolution beyond the Apollo and Luna landing sites. Among them, the feldspathic breccia NWA 11421 is of particular interest because of its complex mineralogy and the presence of a dunite clast interpreted as a fragment of the lunar mantle. We present a non-destructive, multi-scale characterization of NWA 11421 using VIS–IR spectroscopy, µ-FTIR mapping, and µ-EDXRF. Results identify a polymict feldspathic breccia dominated by an anorthite matrix, with significant low-Ca pyroxene and olivine occurring as discrete mafic microdomains at the micro-scale. Near-infrared pyroxene band positions and Christiansen Feature (CF) value further indicate relatively mafic and primitive components. In addition, NWA 11421 CF value match with lunar crater-ejecta regions observed by the Diviner radiometer (LRO). These findings are consistent with a deep crustal or shallow mantle origin for NWA 11421 and may provide useful constraints for the selection of future landing sites, particularly in the context of ISRU-oriented human exploration, where mafic components are key sources of Fe and Mg. Full article

Microplastics spread through the environment in various ways. Inland waters are an ideal medium for their dispersal, as they collect pollutants from various sources and transport them over long distances. From there, microplastics can enter the marine environment, break down into smaller particles or end up in drinking water treatment plants. However, the fate, transport and potential health effects of microplastics after ingestion of drinking water and water in food are not yet fully understood. It is therefore necessary to evaluate the quantification and identification of microplastics in drinking water by analysing real samples in order to assess the potential impact on human health. To this end, microplastic contamination in 32 treated drinking water samples from a surface water treatment plant in north-eastern Italy were analysed using micro-Fourier transform infrared spectroscopy (µ-FT-IR). The results indicated low levels of contamination, with all the samples containing less than 170 microplastics per litre, which is in line with European drinking water levels. Polyolefins with size 50–500 µm, such as polypropylene and polyethylene, were the predominant polymers detected (50.2%), while surprisingly polyethylene terephthalate was scarcely present (0.1%, size range 10–50 µm). Statistical analysis revealed a significant negative correlation between microplastic concentration and sampling volume, with larger volumes yielding fewer particles. This inconsistency likely results from the lack of bottle rinsing when only a fraction of the sampling volume is filtered. It was also found that rinsing the sampling bottles with ethanol alone prior to analysis was sufficient to ensure accurate quantification. These results highlight the challenges in standardising the detection of microplastics in drinking water and underline the need for optimised sampling protocols. Full article

The carved lacquer horse-hoof-shaped box excavated from Yulin, Shaanxi Province, represents a typical example of lacquerware preservation in the arid environment of northern China, exhibiting multiple deterioration phenomena, including substrate deformation, lacquer film peeling, and pigment fading. To systematically analyze its structural composition and craftsmanship features, this study employed multiple analytical techniques, including ultra-depth microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), confocal laser micro-Raman spectroscopy (Raman), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Based on these analyses, a targeted conservation protocol was developed. Results revealed that the carved lacquer horse-hoof-shaped box has a wooden substrate structure, with the lacquer ash layer composed of mixed materials, including calcium carbonate (CaCO₃), quartz (SiO₂), and hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂). The lacquer film layer contains Chinese lacquer and plant oils, with cinnabar applied as surface decoration. Based on these findings, a stratified reinforcement conservation strategy was proposed: under dynamic monitoring with optical fiber sensors and three-dimensional scanning, the wooden substrate was reinforced with moisture-curable polyurethane (MCPU), the lacquer ash layer was strengthened with acrylic emulsion (Primal AC33), aged areas were restored with nano calcium hydroxide (Ca(OH)₂) aqueous dispersion, and polyethylene glycol (PEG 400) poultice application was implemented to restore the flexibility of the lacquer film. This research significantly enhanced the integrity and stability of the carved lacquer horse-hoof-shaped box, providing practical evidence and technical references for the scientific conservation of lacquerware excavated from arid regions of northern China. Full article

