Search Results (639)

This non-randomized, open-labelled, controlled pilot trial investigated the impact of stunting on oral health and the oral microbiome, and evaluated the effect of 14-day probiotic or essential oil mouthwash interventions in children aged 8–12 years. Thirty-six participants (18 stunted, 18 non-stunted) were randomized into three parallel arms: probiotic lozenges (Limosilactobacillus reuteri DSM 17938 + ATCC PTA 5289), essential oil mouthwash, or water control. D-25OH level was assessed with ELISA, OHI-S, and PBI were examined, and oral microbiome was analyzed using 16S metagenomic sequencing. Stunted children demonstrated significantly higher gingival inflammation (PBI, F = 10.57, p = 0.002), reduced microbial alpha diversity, reductions in commensal Streptococcus spp., and increases in pathobionts, including Parvimonas micra, Fusobacterium nucleatum, and Tannerella forsythia. Beta-diversity analysis revealed distinct microbial communities (p = 0.001), with network analysis identifying these anaerobes as keystone hubs in stunted individuals. Salivary vitamin D and oral hygiene indices (OHI-S) also differed by stunting status. Fourteen-day interventions produced only modest, non-significant improvements in clinical indices and failed to induce significant shifts in microbial diversity or composition. These findings indicate that nutritional stunting is independently associated with oral dysbiosis and gingival inflammation. Short-term antiseptic interventions appear insufficient to reverse established microbial shifts, highlighting the need for sustained, integrated nutritional—oral health strategies. Full article

Long propagation delays, severe multipaths, and narrow bandwidths make feedback-based link adaptation impractical in UWA channels at kilometer ranges, so we replace the feedback step with a prediction step. The transmitter runs a two-layer coded OFDM link in which Polar codes handle bit errors, and Raptor fountain codes handle packet erasures, with the Raptor overhead (OH) as the only real-time knob. The OH is picked from a lookup table indexed by three quantities the receiver can estimate online: SNR, RMS delay spread, and Doppler frequency. Two CSI predictors feed that table: Temporal Multiple Sparse Bayesian Learning (TMSBL), which exploits delay-domain sparsity, and the Square-Root Unscented Kalman Filter (SRUKF), which tracks per-subcarrier variations. We evaluate the system in five channel environments (AWGN, Rayleigh, K-distribution, Bellhop ray-tracing, and synthetic proxies parameterized from the KAM11 and WATERMARK sea-trial statistics). Across the nine Bellhop scenarios, the adaptive link’s throughput gain over a fixed-OH ($\mathrm{OH}=1.5$) baseline at SNR $=4$ dB spans roughly $-4\%$ to $+30\%$, with the largest benefit in the marginal short-range cases (shallow 500 m, $+30\%$) where the fixed baseline is most over-provisioned and near-parity elsewhere. The scheme’s principal benefit is collapse prevention, tracking the Oracle within the safety margin and avoiding the throughput collapse the fixed baseline suffers at low SNRs. This effect is specific to the physically structured Bellhop channels; in the homogeneous Rayleigh and K-distribution channels, both schemes enter deep outage at very low SNRs, so it is not a universal guarantee. A 1000-trial high-resolution Rayleigh campaign sharpens the head-to-head between predictors: at SNR $=4$ dB, SRUKF + OH reaches PER $0.048$ (95% Wilson CI $[0.036, 0.063]$) and TMSBL + OH reaches $0.071$ ($[0.057, 0.089]$), and at SNR $=12$ dB, their throughputs ($0.748$ and $0.746$) are statistically indistinguishable from each other (95% Wilson halfwidth $\sim \pm$0.014) and lie close to the Oracle’s $0.768$ (within $\sim 0.02$). The two predictors therefore occupy overlapping operating regions once the safety margin is matched, and a sparsity-dependent tendency (TMSBL in sparse multipath, SRUKF in dense multipath) appears only in physically structured channels and only at the $n=100$ screening level, where it is not statistically resolved and would benefit from higher-trial confirmation. A finite-blocklength check confirms that CA-SCL-decoded Polar codes at $N=128$ stay within $0.5$ dB of the Polyanskiy normal approximation, which makes Polar a sensible inner code at UWA block lengths. Full article

