The aim of the present study was to explore the effects of annexin A1(ANXA1) mimetic peptide AC2-26 on sepsis-induced cardiomyocyte apoptosis in vivo and in vitro and the underlying mechanisms.In the in vivo study,a r...The aim of the present study was to explore the effects of annexin A1(ANXA1) mimetic peptide AC2-26 on sepsis-induced cardiomyocyte apoptosis in vivo and in vitro and the underlying mechanisms.In the in vivo study,a rat septic model was established by the cecal ligation and puncture (CLP).The rats were divided into control group,sepsis group and AC2-26 group.The rats in the AC2-26 group were intraperitoneally injected with AC2-26(1mg/kg)2h before CLP,and those in the control group and sepsis group were injected with the same volume of normal saline.The myocardial tissue was examined by hematoxylin and eosin (HE)staining and transmission electron microscopy (TEM).Furthermore,myocardial apoptosis was measured by terminal dUTP nick end-labeling (TUNEL)assay.In the in vitro study,H9C2cells were cultured and divided into three groups:control group,in which cells were only given the basic culture medium;LPS group,in which cells were treated with 10μg/mL LPS;AC2-26 group,in which cells were treated with 0.5μmol/L AC2-262h before 10μg/mL LPS was given.The apoptosis of H9C2 cells was detected by flow cytometry.The levels of lipoxin A4 receptor (LXA4),phosphoinositide3-kinase (PI3K)and protein kinase B (PKB or AKT)protein were measured by Western blotting, the activity of NF-KB and the level of TNF-α by ELISA and the activities of caspase-3/8by using the caspase activity kits.The in vivo study showed that the myocardial pathological damage and myocardial ultrastructural damage were significantly alleviated and the myocardial apoptosis significantly decreased in the AC2-26 group as compared with the sepsis group (P<0.05 for all). The in vivo study revealed that the apoptosis of H9C2 cells was profoundly ameliorated in the AC2-26 group relative to the sepsis group (P<0.05).The protein expression levels of LXA4 were significantly up-regulated,and those of PI3K and AKT prominently down-regulated in the AC2-26 group when compared with those in the LPS group (P<0.05 for all).The activity of NF-κB was greatly inhibited and the level of TNF-α markedly decreased in the AC2-26 group as compared with those in the LPS group (P<0.05 for all).AC2-26 treatment also significantly suppressed the activities of caspase-3/8 in H9C2 cells.In conclusion,these findings suggest that AC2-26 may alleviate the sepsis-induced cardiomyocyte apoptosis in vivo and in vivo through the LXA4/PI3K/ AKT signaling pathway.展开更多
A novel flux charging method and a crucible quenching method were employed to study the mechanism of solid fluxes refining method regarding the removal of oxide inclusions(Al_2O_3) from molten aluminum. Electrochemica...A novel flux charging method and a crucible quenching method were employed to study the mechanism of solid fluxes refining method regarding the removal of oxide inclusions(Al_2O_3) from molten aluminum. Electrochemical polishing method was adopted to prepare surfaces of the samples. Through experiments, the morphology of the residual solidified flux in the solidified samples as well as the wetting action of the molten flux during refining were observed for the first time. Three wetting regimes denoted by absorbing regime, engulfing regime and penetration regime correlating with the removal of oxide films(the most typical and common oxide inclusions in molten aluminum) were proposed in terms of different types and distributions of oxide films and different size ratios of the molten flux to oxide films. Particularly, from a thermodynamic point of view, for the first time, the penetration regime provided concrete evidence that the practical oxide inclusions can be wet by molten flux under ambient fluid of molten aluminum. A spreading model was proposed, according to which ingredients and size parameters of practical solid fluxes can be optimized.展开更多
Previous studies have shown that sirtuin 1(SIRT1) reduces the production of neuronal amyloid beta(Aβ) and inhibits the inflammatory response of glial cells, thereby generating a neuroprotective effect against Aβ neu...Previous studies have shown that sirtuin 1(SIRT1) reduces the production of neuronal amyloid beta(Aβ) and inhibits the inflammatory response of glial cells, thereby generating a neuroprotective effect against Aβ neurotoxicity in animal models of Alzheimer's disease. However, the protective effect of SIRT1 on astrocytes is still under investigation. This study established a time point model for the clearance of Aβ in primary astrocytes. Results showed that 12 hours of culture was sufficient for endocytosis of oligomeric Aβ, and 36 hours sufficient for effective degradation. Immunofluorescence demonstrated that Aβ degradation in primary astrocytes relies on lysosome function. Enzymatic agonists or SIRT1 inhibitors were used to stimulate cells over a concentration gradient. Aβ was co-cultured for 36 hours in medium. Western blot assay results under different conditions revealed that SIRT1 relies on its deacetylase activity to promote intracellular Aβ degradation. The experiment further screened SIRT1 using quantitative proteomics to investigate downstream, differentially expressed proteins in the Aβ degradation pathway and selected the ones related to enzyme activity of SIRT1. Most of the differentially expressed proteins detected are close to the primary astrocyte lysosomal pathway. Immunofluorescence staining demonstrated that SIRT1 relies on its deacetylase activity to upregulate lysosome number in primary astrocytes. Taken together, these findings confirm that SIRT1 relies on its deacetylase activity to upregulate lysosome number, thereby facilitating oligomeric Aβ degradation in primary astrocytes.展开更多
