AIM To examine the relationship between serum autotaxin(ATX) concentrations and clinicopathological findings in non-alcoholic fatty liver disease(NAFLD) patients.METHODS One hundred eighty-six NAFLD patients who had u...AIM To examine the relationship between serum autotaxin(ATX) concentrations and clinicopathological findings in non-alcoholic fatty liver disease(NAFLD) patients.METHODS One hundred eighty-six NAFLD patients who had undergone liver biopsy between 2008 and 2017 were retrospectively enrolled.Serum samples were collected at the time of biopsy and ATX was measured by enzyme immunoassays.Sera obtained from 160 healthy,nonobese individuals were used as controls.Histological findings were graded according to an NAFLD scoring system and correlations with serum ATX were calculated by Spearman's test.Diagnostic accuracy was evaluated using the area under the receiver operating characteristic curve(AUC).Cut-off values were identified by the Youden index,and the nearest clinically applicable value to the cutoff was considered the optimal threshold for clinical convenience.RESULTS Serum ATX levels were significantly higher in NAFLD patients than in controls(0.86 mg/L vs 0.76 mg/L,P < 0.001) and correlated significantly with ballooning score and fibrosis stage(r = 0.36,P < 0.001 and r = 0.45,P < 0.001,respectively).Such tendencies were stronger in female patients.There were no remarkable relationships between ATX and serum alanine aminotransferase,lipid profiles,or steatosis scores.The AUC values of ATX for predicting the presence of fibrosis(≥ F1),significant fibrosis(≥ F2),severe fibrosis(≥ F3),and cirrhosis(F4),were all more than 0.70 in respective analyses.CONCLUSION Serum ATX levels may at least partially reflect histological severity in NAFLD.展开更多
Takotsubo cardiomyopathy is characterized by the development of transient left ventricular regional wall motion abnormalities,in the absence of significant coronary artery obstruction. This syndrome usually occurs in ...Takotsubo cardiomyopathy is characterized by the development of transient left ventricular regional wall motion abnormalities,in the absence of significant coronary artery obstruction. This syndrome usually occurs in women and is frequently associated with an intense emotional or physical stress. It usually involves apical segments,but in the recent years atypical forms have been described. Inverted or reverse Takotsubo is a variant in which the basal and midventricular segments are hypokinetic,sparing contractile function of the apex. In this report we describe the case of a 54-year-old woman,with chronic malnutrition,initially admitted because of hypoglycemia and severe electrolyte disturbance due to a refeeding syndrome. Within the next hours she experienced acute cardiac symptoms and developed heart failure with low cardiac output. Electrocardiogram(ECG),elevation of troponin and echocardiographic findings were consistent with inverted Takotsubo cardiomyopathy. To the best of our knowledge,this is the first incidence reported of inverted Takotsubo triggered by refeeding syndrome.展开更多
A ballooning mode equation for tokamak plasma, with the toroidicity and the Shafranov shift effects included, is derived for a shift circular flux tokamak configuration. Using this equation, the stability of the plasm...A ballooning mode equation for tokamak plasma, with the toroidicity and the Shafranov shift effects included, is derived for a shift circular flux tokamak configuration. Using this equation, the stability of the plasma configuration with an internal transport barrier (ITB) against the high n (the toroidal mode number) ideal magnetohydrodynamic (MHD) ballooning mode is analysed. It is shown that both the toroidicity and the Shaftanov shift effects are stabilizing. In the ITB region, these effects give rise to a low shear stable channel between the first and the second stability regions. Out of the ITB region towards the plasma edge, the stabilizing effect of the Shaftanov shift causes the unstable zone to be significantly narrowed.展开更多
The linear analysis of the influence of diamagnetic effect and toroidal rotation at the edge of tokamak plasmas with BOUT++ is discussed in this paper. This analysis is done by solving the dispersion relation, which i...The linear analysis of the influence of diamagnetic effect and toroidal rotation at the edge of tokamak plasmas with BOUT++ is discussed in this paper. This analysis is done by solving the dispersion relation, which is calculated through the numerical integration of the terms with different physics. This method is able to reveal the contributions of the different terms to the total growth rate. The diamagnetic effect stabilizes the ideal ballooning modes through inhibiting the contribution of curvature. The toroidal rotation effect is also able to suppress the curvaturedriving term, and the stronger shearing rate leads to a stronger stabilization effect. In addition,through linear analysis using the energy form, the curvature-driving term provides the free energy absorbed by the line-bending term, diamagnetic term and convective term.展开更多
It is shown that a steepening of the radial plasma pressure profile leads to a decrease in the critical value of beta,above which,small-scale balloon-type perturbations in a mirror trap become unstable.This may mean t...It is shown that a steepening of the radial plasma pressure profile leads to a decrease in the critical value of beta,above which,small-scale balloon-type perturbations in a mirror trap become unstable.This may mean that small-scale ballooning instability leads to a smoothing of the radial plasma profile.The critical beta values for the real magnetic field of the gas-dynamic trap and various plasma pressure radial profiles was also calculated.For a plasma with a parabolic profile critical beta is evaluated at the level of 0.72.A previous theoretical prediction for this trap was almost two times lower than maximal beta 0.6 achieved experimentally.展开更多
