English as an international language,English writing is a very important skill as an important form of language output,which is not only an important means of expressing emotions and awareness,but also reflects the ab...English as an international language,English writing is a very important skill as an important form of language output,which is not only an important means of expressing emotions and awareness,but also reflects the ability to use language in an integrated way.In language teaching,the development of English writing skills is an important and challenging teaching task.English writing language is expressed not only at the basic level of vocabulary,grammar,and sentence structure,but also at the higher-order level of text organization,logical reasoning,and argumentation.However,in traditional English writing teaching,students usually do not have the opportunity to have an in-depth experience of the context of the topic,which leads to a lack of motivation and poor writing results.Therefore,this study developed an SVVR learning system based on spherical video-based virtual reality(SVVR)technology and conducted a quasi-experiment in a university English major classroom.The results of the study showed that the SVVR-supported approach to English writing could improve students'writing performance,enrich writing content,and increase learning motivation.展开更多
The petroleum industry plays an essential role in driving China's economic development.In the past few decades,severa reforms in the petroleum industry have been implemented;however,there are still some is sues th...The petroleum industry plays an essential role in driving China's economic development.In the past few decades,severa reforms in the petroleum industry have been implemented;however,there are still some is sues that have not been resolved Moreover,with the new-normal economy,the transition to green energy and international trade disputes,the petroleum marke is also facing emerging challenges.Therefore,the purpose of the present study is to review the historical development o China's petroleum market,identify the current challenges and propose corresponding countermeasures for future prospects As a conclusion,five main challenges are highlighted totally,namely lack of marketization,excess oil refining capacity,hig external dependency,environment pollution and unstable international trading relationship.To address these challenges it is encouraged to deepen petroleum market reform,accelerate the elimination of inefficient refining capacity,diversify of supply sources,as well as improve domestic petroleum enterprises'ability to resist price risks.展开更多
BACKGROUND Extracellular vesicles(EVs)derived from hypoxia-preconditioned(HP)mesenchymal stem cells(MSCs)have better cardioprotective effects against myocardial infarction(MI)in the early stage than EVs isolated from ...BACKGROUND Extracellular vesicles(EVs)derived from hypoxia-preconditioned(HP)mesenchymal stem cells(MSCs)have better cardioprotective effects against myocardial infarction(MI)in the early stage than EVs isolated from normoxic(NC)-MSCs.However,the cardioprotective mechanisms of HP-EVs are not fully understood.AIM To explore the cardioprotective mechanism of EVs derived from HP MSCs.METHODS We evaluated the cardioprotective effects of HP-EVs or NC-EVs from mouse adipose-derived MSCs(ADSCs)following hypoxia in vitro or MI in vivo,in order to improve the survival of cardiomyocytes(CMs)and restore cardiac function.The degree of CM apoptosis in each group was assessed by the terminal deoxynucleotidyl transferase dUTP nick end-labeling and Annexin V/PI assays.MicroRNA(miRNA)sequencing was used to investigate the functional RNA diversity between HP-EVs and NC-EVs from mouse ADSCs.The molecular mechanism of EVs in mediating thioredoxin-interacting protein(TXNIP)was verified by the dual-luciferase reporter assay.Co-immunoprecipitation,western blotting,and immunofluorescence were performed to determine if TXNIP is involved in hypoxia-inducible factor-1 alpha(HIF-1α)ubiquitination and degradation via the chromosomal region maintenance-1(CRM-1)-dependent nuclear transport pathway.RESULTS HP-EVs derived from MSCs reduced both infarct size(necrosis area)and apoptotic degree to a greater extent than NC-EVs from CMs subjected to hypoxia in vitro and mice with MI in vivo.Sequencing of EV-associated miRNAs showed the upregulation of 10 miRNAs predicted to bind TXNIP,an oxidative stress-associated protein.We showed miRNA224-5p,the most upregulated miRNA in HP-EVs,directly combined the 3’untranslated region of TXNIP and demonstrated its critical protective role against hypoxia-mediated CM injury.Our results demonstrated that MI triggered TXNIP-mediated HIF-1αubiquitination and degradation in the CRM-1-mediated nuclear transport pathway in CMs,which led to aggravated injury and hypoxia tolerance in CMs in the early stage of MI.CONCLUSION The anti-apoptotic effects of HP-EVs in alleviating MI and the hypoxic conditions of CMs until reperfusion therapy may partly result from EV miR-224-5p targeting TXNIP.展开更多
