Search Results (2,827)

Background: Male infertility affects millions of couples, accounting for 50 percent of cases. Despite such a major contribution of the male factor, it is not properly evaluated and is often overlooked in infertility assessments. Semen analysis, which is routinely performed to assess infertility status, is unable to assess the defects at the molecular level which are important to assess the fertilizing capacity of the sperm. This study aims to determine the utility of sperm function tests as biomarkers for male infertility in addition to standard semen analysis. Methods: Thirty-five men (aged 25–45 years) were recruited and divided into two groups: those with at least one altered semen parameter (infertile group) and those with normal semen parameters but unable to conceive after more than one year of unprotected intercourse (unexplained male infertility group). The DNA Fragmentation Index (DFI), Nuclear Chromatin Decondensation Test (NCDT) and Hypoosmotic Swelling Test (HOS) were used in diagnosing sperm dysfunction in both groups. The Mann–Whitney U testand Spearman’s rank correlation were used for analyzing the parameters of the groups. A p value < 0.05 was considered statistically significant. Results: While motility and vitality were nearly identical in both groups, the infertile group showed more morphological abnormalities. The DFI was higher in the unexplained male infertility group (UMI) (82%) than in the infertile group (36%). Poor decondensation capacity was present in 27% of the unexplained male infertility group and 60% of the infertile group. Both groups’ hypoosmotic swelling values fell within the usual range. Spearman correlation analysis revealed that the NCDT showed significant positive correlations with sperm vitality (r = 0.36; p = 0.02) and morphology (r = 0.53; p = 0.001). The DFI demonstrated significant negative correlations with vitality (r = −0.45; p = 0.006) and motility (r = −0.39; p = 0.01). HOS was significantly positively correlated with motility (r = 0.56; p = 0.0004) and vitality (r = 0.57; p = 0.0003). Additionally, the NCDT and DFI showed a significant inverse correlation (r = −0.33; p = 0.04). Conclusions: These findings highlight the potential of sperm function tests as valuable diagnostic tools alongside conventional semen analysis for a more comprehensive assessment of male fertility. Full article

Raman spectroscopy (SERS) has emerged as a powerful analytical technique, offering molecular fingerprint specificity and ultrasensitive detection of cardiac biomarkers. Recent advances in plasmonic nanostructures, surface functionalization strategies, and flexible sensing platforms have significantly improved the analytical performance of SERS-based biosensors. In parallel, the integration of artificial intelligence (AI) and machine learning has enabled robust interpretation of complex spectral datasets, facilitating automated biomarker classification and improved diagnostic accuracy in heterogeneous biological environments. Despite these advances, the field remains fragmented, with limited integration between nanomaterial design, biomarker selection, and data-driven analysis, and persistent challenges related to reproducibility, standardization, and clinical validation. This review provides a comprehensive and critical synthesis of AI-assisted SERS platforms for cardiovascular diagnostics, integrating advances in plasmonic materials, biomolecular recognition, and intelligent spectral analysis within a unified framework. It further examines key translational barriers, including data variability, model interpretability, and scalability, and outlines future directions for developing standardized, edge-deployable, and clinically validated SERS-AI systems. Full article

This work investigates a novel GaCl₃·AlCl₃/H₂O catalytic system for the synthesis of low-molecular weight polyisobutylene (LPIB). Catalytic performance was improved by employing a dual Lewis acid system, which outperformed the conventional single component (GaCl₃/H₂O) catalyst in terms of both reaction rate and yield. In accordance with the optimized reaction conditions, the conversion of monomer was found to be 97%, thereby achieving low molecular weight polyisobutylene (LPIB) with a number average molecular weight (M_n) of 3900 g/mol. Density functional theory (DFT) calculations revealed a lower proton transfer barrier (5.8 kcal/mol) in the dual Lewis acid catalytic structure compared to its single component counterpart. Subsequent theoretical analyses, incorporating electrostatic potential (ESP), independent gradient model based on Hirshfeld partition (IGMH), and distortion/interaction analysis, attributed this observed kinetic advantage to a higher positive ESP extremum and enhanced interaction between the IB fragment and the Lewis-acidic active center. Together, these results establish the GaCl₃·AlCl₃/H₂O dual Lewis acid system as an enhanced catalytic platform over the conventional GaCl₃/H₂O system for efficient IB polymerization toward LPIB synthesis. Full article

