Search Results (4,647)

Ultraviolet B radiation is a major cause of skin aging, cellular senescence, and inflammaging, mediated by the excessive production of reactive oxygen species (ROS) and induction of apoptosis. This study evaluated the photo-protective effects of astaxanthin, one of the strongest natural antioxidants, in UVB-treated keratinocytes. The antioxidant capacity of astaxanthin was evaluated using ABTS, DPPH, and NBT/riboflavin/SOD assays. HaCaT cells were exposed to 30 mJ/cm² of UVB radiation. Photoprotective effects and accumulated ROS were evaluated in UVB-irradiated HaCaT cells by MTT and DCFH-DA assays. Nitric oxide levels were quantified using the Griess reagent. Apoptosis was assessed by dual staining using acridine orange/ethidium bromide, lysosomal integrity by acridine orange uptake, and cell migration by scratch assay. Cell adhesion was assessed on ECM-coated Nunc plates. Finally, we formulated a 0.5% astaxanthin-enriched cream. Astaxanthin mitigated UVB-induced damage by reducing intracellular ROS levels by 3.7-fold, decreasing nitric oxide production to 29.8 ± 7.7% at the highest concentration, and maintaining lysosomal integrity. The carotenoid significantly enhanced cell viability, increasing it from 60.64 ± 8.3% in UV-treated cells to 102.1 ± 3.22% at 40 µM. Moreover, treated cells showed a significant reduction (p < 0.001) in the apoptotic rate (37.7 ± 3.1 vs. 87.7 ± 3.8 in UVB-irradiated cells, as evidenced by reduced chromatin condensation and nuclear fragmentation. Astaxanthin also enhanced tissue repair, as evidenced by increased cell migration and adhesion to several extracellular matrix (ECM) proteins (poly-L-lysine, laminin, fibrinogen, vitronectin and collagen I). In silico molecular docking predicted strong binding affinities between astaxanthin and key cellular targets, including JAK2 (−9.9 kcal/mol, highest affinity), STAT3, FAK, COX-2, NF-k-B, MMP2, and MMP9. The formulated cream demonstrated an in vitro SPF of 7.2 ± 2.5. Astaxanthin acts as a multifunctional photoprotective compound, providing a strong rationale for its incorporation into cosmetic and dermatological formulations, as further supported by the successful formulation and in vitro SPF estimation of an astaxanthin-enriched cream. Full article

The inherent diffraction of electromagnetic waves, such as shortwaves and microwaves, severely limits the effective signal transmission distance, thereby constraining the development of related applications like radar and communications. This work experimentally demonstrates the use of a virtual hyperbolic metamaterial (VHMM) realized via a plasma filament array induced in air by a femtosecond laser. We characterize the ability of this VHMM to control electromagnetic waves in the shortwave and microwave bands, particularly its guiding and collimating effects. By combining experimental measurements with effective medium theory, we confirm that under specific parameters, the principal diagonal components of the permittivity tensor for the plasma array exhibit opposite signs, manifesting typical hyperbolic dispersion characteristics which enable the guiding of electromagnetic waves. This research provides a feasible approach for utilizing lasers to create dynamically reconfigurable and non-physical structures in free space for manipulating long-wavelength electromagnetic radiation, demonstrating potential for applications in areas such as radar, communications, and remote sensing. Full article

Ultraviolet (UV) radiation is a primary environmental factor responsible for skin photodamage, and exposure to UV rays is strongly linked to a variety of skin diseases. This study examined the prophylactic and therapeutic effects of Seed Oil of Lycium barbarum L. from the Qaidam basin (QLBSO) in a UV-induced skin photodamage model in BALB/c mice, exploring potential mechanisms by analyzing the skin microbiota and metabolites using 16S rDNA sequencing and metabolomics. The results showed that QLBSO effectively alleviated UV-induced histopathological changes in mouse skin. It also significantly increased the activity of superoxide dismutase (SOD) and catalase (CAT) in UV-damaged skin tissue, while reducing levels of inflammatory cytokines, including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β), as well as matrix metalloproteinases-1 (MMP-1) and MMP-3. Omics analysis revealed that QLBSO successfully restored the balance of the skin microbiota and corrected disruptions in amino acid metabolism caused by UV exposure. Notably, Firmicutes_A and Kineothrix, along with cysteine, cystine, glycine, arginine, proline, and choline, were identified as key microbial species and metabolites responsive to QLBSO’s prophylactic and therapeutic effects. In conclusion, QLBSO likely protects against UV-induced skin photodamage by modulating the skin microbiota and amino acid metabolism, providing a scientific foundation for its potential use in skin health protection. Full article

