Search Results (25,619)

Exopolysaccharides (EPSs) represent versatile biopolymers finding diverse applications in food, pharmaceuticals, and bioremediation industries. Extremophiles, thriving under extreme environmental conditions, have emerged as a promising source of novel EPSs with better stability and bioactivity. The present work reviews the complex influence of various abiotic factors and bioprocess parameters such as temperature, pH, carbon and nitrogen sources, C/N ratios, and oxygen transfer dynamics on the production of EPSs from extremophilic microorganisms. Results underline the important role of temperature for structural and functional properties of EPSs, from the synthesis of cryoprotective polymers in psychrophiles to the production of thermostable EPSs in thermophiles under cold stress. The pH has an extensive effect on enzymatic activities: optimal neutral to slightly acidic conditions exist for most strains. Carbon sources determine not only the yield of EPSs but also its structural features, while nitrogen sources and C/N ratios regulate the balance between biomass production and polymer biosynthesis. Besides that, oxygen transfer limitations—which may happen in particularly viscous or saline media—are overtaken by optimized bioreactor configuration and stirring strategies. These findings are highly relevant to the development of tailored cultivation conditions enabling the maximization of EPS yields and adaptation of its properties to comply with industrial requirements. This study provides a framework for enhancing EPS production by leveraging the adaptive traits of extremophiles. This approach supports the sustainable use of biopolymers, advances fermentation production processes, and helps uncover the underlying mechanisms involved. Full article

In order to detail the antiplasmodial effects of quinones (Q) and nitroaromatic compounds (ArNO₂), we investigated their reduction mechanism by Plasmodium falciparum flavoenzyme type II NADH:ubiquinone oxidoreductase (PfNDH2). The reactivity of Q and ArNO₂ (n = 29) follows a common trend and exhibits a parabolic dependence on their single-electron reduction potential ($E_7^1$), albeit with significantly scattered data. The reactivity of quinones with similar $E_7^1$ values increases with their lipophilicity. Quinones are reduced by PfNDH2 in a two-electron way, but ArNO₂ are reduced in a single-electron way. The inhibition studies using NAD⁺ and ADP-ribose showed that quinones oxidize the complexes of reduced enzyme with NADH and NAD⁺. This suggests that, as in the case of other NDH2s, quinones and the nicotinamide ring of NAD(H) bind at separate sites. A scheme of PfNDH2 catalysis is proposed, consistent with both the observed ‘ping-pong’ mechanism and the presence of two substrate binding sites. Molecular docking showed that Q and ArNO₂ bind in a similar manner and that lipophilic quinones have a higher affinity for the binding site. One may expect that PfNDH2 can be partially responsible for the previously observed enhanced antiplasmodial activity of aziridinylbenzoquinones caused by their two-electron reduction, as well as for the redox cycling and oxidative stress-type action of ArNO₂. Full article

The purpose of this study is to determine the plastic wear of the cartridge filter casing 01WTKF (Wolftechnik Filtersysteme GmbH & Co. KG, Weil der Stadt, Germany) when exposed to sand, sediment, and ice at temperatures below 0 °C, both in laboratory and field conditions. Furthermore, this study aims to discuss whether previous studies conducted with the model 01WTKF may suffer significant errors due to abrasion. The freshwater samples were collected in Finnmark, Norway. These samples were filtered using a cartridge filtration method and the 01WTKF filter casing, which features lids made of polypropylene (PP) and bottom parts made of styrene–acrylonitrile copolymer (SAN) or PP. The samples were analyzed for microplastic (MP) cross-contamination by comparing the results of the model 01WTKF to those of the stainless-steel-based model 01WTGD. Laboratory and environmental samples were examined using FT-IR spectroscopy. The results indicate that wear occurs for ice, sand, and sediment. Abrasion significantly increased the overall PP concentration in the environmental samples, introducing an error of 858 ± 516 N m⁻³ MPs to 2453 ± 92 N m⁻³ MPs. By contrast, no wear was detected for the SAN-based bottom part. For the PP-based lids, only 92 ± 83 N m⁻³ MPs were identified. Therefore, the use of PP-based bottom parts and lids is not recommended at temperatures below 0 °C. Additionally, studies utilizing the model 01WTKF should be reviewed and re-evaluated to ensure the accuracy of the obtained data. Full article

