目的:探讨南阳市第一人民医院抗菌药物的使用情况及与常见的细菌耐药的相关性。方法:收集南阳市第一人民医院2018年1月至2021年12月临床患者送检的阳性标本,统计临床标本分离病原菌检出情况、常见抗菌药物消耗情况以及常见的革兰氏阴性...目的:探讨南阳市第一人民医院抗菌药物的使用情况及与常见的细菌耐药的相关性。方法:收集南阳市第一人民医院2018年1月至2021年12月临床患者送检的阳性标本,统计临床标本分离病原菌检出情况、常见抗菌药物消耗情况以及常见的革兰氏阴性杆菌、阳性球菌对抗菌药物产生的耐药率(%)与抗菌药物用药频度(Frequency of defined daily doses,DDDs)的相关性。结果:我院2018年至2021年抗菌药物DDDs较高的抗菌药物依次为美洛西林、头孢他啶、哌拉西林他唑巴坦,检出率较高的病原菌分别为大肠埃希氏菌、肺炎克雷伯菌、金黄色葡萄球菌等。大肠埃希菌产生的耐药率与哌拉西林他唑巴坦、头孢呋辛钠DDDs均有相关性(r=-0.107、0.432);肺炎克雷伯菌产生的耐药率与哌拉西林他唑巴坦、左氧氟沙星氯化钠、头孢呋辛钠DDDs呈正相关(r=0.410、0.720、0.420);铜绿假单胞菌与哌拉西林他唑巴坦、头孢哌酮舒巴坦钠DDDs呈正相关(r=0.716、0.933);金黄色葡萄球菌的耐药率与左氧氟沙星DDDs呈正相关(r=0.661);肺炎链球菌产生的耐药率与左氧氟沙星、头孢呋辛钠DDDs均存在正相关关系(r=0.416和0.482)。结论:抗菌药物的DDDs与常见细菌产生的耐药性具有一定的相关性,我院应严格控制抗菌药物的DDDs,根据感染性病种及药敏试验结果选择适当的抗菌药,加强常见病原菌的耐药监测。展开更多
Glibenclamide, a blocker of ATP-sensitive potassium channels, has been found to induce apoptosis in some cell types, including pancreatic beta-cells. Since autophagy plays doubleedged roles in pancreatic beta-cell sur...Glibenclamide, a blocker of ATP-sensitive potassium channels, has been found to induce apoptosis in some cell types, including pancreatic beta-cells. Since autophagy plays doubleedged roles in pancreatic beta-cell survival, frequently through cross-talking with apoptosis, we investigated if glibenclamide induced autophagy in INS-1 rat insulinoma cells and the influence of autophagy on apoptosis. Mammalian target of rapamycin (mTOR) is a negative regulator of autophagy. As one of the substrates of mTOR, p70 S6 kinase (p70 S6K) is phosphorylated upon mTOR activation. Our results showed that glibenclamide induced an elevated protein level of the autophagy marker LC3-II, while decreasing phosphorylated p70 S6K, indicative of inhibition on mTOR signaling in INS-1 cells. Furthermore, inhibiting glibenclamide-induced autophagy via knocking down the autophagy essential gene Atg7 decreased cell viability and increased apoptosis in INS-1 cells. Our results indicate that glibenclamide induces autophagy in INS-1 cells, and that autophagy activation is exerting a protective activity against apoptosis.展开更多
Chlorophyll a concentration(CHL)is an important proxy of the marine ecological environment and phytoplankton production.Long-term trends in CHL of the South China Sea(SCS)reflect the changes in the ecosystem’s produc...Chlorophyll a concentration(CHL)is an important proxy of the marine ecological environment and phytoplankton production.Long-term trends in CHL of the South China Sea(SCS)reflect the changes in the ecosystem’s productivity and functionality in the regional carbon cycle.In this study,we applied a previously reconstructed 15-a(2005–2019)CHL product,which has a complete coverage at 4 km and daily resolutions,to analyze the long-term trends of CHL in the SCS.Quantile regression was used to elaborate on the long-term trends of high,median,and low CHL values,as an extended method of conventional linear regression.The results showed downward trends of the SCS CHL for the 75th,50th,and 25th quantile in the past 15 a,which were−0.0040 mg/(m^(3)·a)(−1.62%per year),−0.0023 mg/(m^(3)·a)(−1.10%per year),and−0.0019 mg/(m^(3)·a)(−1.01%per year).The negative trends in winter(November to March)were more prominent than those in summer(May to September).In terms of spatial distribution,the downward trend was more significant in regions with higher CHL.These led to a reduced standard deviation of CHL over time and space.We further explored the influence of various dynamic factors on CHL trends for the entire SCS and two typical systems(winter Luzon Strait(LZ)and summer Vietnam Upwelling System(SV))with single-variate linear regression and multivariate Random Forest analysis.The multivariate analysis suggested the CHL trend pattern can be best explained by the trends of wind speed and mixed-layer depth.The divergent importance of controlling factors for LZ and SV can explain the different CHL trends for the two systems.This study expanded our understanding of the long-term changes of CHL in the SCS and provided a reference for investigating changes in the marine ecosystem.展开更多
