The accurate and efficient analysis of anisotropic heat conduction problems in complex composites is crucial for structural design and performance evaluation. Traditional numerical methods, such as the finite element ...The accurate and efficient analysis of anisotropic heat conduction problems in complex composites is crucial for structural design and performance evaluation. Traditional numerical methods, such as the finite element method(FEM), often face a trade-off between calculation accuracy and efficiency. In this paper, we propose a quasi-smooth manifold element(QSME) method to address this challenge, and provide the accurate and efficient analysis of two-dimensional(2D) anisotropic heat conduction problems in composites with complex geometry. The QSME approach achieves high calculation precision by a high-order local approximation that ensures the first-order derivative continuity.The results demonstrate that the QSME method is robust and stable, offering both high accuracy and efficiency in the heat conduction analysis. With the same degrees of freedom(DOFs), the QSME method can achieve at least an order of magnitude higher calculation accuracy than the traditional FEM. Additionally, under the same level of calculation error, the QSME method requires 10 times fewer DOFs than the traditional FEM. The versatility of the proposed QSME method extends beyond anisotropic heat conduction problems in complex composites. The proposed QSME method can also be applied to other problems, including fluid flows, mechanical analyses, and other multi-field coupled problems, providing accurate and efficient numerical simulations.展开更多
Heavy metal distribution in mining areas has always been a hot research topic due to the special environment of these areas. This study aims to explore the impact of heavy metal pollution on soils and crops in the stu...Heavy metal distribution in mining areas has always been a hot research topic due to the special environment of these areas. This study aims to explore the impact of heavy metal pollution on soils and crops in the study area, ensure the safety of local crops and the health of local residents, and provide a basis for the subsequent environmental restoration and the prevention and control of environmental pollution. Based on the analysis of the heavy metal concentrations in local soils and crops, the study investigated the spatial distribution, pollution degrees, and potential ecological risks of heavy metals in the farmland of a mining area in the southeastern Nanyang Basin, Henan province, China explored the sources of heavy metals and assessed the health risks caused by crop intake. The results of this study are as follows. The root soils of crops in the study area suffered heavy metal pollution to varying degrees. The degree of heavy metal pollution in maize fields is higher than that in wheat fields, and both types of fields suffer the most severe Cd pollution. Moreover, the root soils of different crops suffer compound pollution.The root soils in the maize fields suffer severe compound pollution at some sampling positions, whose distribution is similar to that of the mining area. Cd poses the highest potential ecological risks among all heavy metals, and the study area mainly suffers low and moderate comprehensive potential ecological risks. The principal component analysis(PCA) shows that the distribution of Zn, Cd, Pb, and As in soils of the study area is mainly affected by anthropogenic factors such as local mining activities;the distribution of Cr and Ni is primarily controlled by the local geological background;the distribution of Hg is mainly affected by local vehicle exhaust emissions, and the distribution of Cu is influenced by both human activities and the geological background. Different cereal crops in the study area are polluted with heavy metals dominated by Cd and Ni to varying degrees, especially wheat. As indicated by the health risk assessment results, the intake of maize in the study area does not pose significant human health risks;however, Cu has high risks to human health, and the compound heavy metal pollution caused by the intake of wheat in the study area poses risks to the health of both adults and children. Overall, the soils and crops in the study area suffer a high degree of heavy metal pollution, for which mining activities may be the main reason.展开更多
The research on high-performance vector control of permanent magnet synchronous motor(PMSM)drive system plays an extremely important role in electrical drive system.To further improve the speed control performance of ...The research on high-performance vector control of permanent magnet synchronous motor(PMSM)drive system plays an extremely important role in electrical drive system.To further improve the speed control performance of the system,a fast non-singular end sliding mode(FNTSM)surface function based on traditional NTSM control is developed.The theoretical analysis proves that the FNTSM surface function has a faster dynamic response and more finite-time convergence.In addition,for the self-vibration problem caused by high sliding mode switching gain,an FNTSM control method with anti-disturbance capability was designed based on the linear disturbance observer(DO),i.e.the FNTSMDO method was employed to devise the PMSM speed regulator.The comparative simulation and experiment results with traditional PI control and NTSM control methods indicate that the FNTSMDO method could improve the dynamic performance and anti-interference of the system.展开更多
