This article deals with a class of numerical methods for retarded differential algebraic systems with time-variable delay. The methods can be viewed as a combination of Runge-Kutta methods and Lagrange interpolation. ...This article deals with a class of numerical methods for retarded differential algebraic systems with time-variable delay. The methods can be viewed as a combination of Runge-Kutta methods and Lagrange interpolation. A new convergence concept, called DA-convergence, is introduced. The DA-convergence result for the methods is derived. At the end, a numerical example is given to verify the computational effectiveness and the theoretical result.展开更多
Objective:To determine the prevalence of intestinal parasitic infections among mentally retarded residents of rehabilitation center of Bandar Abbas,Hormozgan province,southern Iran.Methods:A cross-sectional study was ...Objective:To determine the prevalence of intestinal parasitic infections among mentally retarded residents of rehabilitation center of Bandar Abbas,Hormozgan province,southern Iran.Methods:A cross-sectional study was carried out in central rehabilitation institute of Hormozgan province in summer 2010.Fecal samples of all 133 residents(72 males,61 females)aged 3-52,were collected in triplicate.Specimens were examined by direct smear,formalin-ether concentration techniques and stained by permanent Trichrome,Ziehl-Neelsen stains.Statistical analysis was conducted by SPSS 13.5.Results:Intestinal parasitic infections were seen in 48.5%(64 out of 133 subjects:53.4%in males and 46.6%in females).Strongyloides stercoralis with17.3%showed the highest incidence followed by Entamoeba coli(9.8%),Blastocystis hominis(7.5%),Giardia lamblia(2.3%),Endolimax nana(2.3%),Hymenolepis nana(0.8%),Oxyuris vermicularis(0.8%),and Chilomasix mesnili(0.8%).Double infections were found to be as:Strongyloides stercoralis+Giardia lamblia(2.3%),Entamoeba coli+Giardia lamblia(1.5%),Entamoeba coli+Blastocystis hominis(1.5%),Oxyuris vermicularis+Entamoeba coli(0.8%),Strongyloides stercoralis+Entamoeba coli(0.8%),respectively.Conclusions:Our findings reveal that strongyloidiasis is a common disease among mentally retarded population in southern Iran.展开更多
Let X be a Banach space, A ： D（A） X → X the generator of a compact C0- semigroup S（t） ： X → X, t ≥ 0, D a locally closed subset in X, and f ： （a, b） × X →X a function of Caratheodory type. The main ...Let X be a Banach space, A ： D（A） X → X the generator of a compact C0- semigroup S（t） ： X → X, t ≥ 0, D a locally closed subset in X, and f ： （a, b） × X →X a function of Caratheodory type. The main result of this paper is that a necessary and sufficient condition in order to make D a viable domain of the semilinear differential equation of retarded type u＇（t） = Au（t） ＋ f（t, u（t - q））, t ∈ [to, to ＋ T], with initial condition uto = φ ∈C（[-q, 0]; X）, is the tangency condition lim infh10 h^-1d（S（h）v（O）＋hf（t, v（-q））; D） = 0 for almost every t ∈ （a, b） and every v ∈ C（[-q, 0]; X） with v（0）, v（-q）∈ D.展开更多
Applications of differential equations with retarded argument can be encountered in the theory of automatic control, in the theory of self-oscillatory systems, in the study of problems connected with combustion in roc...Applications of differential equations with retarded argument can be encountered in the theory of automatic control, in the theory of self-oscillatory systems, in the study of problems connected with combustion in rocket engines, in a number of problems in economics, biophysics. The problems in this areas can be solved reducing differential equations with retarded argument. In this work an important inequality for second order differential equation with retarded argument is obtained.展开更多
Sufficient conditions for the stability with respect to part of the functional differential equation variables are given. These conditions utilize Lyapunov functions to determine the uniform stability and uniform asym...Sufficient conditions for the stability with respect to part of the functional differential equation variables are given. These conditions utilize Lyapunov functions to determine the uniform stability and uniform asymptotic stability of functional differential equations. These conditions for the partial stability develop the Razumikhin theorems on uniform stability and uniform asymptotic stability of functional differential equations. An example is presented which demonstrates these results and gives insight into the new stability conditions.展开更多
[ Objective] This experiment was conducted to compare the activity difference of digestive enzymes in Japanese eels Anguilla japonics and growth retarded eels under different reaction temperature. [Method] Both 20 nor...[ Objective] This experiment was conducted to compare the activity difference of digestive enzymes in Japanese eels Anguilla japonics and growth retarded eels under different reaction temperature. [Method] Both 20 normal Japanese eels （Weight from 126.4 to 140.2 g per eel） and 20 growth retarded eels （Weight from 3.5 to 8.6 g per eel） were selected, then, the protease, amylase, lipase activities in hepatopancreas, intestine and stomach under the reaction temperature 5, 10, 15, 25, 30, 35, 40, 45 and 55℃ were measured. [ Result] The protease activities in hepatopancreas, intestine and stomach all reached the highest value for both normal eels and growth retarded eels, and the order of protease activities was intestine 〉 stomach 〉 hepatopancreas except the protease activities of growth retarded eels at the temperature of 5, 15, 55℃ The protease activities in hepatopancreas, intestine and stomach of growth retarded eels were 29.5%, 15.7% and 25.2% of those of normal eels（ P 〈0. 