Search Results (15,756)

The performance of proton exchange membrane fuel cells (PEMFCs) is greatly affected by their operating parameters, especially at high current densities. An advanced concentration loss model is proposed to improve a semi-empirical model describing PEMFC polarization, with the aim of accurate prediction at the whole current density interval from low to high levels. Experiments are designed to verify the improved semi-empirical model. Model comparison shows that the improved semi-empirical model has a better prediction accuracy and generalization ability than others. The effects of operating parameters and structural parameters on PEMFC performance are analyzed. The results indicate that a relatively high operating temperature, pressure, and gas diffusion layer (GDL) porosity can increase PEMFC performance. The influence of relative humidity and PEM thickness on PEMFC performance is different at low and high current densities. A relatively high humidity can improve PEMFC performance at a low current density, but PEMFC performance will be reduced if the relative humidity is too high at a high current density. A thinner PEM thickness can improve PEMFC performance at a low current density, but PEMFC performance does not necessarily improve with a decreasing PEM thickness at a high current density. Overall, the improved semi-empirical model realizes an accurate analysis of PEMFC performance from a low to high current density. Full article

Globally, the swine industry suffers significant economic losses due to the presence of porcine reproductive and respiratory syndrome virus (PRRSV). Unfortunately, existing vaccines fail to offer adequate protection against the various strains of PRRSV, and there are currently no specific treatments available for this virus. In this study, we screened four natural products and identified cinnamaldehyde (CA) as an effective inhibitor of PRRSV infection in Marc-145 cells. CA could achieve an inhibition rate of up to 93% on PRRSV N protein at 160 μM. Mechanistically, CA exerted anti-PRRSV ability in different treatment modes. CA could directly interact with PRRSV particles. Cinnamaldehyde blocks the binding, entry, replication, and release of PRRSV. Furthermore, a significant reduction in dsRNA levels was observed in the CA-treated groups compared to the control groups. In conclusion, our research demonstrated that CA could inhibit essential stages of the PRRSV lifecycle: binding, entry, replication, and release. CA could directly interact with PRRSV. Additionally, CA disrupted the expression of dsRNA during viral replication, thereby suppressing in vitro PRRSV replication in Marc-145 cells. This study provides crucial perspectives on the potential application of CA for the prevention and treatment of PRRS. Full article

This research investigates the production of galactomannan from Adenanthera pavonina L. in its crude form and its subsequent crosslinking with glutaraldehyde under various pH conditions. The study involved the creation of films and sponges from these materials, followed by a comprehensive analysis of their structural, thermal, swelling, and electrical properties. Galactomannan was crosslinked with a fixed concentration of 0.2 mol/L of glutaraldehyde, with pH levels ranging from 3 to 7. These films and sponges were prepared through a slow solvent evaporation process. The research encompassed multiple analytical techniques, including Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry, swelling profile assessments, and impedance spectroscopy. The findings from structural analysis indicated that variations in pH did not alter the amorphous nature of the samples but did influence the interactions between galactomannan molecules and restricted the mobility of polymeric chains, which resulted in different dielectric responses. Crosslinked samples exhibited reduced water solubility compared to unprocessed galactomannan. Crosslinking also decreases the ability of the material to polarize and align in response to the electric field, which justifies why crosslinked samples present a lower dielectric constant than the crude sample. Full article

