Liver transplantation(LT)has made significant progress in the treatment of end stage liver disease(ESLD).However,many patients still die from disease progression while awaiting transplantation.As the number of patient...Liver transplantation(LT)has made significant progress in the treatment of end stage liver disease(ESLD).However,many patients still die from disease progression while awaiting transplantation.As the number of patients on LT waiting lists is increasing,and the organ shortage crisis is obvious,various efforts have been made to increase the pool of available liver grafts[1].In addition to living donor liver transplantation(LDLT),improving the utilization rate of extended criteria donor(ECD)livers is an important way.However,under traditional cold storage,ECD livers are usually associated with a higher risk of ischemic biliary disease,early allograft dysfunction(EAD)or even primary nonfunction(PNF).The frequently described definition in the literature for ECD grafts generally includes elderly,steatotic,long cold ischemia time(CIT),grafts obtained from donation after circulatory death(DCD),split liver grafts,donors with increased risk of infectious disease transmission and prolonged donor intensive care unit stay[2].展开更多
Bolting steel angles at the bottom ends of columns provides a rapid and efficient method for repairing damaged structures,while also offering a viable approach to restore their potential bearing capacity.To validate t...Bolting steel angles at the bottom ends of columns provides a rapid and efficient method for repairing damaged structures,while also offering a viable approach to restore their potential bearing capacity.To validate the suitability of specific strengthening strategies,particularly the utilization of bolted steel angles,three reinforced concrete frame specimens were subjected to hysteresis testing.These specimens all featured RC columns strengthened with steel angle ends.Additionally,one control specimen without steel angle ends was included in the testing.The hysteresis effects of bolting steel angles were discussed in terms of typical failure mode,hysteresis and skeleton curves,stiffness degradation and energy dissipation.The experimental results revealed that the three specimens that had bolted steel angles exhibited ductile failure behavior.Through analysis of hysteresis and skeleton curves,it was observed that the frame demonstrated distinct plasticity,maintaining sufficient load-bearing capacity even after yielding and exhibiting superior displacement ductility performance.Considering equivalent viscous damping,the energy dissipation capacity of the RC frame increased linearly with drift and remained largely unaffected by structural damage.Therefore,bolting steel angles at specified cross-sections proved to be a viable technique for structural repair and restoration.展开更多
In the current state-of-the-art,high-loss flow in the endwall significantly influences compressor performance.Therefore,the control of endwall corner separation in compressor blade rows is important to consider.Based ...In the current state-of-the-art,high-loss flow in the endwall significantly influences compressor performance.Therefore,the control of endwall corner separation in compressor blade rows is important to consider.Based on the previous research of the Blended Blade and End Wall(BBEW)technique,which can significantly reduce corner separation,in combination with a nonaxisymmetric endwall,the full-BBEW technique is proposed in this study to further reduce the separation in endwall region.The principle of the unchanged axial passage area is considered to derive the geometric method for this technique.Three models are further classified based on different geometric characteristics of this technique:the BBEW model,Inclining-Only End Wall(IOEW)model,and full-BBEW model.The most effective design of each model is then found by performing several optimizations at the design point and related numerical investigations over the entire operational conditions.Compared with the prototype,the total pressure loss coefficient decreases by 7%–9%in the optimized full-BBEW at the design point.Moreover,the aerodynamic blockage coefficient over the entire operational range decreases more than the other models,which shows its positive effect for diffusion.This approach has a larger decrease at negative incidence angles where the intersection of the boundary layer plays an important role in corner separation.The analysis shows that the blended blade profile enlarges the dihedral angle and creates a span-wise pressure gradient to move low momentum fluid towards the mainstream.Furthermore,the inclining hub geometry accelerates the accumulated flow in the corner downstream by increasing the pressure gradient.Overall,though losses in the mainstream grow,especially for large incidences,the full-BBEW technique effectively reduces the separation in corners.展开更多
