Search Results (4,075)

Two hemostatic bionanocomposite dressings were developed using natural, semi-natural (or semi-synthetic) and synthetic polymers. The first system consisted of chitosan (CS), polyvinyl alcohol (PVA), and carboxymethyl cellulose (CMC) (CS/PVA/CMC), while the second was based on CS, PVA, and starch (SR) (CS/PVA/SR). Zinc oxide (ZnO) nanoparticles and bicyclic monoterpene camphor (CP) ketone were incorporated as bioactive agents in order to enhance antimicrobial and hemostatic performance. FTIR spectroscopy confirmed the successful solvent casting synthesis of the dressings and the interactions between the biopolymers and additives. XRD analysis indicated a predominantly amorphous structure, while SEM images and EDS analysis revealed uniform dispersion of ZnO particles within the polymer matrices without aggregation. Furthermore, the CS/PVA/CMC-1ZnO/CP sample exhibited a water sorption of 12,666 ± 126%, while CS/PVA/SR-1ZnO/CP reached 7013 ± 215%. ZnO incorporation also improved mechanical performance, with CS/PVA/SR-2ZnO/CP displaying the highest tensile strength (39.18 ± 0.2 MPa) and elongation at break (9.54 ± 1.04%). ZnO incorporation also led to a concentration-dependent increase in antibacterial activity, with SR-based dressings achieving near-complete bacterial reduction at higher ZnO loadings. All the dressings demonstrated good biocompatibility, while CS/PVA/SR-1ZnOCP showed the fastest clotting time (420s ± 40), highlighting its potential for hemostatic applications. Full article

Four algal adsorbents were prepared from two types of green sea algae (Ulva lactuca and Ulva pertusa), either by treatment with concentrated sulfuric acid or without treatment. A comparative study of Au(III) adsorption in an HCl medium was performed. While both untreated adsorbents showed good performance at low HCl concentrations, the treated adsorbents achieved quantitative adsorption and high selectivity for Au(III) across a broad range of HCl concentrations. The adsorption of Au(III) onto the algal biomass adsorbents followed the typical Langmuir monolayer adsorption model. At an HCl concentration of 0.010 M, the maximum adsorption capacities were 1.14, 0.86, 6.57, and 6.28 mol kg^–1 for DUL, DUP, TUL, and TUP, respectively. A kinetic study conducted at different temperatures was consistent with the pseudo-first-order kinetic model and enabled estimation of the activation energy of the adsorption reaction. Structural changes before and after treatment were analyzed using FT-IR spectroscopy. Confirmation of Au(III) adsorption and its subsequent reduction to the elemental state was achieved through XRD and SEM/EDX analyses as well as digital imaging of the Au-loaded adsorbents. Finally, the adsorbed and reduced Au was successfully desorbed using an acidic thiourea solution. Full article

Terahertz radiation exhibits significant potential for communications, imaging, and spectroscopy. However, the development of efficient and low-cost THz detectors remains challenging due to limitations such as insufficient sensitivity, slow response speed, and poor room temperature stability. This work presents an innovative quasi-2D perovskite/Weyl semimetal (Co₃Sn₂S₂) heterojunction THz detector that combines complementary material properties via band engineering. The device achieves a remarkable responsivity of 374.15 A/W, a specific detectivity of 6.27 × 10¹¹ cm·Hz^1/2·W⁻¹, and a noise-equivalent power of 0.29 pW·Hz^−1/2 at 0.1 THz. This performance stems from the strong THz absorption of the perovskite layer combined with the high carrier mobility and topological surface states of the Co₃Sn₂S₂, which collectively enable ultrafast carrier extraction and suppressed interfacial recombination. This heterojunction design offers a novel strategy for high-performance terahertz detection and facilitates its integration into next-generation portable, integrated devices. Full article

