Competition Curves Research Articles

Research on the mechanism of coal adsorption of CO2 hindering oxygen

This paper investigates the inhibitory effect of CO2 on oxygen adsorption during the low-temperature oxidation of coal. Taking the example of Tingnan coal, the physical adsorption barriers of CO2 during coal oxidation at different temperatures were analyzed in terms of competitive adsorption curves, adsorption capacity, adsorption selectivity and diffusion coefficients using a combination of indoor experiments and molecular simulations. It is proposed that the competitive adsorption advantage of CO2 is significantly greater than that of O2, and it is negatively correlated with temperature. Additionally, the variations of aliphatic gas-phase products are evident during the pre-oxidation temperature stages. When the pre-oxidation temperature exceeds 70 °C, the amounts of CH4 and C2H4 released increase with the pre-oxidation temperature, and the inhibitory effect of injected CO2 deteriorates. The simulation results validate the experimental conclusions and are in line with the actual situation, providing auxiliary optimization and guidance for coal mine fire prevention work.

Competition and regional Phillips curve: Evidence from China.

The product market competition affects the non-neutrality of monetary policy. This paper quantitatively assesses its impact on the slope of the Phillips curve through the channels of nominal and real rigidity. We build a New Keynesian model using the Kimball aggregator and the Calvo staggered pricing scheme. We show that a more competitive market environment has opposite effects on the slope of the Phillips curve by increasing the real rigidity and lowering the nominal rigidity. We then estimated the model using regional data of China. The Bayesian estimation shows that the response of inflation-output trade-off is larger in the region with a high degree of competition. Counterfactual experiments demonstrate that nominal rigidity has a dominant role and accounts for the majority of the difference in the Phillips curve, while the contribution of real rigidity is relatively minor. Our results highlight the key role of nominal rigidity in determining the inflation-output dynamics.

Predicting the risk of variceal rehemorrhage in cirrhotic patients with portal vein thrombosis: A two-center retrospective study.

Although portal vein thrombosis (PVT) was thought to deteriorate portal hypertension and contribute to poor prognosis, risk stratification remains unclear. This study aimed to evaluate its effect on the risk of variceal rehemorrhage and to develop a competitive risk model in cirrhotic patients with PVT. Cirrhotic patients with and without PVT admitted for acute variceal hemorrhage were retrospectively included after matching (1:1) for age, gender and etiology of cirrhosis from two tertiary centers with 1-year follow-up. Those with PVT were subsequently divided into the training and validation cohorts. Cox regression analysis was performed to identify risk factors and develop a competitive risk model, of which the predictive performance and optimal decision threshold were evaluated by C-index, competitive risk curves, calibration curves and decision curve analysis. Among 398 patients, PVT significantly increased the variceal rehemorrhage risk. Multivariate Cox regression analysis identified that the Child-Turcotte-Pugh score (P = 0.013), chronicPVT (P = 0.025), C-reactive protein (P < 0.001), and aspartate aminotransferase (P = 0.039) were independently associated with variceal rehemorrhage, which were incorporated into the competitive risk model, with high C-index (0.804 and 0.742 of the training and validation cohorts, respectively), risk stratification ability, and consistency. The optimal decision range of the threshold probability was 0.2-1.0. We confirmed the adverse effect of PVT on variceal rehemorrhage and developed a competitive risk model for variceal rehemorrhage in cirrhotic patients with PVT, which might be conveniently used for clinical decision-making.

