Biomass,derived from plant photosynthesis that captures carbon dioxide to form carbohydrates,offers vast renewable reserves.The electrooxidation of biomass,coupled with the hydrogen evolution reaction,enables the simu...Biomass,derived from plant photosynthesis that captures carbon dioxide to form carbohydrates,offers vast renewable reserves.The electrooxidation of biomass,coupled with the hydrogen evolution reaction,enables the simultaneous production of biomass-based plastic monomers and green hydrogen,attracting significant scholarly interest.However,ambiguity remains regarding the adsorption mechanism at the catalyst surface(Langmuir-Hinshelwood or Eley-Rideal)and the adsorbed substrate groups.To address this,we prepared a Ni/Co electrode for the electrooxidation of 5-hydroxymethylfurfural(HMF)into 2,5-furandicarboxylic acid(FDCA)through a corrosion reaction and electro-reduction pathway.HMF conversion reached 100.00%,FDCA yield reached 96.82%,and Faradic efficiency(FE)reached 92.14%.Meaningfully,utilizing in-situ spectroscopy and electrochemical methods,this work provided valuable insights into active sites and catalyst surface adsorption.展开更多
Biomass conversion to value-added chemicals has received tremendous attention for solving global warming issues and fossil fuel depletion.5-Hydroxymethylfurfural(HMF)is a key bio-based platform molecule to produce man...Biomass conversion to value-added chemicals has received tremendous attention for solving global warming issues and fossil fuel depletion.5-Hydroxymethylfurfural(HMF)is a key bio-based platform molecule to produce many useful organic chemicals by oxidation,hydrogenation,polymerization,and ring-opening reactions.Among all derivatives,the oxidation product 2,5-furandicarboxylic acid(FDCA)is a promising alternative to petroleum-based terephthalic acid for the synthesis of biodegradable plastics.This review analytically discusses the recent progress in the thermocatalytic,electrocatalytic,and photocatalytic oxidation of HMF into FDCA,including catalyst screening,synthesis processes,and reaction mechanism.Rapid fundamental advances may be possible in non-precious metal and metal-free catalysts that are highly efficient under the base-free conditions,and external field-assisted processes like electrochemical or photoelectrochemical cells.展开更多
The selective oxidation of 2,5‐bis(hydroxymethyl)furan(BHMF)in this work was proven as a promising route to produce 2,5‐furandicarboxylic acid(FDCA),an emerging bio‐based building‐block with wide application.Under...The selective oxidation of 2,5‐bis(hydroxymethyl)furan(BHMF)in this work was proven as a promising route to produce 2,5‐furandicarboxylic acid(FDCA),an emerging bio‐based building‐block with wide application.Under ambient pressure,the modified carbon nanotube‐supported Pd‐based catalysts demonstrate the maximum FDCA yield of 93.0%with a full conversion of BHMF after 60 min at 60°C,much superior to that of the traditional route using 5‐hydroxymethylfurfural(HMF)as substrates(only a yield of 35.7%).The participation of PdH_(x) active species with metallic Pd can be responsible for the encouraging performance.Meanwhile,a possible reaction pathway proceeding through 2,5‐diformylfuran(DFF)and 5‐formyl‐2‐furancarboxylic acid(FFCA)as process intermediates is suggested for BHMF route.The present work may provide new opportunities to synthesize other high value‐added oxygenates by using BHMF as an alternative feedstock.展开更多
The so-called Goto's model was modified by introducing a parameter of the oxygen efficiency from industrial trials, as well as the selected and newly re-assessed thermodynamic data. The application of the model to...The so-called Goto's model was modified by introducing a parameter of the oxygen efficiency from industrial trials, as well as the selected and newly re-assessed thermodynamic data. The application of the model to copper converters in Guixi Smelter has been carried out by the combination of thermodynamic calculations with the mass and heat balance using the plant data obtained in industrial trials for many heats. For the slag-making stage, good agreements have been reached betWeen the calculated and measured temperature, blowing time as well as the contents for main elements in the matte and the slag. Relativel}'' large deviations for contents of Zn and Pb in the slag may be caused by the complex chemical composition of the real molten slag, which ma}; result in a large difference of γzn. and γPb,adopted with their real values. It is noted that the model can simulate the slag-making stage of copper converting process in industrial Pierce-Smith converters well.展开更多