A mechanically reconfigurable phased array antenna (MRPA) with switchable radiation and scattering characteristics is presented. By adjusting the height of each array element, a continuous aperture phase response is achieved, enabling mechanical beam steering without electronic phase shifters. In the radiation mode, a height-induced phase gradient is used to steer the beam, while in the scattering mode, the same height–phase mapping mechanism produces multi-element phase cancellation for radar cross-section (RCS) reduction. An 8 × 8 prototype operating at 7.9 GHz is designed and validated. The array achieves beam steering up to ±45° with a peak realized gain of 21.5 dBi and an aperture efficiency of 87.6%. Moreover, more than 10 dB monostatic RCS reduction is obtained over a wide frequency range from 3 to 38 GHz. The proposed design provides a unified mechanical approach for radiation enhancement and scattering suppression in multifunctional phased arrays. Full article

With the growing prominence of skin photodamage caused by ultraviolet (UV) radiation, the development of efficient and safe natural photoprotectants has become a major research focus. Ginsenoside Re (G-Re), a primary active component of ginseng (Panax ginseng C. A. Mey.), has attracted much attention due to its significant antioxidant and anti-inflammatory activities; however, its systemic role and mechanism in protecting against photodamage remain unclear. In this study, a UVB-induced rat photodamage model was established to evaluate the protective effect of ginsenoside Re through histopathological staining, biochemical assay, and immunohistochemical analysis. Furthermore, an integrated transcriptomic and metabolomic approach was applied to elucidate the molecular mechanism of G-Re protection and to establish the association between the photodamage phenotype, metabolic pathways, and gene functions. Following their identification via integrated multi-omics analysis, the key targets were subjected to verification via Western blotting. The results showed that G-Re could effectively alleviate UVB-induced pathological injury and reduce the level of oxidative stress and inflammatory factors, which could reverse regulate the abnormal expression of 265 differential genes and 30 metabolites. The glutathione metabolism pathway was proven as a key pathway mediating the protective effects of ginsenoside Re against skin photodamage via integrated analysis, WB verification, and molecular docking. The current study indicated that G-Re could be a promising natural sunscreen additive in cosmetical products. Full article

Background: In malignant pleural mesothelioma, epithelioid histology is traditionally considered a favorable prognostic marker. However, it remains clinically undetermined whether the intensity of an oncogenic insult can disrupt this link. Radiation-induced cases serve as an unconfounded biological model to dissect such trajectories masked by asbestos confounding. Methods: We performed an Individual Patient Data (IPD) synthesis of 20 strictly asbestos-unexposed human cases, applying clinically established dose stratification (intermediate: 20–45 Gy vs. high: >45 Gy). To confirm the observed pattern, we examined data from 829 dogs in the Colorado State University (CSU) Beagle Study. Results: In the intermediate-dose group (n = 13), a significant positive correlation persisted between age at radiotherapy and the latent period (ρ = 0.567, p = 0.043). Conversely, high-dose exposure (>45 Gy) showed a disruption of this age-dependent pattern, with a trend toward inverse correlation (ρ = −0.754, p = 0.084). Interaction analysis confirmed a statistically significant divergence between these dose-dependent trends (p = 0.005). The CSU Beagle Study (n = 829) demonstrated the physical basis of this phenomenon: in the canine model, high-dose exposure (≥0.74 Gy) triggered a “Step-Jump” in cumulative incidence (30.4% at 0.5 years), indicating instantaneous carcinogenic onset distinct from cumulative biological aging. Conclusions: This kinetic divergence points to a “Diagnostic Trap.” We propose a ‘Single- to Double-Brake’ framework where intermediate doses preserve age-dependent progression, whereas high doses likely trigger catastrophic genomic failure (chromothripsis) that bypasses the time required for morphological dedifferentiation. Consequently, morphologically indolent epithelioid tumors in high-dose survivors may harbor aggressive molecular profiles not predicted by histology alone, necessitating risk-stratified precision surveillance. Full article

