BACKGROUND The magnetic compression technique has been used to establish an animal model of tracheoesophageal fistula(TEF),but the commonly shaped magnets present limitations of poor homogeneity of TEF and poor model ...BACKGROUND The magnetic compression technique has been used to establish an animal model of tracheoesophageal fistula(TEF),but the commonly shaped magnets present limitations of poor homogeneity of TEF and poor model control.We designed a Tshaped magnet system to overcome these problems and verified its effectiveness via animal experiments.AIM To investigate the effectiveness of a T-shaped magnet system for establishing a TEF model in beagle dogs.METHODS Twelve beagles were randomly assigned to groups in which magnets of the Tshaped scheme(study group,n=6)or normal magnets(control group,n=6)were implanted into the trachea and esophagus separately under gastroscopy.Operation time,operation success rate,and accidental injury were recorded.After operation,the presence and timing of cough and the time of magnet shedding were observed.Dogs in the control group were euthanized after X-ray and gastroscopy to confirm establishment of TEFs after coughing,and gross specimens of TEFs were obtained.Dogs in the study group were euthanized after X-ray and gastroscopy 2 wk after surgery,and gross specimens were obtained.Fistula size was measured in all animals,and then harvested fistula specimens were examined by hematoxylin and eosin(HE)and Masson trichrome staining.RESULTS The operation success rate was 100%for both groups.Operation time did not differ between the study group(5.25 min±1.29 min)and the control group(4.75 min±1.70 min;P=0.331).No bleeding,perforation,or unplanned magnet attraction occurred in any animal during the operation.In the early postoperative period,all dogs ate freely and were generally in good condition.Dogs in the control group had severe cough after drinking water at 6-9 d after surgery.X-ray indicated that the magnets had entered the stomach,and gastroscopy showed TEF formation.Gross specimens of TEFs from the control group showed the formation of fistulas with a diameter of 4.94 mm±1.29 mm(range,3.52-6.56 mm).HE and Masson trichrome staining showed scar tissue formation and hierarchical structural disorder at the fistulas.Dogs in the study group did not exhibit obvious coughing after surgery.X-ray examination 2 wk after surgery indicated fixed magnet positioning,and gastroscopy showed no change in magnet positioning.The magnets were removed using a snare under endoscopy,and TEF was observed.Gross specimens showed well-formed fistulas with a diameter of 6.11 mm±0.16 mm(range,5.92-6.36 mm),which exceeded that in the control group(P<0.001).Scar formation was observed on the internal surface of fistulas by HE and Masson trichrome staining,and the structure was more regular than that in the control group.CONCLUSION Use of the modified T-shaped magnet scheme is safe and feasible for establishing TEF and can achieve a more stable and uniform fistula size compared with ordinary magnets.Most importantly,this model offers better controllability,which improves the flexibility of follow-up studies.展开更多
Under the carbon neutrality goal,coal enterprises must seek breakthroughs from abandoned mines,develop new resources in the new era,turn problems into countermeasures,and participate in the carbon emissions market,for...Under the carbon neutrality goal,coal enterprises must seek breakthroughs from abandoned mines,develop new resources in the new era,turn problems into countermeasures,and participate in the carbon emissions market,for contributing to the accomplishment of the national strategic goal of carbon neutrality.To this end,we investigated the relevant national policies and regulations to clarify the boundaries disclosed by the carbon information of enterprises,understood the development direction of carbon storage in abandoned mines,and clarified the transformation and development of carbon storage in aban-doned mines.We made a few suggestions:(1)China should learn from its past experience and other countries to develop the energy industry with Chinese characteristics and reform the economic system.(2)Coal enterprises must actively respond to the national carbon information disclosure policy,clarify their own responsibilities and carbon emission boundaries.(3)It is necessary to proactively obtain advanced knowledge and plan carbon storage pathways for abandoned mines.(4)Devel-opment problems of coal enterprises should be deduced using cases.The'dual carbon'goals should be achieved steadily step-by-step.(5)Three measures,i.e.improving the existing resource structure,coordinating the information of abandoned mines,and promoting the cultivation of scientific and technological talents.展开更多
Food provides abundant nutrients for human beings, but also has sensory functions and physiological regulation.Lipids are the main components of food as well as the important structural and functional components of ce...Food provides abundant nutrients for human beings, but also has sensory functions and physiological regulation.Lipids are the main components of food as well as the important structural and functional components of cells.Nevertheless, lipids are easily oxidized by different ways, such as thermal oxidation and air oxidation. Lipidoxidation has adverse effects on food quality and human health. Therefore, efforts should be made to reduce lipidoxidation and improve its stability. This review focuses on important knowledge about lipid oxidation, includingthe concept of lipids and lipid oxidation, the main pathways and mechanisms of lipid oxidation, factors affectinglipid oxidation, strategies to improve the stability of lipid oxidation, and the recent research progress of lipidoxidation in food science and nutritional health.展开更多
