Search Results (247)

This study investigates the surface modification of Ti-6Al-4V alloy through the electrical discharge machining (EDM) process to improve its suitability for orthopedic and dental implant applications. The analysis focused on evaluating the morphological, wettability, roughness, hardness, and biocompatibility properties of the modified surfaces. Samples were subjected to different dielectric fluids and polarities during EDM. Subsequently, optical microscopy, roughness measurements, Vickers microhardness, contact angle tests, and in vitro cytotoxicity assays were performed. The results demonstrated that EDM processing led to the formation of distinct layers on the sample surfaces, with surface roughness increasing under negative polarity by up to ~304% in Ra and 305% in Rz. Additionally, wettability measurements indicated that the modified surfaces presented a lower water contact angle, which suggests enhanced hydrophilicity. Moreover, the modified samples showed a significant increase in Vickers microhardness, with the highest value reaching 1520 HV in the recast layer, indicating improvements in the mechanical properties. According to ISO 10993-5, all treated samples were classified as non-cytotoxic, presenting RGR values above 75%, similar to the untreated Ti-6Al-4V alloy. Therefore, it is concluded that surface modification through the EDM process has the potential to enhance the properties and safety of biomedical implants made with this alloy. Full article

The mechanisms by which rotation influences zonal flows (ZFs) in plasma are incompletely understood, presenting a significant challenge in the study of plasma dynamics. This research addresses this gap by investigating the role of non-inertial effects—specifically centrifugal and Coriolis forces—on Geodesic Acoustic Modes (GAMs) and ZFs in rotating tokamak plasmas. While previous studies have linked centrifugal convection to plasma toroidal rotation, they often overlook the Coriolis effects or inconsistently incorporate non-inertial terms into magneto-hydrodynamic (MHD) equations. In this work, we derive self-consistent drift-ordered two-fluid equations from the collisional Vlasov equation in a non-inertial frame, and we modify the Hermes cold ion code to simulate the impact of rotation on GAMs and ZFs. Our simulations reveal that toroidal rotation enhances ZF amplitude and GAM frequency, with Coriolis convection playing a critical role in GAM propagation and the global structure of ZFs. Analysis of simulation outcomes indicates that centrifugal drift drives parallel velocity growth, while Coriolis drift facilitates radial propagation of GAMs. This work may provide valuable insights into momentum transport and flow shear dynamics in tokamaks, with implications for turbulence suppression and confinement optimization. Full article

This study analyzes the comparative performance of ten hospitals in the Kadutu Health Zone in the Democratic Republic of Congo using the EGIPSS model. This study was carried out at the height of the COVID-19 pandemic in August and September 2021, in a changing global context where health systems were called upon to improve their resilience capacity while maintaining high levels of performance. This is a descriptive observational study using documentary review, interviews with 85 key informants, and participatory observation at ten hospitals selected based on several criteria, including the organization of a complete complementary package of activities assigned to a hospital in the DR Congo. This study mainly reveals three facts, namely that (i) university hospitals show the best performance, (ii) adaptive capacity considerably influences the other dimensions of the EGIPSS model and the overall performance of the hospital, and (iii) to adapt, hospitals need resources and good management and governance. Adapting hospitals in the Kadutu Health Zone to the changing context requires a holistic approach that combines clinical work with research, investments in infrastructure (often dilapidated and not modern), training, technology, and governance. It also involves learning from practices implemented in more efficient hospitals. Full article

Motivated by illuminating the underlying mechanisms of preeclampsia, we develop a changepoint detection-based general and versatile methodology that can be applied to any experimental model, effectively addressing the challenges of high uncertainty produced by experimental interventions, intrinsic high variability, and rapidly and abruptly varying time dynamics in perfusion signals. This methodology provides a systematic and reliable approach for robust perfusion signal analysis. The main innovation of our methodology is a highly efficient automatic data processing system consisting of modular programming components. These components include a signal processing tool for optimal segmentation of perfusion signals by isolating their “genuine” vascular response to experimental interventions, and a novel and suitable normalization to evaluate this response concerning an experimental reference state, typically basal or pre-intervention. In this way, we can identify anomalies in an experimental group compared to a control group by disaggregating noise during the transitions just after experimental interventions. We have successfully applied our general methodology to perfusion signals measured from a preeclampsia-like syndrome model developed by our research group. Our findings revealed impaired brain perfusion in offspring from preeclampsia, particularly dysfunctional brain perfusion signals with inadequate perfusion signal vasoreactivity to thermal physical stimuli. This general methodology represents a significant step towards a systematic, accurate, and reliable approach to robust perfusion signals analysis across various experimental settings with diverse intervention protocols. Full article

