The high porosity and tunable chemical functionality of metal-organic frameworks(MOFs)make it a promising catalyst design platform.High-throughput screening of catalytic performance is feasible since the large MOF str...The high porosity and tunable chemical functionality of metal-organic frameworks(MOFs)make it a promising catalyst design platform.High-throughput screening of catalytic performance is feasible since the large MOF structure database is available.In this study,we report a machine learning model for high-throughput screening of MOF catalysts for the CO_(2) cycloaddition reaction.The descriptors for model training were judiciously chosen according to the reaction mechanism,which leads to high accuracy up to 97%for the 75%quantile of the training set as the classification criterion.The feature contribution was further evaluated with SHAP and PDP analysis to provide a certain physical understanding.12,415 hypothetical MOF structures and 100 reported MOFs were evaluated under 100℃ and 1 bar within one day using the model,and 239 potentially efficient catalysts were discovered.Among them,MOF-76(Y)achieved the top performance experimentally among reported MOFs,in good agreement with the prediction.展开更多
Nanosized Ga-containing ZSM-5 zeolites were prepared via isomorphous substitution and impregnation followed by characterized using various techniques. The catalytic performance of the zeolites for the aromatization of...Nanosized Ga-containing ZSM-5 zeolites were prepared via isomorphous substitution and impregnation followed by characterized using various techniques. The catalytic performance of the zeolites for the aromatization of 1-hexene was investigated. The results indicate that isomorphous substitution promotes the incorporation of Ga heteroatoms into the framework along with the formation of extra-framework GaO;species（[GaO;]a） that have stronger interactions with the negative potential of the framework. In addition, based on the Py-IR results and catalytic performance, the [GaO;]aspecies with stronger Lewis acid sites produced a better synergism with moderate Br?nsted acid sites and thus improved the selectivity to aromatic compounds. However, the impregnation results in the formation of Ga;O;phase and small amounts of GaO;species that are mainly located on the external surface（[GaO;];）, which contribute to weaker Lewis acid sites due to weaker interactions with the zeolite framework. During 1-hexene aromatization, the nanosized Ga isomorphously substituted ZSM-5 zeolite samples（Gax-NZ5） exhibited better catalytic performance compared to the impregnated samples, and the highest aromatic yield（i.e.,65.4 wt%） was achieved over the Ga4.2-NZ5 sample, which contained with the highest Ga content.展开更多
Pinus densiflora var. zhangwuensis grows fast, and its drought and salinity resistance are better than Pinus sylvestris var. mongolica. We compared cold hardiness and mechanisms of cold hardiness between the two speci...Pinus densiflora var. zhangwuensis grows fast, and its drought and salinity resistance are better than Pinus sylvestris var. mongolica. We compared cold hardiness and mechanisms of cold hardiness between the two species, to provide a theoretical basis for promoting and applying P. densiflora var. zhangwuensis in cold regions. A cold stress experiment was carried out on 3-year-old plantlets of P. densiflora var. zhangwuensis and P. sylvestris var. mon- golica after hardening at five temperature regimes, 5, -10, -20, -40, and -60 ℃, respectively. Some indices of needle samples for both species were measured, such as relative conductivity （REL）, maximum photochemical efficiency （Fv/Fm）, malondialdehyde （MDA）, catalase （CAT）, proline （Pro）, soluble sugar （SS）, and stomata density. REL and MDA values of both species after hard- ening had the same trend of increasing, but the trend was opposite in Fv/Fm value with increasing cold stress. Com- pared with P. sylvestris var. mongolica, the P. densiflora var. zhangwuensis had smaller increases in REL and MDA, and a smaller decline in Fv/Fm during cold stress. Com- pared to the control, REL growth of P. densiflora var. zhangwuensis and P. sylvestris var. mongolica at -60 ℃were 0.41 and 0.60, and MDA growth was 29.94 mol g-1 FW and 47.80 mol g-1 FW, and Fv/Fm declines were 0.08 and 0.27. Half-lethal temperatures （LT50） calculated by logistic equation for P. densiflora var. zhangwuensis and P. sylvestris var. mongolica were -58.23 and -50.34 ℃, respectively. These data suggest that cold resistance of P. densiflora var. zhangwuensis is stronger than that of P. sylvestris var. mongolica. Cold-resistance mechanisms of the two species differed. In response to cold stress, P. sylvestris var. mongolica had strong osmotic adjustment ability because of higher Pro and SS content, while P. densiflora var. zhangwuensis had strong antioxidant ability due to stronger CAT activity. Stomata density and diameter of P. densiflora var. zhangwuensis were smaller, as were single leaf area and number of leaves per plant, both characteristics promoting survival in a cold environment. Greater shoot height and total biomass of seedlings of P. densiflora var. zhangwuensis might be another reason for its stronger cold tolerance.展开更多
