Tyrosine decarboxylase(TyDC)converts tyrosine to tyramine and plays a crucial role in secondary metabolite reactions,development,and stress responses in plants.Currently,the biological role of TyDC proteins from trees...Tyrosine decarboxylase(TyDC)converts tyrosine to tyramine and plays a crucial role in secondary metabolite reactions,development,and stress responses in plants.Currently,the biological role of TyDC proteins from trees is unknown.This study provided evidence showing that poplar PaTyDC4 functions in wood development and drought stress response.PaTyDC4 is preferentially expressed in wood-forming cells in stems.Overexpression of PaTyDC4 in poplars under the control of a xylem-specific promoter resulted in an increase in the ratio of xylem to phloem width,vessel cell area,and lignin accumulation in the stems.Biochemical assays revealed that PaTyDC4 was a component of the PaC3H17-PaMYB199 module-mediated pathway.In poplar stems,Pa TyDC4 expression was directly suppressed by PaMYB199,which was attenuated by the interaction between PaC3H17 and PaMYB199.In addition,Pa TyDC4 overexpression lines showed stronger drought tolerance than the wild-type lines,with higher photosynthetic capacity and lower levels of H_(2)O_(2).These results indicate that PaTyDC4 promotes xylem differentiation and lignin deposition during secondary growth and confers drought tolerance.Our findings may be useful for the genetic modification of biomass and drought resistance in trees.展开更多
Accurate aging diagnosis is crucial for the health and safety management of lithium-ion batteries in electric vehicles.Despite significant advancements achieved by data-driven methods,diagnosis accuracy remains constr...Accurate aging diagnosis is crucial for the health and safety management of lithium-ion batteries in electric vehicles.Despite significant advancements achieved by data-driven methods,diagnosis accuracy remains constrained by the high costs of check-up tests and the scarcity of labeled data.This paper presents a framework utilizing self-supervised machine learning to harness the potential of unlabeled data for diagnosing battery aging in electric vehicles during field operations.We validate our method using battery degradation datasets collected over more than two years from twenty real-world electric vehicles.Our analysis comprehensively addresses cell inconsistencies,physical interpretations,and charging uncertainties in real-world applications.This is achieved through self-supervised feature extraction using random short charging sequences in the main peak of incremental capacity curves.By leveraging inexpensive unlabeled data in a self-supervised approach,our method demonstrates improvements in average root mean square errors of 74.54%and 60.50%in the best and worst cases,respectively,compared to the supervised benchmark.This work underscores the potential of employing low-cost unlabeled data with self-supervised machine learning for effective battery health and safety management in realworld scenarios.展开更多
Objective To explore the effectiveness of a nutritional intervention in rescuers who screened positive for depression.Methods A randomized controlled trial design was employed.From June to August,2022,4,460 rescuers w...Objective To explore the effectiveness of a nutritional intervention in rescuers who screened positive for depression.Methods A randomized controlled trial design was employed.From June to August,2022,4,460 rescuers were screened using the Self-Rating Depression Scale(SDS),and 1,615 positive cases were identified.Thirty-one volunteers were recruited and randomly divided into a nutritional intervention group and a control group.The intervention group received health education and nutritional intervention(a compound paste therapy primarily composed of red roses and Seville orange flowers),while the control group received psychological education.SDS scores were assessed before and after the intervention.Results There was a statistically significant decline in SDS scores in the nutritional intervention group after the intervention(P<0.05).Furthermore,the SDS scores of the intervention group were significantly lower than those of the control group,both before and after the intervention(P<0.05).No severe adverse reactions were observed during safety evaluation.Conclusion The nutritional intervention effectively reduced the depression scores in rescuers.Early nutritional intervention is recommended for rescuers who initially screen positive for depression.展开更多