Verticillium wilt(VW)is a common soilborne disease of cotton.It occurs mainly in the seedling and bollopening stages and severely impairs the yield and quality of the fiber.Rapid and accurate identification and evalua...Verticillium wilt(VW)is a common soilborne disease of cotton.It occurs mainly in the seedling and bollopening stages and severely impairs the yield and quality of the fiber.Rapid and accurate identification and evaluation of VW severity(VWS)forms the basis of field cotton VW control,which has great significance to cotton production.Cotton VWS values are conventionally measured using in-field observations and laboratory test diagnoses,which require abundant time and professional expertise.Remote and proximal sensing using imagery and spectrometry have great potential for this purpose.In this study,we performed in situ investigations at three experimental sites in 2019 and 2021 and collected VWS values,in situ images,and spectra of 361 cotton canopies.To estimate cotton VWS values at the canopy scale,we developed two deep learning approaches that use in situ images and spectra,respectively.For the imagery-based method,given the high complexity of the in situ environment,we first transformed the task of healthy and diseased leaf recognition to the task of cotton field scene classification and then built a cotton field scenes(CFS)dataset with over 1000 images for each scene-unit type.We performed pretrained convolutional neural networks(CNNs)training and validation using the CFS dataset and then used the networks after training to classify scene units for each canopy.The results showed that the Dark Net-19 model achieved satisfactory performance in CFS classification and VWS values estimation(R^(2)=0.91,root-mean-square error(RMSE)=6.35%).For the spectroscopy-based method,we first designed a one-dimensional regression network(1D CNN)with four convolutional layers.After dimensionality reduction by sensitive-band selection and principal component analysis,we fitted the 1D CNN with varying numbers of principal components(PCs).The 1D CNN model with the top 20 PCs performed best(R^(2)=0.93,RMSE=5.77%).These deep learning-driven approaches offer the potential of assessing crop disease severity from spatial and spectral perspectives.展开更多
DHA-enriched eggs have gained popularity due to their unique nutritional value,but their flavor can be challenging for some consumers to accept.The study analyzed the correlation of lipids and flavors in DHA-enriched ...DHA-enriched eggs have gained popularity due to their unique nutritional value,but their flavor can be challenging for some consumers to accept.The study analyzed the correlation of lipids and flavors in DHA-enriched egg yolks using comprehensive lipidomics and volatile compound analysis.The results showed that 411 lipids were detected in two egg yolk samples.Among them,148 lipid species,including 48 DHA-containing lipids,were significantly higher in DHA-enriched egg yolks than in Common ones(P<0.05).Furthermore,of the 24 volatile compounds detected,the contents of benzaldehyde,heptanal,hexanal,decanal and 2-nonanone in DHA-enriched egg yolks were significantly higher than in Common egg yolks(P<0.05).The“fishy”smell characteristic of DHAenriched egg yolks was mainly caused by volatile aldehydes,which may be produced through the hydrolysis of lipids in the egg yolk to free fatty acids and further oxidation.Analysis of the correlation network diagram revealed that phospholipids containing docosahexaenoic acid(DHA),linoleic acid,or oleic acid chains were the main contributors to the characteristic flavor of DHA-enriched egg yolks.Overall,this study explored the effect of different lipids on the flavor of DHA-enriched egg yolks and provided a theoretical basis for the production and improvement of DHA-enriched eggs.展开更多
To investigate the impact of dietary supplementation of different omega-3 polyunsaturated fatty acids (n-3 PUFAs) resources on PUFAs enrichment in hen eggs, two supplemental materials, flaxseed and oil-extracted micro...To investigate the impact of dietary supplementation of different omega-3 polyunsaturated fatty acids (n-3 PUFAs) resources on PUFAs enrichment in hen eggs, two supplemental materials, flaxseed and oil-extracted microalgal residue of heterotrophic Schizochytrium, were added to the diet of laying hens in 3 groups. Results showed that supplementation with flaxseed and Schizochytrium residue gave rise to the increased, but different n-3 PUFAs levels in egg yolk, mainly α-linolenic acid (ALA) and docosahexaenoic acid (DHA). The ratio of n-6/n-3 PUFAs was reduced in all groups. After 14 days feeding of supplied PUFAs resources, n-3 PUFAs contents reached a plateau, and then remained constant during further supplementation in 3 experimental groups. Both the highest ALA level and DHA level were achieved in flaxseed group and microalgae group, reaching up to 353.69 (±68.15) mg/egg and 301.41 (± 26.76) mg/egg respectively. Moreover, the n-3 PUFAs enrichment efficiency was relatively low in flaxseed group when compared to other 2 groups. Laying rates of hens before entering peak production period could be improved by adding flaxseed but was not obviously affected by Schizochytrium residue. The egg weight, on the other hand, had no relationship with dietary supplementation. Thus, supplementation of flaxseed or Schizochytrium residue into standard feed offers an alternative choice for the production of n-3 PUFAs enriched eggs.展开更多
This paper studies the contact vibration problem of an elastic half-space coated with functionally graded materials(FGMs)subject to a rigid spherical punch.A static force superimposing a dynamic time-harmonic force ac...This paper studies the contact vibration problem of an elastic half-space coated with functionally graded materials(FGMs)subject to a rigid spherical punch.A static force superimposing a dynamic time-harmonic force acts on the rigid spherical punch.Firstly,we give the static contact problem of FGMs by a least-square fitting approach.Next,the dynamic contact pressure is solved by employing the perturbation method.Lastly,the dynamic contact stiffness with different dynamic contact displacement conditions is derived for the FGM coated half-space.The effects of the gradient index,coating thickness,internal friction,and punch radius on the dynamic contact stiffness factor are discussed in detail.展开更多