The Vilsmeier–Haack reaction is a convenient method for the formylation of electron-rich aromatic compounds. However, this interaction sometimes gives specific side products. We report the isolation and structural characterization of a novel compound (Z)-1-(3,5-dichloro-2-pyrrolylidene)-N,N-dimethylmethanamine obtained as a side product during the formylation of 2-chloropyrrole. The product was characterized using NMR spectroscopy and X-ray crystallography. Full article

This study aims to develop a novel use of baker’s yeast in biosorption as a sustainable metal recovery process for cost-effective and practical applications in recovering copper and zinc from waste gravity-thickened sludge generated at livestock wastewater treatment facilities. The supernatant of the acid-extracted product was separated from the residues through centrifugation. To ensure cost efficiency, the supernatant was treated with 2N acetic acid for 24 h, with the addition of hydrogen peroxide, and used for the biosorption experiments. The filtrated supernatant was adjusted to various pH values (4.5, 5.0, and 5.5) to explore the effects of acidity on the subsequent biosorption of extracted zinc and copper by baker’s yeast. A diluted molasses solution was added to the filtrate as a carbon source to support yeast growth during the 4 h biosorption experiments. The results revealed that the removal efficiency of zinc from the filtrate by baker’s yeast was 97.3%, while the removal efficiency for copper was about 48.8% at pH 5.5 with a reaction time of 4 h. In summary, this combined approach is expected to reduce and recycle heavy metals in livestock sludge. Acetic acid with hydrogen peroxide can extract copper and zinc from the sludge, and baker’s yeast can absorb both metals from the filtrate at pH 5.5 in a 4 h reaction time. This technological innovation has the potential to transform waste management practices in the livestock industry, contributing to resource recovery and environmental sustainability. Full article

Background/Objectives: Due to post-surgical discomfort in kidney transplant recipients and donors as well as opioids’ multiple side effects, alternative analgesic methods are required in renal transplant surgeries. This study aimed to evaluate the analgesic effect of the transversus abdominis plane (TAP) block versus no-block controls in kidney transplantation patients. Methods: We conducted a meta-analysis with a trial sequential analysis (TSA) of randomized controlled trials (RCTs). We searched for relevant articles in PubMed, Scopus, and the Cochrane Library published before December 2023. Protocol registration: doi.org/10.17605/OSF.IO/PMZJ4. Results: A total of 11 RCTs were included in the meta-analysis. The TAP block group had lower pain intensity on postoperative day 1 (mean difference, MD = −0.65 [−0.88, −0.42]; p < 0.00001) than the control group. However, the heterogeneity among the included studies was considerable (I² = 93%). Subgroup meta-analysis and TSA revealed a significant pain reduction at 24 h postoperatively in donors (MD = −0.70 [−1.16, −0.24]; p = 0.003); heterogeneity was substantial (I² = 67%). The TAP block group also had lower overall morphine consumption within 24 h (MD = −4.82 [−7.87, −1.77]; p = 0.002) and cumulative 24 h morphine use (MD = −14.13 [−23.64, −4.63]; p = 0.004); however, heterogeneity was considerable (I² = 98% in both cases). The time to first analgesia (hours) was significantly longer in the TAP block group (MD = 5.92 h [3.63, 8.22]; p < 0.00001, n = 3). There was no significant difference between the groups in postoperative nausea and vomiting (risk ratio, RR = 0.91 [0.49, 1.71]; p = 0.78). Conclusions: TAP block can lower pain intensity and reduce morphine consumption on the first postoperative day in patients undergoing renal transplantation. Pain reduction is especially notable in the subgroup of donors, but the benefits reported are minimum and certainly not clinically relevant. Larger, well-powered RCTs are warranted to confirm these results and evaluate the effect of TAP block in the subgroup of recipients. Full article

