Search Results (217)

Prolonged drought and soil degradation severely affect soil fertility and limit crop productivity. Superabsorbent hydrogels offer an effective solution for improving water retention in soil and supporting plant growth. In this work, we examined the performance of superabsorbent hydrogels based on sodium alginate, acrylic acid (AA), and poly (ethylene oxide) (PEO) cross-linked with 12.5 kGy using e-beam irradiation. The hydrogels were assessed in various aqueous environments by examining network characteristics, swelling capacity, and swelling kinetics to evaluate the impact of water’s electrical conductivity (which ranges from 0.05 to 321 μS/cm). Morphological and chemical structure changes were evaluated using SEM and FTIR techniques. The results demonstrated that water conductivity significantly affected the physicochemical properties of the hydrogels. Swelling behavior showed notable sensitivity to electrical conductivity variations, with swelling degrees reaching 28,400% at 5 μS/cm and 14,000% at 321 μS/cm, following first-order and second-order kinetics. FTIR analysis confirmed that structural modifications correlated with water conductivity, particularly affecting the O–H, C–H, and COOH groups sensitive to the ionic environment. SEM characterization revealed a porous morphology with an interconnected microporous network that facilitates efficient water diffusion. These hydrogels show exceptional swelling capacity and are promising candidates for sustainable agriculture applications. Full article

Hydrogen-rich water (HRW) has shown neuroprotective effects in acute brain injury, but its role in chronic radiation-induced brain injury (RIBI) remains unclear. This study investigated the long-term efficacy of HRW in mitigating cognitive impairment and neuronal damage caused by chronic RIBI. Fifty male Sprague Dawley rats were randomly divided into five groups: control, irradiation (IR), IR with memantine, IR with HRW, and IR with combined treatment. All but the control group received 20 Gy whole-brain X-ray irradiation, followed by daily interventions for 60 days. Behavioral assessments, histopathological analyses, oxidative stress measurements, ¹⁸F-FDG PET/CT imaging, transcriptomic sequencing, RT-qPCR, Western blot, and serum ELISA were performed. HRW significantly improved anxiety-like behavior, memory, and learning performance compared to the IR group. Histological results revealed that HRW reduced neuronal swelling, degeneration, and loss and enhanced dendritic spine density and neurogenesis. PET/CT imaging showed increased hippocampal glucose uptake in the IR group, which was alleviated by HRW treatment. Transcriptomic and molecular analyses indicated that HRW modulated key genes and proteins, including CD44, CD74, SPP1, and Wnt1, potentially through the MIF, Wnt, and SPP1 signaling pathways. Serum CD44 levels were also lower in treated rats, suggesting its potential as a biomarker for chronic RIBI. These findings demonstrate that HRW can alleviate chronic RIBI by preserving neuronal structure, reducing inflammation, and enhancing neuroplasticity, supporting its potential as a therapeutic strategy for radiation-induced cognitive impairment. Full article

This paper proposes a novel control strategy for a dual-stage grid-connected solar photovoltaic (PV) system designed to ensure reliable and efficient operation under unstable grid conditions. The strategy incorporates a Phase-Locked Loop (PLL)-based positive sequence estimator for accurate detection of grid voltage disturbances, including sags, swells, and fluctuations in solar irradiance. A dynamic DC-link voltage regulation mechanism is employed to minimize converter power losses and enhance the performance of the Voltage Source Converter (VSC) under weak grid scenarios. The control scheme maintains continuous maximum power point tracking (MPPT) and unity power factor (UPF) operation, thereby improving overall grid power quality. The proposed method is validated through comprehensive simulations and real-time hardware implementation using the OPAL-RT OP4510 platform. The results demonstrate compliance with IEEE Standard 519, confirming the effectiveness and robustness of the proposed strategy. Full article