Background/Objectives: First-generation CDK4/6 inhibitors (palbociclib, ribociclib, abemaciclib) target the conserved ATP-binding pocket of CDK4 and, despite clinical success, are limited by acquired resistance and insufficient exploration of alternative regulatory sites. This study aimed to identify a putative allosteric small-molecule candidate at the CDK4 αE-helix–Cyclin D1 α1-helix protein–protein interaction (PPI) interface within the CDK4/Cyclin D1/p21 ternary complex using RapidFunnel-AI, a decision-interpretable virtual-screening pipeline. Methods: Starting from 50,000 ChEMBL 33 molecules, the pipeline sequentially applied a Q-Fold/RapidFunnel topological Tanimoto scan based on clinical CDK4/6 inhibitor motifs, fragment-level electronic-property enrichment, ADMET/PAINS filtering, dry Vina-GPU docking, hydration-mediated AutoDock-GPU (Version 1.6) docking, explicit-solvent molecular dynamics, contact-retention analysis, and MM-GBSA energy decomposition. The Q-Fold Thermo-Core surrogate model provided fragment-level enrichment, predicting the HOMO–LUMO gap (R² = 0.93) and isotropic polarizability (R² = 0.98) on QM9. Candidate selection did not rely on the lowest docking or MM-GBSA score alone, but on pose persistence, contact continuity, and energy-component consistency. Results: The workflow reduced the initial library to 43 topologically prioritized candidates, 25 ADMET/PAINS-filtered ligands, and 9 docking-derived complexes for MD validation. Ligand_020 emerged as the only candidate that preserved a persistent binding mode at Site 2 during a 500 ns simulation—an interface engagement reproduced across three independent 500 ns replicates with no full dissociation in any replicate—with a protein Cα RMSD of 2.88 ± 0.32 Å, a ligand heavy-atom RMSD of 3.56 ± 0.28 Å, and a van der Waals-dominated MM-GBSA profile (ΔGbind = −28.23 ± 3.57 kcal/mol). In contrast, palbociclib and ribociclib, forcibly placed at Site 2 as negative controls, lost most initial contacts within 5 ns and tended to detach despite more favorable MM-GBSA values. Conclusions: These results suggest that single-score docking or MM-GBSA ranking can generate false positives at shallow PPI interfaces. By integrating AI-assisted prioritization, multipocket docking, explicit-solvent MD, contact-retention analysis, and energy-component consistency, RapidFunnel-AI nominated Ligand_020 as an experimentally testable putative allosteric hit targeting the CDK4/Cyclin D1 interface, offering a reusable platform for PPI-focused oncological drug discovery. Full article

In this study, we conducted a molecular investigation of hemotropic Mycoplasma spp. in bat species captured in the northern region of the Pantanal biome, Mato Grosso State, Brazil. Tissue samples were screened by qPCR targeting the 16S rRNA gene. Positive samples were subsequently subjected to conventional PCR assays targeting partial fragments of the 16S rRNA (~900 bp) and 23S rRNA (~800 bp) genes. Hemoplasma DNA was detected in four bat species: Glossophaga soricina, Molossops temminckii, Molossus rufus, and Desmodus rotundus. Phylogenetic analyses based on partial 16S and 23S rRNA gene sequences demonstrated that the detected hemoplasmas clustered predominantly with previously described bat-associated hemoplasmas from Brazil and other countries in the Americas. Notably, the detection in M. temminckii represents, to our knowledge, the first molecular evidence of hemotropic Mycoplasma infection in this bat species. These findings expand current knowledge regarding the occurrence, host range, and genetic diversity of hemotropic Mycoplasma spp. in bats from the Pantanal biome and contribute to wildlife surveillance efforts in this ecologically important region. Full article

