A new 4-node quadrilateral flat shell element is developed for geometrically nonlinear analyses of thin and moderately thick laminated shell structures. The fiat shell element is constructed by combining a quadrilater...A new 4-node quadrilateral flat shell element is developed for geometrically nonlinear analyses of thin and moderately thick laminated shell structures. The fiat shell element is constructed by combining a quadrilateral area co- ordinate method （QAC） based membrane element AGQ6- II, and a Timoshenko beam function （TBF） method based shear deformable plate bending element ARS-Q12. In order to model folded plates and connect with beam elements, the drilling stiffness is added to the element stiffness matrix based on the mixed variational principle. The transverse shear rigidity matrix, based on the first-order shear deformation theory （FSDT）, for the laminated composite plate is evaluated using the transverse equilibrium conditions, while the shear correction factors are not needed. The conventional TBF methods are also modified to efficiently calculate the element stiffness for laminate. The new shell element is extended to large deflection and post-buckling analyses of isotropic and laminated composite shells based on the element independent corotational formulation. Numerical re- sults show that the present shell element has an excellent numerical performance for the test examples, and is applicable to stiffened plates.展开更多
Five types of tensile tests were conducted to study the yield .behavior of 2A12-T4 aluminum alloy. Parallel finite element models were built for each test and solved with ABAQUS with different yield criterions. The re...Five types of tensile tests were conducted to study the yield .behavior of 2A12-T4 aluminum alloy. Parallel finite element models were built for each test and solved with ABAQUS with different yield criterions. The result shows that any of the four criterions： von Mises yield criterion, Tresca criterion, Twin-Shear criterion and yon Mises criterion with hydrostatic pressure correction, overestimates the yield strengths of the specimens. Rather than hydrostatic pressure, Lode stress parameter is the key factor that affects the differences between experimental and simulation results. Based on this concept, a new yield model with Lode dependence modified from yon Mises criterion is postulated. Although one more parameter needs to be confirmed, the simulation results of this yield model are better than those of other criterions.展开更多
[Objectives] To establish a method for the determination of tannin in Sanguisorba officinalis L.,and provide guarantee for further control over quality of semi-finished tannin products from Sanguisorba officinalis L. ...[Objectives] To establish a method for the determination of tannin in Sanguisorba officinalis L.,and provide guarantee for further control over quality of semi-finished tannin products from Sanguisorba officinalis L. [Methods] With gallic acid as reference substance,the UV method was used to determine the content of tannin in Sanguisorba officinalis L.,and the methodological examination was done. [Results]With gallic acid as standard,when the concentration of tannin in Sanguisorba officinalis L. was 1. 02-10. 14 μg·m L^(-1),there was a good linear relationship with absorbance,the precision,reproducibility and recovery were in line with the requirements,and the absorbance value was stable within 40 min after coloration. [Conclusions] The method was simple,rapid and accurate in determining the content of tannin in Sanguisorba officinalis L.展开更多
The increasing power density of IT electronics and the enormous energy consumption of data centers lead to the urgent demand for efficient cooling technology.Due to its efficiency and safety,liquid-cooled heat sink te...The increasing power density of IT electronics and the enormous energy consumption of data centers lead to the urgent demand for efficient cooling technology.Due to its efficiency and safety,liquid-cooled heat sink technology may gradually replace air-cooled technology over time.With the ambient or higher water supply temperature,the liquid-cooled technology shortens the operating time of the chiller and improves its coefficient of performance,while the pump power consumption may increase for satisfying the constant cooling capacity.Therefore,it is significant to study the optimal water supply temperature to achieve energy-efficient operation of data centers.A virtual 30.1 kW data center is considered as the case,the liquid-cooled system is constructed with a combination of innovative manifold microchannel heat sink with oblique fins and indirect evaporative cooling technology to minimize energy consumption.A hybrid thermal management model integrating the heat dissipation model and the power consumption model is established by TRNSYS and FLUENT software.To the highest chip-safe operating temperature premise,the energy performance is analyzed under various water supply temperatures in Guangzhou.The result shows that only 21.5-hour mechanical cooling is needed with the 30℃server inlet temperature throughout the year.And the minimized power consumption occurs with the constant 29℃server inlet temperature.Moreover,the temperature adaptive control strategy(TACS)is adopted to test the cooling system power consumption under different regulation frequencies,and the by-week TACS can achieve another 11.5%energy saving than the minimum power consumption of the constant temperature control strategy.展开更多