05）. The amylase activities of both normal and growth retarded eels reached the highest value at the temperature of 30 ~C. The amylase activity or- der of normal eels was hepatopancreas 〉 intestine 〉 stomach expect the amylase activity at the temperature of 5 ~C, while the amylase activity order of growth retarded eels is intestine 〉 hepatopancreas 〉 stomach. The amylase activities in hepatopancreas, intestine and stomach of growth retarded eels were 42.4%, 73.7% and 43.8% of those of normal eels （ P 〈 0.05）. The lipase activities of both normal and growth retarded eels reached the highest value at the temperature of 35 ~C. The lipase activity order of normal eels was hepatopancreas 〉 stomach 〉 intestine, while the lipase activity order of growth retarded eels was hepatopancreas 〉 intestine 〉 stomach expect the lipase activity at the temperature of 35 ~C. The lipase activities in hepatopancreas, intestine and stomach of growth retarded eels were 41.5%, 45.6% and 23.2% of those of normal eels（ P 〈0.05）. [ Conclusion] The protease, amylase, lipase activities in hepatopancreas, intestine and stomach of growth retarded Japanese eels were significantly lower than those of normal Japanese eels, therefore, its growth was affected directly.展开更多
This paper aims to investigate the retarded Liénard-type equation+f 1(x)+f 2(x)(t-τ)+f 3(x)2+φ(x)+g(x(t-τ))=0,where τ is a nonnegative constant, f 1,f 2,f 3,φ and g are continuous functions on R. Using Liapu...This paper aims to investigate the retarded Liénard-type equation+f 1(x)+f 2(x)(t-τ)+f 3(x)2+φ(x)+g(x(t-τ))=0,where τ is a nonnegative constant, f 1,f 2,f 3,φ and g are continuous functions on R. Using Liapunov functional method, we establish a sufficient condition on the stability and boundedness of the solutions of above equation. This will generalize the main results of reference [2].展开更多
In this paper, approximate controllability of fractional order retarded semilinear systems is studied when the nonlinear term satisfies the newly formulated bounded integral contractor-type conditions. We have shown t...In this paper, approximate controllability of fractional order retarded semilinear systems is studied when the nonlinear term satisfies the newly formulated bounded integral contractor-type conditions. We have shown the existence and uniqueness of the mild solution for the fractional order retarded semilinear systems using an iterative procedure approach. Finally, we obtain the approximate controllability results of the system under simple condition.展开更多
In this paper, we consider the following second order retarded differential equations x″(t)+cx′(t)=qx(t-σ)-lx(t-δ) (1) x″(t)+p(t)x(t-τ)=0 (2) We give some sufficient conditions for the oscillation of all solutio...In this paper, we consider the following second order retarded differential equations x″(t)+cx′(t)=qx(t-σ)-lx(t-δ) (1) x″(t)+p(t)x(t-τ)=0 (2) We give some sufficient conditions for the oscillation of all solutions of Eq. (1) in the case where q, ι, σ, δ are positive numbers and c is a real number. And also, we study the asymptotic behavior of the nonoscillatory solutions. If necessary, we give some examples to illustrate our results. At last, we study Eq. (2) with some conditions on p(t).展开更多
In this paper, we discuss the driving-response synchronization problem for two memristive neural networks with retarded and advanced arguments under the condition of additional noise. The control law is related to the...In this paper, we discuss the driving-response synchronization problem for two memristive neural networks with retarded and advanced arguments under the condition of additional noise. The control law is related to the linear time-delay feedback term, and the discontinuous feedback term. Moreover, the random different equation is used to prove the stability of this theory. At the end, the simulation results verify the correctness of the theoretical results.展开更多
Chinese is not only a basic subject in ordinary schools, but also an important subject in schools for the mentally retarded. It determines the learning ability of students with intellectual disabilities to learn other...Chinese is not only a basic subject in ordinary schools, but also an important subject in schools for the mentally retarded. It determines the learning ability of students with intellectual disabilities to learn other subjects, and it is also a necessary tool to help students with intellectual disabilities better integrate into and adapt to society in the future. When organizing and carrying out the Chinese teaching for the mentally retarded, teachers should not only pay attention to the explanation of the Chinese knowledge of the mentally retarded students, but also be good at combining it with the life-oriented content, making the Chinese teaching more practical and closer to the actual life of the students while optimizing the teaching methods, ensuring the quality of classroom teaching while truly practicing the concept of "life education" and helping the mentally retarded students to grow up in an all-round way.展开更多
Mentally retarded children are the most disadvan- taged among disabled children. Since the reform and opening up, with sup- port from the Communist Party of China, the government and the public, the legitimate rights ...Mentally retarded children are the most disadvan- taged among disabled children. Since the reform and opening up, with sup- port from the Communist Party of China, the government and the public, the legitimate rights and interests of mentally retarded children have greatly improved. But problems in this respect remain serious, and vari- ous levels of government, relevant departments and the public should attach much importance to these problems. This paper, taking a reha- bilitation center in Liaoning Province for mentally retarded children as a single case, studies the protection of these children＇s lawful rights and in- terests in a systematic manner.展开更多
