Search Results (105)

This article describes the development of a compact and affordable variable-temperature NMR instrument designed primarily to measure dynamic molecular motion in solids and liquids. The instrument consists of Lab-Tools’ Mk4 palm-top time-domain NMR spectrometer fitted with a Peltier-cooled variable-temperature probe inside a shimmed Halbach magnet. Measurement of NMR relaxation times T₁, T₂, and ${\mathrm{T}}_1\rho$ is possible over the temperature range −20 °C to 70 °C with cooling and heating rates, and data acquisition is controlled from an integrated mini-PC. The overall footprint of the instrument is roughly that of a shoe box, making both in-the-field and bench-top measurements possible. Applications of this instrument include measuring pore-size distribution in porous rocks, the viscosity of oils and tars trapped in porous rock, the properties of polymers, and the viscosity of the liquid components of foods (e.g. fruits, vegetables and seeds). Results of test measurements for calibrated oils and olive oil are presented together with measurements of molecular mobility in a solid polymer. Full article

Early-age strength development and carbon emissions represent specific operational constraints in underground cemented tailings backfill (CTB) operations. A pH and ionic pre-conditioning-assisted CO₂ mineralization process was evaluated for carbonate-rich cemented tailings backfill designed to improve early UCS while retaining measurable CO₂ uptake through systematic process control and optimization. Skarn-type tailings (CaO 16.74 wt%, total carbonates 34.7 wt%) were subjected to screening under nominal pH and ionic pre-conditioning treatments (4.0–11.5), CO₂ pressure (0–0.5 MPa), cement-to-tailings ratio (1:3–1:12), and slurry concentration (66–78%). Strength evolution (1–28 d), mineralization products were characterized using TGA as the primary CO₂-uptake method, with XRD used for semi-quantitative phase-trend assessment, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) with selected-area electron diffraction (SAED), X-ray computed tomography (CT), and nuclear magnetic resonance (NMR). Under optimal conditions (pH 8.5, 0.3 MPa CO₂ pressure, 48 h mineralization, 72–74% solids), mineralized specimens achieved 2-day uniaxial compressive strength equivalent to 1.47-times the 3-day control strength (p < 0.01), with peak net CO₂ sequestration of 37.1 g/kg. EBSD analysis of 347 grain boundaries and TEM-SAED examination of multiple foil sections supported the occurrence of syntaxial calcite overgrowth on primary carbonate debris as a major interfacial transition zone strengthening mechanism. Interconnected pore cluster volume decreased by 70.6%; Zn²⁺ and Pb²⁺ leaching decreased by 67.2% and 71.8%, respectively. A shrinking-core kinetics-Ryshkewitch model with pH-dependent correction functions predicted 3-day strength with acceptable accuracy for TW-A and TW-B, whereas TW-C showed a −27.3% deviation, identifying acidic and sulfate-rich wastewater as a boundary condition outside the reliable model domain. Field coring at −500 m depth provided pilot-scale evidence that a 23 mm mineralized shell was consistent with localized reduction of shallow exposed-face instability risk during the early free-standing period. Overall, the pH and ionic pre-conditioning-assisted CO₂ mineralization process is proposed as a laboratory-supported and field-informed screening framework for simultaneous early-strength enhancement and partial carbon sequestration in carbonate-rich cemented tailings systems. The resulting models and parameter guidance should be interpreted as preliminary design tools requiring further factorial optimization and long-term field validation before full site-specific deployment. Full article

The application of low-field time-domain nuclear magnetic resonance (TD-NMR) to measure water content and assess moisture-related relaxation behavior in sludge samples has been investigated. The results of TD-NMR measurements on 26 dewatered sludge samples revealed a strong correlation between sludge water content and key features of the T₂ distribution curves, including the maximum relaxation time and peak area, demonstrating the potential of the TD-NMR method for estimating sludge moisture content. No consistent relationship was observed between the peaks in T₂ relaxation distribution curves obtained by Inverse Laplace Transform (ILT) and the expected water fraction ratios, apparently because the sludge structure is highly variable from sample to sample. Despite the complex and heterogeneous nature of sludge samples, the direct correspondence between key features of the T₂ relaxation curves and moisture content demonstrates the high potential of TD-NMR as a tool for rapid and reliable moisture monitoring, even in an online device configuration. Full article

