Although predation risk exists under natural conditions, its role is usually ignored when evaluating the ecotoxicity of environmental contaminants, and the interaction between predation risk and ...antibiotic ecotoxicity is not yet clear. To investigate the nonconsumptive effects (NCEs) of predation on the ecotoxicity evaluation of antibiotics, the median lethal concentration (LC50), relative population growth rate (RGR), and activities of three antioxidases were measured in the ciliate Paramecium jenningsi exposed to graded concentrations of the antibiotics nitrofurazone (NFZ) or erythromycin (ERY) in the presence or absence of a predator, i.e., the ciliate Didinium nasutum. The results showed that (1) NCEs significantly reduced the LC50 of NFZ but had no effect on that of ERY; (2) predation pressure alone had no significant effect on the inhibitory rate of the P. jenningsi population, but the interaction with NFZ was synergistic, while that with CRY was additive; (3) the concentrationresponse (i.e., mortality) model for each antibiotic exposure with and without predation pressure differed significantly in the parameter slope; (4) RGRs were significantly reduced by antibiotic exposure or NCEs; only in NFZ-exposed groups did the RGRs decrease linearly with increasing exposure concentration; and (5) the activities of all three antioxidases significantly increased due to NCEs or following exposure to antibiotics. In brief, NCEs were detected in P. jenningsi, and these had additive or synergistic effects on antibiotic ecotoxicity, but their magnitude depended on the properties and exposure concentrations of the antibiotics. Our findings suggest that it is necessary to consider the roles of NCEs in the ecotoxicity evaluation of environmental contaminants.
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•NCEs were detected in the ciliated protozoa Didinium-Paramecium.•The ecotoxicity of nitrofurazone (NFZ) and erythromycin (ERY) was investigated in Paramecium jenningsi.•NCEs affected the ecotoxicity evaluation of NFZ and ERY.•Antibiotic ecotoxicity demonstrated interaction with NCEs.•The magnitude of NCEs depends on antibiotic properties and exposure method.
There is a growing need in the marketing field to understand how consumers can be persuaded to consume healthier products. This research makes novel predictions about the time-of-day effects on ...(un)healthy product purchases based on self-control theory. We investigated whether and how time of day (morning vs. evening) influences consumers’ (un)healthy product purchases. A field study based on point-of-sales data indicated that consumers tend to buy more unhealthy products in the evening. Two laboratory experiments confirmed that this is due to a decrease in self-control in the evening, which leads consumers to purchase more unhealthy products at this time. A follow-up eye-tracking experiment further revealed potential mechanisms whereby lower self-control causes consumers to focus more on unhealthy products and weakens the effect of attention to healthy products on purchases. The findings provide valuable insights into consumer behavior and marketing decisions for marketing academics, retailers and consumer marketing companies.
Decades of reckless deforestation have caused serious soil erosion and land desertification issues in the Loess Plateau (LP). “Grain for Green” Program (GFGP), one of the world’s largest ecological ...restoration projects, is crucial to improve the ecological environment. Previous studies have demonstrated that GFGP lowers soil erosion in the LP. However, there are trade-offs and synergies between ecological services. Does strengthening soil conservation prevent enhancing other ecosystem services? Consequently, can the GFGP improve many ecological services simultaneously? This study compares changes in NDVI prior to and following the implementation of the GFGP in LP to the enhancement of ecosystem services. During the research period, the LP’s overall vegetation cover rose significantly, particularly in the GFGP’s major counties. Significant improvements were made to ecosystem services such as carbon sequestration, soil conservation, and habitat quality. The GFGP enhanced the synergistic linkages between ecological services. The implementation of the GFGP decreased water yield, suggesting trade-offs with other ecosystem services. Additionally, we investigate regional trade-offs/synergies between ecosystem services and their influencing factors, which were influenced by topographic and climatic variables. To maximize the benefits of ecological restoration efforts, we need a deeper understanding of the relationships between ecosystem services and the mechanisms that drive them. Thus, policymakers can scientifically exert control over local influences on ecosystem services, either by boosting the provision of specific services or by limiting specific influences in order to maintain ecosystem stability.
