BACKGROUND As the perioperative risk of elderly patients with extremely unstable hip fractures(EUHFs)is relatively high and therapeutic effect is not satisfactory,new therapeutic strategies need to be proposed urgentl...BACKGROUND As the perioperative risk of elderly patients with extremely unstable hip fractures(EUHFs)is relatively high and therapeutic effect is not satisfactory,new therapeutic strategies need to be proposed urgently to improve the efficacy and clinical outcomes of such patients.AIM To determine the influence of two surgical treatment modalities on postoperative cognitive function(CF)and delirium in elderly patients with EUHFs.METHODS A total of 60 elderly patients consecutively diagnosed with EUHF between September 2020 and January 2022 in the Chongqing University Three Gorges Hospital were included.Of them,30 patients received conventional treatment(control group;general consultation+fracture type-guided internal fixation),and the other 30 received novel treatment(research group;perioperative multidisciplinary treatment diagnosis and treatment+individualized surgical plan+risk prediction).Information on hip function[Harris hip score(HHS)],perioperative risk of orthopedic surgery[Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity(POSSUM)],CF[Montreal cognitive assessment scale(MoCA)],postoperative delirium[mini-cognitive(Mini-Cog)],adverse events(AEs;internal fixation failure,infection,nonunion,malunion,and postoperative delirium),and clinical indicators[operation time(OT),postoperative hospital length of stay(HLOS),ambulation time,and intraoperative blood loss(IBL)]were collected from both groups for comparative analyses.RESULTS The HHS scores were similar between both groups.The POSSUM score at 6 mo after surgery was significantly lower in the research group compared with the control group,and MoCA and Mini-Cog scores were statistically higher.In addition,the overall postoperative complication rate was significantly lower in the research than in the control group,including reduced OT,postoperative HLOS,ambulation time,and IBL.CONCLUSION The new treatment modality has more clinical advantages over the conventional treatment,such as less IBL,faster functional recovery,more effectively optimized perioperative quality control,improved postoperative CF,mitigated postoperative delirium,and reduced operation-related AEs.展开更多
AIM To investigate the correlation of iodine concentration(IC) generated by spectral computed tomography(CT) with micro-vessel density(MVD) and vascular endothelial growth factor(VEGF) expression in patients with adva...AIM To investigate the correlation of iodine concentration(IC) generated by spectral computed tomography(CT) with micro-vessel density(MVD) and vascular endothelial growth factor(VEGF) expression in patients with advanced gastric carcinoma(GC).METHODS Thirty-four advanced GC patients underwent abdominal enhanced CT in the gemstone spectral imaging mode. The IC of the primary lesion in the arterial phase(AP) and venous phase(VP) were measured, and were then normalized against that in the aorta to provide the normalized IC(nI C). MVD and VEGF were detected by immunohistochemical assays, using CD34 and VEGF-A antibodies, respectively. Correlations of nI C with MVD, VEGF, and clinical-pathological features were analyzed.RESULTS Both nI Cs correlated linearly with MVD and were higher in the primary lesion site than in the normal control site, but were not correlated with VEGF expression. After stratification by clinical-pathological subtypes, nI C-AP showed a statistically significant correlation with MVD, particularly in the group with tumors at stage T4, without nodular involvement, of a mixed Lauren type, where the tumor was located at the antrum site, and occurred in female individuals. nI C-VP showed a positive correlation with MVD in the group with the tumor at stage T4 and above, had nodular involvement, was poorly differentiated, was located at the pylorus site, of a mixed and diffused Lauren subtype, and occurred in male individuals. nI C-AP and nI C-VP showed significant differences in terms of histological differentiation and Lauren subtype.CONCLUSION The IC detected by spectral CT correlated with the MVD. n IC-AP and n IC-VP can reflect angiogenesis in different pathological subgroups of advanced GC.展开更多
