Two new compounds,badounoids A(1)and B(2),together with 13 known norsesquiterpenes,were isolated from the leaves of Croton tiglium L.The structures of the new compounds were established by means of spectroscopic metho...Two new compounds,badounoids A(1)and B(2),together with 13 known norsesquiterpenes,were isolated from the leaves of Croton tiglium L.The structures of the new compounds were established by means of spectroscopic methods.The absolute configuration of badounoid B was determined by single-crystal X-ray diffraction analysis.All the known compounds were isolated from Croton plants for the first time which added a new chemical facet for this genus.The selected compounds were evaluated for their cytostatic activity against several cancer cell lines.None of them was found to be active.展开更多
A Ti＋Nb bearing ultra-low carbon bake hardening sheet steel hot-rolled in the conventional austenite region and in the ferrite region with lubrication was experimentally studied. Subsequent cold rolling and continuou...A Ti＋Nb bearing ultra-low carbon bake hardening sheet steel hot-rolled in the conventional austenite region and in the ferrite region with lubrication was experimentally studied. Subsequent cold rolling and continuous annealing processes were also conducted. The results show that microstructures of ultra-low carbon bake hardening hot strips at room temperature are basically irregular polygonal ferrites. The yield strength, ultimate tensile strength, n value, and r value of the No.2 specimen hot-rolled in the ferrite region with lubrication are 243 MPa, 364 MPa, 0.29, and 1.74, respectively, which are similar to those of the No.1 specimen hot-roiled in the conventional austenite region. The elongation rate and bake hardening value of No.2 specimen are 51% and 49.4 MPa, respectively, which are greater than those of No. 1 specimen. The No.2 specimen hot-rolled in the ferrite region with lubrication exhibits good mechanical properties and relatively excellent baking hardening performance. Therefore, the hot rolling experiment of Ti＋Nb bearing ultra-low carbon bake hardening steel in the ferrite region with lubrication is feasible and can be considered in the future industrial trial production.展开更多
We have prepared polyion complex （PIC） hydrogel consisting of poly（3-（methacryloylami no）propyl-trimethylamonium chloride） and poly（sodium p-styrenesulfonate） polyelectrolytes via a two-step polymerization pro...We have prepared polyion complex （PIC） hydrogel consisting of poly（3-（methacryloylami no）propyl-trimethylamonium chloride） and poly（sodium p-styrenesulfonate） polyelectrolytes via a two-step polymerization procedure and have investigated specific ion effects on the self- healing of the PIC hydrogel. Our study demonstrates that the mechanical properties of the PIC hydrogel are strongly dependent on the type of the ions doped in the hydrogel. The ion-specific effects can be used to modulate the self-healing efficiency of the PIC hydrogel. As the doped anions change from kosmotrops to chaotropes, the self-healing efficiency of the PIC hydrogel increases. A more chaotropic anion has a stronger ability to break the ionic bonds formed within the hydrogel, leading to a higher efficiency during the healing.展开更多
OBJECTIVE To demonstrate the long-or short-term impacts of neonatal Pxr(pregnane X receptor) agonists exposureon DMEs(drug metabolism enzymes) expression in adulthood.METHODS C57 BL/6 mice(day 5,postnatal) were inject...OBJECTIVE To demonstrate the long-or short-term impacts of neonatal Pxr(pregnane X receptor) agonists exposureon DMEs(drug metabolism enzymes) expression in adulthood.METHODS C57 BL/6 mice(day 5,postnatal) were injected with different doses(0,50,100,150,200 mg·kg^(-1) ·d^(-1),constitutive 4 d) of PCN(pregnenolone-16 a-carbonitrile).Mice at different ages(day 5,10,15,25,postna.tal) were administrated with 200 mg·kg^(-1)·d^(-1) PCN in constitutive 4 d.All mice were sacrificed at day 60 after birth.Liver samples were collected for detecting the expression of Pxr target genes.RESULTS Compared with vehicle group,the significant inductions of Cyp2 b10,Cyp3a11 and Pxrwere observed in high dose groups(150,200 mg·kg^(-1) ·d^(-1),5-8 d after birth) both in male and female mice(n=4-9/group,P<0.05).Furthermore,high dose groups(200 mg·kg^(-1)·d^(-1),5-8 d after birth) were found to have higher mRNA expression levels of Cyp2a4,Ugt1a1,Abcc4,and Oatpla4 in female mice,while Papss2 in male mice compared with vehicle groups(n= 4-9/group,P<0.05).Interestingly,a decreased mRNA expression of Sult2a1 was identified in 200(5-8 d) groups(n=4-9/group,P<0.05).Consistent with these results,the protein expression of Cyp3a11 was only increased in 200(5-8 d) groups compared with the vehicle groups(n=3/group,P<0.05).Importantly,the persistent impacts on DMEs only occurred in day 5 and day 25 treatment groups,not day 10 and day 15 groups(n=4/group).CONCLUSION Neonatal Pxr activation has a long-term effect on the expression of DMEs in C57BL/6 mice.Dose and treatment exposure time are two key factors involved in this permanent alteration procedure.展开更多
