217 research outputs found

    Evidence of partial thermal compensation in natural phytoplankton assemblages

    Get PDF
    Whether phytoplankton growth is solely constrained by temperature (hotter is better) or compensated by thermal adaptation is still under debate. We measured the temperature sensitivity of natural phytoplankton communities at both short‐term and seasonal timescales using temperature manipulation experiments. The activation energy across communities (mean ± SE: E i = 0.51 ± 0.12 eV, Q10 = 1.98) is significantly lower than that within communities (E a = 0.80 ± 0.10 eV, Q10 = 2.80). Moreover, using a larger dataset of phytoplankton growth rates measured in (sub)tropical waters, we estimated the across‐community activation energy as 0.33 ± 0.06 eV (Q10 = 1.56), which is also lower than E a . Our study is the first to suggest the “hotter is partially better” for natural phytoplankton communities, indicating that the phytoplankton communities can show some thermal adaptation capability. Our results highlight the importance of incorporating the differential temperature sensitivities at different timescales into the biogeochemical models to better evaluate how marine ecosystems will respond to climate changes

    Photocatalytic Degradation of Dimethoate in Bok Choy Using Cerium-Doped Nano Titanium Dioxide

    Get PDF
    Dimethoate, a systemic insecticide, has been used extensively in vegetable production. Insecticide residues in treated vegetables, however, pose a potential risk to consumers. Photocatalytic degradation is a new alternative to managing pesticide residues. In this study, the degradation of dimethoate in Bok choy was investigated under the field conditions using cerium-doped nano titanium dioxide (TiO2/Ce) hydrosol as a photocatalyst. The results show that TiO2/Ce hydrosol can accelerate the degradation of dimethoate in Bok choy. Specifically, the application of TiO2/Ce hydrosol significantly increased the reactive oxygen species (ROS) contents in the treated Bok choy, which speeds up the degradation of dimethoate. Ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS) analysis detected three major degradation products, including omethoate, O,O,S-trimethyl thiophosphorothioate, and 1,2-Bis (acetyl-N-methyl-) methane disulfide. Two potential photodegradation pathways have been proposed based on the intermediate products. To understand the relationship between photodegradation and the molecular structure of target insecticides, we investigated the bond length, Mulliken atomic charge and frontier electron density of dimethoate using ab initio quantum analysis. These results suggest the P = S, P-S and S-C of dimethoate are the initiation sites for the photocatalytic reaction in Bok choy, which is consistent with our empirical data

    Response behavior of antibiotic resistance genes and human pathogens to slope gradient and position: an environmental risk analysis in sloping cultivated land

    Get PDF
    Soils, especially in farmlands, are key media for the transmission of antibiotic resistance genes (ARGs) and their hosts from the environment to humans. Sloping farmland is an important agricultural resource, but there lack of studies on the fate and risk of ARGs in sloping land. Also, the behavior and drivers of ARGs in response to slope gradient and position are unclear. Here, metagenomics was used to investigate the profiles of ARGs, mobile genetic elements, and microbial communities in soils from lands of five slope gradients (5°, 10°, 15°, 20°, and 25°) with two slope positions (uphill and downhill). Results showed that while the abundance (except 15°) and diversity (except 20°) of ARGs increased as the slope gradient increased, the diversity of ARGs with health risk, especially the high-risk ones, decreased. For slope positions, abundant and diverse ARGs were more likely to accumulate at downhill. Furthermore, 52 bacterial genera and 12 human pathogenic bacteria (HPB) species were identified as the potential hosts for ARGs with high risk, and abundant HPB species were also detected in the soils with low gradients at downhill. Moreover, the structural equation model analysis revealed that the slope gradient and the slope position have both direct and indirect effects on the abundance of ARGs. Further correlation analysis revealed that the slope gradient has a positive effect (p < 0.05) on nitrite nitrogen in the soils. Also, the slope position has a negative effect (p < 0.05) on total phosphorus and microbial nitrogen, while positively affected (p < 0.05) on particulate nitrogen and microbial carbon, which were the key factors driving the behavior of ARGs. Overall, this study provided comprehensive information on ARGs with health risks and their potential pathogenic hosts in sloping farmland. It can be important for controlling antibiotic resistance transmission and be consistent with the One Health framework

