Search Results (78)

Marine concrete engineering faces severe service environment challenges, including high hydraulic pressure, large stress, and serious penetration. The evaluation of the durability and safety of these structures depends directly on the damage mechanism of concrete materials submitted to high hydraulic pressures. This paper introduced the experimental research on the mechanical properties and the damage mechanism of concrete submitted to high hydraulic pressures. The permeability tests were carried out on concrete specimens under the effect of different hydraulic pressures (1.2 MPa, 2.4 MPa, 3.6 MPa) and durations (10 d, 20 d, 30 d), after which the compressive strength, micro-cracks, and the ultrasonic velocity were obtained and analyzed. The results show that under the effect of sustained high hydraulic pressure, the micro-cracks in concrete increase, the density decreases, and the harmful pores expand, resulting in a degradation in the mechanical properties of concrete. The damage to concrete is more severe at the near end of the hydraulic head than at the far end. The pore water pressure decays gradually with depth inside the concrete and expands inward when the outer layer of concrete is damaged. The conclusions will provide a scientific basis for the safety evaluation of marine concrete engineering. Full article

Accurate measurement of low-level radon concentrations in the environment is increasingly important for climate research, radon priority area delineation, and atmospheric studies. Adsorbent-based radon detectors offer high sensitivity but suffer from strong temperature dependence of radon adsorption and rapid degradation under humid conditions, limiting their applicability in long-term environmental monitoring. This work presents a universal design methodology for temperature- and moisture-compensated radon detectors based on hermetically packaged adsorbents enclosed by radon-permeable polymer foils. Analytical models describing the opposing temperature dependences of radon adsorption in adsorbents and radon permeability in polymers are combined to derive a general optimization criterion that minimizes temperature-induced response variations over a defined temperature range. The method is applicable to arbitrary combinations of adsorbent materials and polymer foils, provided their radon adsorption and permeability characteristics are known. The approach is demonstrated using activated carbon fabrics and common polymers (LDPE, HDPE, and polypropylene), for which optimal design parameters are identified. In addition, water vapor permeation through polymer foils is modeled to estimate moisture protection and permissible exposure durations under high humidity. The results demonstrate that appropriately designed compensation modules can significantly reduce temperature sensitivity while extending operational stability in humid environments, enabling next-generation high-sensitivity radon detectors suitable for environmental applications. Full article

The application of natural polysaccharides and their sulfated derivatives have already been successfully implemented in the pharmaceutical and food industries, in particular. The present study is concerned with modifying a predominant polysaccharide in the composition of spruce wood, galactoglucomannan (GGM), by sulfation via a urea-sulfamic acid complex in a 1,4-dioxane medium. By varying the sulfation process duration from 30 to 180 min, six novel GGM sulfate samples with different degrees of substitution (DS) of 0.4–1.2 were obtained and studied with a combination of modern physicochemical methods: elemental analysis, Fourier transform infrared (FTIR) spectroscopy, and gel permeation chromatography (GPC). It has been revealed that the sulfation of GGM proceeds without degradation of the main polymer chain, as evidenced by the shift in the main peak toward the high-molecular-weight region in the GPC curves. Moreover, modification of the polysaccharide leads to a significant transformation of the molecular conformation from a dense sphere to a random coil (α from 0.30 to 0.76). Furthermore, it has been determined that sulfate-substituted groups of the GGM tended to decrease the scavenging capacity of the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals. However, the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assay showed an increase in the free radical inhibitory capacity of sulfated polysaccharides. This is attributed to the structural and conformational properties of the polysaccharide sulfate derivatives. The maximum anticoagulant activity (ACA) of sulfated GGM (SGGM) is 21.19 ± 2.89 IU/mg and increases with increasing sulfation duration. Full article