Magnetic Janus micromotors for fluorescence biosensing of tacrolimus in oral fluids

Tacrolimus (FK506) is a macrolide lactone immunosuppressive drug that is commonly used in transplanted patients to avoid organ rejection. FK506 exhibits high inter- and intra-patient pharmacokinetic variability, making monitoring necessary for organ graft survival. This work describes the development of a novel bioassay for monitoring FK506. The bioassay is based on using polycaprolactone-based (PCL) magnetic Janus micromotors and a recombinant chimera receptor that incorporates the immunophilin tacrolimus binding protein 1A (FKBP1A) tagged with Emerald Green Fluorescent Protein (EmGFP). The approach relies on a fluorescence competitive bioassay between the drug and the micromotors decorated with a carboxylated FK506 toward the specific site of the fluorescent immunophilin. The proposed homogeneous assay could be performed in a single step without washing steps to separate the unbound receptor. The proposed approach fits the therapeutic requirements, showing a limit of detection of 0.8 ng/mL and a wide dynamic range of up to 90 ng/mL. Assay selectivity was evaluated by measuring the competitive inhibition curves with other immunosuppressive drugs usually co-administered with FK506. The magnetic propulsion mechanism allows for efficient operation in raw samples without damaging the biological binding receptor (FKBP1A-EmGFP). The enhanced target recognition and micromixing strategies hold considerable potential for FK506 monitoring in practical clinical use.

Design and development of a lanthanide-labeled immunochromatographic strip for simultaneous detection of morphine, methamphetamine and ketamine in hair.

Colloidal gold immunoassay is the most widely used method in the field of drug detection. However, this method often has poor quantitative identification ability and low analytical sensitivity, which is not suitable for the analysis of hair poisoning ingredients. In order to solve these limitations, we developed an immunochromatographic test strip for simultaneously screening multiple drugs in this study. This hand-held test strip used fluorescent nanoparticles loaded with lanthanide chelates as the signal carrier of fluorescence reading, and conducted quantitative testing of various drugs based on the competitive immune reaction between the analyte and antigen. Under the optimal conditions, the competition curves of morphine (MOP), methamphetamine (MET) and ketamine (KET) were obtained on a single band. The detection limit (LOD) of this analytical method was 100-1000 times lower than that of colloidal gold test strips. The detection limits of MOP, MET and KET were 0.06 ng mL-1, 0.1 ng mL-1 and 1.0 ng mL-1, respectively. No cross-reaction was observed when morphine, methamphetamine and ketamine were tested simultaneously with this method. And 184 hair samples were tested simultaneously, and the detected amount was very close to the results of LC-MS. The immunochromatographic strip showed good stability in repeated tests, and the coefficient of variation was less than 15%. Fluorescence immunochromatography strips and handheld strip readers have the characteristics of portability, speed, ease of operation and high sensitivity, and may become powerful tools for screening drug abuse in hair in forensic medicine.

A Cavity-Tailored Metal-Organic Tetrahedral Nanocage and Gas Adsorption Property.

Porous organometallic nanomaterials are a new class of materials based on a three-dimensional structure. They have excellent applications in different fields, but their applications in gas storage and separation have not been fully developed. CO2 adsorption storage and hydrocarbon separation has been a challenging industrial problem. Several typical molecular adsorbents have been used to study the separation, but the problems of long-term stability, high selectivity and synthetic complexity of these adsorbents remain to be solved. Here, we have designed and synthesized tetrahedral metal supramolecular nanocage with custom cavities based on the unique rigid structure of triptycene derivatives. Using the unique discrete porous structure of tetrahedral metal nanocages, the gas adsorption and separation performance of the metal supramolecular nanocage was investigated. By analyzing the adsorption and desorption isotherms and the multi-component competitive adsorption curves, we noticed that the tetrahedral supramolecular nanocages had good CO2 storage capacity and good separation capacity for C2H2/CO2 and C2H2/N2. All these indicate that porous organic metal nanomaterials are expected to be a new energy saving separation material.

A Method for Screening Proteases That Can Specifically Hydrolyze the Epitope AA83-105 of αs1-Casein Allergen.

