Command filtered integrated estimation guidance and control for strapdown missiles with circular field of view

In this paper,an integrated estimation guidance and control(IEGC)system is designed based on the command filtered backstepping approach for circular field-of-view(FOV)strapdown missiles.The threedimensional integrated estimation guidance and control nonlinear model with limited actuator deflection angle is established considering the seeker's FOV constraint.The boundary time-varying integral barrier Lyapunov function(IBLF)is employed in backstepping design to constrain the body line-of-sight(BLOS)in IEGC system to fit a circular FOV.Then,the nonlinear adaptive controller is designed to estimate the changing aerodynamic parameters.The generalized extended state observer(GESO)is designed to estimate the acceleration of the maneuvering targets and the unmatched time-varying disturbances for improving tracking accuracy.Furthermore,the command filters are used to solve the"differential expansion"problem during the backstepping design.The Lyapunov theory is used to prove the stability of the overall closed-loop IEGC system.Finally,the simulation results validate the integrated system's effectiveness,achieving high accuracy strikes against maneuvering targets.

The importance of laminin at the blood-brain barrier

The blood-brain barrier is a unique property of central nervous system blood vessels that protects sensitive central nervous system cells from potentially harmful blood components.The mechanistic basis of this barrier is found at multiple levels,including the adherens and tight junction proteins that tightly bind adjacent endothelial cells and the influence of neighboring pericytes,microglia,and astrocyte endfeet.In addition,extracellular matrix components of the vascular basement membrane play a critical role in establishing and maintaining blood-brain barrier integrity,not only by providing an adhesive substrate for blood-brain barrier cells to adhere to,but also by providing guidance cues that strongly influence vascular cell behavior.The extracellular matrix protein laminin is one of the most abundant components of the basement membrane,and several lines of evidence suggest that it plays a key role in directing blood-brain barrier behavior.In this review,we describe the basic structure of laminin and its receptors,the expression patterns of these molecules in central nervous system blood vessels and how they are altered in disease states,and most importantly,how genetic deletion of different laminin isoforms or their receptors reveals the contribution of these molecules to blood-brain barrier function and integrity.Finally,we discuss some of the important unanswered questions in the field and provide a“to-do”list of some of the critical outstanding experiments.

Phytogenic feed additives alleviate pathogenic Escherichia coli-induced intestinal damage through improving barrier integrity and inhibiting inflammation in weaned pigs

Background:This study was conducted to investigate the effects of each phytogenic feed additive(PFA;PFA1,bitter citrus extract;PFA2,a microencapsulated blend of thymol and carvacrol;PFA3,a mixture of bitter citrus extract,thymol,and carvacrol;PFA4,a premixture of grape seed,grape marc extract,green tea,and hops;PFA5,fenugreek seed powder)on the growth performance,nutrient digestibility,intestinal morphology,and immune response in weaned pigs infected with Escherichia coli(E.coli).Results:A total of 634-week-old weaned pigs were placed in individual metabolic cages and assigned to seven treatment groups.The seven treatments were as follows:1)NC;basal diet without E.coli challenge,2)PC;basal diet with E.coli challenge,3)T1;PC+0.04%PFA1,4)T2;PC+0.01%PFA2,5)T3;PC+0.10%PFA3,6)T4;PC+0.04%PFA4,7)T5;PC+0.10%PFA5.The experiments lasted in 21 d,including 7 d before and 14 d after the first E.coli challenge.In the E.coli challenge treatments,all pigs were orally inoculated by dividing a total of 10 mL of E.coli F18 for 3 consecutive days.The PFA-added groups significantly increased(P<0.05)average daily gain and feed efficiency and decreased(P<0.05)the fecal score at d 0 to 14 post-inoculation(PI).Tumor necrosis factorαwas significantly lower(P<0.05)in the PFA-added groups except for T1 in d 14 PI compared to the PC treatment.The T3 had a higher(P<0.05)immunoglobulin G and immunoglobulin A concentration compared to the PC treatment at d 7 PI.Also,T3 showed significantly higher(P<0.05)villus height:crypt depth and claudin 1 expression in ileal mucosa,and significantly downregulated(P<0.05)the expression of calprotectin compared to the PC treatment.Conclusions:Supplementation of PFA in weaned pigs challenged with E.coli alleviated the negative effects of E.coli and improved growth performance.Among them,the mixed additive of bitter citrus extract,thymol,and carvacrol showed the most effective results,improving immune response,intestinal morphology,and expression of tight junctions.