Infrasound, physically defined as sound at frequencies below 20 Hertz, can travel long distances with minimal attenuation and permeate biological tissues due to its marked particle displacement and deep penetration. Generated by both natural phenomena and human-made systems, infrasound has drawn increasing scientific and public attention regarding its potential physiological and psychological effects. Experimental studies demonstrate that infrasound can modulate mechanosensitive structures at the cellular level, particularly pressure-sensitive ion channels such as PIEZO1 and TRPV4, leading to intracellular calcium influx, oxidative stress, altered intercellular communication, and in some settings, apoptosis. These responses vary according to sound pressure levels, frequencies, exposure duration, and tissue type. In the cardiovascular system, higher sound pressures have been associated with mitochondrial injury and fibrosis, whereas low sound pressures may exert context-dependent protective effects. In animal models, prolonged or intense exposure to infrasound has been shown to induce neuroinflammatory responses and memory impairment. Short-term studies in humans at moderate intensities have reported minimal physiological changes, with psychological and contextual factors influencing symptom perception. Occupational environments such as factories and agricultural settings may contain elevated levels of infrasound, underscoring the importance of systematic measurements and exposure assessments. At the same time, controlled infrasound stimulation has shown potential as an adjunct modality in bone repair and tissue regeneration, highlighting its dual capacity as both a biological stressor and a possible therapeutic tool. Overall, existing data indicate that infrasound may be harmful at chronic exposure depending on intensity and frequency, yet beneficial when precisely regulated. Future research should standardize exposure metrics, refine measurement technologies, and clarify dose–response relationships to better define the health risks and therapeutic applications of infrasound. Full article

Fiber-reinforced polymer (FRP) composites are increasingly used in civil, marine, offshore, and energy infrastructure, where components routinely experience temperatures above ambient conditions. While the design of these components is largely driven by fiber-dominated characteristics, the deterioration of shear properties can lead to premature weakening and even failure. Thus, the performance and reliability of these systems depend intrinsically on the response of interlaminar shear characteristics, in-plane shear characteristics, and flexure-based shear characteristics to thermal loads ranging from uniform and monotonically increasing to cyclic and spike exposures. This paper presents a critical review of current knowledge of shear response in the presence of thermal exposure, with emphasis on temperature regimes that are below T_g in the vicinity of T_g and approaching T_d. Results show that thermal exposures cause matrix softening and microcracking, interphase degradation, and thermally induced residual stress redistribution that significantly reduces shear-based performance. Cyclic and short-duration spike/flash exposures result in accelerated damage through thermal fatigue; steep thermal gradients, including through the thickness; and localized interfacial failure loading to the onset of delamination or interlayer separation. Aspects such as layup/ply orientation, fiber volume fraction, degree of cure, and the availability and permeation of oxygen through the thickness can have significant effects. The review identifies key contradictions and ambiguities, pinpoints and prioritizes areas of critically needed research, and emphasizes the need for the development of true mechanistic models capable of predicting changes in shear performance characteristics over a range of thermal loading regimes. Full article

Background/Objectives: Liver cancer is among the most frequent poor-prognosis malignancies worldwide, with currently insufficient effective treatment. The two-stage microwave hyperthermia using magnetic nanoparticles is a modern technique designed to specifically target tumor tissues and facilitate chemotherapy activation, with promising results from fundamental studies across various tumor types. The method consists of a first irradiation, performed before nano-assemblies administration. This is intended to sensitize the tumor by inducing a hyperthermic effect, leading to increasing blood supply, enhancing endothelial damage/permeation and inflammatory activation, with the final goal of improving the diffusion/retention of nano-assemblies in the tumor. Subsequently, the second microwave irradiation follows the injection in the hepatic artery and diffusion in the tumor of the activated nano-assemblies, to further determine a strong, but localized and focalized hyperthermic action. Nano-magnetic assemblies for hyperthermia accomplish the proposed chemo-thermal delivery, i.e., act per se on the tumor and also destabilize co-administered assemblies of nanoparticles loaded with chemotherapeutics, which would be consequently released locally in the most efficient way. This article aims to demonstrate the efficacy of this therapeutic approach in a rat liver model and its potential applicability in patients with liver tumors. Methods: Adult male Wistar rats were used to obtain liver samples, which were divided into three groups, each receiving a different hyperthermia protocol in terms of temperature (41–45 °C), duration, and co-administration of nanoparticles. Results: The most suitable exposure temperature for rat liver appears to be 42 °C, resulting in vacuolar degeneration lesions at the focal level. The effects of thermal conditioning do not appear to be homogeneous in the tested liver, and the controlling environment and methodology should be improved in the near future. The level of hepatic inflammation, as indicated by elevated interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α) levels, appears negligible under the current hyperthermia protocol. Conclusions: Two-stage microwave hyperthermia using magnetic nanoparticles is a promising therapeutic modality for liver cancer, with promising results from animal studies opening the way for further research in humans. Full article