A sufficient condition is obtained for every solution of the nonlinear retarded differential equationx'(t) +f(t,x(t-τ)) =0to tend to zero as t→∞ , which extends and improves the corresponding results obtained b...A sufficient condition is obtained for every solution of the nonlinear retarded differential equationx'(t) +f(t,x(t-τ)) =0to tend to zero as t→∞ , which extends and improves the corresponding results obtained by Ladas, Sficas and Gopalsamy.展开更多
Background: The focus of recent research has been directed toward the probiotic potential of Bacillus amyloliquefaciens(BA) on the gut health of animals. However, little is known about BA's effects on piglets with...Background: The focus of recent research has been directed toward the probiotic potential of Bacillus amyloliquefaciens(BA) on the gut health of animals. However, little is known about BA's effects on piglets with intra-uterine growth retardation(IUGR). Therefore, this study investigated the effects of BA supplementation on the growth performance,intestinal morphology, inflammatory response, and microbiota of IUGR piglets.Methods: Eighteen litters of newborn piglets were selected at birth, with one normal birth weight(NBW) and two IUGR piglets in each litter(i.e., 18 NBW and 36 IUGR piglets in total). At weaning, the NBW piglet and one of the IUGR piglets were assigned to groups fed a control diet(i.e., the NBW-CON and IUGR-CON groups). The other IUGR piglet was assigned to a group fed the control diet supplemented with 2.0 g BA per kg of diet(i.e., IUGR-BA group). The piglets were thus distributed across three groups for a four-week period.Results: IUGR reduced the growth performance of the IUGR-CON piglets compared with the NBW-CON piglets. It was also associated with decreased vil us sizes, increased apoptosis rates, reduced goblet cel numbers, and an imbalance between pro-and anti-inflammatory cytokines in the smal intestine. Supplementation with BA improved the average daily weight gain and the feed efficiency of the IUGR-BA group compared with the IUGR-CON group(P < 0.05). The IUGR-BA group exhibited increases in the ratio of jejunal vil us height to crypt depth, in ileal vil us height, and in ileal goblet cel density. They also exhibited decreases in the numbers of jejunal and ileal apoptotic cel s and ileal proliferative cel s(P < 0.05). Supplementation with BA increased interleukin 10 content, but it decreased tumor necrosis factor alpha level in the smal intestines of the IUGR-BA piglets(P < 0.05). Furthermore, compared with the IUGR-CON piglets, the IUGR-BA piglets had less Escherichia coli in their jejunal digesta, but more Lactobacil us and Bifidobacterium in their ileal digesta(P < 0.05).Conclusions: Dietary supplementation with BA improves morphology, decreases inflammatory response, and regulates microbiota in the smal intestines of IUGR piglets, which may contribute to improved growth performance during early life.展开更多
Background:Intestinal disorder is an important factor contributing to growth lag and high rates of morbidity and mortality of piglets with intrauterine growth retardation(IUGR).Resveratrol(RSV)and its derivative ptero...Background:Intestinal disorder is an important factor contributing to growth lag and high rates of morbidity and mortality of piglets with intrauterine growth retardation(IUGR).Resveratrol(RSV)and its derivative pterostilbene(PT)are natural stilbenes possessing various bioactivities,such as antioxidative and anti-inflammatory effects.This study compared the protective potential of RSV and PT on the intestinal redox status and gut microbiota in weanling piglets with IUGR.Methods:Eighteen male piglets of normal body weight(NBW)and 54 same-sex IUGR piglets were chosen according to their birth and weaning weights.The NBW piglets accepted a basal diet,while the IUGR piglets were allotted to one of three groups according to their body weight at weaning and received a basal diet,an RSV-supplemented diet(300 mg/kg),or a PT-supplemented diet(300 mg/kg),respectively.Results:Compared with IUGR piglets,both RSV and PT improved the IUGR-associated decrease in jejunal villus height and increases in plasma diamine oxidase activity and D-lactate level and jejunal apoptosis of piglets(P<0.05).Administering RSV and PT also enhanced jejunal superoxide dismutase activity and the mRNA and protein expression of superoxide dismutase 2 of IUGR piglets by promoting nuclear factor erythroid 2-related factor 2(Nrf2)nuclear translocation(P<0.05).Comparatively,PT was more effective than RSV in elevating the villus height/crypt depth ratio and occludin mRNA and protein levels in the jejunum of IUGR piglets(P<0.05).PT was also superior to RSV in increasing Nrf2 nuclear translocation and inhibiting malondialdehyde accumulation in the jejunum of IUGR piglets(P<0.05).Additionally,RSV modulated the composition of cecal microbiota of IUGR piglets,as evidenced by increasing the prevalence of the phylum Bacteroidetes and the genera Prevotella,Faecalibacterium,and Parabacteroides and inhibiting the growth of the phylum Proteobacteria and its genera Escherichia and Actinobacillus(P<0.05).Moreover,RSV significantly increased the butyrate concentration in the cecum of IUGR piglets(P<0.05).Conclusion:PT is more potent than RSV to prevent intestinal oxidative stress,while RSV has a stronger capacity to regulate gut microbiota compared to PT.展开更多