The Shizui Cu–Pb–Zn deposit is located in central Jilin Province. It sits at the tectonic junction between the eastern Xing’an–Mongolia Orogenic Belt (XMOB) and the northeastern North China Craton (NCC). This is the first discovered Paleozoic Cu-polymetallic deposit in the region. Our study combines detailed geological investigation with systematic fluid inclusion analysis. We analyzed samples from four distinct paragenetic stages. Analytical methods include microthermometry, laser Raman spectroscopy, and hydrogen-oxygen isotope analysis. These data constrain the source, evolution, and precipitation mechanisms of the ore-forming fluids. The results delineate a clear evolutionary path: the ore-forming fluid originated as a high-temperature (346–437 °C), high-salinity (up to 51.68 wt.% NaCl equiv.) NaCl–H₂O–CO₂ system during the early quartz-sulfide stage (Stage I, Quartz ± Arsenopyrite ± Pyrite Stage), as evidenced by the coeval presence of high-salinity S-type and CO₂-rich C-type inclusions, indicating fluid immiscibility. The fluid then evolved into a boiling, medium temperature to high temperature (262–355 °C), high-salinity NaCl–H₂O system during the later part of early quartz-sulfide stage (Stage II, Quartz-Cu Polymetallic Sulfide Stage), a transition marked by the common coexistence of liquid-rich (L-type) and vapor-rich (V-type) inclusions with similar homogenization temperatures. This phase separation (boiling) served as the primary trigger for the massive deposition of chalcopyrite, arsenopyrite, and pyrite. Subsequently, the system cooled and diluted, transforming into a medium- to low-temperature (182–275 °C), low-salinity, partially homogeneous NaCl–H₂O system in the late quartz-sulfide stage (Stage III, Quartz-Pb-Zn Polymetallic Sulfide Stage). Finally, in the quartz-carbonate stage (Stage IV, Quartz-Carbonate Stage), the fluid temperature further decreased, resulting in a low-temperature (128–211 °C), low-salinity, homogeneous NaCl–H₂O system. Hydrogen-oxygen isotope data show that the calculated δ¹⁸O_H2O values decreased from +6.6‰ to +6.7‰ in Stage I to +3.4‰ to +3.9‰ in Stage II, and further to −0.4‰ in Stage III, while the δD values shifted from −91.6‰ to −90.6‰, to −94.4‰ to −94.2‰, and finally to −95.7‰. This trend indicates that the initial magmatic fluid progressively mixed with meteoric water. The geological characteristics, spatial association with Hercynian biotite monzogranite, developed skarn alteration, and the documented fluid evolution trajectory collectively affirm that the Shizui deposit is a typical skarn-type system. The deposit shares significant similarities in mineralization conditions, age, and tectonic setting with the skarn-type Tianbaoshan Pb–Zn–Cu–Mo deposits in the western segment of the XarMoron–Changchun Metallogenic Belt (XCMB). This correlation strongly suggests that the Paleozoic XCMB extends eastward and holds considerable potential for the discovery of late Paleozoic skarn-type Cu-polymetallic deposits in its eastern part. Full article

Background: Late-onset neonatal sepsis (LONS) remains a major cause of morbidity in preterm neonates admitted to the neonatal intensive care unit (NICU), yet the contribution of vitamin D status to neonatal infectious susceptibility remains uncertain. Objective: To evaluate clinical and demographic variables and serum vitamin D levels assessed at birth in preterm neonates with and without LONS. Methods: A retrospective observational cohort study was conducted in a tertiary NICU in northeastern Mexico between May 2023 and October 2024. Preterm neonates (<37 weeks of gestation) with serum 25(OH)D measured within the first hour of life were included. Vitamin D status was classified as sufficient (≥30 ng/mL), insufficient (20–29 ng/mL), or deficient (<20 ng/mL). LONS was defined as sepsis occurring after 72 h of life. Comparisons between neonates with and without LONS were performed using Fisher’s exact test for categorical variables and Student’s t-test or Mann–Whitney U test for continuous variables, as appropriate. Results: Twenty-nine preterm neonates were included (mean gestational age: 32.0 ± 2.6 weeks; mean birth weight: 1748 ± 545 g). The mean serum 25(OH)D level at birth was 35.5 ± 13.0 ng/mL. LONS occurred in 31% (9/29) of neonates, of which 55% were microbiologically confirmed. No significant differences were observed in vitamin D levels between neonates with and without LONS (35.0 ± 12.0 vs. 35.7 ± 13.7 ng/mL; p = 0.899). Vitamin D deficiency was not associated with LONS (OR 1.13, 95% CI 0.09–14.28). The prevalence of vitamin D deficiency was low (10%) in this cohort. Conclusions: A clear association between serum 25(OH)D levels at birth and the development of LONS could not be demonstrated in this small exploratory cohort. Given the limited sample size and low prevalence of vitamin D deficiency, further multicenter prospective studies are required to better understand the potential relationship between vitamin D status and neonatal infectious outcomes. Full article

