Inverse Synthetic Aperture Radar (ISAR) is an important means for target classification, recognition, identification and many other military applications. A simulation model of ISAR system is established after analyzi...Inverse Synthetic Aperture Radar (ISAR) is an important means for target classification, recognition, identification and many other military applications. A simulation model of ISAR system is established after analyzing the principle of ISAR imaging, and then several ECM (Electronic Counter Measurement) techniques are studied. Simulation experiments are done on the basis of such research. The experimental result of the research can be used for ECM equipment.展开更多
A wire-mesh catalyst coated by La0.8Sr0.2MnO3 was combined with a dielectric barrier discharge （DBD） reactor for toluene removal at atmospheric pressure. It was found that toluene removal efficiency and carbon dioxi...A wire-mesh catalyst coated by La0.8Sr0.2MnO3 was combined with a dielectric barrier discharge （DBD） reactor for toluene removal at atmospheric pressure. It was found that toluene removal efficiency and carbon dioxide selectivity were enhanced in the catalytic packed-bed reactor. In addition, ozone and nitrogen monoxide from the gas effluent byproducts decreased. This is the first time that ultrasound combined with plasma has been used for toluene removal. A synergistic effect on toluene removal was observed in the plasma-assisted ultrasound system. At the same time, the system increased toluene conversion and reduced ozone emission.展开更多
The binary polyhydrides of heavy rare earth lutetium that shares a similar valence electron configuration to lanthanum have been experimentally discovered to be superconductive.The lutetium polyhydrides were successfu...The binary polyhydrides of heavy rare earth lutetium that shares a similar valence electron configuration to lanthanum have been experimentally discovered to be superconductive.The lutetium polyhydrides were successfully synthesized at high pressure and high temperature conditions using a diamond anvil cell in combinations with the in-situ high pressure laser heating technique.The resistance measurements as a function of temperature were performed at the same pressure of synthesis in order to study the transitions of superconductivity(SC).The superconducting transition with a maximum onset temperature(Tc)71 K was observed at pressure of 218 GPa in the experiments.The Tcdecreased to 65 K when pressure was at 181 GPa.From the evolution of SC at applied magnetic fields,the upper critical field at zero temperatureμ0Hc2(0)was obtained to be~36 T.The in-situ high pressure X-ray diffraction experiments imply that the high TcSC should arise from the Lu4H23phase with Pm3n symmetry that forms a new type of hydrogen cage framework different from those reported for previous light rare earth polyhydride superconductors.展开更多
Studies have shown that targeting xanthine oxidase(XO)can be a feasible treatment for fructose-induced hyperuricemia and hyperglycemia.This study aimed to evaluate the dual regulatory effects and molecular mechanisms ...Studies have shown that targeting xanthine oxidase(XO)can be a feasible treatment for fructose-induced hyperuricemia and hyperglycemia.This study aimed to evaluate the dual regulatory effects and molecular mechanisms of diacylated anthocyanins from purple sweet potato(diacylated AF-PSPs)on hyperglycemia and hyperuricemia induced by a high-fructose/high-fat diet.The body weight,organ index,serum biochemical indexes,and liver antioxidant indexes of mice were measured,and the kidneys were observed in pathological sections.The relative expression levels of messenger RNAs(mRNAs)of fructose metabolism pathway enzymes in kidney were detected by fluorescent real-time quantitative polymerase chain(qPCR)reaction technique,and the expression of renal transporter protein and inflammatory factor pathway protein was determined by immunohistochemistry(IHC)technique.Results showed that diacylated AF-PSPs alleviated hyperuricemia in mice,and that this effect might be related to the regulation of liver XO activity,lipid accumulation,and relevant renal transporters.Diacylated AF-PSPs reduced body weight and relieved lipid metabolism disorder,liver lipid accumulation,and liver oxidative stress,thereby enhancing insulin utilization and sensitivity,lowering blood sugar,and reducing hyperglycemia in mice.Also,diacylated AF-PSPs restored mRNA levels related to renal fructose metabolism,and reduced kidney injury and inflammation.This study provided experimental evidence for the mechanisms of dual regulation of blood glucose and uric acid(UA)by diacylated AF-PSPs and their utilization as functional foods in the management of metabolic syndrome.展开更多
A azoreductase gene with 537 bp was obtained by PCR amplification from Rhodobacter sphaeroides AS1 1737 The enzyme, with a molecular weight of 18 7 kD, was efficiently expressed in Escherichia coli and its biodegr...A azoreductase gene with 537 bp was obtained by PCR amplification from Rhodobacter sphaeroides AS1 1737 The enzyme, with a molecular weight of 18 7 kD, was efficiently expressed in Escherichia coli and its biodegradation characteristics for azo dyes were investigated. Furthermore, the reaction kinetics and mechanism of azo dyes catalyzed by the genetically engineered azoreductase were studied in detail. The presence of a hydrazo-intermediate was identified, which provided a convincing evidence for the assumption that azo dyes were degraded via an incomplete reduction stage.展开更多