In the present paper,we first derive the eigenmode equation of the ideal ballooning mode in tokamak plasmas using a gyrokinetic equation.It is shown that the gyrokinetic eigenmode equation can be reduced to the magnet...In the present paper,we first derive the eigenmode equation of the ideal ballooning mode in tokamak plasmas using a gyrokinetic equation.It is shown that the gyrokinetic eigenmode equation can be reduced to the magnetohydrodynamic(MHD) form in the long wavelength limit when kinetic effects are ignored.Then,the global gyrokinetic toroidal code(GTC) is applied for simulations of the edge-localized ideal ballooning modes.The obtained mode structures are compared with the results of ideal MHD simulations.The observed scaling of the linear growth rate with the toroidal mode number is consistent with the ideal MHD theory.The simulation results verify the GTC capability of simulating MHD processes in toroidal plasmas.展开更多
Improved confinement of tokamak plasma with central negative shear is checked against the resistive ballooning mode. In the negative shear regime, the plasma is always unstable for purely growing resistive ballooning ...Improved confinement of tokamak plasma with central negative shear is checked against the resistive ballooning mode. In the negative shear regime, the plasma is always unstable for purely growing resistive ballooning mode. For a simplest tokamak equilibrium model, the s-α model, characteristics of this kind of instability are fully clarified by numerically solving the high n resistive magnetohydrodynamic ballooning eigen-equation. Dependences of the growth rate on the resistivity, the absolute shear value, the pressure gradient are scanned in detail. It is found that the growth rate is a monotonically increasing function of a while it is not sensitive to the changes of the shear s, the initial phase θ0 and the resistivity parameter εR.展开更多
In this paper, the effect of finite Larmor radius (FLR) on high n ballooning modes is studied on the basis of FLR magnetohydrodynamic (FLR-MHD) theory. A linear FLR ballooning mode equation is derived in an 's^--...In this paper, the effect of finite Larmor radius (FLR) on high n ballooning modes is studied on the basis of FLR magnetohydrodynamic (FLR-MHD) theory. A linear FLR ballooning mode equation is derived in an 's^-- α' type equilibrium of circular-flux-surfaces, which is reduced to the ideal ballooning mode equation when the FLR effect is neglected. The present model reproduces some basic features of FLR effects on ballooning mode obtained previously by kinetic ballooning mode theories. That is, the FLR introduces a real frequency into ballooning mode and has a stabilising effect on ballooning modes (e.g., in the case of high magnetic shear s^- ≥ 0.8). In particular, some new properties of FLR effects on ballooning mode are discovered in the present research. Here it is found that in a high magnetic shear region (s^- ≥ 0.8) the critical pressure gradient (αc,FLR) of ballooning mode is larger than the ideal one (αc,IMHD) and becomes larger and larger with the increase of FLR parameter b0. However, in a low magnetic shear region, the FLR ballooning mode is more unstable than the ideal one, and the αc,FLR is much lower than the αc,IMHD. Moreover, the present results indicate that there exist some new weaker instabilities near the second stability boundary (obtained from ideal MHD theory), which means that the second stable region becomes narrow.展开更多
Apical ballooning syndrome (Takotsubo cardiomyopathy) is an increasingly recognized form of acute systolic dysfunction which is usually reversible. It typically occurs in post-menopausal women following a major psycho...Apical ballooning syndrome (Takotsubo cardiomyopathy) is an increasingly recognized form of acute systolic dysfunction which is usually reversible. It typically occurs in post-menopausal women following a major psychological stressor. We conducted a single center, retrospective analysis of all hospitalized patients from 2001-2012 and found 104 patients who met the diagnostic criteria for apical ballooning. In this current largest series of its kind, 83% of the patients were women. Among both men and women, an antecedent stressor was not always identified. The exact pathophysiologic mechanism resulting in apical ballooning remains poorly understood. These findings challenge the paradigm that catecholamine cardiotoxicity in the setting of relative estrogen deficiency results in the cardiomyopathy.展开更多
Aims: Left ventricular apical ballooning syndrome (LVABS) is a clinical condition of unknown etiology, characterized by acute onset of atypical apical wall motion and absence of coronary artery disease. Gadolinium-enh...Aims: Left ventricular apical ballooning syndrome (LVABS) is a clinical condition of unknown etiology, characterized by acute onset of atypical apical wall motion and absence of coronary artery disease. Gadolinium-enhanced cardiac magnetic resonance imaging (Gd-MRI) may be used to identify patients with myocarditis. Using cardiac MRI, we evaluated whether acute myocarditis may be an etiology that underlies LVABS. Methods and Results: Consecutive patients who presented with LVABS during a three-year period were included. Demographic data was recorded and echocardiography, coronary angiography, and hemodynamic assessment performed. Gd-MRI was performed in all patients. The study was deemed consistent with myocarditis when global myocardial to skeletal muscle enhancement ratio was ≥3.5. Regional Gd-MRI analysis was also performed. Patients (n = 11) were female (100%) and of mean age 72 years (72 ± 11). Preceding febrile illness occurred in 4 (36.3%) and leukocytosis in 6 (54.4%) patients. Initial mean left ventricular ejection fraction (41% ± 12%) improved (70.2% ± 8%) upon follow-up (39 ± 43 days). Global MRI analysis was positive in 5/11 (45.5%) (mean relative enhancement ratio 4.8 ± 1.4). Regional MRI analysis was positive in 4/6 further patients (overall: 9/11 (82%)). Conclusions: Gadolinium enhanced MRI imaging in LVABS implicates myocarditis as a possible etiology. Regional MRI analysis adds sensitivity to global cardiac MRI evaluation.展开更多
