Search Results (5,449)

Plantations left for natural succession play a significant role in Tropical Rainforest National Parks. Studying the succession and restoration of plantations is crucial for achieving a park’s authenticity and integrity, as well as for maximizing its ecological functions. However, the changes in vegetation and soil properties during the natural succession of these decommissioned plantations remain unclear. In this study, we examined rubber [(Hevea brasiliensis (Willd. Ex A. Juss.) Muell. Arg] plantations in the Yinggeling area of the National Park of Hainan Tropical Rainforest. We used community surveys, field sampling, and soil property analyses to investigate the species richness, diversity, and species composition of the aboveground plant communities during three succession periods of rubber plantations left for natural succession, including 0 years (ZY), 3 years (TY), and 7 years (SY). The soil pH, total organic carbon, total nitrogen, total phosphorus, available phosphorus, nitrate nitrogen, ammonium nitrogen, and total potassium contents in the three succession periods were analyzed. These results showed that there were 92 species of understory plants in the decommissioned rubber plantations, belonging to 72 genera in 39 families. The highest number of understory plant species was found in the plantations with 3 years of natural succession, totaling 66 species from 49 genera in 29 families. The number of families, genera, and species followed the pattern TY > SY > ZY. The Margalef richness index (F), Simpson index (D), and Shannon–Wiener index (H) of understory plants in the 0-year succession plantations were significantly lower than those in the 3-year and 7-year succession plantations. However, there was no significant difference in the Pielou (EH) index among the succession gradients. The soil pH, nitrate nitrogen (NO3--N), and available phosphorus (AP) in the 0-year succession plantations were significantly higher than those in the 3-year and 7-year succession plantations. There were no significant differences in soil total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC), and ammonium nitrogen (NH4+-N) across the three succession gradients. The soil total potassium (TK) in the 3-year succession plantations was significantly higher than that in the 0-year and 7-year succession plantations. Soil available phosphorus and total phosphorus (TP) were positively correlated with the Margalef index, Simpson index, Shannon–Wiener index, and Pielou index. The recovery rate of understory vegetation in decommissioned rubber plantations was faster than that of the soil. This indicates that the construction of the National Park of Hainan Tropical Rainforest has significantly promoted the recovery of the number of plant species and plant species diversity that have been left from rubber plantation operations. These findings not only deepen our understanding of soil property changes during the vegetation succession of artificial forests, particularly rubber plantations, but they also hold significant implications for guiding tropical forest management and sustainable development. Full article

This study presents an evaluation of the CHIMBO modeling chain applied to the Italian domain, specifically focusing on the Po Valley subdomain over the one-year period of 2019. The comparison between simulated and observed data indicates that the performance of the CHIMBO model aligns well with existing literature on other state-of-the-art models. The results demonstrate that the CHIMBO chain is particularly effective for regional-scale quantitative assessments of pollutant distribution, comparable to that of CAMS ensemble models. The analysis of key chemical species in particulate matter reveals that the CHIMBO model accurately represents the average concentrations of organic and elemental carbon, as well as secondary inorganic compounds (sulfate, nitrate, and ammonium), particularly at background monitoring stations in the flat terrain of the Po Valley, with the exception of Aosta, a city located at about 500 m asl. However, seasonal discrepancies were identified, especially during winter months, when significant underestimations were observed for several species, including elemental and organic carbon, predominantly at background sites. These underestimations are likely attributed to various factors: (i) inadequate estimations of primary emissions, particularly from domestic heating; (ii) the limited effectiveness of secondary formation processes under winter conditions characterized by low photochemical activity and high humidity; and (iii) excessive dilution of pollutants during calm wind conditions due to overestimation of wind intensity. In conclusion, while the CHIMBO modeling chain serves as a robust tool for mesoscale atmospheric composition investigations, limitations persist related to emissions inventories and meteorological parameters, which remain critical drivers of atmospheric processes. Full article