With the improvement of people's living standards, gastrointestinal adverse reactions caused by various adverse factors have attracted more and more people's attention. A recent study has indicated that corona...With the improvement of people's living standards, gastrointestinal adverse reactions caused by various adverse factors have attracted more and more people's attention. A recent study has indicated that coronavirus disease 2019(COVID-19) could also invade the gastrointestinal tract, leading to gastrointestinal adverse reactions(Song et al., 2020). In recent years, immunotherapy has provided certain effects for some patients with advanced malignant tumors.展开更多
With changes in global climate and land use,the area of desertified farmland in southeastern Horqin Sandy Land(HSL)has increased in recent years,and farmlands are being abandoned.These abandoned farmlands(AFs)nega-tiv...With changes in global climate and land use,the area of desertified farmland in southeastern Horqin Sandy Land(HSL)has increased in recent years,and farmlands are being abandoned.These abandoned farmlands(AFs)nega-tively impact the local ecology.Therefore,the aim of the present study was to select suitable trees and shrubs for those AFs to prevent and control the desertification tendency.In this study,three AFs were fenced for 2 years,then 37 arbor and shrub species or varieties of 21 families were planted in the fenced AFs and grown for 10 years.The ecological adaptability of the species was evaluated and ranked using a principal component analysis.The results showed that the biodiversity of the AFs significantly improved after 2 years of fencing;the Shannon-Wiener index and species rich-ness of perennial grasses and forbs were 1.45 and 3.6 times higher,respectively,than for the unfenced AF.Among all species planted in fenced AFs,nine tree species had posi-tive comprehensive F(CF)values;Pinus sylvestris(Russian Shira steppe provenance),Populus alba‘Berolinensis’and Gleditsia triacanthos had CF greater than 1,and the first(PC1),second(PC2)and third(PC3)principal component values(F_(1),F_(2),F_(3))were all positive.Among the shrubs,only Lespedeza bicolor and Rosa xanthina f.normalis had CF greater than 0.All these results suggest that fencing improves biodiversity and that planting trees and shrubs that have higher CF values on the basis of fencing is an effective way to green and beautify AFs in HSL.展开更多
0 INTRODUCTION Continental shale oil is a strategic alternative resource to ensure the safety of national oil supply and improve the level of industrial innovation.China is a large country of continental oil resources...0 INTRODUCTION Continental shale oil is a strategic alternative resource to ensure the safety of national oil supply and improve the level of industrial innovation.China is a large country of continental oil resources,accounting for 90%of the total onshore oil resources;and China is also a major producer of continental oil,accounting for about 93%of the total oil production(Yang et al.,2019;Jia et al.,2018).展开更多
OBJECTIVE To determine the quantity and quality of liver NK cells from young and adult mice and compare their characteristics. METHODS C57BL/6 mice were used at 2 weeks （young） and 8 weeks （adult） of age. The perc...OBJECTIVE To determine the quantity and quality of liver NK cells from young and adult mice and compare their characteristics. METHODS C57BL/6 mice were used at 2 weeks （young） and 8 weeks （adult） of age. The percentage and absolute number of NK cells in the liver and spleen were analyzed. The cytotoxicity of NK cells in the liver and spleen against various targets were detected by a 4 h ^51Cr-release method. FACScan was used to analyze the expression of CD69, Mac-l1 Ly49C/I and CD94 on the NK cells. Perforin mRNA levels were analyzed by the reverse transcription polymerase chain reaction （RT-PCR）. RESUTLS The percentages of NK cells in the liver of young and adult mice were similar （11.9%＋1.7% vs. 9.9%＋1.6%, P〉0.05）, but the absolute number per