Aluminum high pressure die casting(HPDC)technology has evolved in the past decades,enabling stronger and larger one-piece casting with significant part consolidation.It also offers a higher design freedom for more mas...Aluminum high pressure die casting(HPDC)technology has evolved in the past decades,enabling stronger and larger one-piece casting with significant part consolidation.It also offers a higher design freedom for more mass-efficient thin-walled body structures.For body structures that require excellent ductility and fracture toughness to be joined with steel sheet via self-piercing riveting(for instance,shock towers and hinge pillars,etc.),a costly T7 heat treatment comprising a solution heat treatment at elevated temperatures(450℃-500℃)followed by an over-ageing heat treatment is needed to optimize microstructure for meeting product requirement.To enable cost-efficient mass production of HPDC body structures,it is important to eliminate the expensive T7 heat treatment without sacrificing mechanical properties.Optimizing die cast alloy chemistry is a potential solution to improve fracture toughness and ductility of the HPDC components.The present study intends to tailor the Mg and Cu additions for a new Al-Si-Cr type die casting alloy(registered as A379 with The Aluminum Association,USA)to achieve the desired tensile properties without using T7 heat treatment.It was found that Cu addition should be avoided,as it is not effective in enhancing strength while degrades tensile ductility.Mg addition is very effective in improving strength and has minor impact on tensile ductility.The investigated Al-Si-Cr alloy with a nominal composition of Al-8.5wt.%Si-0.3wt.%Cr-0.2wt.%Fe shows comparable tensile properties with the T7 treated AlSi10MnMg alloy which is currently used for manufacturing shock towers and hinge pillars.展开更多
The third paragraph in Sec.IV REGENERATIVE AMPLIFICATION erroneously states“In other words,the distribution of spectral components is time-dependent,and the spectral distortion in the amplification process will not c...The third paragraph in Sec.IV REGENERATIVE AMPLIFICATION erroneously states“In other words,the distribution of spectral components is time-dependent,and the spectral distortion in the amplification process will not change the time-domain shape.”展开更多
Neurotrophic factors,particularly nerve growth factor,enhance neuronal regeneration.However,the in vivo applications of nerve growth factor are largely limited by its intrinsic disadvantages,such as its short biologic...Neurotrophic factors,particularly nerve growth factor,enhance neuronal regeneration.However,the in vivo applications of nerve growth factor are largely limited by its intrinsic disadvantages,such as its short biological half-life,its contribution to pain response,and its inability to cross the blood-brain barrier.Considering that let-7(human miRNA)targets and regulates nerve growth factor,and that let-7 is a core regulator in peripheral nerve regeneration,we evaluated the possibilities of let-7 application in nerve repair.In this study,anti-let-7a was identified as the most suitable let-7 family molecule by analyses of endogenous expression and regulatory relationship,and functional screening.Let-7a antagomir demonstrated biosafety based on the results of in vivo safety assessments and it entered into the main cell types of the sciatic nerve,including Schwann cells,fibroblasts and macrophages.Use of hydrogel effectively achieved controlled,localized,and sustained delivery of let-7a antagomir.Finally,let-7a antagomir was integrated into chitosan conduit to construct a chitosan-hydrogel scaffold tissue-engineered nerve graft,which promoted nerve regeneration and functional recovery in a rat model of sciatic nerve transection.Our study provides an experimental basis for potential in vivo application of let-7a.展开更多
Due to the low porosity and low permeability in unconventional reservoirs,a large amount of crude oil is trapped in micro-to nano-sized pores and throats,which leads to low oil recovery.Nanofluids have great potential...Due to the low porosity and low permeability in unconventional reservoirs,a large amount of crude oil is trapped in micro-to nano-sized pores and throats,which leads to low oil recovery.Nanofluids have great potential to enhance oil recovery(EOR)in low permeability reservoirs.In this work,the regulating ability of a nanofluid at the oil/water/solid three-phase interface was explored.The results indicated that the nanofluid reduced the oil/water interfacial tension by two orders of magnitude,and the expansion modulus of oil/water interface was increased by 77% at equilibrium.In addition,the solid surface roughness was reduced by 50%,and the three-phase contact angle dropped from 135(oil-wet)to 48(water-wet).Combining the displacement experiments using a 2.5D reservoir micromodel and a microchannel model,the remaining oil mobilization and migration processes in micro-to nano-scale pores and throats were visualized.It was found that the nanofluid dispersed the remaining oil into small oil droplets and displaced them via multiple mechanisms in porous media.Moreover,the high strength interface film formed by the nanofluid inhibited the coalescence of oil droplets and improved the flowing ability.These results help to understand the EOR mechanisms of nanofluids in low permeability reservoirs from a visual perspective.展开更多