AIM: To investigate whether hepatitis B virus (HBV) could induce a hepatitis B virus core antigen (HBcAg)specific cytotoxic T lymphocyte (CTL) response in vitro by dendritic cells (DCs) transduced with lentiv...AIM: To investigate whether hepatitis B virus (HBV) could induce a hepatitis B virus core antigen (HBcAg)specific cytotoxic T lymphocyte (CTL) response in vitro by dendritic cells (DCs) transduced with lentiviral vector-encoding ubiquitinated hepatitis B virus core antigen (LV-Ub-HBcAg).METHODS: Recombinant LV-Ub-HBcAg were transfected into highly susceptible 293 T cells to obtain high virus titres, Bone marrow-derived DCs isolated from BALB/c mice were cultured with recombinant granulocyte-macrophage colony-stimulating factor and recombinant interleukin (IL)-4. LV-Ub-HBcAg, lentiviral vector-encoding hepatitis B virus core antigen (LV-HBcAg), lentiviral vector (LV) or lipopolysaccharide were added to induce DC maturation, and the DC phenotypes were analyzed by flow cytometry. The level of IL-12 in the supernatant was detected by enzyme-linked immunosorbent assay (ELISA). T lymphocytes were proliferated using Cell Counting Kit-8. DCs were cultured and induced to mature using different LVs, and co-cultured with allogeneic T cells to detect the secretion levels of IL-2, IL-4, IL-10and interferon-γ in the supernatants of T cells by ELISA. Intracellular cytokines of proliferative T cells were analyzed by flow cytometry, and specific CTL activity was measured by a lactate dehydrogenase release assay.RESULTS: LV-Ub-HBcAg-induced DCs secreted more IL-12 and upregulated the expression of CD80, CD86 and major histocompatibility class ]I, DCs sensitised by different LVs effectively promoted cytokine secretion; the levels of IL-2 and interferon-y induced by LV-Ub- HBcAg were higher than those induced by LV-HBcAg, Compared with LV-HBcAg-transduced DCs, LV-Ub- HBcAg-transduced DCs more efficiently stimulated the proliferation of T lymphocytes and generated HBcAgspecific cytotoxic T lymphocytes.CONCLUSION: LV-Ub-HBcAg effectively induced DC maturation. The mature DCs efficiently induced T cell polarisation to Thl and generated HBcAg-specific CTLs.展开更多
(Zr41.2Ti13.sCu12.sNi10Be22.5)100-~Nb~ (at%, x=0 and 8) bulk metallic glasses (BMGs) were coated on the surface of Q195 steel wires by a continuous coating process. The potentiodynamic polarization tests of thes...(Zr41.2Ti13.sCu12.sNi10Be22.5)100-~Nb~ (at%, x=0 and 8) bulk metallic glasses (BMGs) were coated on the surface of Q195 steel wires by a continuous coating process. The potentiodynamic polarization tests of these BMGs were conducted in 3.5wt% NaC1 aqueous solution. It is found that the addition of 8at% Nb into Zr41.2Ti13.sCu12.sNi10Be22.5 alloy results in the improvement of corrosion resistance with the pitting potential of -52 mV, the open circuit potential of-446 mV, and the corrosion current density of 9.86x 10-6 mA/cm2. This may be attributed to that Nb is beneficial to passivate and stabilize Zr and Ti.展开更多
(Mg66.aZn28.8Cas)10o-xCux (at%, x = 0, 1, 3, and 5) bulk metallic glasses (BMGs) of 2 mm in diameter were prepared by the conventional copper mold injection casting method. Besides, the influence of Cu content o...(Mg66.aZn28.8Cas)10o-xCux (at%, x = 0, 1, 3, and 5) bulk metallic glasses (BMGs) of 2 mm in diameter were prepared by the conventional copper mold injection casting method. Besides, the influence of Cu content on the microstructure, thermal stability, mechanical properties, and corrosion behavior of Mg-Zn--Ca BMGs was investigated. It is found that the addition of Cu decreases the glass-forming ability of Mg-Zn-Ca BMGs. Crystalline phases are precipitated at a higher Cu content, larger than 3at%. The compressive fracture strength of Mg-Zn-Ca BMGs is enhanced by the addition of Cu. With the formation of in-situ composites, the compressive strength of the Mg-Zn-Ca alloy with 3at% Cu reaches 979 MPa, which is the highest strength among the Mg-Zn-Ca alloys. Furthermore, the addition of Cu also results in the increase of corrosion potential and the decrease of corrosion current density in Mg-Zn-Ca BMGs, thereby delaying their biodegradability.展开更多
Two types of ultralow carbon steel weld metals(with and without added Cu-Nb) were prepared using gas metal arc welding(GMAW) to investigate the correlation between the microstructure and mechanical properties of weld ...Two types of ultralow carbon steel weld metals(with and without added Cu-Nb) were prepared using gas metal arc welding(GMAW) to investigate the correlation between the microstructure and mechanical properties of weld metals.The results of microstructure characterization showed that the weld metal without Cu-Nb was mainly composed of acicular ferrite(AF), lath bainite(LB), and granular bainite(GB).In contrast, adding Cu-Nb to the weld metal caused an evident transformation of martensite and grain coarsening.Both weld metals had a high tensile strength(more than 950 MPa) and more than 17% elongation;however, their values of toughness deviated greatly,with a difference of approximately 40 J at-50℃.Analysis of the morphologies of the fracture surfaces and secondary cracks further revealed the correlation between the microstructure and mechanical properties.The effects of adding Cu and Nb on the microstructure and mechanical properties of the weld metal are discussed;the indication is that adding Cu-Nb increases the hardenability and grain size of the weld metal and thus deteriorates the toughness.展开更多