The development of highly efficient and stable photoanodes is essential for advancing photoelectrochemical cathodic protection towards practical applications. Herein, a novel ternary sulfide heterojunction was engineered through the construction of a three-dimensional interlocked architecture of ZnIn₂S₄ on SnIn₄S₈ nanosheets via a sequential hydrothermal synthesis. This unique three-dimensional interlocked configuration creates an intimate interface and continuous charge transfer highways, effectively addressing the slow electron movement and poor interfacial contact that plague conventional photoelectrodes. Spectroscopic and electrochemical analyses verified the formation of a Type-II band alignment, which drives the directional migration of photogenerated electrons from ZnIn₂S₄ to SnIn₄S₈ under an intrinsic built-in electric field. Upon coupling with 304 stainless steel, the ZnIn₂S₄/SnIn₄S₃ heterojunction exhibited outstanding photoelectrochemical cathodic protection performance. It delivered impressive photocurrent densities of 15.22, 19.76, and 72.27 μA·cm⁻² in 3.5 wt% NaCl, 0.1 M Na₂S₂O₃, and 0.1 M Na₂S/NaOH electrolytes, respectively, along with a prominent 720 mV cathodic potential shift in the Na₂S/NaOH system. Most importantly, its good activity and stability in the scavenger-free 3.5 wt% NaCl solution and natural seawater highlight the strong practical potential of this 3D interlocked photoanode for sustainable marine metal corrosion control. Through a strategic multi-electrolyte assessment, the underlying protection mechanisms were decoupled, revealing that the synergy between the heterojunction-induced charge separation enabled by the three-dimensional interlocked structure and electrolyte-specific hole scavenging is key to the enhanced performance. Full article

Acute ischemic stroke (AIS) is associated with redox imbalance; however, the early temporal changes in enzymatic and non-enzymatic antioxidant responses are poorly understood. The aim of this study was to evaluate changes in selected oxidative stress markers during the early phase of AIS. The study was designed as a longitudinal within-subject analysis, with each patient serving as their own reference between day 1 and day 8. A total of 48 patients (mean age 69.31 ± 1.59 years; 56.3% male; mean body mass index (BMI) 27.05 ± 0.61 kg/m²), predominantly presenting with mild to moderate stroke severity, were enrolled in a prospective observational study. The cohort was characterized by a high prevalence of hypertension (87.5%), dyslipidemia (45.8%), and diabetes or prediabetes (45.9%). Blood samples were collected on day 1 and day 8 after stroke onset. Depending on the distribution of paired differences, either the paired Student’s t-test or Wilcoxon signed-rank test was applied. A significant increase in superoxide dismutase (SOD) activity was observed (1932.73 vs. 2086.55 U/g Hb, p = 0.032), whereas catalase (CAT; 403.19 vs. 415.30 × 10³ U/g Hb, p = 0.444) and glutathione peroxidase (GPx; 24.70 vs. 24.40 U/g Hb, p = 0.477) showed no significant changes. Similarly, malondialdehyde (MDA) levels remained stable in both erythrocytes (182.96 vs. 187.15 nmol/g Hb, p = 0.838) and plasma (0.41 vs. 0.41 nmol/mL, p = 0.922). In contrast, melatonin (59.65 vs. 55.49 pg/mL, p = 0.042) and 25-hydroxyvitamin D (25(OH)D; 19.31 vs. 16.52 ng/mL, p < 0.001) concentrations significantly decreased. These findings suggest that the early phase of AIS may be associated with a selective and potentially maladaptive antioxidant response, involving increased SOD activity alongside depletion of systemic modulators, which may contribute to persistent redox imbalance. Full article

