Search Results (810)

Gas nitriding was implemented in the current work at a constant nitrogen potential (K_N) of 2.0 for 8 h to enhance the fatigue properties of SCM 440 steel, and the results were compared with those of the substrate tempered at the nitriding temperature (475 °C). Fine particle peening (FPP) prior to nitriding imposed a refined structure and induced compressive residual stress (CRS) in the near-surface peened zone. The fine-grained structure provided numerous paths to enhance nitrogen diffusion inwards during nitriding. The compound layer formed on the nitrided SCM 440 steel primarily comprised a mixture of Fe₃N and Fe₄N; however, the pre-peened and nitrided (SPN) specimens exhibited a higher proportion of Fe₃N and a thicker compound layer than the non-peened and nitrided (NPN) counterparts. In addition, FPP prior to nitriding increased both the case depth and the magnitude of the CRS field compared with nitriding alone. The fatigue limits of the substrate (SB), NPN, and SPN samples were approximately 750, 1050, and 1400 MPa, respectively. Gas-nitriding at 475 °C significantly improved the fatigue performance of SCM 440 steel. Moreover, pre-peening prior to nitriding further enhanced fatigue strength and life of the treated SCM 440 steel by introducing a deeper case depth and higher CRS field. Multiple cracks initiation at the outer surface of the SB sample accounted for its lowest fatigue limit among the tested samples. Surface microcracks and pits on the surface of the NPN specimen would be crack initiation sites and harmful to its fatigue resistance. These surface dents were considered to be responsible for fatigue crack initiation in the SPN specimens. Therefore, polishing after nitriding to reduce surface roughness and/or microcracks was expected to further increase the fatigue resistance and the reliability of nitrided SCM 440 steel. Full article

NiTi alloys are widely used in biomedical applications due to their shape memory and superelastic properties. However, their surface reactivity requires protective, biofunctional coatings. To enhance NiTi performance, its surface was modified with an Ag-SiO₂-TiO₂ nanocoating containing small amounts of silica and silver. The coating’s primary phase was rutile with structural defects and a silver solid solution. It showed good adhesion, high scratch resistance, and improved corrosion behavior in Ringer’s solution, as demonstrated by EIS and cyclic polarization. EIS revealed high low-frequency impedance and two time constants, suggesting both barrier protection and slower electrochemical processes. Despite low breakdown and repassivation potentials, the coating effectively limited uniform corrosion. SEM/EDS confirmed localized degradation and partial substrate exposure, while elemental mapping showed well-dispersed silica and silver in a TiO₂-rich matrix. The proposed pitting mechanism involves chloride-induced depassivation and galvanic effects. Surface potential mapping indicated electrostatic heterogeneity, mitigated by silica. The coating offers a balanced combination of corrosion protection and biofunctionality, supporting its potential for implant use. Full article

Aquaculture is an important food sector, which involves the commercial production of fish for consumption. Tilapias (Oreochromis sp.) are hardy and are one of the most commonly produced fishes in the aquaculture industry. Disease outbreaks caused by Streptococcus agalactiae, however, widely affect tilapia farms, resulting in high mortality. Consequently, this may lead to the misuse of antibiotics for the prevention of disease or overuse of antibiotics when used for the treatment of fishes, contributing to antibiotic resistance. In this study, date palm pits, a waste product from the date palm industry, were tested for potential antibacterial activity against S. agalactiae and for their ability to act as an immune enhancer in vitro through the use of the head kidney and serum from healthy adult tilapias. An in vivo study was performed by dividing tilapias into two groups, consisting of infected S. agalactiae and uninfected S. agalactiae. Each group consisted of extract-fed and distilled-water-fed tilapia. Then, the serum, spleen and head kidney were isolated from both groups and tested for their respiratory burst, lysozyme and myeloperoxidase activities. The results from this study indicate that the Raziz methanol extract at a concentration of 1 g/mL inhibited the growth of S. agalactiae, and concentrations of 10 mg/mL, 2 mg/mL and 0.016 mg/mL displayed the highest respiratory burst, lysozyme and myeloperoxidase activities, respectively, in vitro. In the infected group, extract-fed tilapias showed a significant effect on respiratory burst activity and lysozyme activity compared to the distilled-water-fed tilapias, while no significant activity was observed in the uninfected group. In conclusion, the Raziz methanol extract has promising potential to act as an antibacterial agent, and it enhanced the innate immune function during active infection of S. agalactiae. Full article

