Search Results (99)

Leishmaniasis is an infectious disease common in tropical and subtropical regions worldwide. This study aimed to develop a topical meglumine antimoniate gel (MA-gel) for the treatment of cutaneous leishmaniasis. The MA-gel was characterized in terms of morphology, pH, swelling, porosity, rheology, and thermal properties by differential scanning calorimetry (DSC). Biopharmaceutical evaluation included in vitro drug release and ex vivo skin permeation. Safety was evaluated through biomechanical skin property measurements and cytotoxicity in HaCaT and RAW 267 cells. Leishmanicidal activity was tested against promastigotes and amastigotes of Leishmania infantum, and in silico studies were conducted to explore possible mechanisms of action. The composition of the MA-gel included 30% MA, 20% Pluronic^® F127 (P407), and 50% water. Scanning electron microscopy revealed a sponge-like and porous internal structure of the MA-gel. This formula exhibited a pH of 5.45, swelling at approximately 12 min, and a porosity of 85.07%. The DSC showed that there was no incompatibility between MA and P407. Drug release followed a first-order kinetic profile, with 22.11 µg/g/cm² of the drug retained in the skin and no permeation into the receptor compartment. The MA-gel showed no microbial growth, no cytotoxicity in keratinocytes, and no skin damage. The IC₅₀ for promastigotes and amastigotes of L. infantum were 3.56 and 23.11 µg/mL, respectively. In silico studies suggested that MA could act on three potential therapeutic targets according to its binding mode. The MA-gel demonstrated promising physicochemical, safety, and antiparasitic properties, supporting its potential as a topical treatment for cutaneous leishmaniasis. Full article

A passive time reversal method with a metamodel (PTR-MM) is proposed to improve underwater source localization under ocean conditions. PTR-MM eliminates model mismatch errors by replacing the conventional sound propagation model with a Kriging metamodel. This metamodel is optimally constructed based on measured sound field data. The method combines a metamodel with a passive time reversal (PTR) process to generate a focused sound field whose intensity peaks correspond to source positions. In numerical simulations using the KRAKEN model in a range-independent waveguide, PTR-MM accurately localizes single and multiple sources, is insensitive to mismatches in key environmental parameters, and maintains unbiased performance down to −20 dB signal-to-noise ratios (SNRs). Experimental validation on the SWellEx-96 Event S5 dataset confirms that PTR-MM outperforms conventional PTR in both single- and dual-source localizations, achieving most mean absolute percentage errors (MAPEs) below 10% when trained and tested in consistent environments. Further studies reveal that localization accuracy depends primarily on signal quality, array aperture, and element spacing, rather than on source frequency. However, PTR-MM performance degrades if the metamodel is trained in an environment that differs from the test conditions. The above findings demonstrate the potential of combining PTR with a metamodel for robust and real-time localization. Full article

Under wideband interference conditions, traditional neural networks often suffer from low accuracy in single-frequency direction-of-arrival (DOA) estimation and face challenges in detecting single-frequency sound sources. To address this limitation, we propose a novel model called Parallel Net. The architecture adopts a frequency-parallel design: it first employs a recurrent neural network, the generalized feedback gated recurrent unit (GFGRU), to independently extract features from each frequency component, and then it fuses these features through an attention mechanism. This design significantly enhances the network’s capability in estimating the DOA of single-frequency signals. The simulation results demonstrate that when the signal-to-noise ratio (SNR) exceeds −10 dB, Parallel Net achieves a mean absolute error (MAE) below 2°, outperforming traditional frequency-coherent neural networks and the MUSIC algorithm, and reduces the error to half that of classical beamforming (CBF). Further validation on the SWellEx-96 experiment confirms the model’s effectiveness in detecting single-frequency sources under wideband interference. Parallel Net exhibits superior sidelobe suppression and fewer spurious peaks compared to CBF, achieves higher accuracy than MUSIC, and produces smoother and more continuous DOA trajectories than conventional neural network models. Full article

