The hook formation mechanism in continuously cast slabs of ultra-low carbon steel was analyzed in detail through numerical calculations and experimental observations using optical microscopy,and its distribution chara...The hook formation mechanism in continuously cast slabs of ultra-low carbon steel was analyzed in detail through numerical calculations and experimental observations using optical microscopy,and its distribution characteristics were determined.Numerical simulations confirmed that the freezing–overflow mechanism is the primary cause of hook formation.They also revealed that the freezing event occurs unpredictably,while the overflow event takes place during the positive strip time.The average pitch of oscillation marks(OMs)on the slab surface was 8.693 mm,while the theoretical pitch was 8.889 mm,with a difference of approximately 2%.This discrepancy primarily results from varying degrees of overflow,which affects the morphology of the OMs and the positions of their deepest points.Notably,this result further confirmed that the freezing and overflow in the meniscus were indeed caused by the periodic oscillation of the mold.Higher superheat hindered hook formation,leading to a negative correlation between the hook depth distribution around the slab and the temperature distribution within the mold.Therefore,the depth of the corner hook was greater than that of other positions,which was caused by the intensified cooling effect of the corner.Moreover,key factors influencing hook development were analyzed,providing insights into transient fluid flow and heat transfer characteristics within the mold.Transient fluid flow and heat transfer contributed to the randomness and tendency of hook formation.This randomness was reflected in the varying angles of the hooks,whereas the tendency was evident in the negative correlation between superheat and hook length.Based on the randomness and tendency of hook formation and its profile characteristics,a new method for controlling hook depth based on“sine law”is proposed.展开更多
Objective:To confirm the therapeutic efficacy of the ginkgo biloba extract EGb761 on ischemic stroke and elucidate its underlying mechanism.Methods:Male Sprague-Dawley rats were divided into three groups:sham,model,an...Objective:To confirm the therapeutic efficacy of the ginkgo biloba extract EGb761 on ischemic stroke and elucidate its underlying mechanism.Methods:Male Sprague-Dawley rats were divided into three groups:sham,model,and EGb761(ginkgo biloba extract).Ischemic stroke was then simulated in rats via embolic middle cerebral artery occlusion surgery,with the extract administered half an hour before surgery.Neurological deficit scores,infarct volume,cerebral edema rate,and inflammatory factors served as the primary metrics for drug efficacy.Serum metabolites were analyzed using 1H-nuclear magnetic resonance to elucidate the operative mechanism.Results:Treatment with the ginkgo biloba extract EGb761 significantly ameliorated the neurological deficit scores(P=.0343),diminished the cerebral infarct volume(P=.0001)and cerebral edema rate(P=.0030),and alleviated neuroinflammation(all P<.05)in middle cerebral artery occlusion rats.In addition,it significantly altered the contents of various metabolites,such as 2-hydroxybutyrate,isoleucine,isopropanol,isobutyric acid,N6-acetyllysine,glutamate,glutamine,methionine,and N,Ndimethylglycine(all P<.05).Enrichment analysis of the differential metabolites indicated that EGb761 may be involved in the regulation of amino acid metabolism,betaine metabolism,glucose-alanine cycle,Warburg effect,and urea cycle.Conclusion:The ginkgo biloba extract EGb761 demonstrates anti-ischemic stroke effect on ischemic stroke model rats by regulating amino acids and amino acid derivatives,such as isoleucine,N6-acetyllysine,glutamate,methionine,and N,N-dimethylglycine.展开更多
Objective:To explore the effect and mechanism of action of the Wenjing Zhitong recipe(WZR)in primary dysmenorrhea(PD)treatment.Methods:Uterine contractions were induced by estradiol benzoate and oxytocin in a PD model...Objective:To explore the effect and mechanism of action of the Wenjing Zhitong recipe(WZR)in primary dysmenorrhea(PD)treatment.Methods:Uterine contractions were induced by estradiol benzoate and oxytocin in a PD model and WZR was administrated.The rate of change in uterine contractility and the writhing test were used to evaluate the effects of WZR.The serum levels of prostaglandin F_(2a)(PGF_(2a))and prostaglandin E_2(PGE_2),and the activity of cyclooxygenase-2(COX2)were detected by enzyme-linked immunosorbent assay(ELISA).The changes in phosphor-phospholipase C(pPLC/PLC),phosphor-protein kinase C(pPKC/PKC),and connexin 43(CX43)expression were detected using immunohistochemistry and western blot.Results:WZR significantly reduced the rate of change in uterine contractility and writhing times in the PD model.WZR treatment inhibited the enzymatic activity of COX2 and reduced the levels of PGF_(2a),PGF_(2a)/PGE2and COX2 in the PD model.WZR also significantly reduced the expression of pPLC/PLC,pPKC/PKC and CX43.Targeting the inhibition of COX2 activity,caffeic acid and 1-acetyl-β-carboline were validated as the active ingredients in WZR responsible for reducing uterine contractions.Conclusion:WZR attenuated PD by inhibiting COX2 activity,downregulating PGF_(2a)/PGE_2 expression,and inhibiting the PKC signaling pathway.展开更多