Selecting check index quantitatively is the core of the calibration of micro traffic simulation parameters at signal intersection. Five indexes in the node (intersection) module of VISSIM were selected as the check in...Selecting check index quantitatively is the core of the calibration of micro traffic simulation parameters at signal intersection. Five indexes in the node (intersection) module of VISSIM were selected as the check index set. Twelve simulation parameters in the core module were selected as the simulation parameters set. Optimal process of parameter calibration was proposed and model of the intersection of Huangcun west street and Xinghua street in Beijing was built in VISSIM to verify it. The sensitivity analysis between each check index and simulation parameter in their own set was conducted respectively. Sensitive parameter sets of different check indices were obtained and compared. The results show that different indexes have different size of set, and average vehicle delay’s is maximum, so it’s necessary to select index quantitatively. The results can provide references for scientific selection of the check indexes and improve the study efficiency of parameter calibration.展开更多
Nanofluids have been effective chemical additives for enhanced oil recovery(EOR)in tight oil reservoirs due to their special properties.However,oil imbibition recoveries vary for different nanofluids.The oil/water dis...Nanofluids have been effective chemical additives for enhanced oil recovery(EOR)in tight oil reservoirs due to their special properties.However,oil imbibition recoveries vary for different nanofluids.The oil/water distribution in rocks during imbibition using various nanofluids was less discussed in previous studies.In this study,we systematically examined the imbibition efficiencies of various nanofluids at60℃.Furthermore,the migration of nanofluids and oil distribution in the rock pores were monitored using nuclear magnetic resonance(NMR).The nanofluids were prepared by dispersing silica nanoparticles and five different types of surfactants i.e.,anionic-nonionic,anionic,nonionic,amphoteric and cationic surfactants in deionized(DI)water.Subsequently,interfacial tension(IFT)and contact angle measurements were conducted to reveal the underlying EOR mechanisms of various nanofluids.The experimental results showed that the EOR potential of the different types of nanofluids was in the order anionic-nonionic>anionic>nonionic>amphoteric>cationic>brine.Anionic-nonionic(sodium lauryl ether sulfate(SLES))and anionic(sodium dodecyl sulfonate(SDS))nanofluids exhibited excellent capability of wettability alteration,and increased oil recovery by 27.96%and 23.08%,respectively,compared to brine.The NMR results also showed that mesopores(0.1-1μm)were the dominant developed pores in the rocks,and contributed the most to imbibition efficiency.In addition,the imbibition of nanofluids initially took place in mesopores and micropores before moving into macropores.This study provides fundamental information on the selection of nanofluids for EOR in tight oil reservoirs.The study also improved the understanding of oil/water distribution during the imbibition of the proposed nanofluids.展开更多
Lymphoma rarely occurs during pregnancy, making this condition difficult to define. Lymphomas that occur in reproductive organs during pregnancy exhibit unique clinical characteristics. Among the limited cases, non-Ho...Lymphoma rarely occurs during pregnancy, making this condition difficult to define. Lymphomas that occur in reproductive organs during pregnancy exhibit unique clinical characteristics. Among the limited cases, non-Hodgkin's lymphoma(NHL) shows a considerably higher incidence rate than Hodgkin's lymphoma(HL); NHL also displays clinical characteristics, such as high aggressiveness, advanced stage, and poor outcome. This study reports on four cases of lymphomas in non-gonadal organs(HL,n=2; NHL, n=2) during pregnancy. The tumors rapidly progressed in all patients during pregnancy but remitted at the end of pregnancy and/or therapy. The two HL cases were nodular sclerosis classical HL and treated with chemotherapy after terminating the pregnancy. One of the NHL cases was primary cutaneous follicular center lymphoma, a B cell-derived indolent lymphoma.The patient was followed up without any therapy after terminating her pregnancy. The other case was a follicular lymphoma grade3 B, which was treated with chemotherapy after delivery. We also conducted a literature review of 165 lymphoma cases occurring during pregnancy reported from 1976 to 2013 to reveal the correlation between pregnancy and lymphoma progression.Immunohistochemistry studies were performed to determine the expression of estrogen/progesterone receptors(ER/PR), and ER was weakly positive and sporadic. We concluded that lymphomas occurring during pregnancy should be managed with a prompt and reasonable treatment. High estrogen level in maternal body may affect lymphoma progression.展开更多