OBJECTIVE To explore the effects of perinatal inflammation on the expression of proin.flammatory cytokines and DMEs(drug metabolism enzymes) in offspring mice.METHODS C57 BL/6 maternal mice were administrated with sin...OBJECTIVE To explore the effects of perinatal inflammation on the expression of proin.flammatory cytokines and DMEs(drug metabolism enzymes) in offspring mice.METHODS C57 BL/6 maternal mice were administrated with single dose 100 μg·kg^(-1) LPS(lipopolysaccharide) or saline(vehicle)during gestation(day 10 after fertilization).Offspring mice were sacrificed at 30 d after birth and liver samples were collected.Real-time PCR was adopted to test the mRNA expression of proinflammatory cytokines(Nrlp3 and IL-1β),nuclear receptors(Pxr and Car),and DMEs(Cyp3a11,2b10,1a2,and Ugt1a1).RESULTS Gender different expression of candidate genes was observed.The expression of Car,in the maternal injection of LPS groups,was significantly decreased in both female and male offspring(n=3-8/group,P<0.01).Concomitantly,a significantly lower expression of Cyp3a11 was found in both female and male offspring(P<0.01,P<0.05,respectively).Furthermore,the expression of Ugt1a1 was reduced in male offspring following maternal administration of LPS(P<0.01).In male offspring,Nrlp3 expression was specially decreased(P<0.05).Interestingly,there was an approximately 66% reduction in mRNA level of Cyp1a2 in female offspring(P<0.01),while in male offspring Cyp1a2 expression showed an increased trend(P>0.05) compared with vehicle group.The expression of Pxr,Cyp2b10,and IL-1β was no difference between LPS treatment group and vehicle group(P>0.05).CONCLUSION Maternal LPS administration affects the expression of proinflammatory cytokines,nuclear receptors and DMEs in mouse offspring.展开更多
The effect of salt concentration on layer-by-layer deposition of poly（sodium 4-styrene sulfonate） （PSSS）/poly（vinylbenzyl trimethylammonium chloride） （PVTC） was investigated by use of quartz crystal microbalan...The effect of salt concentration on layer-by-layer deposition of poly（sodium 4-styrene sulfonate） （PSSS）/poly（vinylbenzyl trimethylammonium chloride） （PVTC） was investigated by use of quartz crystal microbalance with dissipation （QCM-D）. The changes in frequency and dissipation demonstrate that the addition of NaC1 leads the thickness of PSSS/PVTC multilayer to increase. The deposition of PSSS/PVTC is dominated by surface charge overcompensation level at lower salt concentrations. However, it is mainly determined by the interpenetration of polyelectrolytes at a higher salt concentration, as reflected in the oscillation of dissipation change.展开更多
The counterion-mediated hydrogen bonding(CMHB)is related to the hydrogen bonding between bound counterions and polyelectrolyte chains in polyelectrolyte systems,where the counterions can both electrostatically bind to...The counterion-mediated hydrogen bonding(CMHB)is related to the hydrogen bonding between bound counterions and polyelectrolyte chains in polyelectrolyte systems,where the counterions can both electrostatically bind to the charged groups of polyelectrolyte chains and act as hydrogen bond donors or acceptors to form hydrogen bonds with the hydrogen bond sites associated with polyelectrolyte chains simultaneously.A large number of literatures illustrate that strong polyelectrolytes(SPs)are insensitive to pH,which severely limmits the applications of SPs as smart materials.However,our studies have demonstrated that the CMHB makes SPs pH-responsive.This perspective discusses the mechanism of pH responsiveness of SPs and the pH-tunable properties of SPs,based on the pH-controlled CMHB effect.The future research directions on the pH responsiveness of SPs are also discussed here.It is anticipated that the study of the pH responsiveness of SPs not only will provide a new understanding of the fundamental properties of SPs,but also will greatly expand the applications of SPs in the field of smart materials.展开更多
Soil environment on earth contains a variety of ions,which are expected to play a vital role in the biodegradation of plastics discarded in the environment.In this work,poly(butyleneadipate-co-terephthalate)(PBAT)is e...Soil environment on earth contains a variety of ions,which are expected to play a vital role in the biodegradation of plastics discarded in the environment.In this work,poly(butyleneadipate-co-terephthalate)(PBAT)is employed as a model biodegradable plastic to study the specific ion effects on the enzymatic degradation of polyester plastics.The results show that the specific ion effects on the enzymatic degradation rate of the PBAT films and on the catalytic rate constant for the enzymatic hydrolysis of the ester bonds are strongly dependent on temperature and ionic strength.Both the enzymatic degradation rate and catalytic rate constant decrease following the trends Na^(+)>K^(+)>Ca^(2+)and Cl^(-)>SO_(4)^(2-)>NO_(3)^(-)for cations and anions,respectively,indicating that the ion-specific enzymatic degradation of the PBAT films is closely correlated with the specific ion effects on enzymatic hydrolysis of the ester bonds.Our study shows that the specific ion effects on the enzyme activity can be understood by taking into account the ion-specific cation-anion interaction,ionic dispersion force,salting-out effect and salting-in effect.This study of specific ion effects on the enzymatic hydrolysis of the ester bonds and the resultant enzymatic degradation of the PBAT films would offer us a new clue to develop new biodegradable,environmentally friendly synthetic plastics.展开更多
