•Develops a model to predict the semi-rigid performance of branch plate-to-CHS joint.•FE model for X-type branch plate-to-CHS joints is calibrated by test results.•Simplified theoretical formula for ...axial initial rigidity of the joints is created.•Parametric study on 7 parameters is carried out and their formulas are established.•Comparison analysis results show the axial semi-rigid model has a good reliability.
This study is aimed to develop a model to accurately predict the semi-rigid performance of branch plate-to-circular hollow section (CHS) joints for tubular structures. First of all, a finite element (FE) model for cross-type transverse branch plate-to-CHS (CTTPCHS) joints is calibrated by test results. Based on the improved Menegotto-Pinto equation and the axial load-local deformation curves that are resulted from the calibrated FE model, an axial semi-rigid connection model for CTTPCHS joints is established, which has 7 parameters including the axial initial stiffness. Then, the method to obtain 7 parameters is determined, and a theoretical formula for axial initial stiffness of the joints is established based on the quarter-circular arch model. The complex expression of the formula is simplified to the product of an exponential function and a power function. In addition, a numerical parametric study on 7 parameters is carried out by the calibrated FE model. And based on the results of parametric analysis and multivariate nonlinear regression analysis, the parametric formulas for the 7 parameters are established. Finally, a comparison between the FE analysis results and the semi-rigid connection model calculation results from the parametric formulas is made, which shows the axial semi-rigid connection model a good reliability.
The mycotoxin deoxynivalenol (DON) is a food contaminant that leads to reduced feed intake and reduced BW gain, as well as organ impairment. On the other hand, antimicrobial peptides have been shown ...to have positive effects on growth performance, nutrient digestibility, and immune function. The purpose of this study was to investigate the protective effects of composite antimicrobial peptides (CAP) on piglets challenged with DON. After a 7-d adaptation period, 28 individually housed piglets (Duroc × Landrace × Large Yorkshire) weaned at 28 d of age were randomly assigned to receive 1 of 4 treatments (7 pigs/treatment): negative control, basal diet (NC), basal diet + 0.4% CAP (CAP), basal diet + 4 mg/kg DON (DON), and basal diet + 4 ppm DON + 0.4% CAP (DON + CAP). On d 15 and 30 after the initiation of treatment, blood samples were collected for the determination of blood profile. Piglets were monitored for 30 d to assess performance and then were slaughtered to obtain organs for the determination of the relative weight of organs. The results showed that dietary supplementation with DON decreased (P < 0.05) ADFI, ADG, and G:F, whereas dietary supplementation with CAP improved ADG and G:F (P < 0.05). The relative weight of the kidney and pancreas was greater and the relative weight of the spleen was lighter in the DON treatment than in the other 3 treatments (P < 0.05). There were no effects (P > 0.05) on other relative weights of viscera, except the relative weight of the gallbladder, but the diamine oxidase activity in the liver decreased in DON-treated piglets (P < 0.05). Piglets in the DON treatment had increased serum concentrations of alkaline phosphatase, alanine transaminase, and aspartate aminotransferase and a dramatic decrease in total protein (P < 0.05), whereas there were no differences (P > 0.05) between the DON + CAP treatment and the other treatments. The DON treatment decreased the numbers of red blood cells and platelets, as well as the serum catalase concentrations, and decreased the serum concentrations of H2O2, maleic dialdehyde, and nitric oxide (P < 0.05). The numbers of platelets and thrombocytocrit, as well as the serum concentrations of catalase, were greater, whereas the maleic dialdehyde concentrations were decreased, in both the CAP and DON + CAP treatments compared with the other treatments (P < 0.05). Compared with the control treatment, DON decreased peripheral lymphocyte proliferation on d 15, whereas supplementation with CAP increased it on d 15 and 30 (P < 0.05). These findings indicate that CAP could improve feed efficiency, immune function, and antioxidation capacity and alleviate organ damage, and thus, it has a protective effect in piglets challenged with DON.
