The von Hippel-Lindau tumor suppressor protein(VHL),an E3 ubiquitin ligase,functions as a critical regulator of the oxygen-sensing pathway for targeting hypoxia-inducible factors.Recent evidence suggests that mammalia...The von Hippel-Lindau tumor suppressor protein(VHL),an E3 ubiquitin ligase,functions as a critical regulator of the oxygen-sensing pathway for targeting hypoxia-inducible factors.Recent evidence suggests that mammalian VHL may also be critical to the NF-κB signaling pathway,although the specific molecular mechanisms remain unclear.Herein,the roles of mandarin fish(Siniperca chuatsi)VHL(scVHL)in the NF-κB signaling pathway and mandarin fish ranavirus(MRV)replication were explored.The transcription of scVHL was induced by immune stimulation and MRV infection,indicating a potential role in innate immunity.Dual-luciferase reporter gene assays and reverse transcription quantitative PCR(RT-qPCR)results demonstrated that scVHL evoked and positively regulated the NF-κB signaling pathway.Treatment with NF-κB signaling pathway inhibitors indicated that the role of scVHL may be mediated through scIKKα,scIKKβ,scIκBα,or scp65.Co-immunoprecipitation(Co-IP)analysis identified scIκBαas a novel target protein of scVHL.Moreover,scVHL targeted scIκBαto catalyze the formation of K63-linked polyubiquitin chains to activate the NF-κB signaling pathway.Following MRV infection,NF-κB signaling remained activated,which,in turn,promoted MRV replication.These findings suggest that scVHL not only positively regulates NF-κB but also significantly enhances MRV replication.This study reveals a novel function of scVHL in NF-κB signaling and viral infection in fish.展开更多
AIM:To explore clinicopathologic characteristics of intrahepatic cholangiocarcinoma (ICC) in patients with positive serum a-fetoprotein (AFP). METHODS:One hundred and thirty one patients who underwent surgical dissect...AIM:To explore clinicopathologic characteristics of intrahepatic cholangiocarcinoma (ICC) in patients with positive serum a-fetoprotein (AFP). METHODS:One hundred and thirty one patients who underwent surgical dissection for pathologically confirmed ICC were divided into a positive AFP (> 20 ng/mL) group (n = 32) and a negative AFP group (n = 99), whose clinicopathologic features were analyzed and compared. RESULTS:The positive rate of HBsAg and liver cirrhosis of the positive AFP group was higher than that of the negative AFP group, while the positive rate of CA19-9 (> 37 U/mL) and the lymph node metastasis rate was lower. CONCLUSION:ICC patients with positive AFP share many clinicopathologic similarities with hepatocellular carcinoma.展开更多
Cypripedium tibeticum is a threatened orchid which efficient conservation requires knowledge of its extent and structure of genetic variation. Using two chloroplast DNA fragments(rps16 and trnL-F), we analyzed 157 ind...Cypripedium tibeticum is a threatened orchid which efficient conservation requires knowledge of its extent and structure of genetic variation. Using two chloroplast DNA fragments(rps16 and trnL-F), we analyzed 157 individuals from 9 populations representing the species range in China. Seven haplotypes were identified. C. tibeticum had high total genetic diversity(H_T=0.80) with major contribution to this diversity made by among-population component(G_ST=0.64, Ф_ST= 0.86). However, despite high population differentiation there was no clear phylogeographic structure. The populations CY and DC made the greatest contribution to the total gene diversity as well as allelic richness. The possible mechanisms and implications of these findings for conservation of the species are discussed.展开更多
Primula beesiana Forr.is an attractive wildflower endemically distributed in the wet habitats of subalpine/alpine regions of southwestern China.This study is an attempt to understand how this plant adapts to wet habit...Primula beesiana Forr.is an attractive wildflower endemically distributed in the wet habitats of subalpine/alpine regions of southwestern China.This study is an attempt to understand how this plant adapts to wet habitats and high altitudes.Specifically,we examined the effects of cold stratification,light,GA3,KNO3,and temperature on P.beesiana seed germination.KNO3 and GA3 increased germination percentage and germination rate compared to control treatments at 15/5 and 25/15℃.Untreated seeds germinated well(>80%)at higher temperatures(20,25 and 28℃),whereas at lower(5,10 and15℃)and extremely high temperatures(30 and 32℃)germination decreased significantly.However,after cold stratification(4-16 weeks),the germination percentage of P.beesiana seeds at low temperatures(5-15℃)and the germination rate at high temperatures(30℃)increased significantly,suggesting that P.beesiana has type 3 non-deep physiological dormancy.The base temperature and thermal time for germination decreased in seeds that were cold stratified for 16 weeks.Cold-stratified seeds incubated at fluctuating temperatures(especially at 15/5℃)had significantly high germination percentages and germination rates in light,but not in dark,compared to the corresponding constant temperature(10℃).Seeds had a strict light requirement at all temperatures,even after experiencing cold stratification;however,the combinations of cold stratification and fluctuating temperature increased germination when seeds were transferred from dark to light.Such dormancy/germination responses to light and temperature are likely mechanisms that ensure germination occurs only in spring and at/near the soil surface,thus avoiding seedling death by freezing,inundation and/or germination deep in the soil.展开更多