liver weight was higher in the young animals （11.6＋2.5×10^5/g vs. 3.4＋0.8×10^5/g, P〈0.05）. The level of NK cytotoxicity was extremely high in the liver of young compared to adult mice （71.0%＋5.5% vs. 23.8%＋4.4%, P〈0.05）, but this difference was not observed in the spleen. Phenotypes of the liver NK cells from young and adult mice were completely different from each other. The liver NK cells from young mice were CD69^high Mac-1^low Ly49C/ I^low, whereas NK cells from older mice displayed inverse antigen levels （CD- 69^low Mac-1^high Ly49C/I^high）. The expression levels of other NK cell-related markers were similar in both groups.The perforin mRNA level in the liver lymphocytes from young mice was consistently greater compared to adult mice. CONCLUSION From 2 to 8 weeks C57BU6 mice liver NK cells undergo age-associated changes. At 2 weeks of age the liver NK cells showed a high level of NK cytotoxicity and a unique phenotype which was not apparent at 8 weeks of age.展开更多
Separating/capturing SF_(6),having the strongest global warming potential,from exhaust gas with low concentration(1%–10%)in the power industry is significant for both greenhouse gas emission control and SF_(6) recycl...Separating/capturing SF_(6),having the strongest global warming potential,from exhaust gas with low concentration(1%–10%)in the power industry is significant for both greenhouse gas emission control and SF_(6) recycling and reutilization.In this study,we achieved highly efficient SF_(6)/N_(2) separation under different SF_(6) concentrations(1% and 10%)using two homologous metal-organic frameworks,Ni-bpz and Zn-bpz.This outcome underscores the effectiveness of rational nano-traps distribution engineering for targeted separation applications.The molecular simulation suggests that an SF_(6) molecule interacts with a single nano-trap in Zn-bpz.At the same time,it is efficiently confined by two adjacent nano-traps in the parallel distribution of Ni-bpz.Consequently,exceptional SF_(6)/N_(2) selectivity for 1/99 and 10/90 mixtures have been respectively achieved in Ni-bpz(516,SF_(6)/N_(2)=1/99)and Zn-bpz(608,SF_(6)/N_(2)=10/90)at 298 K and 1 bar.In dynamic breakthrough experiments,Ni-bpz exhibits a record pure N_(2)(≥99.99%)productivity(1496 mL/g)for an SF_(6)/N_(2)(1/99)gas mixture.Moreover,both MOFs demonstrate excellent water resistance across multiple cycles,suggesting their high promise for practical application.展开更多
Methane(CH_(4)),as the primary component of natural gas,has the highest hydrogen-to-carbon ratio,making it a clean energy source[1].In contrast to high-concentration methane source derived from oil extraction,low-grad...Methane(CH_(4)),as the primary component of natural gas,has the highest hydrogen-to-carbon ratio,making it a clean energy source[1].In contrast to high-concentration methane source derived from oil extraction,low-grade coal-bed methane(CBM,<30%,predominantly mixed with N_(2)),is difficult to be used directly and often is released into the atmosphere during coal mining for safety reasons[2].The methane emission not only wastes a cleaner energy source but also contributes to global warming,as methane ranks as the second most significant greenhouse gas[3].展开更多
Gene overlap serves as a common strategy employed by bacteria and viruses to expand their genomic capacity.Over the past two decades,advances in omics studies have unveiled a prevalence of overlapped genes in eukaryot...Gene overlap serves as a common strategy employed by bacteria and viruses to expand their genomic capacity.Over the past two decades,advances in omics studies have unveiled a prevalence of overlapped genes in eukaryotes,including mammals.However,few are reported to participate in the regulation of the cardiovascular system.展开更多
The hydroisomerization of n-hexadecane over Pt-Pd bimetallic catalysts is an effective way to produce clean fuel oil.This work reports a useful preparation method of bimetallic bifunctional catalysts by a co-impregnat...The hydroisomerization of n-hexadecane over Pt-Pd bimetallic catalysts is an effective way to produce clean fuel oil.This work reports a useful preparation method of bimetallic bifunctional catalysts by a co-impregnation or sequential impregnation process.Furthermore,monometallic catalysts with loading either Pt or Pd are also prepared for comparison.The effects of the metal species and impregnation order on the characteristics and catalytic performance of the catalysts are investigated.The catalytic test results indicate that the maximum iso-hexadecane yield over different catalysts increases as follows:Pt/silicoaluminophosphate SAPO-41<Pd/SAPO-41<Pt^(*)-Pd/SAPO-41(prepared by sequential impregnation)<Pt-Pd/SAPO-41(prepared by co-impregnation).Owing to the synergic effects between Pt and Pd,the Pt-Pd/SAPO-41 catalyst prepared by the co-impregnation method demonstrates the effective promotion of(de)hydrogenation activity.Therefore,this catalyst exhibits the highest iso-hexadecane yield of 89.4%when the n-hexadecane conversion is 96.3%.Additionally,the Pt-Pd/SAPO-41 catalyst also presents the highest catalytic activity and best stability even after 150 h long-term tests.展开更多