Deregulation of the MYC oncogene produces Myc protein that regulates multiple aspects of cancer cell metabolism, contributing to the acquisition of building blocks essential for cancer cell growth ...and proliferation. Therefore, disabling Myc function represents an attractive therapeutic option for cancer treatment. However, pharmacological strategies capable of directly targeting Myc remain elusive. Here, we identified that 3-bromopyruvate (3-BrPA), a drug candidate that primarily inhibits glycolysis, preferentially induced massive cell death in human cancer cells overexpressing the MYC oncogene, in vitro and in vivo, without appreciable effects on those exhibiting low MYC levels. Importantly, pharmacological inhibition of glutamine metabolism synergistically potentiated the synthetic lethal targeting of MYC by 3-BrPA due in part to the metabolic disturbance caused by this combination. Mechanistically, we identified that the proton-coupled monocarboxylate transporter 1 (MCT1) and MCT2, which enable efficient 3-BrPA uptake by cancer cells, were selectively activated by Myc. Two regulatory mechanisms were involved: first, Myc directly activated MCT1 and MCT2 transcription by binding to specific recognition sites of both genes; second, Myc transcriptionally repressed miR29a and miR29c, resulting in enhanced expression of their target protein MCT1. Of note, expressions of MCT1 and MCT2 were each significantly elevated in MYCN-amplified neuroblastomas and C-MYC-overexpressing lymphomas than in tumors without MYC overexpression, correlating with poor prognosis and unfavorable patient survival. These results identify a novel mechanism by which Myc sensitizes cells to metabolic inhibitors and validate 3-BrPA as potential Myc-selective cancer therapeutics.
To help create a comfortable and healthy indoor and outdoor environment in which to live, there is a need to understand turbulent air flows within the urban environment. To this end, building on a ...previously reported method 1, we develop a fast-running Non-Intrusive Reduced Order Model (NIROM) for predicting the turbulent air flows found within an urban environment. To resolve larger scale turbulent fluctuations, we employ a Large Eddy Simulation (LES) model and solve the resulting computational model on unstructured meshes. The objective is to construct a rapid-running NIROM from these results that will have ‘similar’ dynamics to the original LES model. Based on Proper Orthogonal Decomposition (POD) and machine learning techniques, this Reduced Order Model (ROM) is six orders of magnitude faster than the high-fidelity LES model and we demonstrate how ‘similar’ it can be to the high-fidelity model by comparing statistical quantities such as the mean flows, Reynolds stresses and probability densities of the velocities. We also include validation of the high-fidelity model against data from wind tunnel experiments.
This paper represents a key step towards the use of reduced order modelling for operational purposes with the tantalising possibility of it being used in place of Gaussian plume models, and the potential for greatly improved model fidelity and confidence.
•A Non-Intrusive Reduced Order Model (NIROM) is constructed using a Gaussian Regression Process machine learning method.•NIROM is used to predict the turbulent flows found within an urban neighbourhood of the Elephant and Castle area of London.•First implementation of such a model into an advanced 3D unstructured finite element mesh fluid model (Fluidity).•The model is several orders of magnitude faster than the high-fidelity Large Eddy Simulation (LES) model.
•A first Domain Decomposition (DD) method based on nodes weighting for the NIROM.•The DD uses a weighting constraint to achieve an equal accuracy in each subdomain.•The DD minimises the dynamic ...activity between subdomains.•The accuracy of the new DD based NIROM is improved compared to NIROM.•This method is validated using a realistic turbulent flow case at LSBU.
In this paper, a new Domain Decomposition Non-Intrusive Reduced Order Model (DDNIROM) is developed for turbulent flows. The method works by partitioning the computational domain into a number of subdomains in such a way that the summation of weights associated with the finite element nodes within each subdomain is approximately equal, and the communication between subdomains is minimised. With suitably chosen weights, it is expected that there will be approximately equal accuracy associated with each subdomain. This accuracy is maximised by allowing the partitioning to occur through areas of the domain that have relatively little flow activity, which, in this case, is characterised by the pointwise maximum Reynolds stresses.