Cationic arabinogalactan (AG) derivatives with a degree of substitution (0.02–0.19) containing quaternary ammonium groups were prepared by reaction of the etherification of (3-Chloro-2-hydroxypropyl)-trimethylammonium chloride (CHPTAC), catalyzed by an aqueous solution of sodium hydroxide. The effect of etherification was assessed by the degree of substitution (DS). The DS values of the AG samples were controlled by the varied pH of the reaction mixture from 10 to 12 and the duration of the process quaternization (2, 18, 24, 30 and 72 h). In comparison, the quaternized samples of the AG were characterized by physicochemical research methods, such as elemental analysis, gel permeation chromatography (GPC), Fourier Transform Infrared (FTIR), and ¹H nuclear magnetic resonance (NMR) spectroscopy, and thermogravimetric analysis (TGA). Furthermore, the improved antioxidant capacity of the quaternized AGs was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay. It was found that the most favorable conditions for the quaternization process were pH = 12, duration and temperature of the process of 31.6 h and 50 °C, respectively. The esterification reaction was accompanied by hydrolysis side reactions at a longer process. Full article

The recycling of a planar composite Pd membrane over a porous stainless-steel support modified with a CeO₂ interlayer (Pd/CeO₂/PSS) was investigated using a leaching-based recycling strategy to recover palladium while maintaining the support’s structural integrity. The membrane was prepared by a continuous flowing electroless pore-plating method (cf-ELP-PP) previously developed by our group. A series of experiments was conducted to evaluate the effect of leaching conditions—temperature, acid concentration, and duration—on Pd extraction and support preservation. Nitric acid (HNO₃) was used as the leaching agent, and the condition of 30 vol.% HNO₃ at 35 °C for 24 h was found to enable complete Pd recovery with limited dissolution of metals from the support. The regenerated supports exhibited an Fe-Cr oxide layer and part of the CeO₂ interface, allowing the elimination of cleaning and calcination steps in the membrane reprocessing workflow. A new Pd-CeO₂ interfacial layer was applied, followed by Pd redeposition via cf-ELP-PP. The resulting recycled membrane exhibited a homogeneous and defect-free Pd layer, with hydrogen permeation performance comparable to that of membranes fabricated on fresh supports. These results demonstrate that Pd membranes can be successfully fabricated on recycled 316L stainless-steel substrates, supporting the viability of this approach for material reuse in membrane technology. Full article

The lower melt strength of biodegradable materials in comparison to low density polyethylenes raises serious issues regarding their processability via blown film molding. Thus, reliable rheological characterization is a viable option for assessing their efficient flow performance. The blends of poly (lactic acid) (PLA) and poly (butylene adipate-co-terephthalate) (PBAT) modified with four chain-extending cross-linkers (CECLs) undergo shearing during extrusion and are subjected to extensional deformation during the subsequent film blowing. The shear viscosity data obtained with a capillary rheometer corresponded well to the molecular weights obtained by gel permeation chromatography, while an evaluation of elongational viscosity using a Sentmanat Extensional Rheometer failed due to sample sagging during the process of temperature setting and an unacceptable deviation from the theoretically supposed exponential decrease of sample cross-sections. Therefore, the response of the PBAT/PLA blends to elongation was determined via changes in the duration of time intervals corresponding to the rupture of elongated samples. An increased consistency of the PBAT/PLA blends with CECL, as previously indicated by dynamic mechanical analysis, differential scanning calorimetry, and scanning electron microscopy, was evaluated in this way. Full article

Bedaquiline is known to shorten the duration of therapy of tuberculosis but has limitations, e.g., poor solubility and adverse effects such as prolongation of the QT interval. In this study, bedaquiline was incorporated into an inherently targeted nanosystem for improved permeation of the drug, with ex vivo diffusion studies performed to investigate its penetration. The bedaquiline-loaded mannan–chitosan oligosaccharide lactate nanoparticles were prepared by a one-step ionic gelation probe sonication method. A PermeGear 7-in-line flow-through diffusion system was used for the ex vivo diffusion studies across porcine and human pericardia. Bedaquiline-loaded nanoparticles with a particle size and potential of 192.4 nm and 40.5 mV, respectively, were obtained. The drug-loaded mannan–chitosan nanoparticles had an encapsulation efficacy of 98.7% and drug loading of 0.6%. Diffusion data indicated a steady-state flux of 2.889 and 2.346 µg.cm⁻².min⁻¹ for porcine and human pericardia, respectively. The apparent permeability coefficients were calculated to be 2.66 × 10⁻⁴ cm.min⁻¹ and 2.16 × 10⁻⁴ cm.min⁻¹ for porcine and human pericardia, respectively. The lag phases were 52.72 min and 0 min for porcine and human pericardia, respectively. The drug permeation indicated a consistent and linear diffusion pattern across both porcine and human pericardia, additionally approving the porcine pericardium as a great comparable tissue to human tissue for pericardial studies. This study is the first to demonstrate ex vivo diffusion of bedaquiline-loaded, macrophage-targeted chitosan–mannan nanoparticles across both human and porcine pericardia, representing a novel platform for disease-targeted, localized treatment of TB pericarditis. Full article

