Spray cooling has proved its superior heat transfer performance in removing high heat flux for ground applications. However, the dissipation of vapor liquid mixture from the heat sur- face and the closed-loop circulat...Spray cooling has proved its superior heat transfer performance in removing high heat flux for ground applications. However, the dissipation of vapor liquid mixture from the heat sur- face and the closed-loop circulation of the coolant are two challenges in reduced or zero gravity space enviromnents. In this paper, an ejected spray cooling system for space closed-loop application was proposed and the negative pressure in the ejected condenser chamber was applied to sucking the two-phase mixture from the spray chamber. Its ground experimental setup was built and exper- imental investigations on the smooth circle heat surface with a diameter of 5 mm were conducted with distilled water as the coolant spraying from a nozzle of 0.51 mm orifice diameter at the inlet temperatures of 69.2 ℃ and 78.2 ℃ under the conditions of heat flux ranging from 69.76 W/cm2 to 311.45 W/cm2, volume flow through the spray nozzle varying from 11,22 L：h to 15.76 L·h. Work performance of the spray nozzle and heat transfer performance of the spray cooling system were analyzed; results show that this ejected spray cooling system has a good heat transfer performance and provides valid foundation for space closed-loop application in the near future.展开更多
In this paper,we perform a follow-up investigation of the solar eruption originating from active region 13575 on 2024 February 9.The primary eruption of a hot channel generates an X3.4 class flare,a full-halo coronal ...In this paper,we perform a follow-up investigation of the solar eruption originating from active region 13575 on 2024 February 9.The primary eruption of a hot channel generates an X3.4 class flare,a full-halo coronal mass ejection(CME),and an extreme-ultraviolet(EUV)wave.Interaction between the wave and a quiescent prominence(QP)leads to a large-amplitude,transverse oscillation of QP.After the transverse oscillation,QP loses equilibrium and rises up.The ascending motion of the prominence is coherently detected and tracked up to∼1.68 R_(⊙)by the Solar UltraViolet Imager onboard the GOES-16 spacecraft and up to∼2.2 R_(⊙)by the Solar Corona Imager(SCI_UV)of the LyαSolar Telescope onboard the ASO-S spacecraft.The velocity increases linearly from 12.3 to 68.5 km s^(−1)at 18:30 UT.The sympathetic eruption of QP drives the second CME with a typical three-part structure.The bright core comes from the eruptive prominence,which could be further observed up to∼3.3 R_(⊙) by the Large Angle Spectroscopic Coronagraph onboard the Solar and Heliospheric Observatory mission.The leading edge of the second CME accelerates continuously from∼120 to∼277 km s^(−1).The EUV wave plays an important role in linking the primary eruption with the sympathetic eruption.展开更多
In this study,it is aimed to develop a generic model which calculates the trajectory of the ejection seat from the jet aircraft,by taking into account the parameters that will affect the seat movement such as the seat...In this study,it is aimed to develop a generic model which calculates the trajectory of the ejection seat from the jet aircraft,by taking into account the parameters that will affect the seat movement such as the seat’s launch speed,ejection direction,ejection angle,altitude of the aircraft,distance/height from the aircraft rudder and canopy,pilot and ejection seat weight.With the model algorithm proposed,the ejection seat trajectory model was developed on MATLAB.The ejection seat trajectory model is based on point mass trajectory mathematical model.In this study,an analytical study of the problem has been made for modeling the flight trajectory of the ejection seat after it has been ejected.Past studies were used as a basis for validation and simulation.By writing a generic MATLAB code,a user interface was developed and presented to the user as a module.This generic code that has been developed could be used for simulations by users in the future by revising it in accordance with their own job descriptions.展开更多
BACKGROUND There is no available data about the trajectory of heart failure(HF)with improved ejection fraction(EF)and patient clinical outcomes in Qatar.AIM To explore the difference in characteristics and outcomes be...BACKGROUND There is no available data about the trajectory of heart failure(HF)with improved ejection fraction(EF)and patient clinical outcomes in Qatar.AIM To explore the difference in characteristics and outcomes between patients with transient and sustained improvement in left ventricular ejection fraction(LVEF)and to determine the independent predictors for sustained improvement in LVEF.METHODS This is a retrospective cohort study that was conducted at the advanced HF clinic of a tertiary care hospital in Qatar between January 2017 and December 2018.This were divided into two groups:HF with transient improvement in EF(HFtimpEF)and HF with sustained improvement in EF(HFsimpEF).RESULTS A total of 175 patients with HF and improved EF were included.Among them 136(77.7%)patients showed sustained improvement in LVEF.The remaining patients with HFtimpEF were predominantly males[37(94.9%)vs 101(74.3%),P=0.005]with a higher incidence of ischemic cardiomyopathy[32(82.1%)vs 68(50.4%),P=0.002],dyslipidemia[24(61.5%)vs 54(39.7%),P=0.03],and hypertension[34(87.2%)vs 93(68.4%),P=0.03]than those with HFsimpEF.The latter experienced significantly lower rates of hospitalization[39(28.7%)vs 20(51.3%),P=0.01]and diagnosis of new cardiovascular conditions during the follow-up(e.g.,acute coronary syndrome,stroke,decompensated HF,and atrial fibrillation)[14(10.3%)vs 10(25.6%),P=0.03]without a difference in emergency department visits or in-hospital death.Sustained improvement in LVEF was positively associated with being female[adjusted odds ratio(aOR)=6.8,95%confidence interval(CI):1.4-32.3,P=0.02],having non-ischemic etiology of HF(aOR=3.1,95%CI:1.03-9.3,P=0.04),and using a mineralocorticoid receptor antagonist(aOR=7.0,95%CI:1.50-31.8,P=0.01).CONCLUSION Patients with HFsimpEF experienced significantly lower rates of hospitalization and diagnosis of new cardiova-scular conditions than patients with HFtimpEF.Sustained improvement in LVEF was positively associated with being a female,having non-ischemic etiology of HF,and using a mineralocorticoid receptor antagonist.展开更多
We present an analysis of the magnetic mechanism of an X6.4-class confined flare in NOAA Active Region(AR)13590 on 2024 February 22.Despite a pre-existing magnetic flux rope(MFR)embedded within a null-point topology,t...We present an analysis of the magnetic mechanism of an X6.4-class confined flare in NOAA Active Region(AR)13590 on 2024 February 22.Despite a pre-existing magnetic flux rope(MFR)embedded within a null-point topology,the flare produced only a localized jet without an associated coronal mass ejection.Using data from the Solar Dynamics Observatory and nonlinear force-free field extrapolations,we traced the formation and evolution of the MFR,which developed under photospheric shearing motions but remained weakly twisted(with twist number being lower than 1.3)and below the thresholds for kink instability.Meanwhile,the MFR is located at heights where the decay index(n≤1.0)of the overlying field was insufficient to trigger torus instability.Furthermore,we calculated two important parameters measuring the non-potentiality of the AR,one is the ratio of the free energy to the potential-field energy,and the other is the ratio of the non-potential helicity to the square of the magnetic flux.Both the two parameters were significantly lower than critical values for eruptive flares.These factors,combined with the stabilizing influence of the strong overlying field,confined the MFR and limited the eruption to a jet.Our findings highlight the importance of both local magnetic properties and global energy constraints in determining the eruptive potential of solar flares.展开更多
Heart failure(HF)with preserved ejection fraction(HFpEF)has exceeded HF with reduced ejection fraction(HFrEF),becoming the most common type of HF.Unlike HFrEF,HFpEF is primarily a chronic low-grade inflammatory proces...Heart failure(HF)with preserved ejection fraction(HFpEF)has exceeded HF with reduced ejection fraction(HFrEF),becoming the most common type of HF.Unlike HFrEF,HFpEF is primarily a chronic low-grade inflammatory process closely associated with metabolic disorders.The coexistence of HFpEF and metabolic dysfunction-associated steatotic liver disease(MASLD)presents significant clinical challenges due to shared metabolic pathophysiology and complex inter-play.Management strategies for HFpEF and MASLD remain challenging.Sodium-glucose cotransporter 2 inhibitors have shown benefits in managing both conditions.Additionally,glucagon-like peptide-1 receptor agonists are being actively investigated for their potential benefits,particularly in MASLD.A comprehensive,patient-centered approach that combines metabolic and cardiova-scular care is essential for improving outcomes in patients with HFpEF and MASLD,addressing the global metabolic health challenges.展开更多