Transient apical ballooning syndrome(Tako-Tsubo syndrome or ampulla cardiomyopathy) occurs predominantly in women over 60 years of age with a history of recent physical or psychological stress. We present a case of ...Transient apical ballooning syndrome(Tako-Tsubo syndrome or ampulla cardiomyopathy) occurs predominantly in women over 60 years of age with a history of recent physical or psychological stress. We present a case of a male patient with reversible transient apical ballooning syndrome with significant coronary lesions and other ECG changes that did not explain the clinical symptoms.展开更多
Mid ventricular ballooning syndrome (MBS) was diagnosed in a 55-year-old woman who was admitted to emergency room due to acute chest pain. The trigger for the chest pain was reported as “bad dream” about her husband...Mid ventricular ballooning syndrome (MBS) was diagnosed in a 55-year-old woman who was admitted to emergency room due to acute chest pain. The trigger for the chest pain was reported as “bad dream” about her husband. MBS, a variant of Tako-tsubo Cardiomyopathy is more common in postmenopausal women and the triggers have been linked to stress involving the husband. Sudden catecholamine surge during nightmare augmented by estrogen deficiency in postmenopausal women may be the underlying mechanism. There are many unanswered questions related to the etiology of MBS. With supportive treatment, prognosis is excellent.展开更多
Internal transport barriers (ITBs) are phenomena associated with improved confinement mode of tokamak plasmas. Within the region where the ITB locates, the plasma pressure has a large gradient while the magnetic she...Internal transport barriers (ITBs) are phenomena associated with improved confinement mode of tokamak plasmas. Within the region where the ITB locates, the plasma pressure has a large gradient while the magnetic shear s has a minimum so that within and near the ITB, the absolute value of the shear is very low. Physics involved is plentiful, from the macroscopic ( MHD ) stability, to the suppression of microscopic instabilities thought to be responsible for anomalous transport. The treatment of very low shear also poses some theoretical difficulties.展开更多
AIM: To clarify the relationship between autophagy and lipotoxicity-induced apoptosis, which is termed "lipoapoptosis," in non-alcoholic steatohepatitis. METHODS: Male C57BL/6J mice were fed a high-fat diet(...AIM: To clarify the relationship between autophagy and lipotoxicity-induced apoptosis, which is termed "lipoapoptosis," in non-alcoholic steatohepatitis. METHODS: Male C57BL/6J mice were fed a high-fat diet(HFD) for 12 wk, after which the liver histology and expression of proteins such as p62 or LC3 were evaluated. Alpha mouse liver 12(AML12) cells treated with palmitate(PA) were used as an in vitro model. RESULTS: LC3-Ⅱ, p62, and Run domain Beclin-1 interacting and cysteine-rich containing(Rubicon) proteins increased in both the HFD mice and in AML12 cells in response to PA treatment. Rubicon expression was decreased upon c-Jun N-terminal kinase(JNK) inhibition at both the m RNA and the protein level in AML12 cells. Rubicon knockdown in AML12 cells with PA decreased the protein levels of both LC3-Ⅱ and p62. Rubicon expression peaked at 4 h of PA treatment in AML12, and then decreased. Treatment with caspase-9 inhibitor ameliorated the decrease in Rubicon protein expression at 10 h of PA and resulted in enlarged AML12 cells under PA treatment. The enlargement of AML12 cells by PA with caspase-9 inhibition was canceled by Rubicon knockdown.CONCLUSION: The JNK-Rubicon axis enhanced lipoapoptosis, and caspase-9 inhibition and Rubicon had effects that were cytologically similar to hepatocyte ballooning. As ballooned hepatocytes secrete fibrogenic signals and thus might promote fibrosis in the liver, the inhibition of hepatocyte ballooning might provide antifibrosis in the NASH liver.展开更多
We examined the global biogeography of the Scytodes thoracica group of spitting spiders based on 23 years of sampling at the species level(61 species in the thoracica group and 84 species of Scytodes)using DNA data fr...We examined the global biogeography of the Scytodes thoracica group of spitting spiders based on 23 years of sampling at the species level(61 species in the thoracica group and 84 species of Scytodes)using DNA data from six loci.Our results indicated that the thoracica group initially dispersed from Southeast Asia to East Africa between 46.5 and 33.0 million years ago,and dispersal events intensified between Southeast/South Asia and East/South Africa from the early to late Miocene.The timing of these events indicates that Asian-African faunal exchange of the thoracica group was driven by the Indian monsoon,and the pattern of dispersal suggests that colonialization took root when the Indian monsoon shifted from a North-South direction to an East-West direction from the middle Eocene.展开更多
The effects of equilibrium toroidal rotation during edge-localized mode(ELM)mitigated by resonant magnetic perturbation(RMP)are studied with the experimental equilibria of the EAST tokamak based on the four-field mode...The effects of equilibrium toroidal rotation during edge-localized mode(ELM)mitigated by resonant magnetic perturbation(RMP)are studied with the experimental equilibria of the EAST tokamak based on the four-field model in the BOUT++code.As the two main parameters to determine the toroidal rotation profiles,the rotation shear and magnitudes were separately scanned to investigate their roles in the impact of RMPs on peeling-ballooning(P-B)modes.On one hand,the results show that strong toroidal rotation shear is favorable for the enhancement of the self-generated E×B shearing rate<ω_(E×B)>with RMPs,leading to significant ELM mitigation with RMP in the stronger toroidal rotation shear region.On the other hand,toroidal rotation magnitudes may affect ELM mitigation by changing the penetration of the RMPs,more precisely the resonant components.RMPs can lead to a reduction in the pedestal energy loss by enhancing the multimode coupling in the turbulence transport phase.The shielding effects on RMPs increase with the toroidal rotation magnitude,leading to the enhancement of the multimode coupling with RMPs to be significantly weakened.Hence,the reduction in pedestal energy loss by RMPs decreased with the rotation magnitude.In brief,the results show that toroidal rotation plays a dual role in ELM mitigation with RMP by changing the shielding effects of plasma by rotation magnitude and affecting<ω_(E×B)>by rotation shear.In the high toroidal rotation region,toroidal rotation shear is usually strong and hence plays a dominant role in the influence of RMP on P-B modes,whereas in the low rotation region,toroidal rotation shear is weak and has negligible impact on P-B modes,and the rotation magnitude plays a dominant role in the influence of RMPs on the P-B modes by changing the field penetration.Therefore,the dual role of toroidal rotation leads to stronger ELM mitigation with RMP,which may be achieved both in the low toroidal rotation region and the relatively high rotation region that has strong rotational shear.展开更多