The effect of solidification cooling rate on the size and distribution of inclusions in 12%Cr stainless steel was investigated. A wide range of solidification cooling rates(from 0.05 to 106 K·s-1) was achieved us...The effect of solidification cooling rate on the size and distribution of inclusions in 12%Cr stainless steel was investigated. A wide range of solidification cooling rates(from 0.05 to 106 K·s-1) was achieved using various solidification processes, including conventional casting, laser remelting, and melt spinning. The size and distribution of inclusions in the steel were observed and statistically collected. For comparison, mathematical models were used to calculate the sizes of inclusions at different solidification cooling rates. Both the statistical size determined from observations and that predicted from calculations tended to decrease with increasing cooling rate; however, the experimental and calculated results did not agree well with each other at excessively high or low cooling rate. The reasons for this discrepancy were theoretically analyzed. For the size distribution of inclusions, the effect of cooling rate on the number densities of large-sized(> 2 μm) inclusions and small-sized(≤ 2 μm) inclusions were distinct. The number density of inclusions larger than 1 μm was not affected when the cooing rate was less than or equal to 6 K·s-1 because inclusion precipitation was suppressed by the increased cooling rate.展开更多
Donor-derived infection(DDI)associated with Scedosporium spp is extremely rare,and results in a very poor prognosis.The present study reports a probable DDI due to Scedosporium boydii(S.boydii)from a donor with neurop...Donor-derived infection(DDI)associated with Scedosporium spp is extremely rare,and results in a very poor prognosis.The present study reports a probable DDI due to Scedosporium boydii(S.boydii)from a donor with neuropsychiatric systemic lupus erythematosus.Two recipients developed Scedosporiosis after kidney transplantation from the same donor.Recipient 1 died of central nervous system infection due to S.boydii based on the clinical presentations,and the positive metagenomic next-generation sequencing(mNGS)and culture results for the cerebrospinal fluid.The other recipient with urinary tract obstruction due to S.boydii,which was identified through the positive culture and mNGS results of the removed stents,was successfully treated by stent replacement and voriconazole administration.Undiagnosed disseminated donor infection and the transmission of S.boydii should be given attention,particularly when the donor and recipients have primary immunodeficiency disease.The screening of donors and recipients for S.boydii using mNGS may be helpful in guiding antifungal prophylaxis and treatment recipients,due to its higher sensitivity and shorter diagnostic time relative to other traditional techniques.展开更多
BACKGROUND Precleaning is a key step in endoscopic reprocessing.AIM To develop an effective and economic endoscope cleaning method by using a disposable endoscope bedside precleaning kit.METHODS Altogether,228 used ga...BACKGROUND Precleaning is a key step in endoscopic reprocessing.AIM To develop an effective and economic endoscope cleaning method by using a disposable endoscope bedside precleaning kit.METHODS Altogether,228 used gastrointestinal endoscopes were selected from five high-volume endoscopy units and precleaned by a traditional precleaning bucket(group T)or a disposable endoscope bedside precleaning kit(group D).Each group was further subdivided based on the replacement frequency of the cleaning solution,which was replaced every time in subgroups T1 and D1 and every several times in subgroups Ts and Ds.The adenosine triphosphate(ATP)level and residual proteins were measured three times:Before and after precleaning and after manual cleaning.RESULTS After precleaning,the precleaning kit significantly reduced the ATP levels(P=0.034)and has a more stable ATP clearance rate than the traditional precleaning bucket.The precleaning kit also saved a quarter of the cost of enzymatic detergent used during the precleaning process.After manual cleaning,the ATP levels were also significantly lower in the precleaning kit group than in the traditional precleaning bucket group(P<0.05).Meanwhile,the number of uses of the cleaning solution(up to four times)has no significant impact on the cleaning effect(P>0.05).CONCLUSION Considering its economic cost and cleaning effect,the use of a disposable endoscope bedside precleaning kit can be an optimal option in the precleaning stage with the cleaning solution being replaced several times in the manual cleaning stage.展开更多
Isothermal hot compression tests of as-cast high-Cr ultra-super-critical(USC) rotor steel with columnar grains perpendicular to the compression direction were carried out in the temperature range from 950 to 1250°...Isothermal hot compression tests of as-cast high-Cr ultra-super-critical(USC) rotor steel with columnar grains perpendicular to the compression direction were carried out in the temperature range from 950 to 1250°C at strain rates ranging from 0.001 to 1 s^(-1). The softening mechanism was dynamic recovery(DRV) at 950°C and the strain rate of 1 s^(-1), whereas it was dynamic recrystallization(DRX) under the other conditions. A modified constitutive equation based on the Arrhenius model with strain compensation reasonably predicted the flow stress under various deformation conditions, and the activation energy was calculated to be 643.92 kJ ×mol^(-1). The critical stresses of dynamic recrystallization under different conditions were determined from the work-hardening rate(θ)–flow stress(σ) and-θ/σ–σ curves. The optimum processing parameters via analysis of the processing map and the softening mechanism were determined to be a deformation temperature range from 1100 to 1200°C and a strain-rate range from 0.001 to 0.08 s^(-1), with a power dissipation efficiency η greater than 31%.展开更多