The high-pressure mercury intrusion (HPMI) experiment is widely used to assess the pore architecture oftight sandstone reservoirs. However, the conventional analysis of the high- pressure mercury intrusionhas always f...The high-pressure mercury intrusion (HPMI) experiment is widely used to assess the pore architecture oftight sandstone reservoirs. However, the conventional analysis of the high- pressure mercury intrusionhas always focused on the mercury injection curves themselves, neglecting the important geologicalinformation conveyed by the mercury ejection curves. This paper quantitatively describes the fractalcharacteristics of ejection curves by using four fractal models, i.e.,. Menger model, Thermodynamicmodel, Sierpinski model, and multi- fractal model. In comparison with mercury injection curves, weexplore the fractal significance of mercury ejection curves and define the applicability of different fractalmodels in characterizing pore architectures. Investigated tight sandstone samples can be divided intofour types (Types A, B, C and D) based on porosity, permeability, and mercury removal efficiency. Type Dsamples are unique in that they have higher permeability (>0.6 mD) but lower mercury removal effi-ciency (<35%). Fractal studies of the mercury injection curve show that it mainly reflects the pore throatcharacteristics, while the mercury ejection curve serves to reveal the pore features, and porosity andpermeability correlate well with the fractal dimension of the injection curve, while mercury removalefficiency correlates only with the Ds' value of the ejection curve. The studies on the mercury ejectioncurves also reveal that the small pores and micropores of the Type C and Type D samples are moredeveloped, with varying pore architecture. The fractal dimension Ds' value of Type D samples is greaterthan that of Type C samples, and the dissolution of Type D samples is more intense than that of Type Csamples, which further indicates that the Type D samples are smaller in pore size, rougher in surface, andwith greater difficulty for the hydrocarbon to enter, resulting in their reservoir capacity probably lessthan that of Type C samples. In this regard, the important information characterized by the mercuryejection curve should be considered in evaluating the tight sandstone reservoirs. Finally, the Menger andThermodynamic models prove to be more suitable for describing the total pore architecture, while theSierpinski model is better for characterizing the variability of the interconnected pores.展开更多
Knowing the optimal operating parameters of Stirling engines is important for efficient combustion through adaptability to changed pressures and oxygen atmospheres. In this study, the optimum operating conditions for ...Knowing the optimal operating parameters of Stirling engines is important for efficient combustion through adaptability to changed pressures and oxygen atmospheres. In this study, the optimum operating conditions for efficient combustion in a singular Stirling engine combustor at different oxygen atmospheres were investigated and determined. Numerical simulations were performed to investigate the effects of ejection ratio and pressure on combustion performance. In an oxygen/carbon dioxide atmosphere, the results show that increasing the ejection ratio substantially alters the flame distribution in the Stirling engine combustor, increasing heat transfer and external combustion efficiency. In contrast, increasing the ejection ratio reduces the average and maximum temperatures of the Stirling engine combustor. Increased pressure affects the flame distribution in the Stirling engine combustor and impedes the flow and convective heat transfer in the combustor, reducing the overall external combustion efficiency at pressures above 6.5 MPa. In an air/carbon dioxide atmosphere, an increased ejection ratio reduces the average and maximum temperatures in the Stirling engine combustor. However, the overall flame distribution does not change substantially. The external combustion efficiency tends to increase and then decrease because of two opposing factors: the increase in the convective heat transfer coefficient and the decrease in the temperature difference. Increasing pressure inhibits forced convection heat transfer in the Stirling engine combustor, reducing external combustion efficiency, which drops from 78% to 65% when pressure increases from 0.2 MPa to 0.5 MPa.展开更多
Heart failure(HF)has emerged as one of the foremost global health threats due to its intricate pathophysiological mechanisms and multifactorial etiology.Adeno-sine triphosphate(ATP)-induced cell death represents a nov...Heart failure(HF)has emerged as one of the foremost global health threats due to its intricate pathophysiological mechanisms and multifactorial etiology.Adeno-sine triphosphate(ATP)-induced cell death represents a novel form of regulated cell deaths,marked by cellular energy depletion and metabolic dysregulation stemming from excessive ATP accumulation,identifying its uniqueness compared to other cell death processes modalities such as programmed cell death and necrosis.Growing evidence suggests that ATP-induced cell death(AICD)is predominantly governed by various biological pathways,including energy meta-bolism,redox homeostasis and intracellular calcium equilibrium.Recent research has shown that AICD is crucial in HF induced by pathological conditions like myocardial infarction,ischemia-reperfusion injury,and chemotherapy.Thus,it is essential to investigate the function of AICD in the pathogenesis of HF,as this may provide a foundation for the development of targeted therapies and novel treatment strategies.This review synthesizes current advancements in under-standing the link between AICD and HF,while further elucidating its invol-vement in cardiac remodeling and HF progression.展开更多
Major solar plasma disturbances are subjected to Lomb-Scargle periodogram and wavelet analysis to determine the occurrence frequency.These disruptions include interplanetary coronal mass ejection,sudden storm commence...Major solar plasma disturbances are subjected to Lomb-Scargle periodogram and wavelet analysis to determine the occurrence frequency.These disruptions include interplanetary coronal mass ejection,sudden storm commencement,high-speed streams,corotating interaction regions,interplanetary shocks and Forbush decreases.We included information on all of the aforementioned solar disturbances for the last six solar cycles,from 1965 to 2023,for this study.Our findings reveal some intriguing and noteworthy results that clearly distinguish between even and odd-numbered solar cycles.The study suggests that the Sun behaves differently in odd and even-numbered solar cycles as it comes from the massive solar eruptions.During even-numbered solar cycles,variations with a period of∼44 days are prominently observed in addition to solar rotation(∼27 days)and extended solar(∼36 days)rotation.However,in addition to solar rotation,prolonged solar rotation,and periods of around 44 days,we also detect a number of intermittent changes with nearly comparable amplitude during the oddnumbered solar cycles.The findings also demonstrate that,in contrast to odd-numbered solar cycles,the emissions rate of these disruptions is more distinct and predictable during even-numbered solar cycles.展开更多
