49 research outputs found

    Fast Repetition Rate Fluorometry (FRRF) Derived Phytoplankton Primary Productivity in the Bay of Bengal

    Get PDF
    The approach of fast repetition rate fluorometry (FRRF) requires a conversion factor (Φe : C/nPSII) to derive ecologically-relevant carbon uptake rates (PPz,t). However, the required Φe : C/nPSII is commonly measured by 14C assimilation and varies greatly across phytoplankton taxonomy and environmental conditions. Consequently, the use of FRRF to estimate gross primary productivity (GPz,t), alone or in combination with other approaches, has been restricted by both inherent conversion and procedural inconsistencies. Within this study, based on a hypothesis that the non-photochemical quenching (NPQNSV) can be used as a proxy for the variability and magnitude of Φe : C/nPSII, we thus proposed an independent field model coupling with the NPQNSV-based Φe : C/nPSII for FRRF-derived carbon, without the need for additional Φe : C/nPSII in the Bay of Bengal (BOB). Therewith, this robust algorithm was verified by the parallel measures of electron transport rates and 14C-uptake PPz,t. NPQNSV is theoretically caused by the effects of excess irradiance pressure, however, it showed a light and depth-independent response on large spatial scales of the BOB. Trends observed for the maximum quantum efficiency (Fv/Fm), the quantum efficiency of energy conversion (Fq′/Fm′) and the efficiency of charge separation (Fq′/Fv′) were similar and representative, which displayed a relative maximum at the subsurface and were collectively limited by excess irradiance. In particular, most observed values of Fv/Fm in the BOB were only about half of the values expected for nutrient replete phytoplankton. FRRF-based estimates of electron transport at PSII (ETRRCII) varied significantly, from 0.01 to 8.01 mol e− mol RCII−1 s−1, and showed profound responses to depth and irradiance across the BOB, but fitting with the logistic model. N, P, and irradiance are key environmental drivers in explaining the broad-scale variability of photosynthetic parameters. Furthermore, taxonomic shifts and physiological changes may be better predictors of photosynthetic parameters, and facilitate the selection of better adapted species to optimize photosynthetic efficiency under any particular set of ambient light condition

    Size-Fractionated Filtration Combined with Molecular Methods Reveals the Size and Diversity of Picophytoplankton

    No full text
    In this study, flow cytometry (FCM) and size-fractionated filtration, together with high-throughput molecular sequencing methods (SM), were used to investigate picophytoplankton. A particle separation filter and a higher-throughput sequencing method were used to evaluate the composition of a euphotic zone of picophytoplankton—especially picoeukaryotic phytoplankton—in the Western Pacific, and the results of flow cytometry, which is a classic way to detect picophytoplankton, were used as a standard to evaluate the reliability of the results of the SMs. Within a water column of 200 m, six water depths (5, 25, 50, 113 (DCM), 150, and 200 m) were established. In order to further study the particle size spectra of the picophytoplankton, size-fractionated filtration was used to separate water samples from each water depth into three particle size ranges: 0.2–0.6, 0.6–1.2, and 1.2–2 μm. A total of 36 (6 × 3 × 2) samples were obtained through PCR amplification of the 18S rRNA V4 hypervariable region and 16S rRNA, which were biased toward phytoplankton plastids, and then high-throughput sequencing was performed. The estimation of the picophytoplankton diameter relied on forward scattering (FSC) through FCM. The estimation of the vertical distribution and diameter of the picophytoplankton using the SM was consistent with the results with FCM; thus, we believe that the estimation of picophytoplankton composition with the SM has value as a reference, although the size-fractionated filtration seemed to cause some deviations. In addition to Prochlorococcus and Synechococcus, the SM was used to evaluate the composition of picoeukaryotic phytoplankton, which mainly included Prymnesiophycea (Haptophyta) (38.15%), Cryptophyceae (Cryptophyta) (22.36%), Dictyochophyceae (Chrysophyta) (12.22%), and Mamiellophyceae (Chlorophyta) (3.31%). In addition, the SM also detected Dinophyceae (Dinoflagellata) (11.69%) sequences and a small number of Bacillariophyceae (Diatom) (1.64%) sequences, which are generally considered to have large particle sizes. The results of the SM also showed that the picoeukaryotic phytoplankton were not evenly distributed in the euphotic layer, and the vertical distributions of the different picoeukaryotic phytoplankton were different. An analysis of correlations with environmental factors showed that temperature was the main environmental factor controlling the vertical distribution of picophytoplankton