Observer-Based Adaptive Fuzzy Tracking Control Using Integral Barrier Lyapunov Functionals for A Nonlinear System With Full State Constraints

A new fuzzy adaptive control method is proposed for a class of strict feedback nonlinear systems with immeasurable states and full constraints.The fuzzy logic system is used to design the approximator,which deals with uncertain and continuous functions in the process of backstepping design.The use of an integral barrier Lyapunov function not only ensures that all states are within the bounds of the constraint,but also mixes the states and errors to directly constrain the state,reducing the conservativeness of the constraint satisfaction condition.Considering that the states in most nonlinear systems are immeasurable,a fuzzy adaptive states observer is constructed to estimate the unknown states.Combined with adaptive backstepping technique,an adaptive fuzzy output feedback control method is proposed.The proposed control method ensures that all signals in the closed-loop system are bounded,and that the tracking error converges to a bounded tight set without violating the full state constraint.The simulation results prove the effectiveness of the proposed control scheme.

Partially hydrolyzed guar gum attenuates non-alcoholic fatty liver disease in mice through the gut-liver axis

BACKGROUND The gut-liver axis has attracted much interest in the context of chronic liver disease pathogenesis.Prebiotics such as dietary fibers were shown to attenuate non-alcoholic fatty liver disease(NAFLD)by modulating gut microbiota.Partially hydrolyzed guar gum(PHGG),a water-soluble dietary fiber,has been reported to alleviate the symptoms of various intestinal diseases and metabolic syndromes.However,its effects on NAFLD remain to be fully elucidated.To determine whether treatment with PHGG attenuates NAFLD development in mice through the gut-liver axis.METHODS Seven-week-old male C57BL/6J mice with increased intestinal permeability were fed a control or atherogenic(Ath)diet(a mouse model of NAFLD)for 8 wk,with or without 5%PHGG.Increased intestinal permeability was induced through chronic intermittent administration of low-dose dextran sulfate sodium.Body weight,liver weight,macroscopic findings in the liver,blood biochemistry[aspartate aminotransferase(AST)and alanine aminotransferase(ALT),total cholesterol,triglyceride,free fatty acids,and glucose levels],liver histology,myeloperoxidase activity in liver tissue,mRNA expression in the liver and intestine,serum endotoxin levels in the portal vein,intestinal permeability,and microbiota and short-chain fatty acid(SCFA)profiles in the cecal samples were investigated.RESULTS Mice with increased intestinal permeability subjected to the Ath diet showed significantly increased serum AST and ALT levels,liver fat accumulation,liver inflammatory(tumor necrosis factor-αand monocyte chemotactic protein-1)and fibrogenic(collagen 1a1 andαsmooth muscle actin)marker levels,and liver myeloperoxidase activity,which were significantly attenuated by PHGG treatment.Furthermore,the Ath diet combined with increased intestinal permeability resulted in elevated portal endotoxin levels and activated toll-like receptor(TLR)4 and TLR9 expression,confirming that intestinal permeability was significantly elevated,as observed by evaluating the lumen-to-blood clearance of fluorescein isothiocyanate-conjugated dextran.PHGG treatment did not affect fatty acid metabolism in the liver.However,it decreased lipopolysaccharide signaling through the gut-liver axis.In addition,it significantly increased the abundance of cecal Bacteroides and Clostridium subcluster XIVa.Treatment with PHGG markedly increased the levels of SCFAs,particularly,butyric acid,acetic acid,propionic acid,and formic acid,in the cecal samples.CONCLUSION PHGG partially prevented NAFLD development in mice through the gut-liver axis by modulating microbiota and downstream SCFA profiles.

Safety assessment methodology for a German high-level waste repository in clay formations

In the ANSICHT project that was jointly carried out by DBE TECHNOLOGY Gmb H,BGR,and GRS g Gmb H,two generic geological site models were used to develop a first draft of a methodology to demonstrate the safety of a high-level waste(HLW) repository in argillaceous formations in Germany,taking into account the regulatory requirements.The main results of the project are characterised by the developed repository concepts adapted to the geological conditions.The specific quantifications of the integrity criteria and their exemplary application with calculational proofs were used to demonstrate the integrity of the host rocks.The development of site-specific FEP(features,events,and processes) cataloges provided a complete system description for evaluation of the repository evolution.The developed work flow of the demonstration concept illustrated the complete sequence of the safety proof in a transparent way.It shows that various steps have to be performed,possibly iteratively,to provide a successful safety proof.The results form a useful tool in the pending search for a HLW repository site,especially when providing a basis for comparing safety analyses of different sites in Germany.