Gold nanoparticles (AuNPs)-based lateral flow immunoassay (LFIA) is a widely used detection technique. Here, we developed a novel method for green synthesis of a salt-tolerant AuNPs by using aqueous ...extract of Damask rose petals (AEDR), for the application of
Listeria monocytogenes
(
L. monocytogenes
) detection by LFIA. Key parameters were optimized to achieve an improved optical LFIA performance, and the detection limit and specificity were further studied. AEDR-AuNPs were synthesized within 1 min at RT by AEDR at a concentration of 240 µg/mL, and the method was rapid, simple, economical and environmentally friendly. The AEDR-AuNPs were spherical with the size mainly ranging from 20 to 28 nm, and the salt stability was determined to be 0.4 M NaCl, which is 10 times higher than AuNPs synthesized by citrate reducing method. The optimized immunization concentration of anti-
Listeria monocytogenes
polyclonal antibody to AEDR-AuNPs was 60 µg/mL. The optimized antibody concentrations of test (
T
) line and control (
C
) line were determined as 1 mg/mL and 0.5 mg/mL, respectively. The detection limit was 2.5 × 10
5
CFU/mL and 2.85 × 10
5
CFU/mL in pure
L. monocytogenes
culture and pork tenderloin sample, respectively, and the result can be read by naked eye within 10 min. The antibody–AEDR-AuNPs LFIA strip showed no cross-reaction with all the tested bacteria including
Staphylococcus aureus, Pseudomonas aeruginosa, Vibrio parahaemolyticus, Bacillus subtilis, Escherichia coli
O157:H7 and
Salmonella typhimurium
. This approach showed a promising application for the detection of
L. monocytogenes
concerning food safety.
Materials under high pressure usually exhibit unique chemical and physical properties. Polynitrogen compounds have received widespread attention as potential high energy density materials. This paper ...uses CALYPSO crystal structure prediction method to study the structures of ScN6 and ScN7 in 0–100 GPa. Theoretical calculations show that ScN6 is thermodynamically stable above 80 GPa, while ScN7 is thermodynamically stable from 30 GPa to 90 GPa. Furthermore, ScN7 is metastable under ambient conditions, demonstrating that it can be quenched to ambient conditions after high pressure synthesis. The P1¯-ScN6 is a three-dimensional extended fold multi-nitrogen network, and the P1¯-ScN7 contains a five-membered ring and a curved N4 molecular unit. Both P1¯-ScN6 and P1¯-ScN7 contain a lot of N–N single bonds and N=N double bonds. The energy densities of P1¯-ScN6 and P1¯-ScN7 are 3.97 kJ g−1 and 3.12 kJ g−1, respectively. The detonation velocity and detonation pressure of the P1¯-ScN6 phase and P1¯-ScN7 phase are also higher than that of TNT. Excellent energy storage properties and detonation performance show that they can be used as potential high-energy materials. These results opened up a new way for the synthesis of nitrogen-rich compounds.
Land degradation directly affects global and regional economic, social development, and food security, which has become a hot and challenging issue in the global ecological field. A successful ...response to land degradation requires understanding its causes, impacts, and extent. It is also essential to recognize the effects of climate, soil, water, land cover, and socioeconomic factors on land degradation. Therefore, assessing land degradation risk can help prevent and reverse land degradation trends, especially for the main grain production area. The Environmental Sensitivity Area Index (ESAI) was used to identify land degradation sensitive areas in the North China Plain and combined with a random forest model to determine the main drivers affecting land degradation and predict future land degradation sensitive areas. The results show decreasing land degradation risk in the North China Plain. In 2015, the sensitivity of land degradation in the North China Plain had improved. The proportion of land area with high sensitivity to land degradation reduced to 0.02%. Combining the spatial and temporal distribution of ESAI and the prediction results of the random forest model, we know that socio-economic factors have the most significant impact on land degradation sensitivity. Although the risk of land degradation is decreasing, it is still necessary to pay attention to the possible future land degradation risk to stabilize food production. Assessing land degradation risk in North China Plain provides important decision information for rational and sustainable land management and has more vital practical significance.
•The land degradation sensitivity in North China Plain improved.•The ESAI and random forest model were combined to predict the future land degradation risk trends in the North China Plain.•The growth of population and GDP are important influencing the potential risk of land degradation.