Milk protein hydrolysates are common in infant formula, but some of them retain allergenicity due to incomplete hydrolysis of the epitopes for milk allergens. This study explored a method for screening proteases that could specifically hydrolyze the epitope of αs1-casein allergen. Firstly, the αs1-casein epitope AA83-105 was synthesized by the solid-phase synthesis method. Then, after purification and identification, the complete antigen was prepared through coupling with bovine serum albumin (BSA) and was used to raise monoclonal antibodies (mAb) in BALB/c mice. Additionally, an indirect competitive-enzyme-linked immunosorbent assay (icELISA) was established. The mAb raised against αs1-casein protein was used as a control. The results showed that the purity of the synthetic epitope was &gt;90%, and the coupling rate with BSA was 6.31. The mAb subtype is IgG1, with a titer of 1:320,000. The mAb reacted specifically with αs1-casein but did not cross-react with soybean protein. The linear regression equation of the competitive inhibition curve was y = -9.22x + 100.78 (R2 = 0.9891). The detection limit of icELISA method was more sensitive, and the method showed good accuracy and repeatability. The amounts of antigen residues in papain protease hydrolysates were relatively small, and the epitope fragment was detected in papain hydrolysate via mass spectrometry. This study provides ideas and methods for screening proteases that specifically hydrolyze the epitopes of milk allergens and also provides a superior foundation for the development of an advanced hypoallergenic formula.

Development of a Linear Immobilization Carrier-Based Immunoassay for Aflatoxin.

We explored the feasibility of developing immunoassay technology with a linear carrier, to develop a simpler and cheaper rapid immunoassay technology. We selected aflatoxins as an example for research, as they are a group of highly toxic and carcinogenic compounds representing a worldwide threat to human health and life. With a non-competitive immunoassay, we detected and evaluated the effect of 28 different linear materials on antibody immobilization. Mercerized cotton and Dyneema line were chosen from the linear materials for further comparison using a competitive immunoassay, because both showed high-signal values and relatively low background noise. The results showed the sensitive IC50 of mercerized cotton as the reaction carrier was 0.33 ng/mL, and the linear range was 0.16~3.25 ng/mL. The sensitivity using Dyneema line as the reaction carrier was 1.16 ng/mL. The competitive curves of four sample matrices were established to evaluate the stability of the detection system; these were basically consistent with those without sample matrices. In conclusion, both mercerized cotton and Dyneema, will be suggested for the novel development of linear immobilization carrier-based immunoassays for other analytes, and especially to construct inexpensive and easy-to-obtain biological and environmental analytical technologies and biosensors.

Adaptation of selected models for describing competitive per- and polyfluoroalkyl substances breakthrough curves in groundwater treated by granular activated carbon

Granular activated carbon (GAC) has proven to be a successful technology for per- and polyfluoroalkyl substances (PFAS) removal from contaminated drinking water supplies. Proper design of GAC treatment relies upon characterization of media service-life, which can change significantly depending on the PFAS contamination, treatment media, and water quality, and is often determined by fitting descriptive models to breakthrough curves. However, while common descriptive breakthrough models are favored for their ease-of-use, they have a significant shortcoming in that they are not able to properly fit PFAS desorption in competitive sorption scenarios. The present work adapts three common descriptive models to fit competitive PFAS breakthrough curves from a GAC pilot study. The adapted and original models were fit to the experimental breakthrough curves for 12 common PFAS and evaluated using adjusted R2 and reduced χ2 values. This study found that the novel adaptation of the common descriptive models successfully accounted for desorption of PFAS compounds from the GAC, accurately describing increased exposure risks due to elevated effluent levels during desorption without significantly increasing the complexity of implementing the models.