BACKGROUND Nonalcoholic fatty liver disease(NAFLD)is one of the most common chronic liver diseases in children and adolescents.NAFLD ranges in severity from isolated hepatic steatosis to nonalcoholic steatohepatitis(N...BACKGROUND Nonalcoholic fatty liver disease(NAFLD)is one of the most common chronic liver diseases in children and adolescents.NAFLD ranges in severity from isolated hepatic steatosis to nonalcoholic steatohepatitis(NASH),wherein hepatocellular inflammation and/or fibrosis coexist with steatosis.Circulating microRNA(miRNA)levels have been suggested to be altered in NAFLD,but the extent to which miRNA are related to NAFLD features remains unknown.This analysis tested the hypothesis that plasma miRNAs are significantly associated with histological features of NAFLD in adolescents.AIM To investigate the relationship between plasma miRNA expression and NAFLD features among adolescents with NAFLD.METHODS This study included 81 adolescents diagnosed with NAFLD and 54 adolescents without NAFLD from the Teen-Longitudinal Assessment of Bariatric Surgery study.Intra-operative core liver biopsies were collected from participants and used to characterize histological features of NAFLD.Plasma samples were collected during surgery for miRNA profiling.A total of 843 plasma miRNAs were profiled using the HTG EdgeSeq platform.We examined associations of plasma miRNAs and NAFLD features using logistic regression after adjusting for age,sex,race,and other key covariates.Ingenuity Pathways Analysis was used to identify biological functions of miRNAs that were associated with multiple histological features of NAFLD.RESULTS We identified 16 upregulated plasma miRNAs,including miR-193a-5p and miR-193b-5p,and 22 downregulated plasma miRNAs,including miR-1282 and miR-6734-5p,in adolescents with NAFLD.Moreover,52,16,15,and 9 plasma miRNAs were associated with NASH,fibrosis,ballooning degeneration,and lobular inflammation,respectively.Collectively,16 miRNAs were associated with two or more histological features of NAFLD.Among those miRNAs,miR-411-5p was downregulated in NASH,ballooning,and fibrosis,while miR-122-5p,miR-1343-5p,miR-193a-5p,miR-193b-5p,and miR-7845-5p were consistently and positively associated with all histological features of NAFLD.Pathway analysis revealed that most common pathways of miRNAs associated with multiple NAFLD features have been associated with tumor progression,while we also identified linkages between miR-122-5p and hepatitis C virus and between miR-199b-5p and chronic hepatitis B.CONCLUSION Plasma miRNAs were associated with NAFLD features in adolescent with severe obesity.Larger studies with more heterogeneous NAFLD phenotypes are needed to evaluate miRNAs as potential biomarkers of NAFLD.展开更多
Percutaneous coronary interventions have progressed through the era of plain balloon dilation, bare-metal stent insertion to drug-eluting stent treatment, which has significantly reduced the acute occlusion and resten...Percutaneous coronary interventions have progressed through the era of plain balloon dilation, bare-metal stent insertion to drug-eluting stent treatment, which has significantly reduced the acute occlusion and restenosis rates of target vessels and improved patient prognosis, making drug-eluting stents the mainstream interventional treatment for coronary artery disease. In recent years, drug-coated balloons(DCBs) have become a new treatment strategy for coronary artery disease, and the drugs used in the coating and the coating technology have progressed in the past years. Without permanent implant, a DCB delivers antiproliferative drugs rapidly and uniformly into the vessel wall via the excipient during a single balloon dilation. Many evidence suggests that DCB angioplasty is an effective measure for dealing with in-stent restenosis and de novo lesions in small coronary vessels.As more clinical studies are published, new evidence is emerging for the use of DCB angioplasty in a wide range of coronary diseases, and the indications are expanding internationally. Based on the latest research from China and elsewhere, the Expert Writing Committee of the Chinese Expert Consensus on Clinical Applications of Drug-Coated Balloon has updated the previous DCB consensus after evidence-based discussions and meetings in terms of adequate preparation of in-stent restenosis lesions, expansion of the indications for coronary de novo lesions, and precise guidance of DCB treatment by intravascular imaging and functional evaluation.展开更多
As multi-core processors become the de-facto configuration in modern computers, the adoption of SMP Virtual Machines(VMs) has been increasing, allowing for more efficient use of computing resources. However,because ...As multi-core processors become the de-facto configuration in modern computers, the adoption of SMP Virtual Machines(VMs) has been increasing, allowing for more efficient use of computing resources. However,because of existence of schedulers in both the hypervisor and the guest VMs, this creates a new research problem,viz., double scheduling. Although double scheduling may cause many issues including lock-holder preemption,v CPU stacking, CPU fragmentation, and priority inversion, prior approaches have either introduced new problems and/or addressed the problem incompletely. In this paper, we describe the design and implementation of Flex Core,a new scheduling scheme using v CPU ballooning, which dynamically adjusts the number of v CPUs of a VM at runtime. This essentially eliminates unnecessary scheduling in the hypervisor layer, and thus, boosts performance significantly. An evaluation using a complete KVM-based implementation shows that the average performance improvement for PARSEC applications on a 12-core Intel machine is approximately 52.9%, ranging from 35.4% to79.6%.展开更多