Objective:Vascular endothelial growth factor(VEGF),apart from its predominant roles in angiogenesis,can enhance cancer cell proliferation,but its mechanisms remain elusive.The purpose of the present study was therefor...Objective:Vascular endothelial growth factor(VEGF),apart from its predominant roles in angiogenesis,can enhance cancer cell proliferation,but its mechanisms remain elusive.The purpose of the present study was therefore to identify how VEGF regulates cancer cell proliferation.Methods:VEGF effects on cancer cell proliferation were investigated with the VEGF receptor 2 inhibitor,Ki8751,and the breast cancer cell lines,MCF-7 and MDA-MB-231,using flow cytometry,mass spectrometry,immunoblotting,and confocal microscopy.Data were analyzed using one-way analysis of variance followed by Tukey’s multiple comparison test.Results:VEGF blockade by Ki8751 significantly reduced cancer cell proliferation,and enhanced breast cancer cell apoptosis.Mass spectrometric analyses revealed that Ki8751 treatment significantly upregulated the expression of mitochondrial proteins,suggesting the involvement of mitochondrial biogenesis.Confocal microscopy and flow cytometric analyses showed that Ki8751 treatment robustly increased the mitochondrial masses of both cancer cells,induced endomitosis,and arrested cancer cells in the high aneuploid phase.VEGFR2 knockdown by sh RNAs showed similar effects to those of Ki8751,confirming the specificity of Ki8751 treatment.Enhanced mitochondrial biogenesis increased mitochondrial oxidative phosphorylation and stimulated reactive oxygen species(ROS)production,which induced cancer cell apoptosis.Furthermore,Ki8751 treatment downregulated the phosphorylation of Akt and PGC1α,and translocated PGC1αinto the nucleus.The PGC1αalterations increased mitochondrial transcription factor A(TFAM)expression and subsequently increased mitochondrial biogenesis.Conclusions:VEGF enhances cancer cell proliferation by decreasing Akt-PGC1α-TFAM signaling-mediated mitochondrial biogenesis,ROS production,and cell apoptosis.These findings suggested the anticancer potential of Ki8751 via increased mitochondrial biogenesis and ROS production.展开更多
The National Medical Products Administration has authorized sodium oligomannate for treating mild-to-moderate Alzheimer’s disease.In this study,an LC-MS/MS method was developed and validated to quantitate sodium olig...The National Medical Products Administration has authorized sodium oligomannate for treating mild-to-moderate Alzheimer’s disease.In this study,an LC-MS/MS method was developed and validated to quantitate sodium oligomannate in different biomatrices.The plasma pharmacokinetics,tissue distribution,and excretion of sodium oligomannate in Sprague-Dawley rats and beagle dogs were systematically investigated.Despite its complicated structural composition,the absorption,distribution,metabolism,and excretion profiles of the oligosaccharides in sodium oligomannate of different sizes and terminal derivatives were indiscriminate.Sodium oligomannate mainly crossed the gastrointestinal epithelium through paracellular transport following oral administration,with very low oral bioavailability in rats(0.6%-1.6%)and dogs(4.5%-9.3%).Absorbed sodium oligomannate mainly resided in circulating body fluids in free form with minimal distribution into erythrocytes and major tissues.Sodium oligomannate could penetrate the blood-cerebrospinal fluid(CSF)barrier of rats,showing a constant area under the concentration-time curve ratio(CSF/plasma)of approximately 5%.The cumulative urinary excretion of sodium oligomannate was commensurate with its oral bioavailability,supporting that excretion was predominantly renal,whereas no obvious biliary secretion was observed following a single oral dose to bile duct-cannulated rats.Moreover,only 33.7%(male)and 26.3%(female)of the oral dose were recovered in the rat excreta within 96 h following a single oral administration,suggesting that the intestinal flora may have ingested a portion of unabsorbed sodium oligomannate as a nutrient.展开更多
Based on the dynamic shock response of the material and structure,the hypervelocity impact processes and mechanisms of long composite rods with axial density/impedance gradients penetration into fourlayer targets were...Based on the dynamic shock response of the material and structure,the hypervelocity impact processes and mechanisms of long composite rods with axial density/impedance gradients penetration into fourlayer targets were studied through experiments and numerical simulation methods.The propagation law of the shock waves,together with the structural responses of the projectiles and targets,the formation and evolution of the fragment groups formed during the processes and their distributions were described.The damage of each target plate was quantitatively analysed by comparing the results of the experiment and numerical simulation.The results showed that the axial density/impedance gradient projectiles could decrease the impact pressure to a certain extent,and the degree of damage to the target plate decreased layer by layer when the head density/impedance of the projectile was high.When the head density/impedance of the projectile was low,the degree of target damage first increased layer by layer until the projectile was completely eroded and then it decreased.The results can provide a reference for the design and application of long rods with axial composite structure for velocities ranging from 6 to 10 Ma or greater.展开更多
