In the past few years,attention has mainly been focused on the symmetric Brownian motor(BM)with Gaussian noises,whose current and energy conversion efficiency are very low.Here,we investigate the operating performance...In the past few years,attention has mainly been focused on the symmetric Brownian motor(BM)with Gaussian noises,whose current and energy conversion efficiency are very low.Here,we investigate the operating performance of the symmetric BM subjected to Lévy noise.Through numerical simulations,it is found that the operating performance of the motor can be greatly improved in asymmetric Lévy noise.Without any load,the Lévy noises with smaller stable indexes can let the motor give rise to a much greater current.With a load,the energy conversion efficiency of the motor can be enhanced by adjusting the stable indexes of the Lévy noises with symmetry breaking.The results of this research are of great significance for opening up BM’s intrinsic physical mechanism and promoting the development of nanotechnology.展开更多
Objective: To refine the infectious doses of enteric bacterial pathogens in animal assays and vaccine clinical trials by studying the invasion kinetics of five bacterial pathogens with human intestinal cells.Methods: ...Objective: To refine the infectious doses of enteric bacterial pathogens in animal assays and vaccine clinical trials by studying the invasion kinetics of five bacterial pathogens with human intestinal cells.Methods: Utilizing in vitro cultured cell invasion assays with gentamicin-killing step,the invasive effects were analyzed in foodborne pathogens including Salmonella,Shigella, Yersinia, Escherichia coli(E. coli) O157 and opportunistic pathogens Citrobacter in human embryonic intestine 407 cells and ileocecum HCT-8 cells at multiplicities of infection(MOIs) of 0.04–4 000.00 E. coli HS served as a noninvasive control.Results: The study results showed that the bacterial invasive efficiency and the average number of internalized bacteria per host cell changed with different starting MOIs. Higher starting MOIs did not always produce more bacterial internalization. The bacterial invasion effects varied with different bacterial strains and host cell lines. E. coli O157:H7 did invade human ileocecum HCT-8 cells.Conclusions: This study shows that these bacteria possess different invasive patterns at various starting MOIs and also in different cell lines. The results could help to figure out the appropriate infectious doses of the bacteria in animal assays and in vaccine clinical trials. The bacterial invasion kinetics is also valuable in evaluating the safety and efficacy of live attenuated bacterial vaccines.展开更多
准确测定粗晶热影响区(coarse-grained heat affected zone,CGHAZ)的热循环曲线是分析窄间隙焊接(narrow gap welding,NGW)冶金过程的基本前提.针对NGW CGHAZ狭小对焊接温度场测量带来的挑战,提出了一种新型的近侧壁隐藏布置热电偶测温...准确测定粗晶热影响区(coarse-grained heat affected zone,CGHAZ)的热循环曲线是分析窄间隙焊接(narrow gap welding,NGW)冶金过程的基本前提.针对NGW CGHAZ狭小对焊接温度场测量带来的挑战,提出了一种新型的近侧壁隐藏布置热电偶测温方法,成功获取了先进高强钢厚板窄间隙旋摆电弧熔化极活性气体保护焊(narrow gap metal active gas welding with arc swinging and shifting,NG-S^2MAG)立焊接头CGHAZ的热循环曲线,并通过理论分析计算和显微组织对比证实了新方案的可行性.结果表明,在实现坡口双侧侧壁"分时"熔合过程中,NG-S^2MAG立焊电弧的逐次逼近而后远离造成温度曲线的"多峰"性,使得母材CGHAZ在1 200℃以上的高温区停留时间较传统直通电弧MAG立焊短.展开更多
The two-step hydro-bulge forming technique was proposed to manufacture the ellipsoidal shell with the length ratio of the long axis to the short axis larger than 1.4. A central tube was introduced into the first step ...The two-step hydro-bulge forming technique was proposed to manufacture the ellipsoidal shell with the length ratio of the long axis to the short axis larger than 1.4. A central tube was introduced into the first step of the hydro-bulge forming process to constrain the over growth of the short axis during bulging,and then the central tube was replaced with two polar plates in the second step of the hydro-bulge forming process to manufacture an integral ellipsoidal shell. It is shown that the central tube restricts the growth of the short axis and simultaneously reduces the shrunk tendency of the long axis. The wrinkling occurs due to the latitudinal compressive stress at the equator at the early stage of hydro-bulge forming. However,with the increase of internal pressure,the compressive stress areas gradually decrease and finally the tensile latitudinal stress occupies approximately the whole shell,thus the wrinkles are eliminated. A sound ellipsoidal shell with the axis length ratio of 1.8 is obtained after two-step hydro bulging.展开更多