The compressive stress-strain relationships of 6061A1 alloy over wide temperatures and strain rates are investigated. The dynamic impact experiments are performed using an im- proved high temperature split Hopkinson p...The compressive stress-strain relationships of 6061A1 alloy over wide temperatures and strain rates are investigated. The dynamic impact experiments are performed using an im- proved high temperature split Hopkinson pressure bar apparatus. The experimental results are compared with those obtained by the modified Johnson-Cook constitutive model. It is found that the dynamic mechanical behavior depends sensitively on temperature under relatively low strain rates or on strain rate at relatively high temperatures. The good agreement indicates that it is valid to adopt the parameter identification method and the constitutive model to describe and predict the mechanical response of materials.展开更多
A diffusive gradients in thin films （DGT） technique based on hydrous zirconium oxide （Zr-oxide） has been recently developed for the measurement of dissolved reactive phosphate （DRP）. In this study, the detailed ...A diffusive gradients in thin films （DGT） technique based on hydrous zirconium oxide （Zr-oxide） has been recently developed for the measurement of dissolved reactive phosphate （DRP）. In this study, the detailed performance of the DGT technique is reported. Spiking experiments revealed that several orthophosphate monoester compounds contributed to the Zr-oxide DGT measurements of DRP. However, such a phenomenon is unlikely to occur during field conditions due to the low concentration of organic P in typical natural waters. The presence of Cl- （up to 106 g/L）, SO42- （up to 16 g/L）, HCO3- （up to 817 g/L）, and AsO2- and AsO 3 4 （both up to 1 mg As/L） in solutions had negligible effects on the measurement of DRP. The threshold concentrations of Cl-, SO42- and HCO3- have been increased from previous reports for the measurements of DRP using other adsorbent-based DGT techniques. The capacity for DGT measurements of DRP decreased with increasing solution pH （4.2-9.2）. The lowest capacity （95 μg P/m2 at pH 9.2） was still greater than that of other DGT techniques that are usually used for the measurement of DRP （2-12 μg P/cm2 ）. The Zr-oxide binding gel could be stored for up to 2 years without any aging effect. This period of validity was considerably longer than the ferrihydrite binding gel that is commonly used in present DGT devices （6 months）. The field application revealed that the concentrations of DRP measured in three fresh water samples using the Zr-oxide DGT technique were in agreement with those of the traditional colorimetric method.展开更多
Background:Conventional pressure support ventilation(PSP)is triggered and cycled off by pneumatic signals such as flow.Patient-ventilator asynchrony is common during pressure support ventilation,thereby contributing t...Background:Conventional pressure support ventilation(PSP)is triggered and cycled off by pneumatic signals such as flow.Patient-ventilator asynchrony is common during pressure support ventilation,thereby contributing to an increased inspiratory effort.Using diaphragm electrical activity,neurally controlled pressure support(PSN)could hypothetically eliminate the asynchrony and reduce inspiratory effort.The purpose of this study was to compare the differences between PSN and PSP in terms of patient-ventilator synchrony,inspiratory effort,and breathing pattern.Methods:Eight post-operative patients without respiratory system comorbidity,eight patients with acute respiratory distress syndrome(ARDS)and obvious restrictive acute respiratory failure(ARF),and eight patients with chronic obstructive pulmonary disease(COPD)and mixed restrictive and obstructive ARF were enrolled.Patient-ventilator interactions were analyzed with macro asynchronies(ineffective,double,and auto triggering),micro asynchronies(inspiratory trigger delay,premature,and late cycling),and the total asynchrony index(AI).Inspiratory efforts for triggering and total inspiration were analyzed.Results:Total AI of PSN was consistently lower than that of PSP in COPD(3%vs.93%,P=0.012 for 100%support level;8%vs.104%,P=0.012 for 150%support level),ARDS(8%vs.29%,P=0.012 for 100%support level;16%vs.41%,P=0.017 for 150%support level),and post-operative patients(21%vs.35%,P=0.012 for 100%support level;15%vs.50%,P=0.017 for 150%support level).Improved support levels from 100%to 150%statistically increased total AI during PSP but not during PSN in patients with COPD or ARDS.Patients’inspiratory efforts for triggering and total inspiration were significantly lower during PSN than during PSP in patients with COPD or ARDS under both support levels(P<0.05).There was no difference in breathing patterns between PSN and PSP.Conclusions:PSN improves patient-ventilator synchrony and generates a respiratory pattern similar to PSP independently of any level of support in patients with different respiratory system mechanical properties.PSN,which reduces the trigger and total patient’s inspiratory effort in patients with COPD or ARDS,might be an alternative mode for PSP.Trial Registration:ClinicalTrials.gov,NCT01979627;https://clinicaltrials.gov/ct2/show/record/NCT01979627.展开更多