Goal-conditioned reinforcement learning(RL)is an interesting extension of the traditional RL framework,where the dynamic environment and reward sparsity can cause conventional learning algorithms to fail.Reward shapin...Goal-conditioned reinforcement learning(RL)is an interesting extension of the traditional RL framework,where the dynamic environment and reward sparsity can cause conventional learning algorithms to fail.Reward shaping is a practical approach to improving sample efficiency by embedding human domain knowledge into the learning process.Existing reward shaping methods for goal-conditioned RL are typically built on distance metrics with a linear and isotropic distribution,which may fail to provide sufficient information about the ever-changing environment with high complexity.This paper proposes a novel magnetic field-based reward shaping(MFRS)method for goal-conditioned RL tasks with dynamic target and obstacles.Inspired by the physical properties of magnets,we consider the target and obstacles as permanent magnets and establish the reward function according to the intensity values of the magnetic field generated by these magnets.The nonlinear and anisotropic distribution of the magnetic field intensity can provide more accessible and conducive information about the optimization landscape,thus introducing a more sophisticated magnetic reward compared to the distance-based setting.Further,we transform our magnetic reward to the form of potential-based reward shaping by learning a secondary potential function concurrently to ensure the optimal policy invariance of our method.Experiments results in both simulated and real-world robotic manipulation tasks demonstrate that MFRS outperforms relevant existing methods and effectively improves the sample efficiency of RL algorithms in goal-conditioned tasks with various dynamics of the target and obstacles.展开更多
Objective:The present study is to compare pharmacokinetics difference of carboplatin by using ultraselection uterine artery with by using peripheral vein in cervical cancer.Methods:Thirteen patients with locally advan...Objective:The present study is to compare pharmacokinetics difference of carboplatin by using ultraselection uterine artery with by using peripheral vein in cervical cancer.Methods:Thirteen patients with locally advanced cervical cancer who had been proved by pathobiology were randomly divided into two groups:the ultraselection uterine artery group(group A, n = 6) and the peripheral vein(group B, n = 7).Carboplatin was administered by infusing into artery or vein in both groups at the dosage of 300 mg/m2.Tissues from the cervical tumor were collected at different times after infusion in both groups and then analyzed.Results:The peak concentration of platinum in tumor tissue was about 2.79 times higher in group A than that of group B(P < 0.05).The platinum concentrations in tumor in group A reached its peak levels immediately after infusion.But, group B had delayed time.While, for the time point of 0 min, when the administration finished immediately, the platinum concentration in tumor was significantly higher when compared with group B(P < 0.05).The tumor tissue area under the concentration(AUC) of carboplatin was about 2 times higher in group A than that of group B(P < 0.05).Conclusion:We observed the pharmacological advantages of chemotherapy by using ultraselection uterine artery administration of chemotherapeutic agent carboplatin in tumor tissue which provided theoretical basis and laboratory parameters of the intra-arterial chemotherapy for gynecologic malignancy.展开更多
In this paper, a probabilistic fuzzy approach is proposed for mobile-robot reactive navigation using range sensors. The primary motivation is an integrated reactive navigation control system with good real-time perfor...In this paper, a probabilistic fuzzy approach is proposed for mobile-robot reactive navigation using range sensors. The primary motivation is an integrated reactive navigation control system with good real-time performance under uncertainty. To accomplish this aim, a probabilistic fuzzy logic system (PFLS) is introduced to range measurement and reactive navigation in local environments. PFLS is first adopted to handle the fuzzy and stochastic uncertainties in range sensors and to provide more precise distance information in unknown environments. Consequently these sensor data are sent to a probabilistic fuzzy rule-based inference system with reactive behaviors for local navigation. The feasibility and effectiveness of the proposed approach are verified by simulation and the experiments on a real mobile robot.展开更多