This study aims to evaluate the corrosion behavior of and morphological changes in S235JR steel exposed to 0.5 M hydrochloric acid solution over a period of 24 weeks. Corrosion resistance was assessed through weight loss measurements and electrochemical techniques (such as open circuit potential (OCP), polarization resistance (R_p), and corrosion rate (V_corr)), while surface morphology, elemental analysis, roughness, and Vickers hardness were also analyzed. All evaluations were performed at the same immersion intervals: 2, 4, 8, 12, and 24 weeks. The corrosion rate started at 0.9 mm/year after the first hour of immersion, then decreased due to the formation of corrosion products on the steel surface, and fluctuated during prolonged exposure, reaching a maximum of 8.5 mm/year after 24 weeks. Weight loss increased gradually during the first 8 weeks, followed by a more pronounced rise. Polarization resistance and corrosion rate exhibited dynamic variations. SEM analysis revealed severe surface degradation, including cracks and deep pits. Surface roughness increased significantly from an initial value of 0.91 μm to 9.03 μm at 24 weeks. Vickers hardness dropped from 148.7 HV0.5 to 87.3 HV0.5, due to non-uniform corrosion product formation. These findings highlight the progressive deterioration of S235JR steel in acidic environments and provide valuable insight into its long-term corrosion resistance. Full article

Background/Objective: US military personnel deployed to the Middle East were potentially subjected to harmful exposures, such as carcinogens from burn pits, which may increase the risk of lymphoid malignancies. Our objective was to determine the association between deployment and the risk of developing lymphoid malignancies. Methods: This was a retrospective nested matched case-control study from a cohort of 3.5 million veterans who enlisted in the military after September 2001 and were followed until death or last follow up through September 2024. Cases of lymphoid malignancies were identified by the VA Central Cancer Registry and controls were randomly selected from the same base cohort, matched by year of birth, year of enlistment, sex, race, and ethnicity. Exposure was defined as deployment to the Middle East as determined by identification on the VA Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) roster with confirmed dates of deployment or paystubs. Results: There were 1037 cases of lymphoid malignancies and 3572 matched controls. Deployment was not associated with a higher risk of developing lymphoid malignancies compared to non-deployment. Exposure to OEF/OIF was not associated with a higher risk of developing certain types of lymphoid malignancies. Conclusions: In this large, matched case-control study of US veterans, deployment to the Middle East was not associated with increased risk of developing lymphoid malignancies. While these findings do not support an increased lymphoid malignancy risk, important limitations remain, including the absence of detailed exposure and potential confounding variables. Prospective monitoring of specific types and doses of exposures during military deployment, development of lymphoid and other malignancies, and their underlying pathophysiology is indicated. Full article

Tin mining has played a central role in Indonesia’s economy, particularly in the Bangka Belitung Islands, but it has also caused severe environmental and socio-economic impacts. This study aims to critically review the consequences of tin mining and evaluate reclamation initiatives through a narrative literature review of scientific publications, technical reports, and policy documents. The findings show that open-pit mining has led to deforestation, biodiversity loss, environmental degradation, and decreased soil fertility, while weak governance has fueled illegal mining and social conflicts. Rehabilitation strategies such as reforestation, agroforestry, aquaculture, and soil improvement have the potential to restore or reclaim degraded land and are proposed as a viable pathway to balance ecological improvement with socio-economic development. This study focuses on its interdisciplinary approach, integrating ecological, socio-economic, and institutional perspectives to propose a comprehensive, ecosystem-based framework for post-mining reclamation. By highlighting both challenges and opportunities, the study provides actionable insights for policymakers, mining companies, and local communities. Full article