A numerical model of an iron bath smelting reduction furnace with side-bottom combined blowing was established to study the influence of blowing arrangements on the stirring effect of the molten pool,and the accuracy ...A numerical model of an iron bath smelting reduction furnace with side-bottom combined blowing was established to study the influence of blowing arrangements on the stirring effect of the molten pool,and the accuracy of numerical simulation was verified by water model experiment.By comparing the flow field of molten pool with single nozzle,double nozzles(symmetrical and asymmetrical),and four nozzles(symmetrical and asymmetrical),the proportion of dead zone,average turbulent kinetic energy,and mixing time,the results show that asymmetrical bottom blowing is better than symmetrical bottom blowing,and the effect of double nozzles bottom blowing was better than that of four nozzles bottom blowing.The mixing effect is the worst under the condition of single nozzle.When the bottom blowing is asymmetrical with double nozzles,the mixing time is the shortest.Under the condition of double nozzles asymmetrical bottom blowing,when the insertion angle and depth of side lance are larger and deeper,the velocity streamline of molten slag layer is denser and the value is larger;meanwhile,the reflux of molten iron layer is larger,the proportion of dead zone is smaller,and the whole molten pool is fully stirred.When the insertion depth of the side lance is deeper,the gas holdup in the molten pool is greater and the stirring of the molten pool is more intense,while the insertion angle has little effect on the gas holdup.By comparing the influence of different side blowing conditions on the slag layer,it is found that the slag layer is divided into two layers by double-layer side lance,with the critical surface of the slag layer at about 200-260 mm from the bottom,and the insertion depth of the lower side lance has a greater influence on the layering of the slag.展开更多
Stainless steel （S S）/carbon steel （C S） clad plates were generated by means of the all-around weld of interface and vacuuming （AAWIV） followed by hot rolling, wherein AAWIV was utilized for controlling the inte...Stainless steel （S S）/carbon steel （C S） clad plates were generated by means of the all-around weld of interface and vacuuming （AAWIV） followed by hot rolling, wherein AAWIV was utilized for controlling the interface oxidation during hot rolling. The structure near the interface was analyzed by optical microscopy （OM）, scanning electron mi- croscopy （SEM） and transmission electron microscopy （TEM）. The mechanical properties of SS/CS clad plates were investigated by tensile and shear as well as bend tests. The SS/CS interface is relatively flat and no visible separation appears. Line scanning analysis shows that diffusion of Cr and Ni from SS to CS and C from CS to SS occurred during bonding. Higher dislocation densities are observed in both layers of parent plates adhering to the interface. The SS/ CS clad plates reveal higher yield, tensile and shear strengths. Both macroscopic delamination at the interface and fracture of base CS as well as intergranular fracture appearance of flyer plate are observed in the tensile test. The shear specimen fails in a ductile manner and the bend specimen tested shows no visible crack at the interface. Taking both interracial structure and mechanical properties into account, the SS/CS clad plates exhibit sound bonding by the process of AAWIV and hot rolling.展开更多
The corrosion behavior of the new Ni-Cr-Fe base superalloy GH984G in a synthetic coal ash and flue gas environments was studied at 700 ℃. The results showed that the corrosion rate was slow during the initial corrosi...The corrosion behavior of the new Ni-Cr-Fe base superalloy GH984G in a synthetic coal ash and flue gas environments was studied at 700 ℃. The results showed that the corrosion rate was slow during the initial corrosion stage, then followed by a stage of faster mass loss. During the corrosion test, the scale trended to spall slightly, resulting in the formation of corrosion pits on the sample surfaces. The main corrosion products were identified as NiFeCrO4 and a small amount of Cr2O3. The scale microstructure involved the presence of three corrosion layers. The outer layer contained Cr, Ni, Fe, O and a small amount of S. Many micro-cracks were detected in the Cr-rich intermediate oxide layer. The inner corrosion layer was thin and rich in S. Internal sulfidation and internal oxidation occurred in the substrate. Because of its relatively high Cr content, the GH984G superalloy exhibited a good corrosion resistance under the test conditions.展开更多
The mismatch between compute performance and I/O performance has long been a stumbling block as supercomputers evolve from petaflops to exaflops. Currently, many parallel applications are I/O intensive,and their overa...The mismatch between compute performance and I/O performance has long been a stumbling block as supercomputers evolve from petaflops to exaflops. Currently, many parallel applications are I/O intensive,and their overall running times are typically limited by I/O performance. To quantify the I/O performance bottleneck and highlight the significance of achieving scalable performance in peta/exascale supercomputing, in this paper, we introduce for the first time a formal definition of the ‘storage wall' from the perspective of parallel application scalability. We quantify the effects of the storage bottleneck by providing a storage-bounded speedup,defining the storage wall quantitatively, presenting existence theorems for the storage wall, and classifying the system architectures depending on I/O performance variation. We analyze and extrapolate the existence of the storage wall by experiments on Tianhe-1A and case studies on Jaguar. These results provide insights on how to alleviate the storage wall bottleneck in system design and achieve hardware/software optimizations in peta/exascale supercomputing.展开更多
