Search Results (961)

In this study, chemiluminescence (CL) is presented as a highly sensitive, mechanistically coupled method for investigating the thermo-oxidative aging of dammar resin, a triterpenoid natural resin of central relevance to conservation science. In contrast to conventional spectroscopic techniques, CL does not primarily reflect the accumulated oxidation state; instead, it selectively detects the formation and decomposition of reactive peroxide and hydroperoxide intermediates, thereby providing an early view of the oxidative reactivity of the material. Measurements performed under inert and oxidative atmospheres provide a clear distinction between pre-existing oxidative damage and ongoing autoxidation. Correlation with Fourier-transform infrared (FTIR) spectroscopy demonstrates that oxidized functional groups are not necessarily associated with high oxidative reactivity, underscoring the functional advantage of chemiluminescence for stability assessment. The combination of dynamic CL measurements with model-free isoconversional kinetics has been shown to reveal the pronounced dependence of effective activation energy on the extent of the reaction. This α-dependence confirms the multistep nature of dammar oxidation and highlights the limitations of classical Arrhenius models. Furthermore, chemiluminescence is an effective screening tool for evaluating stabilizers and synergistic additive combinations, providing a robust basis for kinetic modeling and evidence-based decision-making in conservation science. Full article

Nitrate (NO₃⁻) serves as a pivotal molecule with dual functions in nutrient supply and signaling during plant growth and development. Precise monitoring of its spatiotemporal dynamics in planta is therefore essential for dissecting the regulatory mechanisms underlying plant nitrogen metabolism. However, conventional nitrate detection methods suffer from inherent limitations, including destructive sampling, insufficient spatiotemporal resolution, and an inability to achieve real-time whole-plant monitoring. Here, we report a genetically encoded nitrate biosensor, designated NitNRCL1, constructed using a split firefly luciferase complementation system. Functional validation in both prokaryotic and eukaryotic systems demonstrates that NitNRCL1 responds to changes in nitrate availability and generates stable chemiluminescent signals in bacteria and diverse plant species. Importantly, NitNRCL1 enables non-invasive, real-time, and whole-plant monitoring of nitrate levels in living plants. Using NitNRCL1, we successfully imaged the spatiotemporal dynamics of nitrate signaling in Arabidopsis thaliana. Collectively, our findings establish NitNRCL1 as a robust and novel tool for investigating nitrate transport, signaling, and metabolic pathways in plants. This biosensor advances our mechanistic understanding of plant nitrate biology and provides a technical foundation for breeding nitrogen-use-efficient crops and developing precision fertilization strategies. Full article

Background: Elevated anticardiolipin IgG (aCL IgG) has been reported in end-stage renal disease (ESRD), but its association with specific etiologies of kidney failure remains unexplored. The unique pathophysiology of diabetic–hypertensive nephropathy may be associated with a microenvironment that could potentially contribute to antiphospholipid antibody production and thrombotic complications. This study aimed to investigate whether aCL IgG elevation in hemodialysis (HD) patients is associated with combined diabetes–hypertension (DM + HTN) etiology and thrombocytopenia, thereby identifying a clinically distinct potential high-risk subgroup. In this hypothesis-generating study, we focused on within-HD patient comparisons rather than healthy controls. Methods: We enrolled 242 participants: 150 healthy controls (included only to establish local reference ranges) and 92 patients with maintenance HD. The study was conducted from 01 September to 20 November 2025 in Madinah, Saudi Arabia. Serum aCL IgG was measured by chemiluminescence immunoassay (positive ≥ 12 GPL units). Comprehensive hematological and biochemical parameters were analyzed. Multivariable logistic regression identified predictors of aCL positivity. Results: In the HD cohort, 21% demonstrated aCL positivity; this represents a substantially higher rate than the 2% observed in local healthy controls (p < 0.001). This elevation was not uniform across etiologies. Strikingly, 94.7% (18/19) of aCL-positive HD patients had DM + HTN aetiology, compared with only 17.8% of aCL-negative patients (p < 0.001). Thrombocytopenia was significantly more severe in aCL-positive patients (median platelets: 100 vs. 191 × 10⁹/L, p < 0.001). In multivariable analysis, DM + HTN etiology (HTN-alone vs. DM + HTN odds ratio [OR]: 0.0013, 95% confidence interval [CI]: 0.00002–0.0999, p = 0.003; confirmed by Firth’s penalized logistic regression sensitivity analysis, and lower platelet count (OR: 0.92 per 1 × 10⁹/L increase, 95% CI: 0.87–0.98, p = 0.006) independently predicted aCL positivity. Conclusions: These hypothesis-generating findings suggest a potential association between metabolic–vascular disease and antiphospholipid immunity in ESRD. Causality cannot be inferred from this cross-sectional design. At present, routine aCL screening is not recommended outside of research protocols; prospective studies are needed to confirm these associations. Full article