A polysilicon separated CMOS Schottky barrier diode is designed and tested in this study.By replacing the shallow trench isolation(STI)of a ploy ring,the series resistances of Schottky diodes are reduced,leading to ...A polysilicon separated CMOS Schottky barrier diode is designed and tested in this study.By replacing the shallow trench isolation(STI)of a ploy ring,the series resistances of Schottky diodes are reduced,leading to an improvement in cut-off frequencies.The device structure is detailed and a device model is developed.Our analysis on the device shows that the cut-off frequency increases with the decreasing of the Schottky contact area.Based on this observation,the Schottky contact area is set to0.38×0.38μm^2,which is the minimum contact diffusion area allowed by the process flow.The distance between the anode and the cathode is also discussed.Diodes with different dimensions are fabricated and measured.Through extensive measurements,the optimum dimensions are obtained.Bondpads with a reduced area are used to improve the measurement accuracy.The measurement results show that these diodes can achieve a cut-off frequency of 1.5 THz.Thus,it is possible to use these diodes in THz detection.展开更多
A wideband polarization reconfigurable dielectric resonator antenna excited by quasilumped quadrature coupler( QLQC) is proposed. By adjusting the value of varactor diode on the QLQC feed network,both the wideband L...A wideband polarization reconfigurable dielectric resonator antenna excited by quasilumped quadrature coupler( QLQC) is proposed. By adjusting the value of varactor diode on the QLQC feed network,both the wideband LP and CP dielectric resonator antennas( DRA) modes can be achieved. By selecting a different feed port,left-and right-handed CP conversion can be realized.It is found that the 10 dB impedance bandwidth of the LP and CP modes are 10. 1% and 44. 9%,respectively.For the CP mode,a very wide 3 dB axial ratio bandwidth of 37. 7% can be obtained which is much larger than that of the microstrip patch counterpart( 3. 8%). It is worth mentioning that the wideband CP DRA has a stable broadside radiation pattern across the whole operating band where the boresight gain is larger than 3 dBi.展开更多
As a current analytical instrument for lipidomics profiling with high sensitivity, selectivity, and throughput, mass spectrometry (MS) has been widely used in the field of clinical medicine, nutrition, bromatology, bo...As a current analytical instrument for lipidomics profiling with high sensitivity, selectivity, and throughput, mass spectrometry (MS) has been widely used in the field of clinical medicine, nutrition, bromatology, botany and etc. During the routine use of shotgun- MS and high performance liquid chromatography-MS (HPLC-MS) in lipid analysis, an important problem to be solved is the defective repeatability and stability resulting from signal attenuation or drifts in LC-peak shape and retention time of MS platform. To remove or minimize the influence, extensively accepted and applied QC (quality control) samples must be performed. In this review, we emphasize the importance of the application of QC samples, which could 1) provide the ability to equilibrate the analytical platform at the beginning; 2) act as a quality assurance (QA) procedure during the analytical process; 3) perform signal correction in the data handling with the purpose of reducing analytical variation and improving the precision of quantitative analysis; 4) the data between different laboratories can be compared through the incorporation of particular QC samples-Standard Reference Material (SRM) 1950. In addition, we display 4 types and requirements of QC samples during quality control in lipidomics profiling. Lipidomics profiling based on MS strongly requires commonly accepted guidelines for quality control to perform routine, large-scale researches, so as to integrate data from different scientists for more information.展开更多
The effect of plant (rapeseed and grape seed) polyphenols on lipid metabolism of rat fed with high fat diet was studied. 30 rats were divided into 5 groups including group Z (basal diet), C (high fat diet without plan...The effect of plant (rapeseed and grape seed) polyphenols on lipid metabolism of rat fed with high fat diet was studied. 30 rats were divided into 5 groups including group Z (basal diet), C (high fat diet without plant polyphenol), S (high fat diet with rapeseed polyphenols), R (high fat diet with grape seed polyphenols) and F (combined with rapeseed and grape seed polyphenols). Levels of lipids including TAGs and PLs in rats were investigated by shotgun-electrospray ionization tandem mass spectrometry (shotgun-ESI-MS). Results showed that high fat diet would give rise to the total TAGs and decreased total phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) (p < 0.05) in group C, S, R and F, compared with group Z. Results also showed that supplementary with rapeseed polyphenols or grape seed polyphenols reduced total TAGs and increased total PC, PE and PS (p < 0.05) in group S, R and F, compared with group C. Grape seed polyphenols and rapeseed polyphenols had certain regulatory effect on metabolism diseases such as fatty liver.展开更多
