Acquired resistance to Taxol (TAX) contributes to clinical treatment failure and significantly reduces the survival rate of patients. The present study aimed to explore the effects of exosomal ...microRNA (miR)-187-5p on TAX resistance in breast cancer cells and its underlying mechanisms. Exosomes were isolated from MCF-7 and TAX-resistant MCF-7/TAX cells, and the miR-187-5p and miR-106a-3p levels of the cells and exosomes were determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Next, MCF-7 cells were treated with TAX for 48 h and either treated with exosomes or transfected with miR-187-5p mimics. Cell viability, apoptosis, migration, invasion and colony formation were determined using Cell Counting Kit-8, flow cytometry, Transwell and colony formation assays, and the expression levels of associated genes and proteins were detected by RT-qPCR and western blotting, respectively. Finally, a dual-luciferase reporter gene assay was performed to confirm the target of miR-187-5p. The results showed that miR-187-5p expression levels increased significantly in TAX-resistant MCF-7 cells and exosomes compared with normal MCF-7 cells and exosomes (P<0.05). However, miR-106a-3p was not detected in the cells or exosomes. Therefore, miR-187-5p was selected for subsequent experiments. A series of cell assays showed that TAX inhibited the viability, migration, invasion and colony formation of MCF-7 cells and promoted their apoptosis; however, these changes were reversed by resistant cell exosomes and miR-187-5p mimics. Additionally, TAX significantly upregulated ABCD2 and downregulated beta-catenin, c-Myc and cyclin D1, whereas resistant exosomes and miR-187-5p mimics reversed the TAX-induced changes in expression. Finally, ABCD2 was confirmed to directly bind with miR-187-5p. It may be concluded that TAX-resistant cell-derived exosomes delivering miR-187-5p may affect the growth of TAX-induced breast cancer cells by targeting ABCD2 and c-Myc/Wnt/beta-catenin signaling. Key words: breast cancer, Taxol, miR-187-5p/ABCD2, drug resistance, Wnt/beta-catenin
Urea is one of the most important nitrogenous organic pollutants in water, and its removal attracts attention because of a growing concern related to water eutrophication. Urea has previously been ...considered to be largely unaffected by the UV-chlorine process. However, N-chlorourea, an intermediate of urea chlorination, has been shown to absorb ultraviolet radiation, and as such its photolysis is possible. Experiments were conducted to quantify the kinetics of N-chlorourea degradation under UV254 irradiation. The results showed that about 92% of N-chlorourea was degraded under UV254 irradiation. Ammonia and nitrate were detected as the primary nitrogen containing products of the photolysis of N-chlorourea. Solution pH ranging from 3.0 to 7.5 influenced the distribution of these products but not on the degradation rate. Based on these data, a possible pathway of photodegradation of N-chlorourea under UV254 is proposed. The degradation of urea was also achieved by the photolysis of N-chlorourea during the combined pre-chlorination and UV254 process. Insights gained in this study may be useful for exploring the potential of combined pre-chlorination and UV254 process on urea removal in water treatment.
Display omitted
•N-chlorourea was found to be degraded under UV254 irradiation.•NH4+ and NO3- were identified as the main products in photolysis of N-chlorourea.•Solution pH has remarkable influence on the formation of NH4+ and NO3-.•Removal of urea was achieved by photolysis of N-chlorourea.•The organic N in urea was mainly transformed to inorganic N during this process.
Chlorinated paraffins (CPs) in poultry feed and the farm environment might bioaccumulate in poultry eggs. Unlike chickens, which are mostly raised in cages, ducks are commonly raised free range. This ...would expose ducks to CPs in the environment. However, information on the presence of CPs on duck farms is scarce. In the present study, samples of duck eggs, duck feathers, poultry feed, and soil were collected from 25 duck farms in South China. Forty-eight congener groups of short- and medium-chain CPs (SCCPs and MCCPs) were detected in the samples. Interestingly, relatively high concentrations of SCCPs and MCCPs were found in the duck feathers. The median concentrations of SCCPs and MCCPs in the duck eggs, feathers, feed and soil were: 46 and 18 ng/g wet weight, 2460 and 992 ng/g, 103 and 47 ng/g, and 24 and 10 ng/g dry weight, respectively. The dominant groups of SCCPs and MCCPs were C10Cl6–7 and C14Cl7–8, respectively. The close relationship between duck feathers and poultry feed indicated that the duck feathers might act as a bioindicator for the exposure of ducks to CPs. The margin of exposure approach was used to assess the health risk, with the results showing that the consumption of duck eggs posed a low risk to different age groups from exposure to SCCPs and MCCPs.