Syngas (synthesis gas) is a promising gaseous biofuel for small-scale power generation, but its highly variable composition, which depends on the biomass source and gasification process, poses challenges for engine optimization. This study investigates syngas–diesel dual-fuel combustion in an optically accessible engine using chemiluminescence imaging of OH*, CH*, and CH₂O* to characterize ignition and flame development. Three representative syngas compositions—Downdraft, Updraft, and Fluidbed—were examined. The Fluidbed composition exhibited the weakest OH* signal, approximately one-third of that observed for the other two, primarily due to its higher CO₂ dilution and lower H₂ content. Ignition delay trends were strongly correlated with dilution level: Downdraft and Updraft showed similar delays despite different H₂/CO ratios, while larger CO₂ shares led to longer delays and flattened heat-release rates. CH* and CH₂O* chemiluminescence showed better agreement with combustion timing than OH*. Methane enrichment enhanced flame propagation and reduced ignition delay, partially offsetting CO₂ dilution effects. Full article

Background: Test descriptions from major diagnostic manufacturers do not include ferritin reference intervals (RIs) for individuals aged 60 and older. The absence of older adults-specific RIs contrasts with the widespread use of serum ferritin testing in older adults. We aimed to establish and verify RIs using two common analytical methods. Methods: For this study, 1467 older adults were prospectively enrolled and monitored for morbidity and mortality, and exclusion criteria were applied. Ferritin was measured using chemiluminescent microparticle immunoassay (CMIA) and transferred to an electrochemiluminescence immunoassay (ECLIA) using method comparison. RIs were evaluated using a direct method with a prospective observational study based on healthy individuals according to the Clinical and Laboratory Standards Institute (CLSI) 28-A3c guideline and compared with RIs obtained using an indirect approach based on data obtained in clinical routine outpatients, where normal and abnormal values are supposed to be statistically differentiated to determine RIs. When applied within a countrywide population-based setting in Liechtenstein, the impact of novel RIs on the frequency of abnormal values was analyzed. Results: A total of 386 men and 532 women were included in the direct RI determination. Women (W) had significantly lower ferritin levels than men (M), while age over the age of 60 years had no significant association with ferritin in men and women. RIs were 23–241 ng/mL (W) and 19–396 ng/mL (M) for CMIA and 27–293 ng/mL (W) and 23–480 ng/mL (M) for ECLIA. These RIs are higher than those mentioned in the test descriptions in both tests. In comparison, the indirect method for both assays showed comparably lower reference limits, whereas upper reference limits were only approximately similar. The prevalence of high abnormal ferritin levels was considerably lower with this study’s RIs compared with manufacturer RIs. Conclusions: Employing older adults-specific RIs in clinical routine seems to be advisable. This reduces the frequency of abnormal high values in comparison with the widely applied practice of extrapolating RIs obtained from younger age groups to older adults and therefore leads to fewer follow-up investigations. Full article