Arc sound is well known as the potential and available resource for monitoring and controlling of the weld penetration status,which is very important to the welding process quality control,so any attentions have been ...Arc sound is well known as the potential and available resource for monitoring and controlling of the weld penetration status,which is very important to the welding process quality control,so any attentions have been paid to the relationships between the arc sound and welding parameters.Some non-linear mapping models correlating the arc sound to welding parameters have been established with the help of neural networks.However,the research of utilizing arc sound to monitor and diagnose welding process is still in its infancy.A self-made real-time sensing system is applied to make a study of arc sound under typical penetration status,including partial penetration,unstable penetration,full penetration and excessive penetration,in metal inert-gas（MIG） flat tailored welding with spray transfer.Arc sound is pretreated by using wavelet de-noising and short-time windowing technologies,and its characteristics,characterizing weld penetration status,of time-domain,frequency-domain,cepstrum-domain and geometric-domain are extracted.Subsequently,high-dimensional eigenvector is constructed and feature-level parameters are successfully fused utilizing the concept of primary principal component analysis（PCA）.Ultimately,60-demensional eigenvector is replaced by the synthesis of 8-demensional vector,which achieves compression for feature space and provides technical supports for pattern classification of typical penetration status with the help of arc sound in MIG welding in the future.展开更多
BACKGROUND Aortic dissection(AD)and pulmonary embolism(PE)are both life-threatening disorders.Because of their conflicting treatments,treatment becomes difficult when they occur together,and there is no standard treat...BACKGROUND Aortic dissection(AD)and pulmonary embolism(PE)are both life-threatening disorders.Because of their conflicting treatments,treatment becomes difficult when they occur together,and there is no standard treatment protocol.CASE SUMMARY A 67-year-old man fell down the stairs due to syncope and was brought to our hospital as a confused and irritable patient who was uncooperative during the physical examination.Further examination of the head,chest and abdomen by computed tomography revealed a subdural hemorrhage,multiple rib fractures,a hemopneumothorax and a renal hematoma.He was admitted to the Emergency Intensive Care Unit and given a combination of oxygen therapy,external rib fixation,analgesia and enteral nutrition.The patient regained consciousness after 2 wk but complained of abdominal pain and dyspnea with an arterial partial pressure of oxygen of 8.66 kPa.Computed tomography angiograms confirmed that he had both AD and PE.We subsequently performed only nonsurgical treatment,including nasal high-flow oxygen therapy,nonsteroidal analgesia,amlodipine for blood pressure control,beta-blockers for heart rate control.Eight weeks after admission,the patient improved and was discharged from the hospital.CONCLUSION Patients with AD should be alerted to the possibility of a combined PE,the development of which may be associated with aortic compression.In patients with type B AD combined with low-risk PE,a nonsurgical,nonanticoagulant treatment regimen may be feasible.展开更多
Importance:Ventilator-associated pneumonia (VAP) is one of the most common complications after cardiac surgery in children with congenital heart disease (CHD).Early prediction of the incidence of VAP is important for ...Importance:Ventilator-associated pneumonia (VAP) is one of the most common complications after cardiac surgery in children with congenital heart disease (CHD).Early prediction of the incidence of VAP is important for clinical prevention and treatment.Objective:To determine the value of serum C-reactive protein (CRP) levels and the Pediatric Risk of Mortality Ⅲ (PRISM Ⅲ) score in predicting the risk of postoperative VAP in pediatric patients with CHD.Methods:We performed a retrospective review of clinical data of 481 pediatric patients with CHD who were admitted to our pediatric intensive care unit.These patients received mechanical ventilation for 48 hours or