The flammability characterization and thermal composition of polymers flame retarded by decabromodiphenylethane (DBDPE) and antimony trioxide (Sb2O3) were studied by cone calorimeter and thermogravimetry (TG). The res...The flammability characterization and thermal composition of polymers flame retarded by decabromodiphenylethane (DBDPE) and antimony trioxide (Sb2O3) were studied by cone calorimeter and thermogravimetry (TG). The results show that ABS/DBDPE/Sb2O3 has the similar flammability parameters and thermal composition curves to ABS/DBDPO/Sb2O3. It suggests that DBDPE/Sb2O3 has the similar flame retardant behavior to DBDPO/Sb2O3. The heat release rate (HRR) and the effect heat combustion (EHC) curves of polymers flame retarded by DBDPE/Sb2O3 all decrease, but the mass loss rate (MLR) curve slightly increase. It shows that the decrease of HRR is not due to the increase of char formation ratio but the generation of incombustible gases. The major flame retardant mechanism of DBDPE/Sb2O3 is gas phase flame retardant mechanism. Increasing content of Sb2O3 in DBDPE/Sb2O3 can improve the flame retardant property and thermal stability of acrylonitrile butadiene styrene. Sb2O3 has a good synergistic effect with DBDPE.展开更多
The integration of high mechanical toughness,impact strength as well as excellent flame-retardant properties toward epoxy resins(EPs)have always been a dilemma.The inadequate overall performance of EPs severely restri...The integration of high mechanical toughness,impact strength as well as excellent flame-retardant properties toward epoxy resins(EPs)have always been a dilemma.The inadequate overall performance of EPs severely restricts their sustainable utilization in engineering aspects over long-term.Herein,a new bio-based agent(diglycidyl ether of magnolol phosphine oxide,referred as DGEMP)derived from magnolol(classified as lignan),extracted from natural plants Magnolia officinalis,was successfully synthesized and further employed as a flameretardant reactive additive to diglycidyl ether of bisphenol A(DGEBA).As demonstration,the composite resin,DGEBA/15DGEMP(15 wt%DGEMP),achieved an Underwriters Laboratories-94 V-0 rating with a high limiting oxygen index(LOI)value(41.5%).In cone calorimeter tests,it showed that heat release and smoke production were effectively inhibited during combustion,wherein the peak heat release rate(PHRR)value of DGEBA/15DGEMP was reduced by 50%compared to neat DGEBA.Additionally,it exhibited a superior tensile strength(82.8 MPa),toughness(5.11MJ/m^(3))and impact strength(36.5 k J/m^(2)),much higher than that of neat DGEBA(49.7 MPa,2.05 MJ/m^(3)and 20.9 k J/m^(2)).Thus,it is highly anticipated that DGEMP imparts significantly improved mechanical and fire-retarded properties to conventional EPs,which holds a great potential to address the pressing challenges in EP thermosets industry.展开更多
The effect of ammonium sulfamate （AS） content on the flame retardancy of polyamide 6 （PA6） was studied. It is found that the limiting oxygen index （LOI） of PA6 increases with the increase of AS content and the f...The effect of ammonium sulfamate （AS） content on the flame retardancy of polyamide 6 （PA6） was studied. It is found that the limiting oxygen index （LOI） of PA6 increases with the increase of AS content and the flame retardancy of PA6 is significantly improved. The morphology of the residues after combustion was examined by means of scanning electron microscopy （SEM）. SEM results show that AS facilitates the formation of the intumescent char layer with honeycomb-like structure, which inhibits the transfer of heat and mass, and thus improves the flame retardancy of PA6. The thermal degradation of AS flame retarded PA6 was studied by thermogravimetric analysis （TGA）. The Kissinger method was applied to estimate the activation energy （Ea） of the degradation. The activation energy of the thermal degradation of PA6 decreases by adding AS, indicating that AS can promote the degradation of PA6.展开更多
The use of intumescent flame retardants(IFRs)is considered an environmentally friendly and cost-effective strategy to suppress potential fire hazards from synthetic polymers.However,some conventional IFRs are neither ...The use of intumescent flame retardants(IFRs)is considered an environmentally friendly and cost-effective strategy to suppress potential fire hazards from synthetic polymers.However,some conventional IFRs are neither efficient in developing a thermally stable char layer nor reducing the release of toxic byproducts during polymer combustion.In this work,we aim to discuss the effects of zeolitic imidazolate frameworks(ZIFs)on synergistically improving the flame retardancy behaviors in polypropylene(PP)composites,including thermal degradation(evolved gas analysis),free radical reactions in the gaseous phase(in-situ chemiluminescent image analysis),and carbonaceous structure in the condensed phase(micro-morphology and composition analysis).It is found that the transition metals in ZIFs can catalytically accelerate the crosslinking reaction at a lower initial temperature and decrease the amount of hydrocarbon volatiles in the gaseous phase.Once ignited,the embedded ZIFs can firstly bridge adjacent phosphorus chains in the polymer matrix to expand crosslinking degrees and then they are anchored in the developed N-doped phospho-carbonaceous networks after pyrolysis.As a result,more compact char residue structures are observed in the condensed phase for ZIF-reinforced composites.For example,by replacing 2 wt%of IFR with ZIF-67,the peak heat release rate,peak smoke production rate,and peak CO production rate are reduced by 69%,80%,and 72%,respectively,when compared to the conventional composite.These results indicate an excellent solution to resolve inherent fire hazards associated with IFRs in polymers and achieve necessary efficiency for industrial applications.It also provides a new strategy for determining flammability characteristics and combustion mechanisms of polymer composites using in-situ chemiluminescence analysis.展开更多
文摘This article deals with a class of numerical methods for retarded differential algebraic systems with time-variable delay. The methods can be viewed as a combination of Runge-Kutta methods and Lagrange interpolation. A new convergence concept, called DA-convergence, is introduced. The DA-convergence result for the methods is derived. At the end, a numerical example is given to verify the computational effectiveness and the theoretical result.