The central role of YB-1 in messenger ribonucleoprotein particle (mRNP) metabolism and stress-granule biology highlights the importance of defining the determinants of its self-assembly. YB-1 fibrillogenesis has been attributed primarily to the cold shock domain (CSD). Here, we show that the YB-1 fragment spanning residues 1–129 (AP–CSD) form amyloid fibrils under near-physiological ionic strength (0.12–0.15 M KCl). Fibrillization proceeds without a pronounced exponential growth phase and increases approximately linearly over 45–50 h. Far-UV circular dichroism (CD) and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) indicate no substantial change in overall secondary-structure content during aggregation. In parallel, ¹H nuclear magnetic resonance (NMR) spectroscopy reveals the depletion of soluble species, and oriented fiber X-ray diffraction displays the hallmark cross-β reflections at approximately 4.7 Å and 10 Å. The prolonged formation time implies an activation barrier that is unlikely to require global refolding. Instead, it may reflect early association events such as dimerization or other local rearrangements required for primary nucleation, followed by consolidation into stable intermolecular contacts. Aggregation that preserves a largely native-like fold while establishing cross-β order may reduce recognition by cellular quality-control systems that preferentially target globally unfolded or strongly destabilized states. This provides a plausible framework for how YB-1 derived assemblies could persist under stress and during age-associated proteostasis decline. Full article

Honey authenticity control remains analytically challenging due to the complexity of its matrix and the increasing sophistication of adulteration practices. While chromatographic, spectrometric, and isotopic methods provide high confirmatory accuracy, their routine application is constrained by cost, time, and infrastructure requirements. In this context, fluorescence spectroscopy has emerged as a rapid, non-destructive, and cost-efficient screening approach capable of capturing subtle matrix-level compositional variations. This review critically evaluates the application of steady-state and excitation–emission matrix (EEM) fluorescence in honey quality and authenticity assessment. Fluorescence is positioned within tiered analytical frameworks as a first-line or intermediate screening tool preceding confirmatory chromatographic or NMR-based analyses. Emphasis is placed on intrinsic fluorophore domains, excitation–emission measurement strategies, and chemometric interpretation, including multiway analysis and supervised classification models. Recent developments in portable LED-based systems, laser-induced fluorescence, nanoparticle-based probes, and data-fusion strategies are discussed alongside key limitations related to matrix effects, spectral overlap, reproducibility, and model transferability. The review provides a structured framework for the strategic integration of fluorescence spectroscopy into contemporary honey authentication workflows. Full article

The aim of this work is to prepare and characterize a composite adsorbent comprising the hydrophilic ionic liquid 1-ethyl-3-methylimidazolium acetate [EMIM-Ac] composite supported on mesoporous silica gel for application in adsorption heat storage systems. Water adsorption/desorption isotherms were measured gravimetrically at T = 40, 50, 70 °C across a relative humidity (RH) range of 0–0.8, demonstrating a high adsorption capacity (up to 0.71 g/g at 50 °C and RH = 0.8, for a 50 wt % [EMIM-Ac] loading). Full process reversibility and negligible ad/desorption hysteresis were also verified. Thermal stability of the prepared silica/[EMIM-Ac] composites was confirmed up to approximately T = 200 °C. Structural stability of samples subjected to repeated ad/desorption aging cycles was verified via FT-IR, High-Resolution Solid-State NMR, and Time-Domain NMR spectroscopy. Finally, the thermodynamic analysis based on adsorption experimental data indicated that the silica/[EMIM-Ac] composite is highly suitable for adsorption heat storage, providing a volumetric density of 600–920 MJ/m³ at regeneration temperatures below 100 °C. Full article