In the present study, innovative active gelatin–chitosan films enriched with blackberry (ACTIVE-BF) and sage flower (ACTIVE-SF) extracts were developed and comprehensively characterised with regard to their physicochemical, functional and environmental properties. The incorporation of phenolic compounds increased the film’s UV–Vis (ultraviolet–visible spectroscopy) absorbance, confirming the presence of chromophoric groups and the improvement of light-barrier properties. FTIR (Fourier Transform Infrared Spectroscopy) analysis revealed hydrogen bond formation and intermolecular interactions between polyphenols and the –OH/–NH groups of the biopolymer matrix, which enhanced the structural stability of the films. Adding blackberry and sage extracts slightly increased the hydrophilicity and solubility of the films (40–48%), without significantly affecting their water vapour transmission rate (531–547 g/m²·d). The obtained films exhibited strong antioxidant activity, with FRAP (Ferric Reducing Antioxidant Power) values ranging from 17.75 to 40.83 mM Trolox/mg, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging capacity between 42.58 and 46.88%, and metal chelating ability up to 50.82%. During the nine-day storage of salmon fillets at 4 °C, the active films effectively inhibited microbial growth (reduction of 1.5–2.1 log CFU/g) while maintaining pH stability (6.2–6.4). Respiration activity confirmed environmental safety. The developed materials represent biodegradable, multifunctional films with high potential for application as sustainable active packaging for perishable food products. Full article

Background and Objectives: Continuous positive airway pressure (CPAP) is the standard first-line treatment for patients with obstructive sleep apnea (OSA). Patients with OSA exhibit a higher prevalence of vitamin D deficiency, and CPAP treatment has been reported to improve vitamin D levels. Therefore, the aim of this study was to investigate the association between vitamin D deficiency and the risk of patients receiving a diagnosis of OSA or utilizing CPAP, using the TriNetX research network to obtain real-world data. Materials and Methods: A retrospective cohort study using the TriNetX database was conducted to investigate the relationship between vitamin D deficiency and patients with risk of receiving an OSA diagnosis or patients treated with CPAP in older adults (≥65 years). Patients were stratified into four groups according to serum 25-hydroxyvitamin D [25(OH)D] levels: severe deficiency (D10, ≤10 ng/mL), mild deficiency (D20, 11–20 ng/mL), insufficient vitamin D status (S30, 21–30 ng/mL), and normal vitamin D status (N100, 31–100 ng/mL). After 1:1 propensity score matching (PSM) to adjust for baseline covariates, patients were followed for up to 5 years for newly diagnosed OSA and CPAP use (an administrative-clinical outcome influenced by non-disease-related factors such as healthcare access and clinical practice), with vitamin D status assessed at the index date. An anchor-based network meta-analysis was also performed to integrate direct and indirect evidence across groups. Results: A total of 2,289,855 eligible patients were included and stratified into four groups: D10 (n = 161,610; 7.06%), D20 (n = 404,954; 17.68%), S30 (n = 648,989; 28.34%), and N100 (n = 1,074,302; 46.92%). Across the six pairwise comparisons, pre-matching baseline imbalances showed consistent patterns: lower vitamin D groups (particularly D10 and D20) generally had older age at index (in comparisons with S30 or D20), a higher proportion of males, and higher proportions of Black/African American patients, whereas higher vitamin D groups (especially N100 and S30) had higher proportions of White patients (and, in some comparisons, Asian patients). Comorbidity differences were modest overall, and these imbalances were substantially reduced after PSM. In both pairwise PSM analyses and the anchor-based network meta-analysis, severe vitamin D deficiency was observationally associated with the risk of receiving an OSA diagnosis and CPAP use. An observational trend appeared across vitamin D categories (D10 > D20 > S30), suggesting an association. The associations were strongest at 1 year and gradually attenuated over the 3- and 5-year follow-up periods. An E-value greater than 3 was observed only for the comparison between the D10 and N100 groups. Conclusions: In this real-world analysis of older adults, vitamin D deficiency, particularly severe deficiency, was observationally associated with increased 5-year risk of receiving an OSA diagnosis and CPAP use. Similarly, anchor-based network meta-analysis also showed an association between vitamin D deficiency severity and the risk of receiving an OSA diagnosis and CPAP use. Full article