基金supported by Research Deputy of Hormozgan University of Medical Science(grant No.90/108/1977)
文摘Objective:To determine the prevalence of intestinal parasitic infections among mentally retarded residents of rehabilitation center of Bandar Abbas,Hormozgan province,southern Iran.Methods:A cross-sectional study was carried out in central rehabilitation institute of Hormozgan province in summer 2010.Fecal samples of all 133 residents(72 males,61 females)aged 3-52,were collected in triplicate.Specimens were examined by direct smear,formalin-ether concentration techniques and stained by permanent Trichrome,Ziehl-Neelsen stains.Statistical analysis was conducted by SPSS 13.5.Results:Intestinal parasitic infections were seen in 48.5%(64 out of 133 subjects:53.4%in males and 46.6%in females).Strongyloides stercoralis with17.3%showed the highest incidence followed by Entamoeba coli(9.8%),Blastocystis hominis(7.5%),Giardia lamblia(2.3%),Endolimax nana(2.3%),Hymenolepis nana(0.8%),Oxyuris vermicularis(0.8%),and Chilomasix mesnili(0.8%).Double infections were found to be as:Strongyloides stercoralis+Giardia lamblia(2.3%),Entamoeba coli+Giardia lamblia(1.5%),Entamoeba coli+Blastocystis hominis(1.5%),Oxyuris vermicularis+Entamoeba coli(0.8%),Strongyloides stercoralis+Entamoeba coli(0.8%),respectively.Conclusions:Our findings reveal that strongyloidiasis is a common disease among mentally retarded population in southern Iran.
基金Supported by the National Natural Science Foundation of China (10571150)the Natural Science Foundation of Jiangsu Education Committee (07KJB110131)
文摘Let X be a Banach space, A ： D（A） X → X the generator of a compact C0- semigroup S（t） ： X → X, t ≥ 0, D a locally closed subset in X, and f ： （a, b） × X →X a function of Caratheodory type. The main result of this paper is that a necessary and sufficient condition in order to make D a viable domain of the semilinear differential equation of retarded type u＇（t） = Au（t） ＋ f（t, u（t - q））, t ∈ [to, to ＋ T], with initial condition uto = φ ∈C（[-q, 0]; X）, is the tangency condition lim infh10 h^-1d（S（h）v（O）＋hf（t, v（-q））; D） = 0 for almost every t ∈ （a, b） and every v ∈ C（[-q, 0]; X） with v（0）, v（-q）∈ D.
文摘Applications of differential equations with retarded argument can be encountered in the theory of automatic control, in the theory of self-oscillatory systems, in the study of problems connected with combustion in rocket engines, in a number of problems in economics, biophysics. The problems in this areas can be solved reducing differential equations with retarded argument. In this work an important inequality for second order differential equation with retarded argument is obtained.
基金Supported by the National Natural Science Foundation of China(Grant No.11171014)
文摘Sufficient conditions for the stability with respect to part of the functional differential equation variables are given. These conditions utilize Lyapunov functions to determine the uniform stability and uniform asymptotic stability of functional differential equations. These conditions for the partial stability develop the Razumikhin theorems on uniform stability and uniform asymptotic stability of functional differential equations. An example is presented which demonstrates these results and gives insight into the new stability conditions.