With the help of the first principle calculation,the solid-state reaction experiment was conducted to investigate the alteration in the sintering and the microwave dielectric properties of Mg_(3)B_(2)O_(6)ceramic with...With the help of the first principle calculation,the solid-state reaction experiment was conducted to investigate the alteration in the sintering and the microwave dielectric properties of Mg_(3)B_(2)O_(6)ceramic with many Zn^(2+)substitutions.These properties were characterized using the scanning electron microscopy,network analyzer,X-ray diffraction,Raman spectroscopy,energy-dispersive spectroscopy,and thermomechanical and differential-thermal analyses.The coexistence of Mg_(3)B_(2)O_(6),Mg_(2)B_(2)O_(5)and ZnO ceramics could be observed with increasing Zn^(2+)addition,and the lattice distortion occurred in the Mg_(2)B_(2)O_(5)and Mg_(3)B_(2)O_(6)ceramics due to the substitution of Mg^(2+)with Zn^(2+).The electron density and the bond property of the MgO_(6)octahedron changed,and a quantitative method was used to discuss the variation in sintering,substitution and phase formation properties.The densification window was decreased to 1100℃,and the dielectric properties improved with the formation of a three-phase borate solid solution(dielectric constant=6.73,quality factor=112,000 GHz at 16 GHz(Q=7000),temperature coefficient of resonant frequency=-61.2 ppm℃^(-1),and relative density=97.0%).展开更多
The constant winding tension can make the filament arranged in order. The stress distribution between the filament balance fully gives play to the enhancement of filament, and increases the intensive workload of the c...The constant winding tension can make the filament arranged in order. The stress distribution between the filament balance fully gives play to the enhancement of filament, and increases the intensive workload of the composite winding material. This paper conducts the mechanical analysis for the unwinding roller and tension measuring roller of the cylindrical winding machine so that gets the mechanical model, gives error compensation formula caused by the radius change of the yarn group in the unwinding side, designs the closed-loop control system and utilizes the dynamical- integral PID control strategy to achieve the tension control during the process of the cylindrical winding.展开更多
Protein tyrosine phosphatase 1B (PTP1B) plays an important role as a negative regulator and has been proved to be an effective target for the treatment of type 2 diabetes mellitus. Bis-(2,3-dibromo-4,5-dihydroxyphe...Protein tyrosine phosphatase 1B (PTP1B) plays an important role as a negative regulator and has been proved to be an effective target for the treatment of type 2 diabetes mellitus. Bis-(2,3-dibromo-4,5-dihydroxyphenyl)-methane 7 was first reported as a natural bromophenol with significant inhibition against PTP1B which was isolated from red algae Rhodomela conrervoides. Intrigued by its astonishing activity (IC50 = 2.4 μmol/L), compound 7 was synthesized with the overall yield of 24% and evaluated for its PTPIB inhibitory activity compared with natural compound.展开更多
BACKGROUND: Many studies have showed that apoptosis of endothelial cells plays a curial role in the progress of sepsis. But the role of simvastatin in apoptosis of endothelial cells induced by sepsis is not clear. The...BACKGROUND: Many studies have showed that apoptosis of endothelial cells plays a curial role in the progress of sepsis. But the role of simvastatin in apoptosis of endothelial cells induced by sepsis is not clear. The present study aimed to investigate the role of simvastatin in apoptosis of endothelial cells induced by sepsis and its mechanism.METHODS: Human umbilical vein endothelial cells(HUVECs) were randomly divided into three groups: control group, sepsis serum intervention group(sepsis group) and simvastatin+sepsis serum intervention group(simvastatin group). After 24-hour incubation with corresponding culture medium, the relative growth rate of HUVECS in different groups was detected by MTT assay; the apoptosis of HUVECs was detected by Hoechst33258 assay and fl ow cytometry; and the expression of the Bcl-2 and Bax genes of HUVECs was detected by PCR.RESULTS: Compared with the sepsis group, HUVECs in the simvastatin group had a higher relative growth rate. Apoptotic HUVECs decreased significantly in the simvastatin group in comparison with the sepsis group. Expression of the Bcl-2 gene in HUVECs decreased obviously, but the expression of the Bax gene increased obviously after 24-hour incubation with sepsis serum; however, the expression of the Bcl-2 and Bax genes was just the opposite in the simvastatin group.CONCLUSIONS: Our study suggests that simvastatin can inhibit apoptosis of endothelial cells induced by sepsis through upregulating the expression of Bcl-2 and downregulating Bax. It may be one of the mechanisms for simvastatin to treat sepsis.展开更多