In the Iberian Peninsula, the rapid expansion of the invasive species Alburnus alburnus (bleak) has intensified its contact with several endemic cyprinid species, raising concerns about hybridization, introgression, and the loss of genetic diversity. Despite increasing evidence of hybridization, data remain limited for many Iberian River basins, where endemic species persist in fragmented and vulnerable habitats. The aim of this study is to assess the extent and spatial distribution of hybridization between the bleak and the following native cyprinid species, Anaecypris hispanica (jarabugo), Iberochondrostoma lemmingii (pardilla), Pseudochondrostoma willkommii (Guadiana nase), and Squalius alburnoides (calandino), across several rivers within the Guadalquivir Basin. To this end, Sanger sequencing will be performed on the mitochondrial cytochrome b gene (maternal lineage; approximately 1000 base pairs (bp)) and the nuclear β-actin gene (paternal lineage; approximately 950 bp) from individuals of all endemic species and the bleak. Parental species and putative hybrids were initially identified in the field using diagnostic morphological and meristic characters, including number of rays in the anal fin morphology, mouth position, and the number of lateral line scales. Molecular analyses will include haplotype network reconstruction and phylogenetic tree inference to evaluate relationships among individuals from different species and to assess lineage divergence. The results will allow us to: (1) detect hybrids between the bleak and endemic cyprinids, (2) identify hybridization events among endemic cyprinid species, and (3) evaluate the correspondence between diagnostic morphological and meristic traits and the molecular identification of hybrid individuals. Overall, these findings will provide key information for the conservation management of endangered Iberian freshwater fishes in the context of invasive species expansion and global change. Full article

Background: Benzimidazole (BZ) resistance in the gastrointestinal nematode Haemonchus contortus is a major constraint to sheep production worldwide. However, data on the prevalence and molecular mechanisms of resistance in Yili Prefecture, Xinjiang—a key livestock region in Northwestern China—remain limited. This study aimed to determine the frequency of BZ resistance-associated single nucleotide polymorphisms (SNPs) in H. contortus populations from Zhaosu and Tekesi counties. Methods: Adult male worms (n = 150) were collected from naturally infected sheep at local abattoirs. Species identity was confirmed morphologically by sequencing the internal transcribed spacer 2 (ITS-2) region. A 385 bp fragment of the isotype-1 β-tubulin gene was amplified and sequenced to detect SNPs at codons 167 (F167Y), 198 (E198A), and 200 (F200Y). Results: The F167Y mutation was absent in all individuals. In contrast, the E198A mutation occurred at exceptionally high frequencies, with resistant allele frequencies (RAF) of 64.7% in Zhaosu and 52.7% in Tekesi. The F200Y mutation showed clear geographical variation: it remained low in Zhaosu (RAF = 9.3%) but was substantially higher in Tekesi (RAF = 33.3%). Haplotype analysis revealed that resistance in Zhaosu was driven primarily by the E198A mutation, whereas the Tekesi population exhibited complex patterns of co-selection of both E198A and F200Y, with a high proportion of double-heterozygous individuals (29.3%). Conclusions: This study provides comprehensive molecular evidence of severe BZ resistance in H. contortus populations from Zhaosu and Tekesi counties, Yili Prefecture. The marked predominance of the E198A mutation, together with the emergence of multi-locus resistance in Tekesi, indicates a rapid escalation of resistance beyond historical levels. These findings suggest that benzimidazoles are likely ineffective in this region and highlight the urgent need to revise local parasite control strategies. Full article