BACKGROUND Early diagnosis of left ventricular diastolic dysfunction(LVDD)is essential for preventing heart failure.B-type natriuretic peptide(BNP)is a viable marker for predicting LVDD,as elevated BNP levels have bee...BACKGROUND Early diagnosis of left ventricular diastolic dysfunction(LVDD)is essential for preventing heart failure.B-type natriuretic peptide(BNP)is a viable marker for predicting LVDD,as elevated BNP levels have been associated with worsening LVDD in patients with diabetes over time.However,the utility of BNP as a diagnostic marker in diabetes is controversial,as BNP levels are often low in overweight individuals.AIM To examine the effectiveness of BNP levels and fragmented QRS(fQRS)on electrocardiography for diagnosing LVDD in patients with type 2 diabetes.METHODS This retrospective cohort study included 303 patients with type 2 diabetes(67.4±12.3 years old)with preserved ejection fraction(EF)≥50%admitted to Toyama University Hospital for glycemic management and comorbidity evaluation between November 2017 and April 2021.All participants underwent plasma BNP measurement,electrocardiography,and echocardiography.Cardiologists who were blinded to the BNP results assessed the electrocardiograms and echocardiograms.Subgroup analyses were conducted for overweight individuals.RESULTS Receiver operating characteristic(ROC)curve analysis determined optimal BNP cut-off values of 34.8 pg/mL and 7.2 pg/mL for diagnosing LVDD in non-overweight[area under the ROC curve(AUC):0.70]and overweight(AUC:0.55)groups,respectively(P=0.040).In the overweight subgroup,fQRS showed greater diagnostic accuracy for LVDD(AUC:0.67),indicating moderate diagnostic utility compared with the low performance of the BNP cutoff of 35 pg/mL(AUC:0.52)(P=0.010).Multivariate analyses confirmed that fQRS was superior to BNP for LVDD diagnosis regardless of the patient’s weight.CONCLUSION A BNP level≥35 pg/mL in non-overweight individuals may be a reliable LVDD marker.Additionally,fQRS was more effective than BNP in diagnosing LVDD irrespective of the patient’s weight.fQRS can complement BNP in the early detection of LVDD,especially in overweight patients,potentially improving early detection and mitigating progression to heart failure with preserved EF in patients with type 2 diabetes.展开更多
Decameter-hectometric(DH)Type Ⅱ bursts,arising from coronal mass ejection(CME)-driven shock waves,are crucial for understanding solar-terrestrial interactions and space weather forecasting.This study provides a compr...Decameter-hectometric(DH)Type Ⅱ bursts,arising from coronal mass ejection(CME)-driven shock waves,are crucial for understanding solar-terrestrial interactions and space weather forecasting.This study provides a comprehensive statistical analysis of CMEs associated with DH type Ⅱ solar radio bursts during Solar Cycle 24(2009–2019),utilizing data from the Wind/WAVES,Solar TErrestrial RElations Observatory/SWAVES,and Solar and Heliospheric Observatory/LASCO catalogs.Analyzing 180 events,we report key spectral and kinematic properties,including a mean CME speed of(1058±531)km s^(−1) and a mean width of(288.39±99.3),with 62%classified as halo CMEs.About 12%of the total CMEs are accelerated,58%of them are decelerated,and 30%of them are constant.Similarly,CMEs having a speed≤800 km s^(−1) are constant,and those with speed≥800 km s^(−1) are decelerated.DH type Ⅱ bursts displayed a mean starting frequency of(12,169.72±4939)kHz,ending frequency of(2152.69±3022.07)kHz,bandwidth of(10,017±5353)kHz,and an average duration of(345.62±453)minutes.A power-law relationship was established between the drift rate(df/dt)and burst duration(D),characterized by df/dt=2749.07·D^(−0.88),highlighting the inverse dependence of drift rate on burst longevity.This suggests a dynamic interplay between shock parameters and the ambient solar corona.The findings underscore the persistent and robust spectral coverage of CME-driven shocks,offering new insights into their evolution and impact on the heliospheric environment.展开更多
We investigate the relationship between the magnitudes of Forbush decreases(FDs)and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray(GCR)data from Inuvick(INVK)and Magadan(MGDN)neutron monito...We investigate the relationship between the magnitudes of Forbush decreases(FDs)and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray(GCR)data from Inuvick(INVK)and Magadan(MGDN)neutron monitor(NM)stations to aid in counting the case of GCR flux intensity modulation.The FDs,obtained with an automated new computer software algorithm from daily-averaged GCR data from the IZMIRAN common website:http://cr0.izmiran.ru/common,at INVK(224)and MGDN(229)NM stations,from 1998 to 2002,were used in the present work.The associated solar-geomagnetic parameters of the same time range were obtained from the OMNI website.A statistical analytical method was employed to test the link between FD amplitudes and solargeomagnetic variables.We observed negative trends in FD-IMF,FD-SWS,FD-Kp,FD-SSN and FD-SI,while a positive relation was indicated in FD-Dst at both stations.All are statistically significant at a 95%confidence level.The results obtained here imply that solar emission characteristics impact the GCR flux intensity modulation.展开更多
Before solar eruptions,a short-term slow-rise phase is often observed,during which the pre-eruption structure ascends at speeds much greater than the photospheric motions but much less than those of the eruption phase...Before solar eruptions,a short-term slow-rise phase is often observed,during which the pre-eruption structure ascends at speeds much greater than the photospheric motions but much less than those of the eruption phase.Numerical magnetohydrodynamic (MHD) simulations of the coronal evolution driven by photospheric motions up to eruptions have been used to explain the slow-rise phase,but their bottom driving speeds are much larger than realistic photospheric values.Therefore,it remains an open question how the excessively fast bottom driving impacts the slow-rise phase.Here we modeled the slow-rise phase before eruption initiated from a continuously sheared magnetic arcade.In particular,we performed a series of experiments with the bottom driving speed unprecedentedly approaching the photospheric value of around 1 km s^(-1).The simulations confirmed that the slowrise phase is an ideal MHD process,i.e.,a manifestation of the growing expansion of the sheared arcade in the process of approaching a fully open field state.The overlying field line above the core flux has a slow-rise speed modulated by the driving speed’s magnitude but is always over an order of magnitude larger than the driving speed.The core field also expands with speed much higher than the driving speed but much lower than that of the overlying field.By incrementally reducing the bottom-driving speed to realistic photospheric values,we anticipate better matches between the simulated slow-rise speeds and some observed ones.展开更多
Partitioning the solar cycle into ascending and descending phases,we examine the solar cycle distribution of the north-south(N-S)asymmetry in the source locations of super geomagnetic storms(SGSs;Dst≤-250 nT)during 1...Partitioning the solar cycle into ascending and descending phases,we examine the solar cycle distribution of the north-south(N-S)asymmetry in the source locations of super geomagnetic storms(SGSs;Dst≤-250 nT)during 1932-2018.We found that during the ascending phases,SGS source locations were predominantly in the northern hemisphere(NH),exhibiting significant N-S asymmetry.For the SGSs in the descending phases,source locations of the SGSs dominated in the NH and N-S asymmetry was only significant in the western hemisphere.For the period from 1932 to 2018,the source locations of SGSs were predominantly in the NH,and the N-S asymmetry was significant.The cumulative numbers of SGSs originating from the two hemispheres were strongly anticorrelated during the ascending phases,descending phases,and the entire period from 1932 to 2018.For the source locations of SGSs with different intensities,significant N-S asymmetries were observed in the source location distribution.Specifically,for all SGSs,SGSs with-400 nT<Dst≤-300 nT,and SGSs with Dst≤-300 nT,the NH exhibited a higher number of events compared to the southern hemisphere(SH),indicating a dominance of SGSs in the NH.From the perspective of the evolution of N-S asymmetry with the solar cycle,the source locations of the SGSs always dominated in the NH during the ascending phases.However,during solar cycles 17-19 and 21,the source locations of the SGSs dominated in the NH,while during solar cycles 20,22,and 23 the source locations of the SGSs dominated in the SH.From the perspective of N-S asymmetry for Solar Cycles 17-23,solar activity across the two hemispheres is largely balanced.However,the solar activities manifested by CMEs that can trigger SGSs during Solar Cycles 17-23 were predominantly in the NH.Therefore,factors beyond solar activity,such as the propagation of the CMEs from the Sun to the Earth,likely contribute to the observed N-S asymmetric distribution of the source locations of SGSs.展开更多
To evaluate the accuracy of rockburst tendency classification in coal-bearing sandstone strata,this study conducted uniaxial compression loading and unloading tests on sandstone samples with four distinct grain sizes....To evaluate the accuracy of rockburst tendency classification in coal-bearing sandstone strata,this study conducted uniaxial compression loading and unloading tests on sandstone samples with four distinct grain sizes.The tests involved loading the samples to 60%,70%,and 80%of their uniaxial compressive strength,followed by unloading and reloading until failure.Key parameters such as the elastic energy index and linear elasticity criteria were derived from these tests.Additionally,rock fragments were collected to calculate their initial ejection kinetic energy,serving as a measure of rockburst tendency.The classification of rockburst tendency was conducted using grading methods based on burst energy index(WET),pre-peak stored elastic energy(PES)and experimental observations.Multi-class classification and regression analyses were applied to machine learning models using experimental data to predict rockburst tendency levels.A comparative analysis of models from two libraries revealed that the Random Forest model achieved the highest accuracy in classification,while the Ada Boost Regressor model excelled in regression predictions.This study highlights that on a laboratory scale,integrating ejection kinetic energy with the unloading ratio,failure load,W_(ET)and PES through machine learning offers a highly accurate and reliable approach for determining rockburst tendency levels.展开更多