Cuticular wax is a natural barrier on terrestrial plant organs,which protects plants from damages caused by a variety of stresses.Here,we report the identification and functional characterization of a cuticular-wax-re...Cuticular wax is a natural barrier on terrestrial plant organs,which protects plants from damages caused by a variety of stresses.Here,we report the identification and functional characterization of a cuticular-wax-related gene,Zea mays L.SEMI-ROLLED LEAF 5(ZmSRL5).The loss-of-function mutant srl5,which was created by a 3,745 bp in-sertion in the first intron that led to the premature tran-script,exhibited abnormal wax crystal morphology and distribution,which,in turn,caused the pleiotropic pheno-types including increased chlorophyll leaching and water loss rate,decreased leaf temperature,sensitivity to drought,as well as semi-rolled mature leaves.However,total wax amounts showed no significant difference between wild type and semi-rolled leaf5(srl5)mutant.The phenotype of srl5 was confirmed through the generation of two allelic mutants using CRISPR/Cas9.ZmSRL5 encodes a CASPARIAN-STRIP-MEMBRANE-DOMAIN-LIKE(CASPL)protein located in plasma membrane,and highly expressed in developing leaves.Further analysis showed that the expressions of the most wax related genes were not affected or slightly al-tered in srl5.This study,thus,primarily uncovers that ZmSRL5 is required for the structure formation of the cu-ticular wax and could increase the drought tolerance by maintaining the proper cuticular wax structure in maize.展开更多
This study was to investigate the effect of annexin A5 on testosterone secretion from primary rat Leydig cells and the underlying mechanisms. Isolated rat Leydig ceils were treated with annexin A5. Testosterone produc...This study was to investigate the effect of annexin A5 on testosterone secretion from primary rat Leydig cells and the underlying mechanisms. Isolated rat Leydig ceils were treated with annexin A5. Testosterone production was detected by chemiluminescence assay. The protein and mRNA of Steroidogenic acute regulatory （STAR）, P450scc, 3β-hydroxysteroid dehydrogenase （3β-HSD）, 17β-hydroxysteroid dehydrogenase （17β-HSD）, and 17β-hydroxylase were examined by Western blotting and semi-quantitative RT-PCR, respectively. Annexin A5 significantly stimulated testosterone secretion from rat Leydig cells in dose- and time-dependent manners and increased mRNA and protein expression of STAR, P450scc, 3β-HSD, and 17β-HSD but not 17α-hydroxylase. Annexin A5 knockdown by siRNA significantly decreased the level of testosterone and protein expression of P450scc, 3β-HSD, and 17β-HSD. The significant activation of ERK1/2 signaling was observed at 5, 10, and 30 min after annexin A5 treatment. After the pretreatment of Leydig cells with ERK inhibitor PD98059 （50 μmol l^-1） for 20 min, the effects of annexin A5 on promoting testosterone secretion and increasing the expression of P450scc, 3β-HSD, and 17β-HSD were completely abrogated （P 〈 0.05）. Thus, ERK1/2 signaling is involved in the roles of annexin A5 in mediating testosterone production and the expression of P450scc, 3β-HSD, and 17β-HSD in Leydig cells.展开更多
Reasonable and effective fatigue load spectrum is key of aircraft structural fatigue test.Two kinds of load spectra simplification approaches based on statistical consistent fatigue damage model are proposed in the pa...Reasonable and effective fatigue load spectrum is key of aircraft structural fatigue test.Two kinds of load spectra simplification approaches based on statistical consistent fatigue damage model are proposed in the paper.One method is to simplify the original multi-level load spectra to spectral load with fewer level and was verified by the experimental data of five levels and seven levels load spectra.The equivalent damage here is not equivalent fatigue life,but equivalent number of spectral blocks.Moreover,it was proved that a section of low stress load cannot be converted into the highest stress load considering equivalent damage.The other is to convert the life distribution under multi-level load spectra into that of constant amplitude spectrum according to a certain principle,that is,equivalent damage is achieved through equivalent fatigue life,and two groups of three levels spectral data were used for experimental verification.The results show that equivalent damage simplification approach of multi-level load spectra is feasible,and it achieve that the damage of one loading block before and after the simplification is equal in probability statistics.The life distribution of load simplified as constant amplitude spectrum is consistent with test data.The simplification method presented in this paper can be generalized and is a predictive engineering method which does not depend on experimental data.展开更多