The purpose of this study is to investigate the expression of major potassium channel subtypes in the brain of chronical mild stress (CMS) rats and reveal the effects of fluoxetine on the expression of these channels....The purpose of this study is to investigate the expression of major potassium channel subtypes in the brain of chronical mild stress (CMS) rats and reveal the effects of fluoxetine on the expression of these channels. Rats were exposed to a variety of unpredictable stress for three weeks and induced anhedonia, lower sucrose preference, locomotor activity and lower body weight The protein expressions were determined by Western blot. CMS significantly increased the expression of Kv2.1 channel in frontal cortex but not in hippocampus, and the expression level was normalized after fluoxetine treatment. the expression of TREK-1 channel was also obviously increased in frontal cortex in CMS rats. Fluoxetine treatment might prevent this increase. However, the expression of Kv3.1 and Kv4.2 channels was considerably decreased in hippocampus after CMS, and was not affected by fluoxetine. These results suggest that different subtypes of potassium channels are associated with the pathophy-siology of depression and that the therapeutical effects of fluoxetine may relate to Kv2.1 and TREK-1 potassium channels. (C) 2015 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V. All rights reserved.展开更多
Establishing how lineages with similar traits are phylogenetically related remains critical for understanding the origin of biodiversity on Earth.Floral traits in plants are widely used to explore phylogenetic relatio...Establishing how lineages with similar traits are phylogenetically related remains critical for understanding the origin of biodiversity on Earth.Floral traits in plants are widely used to explore phylogenetic relationships and to delineate taxonomic groups.The subtribe Swertiinae(Gentianaceae)comprises more than 350 species with high floral diversity ranging from rotate to tubular corollas and possessing diverse nectaries.Here we performed phylogenetic analysis of 60 species from all 15 genera of the subtribe Swertiinae sensu Ho and Liu,representing the range of floral diversity,using data from the nuclear and plastid genomes.Extensive topological conflicts were present between the nuclear and plastome trees.Three of the 15 genera represented by multiple species are polyphyletic in both trees.Key floral traits including corolla type,absence or presence of lobe scales,nectary type,nectary position,and stigma type are randomly distributed in the nuclear and plastome trees without phylogenetic correlation.We also revealed the likely ancient hybrid origin of one large clade comprising 10 genera with diverse floral traits.These results highlight the complex evolutionary history of this subtribe.The phylogenies constructed here provide a basic framework for further exploring the ecological and genetic mechanisms underlying both species diversification and floral diversity.展开更多
Ferric-chelate reductase which functions in the reduction of ferric to ferrous iron on root surface is a critical protein for iron ho- meostasis in strategy I plants. LeFROI is a major ferric-chelate reductase involve...Ferric-chelate reductase which functions in the reduction of ferric to ferrous iron on root surface is a critical protein for iron ho- meostasis in strategy I plants. LeFROI is a major ferric-chelate reductase involved in iron uptake in tomato. To identify the natural variations of LeFRO1 and to assess their effect on the ferric-chelate reductase activity, we cloned the coding sequences of LeFRO1 from 16 tomato varieties collected from different regions, and detected three types of LeFRO1 （LeFRO1MM, LeFRO1Ailsa and LeFRO1Monita） with five amino acid variations at the positions 21, 24, 112, 195 and 582. Enzyme activity assay revealed that the three types of LeFRO1 possessed different ferric-chelate reductase activity （LeFRO1AiISa 〉 LeFRO1MM 〉 LeFRO1M^nita）. The 112th amino acid residue Ala of LeFRO1 is critical for maintaining the high activity of ferric-chelate reductase, because modification of this amino acid resulted in a significant reduction of enzyme activity. Further, we showed that the combination of the amino acid residue lie at the site 24 with Lys at the site 582 played a positive role in the enzyme activity of LeFRO1. In conclusion, the findings are helpful to understand the natural adaptation mechanisms of plants to iron-limiting stress, and may provide new knowledge to select and manipulate LeFRO1 for improving the iron deficiency tolerance in tomato.展开更多