Background:Coronavirus disease 2019(COVID-19)has potential risks for both clinically worsening pulmonary hypertension(PH)and increasing mortality.However,the data regarding the protective role of vaccination in this p...Background:Coronavirus disease 2019(COVID-19)has potential risks for both clinically worsening pulmonary hypertension(PH)and increasing mortality.However,the data regarding the protective role of vaccination in this population are still lacking.This study aimed to assess the safety of approved vaccination for patients with PH.Methods:In this national prospective cohort study,patients diagnosed with PH(World Health Organization[WHO]groups 1 and 4)were enrolled from October 2021 to April 2022.The primary outcome was the composite of PH-related major adverse events.We used an inverse probability weighting(IPW)approach to control for possible confounding factors in the baseline characteristics of patients.Results:In total,706 patients with PH participated in this study(mean age,40.3 years;mean duration after diagnosis of PH,8.2 years).All patients received standardized treatment for PH in accordance with guidelines for the diagnosis and treatment of PH in China.Among them,278 patients did not receive vaccination,whereas 428 patients completed the vaccination series.None of the participants were infected with COVID-19 during our study period.Overall,398 patients received inactivated severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)vaccine,whereas 30 received recombinant protein subunit vaccine.After adjusting for baseline covariates using the IPW approach,the odds of any adverse events due to PH in the vaccinated group did not statistically significantly increase(27/428[6.3%]vs.24/278[8.6%],odds ratio=0.72,P=0.302).Approximately half of the vaccinated patients reported at least one post-vaccination side effects,most of which were mild,including pain at the injection site(159/428,37.1%),fever(11/428,2.6%),and fatigue(26/428,6.1%).Conclusions:COVID-19 vaccination did not significantly augment the PH-related major adverse events for patients with WHO groups 1 and 4 PH,although there were some tolerable side effects.A large-scale randomized controlled trial is warranted to confirm this finding.The final approval展开更多
With a production of 208.2 m3/d, heavy oil was produced by drill stem test (DST) from three shallow reservoirs in Sand Group Nos. Ⅰ and Ⅲ of the Neogene Guantao Formation (NgⅠ and NgⅢ) and the Eogene Dongying Form...With a production of 208.2 m3/d, heavy oil was produced by drill stem test (DST) from three shallow reservoirs in Sand Group Nos. Ⅰ and Ⅲ of the Neogene Guantao Formation (NgⅠ and NgⅢ) and the Eogene Dongying Formation (Ed) in an exploratory well Ban-14-1 within the Qianmiqiao region, Bohai Bay Basin, northern China. Based on the GC and GC-MS data of the NgⅠ and NgⅢ heavy oil samples, all n-alkanes and most isoprenoid hydrocarbons are lost and the GC baseline appears as an evident 'hump', implying a large quantity of unresolved complex mixture (UCM), which typically revealed a result of heavy biodegradation. However, there still is a complete series of C14-C73 n-alkanes in the high-temperature gas chromatograms (HTGC) of the heavy oil, among which, the abundance of C30- n-alkanes are drastically reduced. The C35-C55 high molecular weight (HMW) n-alkanes are at high abundance and show a normal distribution pattern with major peak at C43 and an obvious odd-carbon-number predominance with CPI37-55 and OEP45-49 values of 1.17 and 1.16-1.20, respectively. According to GC-MS analysis, the heavy oil is characterized by dual source inputs of aquatic microbes and terrestrial higher plants. Various steranes and tricyclic terpanes indicate an algal origin, and hopane-type triterpanes, C24 tetracyclic terpane and drimane series show the bacterial contribution. With the odd-carbon-number preference, HMW n-alkanes provide significant information not only on higher plant source input and immaturity, but also on the strong resistibility to biodegradation.展开更多
Aims Shrub encroachment has taken place in many of China’s northern grasslands.This study attempts to answer the following questions:which plant communities are present in these shrub-encroached grasslands(SEGs)?What...Aims Shrub encroachment has taken place in many of China’s northern grasslands.This study attempts to answer the following questions:which plant communities are present in these shrub-encroached grasslands(SEGs)?What are the species richness and composition of these communities?Which environmental factors determine the spatial distribution thereof?Methods We investigated the community characteristics of 255 SEG plots with a size of 20 m×20 m at 69 locations across grasslands in northern China.In each plot,paired 1-m^(2) quadrats were estab-lished within shrub patches and the neighbouring grassy matrix to record herb species composition.The quantitative character-istics(abundance,coverage and height)of herbs were meas-ured in 0.25-m2 subquadrats,and soil samples were collected in the quadrats.Two-way indicator species analysis(TWINSPAN),detrended canonical analysis(DCA)and canonical correspond-ence analysis(CCA)were used for community clustering and ordination.Important Findings The DCA and TWINSPAN results suggested that the SEGs in northern China can be divided into six community types:Potentilla fruticosa+Carex atrofusca,Spiraea hypericifolia+Festuca ovina,Caragana acanthophylla+Stipa sareptana,Caragana microphylla+Leymus chinensis,Caragana microphylla+Stipa klemenzii and Caragana tibetica+Cleistogenes songorica.At a regional scale,climate and soil nutrients controlled the spatial patterns of species richness and community composition of the SEGs in northern China.Temperature exerted a negative impact,whereas precipitation and nutrients had positive effects on species richness.Among the environmental factors used,climate was the major controller of the variations in commu-nity structure.These results provide new insights into the community composition of SEGs in China and enrich the global dataset of SEGs.展开更多
Exploration of bifunctional electrocatalysts toward effective oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is pivotal for developing high-efficiency and rechargeable metal-air batteries but remains ...Exploration of bifunctional electrocatalysts toward effective oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is pivotal for developing high-efficiency and rechargeable metal-air batteries but remains great challenging.Here we elaborately synthesize lamellar-assembled PdNi super-nanosheets(SNSs)with an optimized Pd/Ni molar ratio to serve as attractive ORR and OER bifunctional electrocatalysts for rechargeable high-powered Zn-air batteries(ZABs).The products are layer-by-layer stackings of ultrathin PdNi nanosheet motifs.On the drastically extended two-dimensional(2D)surface,the inserted Ni atoms can substantially lower down the d-band center of surface Pd toward improved ORR kinetics and concurrently create oxytropic NiOx sites to adsorb–OH groups for promoting the reverse OER electrocatalysis.Specifically,the ORR mass activity and specific activity of the primary Pd_(92)Ni_(8)SNSs attain 2.5 A·mg^(−1)and 3.15 mA·cm^(−2),which are respectively 14 and 9 times those of commercial Pt/C.Meanwhile,the OER activity and stability of Pd_(92)Ni_(8)SNSs/C distinctly outperform those of the RuO_(2)benchmark,suggesting excellent reversible oxygen electrocatalysis.The power density of the ZAB with Pd_(92)Ni_(8)SNSs/C as the air cathode is 2.7 times higher than that by Pt/C benchmark.Significantly,it can last for over 150 h without significant performance degradation during the charge–discharge cycle test.This work showcases a feasible strategy for developing self-assembled multimetallic 2D nanomaterials with excellent bifunctional catalytic performances toward energy conversion applications.展开更多
