Search Results (66)

Dental tissue regeneration, particularly alveolar bone and gingival repair, remains a major challenge in regenerative medicine. 3D bioprinting offers patient-specific and anatomically precise constructs, representing an advanced alternative to conventional grafting. In this study, nanohydroxyapatite (nHA), chitosan (CS), and collagen (CoL) were combined to fabricate and characterize 3D bioprinted dental grafts. SEM revealed a highly porous, interconnected architecture favorable for cell infiltration and nutrient exchange. EDS confirmed Ca/P ratios of 2.06 for nHA/CoL and 1.83 for nHA/CS/CoL, both of which are above the stoichiometric 1.67, indicating the presence of additional mineral phases and ion substitutions. FTIR and XRD verified characteristic functional groups and crystalline phases, including B-type HA with carbonate substitution. Mechanical testing showed that pure nHA exhibited the lowest compressive strength, whereas CoL incorporation improved stiffness. The nHA/CS/CoL composite achieved the highest compressive strength, elastic modulus, and toughness, demonstrating superior mechanical resilience. DSC analysis indicated endothermic peaks at 106.49 °C and 351.91 °C, with enthalpy values (264.91 J/g and 15.09 J/g) surpassing those of nHA alone. TGA revealed ~28.8% weight loss across three degradation stages, confirming enhanced thermal stability. In vitro cytocompatibility testing using L929 fibroblasts validated the biocompatibility of the composites. Collectively, the synergy between bioceramics and biopolymers markedly improved both mechanical and thermal performance. These findings position the nHA/CS/CoL scaffold as a promising candidate for clinical applications in dental tissue regeneration. Unlike conventional grafting materials, this study introduces a synergistically optimized nHA/CS/CoL bio-ink formulation specifically designed for extrusion-based 3D bioprinting of patient-specific dental constructs. The core innovation lies in the precise integration of nHA within a dual-polymer matrix (CS/CoL), which bridges the gap between mechanical resilience and biological signaling, achieving a compressive strength that mimics native alveolar bone while maintaining high cytocompatibility. Full article

Nitrogen (N) application rates and irrigation regimes are key factors determining rice yield and N use efficiency. To evaluate the effects of different irrigation regimes and N application rates on rice yield and N uptake, a four-year field experiment was conducted from 2021 to 2024 at the Qing’an National Irrigation Experimental Station in Heilongjiang Province. The experiment included two irrigation regimes (C: Controlled irrigation and F: Flooded irrigation) combined with four N application rates (N0: 0 kg N·ha⁻¹, N1: 82.5 kg N·ha⁻¹, N2: 110 kg N·ha⁻¹, and N3: 137.5 kg N·ha⁻¹). The results showed that, considering the same N application rate, C promoted dry matter accumulation by 3% to 9% and total N accumulation by 4.1% to 25.5% in the aboveground parts of rice compared to F. Under the same irrigation regime, total N accumulation in the aboveground parts of rice increased with N application rate and then plateaued. Regarding the distribution of N among organs, the proportion of panicle N relative to total N in the aboveground parts of rice followed an initial increase and subsequent decline as N input increased, resulting in the nitrogen harvest index (NHI) reaching its maximum under the moderate N treatment (N2). Overall, controlled irrigation significantly improved the NHI and AE, whereas the moderate N treatment (N2) further increased the NHI and promoted greater N allocation to panicles. Therefore, combining C with a moderate N application rate can enhance N use efficiency and markedly improve the internal N partitioning pattern. Full article

Nitrogen (N) uptake of managed turfgrasses in sand rootzones is of particular importance as it relates to reducing N leaching, reducing or maximizing N fertilizer applications, and optimizing overall plant quality. Two greenhouse experiments were conducted to determine if the inclusion of a one-time application of soil surfactant tank-mixed with ammonium sulfate fertilizer (FERT) improved fertilizer longevity and bermudagrass (Cynodon dactylon L. Pers. × C. transvaalensis Burtt-Davy, cv. ‘TifEagle’) quality (TQ), yield, leaf N content, N uptake (NUP), chlorophyll index (CI), and volumetric water content (VWC) under deficit irrigation. An untreated, fertilizer-only (Fert) (49 kg N·ha⁻¹), and non-ionic alkylpolyglycoside/ethylene oxide-propylene oxide (AEP) was tank-mixed with fertilizer at two rates, Fert+AEP(L) (1.17 L·ha⁻¹) or Fert+AEP(H) (1.75 L·ha⁻¹), to determine rate efficacy. In 2015, Fert and Fert+AEP(L) significantly increased TQ and CI, while in 2016, both AEP (L and H) significantly increased only TQ. VWC was significantly greater in untreated in 2015. At the end of the trials in 2015 and 2016, yield and NUP were significantly greater in Fert+AEP(H) and Fert+AEP(L), respectively, but leaf N content was not statistically significant between all fertilizer treatments. The role of surfactants in prolonging fertilizer effectiveness under deficit irrigation warrants further investigation. Full article