A new efficient coupling relationship description method has been developed to provide an automated and visualized way to multidisciplinary design optimization (MDO) modeling and solving. The disciplinary relation mat...A new efficient coupling relationship description method has been developed to provide an automated and visualized way to multidisciplinary design optimization (MDO) modeling and solving. The disciplinary relation matrix (DRM) is proposed to describe the coupling relationship according to disciplinary input/output variables, and the MDO definition has been reformulated to adopt the new interfaces. Based on these, a universal MDO solving procedure is proposed to establish an automated and efficient way for MDO modeling and solving. Through a simple and convenient initial configuration, MDO problems can be solved using any of available MDO architectures with no further effort. Several examples are used to verify the proposed MDO modeling and solving process. Result shows that the DRM method has the ability to simplify and automate the MDO procedure, and the related MDO framework can evaluate the MDO problem automatically and efficiently.展开更多
Bone fracture occurs in stroke patients at different times during the recovery phase, prolonging recovery time and increasing medical costs. In this review, we discuss the potential risk factors for post-stroke bone f...Bone fracture occurs in stroke patients at different times during the recovery phase, prolonging recovery time and increasing medical costs. In this review, we discuss the potential risk factors for post-stroke bone fracture and preventive methods. Most post-stroke bone fractures occur in the lower extremities, indicating fragile bones are a risk factor. Motor changes, including posture, mobility, and balance post-stroke contribute to bone loss and thus increase risk of bone fracture. Bone mineral density is a useful indicator for bone resorption, useful to identify patients at risk of post-stroke bone fracture. Calcium supplementation was previously regarded as a useful treatment during physical rehabilitation. However, recent data suggests calcium supplementation has a negative impact on atherosclerotic conditions. Vitamin D intake may prevent osteoporosis and fractures in patients with stroke. Although drugs such as teriparatide show some benefits in preventing osteoporosis, additional clinical trials are needed to determine the most effective conditions for post-stroke applications.展开更多
With the support of density functional theory(DFT)calculation,the amelioration of sintering and dielectric properties of the Mg_(3)B_(2)O_(6)(MBO)ceramic was realized through the substitution of magnesium with nickel....With the support of density functional theory(DFT)calculation,the amelioration of sintering and dielectric properties of the Mg_(3)B_(2)O_(6)(MBO)ceramic was realized through the substitution of magnesium with nickel.The TE-mode cylindrical cavity method was used to measure the dielectric properties at different frequencies.The thermo-mechanical analysis and simultaneous thermal analysis were used to characterize the chemical and mechanical properties.The phase composition was determined through the X-ray diffraction(XRD)and Raman spectrum.The microstructure was investigated using the scanning electron microscopy(SEM).Magnesium substitution with nickel(4 mol%)could ionize the B-0 bond of BO3,modify the vibration mode,improve the order degree,densify the microstmcture,decrease the intrinsic densification temperature,and ameliorate the dielectric properties of the MBO ceramics.The maximum values were achieved for the ceramics with 4 mol%nickel and sintered at 1175℃,that is,97.2%for relative density,72,600 GHz(10 GHz),75,600 GHz(11.4 GHz),and 92,200 GHz(15 GHz)for Q×f,7.1(10 GHz),7.01(11.4 GHz),and 6.91(15 GHz)for£r,and-56.3 ppm/℃ for if.展开更多