To address the underutilization of Schizochytrium limacinum meal, polysaccharides from Schizochytrium limacinum meal (SLMPs) were prepared via ultrasonic-assisted eutectic-solvent-based extraction. Although polysaccharides exhibit promising application potential, the structural ambiguity of SLMPs necessitates systematic investigation to elucidate their structure–activity relationships, thereby providing a scientific foundation for their subsequent development and utilization. Using response-surface methodology (RSM), the optimized extraction conditions were determined as follows: ultrasonic temperature of 52 °C, ultrasonic duration of 31 min, ultrasonic power of 57 W, water content of 29%, and a material-to-liquid ratio of 1:36 g/mL. Under these conditions, the maximum polysaccharide yield reached 9.25%, demonstrating a significant advantage over the conventional water extraction method (4.18% yield). Following purification, the antioxidant activity and structural characteristics of SLMPs were analyzed. The molecular weight, monosaccharide composition, reducing groups, and higher-order conformation were systematically correlated with antioxidant activity. Fourier-transform infrared spectroscopy (FTIR), monosaccharide composition analysis, and ¹H nuclear magnetic resonance (NMR) spectroscopy revealed characteristic polysaccharide functional groups (C–O, O–H, and C=O). Monosaccharides such as glucose (Glc), galactose (Gal), and arabinose (Ara) were found to enhance antioxidant activity. High-performance gel permeation chromatography (HPGPC) indicated a molecular weight of 20.7 kDa for SLMPs, with low-molecular-weight fractions exhibiting superior antioxidant activity. Scanning electron microscopy (SEM) further demonstrated that ultrasonically extracted polysaccharides possess porous structures capable of chelating redox-active functional groups. These findings suggest that ultrasonic-assisted eutectic-solvent-based extraction is an efficient method for polysaccharide extraction while preserving antioxidant properties. Full article

Imipramine hydrochloride (IMP), a tricyclic antidepressant used for major depression, enuresis, and neuropathic pain, is limited by gastrointestinal complications, low oral bioavailability (44%), and complex dosing requirements. This study aimed to explore a novel non-invasive nasal delivery system using chitosan nanoparticles (Cs NPs) embedded in an in situ gel to address the limitations of oral IMP administration. Cs NPs loaded with IMP were synthesized via ionic gelation and assessed for precision in drug concentration using a validated HPLC method. The particles were integrated into a thermoresponsive polymer, Pluronic F127, to form an in situ gel suitable for nasal administration. The formulation was characterized for gelation temperature, duration, viscosity, mucoadhesive strength, and overall gel robustness. Drug release kinetics and the controlled release mechanism were studied using ex vivo permeation tests with Franz diffusion cells and nasal sheep mucosa. The optimized nanoparticle formulation (F4-50) exhibited a consistent PS of 141.7 ± 2.2 nm, a zeta potential (ZP) of 16.79 ± 2.1 mV, and a high encapsulation efficiency of 67.71 ± 1.9%. The selected in situ gel formulation, F4-50-P1, demonstrated a gelation temperature of 33.6 ± 0.94 °C and a rapid gelation time of 48.1 ± 0.7 s. Transform-attenuated total reflectance infrared spectroscopy (ATR-IR) confirmed the compatibility and effective encapsulation of IMP within the formulation. The release profile of F4-50 included an initial burst release followed by a sustained release phase, with F4-50-P1 showing improved control over the burst release. The flux rates were 0.50 ± 0.01 mg/cm²/h for F4-50 and 0.33 ± 0.06 mg/cm²/h for F4-50-P1, indicating effective permeation. The developed chitosan nanoparticle-based in situ gel formulation provides a promising approach for the controlled release of IMP, enhancing therapeutic efficacy and patient compliance while mitigating the disadvantages associated with oral delivery. Full article