longer after corrective Surgery.On the basis of their clinical manifestations and laboratory results,patients were separated into two groups of those with VAP and those without VAP.CRP levels were measured and PRISM Ⅲ scores were collected within 12 hours of admission to the pediatric intensive care unit.The Pearson correlation coefficient was used to evaluate the association of CRP levels and the PRISM score with the occurrence of postoperative VAP.A linear regression model was constructed to obtain a joint function and receiver operating curves were used to assess the predictive value.Results:CRP levels and the PRISM Ⅲ score in the VAP group were significantly higher than those in the non-VAP group (P < 0.05).Receiver operating curves suggested that using CRP + the PRISM Ⅲ score to predict the incidence of VAP after congenial heart surgery was more accurate than using either of them alone (CRP + the PRISM Ⅲ score:sensitivity:53.2%,specificity:85.7%).When CRP + the PRISM Ⅲ score was greater than 45.460,patients were more likely to have VAP.Interpretation:Although using CRP levels plus the PRISM Ⅲ score to predict the incidence of VAP after congenial heart surgery is more accurate than using either of them alone,its predictive value is still limited.展开更多
The effect of hydrogen addition on the deformation behavior of coarse-grained Ti-55 alloys(~20μm)was studied by uniaxial tension tests at high temperature.The elongation of hydrogenated Ti-55 titanium alloy firstly i...The effect of hydrogen addition on the deformation behavior of coarse-grained Ti-55 alloys(~20μm)was studied by uniaxial tension tests at high temperature.The elongation of hydrogenated Ti-55 titanium alloy firstly increases and then decreases with hydrogen content increasing at 8750 C.The highest elongation of 243.8%is obtained in the hydrogenated alloy with 0.1 wt%H,and the peak stress reaches a minimum value of 29.0 MPa in the hydrogenated alloy with 0.3 wt%H.Compared with that of the unhydrogenated alloy,the elongation of the hydrogenated alloy with 0.1 wt%H increases by 41.3%and its peak stress decreases by 40.6%at 875℃.Hydrogen addition can promote the transformation of β phase and the dislocation movement.Appropriate hydrogen content can evidently improve the deformation properties of coarse-grained Ti-55 titanium alloy.展开更多
Employing the intermediate derivatization method（IDM）, twenty novel 1,3,4-oxadiazole derivatives containing arylpyrazoloxyl moiety were designed and synthesized. The structures of the title compounds were identified...Employing the intermediate derivatization method（IDM）, twenty novel 1,3,4-oxadiazole derivatives containing arylpyrazoloxyl moiety were designed and synthesized. The structures of the title compounds were identified by1 H NMR,13 C NMR, MS and elemental analyses, compound 4 was further identified by single-crystal X-ray diffraction. Antifungal activities against rice sheath blight（RSB） and sorghum anthracnose（SA） were evaluated by the mycelium linear growth rate method. Compounds 4, 16 and 20 displayed significant activities against RSB（EC50= 0.88 mg/L, 0.91 mg/L and 0.85 mg/L, respectively）,higher than the reference tebuconazole; While compound 3 exhibited higher activity against SA（EC50= 1.03 mg/L）, equal to commercial pyraclostrobin（EC50= 1.06 mg/L）. The study showed that compound 20 is a promising fungicide for further development.展开更多
Unlike DNA profiling,mRNA profiling is greatly affected by external factors.To analyze the influence of different stain carriers on the detectability of mRNA markers from bloodstains,this study examined 10 carriers,in...Unlike DNA profiling,mRNA profiling is greatly affected by external factors.To analyze the influence of different stain carriers on the detectability of mRNA markers from bloodstains,this study examined 10 carriers,including a knife,cotton swab,paper,plastic,leather,cement,chopsticks,clothes,ceramic block,and wall.After detecting five specific mRNA markers(HBA,HBB,ALAS2,GYPA,and SPTB)and the housekeeping gene B2M in peripheral blood samples,no statistically significant differences in the effects of the carriers were found.The results suggest that when performing mRNA testing on bloodstains,the effect of the stain carrier has little influence.展开更多
基金Project supported by the Research Group of Nonequilibrium Statistics(Grant No.14078206)Kunming University of Science and Technology,China.