Digitizing the land surface temperature(T_(s))and surface soil moisture(m _(v))is essential for developing the intelligent Digital Earth.Here,we developed a two parameter physical-based passive microwave remote sensin...Digitizing the land surface temperature(T_(s))and surface soil moisture(m _(v))is essential for developing the intelligent Digital Earth.Here,we developed a two parameter physical-based passive microwave remote sensing model for jointly retrieving T_(s) and m_(v) using the dual-polarized T_(b) of Aqua satellite advanced microwave scanning radiometer(AMSR-E)C-band(6.9 GHz)based on the simplified radiative transfer equation.Validation using in situ T_(s) and m_(v) in southern China showed the average root mean square errors(RMSE)of T s and m_(v) retrievals reach 2.42 K(R^(2)=0.61,n=351)and 0.025 g cm^(−3)(R^(2)=0.68,n=663),respectively.The results were also validated using global in situ T_(s)(n=2362)and m_(v)(n=1657)of International Soil Moisture Network.The corresponding RMSE are 3.44 k(R 2=0.86)and 0.039 g cm^(−3)(R^(2)=0.83),respectively.The monthly variations of model-derived Ts and mv are highly consistent with those of the Moderate Resolution Imaging Spectroradiometer T_(s)(R^(2)=0.57;RMSE=2.91 k)and ECV_SM m_(v)(R^(2)=0.51;RMSE=0.045 g cm^(−3)),respectively.Overall,this paper indicates an effective way to jointly modeling T_(s) and m_(v) using passive microwave remote sensing.展开更多
Non-contacting finger seals represent an advanced non-contacting and compliant seal in gas turbine sealing technology.This paper proposes a new structure of noncontacting finger seals with double interlocking pads.The...Non-contacting finger seals represent an advanced non-contacting and compliant seal in gas turbine sealing technology.This paper proposes a new structure of noncontacting finger seals with double interlocking pads.The numerical analysis model based on the thermo-fluid-structure coupling method for the new type finger seal was established.The influence of working conditions on leakage of the seal was studied and compared with the single padded non-contacting finger seal.The results show that the interface between the bottom of the finger pad and rotor surface is the main leakage path that forms the gas film with obvious variations of pressure and flow velocity.Under high temperature and high pressure operating conditions,the hydrodynamic effect of the gas film is enhanced,and lifting force is significantly improved.The deformation of fingers is composed of elastic deformation and thermal deformation.At room temperature,the deformation of fingers is mainly elastic deformation and points to the center of the rotor,which reduces the gas film clearance.The deformation of fingers at high temperature and high pressure creates a circumferentially convergent gap between the bottom of the pad and the rotor,which is beneficial to improve the loading capacity and to reduce leakage of the seal.Compared with the typical single padded noncontacting finger seal,the double interlocking padded finger seal proposed in this paper reduces the leakage factor by about 37%,which provides an advanced seal concept with the potential to improve sealing performance under high temperature and high pressure working conditions.展开更多
In this study, low-temperature fired CaMg1−xLi2xSi2O6 microwave dielectric ceramics were prepared via the traditional solid-state reaction method. In this process, 0.4 wt% Li2CO3-B2O3-SiO2-CaCO3-Al2O3 (LBSCA) glass wa...In this study, low-temperature fired CaMg1−xLi2xSi2O6 microwave dielectric ceramics were prepared via the traditional solid-state reaction method. In this process, 0.4 wt% Li2CO3-B2O3-SiO2-CaCO3-Al2O3 (LBSCA) glass was added as a sintering aid. The results showed that ceramics consisted of CaMgSi2O6 as the main phase. The second phases were CaSiO3 always existing and Li2SiO3 occurring at substitution content x > 0.05. Li+ substitution effectively lowered sintering temperature due to 0.4 wt% LBSCA and contributed to grain densification, and the most homogeneous morphology could be observed at x = 0.05. The effects of relative density, the second phase, and ionic polarizability on dielectric constant (εr) were investigated. The quality factor (Q × f) varied with packing fraction that concerned the second phase. Moreover, the temperature coefficient of the resonant frequency (τf) was influenced by MgO6 octahedral distortion and bond valence. Excellent dielectric properties of the CaMg1−xLi2xSi2O6 ceramic was exhibited at x = 0.05 with εr = 7.44, Q × f = 41,017 GHz (f = 15.1638 GHz), and τf = −59.3 ppm/°C when sintered at 900 °C. It had a good application prospect in the field of low-temperature co-fired ceramic (LTCC) substrate and devices.展开更多
文摘目的:探讨南阳市第一人民医院抗菌药物的使用情况及与常见的细菌耐药的相关性。方法:收集南阳市第一人民医院2018年1月至2021年12月临床患者送检的阳性标本,统计临床标本分离病原菌检出情况、常见抗菌药物消耗情况以及常见的革兰氏阴性杆菌、阳性球菌对抗菌药物产生的耐药率(%)与抗菌药物用药频度(Frequency of defined daily doses,DDDs)的相关性。结果:我院2018年至2021年抗菌药物DDDs较高的抗菌药物依次为美洛西林、头孢他啶、哌拉西林他唑巴坦,检出率较高的病原菌分别为大肠埃希氏菌、肺炎克雷伯菌、金黄色葡萄球菌等。大肠埃希菌产生的耐药率与哌拉西林他唑巴坦、头孢呋辛钠DDDs均有相关性(r=-0.107、0.432);肺炎克雷伯菌产生的耐药率与哌拉西林他唑巴坦、左氧氟沙星氯化钠、头孢呋辛钠DDDs呈正相关(r=0.410、0.720、0.420);铜绿假单胞菌与哌拉西林他唑巴坦、头孢哌酮舒巴坦钠DDDs呈正相关(r=0.716、0.933);金黄色葡萄球菌的耐药率与左氧氟沙星DDDs呈正相关(r=0.661);肺炎链球菌产生的耐药率与左氧氟沙星、头孢呋辛钠DDDs均存在正相关关系(r=0.416和0.482)。结论:抗菌药物的DDDs与常见细菌产生的耐药性具有一定的相关性,我院应严格控制抗菌药物的DDDs,根据感染性病种及药敏试验结果选择适当的抗菌药,加强常见病原菌的耐药监测。
文摘Glibenclamide, a blocker of ATP-sensitive potassium channels, has been found to induce apoptosis in some cell types, including pancreatic beta-cells. Since autophagy plays doubleedged roles in pancreatic beta-cell survival, frequently through cross-talking with apoptosis, we investigated if glibenclamide induced autophagy in INS-1 rat insulinoma cells and the influence of autophagy on apoptosis. Mammalian target of rapamycin (mTOR) is a negative regulator of autophagy. As one of the substrates of mTOR, p70 S6 kinase (p70 S6K) is phosphorylated upon mTOR activation. Our results showed that glibenclamide induced an elevated protein level of the autophagy marker LC3-II, while decreasing phosphorylated p70 S6K, indicative of inhibition on mTOR signaling in INS-1 cells. Furthermore, inhibiting glibenclamide-induced autophagy via knocking down the autophagy essential gene Atg7 decreased cell viability and increased apoptosis in INS-1 cells. Our results indicate that glibenclamide induces autophagy in INS-1 cells, and that autophagy activation is exerting a protective activity against apoptosis.
基金The National Natural Science Foundation of China under contract No.41906019.
文摘Chlorophyll a concentration(CHL)is an important proxy of the marine ecological environment and phytoplankton production.Long-term trends in CHL of the South China Sea(SCS)reflect the changes in the ecosystem’s productivity and functionality in the regional carbon cycle.In this study,we applied a previously reconstructed 15-a(2005–2019)CHL product,which has a complete coverage at 4 km and daily resolutions,to analyze the long-term trends of CHL in the SCS.Quantile regression was used to elaborate on the long-term trends of high,median,and low CHL values,as an extended method of conventional linear regression.The results showed downward trends of the SCS CHL for the 75th,50th,and 25th quantile in the past 15 a,which were−0.0040 mg/(m^(3)·a)(−1.62%per year),−0.0023 mg/(m^(3)·a)(−1.10%per year),and−0.0019 mg/(m^(3)·a)(−1.01%per year).The negative trends in winter(November to March)were more prominent than those in summer(May to September).In terms of spatial distribution,the downward trend was more significant in regions with higher CHL.These led to a reduced standard deviation of CHL over time and space.We further explored the influence of various dynamic factors on CHL trends for the entire SCS and two typical systems(winter Luzon Strait(LZ)and summer Vietnam Upwelling System(SV))with single-variate linear regression and multivariate Random Forest analysis.The multivariate analysis suggested the CHL trend pattern can be best explained by the trends of wind speed and mixed-layer depth.The divergent importance of controlling factors for LZ and SV can explain the different CHL trends for the two systems.This study expanded our understanding of the long-term changes of CHL in the SCS and provided a reference for investigating changes in the marine ecosystem.