As the main link of ground engineering,crude oil gathering and transportation systems require huge energy consumption and complex structures.It is necessary to establish an energy efficiency evaluation system for crud...As the main link of ground engineering,crude oil gathering and transportation systems require huge energy consumption and complex structures.It is necessary to establish an energy efficiency evaluation system for crude oil gathering and transportation systems and identify the energy efficiency gaps.In this paper,the energy efficiency evaluation system of the crude oil gathering and transportation system in an oilfield in western China is established.Combined with the big data analysis method,the GA-BP neural network is used to establish the energy efficiency index prediction model for crude oil gathering and transportation systems.The comprehensive energy consumption,gas consumption,power consumption,energy utilization rate,heat utilization rate,and power utilization rate of crude oil gathering and transportation systems are predicted.Considering the efficiency and unit consumption index of the crude oil gathering and transportation system,the energy efficiency evaluation system of the crude oil gathering and transportation system is established based on a game theory combined weighting method and TOPSIS evaluation method,and the subjective weight is determined by the triangular fuzzy analytic hierarchy process.The entropy weight method determines the objective weight,and the combined weight of game theory combines subjectivity with objectivity to comprehensively evaluate the comprehensive energy efficiency of crude oil gathering and transportation systems and their subsystems.Finally,the weak links in energy utilization are identified,and energy conservation and consumption reduction are improved.The above research provides technical support for the green,efficient and intelligent development of crude oil gathering and transportation systems.展开更多
Insensitive energetic materials are promising in the defense weapons field.However,energetic materials still suffer from great challenges and the concern about their safety limits their utilization.In this work,insens...Insensitive energetic materials are promising in the defense weapons field.However,energetic materials still suffer from great challenges and the concern about their safety limits their utilization.In this work,insensitive energetic explosive 3,30-diamino-4,40-azoxyfurazan/hexahydro-1,3,5-trinitro-1,3,5-triazine(DAAF/RDX)microspheres were fabricated by self-assembly method.Rod-like DAAF/RDX was prepared by mechanical ball milling for comparison.DAAF/RDX composites with different mass ratios(90:10,80:20,and 70:30)were obtained.The morphologies and structures of as-obtained DAAF/RDX composites were characterized by scanning electron microscopy(SEM),powder x-ray diffraction(PXRD)and fourier transform infrared spectroscopy(FT-IR).The results showed that DAAF/RDX microspheres exhibited regular shaped microspheres with sizes from 0.5 to 1.2 mm.There was no crystal transition during the modification process.The thermal properties of as-obtained materials were then evaluated by differential scanning calorimetry(DSC)and materials studio software.DAAF/RDX microspheres showed an advanced decomposition peak temperature compared with rod-like DAAF/RDX.The binding energy and peak temperature values at zeroβ_(i)(T_(P0))of DAAF/RDX(90:10)increased by 36.77 kJ/mol,1.6℃,and 58.11 kJ/mol,12.3℃compared to DAAF/RDX(80:20)and DAAF/RDX(70:30),indicating the better thermal stability of DAAF/RDX(90:10).The characteristic drop height(H_(50))of DAAF/RDX(higher than 100 cm)composites was higher than that of raw RDX(25 cm),suggesting significant improvements in mechanical safety.The preparation of DAAF/RDX microspheres is promising for the desensitization of RDX and useful for the formation of other materials and future wide applications.展开更多