Display omitted
•Higher concentrations of CPs were found in duck feathers than eggs, feed and soil.•The dominant CPs had short carbon chains and low levels of chlorine.•There was a close relationship between CPs in the feathers and feed.•The human exposure risk to CPs through duck egg consumption was low.
Polychlorinated naphthalenes (PCNs) were added to the Stockholm Convention list of persistent organic pollutants in 2015. PCNs are mainly unintentionally produced during industrial processes ...nowadays, and can be widely found in environmental media and foodstuffs. Dietary intake is the primary pathway for human exposure to PCNs. PCNs in different categories of foodstuffs have been reported. However, little information on PCN concentrations in green tea, a popular beverage worldwide is available. In this study, all 75 PCN congener concentrations and distributions in green tea samples (n = 102) from 11 regions in China were determined, and risk assessment of human exposure to PCNs through tea consumption was conducted. The PCN concentrations in all the green tea samples were 3.62–175 pg/g dry weight (mean 36.1 pg/g dry weight). Similar PCN homolog and congener profiles were found in green tea samples from different areas. The dominant PCN homologs in all of the green tea samples were di-CNs, tetra-CNs, and tri-CNs. No direct relationships were found between PCN emission sources and PCN concentrations in the green tea samples. The brewing technique could affect the PCN concentrations and homolog profiles in tea leaves. PCNs in green tea from China were found to pose little risk to humans.
Display omitted
•Different PCN concentrations were found in tea from 11 different regions.•Di-CNs, tetra-CNs, and tri-CNs were dominated homologs of PCNs.•Tea brewing technique increased the PCN concentration determined in the tea.•It posed low risk for human exposure to PCNs through green tea consumption.
Display omitted
•A fluorescent probe based on salicylate modified layered double hydroxide (LDH-SA) was prepared to establish a novel fluorescent “off–on-off” sensor.•The sensor was used for rapid ...sequential detection of Al3+ and glyphosate—1 min for Al3+ and 4 min for glyphosate respectively.•The detection process could be conducted in aqueous media without any additional organic solvents.•The Al3+ could be determined with a linear range of 0.5–10.0 μmol/L and an LOD of 0.03 μmol/L, while the linear range of glyphosate was 0.05–4.00 mg/L with an LOD of 0.03 mg/L.
A fluorescent probe based on salicylate modified layered double hydroxide (LDH-SA) is presented, enabling the swift sequential detection of Al3+, fosetyl-Al and glyphosate in aqueous environment. The probe was synthesized using a simple co-precipitation procedure, and its properties and synthesis conditions were thoroughly characterized and optimized. A unique “off-on-off” fluorescent response was observed when the probe sequentially interacted with Al3+ and glyphosate, and the detection method based on this phenomenon was established. The limits of detection for Al3+ and glyphosate were determined as 0.03 μmol/L and 0.03 mg/L, respectively, with rapid detection periods of one minute and four minutes. The LDH-SA/Al3+ complex requires Al3+ to generate a chelation-gathered fluorescence effect, which is the mechanism by which it quenches LDH-SA. This is possible due to the inhibition of excited-state intramolecular proton transfer and photoinduced electron transfer processes within LDH-SA after incorporating Al3+. Upon interaction with glyphosate, competitive complexation between glyphosate and Al3+ is initiated, which leads to a recovery of the fluorescence spectrum of LDH-SA and demonstrating the “off-on-off” behavior. An “INHIBIT” logic gate system was devised utilizing the response, indicating potential applications in fluorescence-based devices. Such a rapid, sequential detection capacity is impressive. It attests to the utility of LDH-SA as a probe for Al3+ or glyphosate, and suggests promise for applications in pollutant analysis or environmental monitoring applications.