A continuous production process was developed for coating bulk metallic glasses on the metallic wire surface. The effects of processing parameters, including the drawing velocity and coating temperature, on the coatin...A continuous production process was developed for coating bulk metallic glasses on the metallic wire surface. The effects of processing parameters, including the drawing velocity and coating temperature, on the coating thickness were investigated. It is found that the coating thickness increases with the increase in drawing velocity but decreases with the increase in coating temperature. A fluid mechanical model was developed to quantify the coating thickness under various processing conditions. By using this theoretical model, the coating thickness was calculated, and the calculated values are in good agreement with the experimental data.展开更多
Copper-coated aluminum wires exhibit good electrical conductivity, high thermal conductivity, low contact resistance of copper and low density, and provide economic advantages over aluminum. However, there are some pr...Copper-coated aluminum wires exhibit good electrical conductivity, high thermal conductivity, low contact resistance of copper and low density, and provide economic advantages over aluminum. However, there are some problems in the manufacring processes of hot-dip copper-coated aluminum wires, such as the difficulties in controlling coating process. In this work, the hot-dip copper-coating method of aluminum wires was investigated for producing copper-coated aluminum wire composites. The interface microstructure between the aluminum wire and the copper coating layer was analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spec- trometry (EDS). Five different fluxing agents were tested. Experimental results show that appropriate conditions for the hot-dip process are determined as the liquid copper temperature of 1085℃ and the treatment time less than 1 s. A success in hot-dip copper-coated aluminum wires is achieved by hot-dipping a low-melting-point metal into a high-melting-point metal liquid, which is significant for the further devel- opment and application of copper-coated aluminum wire composites.展开更多
Background:Amyloid-β deposition and accumulation of autophagic vacuoles are pathologic features of Alzheimer's disease (AD).Dysregulation of the endosomal-autophagic-lysosomal (EAL) pathway,which impairs amyloi...Background:Amyloid-β deposition and accumulation of autophagic vacuoles are pathologic features of Alzheimer's disease (AD).Dysregulation of the endosomal-autophagic-lysosomal (EAL) pathway,which impairs amyloid precursor protein processing,is one of the earliest changes in AD.However,the precise role of EAL pathway in neurodegeneration remains unclear.This study aimed to investigate the role of EAL pathway in AD and further study the mechanism of EAL dysfunction.Methods:We used 3-,7-,and 12-month-old APPswe/PSEN1dE9 (APP/PS1) mice to model different stages of AD with age-and gender-matched wild-type littermates as controls (4-7 mice per group) and detected the changes of EAL markers,endosomal organizers Rab5 and Rab7,autophagosome marker LC3B,and lysosomal proteins Lamp 1/2 in cortex and hippocampus by immunohistochemistry and Western blotting analysis.To further explore the mechanism of EAL dysregulation in AD,components of the class Ⅲ phosphatidylinositol 3-kinase (PI3KC3) complex,activators ofRab7 (Beclin1 and UVRAG),and the negative regulator of Rab7 (Rubicon) were also measured in this two brain regions.Results:In 7-month-old APP/PS1 brain that amyloid beta initiated to accumulate intracellularly,EAL pathway,and related PI3KC3 members,UVRAG and Beclin1 were upregulated both in cortex and hippocampus (all P 〈 0.05).By the age of 12 months old,when abundant amyloid plaques formed,EAL markers,UVRAG,and Beclin 1 were also upregulated in the cortex (all P 〈 0.05).However,Rab7 was decreased significantly (P =0.0447),accompanied by a reduction of its activating PI3KC complex component Beclin1 (P =0.0215) and enhancement of its inhibiting component Rubicon (P =0.0055) in the hippocampus.Conclusions:Our study implies that EAL pathway,represented as Rab7 and its PI3KC3 regulators' expressions,showed temporal and spatial variation in brains at different stages of AD.It provides new insights into the role of EAL pathway in pathogenesis and indicates potential therapeutic targets in neurodegenerative diseases.展开更多