Background: Most newly developed anticancer treatments trigger tumor cell death through apoptosis, for which involvement of caspases activity is essential. However, numerous mutations in apoptotic pathways that lead to cancer and favor resistance to apoptosis are known; most are related to caspase-dependent apoptosis pathways and thus have low efficacy. To overcome these limitations, we constructed a novel chimeric protein, GnRH-AIF, using a gonadotropin-releasing hormone (GnRH) analog as a targeting moiety and the apoptosis-inducing factor (AIF) in its cleaved form as a killing moiety, fused at the cDNA level. AIF has a crucial role in the caspase-independent apoptotic pathway. A wide variety of solid tumors overexpress GnRH-receptors (GnRH-R) that are targeted by the new GnRH-AIF chimeric protein. Methods and Results: In this study, we constructed, expressed, and highly purified GnRH-AIF chimeric proteins. We demonstrated the ability of the chimera to enter and specifically and very efficiently kill solid cancer cell lines overexpressing GnRH-R. Most importantly, upon its entry, GnRH-AIFs translocate to the nucleus where it causes DNA fragmentation leading to a direct caspase-independent apoptotic death. As AIFs lack nuclease activity, our findings also emphasize that cell death induced by GnRH-AIF is dependent on the presence of the ENDOG and PPIA proteins, known to participate in the formation of a DNA–degradosome complex. Finally, we demonstrated the high anti-tumor efficacy of the GnRH-AIF ex vivo, in a human, colon cancer organoid model. Conclusions: Our study shows the potential of using a GnRH-AIF chimeric protein as a novel approach to treat solid cancers that overexpress GnRH-R, via a caspase-independent apoptotic pathway. Full article

Water scarcity can negatively affect crop yield, posing a significant threat to global food security, such as drought. Plant growth-promoting rhizobacteria (PGPR), either as single strains or synthetic communities (SynComs), has shown promise in alleviating drought stress in various plant species. In this study, we examined the effects of water limitation on Salvia officinalis and the potential of a SynCom composed of five phosphate-solubilizing, auxin-producing, and/or nitrogen-fixing Gram-negative bacteria to enhance plant growth and drought tolerance. Plant growth, morphology, physiology, and leaf metabolomic profiles were assessed using a combination of physiological measurements and LC-MS untargeted metabolomics. Mild water stress induced a conservative water-use strategy in S. officinalis, characterized by increased root-to-shoot ratio and altered leaf morphology, without compromising photosynthetic performance. SynCom inoculation under well-watered conditions elicited drought-like responses, including transient reductions in stomatal conductance. Leaf metabolomic analysis revealed that inoculation influenced the abundance of several metabolites, including biogenic amines and dipeptides, under both irrigation regimes. Notably, drought stress and SynCom inoculation increased histamine and α-ketoglutaric acid levels, highlighting potential impacts on food quality. Under reduced irrigation, inoculation further modulated leaf morphology and biomass allocation, promoting thicker leaves and increased root biomass allocation. These results demonstrate the ability of the SynCom to modulate plant physiology and metabolism in response to both optimal and reduced irrigation, potentially enhancing drought resilience without directly improving growth. The study also highlights the complex interactions among microbial inoculation, plant stress responses, and leaf metabolite profiles, emphasizing the importance of considering the effects on the production of bioactive compounds when developing microbial inoculants for edible plants. Full article

Fungi such as Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans are opportunistic pathogens in humans. They usually infect individuals whose immune system is compromised due to either a primary infection, e.g., HIV/AIDS, or as part of treatment for another condition, e.g., stem cell or solid organ transplant. In hosts with a weakened immune system, these fungi can cause life-threatening infections. Unlike true pathogens, opportunistic pathogens do not have specific mechanisms to overcome a healthy host, requiring a different approach to understand how they cause infection. The ability of fungi to adapt to various environmental conditions, including the human host, is critical for virulence. In humans, micronutrient metals, such as iron, are sequestered to reduce serum concentrations, which helps to inhibit microbial growth. Other human tissues may increase metal concentrations to toxic levels to prevent infection by pathogens. The ability of fungi to acquire or detoxify nutrients, such as iron or copper, from the host is essential for the establishment of infection. In this review, the role of fungal nutrition will be discussed in relation to opportunistic fungal pathogens. It will focus on the acquisition of micronutrients, e.g., iron, copper, and zinc, and how this enables these fungi to circumvent host nutritional immunity. Full article