A Gaussian Process Regression (GPR) machine learning method is used to construct a set of local approximation functions (hypersurfaces) for each subdomain. Each local hypersurface represents not only the fluid dynamics over the subdomain it belongs to, but also the interactions of the flow dynamics with the surrounding subdomains. Thus, in this way, the surrounding subdomains may be viewed as providing boundary conditions for the current subdomain.
We consider a specific example of turbulent air flow within an urban neighbourhood at a test site in London and demonstrate the effectiveness of the proposed DDNIROM.
•The first EnKF based on a parameterised non-intrusive reduced order model.•First implementation of the P-NIROM-EnKF within an unstructured mesh model.•The computational cost of P-NIROM-EnKF is ...reduced by several orders of magnitude.•The new P-NIROM-EnKF method is easy to extend into more complicated applications.
This paper presents a novel Ensemble Kalman Filter (EnKF) data assimilation method based on a parameterised non-intrusive reduced order model (P-NIROM) which is independent of the original computational code. EnKF techniques involve the expensive calculations of ensembles. In this work, the recently developed P-NIROM Xiao et al. 40 is incorporated into EnKF to speed up the ensemble simulations. A reduced order flow dynamical model is generated from the solution snapshots, which are obtained from a number of the high fidelity full simulations over the specific parametric space RP. The varying parameter is the background error covariance σ ∈ RP. Using the Smolyak sparse grid method, a set of parameters in the Gaussian probability density function is selected as the training points. The proposed method uses a two-level interpolation method for constructing the P-NIROM using a Radial Basis Function (RBF) interpolation method. The first level interpolation approach is used for generating the solution snapshots and POD basis functions for any given background error covariance while the second level interpolation approach for forming a set of hyper-surfaces representing the reduced system.
The EnKF in combination with P-NIROM (P-NIROM-EnKF) has been implemented within an unstructured mesh finite element ocean model and applied to a three dimensional wind driven circulation gyre case. The numerical results show that the accuracy of ensembles and updated solutions using the P-NIROM-EnKF is maintained while the computational cost is significantly reduced by several orders of magnitude in comparison to the full-EnKF.
The AlFeCoNiCrTi high-entropy alloy (HEA) powders were prepared by high-energy ball milling. The ultrafine-grained WC-HEA and WC-Co-cemented carbides were fabricated through planetary ball milling ...and heat-pressure sintering. The microstructures and properties of the sintered alloys were compared using scanning electron microscope, X-ray diffraction, mechanical property testing and electrochemical testing. It has been shown that the AlFeCoNiCrTi HEA can be used as a binder for the ultrafine-grained WC-based cemented carbide. The WC-HEA-cemented carbide has better performances than the WC-Co-cemented carbide. The suitable contents of HEA can inhibit the WC grain growth and improve the mechanical properties and corrosion resistance of cemented carbides.
Fifty years after the introduction, rubber monoculture now covers more than 400,000 ha of previously tropical seasonal rainforest, representing 20% of the land in Xishuangbanna, southwest China. ...However, little is known about effects of this widespread rubber monoculture on soil ecosystems. Here, we used soil nematodes as indicator species to assess effects of different rubber plantation types on soil ecosystems. Four land-use types (rubber monoculture, rubber and tea mixture, rubber polyculture and natural forest) at three sites were selected to compare soil nematode communities. Nematode communities were significantly different among the four land-use types. Natural forest had highest nematode abundance and taxa richness, followed by rubber polyculture, rubber and tea mixture and rubber monoculture. Compared to natural forest, rubber monoculture after 15–20 years reduced nematode taxa richness by as much as 33%. This was accompanied by reduced soil C and N, indicating loss of soil nutrients and ecological functioning. Nematode ecological indices (H′, MI and PPI) suggested a common pattern that natural forest was the most stable and undisturbed ecosystem, followed by rubber polyculture, rubber and tea mixture and rubber monoculture. Nematode trophic groups and SI indicated that food-web structures changed from complex in natural forest to much more simple in rubber monoculture. Finally, based on our results, two protective measures have been proposed to local government and farmers for rubber plantation and management in Xishuangbanna: 1. plant various cash crops such as tea, coffee, and cocoa into rubber monocultures; 2. decrease the management intensity and adjust strategies to restore surface vegetation, and ultimately convert rubber monoculture to rubber polyculture.