    Picophytoplankton size and biomass around equatorial eastern Indian Ocean

    No full text
    The cellular size and biomass of picophytoplankton were studied by flow cytometer during spring monsoon (March-May of 2015) in equatorial eastern Indian Ocean. We established an empirical relationship between forward scatter and cellular size to address the size and biomass of picophytoplankton. Results indicated that mean cell diameter of Prochlorococcus (0.60 mu m) was the smallest, and then followed by Synechococcus (0.98 mu m) and picoeukaryotic phytoplankton (1.05 mu m). Thereafter, the biomass converted by abundance reached 0.64 mu g center dot C center dot L-1 for Prochlorococcus, 0.34 mu g center dot C center dot L-1 for Synechococcus, and 0.20 mu g center dot C center dot L-1 for picoeukaryotic phytoplankton. Additionally, the distinct biomass contribution of picophytoplankton appeared to be affected by abundance, but not changes in cellular size. Vertically, the cellular sizes of picophytoplankton were remarkably small in upper waters, which was predominantly controlled by the nutrient availability. In contrast, they were larger in deeper waters, which was primarily attributed to the combined effects of low temperature and reduced light availability. Spatially, under the influence of high nutrient concentration induced by the different circulations and coastal upwelling, slightly high carbon biomass of picophytoplankton was observed around the coastal zones of Sri Lanka island and Sumatra, as well as the southern Bay of Bengal

    Modified Backtracking Search Optimization Algorithm Inspired by Simulated Annealing for Constrained Engineering Optimization Problems

    No full text
    The backtracking search optimization algorithm (BSA) is a population-based evolutionary algorithm for numerical optimization problems. BSA has a powerful global exploration capacity while its local exploitation capability is relatively poor. This affects the convergence speed of the algorithm. In this paper, we propose a modified BSA inspired by simulated annealing (BSAISA) to overcome the deficiency of BSA. In the BSAISA, the amplitude control factor (F) is modified based on the Metropolis criterion in simulated annealing. The redesigned F could be adaptively decreased as the number of iterations increases and it does not introduce extra parameters. A self-adaptive ε-constrained method is used to handle the strict constraints. We compared the performance of the proposed BSAISA with BSA and other well-known algorithms when solving thirteen constrained benchmarks and five engineering design problems. The simulation results demonstrated that BSAISA is more effective than BSA and more competitive with other well-known algorithms in terms of convergence speed

    Multi-Objective Optimization for Selecting and Siting the Cost-Effective BMPs by Coupling Revised GWLF Model and NSGAII Algorithm

    No full text
    Best management practices (BMPs) are an effective way to control water pollution. However, identification of the optimal distribution and cost-effect of BMPs provides a great challenge for watershed policy makers. In this paper, a semi-distributed, low-data, and robust watershed model, the Revised Generalized Watershed Loading Function (RGWLF), is improved by adding the pollutant attenuation process in the river channel and a bank filter strips reduction function. Three types of pollution control measures—point source wastewater treatment, bank filter strips, and converting farmland to forest—are considered, and the cost of each measure is determined. Furthermore, the RGWLF watershed model is coupled with a widely recognized multi-objective optimization algorithm, the non-dominated sorting genetic algorithm II (NSGAII), the combination of which is applied in the Luanhe watershed to search for spatial BMPs for dissolved nitrogen (DisN). Fifty scenarios were finally selected from numerous possibilities and the results indicate that, at a minimum cost of 9.09 × 107 yuan, the DisN load is 3.1 × 107 kg and, at a maximum cost of 1.77 × 108 yuan, the total dissolved nitrogen load is 1.31 × 107 kg; with the no-measures scenario, the DisN load is 4.05 × 107 kg. This BMP optimization model system could assist decision-makers in determining a scientifically comprehensive plan to realize cost-effective goals for the watershed