In this paper,a stand-alone photovoltaic(PV)system based on a Double Ended Forward Converter(DEFC)is presented.The proposed converter is specified for 48 V,100Wapplications as most of the equipment used in telecommuni...In this paper,a stand-alone photovoltaic(PV)system based on a Double Ended Forward Converter(DEFC)is presented.The proposed converter is specified for 48 V,100Wapplications as most of the equipment used in telecommunication and aircraft fall in this range.The literature has limited potential application of DEFCin PV systems.The research work deals with an in-depth study of DEFCand proposes an improvedDEFCfor PV applications with battery backup.Besides,a bi-directional dc-dc converter for the battery is integrated to track theMaximumPower Point(MPP)of the PV generator.The converter is examined under variable irradiance and load conditions,and the analytical analysis of boundary conditions are implemented.The converter’s architecture also ensures built-in I-V curve tracing for the identification of MPP of PV generator.It offers low voltage stresses across switches and avoids sinking power supply and core resetting circuits.The topology’s behavior is analyzed based onMPP achievement and maintaining output under different conditions of battery backup availability,environmental,and load conditions.The PV system architecture is designed and analyzed theoretically and verified with simulations on the PSIM software.展开更多
Traditionally,semi-rigid analysis of extended end plate connections is assumed to be deterministic parameters.Most of the moment-rotation models of the joint are determined by curve-fitting and statistically regressed...Traditionally,semi-rigid analysis of extended end plate connections is assumed to be deterministic parameters.Most of the moment-rotation models of the joint are determined by curve-fitting and statistically regressed with the test data.Parameters of these models have little physical meaning,and the effect of correlations in the parameters is neglected.This paper deals with a semi-rigid joint of extended end plate connections based on correlation and sensitivity analysis.A numerical study was carried out and the finite element analysis was validated compared with the experimental results.The relative moment-rotation model was concluded based on correlations in parameters and probabilistic sentivity analysis.The relationship between height and width of steel beam was partial correlation.The relationship between thickness of steel beam flange and thickness of steel beam web was also partial correlation.Height and width of steel beam,and distance of upper bolts to axle wire of steel beam section were important sensitive parameters for the extended end plate connections.展开更多
The electron transport properties of various molecular junctions based on the thiol-ended oligosilane are investigated through density functional theory combined with non-equilibrium Green＇s function formalism. Our c...The electron transport properties of various molecular junctions based on the thiol-ended oligosilane are investigated through density functional theory combined with non-equilibrium Green＇s function formalism. Our calculations show that oligosilanes doped by the phenyl and -C10H6 groups demonstrate better rectifying effect and their rectification ratios are up to 15.41 and 65.13 for their molecular junctions. The current-voltage （I-V） curves of all the Au/ modified oligosilane/Au systems in this work are illustrated by frontier molecular orbitals, transmission spectra and density of states under zero bias. And their rectifying behaviors are analyzed through transmission spectra.展开更多
Multiscale simulations of the tilted flat-ended nanoindentation with different tilted angles （from 5° ～ 30°） on the （-1 1 0） surface of nickel crystal were studied using the QC method. The model of the ...Multiscale simulations of the tilted flat-ended nanoindentation with different tilted angles （from 5° ～ 30°） on the （-1 1 0） surface of nickel crystal were studied using the QC method. The model of the indentation is a flat-end indenter inclined by an angle ε driven into a half- plane vertically. Load-displacement responses, initiM stages of the plasticity deformations and dislocation emissions for nickel film at different inclined angles were obtained and analyzed as well. An energy criterion was successfully proposed to analyze the critical load for the first dislocation emission beneath the edge of the indenter. Simulation results agree well with analytical ones. An elastic model based on the contact theory and the Peierls-Nabarro dislocation model were combined to analyze when and where the dislocation will be emitted beneath the lower surface of an inclined indenter. Results indicate that the key parameter is the ratio of the contact half- width to the position of the slip plane. This parameter shows the range in which a dislocation will probably be emitted. This mechanism explains the simulation results well. This work is of value for understanding the mechanism of dislocation emissions of FCC crystals under tilted flat- ended nanoindentation while providing approaches to predicting when the first dislocation will be emitted and where subsequent dislocations will probably be emitted.展开更多