Nanomaterials and sensors play an important role in modern technologies, including medical diagnostics and biochemical research. This work presents the possibility of using o-Phthaldialdehyde (OPA) in combination with 3-mercaptopropyltriethoxysilane (MPTES) to develop a dopamine-responsive sensor. During the experiment, these materials were used at different pH and ratios to determine the optimal parameters for obtaining high fluorescence intensity of the reaction product. The data obtained demonstrate a linear relationship between the fluorescence response (λ_ex/λ_em = 340/460 nm) of OPA/MPTES and dopamine concentration in the range of 0.1–3.0 µM at a pH of 8, and the detection limit was 8.7 nM. The obtained results confirm the potential of OPA/MPTES as a sensing component for the detection of dopamine. Full article

Biochar application as a soil amendment is gaining attention as a stable, long-term carbon sequestration strategy for the mitigation of climate change. However, biochar applied to the soil may increase soil carbon efflux. This study aimed to determine the long-term (8 years) effects of biochar application to the forest floor on soil carbon effluxes (soil respiration [SR] and heterotrophic respiration [HR]) in a warm–temperate oak forest. Biochar was applied at the rate of 0, 5, or 10 Mg ha⁻¹ to 20 m × 20 m plots (n = 4). The SR and HR rates were determined using the closed chamber method and the trenching method. The annual SR tended to increase over 8 years following biochar application, whereas a significant increase in the annual HR (+31%–37%) was observed in the short term (<3 years). The increased HR likely included CO₂ emissions from the decomposition of the labile fraction of biochar carbon and from the microbial decomposition of the original soil organic matter stimulated through changes in the soil physicochemical environment, such as soil moisture and pH. The results suggest that a short-term increase in HR should be considered in the evaluation of carbon sequestration in response to biochar addition to forest ecosystems. Full article

The objective of this study was to deduce the effect of exogenous supplementation of progesterone as an intramuscular injection at the time of artificial insemination (AI) on time of ovulation and conception rate in lactating Murrah buffaloes. A total of 30 buffaloes were included in the experiment and randomly divided into two groups (Treatment, n = 13 and Control, n = 17). Only those buffaloes which were in heat according to visual observation and had clear vaginal discharge, good uterine tone and a large follicle (>12 mm on ultrasound scanning) were reported. Ultrasound scanning was carried out at 6 h intervals after insemination until ovulation. The results revealed that significantly higher numbers of buffaloes ovulated within 24 h post AI in the control group (82.4%) as compared to only 15.4% in the treatment group. In the treatment group, 53.8% of ovulations occurred after 24 h post AI, whereas in the control group only 11.8% of ovulations occurred after 24 h post AI. Up to 96 h post AI, 30.8% of buffaloes in the treatment group and only 5.9% of buffaloes in the control group remained anovulatory. No significant difference was found in CL size between the treatment (226.5 ± 17.4 mm²) and control (238.9 ± 7.9 mm²) groups. Following insemination, 52.9% of buffaloes in the control group conceived, whereas in the treatment group, only 38.5% of buffaloes conceived. Full article