Competition and Regional Phillips Curve

Competition and Regional Phillips Curve

Similarities and differences upon binding of naturally occurring Δ9-tetrahydrocannabinol-derivatives to cannabinoid CB1 and CB2 receptors

We have here assessed, using Δ9-tetrahydrocannabinol (Δ9-THC) for comparison, the effect of Δ9-tetrahydrocannabinolic acid (Δ9-THCA) and of Δ9-tetrahydrocannabivarin (Δ9-THCV) that is mediated by human versions of CB1, CB2, and CB1-CB2 receptor functional units, expressed in a heterologous system. Binding to the CB1 and CB2 receptors was addressed in living cells by means of a homogeneous assay. A biphasic competition curve for the binding to the CB2 receptor, was obtained for Δ9-THCV in cells expressing the two receptors. Signaling studies included cAMP level determination, activation of the mitogen-activated protein kinase pathway and ß-arrestin recruitment were performed. The signaling triggered by Δ9-THCA and Δ9-THCV via individual receptors or receptor heteromers disclosed differential bias, i.e. the bias observed using a given phytocannabinoid depended on the receptor (CB1, CB2 or CB1-CB2) and on the compound used as reference to calculate the bias factor (Δ9-THC, a selective agonist or a non-selective agonist). These results are consistent with different binding modes leading to differential functional selectivity depending on the agonist structure, and the state (monomeric or heteromeric) of the cannabinoid receptor. In addition, on studying Gi-coupling we showed that Δ9-THCV and Δ9-THCA and Δ9-THCV were able to revert the effect of a selective CB2 receptor agonist, but only Δ9-THCV, and not Δ9-THCA, reverted the effect of arachidonyl-2′-chloroethylamide (ACEA 100 nM) a selective agonist of the CB1 receptor. Overall, these results indicate that cannabinoids may have a variety of binding modes that results in qualitatively different effects depending on the signaling pathway that is engaged upon cannabinoid receptor activation

Improvement of the population competition model

Classic population competition model with fixed parameters can only be used under the condition of constant living environment, which is impossible in real life. So it has little practical significance in some cases. In this paper, the model will be improved so that it can be used in a changeable living environment. The objective is to establish the relationship between model parameters and independent variables of external conditions with multivariate regression. Growth curves of populations competing with each other are obtained by piecewise prediction. The data used in the regression are obtained by doing experiments. This paper will take wood rot fungus as an example to explain how to establish the relationship by doing experiments, and apply the new model and the classic one with artificial simulation data, so that two groups of predicted population competition curves are obtained. It has been found that the new model can more accurately describe population competition in the case of severe fluctuations in external environment, while the classic model has obvious errors. Finally, this paper briefly describes other advantages of the new model.

Nitrate removal by quaternized mesoporous silica gel in ternary anion solutions: Flow-through column experiments and artificial neural network modeling

The aim of this study was to examine nitrate removal by quaternized silica gel (q-SG) in ternary solutions of nitrate, phosphate, and sulfate under flow-through column conditions. q-SG was synthesized by grafting dimethyloctyl[3-(trimethoxysilyl)propyl] ammonium chloride on silica gel. Fixed-bed column experimental conditions (N = 15) were designed using central composite design to examine dynamic removal behaviors of competing anions in columns containing q-SG. During the experiments, influent solution containing ternary anions of nitrate, phosphate, and sulfate was injected into flow-through columns. In the effluent, the ternary anions along with chloride were monitored to obtain competitive breakthrough curves. Column experiments demonstrated the dynamic and competitive removal behaviors of anions during adsorption and leaching in the columns. Artificial neural network (ANN) model was developed based on the column experimental data to predict the removal rates of anions in the column experiments. In the model development, influent concentrations of nitrate, phosphate, and sulfate were selected as three variables in the input layer, whereas removal rates of nitrate, phosphate, and sulfate were chosen as three variables in the output layer. The developed ANN model with topology 3:8:9:3 (three input variables, eight neurons in the first hidden layer, nine neurons in the second hidden layer, and three output variables) could simultaneously predict the removal rates of anions in column experiments.

Selective Discovery of GPCR Ligands within DNA-Encoded Chemical Libraries Derived from Natural Products: A Case Study on Antagonists of Angiotensin II Type I Receptor.