While research on high-incidence tumors such as breast, prostate, and lung cancer has led to significant increases in patient survival in recent years, this has not been the case for low-incidence tumors such as high-grade gliomas, the most common and lethal brain tumors, for which the last significant therapeutic advance dates back to 2005. The high infiltration capacity of these tumors into normal brain tissue essential for both vegetative and relational life, the tumor microenvironment, with poor immunological activity, the multiple resistance mechanisms, and the unattractiveness of research investments due to the limited number of patients have made, and continue to make, the path to achieving significant improvements in the survival of patients with high-grade gliomas long and arduous. The objective of this article is to update the slow but continuous radiotherapeutic progress for adult and pediatric high-grade gliomas to the second half of 2023. We analyzed the progress of preclinical and clinical research on both adult and pediatric high-grade gliomas, with a particular focus on improvements in radiotherapy. Interactions between non-radiant new therapies and radiotherapy were also covered. A literature search was conducted in PubMed using the terms (“glioma* and radio*”) and the time limit of 1 July 2023 to 31 December 2023. The inclusion and exclusion criteria for the review were relevance to advances in radiotherapy for high-grade gliomas in adults and children. Treating patients with advanced disease progression only, using “historical” data as controls, as well as repurposing drugs developed for purposes completely different from their intended use, were the major (but not the only) methods to assess risk of bias in the included studies. The effect measures used in the synthesis or presentation of the results were tabulated and/or displayed in figures. A total of 100 relevant references were reviewed. Advances in preclinical studies and in clinical radiotherapy treatment planning, innovative fractionation, use of radioisotopes/radiopharmaceuticals, radiosensitization procedures, and radiation-induced damage were focused on. While this analysis may be limited by the relatively short publication period, high-grade glioma research remains impacted, especially at the clinical level, by potential issues with trial design, such as treating patients with advanced disease progression, using “historical” data as controls, and repurposing drugs developed for completely different purposes than intended. Addressing these aspects of high-grade glioma research could improve its efficacy, which often remains low despite the associated costs. Full article

Background: Melanin protects skin and hair from the effects of ultraviolet (UV) radiation damage, which contributes to all forms of skin cancer, including melanoma. Human melanocytes produce two main types of melanin: eumelanin provides effective photoprotection, and pheomelanin offers less protection against UV-induced skin damage. The agouti signaling protein (ASIP) antagonizes the melanocortin-1 receptor (MC1R), hinders melanocyte signaling, and shifts pigmentation toward pheomelanin, promoting UV vulnerability. In this study, we aim to discover compounds that inhibit ASIP–MC1R interaction and effectively preserve eumelanogenic signaling. Methods: The ASIP–MC1R interface-based pharmacophore model from ASIP is implicated in MC1R receptor protein engagement. We performed virtual screening with a validated pharmacophore model for ~4000 compounds curated from ZINCPharmer and applied drug-likeness filters, viz. ADMET and toxicity profiling tests. Further, the screened candidates were targeted for docking to the ASIP C-terminal domain corresponding to the MC1R-binding moiety. Top compounds underwent a 100-nanosecond (ns) run of molecular dynamics (MD) simulations to assess complex stability and persistence of key contacted residues. Results: Sequential triage, including pharmacophore, ADME–toxicity (ADMET), and docking/ΔG, yielded a focused group of candidates against ASIP antagonists with a favorable fit value. The MD run for 100 ns supported pose stability at the targeted pocket. Based on these predictions and analyses, compound ZINC14539068 was screened as a new potent inhibitor of ASIP to preserve α-MSH-mediated signaling of MC1R. Conclusions: Our in silico pipeline identifies ZINC14539068 as a potent inhibitor of ASIP at its C-terminal interface. This compound is predicted to disrupt ASIP–MC1R binding, thereby maintaining eumelanin-biased signaling. These findings motivate experimental validation in melanocytic models and in vivo studies to confirm pathway modulation and anti-melanoma potential. Full article

The global cancer burden continues to increase worldwide. Among the various treatment options, radiotherapy (RT), which employs high-energy ionizing radiation to destroy cancer cells, is one of the primary modalities for cancer. However, increasing the absorbed dose to the target volume also increases the risk of damage to surrounding healthy tissues. This radiation-induced toxicity to normal tissues limits the desirable dosage that can be delivered to the tumor, thereby constraining the effectiveness of radiation therapy in achieving tumor control. FLASH radiotherapy (FLASH-RT) has emerged as a promising technique due to its biological advantages. FLASH-RT involves the delivery of radiation at an ultra-high dose rate (≥40 Gy/s). Unlike conventional RT, FLASH-RT achieves comparable tumor control rates while significantly reducing damage to surrounding normal tissues, a phenomenon known as the FLASH effect. Although the mechanism behind the FLASH effect is not fully understood, this approach shows considerable promise for future cancer treatment. The development of specialized treatment planning systems (TPS) becomes imperative to facilitate the clinical implementation of FLASH-RT from experimental studies. These systems must account for the unique characteristics of FLASH-RT, including ultra-high dose rate delivery and its distinctive radiobiological effects. Critical reassessment and optimization of treatment planning protocols are essential to fully leverage the therapeutic potential of the FLASH effect. This review examines key considerations for the TPS development of electron and proton FLASH-RT, including electron and proton FLASH techniques, biological models, crucial beam parameters, and dosimetry, providing essential insights for optimizing TPS and advancing the clinical implementation of this promising therapeutic modality. Full article