Background: Moringa oleifera is one of the most famous plants used for medicinal purposes. Its leaf extracts have antimicrobial activity and antioxidant activities, and reduce swelling in ulcers. Objectives: The present article aimed to determine the metabolic profile of Moringa oleifera leaf extracts from two samples originating from India and to evaluate in vitro and ex vivo their biological activities. Methods: The antioxidant properties of Moringa oleifera leaf extracts (methanol, 50% ethanol, and 70% ethanol) were studied in vitro for antimicrobial, anti-inflammatory, and antioxidant activities. The ex vivo contractile effects of the extracts were determined by assaying circularly isolated smooth muscle (SM) strips from a rat’s stomach. Results: The obtained results indicated that one of the samples had amino acid and organic acid content approximately twice that of the second sample. In all the tests, the 50% ethanol extract of both samples showed better antioxidant activity (209 mM TE 100 g⁻¹ for the DPPH method). The 70% ethanolic extract of Sample 1 exhibited the strongest antimicrobial activity, inhibiting Gram-positive Bacillus cereus, Bacillus subtilis, and Staphylococcus aureus. The 50% ethanolic extract of both samples exhibited the highest anti-inflammatory activity, demonstrating a twice better effect than the reference drug diclofenac. Finally, the pre-incubation of SM preparations with both samples significantly enhanced the ACh-induced contractile response, increasing it by 134% and 111%, respectively. Conclusions: The findings suggested potential applications of Moringa oleifera as a suitable candidate for antimicrobial, antioxidant, anti-inflammatory, and antispasmodic supplementation for alternative pharmaceutical and nutraceutical products. Full article

Cell culture in two dimensions has been the main instrument in cellular and molecular biology. But there are limitations to two-dimensional culture when it comes to tissue engineering and in vivo reproduction. Tissue engineering technology enabled the creation of biomedical scaffolds, which are mostly utilized to biofabricate different artificial human organs. Tissue architecture that encourage cell proliferation can be produced using direct bioprinting technology. The development of bioinks for 3D bioprinting is consistently seen as a problem in the domains of biofabrication and tissue engineering. This study aimed to determine if Fibroblasts and Keratinocytes could grow on hydrogel scaffolds as efficiently as they can in the culture plates. Melanocytes were co-cultured, and the production of melanin was assessed in a two- and three-dimensional culture system. Scaffolds were fabricated using 8% alginate and 6% gelatin and 3D-printed using a cell link printer. FTIR was used to determine the precise composition of the gels. SEM analysis was performed for the cells present in gel and the topology of the cells. In addition, 8% alginate and 6% alginate gel scaffolds were analyzed for swelling and degradation over time in the cell growth medium and PBS. Furthermore, a gene expression study of cell cultures on scaffolds was performed through qPCR. A live/dead assay was performed to determine cell viability for cells grown on scaffolds for 7, 14, and 21 days. Most of the cells were shown to be viable, similar to the control cells grown on a plate. The findings from the SEM showed that cells were grown on the gel surface, remained viable even after 21 days, and displayed circular cells stacked three-dimensionally on the gel surface in the 3D scaffold. The MTT assay was performed to check the viability of cells cultured on a 3D-printed scaffold for 1, 5, and 15 days. We observed about 40% viable cells after 15 days, as shown by the MTT assay. Furthermore, a co-culture study with Melanocyte showed an increased production of melanin in a 3D culture as compared to a 2D culture. Our findings suggest that an alginate and gelatin polymer can be used as a cellular matrix for epithelial cell culture. Further, in vivo and ex vivo experiments are needed to validate the results for future applications in tissue engineering for wound healing and other tissue engineering domains. Full article