Timely and reliable surface deformation monitoring is critical for hazard prevention and resource management in mining areas. However, traditional Time-Series Interferometric (TSI) Synthetic Aperture Radar techniques often suffer from low coherent point density in mining environments, limiting their effectiveness. To overcome this limitation, we propose an adaptive Polarimetric TSI (PolTSI) method that exploits dual-polarization Sentinel-1 data to achieve more reliable deformation monitoring in complex mining terrains. The method employs a dual-strategy optimization: amplitude dispersion–based optimization for Permanent Scatterer (PS) pixels and minimum mean square error (MMSE)-based polarimetric filtering followed by coherence maximization for Distributed Scatterer (DS) pixels. Experimental results from an open-pit mining area demonstrate that the proposed approach significantly improves phase quality and spatial coverage. In particular, the number of coherent monitoring points increased from 31,183 with conventional TSI to 465,328 using the proposed approach, corresponding to a 1392% improvement. This substantial enhancement confirms the method’s robustness in extracting deformation signals from low-coherence, heterogeneous mining surfaces. As one of the few studies to apply Polarimetric InSAR (Pol-InSAR) in active mining regions, our work demonstrates the underexplored potential of dual-pol SAR data for improving both the spatial density and reliability of time-series deformation mapping. The results provide a solid technical foundation for large-scale, high-precision surface monitoring in complex mining environments. Full article

This study investigates slope stability in an open-pit mining area by integrating engineering geological surveys, field investigations, and laboratory rock mechanics tests. A coordinated multimethod analysis was carried out using finite element-based numerical simulations from both two-dimensional and three-dimensional perspectives. The integrated approach revealed deformation patterns across the slopes and established a multiscale analytical framework. The results indicate that the slope failure modes primarily include circular and compound types, with existing step slopes showing a potential risk of wedge failure. While the designed slope meets safety requirements under three working conditions overall, the strongly weathered layer in profile XL3 requires a slope angle reduction from 38° to 37° to comply with standards. Three-dimensional simulations identify the main deformations in the middle-lower sections of the western area and zones B and C, with faults located at the core of the deformation zone. Rainfall and blasting vibrations significantly increase surface tensile stress, accelerating deformation. Although wedges in profiles XL1 and XL4 remain generally stable, coupled blasting–rainfall effects may still induce potential collapse in fractured areas, necessitating preventive measures such as concrete support and bolt support, along with real-time monitoring to dynamically optimize reinforcement strategies for precise risk control. Full article

Porous aluminum alloys are widely used for lightweight structural materials such as marine structures, energy absorbers, and buoyant components. However, the conventional foaming agent TiH₂ presents limitations such as high cost and elevated decomposition temperatures, which increase manufacturing costs and restrict industrial applicability. In addition, the utilization of recycled raw materials such as aluminum machining chips has emerged as an important challenge in material development for resource efficiency and sustainability. To address these issues, porous aluminum alloys were fabricated in this study using recycled A356 aluminum chips by incorporating TiH₂ and a low-cost alternative foaming agent, Na₂B₄O₇·10H₂O (borax), either individually or in combination. The effects of foaming agent content (1, 1.5, and 3 wt.%) on pore characteristics, microstructure, hardness, and corrosion resistance were systematically investigated. TiH₂ induced an increase in porosity due to hydrogen generation and also promoted grain refinement, which contributed to the improvement of hardness and corrosion resistance, while Na₂B₄O₇·10H₂O exhibited effective pore formation and hardness improvement at 1–1.5 wt.% but tended to deteriorate corrosion resistance as its content increased. In particular, combined addition of both agents at 1.5 wt.% showed excellent pore formation and corrosion resistance properties, with a relatively high pore area fraction (2.38%), porosity (27.0%), SDAS (48.1 ± 4.8 µm), hardness (59.35 ± 6.4 HV), corrosion potential (−1.039 V), pitting potential (−0.709 V), and corrosion current density (4.956 μA/cm²). This study demonstrated that Na₂B₄O₇·10H₂O (borax) foaming agent can be an economic alternative to TiH₂, and shows that the performance of porous aluminum alloys can be effectively improved by optimizing the combination of recycled raw materials and foaming agents. Full article