This study reports the synthesis and catalytic evaluation of a series of imidazolium-based polymeric ionic liquids (PILs) for the cycloaddition of CO₂ to epichlorohydrin (ECH). The synthesized catalysts include homopolymers, poly(3-hydroxyethyl-1-vinylimidazole chloride) (p[HVIm][Cl]) and poly(3-carboxymethyl-1-vinylimidazole chloride) (p[CMVIm][Cl]), and their block copolymers with polystyrene, synthesized for the first time, pS-b-p[HVIm][Cl] and pS-b-p[CMVIm][Cl]. Structural characterization by NMR, IR spectroscopy, and gel permeation chromatography confirmed the successful synthesis. The block copolymers exhibited a low polydispersity index (PDI 1.1–1.2), which is indicative of homogeneous chain lengths and the propensity to form ordered nanostructures, whereas the homopolymers showed higher PDI (2.4–2.9). Catalytic testing at 90 °C and 1 MPa CO₂ for 4 h revealed a clear activity trend: p[CMVIm][Cl] < p[HVIm][Cl] < pS-b-p[CMVIm][Cl] < pS-b-p[HVIm][Cl], with conversions exceeding 75% for all catalysts and a maximum of 82.69% for pS-b-p[HVIm][Cl]. These results demonstrate that the catalytic performance of PILs is governed by a synergistic interplay between the local chemical functionality of the ionic moiety and the overall polymer architecture. Based on these results, the synthesized polymeric ionic liquids, particularly pS-b-p[HVIm][Cl], demonstrate strong potential for creating multifunctional materials. Their ability to self-assemble into ordered nanostructures with distinct hydrophobic and hydrophilic domains provides a foundational architecture for combined gas separation and catalysis. The observed “micellar catalytic effect”, which enhances local reagent concentration near active sites, could be leveraged in a membrane reactor to simultaneously capture and convert CO₂ directly within the membrane. This integrated “separation–reaction” approach represents a promising strategy for advancing circular carbon economy technologies. Full article

The use of styrylium dyes as organic nonlinear optical materials in many photonics domains has been the subject of research for decades. It has been noted that over time, research has also looked into the biological activity of styrylium dyes, namely their antibacterial effects, as well as attempts to establish links between structure and property by choosing particular structural pieces. These investigations’ scope is still very limited. Therefore, our main goal was to synthesize a styrylium compound with antimicrobial potential. A novel styrylquinolinium compound (D) was synthesized using Knoevenagel condensation. Spectroscopic techniques, including IR, 1D and 2D NMR (COSY, HSQC, and HMBC), HRMS spectra, and X-ray analysis, were used to confirm its structure. The antimicrobial and anti-inflammatory activity of the compound was assessed. The compound was found to have very good antimicrobial activity against five Gram-positive strains, three Gram-negative strains, and fungi. The most pronounced effect of the compound was against Escherichia coli and Pseudomonas aeruginosa. The compound’s anti-inflammatory activity was evaluated through its ex vivo immunohistochemistry. DFT calculations, such as geometry optimization, Molecular Electrostatic Potential (MEP), HOMO–LUMO, reactivity parameters and molecular docking simulation were applied to investigate the electronic features of the compound and confirm the biological activity. The compound (D) demonstrated a promising antibacterial and immunomodulatory profile. Its ability to induce IL-1β and at the same time moderately reduce NOS3 can be considered as a controlled adaptation of the immune response, especially in cases requiring local immune activation. Docking simulation revealed that (D) binds effectively to the active site of the bacterial protein, supporting the experimental findings of the compound’s antibacterial activity. Full article

UV-C radiation has emerged as a germicidal agent against pathogens, particularly following the COVID-19 pandemic. While UV-C effectively reduces cross-contamination in hospitals, it induces photodegradation in polymer devices, potentially damaging and posing risks to patient safety. Therefore, it is crucial to detect the effects of UV-C photodegradation on early stages, as well as the effects of prolonged UV-C exposure. In this study, we investigated the UV-C photodegradation (254 nm, 471 kJ/mol) of isotactic polypropylene homopolymer (PP), commonly used in medication packaging. The impact of UV-C on PP was evaluated through rheology and infrared spectroscopy. Surface energy was measured by the contact angles formed by drops of water and diiodomethane. The effects of photodegradation on the polymer’s morphology were examined using scanning electron microscopy, and the melting temperature and crystallinity by differential scanning calorimetry. Lastly, the effect of UV-C on molecular mobility was studied using ¹H Time Domain Nuclear Magnetic Resonance (¹H TD-NMR). These techniques proved to be valuable tools for identifying the early stages of UV-C photodegradation, and ¹H TD-NMR was a sensitive method to identify the chain branching as a photodegradation product. This study highlights the impact of UV-C on PP photodegradation and hence the importance of understanding UV-C-induced degradation. Full article