Supersonic model combustors using two-stage injections of supercritical kerosene were experimentally investigated in both Mach 2.5 and 3.0 model combustors with stagnation temperatures of approximately 1,750 K.Supercr...Supersonic model combustors using two-stage injections of supercritical kerosene were experimentally investigated in both Mach 2.5 and 3.0 model combustors with stagnation temperatures of approximately 1,750 K.Supercritical kerosene of approximately 760 K was prepared and injected in the overall equivalence ratio range of 0.5-1.46.Two pairs of integrated injector/flameholder cavity modules in tandem were used to facilitate fuel-air mixing and stable combustion.For single-stage fuel injection at an upstream location,it was found that the boundary layer separation could propagate into the isolator with increasing fuel equivalence ratio due to excessive local heat release,which in turns changed the entry airflow conditions.Moving the fuel injection to a further downstream location could alleviate the problem,while it would result in a decrease in combustion efficiency due to shorter fuel residence time.With two-stage fuel injections the overall combustor performance was shown to be improved and kerosene injections at fuel rich conditions could be reached without the upstream propagation of the boundary layer separation into the isolator.Furthermore,effects of the entry Mach number and pilot hydrogen on combustion performance were also studied.展开更多
The influence of cooling rate and Fe-containing phases on Sr-modification of Si phases in hypoeutectic Al-Si alloys, a problem with great industrial importance, was investigated. The microstructures of samples were ex...The influence of cooling rate and Fe-containing phases on Sr-modification of Si phases in hypoeutectic Al-Si alloys, a problem with great industrial importance, was investigated. The microstructures of samples were examined using scanning electron microscopy(SEM) with energy-dispersive X-ray spectroscopy(EDX). A new method of electron probe microanalysis(EPMA) map scanning was used to analyze the Sr distribution, which gave quantitative results covering more Si particles. EPMA map scanning, together with SEM with EDX, was also used in analyzing the distribution of Fe phases. Results show that Fe-containing phase was related to the unmodified Si particles in samples with partial modification failure and the plate-like Si phases in samples without modification failure. Such a relationship was further confirmed by the microstructure observation.In conclusion, a partial failure of Sr-modification can be caused by both slow cooling rate and Fe-containing phases.展开更多
Background: Hyperglycemia is always seen amongst acute intra-cerebral hemorrhage (ICH) and usually has been reported in literature and studied in relation to mortality and poor recovery. However, literature specific t...Background: Hyperglycemia is always seen amongst acute intra-cerebral hemorrhage (ICH) and usually has been reported in literature and studied in relation to mortality and poor recovery. However, literature specific to stroke-associated pneumonia (SAP) on this topic is very small. Further, how to differentiate the predictive value of hyperglycemia with and without abnormal HbA1C in such patients is still a matter of debate and no universal consensus. We evaluated hyperglycemia as a marker for SAP in patients with ICH to assess its usefulness as a potential predictor. Materials and methods: Clinical characteristics for a sample of 551 patients with acute ICH were collected from the Beijing Tiantan Hospital of Capital Medical University, Beijing, China. Possible associated risk factors of SAP were reviewed. Hyperglycemia and HbA1C on admission were the main hypothetic predictor, SAP occurring within the first 7 days is the primary outcome. Results: The cohort study includes 551 hospitalized patients. The prevalence of hyperglycemia was 52.5% and SAP occurred in 147 (26.7%). The incidence of SAP was higher in the group with hyperglycemia than those without hyperglycemia (37.7% versus 14.5%, p 6.5) (OR, 1.57;95%CI, 0.81 - 3.23) had not been shown to be associated with SAP. Conclusions: In this hospital-based cohort of patients presenting with acute intra-hemorrhage, hyperglycemia on admission was associated significantly with SAP. The association was stronger for hyperglycemia with normal HgbA1C than for hyperglycemia with high HgbA1C. Hyperglycemia with normal HgbA1C might be a more sensitive predictor of early acute complication, such as SAP.展开更多