The counter-intuitive behaviors of pin-ended beams under the projectile impact axe investigated with ANSYS/LS-DYNA in this paper. It studies in detail their displacement-time history curves, final deformed shapes, ene...The counter-intuitive behaviors of pin-ended beams under the projectile impact axe investigated with ANSYS/LS-DYNA in this paper. It studies in detail their displacement-time history curves, final deformed shapes, energy relationships and projectile impact velocity ranges related to their counter-intuitive behaviors. The influences of the impact positions on their counterintuitive behaviors are also discussed. The results show that no matter where the impact position on the beam is, the counter-intuitive behaviors of pinned beams will occur as long as the impacting velocity lies within a proper range. Corresponding to the occurring of the counter-intuitive behaviors, the rebounding number in the displacement history curves of the beams decreases from a few times to zero with an increase of the impact velocity. The final deformation modes of the beam corresponding to the counter-intuitive behaviors will appear in symmetrical and unsymmetrical forms no matter where the impact position is; the impact velocity of the first-occurring of the counter-intuitive behaviors of the beam increases slowly with the deviation of the impact position away from the mid-span.展开更多
Three countries and areas take a leading role in the transaction.The top three are the European Union(EU),the Middle East and the USA,the transaction amounts were respectively US$2.32 billion,US$931 billion and US$927...Three countries and areas take a leading role in the transaction.The top three are the European Union(EU),the Middle East and the USA,the transaction amounts were respectively US$2.32 billion,US$931 billion and US$927 million.展开更多
OBJECTIVE:To evaluate the therapeutic effects of Xiahuo Pingwei San(夏藿平胃散,XHPWS)on ulcerative colitis(UC)in mice and to explore the underlying mechanisms through a network pharmacology approach.METHODS:Ultra-perf...OBJECTIVE:To evaluate the therapeutic effects of Xiahuo Pingwei San(夏藿平胃散,XHPWS)on ulcerative colitis(UC)in mice and to explore the underlying mechanisms through a network pharmacology approach.METHODS:Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF/MS)was utilized to identify the chemical composition and authenticate the active constituents of XHPWS,ensuring rigorous quality control across batches.A dextran sulfate sodium(DSS)-induced UC model was established in C57BL/6 mice,which were treated with XHPWS in vivo.The efficacy against UC was assessed by measuring parameters such as body weight,disease activity index(DAI)scores,and colon length.Levels of inflammatory cytokines,including interleukin-6(IL-6),interleukin-1β(IL-1β),and tumor necrosis factor-alpha(TNF-α),in colonic tissue were evaluated using enzymelinked immunosorbent assay(ELISA).Histological analysis of colon sections was conducted using hematoxylin and eosin staining.A network pharmacology approach was employed to explore the mechanisms of XHPWS and to predict its potential targets in UC treatment.Predicted protein expressions in colonic tissue were validated using immune-ohistochemistry(IHC)and Western blotting techniques.RESULTS:XHPWS effectively alle via ted DSS-induced UC symptoms in mice,as evidenced by restored body weight,reduced colon shortening,and decreased DAI scores.Histopathological examination revealed that XHPWS significantly reduced intestinal inflammatory infiltration,restored intestinal epithelial permeability,and increased goblet cell count.Network pharmacology analysis identified 63 active compounds in XHPWS and suggested that it might target 35 potential proteins associated with UC treatment.Functional enrichment analysis indicated that the protective mechanism of XHPWS could be related to the advanced glycation end products-receptor for advanced glycation end products(AGE-RAGE)signaling pathway.Notably,quercetin,kaempferol,wogonin,and nobiletin,the main components of XHPWS,showed strong correlations with the core targets.Additionally,experimental validation demonstrated that XHPWS significantly decreased levels of inflammatory cytokines interleukin 6(IL-6),interleukin 1 beta(IL-1β),and tumor necrosis factor alpha(TNF-α)in UC mice,while downregulating the expression of proteins related to the AGE-RAGE pathway.CONCLUSION:Our study demonstrated that XHPWS effectively alle via tes colitis symptoms and inflammation in UC mice,potentially through the regulation of the AGE-RAGE pathway.These findings provide strong evidence for the therapeutic potential of XHPWS in UC treatment,thereby broadening its clinical applications.展开更多
The dynamic load characteristics of a proton exchange membrane fuel cell（PEMFC） with a dead-ended anode were studied. In a 70 h experiment, the effects of anode pressure, operating temperature, and relative humidity...The dynamic load characteristics of a proton exchange membrane fuel cell（PEMFC） with a dead-ended anode were studied. In a 70 h experiment, the effects of anode pressure, operating temperature, and relative humidity of the cathode on the performances of the fuel cell were investigated. The obtained results show that, with different relative humidity of the cathode at 65 ℃, dynamic loading has little effect on the performances of fuel cell and the electrochemically active surface area（ECSA）. However, the fuel cell operating under dynamic load is unstable when the relative humidity is 50%, and at 50 ℃ with 100% relative humidity, applying a dynamic load has a significant influence on the fuel cell performances. Scanning electron microscopy（SEM） showed that both the upstream and middle catalyst layers of the cell were unchanged, whereas the downstream cathode catalyst layer thinned as a response to dynamic load.展开更多