This review covers recent advances in the synthesis and energetic performance of nitrogen-rich 1,2,4-oxadiazole-azoles-based energetic materials.These materials comprise of 1,2,4-oxadiazole subunit as a key structural...This review covers recent advances in the synthesis and energetic performance of nitrogen-rich 1,2,4-oxadiazole-azoles-based energetic materials.These materials comprise of 1,2,4-oxadiazole subunit as a key structural motif linked to different nitrogen-rich or nitrogen-oxygen azoles:tetrazole,furazan,furoxan,1,3,4-oxadiazole,pyrazole,and triazole.Particular attention is devoted to the introduction of various energetic groups including nitro,nitramino,azo,azoxy,dinitromethyl,trinitroethyl moieties,and their combination.The physicochemical and available performance parameters including density,decomposition temperature,heat of formation,detonation pressure,detonation velocity,impact sensitivity,and friction sensitivity of typical energetic compounds are also provided and analyzed.Eventually,it was obtained that several screened compounds exhibit superior detonation properties and outstanding insensitivities,which can be classified as a new family of high-performance energetic materials.Additionally,1,2,4-oxadiazole-azoles-based energetic materials still have many thorough works to further exploited and studied,expecting to get very promising insensitive high explosives for practical application and industrialization.展开更多
The aim of this study is to investigate nonlinear bending for a 3-Dimensional(3D)braided composite cylindrical panel which has transverse loads on its finite length. By refining a micro-macro-mechanical model, the 3...The aim of this study is to investigate nonlinear bending for a 3-Dimensional(3D)braided composite cylindrical panel which has transverse loads on its finite length. By refining a micro-macro-mechanical model, the 3D braided composite can be treated as a representative average cell system. The geometric structural properties of its components deeply depend on their positions in the section of the cylindrical panel. The embedded elastic medium of the panel can be described by a Pasternak elastic foundation. Via using the shell theory of the von Ka′rma′nDonnell type of kinematic nonlinearity, governing equations can be established to get higherorder shear deformation. The mixed Galerkin-perturbation method is applied to get the nonlinear bending behavior of the 3D braided cylindrical panel with a simply supported boundary condition.Based on the analysis of the braided composite cylindrical panel with variable initial stress, geometric parameter, fiber volume fraction, and elastic foundation, serial numerical illustrations are archived to represent the appropriate nonlinear bending responses.展开更多
An atroposelective synthesis of a new class of 3,3'-bisindoles bearing axial and central chirality has been established via catalytic asymmetric addition reactions using isatin-derived imines as electrophiles(23 e...An atroposelective synthesis of a new class of 3,3'-bisindoles bearing axial and central chirality has been established via catalytic asymmetric addition reactions using isatin-derived imines as electrophiles(23 examples,up to 80% yield,>95:5 do 98:2 er).This approach takes advantage of chiral phosphoric acid-catalyzed dynamic kinetic resolution of 2-substituted 3,3'-bisindoles via nucleophilic addition of such substrates with isatin-derived imines.In this approach,isatin-derived imines acted as a class of competent electrophiles due to their high reactivity and bulky size,which provided an easy access to axially chiral 3,3'-bisindoles incorporated with a biologically important chiral 3-aminooxindole unit.This approach has greatly expanded the generality and applicability of the strategy of dynamic kinetic resolution for the synthesis of enantioenriched 3,3'-bisindole derivatives bearing both axial and central chirality.展开更多
Background:The effectiveness of acupuncture for insomnia and insomnia-related anxiety and depression has been widely investigated in clinical trials.However,whether higher dosage(more frequent)acupuncture can bring gr...Background:The effectiveness of acupuncture for insomnia and insomnia-related anxiety and depression has been widely investigated in clinical trials.However,whether higher dosage(more frequent)acupuncture can bring greater responses(a greater size of effect)is less understood.Objective:This study is designed to investigate whether a five-times weekly(5 Ts/w)electroacupuncture(EA)treatment is better than a three-times weekly(3 Ts/w)EA in alleviating sleep deprivation,and sleep disturbance-induced cognitive dysfunctions and negative emotions in rats through four various behavioral te sts.Methods:Forty-six male Sprague-Dawley rats were randomly divided into control group(n=10),model group(n=12),EA-3 Ts/w group(n=12),and EA-5 Ts/w group(n=12).Except for the control group,the other three groups were established as chronic sleep deprivation models via the modified multi-platform water environment methodology.Then,rats in both EA-3 Ts/w group and EA-5 Ts/w group received corresponding dosage of EA therapy,respectively.After modeling and interventions,all four groups received four behavioral tests as follows:(1)sleep behavioral monitoring and evaluation was achieved by Comprehensive Lab Animal Monitoring System(CLAMS).(2)Cognitive functions were assessed by Novel Object Recognition(NOR)test.(3)Depressive-like behaviors was evaluated by Open-Field(OF)test.