In this paper, compressible flow of aviation kerosene at supercritical conditions has been studied both numerically and experimentally. The thermophysical properties of supercritical kerosene are calculated using a 10...In this paper, compressible flow of aviation kerosene at supercritical conditions has been studied both numerically and experimentally. The thermophysical properties of supercritical kerosene are calculated using a 10 species surrogate based on the principle of extended corresponding states (ECS). Isentropic acceleration of supercritical kerosene to subsonic and supersonic speeds has been analyzed numerically. It has been found that the isentropic relationships of supercritical kerosene are significantly different from those of ideal gases. A two-stage fuel heating and delivery system is used to heat the kerosene up to a temperature of 820 K and pressure of 5.5 MPa with a maximum mass flow rate of 100 g/s. The characteristics of supercritical kerosene flows in a converging-diverging nozzle (Laval nozzle) have been studied experimentally. The results show that stable supersonic flows of kerosene could be established in the temperature range of 730 K-820 K and the measurements in the wall pressure agree with the numerical calculation.展开更多
Pain is a common experience for inpatients,and intensive care unit(ICU)patients undergo more pain than other departmental patients,with an incidence of 50%at rest and up to 80%during common care procedures.At present,...Pain is a common experience for inpatients,and intensive care unit(ICU)patients undergo more pain than other departmental patients,with an incidence of 50%at rest and up to 80%during common care procedures.At present,the management of persistent pain in ICU patients has attracted considerable attention,and there are many related clinical studies and guidelines.However,the management of transient pain caused by certain ICU procedures has not received sufficient attention.We reviewed the different management strategies for procedural pain in the ICU and reached a conclusion.Pain management is a process of continuous quality improvement that requires multidisciplinary team cooperation,painrelated training of all relevant personnel,effective relief of all kinds of pain,and improvement of patients'quality of life.In clinical work,which involves complex and diverse patients,we should pay attention to the following points for procedural pain:(1)Consider not only the patient's persistent pain but also his or her procedural pain;(2)Conduct multimodal pain management;(3)Provide combined sedation on the basis of pain management;and(4)Perform individualized pain management.Until now,the pain management of procedural pain in the ICU has not attracted extensive attention.Therefore,we expect additional studies to solve the existing problems of procedural pain management in the ICU.展开更多
1.Objective Because of the characteristics of multistage mineralization,long duration,relatively new age,and complicated occurrence of ore minerals,dating of sandstone-type uranium deposits has been a challenging prob...1.Objective Because of the characteristics of multistage mineralization,long duration,relatively new age,and complicated occurrence of ore minerals,dating of sandstone-type uranium deposits has been a challenging problem.For a long time,the whole-rock U-Pb isochronal method has been used in the dating of sandstone-type uranium deposits,but its accuracy has been questioned by experts.展开更多
As one of the most popular used high-speed steels, M2 possesses excellent hardness and toughness as cutting tools. Networks of eutectic carbides distributing in the inter-dendritic region are academically considered t...As one of the most popular used high-speed steels, M2 possesses excellent hardness and toughness as cutting tools. Networks of eutectic carbides distributing in the inter-dendritic region are academically considered to be the typical microstructure of M2, which can be refined by increasing cooling rate. In this paper, a novel casting method named fusible metal mold(FMM) is employed to refine the microstructure of M2 high-speed steel. Results show that FMM casting method can improve cooling rate by 100% without any contamination of the melts' composition.展开更多
A nanoscale Fe_(56.5)Mn_(11)Cr_(8.5)Ni_4Si_(10)C_(10) metallic glass was irradiated by electron beam in a 200 kV transmission electron microscope.Structure evolution in the metallic glass was investigated in situ duri...A nanoscale Fe_(56.5)Mn_(11)Cr_(8.5)Ni_4Si_(10)C_(10) metallic glass was irradiated by electron beam in a 200 kV transmission electron microscope.Structure evolution in the metallic glass was investigated in situ during continuous irradiation,where phase separation was observed after irradiation for 5 min and crystallization was observed after 33.5 min.Based on the analysis of irradiation effect,atomic displacement is believed to be the main reason for the structure rearrangement.Accumulation of atomic displacement increases the energy of the sample and promotes atomic diffusion during transformation.On the other hand,the large specific surface area of the sample also contributes to increasing free energy and atomic diffusion.展开更多
The growth behavior of Al_3Ni intermetallic compounds(IMCs)during the directional solidification of Al-10 wt%Ni alloy was investigated by synchrotron radiography.Two main growth patterns of primary Al_3Ni phase,I-like...The growth behavior of Al_3Ni intermetallic compounds(IMCs)during the directional solidification of Al-10 wt%Ni alloy was investigated by synchrotron radiography.Two main growth patterns of primary Al_3Ni phase,I-like and V-like,appeared during solidification,and I-like Al_3Ni phase grew faster than V-like phase,which can be explained by the minimum energy criterion.The growth of I-like phase can be divided into two stages and was mainly affected by undercooling and Ni concentration.We also found that V-like Al_3Ni phase can evolve into M-like phase during solidification.展开更多
基金the Hubei Provincial Natural Science Foundation(No.2018CFC847)the Hubei Cancer Hospital Foundation(No.2015C11).