We investigate the observational appearance of static and spherically symmetric hairy black holes in the framework of gravitational decoupling with the weak energy condition(WEC). Two types of thin illumination condit...We investigate the observational appearance of static and spherically symmetric hairy black holes in the framework of gravitational decoupling with the weak energy condition(WEC). Two types of thin illumination conditions are studied: spherical accretion and disk accretion. As the hairy parameter increases, the size of the photon sphere and photon rings in both models decreases, and the overall luminosity attenuation becomes more pronounced. In spherical accretion, the luminosity of infalling accretion is significantly lower than that of stationary accretion. In disk accretion the luminosity of the black hole is contributed by direct emission, the lensing ring and the photon ring. Employing four types of astrophysical disk luminosity model,we investigate the appearance of halos and note that their luminosities do not superimpose when the source is on or beyond the innermost stable circular orbit.展开更多
Increasing the efficiency of resource allocation is the basis and guarantee for boosting high-quality economic development.Based on the panel data of Chinese industrial enterprises and cities from 2008 to 2013,this pa...Increasing the efficiency of resource allocation is the basis and guarantee for boosting high-quality economic development.Based on the panel data of Chinese industrial enterprises and cities from 2008 to 2013,this paper studies the influence of infrastructure construction demand shocks represented by local government debt expansion on the efficiency of sectoral resource allocation from the perspective of sectoral linkage.According to the empirical findings,local government debt significantly reduces the resource allocation efficiency of manufacturing sector that is highly related to infrastructure construction.This conclusion is still tenable after the robustness test using the simulated local government debt as an instrumental variable.Further mechanism tests show that there are two reasons for the decline of the efficiency of resource allocation in manufacturing sector that is highly related to infrastructure construction.First,more product demands and investments brought by the expansion of local government debt flow to less productive enterprises in the sector.Second,resource misallocation reduces the probability of high-productivity enterprises entering the market and low-productivity enterprises exiting the market,and the effect is more prominent in cities with high dependence on state-owned enterprises and high pressure on officials to be promoted.According to this study,the performance management of local government debt should be further strengthened,and particular attention should be paid to the influence of local government debt on enterprise investment and financing crowding out and resource misallocation.展开更多
The basic physical properties of marine natural gas hydrate deposits are important to the understanding of seabed growth conditions, occurrence regularity, and occurrence environment of natural gas hydrates. A compreh...The basic physical properties of marine natural gas hydrate deposits are important to the understanding of seabed growth conditions, occurrence regularity, and occurrence environment of natural gas hydrates. A comprehensive analysis of the core samples of drilling pressure-holding hydrate deposits at a depth of 1310 m in the Shenhu area of the South China Sea was conducted. The experimental results indicate that the particle size in the hydrate sediment samples are mainly distributed in the range from 7.81 µm to 21.72 µm, and the average particle size decreases as the depth of the burial increases. The X-ray CT analytical images and surface characteristics SEM scan images suggest that the sediment is mostly silty clay. There are a large number of bioplastics in the sediment, and the crack inside the core may be areas of hydrate formation.展开更多
Marine natural gas hydrate has recently attracted global attention as a potential new clean energy source. Laboratory measurements of various physical properties of gas hydrate-bearing marine sediments can provide val...Marine natural gas hydrate has recently attracted global attention as a potential new clean energy source. Laboratory measurements of various physical properties of gas hydrate-bearing marine sediments can provide valuable information for developing efficient and safe extraction technology of natural gas hydrates. This study presents comprehensive measurement results and analysis of drilled hydrate-bearing sediments samples recovered from Qiongdongnan Basin in the South China Sea. The results show that the gas hydrate in the core samples is mainly methane hydrate with a methane content of approximately 95%, and the other components are ethane and carbon dioxide. The saturation of the samples fluctuates from 2%–60%, the porosity is approximately 38%–43%, and the water content is approximately 30%–50%, which indicate that high water saturation means that timely drainage should be paid attention to during hydrate extraction. In addition, the median diameter of the sediment samples is mainly distributed in the range of 15 to 34 µm, and attention should be paid to the prevention and control of sand production in the mining process. Moreover, the thermal conductivity is distributed in the range of 0.75 to 0.96 W/(m·K) as measured by the flat plate heat source method. The relatively low thermal conductivity of hydrates at this study site indicates that a combined approach is encouraged for natural gas production technologies. It is also found that clay flakes and fine particles are attached to the surface of large particles in large numbers. Such characteristics will lead to insufficient permeability during the production process.展开更多
基金Supported by the Key Research&Development Program of Shaanxi Province of China,No.2024SF-YBXM-447Institutional Foundation of The First Affiliated Hospital of Xi’an Jiaotong University,No.2022MS-07+1 种基金Fundamental Research Funds for the Central Universities,No.xzy022023068Natural Science Foundation of Shaanxi Province,No.2023-JC-QN-0814.