There is a growing recognition that food waste (FW) comprises a significant amount of unused energy. Indeed, FW shows great potential to produce methane (CH₄)-rich biogas via an anaerobic digestion (AD) process. Nevertheless, to ensure high AD process performance, deepening the knowledge of FW characteristics is required. Furthermore, the biogas yield is strongly influenced by several operational parameters. Taking into account the above, in the current study, based on the data in the literature, the physicochemical parameters of FW generated throughout the world are presented and discussed. In addition, the performance profile of the single-stage anaerobic mono-digestion process with the use of FW as a feedstock was investigated. The performed analysis clearly demonstrated that FW is characterized by significant variations in several parameters, such as pH, the total solid (TS) and volatile solid (VS) contents, the volatile solids to total solids ratio (VS/TS), soluble chemical oxygen demand (sCOD), the concentrations of VFAs and ammonium nitrogen (NH₄⁺-N), and the carbon-to-nitrogen ratio (C/N). Moreover, it was shown that the selected operational parameters, such as temperature, pH, the ratio of food waste to inoculum (I) (FW/I), and the organic loading rate (OLR), may have the most significant impact on the performance of the single-stage anaerobic mono-digestion process. In addition, it was found that most of the experimental investigations presented in the literature were conducted on a laboratory scale. Hence, in future research, more effort should be made to determine the biogas yield with the use of full-scale systems. To summarize, it should be clearly highlighted that the analysis presented in this study may have important implications for the management and application of FW as feedstock for an anaerobic mono-digestion process on an industrial scale. Full article

Paddy fields are important anthropogenic emission sources of methane (CH₄). However, it is not clear how rice root development and rhizosphere soil properties affect CH₄ emissions. Therefore, we selected rice varieties with similar growth periods but different root traits in the local area. We measured CH₄ emission fluxes, cumulative CH₄ emissions, root dry weight, root length, and the dissolved organic carbon (DOC), microbial biomass carbon (MBC), redox potential (Eh), ammonium nitrogen (NH4+–N), and nitrate nitrogen (NO3−–N) contents in rhizosphere soil. Methanogens and methanotrophs are crucial factors influencing CH₄ emissions; thus, their abundance and community composition were also assessed. The result showed that CH₄ fluxes of each rice variety reached the peak at tillering stage and jointing-booting stage. The CH₄ emissions in tillering stage were the largest in each growth period. CH₄ emissions had negative correlations with root length, root dry weight, Eh NO3−–N, methanotroph abundance, and the pmoA/mcrA ratio, and positive correlations with NH4+–N, MBC, DOC, and methanogen abundance. Path analysis confirmed methanogens and methanotrophs as direct influences on CH₄ emissions. Root development and rhizosphere soil properties affect CH₄ emissions indirectly through these microbes. This study suggests that choosing rice varieties with good root systems and managing the rhizosphere soil can effectively reduce CH₄ emissions. Full article

Nitrogen (N) fertilizer is routinely applied in highbush blueberry (Vaccinium corymbosum L.) production. The recommended N fertilizer rate increases as the plants mature, and is usually determined based on regional growing conditions. However, the effects of N fertilizer rates and application methods over the long term remain poorly understood. In this study, ammonium sulfate was applied as an N source at the recommended rate (100%), which corresponds to a maximum of 155 kg N ha⁻¹ for plants older than eight years, along with higher rates at 150% and 200% of the recommended level, as well as a control treatment of no N. Treatments were applied to the blueberry cultivar ‘Duke’ as either broadcast (BROAD) or fertigation (FERT), and impacts were analyzed after 12 and 13 years of treatment. In the 14th year, the 100% N rate was uniformly applied as BROAD across all plants to separate the effects of different N rates from those caused by long-term soil condition changes. The BROAD treatment at the 100% N rate achieved the highest yield, and the FERT treatment at 200% resulted in the lowest yield in the 12th year, suggesting that excessive N rates can reduce fruit yield. However, no significant yield differences were observed in the 13th year. Higher N rates were associated with reduced titratable acidity in fruits and fewer flower buds. The soil pH declined across all N treatments, with the FERT at 200% showing the most significant reduction. All N treatments generally increased soil electrical conductivity (EC). High N rates also decreased plant accumulation of magnesium, calcium, and copper, with the latter reaching deficiency levels. These findings emphasize the importance of adhering to recommended N application rates and adjusting soil pH and EC to mitigate the adverse effects of prolonged N treatments. Full article