Background: Asthma is a heterogeneous chronic inflammatory airway disease characterized by recurrent exacerbations and variable airflow limitation. Epithelial-derived alarmins, particularly interleukin-33 (IL-33) and its receptor ST2, play key roles in type 2 inflammation. The soluble form of ST2 (sST2) acts as a decoy receptor regulating IL-33 signaling. Vitamin D is an important immunomodulator influencing airway inflammation, but its interaction with the IL-33/ST2 pathway remains unclear. Objective: To evaluate the association between serum IL-33, sST2, and 25-hydroxyvitamin D [25(OH)D] levels with asthma severity and exacerbation status, and to assess their potential as clinical biomarkers. Methods: This study enrolled 52 adult asthma patients (27 experiencing exacerbation and 25 in remission) and 28 healthy controls. Serum levels of IL-33 and sST2 were measured using enzyme-linked immunosorbent assays, while 25(OH)D concentrations were determined via electrochemiluminescence immunoassay. Results: Serum sST2 levels were significantly higher and 25(OH)D levels significantly lower in asthma patients compared with controls (p < 0.000 for both). Serum IL-33 levels did not differ significantly between groups (p > 0.05). During exacerbation, sST2 levels were markedly elevated compared with remission (p < 0.001), whereas vitamin D levels were significantly reduced (p = 0.038). A significant negative correlation was identified between sST2 and 25(OH)D (r = −0.333, p = 0.016). Conclusions: The presence of asthma and the severity of exacerbations are associated with elevated circulating sST2 levels and reduced vitamin D levels. These findings suggest a regulatory interaction between vitamin D and the IL-33/ST2 axis in airway inflammation and indicate that targeting this axis could be a potential therapeutic strategy. Full article

Accurate quantification of soil moisture (m_v) is of great scientific significance for regional hydrological modeling, meteorological forecasting, and drought and flood disaster monitoring. Although C-band SAR aboard the GF-3 satellite constellation supports large-scale retrieval, existing studies are mostly confined to local validation under simple surface conditions. Its retrieval performance across varied surface roughness (s), m_v, soil texture, and topography, as well as the synergistic retrieval ability of the satellite constellation, has not been fully investigated. Therefore, this study systematically evaluated four m_v retrieval strategies using quality-controlled satellite-ground synchronous observation data from 11 arid-to-humid experimental areas (378 plots) in China: Oh94 model inversion (Strategy I), calibrated Oh94 model inversion (Strategy II), calibrated Oh94 model inversion with prior constraints on m_v and s (Strategy III), and random forest inversion (Strategy IV). Subsequently, the measured satellite backscattering coefficients (${\sigma }_{\mathrm{obs}}^0$) were compared with model simulations (${\sigma }_{\mathrm{sim}}^0$), yielding initial biases of 2.08 dB, 0.78 dB, and −0.29 dB for VV, HH, and HV polarizations, respectively, and these biases were significantly reduced to −0.01 dB, 0.00 dB, and −0.06 dB after systematic deviation correction (SDC). Overall, the root-mean-square errors (RMSE) of m_v retrieval for Strategies I–IV were 0.092, 0.078, 0.058, and 0.046 cm³·cm⁻³, respectively, while those for s retrieval were 0.620, 0.578, 0.610, and 0.403 cm. Strategy IV achieved the highest m_v retrieval accuracy owing to the robust nonlinear predictive capacity of machine learning. Nevertheless, Strategy III exhibited superior transferability in spatially independent validation, with an RMSE of 0.054 cm³·cm⁻³, outperforming Strategy IV (0.065 cm³·cm⁻³). This demonstrates that Strategy III possesses a stronger generalization ability than purely data-driven models under domain shifts. By incorporating prior constraints, Strategy III effectively mitigated radiometric inconsistencies within the satellite constellation, and m_v retrieval biases among GF-3, GF-3B, and GF-3C converged stably within 0.021 cm³·cm⁻³, with RMSE ranging from 0.046 to 0.079 cm³·cm⁻³. This study validates the feasibility of synergistic m_v retrieval over bare surfaces using the GF-3 SAR constellation, providing critical technical support for large-area operational mapping. Full article