•We compared soil nematode communities in different rubber plantations and natural forest.•Land-use types had significant effects on nematode communities and ecological indices.•Nematode abundance was positively correlated with litter quantity.•Nematode diversity was lower in monoculture than in other rubber plantations or natural forest.
•A biochemical-thermal-hydro-mechanical coupling model was established.•Considering skeleton deformation, two-phase flow, heat transport and degradation.•Temperature, settlement and C/L simulation ...results were consistent with the test.•The temperature was affected by oxygen diffusion and moisture content.•The settlement developed by 70% in 150 days.•The C/L decreased to 0.4 in half a year.
Ventilating solid waste landfills with an oxygen supply can effectively accelerate the degradation of waste, achieve rapid stabilization, and realize the sustainable utilization of landfills. Aiming to understand and verify the aerobic degradation process in landfills, this paper proposed a biochemical-thermal-hydro-mechanical coupling model. The model considers aerobic biochemical reactions, dissolved solute migration, heat transport, two-phase flow, and skeleton deformation. The model was verified by comparison with an in-situ experiment at Jinkou landfill. The results showed the model could accurately represent the observed degradation phenomena during the experiment. The modelling results indicated that the rate of temperature increase and peak temperature of the upper layer, which were lower than those of the middle layer, were affected by heat exchange at the landfill surface. The lowest temperatures occurred near the bottom because of high water content and low oxygen concentrations. The high temperature zone migrated out from the injection well during degradation, reflecting the degradation of degradable organic matter associated with oxygen diffusion rates and aerobic degradation reactions. The initial accumulated settlement value was fast, but slowed and finally stabilized. The surface subsidence also developed from the center around the injection well to the surrounding area, and 70% of the total subsidence occurred within 150 days. This newly developed model provides a theoretical framework for analyzing the multi-field coupling of aerobic degradation of landfilled municipal solid waste (MSW).
Heart failure with preserved ejection fraction is 1 consequence of hypertension and is caused by impaired cardiac diastolic relaxation. Nitric oxide (NO) is a known modulator of cardiac relaxation. ...Hypertension can lead to a reduction in vascular NO, in part because NO synthase (NOS) becomes uncoupled when oxidative depletion of its cofactor tetrahydrobiopterin (BH(4)) occurs. Similar events may occur in the heart that lead to uncoupled NOS and diastolic dysfunction.
In a hypertensive mouse model, diastolic dysfunction was accompanied by cardiac oxidation, a reduction in cardiac BH(4), and uncoupled NOS. Compared with sham-operated animals, male mice with unilateral nephrectomy, with subcutaneous implantation of a controlled-release deoxycorticosterone acetate pellet, and given 1% saline to drink were mildly hypertensive and had diastolic dysfunction in the absence of systolic dysfunction or cardiac hypertrophy. The hypertensive mouse hearts showed increased oxidized biopterins, NOS-dependent superoxide production, reduced NO production, and dephosphorylated phospholamban. Feeding hypertensive mice BH(4) (5 mg/d), but not treating with hydralazine or tetrahydroneopterin, improved cardiac BH(4) stores, phosphorylated phospholamban levels, and diastolic dysfunction. Isolated cardiomyocyte experiments revealed impaired relaxation that was normalized with short-term BH(4) treatment. Targeted cardiac overexpression of angiotensin-converting enzyme also resulted in cardiac oxidation, NOS uncoupling, and diastolic dysfunction in the absence of hypertension.
Cardiac oxidation, independently of vascular changes, can lead to uncoupled cardiac NOS and diastolic dysfunction. BH(4) may represent a possible treatment for diastolic dysfunction.
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