    Photocatalytic Degradation of Profenofos and Triazophos Residues in the Chinese Cabbage, \u3cem\u3eBrassica chinensis\u3c/em\u3e, Using Ce-Doped TiO\u3csub\u3e2\u3c/sub\u3e

    Get PDF
    Pesticides have revolutionized the modern day of agriculture and substantially reduced crop losses. Synthetic pesticides pose a potential risk to the ecosystem and to the non-target organisms due to their persistency and bioaccumulation in the environment. In recent years, a light-mediated advanced oxidation processes (AOPs) has been adopted to resolve pesticide residue issues in the field. Among the current available semiconductors, titanium dioxide (TiO2) is one of the most promising photocatalysts. In this study, we investigated the photocatalytic degradation of profenofos and triazophos residues in Chinese cabbage, Brassica chinensis, using a Cerium-doped nano semiconductor TiO2 (TiO2/Ce) under the field conditions. The results showed that the degradation efficiency of these organophosphate pesticides in B. chinensis was significantly enhanced in the presence of TiO2/Ce. Specifically, the reactive oxygen species (ROS) contents were significantly increased in B. chinensis with TiO2/Ce treatment, accelerating the degradation of profenofos and triazophos. Ultra-performance liquid chromatography–mass spectroscopy (UPLC-MS) analysis detected 4-bromo-2-chlorophenol and 1-phenyl-3-hydroxy-1,2,4-triazole, the major photodegradation byproducts of profenofos and triazophos, respectively. To better understand the relationship between photodegradation and the molecular structure of these organophosphate pesticides, we investigated the spatial configuration, the bond length and Mulliken atomic charge using quantum chemistry. Ab initio analysis suggests that the bonds connected by P atom of profenofos/triazophos are the initiation cleavage site for photocatalytic degradation in B. chinensis

    A Network Pharmacology Approach to Explore the Pharmacological Mechanism of Xiaoyao Powder on Anovulatory Infertility

    Get PDF
    Aim. To explore the pharmacological mechanism of Xiaoyao powder (XYP) on anovulatory infertility by a network pharmacology approach. Method. Collect XYP’s active compounds by traditional Chinese medicine (TCM) databases, and input them into PharmMapper to get their targets. Then note these targets by Kyoto Encyclopedia of Genes and Genomes (KEGG) and filter out targets that can be noted by human signal pathway. Get the information of modern pharmacology of active compounds and recipe’s traditional effects through databases. Acquire infertility targets by Therapeutic Target Database (TTD). Collect the interactions of all the targets and other human proteins via String and INACT. Put all the targets into the Database for Annotation, Visualization, and Integrated Discovery (DAVID) to do GO enrichment analysis. Finally, draw the network by Cytoscape by the information above. Result. Six network pictures and two GO enrichment analysis pictures are visualized. Conclusion. According to this network pharmacology approach some signal pathways of XYP acting on infertility are found for the first time. Some biological processes can also be identified as XYP’s effects on anovulatory infertility. We believe that evaluating the efficacy of TCM recipes and uncovering the pharmacological mechanism on a systematic level will be a significant method for future studies

    The fate of frozen human embryos when transferred either on the day ofthawing or after overnight culture