基金supported by the National Natural Science Foundation of China(Grant Nos.61771104 and 62071106)Jiangxi Innovative Talent Program,and Sichuan Science and Technology Program(Grant No.2021JDTD0026)。
文摘With the help of the first principle calculation,the solid-state reaction experiment was conducted to investigate the alteration in the sintering and the microwave dielectric properties of Mg_(3)B_(2)O_(6)ceramic with many Zn^(2+)substitutions.These properties were characterized using the scanning electron microscopy,network analyzer,X-ray diffraction,Raman spectroscopy,energy-dispersive spectroscopy,and thermomechanical and differential-thermal analyses.The coexistence of Mg_(3)B_(2)O_(6),Mg_(2)B_(2)O_(5)and ZnO ceramics could be observed with increasing Zn^(2+)addition,and the lattice distortion occurred in the Mg_(2)B_(2)O_(5)and Mg_(3)B_(2)O_(6)ceramics due to the substitution of Mg^(2+)with Zn^(2+).The electron density and the bond property of the MgO_(6)octahedron changed,and a quantitative method was used to discuss the variation in sintering,substitution and phase formation properties.The densification window was decreased to 1100℃,and the dielectric properties improved with the formation of a three-phase borate solid solution(dielectric constant=6.73,quality factor=112,000 GHz at 16 GHz(Q=7000),temperature coefficient of resonant frequency=-61.2 ppm℃^(-1),and relative density=97.0%).
文摘The constant winding tension can make the filament arranged in order. The stress distribution between the filament balance fully gives play to the enhancement of filament, and increases the intensive workload of the composite winding material. This paper conducts the mechanical analysis for the unwinding roller and tension measuring roller of the cylindrical winding machine so that gets the mechanical model, gives error compensation formula caused by the radius change of the yarn group in the unwinding side, designs the closed-loop control system and utilizes the dynamical- integral PID control strategy to achieve the tension control during the process of the cylindrical winding.
基金the National Center for Drug Screening (Shanghai,PR China) for supplying data on PTP1B inhibitory activities of compoundssupported by the National 863 projects (Nos.2007AA09Z410 and 2007AA091604).
文摘Protein tyrosine phosphatase 1B (PTP1B) plays an important role as a negative regulator and has been proved to be an effective target for the treatment of type 2 diabetes mellitus. Bis-(2,3-dibromo-4,5-dihydroxyphenyl)-methane 7 was first reported as a natural bromophenol with significant inhibition against PTP1B which was isolated from red algae Rhodomela conrervoides. Intrigued by its astonishing activity (IC50 = 2.4 μmol/L), compound 7 was synthesized with the overall yield of 24% and evaluated for its PTPIB inhibitory activity compared with natural compound.
基金supported by grants from the Medical Research Foundation of Hunan Province(B2013-040)the Science and Technology Development Foundation of Hengyang City(2010kj38)
文摘BACKGROUND: Many studies have showed that apoptosis of endothelial cells plays a curial role in the progress of sepsis. But the role of simvastatin in apoptosis of endothelial cells induced by sepsis is not clear. The present study aimed to investigate the role of simvastatin in apoptosis of endothelial cells induced by sepsis and its mechanism.METHODS: Human umbilical vein endothelial cells(HUVECs) were randomly divided into three groups: control group, sepsis serum intervention group(sepsis group) and simvastatin+sepsis serum intervention group(simvastatin group). After 24-hour incubation with corresponding culture medium, the relative growth rate of HUVECS in different groups was detected by MTT assay; the apoptosis of HUVECs was detected by Hoechst33258 assay and fl ow cytometry; and the expression of the Bcl-2 and Bax genes of HUVECs was detected by PCR.RESULTS: Compared with the sepsis group, HUVECs in the simvastatin group had a higher relative growth rate. Apoptotic HUVECs decreased significantly in the simvastatin group in comparison with the sepsis group. Expression of the Bcl-2 gene in HUVECs decreased obviously, but the expression of the Bax gene increased obviously after 24-hour incubation with sepsis serum; however, the expression of the Bcl-2 and Bax genes was just the opposite in the simvastatin group.CONCLUSIONS: Our study suggests that simvastatin can inhibit apoptosis of endothelial cells induced by sepsis through upregulating the expression of Bcl-2 and downregulating Bax. It may be one of the mechanisms for simvastatin to treat sepsis.