Organic matter is the basis for oil and gas generation,and the depositional environment controls its enrichment.The first member of the Qingshankou Formation(K_(2)qn^(1))in Songliao Basin has a thick organic-rich shal...Organic matter is the basis for oil and gas generation,and the depositional environment controls its enrichment.The first member of the Qingshankou Formation(K_(2)qn^(1))in Songliao Basin has a thick organic-rich shale and so is an important target section for shale oil exploration and development.In the Gulong Sag,shale samples from this unit were collected over the full length of the section.The characterization of the environments of deposition(EOD)of K_(2)qn^(1)was improved by utilizing lithological characteristics,thin section observations,elemental compositions,and organic carbon concentrations.Combined with the normalization coefficients proposed in this paper,an organic matter correlation model was established to elucidate the factors that influence organic matter enrichment.From the bottom to the top of K2qn1,the lake depth gradually becomes shallower,the primary productivity first decreases and then increases,the reducing conditions become stronger and then weaker,the water salinity gradually decreases,the climate first becomes semi-humid and then warm and humid,and the input of terrigenous debris first decreases and then increases.A major marine transgression at the base of the K_(2)qn^(1)᾽s brought in nutrients to increase primary productivity,and the density-stratified reducing environment preserved and enriched organic matter.High primary productivity occurred during the middle of the deposition of the K_(2)qn^(1),while terrigenous input is low.Organic matter is preserved in reduced deep lake environments,resulting in organic matter-rich black shale.The lake became shallower,and the salinity decreased in the upper part of K_(2)qn^(1).Benthic organisms rapidly multiplied,consuming large amounts of oxygen and destroying the previously depositional environment,resulting in a reducing environment disturbed by benthic organisms with poor preservation conditions and the lowest organic matter content.展开更多
miR-18a has been identified as a significantly expressed microRNA(miRNA)in non-small cell lung cancer(NSCLC)and plays a vital role in cancer cell transformation,metastasis,and carcinogenesis.Herein,a pair of binary pr...miR-18a has been identified as a significantly expressed microRNA(miRNA)in non-small cell lung cancer(NSCLC)and plays a vital role in cancer cell transformation,metastasis,and carcinogenesis.Herein,a pair of binary probes from numerous probe pairs based on single nucleotide polymorphism analyses of miR-18a and miR-18b was first designed and screened to develop a Y-shaped ratio biosensor for accurate detection of serum miR-18a in NSCLC.The special structure of the binary probes combined with the hairpin showed strong specificity for miR-18a,which was confirmed by polyacrylamide gel electrophoresis assay and square wave voltammetry assay.Furthermore,it is beneficial to immobilize single-stranded DNA(ssDNA)probes due to the large specific surface area of nanoporous gold,thereby improving the sensitivity of the biosensor.The Y-shaped ratio biosensor exhibited a wide detection range and can quantify the concentration of miR-18a in the range of 10 fmol/L–100 pmol/L,with a limit of detection of 0.211 fmol/L(S/N=3).Moreover,it exhibits excellent detection capabilities in serum samples since the biosensor showed a high selectivity toward the coexistence of miR-18a and miR-18b.Therefore,the prepared Y-shaped ratio biosensor is a highly sensitive and specific miR-18a detection tool,capable of identifying microscopic amounts of miR-18a in serum samples,providing great potential for early screening of NSCLC.展开更多
基金financial support from the National Key Research and Development Program of China(2021YFB 3501501)the National Natural Science Foundation of China(No.22225803,22038001,22108007 and 22278011)+1 种基金Beijing Natural Science Foundation(No.Z230023)Beijing Science and Technology Commission(No.Z211100004321001).