Tick-borne piroplasmids are apicomplexan protozoa that infect a wide range of vertebrate hosts, with significant implications for animal and human health. This study investigated the occurrence and genetic diversity of piroplasmids in wild mammals, unconventional pets, and associated ticks in Goiás state, midwestern Brazil. Between April 2023 and January 2024, 105 blood samples, 22 tissue samples, and 300 ticks were collected from 21 mammalian species housed in wildlife screening centers, zoos, and veterinary clinics. Molecular screening targeting the 18S rRNA gene of piroplasmids detected a 25.7% (27/105) overall positivity, with gray brockets (Subulo gouazoubira) and South American tapirs (Tapirus terrestris) showing the highest infection rates. Three tick samples tested positive, including two Amblyomma sculptum nymphs and a male of Amblyomma dubitatum collected from a tapir and capybara (Hydrochoerus hydrochaeris). Cytauxzoon brasiliensis was reported, for the first time, in cougars (Puma concolor) from Goiás state, midwestern Brazil, indicating the role of this feline as a host of this parasite. Babesia goianiaensis was confirmed in a capybara, and Theileria terrestris in tapirs. Phylogenetic analyses clustered gray brockets-associated Theileria sequences with Theileria sp. previously detected in Neotropical deer from Brazil and Theileria cervi. While the phylogenetic analysis of amino acid sequences of the cytochrome c oxidase subunit III separated Theileria genotypes detected in S. gouazoubira from T. cervi, hsp70-based phylogenetic inferences clustered the genotypes detected in Tapirus terrestris with Theileria terrestris, suggesting host-specific evolutionary lineages. These findings contribute to the understanding of Piroplasmida diversity and circulation in South American wild mammals, emphasizing the need for enhanced molecular surveillance to elucidate transmission dynamics, assess potential health risks, and contribute to the establishment of wildlife conservation and One Health strategies. Full article

Flax cultivation is influenced by geographical conditions and soil properties, affecting yield and fiber quality. This study examines the performance of two fiber flax varieties, Artemida and Hermes, in 2021–2023 in central–eastern Poland’s agroclimatic and soil conditions using a value chain approach. Field trials were conducted in soils of varying fertility under a continental climate, employing a randomized block design with four replications. Flax straw underwent dew-retting, and long fibers were extracted through laboratory scutching. Results showed significant differences between the varieties. Artemida achieved higher straw yields, particularly in moderately fertile soils, while Hermes produced a higher proportion of long fibers and adapted better to less-fertile soils. Hermes fibers were thinner and more delicate, whereas Artemida fibers were coarser and stronger. The average straw yield of the Artemida variety was higher by 1.5 t ha⁻¹ than that of the Hermes variety. The yield and quality of fiber were determined by soil fertility and climate, and the genotype–environment interaction was of the greatest importance. These findings provide valuable insights for farmers and stakeholders in selecting suitable flax varieties for different soil and climatic conditions in central–eastern Poland. The value chain approach also supports optimizing cultivation practices and improving the economic sustainability of flax production. Full article