Although several theoretical calculation methods for high-pressure jet are available,there is currently no theoretical model for the high-pressure CO_(2)jet based on the high-precision equation of state(EOS).To invest...Although several theoretical calculation methods for high-pressure jet are available,there is currently no theoretical model for the high-pressure CO_(2)jet based on the high-precision equation of state(EOS).To investigate the flow field of the high-pressure CO_(2)jet in cases of the composite rock-breaking under the high-pressure CO_(2)Jet and PDC cutter,a semi-analytical approach of the high-pressure CO_(2)jet is developed based on the Span-Wagner EOS and CO_(2)jet theory.The semi-analytical calculations and the physical property calculations under the action of the high-pressure CO_(2)jet are conducted with consideration of the jet pressure,the jet distance,the nozzle diameter and the jet angle.The results indicate that the distribution of the physical properties calculated by the semi-analytical approaches is similar to that obtained by experimental monitoring and numerical simulation,which indicates that the calculation method of the high-pressure CO_(2)jet presented in this paper is effective and reliable.The properties of the CO_(2)jet obtained by the theoretical calculation see a significant difference between the initial region and the jet impact region.At the temperature of 300 K,the increase of the initial pressure can effectively increase the impact force and the cooling ability of the jet.The proportion of the jet core lengths in the jet on the axis increases with the increase of the ratio of the nozzle diameter to the jet length,accompanied with the increase of the impact force of the jet.The increase of the jet angle can effectively increase the impacting force of the jet,but hampers the fluid diffusion.The study combines the theoretical calculation of the jet with the calculation of the physical properties of the high-pressure CO_(2),for comprehensively understanding the CO_(2)jet field in the composite rock-breaking under the action of the high-pressure CO_(2)jet and PDC cutter.This theoretical calculation of the CO_(2)jet based on the high-precision EOS provides an option for the convenient calculation of the CO_(2)drilling in practical engineering.展开更多
Gold nanoparticles(AuNPs)colorimetric assays based on distance-dependent optical characteristics have been widely employed for bioanalysis.However,this assay is not effective for visually detecting low-concentration t...Gold nanoparticles(AuNPs)colorimetric assays based on distance-dependent optical characteristics have been widely employed for bioanalysis.However,this assay is not effective for visually detecting low-concentration targets due to the faint color change.Here,we developed a handheld nano-centrifugal device which could separate the crosslinked and non-crosslinked AuNPs.Results showed that the handheld nano-centrifugal device could easily reach more than 6000 r/min within 10 s simply by stretching and tightening the coiled rope in an appropriate rhythm.Further,combined with the CRISPR/Cas12a nucleic acids recognition system,a field-deployable colorimetric platform termed handheld nano-centrifugal device assisted CRISPR/Cas12a(Hand-CRISPR)has been validated.Moreover,clinical diagnostics applications for Epstein-Barr virus(EBV)and severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)detection with high sensitivity and accuracy(100%consistency with reverse transcription quantitative real-time polymerase chain reaction(RT-qPCR)test results)have been demonstrated.Overall,the Hand-CRISPR platform showed great promise in point-of-care-test(POCT)application,expected to become a powerful supplement to the standard nucleic acid testing method in remote or poverty-stricken areas.展开更多
A single crystal Cu-1wt.%Fe alloy with finely dispersed iron-rich nanoparticles which keep coherent interface with the copper matrix was prepared under directional solidification.Formation of nanoparticles in the allo...A single crystal Cu-1wt.%Fe alloy with finely dispersed iron-rich nanoparticles which keep coherent interface with the copper matrix was prepared under directional solidification.Formation of nanoparticles in the alloy melt was investigated by performing differential scanning calorimeter tests and designed water quenching experiment at a certain temperature.Results show that iron-rich nanoparticles are formed in the Cu-1wt.%Fe alloy melt before primaryα-Cu forms,which is not consistent with equilibrium phase diagram.Mechanism that iron-rich nanoparticles are uniformly captured in the matrix was described,which is that numerous nanoparticles follow Brownian motions and are engulfed in the solidified matrix which makes it possible to form uniformly distributed nanoparticles reinforced single crystal Cu-1wt.%Fe alloy.展开更多
基金Supported by the Chongqing Medical Scientific Research Project(Joint Project of Chongqing Health Commission and Science and Technology Bureau),No.2020FYYX211Medical Research Project of Wanzhou District(Joint Project of Health Commission and Science and Technology Bureau),No.wzstc-kw2020023.