Cardiac resynchronization therapy(CRT)reduces heart failure(HF)hospitaliz-ations and all-cause mortality in patients with HF with reduced ejection fraction with left bundle branch(LBB)block.Biventricular pacing(BVP)is...Cardiac resynchronization therapy(CRT)reduces heart failure(HF)hospitaliz-ations and all-cause mortality in patients with HF with reduced ejection fraction with left bundle branch(LBB)block.Biventricular pacing(BVP)is considered the gold standard for achieving CRT;however,approximately 30%–40%of patients do not respond to BVP-CRT.Recent studies have demonstrated that LBB pacing(LBBP)produces remarkable results in CRT.In this meta-analysis,LBBP-CRT showed better outcomes than conventional BVP-CRT,including greater QRS duration reduction and left ventricular ejection fraction improvement,along with consistently lower pacing thresholds on follow-up.Additionally,there was a grea-ter reduction in New York Heart Association class and brain natriuretic peptide levels.This study contributes to the growing body of encouraging data on LBBP-CRT from recent years.With ongoing technological advancements and increasing operator expertise,the day may not be far when LBBP-CRT becomes the standard of care rather than the exception.展开更多
We examined the heliolatitude distribution and North-South(N-S)asymmetry of Ground Level Enhancement(GLE)event source locations from 1942 to 2024,finding distinct patterns between the periods 1942–1979 and1980–2024....We examined the heliolatitude distribution and North-South(N-S)asymmetry of Ground Level Enhancement(GLE)event source locations from 1942 to 2024,finding distinct patterns between the periods 1942–1979 and1980–2024.Between 1942 and 1979,33 GLE events were recorded:5 from the southern hemisphere within[S3,S11]and 28 from the northern hemisphere within[N7,N37].The southeast quadrant was devoid of any source locations for GLE events.45.4%of the source locations of the GLE events were within the latitudinal range of[S15,N15].The remaining source locations of the GLE events were distributed at latitudes above 15°in the northern hemisphere.Between 1980 and 2024,43 GLE events were recorded:25 from the southern hemisphere and 18 from the northern hemisphere,with all events above 30°latitude originating from the northern hemisphere.Approximately 44.2%of the source locations of the GLE events were distributed within the latitudinal band[S15,N15].Over the period from 1942 to 2024,44.7%within[S15,N15],63.2%within[S20,N20],80.3%within[S25,N25],88.2%within[S30,N30],and 11.8%at latitudes above 30°.N-S asymmetry was significant at latitudes above 0°,5°,10°,15°,20°and 30°,with northern hemisphere dominance.Moreover,a strong inverse correlation exists between the number of GLE events from the northern and southern hemispheres at latitudes above 0°,5°,10°,15°,20°,25°and 30°.展开更多
BACKGROUND Left bundle branch pacing(LBBP)is a novel pacing modality of cardiac resynchronization therapy(CRT)that achieves more physiologic native ventricular activation than biventricular pacing(BiVP).AIM To explore...BACKGROUND Left bundle branch pacing(LBBP)is a novel pacing modality of cardiac resynchronization therapy(CRT)that achieves more physiologic native ventricular activation than biventricular pacing(BiVP).AIM To explore the validity of electromechanical resynchronization,clinical and echocardiographic response of LBBP-CRT.METHODS Systematic review and Meta-analysis were conducted in accordance with the standard guidelines as mentioned in detail in the methodology section.RESULTS In our analysis,the success rate of LBBP-CRT was determined to be 91.1%.LBBP CRT significantly shortened QRS duration,with significant improvement in echocardiographic parameters,including left ventricular ejection fraction,left ventricular end-diastolic diameter and left ventricular end-systolic diameter in comparison with BiVP-CRT.CONCLUSION A significant reduction in New York Heart Association class and B-type natriuretic peptide levels was also observed in the LBBP-CRT group vs BiVP-CRT group.Lastly,the LBBP-CRT cohort had a reduced pacing threshold at follow-up as compared to BiVP-CRT.展开更多
BACKGROUND Heart failure(HF),especially HF with reduced ejection fraction(HFrEF),presents complex challenges,particularly in the aging population where it often coexists with type 2 diabetes mellitus(T2DM).AIM To anal...BACKGROUND Heart failure(HF),especially HF with reduced ejection fraction(HFrEF),presents complex challenges,particularly in the aging population where it often coexists with type 2 diabetes mellitus(T2DM).AIM To analyze the effect of dapagliflozin treatment on cardiac,renal function,and safety in patients with HFrEF combined with T2DM.METHODS Patients with T2DM complicated with HFrEF who underwent treatment in our hospital from February 2018 to March 2023 were retrospectively analyzed as the subjects of this study.The propensity score matching method was used,and a total of 102 eligible samples were scaled.The clinical efficacy of the two groups was evaluated at the end of the treatment,comparing the results of blood glucose,insulin,cardiac function,markers of myocardial injury,renal function indexes,and 6-min walk test(6MWT)before and after the treatment.We compared the occurrence of adverse effects on the treatment process of the two groups of patients.The incidence of adverse outcomes in patients within six months of treatment was counted.RESULTS The overall clinical efficacy rate of patients in the study group was significantly higher than that of patients in the control group(P=0.013).After treatment,the pancreatic beta-cell function index,left ventricular ejection fraction,and glomerular filtration rate of patients in the study group were significantly higher than control group(P<0.001),while their fasting plasma glucose,2-h postprandial glucose,glycosylated hemoglobin,insulin resistance index,left ventricular end-systolic diameter,left ventricular end-diastolic diameter,cardiac troponin I,creatine kinase-MB,N-terminal pro b-type natriuretic peptide,serum creatinine,and blood urea nitrogen were significantly lower than those of the control group.After treatment,patients in the study group had a significantly higher 6MWT than those in the control group(P<0.001).Hypoglycemic reaction(P=0.647),urinary tract infection(P=0.558),gastrointestinal adverse effect(P=0.307),respiratory disturbance(P=0.558),and angioedema(P=0.647)were not statistically different.There was no significant difference between the incidence of adverse outcomes between the two groups(P=0.250).CONCLUSION Dapagliflozin significantly enhances clinical efficacy,cardiac and renal function,and ambulatory capacity in patients with HFrEF and T2DM without an increased risk of adverse effects or outcomes.展开更多
基金supported by the National Natural Science Foundation of China(No.50506003)
文摘Spray cooling has proved its superior heat transfer performance in removing high heat flux for ground applications. However, the dissipation of vapor liquid mixture from the heat sur- face and the closed-loop circulation of the coolant are two challenges in reduced or zero gravity space enviromnents. In this paper, an ejected spray cooling system for space closed-loop application was proposed and the negative pressure in the ejected condenser chamber was applied to sucking the two-phase mixture from the spray chamber. Its ground experimental setup was built and exper- imental investigations on the smooth circle heat surface with a diameter of 5 mm were conducted with distilled water as the coolant spraying from a nozzle of 0.51 mm orifice diameter at the inlet temperatures of 69.2 ℃ and 78.2 ℃ under the conditions of heat flux ranging from 69.76 W/cm2 to 311.45 W/cm2, volume flow through the spray nozzle varying from 11,22 L：h to 15.76 L·h. Work performance of the spray nozzle and heat transfer performance of the spray cooling system were analyzed; results show that this ejected spray cooling system has a good heat transfer performance and provides valid foundation for space closed-loop application in the near future.