Two highly emissive pyrenoviologen derivatives were synthesized and used to fabricate fluorescent sensors for detection of picric acid(PA)with good sensitivity and selectivity.The sensitivity of the sensor was attribu...Two highly emissive pyrenoviologen derivatives were synthesized and used to fabricate fluorescent sensors for detection of picric acid(PA)with good sensitivity and selectivity.The sensitivity of the sensor was attributed to the specific electrostatic association effect of the cationic pyrenoviologens to the picrate anions,which also gave the sensor special selectivity among other compounds with similar structure.The electron transfer between them was attributed to the fluorescence response.Fluorescence lifetime measurements revealed that the quenching is static in nature.The novel and efficient pyrenoviologen derivatives-based sensors offered a strategy to fabricate real-life PA sensor.展开更多
Pb(Mg_(0.5)W_(0.5))O_(3)–Pb(Ni_(1/3)Nb_(2/3))O_(3)–Pb(Zr_(0.5)Ti_(0.5))O_(3)(PNN–PMW–PZT)piezoceramics were sintered at a low temperature of 900℃by the mixed metal oxide powder solid-state reaction route.CaCO_(3)...Pb(Mg_(0.5)W_(0.5))O_(3)–Pb(Ni_(1/3)Nb_(2/3))O_(3)–Pb(Zr_(0.5)Ti_(0.5))O_(3)(PNN–PMW–PZT)piezoceramics were sintered at a low temperature of 900℃by the mixed metal oxide powder solid-state reaction route.CaCO_(3) and Li_(2)CO_(3) as sintering aids and Yb_(2)O_(3) as a dopant were added into the PNN–PMW–PZT ceramic system for low-temperature sintering and enhancement of electrical properties,respectively.The effects of different Yb_(2)O_(3) doping amounts on the microstructure,dielectric,piezoelectric and ferroelectric properties of the samples were systematically investigated.The piezoceramics doped with 0.1 mol%Yb_(2)O_(3) have optimal electrical properties(d_(33)=563 pC/N,k_(p)=0.66,ε_(r)=2728(1 kHz),tanδ=0.0176(1 kHz),and T_(C)=301℃).While the piezoceramics doped with 0.3 mol% Yb_(2)O_(3) have optimal energy conversion properties:the piezoelectric voltage coefficient g_(33)=26.7×10^(-3)Vm/N and the effective piezoelectric energy conversion coefficient d_(33)×g_(33)=14366×10^(-15)m^(2)/N.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52174306)the Fundamental Research Funds for the Central Universities(Nos.N2225023 and N2425006)the Basic Research Projects of Liaoning Provincial Department of Education(No.LJ212410148027)。
文摘The hook formation mechanism in continuously cast slabs of ultra-low carbon steel was analyzed in detail through numerical calculations and experimental observations using optical microscopy,and its distribution characteristics were determined.Numerical simulations confirmed that the freezing–overflow mechanism is the primary cause of hook formation.They also revealed that the freezing event occurs unpredictably,while the overflow event takes place during the positive strip time.The average pitch of oscillation marks(OMs)on the slab surface was 8.693 mm,while the theoretical pitch was 8.889 mm,with a difference of approximately 2%.This discrepancy primarily results from varying degrees of overflow,which affects the morphology of the OMs and the positions of their deepest points.Notably,this result further confirmed that the freezing and overflow in the meniscus were indeed caused by the periodic oscillation of the mold.Higher superheat hindered hook formation,leading to a negative correlation between the hook depth distribution around the slab and the temperature distribution within the mold.Therefore,the depth of the corner hook was greater than that of other positions,which was caused by the intensified cooling effect of the corner.Moreover,key factors influencing hook development were analyzed,providing insights into transient fluid flow and heat transfer characteristics within the mold.Transient fluid flow and heat transfer contributed to the randomness and tendency of hook formation.This randomness was reflected in the varying angles of the hooks,whereas the tendency was evident in the negative correlation between superheat and hook length.Based on the randomness and tendency of hook formation and its profile characteristics,a new method for controlling hook depth based on“sine law”is proposed.
基金supported by the Youth Science Fund Project of the National Natural Science Foundation of China(82104440).