    Get PDF
    Objective: To study the performance of thawed zygotes and cleavage stage embryos transferred either on the day of thaw or after overnight culture. Methods: A retrospective study of 864 frozen embryo transfer cycles. Cryosurvival rates per thawed embryo and implantation rates were analysed for embryos frozen on Day 1, Day 2 or Day 3 relative to oocyte collection (Day 0) and transferred on the day of thaw or after overnight culture, together with clinical pregnancy rates and prevalence of multiple gestations. Results: Survival of Day 3 embryos was significantly lower than those frozen on Day 1 (P=0.017) or Day 2 (P=0.015). Following overnight culture, resumption of mitosis of zygotes was more frequent than Day 2 (P=0.000) which are in turn higher than Day 3 (P=0.000) embryos. The implantation rate for Day 2 embryos dividing overnight was significantly higher than those that did not divide for women (P=0.001) but not those women (P=0.055). There were no differences in the implantation rates for those dividing or not after culture, for embryos frozen on Day 3 for women (P=0.254) or (P=0.403). Conclusions: Later cleavage stage post-thaw embryos survive and resume mitosis less frequently compared to earlier stages. Embryos not resuming mitosis after culture overnight can implant, particularly Day 3 embryos, suggesting that they can further increase the cumulative pregnancy rate per oocyte collection and that discarding them is wasteful. Overnight culture is best used for logistical reasons rather than a strategy to improve pregnancy rates

    Preoperative ultrasound identification and localization of the inferior parathyroid glands in thyroid surgery

    Get PDF
    IntroductionThe parathyroid glands are important endocrine glands for maintaining calcium and phosphorus metabolism, and they are vulnerable to accidental injuries during thyroid cancer surgery. The aim of this retrospective study was to investigate the application of high-frequency ultrasound imaging for preoperative anatomical localization of the parathyroid glands in patients with thyroid cancer and to analyze the protective effect of this technique on the parathyroid glands and its effect on reducing postoperative complications.Materials and methodsA total of 165 patients who were operated for thyroid cancer in our hospital were included. The patients were assigned into two groups according to the time period of surgery: Control group, May 2018 to February 2021 (before the application of ultrasound localization of parathyroid in our hospital); PUS group, March 2021 to May 2022. In PUS group, preoperative ultrasound was used to determine the size and location of bilateral inferior parathyroid glands to help surgeons identify and protect the parathyroid glands during operation. We compared the preoperative ultrasound results with the intraoperative observations. Preoperative and first day postoperative serum calcium and PTH were measured in both groups.ResultsOur preoperative parathyroid ultrasound identification technique has more than 90% accuracy (true positive rate) to confirm the location of parathyroid gland compared to intraoperative observations. Postoperative biochemical results showed a better Ca2+ [2.12(0.17) vs. 2.05(0.31), P=0.03] and PTH [27.48(14.88) vs. 23.27(16.58), P=0.005] levels at first day post-operation in PUS group compared to control group. We also found a reduced risk of at least one type of hypoparathyroidism after surgery in control group:26 cases (31.0%) vs. 41 cases (50.6%), p=0.016.ConclusionUltrasound localization of the parathyroid glands can help in the localization, identification and in situ preservation of the parathyroid glands during thyroidectomy. It can effectively reduce the risk of hypoparathyroidism after thyroid surgery

    Marine phytoplankton in subtropical coastal waters showing lower thermal sensitivity than microzooplankton

    Get PDF
    Temperature sensitivity of plankton in terms of activation energy (Ea, eV) in the Arrhenius equation is critical for predicting how marine productivity and carbon export will respond to ocean warming. In this study, we quantified the temperature responses of phytoplankton growth rate and microzooplankton grazing rate by conducting short-term temperature modulation experiments on natural communities at two subtropical sites with contrasting nutrient conditions. Our results showed that the activation energy of phytoplankton growth rate (Ea = 0.36 eV, 95% confidence interval [CI] = 0.28–0.44 eV) at each station was less than that of microzooplankton grazing rate (Ea = 0.53 eV, 95% CI = 0.47–0.59 eV), indicating an increasing grazing pressure on phytoplankton under warming conditions. Although the difference is consistent with that reported in previous studies, it is very likely to arise from another reason, i.e., differential proximities of the optimal temperature (Topt in nonlinear temperature responses of rates) of phytoplankton and microzooplankton to the environmental temperature, as we found that the environmental temperature is closer to the optimal temperature of phytoplankton growth than to that of microzooplankton grazing in this subtropical environment. Our results suggest that nonlinear temperature responses of plankton should be considered when evaluating and predicting the effects of ocean warming on ecosystem productivity and food web dynamics, especially in subtropical and tropical waters
    • 

    corecore