36 research outputs found

    New insights into the cortex-to-stele ratio show it to effectively indicate inter- and intraspecific function in the absorptive roots of temperate trees

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    The cortex-to-stele ratio (CSR), as it increases from thin- to thick-root species in angiosperms, is theorised to effectively reflect a compensation for the ‘lag’ of absorption behind transportation. But it is still not known if this compensatory effect exists in gymnosperm species or governs root structure and function within species. Here, anatomical, morphological, and tissue chemical traits of absorptive roots were measured in three temperate angiosperm and three gymnosperm species. Differences in the CSR and the above functional traits, as well as their intraspecific associations, were analyzed and then compared between angiosperms and gymnosperms. At the intraspecific level, the CSR decreased with increasing root order for all species. The expected functional indication of the CSR was consistent with decreases in specific root length (SRL) and N concentration and increases in the C to N ratio (C:N ratio) and the number of and total cross-sectional area of conduits with increasing root order, demonstrating that the CSR indicates the strength of absorption and transportation at the intraspecific level, but intraspecific changes are due to root development rather than the compensatory effect. These trends resulted in significant intraspecific associations between the CSR and SRL (R2 = 0.36 ~ 0.80), N concentration (R2 = 0.48 ~ 0.93), the C:N ratio (R2 = 0.47 ~ 0.91), and the number of (R2 = 0.21 ~ 0.78) and total cross-sectional area (R2 = 0.29 ~ 0.72) of conduits in each species (p< 0.05). The overall mean CSR of absorptive roots in angiosperms was four times greater than in gymnosperms, and in angiosperms, the CSR was significantly higher in thick- than in thin-rooted species, whereas in gymnosperms, the interspecific differences were not significant (p > 0.05). This suggests that the compensation for the lag of absorption via cortex thickness regulation was stronger in three angiosperm species than in three gymnosperm species. In addition, there was poor concordance between angiosperms and gymnosperms in the relationships between CSRs and anatomical, morphological, and tissue chemical traits. However, these gymnosperm species show a more stable intraspecific functional association compared to three angiosperm species. In general, absorptive root CSRs could manifest complex strategies in resource acquisition for trees at both intra- and interspecific levels

    The Influence of Agricultural Production Mechanization on Grain Production Capacity and Efficiency

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    As an important production factor of grain production, agricultural machinery can effectively provide a theoretical basis for agricultural modernization development strategies by exploring its impact on grain production capacity and efficiency. This research starts from the two aspects of grain production capacity and grain production efficiency, takes rice, wheat, and corn as the research objects, and uses the C–D production function and Tobit model as the basis, respectively, to establish two impact models of production capacity and production efficiency. At the same time, according to the different emphases of the two models, this research designs different variable systems and finally uses the data from 2017 to 2021 for empirical analysis. The research results show that the influence coefficients of machinery service income and machinery power resource input on the total grain production capacity are 0.0976 and 0.0437, respectively, with a significant positive impact. At the same time, for rice crops, wheat crops, and corn crops, the amount of mechanization cost per mu has a significant positive impact on the yield capacity of crops, with impact coefficients of 0.0311, 0.0827, and 0.0233, respectively. The supply level of agricultural machinery services and the utilization rate of agricultural machinery services per mu have a significant positive impact on grain production efficiency. The impact coefficients of the supply level of agricultural machinery services per mu are 0.0192, 0.0587, and 0.0241, respectively. The impact coefficients of the agricultural machinery service utilization rate are 0.0059, 0.0148, and 0.0607, respectively, with a significant positive impact. It can be seen that agricultural production mechanization can effectively promote the improvement in grain production capacity and efficiency and promote the process of agricultural modernization. At present, most of the research on industrial mechanization services is biased toward the choice of agricultural mechanization services by farmers. However, this research has carried out the impact mechanism analysis from the perspective of time and space and the perspective of crops, rationalizing the impact mechanism of agricultural production capacity and agricultural production efficiency under agricultural mechanization

    Description of larva of Euphaea superba Kimmins, 1936 (Odonata: Zygoptera: Euphaeidae) from China

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    Wu, Xiangjuan, Liu, Zhen, Chen, Yu, Wang, Beixin (2019): Description of larva of Euphaea superba Kimmins, 1936 (Odonata: Zygoptera: Euphaeidae) from China. Zootaxa 4545 (4): 585-592, DOI: https://doi.org/10.11646/zootaxa.4545.4.