基金LI Shang-da Jimei University Subject construction Fund(ZC2010001)
文摘[ Objective] This experiment was conducted to compare the activity difference of digestive enzymes in Japanese eels Anguilla japonics and growth retarded eels under different reaction temperature. [Method] Both 20 normal Japanese eels （Weight from 126.4 to 140.2 g per eel） and 20 growth retarded eels （Weight from 3.5 to 8.6 g per eel） were selected, then, the protease, amylase, lipase activities in hepatopancreas, intestine and stomach under the reaction temperature 5, 10, 15, 25, 30, 35, 40, 45 and 55℃ were measured. [ Result] The protease activities in hepatopancreas, intestine and stomach all reached the highest value for both normal eels and growth retarded eels, and the order of protease activities was intestine 〉 stomach 〉 hepatopancreas except the protease activities of growth retarded eels at the temperature of 5, 15, 55℃ The protease activities in hepatopancreas, intestine and stomach of growth retarded eels were 29.5%, 15.7% and 25.2% of those of normal eels（ P 〈0. 05）. The amylase activities of both normal and growth retarded eels reached the highest value at the temperature of 30 ~C. The amylase activity or- der of normal eels was hepatopancreas 〉 intestine 〉 stomach expect the amylase activity at the temperature of 5 ~C, while the amylase activity order of growth retarded eels is intestine 〉 hepatopancreas 〉 stomach. The amylase activities in hepatopancreas, intestine and stomach of growth retarded eels were 42.4%, 73.7% and 43.8% of those of normal eels （ P 〈 0.05）. The lipase activities of both normal and growth retarded eels reached the highest value at the temperature of 35 ~C. The lipase activity order of normal eels was hepatopancreas 〉 stomach 〉 intestine, while the lipase activity order of growth retarded eels was hepatopancreas 〉 intestine 〉 stomach expect the lipase activity at the temperature of 35 ~C. The lipase activities in hepatopancreas, intestine and stomach of growth retarded eels were 41.5%, 45.6% and 23.2% of those of normal eels（ P 〈0.05）. [ Conclusion] The protease, amylase, lipase activities in hepatopancreas, intestine and stomach of growth retarded Japanese eels were significantly lower than those of normal Japanese eels, therefore, its growth was affected directly.
文摘This paper aims to investigate the retarded Liénard-type equation+f 1(x)+f 2(x)(t-τ)+f 3(x)2+φ(x)+g(x(t-τ))=0,where τ is a nonnegative constant, f 1,f 2,f 3,φ and g are continuous functions on R. Using Liapunov functional method, we establish a sufficient condition on the stability and boundedness of the solutions of above equation. This will generalize the main results of reference [2].
文摘In this paper, approximate controllability of fractional order retarded semilinear systems is studied when the nonlinear term satisfies the newly formulated bounded integral contractor-type conditions. We have shown the existence and uniqueness of the mild solution for the fractional order retarded semilinear systems using an iterative procedure approach. Finally, we obtain the approximate controllability results of the system under simple condition.
文摘In this paper, we consider the following second order retarded differential equations x″(t)+cx′(t)=qx(t-σ)-lx(t-δ) (1) x″(t)+p(t)x(t-τ)=0 (2) We give some sufficient conditions for the oscillation of all solutions of Eq. (1) in the case where q, ι, σ, δ are positive numbers and c is a real number. And also, we study the asymptotic behavior of the nonoscillatory solutions. If necessary, we give some examples to illustrate our results. At last, we study Eq. (2) with some conditions on p(t).
文摘In this paper, we discuss the driving-response synchronization problem for two memristive neural networks with retarded and advanced arguments under the condition of additional noise. The control law is related to the linear time-delay feedback term, and the discontinuous feedback term. Moreover, the random different equation is used to prove the stability of this theory. At the end, the simulation results verify the correctness of the theoretical results.
文摘Chinese is not only a basic subject in ordinary schools, but also an important subject in schools for the mentally retarded. It determines the learning ability of students with intellectual disabilities to learn other subjects, and it is also a necessary tool to help students with intellectual disabilities better integrate into and adapt to society in the future. When organizing and carrying out the Chinese teaching for the mentally retarded, teachers should not only pay attention to the explanation of the Chinese knowledge of the mentally retarded students, but also be good at combining it with the life-oriented content, making the Chinese teaching more practical and closer to the actual life of the students while optimizing the teaching methods, ensuring the quality of classroom teaching while truly practicing the concept of "life education" and helping the mentally retarded students to grow up in an all-round way.
文摘Mentally retarded children are the most disadvan- taged among disabled children. Since the reform and opening up, with sup- port from the Communist Party of China, the government and the public, the legitimate rights and interests of mentally retarded children have greatly improved. But problems in this respect remain serious, and vari- ous levels of government, relevant departments and the public should attach much importance to these problems. This paper, taking a reha- bilitation center in Liaoning Province for mentally retarded children as a single case, studies the protection of these children＇s lawful rights and in- terests in a systematic manner.
文摘A sufficient condition is obtained for every solution of the nonlinear retarded differential equationx'(t) +f(t,x(t-τ)) =0to tend to zero as t→∞ , which extends and improves the corresponding results obtained by Ladas, Sficas and Gopalsamy.