Dual Maximum Power Point Tracking (MPPT) inverters are essential in residential and small commercial solar power systems, optimizing power extraction from two independent solar panel arrays to enhance efficiency and energy harvesting. On the other hand, the Three-Level T-Type Voltage Source Inverter (3L T-Type VSI) is known for its reduced switching losses, improved harmonic distortion, and reduced part count in comparison to other three-level topologies. In this paper, a novel architecture is proposed to integrate the dual MPPT structure directly to each DC-side split capacitor of the 3L T-Type VSI, taking advantage of the intrinsic characteristics of the inverter’s topology. Further performance enhancement is achieved by integrating a classical MPPT strategy to the control framework to make it feasible for a real-case grid integration. The combination of these methods ensures faster and stable tracking under dynamic irradiance conditions. Considering that strategies dedicated to balancing the DC-link capacitor’s voltage slightly affect the AC-side current waveform, an enhanced sliding mode control (SMC) strategy tailored for dual MPPT and 3L T-Type VSI is deployed, combining the simplicity of conventional PI controllers used in the independent MPPT-based DC-DC converters with the superior robustness and dynamic performance of SMC. Real-time results obtained using the OPAL-RT Hardware-in-the-Loop platform validated the performance of the proposed control strategy under realistic test scenarios. The current THD was maintained below 4.8% even under highly distorted grid conditions, and the controller achieved a steady state within approximately 15 ms following perturbations in the DC-link voltage, sudden irradiance variations, and voltage sags and swells. Additionally, the power factor remained unitary, enhancing power transfer from the renewable source to the grid. The proposed system was able to achieve efficient power extraction while maintaining high power quality (PQ) standards for the output, positioning it as a practical and flexible solution for advanced solar PV systems. Full article

Excessive exposure to ultraviolet B (UVB) radiation can lead to skin damage, such as erythema and swelling. Echinacoside is a key effective ingredient of medicinal plant Cistanche deserticola commonly used for therapies and treatments for anti-aging and irradiation-related skin diseases. However, the molecular mechanism underlying the action of echinacoside remains unclear. Here, we report that echinacoside ameliorates UVB-induced skin damage by directly acting on the Ca²⁺-permeable and thermosensitive transient receptor potential vanilloid 3 (TRPV3) channel. Topical application of echinacoside efficaciously suppresses skin lesions induced by UVB radiation in wild-type mice but has no additional benefit in Trpv3 knockout mice. In whole-cell patch clamp recordings, echinacoside selectively inhibits TRPV3 channel currents induced by 2-aminoethoxydiphenyl borate in a concentration-dependent manner with an IC₅₀ value of 21.94 ± 1.28 μM. The single-channel patch clamp results show that echinacoside significantly reduces the open probability and open frequency without significantly altering TRPV3 channel unitary conductance. Molecular docking and site-specific mutagenesis indicate that residue T636 on the p-loop and residue T665 on the S6 segment of TRPV3 are critical for echinacoside binding to TRPV3. Taken together, our findings provide a molecular basis for further studies as use of natural echinacoside in irradiation-related skin care therapy, thus establishing a significant role of the TRPV3 channel in acute skin injury. Full article

This study concerns the effects of the addition of crystalline nanocellulose (CNC) and ionizing radiation on the properties of cornstarch–poly(vinyl alcohol) (PVA) films. Moreover, ESR spectroscopy and gas chromatography were used for a comparison of the reactivity of CNC and two micro-sized celluloses (microfibrinal (MFC) and microcrystalline (MCC)) under the influence of irradiation. This showed that the highest reactivity of CNC was related to the lowest sizes of the particles (observed by SEM). A series of starch/PVA/CNC films characterized by a starch/PVA ratio equal to 40:60 and a CNC addition in a range from 0.5 wt% to 10.0 wt% with 30 wt% of glycerol were prepared by solution casting. The films were irradiated in a gamma chamber (in a vacuum) or in an e-beam (in the air) using a dose of 25 kGy. The mechanical properties, contact angle to water, swelling and solubility in water, moisture absorption in a humid atmosphere, and the gel content of the films were determined. The functional properties of the films strongly depended on the addition of CNC. The films formed with 1.0 wt% of CNC had the best mechanical properties and the lowest surface and bulk hydrophilicity, which could be improved further after irradiation. The results can be related to the increased homogeneity and modified distribution of the nanoparticles in the films after irradiation (as shown by SEM). Degradation is a predominant process that occurs due to irradiation; however, the crosslinking processes also have some role. The protective effect of CNC against degradation was discovered by diffuse reflectance spectroscopy. Full article