In this work,we demonstrate that the strength of anion specificities of thermosensitive polymers is determined by the affinity of direct anion binding to the polymers.We have prepared a series of thermosensitive stati...In this work,we demonstrate that the strength of anion specificities of thermosensitive polymers is determined by the affinity of direct anion binding to the polymers.We have prepared a series of thermosensitive statistical copolymers with distinct thermoresponsive behaviors.The anions can specifically interact with the different types of thermosensitive polymers in very different strengths.A similar strength of specific anion effects on thermoresponsive behaviors can be observed at very different salt concentrations for the different types of thermosensitive polymers.A stronger anion binding to the thermosensitive polymers gives rise to a more obvious anion specificity and vice versa.The work presented here opens up opportunities for the application of ion binding affinity to modulate the strength of ion specificities of thermosensitive polymers.展开更多
As the scale of supercomputers rapidly grows, the reliability problem dominates the system availability. Existing fault tolerance mechanisms, such as periodic checkpointing and process redundancy, cannot effectively f...As the scale of supercomputers rapidly grows, the reliability problem dominates the system availability. Existing fault tolerance mechanisms, such as periodic checkpointing and process redundancy, cannot effectively fix this problem. To address this issue, we present a new fault tolerance framework using process replication and prefetching （FTRP）, combining the benefits of proactive and reactive mechanisms. FTRP incorporates a novel cost model and a new proactive fault tolerance mechanism to improve the application execution efficiency. The novel cost model, called the ＇work-most＇ （WM） model, makes runtime decisions to adaptively choose an action from a set of fault tolerance mechanisms based on failure prediction results and application status. Similar to program locality, we observe the failure locality phenomenon in supercomputers for the first time. In the new proactive fault tolerance mechanism, process replication with process prefetching is proposed based on the failure locality, significantly avoiding losses caused by the failures regardless of whether they have been predicted. Simulations with real failure traces demonstrate that the FTRP framework outperforms existing fault tolerance mechanisms with up to 10% improvement in application efficiency for common failure prediction accuracy, and is effective for petascale systems and beyond.展开更多
The lower critical solution temperature （LCST） behavior of poly（acrylamide-co-diacetone acrylamide） （poly（AM-co-DAM）） copolymer in aqueous solutions was studied. The results demonstrate the LCST linearly decre...The lower critical solution temperature （LCST） behavior of poly（acrylamide-co-diacetone acrylamide） （poly（AM-co-DAM）） copolymer in aqueous solutions was studied. The results demonstrate the LCST linearly decreases as the molar fraction of DAM （fDAM） increases. In the range of fDAM 〈 0.36, the transmittance increases as fDAM decreases because the more hydrophilic copolymer chains can form looser aggregates with a lower refractive index. The transmittance exhibits a minimum when fDAM is less than 0.28 as the chains form micelle-like structure with a size smaller than the wavelength. The LCST decreases with the initial polymer concentration, but it levels off when the polymer concentration is high enough. Moreover, no hysteresis can be observed in the change of transmittance during the heating-cooling process because no additional hydrogen bonds are formed in the collapsed state due to the steric hindrance of the large side groups in DAM units.展开更多
The influence of hot rolling on the microstructure and subsequent mechanical characteristics of explosive-welded ferritic stainless steel （FSS）/carbon steel （CS） laminate was investigated. The results indicate tha...The influence of hot rolling on the microstructure and subsequent mechanical characteristics of explosive-welded ferritic stainless steel （FSS）/carbon steel （CS） laminate was investigated. The results indicate that by hot rolling, decarburization layer disappears and a uniform structure is gained in CS side, but ferrite grains and carbides in constituent FSS form an uneven band microstructure which is denser at superficial zone than near the interface. The transmission electron microscopy results indicate that the layers adhering to the interface show typical deformed microstructure features, i.e., stream-like strips and elongated grains in FSS plates, carbide precipitates and bended cementite fragments in CS plates; and high-density dislocations in both plates, With hot rolling, various mechanical strengths and hardness are increased, while the elongation percentage is diminished. Examination of fractographs from tensile tests reveals predominately small dimples for explosive-welded specimens, whereas both big dimples and cleavage fracture for rolled specimens. Stereomicroscopic fractographs taken on shear samples indicate that the surfaces of explosive-welded specimens exhibit uniform deformation, but uneven deformation is displayed for that of rolled specimens. These results indicate that hot rolling is beneficial to improve the strength of explosive-welded FSS/CS laminate but not good for enhancing its plasticity.展开更多
基金This work was financially supported by the Project of Natural Compound Library Construction from Chinese Academy of Sciences(KSCX2-EW-R-15).