The clustering problem of big data in the era of artificial intelligence has been widely studied.Because of the huge amount of data,distributed algorithms are often used to deal with big data problems.The distributed ...The clustering problem of big data in the era of artificial intelligence has been widely studied.Because of the huge amount of data,distributed algorithms are often used to deal with big data problems.The distributed computing model has an attractive feature:it can handle massive datasets that cannot be put into the main memory.On the other hand,since many decisions are made automatically by machines in today’s society,algorithm fairness is also an important research area of machine learning.In this paper,we study two fair clustering problems:the centralized fair k-center problem with outliers and the distributed fair k-center problem with outliers.For these two problems,we have designed corresponding constant approximation ratio algorithms.The theoretical proof and analysis of the approximation ratio,and the running space of the algorithm are given.展开更多
In this paper, the superhydrophobic polyurethane sponge(SS-PU) was facilely fabricated by etching with Jones reagent to bind the nanoparticles of Ni-Co double layered oxides(LDOs) on the surface, and following modific...In this paper, the superhydrophobic polyurethane sponge(SS-PU) was facilely fabricated by etching with Jones reagent to bind the nanoparticles of Ni-Co double layered oxides(LDOs) on the surface, and following modification with n-dodecyl mercaptan(DDT). This method provides a new strategy to fabricate superhydrophobic PU sponge with a water contact angle of 157° for absorbing oil with low cost and in large scale. It exhibits the strong absorption capacity and highly selective characteristic for various kinds of oils which can be recycled by simple squeezing. Besides, the as-prepared sponge can deal with the floating and underwater oils, indicating its application value in handling oil spills and domestic oily wastewater. The good self-cleaning ability shows the potential to clear the pollutants due to the ultralow adhesion to water. Especially, the most important point is that the superhydrophobic sponge can continuously and effectively separate the oil/water mixture against the condition of turbulent disturbance by using our designed device system, which exhibit its good superhydrophobicity, strong stability.Furthermore, the SS-PU still maintained stable absorption performance after 150 cycle tests without losing capacity obviously, showing excellent durability in long-term operation and significant potential as an efficient absorbent in large-scale dispose of oily water.展开更多
Using beam propagation method （BPM）, key optical design parameters of InP/AlGaInAs multiple quantumwell （MQW） ring laser were numerically analyzed. The influences of waveguide dimensions, curvature radiusand gap s...Using beam propagation method （BPM）, key optical design parameters of InP/AlGaInAs multiple quantumwell （MQW） ring laser were numerically analyzed. The influences of waveguide dimensions, curvature radiusand gap size on the coupling efficiency were discussed. An InP/AlGaInAs MQW ring laser with radius of 350 μm wasdesigned and realized. The experimental results show that the designed device, lasing at 1 563.2 nm with side modesuppression ratio higher than 20 dB, exhibited unidirectional bistability between the clockwise and counterclockwisemodes.展开更多
Improving the slow kinetics of alkaline hydrogen electrode reactions, involving hydrogen oxidation and evolution reactions(HOR/HER) is highly desirable for accelerating the commercialization of alkaline exchange membr...Improving the slow kinetics of alkaline hydrogen electrode reactions, involving hydrogen oxidation and evolution reactions(HOR/HER) is highly desirable for accelerating the commercialization of alkaline exchange membrane-based fuel cells(AEMFCs) and water electrolyzers(AEMWEs). However, fundamental understanding of the mechanism for HOR/HER catalysis under alkaline media is still debatable. Here we develop an amorphous tungsten oxide clusters modified iridium-tungsten nanocrystallines(Ir WOx)which exhibited by far the highest exchange current density and mass activity, about three times higher than the commercial Pt/C toward alkaline HOR/HER. Density functional theory(DFT) calculations reveal the WOxclusters act as a pivotal role to boost reversible hydrogen electrode reactions in alkaline condition but via different mechanisms, which are, hydrogen binding energy(HBE) mechanism for HOR and bifunctional mechanism for HER. This work is expected to promote our fundamental understanding about the alkaline HOR/HER catalysis and provide a new avenue for rational design of highly efficient electrocatalysts toward HOR/HER under alkaline electrolytes.展开更多
Auto anti-collision technology is one of the main research subjects of automobiles’ safety technology. Aiming at the key technology of Auto anti-collision, measuring the distance from obstacles, based on the theory o...Auto anti-collision technology is one of the main research subjects of automobiles’ safety technology. Aiming at the key technology of Auto anti-collision, measuring the distance from obstacles, based on the theory of phase laser distance ranging, Laser Diode (LD) distance-measuring system for auto anti-collision has been developed to solve the problem of on-line measuring distance technology in middle to long distance utilizing the good characteristics of LD when modulating its optical intensity and adopting typical kinds of filter techniques in this paper. By theoretical analysis, adopting typical kinds of filter techniques can reduce the interference of strong light, so distance-measuring range can be 0.5–100 m in daytime or 1–200 m at night. And more, from theoretical analysis and experiment result, it can guarantee the high measuring resolution which can be less than 24.5 mm, utilizing the method of two Laser Diode optical intensity modulating wavelength and complimenting precise calibration and revision. The idea of LD distance-measuring technology is novel and feasible and this technology can be applied in Auto anti-collision. Key words laser diode - phase laser distance ranging - filter techniques - auto anti-collision CLC number TH 161 Foundation item: Supported by the National Natural Science Foundation of China (59675080, 59805006) and Wuhan Chenguang Foundation (20025001001)Biography: Zhang Xin-bao (1965-), male, Associate professor, research direction: precise mechanism and instrument.展开更多