Background: Screening for presymptomatic type 1 diabetes (T1D) reduces the risk of diabetic ketoacidosis (DKA) and allows for early intervention with disease-modifying therapies. Despite the rising incidence of T1D in Bulgaria, screening initiatives remain limited. This pilot study aims to evaluate the feasibility of selective T1D screening in high-risk children and identify potential clinical associations with islet autoimmunity. Methods: The study targeted a recruitment of 250 children aged 0–18 years (200 with a relative with T1D and 50 without). Screening for islet autoantibodies (AABs), including glutamic acid decarboxylase (GADA), insulin (IAA), insulinoma-associated-2 (IA-2A), zinc transporter-8 (ZnT8A), and islet cell cytoplasmic autoantibodies (ICAs), was performed via chemiluminescence immunoassay (CLIA). Participants testing positive for one or more AABs were scheduled for longitudinal immunological and metabolic follow-up to evaluate the persistence of autoimmunity and disease progression. Results: Between October 2024 and February 2026, the pilot study recruited 210 participants (84% of the 250 target), including 160 children with a relative (target 200) and 50 without a family history of T1D (target 50). Within the high-risk group, seven children (4.4%) tested positive for a single autoantibody (3 GADA, 2 ZnT8A, 1 IA-2A, and 1 IAA), while no autoantibodies were detected in the group without a relative. No cases of multiple autoantibody positivity or stage 3 T1D were identified in either group. Furthermore, no statistically significant associations were observed between autoantibody positivity and secondary factors, including breastfeeding, allergic status, a high-glycemic diet, frequent illness, and personal history of autoimmune disease. Conclusions: The findings validate the feasibility of selective T1D screening in Bulgaria, driven by high public interest and successful recruitment across both high-risk and general population cohorts. While this exploratory study found no significant clinical correlations, it establishes a vital roadmap for larger, longitudinal research. Ultimately, this pilot framework provides a scalable model for implementing standardized early detection to reduce the burden of T1D on the national healthcare system. Full article

Background/Objectives: Cortisol has become established as a relevant biomarker due to its association with various pathologies, including its potential utility in mental health research. However, regarding the techniques employed for its analysis, the available literature shows a certain degree of heterogeneity both in the methods used to obtain cortisol and in the analytical techniques employed for its measurement. This makes it difficult to compare results across specific populations, particularly in pregnant women, who experience metabolic and physiological changes characteristic of gestation. Therefore, the aim of this study was to describe the procedure for the extraction and analysis of cortisol in hair samples from pregnant women throughout gestation. Methods: Hair samples, three centimeters in length, were obtained from women during the first, second, and third trimesters of pregnancy. These samples underwent a standardized isopropanol washing step, followed by milling in a laboratory mill using zirconium balls of varying diameters. The resulting hair powder was then weighed and subjected to four incubation cycles using HPLC-grade methanol. Cortisol levels were detected using chemiluminescence immunoassay. Results: Mean hair cortisol levels were 4.1 μg/L (ng/mL) in the first trimester, 11.5 μg/L (ng/mL) in the second trimester, and 6.6 μg/L (ng/mL) in the third trimester. Conclusions: Standardizing the methodology for cortisol extraction improves the reproducibility of results and, in the long term, may support its incorporation into clinical practice as a useful tool for assessing cortisol levels in both pregnant women and the general population, since hair cortisol enables retrospective evaluation of its cumulative exposure over time, approximately on a monthly basis. Full article