This article presents a comprehensive analysis of the polychrome paintings on the Flower Peking Opera Theatre in Bozhou, Anhui Province, China. A multi-technique approach was employed, including polarized light microscopy (PLM), X-ray fluorescence (XRF), micro-Raman spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy with energy-dispersive spectrometry (SEM-EDS), and Herzberg staining to determine the composition and methodologies involved in the formation of the pigment layer, the white primer, and the ground layer. The analysis identified cinnabar (red), both artificial ultramarine and Prussian blue (blue), a mixture of barite and gypsum (white), a mixture of chromite and Prussian blue (green), and carbon black (black) in the pigment layer. The ground layer was found to consist of clay and plant fibers (cotton and hemp), while the white prime layer was primarily composed of barite and gypsum. This research provides insights for future conservation and restoration efforts. Full article

P-cresol, indole and indole-3-acetic acid (IAA) are catabolites of amino acids, formed by the gut microbiome. Most of these aromatic hydrocarbon derivatives are excreted by the colon before reentering the body to form “exogenous” protein-bound uremic toxins (PBUTs), which aggravate chronic kidney disease (CKD). Removal efficiencies of these PBUT precursors from model phosphate-buffered saline solutions by three different surface-modified nanoporous carbon adsorbents (PCs) were studied. PCs were produced by physicochemical and/or acid base activation of carbonized rice husk waste. Removal rates achieved values of 32–96% within a 3 h contact time. High micro/mesoporosity and surface chemistry of the N- and P-doped biochars were established by N₂ adsorption studies, SEM/EDS analysis, XPS and FT-IR-spectroscopy. The ammoxidized PC-N1 had the highest adsorption capacity (1.97 mmol/g for IAA, 2.43 mmol/g for p-cresol and 2.42 mmol/g for indole), followed by “urea-nitrified” PC-N2, whilst the phosphorylated PC-P demonstrated the lowest adsorption capacity for these solutes. These results do not correlate with the total pore volume values for PC-N2 (0.91 cm³/g) < PC-P (1.56 cm³/g) < PC-N1 (1.84 cm³/g), suggesting that other parameters such as the micropore volume (PC-N1 > PC-N2 > PC-P) and the interaction of surface chemical functional groups with the solutes play key roles in the adsorption mechanism. N-doped PC-N1 and PC-N2 have basic functional groups with higher affinity with acidic IAA and p-cresol. The ion-exchange mechanism of phenolic and indolic compound chemisorption by nanoporous carbon adsorbents, modified with surface N- and P-containing functional groups, has been proposed. Full article

Understanding the molecular mechanisms of protein–nanoparticle interactions is crucial for enabling the development of new applications in biomedicine and nanotechnology. Ubiquitin, an important and structurally small functional protein, plays a central role in numerous cellular processes. Therefore, in the current study, we focused on the few-layer graphene (FLG)–Ubiquitin complexes formed by exfoliating FLG structures using only water. Optical spectroscopic techniques (Raman, FT-IR, UV-Vis and circular dichroism) were employed to investigate these complexes on the molecular level. Overall, both CD and FT-IR data reveal that the formation of the FLG–Ubiquitin complexes occurred without inducing disordered structures in the protein. Based on the existence of a blue shift (hypsochromic shift) in the UV-Vis data, the presence of a single tyrosine and two phenylalanine residues in ubiquitin enables the detection of FLG-induced micro-environmental changes, particularly influencing the protein’s β-sheet and α-helix structures. The CD spectral results and CDPro quantitative estimations are in line with ATR FT-IR results, confirming the absence of disordered structure formation while altering the protein’s chirality. UV-Vis and CD spectroscopy results revealed concentration-dependent trends consistent with FLG–protein interactions that preserve the overall protein structure. This study has potential applications in both academic research and practical usage, particularly in biomedicine and nanotechnology specifically for FLG. Full article