文摘AIM To examine the relationship between serum autotaxin(ATX) concentrations and clinicopathological findings in non-alcoholic fatty liver disease(NAFLD) patients.METHODS One hundred eighty-six NAFLD patients who had undergone liver biopsy between 2008 and 2017 were retrospectively enrolled.Serum samples were collected at the time of biopsy and ATX was measured by enzyme immunoassays.Sera obtained from 160 healthy,nonobese individuals were used as controls.Histological findings were graded according to an NAFLD scoring system and correlations with serum ATX were calculated by Spearman's test.Diagnostic accuracy was evaluated using the area under the receiver operating characteristic curve(AUC).Cut-off values were identified by the Youden index,and the nearest clinically applicable value to the cutoff was considered the optimal threshold for clinical convenience.RESULTS Serum ATX levels were significantly higher in NAFLD patients than in controls(0.86 mg/L vs 0.76 mg/L,P < 0.001) and correlated significantly with ballooning score and fibrosis stage(r = 0.36,P < 0.001 and r = 0.45,P < 0.001,respectively).Such tendencies were stronger in female patients.There were no remarkable relationships between ATX and serum alanine aminotransferase,lipid profiles,or steatosis scores.The AUC values of ATX for predicting the presence of fibrosis(≥ F1),significant fibrosis(≥ F2),severe fibrosis(≥ F3),and cirrhosis(F4),were all more than 0.70 in respective analyses.CONCLUSION Serum ATX levels may at least partially reflect histological severity in NAFLD.
基金Supported by Hospital Universitario Fundación Alcorcón,Madrid(Spain)
文摘Takotsubo cardiomyopathy is characterized by the development of transient left ventricular regional wall motion abnormalities,in the absence of significant coronary artery obstruction. This syndrome usually occurs in women and is frequently associated with an intense emotional or physical stress. It usually involves apical segments,but in the recent years atypical forms have been described. Inverted or reverse Takotsubo is a variant in which the basal and midventricular segments are hypokinetic,sparing contractile function of the apex. In this report we describe the case of a 54-year-old woman,with chronic malnutrition,initially admitted because of hypoglycemia and severe electrolyte disturbance due to a refeeding syndrome. Within the next hours she experienced acute cardiac symptoms and developed heart failure with low cardiac output. Electrocardiogram(ECG),elevation of troponin and echocardiographic findings were consistent with inverted Takotsubo cardiomyopathy. To the best of our knowledge,this is the first incidence reported of inverted Takotsubo triggered by refeeding syndrome.
基金Project supported by the National Natural Science Foundation of China (Grant No 10375018).
文摘A ballooning mode equation for tokamak plasma, with the toroidicity and the Shafranov shift effects included, is derived for a shift circular flux tokamak configuration. Using this equation, the stability of the plasma configuration with an internal transport barrier (ITB) against the high n (the toroidal mode number) ideal magnetohydrodynamic (MHD) ballooning mode is analysed. It is shown that both the toroidicity and the Shaftanov shift effects are stabilizing. In the ITB region, these effects give rise to a low shear stable channel between the first and the second stability regions. Out of the ITB region towards the plasma edge, the stabilizing effect of the Shaftanov shift causes the unstable zone to be significantly narrowed.
基金supported by program of Fusion Reactor Physics and Digital Tokamak with the CAS ‘OneThree-Five’ Strategic Planningthe JSPS-NRF-NSFC A3 Foresight Program in the field of Plasma Physics (NSFC: No. 11261140328 and NRF: No. z012K2A2A6000443)+1 种基金supported by National Natural Science Foundation of China under Contract Nos. 11405215, 11505236 and 11675217the National Magnetic Confinement Fusion Science Program of China under Contract Nos. 2015GB101003, 2014GB106001 and 2013GB111002
文摘The linear analysis of the influence of diamagnetic effect and toroidal rotation at the edge of tokamak plasmas with BOUT++ is discussed in this paper. This analysis is done by solving the dispersion relation, which is calculated through the numerical integration of the terms with different physics. This method is able to reveal the contributions of the different terms to the total growth rate. The diamagnetic effect stabilizes the ideal ballooning modes through inhibiting the contribution of curvature. The toroidal rotation effect is also able to suppress the curvaturedriving term, and the stronger shearing rate leads to a stronger stabilization effect. In addition,through linear analysis using the energy form, the curvature-driving term provides the free energy absorbed by the line-bending term, diamagnetic term and convective term.
基金financially supported by the Ministry of Education and Science of the Russian Federationsupported by Chinese Academy of Sciences Presidents International Fellowship Initiative(PIFI)under Grant No.2022VMA0007Chinese Academy of Sciences International Partnership Program under Grant No.116134KYSB20200001。
文摘It is shown that a steepening of the radial plasma pressure profile leads to a decrease in the critical value of beta,above which,small-scale balloon-type perturbations in a mirror trap become unstable.This may mean that small-scale ballooning instability leads to a smoothing of the radial plasma profile.The critical beta values for the real magnetic field of the gas-dynamic trap and various plasma pressure radial profiles was also calculated.For a plasma with a parabolic profile critical beta is evaluated at the level of 0.72.A previous theoretical prediction for this trap was almost two times lower than maximal beta 0.6 achieved experimentally.