文摘The high porosity and tunable chemical functionality of metal-organic frameworks(MOFs)make it a promising catalyst design platform.High-throughput screening of catalytic performance is feasible since the large MOF structure database is available.In this study,we report a machine learning model for high-throughput screening of MOF catalysts for the CO_(2) cycloaddition reaction.The descriptors for model training were judiciously chosen according to the reaction mechanism,which leads to high accuracy up to 97%for the 75%quantile of the training set as the classification criterion.The feature contribution was further evaluated with SHAP and PDP analysis to provide a certain physical understanding.12,415 hypothetical MOF structures and 100 reported MOFs were evaluated under 100℃ and 1 bar within one day using the model,and 239 potentially efficient catalysts were discovered.Among them,MOF-76(Y)achieved the top performance experimentally among reported MOFs,in good agreement with the prediction.
基金supported by the National Natural Science Foundation of China(Nos.21276067 and 21676074)Programs of International S&T cooperation(No.2014DFR41110)
文摘Nanosized Ga-containing ZSM-5 zeolites were prepared via isomorphous substitution and impregnation followed by characterized using various techniques. The catalytic performance of the zeolites for the aromatization of 1-hexene was investigated. The results indicate that isomorphous substitution promotes the incorporation of Ga heteroatoms into the framework along with the formation of extra-framework GaO;species（[GaO;]a） that have stronger interactions with the negative potential of the framework. In addition, based on the Py-IR results and catalytic performance, the [GaO;]aspecies with stronger Lewis acid sites produced a better synergism with moderate Br?nsted acid sites and thus improved the selectivity to aromatic compounds. However, the impregnation results in the formation of Ga;O;phase and small amounts of GaO;species that are mainly located on the external surface（[GaO;];）, which contribute to weaker Lewis acid sites due to weaker interactions with the zeolite framework. During 1-hexene aromatization, the nanosized Ga isomorphously substituted ZSM-5 zeolite samples（Gax-NZ5） exhibited better catalytic performance compared to the impregnated samples, and the highest aromatic yield（i.e.,65.4 wt%） was achieved over the Ga4.2-NZ5 sample, which contained with the highest Ga content.
基金supported by the National Forestry Public Welfare Industry Research Project(201004023)Liaoning Agricultural Science and Technology Key Project(2011207002 and2011207004)
文摘Pinus densiflora var. zhangwuensis grows fast, and its drought and salinity resistance are better than Pinus sylvestris var. mongolica. We compared cold hardiness and mechanisms of cold hardiness between the two species, to provide a theoretical basis for promoting and applying P. densiflora var. zhangwuensis in cold regions. A cold stress experiment was carried out on 3-year-old plantlets of P. densiflora var. zhangwuensis and P. sylvestris var. mon- golica after hardening at five temperature regimes, 5, -10, -20, -40, and -60 ℃, respectively. Some indices of needle samples for both species were measured, such as relative conductivity （REL）, maximum photochemical efficiency （Fv/Fm）, malondialdehyde （MDA）, catalase （CAT）, proline （Pro）, soluble sugar （SS）, and stomata density. REL and MDA values of both species after hard- ening had the same trend of increasing, but the trend was opposite in Fv/Fm value with increasing cold stress. Com- pared with P. sylvestris var. mongolica, the P. densiflora var. zhangwuensis had smaller increases in REL and MDA, and a smaller decline in Fv/Fm during cold stress. Com- pared to the control, REL growth of P. densiflora var. zhangwuensis and P. sylvestris var. mongolica at -60 ℃were 0.41 and 0.60, and MDA growth was 29.94 mol g-1 FW and 47.80 mol g-1 FW, and Fv/Fm declines were 0.08 and 0.27. Half-lethal temperatures （LT50） calculated by logistic equation for P. densiflora var. zhangwuensis and P. sylvestris var. mongolica were -58.23 and -50.34 ℃, respectively. These data suggest that cold resistance of P. densiflora var. zhangwuensis is stronger than that of P. sylvestris var. mongolica. Cold-resistance mechanisms of the two species differed. In response to cold stress, P. sylvestris var. mongolica had strong osmotic adjustment ability because of higher Pro and SS content, while P. densiflora var. zhangwuensis had strong antioxidant ability due to stronger CAT activity. Stomata density and diameter of P. densiflora var. zhangwuensis were smaller, as were single leaf area and number of leaves per plant, both characteristics promoting survival in a cold environment. Greater shoot height and total biomass of seedlings of P. densiflora var. zhangwuensis might be another reason for its stronger cold tolerance.