Bladder cancer (BC) is one of the most common urinary tract malignancies. In recent years, increasing attention has been paid to the role of pyroptosis—an inflammatory form of programmed cell death—in cancer development. Gasdermin B (GSDM B), a member of the gasdermin protein family, is involved in the regulation of inflammatory processes and the immune response, and its expression may be associated with cancer development and progression. The aim of the study was to assess GSDM B concentrations in the serum of patients with bladder cancer and to determine its potential diagnostic value in comparison with the tumor markers carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9). This study included patients with bladder cancer hospitalized at the Department of Urology, Medical University of Białystok, and a healthy control group. GSDM B concentrations were determined by Enzyme-Linked Immunosorbent Assay (ELISA), while CEA and CA19-9 concentrations were determined by chemiluminescent microparticle immunoassay (CMIA). Concentrations in the serum of patients with bladder cancer were significantly higher than in the control group. A positive correlation was found between GSDM B and CEA and CA19-9 concentrations, as well as the age of the subjects. Receiver-operating characteristic (ROC) analysis demonstrated moderate but significant diagnostic value of GSDM B in differentiating patients with BC from healthy controls. No significant differences in GSDM B concentrations were observed between low- and high-grade tumors. These findings suggest that GSDM B may serve as a potential diagnostic marker for bladder cancer, particularly when used as part of a multimarker panel. Full article

Research into effective predictive markers and therapeutic interventions for COVID-19 remains of considerable interest. Vitamin D may be relevant, especially in frail populations in whom deficiency is more prevalent. In this prospective observational cohort study, 139 patients with moderate-to-severe COVID-19 who were hospitalized during the third wave of the pandemic in Italy were enrolled. Plasma vitamin D concentrations (both 25-hydroxyvitamin D-25(OH)D and 1,25-dihydroxyvitamin D-1,25(OH)₂D) together with parathyroid hormone levels were measured using a chemiluminescent assay validated for clinical use on automated laboratory platforms. Plasma vitamin D levels were below the sufficiency threshold. Notably, 25(OH)D concentrations were significantly lower in patients who experienced a negative outcome (11.10 [8.80–16.20] vs. 15.25 [9.90–24.80] ng/mL, p = 0.0450) and significantly higher in patients with rapid clinical recovery (15.25 [10.70–24.80] vs. 13.30 [7.47–19.60] ng/mL, p = 0.0446) compared with all other patients. Through multivariable logistic regression analysis, higher 25(OH)D levels at the time of hospitalization were confirmed as an independent predictor of favorable outcome. A plasma 25(OH)D concentration above 11.10 ng/mL predicted favorable disease resolution, with a positive likelihood ratio of 1.40 (IQR: 1.05–1.87). In conclusion, our findings support plasma vitamin D levels as an independent predictor of clinical outcomes in patients hospitalized with COVID-19 pneumonia. Full article

Background/Objectives: Aging is associated with declines in cognitive function and neurotrophic support. Brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-1 (IGF-1) are peripheral biomarkers discussed in relation to brain health and aging. This study investigated changes in serum BDNF, IGF-1, and cognitive screening scores after a 16-week Hatha Yoga program performed twice or four times per week in older women. Methods: Fifty-one community-dwelling women aged 70–79 years were allocated to a twice-per-week yoga group (2YG; n = 17), a four-times-per-week yoga group (4YG; n = 17), or a non-exercise control group (CON; n = 17) based on availability and participant preference; forty-three participants completed the study. Serum BDNF and IGF-1 were analyzed using enzyme-linked immunosorbent assay and chemiluminescent immunoassay, and cognitive status was evaluated using the Cognitive Impairment Screening Test (CIST). Outcomes were analyzed using two-way repeated-measures ANOVA and additional ANCOVA models adjusting for corresponding baseline values. Exploratory correlations were examined between biomarker changes and CIST changes. Effect sizes and 95% confidence intervals were reported. Results: BDNF showed a significant main effect of time (p < 0.05) without a significant group × time interaction; ANCOVA adjusting for baseline BDNF showed no significant group effect (p = 0.270). IGF-1 showed a significant group × time interaction (p < 0.01) with increases in both yoga groups; ANCOVA adjusting for baseline IGF-1 showed a significant group effect (p = 0.001). CIST showed a significant main effect of time (p < 0.01), but changes were small and the group × time interaction was not significant; ANCOVA adjusting for baseline CIST showed no significant group effect (p = 0.114). Biomarker changes were not clearly correlated with CIST changes (ΔBDNF–ΔCIST: r = −0.244, p = 0.115; ΔIGF-1–ΔCIST: r = −0.050, p = 0.750). Conclusions: In this quasi-experimental study with non-random allocation and limited covariate information, changes in peripheral neurotrophic factors and only small changes in cognitive screening scores were observed after participation in a 16-week Hatha Yoga program. However, frequency-dependent conclusions are limited, and findings should be interpreted cautiously as screening-level, hypothesis-generating reference data. Nevertheless, the program is considered a feasible, low-risk health promotion activity for older women and may inform future randomized or well-controlled studies. Full article