基金supported by U.S.Department of Energy(DOE) SciDAC GSEP Center and National Special Research Program of China for ITER
文摘In the present paper,we first derive the eigenmode equation of the ideal ballooning mode in tokamak plasmas using a gyrokinetic equation.It is shown that the gyrokinetic eigenmode equation can be reduced to the magnetohydrodynamic(MHD) form in the long wavelength limit when kinetic effects are ignored.Then,the global gyrokinetic toroidal code(GTC) is applied for simulations of the edge-localized ideal ballooning modes.The obtained mode structures are compared with the results of ideal MHD simulations.The observed scaling of the linear growth rate with the toroidal mode number is consistent with the ideal MHD theory.The simulation results verify the GTC capability of simulating MHD processes in toroidal plasmas.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10375018 and 10575032).
文摘Improved confinement of tokamak plasma with central negative shear is checked against the resistive ballooning mode. In the negative shear regime, the plasma is always unstable for purely growing resistive ballooning mode. For a simplest tokamak equilibrium model, the s-α model, characteristics of this kind of instability are fully clarified by numerically solving the high n resistive magnetohydrodynamic ballooning eigen-equation. Dependences of the growth rate on the resistivity, the absolute shear value, the pressure gradient are scanned in detail. It is found that the growth rate is a monotonically increasing function of a while it is not sensitive to the changes of the shear s, the initial phase θ0 and the resistivity parameter εR.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10775040 and 10775043)
文摘In this paper, the effect of finite Larmor radius (FLR) on high n ballooning modes is studied on the basis of FLR magnetohydrodynamic (FLR-MHD) theory. A linear FLR ballooning mode equation is derived in an 's^-- α' type equilibrium of circular-flux-surfaces, which is reduced to the ideal ballooning mode equation when the FLR effect is neglected. The present model reproduces some basic features of FLR effects on ballooning mode obtained previously by kinetic ballooning mode theories. That is, the FLR introduces a real frequency into ballooning mode and has a stabilising effect on ballooning modes (e.g., in the case of high magnetic shear s^- ≥ 0.8). In particular, some new properties of FLR effects on ballooning mode are discovered in the present research. Here it is found that in a high magnetic shear region (s^- ≥ 0.8) the critical pressure gradient (αc,FLR) of ballooning mode is larger than the ideal one (αc,IMHD) and becomes larger and larger with the increase of FLR parameter b0. However, in a low magnetic shear region, the FLR ballooning mode is more unstable than the ideal one, and the αc,FLR is much lower than the αc,IMHD. Moreover, the present results indicate that there exist some new weaker instabilities near the second stability boundary (obtained from ideal MHD theory), which means that the second stable region becomes narrow.
文摘Apical ballooning syndrome (Takotsubo cardiomyopathy) is an increasingly recognized form of acute systolic dysfunction which is usually reversible. It typically occurs in post-menopausal women following a major psychological stressor. We conducted a single center, retrospective analysis of all hospitalized patients from 2001-2012 and found 104 patients who met the diagnostic criteria for apical ballooning. In this current largest series of its kind, 83% of the patients were women. Among both men and women, an antecedent stressor was not always identified. The exact pathophysiologic mechanism resulting in apical ballooning remains poorly understood. These findings challenge the paradigm that catecholamine cardiotoxicity in the setting of relative estrogen deficiency results in the cardiomyopathy.
文摘Aims: Left ventricular apical ballooning syndrome (LVABS) is a clinical condition of unknown etiology, characterized by acute onset of atypical apical wall motion and absence of coronary artery disease. Gadolinium-enhanced cardiac magnetic resonance imaging (Gd-MRI) may be used to identify patients with myocarditis. Using cardiac MRI, we evaluated whether acute myocarditis may be an etiology that underlies LVABS. Methods and Results: Consecutive patients who presented with LVABS during a three-year period were included. Demographic data was recorded and echocardiography, coronary angiography, and hemodynamic assessment performed. Gd-MRI was performed in all patients. The study was deemed consistent with myocarditis when global myocardial to skeletal muscle enhancement ratio was ≥3.5. Regional Gd-MRI analysis was also performed. Patients (n = 11) were female (100%) and of mean age 72 years (72 ± 11). Preceding febrile illness occurred in 4 (36.3%) and leukocytosis in 6 (54.4%) patients. Initial mean left ventricular ejection fraction (41% ± 12%) improved (70.2% ± 8%) upon follow-up (39 ± 43 days). Global MRI analysis was positive in 5/11 (45.5%) (mean relative enhancement ratio 4.8 ± 1.4). Regional MRI analysis was positive in 4/6 further patients (overall: 9/11 (82%)). Conclusions: Gadolinium enhanced MRI imaging in LVABS implicates myocarditis as a possible etiology. Regional MRI analysis adds sensitivity to global cardiac MRI evaluation.
文摘Transient apical ballooning syndrome(Tako-Tsubo syndrome or ampulla cardiomyopathy) occurs predominantly in women over 60 years of age with a history of recent physical or psychological stress. We present a case of a male patient with reversible transient apical ballooning syndrome with significant coronary lesions and other ECG changes that did not explain the clinical symptoms.