文摘In the past few years,attention has mainly been focused on the symmetric Brownian motor(BM)with Gaussian noises,whose current and energy conversion efficiency are very low.Here,we investigate the operating performance of the symmetric BM subjected to Lévy noise.Through numerical simulations,it is found that the operating performance of the motor can be greatly improved in asymmetric Lévy noise.Without any load,the Lévy noises with smaller stable indexes can let the motor give rise to a much greater current.With a load,the energy conversion efficiency of the motor can be enhanced by adjusting the stable indexes of the Lévy noises with symmetry breaking.The results of this research are of great significance for opening up BM’s intrinsic physical mechanism and promoting the development of nanotechnology.
文摘Objective: To refine the infectious doses of enteric bacterial pathogens in animal assays and vaccine clinical trials by studying the invasion kinetics of five bacterial pathogens with human intestinal cells.Methods: Utilizing in vitro cultured cell invasion assays with gentamicin-killing step,the invasive effects were analyzed in foodborne pathogens including Salmonella,Shigella, Yersinia, Escherichia coli(E. coli) O157 and opportunistic pathogens Citrobacter in human embryonic intestine 407 cells and ileocecum HCT-8 cells at multiplicities of infection(MOIs) of 0.04–4 000.00 E. coli HS served as a noninvasive control.Results: The study results showed that the bacterial invasive efficiency and the average number of internalized bacteria per host cell changed with different starting MOIs. Higher starting MOIs did not always produce more bacterial internalization. The bacterial invasion effects varied with different bacterial strains and host cell lines. E. coli O157:H7 did invade human ileocecum HCT-8 cells.Conclusions: This study shows that these bacteria possess different invasive patterns at various starting MOIs and also in different cell lines. The results could help to figure out the appropriate infectious doses of the bacteria in animal assays and in vaccine clinical trials. The bacterial invasion kinetics is also valuable in evaluating the safety and efficacy of live attenuated bacterial vaccines.
文摘准确测定粗晶热影响区(coarse-grained heat affected zone,CGHAZ)的热循环曲线是分析窄间隙焊接(narrow gap welding,NGW)冶金过程的基本前提.针对NGW CGHAZ狭小对焊接温度场测量带来的挑战,提出了一种新型的近侧壁隐藏布置热电偶测温方法,成功获取了先进高强钢厚板窄间隙旋摆电弧熔化极活性气体保护焊(narrow gap metal active gas welding with arc swinging and shifting,NG-S^2MAG)立焊接头CGHAZ的热循环曲线,并通过理论分析计算和显微组织对比证实了新方案的可行性.结果表明,在实现坡口双侧侧壁"分时"熔合过程中,NG-S^2MAG立焊电弧的逐次逼近而后远离造成温度曲线的"多峰"性,使得母材CGHAZ在1 200℃以上的高温区停留时间较传统直通电弧MAG立焊短.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 59975022 and 50275034)
文摘The two-step hydro-bulge forming technique was proposed to manufacture the ellipsoidal shell with the length ratio of the long axis to the short axis larger than 1.4. A central tube was introduced into the first step of the hydro-bulge forming process to constrain the over growth of the short axis during bulging,and then the central tube was replaced with two polar plates in the second step of the hydro-bulge forming process to manufacture an integral ellipsoidal shell. It is shown that the central tube restricts the growth of the short axis and simultaneously reduces the shrunk tendency of the long axis. The wrinkling occurs due to the latitudinal compressive stress at the equator at the early stage of hydro-bulge forming. However,with the increase of internal pressure,the compressive stress areas gradually decrease and finally the tensile latitudinal stress occupies approximately the whole shell,thus the wrinkles are eliminated. A sound ellipsoidal shell with the axis length ratio of 1.8 is obtained after two-step hydro bulging.