This exploratory study evaluated plasma atrial natriuretic peptide (ANP) concentrations in four species of captive cetaceans and their associations with physiological and environmental factors, including husbandry conditions, diet, and management practices. Twenty-six individuals were voluntarily sampled, and blood samples were analyzed using a human-based chemiluminescent immunoassay. Transthoracic echocardiography was also attempted in several individuals but was technically challenging due to interference from the lung tissue and the sternum. The mean plasma ANP concentration in clinically healthy young animals was 44.12 ± 14.62 pg/mL, with no significant differences observed according to age, sex, species, or the presence of mild chronic disease. ANP was detectable across all species using human reagents. In addition, brain natriuretic peptide (BNP), a commonly used cardiac biomarker in humans and other animals, was evaluated for comparison; however, BNP concentrations remained below the detection threshold, possibly reflecting species-specific differences. Importantly, ANP concentrations were not evaluated in animals with clinically significant disease, and therefore the relevance of these findings to diseased populations remains unknown. These results demonstrate that plasma ANP can be measured using existing clinical assays and provide preliminary baseline data for multiple cetacean species. Overall, ANP may offer preliminary insights into physiological variation in managed cetaceans; however, its utility as a biomarker for cardiovascular or systemic health assessment remains to be determined. Full article

Background: Psychological distress has been increasingly recognized as an important determinant of sleep quality in children and adolescents. However, susceptible subgroups have not been clearly identified. This study aimed to examine the associations between psychological distress and sleep quality in children and adolescents. Methods: We conducted a cross-sectional study among 5771 school-aged children and adolescents (6–18 years) in Zhejiang Province. Psychological status was assessed using the Chinese version of the Depression Anxiety Stress Scale-21, and sleep quality was evaluated using the Chinese version of the Pittsburgh Sleep Quality Index (PSQI). Thyroid-related biomarkers were measured via chemiluminescence immunoassay. Associations between psychological distress and sleep quality were analyzed using generalized linear models. In addition, stratified analyses were performed to identify potentially susceptible subgroups by age, sex, and BMI-for-age z score. Results: Each one-point increase in depression, anxiety, and stress scores was associated with an increase in PSQI scores of 0.18 (95% CI: 0.16, 0.19), 0.20 (95% CI: 0.18, 0.21), and 0.20 (95% CI: 0.19, 0.22), respectively. Subgroup analyses showed that the associations were more pronounced among older children (age > 12 years) and pediatric females. Exploratory mediation analyses suggested a possible but very limited indirect role of T3 in the associations of depression, anxiety, and stress with sleep quality, with all estimated proportions mediated below 1%. Conclusions: Psychological distress was significantly associated with poorer sleep quality in children and adolescents, particularly among older individuals and pediatric females. These findings highlight the importance of early identification and intervention for psychological distress to improve sleep health in younger populations. Further longitudinal studies are needed to clarify underlying mechanisms. Full article