Accurate estimation of hazelnut yield is crucial for optimizing resource management and harvest planning. Although the number of female flowers on a flowering plant is a reliable indicator of annual production, counting them remains difficult because of their extremely small size and inconspicuous shape and color. Currently, manual flower counting is the only available method, but it is time-consuming and prone to errors. In this study, a novel vision-based method for automatic flower counting specifically designed for hazelnut plants (Corylus avellana) exploiting a commercial high-resolution imaging system and an image-tiling strategy to enhance small-object detection is proposed. The method is designed to be fast and scalable, requiring less than 8 s per plant for processing, in contrast to 30–60 min typically required for manual counting by human operators. A dataset of 2000 labeled frames was used to train and evaluate multiple female hazelnut flower detection models. To improve the detection of small, low-contrast flowers, a modified YOLO11x architecture was introduced by adding a P2 layer, improving the preservation of fine-grained spatial information and resulting in a precision of 0.98 and a Mean Average Precision (mAP@50-95) of 0.89. The proposed method has been validated on images collected from hazelnut groves and compared with manual counting by four experienced operators in the field, demonstrating its ability to detect small, low-contrast flowers despite occlusions and varying lighting conditions. A regression-based bias correction was applied to compensate for systematic counting deviations, further improving accuracy and reducing the mean absolute percentage error to 27.44%, a value comparable to the variability observed in manual counting. The results indicate that the system can provide a scalable and efficient alternative to traditional female flower manual counting methods, offering an automated solution tailored to the unique challenges of hazelnut yield estimation. Full article

This study evaluated the repellent activity of DEET, eugenol, methyl eugenol, 1,8-cineole, and their combinations against Amblyomma sculptum nymphs through laboratory and field tests. Initially, the botanical compounds were tested individually in Petri dish assays to assess repellent activity over various intervals (1 min to 168 h) at concentrations of 2%. Eugenol and methyl eugenol exhibited the highest average repellent percentages (60 to 90%), with significant effects (p < 0.05) across most evaluation periods, in contrast to 1,8-cineole. Therefore, eugenol and methyl eugenol were selected for combination testing with DEET. The combinations of 7% DEET + 1% eugenol and 7% DEET + 2% methyl eugenol showed the best results, with average repellent efficacy exceeding 85%. The first combination was selected for field evaluation. In this test, volunteers wore treated socks and walked for two hours in a naturally infested area. A significant reduction (p < 0.05) in the number of ticks recovered from the socks was observed in the 7% DEET and 7% DEET + 1% eugenol treatments, with efficacies of 82.5% and 88.5%, respectively, after 120 min. Isolated eugenol showed limited field efficacy, with significant repellent activity (p < 0.05) lasting only 20 min. The results highlight the potential of eugenol and methyl eugenol as repellent compounds, especially when combined with DEET. The field study confirmed the efficacy of the 7% DEET + 1% eugenol. Full article

Background: Systematic reviewers face a growing body of biomedical literature, making early-stage article screening increasingly time-consuming. In this study, we assessed six large language models (LLMs)—OpenHermes, Flan T5, GPT-2, Claude 3 Haiku, GPT-3.5 Turbo, and GPT-4o—for their ability to identify randomized controlled trials (RCTs) in datasets of increasing difficulty. Methods: We first retrieved articles from PubMed and used all-mpnet-base-v2 to measure semantic similarity to known target RCTs, stratifying the collection into quartiles of descending relevance. Each LLM then received either verbose or concise prompts to classify articles as “Accepted” or “Rejected”. Results: Claude 3 Haiku, GPT-3.5 Turbo, and GPT-4o consistently achieved high recall, though their precision varied in the quartile with the highest similarity, where false positives increased. By contrast, smaller or older models struggled to balance sensitivity and specificity, with some over-including irrelevant studies or missing key articles. Importantly, multi-stage prompts did not guarantee performance gains for weaker models, whereas single-prompt approaches proved effective for advanced LLMs. Conclusions: These findings underscore that both model capability and prompt design strongly affect classification outcomes, suggesting that newer LLMs, if properly guided, can substantially expedite systematic reviews. Full article