The variation of the principal stress of formations with the working and geo-mechanical conditions can trigger wellbore instabilities and adversely affect the well completion.A finite element model,based on the theory...The variation of the principal stress of formations with the working and geo-mechanical conditions can trigger wellbore instabilities and adversely affect the well completion.A finite element model,based on the theory of poro-elasticity and the Mohr-Coulomb rock damage criterion,is used here to analyze such a risk.The changes in wellbore stability before and after reservoir acidification are simulated for different pressure differences.The results indicate that the risk of wellbore instability grows with an increase in the production-pressure difference regardless of whether acidification is completed or not;the same is true for the instability area.After acidizing,the changes in the main geomechanical parameters(i.e.,elastic modulus,Poisson’s ratio,and rock strength)cause the maximum wellbore instability coefficient to increase.展开更多
For electric vehicles (EVs),it is necessary to improve endurance mileage by improving the efficiency.There exists a trend towards increasing the system voltage and switching frequency,contributing to improve charging ...For electric vehicles (EVs),it is necessary to improve endurance mileage by improving the efficiency.There exists a trend towards increasing the system voltage and switching frequency,contributing to improve charging speed and power density.However,this trend poses significant challenges for high-voltage and high-frequency motor controllers,which are plagued by increased switching losses and pronounced switching oscillations as consequences of hard switching.The deployment of soft switching technology presents a viable solution to mitigate these issues.This paper reviews the applications of soft switching technologies for three-phase inverters and classifies them based on distinct characteristics.For each type of inverter,the advantages and disadvantages are evaluated.Then,the paper introduces the research progress and control methods of soft switching inverters (SSIs).Moreover,it presents a comparative analysis among the conventional hard switching inverters (HSIs),an active clamping resonant DC link inverter (ACRDCLI) and an auxiliary resonant commuted pole inverter (ARCPI).Finally,the problems and prospects of soft switching technology applied to motor controllers for EVs are put forward.展开更多
The coiled tubing plugging has become the main means of plugging in gas Wells in Xinjiang. These Wells are deep and have high pressure, which can easily affect the fatigue life of the operating coiled tubing. In order...The coiled tubing plugging has become the main means of plugging in gas Wells in Xinjiang. These Wells are deep and have high pressure, which can easily affect the fatigue life of the operating coiled tubing. In order to improve the life of coiled tubing in high-pressure gas Wells, this paper studies the plugging conditions of coiled tubing in high-pressure ultra-deep Wells. Firstly, the cross section deformation of coiled tubing under high internal pressure is analyzed. Secondly, the factors influencing the fatigue life of coiled tubing and the influence of surface damage on the fatigue life of coiled tubing were studied. Finally, the mechanism of furrow damage caused by coiled tubing and the main measures to reduce furrow damage are analyzed. The following suggestions are made to improve the life of coiled tubing: select the right material and the right size coiled tubing;Use appropriate measures to prevent premature coiled tubing failure and reduce operating costs.展开更多
An enhanced leaching of Li fromα-spodumene was carried out using a mixture of hydrofluoric and sulfuric acid(HF/H2SO4)as the medium.Based on the optimized leaching conditions,the leaching kinetics of Li was investiga...An enhanced leaching of Li fromα-spodumene was carried out using a mixture of hydrofluoric and sulfuric acid(HF/H2SO4)as the medium.Based on the optimized leaching conditions,the leaching kinetics of Li was investigated in an ore/HF/H2SO4 ratio of 1:3:2 g:mL:mL with leaching temperature ranging from 50 to 100°C.The results indicate that the leaching kinetics of Li fitted well with a model based on the shrinking core model.In addition,the leaching rate of Li was controlled by chemical reactions and diffusion through the product layers.The apparent activation energy Ea was calculated to be 32.68 kJ/mol.Solid films were formed because of the generation of insoluble products such as cryolithionite(Na3Li2Al2F12),cryolite(Na3AlF6),calcium fluoride(CaF2),potassium cryolite(K2AlF5),aluminum fluoride(AlF3),and fluorosilicates(Na2SiF6 or KNaSiF6).Furthermore,the effects of the ore/HF ratio and leaching temperature on the leaching behavior of Li,Al and Si were investigated.The results indicate that the ore/HF ratio and leaching temperature could clearly affect the distribution of HF molecules on the leaching of Li,Al and Si,which are important for the selective leaching of Li over Al and Si with this fluorine-based chemical method.展开更多