With the rapid progression of global industrialization and urbanization, heavy metal contamination has emerged as a major global threat, especially cadmium pollution. Consequently, optimizing remediation measures has become a pivotal means to solve cadmium contamination. Compared to traditional physical and chemical remediation methods, microbial remediation has great potential in addressing cadmium pollution. In this study, a novel bacterial strain, Chryseobacterium sp. HGX-24, exhibiting high cadmium resistance was successfully isolated and screened from cadmium-contaminated environments. A preliminary discussion of the response mechanisms of this strain under cadmium stress is provided. Additionally, preliminarily explored the synergistic remediation of microbial-plant in cadmium-contaminated soil. Under conditions of high cadmium concentration, cadmium ions were effectively adsorbed by strain HGX-24 through extracellular polymers and functional groups on the cell wall surface, including −COOH, −CONH−, −NH, −OH, and >C=O. Extracellular proteins and polysaccharides were secreted by strain HGX-24 to regulate the adverse effects of heavy-metal cadmium ions on bacterial growth. Furthermore, the expression of genes such as antioxidant defense and ROS scavenging (katG, fabG, ybjT), Fe-S cluster assembly (sufB, sufD), sulfur metabolism (cysAU), amino acid metabolism (hisA, cysD, aspC), phenylacetic acid catabolism (paaC), and ribosomal proteins (rplC, rpsC, rpsL, rplA, rplY, rpmC) was regulated, affecting the synthesis and metabolism of membrane transporters (ABC transporters and efflux RND transporters), antioxidant enzymes (SOD, COT, POD), Fe-S clusters, thioredoxin family proteins, and ribosomal proteins, thereby enhancing resistance to cadmium toxicity. Moreover, strain HGX-24 was found to regulate the activities of redox enzymes in Zea mays L., thereby alleviating oxidative stress and reducing the negative feedback effects of reactive oxygen species in Z. mays. Full article

Background: Vitamin D deficiency in early childhood is commonly defined using fixed 25(OH)D thresholds, most often <20 ng/mL. However, inclusion of the C3-epimer (3-epi-25(OH)D₃) in total 25(OH)D measurements may influence classification, particularly in children with borderline concentrations. Methods: In this cross-sectional study of 128 children aged 0–36 months, vitamin D metabolites were quantified using LC–MS/MS in dried blood spot (DBS) samples. Vitamin D deficiency was defined as <20 ng/mL. Total 25(OH)D was recalculated after subtraction of the C3-epimer to assess changes in deficiency classification. Agreement was evaluated using Cohen’s κ, and systematic differences were tested with McNemar’s test. Diagnostic performance parameters were calculated using epimer-resolved 25(OH)D as the reference standard. Results: Mean 25(OH)D₃ concentration was 20.3 ± 6.2 ng/mL, and 57% of children were classified as deficient. After epimer subtraction, deficiency classification changed in 22 of 128 children (17.2%). Agreement between classifications was substantial (κ = 0.67), but McNemar’s test demonstrated a significant systematic shift (p < 0.001). Sensitivity of total 25(OH)D including the epimer for detecting deficiency was 70.3% (95% CI: 59.0–80.0%), with specificity of 100% (95% CI: 94.3–100%). Reclassification was strongly concentrated among children with borderline 25(OH)D₃ concentrations (18–22 ng/mL), where 54.5% were reclassified compared with 4.2% outside this range. Reclassification was not associated with age. Conclusions: In young children, inclusion of the C3-epimer in total 25(OH)D measurement leads to potentially clinically relevant misclassification of vitamin D deficiency, particularly near diagnostic thresholds. Epimer-resolved assessment may improve diagnostic precision in cases with borderline vitamin D concentrations. Full article

Background: Vitamin D status is influenced by season, age, and public health messaging. The COVID-19 pandemic was accompanied by heightened interest in vitamin D, but long-term national data from Central/Eastern Europe remain limited. We aimed to characterize 10-year trends, seasonal variation, and demographic determinants of serum 25-hydroxyvitamin D [25(OH)D] in Slovenia, with particular focus on changes during the COVID-19 period. Methods: We performed a retrospective cross-sectional analysis of all serum 25(OH)D measurements performed at the Slovenian national reference laboratory between January 2014 and December 2023. The core analytic cohort included 106,875 patients with valid 25(OH)D results, aged 0–100 years. Vitamin D status was classified as deficient (<30 nmol/L), insufficient (30–50 nmol/L), adequate (50–75 nmol/L), and optimal (>75 nmol/L). Temporal trends, seasonal patterns, and age- and sex-specific differences were assessed using non-parametric tests and Kendall’s τ. Results: Mean 25(OH)D concentration over the study period was 61.9 ± 34.2 nmol/L; 16.0% of patients were deficient and 22.8% insufficient. Annual mean 25(OH)D increased from 57.0 nmol/L in 2014 to 67.2 nmol/L in 2023, with a significant upward temporal trend and a 14.6% higher mean level during 2020–2023 compared with 2014–2019. Seasonal variation was pronounced (≈20% higher summer–autumn vs. winter–spring), and vitamin D status declined progressively with age, with the highest deficiency prevalence in patients ≥ 70 years. Females had slightly higher 25(OH)D than males, although absolute differences were small. Conclusions: This laboratory-based analysis of tested patients showed higher 25(OH)D concentrations during and after the COVID-19 period, superimposed on persistent seasonal and age-related gradients. These observations identify older adults and winter testing periods as important contexts for vitamin D optimization, but they should be interpreted as descriptive trends among tested individuals rather than as evidence of causal pandemic effects or population-wide prevalence changes. Full article