(4)Anxietylike behaviors was appraised by Elevated Plus-Maze(EPM)test.After finishing the behavioral tests,the hippocampus of each rat was removed and its synaptic structure changes were observed under electron microscope.Results:(1)CLAMS:two EA groups derived more sleep time within 24 h than the model group(both P<0.05),and no statistical differences was found between these two EA groups(P>0.05).(2)NOR test:NOR ratio in the EA-3 Ts/w group was higher than that of the model group(P<0.05)but lower than that of either the control group(P<0.05)or the EA-5 Ts/w group(P<0.05).(3)OF test:the difference of horizontal movements between the EA-3 Ts/w group and the EA-5 Ts/w group was not significant(P>0.05),although both of them were lower than that of the control group(both P<0.05)but higher than that of the model group(P<0.05).(4)EPM test:no significant decline of open-arm total time(OT)was found in EA-3 Ts/w group(P>0.05)but was found in both the model group(P<0.05)and the EA-5 Ts/w group(P<0.05)compared to the control group.Conclusion:(1)Five-week EA treatment can partially mitigate cognitive dysfunctions,anxiety-like behaviors,and depressive behaviors in rats with sleep deprivation,and this effect might be associated with the repairs on mitochondrial damage in hippocampal neurons.(2)There is insufficient evidence supporting 3 Ts/w EA treatment is less effective than 5 Ts/w EA treatment in mitigating sleep deprivation symptoms and depressive behaviors induced by sleep deprivation among rats.(3)5 Ts/w EA treatment might be more effective than 3 Ts/w EA treatment in attenuating sleep deprivation-induced cognitive impairments while it might further increase rat’s anxiety-like behaviors at the same time.展开更多
Aims studying the ecological significance of highly specialized morpho-logical traits evolved by alpine plants could help us to understand the adaptation and evolution of these plants under severe alpine environ-ment....Aims studying the ecological significance of highly specialized morpho-logical traits evolved by alpine plants could help us to understand the adaptation and evolution of these plants under severe alpine environ-ment.We explored the adaptive significance of woolly and overlap-ping leaves for reproduction in Eriophyton wallichii,a perennial herb native to the subnival belt of the Himalaya-Hengduan mountains.Methods We examined whether the trichomes could influence the leaf wet-tability,temperature and leaf reflectance spectra in the lab.and we investigated the thermal benefits of the woolly and overlapping leaves for flowers and fruits in the field.Pollen viability and seed germination were also examined in the lab to assess whether these leaves enhance reproductive fitness.Important Findingsour results showed that dense trichomes impart good water repel-lency,absorption of solar radiation and accumulation of leaf heat.The woolly and overlapping leaves increased the interior tempera-ture of flowers and fruits to an optimal level on sunny hours,but prevented them from overheating when transient intense solar radi-ation occurs.This kept optimal temperatures in plants’reproduc-tive organs,thus promoting the development of pollen and seed in alpine environment.展开更多
Highly refractive and transparent polyamides containing thiadiazole units have been developed. These polymers were prepared by a polycondensation reaction of 4,4'-(1,3,4-thiadiazole-2,5-thio) his(methylene) diben...Highly refractive and transparent polyamides containing thiadiazole units have been developed. These polymers were prepared by a polycondensation reaction of 4,4'-(1,3,4-thiadiazole-2,5-thio) his(methylene) dibenzoyl chloride (TDTBM-DC) and diamine which contained thioether (--S--) and sulfone units. They showed good thermal stabilities such as a relatively high glass transition temperature of 206-233℃ and a 5% weight-loss temperature (T5%) of 376-395 ℃. The optical transmittance of the polymer at 450 nm is higher than 83%. The heterocycle units and plural --S-- linkages provide the polymer with a high refractive index of 1.716-1.725 at 633 nm and a low birefringence of 0.003-0.004. Also they showed improved solubility in polar aprotic solvents and could form moderate strength films with tensile strength of 72.8-83.1 MPa and storage modulus of 1.0-1.8 GPa (at 200 ℃).展开更多
基金supported by the National Key Research and Development Program of China(2022YFE0203900)Guangdong Key Research and Development Program(2021B0202040002 and 2022B1111030001)+4 种基金China Agriculture Research System(CARS-46)Guangdong Basic and Applied Basic Research Foundation(2021A1515010647)Basic and Applied Basic Research Project of Guangzhou Science and Technology Plan Project(202102020299)Science and Technology Planning Project of Guangdong(2023B1212060023)Guangdong Laboratory for Lingnan Modern Agriculture(NZ2021018)。