CHINA＇S stock market plunge and a depreciation of the yuan caused by the country＇s foreign exchange reform triggered turmoil in global markets in August. Some even claim that the yuan exchange rate will collapse, ca...CHINA＇S stock market plunge and a depreciation of the yuan caused by the country＇s foreign exchange reform triggered turmoil in global markets in August. Some even claim that the yuan exchange rate will collapse, causing capital outflow to spiral out of control. Market fears about China＇s fall are more prominent than they have been in a decade.展开更多
Saccular extended obstruction is generated when the anastomotic site of functional end-to-end anastomosis is extended saccularly and blocked by intestinal contents. This is a specific complication of functional end-to...Saccular extended obstruction is generated when the anastomotic site of functional end-to-end anastomosis is extended saccularly and blocked by intestinal contents. This is a specific complication of functional end-to-end anastomosis. Saccular extended obstruction of the anastomotic site of func-tional end-to-end anastomosis causes postoperative intestinal obstruction. Saccular extended obstruction places a heavy burden on patients because surgery is necessary for treatment of intestinal obstruction due to saccular extended obstruction. However, saccular extended obstruction is not a commonly recognized complication. The greatest factor contributing to the development of saccular extended obstruction is an acute angle between the portions of the intestinal tract oral and aboral to the anastomotic site. When this angle approaches obtuse angle, preferably close to a straight line, stagnation of the intestinal contents does not occur at the anastomotic site of functional end-to-end anastomosis and saccular extended obstruction is avoided. For making the angle of anastomotic intestinal tracts obtuse or straight, it may be effective that the entry hole of stapling suture instrument creating the anastomotic stoma is closed perpendicular to the intestinal axis.展开更多
The 15th China’s International Chemical Fiber Conference was held at Hangzhou, Zhejiang Province on June 10th-12th, 2009. The theme of the conference is "Financial Crisis and Chemical Fiber Industry". Hundr...The 15th China’s International Chemical Fiber Conference was held at Hangzhou, Zhejiang Province on June 10th-12th, 2009. The theme of the conference is "Financial Crisis and Chemical Fiber Industry". Hundreds of delegates展开更多
Acceptor-donor-acceptor(A-D-A)type molecules,of which the novel non-fused azacyclic end-group pyrazoli-nones were modified with chlorine substitution on the phenyl ring,were synthesized.The non-fused azacyclic end-gro...Acceptor-donor-acceptor(A-D-A)type molecules,of which the novel non-fused azacyclic end-group pyrazoli-nones were modified with chlorine substitution on the phenyl ring,were synthesized.The non-fused azacyclic end-group py-razolinones have the advantages of simple synthesis steps,low cost and environmental friendliness,compared to the classical end-group dicyanomethyleneindianone.The properties of the synthesized A-D-A type molecules with non-fused azacyclic end groups were characterized by theoretical calculation,UV-vis absorption,cyclic voltammetry,X-ray diffraction and space charge limited current.It is shown that the strong UV-vis absorptions of the synthesized A-D-A type molecules are located in the wavelength range of 500~700 nm,with a moderate band gap of nearly 1.7 eV.At the same time,the influence of end-group chlorination on the properties of A-D-A type molecules was compared and explored.It is proven that this kind of A-D-A type molecule with non-fused azacyclic end groups has the potential to be applied as interfacial modified layer of the active layer in perovskite solar cell devices.展开更多
BACKGROUND Ampullary adenocarcinoma is a rare malignant tumor of the gastrointestinal tract.Currently,only a few cases have been reported,resulting in limited information on survival.AIM To develop a dynamic nomogram ...BACKGROUND Ampullary adenocarcinoma is a rare malignant tumor of the gastrointestinal tract.Currently,only a few cases have been reported,resulting in limited information on survival.AIM To develop a dynamic nomogram using internal and external validation to predict survival in patients with ampullary adenocarcinoma.METHODS Data were sourced from the surveillance,epidemiology,and end results stat database.The patients in the database were randomized in a 7:3 ratio into training and validation groups.Using Cox regression univariate and multivariate analyses in the training group,we identified independent risk factors for overall survival and cancer-specific survival to develop the nomogram.The nomogram was validated with a cohort of patients from the First Affiliated Hospital of the Army Medical University.RESULTS For overall and cancer-specific survival,12(sex,age,race,lymph node ratio,tumor size,chemotherapy,surgical modality,T stage,tumor differentiation,brain metastasis,lung metastasis,and extension)and 6(age;surveillance,epidemiology,and end results stage;lymph node ratio;chemotherapy;surgical modality;and tumor differentiation)independent risk factors,respectively,were incorporated into the nomogram.The area under the curve values at 1,3,and 5 years,respectively,were 0.807,0.842,and 0.826 for overall survival and 0.816,0.835,and 0.841 for cancer-specific survival.The internal and external validation cohorts indicated good consistency of the nomogram.CONCLUSION The dynamic nomogram offers robust predictive efficacy for the overall and cancer-specific survival of ampullary adenocarcinoma.展开更多