Drought is a pervasive and intensifying climate hazard with profound implications for food security, water availability, and socioeconomic stability, particularly in sub-Saharan Africa. In Kenya, where over 80% of the landmass comprises arid and semi-arid lands (ASALs), recurrent droughts have become a critical threat to agricultural productivity and climate resilience. This study presents a comprehensive spatiotemporal analysis of seasonal drought dynamics in Kenya for June–July–August–September (JJAS) from 2000 to 2024, leveraging remote sensing-based drought indices and geospatial analysis for climate risk planning. Using the Standardized Precipitation Evapotranspiration Index (SPEI), Vegetation Condition Index (VCI), Soil Moisture Anomaly (SMA), and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) anomaly, a Combined Drought Indicator (CDI) was developed to assess drought severity, persistence, and impact across Kenya’s four climatological seasons. Data were processed using Google Earth Engine and visualized through GIS platforms to produce high-resolution drought maps disaggregated by county and land-use class. The results revealed a marked intensification of drought conditions, with Alert and Warning classifications expanding significantly in ASALs, particularly in Garissa, Kitui, Marsabit, and Tana River. The drought persistence analysis revealed chronic exposure in drought conditions in northeastern and southeastern counties, while cropland exposure increased by over 100% while rangeland vulnerability rose nearly 56-fold. Population exposure to drought also rose sharply, underscoring the socioeconomic risks associated with climate-induced water stress. The study provides an operational framework for integrating remote sensing into early warning systems and policy planning, aligning with global climate adaptation goals and national resilience strategies. The findings advocate for proactive, data-driven drought management and localized adaptation interventions in Kenya’s most vulnerable regions. Full article

Cryptochromes (CRYs) are a conserved class of blue light and near-ultraviolet light receptors that regulate diverse processes, including photomorphogenesis in plants. In the extreme Antarctic environment, ice algae endure intense UV radiation, prolonged darkness, and low temperatures, where cryptochromes play a vital role in light sensing and stress response. In this study, we cloned the complete open reading frame (ORF) of the cryptochrome gene CiCRY-DASH1 from the Antarctic microalga Chlamydomonas sp. ICE-L. Both in vivo and in vitro DNA photorepair assays showed that CiCRY-DASH1 effectively repairs cyclobutane pyrimidine dimer (CPD) and 6-4 photoproducts (6-4PPs) induced by UV radiation. Furthermore, deletion of the N-terminal and C-terminal loop regions, combined with activity assays, revealed that the C-terminal loop region plays a crucial role in photorepair activity. These findings elucidate the adaptive photorepair mechanisms of Antarctic microalgae and establish CiCRY-DASH1 as a valuable genetic resource. Specifically, the high catalytic efficiency and evolutionary robustness of the engineered variants position it as a promising marine bioactive agent for photoprotective therapeutics and a strategic target for constructing microbial chassis to enable sustainable drug biomanufacturing. Full article

Ionizing radiation remains the primary approach for treating brain cancer and is frequently used in combination with chemotherapy. However, when it comes to gliomas, the effective delivery of therapeutic agents is hindered by the limited permeability of the blood–brain barrier (BBB). Consequently, selecting the most suitable and least harmful type of ionizing radiation is essential, given its potential side effects on healthy cells within the tumor microenvironment. In this study, we explored the impact of X-ray exposure on two in vitro BBB endothelial cell models—murine and human. Post-irradiation, we evaluated cell viability, clonogenic capacity, cell cycle progression, reactive oxygen species (ROS) levels, formation of micronuclei and γ-H2AX foci, as well as alterations in cytoskeletal organization, cell migration, and intracellular calcium dynamics. The results demonstrate notable differences between the two endothelial cell lines, suggesting the human cell line is more sensitive to X-rays. In conclusion, our study provides valuable insights into the brain microvascular endothelial cells’ response to radiation, laying the groundwork for strategies to protect healthy brain tissue. Full article

