This study introduces a novel gamma-irradiation-induced synthesis strategy to fabricate a magnetic carboxymethyl guar gum/poly(acrylic acid)/kaolinite (Fe3O4@CMGG/PAAc/NC) hydrogel for efficient Cr(VI) removal. Unlike previously reported guar gum or Fe3O4-based hydrogels, this work integrates three unique features: (i) a one-pot, initiator-free gamma-irradiation process that enables simultaneous grafting and crosslinking without chemical initiators or toxic residues, (ii) the use of kaolinite nanoclay as a natural reinforcement to enhance mechanical stability and functional group availability, and (iii) atomic force microscopy (AFM)-guided optimization of nanoclay and Fe3O4 contents, establishing a new approach for morphology-controlled hydrogel design. The optimized composite containing 3 wt% Fe3O4 and 0.3 g NC exhibited superior adsorption capacity and magnetic recoverability. Characterization (FTIR, XRD, TEM, SEM-EDX, and AFM) confirmed homogeneous nanoparticle dispersion, enhanced surface area, and functional group synergy within the polymer matrix. Adsorption kinetics followed a pseudo-second-order model, while the Freundlich isotherm indicated multilayer chemisorption on a heterogeneous surface. The nanocomposite achieved 98 % Cr(VI) removal efficiency at pH 6, maintaining over 84 % reusability after five cycles. This work demonstrates how gamma irradiation coupled with AFM-driven optimization can create multifunctional, sustainable hydrogels, marking a significant advancement beyond conventional guar gum-based or chemically crosslinked adsorbents for real-world wastewater remediation.
Ionizing radiation provides a typical solution to facilitate the cellulose extraction process and determine different molecular weights of the resulting cellulose. This study presents an innovative approach to extracting cellulose from sawdust after gamma irradiation as a pretreatment step. Sawdust was exposed to gamma irradiation at doses of 0, 20, 40, 60, 80, and 100 kGy, notably affecting the extraction efficiency and cellulose functionality. After irradiation, it underwent mercerization and etherification to yield sodium carboxymethyl cellulose (NaCMC). The properties of the resulting Na-CMC were studied, and analysis revealed dose-dependent effects on the structural and chemical properties. The viscosity average molecular weight experiment illustrated a rapid decrease in molecular weight of the prepared Na-CMC by increasing doses up to 60 kGy. XRD and degree of substitution (DS) analysis indicated that radiation up to 60 kGy notably enhanced the crystallinity, and the highest DS was obtained, which improved the functional properties and water solubility. NMR and FTIR spectra confirmed the success of the carboxymethylation process, while TGA and LC-MS demonstrated the effects of irradiation on thermal stability and degree of substitution. EDX analysis confirmed changes in the elemental composition. This comprehensive exploration identifies 60 kGy as the optimal dose and provides detailed insights into the role of gamma radiation in improving Na-CMC production. The degree of substitution increased, and the molecular weight decreased while retaining the chemical structure of Na-CMC, which greatly enhances the industrial scalability and performance of the material.
Vegetation cover dynamics is one of the key indicators of ecosystem functioning, land degradation processes, and climate-driven environmental changes, especially in regions with sharply continental and semi-arid climates. Many existing drought-related studies mainly focus on short-term anomalies, seasonal variability, or individual drought events, which often limits the ability to identify persistent long-term trends and the cumulative vegetation response to hydrothermal conditions. For regions characterized by pronounced interannual climate variability, this limitation may lead to an underestimation of gradual processes of vegetation degradation or recovery. This study presents a methodology for monitoring the spatio-temporal dynamics of vegetation cover on rainfed lands in Northern Kazakhstan for the period 2000–2023. The proposed approach is based on long-term time series of vegetation indices. Satellite-derived vegetation indices are widely used for vegetation monitoring, drought assessment, and the analysis of long-term environmental trends at regional and global scales. Among them, Normal Differential Vegetation Index (NDVI), Vegetation Condition Index (VCI), have proven to be effective tools for detecting vegetation stress during the growing season. The Integral Vegetation Index (IVI) and the Integral Vegetation Condition Index (IVCI) are designed to rank growing seasons according to drought severity within a long-term observation period and to identify interseasonal vegetation trends associated with climatic factors. Their computational and interpretative simplicity makes them efficient analytical tools. The use of IVCI enables a comprehensive assessment of drought intensity through vegetation response to weather-related stress, facilitates the analysis of interseasonal changes in the influence of meteorological conditions on vegetation, and provides a more complete representation of vegetation dynamics compared to traditional approaches. In addition, this approach allows the identification of persistent zones of vegetation change and supports spatial zoning of territories according to their sensitivity to drought conditions in the northern regions of Kazakhstan. All indices were calculated using 8-day MODIS composite data (MOD09Q1) with a spatial resolution of 250 m for the growing seasons from 2000 to 2023. The results were validated using correlation analysis between IVCI and the ground-based Selyaninov Hydrothermal Coefficient (HTC). The findings revealed strong to very strong correlations in Kostanay region (at more than 75
The article presents a technology for producing composite thermal insulation material based on AG-4B by stepwise hot pressing for nozzle assemblies of small-sized rocket engines. Five samples were produced at different combinations of pressure, temperature and exposure time. During the transition from sample 1 to 4, a consistent improvement in the complex of properties was recorded: density increased from 1.59 to 1.76 g/cm3 (+10.7
Background: Knee osteoarthritis (OA) causes pain, stiffness, and reduced mobility, significantly impairing quality of life. Low-dose radiotherapy (LDRT) has emerged as a potential treatment due to its anti-inflammatory and immunomodulatory effects, but its efficacy in specific populations, such as breast cancer survivors, remains under studied. Aim of the work: To evaluate the effectiveness and safety of LDRT in female breast cancer survivors with knee OA (grades II and III), focusing on pain relief, inflammation, joint function, and genotoxicity. Patients and methods: Out of an initial 36 patients, 20 (aged 45-65) were divided into two groups: Group I received 0.5 Gy LDRT three times weekly for two weeks, while Group II received 0.5 Gy twice weekly for three weeks. Outcomes were assessed using the Western Ontario and McMaster Universities Arthritis (WOMAC) index, erythrocyte sedimentation rate (ESR), genotoxicity tests (Micronucleus and Comet assays), and magnetic resonance imaging (MRI) for cartilage thickness and joint space. Results: Both the LDRT regimens significantly improved WOMAC, reduced pain, stiffness, and enhanced joint function. Inflammatory markers showed a non-significant decline, suggesting mild anti-inflammatory effects. Genotoxicity tests indicated minimal DNA damage, particularly in Group II, confirming safety. MRI revealed improved cartilage thickness and morphology without significant joint effusion changes. The two dosing schedules were comparable. Conclusion: LDRT, particularly 0.5 Gy twice weekly for three weeks, is an effective and safer treatment for knee OA in breast cancer survivors, providing symptoms relief and cartilage improvement with low toxicity. Further large-scale trials are needed to refine protocols and confirm optimal dosing.