Global challenges in agriculture, in terms of water and nutrient loss control, require new approaches to maintaining or even increasing crop production. Promising materials, such as superabsorbent hydrogels of hybrid types obtained from natural polymers grafted with synthetic polymers, represent a viable solution to solve these problems and maintain a clean environment. In view of this, two types of hydrogels based on sodium alginate, acrylic acid and polyethylene oxide obtained using 5.5 MeV electron-beam irradiation were subjected to degradation through burial in the soil. Swollen hydrogels in two types of water (distilled and tap) and two types of nutrient solutions (synthetic nutrient solution and 100% natural organic nutrient solution), with different pHs of 5.40, 6.05, 7.45 and 7.66, were buried in soil for 30 and 60 days and then extracted and analyzed in terms of their mass loss, swelling behavior and cross-linking structure. The highest mass losses after both 30 and 60 days were recorded for the hydrogels buried in soils whose humidity was maintained by watering them with the basic solutions (tap water and the organic nutrient solution). Structural modifications associated with the degradation process were highlighted by decreases in the cross-link densities and increases in the mesh sizes and swelling. These results were confirmed using FTIR and SEM techniques. Full article

With the development of semiconductor technology, the increasing number of power electronic converters and nonlinear loads has further exacerbated power-quality issues in the grid. To address this, this paper presents an improved DC-side voltage control strategy for UPQC, aiming to enhance power quality under complex conditions. First, an adaptive filter is integrated into the linear active disturbance rejection control (LADRC) to address control accuracy issues caused by noise and parameter variations. To solve the voltage sag problem resulting from the filter, the effects of fixed-step and various variable-step algorithms within the filter are analyzed, and the optimal control strategy is identified. Simulation results demonstrate that the proposed arctangent function-based variable step-size algorithm (VAV-LADRC) strategy effectively improves the UPQC system’s performance in mitigating voltage sags, swells, and harmonics under dynamic load changes, enhancing the stability of the DC-side voltage. To further validate the generalizability of the method, a co-simulation of a photovoltaic power-generation system with the UPQC is conducted, simulating variations in solar irradiance. The results show that the proposed method maintains excellent control performance under complex conditions, providing a better practical solution for the efficient use of green energy. Full article

Wound healing is a complex process involving stages such as hemostasis, inflammation, proliferation, and remodeling. In this context, polymers are useful materials for wound treatment. This research used the Casting method to prepare films from 2% polyvinylpyrrolidone (PVP) gels. Subsequently, PVP films were grafted with maleic acid (MA) (PVP-g-PAM) to load naringin (NA) and silver nanoparticles (AgNPs) in order to obtain a material with pH responsiveness and antibacterial properties. The modified PVP-g-PAM films were prepared using gamma-ray irradiation through a pre-irradiation oxidative method at a dose rate of 13.7 kGy h⁻¹, doses ranging from 10 to 25 kGy, and reaction times from 50 to 80 min in a bath of water, all samples at 50 °C, and a fixed monomer concentration of 15% (w/v) MA in THF. The conditions that yielded the highest percentage of grafting were 20 kGy and 60 min. NA was loaded at a fixed concentration of 5%. Data release showed that the films follow the Korsmeyer-Peppas kinetic model. Synthesis of AgNPs was performed by γ-ray irradiation–reduction (10 and 30 kGy), using PVP as a stabilizer. AgNPs showed in vitro effectiveness against E. coli and S. aureus. Films were characterized by FTIR-ATR, TGA, DSC, mechanical properties, swelling index, and contact angle. Further studies must be implemented; however, the results up now suggest that PVP-g-PAM loaded with NA and AgNPs can be useful as a potential wound dressing. Full article