Chlorinated paraffins (CPs) are industrial chemicals that have potential adverse effects in the environment and on human health. This study investigated CPs in apiary environment, honeybees, and bee ...products from two rural areas of Beijing, China. The median concentrations of short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) were 22 and 1.6 ng/m3 in the ambient air, 1350 and 708 ng/g dry mass (dw) in bees, 1050 and 427 ng/g dw in flowers, 37 and 54 ng/g in honey, 78 and 53 ng/g dw in bee pollen, 36 and 30 ng/g dw in soil, and 293 and 319 ng/g dw in bee wax. C10Cl6–7 and C14Cl7–8 dominated SCCPs and MCCPs in these samples, respectively. The concentrations and distributions of CPs in samples from apiaries located in the two regions varied. Long-range transportation of air masses was identified as an important source of CPs in apiaries. A close relationship between CPs in bees and the apiary environment indicated that bees could act as bioindicators for CP contamination in the environment. A human health risk assessment found that there were low risks for adults and children exposed to CPs through consumption of honey and pollen from the studied regions.
Display omitted
•CPs were ubiquitous in apiary environment, bees, and bee products.•C10Cl6–7 and C14Cl7–8 were the dominant short- and medium-chain CPs, respectively.•CP concentrations in air were distance-dependent from the city center.•CPs in bees were closely related to those in the apiary environment.•Human dietary risks of CPs were low through honey and pollen consumption.
Display omitted
•Polydopamine modified layered double hydroxides (PDA/LDH) were prepared to establish a novel fluorescent “turn-off” sensor.•The sensor was used for rapid detection of thiram via the ...internal filter effect (IFE).•The detection process could be performed instantly after the addition of thiram.•The linear range of thiram was found to be 50–50000 μg L−1 (R2 = 0.9976), and the limit of detection was 25 μg L−1.•The prepared probes were successfully applied in apple and pear samples, with recovery rates of 92.06–104.90%.
A low-cost and environmentally friendly polydopamine modified layered double hydroxides (PDA/LDH) was prepared, and a novel fluorescent “turn-off” sensor was established for rapid detection of thiram. The material was characterized using the transmission electron microscope (TEM), Fourier transform-infrared (FT-IR), X-ray diffraction (XRD), X-ray photo-electronic spectroscopy (XPS) and other methods. The electrostatic interaction, hydrogen bonding and S-π interaction between PDA/LDH and thiram were mostly attributed to the sensing of thiram. Through the internal filter effect (IFE), the fluorescence of the PDA/LDH could be effectively quenched by thiram. The limit of detection (LOD) was determined to be 25 μg L−1 under optimal conditions, while the concentration of thiram in the range of 50–50000 μg L−1 exhibited a satisfactory relationship with the change in fluorescence intensity. Furthermore, the prepared probes were successfully applied on apple and pear samples, in which the recovery rate could reach 92.06–104.90 %. The synthesis of PDA/LDH was quite simple, and the detection of thiram could be accomplished right away when the sensor and thiram were combined. All the above results demonstrated the high potential of the established method in practical applications.
•Increased efficiency of catalytic conversion of cellulose to ketols.•Enhanced selectivity of hydroxyacetone and 1-hydroxy-2-butanol.•Modification of nickel complex carbide catalysts optimizes ...electron transfer to enhance activity to greatest extent.