Ozone treatment is a common way to functionalize commercial multi-walled carbon nanotubes （CNTs） with various oxygen functionalities like carboxyl, phenol and lactone groups, in order to enhance their textural prope...Ozone treatment is a common way to functionalize commercial multi-walled carbon nanotubes （CNTs） with various oxygen functionalities like carboxyl, phenol and lactone groups, in order to enhance their textural properties and chemical activity. In order to detail the effect of each functional group, we correlated the activity with the surface density of each group, and found that the carboxyl groups play a pivotal role in two important catalytic reactions, namely the electrochemical oxygen reduction reaction （ORR） and agar conversion to 5-hydroxymethylfurfural （HMF）. During the processes, the hydrophilic surface provides a strong affinity for reaction substrates while the improved porosity allows the efficient diffusion of reactants and products. Furthermore, the activity of functionalized CNTs for agar conversion remained almost unchanged during nine cycles of reaction. This work highlights a strategy for improving the activity of CNTs for electrochemical ORR and agar conversion reactions, as well a promising application of carboxyl-rich CNTs as a solid acid catalyst to produce high-purity HMF--an important chemical intermediate.展开更多
基金the financial support from the National Natural Science Foundation of China(22072170)the Zhejiang Provincial Key Research and Development Program(2021C03170)the Ningbo Science and Technology Bureau(2019B10096)。
文摘Biomass,derived from plant photosynthesis that captures carbon dioxide to form carbohydrates,offers vast renewable reserves.The electrooxidation of biomass,coupled with the hydrogen evolution reaction,enables the simultaneous production of biomass-based plastic monomers and green hydrogen,attracting significant scholarly interest.However,ambiguity remains regarding the adsorption mechanism at the catalyst surface(Langmuir-Hinshelwood or Eley-Rideal)and the adsorbed substrate groups.To address this,we prepared a Ni/Co electrode for the electrooxidation of 5-hydroxymethylfurfural(HMF)into 2,5-furandicarboxylic acid(FDCA)through a corrosion reaction and electro-reduction pathway.HMF conversion reached 100.00%,FDCA yield reached 96.82%,and Faradic efficiency(FE)reached 92.14%.Meaningfully,utilizing in-situ spectroscopy and electrochemical methods,this work provided valuable insights into active sites and catalyst surface adsorption.
基金supported by Chinese Academy of Sciences(QYZDB-SSW-JSC037)Natural Science Foundation of Zhejiang Province(LY19B030003,LQ19B060002)+1 种基金Ningbo Science and Technology Bureau(2018B10056,2019B10096)Fujian Institute of Innovation(FJCXY18020202)。
文摘Biomass conversion to value-added chemicals has received tremendous attention for solving global warming issues and fossil fuel depletion.5-Hydroxymethylfurfural(HMF)is a key bio-based platform molecule to produce many useful organic chemicals by oxidation,hydrogenation,polymerization,and ring-opening reactions.Among all derivatives,the oxidation product 2,5-furandicarboxylic acid(FDCA)is a promising alternative to petroleum-based terephthalic acid for the synthesis of biodegradable plastics.This review analytically discusses the recent progress in the thermocatalytic,electrocatalytic,and photocatalytic oxidation of HMF into FDCA,including catalyst screening,synthesis processes,and reaction mechanism.Rapid fundamental advances may be possible in non-precious metal and metal-free catalysts that are highly efficient under the base-free conditions,and external field-assisted processes like electrochemical or photoelectrochemical cells.
文摘The selective oxidation of 2,5‐bis(hydroxymethyl)furan(BHMF)in this work was proven as a promising route to produce 2,5‐furandicarboxylic acid(FDCA),an emerging bio‐based building‐block with wide application.Under ambient pressure,the modified carbon nanotube‐supported Pd‐based catalysts demonstrate the maximum FDCA yield of 93.0%with a full conversion of BHMF after 60 min at 60°C,much superior to that of the traditional route using 5‐hydroxymethylfurfural(HMF)as substrates(only a yield of 35.7%).The participation of PdH_(x) active species with metallic Pd can be responsible for the encouraging performance.Meanwhile,a possible reaction pathway proceeding through 2,5‐diformylfuran(DFF)and 5‐formyl‐2‐furancarboxylic acid(FFCA)as process intermediates is suggested for BHMF route.The present work may provide new opportunities to synthesize other high value‐added oxygenates by using BHMF as an alternative feedstock.
文摘The so-called Goto's model was modified by introducing a parameter of the oxygen efficiency from industrial trials, as well as the selected and newly re-assessed thermodynamic data. The application of the model to copper converters in Guixi Smelter has been carried out by the combination of thermodynamic calculations with the mass and heat balance using the plant data obtained in industrial trials for many heats. For the slag-making stage, good agreements have been reached betWeen the calculated and measured temperature, blowing time as well as the contents for main elements in the matte and the slag. Relativel}'' large deviations for contents of Zn and Pb in the slag may be caused by the complex chemical composition of the real molten slag, which ma}; result in a large difference of γzn. and γPb,adopted with their real values. It is noted that the model can simulate the slag-making stage of copper converting process in industrial Pierce-Smith converters well.