Despite the discovery of many chemotherapeutic drugs that prevent uncontrolled cell division processes, the development of compounds with higher anticancer efficacy and a lower level of side effects is an important task in modern pharmaceutical chemistry. Herein, a mild and convenient method for the preparation of N1-substituted 3-(1,2,3-triazolyl-methoxycarbonyl)coumarins or bis(coumarine-3-carboxylate)bis(triazole)alkandiyl by the copper(I)-catalyzed Huisgen cycloaddition reaction of readily available coumarin-3-carboxylic acid propynyl ester with azides or diazides has been presented. The synthesized compounds have been tested for their cytotoxicity on various cancer and noncancerous cell lines using the MTT assay. All new compounds were nontoxic on normal epithelial VERO cells. Two derivatives exhibited selectivity towards HPV-negative human cervical cancer cells, C33 A, with excellent activities in low concentrations (GI₅₀ 4.4–7.0 µM). In vitro mechanistic studies showed that bis(coumarine)bis(triazolylester) conjugate 3 induced time-dependent apoptosis in cervical cancer cell lines C33 A and CaSki, at the GI₅₀ concentration, as measured by Annexin V-FITC/PI staining. The most active coumarin–triazolyl ester conjugate 2g possessed anticancer activities, as indicated by its ability to induce S/G2 phase cell cycle arrest at a low concentration and early apoptosis in CaSki cells. The obtained results revealed the potential of new compounds as anticancer agents, particularly against cervical cancer. Full article

This study presents a machine learning approach for estimating the presence and extent of flange-face lubrication on a rail. It offers an alternative to the current empirical and subjective methods for lubrication assessment, in which track engineers’ periodic visual inspections are used to evaluate the condition of the rail. This alternative approach uses a laser-based optical sensing system developed by the Railway Technologies Laboratory (RTL) located at Virginia Tech in Blacksburg, VA, combined with a machine learning calibration model. The optical sensing system can capture the fluorescence emitted by the grease to identify its presence, while the machine learning model classifies the extent of grease present into four thickness indices (TIs), from 0 to 3, representing heavy (3), medium (2), light (1) and low/no (0) lubrication. Both laboratory and field tests are conducted, with the results demonstrating the ability of the system to differentiate lubrication levels and measure the presence or absence of grease and TI with an accuracy of 90%. Full article

Worldwide, cadmium (Cd) contamination severely threatens rice production and public health. Jasmonic acid (JA) is recognized to be involved in rice Cd stress responses, but the underlying mechanism remains unclear. In this study, we show that JA positively regulates Cd tolerance in rice by repressing Cd uptake and root-to-shoot translocation. Cd exposure rapidly elevated the endogenous JA in rice roots, which was associated with increased expression of JA synthesis and JA-responsive genes. Moreover, silencing the expression of either allene oxide synthase (OsAOS; active in JA biosynthesis) or CORONATINE INSENSITIVE1 (OsCOI1; active in JA perception) resulted in aggravated Cd toxicity and increased Cd accumulation in both the roots and shoots, as well as increased translocation from the root to the shoots. A short-term uptake experiment revealed that silencing of OsAOS and OsCOI1 enhanced root Cd uptake ability. Furthermore, the elevated transcript levels of genes for Cd uptake (OsNramp5, OsNramp1, and OsIRT1) and root-to-shoot translocation (OsHMA2) were observed in OsAOS and OsCOI1 RNAi plants in comparison with wild-type plants. Taken together, our findings suggest that JA enhances rice cadmium tolerance by suppressing Cd uptake and translocation. Full article

This study presents a full-system simulation methodology for MEMS, addressing the critical need for reliable performance prediction in microsystem design. While existing digital tools have been widely adopted in related fields, current approaches often remain fragmented and focused on specific aspects of device behavior. In contrast, our proposed framework conducts comprehensive device physics-level analysis by integrating mechanical, thermal and electrical modeling with process simulation. The methodology features a streamlined workflow that enables direct implementation of simulation results into fabrication processes. We model a MEMS gyroscope as an example to verify our simulation approach. Multiphysics coupling is considered to capture real-world device behavior, followed by quantitative assessment of manufacturing variations through virtual prototyping and experimental validation demonstrating the method’s accuracy and practicality. The proposed approach not only improves design efficiency but also provides a robust framework for MEMS gyroscope development. With its ability to predict device performance, this methodology is expected to become an essential tool in microsensor research and development. Full article