    Protein Kinase D was involved in vascular remodeling in spontaneously hypertensive rats

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    The present study was designed to determine the role of PKD in vascular remodeling (VR) in Spontaneously hypertensive rats (SHRs). Increased SBP, VR and PKD activation were prominent in SHRs. The SBP has a positive correlation with the activation of PKD in SHRs. The ratio of media to lumen (MT/LD), volume fraction of collagen (VFC), hydroxyproline, IL-6, TNF-α and nitrotyrosine content were significantly related to the activated PKD. It may be concluded that PKD plays a central role in VR, and the mechanism may be related to its regulation of hypertrophy, fibrosis, inflammation and oxidative stress

    Evaluation of pars plana sclera fixation of posterior chamber intraocular lens

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    Purpose: The purpose of this study was to evaluate the clinical efficacy and safety of modified posterior chamber intraocular lens (PCIOL) implantation with transscleral fixation. Design and Setting: This is a study, which is conducted at Department of Ophthalmology, Jinan Eye Hospital, Jinan Second People′s Hospital. Materials and Methods: A total of 82 patients who were scheduled for sutured PCIOL were divided randomly into modified and conventional groups. The former underwent PCIOL through pars plana fixation with knot buried and without scleral flap and the latter underwent transscleral fixation of PCIOL in the ciliary sulcus. The main outcome measures included operative time, postoperative visual acuity, and postoperative complications. Results: The mean operative time of the modified group was 39.95 ± 5.87 min, which was significantly less than that of the conventional group (45.77 ± 5.21 min; P < 0.05). No difference was found in postoperative visual acuity between the two groups. There were no significant postoperative complications, including knot exposure, endophthalmitis, and retinal detachment in either group. The optical clamping of PCIOL was prone to occur in the conventional group. Conclusion: Modified sutured PCIOL implantation is a safe, effective, and feasible technique for the correction of aphakia in eyes without adequate posterior capsular support

    Additional file 1: Tables S1. of Capability of leaf interdigitation with different inverse planning strategies in Monaco: an investigation of representative tumour sites

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    The PTV comparative results of the leaf interdigitation plans and leaf non-interdigitation plans in NPC sites. Tables S2. The PTV comparative results of the leaf interdigitation plans and leaf non-interdigitation plans in cervical sites. Tables S3. The PTV comparative results of the leaf interdigitation plans and leaf non-interdigitation plans in prostate sites. Tables S4. The OARs parameter values of the leaf interdigitation plans and leaf non-interdigitation plans in NPC sites. Tables S5. The OARs parameter values of the leaf interdigitation plans and leaf non-interdigitation plans in cervical sites. Tables S6. The OARs parameter values of the leaf interdigitation plans and leaf non-interdigitation plans in prostate sites. Table S7. Delivery efficiency of the leaf interdigitation plans and leaf non-interdigitation plans in NPC sites. Table S8. Delivery efficiency of the leaf interdigitation plans and leaf non-interdigitation plans in cervical sites. Table S9. Delivery efficiency of the leaf interdigitation plans and leaf non-interdigitation plans in prostate sites. (DOCX 23 kb

    Insights into the Kinetics, Theoretical Model and Mechanism of Free Radical Synergistic Degradation of Micropollutants in UV/Peroxydisulfate Process

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    The degradation of acyclovir (ACY) and atenolol (ATL) in the UV/peroxydisulfate (UV/PDS) process has been systematically considered, focusing on the degradation kinetics, theoretical models, and reaction pathways via applying a microfluidic UV reaction system. The removal efficiencies of ACY and ATL were &gt;94.8%, and the apparent degradation rate constants (kobs) were 0.0931 and 0.1938 min&minus;1 at pH 6.0 in the UV/PDS system. The sulfate radical (SO4&bull;&minus;) and hydroxyl radical (&bull;OH) were identified as the major reactive radicals. The pH-dependent reaction rate constants of ACY and ATL with &bull;OH and SO4&bull;&minus; were measured via the competing kinetics. Meanwhile, the contributions of &bull;OH and SO4&bull;&minus; for ACY and ATL degradation were calculated by the radical steady-state hypothesis, and the results revealed that SO4&bull;&minus; occupied a decisive position (&gt;84.5%) for the elimination of ACY and ATL. The contribution of &bull;OH became more significant with the increasing pH, while SO4&bull;&minus; was still dominant. Moreover, ACY and ATL degradation performance were systematically evaluated via the experiments and Kintecus model under different operational parameters (Cl&minus;, Br&minus;, HCO3&minus;, NOM, etc.) in the UV/PDS process. Furthermore, the plausible reaction pathways of ACY and ATL were elucidated based on the Fukui function theory and ultra-performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) analysis. The UV/PDS process has been demonstrated to be an efficient and potential application for micropollutants mitigation