Natural products have failed to meet the urgent need for drug discovery in recent decades due to limited resources, necessitating new strategies for re-establishing the key role of natural products in hit screening. This work introduced DNA-encoding techniques into the synthesis of phenolic acid-focused libraries containing 32 000 diverse compounds. Online selection of the library using immobilized angiotensin II type I receptor (AT1R) resulted in seven phenolic acid derivatives. The half-maximal concentration (IC50) of hit 1 for the right shift of the [125I]-Sar1-AngII competition curve was 19.6 nM. Pharmacological examination of renovascular hypertensive rats demonstrated that hit 1 significantly lowered the blood pressure of the animals without changing their heart rates. These results were used to create a general strategy for rapid and unbiased discovery of hits derived from natural products with high throughput and efficiency.

Coordinative mediation of the response to alarm pheromones by three odorant binding proteins in the green peach aphid Myzus persicae

Odorant binding proteins (OBPs) play an essential role for insect chemosensation in insect peripheral nervous systems of antennae. Each antennal sensilla contains more than one OBP at high concentrations but the interactions and cooperation between co-localized OBPs are rarely reported. In present study, we cloned, expressed and purified eight OBPs of the green peach aphid Myzus persicae. The effects of knocking down the expression of these OBP genes by RNAi on the electrophysiological and behavioural responses of M. persicae to the aphid alarm pheromone, (E)-β-farnesene (EβF) were investigated. The results showed that the aphids could still be repelled by EβF when the expression of each of three OBP genes was individually knocked down. However, the simultaneous knockdown of MperOBP3/7/9 expression significantly reduced the electrophysiological response and the repellent behaviours of M. persicae to EβF than the single OBP gene knockdown (P < 0.05). Rather than a normal saturation binding curve of individual OBP, the binding curve of MperOBP3/7/9 is bell-shaped with a higher affinity for the fluorescent probe N-phenyl-1-naphthylamine (1-NPN). The competitive binding assays confirmed that MperOBP3, MperOBP7, MperOBP9 and MperOBP3/7/9 mixture exhibited a stronger binding affinity for EβF, than for sex pheromones and plant volatiles with a dissociation constant of 2.5 μM, 1.1 μM, 3.9 μM and 1.0 μM, respectively. The competitive binding curve of MperOBP3/7/9 mixture to EβF is shallow without bottom plateau, suggesting a conformational change and a rapid dissociation after the displacement of all 1-NPN (in vivo after the saturation binding of all OBPs by EβF). The interaction between OBPs and formation of a heterogeneous unit may facilitate the delivery EβF to the OR at electrophysiological and behavioural levels during insect odorant signal transduction thus mediate M. persicae response to the alarm pheromone EβF.

Functional Response and Intraspecific Competition in the Fall Armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae).

Simple SummaryThe fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is endemic to the Western Hemisphere, where it is particularly damaging to corn, and has become invasive to Africa and Asia in 2016, and 2018, respectively. In January 2019, the FAW was first found in southwest China, and by September 2019 it reached almost all southern Chinese provinces. Since China is the second largest corn producer in the world, it is necessary to study the feeding behavior of the FAW to provide a valuable reference for Chinese corn production and food security. In this study, the functional response and intraspecific competition of the FAW larvae were evaluated under the laboratory conditions. Our study indicates that fifth and sixth instar larvae can cause major host plant damage. Therefore, these should be the focus of any pest management strategy. Intraspecific competition, especially cannibalism impacts the feeding patterns of the FAW larvae and thus needs close attention. Studying the functional response and intraspecific competition could bring tremendous insights into the FAW-host and the FAW-FAW interactions.Functional responses of the fall armyworm (FAW) larvae at each stage, and their intraspecific competition associated with cannibalism, provide insights into developing pest management strategies for the FAW. To help use insecticides more sparingly, the functional response and intraspecific competition of the FAW larvae were evaluated under the laboratory conditions. The results showed that all stages of the FAW larvae displayed a type II functional response to diet. Based on Holling’s disc equation, the search rate (a) and handling time (Th) of sixth instar larvae (a = 0.493; Th = 0.37 min) were the highest, and the shortest of all larval stages, respectively. Intraspecific competition curves fitted the data for fourth to sixth larval stages of the FAW, and the coefficient of intraspecific competition (m) assessed by the intraspecific competition equation were highest for fifth instar larvae (m = 0.48). The present study indicates that 5th and 6th instar larvae can cause the most plant damage (accounted for 88.9% of larval consumption), and these stages should be the focus of any pest management strategy. Intraspecific competition, especially cannibalism, impacts the feeding patterns of the FAW larvae and needs close attention. Understanding the functional response and intraspecific competition of the FAW larvae contributes greatly to practical applications of insecticides, increasing the effectiveness of chemical sprays and decreasing ecological damage.