文摘BACKGROUND As the perioperative risk of elderly patients with extremely unstable hip fractures(EUHFs)is relatively high and therapeutic effect is not satisfactory,new therapeutic strategies need to be proposed urgently to improve the efficacy and clinical outcomes of such patients.AIM To determine the influence of two surgical treatment modalities on postoperative cognitive function(CF)and delirium in elderly patients with EUHFs.METHODS A total of 60 elderly patients consecutively diagnosed with EUHF between September 2020 and January 2022 in the Chongqing University Three Gorges Hospital were included.Of them,30 patients received conventional treatment(control group;general consultation+fracture type-guided internal fixation),and the other 30 received novel treatment(research group;perioperative multidisciplinary treatment diagnosis and treatment+individualized surgical plan+risk prediction).Information on hip function[Harris hip score(HHS)],perioperative risk of orthopedic surgery[Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity(POSSUM)],CF[Montreal cognitive assessment scale(MoCA)],postoperative delirium[mini-cognitive(Mini-Cog)],adverse events(AEs;internal fixation failure,infection,nonunion,malunion,and postoperative delirium),and clinical indicators[operation time(OT),postoperative hospital length of stay(HLOS),ambulation time,and intraoperative blood loss(IBL)]were collected from both groups for comparative analyses.RESULTS The HHS scores were similar between both groups.The POSSUM score at 6 mo after surgery was significantly lower in the research group compared with the control group,and MoCA and Mini-Cog scores were statistically higher.In addition,the overall postoperative complication rate was significantly lower in the research than in the control group,including reduced OT,postoperative HLOS,ambulation time,and IBL.CONCLUSION The new treatment modality has more clinical advantages over the conventional treatment,such as less IBL,faster functional recovery,more effectively optimized perioperative quality control,improved postoperative CF,mitigated postoperative delirium,and reduced operation-related AEs.
基金Supported by the National Natural Science Foundation of China,No.81271573
文摘AIM To investigate the correlation of iodine concentration(IC) generated by spectral computed tomography(CT) with micro-vessel density(MVD) and vascular endothelial growth factor(VEGF) expression in patients with advanced gastric carcinoma(GC).METHODS Thirty-four advanced GC patients underwent abdominal enhanced CT in the gemstone spectral imaging mode. The IC of the primary lesion in the arterial phase(AP) and venous phase(VP) were measured, and were then normalized against that in the aorta to provide the normalized IC(nI C). MVD and VEGF were detected by immunohistochemical assays, using CD34 and VEGF-A antibodies, respectively. Correlations of nI C with MVD, VEGF, and clinical-pathological features were analyzed.RESULTS Both nI Cs correlated linearly with MVD and were higher in the primary lesion site than in the normal control site, but were not correlated with VEGF expression. After stratification by clinical-pathological subtypes, nI C-AP showed a statistically significant correlation with MVD, particularly in the group with tumors at stage T4, without nodular involvement, of a mixed Lauren type, where the tumor was located at the antrum site, and occurred in female individuals. nI C-VP showed a positive correlation with MVD in the group with the tumor at stage T4 and above, had nodular involvement, was poorly differentiated, was located at the pylorus site, of a mixed and diffused Lauren subtype, and occurred in male individuals. nI C-AP and nI C-VP showed significant differences in terms of histological differentiation and Lauren subtype.CONCLUSION The IC detected by spectral CT correlated with the MVD. n IC-AP and n IC-VP can reflect angiogenesis in different pathological subgroups of advanced GC.