Let T be a tree. The set of leaves of Τ is denoted by Leaf(Τ). The subtree Τ—Leaf(Τ) of T is called the stem of Τ. A stem is called a k-ended stem if it has at most k-leaves in it. In this paper, we prove the fo...Let T be a tree. The set of leaves of Τ is denoted by Leaf(Τ). The subtree Τ—Leaf(Τ) of T is called the stem of Τ. A stem is called a k-ended stem if it has at most k-leaves in it. In this paper, we prove the following theorem. Let G be a connected graph and k≥2 be an integer. Let u and ν be a pair of nonadjacent vertices in G. Suppose that |NG(u)∪NG(v)|≥|G|-k-1. Then G has a spanning tree with k-ended stem if and only if G+uv has a spanning tree with k-ended stem. Moreover, the condition on |NG(u)∪NG(v)| is sharp.展开更多
文摘Liver transplantation(LT)has made significant progress in the treatment of end stage liver disease(ESLD).However,many patients still die from disease progression while awaiting transplantation.As the number of patients on LT waiting lists is increasing,and the organ shortage crisis is obvious,various efforts have been made to increase the pool of available liver grafts[1].In addition to living donor liver transplantation(LDLT),improving the utilization rate of extended criteria donor(ECD)livers is an important way.However,under traditional cold storage,ECD livers are usually associated with a higher risk of ischemic biliary disease,early allograft dysfunction(EAD)or even primary nonfunction(PNF).The frequently described definition in the literature for ECD grafts generally includes elderly,steatotic,long cold ischemia time(CIT),grafts obtained from donation after circulatory death(DCD),split liver grafts,donors with increased risk of infectious disease transmission and prolonged donor intensive care unit stay[2].
基金National Key R&D Program of China under Grant No.2023YFC3805100Technologies R&D Project of China Construction First Group Corporation Limited under Grant No.PT-2022-09National Natural Science Foundation of China under Grant No.52178126。
文摘Bolting steel angles at the bottom ends of columns provides a rapid and efficient method for repairing damaged structures,while also offering a viable approach to restore their potential bearing capacity.To validate the suitability of specific strengthening strategies,particularly the utilization of bolted steel angles,three reinforced concrete frame specimens were subjected to hysteresis testing.These specimens all featured RC columns strengthened with steel angle ends.Additionally,one control specimen without steel angle ends was included in the testing.The hysteresis effects of bolting steel angles were discussed in terms of typical failure mode,hysteresis and skeleton curves,stiffness degradation and energy dissipation.The experimental results revealed that the three specimens that had bolted steel angles exhibited ductile failure behavior.Through analysis of hysteresis and skeleton curves,it was observed that the frame demonstrated distinct plasticity,maintaining sufficient load-bearing capacity even after yielding and exhibiting superior displacement ductility performance.Considering equivalent viscous damping,the energy dissipation capacity of the RC frame increased linearly with drift and remained largely unaffected by structural damage.Therefore,bolting steel angles at specified cross-sections proved to be a viable technique for structural repair and restoration.
基金sponsored by the National Natural Science Foundation of China(Nos.51676015 and 51976010)National Major Science and Technology Project of China(Nos.2017-II0006-0020 and 2017-II-0001-0013)Beijing Institute of Technology Research Fund Program for Young Scholars,China。
文摘In the current state-of-the-art,high-loss flow in the endwall significantly influences compressor performance.Therefore,the control of endwall corner separation in compressor blade rows is important to consider.Based on the previous research of the Blended Blade and End Wall(BBEW)technique,which can significantly reduce corner separation,in combination with a nonaxisymmetric endwall,the full-BBEW technique is proposed in this study to further reduce the separation in endwall region.The principle of the unchanged axial passage area is considered to derive the geometric method for this technique.Three models are further classified based on different geometric characteristics of this technique:the BBEW model,Inclining-Only End Wall(IOEW)model,and full-BBEW model.The most effective design of each model is then found by performing several optimizations at the design point and related numerical investigations over the entire operational conditions.Compared with the prototype,the total pressure loss coefficient decreases by 7%–9%in the optimized full-BBEW at the design point.Moreover,the aerodynamic blockage coefficient over the entire operational range decreases more than the other models,which shows its positive effect for diffusion.This approach has a larger decrease at negative incidence angles where the intersection of the boundary layer plays an important role in corner separation.The analysis shows that the blended blade profile enlarges the dihedral angle and creates a span-wise pressure gradient to move low momentum fluid towards the mainstream.Furthermore,the inclining hub geometry accelerates the accumulated flow in the corner downstream by increasing the pressure gradient.Overall,though losses in the mainstream grow,especially for large incidences,the full-BBEW technique effectively reduces the separation in corners.