Food safety requires real-time monitoring of mycotoxins in food, as food products contaminated with these toxins poses major threat to human health. In this study, we proposed a remote-controlled microfluidic platform (RCMP) integrated with chemiluminescent/colorimetric detection system for rapid, cost-effective and real-monitoring of multiple mycotoxins in real samples based on the indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). The RCMP enabled sensitive and automatic detection of deoxynivalenol (DON), zearalenone (ZEA), and fumonisin B1 (FB1) in the range of 4–128 ng/mL, 1–32 ng/mL, and 0.5–16 ng/mL, respectively. The limits of detection (LOD) were 2.881 ng/mL for DON, 0.702 ng/mL for ZEA, and 0.470 ng/mL for FB1. In further validation, satisfactory recoveries between 93.57% to 108.47% with the relative standard deviations (RSDs) of 6.92–11.39% were obtained in beer samples. Overall, RCMP provides an automatic, high-throughput and cost-effective method for detection of DON, ZEA, and FB1 and can be confidently applied for monitoring in beer samples. Full article

Comparative evaluations of different serological methods for the diagnosis of toxoplasmosis in pregnant women remain limited, and the performance of indirect immunofluorescence assay (IFA), modified agglutination test (MAT), and chemiluminescent microparticle immunoassay (CMIA) has not been previously assessed simultaneously in this population. This study aimed to compare the performance of these three serological methods for the detection of Toxoplasma gondii antibodies in pregnant women. A total of 469 serum samples were collected from pregnant women receiving prenatal care through the Brazilian public healthcare system. Samples were tested using IFA, MAT, and CMIA for the detection of IgG and IgM antibodies. Statistical analyses included McNemar’s χ² test, Kappa agreement, and Pearson and Spearman correlation coefficients. IFA and MAT showed higher IgG seropositivity rates (53.1% and 51.2%, respectively) compared to CMIA (46.7% and 48.6%). Agreement between CMIA and IFA was moderate for IgG (Kappa = 0.51) and very strong for IgM (Kappa = 0.89). Pearson’s correlation for IgG between CMIA and IFA was moderate (r = 0.678), while Spearman’s correlation for IgM was weak. IFA and MAT demonstrated greater sensitivity for IgG detection than CMIA, while CMIA and IFA performed similarly for IgM. Conventional methods may complement automated systems to improve diagnostic accuracy in prenatal screening. Full article

Background/Objectives: Understanding the relationship between reactogenicity and immunogenicity after repeated BNT162b2 vaccination is critical for optimizing vaccination strategies. This study quantified their progressive dissociation across four vaccine doses. Methods: We conducted a prospective longitudinal cohort study among Croatian healthcare workers vaccinated with BNT162b2 from January 2021 to January 2024. Anti-SARS-CoV-2 IgG antibodies were measured at 16 timepoints using chemiluminescent immunoassay. Local (pain, erythema, swelling) and systemic (fever, fatigue, headache, myalgia, arthralgia, nausea) reactions were recorded for 7 days using FDA toxicity scale. Correlations were analyzed with Spearman’s method and Bonferroni correction. Fourth-dose responses were predicted by exponential modeling. Results: Of 631 participants, 524 completed primary immunization, 418 received a third dose (173 with complete data), and 56 received a fourth dose (22 with complete paired data). Local reactions declined from 82.4% after the first dose to 42.9% after the fourth (p < 0.001). Systemic reactions peaked at 44.8% after the second dose, then decreased to 26.0% after the third and 19.6% after the fourth. In contrast, median antibody levels rose from 9910 AU/mL after the primary series to 29,002 AU/mL after the third and 38,274 AU/mL after the fourth. Correlations between reactions and antibody titer progressively weakened: r = 0.37 (95% CI 0.29–0.44, p < 0.001) after the primary series, r = 0.08 (95% CI −0.07 to 0.23, p = 0.30) after the third, and r = 0.04 (95% CI −0.39 to 0.45, p = 0.86) after the fourth dose. Conclusions: Progressive dissociation between reactogenicity and immunogenicity was observed across four BNT162b2 doses. Booster doses maintain robust antibody responses despite reduced reactogenicity, reinforcing that minimal side effects are consistent with sustained humoral responses. Full article