基金provided by the National Science-Technology Support Plan Projects of China(No.2013BAD10B02–03)the Phase Ⅱ Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Background: The focus of recent research has been directed toward the probiotic potential of Bacillus amyloliquefaciens(BA) on the gut health of animals. However, little is known about BA's effects on piglets with intra-uterine growth retardation(IUGR). Therefore, this study investigated the effects of BA supplementation on the growth performance,intestinal morphology, inflammatory response, and microbiota of IUGR piglets.Methods: Eighteen litters of newborn piglets were selected at birth, with one normal birth weight(NBW) and two IUGR piglets in each litter(i.e., 18 NBW and 36 IUGR piglets in total). At weaning, the NBW piglet and one of the IUGR piglets were assigned to groups fed a control diet(i.e., the NBW-CON and IUGR-CON groups). The other IUGR piglet was assigned to a group fed the control diet supplemented with 2.0 g BA per kg of diet(i.e., IUGR-BA group). The piglets were thus distributed across three groups for a four-week period.Results: IUGR reduced the growth performance of the IUGR-CON piglets compared with the NBW-CON piglets. It was also associated with decreased vil us sizes, increased apoptosis rates, reduced goblet cel numbers, and an imbalance between pro-and anti-inflammatory cytokines in the smal intestine. Supplementation with BA improved the average daily weight gain and the feed efficiency of the IUGR-BA group compared with the IUGR-CON group(P < 0.05). The IUGR-BA group exhibited increases in the ratio of jejunal vil us height to crypt depth, in ileal vil us height, and in ileal goblet cel density. They also exhibited decreases in the numbers of jejunal and ileal apoptotic cel s and ileal proliferative cel s(P < 0.05). Supplementation with BA increased interleukin 10 content, but it decreased tumor necrosis factor alpha level in the smal intestines of the IUGR-BA piglets(P < 0.05). Furthermore, compared with the IUGR-CON piglets, the IUGR-BA piglets had less Escherichia coli in their jejunal digesta, but more Lactobacil us and Bifidobacterium in their ileal digesta(P < 0.05).Conclusions: Dietary supplementation with BA improves morphology, decreases inflammatory response, and regulates microbiota in the smal intestines of IUGR piglets, which may contribute to improved growth performance during early life.
基金supported by the National Natural Science Foundation of China(Nos.31802094,31772634)the Natural Science Foundation of Jiangsu Province(No.BK20180531)+1 种基金the Postdoctoral Research Foundation of China(Nos.2018 M632320,2019 T120436)the Open Project of Shanghai Key Laboratory of Veterinary Biotechnology(No.klab201710).
文摘Background:Intestinal disorder is an important factor contributing to growth lag and high rates of morbidity and mortality of piglets with intrauterine growth retardation(IUGR).Resveratrol(RSV)and its derivative pterostilbene(PT)are natural stilbenes possessing various bioactivities,such as antioxidative and anti-inflammatory effects.This study compared the protective potential of RSV and PT on the intestinal redox status and gut microbiota in weanling piglets with IUGR.Methods:Eighteen male piglets of normal body weight(NBW)and 54 same-sex IUGR piglets were chosen according to their birth and weaning weights.The NBW piglets accepted a basal diet,while the IUGR piglets were allotted to one of three groups according to their body weight at weaning and received a basal diet,an RSV-supplemented diet(300 mg/kg),or a PT-supplemented diet(300 mg/kg),respectively.Results:Compared with IUGR piglets,both RSV and PT improved the IUGR-associated decrease in jejunal villus height and increases in plasma diamine oxidase activity and D-lactate level and jejunal apoptosis of piglets(P<0.05).Administering RSV and PT also enhanced jejunal superoxide dismutase activity and the mRNA and protein expression of superoxide dismutase 2 of IUGR piglets by promoting nuclear factor erythroid 2-related factor 2(Nrf2)nuclear translocation(P<0.05).Comparatively,PT was more effective than RSV in elevating the villus height/crypt depth ratio and occludin mRNA and protein levels in the jejunum of IUGR piglets(P<0.05).PT was also superior to RSV in increasing Nrf2 nuclear translocation and inhibiting malondialdehyde accumulation in the jejunum of IUGR piglets(P<0.05).Additionally,RSV modulated the composition of cecal microbiota of IUGR piglets,as evidenced by increasing the prevalence of the phylum Bacteroidetes and the genera Prevotella,Faecalibacterium,and Parabacteroides and inhibiting the growth of the phylum Proteobacteria and its genera Escherichia and Actinobacillus(P<0.05).Moreover,RSV significantly increased the butyrate concentration in the cecum of IUGR piglets(P<0.05).Conclusion:PT is more potent than RSV to prevent intestinal oxidative stress,while RSV has a stronger capacity to regulate gut microbiota compared to PT.