A rate-dependent constitutive model for saturated frozen soil is vital in frozen soil mechanics,especially when simultaneously describing the nonlinearity,dilatancy and strain-softening characteristics.The distributio...A rate-dependent constitutive model for saturated frozen soil is vital in frozen soil mechanics,especially when simultaneously describing the nonlinearity,dilatancy and strain-softening characteristics.The distribution of the non-uniform strain rate of saturated frozen soil at the meso-scale due to the local icecementation breakage is described by a newly binary-medium-based homogenization equation.Based on the field-equation-based approach of the meso-mechanics theory,the interaction expression of the strain rate at macro-and meso-scale is derived,which can give the strain rate concentration tensor at different crushed degrees.With the thermodynamics and empirical assumption,a breakage ratio in the rate-dependent form is determined.This overcomes the limitations of the existing binary-medium-based models that are difficult to simulate rate-dependent mechanical response.Based on these assumptions,a newly binary-medium-based rate-dependent model is proposed considering both the ice bond breakage and material composition characteristics of saturated frozen soil.The proposed constitutive model has been validated by the test results on frozen soils with different temperatures and strain rates.展开更多
Molecularly imprinted polymers (MIPs) have great potential as adsorbents for selective adsorption and separation of nucleoside compounds,but effectively enhancing the affinity of recognition sites by adjusting the for...Molecularly imprinted polymers (MIPs) have great potential as adsorbents for selective adsorption and separation of nucleoside compounds,but effectively enhancing the affinity of recognition sites by adjusting the forces between template molecules and functional monomers remains an important challenge.In this work,a surface imprinting strategy was used to construct bowl-shaped molecularly imprinted composite sorbents (BHPN@MIPs) based on polydopamine (PDA) particles and have achieved selective separation and purification of 2'-deoxyadenosine (dA).Where by the base complementary pairing interaction of the combined template molecule d A and the pyrimidine functional monomer can enhance the preassembly force,and the hydrophilic bowl-shaped PDA can provide a larger storage space contact efficiency of d A in the test solution,causing the site utilization much higher and improving the kinetic adsorption performance.The equilibrium adsorption time and maximum adsorption capacity of60 min and 328.45μmol·g^(-1)were observed by static adsorption experiments,and the selectivity experimental results showed an imprinting factor IF of 1.30.After four adsorption–desorption cycles,the initial adsorption equilibrium adsorption capacity of BHPN@MIPs still retained 91.14%.By evaluating the selective adsorption of d A in spiked human serum solutions,BHPN@MIPs can be used to selectively enrich and analyze target d A in complex biological samples.展开更多
Optical vortices with tunable polarization states and topological charges are widely investigated in various physical systems and practical devices for high-capacity optical communication.However,this kind of structur...Optical vortices with tunable polarization states and topological charges are widely investigated in various physical systems and practical devices for high-capacity optical communication.However,this kind of structured light beams is usually generated using several polarization and spatial phase devices,which decreases the configurability of optical systems.Here,we have designed a kind of polarized optical multi-vortices generator based on the Stokes-Mueller formalism and cross-phase modulation.In our scheme,multi-channel generation of polarized vortex beams can be realized through a single optical element and a single-input Gaussian beam.The polarization states and orbital angular momentum of the generated light beams are all-optically controllable.Furthermore,the proposed polarized optical multi-vortices generator has also been demonstrated experimentally through one-step holographic recording in an azobenzene liquid-crystalline film and the experimental results agree with theoretical analysis.展开更多
BACKGROUND Growth differentiation factor 15(GDF-15)has been explored as a potential biomarker for various inflammatory diseases and cardiovascular events.This study aimed to assess the predictive role of GDF-15 levels...BACKGROUND Growth differentiation factor 15(GDF-15)has been explored as a potential biomarker for various inflammatory diseases and cardiovascular events.This study aimed to assess the predictive role of GDF-15 levels in cardiovascular events and all-cause mortality,considering traditional risk factors and other biomarkers.METHODS A prospective study was conducted and 3699 patients with stable coronary artery disease(CAD)were enrolled into the research.Baseline GDF-15 levels were measured.Median follow-up was 3.1 years during the study.We analyzed clinical variables and several biomarkers.Multivariable Cox regression analysis was performed to evaluate prognostic performance of GDF-15 levels in predicting myocardial infarction(MI),heart failure,stroke,cardiovascular death,and non-cardiovascular death.RESULTS Baseline GDF-15 levels for 3699 patients were grouped by quartile(≤1153,1153-1888,1888-3043,>3043 ng/L).Higher GDF-15 levels were associated with older age,male gender,history of hypertension,and elevated levels of N-terminal pro Btype natriuretic peptide(NT-pro BNP),soluble suppression of tumorigenesis-2(sST2),and creatine(each with P<0.001).Adjusting for established risk factors and biomarkers in Cox proportional hazards models,a 1 standard deviation(SD)increase in GDF-15 was associated with elevated risk of clinical events[hazard ratio(HR)=2.18,95%confidence interval(CI):(1.52-3.11)],including:MI[HR=2.8395%CI:(1.03-7.74)],heart failure[HR=2.7195%CI:(1.18-6.23)],cardiovascular and non-cardiovascular death[HR=2.48,95%CI(1.49-4.11)]during the median follow up of 3.1 years.CONCLUSIONS Higher levels of GDF-15 consistently provides prognostic information for cardiovascular events and all cause death,independent of clinical risk factors and other biomarkers.GDF-15 could be considered as a valuable addition to future risk prediction model in secondary prevention for predicting clinical events in patient with stable CAD.展开更多