FePt nanoparticles(NPs)have attracted a great deal of attention in biomedical applications due to their excellent superparamagnetic property and anticancer activity,which display promising potential as the MRI/CT cont...FePt nanoparticles(NPs)have attracted a great deal of attention in biomedical applications due to their excellent superparamagnetic property and anticancer activity,which display promising potential as the MRI/CT contrast imag-ing agent for cancer detection and therapy.In this study,the suppression mechanism induced by FePt NPs on U251 cells is investigated.Glioma U251 cells are co-cultured with FePt NPs at different concentrations,and the intra-cellular oxidative stress was studied by detecting the activities of various redox enzymes and expression of several apoptosis-related proteins.The cell viability assay shows that the highest suppression on the proliferation of glioma U251 cells is 10.5%±5.6%after treatment with 5μg·ml^(-1)FePt NPs for 24 h.In this case,the LDH release remarkably increases.Flow cytometry and fluorescence assay show that FePt NPs promote the apoptosis and G0/G1 phase arrest of U251 cells.展开更多
The abuse of antibiotics has become a global concern,thus it is significant to develop simple antibiotic assays.Herein,a novel type of lanthanide-doped bovine serum albumin(BSA)derived carbon dots(BCDs)dubbed Eu-BCDs ...The abuse of antibiotics has become a global concern,thus it is significant to develop simple antibiotic assays.Herein,a novel type of lanthanide-doped bovine serum albumin(BSA)derived carbon dots(BCDs)dubbed Eu-BCDs has been unveiled for ratiometric fluorescent detection of tetracycline(TC),which was formed from the one-step hydrothermal reaction of Eu^(3+)and BSA.Upon challenge with TC,the blue fluorescence of Eu-BCDs at 448 nm was gradually quenched due to the internal filtration effect,while the characteristic red fluorescence of Eu^(3+)at 618 nm was significantly enhanced owning to the antenna effect,leading to the ratiometric fluorescent detection of TC with fast response(2 min),a wide linear dynamic range(0-80μmol/L),and high selectivity and sensitivity(limit of detection(LOD)of 3 nmol/L).Moreover,Eu-BCDs can be successfully applied for the ratiometric fluorescent detection of TC in environmental and biological samples,such as river water,milk,honey and serum.The Eu-BCDs sensing platform would have great application potential in view of its simple preparation,rapid response,high sensitivity and good selectivity.展开更多
The intestine is the natural habitat for a large and dynamic bacterial community,which perform vital metabolic and immune functions that significantly effect the nutritional and health status of the host.The major phy...The intestine is the natural habitat for a large and dynamic bacterial community,which perform vital metabolic and immune functions that significantly effect the nutritional and health status of the host.The major physiological functions of intestinal flora include metabolic activities that lead to important trophic effects on immune structure and function as well as protection of the colonized host against invasion by transient microbes.The intestinal flora is both a target for nutritional intervention and a factor influencing the biological activity of food compounds acquired orally.Marine environments,as a source of diverse organic compounds,can supply us with a number of beneficial and health-promoting ingredients.This review focuses on the physiological functions of intestinal flora and reciprocal interactions between intestinal flora and dietary marine components including polysaccharides,lipids,protein,taurine,carotenoids,minerals,and polyphenols.This review can serve as a valuable reference regarding the consumption of seafood and marine nutraceuticals.展开更多
文摘English as an international language,English writing is a very important skill as an important form of language output,which is not only an important means of expressing emotions and awareness,but also reflects the ability to use language in an integrated way.In language teaching,the development of English writing skills is an important and challenging teaching task.English writing language is expressed not only at the basic level of vocabulary,grammar,and sentence structure,but also at the higher-order level of text organization,logical reasoning,and argumentation.However,in traditional English writing teaching,students usually do not have the opportunity to have an in-depth experience of the context of the topic,which leads to a lack of motivation and poor writing results.Therefore,this study developed an SVVR learning system based on spherical video-based virtual reality(SVVR)technology and conducted a quasi-experiment in a university English major classroom.The results of the study showed that the SVVR-supported approach to English writing could improve students'writing performance,enrich writing content,and increase learning motivation.