文摘BACKGROUND The magnetic compression technique has been used to establish an animal model of tracheoesophageal fistula(TEF),but the commonly shaped magnets present limitations of poor homogeneity of TEF and poor model control.We designed a Tshaped magnet system to overcome these problems and verified its effectiveness via animal experiments.AIM To investigate the effectiveness of a T-shaped magnet system for establishing a TEF model in beagle dogs.METHODS Twelve beagles were randomly assigned to groups in which magnets of the Tshaped scheme(study group,n=6)or normal magnets(control group,n=6)were implanted into the trachea and esophagus separately under gastroscopy.Operation time,operation success rate,and accidental injury were recorded.After operation,the presence and timing of cough and the time of magnet shedding were observed.Dogs in the control group were euthanized after X-ray and gastroscopy to confirm establishment of TEFs after coughing,and gross specimens of TEFs were obtained.Dogs in the study group were euthanized after X-ray and gastroscopy 2 wk after surgery,and gross specimens were obtained.Fistula size was measured in all animals,and then harvested fistula specimens were examined by hematoxylin and eosin(HE)and Masson trichrome staining.RESULTS The operation success rate was 100%for both groups.Operation time did not differ between the study group(5.25 min±1.29 min)and the control group(4.75 min±1.70 min;P=0.331).No bleeding,perforation,or unplanned magnet attraction occurred in any animal during the operation.In the early postoperative period,all dogs ate freely and were generally in good condition.Dogs in the control group had severe cough after drinking water at 6-9 d after surgery.X-ray indicated that the magnets had entered the stomach,and gastroscopy showed TEF formation.Gross specimens of TEFs from the control group showed the formation of fistulas with a diameter of 4.94 mm±1.29 mm(range,3.52-6.56 mm).HE and Masson trichrome staining showed scar tissue formation and hierarchical structural disorder at the fistulas.Dogs in the study group did not exhibit obvious coughing after surgery.X-ray examination 2 wk after surgery indicated fixed magnet positioning,and gastroscopy showed no change in magnet positioning.The magnets were removed using a snare under endoscopy,and TEF was observed.Gross specimens showed well-formed fistulas with a diameter of 6.11 mm±0.16 mm(range,5.92-6.36 mm),which exceeded that in the control group(P<0.001).Scar formation was observed on the internal surface of fistulas by HE and Masson trichrome staining,and the structure was more regular than that in the control group.CONCLUSION Use of the modified T-shaped magnet scheme is safe and feasible for establishing TEF and can achieve a more stable and uniform fistula size compared with ordinary magnets.Most importantly,this model offers better controllability,which improves the flexibility of follow-up studies.
基金support provided by the Institute of Energy,Hefei Comprehensive National Science Center (Grant No.21KZS216),ChinaCollaborative Innovation Project of Colleges and Universities of Anhui Province (Grant No.GXXT-2021-019),China+3 种基金the Open Fund of State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines (Grant No.SKLMRDPC19ZZ05),ChinaOpen Fund of National Local Joint Engineering Research Center for Safe and Accurate Coal Mining (EC2021002)Natural Science Research Project of University in Anhui (KJ2021ZD0050)Excellent Youth Project of Anhui Province (2022AH030086).
文摘Under the carbon neutrality goal,coal enterprises must seek breakthroughs from abandoned mines,develop new resources in the new era,turn problems into countermeasures,and participate in the carbon emissions market,for contributing to the accomplishment of the national strategic goal of carbon neutrality.To this end,we investigated the relevant national policies and regulations to clarify the boundaries disclosed by the carbon information of enterprises,understood the development direction of carbon storage in abandoned mines,and clarified the transformation and development of carbon storage in aban-doned mines.We made a few suggestions:(1)China should learn from its past experience and other countries to develop the energy industry with Chinese characteristics and reform the economic system.(2)Coal enterprises must actively respond to the national carbon information disclosure policy,clarify their own responsibilities and carbon emission boundaries.(3)It is necessary to proactively obtain advanced knowledge and plan carbon storage pathways for abandoned mines.(4)Devel-opment problems of coal enterprises should be deduced using cases.The'dual carbon'goals should be achieved steadily step-by-step.(5)Three measures,i.e.improving the existing resource structure,coordinating the information of abandoned mines,and promoting the cultivation of scientific and technological talents.