The excessive mineralization of organic molecules during anaerobic fermentation increases the availability of nitrogen and carbon. For this reason, the development of downstream processing technologies is required to better manage ammonia and carbon dioxide emissions during the storage and land application of the resulting soil organic amendment. The present work investigated classical distillation as a technology for valorizing ammoniacal nitrogen (NH₄⁺-N) in anaerobic digestate. The results implied that the direct isolation of ammonium bicarbonate (NH₄HCO₃) was possible when applying the reactive distillation to the food waste digestate (FWD) with a high content of NH₄⁺-N, while the addition of antifoam to the agrowaste digestate (AWD) was necessary to be able to produce an aqueous solution of NH₄HCO₃ as the distillate. The reason was that the extraction of NH₄HCO₃ from the AWD required a higher temperature (>95 °C) and duration (i.e., steady state in batch operation) than the recovery of the inorganic fertilizer from the FWD. The titration method, when applied to the depleted digestate, offered the quickest way of monitoring the reactive distillation because the buffer capacity of the distillate was much higher. The isolation of NH₄HCO₃ from the FWD was attained in a transient mode at a temperature below 90 °C (i.e., while heating up to reach the desired distillation temperature or cooling down once the batch distillation was finished). For the operating conditions to be regarded as techno-economically feasible, they should be attained in the anaerobic digestion plant by integrating the heat harvested from the engines, which convert the biogas into electricity. Full article

Objective: To establish and validate an LC-MS/MS method for the simultaneous determination of curcumin (CUR) as well as its glucuronide conjugate (COG) and sulfate conjugate (COS) in rat plasma. The method was employed to evaluate and compare the pharmacokinetic behaviors of curcumin following oral and intratracheal administration in rats. Methods: Rat plasma samples were separated by chromatography on a C18 column after protein precipitation with acetonitrile. Gradient elution with a mobile phase of 0.5 mM ammonium acetate in acetonitrile was utilized. Mass spectrometry detection incorporated an electrospray ionization (ESI) source, multiple reaction monitoring (MRM), and dual-mode (positive and negative) scanning for quantitative analysis. A total of 12 SD rats were randomly divided into two groups and were orally (20 mg/kg) or intratracheally (10 mg/kg) administrated curcumin, respectively. CUR, COG, and COS concentrations in plasma were measured to assess pharmacokinetic disparities. Results: The method demonstrated linearity within the ranges of 2–400 ng/mL for CUR and COS and 5–1000 ng/mL for COG. Intratracheal administration significantly elevated CUR plasma concentrations compared to oral administration. The exposure of COG was higher than COS following oral administration. Conversely, intratracheal administration resulted in markedly higher COS exposure, with no significant difference in COG exposure after dose normalization between oral and inhalation routes. Conclusions: The established LC-MS/MS method provides a reliable tool for the simultaneous measurement of CUR, COG, and COS in rat plasma, facilitating preclinical pharmacokinetic investigations. The study reveals distinct pharmacokinetic profiles for CUR following oral versus intratracheal administration, suggesting that inhalation may offer superior therapeutic efficacy. Full article

Antibacterial coatings based on quaternary ammonium compounds (QACs) have been widely investigated in controlled release applications. Quaternary ammonium compounds are low-cost and easily accessible disinfectants that have been extensively used, especially after the COVID-19 outbreak. There has been a growing interest in developing a clearer understanding of various aspects that need to be taken into account for the design of quaternary ammonium compounds to be used in the biomedical field. In this contribution, we outline the mechanism of action of those materials as well as the key design parameters associated with their structure and antibacterial activity. Moreover, emphasis has been placed on the type of antibacterial coatings based on QACs and their applications in the biomedical field. A brief outlook on future research guidelines for the development of dual-function antibacterial coatings is also discussed. Full article

The outbreak of epidemics such as African swine fever has intensified the use of disinfectants in pig farms, resulting in an increasing residual concentration of disinfectants in environmental media; however, the high-frequency excessive use of disinfectants that damage pig farm manure anaerobic fermentation systems and their mechanisms has not attracted enough attention. Especially, the complex effects of residual disinfectants on anaerobic fermentation systems for pig manure remain poorly understood, thus impeding the application of disinfectants in practical anaerobic fermentation systems. Herein, we explored the effects of glutaraldehyde disinfectant on methane production, effluent physicochemical indices, and microbial communities in a fully automated methanogenic potential test system (AMPTSII). The results show that adding glutaraldehyde led to remarkable alterations in methane production, chemical oxygen demand (COD), volatile solids (VS), and polysaccharide and phosphorus concentrations. During the anaerobic process, the production of methane displayed a notable decrease of 5.0–98% in all glutaraldehyde treatments, and the trend was especially apparent for treatments containing high levels of glutaraldehyde. Comparisons of the effluent quality showed that in the presence of 0.002–0.04% glutaraldehyde, the COD and total phosphorus (TP) increased by 12–310% and 15–27%, respectively. Moreover, the addition of 0.01–0.08% glutaraldehyde decreased the ammonium (NH₄⁺-N) concentration and VS degradation rate by 7.7–15% and 4.9–26.2%. Furthermore, microbiological analysis showed that the glutaraldehyde treatments had adverse effects on the microbial community. Notably, certain functional bacteria were restrained, as highlighted by the decreases in relative abundance and microbial diversity by 1.3–17% and 0.06–21%, respectively. This study provides a theoretical basis for the rational use of disinfectants in anaerobic fermentation systems. Full article