基金Project(20574020) supported by the National Natural Science Foundation of China
文摘The flammability characterization and thermal composition of polymers flame retarded by decabromodiphenylethane (DBDPE) and antimony trioxide (Sb2O3) were studied by cone calorimeter and thermogravimetry (TG). The results show that ABS/DBDPE/Sb2O3 has the similar flammability parameters and thermal composition curves to ABS/DBDPO/Sb2O3. It suggests that DBDPE/Sb2O3 has the similar flame retardant behavior to DBDPO/Sb2O3. The heat release rate (HRR) and the effect heat combustion (EHC) curves of polymers flame retarded by DBDPE/Sb2O3 all decrease, but the mass loss rate (MLR) curve slightly increase. It shows that the decrease of HRR is not due to the increase of char formation ratio but the generation of incombustible gases. The major flame retardant mechanism of DBDPE/Sb2O3 is gas phase flame retardant mechanism. Increasing content of Sb2O3 in DBDPE/Sb2O3 can improve the flame retardant property and thermal stability of acrylonitrile butadiene styrene. Sb2O3 has a good synergistic effect with DBDPE.
基金Anhui Provincial Natural Science Foundation for Distinguished Young Scholar(No.2008085J26)Natural Science Foundation in University of Anhui Province(Nos.KJ2021ZD0119 and 2022AH040251)+3 种基金China Scholarship Council(No.202008340021)Start-up Fund for Distinguished Scholars in Hefei University(No.20RC37)Anhui Provincial Natural Science Foundation(No.2108085QB47)Research Grants Council of the Hong Kong Special Administrative Region(No.City U 11208617)。
文摘The integration of high mechanical toughness,impact strength as well as excellent flame-retardant properties toward epoxy resins(EPs)have always been a dilemma.The inadequate overall performance of EPs severely restricts their sustainable utilization in engineering aspects over long-term.Herein,a new bio-based agent(diglycidyl ether of magnolol phosphine oxide,referred as DGEMP)derived from magnolol(classified as lignan),extracted from natural plants Magnolia officinalis,was successfully synthesized and further employed as a flameretardant reactive additive to diglycidyl ether of bisphenol A(DGEBA).As demonstration,the composite resin,DGEBA/15DGEMP(15 wt%DGEMP),achieved an Underwriters Laboratories-94 V-0 rating with a high limiting oxygen index(LOI)value(41.5%).In cone calorimeter tests,it showed that heat release and smoke production were effectively inhibited during combustion,wherein the peak heat release rate(PHRR)value of DGEBA/15DGEMP was reduced by 50%compared to neat DGEBA.Additionally,it exhibited a superior tensile strength(82.8 MPa),toughness(5.11MJ/m^(3))and impact strength(36.5 k J/m^(2)),much higher than that of neat DGEBA(49.7 MPa,2.05 MJ/m^(3)and 20.9 k J/m^(2)).Thus,it is highly anticipated that DGEMP imparts significantly improved mechanical and fire-retarded properties to conventional EPs,which holds a great potential to address the pressing challenges in EP thermosets industry.
基金supported by Science and Technology Department of Zhejiang Province(No.2009C11127).
文摘The effect of ammonium sulfamate （AS） content on the flame retardancy of polyamide 6 （PA6） was studied. It is found that the limiting oxygen index （LOI） of PA6 increases with the increase of AS content and the flame retardancy of PA6 is significantly improved. The morphology of the residues after combustion was examined by means of scanning electron microscopy （SEM）. SEM results show that AS facilitates the formation of the intumescent char layer with honeycomb-like structure, which inhibits the transfer of heat and mass, and thus improves the flame retardancy of PA6. The thermal degradation of AS flame retarded PA6 was studied by thermogravimetric analysis （TGA）. The Kissinger method was applied to estimate the activation energy （Ea） of the degradation. The activation energy of the thermal degradation of PA6 decreases by adding AS, indicating that AS can promote the degradation of PA6.
文摘The use of intumescent flame retardants(IFRs)is considered an environmentally friendly and cost-effective strategy to suppress potential fire hazards from synthetic polymers.However,some conventional IFRs are neither efficient in developing a thermally stable char layer nor reducing the release of toxic byproducts during polymer combustion.In this work,we aim to discuss the effects of zeolitic imidazolate frameworks(ZIFs)on synergistically improving the flame retardancy behaviors in polypropylene(PP)composites,including thermal degradation(evolved gas analysis),free radical reactions in the gaseous phase(in-situ chemiluminescent image analysis),and carbonaceous structure in the condensed phase(micro-morphology and composition analysis).It is found that the transition metals in ZIFs can catalytically accelerate the crosslinking reaction at a lower initial temperature and decrease the amount of hydrocarbon volatiles in the gaseous phase.Once ignited,the embedded ZIFs can firstly bridge adjacent phosphorus chains in the polymer matrix to expand crosslinking degrees and then they are anchored in the developed N-doped phospho-carbonaceous networks after pyrolysis.As a result,more compact char residue structures are observed in the condensed phase for ZIF-reinforced composites.For example,by replacing 2 wt%of IFR with ZIF-67,the peak heat release rate,peak smoke production rate,and peak CO production rate are reduced by 69%,80%,and 72%,respectively,when compared to the conventional composite.These results indicate an excellent solution to resolve inherent fire hazards associated with IFRs in polymers and achieve necessary efficiency for industrial applications.It also provides a new strategy for determining flammability characteristics and combustion mechanisms of polymer composites using in-situ chemiluminescence analysis.