基金supported by the National Natural Science Foundation of China(51505385)Shanghai Aerospace Science and Technology Innovation Foundation(SAST2015010)the Defense Basic Research Program(JCKY2016204B102)
文摘A new efficient coupling relationship description method has been developed to provide an automated and visualized way to multidisciplinary design optimization (MDO) modeling and solving. The disciplinary relation matrix (DRM) is proposed to describe the coupling relationship according to disciplinary input/output variables, and the MDO definition has been reformulated to adopt the new interfaces. Based on these, a universal MDO solving procedure is proposed to establish an automated and efficient way for MDO modeling and solving. Through a simple and convenient initial configuration, MDO problems can be solved using any of available MDO architectures with no further effort. Several examples are used to verify the proposed MDO modeling and solving process. Result shows that the DRM method has the ability to simplify and automate the MDO procedure, and the related MDO framework can evaluate the MDO problem automatically and efficiently.
基金National Institutes of Health,Nos.R01 NS027713,R01 HL122774 and R21 NS083788the Michael Ryan Zodda Foundation and UCSF Research Evaluation and Allocation Committee(REAC)
文摘Bone fracture occurs in stroke patients at different times during the recovery phase, prolonging recovery time and increasing medical costs. In this review, we discuss the potential risk factors for post-stroke bone fracture and preventive methods. Most post-stroke bone fractures occur in the lower extremities, indicating fragile bones are a risk factor. Motor changes, including posture, mobility, and balance post-stroke contribute to bone loss and thus increase risk of bone fracture. Bone mineral density is a useful indicator for bone resorption, useful to identify patients at risk of post-stroke bone fracture. Calcium supplementation was previously regarded as a useful treatment during physical rehabilitation. However, recent data suggests calcium supplementation has a negative impact on atherosclerotic conditions. Vitamin D intake may prevent osteoporosis and fractures in patients with stroke. Although drugs such as teriparatide show some benefits in preventing osteoporosis, additional clinical trials are needed to determine the most effective conditions for post-stroke applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.61771104 and 62071106)the Jiangxi Innovative Talent Program,and the Sichuan Science and Technology Program(Grant No.2021JDTD0026).
文摘With the support of density functional theory(DFT)calculation,the amelioration of sintering and dielectric properties of the Mg_(3)B_(2)O_(6)(MBO)ceramic was realized through the substitution of magnesium with nickel.The TE-mode cylindrical cavity method was used to measure the dielectric properties at different frequencies.The thermo-mechanical analysis and simultaneous thermal analysis were used to characterize the chemical and mechanical properties.The phase composition was determined through the X-ray diffraction(XRD)and Raman spectrum.The microstructure was investigated using the scanning electron microscopy(SEM).Magnesium substitution with nickel(4 mol%)could ionize the B-0 bond of BO3,modify the vibration mode,improve the order degree,densify the microstmcture,decrease the intrinsic densification temperature,and ameliorate the dielectric properties of the MBO ceramics.The maximum values were achieved for the ceramics with 4 mol%nickel and sintered at 1175℃,that is,97.2%for relative density,72,600 GHz(10 GHz),75,600 GHz(11.4 GHz),and 92,200 GHz(15 GHz)for Q×f,7.1(10 GHz),7.01(11.4 GHz),and 6.91(15 GHz)for£r,and-56.3 ppm/℃ for if.
基金This study was supported by the National Natural Science Foundation of China[grant numbers 31500357,41401055,41430529,41601444]the Natural Science Foundation of Guangdong Province,China[grant numbers 2014A030310233,2015A030313809,2015A030313811]+4 种基金the Science and Technology Plan Fund of Guangzhou City,China[grant numbers 201510010240,201610010134]the Water Resource Science and Technology Innovation Program of Guangdong Province[grant numbers 2016-16,2015-14]the Scientific Platform and Innovation Capability Construction Program of GDAS[2016GDASPT-0210]the High-Level Leading Talent Introduction Program of GDAS[2016GDASRC-0101]Fujian Collaborative Innovation Center for Big Data Applications in Governments.