基金Supported by Natural Science Foundation of Shanghai,No.11ZR1427100
文摘AIM: To investigate whether hepatitis B virus (HBV) could induce a hepatitis B virus core antigen (HBcAg)specific cytotoxic T lymphocyte (CTL) response in vitro by dendritic cells (DCs) transduced with lentiviral vector-encoding ubiquitinated hepatitis B virus core antigen (LV-Ub-HBcAg).METHODS: Recombinant LV-Ub-HBcAg were transfected into highly susceptible 293 T cells to obtain high virus titres, Bone marrow-derived DCs isolated from BALB/c mice were cultured with recombinant granulocyte-macrophage colony-stimulating factor and recombinant interleukin (IL)-4. LV-Ub-HBcAg, lentiviral vector-encoding hepatitis B virus core antigen (LV-HBcAg), lentiviral vector (LV) or lipopolysaccharide were added to induce DC maturation, and the DC phenotypes were analyzed by flow cytometry. The level of IL-12 in the supernatant was detected by enzyme-linked immunosorbent assay (ELISA). T lymphocytes were proliferated using Cell Counting Kit-8. DCs were cultured and induced to mature using different LVs, and co-cultured with allogeneic T cells to detect the secretion levels of IL-2, IL-4, IL-10and interferon-γ in the supernatants of T cells by ELISA. Intracellular cytokines of proliferative T cells were analyzed by flow cytometry, and specific CTL activity was measured by a lactate dehydrogenase release assay.RESULTS: LV-Ub-HBcAg-induced DCs secreted more IL-12 and upregulated the expression of CD80, CD86 and major histocompatibility class ]I, DCs sensitised by different LVs effectively promoted cytokine secretion; the levels of IL-2 and interferon-y induced by LV-Ub- HBcAg were higher than those induced by LV-HBcAg, Compared with LV-HBcAg-transduced DCs, LV-Ub- HBcAg-transduced DCs more efficiently stimulated the proliferation of T lymphocytes and generated HBcAgspecific cytotoxic T lymphocytes.CONCLUSION: LV-Ub-HBcAg effectively induced DC maturation. The mature DCs efficiently induced T cell polarisation to Thl and generated HBcAg-specific CTLs.
基金supports by the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20100006120020)the National Nature Science Foundation of China(Nos.51071018and51271018)
文摘(Zr41.2Ti13.sCu12.sNi10Be22.5)100-~Nb~ (at%, x=0 and 8) bulk metallic glasses (BMGs) were coated on the surface of Q195 steel wires by a continuous coating process. The potentiodynamic polarization tests of these BMGs were conducted in 3.5wt% NaC1 aqueous solution. It is found that the addition of 8at% Nb into Zr41.2Ti13.sCu12.sNi10Be22.5 alloy results in the improvement of corrosion resistance with the pitting potential of -52 mV, the open circuit potential of-446 mV, and the corrosion current density of 9.86x 10-6 mA/cm2. This may be attributed to that Nb is beneficial to passivate and stabilize Zr and Ti.
基金financially supported the National Natural Science Foundation of China(Nos.51071018 and 51271018)
文摘(Mg66.aZn28.8Cas)10o-xCux (at%, x = 0, 1, 3, and 5) bulk metallic glasses (BMGs) of 2 mm in diameter were prepared by the conventional copper mold injection casting method. Besides, the influence of Cu content on the microstructure, thermal stability, mechanical properties, and corrosion behavior of Mg-Zn--Ca BMGs was investigated. It is found that the addition of Cu decreases the glass-forming ability of Mg-Zn-Ca BMGs. Crystalline phases are precipitated at a higher Cu content, larger than 3at%. The compressive fracture strength of Mg-Zn-Ca BMGs is enhanced by the addition of Cu. With the formation of in-situ composites, the compressive strength of the Mg-Zn-Ca alloy with 3at% Cu reaches 979 MPa, which is the highest strength among the Mg-Zn-Ca alloys. Furthermore, the addition of Cu also results in the increase of corrosion potential and the decrease of corrosion current density in Mg-Zn-Ca BMGs, thereby delaying their biodegradability.
基金financially supported by the Fundamental Research Funds for the Central Universities (No.FRF-AT-19-002)the Domain Foundation of Equipment Advance Research of the 13th Five-year Plan (No.61409220121)the National Natural Science Foundation of China (No.51971031)。
文摘Two types of ultralow carbon steel weld metals(with and without added Cu-Nb) were prepared using gas metal arc welding(GMAW) to investigate the correlation between the microstructure and mechanical properties of weld metals.The results of microstructure characterization showed that the weld metal without Cu-Nb was mainly composed of acicular ferrite(AF), lath bainite(LB), and granular bainite(GB).In contrast, adding Cu-Nb to the weld metal caused an evident transformation of martensite and grain coarsening.Both weld metals had a high tensile strength(more than 950 MPa) and more than 17% elongation;however, their values of toughness deviated greatly,with a difference of approximately 40 J at-50℃.Analysis of the morphologies of the fracture surfaces and secondary cracks further revealed the correlation between the microstructure and mechanical properties.The effects of adding Cu and Nb on the microstructure and mechanical properties of the weld metal are discussed;the indication is that adding Cu-Nb increases the hardenability and grain size of the weld metal and thus deteriorates the toughness.