文摘In this paper,a stand-alone photovoltaic(PV)system based on a Double Ended Forward Converter(DEFC)is presented.The proposed converter is specified for 48 V,100Wapplications as most of the equipment used in telecommunication and aircraft fall in this range.The literature has limited potential application of DEFCin PV systems.The research work deals with an in-depth study of DEFCand proposes an improvedDEFCfor PV applications with battery backup.Besides,a bi-directional dc-dc converter for the battery is integrated to track theMaximumPower Point(MPP)of the PV generator.The converter is examined under variable irradiance and load conditions,and the analytical analysis of boundary conditions are implemented.The converter’s architecture also ensures built-in I-V curve tracing for the identification of MPP of PV generator.It offers low voltage stresses across switches and avoids sinking power supply and core resetting circuits.The topology’s behavior is analyzed based onMPP achievement and maintaining output under different conditions of battery backup availability,environmental,and load conditions.The PV system architecture is designed and analyzed theoretically and verified with simulations on the PSIM software.
基金the National Natural Science Foundation of China(Nos.50978104,51008129 and 51178192)the China Postdoctoral Science Foundation (No.20110490895)+1 种基金the "Code for Design of Steel Structures" National Institute of Standards Management Group(No.GB500172010-04)the Fundamental Research Funds for the Central Universities of China (No.2012ZZ0099)
文摘Traditionally,semi-rigid analysis of extended end plate connections is assumed to be deterministic parameters.Most of the moment-rotation models of the joint are determined by curve-fitting and statistically regressed with the test data.Parameters of these models have little physical meaning,and the effect of correlations in the parameters is neglected.This paper deals with a semi-rigid joint of extended end plate connections based on correlation and sensitivity analysis.A numerical study was carried out and the finite element analysis was validated compared with the experimental results.The relative moment-rotation model was concluded based on correlations in parameters and probabilistic sentivity analysis.The relationship between height and width of steel beam was partial correlation.The relationship between thickness of steel beam flange and thickness of steel beam web was also partial correlation.Height and width of steel beam,and distance of upper bolts to axle wire of steel beam section were important sensitive parameters for the extended end plate connections.
基金supported by National Natural Science Foundation of China(21401023 and 21203027)Cultivating Fund for Excellent Young Scholar of Fujian Normal University(FJSDJK2012063)Program for Innovative Research Team in Science and Technology in Fujian Province University(IRTSTFJ)
文摘The electron transport properties of various molecular junctions based on the thiol-ended oligosilane are investigated through density functional theory combined with non-equilibrium Green＇s function formalism. Our calculations show that oligosilanes doped by the phenyl and -C10H6 groups demonstrate better rectifying effect and their rectification ratios are up to 15.41 and 65.13 for their molecular junctions. The current-voltage （I-V） curves of all the Au/ modified oligosilane/Au systems in this work are illustrated by frontier molecular orbitals, transmission spectra and density of states under zero bias. And their rectifying behaviors are analyzed through transmission spectra.
基金supported by the Science and Technology Innovation Talents Special Fund of Harbin(No.2012RFQXG001)the National Natural Science Foundation of China(No.11102053)the China Scholarship Council(CSC)
文摘Multiscale simulations of the tilted flat-ended nanoindentation with different tilted angles （from 5° ～ 30°） on the （-1 1 0） surface of nickel crystal were studied using the QC method. The model of the indentation is a flat-end indenter inclined by an angle ε driven into a half- plane vertically. Load-displacement responses, initiM stages of the plasticity deformations and dislocation emissions for nickel film at different inclined angles were obtained and analyzed as well. An energy criterion was successfully proposed to analyze the critical load for the first dislocation emission beneath the edge of the indenter. Simulation results agree well with analytical ones. An elastic model based on the contact theory and the Peierls-Nabarro dislocation model were combined to analyze when and where the dislocation will be emitted beneath the lower surface of an inclined indenter. Results indicate that the key parameter is the ratio of the contact half- width to the position of the slip plane. This parameter shows the range in which a dislocation will probably be emitted. This mechanism explains the simulation results well. This work is of value for understanding the mechanism of dislocation emissions of FCC crystals under tilted flat- ended nanoindentation while providing approaches to predicting when the first dislocation will be emitted and where subsequent dislocations will probably be emitted.
基金Project supported by Shanxi Province Returned Scholars Fund (No.200335).
文摘The counter-intuitive behaviors of pin-ended beams under the projectile impact axe investigated with ANSYS/LS-DYNA in this paper. It studies in detail their displacement-time history curves, final deformed shapes, energy relationships and projectile impact velocity ranges related to their counter-intuitive behaviors. The influences of the impact positions on their counterintuitive behaviors are also discussed. The results show that no matter where the impact position on the beam is, the counter-intuitive behaviors of pinned beams will occur as long as the impacting velocity lies within a proper range. Corresponding to the occurring of the counter-intuitive behaviors, the rebounding number in the displacement history curves of the beams decreases from a few times to zero with an increase of the impact velocity. The final deformation modes of the beam corresponding to the counter-intuitive behaviors will appear in symmetrical and unsymmetrical forms no matter where the impact position is; the impact velocity of the first-occurring of the counter-intuitive behaviors of the beam increases slowly with the deviation of the impact position away from the mid-span.