This study presents the synthesis of allyl-functionalized polysaccharide carbamates (AFCs) with tailored water solubility designed for use in responsive hydrogels and 3D printing applications. A modular one-pot approach was employed to produce cellulose- and xylan-based AFCs, utilizing polysaccharide phenyl carbonates as activated compounds. By fine-tuning the degree of substitution (DS) of functional groups, the water solubility and shear-thinning properties of AFCs were controlled to enhance the gelation and printability. AFC-based hydrogels could be obtained by rapid gelation induced without harmful catalysts through UV irradiation at 365 nm. The materials displayed highly porous and interconnected microstructures, as well as mechanical resilience and high swelling ratios. The hydrogel formation was characterized, and its crosslinking degree was calculated using HR-MAS NMR. The study demonstrated that gelation behavior was sensitive to the pH value, with optimal results under neutral or acidic conditions. Initial 3D printing trials confirmed the material’s rapid shaping capabilities, which is beneficial for biomedical applications and advanced manufacturing of stimuli-responsive materials. Full article

Daytime radiative cooling, based on selective infrared emissions through atmospheric transparency windows to outer space and the reflection of solar irradiance, is a zero-energy and environmentally friendly cooling technology. Poly(ethylene oxide) (PEO) electrospun membranes have both selective mid-infrared emissions and effective sunlight reflection, inducing excellent daytime radiative cooling performance. However, PEO is highly water soluble, which makes electrospun PEO membranes unable to cope with rainy conditions when used for outdoor daytime radiative cooling. Herein, we report an in situ UV-crosslinking strategy for preparing PEO electrospun membranes with water resistance for the application of daytime radiative cooling. Acrylate-terminated PEO was synthesized and mixed together with cross-linking agents and photoinitiators to prepare the electrospinning solution. During electrospinning, the nanofibers were irradiated with UV light to initiate the cross-linking. For a membrane with a thickness of 200 μm, the average solar reflectance was 89.6%, and the infrared emissivity (8–13 μm) was 96.3%. Although slight swelling happens to the cross-linked membrane once it comes into contact with water, the fibrous morphology shows no obvious change when prolonging the water soaking time, indicating excellent water resistance. The outdoor cooling performance test results showed that compared to the average temperature of the air in the test box, the average temperature drop in the membrane before and after water soaking was 13.8 °C and 11.5 °C, respectively. Crosslinked PEO-based electrospun membranes with both water resistance and radiative cooling performance may have real applications for outdoor daytime radiative cooling. Full article

Biomaterials (films, foils, fibers, coatings) based on proteins are becoming increasingly important due to the growing applications for which pork and beef gelatins are used. Alternative types of gelatins (poultry or fish), which have not yet been sufficiently tested, represent a high potential. This study looks at the effect of different UV exposure times on chicken gelatin films with added glycerol. The gelatin was prepared using a unique enzymatic hydrolysis process. The quality of the UV-exposed films was compared with gelatin films not exposed to UV light. Radiation-induced crosslinking improved the mechanical and physical properties of the films. The UV crosslinked films are stabilized at a degree of swelling from 700 to 900%; moreover, they extend their dissolution to more than 7 days while maintaining their original shape. In contrast, non-crosslinked films swell and dissolve in water faster. Further, the effect of UV radiation on the water vapor permeability and color of the films was monitored. Water vapor permeability decreased by 2.5 times with increasing crosslinking time for 30% and 40% glycerol content, and the yellowness of the irradiated samples increased with exposure time in the interval from 24 to 28. Using Fourier transform infrared spectroscopy, the differences in the amount of bonding based on irradiation time were analyzed. As a result of crosslinking, the intensity of existing bonds increased. Thermal properties were verified through differential scanning calorimetry and thermogravimetric analysis. The results proved that chicken gelatin is suitable for preparing films in foods and medicine. Applying UV radiation to crosslink gelatin films is an alternative to traditionally used chemical crosslinkers. Full article