BACKGROUND Benign lymphoepithelial cyst(BLEC)of the parotid gland is a rare benign embryonic-dysplastic cystic tumor in the anterolateral neck that occurs most commonly in human immunodeficiency virus(HIV)-positive ad...BACKGROUND Benign lymphoepithelial cyst(BLEC)of the parotid gland is a rare benign embryonic-dysplastic cystic tumor in the anterolateral neck that occurs most commonly in human immunodeficiency virus(HIV)-positive adults and rarely in non-acquired immune deficiency syndrome patients.The main presentation is a slow-growing,painless mass,and secondary infection may cause acute inflammatory symptoms.CASE SUMMARY A 44-year-old Chinese male patient presented with a 1-year history of a mass in the left side of the neck.On physical examination,a mass similar in size and shape to a quail egg was found in the left parotid gland.The mass was tough,without tenderness,and easily moveable.The results of HIV tests,including antibody and nucleic acid tests and CD4+T cell examination,were negative.Imaging examination revealed a left parotid gland mass.The patient underwent surgical treatment,and BLEC was diagnosed based on postoperative pathology.After 2years of follow-up,the patient survived well without related discomfort.CONCLUSION The detailed characteristics of a BLEC in a patient without HIV infection contribute to an improved understanding of this rare disease.展开更多
Broadband low-coherence light is considered to be an effective way to suppress laser plasma instability.Recent studies have demonstrated the ability of low-coherence laser facilities to reduce back-scattering during b...Broadband low-coherence light is considered to be an effective way to suppress laser plasma instability.Recent studies have demonstrated the ability of low-coherence laser facilities to reduce back-scattering during beam–target coupling.However,to ensure simultaneous low coherence and high energy,complex spectral modulation methods and amplification routes have to be adopted.In this work,we propose the use of a random fiber laser(RFL)as the seed source.The spectral features of this RFL can be carefully tailored to provide a good match with the gain characteristics of the laser amplification medium,thus enabling efficient amplification while maintaining low coherence.First,a theoretical model is constructed to give a comprehensive description of the output characteristics of the spectrum-tailored RFL,after which the designed RFL is experimentally realized as a seed source.Through precise pulse shaping and efficient regenerative amplification,a shaped random laser pulse output of 28 mJ is obtained,which is the first random laser system with megawatt-class peak power that is able to achieve low coherence and efficient spectrum-conformal regenerative amplification.展开更多
BACKGROUND Gastric cancer(GC)is one of the most common malignant tumors with poor prognosis in terms of advanced stage.However,the survival-associated biomarkers for GC remains unclear.AIM To investigate the potential...BACKGROUND Gastric cancer(GC)is one of the most common malignant tumors with poor prognosis in terms of advanced stage.However,the survival-associated biomarkers for GC remains unclear.AIM To investigate the potential biomarkers of the prognosis of patients with GC,so as to provide new methods and strategies for the treatment of GC.METHODS RNA sequencing data from The Cancer Genome Atlas(TCGA)database of STAD tumors,and microarray data from Gene Expression Omnibus(GEO)database(GSE19826,GSE79973 and GSE29998)were obtained.The differentially expressed genes(DEGs)between GC patients and health people were picked out using R software(x644.1.3).The intersections were underwent between the above obtained co-expression of differential genes(co-DEGs)and the DEGs of GC from Gene Expression Profiling Interactive Analysis database,and Gene Ontology(GO)analysis,Kyoto Encyclopedia of Gene and Genome(KEGG)pathway analysis,Gene Set Enrichment Analysis(GSEA),Protein-protein Interaction(PPI)analysis and Kaplan-Meier Plotter survival analysis were performed on these DEGs.Using Immunohistochemistry(IHC)database of Human Protein Atlas(HPA),we verified the candidate Hub genes.RESULTS With DEGs analysis,there were 334 co-DEGs,including 133 up-regulated genes and 201 down-regulated genes.GO enrichment analysis showed that the co-DEGs were involved in biological process,cell composition and molecular function pathways.KEGG enrichment analysis suggested the co-DEGs pathways were mainly enriched in ECM-receptor interaction,protein digestion and absorption pathways,etc.GSEA pathway analysis showed that co-DEGs mainly concentrated in cell cycle progression,mitotic cell cycle and cell cycle pathways,etc.PPI analysis showed 84 nodes and 654 edges for the co-DEGs.The survival analysis illustrated 11 Hub genes with notable significance for prognosis of patients were screened.Furtherly,using IHC database of HPA,we confirmed the above candidate Hub genes,and 10 Hub genes that associated with prognosis of GC were identified,namely BGN,CEP55,COL1A2,COL4A1,FZD2,MAOA,PDGFRB,SPARC,TIMP1 and VCAN.CONCLUSION The 10 Hub genes may be the potential biomarkers for predicting the prognosis of GC,which can provide new strategies and methods for the diagnosis and treatment of GC.展开更多