This study investigates the elemental composition of magnetic nanoparticles (MNPs) in eleven wildland–urban interface (WUI) fire ashes, including one vegetation, six structural, and four vehicle ashes, along with three fire-impacted soil samples. The WUI fire ash samples were collected following the 2020 North Complex (NC) Fire and Sonoma–Lake–Napa unit (LNU) Lightning Complex Fire in California. Efficiency of magnetic separation was confirmed via Time-Domain Nuclear Magnetic Resonance (TD-NMR); the relaxometry showed that the transverse relaxation rate R₂ decreased from 2.02 s⁻¹ before separation to 0.29 s⁻¹ after separation (ΔR₂ = −1.73 s⁻¹; −86%), due to the removal of magnetic particles. The particle number concentrations, size distributions, and elemental compositions (and ratios) of MNPs were determined using single particle-inductively coupled plasma–time-of-flight-mass spectrometry (SP-ICP-TOF-MS). The major types of nanoparticles (NPs) detected in the magnetically separated MNPs were Fe-, Ti-, Cr-, Pb-, Mn-, and Zn-bearing NPs. The iron-bearing NPs accounted for 3.2 to 83.5% of the magnetically separated MNPs, and decreased following the order vegetation ash (77.4%) > soil (63.2–69.9%) > structural (3.2–83.5%) ash. The titanium-bearing NPs accounted for 3.3 to 66.1% of the magnetically separated MNPs, and decreased following the order vehicle (14.1–66.1%) > structural (3.5–36.4%) > vegetation (3.3%) ash. The majority of the detected NPs in the fire ashes occurred in the form of multi-metal (mm) NPs, attributed to the presence of NPs as heteroaggregates and/or due to the sorption of metals on the surfaces of NPs during combustion. However, a notable fraction (3–91%) of the detected NPs occurred as single-metal (sm) NPs, particularly smFe-bearing NPs, which accounted for 48 to 91% of all the Fe-bearing particles in the magnetically separated MNPs. The elemental ratios (e.g., Al/Fe, Ti/Fe, Cr/Fe, and Zn/Fe) in the magnetically separated MNPs from structural and vehicle ashes were higher than those in the soil samples and vegetation ashes, indicating enrichment of metals in magnetically separated NPs from vehicle and structural ashes compared to vegetation ash. Overall, this study demonstrates that the MNPs generated by WUI fire ash are associated with potentially toxic elements (e.g., Cr and Zn), exacerbating the environmental and human health risks of WUI fires. This study also highlights the need for further research into the properties, environmental fate, transport, and interactions of MNPs with biological systems during and following WUI fires. Full article

In this work, bare copper oxide-based catalysts were synthesized and evaluated for their dual (photo)catalytic activity in two model reactions: hydrogen generation via formic acid decomposition (FAD) and the photocatalytic hydroxylation of benzene to phenol. Catalysts were prepared from copper nitrate and copper acetate precursors and calcined for either 10 min or 2 h. Their structural and surface properties were characterized by wide-angle X-ray diffraction (WAXD), Raman spectroscopy, and BET surface area analysis. FAD was conducted under mild thermal conditions and monitored via ¹H NMR spectroscopy. At the same time, benzene hydroxylation was performed under UV irradiation and analyzed by gas chromatography (GC) and high-performance liquid chromatography (HPLC). All synthesized catalysts outperformed commercial CuO in the selective oxidation of benzene. The nitrate-derived sample calcined for 10 min (NCuO 10 min) achieved the best performance, with a phenol yield of ~10% and a selectivity of up to 19%, attributed to improved surface properties and the presence of Cu(I) domains, as indicated by Raman spectroscopy. For FAD, complete conversion of formic acid was achieved at low temperatures, with selective H₂ and CO₂ evolution and complete suppression of CO, even under short reaction times and low catalyst loadings. These results demonstrate the potential of nitrate-derived CuO catalysts as versatile, dual-function materials for sustainable applications in selective aromatic oxidation and low-temperature hydrogen generation, without the need for noble metals or harsh conditions. Full article

A highly efficient method was successfully applied for the first time to the functionalization of well-defined chlorinated silsesquioxanes with a range of thiols. Thiolation was rapid (2 to 4 h), quantitative, with complete conversion of the reactants and full chemoselectivity, and proceeded under mild conditions (room temperature). This “click chemistry” approach facilitated the preparation of nine novel compounds, with good to excellent isolated yields (64–92%). The structures and purities of these compounds were comprehensively confirmed using multiple analytical techniques, including ¹H, ¹³C, and ²⁹Si NMR spectroscopy, elemental analysis, and mass spectrometry. Thermogravimetric analysis (TGA) further demonstrated that the synthesized compounds exhibited excellent thermal stability. These characteristics suggest their potential for applications in various domains of science, technology, and medicine. Full article