Flexible pavements using conventional bitumen are prone to suffering severe distress in hot climates, particularly rutting and moisture-induced damage. This study explores synergistic effects of waste-derived High-Density Polyethylene (HDPE) and Bakelite as dual modifiers for asphalt mixtures under Pakistan’s extreme climate, where summer temperatures exceed 45 °C. Modified mixtures were prepared via wet process using HDPE (3%, 6%, 9% by weight of optimum bitumen content) combined with 6% Bakelite, evaluated against control mixtures (60/70 bitumen, NHA Class-B gradation). Performance assessment included indirect tensile strength, moisture susceptibility (TSR), resilient modulus, and Hamburg wheel tracking tests. The optimal 6%HDPE + 6%Bakelite formulation achieved remarkable improvements over control: 24.7% higher dry ITS (0.647 MPa), 48.7% higher conditioned ITS (0.617 MPa), 95.36% TSR (19% above specifications), 43.7% greater resilient modulus (4866 MPa), and 27.4% lower rutting depth (2.38 mm). These enhancements are likely associated with the development of a stiffer polymer resin network between HDPE and rigid Bakelite particles, which appears to provide a favorable balance between mixture flexibility and stiffness. At 9% HDPE, performance degradation in strength and moisture-related properties suggests possible phase separation, although rutting resistance continued improving. This dual-modification strategy provides sustainable, cost-effective enhancement of pavement durability in hot climates while addressing waste management challenges, offering significant potential for reducing maintenance costs and extending service life. Full article

Crops nitrogen supply through the in situ mineralization of soil organic matter is a critical process for plant nutrition. However, accurately estimating the contribution of mineralization remains challenging. The complexity of biological, chemical, and physical processes in the soil, influenced by environmental conditions, makes it difficult to precisely quantify the amount of nitrogen available for crops. In this study, we created a database by collecting results from 121 mineralization monitoring experiments carried out between 2015 and 2021 on different experimental plots across Wallonia, Southern Belgium, and assessed the efficiency of predictive mineralization methods. The most impactful analytical parameters on in situ mineralization (ISM), determined using LIXIM program, appeared to be potentially mineralizable nitrogen (PMN) (r = 0.79). PMN, estimated by anaerobic soil incubation, also allowed the effective consideration of the after-effects of grassland termination and manure inputs. A multiple linear regression (MLR) combining PMN, POxC, pH, TOC:N, and TOC:clay significantly improved the prediction of soil nitrogen mineralization available for crops, achieving r = 0.87 (vs. r = 0.58 for the current method), while reducing dispersion by 41% (RMSE 56.35 → 33.13 kg N·ha⁻¹). The use of a more flexible Bootstrap Forest model (BFM) further enhanced performance, reaching r = 0.92 and a 50.8% reduction in dispersion compared to the current method (RMSE 56.35 → 27.76 kg N·ha⁻¹), i.e., about 16% lower RMSE than the MLR. Those models provided practical and efficient tools to better manage nitrogen resources in temperate agricultural systems. Full article

Soybean (Glycine max [L.] Merr.) cultivation is expanding in Central Europe due to the development of early-maturing cultivars and growing demand for plant-based protein produced without the use of genetically modified organisms. However, nitrogen (N) management remains a major challenge in temperate climates, where variable weather conditions can significantly affect nodulation and yield. This study evaluated the effects of three nitrogen fertilisation doses (0, 30, and 60 kg N·ha⁻¹), applied in the form of ammonium nitrate (34% N) and two commercial rhizobial inoculants—HiStick Soy (containing Bradyrhizobium japonicum strain 532C) and Nitragina (including a Polish strain of B. japonicum)—on nodulation, nitrogen uptake, and seed yield. A three-year field experiment (2017–2019) was conducted in southwestern Poland using a two-factor randomized complete block design. Nodulation varied significantly across years, with the highest values recorded under favourable early-season moisture and reduced during drought. In the first year, inoculation with HiStick Soy significantly increased nodule number and seed yield compared to Nitragina and the uninoculated control. Nitrogen fertilisation consistently improved seed yield, although it had no significant effect on nodulation. The highest nitrogen use efficiency was observed with moderate nitrogen input (30 kg N·ha⁻¹) combined with inoculation. These findings highlight the importance of integrating effective rhizobial inoculants with optimized nitrogen fertilisation to improve soybean productivity and nitrogen efficiency under variable temperate climate conditions. Full article