文摘Objective:To confirm the therapeutic efficacy of the ginkgo biloba extract EGb761 on ischemic stroke and elucidate its underlying mechanism.Methods:Male Sprague-Dawley rats were divided into three groups:sham,model,and EGb761(ginkgo biloba extract).Ischemic stroke was then simulated in rats via embolic middle cerebral artery occlusion surgery,with the extract administered half an hour before surgery.Neurological deficit scores,infarct volume,cerebral edema rate,and inflammatory factors served as the primary metrics for drug efficacy.Serum metabolites were analyzed using 1H-nuclear magnetic resonance to elucidate the operative mechanism.Results:Treatment with the ginkgo biloba extract EGb761 significantly ameliorated the neurological deficit scores(P=.0343),diminished the cerebral infarct volume(P=.0001)and cerebral edema rate(P=.0030),and alleviated neuroinflammation(all P<.05)in middle cerebral artery occlusion rats.In addition,it significantly altered the contents of various metabolites,such as 2-hydroxybutyrate,isoleucine,isopropanol,isobutyric acid,N6-acetyllysine,glutamate,glutamine,methionine,and N,Ndimethylglycine(all P<.05).Enrichment analysis of the differential metabolites indicated that EGb761 may be involved in the regulation of amino acid metabolism,betaine metabolism,glucose-alanine cycle,Warburg effect,and urea cycle.Conclusion:The ginkgo biloba extract EGb761 demonstrates anti-ischemic stroke effect on ischemic stroke model rats by regulating amino acids and amino acid derivatives,such as isoleucine,N6-acetyllysine,glutamate,methionine,and N,N-dimethylglycine.
基金supported by Beijing University of Chinese Medicine(1000061224003)National Natural Science Foundation of China(81903766,81900603,82104440)。
文摘Objective:To explore the effect and mechanism of action of the Wenjing Zhitong recipe(WZR)in primary dysmenorrhea(PD)treatment.Methods:Uterine contractions were induced by estradiol benzoate and oxytocin in a PD model and WZR was administrated.The rate of change in uterine contractility and the writhing test were used to evaluate the effects of WZR.The serum levels of prostaglandin F_(2a)(PGF_(2a))and prostaglandin E_2(PGE_2),and the activity of cyclooxygenase-2(COX2)were detected by enzyme-linked immunosorbent assay(ELISA).The changes in phosphor-phospholipase C(pPLC/PLC),phosphor-protein kinase C(pPKC/PKC),and connexin 43(CX43)expression were detected using immunohistochemistry and western blot.Results:WZR significantly reduced the rate of change in uterine contractility and writhing times in the PD model.WZR treatment inhibited the enzymatic activity of COX2 and reduced the levels of PGF_(2a),PGF_(2a)/PGE2and COX2 in the PD model.WZR also significantly reduced the expression of pPLC/PLC,pPKC/PKC and CX43.Targeting the inhibition of COX2 activity,caffeic acid and 1-acetyl-β-carboline were validated as the active ingredients in WZR responsible for reducing uterine contractions.Conclusion:WZR attenuated PD by inhibiting COX2 activity,downregulating PGF_(2a)/PGE_2 expression,and inhibiting the PKC signaling pathway.
基金supported by the National Natural Science Foundation of China(Nos.21603016,21704081,51603016 and21704005)Shaanxi College Students Innovation and Entrepreneurship Training Program(No.S201910710282)
文摘Two highly emissive pyrenoviologen derivatives were synthesized and used to fabricate fluorescent sensors for detection of picric acid(PA)with good sensitivity and selectivity.The sensitivity of the sensor was attributed to the specific electrostatic association effect of the cationic pyrenoviologens to the picrate anions,which also gave the sensor special selectivity among other compounds with similar structure.The electron transfer between them was attributed to the fluorescence response.Fluorescence lifetime measurements revealed that the quenching is static in nature.The novel and efficient pyrenoviologen derivatives-based sensors offered a strategy to fabricate real-life PA sensor.
基金financially supported by the Key Research and Development Program of the Sichuan Provincial Science and Technology Plan(No.2023DYF0173)the Fundamental Research Funds for the Central Universities(Nos.20826041E4280 and 20826041F4235).
文摘Pb(Mg_(0.5)W_(0.5))O_(3)–Pb(Ni_(1/3)Nb_(2/3))O_(3)–Pb(Zr_(0.5)Ti_(0.5))O_(3)(PNN–PMW–PZT)piezoceramics were sintered at a low temperature of 900℃by the mixed metal oxide powder solid-state reaction route.CaCO_(3) and Li_(2)CO_(3) as sintering aids and Yb_(2)O_(3) as a dopant were added into the PNN–PMW–PZT ceramic system for low-temperature sintering and enhancement of electrical properties,respectively.The effects of different Yb_(2)O_(3) doping amounts on the microstructure,dielectric,piezoelectric and ferroelectric properties of the samples were systematically investigated.The piezoceramics doped with 0.1 mol%Yb_(2)O_(3) have optimal electrical properties(d_(33)=563 pC/N,k_(p)=0.66,ε_(r)=2728(1 kHz),tanδ=0.0176(1 kHz),and T_(C)=301℃).While the piezoceramics doped with 0.3 mol% Yb_(2)O_(3) have optimal energy conversion properties:the piezoelectric voltage coefficient g_(33)=26.7×10^(-3)Vm/N and the effective piezoelectric energy conversion coefficient d_(33)×g_(33)=14366×10^(-15)m^(2)/N.