基金supported by the Strategic Priority Research Program on Space Science,Chinese Academy of Sciencessupported by the National Key R&D Program of China 2022YFF0503003(2022YFF0503000),2021YFA1600500 (2021YFA1600502)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences,grant No.XDB0560000the National Natural Science Foundation of China (NSFC,grant Nos.12373065,12203102,12403064,and 12403068)Natural Science Foundation of Jiangsu Province (BK20231510,BK20241707)Supported by the Specialized Research Fund for State Key Laboratories,and Yunnan Key Laboratory of Solar Physics and Space Science under the grant No.YNSPCC202206
文摘In this paper,we perform a follow-up investigation of the solar eruption originating from active region 13575 on 2024 February 9.The primary eruption of a hot channel generates an X3.4 class flare,a full-halo coronal mass ejection(CME),and an extreme-ultraviolet(EUV)wave.Interaction between the wave and a quiescent prominence(QP)leads to a large-amplitude,transverse oscillation of QP.After the transverse oscillation,QP loses equilibrium and rises up.The ascending motion of the prominence is coherently detected and tracked up to∼1.68 R_(⊙)by the Solar UltraViolet Imager onboard the GOES-16 spacecraft and up to∼2.2 R_(⊙)by the Solar Corona Imager(SCI_UV)of the LyαSolar Telescope onboard the ASO-S spacecraft.The velocity increases linearly from 12.3 to 68.5 km s^(−1)at 18:30 UT.The sympathetic eruption of QP drives the second CME with a typical three-part structure.The bright core comes from the eruptive prominence,which could be further observed up to∼3.3 R_(⊙) by the Large Angle Spectroscopic Coronagraph onboard the Solar and Heliospheric Observatory mission.The leading edge of the second CME accelerates continuously from∼120 to∼277 km s^(−1).The EUV wave plays an important role in linking the primary eruption with the sympathetic eruption.
文摘In this study,it is aimed to develop a generic model which calculates the trajectory of the ejection seat from the jet aircraft,by taking into account the parameters that will affect the seat movement such as the seat’s launch speed,ejection direction,ejection angle,altitude of the aircraft,distance/height from the aircraft rudder and canopy,pilot and ejection seat weight.With the model algorithm proposed,the ejection seat trajectory model was developed on MATLAB.The ejection seat trajectory model is based on point mass trajectory mathematical model.In this study,an analytical study of the problem has been made for modeling the flight trajectory of the ejection seat after it has been ejected.Past studies were used as a basis for validation and simulation.By writing a generic MATLAB code,a user interface was developed and presented to the user as a module.This generic code that has been developed could be used for simulations by users in the future by revising it in accordance with their own job descriptions.
文摘BACKGROUND There is no available data about the trajectory of heart failure(HF)with improved ejection fraction(EF)and patient clinical outcomes in Qatar.AIM To explore the difference in characteristics and outcomes between patients with transient and sustained improvement in left ventricular ejection fraction(LVEF)and to determine the independent predictors for sustained improvement in LVEF.METHODS This is a retrospective cohort study that was conducted at the advanced HF clinic of a tertiary care hospital in Qatar between January 2017 and December 2018.This were divided into two groups:HF with transient improvement in EF(HFtimpEF)and HF with sustained improvement in EF(HFsimpEF).RESULTS A total of 175 patients with HF and improved EF were included.Among them 136(77.7%)patients showed sustained improvement in LVEF.The remaining patients with HFtimpEF were predominantly males[37(94.9%)vs 101(74.3%),P=0.005]with a higher incidence of ischemic cardiomyopathy[32(82.1%)vs 68(50.4%),P=0.002],dyslipidemia[24(61.5%)vs 54(39.7%),P=0.03],and hypertension[34(87.2%)vs 93(68.4%),P=0.03]than those with HFsimpEF.The latter experienced significantly lower rates of hospitalization[39(28.7%)vs 20(51.3%),P=0.01]and diagnosis of new cardiovascular conditions during the follow-up(e.g.,acute coronary syndrome,stroke,decompensated HF,and atrial fibrillation)[14(10.3%)vs 10(25.6%),P=0.03]without a difference in emergency department visits or in-hospital death.Sustained improvement in LVEF was positively associated with being female[adjusted odds ratio(aOR)=6.8,95%confidence interval(CI):1.4-32.3,P=0.02],having non-ischemic etiology of HF(aOR=3.1,95%CI:1.03-9.3,P=0.04),and using a mineralocorticoid receptor antagonist(aOR=7.0,95%CI:1.50-31.8,P=0.01).CONCLUSION Patients with HFsimpEF experienced significantly lower rates of hospitalization and diagnosis of new cardiova-scular conditions than patients with HFtimpEF.Sustained improvement in LVEF was positively associated with being a female,having non-ischemic etiology of HF,and using a mineralocorticoid receptor antagonist.
基金supported by Guangdong Basic and Applied Basic Research Foundation(2025A1515011353)the Specialized Research Fund for State Key Laboratory of Solar Activity and Space Weather.
文摘We present an analysis of the magnetic mechanism of an X6.4-class confined flare in NOAA Active Region(AR)13590 on 2024 February 22.Despite a pre-existing magnetic flux rope(MFR)embedded within a null-point topology,the flare produced only a localized jet without an associated coronal mass ejection.Using data from the Solar Dynamics Observatory and nonlinear force-free field extrapolations,we traced the formation and evolution of the MFR,which developed under photospheric shearing motions but remained weakly twisted(with twist number being lower than 1.3)and below the thresholds for kink instability.Meanwhile,the MFR is located at heights where the decay index(n≤1.0)of the overlying field was insufficient to trigger torus instability.Furthermore,we calculated two important parameters measuring the non-potentiality of the AR,one is the ratio of the free energy to the potential-field energy,and the other is the ratio of the non-potential helicity to the square of the magnetic flux.Both the two parameters were significantly lower than critical values for eruptive flares.These factors,combined with the stabilizing influence of the strong overlying field,confined the MFR and limited the eruption to a jet.Our findings highlight the importance of both local magnetic properties and global energy constraints in determining the eruptive potential of solar flares.