This work demonstrates a three-step method for the synthesis and production of submicron spherical gold particles using laser ablation in liquid (LAL), laser-induced fragmentation in liquid (LFL), laser-induced nanochain formation, and laser melting in liquid (LML). The nanoparticles were characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), and UV–visible spectroscopy. In the first stage, spherical gold nanoparticles with a size of 20 nm were obtained using LAL and LFL. Subsequent irradiation of gold nanoparticle colloids with radiation at a wavelength of 532 nm leads to the formation of gold nanochains. Irradiation of nanochain colloids with radiation at a wavelength of 1064 nm leads to the formation of large spherical gold particles with a size of 50 to 200 nm. The formation of submicron gold particles upon irradiation of 2 mL of colloid occurs within the first minutes of irradiation and is complete after 480,000 laser pulses. Increasing the laser pulse energy leads to the formation of larger particles; after exceeding the threshold energy (321 mJ/cm²), fragmentation is observed. Increasing the concentration of nanoparticles in the initial colloid up to 150 μg/mL leads to a linear increase in the size of submicron nanoparticles. The use of picosecond pulses for irradiating nanochains demonstrates the formation of the largest particles (200 nm) compared to nanosecond pulses, which may be due to the effect of local surface melting. The described technique opens the possibility of synthesizing stable gold nanoparticles over a wide range of sizes, from a few to hundreds of nanometers, without the use of chemical reagents. Full article

Background/Objectives: Although Tumor-Treating Fields (TTFields) therapy is an established treatment modality for adult glioblastoma, clinical data on its efficacy in pediatric brain tumors are extremely scarce. The present study aimed to evaluate the safety of TTFields therapy for pediatric diffuse high-grade glioma (HGG) and to conduct an exploratory analysis of its efficacy. Methods: A prespecified, interim analysis was performed to determine whether the study should be continued on the basis of safety and feasibility data on the first three patients. The target population was children aged 5 to 17 years with newly diagnosed, supratentorial HGG or its first recurrence following frontline therapy. After completion of initial, local treatment for the tumor (surgical removal and/or radiotherapy), all patients received TTFields therapy using Optune^TM for 28 days per course for up to 26 courses until disease progression. Results: The interim analysis, which was completed in October 2022, included three female patients aged 14, 17, and 9 years. All had a histological grade 4 tumor, two of which were radiation-induced, secondary HGG. No serious, treatment-related toxicities or device-related issues were observed. All three patients were able to continue using the device for 75% or more of the time in accordance with the protocol, suggesting that the treatment was feasible. The MRI findings of two patients indicated that the treatment has a potential antitumor effect. Based on these results, the study was resumed and is currently being continued at multiple centers. Conclusions: The initial results of the prespecified, interim analysis demonstrated that TTFields therapy was safe and feasible for children with HGG. This study was funded by the Japan Agency for Medical Research and Development (AMED) and was registered with the Japan Registry of Clinical Trials (jRCTs032200423). Full article

To investigate the in situ irradiation effects of gallium nitride at varying temperatures, we combined ion beam-induced luminescence spectroscopy with variable-temperature irradiation using a home-built IBIL system and a GIC4117 2 × 1.7 MV tandem accelerator. Unlike previous static studies—limited to post-irradiation or single-temperature luminescence—we in situ tracked dynamic luminescence changes throughout irradiation, directly capturing the real-time responses of luminescent centers to coupled temperature-dose variations—a rare capability in prior work. To clarify how irradiation and temperature affect the luminescent centers of GaN, we integrated density functional theory (DFT) calculations with literature analysis, then resolved the yellow luminescence band into three emission centers via Gaussian deconvolution: 1.78 eV associated with C/O impurities, 1.94 eV linked to VGa, and 2.2 eV corresponding to CN defects. Using a single-exponential decay model, we further quantified the temperature- and dose-dependent decay rates of these centers under dual-variable temperature and dose conditions. Experimental results show that low-temperature irradiation such as at 100 K suppresses the migration and recombination of V_Ga/C_N point defects, significantly enhancing the radiation tolerance of the 1.94 eV and 2.2 eV emission centers; meanwhile, it reduces non-radiative recombination center density, stabilizing free excitons and donor-bound excitons, thereby improving near-band-edge emission center resistance. Notably, the 1.94 eV emission center linked to gallium vacancies exhibits superior cryogenic radiation tolerance due to slower defect migration and more stable free exciton/donor-bound exciton states. Collectively, these findings reveal a synergistic regulation mechanism of temperature and radiation fluence on defect stability, addressing a key gap in static studies, providing a basis for understanding degradation mechanisms of gallium nitride-based devices under actual operating conditions (coexisting temperature fluctuations and continuous radiation), and offering theoretical/experimental support for optimizing radiation-hardened gallium nitride devices for extreme environments such as space or nuclear applications. Full article