Intertidal organisms experience daily environmental fluctuations, including changes in temperature, UV radiation, and aerial exposure during low tide, requiring physiological strategies for survival. One adaptation is the “preparation for oxidative stress” (POS), where antioxidants are upregulated preemptively to mitigate oxidative damage. While POS has been documented in over 120 species, in the case of intertidal species, most studies focus on single stressors under controlled-laboratory conditions. This study investigated POS in the sea urchin Echinometra lucunter under natural multi-stress conditions. Sampling occurred over a single day (from 5 a.m. to noon), analyzing three conditions: submerged (S), aerially exposed for 2 h (AE), and reimmersed for 2 h (R). There was a ~4 °C temperature increase in the AE group compared to the S group, with a peak of solar radiation during reoxygenation. Antioxidant enzyme activity—catalase, glutathione transferase (GST), and superoxide dismutase (SOD)—and lipid peroxidation (TBARS) were assessed in gonad and intestine tissues. GST activity increased by fourfold in the intestines of AE individuals, while TBARS was elevated in gonads, where no antioxidant upregulation happened. These results suggest that the POS-response (increase in GST) was triggered by the interaction of temperature and aerial exposure. This research emphasizes the critical importance of field studies in understanding complex, natural multi-stressor environments. Full article

Cowpea is a nutritionally and economically valuable legume, known for its adaptability to adverse conditions. However, water stress negatively affects its development, requiring technologies to enhance resilience. This study aimed to induce tolerance to water deficit in cowpea through seed priming with polyethylene glycol 6000 (PEG 6000) and silicic acid. A completely randomized experiment was conducted in a phytotron chamber with two water regimes (W50 and W100) and six seed priming treatments, with four replications. Priming consisted of three water potentials induced by PEG 6000 (0 MPa, −0.4 MPa, and −0.8 MPa) and two silicon concentrations (0 and 200 mg L⁻¹). Gas exchange parameters, including photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), intercellular CO₂ concentration (Ci), instantaneous water use efficiency (WUEi), and instantaneous carboxylation efficiency (iCE), were evaluated. Seed priming with PEG 6000 and silicon improved A, WUEi, and iCE under water deficit. Treatments 2 (0 MPa + 200 mg L⁻¹ Si), 3 (−0.4 MPa + 0 mg L⁻¹ Si), and 4 (−0.4 MPa + 200 mg L⁻¹ Si) enhanced gas exchange, suggesting an effective strategy for improving drought tolerance in cowpea and ensuring food security. Full article

Physical pretreatments play a crucial role in reducing the recalcitrance of lignocellulosic biomass, facilitating its conversion into fermentable sugars for bioenergy and chemical applications. This study critically reviews physical pretreatment approaches, including mechanical comminution, irradiation (ultrasound, microwave, gamma rays, and electron beam), extrusion, and pulsed electric field. The discussion covers the mechanisms of action, operational parameters, energy efficiency, scalability challenges, and associated costs. Methods such as ultrasound and microwave induce structural changes that enhance enzymatic accessibility, while extrusion combines thermal and mechanical forces to optimize hydrolysis. Mechanical comminution is most effective during short periods and when combined with other techniques to overcome limitations such as high energy consumption. Innovative approaches, such as pulsed electric fields, show significant potential but face challenges in large-scale implementation. This study provides technical and strategic insights into developing more effective physical pretreatments aligned with economic feasibility and industrial sustainability. Full article

The HERMES project investigates the utilization of surplus wind and solar energy to produce renewable fuels such as hydrogen, methane, and methanol for seasonal storage, thereby supporting carbon neutrality and the energy transition. This initiative aims to create a closed-loop, zero-emission energy system with efficiencies of up to 65%, employing a low-pressure (≤30 bar) synthesis process—specifically, sorption-enhanced methanol synthesis—integrated into the power system. Excess renewable electricity is harnessed for chemical synthesis, beginning with electrolysis to generate hydrogen, which is then converted into methanol using CO₂ sourced from a biogas plant. This methanol, biomethane, or a hybrid fuel blend powers a supercritical gas turbine, providing a flexible and reliable energy supply. Optimization analysis indicates that a combined wind and photovoltaic system can meet 62% of electricity demand, while the proposed storage system can handle over 90%. Remarkably, liquid methanol storage requires a compact 313 m³ tank, significantly smaller than storage requirements for hydrogen or methane in gas form. The project entails a total investment of 105 M EUR and annual operation and maintenance costs of 3.1 M EUR, with the levelized cost of electricity expected to decrease by 43% in the short term and 69% in the long term as future investment costs decline. Full article