文摘Mid ventricular ballooning syndrome (MBS) was diagnosed in a 55-year-old woman who was admitted to emergency room due to acute chest pain. The trigger for the chest pain was reported as “bad dream” about her husband. MBS, a variant of Tako-tsubo Cardiomyopathy is more common in postmenopausal women and the triggers have been linked to stress involving the husband. Sudden catecholamine surge during nightmare augmented by estrogen deficiency in postmenopausal women may be the underlying mechanism. There are many unanswered questions related to the etiology of MBS. With supportive treatment, prognosis is excellent.
基金Supported by the National Natural Science Foundation of China ( 10375018 )
文摘Internal transport barriers (ITBs) are phenomena associated with improved confinement mode of tokamak plasmas. Within the region where the ITB locates, the plasma pressure has a large gradient while the magnetic shear s has a minimum so that within and near the ITB, the absolute value of the shear is very low. Physics involved is plentiful, from the macroscopic ( MHD ) stability, to the suppression of microscopic instabilities thought to be responsible for anomalous transport. The treatment of very low shear also poses some theoretical difficulties.
文摘AIM: To clarify the relationship between autophagy and lipotoxicity-induced apoptosis, which is termed "lipoapoptosis," in non-alcoholic steatohepatitis. METHODS: Male C57BL/6J mice were fed a high-fat diet(HFD) for 12 wk, after which the liver histology and expression of proteins such as p62 or LC3 were evaluated. Alpha mouse liver 12(AML12) cells treated with palmitate(PA) were used as an in vitro model. RESULTS: LC3-Ⅱ, p62, and Run domain Beclin-1 interacting and cysteine-rich containing(Rubicon) proteins increased in both the HFD mice and in AML12 cells in response to PA treatment. Rubicon expression was decreased upon c-Jun N-terminal kinase(JNK) inhibition at both the m RNA and the protein level in AML12 cells. Rubicon knockdown in AML12 cells with PA decreased the protein levels of both LC3-Ⅱ and p62. Rubicon expression peaked at 4 h of PA treatment in AML12, and then decreased. Treatment with caspase-9 inhibitor ameliorated the decrease in Rubicon protein expression at 10 h of PA and resulted in enlarged AML12 cells under PA treatment. The enlargement of AML12 cells by PA with caspase-9 inhibition was canceled by Rubicon knockdown.CONCLUSION: The JNK-Rubicon axis enhanced lipoapoptosis, and caspase-9 inhibition and Rubicon had effects that were cytologically similar to hepatocyte ballooning. As ballooned hepatocytes secrete fibrogenic signals and thus might promote fibrosis in the liver, the inhibition of hepatocyte ballooning might provide antifibrosis in the NASH liver.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences to S.Q.L.(XDB31000000)National Natural Sciences Foundation of China to Y.F.L.(NSFC-31860602,32170463,31660611)。
文摘We examined the global biogeography of the Scytodes thoracica group of spitting spiders based on 23 years of sampling at the species level(61 species in the thoracica group and 84 species of Scytodes)using DNA data from six loci.Our results indicated that the thoracica group initially dispersed from Southeast Asia to East Africa between 46.5 and 33.0 million years ago,and dispersal events intensified between Southeast/South Asia and East/South Africa from the early to late Miocene.The timing of these events indicates that Asian-African faunal exchange of the thoracica group was driven by the Indian monsoon,and the pattern of dispersal suggests that colonialization took root when the Indian monsoon shifted from a North-South direction to an East-West direction from the middle Eocene.
基金supported by the National MCF Energy R&D Program of China(Nos.2019YFE03090400 and 2019YFE03030004)National Natural Science Foundation of China(Nos.12375222 and 11775154)National Key R&D Program of China(Nos.2017YFE0301203 and 2017YFE0301101)。
文摘The effects of equilibrium toroidal rotation during edge-localized mode(ELM)mitigated by resonant magnetic perturbation(RMP)are studied with the experimental equilibria of the EAST tokamak based on the four-field model in the BOUT++code.As the two main parameters to determine the toroidal rotation profiles,the rotation shear and magnitudes were separately scanned to investigate their roles in the impact of RMPs on peeling-ballooning(P-B)modes.On one hand,the results show that strong toroidal rotation shear is favorable for the enhancement of the self-generated E×B shearing rate<ω_(E×B)>with RMPs,leading to significant ELM mitigation with RMP in the stronger toroidal rotation shear region.On the other hand,toroidal rotation magnitudes may affect ELM mitigation by changing the penetration of the RMPs,more precisely the resonant components.RMPs can lead to a reduction in the pedestal energy loss by enhancing the multimode coupling in the turbulence transport phase.The shielding effects on RMPs increase with the toroidal rotation magnitude,leading to the enhancement of the multimode coupling with RMPs to be significantly weakened.Hence,the reduction in pedestal energy loss by RMPs decreased with the rotation magnitude.In brief,the results show that toroidal rotation plays a dual role in ELM mitigation with RMP by changing the shielding effects of plasma by rotation magnitude and affecting<ω_(E×B)>by rotation shear.In the high toroidal rotation region,toroidal rotation shear is usually strong and hence plays a dominant role in the influence of RMP on P-B modes,whereas in the low rotation region,toroidal rotation shear is weak and has negligible impact on P-B modes,and the rotation magnitude plays a dominant role in the influence of RMPs on the P-B modes by changing the field penetration.Therefore,the dual role of toroidal rotation leads to stronger ELM mitigation with RMP,which may be achieved both in the low toroidal rotation region and the relatively high rotation region that has strong rotational shear.