High-throughput and compact volume phase holographic (VPH) grating transmission spectrometers are widely employed in scientific research, agriculture, and industrial applications. Conventional transmission spectrometers generally adopt a fixed configuration and therefore have limitations in simultaneously achieving high spectral resolution and broad wavelength coverage. To address the limited tunability of transmission spectrometers, this work presents the theoretical analysis and experimental validation of a transmission spectrometer incorporating a novel catadioptric grating assembly, which consists of a transmitting VPH and a planar reflector. A catadioptric system is a combination of reflective (catoptric) and refractive (dioptric) elements. In the proposed configuration, a VPH grating and a plane mirror arranged at a fixed 90° angle form the catadioptric dispersion module. Synchronous rotation of this assembly enables wavelength scanning. The structure ensures that the diffracted ray along the optical axis of the imaging lens maintains the Bragg condition across the scanning range, thereby preserving maximum diffraction efficiency. The optical configuration and structural parameters of the spectrometer were theoretically derived, and a prototype spectrometer with an f-number of 1.8 employing a 2400 g/mm grating was constructed. Measurements demonstrate that, when the rotation angle is tuned from 30.5° to 50.5°, the accessible spectral range covers from 410 nm to 650 nm. Spectral response measurements using a tungsten–halogen light source confirm that the spectrometer maintains an acceptable diffraction efficiency across the entire tuning range. The measured spectral resolution is 0.1 nm at 626 nm with a 2400 g/mm grating and 0.18 nm with a 1500 g/mm grating. The spectrometer was further applied to fiber-enhanced gas Raman spectroscopy, where it successfully resolved the closely spaced Raman peaks of CH₄ and C₂H₆ that are difficult to distinguish using conventional compact spectrometers. These results demonstrate that the proposed tunable catadioptric spectrometer simultaneously provides excellent wavelength tunability and high spectral resolution. Full article

This study investigates the effect of complex nanomodification combined with the simultaneous application of magnetic fields and mechanical vibration on the structure formation and performance properties of medium-alloy steel 40CrNi3MoV. Improving the structural homogeneity and operational characteristics of such steels remains an important task due to their widespread use in components operating under severe loading and wear conditions. The introduction of the nanostructured modifier InSteel-7 at a concentration of 0.03%, together with simultaneous magnetic and vibrational treatment of the melt, resulted in pronounced structural homogenization and grain refinement. Quantitative metallographic analysis using Thixomet Pro image analyzer revealed a significant refinement of the dendritic structure, with the secondary dendrite arm spacing decreasing from 73.9 μm to 27.9 μm. X-ray phase analysis confirmed the preservation of phase composition while indicating increased structural uniformity of the BCC matrix. Energy-dispersive spectroscopy and elemental micro-mapping demonstrated high chemical purity of the alloy and a uniform distribution of the modifier components. The combined treatment significantly improved the mechanical and tribological characteristics of the material. The average hardness increased from 390 HV to 510 HV, while tribological tests showed a reduction in wear track depth from 5.16 μm to 0.87 μm and a decrease in surface roughness from Ra 2.13 μm to 0.20 μm, indicating enhanced wear resistance. Full article

Alpha-ketoglutarate (aKG) is a central intermediate of cerebral energy metabolism and a precursor for glutamate synthesis in the brain. Alterations in aKG metabolism occur in pathological contexts, including isocitrate dehydrogenase (IDH) mutant astrocytomas and oligodendrogliomas, in which mutant IDH converts aKG to the oncometabolite 2-hydroxyglutarate. Given its central role in brain metabolism, non-invasive interrogation of aKG-dependent metabolic flux is needed. Hyperpolarized (HP) ¹³C MR enables real-time visualization of metabolic conversion by transiently enhancing signal intensity by several orders of magnitude. Leveraging this approach, we report the first-in-human feasibility and safety study of HP [1-¹³C]aKG MR spectroscopy in the healthy brain (n = 3). A standard operating procedure (SOP) was developed for sterile [1-¹³C]aKG dose production, achieving reproducible polarization levels averaging 30.5 ± 2.2%. Following intravenous administration, time-resolved ¹³C spectra in healthy volunteers demonstrated the detection of HP aKG resonance and a measurable downstream glutamate signal, consistent across repeat acquisitions, with a delayed temporal profile relative to aKG observed in a representative dataset. Although performed in healthy volunteers, these results establish feasibility for HP [1-¹³C]aKG metabolic imaging to open a new window into normal and pathological brain cellular metabolism. Full article

Honey adulteration remains a major challenge for ensuring food authenticity and sustainable quality control. In this study, near-infrared (NIR) spectroscopy and hyperspectral imaging (HSI) were comparatively evaluated as green, non-destructive analytical techniques for the discrimination of pure and adulterated honey using chemometric modeling. A total of 180 honey samples, including pure and adulterated samples with agave syrup, sucrose syrup, or water at varying concentrations, were analyzed using two NIR platforms (MicroNIR™ 1700 and NIRS™ DS2500) and an HSI system (Micro-Hyperspec^® NIR camera). Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were applied for exploratory analysis and supervised classification, respectively. Both techniques enabled effective discrimination between pure and adulterated honey. The results demonstrated that the two NIR platforms achieved superior classification performance: the MicroNIR™ 1700 yielded overall sensitivities, specificities, and accuracies of 100%, respectively. While the HSI system provided complementary spectral-spatial information, its performance and that of the NIRS™ DS2500 were slightly lower, with an overall accuracy of 93.10%, particularly at low levels of adulteration (≤10%). Overall, these results demonstrate that NIR-based spectroscopy is a reliable, fast, non-destructive, and eco-friendly analytical tool for testing the authenticity of honey. The portable NIR system, in particular, provides a cost-effective and field-deployable solution for in situ quality control. Integrating it into routine quality control practices could help prevent food fraud, protect consumer trust, and promote sustainable industry development. Full article