Background:To describe the current status of aerosol therapy during mechanical ventilation(MV)and the prac-tice,knowledge,and beliefs about aerosol therapy in physicians working in the intensive care unit(ICU)in China...Background:To describe the current status of aerosol therapy during mechanical ventilation(MV)and the prac-tice,knowledge,and beliefs about aerosol therapy in physicians working in the intensive care unit(ICU)in China.Methods:A physician self-administered questionnaire-based cross-sectional survey was carried out from January 2019 to July 2019.An electronic questionnaire was designed,and physicians who worked regularly in ICUs across several hospitals were contacted through WeChat.Answers to all questions and the general characteristics of physicians who answered the questionnaire were collected and analyzed.Results:A total of 2203 medical staffwho regularly worked in the ICUs completed this questionnaire(9.0%missing data);87.7%of the participants were doctors.Most respondents claimed that they often administered aerosolization therapy.Ultrasonic atomizer(50.7%)and jet nebulizer(48.6%)were the most commonly used atomization devices.Bronchodilators(65.8%)and steroids(66.3%)were the most frequently aerosolized drugs during MV.During nebulization,ventilator settings were never changed by 32.7%of respondents.Only 49.1%of respondents knew the appropriate place for a nebulizer.Further,62.7%of respondents using heated humidifiers reported turning them offduring nebulization.Specific knowledge about droplet size and nebulization yield was poor.Respondents from tertiary hospitals and those with higher technical title or work experience tended to have better accuracy than those from primary hospitals or with lower technical titles(P<0.050).Conclusions:Aerosol therapy was commonly used during MV,and the most frequent drugs were bronchodila-tors and steroids.Scientific knowledge about the optimal implementation of aerosol therapy during MV seemed deficient.展开更多
To the Editor: Sepsis and septic shock are a leading cause of intensive care unit (ICU) admissions and induce significant morbidity and mortality.[1,2] Early propitiate antibiotics administration is significantly asso...To the Editor: Sepsis and septic shock are a leading cause of intensive care unit (ICU) admissions and induce significant morbidity and mortality.[1,2] Early propitiate antibiotics administration is significantly associated with improved survival in sepsis and septic shock[3,4] which is recommended by the international guidelines.[5] However, the compliance to sepsis protocols remains very low.[6] Nurses, who play a vital role in carrying out physician orders, are likely associated with the compliance to empiric antibiotic administration. Phua et al[7] showed that nurses occupy an essential and conscious position as brokers of doctors’ antibiotic decisions. In addition, other studies also demonstrated that nurse-led protocols were an effective, safe, and sustainable method for achieving early antibiotic administration in patients with suspected febrile neutropenia.[8] Therefore, we performed a retrospective cohort study to confirm the effect of nursing staff capacity on the compliance of nurses to empiric antibiotic treatment in patients with septic shock.展开更多
The co-rotational finite element formulation is an attractive technique extending the capabilities of an existing high performing linear element to geometrically nonlinear analysis.This paper presents a modified co-ro...The co-rotational finite element formulation is an attractive technique extending the capabilities of an existing high performing linear element to geometrically nonlinear analysis.This paper presents a modified co-rotational framework,unified for beam,shell,and brick elements.A unified zero-spin criterion is proposed to specify the local element frame,whose origin is always located at the centroid.Utilizing this criterion,a spin matrix is introduced,and the local frame is invariant to the element nodal ordering.Additionally,the projector matrix is redefined in a more intuitive way,which is the derivative of local co-rotational element frame with respect to the global one.Furthermore,the nodal rotation is obtained with pseudo vector and instantaneous rotation,under a high-order accurate transformation.The resulting formulations are achieved in unified expression and thus a series of linear elements can be embedded into the framework.Several examples are presented to demonstrate the efficiency and accuracy of the proposed framework for large displacement analysis.展开更多
文摘A new 4-node quadrilateral flat shell element is developed for geometrically nonlinear analyses of thin and moderately thick laminated shell structures. The fiat shell element is constructed by combining a quadrilateral area co- ordinate method （QAC） based membrane element AGQ6- II, and a Timoshenko beam function （TBF） method based shear deformable plate bending element ARS-Q12. In order to model folded plates and connect with beam elements, the drilling stiffness is added to the element stiffness matrix based on the mixed variational principle. The transverse shear rigidity matrix, based on the first-order shear deformation theory （FSDT）, for the laminated composite plate is evaluated using the transverse equilibrium conditions, while the shear correction factors are not needed. The conventional TBF methods are also modified to efficiently calculate the element stiffness for laminate. The new shell element is extended to large deflection and post-buckling analyses of isotropic and laminated composite shells based on the element independent corotational formulation. Numerical re- sults show that the present shell element has an excellent numerical performance for the test examples, and is applicable to stiffened plates.