In this paper, a two-dimensional axisymmetric fluid model was established to investigate the influence of nitrogen impurity content on the discharge pattern and the relevant discharge characteristics in an atmosphere ...In this paper, a two-dimensional axisymmetric fluid model was established to investigate the influence of nitrogen impurity content on the discharge pattern and the relevant discharge characteristics in an atmosphere pressure helium dielectric barrier discharge(DBD). The results indicated that when the nitrogen content was increased from 1 to 100 ppm, the discharge pattern evolved from a concentric-ring pattern into a uniform pattern, and then returned to the concentricring pattern. In this process, the discharge mode at the current peak moment transformed from glow mode into Townsend mode, and then returned to glow mode. Further analyses revealed that with the increase of impurity level, the rate of Penning ionization at the pre-ionization stage increased at first and decreased afterwards, resulting in a similar evolution pattern of seed electron level. This evolution trend was believed to be resulted from the competition between the N2 partial pressure and the consumption rate of metastable species. Moreover, the discharge uniformity was found positively correlated with the spatial uniformity of seed electron density as well as the seed electron level. The reason for this correlation was explained by the reduction of radial electric field strength and the promotion of seed electron uniformity as pre-ionization level increases. The results obtained in this work may help better understand the pattern formation mechanism of atmospheric helium DBD under the variation of N2 impurity level, thereby providing a possible means of regulating the discharge performance in practical application scenarios.展开更多
BACKGROUND: Etiologic organism is not frequently isolated despite multiple blood and lfuid cultures during management of pyogenic liver abscess (PLA). Such culture negative pyogen-ic liver abscess (CNPLA) is routinely...BACKGROUND: Etiologic organism is not frequently isolated despite multiple blood and lfuid cultures during management of pyogenic liver abscess (PLA). Such culture negative pyogen-ic liver abscess (CNPLA) is routinely managed by antibiotics targeted toKlebsiella pneumoniae. In this study, we evaluated the outcomes of such clinical practice. METHODS: All the patients with CNPLA andKlebsiella pneu-moniaePLA (KPPLA) admitted from January 2003 to Decem-ber 2011 were included in the study. A retrospective review of medical records was performed and demographic, clinical and outcome data were collected. RESULTS: A total of 528 patients were treated as CNPLA or KPPLA over the study period. CNPLA presented more com-monly with abdominal pain (P=0.024). KPPLA was more com-mon in older age (P=0.029) and was associated with thrombo-cytopenia (P=0.001), elevated creatinine (P=0.002), bilirubin (P=0.001), alanine aminotransferase (P=0.006) and C-reactive protein level (P=0.036). CNPLA patients tend to have anemia (P=0.015) and smaller abscess (P=0.008). There was no differ-ence in hospital stay (15.7 vs 16.8 days) or mortality (14.0% vs 11.0%). No patients required surgical drainage after initiation of medical therapy. CONCLUSION: Despite demographic and clinical differences between CNPLA and KPPLA, overall outcomes are not different.展开更多
BACKGROUND:Biliary atresia(BA) is a major cause of chronic cholestasis,a fatal disorder in infants.This study was undertaken to evaluate the safety and effectiveness of primary living donor liver transplantation(LDLT)...BACKGROUND:Biliary atresia(BA) is a major cause of chronic cholestasis,a fatal disorder in infants.This study was undertaken to evaluate the safety and effectiveness of primary living donor liver transplantation(LDLT) in comparison with the traditional first-line treatment,the Kasai procedure.METHODS:We assessed 28 children with BA at age of less than two years(3-21.3 months) who had undergone LDLT in two hospitals in Southwest China during the period of 2008-2011.Eighteen children who had