The rapid expansion of molecular point-of-care (POC) diagnostics into decentralized settings, including emergency departments, retail pharmacies, and home environments, has shifted the burden of diagnostic performance from laboratory professionals to heterogeneous, often non-expert users. While traditional evaluation frameworks focus on analytical and clinical validity, they often overlook the impact of human-system interactions on real-world reliability. This review introduces the concept of Operational Validity: the ability of a diagnostic system to preserve its intended performance when operated by intended users within the constraints of real-world workflows and environments. To establish a rigorous foundation for this concept, this study provides a critical comparative analysis contrasting Operational Validity against traditional clinical evaluation dimensions (analytical validity, clinical validity, and clinical utility) and post-market metrics. While existing literature outlines isolated usability principles, the significance of this study lies in its synthesis of these fragmented concepts into a formalized, lifecycle-based “Operational Validity” framework that explicitly maps the causal mechanisms connecting initial user interaction directly to downstream clinical outcomes. By synthesizing international standards (IEC 62366-1) alongside the newly finalized May 2026 U.S. Food and Drug Administration (FDA) guidance on the Content of Human Factors Information in Medical Device Marketing Submissions, we examine how human factors engineering (HFE) and usability engineering serve as the methodological foundation for operational validity. We analyze the specific complexities of molecular workflows, identify key parameters of use-related failure modes in pre-analytical and interpretation stages, and detail the mandatory role of iterative formative and final summative usability testing in mitigating these risks. Finally, we propose a lifecycle-based approach to HFE that integrates design, simulated-use validation, and post-market surveillance. Establishing operational validity is essential to ensure that the high analytical sensitivity of molecular POC platforms translates into consistent clinical utility across the full spectrum of decentralized care. Full article

Colorectal cancer is the third most commonly diagnosed cancer worldwide and the second leading cause of cancer-related deaths, while its resistance to treatment continues to represent a major therapeutic challenge. In the present study, a series of phenothiazine derivatives, including hybrids containing a 1,2,3-triazole linker and the zidovudine (AZT) fragment, were synthesized and evaluated for their anticancer activity against colorectal cancer cell lines HCT116 and HT-29 as well as non-cancerous BEAS-2B cells. Cytotoxic activity was determined using the Alamar Blue assay, while the mechanisms of action were investigated by flow cytometric analysis of apoptosis, cell cycle progression, and reactive oxygen species (ROS) generation. Additionally, changes in the expression of genes associated with apoptosis, oxidative stress, and DNA damage response were analyzed by RT-qPCR. The obtained results demonstrated that AZT-containing derivatives exhibited stronger anticancer activity than non-conjugated phenothiazine analogs. Compounds A9–A12 induced pronounced apoptosis and significant disturbances in cell cycle progression, particularly in HCT116 cells. Among the analyzed derivatives, compound A9 displayed the most favorable overall biological profile, combining strong proapoptotic and cytotoxic activity with relatively high selectivity toward cancer cells and moderate effects on non-cancerous cells. The results indicate that molecular hybridization of phenothiazine derivatives with the AZT scaffold represents a promising strategy for the development of novel anticancer agents targeting colorectal cancer. Full article

Ganoderma lucidum spores protein (GLSP) holds significant potential for providing antioxidant peptides. We employed in silico enzymatic hydrolysis to generate small peptide fragments by specific proteins. Through fast computer screening and molecular docking with Keap1 receptor, we identified two potential antioxidant peptides, KAF (Lys-Ala-Phe) and NDSF (Asn-Asp-Ser-Phe), from 1171 candidates after efficient hydrolysis by pepsin and proteinase K. Molecular docking result showed both of them could bind onto the Leu557, Ala 510 and Val512 of bioactive pockets of Keap1 through hydrogen bonds and NDSF had lower docking energy (−85.6073 kcal/mol). The in vitro antioxidant validation indicated both of them could eliminate DPPH and ABTS radicals dramatically, and NDSF had a stronger scavenging capacity on DPPH (IC₅₀ = 35.1 μg/mL) and ABTS (IC₅₀ = 55.9 μg/mL), respectively. Quantitative chemical analysis further revealed that the key antioxidant active sites of NDSF were located at O18 of Ser amino side chain, and N9 of Lys terminal amino residue for KAF. Furthermore, in the cellular experiments, NDSF and KAF effectively increased the activities of antioxidant enzymes such as SOD, CAT, and GPx, while also reducing the level of MDA. Together, these findings highlight the potential of Ganoderma lucidum spore proteins as a source for the rapid identification of antioxidant peptides. The two selected peptides, therefore, s hold promising prospects for applications in functional foods and health products. Full article