文摘The aim of the present study was to explore the effects of annexin A1(ANXA1) mimetic peptide AC2-26 on sepsis-induced cardiomyocyte apoptosis in vivo and in vitro and the underlying mechanisms.In the in vivo study,a rat septic model was established by the cecal ligation and puncture (CLP).The rats were divided into control group,sepsis group and AC2-26 group.The rats in the AC2-26 group were intraperitoneally injected with AC2-26(1mg/kg)2h before CLP,and those in the control group and sepsis group were injected with the same volume of normal saline.The myocardial tissue was examined by hematoxylin and eosin (HE)staining and transmission electron microscopy (TEM).Furthermore,myocardial apoptosis was measured by terminal dUTP nick end-labeling (TUNEL)assay.In the in vitro study,H9C2cells were cultured and divided into three groups:control group,in which cells were only given the basic culture medium;LPS group,in which cells were treated with 10μg/mL LPS;AC2-26 group,in which cells were treated with 0.5μmol/L AC2-262h before 10μg/mL LPS was given.The apoptosis of H9C2 cells was detected by flow cytometry.The levels of lipoxin A4 receptor (LXA4),phosphoinositide3-kinase (PI3K)and protein kinase B (PKB or AKT)protein were measured by Western blotting, the activity of NF-KB and the level of TNF-α by ELISA and the activities of caspase-3/8by using the caspase activity kits.The in vivo study showed that the myocardial pathological damage and myocardial ultrastructural damage were significantly alleviated and the myocardial apoptosis significantly decreased in the AC2-26 group as compared with the sepsis group (P<0.05 for all). The in vivo study revealed that the apoptosis of H9C2 cells was profoundly ameliorated in the AC2-26 group relative to the sepsis group (P<0.05).The protein expression levels of LXA4 were significantly up-regulated,and those of PI3K and AKT prominently down-regulated in the AC2-26 group when compared with those in the LPS group (P<0.05 for all).The activity of NF-κB was greatly inhibited and the level of TNF-α markedly decreased in the AC2-26 group as compared with those in the LPS group (P<0.05 for all).AC2-26 treatment also significantly suppressed the activities of caspase-3/8 in H9C2 cells.In conclusion,these findings suggest that AC2-26 may alleviate the sepsis-induced cardiomyocyte apoptosis in vivo and in vivo through the LXA4/PI3K/ AKT signaling pathway.
基金financially supported by the International Science&Technology Cooperation Program of China(No.2015DFR50470)Guangdong Provincial Science&Technology Foundation(No.2015B090926013)
文摘A novel flux charging method and a crucible quenching method were employed to study the mechanism of solid fluxes refining method regarding the removal of oxide inclusions(Al_2O_3) from molten aluminum. Electrochemical polishing method was adopted to prepare surfaces of the samples. Through experiments, the morphology of the residual solidified flux in the solidified samples as well as the wetting action of the molten flux during refining were observed for the first time. Three wetting regimes denoted by absorbing regime, engulfing regime and penetration regime correlating with the removal of oxide films(the most typical and common oxide inclusions in molten aluminum) were proposed in terms of different types and distributions of oxide films and different size ratios of the molten flux to oxide films. Particularly, from a thermodynamic point of view, for the first time, the penetration regime provided concrete evidence that the practical oxide inclusions can be wet by molten flux under ambient fluid of molten aluminum. A spreading model was proposed, according to which ingredients and size parameters of practical solid fluxes can be optimized.