基金Supported by Wenzhou Science Technology Bureau Foundation,No.2022Y0726.
文摘Heart failure(HF)with preserved ejection fraction(HFpEF)has exceeded HF with reduced ejection fraction(HFrEF),becoming the most common type of HF.Unlike HFrEF,HFpEF is primarily a chronic low-grade inflammatory process closely associated with metabolic disorders.The coexistence of HFpEF and metabolic dysfunction-associated steatotic liver disease(MASLD)presents significant clinical challenges due to shared metabolic pathophysiology and complex inter-play.Management strategies for HFpEF and MASLD remain challenging.Sodium-glucose cotransporter 2 inhibitors have shown benefits in managing both conditions.Additionally,glucagon-like peptide-1 receptor agonists are being actively investigated for their potential benefits,particularly in MASLD.A comprehensive,patient-centered approach that combines metabolic and cardiova-scular care is essential for improving outcomes in patients with HFpEF and MASLD,addressing the global metabolic health challenges.
基金The research project was co-funded by the National Natural Science Foundation of China(No.42072172,No.41772120)Shandong Province Natural Science Fund for Distinguished Young Scholars(No.JQ201311)the Graduate Scientific and Technological Innovation Project Financially Supported by Shandong University of Science and Technology(No.SDKDYC190313).
文摘The high-pressure mercury intrusion (HPMI) experiment is widely used to assess the pore architecture oftight sandstone reservoirs. However, the conventional analysis of the high- pressure mercury intrusionhas always focused on the mercury injection curves themselves, neglecting the important geologicalinformation conveyed by the mercury ejection curves. This paper quantitatively describes the fractalcharacteristics of ejection curves by using four fractal models, i.e.,. Menger model, Thermodynamicmodel, Sierpinski model, and multi- fractal model. In comparison with mercury injection curves, weexplore the fractal significance of mercury ejection curves and define the applicability of different fractalmodels in characterizing pore architectures. Investigated tight sandstone samples can be divided intofour types (Types A, B, C and D) based on porosity, permeability, and mercury removal efficiency. Type Dsamples are unique in that they have higher permeability (>0.6 mD) but lower mercury removal effi-ciency (<35%). Fractal studies of the mercury injection curve show that it mainly reflects the pore throatcharacteristics, while the mercury ejection curve serves to reveal the pore features, and porosity andpermeability correlate well with the fractal dimension of the injection curve, while mercury removalefficiency correlates only with the Ds' value of the ejection curve. The studies on the mercury ejectioncurves also reveal that the small pores and micropores of the Type C and Type D samples are moredeveloped, with varying pore architecture. The fractal dimension Ds' value of Type D samples is greaterthan that of Type C samples, and the dissolution of Type D samples is more intense than that of Type Csamples, which further indicates that the Type D samples are smaller in pore size, rougher in surface, andwith greater difficulty for the hydrocarbon to enter, resulting in their reservoir capacity probably lessthan that of Type C samples. In this regard, the important information characterized by the mercuryejection curve should be considered in evaluating the tight sandstone reservoirs. Finally, the Menger andThermodynamic models prove to be more suitable for describing the total pore architecture, while theSierpinski model is better for characterizing the variability of the interconnected pores.
基金Supported by the Shanghai Rising Star Program (Grant No. 21QB1403900)the Shanghai Municipal Commission of Science and Technology (Grant No. 22170712600)。
文摘Knowing the optimal operating parameters of Stirling engines is important for efficient combustion through adaptability to changed pressures and oxygen atmospheres. In this study, the optimum operating conditions for efficient combustion in a singular Stirling engine combustor at different oxygen atmospheres were investigated and determined. Numerical simulations were performed to investigate the effects of ejection ratio and pressure on combustion performance. In an oxygen/carbon dioxide atmosphere, the results show that increasing the ejection ratio substantially alters the flame distribution in the Stirling engine combustor, increasing heat transfer and external combustion efficiency. In contrast, increasing the ejection ratio reduces the average and maximum temperatures of the Stirling engine combustor. Increased pressure affects the flame distribution in the Stirling engine combustor and impedes the flow and convective heat transfer in the combustor, reducing the overall external combustion efficiency at pressures above 6.5 MPa. In an air/carbon dioxide atmosphere, an increased ejection ratio reduces the average and maximum temperatures in the Stirling engine combustor. However, the overall flame distribution does not change substantially. The external combustion efficiency tends to increase and then decrease because of two opposing factors: the increase in the convective heat transfer coefficient and the decrease in the temperature difference. Increasing pressure inhibits forced convection heat transfer in the Stirling engine combustor, reducing external combustion efficiency, which drops from 78% to 65% when pressure increases from 0.2 MPa to 0.5 MPa.
基金Supported by Science and Technology Department of Yunnan Province-Kunming Medical University,Kunming Medical Joint Special Project-Surface Project,No.202401AY070001-164Yunnan Provincial Clinical Research Center Cardiovascular Diseases-New Technology Research for Development Project for Diagnosis and Treatment Cardiovascular Diseases,No.202102AA310002the Key Technology Research and Device Development Project for Innovative Diagnosis and Treatment of Structural Heart Disease in the Southwest Plateau Region,No.202302AA310045.
文摘Heart failure(HF)has emerged as one of the foremost global health threats due to its intricate pathophysiological mechanisms and multifactorial etiology.Adeno-sine triphosphate(ATP)-induced cell death represents a novel form of regulated cell deaths,marked by cellular energy depletion and metabolic dysregulation stemming from excessive ATP accumulation,identifying its uniqueness compared to other cell death processes modalities such as programmed cell death and necrosis.Growing evidence suggests that ATP-induced cell death(AICD)is predominantly governed by various biological pathways,including energy meta-bolism,redox homeostasis and intracellular calcium equilibrium.Recent research has shown that AICD is crucial in HF induced by pathological conditions like myocardial infarction,ischemia-reperfusion injury,and chemotherapy.Thus,it is essential to investigate the function of AICD in the pathogenesis of HF,as this may provide a foundation for the development of targeted therapies and novel treatment strategies.This review synthesizes current advancements in under-standing the link between AICD and HF,while further elucidating its invol-vement in cardiac remodeling and HF progression.
文摘Major solar plasma disturbances are subjected to Lomb-Scargle periodogram and wavelet analysis to determine the occurrence frequency.These disruptions include interplanetary coronal mass ejection,sudden storm commencement,high-speed streams,corotating interaction regions,interplanetary shocks and Forbush decreases.We included information on all of the aforementioned solar disturbances for the last six solar cycles,from 1965 to 2023,for this study.Our findings reveal some intriguing and noteworthy results that clearly distinguish between even and odd-numbered solar cycles.The study suggests that the Sun behaves differently in odd and even-numbered solar cycles as it comes from the massive solar eruptions.During even-numbered solar cycles,variations with a period of∼44 days are prominently observed in addition to solar rotation(∼27 days)and extended solar(∼36 days)rotation.However,in addition to solar rotation,prolonged solar rotation,and periods of around 44 days,we also detect a number of intermittent changes with nearly comparable amplitude during the oddnumbered solar cycles.The findings also demonstrate that,in contrast to odd-numbered solar cycles,the emissions rate of these disruptions is more distinct and predictable during even-numbered solar cycles.
基金Supported by the JSPS KAKENHI,No.JP21K10300 and No.JP24K02714.