    Longitudinal trajectories of depressive symptoms: the role of multimorbidity, mobility and subjective memory

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    Abstract Background The high prevalence of depression among older people in China places a heavy burden on the health system. Multimorbidity, mobility limitation and subjective memory impairment are found to be risk indicators for depression. However, most studies on this topic focused on depression at a single point in time, ignoring the dynamic changes in depressive symptoms and the relationship between the trajectories and these three conditions. Therefore, we aimed to identify distinct trajectories of depressive symptoms in older people and investigate their associations with multimorbidity, mobility limitation and subjective memory impairment. Methods Data was drawn from China Health and Retirement Longitudinal Study conducted during 2011–2018. A total of 5196 participants who completed 4 visits, conducted every 2–3 years were included in this study. Group-based trajectory modeling was conducted to identify distinct trajectories of depressive symptoms z-scores. Multinomial logistic regression was used to investigate the relationships. Results Four distinct trajectories of depressive symptoms z-scores were identified, labeled as persistently low symptoms (68.69%, n = 3569), increasing symptoms (12.14%, n = 631), decreasing symptoms (14.05%, n = 730) and persistently high symptoms (5.12%, n = 266). Participants with multimorbidity had unfavorable trajectories of depressive symptoms compared with those without multimorbidity, with adjusted odds ratios (95% CIs) of 1.40 (1.15, 1.70), 1.59 (1.33, 1.90) and 2.19 (1.65, 2.90) for the increasing symptoms, decreasing symptoms and persistently high symptoms, respectively. We also observed a similar trend among participants with mobility limitations. Compared with participants who had poor subjective memory, participants with excellent/very good/good subjective memory had a lower risk of developing unfavorable trajectories of depressive symptoms. The adjusted odds ratios (95% CIs) of the increasing symptoms, decreasing symptoms and persistently high symptoms were 0.54 (0.40, 0.72), 0.50 (0.38, 0.65) and 0.48 (0.31, 0.73), respectively. Conclusions Multimorbidity, mobility limitation and subjective memory impairment were found to be potential risk factors for unfavorable depression trajectories

    Insights into the photocatalytic ozonation over Ag2O-ZnO@g-C3N4 composite: Cooperative structure, degradation performance, and synergistic mechanisms

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    In this work, Ag2O and ZnO modified g-C3N4 (Ag2O-ZnO@CNx) catalysts were fabricated by a simple precipitation-reflux method and employed for visible-light-driven photocatalytic ozonation process towards oxalic acid (OA) degradation. A series of characterizations such as XRD, TEM, XPS, UV-vis DRS, PL, Mott- Schottky were conducted to investigate the impact of loading Ag2O-ZnO on the microstructure and catalytic properties of catalysts. It was noteworthy that the mesoporous and backbone structure did not perceptibly change after doping Ag2O-ZnO to g-C3N4. Moreover, the separation of photogenerated e h+ pairs, the mobility of e transfer, and the photocatalytic ozonation performance were improved with the increase in doping amount of g-C3N4. Amongst, the [email protected] achieved 83.43% of OA removal efficiency and the highest k value (0.0311 min 1), showing an excellent synergistic effect (synergy index η = 10.37) in this coupling system. Moreover, the [email protected] exhibited satisfactory reusability for multiple consecutive cycles (≥5). Through the radical scavenger experiments and ESR spectra, the reactive species including h+, e , O2¿ , 1O2 and ¿OH were verified to play an important role in PhOx system. Accordingly, an empirical kinetic model was established to predict OA concentration with the given operational parameters. The synergistic mechanism of OA degradation in the PhOx system was also proposed. Overall, the results presented a new insight into the application of PhOx process in water treatment
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