基金support provided by the National Natural Science Foundation of China(Nos.71974197 and 71774171)Beijing Social Science Fund(No.18GLC084)。
文摘The petroleum industry plays an essential role in driving China's economic development.In the past few decades,severa reforms in the petroleum industry have been implemented;however,there are still some is sues that have not been resolved Moreover,with the new-normal economy,the transition to green energy and international trade disputes,the petroleum marke is also facing emerging challenges.Therefore,the purpose of the present study is to review the historical development o China's petroleum market,identify the current challenges and propose corresponding countermeasures for future prospects As a conclusion,five main challenges are highlighted totally,namely lack of marketization,excess oil refining capacity,hig external dependency,environment pollution and unstable international trading relationship.To address these challenges it is encouraged to deepen petroleum market reform,accelerate the elimination of inefficient refining capacity,diversify of supply sources,as well as improve domestic petroleum enterprises'ability to resist price risks.
基金Supported by National Natural Science Foundation of China,No. 81870264 and No. 81470546the Shanghai Committee of Science and Technology,No. 18411950500+1 种基金the Major Disease Joint Project of Shanghai Health System,No. 2014ZYJB0501Talent Cultivation Project of The Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine,No. JC202005
文摘BACKGROUND Extracellular vesicles(EVs)derived from hypoxia-preconditioned(HP)mesenchymal stem cells(MSCs)have better cardioprotective effects against myocardial infarction(MI)in the early stage than EVs isolated from normoxic(NC)-MSCs.However,the cardioprotective mechanisms of HP-EVs are not fully understood.AIM To explore the cardioprotective mechanism of EVs derived from HP MSCs.METHODS We evaluated the cardioprotective effects of HP-EVs or NC-EVs from mouse adipose-derived MSCs(ADSCs)following hypoxia in vitro or MI in vivo,in order to improve the survival of cardiomyocytes(CMs)and restore cardiac function.The degree of CM apoptosis in each group was assessed by the terminal deoxynucleotidyl transferase dUTP nick end-labeling and Annexin V/PI assays.MicroRNA(miRNA)sequencing was used to investigate the functional RNA diversity between HP-EVs and NC-EVs from mouse ADSCs.The molecular mechanism of EVs in mediating thioredoxin-interacting protein(TXNIP)was verified by the dual-luciferase reporter assay.Co-immunoprecipitation,western blotting,and immunofluorescence were performed to determine if TXNIP is involved in hypoxia-inducible factor-1 alpha(HIF-1α)ubiquitination and degradation via the chromosomal region maintenance-1(CRM-1)-dependent nuclear transport pathway.RESULTS HP-EVs derived from MSCs reduced both infarct size(necrosis area)and apoptotic degree to a greater extent than NC-EVs from CMs subjected to hypoxia in vitro and mice with MI in vivo.Sequencing of EV-associated miRNAs showed the upregulation of 10 miRNAs predicted to bind TXNIP,an oxidative stress-associated protein.We showed miRNA224-5p,the most upregulated miRNA in HP-EVs,directly combined the 3’untranslated region of TXNIP and demonstrated its critical protective role against hypoxia-mediated CM injury.Our results demonstrated that MI triggered TXNIP-mediated HIF-1αubiquitination and degradation in the CRM-1-mediated nuclear transport pathway in CMs,which led to aggravated injury and hypoxia tolerance in CMs in the early stage of MI.CONCLUSION The anti-apoptotic effects of HP-EVs in alleviating MI and the hypoxic conditions of CMs until reperfusion therapy may partly result from EV miR-224-5p targeting TXNIP.