基金express their thanks to Chinese Aircraft Strength Research Institute for financial supportDynamics and Strength Laboratory of NWPU for theirhelp in the experiments
文摘Five types of tensile tests were conducted to study the yield .behavior of 2A12-T4 aluminum alloy. Parallel finite element models were built for each test and solved with ABAQUS with different yield criterions. The result shows that any of the four criterions： von Mises yield criterion, Tresca criterion, Twin-Shear criterion and yon Mises criterion with hydrostatic pressure correction, overestimates the yield strengths of the specimens. Rather than hydrostatic pressure, Lode stress parameter is the key factor that affects the differences between experimental and simulation results. Based on this concept, a new yield model with Lode dependence modified from yon Mises criterion is postulated. Although one more parameter needs to be confirmed, the simulation results of this yield model are better than those of other criterions.
文摘[Objectives] To establish a method for the determination of tannin in Sanguisorba officinalis L.,and provide guarantee for further control over quality of semi-finished tannin products from Sanguisorba officinalis L. [Methods] With gallic acid as reference substance,the UV method was used to determine the content of tannin in Sanguisorba officinalis L.,and the methodological examination was done. [Results]With gallic acid as standard,when the concentration of tannin in Sanguisorba officinalis L. was 1. 02-10. 14 μg·m L^(-1),there was a good linear relationship with absorbance,the precision,reproducibility and recovery were in line with the requirements,and the absorbance value was stable within 40 min after coloration. [Conclusions] The method was simple,rapid and accurate in determining the content of tannin in Sanguisorba officinalis L.
基金financially supported under Guangzhou Science and Technology Plan Project (No.202201010108)CAS Science and Technology Service Network Program Project (No.20211600200082)Guangzhou Development Zone International Science and Technology Cooperation Project Funding (No.2021GH07).
文摘The increasing power density of IT electronics and the enormous energy consumption of data centers lead to the urgent demand for efficient cooling technology.Due to its efficiency and safety,liquid-cooled heat sink technology may gradually replace air-cooled technology over time.With the ambient or higher water supply temperature,the liquid-cooled technology shortens the operating time of the chiller and improves its coefficient of performance,while the pump power consumption may increase for satisfying the constant cooling capacity.Therefore,it is significant to study the optimal water supply temperature to achieve energy-efficient operation of data centers.A virtual 30.1 kW data center is considered as the case,the liquid-cooled system is constructed with a combination of innovative manifold microchannel heat sink with oblique fins and indirect evaporative cooling technology to minimize energy consumption.A hybrid thermal management model integrating the heat dissipation model and the power consumption model is established by TRNSYS and FLUENT software.To the highest chip-safe operating temperature premise,the energy performance is analyzed under various water supply temperatures in Guangzhou.The result shows that only 21.5-hour mechanical cooling is needed with the 30℃server inlet temperature throughout the year.And the minimized power consumption occurs with the constant 29℃server inlet temperature.Moreover,the temperature adaptive control strategy(TACS)is adopted to test the cooling system power consumption under different regulation frequencies,and the by-week TACS can achieve another 11.5%energy saving than the minimum power consumption of the constant temperature control strategy.