目的探讨生物反馈电刺激联合心理干预对产后女性性功能障碍(FSD)的治疗效果。方法选取2014年1月-2016年12月河北医科大学第一医院盆底康复中心收治的产后42 d FSD患者400例作为研究对象,根据随机信封抽签原则分为观察组与对照组各200例...目的探讨生物反馈电刺激联合心理干预对产后女性性功能障碍(FSD)的治疗效果。方法选取2014年1月-2016年12月河北医科大学第一医院盆底康复中心收治的产后42 d FSD患者400例作为研究对象,根据随机信封抽签原则分为观察组与对照组各200例,对照组给予一般产后健康教育,观察组给予生物反馈电刺激联合心理干预,持续观察3个月。结果观察组治疗后盆底肌力改善率优于对照组(P<0.05)。观察组与对照组治疗后的膀胱初感充盈量与最大充盈量均高于治疗前(P<0.05),同时治疗后观察组的膀胱初感充盈量与最大充盈量高于对照组(P<0.05)。治疗后发现观察组患者的焦虑与抑郁评分比对照组患者低(P<0.05),同时治疗后观察组的焦虑和抑郁评分也低于对照组(P<0.05)。治疗后观察组的1个月性生活次数与性高潮频率都高于对照组(P<0.05),且观察组的性交痛发生率低于对照组(P<0.05)。结论生物反馈电刺激联合心理干预治疗FSD能有效改善膀胱的生物学功能,提高盆底肌力,有效缓解患者的焦虑与抑郁程度,从而提高性生活质量。展开更多
基金Project supported by the National Natural Science Foundation of China (Nos. 12102043, 12072375U2241240)the Natural Science Foundation of Hunan Province of China (Nos. 2023JJ40698 and 2021JJ40710)。
文摘The accurate and efficient analysis of anisotropic heat conduction problems in complex composites is crucial for structural design and performance evaluation. Traditional numerical methods, such as the finite element method(FEM), often face a trade-off between calculation accuracy and efficiency. In this paper, we propose a quasi-smooth manifold element(QSME) method to address this challenge, and provide the accurate and efficient analysis of two-dimensional(2D) anisotropic heat conduction problems in composites with complex geometry. The QSME approach achieves high calculation precision by a high-order local approximation that ensures the first-order derivative continuity.The results demonstrate that the QSME method is robust and stable, offering both high accuracy and efficiency in the heat conduction analysis. With the same degrees of freedom(DOFs), the QSME method can achieve at least an order of magnitude higher calculation accuracy than the traditional FEM. Additionally, under the same level of calculation error, the QSME method requires 10 times fewer DOFs than the traditional FEM. The versatility of the proposed QSME method extends beyond anisotropic heat conduction problems in complex composites. The proposed QSME method can also be applied to other problems, including fluid flows, mechanical analyses, and other multi-field coupled problems, providing accurate and efficient numerical simulations.
基金jointly funded by National Natural Science Foundation of China (41877398)project of the China Geological Survey (DD20221773)。
文摘Heavy metal distribution in mining areas has always been a hot research topic due to the special environment of these areas. This study aims to explore the impact of heavy metal pollution on soils and crops in the study area, ensure the safety of local crops and the health of local residents, and provide a basis for the subsequent environmental restoration and the prevention and control of environmental pollution. Based on the analysis of the heavy metal concentrations in local soils and crops, the study investigated the spatial distribution, pollution degrees, and potential ecological risks of heavy metals in the farmland of a mining area in the southeastern Nanyang Basin, Henan province, China explored the sources of heavy metals and assessed the health risks caused by crop intake. The results of this study are as follows. The root soils of crops in the study area suffered heavy metal pollution to varying degrees. The degree of heavy metal pollution in maize fields is higher than that in wheat fields, and both types of fields suffer the most severe Cd pollution. Moreover, the root soils of different crops suffer compound pollution.The root soils in the maize fields suffer severe compound pollution at some sampling positions, whose distribution is similar to that of the mining area. Cd poses the highest potential ecological risks among all heavy metals, and the study area mainly suffers low and moderate comprehensive potential ecological risks. The principal component analysis(PCA) shows that the distribution of Zn, Cd, Pb, and As in soils of the study area is mainly affected by anthropogenic factors such as local mining activities;the distribution of Cr and Ni is primarily controlled by the local geological background;the distribution of Hg is mainly affected by local vehicle exhaust emissions, and the distribution of Cu is influenced by both human activities and the geological background. Different cereal crops in the study area are polluted with heavy metals dominated by Cd and Ni to varying degrees, especially wheat. As indicated by the health risk assessment results, the intake of maize in the study area does not pose significant human health risks;however, Cu has high risks to human health, and the compound heavy metal pollution caused by the intake of wheat in the study area poses risks to the health of both adults and children. Overall, the soils and crops in the study area suffer a high degree of heavy metal pollution, for which mining activities may be the main reason.
基金supported in part by the National Natural Science Foundation of China under Grant 51507188Doctoral Research Startup Foundation of Hubei University of Technology under Grant XJ2021000302。
文摘The research on high-performance vector control of permanent magnet synchronous motor(PMSM)drive system plays an extremely important role in electrical drive system.To further improve the speed control performance of the system,a fast non-singular end sliding mode(FNTSM)surface function based on traditional NTSM control is developed.The theoretical analysis proves that the FNTSM surface function has a faster dynamic response and more finite-time convergence.In addition,for the self-vibration problem caused by high sliding mode switching gain,an FNTSM control method with anti-disturbance capability was designed based on the linear disturbance observer(DO),i.e.the FNTSMDO method was employed to devise the PMSM speed regulator.The comparative simulation and experiment results with traditional PI control and NTSM control methods indicate that the FNTSMDO method could improve the dynamic performance and anti-interference of the system.