This study investigated the heat transfer and flow characteristics of one kind of swirlgenerator in a circular heat exchanger tube through a numericalsimulation. The swirlflow induced by this type of swirlgenerator ca...This study investigated the heat transfer and flow characteristics of one kind of swirlgenerator in a circular heat exchanger tube through a numericalsimulation. The swirlflow induced by this type of swirlgenerator can obtain a high heat transfer rate with minimalpressure drop penalty. The simulations were carried out to understand the physicalbehavior of this kind of mesoscale heat enhancement component. By visualizing the heat transfer and flow characteristics, it is found that the swirlflow is induced by swirlgenerator in the circular tube couples with the impinging jet effect. After passing through the swirlgenerator, the localfriction factor of liquid can quickly return to lower levelmore quickly, while the localNusselt number maintains higher values for a distance; thus, the evaluation criterion of localperformance is improved. Single-factor optimization is used for three geometric parameters, i.e., the angle of swirlgenerator(25o, 45o, and 60o), the length of swirlgenerator(0.005, 0.01, and 0.02 m), and the center rod radius(1, 2, and 3 mm). The optimum parameters of the swirlgenerator for laminar flow of air in a circular tube are obtained, which should be 60o, 0.005 m, and 3 mm, respectively.展开更多
We couple a ladder-type three-level superconducting artificial atom to a cavity. Adjusting the artificial atom to make the cavity be resonant with the two upper levels, we then probe the lower two levels of the artifi...We couple a ladder-type three-level superconducting artificial atom to a cavity. Adjusting the artificial atom to make the cavity be resonant with the two upper levels, we then probe the lower two levels of the artificial atom. When driving the cavity to a coherent state, the probe spectrum shows energy level splitting induced by the quantized electromagnetic field in the cavity. This splitting size is related to the coupling strength between the cavity and the artificial atom and, thus, is fixed after the sample is fabricated. This is in contrast to the classical Autler-Townes splitting of a three-level system in which the splitting is proportional to the driving amplitude, which can be continuously changed. Our experiment results show the difference between the classical microwave driving field and the quantum field of the cavity.展开更多
Fluorescence microscopy has become an essential tool for biologists,to visualize the dynamics of intracellular structures with specific labeling.Quantitatively measuring the dynamics of moving objects inside the cell ...Fluorescence microscopy has become an essential tool for biologists,to visualize the dynamics of intracellular structures with specific labeling.Quantitatively measuring the dynamics of moving objects inside the cell is pivotal for understanding of the underlying regulatory mechanism.Protein-containing vesicles are involved in various biological processes such as material transportation,organelle interaction,and hormonal regulation,whose dynamic characteristics are signi¯cant to disease diagnosis and drug screening.Although some algorithms have been developed for vesicle tracking,most of them have limited performance when dealing with images with low resolution,poor signal-to-noise ratio(SNR)and complicated motion.Here,we proposed a novel deep learning-based method for intracellular vesicle tracking.We trained the U-Net for vesicle localization and motion classification,with demonstrates great performance in both simulated datasets and real biological samples.By combination with fan-shaped tracker(FsT)we have previously developed,this hybrid new algorithm significantly improved the performance of particle tracking with the function of subsequently automated vesicle motion classification.Furthermore,its performance was further demonstrated in analyzing with vesicle dynamics in different temperature,which achieved reasonable outcomes.Thus,we anticipate that this novel method would have vast applications in analyzing the vesicle dynamics in living cells.展开更多
As an intrinsic measure of smoothness, geometric continuity is an important problem in the fields of computer aided geo- metric design. It can afford more degrees of freedom for manipulating the shape of curve. Howeve...As an intrinsic measure of smoothness, geometric continuity is an important problem in the fields of computer aided geo- metric design. It can afford more degrees of freedom for manipulating the shape of curve. However, piecewise polynomial functions of geometrically continuous splines are difficult to be constructed. In this paper, the conversion matrix between geometrically con- tinuous spline basis functions and Bezier representation is analyzed. Based on this, construction of arbitrary degree geometrically continuous spline basis functions can be translated into a solution of linear system of equations. The original construction of geomet- rically continuous spline is simplified.展开更多
基金Supported by the National Key Lab Project of China(No.51435020203DZ0207)
文摘Inverse Synthetic Aperture Radar (ISAR) is an important means for target classification, recognition, identification and many other military applications. A simulation model of ISAR system is established after analyzing the principle of ISAR imaging, and then several ECM (Electronic Counter Measurement) techniques are studied. Simulation experiments are done on the basis of such research. The experimental result of the research can be used for ECM equipment.