Kaempferol liposome hydrogel is a novel drug carrier designed to solve the problems of the poor water solubility and low bioavailability of kaempferol. By combining kaempferol with liposomes and further forming a hydrogel, this composite formulation not only improves the stability of the drug but also enhances its penetration and therapeutic effect on the skin. It was demonstrated that the liposomal hydrogel of kaempferol had ex vivo and in vivo antioxidant activities, which could effectively inhibit the inflammatory response and oxidative stress and, thus, showed significant efficacy in the treatment of acute eczema. In the acute eczema model, kaempferol liposome hydrogel significantly improved the skin condition of mice by reducing the symptoms of skin redness, swelling, and itching. The experimental results showed that the hydrogel was rapidly absorbed into the skin after application and continued to release the drug to maintain its efficacy for a longer period of time. In addition, the kaempferol liposome hydrogel also showed good physicochemical stability and was not easily discolored or separated, making it suitable for long-term use. As an innovative drug carrier for the treatment of acute eczema, the kaempferol liposome hydrogel shows good application prospects and provides a new treatment option for eczema patients. Full article

This study evaluates the chemical, physical, mechanical, and biological properties of untreated and heat-treated Cryptomeria japonica (Thunb ex L.f.) D.Don wood from the Azores, Portugal. Heat treatment was performed at 212 °C for 2 h following the Thermo-D class protocol. Chemical analysis revealed an increase in ethanol soluble extractives and lignin content after heat treatment, attributed to hemicellulose degradation and condensation reactions. Dimensional stability improved significantly, as indicated by reduced swelling coefficients and higher anti-swelling efficiency (ASE), particularly in the tangential direction. Heat-treated wood demonstrated reduced water absorption and swelling, enhancing its suitability for applications requiring dimensional stability. Mechanical tests showed a decrease in bending strength by 19.6% but an increase in the modulus of elasticity (MOE) by 49%, reflecting changes in the wood’s structural integrity. Surface analysis revealed significant color changes, with darkening, reddening, and yellowing, aligning with trends observed in other heat-treated woods. Biological durability tests indicated that both untreated and treated samples were susceptible to subterranean termite attack, although heat-treated wood exhibited a higher termite mortality rate, suggesting potential long-term advantages. This study highlights the impact of heat treatment on Cryptomeria japonica wood, emphasizing its potential for enhanced stability and durability in various applications. Full article

Researchers have been investigating the physical and morphological properties of biodegradable polymer and copolymer films, blending them with other chemicals to solve challenges in medical, industrial, and eco-environmental fields. The present study introduces a novel, straightforward method for preparing biodegradable hydrogels based on polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) for medical applications. The resulting PVA/PVP-based hydrogel uniquely combines the water absorbency, biocompatibility, and biodegradability of the polymer composite. For hygiene products and medical uses, such as wound healing, hydrogen peroxide (HP) was encapsulated in the PVA/PVP hydrogels for controlled release application. Incorporating PVP into PVA significantly enhances the hydrogel water absorbency and improves the mechanical properties. However, to mitigate the disadvantage of high water absorbency which could result in undesired early dissolution, efforts were made to increase the water resistance and the mechanical characteristics of these hydrogels using freeze–thaw (F/T) cycles and chemical crosslinking PVA chains with trisodium trimetaphosphate (STMP). The resulting hydrogels serve as environmentally friendly bio-based polymer blends, broadening their applications in medical and industrial products. The structural and morphological properties of the hydrogel were characterized using Fourier transform infrared spectroscopy (FTIR), environmental scanning electron microscope analysis (E-SEM), and water-swelling tests. The HP controlled release rate was evaluated through kinetic release experiments using the ex vivo skin model. The antibacterial activity of the hydrogel films was examined on four medically relevant bacteria: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa, with an adapted disk diffusion assay. Using this assay, we also evaluated the antibacterial effect of the hydrogel films over the course of days, demonstrating the HP controlled release from these hydrogels. These findings support further in vivo investigation into controlled HP release systems for improved wound-healing outcomes. Full article

