Advancing Open Science

The article presents a comparative analysis of mechanical properties of M8 threaded joints produced using three different methods, in rectangular nylon (PA 12) specimens manufactured in SLS technology. Threaded holes in specimens were made by direct thread printing (specimens marked PT), thread reinforcement with Helicoil inserts (HT), and the use of heat-set inserts (IT). The specimens were subjected to a tensile testing at a constant displacement rate of 2 mm/min. The maximum force and the displacement at failure were recorded. The results indicated that the lowest load-bearing capacity F_MF was observed in the printed thread specimens, with an average value of 3.41 kN. The use of heat-set inserts increased F_MF to 3.83 kN, representing a 12% improvement. The highest load-bearing capacity was achieved in specimens reinforced with Helicoil inserts, which enhanced joint strength by 40% compared to printed thread specimens, reaching an average F_MF of 4.78 kN. In all cases, failure occurred due to the thread or insert pull-out from the specimen material. Studies have shown that the use of metal inserts significantly enhances the strength of threaded joints in SLS-printed PA12 components. Helicoil inserts provide the highest F_MF load capacity, while heat-set inserts offer better technological advantages. Although printed threads are easier to manufacture, their applicability is limited to larger thread sizes and lower mechanical loads.

Printing with high-performance polymers such as polyether ether ketone (PEEK) and polyetherimide (PEI) presents issues regarding shrinkage and warpage due to elevated temperatures. One method highlighted to mitigate against this is through polymer blending. This study explores the development and characterization of PEEK and PEI blends as filament for fused filament fabrication (FFF) in additive manufacturing. Filaments were produced via melt extrusion using PEEK/PEI weight ratios 100/0, 80/20, 70/30, 60/40, 50/50, 40/60, 20/80, and 0/100 (wt.%). The aim is to identify an optimum blend which enhances printability and maintains mechanical and thermal integrity. The extruded filaments were first characterized through differential scanning calorimetry (DSC) to determine miscibility with all ratios presenting a single glass transition temperature. Samples were then 3D-printed and assessed through mechanical testing, DSC, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The PEEK/PEI 80/20 (wt.%) blend was recognized as the optimum blend for maintaining crystallinity (35%) as well as good mechanical properties, averaging ultimate tensile strengths (UTSs) of 75.6 MPa and a Young’s modulus of 1338 MPa. Thermal properties also improved while warpage reduced and printability improved.

Evaluating the effect of recycling Pesticide Packaging Waste (PPW) is essential for improving recycling rates, which plays a crucial role in controlling environmental pollution and optimizing the efficiency of agricultural resources worldwide. Based on the micro-survey data of 1223 farmers in Yunnan and Hainan provinces of China, this study measures the economic effect by the farmers’ annual total household income and the ecological effect by the ecological environment quality of villages. The propensity score matching method (PSM) is employed to empirically test the economic and ecological effects of farmers’ recycling behavior of PPW and their differences. The research findings are as follows: Farmers’ recycling of PPW can generate significant positive economic and ecological effects, which are 116.7% and 4%, respectively. The heterogeneity analysis shows that farmers with a low degree of land fragmentation have a more obvious economic effect from PPW recycling, while farmers with a higher degree of land fragmentation have a more significant ecological effect; farmers with high pesticide costs have more significant economic and ecological effects from PPW recycling. Based on these findings, it is suggested to increase the attention at the policy level, enhance farmers’ environmental awareness and capacity, and focus on the characteristics of different groups.

A male specimen of whitefly Pudrica christianottoi Drohojowska et Szwedo, 2024, of subfamily Aleyrodinae, previously known from the sole female specimen from Lower Lusatia succinite, is here described, based on an inclusion from Bitterfeld amber. This fossil is contributing new data to our understanding of morphological disparity, sexual dimorphism, taxonomic diversity and palaeobiogeographic distribution of the whiteflies in the Eocene fossil resins. It is also a contribution to the ongoing discussions on age, similarities, dissimilarities and taphonomic differences among Eocene resins of Europe collectively known as ‘Baltic amber’.