文摘Two new compounds,badounoids A(1)and B(2),together with 13 known norsesquiterpenes,were isolated from the leaves of Croton tiglium L.The structures of the new compounds were established by means of spectroscopic methods.The absolute configuration of badounoid B was determined by single-crystal X-ray diffraction analysis.All the known compounds were isolated from Croton plants for the first time which added a new chemical facet for this genus.The selected compounds were evaluated for their cytostatic activity against several cancer cell lines.None of them was found to be active.
基金supported by the"11th five" National Science and Technology Support Project of China (No.2006BAE03A13)
文摘A Ti＋Nb bearing ultra-low carbon bake hardening sheet steel hot-rolled in the conventional austenite region and in the ferrite region with lubrication was experimentally studied. Subsequent cold rolling and continuous annealing processes were also conducted. The results show that microstructures of ultra-low carbon bake hardening hot strips at room temperature are basically irregular polygonal ferrites. The yield strength, ultimate tensile strength, n value, and r value of the No.2 specimen hot-rolled in the ferrite region with lubrication are 243 MPa, 364 MPa, 0.29, and 1.74, respectively, which are similar to those of the No.1 specimen hot-roiled in the conventional austenite region. The elongation rate and bake hardening value of No.2 specimen are 51% and 49.4 MPa, respectively, which are greater than those of No. 1 specimen. The No.2 specimen hot-rolled in the ferrite region with lubrication exhibits good mechanical properties and relatively excellent baking hardening performance. Therefore, the hot rolling experiment of Ti＋Nb bearing ultra-low carbon bake hardening steel in the ferrite region with lubrication is feasible and can be considered in the future industrial trial production.
文摘We have prepared polyion complex （PIC） hydrogel consisting of poly（3-（methacryloylami no）propyl-trimethylamonium chloride） and poly（sodium p-styrenesulfonate） polyelectrolytes via a two-step polymerization procedure and have investigated specific ion effects on the self- healing of the PIC hydrogel. Our study demonstrates that the mechanical properties of the PIC hydrogel are strongly dependent on the type of the ions doped in the hydrogel. The ion-specific effects can be used to modulate the self-healing efficiency of the PIC hydrogel. As the doped anions change from kosmotrops to chaotropes, the self-healing efficiency of the PIC hydrogel increases. A more chaotropic anion has a stronger ability to break the ionic bonds formed within the hydrogel, leading to a higher efficiency during the healing.
文摘OBJECTIVE To demonstrate the long-or short-term impacts of neonatal Pxr(pregnane X receptor) agonists exposureon DMEs(drug metabolism enzymes) expression in adulthood.METHODS C57 BL/6 mice(day 5,postnatal) were injected with different doses(0,50,100,150,200 mg·kg^(-1) ·d^(-1),constitutive 4 d) of PCN(pregnenolone-16 a-carbonitrile).Mice at different ages(day 5,10,15,25,postna.tal) were administrated with 200 mg·kg^(-1)·d^(-1) PCN in constitutive 4 d.All mice were sacrificed at day 60 after birth.Liver samples were collected for detecting the expression of Pxr target genes.RESULTS Compared with vehicle group,the significant inductions of Cyp2 b10,Cyp3a11 and Pxrwere observed in high dose groups(150,200 mg·kg^(-1) ·d^(-1),5-8 d after birth) both in male and female mice(n=4-9/group,P<0.05).Furthermore,high dose groups(200 mg·kg^(-1)·d^(-1),5-8 d after birth) were found to have higher mRNA expression levels of Cyp2a4,Ugt1a1,Abcc4,and Oatpla4 in female mice,while Papss2 in male mice compared with vehicle groups(n= 4-9/group,P<0.05).Interestingly,a decreased mRNA expression of Sult2a1 was identified in 200(5-8 d) groups(n=4-9/group,P<0.05).Consistent with these results,the protein expression of Cyp3a11 was only increased in 200(5-8 d) groups compared with the vehicle groups(n=3/group,P<0.05).Importantly,the persistent impacts on DMEs only occurred in day 5 and day 25 treatment groups,not day 10 and day 15 groups(n=4/group).CONCLUSION Neonatal Pxr activation has a long-term effect on the expression of DMEs in C57BL/6 mice.Dose and treatment exposure time are two key factors involved in this permanent alteration procedure.