Conventional matched-field processing (MFP) for acoustic source localization is sensitive to environmental mismatches because it is based on the wave propagation model and environmental information that is uncertain in reality. In this paper, a mode-predictable sparse Bayesian learning (MPR-SBL) method is proposed to increase robustness in the presence of environmental uncertainty. The estimator maximizes the marginalized probability density function (PDF) of the received data at the sensors, utilizing the Bayesian rule and two hyperparameters (the source powers and the noise variance). The replica vectors in the estimator are reconstructed with the predictable modes from the decomposition of the pressure in the representation of the acoustic normal mode. The performance of this approach is evaluated and compared with the Bartlett processor and original sparse Bayesian learning, both in simulation and using the SWellEx-96 Event S5 dataset. The results illustrate that the proposed MPR-SBL method exhibits better performance in the two-source scenario, especially for the weaker source. Full article

Artemisia vestita Wall. ex Besser, a traditional medicinal plant with healing properties, is receiving significant attention as a potential therapeutic agent for wound healing. In this study, eight Artemisia vestita leaf extract hydrogel formulations (F1–F8) were carefully designed and studied. The hydrogel formulations contained A. vestita leaf extract, tragacanth gum, humectants, preservatives, pH stabilizers, and Milli-Q water. A preformulation study was conducted to ensure safety and efficacy. Moreover, various experiments assessed the potential application and characteristics of A. vestita leaf extract hydrogel (ALEH). Drug release and swelling studies were conducted at different pH levels and temperatures. The best drug release model was identified based on the regression coefficient (R²). Antimicrobial efficacy was assessed using the agar well diffusion method, and wound healing in HaCat cells was assessed using the scratch assay. ALEH exhibited non-Fickian diffusion, with higher drug release noted at pH 6.8 than at pH 4.5, indicating pH-responsive behavior. It exhibited significant antimicrobial activity against various strains and achieved 95% wound closure after 24 h in vitro, indicating strong wound healing properties. It also had a long shelf life; therefore, it could have pharmaceutical and medical applications. Our study is the first to report the potential applications of ALEH in skincare and wound management. Full article

Recently proposed direct position determination (DPD) methods have garnered considerable interest in passive localization due to their excellent positioning accuracy. However, in multiple-target environments, error locations generated by wrong associations between different targets and arrays, called ghosts, may lead to incorrect estimations of the targets, reducing positioning accuracy. To address this, we propose a ghost discrimination method for broadband DPD that exploits the frequency structure differences between various targets. In the frequency coloring strategy proposed in this study, different RGB values are assigned to the spatial spectrum of different frequencies. Then, an RGB color spatial spectrum reflecting the different frequency structures of the signals is formed, which effectively distinguishes between real targets and ghosts visually and enhances multi-target localization accuracy. The probability of correctly distinguishing between targets and ghosts in the proposed method is evaluated using simulation results. It can effectively distinguish multiple targets even at a low SNR level, a significant improvement compared with the original DPD. Furthermore, the SwellEx-96 shallow-water experimental data set is utilized to demonstrate the effectiveness of the proposed method. Full article

To solve the poor performance or even failure of the cross-spectrum (CS) method in hydroacoustic weak-target passive velocimetry, a sparse Bayesian learning cross-spectrum method (SBL-CS), combining phase compensation with sparse Bayesian learning (SBL) is proposed in this paper. Firstly, the cross-correlation sound intensity is taken as the observation quantity and compensates for each frequency point of the cross-spectrum, which enables the alignment of cross-spectrum results at different frequencies. Then, the inter-correlation sound intensity of all frequencies is fused in the iterative estimation of the target velocity, verifying the proposed method’s ability to suppress the background noise when performing multi-frequency processing. The simulation results show that the proposed method is still effective in estimating the target velocity when the CS method fails and that the performance of the proposed method is better than the CS method with a decrease in SNR. As verified using the SWellEx-96 sea trial dataset, the RMSE of the proposed method for surface vessel speed measurement is 0.3545 m/s, which is 46.1% less than the traditional CS method, proving the feasibility and effectiveness of the proposed SBL-CS method for the estimation of the radial speed of a passive target. Full article