基金supported by the Program for Chang Jiang Scholars and Innovative Research Terms in Universities(No. IRT0936)the National Basic Research Program of China (No. 2009CB219905, 2009CB219907)
文摘A wire-mesh catalyst coated by La0.8Sr0.2MnO3 was combined with a dielectric barrier discharge （DBD） reactor for toluene removal at atmospheric pressure. It was found that toluene removal efficiency and carbon dioxide selectivity were enhanced in the catalytic packed-bed reactor. In addition, ozone and nitrogen monoxide from the gas effluent byproducts decreased. This is the first time that ultrasound combined with plasma has been used for toluene removal. A synergistic effect on toluene removal was observed in the plasma-assisted ultrasound system. At the same time, the system increased toluene conversion and reduced ozone emission.
基金supported by the Natural Science Foundation of Chinathe National Key R&D Program of ChinaChinese Academy of Sciences through research projects(Grant Nos.2018YFA0305700,2021YFA1401-800,and XDB33010200)。
文摘The binary polyhydrides of heavy rare earth lutetium that shares a similar valence electron configuration to lanthanum have been experimentally discovered to be superconductive.The lutetium polyhydrides were successfully synthesized at high pressure and high temperature conditions using a diamond anvil cell in combinations with the in-situ high pressure laser heating technique.The resistance measurements as a function of temperature were performed at the same pressure of synthesis in order to study the transitions of superconductivity(SC).The superconducting transition with a maximum onset temperature(Tc)71 K was observed at pressure of 218 GPa in the experiments.The Tcdecreased to 65 K when pressure was at 181 GPa.From the evolution of SC at applied magnetic fields,the upper critical field at zero temperatureμ0Hc2(0)was obtained to be~36 T.The in-situ high pressure X-ray diffraction experiments imply that the high TcSC should arise from the Lu4H23phase with Pm3n symmetry that forms a new type of hydrogen cage framework different from those reported for previous light rare earth polyhydride superconductors.
基金supported by the National Key Technologies R&D Program of China(No.2021YFE0194000)the Fundamental Research Funds for the Central Universities of China(No.2662018PY022).
文摘Studies have shown that targeting xanthine oxidase(XO)can be a feasible treatment for fructose-induced hyperuricemia and hyperglycemia.This study aimed to evaluate the dual regulatory effects and molecular mechanisms of diacylated anthocyanins from purple sweet potato(diacylated AF-PSPs)on hyperglycemia and hyperuricemia induced by a high-fructose/high-fat diet.The body weight,organ index,serum biochemical indexes,and liver antioxidant indexes of mice were measured,and the kidneys were observed in pathological sections.The relative expression levels of messenger RNAs(mRNAs)of fructose metabolism pathway enzymes in kidney were detected by fluorescent real-time quantitative polymerase chain(qPCR)reaction technique,and the expression of renal transporter protein and inflammatory factor pathway protein was determined by immunohistochemistry(IHC)technique.Results showed that diacylated AF-PSPs alleviated hyperuricemia in mice,and that this effect might be related to the regulation of liver XO activity,lipid accumulation,and relevant renal transporters.Diacylated AF-PSPs reduced body weight and relieved lipid metabolism disorder,liver lipid accumulation,and liver oxidative stress,thereby enhancing insulin utilization and sensitivity,lowering blood sugar,and reducing hyperglycemia in mice.Also,diacylated AF-PSPs restored mRNA levels related to renal fructose metabolism,and reduced kidney injury and inflammation.This study provided experimental evidence for the mechanisms of dual regulation of blood glucose and uric acid(UA)by diacylated AF-PSPs and their utilization as functional foods in the management of metabolic syndrome.
文摘A azoreductase gene with 537 bp was obtained by PCR amplification from Rhodobacter sphaeroides AS1 1737 The enzyme, with a molecular weight of 18 7 kD, was efficiently expressed in Escherichia coli and its biodegradation characteristics for azo dyes were investigated. Furthermore, the reaction kinetics and mechanism of azo dyes catalyzed by the genetically engineered azoreductase were studied in detail. The presence of a hydrazo-intermediate was identified, which provided a convincing evidence for the assumption that azo dyes were degraded via an incomplete reduction stage.
基金supported by the National Key Research and Development Program of China(No.2022YFC2703902)the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences(Nos.2020-I2MC&T-B-003,2021-I2M-1-018)the National High Level Hospital Clinical Research Funding(No.2022-PUMCH-B-099).