Background: Chronic obstructive pulmonary disease (COPD) is associated with systemic inflammation and frequent exacerbations, leading to disease progression and increased morbidity. Vitamin D deficiency has been suggested to contribute to COPD inflammation and exacerbations. Aim: This study investigated the association between serum 25-hydroxyvitamin D (25(OH)D) levels, systemic inflammation, and exacerbation frequency among patients with COPD GOLD group E. Methods: A cross-sectional study was conducted on 111 patients with stable COPD. Patients were divided into two groups based on their serum 25(OH)D levels (<50 nmol/L vs. ≥50 nmol/L). Data on exacerbation frequency for the past year, inflammatory markers, spirometric lung function parameters, and symptom burden were collected. Results: Patients with low serum 25(OH)D (<50 nmol/L) had a significantly higher CAT score and level of serum high-sensitivity (hs)-CRP and exhibited significantly more exacerbations compared to those with higher 25(OH)D levels (p < 0.001, p < 0.001, and p < 0.0001, respectively). Furthermore, lower vitamin D levels were associated with higher CAT scores (Pearson’s correlation coefficient, r = −0.30, p < 0.01) and higher serum hs-CRP levels (Spearman’s rank correlation coefficient, r = −0.25, p < 0.01), as well as a higher number of exacerbations (Pearson’s correlation coefficient, r = −0.74, p < 0.0001). Conclusions: Low vitamin D levels are significantly associated with greater symptom burden, elevated hs-CRP, and increased exacerbation frequency, indicating a strong relationship between vitamin D deficiency, systemic inflammation, and disease burden in patients with COPD belonging to GOLD group E. However, due to the cross-sectional design, no causal relationship can be inferred and prospective interventional studies are required to determine whether treating vitamin D deficiency improves clinical outcomes. Full article

Background/Objectives: Acute high-intensity exercise may transiently alter circulating vitamin D metabolites. However, the effects of training status, supplementation dose, and vitamin D-binding protein (VDBP) on the exercise-induced redistribution and bioavailability of vitamin D remain unclear. This pilot study examined whether training status and vitamin D₃ supplementation dose modulate vitamin D status, anaerobic performance, and acute post-exercise changes in vitamin D metabolites and VDBP. Methods: Thirty-four healthy young men participated, comprising 22 mixed martial arts (MMA) athletes and 12 untrained controls. MMA athletes received either 3500 or 6000 IU/day of vitamin D₃ for four weeks, while untrained participants received 3500 IU/day or a placebo. Before and after the intervention, participants performed a supramaximal anaerobic exercise protocol (3 × 30 s Wingate tests). Blood samples were collected at rest and 30 min and 24 h post-exercise to assess vitamin D metabolites, VDBP, bioavailable and free 25(OH)D₃, interleukin-6, and lactate. Results: Supplementation with 3500 IU/day significantly increased serum 25(OH)D₃ in untrained men (p = 0.003) but not in MMA athletes. In contrast, 6000 IU/day increased 25(OH)D₃ in MMA athletes to a sufficient concentration (p = 0.001) and improved maximal power (+7.5%), mean power (+4.9%), and total work (+5.0%). Acute exercise increased circulating vitamin D metabolites in trained athletes but reduced them in untrained men supplemented with vitamin D. Conclusions: The efficacy of vitamin D₃ supplementation and the acute exercise-induced vitamin D responses appear to be training-dependent. A daily dose of 6000 IU is more effective in achieving vitamin D sufficiency and performance benefits in MMA athletes, whereas 3500 IU is sufficient for untrained men. Full article