Gridless direction of arrival (DOA) estimation methods have garnered significant attention due to their ability to avoid grid mismatch errors, which can adversely affect the performance of high-resolution DOA estimation algorithms. However, most existing gridless methods are primarily restricted to applications involving uniform linear arrays or sparse linear arrays. In this paper, we derive the relationship between the element-domain covariance matrix and the angular-domain covariance matrix for arbitrary array geometries by expanding the steering vector using a Fourier series. Then, a deep neural network is designed to reconstruct the angular-domain covariance matrix from the sample covariance matrix and the gridless DOA estimation can be obtained by Root-MUSIC. Simulation results on arbitrary array geometries demonstrate that the proposed method outperforms existing methods like MUSIC, SPICE, and SBL in terms of resolution probability and DOA estimation accuracy, especially when the angular separation between targets is small. Additionally, the proposed method does not require any hyperparameter tuning, is robust to varying snapshot numbers, and has a lower computational complexity. Finally, real hydrophone data from the SWellEx-96 ocean experiment validates the effectiveness of the proposed method in practical underwater acoustic environments. Full article

Time-dependent deformation in nuclear graphite is influenced by the creation and migration of radiation-induced defects in the reactor environment. This study investigates the role of pre-existing defects such as point defect clusters and Mrozowski cracks in nuclear graphite IG-110. Separate specimens were irradiated with a 2.8 MeV Au²⁺ beam with a fluence of 4.38 × 10¹⁴ cm⁻² and an 8 MeV C²⁺ beam with a fluence of 1.24 × 10¹⁶ cm⁻². Microscopic specimens were either mechanically loaded inside a transmission electron microscope (TEM) or subjected to ex situ indentation-based creep loading. In situ TEM tests showed significant plasticity in regions highly localized around the Mrozowski cracks, resembling slip or ripplocation bands. Slip bands were also seen near regions without pre-existing defects but at very high stresses. Ex situ self-ion irradiation embrittled the specimens and decreased the creep displacement and rate, while heavy ion irradiation resulted in the opposite behavior. We hypothesize that the large-sized gold ions (compared to the carbon atoms) induced interplanar swelling as well as cross-plane channels for increased defect mobility. These findings illustrate the role of pre-existing defects in the dynamic relaxation of stresses during irradiation and the need for more studies into the radiation environment’s impact on the mechanical response of nuclear graphite. Full article

Early-life nutrition significantly impacts vaccination efficacy in infants, whose immune response to vaccines is weaker compared to adults. This study investigated vaccination efficacy in female C57Bl/6JOlaHsd mice (6 weeks old) fed diets with 0.7% galacto-oligosaccharides (GOS)/long-chain fructo-oligosaccharides (lcFOS) (9:1), 0.3% human milk oligosaccharides (HMOS), or a combination (GFH) for 14 days prior to and during vaccination. Delayed-type hypersensitivity (DTH) was measured by assessing ear swelling following an intradermal challenge. Influvac-specific IgG1 and IgG2a levels were assessed using ELISAs, while splenic T and B lymphocytes were analyzed for frequency and activation via flow cytometry. Additionally, cytokine production was evaluated using murine splenocytes co-cultured with influenza-loaded dendritic cells. Mice on the GFH diet showed a significantly enhanced DTH response (p < 0.05), increased serological IgG1 levels, and a significant rise in memory B lymphocytes (CD27+ B220+ CD19+). GFH-fed mice also exhibited more activated splenic Th1 cells (CD69+ CXCR3+ CD4+) and higher IFN-γ production after ex vivo restimulation (p < 0.05). These findings suggest that GOS/lcFOS and HMOS, particularly in combination, enhance vaccine responses by improving memory B cells, IgG production, and Th1 cell activation, supporting the potential use of these prebiotics in infant formula for better early-life immune development. Full article