基金funded by National Natural Science Foundation of China(Grant No.U21A20274)We also gratefully acknowledge the support of the National Key R&D Program Key Special Project(Grant No.2021YFD1600103)+1 种基金Technology Innovation Project of Hubei Province(Grant No.2021BEC021)Agricultural Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(CAASASTIP-2013-OCRI).
文摘Food provides abundant nutrients for human beings, but also has sensory functions and physiological regulation.Lipids are the main components of food as well as the important structural and functional components of cells.Nevertheless, lipids are easily oxidized by different ways, such as thermal oxidation and air oxidation. Lipidoxidation has adverse effects on food quality and human health. Therefore, efforts should be made to reduce lipidoxidation and improve its stability. This review focuses on important knowledge about lipid oxidation, includingthe concept of lipids and lipid oxidation, the main pathways and mechanisms of lipid oxidation, factors affectinglipid oxidation, strategies to improve the stability of lipid oxidation, and the recent research progress of lipidoxidation in food science and nutritional health.
基金funded by Key Research Program of Frontier Sciences,CAS(ZDBS-LY-DQC012)the National Natural Science Foundation of China(41971321,41830108)+2 种基金XPCC Science and Technology Project(2022CB002-01)Open Fund of Key Laboratory of Oasis Eco-agriculture,XPCC(201801 and 202003)supported by Youth Innovation Promotion Association,CAS(Y2021047)。
文摘Verticillium wilt(VW)is a common soilborne disease of cotton.It occurs mainly in the seedling and bollopening stages and severely impairs the yield and quality of the fiber.Rapid and accurate identification and evaluation of VW severity(VWS)forms the basis of field cotton VW control,which has great significance to cotton production.Cotton VWS values are conventionally measured using in-field observations and laboratory test diagnoses,which require abundant time and professional expertise.Remote and proximal sensing using imagery and spectrometry have great potential for this purpose.In this study,we performed in situ investigations at three experimental sites in 2019 and 2021 and collected VWS values,in situ images,and spectra of 361 cotton canopies.To estimate cotton VWS values at the canopy scale,we developed two deep learning approaches that use in situ images and spectra,respectively.For the imagery-based method,given the high complexity of the in situ environment,we first transformed the task of healthy and diseased leaf recognition to the task of cotton field scene classification and then built a cotton field scenes(CFS)dataset with over 1000 images for each scene-unit type.We performed pretrained convolutional neural networks(CNNs)training and validation using the CFS dataset and then used the networks after training to classify scene units for each canopy.The results showed that the Dark Net-19 model achieved satisfactory performance in CFS classification and VWS values estimation(R^(2)=0.91,root-mean-square error(RMSE)=6.35%).For the spectroscopy-based method,we first designed a one-dimensional regression network(1D CNN)with four convolutional layers.After dimensionality reduction by sensitive-band selection and principal component analysis,we fitted the 1D CNN with varying numbers of principal components(PCs).The 1D CNN model with the top 20 PCs performed best(R^(2)=0.93,RMSE=5.77%).These deep learning-driven approaches offer the potential of assessing crop disease severity from spatial and spectral perspectives.
基金supported by the Opening Project of Hubei Key Laboratory of Lipid Chemistry and Nutrition(202106).
文摘DHA-enriched eggs have gained popularity due to their unique nutritional value,but their flavor can be challenging for some consumers to accept.The study analyzed the correlation of lipids and flavors in DHA-enriched egg yolks using comprehensive lipidomics and volatile compound analysis.The results showed that 411 lipids were detected in two egg yolk samples.Among them,148 lipid species,including 48 DHA-containing lipids,were significantly higher in DHA-enriched egg yolks than in Common ones(P<0.05).Furthermore,of the 24 volatile compounds detected,the contents of benzaldehyde,heptanal,hexanal,decanal and 2-nonanone in DHA-enriched egg yolks were significantly higher than in Common egg yolks(P<0.05).The“fishy”smell characteristic of DHAenriched egg yolks was mainly caused by volatile aldehydes,which may be produced through the hydrolysis of lipids in the egg yolk to free fatty acids and further oxidation.Analysis of the correlation network diagram revealed that phospholipids containing docosahexaenoic acid(DHA),linoleic acid,or oleic acid chains were the main contributors to the characteristic flavor of DHA-enriched egg yolks.Overall,this study explored the effect of different lipids on the flavor of DHA-enriched egg yolks and provided a theoretical basis for the production and improvement of DHA-enriched eggs.