Total soluble solids (TSSs) serve as a crucial maturity indicator and quality determinant in apricots, influencing harvest timing and postharvest management decisions. This study develops an advanced framework integrating adaptive boosting (Adaboost) ensemble learning with high-frequency spectral variables selected by uninformative variable elimination (UVE) for the rapid non-destructive detection of fruit quality. Near-infrared (NIR) spectra (1000~2500 nm) were acquired and then preprocessed through robust principal component analysis (ROBPCA) for outlier detection combined with z-score normalization for spectral pretreatment. Subsequent data processes included three steps: (1) 100 continuous runs of UVE identified characteristic wavelengths, which were classified into three levels—high-frequency (≥90 times), medium-frequency (30–90 times), and low-frequency (≤30 times) subsets; (2) the development of the base optimal partial least squares regression (PLSR) models for each wavelength subset; and (3) the execution of adaptive weight optimization through the Adaboost ensemble algorithm. The experimental findings revealed the following: (1) The model established based on high-frequency wavelengths outperformed both full-spectrum model and full-characteristic wavelength model. (2) The optimized UVE-PLS-Adaboost model achieved the peak performance (R = 0.889, RMSEP = 1.267, MAE = 0.994). This research shows that the UVE-Adaboost fusion method enhances model prediction accuracy and generalization ability through multi-dimensional feature optimization and model weight allocation. The proposed framework enables the rapid, non-destructive detection of apricot TSSs and provides a reference for the quality evaluation of other fruits in agricultural applications. Full article

School leadership plays a critical role in shaping student academic performance. Despite the UAE’s recognition as one of the leading nations globally for quality education, research on the impact of leadership practices on performance in international assessments like PISA remains scarce. This study explores the influence of school leadership on students’ performance in the UAE’s schools. The PISA 2022 UAE database containing data on 24,600 15-year-old students across 840 schools was used to assess mathematical literacy based on their ability to apply math concepts and their attitudes toward the subject. Insights into leadership practices were utilized using responses from school principals in the PISA 2022 school leaders’ questionnaire. The results demonstrate that leadership practices significantly influence student outcomes. Schools where leaders emphasize teacher accountability and professional development show improved mathematics performance, lower anxiety levels, and enhanced self-efficacy among students. Conversely, excessive focus on disciplinary measures or teaching skill improvements is associated with reduced student self-efficacy. These findings highlight the importance of adaptive leadership approaches that consider local educational contexts, balancing accountability and support to optimize both student performance and well-being. By refining leadership practices, schools can drive meaningful improvements in student success and better equip learners to thrive in global educational benchmarks. Full article

Introduction: WELLfed is a community-based adult education programme focused on improving food literacy, with a stated aim to “nourish communities through food and connections”, in a low-income community in Aotearoa New Zealand. Adult learners are taught food preparation and cooking skills in weekly interactive sessions. Here, we describe two pilot phases of a three-phase evaluation. Methods: Our overall aim is to evaluate the effectiveness of the WELLfed programme. Phase 1, in keeping with the co-design approach of WELLfed, co-designed outcome measures through five focus groups (n = 20) involving a wide range of stakeholders. Phase 2 developed and refined a survey based on these co-designed measures. The survey was administered to WELLfed learners at baseline (n = 15) and again towards the end of their programme (follow-up n = 12). Wilcoxon rank sum tests of significance were performed, restricted to participants with both baseline and follow-up data. Results: Five domains of importance identified in Phase 1 were as follows: (i) engagement support, (ii) food knowledge and skills, (iii) personal development, (iv) relationship transformation, and (v) community flourishing. Phase 2 findings include increased comfort level at engagement (p = 0.063). Food knowledge and preparation skills improved on a range of factors. All metrics of self-confidence and self-efficacy increased, with the greatest change being the ability to find support in times of crisis. Self-reported excellent or very good health increased (p = 0.050). Fewer people reported food running out due to a lack of money (p = 0.016) or eating less because of a lack of money (p = 0.008). Conclusions: The pilot study shows the effectiveness of the WELLfed programme for improving food knowledge and skills, reducing food insecurity, and improving health outcomes. Further research with a larger sample size is required to confirm these pilot results. Full article