had primary LDLT were included in a primary LDLT group,and ten children who had undergone the Kasai operation in a pre-Kasai group.All patients were followed up after discharge from the hospital.The records of the BA patients and donors were reviewed.RESULTS:The time of follow-up ranged 12-44.5 months with a median of 31 months.The 30-day and 1-year survival rates were 85.7% and 78.6%,respectively.There was no significant difference in the 30-day or 1-year survival between the two groups(83.3% vs 90% and 77.8% vs 80%,P】0.05).The main cause of death was hepatic artery thrombosis.There were more patients with complications who required intensive medical care or re-operation in the pre-Kasai group(8,80%) than in the primary LDLT group(9,50%)(P=0.226).But no significant differences were observed in operating time(9.3 vs 8.9 hours,P=0.77),intraoperative blood loss(208.6 vs 197.0 mL,P=0.84) and blood transfusion(105.6 vs 100.0 mL,P=0.91) between the two groups.The durations of ICU and hospital stay in the primary LDLT group and pre-Kasai group were 180.4 vs 157.7 hours(P=0.18) and 27 vs 29 days(P=0.29),respectively.CONCLUSIONS:Primary LDLT is a safe and efficient management for young pediatric patients with BA.Compared with the outcome of LDLT for patients receiving a previous Kasai operation,a similar survival rate and a low rate of re-operation and intensive medical care for patients with BA can be obtained.展开更多
Timataxel(13-(N-Boc-3-i-butylisoserinoyl-4,10-β-diacetoxy-2-α-benzoyloxy-5-β-20-epoxy-1,13-α-dihydroxy-9-oxo-19-norcyclopropa[g]tax-11-ene)), used to be called TM-2, is a novel semi-synthetic promising candidate f...Timataxel(13-(N-Boc-3-i-butylisoserinoyl-4,10-β-diacetoxy-2-α-benzoyloxy-5-β-20-epoxy-1,13-α-dihydroxy-9-oxo-19-norcyclopropa[g]tax-11-ene)), used to be called TM-2, is a novel semi-synthetic promising candidate for cancer treatment. However the preformulation study showed that TM-2 was insoluble and chemically instable in water, which would limit its application. This study aimed at the preparation of Timataxel lipid microspheres(TM-2 LMs)and investigated the difference between TM-2 LMs and TM-2 solution in pharmacokinetics. In this work, the final formulation was as follows: 0.10%(w/v) TM-2;10.00%(w/v) oil phase(long chain triglyceride:media chain triglyceride = 2.50%:7.50%);1.40%(w/v) phospholipid;0.02%(w/v) NaH2 PO4;2.25%(w/v) glycerin and water to a total volume of 100 ml.The particle size distribution, content and entrapment efficacy were 205.0 ± 43.3 nm, 101.00% and 99.12%, respectively. TM-2 LMs were stable during storage at 25 °C for 3 months, even under the condition of 60 °C and 4500 lx for 10 d. Phosphatidylethanolamine(PE) in phospholipid may contribute to the stability of TM-2 LMs. The pharmacokinetic parameters for TM-2 LMs were as follows: AUC(0-∞) 3663.71 μg/l h and the clearance 2.26 l/h/kg. As for solution, these parameters were 1712.52 μg/l h and 4.77 l/h/kg, respectively. The t1/2 of TM-2 LMs was similar to TM-2 solution. The pharmacokinetic results indicated that the AUC of TM-2 LMs was larger, the clearance was smaller than that of TM-2 solution. In a word, lipid microspheres were a promising drug delivery system for TM-2.展开更多
The China Seismo-Electromagnetic Satellite, launched into orbit from Jiuquan Satellite Launch Centre on February 2 nd, 2018, is China's first space satellite dedicated to geophysical exporation. The satellite carr...The China Seismo-Electromagnetic Satellite, launched into orbit from Jiuquan Satellite Launch Centre on February 2 nd, 2018, is China's first space satellite dedicated to geophysical exporation. The satellite carries eight scientific payloads including high-precision magnetometers to detect electromagnetic changes in space, in particular changes associated with global earthquake disasters. In order to encourage and facilitate use by geophysical scientists of data from the satellite's payloads, this paper introduces the application systems developed for the China Seismo-Electromagnetic Satellite by the Institute of Crustal Dynamics, China Earthquake Administration;these include platform construction, data classification, data storage, data format, and data access and acquisition.展开更多