文摘To investigate the impact of dietary supplementation of different omega-3 polyunsaturated fatty acids (n-3 PUFAs) resources on PUFAs enrichment in hen eggs, two supplemental materials, flaxseed and oil-extracted microalgal residue of heterotrophic Schizochytrium, were added to the diet of laying hens in 3 groups. Results showed that supplementation with flaxseed and Schizochytrium residue gave rise to the increased, but different n-3 PUFAs levels in egg yolk, mainly α-linolenic acid (ALA) and docosahexaenoic acid (DHA). The ratio of n-6/n-3 PUFAs was reduced in all groups. After 14 days feeding of supplied PUFAs resources, n-3 PUFAs contents reached a plateau, and then remained constant during further supplementation in 3 experimental groups. Both the highest ALA level and DHA level were achieved in flaxseed group and microalgae group, reaching up to 353.69 (±68.15) mg/egg and 301.41 (± 26.76) mg/egg respectively. Moreover, the n-3 PUFAs enrichment efficiency was relatively low in flaxseed group when compared to other 2 groups. Laying rates of hens before entering peak production period could be improved by adding flaxseed but was not obviously affected by Schizochytrium residue. The egg weight, on the other hand, had no relationship with dietary supplementation. Thus, supplementation of flaxseed or Schizochytrium residue into standard feed offers an alternative choice for the production of n-3 PUFAs enriched eggs.
基金Project supported by the National Natural Science Foundation of China(Nos.11725207,12021002,and 12072226)。
文摘This paper studies the contact vibration problem of an elastic half-space coated with functionally graded materials(FGMs)subject to a rigid spherical punch.A static force superimposing a dynamic time-harmonic force acts on the rigid spherical punch.Firstly,we give the static contact problem of FGMs by a least-square fitting approach.Next,the dynamic contact pressure is solved by employing the perturbation method.Lastly,the dynamic contact stiffness with different dynamic contact displacement conditions is derived for the FGM coated half-space.The effects of the gradient index,coating thickness,internal friction,and punch radius on the dynamic contact stiffness factor are discussed in detail.
基金Supported by the National Natural Science Foundation of China(61401025)
文摘A polysilicon separated CMOS Schottky barrier diode is designed and tested in this study.By replacing the shallow trench isolation(STI)of a ploy ring,the series resistances of Schottky diodes are reduced,leading to an improvement in cut-off frequencies.The device structure is detailed and a device model is developed.Our analysis on the device shows that the cut-off frequency increases with the decreasing of the Schottky contact area.Based on this observation,the Schottky contact area is set to0.38×0.38μm^2,which is the minimum contact diffusion area allowed by the process flow.The distance between the anode and the cathode is also discussed.Diodes with different dimensions are fabricated and measured.Through extensive measurements,the optimum dimensions are obtained.Bondpads with a reduced area are used to improve the measurement accuracy.The measurement results show that these diodes can achieve a cut-off frequency of 1.5 THz.Thus,it is possible to use these diodes in THz detection.
基金Supported by the National Natural Science Foundation of China(61771055,61527805)
文摘A wideband polarization reconfigurable dielectric resonator antenna excited by quasilumped quadrature coupler( QLQC) is proposed. By adjusting the value of varactor diode on the QLQC feed network,both the wideband LP and CP dielectric resonator antennas( DRA) modes can be achieved. By selecting a different feed port,left-and right-handed CP conversion can be realized.It is found that the 10 dB impedance bandwidth of the LP and CP modes are 10. 1% and 44. 9%,respectively.For the CP mode,a very wide 3 dB axial ratio bandwidth of 37. 7% can be obtained which is much larger than that of the microstrip patch counterpart( 3. 8%). It is worth mentioning that the wideband CP DRA has a stable broadside radiation pattern across the whole operating band where the boresight gain is larger than 3 dBi.
文摘As a current analytical instrument for lipidomics profiling with high sensitivity, selectivity, and throughput, mass spectrometry (MS) has been widely used in the field of clinical medicine, nutrition, bromatology, botany and etc. During the routine use of shotgun- MS and high performance liquid chromatography-MS (HPLC-MS) in lipid analysis, an important problem to be solved is the defective repeatability and stability resulting from signal attenuation or drifts in LC-peak shape and retention time of MS platform. To remove or minimize the influence, extensively accepted and applied QC (quality control) samples must be performed. In this review, we emphasize the importance of the application of QC samples, which could 1) provide the ability to equilibrate the analytical platform at the beginning; 2) act as a quality assurance (QA) procedure during the analytical process; 3) perform signal correction in the data handling with the purpose of reducing analytical variation and improving the precision of quantitative analysis; 4) the data between different laboratories can be compared through the incorporation of particular QC samples-Standard Reference Material (SRM) 1950. In addition, we display 4 types and requirements of QC samples during quality control in lipidomics profiling. Lipidomics profiling based on MS strongly requires commonly accepted guidelines for quality control to perform routine, large-scale researches, so as to integrate data from different scientists for more information.