Vibrio parahaemolyticus is a major foodborne pathogen worldwide, responsible for seafood-associated poisoning. Among its toxin genes, tdh2 is the most critical. To investigate the role of tdh2 in V. parahaemolyticus under gastrointestinal conditions, we constructed tdh2 deletion and complementation strains and compared their survival under acid (pH 3 and 4) and bile stress (2%). The results showed that tdh2 expression was significantly upregulated under cold (4 °C) and bile stress (0.9%). Survival assays and PI staining revealed that the tdh2 mutant strain (VP: △tdh2) was more sensitive to acid and bile stress than the wild-type (WT), and this sensitivity was rescued by tdh2 complementation. These findings suggest that tdh2 plays a protective role in enhancing V. parahaemolyticus tolerance to acid and bile stress. In the VP: △tdh2 strain, seven genes were significantly upregulated and six were downregulated as a result of tdh2 deletion. These genes included VPA1332 (vtrA), VPA1348 (vtrB), VP2467 (ompU), VP0301 and VP1995 (ABC transporters), VP0527 (nhaR), and VP2553 (rpoS), among others. Additionally, LC-MS/MS analysis identified 12 differential metabolites between the WT and VP: △tdh2 strains, including phosphatidylserine (PS) (17:2 (9Z,12Z) /0:0 and 20:1 (11Z) /0:0), phosphatidylglycerol (PG) (17:0/0:0), flavin mononucleotide (FMN), and various nucleotides. The protective mechanism of tdh2 may involve preserving cell membrane permeability through regulation of ompU and ABC transporters and enhancing electron transfer efficiency via regulation of nhaR. The resulting reduction in ATP, DNA, and RNA synthesis—along with changes in membrane permeability and electron transfer due to decreased FMN—likely contributed to the reduced survival of the VP: △tdh2 strain. Meanwhile, the cells actively synthesized phospholipids to repair membrane damage, leading to increased levels of PS and PG. This study provides important insights into strategies for preventing and controlling food poisoning caused by tdh⁺ V. parahaemolyticus. Full article

Accurate gene expression quantification using reverse transcription quantitative PCR (RT-qPCR) requires stable reference genes (RGs) for reliable normalization. However, few studies have systematically identified RGs suitable for simultaneous high salt, alkaline, and high-temperature conditions. This study addresses this gap by evaluating the stability of eight candidate RGs in the anaerobic halophilic alkalithermophile Natranaerobius thermophilus JW/NM-WN-LF^T under combined salt, alkali, and thermal stresses. The stability of these candidate RGs was assessed using five statistical algorithms: Delta CT, geNorm, NormFinder, BestKeeper, and RefFinder. Results indicated that recA exhibited the highest expression stability across all tested conditions and proved adequate as a single RG for normalization in both RT-qPCR and droplet digital PCR (ddPCR) assays. Furthermore, recA alone or combined with other RGs (sigA, rsmH) effectively normalized the expression of seven stress-response genes (proX, opuAC, mnhE, nhaC, trkH, ducA, and pimT). This work represents the first systematic validation of RGs under polyextreme stress conditions, providing essential guidelines for future gene expression studies in extreme environments and aiding research on microbial adaptation mechanisms in halophilic, alkaliphilic, and thermophilic microorganisms. Full article

Pyrazolopyridines and pyrazolopyrimidines are 5:6 aza-fused N-heteroaromatic compounds (NHACs) comprising a pyrazole ring fused to a pyridine or pyrimidine ring. They exhibit dipolar behavior due to their π-excessive and π-deficient characteristics conferred by their five- and six-membered rings. These features favor their stability, reactivity, and structural diversity, offering numerous modular and functional derivatives (e.g., pyrazolo[1,2-a]pyridines, pyrazolo[1,5-a]pyrimidines, etc.). They have been utilized to obtain relevant chemicals in pharmaceuticals, photophysics, industry, and materials science; thus, their synthesis is highly desirable for discovering novel or improved applications. Therefore, this review focuses on recent advances in the synthesis and applications of these compounds, considering reports from the last decade (2015–2024), with particular emphasis on photophysics, as they contain dipolar 5:6 aza-fused rings as essential scaffolds for this purpose. Full article