文摘Digitizing the land surface temperature(T_(s))and surface soil moisture(m _(v))is essential for developing the intelligent Digital Earth.Here,we developed a two parameter physical-based passive microwave remote sensing model for jointly retrieving T_(s) and m_(v) using the dual-polarized T_(b) of Aqua satellite advanced microwave scanning radiometer(AMSR-E)C-band(6.9 GHz)based on the simplified radiative transfer equation.Validation using in situ T_(s) and m_(v) in southern China showed the average root mean square errors(RMSE)of T s and m_(v) retrievals reach 2.42 K(R^(2)=0.61,n=351)and 0.025 g cm^(−3)(R^(2)=0.68,n=663),respectively.The results were also validated using global in situ T_(s)(n=2362)and m_(v)(n=1657)of International Soil Moisture Network.The corresponding RMSE are 3.44 k(R 2=0.86)and 0.039 g cm^(−3)(R^(2)=0.83),respectively.The monthly variations of model-derived Ts and mv are highly consistent with those of the Moderate Resolution Imaging Spectroradiometer T_(s)(R^(2)=0.57;RMSE=2.91 k)and ECV_SM m_(v)(R^(2)=0.51;RMSE=0.045 g cm^(−3)),respectively.Overall,this paper indicates an effective way to jointly modeling T_(s) and m_(v) using passive microwave remote sensing.
文摘Non-contacting finger seals represent an advanced non-contacting and compliant seal in gas turbine sealing technology.This paper proposes a new structure of noncontacting finger seals with double interlocking pads.The numerical analysis model based on the thermo-fluid-structure coupling method for the new type finger seal was established.The influence of working conditions on leakage of the seal was studied and compared with the single padded non-contacting finger seal.The results show that the interface between the bottom of the finger pad and rotor surface is the main leakage path that forms the gas film with obvious variations of pressure and flow velocity.Under high temperature and high pressure operating conditions,the hydrodynamic effect of the gas film is enhanced,and lifting force is significantly improved.The deformation of fingers is composed of elastic deformation and thermal deformation.At room temperature,the deformation of fingers is mainly elastic deformation and points to the center of the rotor,which reduces the gas film clearance.The deformation of fingers at high temperature and high pressure creates a circumferentially convergent gap between the bottom of the pad and the rotor,which is beneficial to improve the loading capacity and to reduce leakage of the seal.Compared with the typical single padded noncontacting finger seal,the double interlocking padded finger seal proposed in this paper reduces the leakage factor by about 37%,which provides an advanced seal concept with the potential to improve sealing performance under high temperature and high pressure working conditions.
基金This study was supported by the National Natural Science Foundation of China(Grant Nos.61771104 and U1809215).
文摘In this study, low-temperature fired CaMg1−xLi2xSi2O6 microwave dielectric ceramics were prepared via the traditional solid-state reaction method. In this process, 0.4 wt% Li2CO3-B2O3-SiO2-CaCO3-Al2O3 (LBSCA) glass was added as a sintering aid. The results showed that ceramics consisted of CaMgSi2O6 as the main phase. The second phases were CaSiO3 always existing and Li2SiO3 occurring at substitution content x > 0.05. Li+ substitution effectively lowered sintering temperature due to 0.4 wt% LBSCA and contributed to grain densification, and the most homogeneous morphology could be observed at x = 0.05. The effects of relative density, the second phase, and ionic polarizability on dielectric constant (εr) were investigated. The quality factor (Q × f) varied with packing fraction that concerned the second phase. Moreover, the temperature coefficient of the resonant frequency (τf) was influenced by MgO6 octahedral distortion and bond valence. Excellent dielectric properties of the CaMg1−xLi2xSi2O6 ceramic was exhibited at x = 0.05 with εr = 7.44, Q × f = 41,017 GHz (f = 15.1638 GHz), and τf = −59.3 ppm/°C when sintered at 900 °C. It had a good application prospect in the field of low-temperature co-fired ceramic (LTCC) substrate and devices.