文摘With the improvement of people's living standards, gastrointestinal adverse reactions caused by various adverse factors have attracted more and more people's attention. A recent study has indicated that coronavirus disease 2019(COVID-19) could also invade the gastrointestinal tract, leading to gastrointestinal adverse reactions(Song et al., 2020). In recent years, immunotherapy has provided certain effects for some patients with advanced malignant tumors.
基金This study was supported by National Natural Science Foundation of China(31770675)National Key R&D Program of China(2017YFD0600505).
文摘With changes in global climate and land use,the area of desertified farmland in southeastern Horqin Sandy Land(HSL)has increased in recent years,and farmlands are being abandoned.These abandoned farmlands(AFs)nega-tively impact the local ecology.Therefore,the aim of the present study was to select suitable trees and shrubs for those AFs to prevent and control the desertification tendency.In this study,three AFs were fenced for 2 years,then 37 arbor and shrub species or varieties of 21 families were planted in the fenced AFs and grown for 10 years.The ecological adaptability of the species was evaluated and ranked using a principal component analysis.The results showed that the biodiversity of the AFs significantly improved after 2 years of fencing;the Shannon-Wiener index and species rich-ness of perennial grasses and forbs were 1.45 and 3.6 times higher,respectively,than for the unfenced AF.Among all species planted in fenced AFs,nine tree species had posi-tive comprehensive F(CF)values;Pinus sylvestris(Russian Shira steppe provenance),Populus alba‘Berolinensis’and Gleditsia triacanthos had CF greater than 1,and the first(PC1),second(PC2)and third(PC3)principal component values(F_(1),F_(2),F_(3))were all positive.Among the shrubs,only Lespedeza bicolor and Rosa xanthina f.normalis had CF greater than 0.All these results suggest that fencing improves biodiversity and that planting trees and shrubs that have higher CF values on the basis of fencing is an effective way to green and beautify AFs in HSL.
基金PetroChina Shale Oil Major Science and Technology Project(No.2021DJ18)the National High-Level Special Talent Support Plan(the fourth batch)。
文摘0 INTRODUCTION Continental shale oil is a strategic alternative resource to ensure the safety of national oil supply and improve the level of industrial innovation.China is a large country of continental oil resources,accounting for 90%of the total onshore oil resources;and China is also a major producer of continental oil,accounting for about 93%of the total oil production(Yang et al.,2019;Jia et al.,2018).