基金supported by the National Natural Science Foundation of China,No.31670832,31470807,31270872a grant from the National Key Research and Development Program of China,No.2016YFA0500301a grant from the State Key Laboratory of Protein and Plant Gene Research,College of Life Sciences,Peking University,China
文摘Previous studies have shown that sirtuin 1(SIRT1) reduces the production of neuronal amyloid beta(Aβ) and inhibits the inflammatory response of glial cells, thereby generating a neuroprotective effect against Aβ neurotoxicity in animal models of Alzheimer's disease. However, the protective effect of SIRT1 on astrocytes is still under investigation. This study established a time point model for the clearance of Aβ in primary astrocytes. Results showed that 12 hours of culture was sufficient for endocytosis of oligomeric Aβ, and 36 hours sufficient for effective degradation. Immunofluorescence demonstrated that Aβ degradation in primary astrocytes relies on lysosome function. Enzymatic agonists or SIRT1 inhibitors were used to stimulate cells over a concentration gradient. Aβ was co-cultured for 36 hours in medium. Western blot assay results under different conditions revealed that SIRT1 relies on its deacetylase activity to promote intracellular Aβ degradation. The experiment further screened SIRT1 using quantitative proteomics to investigate downstream, differentially expressed proteins in the Aβ degradation pathway and selected the ones related to enzyme activity of SIRT1. Most of the differentially expressed proteins detected are close to the primary astrocyte lysosomal pathway. Immunofluorescence staining demonstrated that SIRT1 relies on its deacetylase activity to upregulate lysosome number in primary astrocytes. Taken together, these findings confirm that SIRT1 relies on its deacetylase activity to upregulate lysosome number, thereby facilitating oligomeric Aβ degradation in primary astrocytes.
基金financially supported by the National Basic Research Program of China (No. 2011CB012900)
文摘The effect of solidification cooling rate on the size and distribution of inclusions in 12%Cr stainless steel was investigated. A wide range of solidification cooling rates(from 0.05 to 106 K·s-1) was achieved using various solidification processes, including conventional casting, laser remelting, and melt spinning. The size and distribution of inclusions in the steel were observed and statistically collected. For comparison, mathematical models were used to calculate the sizes of inclusions at different solidification cooling rates. Both the statistical size determined from observations and that predicted from calculations tended to decrease with increasing cooling rate; however, the experimental and calculated results did not agree well with each other at excessively high or low cooling rate. The reasons for this discrepancy were theoretically analyzed. For the size distribution of inclusions, the effect of cooling rate on the number densities of large-sized(> 2 μm) inclusions and small-sized(≤ 2 μm) inclusions were distinct. The number density of inclusions larger than 1 μm was not affected when the cooing rate was less than or equal to 6 K·s-1 because inclusion precipitation was suppressed by the increased cooling rate.
基金supported by National Key Clinical Specialty Construction Project(General Surgery).
文摘Donor-derived infection(DDI)associated with Scedosporium spp is extremely rare,and results in a very poor prognosis.The present study reports a probable DDI due to Scedosporium boydii(S.boydii)from a donor with neuropsychiatric systemic lupus erythematosus.Two recipients developed Scedosporiosis after kidney transplantation from the same donor.Recipient 1 died of central nervous system infection due to S.boydii based on the clinical presentations,and the positive metagenomic next-generation sequencing(mNGS)and culture results for the cerebrospinal fluid.The other recipient with urinary tract obstruction due to S.boydii,which was identified through the positive culture and mNGS results of the removed stents,was successfully treated by stent replacement and voriconazole administration.Undiagnosed disseminated donor infection and the transmission of S.boydii should be given attention,particularly when the donor and recipients have primary immunodeficiency disease.The screening of donors and recipients for S.boydii using mNGS may be helpful in guiding antifungal prophylaxis and treatment recipients,due to its higher sensitivity and shorter diagnostic time relative to other traditional techniques.
文摘BACKGROUND Precleaning is a key step in endoscopic reprocessing.AIM To develop an effective and economic endoscope cleaning method by using a disposable endoscope bedside precleaning kit.METHODS Altogether,228 used gastrointestinal endoscopes were selected from five high-volume endoscopy units and precleaned by a traditional precleaning bucket(group T)or a disposable endoscope bedside precleaning kit(group D).Each group was further subdivided based on the replacement frequency of the cleaning solution,which was replaced every time in subgroups T1 and D1 and every several times in subgroups Ts and Ds.The adenosine triphosphate(ATP)level and residual proteins were measured three times:Before and after precleaning and after manual cleaning.RESULTS After precleaning,the precleaning kit significantly reduced the ATP levels(P=0.034)and has a more stable ATP clearance rate than the traditional precleaning bucket.The precleaning kit also saved a quarter of the cost of enzymatic detergent used during the precleaning process.After manual cleaning,the ATP levels were also significantly lower in the precleaning kit group than in the traditional precleaning bucket group(P<0.05).Meanwhile,the number of uses of the cleaning solution(up to four times)has no significant impact on the cleaning effect(P>0.05).CONCLUSION Considering its economic cost and cleaning effect,the use of a disposable endoscope bedside precleaning kit can be an optimal option in the precleaning stage with the cleaning solution being replaced several times in the manual cleaning stage.