Determining the technological quality of fresh meat pieces is essential in the meat industry to ensure the production of high-quality products. For this purpose, nuclear magnetic resonance (NMR) is a non-destructive and non-invasive technique that appears as an alternative to traditional methodologies. The objective of this work is to determine the potential of magnetic resonance imaging (MRI) and time-domain (TD-NMR) relaxometry for determining the physicochemical characterization of fresh hams with different industrial destinations (both fresh and cured products, such as dry-cured ham). For this study, the biceps femoris, semimembranosus, and semitendinosus muscles of 20 fresh hind legs from white pigs, classified into four categories according to their fat content, were analyzed. The semitendinosus muscle was selected as a model, and positive and negative correlations were obtained between different physicochemical parameters and the longitudinal (T1) and transverse (T2) relaxation times obtained by MRI and TD-NMR. Regression models using T1 and T2 were also developed to predict the muscle water-holding capacity (WHC) and drip loss, using high, medium, and low magnetic field NMR (R² > 0.80). Therefore, MRI and TD-NMR could be considered as highly suitable and accurate non-destructive techniques for the WHC determination in the meat industry. Full article

Polyamides (PAs) are widely used as barrier materials in offshore oil and gas (O&G) equipment due to their mechanical strength and chemical resistance. However, long-term exposure to hydrogen sulfide scavengers (H₂S-SCVs) may significantly affect their physicochemical properties. Previous studies using thermal analysis and ¹H time-domain NMR (¹H TD-NMR) suggest that ethoxylated H₂S-SCVs impose molecular constraints, increasing the glass transition temperature (T_g) and reducing chain mobility above T_g. The present study builds upon these findings using a multi-technique analytical approach, including FTIR, Raman, ¹H DQ-TD-NMR, and ¹³C solid-state NMR (ssNMR), to provide a more comprehensive understanding of the molecular alterations in PA materials. The results clearly demonstrate that H₂S-SCV exposure leads to the progressive exudation of plasticizers from the PA matrix. This plasticizer loss is a key factor contributing to the observed shift in Tg and the reduction in molecular mobility. ¹H DQ-TD-NMR data confirmed an increase in the density of dynamically constrained chains over time and allowed for the characterization of heterogeneity in these constraints throughout the PA matrix. Moreover, ¹³C ssNMR spectra revealed the presence of immobilized H₂S-SCV chemical groups within the polymer matrix, strongly supporting the early statement that the mobility constraints observed in ¹H DQ-TD-NMR are associated with the formation of crosslinks induced by the H₂S-SCV: H₂S-SCV acts as a crosslinking agent. Taken together, our findings indicate that both plasticizer loss and H₂S-SCV-induced crosslinking contribute significantly to the microstructural evolution of PAs when exposed to ethoxylated H₂S-SCVs, offering important insights into their degradation mechanisms and long-term behavior in aggressive operational environments. Full article

Background: There are a few very specific inflammation biomarkers in blood, namely lipoprotein NMe⁺ signals of protein clusters (GlycA and GlycB) and a composite resonance of phospholipids (SPC). The relative integrals of these resonances provide clear indication of the unique metabolic changes associated with disease, specifically inflammatory conditions, often related to serious diseases such as cancer or COVID-19 infection. Relatively complicated, yet very efficient experimental methods have been introduced recently (DIRE, JEDI) to suppress the rest of the spectrum, thus allowing measurement of these integrals of interest. Methods: In this study, we introduce a simple alternative processing method using CRAFT (Complete Reduction to Amplitude-Frequency Table), a time-domain (FID) analysis tool which can highlight selected subsets of the spectrum by choice for quantitative analysis. The output of this approach is a direct, spreadsheet-based representation of the required peak amplitude (integral) values, ready for comparative analysis, completely avoiding all the convectional data processing and manipulation steps. The significant advantage of this alternative method is that it only needs a simple water-suppressed 1D spectrum with no further experimental manipulation whatsoever. In addition, there are no pre/post processing steps (such as baseline and/or phase), further minimizing potential dependency on subjective decisions by the user and providing an opportunity to automate the entire process. Results: We applied this methodology to horse serum samples to follow the presence of inflammation for cohorts with or without OCD (Osteochondritis Dissecans) conditions and find diagnostic separation of the of the cohorts through statistical methods. Conclusions: The powerful and simple CRAFT-based approach is suitable to extract selected biomarker information from complex NMR spectra and can be similarly applied to any other biofluid from any source or sample, also retrospectively. There is a potential to extend such a simple analysis to other, previously identified relevant markers as well. Full article