基金supported by Harbin Academic Pacesetter Foundation of China (Grant No. RC2012XK006002)Zhegjiang Provincial Natural Science Foundation of China (Grant No. Y1110262)+2 种基金Ningbo Municipal Natural Science Foundation of China (Grant No. 2011A610148)Ningbo Municipal Major Industrial Support Project of China (Grant No.2011B1007)Heilongjiang Provincial Natural Science Foundation of China (Grant No. E2007-01)
文摘Arc sound is well known as the potential and available resource for monitoring and controlling of the weld penetration status,which is very important to the welding process quality control,so any attentions have been paid to the relationships between the arc sound and welding parameters.Some non-linear mapping models correlating the arc sound to welding parameters have been established with the help of neural networks.However,the research of utilizing arc sound to monitor and diagnose welding process is still in its infancy.A self-made real-time sensing system is applied to make a study of arc sound under typical penetration status,including partial penetration,unstable penetration,full penetration and excessive penetration,in metal inert-gas（MIG） flat tailored welding with spray transfer.Arc sound is pretreated by using wavelet de-noising and short-time windowing technologies,and its characteristics,characterizing weld penetration status,of time-domain,frequency-domain,cepstrum-domain and geometric-domain are extracted.Subsequently,high-dimensional eigenvector is constructed and feature-level parameters are successfully fused utilizing the concept of primary principal component analysis（PCA）.Ultimately,60-demensional eigenvector is replaced by the synthesis of 8-demensional vector,which achieves compression for feature space and provides technical supports for pattern classification of typical penetration status with the help of arc sound in MIG welding in the future.
文摘BACKGROUND Aortic dissection(AD)and pulmonary embolism(PE)are both life-threatening disorders.Because of their conflicting treatments,treatment becomes difficult when they occur together,and there is no standard treatment protocol.CASE SUMMARY A 67-year-old man fell down the stairs due to syncope and was brought to our hospital as a confused and irritable patient who was uncooperative during the physical examination.Further examination of the head,chest and abdomen by computed tomography revealed a subdural hemorrhage,multiple rib fractures,a hemopneumothorax and a renal hematoma.He was admitted to the Emergency Intensive Care Unit and given a combination of oxygen therapy,external rib fixation,analgesia and enteral nutrition.The patient regained consciousness after 2 wk but complained of abdominal pain and dyspnea with an arterial partial pressure of oxygen of 8.66 kPa.Computed tomography angiograms confirmed that he had both AD and PE.We subsequently performed only nonsurgical treatment,including nasal high-flow oxygen therapy,nonsteroidal analgesia,amlodipine for blood pressure control,beta-blockers for heart rate control.Eight weeks after admission,the patient improved and was discharged from the hospital.CONCLUSION Patients with AD should be alerted to the possibility of a combined PE,the development of which may be associated with aortic compression.In patients with type B AD combined with low-risk PE,a nonsurgical,nonanticoagulant treatment regimen may be feasible.