The CSES(China seismic electromagnetic satellite) was launched on February 2, 2018 in a circular polar orbit at an altitude of～507 km. One of the main objectives of CSES is to search for and characterize ionospheric ...The CSES(China seismic electromagnetic satellite) was launched on February 2, 2018 in a circular polar orbit at an altitude of～507 km. One of the main objectives of CSES is to search for and characterize ionospheric perturbations that can be associated with seismic activities, to better understand the generation mechanism of such perturbations. Its scientific payload can measure a broad frequency range of electromagnetic waves and some important plasma parameters. This paper is a first-hand study of unusual observations recorded by the CSES over seismic regions prior to four earthquakes with M >7.0 since the satellite's launch. CSES detectors measured irregularities near the epicenter of these four earthquakes. It is already clear that data from instruments onboard the CSES will be of significant help in studies of characteristics of ionospheric perturbations related to earthquakes and their generation mechanisms.展开更多
基金Financial support was obtained from National Natural Science Foundation of China(Grant Nos.32101549 and 32201585)Natural Science Foundation of Shandong Province,China(Grant No.ZR202112010288)+2 种基金Science&Technology Specific Projects in Agricultural High-tech Industrial Demonstration Area of the Yellow River Delta(Grant No.2022SZX39)Technical Innovation and Application Development Special Project of Chongqing(Grant No.CSTB2022TIAD-LDX0013)the Taishan Scholar Program of Shandong(Grant No.tsqn202103092)。
文摘Tyrosine decarboxylase(TyDC)converts tyrosine to tyramine and plays a crucial role in secondary metabolite reactions,development,and stress responses in plants.Currently,the biological role of TyDC proteins from trees is unknown.This study provided evidence showing that poplar PaTyDC4 functions in wood development and drought stress response.PaTyDC4 is preferentially expressed in wood-forming cells in stems.Overexpression of PaTyDC4 in poplars under the control of a xylem-specific promoter resulted in an increase in the ratio of xylem to phloem width,vessel cell area,and lignin accumulation in the stems.Biochemical assays revealed that PaTyDC4 was a component of the PaC3H17-PaMYB199 module-mediated pathway.In poplar stems,Pa TyDC4 expression was directly suppressed by PaMYB199,which was attenuated by the interaction between PaC3H17 and PaMYB199.In addition,Pa TyDC4 overexpression lines showed stronger drought tolerance than the wild-type lines,with higher photosynthetic capacity and lower levels of H_(2)O_(2).These results indicate that PaTyDC4 promotes xylem differentiation and lignin deposition during secondary growth and confers drought tolerance.Our findings may be useful for the genetic modification of biomass and drought resistance in trees.
基金supported by the research project‘‘SafeDaBatt”(03EMF0409A)funded by the German Federal Ministry for Digital and Transport(BMDV)+2 种基金the National Key Research and Development Program of China(2022YFE0102700)the Key Research and Development Program of Shaanxi Province(2023-GHYB-05,2023-YBSF-104)the financial support from the China Scholarship Council(CSC)(202206567008)。
文摘Accurate aging diagnosis is crucial for the health and safety management of lithium-ion batteries in electric vehicles.Despite significant advancements achieved by data-driven methods,diagnosis accuracy remains constrained by the high costs of check-up tests and the scarcity of labeled data.This paper presents a framework utilizing self-supervised machine learning to harness the potential of unlabeled data for diagnosing battery aging in electric vehicles during field operations.We validate our method using battery degradation datasets collected over more than two years from twenty real-world electric vehicles.Our analysis comprehensively addresses cell inconsistencies,physical interpretations,and charging uncertainties in real-world applications.This is achieved through self-supervised feature extraction using random short charging sequences in the main peak of incremental capacity curves.By leveraging inexpensive unlabeled data in a self-supervised approach,our method demonstrates improvements in average root mean square errors of 74.54%and 60.50%in the best and worst cases,respectively,compared to the supervised benchmark.This work underscores the potential of employing low-cost unlabeled data with self-supervised machine learning for effective battery health and safety management in realworld scenarios.
基金Technical field fund of the basic strengthening plan of the military science and Technology Commission(2021-JCJQ-JJ-0528)The Project of Beijing Science and technology“capital characteristics”(Z181100001718007)+1 种基金Construction project of military medical teaching of PLA Medical College(145bxl090009000x)Central Military Health Care Commission(20BJZ46).