文摘Background:Coronavirus disease 2019(COVID-19)has potential risks for both clinically worsening pulmonary hypertension(PH)and increasing mortality.However,the data regarding the protective role of vaccination in this population are still lacking.This study aimed to assess the safety of approved vaccination for patients with PH.Methods:In this national prospective cohort study,patients diagnosed with PH(World Health Organization[WHO]groups 1 and 4)were enrolled from October 2021 to April 2022.The primary outcome was the composite of PH-related major adverse events.We used an inverse probability weighting(IPW)approach to control for possible confounding factors in the baseline characteristics of patients.Results:In total,706 patients with PH participated in this study(mean age,40.3 years;mean duration after diagnosis of PH,8.2 years).All patients received standardized treatment for PH in accordance with guidelines for the diagnosis and treatment of PH in China.Among them,278 patients did not receive vaccination,whereas 428 patients completed the vaccination series.None of the participants were infected with COVID-19 during our study period.Overall,398 patients received inactivated severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)vaccine,whereas 30 received recombinant protein subunit vaccine.After adjusting for baseline covariates using the IPW approach,the odds of any adverse events due to PH in the vaccinated group did not statistically significantly increase(27/428[6.3%]vs.24/278[8.6%],odds ratio=0.72,P=0.302).Approximately half of the vaccinated patients reported at least one post-vaccination side effects,most of which were mild,including pain at the injection site(159/428,37.1%),fever(11/428,2.6%),and fatigue(26/428,6.1%).Conclusions:COVID-19 vaccination did not significantly augment the PH-related major adverse events for patients with WHO groups 1 and 4 PH,although there were some tolerable side effects.A large-scale randomized controlled trial is warranted to confirm this finding.The final approval
基金Th is study was supported by the National Natural Science Foundation of China(NSFC,no.40172056)the Research Fund for the Doctoral Program of Higher Education,China(RFDP,no.2000042506).
文摘With a production of 208.2 m3/d, heavy oil was produced by drill stem test (DST) from three shallow reservoirs in Sand Group Nos. Ⅰ and Ⅲ of the Neogene Guantao Formation (NgⅠ and NgⅢ) and the Eogene Dongying Formation (Ed) in an exploratory well Ban-14-1 within the Qianmiqiao region, Bohai Bay Basin, northern China. Based on the GC and GC-MS data of the NgⅠ and NgⅢ heavy oil samples, all n-alkanes and most isoprenoid hydrocarbons are lost and the GC baseline appears as an evident 'hump', implying a large quantity of unresolved complex mixture (UCM), which typically revealed a result of heavy biodegradation. However, there still is a complete series of C14-C73 n-alkanes in the high-temperature gas chromatograms (HTGC) of the heavy oil, among which, the abundance of C30- n-alkanes are drastically reduced. The C35-C55 high molecular weight (HMW) n-alkanes are at high abundance and show a normal distribution pattern with major peak at C43 and an obvious odd-carbon-number predominance with CPI37-55 and OEP45-49 values of 1.17 and 1.16-1.20, respectively. According to GC-MS analysis, the heavy oil is characterized by dual source inputs of aquatic microbes and terrestrial higher plants. Various steranes and tricyclic terpanes indicate an algal origin, and hopane-type triterpanes, C24 tetracyclic terpane and drimane series show the bacterial contribution. With the odd-carbon-number preference, HMW n-alkanes provide significant information not only on higher plant source input and immaturity, but also on the strong resistibility to biodegradation.
基金This study was funded by the National Natural Science Foundation of China(31330012,31470525,31300360,31400364)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA05050000)the China Postdoctoral Science Foundation(2013M530767,2016M591282).
文摘Aims Shrub encroachment has taken place in many of China’s northern grasslands.This study attempts to answer the following questions:which plant communities are present in these shrub-encroached grasslands(SEGs)?What are the species richness and composition of these communities?Which environmental factors determine the spatial distribution thereof?Methods We investigated the community characteristics of 255 SEG plots with a size of 20 m×20 m at 69 locations across grasslands in northern China.In each plot,paired 1-m^(2) quadrats were estab-lished within shrub patches and the neighbouring grassy matrix to record herb species composition.The quantitative character-istics(abundance,coverage and height)of herbs were meas-ured in 0.25-m2 subquadrats,and soil samples were collected in the quadrats.Two-way indicator species analysis(TWINSPAN),detrended canonical analysis(DCA)and canonical correspond-ence analysis(CCA)were used for community clustering and ordination.Important Findings The DCA and TWINSPAN results suggested that the SEGs in northern China can be divided into six community types:Potentilla fruticosa+Carex atrofusca,Spiraea hypericifolia+Festuca ovina,Caragana acanthophylla+Stipa sareptana,Caragana microphylla+Leymus chinensis,Caragana microphylla+Stipa klemenzii and Caragana tibetica+Cleistogenes songorica.At a regional scale,climate and soil nutrients controlled the spatial patterns of species richness and community composition of the SEGs in northern China.Temperature exerted a negative impact,whereas precipitation and nutrients had positive effects on species richness.Among the environmental factors used,climate was the major controller of the variations in commu-nity structure.These results provide new insights into the community composition of SEGs in China and enrich the global dataset of SEGs.
基金supported by the National Natural Science Foundation of China(No.22171093)the Natural Science Foundation of Fujian Province(Nos.2022J05058 and 2022J02008)the Scientific Research Funds of Huaqiao University(No.605-50Y21048).