Heat stress severely constrains wheat productivity, yet the mechanisms underlying thermotolerance remain incompletely understood. This study integrated physiological, biochemical, molecular, and ultrastructural analyses to characterize heat-stress responses in four bread wheat (Triticum aestivum L.) genotypes contrasting in heat tolerance. Membrane injury was assessed by membrane damage rate, lipid peroxidation by malondialdehyde accumulation, antioxidant defense by SOD, CAT, GPX, and BPX activities, and stress-responsive regulation by qRT-PCR analysis of DREB, HSP16.9, and SOD isoforms. HSP16.9 protein accumulation was further evaluated by Western blotting. Heat stress increased membrane damage and MDA accumulation in all genotypes; however, tolerant Murov 2 and Zirva 85 showed lower oxidative membrane injury than sensitive Aran and Gyzyl bugda. Thermotolerance was associated with stronger antioxidant activation, enhanced DREB and HSP16.9 induction, and more coordinated FeSOD and MnSOD expression. The HSP16.9 protein accumulated after heat treatment, supporting its role as a stress-responsive molecular chaperone. Separate correlation analyses of tolerant and sensitive genotypes revealed stronger coordination among transcriptional, chaperone-related, and antioxidant markers in tolerant genotypes, whereas sensitive genotypes showed a more fragmented response. Microscopy further showed better preservation of chloroplast, mitochondrial, and mesophyll organization in the tolerant genotype relative to the sensitive counterpart, indicating integrated cellular protection. Together, these responses define a coordinated tolerance strategy that may guide the selection of heat-resilient wheat genotypes. Full article

The pyrolysis of polypropylene (PP) microplastics offers a potential route to convert plastic waste into fuel-range hydrocarbon mixtures and chemical feedstocks. However, the elementary radical pathways underlying the formation of medium-chain hydrocarbon fragments remain insufficiently resolved. In this study, a representative isotactic PP oligomer model (C₄₅H₉₂) was evaluated using a comparative density functional theory (DFT) framework. The main mechanistic analysis was based on M06-2X, ωB97X-D, and M11 calculations combined with the def2-TZVP basis set, whereas LANL2DZ was retained only as a lower-cost comparative level during reaction-pathway exploration. Thermochemical profiles were evaluated over a temperature range of 298–923 K. Three selected pathways involving mid-chain homolytic cleavage, intramolecular hydrogen transfer (backbiting), radical rearrangement, and β-scission were examined. Within the selected reaction set, Route 1 exhibited a comparatively more favorable thermochemical profile than Routes 2 and 3 and provided a mechanistically plausible sequence toward medium-chain hydrocarbon fragments. The −TΔS contribution strongly influenced the calculated Gibbs free-energy profiles because fragmentation increases the number of molecular species under the ideal-gas thermochemical approximation. Accordingly, the ΔG values were interpreted comparatively and were not treated as direct evidence of spontaneous fragmentation under condensed-phase pyrolysis conditions or as quantitative predictions of experimental product selectivity. Differences among the evaluated functionals further indicate that the relative description of radical intermediates and transition-state regions is method-dependent. These results provide a molecular-level framework for future studies integrating quantum-chemical calculations, microkinetic modeling, and experimental product characterization. Full article

This study evaluates the microbiological quality of drinking water in the urban area of Guaranda through an integrated approach combining culture-based methods, biochemical characterization, and polymerase chain reaction (PCR) analysis. A total of 50 drinking water samples were collected from strategically selected points within the urban distribution system following Ecuadorian technical standards. Microbiological analyses included the detection of total and fecal coliforms, as well as the isolation and identification of Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes. Culture-based analyses revealed that 22% of samples were positive for total coliforms and 4% for fecal coliforms. In selective culture media, contamination rates reached 18% for E. coli O157:H7, 8% for Salmonella spp., and 46% for Listeria monocytogenes. However, biochemical profiling showed substantial inconsistencies with the expected phenotypic characteristics of these pathogens, particularly in oxidase and citrate tests, suggesting possible false-positive identifications in complex environmental matrices. PCR assays confirmed lower detection frequencies, identifying E. coli O157:H7 and Salmonella spp. in 2% of samples each, and Listeria monocytogenes in 10% of samples. Agarose gel electrophoresis validated the amplification of specific DNA fragments of 212 bp, 244 bp, and 388 bp, respectively. The findings demonstrate significant discrepancies between conventional phenotypic methods and molecular techniques, highlighting the limitations of culture-based identification when used alone. This study emphasizes the importance of integrating molecular diagnostics into routine water quality monitoring programs to improve the reliability of pathogen detection and support more effective public health risk management in urban drinking water systems. Full article