Near-infrared photoimmunotherapy (NIR-PIT) is a recently developed cancer treatment that utilizes antibody–photoabsorber (IRDye700DX [IR700]) conjugates and NIR light. Necrotic cell death associated with lethal membrane damage is induced when this conjugate binds to an antigen on cancer cells, and it is exposed to NIR light. Therefore, various membrane proteins are potential therapeutic targets for NIR-PIT, and many studies have described various target molecules and specific antibodies. To develop future drugs for NIR-PIT, the selection of appropriate target membrane proteins and monoclonal antibodies will be important. In this review, we summarize the membrane targets and antibodies for NIR-PIT used in previous studies, focusing on the characteristics of each molecule. Full article

This study applies statistical approaches utilizing linear regression and artificial neural networks (ANNs) to predict the corrosion behavior of austenitic stainless steels (316L, 904L, and AL-6XN) under various environmental conditions. The environmental variables considered include temperature (30–90 °C), chloride ion concentration (20–40 g/L), and pH (2–6). Analysis of variance (ANOVA) confirmed that the input variables, including the Pitting Resistance Equivalent Number (PREN ranging from 24 to 45), significantly affect the critical pitting potential. The influence of the variables was ranked in the order: PREN, temperature, pH, and chloride ion concentration. A linear regression model was developed using significant factors and interactions identified at the 95% confidence level, achieving a predictive performance with R² = 0.789 for critical pitting potential. To predict potentiodynamic polarization curves, an ANN based on supervised learning with backpropagation was employed. The ANN model demonstrated a remarkably high predictive performance with R² = 0.972 in complex corrosion environments. The predicted polarization curves reliably estimated electrochemical characteristics such as corrosion current, corrosion potential, and pitting potential. These results provide a valuable tool for predicting and understanding the corrosion behavior of stainless steels, which can aid in corrosion prevention strategies and material selection decisions. Full article

Dental caries remains one of the most prevalent global diseases, and the early detection of occlusal lesions is critical because demineralization often begins deep within pits and fissures where conventional visual–tactile or radiographic inspection cannot detect it. SmarTooth, a newly introduced fluorescence device that irradiates enamel with a 655 nm laser and records the reflected intensity, may provide more objective, quantitative diagnoses. This study assessed its diagnostic performance against the International Caries Detection and Assessment System (ICDAS). We examined 1421 occlusal surfaces from 153 adults, scored each surface with ICDAS codes 0–4, and recorded SmarTooth peak values. Spearman’s rank correlation was used to test the association between codes and peak values; one-way ANOVA with Tukey’s post hoc was used to compare mean values across codes; and sensitivity, specificity, and the area under the receiver operating characteristic curve (AUROC) were calculated at three diagnostic thresholds: D1 (0 vs. 1–4), D2 (0–2 vs. 3–4), and D3 (0–3 vs. 4). The SmarTooth values rose with lesion severity and correlated moderately with ICDAS (r = 0.495, p < 0.001). The AUROC ranged from 0.69 to 0.82, with the best accuracy observed at D2 (cut-off: 7.0; AUC: 0.82; sensitivity: 78.3%; specificity: 77.4%). These findings suggest that SmarTooth can complement ICDAS scoring as an adjunctive tool, potentially enhancing diagnostic accuracy and supporting early intervention for occlusal caries in general dental practice. Full article