文摘Three countries and areas take a leading role in the transaction.The top three are the European Union(EU),the Middle East and the USA,the transaction amounts were respectively US$2.32 billion,US$931 billion and US$927 million.
基金the Guangdong Provincial Basic and Applied Basic Research Project:Mechanistic Study on the Regulation of Inflammatory Microenvironment and Improvement of Ulcerative Colitis by Lingnan Traditional Medicine Ficus Pandurata Hance through Wilms'Tumor 1-associating Protein-Mediated RNA Methyltransferase Promoting Toll Like Receptor 4 m6A Modification(2023A1515011699)the Zhongshan Medical Research Project:Mechanistic Study on the Action of Xiahuo Pingwei San in the Treatment of Ulcerative Colitis(2022A020446)。
文摘OBJECTIVE:To evaluate the therapeutic effects of Xiahuo Pingwei San(夏藿平胃散,XHPWS)on ulcerative colitis(UC)in mice and to explore the underlying mechanisms through a network pharmacology approach.METHODS:Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF/MS)was utilized to identify the chemical composition and authenticate the active constituents of XHPWS,ensuring rigorous quality control across batches.A dextran sulfate sodium(DSS)-induced UC model was established in C57BL/6 mice,which were treated with XHPWS in vivo.The efficacy against UC was assessed by measuring parameters such as body weight,disease activity index(DAI)scores,and colon length.Levels of inflammatory cytokines,including interleukin-6(IL-6),interleukin-1β(IL-1β),and tumor necrosis factor-alpha(TNF-α),in colonic tissue were evaluated using enzymelinked immunosorbent assay(ELISA).Histological analysis of colon sections was conducted using hematoxylin and eosin staining.A network pharmacology approach was employed to explore the mechanisms of XHPWS and to predict its potential targets in UC treatment.Predicted protein expressions in colonic tissue were validated using immune-ohistochemistry(IHC)and Western blotting techniques.RESULTS:XHPWS effectively alle via ted DSS-induced UC symptoms in mice,as evidenced by restored body weight,reduced colon shortening,and decreased DAI scores.Histopathological examination revealed that XHPWS significantly reduced intestinal inflammatory infiltration,restored intestinal epithelial permeability,and increased goblet cell count.Network pharmacology analysis identified 63 active compounds in XHPWS and suggested that it might target 35 potential proteins associated with UC treatment.Functional enrichment analysis indicated that the protective mechanism of XHPWS could be related to the advanced glycation end products-receptor for advanced glycation end products(AGE-RAGE)signaling pathway.Notably,quercetin,kaempferol,wogonin,and nobiletin,the main components of XHPWS,showed strong correlations with the core targets.Additionally,experimental validation demonstrated that XHPWS significantly decreased levels of inflammatory cytokines interleukin 6(IL-6),interleukin 1 beta(IL-1β),and tumor necrosis factor alpha(TNF-α)in UC mice,while downregulating the expression of proteins related to the AGE-RAGE pathway.CONCLUSION:Our study demonstrated that XHPWS effectively alle via tes colitis symptoms and inflammation in UC mice,potentially through the regulation of the AGE-RAGE pathway.These findings provide strong evidence for the therapeutic potential of XHPWS in UC treatment,thereby broadening its clinical applications.
基金Funded by the National Natural Science Foundation of China(Nos.51476119 and 51576147)the Natural Science Foundation of Hubei Province(No.2016CFA041)the Fundamental Research Funds for the Central Universities(No.2017 IVA 031)
文摘The dynamic load characteristics of a proton exchange membrane fuel cell（PEMFC） with a dead-ended anode were studied. In a 70 h experiment, the effects of anode pressure, operating temperature, and relative humidity of the cathode on the performances of the fuel cell were investigated. The obtained results show that, with different relative humidity of the cathode at 65 ℃, dynamic loading has little effect on the performances of fuel cell and the electrochemically active surface area（ECSA）. However, the fuel cell operating under dynamic load is unstable when the relative humidity is 50%, and at 50 ℃ with 100% relative humidity, applying a dynamic load has a significant influence on the fuel cell performances. Scanning electron microscopy（SEM） showed that both the upstream and middle catalyst layers of the cell were unchanged, whereas the downstream cathode catalyst layer thinned as a response to dynamic load.