A novel bi-layered scaffold, obtained via 3D printing and electrospinning, was designed to improve osteochondral region reconstruction. The upper electrospun membrane will act as a barrier against unwanted tissue infiltration, while the lower 3D-printed layer will provide a porous structure for tissue ingrowth. Graphene was integrated into the scaffold for its antibacterial properties, and the drug Osteogenon^® (OST) was added to promote bone tissue regeneration. The composite scaffolds were subjected to comprehensive physical, thermal, and mechanical evaluations. Additionally, their biological functionality was assessed by means of NHAC-kn cells. The 0.5% graphene addition to PCL significantly increased strain at break, enhancing the material ductility. GNP also acted as an effective nucleating agent, raising crystallization temperatures and supporting mineralization. The high surface area of graphene facilitated rapid apatite formation by attracting calcium and phosphate ions. This was confirmed by FTIR, µCT and SEM analyses, which highlighted the positive impact of graphene on mineral deposition. The synergistic interaction between graphene nanoplatelets and Osteogenon^® created a bioactive environment that enhanced cell adhesion and proliferation, and promoted superior apatite formation. These findings highlight the scaffold’s potential as a promising biomaterial for osteochondral repair and regenerative medicine. Full article

The nutrient, amino acid, and fatty acid compositions of Caulerpa lentillifera from various aquaculture regions were assessed to analyze their nutritional characteristics and potential for aquaculture development. The nutrient composition of C. lentillifera was determined according to the standard national nutrient determination methods of the Association of Official Analytical Chemists, and the following data were revealed. (1) The basic nutritional components of C. lentillifera were relatively more abundant in the three aquaculture areas in Guangdong Province. The crude protein content in C. lentillifera was measured at (8.70 ± 0.36)% and (18.57 ± 1.59)% for samples collected from the Dapeng and Daya areas, respectively. These values were significantly higher compared to those obtained from the Beihai, Dongshan, and Nha Trang regions (p < 0.05). Additionally, the crude lipid content of C. lentillifera from the Daya population was measured at (5.10 ± 1.59)%, which was significantly higher than that of samples from the Beihai, Dongshan, and Nha Trang areas (p < 0.05). Furthermore, the total sugar contents in C. lentillifera were quantified as (32.50 ± 4.22)% and (32.87 ± 2.59)% for samples from the Daya and Shanwei regions, respectively. These values were significantly greater (p < 0.05) compared to those observed in the other four populations. (2) The total amino acid (TAA) content of C. lentillifera ranged from 7.05% to 12.37%, with notable concentrations of the fresh amino acids aspartic acid (Asp) and glutamic acid (Glu). Significant variations in the TAA and essential amino acid (EAA) levels were observed among the cultivation regions (p < 0.05), with the Shanwei population exhibiting the highest TAA content of 12.37% and EAA content of 4.65%, surpassing all other populations except for Guangdong Province (p < 0.05). (3) The fatty acid composition analysis revealed that the total fatty acid (TFA) and unsaturated fatty acid (UFA) levels in the long-stemmed grape fern alga from Daya were 2.400% and 1.048%, respectively, and significantly greater than those in the other populations except for Dapeng (p < 0.05). These results imply that the nutritional quality of the Daya population of C. lentillifera is relatively high. C. lentillifera exhibits a palatable flavor profile, making it suitable for consumption and the development into high-quality seafood condiments, thereby contributing to the environmentally sustainable advancement of C. lentillifera aquaculture. Full article

We investigated the roles of low-density lipoprotein receptor-related protein (LRP) 4 and its ligand Agrin in the pathophysiology of cartilage degeneration. Immunohistochemical analysis of human normal articular cartilage and cartilage tissues from patients with osteoarthritis (OA) obtained during surgery of the knee joint showed marked LRP4 expression in the early stages of OA, which then decreased with cartilage degeneration, whereas Agrin was consistently increased with cartilage degeneration. In normal human articular chondrocytes (NHACs), mild cyclic tensile strain (CTS) (0.5 Hz, 5% elongation, 2 h) increased the expression of LRP4 and aggrecan (ACAN), while intense CTS (0.5 Hz, 10% elongation, 6 h) increased the expression of Agrin without affecting LRP4 expression. Treatment with recombinant human (rh) Agrin downregulated the mRNA expression of LRP4 and ACAN, but upregulated the expression of LRP5/6, SRY-box transcription factor 9 (SOX9), Runt-related transcription factor 2 (RUNX2), and a disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4). Immunocytochemistry and Western blot analysis showed that rhAgrin treatment upregulated the expression of β-catenin and SOX9. Agrin knockdown by siAGRN transfection partially reduced the nuclear protein expression of β-catenin, which was increased with intense CTS. LRP4 knockdown by siLRP4 transfection increased the expression of LRP5/6, SOX9, RUNX2, ADAMTS-4, and Agrin. These results suggested that intense CTS increases the expression of Agrin, which might interfere with the role of LRP4 in the inhibition of LRP5/6 and their downstream β-catenin signaling, leading to cartilage degeneration. Full article