Peak-valley time division model based on net load curve

As China has been quickly promoting its power market reform, the degree of thermal power units participating in market transaction has been gradually deepened. Aiming at different situations of load, thermal power units need to adopt bidding strategy accordingly. In power system with high proportion of renewable energy, the competition curve that thermal power units actually face is no longer total load curve. Proper division of peak-valley time intervals will guide thermal power units to adjust bidding strategy positively and effectively in the competition. A net-load-curve-based peak-valley time division model is built in this paper with the help of K-means algorithm. And then the paper contrasts and analyses the distributive characteristics of total and net load curves through a calculation example to verify the positive effect this model has on accurate bid for thermal power units.

Molecular interactions between sex hormone–binding globulin and nonsteroidal ligands that enhance androgen activity

Molecular interactions between sex hormone–binding globulin and nonsteroidal ligands that enhance androgen activity

Research on Electricity Market Transaction Model under the Background of Big Data

With the advancement of electricity market reform and the influence of new entities, electricity market transactions have formed a diversified development trend, which puts forward higher requirements for transaction technology support systems. In the trading market a few days ago, power producers participated in the bidding of electricity generation. The trading center gave the optimal trading plan and settlement price under the condition of satisfying the safety constraints of the power grid according to the published competitive load curve and the declared data of power generation companies. The commodities traded in the electricity market are electric energy and various services necessary for the realization of electric energy trading, so the trading in the electricity market is very different from the traditional generation plan. Only by establishing the bidding trading plan model of the trading center can the trading plan be carried out, thus forming the power purchase plan for the power generation company. This paper analyzes the basic sources and characteristics of big data in the power market, obtains the characteristic values of big data attributes of mutual benefit and win-win of both parties through the model, and realizes the visualization of transaction price.

Competitive balance within CONCACAF: a longitudinal and comparative descriptive review of the seasons 2002/2003–2017/2018

ABSTRACTRationale/Purpose: This article examines the trend in competitive balance and its association with end-of-year FIFA rankings among CONCACAF football associates.Design/methodology/approach: Secondary data were collected from the football domestic league tables for the seasons 2002/2003–2017/2018 of Costa Rica, Mexico, USA, Panama, Jamaica, Honduras, Trinidad and Tobago and Canada. Competitive balance was assessed using the Five-Club Concentration Ratio Index of Competitive Balance (C5ICB), Herfindahl Index of Competitive Balance (HICB) and Lorenz Seasonal Balance Curve. Linear regression modeling was used to assess the relationship between end-of-year FIFA ranking and competitive balance.Findings: The most competitive league was the USA, Honduras and Mexico, while the least competitive leagues were Trinidad and Tobago, Canada and Panama. For the 2017/2018 season within CONCACAF it was seen that the football leagues of the Jamaica, USA, Mexico and Panama were the most competitive balance leagues. The HICB and C5ICB were both significant predictors of a change in CONCACAF countries end-of-year FIFA rankings.Practical Implications: Competitive balance continues to be a vital component in assessing the viability and competitiveness of a football league which may have direct impacts on league authorities, marketing revenue streams and spectator attractions.Research Contribution: This is the first study to describe competitive balance in CONCACAF.