    Long non-coding RNA XIST regulates PTEN expression by sponging miR-181a and promotes hepatocellular carcinoma progression

    No full text
    Abstract Background Tumor metastasis often occurs in hepatocellular carcinoma (HCC) and influences the patient’s prognosis, and microRNAs are reported to play key roles in tumor metastasis. This study was conducted to explore the effect of microRNAs on HCC metastasis. Methods The levels of miR-181a in HCC tissues, adjacent tissues, metastatic HCC tissues, and non-metastatic HCC tissues at different stages were determined by qRT-PCR. Effect of miR-181a on the proliferation, invasion, and metastasis of HCC cells was estimated by cell counting kits-8 (CCK-8), wound-healing, and Transwell assays. Software analysis and luciferase assays were used to explore the target gene of miR-181a. Results MiR-181a was up-regulated in HCC tissues and its expression level in metastatic HCC tissues was much higher than in non-metastasis samples. PTEN was found to be a target gene of miR-181a. MiR-181a had multiple binding sites with the long non-coding RNA (lncRNA) XIST. The regulation of miR-181a on PTEN was mediated by lncRNA XIST. The proliferation and invasion of cells with siXIST were significantly enhanced compared with those of control cells, while knockdown of miR-181a abolished the enhancing effects. Conclusions MiR-181a can promote HCC metastasis by targeting PTEN, which is regulated by lncRNA XIST

    Optimization of Cold Pressing Process Parameters of Chopped Corn Straws for Fuel

    No full text
    Pressed condensation is a key process before the reclamation of loose corn straws. In this study, the effects of stabilization time on the relaxation density and dimensional stability of corn straws were studied firstly, and then the stabilization time was determined to be 60 s by comprehensively considering the compression effect, energy consumption, efficiency and significance. On this basis, the effects of the water content (12%, 15%, 18%), ratio of pressure maintenance time to stabilization time (0, 0.5, 1), maximum compression stress (60.4, 120.8, 181.2 kPa) and feeding mass (2.5, 3, 3.5 kg) on the relaxation density, dimensional stability coefficient, and specific energy consumption of post-compression straw blocks were investigated by the Box–Behnken design. It was found that the water content, ratio of pressure maintenance time to stabilization time, maximum compression stress, and feeding mass all very significantly affected the relaxation density, dimensional stability coefficient and specific energy consumption. The interaction between water content and maximum compression stress significantly affected both relaxation density and specific energy consumption. The interaction between the ratio of pressure maintenance time to stabilization time and feeding mass significantly affected the dimensional stability coefficient. The factors and the indices were regressed by quadratic equations, with the coefficients of determination larger than 0.97 in all equations. The optimized process parameters were water content of 13.63%, pressure maintenance time of 22.8 s, strain maintenance time of 37.2 s, maximum compression stress of 109.58 kPa, and raw material feeding mass of 3.5 kg. Under these conditions, the relaxation density of cold-pressed straw blocks was 145.63 kg/m3, the dimensional stability coefficient was 86.89%, and specific energy consumption was 245.78 J/kg. The errors between test results and predicted results were less than 2%. The low calorific value of cold-pressed chopped corn straw blocks was 12.8 MJ/kg. Through the situational analysis method based on the internal and external competition environments and competition conditions (SWOT analysis method), the cold-pressed chopped corn straw blocks consumed the lowest forming energy consumption than other forming methods and, thus, are feasible for heating by farmers. Our findings may provide a reference for corn straw bundling, cold-press forming processes and straw bale re-compressing

    circ_0000045 promotes proliferation, migration, and invasion of head and neck squamous cell carcinomas via regulating HSP70 and MAPK pathway