High-purity insoluble dietary fiber from okara (okara-HPIDF) is a raw material with a potentially positive effect on colon health. However, the mechanisms of the effect are far from clear. In this ...study, okara-HPIDF and low-purity dietary fiber from okara (okara-LPDF) were fed to C57BL/6 mice with acute ulcerative colitis induced by DSS. The levels of inflammatory factors, bacterial 16S rDNA sequencing, short-chain fatty acids (SCFAs), and bioinformatics were analyzed with the colonic tissue status. The results showed that the intake of HPIDF affected the proliferation of the key bacteria
,
, and
in the PWY-2941 pathway and AEROBACTINSYN-PWY pathway, and then affected the synthesis of SCFAs, providing a positive role for colon health. However, the intake of HPIDF was unable to repair colonic injury caused by DSS-induced acute ulcerative colitis mainly owing to the abundance of
in the colon. This study demonstrates that the recommended intake content of HPIDF can ameliorate colonic environment disturbance caused by acute ulcerative colitis, but not enough to relieve it.
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•The P21/c-BaN3, P1¯-BaN4 and P1¯-BaN5 are energetically favorable under different pressures.•All three high-pressure structures contain six-membered rings consisting of NN single ...bond and NN double bond.•The P21/c-BaN3 was dynamically stable at ambient pressure, and it may be quenchable at ambient pressure after synthesis at high pressure.•The energy densities of P1¯4 and P1¯5 are comparable to that of TATB, RDX, and the detonation velocity and detonation pressure of the two structures are second only to TNT.
Alkaline-earth metal nitrides have attracted widespread attention due to their promising potential for high energy–density materials. We predicted the new structures of N-rich BaNx (x = 3–5) compounds under high pressure and analyze their potential properties in this paper. The P21/c-BaN3 was discovered for the first time and it can exist stably when the pressure exceeds 100 GPa. Besides, both the new structures of P1¯-BaN4 and P1¯-BaN5 have lower energy values than the previously predicted structures at pressures of 90 GPa and 70 GPa, respectively. The three novel N-rich barium–nitrogen compounds are dynamically stable under high pressure conditions. Especially, it was found that the phase of P21/c-BaN3 can maintain dynamic stability at ambient condition by the AIMD. So, the P21/c-BaN3 is a metastable structure and it is not only synthesized at high pressure, but also can be quenched to ambient conditions. Moreover, the energy densities of P1¯-BaN4 and P1¯-BaN5 are equivalent to that of TATB, RDX, and the detonation velocity and detonation pressure of the two structures are second only to TNT. This paper provides important help for the research of N-rich alkaline earth metal Ba–N Compounds.
In recent years, 3D hydrogels based on alginate (Alg) have undergone substantial advancements, holding transformative potential for biomedicine and regenerative medicine. Nevertheless, the viscosity ...of Alg needs to be further increased, in order to print complex 3D structures. Attempts to adjust printability often employ rheological modifiers like methylcellulose (MC), but these still lack mechanical integrity for broader biomedical applications. Our study sought to chemically modify Alg/MC to create a photopolymerizable hydrogel by incorporating acrylate-based monomers, which would enhance the curing ability of the base hydrogel, leading to better mechanical properties of Alg/MC, such as stretchability and stability with shape recovery. Comprehensive mechanical assessments unveiled remarkable tensile properties, achieving a notable specific strength benchmark of 44.72 kPa/(g.cm-3) before reaching the point of fracture. This represents a substantial 250 % improvement compared to samples lacking the acrylate monomer. Biomedical assessments confirmed the hydrogel's promising potential, especially with the MG-63 cell line, underscoring its suitability for advanced applications like tissue engineering.
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Ecotoxic effects of antibiotics or ammonium have been confirmed independently in aquatic animals, but few studies have investigated their combined effects. In aquaculture ecosystems, these pollutants ...frequently coexist, and often in high concentrations. In this study, the combined effects of antibiotic nitrofurazone and NH4Cl on the population dynamics and growth rates of two species of ciliated protists,
Euplotes vannus
and
Pseudokeronopsis rubra
, were investigated. Profiles of the dose-responses were visualized, and interactions between the two pollutants were quantified by the response surface method (RSM). Results showed that 1) the dynamics of the population growth differed significantly between the testd ciliates and varied with the concentrations of the pollutants; 2) the relative growth rate (RGR) of both ciliates decreased significantly with increased pollutant concentrations, while the difference in RGR between the two ciliates was not significant; 3) RSM analysis demonstrated an additive effect of nitrofurazone and NH4Cl on the RGR in both ciliates. In brief, ecotoxic effects can be caused by nitrofurazone and ammonium independently on the two test ciliates, and such effects can be strengthened when they present at the same time. These findings offer a valuable reference for evaluating combined ecotoxic effects caused by multiple pollutants in aquaculture ecosystems.