This study developed a microemulsion system based on diatomaceous earth (DE) for the topical delivery of resveratrol. The microemulsions were prepared using pseudo-ternary phase diagrams. A 4:1 ethanol:virgin coconut oil ratio resulted in a larger microemulsion region than a 3:1 ratio. Two formulations with oil (ethanol:virgin coconut oil, 3:1):Cremophor RH40:water ratios of 1:5:4 (ME1) and 2:5:3 (ME2) were selected for resveratrol loading and subsequently combined with DE at ratios of DE:microemulsion (DE:ME) 0.5:1, 0.5:2, and 0.5:3. The transmission electron microscopy images demonstrated the different microstructures of the microemulsions. Rheological analysis revealed an increase in storage modulus and a decrease in the linear viscoelastic region with increasing DE concentration, particularly in ME1. Differential scanning calorimetry showed disruption of boundary water following DE incorporation. Fourier-transform infrared spectroscopy indicated primarily physical interactions between resveratrol and the DE:ME system. DE:ME demonstrated high resveratrol content, approaching 100%. DE:ME1 0.5:2 significantly enhanced resveratrol permeation, resulting in a 3-fold increase compared with the microemulsion alone after 8 h. DE:ME1 0.5:2 and DE:ME2 0.5:3 enhanced the photostability of resveratrol and the formulations remained stable after storage at 40 °C for 6 months. The DE:ME system maintained its cellular uptake capability, preserved the biological activity of resveratrol, and exhibited low cytotoxicity in human keratinocytes, with cell viability remaining above 70%. These results highlight the potential of DE-based systems for incorporating microemulsions of low-water soluble photo-sensitizing substances in topical drug delivery applications. Full article

Due to biodegradability, functionalization, and sustained release, polymer-based films are widely used in different industries. This study explores a bioactive emulsion-based film obtained using high-methoxy pectin (HMP), Origanum onites L. essential oil, and a hydroalcoholic extract of Thymus vulgaris L., prepared using various emulsion recipes. The emulsions obtained were applied to cellulose supports intended for topical applications. Bioactive textiles were analyzed using SEM-EDS elemental mapping, ATR FT-IR spectroscopy, biocompatibility assessment, antimicrobial activity assays, and analysis of comfort indices. SEM images of textile supports treated with bioactive emulsions confirmed the creation of a film surface and that the homogeneity of the film increases with increasing amount of glycerin, which acts as a plasticizer. Infrared spectra combined with their second derivatives and PCA indicate the presence of oregano essential oil, thyme extract, and pectin on the surface of the cotton. The biocompatibility evaluation of functionalized cotton supports revealed minimal cytotoxic effects on HaCaT human keratinocytes after 24 h of exposure. The results of the analyses showed that bioactive textile supports also exhibit antimicrobial activity. Therefore, the active emulsions with pectin, oregano essential oil, and hydroalcoholic extract of thyme provide biocompatible and antimicrobial active films by applying on cellulosic supports. Full article

Background/Objectives: The oral administration of donepezil has been shown to have common side effects due to systemic drug delivery, with fluctuations in blood and brain donepezil concentrations. Therefore, we obtained nanostructured lipid carriers loaded with donepezil (donepezil–NLC) for nose-to-brain targeting. Methods: The obtained NLCs were characterized by measurements of particle size, the polydispersity index, zeta potential, encapsulation efficiency, atomic force microscopy, Differential Scanning Calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and in vitro release studies. Plasma and brain pharmacokinetic studies in Wistar rats were carried out to determine brain targeting. Results: Donepezil–NLC showed low polydispersity and nanometric size, high zeta potential, and high drug entrapment efficiency. Microscopy images showed spherical particles with regular surfaces. Thermal analysis, X-ray diffraction, and FTIR-ATR suggested the formation of an amorphous lipid matrix and the incorporation of donepezil molecularly dispersed within the lipid matrix. In vitro drug release studies demonstrated a biphasic drug release pattern with an initial burst followed by sustained release, with results better fitted to the Korsmeyer–Peppas model (n-value > 0.5). Following the nasal administration of donepezil–NLC, brain pharmacokinetic studies in Wistar rats demonstrated a significant improvement in bioavailability. Compared to the intravenous injection of donepezil, the AUC^0–ꝏ value was 10.5-fold higher. Drug targeting efficiency and direct transport percentage showed extremely higher values, suggesting nose-to-brain targeting after donepezil–NLC intranasal administration. Conclusions: Donepezil–NLC has proven to be an efficient drug delivery system for the nose to the brain, which may reduce systemic toxicity and improve Alzheimer’s therapy with low doses of donepezil and fewer adverse effects. Full article