基金supported by grants from the Swedish HeartLung Foundation(Grant No.20160419)the Swedish Research Council+5 种基金the Swedish Foundation for International Cooperation in Research and Higher Educationthe National Natural Science Foundation of China(Grant Nos.81700110 and 8171101454)the China Scholarship CouncilKarolinska InstitutetShandong University-Karolinska Institutet Cooperative Research Fundthe Stockholm County Council。
文摘Objective:Vascular endothelial growth factor(VEGF),apart from its predominant roles in angiogenesis,can enhance cancer cell proliferation,but its mechanisms remain elusive.The purpose of the present study was therefore to identify how VEGF regulates cancer cell proliferation.Methods:VEGF effects on cancer cell proliferation were investigated with the VEGF receptor 2 inhibitor,Ki8751,and the breast cancer cell lines,MCF-7 and MDA-MB-231,using flow cytometry,mass spectrometry,immunoblotting,and confocal microscopy.Data were analyzed using one-way analysis of variance followed by Tukey’s multiple comparison test.Results:VEGF blockade by Ki8751 significantly reduced cancer cell proliferation,and enhanced breast cancer cell apoptosis.Mass spectrometric analyses revealed that Ki8751 treatment significantly upregulated the expression of mitochondrial proteins,suggesting the involvement of mitochondrial biogenesis.Confocal microscopy and flow cytometric analyses showed that Ki8751 treatment robustly increased the mitochondrial masses of both cancer cells,induced endomitosis,and arrested cancer cells in the high aneuploid phase.VEGFR2 knockdown by sh RNAs showed similar effects to those of Ki8751,confirming the specificity of Ki8751 treatment.Enhanced mitochondrial biogenesis increased mitochondrial oxidative phosphorylation and stimulated reactive oxygen species(ROS)production,which induced cancer cell apoptosis.Furthermore,Ki8751 treatment downregulated the phosphorylation of Akt and PGC1α,and translocated PGC1αinto the nucleus.The PGC1αalterations increased mitochondrial transcription factor A(TFAM)expression and subsequently increased mitochondrial biogenesis.Conclusions:VEGF enhances cancer cell proliferation by decreasing Akt-PGC1α-TFAM signaling-mediated mitochondrial biogenesis,ROS production,and cell apoptosis.These findings suggested the anticancer potential of Ki8751 via increased mitochondrial biogenesis and ROS production.
基金supported by the National Natural Science Foundation of China(Grant No.:81673388)the Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases(Grant No.:BM2013003)the Priority Academic Program Development of Jiangsu Higher Education Institutes(PAPD)
文摘The National Medical Products Administration has authorized sodium oligomannate for treating mild-to-moderate Alzheimer’s disease.In this study,an LC-MS/MS method was developed and validated to quantitate sodium oligomannate in different biomatrices.The plasma pharmacokinetics,tissue distribution,and excretion of sodium oligomannate in Sprague-Dawley rats and beagle dogs were systematically investigated.Despite its complicated structural composition,the absorption,distribution,metabolism,and excretion profiles of the oligosaccharides in sodium oligomannate of different sizes and terminal derivatives were indiscriminate.Sodium oligomannate mainly crossed the gastrointestinal epithelium through paracellular transport following oral administration,with very low oral bioavailability in rats(0.6%-1.6%)and dogs(4.5%-9.3%).Absorbed sodium oligomannate mainly resided in circulating body fluids in free form with minimal distribution into erythrocytes and major tissues.Sodium oligomannate could penetrate the blood-cerebrospinal fluid(CSF)barrier of rats,showing a constant area under the concentration-time curve ratio(CSF/plasma)of approximately 5%.The cumulative urinary excretion of sodium oligomannate was commensurate with its oral bioavailability,supporting that excretion was predominantly renal,whereas no obvious biliary secretion was observed following a single oral dose to bile duct-cannulated rats.Moreover,only 33.7%(male)and 26.3%(female)of the oral dose were recovered in the rat excreta within 96 h following a single oral administration,suggesting that the intestinal flora may have ingested a portion of unabsorbed sodium oligomannate as a nutrient.
基金supported by the National Natural Science Foundation of China(Grant No.11772269)。
文摘Based on the dynamic shock response of the material and structure,the hypervelocity impact processes and mechanisms of long composite rods with axial density/impedance gradients penetration into fourlayer targets were studied through experiments and numerical simulation methods.The propagation law of the shock waves,together with the structural responses of the projectiles and targets,the formation and evolution of the fragment groups formed during the processes and their distributions were described.The damage of each target plate was quantitatively analysed by comparing the results of the experiment and numerical simulation.The results showed that the axial density/impedance gradient projectiles could decrease the impact pressure to a certain extent,and the degree of damage to the target plate decreased layer by layer when the head density/impedance of the projectile was high.When the head density/impedance of the projectile was low,the degree of target damage first increased layer by layer until the projectile was completely eroded and then it decreased.The results can provide a reference for the design and application of long rods with axial composite structure for velocities ranging from 6 to 10 Ma or greater.