文摘Selecting check index quantitatively is the core of the calibration of micro traffic simulation parameters at signal intersection. Five indexes in the node (intersection) module of VISSIM were selected as the check index set. Twelve simulation parameters in the core module were selected as the simulation parameters set. Optimal process of parameter calibration was proposed and model of the intersection of Huangcun west street and Xinghua street in Beijing was built in VISSIM to verify it. The sensitivity analysis between each check index and simulation parameter in their own set was conducted respectively. Sensitive parameter sets of different check indices were obtained and compared. The results show that different indexes have different size of set, and average vehicle delay’s is maximum, so it’s necessary to select index quantitatively. The results can provide references for scientific selection of the check indexes and improve the study efficiency of parameter calibration.
基金financial support from the National Natural Science Foundation of China(No.51974282,52074249,51874261)Fundamental Research Funds for the Central Universities(2-9-2019-103)Key Research and Development Program of Shaanxi(No.2021GY-112)。
文摘Nanofluids have been effective chemical additives for enhanced oil recovery(EOR)in tight oil reservoirs due to their special properties.However,oil imbibition recoveries vary for different nanofluids.The oil/water distribution in rocks during imbibition using various nanofluids was less discussed in previous studies.In this study,we systematically examined the imbibition efficiencies of various nanofluids at60℃.Furthermore,the migration of nanofluids and oil distribution in the rock pores were monitored using nuclear magnetic resonance(NMR).The nanofluids were prepared by dispersing silica nanoparticles and five different types of surfactants i.e.,anionic-nonionic,anionic,nonionic,amphoteric and cationic surfactants in deionized(DI)water.Subsequently,interfacial tension(IFT)and contact angle measurements were conducted to reveal the underlying EOR mechanisms of various nanofluids.The experimental results showed that the EOR potential of the different types of nanofluids was in the order anionic-nonionic>anionic>nonionic>amphoteric>cationic>brine.Anionic-nonionic(sodium lauryl ether sulfate(SLES))and anionic(sodium dodecyl sulfonate(SDS))nanofluids exhibited excellent capability of wettability alteration,and increased oil recovery by 27.96%and 23.08%,respectively,compared to brine.The NMR results also showed that mesopores(0.1-1μm)were the dominant developed pores in the rocks,and contributed the most to imbibition efficiency.In addition,the imbibition of nanofluids initially took place in mesopores and micropores before moving into macropores.This study provides fundamental information on the selection of nanofluids for EOR in tight oil reservoirs.The study also improved the understanding of oil/water distribution during the imbibition of the proposed nanofluids.
文摘Lymphoma rarely occurs during pregnancy, making this condition difficult to define. Lymphomas that occur in reproductive organs during pregnancy exhibit unique clinical characteristics. Among the limited cases, non-Hodgkin's lymphoma(NHL) shows a considerably higher incidence rate than Hodgkin's lymphoma(HL); NHL also displays clinical characteristics, such as high aggressiveness, advanced stage, and poor outcome. This study reports on four cases of lymphomas in non-gonadal organs(HL,n=2; NHL, n=2) during pregnancy. The tumors rapidly progressed in all patients during pregnancy but remitted at the end of pregnancy and/or therapy. The two HL cases were nodular sclerosis classical HL and treated with chemotherapy after terminating the pregnancy. One of the NHL cases was primary cutaneous follicular center lymphoma, a B cell-derived indolent lymphoma.The patient was followed up without any therapy after terminating her pregnancy. The other case was a follicular lymphoma grade3 B, which was treated with chemotherapy after delivery. We also conducted a literature review of 165 lymphoma cases occurring during pregnancy reported from 1976 to 2013 to reveal the correlation between pregnancy and lymphoma progression.Immunohistochemistry studies were performed to determine the expression of estrogen/progesterone receptors(ER/PR), and ER was weakly positive and sporadic. We concluded that lymphomas occurring during pregnancy should be managed with a prompt and reasonable treatment. High estrogen level in maternal body may affect lymphoma progression.