文摘Objective To explore the effectiveness of a nutritional intervention in rescuers who screened positive for depression.Methods A randomized controlled trial design was employed.From June to August,2022,4,460 rescuers were screened using the Self-Rating Depression Scale(SDS),and 1,615 positive cases were identified.Thirty-one volunteers were recruited and randomly divided into a nutritional intervention group and a control group.The intervention group received health education and nutritional intervention(a compound paste therapy primarily composed of red roses and Seville orange flowers),while the control group received psychological education.SDS scores were assessed before and after the intervention.Results There was a statistically significant decline in SDS scores in the nutritional intervention group after the intervention(P<0.05).Furthermore,the SDS scores of the intervention group were significantly lower than those of the control group,both before and after the intervention(P<0.05).No severe adverse reactions were observed during safety evaluation.Conclusion The nutritional intervention effectively reduced the depression scores in rescuers.Early nutritional intervention is recommended for rescuers who initially screen positive for depression.
基金This work is financially sponsored by Tarim Oilfield“Study on Adaptability Evaluation and Parameter Optimization of Completion Technology in Bozi Block,Tarim Oilfield”(Item Number:201021113436).
文摘The variation of the principal stress of formations with the working and geo-mechanical conditions can trigger wellbore instabilities and adversely affect the well completion.A finite element model,based on the theory of poro-elasticity and the Mohr-Coulomb rock damage criterion,is used here to analyze such a risk.The changes in wellbore stability before and after reservoir acidification are simulated for different pressure differences.The results indicate that the risk of wellbore instability grows with an increase in the production-pressure difference regardless of whether acidification is completed or not;the same is true for the instability area.After acidizing,the changes in the main geomechanical parameters(i.e.,elastic modulus,Poisson’s ratio,and rock strength)cause the maximum wellbore instability coefficient to increase.
基金funded by Tsinghua University-Weichai Power Intelligent Manufacturing Joint Research Institute (WCDL-GH-2022-0131)。
文摘For electric vehicles (EVs),it is necessary to improve endurance mileage by improving the efficiency.There exists a trend towards increasing the system voltage and switching frequency,contributing to improve charging speed and power density.However,this trend poses significant challenges for high-voltage and high-frequency motor controllers,which are plagued by increased switching losses and pronounced switching oscillations as consequences of hard switching.The deployment of soft switching technology presents a viable solution to mitigate these issues.This paper reviews the applications of soft switching technologies for three-phase inverters and classifies them based on distinct characteristics.For each type of inverter,the advantages and disadvantages are evaluated.Then,the paper introduces the research progress and control methods of soft switching inverters (SSIs).Moreover,it presents a comparative analysis among the conventional hard switching inverters (HSIs),an active clamping resonant DC link inverter (ACRDCLI) and an auxiliary resonant commuted pole inverter (ARCPI).Finally,the problems and prospects of soft switching technology applied to motor controllers for EVs are put forward.
文摘The coiled tubing plugging has become the main means of plugging in gas Wells in Xinjiang. These Wells are deep and have high pressure, which can easily affect the fatigue life of the operating coiled tubing. In order to improve the life of coiled tubing in high-pressure gas Wells, this paper studies the plugging conditions of coiled tubing in high-pressure ultra-deep Wells. Firstly, the cross section deformation of coiled tubing under high internal pressure is analyzed. Secondly, the factors influencing the fatigue life of coiled tubing and the influence of surface damage on the fatigue life of coiled tubing were studied. Finally, the mechanism of furrow damage caused by coiled tubing and the main measures to reduce furrow damage are analyzed. The following suggestions are made to improve the life of coiled tubing: select the right material and the right size coiled tubing;Use appropriate measures to prevent premature coiled tubing failure and reduce operating costs.
基金Project(51474237) supported by the National Natural Science Foundation of China
文摘An enhanced leaching of Li fromα-spodumene was carried out using a mixture of hydrofluoric and sulfuric acid(HF/H2SO4)as the medium.Based on the optimized leaching conditions,the leaching kinetics of Li was investigated in an ore/HF/H2SO4 ratio of 1:3:2 g:mL:mL with leaching temperature ranging from 50 to 100°C.The results indicate that the leaching kinetics of Li fitted well with a model based on the shrinking core model.In addition,the leaching rate of Li was controlled by chemical reactions and diffusion through the product layers.The apparent activation energy Ea was calculated to be 32.68 kJ/mol.Solid films were formed because of the generation of insoluble products such as cryolithionite(Na3Li2Al2F12),cryolite(Na3AlF6),calcium fluoride(CaF2),potassium cryolite(K2AlF5),aluminum fluoride(AlF3),and fluorosilicates(Na2SiF6 or KNaSiF6).Furthermore,the effects of the ore/HF ratio and leaching temperature on the leaching behavior of Li,Al and Si were investigated.The results indicate that the ore/HF ratio and leaching temperature could clearly affect the distribution of HF molecules on the leaching of Li,Al and Si,which are important for the selective leaching of Li over Al and Si with this fluorine-based chemical method.