文摘BACKGROUND Early diagnosis of left ventricular diastolic dysfunction(LVDD)is essential for preventing heart failure.B-type natriuretic peptide(BNP)is a viable marker for predicting LVDD,as elevated BNP levels have been associated with worsening LVDD in patients with diabetes over time.However,the utility of BNP as a diagnostic marker in diabetes is controversial,as BNP levels are often low in overweight individuals.AIM To examine the effectiveness of BNP levels and fragmented QRS(fQRS)on electrocardiography for diagnosing LVDD in patients with type 2 diabetes.METHODS This retrospective cohort study included 303 patients with type 2 diabetes(67.4±12.3 years old)with preserved ejection fraction(EF)≥50%admitted to Toyama University Hospital for glycemic management and comorbidity evaluation between November 2017 and April 2021.All participants underwent plasma BNP measurement,electrocardiography,and echocardiography.Cardiologists who were blinded to the BNP results assessed the electrocardiograms and echocardiograms.Subgroup analyses were conducted for overweight individuals.RESULTS Receiver operating characteristic(ROC)curve analysis determined optimal BNP cut-off values of 34.8 pg/mL and 7.2 pg/mL for diagnosing LVDD in non-overweight[area under the ROC curve(AUC):0.70]and overweight(AUC:0.55)groups,respectively(P=0.040).In the overweight subgroup,fQRS showed greater diagnostic accuracy for LVDD(AUC:0.67),indicating moderate diagnostic utility compared with the low performance of the BNP cutoff of 35 pg/mL(AUC:0.52)(P=0.010).Multivariate analyses confirmed that fQRS was superior to BNP for LVDD diagnosis regardless of the patient’s weight.CONCLUSION A BNP level≥35 pg/mL in non-overweight individuals may be a reliable LVDD marker.Additionally,fQRS was more effective than BNP in diagnosing LVDD irrespective of the patient’s weight.fQRS can complement BNP in the early detection of LVDD,especially in overweight patients,potentially improving early detection and mitigating progression to heart failure with preserved EF in patients with type 2 diabetes.
基金supported by the National Key R&D Program of China(2021YFA1600500 and 2021YFA1600503)sponsored by the CAS-TWAS President Fellowship Programpartially supported by the Tianchi Talent Program of the Xinjiang Uygur Autonomous Region of China.
文摘Decameter-hectometric(DH)Type Ⅱ bursts,arising from coronal mass ejection(CME)-driven shock waves,are crucial for understanding solar-terrestrial interactions and space weather forecasting.This study provides a comprehensive statistical analysis of CMEs associated with DH type Ⅱ solar radio bursts during Solar Cycle 24(2009–2019),utilizing data from the Wind/WAVES,Solar TErrestrial RElations Observatory/SWAVES,and Solar and Heliospheric Observatory/LASCO catalogs.Analyzing 180 events,we report key spectral and kinematic properties,including a mean CME speed of(1058±531)km s^(−1) and a mean width of(288.39±99.3),with 62%classified as halo CMEs.About 12%of the total CMEs are accelerated,58%of them are decelerated,and 30%of them are constant.Similarly,CMEs having a speed≤800 km s^(−1) are constant,and those with speed≥800 km s^(−1) are decelerated.DH type Ⅱ bursts displayed a mean starting frequency of(12,169.72±4939)kHz,ending frequency of(2152.69±3022.07)kHz,bandwidth of(10,017±5353)kHz,and an average duration of(345.62±453)minutes.A power-law relationship was established between the drift rate(df/dt)and burst duration(D),characterized by df/dt=2749.07·D^(−0.88),highlighting the inverse dependence of drift rate on burst longevity.This suggests a dynamic interplay between shock parameters and the ambient solar corona.The findings underscore the persistent and robust spectral coverage of CME-driven shocks,offering new insights into their evolution and impact on the heliospheric environment.
文摘We investigate the relationship between the magnitudes of Forbush decreases(FDs)and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray(GCR)data from Inuvick(INVK)and Magadan(MGDN)neutron monitor(NM)stations to aid in counting the case of GCR flux intensity modulation.The FDs,obtained with an automated new computer software algorithm from daily-averaged GCR data from the IZMIRAN common website:http://cr0.izmiran.ru/common,at INVK(224)and MGDN(229)NM stations,from 1998 to 2002,were used in the present work.The associated solar-geomagnetic parameters of the same time range were obtained from the OMNI website.A statistical analytical method was employed to test the link between FD amplitudes and solargeomagnetic variables.We observed negative trends in FD-IMF,FD-SWS,FD-Kp,FD-SSN and FD-SI,while a positive relation was indicated in FD-Dst at both stations.All are statistically significant at a 95%confidence level.The results obtained here imply that solar emission characteristics impact the GCR flux intensity modulation.
基金supported by the National Natural Science Foundation of China (NSFC,Grant No.42174200)Shenzhen Science and Technology Program (grant No.RCJC20210609104422048)+1 种基金Shenzhen Key Laboratory Launching Project (No.ZDSYS20210702140800001)Guangdong Basic and Applied Basic Research Foundation(2023B1515040021)。
文摘Before solar eruptions,a short-term slow-rise phase is often observed,during which the pre-eruption structure ascends at speeds much greater than the photospheric motions but much less than those of the eruption phase.Numerical magnetohydrodynamic (MHD) simulations of the coronal evolution driven by photospheric motions up to eruptions have been used to explain the slow-rise phase,but their bottom driving speeds are much larger than realistic photospheric values.Therefore,it remains an open question how the excessively fast bottom driving impacts the slow-rise phase.Here we modeled the slow-rise phase before eruption initiated from a continuously sheared magnetic arcade.In particular,we performed a series of experiments with the bottom driving speed unprecedentedly approaching the photospheric value of around 1 km s^(-1).The simulations confirmed that the slowrise phase is an ideal MHD process,i.e.,a manifestation of the growing expansion of the sheared arcade in the process of approaching a fully open field state.The overlying field line above the core flux has a slow-rise speed modulated by the driving speed’s magnitude but is always over an order of magnitude larger than the driving speed.The core field also expands with speed much higher than the driving speed but much lower than that of the overlying field.By incrementally reducing the bottom-driving speed to realistic photospheric values,we anticipate better matches between the simulated slow-rise speeds and some observed ones.
基金supported by the National Natural Science Foundation of China(NSFC,grant Nos.41774085,41074132,41274193 and 41674166)the Special Fund of the Institute of Geophysics,China Earthquake Administration(grant Nos.DQJB22X12 and DQJB24X25)。
文摘Partitioning the solar cycle into ascending and descending phases,we examine the solar cycle distribution of the north-south(N-S)asymmetry in the source locations of super geomagnetic storms(SGSs;Dst≤-250 nT)during 1932-2018.We found that during the ascending phases,SGS source locations were predominantly in the northern hemisphere(NH),exhibiting significant N-S asymmetry.For the SGSs in the descending phases,source locations of the SGSs dominated in the NH and N-S asymmetry was only significant in the western hemisphere.For the period from 1932 to 2018,the source locations of SGSs were predominantly in the NH,and the N-S asymmetry was significant.The cumulative numbers of SGSs originating from the two hemispheres were strongly anticorrelated during the ascending phases,descending phases,and the entire period from 1932 to 2018.For the source locations of SGSs with different intensities,significant N-S asymmetries were observed in the source location distribution.Specifically,for all SGSs,SGSs with-400 nT<Dst≤-300 nT,and SGSs with Dst≤-300 nT,the NH exhibited a higher number of events compared to the southern hemisphere(SH),indicating a dominance of SGSs in the NH.From the perspective of the evolution of N-S asymmetry with the solar cycle,the source locations of the SGSs always dominated in the NH during the ascending phases.However,during solar cycles 17-19 and 21,the source locations of the SGSs dominated in the NH,while during solar cycles 20,22,and 23 the source locations of the SGSs dominated in the SH.From the perspective of N-S asymmetry for Solar Cycles 17-23,solar activity across the two hemispheres is largely balanced.However,the solar activities manifested by CMEs that can trigger SGSs during Solar Cycles 17-23 were predominantly in the NH.Therefore,factors beyond solar activity,such as the propagation of the CMEs from the Sun to the Earth,likely contribute to the observed N-S asymmetric distribution of the source locations of SGSs.