基金Project supported by the State 973 Program of China (No. 2013CB03570)the National Natural Science Foundation of China (Nos. 11272259, 11002104, 10902090 and 11021202)
文摘The compressive stress-strain relationships of 6061A1 alloy over wide temperatures and strain rates are investigated. The dynamic impact experiments are performed using an im- proved high temperature split Hopkinson pressure bar apparatus. The experimental results are compared with those obtained by the modified Johnson-Cook constitutive model. It is found that the dynamic mechanical behavior depends sensitively on temperature under relatively low strain rates or on strain rate at relatively high temperatures. The good agreement indicates that it is valid to adopt the parameter identification method and the constitutive model to describe and predict the mechanical response of materials.
基金sponsored by the National Natural Scientific Foundation of China (No. 41001334, 41001325)the Project of Knowledge Innovation for the 3rd period, the Chinese Academy of Sciences (No. KZCX2-YW-JS304)the Natural Scientific Foundation of Jiangsu Province, China (No. BK2010606)
文摘A diffusive gradients in thin films （DGT） technique based on hydrous zirconium oxide （Zr-oxide） has been recently developed for the measurement of dissolved reactive phosphate （DRP）. In this study, the detailed performance of the DGT technique is reported. Spiking experiments revealed that several orthophosphate monoester compounds contributed to the Zr-oxide DGT measurements of DRP. However, such a phenomenon is unlikely to occur during field conditions due to the low concentration of organic P in typical natural waters. The presence of Cl- （up to 106 g/L）, SO42- （up to 16 g/L）, HCO3- （up to 817 g/L）, and AsO2- and AsO 3 4 （both up to 1 mg As/L） in solutions had negligible effects on the measurement of DRP. The threshold concentrations of Cl-, SO42- and HCO3- have been increased from previous reports for the measurements of DRP using other adsorbent-based DGT techniques. The capacity for DGT measurements of DRP decreased with increasing solution pH （4.2-9.2）. The lowest capacity （95 μg P/m2 at pH 9.2） was still greater than that of other DGT techniques that are usually used for the measurement of DRP （2-12 μg P/cm2 ）. The Zr-oxide binding gel could be stored for up to 2 years without any aging effect. This period of validity was considerably longer than the ferrihydrite binding gel that is commonly used in present DGT devices （6 months）. The field application revealed that the concentrations of DRP measured in three fresh water samples using the Zr-oxide DGT technique were in agreement with those of the traditional colorimetric method.
基金National Science and Technology Major Project(No.2020ZX09201015)Clinical Science and Technology Specific Projects of Jiangsu Province(Nos.BE2018743,BE2019749)+3 种基金National Natural Science Foundation of China(Nos.81870066,81670074,81930058)Natural Science Foundation of Jiangsu Province(No.BK20171271)Jiangsu Provincial Medical Youth Talent(No.QNRC 2016807)Third Level Talents of the"333 High Level Talents Training Project"in the fifth phase in Jiangsu(No.LGY2016051)。
文摘Background:Conventional pressure support ventilation(PSP)is triggered and cycled off by pneumatic signals such as flow.Patient-ventilator asynchrony is common during pressure support ventilation,thereby contributing to an increased inspiratory effort.Using diaphragm electrical activity,neurally controlled pressure support(PSN)could hypothetically eliminate the asynchrony and reduce inspiratory effort.The purpose of this study was to compare the differences between PSN and PSP in terms of patient-ventilator synchrony,inspiratory effort,and breathing pattern.Methods:Eight post-operative patients without respiratory system comorbidity,eight patients with acute respiratory distress syndrome(ARDS)and obvious restrictive acute respiratory failure(ARF),and eight patients with chronic obstructive pulmonary disease(COPD)and mixed restrictive and obstructive ARF were enrolled.Patient-ventilator interactions were analyzed with macro asynchronies(ineffective,double,and auto triggering),micro asynchronies(inspiratory trigger delay,premature,and late cycling),and the total asynchrony index(AI).Inspiratory efforts for triggering and total inspiration were analyzed.Results:Total AI of PSN was consistently lower than that of PSP in COPD(3%vs.93%,P=0.012 for 100%support level;8%vs.104%,P=0.012 for 150%support level),ARDS(8%vs.29%,P=0.012 for 100%support level;16%vs.41%,P=0.017 for 150%support level),and post-operative patients(21%vs.35%,P=0.012 for 100%support level;15%vs.50%,P=0.017 for 150%support level).Improved support levels from 100%to 150%statistically increased total AI during PSP but not during PSN in patients with COPD or ARDS.Patients’inspiratory efforts for triggering and total inspiration were significantly lower during PSN than during PSP in patients with COPD or ARDS under both support levels(P<0.05).There was no difference in breathing patterns between PSN and PSP.Conclusions:PSN improves patient-ventilator synchrony and generates a respiratory pattern similar to PSP independently of any level of support in patients with different respiratory system mechanical properties.PSN,which reduces the trigger and total patient’s inspiratory effort in patients with COPD or ARDS,might be an alternative mode for PSP.Trial Registration:ClinicalTrials.gov,NCT01979627;https://clinicaltrials.gov/ct2/show/record/NCT01979627.