Aiming at the problem of excessive swelling of conventional microspheres for oilfield use, a novel amphiphilic polymerizable crosslinker (AE) was synthesized by quaternary ammonium modification of an unstable crosslinker (AE) using acrylamide, 2-acrylamido-2-methylpropanesulfonic acid as the monomers, N,N′-methylene bisacrylamide as the stabilizing crosslinker, ammonium peroxysulfate and sodium bisulfite as the initiator, and water as the solvent by using a reversed microemulsion method. Double-networked nanomicrospheres were prepared. The preparation conditions of the microspheres were optimized by the surface response method, focusing on the effects of the initiator addition and reaction temperature, and total crosslinker addition on the formation of nanomicrospheres. The samples were characterized by FTIR, TGA, laser particle sizer, and SEM to evaluate the retarded expansion performance and the modulation drive performance. The results showed that the optimal conditions for the preparation of microspheres were m(oil phase):m(water phase) = 3:2, stirring speed of 550 r/min, total crosslinking agent dosage of 0.6% (based on the total mass of monomers, hereinafter the same), initiator dosage of 0.30%, reaction temperature of 45 °C, and reaction time of 4 h. Compared with the conventional polymer microsphere PAM, PAE was slow-expanded for 45 d at 60 °C, and the expansion multiplier was about 16 times, with slow-expansion characteristics; the blocking rate of PAE reached 98.3%, the oil repulsion rate was 73.11%, and the increase in the recovery rate could be up to 11.23%. In this paper, a new type of nanomicrosphere material is investigated to realize the efficient implementation of oil field conditioning and driving. Full article

Salmonella Infantis poses a significant challenge in poultry production due to its persistence and resistance to disinfectants. This study investigated the survival of the S. Infantis strain on different surfaces and evaluated the efficacy of disinfectants in both preventing and treating biofilms. The survival of the tested S. Infantis strain was assessed on plastic and stainless steel surfaces after 24 and 48 h. The minimum inhibitory concentrations (MICs) of five disinfectants were determined, and their antiadhesion effectiveness was evaluated using crystal violet. The efficacy of biofilm treatment was evaluated by cell culturability. The results showed that the adhesion of S. Infantis was significantly higher on the plastic surface. The disinfectants were effective at reducing biofilm formation only within the first 24 h. Fresh solutions of disinfectants based on quaternary ammonium compounds exhibited the highest antimicrobial efficacy, while chlorocresol was the most effective for both the prevention and treatment of biofilms. The study results suggest that the presence of plastic surfaces may contribute to the dissemination of Salmonella. Additionally, the effectiveness of disinfectants varied based on storage conditions and contact time, while biofilms demonstrated reduced susceptibility compared to planktonic cells. However, given the laboratory scale of this study, further validation on a commercial scale is necessary to confirm these findings. Full article

Nowadays, incorporating quaternary ammonium groups into polymers is one of the most promising strategies for preparing antimicrobial biomaterials for general applications. The main objective of this work was to evaluate the effect of different concentrations of antimicrobial quaternary polymers in gelatin- and starch-based films for the development of active materials intended for applications in food packaging and medical fields. Two antimicrobial biobased polymers, called MeFPIAx (MeFPIA1 and MeFPIA2), were previously synthesized through the radical polymerization of itaconic acid (IA), followed by their subsequent functionalization and modification. Both polymers were incorporated into a new blend of gelatin and starch (15% w/w, 4:1 mass ratio), using glycerol (30% w/w) as a plasticizer. Films were prepared using the casting technique from aqueous dispersions of the polymers and their structure was characterized by Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR). The findings of this study showed the addition of MeFPIAx had a significant effect (p < 0.05), resulting in films with higher tensile strength (TS) and a higher Young’s modulus (YM), with values close to 20 MPa and exceeding 250 MPa, respectively. On the other hand, elongation at break (EB) values lower than 80% were obtained. Additionally, the swelling was reduced from ~400% to 100% and a reduction in water vapor permeability (P_w) was observed, thanks to the increased interaction between the polymeric chains. Differential scanning calorimetry (DSC) scans showed that the addition of MeFPIAx increased the glass transition temperatures (T_g) from 29 °C to 65 °C. Furthermore, thermogravimetry analysis (TGA) indicated an increase in the initial degradation temperatures, suggesting that the films were more thermally resistant. Finally, the films exhibited slight antioxidant activity but significant antimicrobial activity, achieving bacterial reduction values greater than 70% with the incorporation of MeFPIAx polymers against Gram-positive Staphylococcus aureus. Full article