文摘Aluminum high pressure die casting(HPDC)technology has evolved in the past decades,enabling stronger and larger one-piece casting with significant part consolidation.It also offers a higher design freedom for more mass-efficient thin-walled body structures.For body structures that require excellent ductility and fracture toughness to be joined with steel sheet via self-piercing riveting(for instance,shock towers and hinge pillars,etc.),a costly T7 heat treatment comprising a solution heat treatment at elevated temperatures(450℃-500℃)followed by an over-ageing heat treatment is needed to optimize microstructure for meeting product requirement.To enable cost-efficient mass production of HPDC body structures,it is important to eliminate the expensive T7 heat treatment without sacrificing mechanical properties.Optimizing die cast alloy chemistry is a potential solution to improve fracture toughness and ductility of the HPDC components.The present study intends to tailor the Mg and Cu additions for a new Al-Si-Cr type die casting alloy(registered as A379 with The Aluminum Association,USA)to achieve the desired tensile properties without using T7 heat treatment.It was found that Cu addition should be avoided,as it is not effective in enhancing strength while degrades tensile ductility.Mg addition is very effective in improving strength and has minor impact on tensile ductility.The investigated Al-Si-Cr alloy with a nominal composition of Al-8.5wt.%Si-0.3wt.%Cr-0.2wt.%Fe shows comparable tensile properties with the T7 treated AlSi10MnMg alloy which is currently used for manufacturing shock towers and hinge pillars.
文摘The third paragraph in Sec.IV REGENERATIVE AMPLIFICATION erroneously states“In other words,the distribution of spectral components is time-dependent,and the spectral distortion in the amplification process will not change the time-domain shape.”
基金supported by the National Natural Science Foundation of China,No.31970968(to SYL)the Collegiate Natural Science Foundation of Jiangsu Province,No.16KJA310005(to SYL)+1 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions[PAPD]the Natural Science Foundation of Jiangsu Province,No.BK20200976(to XHW).
文摘Neurotrophic factors,particularly nerve growth factor,enhance neuronal regeneration.However,the in vivo applications of nerve growth factor are largely limited by its intrinsic disadvantages,such as its short biological half-life,its contribution to pain response,and its inability to cross the blood-brain barrier.Considering that let-7(human miRNA)targets and regulates nerve growth factor,and that let-7 is a core regulator in peripheral nerve regeneration,we evaluated the possibilities of let-7 application in nerve repair.In this study,anti-let-7a was identified as the most suitable let-7 family molecule by analyses of endogenous expression and regulatory relationship,and functional screening.Let-7a antagomir demonstrated biosafety based on the results of in vivo safety assessments and it entered into the main cell types of the sciatic nerve,including Schwann cells,fibroblasts and macrophages.Use of hydrogel effectively achieved controlled,localized,and sustained delivery of let-7a antagomir.Finally,let-7a antagomir was integrated into chitosan conduit to construct a chitosan-hydrogel scaffold tissue-engineered nerve graft,which promoted nerve regeneration and functional recovery in a rat model of sciatic nerve transection.Our study provides an experimental basis for potential in vivo application of let-7a.
基金The authors sincerely appreciate the financial support from the National Natural Science Foundation of China(No.52074249,51874261)Fundamental Research Funds for the Central Universities(2-9-2019-103).
文摘Due to the low porosity and low permeability in unconventional reservoirs,a large amount of crude oil is trapped in micro-to nano-sized pores and throats,which leads to low oil recovery.Nanofluids have great potential to enhance oil recovery(EOR)in low permeability reservoirs.In this work,the regulating ability of a nanofluid at the oil/water/solid three-phase interface was explored.The results indicated that the nanofluid reduced the oil/water interfacial tension by two orders of magnitude,and the expansion modulus of oil/water interface was increased by 77% at equilibrium.In addition,the solid surface roughness was reduced by 50%,and the three-phase contact angle dropped from 135(oil-wet)to 48(water-wet).Combining the displacement experiments using a 2.5D reservoir micromodel and a microchannel model,the remaining oil mobilization and migration processes in micro-to nano-scale pores and throats were visualized.It was found that the nanofluid dispersed the remaining oil into small oil droplets and displaced them via multiple mechanisms in porous media.Moreover,the high strength interface film formed by the nanofluid inhibited the coalescence of oil droplets and improved the flowing ability.These results help to understand the EOR mechanisms of nanofluids in low permeability reservoirs from a visual perspective.
文摘A rate-dependent constitutive model for saturated frozen soil is vital in frozen soil mechanics,especially when simultaneously describing the nonlinearity,dilatancy and strain-softening characteristics.The distribution of the non-uniform strain rate of saturated frozen soil at the meso-scale due to the local icecementation breakage is described by a newly binary-medium-based homogenization equation.Based on the field-equation-based approach of the meso-mechanics theory,the interaction expression of the strain rate at macro-and meso-scale is derived,which can give the strain rate concentration tensor at different crushed degrees.With the thermodynamics and empirical assumption,a breakage ratio in the rate-dependent form is determined.This overcomes the limitations of the existing binary-medium-based models that are difficult to simulate rate-dependent mechanical response.Based on these assumptions,a newly binary-medium-based rate-dependent model is proposed considering both the ice bond breakage and material composition characteristics of saturated frozen soil.The proposed constitutive model has been validated by the test results on frozen soils with different temperatures and strain rates.