Background: The worldwide increase in the prevalence of childhood obesity necessitates effective prevention and treatment strategies. Clinical practice guidelines (CPGs) offer guidance, but significant heterogeneity or lack of practical application exists in their recommendations. The purpose of the present study is to provide an expert, comprehensive, and comparative analysis of gaps in current CPGs for the prevention and treatment of obesity in children and adolescents. Results: A total of 14 CPGs were identified, focusing on childhood obesity prevention (n = 11), treatment (n = 9), or both (n = 6). Prevention CPGs generally recommend body mass index (BMI) assessment, but specific measurement frequency is often absent. While some provide age-specific dietary recommendations, graphical tools are lacking. Recommendations for increased physical activity and reduced screen time are common, but age-stratified guidance is deficient. Furthermore, recommendations regarding mental health and sleep are notably absent. Treatment CPGs utilize BMI for obesity diagnosis, but inconsistencies in cut-off points persist. Comorbidity assessment is generally recommended, yet age-specific guidance remains lacking. Dietary recommendations are present in most CPGs, but many lack detailed specifications (e.g., meal frequency, portion sizes, macronutrient distribution, age-appropriate examples). Most CPGs advocate for 60 min of daily physical activity and limit screen time to 2 h per day. Recommendations concerning sleep are consistently absent. While parental involvement is acknowledged, specific guidance for active participation in prevention and treatment is deficient. Pharmacological treatment options are frequently outdated, and surgical intervention is reserved for exceptional cases of severe obesity. Conclusions: Standardizing BMI cut-off points and defining age groups across CPGs would improve consistency and comparability in the diagnosis, prevention, and treatment of childhood obesity. Tailoring recommendations for diet, physical activity, sedentary behavior, and sleep to specific age groups would ensure developmentally appropriate interventions. A stronger emphasis on early prevention strategies is needed to address the root causes of obesity. Clear guidance for parents and families would facilitate their active engagement in prevention and treatment. Up-to-date information regarding pharmacological and surgical treatments is imperative. Full article

This study assessed the changes in the mechanical and surface properties of the transition zone in multilayered translucent monolithic zirconia subjected to long-term hydrothermal aging. A total of 360 disk-shaped specimens (diameter: 15.0 mm; thickness: 1.2 mm) were prepared using conventional (3Y-TZP in LT; ZL, 4Y-TZP in MT; ZM) and multilayered translucent zirconia (5Y-TZP in MT Multi; ZT, 3Y/5Y-TZP in Prime; ZP) among IPS e.max ZirCAD blocks. Specimens were divided into three groups (n = 30) and aged in the autoclave at 134 °C under 0.2 MPa for 0 h (control group), 5 h (first aged group), and 10 h (second aged group). The mechanical and surface properties of the transition zone in the multilayered translucent zirconia were investigated, followed by statistical analysis (α = 0.05). Before and after aging, ZL (1102.64 ± 41.37 MPa) and ZP (1014.71 ± 139.86 MPa) showed the highest biaxial flexural strength (BFS); ZL showed the highest Weibull modulus (31.46) and characteristic strength (1121.63 MPa); and ZT exhibited the highest nanoindentation hardness (20.40 ± 1.80 GPa) and Young’s modulus (284.90 ± 20.07 GPa). After aging, ZL (116.75 ± 9.80 nm) exhibited the highest surface roughness (Ra); the monoclinic phase contents in ZL and ZP increased; and surface uplifts, microcracks, and irregular defects caused by phase transformation appeared on ZL and ZP surfaces. The 3Y/5Y-TZP transition zone exhibited flexural strength, Vickers hardness, phase distribution changes, and surface microstructure changes similar to those of 3Y-TZP before and after aging; however, the surface roughness was lower than that of 3Y-TZP and higher than those of 4Y-TZP and 5Y-TZP after aging. The mechanical and surface characteristics, excluding BFS and Vickers hardness, were influenced by the yttrium oxide content in each zone and the aging process. Full article

The [3+2] cycloaddition chemistry of (2S)-5-methylene-2-t-butyl-1,3-dioxolan-4-one, derived from lactic acid, has been examined, and spiro adducts have been obtained with benzonitrile oxide, acetonitrile oxide, diazomethane and diphenyldiazomethane. The structure and absolute stereochemistry of the benzonitrile oxide adduct has been confirmed by X-ray diffraction, and all the adducts have been fully characterised by ¹H and ¹³C NMR. Attempted cycloaddition with a nitrile sulfide, a nitrile imine and azides failed. Pyrolysis results in a range of novel gas-phase reactions, with the nitrile oxide adducts giving pivalaldehyde, CO₂, the nitrile and ketene, the diazomethane adduct losing only N₂ to give a cyclopropane-fused dioxolanone, and the diphenylcyclopropane derived from diphenyldiazomethane giving mainly benzophenone in a sequence involving the loss of pivalaldehyde and methyleneketene. Full article