Nitrogen donor-based ligands are highly promising extractants for palladium separation from high-level liquid waste (HLLW). However, the electronic effect of these ligands, a critical factor influencing their complexation ability with Pd(II), remains largely unexplored. Herein, three picolinamide-based ligands were designed and synthesized, each featuring substituents with distinct electronic effects at the para-position of the pyridine (electro-donating methoxyl group for L-I, hydrogen for L-II, and electro-withdrawing ester group for L-III). The concurrent processes of Pd(II) coordination and ligand protonation enable the manipulation of pyridine nitrogen electronegativity, resulting in a tunable Pd(II) extraction performance. Notably, L-I exhibits the highest extraction efficiency at low acidities (≤1 M HNO₃) but the lowest extraction at high acidities (≥3 M HNO₃), whereas L-III shows the poorest efficiency at low acidities but the best performance at high acidities. The Job plot analysis and ESI-HRMS results reveal a 1:1 and 2:1 (L/Pd) stoichiometry in the Pd(II) complexation process. The single crystal X-ray analysis of Pd(NO₃)₂(L-II)₂ complex confirms a four-coordinated Pd(II) center, with two pyridine nitrogen atoms and two monodentate nitrate oxygens forming a quadrangular geometry. Density functional theory (DFT) calculations further indicate that the formation of 2:1 (L/Pd) complexes is energetically favored, and the stronger basicity of the nitrogen atoms correlates with a higher Pd(II) binding affinity and increased susceptibility to protonation. Full article

Background/objectives: Sarcopenia and sarcopenic obesity (SO) are related to an increased risk of adverse outcomes. The objective of this study was to assess the internal and clinical validation of the Spanish version of the SARC-Global questionnaire, a sarcopenia risk screening tool, and its ability to detect sarcopenia, severe sarcopenia, and SO in adults aged ≥ 60 years. Methods: A total of 167 participants (73.22 ± 6.70 years, 71.26% women) completed the study. First, reliability was assessed by the inter-rater and the test–retest analyses. For the clinical validation, the risk of sarcopenia (SARC-Global) was compared to sarcopenia diagnosed using three operational definitions. The SARC-Global’s ability to detect severe sarcopenia (SS) and sarcopenic obesity assessed with body mass index (SO-BMI) and body fat percentage (SO-BFP), considering nutritional status and physical activity level, was also analyzed. Results: The Spanish SARC-Global questionnaire showed a substantial to excellent inter-rater and test–retest reliability. Regarding the clinical validation, sensitivity/specificity values to detect cases of sarcopenia were 85.71%/64.38% (EWGSOP2), 83.33%/65.81% (FNIH), and 54.55%/63.46% (AWGS-2019). Diagnostic accuracy ranged from 67.07% (FNIH) to 62.87% (AWGS-2019). The analysis also indicated that SARC-Global cutoff of 13.5 was the optimal score for severe sarcopenia (100.00% sensitivity and 80.49% specificity), SO-BMI (100% sensitivity and 80.49% specificity), and SO-PBF (80.00% sensitivity and 80.86% specificity). Conclusions: The Spanish version of the SARC-Global questionnaire is a reliable and clinically valid instrument for identifying people at the risk of sarcopenia, severe sarcopenia, and sarcopenic obesity in Spanish older adults. Full article