文摘OBJECTIVE To explore the effects of perinatal inflammation on the expression of proin.flammatory cytokines and DMEs(drug metabolism enzymes) in offspring mice.METHODS C57 BL/6 maternal mice were administrated with single dose 100 μg·kg^(-1) LPS(lipopolysaccharide) or saline(vehicle)during gestation(day 10 after fertilization).Offspring mice were sacrificed at 30 d after birth and liver samples were collected.Real-time PCR was adopted to test the mRNA expression of proinflammatory cytokines(Nrlp3 and IL-1β),nuclear receptors(Pxr and Car),and DMEs(Cyp3a11,2b10,1a2,and Ugt1a1).RESULTS Gender different expression of candidate genes was observed.The expression of Car,in the maternal injection of LPS groups,was significantly decreased in both female and male offspring(n=3-8/group,P<0.01).Concomitantly,a significantly lower expression of Cyp3a11 was found in both female and male offspring(P<0.01,P<0.05,respectively).Furthermore,the expression of Ugt1a1 was reduced in male offspring following maternal administration of LPS(P<0.01).In male offspring,Nrlp3 expression was specially decreased(P<0.05).Interestingly,there was an approximately 66% reduction in mRNA level of Cyp1a2 in female offspring(P<0.01),while in male offspring Cyp1a2 expression showed an increased trend(P>0.05) compared with vehicle group.The expression of Pxr,Cyp2b10,and IL-1β was no difference between LPS treatment group and vehicle group(P>0.05).CONCLUSION Maternal LPS administration affects the expression of proinflammatory cytokines,nuclear receptors and DMEs in mouse offspring.
基金This work was supported by the National Natural Science Foundation of China （No.20474060）.
文摘The effect of salt concentration on layer-by-layer deposition of poly（sodium 4-styrene sulfonate） （PSSS）/poly（vinylbenzyl trimethylammonium chloride） （PVTC） was investigated by use of quartz crystal microbalance with dissipation （QCM-D）. The changes in frequency and dissipation demonstrate that the addition of NaC1 leads the thickness of PSSS/PVTC multilayer to increase. The deposition of PSSS/PVTC is dominated by surface charge overcompensation level at lower salt concentrations. However, it is mainly determined by the interpenetration of polyelectrolytes at a higher salt concentration, as reflected in the oscillation of dissipation change.
基金supported by the National Natural Science Foundation of China(Nos.22273098,52033001,22373003 and 22103002)the Fundamental Research Funds for the Central Universities(No.WK2480000007).
文摘The counterion-mediated hydrogen bonding(CMHB)is related to the hydrogen bonding between bound counterions and polyelectrolyte chains in polyelectrolyte systems,where the counterions can both electrostatically bind to the charged groups of polyelectrolyte chains and act as hydrogen bond donors or acceptors to form hydrogen bonds with the hydrogen bond sites associated with polyelectrolyte chains simultaneously.A large number of literatures illustrate that strong polyelectrolytes(SPs)are insensitive to pH,which severely limmits the applications of SPs as smart materials.However,our studies have demonstrated that the CMHB makes SPs pH-responsive.This perspective discusses the mechanism of pH responsiveness of SPs and the pH-tunable properties of SPs,based on the pH-controlled CMHB effect.The future research directions on the pH responsiveness of SPs are also discussed here.It is anticipated that the study of the pH responsiveness of SPs not only will provide a new understanding of the fundamental properties of SPs,but also will greatly expand the applications of SPs in the field of smart materials.
基金the National Natural Science Foundation of China(Nos.21873091,52033001 and 22103002)the Youth Innovation Promotion Association of CAS(No.Y201769)+1 种基金the National Synchrotron Radiation Laboratory(No.UN2018LHJJ)the Fundamental Research Funds for the Central Universities(No.WK2480000007).
文摘Soil environment on earth contains a variety of ions,which are expected to play a vital role in the biodegradation of plastics discarded in the environment.In this work,poly(butyleneadipate-co-terephthalate)(PBAT)is employed as a model biodegradable plastic to study the specific ion effects on the enzymatic degradation of polyester plastics.The results show that the specific ion effects on the enzymatic degradation rate of the PBAT films and on the catalytic rate constant for the enzymatic hydrolysis of the ester bonds are strongly dependent on temperature and ionic strength.Both the enzymatic degradation rate and catalytic rate constant decrease following the trends Na^(+)>K^(+)>Ca^(2+)and Cl^(-)>SO_(4)^(2-)>NO_(3)^(-)for cations and anions,respectively,indicating that the ion-specific enzymatic degradation of the PBAT films is closely correlated with the specific ion effects on enzymatic hydrolysis of the ester bonds.Our study shows that the specific ion effects on the enzyme activity can be understood by taking into account the ion-specific cation-anion interaction,ionic dispersion force,salting-out effect and salting-in effect.This study of specific ion effects on the enzymatic hydrolysis of the ester bonds and the resultant enzymatic degradation of the PBAT films would offer us a new clue to develop new biodegradable,environmentally friendly synthetic plastics.