Mining activities caused heavy metal enrichment in mine soils. Sixty-six soil samplings of 26 mines in the central Tianshan Mountains of China were conducted to reveal heavy metal pollution for the single-factor (P_i), Nemerow comprehensive pollution (P_N), geo-accumulation (I_geo), potential ecological risk (E_i), and health risks. The results indicate that mines in Bayingolin and Aksu exhibit the most severe pollution (P_N = 26.64 and 25.28), characterized by Cd (P_i = 115.18) and As (P_i = 67.20), forming a Cd-As compound pattern. While Ili mines show Ni-Cu co-exceedance, and Turpan mines have lower overall pollution but localized Cd enrichment. Additionally, Cd is identified as the most severe by I_geo, with moderate or higher pollution levels observed in 61.00% of samplings. The E_i assessment revealed that Cd posed the greatest threat, with 100%, 53.80%, and 30.70% of samplings indicating slight, high, and extremely high ecological risk levels, respectively. Health risk assessment indicated that non-carcinogenic risks were dominated by Cr (affecting 19.20% of samplings), while carcinogenic risks were primarily from As (7.70%) and Cd (11.50% of samplings), with Cr exhibiting the highest carcinogenic risk. Furthermore, comparative analysis showed that underground mines led to higher pollution levels (I_geo) for Cd, Cu, Mn, Pb, and Zn compared to open-pit mines, and metal mines incurred greater heavy metal(loid) contamination than non-metal mines. These findings could provide data for mine soil pollution remediation in the central Tianshan Mountains. Full article

Bioregions are examples of true sustainable development. The desire for sustainability within local communities leads to agreements and the formation of bioregions in which sustainable development is based on practical action. This paper analyzes the concept of bioregions, emphasizing holistic approaches applied to, and relationships with, economic, environmental and social factors in pathways and the pace of specialization for the development of territories, thereby complementing the agricultural dimension and paying special attention to the application of organic farming techniques. The formation of bioregions is based on the desires of local communities, but at the same time, we believe that there are objective factors that influence the development of bioregions. Thirteen factors that could affect the creation of bioregions were selected using factors referred to in research papers, as well as by adding original ones. These factors can be divided into the sustainable agriculture and tourism groups, in which high values indicate a high potential for the formation of bioregions, as well as the intensive agriculture factor group, where high values indicate the benefits of large-scale economies that hinder the formation of bioregions. Cluster analysis identified six potential bioregions in Latvia, each with distinct socio-economic, environmental, and agricultural characteristics: the metropolitan region (dominant indicator-PIT per capita, value 890 EUR), the tourism cluster (dominant indicator—tourists served as a % of the total population, value 28%), the extensive agriculture cluster (dominant indicator—organically certified UAA, value 14,645 ha), the nature and education cluster (dominant indicator—protected areas, value 7587 ha), the intensive agriculture cluster (dominant indicator—profit from productive land, value 278 EUR ha⁻¹), as well as a non-specialized cluster (no strongly dominant indicators). This paper describes each cluster and discusses its potential for bioregion development. Full article

The depletion of shallow coal reserves necessitates a shift from open-pit to underground mining, increasing the need for safe and efficient backfill systems. However, traditional backfill materials—especially cement—are costly and environmentally burdensome. To address this, our study explores a sustainable alternative using industrial waste, contributing to the principles of a circular economy. This research presents a novel backfill formulation that achieves full cement replacement through the use of fly ash, supplemented with nanocrystalline silica and glass fiber to enhance strength and setting dynamics. Eighteen sample sets were prepared for each composition, using consistent mixing, curing, and testing protocols. Mechanical strength was evaluated at multiple curing intervals alongside microstructural characterization using SEM and XRD. The results show that mixtures containing nanomodified silica and fiber exhibit significantly improved compressive, shear, and splitting strength—up to 40% higher than fly ash-only compositions. Microstructural analysis revealed accelerated C-S-H gel development, reduced porosity, and more uniform pore structures over time. These findings confirm the mechanical viability and economic potential of waste-based backfill systems. The proposed formulation enables safer underground operations, improved extraction efficiency, and reduced environmental impact—offering a scalable solution for modern coal mining. Full article