基金We are grateful for the financial support for the study bythe National Key Research and Development Programof China(2016YFDo100303)National NatureScience Foundation of China(31771796 and 31860383).
文摘Cuticular wax is a natural barrier on terrestrial plant organs,which protects plants from damages caused by a variety of stresses.Here,we report the identification and functional characterization of a cuticular-wax-related gene,Zea mays L.SEMI-ROLLED LEAF 5(ZmSRL5).The loss-of-function mutant srl5,which was created by a 3,745 bp in-sertion in the first intron that led to the premature tran-script,exhibited abnormal wax crystal morphology and distribution,which,in turn,caused the pleiotropic pheno-types including increased chlorophyll leaching and water loss rate,decreased leaf temperature,sensitivity to drought,as well as semi-rolled mature leaves.However,total wax amounts showed no significant difference between wild type and semi-rolled leaf5(srl5)mutant.The phenotype of srl5 was confirmed through the generation of two allelic mutants using CRISPR/Cas9.ZmSRL5 encodes a CASPARIAN-STRIP-MEMBRANE-DOMAIN-LIKE(CASPL)protein located in plasma membrane,and highly expressed in developing leaves.Further analysis showed that the expressions of the most wax related genes were not affected or slightly al-tered in srl5.This study,thus,primarily uncovers that ZmSRL5 is required for the structure formation of the cu-ticular wax and could increase the drought tolerance by maintaining the proper cuticular wax structure in maize.
文摘This study was to investigate the effect of annexin A5 on testosterone secretion from primary rat Leydig cells and the underlying mechanisms. Isolated rat Leydig ceils were treated with annexin A5. Testosterone production was detected by chemiluminescence assay. The protein and mRNA of Steroidogenic acute regulatory （STAR）, P450scc, 3β-hydroxysteroid dehydrogenase （3β-HSD）, 17β-hydroxysteroid dehydrogenase （17β-HSD）, and 17β-hydroxylase were examined by Western blotting and semi-quantitative RT-PCR, respectively. Annexin A5 significantly stimulated testosterone secretion from rat Leydig cells in dose- and time-dependent manners and increased mRNA and protein expression of STAR, P450scc, 3β-HSD, and 17β-HSD but not 17α-hydroxylase. Annexin A5 knockdown by siRNA significantly decreased the level of testosterone and protein expression of P450scc, 3β-HSD, and 17β-HSD. The significant activation of ERK1/2 signaling was observed at 5, 10, and 30 min after annexin A5 treatment. After the pretreatment of Leydig cells with ERK inhibitor PD98059 （50 μmol l^-1） for 20 min, the effects of annexin A5 on promoting testosterone secretion and increasing the expression of P450scc, 3β-HSD, and 17β-HSD were completely abrogated （P 〈 0.05）. Thus, ERK1/2 signaling is involved in the roles of annexin A5 in mediating testosterone production and the expression of P450scc, 3β-HSD, and 17β-HSD in Leydig cells.
文摘Reasonable and effective fatigue load spectrum is key of aircraft structural fatigue test.Two kinds of load spectra simplification approaches based on statistical consistent fatigue damage model are proposed in the paper.One method is to simplify the original multi-level load spectra to spectral load with fewer level and was verified by the experimental data of five levels and seven levels load spectra.The equivalent damage here is not equivalent fatigue life,but equivalent number of spectral blocks.Moreover,it was proved that a section of low stress load cannot be converted into the highest stress load considering equivalent damage.The other is to convert the life distribution under multi-level load spectra into that of constant amplitude spectrum according to a certain principle,that is,equivalent damage is achieved through equivalent fatigue life,and two groups of three levels spectral data were used for experimental verification.The results show that equivalent damage simplification approach of multi-level load spectra is feasible,and it achieve that the damage of one loading block before and after the simplification is equal in probability statistics.The life distribution of load simplified as constant amplitude spectrum is consistent with test data.The simplification method presented in this paper can be generalized and is a predictive engineering method which does not depend on experimental data.