基金The authors wish to express thanks to the National Natural Science Foundation of China(51904278)Shanxi Province Key R&D Program High-tech Project(201903D121093)+1 种基金Major Science and Technology Projects of Shanxi Province(20181101002)General Project of Natural Science Foundation of Shanxi Province(20210302123218)for supporting this work.
文摘A numerical model of an iron bath smelting reduction furnace with side-bottom combined blowing was established to study the influence of blowing arrangements on the stirring effect of the molten pool,and the accuracy of numerical simulation was verified by water model experiment.By comparing the flow field of molten pool with single nozzle,double nozzles(symmetrical and asymmetrical),and four nozzles(symmetrical and asymmetrical),the proportion of dead zone,average turbulent kinetic energy,and mixing time,the results show that asymmetrical bottom blowing is better than symmetrical bottom blowing,and the effect of double nozzles bottom blowing was better than that of four nozzles bottom blowing.The mixing effect is the worst under the condition of single nozzle.When the bottom blowing is asymmetrical with double nozzles,the mixing time is the shortest.Under the condition of double nozzles asymmetrical bottom blowing,when the insertion angle and depth of side lance are larger and deeper,the velocity streamline of molten slag layer is denser and the value is larger;meanwhile,the reflux of molten iron layer is larger,the proportion of dead zone is smaller,and the whole molten pool is fully stirred.When the insertion depth of the side lance is deeper,the gas holdup in the molten pool is greater and the stirring of the molten pool is more intense,while the insertion angle has little effect on the gas holdup.By comparing the influence of different side blowing conditions on the slag layer,it is found that the slag layer is divided into two layers by double-layer side lance,with the critical surface of the slag layer at about 200-260 mm from the bottom,and the insertion depth of the lower side lance has a greater influence on the layering of the slag.
基金Item Sponsored by National Key Technology Research and Development Program in 12th Five-year Plan of China(2012CB722801)National Natural Science Foundation of China(51105264)Postdoctoral Science Foundation of China(2012M520677)
文摘Stainless steel （S S）/carbon steel （C S） clad plates were generated by means of the all-around weld of interface and vacuuming （AAWIV） followed by hot rolling, wherein AAWIV was utilized for controlling the interface oxidation during hot rolling. The structure near the interface was analyzed by optical microscopy （OM）, scanning electron mi- croscopy （SEM） and transmission electron microscopy （TEM）. The mechanical properties of SS/CS clad plates were investigated by tensile and shear as well as bend tests. The SS/CS interface is relatively flat and no visible separation appears. Line scanning analysis shows that diffusion of Cr and Ni from SS to CS and C from CS to SS occurred during bonding. Higher dislocation densities are observed in both layers of parent plates adhering to the interface. The SS/ CS clad plates reveal higher yield, tensile and shear strengths. Both macroscopic delamination at the interface and fracture of base CS as well as intergranular fracture appearance of flyer plate are observed in the tensile test. The shear specimen fails in a ductile manner and the bend specimen tested shows no visible crack at the interface. Taking both interracial structure and mechanical properties into account, the SS/CS clad plates exhibit sound bonding by the process of AAWIV and hot rolling.
基金financially supported by National Science Foundation of China (Grant No. 51161022)the Science and Technology Foundation of Department of Education of Jiangxi Province, China (Nos. DB201301133, 201301050)
文摘The corrosion behavior of the new Ni-Cr-Fe base superalloy GH984G in a synthetic coal ash and flue gas environments was studied at 700 ℃. The results showed that the corrosion rate was slow during the initial corrosion stage, then followed by a stage of faster mass loss. During the corrosion test, the scale trended to spall slightly, resulting in the formation of corrosion pits on the sample surfaces. The main corrosion products were identified as NiFeCrO4 and a small amount of Cr2O3. The scale microstructure involved the presence of three corrosion layers. The outer layer contained Cr, Ni, Fe, O and a small amount of S. Many micro-cracks were detected in the Cr-rich intermediate oxide layer. The inner corrosion layer was thin and rich in S. Internal sulfidation and internal oxidation occurred in the substrate. Because of its relatively high Cr content, the GH984G superalloy exhibited a good corrosion resistance under the test conditions.
基金the National Natural Science Foundation of China(Nos.61272141 and 61120106005)the National High-Tech R&D Program(863)of China(No.2012AA01A301)
文摘The mismatch between compute performance and I/O performance has long been a stumbling block as supercomputers evolve from petaflops to exaflops. Currently, many parallel applications are I/O intensive,and their overall running times are typically limited by I/O performance. To quantify the I/O performance bottleneck and highlight the significance of achieving scalable performance in peta/exascale supercomputing, in this paper, we introduce for the first time a formal definition of the ‘storage wall' from the perspective of parallel application scalability. We quantify the effects of the storage bottleneck by providing a storage-bounded speedup,defining the storage wall quantitatively, presenting existence theorems for the storage wall, and classifying the system architectures depending on I/O performance variation. We analyze and extrapolate the existence of the storage wall by experiments on Tianhe-1A and case studies on Jaguar. These results provide insights on how to alleviate the storage wall bottleneck in system design and achieve hardware/software optimizations in peta/exascale supercomputing.