Hydrogel nanocomposites that respond to external stimuli and possess switchable electrical properties are considered as emerging materials with potential uses in electrical, electrochemical, and biological devices. This work reports the synthesis and characterization of thermo-responsive and electroconductive hydrogel nanocomposites based on poly(N-isopropylacrylamide) (PNiPAAm) and gold nanoparticles (nanospheres—AuNPs and nanorods—AuNRs) using two different synthetic techniques. Method I involved γ-irradiation-induced crosslinking of a polymer matrix (hydrogel), followed by radiolytic in situ formation of gold nanoparticles, while Method II included the chemical synthesis of nanoparticles, followed by radiolytic formation of a polymer matrix around the gold nanoparticles. UV–Vis spectral studies revealed the presence of local surface plasmon resonance (LSPR) bands characteristic of nanoparticles of different shapes, confirming their formation and stability inside the polymer matrix. Morphological, structural, and physicochemical analyses indicated the existence of a stable porous polymer matrix, the formation of nanoparticles with a face-centered cubic structure, increased swelling capacity, and a slightly higher volume phase transition temperature (VPTT) for the hydrogel nanocomposites. Comparative electrochemical impedance spectroscopy (EIS) showed an increase in conductivity for the nano Au-PNiPAAm hydrogel nanocomposites compared to the PNiPAAm hydrogel, with a considerable rise detected above the VPTT. By reverting to room temperature, the conductivity decreased, indicating that the investigated hydrogel nanocomposites exhibited a remarkable reversible “on–off” thermo-switchable mechanism. The highest conductivity was observed for the sample with rod-shaped gold nanoparticles. The research findings, which include optical, structural, morphological, and physicochemical characterization, evaluation of the efficiency of the chosen synthesis methods, and conductivity testing, provide a starting point for future research on the given nanocomposite materials with integrated multifunctionality. Full article

Potato starch is widely utilized in the food industry. Gamma irradiation is a cost-effective and environmentally friendly method for starch modification. Nevertheless, there is a scarcity of comprehensive and consistent knowledge regarding the physicochemical characteristics of high-dose gamma-irradiated potato starch, retrogradation properties in particular. In this study, potato starch was exposed to gamma rays at doses of 0, 30, 60, 90, and 120 kGy. Various physicochemical properties, including retrogradation characteristics, were investigated. Generally, the apparent amylose content (AAC), water absorption, gel viscosity, gel hardness, and gumminess decreased as the doses of gamma irradiation increased. Conversely, the resistant starch (RS), amylose content evaluated by the concanavalin A precipitation method, water solubility, and enthalpy of gelatinization were increased. Additionally, swelling power, crystalline structure, and amylopectin branch chain length distribution either remained stable or exhibited only minor changes. Notably, the degree of retrogradation of potato starches on day 7 was positively correlated with the doses of gamma irradiation. Full article

Today, hydrogel dressings that can protect injury sites and effectively promote healing have become highly desirable in wound management. Therefore, multifunctional silver-poli(N-isopropylacrylamide/itaconic acid) (Ag-P(NiPAAm/IA)) hydrogel nanocomposites were developed for potential application as topical treatment dressings. The radiolytic method, used for the crosslinking of the polymer matrix as well as for the in situ incorporation of silver nanoparticles (AgNPs) into the polymer matrix, enables the preparation of hydrogel nanocomposites without introducing harmful and toxic agents. Moreover, materials produced using γ-irradiation are simultaneously sterilized, thus fulfilling one of the basic requirements regarding their potential biomedical applications. The NiPAAm/IA ratio and the presence of AgNPs influenced the microstructural parameters of the investigated systems. Increasing the IA content leads to the formation of a more porous polymer matrix with larger pores, while the incorporated AgNPs act as additional junction points, decreasing the porosity and pore size of the resulting nanocomposite hydrogels. Swelling studies showed that most investigated systems uptake the fluids from their surroundings by non-Fick diffusion. Further, the Ag⁺ ion release, antibacterial activity, and cytotoxicity of Ag-P(NiPAAm/IA) hydrogel nanocomposites were examined to evaluate their biomedical potential. All hydrogel nanocomposites showed an initial burst release of Ag⁺ ions (useful in preventing bacteria adherence and biofilm formation), followed by a slower release of the same (ensuring sterility for longer use). An antibacterial activity test against Escherichia coli and Staphylococcus aureus showed that Ag-P(NiPAAm/IA) hydrogel nanocomposites, with silver concentrations around 10 ± 1 ppm, successfully prevent bacterial growth. Finally, it was shown that the investigated hydrogel nanocomposites do not exhibit a cytotoxic effect on human keratinocyte HaCaT cells. Therefore, these multifunctional hydrogel nanocomposites may promote wound repair and show promising potential for application as functional wound dressing. Full article