基金Supported by National Institute of Environmental Health,No.R01ES030691No.R01ES030364,No.R01ES029944,No.U01HG013288,No.T32-ES013678,No.P30ES007048,No.U2CES030859,No.R01ES032831,No.R01ES033688,No.P30ES023515,and No.P2CES033433+8 种基金National Human Genome Research Institute and National Institute of Environmental Health,No.U01HG013288California Environmental Protection Agency,No.20-E0017National Cancer Institute and National Institute of Environmental Health,No.P01CA196569Ministry of Science and Innovation and State Research Agency,No.CEX2018-000806-SEuropean Union(“NextGenerationEU/PRTR”),No.IJC2020-043630-IEuropean Union’s Horizon Europe Research And Innovation Programme Under the Marie Skłodowska-Curie Actions Postdoctoral Fellowships,No.101059245United States Department of Agriculture,No.6250-51000-053National Institutes of Health,No.R01DK128117-01A1The Teen-LABS Consortium:National Institute of Diabetes and Digestive and Kidney Diseases,No.UM1DK072493 and No.UM1DK095710.
文摘BACKGROUND Nonalcoholic fatty liver disease(NAFLD)is one of the most common chronic liver diseases in children and adolescents.NAFLD ranges in severity from isolated hepatic steatosis to nonalcoholic steatohepatitis(NASH),wherein hepatocellular inflammation and/or fibrosis coexist with steatosis.Circulating microRNA(miRNA)levels have been suggested to be altered in NAFLD,but the extent to which miRNA are related to NAFLD features remains unknown.This analysis tested the hypothesis that plasma miRNAs are significantly associated with histological features of NAFLD in adolescents.AIM To investigate the relationship between plasma miRNA expression and NAFLD features among adolescents with NAFLD.METHODS This study included 81 adolescents diagnosed with NAFLD and 54 adolescents without NAFLD from the Teen-Longitudinal Assessment of Bariatric Surgery study.Intra-operative core liver biopsies were collected from participants and used to characterize histological features of NAFLD.Plasma samples were collected during surgery for miRNA profiling.A total of 843 plasma miRNAs were profiled using the HTG EdgeSeq platform.We examined associations of plasma miRNAs and NAFLD features using logistic regression after adjusting for age,sex,race,and other key covariates.Ingenuity Pathways Analysis was used to identify biological functions of miRNAs that were associated with multiple histological features of NAFLD.RESULTS We identified 16 upregulated plasma miRNAs,including miR-193a-5p and miR-193b-5p,and 22 downregulated plasma miRNAs,including miR-1282 and miR-6734-5p,in adolescents with NAFLD.Moreover,52,16,15,and 9 plasma miRNAs were associated with NASH,fibrosis,ballooning degeneration,and lobular inflammation,respectively.Collectively,16 miRNAs were associated with two or more histological features of NAFLD.Among those miRNAs,miR-411-5p was downregulated in NASH,ballooning,and fibrosis,while miR-122-5p,miR-1343-5p,miR-193a-5p,miR-193b-5p,and miR-7845-5p were consistently and positively associated with all histological features of NAFLD.Pathway analysis revealed that most common pathways of miRNAs associated with multiple NAFLD features have been associated with tumor progression,while we also identified linkages between miR-122-5p and hepatitis C virus and between miR-199b-5p and chronic hepatitis B.CONCLUSION Plasma miRNAs were associated with NAFLD features in adolescent with severe obesity.Larger studies with more heterogeneous NAFLD phenotypes are needed to evaluate miRNAs as potential biomarkers of NAFLD.
文摘Percutaneous coronary interventions have progressed through the era of plain balloon dilation, bare-metal stent insertion to drug-eluting stent treatment, which has significantly reduced the acute occlusion and restenosis rates of target vessels and improved patient prognosis, making drug-eluting stents the mainstream interventional treatment for coronary artery disease. In recent years, drug-coated balloons(DCBs) have become a new treatment strategy for coronary artery disease, and the drugs used in the coating and the coating technology have progressed in the past years. Without permanent implant, a DCB delivers antiproliferative drugs rapidly and uniformly into the vessel wall via the excipient during a single balloon dilation. Many evidence suggests that DCB angioplasty is an effective measure for dealing with in-stent restenosis and de novo lesions in small coronary vessels.As more clinical studies are published, new evidence is emerging for the use of DCB angioplasty in a wide range of coronary diseases, and the indications are expanding internationally. Based on the latest research from China and elsewhere, the Expert Writing Committee of the Chinese Expert Consensus on Clinical Applications of Drug-Coated Balloon has updated the previous DCB consensus after evidence-based discussions and meetings in terms of adequate preparation of in-stent restenosis lesions, expansion of the indications for coronary de novo lesions, and precise guidance of DCB treatment by intravascular imaging and functional evaluation.
文摘As multi-core processors become the de-facto configuration in modern computers, the adoption of SMP Virtual Machines(VMs) has been increasing, allowing for more efficient use of computing resources. However,because of existence of schedulers in both the hypervisor and the guest VMs, this creates a new research problem,viz., double scheduling. Although double scheduling may cause many issues including lock-holder preemption,v CPU stacking, CPU fragmentation, and priority inversion, prior approaches have either introduced new problems and/or addressed the problem incompletely. In this paper, we describe the design and implementation of Flex Core,a new scheduling scheme using v CPU ballooning, which dynamically adjusts the number of v CPUs of a VM at runtime. This essentially eliminates unnecessary scheduling in the hypervisor layer, and thus, boosts performance significantly. An evaluation using a complete KVM-based implementation shows that the average performance improvement for PARSEC applications on a 12-core Intel machine is approximately 52.9%, ranging from 35.4% to79.6%.