文摘The effect of plant (rapeseed and grape seed) polyphenols on lipid metabolism of rat fed with high fat diet was studied. 30 rats were divided into 5 groups including group Z (basal diet), C (high fat diet without plant polyphenol), S (high fat diet with rapeseed polyphenols), R (high fat diet with grape seed polyphenols) and F (combined with rapeseed and grape seed polyphenols). Levels of lipids including TAGs and PLs in rats were investigated by shotgun-electrospray ionization tandem mass spectrometry (shotgun-ESI-MS). Results showed that high fat diet would give rise to the total TAGs and decreased total phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) (p < 0.05) in group C, S, R and F, compared with group Z. Results also showed that supplementary with rapeseed polyphenols or grape seed polyphenols reduced total TAGs and increased total PC, PE and PS (p < 0.05) in group S, R and F, compared with group C. Grape seed polyphenols and rapeseed polyphenols had certain regulatory effect on metabolism diseases such as fatty liver.
基金supported by the National Natural Science Foundation of China (NSFC) with grant nos 12175212, 12275183 and 12275184。
文摘We investigate the observational appearance of static and spherically symmetric hairy black holes in the framework of gravitational decoupling with the weak energy condition(WEC). Two types of thin illumination conditions are studied: spherical accretion and disk accretion. As the hairy parameter increases, the size of the photon sphere and photon rings in both models decreases, and the overall luminosity attenuation becomes more pronounced. In spherical accretion, the luminosity of infalling accretion is significantly lower than that of stationary accretion. In disk accretion the luminosity of the black hole is contributed by direct emission, the lensing ring and the photon ring. Employing four types of astrophysical disk luminosity model,we investigate the appearance of halos and note that their luminosities do not superimpose when the source is on or beyond the innermost stable circular orbit.
基金Major Project of the National Social Science Fund of China"A Study on the Division of Inter-Governmental Power and Expenditure Responsibilities in China"(16ZDA065).The authors are very grateful to the anonymous reviewers for their constructive comments,and take sole responsibility for the paper.
文摘Increasing the efficiency of resource allocation is the basis and guarantee for boosting high-quality economic development.Based on the panel data of Chinese industrial enterprises and cities from 2008 to 2013,this paper studies the influence of infrastructure construction demand shocks represented by local government debt expansion on the efficiency of sectoral resource allocation from the perspective of sectoral linkage.According to the empirical findings,local government debt significantly reduces the resource allocation efficiency of manufacturing sector that is highly related to infrastructure construction.This conclusion is still tenable after the robustness test using the simulated local government debt as an instrumental variable.Further mechanism tests show that there are two reasons for the decline of the efficiency of resource allocation in manufacturing sector that is highly related to infrastructure construction.First,more product demands and investments brought by the expansion of local government debt flow to less productive enterprises in the sector.Second,resource misallocation reduces the probability of high-productivity enterprises entering the market and low-productivity enterprises exiting the market,and the effect is more prominent in cities with high dependence on state-owned enterprises and high pressure on officials to be promoted.According to this study,the performance management of local government debt should be further strengthened,and particular attention should be paid to the influence of local government debt on enterprise investment and financing crowding out and resource misallocation.
文摘The basic physical properties of marine natural gas hydrate deposits are important to the understanding of seabed growth conditions, occurrence regularity, and occurrence environment of natural gas hydrates. A comprehensive analysis of the core samples of drilling pressure-holding hydrate deposits at a depth of 1310 m in the Shenhu area of the South China Sea was conducted. The experimental results indicate that the particle size in the hydrate sediment samples are mainly distributed in the range from 7.81 µm to 21.72 µm, and the average particle size decreases as the depth of the burial increases. The X-ray CT analytical images and surface characteristics SEM scan images suggest that the sediment is mostly silty clay. There are a large number of bioplastics in the sediment, and the crack inside the core may be areas of hydrate formation.
基金This work was supported by the National Natural Science Foundation of China (Grant No. U19B2005).
文摘Marine natural gas hydrate has recently attracted global attention as a potential new clean energy source. Laboratory measurements of various physical properties of gas hydrate-bearing marine sediments can provide valuable information for developing efficient and safe extraction technology of natural gas hydrates. This study presents comprehensive measurement results and analysis of drilled hydrate-bearing sediments samples recovered from Qiongdongnan Basin in the South China Sea. The results show that the gas hydrate in the core samples is mainly methane hydrate with a methane content of approximately 95%, and the other components are ethane and carbon dioxide. The saturation of the samples fluctuates from 2%–60%, the porosity is approximately 38%–43%, and the water content is approximately 30%–50%, which indicate that high water saturation means that timely drainage should be paid attention to during hydrate extraction. In addition, the median diameter of the sediment samples is mainly distributed in the range of 15 to 34 µm, and attention should be paid to the prevention and control of sand production in the mining process. Moreover, the thermal conductivity is distributed in the range of 0.75 to 0.96 W/(m·K) as measured by the flat plate heat source method. The relatively low thermal conductivity of hydrates at this study site indicates that a combined approach is encouraged for natural gas production technologies. It is also found that clay flakes and fine particles are attached to the surface of large particles in large numbers. Such characteristics will lead to insufficient permeability during the production process.