基金supported in part by the National Natural Science Foundation of China(62006111,62073160)the Natural Science Foundation of Jiangsu Province of China(BK20200330)。
文摘Goal-conditioned reinforcement learning(RL)is an interesting extension of the traditional RL framework,where the dynamic environment and reward sparsity can cause conventional learning algorithms to fail.Reward shaping is a practical approach to improving sample efficiency by embedding human domain knowledge into the learning process.Existing reward shaping methods for goal-conditioned RL are typically built on distance metrics with a linear and isotropic distribution,which may fail to provide sufficient information about the ever-changing environment with high complexity.This paper proposes a novel magnetic field-based reward shaping(MFRS)method for goal-conditioned RL tasks with dynamic target and obstacles.Inspired by the physical properties of magnets,we consider the target and obstacles as permanent magnets and establish the reward function according to the intensity values of the magnetic field generated by these magnets.The nonlinear and anisotropic distribution of the magnetic field intensity can provide more accessible and conducive information about the optimization landscape,thus introducing a more sophisticated magnetic reward compared to the distance-based setting.Further,we transform our magnetic reward to the form of potential-based reward shaping by learning a secondary potential function concurrently to ensure the optimal policy invariance of our method.Experiments results in both simulated and real-world robotic manipulation tasks demonstrate that MFRS outperforms relevant existing methods and effectively improves the sample efficiency of RL algorithms in goal-conditioned tasks with various dynamics of the target and obstacles.
基金Supported by a grant from the Nature Sciences of Guangdong Province(No. 06024389).
文摘Objective:The present study is to compare pharmacokinetics difference of carboplatin by using ultraselection uterine artery with by using peripheral vein in cervical cancer.Methods:Thirteen patients with locally advanced cervical cancer who had been proved by pathobiology were randomly divided into two groups:the ultraselection uterine artery group(group A, n = 6) and the peripheral vein(group B, n = 7).Carboplatin was administered by infusing into artery or vein in both groups at the dosage of 300 mg/m2.Tissues from the cervical tumor were collected at different times after infusion in both groups and then analyzed.Results:The peak concentration of platinum in tumor tissue was about 2.79 times higher in group A than that of group B(P < 0.05).The platinum concentrations in tumor in group A reached its peak levels immediately after infusion.But, group B had delayed time.While, for the time point of 0 min, when the administration finished immediately, the platinum concentration in tumor was significantly higher when compared with group B(P < 0.05).The tumor tissue area under the concentration(AUC) of carboplatin was about 2 times higher in group A than that of group B(P < 0.05).Conclusion:We observed the pharmacological advantages of chemotherapy by using ultraselection uterine artery administration of chemotherapeutic agent carboplatin in tumor tissue which provided theoretical basis and laboratory parameters of the intra-arterial chemotherapy for gynecologic malignancy.
文摘In this paper, a probabilistic fuzzy approach is proposed for mobile-robot reactive navigation using range sensors. The primary motivation is an integrated reactive navigation control system with good real-time performance under uncertainty. To accomplish this aim, a probabilistic fuzzy logic system (PFLS) is introduced to range measurement and reactive navigation in local environments. PFLS is first adopted to handle the fuzzy and stochastic uncertainties in range sensors and to provide more precise distance information in unknown environments. Consequently these sensor data are sent to a probabilistic fuzzy rule-based inference system with reactive behaviors for local navigation. The feasibility and effectiveness of the proposed approach are verified by simulation and the experiments on a real mobile robot.