基金This study was supported by the National Science and Tech-nology Major Project(Grant No.2020ZX09201015)the Clinical Science and Technology Specific Projects of Jiangsu Province(Grant Nos BE2018743,BE2019749)+3 种基金the National Natural Sci-ence Foundation of China(Grant Nos.81870066,81670074,81930058)the Natural Science Foundation of Jiangsu Province(Grant No.BK20171271)the Jiangsu Provincial Medical Youth Talent(Grant No.QNRC 2016807)the Third Level Tal-ents of the“333 High Level Talents Training Project”in the fifth phase in Jiangsu(Grant No.LGY2016051).
文摘Background:To describe the current status of aerosol therapy during mechanical ventilation(MV)and the prac-tice,knowledge,and beliefs about aerosol therapy in physicians working in the intensive care unit(ICU)in China.Methods:A physician self-administered questionnaire-based cross-sectional survey was carried out from January 2019 to July 2019.An electronic questionnaire was designed,and physicians who worked regularly in ICUs across several hospitals were contacted through WeChat.Answers to all questions and the general characteristics of physicians who answered the questionnaire were collected and analyzed.Results:A total of 2203 medical staffwho regularly worked in the ICUs completed this questionnaire(9.0%missing data);87.7%of the participants were doctors.Most respondents claimed that they often administered aerosolization therapy.Ultrasonic atomizer(50.7%)and jet nebulizer(48.6%)were the most commonly used atomization devices.Bronchodilators(65.8%)and steroids(66.3%)were the most frequently aerosolized drugs during MV.During nebulization,ventilator settings were never changed by 32.7%of respondents.Only 49.1%of respondents knew the appropriate place for a nebulizer.Further,62.7%of respondents using heated humidifiers reported turning them offduring nebulization.Specific knowledge about droplet size and nebulization yield was poor.Respondents from tertiary hospitals and those with higher technical title or work experience tended to have better accuracy than those from primary hospitals or with lower technical titles(P<0.050).Conclusions:Aerosol therapy was commonly used during MV,and the most frequent drugs were bronchodila-tors and steroids.Scientific knowledge about the optimal implementation of aerosol therapy during MV seemed deficient.
基金grants from the Natural Science Foundation of Jiangsu Province (No. BK20161433)Jiangsu Provincial Key Medical Discipline (No.ZDXKA2016025)Jiangsu Provincial Medical Talent (No.ZDRCA2016082).
文摘To the Editor: Sepsis and septic shock are a leading cause of intensive care unit (ICU) admissions and induce significant morbidity and mortality.[1,2] Early propitiate antibiotics administration is significantly associated with improved survival in sepsis and septic shock[3,4] which is recommended by the international guidelines.[5] However, the compliance to sepsis protocols remains very low.[6] Nurses, who play a vital role in carrying out physician orders, are likely associated with the compliance to empiric antibiotic administration. Phua et al[7] showed that nurses occupy an essential and conscious position as brokers of doctors’ antibiotic decisions. In addition, other studies also demonstrated that nurse-led protocols were an effective, safe, and sustainable method for achieving early antibiotic administration in patients with suspected febrile neutropenia.[8] Therefore, we performed a retrospective cohort study to confirm the effect of nursing staff capacity on the compliance of nurses to empiric antibiotic treatment in patients with septic shock.
基金the National Natural Science Foundation of China(Grant Nos.11972297 and 11972300)the Fundamental Research Funds for the Central Universities of China(Grant No.G2019KY05203).
文摘The co-rotational finite element formulation is an attractive technique extending the capabilities of an existing high performing linear element to geometrically nonlinear analysis.This paper presents a modified co-rotational framework,unified for beam,shell,and brick elements.A unified zero-spin criterion is proposed to specify the local element frame,whose origin is always located at the centroid.Utilizing this criterion,a spin matrix is introduced,and the local frame is invariant to the element nodal ordering.Additionally,the projector matrix is redefined in a more intuitive way,which is the derivative of local co-rotational element frame with respect to the global one.Furthermore,the nodal rotation is obtained with pseudo vector and instantaneous rotation,under a high-order accurate transformation.The resulting formulations are achieved in unified expression and thus a series of linear elements can be embedded into the framework.Several examples are presented to demonstrate the efficiency and accuracy of the proposed framework for large displacement analysis.