文摘The von Hippel-Lindau tumor suppressor protein(VHL),an E3 ubiquitin ligase,functions as a critical regulator of the oxygen-sensing pathway for targeting hypoxia-inducible factors.Recent evidence suggests that mammalian VHL may also be critical to the NF-κB signaling pathway,although the specific molecular mechanisms remain unclear.Herein,the roles of mandarin fish(Siniperca chuatsi)VHL(scVHL)in the NF-κB signaling pathway and mandarin fish ranavirus(MRV)replication were explored.The transcription of scVHL was induced by immune stimulation and MRV infection,indicating a potential role in innate immunity.Dual-luciferase reporter gene assays and reverse transcription quantitative PCR(RT-qPCR)results demonstrated that scVHL evoked and positively regulated the NF-κB signaling pathway.Treatment with NF-κB signaling pathway inhibitors indicated that the role of scVHL may be mediated through scIKKα,scIKKβ,scIκBα,or scp65.Co-immunoprecipitation(Co-IP)analysis identified scIκBαas a novel target protein of scVHL.Moreover,scVHL targeted scIκBαto catalyze the formation of K63-linked polyubiquitin chains to activate the NF-κB signaling pathway.Following MRV infection,NF-κB signaling remained activated,which,in turn,promoted MRV replication.These findings suggest that scVHL not only positively regulates NF-κB but also significantly enhances MRV replication.This study reveals a novel function of scVHL in NF-κB signaling and viral infection in fish.
文摘AIM:To explore clinicopathologic characteristics of intrahepatic cholangiocarcinoma (ICC) in patients with positive serum a-fetoprotein (AFP). METHODS:One hundred and thirty one patients who underwent surgical dissection for pathologically confirmed ICC were divided into a positive AFP (> 20 ng/mL) group (n = 32) and a negative AFP group (n = 99), whose clinicopathologic features were analyzed and compared. RESULTS:The positive rate of HBsAg and liver cirrhosis of the positive AFP group was higher than that of the negative AFP group, while the positive rate of CA19-9 (> 37 U/mL) and the lymph node metastasis rate was lower. CONCLUSION:ICC patients with positive AFP share many clinicopathologic similarities with hepatocellular carcinoma.
基金supported by the National Natural Science Foundation of China (grant nos. 31460050 and 31760048 to Yong-Hong Zhang)
文摘Cypripedium tibeticum is a threatened orchid which efficient conservation requires knowledge of its extent and structure of genetic variation. Using two chloroplast DNA fragments(rps16 and trnL-F), we analyzed 157 individuals from 9 populations representing the species range in China. Seven haplotypes were identified. C. tibeticum had high total genetic diversity(H_T=0.80) with major contribution to this diversity made by among-population component(G_ST=0.64, Ф_ST= 0.86). However, despite high population differentiation there was no clear phylogeographic structure. The populations CY and DC made the greatest contribution to the total gene diversity as well as allelic richness. The possible mechanisms and implications of these findings for conservation of the species are discussed.
基金the National Key R&D Program of China(2017YF0505200 to H.Sun)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA 20050203 to H.Sun)+1 种基金the Key Program of the National Natural Science Foundation of China(U1802232 to H.Sun)National Natural Science Foundation of China(grant 31700284 to D.L.Peng,31670206 to Z.M.Li and 31900185 to L.E.Yang)。
文摘Primula beesiana Forr.is an attractive wildflower endemically distributed in the wet habitats of subalpine/alpine regions of southwestern China.This study is an attempt to understand how this plant adapts to wet habitats and high altitudes.Specifically,we examined the effects of cold stratification,light,GA3,KNO3,and temperature on P.beesiana seed germination.KNO3 and GA3 increased germination percentage and germination rate compared to control treatments at 15/5 and 25/15℃.Untreated seeds germinated well(>80%)at higher temperatures(20,25 and 28℃),whereas at lower(5,10 and15℃)and extremely high temperatures(30 and 32℃)germination decreased significantly.However,after cold stratification(4-16 weeks),the germination percentage of P.beesiana seeds at low temperatures(5-15℃)and the germination rate at high temperatures(30℃)increased significantly,suggesting that P.beesiana has type 3 non-deep physiological dormancy.The base temperature and thermal time for germination decreased in seeds that were cold stratified for 16 weeks.Cold-stratified seeds incubated at fluctuating temperatures(especially at 15/5℃)had significantly high germination percentages and germination rates in light,but not in dark,compared to the corresponding constant temperature(10℃).Seeds had a strict light requirement at all temperatures,even after experiencing cold stratification;however,the combinations of cold stratification and fluctuating temperature increased germination when seeds were transferred from dark to light.Such dormancy/germination responses to light and temperature are likely mechanisms that ensure germination occurs only in spring and at/near the soil surface,thus avoiding seedling death by freezing,inundation and/or germination deep in the soil.