    No full text
    Abstract Objective Head and neck squamous cell carcinoma (HNSCC) is one severe malignancy driven by complex cellular and signaling mechanisms. However, the roles of circular RNAs (circRNAs) in HNSCC’s development remains poorly understood. Therefore, this study investigated the functions of differentially expressed circRNAs in regulating HNSCC cell functions. Methods Differentially expressed circRNAs were characterized through RNA sequencing in HNSCC tissues. CircRNA’s identity was then confirmed using RT-PCR and Sanger’s sequencing. Next, expression levels of circRNA and mRNA were detected by qRT-PCR, after which protein abundances were measured by Western blotting. Subsequently, the proliferation, migration, and invasion of HNSCC cells was assessed by MTS, wound healing, and Transwell system, respectively, followed by identification of circRNA-binding proteins in HNSCC cells by circRNA pull-down, coupled with mass spectrometry. Results Great alterations in circRNA profiles were detected in HNSCC tissues, including the elevated expression of circ_0000045. As observed, silencing of circ_0000045 effectively repressed the proliferation, migration, and invasion of HNSCC cell lines (FaDu and SCC-9). Contrarily, circ_0000045’s overexpression promoted the proliferation, migration, and invasion in FaDu and SCC-9 cells. Results also showed that circ_0000045 was associated with multiple RNA-binding proteins in HNSCC cells, such as HSP70. Moreover, circ_0000045 knockdown enhanced HSP70 expression and inhibited JNK2 and P38’s expression in HNSCC cells, which were oppositely regulated by circ_0000045’s overexpression. Conclusion The high expression of circ_0000045; therefore, promoted cell proliferation, migration, and invasion during HNSCC’s development through regulating HSP70 protein and mitogen-activated protein kinase signaling

    Effect of Childhood Trauma on Aggressive Behavior in Stable Schizophrenia Patients: the Chain Mediating Effect of Self-esteem and Resilience