Fluctuation of zonulin levels in blood vs stability of antibodies

To evaluate the measurement of zonulin level and antibodies of zonulin and other tight junction proteins in the blood of controls and celiac disease patients. METHODSThis study was conducted to assess the variability or stability of zonulin levels vs IgA and IgG antibodies against zonulin in blood samples from 18 controls at 0, 6, 24 and 30 h after blood draw. We also measured zonulin level as well as zonulin, occludin, vinculin, aquaporin 4 and glial fibrillary acidic protein antibodies in the sera of 30 patients with celiac disease and 30 controls using enzyme-linked immunosorbent assay methodology. RESULTSThe serum zonulin level in 6 out of 18 subjects was low or < 2.8 ng/mL and was very close to the detection limit of the assay. The other 12 subjects had zonulin levels of > 2.8 ng/mL and showed significant fluctuation from sample to sample. Comparatively, zonulin antibody measured in all samples was highly stable and reproducible from sample to sample. Celiac disease patients showed zonulin levels with a mean of 8.5 ng/mL compared to 3.7 ng/mL in controls (P < 0.0001). Elevation of zonulin level at 2SD above the mean was demonstrated in 37% of celiac disease patients, while antibodies against zonulin, occludin and other tight junction proteins was detected in up to 86% of patients with celiac disease. CONCLUSIONDue to its fluctuation, a single measurement of zonulin level is not recommended for assessment of intestinal barrier integrity. Measurement of IgG and IgA antibodies against zonulin, occludin, and other tight junction proteins is proposed for the evaluation of the loss of intestinal barrier integrity.

Asymmetric time-varying integral barrier Lyapunov function based adaptive optimal control for nonlinear systems with dynamic state constraints

This paper investigates the issue of adaptive optimal tracking control for nonlinear systems with dynamic state constraints.An asymmetric time-varying integral barrier Lyapunov function(ATIBLF)based integral reinforcement learning(IRL)control algorithm with an actor–critic structure is first proposed.The ATIBLF items are appropriately arranged in every step of the optimized backstepping control design to ensure that the dynamic full-state constraints are never violated.Thus,optimal virtual/actual control in every backstepping subsystem is decomposed with ATIBLF items and also with an adaptive optimized item.Meanwhile,neural networks are used to approximate the gradient value functions.According to the Lyapunov stability theorem,the boundedness of all signals of the closed-loop system is proved,and the proposed control scheme ensures that the system states are within predefined compact sets.Finally,the effectiveness of the proposed control approach is validated by simulations.

Effects of benzoic acid,Bacillus coagulans and oregano oil combined supplementation on growth performance,immune status and intestinal barrier integrity of weaned piglets

This experiment was conducted to investigate the effects of benzoic acid,Bacillus coagulans and oregano oil combined supplementation on growth performance,immune status and intestinal barrier integrity of piglets.In a 26-d experiment,25 piglets were randomly assigned to 5 treatments:1)a basal diet,negative control(NC),2)NC added with antibiotics,positive control(PC);3)NC added with benzoic acid at 3,000 g/t and Bacillus coagulans at 400 g/t(AB);4)NC added with benzoic acid at 3,000 g/t and o regano oil at 400 g/t(AO);5)NC added with 3,000 g/t benzoic acid and Bacillus coagulans at 400 g/t and oregano oil at 400 g/t(ABO);On d 27,all piglets were euthanized to obtain jejunal mucosa to measure immune status and intestinal barrier integrity.Results showed that pigs fed AB diet increased the final body weight and average daily body weight gain and decreased the ratio of feed to gain co mpared with NC group(P<0.05).Co mpared with NC group,AB,AO and ABO decreased serum tumor necrosis factor-a concentration and ABO decreased interleukin-1βconcentration in serum and jejunal mucosa(P<0.05).Compared with NC group,AB upregulated mRNA expressions of sodium-glucose cotransportel,claudin-1,occludin and mucin2 in jejunal mucosa and the populations of Bifidobacterium and Bacillus in cecal digesta(P<0.05).Compared with NC group,ABO increased jejunal mucosal occludin mRNA abundance and Bifidobacterium population in cecal digesta,and decreased Escherichia coli population in cecal digesta(P<0.05).Furthermore,AB and ABO increased Bacillus population in cecal digesta compared with PC group(P<0.05).These results indicated that dietary AB supplementation could improve growth performance and intestinal barrier integrity of piglets when fed antibiotic-free diets,which was possibly associated with the improvement of immune status and intestinal microflora.Dietary ABO supplementation is also beneficial to improve immune status and intestinal barrier integrity and micro flora of piglets.