基金supported by National Natural Science Foundation of China (Grant No. 51877086)
文摘In this paper, a two-dimensional axisymmetric fluid model was established to investigate the influence of nitrogen impurity content on the discharge pattern and the relevant discharge characteristics in an atmosphere pressure helium dielectric barrier discharge(DBD). The results indicated that when the nitrogen content was increased from 1 to 100 ppm, the discharge pattern evolved from a concentric-ring pattern into a uniform pattern, and then returned to the concentricring pattern. In this process, the discharge mode at the current peak moment transformed from glow mode into Townsend mode, and then returned to glow mode. Further analyses revealed that with the increase of impurity level, the rate of Penning ionization at the pre-ionization stage increased at first and decreased afterwards, resulting in a similar evolution pattern of seed electron level. This evolution trend was believed to be resulted from the competition between the N2 partial pressure and the consumption rate of metastable species. Moreover, the discharge uniformity was found positively correlated with the spatial uniformity of seed electron density as well as the seed electron level. The reason for this correlation was explained by the reduction of radial electric field strength and the promotion of seed electron uniformity as pre-ionization level increases. The results obtained in this work may help better understand the pattern formation mechanism of atmospheric helium DBD under the variation of N2 impurity level, thereby providing a possible means of regulating the discharge performance in practical application scenarios.
文摘BACKGROUND: Etiologic organism is not frequently isolated despite multiple blood and lfuid cultures during management of pyogenic liver abscess (PLA). Such culture negative pyogen-ic liver abscess (CNPLA) is routinely managed by antibiotics targeted toKlebsiella pneumoniae. In this study, we evaluated the outcomes of such clinical practice. METHODS: All the patients with CNPLA andKlebsiella pneu-moniaePLA (KPPLA) admitted from January 2003 to Decem-ber 2011 were included in the study. A retrospective review of medical records was performed and demographic, clinical and outcome data were collected. RESULTS: A total of 528 patients were treated as CNPLA or KPPLA over the study period. CNPLA presented more com-monly with abdominal pain (P=0.024). KPPLA was more com-mon in older age (P=0.029) and was associated with thrombo-cytopenia (P=0.001), elevated creatinine (P=0.002), bilirubin (P=0.001), alanine aminotransferase (P=0.006) and C-reactive protein level (P=0.036). CNPLA patients tend to have anemia (P=0.015) and smaller abscess (P=0.008). There was no differ-ence in hospital stay (15.7 vs 16.8 days) or mortality (14.0% vs 11.0%). No patients required surgical drainage after initiation of medical therapy. CONCLUSION: Despite demographic and clinical differences between CNPLA and KPPLA, overall outcomes are not different.
基金supported by a grant from the National Science and Technology Major Project of China (2008ZX10002-025& 2008ZX10002-026)
文摘BACKGROUND:Biliary atresia(BA) is a major cause of chronic cholestasis,a fatal disorder in infants.This study was undertaken to evaluate the safety and effectiveness of primary living donor liver transplantation(LDLT) in comparison with the traditional first-line treatment,the Kasai procedure.METHODS:We assessed 28 children with BA at age of less than two years(3-21.3 months) who had undergone LDLT in two hospitals in Southwest China during the period of 2008-2011.Eighteen children who had had primary LDLT were included in a primary LDLT group,and ten children who had undergone the Kasai operation in a pre-Kasai group.All patients were followed up after discharge from the hospital.The records of the BA patients and donors were reviewed.RESULTS:The time of follow-up ranged 12-44.5 months with a median of 31 months.The 30-day and 1-year survival rates were 85.7% and 78.6%,respectively.There was no significant difference in the 30-day or 1-year survival between the two groups(83.3% vs 90% and 77.8% vs 80%,P】0.05).The main cause of death was hepatic artery thrombosis.There were more patients with complications who required intensive medical care or re-operation in the pre-Kasai group(8,80%) than in the primary LDLT group(9,50%)(P=0.226).But no significant differences were observed in operating time(9.3 vs 8.9 hours,P=0.77),intraoperative blood loss(208.6 vs 197.0 mL,P=0.84) and blood transfusion(105.6 vs 100.0 mL,P=0.91) between the two groups.The durations of ICU and hospital stay in the primary LDLT group and pre-Kasai group were 180.4 vs 157.7 hours(P=0.18) and 27 vs 29 days(P=0.29),respectively.CONCLUSIONS:Primary LDLT is a safe and efficient management for young pediatric patients with BA.Compared with the outcome of LDLT for patients receiving a previous Kasai operation,a similar survival rate and a low rate of re-operation and intensive medical care for patients with BA can be obtained.