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20100006120020)the National Natural Science Foundation of China(Nos.51010001,51071018,and 51001009)+1 种基金the Program of Introducing Talents of Discipline to Universities(the 111 Project,No.B07003)the Program for Changjiang Scholars and Innovative Research Team in Universities of the Ministry of Education of China
文摘A continuous production process was developed for coating bulk metallic glasses on the metallic wire surface. The effects of processing parameters, including the drawing velocity and coating temperature, on the coating thickness were investigated. It is found that the coating thickness increases with the increase in drawing velocity but decreases with the increase in coating temperature. A fluid mechanical model was developed to quantify the coating thickness under various processing conditions. By using this theoretical model, the coating thickness was calculated, and the calculated values are in good agreement with the experimental data.
基金financially supported by the Research Fund for the Doctoral Program of Higher Education of China(No.20100006120020)
文摘Copper-coated aluminum wires exhibit good electrical conductivity, high thermal conductivity, low contact resistance of copper and low density, and provide economic advantages over aluminum. However, there are some problems in the manufacring processes of hot-dip copper-coated aluminum wires, such as the difficulties in controlling coating process. In this work, the hot-dip copper-coating method of aluminum wires was investigated for producing copper-coated aluminum wire composites. The interface microstructure between the aluminum wire and the copper coating layer was analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spec- trometry (EDS). Five different fluxing agents were tested. Experimental results show that appropriate conditions for the hot-dip process are determined as the liquid copper temperature of 1085℃ and the treatment time less than 1 s. A success in hot-dip copper-coated aluminum wires is achieved by hot-dipping a low-melting-point metal into a high-melting-point metal liquid, which is significant for the further devel- opment and application of copper-coated aluminum wire composites.
基金This work was supported by a grant of National Natural Science Foundation of China (No. 81271406).
文摘Background:Amyloid-β deposition and accumulation of autophagic vacuoles are pathologic features of Alzheimer's disease (AD).Dysregulation of the endosomal-autophagic-lysosomal (EAL) pathway,which impairs amyloid precursor protein processing,is one of the earliest changes in AD.However,the precise role of EAL pathway in neurodegeneration remains unclear.This study aimed to investigate the role of EAL pathway in AD and further study the mechanism of EAL dysfunction.Methods:We used 3-,7-,and 12-month-old APPswe/PSEN1dE9 (APP/PS1) mice to model different stages of AD with age-and gender-matched wild-type littermates as controls (4-7 mice per group) and detected the changes of EAL markers,endosomal organizers Rab5 and Rab7,autophagosome marker LC3B,and lysosomal proteins Lamp 1/2 in cortex and hippocampus by immunohistochemistry and Western blotting analysis.To further explore the mechanism of EAL dysregulation in AD,components of the class Ⅲ phosphatidylinositol 3-kinase (PI3KC3) complex,activators ofRab7 (Beclin1 and UVRAG),and the negative regulator of Rab7 (Rubicon) were also measured in this two brain regions.Results:In 7-month-old APP/PS1 brain that amyloid beta initiated to accumulate intracellularly,EAL pathway,and related PI3KC3 members,UVRAG and Beclin1 were upregulated both in cortex and hippocampus (all P 〈 0.05).By the age of 12 months old,when abundant amyloid plaques formed,EAL markers,UVRAG,and Beclin 1 were also upregulated in the cortex (all P 〈 0.05).However,Rab7 was decreased significantly (P =0.0447),accompanied by a reduction of its activating PI3KC complex component Beclin1 (P =0.0215) and enhancement of its inhibiting component Rubicon (P =0.0055) in the hippocampus.Conclusions:Our study implies that EAL pathway,represented as Rab7 and its PI3KC3 regulators' expressions,showed temporal and spatial variation in brains at different stages of AD.It provides new insights into the role of EAL pathway in pathogenesis and indicates potential therapeutic targets in neurodegenerative diseases.