基金This work was financially supported by the National Natural Science Foundation of China(52074089 and 52104064)Natural Science Foundation of Heilongjiang Province of China(LH2019E019).
文摘As the main link of ground engineering,crude oil gathering and transportation systems require huge energy consumption and complex structures.It is necessary to establish an energy efficiency evaluation system for crude oil gathering and transportation systems and identify the energy efficiency gaps.In this paper,the energy efficiency evaluation system of the crude oil gathering and transportation system in an oilfield in western China is established.Combined with the big data analysis method,the GA-BP neural network is used to establish the energy efficiency index prediction model for crude oil gathering and transportation systems.The comprehensive energy consumption,gas consumption,power consumption,energy utilization rate,heat utilization rate,and power utilization rate of crude oil gathering and transportation systems are predicted.Considering the efficiency and unit consumption index of the crude oil gathering and transportation system,the energy efficiency evaluation system of the crude oil gathering and transportation system is established based on a game theory combined weighting method and TOPSIS evaluation method,and the subjective weight is determined by the triangular fuzzy analytic hierarchy process.The entropy weight method determines the objective weight,and the combined weight of game theory combines subjectivity with objectivity to comprehensively evaluate the comprehensive energy efficiency of crude oil gathering and transportation systems and their subsystems.Finally,the weak links in energy utilization are identified,and energy conservation and consumption reduction are improved.The above research provides technical support for the green,efficient and intelligent development of crude oil gathering and transportation systems.
基金the National Natural Science Foundation of China(No.22005275)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(STIP,No.2019L0584)+2 种基金Equipment Pre-research Weapons Industry Joint Fund(No.6141B012896)Equipment Pre-research Key Laboratory Fund(No.6142020305)the Advantage Disciplines Climbing Plan of Shanxi Province.
文摘Insensitive energetic materials are promising in the defense weapons field.However,energetic materials still suffer from great challenges and the concern about their safety limits their utilization.In this work,insensitive energetic explosive 3,30-diamino-4,40-azoxyfurazan/hexahydro-1,3,5-trinitro-1,3,5-triazine(DAAF/RDX)microspheres were fabricated by self-assembly method.Rod-like DAAF/RDX was prepared by mechanical ball milling for comparison.DAAF/RDX composites with different mass ratios(90:10,80:20,and 70:30)were obtained.The morphologies and structures of as-obtained DAAF/RDX composites were characterized by scanning electron microscopy(SEM),powder x-ray diffraction(PXRD)and fourier transform infrared spectroscopy(FT-IR).The results showed that DAAF/RDX microspheres exhibited regular shaped microspheres with sizes from 0.5 to 1.2 mm.There was no crystal transition during the modification process.The thermal properties of as-obtained materials were then evaluated by differential scanning calorimetry(DSC)and materials studio software.DAAF/RDX microspheres showed an advanced decomposition peak temperature compared with rod-like DAAF/RDX.The binding energy and peak temperature values at zeroβ_(i)(T_(P0))of DAAF/RDX(90:10)increased by 36.77 kJ/mol,1.6℃,and 58.11 kJ/mol,12.3℃compared to DAAF/RDX(80:20)and DAAF/RDX(70:30),indicating the better thermal stability of DAAF/RDX(90:10).The characteristic drop height(H_(50))of DAAF/RDX(higher than 100 cm)composites was higher than that of raw RDX(25 cm),suggesting significant improvements in mechanical safety.The preparation of DAAF/RDX microspheres is promising for the desensitization of RDX and useful for the formation of other materials and future wide applications.