Wetland ecosystems are essential to the global carbon cycle, and they contribute significantly to carbon storage and regulation. While existing studies have explored the individual effects of the water depth, vegetation, and soil properties on the soil organic carbon (SOC) components, a comprehensive study of the interactions between these factors is still lacking, particularly regarding their collective impact on the composition of the SOC in wetland soils. This paper focused on the Huixian Wetland in the Li River Basin. The variations in the SOC and its fractions, namely dissolved organic carbon, microbial biomass carbon, light fraction organic carbon, and mineral-associated organic carbon, under different water depths and vegetation conditions were examined. Additionally, the effects of the water depth, vegetation, and soil properties (pH and bulk density, total phosphorus (TP), total nitrogen (TN), ammonium nitrogen (NH₄-N), and nitrate nitrogen (NO₃-N)) on the changes in the SOC and its components were quantified. Specific water depth–vegetation combinations favor SOC accumulation, with Cladium chinense at a water depth of 20 cm and Phragmites communis at 40 cm exhibiting a higher biomass and higher SOC content. The SOC components were significantly and positively correlated with plant biomass, TP, TN, and NH₄-N. The coupling of water depth, vegetation, and soil properties had a significant effect on the SOC components, with the coupling of water depth, vegetation, and soil properties contributing 74.4% of the variation in the SOC fractions. Among them, water depth, plant biomass, and soil properties explained 7.8%, 7.3%, and 6.4% of the changes, respectively, and their interactions explained 25.6% of the changes. The coupling of the three significantly influenced the changes in the SOC components. Optimal water level management and the strategic planting of wetland vegetation can enhance the carbon storage capacity and increase the SOC content. This research offers valuable insights for effectively managing wetland carbon sinks and soil carbon reserves. Full article

The association of an aromatic ring with an N-H-unsubstituted imine generates families of compounds that have been little studied until now except when the ring is a phenyl group. Recently, such imines substituted by a furan or thiophene group have been synthesized. This work reports a similar study where a pyrrole or pyridine ring is directly linked to an N-unsubstituted aldimine or ketimine group in order to isolate such compounds and to open the way to the knowledge of their physicochemical properties. The lower volatility of pyrrole and pyridine derivatives compared to aryl, furan, or thiophene derivatives greatly increases the difficulty of the synthesis and isolation of these kinetically unstable compounds. Full article

The concurrent preservation of structural integrity and improvement of electrical conductivity in FeP₂ anodes presents a persistent challenge. Herein, FeP₂ nanoparticles embedded within a 3D N-doped honeycomb-like carbon framework composite (FeP₂@NHC) are synthesized through a phosphorization process with a honeycomb-like Fe₃C@NHC as a precursor. The in situ incorporation of FeP₂ nanoparticles into the 3D carbon matrix effectively restrains the aggregation, pulverization, and stripping of material during cycling, and significantly enhances reaction kinetics and structural stability, achieving a superior electrochemical performance. Specifically, FeP₂@NHC electrodes demonstrate remarkable reversible capacity (1433.9 mA h g⁻¹ at 0.1 A g⁻¹), excellent rate-capability (399.9 mA h g⁻¹ at 10 A g⁻¹), and ultra-long cycle life (631.5 mA h g⁻¹ after 1000 cycles at 2 A g⁻¹). Moreover, XRD analysis reveals that iron-rich Fe₃C and Fe₃O₄ precursors can react with NaH₂PO₂ to form FeP₂ and FeP, respectively. This study offers a rational and practical strategy for designing other phosphorus-rich metal phosphide anode materials. Full article