    Get PDF
    Background Among people with various mental illnesses, those with schizophrenia have the highest incidence of aggressive behavior, which not only disturbs the medical environment, but also poses a great threat to family stability and social harmony. Previous regression analysis studies have shown that childhood trauma, self-esteem and resilience are influencing factors of aggressive behavior in schizophrenia patients, but few studies have explored the internal relationship between these four variables. Objective To explore the relationship between childhood trauma, self-esteem, resilience and aggressive behavior in schizophrenic patients using a self-constructed chain mediation model, and to clarify its internal mechanism. Methods A convenience sample of stable schizophrenia inpatients were selected from Daqing Third Hospital and Chifeng Anding Hospital from March 2021 to July 2022. A survey was conducted with them using a questionnaire consisting of general information questionnaire, Positive and Negative Symptom Scale (PANSS) , Childhood Trauma Questionnaire-Short Form (CTQ-SF) , Connor-Davidson Resilience Scale (CD-RISC) , Self-esteem Scale (SES) , and Aggressive Questionnaire (AQ) . Pearson correlation analysis was used to explore the correlation of AQ score with CTQ-SF, CD-RISC and SES scores. Multiple linear regression analysis was used to explore the influencing factors of aggressive behavior. AMOS 24.0 was used to construct the chain mediation model. The mediation effect of the chain mediation model was tested using Bootstrap method. Results Three hundred and ten cases attended the survey, and 300 of them (96.8%) who responded effectively were finally included for analysis. The average scores of PANSS, CTQ-SF, SES, CD-RISC and AQ were (18.4±3.7) , (49.7±13.5) , (26.9±6.9) , (55.2±15.5) and (84.3±19.8) , respectively. Multiple linear regression analysis showed that childhood trauma〔B=0.551, 95%CI (0.421, 0.681) , P<0.001〕, self-esteem〔B=-0.661, 95%CI (-0.908, -0.413) , P<0.001〕and resilience〔B=-0.448, 95%CI (-0.561, -0.335) , P<0.001〕 were influencing factors of aggressive behavior. Pearson correlation analysis revealed that CTQ-SF scores were positively correlated with AQ scores (r=0.695, P<0.01) and negatively correlated with SES scores and CTQ-SF scores (r=-0.524, P<0.01; r=-0.565, P<0.01) ; SES scores were negatively correlated with AQ scores (r=-0.607, P<0.01) and positively correlated with CD-RISC scores (r= 0.522, P<0.01) ; the CD-RISC score was negatively correlated with the AQ scores (r=-0.681, P<0.01) . The chain mediation model test results showed that the goodness-of-fit of the model was good. Bootstrap test showed that the 95%CI of each mediation path did not include 0, and the mediation effect was significant. The overall effect of childhood trauma on aggressive behavior was significant〔β=0.810, 95%CI (0.743, 0.871) , P<0.001〕. The indirect effect of childhood trauma on aggressive behavior, that is, acting through the mediators of self-esteem and resilience, was significant〔β=0.473, 95%CI (0.362, 0.598) , P<0.001〕. The direct effect of childhood trauma on aggressive behavior was significant〔β=0.377, 95%CI (0.179, 0.485) , P<0.001〕. Conclusion Self-esteem and resilience play a chain mediating role between childhood trauma and aggressive behavior in patients with schizophrenia. In the future, a risk prediction model of aggressive behavior in schizophrenia patients can be constructed to assess the risk of aggressive behavior, which is contributive to early identification and management of those at risk of aggression, thereby reducing or preventing the occurrence of aggressive behavior

    Comparative Study on the Chemical Components and Gastrointestinal Function on Rats of the Raw Product and Licorice-Simmered Product of Polygala tenuifolia

    No full text
    The root of Polygala tenuifolia Willd. (Polygalaceae) (PT) has been listed as a nootropic, anti-inflammatory, and antipsychotic medicine that can cure insomnia. Raw PT (RPT) is toxic and must be processed before clinical use. Licorice-simmered PT (LPT) is one of the most common processed products. We conducted this study in order to investigate the differences in chemical components and gastrointestinal function between RPT and LPT. We used principal component analysis (PCA) and quantitative analysis to study the differences in the chemical components. Animal experiments were conducted to evaluate the effects of PT on the gastrointestinal function of rats before and after simmering. Pathological sections of gastrointestinal tissues, serum hormone levels, and inflammatory cytokines were observed. The PCA results demonstrated that obvious separation was achieved between the RPT and LPT samples. Tenuifoliside B (TFSB), 3,6’-disinapoyl sucrose (DSS), tenuifoliose A (TFOA), tenuifoliose H (TFOH), onjisaponin B (OJB), onjisaponin Z (OJZ), and total saponins levels were decreased after licorice processing, while glomeratose A (GA) and 3,4,5-trimethoxycinnamic acid (TMCA) levels were markedly increased. Compared to the control group, the RPT groups exhibited dramatically lower levels of gastrin (GAS), motilin (MTL), and substance P (SP) and markedly higher levels of vasoactive intestinal peptide (VIP) and somatostatin (SS), but the LPT groups exhibited no significant differences in the above indexes. The levels of interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-α (TNF-α) in gastrointestinal tissue were markedly increased in the low RPT (L-RPT), high RPT (H-RPT), and H-LPT groups, showing a certain inflammatory effect, but the inflammatory effect in the L-LPT group was relatively weak. Licorice simmering can effectively reduce the inhibitory effect of RPT on gastrointestinal function in rats and reduce damage to gastrointestinal tissue. This study provides a scientific basis for research on the processing mechanism and clinical application of PT
    corecore