文摘Exploration of bifunctional electrocatalysts toward effective oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is pivotal for developing high-efficiency and rechargeable metal-air batteries but remains great challenging.Here we elaborately synthesize lamellar-assembled PdNi super-nanosheets(SNSs)with an optimized Pd/Ni molar ratio to serve as attractive ORR and OER bifunctional electrocatalysts for rechargeable high-powered Zn-air batteries(ZABs).The products are layer-by-layer stackings of ultrathin PdNi nanosheet motifs.On the drastically extended two-dimensional(2D)surface,the inserted Ni atoms can substantially lower down the d-band center of surface Pd toward improved ORR kinetics and concurrently create oxytropic NiOx sites to adsorb–OH groups for promoting the reverse OER electrocatalysis.Specifically,the ORR mass activity and specific activity of the primary Pd_(92)Ni_(8)SNSs attain 2.5 A·mg^(−1)and 3.15 mA·cm^(−2),which are respectively 14 and 9 times those of commercial Pt/C.Meanwhile,the OER activity and stability of Pd_(92)Ni_(8)SNSs/C distinctly outperform those of the RuO_(2)benchmark,suggesting excellent reversible oxygen electrocatalysis.The power density of the ZAB with Pd_(92)Ni_(8)SNSs/C as the air cathode is 2.7 times higher than that by Pt/C benchmark.Significantly,it can last for over 150 h without significant performance degradation during the charge–discharge cycle test.This work showcases a feasible strategy for developing self-assembled multimetallic 2D nanomaterials with excellent bifunctional catalytic performances toward energy conversion applications.
基金This work was supported by the National Natural Science Foundation of China(Nos.12131003,11771386,and 11728104)the Beijing Natural Science Foundadtion Project(No.Z200002)+2 种基金the General Research Projects of Beijing Educations Committee in China(No.KM201910005013)the Natural Sciences and Engineering Research Council of Canada(NSERC)(No.06446)the General Program of Science and Technology Development Project of Beijing Municipal Education Commission(No.KM201810005005).
文摘The clustering problem of big data in the era of artificial intelligence has been widely studied.Because of the huge amount of data,distributed algorithms are often used to deal with big data problems.The distributed computing model has an attractive feature:it can handle massive datasets that cannot be put into the main memory.On the other hand,since many decisions are made automatically by machines in today’s society,algorithm fairness is also an important research area of machine learning.In this paper,we study two fair clustering problems:the centralized fair k-center problem with outliers and the distributed fair k-center problem with outliers.For these two problems,we have designed corresponding constant approximation ratio algorithms.The theoretical proof and analysis of the approximation ratio,and the running space of the algorithm are given.
基金the financial support from National Key Research & Development Program of China (2017B0602702)。
文摘In this paper, the superhydrophobic polyurethane sponge(SS-PU) was facilely fabricated by etching with Jones reagent to bind the nanoparticles of Ni-Co double layered oxides(LDOs) on the surface, and following modification with n-dodecyl mercaptan(DDT). This method provides a new strategy to fabricate superhydrophobic PU sponge with a water contact angle of 157° for absorbing oil with low cost and in large scale. It exhibits the strong absorption capacity and highly selective characteristic for various kinds of oils which can be recycled by simple squeezing. Besides, the as-prepared sponge can deal with the floating and underwater oils, indicating its application value in handling oil spills and domestic oily wastewater. The good self-cleaning ability shows the potential to clear the pollutants due to the ultralow adhesion to water. Especially, the most important point is that the superhydrophobic sponge can continuously and effectively separate the oil/water mixture against the condition of turbulent disturbance by using our designed device system, which exhibit its good superhydrophobicity, strong stability.Furthermore, the SS-PU still maintained stable absorption performance after 150 cycle tests without losing capacity obviously, showing excellent durability in long-term operation and significant potential as an efficient absorbent in large-scale dispose of oily water.
基金Supported by the National Natural Science Foundation of China(No.61106052)
文摘Using beam propagation method （BPM）, key optical design parameters of InP/AlGaInAs multiple quantumwell （MQW） ring laser were numerically analyzed. The influences of waveguide dimensions, curvature radiusand gap size on the coupling efficiency were discussed. An InP/AlGaInAs MQW ring laser with radius of 350 μm wasdesigned and realized. The experimental results show that the designed device, lasing at 1 563.2 nm with side modesuppression ratio higher than 20 dB, exhibited unidirectional bistability between the clockwise and counterclockwisemodes.
基金supported by the National Key Research and Development Program of China (2018YFB1502302)the National Natural Science Foundation of China (21972107, 21832004, and 21633008)+2 种基金the National Natural Science Foundation of Jiangsu Province (BK20191186)the Fundamental Research Funds for the Central UniversitiesLarge-scale Instrument and Equipment Sharing Foundation of Wuhan University。
文摘Improving the slow kinetics of alkaline hydrogen electrode reactions, involving hydrogen oxidation and evolution reactions(HOR/HER) is highly desirable for accelerating the commercialization of alkaline exchange membrane-based fuel cells(AEMFCs) and water electrolyzers(AEMWEs). However, fundamental understanding of the mechanism for HOR/HER catalysis under alkaline media is still debatable. Here we develop an amorphous tungsten oxide clusters modified iridium-tungsten nanocrystallines(Ir WOx)which exhibited by far the highest exchange current density and mass activity, about three times higher than the commercial Pt/C toward alkaline HOR/HER. Density functional theory(DFT) calculations reveal the WOxclusters act as a pivotal role to boost reversible hydrogen electrode reactions in alkaline condition but via different mechanisms, which are, hydrogen binding energy(HBE) mechanism for HOR and bifunctional mechanism for HER. This work is expected to promote our fundamental understanding about the alkaline HOR/HER catalysis and provide a new avenue for rational design of highly efficient electrocatalysts toward HOR/HER under alkaline electrolytes.