基金financially supported by the National Natural Science Foundation of China (22078132 and 22108103)Open Funding Project of the National Key Laboratory of Biochemical Engineering (2021KF-02)+3 种基金China Postdoctoral Science Foundation (2021M691301)Jiangsu Agricultural Independent Innovation Fund Project (CX(21)3079)Graduate Research Innovation Program of Jiangsu Province (KYCX20-3040)China Postdoctoral Science Foundation (2021M691301)。
文摘Molecularly imprinted polymers (MIPs) have great potential as adsorbents for selective adsorption and separation of nucleoside compounds,but effectively enhancing the affinity of recognition sites by adjusting the forces between template molecules and functional monomers remains an important challenge.In this work,a surface imprinting strategy was used to construct bowl-shaped molecularly imprinted composite sorbents (BHPN@MIPs) based on polydopamine (PDA) particles and have achieved selective separation and purification of 2'-deoxyadenosine (dA).Where by the base complementary pairing interaction of the combined template molecule d A and the pyrimidine functional monomer can enhance the preassembly force,and the hydrophilic bowl-shaped PDA can provide a larger storage space contact efficiency of d A in the test solution,causing the site utilization much higher and improving the kinetic adsorption performance.The equilibrium adsorption time and maximum adsorption capacity of60 min and 328.45μmol·g^(-1)were observed by static adsorption experiments,and the selectivity experimental results showed an imprinting factor IF of 1.30.After four adsorption–desorption cycles,the initial adsorption equilibrium adsorption capacity of BHPN@MIPs still retained 91.14%.By evaluating the selective adsorption of d A in spiked human serum solutions,BHPN@MIPs can be used to selectively enrich and analyze target d A in complex biological samples.
基金Project supported by the National Natural Science Foundation of China (Grant No.92050116)。
文摘Optical vortices with tunable polarization states and topological charges are widely investigated in various physical systems and practical devices for high-capacity optical communication.However,this kind of structured light beams is usually generated using several polarization and spatial phase devices,which decreases the configurability of optical systems.Here,we have designed a kind of polarized optical multi-vortices generator based on the Stokes-Mueller formalism and cross-phase modulation.In our scheme,multi-channel generation of polarized vortex beams can be realized through a single optical element and a single-input Gaussian beam.The polarization states and orbital angular momentum of the generated light beams are all-optically controllable.Furthermore,the proposed polarized optical multi-vortices generator has also been demonstrated experimentally through one-step holographic recording in an azobenzene liquid-crystalline film and the experimental results agree with theoretical analysis.
基金supported by in part by the National Natural Science Fund (81900382)supported,in part,by the Yang Talents Program of Beijing (QML20200302)Beijing Municipal Natural Science Foundation (7222072)
文摘BACKGROUND Growth differentiation factor 15(GDF-15)has been explored as a potential biomarker for various inflammatory diseases and cardiovascular events.This study aimed to assess the predictive role of GDF-15 levels in cardiovascular events and all-cause mortality,considering traditional risk factors and other biomarkers.METHODS A prospective study was conducted and 3699 patients with stable coronary artery disease(CAD)were enrolled into the research.Baseline GDF-15 levels were measured.Median follow-up was 3.1 years during the study.We analyzed clinical variables and several biomarkers.Multivariable Cox regression analysis was performed to evaluate prognostic performance of GDF-15 levels in predicting myocardial infarction(MI),heart failure,stroke,cardiovascular death,and non-cardiovascular death.RESULTS Baseline GDF-15 levels for 3699 patients were grouped by quartile(≤1153,1153-1888,1888-3043,>3043 ng/L).Higher GDF-15 levels were associated with older age,male gender,history of hypertension,and elevated levels of N-terminal pro Btype natriuretic peptide(NT-pro BNP),soluble suppression of tumorigenesis-2(sST2),and creatine(each with P<0.001).Adjusting for established risk factors and biomarkers in Cox proportional hazards models,a 1 standard deviation(SD)increase in GDF-15 was associated with elevated risk of clinical events[hazard ratio(HR)=2.18,95%confidence interval(CI):(1.52-3.11)],including:MI[HR=2.8395%CI:(1.03-7.74)],heart failure[HR=2.7195%CI:(1.18-6.23)],cardiovascular and non-cardiovascular death[HR=2.48,95%CI(1.49-4.11)]during the median follow up of 3.1 years.CONCLUSIONS Higher levels of GDF-15 consistently provides prognostic information for cardiovascular events and all cause death,independent of clinical risk factors and other biomarkers.GDF-15 could be considered as a valuable addition to future risk prediction model in secondary prevention for predicting clinical events in patient with stable CAD.
基金Supported by Zunyi Medical College Research Start Fund,No.2017CK-1130-038。
文摘BACKGROUND Benign lymphoepithelial cyst(BLEC)of the parotid gland is a rare benign embryonic-dysplastic cystic tumor in the anterolateral neck that occurs most commonly in human immunodeficiency virus(HIV)-positive adults and rarely in non-acquired immune deficiency syndrome patients.The main presentation is a slow-growing,painless mass,and secondary infection may cause acute inflammatory symptoms.CASE SUMMARY A 44-year-old Chinese male patient presented with a 1-year history of a mass in the left side of the neck.On physical examination,a mass similar in size and shape to a quail egg was found in the left parotid gland.The mass was tough,without tenderness,and easily moveable.The results of HIV tests,including antibody and nucleic acid tests and CD4+T cell examination,were negative.Imaging examination revealed a left parotid gland mass.The patient underwent surgical treatment,and BLEC was diagnosed based on postoperative pathology.After 2years of follow-up,the patient survived well without related discomfort.CONCLUSION The detailed characteristics of a BLEC in a patient without HIV infection contribute to an improved understanding of this rare disease.