This study aimed to determine the prevalence and risk factors associated with Toxoplasma gondii infection in blood donors from the Brazilian Semiarid region, and to explore its implications for transfusion safety. Samples were collected from 646 donors at blood donation centers in the states of Ceará and Paraíba. Serological diagnosis was performed using BIOLISA TOXOPLASMOSE ELISA kits for anti-T. gondii IgM and IgG antibodies, and molecular diagnosis was conducted by conventional PCR targeting a 529-bp noncoding repetitive fragment. Epidemiological questionnaires on variables associated with infection were administered, and statistical analysis was performed in univariate and multivariate stages, using multiple logistic regression. Among the 646 donors, 43.4% (281/646) were positive for anti-T. gondii IgG antibodies, 0.3% (2/646) for IgM antibodies, and none tested positive by PCR. In the univariate analysis, age, family income, educational level, salad washing practices, water source, raw milk consumption, and duration as a donor were significantly associated, whereas in the multivariate analysis only “age” and “salad washing practices” remained significant. A substantial IgG seroprevalence was observed among blood donors in the Brazilian Semiarid. The low IgM frequency, concurrent IgG positivity, and negative PCR results are consistent with a low transfusion risk in the region. However, these findings should be interpreted cautiously, as negative PCR results do not completely rule out the presence of circulating parasites. Age was identified as a risk factor, whereas proper salad washing showed a protective effect. Full article

The aspidogastrean genus Lobatostoma Eckmann, 1932 remains poorly understood, with limited morphological and molecular data hindering its systematics and phylogenetic resolution. In the present study, we provide the first integrative characterisation of Lobatostoma anisotremum Oliva & Carvajal, 1984 from the southeastern Pacific coast of Peru, combining detailed morphological, ultrastructural and molecular analyses. A total of 137 specimens were recovered from the intestine of 65 Peruvian grunt, Anisotremus scapularis (Tschudi, 1846) (Haemulidae), with a prevalence of 43% and mean abundance of 2.1 ± 3.4 parasites per host. Morphological observations based on light microscopy and scanning electron microscopy (SEM) allowed the refinement of diagnostic features, including tegumental papillae distribution, marginal organs, and reproductive structures. Molecular characterisation included the generation of novel sequences for the 18S rDNA and 28S rDNA gene fragments, representing the first comprehensive molecular dataset for L. anisotremum. Phylogenetic analyses based on 18S and 28S rDNA datasets consistently recovered L. anisotremum as sister to L. manteri Rohde, 1973, with strong support in the 28S analysis. In contrast, L. kemostoma (MacCallum & MacCallum, 1913) was recovered as a distinct and independent lineage, clearly separated from other congeners, supporting previous hypotheses of non-monophyly within Lobatostoma. These findings could be further supported by consistent morphological differences, particularly in cephalic lobe configuration, hindbody length and number of alveoli on the ventral disc. Our results also suggest that current family- and subfamily level classifications within Aspidogastridae Looss, 1901 may not reflect evolutionary relationships, as evidenced by the nested position of Multicalycidae Gibson & Chinabut, 1984 and the apparent non-monophyly of traditionally defined subfamilies. Although our data supports the distinctiveness of certain lineages, including L. kemostoma, we refrain from proposing formal taxonomic changes due to limited taxon sampling and the need for a comprehensive revision of the group. Overall, this study highlights the importance of integrative approaches in resolving the systematics of Aspidogastrea Faust & Tang, 1936 and provides a robust framework for future taxonomic and phylogenetic studies. Full article