In the framework of a circular economy, wastewater treatment should be oriented toward processes that allow the recovery of the resources present in the wastewater while ensuring good effluent quality. Nitrogen recovery is usually carried out in streams concentrated in this nutrient because these high concentrations facilitate nitrogen valorization. On the other hand, the mainstream of a wastewater treatment plant (WWTP) has a high potential for nitrogen recovery, but it is not usually considered because it is hard to manage due to its low nitrogen concentration. To solve this problem and facilitate the recovery of nitrogen in the mainstream, this work proposes ion exchange with zeolites as a stage of ammonium concentration, to provide a nitrogen-concentrated stream that could be valorized by another technology, while obtaining a nitrogen-free effluent. The working stream, the permeate of an AnMBR process in the mainstream, has suitable characteristics to be treated in an ion exchange column (free of suspended solids and with very low organic matter content). To this end, the effect of the working flow rate (17.5 to 4.4 BV/h) and the ammonium concentration (54 to 17 mg NH₄-N/L) on the adsorption capacity of the zeolite in the loading phase was evaluated. The adsorption curves were fitted to three mathematical models: Thomas, Bohart–Adams, and Yoon–Nelson. The effect of the regeneration flow rate (from 8.7 to 2.2 BV/h) and the regenerant concentration (NaOH at 0.2, 0.1, and 0.05 M) on regeneration capacity and efficiency were also studied. A novel control strategy based on effluent conductivity was used in both phases to control the duration of the adsorption and regeneration phases. Full article

Timely and accurate detection of viruses is crucial for infection diagnosis and treatment. However, it remains a challenge to develop a portable device that meets the requirement of being portable, powerless, user-friendly, reusable, and low-cost. This work reports a compact ∅30 × 48 mm portable powerless isothermal amplification detection device (material cost ∼$1 USD) relying on LAMP (Loop-Mediated Isothermal Amplification). We have proposed chromatographic-strip-based microporous permeation technology which can precisely control the water flow rate to regulate the exothermic reaction. This powerless heating combined with phase-change materials can maintain a constant temperature between 50 and 70 °C for a duration of up to 49.8 min. Compared with the conventional methods, it avoids the use of an additional insulation layer for heat preservation, greatly reducing the size and cost. We have also deployed a color card and a corresponding algorithm to facilitate color recognition, data analysis, and storage using a mobile phone. The experimental results demonstrate that our device exhibits the same limit of detection (LOD) as the ProFlex PCR for SARS-CoV-2 pseudovirus samples, with that for both being ${10}^3$ copies/μL, verifying its effectiveness and reliability. This work offers a timely, low-cost, and easy way for respiratory infectious disease detection, which could provide support in curbing virus transmission and protecting the health of humans and animals, especially in remote mountainous areas without access to electricity or trained professionals. Full article

Lidocaine is the most commonly used local anesthetic worldwide, known for its rapid onset and moderate duration of anesthesia. However, it is short-lived and does not effectively promote effective topical anesthesia in the oral cavity when used alone. Our aim was to investigate whether an approximate 50% encapsulation of lidocaine in poly(ε-caprolactone) nanocapsules (LDC-Nano) would be able to increase its permeation and analgesic efficacy and reduce cytotoxicity. In this study, we characterized LDC-Nano and conducted MTT tests with HaCaT cells to assess their in vitro cytotoxicity. Additionally, in vitro permeation assays across the pig esophageal epithelium and the anesthetic efficacy of the hind paw incision model in rats were performed. Plain lidocaine (LDC) was compared with LDC-Nano and lidocaine hydrochloride plus epinephrine (LDC-Epi). The physicochemical characteristics of LDC-Nano were satisfactory (pH: 8.1 ± 0.21; polydispersity index: 0.08 ± 0.01; mean diameter (nm): 557.8 ± 22.7; and encapsulation efficiency (%): 51.8 ± 1.87) and remained stable for up to 4 months. LDC-Nano presented similar in vitro cytotoxicity to LDC but was higher than LDC-Epi (LD₅₀: LDC = 0.48%; LDC-Nano = 0.47%; and LDC-Epi = 0.58%; p < 0.0001). Encapsulation increased the permeability coefficient about 6.6 times and about 7.5 the steady-state flux of lidocaine across the mucosal epithelium. Both encapsulation and epinephrine improved anesthesia duration, with epinephrine demonstrating superior efficacy (100% of animals were anesthetized up to 100, 30, and 20 min when LDC-Epi, LDC-nano, and LDC were used, respectively). Although LDC-Epi demonstrated superior in vivo anesthetic efficacy, the in vitro permeation and cytotoxicity of LDC-Nano indicate promising avenues for future research, particularly in exploring its potential application as a topical anesthetic in the oral cavity. Full article