文摘OBJECTIVE To determine the quantity and quality of liver NK cells from young and adult mice and compare their characteristics. METHODS C57BL/6 mice were used at 2 weeks （young） and 8 weeks （adult） of age. The percentage and absolute number of NK cells in the liver and spleen were analyzed. The cytotoxicity of NK cells in the liver and spleen against various targets were detected by a 4 h ^51Cr-release method. FACScan was used to analyze the expression of CD69, Mac-l1 Ly49C/I and CD94 on the NK cells. Perforin mRNA levels were analyzed by the reverse transcription polymerase chain reaction （RT-PCR）. RESUTLS The percentages of NK cells in the liver of young and adult mice were similar （11.9%＋1.7% vs. 9.9%＋1.6%, P〉0.05）, but the absolute number per liver weight was higher in the young animals （11.6＋2.5×10^5/g vs. 3.4＋0.8×10^5/g, P〈0.05）. The level of NK cytotoxicity was extremely high in the liver of young compared to adult mice （71.0%＋5.5% vs. 23.8%＋4.4%, P〈0.05）, but this difference was not observed in the spleen. Phenotypes of the liver NK cells from young and adult mice were completely different from each other. The liver NK cells from young mice were CD69^high Mac-1^low Ly49C/ I^low, whereas NK cells from older mice displayed inverse antigen levels （CD- 69^low Mac-1^high Ly49C/I^high）. The expression levels of other NK cell-related markers were similar in both groups.The perforin mRNA level in the liver lymphocytes from young mice was consistently greater compared to adult mice. CONCLUSION From 2 to 8 weeks C57BU6 mice liver NK cells undergo age-associated changes. At 2 weeks of age the liver NK cells showed a high level of NK cytotoxicity and a unique phenotype which was not apparent at 8 weeks of age.
基金the financial support from the National Natural Science Foundation of China(Nos.22225803,22038001,22278011,and 22108007)the Beijing Natural Science Foundation(No.Z230023)the Beijing Nova Program(No.Z211100002121094).
文摘Separating/capturing SF_(6),having the strongest global warming potential,from exhaust gas with low concentration(1%–10%)in the power industry is significant for both greenhouse gas emission control and SF_(6) recycling and reutilization.In this study,we achieved highly efficient SF_(6)/N_(2) separation under different SF_(6) concentrations(1% and 10%)using two homologous metal-organic frameworks,Ni-bpz and Zn-bpz.This outcome underscores the effectiveness of rational nano-traps distribution engineering for targeted separation applications.The molecular simulation suggests that an SF_(6) molecule interacts with a single nano-trap in Zn-bpz.At the same time,it is efficiently confined by two adjacent nano-traps in the parallel distribution of Ni-bpz.Consequently,exceptional SF_(6)/N_(2) selectivity for 1/99 and 10/90 mixtures have been respectively achieved in Ni-bpz(516,SF_(6)/N_(2)=1/99)and Zn-bpz(608,SF_(6)/N_(2)=10/90)at 298 K and 1 bar.In dynamic breakthrough experiments,Ni-bpz exhibits a record pure N_(2)(≥99.99%)productivity(1496 mL/g)for an SF_(6)/N_(2)(1/99)gas mixture.Moreover,both MOFs demonstrate excellent water resistance across multiple cycles,suggesting their high promise for practical application.
基金supported by the National Natural Science Foundation of China(22225803,22038001,22278011,and 22108007)the Beijing Natural Science Foundation(Z230023)the Beijing Nova Program(Z211100002121094).
文摘Methane(CH_(4)),as the primary component of natural gas,has the highest hydrogen-to-carbon ratio,making it a clean energy source[1].In contrast to high-concentration methane source derived from oil extraction,low-grade coal-bed methane(CBM,<30%,predominantly mixed with N_(2)),is difficult to be used directly and often is released into the atmosphere during coal mining for safety reasons[2].The methane emission not only wastes a cleaner energy source but also contributes to global warming,as methane ranks as the second most significant greenhouse gas[3].
基金supported by a British Heart Foundation PhD studentshipFS-15-74-31669 (to L.Z.)projectgrantPG/22/11055 (to M.Z.)partially supported by the China Scholarship Council。
文摘Gene overlap serves as a common strategy employed by bacteria and viruses to expand their genomic capacity.Over the past two decades,advances in omics studies have unveiled a prevalence of overlapped genes in eukaryotes,including mammals.However,few are reported to participate in the regulation of the cardiovascular system.
基金the financial supports from the National Key R&D Program of China,Intergovernmental International Science and Technology Innovation Cooperation Key Project(Grant No.2018YFE0108800)the National Natural Science Foundation of China(Grant Nos.21676074 and 21706053)National Key Research and Development Project,National Ministry of Education“Silk Road 1+1”Research Cooperation Project.