基金We are thankful to the NSAF(No.U1830134)NSFC(No.21905023 and 22175025)+1 种基金State Key Laboratory of Explosion Science and Technology(No.YBKT21-02)Open Research Fund Program of CAS Key Laboratory of Energy Regulation Materials(No.ORFP2020-01)for their generous financial support.
文摘This review covers recent advances in the synthesis and energetic performance of nitrogen-rich 1,2,4-oxadiazole-azoles-based energetic materials.These materials comprise of 1,2,4-oxadiazole subunit as a key structural motif linked to different nitrogen-rich or nitrogen-oxygen azoles:tetrazole,furazan,furoxan,1,3,4-oxadiazole,pyrazole,and triazole.Particular attention is devoted to the introduction of various energetic groups including nitro,nitramino,azo,azoxy,dinitromethyl,trinitroethyl moieties,and their combination.The physicochemical and available performance parameters including density,decomposition temperature,heat of formation,detonation pressure,detonation velocity,impact sensitivity,and friction sensitivity of typical energetic compounds are also provided and analyzed.Eventually,it was obtained that several screened compounds exhibit superior detonation properties and outstanding insensitivities,which can be classified as a new family of high-performance energetic materials.Additionally,1,2,4-oxadiazole-azoles-based energetic materials still have many thorough works to further exploited and studied,expecting to get very promising insensitive high explosives for practical application and industrialization.
基金supported in part by grants from the National Natural Science Foundation of China (Nos. 51375308 and 51775346)
文摘The aim of this study is to investigate nonlinear bending for a 3-Dimensional(3D)braided composite cylindrical panel which has transverse loads on its finite length. By refining a micro-macro-mechanical model, the 3D braided composite can be treated as a representative average cell system. The geometric structural properties of its components deeply depend on their positions in the section of the cylindrical panel. The embedded elastic medium of the panel can be described by a Pasternak elastic foundation. Via using the shell theory of the von Ka′rma′nDonnell type of kinematic nonlinearity, governing equations can be established to get higherorder shear deformation. The mixed Galerkin-perturbation method is applied to get the nonlinear bending behavior of the 3D braided cylindrical panel with a simply supported boundary condition.Based on the analysis of the braided composite cylindrical panel with variable initial stress, geometric parameter, fiber volume fraction, and elastic foundation, serial numerical illustrations are archived to represent the appropriate nonlinear bending responses.
基金financial support from NSFC(Nos.21772069 and 21831007)Six Kinds of Talents Project of Jiangsu Province(SWYY-025).
文摘An atroposelective synthesis of a new class of 3,3'-bisindoles bearing axial and central chirality has been established via catalytic asymmetric addition reactions using isatin-derived imines as electrophiles(23 examples,up to 80% yield,>95:5 do 98:2 er).This approach takes advantage of chiral phosphoric acid-catalyzed dynamic kinetic resolution of 2-substituted 3,3'-bisindoles via nucleophilic addition of such substrates with isatin-derived imines.In this approach,isatin-derived imines acted as a class of competent electrophiles due to their high reactivity and bulky size,which provided an easy access to axially chiral 3,3'-bisindoles incorporated with a biologically important chiral 3-aminooxindole unit.This approach has greatly expanded the generality and applicability of the strategy of dynamic kinetic resolution for the synthesis of enantioenriched 3,3'-bisindole derivatives bearing both axial and central chirality.