文摘Auto anti-collision technology is one of the main research subjects of automobiles’ safety technology. Aiming at the key technology of Auto anti-collision, measuring the distance from obstacles, based on the theory of phase laser distance ranging, Laser Diode (LD) distance-measuring system for auto anti-collision has been developed to solve the problem of on-line measuring distance technology in middle to long distance utilizing the good characteristics of LD when modulating its optical intensity and adopting typical kinds of filter techniques in this paper. By theoretical analysis, adopting typical kinds of filter techniques can reduce the interference of strong light, so distance-measuring range can be 0.5–100 m in daytime or 1–200 m at night. And more, from theoretical analysis and experiment result, it can guarantee the high measuring resolution which can be less than 24.5 mm, utilizing the method of two Laser Diode optical intensity modulating wavelength and complimenting precise calibration and revision. The idea of LD distance-measuring technology is novel and feasible and this technology can be applied in Auto anti-collision. Key words laser diode - phase laser distance ranging - filter techniques - auto anti-collision CLC number TH 161 Foundation item: Supported by the National Natural Science Foundation of China (59675080, 59805006) and Wuhan Chenguang Foundation (20025001001)Biography: Zhang Xin-bao (1965-), male, Associate professor, research direction: precise mechanism and instrument.
基金supported by the National Science and Technology Major Project of the Ministry of Science and Technology of China (No. 2016YFC0400406)
文摘This study investigated the heat transfer and flow characteristics of one kind of swirlgenerator in a circular heat exchanger tube through a numericalsimulation. The swirlflow induced by this type of swirlgenerator can obtain a high heat transfer rate with minimalpressure drop penalty. The simulations were carried out to understand the physicalbehavior of this kind of mesoscale heat enhancement component. By visualizing the heat transfer and flow characteristics, it is found that the swirlflow is induced by swirlgenerator in the circular tube couples with the impinging jet effect. After passing through the swirlgenerator, the localfriction factor of liquid can quickly return to lower levelmore quickly, while the localNusselt number maintains higher values for a distance; thus, the evaluation criterion of localperformance is improved. Single-factor optimization is used for three geometric parameters, i.e., the angle of swirlgenerator(25o, 45o, and 60o), the length of swirlgenerator(0.005, 0.01, and 0.02 m), and the center rod radius(1, 2, and 3 mm). The optimum parameters of the swirlgenerator for laminar flow of air in a circular tube are obtained, which should be 60o, 0.005 m, and 3 mm, respectively.
基金Project supported by the Science Funds from the Ministry of Science and Technology of China(Grant Nos.2014CB921401,2017YFA0304300,2014CB921202,and 2016YFA0300601)the National Natural Science Foundation of China(Grant No.11674376)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB07010300)
文摘We couple a ladder-type three-level superconducting artificial atom to a cavity. Adjusting the artificial atom to make the cavity be resonant with the two upper levels, we then probe the lower two levels of the artificial atom. When driving the cavity to a coherent state, the probe spectrum shows energy level splitting induced by the quantized electromagnetic field in the cavity. This splitting size is related to the coupling strength between the cavity and the artificial atom and, thus, is fixed after the sample is fabricated. This is in contrast to the classical Autler-Townes splitting of a three-level system in which the splitting is proportional to the driving amplitude, which can be continuously changed. Our experiment results show the difference between the classical microwave driving field and the quantum field of the cavity.
基金supported by the National Natural Science Foundation of China (No. 61474081)Guangxi Key Laboratory of Precision Navigation Technology and Application, Guilin University of Electronic Technology (No. DH201513)
基金supported by the National Key Research and Development Program of China(2021YFF0700305 and 2018YFE0119000)the National Natural Science Foundation of China(22104129 and 62105288)+1 种基金Zhejiang Province Science and Technology Research Plan(2022C03014)the Fundamental Research Funds for the Central Universities(2021XZZX022)and Alibaba Cloud.
文摘Fluorescence microscopy has become an essential tool for biologists,to visualize the dynamics of intracellular structures with specific labeling.Quantitatively measuring the dynamics of moving objects inside the cell is pivotal for understanding of the underlying regulatory mechanism.Protein-containing vesicles are involved in various biological processes such as material transportation,organelle interaction,and hormonal regulation,whose dynamic characteristics are signi¯cant to disease diagnosis and drug screening.Although some algorithms have been developed for vesicle tracking,most of them have limited performance when dealing with images with low resolution,poor signal-to-noise ratio(SNR)and complicated motion.Here,we proposed a novel deep learning-based method for intracellular vesicle tracking.We trained the U-Net for vesicle localization and motion classification,with demonstrates great performance in both simulated datasets and real biological samples.By combination with fan-shaped tracker(FsT)we have previously developed,this hybrid new algorithm significantly improved the performance of particle tracking with the function of subsequently automated vesicle motion classification.Furthermore,its performance was further demonstrated in analyzing with vesicle dynamics in different temperature,which achieved reasonable outcomes.Thus,we anticipate that this novel method would have vast applications in analyzing the vesicle dynamics in living cells.
基金Supported by NSFC (No.61100129)Long-span Building Construction Research Project (No.40006014201101)
文摘As an intrinsic measure of smoothness, geometric continuity is an important problem in the fields of computer aided geo- metric design. It can afford more degrees of freedom for manipulating the shape of curve. However, piecewise polynomial functions of geometrically continuous splines are difficult to be constructed. In this paper, the conversion matrix between geometrically con- tinuous spline basis functions and Bezier representation is analyzed. Based on this, construction of arbitrary degree geometrically continuous spline basis functions can be translated into a solution of linear system of equations. The original construction of geomet- rically continuous spline is simplified.