文摘CHINA＇S stock market plunge and a depreciation of the yuan caused by the country＇s foreign exchange reform triggered turmoil in global markets in August. Some even claim that the yuan exchange rate will collapse, causing capital outflow to spiral out of control. Market fears about China＇s fall are more prominent than they have been in a decade.
文摘Saccular extended obstruction is generated when the anastomotic site of functional end-to-end anastomosis is extended saccularly and blocked by intestinal contents. This is a specific complication of functional end-to-end anastomosis. Saccular extended obstruction of the anastomotic site of func-tional end-to-end anastomosis causes postoperative intestinal obstruction. Saccular extended obstruction places a heavy burden on patients because surgery is necessary for treatment of intestinal obstruction due to saccular extended obstruction. However, saccular extended obstruction is not a commonly recognized complication. The greatest factor contributing to the development of saccular extended obstruction is an acute angle between the portions of the intestinal tract oral and aboral to the anastomotic site. When this angle approaches obtuse angle, preferably close to a straight line, stagnation of the intestinal contents does not occur at the anastomotic site of functional end-to-end anastomosis and saccular extended obstruction is avoided. For making the angle of anastomotic intestinal tracts obtuse or straight, it may be effective that the entry hole of stapling suture instrument creating the anastomotic stoma is closed perpendicular to the intestinal axis.
文摘The 15th China’s International Chemical Fiber Conference was held at Hangzhou, Zhejiang Province on June 10th-12th, 2009. The theme of the conference is "Financial Crisis and Chemical Fiber Industry". Hundreds of delegates
文摘Acceptor-donor-acceptor(A-D-A)type molecules,of which the novel non-fused azacyclic end-group pyrazoli-nones were modified with chlorine substitution on the phenyl ring,were synthesized.The non-fused azacyclic end-group py-razolinones have the advantages of simple synthesis steps,low cost and environmental friendliness,compared to the classical end-group dicyanomethyleneindianone.The properties of the synthesized A-D-A type molecules with non-fused azacyclic end groups were characterized by theoretical calculation,UV-vis absorption,cyclic voltammetry,X-ray diffraction and space charge limited current.It is shown that the strong UV-vis absorptions of the synthesized A-D-A type molecules are located in the wavelength range of 500~700 nm,with a moderate band gap of nearly 1.7 eV.At the same time,the influence of end-group chlorination on the properties of A-D-A type molecules was compared and explored.It is proven that this kind of A-D-A type molecule with non-fused azacyclic end groups has the potential to be applied as interfacial modified layer of the active layer in perovskite solar cell devices.
基金Supported by the Appropriate Technology Promotion Program in Chongqing,No.2023jstg005.
文摘BACKGROUND Ampullary adenocarcinoma is a rare malignant tumor of the gastrointestinal tract.Currently,only a few cases have been reported,resulting in limited information on survival.AIM To develop a dynamic nomogram using internal and external validation to predict survival in patients with ampullary adenocarcinoma.METHODS Data were sourced from the surveillance,epidemiology,and end results stat database.The patients in the database were randomized in a 7:3 ratio into training and validation groups.Using Cox regression univariate and multivariate analyses in the training group,we identified independent risk factors for overall survival and cancer-specific survival to develop the nomogram.The nomogram was validated with a cohort of patients from the First Affiliated Hospital of the Army Medical University.RESULTS For overall and cancer-specific survival,12(sex,age,race,lymph node ratio,tumor size,chemotherapy,surgical modality,T stage,tumor differentiation,brain metastasis,lung metastasis,and extension)and 6(age;surveillance,epidemiology,and end results stage;lymph node ratio;chemotherapy;surgical modality;and tumor differentiation)independent risk factors,respectively,were incorporated into the nomogram.The area under the curve values at 1,3,and 5 years,respectively,were 0.807,0.842,and 0.826 for overall survival and 0.816,0.835,and 0.841 for cancer-specific survival.The internal and external validation cohorts indicated good consistency of the nomogram.CONCLUSION The dynamic nomogram offers robust predictive efficacy for the overall and cancer-specific survival of ampullary adenocarcinoma.
文摘Let T be a tree. The set of leaves of Τ is denoted by Leaf(Τ). The subtree Τ—Leaf(Τ) of T is called the stem of Τ. A stem is called a k-ended stem if it has at most k-leaves in it. In this paper, we prove the following theorem. Let G be a connected graph and k≥2 be an integer. Let u and ν be a pair of nonadjacent vertices in G. Suppose that |NG(u)∪NG(v)|≥|G|-k-1. Then G has a spanning tree with k-ended stem if and only if G+uv has a spanning tree with k-ended stem. Moreover, the condition on |NG(u)∪NG(v)| is sharp.