基金supported by the Major State Basic Research Development Program of China (No.2011CB012900)the National Natural Science Foundation of China (No.51374144)the Shanghai Rising-Star Program (No.14QA1402300)
文摘Isothermal hot compression tests of as-cast high-Cr ultra-super-critical(USC) rotor steel with columnar grains perpendicular to the compression direction were carried out in the temperature range from 950 to 1250°C at strain rates ranging from 0.001 to 1 s^(-1). The softening mechanism was dynamic recovery(DRV) at 950°C and the strain rate of 1 s^(-1), whereas it was dynamic recrystallization(DRX) under the other conditions. A modified constitutive equation based on the Arrhenius model with strain compensation reasonably predicted the flow stress under various deformation conditions, and the activation energy was calculated to be 643.92 kJ ×mol^(-1). The critical stresses of dynamic recrystallization under different conditions were determined from the work-hardening rate(θ)–flow stress(σ) and-θ/σ–σ curves. The optimum processing parameters via analysis of the processing map and the softening mechanism were determined to be a deformation temperature range from 1100 to 1200°C and a strain-rate range from 0.001 to 0.08 s^(-1), with a power dissipation efficiency η greater than 31%.
基金supported by the National Natural Science Foundation of China (10672169, 10621202)
文摘Supersonic model combustors using two-stage injections of supercritical kerosene were experimentally investigated in both Mach 2.5 and 3.0 model combustors with stagnation temperatures of approximately 1,750 K.Supercritical kerosene of approximately 760 K was prepared and injected in the overall equivalence ratio range of 0.5-1.46.Two pairs of integrated injector/flameholder cavity modules in tandem were used to facilitate fuel-air mixing and stable combustion.For single-stage fuel injection at an upstream location,it was found that the boundary layer separation could propagate into the isolator with increasing fuel equivalence ratio due to excessive local heat release,which in turns changed the entry airflow conditions.Moving the fuel injection to a further downstream location could alleviate the problem,while it would result in a decrease in combustion efficiency due to shorter fuel residence time.With two-stage fuel injections the overall combustor performance was shown to be improved and kerosene injections at fuel rich conditions could be reached without the upstream propagation of the boundary layer separation into the isolator.Furthermore,effects of the entry Mach number and pilot hydrogen on combustion performance were also studied.
基金supported by the International Science & Technology Cooperation Program of China(No.2015DFR50470)
文摘The influence of cooling rate and Fe-containing phases on Sr-modification of Si phases in hypoeutectic Al-Si alloys, a problem with great industrial importance, was investigated. The microstructures of samples were examined using scanning electron microscopy(SEM) with energy-dispersive X-ray spectroscopy(EDX). A new method of electron probe microanalysis(EPMA) map scanning was used to analyze the Sr distribution, which gave quantitative results covering more Si particles. EPMA map scanning, together with SEM with EDX, was also used in analyzing the distribution of Fe phases. Results show that Fe-containing phase was related to the unmodified Si particles in samples with partial modification failure and the plate-like Si phases in samples without modification failure. Such a relationship was further confirmed by the microstructure observation.In conclusion, a partial failure of Sr-modification can be caused by both slow cooling rate and Fe-containing phases.
文摘Background: Hyperglycemia is always seen amongst acute intra-cerebral hemorrhage (ICH) and usually has been reported in literature and studied in relation to mortality and poor recovery. However, literature specific to stroke-associated pneumonia (SAP) on this topic is very small. Further, how to differentiate the predictive value of hyperglycemia with and without abnormal HbA1C in such patients is still a matter of debate and no universal consensus. We evaluated hyperglycemia as a marker for SAP in patients with ICH to assess its usefulness as a potential predictor. Materials and methods: Clinical characteristics for a sample of 551 patients with acute ICH were collected from the Beijing Tiantan Hospital of Capital Medical University, Beijing, China. Possible associated risk factors of SAP were reviewed. Hyperglycemia and HbA1C on admission were the main hypothetic predictor, SAP occurring within the first 7 days is the primary outcome. Results: The cohort study includes 551 hospitalized patients. The prevalence of hyperglycemia was 52.5% and SAP occurred in 147 (26.7%). The incidence of SAP was higher in the group with hyperglycemia than those without hyperglycemia (37.7% versus 14.5%, p 6.5) (OR, 1.57;95%CI, 0.81 - 3.23) had not been shown to be associated with SAP. Conclusions: In this hospital-based cohort of patients presenting with acute intra-hemorrhage, hyperglycemia on admission was associated significantly with SAP. The association was stronger for hyperglycemia with normal HgbA1C than for hyperglycemia with high HgbA1C. Hyperglycemia with normal HgbA1C might be a more sensitive predictor of early acute complication, such as SAP.