The metal immobilizing micro-circumstance is intensively relevant to its catalytic activity and selectivity. In order to obtain C3,4 ketols by protection of C = O bonds against further hydrogenation, we proposed a promising strategy to modify adjacent circumstance for nickel complexes carbide catalysts (CCCs). The Sn promoted nickel CCCs exhibited high selectivity for cellulose conversion to C3,4 ketols with the yield of 54.8%. The characterization results demonstrated the coordination environment of metals were reconstructed by CxNy species to form isolated nickel sites. The size-dependent electron transfer occurred when the sizes changed (from cluster to nanoparticles). This electron transfer facilitated promotion of the selectivity for C3,4 ketols by protection of CO bonds against further hydrogenation. Combined with density functional theory calculations, the size-dependent electron transfer and Lewis base forming mechanism in Ni@CxNy structure were revealed. CxNy phases changed the electronic abundance of Ni sites and subsequently acted as Lewis base. Our work hinted that size of metallic catalysts should be optimized in specific loading circumstance to maximize the catalytic selectivity rather than simply chasing atomic efficiency.
The traditional sustainable livelihood framework assumes that livelihood capital has a “complementary” effect, and that combining capitals improves the adaptability of farmers. However, this ...framework disregards the possibility that the “substitution” effect in the conversion of livelihood capital increases the vulnerability of farmers' livelihoods. The difference between the two lies in whether livelihood capitals are mutually exclusive or mutually reinforcing, which can result in an increased adaptive capacity for farmers. In this study, structural equation modeling and fuzzy set qualitative comparison analysis were combined. Coastal villages in Shankou Town, Guangxi, China, were analyzed in a case study to identify the incentive and restrictive livelihood capitals affecting the improvement of farmers' adaptive capacity. Moreover, the “complementary” and “substitution” effects of incentive and restrictive livelihood capitals were explored. The results indicate the existence of a “complementary” effect among incentive livelihood capitals (i.e., material, social, human, and natural capitals), which improves farmers' adaptability. Moreover, material and social capital exert a strong “complementary” effect on other capitals. Psychological and financial capital, as limiting livelihood capitals that obstruct the improvement of farmers’ adaptability, can replace both human and natural capital. When providing livelihood compensation for farmers in vulnerable areas, material and social capital with a strong “complementary” effect compensation should be prioritized, while capital with a “substitution” effect should only be compensated selectively. The priorities for policymakers are also determined to ensure both livelihood compensation and the optimal allocation of limited funds. Moreover, a reference is provided to improve the adaptive capacity of farmers in vulnerable areas.
•There are not only complementary effects but also substitution effects among livelihood capitals.•Substitution capitals are mutually exclusive, increasing the likelihood of vulnerable livelihoods.•The substitution effect is the key in prioritizing livelihood compensation.•The addition of complementary capital portfolios improves farmers' adaptability.•Complementary capital should be compensated first.
The capability approach has long been confined to a static, short-term framework, preventing it from truly providing normative guidance for enhancing multidimensional well-being and sustainable ...development. Human well-being cannot be seen as fixed, so there is an urgent need to assess the capability approach from a dynamic and long-term perspective. In this paper, the Beibu Gulf Mangrove National Natural Reserve of China was selected as a study area. A sustainable development perspective was integrated into a static capability approach theory framework, focusing on changes in capability approach with a dynamic, long-term gaze, and the impact of coastal zone ecological protection policies on farmers' multidimensional well-being was measured at spatial and temporal scales. The results indicate that ecological conservation policies reduce the level of capability approach of farm households in the short term. However, from a dynamic and long-term perspective, once the “pain period” is over, the capability approach can be continuously improved, achieving a win-win situation for both farmer well-being and ecological sustainability. This result also innovatively verified the core of the capability approach, which states that “freedom” under the capability approach framework is not unrestricted freedom, but restricted freedom. This will further expand and improve the relevant research of Sen's capability approach theory, and is also a beneficial exploration of combining Sen's capability approach theory with the Sustainable Development Goals. In order to solve the contradiction between peasant household welfare development and environmental protection, we need to explore a new scheme. The results of the study provide the government and policy makers with ideas for improving ecological protection policies, along with a more accurate and scientific basis for optimizing the multidimensional welfare compensation system to improve the feasibility and effectiveness of policy implementation.
•The capability approach cannot be confined to a static framework.•It takes a long time for ecological protection policies to improve human well-being.•True “freedom” is restricted and constrained.•Appropriate policy interventions can promote sustainable development.