基金Natural Science Foundation of Shanghai:No.17ZR1428100TCM Science and Technology Innovation Project of Shanghai Health and Family Planning Commission:No.ZYKC20161016+1 种基金Special Project for Clinical ResearchShanghai Municipal Health Commission:No.20174Y0009。
文摘Background:The effectiveness of acupuncture for insomnia and insomnia-related anxiety and depression has been widely investigated in clinical trials.However,whether higher dosage(more frequent)acupuncture can bring greater responses(a greater size of effect)is less understood.Objective:This study is designed to investigate whether a five-times weekly(5 Ts/w)electroacupuncture(EA)treatment is better than a three-times weekly(3 Ts/w)EA in alleviating sleep deprivation,and sleep disturbance-induced cognitive dysfunctions and negative emotions in rats through four various behavioral te sts.Methods:Forty-six male Sprague-Dawley rats were randomly divided into control group(n=10),model group(n=12),EA-3 Ts/w group(n=12),and EA-5 Ts/w group(n=12).Except for the control group,the other three groups were established as chronic sleep deprivation models via the modified multi-platform water environment methodology.Then,rats in both EA-3 Ts/w group and EA-5 Ts/w group received corresponding dosage of EA therapy,respectively.After modeling and interventions,all four groups received four behavioral tests as follows:(1)sleep behavioral monitoring and evaluation was achieved by Comprehensive Lab Animal Monitoring System(CLAMS).(2)Cognitive functions were assessed by Novel Object Recognition(NOR)test.(3)Depressive-like behaviors was evaluated by Open-Field(OF)test.(4)Anxietylike behaviors was appraised by Elevated Plus-Maze(EPM)test.After finishing the behavioral tests,the hippocampus of each rat was removed and its synaptic structure changes were observed under electron microscope.Results:(1)CLAMS:two EA groups derived more sleep time within 24 h than the model group(both P<0.05),and no statistical differences was found between these two EA groups(P>0.05).(2)NOR test:NOR ratio in the EA-3 Ts/w group was higher than that of the model group(P<0.05)but lower than that of either the control group(P<0.05)or the EA-5 Ts/w group(P<0.05).(3)OF test:the difference of horizontal movements between the EA-3 Ts/w group and the EA-5 Ts/w group was not significant(P>0.05),although both of them were lower than that of the control group(both P<0.05)but higher than that of the model group(P<0.05).(4)EPM test:no significant decline of open-arm total time(OT)was found in EA-3 Ts/w group(P>0.05)but was found in both the model group(P<0.05)and the EA-5 Ts/w group(P<0.05)compared to the control group.Conclusion:(1)Five-week EA treatment can partially mitigate cognitive dysfunctions,anxiety-like behaviors,and depressive behaviors in rats with sleep deprivation,and this effect might be associated with the repairs on mitochondrial damage in hippocampal neurons.(2)There is insufficient evidence supporting 3 Ts/w EA treatment is less effective than 5 Ts/w EA treatment in mitigating sleep deprivation symptoms and depressive behaviors induced by sleep deprivation among rats.(3)5 Ts/w EA treatment might be more effective than 3 Ts/w EA treatment in attenuating sleep deprivation-induced cognitive impairments while it might further increase rat’s anxiety-like behaviors at the same time.
基金Natural National Science Foundation of China(U1136601 to H.S.,31360049 to Z.M.L.and 31270005,31470321 to Y.Y.)Strategic Priority Research Program(B)of the Chinese Academy of Science(XDB03030112 to H.S.).
文摘Aims studying the ecological significance of highly specialized morpho-logical traits evolved by alpine plants could help us to understand the adaptation and evolution of these plants under severe alpine environ-ment.We explored the adaptive significance of woolly and overlap-ping leaves for reproduction in Eriophyton wallichii,a perennial herb native to the subnival belt of the Himalaya-Hengduan mountains.Methods We examined whether the trichomes could influence the leaf wet-tability,temperature and leaf reflectance spectra in the lab.and we investigated the thermal benefits of the woolly and overlapping leaves for flowers and fruits in the field.Pollen viability and seed germination were also examined in the lab to assess whether these leaves enhance reproductive fitness.Important Findingsour results showed that dense trichomes impart good water repel-lency,absorption of solar radiation and accumulation of leaf heat.The woolly and overlapping leaves increased the interior tempera-ture of flowers and fruits to an optimal level on sunny hours,but prevented them from overheating when transient intense solar radi-ation occurs.This kept optimal temperatures in plants’reproduc-tive organs,thus promoting the development of pollen and seed in alpine environment.
基金financially supported by the Youth Fund of Sichuan University(No.2012SCU11009)
文摘Highly refractive and transparent polyamides containing thiadiazole units have been developed. These polymers were prepared by a polycondensation reaction of 4,4'-(1,3,4-thiadiazole-2,5-thio) his(methylene) dibenzoyl chloride (TDTBM-DC) and diamine which contained thioether (--S--) and sulfone units. They showed good thermal stabilities such as a relatively high glass transition temperature of 206-233℃ and a 5% weight-loss temperature (T5%) of 376-395 ℃. The optical transmittance of the polymer at 450 nm is higher than 83%. The heterocycle units and plural --S-- linkages provide the polymer with a high refractive index of 1.716-1.725 at 633 nm and a low birefringence of 0.003-0.004. Also they showed improved solubility in polar aprotic solvents and could form moderate strength films with tensile strength of 72.8-83.1 MPa and storage modulus of 1.0-1.8 GPa (at 200 ℃).