文摘Importance:Ventilator-associated pneumonia (VAP) is one of the most common complications after cardiac surgery in children with congenital heart disease (CHD).Early prediction of the incidence of VAP is important for clinical prevention and treatment.Objective:To determine the value of serum C-reactive protein (CRP) levels and the Pediatric Risk of Mortality Ⅲ (PRISM Ⅲ) score in predicting the risk of postoperative VAP in pediatric patients with CHD.Methods:We performed a retrospective review of clinical data of 481 pediatric patients with CHD who were admitted to our pediatric intensive care unit.These patients received mechanical ventilation for 48 hours or longer after corrective Surgery.On the basis of their clinical manifestations and laboratory results,patients were separated into two groups of those with VAP and those without VAP.CRP levels were measured and PRISM Ⅲ scores were collected within 12 hours of admission to the pediatric intensive care unit.The Pearson correlation coefficient was used to evaluate the association of CRP levels and the PRISM score with the occurrence of postoperative VAP.A linear regression model was constructed to obtain a joint function and receiver operating curves were used to assess the predictive value.Results:CRP levels and the PRISM Ⅲ score in the VAP group were significantly higher than those in the non-VAP group (P < 0.05).Receiver operating curves suggested that using CRP + the PRISM Ⅲ score to predict the incidence of VAP after congenial heart surgery was more accurate than using either of them alone (CRP + the PRISM Ⅲ score:sensitivity:53.2%,specificity:85.7%).When CRP + the PRISM Ⅲ score was greater than 45.460,patients were more likely to have VAP.Interpretation:Although using CRP levels plus the PRISM Ⅲ score to predict the incidence of VAP after congenial heart surgery is more accurate than using either of them alone,its predictive value is still limited.
基金financially supported by the Equipment Pre-research Fund(No.61409230408)the National Natural Science Foundation of China(No.51875350)the Program of Shanghai Excellent Academic Research Leadership(No.19XD1401900)。
文摘The effect of hydrogen addition on the deformation behavior of coarse-grained Ti-55 alloys(~20μm)was studied by uniaxial tension tests at high temperature.The elongation of hydrogenated Ti-55 titanium alloy firstly increases and then decreases with hydrogen content increasing at 8750 C.The highest elongation of 243.8%is obtained in the hydrogenated alloy with 0.1 wt%H,and the peak stress reaches a minimum value of 29.0 MPa in the hydrogenated alloy with 0.3 wt%H.Compared with that of the unhydrogenated alloy,the elongation of the hydrogenated alloy with 0.1 wt%H increases by 41.3%and its peak stress decreases by 40.6%at 875℃.Hydrogen addition can promote the transformation of β phase and the dislocation movement.Appropriate hydrogen content can evidently improve the deformation properties of coarse-grained Ti-55 titanium alloy.
基金financially supported partially by the Open Foundation of Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, China (No. ATM20170001)
文摘Employing the intermediate derivatization method（IDM）, twenty novel 1,3,4-oxadiazole derivatives containing arylpyrazoloxyl moiety were designed and synthesized. The structures of the title compounds were identified by1 H NMR,13 C NMR, MS and elemental analyses, compound 4 was further identified by single-crystal X-ray diffraction. Antifungal activities against rice sheath blight（RSB） and sorghum anthracnose（SA） were evaluated by the mycelium linear growth rate method. Compounds 4, 16 and 20 displayed significant activities against RSB（EC50= 0.88 mg/L, 0.91 mg/L and 0.85 mg/L, respectively）,higher than the reference tebuconazole; While compound 3 exhibited higher activity against SA（EC50= 1.03 mg/L）, equal to commercial pyraclostrobin（EC50= 1.06 mg/L）. The study showed that compound 20 is a promising fungicide for further development.
基金This study is funded by the basic research fund of the central public welfare research institute (2020JB001).
文摘Unlike DNA profiling,mRNA profiling is greatly affected by external factors.To analyze the influence of different stain carriers on the detectability of mRNA markers from bloodstains,this study examined 10 carriers,including a knife,cotton swab,paper,plastic,leather,cement,chopsticks,clothes,ceramic block,and wall.After detecting five specific mRNA markers(HBA,HBB,ALAS2,GYPA,and SPTB)and the housekeeping gene B2M in peripheral blood samples,no statistically significant differences in the effects of the carriers were found.The results suggest that when performing mRNA testing on bloodstains,the effect of the stain carrier has little influence.