Tillage, cover crops (CC) and nutrient amendments are regenerative agricultural practices (RAPs) which enhance desirable ecosystem services (DESs), including the beneficial nematode community structure (BNCS), soil organic matter (SOM), pH, and available nitrogen, and the Ferris et al. soil food web (SFW) model relates changes in the BNCS to biophysicochemical conditions generating DESs. However, the SFW model’s power to identify soil health conditions influencing DESs’ outcomes has been limited. We tested how tillage, winter rye CC, and 0, 112, or 224 kg N/ha from inorganic and compost sources affected the DESs after four years of corn production. The SOM and NO₃ was much greater in the no-till than the tilled soil, and the SOM in the 224 kg organic source, compared with the rest of the N rates, was significantly increased. The N recovery was not proportional to what was applied. The variable effects of the RAPs on the DESs suggest either changing or continuing treatments until suitable outcomes are achieved, all without knowing the source(s) of variability. The SFW model revealed primarily resource-limited and structured (Quadrant C) conditions, suggesting that (1) nutrient cycling needs biological activities and (2) the presence of a process-limiting factor may have contributed to the variable results. The impacts of the SFW model as a diagnostic tool are outlined. Full article

Background: The reparative regeneration of jawbone defects poses a significant challenge within the field of dentistry. Despite being the gold standard, autogenous bone materials are not without drawbacks, including a heightened risk of postoperative infections. Consequently, the development of innovative materials that can surpass the osteogenic capabilities of autologous bone has emerged as a pivotal area of research. Methods: Mesenchymal stem cells (MSCs), known for their multilineage differentiation potential, were isolated from human umbilical cords and transfected with miR-181a. The osteogenic differentiation of miR-181a/MSC was investigated. Then, physicochemical properties of miR-181a/MSC-loaded nano-hydroxyapatite (nHAC) scaffolds were characterized, and their efficacy and underlying mechanism in rat calvarial defect repair were explored. Results: miR-181a overexpression in MSCs significantly promoted osteogenic differentiation, as evidenced by increased alkaline phosphatase activity and expression of osteogenic markers. The miR-181a/MSC-loaded nHAC scaffolds exhibited favorable bioactivity and accelerated bone tissue repair and collagen secretion in vivo. Mechanistic studies reveal that miR-181a directly targeted the TP53/SLC7A11 pathway, inhibiting ferroptosis and enhancing the osteogenic capacity of MSCs. Conclusions: The study demonstrates that miR-181a/MSC-loaded nHAC scaffolds significantly enhance the repair of bone defects by promoting osteogenic differentiation and inhibiting ferroptosis. These findings provide novel insights into the molecular mechanisms regulating MSC osteogenesis and offer a promising therapeutic strategy for bone defect repair. Full article

This article reviews innovative diagnostic approaches for diabetic retinopathy as the prevalence of diabetes mellitus and its complications continue to escalate. Novel techniques focus on early disease detection. Technological innovations, such as teleophthalmology, smartphone-based photography, artificial intelligence with deep learning, or widefield photography, can enhance diagnostic accuracy and accelerate the treatment. The review highlights teleophthalmology and handheld photography as promising solutions for remote eye care. These methods revolutionize diabetic retinopathy screening, offering cost-effective and accessible solutions. However, the use of these techniques may be limited by insurance coverage in certain world regions. Ultra-widefield photography offers a comprehensive view of up to 80.0% of the retina in a single image, compared to the 34.0% coverage of the traditional seven-field imaging protocol. It allows retinal imaging without pupil dilation, especially for individuals with compromised mydriasis. However, they also have drawbacks, including high costs, artifacts from eyelashes, eyelid margins, and peripheral distortion. Recent advances in artificial intelligence and machine learning, particularly through convolutional neural networks, are revolutionizing diabetic retinopathy diagnostics, enhancing screening efficiency and accuracy. FDA-approved Artificial Intelligence-powered devices such as LumineticsCore™, EyeArt, and AEYE Diagnostic Screening demonstrate high sensitivity and specificity in diabetic retinopathy detection. While Artificial Intelligence offers the potential to improve patient outcomes and reduce treatment costs, challenges such as dataset biases, high initial costs, and cybersecurity risks must be considered to ensure safety and efficiency. Nanotechnology advancements further enhance diagnosis, offering highly branched polyethyleneimine particles with fluorescein sodium (PEI-NHAc-FS) for better fluorescein angiography or vanadium oxide-based metabolic fingerprinting for early detection. Full article