Magic lantern slides are fragile objects consisting of transparent images depicted on thin glass plates to be projected by magic lanterns. Despite their widespread presence in archives and museums, these collections are often undervalued and understudied. The Portuguese Cinematheque holds the most extensive collection of slides in Portugal. This article presents the first preventive conservation case study focused on the collection of painted slides, reflecting on the general origins of this collection, examining the challenges faced by caretakers when adapting historical buildings to accommodate collections of this nature. Environmental monitoring of light and radiation, temperature, and relative humidity in storage and exhibition rooms was combined with ultraviolet-visible spectroscopy to measure the fading of one of the most light-sensitive colours identified in these slides in previous studies, the pink eosin-based lake, by comparing a slide exhibited under the measured light conditions with one kept in storage during the same period. The results identified damaging light exposure in display areas with illuminance values far above the recommended levels for these materials, and significant RH fluctuations in both spaces. These conditions are consistent with deterioration factors known to affect the material that composes these fragile media (e.g., light-sensitive painting materials and organic frames, and unstable glass). This study also showcases how raising awareness on the fragility of this heritage stimulated discussions and encouraged small and feasible changes that can positively impact its preservation. Full article

Background and Purpose: Neurological injury remains a major complication of pediatric cardiac surgery and is closely related to alterations in cerebral blood flow during extracorporeal circulation (ECC). However, the real-time assessment of cerebral perfusion under these conditions has been limited by the lack of magnetic resonance (MR)-compatible perfusion systems. The aim of this pilot feasibility study was to establish a porcine model enabling simultaneous cardiopulmonary bypass (CPB) and real-time MR-based assessment of cerebral blood flow during simulated pediatric cardiac surgery. Methods: We conducted a pilot study on 11 Duroc pigs (14.6 ± 1.4 kg BW), designed in iterative cycles. The experimental setup included an MR-conditional heart-lung machine and a surgical protocol closely mimicking pediatric cardiac surgery. After the initiation of CPB and hemodynamic stabilization, animals were cooled to target temperatures (20 °C or 28 °C) depending on the perfusion strategy. Structural and functional MRI, including phase-contrast imaging, arterial spin labeling, diffusion-weighted imaging, and MR spectroscopy, were performed during cooling and rewarming. Procedural feasibility, technical challenges, and optimization strategies were systematically documented. Results: The study successfully established a reproducible porcine model enabling MR imaging during extracorporeal circulation. Key technical challenges, including vascular access, cannulation of the ascending aorta, and blood volume management, were identified and addressed through the iterative refinement of the surgical and perfusion protocols. The use of the Seldinger technique significantly improved cannulation safety and reduced blood loss. Stable CPB conditions and target hypothermic temperatures were achieved in successfully cannulated animals. MRI acquisition during CPB was feasible, providing simultaneous structural and functional assessment of cerebral perfusion. Representative imaging data demonstrate the capability of the model to capture cerebral hemodynamics in real time. Conclusions: This pilot study establishes a novel MR-compatible porcine model for the real-time assessment of cerebral blood flow during extracorporeal circulation. The platform provides a robust foundation for future quantitative investigations of cerebral perfusion, mechanisms of brain injury, and neuroprotective strategies in pediatric cardiac surgery. Full article