文摘Timataxel(13-(N-Boc-3-i-butylisoserinoyl-4,10-β-diacetoxy-2-α-benzoyloxy-5-β-20-epoxy-1,13-α-dihydroxy-9-oxo-19-norcyclopropa[g]tax-11-ene)), used to be called TM-2, is a novel semi-synthetic promising candidate for cancer treatment. However the preformulation study showed that TM-2 was insoluble and chemically instable in water, which would limit its application. This study aimed at the preparation of Timataxel lipid microspheres(TM-2 LMs)and investigated the difference between TM-2 LMs and TM-2 solution in pharmacokinetics. In this work, the final formulation was as follows: 0.10%(w/v) TM-2;10.00%(w/v) oil phase(long chain triglyceride:media chain triglyceride = 2.50%:7.50%);1.40%(w/v) phospholipid;0.02%(w/v) NaH2 PO4;2.25%(w/v) glycerin and water to a total volume of 100 ml.The particle size distribution, content and entrapment efficacy were 205.0 ± 43.3 nm, 101.00% and 99.12%, respectively. TM-2 LMs were stable during storage at 25 °C for 3 months, even under the condition of 60 °C and 4500 lx for 10 d. Phosphatidylethanolamine(PE) in phospholipid may contribute to the stability of TM-2 LMs. The pharmacokinetic parameters for TM-2 LMs were as follows: AUC(0-∞) 3663.71 μg/l h and the clearance 2.26 l/h/kg. As for solution, these parameters were 1712.52 μg/l h and 4.77 l/h/kg, respectively. The t1/2 of TM-2 LMs was similar to TM-2 solution. The pharmacokinetic results indicated that the AUC of TM-2 LMs was larger, the clearance was smaller than that of TM-2 solution. In a word, lipid microspheres were a promising drug delivery system for TM-2.
基金supported by the Civil Space Research project (ZH1 data validation: Ionospheric observatory theory)NFSC grant 41574139 and 41874174
文摘The China Seismo-Electromagnetic Satellite, launched into orbit from Jiuquan Satellite Launch Centre on February 2 nd, 2018, is China's first space satellite dedicated to geophysical exporation. The satellite carries eight scientific payloads including high-precision magnetometers to detect electromagnetic changes in space, in particular changes associated with global earthquake disasters. In order to encourage and facilitate use by geophysical scientists of data from the satellite's payloads, this paper introduces the application systems developed for the China Seismo-Electromagnetic Satellite by the Institute of Crustal Dynamics, China Earthquake Administration;these include platform construction, data classification, data storage, data format, and data access and acquisition.
基金supported by the National Natural Science Foundation of China (41404058)
文摘The CSES(China seismic electromagnetic satellite) was launched on February 2, 2018 in a circular polar orbit at an altitude of～507 km. One of the main objectives of CSES is to search for and characterize ionospheric perturbations that can be associated with seismic activities, to better understand the generation mechanism of such perturbations. Its scientific payload can measure a broad frequency range of electromagnetic waves and some important plasma parameters. This paper is a first-hand study of unusual observations recorded by the CSES over seismic regions prior to four earthquakes with M >7.0 since the satellite's launch. CSES detectors measured irregularities near the epicenter of these four earthquakes. It is already clear that data from instruments onboard the CSES will be of significant help in studies of characteristics of ionospheric perturbations related to earthquakes and their generation mechanisms.