Water-soluble inorganic ions (WSIIs) can increase the hygroscopicity of aerosols, which will transform aerosols into larger sizes and reduce visibility by enhancing light scattering. To explore the characteristics of WSII concentrations and their impacts on visibility in a coastal airport, in this study, PM_1.0 samples at two monitoring sites (including airport site and background site) were collect in spring and summer, and 12 species of ions were detected. In general, secondary water-soluble inorganic ions (SNA, including SO42−, NO3− and NH4+) and Ca2+ were the dominant WSIIs in PM_1.0, contributing about 89% to 95% of the total measured ions. The continental contributions of SO42−, K+, and Ca2+ accounted for more than 60% during the whole period, while Na⁺ and Cl− were mainly from marine sources. The source identification showed that airport emissions were a major source at the sampling site and significantly contributed to the levels of sulfate, nitrate, and ammonium. Agricultural activities were the dominant sources impacting visibility in spring, while airport emissions and secondary inorganic aerosols were the main components affecting visibility in summer. Therefore, improving atmospheric visibility in coastal airport areas should focus on reducing the precursors of secondary particulates and reducing biomass-burning activities. Full article

Dental caries are treated using dental composite restorative materials (DCRM). However, commercial DCRMs lack antibacterial activity. This research aimed to analyze the in vitro antibacterial activity of a series of copolymers consisting of a urethane–dimethacrylate monomer (UDMA), bisphenol A glycerolate dimethacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA) and urethane–dimethacrylate monomer with two quaternary ammonium groups and a 1,3-bis(1-isocyanate-1-methylethyl)benzene core (QAn+TMXDI, where n = 8, 10, or 12 is the number of carbon atoms in the N-alkyl substituent). QAn+TMXDI contents in copolymers were 20 and 40 wt.%. The results of the Staphylococcus aureus and Escherichia coli adhesion test demonstrated that the logCFU/mL decreased as the length of the N-alkyl chain decreased and QAn+TMXDI content increased. The copolymers of QA8+TMXDI 40 wt.%, Bis-GMA 40 wt.%, and TEGDMA 20 wt.% showed the highest antibacterial activity, with a logCFU/mL of 2.39 for S. aureus and no viable E. coli cells. Full article

The preference of potato plants for specific nitrogen (N) form changes with growth stage. Potato plants prefer nitrate N before tuber formation, while they favor ammonium N after tuber formation. However, few studies have focused on N species management in potato production. In this study, 2-year field experiments were conducted from 2020 to 2021 in Inner Mongolia, China, under drip irrigation with four N treatments: (1) CK (no N was used), (2) conventional farming practices (F) (urea was the only N source applied for potato growth), (3) nitrate N supplied before tuber formation and ammonium N with nitrification inhibitor supplied after tuber formation (N-NI), and (4) nitrate N supplied before tuber formation and frequent, low-dose ammonium N applied after tuber formation (Opt). The results demonstrated that, compared with the F, the Opt treatment facilitated potato N uptake, with a 33–40% increase in plant N accumulation, and significantly increased potato growth, which ultimately resulted in a yield increase of 12–20% and an increase of 11–22 percentage units in NUE. In addition, the Opt treatment reduced the soil N residual by ~14% after harvest. Compared with the N-NI, the Opt treatment did not result in a decrease in tuber yield or NUE. Therefore, supplying nitrate N before tuber formation and frequent, low-dose ammonium N after tuber formation can result in a better match between the supply and demand of potato plants for N forms without the use of nitrification inhibitors, improving both potato yield and NUE, which is of substantial agronomic and environmental value. Full article