基金supported by a grant from the National Science and Technology Major Special Project on Major New Drug Innovation of China (Nos. 2012ZX09301002-004 and 2014ZX09507003006-003)
文摘The purpose of this study is to investigate the expression of major potassium channel subtypes in the brain of chronical mild stress (CMS) rats and reveal the effects of fluoxetine on the expression of these channels. Rats were exposed to a variety of unpredictable stress for three weeks and induced anhedonia, lower sucrose preference, locomotor activity and lower body weight The protein expressions were determined by Western blot. CMS significantly increased the expression of Kv2.1 channel in frontal cortex but not in hippocampus, and the expression level was normalized after fluoxetine treatment. the expression of TREK-1 channel was also obviously increased in frontal cortex in CMS rats. Fluoxetine treatment might prevent this increase. However, the expression of Kv3.1 and Kv4.2 channels was considerably decreased in hippocampus after CMS, and was not affected by fluoxetine. These results suggest that different subtypes of potassium channels are associated with the pathophy-siology of depression and that the therapeutical effects of fluoxetine may relate to Kv2.1 and TREK-1 potassium channels. (C) 2015 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V. All rights reserved.
基金supported by the Natural Science Foundation of China(32170221)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB31000000)Fundamental Research Funds for the Central Universities(YJ201936,SCU2019D013 and 2020SCUNL20)。
文摘Establishing how lineages with similar traits are phylogenetically related remains critical for understanding the origin of biodiversity on Earth.Floral traits in plants are widely used to explore phylogenetic relationships and to delineate taxonomic groups.The subtribe Swertiinae(Gentianaceae)comprises more than 350 species with high floral diversity ranging from rotate to tubular corollas and possessing diverse nectaries.Here we performed phylogenetic analysis of 60 species from all 15 genera of the subtribe Swertiinae sensu Ho and Liu,representing the range of floral diversity,using data from the nuclear and plastid genomes.Extensive topological conflicts were present between the nuclear and plastome trees.Three of the 15 genera represented by multiple species are polyphyletic in both trees.Key floral traits including corolla type,absence or presence of lobe scales,nectary type,nectary position,and stigma type are randomly distributed in the nuclear and plastome trees without phylogenetic correlation.We also revealed the likely ancient hybrid origin of one large clade comprising 10 genera with diverse floral traits.These results highlight the complex evolutionary history of this subtribe.The phylogenies constructed here provide a basic framework for further exploring the ecological and genetic mechanisms underlying both species diversification and floral diversity.
基金supported by the grants from the Ministry of Science and Technology of China(No.2011CB 100304)the Ministry of Agriculture of China(No.2011ZX08009-003005)the HarvestPlus Challenge Program(Agreement#8274)
文摘Ferric-chelate reductase which functions in the reduction of ferric to ferrous iron on root surface is a critical protein for iron ho- meostasis in strategy I plants. LeFROI is a major ferric-chelate reductase involved in iron uptake in tomato. To identify the natural variations of LeFRO1 and to assess their effect on the ferric-chelate reductase activity, we cloned the coding sequences of LeFRO1 from 16 tomato varieties collected from different regions, and detected three types of LeFRO1 （LeFRO1MM, LeFRO1Ailsa and LeFRO1Monita） with five amino acid variations at the positions 21, 24, 112, 195 and 582. Enzyme activity assay revealed that the three types of LeFRO1 possessed different ferric-chelate reductase activity （LeFRO1AiISa 〉 LeFRO1MM 〉 LeFRO1M^nita）. The 112th amino acid residue Ala of LeFRO1 is critical for maintaining the high activity of ferric-chelate reductase, because modification of this amino acid resulted in a significant reduction of enzyme activity. Further, we showed that the combination of the amino acid residue lie at the site 24 with Lys at the site 582 played a positive role in the enzyme activity of LeFRO1. In conclusion, the findings are helpful to understand the natural adaptation mechanisms of plants to iron-limiting stress, and may provide new knowledge to select and manipulate LeFRO1 for improving the iron deficiency tolerance in tomato.
文摘Ozone treatment is a common way to functionalize commercial multi-walled carbon nanotubes （CNTs） with various oxygen functionalities like carboxyl, phenol and lactone groups, in order to enhance their textural properties and chemical activity. In order to detail the effect of each functional group, we correlated the activity with the surface density of each group, and found that the carboxyl groups play a pivotal role in two important catalytic reactions, namely the electrochemical oxygen reduction reaction （ORR） and agar conversion to 5-hydroxymethylfurfural （HMF）. During the processes, the hydrophilic surface provides a strong affinity for reaction substrates while the improved porosity allows the efficient diffusion of reactants and products. Furthermore, the activity of functionalized CNTs for agar conversion remained almost unchanged during nine cycles of reaction. This work highlights a strategy for improving the activity of CNTs for electrochemical ORR and agar conversion reactions, as well a promising application of carboxyl-rich CNTs as a solid acid catalyst to produce high-purity HMF--an important chemical intermediate.