基金financially supported by the National Natural Science Foundation of China(Nos.21873091,21622405,21574121 and 52033001)the Youth Innovation Promotion Association of CAS(No.Y201769)+1 种基金the National Synchrotron Radiation Laboratory(No.UN2018LHJJ)the Fundamental Research Funds for the Central Universities(No.WK2480000007)。
文摘In this work,we demonstrate that the strength of anion specificities of thermosensitive polymers is determined by the affinity of direct anion binding to the polymers.We have prepared a series of thermosensitive statistical copolymers with distinct thermoresponsive behaviors.The anions can specifically interact with the different types of thermosensitive polymers in very different strengths.A similar strength of specific anion effects on thermoresponsive behaviors can be observed at very different salt concentrations for the different types of thermosensitive polymers.A stronger anion binding to the thermosensitive polymers gives rise to a more obvious anion specificity and vice versa.The work presented here opens up opportunities for the application of ion binding affinity to modulate the strength of ion specificities of thermosensitive polymers.
基金Project supported by the National Natural Science Foundation of China(Nos.61272141,61120106005,and 61303068)the National High-Tech R&D Program of China(No.2012AA01A301)
文摘As the scale of supercomputers rapidly grows, the reliability problem dominates the system availability. Existing fault tolerance mechanisms, such as periodic checkpointing and process redundancy, cannot effectively fix this problem. To address this issue, we present a new fault tolerance framework using process replication and prefetching （FTRP）, combining the benefits of proactive and reactive mechanisms. FTRP incorporates a novel cost model and a new proactive fault tolerance mechanism to improve the application execution efficiency. The novel cost model, called the ＇work-most＇ （WM） model, makes runtime decisions to adaptively choose an action from a set of fault tolerance mechanisms based on failure prediction results and application status. Similar to program locality, we observe the failure locality phenomenon in supercomputers for the first time. In the new proactive fault tolerance mechanism, process replication with process prefetching is proposed based on the failure locality, significantly avoiding losses caused by the failures regardless of whether they have been predicted. Simulations with real failure traces demonstrate that the FTRP framework outperforms existing fault tolerance mechanisms with up to 10% improvement in application efficiency for common failure prediction accuracy, and is effective for petascale systems and beyond.
基金financially supported by the Ministry of Science and Technology of China(No.2012CB933802)the National Natural Science Foundation of China(Nos.21004057 and 21004058)
文摘The lower critical solution temperature （LCST） behavior of poly（acrylamide-co-diacetone acrylamide） （poly（AM-co-DAM）） copolymer in aqueous solutions was studied. The results demonstrate the LCST linearly decreases as the molar fraction of DAM （fDAM） increases. In the range of fDAM 〈 0.36, the transmittance increases as fDAM decreases because the more hydrophilic copolymer chains can form looser aggregates with a lower refractive index. The transmittance exhibits a minimum when fDAM is less than 0.28 as the chains form micelle-like structure with a size smaller than the wavelength. The LCST decreases with the initial polymer concentration, but it levels off when the polymer concentration is high enough. Moreover, no hysteresis can be observed in the change of transmittance during the heating-cooling process because no additional hydrogen bonds are formed in the collapsed state due to the steric hindrance of the large side groups in DAM units.
基金This research was funded by the National Natural Science Foundation of China under Grant No. U 1510131, the Key Research and Development Program of Shanxi Province under Grant Nos. 201603D121010 and 201603D111004 and Shanxi Young Scholars Program.
文摘The influence of hot rolling on the microstructure and subsequent mechanical characteristics of explosive-welded ferritic stainless steel （FSS）/carbon steel （CS） laminate was investigated. The results indicate that by hot rolling, decarburization layer disappears and a uniform structure is gained in CS side, but ferrite grains and carbides in constituent FSS form an uneven band microstructure which is denser at superficial zone than near the interface. The transmission electron microscopy results indicate that the layers adhering to the interface show typical deformed microstructure features, i.e., stream-like strips and elongated grains in FSS plates, carbide precipitates and bended cementite fragments in CS plates; and high-density dislocations in both plates, With hot rolling, various mechanical strengths and hardness are increased, while the elongation percentage is diminished. Examination of fractographs from tensile tests reveals predominately small dimples for explosive-welded specimens, whereas both big dimples and cleavage fracture for rolled specimens. Stereomicroscopic fractographs taken on shear samples indicate that the surfaces of explosive-welded specimens exhibit uniform deformation, but uneven deformation is displayed for that of rolled specimens. These results indicate that hot rolling is beneficial to improve the strength of explosive-welded FSS/CS laminate but not good for enhancing its plasticity.