基金This work was supported by the Sichuan Science and Technology Program(Grant No.2021JDRC0114)the Starting Project of Southwest Petroleum University(Grant No.2019QHZ009)+2 种基金the China Postdoctoral Science Foundation(Grant No.2020M673285)the Open Project Program of Key Laboratory of Groundwater Resources and Environment,Ministry of Education,Jilin University(Grant No.202005009KF)the Chinese Scholarship Council funding(Grant No.202008515107).
文摘Although several theoretical calculation methods for high-pressure jet are available,there is currently no theoretical model for the high-pressure CO_(2)jet based on the high-precision equation of state(EOS).To investigate the flow field of the high-pressure CO_(2)jet in cases of the composite rock-breaking under the high-pressure CO_(2)Jet and PDC cutter,a semi-analytical approach of the high-pressure CO_(2)jet is developed based on the Span-Wagner EOS and CO_(2)jet theory.The semi-analytical calculations and the physical property calculations under the action of the high-pressure CO_(2)jet are conducted with consideration of the jet pressure,the jet distance,the nozzle diameter and the jet angle.The results indicate that the distribution of the physical properties calculated by the semi-analytical approaches is similar to that obtained by experimental monitoring and numerical simulation,which indicates that the calculation method of the high-pressure CO_(2)jet presented in this paper is effective and reliable.The properties of the CO_(2)jet obtained by the theoretical calculation see a significant difference between the initial region and the jet impact region.At the temperature of 300 K,the increase of the initial pressure can effectively increase the impact force and the cooling ability of the jet.The proportion of the jet core lengths in the jet on the axis increases with the increase of the ratio of the nozzle diameter to the jet length,accompanied with the increase of the impact force of the jet.The increase of the jet angle can effectively increase the impacting force of the jet,but hampers the fluid diffusion.The study combines the theoretical calculation of the jet with the calculation of the physical properties of the high-pressure CO_(2),for comprehensively understanding the CO_(2)jet field in the composite rock-breaking under the action of the high-pressure CO_(2)jet and PDC cutter.This theoretical calculation of the CO_(2)jet based on the high-precision EOS provides an option for the convenient calculation of the CO_(2)drilling in practical engineering.
基金This work was supported by the National Natural Science Foundation of China(91959128,21874049,81772246)the Special Project of Science and Technology Development of Guangdong Province(2017B020207011)+1 种基金the Key Research and Development Plan of Hubei Province(2020BCA090)the Open Funds of the State Key Laboratory of Electroanalytical Chemistry(SKLEAC202001).
文摘Gold nanoparticles(AuNPs)colorimetric assays based on distance-dependent optical characteristics have been widely employed for bioanalysis.However,this assay is not effective for visually detecting low-concentration targets due to the faint color change.Here,we developed a handheld nano-centrifugal device which could separate the crosslinked and non-crosslinked AuNPs.Results showed that the handheld nano-centrifugal device could easily reach more than 6000 r/min within 10 s simply by stretching and tightening the coiled rope in an appropriate rhythm.Further,combined with the CRISPR/Cas12a nucleic acids recognition system,a field-deployable colorimetric platform termed handheld nano-centrifugal device assisted CRISPR/Cas12a(Hand-CRISPR)has been validated.Moreover,clinical diagnostics applications for Epstein-Barr virus(EBV)and severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)detection with high sensitivity and accuracy(100%consistency with reverse transcription quantitative real-time polymerase chain reaction(RT-qPCR)test results)have been demonstrated.Overall,the Hand-CRISPR platform showed great promise in point-of-care-test(POCT)application,expected to become a powerful supplement to the standard nucleic acid testing method in remote or poverty-stricken areas.
文摘A single crystal Cu-1wt.%Fe alloy with finely dispersed iron-rich nanoparticles which keep coherent interface with the copper matrix was prepared under directional solidification.Formation of nanoparticles in the alloy melt was investigated by performing differential scanning calorimeter tests and designed water quenching experiment at a certain temperature.Results show that iron-rich nanoparticles are formed in the Cu-1wt.%Fe alloy melt before primaryα-Cu forms,which is not consistent with equilibrium phase diagram.Mechanism that iron-rich nanoparticles are uniformly captured in the matrix was described,which is that numerous nanoparticles follow Brownian motions and are engulfed in the solidified matrix which makes it possible to form uniformly distributed nanoparticles reinforced single crystal Cu-1wt.%Fe alloy.