Biofouling on aquaculture netting increases hydrodynamic drag and restricts water exchange across net cages. The solidity ratio is introduced as a quantitative parameter to characterize fouling severity. Towing tank experiments and computational fluid dynamics (CFD) simulations were used to assess the hydrodynamic behavior of netting under different fouling conditions. Experimental results indicated a nonlinear increase in drag force with increasing solidity. At a flow velocity of 0.90 m/s, the drag force increased by 112.2%, 195.1%, and 295.7% for netting with solidity ratios of 0.445, 0.733, and 0.787, respectively, compared to clean netting (S_n = 0.211). The drag coefficient remained stable within 1.445–1.573 across Re of 995–2189. Numerical simulations demonstrated the evolution of flow fields around netting, including jet flow formation in mesh openings and reverse flow regions and vortex structures behind knots. Under high solidity (S_{n =}0.733–0.787), complex wake patterns such as dual-peak vortex streets appeared. Therefore, this study confirmed that the solidity ratio is an effective comprehensive parameter for evaluating biofouling effects, providing a theoretical basis for antifouling design and cleaning strategy development for aquaculture cages.

Background/Objectives: This study aimed to perform a comparative analysis of the original Viagra^® product and sildenafil-containing tablets obtained from illegal sources (the darknet). Specifically, the analyzed material consisted of samples seized by Polish law enforcement authorities from unverified vendors operating within the Central European darknet market. The study utilized thermal methods, specifically Thermogravimetry (TG), Derivative Thermogravimetry (DTG), and calculated Differential Thermal Analysis (c-DTA), as well as colorimetric analysis based on the International Commission on Illumination (CIE) L*a*b* system. Methods: Thermal analyses enabled the assessment of the thermal stability of the tested samples, identification of characteristic stages of thermal decomposition, and determination of differences in thermal behavior between the pure substance, the original preparation, and darknet samples. In turn, color measurements in the CIE L*a*b* space allowed for an objective comparison of tablet appearance and determination of the degree of color similarity to the original product. Results: The obtained results showed that only a few samples (V1, V3, V4, V6, V8) exhibited features similar to the original Viagra^®, both in terms of thermal profile and color. Most of the tested tablets were characterized by significant variability in physicochemical properties, indicating a lack of quality control and inconsistency in formulation. Samples V2 and V7 deviated particularly strongly—both thermally and visually—suggesting that they might not contain the original active substance or contained it in a different chemical form. Conclusions: The use of combined thermal and colorimetric methods proved to be an effective tool in the identification of counterfeit pharmaceutical products, enabling simultaneous evaluation of their composition and authenticity. The results confirm the validity of employing integrated physicochemical analyses for the detection of falsified medicines present on the illegal market.

The CoCrFeNiMn High-Entropy Alloy (HEA) with 0, 0.5 and 1.0 at.% Carbon (C) addition has been evaluated by mechanical and corrosion testing, including tensile, wear and corrosion resistance testings. The result shows that the medium of 0.5 at.% C addition into HEA brings higher tensile toughness with 27,213.6 MPa%, less wear damage (0.37 mm³) and superior thermodynamic stability (0.73 V_SCE), compared with that of the other two compositions. The tensile fracture observation points out that the high C addition embrittles the HEA with poorer toughness and wear resistance with content increasing to 1.0 at.%. The HEA material with 0.5 at.% C addition has high corrosion potential and the lowest corrosion current density, indicating that the appropriate C-alloying plays a significant role in determining the corrosion properties of HEA. The current study shall provide meaningful instruction for high-performance C-alloyed HEA development.

Background: Burnout among healthcare workers (HCWs) threatens workforce stability and patient care, particularly in rural hospitals where staff shortages, limited resources, and professional isolation amplify stress. Peer support interventions have demonstrated promise in urban centers, but their feasibility and impact in rural settings remain underexplored. Methods: We implemented and evaluated the Johns Hopkins RISE (Resilience in Stressful Events) peer support program across two rural hospital systems in the Mid-Atlantic United States. Using pre- and post-implementation surveys, we assessed anxiety (GAD-7), burnout (Maslach Burnout Inventory), resilience (CD-RISC), and perceptions of organizational culture of well-being. Linear and logistic regression models adjusted for age, site, and employment duration were used to evaluate outcomes over time. Results: A total of 868 respondents participated across three time points. Burnout and anxiety declined modestly post-implementation, while resilience improved initially but was not sustained at 2-year follow-up. Older employees demonstrated lower anxiety and burnout, while mid-career employees (3–10 years of employment) reported significantly higher distress. Importantly, access to peer support and perceived availability of supportive resources improved significantly over time, reflecting growing program integration. Conclusions: RISE was adapted successfully in rural hospital settings, with evidence of reduced burnout, lower anxiety, and increased perceived access to peer support. While resilience gains were not sustained, results suggest that a peer support program tailored to each organization can mitigate workforce distress in rural health systems. Addressing implementation and contextual barriers and sustaining organizational commitment are important for long-term impact. Expanding peer support to rural hospitals may improve workforce retention and care delivery in underserved communities.