Background/Objectives: Goupi plaster (GP) is a traditional black plaster composed of a biphasic fibrous–oil matrix containing multiple bioactive compounds, and it has been widely used for the treatment of musculoskeletal disorders. Representative active compounds include sinomenine, osthole, cinnamaldehyde, and imperatorin, which exhibit anti-inflammatory and analgesic effects. However, due to its heterogeneous matrix structure and multi-component nature, the pharmaceutical delivery behavior of GP remains difficult to evaluate using conventional methods. Therefore, this study aimed to establish an integrated structure–release–permeation–pharmacokinetic evaluation framework to systematically characterize the transdermal delivery behavior of GP. Methods: GP was evaluated using multi-level analysis, including microstructural imaging (FESEM), in vitro release, ex vivo skin permeation, and in vivo dual-site microdialysis. Four representative bioactive compounds (sinomenine, osthole, cinnamaldehyde, and imperatorin) were selected as marker compounds. Release data were fitted to kinetic models, and structure–release relationships were examined using the Higuchi release constant (k_h). Skin-barrier alterations were assessed by attenuated total reflectance–Fourier transform infrared spectroscopy (ATR–FTIR) and differential scanning calorimetry (DSC). Local concentrations in subcutaneous (SC) and intra-articular (IA) compartments were measured by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) to explore potential in vitro–in vivo correlation (IVIVC). Results: FESEM revealed a fibrous–oil network structure. GP exhibited sustained, diffusion-dominated release, with k_h = 0.9908–0.9977 and Korsmeyer–Peppas (K–P) release exponents (n) = 0.61–0.66, differing from active pharmaceutical ingredient (API) controls. Fiber area fraction and fiber length density showed negative correlations with k_h (r = −0.91 to −0.99); ex vivo permeation profiles varied among compounds, and ATR–FTIR and DSC analyses showed moderate changes in skin-barrier properties. Dual-site microdialysis demonstrated sustained local exposure, and a positive relationship was observed between in vitro release and in vivo concentrations. Conclusions: This study establishes an integrated structure–release–permeation–pharmacokinetic evaluation framework for traditional black plaster systems. The observed IVIVC is descriptive rather than predictive, reflecting a trend-level association under the current experimental conditions. These findings highlight the importance of integrating in vitro release, skin permeation, and local pharmacokinetics for understanding drug delivery behavior in complex transdermal matrix systems, and provide a methodological basis for quality consistency evaluation of traditional black plaster formulations. Full article

Native cellulose I can be converted into crystalline polymorphs II and III_I, while cellulose II can be further converted into III_II through chemical treatments that induce significant structural, physical, and chemical changes. Accurate identification and differentiation of these polymorphs is essential for predicting fiber reactivity and processing behavior, but current methods are time-consuming. This study demonstrates the potential of near-infrared hyperspectral imaging (HSI-NIR) combined with linear discriminant analysis as a rapid, non-destructive tool for polymorph discrimination. Cellulose I, II, III_I, and III_II were produced from bleached kraft pulps of eucalyptus and pine and from cotton linters using NaOH (20% w/v) and ethylenediamine treatments. HSI-NIR successfully differentiated polymorphs based on spectral signatures in the 1480–1600 nm range, regardless of botanical source. Complementary characterization by XRD confirmed polymorph conversions, showing crystallinity reductions of 10–15% for cellulose I→II and I→III_I conversions, with crystallite size decreasing from 7.2 nm (cotton CI) to 3.2–3.4 nm in all CIII_II samples. XPS analysis revealed increased C-O surface accessibility in cellulose II and III, with complete disappearance of COOH groups in cellulose III samples. These results establish HSI as a promising screening tool for cellulose polymorph identification (>95% classification accuracy) and provide comprehensive baseline data on structural and chemical transformations that govern fiber reactivity in chemical and enzymatic processes. Full article

Floating rafts are thin, flat mineral layers that precipitate at still air–water interfaces. They are composed of calcite, aragonite, vaterite, gypsum, trona, carnallite, and/or halite. Floating rafts present a flat surface at the top in contact with air, and a rough surface at the bottom, which develops as they grow into the water. In this work, we describe floating rafts from hypersaline environments using imaging and analytical microscopy techniques. The four rafts studied consist of interconnected polycrystalline grains. Scanning electron microscopy (SEM) showed that the top surfaces were flat, whereas in the bottom surfaces, the grains protrude into the water. High magnification revealed nanoparticles arranged in stacks, suggesting growth through the organized agglutination of nanocrystals. Electron diffraction of two of the rafts indicates that they consist of aragonite. Accordingly, electron energy-loss spectroscopy (EELS) shows the C K-edges characteristic of carbonates, along with O and Ca edges. Energy-dispersive spectroscopy (EDS) in the SEM also revealed a few Ca sulfate crystals on the bottom surface. In addition, the presence of cubic shapes indicates the presence of halite. We hypothesize that the genesis of these rafts is driven by evaporation of still water, which increases supersaturation at the very surface, leading to mineral nucleation at the air–water interface, where the activation energy is lower. Full article