基金Project supported by the National Natural Science Foundation of China(No.11502291)the Fund of Outstanding Doctoral Dissertation from the Ministry of Education of China(No.201460)
基金the Opening fund of Hubei Key Laboratory of Bioinorganic Chemistry&Materia Medica(No.BCMM201806)the Basic Research Project of Wuhan Science and Technology Bureau(No.2014060101010041)。
文摘FePt nanoparticles(NPs)have attracted a great deal of attention in biomedical applications due to their excellent superparamagnetic property and anticancer activity,which display promising potential as the MRI/CT contrast imag-ing agent for cancer detection and therapy.In this study,the suppression mechanism induced by FePt NPs on U251 cells is investigated.Glioma U251 cells are co-cultured with FePt NPs at different concentrations,and the intra-cellular oxidative stress was studied by detecting the activities of various redox enzymes and expression of several apoptosis-related proteins.The cell viability assay shows that the highest suppression on the proliferation of glioma U251 cells is 10.5%±5.6%after treatment with 5μg·ml^(-1)FePt NPs for 24 h.In this case,the LDH release remarkably increases.Flow cytometry and fluorescence assay show that FePt NPs promote the apoptosis and G0/G1 phase arrest of U251 cells.
基金We thank our colleagues Ya-Ying Zhou, Chun-Yan Deng and Li-Li Ren for their technical assistance. This work was supported by the National Natural Science Foundation of China （No. 81270857）, the Natural Science Foundation of Guangdong （No. $2013010014832）, and the Science and Technology Project of Shenzhen （JCYJ20120618153743791, GJHZ20120618153934353）.
基金Project supported by the National Natural Science Foundation of China(No.11502291)the Fund of Outstanding Doctoral Dissertation from the Ministry of Education of China(No.201460)
基金supported by the fund of the Shanghai Science and Technology Committee (19ZR1473300)the director fund of Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration (SHUES2022C03)the Fundamental Research Funds for the Central Universities
文摘The abuse of antibiotics has become a global concern,thus it is significant to develop simple antibiotic assays.Herein,a novel type of lanthanide-doped bovine serum albumin(BSA)derived carbon dots(BCDs)dubbed Eu-BCDs has been unveiled for ratiometric fluorescent detection of tetracycline(TC),which was formed from the one-step hydrothermal reaction of Eu^(3+)and BSA.Upon challenge with TC,the blue fluorescence of Eu-BCDs at 448 nm was gradually quenched due to the internal filtration effect,while the characteristic red fluorescence of Eu^(3+)at 618 nm was significantly enhanced owning to the antenna effect,leading to the ratiometric fluorescent detection of TC with fast response(2 min),a wide linear dynamic range(0-80μmol/L),and high selectivity and sensitivity(limit of detection(LOD)of 3 nmol/L).Moreover,Eu-BCDs can be successfully applied for the ratiometric fluorescent detection of TC in environmental and biological samples,such as river water,milk,honey and serum.The Eu-BCDs sensing platform would have great application potential in view of its simple preparation,rapid response,high sensitivity and good selectivity.
基金supported by National Key R&D Program of China (2018YFD0901103)National Natural Science Foundation of China (31901688)+2 种基金National Natural Science Foundation of China-Shandong Joint Fund for Marine Science Research Centers(U1606403)Natural Science Youth Foundation of Shandong Province(ZR2019QC004)Laboratory for Marine Drugs and Bioproducts of Pilot National Laboratory for Marine Science and Technology (Qingdao,LMDBKF201807).
文摘The intestine is the natural habitat for a large and dynamic bacterial community,which perform vital metabolic and immune functions that significantly effect the nutritional and health status of the host.The major physiological functions of intestinal flora include metabolic activities that lead to important trophic effects on immune structure and function as well as protection of the colonized host against invasion by transient microbes.The intestinal flora is both a target for nutritional intervention and a factor influencing the biological activity of food compounds acquired orally.Marine environments,as a source of diverse organic compounds,can supply us with a number of beneficial and health-promoting ingredients.This review focuses on the physiological functions of intestinal flora and reciprocal interactions between intestinal flora and dietary marine components including polysaccharides,lipids,protein,taurine,carotenoids,minerals,and polyphenols.This review can serve as a valuable reference regarding the consumption of seafood and marine nutraceuticals.