基金supported by the National Natural Science Foundation of China (10672169 and 10902115)
文摘In this paper, compressible flow of aviation kerosene at supercritical conditions has been studied both numerically and experimentally. The thermophysical properties of supercritical kerosene are calculated using a 10 species surrogate based on the principle of extended corresponding states (ECS). Isentropic acceleration of supercritical kerosene to subsonic and supersonic speeds has been analyzed numerically. It has been found that the isentropic relationships of supercritical kerosene are significantly different from those of ideal gases. A two-stage fuel heating and delivery system is used to heat the kerosene up to a temperature of 820 K and pressure of 5.5 MPa with a maximum mass flow rate of 100 g/s. The characteristics of supercritical kerosene flows in a converging-diverging nozzle (Laval nozzle) have been studied experimentally. The results show that stable supersonic flows of kerosene could be established in the temperature range of 730 K-820 K and the measurements in the wall pressure agree with the numerical calculation.
文摘Pain is a common experience for inpatients,and intensive care unit(ICU)patients undergo more pain than other departmental patients,with an incidence of 50%at rest and up to 80%during common care procedures.At present,the management of persistent pain in ICU patients has attracted considerable attention,and there are many related clinical studies and guidelines.However,the management of transient pain caused by certain ICU procedures has not received sufficient attention.We reviewed the different management strategies for procedural pain in the ICU and reached a conclusion.Pain management is a process of continuous quality improvement that requires multidisciplinary team cooperation,painrelated training of all relevant personnel,effective relief of all kinds of pain,and improvement of patients'quality of life.In clinical work,which involves complex and diverse patients,we should pay attention to the following points for procedural pain:(1)Consider not only the patient's persistent pain but also his or her procedural pain;(2)Conduct multimodal pain management;(3)Provide combined sedation on the basis of pain management;and(4)Perform individualized pain management.Until now,the pain management of procedural pain in the ICU has not attracted extensive attention.Therefore,we expect additional studies to solve the existing problems of procedural pain management in the ICU.
基金This study is supported by the National Key Research and Development Project(2018YFC0604200)the International Geoscience Programme(IGCP 675)the project of Geological Survey China(DD20190119).
文摘1.Objective Because of the characteristics of multistage mineralization,long duration,relatively new age,and complicated occurrence of ore minerals,dating of sandstone-type uranium deposits has been a challenging problem.For a long time,the whole-rock U-Pb isochronal method has been used in the dating of sandstone-type uranium deposits,but its accuracy has been questioned by experts.
基金financially supported by National Basic Research Program of China(No.2011CB12900)National Natural Science Foundation of China(No.51204106)
文摘As one of the most popular used high-speed steels, M2 possesses excellent hardness and toughness as cutting tools. Networks of eutectic carbides distributing in the inter-dendritic region are academically considered to be the typical microstructure of M2, which can be refined by increasing cooling rate. In this paper, a novel casting method named fusible metal mold(FMM) is employed to refine the microstructure of M2 high-speed steel. Results show that FMM casting method can improve cooling rate by 100% without any contamination of the melts' composition.
基金financially supported by the National Natural Science Foundation of China(No.51271119)Doctoral Program of Higher Education of China(No. 20110073110005)
文摘A nanoscale Fe_(56.5)Mn_(11)Cr_(8.5)Ni_4Si_(10)C_(10) metallic glass was irradiated by electron beam in a 200 kV transmission electron microscope.Structure evolution in the metallic glass was investigated in situ during continuous irradiation,where phase separation was observed after irradiation for 5 min and crystallization was observed after 33.5 min.Based on the analysis of irradiation effect,atomic displacement is believed to be the main reason for the structure rearrangement.Accumulation of atomic displacement increases the energy of the sample and promotes atomic diffusion during transformation.On the other hand,the large specific surface area of the sample also contributes to increasing free energy and atomic diffusion.
基金supported by the National Natural Science Foundation of China (No. 51374144)Shanghai Municipal Natural Science Foundation (No. 13ZR1420600)Shanghai RisingStar Program (No. 14QA1402300)
文摘The growth behavior of Al_3Ni intermetallic compounds(IMCs)during the directional solidification of Al-10 wt%Ni alloy was investigated by synchrotron radiography.Two main growth patterns of primary Al_3Ni phase,I-like and V-like,appeared during solidification,and I-like Al_3Ni phase grew faster than V-like phase,which can be explained by the minimum energy criterion.The growth of I-like phase can be divided into two stages and was mainly affected by undercooling and Ni concentration.We also found that V-like Al_3Ni phase can evolve into M-like phase during solidification.