基金support of the National Natural Science Foundation of China(Grant Nos.62075030,62075201,and 11904339)the Sichuan Provincial Project for Outstanding Young Scholars in Science and Technology(Grant No.2020JDJQ0024)。
文摘Broadband low-coherence light is considered to be an effective way to suppress laser plasma instability.Recent studies have demonstrated the ability of low-coherence laser facilities to reduce back-scattering during beam–target coupling.However,to ensure simultaneous low coherence and high energy,complex spectral modulation methods and amplification routes have to be adopted.In this work,we propose the use of a random fiber laser(RFL)as the seed source.The spectral features of this RFL can be carefully tailored to provide a good match with the gain characteristics of the laser amplification medium,thus enabling efficient amplification while maintaining low coherence.First,a theoretical model is constructed to give a comprehensive description of the output characteristics of the spectrum-tailored RFL,after which the designed RFL is experimentally realized as a seed source.Through precise pulse shaping and efficient regenerative amplification,a shaped random laser pulse output of 28 mJ is obtained,which is the first random laser system with megawatt-class peak power that is able to achieve low coherence and efficient spectrum-conformal regenerative amplification.
文摘BACKGROUND Gastric cancer(GC)is one of the most common malignant tumors with poor prognosis in terms of advanced stage.However,the survival-associated biomarkers for GC remains unclear.AIM To investigate the potential biomarkers of the prognosis of patients with GC,so as to provide new methods and strategies for the treatment of GC.METHODS RNA sequencing data from The Cancer Genome Atlas(TCGA)database of STAD tumors,and microarray data from Gene Expression Omnibus(GEO)database(GSE19826,GSE79973 and GSE29998)were obtained.The differentially expressed genes(DEGs)between GC patients and health people were picked out using R software(x644.1.3).The intersections were underwent between the above obtained co-expression of differential genes(co-DEGs)and the DEGs of GC from Gene Expression Profiling Interactive Analysis database,and Gene Ontology(GO)analysis,Kyoto Encyclopedia of Gene and Genome(KEGG)pathway analysis,Gene Set Enrichment Analysis(GSEA),Protein-protein Interaction(PPI)analysis and Kaplan-Meier Plotter survival analysis were performed on these DEGs.Using Immunohistochemistry(IHC)database of Human Protein Atlas(HPA),we verified the candidate Hub genes.RESULTS With DEGs analysis,there were 334 co-DEGs,including 133 up-regulated genes and 201 down-regulated genes.GO enrichment analysis showed that the co-DEGs were involved in biological process,cell composition and molecular function pathways.KEGG enrichment analysis suggested the co-DEGs pathways were mainly enriched in ECM-receptor interaction,protein digestion and absorption pathways,etc.GSEA pathway analysis showed that co-DEGs mainly concentrated in cell cycle progression,mitotic cell cycle and cell cycle pathways,etc.PPI analysis showed 84 nodes and 654 edges for the co-DEGs.The survival analysis illustrated 11 Hub genes with notable significance for prognosis of patients were screened.Furtherly,using IHC database of HPA,we confirmed the above candidate Hub genes,and 10 Hub genes that associated with prognosis of GC were identified,namely BGN,CEP55,COL1A2,COL4A1,FZD2,MAOA,PDGFRB,SPARC,TIMP1 and VCAN.CONCLUSION The 10 Hub genes may be the potential biomarkers for predicting the prognosis of GC,which can provide new strategies and methods for the diagnosis and treatment of GC.
文摘目的探讨生物反馈电刺激联合心理干预对产后女性性功能障碍(FSD)的治疗效果。方法选取2014年1月-2016年12月河北医科大学第一医院盆底康复中心收治的产后42 d FSD患者400例作为研究对象,根据随机信封抽签原则分为观察组与对照组各200例,对照组给予一般产后健康教育,观察组给予生物反馈电刺激联合心理干预,持续观察3个月。结果观察组治疗后盆底肌力改善率优于对照组(P<0.05)。观察组与对照组治疗后的膀胱初感充盈量与最大充盈量均高于治疗前(P<0.05),同时治疗后观察组的膀胱初感充盈量与最大充盈量高于对照组(P<0.05)。治疗后发现观察组患者的焦虑与抑郁评分比对照组患者低(P<0.05),同时治疗后观察组的焦虑和抑郁评分也低于对照组(P<0.05)。治疗后观察组的1个月性生活次数与性高潮频率都高于对照组(P<0.05),且观察组的性交痛发生率低于对照组(P<0.05)。结论生物反馈电刺激联合心理干预治疗FSD能有效改善膀胱的生物学功能,提高盆底肌力,有效缓解患者的焦虑与抑郁程度,从而提高性生活质量。