文摘The hydroisomerization of n-hexadecane over Pt-Pd bimetallic catalysts is an effective way to produce clean fuel oil.This work reports a useful preparation method of bimetallic bifunctional catalysts by a co-impregnation or sequential impregnation process.Furthermore,monometallic catalysts with loading either Pt or Pd are also prepared for comparison.The effects of the metal species and impregnation order on the characteristics and catalytic performance of the catalysts are investigated.The catalytic test results indicate that the maximum iso-hexadecane yield over different catalysts increases as follows:Pt/silicoaluminophosphate SAPO-41<Pd/SAPO-41<Pt^(*)-Pd/SAPO-41(prepared by sequential impregnation)<Pt-Pd/SAPO-41(prepared by co-impregnation).Owing to the synergic effects between Pt and Pd,the Pt-Pd/SAPO-41 catalyst prepared by the co-impregnation method demonstrates the effective promotion of(de)hydrogenation activity.Therefore,this catalyst exhibits the highest iso-hexadecane yield of 89.4%when the n-hexadecane conversion is 96.3%.Additionally,the Pt-Pd/SAPO-41 catalyst also presents the highest catalytic activity and best stability even after 150 h long-term tests.
基金funded by the National Natural Science Foundation of China(Grant Nos.42072147 and 41922015)the Fundamental Research Funds for the Central Universities(No.22CX07001A).
文摘Organic matter is the basis for oil and gas generation,and the depositional environment controls its enrichment.The first member of the Qingshankou Formation(K_(2)qn^(1))in Songliao Basin has a thick organic-rich shale and so is an important target section for shale oil exploration and development.In the Gulong Sag,shale samples from this unit were collected over the full length of the section.The characterization of the environments of deposition(EOD)of K_(2)qn^(1)was improved by utilizing lithological characteristics,thin section observations,elemental compositions,and organic carbon concentrations.Combined with the normalization coefficients proposed in this paper,an organic matter correlation model was established to elucidate the factors that influence organic matter enrichment.From the bottom to the top of K2qn1,the lake depth gradually becomes shallower,the primary productivity first decreases and then increases,the reducing conditions become stronger and then weaker,the water salinity gradually decreases,the climate first becomes semi-humid and then warm and humid,and the input of terrigenous debris first decreases and then increases.A major marine transgression at the base of the K_(2)qn^(1)᾽s brought in nutrients to increase primary productivity,and the density-stratified reducing environment preserved and enriched organic matter.High primary productivity occurred during the middle of the deposition of the K_(2)qn^(1),while terrigenous input is low.Organic matter is preserved in reduced deep lake environments,resulting in organic matter-rich black shale.The lake became shallower,and the salinity decreased in the upper part of K_(2)qn^(1).Benthic organisms rapidly multiplied,consuming large amounts of oxygen and destroying the previously depositional environment,resulting in a reducing environment disturbed by benthic organisms with poor preservation conditions and the lowest organic matter content.
基金supported by the Science and Technology Development FundMacao SAR(0040/2021/AGJ)。
文摘miR-18a has been identified as a significantly expressed microRNA(miRNA)in non-small cell lung cancer(NSCLC)and plays a vital role in cancer cell transformation,metastasis,and carcinogenesis.Herein,a pair of binary probes from numerous probe pairs based on single nucleotide polymorphism analyses of miR-18a and miR-18b was first designed and screened to develop a Y-shaped ratio biosensor for accurate detection of serum miR-18a in NSCLC.The special structure of the binary probes combined with the hairpin showed strong specificity for miR-18a,which was confirmed by polyacrylamide gel electrophoresis assay and square wave voltammetry assay.Furthermore,it is beneficial to immobilize single-stranded DNA(ssDNA)probes due to the large specific surface area of nanoporous gold,thereby improving the sensitivity of the biosensor.The Y-shaped ratio biosensor exhibited a wide detection range and can quantify the concentration of miR-18a in the range of 10 fmol/L–100 pmol/L,with a limit of detection of 0.211 fmol/L(S/N=3).Moreover,it exhibits excellent detection capabilities in serum samples since the biosensor showed a high selectivity toward the coexistence of miR-18a and miR-18b.Therefore,the prepared Y-shaped ratio biosensor is a highly sensitive and specific miR-18a detection tool,capable of identifying microscopic amounts of miR-18a in serum samples,providing great potential for early screening of NSCLC.