基金financial support for this work provided by the National Natural Science Foundation of China (No.52227901)。
文摘To evaluate the accuracy of rockburst tendency classification in coal-bearing sandstone strata,this study conducted uniaxial compression loading and unloading tests on sandstone samples with four distinct grain sizes.The tests involved loading the samples to 60%,70%,and 80%of their uniaxial compressive strength,followed by unloading and reloading until failure.Key parameters such as the elastic energy index and linear elasticity criteria were derived from these tests.Additionally,rock fragments were collected to calculate their initial ejection kinetic energy,serving as a measure of rockburst tendency.The classification of rockburst tendency was conducted using grading methods based on burst energy index(WET),pre-peak stored elastic energy(PES)and experimental observations.Multi-class classification and regression analyses were applied to machine learning models using experimental data to predict rockburst tendency levels.A comparative analysis of models from two libraries revealed that the Random Forest model achieved the highest accuracy in classification,while the Ada Boost Regressor model excelled in regression predictions.This study highlights that on a laboratory scale,integrating ejection kinetic energy with the unloading ratio,failure load,W_(ET)and PES through machine learning offers a highly accurate and reliable approach for determining rockburst tendency levels.
文摘Cardiac resynchronization therapy(CRT)reduces heart failure(HF)hospitaliz-ations and all-cause mortality in patients with HF with reduced ejection fraction with left bundle branch(LBB)block.Biventricular pacing(BVP)is considered the gold standard for achieving CRT;however,approximately 30%–40%of patients do not respond to BVP-CRT.Recent studies have demonstrated that LBB pacing(LBBP)produces remarkable results in CRT.In this meta-analysis,LBBP-CRT showed better outcomes than conventional BVP-CRT,including greater QRS duration reduction and left ventricular ejection fraction improvement,along with consistently lower pacing thresholds on follow-up.Additionally,there was a grea-ter reduction in New York Heart Association class and brain natriuretic peptide levels.This study contributes to the growing body of encouraging data on LBBP-CRT from recent years.With ongoing technological advancements and increasing operator expertise,the day may not be far when LBBP-CRT becomes the standard of care rather than the exception.
基金supported by the National Natural Science Foundation of China(grant Nos.42374092,41074132,41274193,41474166,41774195,and 41874187)the Special Fund of the Institute of Geophysics,China Earthquake Administration(Grant Number DQJB22X12)。
文摘We examined the heliolatitude distribution and North-South(N-S)asymmetry of Ground Level Enhancement(GLE)event source locations from 1942 to 2024,finding distinct patterns between the periods 1942–1979 and1980–2024.Between 1942 and 1979,33 GLE events were recorded:5 from the southern hemisphere within[S3,S11]and 28 from the northern hemisphere within[N7,N37].The southeast quadrant was devoid of any source locations for GLE events.45.4%of the source locations of the GLE events were within the latitudinal range of[S15,N15].The remaining source locations of the GLE events were distributed at latitudes above 15°in the northern hemisphere.Between 1980 and 2024,43 GLE events were recorded:25 from the southern hemisphere and 18 from the northern hemisphere,with all events above 30°latitude originating from the northern hemisphere.Approximately 44.2%of the source locations of the GLE events were distributed within the latitudinal band[S15,N15].Over the period from 1942 to 2024,44.7%within[S15,N15],63.2%within[S20,N20],80.3%within[S25,N25],88.2%within[S30,N30],and 11.8%at latitudes above 30°.N-S asymmetry was significant at latitudes above 0°,5°,10°,15°,20°and 30°,with northern hemisphere dominance.Moreover,a strong inverse correlation exists between the number of GLE events from the northern and southern hemispheres at latitudes above 0°,5°,10°,15°,20°,25°and 30°.
文摘BACKGROUND Left bundle branch pacing(LBBP)is a novel pacing modality of cardiac resynchronization therapy(CRT)that achieves more physiologic native ventricular activation than biventricular pacing(BiVP).AIM To explore the validity of electromechanical resynchronization,clinical and echocardiographic response of LBBP-CRT.METHODS Systematic review and Meta-analysis were conducted in accordance with the standard guidelines as mentioned in detail in the methodology section.RESULTS In our analysis,the success rate of LBBP-CRT was determined to be 91.1%.LBBP CRT significantly shortened QRS duration,with significant improvement in echocardiographic parameters,including left ventricular ejection fraction,left ventricular end-diastolic diameter and left ventricular end-systolic diameter in comparison with BiVP-CRT.CONCLUSION A significant reduction in New York Heart Association class and B-type natriuretic peptide levels was also observed in the LBBP-CRT group vs BiVP-CRT group.Lastly,the LBBP-CRT cohort had a reduced pacing threshold at follow-up as compared to BiVP-CRT.
文摘BACKGROUND Heart failure(HF),especially HF with reduced ejection fraction(HFrEF),presents complex challenges,particularly in the aging population where it often coexists with type 2 diabetes mellitus(T2DM).AIM To analyze the effect of dapagliflozin treatment on cardiac,renal function,and safety in patients with HFrEF combined with T2DM.METHODS Patients with T2DM complicated with HFrEF who underwent treatment in our hospital from February 2018 to March 2023 were retrospectively analyzed as the subjects of this study.The propensity score matching method was used,and a total of 102 eligible samples were scaled.The clinical efficacy of the two groups was evaluated at the end of the treatment,comparing the results of blood glucose,insulin,cardiac function,markers of myocardial injury,renal function indexes,and 6-min walk test(6MWT)before and after the treatment.We compared the occurrence of adverse effects on the treatment process of the two groups of patients.The incidence of adverse outcomes in patients within six months of treatment was counted.RESULTS The overall clinical efficacy rate of patients in the study group was significantly higher than that of patients in the control group(P=0.013).After treatment,the pancreatic beta-cell function index,left ventricular ejection fraction,and glomerular filtration rate of patients in the study group were significantly higher than control group(P<0.001),while their fasting plasma glucose,2-h postprandial glucose,glycosylated hemoglobin,insulin resistance index,left ventricular end-systolic diameter,left ventricular end-diastolic diameter,cardiac troponin I,creatine kinase-MB,N-terminal pro b-type natriuretic peptide,serum creatinine,and blood urea nitrogen were significantly lower than those of the control group.After treatment,patients in the study group had a significantly higher 6MWT than those in the control group(P<0.001).Hypoglycemic reaction(P=0.647),urinary tract infection(P=0.558),gastrointestinal adverse effect(P=0.307),respiratory disturbance(P=0.558),and angioedema(P=0.647)were not statistically different.There was no significant difference between the incidence of adverse outcomes between the two groups(P=0.250).CONCLUSION Dapagliflozin significantly enhances clinical efficacy,cardiac and renal function,and ambulatory capacity in patients with HFrEF and T2DM without an increased risk of adverse effects or outcomes.
